[beta]-silicon carbide protective coating and method for fabricating same

DOEpatents

Carey, P.G.; Thompson, J.B.

1994-11-01

A polycrystalline beta-silicon carbide film or coating and method for forming same on components, such as the top of solar cells, to act as an extremely hard protective surface, and as an anti-reflective coating are disclosed. This is achieved by DC magnetron co-sputtering of amorphous silicon and carbon to form a SiC thin film onto a surface, such as a solar cell. The thin film is then irradiated by a pulsed energy source, such as an excimer laser, to synthesize the poly- or [mu]c-SiC film on the surface and produce [beta]-SiC. While the method of this invention has primary application in solar cell manufacturing, it has application wherever there is a requirement for an extremely hard surface. 3 figs.

Agglutination of like-charged red blood cells induced by binding of beta2-glycoprotein I to outer cell surface.

PubMed

Lokar, Marusa; Urbanija, Jasna; Frank, Mojca; Hägerstrand, Henry; Rozman, Blaz; Bobrowska-Hägerstrand, Malgorzata; Iglic, Ales; Kralj-Iglic, Veronika

2008-08-01

Plasma protein-mediated attractive interaction between membranes of red blood cells (RBCs) and phospholipid vesicles was studied. It is shown that beta(2)-glycoprotein I (beta(2)-GPI) may induce RBC discocyte-echinocyte-spherocyte shape transformation and subsequent agglutination of RBCs. Based on the observed beta(2)-GPI-induced RBC cell shape transformation it is proposed that the hydrophobic portion of beta(2)-GPI molecule protrudes into the outer lipid layer of the RBC membrane and increases the area of this layer. It is also suggested that the observed agglutination of RBCs is at least partially driven by an attractive force which is of electrostatic origin and depends on the specific molecular shape and internal charge distribution of membrane-bound beta(2)-GPI molecules. The suggested beta(2)-GPI-induced attractive electrostatic interaction between like-charged RBC membrane surfaces is qualitatively explained by using a simple mathematical model within the functional density theory of the electric double layer, where the electrostatic attraction between the positively charged part of the first domains of bound beta(2)-GPI molecules and negatively charged glycocalyx of the adjacent RBC membrane is taken into account.

Segregation of two spectrin isoforms: polarized membrane-binding sites direct polarized membrane skeleton assembly.

PubMed

Dubreuil, R R; Maddux, P B; Grushko, T A; MacVicar, G R

1997-10-01

Spectrin isoforms are often segregated within specialized plasma membrane subdomains where they are thought to contribute to the development of cell surface polarity. It was previously shown that ankyrin and beta spectrin are recruited to sites of cell-cell contact in Drosophila S2 cells expressing the homophilic adhesion molecule neuroglian. Here, we show that neuroglian has no apparent effect on a second spectrin isoform (alpha beta H), which is constitutively associated with the plasma membrane in S2 cells. Another membrane marker, the Na,K-ATPase, codistributes with ankyrin and alpha beta spectrin at sites of neuroglian-mediated contact. The distributions of these markers in epithelial cells in vivo are consistent with the order of events observed in S2 cells. Neuroglian, ankyrin, alpha beta spectrin, and the Na,K-ATPase colocalize at the lateral domain of salivary gland cells. In contrast, alpha beta H spectrin is sorted to the apical domain of salivary gland and somatic follicle cells. Thus, the two spectrin isoforms respond independently to positional cues at the cell surface: in one case an apically sorted receptor and in the other case a locally activated cell-cell adhesion molecule. The results support a model in which the membrane skeleton behaves as a transducer of positional information within cells.

Expression profile of senescence-associated beta-galactosidase and activation of telomerase in human ovarian surface epithelial cells undergoing immortalization.

PubMed

Litaker, J R; Pan, J; Cheung, Y; Zhang, D K; Liu, Y; Wong, S C; Wan, T S; Tsao, S W

1998-11-01

Senescence is a specific physiological stage of cells characterized by long population doubling time. It accounts for the inability of normal somatic cells to undergo indefinite cell division. As the number of population doublings increase, cell cycle regulatory mechanisms come into play and signal cells to exit the cell cycle and become senescent. Senescence has been implicated in the aging process and may function as a tumor suppressor mechanism in human cells. The ability to measure the degree of cellular senescence is important in understanding the biological processes regulating cell aging and immortalization. Senescent cells exhibit an enzyme termed senescence-associated histochemical staining. Cells immortalized by viral oncogenes often enter a stage of crisis at the early phase of immortalization. The cells at crisis have a long population doubling time. Cells at the crisis stage resemble senescent cells and the expression of SA- beta-Gal may be used to monitor the process of immortalization. In this study the expression profile of SA-beta-Gal was examined in human ovarian surface epithelial cells (HOSE 6-3) undergoing immortalization by the human papilloma viral oncogene E6 and E7 (HPV E6 and E7). Our results showed a low percentage (12.0%) of HOSE 6-3 cells expressing SA-beta-Gal activity at the pre-crisis stage. The percentage of HOSE 6-3 cells expressing SA-beta-Gal activity was highest (39.2%) at the crisis stage. When HOSE 6-3 cells achieved immortalized status there was a sharp decrease in cells (1. 3%) expressing SA-beta-Gal activity. In addition, an inverse relationship between the expression of SA-beta-Gal activity and telomerase activity was noted in cells undergoing immortalization. The results confirm that the SA-beta-Gal enzyme is a good marker for monitoring the population of cells undergoing senescence at different stages of immortalization and that telomerase activation is a characteristic feature of post-crisis cells.

Activation of the novel estrogen receptor G protein-coupled receptor 30 (GPR30) at the plasma membrane.

PubMed

Filardo, E; Quinn, J; Pang, Y; Graeber, C; Shaw, S; Dong, J; Thomas, P

2007-07-01

G protein-coupled receptor 30 (GPR30), a seven-transmembrane receptor (7TMR), is associated with rapid estrogen-dependent, G protein signaling and specific estrogen binding. At present, the subcellular site of GPR30 action is unclear. Previous studies using antibodies and fluorochrome-labeled estradiol (E2) have failed to detect GPR30 on the cell surface, suggesting that GPR30 may function uniquely among 7TMRs as an intracellular receptor. Here, we show that detectable expression of GPR30 on the surface of transfected HEK-293 cells can be selected by fluorescence-activated cell sorting. Expression of GPR30 on the cell surface was confirmed by confocal microscopy using the lectin concanavalin A as a plasma membrane marker. Stimulation of GPR30-expressing HEK-293 cells with 17beta-E2 caused sequestration of GPR30 from the cell surface and resulted in its codistribution with clathrin and mobilization of intracellular calcium stores. Evidence that GPR30 signals from the cell surface was obtained from experiments demonstrating that the cell-impermeable E2-protein conjugates E2-BSA and E2-horseradish peroxidase promote GPR30-dependent elevation of intracellular cAMP concentrations. Subcellular fractionation studies further support the plasma membrane as a site of GPR30 action with specific [3H]17beta-E2 binding and G protein activation associated with plasma membrane but not microsomal, or other fractions, prepared from HEK-293 or SKBR3 breast cancer cells. These results suggest that GPR30, like other 7TMRs, functions as a plasma membrane receptor.

beta 2-glycoprotein I (apolipoprotein H) modulates uptake and endocytosis associated chemiluminescence in rat Kupffer cells.

PubMed

Gomes, L F; Gonçalves, L M; Fonseca, F L A; Celli, C M; Videla, L A; Chaimovich, H; Junqueira, V B C

2002-07-01

beta 2-Glycoprotein I (beta 2 GPI) is known to influence macrophage uptake of particles with phosphatidylserine containing surfaces, as apoptotic thymocytes and unilamellar vesicles in vitro. Nevertheless, effects upon macrophage activation induced by this interaction are still unknown. beta 2 GPI influence upon the reactive species production by Kupffer cells was evaluated in order to investigate whether beta 2 GPI modulates the macrophage response to negatively charged surfaces. Chemiluminescence of isolated non-parenchymal rat liver cells was measured after phagocytosis of opsonized zymosan or phorbolymristate acetate (PMA) stimulation, in the presence and absence of large unilamellar vesicles (LUVs) containing 25 mol% phosphatidylserine (PS) or 50 mol% cardiolipin (CL) and complementary molar ratio of phosphatidylcholine (PC). beta 2 GPI decreased by 50% the chemiluminescence response induced by opsonized zymosan, with a 66% reduction of the initial light emission rate. PMA stimulated Kupffer cell chemiluminescence was insensitive to human or rat beta 2 GPI. Albumin (500 micrograms/ml) showed no effect upon chemiluminescence. beta 2 GPI increased PS/PC LUV uptake and degradation by Kupffer cells in a concentration-dependent manner, without leakage of the internal contents of the LUVs, as shown by fluorescence intensity enhancement. LUVs opsonized with antiphospholipid antibodies (aPL) from syphilitic patients increased light emission by Kupffer cells. Addition of beta 2 GPI to the assay reduced chemiluminescence due to opsonization with purified IgG antibodies from systemic lupus erythematosus (SLE or syphilis (Sy) patient sera. A marked net increase in chemiluminescence is observed in the presence of Sy aPL antibodies, whereas a decrease was found when SLE aPL were added to the assay, in the presence or absence of beta 2 GPI. At a concentration of 125 micrograms/ml, beta 2 GPI significantly reduced Kupffer cell Candida albicans phagocytosis index and killing score by 50 and 10%, respectively. The present data strongly suggest that particle uptake in the presence of beta 2 GPI is coupled to an inhibition of reactive species production by liver macrophages during the respiratory burst, supporting the role of beta 2 GPI as a mediator of senescent cell removal.

Induction of experimental bone metastasis in mice by transfection of integrin alpha 4 beta 1 into tumor cells.

PubMed Central

Matsuura, N.; Puzon-McLaughlin, W.; Irie, A.; Morikawa, Y.; Kakudo, K.; Takada, Y.

1996-01-01

Cell adhesion receptors (eg, integrins and CD44) play an important role in invasion and metastasis during tumor progression. The increase in integrin alpha 4 beta 1 expression on primary melanomas has been reported to significantly correlate with the development of metastases. alpha 4 beta 1 is a cell surface heterodimer that mediates cell-cell and cell-extracellular matrix interactions through adhesion to vascular cell adhesion molecule (VCAM)-1 and to the IIICS region of fibronectin. To test the effects of alpha 4 beta 1 expression on tumor cell metastasis, Chinese hamster ovary cells were transfected with human alpha 4 cDNA. Whereas alpha 4-negative Chinese hamster ovary cells developed only pulmonary metastasis, alpha 4-positive Chinese hamster ovary cells developed bone and pulmonary metastasis in 3 to 4 weeks when injected intravenously into nude mice. Bone metastasis was inhibited by antibody against alpha 4 or VCAM-1. Expression of alpha 3 beta 1, alpha 6 beta 1, or alpha V beta 1 did not induce bone metastasis. Expression of alpha 4 beta 1 also induced bone metastasis in K562 human erythroleukemia cells injected into SCID mice. These results demonstrate that alpha 4 beta 1 can induce tumor cell trafficking to bone, probably via interaction with VCAM-1 that is constitutively expressed on bone marrow stromal cells. Images Figure 1 Figure 3 PMID:8546226

Insulin release: the receptor hypothesis.

PubMed

Malaisse, Willy J

2014-07-01

It is currently believed that the stimulation of insulin release by nutrient secretagogues reflects their capacity to act as fuel in pancreatic islet beta cells. In this review, it is proposed that such a fuel concept is not incompatible with a receptor hypothesis postulating the participation of cell-surface receptors in the recognition of selected nutrients as insulinotropic agents. Pursuant to this, attention is drawn to such matters as the anomeric specificity of the beta cell secretory response to D-glucose and its perturbation in diabetes mellitus, the insulinotropic action of artificial sweeteners, the possible role of bitter taste receptors in the stimulation of insulin secretion by L-glucose pentaacetate, the recently documented presence of cell-surface sweet taste receptors in insulin-producing cells, the multimodal signalling process resulting from the activation of these latter receptors, and the presence in beta cells of a sweet taste receptor mediating the fructose-induced potentiation of glucose-stimulated insulin secretion.

Functional integrins from normal and glycosylation-deficient baby hamster kidney cells. Terminal processing of asparagine-linked oligosaccharides is not correlated with fibronectin-binding activity.

PubMed

Koyama, T; Hughes, R C

1992-12-25

We have examined the properties of the alpha 5 beta 1 integrin of baby hamster kidney (BHK) cells, a ricin-resistant variant Ric14 lacking N-acetylglucosaminyl transferase I, and hence unable to complete assembly of hybrid- or complex-type N-glycans, and BHK cells treated with 1-deoxymannojirimycin (dMM), an inhibitor of Golgi mannosidases involved in the initial processing of N-glycan precursors. Comparable amounts of alpha 5 beta 1 integrin were isolated from these cells by chromatography of detergent extracts on a fibronectin cell-binding fragment affinity column and elution with EDTA. The alpha 5 beta 1 integrin obtained from normal BHK cells by fibronectin affinity chromatography contained mainly endoglycosidase H-resistant oligosaccharides, whereas in RicR14 cells or dMM-treated BHK cells these were entirely endoglycosidase H-sensitive. Analysis of lactoperoxidase labeled or long term biosynthetically 35S-labeled proteins from cultures of normal or glycosylation deficient cells showed similar steady state levels of alpha 5 beta 1 integrin and expression at the cell surface. Pulse-chase experiments in normal BHK cells showed rapid conversion of the alpha 5 subunit into a mature form containing oligosaccharides resistant to endoglycosidase H and slower maturation of a precursor beta 1 subunit, as in other cell types. In Ric14 cells the precursor beta 1 subunit was found to carry glycans larger than the fully processed Man5GlcNAc2 glycan of the mature subunit, indicating that the bulk precursor pool had not been translocated into the cis-Golgi compartment containing mannosidase I. We conclude that in BHK cells terminal oligosaccharide processing of alpha 5 beta 1 integrin subunits is not required for dimer formation, surface expression, and fibronectin binding, and that expression of the glycosylation defect of Ric14 cells on the alpha 5 beta 1 integrin does not account for the reduced adhesiveness of these cells on fibronectin compared with normal and dMM-treated BHK cells.

Mechanism of abnormal growth in astrocytes derived from a mouse model of GM2 gangliosidosis.

PubMed

Kawashima, Nagako; Tsuji, Daisuke; Okuda, Tetsuya; Itoh, Kohji; Nakayama, Ken-ichi

2009-11-01

Sandhoff disease is a progressive neurodegenerative disorder caused by mutations in the HEXB gene which encodes the beta-subunit of N-acetyl-beta-hexosaminidase A and B, resulting in the accumulation of the ganglioside GM2. We isolated astrocytes from the neonatal brain of Sandhoff disease model mice in which the N-acetyl-beta-hexosaminidase beta-subunit gene is genetically disrupted (ASD). Glycolipid profiles revealed that GM2/GA2 accumulated in the lysosomes and not on the cell surface of ASD astrocytes. In addition, GM3 was increased on the cell surface. We found remarkable differences in the cell proliferation of ASD astrocytes when compared with cells isolated from wild-type mice, with a faster growth rate of ASD cells. In addition, we observed increased extracellular, signal-regulated kinase (ERK) phosphorylation in ASD cells, but Akt phosphorylation was decreased. Furthermore, the phosphorylation of ERK in ASD cells was not dependent upon extracellular growth factors. Treatment of ASD astrocytes with recombinant N-acetyl-beta-hexosaminidase A resulted in a decrease of their growth rate and ERK phosphorylation. These results indicated that the up-regulation of ERK phosphorylation and the increase in proliferation of ASD astrocytes were dependent upon GM2/GA2 accumulation. These findings may represent a mechanism in linking the nerve cell death and reactive gliosis observed in Sandhoff disease.

The deubiquitinases USP33 and USP20 coordinate beta2 adrenergic receptor recycling and resensitization.

PubMed

Berthouze, Magali; Venkataramanan, Vidya; Li, Yi; Shenoy, Sudha K

2009-06-17

Agonist-induced ubiquitination of the beta(2) adrenergic receptor (beta(2)AR) functions as an important post-translational modification to sort internalized receptors to the lysosomes for degradation. We now show that this ubiquitination is reversed by two deubiquitinating enzymes, ubiquitin-specific proteases (USPs) 20 and 33, thus, inhibiting lysosomal trafficking when concomitantly promoting receptor recycling from the late-endosomal compartments as well as resensitization of recycled receptors at the cell surface. Dissociation of constitutively bound endogenously expressed USPs 20 and 33 from the beta(2)AR immediately after agonist stimulation and reassociation on prolonged agonist treatment allows receptors to first become ubiquitinated and then deubiquitinated, thus, providing a 'trip switch' between degradative and recycling pathways at the late-endosomal compartments. Thus, USPs 20 and 33 serve as novel regulators that dictate both post-endocytic sorting as well as the intensity and extent of beta(2)AR signalling from the cell surface.

The overexpressed human 46-kDa mannose 6-phosphate receptor mediates endocytosis and sorting of. beta. -glucuronidase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watanabe, H.; Grubb, J.H.; Sly, W.S.

1990-10-01

The authors studied the function of the human small (46-kDa) mannose 6-phosphate receptor (SMPR) in transfected mouse L cells that do not express the larger insulin-like growth factor II/mannose 6-phosphate receptor. Cells overexpressing human SMPR were studied for enzyme binding to cell surface receptors, for binding to intracellular receptors in permeabilized cells, and for receptor-mediated endocytosis of recombinant human {beta}-glucuronidase. Specific binding to human SMPR in permeabilized cells showed a pH optimum between pH 6.0 and pH 6.5. Binding was significant in the present of EDTA but was enhanced by added divalent cations. Up to 2.3{percent} of the total functionalmore » receptor could be detected on the cell surface by enzyme binding. They present experiments showing that at very high levels of overexpression, and at pH 6.5, human SMPR mediated the endocytosis of {beta}-glucuronidase. At pH 7.5, the rate of endocytosis was only 14{percent} the rate seen at pH 6.5. Cells overexpressing human SMPR also showed reduced secretion of newly synthesized {beta}-glucuronidase when compared to cells transfected with vector only, suggesting that overexpressed human SMPR can participate in sorting of newly synthesized {beta}-glucuronidase and partially correct the sorting defect in mouse L cells that do not express the insulin-like growth factor II/mannose 6-phosphate receptor.« less

Comparison of osteoblast-like cell responses to calcium silicate and tricalcium phosphate ceramics in vitro.

PubMed

Ni, Siyu; Chang, Jiang; Chou, Lee; Zhai, Wanyin

2007-01-01

Calcium silicate ceramics have been proposed as new bone repair biomaterials, since they have proved to be bioactive, degradable, and biocompatible. Beta-tricalcium phosphate ceramic is a well-known degradable material for bone repair. This study compared the effects of CaSiO3 (alpha-, and beta-CaSiO3) and beta-Ca3(PO4)2 (beta-TCP) ceramics on the early stages of rat osteoblast-like cell attachment, proliferation, and differentiation. Osteoblast-like cells were cultured directly on CaSiO3 (alpha-, and beta-CaSiO3) and beta-TCP ceramics. Attachment of a greater number of cells was observed on CaSiO3 (alpha-, and beta-CaSiO3) ceramics compared with beta-TCP ceramics after incubation for 6 h. SEM observations showed an intimate contact between cells and the substrates, significant cells adhesion, and that the cells spread and grew on the surfaces of all the materials. In addition, the proliferation rate and alkaline phosphatase (ALP) activity of the cells on the CaSiO3 (alpha-, and beta-CaSiO3) ceramics were improved when compared with the beta-TCP ceramics. In the presence of CaSiO3, elevated levels of calcium and silicon in the culture medium were observed throughout the 7-day culture period. In conclusion, the results of the present study revealed that CaSiO3 ceramics showed greater ability to support cell attachment, proliferation, and differentiation than beta-TCP ceramic. 2006 Wiley Periodicals, Inc.

Proliferation of prostate cancer cells and activity of neutral endopeptidase is regulated by bombesin and IL-1beta with IL-1beta acting as a modulator of cellular differentiation.

PubMed

Albrecht, Martin; Doroszewicz, Jolanta; Gillen, Sonja; Gomes, Iara; Wilhelm, Beate; Stief, Thomas; Aumüller, Gerhard

2004-01-01

Neutral endopeptidase (NEP) is a cell-surface bound enzyme that cleaves and inactivates neuropeptides such as bombesin and substance P and is involved in the transition from hormonally regulated androgen-dependent prostate cancer (PC) to androgen-independent PC. Neuropeptides are implicated in growth regulation of different cell types and function as transmitters between the neuroendocrine and the immune system. NEP-expression, enzymatic activity of the membrane bound protein, cell proliferation, procalcitonin (PCT) production, and secretion as well as changes in cell morphology of prostatic cells were evaluated after treatment with the immunomodulatory cytokine interleukin-1beta (IL-1beta), neuropeptides (bombesin, substance P), and neuropeptide-conditioned media derived from a human neuroendocrine cell line. Incubation of LNCaP tumor cells with IL-1beta resulted in a diminished proliferative activity, induction of neurite-like outgrowth which was accompanied by the formation of tubular-type mitochondria typical for neuronal/neuroendocrine cells, and an increased production and secretion of PCT. Conversely, proliferation of prostatic stromal cells was enhanced by the cytokine coming along with an increased number of Golgi-apparatuses and ER-cisternae. Bombesin had an antimitotic effect on LNCaP, but not on stromal cells. Substance P did not influence the growth of any of the cell types investigated, whereas neuropeptide-conditioned media exerted a slightly mitogenic effect on both cell types. The activity of LNCaP cell-surface bound NEP was enhanced by bombesin, but was diminished by substance P and neuropeptide-conditioned media. Proliferation and activity of neuropeptide degrading NEP is regulated differently by immunomodulatory substances in PC cells and cells derived from the prostatic stroma with IL-1beta being a potent modulator of cellular differentiation and a potential target for anticancer drug design in PC cells. Copyright 2003 Wiley-Liss, Inc.

Generating hypoimmunogenic human embryonic stem cells by the disruption of beta 2-microglobulin.

PubMed

Lu, Pengfei; Chen, Jijun; He, Lixiazi; Ren, Jiangtao; Chen, Haide; Rao, Lingjun; Zhuang, Qinggang; Li, Hui; Li, Lei; Bao, Lei; He, Ji; Zhang, Wei; Zhu, Faming; Cui, Chun; Xiao, Lei

2013-12-01

Immune rejection hinders the application of human embryonic stem cells (hESCs) in transplantation therapy. Human leukocyte antigens (HLAs) on the cell surface are the major cause of graft rejection. In this study, we generated HLA class I-deficient hESCs via disruption of beta 2-microglobulin (β2m), the light chain of HLA Class I. We found that HLA class I proteins were not present on the cell surface of β2m-null hESCs. These cells showed the same pluripotency as wildtype hESCs and demonstrated hypoimmunogenicity. Thus, HLA class I-deficient hESCs might serve as an unlimited cell source for the generation of universally compatible "off-the-shelf" cell grafts, tissues or organs in the future.

Energy-driven surface evolution in beta-MnO2 structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yao, Wentao; Yuan, Yifei; Asayesh-Ardakani, Hasti

Exposed crystal facets directly affect the electrochemical/catalytic performance of MnO2 materials during their applications in supercapacitors, rechargeable batteries, and fuel cells. Currently, the facet-controlled synthesis of MnO2 is facing serious challenges due to the lack of an in-depth understanding of their surface evolution mechanisms. Here, combining aberration-corrected scanning transmission electron microscopy (STEM) and high-resolution TEM, we revealed a mutual energy-driven mechanism between beta-MnO2 nanowires and microstructures that dominated the evolution of the lateral facets in both structures. The evolution of the lateral surfaces followed the elimination of the {100} facets and increased the occupancy of {110} facets with the increasemore » in hydrothermal retention time. Both self-growth and oriented attachment along their {100} facets were observed as two different ways to reduce the surface energies of the beta-MnO2 structures. High-density screw dislocations with the 1/2 < 100 > Burgers vector were generated consequently. The observed surface evolution phenomenon offers guidance for the facet-controlled growth of beta-MnO2 materials with high performances for its application in metal-air batteries, fuel cells, supercapacitors, etc.« less

In vitro biological evaluation of beta-TCP/HDPE--A novel orthopedic composite: a survey using human osteoblast and fibroblast bone cells.

PubMed

Homaeigohar, S Sh; Shokrgozar, M A; Khavandi, A; Sadi, A Yari

2008-02-01

Beta-tricalcium phosphate reinforced high density polyethylene (beta-TCP/HDPE) was prepared to simulate bone composition and to study its capacity to act as bone tissue. This material was produced by replacing the mineral component and collagen soft tissue of the bone with beta-TCP and HDPE, respectively. The biocompatibility of the composite samples with different volume fractions of TCP (20, 30 and 40 vol %) was examined in vitro using two osteoblast cell lines G-292 and Saos-2, and also a type of fibroblast cell isolated from bone tissue, namely human bone fibroblast (HBF) by proliferation, and cell adhesion assays. Cell-material interaction with the surface of the composite samples was examined by scanning electron microscopy (SEM). The effect of beta-TCP/HDPE on the behavior of osteoblast and fibroblast cells was compared with those of composite and negative control samples; polyethylene (PE) and tissue culture polystyrene (TPS), respectively. In general, the results showed that the composite samples containing beta-TCP as reinforcement supported a higher rate of proliferation by various bone cells after 3, 7, and 14 days of incubation compared to the composite control sample. Furthermore, more osteoblast cells were attached to the surface of the composite samples when compared to the composite control samples after the above incubation periods (p < 0.05), while in the case of HBF an equal or even higher number of cells adhered to PE was observed. The number of adhered osteoblast cells was almost equal and in some days even higher than the number of adhered cells on negative control sample, while in the case of fibroblast this difference was significantly higher than TPS (p < 0.05). Adhered cells presented a normal morphology by SEM and many of the cells were observed to be undergoing cell division. These findings indicate that beta-TCP/HDPE composites are biocompatible, nontoxic, and act to stimulate proliferation and adhesion of the cells, whether osteoblast or fibroblast. (c) 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008.

TGF-beta1 secretion of ROS-17/2.8 cultures on NiTi implant material.

PubMed

Kapanen, Anita; Kinnunen, Anne; Ryhänen, Jorma; Tuukkanen, Juha

2002-08-01

The biocompatibility of an orthopedic implant depends on the effect of the implant on bone-forming cells, osteoblasts. Changes in osteoblastic proliferation, maturation and differentiation are important events in ossification that enable monitoring the effect of the implant. Transforming growth factor-beta (TGF-beta) is known to suppress osteoblast proliferation and, on the other hand, to induce the maturation and differentiation of osteoblasts. Moreover, osteoblasts produce TGF-beta, which is embedded in the bone matrix and activated by bone-resorbing osteoclasts. TGF-beta inhibits osteoclastic activity. Here, we show for the first time the effect of nickel titanium shape memory metal (NiTi) on osteoblastic cytokine expression. In this study, we measured the levels of TGF-beta with enzyme-linked immunosorbent assay (ELISA) from a ROS-17/2.8 osteosarcoma cell line cultured on different metal alloy discs. ELISA results were proportioned to total DNA content of the samples. We compared NiTi, to stainless steel (Stst), pure titanium (Ti) and pure nickel (Ni). The TGF-beta1/DNA value in the NiTi group (0.0007 +/- 0.0003) was comparable with those seen in the Stst (0.0008 +/- 0.0001) and Ti (0.0007 +/- 0.0001) groups. The concentration in the Ni group was lower (0.0006 +/- 0.0003), though not statistically significantly so. In addition, the effect of surface roughness on TGF-beta1 production was studied. We compared three different grades of roughness in three differently hot-rolled alloys: NiTi. hot-rolled at 950 degrees C. Ti alloy hot-rolled at 850 degrees C (TiI) and the same Ti alloy hot-rolled at 1,050 degrees C (TiII). We found that increasing roughness of the NiTi surface increased the TGF-beta1 concentration. On the other hand, all roughness groups of TiII showed low levels of TGF-beta1. while a rough TiI surface induced similar TGF-beta1, expression as rough NiTi. Further, these same measurements made with interleukine 6 (IL-6) were found to be under the detection limit in these cultures. We conclude that a rough NiTi surface promotes TGF-beta1 expression in ROS-17/2.8 cells.

Transduction of beta3 integrin subunit cDNA confers on human keratinocytes the ability to adhere to gelatin.

PubMed

Kubo, Miyoko; Clark, Richard A F; Katz, Anne B; Taichman, Lorne B; Jin, Zaishun; Zhao, Ying; Moriguchi, Takahiko

2007-04-01

alphavbeta3 is a multiligand integrin receptor that interacts with fibrinogen (FG), fibrin (FB), fibronectin (FN), vitronectin (VN), and denatured collagen. We previously reported that cultured normal human keratinocytes, like in vivo keratinocytes, do not express alphavbeta3 on the cell surface, and do not adhere to and migrate on FG and FB. Furthermore, we reported that human keratinocytes transduced with beta3 integrin subunit cDNA by a retrovirus-mediated transduction method express alphavbeta3 on the cell surface and adhere to FG, FB, FN, and VN significantly compared with beta-galactosidase (beta-gal) cDNA-transduced keratinocytes (control). In this study, we determined whether these beta3 integrin subunit cDNA-transduced keratinocytes or normal human keratinocytes adhere to denatured collagen (gelatin) using a 1 h cell adhesion assay. beta3 cDNA-transduced keratinocytes adhered to gelatin, whereas no significant adhesion was observed with the control cells (beta-gal cDNA-transduced keratinocytes and normal human keratinocytes). The adhesion to gelatin was inhibited by LM609, a monoclonal antibody to alphavbeta3, and RGD peptides but not by normal mouse IgG1 nor RGE peptides. Thus, transduction of beta3 integrin subunit cDNA confers on human keratinocytes the ability to adhere to denatured collagen (gelatin) as well as to FG, FB, VN, and FN. Otherwise, normal human keratinocytes do not adhere to gelatin. These data support the idea that beta3 cDNA-transduced human keratinocytes can be a good material for cultured epithelium to achieve better take rate with acute or chronic wounds, in which FG, FB, and denatured collagen are abundantly present.

Expression and in vitro regulation of integrins by normal human urothelial cells.

PubMed

Southgate, J; Kennedy, W; Hutton, K A; Trejdosiewicz, L K

1995-08-01

Integrins are thought to be essential adhesion receptors for the maintenance of tissue histioarchitecture. The purpose of this study was to determine integrin expression patterns in the human stratified transitional epithelium of the urinary tract (urothelium). In situ expression patterns were compared with in vitro expression, using a normal cell culture model system in which the effects of cell stratification can be studied independently of differentiation. By immunohistological criteria, the urothelia of bladder, ureter and renal pelvis expressed alpha 2 beta 1 and alpha 3 beta 1 integrins in all layers at intercellular junctions, and cytoplasmically in the lower strata. By contrast, alpha 6 beta 4 and occasionally alpha v beta 4 were expressed only by basal cells and localised to the basal lamina. These expression patterns were unaltered in specimens where an inflammatory cell infiltrate was present. In long-term cultures of normal urothelial cells maintained in a low-Ca++ serum-free medium, the monolayer cultures expressed alpha 2 beta 1, alpha 3 beta 1 and alpha 5 beta 1 integrins at intercellular junctions and in cytoplasmic inclusions, whereas alpha 6 beta 4 was distributed in a random pattern over the substratum. Increasing exogenous Ca++ concentrations induced cell stratification and desmosome formation, but not cytodifferentiation. Under these conditions, alpha 6 beta 4 became cell-, rather than substratum-associated, localising particularly to filopodia and lamellipodia. Quantitation of integrin expression by flow cytometry confirmed increased surface expression of alpha 6 beta 4 in high Ca++ media, and also of alpha 3 and alpha 5, but not alpha 2, subunits. These results suggest that alpha 2 beta 1 and alpha 3 beta 1 integrins, although differentially regulated, are mainly involved in homotypic cell-cell interactions and the maintenance of a stratified morphology, whereas alpha 6 beta 4 is the principal integrin involved in substratum adhesion.

A chitosan/beta-glycerophosphate thermo-sensitive gel for the delivery of ellagic acid for the treatment of brain cancer.

PubMed

Kim, Sungwoo; Nishimoto, Satoru K; Bumgardner, Joel D; Haggard, Warren O; Gaber, M Waleed; Yang, Yunzhi

2010-05-01

We report here the development of a chitosan/beta-glycerophosphate(Ch/beta-GP) thermo-sensitive gel to deliver ellagic acid (EA) for cancer treatment. The properties of the Ch/beta-GP gels were characterized regarding chemical structure, surface morphology, and viscoelasticity. In vitro EA release rate from the EA loaded Ch/beta-GP gel and chitosan degradation rate were investigated. The anti-tumor effect of the EA loaded Ch/beta-GP gel on brain cancer cells (human U87 glioblastomas and rat C6 glioma cells) was evaluated by examining cell viability. Cell number and activity were monitored by the MTS assay. The Ch/beta-GP solution formed a heat-induced gel at body temperature, and the gelation temperature and time were affected by the final pH of the Ch/beta-GP solution. The lysozyme increased the EA release rate by 2.5 times higher than that in the absence of lysozyme. Dialyzed chitosan solution with final pH 6.3 greatly reduced the beta-GP needed for gelation, thereby significantly improving the biocompatibility of gel (p < 0.001). The chitosan gels containing 1% (w/v) of ellagic acid significantly reduced viability of U87 cells and C6 cells compared with the chitosan gels at 3 days incubation (p < 0.01, and p < 0.001, respectively). Copyright 2010 Elsevier Ltd. All rights reserved.

Structural and biological mimicry of protein surface recognition by [alpha/beta]-peptide foldamers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Horne, W. Seth; Johnson, Lisa M.; Ketas, Thomas J.

Unnatural oligomers that can mimic protein surfaces offer a potentially useful strategy for blocking biomedically important protein-protein interactions. Here we evaluate an approach based on combining {alpha}- and {beta}-amino acid residues in the context of a polypeptide sequence from the HIV protein gp41, which represents an excellent testbed because of the wealth of available structural and biological information. We show that {alpha}/{beta}-peptides can mimic structural and functional properties of a critical gp41 subunit. Physical studies in solution, crystallographic data, and results from cell-fusion and virus-infectivity assays collectively indicate that the gp41-mimetic {alpha}/{beta}-peptides effectively block HIV-cell fusion via a mechanism comparablemore » to that of gp41-derived {alpha}-peptides. An optimized {alpha}/{beta}-peptide is far less susceptible to proteolytic degradation than is an analogous {alpha}-peptide. Our findings show how a two-stage design approach, in which sequence-based {alpha} {yields} {beta} replacements are followed by site-specific backbone rigidification, can lead to physical and biological mimicry of a natural biorecognition process.« less

Peptides and methods against diabetes

DOEpatents

Albertini, Richard J.; Falta, Michael T.

2000-01-01

This invention relates to methods of preventing or reducing the severity of diabetes. In one embodiment, the method involves administering to the individual a peptide having substantially the sequence of a on-conserved region sequence of a T cell receptor present on the surface of T cells mediating diabetes or a fragment thereof, wherein the peptide or fragment is capable of causing an effect on the immune system to regulate the T cells. In particular, the T cell receptor has the V.beta. regional V.beta.6 or V.beta.14. In another embodiment, the method involves gene therapy. The invention also relates to methods of diagnosing diabetes by determining the presence of diabetes predominant T cell receptors.

Translation and assembly of HLA-DR antigens in Xenopus oocytes injected with mRNA from a human B-cell line.

PubMed Central

Long, E O; Gross, N; Wake, C T; Mach, J P; Carrel, S; Accolla, R; Mach, B

1982-01-01

HLA-DR antigens are polymorphic cell surface glycoproteins, expressed primarily in B lymphocytes and macrophages, which are thought to play an important role in the immune response. Two polypeptide chains, alpha and beta, are associated at the cell surface, and a third chain associates with alpha and beta intracellularly. RNA isolated from the human B-cell line Raji was injected in Xenopus laevis oocytes. Immunoprecipitates of translation products with several monoclonal antibodies revealed the presence of HLA-DR antigens similar to those synthesized in Raji cells. One monoclonal antibody was able to bind the beta chain after dissociation of the three polypeptide chains with detergent. The presence of all three chains was confirmed by two-dimensional gel electrophoresis. The glycosylation pattern of the three chains was identical to that observed in vivo, as evidenced in studies using tunicamycin, an inhibitor of N-linked glycosylation. The presence of alpha chains assembled with beta chains in equimolar ratio was further demonstrated by amino-terminal sequencing. An RNA fraction enriched for the three mRNAs, encoding alpha, beta, and intracellular chains, was isolated. This translation-assembly system and the availability of monoclonal antibodies make it possible to assay for mRNA encoding specific molecules among the multiple human Ia-like antigens. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. PMID:6821356

Induction of myofibroblastic differentiation in vitro by covalently immobilized transforming growth factor-beta(1).

PubMed

Metzger, Wolfgang; Grenner, Nadine; Motsch, Sandra E; Strehlow, Rothin; Pohlemann, Tim; Oberringer, Martin

2007-11-01

Growth factors are an important tool in tissue engineering. Bone morphogenetic protein-2 and transforming growth factor-beta(1) (TGF-beta(1)) are used to provide bioactivity to surgical implants and tissue substitute materials. Mostly growth factors are used in soluble or adsorbed form. However, simple adsorption of proteins to surfaces is always accompanied by reduced stability and undefined pharmacokinetics. This study aims to prove that TGF-beta(1) can be covalently immobilized to functionalized surfaces, maintaining its ability to induce myofibroblastic differentiation of normal human dermal fibroblasts. In vivo, fibroblasts differentiate to myofibroblasts (MFs) during soft tissue healing by the action of TGF-beta(1). As surfaces for our experiments, we used slides bearing aldehyde, epoxy, or amino groups. For our in vitro cell culture experiments, we used the expression of alpha-smooth muscle actin as a marker for MFs after immunochemical staining. Using the aldehyde and the epoxy slides, we were able to demonstrate the activity of immobilized TGF-beta(1) through a significant increase in MF differentiation rate. A simple immunological test was established to detect TGF-beta(1) on the surfaces. This technology enables the creation of molecular "landscapes" consisting of several factors arranged in a distinct spatial pattern and immobilized on appropriate surfaces.

In vitro differentiation of rat bone marrow mesenchymal stem cells into hepatocytes.

PubMed

Feng, Zhihui; Li, Changying; Jiao, Shuxian; Hu, Bin; Zhao, Lin

2011-01-01

To investigate the mechanism and regulation of differentiation from bone marrow mesenchymal stem cells (BMSCs) into hepatocytes and to find a new source for therapies of hepatic diseases. We isolated BMSCs for subsequent differentiation in the presence of hepatocyte growth factor (HGF) or beta-nerve growth factor (beta-NGF). Cell morphology was observed and cell surface phenotypings were detected by flow cytometry. a1-antitrypsin (AAT) expression of the hepatocytes was confirmed by immunocytochemistry and albumin expression was validated by real time PCR and western blotting. The expression of high-affinity nerve growth factor receptor (TrkA) and the activation of Erk pathway were detected by western blotting. Hepatocyte functional activity was confirmed by uptake of indocyanine green (ICG) assay. Small round cells appeared in the presence of HGF on day 10 or beta-NGF on day 12. Differentiated cells expressed albumin and had functional characteristics of hepatocytes, such as uptake of ICG. BMSCs were positive for TrkA. HGF and beta-NGF significantly upregulated the protein levels of phospho-Erk. BMSCs could differentiate into hepatocytes in the differentiation media including HGF or beta-NGF. Combination of HGF and beta-NGF significantly increased the efficiency of hepatic differentiation.

Mechanisms of integrin-vascular endothelial growth factor receptor cross-activation in angiogenesis.

PubMed

Mahabeleshwar, Ganapati H; Feng, Weiyi; Reddy, Kumar; Plow, Edward F; Byzova, Tatiana V

2007-09-14

The functional responses of endothelial cells are dependent on signaling from peptide growth factors and the cellular adhesion receptors, integrins. These include cell adhesion, migration, and proliferation, which, in turn, are essential for more complex processes such as formation of the endothelial tube network during angiogenesis. This study identifies the molecular requirements for the cross-activation between beta3 integrin and tyrosine kinase receptor 2 for vascular endothelial growth factor (VEGF) receptor (VEGFR-2) on endothelium. The relationship between VEGFR-2 and beta3 integrin appears to be synergistic, because VEGFR-2 activation induces beta3 integrin tyrosine phosphorylation, which, in turn, is crucial for VEGF-induced tyrosine phosphorylation of VEGFR-2. We demonstrate here that adhesion- and growth factor-induced beta3 integrin tyrosine phosphorylation are directly mediated by c-Src. VEGF-stimulated recruitment and activation of c-Src and subsequent beta3 integrin tyrosine phosphorylation are critical for interaction between VEGFR-2 and beta3 integrin. Moreover, c-Src mediates growth factor-induced beta3 integrin activation, ligand binding, beta3 integrin-dependent cell adhesion, directional migration of endothelial cells, and initiation of angiogenic programming in endothelial cells. Thus, the present study determines the molecular mechanisms and consequences of the synergism between 2 cell surface receptor systems, growth factor receptor and integrins, and opens new avenues for the development of pro- and antiangiogenic strategies.

Beta3 subunits promote expression and nicotine-induced up-regulation of human nicotinic alpha6* nicotinic acetylcholine receptors expressed in transfected cell lines.

PubMed

Tumkosit, Prem; Kuryatov, Alexander; Luo, Jie; Lindstrom, Jon

2006-10-01

Nicotinic acetylcholine receptors (AChRs) containing alpha6 subunits are typically found at aminergic nerve endings where they play important roles in nicotine addiction and Parkinson's disease. alpha6* AChRs usually contain beta3 subunits. beta3 subunits are presumed to assemble only in the accessory subunit position within AChRs where they do not participate in forming acetylcholine binding sites. Assembly of subunits in the accessory position may be a critical final step in assembly of mature AChRs. Human alpha6 AChRs subtypes were permanently transfected into human tsA201 human embryonic kidney (HEK) cell lines. alpha6beta2beta3 and alpha6beta4beta3 cell lines were found to express much larger amounts of AChRs and were more sensitive to nicotine-induced increase in the amount of AChRs than were alpha6beta2 or alpha6beta4 cell lines. The increased sensitivity to nicotine-induced up-regulation was due not to a beta3-induced increase in affinity for nicotine but probably to a direct effect on assembly of AChR subunits. HEK cells express only a small amount of mature alpha6beta2 AChRs, but many of these subunits are on the cell surface. This contrasts with Xenopus laevis oocytes, which express a large amount of incorrectly assembled alpha6beta2 subunits that bind cholinergic ligands but form large amorphous intracellular aggregates. Monoclonal antibodies (mAbs) were made to the alpha6 and beta3 subunits to aid in the characterization of these AChRs. The alpha6 mAbs bind to epitopes C-terminal of the extracellular domain. These data demonstrate that both cell type and the accessory subunit beta3 can play important roles in alpha6* AChR expression, stability, and up-regulation by nicotine.

Probing transmembrane mechanical coupling and cytomechanics using magnetic twisting cytometry

NASA Technical Reports Server (NTRS)

Wang, N.; Ingber, D. E.

1995-01-01

We recently developed a magnetic twisting cytometry technique that allows us to apply controlled mechanical stresses to specific cell surface receptors using ligand-coated ferromagnetic microbeads and to simultaneously measure the mechanical response in living cells. Using this technique, we have previously shown the following: (i) beta 1 integrin receptors mediate mechanical force transfer across the cell surface and to the cytoskeleton, whereas other transmembrane receptors (e.g., scavenger receptors) do not; (ii) cytoskeletal stiffness increases in direct proportion to the level of stress applied to integrins; and (iii) the slope of this linear stiffening response differs depending on the shape of the cell. We now show that different integrins (beta 1, alpha V beta 3, alpha V, alpha 5, alpha 2) and other transmembrane receptors (scavenger receptor, platelet endothelial cell adhesion molecule) differ in their ability to mediate force transfer across the cell surface. In addition, the linear stiffening behavior previously observed in endothelial cells was found to be shared by other cell types. Finally, we demonstrate that dynamic changes in cell shape that occur during both cell spreading and retraction are accompanied by coordinate changes in cytoskeletal stiffness. Taken together, these results suggest that the magnetic twisting cytometry technique may be a powerful and versatile tool for studies analyzing the molecular basis of transmembrane mechanical coupling to the cytoskeleton as well as dynamic relations between changes in cytoskeletal structure and alterations in cell form and function.

Pin1 promotes transforming growth factor-beta-induced migration and invasion.

PubMed

Matsuura, Isao; Chiang, Keng-Nan; Lai, Chen-Yu; He, Dongming; Wang, Guannan; Ramkumar, Romila; Uchida, Takafumi; Ryo, Akihide; Lu, Kunping; Liu, Fang

2010-01-15

Transforming growth factor-beta (TGF-beta) regulates a wide variety of biological activities. It induces potent growth-inhibitory responses in normal cells but promotes migration and invasion of cancer cells. Smads mediate the TGF-beta responses. TGF-beta binding to the cell surface receptors leads to the phosphorylation of Smad2/3 in their C terminus as well as in the proline-rich linker region. The serine/threonine phosphorylation sites in the linker region are followed by the proline residue. Pin1, a peptidyl-prolyl cis/trans isomerase, recognizes phosphorylated serine/threonine-proline motifs. Here we show that Smad2/3 interacts with Pin1 in a TGF-beta-dependent manner. We further show that the phosphorylated threonine 179-proline motif in the Smad3 linker region is the major binding site for Pin1. Although epidermal growth factor also induces phosphorylation of threonine 179 and other residues in the Smad3 linker region the same as TGF-beta, Pin1 is unable to bind to the epidermal growth factor-stimulated Smad3. Further analysis suggests that phosphorylation of Smad3 in the C terminus is necessary for the interaction with Pin1. Depletion of Pin1 by small hairpin RNA does not significantly affect TGF-beta-induced growth-inhibitory responses and a number of TGF-beta/Smad target genes analyzed. In contrast, knockdown of Pin1 in human PC3 prostate cancer cells strongly inhibited TGF-beta-mediated migration and invasion. Accordingly, TGF-beta induction of N-cadherin, which plays an important role in migration and invasion, is markedly reduced when Pin1 is depleted in PC3 cells. Because Pin1 is overexpressed in many cancers, our findings highlight the importance of Pin1 in TGF-beta-induced migration and invasion of cancer cells.

Gene silencing of beta-catenin in melanoma cells retards their growth but promotes the formation of pulmonary metastasis in mice.

PubMed

Takahashi, Yuki; Nishikawa, Makiya; Suehara, Tetsuya; Takiguchi, Naomi; Takakura, Yoshinobu

2008-11-15

Altered expression of beta-catenin, a key component of the Wnt signaling pathway, is involved in a variety of cancers because increased levels of beta-catenin protein are frequently associated with enhanced cellular proliferation. Although our previous study demonstrated that gene silencing of beta-catenin in melanoma B16-BL6 cells by plasmid DNA (pDNA) expressing short-hairpin RNA targeting the gene (pshbeta-catenin) markedly suppressed their growth in vivo, gene silencing of beta-catenin could promote tumor metastasis by the rearranging cell adhesion complex. In this study, we investigated how silencing of beta-catenin affects metastatic aspects of melanoma cells. Transfection of B16-BL6 cells with pshbeta-catenin significantly reduced the amount of cadherin protein, a cell adhesion molecule binding to beta-catenin, with little change in its mRNA level. Cadherin-derived fragments were detected in culture media of B16-BL6 cells transfected with pshbeta-catenin, suggesting that cadherin is shed from the cell surface when the expression of beta-catenin is reduced. The mobility of B16-BL6 cells transfected with pshbeta-catenin was greater than that of cells transfected with any of the control pDNAs. B16-BL6 cells stably transfected with pshbeta-catenin (B16/pshbeta-catenin) formed less or an equal number of tumor nodules in the lung than cells stably transfected with other plasmids when injected into mice via the tail vein. However, when subcutaneously inoculated, B16/pshbeta-catenin cells formed more nodules in the lung than the other stably transfected cells. These results raise concerns about the gene silencing of beta-catenin for inhibiting tumor growth, because it promotes tumor metastasis by reducing the amount of cadherin in tumor cells. (c) 2008 Wiley-Liss, Inc.

Activation of antigen-specific cytotoxic T lymphocytes by beta 2-microglobulin or TAP1 gene disruption and the introduction of recipient-matched MHC class I gene in allogeneic embryonic stem cell-derived dendritic cells.

PubMed

Matsunaga, Yusuke; Fukuma, Daiki; Hirata, Shinya; Fukushima, Satoshi; Haruta, Miwa; Ikeda, Tokunori; Negishi, Izumi; Nishimura, Yasuharu; Senju, Satoru

2008-11-01

A method for the genetic modification of dendritic cells (DC) was previously established based on the in vitro differentiation of embryonic stem (ES) cells to DC (ES-DC). The unavailability of human ES cells genetically identical to the patients will be a problem in the future clinical application of this technology. This study attempted to establish a strategy to overcome this issue. The TAP1 or beta(2)-microglobulin (beta(2)m) gene was disrupted in 129 (H-2(b))-derived ES cells and then expression vectors for the H-2K(d) or beta(2)m-linked form of K(d) (beta2m-K(d)) were introduced, thus resulting in two types of genetically engineered ES-DC, TAP1(-/-)/K(d) ES-DC and beta(2)m(-/-)/beta(2)m-K(d) ES-DC. As intended, both of the transfectant ES-DC expressed K(d) but not the intrinsic H-2(b) haplotype-derived MHC class I. Beta(2)m(-/-)/beta(2)m-K(d) and TAP1(-/-)/K(d) ES-DC were not recognized by pre-activated H-2(b)-reactive CTL and did not prime H-2(b) reactive CTL in vitro or in vivo. Beta(2)m(-/-)/beta(2)m-K(d) ES-DC and TAP1(-/-)/K(d) ES-DC had a survival advantage in comparison to beta(2)m(+/-)/beta(2)m-K(d) ES-DC and TAP1(+/+)/K(d) ES-DC, when transferred into BALB/c mice. K(d)-restricted RSV-M2-derived peptide-loaded ES-DC could prime the epitope-specific CTL upon injection into the BALB/c mice, irrespective of the cell surface expression of intrinsic H-2(b) haplotype-encoded MHC class I. Beta(2)m(-/-)/beta(2)m-K(d) ES-DC were significantly more efficient in eliciting immunity against RSV M2 protein-expressing tumor cells than beta(2)m(+/-)/beta(2)m-K(d) ES-DC. The modification of the beta(2)m or TAP gene may therefore be an effective strategy to resolve the problem of HLA class I allele mismatch between human ES or induced pluripotent stem cells and the recipients to be treated.

Comparative analysis of cell wall surface glycan expression in Candida albicans and Saccharomyces cerevisiae yeasts by flow cytometry.

PubMed

Martínez-Esparza, M; Sarazin, A; Jouy, N; Poulain, D; Jouault, T

2006-07-31

The yeast Candida albicans is an opportunistic pathogen, part of the normal human microbial flora that causes infections in immunocompromised individuals with a high morbidity and mortality levels. Recognition of yeasts by host cells is based on components of the yeast cell wall, which are considered part of its virulence attributes. Cell wall glycans play an important role in the continuous interchange that regulates the balance between saprophytism and parasitism, and also between resistance and infection. Some of these molecular entities are expressed both by the pathogenic yeast C. albicans and by Saccharomyces cerevisiae, a related non-pathogenic yeast, involving similar molecular mechanisms and receptors for recognition. In this work we have exploited flow cytometry methods for probing surface glycans of the yeasts. We compared glycan expression by C. albicans and by S. cerevisiae, and studied the effect of culture conditions. Our results show that the expression levels of alpha- and beta-linked mannosides as well as beta-glucans can be successfully evaluated by flow cytometry methods using different antibodies independent of agglutination reactions. We also found that the surface expression pattern of beta-mannosides detected by monoclonal or polyclonal antibodies are differently modulated during the growth course. These data indicate that the yeast beta-mannosides exposed on mannoproteins and/or phospholipomannan are increased in stationary phase, whereas those linked to mannan are not affected by the yeast growth phase. The cytometric method described here represents a useful tool to investigate to what extent C. albicans is able to regulate its glycan surface expression and therefore modify its virulence properties.

Use of a purified and functional recombinant calcium-channel beta4 subunit in surface-plasmon resonance studies.

PubMed Central

Geib, Sandrine; Sandoz, Guillaume; Mabrouk, Kamel; Matavel, Alessandra; Marchot, Pascale; Hoshi, Toshinori; Villaz, Michel; Ronjat, Michel; Miquelis, Raymond; Lévêque, Christian; de Waard, Michel

2002-01-01

Native high-voltage-gated calcium channels are multi-subunit complexes comprising a pore-forming subunit Ca(v) and at least two auxiliary subunits alpha(2)delta and beta. The beta subunit facilitates cell-surface expression of the channel and contributes significantly to its biophysical properties. In spite of its importance, detailed structural and functional studies are hampered by the limited availability of native beta subunit. Here, we report the purification of a recombinant calcium-channel beta(4) subunit from bacterial extracts by using a polyhistidine tag. The purified protein is fully functional since it binds on the alpha1 interaction domain, its main Ca(v)-binding site, and regulates the activity of P/Q calcium channel expressed in Xenopus oocytes in a similar way to the beta(4) subunit produced by cRNA injection. We took advantage of the functionality of the purified material to (i) develop an efficient surface-plasmon resonance assay of the interaction between two calcium channel subunits and (ii) measure, for the first time, the affinity of the recombinant His-beta(4) subunit for the full-length Ca(v)2.1 channel. The availability of this purified material and the development of a surface-plasmon resonance assay opens two immediate research perspectives: (i) drug screening programmes applied to the Ca(v)/beta interaction and (ii) crystallographic studies of the calcium-channel beta(4) subunit. PMID:11988102

Deficiency of bone marrow beta3-integrin enhances non-functional neovascularization.

PubMed

Watson, Alan R; Pitchford, Simon C; Reynolds, Louise E; Direkze, Natalie; Brittan, Mairi; Alison, Malcolm R; Rankin, Sara; Wright, Nicholas A; Hodivala-Dilke, Kairbaan M

2010-03-01

beta3-Integrin is a cell surface adhesion and signalling molecule important in the regulation of tumour angiogenesis. Mice with a global deficiency in beta3-integrin show increased pathological angiogenesis, most likely due to increased vascular endothelial growth factor receptor 2 expression on beta3-null endothelial cells. Here we transplanted beta3-null bone marrow (BM) into wild-type (WT) mice to dissect the role of BM beta3-integrin deficiency in pathological angiogenesis. Mice transplanted with beta3-null bone marrow show significantly enhanced angiogenesis in subcutaneous B16F0 melanoma and Lewis lung carcinoma (LLC) cell models and in B16F0 melanoma lung metastasis when compared with tumours grown in mice transplanted with WT bone marrow. The effect of bone marrow beta3-integrin deficiency was also assessed in the RIPTAg mouse model of pancreatic tumour growth. Again, angiogenesis in mice lacking BM beta3-integrin was enhanced. However, tumour weight between the groups was not significantly altered, suggesting that the enhanced blood vessel density in the mice transplanted with beta3-null bone marrow was not functional. Indeed, we demonstrate that in mice transplanted with beta3-null bone marrow a significant proportion of tumour blood vessels are non-functional when compared with tumour blood vessels in WT-transplanted controls. Furthermore, beta3-null-transplanted mice showed an increased angiogenic response to VEGF in vivo when compared with WT-transplanted animals. BM beta3-integrin deficiency affects the mobilization of progenitor cells to the peripheral circulation. We show that VEGF-induced mobilization of endothelial progenitor cells is enhanced in mice transplanted with beta3-null bone marrow when compared with WT-transplanted controls, suggesting a possible mechanism underlying the increased blood vessel density seen in beta3-null-transplanted mice. In conclusion, although BM beta3-integrin is not required for pathological angiogenesis, our studies demonstrate a role for BM beta3-integrin in VEGF-induced mobilization of bone marrow-derived cells to the peripheral circulation and for the functionality of those vessels in which BM-derived cells become incorporated.

Soybean beta-conglycinin peptone suppresses food intake and gastric emptying by increasing plasma cholecystokinin levels in rats.

PubMed

Nishi, Takashi; Hara, Hiroshi; Tomita, Fusao

2003-02-01

Cholecystokinin (CCK) is an important physiologic mediator that regulates satiety and gastric emptying. We demonstrated previously that soybean peptone acts directly on rat small intestinal mucosal cells to stimulate CCK release. In the present study, we examined the effects of beta-conglycinin, a major component of soy protein, and its peptone on food intake and gastric emptying after an intraduodenal infusion of beta-conglycinin peptone in relation to CCK release and interaction with the mucosal cell membrane. Intraduodenal infusion of beta-conglycinin peptone inhibited food intake in a dose-dependent manner, but that of whole soy peptone or camostat did not. The suppression of food intake by beta-conglycinin peptone was abolished by an intravenous injection of devazepide, a selective peripheral CCK receptor antagonist. The beta-conglycinin peptone infusion strongly suppressed gastric emptying with marked increases in portal CCK levels. We also observed that the beta-conglycinin peptone dose dependently and more potently stimulated CCK release from isolated dispersed mucosal cells of the rat jejunum than did beta-conglycinin itself. This stimulation corresponded to the binding activity of the peptide or protein to solubilized components of the rat jejunum membrane as evaluated by surface plasmon biosensor. These results indicate that beta-conglycinin peptone suppresses food intake, and this effect may be due to beta-conglycinin peptone in the lumen stimulating endogenous CCK release with direct acceptance to the intestinal cells.

The Synthesis of N-Acetyllactosamine Functionalized Dendrimers, and the Functionalization of Silica Surfaces Using Tunable Dendrons and beta-Cyclodextrins

NASA Astrophysics Data System (ADS)

Ennist, Jessica Helen

Galectin-3 is beta-galactoside binding protein which is found in many healthy cells. In cancer, the galectin-3/tumor-associated Thomsen-Friedenreich antigen (TF antigen) interaction has been implicated in heterotypic and homotypic cellular adhesion and apoptotic signaling pathways. However, a stronger mechanistic understanding of the role of galectin-3 in these processes is needed. N-acetyllactosamine (LacNAc) is a non-native ligand for galectin-3 which binds with comparable affinity to the TF antigen and therefore an important ligand to study galectin-3 mediated processes. To study galectin-3 mediated homotypic cellular aggregation, four generations of polyamidoamine (PAMAM) dendrimers were functionalized with N-acetyllactosamine using a four-step chemoenzymatic route. The enzymatic step controlled the regiochemistry of the galactose addition to N-acetylglucosamine functionalized dendrimers using a recombinant beta-1,4-Galactosyltransferase-/UDP-4'-Gal Epimerase Fusion Protein (lgtB-galE). Homotypic cellular aggregation, which is promoted by the presence of galectin-3 as it binds to glycosides at the cell surface, was studied using HT-1080 fibrosarcoma, A549 lung, and DU-145 prostate cancer cell lines. In the presence of small LacNAc functionalized PAMAM dendrimers, galectin-3 induced cancer cellular aggregation was inhibited. However, the larger glycodendrimers induced homotypic cellular aggregation. Additionally, novel poly(aryl ether) dendronized silica surfaces designed for reversible adsorbtion of targeted analytes were synthesized, and characterization using X-ray Photoelectron Spectroscopy (XPS) was performed. Using a Cu(I) mediated cycloaddition "click" reaction, beta-cyclodextrin was appended to dendronized surfaces via triazole formation and also to a non-dendronized surface for comparison purposes. First generation G(1) dendrons have more than 6 times greater capacity to adsorb targeted analytes than slides functionalized with monomeric beta-cyclodextrin and are 2 times greater than slides functionalized with larger generation dendrons. This study reported beta-cyclodextrin functionalized surfaces can undergo a triggered release of the adsorbent, but otherwise retained the targeted analyte through multiple aqueous washes. Therefore, a new generation of G(1) dendronized surfaces capable of reversible adsorption were developed by heterogeneously appending sulfonic acid/pyridine end-groups. Auger Electron Spectroscopy (AES) was used to quantify the ratio of groups installed. Furthermore, G(1) dendronized surfaces were functionalized homogenously with sulfonic acid and pyridine for comparison and with chiral amino acids for chiral recognition studies.

Nanoscale organization of {beta}{sub 2}-adrenergic receptor-Venus fusion protein domains on the surface of mammalian cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vobornik, Dusan; Rouleau, Yanouchka; Haley, Jennifer

2009-04-24

Adrenergic receptors are a key component of nanoscale multiprotein complexes that are responsible for controlling the beat rate in a mammalian heart. We demonstrate the ability of near-field scanning optical microscopy (NSOM) to visualize {beta}{sub 2}-adrenergic receptors ({beta}{sub 2}AR) fused to the GFP analogue Venus at the nanoscale on HEK293 cells. The expression of the {beta}{sub 2}AR-Venus fusion protein was tightly controlled using a tetracycline-induced promoter. Both the size and density of the observed nanoscale domains are dependent on the level of induction and thus the level of protein expression. At concentrations between 100 and 700 ng/ml of inducer doxycycline,more » the size of domains containing the {beta}{sub 2}AR-Venus fusion protein appears to remain roughly constant, but the number of domains per cell increase. At 700 ng/ml doxycycline the functional receptors are organized into domains with an average diameter of 150 nm with a density similar to that observed for the native protein on primary murine cells. By contrast, larger micron-sized domains of {beta}{sub 2}AR are observed in the membrane of the HEK293 cells that stably overexpress {beta}{sub 2}AR-GFP and {beta}{sub 2}AR-eYFP. We conclude that precise chemical control of gene expression is highly advantageous for the use {beta}{sub 2}AR-Venus fusion proteins as models for {beta}{sub 2}AR function. These observations are critical for designing future cell models and assays based on {beta}{sub 2}AR, since the receptor biology is consistent with a relatively low density of nanoscale receptor domains.« less

Anti-Angiogenic Action of Neutral Endopeptidase

DTIC Science & Technology

2006-11-01

natriuretic factor, substance P , bradykinin, oxytocin, Leu- and Met-enkephalins, neurotensin, bombesin, endothelin-1 (ET-1), and beta amyloid. Loss...NOTES 14. ABSTRACT: Please see attached. 15. SUBJECT TERMS Angiogenesis, Cell surface peptidase , Neutral endopeptidase, Basic fibroblast growth...effective therapies for patients with prostate cancer. Cell-surface peptidases are the guardians of the cell against small stimulatory peptides

Live Candida albicans suppresses production of reactive oxygen species in phagocytes.

PubMed

Wellington, Melanie; Dolan, Kristy; Krysan, Damian J

2009-01-01

Production of reactive oxygen species (ROS) is an important aspect of phagocyte-mediated host responses. Since phagocytes play a crucial role in the host response to Candida albicans, we examined the ability of Candida to modulate phagocyte ROS production. ROS production was measured in the murine macrophage cell line J774 and in primary phagocytes using luminol-enhanced chemiluminescence. J774 cells, murine polymorphonuclear leukocytes (PMN), human monocytes, and human PMN treated with live C. albicans produced significantly less ROS than phagocytes treated with heat-killed C. albicans. Live C. albicans also suppressed ROS production in murine bone marrow-derived macrophages from C57BL/6 mice, but not from BALB/c mice. Live C. albicans also suppressed ROS in response to external stimuli. C. albicans and Candida glabrata suppressed ROS production by phagocytes, whereas Saccharomyces cerevisiae stimulated ROS production. The cell wall is the initial point of contact between Candida and phagocytes, but isolated cell walls from both heat-killed and live C. albicans stimulated ROS production. Heat-killed C. albicans has increased surface exposure of 1,3-beta-glucan, a cell wall component that can stimulate phagocytes. To determine whether surface 1,3-beta-glucan exposure accounted for the difference in ROS production, live C. albicans cells were treated with a sublethal dose of caspofungin to increase surface 1,3-beta-glucan exposure. Caspofungin-treated C. albicans was fully able to suppress ROS production, indicating that suppression of ROS overrides stimulatory signals from 1,3-beta-glucan. These studies indicate that live C. albicans actively suppresses ROS production in phagocytes in vitro, which may represent an important immune evasion mechanism.

Diverse roles of integrin receptors in articular cartilage.

PubMed

Shakibaei, M; Csaki, C; Mobasheri, A

2008-01-01

Integrins are heterodimeric integral membrane proteins made up of alpha and beta subunits. At least eighteen alpha and eight beta subunit genes have been described in mammals. Integrin family members are plasma membrane receptors involved in cell adhesion and active as intra- and extracellular signalling molecules in a variety of processes including embryogenesis, hemostasis, tissue repair, immune response and metastatic spread of tumour cells. Integrin beta 1 (beta1-integrin), the protein encoded by the ITGB1 gene (also known as CD29 and VLAB), is a multi-functional protein involved in cell-matrix adhesion, cell signalling, cellular defense, cell adhesion, protein binding, protein heterodimerisation and receptor-mediated activity. It is highly expressed in the human body (17.4 times higher than the average gene in the last updated revision of the human genome). The extracellular matrix (ECM) of articular cartilage is a unique environment. Interactions between chondrocytes and the ECM regulate many biological processes important to homeostasis and repair of articular cartilage, including cell attachment, growth, differentiation and survival. The beta1-integrin family of cell surface receptors appears to play a major role in mediating cell-matrix interactions that are important in regulating these fundamental processes. Chondrocyte mechanoreceptors have been proposed to incorporate beta1-integrins and mechanosensitive ion channels which link with key ECM, cytoskeletal and signalling proteins to maintain the chondrocyte phenotype, prevent chondrocyte apoptosis and regulate chondrocyte-specific gene expression. This review focuses on the expression and function of beta1-integrins in articular chondrocytes, its role in the unique biology of these cells and its distribution in cartilage.

Radiation leukemia virus-induced thymic lymphomas express a restricted repertoire of T-cell receptor V beta gene products.

PubMed Central

Sen-Majumdar, A; Weissman, I L; Hansteen, G; Marian, J; Waller, E K; Lieberman, M

1994-01-01

We have investigated the phenotypic changes that take place during the process of neoplastic transformation in the thymocytes of C57BL/Ka mice infected by the radiation leukemia virus (RadLV). By the combined use of antibodies against the envelope glycoprotein gp70 of RadLV, the transformation-associated cell surface marker 1C11, and the CD3-T-cell receptor (TCR) complex, we found that in the RadLV-infected thymus, the earliest expression of viral gp70 is in 1C11hi cells; a small but significant percentage of these cells also express CD3. A first wave of viral replication, manifested by the expression of high levels of gp70 in thymocytes (over 70% positive), reaches a peak at 2 weeks; during this period, no significant changes are observed in the expression of 1C11 or CD3. The population of gp70+ cells is drastically reduced at 3 to 4 weeks after infection. However, a second cohort of gp70+ cells appears after 4 weeks, and these cells express high levels of 1C11 and TCR determinants as well. RadLV-induced lymphomas differ from normal thymocytes in their CD4 CD8 phenotype, with domination by one or more subsets. Characterization of TCR gene rearrangements in RadLV-induced lymphomas shows that most of these tumors are clonal or oligoclonal with respect to the J beta 2 TCR gene, while the J beta 1 TCR gene is rearranged in a minority (4 of 11) of lymphomas. TCR V beta repertoire analysis of 12 tumors reveals that 6 (50%) express exclusively the V beta 6 gene product, 2 (17%) are V beta 5+, and 1 (8%) each are V beta 8+ and V beta 9+. In normal C57BL/Ka mice, V beta 6 is expressed on 12%, V beta 5 is expressed on 9%, V beta 8 is expressed on 22%, and V beta 9 is expressed on 4% of TCRhi thymocytes. Thus, it appears that RadLV-induced thymic lymphomas are not randomly selected with respect to expressed TCR V beta type. Images PMID:8289345

Dystroglycan loss disrupts polarity and beta-casein induction inmammary epithelial cells by perturbing laminin anchoring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weir, M. Lynn; Oppizzi, Maria Luisa; Henry, Michael D.

2006-02-17

Precise contact between epithelial cells and their underlying basement membrane is critical to the maintenance of tissue architecture and function. To understand the role that the laminin receptor dystroglycan (DG) plays in these processes, we assayed cell responses to laminin-111 following conditional ablation of DG expression in cultured mammary epithelial cells (MECs). Strikingly, DG loss disrupted laminin-111-induced polarity and {beta}-casein production, and abolished laminin assembly at the step of laminin binding to the cell surface. DG re-expression restored these deficiencies. Investigations of mechanism revealed that DG cytoplasmic sequences were not necessary for laminin assembly and signaling, and only when themore » entire mucin domain of extracellular DG was deleted did laminin assembly not occur. These results demonstrate that DG is essential as a laminin-111 co-receptor in MECs that functions by mediating laminin anchoring to the cell surface, a process that allows laminin polymerization, tissue polarity, and {beta}-casein induction. The observed loss of laminin-111 assembly and signaling in DG-/-MECs provides insights into the signaling changes occurring in breast carcinomas and other cancers, where DG's laminin-binding function is frequently defective.« less

Functional relationship between cationic amino acid transporters and beta-defensins: implications for dry skin diseases and the dry eye.

PubMed

Jäger, Kristin; Garreis, Fabian; Posa, Andreas; Dunse, Matthias; Paulsen, Friedrich P

2010-04-20

The ocular surface, constantly exposed to environmental pathogens, is particularly vulnerable to infection. Hence an advanced immune defence system is essential to protect the eye from microbial attack. Antimicrobial peptides, such as beta-defensins, are essential components of the innate immune system and are the first line of defence against invaders of the eye. High concentrations of L-arginine and L-lysine are necessary for the expression of beta-defensins. These are supplied by epithelial cells in inflammatory processes. The limiting factor for initiation of beta-defensin production is the transport of L-arginine and L-lysine into the cell. This transport is performed to 80% by only one transporter system in the human, the y(+)-transporter. This group of proteins exclusively transports the cationic amino acids L-arginine, L-lysine and L-ornithine and is also known under the term cationic amino acid transporter proteins (CAT-proteins). Various infections associated with L-arginine deficiency (for example psoriasis, keratoconjuctivitis sicca) are also associated with an increase in beta-defensin production. For the first time, preliminary work has shown the expression of human CATs in ocular surface epithelia and tissues of the lacrimal apparatus indicating their relevance for diseases of the ocular surface. In this review, we summarize current knowledge on the human CATs that appear to be integrated in causal regulation cascades of beta-defensins, thereby offering novel concepts for therapeutic perspectives. Copyright 2010 Elsevier GmbH. All rights reserved.

Epidermal differentiation during ontogeny and after hatching in the snake Liasis fuscus (Pythonidae, Serpentes, Reptilia), with emphasis on the formation of the shedding complex.

PubMed

Alibardi, L; Thompson, M B

2003-04-01

Differentiation and localization of keratin in the epidermis during embryonic development and up to 3 months posthatching in the Australian water python, Liasis fuscus, was studied by ultrastructural and immunocytochemical methods. Scales arise from dome-like folds in the skin that produce tightly imbricating scales. The dermis of these scales is completely differentiated before any epidermal differentiation begins, with a loose dermis made of mesenchymal cells beneath the differentiating outer scale surface. At this stage (33) the embryo is still unpigmented and two layers of suprabasal cells contain abundant glycogen. At Stage 34 (beginning of pigmentation) the first layers of cells beneath the bilayered periderm (presumptive clear and oberhautchen layers) have not yet formed a shedding complex, within which prehatching shedding takes place. At Stage 35 the shedding complex, consisting of the clear and oberhautchen layers, is discernible. The clear layer contains a fine fibrous network that faces the underlying oberhautchen, where the spinulae initially contain a core of fibrous material and small beta-keratin packets. Differentiation continues at Stage 36 when the beta-layer forms and beta-keratin packets are deposited both on the fibrous core of the oberhautchen and within beta-cells. Mesos cells are produced from the germinal layer but remain undifferentiated. At Stage 37, before hatching, the beta-layer is compact, the mesos layer contains mesos granules, and cells of the alpha-layer are present but are not yet keratinized. They are still only partially differentiated a few hours after hatching, when a new shedding complex is forming underneath. Using antibodies against chick scale beta-keratin resolved at high magnification with immunofluorescent or immunogold conjugates, we offer the first molecular confirmation that in snakes only the oberhautchen component of the shedding complex and the underlying beta cells contain beta-keratin. Initially, there is little immunoreactivity in the small beta-packets of the oberhautchen, but it increases after fusion with the underlying cells to produce the syncytial beta layer. The beta-keratin packets coalesce with the tonofilaments, including those attached to desmosomes, which rapidly disappear in both oberhautchen and beta-cells as differentiation progresses. The labeling is low to absent in forming mesos-cells beneath the beta-layer. This study further supports the hypothesis that the shedding complex in lepidosaurian reptiles evolved after there was a segregation between alpha-keratogenic cells from beta-keratogenic cells during epidermal renewal. Copyright 2003 Wiley-Liss, Inc.

The role of alpha3beta1 integrin in determining the supramolecular organization of laminin-5 in the extracellular matrix of keratinocytes.

PubMed

deHart, Gregory W; Healy, Kevin E; Jones, Jonathan C R

2003-02-01

Analyses of mice with targeted deletions in the genes for alpha3 and beta1 integrin suggest that the alpha3beta1 integrin heterodimer likely determines the organization of the extracellular matrix within the basement membrane of skin. Here we tested this hypothesis using keratinocytes derived from alpha3 integrin-null mice. We have compared the organizational state of laminin-5, a ligand of alpha3beta1 integrin, in the matrix of wild-type keratinocytes with that of laminin-5 in the matrix of alpha3 integrin-null cells. Laminin-5 distributes diffusely in arc structures in the matrix of wild-type mouse keratinocytes, whereas laminin-5 is organized into linear, spike-like arrays by the alpha3 integrin-null cells. The fact that alpha3 integrin-null cells are deficient in their ability to assemble a proper laminin-5 matrix is also shown by their failure to remodel laminin-5 when plated onto surfaces coated with purified laminin-5 protein. In sharp contrast, wild-type keratinocytes organize exogenously added laminin-5 into discrete ring-like organizations. These findings led us next to assess whether differences in laminin-5 organization in the matrix of the wild-type and alpha3 integrin-null cells impact cell behavior. Our results indicate that alpha3 integrin-null cells are more motile than their wild-type counterparts and leave extensive trails of laminin-5 over the surface on which they move. Moreover, HEK 293 cells migrate significantly more on the laminin-5-rich matrix derived from the alpha3 integrin-null cells than on the wild-type keratinocyte laminin-5 matrix. In addition, alpha3 integrin-null cells show low strength of adhesion to surfaces coated with purified laminin-5 compared to wild-type cells although both the wild type and the alpha3 integrin-null keratinocytes adhere equally strongly to laminin-5 that has been organized into arrays by other epithelial cells. These data suggest: (1) that alpha3beta1 integrin plays an important role in determining the incorporation of laminin-5 into its proper higher-order structure within the extracellular matrix of keratinocytes and (2) that the organizational state of laminin-5 has an influence on laminin-5 matrix function. Copyright 2003 Elsevier Science (USA)

Characterization of interactions between Nedd4 and beta and gammaENaC using surface plasmon resonance.

PubMed

Asher, C; Chigaev, A; Garty, H

2001-09-07

Cell surface expression of the epithelial Na(+) channel ENaC is regulated by the ubiquitin ligase Nedd4. Binding of the WW domains of Nedd4 to the PY region in the carboxy tails of beta and gammaENaC, results in channel ubiquitination and degradation. Kinetic analysis of these interactions has been done using surface plasmon resonance. Synthetic peptides corresponding to the PY regions of beta and gammaENaC were immobilized on a sensor chip and "real-time" kinetics of their binding to recombinant WW proteins was determined. Specificity of the interactions was established by competition experiment, as well as by monitoring effects of a point mutation known to impair Nedd4/ENaC binding. These data provides the first determination of association, dissociation and equilibrium constants for the interactions between WW2 and beta or gammaENaC. Copyright 2001 Academic Press.

Disruption of alpha beta but not of gamma delta T cell development by overexpression of the helix-loop-helix protein Id3 in committed T cell progenitors.

PubMed Central

Blom, B; Heemskerk, M H; Verschuren, M C; van Dongen, J J; Stegmann, A P; Bakker, A Q; Couwenberg, F; Res, P C; Spits, H

1999-01-01

Enforced expression of Id3, which has the capacity to inhibit many basic helix-loop-helix (bHLH) transcription factors, in human CD34(+) hematopoietic progenitor cells that have not undergone T cell receptor (TCR) gene rearrangements inhibits development of the transduced cells into TCRalpha beta and gamma delta cells in a fetal thymic organ culture (FTOC). Here we document that overexpression of Id3, in progenitors that have initiated TCR gene rearrangements (pre-T cells), inhibits development into TCRalpha beta but not into TCRgamma delta T cells. Furthermore, Id3 impedes expression of recombination activating genes and downregulates pre-Talpha mRNA. These observations suggest possible mechanisms by which Id3 overexpression can differentially affect development of pre-T cells into TCRalpha beta and gamma delta cells. We also observed that cell surface CD4(-)CD8(-)CD3(-) cells with rearranged TCR genes developed from Id3-transduced but not from control-transduced pre-T cells in an FTOC. These cells had properties of both natural killer (NK) and pre-T cells. These findings suggest that bHLH factors are required to control T cell development after the T/NK developmental checkpoint. PMID:10329625

Beta-Adrenergic Receptor Population is Up-Regulated in Chicken Skeletal Muscle Cells Treated with Forskolin

NASA Technical Reports Server (NTRS)

Bridge, K. Y.; Young, R. B.; Vaughn, J. R.

1998-01-01

Skeletal muscle hypertrophy is promoted by in vivo administration of beta-adrenergic receptor (betaAR) agonists. These compounds presumably exert their physiological action through the betaAR, and alterations in the population of betaAR could potentially change the ability of the cell to respond to the betaAR agonists. Since the intracellular chemical signal generated by the betaAR is cyclic AMP (cAMP), experiments were initiated in primary chicken muscle cell cultures to determine if artificial elevation of intracellular cAMP by treatment with forskolin would alter the population of functional betaAR expressed on the surface of muscle cells. Chicken skeletal muscle cells after 7 days in culture were employed for the experiments because muscle cells have attained a steady state with respect to muscle protein metabolism at this stage. Cells were treated with 0-10 microM forskolin for a total of three days. At the end of the 1, 2, and 3 day treatment intervals, the concentration of cAMP and the betaAR population were measured. Receptor population was measured in intact muscle cell cultures as the difference between total binding of [H-3]CGP-12177 and non-specific binding of [H-3]CGP-12177 in the presence of 1 microM propranolol. Intracellular cAMP concentration was measured by radioimmunoassay. The concentration of cAMP in forskolin-treated cells increased up to 10-fold in a dose dependent manner. Increasing concentrations of forskolin also led to an increase in betaAR population, with a maximum increase of approximately 50% at 10 microM. This increase in PAR population was apparent after only 1 day of treatment, and the pattern of increase was maintained for all 3 days of the treatment period. Thus, increasing the intracellular concentration of cAMP leads to up-regulation of betaAR population. The effect of forskolin on the quantity and apparent synthesis rate of the heavy chain of myosin (mhc) were also investigated. A maximum increase of 50% in the quantity of mhc was observed at 0.2 microM forskolin, but higher concentrations of forskolin reduced the quantity of mhc back to control levels.

Transglutaminase 2 is needed for the formation of an efficient phagocyte portal in macrophages engulfing apoptotic cells.

PubMed

Tóth, Beáta; Garabuczi, Eva; Sarang, Zsolt; Vereb, György; Vámosi, György; Aeschlimann, Daniel; Blaskó, Bernadett; Bécsi, Bálint; Erdõdi, Ferenc; Lacy-Hulbert, Adam; Zhang, Ailiang; Falasca, Laura; Birge, Raymond B; Balajthy, Zoltán; Melino, Gerry; Fésüs, László; Szondy, Zsuzsa

2009-02-15

Transglutaminase 2 (TG2), a protein cross-linking enzyme with many additional biological functions, acts as coreceptor for integrin beta(3). We have previously shown that TG2(-/-) mice develop an age-dependent autoimmunity due to defective in vivo clearance of apoptotic cells. Here we report that TG2 on the cell surface and in guanine nucleotide-bound form promotes phagocytosis. Besides being a binding partner for integrin beta(3), a receptor known to mediate the uptake of apoptotic cells via activating Rac1, we also show that TG2 binds MFG-E8 (milk fat globulin EGF factor 8), a protein known to bridge integrin beta(3) to apoptotic cells. Finally, we report that in wild-type macrophages one or two engulfing portals are formed during phagocytosis of apoptotic cells that are characterized by accumulation of integrin beta(3) and Rac1. In the absence of TG2, integrin beta(3) cannot properly recognize the apoptotic cells, is not accumulated in the phagocytic cup, and its signaling is impaired. As a result, the formation of the engulfing portals, as well as the portals formed, is much less efficient. We propose that TG2 has a novel function to stabilize efficient phagocytic portals.

[Localization of 17 beta-hydroxysteroid dehydrogenase in the gonads of bivalve mollusks--the sea pecten (Patinopecten yessoensis Jay) and Gray's mussel (Crenomytilus grayanus Dunker)].

PubMed

Varaksina, G S; Varaksin, A A

1988-11-01

Presence of 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) in testes and ovaries of the common mussels--Patinopecten yessoensis (Jay) and Crenomytilus grayanus (Dunker) has been demonstrated histochemically. The enzyme is revealed in some granular amebocytes and germ cells. In growing oocytes its activity is higher that in oocytes completed their growth. 17 beta-HSD is revealed electron microscopically near agranular endoplasmic reticulum, or on the external surface of its membranes and in globules, possessing, evidently, lipid nature. The data obtained demonstrate that synthesis and metabolism of steroid hormones are possible both in additional gonadal elements and in germ cells of the animals investigated.

The low density lipoprotein receptor-related protein 1B retains beta-amyloid precursor protein at the cell surface and reduces amyloid-beta peptide production.

PubMed

Cam, Judy A; Zerbinatti, Celina V; Knisely, Jane M; Hecimovic, Silva; Li, Yonghe; Bu, Guojun

2004-07-09

The low density lipoprotein (LDL) receptor-related protein 1B (LRP1B) is a newly identified member of the LDL receptor family that shares high homology with the LDL receptor-related protein (LRP). LRP1B was originally described as a putative tumor suppressor in lung cancer cells; however, its expression profile in several regions of adult human brain suggests it may have additional functions in the central nervous system. Since LRP1B has overlapping ligand binding properties with LRP, we investigated whether LRP1B, like LRP, could interact with the beta-amyloid precursor protein (APP) and modulate its processing to amyloid-beta peptides (Abetas). Using an LRP1B minireceptor (mLRP1B4) generated to study the trafficking of LRP1B, we found that mLRP1B4 and APP form an immunoprecipitable complex. Furthermore mLRP1B4 bound and facilitated the degradation of a soluble isoform of APP containing a Kunitz proteinase inhibitor domain but not soluble APP lacking a Kunitz proteinase inhibitor domain. A functional consequence of mLRP1B4 expression was a significant accumulation of APP at the cell surface, which is likely related to the slow endocytosis rate of LRP1B. More importantly, mLRP1B4-expressing cells that accumulated cell surface APP produced less Abeta and secreted more soluble APP. These findings reveal that LRP1B is a novel binding partner of APP that functions to decrease APP processing to Abeta. Consequently LRP1B expression could function to protect against the pathogenesis of Alzheimer's disease.

Transduction of cultured fish cells with recombinant baculoviruses.

PubMed

Leisy, Douglas J; Lewis, Teresa D; Leong, Jo-Ann C; Rohrmann, George F

2003-05-01

Five fish cell lines were tested for their ability to be transduced by Ac-CAlacZ, a recombinant baculovirus that is capable of expressing a beta-galactosidase reporter gene from the CAG promoter (consisting of a cytomegalovirus enhancer element, a chicken actin promoter and rabbit beta-globin termination sequences). TO (Tilapia ovary), EPC (carp), CHH-1 (Chum salmon heart fibroblast) and CHSE-214 (chinook salmon embryo) cells were transducible, as demonstrated by an in situ beta-galactosidase assay, whereas RTG-2 (rainbow trout gonad) cells were not. The EPC cell line was used for more detailed studies on baculovirus transduction. The transduction frequency was found to be higher at 28 degrees C than at 21 degrees C. Addition of the histone deacetylase inhibitor sodium butyrate increased the number of blue cells detected 5- to 7-fold. The m.o.i. was positively correlated with transduction frequency, although the relationship did not appear to be strictly linear, as has been observed with mammalian cells. The temperature at which baculoviruses were adsorbed to EPC cells did not affect levels of beta-galactosidase expression. We also examined expression levels of beta-galactosidase in EPC cells after infection with a baculovirus construct that overexpresses the vesicular stomatitis virus G protein and displays it on the virion surface. Expression levels with this virus were approximately 15-fold higher than were observed with Ac-CAlacZ.

Rapid endocytosis of the low density lipoprotein receptor-related protein modulates cell surface distribution and processing of the beta-amyloid precursor protein.

PubMed

Cam, Judy A; Zerbinatti, Celina V; Li, Yonghe; Bu, Guojun

2005-04-15

The low density lipoprotein receptor-related protein (LRP) is a approximately 600-kDa multifunctional endocytic receptor that is highly expressed in the brain. LRP and its ligands apolipoprotein E, alpha2-macroglobulin, and beta-amyloid precursor protein (APP), are genetically linked to Alzheimer disease and are found in characteristic plaque deposits in brains of patients with Alzheimer disease. To identify which extracellular domains of LRP interact with APP, we used minireceptors of each of the individual LRP ligand binding domains and assessed their ability to bind and degrade a soluble APP fragment. LRP minireceptors containing ligand binding domains II and IV, but not I or III, interacted with APP. To test whether APP trafficking is directly related to the rapid endocytosis of LRP, we generated stable Chinese hamster ovary cell lines expressing either a wild-type LRP minireceptor or its endocytosis mutants. Chinese hamster ovary cells stably expressing wild-type LRP minireceptor had less cell surface APP than pcDNA3 vector-transfected cells, whereas those stably expressing endocytosis-defective LRP minireceptors accumulated APP at the cell surface. We also found that the steady-state levels of the amyloid beta-peptides (Abeta) is dictated by the relative expression levels of APP and LRP, probably reflecting the dual roles of LRP in both Abeta production and clearance. Together, these data establish a relationship between LRP rapid endocytosis and APP trafficking and proteolytic processing to generate Abeta.

Control of yeast mating signal transduction by a mammalian. beta. sub 2 -adrenergic receptor and G sub s. alpha. subunit

DOE Office of Scientific and Technical Information (OSTI.GOV)

King, K.; Caron, M.G.; Lefkowitz, R.J.

1990-10-05

To facilitate functional and mechanistic studies of receptor-G protein interactions by expression of the human {beta}{sub 2}-adrenergic receptor (h{beta}-AR) has been expressed in Saccharomyces cerevisiae. This was achieved by placing a modified h{beta}-AR gene under control of the galactose-inducible GAL1 promoter. After induction by galactose, functional h{beta}-AR was expressed at a concentration several hundred times as great as that found in any human tissue. As determined from competitive ligand binding experiments, h{beta}-AR expressed in yeast displayed characteristic affinities, specificity, and stereoselectivity. Partial activation of the yeast pheromone response pathway by {beta}-adrenergic receptor agonists was achieved in cells coexpressing h{beta}-AR andmore » a mammalian G protein (G{sub s}) {alpha} subunit - demonstrating that these components can couple to each other and to downstream effectors when expressed in yeast. This in vivo reconstitution system provides a new approach for examining ligand binding and G protein coupling to cell surface receptors.« less

Fibronectin-mediation cell adhesion is required for induction of 92-kDa type IV collagenase/gelatinase (MMP-9) gene expression during macrophage differentiation : the signaling role of protein kinase C-{beta}.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xie, B.; Laouar, A.; Huberman, E.

1998-05-08

Induction of the 92-kDa gelatinase (MMP-9) gene expression is associated with macrophage differentiation. In this study, we explored the regulatory mechanisms underlying this differentiation-associated MMP-9 gene expression in human HL-60 myeloid leukemia cells and human peripheral blood monocytes. Phorbol 12-myristate 13-acetate (PMA) markedly induced MMP-9 gene expression in HL-60 cells; the induction closely paralleled the timing and extent of PMA-induced cell adhesion and spreading, a hallmark of macrophage differentiation. Similarly, treatment with PMA or macrophage-colony stimulating factor stimulated adherence and spreading of blood monocytes with a concurrent 7- or 5-fold increase in MMP-9 production, respectively. In protein kinase C (PKC)-betamore » -deficient HL-60 variant cells (HL-525), PMA failed to induce cell adhesion and MMP-9 gene expression. Transfecting HL-525 cells with a PKC-beta expression plasmid restored PKC-beta levels and PMA inducibility of cell adhesion and spreading as well as MMP-9 gene expression. Induction of cell adhesion and MMP-9 gene expression in HL-60 cells and blood monocytes was strongly inhibited by neutralizing monoclonal antibodies to fibronectin (FN) and its receptor {alpha}5{beta}1 integrin. HL-525 cells, which constitutively display high levels of surface {alpha}5{beta}1 integrin, adhered and spread on immobilized FN with concomitant induction of MMP-9 gene expression. Cytochalasins B and D were each a potent inhibitor of MMP-9 production. Our results suggest that {alpha}5{beta}1 integrin-mediated interaction of immature hematopoietic cells with FN plays a critical role in modulating matrix-degrading activities during macrophage differentiation.« less

Slot-coupled CW standing wave accelerating cavity

DOEpatents

Wang, Shaoheng; Rimmer, Robert; Wang, Haipeng

2017-05-16

A slot-coupled CW standing wave multi-cell accelerating cavity. To achieve high efficiency graded beta acceleration, each cell in the multi-cell cavity may include different cell lengths. Alternatively, to achieve high efficiency with acceleration for particles with beta equal to 1, each cell in the multi-cell cavity may include the same cell design. Coupling between the cells is achieved with a plurality of axially aligned kidney-shaped slots on the wall between cells. The slot-coupling method makes the design very compact. The shape of the cell, including the slots and the cone, are optimized to maximize the power efficiency and minimize the peak power density on the surface. The slots are non-resonant, thereby enabling shorter slots and less power loss.

Localization of Alpha-Keratin and Beta-Keratin (Corneous Beta Protein) in the Epithelium on the Ventral Surface of the Lingual Apex and Its Lingual Nail in the Domestic Goose (Anser Anser f. domestica) by Using Immunohistochemistry and Raman Microspectroscopy Analysis.

PubMed

Skieresz-Szewczyk, Kinga; Jackowiak, Hanna; Buchwald, Tomasz; Szybowicz, Mirosław

2017-08-01

The epithelium of the ventral surface of the apex of the tongue in most birds is specified by the presence of the special superficial layer called lingual nail. The aim of the present study is to determine the localization of the alpha-keratin and beta-keratin (corneous beta protein) in this special epithelium in the domestic goose by using immunohistochemistry staining and the Raman spectroscopy analysis. Due to lack of commercially available antibodies to detect beta-keratin (corneous beta protein), the Raman spectroscopy was used as a specific tool to detect and describe the secondary structure of proteins. The immunohistochemical (IHC) detections reveal the presence of alpha-keratin in all layers of the epithelium, but significant differences in the distribution of the alpha-keratin in the epithelial layers appear. The staining reaction is stronger from the basal layer to the upper zone of the intermediate layer. The unique result is weak staining for the alpha-keratin in the lingual nail. Applications of the Raman spectroscopy as a complementary method not only confirmed results of IHC staining for alpha-keratin, but showed that this technique could be used to demonstrate the presence of beta-keratin (corneous beta protein). Functionally, the localization of alpha-keratin in the epithelium of the ventral surface of the lingual apex provides a proper scaffold for epithelial cells and promotes structural integrity, whereas the presence of beta-keratin (corneous beta protein) in the lingual nail, described also as exoskeleton of the ventral surface of the apex, endures mechanical stress. Anat Rec, 300:1361-1368, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Neutrophil chemotaxis in response to TGF-beta isoforms (TGF-beta 1, TGF-beta 2, TGF-beta 3) is mediated by fibronectin.

PubMed

Parekh, T; Saxena, B; Reibman, J; Cronstein, B N; Gold, L I

1994-03-01

TGF-beta isoforms regulate numerous cellular functions including cell growth and differentiation, the cellular synthesis and secretion of extracellular matrix proteins, such as fibronectin (Fn), and the immune response. We have previously shown that TGF-beta 1 is the most potent chemoattractant described for human peripheral blood neutrophils (PMNs), suggesting that TGF-beta s may play a role in the recruitment of PMNs during the initial phase of the inflammatory response. In our current studies, we demonstrate that the maximal chemotactic response was attained near 40 fM for all mammalian TGF-beta isoforms. However, there was a statistically significant difference in migratory distance of the PMNs: TGF-beta 2 (556 microM) > TGF-beta 3 (463 microM) > TGF-beta 1 (380 microM) (beta 2: beta 3, p < or = 0.010; beta 3: beta 1, p < or = 0.04; beta 2: beta 1, p < or = 0.0012). A mAb to the cell binding domain (CBD) of Fn inhibited the chemotactic response to TGF-beta 1 and TGF-beta 3 by 63% and to TGF-beta 2 by 70%, whereas the response to FMLP, a classic chemoattractant, was only inhibited by 18%. In contrast, a mAb to a C-terminal epitope of Fn did not retard migration (< 1.5%). The Arg-gly-Asp-ser tetrapeptide inhibited chemotaxis by approximately the same extent as the anti-CBD (52 to 83%). Furthermore, a mAb against the VLA-5 integrin (VLA-5; Fn receptor) also inhibited TGF-beta-induced chemotaxis. These results indicate that chemotaxis of PMNs in response to TGF-beta isoforms is mediated by the interaction of the Arg-gly-Asp-ser sequence in the CBD of Fn with an integrin on the PMN cell surface, primarily the VLA-5 integrin. TGF-beta isoforms also elicited the release of cellular Fn from PMNs; we observed a 2.3-fold increase in Fn (389 to 401 ng/ml) in the supernatants of TGF-beta-stimulated PMNs compared with unstimulated cells (173.6 ng/ml). The concentration of TGF-beta required to cause maximal release of Fn from PMNs (4000 fM) is a concentration at which TGF-beta is no longer chemotactic, suggesting that PMNs only use Fn that is constitutively expressed for migration. At higher concentrations of TGF-beta, the Fn released may accumulate basal to the cell, ultimately retarding cellular migration and modulating the chemotactic response.

Downregulation of cell surface molecules during noncytopathic infection of T cells with human immunodeficiency virus.

PubMed Central

Stevenson, M; Zhang, X H; Volsky, D J

1987-01-01

Noncytopathic infection of human T-lymphoid cell line CR-10 with human immunodeficiency virus (HIV) (CEM-N1T isolate) resulted in a gradual loss of cell surface receptors for OKT4/OKT4A (HIV receptor), OKT8, OKT3, and OKT11 but not for OKT9 (transferrin receptor) within 10 days after infection. Surface receptor decline was accompanied by a rapid increase in HIV antigens and mRNA expression. Multireceptor downregulation was also observed in three T-lymphoid cell lines (MT-4, CEM, and HBD-1) cytopathically infected with the HIV/N1T virus and in HUT-78 cells infected with the HIV/SF-2 isolate. HIV-infected and uninfected CR-10 cells contained similar levels of mRNAs coding for T3, T8, T9, T11, HLA-A2, and HLA-B7 proteins. By densitometry, fully infected CR-10 cells showed approximately 75% reduction in T4 and tubulin (beta chain) mRNA levels when compared with uninfected CR-10 cells. No such reduction was detected in HIV-infected MT-4 and HBD-1 cells. A T-cell receptor gene (beta chain) rearrangement study revealed that no distinct CR-10 subpopulation was selected out upon infection with HIV. Our results suggest that the reduction in cell surface receptors observed between 1 and 2 weeks postinfection cannot be directly attributed to similar reductions in mRNA levels coding for these receptor proteins. We conclude that HIV infection induces posttranscriptional downregulation of several T-cell surface receptors. Images PMID:3500327

Cutaneous beta human papillomaviruses and the development of male external genital lesions: A case-control study nested within the HIM Study.

PubMed

Pierce Campbell, Christine M; Gheit, Tarik; Tommasino, Massimo; Lin, Hui-Yi; Torres, B Nelson; Messina, Jane L; Stoler, Mark H; Rollison, Dana E; Sirak, Bradley A; Abrahamsen, Martha; Carvalho da Silva, Roberto J; Sichero, Laura; Villa, Luisa L; Lazcano-Ponce, Eduardo; Giuliano, Anna R

2016-10-01

Cutaneous human papillomaviruses (HPVs) increase the risk of non-melanoma skin cancer in sun-exposed skin. We examined the role of beta-HPV in the development of male external genital lesions (EGLs), a sun-unexposed site. In this nested case-control study (67 men with pathologically-confirmed EGLs and 134 controls), exfoliated cells collected from the surface of lesions and normal genital skin 0, 6, and 12 months preceding EGL development were tested for beta-HPV DNA using a type-specific multiplex genotyping assay. Beta-HPV prevalence was estimated and conditional logistic regression was used to evaluate the association with condyloma, the most common EGL. While beta-HPV prevalence among controls remained stable, the prevalence among cases was lowest on the surface of lesion. Detecting beta-HPV on the normal genital skin was not associated with the presence or development of condyloma. Cutaneous beta-HPV does not appear to be contributing to pathogenesis in male genital skin. Copyright © 2016. Published by Elsevier Inc.

Anchorage mediated by integrin alpha6beta4 to laminin 5 (epiligrin) regulates tyrosine phosphorylation of a membrane-associated 80-kD protein

PubMed Central

1996-01-01

Detachment of basal keratinocytes from basement membrane signals a differentiation cascade. Two integrin receptors alpha6beta4 and alpha3beta1 mediate adhesion to laminin 5 (epiligrin), a major extracellular matrix protein in the basement membrane of epidermis. By establishing a low temperature adhesion system at 4 degrees C, we were able to examine the exclusive role of alpha6beta4 in adhesion of human foreskin keratinocyte (HFK) and the colon carcinoma cell LS123. We identified a novel 80-kD membrane-associated protein (p80) that is tyrosine phosphorylated in response to dissociation of alpha6beta4 from laminin 5. The specificity of p80 phosphorylation for laminin 5 and alpha6beta4 was illustrated by the lack of regulation of p80 phosphorylation on collagen, fibronectin, or poly-L-lysine surfaces. We showed that blocking of alpha3beta1 function using inhibitory mAbs, low temperature, or cytochalasin D diminished tyrosine phosphorylation of focal adhesion kinase but not p80 phosphorylation. Therefore, under our assay conditions, p80 phosphorylation is regulated by alpha6beta4, while motility via alpha3beta1 causes phosphorylation of focal adhesion kinase. Consistent with a linkage between p80 dephosphorylation and alpha6beta4 anchorage to laminin 5, we found that phosphatase inhibitor sodium vanadate, which blocked the p80 dephosphorylation, prevented the alpha6beta4-dependent cell anchorage to laminin 5 at 4degreesC. In contrast, adhesion at 37 degrees C via alpha3beta1 was unaffected. Furthermore, by in vitro kinase assay, we identified a kinase activity for p80 phosphorylation in suspended HFKs but not in attached cells. The kinase activity, alpha6beta4, and its associated adhesion structure stable anchoring contacts were all cofractionated in the Triton- insoluble cell fraction that lacks alpha3beta1. Thus, regulation of p80 phosphorylation, through the activities of p80 kinase and phosphatase, correlates with alpha6beta4-SAC anchorage to laminin 5 at 4 degrees C in epithelial cells of the skin and intestine. Transmembrane signaling through p80 is an early tyrosine phosphorylation event responsive to and possibly required for anchorage to laminin 5 by HFK and LS123 epithelial cells. PMID:8647901

Dissecting the role of matrix metalloproteinases (MMP) and integrin alpha(v)beta3 in angiogenesis in vitro: absence of hemopexin C domain bioactivity, but membrane-Type 1-MMP and alpha(v)beta3 are critical.

PubMed

Nisato, Riccardo E; Hosseini, Ghamartaj; Sirrenberg, Christian; Butler, Georgina S; Crabbe, Thomas; Docherty, Andrew J P; Wiesner, Matthias; Murphy, Gillian; Overall, Christopher M; Goodman, Simon L; Pepper, Michael S

2005-10-15

Matrix metalloproteinase (MMP)-2 and its hemopexin C domain autolytic fragment (also called PEX) have been proposed to be crucial for angiogenesis. Here, we have investigated the dependency of in vitro angiogenesis on MMP-mediated extracellular proteolysis and integrin alpha(v)beta3-mediated cell adhesion in a three-dimensional collagen I model. The hydroxamate-based synthetic inhibitors BB94, CT1399, and CT1847 inhibited endothelial cell invasion, as did neutralizing anti-membrane-type 1-MMP (MT1-MMP) antibodies and tissue inhibitor of MMP (TIMP)-2 and TIMP-3 but not TIMP-1. This confirmed the pivotal importance of MT1-MMP over other MMPs in this model. Invasion was also inhibited by a nonpeptidic antagonist of integrin alpha(v)beta3, EMD 361276. Although PEX strongly inhibited pro-MMP-2 activation, when contaminating lipopolysaccharide was neutralized, PEX neither affected angiogenesis nor bound integrin alpha(v)beta(3). Moreover, no specific binding of pro-MMP-2 to integrin alpha(v)beta3 was found, whereas only one out of four independently prepared enzymatically active MMP-2 preparations could bind integrin alpha(v)beta3 , and this in a PEX-independent manner. Likewise, integrin alpha(v)beta3 -expressing cells did not bind MMP-2-coated surfaces. Hence, these findings show that endothelial cell invasion of collagen I gels is MT1-MMP and alpha(v)beta3 - dependent but MMP-2 independent and does not support a role for PEX in alpha(v)beta3 integrin binding or in modulating angiogenesis in this system.

Estradiol coupling to human monocyte nitric oxide release is dependent on intracellular calcium transients: evidence for an estrogen surface receptor.

PubMed

Stefano, G B; Prevot, V; Beauvillain, J C; Fimiani, C; Welters, I; Cadet, P; Breton, C; Pestel, J; Salzet, M; Bilfinger, T V

1999-10-01

We tested the hypothesis that estrogen acutely stimulates constitutive NO synthase (cNOS) activity in human peripheral monocytes by acting on an estrogen surface receptor. NO release was measured in real time with an amperometric probe. 17beta-estradiol exposure to monocytes stimulated NO release within seconds in a concentration-dependent manner, whereas 17alpha-estradiol had no effect. 17beta-estradiol conjugated to BSA (E2-BSA) also stimulated NO release, suggesting mediation by a membrane surface receptor. Tamoxifen, an estrogen receptor inhibitor, antagonized the action of both 17beta-estradiol and E2-BSA, whereas ICI 182,780, a selective inhibitor of the nuclear estrogen receptor, had no effect. We further showed, using a dual emission microfluorometry in a calcium-free medium, that the 17beta-estradiol-stimulated release of monocyte NO was dependent on the initial stimulation of intracellular calcium transients in a tamoxifen-sensitive process. Leeching out the intracellular calcium stores abolished the effect of 17beta-estradiol on NO release. RT-PCR analysis of RNA obtained from the cells revealed a strong estrogen receptor-alpha amplification signal and a weak beta signal. Taken together, a physiological dose of estrogen acutely stimulates NO release from human monocytes via the activation of an estrogen surface receptor that is coupled to increases in intracellular calcium.

Differential expression of extracellular matrix molecules and the alpha 6-integrins in the normal and neoplastic prostate.

PubMed Central

Knox, J. D.; Cress, A. E.; Clark, V.; Manriquez, L.; Affinito, K. S.; Dalkin, B. L.; Nagle, R. B.

1994-01-01

The epithelial basal lamina composition and integrin expression profile of normal and neoplastic human prostate was characterized using immunohistochemical analysis of frozen samples. The major components of the basal lamina surrounding normal acini were laminin, type IV collagen, entactin, and type VII collagen with variable amounts of tenascin. The basal lamina of neoplastic acini had a similar composition, except for the loss of type VII collagen, which was observed in all grades of carcinoma. The basal cells of the normal prostate express the alpha 6-, beta 1-, and beta 4-integrin subunits, suggesting that both the alpha 6 beta 1- and alpha 6 beta 4-integrin complexes are formed. In prostate carcinoma there is a complete loss of beta 4 expression and the alpha 6- and beta 1-integrin subunits, which are restricted to the basal and basal lateral surfaces of basal cells, are distributed diffusely throughout the cytoplasmic membrane. The differential expression of type VII collagen and beta 4 are discussed in relationship to their possible role in tumor progression. Images Figure 1 Figure 2 Figure 3 PMID:8030747

Regulation of the membrane mucin Muc4 in corneal epithelial cells by proteosomal degradation and TGF-beta.

PubMed

Lomako, Joseph; Lomako, Wieslawa M; Carothers Carraway, Coralie A; Carraway, Kermit L

2010-04-01

MUC4 is a heterodimeric membrane mucin, composed of a mucin subunit ASGP-1 (MUC4alpha) and a transmembrane subunit ASGP-2 (MUC4beta), which has been implicated in the protection of epithelial cell surfaces. In the rat stratified corneal epithelium Muc4 is found predominantly in the most superficial cell layers. Since previous studies in other tissues have shown that Muc4 is regulated by TGF-beta via a proteosomal degradation mechanism, we investigated the regulation of corneal Muc4 in stratified cultures of corneal epithelial cells. Application of proteosome or processing inhibitors led to increases in levels of Muc4, particularly in the basal and intermediate levels of the stratified cultures. These changes were accompanied by increases in Muc4 ubiquitination, chaperone association and incorporation into intracellular aggresomes. In contrast, treatment with TGF-beta resulted in reduced levels of Muc4, which were reversed by proteosome inhibition. The results support a model in which Muc4 precursor is synthesized in all layers of the corneal epithelium, but Muc4 is degraded in basal and intermediate layers by a proteosomal mechanism at least partly dependent on TGF-beta inhibition of Muc4 processing. J. Cell. Physiol. 223: 209-214, 2010. (c) 2009 Wiley-Liss, Inc.

Depletion of CD8+ cells in human thymic medulla results in selective immune deficiency

PubMed Central

1989-01-01

CD8 molecules expressed on the surface of a subset of T cells participate in the selection of class I MHC antigen-restricted T cells in the thymus, and in MHC-restricted immune responses of mature class I MHC antigen-restricted T cells. Here we describe an immune-deficient patient with lack of CD8+ peripheral blood cells. The patient presented with Pneumocystis carinii pneumonia and was unable to reject an allogeneic skin graft, but had normal primary and secondary antibody responses. Examination of the patient's thymus revealed that the loss of CD8+ cells occurred during intrathymic differentiation: the patient's immature cortical thymocytes included both CD4+ and CD8+ cells while the mature medullary cells expressed the CD4 but not the CD8 protein on their surface. Northern blot and polymerase chain reaction analyses revealed the presence of CD8 alpha and beta mRNA in the patient's thymus but not in the peripheral blood. Both class I MHC antigen expression and the expressed TCR V beta repertoire are normal in this patient. These data are consistent with an impaired selection of CD8+ cells in the patient's thymus and support the role of the CD8 surface protein in thymic selection previously characterized in genetically manipulated and inbred mice. PMID:2511270

The transplantation of neural stem cells and predictive factors in hematopoietic recovery in irradiated mice.

PubMed

Filip, S; Mokrý, J; Karbanová, J; Vávrová, J; Vokurková, J; Bláha, M; English, D

2005-04-01

A number of surprising observations have shown that stem cells, in suitable conditions, have the ability to produce a whole spectrum of cell types, regardless, whether these tissues are derived from the same germ layer or not. This phenomenon is called stem cell plasticity, which means that tissue-specific stem cells are mutually interchangeable. In our experiments, as a model, we used neural stem cells (NSCs) harvested from fetal (E14-15) neocortex and beta-galactosidase positive. In the first experiment we found that on days 12 and 30 after sub-lethal irradiation (LD 8.5 Gy) and (beta-galactosidase(+)) NSCs transplantation all mice survived, just as the group with bone marrow transplantation. Moreover, the bone marrow of mice transplanted NSCs contained the number of CFU-GM colonies with beta-galactosidase(+) cells which was as much as 50% higher. These differences were statistically significant, p<0.001. In the second experiment, we studied kinetics of (beta-galactosidase(+)) NSCs after their transplantation to sub-lethally irradiated mice. Histochemistry of tissues was performed on days 12 and 30 post-transplantation, and beta-galactosidase(+) cells were detected with the help of histochemical examination of removed tissues (lung, liver, spleen, thymus, and skeletal muscle). In tissues removed on day 12 post-transplantation, we found a significantly higher number of beta-galactosidase(+) cells in the spleen and thymus on day 30. While we presumed the presence beta-galactosidase(+) cells in the spleen, as spleen and reticuloendothelial system represent an important retaining system for different cell types, the presence of beta-galactosidase(+) cells in the thymus was rather surprising but very interesting. This indicates a certain mutual and close interconnection of transplanted stem cells and immune system in an adult organism. In the third experiment, we verified the mutual interchange of Sca-1 surface antigen in the bone marrow cells and NSCs before transplantation. Analysis of this antigen showed 24.8% Sca-1 positive cells among the bone marrow cells, while NSCs were Sca-1 negative. Our experiments show that NSCs share hemopoietic identity and may significantly influence the recovery of damaged hematopoiesis but do not have typical superficial markers as HSCs. This result is important for the determination of predictive factors for hemopoiesis recovery, for stem cell plasticity and for their use in the cell therapy.

Regulation of cytokine receptors by Golgi N-glycan processing and endocytosis.

PubMed

Partridge, Emily A; Le Roy, Christine; Di Guglielmo, Gianni M; Pawling, Judy; Cheung, Pam; Granovsky, Maria; Nabi, Ivan R; Wrana, Jeffrey L; Dennis, James W

2004-10-01

The Golgi enzyme beta1,6 N-acetylglucosaminyltransferase V (Mgat5) is up-regulated in carcinomas and promotes the substitution of N-glycan with poly N-acetyllactosamine, the preferred ligand for galectin-3 (Gal-3). Here, we report that expression of Mgat5 sensitized mouse cells to multiple cytokines. Gal-3 cross-linked Mgat5-modified N-glycans on epidermal growth factor and transforming growth factor-beta receptors at the cell surface and delayed their removal by constitutive endocytosis. Mgat5 expression in mammary carcinoma was rate limiting for cytokine signaling and consequently for epithelial-mesenchymal transition, cell motility, and tumor metastasis. Mgat5 also promoted cytokine-mediated leukocyte signaling, phagocytosis, and extravasation in vivo. Thus, conditional regulation of N-glycan processing drives synchronous modification of cytokine receptors, which balances their surface retention against loss via endocytosis.

Function of beta 2-adrenergic receptors in chronic localized myalgia.

PubMed

Maekawa, Kenji; Kuboki, Takuo; Inoue, Eitoku; Inoue-Minakuchi, Mami; Suzuki, Koji; Yatani, Hirofumi; Clark, Glenn T

2003-01-01

To investigate alteration of beta 2-adrenergic receptor (beta 2 AR) function in chronic localized myalgia subjects by evaluating levels of the beta 2 AR second messenger, cyclic adenosine monophosphate (cAMP), in mononuclear cells after beta AR-agonist stimulation. Eleven chronic localized myalgia subjects and 21 matched healthy controls participated in this study. Peripheral blood (30 cc) was drawn from the subjects' anterocubital vein. Mononuclear cells were isolated from the total blood by using the Ficoll-Hypaque gradient technique. Basal and stimulated intracellular cAMP levels were determined by enzyme immunoassay using a commercially available kit. Aliquots of 5 x 10(6) cells were incubated with or without stimulation of the beta AR-agonist isoproterenol for 5 minutes. Five different concentrations of isoproterenol (10(-3) M to 10(-7) M) were utilized. cAMP levels in both groups were tested statistically by a 2-way repeated-measures ANOVA with 2 predictors, group difference and isoproterenol concentration difference. As with isoproterenol stimulation, the cAMP responses to forskolin, which activates adenylyl cyclase directly and produces cAMP, bypassing the cell surface receptors were also measured. The basal cAMP levels in both groups (myalgia: 0.33 +/- 0.02 pmol/5 x 10(6) cells; control: 0.43 +/- 0.10 pmol/5 x 10(6) cells) were almost identical, and isoproterenol-produced cAMP levels increased dose-dependently in both groups. No significant differences in the mean cAMP levels were observed between the groups (P = .909). Significant increases were observed according to the isoproterenol concentration increase (P < .0001). The cAMP responses to forskolin stimulation also showed no significant group difference (P = .971). These results suggest that beta 2 AR function is not different between localized myalgia subjects and healthy individuals.

Bombesin-dependent pro-MMP-9 activation in prostatic cancer cells requires beta1 integrin engagement.

PubMed

Festuccia, Claudio; Angelucci, Adriano; Gravina, Giovanni; Eleuterio, Enrica; Vicentini, Carlo; Bologna, Mauro

2002-10-15

Bombesin-like peptides, including the mammalian homologue gastrin-releasing peptide, are highly expressed and secreted by neuroendocrine cells in prostate carcinoma tissues and are likely to be related to the progression of this neoplastic disease. Previously, we demonstrated that bombesin increased migration and protease expression in androgen-independent cells. In this work we show that bombesin is able to activate pro-MMP-9 through a mechanism involving the beta1 integrin subunit. In fact, MMP-9 processing was evident only when beta1 integrin was engaged with specific adhesive substrates, such as type I collagen, or when cells were seeded on dishes coated with antibodies against beta1 integrin, resulting in activation of the surface ligand. When exogenous pro-MMP-9 was added to PC3 cells, MMP-9 active forms were produced within 30 min by bombesin-treated cultures while control cultures expressed activated forms only after a longer time and at lower levels. MMP-9 activation required cytoskeleton integrity since this effect was abolished by cytochalasin D. Engagement of beta1 integrin caused an increased membrane-linked uPA activity which was required for MMP-9 activation. The cross talk between bombesin- and beta1-integrin-engaged signals seems to be crucial for the modulation of both membrane-linked uPA activity and MMP-9 activation and triggers complex intracellular signaling pathways requiring activation of tyrosine kinase activity, including that of src and PI3K. The beta1 integrin may be considered an important mechanism by which bombesin induces MMP-9 activation. This finding supports the idea that cellular responses to growth factors may be driven by cell-matrix interactions and stresses the role of neuroendocrine factors in prostate carcinoma progression.

Immunodetection of 11 beta-hydroxysteroid dehydrogenase type 2 in human mineralocorticoid target tissues: evidence for nuclear localization.

PubMed

Shimojo, M; Ricketts, M L; Petrelli, M D; Moradi, P; Johnson, G D; Bradwell, A R; Hewison, M; Howie, A J; Stewart, P M

1997-03-01

11 beta-Hydroxysteroid dehydrogenase (11 beta HSI) is an enzyme complex responsible for the conversion of hormonally active cortisol to inactive cortisone; two isoforms of the enzyme have been cloned and characterized. Clinical observations from patients with the hypertensive syndrome apparent mineralocorticoid excess, recently explained on the basis of mutations in the human 11 beta HSD2 gene, suggest that it is the 11 beta HSD2 isoform that serves a vital role in dictating specificity upon the mineralocorticoid receptor (MR). We have raised a novel antibody in sheep against human 11 beta HSD2 using synthetic multiantigenic peptides and have examined the localization and subcellular distribution of 11 beta HSD2 in mineralocorticoid target tissues. The immunopurified antibody recognized a single band of approximately 44 kDa in placenta, trophoblast, and distal colon. In kidney tissue, two bands of approximately 44 and 48 kDa were consistently observed. No signal was seen in decidua, adrenal, or liver. Immunoperoxidase studies on the mineralocorticoid target tissues, kidney, colon, and parotid gland indicated positive staining in epithelial cells known to express the MR: respectively, renal collecting ducts, surface and crypt colonic epithelial cells, and parotid duct epithelial cells. No staining was seen in these tissues in other sites. The intracellular localization of 11 beta HSD2 in kidney and colon epithelial cells was addressed using confocal laser microscopy. Parallel measurements of 11 beta HSD2 and nuclear propidium iodide fluorescence on sections scanned through an optical section of approximately 0.1 micron indicated significant 11 beta HSD2 immunofluorescence in the nucleus. In human kidney, colon, and salivary gland, 11 beta HSD2 protects the MR from glucocorticoid excess in an autocrine fashion. Furthermore, within these tissues, 11 beta HSD2, which had been considered to be a microsomal enzyme, is also found in the nucleus, suggesting that the interaction between the MR and aldosterone or cortisol is in part a nuclear event.

Alterations induced by E-cadherin and beta-catenin antibodies during the development of Bufo arenarum (Anura-Bufonidae).

PubMed

Izaguirre, M F; Adur, J F; Soler, A P; Casco, V H

2001-10-01

E(epithelial)-cadherin is a member of a calcium-dependent family of cell surface glycoproteins involved in cell-cell adhesion and morphogenesis. Catenins are a large family of proteins that connect the cadherins to the cytoskeleton. They are important for cadherin function and for transducing signals involved in specification of cell fate during embryogenesis. The best characterized catenins include alpha-, beta-, gamma-, and p120-catenin. Using specific antibodies, we studied the expression and distribution of E-cadherin, and alpha- and beta-catenin in developmental stages of Bufo arenarum toad. The three proteins were found co-localized in stages 19 to 41 of development. Surprisingly, E-cadherin was the only of these three proteins found earlier than stage 19. To test whether E-cadherin and beta-catenin have a functional role in Bufo arenarum embryogenesis, stage 17 whole embryos were incubated with anti-E-cadherin and beta-catenin antibodies. Both anti-E-cadherin and anti-beta-catenin antibodies induced severe morphological alterations. However, while alterations produced by the anti-beta-catenin antibody, showed some variability from the most severe (neural tube and notochord duplication) to a simple delay in development, the alterations with anti-E-cadherin were homogeneous. These observations suggest a critical role for E-cadherin and beta-catenin in the early embryonic development of the Bufo arenarum toad. Our results are consistent with the developmental role of these proteins in other species. One of the most surprising findings was the blockage with the anti-beta-catenin antibodies on later embryo stages, and we hypothesize that the partial axes duplication could be mediated by the notochord induction.

Redox-mediated activation of latent transforming growth factor-beta 1

NASA Technical Reports Server (NTRS)

Barcellos-Hoff, M. H.; Dix, T. A.; Chatterjee, A. (Principal Investigator)

1996-01-01

Transforming growth factor beta 1 (TGF beta) is a multifunctional cytokine that orchestrates response to injury via ubiquitous cell surface receptors. The biological activity of TGF beta is restrained by its secretion as a latent complex (LTGF beta) such that activation determines the extent of TGF beta activity during physiological and pathological events. TGF beta action has been implicated in a variety of reactive oxygen-mediated tissue processes, particularly inflammation, and in pathologies such as reperfusion injury, rheumatoid arthritis, and atherosclerosis. It was recently shown to be rapidly activated after in vivo radiation exposure, which also generates reactive oxygen species (ROS). In the present studies, the potential for redox-mediated LTGF beta activation was investigated using a cell-free system in which ROS were generated in solution by ionizing radiation or metal ion-catalyzed ascorbate reaction. Irradiation (100 Gray) of recombinant human LTGF beta in solution induced 26% activation compared with that elicited by standard thermal activation. Metal-catalyzed ascorbate oxidation elicited extremely efficient recombinant LTGF beta activation that matched or exceeded thermal activation. The efficiency of ascorbate activation depended on ascorbate concentrations and the presence of transition metal ions. We postulate that oxidation of specific amino acids in the latency-conferring peptide leads to a conformation change in the latent complex that allows release of TGF beta. Oxidative activation offers a novel route for the involvement of TGF beta in tissue processes in which ROS are implicated and endows LTGF beta with the ability to act as a sensor of oxidative stress and, by releasing TGF beta, to function as a signal for orchestrating the response of multiple cell types. LTGF beta redox sensitivity is presumably directed toward recovery of homeostasis; however, oxidation may also be a mechanism of LTGF beta activation that can be deleterious during disease mechanisms involving chronic ROS production.

Expansion of mesenchymal stem cells from human pancreatic ductal epithelium.

PubMed

Seeberger, Karen L; Dufour, Jannette M; Shapiro, Andrew M James; Lakey, Jonathan R T; Rajotte, Ray V; Korbutt, Gregory S

2006-02-01

Fibroblast-like cells emerging from cultured human pancreatic endocrine and exocrine tissue have been reported. Although a thorough phenotypic characterization of these cells has not yet been carried out, these cells have been hypothesized to be contaminating fibroblasts, mesenchyme and/or possibly beta-cell progenitors. In this study, we expanded fibroblast-like cells from adult human exocrine pancreas following islet isolation and characterized these cells as mesenchymal stem cells (MSCs) based on their cell surface antigen expression and ability to differentiate into mesoderm. Analysis by flow cytometry demonstrated that pancreatic MSCs express cell surface antigens used to define MSCs isolated from bone marrow such as CD13, CD29, CD44, CD49b, CD54, CD90 and CD105. In addition, utilizing protocols used to differentiate MSCs isolated from other somatic tissues, we successfully differentiated pancreatic MSCs into: (1) osteocytes that stained positive for alkaline phosphatase, collagen, mineralization (calcification) and expressed osteocalcin, (2) adipocytes that contained lipid inclusions and expressed fatty acid binding protein 4 and (3) chondrocytes that expressed aggrecan. We also demonstrated that pancreatic MSCs are multipotent and capable of deriving cells of endodermal origin. Pancreatic MSCs were differentiated into hepatocytes that stained positive for human serum albumin and expressed endoderm and liver-specific genes such as GATA 4 and tyrosine aminotransferase. In addition, preliminary protocols used to differentiate these cells into insulin-producing cells resulted in the expression of genes necessary for islet and beta-cell development such as Pax4 and neurogenin 3. Therefore, multipotent MSCs residing within the adult exocrine pancreas could represent a progenitor cell, which when further manipulated could result in the production of functional islet beta-cells.

Functional analysis of alpha5beta1 integrin and lipid rafts in invasion of epithelial cells by Porphyromonas gingivalis using fluorescent beads coated with bacterial membrane vesicles.

PubMed

Tsuda, Kayoko; Furuta, Nobumichi; Inaba, Hiroaki; Kawai, Shinji; Hanada, Kentaro; Yoshimori, Tamotsu; Amano, Atsuo

2008-01-01

Porphyromonas gingivalis, a periodontal pathogen, was previously suggested to exploit alpha5beta1 integrin and lipid rafts to invade host cells. However, it is unknown if the functional roles of these host components are distinct from one another during bacterial invasion. In the present study, we analyzed the mechanisms underlying P. gingivalis invasion, using fluorescent beads coated with bacterial membrane vesicles (MV beads). Cholesterol depletion reagents including methyl-beta-cyclodextrin (MbetaCD) drastically inhibited the entry of MV beads into epithelial cells, while they were less effective on bead adhesion to the cells. Bead entry was also abolished in CHO cells deficient in sphingolipids, components of lipid rafts, whereas adhesion was negligibly influenced. Following MbetaCD treatment, downstream events leading to actin polymerization were abolished; however, alpha5beta1 integrin was recruited to beads attached to the cell surface. Dominant-negative Rho GTPase Rac1 abolished cellular engulfment of the beads, whereas dominant-negative Cdc42 did not. Following cellular interaction with the beads, Rac1 was found to be translocated to the lipid rafts fraction, which was inhibited by MbetaCD. These results suggest that alpha5beta1 integrin, independent of lipid rafts, promotes P. gingivalis adhesion to epithelial cells, while the subsequent uptake process requires lipid raft components for actin organization, with Rho GTPase Rac1.

Human Beta Defensin 2 Selectively Inhibits HIV-1 in Highly Permissive CCR6⁺CD4⁺ T Cells.

PubMed

Lafferty, Mark K; Sun, Lingling; Christensen-Quick, Aaron; Lu, Wuyuan; Garzino-Demo, Alfredo

2017-05-16

Chemokine receptor type 6 (CCR6)⁺CD4⁺ T cells are preferentially infected and depleted during HIV disease progression, but are preserved in non-progressors. CCR6 is expressed on a heterogeneous population of memory CD4⁺ T cells that are critical to mucosal immunity. Preferential infection of these cells is associated, in part, with high surface expression of CCR5, CXCR4, and α4β7. In addition, CCR6⁺CD4⁺ T cells harbor elevated levels of integrated viral DNA and high levels of proliferation markers. We have previously shown that the CCR6 ligands MIP-3α and human beta defensins inhibit HIV replication. The inhibition required CCR6 and the induction of APOBEC3G. Here, we further characterize the induction of apolipoprotein B mRNA editing enzyme (APOBEC3G) by human beta defensin 2. Human beta defensin 2 rapidly induces transcriptional induction of APOBEC3G that involves extracellular signal-regulated kinases 1/2 (ERK1/2) activation and the transcription factors NFATc2, NFATc1, and IRF4. We demonstrate that human beta defensin 2 selectively protects primary CCR6⁺CD4⁺ T cells infected with HIV-1. The selective protection of CCR6⁺CD4⁺ T cell subsets may be critical in maintaining mucosal immune function and preventing disease progression.

An endogenous inhibitor of angiogenesis derived from a transitional cell carcinoma: clipped beta2-glycoprotein-I.

PubMed

Beecken, Wolf-Dietrich C; Engl, Tobias; Ringel, Eva M; Camphausen, Kevin; Michaelis, Martin; Jonas, Dietger; Folkman, Judah; Shing, Yuen; Blaheta, Roman A

2006-09-01

Invasive cell carcinoma of the bladder often develops after complete transurethral excision of superficial transitional cell carcinoma. It has been postulated that primary tumors release angiogenesis-blocking proteins which suppress distant metastases. We have identified an endogenous protein which might be responsible for tumor dormancy. A transitional cell carcinoma cell line was developed (UMUC-3i) which inhibits the growth of a tumor implant at a distant site in SCID mice. Conditioned media of UMUC-3i cultured cells was first pooled and then fractioned, and the capacity of individual components to block endothelial cell growth was tested. The protein fraction responsible for blocking endothelial cell growth was identified by N-terminal amino acid sequencing as well as by mass-spectrometry. The effects of the purified protein in preventing endothelial cell proliferation and tube formation in an in vitro angiogenesis assay was investigated. The plasma protein beta(2)-glycoprotein-I (beta(2)gpI) was isolated and identified from conditioned medium of UMUC-3i cultured cells. Based on the in vitro angiogenesis assay, beta(2)gpI strongly inhibited endothelial cell growth and tube formation, whereby the inhibitory activity corresponded to the clipped version of beta(2)gpI (cbeta(2)gpI). Clipping was induced by adding plasmin at a molar ratio 1:15 (plasmin:substrate). Further analysis indicated that cbeta(2)gpI effects were mediated by annexin II surface receptors expressed on endothelial cells. cbeta2gpI may be involved in blocking angiogenic processes and bladder cancer progression. In this case, cbeta2gpI may be a promising tool in bladder cancer therapy.

Loss of c-myc repression coincides with ovarian cancer resistance to transforming growth factor beta growth arrest independent of transforming growth factor beta/Smad signaling.

PubMed

Baldwin, Rae Lynn; Tran, Hang; Karlan, Beth Y

2003-03-15

Many epithelial carcinomas, including ovarian, are refractory to the antiproliferative effects of transforming growth factor (TGF) beta. In some cancers, TGF-beta resistance has been linked to TGF-beta receptor II (TbetaR-II) and Smad4 mutations; however, in ovarian cancer, the mechanism of resistance remains unclear. Primary ovarian epithelial cell cultures were used as a model system to determine the mechanisms of TGF-beta resistance. To simulate in vivo responses to TGF-beta, primary cultures derived from normal human ovarian surface epithelium (HOSE) and from ovarian carcinomas (CSOC) were grown on collagen I gel, the predominant matrix molecule in the ovarian tumor milieu. When treated with 5 ng/ml TGF-beta for 72 h, HOSE (n = 11) proliferation was inhibited by 20 +/- 21% on average. In contrast, CSOC (n = 10) proliferation was stimulated 5 +/- 10% in response to TGF-beta (a statistically significant difference in response when compared with HOSE; P = 0.001). To dissect the TGF-beta/Smad signaling pathway we used a quantitative RNase protection assay (RPA) for measuring mRNA levels of TGF-beta pathway components in 20 HOSE and 20 CSOC cultures. Basal mRNA levels of TGF-beta receptors I and II, downstream signaling components Smad2, 3, 4, 6, 7, and the transcriptional corepressors Ski and SnoN did not show a statistically significant difference between HOSE and CSOC, and cannot explain their differential susceptibility to TGF-beta-induced cell cycle arrest. To assess functional differences of the TGF-beta pathway in TGF-beta-sensitive HOSE and TGF-beta-resistant CSOC, we measured Smad2/4 and 3/4 complex induction after TGF-beta treatment. HOSE and CSOC showed equivalent Smad2/4 and 3/4 complex induction after TGF-beta exposure for 0, 0.5, 2, and 4 h. It has been proposed that SnoN and Ski are corepressors of the TGF-beta/Smad pathway and undergo TGF-beta-induced degradation followed by reinduction of SnoN mRNA. However, our data show equivalent SnoN degradation in HOSE and CSOC, and equivalent SnoN mRNA induction after TGF-beta treatment. Surprising, TGF-beta-induced Ski degradation was not observed in HOSE or CSOC, suggesting that Ski may not function as a TGF-beta/Smad corepressor in ovarian epithelial cells. These data implied that the TGF-beta/Smad pathway remains functional in CSOC, although CSOC cells are resistant to antimitogenic TGF-beta effects. CSOC resistance to TGF-beta coincided with the loss of c-myc down-regulation. These data suggest that TGF-beta/Smad signaling is blocked downstream of Smad complex formation or that an alternate signaling pathway other than TGF-beta/Smad may transmit TGF-beta-induced cell cycle arrest in the ovarian epithelium.

Effect of beta2-adrenoceptor agonists and other cAMP-elevating agents on inflammatory gene expression in human ASM cells: a role for protein kinase A.

PubMed

Kaur, Manminder; Holden, Neil S; Wilson, Sylvia M; Sukkar, Maria B; Chung, Kian Fan; Barnes, Peter J; Newton, Robert; Giembycz, Mark A

2008-09-01

In diseases such as asthma, airway smooth muscle (ASM) cells play a synthetic role by secreting inflammatory mediators such as granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-6, or IL-8 and by expressing surface adhesion molecules, including ICAM-1. In the present study, PGE(2), forskolin, and short-acting (salbutamol) and long-acting (salmeterol and formoterol) beta(2)-adrenoceptor agonists reduced the expression of ICAM-1 and the release of GM-CSF evoked by IL-1beta in ASM cells. IL-1beta-induced IL-8 release was also repressed by PGE(2) and forskolin, whereas the beta(2)-adrenoceptor agonists were ineffective. In each case, repression of these inflammatory indexes was prevented by adenoviral overexpression of PKIalpha, a highly selective PKA inhibitor. These data indicate a PKA-dependent mechanism of repression and suggest that agents that elevate intracellular cAMP, and thereby activate PKA, may have a widespread anti-inflammatory effect in ASM cells. Since ICAM-1 and GM-CSF are highly NF-kappaB-dependent genes, we used an adenoviral-delivered NF-kappaB-dependent luciferase reporter to examine the effects of forskolin and the beta(2)-adrenoceptor agonists on NF-kappaB activation. There was no effect on luciferase activity measured in the presence of forskolin or beta(2)-adrenoceptor agonists. This finding is consistent with the observation that IL-1beta-induced expression of IL-6, a known NF-kappaB-dependent gene in ASM, was also unaffected by beta(2)-adrenoceptor agonists, forskolin, PGE(2), 8-bromo-cAMP, or rolipram. Collectively, these results indicate that repression of IL-1beta-induced ICAM-1 expression and GM-CSF release by cAMP-elevating agents, including beta(2)-adrenoceptor agonists, may not occur through a generic effect on NF-kappaB.

Specific knockdown of Oct4 and beta2-microglobulin expression by RNA interference in human embryonic stem cells and embryonic carcinoma cells.

PubMed

Matin, Maryam M; Walsh, James R; Gokhale, Paul J; Draper, Jonathan S; Bahrami, Ahmad R; Morton, Ian; Moore, Harry D; Andrews, Peter W

2004-01-01

We have used RNA interference (RNAi) to downregulate beta2-microglobulin and Oct4 in human embryonal carcinoma (hEC) cells and embryonic stem (hES) cells, demonstrating that RNAi is an effective tool for regulating specific gene activity in these human stem cells. The knockdown of Oct4 but not beta2-microglobulin expression in both EC and ES cells resulted in their differentiation, as indicated by a marked change in morphology, growth rate, and surface antigen phenotype, with respect to SSEA1, SSEA3, and TRA-1-60 expression. Expression of hCG and Gcm1 was also induced following knockdown of Oct4 expression, in both 2102Ep hEC cells and in H7 and H14 hES cells, consistent with the conclusion that, as in the mouse, Oct4 is required to maintain the undifferentiated stem cell state, and that differentiation to trophectoderm occurs in its absence. NTERA2 hEC cells also differentiated, but not to trophectoderm, suggesting their equivalence to a later stage of embryogenesis than other hEC and hES cells.

Rotavirus RRV associates with lipid membrane microdomains during cell entry.

PubMed

Isa, Pavel; Realpe, Mauricio; Romero, Pedro; López, Susana; Arias, Carlos F

2004-05-01

Rotavirus cell entry is a multistep process, not completely understood, which requires at least four interactions between the virus and cell surface molecules. In this work, we investigated the role of the sphingolipid- and cholesterol-enriched lipid microdomains (rafts) in the entry of rotavirus strain RRV to MA104 cells. We found that ganglioside GM1, integrin subunits alpha2 and beta3, and the heat shock cognate protein 70 (hsc70), all of which have been implicated as rotavirus receptors, are associated with TX-100 and Lubrol WX detergent-resistant membranes (DRMs). Integrin subunits alpha2 and beta3 were found to be particularly enriched in DRMs resistant to lysis by Lubrol WX. When purified RRV particles were incubated with cells at 4 degrees C, about 10% of the total infectious virus was found associated with DRMs, and the DRM-associated virus increased to 37% in Lubrol-resistant membrane domains after 60-min incubation at 37 degrees C. The virus was excluded from DRMs if the cells were treated with methyl-beta-cyclodextrin (MbetaCD). Immunoblot analysis of the viral proteins showed that the virus surface proteins became enriched in DRMs upon incubation at 37 degrees C, being almost exclusively localized in Lubrol-resistant DRMs after 60 min. These data suggest that detergent-resistant membrane domains play an important role in the cell entry of rotaviruses, which could provide a platform to facilitate the efficient interaction of the rotavirus receptors with the virus particle.

Dynamics of beta-cell turnover: evidence for beta-cell turnover and regeneration from sources of beta-cells other than beta-cell replication in the HIP rat.

PubMed

Manesso, Erica; Toffolo, Gianna M; Saisho, Yoshifumi; Butler, Alexandra E; Matveyenko, Aleksey V; Cobelli, Claudio; Butler, Peter C

2009-08-01

Type 2 diabetes is characterized by hyperglycemia, a deficit in beta-cells, increased beta-cell apoptosis, and islet amyloid derived from islet amyloid polypeptide (IAPP). These characteristics are recapitulated in the human IAPP transgenic (HIP) rat. We developed a mathematical model to quantify beta-cell turnover and applied it to nondiabetic wild type (WT) vs. HIP rats from age 2 days to 10 mo to establish 1) whether beta-cell formation is derived exclusively from beta-cell replication, or whether other sources of beta-cells (OSB) are present, and 2) to what extent, if any, there is attempted beta-cell regeneration in the HIP rat and if this is through beta-cell replication or OSB. We conclude that formation and maintenance of adult beta-cells depends largely ( approximately 80%) on formation of beta-cells independent from beta-cell duplication. Moreover, this source adaptively increases in the HIP rat, implying attempted beta-cell regeneration that substantially slows loss of beta-cell mass.

Studies of hemidesmosomes in human amnion: the use of a detergent extraction protocol for compositional and ultrastructural analysis and preparation of a hemidesmosome-enriched fraction from tissue.

PubMed

Behzad, F; Jones, C J; Ball, S; Alvares, T; Aplin, J D

1995-01-01

A method is described for the sequential detergent and high ionic strength extraction of human amnion with the progressive enrichment of the intermediate filament (IF) cytoskeleton and its associated structures including hemidesmosomes (HD). TEM of the extracted epithelium in situ reveals IF bundles beneath the apical cell surface, around the nucleus and at the lateral edges of the cells where association with desmosomes occurs. IF bundles are also very prominent within basal cell processes where they loop through the cytoplasm adjacent to the HDs. A novel connecting filament network is observed running between the IFs and the hemidesmosomal dense plaque. The adjacent IF network contains both cytokeratin and vimentin, the latter revealed much more fully as a result of the extraction protocol. The hemidesmosomal plasma membrane contains integrin subunits alpha 6 and beta 4 and these are quantitatively retained as the basal cell surface during extraction, while nonjunctional plasma membrane is solubilised. Integrin beta 1 is found at the basolateral cell surface but, like actin, is extracted quantitatively and is not present in HDs. The extracted epithelial cells may be recovered by scraping and the IF network depolymerised to produce a particulate fraction containing short residual IFs, associated thin filaments and plaque material. This fraction contains immunoreactive cytokeratin and vimentin. Integrin alpha 6 beta 4 has been used as a biochemical criterion of the presence of HD material in the fraction. Both subunits are highly enriched. The fraction also contains the hemidesmosomal components HD1, BP230 and BP180. This method is likely to be useful in further characterisation of the HD.

The effects of interferon-alpha/beta in a model of rat heart transplantation

NASA Technical Reports Server (NTRS)

Slater, A. D.; Klein, J. B.; Sonnenfeld, G.; Ogden, L. L. 2nd; Gray, L. A. Jr

1992-01-01

Interferons have multiple immunologic effects. One such effect is the activation of expression of cell surface antigens. Interferon alpha/beta enhance expression of class I but not class II histocompatibility antigens. Contradictory information has been published regarding the effect of interferon-alpha/beta administration in patients with kidney transplantation. In a model of rat heart transplantation we demonstrated that administration of interferon-alpha/beta accelerated rejection in a dose-dependent fashion in the absence of maintenance cyclosporine. Animals treated with maintenance cyclosporine had evidence of increased rejection at 20 days that was resolved completely at 45 days with cyclosporine alone.

Granulocyte-macrophage and macrophage colony-stimulating factors differentially regulate alpha v integrin expression on cultured human macrophages.

PubMed

De Nichilo, M O; Burns, G F

1993-03-15

The colony-stimulating factors (CSFs) greatly influence mature macrophage function in vitro: macrophage (M)-CSF induces maturation of monocytes and enhances differentiated cell function; granulocyte-macrophage (GM)-CSF stimulates a variety of antimicrobial functions. In vivo M-CSF is thought to promote differentiation, and GM-CSF is thought to potentiate the inflammatory response. One mechanism by which these differential effects may be achieved is through the receptor-mediated interaction of macrophages with their extracellular matrix. Here we show that M-CSF induces specifically the expression of the alpha v beta 5 integrin receptor, whereas GM-CSF rapidly induces mRNA and surface expression of the alpha v beta 3 integrin. The M-CSF-treated cells acquire a flattened epitheloid phenotype, and on vitronectin the alpha v beta 5 is located in adhesion plaques. These cells do not bind collagen or laminin. In contrast, cells treated with GM-CSF adopt an elongated phenotype on a number of substrates, including collagen and laminin, and express alpha v beta 3 at the leading edge of cells on vitronectin. These results suggest that a primary means by which the CSFs exert their individual effects on mature cells may be through regulating integrin expression.

Effect of mitomycin C on IL-1R expression, IL-1-related hepatocyte growth factor secretion and corneal epithelial cell migration.

PubMed

Chen, Tsan-Chi; Chang, Shu-Wen

2010-03-01

To investigate how mitomycin C (MMC) modulates hepatocyte growth factor (HGF) and keratinocyte growth factor (KGF) secretions in human corneal fibroblasts and regulates human corneal epithelial (HCE) cell migration. Primary human corneal fibroblasts were treated with MMC (0.05, 0.1, or 0.2 mg/mL for 5 minutes) and were cultivated with or without interleukin (IL)-1beta. Transcript and secretion of HGF and KGF were determined by quantitative real-time RT-PCR and Western blot analysis, respectively. The effect of MMC-treated fibroblasts on HCE cell migration was evaluated using a transwell migration assay. The influence of MMC on HGF expression/secretion and HCE cell migration was further confirmed by RNA interference. The number of IL-1 receptors (IL-1R) on the fibroblast surface was analyzed by flow cytometry. MMC alone did not affect endogenous HGF expression, whereas IL-1beta alone significantly upregulated HGF transcripts and secretion. By modifying IL-1R numbers, MMC further upregulated IL-1beta-related HGF expression at a concentration of 0.05 mg/mL but to a lesser extent at 0.1 and 0.2 mg/mL. KGF transcripts and intracellular expression were suppressed by MMC dose dependently in the presence or absence of IL-1beta, whereas KGF secretion was not affected. Conditioned medium from MMC-treated fibroblasts exerted a similar concentration-dependent effect on HCE cell migration, enhancing migration most significantly at 0.05 mg/mL MMC in the presence of IL-1beta. The MMC dose-dependent modulation of HCE cell migration was abolished in HGF-silenced fibroblasts. MMC differentially modulated IL-1R expression at various concentrations and regulated HGF and KGF differently. MMC alone did not alter HGF expression. In the presence of IL-1beta, MMC-treated corneal fibroblasts modified HCE cell migration through IL-1beta-induced HGF secretion.

Beta 1D integrin displaces the beta 1A isoform in striated muscles: localization at junctional structures and signaling potential in nonmuscle cells.

PubMed

Belkin, A M; Zhidkova, N I; Balzac, F; Altruda, F; Tomatis, D; Maier, A; Tarone, G; Koteliansky, V E; Burridge, K

1996-01-01

The cytoplasmic domains of integrins provide attachment of these extracellular matrix receptors to the cytoskeleton and play a critical role in integrin-mediated signal transduction. In this report we describe the identification, expression, localization, and initial functional characterization of a novel form of beta 1 integrin, termed beta 1D. This isoform contains a unique alternatively spliced cytoplasmic domain of 50 amino acids, with the last 24 amino acids encoded by an additional exon. Of these 24 amino acids, 11 are conserved when compared to the beta 1A isoform, but 13 are unique (Zhidkova, N. I., A. M. Belkin, and R. Mayne. 1995. Biochem. Biophys. Res. Commun. 214:279-285; van der Flier, A., I. Kuikman, C. Baudoin, R, van der Neuf, and A. Sonnenberg. 1995. FEBS Lett. 369:340-344). Using an anti-peptide antibody against the beta 1D integrin subunit, we demonstrated that the beta 1D isoform is synthesized only in skeletal and cardiac muscles, while very low amounts of beta 1A were detected by immunoblot in striated muscles. Whereas beta 1A could not be detected in adult skeletal muscle fibers and cardiomyocytes by immunofluorescence, beta 1D was localized to the sarcolemma of both cell types. In skeletal muscle, beta 1D was concentrated in costameres, myotendinous, and neuromuscular junctions. In cardiac muscle this beta 1 isoform was found in costamers and intercalated discs. beta 1D was associated with alpha 7A and alpha 7B in adult skeletal muscle. In cardiomyocytes of adult heart, alpha 7B was the major partner for the beta 1D isoform. beta 1D could not be detected in proliferating C2C12 myoblasts, but it appeared immediately after myoblast fusion and its amount continued to rise during myotube growth and maturation. In contrast, expression of the beta 1A isoform was downregulated during myodifferentiation in culture and it was completely displaced by beta 1D in mature differentiated myotubes. We also analyzed some functional properties of the beta 1D integrin subunit. Expression of human beta 1D in CHO cells led to its localization at focal adhesions. Clustering of this integrin isoform on the cell surface stimulated tyrosine phosphorylation of pp125FAK (focal adhesion kinase) and caused transient activation of mitogen-activated protein (MAP) kinases. These data indicate that beta 1D and beta 1A integrin isoforms are functionally similar with regard to integrin-mediated signaling.

MUC1 and colorectal cancer pathophysiology considerations.

PubMed

Niv, Yaron

2008-04-14

Several lines of evidence point towards a biological role of mucin and particularly MUC1 in colorectal cancer. A positive correlation was described between mucin secretion, proliferation, invasiveness, metastasis and bad prognosis. But, the role of MUC1 in cancer progression is still controversial and somewhat confusing. While Mukherjee and colleagues developed MUC1-specific immune therapy in a CRC model, Lillehoj and co-investigators showed recently that MUC1 inhibits cell proliferation by a beta-catenin-dependent mechanism. In carcinoma cells the polarization of MUC1 is lost and the protein is over expressed at high levels over the entire cell surface. A competitive interaction between MUC1 and E-cadherin, through beta-catenin binding, disrupts E-cadherin-mediated cell-cell interactions at sites of MUC1 expression. In addition, the complex of MUC1-beta-catenin enters the nucleus and activates T-cell factor/leukocyte enhancing factor 1 transcription factors and activates gene expression. This mechanism may be similar to that just described for DCC and UNC5H, which induced apoptosis when not engaged with their ligand netrin, but mediate signals for proliferation, differentiation or migration when ligand bound.

Decursin and PDBu: two PKC activators distinctively acting in the megakaryocytic differentiation of K562 human erythroleukemia cells.

PubMed

Kim, Hyeon Ho; Ahn, Kyung Seop; Han, Hogyu; Choung, Se Young; Choi, Sang-Yun; Kim, Ik-Hwan

2005-12-01

Protein kinase C (PKC) plays an important role in the proliferation and differentiation of various cell types including normal and leukemic hematopoietic cells. Phorbol 12,13-dibutyrate (PDBu) induces the megakaryocytic differentiation of K562 human erythroleukemia cells through PKC activation. Decursin, a pyranocoumarin from Angelica gigas, exhibits the cytotoxic effects on various human cancer cell lines and in vitro PKC activation. We report here the differences between two PKC activators, tumor-suppressing decursin and tumor-promoting PDBu, in their actions on the megakaryocytic differentiation of K562 cells. First of all, decursin inhibited PDBu-induced bleb formation in K562 cells. Decursin also inhibited the PDBu-induced megakaryocytic differentiation of K562 cells that is characterized by an increase in substrate adhesion, the secretion of granulocyte/macrophage colony stimulating factor (GM-CSF) and interleukin-6 (IL-6), and the surface expression of integrin beta3. The binding of PDBu to PKC was competitively inhibited by decursin. Decursin induced the more rapid down-regulation of PKC alpha and betaII isozymes than that induced by PDBu in K562 cells. Unlike PDBu, decursin promoted the translocation of PKC alpha and betaII to the nuclear membrane. Decursin-induced faster down-regulation and nuclear translocation of PKC alpha and betaII were not affected by the presence of PDBu. All these results indicate that decursin and phorbol ester are PKC activators distinctively acting in megakaryocytic differentiation and PKC modulation in K562 leukemia cells.

Peptide ligands targeting integrin alpha3beta1 in non-small cell lung cancer.

PubMed

Lau, Derick; Guo, Linlang; Liu, Ruiwu; Marik, Jan; Lam, Kit

2006-06-01

Lung cancer is one of the most common cancers and is the leading cause of cancer death. We wish to identify peptide ligands for unique cell surface receptors of non-small lung cancer with the hope of developing these ligands as diagnostic and therapeutic agents. Using the method of 'one-bead one-peptide' combinatorial chemistry, a library of random cyclic octapeptides was synthesized on polystyrene beads. This library was used to screen for peptides that promoted attachment of lung adenocarcinoma cells employing a 'cell-growth-on-bead' assay. Consensus peptide sequences of cNGXGXXc were identified. These peptides promoted cell adhesion by targeting integrin alpha3beta1 over-expressed in non-small lung cancer cells. These peptide beads can be applied to capture cancer cells in malignant pleural fluid for purpose of diagnosis of lung cancer.

Role of {alpha}{sub v}{beta}{sub 5} integrin receptor in endocytosis of crocidolite and its effect on intracellular glutathione levels in human lung epithelial (A549) cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pande, Priyadarshini; Mosleh, Tariq A.; Aust, Ann E.

Crocidolite, containing 27% iron by weight, is the most carcinogenic form of asbestos. Crocidolite fibers are endocytized by {alpha}{sub v}{beta}{sub 5} integrin receptors in rabbit pleural mesothelial cells. We show here that crocidolite fibers are endocytized in human lung epithelial (A549) cells and in primary small airway epithelial (SAEC) cells. Presence of the integrin {alpha}{sub v}{beta}{sub 5} blocking antibody, P1F6, significantly reduced the uptake of crocidolite fibers in A549 cells. Thus, the integrin {alpha}{sub v}{beta}{sub 5} receptor is involved in endocytosis of crocidolite fibers in A549 cells as well. Previously, it has been observed that asbestos fibers lead to changesmore » in the intracellular redox environment, i.e. a marked decrease in intracellular glutathione concentrations and an increase in the extracellular glutathione in A549 cells. In addition, the decrease in intracellular glutathione was found to be largely independent of iron present on the surface of the fiber. A549 cells were treated with crocidolite in the presence of endocytosis inhibitor cytochalasin D. Our data indicate that, upon preventing endocytosis, we were able to reverse the decrease in total intracellular glutathione. The decrease in total intracellular glutathione could also be prevented in the presence of the monoclonal antibody P1F6. Thus, we observed that endocytosis of crocidolite fibers via integrin {alpha}{sub v}{beta}{sub 5} receptor is linked to the marked decrease in total intracellular glutathione in A549 cells.« less

In vitro biocorrosion of Co-Cr-Mo implant alloy by macrophage cells.

PubMed

Lin, Hsin-Yi; Bumgardner, Joel D

2004-11-01

We hypothesized that macrophage cells and their released reactive chemical species (RCS) affect Co-Cr-Mo alloy's corrosion properties and that alloy corrosion products change macrophage cell behavior. A custom cell culture corrosion cell was used to evaluate how culture medium, cells, and RCS altered alloy corrosion in 3-day tests. Corrosion was evaluated by measuring total charge transfer at a constant potential using a potentiostat and metal ion release by atomic emission spectroscopy. Viability, proliferation, and NO (nitric oxide) and IL-1beta (interlukin-1beta) release were used to assess cellular response to alloy corrosion products. In the presence of activated cells, total charge transfers and Co ion release were the lowest (p < 0.05). This was attributed to an enhancement of the surface oxide by RCS. Cr and Mo release were not different between cells and activated cells. Low levels of metal ions did not affect cell viability, proliferation, or NO release, though IL-1beta released from the activated cells was higher on the alloy compared to the controls. These data support the hypothesis that macrophage cells and their RCS affect alloy corrosion. Changes in alloy corrosion by cells may be important to the development of host responses to the alloy and its corrosion products.

Signalling through NK1.1 triggers NK cells to die but induces NK T cells to produce interleukin-4.

PubMed

Asea, A; Stein-Streilein, J

1998-02-01

In vivo inoculation of specific antibody is an accepted protocol for elimination of specific cell populations. Except for anti-CD3 and anti-CD4, it is not known if the depleted cells are eliminated by signalling through the target molecule or through a more non-specific mechanism. C57BL/6 mice were inoculated with anti-natural killer (NK1.1) monoclonal antibody (mAb). Thereafter spleen cells were harvested, stained for both surface and intracellular markers, and analysed by flow cytometry. As early as 2 hr post inoculation, NK cells were signalled to become apoptotic while signalling through the NK1.1 molecule activated NK1.1+ T-cell receptor (TCR)+ (NK T) cells to increase in number, and produce interleukin-4 (IL-4). Anti NK1.1 mAb was less efficient at signalling apoptosis in NK cells when NK T-cell deficient [beta 2-microglobulin beta 2m-deficient] mice were used compared with wild type mice. Efficient apoptotic signalling was restored when beta 2m-deficient mice were reconstituted with NK T cells. NK-specific antibody best signals the apoptotic process in susceptible NK cells when resistant NK T cells are present, activated, and secrete IL-4.

Alzheimer Abeta(1-42) monomer adsorbed on the self-assembled monolayers.

PubMed

Wang, Qiuming; Zhao, Jun; Yu, Xiang; Zhao, Chao; Li, Lingyan; Zheng, Jie

2010-08-03

Amyloid-beta (Abeta) peptide aggregation on the cell membranes is a key pathological event responsible for neuron cell death in Alzheimer's disease (AD). We present a collection of molecular docking and molecular dynamics simulations to study the conformational dynamics and adsorption behavior of Abeta monomer on the self-assembled monolayer (SAM), in comparison to Abeta structure in bulk solution. Two distinct Abeta conformations (i.e., alpha-helix and beta-hairpin) are selected as initial structures to mimic different adsorption states, whereas four SAM surfaces with different end groups in hydrophobicity and charge distribution are used to examine the effect of surface chemistry on Abeta structure and adsorption. Simulation results show that alpha-helical monomer displays higher structural stability than beta-hairpin monomer on all SAMs, suggesting that the preferential conformation of Abeta monomer could be alpha-helical or random structure when bound to surfaces. Structural stability and adsorption behavior of Abeta monomer on the SAMs originates from competitive interactions between Abeta and SAM and between SAM and interfacial water, which involve the conformation of Abeta, the surface chemistry of SAM, and the structure and dynamics of interfacial waters. The relative net binding affinity of Abeta with the SAMs is in the favorable order of COOH-SAM > NH(2)-SAM > CH(3)-SAM > OH-SAM, highlighting the importance of electrostatic and hydrophobic interactions for driving Abeta adsorption at the SAMs, but both interactions contribute differently to each Abeta-SAM complex. This work provides parallel insights into the understanding of Abeta structure and aggregation on cell membrane.

Integrin alpha 3 beta 1 participates in the phagocytosis of extracellular matrix molecules by human breast cancer cells.

PubMed

Coopman, P J; Thomas, D M; Gehlsen, K R; Mueller, S C

1996-11-01

The mechanisms and receptors involved in phagocytosis by nonhematopoietic cells are not well understood. The involvement of the alpha 3 beta 1 integrin in phagocytosis of the extracellular matrix by human breast cancer cells was studied. The possible role of this integrin was suggested since alpha 3 and beta 1 but not alpha 2 subunits are concentrated at membrane sites where local degradation of fluorescently labeled gelatin occurs. Strikingly, anti-alpha 3 integrin monoclonal antibodies (mAbs) stimulate the phagocytosis of fluorescently labeled gelatin films, gelatin beads, and Matrigel films in a quantitative phagocytosis assay. Stimulation of the gelatin uptake by the anti-alpha 3 mAb is dose responsive, saturable, and time dependent. Antibodies against other integrin subunits have a lower stimulatory effect (anti-beta 1) or no significant effect (anti-alpha 2, -alpha 5, -alpha 6, and -alpha v) on gelatin phagocytosis. The synthetic HGD-6 human laminin peptide that binds specifically the alpha 3 beta 1 integrin, but not the scrambled HSGD-6 control peptide, also markedly stimulates gelatin uptake in a dose-responsive way. Furthermore, the stimulatory effects of the HGD-6 peptide and the anti-alpha 3 mAb are additive, suggesting that they might promote phagocytosis in different ways. Other laminin (YIGSR, IKVAV) and fibronectin (GRGDS) peptides have no effect on gelatin phagocytosis. Immunofluorescence shows that the alpha 3 and the beta 1, but not the alpha 2 integrin subunit, concentrate into patches on the cell surface after treatment with their respective mAbs. And, both gelatin and the alpha 3 beta 1 but not the alpha 2 beta 1 integrin are cointernalized and routed to acidic vesicles such as lysosomes. In conclusion, we demonstrate that human breast cancer cells locally degrade and phagocytose the extracellular matrix and show for the first time that the alpha 3 beta 1 integrin participates in this phagocytosis. We hypothesize that the anti-alpha 3 antibodies and the laminin peptide HGD-6 activate the alpha 3 beta 1 integrin, which results in a downstream signaling cascade stimulating phagocytosis.

Murine Ia-associated invariant chain's processing to complex oligosaccharide forms and its dissociation from the I-Ak complex.

PubMed

Holt, G D; Swiedler, S J; Freed, J H; Hart, G W

1985-07-01

The processing of murine invariant chain (Ii) to a cell surface form bearing complex N-linked oligosaccharides has been demonstrated in the B cell lymphoma, AKTB-1b. In addition, the rate of processing of pulse-labeled Ii has been determined relative to its rate of dissociation from the alpha/beta complex of I-Ak. Ii, alpha-, and beta-chains were immunoprecipitated with anti-I-Ak or anti-Ii monoclonal antibodies. The heretofore uncharacterized complex oligosaccharide form of Ii (Ii-c) was identified in gel-purified immunoprecipitates by peptide mapping with reverse-phase HPLC. Ii-c is resistant to deglycosylation by Endo H, which is specific for high-mannose N-linkages, but can be digested with Endo F, a glycosidase capable of cleaving both complex and high-mannose N-linked oligosaccharides. Immunoprecipitation of surface iodinated cells indicates that Ii-c is expressed on the plasma membrane. Pulse-chase metabolic labeling data show that the processing of Ii to Ii-c occurs with a t1/2 of about 120 min. In contrast, the processing of both alpha- and beta-chains of I-Ak to complex forms occurs with a t1/2 of 15 to 20 min. Our data show that Ii-hm begins to dissociate rapidly from the I-Ak complex after 100 to 120 min of chase. Only a small amount (less than 5% on a per mole basis) of Ii-c was found associated with the I-Ak complexes after 300 min of continuous metabolic labeling. These results are consistent with Ii serving as a carrier for Ia antigens as they are transported to the cell surface. In addition, they suggest that the processing of Ii to Ii-c, or a late processing event of the alpha- and beta-chains, such as their sialylation, may be a possible mechanism for inducing the dissociation of Ii from the I-Ak complex.

Desialylation of glycoconjugates on the surface of monocytes activates the extracellular signal-related kinases ERK 1/2 and results in enhanced production of specific cytokines.

PubMed

Stamatos, Nicholas M; Curreli, Sabrina; Zella, Davide; Cross, Alan S

2004-02-01

Modulation of the sialic acid content of cell-surface glycoproteins and glycolipids influences the functional capacity of cells of the immune system. The role of sialidase(s) and the consequent desialylation of cell surface glycoconjugates in the activation of monocytes have not been established. In this study, we show that desialylation of glycoconjugates on the surface of purified monocytes using exogenous neuraminidase (NANase) activated extracellular signal-regulated kinase 1/2 (ERK 1/2), an intermediate in intracellular signaling pathways. Elevated levels of phosphorylated ERK 1/2 were detected in desialylated monocytes after 2 h of NANase treatment, and increased amounts persisted for at least 2 additional hours. Desialylation of cell surface glycoconjugates also led to increased production of interleukin (IL)-6, macrophage inflammatory protein (MIP)-1alpha, and MIP-1beta by NANase-treated monocytes that were maintained in culture. Neither increased levels of phosphorylated ERK 1/2 nor enhanced production of cytokines were detected when NANase was heat-inactivated before use, demonstrating the specificity of NANase action. Treatment of monocytes with gram-negative bacterial lipopolysaccharide (LPS) also led to enhanced production of IL-6, MIP-1alpha, and MIP-1beta. The amount of each of these cytokines that was produced was markedly increased when monocytes were desialylated with NANase before exposure to LPS. These results suggest that changes in the sialic acid content of surface glycoconjugates influence the activation of monocytes.

TGF-{beta} receptors, in a Smad-independent manner, are required for terminal skeletal muscle differentiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Droguett, Rebeca; Cabello-Verrugio, Claudio; Santander, Cristian

2010-09-10

Skeletal muscle differentiation is strongly inhibited by transforming growth factor type {beta} (TGF-{beta}), although muscle formation as well as regeneration normally occurs in an environment rich in this growth factor. In this study, we evaluated the role of intracellular regulatory Smads proteins as well as TGF-{beta}-receptors (TGF-{beta}-Rs) during skeletal muscle differentiation. We found a decrease of TGF-{beta} signaling during differentiation. This phenomenon is explained by a decline in the levels of the regulatory proteins Smad-2, -3, and -4, a decrease in the phosphorylation of Smad-2 and lost of nuclear translocation of Smad-3 and -4 in response to TGF-{beta}. No changemore » in the levels and inhibitory function of Smad-7 was observed. In contrast, we found that TGF-{beta}-R type I (TGF-{beta}-RI) and type II (TGF-{beta}-RII) increased on the cell surface during skeletal muscle differentiation. To analyze the direct role of the serine/threonine kinase activities of TGF-{beta}-Rs, we used the specific inhibitor SB 431542 and the dominant-negative form of TGF-{beta}-RII lacking the cytoplasmic domain. The TGF-{beta}-Rs were important for successful muscle formation, determined by the induction of myogenin, creatine kinase activity, and myosin. Silencing of Smad-2/3 expression by specific siRNA treatments accelerated myogenin, myosin expression, and myotube formation; although when SB 431542 was present inhibition in myosin induction and myotube formation was observed, suggesting that these last steps of skeletal muscle differentiation require active TGF-{beta}-Rs. These results suggest that both down-regulation of Smad regulatory proteins and cell signaling through the TGF-{beta} receptors independent of Smad proteins are essential for skeletal muscle differentiation.« less

Abrogation of E-cadherin-mediated cell-cell contact in mouse embryonic stem cells results in reversible LIF-independent self-renewal.

PubMed

Soncin, Francesca; Mohamet, Lisa; Eckardt, Dominik; Ritson, Sarah; Eastham, Angela M; Bobola, Nicoletta; Russell, Angela; Davies, Steve; Kemler, Rolf; Merry, Catherine L R; Ward, Christopher M

2009-09-01

We have previously demonstrated that differentiation of embryonic stem (ES) cells is associated with downregulation of cell surface E-cadherin. In this study, we assessed the function of E-cadherin in mouse ES cell pluripotency and differentiation. We show that inhibition of E-cadherin-mediated cell-cell contact in ES cells using gene knockout (Ecad(-/-)), RNA interference (EcadRNAi), or a transhomodimerization-inhibiting peptide (CHAVC) results in cellular proliferation and maintenance of an undifferentiated phenotype in fetal bovine serum-supplemented medium in the absence of leukemia inhibitory factor (LIF). Re-expression of E-cadherin in Ecad(-/-), EcadRNAi, and CHAVC-treated ES cells restores cellular dependence to LIF supplementation. Although reversal of the LIF-independent phenotype in Ecad(-/-) ES cells is dependent on the beta-catenin binding domain of E-cadherin, we show that beta-catenin null (betacat(-/-)) ES cells also remain undifferentiated in the absence of LIF. This suggests that LIF-independent self-renewal of Ecad(-/-) ES cells is unlikely to be via beta-catenin signaling. Exposure of Ecad(-/-), EcadRNAi, and CHAVC-treated ES cells to the activin receptor-like kinase inhibitor SB431542 led to differentiation of the cells, which could be prevented by re-expression of E-cadherin. To confirm the role of transforming growth factor beta family signaling in the self-renewal of Ecad(-/-) ES cells, we show that these cells maintain an undifferentiated phenotype when cultured in serum-free medium supplemented with Activin A and Nodal, with fibroblast growth factor 2 required for cellular proliferation. We conclude that transhomodimerization of E-cadherin protein is required for LIF-dependent ES cell self-renewal and that multiple self-renewal signaling networks subsist in ES cells, with activity dependent upon the cellular context.

Feline Glycoprotein A Repetitions Predominant Anchors Transforming Growth Factor Beta on the Surface of Activated CD4+CD25+ Regulatory T Cells and Mediates AIDS Lentivirus-Induced T Cell Immunodeficiency

PubMed Central

Miller, Michelle M.; Fogle, Jonathan E.; Ross, Peter

2013-01-01

Abstract Using the feline immunodeficiency virus (FIV) model for AIDS-lentivirus infection, our laboratory has previously demonstrated that T regulatory (Treg) cell-mediated immune T and B cell dysfunction contributes to lentivirus persistence and chronic disease through membrane bound transforming growth factor beta (mTGFb). Studying Treg cells in the context of infection has been problematic as no inducible marker for activated Treg cells had been identified. However, recent reports in human Treg studies have described a novel protein, glycoprotein A repetitions predominant (GARP), as a unique marker of activated human Treg cells that anchors mTGFb. Herein we extend these studies to the feline Treg system, identifying feline GARP and demonstrating that human and feline GARP proteins are homologous in structure, expression pattern, and ability to form a complex with TGFb. We further demonstrate that GARP and TGFb form a complex on the surface of activated Treg cells and that these GARP+TGFb+ Treg cells are highly efficient suppressor cells. Analysis of expression of this Treg activation marker in the FIV-AIDS model reveals an up-regulation of GARP expressing Treg cells during chronic FIV infection. We demonstrate that the GARP+ Treg cells from FIV-infected cats suppress T helper cells in vivo and that blocking GARP or TGFb eliminates this suppression. These data suggest that GARP is expressed in complex with TGFb on the surface of activated Treg cells and plays an important role in TGFb+ Treg-mediated T cell immune suppression during lentivirus infection. PMID:23373523

Feline glycoprotein A repetitions predominant anchors transforming growth factor beta on the surface of activated CD4(+)CD25(+) regulatory T cells and mediates AIDS lentivirus-induced T cell immunodeficiency.

PubMed

Miller, Michelle M; Fogle, Jonathan E; Ross, Peter; Tompkins, Mary B

2013-04-01

Using the feline immunodeficiency virus (FIV) model for AIDS-lentivirus infection, our laboratory has previously demonstrated that T regulatory (Treg) cell-mediated immune T and B cell dysfunction contributes to lentivirus persistence and chronic disease through membrane bound transforming growth factor beta (mTGFb). Studying Treg cells in the context of infection has been problematic as no inducible marker for activated Treg cells had been identified. However, recent reports in human Treg studies have described a novel protein, glycoprotein A repetitions predominant (GARP), as a unique marker of activated human Treg cells that anchors mTGFb. Herein we extend these studies to the feline Treg system, identifying feline GARP and demonstrating that human and feline GARP proteins are homologous in structure, expression pattern, and ability to form a complex with TGFb. We further demonstrate that GARP and TGFb form a complex on the surface of activated Treg cells and that these GARP(+)TGFb(+) Treg cells are highly efficient suppressor cells. Analysis of expression of this Treg activation marker in the FIV-AIDS model reveals an up-regulation of GARP expressing Treg cells during chronic FIV infection. We demonstrate that the GARP(+) Treg cells from FIV-infected cats suppress T helper cells in vivo and that blocking GARP or TGFb eliminates this suppression. These data suggest that GARP is expressed in complex with TGFb on the surface of activated Treg cells and plays an important role in TGFb(+) Treg-mediated T cell immune suppression during lentivirus infection.

Novel Confocal Microscopic and Flow Cytometric Based Assays to Visualize and Detect the (Beta)2-Adrenergic Receptor in Human Lymphocyte and Mononuclear Cell Populations

NASA Technical Reports Server (NTRS)

Salicru, A. N.; Crucian, B. E.; Nelman, M. A.; Sams, C. F.; Actor, J. K.; Marshall, G. D.

2006-01-01

The data show that immunophenotyping of leukocyte populations with (beta)2AR is possible with the commercially available Ab, although the FC assay is limited to the IST as a result of the Ab binding site to the intracellular C-terminus of the 2AR. The FC assay has applications for measuring alterations in total (beta)2AR in human leukocyte populations as changes in fluorescence. In addition, CM confirms that both surface and intracellular compartments stain positively for the (beta)2AR and can be used for qualitative assays that screen for changes in receptor compartmentalization and localization.

Amyloid precursor protein and Presenilin 1 interaction studied by FRET in human H4 cells.

PubMed

Nizzari, Mario; Venezia, Valentina; Bianchini, Paolo; Caorsi, Valentina; Diaspro, Alberto; Repetto, Emanuela; Thellung, Stefano; Corsaro, Alessandro; Carlo, Pia; Schettini, Gennaro; Florio, Tullio; Russo, Claudio

2007-01-01

The mayor pathologic hallmarks of Alzheimer's disease (AD) are senile plaque and neurofibrillary tangles. Senile plaque are primarily made up of deposits of amyloid-beta protein, a proteolytic product derived from the amyloid precursor protein (APP). APP is a transmembrane protein detected into the endoplasmic reticulum, in the Golgi apparatus, at the cell surface, recycled by endocytosis to endosomes, whose physiological function is unclear. Presenilins (PS), are a component of gamma-secretase complex that cleave alpha-CTFs (carboxy-terminal fragment), or beta-CTFs, leaving 40 or 42 amino acids amyloid-beta peptides and 58 or 56 amino acids intracellular domains (AICD). Where the amyloid-beta peptides is generated is not clear. The study of APP-PS interaction in specific cell compartments provides a good opportunity to light upon the molecular mechanisms regulating the activity of the "gamma-secretase complex," and where beta-amyloid is generated. In our study we used a biophysical assay of protein proximity: fluorescence resonance energy transfer (FRET), that can provide information about molecular interactions when two proteins are in the close proximity (<10 nm), to examine the subcellular localization and interaction between APP and PS1 in human neuroglioma cells (H4). Confocal microscopic analysis reveals extensive colocalization in different cells' compartment, and centrosomal or microtubule organizing center (MTOC) localization of APP and PS1, but not necessarily a close molecular interaction. We used FRET to determine if APP and PS1 interact at the cell centrosome. FRET data suggest a close interaction between APP and PS1 in subcellular compartments and at the centrosome of H4 cells. Using this approach we show that APP and PS1 are closely associated in the centrosomes of the H4 cell.

[Single cell gel electrophoresis of a magnesium alloy coated with beta-tricalcium phosphate].

PubMed

Hao, Yu-quan; Tan, Li-li; Yan, Ting-ting; Yan, Xiu-lin; Yang, Ke; Ai, Hong-jun

2009-10-01

To evaluate the genotoxicity of a magnesium alloy coated with beta-tricalcium phosphate (beta-TCP). Four groups were designed. In the first group, AZ31B magnesium alloy surface was coated with beta-TCP using chemical bath deposition, and in the second group magnesium alloy was tested. The other two groups were negative control (pure titanium) and positive control groups (0.5 mg/L bleomycin). Single cell gel electrophoresis was adopted to investigate genotoxicity of the alloy samples in different groups, and 60 cells from each group were analysed. Tail moment and tail DNA percentage were used as reliable indicators to show DNA damage in lymphocytes induced by every testing sample. Student-Newman-Keuls (SNK) test was used to compare results from 4 groups. There were no significant differences in tail moment and tail DNA percentage between magnesium alloy group [(0.52 +/- 0.12), (6.82 +/- 1.81)%] and magnesium alloy coated with beta-TCP group [(0.51 +/- 0.12), (6.89 +/- 1.93)%, P > 0.05]. Tail moment and tail DNA percentage in negative group were (0.47 +/- 0.14) and (6.29 +/- 1.64)%, and tail moment and tail DNA percentage in positive group were (5.17 +/- 1.23) and (22.09 +/- 4.51)%. No significant increase was found in DNA damage in lymphocytes induced by magnesium alloy coated with beta-TCP.

Mesenchymal stem cells derived from human exocrine pancreas express transcription factors implicated in beta-cell development.

PubMed

Baertschiger, Reto M; Bosco, Domenico; Morel, Philippe; Serre-Beinier, Veronique; Berney, Thierry; Buhler, Leo H; Gonelle-Gispert, Carmen

2008-07-01

Transplantation of in vitro generated islets or insulin-producing cells represents an attractive option to overcome organ shortage. The aim of this study was to isolate, expand, and characterize cells from human exocrine pancreas and analyze their potential to differentiate into beta cells. Fibroblast-like cells growing out of human exocrine tissue were characterized by flow cytometry and by their capacity to differentiate into mesenchymal cell lineages. During cell expansion and after differentiation toward beta cells, expression of transcription factors of endocrine pancreatic progenitors was analyzed by reverse transcription polymerase chain reaction. Cells emerged from 14/18 human pancreatic exocrine fractions and were expanded up to 40 population doublings. These cells displayed surface antigens similar to mesenchymal stem cells from bone marrow. A culture of these cells in adipogenic and chondrogenic differentiation media allowed differentiation into adipocyte- and chondrocyte-like cells. During expansion, cells expressed transcription factors implicated in islet development such as Isl1, Nkx2.2, Nkx6.1, nestin, Ngn3, Pdx1, and NeuroD. Activin A and hepatocyte growth factor induced an expression of insulin, glucagon, and glucokinase. Proliferating cells with characteristics of mesenchymal stem cells and endocrine progenitors were isolated from exocrine tissue. Under specific conditions, these cells expressed little insulin. Human pancreatic exocrine tissue might thus be a source of endocrine cell progenitors.

Variability and repertoire size of T-cell receptor V alpha gene segments.

PubMed

Becker, D M; Pattern, P; Chien, Y; Yokota, T; Eshhar, Z; Giedlin, M; Gascoigne, N R; Goodnow, C; Wolf, R; Arai, K

The immune system of higher organisms is composed largely of two distinct cell types, B lymphocytes and T lymphocytes, each of which is independently capable of recognizing an enormous number of distinct entities through their antigen receptors; surface immunoglobulin in the case of the former, and the T-cell receptor (TCR) in the case of the latter. In both cell types, the genes encoding the antigen receptors consist of multiple gene segments which recombine during maturation to produce many possible peptides. One striking difference between B- and T-cell recognition that has not yet been resolved by the structural data is the fact that T cells generally require a major histocompatibility determinant together with an antigen whereas, in most cases, antibodies recognize antigen alone. Recently, we and others have found that a series of TCR V beta gene sequences show conservation of many of the same residues that are conserved between heavy- and light-chain immunoglobulin V regions, and these V beta sequences are predicted to have an immunoglobulin-like secondary structure. To extend these studies, we have isolated and sequenced eight additional alpha-chain complementary cDNA clones and compared them with published sequences. Analyses of these sequences, reported here, indicate that V alpha regions have many of the characteristics of V beta gene segments but differ in that they almost always occur as cross-hybridizing gene families. We conclude that there may be very different selective pressures operating on V alpha and V beta sequences and that the V alpha repertoire may be considerably larger than that of V beta.

FcepsilonRI-alpha siRNA inhibits the antigen-induced activation of mast cells.

PubMed

Safaralizadeh, Reza; Soheili, Zahra-Soheila; Deezagi, Abdolkhaleg; Pourpak, Zahra; Samiei, Shahram; Moin, Mostafa

2009-12-01

FcepsilonRI, The high affinity receptor for IgE plays a critical role in triggering the allergic reactions. It is responsible for inducing mast cell degranulation and deliberation of allergy mediators when it is aggregated by allergen and IgE complexes. FcepsilonRI on the mast cells consists of three subunits; alpha chain directly binds IgE, beta chain and dimmer of gamma chains together mediate intracellular signaling. Cross-linking of IgE-bound FcepsilonRI on the surface of mast cells and basophils by the multivalent antigen induces release of chemical mediators. The present in vitro study was designed to investigate the effect of synthetic FcepsilonRI-alpha siRNA on the antigen-induced activation of MC/9 cells. MC/9 cells which are murine mast cells were transfected by FcepsilonRI-alpha siRNA and negative control siRNA. After 6 h, anti-DNP (Dinitrophenyl) IgE was used for the cells sensitization. Then the cells were challenged with Dinitrophenyl-Human Serum Albumin (DNP-HSA) for mast cell degranulation induction before collection of supernatants. The amount of mRNA and protein expression was measured by Real Time PCR and western blot analysis, respectively. Determination of the expression rate of FcepsilonRI-alpha on cell surface was achieved by flow cytometry. ELISA and spectrophotometry methods were used subsequently for measuring the effects of FcepsilonRI-alpha siRNA on antigen-induced histamine and beta-hexosaminidase release. FcepsilonRI-alpha siRNA treated cells showed significant decrease in FcepsilonRI-alpha mRNA and protein expression in comparison to control cells. FcepsilonRI-mediated mast cell release of beta-hexosaminidase and histamine were also inhibited. In this study it was shown that FcepsilonRI-alpha siRNA could suppress FcepsilonRI-alpha expression and inhibited degranulation and histamine release in antigen-stimulated MC/9 cells. In conclusion, knock-down of FcepsilonRI-alpha by siRNA could be a promising method for inhibition of the mast cell-mediated allergic reactions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiong, J.-P.; Stehle, T.; Zhang, R.

The structural basis for the divalent cation-dependent binding of heterodimeric alpha beta integrins to their ligands, which contain the prototypical Arg-Gly-Asp sequence, is unknown. Interaction with ligands triggers tertiary and quaternary structural rearrangements in integrins that are needed for cell signaling. Here we report the crystal structure of the extracellular segment of integrin alpha Vbeta 3 in complex with a cyclic peptide presenting the Arg-Gly-Asp sequence. The ligand binds at the major interface between the alpha V and beta 3 subunits and makes extensive contacts with both. Both tertiary and quaternary changes are observed in the presence of ligand. Themore » tertiary rearrangements take place in beta A, the ligand-binding domain of beta 3; in the complex, beta A acquires two cations, one of which contacts the ligand Asp directly and the other stabilizes the ligand-binding surface. Ligand binding induces small changes in the orientation of alpha V relative to beta 3.« less

Immunolocalization of two hydrogenosomal enzymes of Trichomonas vaginalis.

PubMed

Brugerolle, G; Bricheux, G; Coffe, G

2000-01-01

Three monoclonal antibodies specific for malic enzyme and for the alpha- and beta-subunits, respectively, of the succinyl-coenzyme A (CoA) synthetase of Trichomonas vaginalis were used to immunolocalize these proteins in the cell. All antibodies labeled the hydrogenosome matrix as determined both by immunofluorescence and by immunogold staining. There was no labeling on the cell surface or in any other cell compartment. These results support the idea that these proteins are restricted to a hydrogenosomal function and do not play a role as adhesins at the plasma membrane surface.

Covisualization by computational optical-sectioning microscopy of integrin and associated proteins at the cell membrane of living onion protoplasts

NASA Technical Reports Server (NTRS)

Gens, J. S.; Reuzeau, C.; Doolittle, K. W.; McNally, J. G.; Pickard, B. G.; Evans, M. L. (Principal Investigator)

1996-01-01

Using higher-resolution wide-field computational optical-sectioning fluorescence microscopy, the distribution of antigens recognized by antibodies against animal beta 1 integrin, fibronectin, and vitronectin has been visualized at the outer surface of enzymatically protoplasted onion epidermis cells and in depectinated cell wall fragments. On the protoplast all three antigens are colocalized in an array of small spots, as seen in raw images, in Gaussian filtered images, and in images restored by two different algorithms. Fibronectin and vitronectin but not beta 1 integrin antigenicities colocalize as puncta in comparably prepared and processed images of the wall fragments. Several control visualizations suggest considerable specifity of antibody recognition. Affinity purification of onion cell extract with the same anti-integrin used for visualization has yielded protein that separates in SDS-PAGE into two bands of about 105-110 and 115-125 kDa. These bands are again recognized by the visualization antibody, which was raised against the extracellular domain of chicken beta 1 integrin, and are also recognized by an antibody against the intracellular domain of chicken beta 1 integrin. Because beta 1 integrin is a key protein in numerous animal adhesion sites, it appears that the punctate distribution of this protein in the cell membranes of onion epidermis represents the adhesion sites long known to occur in cells of this tissue. Because vitronectin and fibronection are matrix proteins that bind to integrin in animals, the punctate occurrence of antigenically similar proteins both in the wall (matrix) and on enzymatically prepared protoplasts reinforces the concept that onion cells have adhesion sites with some similarity to certain kinds of adhesion sites in animals.

Influence of three-dimensional hyaluronic acid microenvironments on mesenchymal stem cell chondrogenesis.

PubMed

Chung, Cindy; Burdick, Jason A

2009-02-01

Mesenchymal stem cells (MSCs) are multipotent progenitor cells whose plasticity and self-renewal capacity have generated significant interest for applications in tissue engineering. The objective of this study was to investigate MSC chondrogenesis in photo-cross-linked hyaluronic acid (HA) hydrogels. Because HA is a native component of cartilage, and MSCs may interact with HA via cell surface receptors, these hydrogels could influence stem cell differentiation. In vitro and in vivo cultures of MSC-laden HA hydrogels permitted chondrogenesis, measured by the early gene expression and production of cartilage-specific matrix proteins. For in vivo culture, MSCs were encapsulated with and without transforming growth factor beta-3 (TGF-beta3) or pre-cultured for 2 weeks in chondrogenic medium before implantation. Up-regulation of type II collagen, aggrecan, and sox 9 was observed for all groups over MSCs at the time of encapsulation, and the addition of TGF-beta3 further enhanced the expression of these genes. To assess the influence of scaffold chemistry on chondrogenesis, HA hydrogels were compared with relatively inert poly(ethylene glycol) (PEG) hydrogels and showed enhanced expression of cartilage-specific markers. Differences between HA and PEG hydrogels in vivo were most noticeable for MSCs and polymer alone, indicating that hydrogel chemistry influences the commitment of MSCs to undergo chondrogenesis (e.g., approximately 43-fold up-regulation of type II collagen of MSCs in HA over PEG hydrogels). Although this study investigated only early markers of tissue regeneration, these results emphasize the importance of material cues in MSC differentiation microenvironments, potentially through interactions between scaffold materials and cell surface receptors.

Subunit assembly of hemoglobin: an important determinant of hematologic phenotype.

PubMed

Bunn, H F

1987-01-01

Hemoglobin's physiologic properties depend on the orderly assembly of its subunits in erythropoietic cells. The biosynthesis of alpha- and beta-globin polypeptide chains is normally balanced. Heme rapidly binds to the globin subunit, either during translation or shortly thereafter. The formation of the alpha beta-dimer is facilitated by electrostatic attraction of a positively charged alpha-subunit to a negatively charged beta-subunit. The alpha beta-dimer dissociates extremely slowly. The difference between the rate of dissociation of alpha beta- and alpha gamma-dimers with increasing pH explains the well-known alkaline resistance of Hb F. Two dimers combine to form the functioning alpha 2 beta 2-tetramer. This model of hemoglobin assembly explains the different levels of positively charged and negatively charged mutant hemoglobins that are encountered in heterozygotes and the effect of alpha-thalassemia and heme deficiency states in modifying the level of the variant hemoglobin as well as Hb A2. Electrostatic interactions also affect the binding of hemoglobin to the cytoplasmic surface of the red cell membrane and may underlie the formation of target cells. Enhanced binding of positively charged variants such as S and C trigger a normally dormant pathway for potassium and water loss. Thus, the positive charge on beta c is responsible for the two major contributors to the pathogenesis of Hb SC disease: increased proportion of Hb S and increased intracellular hemoglobin concentration. It is likely that electrostatic interactions play an important role in the assembly of a number of other multisubunit macromolecules, including membrane receptors, cytoskeletal proteins, and DNA binding proteins.

Inhibition of B cell proliferation by antisense DNA to both alpha and beta forms of Fc epsilon R II.

PubMed

Bhatti, L; Behle, K; Stevens, R H

1992-10-01

Epstein-Barr Virus (EBV) infection activates B lymphocyte proliferation through partially understood mechanisms, resulting in phenotypic changes, including the appearance of new antigens. One such antigen is Fc epsilon R II/CD-23 which may be relevant for B cell proliferation. We have used anti-sense oligonucleotides to study the importance of the two forms of this molecule for proliferation in the EBV-transformed, Fc epsilon R II +ve lymphoblastoid B cell line, RPMI 8866. Anti-sense oligodeoxynucleotides were generated to the two forms of Fc epsilon R II; Fc epsilon R IIa (alpha) and IIb (beta) which differ only in their intracytoplasmic domains. Addition of increasing concentrations of anti-sense oligonucleotides, ranging from 1 to 30 microM, significantly decreased cellular proliferation as measured by the incorporation of [3H]thymidine (inhibition range 8-88%). Optimum inhibition of cellular proliferation was apparent at 15 microM concentration of both anti-sense Fc epsilon R IIa and IIb (Fc epsilon R IIa, mean +/- SE = 75 +/- 7% inhibition, p less than 0.001; Fc epsilon R IIb, mean +/- SE = 71 +/- 7% inhibition, p less than 0.001). Anti-sense oligonucleotides complementary to the common part of Fc epsilon R II resulted in a similar inhibition of proliferation. Sense oligonucleotides did not induce significant inhibition. Preincubation of sense and anti-sense oligonucleotides resulted in an abrogation of proliferation inhibition. Moreover, none of these oligonucleotides had any effect on a Fc epsilon R II -ve cell line. Incubation with both anti-sense IIa and IIb resulted in additive, but not synergistic inhibition of proliferation. Addition of soluble Fc epsilon R II did not reverse inhibition of proliferation, suggesting that membrane-bound or intracellular rather than soluble Fc epsilon R II was important for the induced proliferation. Analysis of cell surface expression for Fc epsilon II indicated that while there was a pronounced effect on cell number following incubation with anti-sense oligonucleotides, surface expression of Fc epsilon R II was consistent as measured over different time points. PCR analysis revealed that while most cells expressed either the alpha or the beta form of Fc epsilon R II, EBV-transformed cell lines, particularly RPMI 8866, were found to express both alpha and beta forms simultaneously. This may constitute a mechanism whereby EBV infection confers an immortal state to the cell, resulting in its uncontrolled proliferation. Cell lines expressing only one receptor form, either alpha or beta, were unaffected after incubation with anti-sense oligonucleotides.(ABSTRACT TRUNCATED AT 400 WORDS)

Variability in Beta-Adrenergic Receptor Population in Cultured Chicken Muscle Cells

NASA Technical Reports Server (NTRS)

Young, Ronald B; Bridge, Kristin Y.; Vaughn, Jeffrey R.

1998-01-01

Investigations into expression of the beta-adrenergic receptor (bAR) in chicken skeletal muscle cells in culture were initiated because several beta-adrenergic receptor agonists are known to increase skeletal muscle protein deposition in avian and mammalian species. During initial attempts to study the bAR population on the surface of chicken skeletal muscle cells, we observed a high degree of variability that was later found to be the result of using different batches of horse serum in the cell culture media. The separation between total binding and nonspecific binding in cells grown in two serum samples was approximately two-fold The number of nuclei within multinucleated myotubes was not significantly different in cells grown in the two serum samples. To investigate whether these two sera had an effect on coupling efficiency between bAR population and cAMP production, the ability of these cells to synthesize cAMP was also assessed. Despite the two-fold difference in receptor population, the ability of these cells to synthesize cAMP was not significantly different. Because of the possible link between bAR population and muscle protein, we also determined if the quantity of the major skeletal muscle protein, myosin, was affected by conditions that so drastically affected the bAR population. The quantity of myosin heavy chain was not significantly different.

Anti-inflammatory effect of linear polarized infrared irradiation on interleukin-1beta-induced chemokine production in MH7A rheumatoid synovial cells.

PubMed

Shibata, Yasuko; Ogura, Naomi; Yamashiro, Keisuke; Takashiba, Shogo; Kondoh, Toshirou; Miyazawa, Keiji; Matsui, Masaru; Abiko, Yoshimitsu

2005-12-01

We examined the anti-inflammatory effect of infrared linear polarized light irradiation on the MH7A rheumatoid fibroblast-like synoviocytes (FLS) stimulated with the proinflammatory cytokine interleukin (IL)-1beta. Expression of messenger ribonucleic acids (mRNAs) encoding IL-8, RANTES (regulated upon activation, normal T cell expressed and secreted), growth-related gene alpha (GROalpha), and macrophage inflammatory protein-1alpha (MIP1alpha) was measured using real-time reverse transcription polymerase chain reaction, and the secreted proteins were measured in the conditioned media using enzyme-linked immunosorbent assays. We found that irradiation with linear polarized infrared light suppressed IL-1beta-induced expression of IL-8 mRNA and, correspondingly, the synthesis and release of IL-8 protein in MH7A cells. This anti-inflammatory effect was equivalent to that obtained with the glucocorticoid dexamethasone. Likewise, irradiation suppressed the IL-1beta-induced expression of RANTES and GROalpha mRNA. These results suggest that the irradiation of the areas around the articular surfaces of joints affected by rheumatoid arthritis (RA) using linear polarized light may represent a useful new approach to treatment.

A comparative study of proliferation and osteogenic differentiation of adipose-derived stem cells on akermanite and beta-TCP ceramics.

PubMed

Liu, Qihai; Cen, Lian; Yin, Shuo; Chen, Lei; Liu, Guangpeng; Chang, Jiang; Cui, Lei

2008-12-01

This study investigated the in vitro effects of akermanite, a new kind of Ca-, Mg-, Si-containing bioceramic, on the attachment, proliferation and osteogenic differentiation of human adipose-derived stem cells (hASCs). Parallel comparison of the cellular behaviors of hASCs on the akermanite was made with those on beta-tricalcium phosphate (beta-TCP). Scanning electron microscope (SEM) observation and fluorescent DiO labeling were carried out to reveal the attachment and growth of hASCs on the two ceramic surfaces, while the quantitative assay of cell proliferation with time was detected by DNA assay. Osteogenic differentiation of hASCs cultured on the akermanite and beta-TCP was assayed by ALP expression and osteocalcin (OCN) deposition, which was further confirmed by Real-time PCR analysis for markers of osteogenic differentiation. It was shown that hASCs attached and spread well on the akermanite as those on beta-TCP, and similar proliferation behaviors of hASCs were observed on the two ceramics. Both of them exhibited good compatibility to hASCs with only minor cytotoxicity as compared with the tissue culture plates. Interestingly, the osteogenic differentiation of hASCs could be enhanced on the akermanite compared with that on the beta-TCP when the culture time was extended to approximately 10 days. Thus, it can be ascertained that akermanite ceramics may serve as a potential scaffold for bone tissue engineering.

Metabolic Stress and Compromised Identity of Pancreatic Beta Cells

PubMed Central

Swisa, Avital; Glaser, Benjamin; Dor, Yuval

2017-01-01

Beta cell failure is a central feature of type 2 diabetes (T2D), but the molecular underpinnings of the process remain only partly understood. It has been suggested that beta cell failure in T2D involves massive cell death. Other studies ascribe beta cell failure to cell exhaustion, due to chronic oxidative or endoplasmic reticulum stress leading to cellular dysfunction. More recently it was proposed that beta cells in T2D may lose their differentiated identity, possibly even gaining features of other islet cell types. The loss of beta cell identity appears to be driven by glucotoxicity inhibiting the activity of key beta cell transcription factors including Pdx1, Nkx6.1, MafA and Pax6, thereby silencing beta cell genes and derepressing alternative islet cell genes. The loss of beta cell identity is at least partly reversible upon normalization of glycemia, with implications for the reversibility of T2D, although it is not known if beta cell failure reaches eventually a point of no return. In this review we discuss current evidence for metabolism-driven compromised beta cell identity, key knowledge gaps and opportunities for utility in the treatment of T2D. PMID:28270834

Metabolic Stress and Compromised Identity of Pancreatic Beta Cells.

PubMed

Swisa, Avital; Glaser, Benjamin; Dor, Yuval

2017-01-01

Beta cell failure is a central feature of type 2 diabetes (T2D), but the molecular underpinnings of the process remain only partly understood. It has been suggested that beta cell failure in T2D involves massive cell death. Other studies ascribe beta cell failure to cell exhaustion, due to chronic oxidative or endoplasmic reticulum stress leading to cellular dysfunction. More recently it was proposed that beta cells in T2D may lose their differentiated identity, possibly even gaining features of other islet cell types. The loss of beta cell identity appears to be driven by glucotoxicity inhibiting the activity of key beta cell transcription factors including Pdx1, Nkx6.1, MafA and Pax6, thereby silencing beta cell genes and derepressing alternative islet cell genes. The loss of beta cell identity is at least partly reversible upon normalization of glycemia, with implications for the reversibility of T2D, although it is not known if beta cell failure reaches eventually a point of no return. In this review we discuss current evidence for metabolism-driven compromised beta cell identity, key knowledge gaps and opportunities for utility in the treatment of T2D.

Marked differences between metalloproteases meprin A and B in substrate and peptide bond specificity.

PubMed

Bertenshaw, G P; Turk, B E; Hubbard, S J; Matters, G L; Bylander, J E; Crisman, J M; Cantley, L C; Bond, J S

2001-04-20

Meprin A and B are highly regulated, secreted, and cell-surface metalloendopeptidases that are abundantly expressed in the kidney and intestine. Meprin oligomers consist of evolutionarily related alpha and/or beta subunits. The work herein was carried out to identify bioactive peptides and proteins that are susceptible to hydrolysis by mouse meprins and kinetically characterize the hydrolysis. Gastrin-releasing peptide fragment 14-27 and gastrin 17, regulatory molecules of the gastrointestinal tract, were found to be the best peptide substrates for meprin A and B, respectively. Peptide libraries and a variety of naturally occurring peptides revealed that the meprin beta subunit has a clear preference for acidic amino acids in the P1 and P1' sites of substrates. The meprin alpha subunit selected for small (e.g. serine, alanine) or hydrophobic (e.g. phenylalanine) residues in the P1 and P1' sites, and proline was the most preferred amino acid at the P2' position. Thus, although the meprin alpha and beta subunits share 55% amino acid identity within the protease domain and are normally localized at the same tissue cell surfaces, they have very different substrate and peptide bond specificities indicating different functions. Homology models of the mouse meprin alpha and beta protease domains, based on the astacin crystal structure, revealed active site differences that can account for the marked differences in substrate specificity of the two subunits.

AKT/SGK-sensitive phosphorylation of GSK3 in the regulation of L-selectin and perforin expression as well as activation induced cell death of T-lymphocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhavsar, Shefalee K.; Merches, Katja; Bobbala, Diwakar

2012-08-17

Highlights: Black-Right-Pointing-Pointer Akt/SGK dependent phosphorylation of GSK3{alpha},{beta} regulates T lymphocytes. Black-Right-Pointing-Pointer T cells from mice expressing Akt/SGK insensitive GSK3{alpha},{beta} (gsk3{sup KI}) release less IL-2. Black-Right-Pointing-Pointer CD4{sup +} cells from gsk3{sup KI} mice express less CD62L. Black-Right-Pointing-Pointer CD8{sup +} cells from gsk3{sup KI} mice are relatively resistant to activation induced cell death. Black-Right-Pointing-Pointer Perforin expression is enhanced in gsk3{sup KI} T cells. -- Abstract: Survival and function of T-lymphocytes critically depends on phosphoinositide (PI) 3 kinase. PI3 kinase signaling includes the PKB/Akt and SGK dependent phosphorylation and thus inhibition of glycogen synthase kinase GSK3{alpha},{beta}. Lithium, a known unspecific GSK3 inhibitor protectsmore » against experimental autoimmune encephalomyelitis. The present study explored, whether Akt/SGK-dependent regulation of GSK3 activity is a determinant of T cell survival and function. Experiments were performed in mutant mice in which Akt/SGK-dependent GSK3{alpha},{beta} inhibition was disrupted by replacement of the serine residue in the respective SGK/Akt-phosphorylation consensus sequence by alanine (gsk3{sup KI}). T cells from gsk3{sup KI} mice were compared to T cells from corresponding wild type mice (gsk3{sup WT}). As a result, in gsk3{sup KI} CD4{sup +} cells surface CD62L (L-selectin) was significantly less abundant than in gsk3{sup WT} CD4{sup +} cells. Upon activation in vitro T cells from gsk3{sup KI} mice reacted with enhanced perforin production and reduced activation induced cell death. Cytokine production was rather reduced in gsk3{sup KI} T cells, suggesting that GSK3 induces effector function in CD8{sup +} T cells. In conclusion, PKB/Akt and SGK sensitive phosphorylation of GSK3{alpha},{beta} is a potent regulator of perforin expression and activation induced cell death in T lymphocytes.« less

Carbon Ion Irradiation Inhibits Glioma Cell Migration Through Downregulation of Integrin Expression

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rieken, Stefan, E-mail: Stefan.Rieken@med.uni-heidelberg.de; Habermehl, Daniel; Wuerth, Lena

2012-05-01

Purpose: To investigate the effect of carbon ion irradiation on glioma cell migration. Methods and Materials: U87 and Ln229 glioma cells were irradiated with photons and carbon ions. Migration was analyzed 24 h after irradiation. Fluorescence-activated cell sorting analysis was performed in order to quantify surface expression of integrins. Results: Single photon doses of 2 Gy and 10 Gy enhanced {alpha}{sub {nu}}{beta}{sub 3} and {alpha}{sub {nu}}{beta}{sub 5} integrin expression and caused tumor cell hypermigration on both vitronectin (Vn) and fibronectin (Fn). Compared to integrin expression in unirradiated cells, carbon ion irradiation caused decreased integrin expression and inhibited cell migration onmore » both Vn and Fn. Conclusion: Photon radiotherapy (RT) enhances the risk of tumor cell migration and subsequently promotes locoregional spread via photon induction of integrin expression. In contrast to photon RT, carbon ion RT causes decreased integrin expression and suppresses glioma cell migration on both Vn and Fn, thus promising improved local control.« less

Interactions in the aqueous phase and adsorption at the air-water interface of caseinoglycomacropeptide (GMP) and beta-lactoglobulin mixed systems.

PubMed

Martinez, María J; Sánchez, Cecilio Carrera; Patino, Juan M Rodríguez; Pilosof, Ana M R

2009-01-01

The aim of this work was to study the interactions and adsorption of caseinoglycomacropeptide (GMP) and GMP:beta-lactoglobulin (beta-lg) mixed system in the aqueous phase and at the air-water interface. The existence of associative interactions between GMP and beta-lg in the aqueous phase was investigated by dynamic light scattering, differential scanning calorimetry (DSC), fluorometry and native PAGE-electrophoresis. The surface pressure isotherm and the static and dynamic surface pressure were determined by tensiometry and surface dilatational properties. The results showed that GMP presented higher surface activity than beta-lg at a concentration of 4%wt but beta-lg showed higher film forming ability. In the mixed systems beta-lg dominated the static and dynamic surface pressure and the rheological properties of interfacial films suggesting that beta-lg hinders GMP adsorption because, in simple competition, GMP should dominate because of its higher surface activity. The surface predominance of beta-lg can be attributed to binding of GMP to beta-lg in the aqueous phase that prevents GMP adsorption on its own.

Unraveling the contribution of pancreatic beta-cell suicide in autoimmune type 1 diabetes✩

PubMed Central

Jaberi-Douraki, Majid; Schnell, Santiago; Pietropaolo, Massimo; Khadra, Anmar

2014-01-01

In type 1 diabetes, an autoimmune disease mediated by autoreactive T-cells that attack insulin-secreting pancreatic beta-cells, it has been suggested that disease progression may additionally require protective mechanisms in the target tissue to impede such auto-destructive mechanisms. We hypothesize that the autoimmune attack against beta-cells causes endoplasmic reticulum stress by forcing the remaining beta-cells to synthesize and secrete defective insulin. To rescue beta-cell from the endoplasmic reticulum stress, beta-cells activate the unfolded protein response to restore protein homeostasis and normal insulin synthesis. Here we investigate the compensatory role of unfolded protein response by developing a multi-state model of type 1 diabetes that takes into account beta-cell destruction caused by pathogenic autoreactive T-cells and apoptosis triggered by endoplasmic reticulum stress. We discuss the mechanism of unfolded protein response activation and how it counters beta-cell extinction caused by an autoimmune attack and/or irreversible damage by endoplasmic reticulum stress. Our results reveal important insights about the balance between beta-cell destruction by autoimmune attack (beta-cell homicide) and beta-cell apoptosis by endoplasmic reticulum stress (beta-cell suicide). It also provides an explanation as to why the unfolded protein response may not be a successful therapeutic target to treat type 1 diabetes. PMID:24831415

Biphasic Role of Chondroitin Sulfate in Cardiac Differentiation of Embryonic Stem Cells through Inhibition of Wnt/β-Catenin Signaling

PubMed Central

Prinz, Robert D.; Willis, Catherine M.; van Kuppevelt, Toin H.; Klüppel, Michael

2014-01-01

The glycosaminoglycan chondroitin sulfate is a critical component of proteoglycans on the cell surface and in the extracellular matrix. As such, chondroitin sulfate side chains and the sulfation balance of chondroitin play important roles in the control of signaling pathways, and have a functional importance in human disease. In contrast, very little is known about the roles of chondroitin sulfate molecules and sulfation patterns during mammalian development and cell lineage specification. Here, we report a novel biphasic role of chondroitin sulfate in the specification of the cardiac cell lineage during embryonic stem cell differentiation through modulation of Wnt/beta-catenin signaling. Lineage marker analysis demonstrates that enzymatic elimination of endogenous chondroitin sulfates leads to defects specifically in cardiac differentiation. This is accompanied by a reduction in the number of beating cardiac foci. Mechanistically, we show that endogenous chondroitin sulfate controls cardiac differentiation in a temporal biphasic manner through inhibition of the Wnt/beta-catenin pathway, a known regulatory pathway for the cardiac lineage. Treatment with a specific exogenous chondroitin sulfate, CS-E, could mimic these biphasic effects on cardiac differentiation and Wnt/beta-catenin signaling. These results establish chondroitin sulfate and its sulfation balance as important regulators of cardiac cell lineage decisions through control of the Wnt/beta-catenin pathway. Our work suggests that targeting the chondroitin biosynthesis and sulfation machinery is a novel promising avenue in regenerative strategies after heart injury. PMID:24667694

Biphasic role of chondroitin sulfate in cardiac differentiation of embryonic stem cells through inhibition of Wnt/β-catenin signaling.

PubMed

Prinz, Robert D; Willis, Catherine M; van Kuppevelt, Toin H; Klüppel, Michael

2014-01-01

The glycosaminoglycan chondroitin sulfate is a critical component of proteoglycans on the cell surface and in the extracellular matrix. As such, chondroitin sulfate side chains and the sulfation balance of chondroitin play important roles in the control of signaling pathways, and have a functional importance in human disease. In contrast, very little is known about the roles of chondroitin sulfate molecules and sulfation patterns during mammalian development and cell lineage specification. Here, we report a novel biphasic role of chondroitin sulfate in the specification of the cardiac cell lineage during embryonic stem cell differentiation through modulation of Wnt/beta-catenin signaling. Lineage marker analysis demonstrates that enzymatic elimination of endogenous chondroitin sulfates leads to defects specifically in cardiac differentiation. This is accompanied by a reduction in the number of beating cardiac foci. Mechanistically, we show that endogenous chondroitin sulfate controls cardiac differentiation in a temporal biphasic manner through inhibition of the Wnt/beta-catenin pathway, a known regulatory pathway for the cardiac lineage. Treatment with a specific exogenous chondroitin sulfate, CS-E, could mimic these biphasic effects on cardiac differentiation and Wnt/beta-catenin signaling. These results establish chondroitin sulfate and its sulfation balance as important regulators of cardiac cell lineage decisions through control of the Wnt/beta-catenin pathway. Our work suggests that targeting the chondroitin biosynthesis and sulfation machinery is a novel promising avenue in regenerative strategies after heart injury.

Beta-Adrenergic Receptor Expression in Muscle Cells

NASA Technical Reports Server (NTRS)

Young, Ronald B.; Bridge, K.; Vaughn, J. R.

1999-01-01

beta-adrenergic receptor (bAR) agonists presumably exert their physiological action on skeletal muscle cells through the bAR. Since the signal generated by the bAR is cyclic AMP (cAMP), experiments were initiated in primary chicken muscle cell cultures to determine if artificial elevation of intracellular cAMP by treatment with forskolin would alter the population of bAR expressed on the surface of muscle cells. Chicken skeletal muscle cells after 7 days in culture were employed for the experiments because muscle cells have attained a steady state with respect to muscle protein metabolism at this stage. Cells were treated with 0-10 uM forskolin for a total of three days. At the end of the 1, 2, and 3 day treatment intervals, the concentration of cAMP and the bAR population were measured. Receptor population was measured in intact muscle cell cultures as the difference between total binding of [H-3]CGP-12177 and non-specific binding of [H-3]CGP-12177 in the presence of 1 uM propranolol. Intracellular cAMP concentration was measured by radioimmunoassay. The concentration of cAMP in forskolin-treated cells increased up to 10-fold in a dose dependent manner. Increasing concentrations of forskolin also led to an increase in (beta)AR population, with a maximum increase of approximately 50% at 10 uM. This increase in (beta)AR population was apparent after only 1 day of treatment, and the pattern of increase was maintained for all 3 days of the treatment period. Thus, increasing the intracellular concentration of cAMP leads to up-regulation of (beta)AR population. Clenbuterol and isoproterenol gave similar effects on bAR population. The effect of forskolin on the quantity and apparent synthesis rate of the heavy chain of myosin (mhc) were also investigated. A maximum increase of 50% in the quantity of mhc was observed at 0.2 UM forskolin, but higher concentrations of forskolin reduced the quantity of mhc back to control levels.

Chondrocyte heterogeneity: immunohistologically defined variation of integrin expression at different sites in human fetal knees.

PubMed

Salter, D M; Godolphin, J L; Gourlay, M S

1995-04-01

During development and at maturity different forms of cartilage vary in morphology and macromolecular content. This reflects heterogeneity of chondrocyte activity, in part involving differential interactions with the adjacent extracellular matrix via specialized cell surface receptors such as integrins. We undertook an immunohistological study on a series of human fetal knee joints to assess variation in the expression of integrins by chondrocytes and potential matrix ligands in articular, epiphyseal, growth plate, and meniscal cartilage. The results show that articular chondrocytes (beta 1+, beta 5 alpha V+, alpha 1+, alpha 2+/-, alpha 5+, weakly alpha 6+, alpha V+) differed from epiphyseal (beta 1+, beta 5 alpha V+, alpha 1+/-, alpha 2+/-, alpha 5+, alpha 6+, alpha V+) growth plate (beta 1+, beta 5 alpha V+, alpha 1-, alpha 2-, alpha 5+, alpha 6+, alpha V+), and meniscal cells (beta 1+, beta 5 alpha V+, alpha 1+, strongly alpha 2+, alpha 5+, alpha 6+, alpha V+ in expression of integrin subunits. There was no expression of beta 3, beta 4, beta 6, or alpha 3 by chondrocytes. These results differ from previous reports on the expression of integrins by adult articular cartilage, where alpha 2 and alpha 6 are not seen. Variation in distribution of matrix ligands was also seen. Fibronectin, laminin and Type VI collagen were expressed in all cartilages but there was restricted expression of tenascin, ED-A and ED-B fibronectin isoforms (articular cartilage and meniscus), and vitronectin (absent from growth plate cartilage). Regulated expression of integrins by chondrocytes, associated with changes in the pericellular matrix composition, is of potential importance in control of cartilage differentiation and function in health and disease.

Permeation and gating properties of the L-type calcium channel in mouse pancreatic beta cells

PubMed Central

1993-01-01

Ba2+ currents through L-type Ca2+ channels were recorded from cell- attached patches on mouse pancreatic beta cells. In 10 mM Ba2+, single- channel currents were recorded at -70 mV, the beta cell resting membrane potential. This suggests that Ca2+ influx at negative membrane potentials may contribute to the resting intracellular Ca2+ concentration and thus to basal insulin release. Increasing external Ba2+ increased the single-channel current amplitude and shifted the current-voltage relation to more positive potentials. This voltage shift could be modeled by assuming that divalent cations both screen and bind to surface charges located at the channel mouth. The single- channel conductance was related to the bulk Ba2+ concentration by a Langmuir isotherm with a dissociation constant (Kd(gamma)) of 5.5 mM and a maximum single-channel conductance (gamma max) of 22 pS. A closer fit to the data was obtained when the barium concentration at the membrane surface was used (Kd(gamma) = 200 mM and gamma max = 47 pS), which suggests that saturation of the concentration-conductance curve may be due to saturation of the surface Ba2+ concentration. Increasing external Ba2+ also shifted the voltage dependence of ensemble currents to positive potentials, consistent with Ba2+ screening and binding to membrane surface charge associated with gating. Ensemble currents recorded with 10 mM Ca2+ activated at more positive potentials than in 10 mM Ba2+, suggesting that external Ca2+ binds more tightly to membrane surface charge associated with gating. The perforated-patch technique was used to record whole-cell currents flowing through L-type Ca2+ channels. Inward currents in 10 mM Ba2+ had a similar voltage dependence to those recorded at a physiological Ca2+ concentration (2.6 mM). BAY-K 8644 (1 microM) increased the amplitude of the ensemble and whole-cell currents but did not alter their voltage dependence. Our results suggest that the high divalent cation solutions usually used to record single L-type Ca2+ channel activity produce a positive shift in the voltage dependence of activation (approximately 32 mV in 100 mM Ba2+). PMID:7687645

Analysis of cytotoxic activity of the CD4+ T lymphocytes generated by local immunotherapy.

PubMed Central

Katsumoto, Y.; Monden, T.; Takeda, T.; Haba, A.; Ito, Y.; Wakasugi, E.; Wakasugi, T.; Sekimoto, M.; Kobayashi, T.; Shiozaki, H.; Shimano, T.; Monden, M.

1996-01-01

We previously reported that the anti-tumour effect of OK-432 is considerably enhanced by its intratumoral injection together with fibrinogen. In the present study, we generated killer T cells by culturing tumour-infiltrating lymphocytes from thyroid cancer patients who had received this local immunotherapy. Phenotypic analysis revealed that the T cells were positive for CD3+, CD4+, Leu8-, CD45RO+ and T-cell receptor (TCR)alpha beta+, as well as showing strong surface expression of HLA-DR, CD25, LFA-1 and ICAM-1. The generated CD4+ T cells secreted interferon (IFN)-gamma, tumour necrosis factor (TNF)-alpha, TNF-beta, and interleukin (IL)-6 (but not IL-4), and exhibited a high level of cytolytic activity against several tumour cell lines. The cytolytic activity of these T cells for Daudi cells was inhibited by preincubation with an anti-intercellular adhesion molecule (ICAM)-1 antibody, but not by preincubation with anti-TCR alpha beta, anti-CD2, or anti-LFA-1 antibodies. Pretreatment with anti-ICAM-1 antibody inhibited T-cell cytolytic activity, but not conjugation with target cells. In addition, incubation with immobilised anti-ICAM-1 enhanced the secretion of IFN-gamma by T cells. We conclude that ICAM-1 expressed on the effector cytotoxic CD4+ T lymphocytes delivers regulatory signals that enhance IFN-gamma secretion. PMID:8554971

N-acetylcysteine augments adenovirus-mediated gene expression in human endothelial cells by enhancing transgene transcription and virus entry.

PubMed

Jornot, L; Morris, M A; Petersen, H; Moix, I; Rochat, T

2002-01-01

It has previously been shown that oxidants reduce the efficiency of adenoviral transduction in human umbilical vein endothelial cells (HUVECs). In this study, the effect of the antioxidant N-acetylcysteine (NAC) in adenovirus-mediated gene transfer has been investigated. HUVECs were pretreated or not with NAC, and infected with E1E3-deleted adenovirus (Ad) containing the LacZ gene expressed from the RSV-LTR promoter/enhancer in the presence and absence of NAC. Transgene expression was assessed at the protein level (histochemical staining, measurement of beta-Gal activity, and western blot), mRNA level (real-time RT-PCR) and gene level (nuclear run on) 24 h and 48 h after infection. Adenoviral DNA was quantitated by real-time PCR, and cell surface expression of Coxsackie/adenovirus receptors (CAR) was determined by FACS analysis. Pretreatment of cells with NAC prior to Ad infection enhanced beta-Gal activity by two-fold due to an increase in viral DNA, which was related to increased CAR expression. When NAC was present only during the post-infection period, a five-fold increase in beta-Gal activity and LacZ gene transcriptional activity was observed. When NAC was present during both the pretreatment and the post-infection period, beta-Gal activity was further enhanced, by 15-fold. Augmentation of beta-Gal activity was paralleled by an increase in beta-Gal protein and mRNA levels. NAC did not affect the half-life of LacZ mRNA. Pretreatment with NAC prior to Ad infection enhances virus entry, while treatment with NAC post-infection increases transgene transcription. This strategy permits the use of lower adenoviral loads and thus might be helpful for gene therapy of vascular diseases. Copyright 2001 John Wiley & Sons, Ltd.

Titanium-containing zeolites and microporous molecular sieves as photovoltaic solar cells.

PubMed

Atienzar, Pedro; Valencia, Susana; Corma, Avelino; García, Hermenegildo

2007-05-14

Four titanium-containing zeolites and microporous molecular sieves differing on the crystal structure and particle size (Ti/Beta, Ti/Beta-60, TS-1 and ETS-10) are prepared, and their activity for solar cells after incorporating N3 (a commercially available ruthenium polypyridyl dye) is tested. All the zeolites exhibit photovoltaic activity, and the photoresponse is quite independent of the zeolite pore dimensions or particle size. The photoresponse increases with titanium content in the range 1-7% wt. In this way, cells are obtained that have open-circuit voltage Voc=560 mV and maximum short-circuit photocurrent density Isc=100 microA, measured for 1x1 cm2 surfaces with a solar simulator at 1000 W through and AM 1.5 filter. These values are promising and comparable to those obtained for current dye-sensitized titania solar cells.

Three-Dimensional Bioreactor Technologies for the Cocultivation of Human Mesenchymal Stem/Stromal Cells and Beta Cells

PubMed Central

Petry, Florian; Weidner, Tobias; Salzig, Denise

2018-01-01

Diabetes is a prominent health problem caused by the failure of pancreatic beta cells. One therapeutic approach is the transplantation of functional beta cells, but it is difficult to generate sufficient beta cells in vitro and to ensure these cells remain viable at the transplantation site. Beta cells suffer from hypoxia, undergo apoptosis, or are attacked by the host immune system. Human mesenchymal stem/stromal cells (hMSCs) can improve the functionality and survival of beta cells in vivo and in vitro due to direct cell contact or the secretion of trophic factors. Current cocultivation concepts with beta cells are simple and cannot exploit the favorable properties of hMSCs. Beta cells need a three-dimensional (3D) environment to function correctly, and the cocultivation setup is therefore more complex. This review discusses 3D cultivation forms (aggregates, capsules, and carriers) for hMSCs and beta cells and strategies for large-scale cultivation. We have determined process parameters that must be balanced and considered for the cocultivation of hMSCs and beta cells, and we present several bioreactor setups that are suitable for such an innovative cocultivation approach. Bioprocess engineering of the cocultivation processes is necessary to achieve successful beta cell therapy. PMID:29731775

TGF-{beta}-stimulated aberrant expression of class III {beta}-tubulin via the ERK signaling pathway in cultured retinal pigment epithelial cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chung, Eun Jee; Chun, Ji Na; Jung, Sun-Ah

2011-11-18

Highlights: Black-Right-Pointing-Pointer TGF-{beta} induces aberrant expression of {beta}III in RPE cells via the ERK pathway. Black-Right-Pointing-Pointer TGF-{beta} increases O-GlcNAc modification of {beta}III in RPE cells. Black-Right-Pointing-Pointer Mature RPE cells have the capacity to express a neuron-associated gene by TGF-{beta}. -- Abstract: The class III {beta}-tubulin isotype ({beta}{sub III}) is expressed exclusively by neurons within the normal human retina and is not present in normal retinal pigment epithelial (RPE) cells in situ or in the early phase of primary cultures. However, aberrant expression of class III {beta}-tubulin has been observed in passaged RPE cells and RPE cells with dedifferentiated morphology inmore » pathologic epiretinal membranes from idiopathic macular pucker, proliferative vitreoretinopathy (PVR) and proliferative diabetic retinopathy (PDR). Transforming growth factor-{beta} (TGF-{beta}) has been implicated in dedifferentiation of RPE cells and has a critical role in the development of proliferative vitreoretinal diseases. Here, we investigated the potential effects of TGF-{beta} on the aberrant expression of class III {beta}-tubulin and the intracellular signaling pathway mediating these changes. TGF-{beta}-induced aberrant expression and O-linked-{beta}-N-acetylglucosamine (O-GlcNac) modification of class III {beta}-tubulin in cultured RPE cells as determined using Western blotting, RT-PCR and immunocytochemistry. TGF-{beta} also stimulated phosphorylation of ERK. TGF-{beta}-induced aberrant expression of class III {beta}-tubulin was significantly reduced by pretreatment with U0126, an inhibitor of ERK phosphorylation. Our findings indicate that TGF-{beta} stimulated aberrant expression of class III {beta}-tubulin via activation of the ERK signaling pathway. These data demonstrate that mature RPE cells have the capacity to express a neuron-associated gene in response to TGF-{beta} stimulation and provide useful information towards understanding the pathogenesis of proliferative vitreoretinal diseases.« less

Whole organism high content screening identifies stimulators of pancreatic beta-cell proliferation.

PubMed

Tsuji, Naoki; Ninov, Nikolay; Delawary, Mina; Osman, Sahar; Roh, Alex S; Gut, Philipp; Stainier, Didier Y R

2014-01-01

Inducing beta-cell mass expansion in diabetic patients with the aim to restore glucose homeostasis is a promising therapeutic strategy. Although several in vitro studies have been carried out to identify modulators of beta-cell mass expansion, restoring endogenous beta-cell mass in vivo has yet to be achieved. To identify potential stimulators of beta-cell replication in vivo, we established transgenic zebrafish lines that monitor and allow the quantification of cell proliferation by using the fluorescent ubiquitylation-based cell cycle indicator (FUCCI) technology. Using these new reagents, we performed an unbiased chemical screen, and identified 20 small molecules that markedly increased beta-cell proliferation in vivo. Importantly, these structurally distinct molecules, which include clinically-approved drugs, modulate three specific signaling pathways: serotonin, retinoic acid and glucocorticoids, showing the high sensitivity and robustness of our screen. Notably, two drug classes, retinoic acid and glucocorticoids, also promoted beta-cell regeneration after beta-cell ablation. Thus, this study establishes a proof of principle for a high-throughput small molecule-screen for beta-cell proliferation in vivo, and identified compounds that stimulate beta-cell proliferation and regeneration.

Dermo beta brachytherapy with 188-Re in squamous cell carcinoma of the penis: a new therapy.

PubMed

Carrozzo, Anna Maria; Sedda, Antioco Franco; Muscardin, Luca; Donati, Pietro; Cipriani, Cesidio

2013-04-01

Squamous cell carcinoma of the penis (SCCP) is the most common penis neoplasia, favoured by phimosis, HPV infection and scleroatrophic lichen. The classic therapy is surgical with anatomic demolition, which often causes important psychological problems. Other non-demolitive therapies can be utilized, such as radiotherapy, brachytherapy and topical medical treatment. We propose a new non-invasive therapy called "Dermo beta brachytherapy (DBBT) with 188-Re" in which a synthetic inert resin-matrix containing a radioactive beta-emitting isotope is applied on the surface of the tumor lesion. A total of 15 patients with a histologically confirmed diagnosis of SCCP were enrolled for treatment (DBBT). Of the 15 patients, 12 healed, 1 was lost at follow-up and 2 did not respond to therapy. The results indicate that DBBT is an effective treatment for SCC of the penis, sparing the anatomical integrity of the organ, and allowing normal sexual activity.

TGF-beta3 is expressed in taste buds and inhibits proliferation of primary cultured taste epithelial cells.

PubMed

Nakamura, Shin-ichi; Kawai, Takayuki; Kamakura, Takashi; Ookura, Tetsuya

2010-01-01

Transforming growth factor-betas (TGF-betas), expressed in various tissues, play important roles in embryonic development and adult tissue homeostasis through their effects on cell proliferation, cell differentiation, cell death, and cell motility. However, expression of TGF-beta signaling components and their biological effect on taste epithelia has not been elucidated. We performed expression analysis of TGF-beta signaling components in taste epithelia and found that the TGF-beta3 mRNA was specifically expressed in taste buds. Type II TGF-betas receptor (TbetaR-II) mRNA was specifically expressed in the tongue epithelia including the taste epithelia. To elucidate the biological function of TGF-beta3 in taste epithelia, we performed proliferation assay with primary cultured taste epithelial cells. In the presence of TGF-beta3, percentage of BrdU-labeled cells decreased significantly, suggesting that the TGF-beta3 inhibited the proliferation of cultured taste epithelial cells through inhibiting cell-cycle entry into S phase. By quantitative reverse transcription-polymerase chain reaction assay, we found that the TGF-beta3 resulted in an increased level of expression of p15Ink4b and p21Cip1, suggesting that the TGF-beta3 inhibited the taste epithelial cell proliferation through inhibiting G1cyclin-Cdk complexes. Taken together, these results suggested that the TGF-beta3 may regulate taste epithelial cell homeostasis through controlling cell proliferation.

Persistent interferon transgene expression by RNA interference-mediated silencing of interferon receptors.

PubMed

Takahashi, Yuki; Vikman, Elin; Nishikawa, Makiya; Ando, Mitsuru; Watanabe, Yoshihiko; Takakura, Yoshinobu

2010-09-01

The in vivo half-life of interferons (IFNs) is very short, and its extension would produce a better therapeutic outcome in IFN-based therapy. Delivery of IFN genes is one solution for providing a sustained supply. IFNs have a variety of functions, including the suppression of transgene expression, through interaction with IFN receptors (IFNRs). This suppression could prevent IFNs from being expressed from vectors delivered. Silencing the expression of IFNAR and IFNGR, the receptors for type I and II IFNs, respectively, in cells expressing IFNs may prolong transgene expression of IFNs. Mouse melanoma B16-BL6 cells or mouse liver were selected as a site expressing IFNs (not a target for IFN gene therapy) and IFN-expressing plasmid DNA was delivered with or without small interfering RNA (siRNA) targeting IFNRs. Transfection of B16-BL6 cells with siRNA targeting IFNAR1 subunit (IFNAR1) resulted in the reduced expression of IFNAR on the cell surface. This silencing significantly increased the IFN-beta production in cells that were transfected with IFN-beta-expressing plasmid DNA. Similar results were obtained with the combination of IFN-gamma and IFNGR. Co-injection of IFN-beta-expressing plasmid DNA with siRNA targeting IFNAR1 into mice resulted in sustained plasma concentration of IFN-beta. These results provide experimental evidence that the RNAi-mediated silencing of IFNRs in cells expressing IFN, such as hepatocytes, is an effective approach for improving transgene expression of IFNs when their therapeutic target comprises cells other than those expressing IFNs.

A combination of cytokines EGF and CNTF protects the functional beta cell mass in mice with short-term hyperglycaemia.

PubMed

Lemper, Marie; De Groef, Sofie; Stangé, Geert; Baeyens, Luc; Heimberg, Harry

2016-09-01

When the beta cell mass or function declines beyond a critical point, hyperglycaemia arises. Little is known about the potential pathways involved in beta cell rescue. As two cytokines, epidermal growth factor (EGF) and ciliary neurotrophic factor (CNTF), restored a functional beta cell mass in mice with long-term hyperglycaemia by reprogramming acinar cells that transiently expressed neurogenin 3 (NGN3), the current study assesses the effect of these cytokines on the functional beta cell mass after an acute chemical toxic insult. Glycaemia and insulin levels, pro-endocrine gene expression and beta cell origin, as well as the role of signal transducer and activator of transcription 3 (STAT3) signalling, were assessed in EGF+CNTF-treated mice following acute hyperglycaemia. The mice were hyperglycaemic 1 day following i.v. injection of the beta cell toxin alloxan, when the two cytokines were applied. One week later, 68.6 ± 4.6% of the mice had responded to the cytokine treatment and increased their insulin(+) cell number to 30% that of normoglycaemic control mice, resulting in restoration of euglycaemia. Although insulin(-) NGN3(+) cells appeared following acute EGF+CNTF treatment, genetic lineage tracing showed that the majority of the insulin(+) cells originated from pre-existing beta cells. Beta cell rescue by EGF+CNTF depends on glycaemia rather than on STAT3-induced NGN3 expression in acinar cells. In adult mice, EGF+CNTF allows the rescue of beta cells in distress when treatment is given shortly after the diabetogenic insult. The rescued beta cells restore a functional beta cell mass able to control normal blood glucose levels. These findings may provide new insights into compensatory pathways activated early after beta cell loss.

Effects of sequential artificial tear and cyclosporine emulsion therapy on conjunctival goblet cell density and transforming growth factor-beta2 production.

PubMed

Pflugfelder, Stephen C; De Paiva, Cintia S; Villarreal, Arturo L; Stern, Michael E

2008-01-01

To evaluate the effects of sequential treatment with artificial tears and cyclosporine emulsion on conjunctival goblet cell density and production of transforming growth factor (TGF)-beta2 in patients with dry eye disease. Patients with dry eye disease (N = 6) defined by an Ocular Surface Disease Index symptom score >or=25, Schirmer test 1 <10 mm, and corneal fluorescein and conjunctival lissamine green staining scores >or=3 were treated with artificial tears (Refresh Plus; Allergan, Irvine, CA) 4 times a day for 4 weeks, followed by 0.05% cyclosporine emulsion (Restasis; Allergan) twice a day for 12 weeks. Impression cytology was performed on the bulbar conjunctiva of both eyes at baseline, after artificial tear therapy, and after 6 and 12 weeks of cyclosporine therapy. Goblet cells were counted in 5 representative microscopic fields per membrane in those taken from the temporal and inferior bulbar conjunctiva of the worse eye, and membranes taken from the fellow eye were immunostained for TGF-beta2. There were no differences in mean goblet cell density between baseline and 4 weeks of artificial tears in the temporal and inferior bulbar specimens. After 6 weeks of cyclosporine emulsion, goblet cell density was significantly greater than baseline and artificial tears in the inferior bulbar conjunctiva (P < 0.01). After 12 weeks of cyclosporine emulsion, goblet cell density was significantly greater than baseline and artificial tears in both temporal and inferior bulbar sites (P < 0.01). The number of TGF-beta2-positive goblet cells was also noted to increase after 6 and 12 weeks of cyclosporine therapy (P < 0.001). Cyclosporine emulsion, but not artificial tears, increases goblet cell density and production of the immunoregulatory factor TGF-beta2 in the bulbar conjunctiva in patients with dry eye.

4-1BB regulates NKG2D costimulation in human cord blood CD8+ T cells.

PubMed

Kim, Young-June; Han, Myung-Kwan; Broxmeyer, Hal E

2008-02-01

Ligation of NKG2D, a potent costimulatory receptor, can be either beneficial or detrimental to CD8(+) cytotoxic T cell (CTL) responses. Factors for these diverse NKG2D effects remain elusive. In this study, we demonstrate that 4-1BB, another costimulatory receptor, is an essential regulator of NKG2D in CD8(+) T cells. Costimulation of NKG2D caused down-modulation of NKG2D, but induced 4-1BB expression on the cell surface, even in the presence of TGF-beta1, which inhibits 4-1BB expression. Resulting NKG2D(-)4-1BB(+) cells were activated but still in an immature state with low cytotoxic activity. However, subsequent 4-1BB costimulation induced cytotoxic activity and restored down-modulated NKG2D. The cytotoxic activity and NKG2D expression induced by 4-1BB on NKG2D(+)4-1BB(+) cells were refractory to TGF-beta1 down-modulation. Such 4-1BB effects were enhanced by IL-12. In contrast, in the presence of IL-4, 4-1BB effects were abolished because IL-4 down-modulated NKG2D and 4-1BB expression in cooperation with TGF-beta1, generating another CD8(+) T-cell type lacking both NKG2D and 4-1BB. These NKG2D(-)4-1BB(-) cells were inert and unable to gain cytotoxic activity. Our results suggest that 4-1BB plays a critical role in protecting NKG2D from TGF-beta1-mediated down-modulation. Co-expression of NKG2D and 4-1BB may represent an important biomarker for defining competency of tumor infiltrating CD8(+) T cells.

Betaglycan expression is transcriptionally up-regulated during skeletal muscle differentiation. Cloning of murine betaglycan gene promoter and its modulation by MyoD, retinoic acid, and transforming growth factor-beta.

PubMed

Lopez-Casillas, Fernando; Riquelme, Cecilia; Perez-Kato, Yoshiaki; Ponce-Castaneda, M Veronica; Osses, Nelson; Esparza-Lopez, Jose; Gonzalez-Nunez, Gerardo; Cabello-Verrugio, Claudio; Mendoza, Valentin; Troncoso, Victor; Brandan, Enrique

2003-01-03

Betaglycan is a membrane-anchored proteoglycan co-receptor that binds transforming growth factor beta (TGF-beta) via its core protein and basic fibroblast growth factor through its glycosaminoglycan chains. In this study we evaluated the expression of betaglycan during the C(2)C(12) skeletal muscle differentiation. Betaglycan expression, as determined by Northern and Western blot, was up-regulated during the conversion of myoblasts to myotubes. The mouse betaglycan gene promoter was cloned, and its sequence showed putative binding sites for SP1, Smad3, Smad4, muscle regulatory factor elements such as MyoD and MEF2, and retinoic acid receptor. Transcriptional activity of the mouse betaglycan promoter reporter was also up-regulated in differentiating C(2)C(12) cells. We found that MyoD, but not myogenin, stimulated this transcriptional activity even in the presence of high serum. Betaglycan promoter activity was increased by RA and inhibited by the three isoforms of TGF-beta. On the other hand, basic fibroblast growth factor, BMP-2, and hepatocyte growth factor/scatter factor, which are inhibitors of myogenesis, had little effect. In myotubes, up-regulated betaglycan was also detectable by TGF-beta affinity labeling and immunofluorescence microscopy studies. The latter indicated that betaglycan was localized both on the cell surface and in the ECM. Forced expression of betaglycan in C(2)C(12) myoblasts increases their responsiveness to TGF-beta2, suggesting that it performs a TGF-beta presentation function in this cell lineage. These results indicate that betaglycan expression is up-regulated during myogenesis and that MyoD and RA modulate its expression by a mechanism that is independent of myogenin.

Studies of insulin secretory responses and of arachidonic acid incorporation into phospholipids of stably transfected insulinoma cells that overexpress group VIA phospholipase A2 (iPLA2beta ) indicate a signaling rather than a housekeeping role for iPLA2beta.

PubMed

Ma, Z; Ramanadham, S; Wohltmann, M; Bohrer, A; Hsu, F F; Turk, J

2001-04-20

A cytosolic 84-kDa group VIA phospholipase A(2) (iPLA(2)beta) that does not require Ca(2+) for catalysis has been cloned from several sources, including rat and human pancreatic islet beta-cells and murine P388D1 cells. Many potential iPLA(2)beta functions have been proposed, including a signaling role in beta-cell insulin secretion and a role in generating lysophosphatidylcholine acceptors for arachidonic acid incorporation into P388D1 cell phosphatidylcholine (PC). Proposals for iPLA(2)beta function rest in part on effects of inhibiting iPLA(2)beta activity with a bromoenol lactone (BEL) suicide substrate, but BEL also inhibits phosphatidate phosphohydrolase-1 and a group VIB phospholipase A(2). Manipulation of iPLA(2)beta expression by molecular biologic means is an alternative approach to study iPLA(2)beta functions, and we have used a retroviral construct containing iPLA(2)beta cDNA to prepare two INS-1 insulinoma cell clonal lines that stably overexpress iPLA(2)beta. Compared with parental INS-1 cells or cells transfected with empty vector, both iPLA(2)beta-overexpressing lines exhibit amplified insulin secretory responses to glucose and cAMP-elevating agents, and BEL substantially attenuates stimulated secretion. Electrospray ionization mass spectrometric analyses of arachidonic acid incorporation into INS-1 cell PC indicate that neither overexpression nor inhibition of iPLA(2)beta affects the rate or extent of this process in INS-1 cells. Immunocytofluorescence studies with antibodies directed against iPLA(2)beta indicate that cAMP-elevating agents increase perinuclear fluorescence in INS-1 cells, suggesting that iPLA(2)beta associates with nuclei. These studies are more consistent with a signaling than with a housekeeping role for iPLA(2)beta in insulin-secreting beta-cells.

Different susceptibility of rat pancreatic alpha and beta cells to hypoxia.

PubMed

Bloch, Konstantin; Vennäng, Julia; Lazard, Daniel; Vardi, Pnina

2012-06-01

Insulin-producing beta cells are known to be highly susceptible to hypoxia, which is a major factor in their destruction after pancreatic islet transplantation. However, whether the glucagon-producing pancreatic islet alpha cells are sensitive to hypoxia is not known. Our objective was to compare the sensitivity of alpha and beta cells to hypoxia. Isolated rat pancreatic islets were exposed to hypoxia (1% oxygen, 94% N(2), 5% CO(2)) for 3 days. The viability of the alpha and beta cells, as well as the stimulus-specific secretion of glucagon and insulin, was evaluated. A quantitative analysis of the proportion of beta to alpha cells indicated that, under normoxic conditions, islet cells were composed mainly of beta cells (87 ± 3%) with only 13 ± 3% alpha cells. Instead, hypoxia treatment significantly increased the proportion of alpha cells (40 ± 13%) and decreased the proportion of beta cells to 60 ± 13%. Using the fluorescent TUNEL assay we found that only a few percent of beta cells and alpha cells were apoptotic in normoxia. In contrast, hypoxia induced an abundance of apoptotic beta cells (61 ± 22%) and had no effect on the level of apoptosis in alpha cells. In conclusion, this study demonstrates that hypoxia results in severe functional abnormality in both beta and alpha cells while alpha cells display significantly decreased rate of apoptosis compared to intensive apoptotic injury of beta cells. These findings have implications for the understanding of the possible role of hypoxia in the pathophysiology of diabetes.

A Novel Di-Leucine Motif at the N-Terminus of Human Organic Solute Transporter Beta Is Essential for Protein Association and Membrane Localization.

PubMed

Xu, Shuhua; Soroka, Carol J; Sun, An-Qiang; Backos, Donald S; Mennone, Albert; Suchy, Frederick J; Boyer, James L

2016-01-01

The heteromeric membrane protein Organic Solute Transporter alpha/beta is the major bile acid efflux transporter in the intestine. Physical association of its alpha and beta subunits is essential for their polarized basolateral membrane localization and function in the transport of bile acids and other organic solutes. We identified a highly conserved acidic dileucine motif (-EL20L21EE) at the extracellular amino-tail of organic solute transporter beta from multiple species. To characterize the role of this protein interacting domain in the association of the human beta and alpha subunits and in membrane localization of the transporter, Leu20 and Leu21 on the amino-tail of human organic solute transporter beta were replaced with alanines by site-directed mutagenesis. Co-immunoprecipitation study in HEK293 cells demonstrated that substitution of the leucine residues with alanines prevented the interaction of the human beta mutant with the alpha subunit. Membrane biotinylation demonstrated that the LL/AA mutant eliminated membrane expression of both subunits. Computational-based modelling of human organic solute transporter beta suggested that the LL/AA mutation substantially alters both the structure and lipophilicity of the surface, thereby not only affecting the interaction with the alpha subunit but also possibly impacting the capacity of the beta subunit to traffick through the cell and interact with the membrane. In summary, our findings indicate that the dileucine motif in the extracellular N-terminal region of human organic solute transporter beta subunit plays a critical role in the association with the alpha subunit and in its polarized plasma membrane localization.

[Increase of beta 2-microglobulin in drug addicts with anti-HIV antibodies and high risk of AIDS].

PubMed

D'Angelo, G; Giardini, C; Zanco, M D; Calvano, D; Crovetti, G; De Filippo, C

1991-01-01

The beta 2-Microglobulin is a polypeptide present on the surface membrane of both B and T cells and is integrated into the structure of HLA antigenes. The beta 2-Microglobulin concentration have been used as a reliable indicator of glomerular and tubular function of the kidney. Increased serum concentration of beta 2-Microglobulin are observed also in lymphoproliferative disorders with high cell proliferation rates. More recently, increased concentration of beta 2-Microglobulin was shown in patients with anti-HIV antibodies with or without symptomatic AIDS. We have determined beta 2-Microglobulin in 61 subjects: 40 between the ages of 25 and 35 and seemingly healthy, 21 patients between the ages of 22 and 32 and intravenous drug abuser with anti-HIV antibodies and at high-risk for AIDS. In all subjects we have tested: BUN, creatinine, beta 2-Microglobulin and T4/T8 ratio. In 40 subjects as normal controls, beta 2-Microglobulin average was means = 1.07 mg/L (SD = 0.39), T4/T8 ratio average: means = 1.06 (SD = 0.119). In 21 patients drug abuser with anti-HIV antibodies, the beta 2-Microglobulin average was cleanly increased: means = 4.72 mg/L (SD = 2.23), the T4/T8 ratio average cleanly decreased: means = 0.54 (SD = 0.21). We believe the beta 2-Microglobulin quantitation, even if not specific for patient with symptomatic AIDS, used in conjunction with other laboratory tests, principally T4/T8 ratio, will be a useful marker for recognizing persons with possible asymptomatic AIDS who are members of populations known to be at high-risk for AIDS.

HES6 reverses nuclear reprogramming of insulin-producing cells following cell fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ball, Andrew J.; Abrahamsson, Annelie E.; Tyrberg, Bjoern

2007-04-06

To examine the mechanism by which growth-stimulated pancreatic {beta}-cells dedifferentiate, somatic cell fusions were performed between MIN6, a highly differentiated mouse insulinoma, and {beta}lox5, a cell line derived from human {beta}-cells which progressively dedifferentiated in culture. MIN6/{beta}lox5 somatic cells hybrids underwent silencing of insulin expression and a marked decline in PDX1, NeuroD, and MafA, indicating that {beta}lox5 expresses a dominant transacting factor(s) that represses {beta}-cell differentiation. Expression of Hes1, which inhibits endocrine differentiation was higher in hybrid cells than in parental MIN6 cells. Hes6, a repressor of Hes1, was highly expressed in primary {beta}-cells as well as MIN6, but wasmore » repressed in hybrids. Hes6 overexpression using a retroviral vector led to a decrease in Hes1 levels, an increase in {beta}-cell transcription factors and partial restoration of insulin expression. We conclude that the balance of Notch activators and inhibitors may play an important role in maintaining the {beta}-cell differentiated state.« less

Fibronectin regulates the activation of THP-1 cells by TGF-beta1.

PubMed

Wang, A C; Fu, L

2001-03-01

To determine how fibronectin regulates the immunomodulatory effects of transforming growth factor (TGF)-beta on THP-1 cells. THP-1 monocytic cell line. THP-1 cells were primed for 48 h in the presence or absence of 250 pM TGF-beta1. Assays or assessments carried out, together with statistical test applied. We found that adherence to fibronectin dramatically modulates the effects of TGF-beta1 on the human monocytic cell line THP-1. TGF-beta did not significantly affect constitutive interleukin (IL)-8 secretion or IL-1beta-induced IL-8 secretion from suspended cells. In contrast, TGF-beta stimulated IL-8 secretion as well as augmented IL-1beta-induced IL-8 secretion from adherent cells. The differential effects of TGF-beta1 on IL-8 secretion from suspended and adherent cells could not be explained by differences in IL-1 receptor antagonist production. The effects of fibronectin on TGF-beta1 induced IL-8 secretion from THP-1 cells were mimicked by adhesion to immobilized anti-a4beta1 integrin antibody and to a fibronectin fragment containing the CS-1 domain. These results indicate that alpha4beta1-mediated adhesion to fibronectin may play a key role during inflammation by profoundly influencing the effects of TGF-beta1 on monocytes.

Direct ethanol production from barley beta-glucan by sake yeast displaying Aspergillus oryzae beta-glucosidase and endoglucanase.

PubMed

Kotaka, Atsushi; Bando, Hiroki; Kaya, Masahiko; Kato-Murai, Michiko; Kuroda, Kouichi; Sahara, Hiroshi; Hata, Yoji; Kondo, Akihiko; Ueda, Mitsuyoshi

2008-06-01

Three beta-glucosidase- and two endoglucanase-encoding genes were cloned from Aspergillus oryzae, and their gene products were displayed on the cell surface of the sake yeast, Saccharomyces cerevisiae GRI-117-UK. GRI-117-UK/pUDB7 displaying beta-glucosidase AO090009000356 showed the highest activity against various substrates and efficiently produced ethanol from cellobiose. On the other hand, GRI-117-UK/pUDCB displaying endoglucanase AO090010000314 efficiently degraded barley beta-glucan to glucose and smaller cellooligosaccharides. GRI-117-UK/pUDB7CB codisplaying both beta-glucosidase AO090009000356 and endoglucanase AO090010000314 was constructed. When direct ethanol fermentation from 20 g/l barley beta-glucan as a model substrate was performed with the codisplaying strain, the ethanol concentration reached 7.94 g/l after 24 h of fermentation. The conversion ratio of ethanol from beta-glucan was 69.6% of the theoretical ethanol concentration produced from 20 g/l barley beta-glucan. These results showed that sake yeast displaying A. oryzae cellulolytic enzymes can be used to produce ethanol from cellulosic materials. Our constructs have higher ethanol production potential than the laboratory constructs previously reported.

Urocortin 3 Marks Mature Human Primary and Embryonic Stem Cell-Derived Pancreatic Alpha and Beta Cells

PubMed Central

van der Meulen, Talitha; Xie, Ruiyu; Kelly, Olivia G.; Vale, Wylie W.; Sander, Maike; Huising, Mark O.

2012-01-01

The peptide hormone Urocortin 3 (Ucn 3) is abundantly and exclusively expressed in mouse pancreatic beta cells where it regulates insulin secretion. Here we demonstrate that Ucn 3 first appears at embryonic day (E) 17.5 and, from approximately postnatal day (p) 7 and onwards throughout adult life, becomes a unifying and exclusive feature of mouse beta cells. These observations identify Ucn 3 as a potential beta cell maturation marker. To determine whether Ucn 3 is similarly restricted to beta cells in humans, we conducted comprehensive immunohistochemistry and gene expression experiments on macaque and human pancreas and sorted primary human islet cells. This revealed that Ucn 3 is not restricted to the beta cell lineage in primates, but is also expressed in alpha cells. To substantiate these findings, we analyzed human embryonic stem cell (hESC)-derived pancreatic endoderm that differentiates into mature endocrine cells upon engraftment in mice. Ucn 3 expression in hESC-derived grafts increased robustly upon differentiation into mature endocrine cells and localized to both alpha and beta cells. Collectively, these observations confirm that Ucn 3 is expressed in adult beta cells in both mouse and human and appears late in beta cell differentiation. Expression of Pdx1, Nkx6.1 and PC1/3 in hESC-derived Ucn 3+ beta cells supports this. However, the expression of Ucn 3 in primary and hESC-derived alpha cells demonstrates that human Ucn 3 is not exclusive to the beta cell lineage but is a general marker for both the alpha and beta cell lineages. Ucn 3+ hESC-derived alpha cells do not express Nkx6.1, Pdx1 or PC1/3 in agreement with the presence of a separate population of Ucn 3+ alpha cells. Our study highlights important species differences in Ucn 3 expression, which have implications for its utility as a marker to identify mature beta cells in (re)programming strategies. PMID:23251699

The Tregs' world according to GARP.

PubMed

Battaglia, Manuela; Roncarolo, Maria Grazia

2009-12-01

Naturally occurring CD4+CD25(high) regulatory T cells (nTreg) are essential for maintaining tolerance. FOXP3 has been established as a molecular marker of nTreg; however, FOXP3 cannot be used as a reliable marker for bona fide human nTreg since effector T cells also up-regulate FOXP3 expression upon activation. Despite the important function of nTreg, the underlying molecular mechanisms of nTreg-mediated suppression are far from defined. Previous studies have demonstrated that the TGF-beta latency-associated peptide (LAP) is expressed on the surface of nTreg, and that immunosuppression can be mediated by membrane TGF-beta; however, it remains unknown how LAP is bound to nTreg and what is the functional significance of its selective expression on activated nTreg. The nTreg's world may now change according to GARP, an orphan toll-like receptor composed of leucine-rich repeats. In this issue of the European Journal of Immunology, a study provides further demonstration that GARP is selectively expressed only in activated human nTreg and nTreg cell clones but not in activated effector T cells, confirming GARP as a bona fide nTreg marker. In addition, GARP binds directly to LAP; yet, GARP over-expression is insufficient to induce modification of latent TGF-beta into active TGF-beta further clarifying its role in nTreg-mediated suppression.

Inhibin/activin-betaC and -betaE subunits in the Ishikawa human endometrial adenocarcinoma cell line.

PubMed

Kimmich, Tanja; Brüning, Ansgar; Käufl, Stephanie D; Makovitzky, Josef; Kuhn, Christina; Jeschke, Udo; Friese, Klaus; Mylonas, Ioannis

2010-08-01

Inhibins and activins are important regulators of the female reproductive system. Recently, two novel inhibin subunits, named betaC and betaE, have been identified and shown to be expressed in several human tissues. However, only limited data on the expression of these novel inhibin subunits in normal human endometrial tissue and endometrial adenocarcinoma cell lines exist. Samples of proliferative and secretory human endometrium were obtained from five premenopausal, non-pregnant patients undergoing gynecological surgery for benign diseases. Normal endometrial tissue and Ishikawa endometrial adenocarcinoma cell lines were analyzed by immunohistochemistry, immunofluorescence and RT-PCR. Expression of the inhibin betaC and betaE subunits could be demonstrated at the protein level by means of immunohistochemical evaluation and at the transcriptional level by establishing a betaC- and betaE-specific RT-PCR analysis in normal human endometrial tissue and the parental Ishikawa cell line. Interestingly, in a highly de-differentiated subclone of the Ishikawa cell line lacking estrogen receptor expression, the expression of the inhibin-betaC subunit appeared strongly reduced. Here, we show for the first time that the novel inhibin/activin-betaC and -betaE subunits are expressed in normal human endometrium and the estrogen receptor positive human endometrial carcinoma cell line Ishikawa using RT-PCR and immunohistochemical detection methods. Interestingly, the Ishikawa minus cell line (lacking estrogen receptor expression) demonstrated no to minimal expression of the betaC subunit as observed with immunofluorescence and RT-PCR, suggesting a possible hormone- dependency of this subunit in human endometrial cancer cells. Moreover, because the Ishikawa cell line minus is thought to be a more malignant endometrial cell line than its estrogen receptor positive counterpart, inhibin-betaC subunit might be substantially involved in the pathogenesis and malignant transformation in human endometrium.

Normal flora: living vehicles for non-invasive protein drug delivery.

PubMed

Shao, Jun; Kaushal, Gagan

2004-11-22

Feasibility to use probiotic bacteria as a living protein delivery system through oral route was assessed in vitro. Lactococcus lactis transformed with a plasmid to express and secret beta-lactamase was used to deliver beta-lactamase through Caco-2 monolayer, an intestine epithelium. Transport of beta-lactamase through Caco-2 monolayer was carried out in the transwells. The viability and integrity of the cell monolayers co-cultured with L. lactis was examined by trypan blue exclusion method and by measuring the transport of mannitol and propranolol as well as the transepithelial electrical resistance (TEER). Results show that it is feasible to use cell culture technique to evaluate the drug delivery by normal flora. The transport rate of beta-lactamase when delivered by L. lactis was 2.0 +/- 0.1 x 10(-2)h(-1) (n = 9) and through free solution form was 1.0 +/- 0.1 x 10(-2)h-1. When co-cultured with L. lactis, Caco-2 cell viability decreased to 98, 96, and 94% at 6, 8, and 10h, respectively. Transport of mannitol through Caco-2 cell monolayer was significantly increased and the transport of propranolol through Caco-2 cell monolayer was significantly decreased in the presence of L. lactis. Increase in the amount of protein delivered is probably due to the concentrate of the protein by L. lactis on the monolayer (absorption surface) and the opening of the tight junction of Caco-2 monolayer by L. lactis. copyright 2004 Elsevier B.V.

Receptor-binding region in human choriogonadotropin/lutropin. beta. subunit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keutmann, H.T.; Charlesworth, M.C.; Mason, K.A.

1987-04-01

Synthetic fragments have not been widely used thus far to evaluate structure-activity relations in the glycoprotein hormones. The authors prepared a series of peptides representing the intercysteine loop sequence (residues 38-57) in human choriogonadotropin (hCG) and lutropin (hLH) ..beta.. subunits, anticipating that it might be oriented toward the surface and accessible to receptors. The peptides were characterized chemically and tested for bioactivity by binding to rat ovarian membrane receptor and stimulation of Leydig cell testosterone production. The hCG..beta..-(38-57) and hLH..beta..-(38-57) peptides inhibited binding of /sup 125/I-labeled hCG half-maximally at 1.51 x 10/sup -4/ and 2.03 x 10/sup -5/ M, respectively,more » while other peptide hormones and fragments from elsewhere in the ..beta.. subunit were inactive. Both peptides stimulated testosterone production, with half-maximal responses at 3.55 x 10/sup -5/ M (hCG) and 2.18 x 10/sup -5/ M (hLH). By radioimmunoassay with an antibody to thyroglobulin-conjugated hCG..beta..-(38-57) peptide, native hCG and ..beta.. subunit were highly reactive, as were the reduced and carboxymethylated subunit and peptide. These results indicate that the 38-57 region of ..beta.. subunit is exposed on the surface and constitutes a component in the receptor-binding domain for hCG and hLH. A region of amphipathic-helical structure in the 38-57 sequence may promote hormone-receptor interactions in a manner proposed for several other peptide hormones.« less

Production of hyaline-like cartilage by bone marrow mesenchymal stem cells in a self-assembly model.

PubMed

Elder, Steven H; Cooley, Avery J; Borazjani, Ali; Sowell, Brittany L; To, Harrison; Tran, Scott C

2009-10-01

A scaffoldless or self-assembly approach to cartilage tissue engineering has been used to produce hyaline cartilage from bone marrow-derived mesenchymal stem cells (bMSCs), but the mechanical properties of such engineered cartilage and the effects the transforming growth factor (TGF) isoform have not been fully explored. This study employs a cell culture insert model to produce tissue-engineered cartilage using bMSCs. Neonatal pig bMSCs were isolated by plastic adherence and expanded in monolayer before being seeded into porous transwell inserts and cultured for 4 or 8 weeks in defined chondrogenic media containing either TGF-beta1 or TGF-beta3. Following biomechanical evaluation in confined compression, colorimetric dimethyl methylene blue and Sircol dye-binding assays were used to analyze glycosaminoglycan (GAG) and collagen contents, respectively. Histological sections were stained with toluidine blue for proteoglycans and with picrosirius red to reveal collagen orientation, and immunostained for detection of collagen types I and II. Neocartilage increased in thickness, collagen, and GAG content between 4 and 8 weeks. Proteoglycan concentration increased with depth from the top surface. The tissue contained much more collagen type II than type I, and there was a consistent pattern of collagen alignment. TGF-beta1-treated and TGF-beta3-treated constructs were similar at 4 weeks, but 8-week TGF-beta1 constructs had a higher aggregate modulus and GAG content compared to TGF-beta3. These results demonstrate that bMSCs can generate functional hyaline-like cartilage through a self-assembling process.

Optimization of Methods for Articular Cartilage Surface Tissue Engineering: Cell Density and Transforming Growth Factor Beta Are Critical for Self-Assembly and Lubricin Secretion.

PubMed

Iwasa, Kenjiro; Reddi, A Hari

2017-07-01

Lubricin/superficial zone protein (SZP)/proteoglycan4 (PRG4) plays an important role in boundary lubrication in articular cartilage. Lubricin is secreted by superficial zone chondrocytes and synoviocytes of the synovium. The specific objective of this investigation is to optimize the methods for tissue engineering of articular cartilage surface. The aim of this study is to investigate the effect of cell density on the self-assembly of superficial zone chondrocytes and lubricin secretion as a functional assessment. Superficial zone chondrocytes were cultivated as a monolayer at low, medium, and high densities. Chondrocytes at the three different densities were treated with transforming growth factor beta (TGF-β)1 twice a week or daily, and the accumulated lubricin in the culture medium was analyzed by immunoblots and quantitated by enzyme-linked immunosorbent assay (ELISA). Cell numbers in low and medium densities were increased by TGF-β1; whereas cell numbers in high-density cell cultures were decreased by twice-a-week treatment of TGF-β1. On the other hand, the cell numbers were maintained by daily TGF-β treatment. Immunoblots and quantitation of lubricin by ELISA analysis indicated that TGF-β1 stimulated lubricin secretion by superficial zone chondrocytes at all densities with twice-a-week TGF-β treatment. It is noteworthy that the daily treatment of TGF-β1 increased lubricin much higher compared with twice-a-week treatment. These data demonstrate that daily treatment is optimal for the TGF-β1 response in a higher density of monolayer cultures. These findings have implications for self-assembly of surface zone chondrocytes of articular cartilage for application in tissue engineering of articular cartilage surface.

Effects of exendin-4 on glucose tolerance, insulin secretion, and beta-cell proliferation depend on treatment dose, treatment duration and meal contents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arakawa, Masayuki; Ebato, Chie; Mita, Tomoya

2009-12-18

Beta-cell proliferation is regulated by various metabolic demands including peripheral insulin resistance, obesity, and hyperglycemia. In addition to enhancement of glucose-induced insulin secretion, agonists for glucagon-like peptide-1 receptor (GLP-1R) stimulate proliferation and inhibit apoptosis of beta-cells, thereby probably preserve beta-cell mass. To evaluate the beta-cell preserving actions of GLP-1R agonists, we assessed the acute and chronic effects of exendin-4 on beta-cell proliferation, mass and glucose tolerance in C57BL/6J mice under various conditions. Short-term administration of high-dose exendin-4 transiently stimulated beta-cell proliferation. Comparative transcriptomic analysis showed upregulation of IGF-1 receptor and its downstream effectors in islets. Treatment of mice with exendin-4more » daily for 4 weeks (long-term administration) and feeding high-fat diet resulted in significant inhibition of weight gain and improvement of glucose tolerance with reduced insulin secretion and beta-cell mass. These findings suggest that long-term GLP-1 treatment results in insulin sensitization of peripheral organs, rather than enhancement of beta-cell proliferation and function, particularly when animals are fed high-fat diet. Thus, the effects of exendin-4 on glucose tolerance, insulin secretion, and beta-cell proliferation largely depend on treatment dose, duration of treatment and meal contents. While GLP-1 enhances proliferation of beta-cells in some diabetic mice models, our results suggest that GLP-1 stimulates beta-cell growth only when expansion of beta-cell mass is required to meet metabolic demands.« less

A Combined NMR-Computational Study of the Interaction between Influenza Virus Hemagglutinin and Sialic Derivatives from Human and Avian Receptors on the Surface of Transfected Cells.

PubMed

Vasile, Francesca; Panigada, Maddalena; Siccardi, Antonio; Potenza, Donatella; Tiana, Guido

2018-04-24

The development of small-molecule inhibitors of influenza virus Hemagglutinin could be relevant to the opposition of the diffusion of new pandemic viruses. In this work, we made use of Nuclear Magnetic Resonance (NMR) spectroscopy to study the interaction between two derivatives of sialic acid, Neu5Ac-α-(2,6)-Gal-β-(1⁻4)-GlcNAc and Neu5Ac-α-(2,3)-Gal-β-(1⁻4)-GlcNAc, and hemagglutinin directly expressed on the surface of recombinant human cells. We analyzed the interaction of these trisaccharides with 293T cells transfected with the H5 and H1 variants of hemagglutinin, which thus retain their native trimeric conformation in such a realistic environment. By exploiting the magnetization transfer between the protein and the ligand, we obtained evidence of the binding event, and identified the epitope. We analyzed the conformational features of the glycans with an approach combining NMR spectroscopy and data-driven molecular dynamics simulations, thus obtaining useful information for an efficient drug design.

Characterization and inhibition of beta-adrenergic receptor kinase in intact myocytes.

PubMed

Laugwitz, K L; Kronsbein, K; Schmitt, M; Hoffmann, K; Seyfarth, M; Schömig, A; Ungerer, M

1997-08-01

beta-Adrenergic receptor kinase (beta ARK) phosphorylates and thereby inactivates agonist-occupied beta-adrenergic receptors (beta AR). beta ARK is thought to play an important role in the regulation of cardiac function. Therefore, we studied beta ARK activation and its inhibition in intact smooth muscle cells and in cardiomyoblasts. beta AR agonist-stimulated translocation of beta ARK was monitored by immunofluorescence labelling with specific antibodies and confocal laser scanning microscopy in DDT-MF 2 hamster smooth muscle cells and in H9c2 rat cardiomyoblasts. In unstimulated cells. beta ARK was mainly located in the cytosol. After beta AR agonist stimulation, the beta ARK signal was partially translocated to the membranes. Liposomal gene transfer of the COOH-terminus of beta ARK ('beta ARKmini') as a beta ARK inhibitor led to functional expression of this protein in both cell lines with high efficiency. Western blots with beta ARK antibodies showed a gene concentration-dependent immunoreactivity of the 'beta ARKmini' protein. 'beta ARKmini'-transfected myocytes demonstrated reduced membrane targeting of the beta ARK immuno-fluorescence signal. Additionally, the effect of 'beta ARKmini' on beta AR-induced desensitization of myocytic cAMP accumulation was investigated. In control cells, desensitization with isoproterenol led to a subsequent reduction of beta AR-induced cAMP accumulation. In 'beta ARKmini'-transfected myocytes, this beta AR-induced desensitization was significantly diminished, whereas normal beta AR-induced cAMP accumulation was unaffected. A gene concentration of 2 micrograms 'beta ARKmini' DNA/100,000 cardiomyoblasts, and of 0.7 microgram 'beta ARKmini' DNA/100,000 DDT-MF2 smooth muscle cells led to approximately 5.9- and approximately 5.6-fold overexpressions of 'beta ARKmini' vs. native beta ARK, respectively. These gene doses proved sufficient to attenuate beta-adrenergic desensitization significantly. (1) beta ARK translocation was evidenced in DDT-MF2 smooth muscle cells and in cardiomyoblasts by confocal laser scanning microscopy. (2) Feasibility of 'beta ARKmini' gene transfer to myocytes was demonstrated, and necessary gene doses for beta ARK inhibition were titered. (3) Overexpression of 'beta ARKmini' functionally interacted with endogenous beta-adrenergic signal transduction, leading to sustained cAMP accumulation after prolonged beta-adrenergic stimulation.

Characterization of T cell repertoire changes in acute Kawasaki disease

PubMed Central

1993-01-01

Kawasaki disease (KD) is an acute multisystem vasculitis of unknown etiology that is associated with marked activation of T cells and monocyte/macrophages. Using a quantitative polymerase chain reaction (PCR) technique, we recently found that the acute phase of KD is associated with the expansion of T cells expressing the V beta 2 and V beta 8.1 gene segments. In the present work, we used a newly developed anti-V beta 2 monoclonal antibody (mAb) and studied a new group of KD patients to extend our previous PCR results. Immunofluorescence analysis confirmed that V beta 2-bearing T cells are selectively increased in patients with acute KD. The increase occurred primarily in the CD4 T cell subset. The percentages of V beta 2+ T cells as determined by mAb reactivity and flow cytometry correlated linearly with V beta expression as quantitated by PCR. However, T cells from acute KD patients appeared to express proportionately higher levels of V beta 2 transcripts per cell as compared with healthy controls or convalescent KD patients. Sequence analysis of T cell receptor beta chain genes of V beta 2 and V beta 8.1 expressing T cells from acute KD patients showed extensive junctional region diversity. These data showing polyclonal expansion of V beta 2+ and V beta 8+ T cells in acute KD provide additional insight into the immunopathogenesis of this disease. PMID:8094737

Overexpression of the VSSC-associated CAM, β-2, enhances LNCaP cell metastasis associated behavior.

PubMed

Jansson, Keith H; Lynch, Jill E; Lepori-Bui, Nadia; Czymmek, Kirk J; Duncan, Randall L; Sikes, Robert A

2012-07-01

Prostate cancer (PCa) is the second-leading cause of cancer death in American men. This is due largely to the "silent" nature of the disease until it has progressed to a highly metastatic and castrate resistant state. Voltage sensitive sodium channels (VSSCs) are multimeric transmembrane protein complexes comprised of a pore-forming α subunit and one or two β subunits. The β-subunits modulate surface expression and gating kinetics of the channels but also have inherent cell adhesion molecule (CAM) functions. We hypothesize that PCa cells use VSSC β-subunits as CAMs during PCa progression and metastasis. We overexpressed the beta-2 isoform as a C-terminal fusion protein with enhanced cyan fluorescence protein (ECFP) in the weakly metastatic LNCaP cells. The effect of beta-2 overexpression on cell morphology was examined using confocal microscopy while metastasis-associated behavior was tested by performing several in vitro metastatic functional assays and in vivo subcutaneous tumor studies. We found that cells overexpressing beta-2 (2BECFP) converted to a bipolar fibroblastic morphology. 2BECFP cells were more adhesive than control (ECFP) to vitronectin (twofold) and Matrigel® (1.3-fold), more invasive through Matrigel® (3.6-fold in 72 hr), and had enhanced migration (2.1-fold in 96 hr) independent of proliferation in wound-healing assays. In contrast, 2BECFP cells have a reduced tumor-take and tumor volume in vivo even though the overexpression of beta-2 was maintained. Functional overexpression of VSSC β-subunits in PCa may be one mechanism leading to increased metastatic behavior while decreasing the ability to form localized tumor masses. Copyright © 2011 Wiley Periodicals, Inc.

Heat shock protein-90 beta is expressed at the surface of multipotential mesenchymal precursor cells: generation of a novel monoclonal antibody, STRO-4, with specificity for mesenchymal precursor cells from human and ovine tissues.

PubMed

Gronthos, Stan; McCarty, Rosa; Mrozik, Krzysztof; Fitter, Stephen; Paton, Sharon; Menicanin, Danijela; Itescu, Silviu; Bartold, P Mark; Xian, Cory; Zannettino, Andrew C W

2009-11-01

Mesenchymal stromal cells (MSCs) and their precursor cells (MPCs) can proliferate and differentiate into multiple mesodermal and some ectodermal and endodermal tissues. Culture-expanded MSCs are currently being evaluated as a possible cell therapy to replace/repair injured or diseased tissues. While a number of mAb reagents with specificity to human MSCs, including STRO-1, STRO-3 (BLK ALP), CD71 (SH2, SH3), CD106 (VCAM-1), CD166, and CD271, have facilitated the isolation of purified populations of human MSCs from primary tissues, few if any mAb reagents have been described that can be used to isolate equivalent cells from other species. This is of particular relevance when assessing the tissue regenerative efficacy of MSCs in large immunocompetent, preclinical animal models of disease. In light of this, we sought to generate novel monoclonal antibodies (mAb) with specific reactivity against a cell surface molecule that is expressed at high levels by MSCs from different species. Using CD106 (VCAM-1)-selected ovine MSCs as an immunogen, mAb-producing hybridomas were selected for their reactivity to both human and ovine MSCs. One such hybridoma, termed STRO-4, produced an IgG mAb that reacted with <5% of human and ovine bone marrow (BM) mononuclear cells. As a single selection reagent, STRO-4 mAb was able to enrich colony-forming fibroblasts (CFU-F) in both human and ovine BM by 16- and 8-folds, respectively. Cells isolated with STRO-4 exhibited reactivity with markers commonly associated with MSCs isolated by plastic adherence including CD29, CD44, and CD166. Moreover, when placed in inductive culture conditions in vitro, STRO-4(+) MSCs exhibited multilineage differentiation potential and were capable of forming a mineralized matrix, lipid-filled adipocytes, and chondrocytes capable of forming a glycosaminoglycan-rich matrix. Biochemical analysis revealed that STRO-4 identified the beta isoform of heat shock protein-90 (Hsp90beta). In addition to identifying an antibody reagent that identifies a highly conserved epitope expressed by MSCs from different species, our study also points to a potential role for Hsp90beta in MSC biology.

[Exploration of relationship between the expression level of DNA polymerase beta and 60Co gamma-ray radiosensitivity].

PubMed

Cui, Jie; Xu, Xin; Yang, Mo; Chen, Chen; Zhao, Wei; Wu, Mei; Zhang, Zun-zhen

2011-11-01

To explore the relationship between the expression level of DNA polymerase beta (pol beta) and 60Co gamma-ray radiosensitivity and provide a basis on improving the efficiency of radiotherapy theoretically. pol beta wild-type cells (pol beta +/+), pol beta null cells (pol beta -/-) and pol beta overexpressed cells (polp beta oe) were applied as a model system. The radiosensitivity of 60Co gamma-ray on the cell was detected by MTT assay and clone formation assay. The DCFH-DA fluorescent probe was used to examine the cellular ROS after 60Co gamma-rays radiation. MTT assay showed that after radiation by 60Co gamma-rays followed with 72 h incubation, the cell viabilities in the three kinds of cells decreased significantly with a dose-response relationship (r-/+ = -0.976, r-/- = -0.977, r(oe) = -0.982, P<0.05). In addition, the viability of pol beta -/- cell was lower than those of other two kinds of cells at the same dose (P<0.05). Likewise, the colony number and colony formation rate in all tested cells also decreased after exposure to 60Co gamma-rays. The ROS level in the three kinds of cells was enhanced after treatment with 60Co gamma-ray, and the ROS level in pol beta -/- cells was much higher than that in the other two kinds of cells (P<0.05). Cell death caused by 60Co gamma-ray may associated with the DNA oxidative damage mediated by ROS; Overexpression of pol beta could protect against oxidative DNA damage, thus the cell apoptosis/death, thereby leading to reducing the radiosensitivity of 60Co gamma-rays, while null of DNA pol beta could increase radiosensitivity of 60Co gamma-rays by compromising the DNA repair.

Neuroglian-positive plasmatocytes of Manduca sexta and the initiation of hemocyte attachment to foreign surfaces.

PubMed

Nardi, James B; Pilas, Barbara; Bee, Charles Mark; Zhuang, Shufei; Garsha, Karl; Kanost, Michael R

2006-01-01

Observations of hemocyte aggregation on abiotic surfaces suggested that certain plasmatocytes from larvae of Manduca sexta act as foci for hemocyte aggregation. To establish how these particular plasmatocytes form initial attachments to foreign surfaces, they were cultured separately from other selected populations of hemocytes. While all circulating plasmatocytes immunolabel with anti-beta-integrin monoclonal antibody (MAb), only these larger plasmatocytes immunolabel with a MAb to the adhesion protein neuroglian. Neuroglian-negative plasmatocytes and granular cells that have been magnetically segregated from the majority of granular cells adhere to each other but fail to adhere to foreign substrata; by contrast, neuroglian-positive plasmatocytes that segregate with most granular cells adhere firmly to a substratum. Hemocytes form stable aggregates around the large, neuroglian-positive plasmatocytes. However, if neuroglian-positive plasmatocytes are separated from most granular cells, attachment of these plasmatocytes to foreign surfaces is suppressed.

Density-dependent induction of apoptosis by transforming growth factor-beta 1 in a human ovarian carcinoma cell line.

PubMed

Mathieu, C; Jozan, S; Mazars, P; Côme, M G; Moisand, A; Valette, A

1995-01-01

Transforming growth factor-beta 1 inhibited proliferation of a human ovarian carcinoma cell line (NIH-OVCAR-3). The inhibition of NIH-OVCAR-3 cell proliferation was accompanied by a decrease in clonogenic potential, evidenced by the reduced ability of TGF-beta 1-treated NIH-OVCAR-3 cells to form colonies on a plastic substratum. This rapid decrease of clonogenic potential, which was detected 6 h after addition of TGF-beta 1 was dose-dependent (IC50 = 4 pM). Fluorescence microscopy of DAPI-stained cells supported by electron-microscopic examination showed that TGF-beta 1 induced chromatin condensation and nuclear fragmentation. In addition, oligonucleosomal-sized fragments were detected in the TGF-beta 1-treated cells. These features indicated that TGF-beta 1 induced NIH-OVCAR-3 cell death by an apoptosis-like mechanism. This TGF-beta 1 apoptotic effect was subject to modulation by cell density. It was observed that an increase in cell density (up to 20 x 10(3) cells/cm2) protected NIH-OVCAR-3 cells against apoptosis induced by TGF-beta 1. Conditioned medium from high-density cultures of NIH-OVCAR-3 cells did not inhibit apoptosis induced by TGF-beta 1 on NIH-OVCAR-3 cells cultured at low density, suggesting that the protective effect of cell density was not related to the cell secretion of a soluble survival factor.

Evaluation of the transforming growth factor-beta activity in normal and dry eye human tears by CCL-185 cell bioassay.

PubMed

Zheng, Xiaofen; De Paiva, Cintia S; Rao, Kavita; Li, De-Quan; Farley, William J; Stern, Michael; Pflugfelder, Stephen C

2010-09-01

To develop a new bioassay method using human lung epithelial cells (CCL-185) to assess activity of transforming growth factor beta (TGF-beta) in human tear fluid from normal subjects and patients with dry eye. Two epithelial cell lines, mink lung cells (CCL-64) and human lung cells (CCL-185), were compared to detect the active form of TGF-beta by BrdU incorporation (quantitation of cell DNA synthesis) and WST assay (metabolic activity of viable cells). The effect of TGF-beta on the growth of CCL-185 cells was observed microscopically. Human tears from normal control subjects and patients with dry eye (DE) with and without Sjögren syndrome were evaluated for TGF-beta concentration by Luminex microbead assay, and TGF-beta activity by the CCL-185 cell growth inhibition bioassay. The metabolic activity of viable CCL-185 cells, measured by WST, was shown to be proportional to the TGF-beta1 concentration (R = 0.919) and confirmed by BrdU assay (R = 0.969). Compared with CCL-185, metabolic activity of viable cells and DNA synthesis, measured by WST and BrdU incorporation assays, were shown to be less proportional to the TGF-beta1 concentration in the CCL-64 line (R = 0.42 and 0.17, respectively). Coincubation with human anti-TGF-beta1 antibody (MAB-240) yielded a dose-dependent inhibition of TGF-beta1 (0.3 ng/mL) activity. CCL-185 cell growth observed microscopically was noted to decrease in response to increasing TGF-beta1 concentrations. Levels of immuodetectable TGF-beta1 and TGF-beta2 were similar in normal and DE tears. TGF-beta bioactivity in DE human tears measured by the CCL-185 cells assay was found to be higher (9777.5 +/- 10481.9 pg/mL) than those in normal controls (4129.3 +/- 1342.9 pg/mL) (P < 0.05). Among patients with DE, TGF-beta bioactivity was highest in those with Sjögren syndrome. Approximately, 79.1% of TGF-beta in DE tears and 37.6% TGF-beta in normal tears were found to be biologically active. The CCL-185 cell assay was found to be a suitable tool for assessing TGF-beta activity in human tears. Tear TGF-beta bioactivity increases in DE, particularly in Sjögren syndrome, where elevated levels of TGF-beta1 transcripts in the conjunctival epithelium have been previously detected.

Calreticulin is expressed on the cell surface of activated human peripheral blood T lymphocytes in association with major histocompatibility complex class I molecules.

PubMed

Arosa, F A; de Jesus, O; Porto, G; Carmo, A M; de Sousa, M

1999-06-11

Calreticulin is an endoplasmic reticulum resident molecule known to be involved in the folding and assembly of major histocompatibility complex (MHC) class I molecules. In the present study, expression of calreticulin was analyzed in human peripheral blood T lymphocytes. Pulse-chase experiments in [35S]methionine-labeled T cell blasts showed that calreticulin was associated with several proteins in the endoplasmic reticulum and suggested that it was expressed at the cell surface. Indeed, the 60-kDa calreticulin was labeled by cell surface biotinylation and precipitated from the surface of activated T cells together with a protein with an apparent molecular mass of 46 kDa. Cell surface expression of calreticulin by activated T lymphocytes was further confirmed by immunofluorescence and flow cytometry, studies that showed that both CD8+ and CD4+ T cells expressed calreticulin in the plasma membrane. Low amounts of cell surface calreticulin were detected in resting T lymphocytes. By sequential immunoprecipitation using the conformation independent monoclonal antibody HC-10, we provided evidence that the cell surface 46-kDa protein co-precipitated with calreticulin is unfolded MHC I. These results show for the first time that after T cell activation, significant amounts of calreticulin are expressed on the T cell surface, where they are found in physical association with a pool of beta2-free MHC class I molecules.

A Synopsis of Factors Regulating Beta Cell Development and Beta Cell Mass

PubMed Central

Prasadan, Krishna; Shiota, Chiyo; Xiangwei, Xiao; Ricks, David; Fusco, Joseph; Gittes, George

2016-01-01

The insulin-secreting beta cells in the endocrine pancreas regulate blood glucose levels, and loss of functional beta cells leads to insulin deficiency, hyperglycemia (high blood glucose) and diabetes mellitus. Current treatment strategies for type-1 (autoimmune) diabetes are islet transplantation, which has significant risks and limitations, or normalization of blood glucose with insulin injections, which is clearly not ideal. The type-1 patients can lack insulin counter-regulatory mechanism; therefore, hypoglycemia is a potential risk. Hence, a cell-based therapy offers a better alternative for the treatment of diabetes. Past research was focused on attempting to generate replacement beta cells from stem cells, however, recently there has been an increasing interest in identifying mechanisms that will lead to the conversion of pre-existing differentiated endocrine cells into beta cells. The goal of this review is to provide an overview of several of the key factors that regulate new beta cell formation (neogenesis) and beta cell proliferation. PMID:27105622

Studies on the bioavailability of the provitamin A carotenoid, beta-carotene, using human exfoliated colonic epithelial cells.

PubMed

Gireesh, T; Nair, P P; Sudhakaran, P R

2004-08-01

The possibility of using exfoliated colonic epithelial cells for assessing the bioavailability of beta-carotene was examined. Analysis of exfoliated colonic epithelial cells showed the presence of beta-carotene and vitamin A. The beta-carotene content was significantly lower in cells from stool samples of subjects on a beta-carotene-poor diet than those receiving a single dose of a beta-carotene supplement. Colonic epithelial cells isolated from stool samples collected daily during a wash-out period while the subjects were on a beta-carotene-poor diet showed a steady decrease in beta-carotene content, reaching the lowest value on day 7. Kinetic analysis showed that a single dose of a beta-carotene supplement in the form of spirulina (Spirulina platensis) or agathi (Sesbania grandiflora) after the wash-out period caused an increase in the beta-carotene content after a lag period of 5-7 d, but the vitamin A levels during these periods were not significantly affected. Analysis of plasma beta-carotene concentration also showed similar changes, which correlated with those of exfoliated colonic cells. A relationship between the beta-carotene content of the diet and that of the colonic epithelial cells suggests that analysis of the beta-carotene content in exfoliated human colonic epithelial cells is a useful non-invasive method to assess the bioavailability of provitamin A beta-carotene.

SIRT1 inhibits proliferation of pancreatic cancer cells expressing pancreatic adenocarcinoma up-regulated factor (PAUF), a novel oncogene, by suppression of {beta}-catenin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cho, Il-Rae; Koh, Sang Seok; Department of Functional Genomics, University of Science and Technology, Daejeon 305-333

2012-06-29

Highlights: Black-Right-Pointing-Pointer SIRT1 inhibits protein levels of {beta}-catenin and its transcriptional activity. Black-Right-Pointing-Pointer Nuclear localization of SIRT1 is not required for the decrease of {beta}-catenin expression. Black-Right-Pointing-Pointer SIRT1-mediated degradation of {beta}-catenin is not required for GSK-3{beta} and Siah-1 but for proteosome. Black-Right-Pointing-Pointer SIRT1 activation inhibits proliferation of pancreatic cancer cells expressing PAUF. -- Abstract: Because we found in a recent study that pancreatic adenocarcinoma up-regulated factor (PAUF), a novel oncogene, induces a rapid proliferation of pancreatic cells by up-regulation of {beta}-catenin, we postulated that {beta}-catenin might be a target molecule for pancreatic cancer treatment. We thus speculated whether SIRT1, knownmore » to target {beta}-catenin in a colon cancer model, suppresses {beta}-catenin in those pancreatic cancer cells that express PAUF (Panc-PAUF). We further evaluated whether such suppression would lead to inhibition of the proliferation of these cells. The ectopic expression of either SIRT1 or resveratrol (an activator of SIRT1) suppressed levels of {beta}-catenin protein and its transcriptional activity in Panc-PAUF cells. Conversely, suppression of SIRT1 expression by siRNA enhanced {beta}-catenin expression and transcriptional activity. SIRT1 mutant analysis showed that nuclear localization of SIRT1 is not required for reduction of {beta}-catenin. Treatment with MG132, a proteasomal inhibitor, restored {beta}-catenin protein levels, suggesting that SIRT1-mediated degradation of {beta}-catenin requires proteasomal activity. It was reported that inhibition of GSK-3{beta} or Siah-1 stabilizes {beta}-catenin in colon cancer cells, but suppression of GSK-3{beta} or Siah-1 using siRNA in the presence of resveratrol instead diminished {beta}-catenin protein levels in Panc-PAUF cells. This suggests that GSK-3{beta} and Siah-1 are not involved in SIRT1-mediated degradation of {beta}-catenin in the cells. Finally, activation of SIRT1 inhibited the proliferation of Panc-PAUF cells by down-regulation of cyclin-D1, a target molecule of {beta}-catenin. These results suggest that SIRT1 activation may be a therapeutic strategy for treatment of pancreatic cancer cells that express PAUF via the down-regulation of {beta}-catenin.« less

MST1 is a key regulator of beta cell apoptosis and dysfunction in diabetes.

PubMed

Ardestani, Amin; Paroni, Federico; Azizi, Zahra; Kaur, Supreet; Khobragade, Vrushali; Yuan, Ting; Frogne, Thomas; Tao, Wufan; Oberholzer, Jose; Pattou, Francois; Conte, Julie Kerr; Maedler, Kathrin

2014-04-01

Apoptotic cell death is a hallmark of the loss of insulin-producing beta cells in all forms of diabetes mellitus. Current treatments fail to halt the decline in functional beta cell mass, and strategies to prevent beta cell apoptosis and dysfunction are urgently needed. Here, we identified mammalian sterile 20-like kinase-1 (MST1) as a critical regulator of apoptotic beta cell death and function. Under diabetogenic conditions, MST1 was strongly activated in beta cells in human and mouse islets and specifically induced the mitochondrial-dependent pathway of apoptosis through upregulation of the BCL-2 homology-3 (BH3)-only protein BIM. MST1 directly phosphorylated the beta cell transcription factor PDX1 at T11, resulting in the latter's ubiquitination and degradation and thus in impaired insulin secretion. MST1 deficiency completely restored normoglycemia, beta cell function and survival in vitro and in vivo. We show MST1 as a proapoptotic kinase and key mediator of apoptotic signaling and beta cell dysfunction and suggest that it may serve as target for the development of new therapies for diabetes.

Both conditional ablation and overexpression of E2 SUMO-conjugating enzyme (UBC9) in mouse pancreatic beta cells result in impaired beta cell function.

PubMed

He, Xiaoyu; Lai, Qiaohong; Chen, Cai; Li, Na; Sun, Fei; Huang, Wenting; Zhang, Shu; Yu, Qilin; Yang, Ping; Xiong, Fei; Chen, Zhishui; Gong, Quan; Ren, Boxu; Weng, Jianping; Eizirik, Décio L; Zhou, Zhiguang; Wang, Cong-Yi

2018-04-01

Post-translational attachment of a small ubiquitin-like modifier (SUMO) to the lysine (K) residue(s) of target proteins (SUMOylation) is an evolutionary conserved regulatory mechanism. This modification has previously been demonstrated to be implicated in the control of a remarkably versatile regulatory mechanism of cellular processes. However, the exact regulatory role and biological actions of the E2 SUMO-conjugating enzyme (UBC9)-mediated SUMOylation function in pancreatic beta cells has remained elusive. Inducible beta cell-specific Ubc9 (also known as Ube2i) knockout (KO; Ubc9 Δbeta ) and transgenic (Ubc9 Tg ) mice were employed to address the impact of SUMOylation on beta cell viability and functionality. Ubc9 deficiency or overexpression was induced at 8 weeks of age using tamoxifen. To study the mechanism involved, we closely examined the regulation of the transcription factor nuclear factor erythroid 2-related factor 2 (NRF2) through SUMOylation in beta cells. Upon induction of Ubc9 deficiency, Ubc9 Δbeta islets exhibited a 3.5-fold higher accumulation of reactive oxygen species (ROS) than Ubc9 f/f control islets. Islets from Ubc9 Δbeta mice also had decreased insulin content and loss of beta cell mass after tamoxifen treatment. Specifically, at day 45 after Ubc9 deletion only 40% of beta cell mass remained in Ubc9 Δbeta mice, while 90% of beta cell mass was lost by day 75. Diabetes onset was noted in some Ubc9 Δbeta mice 8 weeks after induction of Ubc9 deficiency and all mice developed diabetes by 10 weeks following tamoxifen treatment. In contrast, Ubc9 Tg beta cells displayed an increased antioxidant ability but impaired insulin secretion. Unlike Ubc9 Δbeta mice, which spontaneously developed diabetes, Ubc9 Tg mice preserved normal non-fasting blood glucose levels without developing diabetes. It was noted that SUMOylation of NRF2 promoted its nuclear expression along with enhanced transcriptional activity, thereby preventing ROS accumulation in beta cells. SUMOylation function is required to protect against oxidative stress in beta cells; this mechanism is, at least in part, carried out by the regulation of NRF2 activity to enhance ROS detoxification. Homeostatic SUMOylation is also likely to be essential for maintaining beta cell functionality.

Transforming growth factor-beta inhibits human antigen-specific CD4+ T cell proliferation without modulating the cytokine response.

PubMed

Tiemessen, Machteld M; Kunzmann, Steffen; Schmidt-Weber, Carsten B; Garssen, Johan; Bruijnzeel-Koomen, Carla A F M; Knol, Edward F; van Hoffen, Els

2003-12-01

Transforming growth factor (TGF)-beta has been demonstrated to play a key role in the regulation of the immune response, mainly by its suppressive function towards cells of the immune system. In humans, the effect of TGF-beta on antigen-specific established memory T cells has not been investigated yet. In this study antigen-specific CD4(+) T cell clones (TCC) were used to determine the effect of TGF-beta on antigen-specific proliferation, the activation status of the T cells and their cytokine production. This study demonstrates that TGF-beta is an adequate suppressor of antigen-specific T cell proliferation, by reducing the cell-cycle rate rather than induction of apoptosis. Addition of TGF-beta resulted in increased CD69 expression and decreased CD25 expression on T cells, indicating that TGF-beta is able to modulate the activation status of in vivo differentiated T cells. On the contrary, the antigen-specific cytokine production was not affected by TGF-beta. Although TGF-beta was suppressive towards the majority of the T cells, insensitivity of a few TCC towards TGF-beta was also observed. This could not be correlated to differential expression of TGF-beta signaling molecules such as Smad3, Smad7, SARA (Smad anchor for receptor activation) and Hgs (hepatocyte growth factor-regulated tyrosine kinase substrate). In summary, TGF-beta has a pronounced inhibitory effect on antigen-specific T cell proliferation without modulating their cytokine production.

MicroRNA-29a is up-regulated in beta-cells by glucose and decreases glucose-stimulated insulin secretion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bagge, Annika; Clausen, Trine R.; Larsen, Sylvester

Highlights: Black-Right-Pointing-Pointer MicroRNA-29a (miR-29a) levels are increased by glucose in human and rat islets and INS-1E cells. Black-Right-Pointing-Pointer miR-29a increases proliferation of INS-1E beta-cells. Black-Right-Pointing-Pointer Forced expression of miR-29a decreases glucose-stimulated insulin secretion (GSIS). Black-Right-Pointing-Pointer Depletion of beta-cell miR-29a improves GSIS. Black-Right-Pointing-Pointer miR-29a may be a mediator of glucose toxicity in beta-cells. -- Abstract: Chronically elevated levels of glucose impair pancreatic beta-cell function while inducing beta-cell proliferation. MicroRNA-29a (miR-29a) levels are increased in several tissues in diabetic animals and mediate decreased insulin-stimulated glucose-transport of adipocytes. The aim was to investigate the impact of glucose on miR-29a levels in INS-1E beta-cellsmore » and in human islets of Langerhans and furthermore to evaluate the impact of miR-29a on beta-cell function and proliferation. Increased glucose levels up-regulated miR-29a in beta-cells and human and rat islets of Langerhans. Glucose-stimulated insulin-secretion (GSIS) of INS-1E beta-cells was decreased by forced expression of miR-29a, while depletion of endogenous miR-29a improved GSIS. Over-expression of miR-29a increased INS-1E proliferation. Thus, miR-29a up-regulation is involved in glucose-induced proliferation of beta-cells. Furthermore, as depletion of miR-29a improves beta-cell function, miR-29a is a mediator of glucose-induced beta-cell dysfunction. Glucose-induced up-regulation of miR-29a in beta-cells could be implicated in progression from impaired glucose tolerance to type 2 diabetes.« less

Origin and Properties of Prostatic Stem Cells

DTIC Science & Technology

2007-02-01

Brinster RL. beta1- and alpha6-integrin are surface markers on mouse spermatogonial stem cells. Proc Natl Acad Sci U S A 1999;96(10):5504-9. 14. Tsujimura ...G. R., Donjacour, A. A., Cooke, P. S., Mee, S., Bigsby, R. M., Higgins, S. J. & Sugimura, Y. (1987) Endocr. Rev. 8, 338–362. 9. Tsujimura , A...90. 4 Tsujimura A, Koikawa Y, Salm S et al. Proximal location of mouse prostate epithelial stem cells: A model of prostatic homeostasis. J Cell Biol

Follicle-stimulating hormone (FSH) activates extracellular signal-regulated kinase phosphorylation independently of beta-arrestin- and dynamin-mediated FSH receptor internalization

PubMed Central

Piketty, Vincent; Kara, Elodie; Guillou, Florian; Reiter, Eric; Crepieux, Pascale

2006-01-01

Background The follicle-stimulating hormone receptor (FSH-R) is a seven transmembrane spanning receptor (7TMR) which plays a crucial role in male and female reproduction. Upon FSH stimulation, the FSH-R activates the extracellular signal-regulated kinases (ERK). However, the mechanisms whereby the agonist-stimulated FSH-R activates ERK are poorly understood. In order to activate ERK, some 7 TMRs require beta-arrestin-and dynamin-dependent internalization to occur, whereas some others do not. In the present study, we examined the ability of the FSH-activated FSH-R to induce ERK phosphorylation, in conditions where its beta-arrestin- and dynamin-mediated internalization was impaired. Methods Human embryonic kidney (HEK) 293 cells were transiently transfected with the rat FSH-R. Internalization of the FSH-R was manipulated by co-expression of either a beta-arrestin (319–418) dominant negative peptide, either an inactive dynamin K44A mutant or of wild-type beta-arrestin 1 or 2. The outcomes on the FSH-R internalization were assayed by measuring 125I-FSH binding at the cell surface when compared to internalized 125I-FSH binding. The resulting ERK phosphorylation level was visualized by Western blot analysis. Results In HEK 293 cells, FSH stimulated ERK phosphorylation in a dose-dependent manner. Co-transfection of the beta- arrestin (319–418) construct, or of the dynamin K44A mutant reduced FSH-R internalization in response to FSH, without affecting ERK phosphorylation. Likewise, overexpression of wild-type beta-arrestin 1 or 2 significantly increased the FSH-R internalization level in response to FSH, without altering FSH-induced ERK phosphorylation. Conclusion From these results, we conclude that the FSH-R does not require beta-arrestin- nor dynamin-mediated internalization to initiate ERK phosphorylation in response to FSH. PMID:16787538

Elliptical-P cells in the avian perilymphatic interface of the Tegmentum vasculosum

NASA Technical Reports Server (NTRS)

Fermin, C. D.; Lee, D. H.; Martin, D. S.

1995-01-01

Elliptical cells (E-P) are present at the perilymphatic interface lumen (PIL) of the lagena. The E-P cells often separate from the tegmentum vasculosum (TV) and have touching processes that form a monolayer between the K+ rich perilymph and the Na+ rich endolymph, similar to the mammalian Reissner's membrane. We examined the TV of chicks (Gallus domesticus) and quantitated the expression of anti-S100 alphaalphabetabeta and S100 beta. There was a 30% increase of S100 beta saturation in the light cells facing the PIL when compared to other TV light cells. We show that: (1) the dimer anti- S100 alphaalphabetabeta and the monomer anti-S100 beta are expressed preferentially in the light cells and the E-P cells of TV; (2) expression of S100 beta is higher in light cells facing the PIL than in adjacent cells; (3) the expression of the dimer S100 alphaalphabetabeta and monomer S100 beta overlaps in most inner ear cell types, including the cells of the TV, most S100 alphaalphabetabeta positive cells express S 100 beta, but S100 beta positive cells do not always express S100 alphaalphabetabeta; and (4) the S100 beta expression in light cells, the abundant Na+-K+ ATPase on dark cells of the TV, and previously demonstrated co-localization of S100 beta/GABA in sensory cells suggest that S100 beta could have, in the inner ear, a dual neurotrophic-ionic modulating function.

Expression of S100 beta in sensory and secretory cells of the vertebrate inner ear

NASA Technical Reports Server (NTRS)

Fermin, C. D.; Martin, D. S.

1995-01-01

We evaluated anti-S100 beta expression in the chick (Gallus domesticus) inner ear and determined that: 1) the monomer anti-S100 beta is expressed differentially in the vestibular and auditory perikarya; 2) expression of S100 beta in the afferent nerve terminals is time-related to synapse and myelin formation; 3) the expression of the dimer anti-S100 alpha alpha beta beta and monomer anti-S100 beta overlaps in most inner ear cell types. Most S100 alpha alpha beta beta positive cells express S100 beta, but S100 beta positive cells do not always express S100 alpha alpha beta beta. 4) the expression of S100 beta is diffused over the perikaryal cytoplasm and nuclei of the acoustic ganglia but is concentrated over the nuclei of the vestibular perikarya. 6) S100 beta is expressed in secretory cells, and it is co-localized with GABA in sensory cells. 7) Color thresholding objective quantitation indicates that the amount of S100 beta was higher (mean 22, SD +/- 4) at E19 than at E9 (mean 34, SD +/- 3) in afferent axons. 8) Moreover, S100 beta was unchanged between E11-E19 in the perikaryal cytoplasm, but did change over the nuclei. At E9, 74%, and at E21, 5% of vestibular perikarya were positive. The data suggest that S100 beta may be physically associated with neuronal and ionic controlling cells of the vertebrate inner ear, where it could provide a dual ionic and neurotrophic modulatory function.

Adhesion to the extracellular matrix is positively regulated by retinoic acid in HepG2 cells.

PubMed

Massimi, Mara; Devirgiliis, Laura Conti

2007-02-01

In this work, we aimed to investigate the possible modulation of cell-matrix interactions by retinoic acid (RA), in view of the well-known role of the extracellular matrix (ECM) and integrins in hepatocyte differentiation and proliferation. For this purpose, we analysed the adhesion ability of HepG2 cells on different substrates in the presence and absence of RA evaluating both the expression and cellular localisation of major proteins involved in focal contacts, using Western blot and confocal microscopy. A positive and substrate-dependent effect of RA on cell-matrix adhesion was observed after long-term culture. The increased adhesiveness in the treated cells was accompanied by an enhanced expression of beta1 and alpha3 integrin subunits, together with a redistribution of beta1 receptors clustered at the basal surface. In contrast, the levels of focal adhesion kinase (FAK), paxillin and alpha-actinin were unchanged, as was the phosphorylation state of FAK. Nonetheless, a stronger association between beta1 integrin and intracytoplasmatic proteins of focal contacts was observed in coimmunoprecipitation experiments after RA treatment, suggesting improved connection with the actin cytoskeleton. These results are consistent with previously described antiproliferative and differentiative effects of RA on transformed hepatocytes, and confirm the hypothesis of a direct influence of RA on specific adhesion molecules.

Glycoconjugate sugar residues in the chick embryo developing lung: a lectin histochemical study.

PubMed

Gheri, G; Sgambati, E; Bryk, S G

2000-03-01

A lectin histochemical study was performed to investigate the distribution and changes of the oligosaccharidic component of the glycoconjugates in the lung of chick embryos, of 1-day-old chick, and of the adult animal. For this purpose, a battery of seven horseradish peroxidase-conjugated lectins (PNA, SBA, DBA, WGA, Con A, LTA, and UEA I) were employed. During the first phase of parabronchi and atria formation, D-galactose-(beta1-->3)-N-acetyl-D-galactosamine, beta-N-acetyl-D-galactosamine, D-glucosamine, alpha-D-mannose, and sialic acid, present at the level of the surface and of cytoplasmic granules of the lining epithelial cells, seem to play a role in regulating morphogenetic phenomena. In the subsequent phases, the parabronchial lumen and the atrial cavities were characterized by the presence of lectin-reactive material rich in terminal D-galactose-(beta1-->3)-N-acetyl-D-galactosamine, beta-N-acetyl-D-galactosamine, D-glucosamine and alpha-D-mannose. From day 18 onwards and immediately after hatching, the free border of the cells lining the air capillaries was characterized by the presence of beta-N-acetyl-D-galactosamine and alpha-D-mannose. The appearance of these sugar residues was concomitant with the beginning of respiratory activity. Copyright 2000 Wiley-Liss, Inc.

Expression and structural features of endoglin (CD105), a transforming growth factor beta1 and beta3 binding protein, in human melanoma.

PubMed Central

Altomonte, M.; Montagner, R.; Fonsatti, E.; Colizzi, F.; Cattarossi, I.; Brasoveanu, L. I.; Nicotra, M. R.; Cattelan, A.; Natali, P. G.; Maio, M.

1996-01-01

Human endoglin (CD105) is a member of the transforming growth factor beta (TGF-beta) receptor family that binds TGF-beta1 and -beta3, but not TGF-beta2, on human endothelial cells. Immunohistochemical analyses demonstrated that CD105 is expressed on normal and neoplastic cells of the melanocytic lineage. The anti-CD105 MAb, MAEND3, stained 50, 25 and 34% of intradermal naevi, primary and metastatic melanomas investigated, respectively, and nine out of 12 melanoma cell lines. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis revealed that CD105 expressed by melanoma cells consists of a homodimeric protein with an apparent molecular weight of 180 and 95 kDa under non-reducing and reducing conditions. Cross-linking of 125I-labelled TGF-beta1 to melanoma cells, Mel 97, by disuccinimidyl suberate (DSS) demonstrated that CD105 expressed on pigmented cells binds TGF-beta1; the pattern of binding of TGF-beta1 to melanoma cells was found to be similar to that of human umbilical vein endothelial cells. The addition of exogenous, bioactive TGF-beta1 significantly (P<0.05) inhibited the growth of CD105-positive melanoma cells, Mel 97, but did not affect that of CD105-negative melanoma cells, F0-1. These data, altogether, demonstrate that CD105 is expressed on pigmented cells and might play a functionally relevant role in the biology of human melanoma cells by regulating their sensitivity to TGF-betas. Images Figure 1 Figure 3 Figure 4 PMID:8932339

Demonstration of interleukin-1 beta transcripts in acute myeloblastic leukemic cells by in situ hybridization.

PubMed

Nakamura, M; Kanakura, Y; Furukawa, Y; Ernst, T J; Griffin, J D

1990-07-01

The cells from some patients with acute myeloblastic leukemia will secrete autostimulatory cytokines in tissue culture without the addition of stimulators such as phorbol 12-myristate 13-acetate. Production of interleukin-1 beta (IL-1 beta), for example, has been observed in up to 50% of cases. In order to investigate the nature of the cell secreting IL-1 beta in AML, we used an antisense RNA probe to detect specific IL-1 beta transcripts in individual leukemic cells by in situ hybridization. In fresh, uncultured cells, IL-1 beta transcripts were observed in 1-40% of undifferentiated leukemic blast cells in 17 of 19 cases. In situ hybridization was at least as sensitive as Northern blot analysis in detecting IL-1 beta transcripts. No correlation of IL-1 beta transcript expression with FAB classification was observed. Normal blood and bone marrow mononuclear cells did not contain cells expressing IL-1 beta transcripts. These results support the concept that the regulation of cytokine genes in AML cells is aberrant.

Isolation of major pancreatic cell types and long-term culture-initiating cells using novel human surface markers.

PubMed

Dorrell, Craig; Abraham, Stephanie L; Lanxon-Cookson, Kelsea M; Canaday, Pamela S; Streeter, Philip R; Grompe, Markus

2008-09-01

We have developed a novel panel of cell-surface markers for the isolation and study of all major cell types of the human pancreas. Hybridomas were selected after subtractive immunization of Balb/C mice with intact or dissociated human islets and assessed for cell-type specificity and cell-surface reactivity by immunohistochemistry and flow cytometry. Antibodies were identified by specific binding of surface antigens on islet (panendocrine or alpha-specific) and nonislet pancreatic cell subsets (exocrine and duct). These antibodies were used individually or in combination to isolate populations of alpha, beta, exocrine, or duct cells from primary human pancreas by FACS and to characterize the detailed cell composition of human islet preparations. They were also employed to show that human islet expansion cultures originated from nonendocrine cells and that insulin expression levels could be increased to up to 1% of normal islet cells by subpopulation sorting and overexpression of the transcription factors Pdx-1 and ngn3, an improvement over previous results with this culture system. These methods permit the analysis and isolation of functionally distinct pancreatic cell populations with potential for cell therapy.

Fc gamma RII/III and CD2 expression mark distinct subpopulations of immature CD4-CD8- murine thymocytes: in vivo developmental kinetics and T cell receptor beta chain rearrangement status.

PubMed

Rodewald, H R; Awad, K; Moingeon, P; D'Adamio, L; Rabinowitz, D; Shinkai, Y; Alt, F W; Reinherz, E L

1993-04-01

We have recently identified a dominant wave of CD4-CD8- (double-negative [DN]) thymocytes in early murine fetal development that express low affinity Fc gamma receptors (Fc gamma RII/III) and contain precursors for Ti alpha/beta lineage T cells. Here we show that Fc gamma RII/III is expressed in very immature CD4low single-positive (SP) thymocytes and that Fc gamma RII/III expression is downregulated within the DN subpopulation and before the CD3-CD8low SP stage in T cell receptor (TCR)-alpha/beta lineage-committed thymocytes. DN Fc gamma RII/III+ thymocytes also contain a small fraction of TCR-gamma/delta lineage cells in addition to TCR-alpha/beta progenitors. Fetal day 15.5 DN TCR-alpha/beta lineage progenitors can be subdivided into three major subpopulations as characterized by cell surface expression of Fc gamma RII/III vs. CD2 (Fc gamma RII/III+CD2-, Fc gamma RII/III+CD2+, Fc gamma RII/III-CD2+). Phenotypic analysis during fetal development as well as adoptive transfer of isolated fetal thymocyte subpopulations derived from C57B1/6 (Ly5.1) mice into normal, nonirradiated Ly5.2 congenic recipient mice identifies one early differentiation sequence (Fc gamma RII/III+CD2(-)-->Fc gamma RII/III+CD2(+)-->Fc gamma RII/III-CD2+) that precedes the entry of DN thymocytes into the CD4+CD8+ double-positive (DP) TCRlow/- stage. Unseparated day 15.5 fetal thymocytes develop into DP thymocytes within 2.5 d and remain at the DP stage for > 48 h before being selected into either CD4+ or CD8+ SP thymocytes. In contrast, Fc gamma RII/III+CD2- DN thymocytes follow this same developmental pathway but are delayed by approximately 24 h before entering the DP compartment, while Fc gamma RII/III-CD2+ display accelerated development by approximately 24 h compared with total day 15.5 thymocytes. Fc gamma RII/III-CD2+ are also more developmentally advanced than Fc gamma RII/III+CD2- fetal thymocytes with respect to their TCR beta chain V(D)J rearrangement. At day 15.5 in gestation, beta chain V(D)J rearrangement is mostly, if not entirely, restricted to the Fc gamma RII/III-CD2+ subset of DN fetal thymocytes. Consistent with this analysis in fetal thymocytes, > 90% of adult thymocytes derived from mice carrying a disrupting mutation at the recombination-activating gene 2 locus (RAG-2-/-) on both alleles are developmentally arrested at the DN CD2- stage. In addition, there is a fivefold increase in the relative percentage of thymocytes expressing Fc gamma RII/III in TCR and immunoglobulin gene rearrangement-incompetent homozygous RAG-2-/- mice (15% Fc gamma RII/III+) versus rearrangement-competent heterozygous RAG-2+/- mice (< 3% Fc gamma RII/III+). Thus, Fc gamma RII/III expression defines an early DN stage preceding V beta(D beta)I beta rearrangement, which in turn is followed by surface expression of CD2. Loss of Fc gamma RII/III and acquisition of CD2 expression characterize a late DN stage immediately before the conversion into DP thymocytes.

Id-1 promotes TGF-{beta}1-induced cell motility through HSP27 activation and disassembly of adherens junction in prostate epithelial cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Di Kaijun; Wong, Y.C.; Wang Xianghong

Id-1 (inhibitor of differentiation or DNA binding-1) has been positively associated with cell proliferation, cell cycle progression, and invasiveness during tumorigenesis. In addition, Id-1 has been shown to modulate cellular sensitivity to TGF-{beta}1 (transforming growth factor {beta}1). Here we demonstrate a novel role of Id-1 in promoting TGF-{beta}1-induced cell motility in a non-malignant prostate epithelial cell line, NPTX. We found that Id-1 promoted F-actin stress fiber formation in response to TGF-{beta}1, which was associated with increased cell-substrate adhesion and cell migration in NPTX cells. In addition, this positive effect of Id-1 on TGF-{beta}1-induced cell motility was mediated through activation ofmore » MEK-ERK signaling pathway and subsequent phosphorylation of HSP27 (heat shock protein 27). Furthermore, Id-1 disrupted the adherens junction complex in TGF-{beta}1-treated cells through down-regulation of E-cadherin, redistribution of {beta}-catenin, along with up-regulation of N-cadherin. These lines of evidence reveal a novel tumorigenic role of Id-1 through reorganization of actin cytoskeleton and disassembly of cell-cell adhesion in response to TGF-{beta}1 in human prostate epithelial cells, and suggest that intracellular Id-1 levels might be a determining factor for switching TGF-{beta}1 from a growth inhibitor to a tumor promoter during prostate carcinogenesis.« less

Cell surface control of the multiubiquitination and deubiquitination of high-affinity immunoglobulin E receptors.

PubMed Central

Paolini, R; Kinet, J P

1993-01-01

Multiubiquitination of proteins is a critical step leading to selective degradation for many polypeptides. Therefore, activation-induced multiubiquitination of cell surface receptors, such as the platelet-derived growth factor (PDGF) receptor and the T cell antigen (TCR) receptor, may correspond to a degradation pathway for ligand-receptor complexes. Here we show that the antigen-induced engagement of high-affinity immunoglobulin E receptors (Fc epsilon RI) results in the immediate multiubiquitination of Fc epsilon RI beta and gamma chains. This ubiquitination is independent of receptor phosphorylation and is restricted to activated receptors. Surprisingly, receptor multiubiquitination is immediately reversible when receptors are disengaged. Therefore, multiubiquitination and deubiquitination of Fc epsilon RI receptors is controlled at the cell surface by receptor engagement and disengagement. The rapidity, specificity and, most importantly, the reversibility of the activation-induced receptor multiubiquitination suggest that this process may turn on/off a cell surface receptor signaling function thus far unsuspected. Images PMID:8382611

Preimplantation embryo development in vitro: cooperative interactions among embryos and role of growth factors.

PubMed Central

Paria, B C; Dey, S K

1990-01-01

We have established a model that shows cooperative interaction among preimplantation embryos and the role of growth factors on their development and growth. Two-cell mouse embryos cultured singly in 25-microliters microdrops had inferior development to blastocysts and lower cell numbers per blastocyst compared with those cultured in groups of 5 or 10. The inferior development of singly cultured embryos was markedly improved by addition of epidermal growth factor (EGF) or transforming growth factor alpha or beta 1 (TGF-alpha or TGF-beta 1) to the culture medium. The stage of embryonic development, primarily affected by these treatments, was between eight-cell/morula and blastocyst. Furthermore, blastocysts developed from eight-cell embryos cultured in groups or singly in the presence of EGF showed a higher incidence of zona hatching compared with those cultured singly in the absence of EGF. Detection of EGF receptors on the embryonic cell surface at eight-cell/morula and blastocyst stages suggests beneficial effects of EGF or TGF-alpha on preimplantation embryo development and blastocyst functions. Insulin-like growth factor I (IGF-I) had no influence on embryo development. To further document the cooperative interactions among embryos, the volume of the culture medium was doubled to 50 microliters. This increase in culture volume was even more detrimental to the development of singly cultured embryos. However, this detrimental effect was significantly reversed by EGF and reversed even more markedly by a combination of EGF and TGF-beta 1 but not by TGF-beta 1 alone. Although TGF-beta 1 plus IGF-I caused a modest improvement of embryo development, the response was not as great as shown by EGF alone. Furthermore, IGF-I had no additive effect on EGF-induced embryonic development. The study presents clear evidence that specific growth factors of embryonic and/or reproductive tract origin participate in preimplantation embryo development and blastocyst functions in an autocrine/paracrine manner. Images PMID:2352946

Absence of Fc epsilonRI alpha chain results in upregulation of Fc gammaRIII-dependent mast cell degranulation and anaphylaxis. Evidence of competition between Fc epsilonRI and Fc gammaRIII for limiting amounts of FcR beta and gamma chains.

PubMed Central

Dombrowicz, D; Flamand, V; Miyajima, I; Ravetch, J V; Galli, S J; Kinet, J P

1997-01-01

In mouse mast cells, both Fc epsilonRI and Fc gammaRIII are alpha beta gamma2 tetrameric complexes in which different alpha chains confer IgE or IgG ligand recognition while the signaling FcR beta and gamma chains are identical. We used primarily noninvasive techniques (changes in body temperature, dye extravasation) to assess systemic anaphylactic responses in nonanesthetized wild-type, Fc epsilonRI alpha chain -/- and FcR gamma chain -/- mice. We confirm that systemic anaphylaxis in mice can be mediated largely through IgG1 and Fc gammaRIII and we provide direct evidence that these responses reflect activation of Fc gammaRIII rather than Fc gammaRI. Furthermore, we show that Fc gammaRIII-dependent responses are more intense in normal than in congenic mast cell-deficient KitW/KitW-v mice, indicating that Fc gammaRIII responses have mast cell-dependent and -independent components. Finally, we demonstrate that the upregulation of cell surface expression of Fc gammaRIII seen in Fc epsilonRI alpha chain -/- mice corresponds to an increased association of Fc gammaRIII alpha chains with FcR beta and gamma chains and is associated with enhanced Fc gammaRIII-dependent mast cell degranulation and systemic anaphylactic responses. Therefore, the phenotype of the Fc epsilonRI alpha chain -/- mice suggests that expression of Fc epsilonRI and Fc gammaRIII is limited by availability of the FcR beta and gamma chains and that, in normal mice, changes in the expression of one receptor (Fc epsilonRI) may influence the expression of functional responses dependent on the other (Fc gammaRIII). PMID:9062349

Antidiabetic and Beta Cell-Protection Activities of Purple Corn Anthocyanins

PubMed Central

Hong, Su Hee; Heo, Jee-In; Kim, Jeong-Hyeon; Kwon, Sang-Oh; Yeo, Kyung-Mok; Bakowska-Barczak, Anna M.; Kolodziejczyk, Paul; Ryu, Ok-Hyun; Choi, Moon-Ki; Kang, Young-Hee; Lim, Soon Sung; Suh, Hong-Won; Huh, Sung-Oh; Lee, Jae-Yong

2013-01-01

Antidiabetic and beta cell-protection activities of purple corn anthocyanins (PCA) were examined in pancreatic beta cell culture and db/db mice. Only PCA among several plant anthocyanins and polyphenols showed insulin secretion activity in culture of HIT-T15 cells. PCA had excellent antihyperglycemic activity (in terms of blood glucose level and OGTT) and HbA1c-decreasing activity when compared with glimepiride, a sulfonylurea in db/db mice. In addition, PCA showed efficient protection activity of pancreatic beta cell from cell death in HIT-T15 cell culture and db/db mice. The result showed that PCA had antidiabetic and beta cell-protection activities in pancreatic beta cell culture and db/db mice. PMID:24244813

Age-related islet inflammation marks the proliferative decline of pancreatic beta-cells in zebrafish

PubMed Central

Tsakmaki, Anastasia; Mousavy Gharavy, S Neda; Murawala, Priyanka; Konantz, Judith; Birke, Sarah; Hodson, David J; Rutter, Guy A; Bewick, Gavin A

2018-01-01

The pancreatic islet, a cellular community harboring the insulin-producing beta-cells, is known to undergo age-related alterations. However, only a handful of signals associated with aging have been identified. By comparing beta-cells from younger and older zebrafish, here we show that the aging islets exhibit signs of chronic inflammation. These include recruitment of tnfα-expressing macrophages and the activation of NF-kB signaling in beta-cells. Using a transgenic reporter, we show that NF-kB activity is undetectable in juvenile beta-cells, whereas cells from older fish exhibit heterogeneous NF-kB activity. We link this heterogeneity to differences in gene expression and proliferation. Beta-cells with high NF-kB signaling proliferate significantly less compared to their neighbors with low activity. The NF-kB signalinghi cells also exhibit premature upregulation of socs2, an age-related gene that inhibits beta-cell proliferation. Together, our results show that NF-kB activity marks the asynchronous decline in beta-cell proliferation with advancing age. PMID:29624168

Transforming growth factor-{beta}-inducible phosphorylation of Smad3.

PubMed

Wang, Guannan; Matsuura, Isao; He, Dongming; Liu, Fang

2009-04-10

Smad proteins transduce the transforming growth factor-beta (TGF-beta) signal at the cell surface into gene regulation in the nucleus. Upon TGF-beta treatment, the highly homologous Smad2 and Smad3 are phosphorylated by the TGF-beta receptor at the SSXS motif in the C-terminal tail. Here we show that in addition to the C-tail, three (S/T)-P sites in the Smad3 linker region, Ser(208), Ser(204), and Thr(179) are phosphorylated in response to TGF-beta. The linker phosphorylation peaks at 1 h after TGF-beta treatment, behind the peak of the C-tail phosphorylation. We provide evidence suggesting that the C-tail phosphorylation by the TGF-beta receptor is necessary for the TGF-beta-induced linker phosphorylation. Although the TGF-beta receptor is necessary for the linker phosphorylation, the receptor itself does not phosphorylate these sites. We further show that ERK is not responsible for TGF-beta-dependent phosphorylation of these three sites. We show that GSK3 accounts for TGF-beta-inducible Ser(204) phosphorylation. Flavopiridol, a pan-CDK inhibitor, abolishes TGF-beta-induced phosphorylation of Thr(179) and Ser(208), suggesting that the CDK family is responsible for phosphorylation of Thr(179) and Ser(208) in response to TGF-beta. Mutation of the linker phosphorylation sites to nonphosphorylatable residues increases the ability of Smad3 to activate a TGF-beta/Smad-target gene as well as the growth-inhibitory function of Smad3. Thus, these observations suggest that TGF-beta-induced phosphorylation of Smad3 linker sites inhibits its antiproliferative activity.

Reduced Expression of the Liver/Beta-Cell Glucose Transporter Isoform in Glucose-Insensitive Pancreatic Beta Cells of Diabetic Rats

NASA Astrophysics Data System (ADS)

Thorens, Bernard; Weir, Gordon C.; Leahy, John L.; Lodish, Harvey F.; Bonner-Weir, Susan

1990-09-01

Rats injected with a single dose of streptozocin at 2 days of age develop non-insulin-dependent diabetes 6 weeks later. The pancreatic beta islet cells of these diabetic rats display a loss of glucose-induced insulin secretion while maintaining sensitivity to other secretagogues such as arginine. We analyzed the level of expression of the liver/beta-cell glucose transporter isoform in diabetic islets by immunofluorescence staining of pancreas sections and by Western blotting of islet lysates. Islets from diabetic animals have a reduced expression of this beta-cell-specific glucose transporter isoform and the extent of reduction is correlated with the severity of hyperglycemia. In contrast, expression of this transporter isoform in liver is minimally modified by the diabetes. Thus a decreased expression of the liver/beta-cell glucose transporter isoform in beta cells is associated with the impaired glucose sensing characteristic of diabetic islets; our data suggest that this glucose transporter may be part of the beta-cell glucose sensor.

The role of peroxisome proliferator-activated receptor-{beta}/{delta} in epidermal growth factor-induced HaCaT cell proliferation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liang Pengfei; Jiang Bimei; Yang Xinghua

2008-10-15

Epidermal growth factor (EGF) has been shown to be a potent mitogen for epidermal cells both in vitro and in vivo, thus contributing to the development of an organism. It has recently become clear that peroxisome proliferator-activated receptor-{beta}/{delta} (PPAR{beta}/{delta}) expression and activation is involved in the cell proliferation. However, little is known about the role of PPAR{beta}/{delta} in EGF-induced proliferation of HaCaT keratinocytes. In this study, HaCaT cells were cultured in the presence and absence of EGF and we identified that EGF induced an increase of PPAR{beta}/{delta} mRNA and protein level expression in time-dependent and dose-dependent manner, and AG1487, anmore » EGF receptor (EGFR) special inhibitor, caused attenuation of PPAR{beta}/{delta} protein expression. Electrophoretic mobility shift assay (EMSA) revealed that EGF significantly increased PPAR{beta}/{delta} binding activity in HaCaT keratinocytes. Antisense phosphorothioate oligonucleotides (asODNs) against PPAR{beta}/{delta} caused selectively inhibition of PPAR{beta}/{delta} protein content induced by EGF and significantly attenuated EGF-mediated cell proliferation. Treatment of the cells with L165041, a specific synthetic ligand for PPAR{beta}/{delta}, significantly enhanced EGF-mediated cell proliferation. Finally, c-Jun ablation inhibited PPAR{beta}/{delta} up-regulation induced by EGF, and chromatin immunoprecipitation (ChIP) showed that c-Jun bound to the PPAR{beta}/{delta} promoter and the binding increased in EGF-stimulated cells. These results demonstrate that EGF induces PPAR{beta}/{delta} expression in a c-Jun-dependent manner and PPAR{beta}/{delta} plays a vital role in EGF-stimulated proliferation of HaCaT cells.« less

Solution structure and interactions of the Escherichia coli cell division activator protein CedA.

PubMed

Chen, Ho An; Simpson, Peter; Huyton, Trevor; Roper, David; Matthews, Stephen

2005-05-10

CedA is a protein that is postulated to be involved in the regulation of cell division in Escherichia coli and related organisms; however, little biological data about its possible mode of action are available. Here we present a three-dimensional structure of this protein as determined by NMR spectroscopy. The protein is made up of four antiparallel beta-strands, an alpha-helix, and a large unstructured stretch of residues at the N-terminus. It shows structural similarity to a family of DNA-binding proteins which interact with dsDNA via a three-stranded beta-sheet, suggesting that CedA may be a DNA-binding protein. The putative binding surface of CedA is predominantly positively charged with a number of basic residues surrounding a groove largely dominated by aromatic residues. NMR chemical shift perturbations and gel-shift experiments performed with CedA confirm that the protein binds dsDNA, and its interaction is mediated primarily via the beta-sheet.

Relationships of pancreatic beta-cell function with microalbuminuria and glomerular filtration rate in middle-aged and elderly population without type 2 diabetes mellitus: a Chinese community-based analysis.

PubMed

Fu, Shihui; Zhou, Shanjing; Luo, Leiming; Ye, Ping

2017-01-01

Relationships of pancreatic beta-cell function abnormality with microalbuminuria (MA) and glomerular filtration rate (GFR) may differ by age, ethnicity and accompanied diseases. Previous studies were generally conducted in Western adult patients with type 2 diabetes mellitus (T2DM), and it is uncertain whether pancreatic beta-cell function is associated with MA and GFR in Chinese community-dwelling middle-aged and elderly population without T2DM. We therefore examined the relationships of pancreatic beta-cell function with two indices of renal damage, MA and GFR, in Chinese community-dwelling middle-aged and elderly population without T2DM. This analysis focused on 380 Beijing residents older than 45 years who were free of T2DM and completed the evaluation of pancreatic beta-cell function. Median age was 67 (49-80) years. Levels of triglyceride, diastolic blood pressure and homeostasis model assessment-beta (HOMA-beta) index were positively related to urine microalbumin ( P <0.05 for all). Age, low-density lipoprotein cholesterol levels and HOMA-beta index were inversely correlated with GFR, while high-density lipoprotein cholesterol levels were positively correlated with GFR ( P <0.05 for all). In all three adjustment models, there was a significant positive association between HOMA-beta index and MA; subjects with higher beta-cell function had higher odds of MA ( P <0.05 for all). There was no association between HOMA-beta index and GFR <60 mL/min/1.73 m 2 in any model ( P >0.05 for all). Modeling the pancreatic beta-cell function with different adjusted variables provided the same conclusion of association with MA; beta-cell function was positively associated with MA. Additionally, there was a specific difference in the adjusted associations of pancreatic beta-cell function with MA and GFR <60 mL/min/1.73 m 2 ; beta-cell function was not independently associated with GFR <60 mL/min/1.73 m 2 . This result indicated that abnormal pancreatic beta-cell function plays an important role in the development of MA.

Transforming growth factor-beta1 promotes the migration and invasion of sphere-forming stem-like cell subpopulations in esophageal cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yue, Dongli; Zhang, Zhen; Li, Jieyao

Esophageal cancer is one of the most lethal solid malignancies. Mounting evidence demonstrates that cancer stem cells (CSCs) are able to cause tumor initiation, metastasis and responsible for chemotherapy and radiotherapy failures. As CSCs are thought to be the main reason of therapeutic failure, these cells must be effectively targeted to elicit long-lasting therapeutic responses. We aimed to enrich and identify the esophageal cancer cell subpopulation with stem-like properties and help to develop new target therapy strategies for CSCs. Here, we found esophageal cancer cells KYSE70 and TE1 could form spheres in ultra low attachment surface culture and be seriallymore » passaged. Sphere-forming cells could redifferentiate and acquire morphology comparable to parental cells, when return to adherent culture. The sphere-forming cells possessed the key criteria that define CSCs: persistent self-renewal, overexpression of stemness genes (SOX2, ALDH1A1 and KLF4), reduced expression of differentiation marker CK4, chemoresistance, strong invasion and enhanced tumorigenic potential. SB525334, transforming growth factor-beta 1(TGF-β1) inhibitor, significantly inhibited migration and invasion of sphere-forming stem-like cells and had no effect on sphere-forming ability. In conclusion, esophageal cancer sphere-forming cells from KYSE70 and TE1 cultured in ultra low attachment surface possess cancer stem cell properties, providing a model for CSCs targeted therapy. TGF-β1 promotes the migration and invasion of sphere-forming stem-like cells, which may guide future studies on therapeutic strategies targeting these cells. - Highlights: • Esophageal cancer sphere-forming cells possess cancer stem cell properties. • Sphere-forming cells enhance TGF-β1 pathway activity. • TGF-β 1 inhibitor suppresses the migration and invasion of sphere-forming cells.« less

TGF{beta} induces proHB-EGF shedding and EGFR transactivation through ADAM activation in gastric cancer cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ebi, Masahide; Kataoka, Hiromi, E-mail: hkataoka@med.nagoya-cu.ac.jp; Shimura, Takaya

2010-11-19

Research highlights: {yields} TGF{beta} induces EGFR transactivation through proHB-EGF shedding by activated ADAM members in gastric cancer cells. {yields} TGF{beta} induces nuclear translocation of HB-EGF-CTF cleaved by ADAM members. {yields} TGF{beta} enhances cell growth by EGFR transactivation and HB-EGF-CTF nuclear translocation and ADAM inhibitors block these effects. {yields} Silencing of ADAM17 also blocks EGFR transactivation, HB-EGF-CTF nuclear translocation and cancer cell growth by TGF{beta}. {yields} ADAM17 may play a crucial role in this TGF{beta}-HB-EGF signal transduction. -- Abstract: Background and aims: Transforming growth factor-beta (TGF{beta}) is known to potently inhibit cell growth. Loss of responsiveness to TGF{beta} inhibition on cellmore » growth is a hallmark of many types of cancer, yet its mechanism is not fully understood. Membrane-anchored heparin-binding EGF-like growth factor (proHB-EGF) ectodomain is cleaved by a disintegrin and metalloproteinase (ADAM) members and is implicated in epidermal growth factor receptor (EGFR) transactivation. Recently, nuclear translocation of the C-terminal fragment (CTF) of pro-HB-EGF was found to induce cell growth. We investigated the association between TGF{beta} and HB-EGF signal transduction via ADAM activation. Materials and methods: The CCK-8 assay in two gastric cancer cell lines was used to determine the effect for cell growth by TGF{beta}. The effect of two ADAM inhibitors was also evaluated. Induction of EGFR phosphorylation by TGF{beta} was analyzed and the effect of the ADAM inhibitors was also examined. Nuclear translocation of HB-EGF-CTF by shedding through ADAM activated by TGF{beta} was also analyzed. EGFR transactivation, HB-EGF-CTF nuclear translocation, and cell growth were examined under the condition of ADAM17 knockdown. Result: TGF{beta}-induced EGFR phosphorylation of which ADAM inhibitors were able to inhibit. TGF{beta} induced shedding of proHB-EGF allowing HB-EGF-CTF to translocate to the nucleus. ADAM inhibitors blocked this nuclear translocation. TGF{beta} enhanced gastric cancer cell growth and ADAM inhibitors suppressed this effect. EGFR phosphorylation, HB-EGF-CTF nuclear translocation, and cell growth were suppressed in ADAM17 knockdown cells. Conclusion: HB-EGF-CTF nuclear translocation and EGFR transactivation from proHB-EGF shedding mediated by ADAM17 activated by TGF{beta} might be an important pathway of gastric cancer cell proliferation by TGF{beta}.« less

Neurotensin protects pancreatic beta cells from apoptosis.

PubMed

Coppola, Thierry; Béraud-Dufour, Sophie; Antoine, Aurélie; Vincent, Jean-Pierre; Mazella, Jean

2008-01-01

The survival of pancreatic beta cells depends on the balance between external cytotoxic and protective molecular systems. The neuropeptide neurotensin (NT) has been shown to regulate certain functions of the endocrine pancreas including insulin and glucagon release. However, the mechanism of action of NT as well as the identification of receptors involved in the pancreatic functions of the peptide remained to be studied. We demonstrate here that NT is an efficient protective agent of pancreatic beta cells against cytotoxic agents. Both beta-TC3 and INS-1E cell lines and the mouse pancreatic islet cells express the three known NT receptors. The incubation of beta cells with NT protects cells from apoptosis induced either by staurosporine or by IL-1beta. In beta-TC3 cells, NT activates both MAP and PI-3 kinases pathways and strongly reduces the staurosporine or the Il-1beta-induced caspase-3 activity by a mechanism involving Akt activation. The NTSR2 agonist levocabastine displays the same protective effect than NT whereas the NTSR1 antagonist is unable to block the effect of NT suggesting the predominant involvement of the NTSR2 in the action of NT on beta cells. These results clearly indicate for the first time that NT is able to protect endocrine beta cells from external cytotoxic agents, a role well correlated with its release in the circulation after a meal.

Comparison of Continuous Wave CO2 Doppler Lidar Calibration Using Earth Surface Targets in Laboratory and Airborne Measurements

NASA Technical Reports Server (NTRS)

Jarzembski, Maurice A.; Srivastava, Vandana

1999-01-01

Routine backscatter, beta, measurements by an airborne or space-based lidar from designated earth surfaces with known and fairly uniform beta properties can potentially offer lidar calibration opportunities. This can in turn be used to obtain accurate atmospheric aerosol and cloud beta measurements on large spatial scales. This is important because achieving a precise calibration factor for large pulsed lidars then need not rest solely on using a standard hard target procedure. Furthermore, calibration from designated earth surfaces would provide an inflight performance evaluation of the lidar. Hence, with active remote sensing using lasers with high resolution data, calibration of a space-based lidar using earth's surfaces will be extremely useful. The calibration methodology using the earth's surface initially requires measuring beta of various earth surfaces simulated in the laboratory using a focused continuous wave (CW) CO2 Doppler lidar and then use these beta measurements as standards for the earth surface signal from airborne or space-based lidars. Since beta from the earth's surface may be retrieved at different angles of incidence, beta would also need to be measured at various angles of incidences of the different surfaces. In general, Earth-surface reflectance measurements have been made in the infrared, but the use of lidars to characterize them and in turn use of the Earth's surface to calibrate lidars has not been made. The feasibility of this calibration methodology is demonstrated through a comparison of these laboratory measurements with actual earth surface beta retrieved from the same lidar during the NASA/Multi-center Airborne Coherent Atmospheric Wind Sensor (MACAWS) mission on NASA's DC8 aircraft from 13 - 26 September, 1995. For the selected earth surface from the airborne lidar data, an average beta for the surface was established and the statistics of lidar efficiency was determined. This was compared with the actual lidar efficiency determined with the standard calibrating hard target.

Pancreatic islets and insulinoma cells express a novel isoform of group VIA phospholipase A2 (iPLA2 beta) that participates in glucose-stimulated insulin secretion and is not produced by alternate splicing of the iPLA2 beta transcript.

PubMed

Ramanadham, Sasanka; Song, Haowei; Hsu, Fong-Fu; Zhang, Sheng; Crankshaw, Mark; Grant, Gregory A; Newgard, Christopher B; Bao, Shunzhong; Ma, Zhongmin; Turk, John

2003-12-02

Many cells express a group VIA 84 kDa phospholipase A(2) (iPLA(2)beta) that is sensitive to inhibition by a bromoenol lactone (BEL) suicide substrate. Inhibition of iPLA(2)beta in pancreatic islets and insulinoma cells suppresses, and overexpression of iPLA(2)beta in INS-1 insulinoma cells amplifies, glucose-stimulated insulin secretion, suggesting that iPLA(2)beta participates in secretion. Western blotting analyses reveal that glucose-responsive 832/13 INS-1 cells express essentially no 84 kDa iPLA(2)beta-immunoreactive protein but predominantly express a previously unrecognized immunoreactive iPLA(2)beta protein in the 70 kDa region that is not generated by a mechanism of alternate splicing of the iPLA(2)beta transcript. To determine if the 70 kDa-immunoreactive protein is a short isoform of iPLA(2)beta, protein from the 70 kDa region was digested with trypsin and analyzed by mass spectrometry. Such analyses reveal several peptides with masses and amino acid sequences that exactly match iPLA(2)beta tryptic peptides. Peptide sequences identified in the 70 kDa tryptic digest include iPLA(2)beta residues 7-53, suggesting that the N-terminus is preserved. We also report here that the 832/13 INS-1 cells express iPLA(2)beta catalytic activity and that BEL inhibits secretagogue-stimulated insulin secretion from these cells but not the incorporation of arachidonic acid into membrane PC pools of these cells. These observations suggest that the catalytic iPLA(2)beta activity expressed in 832/13 INS-1 cells is attributable to a short isoform of iPLA(2)beta and that this isoform participates in insulin secretory but not in membrane phospholipid remodeling pathways. Further, the finding that pancreatic islets also express predominantly a 70 kDa iPLA(2)beta-immunoreactive protein suggests that a signal transduction role of iPLA(2)beta in the native beta-cell might be attributable to a 70 kDa isoform of iPLA(2)beta.

(beta)-catenin mediates the specification of endoderm cells in ascidian embryos.

PubMed

Imai, K; Takada, N; Satoh, N; Satou, Y

2000-07-01

In the present study, we addressed the role of (beta)-catenin in the specification of embryonic cells of the ascidians Ciona intestinalis and C. savignyi and obtained the following results: (1) During cleavages, (beta)-catenin accumulated in the nuclei of vegetal blastomeres, suggesting that it plays a role in the specification of endoderm. (2) Mis- and/or overexpression of (beta)-catenin induced the development of an endoderm-specific alkaline phosphatase (AP) in presumptive notochord cells and epidermis cells without affecting differentiation of primary lineage muscle cells. (3) Downregulation of (beta)-catenin induced by the overexpression of cadherin resulted in the suppression of endoderm cell differentiation. This suppression was compensated for by the differentiation of extra epidermis cells. (4) Specification of notochord cells did not take place in the absence of endoderm differentiation. Both the overexpression of (beta)-catenin in presumptive notochord cells and the downregulation of (beta)-catenin in presumptive endoderm cells led to the suppression of Brachyury gene expression, resulting in the failure of notochord specification. These results suggest that the accumulation of (beta)-catenin in the nuclei of endoderm progenitor cells is the first step in the process of ascidian endoderm specification.

Tumor-associated antigen human chorionic gonadotropin beta contains numerous antigenic determinants recognized by in vitro-induced CD8+ and CD4+ T lymphocytes.

PubMed

Dangles, Virginie; Halberstam, Ilan; Scardino, Antonio; Choppin, Jeannine; Wertheimer, Mireille; Richon, Sophie; Quelvennec, Erwann; Moirand, Romain; Guillet, Jean-Gérard; Kosmatopoulos, Kostas; Bellet, Dominique; Zeliszewski, Dominique

2002-02-01

The beta subunit of human chorionic gonadotropin (hCG beta) is markedly overexpressed by neoplastic cells of differing histological origin including those present in colon, breast, prostate and bladder tumors. We have previously shown that some patients with hCG beta-producing urothelial tumors have circulating T cells that proliferate in response to hCG beta. To make a comprehensive study of hCG beta as a potential target for cancer immunotherapy, we investigated whether hCG beta peptides could induce CD4+ or CD8+ T-cell responses in vitro. By stimulating peripheral blood mononuclear cells (PBMCs) from three donors with mixtures of overlapping 16-mer synthetic peptides analogous to portions of either the hCG beta 20-71 or the hCG beta 102-129 region, we established six CD4+ T-cell lines that proliferated specifically in response to five distinct determinants located within these two hCG beta regions. Three antigenic determinants (hCG beta 52-67, 106-121 and 114-125) were presented by HLA-DR molecules, while the two other antigenic determinants (hCG beta 48-63 and 56-67) were presented by HLA-DQ molecules. Interestingly, one T-cell line specific for peptide hCG beta 106-121 recognized hCG beta peptides comprising, at position 117, either an alanine or an aspartic acid residue, with the latter residue being present within the protein expressed by some tumor cells. In addition, three other hCG beta-derived peptides that exhibited HLA-A*0201 binding ability were able to stimulate CD8+ cytotoxic T cells from two HLA-A*0201 donors. These three immunogenic peptides corresponded to regions hCG beta 40-48, hCG beta 44-52 and hCG beta 75-84. Our results indicate that the tumor-associated antigen hCG beta possesses numerous antigenic determinants liable to stimulate CD4+ and CD8+ T lymphocytes, and might thus be an effective target antigen for the immunotherapy of hCG beta-producing tumors.

Retrograde transport of the transmembrane estrogen receptor, G-protein-coupled-receptor-30 (GPR30/GPER) from the plasma membrane towards the nucleus.

PubMed

Cheng, Shi-Bin; Graeber, Carl T; Quinn, Jeffrey A; Filardo, Edward J

2011-08-01

G-protein-coupled receptor 30 (GPR30/GPER) belongs to the seven transmembrane receptor (7TMR) superfamily, the most common class of surface receptor with approximately 800 known members. GPER promotes estrogen binding and rapid signaling via membrane-associated enzymes resulting in increased cAMP and release of heparan bound epidermal growth factor (proHB-EGF) from breast cancer cells. However, GPER is predominately localized intracellularly in breast cancer cells with minor amounts of receptor on the cell surface, an observation that has caused some controversy regarding its potential role as a plasma membrane estrogen receptor. Using the widely employed approach of tracking recombinant 7TMRs by surface labeling live cells, we have begun to characterize and compare the endocytic fate of GPER to other similarly labeled 7TMRs. Upon ectopic expression in human embryonic kidney HEK-293 cells, functional GPER is generated as these cells acquire the capacity to stimulate cAMP and activate cyclic AMP responsive binding protein in response to estradiol-17 beta stimulation. GPER is detectable on the cell surface by immunofluorescent analysis using HA-specific antibodies, albeit the bulk of the receptor is located intracellularly. Like β1AR (beta 1 adrenergic receptor) and CXCR4 (C-X-C chemokine receptor 4), GPER exits the plasma membrane via clathrin-coated pits and enters early endosomes. Interestingly, GPER has a destination that is uncommon among 7TMRs, as it accumulates in a perinuclear compartment. Like many 7TMRs (approximately one-third), GPER trafficking from the plasma membrane is constitutive (occurs in the absence of agonist). However, its route of intracellular trafficking is highly unusual, as 7TMRs typically recycle to the plasma membrane (e.g. β1AR) or are degraded in lysosomes (e.g. CXCR4). The accumulation of GPER in the perinuclear space and its possible significance for attenuating estrogen action via this newly recognized membrane estrogen receptor is discussed herein. Published by Elsevier Inc.

Immunological characterization of eristostatin and echistatin binding sites on alpha IIb beta 3 and alpha V beta 3 integrins.

PubMed Central

Marcinkiewicz, C; Rosenthal, L A; Mosser, D M; Kunicki, T J; Niewiarowski, S

1996-01-01

Two disintegrins with a high degree of amino acid sequence similarity, echistatin and eristostatin, showed a low level of interaction with Chinese hamster ovary (CHO) cells, but they bound to CHO cells transfected with alpha IIb beta 3 genes (A5 cells) and to CHO cells transfected with alpha v beta 3 genes (VNRC3 cells) in a reversible and saturable manner. Scatchard analysis revealed that eristostatin bound to 816000 sites per A5 cell (Kd 28 nM) and to 200000 sites (Kd 14 nM) per VNRC3 cell respectively. However, VNRC3 cells did not bind to immobilized eristostatin. Echistatin bound to 495000 sites (Kd 53 nM) per A5 cell and to 443000 sites (Kd 20 nM) per VNRC3 cell. As determined by flow cytometry, radiobinding assay and adhesion studies, binding of both disintegrins to A5 cells and resting platelets and binding of echistatin to VNRC3 cells resulted in the expression of ligand-induced binding sites (LIBS) on the beta 3 subunit. Eristostatin inhibited, more strongly than echistatin, the binding of three monoclonal antibodies: OPG2 (RGD motif dependent), A2A9 (alpha IIb beta 3 complex dependent) and 7E3 (alpha IIb beta 3 and alpha v beta 3 complex dependent) to A5 cells, to resting and to activated platelets and to purified alpha IIb beta 3. Experiments in which echistatin and eristostatin were used alone or in combination to inhibit the binding of 7E3 and OPG2 antibodies to resting platelets suggested that these two disintegrins bind to different but overlapping sites on alpha IIb beta 3 integrin. Monoclonal antibody LM 609 and echistatin seemed to bind to different sites on alpha v beta 3 integrin. However, echistatin inhibited binding of 7E3 antibody to VNRC3 cells and to purified alpha v beta 3 suggesting that alpha v beta 3 and alpha IIb beta 3 might share the same epitope to which both echistatin and 7E3 bind. Eristostatin had no effect in these systems, providing further evidence that it binds to a different epitope on alpha v beta 3. PMID:8760368

TGF-beta1 expression in EL4 lymphoma cells overexpressing growth hormone.

PubMed

Farmer, John T; Weigent, Douglas A

2006-03-01

Our previous studies show that growth hormone overexpression (GHo) upregulates the expression of the IGF-1R and IGF-2R resulting in the protection of the EL4 lymphoma cell line from apoptosis. In this study, we report that GHo also increases TGF-beta1 protein expression measured by luciferase promoter assay, Western analysis, and ELISA. Further, the data show that antibody to TGF-betaR2 decreases TGF-beta1 promoter activity to the level of vector alone control cells. GHo cells treated with (125)I-rh-latent TGF-beta1 showed increased activation of latent TGF-beta1 as measured by an increase in the active 24kDa, TGF-beta1 compared to vector alone control cells. The ability of endogenous GH to increase TGF-beta1 expression is blocked in EL4 cells by antisense but not sense oligodeoxynucleotides or in cells cultured with antibody to growth hormone (GH). The data suggest that endogenous GH may protect from apoptosis through the IGF-1R receptor while limiting cellular growth through increased expression and activation of TGF-beta1.

Activation of Beta-Catenin Signaling in Androgen Receptor–Negative Prostate Cancer Cells

PubMed Central

Wan, Xinhai; Liu, Jie; Lu, Jing-Fang; Tzelepi, Vassiliki; Yang, Jun; Starbuck, Michael W.; Diao, Lixia; Wang, Jing; Efstathiou, Eleni; Vazquez, Elba S.; Troncoso, Patricia; Maity, Sankar N.; Navone, Nora M.

2012-01-01

Purpose To study Wnt/beta-catenin in castrate-resistant prostate cancer (CRPC) and understand its function independently of the beta-catenin–androgen receptor (AR) interaction. Experimental Design We performed beta-catenin immunocytochemical analysis, evaluated TOP-flash reporter activity (a reporter of beta-catenin–mediated transcription), and sequenced the beta-catenin gene in MDA PCa 118a, MDA PCa 118b, MDA PCa 2b, and PC-3 prostate cancer (PCa) cells. We knocked down beta-catenin in AR-negative MDA PCa 118b cells and performed comparative gene-array analysis. We also immunohistochemically analyzed beta-catenin and AR in 27 bone metastases of human CRPCs. Results Beta-catenin nuclear accumulation and TOP-flash reporter activity were high in MDA PCa 118b but not in MDA PCa 2b or PC-3 cells. MDA PCa 118a and 118b cells carry a mutated beta-catenin at codon 32 (D32G). Ten genes were expressed differently (false discovery rate, 0.05) in MDA PCa 118b cells with downregulated beta-catenin. One such gene, hyaluronan synthase 2 (HAS2), synthesizes hyaluronan, a core component of the extracellular matrix. We confirmed HAS2 upregulation in PC-3 cells transfected with D32G-mutant beta-catenin. Finally, we found nuclear localization of beta-catenin in 10 of 27 human tissue specimens; this localization was inversely associated with AR expression (P = 0.056, Fisher’s exact test), suggesting that reduced AR expression enables Wnt/beta-catenin signaling. Conclusion We identified a previously unknown downstream target of beta-catenin, HAS2, in PCa, and found that high beta-catenin nuclear localization and low or no AR expression may define a subpopulation of men with bone-metastatic PCa. These findings may guide physicians in managing these patients. PMID:22298898

In situ hybridization analysis of anterior pituitary hormone gene expression during fetal mouse development.

PubMed

Japón, M A; Rubinstein, M; Low, M J

1994-08-01

We used 35S-labeled oligonucleotides and cRNAs (riboprobes) to detect the temporal order and spatial pattern of anterior pituitary hormone gene expression in (B6CBF1 x B6CBF1)F2 fetal mice from embryonic Day 9.5 (E9.5) to postnatal Day 1 (P1). Pro-opiomelanocortin (POMC) mRNA was expressed in the basal diencephalon on Day E10.5, in the ventromedial zone of the pars distalis on Day E12.5, and in the pars intermedia on Day E14.5. The common alpha-glycoprotein subunit (alpha-GSU) mRNA first appeared in the anterior wall of Rathke's pouch on Day E11.5 and extended to the pars tuberalis and ventromedial zone of the pars distalis on Day E12.5. Thyroid-stimulating hormone-beta (TSH beta) subunit mRNA was expressed initially in both the pas tuberalis and ventromedial pars distalis on Day E14.5, with an identical spatial distribution to alpha-GSU at the time. In contrast, luteinizing hormone-beta (LH beta) subunit and follicle-stimulating hormone beta (FSH beta) subunit mRNAs were detected initially only in the ventromedial pars distalis on Days E16.5 and E17.5, respectively, in an identical distribution to each other. POMC-, alpha-GSU-, TSH beta, LH beta-, and FSH beta-positive cells within the pars distalis all increased in number and autoradiographic signal with differing degrees of spatial expansion posteriorly, laterally, and dorsally up to Day P1. POMC expression was typically the most intense and extended circumferentially to include the entire lateral and dorsal surfaces of the pars distalis. The expression of both growth hormone (GH) and prolactin (PRL) started coincidentally on Day E15.5. However PRL cells localized in the ventromedial area similarly to POMC and the glycoprotein hormone subunits, whereas GH cells were found initially in a more lateral and central distribution within the lobes of the pars distalis. Somatotrophs increased dramatically in number and autoradiographic signal, extending throughout the pars distalis except for the most peripheral layer of cells on Day E17.5. Mammotrophs also increased in number but less abundantly than somatotrophs, and PRL expression remained more confined to central-medial and ventrolateral areas of the pars distalis up to Day P1. These data demonstrate distinctive patterns of expression for each of the major anterior pituitary hormone genes during development of the mouse pituitary gland and suggest that different groups of committed cells are the immediate precursors to the terminally differentiated hormone-secreting cell types.

Genetic models rule out a major role of beta cell glycogen in the control of glucose homeostasis.

PubMed

Mir-Coll, Joan; Duran, Jordi; Slebe, Felipe; García-Rocha, Mar; Gomis, Ramon; Gasa, Rosa; Guinovart, Joan J

2016-05-01

Glycogen accumulation occurs in beta cells of diabetic patients and has been proposed to partly mediate glucotoxicity-induced beta cell dysfunction. However, the role of glycogen metabolism in beta cell function and its contribution to diabetes pathophysiology remain poorly understood. We investigated the function of beta cell glycogen by studying glucose homeostasis in mice with (1) defective glycogen synthesis in the pancreas; and (2) excessive glycogen accumulation in beta cells. Conditional deletion of the Gys1 gene and overexpression of protein targeting to glycogen (PTG) was accomplished by Cre-lox recombination using pancreas-specific Cre lines. Glucose homeostasis was assessed by determining fasting glycaemia, insulinaemia and glucose tolerance. Beta cell mass was determined by morphometry. Glycogen was detected histologically by periodic acid-Schiff's reagent staining. Isolated islets were used for the determination of glycogen and insulin content, insulin secretion, immunoblots and gene expression assays. Gys1 knockout (Gys1 (KO)) mice did not exhibit differences in glucose tolerance or basal glycaemia and insulinaemia relative to controls. Insulin secretion and gene expression in isolated islets was also indistinguishable between Gys1 (KO) and controls. Conversely, despite effective glycogen overaccumulation in islets, mice with PTG overexpression (PTG(OE)) presented similar glucose tolerance to controls. However, under fasting conditions they exhibited lower glycaemia and higher insulinaemia. Importantly, neither young nor aged PTG(OE) mice showed differences in beta cell mass relative to age-matched controls. Finally, a high-fat diet did not reveal a beta cell-autonomous phenotype in either model. Glycogen metabolism is not required for the maintenance of beta cell function. Glycogen accumulation in beta cells alone is not sufficient to trigger the dysfunction or loss of these cells, or progression to diabetes.

Beta-type transforming growth factor specifies organizational behavior in vascular smooth muscle cell cultures

PubMed Central

1987-01-01

In culture, vascular smooth muscle cells (SMC) grow in a "hill-and- valley" (multilayered) pattern of organization. We have studied the growth, behavioral organization, and biosynthetic phenotype of rat aortic SMC exposed to purified platelet-derived growth regulatory molecules. We show that multilayered growth is not a constitutive feature of cultured SMC, and that beta-type transforming growth factor (TGF-beta) is the primary determinant of multilayered growth and the hill-and-valley pattern of organization diagnostic for SMC in culture. TGF-beta inhibited, in a dose-dependent manner, the serum- or platelet- derived growth factor-mediated proliferation of these cells in two- dimensional culture, but only when cells were plated at subconfluent densities. The ability of TGF-beta to inhibit SMC growth was inversely correlated to plating cell density. When SMC were plated at monolayer density (5 X 10(4) cells/cm2) to allow maximal cell-to-cell contact, TGF-beta potentiated cell growth. This differential response of SMC to TGF-beta may contribute to the hill-and-valley pattern of organization. Unlike its effect on other cell types, TGF-beta did not enhance the synthesis of fibronectin or its incorporation into the extracellular matrix. However, the synthesis of a number of other secreted proteins was altered by TGF-beta treatment. SMC treated with TGF-beta for 4 or 8 h secreted markedly enhanced amounts of an Mr 38,000-D protein doublet whose synthesis is known to be increased by heparin (another inhibitor of SMC growth), suggesting metabolic similarities between heparin- and TGF-beta-mediated SMC growth inhibition. The data suggest that TGF-beta may play an important and complex regulatory role in SMC proliferation and organization during development and after vascular injury. PMID:3475277

Stereolithographic models of the solvent-accessible surface of biopolymers. Topical report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bradford, J.; Noel, P.; Emery, J.D.

1996-11-01

The solvent-accessible surfaces of several biopolymers were calculated. As part of the DOE education outreach activity, two high school students participated in this project. Computer files containing sets of triangles were produced. These files are called stl files and are the ISO 9001 standard. They have been written onto CD-ROMs for distribution to American companies. Stereolithographic models were made of some of them to ensure that the computer calculations were done correctly. Stereolithographic models were made of interleukin 1{beta} (IL-1{beta}), three antibodies (an anti-p-azobenzene arsonate, an anti-Brucella A cell wall polysaccharide, and an HIV neutralizing antibody), a triple stranded coiledmore » coil, and an engrailed homeodomain. Also, the biopolymers and their files are described.« less

Structural analysis of N-linked glycans in Caenorhabditis elegans.

PubMed

Natsuka, Shunji; Adachi, Jiro; Kawaguchi, Masahumi; Nakakita, Shin-ichi; Hase, Sumihiro; Ichikawa, Akira; Ikura, Koji

2002-06-01

Caenorhabditis elegans is an excellent model for morphogenetic research. However, little information is available on the structure of cell-surface glycans in C. elegans, although several lines of evidence have suggested a role for these glycans in cell-cell interactions during development. In this study, we analyzed N-glycan structures. Oligosaccharides liberated by hydrazinolysis from a total membrane fraction were labeled by pyridylamination, and around 90% of the N-glycans were detected as neutral oligosaccharides. The most dominant structure was Man(alpha)1-6(Man(alpha)1-3)Man(beta)1-4GlcNAc(beta)1-4GlcNAc, which is commonly found in insects. Branching structures of major oligomannose-type glycans were the same as those found in mammals. Structures that had a core fucose or non-reducing end N-acetylglucosamine were also identified, but ordinary complex-type glycans with N-acetyllactosamine were not detected as major components.

Targeting of MPEG-protected polyamino acid carrier to human E-selectin in vitro.

PubMed

Kang, H W; Weissleder, R; Bogdanov, A

2002-01-01

Targeted diagnostic agents are expected to have a significant impact in molecular imaging of cell-surface associated markers of proliferation, inflammation and angiogenesis. In this communication, we describe a new class of targeted polyamino acid-based protected graft copolymers (PGC) of poly-(L-lysine) and methyl poly-(ethylene glycol) (PGC) covalently conjugated with a monoclonal antibody fragment, F(ab')(2). We utilized targeted PGC conjugates as carriers of near-infrared indocyanine fluorophores (Cy5.5) for optical imaging of endothelial cell populations expressing IL-1 beta inducible proinflammatory marker E-selectin. We compared two conjugation chemistries, involving either introduction of sulfhydryl group to F(ab')(2), or via direct attachment of the antibody fragment directly to the chemically activated PGC. Both PGC-based targeted agents demonstrated high binding specificity (20-30 fold over non-specific uptake) and were utilized for imaging E-selectin expression on human endothelial cells activated with IL-1 beta.

Modulation of epithelial sodium channel trafficking and function by sodium 4-phenylbutyrate in human nasal epithelial cells.

PubMed

Prulière-Escabasse, Virginie; Planès, Carole; Escudier, Estelle; Fanen, Pascale; Coste, André; Clerici, Christine

2007-11-23

Sodium 4-phenylbutyrate (4-PBA) has been shown to correct the cellular trafficking of several mutant or nonmutant plasma membrane proteins such as cystic fibrosis transmembrane conductance regulator through the expression of 70-kDa heat shock proteins. The objective of the study was to determine whether 4-PBA may influence the functional expression of epithelial sodium channels (ENaC) in human nasal epithelial cells (HNEC). Using primary cultures of HNEC, we demonstrate that 4-PBA (5 mm for 6 h) markedly stimulated amiloride-sensitive sodium channel activity and that this was related to an increased abundance of alpha-, beta-, and gamma-ENaC subunits in the apical membrane. The increase in ENaC cell surface expression (i) was due to insertion of newly ENaC subunits as determined by brefeldin A experiments and (ii) was not associated with cell surface retention of ENaC subunits because endocytosis of ENaC subunits was unchanged. In addition, we find that ENaC co-immunoprecipitated with the heat shock protein constitutively expressed Hsc70, that has been reported to modulate ENaC trafficking, and that 4-PBA decreased Hsc70 protein level. Finally, we report that in cystic fibrosis HNEC obtained from two cystic fibrosis patients, 4-PBA increased functional expression of ENaC as demonstrated by the increase in amiloride-sensitive sodium transport and in alpha-, beta-, and gamma-ENaC subunit expression in the apical membrane. Our results suggest that in HNEC, 4-PBA increases the functional expression of ENaC through the insertion of new alpha-, beta-, and gamma-ENaC subunits into the apical membrane and also suggest that 4-PBA could modify ENaC trafficking by reducing Hsc70 protein expression.

Localized immunosuppressive environment in the foreign body response to implanted biomaterials.

PubMed

Higgins, David M; Basaraba, Randall J; Hohnbaum, April C; Lee, Eric J; Grainger, David W; Gonzalez-Juarrero, Mercedes

2009-07-01

The implantation of synthetic biomaterials initiates the foreign body response (FBR), which is characterized by macrophage infiltration, foreign body giant cell formation, and fibrotic encapsulation of the implant. The FBR is orchestrated by a complex network of immune modulators, including diverse cell types, soluble mediators, and unique cell surface interactions. The specific tissue locations, expression patterns, and spatial distribution of these immune modulators around the site of implantation are not clear. This study describes a model for studying the FBR in vivo and specifically evaluates the spatial relationship of immune modulators. We modified a biomaterials implantation in vivo model that allowed for cross-sectional in situ analysis of the FBR. Immunohistochemical techniques were used to determine the localization of soluble mediators, ie, interleukin (IL)-4, IL-13, IL-10, IL-6, transforming growth factor-beta, tumor necrosis factor-alpha, interferon-gamma, and MCP-1; specific cell types, ie, macrophages, neutrophils, fibroblasts, and lymphocytes; and cell surface markers, ie, F4/80, CD11b, CD11c, and Ly-6C, at early, middle, and late stages of the FBR in subcutaneous implant sites. The cytokines IL-4, IL-13, IL-10, and transforming growth factor-beta were localized to implant-adherent cells that included macrophages and foreign body giant cells. A better understanding of the FBR in vivo will allow the development of novel strategies to enhance biomaterial implant design to achieve better performance and safety of biomedical devices at the site of implant.

Mechanistic studies of cancer cell mitochondria- and NQO1-mediated redox activation of beta-lapachone, a potentially novel anticancer agent

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Jason Z.; Ke, Yuebin; Misra, Hara P.

Beta-lapachone (beta-Lp) derived from the Lapacho tree is a potentially novel anticancer agent currently under clinical trials. Previous studies suggested that redox activation of beta-Lp catalyzed by NAD(P)H:quinone oxidoreductase 1 (NQO1) accounted for its killing of cancer cells. However, the exact mechanisms of this effect remain largely unknown. Using chemiluminescence and electron paramagnetic resonance (EPR) spin-trapping techniques, this study for the first time demonstrated the real-time formation of ROS in the redox activation of beta-lapachone from cancer cells mediated by mitochondria and NQO1 in melanoma B16–F10 and hepatocellular carcinoma HepG2 cancer cells. ES936, a highly selective NQO1 inhibitor, and rotenone,more » a selective inhibitor of mitochondrial electron transport chain (METC) complex I were found to significantly block beta-Lp meditated redox activation in B16–F10 cells. In HepG2 cells ES936 inhibited beta-Lp-mediated oxygen radical formation by ∼ 80% while rotenone exerted no significant effect. These results revealed the differential contribution of METC and NQO1 to beta-lapachone-induced ROS formation and cancer cell killing. In melanoma B16–F10 cells that do not express high NQO1 activity, both NOQ1 and METC play a critical role in beta-Lp redox activation. In contrast, in hepatocellular carcinoma HepG2 cells expressing extremely high NQO1 activity, redox activation of beta-Lp is primarily mediated by NQO1 (METC plays a minor role). These findings will contribute to our understanding of how cancer cells are selectively killed by beta-lapachone and increase our ability to devise strategies to enhance the anticancer efficacy of this potentially novel drug while minimizing its possible adverse effects on normal cells. - Highlights: • Both isolated mitochondria and purified NQO1 are able to generate ROS by beta-Lp. • The differential roles of mitochondria and NQO1 in mediating redox activation of beta-Lp • In cancer cells with low NQO1 expression, mitochondria play a critical role in beta-Lp redox activation. • In cancer cells with high NQO1 activity, redox activation of beta-Lp is primarily mediated by NQO1.« less

Hypoxia-inducible factor regulates alphavbeta3 integrin cell surface expression.

PubMed

Cowden Dahl, Karen D; Robertson, Sarah E; Weaver, Valerie M; Simon, M Celeste

2005-04-01

Hypoxia-inducible factor (HIF)-deficient placentas exhibit a number of defects, including changes in cell fate adoption, lack of fetal angiogenesis, hypocellularity, and poor invasion into maternal tissue. HIF is a heterodimeric transcription factor consisting of alpha and beta aryl hydrocarbon receptor nuclear translocator or ARNT) subunits. We used undifferentiated trophoblast stem (TS) cells to characterize HIF-dependent adhesion, migration, and invasion. Arnt(-/-) and Hifalpha(-/-) TS cells exhibit reduced adhesion and migration toward vitronectin compared with wild-type cells. Furthermore, this defect is associated with decreased cell surface expression of integrin alphavbeta3 and significantly decreased expression of this integrin in focal adhesions. Because of the importance of adhesion and migration in tumor progression (in addition to placental development), we examined the affect of culturing B16F0 melanoma cells in 1.5% oxygen (O(2)). Culturing B16F0 melanoma cells at 1.5% O(2) resulted in increased alphavbeta3 integrin surface expression and increased adhesion to and migration toward vitronectin. Together, these data suggest that HIF and O(2) tension influence placental invasion and tumor migration by increasing cell surface expression of alphavbeta3 integrin.

Application of a sodium sulfur cell with dynamic sulfur electrode to a battery system

NASA Astrophysics Data System (ADS)

Tokoi, H.; Takahashi, K.; Shimoyashiki, S.

1992-01-01

The construction and performance of a sodium sulfur battery system with dynamic sulfur electrodes are described. Three cells were first connected in parallel, then two such groups were connected in series. Each cell included a liquid sodium-filled beta-double-prime-alumina tube and a system to feed liquid sulfur into the annular cathode. Low-resistance graphite felt was tightly packed around the beta-double-prime-alumina tube. Sodium pentasulfide was removed from the sulfur electrode. The battery was operated automatically and stably charged and discharged in the two-phase region. The discharged energy was 4372 Wh (capacity 1170 Ah) during a continuous operation of 19.5 h. The discharge/charge energy efficiency of the battery was 82 percent at an averaged current density of 100 mA/sq cm and operating temperature of 350 C. The deviation of the cell current in a parallel chain was less than 7 percent, and this was induced by the difference in internal resistance. In the daily charge/discharge cycle, cell capacity with the dynamic sulfur electrode was 1.5 times higher than that with the static sulfur electrode using the same active surface of beta-double-prime-alumina, because the internal resistance of the former cell was constant regardless of cell capacity. This battery system with a dynamic sulfur electrode can be applied to energy storage systems,such as large scale load leveling systems, electric vehicle batteries, and solar energy systems.

Supramolecular structures on silica surfaces and their adsorptive properties.

PubMed

Belyakov, Vladimir N; Belyakova, Lyudmila A; Varvarin, Anatoly M; Khora, Olexandra V; Vasilyuk, Sergei L; Kazdobin, Konstantin A; Maltseva, Tetyana V; Kotvitskyy, Alexey G; Danil de Namor, Angela F

2005-05-01

The study of adsorptive and chemical immobilization of beta-cyclodextrin on a surface of hydroxylated silicas with various porous structure is described. Using IR spectroscopy, thermal gravimetrical analysis with a programmed heating, and chemical analysis of the silica surface, it is shown that the process of adsorption-desorption of beta-cyclodextrin depends on the porous structure of the silica. The reaction of esterification was used for chemical grafting of beta-cyclodextrin on the surface of hydroxylated silicas. Hydrolytic stability of silicas chemically modified by beta-cyclodextrin apparently is explained by simultaneous formation of chemical and hydrogen bonds between surface silanol groups and hydroxyl groups of beta-cyclodextrin. The uptake of the cations Cu(II), Cd(II), and Pb(II) and the anions Cr(VI) and As(V) by silicas modified with beta-cyclodextrin is investigated as a function of equilibrium ion concentrations. The increase of ion uptake and selectivity of ion extraction in comparison with starting silicas is established. It is due to the formation of surface inclusion complexes of the "host-guest" type in which one molecule of beta-cyclodextrin interacts simultaneously with several ions.

Chronology of endocrine differentiation and beta-cell neogenesis.

PubMed

Miyatsuka, Takeshi

2016-01-01

Diabetes is a chronic and incurable disease, which results from absolute or relative insulin insufficiency. Therefore, pancreatic beta cells, which are the only type of cell that expresses insulin, is considered to be a potential target for the cure of diabetes. Although the findings regarding beta-cell neogenesis during pancreas development have been exploited to induce insulin-producing cells from non-beta cells, there are still many hurdles towards generating fully functional beta cells that can produce high levels of insulin and respond to physiological signals. To overcome these problems, a solid understanding of pancreas development and beta-cell formation is required, and several mouse models have been developed to reveal the unique features of each endocrine cell type at distinct developmental time points. Here I review our understanding of pancreas development and endocrine differentiation focusing on recent progresses in improving temporal cell labeling in vivo.

Transforming growth factor-beta controls T helper type 1 cell development through regulation of natural killer cell interferon-gamma.

PubMed

Laouar, Yasmina; Sutterwala, Fayyaz S; Gorelik, Leonid; Flavell, Richard A

2005-06-01

Interferon-gamma and interleukin 12 produced by the innate arm of the immune system are important regulators of T helper type 1 (T(H)1) cell development, but signals that negatively regulate their expression remain controversial. Here we show that transforming growth factor-beta (TGF-beta) controlled T(H)1 differentiation through the regulation of interferon-gamma produced by natural killer (NK) cells. Blockade of TGF-beta signaling in NK cells caused the accumulation of a large pool of NK cells secreting copious interferon-gamma, responsible for T(H)1 differentiation and protection from leishmania infection. In contrast, blockade of TGF-beta signaling in dendritic cells did not affect dendritic cell homeostasis or interleukin 12 production, thus indicating a previously undescribed demarcation of the function of TGF-beta in NK cells versus dendritic cells.

The quest to make fully functional human pancreatic beta cells from embryonic stem cells: climbing a mountain in the clouds.

PubMed

Johnson, James D

2016-10-01

The production of fully functional insulin-secreting cells to treat diabetes is a major goal of regenerative medicine. In this article, I review progress towards this goal over the last 15 years from the perspective of a beta cell biologist. I describe the current state-of-the-art, and speculate on the general approaches that will be required to identify and achieve our ultimate goal of producing functional beta cells. The need for deeper phenotyping of heterogeneous cultures of stem cell derived islet-like cells in parallel with a better understanding of the heterogeneity of the target cell type(s) is emphasised. This deep phenotyping should include high-throughput single-cell analysis, as well as comprehensive 'omics technologies to provide unbiased characterisation of cell products and human beta cells. There are justified calls for more detailed and well-powered studies of primary human pancreatic beta cell physiology, and I propose online databases of standardised human beta cell responses to physiological stimuli, including both functional and metabolomic/proteomic/transcriptomic profiles. With a concerted, community-wide effort, including both basic and applied scientists, beta cell replacement will become a clinical reality for patients with diabetes.

Isolation and characterization of distinct domains of sarcolemma and T-tubules from rat skeletal muscle.

PubMed

Muñoz, P; Rosemblatt, M; Testar, X; Palacín, M; Zorzano, A

1995-04-01

1. Several cell-surface domains of sarcolemma and T-tubule from skeletal-muscle fibre were isolated and characterized. 2. A protocol of subcellular fractionation was set up that involved the sequential low- and high-speed homogenization of rat skeletal muscle followed by KCl washing, Ca2+ loading and sucrose-density-gradient centrifugation. This protocol led to the separation of cell-surface membranes from membranes enriched in sarcoplasmic reticulum and intracellular GLUT4-containing vesicles. 3. Agglutination of cell-surface membranes using wheat-germ agglutinin allowed the isolation of three distinct cell-surface membrane domains: sarcolemmal fraction 1 (SM1), sarcolemmal fraction 2 (SM2) and a T-tubule fraction enriched in protein tt28 and the alpha 2-component of dihydropyridine receptor. 4. Fractions SM1 and SM2 represented distinct sarcolemmal subcompartments based on different compositions of biochemical markers: SM2 was characterized by high levels of beta 1-integrin and dystrophin, and SM1 was enriched in beta 1-integrin but lacked dystrophin. 5. The caveolae-associated molecule caveolin was very abundant in SM1, SM2 and T-tubules, suggesting the presence of caveolae or caveolin-rich domains in these cell-surface membrane domains. In contrast, clathrin heavy chain was abundant in SM1 and T-tubules, but only trace levels were detected in SM2. 6. Immunoadsorption of T-tubule vesicles with antibodies against protein tt28 and against GLUT4 revealed the presence of GLUT4 in T-tubules under basal conditions and it also allowed the identification of two distinct pools of T-tubules showing different contents of tt28 and dihydropyridine receptors. 7. Our data on distribution of clathrin and dystrophin reveal the existence of subcompartments in sarcolemma from muscle fibre, featuring selective mutually exclusive components. T-tubules contain caveolin and clathrin suggesting that they contain caveolin- and clathrin-rich domains. Furthermore, evidence for the heterogeneous distribution of membrane proteins in T-tubules is also presented.

Regulation of pancreatic islet beta-cell mass by growth factor and hormone signaling.

PubMed

Huang, Yao; Chang, Yongchang

2014-01-01

Dysfunction and destruction of pancreatic islet beta cells is a hallmark of diabetes. Better understanding of cellular signals in beta cells will allow development of therapeutic strategies for diabetes, such as preservation and expansion of beta-cell mass and improvement of beta-cell function. During the past several decades, the number of studies analyzing the molecular mechanisms, including growth factor/hormone signaling pathways that impact islet beta-cell mass and function, has increased exponentially. Notably, somatolactogenic hormones including growth hormone (GH), prolactin (PRL), and insulin-like growth factor-1 (IGF-1) and their receptors (GHR, PRLR, and IGF-1R) are critically involved in beta-cell growth, survival, differentiation, and insulin secretion. In this chapter, we focus more narrowly on GH, PRL, and IGF-1 signaling, and GH-IGF-1 cross talk. We also discuss how these signaling aspects contribute to the regulation of beta-cell proliferation and apoptosis. In particular, our novel findings of GH-induced formation of GHR-JAK2-IGF-1R protein complex and synergistic effects of GH and IGF-1 on beta-cell signaling, proliferation, and antiapoptosis lead to a new concept that IGF-1R may serve as a proximal component of GH/GHR signaling. © 2014 Elsevier Inc. All rights reserved.

Topologically heterogeneous beta cell adaptation in response to high-fat diet in mice.

PubMed

Ellenbroek, Johanne H; Töns, Hendrica A; de Graaf, Natascha; Loomans, Cindy J; Engelse, Marten A; Vrolijk, Hans; Voshol, Peter J; Rabelink, Ton J; Carlotti, Françoise; de Koning, Eelco J

2013-01-01

Beta cells adapt to an increased insulin demand by enhancing insulin secretion via increased beta cell function and/or increased beta cell number. While morphological and functional heterogeneity between individual islets exists, it is unknown whether regional differences in beta cell adaptation occur. Therefore we investigated beta cell adaptation throughout the pancreas in a model of high-fat diet (HFD)-induced insulin resistance in mice. C57BL/6J mice were fed a HFD to induce insulin resistance, or control diet for 6 weeks. The pancreas was divided in a duodenal (DR), gastric (GR) and splenic (SR) region and taken for either histology or islet isolation. The capacity of untreated islets from the three regions to adapt in an extrapancreatic location was assessed by transplantation under the kidney capsule of streptozotocin-treated mice. SR islets showed 70% increased beta cell proliferation after HFD, whereas no significant increase was found in DR and GR islets. Furthermore, isolated SR islets showed twofold enhanced glucose-induced insulin secretion after HFD, as compared with DR and GR islets. In contrast, transplantation of islets isolated from the three regions to an extrapancreatic location in diabetic mice led to a similar decrease in hyperglycemia and no difference in beta cell proliferation. HFD-induced insulin resistance leads to topologically heterogeneous beta cell adaptation and is most prominent in the splenic region of the pancreas. This topological heterogeneity in beta cell adaptation appears to result from extrinsic factors present in the islet microenvironment.

Specific signals involved in the long-term maintenance of radiation-induced fibrogenic differentiation: a role for CCN2 and low concentration of TGF-beta1.

PubMed

Haydont, Valérie; Riser, Bruce L; Aigueperse, Jocelyne; Vozenin-Brotons, Marie-Catherine

2008-06-01

The fibrogenic differentiation of resident mesenchymal cells is a key parameter in the pathogenesis of radiation fibrosis and is triggered by the profibrotic growth factors transforming growth factor (TGF)-beta1 and CCN2. TGF-beta1 is considered the primary inducer of fibrogenic differentiation and is thought to control its long-term maintenance, whereas CCN2 is considered secondary effector of TGF-beta1. Yet, in long-term established fibrosis like that associated with delayed radiation enteropathy, in situ TGF-beta1 deposition is low, whereas CCN2 expression is high. To explore this apparent paradox, cell response to increasing doses of TGF-beta1 was investigated in cells modeling initiation and maintenance of fibrosis, i.e., normal and fibrosis-derived smooth muscle cells, respectively. Activation of cell-specific signaling pathways by low TGF-beta1 doses was demonstrated with a main activation of the Rho/ROCK pathway in fibrosis-derived cells, whereas the Smad pathway was mainly activated in normal cells. This leads to subsequent and cell-specific regulation of the CCN2 gene. These results suggested a specific profibrotic role of CCN2 in fibrosis-initiated cells. Furthermore, the modulation of CCN2 expression by itself and the combination of TGF-beta1 and CCN2 was investigated in fibrosis-derived cells. In fibrosis-initiated cells CCN2 triggered its autoinduction; furthermore, low concentration of TGF-beta1-potentiated CCN2 autoinduction. Our findings showed a differential requirement and action of TGF-beta1 in the fibrogenic response of normal vs. fibrosis-derived cells. This study defines a novel Rho/ROCK but Smad3-independent mode of TGF-beta signaling that may operate during the chronic stages of fibrosis and provides evidence of both specific and combinatorial roles of low TGF-beta1 dose and CCN2.

Sulfatide promotes the folding of proinsulin, preserves insulin crystals, and mediates its monomerization.

PubMed

Osterbye, T; Jørgensen, K H; Fredman, P; Tranum-Jensen, J; Kaas, A; Brange, J; Whittingham, J L; Buschard, K

2001-06-01

Sulfatide is a glycolipid that has been associated with insulin-dependent diabetes mellitus. It is present in the islets of Langerhans and follows the same intracellular route as insulin. However, the role of sulfatide in the beta cell has been unclear. Here we present evidence suggesting that sulfatide promotes the folding of reduced proinsulin, indicating that sulfatide possesses molecular chaperone activity. Sulfatide associates with insulin by binding to the insulin domain A8--A10 and most likely by interacting with the hydrophobic side chains of the dimer-forming part of the insulin B-chain. Sulfatide has a dual effect on insulin. It substantially reduces deterioration of insulin hexamer crystals at pH 5.5, conferring stability comparable to those in beta cell granules. Sulfatide also mediates the conversion of insulin hexamers to the biological active monomers at neutral pH, the pH at the beta-cell surface. Finally, we report that inhibition of sulfatide synthesis with chloroquine and fumonisine B1 leads to inhibition of insulin granule formation in vivo. Our observations suggest that sulfatide plays a key role in the folding of proinsulin, in the maintenance of insulin structure, and in the monomerization process.

Cell-type specific effects of endocytosis inhibitors on 5-hydroxytryptamine(2A) receptor desensitization and resensitization reveal an arrestin-, GRK2-, and GRK5-independent mode of regulation in human embryonic kidney 293 cells.

PubMed

Gray, J A; Sheffler, D J; Bhatnagar, A; Woods, J A; Hufeisen, S J; Benovic, J L; Roth, B L

2001-11-01

The effect of endocytosis inhibitors on 5-hydroxytryptamine(2A) (5-HT(2A)) receptor desensitization and resensitization was examined in transiently transfected human embryonic kidney (HEK) 293 cells and in C6 glioma cells that endogenously express 5-HT(2A) receptors. In HEK-293 cells, 5-HT(2A) receptor desensitization was unaffected by cotransfection with a dominant-negative mutant of dynamin (DynK44A), a truncation mutant of arrestin-2 [Arr2(319-418)], or by two well-characterized chemical inhibitors of endocytosis: concanavalin A (conA) and phenylarsine oxide (PAO). In contrast, beta 2-adrenergic receptor desensitization was significantly potentiated by each of these treatments in HEK-293 cells. In C6 glioma cells, however, DynK44A, Arr2(319-418), conA, and PAO each resulted in the potentiation of 5-HT(2A) and beta-adrenergic receptor desensitization. The cell-type-specific effect of Arr2(319-418) on 5-HT(2A) receptor desensitization was not related to the level of GRK2 or GRK5 expression. Interestingly, although beta 2-adrenergic receptor resensitization was potently blocked by cotransfection with DynK44A, 5-HT(2A) receptor resensitization was enhanced, suggesting the existence of a novel cell-surface mechanism for 5-HT(2A) receptor resensitization in HEK-293 cells. In addition, Arr2(319-418) had no effect on 5-HT(2A) receptor resensitization in HEK-293 cells, although it attenuated the resensitization of the beta 2-adrenergic receptor. However, in C6 glioma cells, both DynK44A and Arr2(319-418) significantly reduced 5-HT(2A) receptor resensitization. Taken together, these results provide the first convincing evidence of cell-type-specific roles for endocytosis inhibitors in regulating GPCR activity. Additionally, these results imply that novel GRK and arrestin-independent mechanisms of 5-HT(2A) receptor desensitization and resensitization exist in HEK-293 cells.

[Isolation, purification and primary culture of rat pancreatic beta-cells].

PubMed

Liu, Yu-Pu; Lü, Qing-Guo; Tong, Nan-Wei

2009-01-01

To isolate and purify rat pancreatic beta-cells and to explore the best conditions for the primary culture of the pancreatic beta-cells in vitro. The pancreas of Norman Wistar rats were digested by collagenase V. The islets were purified by mesh sieve. The activity of the islets was stimulated by different concentrations of glucose and detected by dithizone dye. The purified islets were put into RPMI-1640 nutritive medium for culture overnight. The cultured islets were digested again with trypsin and DNAase to obtain the suspension containing single pancreatic cells. The beta-cells were separated and purified in a fluorescence-activated cell sorter (FACS) in the medium containing 2.8 mmol/L glucose. The purified beta-cells were identified by immunohistochemistry and glucose stimulating test. Ham's F-10 with different concentrations of glucose and 3-Isobutyl-1-methylxanthine (IBMX) were used as nutritive medium for the primary cell culture for 24 hours. The best conditions for the culture were identified. An average of 550 +/- 90 islets with fine activities were obtained per rat. The purification with FACS obtained about 5688 beta-cells per rat, with a recovery rate of (93.69 +/- 1.26)% and a purity of (85.5 +/- 1.24)%. A concentration of 10.0 mmol/L and 16.0 mmol/L glucose in primary culture for 24 hours produced the highest survival rates of beta-cells, but IBMX did not increase the survival rates of beta-cells. FACS is effective in purifying pancreatic beta-cells from the suspension with a medium containing 2.8 mmol/L glucose. Pancreatic beta-cells maintain relatively high activities in Ham's F-10 medium containing 10.0-16.0 mmol/L glucose in primary culture.

Normal T lymphocytes can express two different T cell receptor beta chains: implications for the mechanism of allelic exclusion

PubMed Central

1995-01-01

We have examined the extent of allelic exclusion at the T cell receptor (TCR) beta locus using monoclonal antibodies specific for V beta products. A small proportion (approximately 1%) of human peripheral blood T cells express two V beta as determined by flow cytometric analysis, isolation of representative clones, and sequencing of the corresponding V beta chains. Dual beta T cells are present in both the CD45R0+ and CD45R0- subset. These results indicate that dual beta expression is compatible with both central and peripheral selection. They also suggest that the substantial degree of TCR beta allelic exclusion is dependent only on asynchronous rearrangements at the beta locus, whereas the role of the pre-TCR is limited to signaling the presence of at least one functional beta protein. PMID:7699339

Activation of the canonical beta-catenin pathway by histamine.

PubMed

Diks, Sander H; Hardwick, James C; Diab, Remco M; van Santen, Marije M; Versteeg, Henri H; van Deventer, Sander J H; Richel, Dick J; Peppelenbosch, Maikel P

2003-12-26

Histamine signaling is a principal regulator in a variety of pathophysiological processes including inflammation, gastric acid secretion, neurotransmission, and tumor growth. We report that histamine stimulation causes transactivation of a T cell factor/beta-catenin-responsive construct in HeLa cells and in the SW-480 colon cell line, whereas histamine did not effect transactivation of a construct containing the mutated response construct FOP. On the protein level, histamine treatment increases phosphorylation of glycogen synthase kinase 3-beta in HeLa cells, murine macrophages, and DLD-1, HT-29, and SW-480 colon cell lines. Furthermore, histamine also decreases the phosphorylated beta-catenin content in HeLa cells and murine macrophages. Finally, pharmacological inhibitors of the histamine H1 receptor counteracted histamine-induced T cell factor/beta-catenin-responsive construct transactivation and the dephosphorylation of beta-catenin in HeLa cells and in macrophages. We conclude that the canonical beta-catenin pathway acts downstream of the histamine receptor H1 in a variety of cell types. The observation that inflammatory molecules, like histamine, activate the beta-catenin pathway may provide a molecular explanation for a possible link between inflammation and cancer.

Cellular Behavior of Human Adipose-Derived Stem Cells on Wettable Gradient Polyethylene Surfaces

PubMed Central

Ahn, Hyun Hee; Lee, Il Woo; Lee, Hai Bang; Kim, Moon Suk

2014-01-01

Appropriate surface wettability and roughness of biomaterials is an important factor in cell attachment and proliferation. In this study, we investigated the correlation between surface wettability and roughness, and biological response in human adipose-derived stem cells (hADSCs). We prepared wettable and rough gradient polyethylene (PE) surfaces by increasing the power of a radio frequency corona discharge apparatus with knife-type electrodes over a moving sample bed. The PE changed gradually from hydrophobic and smooth surfaces to hydrophilic (water contact angle, 90º to ~50º) and rough (80 to ~120 nm) surfaces as the power increased. We found that hADSCs adhered better to highly hydrophilic and rough surfaces and showed broadly stretched morphology compared with that on hydrophobic and smooth surfaces. The proliferation of hADSCs on hydrophilic and rough surfaces was also higher than that on hydrophobic and smooth surfaces. Furthermore, integrin beta 1 gene expression, an indicator of attachment, and heat shock protein 70 gene expression were high on hydrophobic and smooth surfaces. These results indicate that the cellular behavior of hADSCs on gradient surface depends on surface properties, wettability and roughness. PMID:24477265

The glucagon-miniglucagon interplay: a new level in the metabolic regulation.

PubMed

Bataille, Dominique; Fontés, Ghislaine; Costes, Safia; Longuet, Christine; Dalle, Stéphane

2006-07-01

Miniglucagon (glucagon 19-29) is the ultimate processing product of proglucagon, present in the glucagon-secreting granules of the alpha cells, at a close vicinity of the insulin-secreting beta cells. Co-released with glucagon and thanks to its original mode of action and its huge potency, it suppresses, inside the islet of Langerhans, the detrimental effect of glucagon on insulin secretion, while it leaves untouched the beneficial effect of glucagon on glucose competence of the beta cell. At the periphery, miniglucagon is processed at the surface of glucagon- and insulin-sensitive cells from circulating glucagon. At that level, it acts via a cellular pathway which uses initial molecular steps distinct from that of insulin which, when impaired, are involved in insulin resistence. This bypass allows miniglucagon to act as an insulin-like component, a characteristic which makes this peptide of particular interest from a pathophysiological and pharmacological point of views in understanding and treating metabolic diseases, such as the type 2 diabetes.

Quantitative Impact of Plasma Clearance and Down-regulation on GLP-1 Receptor Molecular Imaging.

PubMed

Zhang, Liang; Thurber, Greg M

2016-02-01

Quantitative molecular imaging of beta cell mass (BCM) would enable early detection and treatment monitoring of type 1 diabetes. The glucagon-like peptide-1 (GLP-1) receptor is an attractive target due to its beta cell specificity and cell surface location. We quantitatively investigated the impact of plasma clearance and receptor internalization on targeting efficiency in healthy B6 mice. Four exenatide-based probes were synthesized that varied in molecular weight, binding affinity, and plasma clearance. The GLP-1 receptor internalization rate and in vivo receptor expression were quantified. Receptor internalization (54,000 receptors/cell in vivo) decreased significantly within minutes, reducing the benefit of a slower-clearing agent. The multimers and albumin binding probes had higher kidney and liver uptake, respectively. Slow plasma clearance is beneficial for GLP-1 receptor peptide therapeutics. However, for exendin-based imaging of islets, down-regulation of the GLP-1 receptor and non-specific background uptake result in a higher target-to-background ratio for fast-clearing agents.

Quantitative Impact of Plasma Clearance and Down-regulation on GLP-1 Receptor Molecular Imaging

PubMed Central

Zhang, Liang; Thurber, Greg M.

2016-01-01

Purpose Quantitative molecular imaging of beta cell mass (BCM) would enable early detection and treatment monitoring of type-1 diabetes. The glucagon like peptide-1 (GLP-1) receptor is an attractive target due to its beta cell specificity and cell surface location. We quantitatively investigated the impact of plasma clearance and receptor internalization on targeting efficiency in healthy B6 mice. Procedures Four exenatide-based probes were synthesized that varied in molecular weight, binding affinity, and plasma clearance. The GLP-1 receptor internalization rate and in vivo receptor expression were quantified. Results Receptor internalization (54,000 receptors/cell in vivo) decreased significantly within minutes, reducing the benefit of a slower clearing agent. The multimers and albumin binding probes had higher kidney and liver uptake, respectively. Conclusions Slow plasma clearance is beneficial for GLP-1 receptor peptide therapeutics. However, for exendin-based imaging of islets, downregulation of the GLP-1 receptor and non-specific background uptake result in a higher TBR for fast-clearing agents. PMID:26194012

A structural basis for antigen recognition by the T cell-like lymphocytes of sea lamprey

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deng, Lu; Velikovsky, C. Alejandro; Xu, Gang

Adaptive immunity in jawless vertebrates is mediated by leucine-rich repeat proteins called 'variable lymphocyte receptors' (VLRs). Two types of VLR (A and B) are expressed by mutually exclusive lymphocyte populations in lamprey. VLRB lymphocytes resemble the B cells of jawed vertebrates; VLRA lymphocytes are similar to T cells. We determined the structure of a high-affinity VLRA isolated from lamprey immunized with hen egg white lysozyme (HEL) in unbound and antigen-bound forms. The VLRA-HEL complex demonstrates that certain VLRAs, like {gamma}{delta} T-cell receptors (TCRs) but unlike {alpha}{beta} TCRs, can recognize antigens directly, without a requirement for processing or antigen-presenting molecules. Thus,more » these VLRAs feature the nanomolar affinities of antibodies, the direct recognition of unprocessed antigens of both antibodies and {gamma}{delta} TCRs, and the exclusive expression on the lymphocyte surface that is unique to {alpha}{beta} and {gamma}{delta} TCRs.« less

E-cadherin and cell adhesion: a role in architecture and function in the pancreatic islet.

PubMed

Rogers, Gareth J; Hodgkin, Matthew N; Squires, Paul E

2007-01-01

The efficient secretion of insulin from beta-cells requires extensive intra-islet communication. The cell surface adhesion protein epithelial (E)-cadherin (ECAD) establishes and maintains epithelial tissues such as the islets of Langerhans. In this study, the role of ECAD in regulating insulin secretion from pseudoislets was investigated. The effect of an immuno-neutralising ECAD on gross morphology, cytosolic calcium signalling, direct cell-to-cell communication and insulin secretion was assessed by fura-2 microfluorimetry, Lucifer Yellow dye injection and insulin ELISA in an insulin-secreting model system. Antibody blockade of ECAD reduces glucose-evoked changes in [Ca(2+)](i) and insulin secretion. Neutralisation of ECAD causes a breakdown in the glucose-stimulated synchronicity of calcium oscillations between discrete regions within the pseudoislet, and the transfer of dye from an individual cell within a cell cluster is attenuated in the absence of ECAD ligation, demonstrating that gap junction communication is disrupted. The functional consequence of neutralising ECAD is a significant reduction in insulin secretion. Cell adhesion via ECAD has distinct roles in the regulation of intercellular communication between beta-cells within islets, with potential repercussions for insulin secretion.

The islet beta-cell: fuel responsive and vulnerable.

PubMed

Nolan, Christopher J; Prentki, Marc

2008-10-01

The pancreatic beta-cell senses blood nutrient levels and is modulated by neurohormonal signals so that it secretes insulin according to the need of the organism. Nutrient sensing involves marked metabolic activation, resulting in the production of coupling signals that promote insulin biosynthesis and secretion. The beta-cell's high capacity for nutrient sensing, however, necessitates reduced protection to nutrient toxicity. This potentially explains why in susceptible individuals, chronic fuel surfeit results in beta-cell failure and type 2 diabetes. Here we discuss recent insights into first, the biochemical basis of beta-cell signaling in response to glucose, amino acids and fatty acids, and second, beta-cell nutrient detoxification. We emphasize the emerging role of glycerolipid/fatty acid cycling in these processes.

Apparent inhibition of. beta. -fructosidase secretion by tunicamycin may be explained by breakdown of the unglycosylated protein during secretion. [Daucus carota

DOE Office of Scientific and Technical Information (OSTI.GOV)

Faye, L.; Chrispeels, M.J.

1989-03-01

Suspension-cultured carrot (Daucus carota) cells synthesize and secrete {beta}-fructosidase, a glycoprotein with asparagine-linked glycans. Treatment of the cells with tunicamycin completely inhibits the apparent secretion of {beta}-fructosidase as measured by the accumulation of the {sup 35}S-labelled protein in the cell wall or the culture medium. In the past, such a result has been interpreted as an inhibition of secretion by tunicamycin, but we suggest another explanation based on the following results. In the presence of tunicamycin, unglycosylated {beta}-fructosidase is synthesized and is associated with an endoplasmic-reticulum-rich microsomal fraction. Pulse-chase experiments show that the unglycosylated {beta}-fructosidase does not remain in themore » cells and appears to be secreted in the same way as glycosylated {beta}-fructosidase; however, no radioactive, unglycosylated {beta}-fructosidase accumulates extracellularly (cell wall or medium). Protoplasts obtained from carrot cells secrete {beta}-fructosidase protein and activity, and treatment of the protoplasts with tunicamycin results in the synthesis of unglycosylated {beta}-fructosidase. In the presence of tunicamycin, there is no accumulation of {beta}-fructosidase activity or unglycosylated {beta}-fructosidase polypeptide in the protoplast incubation medium. These results are consistent with the interpretation that the glycans of {beta}-fructosidase are necessary for its stability, and that in these suspension-cultured cells, the unglycosylated enzyme is degraded during the last stage(s) of secretion, or immediately after its arrival in the wall.« less

Betavoltaics using scandium tritide and contact potential difference

NASA Astrophysics Data System (ADS)

Liu, Baojun; Chen, Kevin P.; Kherani, Nazir P.; Zukotynski, Stefan; Antoniazzi, Armando B.

2008-02-01

Tritium-powered betavoltaic micropower sources using contact potential difference (CPD) are demonstrated. Thermally stable scandium tritide thin films with a surface activity of 15mCi/cm2 were used as the beta particle source. The electrical field created by the work function difference between the ScT film and a platinum or copper electrode was used to separate the beta-generated electrical charge carriers. Open circuit voltages of 0.5 and 0.16V and short circuit current densities of 2.7 and 5.3nA/cm2 were achieved for gaseous and solid dielectric media-based CPD cells, respectively.

Pancreatic Beta Cells Synthesize Neuropeptide Y and Can Rapidly Release Peptide Co-Transmitters

PubMed Central

Whim, Matthew D.

2011-01-01

Background In addition to polypeptide hormones, pancreatic endocrine cells synthesize a variety of bioactive molecules including classical transmitters and neuropeptides. While these co-transmitters are thought to play a role in regulating hormone release little is known about how their secretion is regulated. Here I investigate the synthesis and release of neuropeptide Y from pancreatic beta cells. Methodology/Principal Findings NPY appears to be an authentic co-transmitter in neonatal, but not adult, beta cells because (1) early in mouse post-natal development, many beta cells are NPY-immunoreactive whereas no staining is observed in beta cells from NPY knockout mice; (2) GFP-expressing islet cells from an NPY(GFP) transgenic mouse are insulin-ir; (3) single cell RT-PCR experiments confirm that the NPY(GFP) cells contain insulin mRNA, a marker of beta cells. The NPY-immunoreactivity previously reported in alpha and delta cells is therefore likely to be due to the presence of NPY-related peptides. INS-1 cells, a beta cell line, are also NPY-ir and contain NPY mRNA. Using the FMRFamide tagging technique, NPY secretion was monitored from INS-1 beta cells with high temporal resolution. Peptide release was evoked by brief depolarizations and was potentiated by activators of adenylate cyclase and protein kinase A. Following a transient depolarization, NPY-containing dense core granules fused with the cell membrane and discharged their contents within a few milliseconds. Conclusions These results indicate that after birth, NPY expression in pancreatic islets is restricted to neonatal beta cells. The presence of NPY suggests that peptide co-transmitters could mediate rapid paracrine or autocrine signaling within the endocrine pancreas. The FMRFamide tagging technique may be useful in studying the release of other putative islet co-transmitters in real time. PMID:21559341

Calbindin-D(28k) controls [Ca(2+)](i) and insulin release. Evidence obtained from calbindin-d(28k) knockout mice and beta cell lines

NASA Technical Reports Server (NTRS)

Sooy, K.; Schermerhorn, T.; Noda, M.; Surana, M.; Rhoten, W. B.; Meyer, M.; Fleischer, N.; Sharp, G. W.; Christakos, S.

1999-01-01

The role of the calcium-binding protein, calbindin-D(28k) in potassium/depolarization-stimulated increases in the cytosolic free Ca(2+) concentration ([Ca(2+)](i)) and insulin release was investigated in pancreatic islets from calbindin-D(28k) nullmutant mice (knockouts; KO) or wild type mice and beta cell lines stably transfected and overexpressing calbindin. Using single islets from KO mice and stimulation with 45 mM KCl, the peak of [Ca(2+)](i) was 3.5-fold greater in islets from KO mice compared with wild type islets (p < 0.01) and [Ca(2+)](i) remained higher during the plateau phase. In addition to the increase in [Ca(2+)](i) in response to KCl there was also a significant increase in insulin release in islets isolated from KO mice. Evidence for modulation by calbindin of [Ca(2+)](i) and insulin release was also noted using beta cell lines. Rat calbindin was stably expressed in betaTC-3 and betaHC-13 cells. In response to depolarizing concentrations of K(+), insulin release was decreased by 45-47% in calbindin expressing betaTC cells and was decreased by 70-80% in calbindin expressing betaHC cells compared with insulin release from vector transfected betaTC or betaHC cells (p < 0.01). In addition, the K(+)-stimulated intracellular calcium peak was markedly inhibited in calbindin expressing betaHC cells compared with vector transfected cells (225 nM versus 1,100 nM, respectively). Buffering of the depolarization-induced rise in [Ca(2+)](i) was also observed in calbindin expressing betaTC cells. In summary, our findings, using both isolated islets from calbindin-D(28k) KO mice and beta cell lines, establish a role for calbindin in the modulation of depolarization-stimulated insulin release and suggest that calbindin can control the rate of insulin release via regulation of [Ca(2+)](i).

SIRT6-mediated transcriptional suppression of Txnip is critical for pancreatic beta cell function and survival in mice.

PubMed

Qin, Kunhua; Zhang, Ning; Zhang, Zhao; Nipper, Michael; Zhu, Zhenxin; Leighton, Jake; Xu, Kexin; Musi, Nicolas; Wang, Pei

2018-04-01

Better understanding of how genetic and epigenetic components control beta cell differentiation and function is key to the discovery of novel therapeutic approaches to prevent beta cell dysfunction and failure in the progression of type 2 diabetes. Our goal was to elucidate the role of histone deacetylase sirtuin 6 (SIRT6) in beta cell development and homeostasis. Sirt6 endocrine progenitor cell conditional knockout and beta cell-specific knockout mice were generated using the Cre-loxP system. Mice were assayed for islet morphology, glucose tolerance, glucose-stimulated insulin secretion and susceptibility to streptozotocin. Transcriptional regulatory functions of SIRT6 in primary islets were evaluated by RNA-Seq analysis. Reverse transcription-quantitative (RT-q)PCR and immunoblot were used to verify and investigate the gene expression changes. Chromatin occupancies of SIRT6, H3K9Ac, H3K56Ac and active RNA polymerase II were evaluated by chromatin immunoprecipitation. Deletion of Sirt6 in pancreatic endocrine progenitor cells did not affect endocrine morphology, beta cell mass or insulin production but did result in glucose intolerance and defective glucose-stimulated insulin secretion in mice. Conditional deletion of Sirt6 in adult beta cells reproduced the insulin secretion defect. Loss of Sirt6 resulted in aberrant upregulation of thioredoxin-interacting protein (TXNIP) in beta cells. SIRT6 deficiency led to increased acetylation of histone H3 lysine residue at 9 (H3K9Ac), acetylation of histone H3 lysine residue at 56 (H3K56Ac) and active RNA polymerase II at the promoter region of Txnip. SIRT6-deficient beta cells exhibited a time-dependent increase in H3K9Ac, H3K56Ac and TXNIP levels. Finally, beta cell-specific SIRT6-deficient mice showed increased sensitivity to streptozotocin. Our results reveal that SIRT6 suppresses Txnip expression in beta cells via deacetylation of histone H3 and plays a critical role in maintaining beta cell function and viability. Sequence data have been deposited in the National Institutes of Health (NIH) Gene Expression Omnibus (GEO) with the accession code GSE104161.

On the role of transforming growth factor-beta in the growth inhibitory effects of retinoic acid in human pancreatic cancer cells.

PubMed

Singh, Brahmchetna; Murphy, Richard F; Ding, Xian-Zhong; Roginsky, Alexandra B; Bell, Richard H; Adrian, Thomas E

2007-12-24

Retinoids are potent growth inhibitory and differentiating agents in a variety of cancer cell types. We have shown that retinoids induce growth arrest in all pancreatic cancer cell lines studied, regardless of their p53 and differentiation status. However, the mechanism of growth inhibition is not known. Since TGF-beta2 is markedly induced by retinoids in other cancers and mediates MUC4 expression in pancreatic cancer cells, we investigated the role of TGF-beta in retinoic acid-mediated growth inhibition in pancreatic cancer cells. Retinoic acid markedly inhibited proliferation of two cell lines (Capan-2 and Hs766T) in a concentration and time-dependent manner. Retinoic acid increased TGF-beta2 mRNA content and secretion of the active and latent forms of TGF-beta2 (measured by ELISA and bioassay). The concentrations of active and TGF-beta2 secreted in response to 0.1 - 10 muM retinoic acid were between 1-5 pM. TGF-beta2 concentrations within this range also inhibited proliferation. A TGF-beta neutralizing antibody blocked the growth inhibitory effects of retinoic acid in Capan-2 cells and partially inhibitory the effects in Hs766T cells. These findings indicate that TGF-beta can cause growth inhibition of pancreatic cancer cells, in a p53-independent manner. Furthermore, it demonstrates the fundamental role of TGF-beta in growth inhibition in response to retinoic acid treatment is preserved in vitro.

Differential usage of T-cell receptor V beta gene families by CD4+ and CD8+ T cells in patients with CD8hi common variable immunodeficiency: evidence of a post-thymic effect.

PubMed Central

Duchmann, R; Jaffe, J; Ehrhardt, R; Alling, D W; Strober, W

1996-01-01

In this study, we report that differences between T-cell receptor (TCR) V beta gene family usage in CD4+ and CD8+ T cells are significantly greater in a subgroup of patients with common variable immunodeficiency (CVI) and high levels of activated CD8+ T cells (CD8hi CVI) than in controls (P < 0.001). In CD8hi CVI patients, such differences were also significantly greater for V beta 12 than for other V beta families. As the causes of the differential usage of V beta gene families by CD4+ and CD8+ T cells are under investigation, it was interesting that the combined differences between V beta gene family usage in the CD4+ and CD8+ T-cell subpopulations as a whole were significantly lower than the combined differences between individual V beta gene family usage in either CD4+ or CD8+ T-cell subpopulations (P < 0.001 in both control and CD8hi CVI patients). Further, the pattern of V beta gene family usage in CD4+ T cells was remarkably similar to that in CD8+ T cells in both groups. These data strongly suggest that differences in V beta gene family usage arising from coselection by major histocompatibility complex (MHC) class I versus MHC class II restriction elements do not fundamentally distort 'basic' V beta gene family usage patterns. They also support the concept that differences in CD4+ and CD8+ T-cell V beta gene family usage, which were increased in CD8hi CVI, can arise from high-affinity interactions between disease-associated antigens or superantigens and T cells in the post-thymic T-cell compartment. Images Figure 6 PMID:8666443

A recombinant tail-less integrin beta 4 subunit disrupts hemidesmosomes, but does not suppress alpha 6 beta 4-mediated cell adhesion to laminins

PubMed Central

1995-01-01

To examine the function of the alpha 6 beta 4 integrin we have determined its ligand-binding ability and overexpressed two potentially dominant negative mutant beta 4 subunits, lacking either the cytoplasmic or extracellular domain, in bladder epithelial 804G cells. The results of cell adhesion and radioligand-binding assays showed that alpha 6 beta 4 is a receptor for several laminin isoforms, including laminin 1, 2, 4, and 5. Overexpression of the tail-less or head-less mutant beta 4 subunit did not suppress alpha 6 beta 4-mediated adhesion to laminins, as both types of transfectants adhered to these ligands in the presence of blocking anti-beta 1 antibodies as well as the controls. However, immunofluorescence experiments indicated that the endogenous alpha 6 beta 4 integrin and other hemidesmosomal markers were not concentrated in hemidesmosomes in cells overexpressing tail- less beta 4, while the distribution of these molecules was not altered in cells overexpressing the head-less subunit. Electron microscopic studies confirmed that cells overexpressing tail-less beta 4 had a drastically reduced number of hemidesmosomes, while cells expressing the head-less subunit had a normal number of these structures. Thus, expression of a tail-less, but not a head-less mutant beta 4 subunit leads to a dominant negative effect on hemidesmosome assembly without suppressing initial adhesion to laminins. We conclude that the alpha 6 beta 4 integrin binds to several laminins and plays an essential role in the assembly and/or stability of hemidesmosomes, that alpha 6 beta 4- mediated adhesion and hemidesmosome assembly have distinct requirements, and that it is possible to use a dominant negative approach to selectively interfere with a specific function of an integrin. PMID:7721947

DOE Office of Scientific and Technical Information (OSTI.GOV)

K Kucera; A Koblansky; L Saunders

Profilins promote actin polymerization by exchanging ADP for ATP on monomeric actin and delivering ATP-actin to growing filament barbed ends. Apicomplexan protozoa such as Toxoplasma gondii invade host cells using an actin-dependent gliding motility. Toll-like receptor (TLR) 11 generates an innate immune response upon sensing T. gondii profilin (TgPRF). The crystal structure of TgPRF reveals a parasite-specific surface motif consisting of an acidic loop, followed by a long {beta}-hairpin. A series of structure-based profilin mutants show that TLR11 recognition of the acidic loop is responsible for most of the interleukin (IL)-12 secretion response to TgPRF in peritoneal macrophages. Deletion ofmore » both the acidic loop and the {beta}-hairpin completely abrogates IL-12 secretion. Insertion of the T. gondii acidic loop and {beta}-hairpin into yeast profilin is sufficient to generate TLR11-dependent signaling. Substitution of the acidic loop in TgPRF with the homologous loop from the apicomplexan parasite Cryptosporidium parvum does not affect TLR11-dependent IL-12 secretion, while substitution with the acidic loop from Plasmodium falciparum results in reduced but significant IL-12 secretion. We conclude that the parasite-specific motif in TgPRF is the key molecular pattern recognized by TLR11. Unlike other profilins, TgPRF slows nucleotide exchange on monomeric rabbit actin and binds rabbit actin weakly. The putative TgPRF actin-binding surface includes the {beta}-hairpin and diverges widely from the actin-binding surfaces of vertebrate profilins.« less

Gene Editing and Human Pluripotent Stem Cells: Tools for Advancing Diabetes Disease Modeling and Beta-Cell Development.

PubMed

Millette, Katelyn; Georgia, Senta

2017-10-05

This review will focus on the multiple approaches to gene editing and address the potential use of genetically modified human pluripotent stem cell-derived beta cells (SC-β) as a tool to study human beta-cell development and model their function in diabetes. We will explore how new variations of CRISPR/Cas9 gene editing may accelerate our understanding of beta-cell developmental biology, elucidate novel mechanisms that establish and regulate beta-cell function, and assist in pioneering new therapeutic modalities for treating diabetes. Improvements in CRISPR/Cas9 target specificity and homology-directed recombination continue to advance its use in engineering stem cells to model and potentially treat disease. We will review how CRISPR/Cas9 gene editing is informing our understanding of beta-cell development and expanding the therapeutic possibilities for treating diabetes and other diseases. Here we focus on the emerging use of gene editing technology, specifically CRISPR/Cas9, as a means of manipulating human gene expression to gain novel insights into the roles of key factors in beta-cell development and function. Taken together, the combined use of SC-β cells and CRISPR/Cas9 gene editing will shed new light on human beta-cell development and function and accelerate our progress towards developing new therapies for patients with diabetes.

The glucagon-like peptide-2 receptor C terminus modulates beta-arrestin-2 association but is dispensable for ligand-induced desensitization, endocytosis, and G-protein-dependent effector activation.

PubMed

Estall, Jennifer L; Koehler, Jacqueline A; Yusta, Bernardo; Drucker, Daniel J

2005-06-10

Classic models of receptor desensitization and internalization have been largely based on the behavior of Family A G-protein-coupled receptors (GPCRs). The glucagon-like peptide-2 receptor (GLP-2R) is a member of the Family B glucagon-secretin GPCR family, which exhibit significant sequence and structural differences from the Family A receptors in their intracellular and extracellular domains. To identify structural motifs that regulate GLP-2R signaling and cell surface receptor expression, we analyzed the functional properties of a series of mutant GLP-2Rs. The majority of the C-terminal receptor tail was dispensable for GLP-2-induced cAMP accumulation, ERK1/2 activation, and endocytosis in transfected cells. However, progressive truncation of the C terminus reduced cell surface receptor expression, altered agonist-induced GLP-2R trafficking, and abrogated protein kinase A-mediated heterologous receptor desensitization. Elimination of the distal 21 amino acids of the receptor was sufficient to promote constitutive receptor internalization and prevent agonist-induced recruitment of beta-arrestin-2. Site-directed mutagenesis identified specific amino acid residues within the distal GLP-2R C terminus that mediate the stable association with beta-arrestin-2. Surprisingly, although the truncated mutant receptors failed to interact with beta-arrestin-2, they underwent homologous desensitization and subsequent resensitization with kinetics similar to that observed with the wild-type GLP-2R. Our data suggest that, although the GLP-2R C terminus is not required for coupling to cellular machinery regulating signaling or desensitization, it may serve as a sorting signal for intracellular trafficking. Taken together with the previously demonstrated clathrin and dynamin-independent, lipid-raft-dependent pathways for internalization, our data suggest that GLP-2 receptor signaling has evolved unique structural and functional mechanisms for control of receptor trafficking, desensitization, and resensitization.

Cell-to-cell contact dependence and junctional protein content are correlated with in vivo maturation of pancreatic beta cells.

PubMed

Santos-Silva, Junia Carolina; Carvalho, Carolina Prado de França; de Oliveira, Ricardo Beltrame; Boschero, Antonio Carlos; Collares-Buzato, Carla Beatriz

2012-07-01

In this study, we investigated the cellular distribution of junctional proteins and the dependence on cell-cell contacts of pancreatic beta cells during animal development. Fetus and newborn rat islets, which display a relatively poor insulin secretory response to glucose, present an immature morphology and cytoarchitecture when compared with young and adult islets that are responsive to glucose. At the perinatal stage, beta cells display a low junctional content of neural cell adhesion molecule (N-CAM), α- and β-catenins, ZO-1, and F-actin, while a differential distribution of N-CAM and Pan-cadherin was seen in beta cells and nonbeta cells only from young and adult islets. In the absence of intercellular contacts, the glucose-stimulated insulin secretion was completely blocked in adult beta cells, but after reaggregation they partially reestablished the secretory response to glucose. By contrast, neonatal beta cells were poorly responsive to sugar, regardless of whether they were arranged as intact islets or as isolated cells. Interestingly, after 10 days of culturing, neonatal beta cells, known to display increased junctional protein content in vitro, became responsive to glucose and concomitantly dependent on cell-cell contacts. Therefore, our data suggest that the developmental acquisition of an adult-like insulin secretory pattern is paralleled by a dependence on direct cell-cell interactions.

Islet immunity and beta cell reserve of indigenous Black South Africans with ketoacidosis at initial diagnosis of diabetes.

PubMed

Ekpebegh, Chukwuma; Longo-Mbenza, Benjamin; Blanco-Blanco, Ernesto

2013-01-01

Islet immunity and beta cell reserve status were utilized to classify persons with ketoacidosis as the initial manifestation of diabetes. The clinical features of the various diabetes classes were also characterized. Prospective cross sectional study. Nelson Mandela Academic Hospital, Mthatha, Eastern Cape Province, South Africa. Indigenous Black South Africans with ketoacidosis as the initial manifestation of diabetes. Islet immunity and beta cell reserve were respectively assessed using serum anti-glutamic acid decarboxylase 65 (GAD) antibody and serum C-peptide after 1 mg of intravenous glucagon. Serum anti-GAD 65 antibody > or = 5 units/L and < 5 units/L, respectively defined anti-GAD 65 positive (A+) and negative (A-). Replete (beta+) and deplete (beta-) beta cell reserve were serum C-peptide after glucagon injection of > or = 0.5 ng/mL and < 0.5 ng/mL, respectively. The proportions of patients with A+beta-, A+beta+, A-beta- and A-beta+ and their clinical characteristics were determined. Of the 38 males and 33 females who participated in the study, patients were categorized in various classes: A-beta+, 46.5% (n=33/ 71); A-beta-, 26.8% (n=19/71); A+beta-, 22.5% (n=16/71); and A+beta+, 4.2% (n=3/71). The ages of the various classes were: 41.8 +/- 13.8 years for A-beta+ (n=33); 36.5 +/- 14.6 years for A-beta- (n=19); and 20.6 +/- 7.1 years for the combination of A+beta- with A+beta+ (n=19) (P<.0001, P<.0001 for the combination of A+beta- and A+beta+ vs A-beta+, P=.001 for the combination of A+beta- and A+beta+ vs A-beta-and P=.2 for A-beta- vs A-beta+. The clinical features of type 2 diabetes were most prevalent in A-beta+ class while the A+beta- and A+beta+ groups had the clinical profile of type 1A diabetes. Most of the indigenous Black South African patients with ketoacidosis as the initial manifestation of diabetes had islet immunity, beta cell reserve status and clinical profiles of type 2 diabetes.

Intermittent fasting preserves beta-cell mass in obesity-induced diabetes via the autophagy-lysosome pathway.

PubMed

Liu, Haiyan; Javaheri, Ali; Godar, Rebecca J; Murphy, John; Ma, Xiucui; Rohatgi, Nidhi; Mahadevan, Jana; Hyrc, Krzysztof; Saftig, Paul; Marshall, Connie; McDaniel, Michael L; Remedi, Maria S; Razani, Babak; Urano, Fumihiko; Diwan, Abhinav

2017-01-01

Obesity-induced diabetes is characterized by hyperglycemia, insulin resistance, and progressive beta cell failure. In islets of mice with obesity-induced diabetes, we observe increased beta cell death and impaired autophagic flux. We hypothesized that intermittent fasting, a clinically sustainable therapeutic strategy, stimulates autophagic flux to ameliorate obesity-induced diabetes. Our data show that despite continued high-fat intake, intermittent fasting restores autophagic flux in islets and improves glucose tolerance by enhancing glucose-stimulated insulin secretion, beta cell survival, and nuclear expression of NEUROG3, a marker of pancreatic regeneration. In contrast, intermittent fasting does not rescue beta-cell death or induce NEUROG3 expression in obese mice with lysosomal dysfunction secondary to deficiency of the lysosomal membrane protein, LAMP2 or haplo-insufficiency of BECN1/Beclin 1, a protein critical for autophagosome formation. Moreover, intermittent fasting is sufficient to provoke beta cell death in nonobese lamp2 null mice, attesting to a critical role for lysosome function in beta cell homeostasis under fasting conditions. Beta cells in intermittently-fasted LAMP2- or BECN1-deficient mice exhibit markers of autophagic failure with accumulation of damaged mitochondria and upregulation of oxidative stress. Thus, intermittent fasting preserves organelle quality via the autophagy-lysosome pathway to enhance beta cell survival and stimulates markers of regeneration in obesity-induced diabetes.

Molecular role of TGF-beta, secreted from a new type of CD4+ suppressor T cell, NY4.2, in the prevention of autoimmune IDDM in NOD mice.

PubMed

Han, H S; Jun, H S; Utsugi, T; Yoon, J W

1997-06-01

A new type of CD4+ T cell clone (NY4.2) isolated from pancreatic islet-infiltrated lymphocytes of acutely diabetic non-obese diabetic (NOD) mice prevents the development of insulin-dependent diabetes mellitus (IDDM) in NOD mice, as well as the recurrence of autoimmune diabetes in syngeneic islet-transplanted NOD mice. It has been demonstrated that the cytokine TGF-beta, secreted from the cells of this clone, is the substance which prevents autoimmune IDDM. This investigation was initiated to determine the molecular role TGF-beta plays in the prevention of autoimmune IDDM by determining its effect on IL-2-induced signal transduction in Con A-activated NOD mouse splenocytes and HT-2 cells. First, we determined whether TGF-beta, secreted from NY4.2 T cells, inhibits IL-2-dependent T cell proliferation in HT-2 cells (IL-2-dependent T cell line) and NOD splenocytes. We found that TGF-beta suppresses IL-2-dependent T cell proliferation. Second, we determined whether TGF-beta inhibits the activation of Janus kinases (JAKs), as well as signal transducers and activators of transcription (STAT) proteins, involved in an IL-2-induced signalling pathway that normally leads to the proliferation of T cells. We found that TGF-beta inhibited tyrosine phosphorylation of JAK1, JAK3, STAT3 and STAT5 in Con A blasts from NOD splenocytes and HT-2 cells. Third, we examined whether TGF-beta inhibits the cooperation between STAT proteins and mitogen-activated protein kinase (MAPK), especially extracellular signal-regulated kinase 2 (ERK2). We found that TGF-beta inhibited the association of STAT3 and STAT5 with ERK2 in Con A blasts from NOD splenocytes and HT-2 cells. On the basis of these observations, we conclude that TGF-beta may interfere with signal transduction via inhibition of the IL-2-induced JAK/STAT pathway and inhibition of the association of STAT proteins with ERK2 in T cells from NOD splenocytes, resulting in the inhibition of IL-2-dependent T cell proliferation. TGF-beta-mediated suppression of T cell activation may be responsible for the prevention of effector T cell-mediated autoimmune IDDM in NOD mice by TGF-beta-producing CD4+ suppressor T cells.

Hypothyroidism in utero stimulates pancreatic beta cell proliferation and hyperinsulinaemia in the ovine fetus during late gestation.

PubMed

Harris, Shelley E; De Blasio, Miles J; Davis, Melissa A; Kelly, Amy C; Davenport, Hailey M; Wooding, F B Peter; Blache, Dominique; Meredith, David; Anderson, Miranda; Fowden, Abigail L; Limesand, Sean W; Forhead, Alison J

2017-06-01

Thyroid hormones are important regulators of growth and maturation before birth, although the extent to which their actions are mediated by insulin and the development of pancreatic beta cell mass is unknown. Hypothyroidism in fetal sheep induced by removal of the thyroid gland caused asymmetric organ growth, increased pancreatic beta cell mass and proliferation, and was associated with increased circulating concentrations of insulin and leptin. In isolated fetal sheep islets studied in vitro, thyroid hormones inhibited beta cell proliferation in a dose-dependent manner, while high concentrations of insulin and leptin stimulated proliferation. The developing pancreatic beta cell is therefore sensitive to thyroid hormone, insulin and leptin before birth, with possible consequences for pancreatic function in fetal and later life. The findings of this study highlight the importance of thyroid hormones during pregnancy for normal development of the fetal pancreas. Development of pancreatic beta cell mass before birth is essential for normal growth of the fetus and for long-term control of carbohydrate metabolism in postnatal life. Thyroid hormones are also important regulators of fetal growth, and the present study tested the hypotheses that thyroid hormones promote beta cell proliferation in the fetal ovine pancreatic islets, and that growth retardation in hypothyroid fetal sheep is associated with reductions in pancreatic beta cell mass and circulating insulin concentration in utero. Organ growth and pancreatic islet cell proliferation and mass were examined in sheep fetuses following removal of the thyroid gland in utero. The effects of triiodothyronine (T 3 ), insulin and leptin on beta cell proliferation rates were determined in isolated fetal ovine pancreatic islets in vitro. Hypothyroidism in the sheep fetus resulted in an asymmetric pattern of organ growth, pancreatic beta cell hyperplasia, and elevated plasma insulin and leptin concentrations. In pancreatic islets isolated from intact fetal sheep, beta cell proliferation in vitro was reduced by T 3 in a dose-dependent manner and increased by insulin at high concentrations only. Leptin induced a bimodal response whereby beta cell proliferation was suppressed at the lowest, and increased at the highest, concentrations. Therefore, proliferation of beta cells isolated from the ovine fetal pancreas is sensitive to physiological concentrations of T 3 , insulin and leptin. Alterations in these hormones may be responsible for the increased beta cell proliferation and mass observed in the hypothyroid sheep fetus and may have consequences for pancreatic function in later life. © 2017 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.

Role of estrogen receptors alpha, beta and GPER1/GPR30 in pancreatic beta-cells.

PubMed

Nadal, Angel; Alonso-Magdalena, Paloma; Soriano, Sergi; Ripoll, Cristina; Fuentes, Esther; Quesada, Ivan; Ropero, Ana Belen

2011-01-01

Estrogen receptors (ER) are emerging as important molecules involved in the adaptation of beta-cells to insulin resistance. The onset of type 2 diabetes is marked by insulin secretory dysfunction and decreased beta-cell mass. During pregnancy, puberty and obesity there is increased metabolic demand and insulin resistance is developed. This metabolic state increases the demand on beta-cells to augment insulin biosynthesis and release. In this respect, ERalpha is directly implicated in the E2-regulation of insulin content and secretion, while ERbeta is in the E2-potentiation of glucose-induced insulin release. Both receptors develop their actions within the physiological range of E2. In addition, the G protein-coupled estrogen receptor (GPER1/GPR30) seems to be implicated in the E2-regulation of stimulus-secretion coupling in the three cell types of the islet. The increased demand of insulin production for long time may lead to beta-cell stress and apoptosis. ERalpha, ERbeta and GPER1/GPR30 are involved in preventing beta-cell apoptosis, impeding the loss of critical beta-cell mass. Therefore, estrogen receptors may play an essential role in the adaptation of the pancreas to insulin resistant periods.

Interleukin-1{beta} regulates cell proliferation and activity of extracellular matrix remodelling enzymes in cultured primary pig heart cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zitta, Karina; Brandt, Berenice; Wuensch, Annegret

Research highlights: {yields} Levels of IL-1{beta} are increased in the pig myocardium after infarction. {yields} Cultured pig heart cells possess IL-1 receptors. {yields} IL-1{beta} increases cell proliferation of pig heart cells in-vitro. {yields} IL-1{beta} increases MMP-2 and MMP-9 activity in pig heart cells in-vitro. {yields} IL-1{beta} may be important for tissue remodelling events after myocardial infarction. -- Abstract: After myocardial infarction, elevated levels of interleukins (ILs) are found within the myocardial tissue and IL-1{beta} is considered to play a major role in tissue remodelling events throughout the body. In the study presented, we have established a cell culture model ofmore » primary pig heart cells to evaluate the effects of different concentrations of IL-1{beta} on cell proliferation as well as expression and activity of enzymes typically involved in tissue remodelling. Primary pig heart cell cultures were derived from three different animals and stimulated with recombinant pig IL-1{beta}. RNA expression was detected by RT-PCR, protein levels were evaluated by Western blotting, activity of matrix metalloproteinases (MMPs) was quantified by gelatine zymography and cell proliferation was measured using colorimetric MTS assays. Pig heart cells express receptors for IL-1 and application of IL-1{beta} resulted in a dose-dependent increase of cell proliferation (P < 0.05 vs. control; 100 ng/ml; 24 h). Gene expression of caspase-3 was increased by IL-1{beta} (P < 0.05 vs. control; 100 ng/ml; 3 h), and pro-caspase-3 but not active caspase was detected in lysates of pig heart cells by Western blotting. MMP-2 gene expression as well as enzymatic activities of MMP-2 and MMP-9 were increased by IL-1{beta} (P < 0.05 vs. control; 100 ng/ml; 3 h for gene expression, 48 and 72 h for enzymatic activities of MMP-2 and MMP-9, respectively). Our in vitro data suggest that IL-1{beta} plays a major role in the events of tissue remodelling in the heart. Combined with our recently published in vivo data (Meybohm et al., PLoS One, 2009), the results presented here strongly suggest IL-1{beta} as a key molecule guiding tissue remodelling events after myocardial infarction.« less

Characterization of rat leydig cell gonadotropin receptor structure by affinity cross-linking

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Q.Y.; Hwang, J.; Menon, K.M.J.

1986-05-01

The gonadotropin receptor from rat leydig cell has been characterized with respect to binding kinetics and physiological regulation. The present study was intended to examine the structure of the receptor. Leydig cell suspension was prepared by either collagenase digestion or by mechanical disruption of the testis. The cells were incubated with /sup 125/I-hCG and the unreacted hCG was removed by centrifugation. The /sup 125/I-hCG was then covalently linked to the cell surface receptor using cleavable (dithiobis (succinimidyl propionate)) and non-cleavable (disuccinimidyl suberate) cross-linking reagents. The extracted cross-linked membrane proteins were resolved on SDS-polyacrylamide gels under reducing and non-reducing conditions andmore » subjected to autoradiographic analysis. Under non-reducing conditions, two labeled species with M/sub r/ = 87,000 and 120,000 were detected. However, only one labeled band was detected under reducing conditions with M/sub r/ = 64,000. The binding of /sup 125/I-hCG to the receptor was inhibited by hCG and LH, but not by a number of peptides and proteins. The data suggest that hCG receptor in leydig cell is an oligomeric complex consisting of four subunits, ..cap alpha cap alpha beta gamma... The ..beta.. and ..gamma.. subunits are each linked to an ..cap alpha.. subunit through disulfide linkage and the hormone binds to each ..cap alpha.. subunit. The two dimers formed (..cap alpha beta cap alpha gamma..) are associated by noncovalent interactions.« less

Identification of beta-2 as a key cell adhesion molecule in PCa cell neurotropic behavior: a novel ex vivo and biophysical approach.

PubMed

Jansson, Keith H; Castillo, Deborah G; Morris, Joseph W; Boggs, Mary E; Czymmek, Kirk J; Adams, Elizabeth L; Schramm, Lawrence P; Sikes, Robert A

2014-01-01

Prostate cancer (PCa) is believed to metastasize through the blood/lymphatics systems; however, PCa may utilize the extensive innervation of the prostate for glandular egress. The interaction of PCa and its nerve fibers is observed in 80% of PCa and is termed perineural invasion (PNI). PCa cells have been observed traveling through the endoneurium of nerves, although the underlying mechanisms have not been elucidated. Voltage sensitive sodium channels (VSSC) are multimeric transmembrane protein complexes comprised of a pore-forming α subunit and one or two auxiliary beta (β) subunits with inherent cell adhesion molecule (CAM) functions. The beta-2 isoform (gene SCN2B) interacts with several neural CAMs, while interacting putatively with other prominent neural CAMs. Furthermore, beta-2 exhibits elevated mRNA and protein levels in highly metastatic and castrate-resistant PCa. When overexpressed in weakly aggressive LNCaP cells (2BECFP), beta-2 alters LNCaP cell morphology and enhances LNCaP cell metastasis associated behavior in vitro. We hypothesize that PCa cells use beta-2 as a CAM during PNI and subsequent PCa metastasis. The objective of this study was to determine the effect of beta-2 expression on PCa cell neurotropic metastasis associated behavior. We overexpressed beta-2 as a fusion protein with enhanced cyan fluorescence protein (ECFP) in weakly aggressive LNCaP cells and observed neurotropic effects utilizing our novel ex vivo organotypic spinal cord co-culture model, and performed functional assays with neural matrices and atomic force microscopy. With increased beta-2 expression, PCa cells display a trend of enhanced association with nerve axons. On laminin, a neural CAM, overexpression of beta-2 enhances PCa cell migration, invasion, and growth. 2BECFP cells exhibit marked binding affinity to laminin relative to LNECFP controls, and recombinant beta-2 ectodomain elicits more binding events to laminin than BSA control. Functional overexpression of VSSC beta subunits in PCa may mediate PCa metastatic behavior through association with neural matrices.

Transforming growth factor-{beta} inhibits CCAAT/enhancer-binding protein expression and PPAR{gamma} activity in unloaded bone marrow stromal cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahdjoudj, S.; Kaabeche, K.; Holy, X.

2005-02-01

The molecular mechanisms regulating the adipogenic differentiation of bone marrow stromal cells in vivo remain largely unknown. In this study, we investigated the regulatory effects of transforming growth factor beta-2 (TGF-{beta}2) on transcription factors involved in adipogenic differentiation induced by hind limb suspension in rat bone marrow stromal cells in vivo. Time course real-time quantitative reverse-transcription polymerase chain reaction (RT-PCR) analysis of gene expression showed that skeletal unloading progressively increases the expression of CCAAT/enhancer-binding protein (C/EBP){alpha} and C/EBP{beta} {alpha} at 5 days in bone marrow stromal cells resulting in increased peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}2) transcripts at 7 days. TGF-{beta}2more » administration in unloaded rats corrected the rise in C/EBP{alpha} and C/EBP{beta} transcripts induced by unloading in bone marrow stromal cells. This resulted in inhibition of PPAR{gamma}2 expression that was associated with increased Runx2 expression. Additionally, the inhibition of C/EBP{alpha} and C/EBP{beta} expression by TGF-{beta}2 was associated with increased PPAR{gamma} serine phosphorylation in bone marrow stromal cells, a mechanism that inhibits PPAR{gamma} transactivating activity. The sequential inhibitory effect of TGF-{beta}2 on C/EBP{alpha}, C/EBP{beta}, and PPAR{gamma}2 resulted in reduced LPL expression and abolition of bone marrow stromal cell adipogenic differentiation, which contributed to prevent bone loss induced by skeletal unloading. We conclude that TGF-{beta}2 inhibits the excessive adipogenic differentiation of bone marrow stromal cells induced by skeletal unloading by inhibiting C/EBP{alpha}, C/EBP{beta}, and PPAR{gamma} expression and activity, which provides a sequential mechanism by which TGF-{beta}2 regulates adipogenic differentiation of bone marrow stromal cells in vivo.« less

Exposure of T lymphocytes to leflunomide but not to dexamethasone favors the production by monocytic cells of interleukin-1 receptor antagonist and the tissue-inhibitor of metalloproteinases-1 over that of interleukin-1beta and metalloproteinases.

PubMed

Déage, V; Burger, D; Dayer, J M

1998-12-01

On direct cell-cell contact, stimulated T lymphocytes potently trigger the production of pro-inflammatory factors such as interleukin-1beta (IL-1beta) and matrix metalloproteinases (MMP-1 and MMP-9), as well as anti-inflammatory factors such as IL-1 receptor antagonist (IL-1Ra) and the tissue inhibitor of metalloproteinases (TIMP-1) in peripheral blood monocytes and the monocytic cell line THP-1. Such mechanisms might play an important part in many inflammatory diseases where tissue destruction occurs. To assess whether anti-inflammatory agents such as dexamethasone (DEX) and leflunomide (LF) would affect contact-activation of monocytic cells, T lymphocytes were stimulated by PMA and PHA in the presence or absence of increasing concentrations of drug. LF and DEX (10- 4 M) inhibited the ability of stimulated T lymphocytes to activate monocytic cells by 66-97% and 43-70%, respectively, depending on the readout product. Upon contact with T lymphocytes stimulated in the presence of 10- 5 M LF, the molar ratio of IL-1Ra/IL-1beta and TIMP-1/MMP-1 produced by THP-1 cells was enhanced 3.6- and 1.9-fold, respectively, whereas it was enhanced only 1.3- and 1.4-fold upon contact with T lymphocytes stimulated in the presence of 10- 4 M DEX. Therefore, LF tends to favor the inhibition of pro-inflammatory and matrix-destructive factors over that of anti-inflammatory factors and metalloproteinase inhibitors, thus interfering with both inflammation and tissue destruction. These experiments indicate that LF and DEX have the potential to affect the capacity of stimulated T lymphocytes to activate, on direct cell-cell contact, monocytic cells. Furthermore, flow cytometric analysis revealed that surface molecules of T lymphocytes that were partially involved in contact-signaling of monocytes (i.e., CD69 and CD11) were not modulated by either LF or DEX, suggesting that factors which remain to be identified were mainly involved in the activation of monocytes on direct cell-cell contact.

A novel mechanism of vascular endothelial growth factor, leptin and transforming growth factor-beta2 sequestration in a subpopulation of human ovarian follicle cells.

PubMed

Antczak, M; Van Blerkom, J; Clark, A

1997-10-01

This study describes the occurrence of a highly specialized subpopulation of granulosa and cumulus oophorus cells that accumulate and sequester specific growth factors by a novel mechanism. These cells are characterized by multiple balloon-like processes tethered to the cell by means of a slender stalk of plasma membrane. Time-lapse analyses demonstrate that these tethered structures (TS) form in minutes and frequently detach from the cell with the bulbous portion remaining motile on the cell surface. Serial section reconstruction of transmission electron microscopic images shows a specific and stable intracellular organization in which an apparent secretory compartment composed of densely packed vacuoles, vesicles, and cisternae is separated by a thick filamentous network from a nuclear compartment containing mitochondria, polyribosomes, lipid inclusions, and rough-surfaced endoplasmic reticulum. Immunofluorescent analysis performed during the formation of these structures showed a progressive accumulation of vascular endothelial growth factor, leptin, and transforming growth factor-beta2 in the bulbous region. TS were identified in newly aspirated masses of granulosa and cumulus oophorus, and their production persists for months in culture. Observations of TS-forming cells made over several days of culture indicates that their production is episodic and factor release from these cells may be pulsatile. The findings suggest that a novel method of growth factor storage and release by an apparent apocrine-like mechanism occurs in the human ovarian follicle. The results are discussed with respect to possible roles in pre- and post-ovulatory follicular development.

Transforming growth factor-beta1 transcriptionally activates CD34 and prevents induced differentiation of TF-1 cells in the absence of any cell-cycle effects.

PubMed

Marone, M; Scambia, G; Bonanno, G; Rutella, S; de Ritis, D; Guidi, F; Leone, G; Pierelli, L

2002-01-01

A number of cytokines modulate self-renewal and differentiation of hematopoietic elements. Among these is transforming growth factor beta1 (TGF-beta1), which regulates cell cycle and differentiation of hematopoietic cells, but has pleiotropic activities depending on the state of responsiveness of the target cells. It has been previously shown by us and other authors that TGF-beta1 maintains human CD34(+) hematopoietic progenitors in an undifferentiated state, independently of any cell cycle effects, and that depletion of TGF-beta1 triggers differentiation accompanied by a decrease in CD34 antigen expression. In the present work, we show that exogenous TGF-beta1 upregulates the human CD34 antigen in the CD34(+) cell lines TF-1 and KG-1a, but not in the more differentiated CD34(-) cell lines HL-60 and K-562. We further studied this effect in the pluripotent erythroleukemia cell line TF-1. Here, TGF-beta1 did not effect cell growth, but induced transcriptional activation of full-length CD34 and prevented differentiation induced by differentiating agents. This effect was associated with nuclear translocation of Smad-2, activation of TAK-1, and with a dramatic decrease in p38 phosphorylation. In other systems TGF-beta1 has been shown to activate a TGF-beta-activated kinase 1 (TAK1), which in turn, activates p38. The specific inhibitor of p38 phosphorylation, SB202190, also increased CD34 RNA expression, indicating the existence of a link between p-38 inhibition by TGF-beta1 and CD34 overexpression. Our data demonstrate that TGF-beta1 transcriptionally activates CD34 and prevents differentiation of TF-1 cells by acting independently through the Smad, TAK1 and p38 pathways, and thus provide important clues for the understanding of hematopoietic development and a potential tool to modify response of hematopoietic cells to mitogens or differentiating agents.

Orphan nuclear receptor TLX activates Wnt/beta-catenin signalling to stimulate neural stem cell proliferation and self-renewal.

PubMed

Qu, Qiuhao; Sun, Guoqiang; Li, Wenwu; Yang, Su; Ye, Peng; Zhao, Chunnian; Yu, Ruth T; Gage, Fred H; Evans, Ronald M; Shi, Yanhong

2010-01-01

The nuclear receptor TLX (also known as NR2E1) is essential for adult neural stem cell self-renewal; however, the molecular mechanisms involved remain elusive. Here we show that TLX activates the canonical Wnt/beta-catenin pathway in adult mouse neural stem cells. Furthermore, we demonstrate that Wnt/beta-catenin signalling is important in the proliferation and self-renewal of adult neural stem cells in the presence of epidermal growth factor and fibroblast growth factor. Wnt7a and active beta-catenin promote neural stem cell self-renewal, whereas the deletion of Wnt7a or the lentiviral transduction of axin, a beta-catenin inhibitor, led to decreased cell proliferation in adult neurogenic areas. Lentiviral transduction of active beta-catenin led to increased numbers of type B neural stem cells in the subventricular zone of adult brains, whereas deletion of Wnt7a or TLX resulted in decreased numbers of neural stem cells retaining bromodeoxyuridine label in the adult brain. Both Wnt7a and active beta-catenin significantly rescued a TLX (also known as Nr2e1) short interfering RNA-induced deficiency in neural stem cell proliferation. Lentiviral transduction of an active beta-catenin increased cell proliferation in neurogenic areas of TLX-null adult brains markedly. These results strongly support the hypothesis that TLX acts through the Wnt/beta-catenin pathway to regulate neural stem cell proliferation and self-renewal. Moreover, this study suggests that neural stem cells can promote their own self-renewal by secreting signalling molecules that act in an autocrine/paracrine mode.

Sitagliptin inhibit human lymphocytes proliferation and Th1/Th17 differentiation in vitro.

PubMed

Pinheiro, Marcelo Maia; Stoppa, Caroline Lais; Valduga, Claudete Justina; Okuyama, Cristina Eunice; Gorjão, Renata; Pereira, Regina Mara Silva; Diniz, Susana Nogueira

2017-03-30

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a new class of anti-diabetic agents that are widely used in clinical practice to improve glycemic control in patients with type 2 diabetes. DPP-4 is also known as lymphocyte cell surface protein, CD26, and plays an important role in T-cell immunity. Recent studies suggest that DPP-4 inhibitors improve beta-cell function and attenuate autoimmunity in type 1 diabetic mouse models. To investigate the direct effect of DPP4 in immune response, human peripheral blood mononuclear cells (PBMC) from healthy volunteers were obtained by Ficoll gradient and cultivated in the absence (control) or presence of phytohemagglutinin (PHA), or stimulated with PHA and treated with sitagliptin. The immune modulation mechanisms analyzed were: cell proliferation, by MTT assay; cytokine quantification by ELISA or cytometric bead array (CBA), Th1/Th2/Th17 phenotyping by flow cytometric analysis and CD26 gene expression by real time PCR. The results showed that sitagliptin treatment inhibited the proliferation of PBMC-PHA stimulated cells in a dose dependent manner and decreased CD26 expression by these cells, suggesting that sitagliptin may interfere in CD26 expression, dimerization and cell signaling. Sitagliptin treatment not only inhibited IL-10 (p<0.05) and IFN-gamma (p=0.07) cytokines, but also completely abolish IL-6 expression by PBMCs (p<0.001). On the other hand, IL-4 were secreted in culture supernatants from sitagliptin treated cells. A statistically significant increase (p<0.05) in the ratio of TGF-beta/proliferation index after sitagliptin treatment (2627.97±1351.65), when comparing to untreated cells (646.28±376.94), was also demonstrated, indicating higher TGF-beta1 production by viable cells in cultures. Sitagliptin treatment induced a significantly (p<0.05) decrease in IL-17 and IFN-gamma intracellular expression compared with PHA alone. Also, the percentage of T CD4 + IL-17 + , T CD4 + IFNgamma + and T CD4 + IL-4 + cells were significantly reduced (p<0.05) by sitagliptin. Our data demonstrated an immunosuppressive effect of sitagliptin on Th1, Th17 and Th2 lymphocytes differentiation that leads to the generation of regulatory TGF-beta1 secreting cells with low CD26 gene expression that may influence the state of pancreatic beta-cells and controlling DM1 patients. Copyright © 2017 Elsevier B.V. All rights reserved.

Neural cell adhesion molecule-deficient beta-cell tumorigenesis results in diminished extracellular matrix molecule expression and tumour cell-matrix adhesion.

PubMed

Håkansson, Joakim; Xian, Xiaojie; He, Liqun; Ståhlberg, Anders; Nelander, Sven; Samuelsson, Tore; Kubista, Mikael; Semb, Henrik

2005-01-01

To understand by which mechanism neural cell adhesion molecule (N-CAM) limits beta tumour cell disaggregation and dissemination, we searched for potential downstream genes of N-CAM during beta tumour cell progression by gene expression profiling. Here, we show that N-CAM-deficient beta-cell tumorigenesis is associated with changes in the expression of genes involved in cell-matrix adhesion and cytoskeletal dynamics, biological processes known to affect the invasive and metastatic behaviour of tumour cells. The extracellular matrix (ECM) molecules emerged as the primary target, i.e. N-CAM deficiency resulted in down-regulated mRNA expression of a broad range of ECM molecules. Consistent with this result, deficient deposition of major ECM stromal components, such as fibronectin, laminin 1 and collagen IV, was observed. Moreover, N-CAM-deficient tumour cells displayed defective matrix adhesion. These results offer a potential mechanism for tumour cell disaggregation during N-CAM-deficient beta tumour cell progression. Prospective consequences of these findings for the role of N-CAM in beta tumour cell dissemination are discussed.

Endothelin-converting enzyme 1 degrades neuropeptides in endosomes to control receptor recycling.

PubMed

Roosterman, Dirk; Cottrell, Graeme S; Padilla, Benjamin E; Muller, Laurent; Eckman, Christopher B; Bunnett, Nigel W; Steinhoff, Martin

2007-07-10

Neuropeptide signaling requires the presence of G protein-coupled receptors (GPCRs) at the cell surface. Activated GPCRs interact with beta-arrestins, which mediate receptor desensitization, endocytosis, and mitogenic signaling, and the peptide-receptor-arrestin complex is sequestered into endosomes. Although dissociation of beta-arrestins is required for receptor recycling and resensitization, the critical event that initiates this process is unknown. Here we report that the agonist availability in the endosomes, controlled by the membrane metalloendopeptidase endothelin-converting enzyme 1 (ECE-1), determines stability of the peptide-receptor-arrestin complex and regulates receptor recycling and resensitization. Substance P (SP) binding to the tachykinin neurokinin 1 receptor (NK1R) induced membrane translocation of beta-arrestins followed by trafficking of the SP-NK1R-beta-arrestin complex to early endosomes containing ECE-1a-d. ECE-1 degraded SP in acidified endosomes, disrupting the complex; beta-arrestins returned to the cytosol, and the NK1R, freed from beta-arrestins, recycled and resensitized. An ECE-1 inhibitor, by preventing NK1R recycling in endothelial cells, inhibited resensitization of SP-induced inflammation. This mechanism is a general one because ECE-1 similarly regulated NK3R resensitization. Thus, peptide availability in endosomes, here regulated by ECE-1, determines the stability of the peptide-receptor-arrestin complex. This mechanism regulates receptor recycling, which is necessary for sustained signaling, and it may also control beta-arrestin-dependent mitogenic signaling of endocytosed receptors. We propose that other endosomal enzymes and transporters may similarly control the availability of transmitters in endosomes to regulate trafficking and signaling of GPCRs. Antagonism of these endosomal processes represents a strategy for inhibiting sustained signaling of receptors, and defects may explain the tachyphylaxis of drugs that are receptor agonists.

Beta particle monitor for surfaces

DOEpatents

MacArthur, Duncan W.

1997-01-01

A beta radiation detector which is capable of reliably detecting beta radiation emitted from a surface. An electrically conductive signal collector is adjustably mounted inside an electrically conductive enclosure which may define a single large opening for placing against a surface. The adjustable mounting of the electrically conductive signal collector can be based on the distance from the surface or on the expected beta energy range. A voltage source is connected to the signal collector through an electrometer or other display means for creating an electric field between the signal collector and the enclosure. Air ions created by the beta radiation are collected and the current produced is indicated on the electrometer or other display means.

Beta particle monitor for surfaces

DOEpatents

MacArthur, D.W.

1997-10-21

A beta radiation detector which is capable of reliably detecting beta radiation emitted from a surface. An electrically conductive signal collector is adjustably mounted inside an electrically conductive enclosure which may define a single large opening for placing against a surface. The adjustable mounting of the electrically conductive signal collector can be based on the distance from the surface or on the expected beta energy range. A voltage source is connected to the signal collector through an electrometer or other display means for creating an electric field between the signal collector and the enclosure. Air ions created by the beta radiation are collected and the current produced is indicated on the electrometer or other display means. 2 figs.

The involvement of AMPK/GSK3-beta signals in the control of metastasis and proliferation in hepato-carcinoma cells treated with anthocyanins extracted from Korea wild berry Meoru

PubMed Central

2014-01-01

Background Activation of the Wnt pathway is known to promote tumorigenesis and tumor metastasis, and targeting Wnt pathway inhibition has emerged as an attractive approach for controlling tumor invasion and metastasis. The major pathway for inhibiting Wnt is through the degradation of β-catenin by the GSK3-beta/CK1/Axin/APC complex. It was found that Hep3B hepato-carcinoma cells respond to anthocyanins through GSK3-beta-induced suppression of beta-catenin; however, they cannot dephosphorylate GSK3-beta without AMPK activation. Methods We tested the effects of anthocyanins on proliferation and apoptosis by MTT and Annexin V-PI staining in vitro. Mouse xenograft models of hepato-carcinomas were established by inoculation with Hep3B cells, and mice were injected with 50 mg/kg/ml of anthocyanins. In addition, protein levels of p-GSK3-beta, beta-catenin, p-AMPK, MMP-9, VEGF, and Ang-1 were also analyzed using western blot. Results Anthocyanins decrease phospho-GSK3-beta and beta-catenin expression in an in vivo tumor xenograft model, increase AMPK activity in this model, and inhibit cell migration and invasion, possibly by inhibiting MMP-2 (in vitro) and the panendothelial marker, CD31 (in vivo). To elucidate the role of the GSK3-beta/beta-catenin pathway in cancer control, we conditionally inactivated this pathway, using activated AMPK for inhibition. Further, we showed that AMPK siRNA treatment abrogated the ability of anthocyanins to control cell proliferation and metastatic potential, and Compound C, an AMPK inhibitor, could not restore GSK3-beta regulation, as exhibited by anthocyanins in Hep3B cells. Conclusion These observations imply that the AMPK-mediated GSK3-beta/beta-catenin circuit plays crucial roles in inhibiting cancer cell proliferation and metastasis in anthocyanin-treated hepato-carcinoma cells of Meoru origin. PMID:24666969

Characterization of a beta-glycosidase highly active on disaccharides and of a beta-galactosidase from Tenebrio molitor midgut lumen.

PubMed

Ferreira, Alexandre H P; Terra, Walter R; Ferreira, Clélia

2003-02-01

The midgut of the yellow mealworm, Tenebrio molitor L. (Coleoptera: Tenebrionidae) larvae has four beta-glycosidases. The properties of two of these enzymes (betaGly1 and betaGly2) have been described elsewhere. In this paper, the characterization of the other two glycosidases (betaGly3 and betaGly4) is described. BetaGly3 has one active site, hydrolyzes disaccharides, cellodextrins, synthetic substrates and beta-glucosides produced by plants. The enzyme is inhibited by amygdalin, cellotriose, cellotetraose and cellopentaose in high concentrations, probably due to transglycosylation. betaGly3 hydrolyzes beta 1,4-glycosidic linkages with a catalytic rate independent of the substrate polymerization degree (k(int)) of 11.9 s(-1). Its active site is formed by four subsites, where subsites +1 and -1 bind glucose residues with higher affinity than subsite +2. The main role of betaGly3 seems to be disaccharide hydrolysis. BetaGly4 is a beta-galactosidase, since it has highest activity against beta-galactosides. It can also hydrolyze fucosides, but not glucosides, and has Triton X-100 as a non-essential activator (K(a)=15 microM, pH 4.5). betaGly4 has two active sites that can hydrolyze p-nitrophenyl beta-galactoside (NPbetaGal). The one hydrolyzing NPbetaGal with more efficiency is also active against methylumbellipheryl beta-D-galactoside and lactose. The other active site hydrolyzes NPbetaFucoside and binds NPbetaGal weakly. BetaGly4 hydrolyzes hydrophobic substrates with high catalytical efficiency and is able to bind octyl-beta-thiogalactoside in its active site with high affinity. The betaGly4 physiological role is supposed to be the hydrolysis of galactolipids that are found in membranes from vegetal tissues. As the enzyme has a hydrophobic site where Triton X-100 can bind, it might be activated by membrane lipids, thus becoming fully active only at the surface of cell membranes.

The structure of myostatin:follistatin 288: insights into receptor utilization and heparin binding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cash, Jennifer N.; Rejon, Carlis A.; McPherron, Alexandra C.

2009-09-29

Myostatin is a member of the transforming growth factor-{beta} (TGF-{beta}) family and a strong negative regulator of muscle growth. Here, we present the crystal structure of myostatin in complex with the antagonist follistatin 288 (Fst288). We find that the prehelix region of myostatin very closely resembles that of TGF-{beta} class members and that this region alone can be swapped into activin A to confer signalling through the non-canonical type I receptor Alk5. Furthermore, the N-terminal domain of Fst288 undergoes conformational rearrangements to bind myostatin and likely acts as a site of specificity for the antagonist. In addition, a unique continuousmore » electropositive surface is created when myostatin binds Fst288, which significantly increases the affinity for heparin. This translates into stronger interactions with the cell surface and enhanced myostatin degradation in the presence of either Fst288 or Fst315. Overall, we have identified several characteristics unique to myostatin that will be paramount to the rational design of myostatin inhibitors that could be used in the treatment of muscle-wasting disorders.« less

The J beta segment of the T cell receptor contributes to the V beta-specific T cell expansion caused by staphylococcal enterotoxin B and Urtica dioica superantigens.

PubMed

Musette, P; Galelli, A; Truffa-Bachi, P; Peumans, W; Kourilsky, P; Gachelin, G

1996-03-01

We have used a new polymerase chain reaction-based technique to analyze at the clonal level the CDR3 diversity and the J beta usage associated with the V beta-dependent T cell receptor (TCR) recognition of two superantigens: the staphylococcal enterotoxin B and the Urtica dioica agglutinin. Our results show that subset of J beta elements is preferentially expanded in a given V beta family, independently of the nature of the superantigen. By contrast, the CDR3 loop does not contribute significantly to the T cell expansion induced by the superantigens. We conclude that the J beta segment of the TCR beta chain, but not the CDR3 region, participates in superantigen binding, presumably by influencing the quaternary structure of the TCR beta chain.

The mechanism of cell death in human cultured colon adenocarcinoma cell line COLO 201 induced by beta-D-N-acetylglucosaminyl-p-nitrophenol.

PubMed

Kukidome, J; Kakizaki, I; Takagaki, K; Matsuki, A; Munakata, A; Endo, M

2001-05-01

COLO 201, human colon adenocarcinoma cells were incubated with artificial primers, p-nitrophenyl-glycoside derivatives at 1.0 mmol (mM) in the medium containing 10% fetal bovine serum to detect sugar chain elongation. However, when p-nitrophenyl-beta-N-acetylglucosamine (beta-GlcNAc-PNP) was added, the medium changed color to yellow and the cells were dead. To explain this finding, the cells were incubated with 1.0 mM each of beta-GlcNAc-PNP and 4-methylumbelliferyl-beta-N-acetylglucosamine, then the number of living cells was measured in a time course. In beta-GlcNAc-PNP, the living cells were decreased at 24 hours. The cells were survived with N-acetylglucosamine, whereas in the presence of p-nitrophenol (PNP) the living cells were decreased. It was suggested that PNP released from beta-GlcNAc-PNP induced the cell death. Activity of beta-D-N-acetylglucosaminidase was detected in fetal bovine serum. It was shown that PNP induced the cell death in time-and-dose dependent manner. Genomic DNA from COLO 201 analyzed by agarose gel electrophoresis was fragmentated. PNP analogues were tested for toxicity, and the results suggested that the phenolic OH-group linked to benzene ring and nitro-group linked to the structure in para-form (PNP) was the most effective.

Synthesis and cytotoxic analysis of some disodium 3beta,6beta-dihydroxysterol disulfates.

PubMed

Cui, Jianguo; Wang, Hui; Huang, Yanmin; Xin, Yi; Zhou, Aimin

2009-01-01

Disodium 3beta,6beta-dihydroxy-5alpha-cholestane disulfate (1) was synthesized in 4 steps with a high overall yield from cholesterol. First, cholesterol (4a) was converted to cholest-4-en-3,6-dione (5a) via oxidation with pyridinium chlorochromate (PCC) and then 5a was reduced by NaBH(4) in the presence of NiCl(2) to produce cholest-3beta,6beta-diol (6a). The reaction of 6a with the triethylamine-sulfur trioxide complex generated diammonium 3beta,6beta-dihydroxy-5alpha-cholestane disulfate (7a) and the treatment of 7a by cation exchange resin 732 (sodium form)(Na(+)) yielded the target steroid 1. Disodium 24-ethyl-3beta,6beta-dihydroxycholest-22-ene disulfate (2) and disodium 24-ethyl-3beta,6beta-dihydroxycholestane disulfate (3) were synthesized using a similar method. The cytotoxicity of these compounds against Sk-Hep-1 (human liver carcinoma cell line), H-292 (human lung carcinoma cell line), PC-3 (human prostate carcinoma cell line) and Hey-1B (human ovarian carcinoma cell line) cells was investigated. Our results indicate that presence of a cholesterol-type side chain at position 17 is necessary for their biological activity.

AMP-activated protein kinase (AMPK) cross-talks with canonical Wnt signaling via phosphorylation of {beta}-catenin at Ser 552

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Junxing; Yue, Wanfu; Zhu, Mei J.

AMP-activated protein kinase (AMPK) is a key regulator of energy metabolism; its activity is regulated by a plethora of physiological conditions, exercises and many anti-diabetic drugs. Recent studies show that AMPK involves in cell differentiation but the underlying mechanism remains undefined. Wingless Int-1 (Wnt)/{beta}-catenin signaling pathway regulates the differentiation of mesenchymal stem cells through enhancing {beta}-catenin/T-cell transcription factor 1 (TCF) mediated transcription. The objective of this study was to determine whether AMPK cross-talks with Wnt/{beta}-catenin signaling through phosphorylation of {beta}-catenin. C3H10T1/2 mesenchymal cells were used. Chemical inhibition of AMPK and the expression of a dominant negative AMPK decreased phosphorylation ofmore » {beta}-catenin at Ser 552. The {beta}-catenin/TCF mediated transcription was correlated with AMPK activity. In vitro, pure AMPK phosphorylated {beta}-catenin at Ser 552 and the mutation of Ser 552 to Ala prevented such phosphorylation, which was further confirmed using [{gamma}-{sup 32}P]ATP autoradiography. In conclusion, AMPK phosphorylates {beta}-catenin at Ser 552, which stabilizes {beta}-catenin, enhances {beta}-catenin/TCF mediated transcription, expanding AMPK from regulation of energy metabolism to cell differentiation and development via cross-talking with the Wnt/{beta}-catenin signaling pathway.« less

beta-catenin mediates insulin-like growth factor-I actions to promote cyclin D1 mRNA expression, cell proliferation and survival in oligodendroglial cultures.

PubMed

Ye, Ping; Hu, Qichen; Liu, Hedi; Yan, Yun; D'ercole, A Joseph

2010-07-01

By promoting cell proliferation, survival and maturation insulin-like growth factor (IGF)-I is essential to the normal growth and development of the central nervous system. It is clear that IGF-I actions are primarily mediated by the type I IGF receptor (IGF1R), and that phosphoinositide 3 (PI3)-Akt kinases and MAP kinases signal many of IGF-I-IGF1R actions in neural cells, including oligodendrocyte lineage cells. The precise downstream targets of these signaling pathways, however, remain to be defined. We studied oligodendroglial cells to determine whether beta-catenin, a molecule that is a downstream target of glycogen synthase kinase-3beta (GSK3beta) and plays a key role in the Wnt canonical signaling pathway, mediates IGF-I actions. We found that IGF-I increases beta-catenin protein abundance within an hour after IGF-I-induced phosphorylation of Akt and GSK3beta. Inhibiting the PI3-Akt pathway suppressed IGF-I-induced increases in beta-catenin and cyclin D1 mRNA, while suppression of GSK3beta activity simulated IGF-I actions. Knocking-down beta-catenin mRNA by RNA interference suppressed IGF-I-stimulated increases in the abundance of cyclin D1 mRNA, cell proliferation, and cell survival. Our data suggest that beta-catenin is an important downstream molecule in the PI3-Akt-GSK3beta pathway, and as such it mediates IGF-I upregulation of cyclin D1 mRNA and promotion of cell proliferation and survival in oligodendroglial cells. Copyright 2010 Wiley-Liss, Inc.

Inhibitory effect of dimeric beta peptide on the recurrence and metastasis of hepatocellular carcinoma in vitro and in mice.

PubMed

Wang, Song-Mei; Zhu, Jun; Pan, Luan-Feng; Liu, Yin-Kun

2008-05-21

To block the adhesion of tumor cells to the extracellular matrix, and prevent tumor metastasis and recurrence, the dimer of the beta peptide (DLYYLMDLSYSMKGGDLYYLMDLSYSMK, beta2) was designed and synthesized and its anti-adhesion and anti-invasion effects on hepatocellular carcinoma cells were assessed. Additionally, its influence on the metastasis and recurrence of mouse hepatocellular carcinoma was measured. The anti-adhesion effect of beta2 on the highly metastatic hepatocellular carcinoma cell line HCCLM6 cells and fibronectin (FN) was assayed by the MTT assay. The inhibition of invasion of HCCLM6 cells by beta2 was observed using a Transwell (modified Boyden chamber) and matrigel. Using the hepatocellular carcinoma metastasis model and LCI-D20 nude mice, the influence of beta2 on the metastasis and recurrence of hepatocellular carcinoma after early resection was investigated. HCCLM6 cells co-incubated with 100 mumol/L, 50 micromol/L, 20 micromol/L or 10 micromol/L beta2 for 3 h showed an obvious decrease in adhesion to FN. The adhesion inhibition ratios were 11.8%, 21.7%, 29.6% and 48.7%, respectively. Additionally, HCCLM6 cells cultured with 100 mumol/L beta2 had a dramatic decrease in cell invasion. beta2 was also observed to inhibit the incisal edge recurrence and the distant metastasis of nude mice hepatocellular carcinoma after early resection (P < 0.05). The beta2 peptide can specifically block the adhesion and invasion of HCCLM6 cells, and can inhibit HCC recurrence and metastasis of LCI-D20 model posthepatectomy in vivo. Thus, beta2 should be further studied as a new anti-tumor drug.

Proteomic profiling of bone marrow mesenchymal stem cells upon TGF-beta stimulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Daojing; Park, Jennifer S.; Chu, Julia S.F.

Bone marrow mesenchymal stem cells (MSCs) can differentiate into different types of cells, and have tremendous potential for cell therapy and tissue engineering. Transforming growth factor {beta}1 (TGF-{beta}) plays an important role in cell differentiation and vascular remodeling. We showed that TGF-{beta} induced cell morphology change and an increase in actin fibers in MSCs. To determine the global effects of TGF-{beta} on MSCs, we employed a proteomic strategy to analyze the effect of TGF-{beta} on the human MSC proteome. By using two-dimensional gel electrophoresis and electrospray ionization coupled to Quadrupole/time-of-flight tandem mass spectrometers, we have generated a proteome reference mapmore » of MSCs, and identified {approx}30 proteins with an increase or decrease in expression or phosphorylation in response to TGF-{beta}. The proteins regulated by TGF-{beta} included cytoskeletal proteins, matrix synthesis proteins, membrane proteins, metabolic enzymes, etc. TGF-{beta} increased the expression of smooth muscle (SM) {alpha}-actin and decreased the expression of gelsolin. Over-expression of gelsolin inhibited TGF-{beta}-induced assembly of SM {alpha}-actin; on the other hand, knocking down gelsolin expression enhanced the assembly of {alpha}-actin and actin filaments without significantly affecting {alpha}-actin expression. These results suggest that TGF-{beta} coordinates the increase of {alpha}-actin and the decrease of gelsolin to promote MSC differentiation. This study demonstrates that proteomic tools are valuable in studying stem cell differentiation and elucidating the underlying molecular mechanisms.« less

Phototoxic effects of an operating microscope on the ocular surface and tear film.

PubMed

Hwang, Hyung Bin; Kim, Hyun Seung

2014-01-01

We evaluated light exposure-induced dry eye syndrome by investigating the phototoxic effects of an operating microscope on the ocular surface and tear film in rabbits. Sixty eyes of 30 rabbits were divided into 3 groups based on the intensity of light exposure received from an operating microscope: Control group, no exposure to light; group A, 40,000-lx intensity for 30 minutes; and group B, 100,000-lx intensity for 30 minutes. To evaluate the potential damage to the ocular surface and tear film, Schirmer tests, rose bengal staining, and conjunctival impression cytology were performed before the light exposure and at 1, 3, and 5 days afterward. In addition, the expression of interleukin 1-beta was analyzed in tear samples. The expression of mucin 5AC was evaluated using immunofluorescence staining, and periodic acid-Schiff staining was conducted on conjunctival tissues. Corneal and conjunctival tissues were observed by means of electron microscopy. Potential damage to the ocular surface and tear film was found in the light-exposed groups as evidenced by decreased aqueous tear production, devitalized corneal and conjunctival epithelial cells, squamous metaplasia of conjunctival epithelial cells, decreased conjunctival goblet cell density, decreased expression of mucin 5AC, ultrastructural cellular damage to corneal and conjunctival tissues, and increased interleukin 1-beta expression in tears. This damage was more noticeable in group B than in group A (P < 0.05). Light exposure from an operating microscope had phototoxic effects on the ocular surface and tear film in this in vivo experiment. These changes seemed to intensify as the intensity of the light increased. Therefore, excessive light exposure during ophthalmic procedures could be a pathogenic factor in dry eye syndrome after a surgery is performed.

Proteomic Plasma Membrane Profiling Reveals an Essential Role for gp96 in the Cell Surface Expression of LDLR Family Members, Including the LDL Receptor and LRP6

PubMed Central

2012-01-01

The endoplasmic reticulum chaperone gp96 is required for the cell surface expression of a narrow range of proteins, including toll-like receptors (TLRs) and integrins. To identify a more comprehensive repertoire of proteins whose cell surface expression is dependent on gp96, we developed plasma membrane profiling (PMP), a technique that combines SILAC labeling with selective cell surface aminooxy-biotinylation. This approach allowed us to compare the relative abundance of plasma membrane (PM) proteins on gp96-deficient versus gp96-reconstituted murine pre-B cells. Analysis of unfractionated tryptic peptides initially identified 113 PM proteins, which extended to 706 PM proteins using peptide prefractionation. We confirmed a requirement for gp96 in the cell surface expression of certain TLRs and integrins and found a marked decrease in cell surface expression of four members of the extended LDL receptor family (LDLR, LRP6, Sorl1 and LRP8) in the absence of gp96. Other novel gp96 client proteins included CD180/Ly86, important in the B-cell response to lipopolysaccharide. We highlight common structural motifs in these client proteins that may be recognized by gp96, including the beta-propeller and leucine-rich repeat. This study therefore identifies the extended LDL receptor family as an important new family of proteins whose cell surface expression is regulated by gp96. PMID:22292497

Proteomic plasma membrane profiling reveals an essential role for gp96 in the cell surface expression of LDLR family members, including the LDL receptor and LRP6.

PubMed

Weekes, Michael P; Antrobus, Robin; Talbot, Suzanne; Hör, Simon; Simecek, Nikol; Smith, Duncan L; Bloor, Stuart; Randow, Felix; Lehner, Paul J

2012-03-02

The endoplasmic reticulum chaperone gp96 is required for the cell surface expression of a narrow range of proteins, including toll-like receptors (TLRs) and integrins. To identify a more comprehensive repertoire of proteins whose cell surface expression is dependent on gp96, we developed plasma membrane profiling (PMP), a technique that combines SILAC labeling with selective cell surface aminooxy-biotinylation. This approach allowed us to compare the relative abundance of plasma membrane (PM) proteins on gp96-deficient versus gp96-reconstituted murine pre-B cells. Analysis of unfractionated tryptic peptides initially identified 113 PM proteins, which extended to 706 PM proteins using peptide prefractionation. We confirmed a requirement for gp96 in the cell surface expression of certain TLRs and integrins and found a marked decrease in cell surface expression of four members of the extended LDL receptor family (LDLR, LRP6, Sorl1 and LRP8) in the absence of gp96. Other novel gp96 client proteins included CD180/Ly86, important in the B-cell response to lipopolysaccharide. We highlight common structural motifs in these client proteins that may be recognized by gp96, including the beta-propeller and leucine-rich repeat. This study therefore identifies the extended LDL receptor family as an important new family of proteins whose cell surface expression is regulated by gp96.

Reduction of high-affinity beta2-adrenergic receptor binding by hyperforin and hyperoside on rat C6 glioblastoma cells measured by fluorescence correlation spectroscopy.

PubMed

Prenner, Lars; Sieben, Anne; Zeller, Karin; Weiser, Dieter; Häberlein, Hanns

2007-05-01

Beta-adrenergic receptors (beta-AR) are potential targets for antidepressants. Desensitization and downregulation of beta-AR are discussed as possible modes of action for antidepressants. We have investigated the effects of hyperforin and hyperoside, compounds with potentially antidepressant activity from St. John's Wort, on the binding behavior and dynamics of beta2-AR in living rat C6 glioblastoma cells, compared to desipramine (desmethylimipramine; DMI) by means of fluorescence correlation spectroscopy (FCS) and fluorescence microscopy. FCS-binding studies with the fluorescently labeled ligand Alexa532-noradrenaline (Alexa532-NA) binding to beta2-AR of C6 cells showed a significant reduction in total beta2-AR binding after preincubation with hyperforin and hyperoside for 3 days, respectively, which was also found for DMI. This was mainly observed in high-affinity receptor-ligand complexes with hindered lateral mobility (D2 = 1.1 (+/-0.4) microm2/s) in the biomembrane. However, internalization of beta2-AR was found neither in z-scans of these C6 cells nor in HEK 293 cells stably transfected with GFP-tagged beta2-adrenergic receptors (beta2AR-GFP) after incubation up to 6 days with either DMI, hyperforin, or hyperoside. Thus, under these conditions reduction of beta2-AR binding was not mediated by receptor internalization. Additionally, preincubation of C6 cells with DMI, hyperforin, and hyperoside led to a loss of second messenger cAMP after beta2-adrenergic stimulating conditions with terbutaline. Our current results indicate that hyperforin and hyperoside from St. John's Wort, as well as DMI, reduce beta2-adrenergic sensitivity in C6 cells, emphasizing the potential usefulness of St. John's Wort dry extracts in clinical treatment of depressive symptoms.

Transforming growth factor-beta regulates mammary carcinoma cell survival and interaction with the adjacent microenvironment.

PubMed

Bierie, Brian; Stover, Daniel G; Abel, Ty W; Chytil, Anna; Gorska, Agnieszka E; Aakre, Mary; Forrester, Elizabeth; Yang, Li; Wagner, Kay-Uwe; Moses, Harold L

2008-03-15

Transforming growth factor (TGF)-beta signaling has been associated with early tumor suppression and late tumor progression; however, many of the mechanisms that mediate these processes are not known. Using Cre/LoxP technology, with the whey acidic protein promoter driving transgenic expression of Cre recombinase (WAP-Cre), we have now ablated the type II TGF-beta receptor (T beta RII) expression specifically within mouse mammary alveolar progenitors. Transgenic expression of the polyoma virus middle T antigen, under control of the mouse mammary tumor virus enhancer/promoter, was used to produce mammary tumors in the absence or presence of Cre (T beta RII((fl/fl);PY) and T beta RII((fl/fl);PY;WC), respectively). The loss of TGF-beta signaling significantly decreased tumor latency and increased the rate of pulmonary metastasis. The loss of TGF-beta signaling was significantly correlated with increased tumor size and enhanced carcinoma cell survival. In addition, we observed significant differences in stromal fibrovascular abundance and composition accompanied by increased recruitment of F4/80(+) cell populations in T beta RII((fl/fl);PY;WC) mice when compared with T beta RII((fl/fl);PY) controls. The recruitment of F4/80(+) cells correlated with increased expression of known inflammatory genes including Cxcl1, Cxcl5, and Ptgs2 (cyclooxygenase-2). Notably, we also identified an enriched K5(+) dNp63(+) cell population in primary T beta RII((fl/fl);PY;WC) tumors and corresponding pulmonary metastases, suggesting that loss of TGF-beta signaling in this subset of carcinoma cells can contribute to metastasis. Together, our current results indicate that loss of TGF-beta signaling in mammary alveolar progenitors may affect tumor initiation, progression, and metastasis through regulation of both intrinsic cell signaling and adjacent stromal-epithelial interactions in vivo.

Influence and timing of arrival of murine neural crest on pancreatic beta cell development and maturation.

PubMed

Plank, Jennifer L; Mundell, Nathan A; Frist, Audrey Y; LeGrone, Alison W; Kim, Thomas; Musser, Melissa A; Walter, Teagan J; Labosky, Patricia A

2011-01-15

Interactions between cells from the ectoderm and mesoderm influence development of the endodermally-derived pancreas. While much is known about how mesoderm regulates pancreatic development, relatively little is understood about how and when the ectodermally-derived neural crest regulates pancreatic development and specifically, beta cell maturation. A previous study demonstrated that signals from the neural crest regulate beta cell proliferation and ultimately, beta cell mass. Here, we expand on that work to describe timing of neural crest arrival at the developing pancreatic bud and extend our knowledge of the non-cell autonomous role for neural crest derivatives in the process of beta cell maturation. We demonstrated that murine neural crest entered the pancreatic mesenchyme between the 26 and 27 somite stages (approximately 10.0 dpc) and became intermingled with pancreatic progenitors as the epithelium branched into the surrounding mesenchyme. Using a neural crest-specific deletion of the Forkhead transcription factor Foxd3, we ablated neural crest cells that migrate to the pancreatic primordium. Consistent with previous data, in the absence of Foxd3, and therefore the absence of neural crest cells, proliferation of insulin-expressing cells and insulin-positive area are increased. Analysis of endocrine cell gene expression in the absence of neural crest demonstrated that, although the number of insulin-expressing cells was increased, beta cell maturation was significantly impaired. Decreased MafA and Pdx1 expression illustrated the defect in beta cell maturation; we discovered that without neural crest, there was a reduction in the percentage of insulin-positive cells that co-expressed Glut2 and Pdx1 compared to controls. In addition, transmission electron microscopy analyses revealed decreased numbers of characteristic insulin granules and the presence of abnormal granules in insulin-expressing cells from mutant embryos. Together, these data demonstrate that the neural crest is a critical regulator of beta cell development on two levels: by negatively regulating beta cell proliferation and by promoting beta cell maturation. Copyright © 2010 Elsevier Inc. All rights reserved.

Preliminary in vivo efficacy studies of a recombinant rhesus anti-alpha(4)beta(7) monoclonal antibody.

PubMed

Pereira, L E; Onlamoon, N; Wang, X; Wang, R; Li, J; Reimann, K A; Villinger, F; Pattanapanyasat, K; Mori, K; Ansari, A A

2009-01-01

Recent findings established that primary targets of HIV/SIV are lymphoid cells within the gastrointestinal (GI) tract. Focus has therefore shifted to T-cells expressing alpha(4)beta(7) integrin which facilitates trafficking to the GI tract via binding to MAdCAM-1. Approaches to better understand the role of alpha(4)beta(7)+ T-cells in HIV/SIV pathogenesis include their depletion or blockade of their synthesis, binding and/or homing capabilities in vivo. Such studies can ideally be conducted in rhesus macaques (RM), the non-human primate model of AIDS. Characterization of alpha(4)beta(7) expression on cell lineages in RM blood and GI tissues reveal low densities of expression by NK cells, B-cells, naïve and TEM (effector memory) T-cells. High densities were observed on TCM (central memory) T-cells. Intravenous administration of a single 50mg/kg dose of recombinant rhesus alpha(4)beta(7) antibody resulted in significant initial decline of alpha(4)beta(7)+ lymphocytes and sustained coating of the alpha(4)beta(7) receptor in both the periphery and GI tissues.

Chimeras of the integrin beta subunit mid-region reveal regions required for heterodimer formation and for activation.

PubMed

Hyland, R H; Douglass, W A; Tan, S M; Law, S K

2001-01-01

A central region of the beta2 integrin subunit, RN (residues D300 to C459), was replaced by the equivalent sequences from beta1 and beta7 to give the chimeras beta2RN1 and beta2RN7. Whilst the former construct failed to form heterodimer at the cell surface with alphaL, the later of these could be expressed together with the alphaL subunit to form a variant LFA-1. Based on recent modelling work, the RN region consists of two parts, one is the C-terminal end of the putative A-domain (RB, residues D300 to A359), and the other the mid-region (BN, residues Y360 to C459). Chimeras exchanging the two component regions were made. Of the four resultant chimeras, only the beta2RB1 chimera failed to support LFA-1 expression. Thus the beta1 specific residues of this region affect the interaction with the alphaL subunit. Whereas the alphaL/beta2RB7 LFA-1 variant is wildtype like with respect to ICAM-1 adhesion, the alphaLbeta2BN1 and alphaLbeta2BN7, as well as the alphaLbeta2RN7, variants are more adhesive than the wildtype. These results suggest that an authentic beta2 mid-region is, in part, required for maintaining the LFA-1 in a resting state.

Tumor-produced, active Interleukin-1 {beta} regulates gene expression in carcinoma-associated fibroblasts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dudas, Jozsef, E-mail: Jozsef.Dudas@i-med.ac.at; Fullar, Alexandra, E-mail: fullarsz@gmail.com; 1st Institute of Pathology and Experimental Cancer Research, Semmelweis University, Ulloei ut 26, H-1085 Budapest

2011-09-10

Recently we described a co-culture model of periodontal ligament (PDL) fibroblasts and SCC-25 lingual squamous carcinoma cells, which resulted in conversion of normal fibroblasts into carcinoma-associated fibroblasts (CAFs), and in epithelial-mesenchymal transition (EMT) of SCC-25 cells. We have found a constitutive high interleukin-1{beta} (IL1-{beta}) expression in SCC-25 cells in normal and in co-cultured conditions. In our hypothesis a constitutive IL1-{beta} expression in SCC-25 regulates gene expression in fibroblasts during co-culture. Co-cultures were performed between PDL fibroblasts and SCC-25 cells with and without dexamethasone (DEX) treatment; IL1-{beta} processing was investigated in SCC-25 cells, tumor cells and PDL fibroblasts were treated withmore » IL1-{beta}. IL1-{beta} signaling was investigated by western blot and immunocytochemistry. IL1-{beta}-regulated genes were analyzed by real-time qPCR. SCC-25 cells produced 16 kD active IL1-{beta}, its receptor was upregulated in PDL fibroblasts during co-culture, which induced phosphorylation of interleukin-1 receptor-associated kinase-1 (IRAK-1), and nuclear translocalization of NF{kappa}B{alpha}. Several genes, including interferon regulatory factor 1 (IRF1) interleukin-6 (IL-6) and prostaglandin-endoperoxide synthase 2 (COX-2) were induced in CAFs during co-culture. The most enhanced induction was found for IL-6 and COX-2. Treatment of PDL fibroblasts with IL1-{beta} reproduced a time- and dose-dependent upregulation of IL1-receptor, IL-6 and COX-2. A further proof was achieved by DEX inhibition for IL1-{beta}-stimulated IL-6 and COX-2 gene expression. Constitutive expression of IL1-{beta} in the tumor cells leads to IL1-{beta}-stimulated gene expression changes in tumor-associated fibroblasts, which are involved in tumor progression. -- Graphical abstract: SCC-25 cells produce active, processed IL1-{beta}. PDL fibroblasts possess receptor for IL1-{beta}, and its expression is increased 4.56-times in the presence of SCC-25 tumor cells. IL1-{beta} receptor expression in fibroblasts, especially in CAFs represents a major option in coordination of fibroblast and tumor behavior. A key event in IL1-{beta} signaling, the phosphorylation of IRAK1, occurred in co-cultured fibroblasts, which has lead to nuclear translocation of NF{kappa}B{alpha}, and finally to induction of several genes, including BDNF, IRF1, IL-6 and COX-2. The most enhanced induction was found for IL-6 and COX-2.« less

Beta-lactamase induction and cell wall metabolism in Gram-negative bacteria

PubMed Central

Zeng, Ximin; Lin, Jun

2013-01-01

Production of beta-lactamases, the enzymes that degrade beta-lactam antibiotics, is the most widespread and threatening mechanism of antibiotic resistance. In the past, extensive research has focused on the structure, function, and ecology of beta-lactamases while limited efforts were placed on the regulatory mechanisms of beta-lactamases. Recently, increasing evidence demonstrate a direct link between beta-lactamase induction and cell wall metabolism in Gram-negative bacteria. Specifically, expression of beta-lactamase could be induced by the liberated murein fragments, such as muropeptides. This article summarizes current knowledge on cell wall metabolism, beta-lactam antibiotics, and beta-lactamases. In particular, we comprehensively reviewed recent studies on the beta-lactamase induction by muropeptides via two major molecular mechanisms (the AmpG–AmpR–AmpC pathway and BlrAB-like two-component regulatory system) in Gram-negative bacteria. The signaling pathways for beta-lactamase induction offer a broad array of promising targets for the discovery of new antibacterial drugs used for combination therapies. Therefore, to develop effective mitigation strategies against the widespread beta-lactam resistance, examination of the molecular basis of beta-lactamase induction by cell wall fragment is highly warranted. PMID:23734147

Bone-Induced Expression of Tumoral Integrin beta3 Enables Targeted Nanotherapy of Breast Cancer Metastases

NASA Astrophysics Data System (ADS)

Ross, Michael H.

Breast cancer is the most common cancer for women worldwide, representing approximately 25% of all new cancer cases in this population. While early detection and removal of breast cancer still confined to the primary site results in a good prognosis, approximately one- third of patients will develop distant metastases. In these patients, overall survival is markedly reduced. Of the common sites for breast cancer metastasis, the skeletal system is the most frequent. Treating breast cancer bone metastases has proven particularly difficult for several reasons, such as dissemination of metastases throughout the skeleton, poor drug localization to sites of interest, a lack of tumor-specific targets expressed across breast cancer subtypes, and the chemo-protective nature of the bone microenvironment. This dissertation is focused on investigating a potential tumor-target expressed on breast cancer bone metastases, and to improve drug treatment efficacy against tumor cells in the bone microenvironment. Integrins are heterodimeric cell surface receptors, composed of an alpha and beta subunit from a large family of selectively-compatible integrin subunits. As a heterodimeric complex, integrins can bind to components of the extracellular matrix or to other cells. One particular integrin complex, integrin alphavbeta3, is composed of the tightly regulated integrin subunit beta3 and the more widely expressed alphav subunit. I examined the expression of integrin beta3 on primary breast cancer as compared to metastases in murine cancer models, and observed that integrin expression is significantly elevated on bone metastases as compared to the primary tumors or visceral metastases. In addition, I evaluated tumor-associated integrin beta3 expression on a tissue microarray (TMA) composed of primary breast cancer and patient-matched bone metastatic tissue from 42 patients. Across nearly all patients, tumor-associated integrin beta3 expression was significantly elevated on bone metastases as compared to the primary tumor. For the first time, I demonstrate that tumor-associated integrin beta3 is elevated on bone metastases across all breast cancer subtypes, supporting the translational potential of targeting integrin beta3 in breast cancer patients with bone metastases. Integrin beta3 was weakly expressed on tumor cells in vitro and on tumor cells in the primary mammary fat pad (MFP). Additional analysis demonstrated that integrin beta3 on circulating tumor cells is dispensable for strong expression of integrin beta3 on subsequent bone metastases, suggested that integrin beta3 may be induced within the bone microenvironment. I identified transforming growth factor beta (TGF-beta) to be a potent inducer of integrin beta3 in vitro, and further demonstrate canonical TGF-beta signaling through the SMAD2 and SMAD3 (SMAD2/3) pathway is responsible for breast cancer upregulation of integrin beta3 induction on bone metastases, both in vitro and in vivo. Utilizing this information, I sought to evaluate the targeting potential of nanotherapy coated with a targeting ligand specific for integrin alphavbeta3. Nanotherapy has the potential to increase therapeutic efficacy and reduce toxicity versus traditional chemotherapies by enhancing drug delivery to specific targets of interest. I explored the localization potential of two nanoparticles with significantly different sizes: polysorbate (tween) 80 micelle nanoparticles (MPs, 12.5 nm) or perfluorocarbon (PFC) nanoparticles ( 250 nm). The smaller integrin alphavbeta3- targeted micelle nanoparticle (alphavbeta3-MP) could more effectively penetrate breast cancer bone metastases than larger integrin alphavbeta3-targeted PFC nanoparticles (alphavbeta3-PFCs). With these observations, I evaluated whether alphavbeta3-MP-mediated drug delivery could more effectively attenuate bone metastatic tumor burden and bone destruction than free drug delivery. Using the chemotherapeutic agent docetaxel (DTX), a potent microtubule inhibitor that is a first-line therapy for metastatic breast cancer, I observe that DTX is only weakly tumor- suppressive in our mouse model of breast cancer metastases. However, treating mice bearing breast cancer metastases with alphavbeta3-MP-delivery of a docetaxel-prodrug (DTX-PD) significantly reduced bone tumor burden and bone destruction, and with less hepatotoxicity. I observed a significant decrease in bone-residing tumor cell proliferation in mice treated with alphavbeta3-MP- delivery of DTX-PD, without overt osteoclast killing or inhibition of osteoclast formation. Together, these results provide support that nanotherapy-mediated attenuation of bone metastases and bone destruction occurs through enhanced drug efficacy against breast cancer cells within the bone. In this Dissertation, Chapter 1 will provide an overview of breast cancer, bone metastases, integrins, and the therapeutic potential of nanotherapy. In Chapter 2, my work on the expression and physiologic regulation of integrin beta3 on breast cancer during metastases will be explored. In Chapter 3, the role of the cytokine TGF-beta in regulating tumoral expression of integrin beta3 will be discussed. And in Chapter 4, I discuss the use of integrin alphavbeta3-targeted nanotherapy directed against breast cancer metastases. Collectively, I provide evidence that chemotherapeutic efficacy against breast cancer cells within bone can be enhanced by exploiting the expression of tumoral integrin beta3 at that metastatic site.

Inhibition of Transforming Growth Factor-Beta1 SignalingAttenuates Ataxia Telangiectasia Mutated Activity in Response toGenotoxic Stress

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kirshner, Julia; Jobling, Michael F.; Pajares, Maria Jose

2006-01-01

Ionizing radiation causes DNA damage that elicits a cellular program of damage control coordinated by the kinase activity of ataxia telangiectasia mutated protein (ATM). Transforming growth factor {beta} (TGF{beta})-1, which is activated by radiation, is a potent and pleiotropic mediator of physiologic and pathologic processes. Here we show that TGF{beta} inhibition impedes the canonical cellular DNA damage stress response. Irradiated Tgf{beta}I null murine epithelial cells or human epithelial cells treated with a small-molecule inhibitor of TGF{beta} type I receptor kinase exhibit decreased phosphorylation of Chk2, Rad17, and p53; reduced H2AX radiation-induced foci; and increased radiosensitivity compared with TGF{beta} competent cells.more » We determined that loss of TGF{beta} signaling in epithelial cells truncated ATM autophosphorylation and significantly reduced its kinase activity, without affecting protein abundance. Addition of TGF{beta} restored functional ATM and downstream DNA damage responses. These data reveal a heretofore undetected critical link between the microenvironment and ATM, which directs epithelial cell stress responses, cell fate, and tissue integrity. Thus, Tgf{beta}I, in addition to its role in homoeostatic growth control, plays a complex role in regulating responses to genotoxic stress, the failure of which would contribute to the development of cancer; conversely, inhibiting TGF{beta} may be used to advantage in cancer therapy.« less

WNT signaling controls expression of pro-apoptotic BOK and BAX in intestinal cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zeilstra, Jurrit; Joosten, Sander P.J.; Wensveen, Felix M.

Research highlights: {yields} Intestinal adenomas initiated by aberrant activation of the WNT pathway displayed an increased sensitivity to apoptosis. {yields} Expression profiling of apoptosis-related genes in Apc{sup Min/+} mice revealed the differential expression of pro-apoptotic Bok and Bax. {yields} APC-mutant adenomatous crypts in FAP patients showed strongly increased BAX immunoreactivity. {yields} Blocking of {beta}-catenin/TCF-4-mediated signaling in colon cancer cells reduced the expression of BOK and BAX. -- Abstract: In a majority of cases, colorectal cancer is initiated by aberrant activation of the WNT signaling pathway. Mutation of the genes encoding the WNT signaling components adenomatous polyposis coli or {beta}-catenin causesmore » constitutively active {beta}-catenin/TCF-mediated transcription, driving the transformation of intestinal crypts to cancer precursor lesions, called dysplastic aberrant crypt foci. Deregulated apoptosis is a hallmark of adenomatous colon tissue. However, the contribution of WNT signaling to this process is not fully understood. We addressed this role by analyzing the rate of epithelial apoptosis in aberrant crypts and adenomas of the Apc{sup Min/+} mouse model. In comparison with normal crypts and adenomas, aberrant crypts displayed a dramatically increased rate of apoptotic cell death. Expression profiling of apoptosis-related genes along the crypt-villus axis and in Apc mutant adenomas revealed increased expression of two pro-apoptotic Bcl-2 family members in intestinal adenomas, Bok and Bax. Analysis of the colon of familial adenomatous polyposis (FAP) patients along the crypt-to-surface axis, and of dysplastic crypts, corroborated this expression pattern. Disruption of {beta}-catenin/TCF-4-mediated signaling in the colorectal cancer cell line Ls174T significantly decreased BOK and BAX expression, confirming WNT-dependent regulation in intestinal epithelial cells. Our results suggest a feedback mechanism by which uncontrolled epithelial cell proliferation in the stem cell compartment can be counterbalanced by an increased propensity to undergo cell death.« less

Mechanotransduction across the cell surface and through the cytoskeleton

NASA Technical Reports Server (NTRS)

Wang, N.; Butler, J. P.; Ingber, D. E.

1993-01-01

Mechanical stresses were applied directly to cell surface receptors with a magnetic twisting device. The extracellular matrix receptor, integrin beta 1, induced focal adhesion formation and supported a force-dependent stiffening response, whereas nonadhesion receptors did not. The cytoskeletal stiffness (ratio of stress to strain) increased in direct proportion to the applied stress and required intact microtubules and intermediate filaments as well as microfilaments. Tensegrity models that incorporate mechanically interdependent struts and strings that reorient globally in response to a localized stress mimicked this response. These results suggest that integrins act as mechanoreceptors and transmit mechanical signals to the cytoskeleton. Mechanotransduction, in turn, may be mediated simultaneously at multiple locations inside the cell through force-induced rearrangements within a tensionally integrated cytoskeleton.

β-Arrestin2 plays a key role in the modulation of the pancreatic beta cell mass in mice.

PubMed

Ravier, Magalie A; Leduc, Michele; Richard, Joy; Linck, Nathalie; Varrault, Annie; Pirot, Nelly; Roussel, Morgane M; Bockaert, Joël; Dalle, Stéphane; Bertrand, Gyslaine

2014-03-01

Beta cell failure due to progressive secretory dysfunction and limited expansion of beta cell mass is a key feature of type 2 diabetes. Beta cell function and mass are controlled by glucose and hormones/neurotransmitters that activate G protein-coupled receptors or receptor tyrosine kinases. We have investigated the role of β-arrestin (ARRB)2, a scaffold protein known to modulate such receptor signalling, in the modulation of beta cell function and mass, with a specific interest in glucagon-like peptide-1 (GLP-1), muscarinic and insulin receptors. β-arrestin2-knockout mice and their wild-type littermates were fed a normal or a high-fat diet (HFD). Glucose tolerance, insulin sensitivity and insulin secretion were assessed in vivo. Beta cell mass was evaluated in pancreatic sections. Free cytosolic [Ca(2+)] and insulin secretion were determined using perifused islets. The insulin signalling pathway was evaluated by western blotting. Arrb2-knockout mice exhibited impaired glucose tolerance and insulin secretion in vivo, but normal insulin sensitivity compared with wild type. Surprisingly, the absence of ARRB2 did not affect glucose-stimulated insulin secretion or GLP-1- and acetylcholine-mediated amplifications from perifused islets, but it decreased the islet insulin content and beta cell mass. Additionally, there was no compensatory beta cell mass expansion through proliferation in response to the HFD. Furthermore, Arrb2 deletion altered the islet insulin signalling pathway. ARRB2 is unlikely to be involved in the regulation of insulin secretion, but it is required for beta cell mass plasticity. Additionally, we provide new insights into the mechanisms involved in insulin signalling in beta cells.

Intestinal inflammation reduces expression of DRA, a transporter responsible for congenital chloride diarrhea.

PubMed

Yang, H; Jiang, W; Furth, E E; Wen, X; Katz, J P; Sellon, R K; Silberg, D G; Antalis, T M; Schweinfest, C W; Wu, G D

1998-12-01

The pathogenesis of diarrhea in intestinal inflammatory states is a multifactorial process involving the effects of inflammatory mediators on epithelial transport function. The effect of colonic inflammation on the gene expression of DRA (downregulated in adenoma), a chloride-sulfate anion transporter that is mutated in patients with congenital chloridorrhea, was examined in vivo as well as in an intestinal epithelial cell line. DRA mRNA expression was diminished five- to sevenfold in the HLA-B27/beta2m transgenic rat compared with control. In situ hybridization showed that DRA, which is normally expressed in the upper crypt and surface epithelium of the colon, was dramatically reduced in the surface epithelium of the HLA-B27/beta2m transgenic rat, the interleukin-10 (IL-10) knockout mouse with spontaneous colitis, and in patients with ulcerative colitis. Immunohistochemistry demonstrated that mRNA expression of DRA reflected that of protein expression in vivo. IL-1beta reduced DRA mRNA expression in vitro by inhibiting gene transcription. The loss of transport function in the surface epithelium of the colon by attenuation of transporter gene expression, perhaps inhibited at the level of gene transcription by proinflammatory cytokines, may play a role in the pathogenesis of diarrhea in colitis.

Decursin suppresses human androgen-independent PC3 prostate cancer cell proliferation by promoting the degradation of beta-catenin.

PubMed

Song, Gyu-Yong; Lee, Jee-Hyun; Cho, Munju; Park, Byeoung-Soo; Kim, Dong-Eun; Oh, Sangtaek

2007-12-01

Alterations in the Wnt/beta-catenin pathway are associated with the development and progression of human prostate cancer. Decursin, a pyranocoumarin isolated from the Korean Angelica gigas root, inhibits the growth of androgen-independent human prostate cancer cells, but little is known about its mechanism of action. Using a cell-based screen, we found that decursin attenuates the Wnt/beta-catenin pathway. Decursin antagonized beta-catenin response transcription (CRT), which was induced with Wnt3a-conditioned medium and LiCl, by promoting the degradation of beta-catenin. Furthermore, decursin suppressed the expression of cyclin D1 and c-myc, which are downstream target genes of beta-catenin and thus inhibited the growth of PC3 prostate cancer cells. In contrast, decursinol, in which the (CH3)2-C=CH-COO- side chain of decursin is replaced with -OH, had no effect on CRT, the level of intracellular beta-catenin, or PC3 cell proliferation. Our findings suggest that decursin exerts its anticancer activity in prostate cancer cells via inhibition of the Wnt/beta-catenin pathway.

Mutant HNF-1{alpha} and mutant HNF-1{beta} identified in MODY3 and MODY5 downregulate DPP-IV gene expression in Caco-2 cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gu Ning; Laboratory of Neurochemistry, Graduate School of Human and Environmental Studies, Kyoto University, Kyoto; Adachi, Tetsuya

2006-08-04

Dipeptidylpeptidase IV (DPP-IV) is a well-documented drug target for the treatment of type 2 diabetes. Hepatocyte nuclear factors (HNF)-1{alpha} and HNF-1{beta}, known as the causal genes of MODY3 and MODY5, respectively, have been reported to be involved in regulation of DPP-IV gene expression. But, it is not completely clear (i) that they play roles in regulation of DPP-IV gene expression, and (ii) whether DPP-IV gene activity is changed by mutant HNF-1{alpha} and mutant HNF-1{beta} in MODY3 and MODY5. To explore these questions, we investigated transactivation effects of wild HNF-1{alpha} and 13 mutant HNF-1{alpha}, as well as wild HNF-1{beta} and 2more » mutant HNF-1{beta}, on DPP-IV promoter luciferase gene in Caco-2 cells by means of a transient experiment. Both wild HNF-1{alpha} and wild HNF-1{beta} significantly transactivated DPP-IV promoter, but mutant HNF-1{alpha} and mutant HNF-1{beta} exhibited low transactivation activity. Moreover, to study whether mutant HNF-1{alpha} and mutant HNF-1{beta} change endogenous DPP-IV enzyme activity, we produced four stable cell lines from Caco-2 cells, in which wild HNF-1{alpha} or wild HNF-1{beta}, or else respective dominant-negative mutant HNF-1{alpha}T539fsdelC or dominant-negative mutant HNF-1{beta}R177X, was stably expressed. We found that DPP-IV gene expression and enzyme activity were significantly increased in wild HNF-1{alpha} cells and wild HNF-1{beta} cells, whereas they decreased in HNF-1{alpha}T539fsdelC cells and HNF-1{beta}R177X cells, compared with DPP-IV gene expression and enzyme activity in Caco-2 cells. These results suggest that both wild HNF-1{alpha} and wild HNF-1{beta} have a stimulatory effect on DPP-IV gene expression, but that mutant HNF-1{alpha} and mutant HNF-1{beta} attenuate the stimulatory effect.« less

Surgical Injury to the Mouse Pancreas through Ligation of the Pancreatic Duct as a Model for Endocrine and Exocrine Reprogramming and Proliferation

PubMed Central

De Groef, Sofie; Leuckx, Gunter; Van Gassen, Naomi; Staels, Willem; Cai, Ying; Yuchi, Yixing; Coppens, Violette; De Leu, Nico; Heremans, Yves; Baeyens, Luc; Van de Casteele, Mark; Heimberg, Harry

2015-01-01

Expansion of pancreatic beta cells in vivo or ex vivo, or generation of beta cells by differentiation from an embryonic or adult stem cell, can provide new expandable sources of beta cells to alleviate the donor scarcity in human islet transplantation as therapy for diabetes. Although recent advances have been made towards this aim, mechanisms that regulate beta cell expansion and differentiation from a stem/progenitor cell remain to be characterized. Here, we describe a protocol for an injury model in the adult mouse pancreas that can function as a tool to study mechanisms of tissue remodeling and beta cell proliferation and differentiation. Partial duct ligation (PDL) is an experimentally induced injury of the rodent pancreas involving surgical ligation of the main pancreatic duct resulting in an obstruction of drainage of exocrine products out of the tail region of the pancreas. The inflicted damage induces acinar atrophy, immune cell infiltration and severe tissue remodeling. We have previously reported the activation of Neurogenin (Ngn) 3 expressing endogenous progenitor-like cells and an increase in beta cell proliferation after PDL. Therefore, PDL provides a basis to study signals involved in beta cell dynamics and the properties of an endocrine progenitor in adult pancreas. Since, it still remains largely unclear, which factors and pathways contribute to beta cell neogenesis and proliferation in PDL, a standardized protocol for PDL will allow for comparison across laboratories. PMID:26273954

Effect of interlukin-1beta on proliferation of gastric epithelial cells in culture.

PubMed

Beales, Ian L P

2002-04-05

Helicobacter pylori is the main risk factor for the development of non-cardia gastric cancer. Increased proliferation of the gastric mucosa is a feature of H. pylori infection. Mucosal interkeukin-1beta production is increased in H. pylori infection and IL-1beta genotypes associated with increased pro-inflammatory activity are risk factors for the development of gastric cancer. The effect of IL-1beta on gastric epithelial cell proliferation has been examined in this study. AGS cells were cultured with IL-1beta. DNA synthesis was assed by [3H]thymidine incorporation and total viable cell numbers by MTT assay. IL-1beta dose dependently increased DNA synthesis and cell numbers. The enhanced proliferation was blocked by interleukin-1 receptor antagonist. Addition of neutralising antibody to GM-CSF reduced IL-1beta-stimulated proliferation by 31 +/- 4 %. GM-CSF alone significantly stimulated proliferation. Addition or neutralisation of IL-8 had no effect on basal or IL-1beta-stimulated proliferation. The tyrosine kinase inhibitor genistein completely blocked IL-1beta-stimulated proliferation and inhibition of the extracellular signal related kinase pathway with PD 98059 inhibited IL-1beta stimulated proliferation by 58 +/- 5 %. IL-1beta stimulates proliferation in gastric epithelial cells. Autocrine stimulation by GM-CSF contributes to this proliferative response. Signalling via tyrosine kinase activity is essential to the mitogenic response to IL-1beta. The extracellular signal related kinase pathway is involved in, but not essential to downstream signalling. IL-1beta may contribute to the hyperproliferation seen in H. pylori- infected gastric mucosa, and be involved in the carcinogenic process.

Islets of Langerhans in the parakeet, Psittacula krameri.

PubMed

Gupta, Y K; Kumar, S

1980-01-01

The pancreatic gland of Psittacula krameri is divisible into 4 lobes i.e. dorsal, ventral, third and splenic. The endocrine part is composed of alpha 1-, alpha 2- and beta-cells. The islets are of 4 kinds viz., alpha islets (having alpha 1- and alpha 2-cells), beta islets (having beta- and alpha 1-cells), pure beta islets (consisting of beta-cells exclusively) and mixed islets (with beta-, alpha 1- and alpha 2-cells). The distribution of alpha islets is mostly restricted to the splenic and third lobes whereas the beta islets are found in all 4 lobes. Though the alpha islets are only few in the dorsal lobe, their size is best developed in the third and dorsal lobes. Sometimes beta and alpha islets are present in very close proximity but their cells never mingle. An interesting feature was the complete absence of alpha islets from the ventral lobe.A relative abundance of alpha 2- cells in this bird seems to be associated with its comparatively higher blood glucose level and frugivorous habit. Tinctorial reactions suggest that the insulin content of the endocrine pancreas is low. There were no seasonal changes in the islet tissue of P. krameri.

Stimulation of interleukin-1 beta production of human dental pulp cells by Porphyromonas endodontalis lipopolysaccharide.

PubMed

Hosoya, S; Matsushima, K

1997-01-01

IL-1 beta is synthesized as an inactive precursor, which is subsequently processed by IL-1 beta converting enzyme (ICE) and found extracellularly as a mature biologically active polypeptide. Also, IL-1 beta has been detected in necrotic and inflamed dental pulp. We examined the IL-1 beta production in human dental pulp (HDP) cells treated with lipopolysaccharide (LPS) from Porphyromonas endodontalis (P. e.) isolated from root canals and radicular cyst fluids. We demonstrated that P. e. LPS stimulated IL-1 beta release from HDP cells in a time- and dose-dependent manner. However, ICE activity was not increased by P. e. LPS. Northern blot hybridization analysis revealed that the IL-1 beta mRNA level in HDP cells was increased by P. e. LPS. These results suggest that stimulation of IL-1 beta release from HDP cells by P. e. LPS may have an important role in the progression of inflammation in pulpal and periapical disease.

Impaired compensatory beta-cell function and growth in response to high-fat diet in LDL receptor knockout mice

PubMed Central

Oliveira, Ricardo B d; Carvalho, Carolina P d F; Polo, Carla C; Dorighello, Gabriel d G; Boschero, Antônio C; Oliveira, Helena C F d; Collares-Buzato, Carla B

2014-01-01

In this study, we investigated the effect of low density lipoprotein receptor (LDLr) deficiency on gap junctional connexin 36 (Cx36) islet content and on the functional and growth response of pancreatic beta-cells in C57BL/6 mice fed a high-fat (HF) diet. After 60 days on regular or HF diet, the metabolic state and morphometric islet parameters of wild-type (WT) and LDLr−/− mice were assessed. HF diet-fed WT animals became obese and hypercholesterolaemic as well as hyperglycaemic, hyperinsulinaemic, glucose intolerant and insulin resistant, characterizing them as prediabetic. Also they showed a significant decrease in beta-cell secretory response to glucose. Overall, LDLr−/− mice displayed greater susceptibility to HF diet as judged by their marked cholesterolaemia, intolerance to glucose and pronounced decrease in glucose-stimulated insulin secretion. HF diet induced similarly in WT and LDLr−/− mice, a significant decrease in Cx36 beta-cell content as revealed by immunoblotting. Prediabetic WT mice displayed marked increase in beta-cell mass mainly due to beta-cell hypertrophy/replication. Nevertheless, HF diet-fed LDLr−/− mice showed no significant changes in beta-cell mass, but lower islet–duct association (neogenesis) and higher beta-cell apoptosis index were seen as compared to controls. The higher metabolic susceptibility to HF diet of LDLr−/− mice may be explained by a deficiency in insulin secretory response to glucose associated with lack of compensatory beta-cell expansion. PMID:24853046

Low intensity shear stress increases endothelial ELR+ CXC chemokine production via a focal adhesion kinase-p38{beta} MAPK-NF-{kappa}B pathway.

PubMed

Shaik, Sadiq S; Soltau, Thomas D; Chaturvedi, Gaurav; Totapally, Balagangadhar; Hagood, James S; Andrews, William W; Athar, Mohammad; Voitenok, Nikolai N; Killingsworth, Cheryl R; Patel, Rakesh P; Fallon, Michael B; Maheshwari, Akhil

2009-02-27

CXC chemokines with a glutamate-leucine-arginine (ELR) tripeptide motif (ELR(+) CXC chemokines) play an important role in leukocyte trafficking into the tissues. For reasons that are not well elucidated, circulating leukocytes are recruited into the tissues mainly in small vessels such as capillaries and venules. Because ELR(+) CXC chemokines are important mediators of endothelial-leukocyte interaction, we compared chemokine expression by microvascular and aortic endothelium to investigate whether differences in chemokine expression by various endothelial types could, at least partially, explain the microvascular localization of endothelial-leukocyte interaction. Both in vitro and in vivo models indicate that ELR(+) CXC chemokine expression is higher in microvascular endothelium than in aortic endothelial cells. These differences can be explained on the basis of the preferential activation of endothelial chemokine production by low intensity shear stress. Low shear activated endothelial ELR(+) CXC chemokine production via cell surface heparan sulfates, beta(3)-integrins, focal adhesion kinase, the mitogen-activated protein kinase p38beta, mitogen- and stress-associated protein kinase-1, and the transcription factor.

High LET Radiation Can Enhance TGF(Beta) Induced EMT and Cross-Talk with ATM Pathways

NASA Technical Reports Server (NTRS)

Wang, Minli; Hada, Megumi; Huff, Janice; Pluth, Janice M.; Anderson, Janniffer; ONeill, Peter; Cucinotta, Francis A.

2010-01-01

The TGF(Beta) pathway has been shown to regulate or directly interact with the ATM pathway in the response to radiation in mammary epithelial cells. We investigated possible interactions between the TGF(Beta) and ATM pathways following simulated space radiation using hTERT immortalized human esophageal epithelial cells (EPC-hTERT), mink lung epithelial cells (Mv1lu), and several human fibroblast cell lines. TGF(Beta) is a key modulator of the Epithelial-Mesenchymal Transition (EMT), important in cancer progression and metastasis. The implication of EMT by radiation also has several lines of developing evidence, however is poorly understood. The identification of TGF(Beta) induced EMT can be shown in changes to morphology, related gene over expression or down regulation, which can be detected by RT-PCR, and immunostaining and western blotting. In this study, we have observed morphologic and molecular alternations consistent with EMT after Mv1lu cells were treated with TGF(Beta) High LET radiation enhanced TGF(Beta) mediated EMT with a dose as low as 0.1Gy. In order to consider the TGF(Beta) interaction with ATM we used a potent ATM inhibitor Ku55933 and investigated gene expression changes and Smad signaling kinetics. Ku559933 was observed to reverse TGF(Beta) induced EMT, while this was not observed in dual treated cells (radiation+TGF(Beta)). In EPC-hTERT cells, TGF(Beta) alone was not able to induce EMT after 3 days of application. A combined treatment with high LET, however, significantly caused the alteration of EMT markers. To study the function of p53 in the process of EMT, we knocked down P53 through RNA interference. Morphology changes associated with EMT were observed in epithelial cells with silenced p53. Our study indicates: high LET radiation can enhance TGF(Beta) induced EMT; while ATM is triggering the process of TGF(Beta)-induced EMT, p53 might be an essential repressor for EMT phenotypes.

Expression of the leukemia-associated CBF{beta}/SMMHC chimeric gene causes transformation of 3T3 cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hajra, A.; Liu, P.; Collins, E.S.

1994-09-01

A pericentric inversion of chromosome 16 (inv(16)(p13;q22)) is consistently seen in acute myeloid leukemia of the M4Eo subtype. This inversion fuses almost the entire coding region of the gene encoding of the {beta} subunit of the heterodimeric transcription factor CBF/PEBP2 to the region of the MYH11 gene encoding the rod domain for the smooth muscle myosin heavy chain (SMMHC). To investigate the biological properties of the CBF{beta}/SMMHC fusion protein, we have generated 3T3 cell lines that stably express the CBF{beta}/SMMHC chimeric cDNA or the normal, nonchimeric CBF{beta} and SMMHC cDNAs. 3T3 cells expressing CBF{beta}/SMMHC acquire a transformed phenotype, as indicatedmore » by altered cell morphology, formation of foci, and growth in soft agar. Cells constitutively overexpressing the normal CBF{beta} cDNA or the rod region of SMMHC remain nontransformed. Western blot analysis using antibodies to CBF{beta} and the SMMHC rod demonstrates that stably transfected cells express the appropriate chimeric or normal protein. Electrophoretic mobility shift assays reveal that cells transformed by the chimeric cDNA do not have a CBF-DNA complex of the expected mobility, but instead contain a large complex with CBF DNA-binding activity that fails to migrate out of the gel wells. In order to define the regions of CBF{beta}/SMMHC necessary for 3T3 transformation, we have stably transfected cells with mutant CBF{beta}/SMMHC cDNAs containing various deletions of the coding region. Analysis of these cell lines indicates that the transformation property of CBF{beta}/SMMHC requires regions of CBF{beta} known to be necessary for association with the DNA-binding CBF{alpha} subunit, and also requires an intact SMMHC carboxyl terminus, which is necessary for formation of the coiled coil domain of the myosin rod.« less

Expression of transforming growth factor-beta1, -beta2 and -beta3 in normal and diseased canine mitral valves.

PubMed

Aupperle, H; März, I; Thielebein, J; Schoon, H-A

2008-01-01

The pathogenesis of chronic valvular disease (CVD) in dogs remains unclear, but activation and proliferation of valvular stromal cells (VSC) and their transdifferentiation into myofibroblast-like cells has been described. These alterations may be influenced by transforming growth factor-beta (TGF-beta), a cytokine involved in extracellular matrix (ECM) regulation and mesenchymal cell differentiation. The present study investigates immunohistochemically the expression of TGF-beta1, -beta2, -beta3 and smooth muscle alpha actin (alpha-SMA) in normal canine mitral valves (MVs) (n=10) and in the valves of dogs with mild (n=7), moderate (n=14) and severe (n=9) CVD. In normal mitral valves there was no expression of alpha-SMA but VSC displayed variable expression of TGF-beta1 (10% of VSC labelled), TGF-beta2 (1-5% labelled) and TGF-beta3 (50% labelled). In mild CVD the affected atrialis contain activated and proliferating alpha-SMA-positive VSC, which strongly expressed TGF-beta1 and -beta3, but only 10% of these cells expressed TGF-beta2. In unaffected areas of the leaflet there was selective increase in expression of TGF-beta1 and -beta3. In advanced CVD the activated subendothelial VSC strongly expressed alpha-SMA, TGF-beta1 and -beta3. Inactive VSC within the centre of the nodules had much less labelling for TGF-beta1 and -beta3. TGF-beta1 labelling was strong within the ECM. These data suggest that TGF-beta plays a role in the pathogenesis of CVD by inducing myofibroblast-like differentiation of VSC and ECM secretion. Changed haemodynamic forces and expression of matrix metalloproteinases (MMPs) may in turn regulate TGF-beta expression.

{beta}-Catenin regulates airway smooth muscle contraction.

PubMed

Jansen, Sepp R; Van Ziel, Anna M; Baarsma, Hoeke A; Gosens, Reinoud

2010-08-01

beta-Catenin is an 88-kDa member of the armadillo family of proteins that is associated with the cadherin-catenin complex in the plasma membrane. This complex interacts dynamically with the actin cytoskeleton to stabilize adherens junctions, which play a central role in force transmission by smooth muscle cells. Therefore, in the present study, we hypothesized a role for beta-catenin in the regulation of smooth muscle force production. beta-Catenin colocalized with smooth muscle alpha-actin (sm-alpha-actin) and N-cadherin in plasma membrane fractions and coimmunoprecipitated with sm-alpha-actin and N-cadherin in lysates of bovine tracheal smooth muscle (BTSM) strips. Moreover, immunocytochemistry of cultured BTSM cells revealed clear and specific colocalization of sm-alpha-actin and beta-catenin at the sites of cell-cell contact. Treatment of BTSM strips with the pharmacological beta-catenin/T cell factor-4 (TCF4) inhibitor PKF115-584 (100 nM) reduced beta-catenin expression in BTSM whole tissue lysates and in plasma membrane fractions and reduced maximal KCl- and methacholine-induced force production. These changes in force production were not accompanied by changes in the expression of sm-alpha-actin or sm-myosin heavy chain (MHC). Likewise, small interfering RNA (siRNA) knockdown of beta-catenin in BTSM strips reduced beta-catenin expression and attenuated maximal KCl- and methacholine-induced contractions without affecting sm-alpha-actin or sm-MHC expression. Conversely, pharmacological (SB-216763, LiCl) or insulin-induced inhibition of glycogen synthase kinase-3 (GSK-3) enhanced the expression of beta-catenin and augmented maximal KCl- and methacholine-induced contractions. We conclude that beta-catenin is a plasma membrane-associated protein in airway smooth muscle that regulates active tension development, presumably by stabilizing cell-cell contacts and thereby supporting force transmission between neighboring cells.

Evaluation of suitable porosity for sintered porous {beta}-tricalcium phosphate as a bone substitute

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Jin-Hong; Bae, Ji-Yong; Shim, Jaebum

2012-09-15

Structural and mechanical characterization is performed for sintered porous beta tricalcium phosphate ({beta}-TCP) to determine the appropriate porosity for use as a bone substitute. Four different types of porous {beta}-TCP specimen with different porosities are fabricated through a sintering process. For structural characterization, scanning electron microscopy and a Microfocus X-ray computed tomography system are used to investigate the pore openings on the specimen's surface, pore size, pore distribution, and pore interconnections. Compression tests of the specimens are performed, and mechanical properties such as the elastic modulus and compressive strength are obtained. Also, the geometric shape and volume of the {beta}-TCPmore » around the contact region of two pores, which need to be initially resolved after implantation in order to increase the size of the pore openings, are evaluated through simple calculations. The results show that porous {beta}-TCP with 42.1% porosity may be a suitable bone substitute candidate in terms of sustaining external loads, and inducing and cultivating bone cells. - Highlights: Black-Right-Pointing-Pointer Structural and mechanical characterization was performed for sintered porous {beta}-TCP specimens. Black-Right-Pointing-Pointer For structural characterization, SEM and Microfocus X-ray CT system were used. Black-Right-Pointing-Pointer For mechanical characterization, compression tests were performed. Black-Right-Pointing-Pointer Porous {beta}-TCP with 42.1% porosity may be a suitable bone substitute.« less

TGF-beta1 stimulates expression of the aromatase (CYP19) gene in human osteoblast-like cells and THP-1 cells.

PubMed

Shozu, M; Zhao, Y; Simpson, E R

2000-02-25

Recent evidence has shown that bone is not only a target of estrogen action but also a source of local estrogen production. Bone cells such as osteoblasts express aromatase (P450arom) and the expression of P450arom in osteoblasts is positively regulated in a tissue specific fashion, as in the case of other tissues which express P450arom. To clarify the physiological factors regulating expression of P450arom in bone, we tested TGF-beta1 using osteoblast-like cells obtained from human fetuses as well as THP-1 cells. TGF-beta1 increased IL-1beta+DEX- induced aromatase activity in osteoblast-like cells, while it inhibited activity in skin fibroblasts. Similar enhancement of aromatase activity by TGF-beta1 was found in DEX-stimulated THP-1 cells and this cell line was used for further experiments. In THP-1 cells, TGF-beta1 enhanced DEX-induced aromatase activity almost linearly by 12 h and thereafter. Increased levels of P450arom transcripts were also demonstrated by RT-PCR at 3 h of TGF-beta1 treatment and thereafter. Cyclohexamide abolished enhancement of activity but did not inhibit the accumulation of P450arom transcripts induced by TGF-beta1. Increase in P450arom expression by TGF-beta1 was attributable to expression driven by promoter I.4. TGF-beta1 did not change the half life of P450arom transcripts. To identify the cis-acting elements responsible for TGF-beta1 action on aromatase expression, transient transfection assays were performed using a series of deletion constructs for promoter I.4 (P450-I.4/Luc). Two constructs (-410/+14 and-340/+14) that contain a functional glucocorticoid response element (GRE) and downstream sequence showed significant increase of luciferase activity in response to TGF-beta1. Deletion and mutation of the GRE in P450-I.4/Luc (-340/+14) abolished the TGF-beta1. The luciferase activity of a (GRE)(1)-SV40/Luc construct was also stimulated by TGF-beta1. These results indicate that TGF-beta1 increases the expression of P450arom at the level of transcription through promoter I.4, at least in part via an enhancement of transactivation activity of the GR in THP-1 cells. TGF-beta1 is suggested to be one of the physiological up-regulatory factors of bone aromatase.

Beta-lactam antibiotics modulate T-cell functions and gene expression via covalent binding to cellular albumin.

PubMed

Mor, Felix; Cohen, Irun R

2013-02-19

Recent work has suggested that beta-lactam antibiotics might directly affect eukaryotic cellular functions. Here, we studied the effects of commonly used beta-lactam antibiotics on rodent and human T cells in vitro and in vivo on T-cell-mediated experimental autoimmune diseases. We now report that experimental autoimmune encephalomyelitis and adjuvant arthritis were significantly more severe in rats treated with cefuroxime and other beta-lactams. T cells appeared to mediate the effect: an anti-myelin basic protein T-cell line treated with cefuroxime or penicillin was more encephalitogenic in adoptive transfer experiments. The beta-lactam ampicillin, in contrast to cefuroxime and penicillin, did not enhance encephalomyelitis, but did inhibit the autoimmune diabetes developing spontaneously in nonobese diabetic mice. Gene expression analysis of human peripheral blood T cells showed that numerous genes associated with T helper 2 (Th2) and T regulatory (Treg) differentiation were down-regulated in T cells stimulated in the presence of cefuroxime; these genes were up-regulated in the presence of ampicillin. The T-cell protein that covalently bound beta-lactam antibiotics was found to be albumin. Human and rodent T cells expressed albumin mRNA and protein, and penicillin-modified albumin was taken up by rat T cells, leading to enhanced encephalitogenicity. Thus, beta-lactam antibiotics in wide clinical use have marked effects on T-cell behavior; beta-lactam antibiotics can function as immunomodulators, apparently through covalent binding to albumin.

Effect of beta-carotene-rich tomato lycopene beta-cyclase ( tlcy-b) on cell growth inhibition in HT-29 colon adenocarcinoma cells.

PubMed

Palozza, Paola; Bellovino, Diana; Simone, Rossella; Boninsegna, Alma; Cellini, Francesco; Monastra, Giovanni; Gaetani, Sancia

2009-07-01

Lycopene beta-cyclase (tlcy-b) tomatoes, obtained by modulating carotenogenesis via genetic engineering, contain a large amount of beta-carotene, as clearly visible by their intense orange colour. In the present study we have subjected tlcy-b tomatoes to an in vitro simulated digestion and analysed the effects of digestate on cell proliferation. To this aim we used HT-29 human colon adenocarcinoma cells, grown in monolayers, as a model. Digested tomatoes were diluted (20 ml, 50 ml and 100 ml/l) in culture medium and added to the cells for different incubation times (24 h, 48 h and 72 h). Inhibition of cell growth by tomato digestate was dose-dependent and resulted from an arrest of cell cycle progression at the G0/G1 and G2/M phase and by apoptosis induction. A down-regulation of cyclin D1, Bcl-2 and Bcl-xl expression was observed. We also found that heat treatment of samples before digestion enhanced beta-carotene release and therefore cell growth inhibition. To induce with purified beta-carotene solubilised in tetrahydrofuran the same cell growth inhibition obtained with the tomato digestate, a higher amount of the carotenoid was necessary, suggesting that beta-carotene micellarised during digestion is utilised more efficiently by the cells, but also that other tomato molecules, reasonably made available during digestion, may be present and cooperate with beta-carotene in promoting cell growth arrest.

Insulin-producing cells could not mimic the physiological regulation of insulin secretion performed by pancreatic beta cells

PubMed Central

2013-01-01

Objective The aim of this study was to compare the difference between insulin-producing cells (IPCs) and normal human pancreatic beta cells both in physiological function and morphological features in cellular level. Methods The levels of insulin secretion were measured by enzyme-linked immunosorbent assay. The insulin gene expression was determined by real-time quantitative polymerase chain reaction. The morphological features were detected by atomic force microscopy (AFM) and laser confocal scanning microscopy. Results IPCs and normal human pancreatic beta cells were similar to each other under the observation in AFM with the porous structure features in the cytoplasm. Both number of membrane particle size and average roughness of normal human beta cells were higher than those of IPCs. Conclusions Our results firstly revealed that the cellular ultrastructure of IPCs was closer to that of normal human pancreatic beta cells, but they still could not mimic the physiological regulation of insulin secretion performed by pancreatic beta cells. PMID:23421382

Toward beta cell replacement for diabetes

PubMed Central

Johannesson, Bjarki; Sui, Lina; Freytes, Donald O; Creusot, Remi J; Egli, Dieter

2015-01-01

The discovery of insulin more than 90 years ago introduced a life-saving treatment for patients with type 1 diabetes, and since then, significant progress has been made in clinical care for all forms of diabetes. However, no method of insulin delivery matches the ability of the human pancreas to reliably and automatically maintain glucose levels within a tight range. Transplantation of human islets or of an intact pancreas can in principle cure diabetes, but this approach is generally reserved for cases with simultaneous transplantation of a kidney, where immunosuppression is already a requirement. Recent advances in cell reprogramming and beta cell differentiation now allow the generation of personalized stem cells, providing an unlimited source of beta cells for research and for developing autologous cell therapies. In this review, we will discuss the utility of stem cell-derived beta cells to investigate the mechanisms of beta cell failure in diabetes, and the challenges to develop beta cell replacement therapies. These challenges include appropriate quality controls of the cells being used, the ability to generate beta cell grafts of stable cellular composition, and in the case of type 1 diabetes, protecting implanted cells from autoimmune destruction without compromising other aspects of the immune system or the functionality of the graft. Such novel treatments will need to match or exceed the relative safety and efficacy of available care for diabetes. PMID:25733347

PDGF-regulated rab4-dependent recycling of alphavbeta3 integrin from early endosomes is necessary for cell adhesion and spreading.

PubMed

Roberts, M; Barry, S; Woods, A; van der Sluijs, P; Norman, J

2001-09-18

It has been postulated that the regulation of integrin vesicular traffic facilitates cell migration by internalizing integrins at the rear of the cell and transporting them forward within vesicles for exocytosis at the leading edge to form new contacts with the extracellular matrix. The rab family of GTPases control key targeting events in the endo/exocytic pathway; therefore, these GTPases may be involved in the regulation of cell-matrix contact assembly. The endo/exocytic cycle of alphavbeta3 and alpha5beta1 integrins was studied using mouse 3T3 fibroblast cell lines. In serum-starved cells, internalized integrins were transported through rab4-positive, early endosomes and arrived at the rab11-positive, perinuclear recycling compartment approximately 30 min after endocytosis. From the recycling compartment, integrins were recycled to the plasma membrane in a rab11-dependent fashion. Following treatment with PDGF, alphavbeta3 integrin, but not alpha5beta1, was rapidly recycled directly back to the plasma membrane from the early endosomes via a rab4-dependent mechanism without the involvement of rab11. This rapid recycling pathway directed alphavbeta3 to numerous small puncta distributed evenly across the dorsal surface of the cell, and the integrin only became localized into focal complexes at later times following PDGF addition. Interestingly, inhibition of PDGF-stimulated alphavbeta3 recycling using dominant-negative rab4 mutants compromised cell adhesion and spreading on vitronectin (a ligand for alphavbeta3), but adhesion to fibronectin (a ligand for alpha5beta1 and alphavbeta3) was unchanged. We propose that growth factor-regulated, rab4-dependent recycling of alphavbeta3 integrin from early endosomes to the plasma membrane is a critical upstream event in the assembly of cell-matrix contacts.

The ectopic expression of Pax4 in the mouse pancreas converts progenitor cells into alpha and subsequently beta cells.

PubMed

Collombat, Patrick; Xu, Xiaobo; Ravassard, Philippe; Sosa-Pineda, Beatriz; Dussaud, Sébastien; Billestrup, Nils; Madsen, Ole D; Serup, Palle; Heimberg, Harry; Mansouri, Ahmed

2009-08-07

We have previously reported that the loss of Arx and/or Pax4 gene activity leads to a shift in the fate of the different endocrine cell subtypes in the mouse pancreas, without affecting the total endocrine cell numbers. Here, we conditionally and ectopically express Pax4 using different cell-specific promoters and demonstrate that Pax4 forces endocrine precursor cells, as well as mature alpha cells, to adopt a beta cell destiny. This results in a glucagon deficiency that provokes a compensatory and continuous glucagon+ cell neogenesis requiring the re-expression of the proendocrine gene Ngn3. However, the newly formed alpha cells fail to correct the hypoglucagonemia since they subsequently acquire a beta cell phenotype upon Pax4 ectopic expression. Notably, this cycle of neogenesis and redifferentiation caused by ectopic expression of Pax4 in alpha cells is capable of restoring a functional beta cell mass and curing diabetes in animals that have been chemically depleted of beta cells.

Genome-wide analysis of DNA methylation variations caused by chronic glucolipotoxicity in beta-cells.

PubMed

Hu, Y; Xu, X-H; He, K; Zhang, L-L; Wang, S-K; Pan, Y-Q; He, B-S; Feng, T-T; Mao, X-M

2014-02-01

There is a growing body of literature suggesting the role of interactions between genes and the environment in development of type 2 diabetes mellitus (T2DM). However, the interplay between environment and genetic in developing and progressing T2MD is not fully understood. To determine the effects of high-glucose-lipid on the status of DNA methylation in beta cells, and clarify the mechanism of glucolipotoxicity on beta-cell deterioration, the DNA methylation profile was detected in beta-cells cultured with high-glucose-lipid medium.We utilized a high throughput NimbleGen RN34 CpG Island & Promoter Microarray to investigate the DNA methylation profile in beta-cells cultured with high-glucose-lipid medium. To validate the results of microarray, the immunoprecipitation (MeDIP) PCR was used to test the methylation status of some selected genes. The mRNA and protein expression of insulin and Tcf7l2 in these cells were quantified by RT-PCR and western blot, respectively.We have identified a lot of loci which experienced aberrant DNA methylation in beta-cells cultured with high-glucose-lipid medium. The results of MeDIP PCR were consistency to the microarray. An opposite regulation in transcription and translation of Tcf7l2 gene was found. Furthermore, the insulin mRNA and protein expression in beta-cells also decreased after cultured with high-glucose-lipid medium compared with the control cells.We conclude that chronic glucolipotoxicity could induce aberrant DNA methylation of some genes and may affect these genes expression in beta-cells, which might contribute to beta-cell function failure in T2DM and be helpful to explain, at least partially, the mechanism of glucolipotoxicity on beta-cells deterioration. © J. A. Barth Verlag in Georg Thieme Verlag KG Stuttgart · New York.

Novel function of STAT1beta in B cells: induction of cell death by a mechanism different from that of STAT1alpha.

PubMed

Najjar, Imen; Schischmanoff, Pierre Olivier; Baran-Marszak, Fanny; Deglesne, Pierre-Antoine; Youlyouz-Marfak, Ibtissam; Pampin, Mathieu; Feuillard, Jean; Bornkamm, Georg W; Chelbi-Alix, Mounira K; Fagard, Remi

2008-12-01

Alternate splicing of STAT1 produces two isoforms: alpha, known as the active form, and beta, previously shown to act as a dominant-negative factor. Most studies have dealt with STAT1alpha, showing its involvement in cell growth control and cell death. To examine the specific function of either isoform in cell death, a naturally STAT1-deficient human B cell line was transfected to express STAT1alpha or STAT1beta. STAT1alpha, expressed alone, enhanced cell death, potentiated the fludarabine-induced apoptosis, and enhanced the nuclear location, the phosphorylation, and the transcriptional activity of p53. Unexpectedly, STAT1beta, expressed alone, induced cell death through a mechanism that was independent of the nuclear function of p53. Indeed, in STAT1beta-expressing B cells, p53 was strictly cytoplasmic where it formed clusters, and there was no induction of the transcriptional activity of p53. These data reveal a novel role of STAT1beta in programmed cell death, which is independent of p53.

Genetics Home Reference: sickle cell disease

MedlinePlus

... of beta-globin; this abnormality is called beta thalassemia . In people with sickle cell disease , at least ... globin. If mutations that produce hemoglobin S and beta thalassemia occur together, individuals have hemoglobin S- beta thalassemia (HbSBetaThal) ...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Jiying; Ohno-Matsui, Kyoko, E-mail: k.ohno.oph@tmd.ac.jp; Morita, Ikuo

Highlights: Black-Right-Pointing-Pointer Cholesterol-treated RPE produces more A{beta} than non-treated RPE. Black-Right-Pointing-Pointer Neprilysin expression and activity decreased in cholesterol-treated RPE. Black-Right-Pointing-Pointer {alpha}-Secretase expression and activity decreased in cholesterol-treated RPE. Black-Right-Pointing-Pointer Cholesterol-enriched diet induced subRPE deposits in aged mice. Black-Right-Pointing-Pointer A{beta} were present in cholesterol-enriched-diet-induced subRPE deposits in aged mice. -- Abstract: Subretinally-deposited amyloid {beta} (A{beta}) is a main contributor of developing age-related macular degeneration (AMD). However, the mechanism causing A{beta} deposition in AMD eyes is unknown. Hypercholesterolemia is a significant risk for developing AMD. Thus, we investigated the effects of cholesterol on A{beta} production in retinal pigment epithelial (RPE) cells inmore » vitro and in the mouse retina in vivo. RPE cells isolated from senescent (12-month-old) C57BL/6 mice were treated with 10 {mu}g/ml cholesterol for 48 h. A{beta} amounts in culture supernatants were measured by ELISA. Activity and expression of enzymes and proteins that regulate A{beta} production were examined by activity assay and real time PCR. The retina of mice fed cholesterol-enriched diet was examined by transmission electron microscopy. Cholesterol significantly increased A{beta} production in cultured RPE cells. Activities of A{beta} degradation enzyme; neprilysin (NEP) and anti-amyloidogenic secretase; {alpha}-secretase were significantly decreased in cell lysates of cholesterol-treated RPE cells compared to non-treated cells, but there was no change in the activities of {beta}- or {gamma}-secretase. mRNA levels of NEP and {alpha}-secretase (ADAM10 and ADAM17) were significantly lower in cholesterol-treated RPE cells than non-treated cells. Senescent (12-month-old) mice fed cholesterol-enriched chow developed subRPE deposits containing A{beta}, whereas age-matched mice fed standard rodent chow diet did not. Activities and mRNA levels of NEP and {alpha}-secretase were significantly lower in native RPE cells freshly isolated from cholesterol-enriched chow fed mice compared to standard rodent chow fed mice. These findings suggest that cholesterol enhances subretinal A{beta} accumulation by modulating the activities of enzymes degrading and processing A{beta} in RPE cells in senescent subjects.« less

Discovery, SAR, and Radiolabeling of Halogenated Benzimidazole Carboxamide Antagonists as Useful Tools for (alpha)4(beta)1 Integrin Expressed on T- and B-cell Lymphomas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carpenter, R D; Natarajan, A; Lau, E Y

2010-02-08

The cell surface receptor {alpha}{sub 4}{beta}{sub 1} integrin is an attractive yet poorly understood target for selective diagnosis and treatment of T- and B-cell lymphomas. This report focuses on the rapid microwave preparation of medicinally pertinent benzimidazole heterocycles, structure-activity relationships (SAR) of novel halobenzimidazole carboxamide antagonists 3-6, and preliminary biological evaluation of radioiodinated agents 7, 8, and 18. The I-125 derivative 18 had good tumor uptake (12 {+-} 1% ID/g at 24 h; 4.5 {+-} 1% ID/g at 48 h) and tumor:kidney ratio ({approx}4:1 at 24 h; 2.5:1 at 48 h) in xenograft murine models of B-cell lymphoma. Molecular homologymore » models of {alpha}{sub 4}{beta}{sub 1} integrin have predicted that docked halobenzimidazole carboxamides have the halogen atom in a suitable orientation for halogen-hydrogen bonding. These high affinity ({approx} pM binding) halogenated ligands are attractive tools for medicinal and biological use; the fluoro and iodo derivatives are potential radiodiagnostic ({sup 18}F) or radiotherapeutic ({sup 131}I) agents, whereas the chloro and bromo analogues could provide structural insight into integrin-ligand interactions through photoaffinity cross-linking/mass spectroscopy experiments, as well as co-crystallization X-ray studies.« less

Beta2 toxin is not involved in in vitro cell cytotoxicity caused by human and porcine cpb2-harbouring Clostridium perfringens.

PubMed

Allaart, Janneke G; van Asten, Alphons J A M; Vernooij, Johannes C M; Gröne, Andrea

2014-06-25

Clostridium perfringens is a common cause of intestinal disease in animals and humans. Its pathogenicity is attributed to the toxins it can produce, including the beta2 toxin. The presence of cpb2, the gene encoding the beta2 toxin, has been associated with diarrhoea in neonatal piglets and humans. However, the exact role of the beta2 toxin in the development of diarrhoea is still unknown. In this study we investigated the level of cytotoxicity to porcine IPI-21 and human Caco-2 cell-lines caused by porcine and human cpb2-harbouring C. perfringens and the significance of the beta2 toxin for the induction of cell cytotoxicity. Supernatants of porcine cpb2-harbouring C. perfringens strains were cytotoxic to both cell lines. Cell cytotoxicity caused by supernatant of human cpb2-harbouring C. perfringens strains was variable among strains. However, removal of the beta2 toxin by anti-beta2 toxin antibodies or degradation of the beta2 toxin by trypsin did not reduce the cytotoxic effect of any of the supernatants. These data suggest that beta2 toxin does not play a role in the development of cell cytotoxicity in in vitro experiments. In vivo studies are necessary to definitely define the role of beta2 toxin in the development of cell cytotoxicity and subsequent diarrhoea. Copyright © 2014 Elsevier B.V. All rights reserved.

Cell cycle-related metabolism and mitochondrial dynamics in a replication-competent pancreatic beta-cell line.

PubMed

Montemurro, Chiara; Vadrevu, Suryakiran; Gurlo, Tatyana; Butler, Alexandra E; Vongbunyong, Kenny E; Petcherski, Anton; Shirihai, Orian S; Satin, Leslie S; Braas, Daniel; Butler, Peter C; Tudzarova, Slavica

2017-01-01

Cell replication is a fundamental attribute of growth and repair in multicellular organisms. Pancreatic beta-cells in adults rarely enter cell cycle, hindering the capacity for regeneration in diabetes. Efforts to drive beta-cells into cell cycle have so far largely focused on regulatory molecules such as cyclins and cyclin-dependent kinases (CDKs). Investigations in cancer biology have uncovered that adaptive changes in metabolism, the mitochondrial network, and cellular Ca 2+ are critical for permitting cells to progress through the cell cycle. Here, we investigated these parameters in the replication-competent beta-cell line INS 832/13. Cell cycle synchronization of this line permitted evaluation of cell metabolism, mitochondrial network, and cellular Ca 2+ compartmentalization at key cell cycle stages. The mitochondrial network is interconnected and filamentous at G1/S but fragments during the S and G2/M phases, presumably to permit sorting to daughter cells. Pyruvate anaplerosis peaks at G1/S, consistent with generation of biomass for daughter cells, whereas mitochondrial Ca 2+ and respiration increase during S and G2/M, consistent with increased energy requirements for DNA and lipid synthesis. This synchronization approach may be of value to investigators performing live cell imaging of Ca 2+ or mitochondrial dynamics commonly undertaken in INS cell lines because without synchrony widely disparate data from cell to cell would be expected depending on position within cell cycle. Our findings also offer insight into why replicating beta-cells are relatively nonfunctional secreting insulin in response to glucose. They also provide guidance on metabolic requirements of beta-cells for the transition through the cell cycle that may complement the efforts currently restricted to manipulating cell cycle to drive beta-cells through cell cycle.

Targeting Cellular Calcium Homeostasis to Prevent Cytokine-Mediated Beta Cell Death.

PubMed

Clark, Amy L; Kanekura, Kohsuke; Lavagnino, Zeno; Spears, Larry D; Abreu, Damien; Mahadevan, Jana; Yagi, Takuya; Semenkovich, Clay F; Piston, David W; Urano, Fumihiko

2017-07-17

Pro-inflammatory cytokines are important mediators of islet inflammation, leading to beta cell death in type 1 diabetes. Although alterations in both endoplasmic reticulum (ER) and cytosolic free calcium levels are known to play a role in cytokine-mediated beta cell death, there are currently no treatments targeting cellular calcium homeostasis to combat type 1 diabetes. Here we show that modulation of cellular calcium homeostasis can mitigate cytokine- and ER stress-mediated beta cell death. The calcium modulating compounds, dantrolene and sitagliptin, both prevent cytokine and ER stress-induced activation of the pro-apoptotic calcium-dependent enzyme, calpain, and partly suppress beta cell death in INS1E cells and human primary islets. These agents are also able to restore cytokine-mediated suppression of functional ER calcium release. In addition, sitagliptin preserves function of the ER calcium pump, sarco-endoplasmic reticulum Ca 2+ -ATPase (SERCA), and decreases levels of the pro-apoptotic protein thioredoxin-interacting protein (TXNIP). Supporting the role of TXNIP in cytokine-mediated cell death, knock down of TXNIP in INS1-E cells prevents cytokine-mediated beta cell death. Our findings demonstrate that modulation of dynamic cellular calcium homeostasis and TXNIP suppression present viable pharmacologic targets to prevent cytokine-mediated beta cell loss in diabetes.

Molecular basis for the regulation of islet beta cell mass in mice: the role of E-cadherin

PubMed Central

Wakae-Takada, N.; Xuan, S.; Watanabe, K.; Meda, P.; Leibel, R. L.

2014-01-01

Aims/hypothesis In rodents and humans, the rate of beta cell proliferation declines rapidly after birth; formation of the islets of Langerhans begins perinatally and continues after birth. Here, we tested the hypothesis that increasing levels of E-cadherin during islet formation mediate the decline in beta cell proliferation rate by contributing to a reduction of nuclear β-catenin and D-cyclins. Methods We examined E-cadherin, nuclear β-catenin, and D-cyclin levels, as well as cell proliferation during in vitro and in vivo formation of islet cell aggregates, using β-TC6 cells and transgenic mice with green fluorescent protein (GFP)-labelled beta cells, respectively. We tested the role of E-cadherin using antisense-mediated reductions of E-cadherin in β-TC6 cells, and mice segregating for a beta cell-specific E-cadherin knockout (Ecad [also known as Cdh1] βKO). Results In vitro, pseudo-islets of β-TC6 cells displayed increased E-cadherin but decreased nuclear β-catenin and cyclin D2, and reduced rates of cell proliferation, compared with monolayers. Antisense knockdown of E-cadherin increased cell proliferation and levels of cyclins D1 and D2. After birth, beta cells showed increased levels of E-cadherin, but decreased levels of D-cyclin, whereas islets of Ecad βKO mice showed increased levels of D-cyclins and nuclear β-catenin, as well as increased beta cell proliferation. These islets were significantly larger than those of control mice and displayed reduced levels of connexin 36. These changes correlated with reduced insulin response to ambient glucose, both in vitro and in vivo. Conclusions/interpretation The findings support our hypothesis by indicating an important role of E-cadherin in the control of beta cell mass and function. PMID:23354125

Molecular basis for the regulation of islet beta cell mass in mice: the role of E-cadherin.

PubMed

Wakae-Takada, N; Xuan, S; Watanabe, K; Meda, P; Leibel, R L

2013-04-01

In rodents and humans, the rate of beta cell proliferation declines rapidly after birth; formation of the islets of Langerhans begins perinatally and continues after birth. Here, we tested the hypothesis that increasing levels of E-cadherin during islet formation mediate the decline in beta cell proliferation rate by contributing to a reduction of nuclear β-catenin and D-cyclins. We examined E-cadherin, nuclear β-catenin, and D-cyclin levels, as well as cell proliferation during in vitro and in vivo formation of islet cell aggregates, using β-TC6 cells and transgenic mice with green fluorescent protein (GFP)-labelled beta cells, respectively. We tested the role of E-cadherin using antisense-mediated reductions of E-cadherin in β-TC6 cells, and mice segregating for a beta cell-specific E-cadherin knockout (Ecad [also known as Cdh1] βKO). In vitro, pseudo-islets of β-TC6 cells displayed increased E-cadherin but decreased nuclear β-catenin and cyclin D2, and reduced rates of cell proliferation, compared with monolayers. Antisense knockdown of E-cadherin increased cell proliferation and levels of cyclins D1 and D2. After birth, beta cells showed increased levels of E-cadherin, but decreased levels of D-cyclin, whereas islets of Ecad βKO mice showed increased levels of D-cyclins and nuclear β-catenin, as well as increased beta cell proliferation. These islets were significantly larger than those of control mice and displayed reduced levels of connexin 36. These changes correlated with reduced insulin response to ambient glucose, both in vitro and in vivo. The findings support our hypothesis by indicating an important role of E-cadherin in the control of beta cell mass and function.

Beta-catenin interacts with low-molecular-weight protein tyrosine phosphatase leading to cadherin-mediated cell-cell adhesion increase.

PubMed

Taddei, Maria Letizia; Chiarugi, Paola; Cirri, Paolo; Buricchi, Francesca; Fiaschi, Tania; Giannoni, Elisa; Talini, Doriana; Cozzi, Giacomo; Formigli, Lucia; Raugei, Giovanni; Ramponi, Giampietro

2002-11-15

Beta-catenin plays a dual role as a major constituent of cadherin-based adherens junctions and also as a transcriptional coactivator. In normal ephitelial cells, at adherens junction level, beta-catenin links cadherins to the actin cytoskeleton. The structure of adherens junctions is dynamically regulated by tyrosine phosphorylation. In particular, cell-cell adhesion can be negatively regulated through the tyrosine phosphorylation of beta-catenin. Furthermore, the loss of beta-catenin-cadherin association has been correlated with the transition from a benign tumor to an invasive, metastatic cancer. Low-molecular-weight protein tyrosine phosphatase (LMW-PTP) is a ubiquitous PTP implicated in the regulation of mitosis and cytoskeleton rearrangement. Here we demonstrate that the amount of free cytoplasmic beta-catenin is decreased in NIH3T3, which overexpresses active LMW-PTP, and this results in a stronger association between cadherin complexes and the actin-based cytoskeleton with respect to control cells. Confocal microscopy analysis shows that beta-catenin colocalizes with LMW-PTP at the plasma membrane. Furthermore, we provide evidence that beta-catenin is able to associate with LMW-PTP both in vitro and in vivo. Moreover, overexpression of active LMW-PTP strongly potentiates cadherin-mediated cell-cell adhesion, whereas a dominant-negative form of LMW-PTP induces the opposite phenotype, both in NIH3T3 and in MCF-7 carcinoma cells. On the basis of these results, we propose that the stability of cell-cell contacts at the adherens junction level is positively influenced by LMW-PTP expression, mainly because of the beta-catenin and LMW-PTP interaction at the plasma membrane level with consequent dephosphorylation.

[The effect of 18beta-glycyrrhetinic acid on gap junction among cerebral arteriolar smooth muscle cells in Wistar rat and spontaneously hypertensive rat].

PubMed

Chen, Xin-Yan; Si, Jun-Qiang; Li, Li; Zhao, Lei; Wei, Li-Li; Jiang, Xue-Wei; Ma, Ke-Tao

2013-05-01

This study compared Wistar rat with spontaneously hypertensive rat (SHR) on the electrophysiology and coupling force of the smooth muscle cells in the cerebral arteriolar segments and observe the influence of 18beta-glycyrrhetinic acid(18beta-GA) on the gap junctions between the arterial smooth muscle cells. The outer layer's connective tissue of the cerebral arteriolar segments was removed. Whole-cell patch clamp recordings were used to observe the 18beta-GA's impaction on the arteriolar segment membrane's input capacitance (C(input)), input conductance (G(input)) and input resistance (R(input)) of the smooth muscle cells. (1) The C(input) and G(input) of the SHR arteriolar segment smooth muscle cells was much higher than the Wistar rats, there was significant difference (P < 0.05). (2) 18beta-GA concentration-dependently reduced C(input) and G(input) (or increase R(input)) on smooth muscle cells in arteriolar segment. IC50 of 18beta-GA suppression's G(input) of the Wistar rat and SHR were 1.7 and 2.0 micromol/L respectively, there was not significant difference (P > 0.05). After application of 18beta-GA concentration > or = 100 micrmol/L, the C(input), G(input) and R(input) of the single smooth muscle cells was very close. Gap junctional coupling is enhanced in the SHR cerebral arterial smooth muscle cells. 18beta-GA concentration-dependent inhibits Wistar rat's and SHR cerebral arteriolar gap junctions between arterial smooth muscle cells. The inhibitory potency is similar between the two different rats. When 18beta-GA concentration is > or = 100 micromol/L, it can completely block gap junctions between arteriolar smooth muscle cells.

Proliferation of Estrogen Receptor alpha Positive Mammary Epithelial Cells is Restrained by TGFbeta1 in Adult Mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ewan, Kenneth B.R.; Oketch-Rabah, Hellen A.; Ravani, Shraddha A.

2005-03-03

Transforming growth factor {beta}1 (TGF{beta}1) is a potent inhibitor of mammary epithelial proliferation. In human breast, estrogen receptor {alpha} (ER{alpha}) cells rarely co-localize with markers of proliferation, but their increased frequency correlates with breast cancer risk. To determine whether TGF{beta}1 is necessary for the quiescence of ER{alpha}-positive population, we examined mouse mammary epithelial gland at estrus. Approximately 35% of cells showed TGF{beta}1 activation, which co-localized with nuclear receptor-phosphorylated Smad 2/3, indicating that TGF{beta} signaling is autocrine. Furthermore, nuclear Smad co-localized with nuclear ER{alpha}. To test whether TGF{beta} was functional, we examined genetically engineered mice with different levels of TGF{beta}1. ER{alpha}more » co-localization with markers of proliferation (i.e. Ki-67 or BrdU) at estrus was significantly increased in the mammary glands of Tgf{beta}1 C57/bl/129SV heterozygote mice. This relationship was maintained following pregnancy, but was absent at puberty. Conversely, mammary epithelial expression of constitutively active TGF{beta}1 via the MMTV promoter suppressed proliferation of ER{alpha} positive cells. Thus, TGF{beta}1 activation functionally restrains ER{alpha} positive cells from proliferating in adult mammary gland. Accordingly, we propose that TGF{beta}1 dysregulation may promote proliferation of ER{alpha} positive cells associated with breast cancer risk in humans.« less

Insulin regulates Presenilin 1 localization via PI3K/Akt signaling.

PubMed

Maesako, Masato; Uemura, Kengo; Kubota, Masakazu; Ando, Koichi; Kuzuya, Akira; Asada, Megumi; Kihara, Takeshi; Kinoshita, Ayae

2010-10-15

Recently, insulin signaling has been highlighted in the pathology of Alzheimer's disease (AD). Although the association between insulin signaling and Tau pathology has been investigated in several studies, the interaction between insulin signaling and Presenilin 1 (PS1), a key molecule of amyloid beta (Abeta) pathology, has not been elucidated so far. In this study, we demonstrated that insulin inhibited PS1 phosphorylation at serine residues (serine 353, 357) via phosphatidylinositol 3-kinase (PI3K)/Akt signal pathway and strengthened the trimeric complex of PS1/N-cadherin/beta-catenin, consequently relocalizing PS1 to the cell surface. Since our recent report suggests that PS1/N-cadherin/beta-catenin complex regulates Abeta production, it is likely that insulin signaling affects Abeta pathology by regulating PS1 localization. 2010 Elsevier Ireland Ltd. All rights reserved.

Effects of growth factors and glucosamine on porcine mandibular condylar cartilage cells and hyaline cartilage cells for tissue engineering applications.

PubMed

Wang, Limin; Detamore, Michael S

2009-01-01

Temporomandibular joint (TMJ) condylar cartilage is a distinct cartilage that has both fibrocartilaginous and hyaline-like character, with a thin proliferative zone that separates the fibrocartilaginous fibrous zone at the surface from the hyaline-like mature and hypertrophic zones below. In this study, we compared the effects of insulin-like growth factor-I (IGF-I), basic fibroblast growth factor (bFGF), transforming growth factor beta1 (TGF-beta1), and glucosamine sulphate on porcine TMJ condylar cartilage and ankle cartilage cells in monolayer culture. In general, TMJ condylar cartilage cells proliferated faster than ankle cartilage cells, while ankle cells produced significantly greater amounts of glycosaminoglycans (GAGs) and collagen than TMJ condylar cartilage cells. IGF-I and bFGF were potent stimulators of TMJ cell proliferation, while no signals statistically outperformed controls for ankle cell proliferation. IGF-I was the most effective signal for GAG production with ankle cells, and the most potent upregulator of collagen synthesis for both cell types. Glucosamine sulphate promoted cell proliferation and biosynthesis at specific concentrations and outperformed growth factors in certain instances. In conclusion, hyaline cartilage cells had lower cell numbers and superior biosynthesis compared to TMJ condylar cartilage cells, and we have found IGF-I at 100 ng/mL and glucosamine sulphate at 100 microg/mL to be the most effective signals for these cells under the prescribed conditions.

Co-culture of clonal beta cells with GLP-1 and glucagon-secreting cell line impacts on beta cell insulin secretion, proliferation and susceptibility to cytotoxins.

PubMed

Green, Alastair D; Vasu, Srividya; Moffett, R Charlotte; Flatt, Peter R

2016-06-01

We investigated the direct effects on insulin releasing MIN6 cells of chronic exposure to GLP-1, glucagon or a combination of both peptides secreted from GLUTag L-cell and αTC1.9 alpha-cell lines in co-culture. MIN6, GLUTag and αTC1.9 cell lines exhibited high cellular hormone content and release of insulin, GLP-1 and glucagon, respectively. Co-culture of MIN6 cells with GLUTag cells significantly increased cellular insulin content, beta-cell proliferation, insulin secretory responses to a range of established secretogogues and afforded protection against exposure cytotoxic concentrations of glucose, lipid, streptozotocin or cytokines. Benefits of co-culture of MIN6 cells with αTC1.9 alphacells were limited to enhanced beta-cell proliferation with marginal positive actions on both insulin secretion and cellular protection. In contrast, co-culture of MIN6 with GLUTag cells plus αTC1.9 cells, markedly enhanced both insulin secretory responses and protection against beta-cell toxins compared with co-culture with GLUTag cells alone. These data indicate important long-term effects of conjoint GLP-1 and glucagon exposure on beta-cell function. This illustrates the possible functional significance of alpha-cell GLP-1 production as well as direct beneficial effects of dual agonism at beta-cell GLP-1 and glucagon receptors. Copyright © 2016 Elsevier B.V. and Société française de biochimie et biologie Moléculaire (SFBBM). All rights reserved.

Visualization of astaxanthin localization in HT29 human colon adenocarcinoma cells by combined confocal resonance Raman and fluorescence microspectroscopy.

PubMed

Briviba, Karlis; Bornemann, Rainer; Lemmer, Ulrich

2006-11-01

Astaxanthin, a carotenoid found in plants and seafood, exhibits antiproliferative, antioxidant and anticarcinogenic properties. We show that astaxanthin delivered with tetrahydrofuran is effectively taken up by cultured colon adenocarcinoma cells and is localized mostly in the cytoplasm as detected by confocal resonance Raman and broad-band fluorescence microspectroscopy image analysis. Cells incubated with beta-carotene at the same concentration as astaxanthin (10 microM) showed about a 50-fold lower cellular amount of beta-carotene, as detected by HPLC. No detectable Raman signal of beta-carotene was found in cells, but a weak broad-band fluorescence signal of beta-carotene was observed. beta-Carotene, like astaxanthin, was localized mostly in the cytoplasm. The heterogeneity of astaxanthin and beta-carotene cellular distribution in cells of intestinal origin suggests that the possible defense against reactive molecules by carotenoids in these cells may also be heterogeneous.

Regulated binding of PTP1B-like phosphatase to N-cadherin: control of cadherin-mediated adhesion by dephosphorylation of beta-catenin

PubMed Central

1996-01-01

Cadherins are a family of cell-cell adhesion molecules which play a central role in controlling morphogenetic movements during development. Cadherin function is regulated by its association with the actin containing cytoskeleton, an association mediated by a complex of cytoplasmic proteins, the catenins: alpha, beta, and gamma. Phosphorylated tyrosine residues on beta-catenin are correlated with loss of cadherin function. Consistent with this, we find that only nontyrosine phosphorylated beta-catenin is associated with N-cadherin in E10 chick retina tissue. Moreover, we demonstrate that a PTP1B-like tyrosine phosphatase associates with N-cadherin and may function as a regulatory switch controlling cadherin function by dephosphorylating beta-catenin, thereby maintaining cells in an adhesion-competent state. The PTP1B-like phosphatase is itself tyrosine phosphorylated. Moreover, both direct binding experiments performed with phosphorylated and dephosphorylated molecules, and treatment of cells with tyrosine kinase inhibitors indicate that the interaction of the PTP1B-like phosphatase with N-cadherin depends on its tyrosine phosphorylation. Concomitant with the tyrosine kinase inhibitor-induced loss of the PTP1B-like phosphatase from its association with N-cadherin, phosphorylated tyrosine residues are retained on beta-catenin, the association of N- cadherin with the actin containing cytoskeleton is lost and N-cadherin- mediated cell adhesion is prevented. Tyrosine phosphatase inhibitors also result in the accumulation of phosphorylated tyrosine residues on beta-catenin, loss of the association of N-cadherin with the actin- containing cytoskeleton, and prevent N-cadherin mediated adhesion, presumably by directly blocking the function of the PTP1B-like phosphatase. We previously showed that the binding of two ligands to the cell surface N-acetylgalactosaminylphosphotransferase (GalNAcPTase), the monoclonal antibody 1B11 and a proteoglycan with a 250-kD core protein, results in the accumulation of phosphorylated tyrosine residues on beta-catenin, uncoupling of N-cadherin from its association with the actin containing cytoskeleton, and loss of N- cadherin function. We now report that binding of these ligands to the GalNAcPTase results in the absence of the PTP1B-like phosphatase from its association with N-cadherin as well as the loss of the tyrosine kinase and tyrosine phosphatase activities that otherwise co- precipitate with N-cadherin. Control antibodies and proteoglycans have no such effect. This effect is similar to that observed with tyrosine kinase inhibitors, suggesting that the GalNAcPTase/proteoglycan interaction inhibits a tyrosine kinase, thereby preventing the phosphorylation of the PTP1B-like phosphatase, and its association with N-cadherin. Taken together these data indicate that a PTP1B-like tyrosine phosphatase can regulate N-cadherin function through its ability to dephosphorylate beta-catenin and that the association of the phosphatase with N-cadherin is regulated via the interaction of the GalNAcPTase with its proteoglycan ligand. In this manner the GalNAcPTase-proteoglycan interaction may play a major role in morphogenetic cell and tissue interactions during development. PMID:8707857

Akt interacts directly with Smad3 to regulate the sensitivity to TGF-beta induced apoptosis.

PubMed

Conery, Andrew R; Cao, Yanna; Thompson, E Aubrey; Townsend, Courtney M; Ko, Tien C; Luo, Kunxin

2004-04-01

Transforming growth factor beta (TGF-beta) induces both apoptosis and cell-cycle arrest in some cell lines, but only growth arrest in others. It is not clear how this differential response to TGF-beta is specified. Smad proteins are critical mediators of TGF-beta signalling. After stimulation by TGF-beta, Smad2 and Smad3 become phosphorylated by the activated TGF-beta receptor kinases, oligomerize with Smad4, translocate to the nucleus and regulate the expression of TGF-beta target genes. Here we report that the sensitivity to TGF-beta induced apoptosis is regulated by crosstalk between the Akt/PKB serine/threonine kinase and Smad3 through a mechanism that is independent of Akt kinase activity. Akt interacts directly with unphosphorylated Smad3 to sequester it outside the nucleus, preventing its phosphorylation and nuclear translocation. This results in inhibition of Smad3-mediated transcription and apoptosis. Furthermore, the ratio of Smad3 to Akt correlates with the sensitivity of cells to TGF-beta induced apoptosis. Alteration of this ratio changes the apoptotic, but not the growth-inhibitory, responses of cells to TGF-beta. These findings identify an important determinant of sensitivity to TGF-beta-induced apoptosis that involves crosstalk between the TGF-beta and phosphatidylinositol-3-OH kinase (PI(3)K) pathways.

Regulation of GM-CSF-induced dendritic cell development by TGF-beta1 and co-developing macrophages.

PubMed

Yamaguchi, Y

1998-01-01

Using a culture system of bone marrow progenitor cells with GM-CSF and TGF-beta1, a study was performed to analyze the effect of TGF-beta1 on the development of dendritic cells (DC) and to elucidate the regulatory role of macrophages co-developing with dendritic cells. The results demonstrate that DC generated in the presence of TGF-beta1 were immature with respect to the expression of CD86, nonspecific esterase activity and cell shape. Such inhibitory effects of TGF-beta1 were dependent on FcR+ macrophages, which were depleted by panning. TGF-beta1 did not appear to inhibit the commitment of progenitor cells to the DC lineage. In addition, TGF-beta1 also acted directly on the intermediate stage of DC to prevent their over-maturation, which results in a preferential decrease in MHC class II, but not in CD86, in the presence of TNF-alpha. FcR+ suppressive macrophages were also shown to facilitate DC maturation when stimulated via FcR-mediated signals even in the presence of TGF-beta1. These results indicate that TGF-beta1 indirectly and directly regulate the development of DC and that co-developing macrophages have a regulatory role in DC maturation.

Can transforming growth factor-beta1 and retinoids modify the activity of estradiol and antiestrogens in MCF-7 breast cancer cells?.

PubMed

Czeczuga-Semeniuk, Ewa; Anchim, Tomasz; Dziecioł, Janusz; Dabrowska, Milena; Wołczyński, Sławomir

2004-01-01

Retinoic acid and transforming growth factor-beta (TGF-beta) affect differentiation, proliferation and carcinogenesis of epithelial cells. The effect of both compounds on the proliferation of cells of the hormone sensitive human breast cancer cell line (ER+) MCF-7 was assessed in the presence of estradiol and tamoxifen. The assay was based on [3H]thymidine incorporation and the proliferative activity of PCNA- and Ki 67-positive cells. The apoptotic index and expression of the Bcl-2 and p53 antigens in MCF-7 cells were also determined. Exogenous TGF-beta1 added to the cell culture showed antiproliferative activity within the concentration range of 0.003-30 ng/ml. Irrespective of TGF-beta1 concentrations, a marked reduction in the stimulatory action of estradiol (10(-9) and 10(-8) M) was observed whereas in combination with tamoxifen (10(-7) and 10(-6) M) only 30 ng/ml TGF-beta1 caused a statistically significant reduction to approximately 30% of the proliferative cells. In further experiments we examined the effect of exposure of breast cancer cells to retinoids in combination with TGF-beta1. The incorporation of [3H]thymidine into MCF-7 cells was inhibited to 52 +/- 19% (control =100%) by 3 ng/ml TGF-beta1, and this dose was used throughout. It was found that addition of TGF-beta1 and isotretinoin to the culture did not decrease proliferation, while TGF-beta1 and tretinoin at low concentrations (3 x 10(-8) and 3 x 10(-7) M) reduced the percentage of proliferating cells by approximately 30% (67+/-8% and 67+/-5%, P<0.05 compared to values in the tretinoin group). Both retinoids also led to a statistically significant decrease in the stimulatory effect of 10(-9) M estradiol, attenuated by TGF-beta1. In addition, the retinoids in combination with TGF-beta1 and tamoxifen (10(-6) M) caused a further reduction in the percentage of proliferating cells. Immunocytochemical analysis showed that all the examined compounds gave a statistically significant reduction in the percentage of cells with a positive reaction to PCNA and Ki 67 antigen. TGF-beta1, isotretinoin and tretinoin added to the culture resulted in the lowest percentage of PCNA positive cells. However, the lowest fraction of Ki 67 positive cells was observed after addition of isotretinoin. The obtained results also confirm the fact that the well-known regulatory proteins Bcl-2 and p53 play an important role in the regulation of apoptosis in the MCF-7 cell line, with lowered Bcl-2 expression accompanying easier apoptotic induction. The majority of the examined compounds act via the p53 pathway although some bypass this important proapoptotic factor.

Basics and applications of stem cells in the pancreas.

PubMed

Sekine, Keisuke; Taniguchi, Hideki

2012-11-01

Enormous efforts have been made to establish pancreatic stem/progenitor cells as a source for regenerative medicine for the treatment of diabetes mellitus. In recent years, it has been recognized that the self-renewal of beta cells is the dominant process involved in postnatal beta-cell regeneration and expansion. Nevertheless, several in-vitro studies have suggested that ductal or as yet unidentified cells are candidates for pancreatic stem/progenitor cells that can differentiate into multilineage cells, including insulin(+) cells. The question remains as to whether beta cells are generated postnatally from stem/progenitor cells other than pre-existing beta cells. Furthermore, mutated pancreatic stem cells are considered to be prospective candidates for cancer stem cells or tumor-initiating cells. This review highlights recent progress in pancreatic stem/progenitor cell research.

Influence of local anesthetics upon human polymorphonuclear leukocyte function in vitro. Reduction of lysosomal enzyme release and superoxide anion production

PubMed Central

1977-01-01

Cationic local anesthetics have been reported to influence cellular responses to surface stimuli by interfering with the function of microtubules and microfilaments. Since unimpaired microtubule and microfilament functions are required by human polymorphonuclear leukocytes in order to respond normally to surface stimulation, we have studied effects of the local anesthetic, tetracaine on the function and morphology of these cells in vitro. Tetracaine (0.25--1.0 mM) significantly reduced extracellular release of the lysosomal enzymes, beta-glucuronidase and lysozyme from polymorphonuclear leukocytes exposed to serum-treated zymosan (a particulate stimulus), zymosan- treated serum (a soluble stimulus), and to the surface-active lectin, concanavalin A. Tetracaine also significantly reduced superoixde anion production (superoxide dismutase-inhibitable cytochrome c reduction) by these cells. Tetrancaine was not cytotoxic and its effects could be reversed completely by washing cells once with buffer. Electron microscope examination of tetracaine-treated cells revealed marked alterations of surface membranes. Microtubules and microfilaments appeared normal in "resting" polymorphonuclear leukocytes, but the increase in microtubules normally observed in stimulated cells was not seen after tetracaine treatment. These results suggest that tetracaine interferes with those interactions between immune reactants and the polymorphonuclear leukocyte cell surface which provoke exocytosis and increased oxidative metabolism. PMID:195003

Beta cells transfer vesicles containing insulin to phagocytes for presentation to T cells.

PubMed

Vomund, Anthony N; Zinselmeyer, Bernd H; Hughes, Jing; Calderon, Boris; Valderrama, Carolina; Ferris, Stephen T; Wan, Xiaoxiao; Kanekura, Kohsuke; Carrero, Javier A; Urano, Fumihiko; Unanue, Emil R

2015-10-06

Beta cells from nondiabetic mice transfer secretory vesicles to phagocytic cells. The passage was shown in culture studies where the transfer was probed with CD4 T cells reactive to insulin peptides. Two sets of vesicles were transferred, one containing insulin and another containing catabolites of insulin. The passage required live beta cells in a close cell contact interaction with the phagocytes. It was increased by high glucose concentration and required mobilization of intracellular Ca2+. Live images of beta cell-phagocyte interactions documented the intimacy of the membrane contact and the passage of the granules. The passage was found in beta cells isolated from islets of young nonobese diabetic (NOD) mice and nondiabetic mice as well as from nondiabetic humans. Ultrastructural analysis showed intraislet phagocytes containing vesicles having the distinct morphology of dense-core granules. These findings document a process whereby the contents of secretory granules become available to the immune system.

Osteocalcin protects pancreatic beta cell function and survival under high glucose conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kover, Karen, E-mail: kkover@cmh.edu; University of Missouri-Kansas City School of Medicine, Kansas City, MO 64108; Yan, Yun

Diabetes is characterized by progressive beta cell dysfunction and loss due in part to oxidative stress that occurs from gluco/lipotoxicity. Treatments that directly protect beta cell function and survival in the diabetic milieu are of particular interest. A growing body of evidence suggests that osteocalcin, an abundant non-collagenous protein of bone, supports beta cell function and proliferation. Based on previous gene expression data by microarray, we hypothesized that osteocalcin protects beta cells from glucose-induced oxidative stress. To test our hypothesis we cultured isolated rat islets and INS-1E cells in the presence of normal, high, or high glucose ± osteocalcin for up tomore » 72 h. Oxidative stress and viability/mitochondrial function were measured by H{sub 2}O{sub 2} assay and Alamar Blue assay, respectively. Caspase 3/7 activity was also measured as a marker of apoptosis. A functional test, glucose stimulated insulin release, was conducted and expression of genes/protein was measured by qRT-PCR/western blot/ELISA. Osteocalcin treatment significantly reduced high glucose-induced H{sub 2}O{sub 2} levels while maintaining viability/mitochondrial function. Osteocalcin also significantly improved glucose stimulated insulin secretion and insulin content in rat islets after 48 h of high glucose exposure compared to untreated islets. As expected sustained high glucose down-regulated gene/protein expression of INS1 and BCL2 while increasing TXNIP expression. Interestingly, osteocalcin treatment reversed the effects of high glucose on gene/protein expression. We conclude that osteocalcin can protect beta cells from the negative effects of glucose-induced oxidative stress, in part, by reducing TXNIP expression, thereby preserving beta cell function and survival. - Highlights: • Osteocalcin reduces glucose-induced oxidative stress in beta cells. • Osteocalcin preserves beta cell function and survival under stress conditions. • Osteocalcin reduces glucose-induced TXNIP expression in beta cells.« less

Large Extremity Peripheral Nerve Repair

DTIC Science & Technology

2014-10-01

has also been shown to produce human-beta-3-defensin. These antimicrobial peptides are implicated in the resistance of epithelial surfaces to...gonadotrophin receptors that regulate prostaglandin production and activity. Epithelial cells manufacture multiple vasoactive peptides , growth factors...200734 P-RCT (n Z 102) PT burns Processed Amnion vs topical antimicrobials . Significantly less dressing changes with amnion. Time to healing, length

Activation of Wnt signaling pathway by human papillomavirus E6 and E7 oncogenes in HPV16-positive oropharyngeal squamous carcinoma cells.

PubMed

Rampias, Theodore; Boutati, Eleni; Pectasides, Eirini; Sasaki, Clarence; Kountourakis, Panteleimon; Weinberger, Paul; Psyrri, Amanda

2010-03-01

We sought to determine the role of human papillomavirus (HPV) E6 and E7 oncogenes in nuclear beta-catenin accumulation, a hallmark of activated canonical Wnt signaling pathway. We used HPV16-positive oropharyngeal cancer cell lines 147T and 090, HPV-negative cell line 040T, and cervical cell lines SiHa (bearing integrated HPV16) and HeLa (bearing integrated HPV18) to measure the cytoplasmic and nuclear beta-catenin levels and the beta-catenin/Tcf transcriptional activity before and after E6/E7 gene silencing. Repression of HPV E6 and E7 genes induced a substantial reduction in nuclear beta-catenin levels. Luciferase assay showed that transcriptional activation of Tcf promoter by beta-catenin was lower after silencing. The protein levels of beta-catenin are tightly regulated by the ubiquitin/proteasome system. We therefore performed expression analysis of regulators of beta-catenin degradation and nuclear transport and showed that seven in absentia homologue (Siah-1) mRNA and protein levels were substantially upregulated after E6/E7 repression. Siah-1 protein promotes the degradation of beta-catenin through the ubiquitin/proteasome system. To determine whether Siah-1 is important for the proteasomal degradation of beta-catenin in HPV16-positive oropharyngeal cancer cells, we introduced a Siah-1 expression vector into 147T and 090 cells and found substantial reduction of endogenous beta-catenin in these cells. Thus, E6 and E7 are involved in beta-catenin nuclear accumulation and activation of Wnt signaling in HPV-induced cancers. In addition, we show the significance of the endogenous Siah-1-dependent ubiquitin/proteasome pathway for beta-catenin degradation and its regulation by E6/E7 viral oncoproteins in HPV16-positive oropharyngeal cancer cells.

Pleiotrophin regulates lung epithelial cell proliferation and differentiation during fetal lung development via beta-catenin and Dlk1.

PubMed

Weng, Tingting; Gao, Li; Bhaskaran, Manoj; Guo, Yujie; Gou, Deming; Narayanaperumal, Jeyaparthasarathy; Chintagari, Narendranath Reddy; Zhang, Kexiong; Liu, Lin

2009-10-09

The role of pleiotrophin in fetal lung development was investigated. We found that pleiotrophin and its receptor, protein-tyrosine phosphatase receptor beta/zeta, were highly expressed in mesenchymal and epithelial cells of the fetal lungs, respectively. Using isolated fetal alveolar epithelial type II cells, we demonstrated that pleiotrophin promoted fetal type II cell proliferation and arrested type II cell trans-differentiation into alveolar epithelial type I cells. Pleiotrophin also increased wound healing of injured type II cell monolayer. Knockdown of pleiotrophin influenced lung branching morphogenesis in a fetal lung organ culture model. Pleiotrophin increased the tyrosine phosphorylation of beta-catenin, promoted beta-catenin translocation into the nucleus, and activated T cell factor/lymphoid enhancer factor transcription factors. Dlk1, a membrane ligand that initiates the Notch signaling pathway, was identified as a downstream target of the pleiotrophin/beta-catenin pathway by endogenous dlk1 expression, promoter assay, and chromatin immunoprecipitation. These results provide evidence that pleiotrophin regulates fetal type II cell proliferation and differentiation via integration of multiple signaling pathways including pleiotrophin, beta-catenin, and Notch pathways.

Release of IL-1beta via IL-1beta-converting enzyme in a skin dendritic cell line exposed to 2,4-dinitrofluorobenzene.

PubMed

Matos, Teresa J; Jaleco, Sara P; Gonçalo, Margarida; Duarte, Carlos B; Lopes, M Celeste

2005-08-14

We used a mouse fetal skin dendritic cell line (FSDC) to study the effect of the strong allergen 2,4-dinitrofluorobenzene (DNFB) on interleukin (IL)-1beta release and IL-1beta receptor immunoreactivity. Stimulation with DNFB (30 minutes) increased IL-1 release without changing the mRNA levels of the protein. Furthermore, DNFB increased transiently the interleukin-1beta-converting enzyme (ICE) activity, as measured with its fluorogenic substrate Z-Tyr-Val-Ala-Asp-AFC. The ICE inhibitor Z-YVAD-FMK prevented the release of IL-1beta evoked by DNFB. Incubation of the cells with DNFB (30 minutes) strongly increased IL-1beta receptor immunoreactivity. The rapid effect of DNFB on the release of mature IL-1beta, without inducing an increase of IL-1beta mRNA in FSDC, suggests a posttranslational modification of pro-IL-1beta by ICE activity.

The insulin and islet amyloid polypeptide genes contain similar cell-specific promoter elements that bind identical beta-cell nuclear complexes.

PubMed Central

German, M S; Moss, L G; Wang, J; Rutter, W J

1992-01-01

The pancreatic beta cell makes several unique gene products, including insulin, islet amyloid polypeptide (IAPP), and beta-cell-specific glucokinase (beta GK). The functions of isolated portions of the insulin, IAPP, and beta GK promoters were studied by using transient expression and DNA binding assays. A short portion (-247 to -197 bp) of the rat insulin I gene, the FF minienhancer, contains three interacting transcriptional regulatory elements. The FF minienhancer binds at least two nuclear complexes with limited tissue distribution. Sequences similar to that of the FF minienhancer are present in the 5' flanking DNA of the human IAPP and rat beta GK genes and also the rat insulin II and mouse insulin I and II genes. Similar minienhancer constructs from the insulin and IAPP genes function as cell-specific transcriptional regulatory elements and compete for binding of the same nuclear factors, while the beta GK construct competes for protein binding but functions poorly as a minienhancer. These observations suggest that the patterns of expression of the beta-cell-specific genes result in part from sharing the same transcriptional regulators. Images PMID:1549125

Proteolytic processing of endogenous and recombinant beta 4 integrin subunit

PubMed Central

1992-01-01

The alpha 6 beta 4 integrin is a receptor involved in the interaction of epithelial cells with basement membranes. This integrin is unique among the known integrins in that its beta 4 subunit has a large cytoplasmic domain. The function of this cytoplasmic domain is not known. In this paper we show that the beta 4 subunit undergoes proteolytic processing in cultured cells and provide evidence that this also happens in tissues. Immunoprecipitation experiments indicated that the cytoplasmic domain of beta 4 is susceptible to a calcium-dependent protease present in cellular extracts. In vitro assays with purified calpain showed that this enzyme can cleave beta 4 at two distinct sites in the cytoplasmic domain, generating truncated molecules of 165 and 130 kD. Immunoblotting experiments performed on cultured epithelial cells using an antibody to a peptide modeled after the COOH-terminus of the beta 4 subunit showed 70-kD fragments and several fragments of molecular masses between 185 and 115 kD. Similar fragments were detected in CHO cells transfected with the full-length beta 4 cDNA, but not in control transfected cells or in cells transfected with a mutant cDNA lacking the epitope of the cytoplasmic peptide antibody. The sizes of the fragments indicated that both the intracellular and extracellular domains of beta 4 are proteolytically processed. To examine the processing of the beta 4 subunit in epithelial tissues in vivo, human skin frozen sections were stained with antibodies to the ectodomain or the cytoplasmic domain of beta 4. The distinct staining patterns obtained with the two types of antibodies provided evidence that beta 4 is proteolytically processed in vivo in skin. Analogous experiments performed on sections of the cornea suggested that beta 4 is not proteolytically processed at a detectable level in this tissue. Thus, cleavage of the beta 4 subunit occurs in a tissue-specific fashion. These results suggest a potential mechanism of modulating the activities of the alpha 6 beta 4 integrin. PMID:1500432

Modulation of cardiac myocyte phenotype in vitro by the composition and orientation of the extracellular matrix.

PubMed

Simpson, D G; Terracio, L; Terracio, M; Price, R L; Turner, D C; Borg, T K

1994-10-01

Cellular phenotype is the result of a dynamic interaction between a cell's intrinsic genetic program and the morphogenetic signals that serve to modulate the extent to which that program is expressed. In the present study we have examined how morphogenetic information might be stored in the extracellular matrix (ECM) and communicated to the neonatal heart cell (NHC) by the cardiac alpha 1 beta 1 integrin molecule. A thin film of type I collagen (T1C) was prepared with a defined orientation. This was achieved by applying T1C to the peripheral edge of a 100 mm culture dish. The T1C was then drawn across the surface of the dish in a continuous stroke with a sterile cell scraper and allowed to polymerize. When NHCs were cultured on this substrate, they spread, as a population, along a common axis in parallel with the gel lattice and expressed an in vivo-like phenotype. Individual NHCs displayed an elongated, rod-like shape and disclosed parallel arrays of myofibrils. These phenotypic characteristics were maintained for at least 4 weeks in primary culture. The evolution of this tissue-like organizational pattern was dependent upon specific interactions between the NHCs and the collagen-based matrix that were mediated by the cardiac alpha 1 beta 1 integrin complex. This conclusion was supported by a variety of experimental results. Altering the tertiary structure of the matrix or blocking the extracellular domains of either the cardiac alpha 1 or beta 1 integrin chain inhibited the expression of the tissue-like pattern of organization. Neither cell-to-cell contact or contractile function were necessary to induce the formation of the rod-like cell shape. However, beating activity was necessary for the assembly of a well-differentiated myofibrillar apparatus. These data suggest that the cardiac alpha 1 beta 1 integrin complex serves to detect and transduce phenotypic information stored within the tertiary structure of the surrounding matrix.

Programmed disorders of beta-cell development and function as one cause for type 2 diabetes? The GK rat paradigm.

PubMed

Portha, Bernard

2005-01-01

Now that the reduction in beta-mass has been clearly established in humans with type 2 diabetes mellitus (T2DM) 1-4, the debate focuses on the possible mechanisms responsible for decreased beta-cell number and impaired beta-cell function and their multifactorial etiology. Appropriate inbred rodent models are essential tools for identification of genes and environmental factors that increase the risk of abnormal beta-cell function and of T2DM. The information available in the Goto-Kakizaki (GK) rat, one of the best characterized animal models of spontaneous T2DM, are reviewed in such a perspective. We propose that the defective beta-cell mass and function in the GK model reflect the complex interactions of three pathogenic players: (1) several independent loci containing genes causing impaired insulin secretion; (2) gestational metabolic impairment inducing a programming of endocrine pancreas (decreased beta-cell neogenesis) which is transmitted to the next generation; and (3) secondary (acquired) loss of beta-cell differentiation due to chronic exposure to hyperglycemia (glucotoxicity). An important message is that the 'heritable' determinants of T2DM are not simply dependant on genetic factors, but probably involve transgenerational epigenetic responses. Copyright (c) 2005 John Wiley & Sons, Ltd.

Thiazolidinedione, a peroxisome proliferator-activated receptor-gamma ligand, modulates the E-cadherin/beta-catenin system in a human pancreatic cancer cell line, BxPC-3.

PubMed

Ohta, Tetsuo; Elnemr, Ayman; Yamamoto, Miyuki; Ninomiya, Itasu; Fushida, Sachio; Nishimura, Gen-Ichi; Fujimura, Takashi; Kitagawa, Hirohisa; Kayahara, Masato; Shimizu, Koichi; Yi, Shuangqin; Miwa, Koichi

2002-07-01

Activation of peroxisome proliferator-activated receptor (PPAR)-gamma induces terminal differentiation and growth inhibition associated with G1 cell cycle arrest in some cancer cells. The multifunctional molecule beta-catenin performs important roles in intercellular adhesion and signal transduction. However, no report has focused on actions of PPAR-gamma in regulating the E-cadherin/beta-catenin system. We examined whether thiazolidinedione (TZD), a potent PPAR-gamma ligand, could modulate the E-cadherin/beta-catenin system in a human pancreatic cancer cell line, BxPC-3, that has been found to express PPAR-gamma. According to Western blotting, TZD markedly increased differentiation markers including E-cadherin and carcinoembryonic antigen, while beta-catenin did not change significantly. In untreated cells, fluorescence immunostaining demonstrated beta-catenin predominantly in the cytoplasm and/or nucleus; in TZD-treated cells, beta-catenin localization had dramatically shifted to the plasma membrane, in association with increased E-cadherin at this site. Thus, a PPAR-gamma ligand appears to participate not only in induction of differentiation in pancreatic cancer cells, but also in the regulation of the E-cadherin/beta-catenin system. Such ligands may prove clinically useful as cytostatic anticancer agents.

Competition between Ski and CREB-binding protein for binding to Smad proteins in transforming growth factor-beta signaling.

PubMed

Chen, Weijun; Lam, Suvana S; Srinath, Hema; Schiffer, Celia A; Royer, William E; Lin, Kai

2007-04-13

The family of Smad proteins mediates transforming growth factor-beta (TGF-beta) signaling in cell growth and differentiation. Smads repress or activate TGF-beta signaling by interacting with corepressors (e.g. Ski) or coactivators (e.g. CREB-binding protein (CBP)), respectively. Specifically, Ski has been shown to interfere with the interaction between Smad3 and CBP. However, it is unclear whether Ski competes with CBP for binding to Smads and whether they can interact with Smad3 at the same binding surface on Smad3. We investigated the interactions among purified constructs of Smad, Ski, and CBP in vitro by size-exclusion chromatography, isothermal titration calorimetry, and mutational studies. Here, we show that Ski-(16-192) interacted directly with a homotrimer of receptor-regulated Smad protein (R-Smad), e.g. Smad2 or Smad3, to form a hexamer; Ski-(16-192) interacted with an R-Smad.Smad4 heterotrimer to form a pentamer. CBP-(1941-1992) was also found to interact directly with an R-Smad homotrimer to form a hexamer and with an R-Smad.Smad4 heterotrimer to form a pentamer. Moreover, these domains of Ski and CBP competed with each other for binding to Smad3. Our mutational studies revealed that domains of Ski and CBP interacted with Smad3 at a portion of the binding surface of the Smad anchor for receptor activation. Our results suggest that Ski negatively regulates TGF-beta signaling by replacing CBP in R-Smad complexes. Our working model suggests that Smad protein activity is delicately balanced by Ski and CBP in the TGF-beta pathway.

Preadipocyte 11beta-hydroxysteroid dehydrogenase type 1 is a keto-reductase and contributes to diet-induced visceral obesity in vivo.

PubMed

De Sousa Peixoto, R A; Turban, S; Battle, J H; Chapman, K E; Seckl, J R; Morton, N M

2008-04-01

Glucocorticoid excess promotes visceral obesity and cardiovascular disease. Similar features are found in the highly prevalent metabolic syndrome in the absence of high levels of systemic cortisol. Although elevated activity of the glucocorticoid-amplifying enzyme 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) within adipocytes might explain this paradox, the potential role of 11beta-HSD1 in preadipocytes is less clear; human omental adipose stromal vascular (ASV) cells exhibit 11beta-dehydrogenase activity (inactivation of glucocorticoids) probably due to the absence of cofactor provision by hexose-6-phosphate dehydrogenase. To clarify the depot-specific impact of 11beta-HSD1, we assessed whether preadipocytes in ASV from mesenteric (as a representative of visceral adipose tissue) and sc tissue displayed 11beta-HSD1 activity in mice. 11beta-HSD1 was highly expressed in freshly isolated ASV cells, predominantly in preadipocytes. 11beta-HSD1 mRNA and protein levels were comparable between ASV and adipocyte fractions in both depots. 11beta-HSD1 was an 11beta-reductase, thus reactivating glucocorticoids in ASV cells, consistent with hexose-6-phosphate dehydrogenase mRNA expression. Unexpectedly, glucocorticoid reactivation was higher in intact mesenteric ASV cells despite a lower expression of 11beta-HSD1 mRNA and protein (homogenate activity) levels than sc ASV cells. This suggests a novel depot-specific control over 11beta-HSD1 enzyme activity. In vivo, high-fat diet-induced obesity was accompanied by increased visceral fat preadipocyte differentiation in wild-type but not 11beta-HSD1(-/-) mice. The results suggest that 11beta-HSD1 reductase activity is augmented in mouse mesenteric preadipocytes where it promotes preadipocyte differentiation and contributes to visceral fat accumulation in obesity.

Mono-(2-ethylhexyl) phthalate (MEHP) regulates glucocorticoid metabolism through 11{beta}-hydroxysteroid dehydrogenase 2 in murine gonadotrope cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hong, Dun; Department of Orthopedics, Taizhou Hospital, Wenzhou Medical College, Lin Hai, ZJ 317000; Li, Xing-Wang

2009-11-13

Di-(2-ethylhexyl) phthalate (DEHP) and its metabolite mono-(2-ethylhexyl) phthalate (MEHP) have been classified as toxicants to the reproductive system at the testis level and DEHP may also impair reproductive axis function at the pituitary levels. However, MEHP is 10-fold more potent than DEHP in toxicity and little is known about the toxicological effect of MEHP on pituitary. In this study, we demonstrated that 11{beta}-hydroxysteroid dehydrogenase type 2 (11{beta}-HSD2), not 11{beta}-HSD1, is strongly expressed in murine gonadotrope L{beta}T2 cells. Interestingly, MEHP inhibited Hsd11b2 mRNA level and 11{beta}-HSD2 enzyme activity in L{beta}T2 cells at as low as 10{sup -7} M. Corticosterone (CORT) atmore » a concentration of 10{sup -6} M significantly inhibited L{beta}T2 cell proliferation after 2-day culture, and 10{sup -6} M RU486, an antagonist of glucocorticoid receptor (GR), reversed this inhibition. However, in the presence of 10{sup -5} or 10{sup -4} M MEHP, the minimal concentration of CORT to inhibit the proliferation of L{beta}T2 cells was lowered to 10{sup -7} M, and 10{sup -6} M RU486 was not able to completely reverse the CORT effect. In conclusion, along with the regulation of GR, 11{beta}-HSD2 may have a key role in glucocorticoid metabolism in L{beta}T2 cells. MEHP may participate in the glucocorticoid metabolism in L{beta}T2 cells through inhibition of 11{beta}-HSD2 enzyme activity. Such perturbation may be of pathological significance as MEHP may interfere with the reproductive system at pituitary level through regulation of glucocorticoid metabolism, especially in neonates with higher risk of phthalates exposure.« less

The Golgi localization of phosphatidylinositol transfer protein beta requires the protein kinase C-dependent phosphorylation of serine 262 and is essential for maintaining plasma membrane sphingomyelin levels.

PubMed

van Tiel, Claudia M; Westerman, Jan; Paasman, Marten A; Hoebens, Martha M; Wirtz, Karel W A; Snoek, Gerry T

2002-06-21

Recombinant mouse phosphatidylinositol transfer protein (PI-TP)beta is a substrate for protein kinase C (PKC)-dependent phosphorylation in vitro. Based on site-directed mutagenesis and two-dimensional tryptic peptide mapping, Ser(262) was identified as the major site of phosphorylation and Ser(165) as a minor phosphorylation site. The phospholipid transfer activities of wild-type PI-TP beta and PI-TP beta(S262A) were identical, whereas PI-TP beta(S165A) was completely inactive. PKC-dependent phosphorylation of Ser(262) also had no effect on the transfer activity of PI-TP beta. To investigate the role of Ser(262) in the functioning of PI-TP beta, wtPI-TP beta and PI-TP beta(S262A) were overexpressed in NIH3T3 fibroblast cells. Two-dimensional PAGE analysis of cell lysates was used to separate PI-TP beta from its phosphorylated form. After Western blotting, wtPI-TP beta was found to be 85% phosphorylated, whereas PI-TP beta(S262A) was not phosphorylated. In the presence of the PKC inhibitor GF 109203X, the phosphorylated form of wtPI-TP beta was strongly reduced. Immunolocalization showed that wtPI-TP beta was predominantly associated with the Golgi membranes. In the presence of the PKC inhibitor, wtPI-TP beta was distributed throughout the cell similar to what was observed for PI-TP beta(S262A). In contrast to wtPI-TP beta overexpressors, cells overexpressing PI-TP beta(S262A) were unable to rapidly replenish sphingomyelin in the plasma membrane upon degradation by sphingomyelinase. This implies that PKC-dependent association with the Golgi complex is a prerequisite for PI-TP beta to express its effect on sphingomyelin metabolism.

Functional Hydrogel Materials Inspired by Amyloid

NASA Astrophysics Data System (ADS)

Schneider, Joel

2012-02-01

Protein assembly resulting in the formation of amyloid fibrils, assemblies rich in cross beta-sheet structure, is normally thought of as a deleterious event associated with disease. However, amyloid formation is also involved in a diverse array of normal biological functions such as cell adhesion, melanin synthesis, insect defense mechanism and modulation of water surface tension by fungi and bacteria. These findings indicate that Nature has evolved to take advantage of large, proteinaceous fibrillar assemblies to elicit function. We are designing functional materials, namely hydrogels, from peptides that self-assembled into fibrillar networks, rich in cross beta-sheet structure. These gels can be used for the direct encapsulation and delivery of small molecule-, protein- and cell-based therapeutics. Loaded gels exhibit shear-thinning/self-healing mechanical properties enabling their delivery via syringe. In addition to their use for delivery, we have found that some of these gels display antibacterial activity. Although cytocompatible towards mammalian cells, the hydrogels can kill a broad spectrum of bacteria on contact.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu Jiawei; Division of Molecular Medicine, Harbor-UCLA Medical Center, David Geffen School of Medicine, University of California Los Angeles, Torrance, CA 90502; Lu Zhenyu

The corneal endothelial cells form a boundary layer between anterior chamber and cornea. This single cell layer is important to maintain cornea transparency by eliciting net fluid transport into the anterior chamber. Injuries of the corneal endothelial layer in humans lead to corneal swelling and translucence. This hindrance is thought to be due to limited proliferative capacity of the endothelial layer. Fibroblast growth factor 2 (FGF-2) and transforming growth factor-beta 2 (TGF-{beta}2) are both found in aqueous humor, and these two cytokines promote and inhibit cell growth, respectively. The intracellular signaling mechanisms by which TGF-{beta}2 suppresses the mitogenic response tomore » FGF-2, however, remain unclear. We have addressed this question by investigating potential crosstalk between FGF-2-induced and TGF-{beta}2-regulated intracellular signaling events in cultured bovine corneal endothelial (BCE) cells. We found that TGF-{beta}2 and FGF-2 oppositely affect BCE cell proliferation and TGF-{beta}2 can override the stimulating effects of FGF-2 by increasing COX-2 expression in these cells. Consistent with these findings, overexpression of COX-2 significantly reduced FGF-2-induced cell proliferation whereas a COX-2 specific inhibitor NS398 reversed the effect of TGF-{beta}2 on FGF-2-induced cell proliferation. The COX-2 product prostaglandin E2 (PGE-2) blocks FGF-2-induced cell proliferation. Whereas FGF-2 stimulates cell proliferation by activating the AKT pathway, TGF-{beta}2 and PGE-2 both inhibit this pathway. In accordance with the effect of PGE-2, cAMP also inhibits FGF-2-induced AKT activation. These findings suggest that the mitogenic response to FGF-2 in vivo in the corneal endothelial layer may be inhibited by TGF-{beta}2-induced suppression of the PI3-kinase/AKT signaling pathway.« less

[Effect of Yiguan Decoction on differentiation of bone marrow mesenchymal stem cells into hepatocyte-like cells: an experimental research].

PubMed

Ping, Jian; Chen, Hong-Yun; Yang, Zhou; Yang, Cheng; Xu, Lie-Ming

2014-03-01

To observe the effect of Yiguan Decoction (YGD) on differentiation of bone marrow mesenchymal stem cells (BMSCs) into hepatocyte-like cells in vitro. Rat BMSCs were isolated using whole bone marrow adherent method. The properties of BMSCs were identified by analyzing the expression of surface cytokines by flow cytometry. The third passage cells were differentiated into fat cells to identify their features. BMSCs were incubated with hepatocyte growth factor (HGF) plus fibroblast growth factor 4 (FGF4) or YGD containing serum YGD for 21 days. The mRNA expression of alpha-fetoprotein (alphaAFP), albumin (Alb), and hepatocyte nuclear factor 4alpha (HNF4alpha) were detected by real time PCR. Expression of AFP and cytokeratin 18 (CK18) protein was detected by cell immunofluorescence. Glycogen synthesis was observed using periodic acid-Schiff stain (PAS). CK18, Wnt 3alpha, and alphacatenin protein expressions were detected by Western blot. High expression of CD90, CD29, and CD44, and low expression of CD34 and CD11b were observed in BMSCs isolated by whole bone mar- row adherent method, and numerous lipid droplets were observed in BMSCs using oil red O staining. Both YGD containing serum and growth factor stimulated the expression levels of Alb, AFP, HNF4alpha mRNA and CK18 protein. The down-regulated expression of Wnt 3alpha and beta-catenin could be detected at 21 days after induction. The synthesized glycogen granule could be seen. Down-regulated Wnt 3alpha and beta-catenin expression could also be observed. YGD could induce the differentiation of rat BMSCs into hepatocyte-like cells, which was related to down-regulating Wnt/beta-catenin signal pathway.

Involvement of DNA polymerase beta in repairing oxidative damages induced by antitumor drug adriamycin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu Shukun; Wu Mei; Zhang Zunzhen, E-mail: zhangzunzhen@163.co

2010-08-01

Adriamycin (ADM) is a widely used antineoplastic drug. However, the increasing cellular resistance has become a serious limitation to ADM clinical application. The most important mechanism related to ADM-induced cell death is oxidative DNA damage mediated by reactive oxygen species (ROS). Base excision repair (BER) is a major pathway in the repair of DNA single strand break (SSB) and oxidized base. In this study, we firstly applied the murine embryo fibroblasts wild-type (pol {beta} +/+) and homozygous pol {beta} null cell (pol {beta} -/-) as a model to investigate ADM DNA-damaging effects and the molecular basis underlying these effects. Here,more » cellular sensitivity to ADM was examined using colorimetric assay and colony forming assay. ADM-induced cellular ROS level and the alteration of superoxide dismutase (SOD) activity were measured by commercial kits. Further, DNA strand break, chromosomal damage and gene mutation were assessed by comet assay, micronucleus test and hprt gene mutation assay, respectively. The results showed that pol {beta} -/- cells were more sensitive to ADM compared with pol {beta} +/+ cells and more severe SSB and chromosomal damage as well as higher hprt gene mutation frequency were observed in pol {beta} -/- cells. ROS level in pol {beta} -/- cells increased along with decreased activity of SOD. These results demonstrated that pol {beta} deficiency could enable ROS accumulation with SOD activity decrease, further elevate oxidative DNA damage, and subsequently result in SSB, chromosome cleavage as well as gene mutation, which may be partly responsible for the cytotoxicity of ADM and the hypersensitivity of pol {beta} -/- cells to ADM. These findings suggested that pol {beta} is vital for repairing oxidative damage induced by ADM.« less

The effect of smoking cessation pharmacotherapies on pancreatic beta cell function

DOE Office of Scientific and Technical Information (OSTI.GOV)

Woynillowicz, Amanda K.; Raha, Sandeep; Nicholson, Catherine J.

The goal of our study was to evaluate whether drugs currently used for smoking cessation (i.e., nicotine replacement therapy, varenicline [a partial agonist at nicotinic acetylcholine receptors (nAChR)] and bupropion [which acts in part as a nAChR antagonist]) can affect beta cell function and determine the mechanism(s) of this effect. INS-1E cells, a rat beta cell line, were treated with nicotine, varenicline and bupropion to determine their effects on beta cell function, mitochondrial electron transport chain enzyme activity and cellular/oxidative stress. Treatment of INS-1E cells with equimolar concentrations (1 μM) of three test compounds resulted in an ablation of normalmore » glucose-stimulated insulin secretion by the cells. This disruption of normal beta cell function was associated with mitochondrial dysfunction since all three compounds tested significantly decreased the activity of mitochondrial electron transport chain enzyme activity. These results raise the possibility that the currently available smoking cessation pharmacotherapies may also have adverse effects on beta cell function and thus glycemic control in vivo. Therefore whether or not the use of nicotine replacement therapy, varenicline and bupropion can cause endocrine changes which are consistent with impaired pancreatic function warrants further investigation. -- Highlights: ► Smoking cessation drugs have the potential to disrupt beta cell function in vitro. ► The effects of nicotine, varenicline and bupropion are similar. ► The impaired beta cell function is mediated by mitochondrial dysfunction. ► If similar effects are seen in vivo, these drugs may increase the risk of diabetes.« less

Regulation of CD93 cell surface expression by protein kinase C isoenzymes.

PubMed

Ikewaki, Nobunao; Kulski, Jerzy K; Inoko, Hidetoshi

2006-01-01

Human CD93, also known as complement protein 1, q subcomponent, receptor (C1qRp), is selectively expressed by cells with a myeloid lineage, endothelial cells, platelets, and microglia and was originally reported to be involved in the complement protein 1, q subcomponent (C1q)-mediated enhancement of phagocytosis. The intracellular molecular events responsible for the regulation of its expression on the cell surface, however, have not been determined. In this study, the effect of protein kinases in the regulation of CD93 expression on the cell surface of a human monocyte-like cell line (U937), a human NK-like cell line (KHYG-1), and a human umbilical vein endothelial cell line (HUV-EC-C) was investigated using four types of protein kinase inhibitors, the classical protein kinase C (cPKC) inhibitor Go6976, the novel PKC (nPKC) inhibitor Rottlerin, the protein kinase A (PKA) inhibitor H-89 and the protein tyrosine kinase (PTK) inhibitor herbimycin A at their optimum concentrations for 24 hr. CD93 expression was analyzed using flow cytometry and glutaraldehyde-fixed cellular enzyme-linked immunoassay (EIA) techniques utilizing a CD93 monoclonal antibody (mAb), mNI-11, that was originally established in our laboratory as a CD93 detection probe. The nPKC inhibitor Rottlerin strongly down-regulated CD93 expression on the U937 cells in a dose-dependent manner, whereas the other inhibitors had little or no effect. CD93 expression was down-regulated by Go6976, but not by Rottlerin, in the KHYG-1 cells and by both Rottlerin and Go6976 in the HUV-EC-C cells. The PKC stimulator, phorbol myristate acetate (PMA), strongly up-regulated CD93 expression on the cell surface of all three cell-lines and induced interleukin-8 (IL-8) production by the U937 cells and interferon-gamma (IFN-gamma) production by the KHYG-1 cells. In addition, both Go6976 and Rottlerin inhibited the up-regulation of CD93 expression induced by PMA and IL-8 or IFN-gamma production in the respective cell-lines. Whereas recombinant tumor necrosis factor-alpha (rTNF-alpha) slightly up-regulated CD93 expression on the U937 cells, recombinant interleukin-1beta (rIL-1beta), recombinant interleukin-2 (rIL-2), recombinant interferon-gamma (rIFN-gamma) and lipopolysaccharide (LPS) had no effect. Taken together, these findings indicate that the regulation of CD93 expression on these cells involves the PKC isoenzymes.

Transforming growth factor beta induced FoxP3+ regulatory T cells suppress Th1 mediated experimental colitis.

PubMed

Fantini, M C; Becker, C; Tubbe, I; Nikolaev, A; Lehr, H A; Galle, P; Neurath, M F

2006-05-01

The imbalance between effector and regulatory T cells plays a central role in the pathogenesis of inflammatory bowel diseases. In addition to the thymus, CD4+CD25+ regulatory T cells can be induced in the periphery from a population of CD25- T cells by treatment with transforming growth factor beta (TGF-beta). Here, we analysed the in vivo function of TGF-beta induced regulatory T (Ti-Treg) cells in experimental colitis. Ti-Treg cells were generated in cell culture in the presence or absence of TGF-beta and tested for their regulatory potential in experimental colitis using the CD4+CD62L+ T cell transfer model. Ti-Treg cells significantly suppressed Th1 mediated colitis on CD4+CD62L+ T cell transfer in vivo, as shown by high resolution endoscopy, histology, immunohistochemistry, and cytokine analysis. Further analysis of in vivo and in vitro expanded Ti-Treg cells showed that exogenous interleukin 2 (IL-2) was crucial for survival and expansion of these cells. Our data suggest that regulatory Ti-Treg cells expand by TGF-beta and exogenous IL-2 derived from effector T cells at the site of inflammation. In addition to Tr1 and thymic CD4+CD25+ T cells, peripheral Ti-Treg cells emerge as a class of regulatory T cells with therapeutic potential in T cell mediated chronic intestinal inflammation.

Selective destruction of mouse islet beta cells by human T lymphocytes in a newly-established humanized type 1 diabetic model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Yong, E-mail: yongzhao@uic.edu; Guo, Chengshan; Hwang, David

2010-09-03

Research highlights: {yields} Establish a human immune-mediated type 1 diabetic model in NOD-scid IL2r{gamma}{sup null} mice. {yields} Using the irradiated diabetic NOD mouse spleen mononuclear cells as trigger. {yields} The islet {beta} cells were selectively destroyed by infiltrated human T cells. {yields} The model can facilitate translational research to find a cure for type 1 diabetes. -- Abstract: Type 1 diabetes (T1D) is caused by a T cell-mediated autoimmune response that leads to the loss of insulin-producing {beta} cells. The optimal preclinical testing of promising therapies would be aided by a humanized immune-mediated T1D model. We develop this model inmore » NOD-scid IL2r{gamma}{sup null} mice. The selective destruction of pancreatic islet {beta} cells was mediated by human T lymphocytes after an initial trigger was supplied by the injection of irradiated spleen mononuclear cells (SMC) from diabetic nonobese diabetic (NOD) mice. This resulted in severe insulitis, a marked loss of total {beta}-cell mass, and other related phenotypes of T1D. The migration of human T cells to pancreatic islets was controlled by the {beta} cell-produced highly conserved chemokine stromal cell-derived factor 1 (SDF-1) and its receptor C-X-C chemokine receptor (CXCR) 4, as demonstrated by in vivo blocking experiments using antibody to CXCR4. The specificity of humanized T cell-mediated immune responses against islet {beta} cells was generated by the local inflammatory microenvironment in pancreatic islets including human CD4{sup +} T cell infiltration and clonal expansion, and the mouse islet {beta}-cell-derived CD1d-mediated human iNKT activation. The selective destruction of mouse islet {beta} cells by a human T cell-mediated immune response in this humanized T1D model can mimic those observed in T1D patients. This model can provide a valuable tool for translational research into T1D.« less

Requirement for Pdx1 in specification of latent endocrine progenitors in zebrafish

PubMed Central

2011-01-01

Background Insulin-producing beta cells emerge during pancreas development in two sequential waves. Recently described later-forming beta cells in zebrafish show high similarity to second wave mammalian beta cells in developmental capacity. Loss-of-function studies in mouse and zebrafish demonstrated that the homeobox transcription factors Pdx1 and Hb9 are both critical for pancreas and beta cell development and discrete stage-specific requirements for these genes have been uncovered. Previously, exocrine and endocrine cell recovery was shown to follow loss of pdx1 in zebrafish, but the progenitor cells and molecular mechanisms responsible have not been clearly defined. In addition, interactions of pdx1 and hb9 in beta cell formation have not been addressed. Results To learn more about endocrine progenitor specification, we examined beta cell formation following morpholino-mediated depletion of pdx1 and hb9. We find that after early beta cell reduction, recovery occurs following loss of either pdx1 or hb9 function. Unexpectedly, simultaneous knockdown of both hb9 and pdx1 leads to virtually complete and persistent beta cell deficiency. We used a NeuroD:EGFP transgenic line to examine endocrine cell behavior in vivo and developed a novel live-imaging technique to document emergence and migration of late-forming endocrine precursors in real time. Our data show that Notch-responsive progenitors for late-arising endocrine cells are predominantly post mitotic and depend on pdx1. By contrast, early-arising endocrine cells are specified and differentiate independent of pdx1. Conclusions The nearly complete beta cell deficiency after combined loss of hb9 and pdx1 suggests functional cooperation, which we clarify as distinct roles in early and late endocrine cell formation. A novel imaging approach permitted visualization of the emergence of late endocrine cells within developing embryos for the first time. We demonstrate a pdx1-dependent progenitor population essential for the formation of duct-associated, second wave endocrine cells. We further reveal an unexpectedly low mitotic activity in these progenitor cells, indicating that they are set aside early in development. PMID:22034951

Characterization of the synthesis and expression of the GTA-kinase from transformed and normal rodent cells.

PubMed

Kerr, M; Fischer, J E; Purushotham, K R; Gao, D; Nakagawa, Y; Maeda, N; Ghanta, V; Hiramoto, R; Chegini, N; Humphreys-Beher, M G

1994-08-02

The murine transformed cell line YC-8 and beta-adrenergic receptor agonist (isoproternol) treated rat and mouse parotid gland acinar cells ectopically express cell surface beta 1-4 galactosyltransferase during active proliferation. This activity is dependent upon the expression of the GTA-kinase (p58) in these cells. Using total RNA, cDNA clones for the protein coding region of the kinase were isolated by reverse transcriptase-PCR cloning. DNA sequence analysis failed to show sequence differences with the normal homolog from mouse cells although Southern blot analysis of YC-8, and a second cell line KI81, indicated changes in the restriction enzyme digestion profile relative to murine cell lines which do not express cell surface galactosyltransferase. The rat cDNA clone from isoproterenol-treated salivary glands showed a high degree of protein and nucleic acid sequence homology to the GTA-kinase from both murine and human sources. Northern blot analysis of YC-8 and a control cell line LSTRA revealed the synthesis of a major 3.0 kb mRNA from both cell lines plus the unique expression of a 4.5 kb mRNA in the YC-8 cells. Reverse transcriptase-PCR of LSTRA and YC-8 confirmed the increased steady state levels of the GTA-kinase mRNA in YC-8. In the mouse, induction of cell proliferation by isoproterenol resulted in a 50-fold increase in steady state mRNA levels for the kinase over the low level of expression in quiescent cells. Expression of the rat 3' untranslated region in rat parotid cells in vitro led to an increased rate of DNA synthesis, cell number an ectopic expression of cell surface galactosyltransferase in the sense orientation. Antisense expression or vector alone did not alter growth characteristics of acinar cells. A polyclonal antibody monospecific to a murine amino terminal peptide sequence revealed a uniform distribution of GTA-kinase over the cytoplasm of acinar and duct cells of control mouse parotid glands. However, upon growth stimulation, kinase was detected primarily in a perinuclear and nuclear immunostaining pattern. Western blot analysis confirmed a translocation from a cytoplasmic localization in both LSTRA and quiescent salivary cells to a membrane-associated localization in YC-8 and proliferating salivary cells.

Functionally graded scaffolds for the engineering of interface tissues using hybrid twin screw extrusion/electrospinning technology

NASA Astrophysics Data System (ADS)

Erisken, Cevat

Tissue engineering is the application of the principles of engineering and life sciences for the development of biological alternatives for improvement or regeneration of native tissues. Native tissues are complex structures with functions and properties changing spatially and temporally, and engineering of such structures requires functionally graded scaffolds with composition and properties changing systematically along various directions. Utilization of a new hybrid technology integrating the controlled feeding, compounding, dispersion, deaeration, and pressurization capabilities of extrusion process with electrospinning allows incorporation of liquids and solid particles/nanoparticles into polymeric fibers/nanofibers for fabrication of functionally graded non-woven meshes to be used as scaffolds in engineering of tissues. The capabilities of the hybrid technology were demonstrated with a series of scaffold fabrication and cell culturing studies along with characterization of biomechanical properties. In the first study, the hybrid technology was employed to generate concentration gradations of beta-tricalcium phosphate (beta-TCP) nanoparticles in a polycaprolactone (PCL) binder, between two surfaces of nanofibrous scaffolds. These scaffolds were seeded with pre-osteoblastic cell line (MC3T3-E1) to attempt to engineer cartilage-bone interface, and after four weeks, the tissue constructs revealed formation of continuous gradations in extracellular matrix akin to cartilage-bone interface in terms of distributions of mineral concentrations and biomechanical properties. In a second demonstration of the hybrid technology, graded differentiation of stem cells was attempted by using insulin, a known stimulator of chondrogenic differentiation, and beta-glycerol phosphate (beta-GP), for mineralization. Concentrations of insulin and beta-GP in PCL were controlled to monotonically increase and decrease, respectively, along the length of scaffolds, which were then seeded with adipose derived stromal cells (h-ADSCs). Analysis of resulting tissue constructs revealed chondrocytic differentiation of h-ADSCs, with both the chondrocytic cell concentration and mineralization varying as a function of distributions of concentrations of insulin and beta-GP, respectively. The investigation also covered characterization of biomechanical properties of native bovine osteochondral tissue samples, which were then compared with biomechanical properties of tissue constructs at different stages of development. The hybrid technology developed in this thesis should provide another enabling platform for the fabrication of functionally graded scaffolds that aim to mimic the elegant gradations found in myriad native tissues.

Human beta-cell precursors mature into functional insulin-producing cells in an immunoisolation device: implications for diabetes cell therapies.

PubMed

Lee, Seung-Hee; Hao, Ergeng; Savinov, Alexei Y; Geron, Ifat; Strongin, Alex Y; Itkin-Ansari, Pamela

2009-04-15

Islet transplantation is limited by the need for chronic immunosuppression and the paucity of donor tissue. As new sources of human beta-cells are developed (e.g., stem cell-derived tissue), transplanting them in a durable device could obviate the need for immunosuppression, while also protecting the patient from any risk of tumorigenicity. Here, we studied (1) the survival and function of encapsulated human beta-cells and their progenitors and (2) the engraftment of encapsulated murine beta-cells in allo- and autoimmune settings. Human islets and human fetal pancreatic islet-like cell clusters were encapsulated in polytetrafluorethylene devices (TheraCyte) and transplanted into immunodeficient mice. Graft survival and function was measured by immunohistochemistry, circulating human C-peptide levels, and blood glucose levels. Bioluminescent imaging was used to monitor encapsulated neonatal murine islets. Encapsulated human islet-like cell clusters survived, replicated, and acquired a level of glucose responsive insulin secretion sufficient to ameliorate hyperglycemia in diabetic mice. Bioluminescent imaging of encapsulated murine neonatal islets revealed a dynamic process of cell death followed by regrowth, resulting in robust long-term allograft survival. Further, in the non-obese diabetic (NOD) mouse model of type I diabetes, encapsulated primary beta-cells ameliorated diabetes without stimulating a detectable T-cell response. We demonstrate for the first time that human beta-cells function is compatible with encapsulation in a durable, immunoprotective device. Moreover, our study suggests that encapsulation of beta-cells before terminal differentiation will be a successful approach for new cell-based therapies for diabetes, such as those derived from stem cells.

Chemical and physical effects on the adhesion, maturation, and survival of monocytes, macrophages, and foreign body giant cells

NASA Astrophysics Data System (ADS)

Collier, Terry Odell, III

Injury caused by biomedical device implantation initiates inflammatory and wound healing responses. Cells migrate to the site of injury to degrade bacteria and toxins, create new vasculature, and form new and repair injured tissue. Blood-proteins rapidly adsorb onto the implanted material surface and express adhesive ligands which mediate cell adhesion on the material surface. Monocyte-derived macrophages and multi-nucleated foreign body giant cells adhere to the surface and degrade the surface of the material. Due to the role of macrophage and foreign body giant cell on material biocompatibility and biostability, the effects of surface chemistry, surface topography and specific proteins on the maturation and survival of monocytes, macrophages and foreign body giant cells has been investigated. Novel molecularly designed materials were used to elucidate the dynamic interactions which occur between inflammatory cells, proteins and surfaces. The effect of protein and protein adhesion was investigated using adhesive protein depleted serum conditions on RGD-modified and silane modified surfaces. The effects of surface chemistry were investigated using temperature responsive surfaces of poly (N-isopropylacrylamide) and micropatterned surfaces of N-(2 aminoethyl)-3-aminopropyltrimethoxysilane regions on an interpenetrating polymer network of polyacrylamide and poly(ethylene glycol). The physical effects were investigated using polyimide scaffold materials and polyurethane materials with surface modifying end groups. The depletion of immunoglobulin G caused decreased levels of macrophage adhesion, foreign body giant cell formation and increased levels of apoptosis. The temporal nature of macrophage adhesion was observed with changing effectiveness of adherent cell detachment with time, which correlated to increased expression of beta1 integrin receptors on detached macrophages with time. The limited ability of the micropatterned surface, polyimide scaffold and surface modified polyurethane materials to control macrophage adhesion indicates the complexity of macrophage adhesion and protein adsorption onto a surface. These studies have indicated components and adhesive mechanisms which can be utilized to create materials with enhanced resistance to macrophage adhesion and/or degradative abilities.

C/EBPβ Promotes STAT3 Expression and Affects Cell Apoptosis and Proliferation in Porcine Ovarian Granulosa Cells.

PubMed

Yuan, Xiaolong; Zhou, Xiaofeng; He, Yingting; Zhong, Yuyi; Zhang, Ailing; Zhang, Zhe; Zhang, Hao; Li, Jiaqi

2018-06-13

Previous studies suggest that signal transducer and activator of transcription 3 (STAT3) and CCAAT/enhancer binding protein beta (C/EBPβ) play an essential role in ovarian granulosa cells (GCs) for mammalian follicular development. Several C/EBPβ putative binding sites were previously predicted on the STAT3 promoter in mammals. However, the molecular regulation of C/EBPβ on STAT3 and their effects on cell proliferation and apoptosis remain virtually unexplored in GCs. Using porcine GCs as a model, the 5′-deletion, luciferase report assay, mutation, chromatin immunoprecipitation, Annexin-V/PI staining and EdU assays were applied to investigate the molecular mechanism for C/EBPβ regulating the expression of STAT3 and their effects on the cell proliferation and apoptosis ability. We found that over and interfering with the expression of C/EBPβ significantly increased and decreased the messenger RNA (mRNA) and protein levels of STAT3 , respectively. The dual luciferase reporter assay showed that C/EBPβ directly bound at −1397/−1387 of STAT3 to positively regulate the mRNA and protein expressions of STAT3 . Both C/EBPβ and STAT3 were observed to inhibit cell apoptosis and promote cell proliferation. Furthermore, C/EBPβ might enhance the antiapoptotic and pro-proliferative effects of STAT3 . These results would be of great insight in further exploring the molecular mechanism of C/EBPβ and STAT3 on the function of GCs and the development of ovarian follicles in mammals.

Origin of higher affinity to RNA of the N-terminal RNA-binding domain than that of the C-terminal one of a mouse neural protein, musashi1, as revealed by comparison of their structures, modes of interaction, surface electrostatic potentials, and backbone dynamics.

PubMed

Miyanoiri, Youhei; Kobayashi, Hisanori; Imai, Takao; Watanabe, Michinao; Nagata, Takashi; Uesugi, Seiichi; Okano, Hideyuki; Katahira, Masato

2003-10-17

Musashi1 is an RNA-binding protein abundantly expressed in the developing mouse central nervous system. Its restricted expression in neural precursor cells suggests that it is involved in maintenance of the character of progenitor cells. Musashi1 contains two ribonucleoprotein-type RNA-binding domains (RBDs), RBD1 and RBD2, the affinity to RNA of RBD1 being much higher than that of RBD2. We previously reported the structure and mode of interaction with RNA of RBD2. Here, we have determined the structure and mode of interaction with RNA of RBD1. We have also analyzed the surface electrostatic potential and backbone dynamics of both RBDs. The two RBDs exhibit the same ribo-nucleoprotein-type fold and commonly make contact with RNA on the beta-sheet side. On the other hand, there is a remarkable difference in surface electrostatic potential, the beta-sheet of RBD1 being positively charged, which is favorable for binding negatively charged RNA, but that of RBD2 being almost neutral. There is also a difference in backbone dynamics, the central portion of the beta-sheet of RBD1 being flexible, but that of RBD2 not being flexible. The flexibility of RBD1 may be utilized in the recognition process to facilitate an induced fit. Thus, comparative studies have revealed the origin of the higher affinity of RBD1 than that of RBD2 and indicated that the affinity of an RBD to RNA is not governed by its fold alone but is also determined by its surface electrostatic potential and/or backbone dynamics. The biological role of RBD2 with lower affinity is also discussed.

Neurturin-deficient mice develop dry eye and keratoconjunctivitis sicca.

PubMed

Song, Xiu Jun; Li, De-Quan; Farley, William; Luo, Li Hui; Heuckeroth, Robert O; Milbrandt, Jeffrey; Pflugfelder, Stephen C

2003-10-01

Neurturin has been identified as a neurotrophic factor for parasympathetic neurons. Neurturin-deficient (NRTN(-/-)) mice have defective parasympathetic innervation of their lacrimal glands. This study was conducted to evaluate tear function and ocular surface phenotype in NRTN(-/-) mice. Determined by tail genomic DNA PCR, 25 NRTN(-/-) mice and 17 neurturin-normal (NRTN(+/+)) mice aged 6 weeks to 4 months were evaluated. Aqueous tear production, tear fluorescein clearance and corneal sensation were serially measured. Corneal permeability to AlexaFluor dextran (AFD; Molecular Probes, Eugene, OR) was measured by a fluorometric assay at 485 nm excitation and 530 nm emission. Histology was evaluated in PAS-stained sections. Mucin and HLA class II (IA) antigen were assessed by immunofluorescent staining. Tear IL-1beta was measured by ELISA, and tear matrix metalloproteinase (MMP)-9 by zymography. Gene expression in the corneal epithelia was analyzed by semiquantitative RT-PCR. In comparison to that in age-matched NRTN(+/+) mice, aqueous tear production, tear fluorescein clearance, and corneal sensation were significantly reduced in NRTN(-/-) mice, whereas corneal permeability to AFD was significantly increased. Immunoreactive MUC-4 and -5AC mucin and goblet cell density (P < 0.001) in the conjunctiva of NRTN(-/-) mice were lower than in NRTN(+/+) mice. The expression of MUC-1 and -4 mRNA by the corneal epithelium was reduced in NRTN(-/-) mice. There were a significantly greater number of IA antigen-positive conjunctival epithelial cells in NRTN(-/-) mice than NRTN(+/+) mice. Tear fluid IL-1beta and MMP-9 concentrations and the expression of IL-1beta, TNF-alpha, macrophage inflammatory protein (MIP)-2, cytokine-induced neutrophil chemoattractant (KC), and MMP-9 mRNA by the corneal epithelia were significantly increased in NRTN(-/-) mice, compared with NRTN(+/+) mice. Neurturin-deficient mice show phenotypic changes and ocular surface inflammation that mimic human keratoconjunctivitis sicca. This model supports the importance of a functional ocular surface-central nervous system-lacrimal gland sensory-autonomic neural network in maintaining ocular surface health and homeostasis.

Cleaning efficacy of hydroxypropyl-beta-cyclodextrin for biofouling reduction on reverse osmosis membranes.

PubMed

Alayande, Abayomi Babatunde; Kim, Lan Hee; Kim, In S

2016-01-01

In this study, an environmentally friendly compound, hydroxypropyl-beta-cyclodextrin (HP-β-CD) was applied to clean reverse osmosis (RO) membranes fouled by microorganisms. The cleaning with HP-β-CD removed the biofilm and resulted in a flux recovery ratio (FRR) of 102%. As cleaning efficiency is sometimes difficult to determine using flux recovery data alone, attached bacterial cells and extracellular polymeric substances (EPS) were quantified after cleaning the biofouled membrane with HP-β-CD. Membrane surface characterization using scanning electron microscopy (SEM), attenuated total reflectance Fourier transform infrared (ATR-FTIR) and atomic force microscopy (AFM) confirmed the effectiveness of HP-β-CD in removal of biofilm from the RO membrane surface. Finally, a comparative study was performed to investigate the competitiveness of HP-β-CD with other known cleaning agents such as sodium dodecyl sulfate (SDS), ethylenediaminetetraacetic acid (EDTA), Tween 20, rhamnolipid, nisin, and surfactin. In all cases, HP-β-CD was superior.

Barrier role of actin filaments in regulated mucin secretion from airway goblet cells.

PubMed

Ehre, Camille; Rossi, Andrea H; Abdullah, Lubna H; De Pestel, Kathleen; Hill, Sandra; Olsen, John C; Davis, C William

2005-01-01

Airway goblet cells secrete mucin onto mucosal surfaces under the regulation of an apical, phospholipase C/G(q)-coupled P2Y(2) receptor. We tested whether cortical actin filaments negatively regulate exocytosis in goblet cells by forming a barrier between secretory granules and plasma membrane docking sites as postulated for other secretory cells. Immunostaining of human lung tissues and SPOC1 cells (an epithelial, mucin-secreting cell line) revealed an apical distribution of beta- and gamma-actin in ciliated and goblet cells. In goblet cells, actin appeared as a prominent subplasmalemmal sheet lying between granules and the apical membrane, and it disappeared from SPOC1 cells activated by purinergic agonist. Disruption of actin filaments with latrunculin A stimulated SPOC1 cell mucin secretion under basal and agonist-activated conditions, whereas stabilization with jasplakinolide or overexpression of beta- or gamma-actin conjugated to yellow fluorescent protein (YFP) inhibited secretion. Myristoylated alanine-rich C kinase substrate, a PKC-activated actin-plasma membrane tethering protein, was phosphorylated after agonist stimulation, suggesting a translocation to the cytosol. Scinderin (or adseverin), a Ca(2+)-activated actin filament severing and capping protein was cloned from human airway and SPOC1 cells, and synthetic peptides corresponding to its actin-binding domains inhibited mucin secretion. We conclude that actin filaments negatively regulate mucin secretion basally in airway goblet cells and are dynamically remodeled in agonist-stimulated cells to promote exocytosis.

Transforming growth factor-beta in the chicken fundal layers: an immunohistochemical study.

PubMed

Mathis, Ute; Schaeffel, Frank

2010-06-01

In the chicken model of myopia, it has first been shown that imposing defocus to the retina results in active remodelling of the sclera which, in turn, results in axial length changes of the eye. Transforming growth factor-beta (TGF-beta) is one of the scleral growth modulators but its cellular localization in the fundal layers, colocalization and function are not well known. The aim of the current study was to investigate the cellular distribution of the three isoforms TGF-beta1, 2 and 3 by immunohistochemical labelling. Furthermore, the effects of visual experience that induces refractive errors on TGF-beta2 labelling were examined. Transversal cryostat sections of the fundal layers were analyzed by indirect immunofluorescent labelling and cell counts. Visual experience was changed by having the chicks wear either diffusers, or positive or negative lenses of 7D power in front of the right eyes for various periods of time. Left eyes served as uncovered controls. All TGF-beta isoforms were localized in both scleral layers. In choroid, diffuse labelling of all isoforms was found. In retina, TGF-beta1 and 3 were detected in bipolar, amacrine and ganglion cells and TGF-beta2 in amacrine and ganglion cells. To further characterize these cells, double-labelling with known amacrine and bipolar cell markers was performed (calbindin, cellular retinoic acid binding protein (CRABP), Islet1, Lim3 and protein kinase C (PKC)). TGF-beta1, 2 and 3 could be colocalized with calbindin and CRABP in single amacrine cells. TGF-beta1-positive bipolar cells were immunoreactive to Lim3. TGF-beta1 and 3 were never colocalized with PKC in bipolar cells. Also, colocalization with peptides known to be involved in myopia development in chicks, such as glucagon, or vasointestinal polypeptide and the key enzyme for dopamine synthesis, tyrosine hydroxylase, was not observed. Lenses or diffusers, worn by the chicks for various periods of time, had no effect on TGF-beta2 immunoreactivity in choroid or sclera, or on the number of TGF-beta2 (active and latent form) expressing amacrine cells. This result did not change when the two identified populations of TGF-beta2 expressing amacrine cells (one calbindin-positive and the other CRABP-positive) were separately considered. Also no modulation was seen in choroid, although an earlier study had found changes in TGF-beta2 mRNA after lens treatment. The lack of any visually-induced changes in retina or choroid suggests that TGF-beta may not represent a key molecule in the retino-choroidal signalling cascade although it has previously been shown to have a primary role in scleral remodelling. Copyright 2010 Elsevier Ltd. All rights reserved.

Functional characterization of the beta-adrenergic receptor subtypes expressed by CA1 pyramidal cells in the rat hippocampus.

PubMed

Hillman, Kristin L; Doze, Van A; Porter, James E

2005-08-01

Recent studies have demonstrated that activation of the beta-adrenergic receptor (AR) using the selective beta-AR agonist isoproterenol (ISO) facilitates pyramidal cell long-term potentiation in the cornu ammonis 1 (CA1) region of the rat hippocampus. We have previously analyzed beta-AR genomic expression patterns of 17 CA1 pyramidal cells using single cell reverse transcription-polymerase chain reaction, demonstrating that all samples expressed the beta2-AR transcript, with four of the 17 cells additionally expressing mRNA for the beta1-AR subtype. However, it has not been determined which beta-AR subtypes are functionally expressed in CA1 for these same pyramidal neurons. Using cell-attached recordings, we tested the ability of ISO to increase pyramidal cell action potential (AP) frequency in the presence of subtype-selective beta-AR antagonists. ICI-118,551 [(+/-)-1-[2,3-(dihydro-7-methyl-1H-inden-4-yl)oxy]-3-[(1-methylethyl)amino]-2-butanol] and butoxamine [alpha-[1-(t-butylamino)ethyl]-2,5-dimethoxybenzyl alcohol) hydrochloride], agents that selectively block the beta2-AR, produced significant parallel rightward shifts in the concentration-response curves for ISO. From these curves, apparent equilibrium dissociation constant (K(b)) values of 0.3 nM for ICI-118,551 and 355 nM for butoxamine were calculated using Schild regression analysis. Conversely, effective concentrations of the selective beta1-AR antagonists CGP 20712A [(+/-)-2-hydroxy-5-[2-([2-hydroxy-3-(4-[1-methyl-4-(trifluoromethyl)-1H-imidazol-2-yl]phenoxy)propyl]amino)ethoxy]-benzamide methanesulfonate] and atenolol [4-[2'-hydroxy-3'-(isopropyl-amino)propoxy]phenylacetamide] did not significantly affect the pyramidal cell response to ISO. However, at higher concentrations, atenolol significantly decreased the potency for ISO-mediated AP frequencies. From these curves, an apparent atenolol K(b) value of 3162 nM was calculated. This pharmacological profile for subtype-selective beta-AR antagonists indicates that beta2-AR activation is mediating the increased AP frequency. Knowledge of functional AR expression in CA1 pyramidal neurons will aid future long-term potentiation studies by allowing selective manipulation of specific beta-AR subtypes.

Functional Connectivity in Islets of Langerhans from Mouse Pancreas Tissue Slices

PubMed Central

Stožer, Andraž; Gosak, Marko; Dolenšek, Jurij; Perc, Matjaž; Marhl, Marko; Rupnik, Marjan Slak; Korošak, Dean

2013-01-01

We propose a network representation of electrically coupled beta cells in islets of Langerhans. Beta cells are functionally connected on the basis of correlations between calcium dynamics of individual cells, obtained by means of confocal laser-scanning calcium imaging in islets from acute mouse pancreas tissue slices. Obtained functional networks are analyzed in the light of known structural and physiological properties of islets. Focusing on the temporal evolution of the network under stimulation with glucose, we show that the dynamics are more correlated under stimulation than under non-stimulated conditions and that the highest overall correlation, largely independent of Euclidean distances between cells, is observed in the activation and deactivation phases when cells are driven by the external stimulus. Moreover, we find that the range of interactions in networks during activity shows a clear dependence on the Euclidean distance, lending support to previous observations that beta cells are synchronized via calcium waves spreading throughout islets. Most interestingly, the functional connectivity patterns between beta cells exhibit small-world properties, suggesting that beta cells do not form a homogeneous geometric network but are connected in a functionally more efficient way. Presented results provide support for the existing knowledge of beta cell physiology from a network perspective and shed important new light on the functional organization of beta cell syncitia whose structural topology is probably not as trivial as believed so far. PMID:23468610

GLP-1 mediates antiapoptotic effect by phosphorylating Bad through a beta-arrestin 1-mediated ERK1/2 activation in pancreatic beta-cells.

PubMed

Quoyer, Julie; Longuet, Christine; Broca, Christophe; Linck, Nathalie; Costes, Safia; Varin, Elodie; Bockaert, Joël; Bertrand, Gyslaine; Dalle, Stéphane

2010-01-15

Strategies based on activating GLP-1 receptor (GLP-1R) are intensively developed for the treatment of type 2 diabetes. The exhaustive knowledge of the signaling pathways linked to activated GLP-1R within the beta-cells is of major importance. In beta-cells, GLP-1 activates the ERK1/2 cascade by diverse pathways dependent on either Galpha(s)/cAMP/cAMP-dependent protein kinase (PKA) or beta-arrestin 1, a scaffold protein. Using pharmacological inhibitors, beta-arrestin 1 small interfering RNA, and islets isolated from beta-arrestin 1 knock-out mice, we demonstrate that GLP-1 stimulates ERK1/2 by two temporally distinct pathways. The PKA-dependent pathway mediates rapid and transient ERK1/2 phosphorylation that leads to nuclear translocation of the activated kinases. In contrast, the beta-arrestin 1-dependent pathway produces a late ERK1/2 activity that is restricted to the beta-cell cytoplasm. We further observe that GLP-1 phosphorylates the cytoplasmic proapoptotic protein Bad at Ser-112 but not at Ser-155. We find that the beta-arrestin 1-dependent ERK1/2 activation engaged by GLP-1 mediates the Ser-112 phosphorylation of Bad, through p90RSK activation, allowing the association of Bad with the scaffold protein 14-3-3, leading to its inactivation. beta-Arrestin 1 is further found to mediate the antiapoptotic effect of GLP-1 in beta-cells through the ERK1/2-p90RSK-phosphorylation of Bad. This new regulatory mechanism engaged by activated GLP-1R involving a beta-arrestin 1-dependent spatiotemporal regulation of the ERK1/2-p90RSK activity is now suspected to participate in the protection of beta-cells against apoptosis. Such signaling mechanism may serve as a prototype to generate new therapeutic GLP-1R ligands.

Biotin uptake by mouse and human pancreatic beta cells/islets: a regulated, lipopolysaccharide-sensitive carrier-mediated process

PubMed Central

Ghosal, Abhisek; Sekar, Thillai V.

2014-01-01

Biotin is essential for the normal function of pancreatic beta cells. These cells obtain biotin from their surroundings via transport across their cell membrane. Little is known about the uptake mechanism involved, how it is regulated, and how it is affected by internal and external factors. We addressed these issues using the mouse-derived pancreatic beta-TC-6 cells and freshly isolated mouse and human primary pancreatic beta cells as models. The results showed biotin uptake by pancreatic beta-TC-6 cells occurs via a Na+-dependent, carrier-mediated process, that is sensitive to desthiobiotin, as well as to pantothenic acid and lipoate; the process is also saturable as a function of concentration (apparent Km = 22.24 ± 5.5 μM). These cells express the sodium-dependent multivitamin transporter (SMVT), whose knockdown (with doxycycline-inducible shRNA) led to a sever inhibition in biotin uptake. Similarly, uptake of biotin by mouse and human primary pancreatic islets is Na+-dependent and carrier-mediated, and both cell types express SMVT. Biotin uptake by pancreatic beta-TC-6 cells is also adaptively regulated (via transcriptional mechanism) by extracellular substrate level. Chronic treatment of pancreatic beta-TC-6 cells with bacterial lipopolysaccharides (LPS) leads to inhibition in biotin uptake. This inhibition is mediated via a Toll-Like receptor 4-mediated process and involves a decrease in membrane expression of SMVT. These findings show, for the first time, that pancreatic beta cells/islets take up biotin via a specific and regulated carrier-mediated process, and that the process is sensitive to the effect of LPS. PMID:24904078

Effects of alpha/beta-androstenediol immune regulating hormones on bone remodeling and apoptosis in osteoblasts.

PubMed

Urban, Nicole H; Chamberlin, Brett; Ramage, Samuel; Roberts, Zachary; Loria, Roger M; Beckman, Matthew J

2008-06-01

A large body of evidence suggests that the immune system directly impacts bone physiology. We tested whether immune regulating hormones (IRH), 17beta-androstenediol (beta-AED), 7beta,17beta-androstenetriol (beta-AET) or the 17alpha-androstenediol (alpha-AED), and 7alpha,17beta-androstenetriol (alpha-AET) metabolites could directly influence bone remodeling in vitro using human fetal osteoblasts (FOB-9). The impact on bone remodeling was examined by comparing the ratio of RANKL/OPG gene expression in response to AED and AET compounds. The alpha-AED was found to significantly increase in the ratio of RANKL/OPG gene expression and altering the morphology of RANKL stained FOB-9 cells. Cell viability was assessed using a Live/Dead assay. Again alpha-AED was unique in its ability to reduce the proportion of viable cells, and to induce mild apoptosis of FOB-9 cells. Treatment of FOB-9 cells with WY14643, an activator of PPAR-alpha and -gamma, also significantly elevated the percentage of dead cells. This increase was abolished by co-treatment with GW9962, a specific inhibitor of PPAR-gamma. Analysis of PPAR-gamma mRNA by Quantitative RT-PCR and its activation by DNA binding demonstrated that alpha-AED increased PPAR-gamma activation by 19%, while beta-AED conferred a 37% decrease in PPAR-gamma activation. In conclusion, alpha-AED opposed beta-AED by elevating a bone resorption scenario in osteoblast cells. The increase in RANKL/OPG is modulated by an activation of PPAR-gamma that in turn caused mild apoptosis of FOB-9 cells.

Parasitic heat loss reduction in AMTEC cells by heat shield optimization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borkowski, C.A.; Svedberg, R.C.; Hendricks, T.J.

1997-12-31

Alkali metal thermal to electric conversion (AMTEC) cell performance can be increased by the proper design of thermal radiative shielding internal to the AMTEC cell. These heat shields essentially lower the radiative heat transfer between the heat input zone of the cell and the heat rejection zone of the cell. In addition to lowering the radiative heat transfer between the heat input and heat rejection surfaces of the cell, the shields raise the AMTEC cell performance by increasing the temperature of the beta alumina solid electrolyte (BASE). This increase in temperature of the BASE tube allows the evaporator temperature tomore » be increased without sodium condensing within the BASE tubes. Experimental testing and theoretical analysis have been performed to compare the relative merits of two candidate heat shield packages: (1) chevron, and (2) cylindrical heat shields. These two heat shield packages were compared to each other and a baseline cell which had no heat shields installed. For the two heat shield packages, the reduction in total heat transfer is between 17--27% for the heat input surface temperature varying from 700 C, 750 C, and 800 C with the heat rejection surface temperature kept at 300 C.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liang, Wenqing, E-mail: liangwenqing_1234@126.com; Yang, Chengwei; Qian, Yu

Highlights: Black-Right-Pointing-Pointer {beta}-Catenin expression were markedly down-regulated by CTNNB1 shRNA. Black-Right-Pointing-Pointer CTNNB1 shRNA could inhibit the proliferation of RPMI8226 cells. Black-Right-Pointing-Pointer Significantly profound apoptotic cell death in CTNNB1 shRNA cells. Black-Right-Pointing-Pointer In vivo, CTNNB1 silence led to a growth inhibition of myeloma growth. Black-Right-Pointing-Pointer c-myc and {beta}-catenin in the expression cells of cleaved caspase-3 were increased. -- Abstract: Multiple myeloma (MM) is thrombogenic as a consequence of multiple hemostatic effects. Overexpression of {beta}-catenin has been observed in several types of malignant tumors, including MM. However, the relationship between {beta}-catenin expression and MM remains unclear. In the present study, RNA interferencemore » was used to inhibit {beta}-catenin expression in RPMI8226 cells. RT-PCR and Western blotting analyses showed that {beta}-catenin mRNA and protein expression were markedly down-regulated by CTNNB1 shRNA. Western blotting showed that the protein levels of cyclin D1 and glutamine synthetase were downregulated and supported the transcriptional regulatory function of {beta}-catenin. The MTT assay showed that CTNNB1 shRNA could have significant inhibitory effects on the proliferation of RPMI8226 cells. The TOPflash reporter assay demonstrated significant downregulation after CTNNB1 shRNA transfection in RPMI8226 cells. Flow cytometric analyses also showed significantly profound apoptosis in CTNNB1 shRNA cells. We found CTNNB1 silence led to growth inhibition of MM growth in vivo. Immunohistochemical analyses showed that c-myc and {beta}-catenin were reduced in CTNNB1 shRNA tumor tissues, but that expression of cleaved caspase-3 was increased. These results show that {beta}-catenin could be a new therapeutic agent that targets the biology of MM cells.« less

Overexpression of {alpha}-catenin increases osteoblastic differentiation in mouse mesenchymal C3H10T1/2 cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Dohee; Yang, Jae-Yeon; Shin, Chan Soo, E-mail: csshin@snu.ac.kr

2009-05-15

{alpha}- and {beta}-Catenin link cadherins to the actin-based cytoskeleton at adherens junctions and regulate cell-cell adhesion. Although roles of cadherins and canonical Wnt-/{beta}-catenin-signaling in osteoblastic differentiation have been extensively studied, the role of {alpha}-catenin is not known. Murine embryonic mesenchymal stem cells, C3H10T1/2 cells, were transduced with retrovirus encoding {alpha}-catenin (MSCV-{alpha}-catenin-HA-GFP). In the presence of Wnt-3A conditioned medium or osteogenic medium ({beta}-glycerol phosphate and ascorbic acid), cells overexpressing {alpha}-catenin showed enhanced osteoblastic differentiation as measured by alkaline phosphatase (ALP) staining and ALP activity assay compared to cells transduced with empty virus (MSCV-GFP). In addition, mRNA expression of osteocalcin and Runx2more » was significantly increased compared to control. Cell aggregation assay revealed that {alpha}-catenin overexpression has significantly increased cell-cell aggregation. However, cellular {beta}-catenin levels (total, cytoplasmic-nuclear ratio) and {beta}-catenin-TCF/LEF transcriptional activity did not change by overexpression of {alpha}-catenin. Knock-down of {alpha}-catenin using siRNA decreased osteoblastic differentiation as measured by ALP assay. These results suggest that {alpha}-catenin overexpression increases osteoblastic differentiation by increasing cell-cell adhesion rather than Wnt-/{beta}-catenin-signaling.« less

N-terminal tyrosine phosphorylation of caveolin-2 negates anti-proliferative effect of transforming growth factor beta in endothelial cells

PubMed Central

Abel, Britain; Willoughby, Cara; Jang, Sungchan; Cooper, Laura; Xie, Leike; Vo-Ransdell, Chi; Sowa, Grzegorz

2012-01-01

Here we show that tyrosine phosphorylation of caveolin-2 (Cav-2) negatively regulates the anti-proliferative function of transforming growth factor beta (TGF-beta) in endothelial cells. In contrast to wild-type-Cav-2, retroviral re-expression of Y19/27F-Cav-2 in Cav-2 knockout endothelial cells did not affect anti-proliferative effect of TGF-beta compared to empty vector. Conversely, although less effective than wild-type, re-expression of S23/36A-Cav-2 reduced the effect of TGF-beta compared to empty vector. This differential effect of tyrosine and serine phosphorylation mutants of Cav-2 correlated with TGF-beta-induced Smad3 phosphorylation and transcriptional activation of plasminogen activator inhibitor-1. Thus tyrosine-phosphorylated Cav-2 counteracts anti-proliferative effect of TGF-beta in endothelial cells. PMID:22819829

Adenomatous polyposis coli protein (APC)-independent regulation of beta-catenin/Tcf-4 mediated transcription in intestinal cells.

PubMed Central

Baulida, J; Batlle, E; García De Herreros, A

1999-01-01

Alterations in the transcriptional activity of the beta-catenin-Tcf complex have been associated with the earlier stages of colonic transformation. We show here that the activation of protein kinase C by the phorbol ester PMA in several intestinal cell lines increases the levels of beta-catenin detected in the nucleus and augments the transcriptional activity mediated by beta-catenin. The response to PMA was not related to modifications in the cytosolic levels of beta-catenin and was observed not only in cells with wild-type adenomatous polyposis coli protein (APC) but also in APC-deficient cells. Binding assays in vitro revealed that PMA facilitates the interaction of the beta-catenin with the nuclear structure. Our results therefore show that beta-catenin-mediated transcription can be regulated independently of the presence of APC. PMID:10567241

Clostridium perfringens enterotoxin is a superantigen reactive with human T cell receptors V beta 6.9 and V beta 22

PubMed Central

1992-01-01

Candidate superantigens were screened for their ability to induce lysis of human histocompatibility leukocyte antigen class II-positive targets by human CD8+ influenza-specific cytotoxic T cell (CTL) lines. Clostridium perfringens enterotoxin (CPET) induced major histocompatibility complex unrestricted killing by some but not all CTL lines. Using "anchored" polymerase chain reactions, CPET was shown to selectively stimulate peripheral blood lymphocytes bearing T cell receptor V beta 6.9 and V beta 22 in five healthy donors. V beta 24, V beta 21, V beta 18, V beta 5, and V beta 6.1-5 appeared to be weakly stimulated. Antigen processing was not required for CPET to induce proliferation. Like the staphylococcal enterotoxins, CPET is a major cause of food poisoning. These data suggest that superantigenic and enterotoxigenic properties may be closely linked. PMID:1512551

Digestion of Yeasts and Beta-1,3-Glucanases in Mosquito Larvae: Physiological and Biochemical Considerations.

PubMed

Souza, Raquel Santos; Diaz-Albiter, Hector Manuel; Dillon, Vivian Maureen; Dillon, Rod J; Genta, Fernando Ariel

2016-01-01

Aedes aegypti larvae ingest several kinds of microorganisms. In spite of studies regarding mosquito digestion, little is known about the nutritional utilization of ingested cells by larvae. We investigated the effects of using yeasts as the sole nutrient source for A. aegypti larvae. We also assessed the role of beta-1,3-glucanases in digestion of live yeast cells. Beta-1,3-glucanases are enzymes which hydrolyze the cell wall beta-1,3-glucan polyssacharide. Larvae were fed with cat food (controls), live or autoclaved Saccharomyces cerevisiae cells and larval weight, time for pupation and adult emergence, larval and pupal mortality were measured. The presence of S. cerevisiae cells inside the larval gut was demonstrated by light microscopy. Beta-1,3-glucanase was measured in dissected larval samples. Viability assays were performed with live yeast cells and larval gut homogenates, with or without addition of competing beta-1,3-glucan. A. aegypti larvae fed with yeast cells were heavier at the 4th instar and showed complete development with normal mortality rates. Yeast cells were efficiently ingested by larvae and quickly killed (10% death in 2 h, 100% in 48 h). Larvae showed beta-1,3-glucanase in head, gut and rest of body. Gut beta-1,3-glucanase was not derived from ingested yeast cells. Gut and rest of body activity was not affected by the yeast diet, but head homogenates showed a lower activity in animals fed with autoclaved S. cerevisiae cells. The enzymatic lysis of live S. cerevisiae cells was demonstrated using gut homogenates, and this activity was abolished when excess beta-1,3-glucan was added to assays. These results show that live yeast cells are efficiently ingested and hydrolyzed by A. aegypti larvae, which are able to fully-develop on a diet based exclusively on these organisms. Beta-1,3-glucanase seems to be essential for yeast lytic activity of A. aegypti larvae, which possess significant amounts of these enzyme in all parts investigated.

A critical role for beta cell M3 muscarinic acetylcholine receptors in regulating insulin release and blood glucose homeostasis in vivo.

PubMed

Gautam, Dinesh; Han, Sung-Jun; Hamdan, Fadi F; Jeon, Jongrye; Li, Bo; Li, Jian Hua; Cui, Yinghong; Mears, David; Lu, Huiyan; Deng, Chuxia; Heard, Thomas; Wess, Jürgen

2006-06-01

One of the hallmarks of type 2 diabetes is that pancreatic beta cells fail to release sufficient amounts of insulin in the presence of elevated blood glucose levels. Insulin secretion is modulated by many hormones and neurotransmitters including acetylcholine, the major neurotransmitter of the peripheral parasympathetic nervous system. The physiological role of muscarinic acetylcholine receptors expressed by pancreatic beta cells remains unclear at present. Here, we demonstrate that mutant mice selectively lacking the M3 muscarinic acetylcholine receptor subtype in pancreatic beta cells display impaired glucose tolerance and greatly reduced insulin release. In contrast, transgenic mice selectively overexpressing M3 receptors in pancreatic beta cells show a profound increase in glucose tolerance and insulin release. Moreover, these mutant mice are resistant to diet-induced glucose intolerance and hyperglycemia. These findings indicate that beta cell M3 muscarinic receptors play a key role in maintaining proper insulin release and glucose homeostasis.

Expression and function of glycogen synthase kinase-3 in human hair follicles.

PubMed

Yamauchi, Koichi; Kurosaka, Akira

2010-05-01

Beta-catenin is involved in the hair follicle morphogenesis and stem cell differentiation, and inhibition of glycogen synthase kinase-3 (GSK-3) increases beta-catenin concentration in the cytoplasm. To examine the effects of GSK-3 inhibition on the hair follicle epithelium, we first examined the expression of GSK-3 in plucked human hair follicles by RT-PCR and found GSK-3 expression in hair follicles. Western blotting with a GSK-3beta-specific antibody, Y174, also demonstrated GSK-3beta expression in the follicles. Moreover, GSK-3beta immunostaining with Y174 showed that GSK-3beta colocalized with hair follicle bulge markers. Contrary to GSK-3beta, GSK-3 alpha was widely expressed throughout the follicles when immunostained with a specific antibody, EP793Y. We then investigated the influence of GSK-3 inhibition. A GSK-3 inhibitor, BIO, promoted the growth of human outer root sheath cells, which could be cultured for up to four passages. The BIO-treated cells exhibited smaller and more undifferentiated morphology than control cells. Moreover, in organ culture of plucked human hair, outer root sheath cells in the middle of a hair follicle proliferated when cultured with BIO. These results indicate that GSK-3beta is expressed in hair bulge stem cells and BIO promotes the growth of ORS cells, possibly by regulating the GSK-3 signaling pathway.

The selective solubilization of different murine splenocyte membrane fractions with lubrol WX and triton X-100 distinguishes two forms of Ia antigens. A cell surface (alpha, beta) and an intracellular (alpha, Ii, beta).

PubMed

Moosic, J P; Sung, E; Nilson, A; Jones, P P; McKean, D J

1982-08-25

The selective solubilization of different murine lymphocyte membrane compartments with several nonionic detergents was used to study the subcellular distribution of two distinct forms of lymphocyte cell recognition structures (Ia antigens). Ia antigens were isolated with a monoclonal anti-Ia immunoadsorbent from murine splenocytes that had been solubilized with four different nonionic detergents. Analyses of the immunoprecipitates indicated that Lubrol WX was selectively solubilizing a subpopulation of Ia consisting of mature highly glycosylated alpha and beta polypeptides which were not associated with Ii polypeptide. A second Ia subpopulation consisting of less glycosylated cytoplasmic precursor alpha and beta polypeptides associated with Ii polypeptide was immunoprecipitated from the Lubrol WX-insoluble material after solubilizing this material with Triton X-100. Comparable results were obtained when HLA-DR antigens were similarly isolated from cultured human lymphoblastoid cells. This selective solubilization phenomenon was not unique to Ia antigens. Only mature highly glycosylated H-2K molecules were immunoprecipitated from the Lubrol WX-soluble material while the less glycosylated precursor H-2K molecules were immunoprecipitated from the Triton X-100-solubilized Lubrol-insoluble material. These data directly demonstrate that the Ii polypeptide is exclusively associated with the intracellular Ia antigen cytoplasmic precursor molecules. These data also indicate that, under the conditions used in these experiments, Lubrol WX does not completely solubilize integral membrane proteins that have previously been shown to be associated with the rough endoplasmic reticulum.

Calcium Channels in Postnatal Development of Rat Pancreatic Beta Cells and Their Role in Insulin Secretion

PubMed Central

García-Delgado, Neivys; Velasco, Myrian; Sánchez-Soto, Carmen; Díaz-García, Carlos Manlio; Hiriart, Marcia

2018-01-01

Pancreatic beta cells during the first month of development acquire functional maturity, allowing them to respond to variations in extracellular glucose concentration by secreting insulin. Changes in ionic channel activity are important for this maturation. Within the voltage-gated calcium channels (VGCC), the most studied channels are high-voltage-activated (HVA), principally L-type; while low-voltage-activated (LVA) channels have been poorly studied in native beta cells. We analyzed the changes in the expression and activity of VGCC during the postnatal development in rat beta cells. We observed that the percentage of detection of T-type current increased with the stage of development. T-type calcium current density in adult cells was higher than in neonatal and P20 beta cells. Mean HVA current density also increased with age. Calcium current behavior in P20 beta cells was heterogeneous; almost half of the cells had HVA current densities higher than the adult cells, and this was independent of the presence of T-type current. We detected the presence of α1G, α1H, and α1I subunits of LVA channels at all ages. The Cav 3.1 subunit (α1G) was the most expressed. T-type channel blockers mibefradil and TTA-A2 significantly inhibited insulin secretion at 5.6 mM glucose, which suggests a physiological role for T-type channels at basal glucose conditions. Both, nifedipine and TTA-A2, drastically decreased the beta-cell subpopulation that secretes more insulin, in both basal and stimulating glucose conditions. We conclude that changes in expression and activity of VGCC during the development play an important role in physiological maturation of beta cells. PMID:29556214

Regulation of calcium-permeable TRPV2 channel by insulin in pancreatic beta-cells.

PubMed

Hisanaga, Etsuko; Nagasawa, Masahiro; Ueki, Kohjiro; Kulkarni, Rohit N; Mori, Masatomo; Kojima, Itaru

2009-01-01

Calcium-permeable cation channel TRPV2 is expressed in pancreatic beta-cells. We investigated regulation and function of TRPV2 in beta-cells. Translocation of TRPV2 was assessed in MIN6 cells and cultured mouse beta-cells by transfecting TRPV2 fused to green fluorescent protein or TRPV2 containing c-Myc tag in the extracellular domain. Calcium entry was assessed by monitoring fura-2 fluorescence. In MIN6 cells, TRPV2 was observed mainly in cytoplasm in an unstimulated condition. Addition of exogenous insulin induced translocation and insertion of TRPV2 to the plasma membrane. Consistent with these observations, insulin increased calcium entry, which was inhibited by tranilast, an inhibitor of TRPV2, or by knockdown of TRPV2 using shRNA. A high concentration of glucose also induced translocation of TRPV2, which was blocked by nefedipine, diazoxide, and somatostatin, agents blocking glucose-induced insulin secretion. Knockdown of the insulin receptor attenuated insulin-induced translocation of TRPV2. Similarly, the effect of insulin on TRPV2 translocation was not observed in a beta-cell line derived from islets obtained from a beta-cell-specific insulin receptor knockout mouse. Knockdown of TRPV2 or addition of tranilast significantly inhibited insulin secretion induced by a high concentration of glucose. Likewise, cell growth induced by serum and glucose was inhibited by tranilast or by knockdown of TRPV2. Finally, insulin-induced translocation of TRPV2 was observed in cultured mouse beta-cells, and knockdown of TRPV2 reduced insulin secretion induced by glucose. TRPV2 is regulated by insulin and is involved in the autocrine action of this hormone on beta-cells.

Interleukin-1 beta induced synthesis of protein kinase C-delta and protein kinase C-epsilon in EL4 thymoma cells: possible involvement of phosphatidylinositol 3-kinase.

PubMed

Varley, C L; Royds, J A; Brown, B L; Dobson, P R

2001-01-01

We present evidence here that the proinflammatory cytokine, interleukin-1 beta (IL-1 beta) stimulates a significant increase in protein kinase C (PKC)-epsilon and PKC-delta protein levels and increases PKC-epsilon, but not PKC-delta, transcripts in EL4 thymoma cells. Incubation of EL4 cells with IL-1 beta induced protein synthesis of PKC-epsilon (6-fold increase) by 7 h and had a biphasic effect on PKC-delta levels with peaks at 4 h (2-fold increase) and 24 h (4-fold increase). At the level of mRNA, PKC-epsilon, but not PKC-delta levels, were induced after incubation of EL4 cells with IL-1 beta. The signalling mechanisms utilized by IL-1 beta to induce the synthesis of these PKC isoforms were investigated. Two phosphatidylinositol (PI) 3-kinase-specific inhibitors, wortmannin and LY294002, inhibited IL-1 beta-induced synthesis of PKC-epsilon. However, the PI 3-kinase inhibitors had little effect on the IL-1 beta-induced synthesis of PKC-delta in these cells. Our results indicate that IL-1 beta induced both PKC-delta and PKC-epsilon expression over different time periods. Furthermore, our evidence suggests that IL-1 beta induction of PKC-epsilon, but not PKC-delta, may occur via the PI 3-kinase pathway. Copyright 2001 S. Karger AG, Basel

Nanomaterial Solutions for the Protection of Insulin Producing Beta Cells

NASA Astrophysics Data System (ADS)

Atchison, Nicole Ann

Islet transplantation is a promising treatment for type 1 diabetes. However, even with the many successes, islet transplantation has yet to reach its full potential. Limited islet sources, loss of cell viability during isolation and culture, and post-transplant graft loss are a few of the issues preventing extensive use of islet transplantation. The application of biomaterial systems to alleviate some of the stresses affecting islet viability has led to improvements in isolation and transplantation outcomes, but problems persist. In this work we approach two distinct issues affecting islet viability; ischemic conditions and immunological attack post-transplant. Ischemic conditions have been linked to a loss of islet graft function and occur during organ preservation, islet isolation and culture, and after islets are transplanted. We show that liposomal delivery of adenosine triphosphate (ATP) to beta cells can limit cell death and loss of function in ischemic conditions. We demonstrate that by functionalizing liposomes with the fibronectin-mimetic peptide PR_b, delivery of liposomes to porcine islets and rat beta cells is increased compared to nontargeted controls. Additionally, liposomes are shown to protect by providing both ATP and lipids to the ischemic cells. The delivery of ATP was investigated here but application of PR_b functionalized liposomes could be extended to other interesting cargos as well. The second area of investigation involves encapsulation of islets with silica nanoparticles to create a permselective barrier. Silica nanoparticles are an interesting material for encapsulation given their ability to be fine-tuned and further functionalized. We demonstrate that size-tunable, fluorescent silica nanoparticles can be assembled layer-by-layer on the surface of cells and that silica nanoparticle encapsulated islets are able to secrete insulin in response to a glucose challenge.

Nicotine promotes cell proliferation via {alpha}7-nicotinic acetylcholine receptor and catecholamine-synthesizing enzymes-mediated pathway in human colon adenocarcinoma HT-29 cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wong, Helen Pui Shan; Yu Le; Lam, Emily Kai Yee

Cigarette smoking has been implicated in colon cancer. Nicotine is a major alkaloid in cigarette smoke. In the present study, we showed that nicotine stimulated HT-29 cell proliferation and adrenaline production in a dose-dependent manner. The stimulatory action of nicotine was reversed by atenolol and ICI 118,551, a {beta}{sub 1}- and {beta}{sub 2}-selective antagonist, respectively, suggesting the role of {beta}-adrenoceptors in mediating the action. Nicotine also significantly upregulated the expression of the catecholamine-synthesizing enzymes [tyrosine hydroxylase (TH), dopamine-{beta}-hydroxylase (D{beta}H) and phenylethanolamine N-methyltransferase]. Inhibitor of TH, a rate-limiting enzyme in the catecholamine-biosynthesis pathway, reduced the actions of nicotine on cell proliferationmore » and adrenaline production. Expression of {alpha}7-nicotinic acetylcholine receptor ({alpha}7-nAChR) was demonstrated in HT-29 cells. Methyllycaconitine, an {alpha}7-nAChR antagonist, reversed the stimulatory actions of nicotine on cell proliferation, TH and D{beta}H expression as well as adrenaline production. Taken together, through the action on {alpha}7-nAChR nicotine stimulates HT-29 cell proliferation via the upregulation of the catecholamine-synthesis pathway and ultimately adrenaline production and {beta}-adrenergic activation. These data reveal the contributory role {alpha}7-nAChR and {beta}-adrenoceptors in the tumorigenesis of colon cancer cells and partly elucidate the carcinogenic action of cigarette smoke on colon cancer.« less

Alpha cells secrete acetylcholine as a non-neuronal paracrine signal priming human beta cell function

PubMed Central

Rodriguez-Diaz, Rayner; Dando, Robin; Jacques-Silva, M. Caroline; Fachado, Alberto; Molina, Judith; Abdulreda, Midhat; Ricordi, Camillo; Roper, Stephen D.; Berggren, Per-Olof; Caicedo, Alejandro

2011-01-01

Acetylcholine is a neurotransmitter that plays a major role in the function of the insulin secreting pancreatic beta cell1,2. Parasympathetic innervation of the endocrine pancreas, the islets of Langerhans, has been shown to provide cholinergic input to the beta cell in several species1,3,4, but the role of autonomic innervation in human beta cell function is at present unclear. Here we show that, in contrast to mouse islets, cholinergic innervation of human islets is sparse. Instead, we find that the alpha cells of the human islet provide paracrine cholinergic input to surrounding endocrine cells. Human alpha cells express the vesicular acetylcholine transporter and release acetylcholine when stimulated with kainate or a lowering in glucose concentration. Acetylcholine secretion by alpha cells in turn sensitizes the beta cell response to increases in glucose concentration. Our results demonstrate that in human islets acetylcholine is a paracrine signal that primes the beta cell to respond optimally to subsequent increases in glucose concentration. We anticipate these results to revise models about neural input and cholinergic signaling in the endocrine pancreas. Cholinergic signaling within the islet represents a potential therapeutic target in diabetes5, highlighting the relevance of this advance to future drug development. PMID:21685896

Early stages in the development of human T, natural killer and thymic dendritic cells.

PubMed

Spits, H; Blom, B; Jaleco, A C; Weijer, K; Verschuren, M C; van Dongen, J J; Heemskerk, M H; Res, P C

1998-10-01

T-cell development is initiated when CD34+ pluripotent stem cells or their immediate progeny leave the bone marrow to migrate to the thymus. Upon arrival in the thymus the stem cell progeny is not yet committed to the T-cell lineage as it has the capability to develop into T, natural killer (NK) and dendritic cells (DC). Primitive hematopoietic progenitor cells in the human thymus express CD34 and lack CD1a. When these progenitor cells develop into T cells they traverse a number of checkpoints. One early checkpoint is the induction of T-cell commitment, which correlates with appearance of CD1a and involves the loss of capacity to develop into NK cells and DC and the initiation of T-cell receptor (TCR) gene rearrangements. Basic helix-loop-helix transcription factors play a role in induction of T-cell commitment. CD1a+CD34+ cells develop into CD4+CD8 alpha+ beta+ cells by upregulating first CD4, followed by CD8 alpha and then CD8 beta. Selection for productive TCR beta gene rearrangements (beta selection) likely occurs in the CD4+CD8 alpha+ beta- and CD4+CD8 alpha+ beta+ populations. Although the T and NK-cell lineages are closely related to each other, NK cells can develop independently of the thymus. The fetal thymus is most likely one site of NK-cell development.

Beta-catenin-mediated transactivation and cell-cell adhesion pathways are important in curcumin (diferuylmethane)-induced growth arrest and apoptosis in colon cancer cells.

PubMed

Jaiswal, Aruna S; Marlow, Benjamin P; Gupta, Nirupama; Narayan, Satya

2002-12-05

The development of nontoxic natural agents with chemopreventive activity against colon cancer is the focus of investigation in many laboratories. Curcumin (feruylmethane), a natural plant product, possesses such chemopreventive activity, but the mechanisms by which it prevents cancer growth are not well understood. In the present study, we examined the mechanisms by which curcumin treatment affects the growth of colon cancer cells in vitro. Results showed that curcumin treatment causes p53- and p21-independent G(2)/M phase arrest and apoptosis in HCT-116(p53(+/+)), HCT-116(p53(-/-)) and HCT-116(p21(-/-)) cell lines. We further investigated the association of the beta-catenin-mediated c-Myc expression and the cell-cell adhesion pathways in curcumin-induced G(2)/M arrest and apoptosis in HCT-116 cells. Results described a caspase-3-mediated cleavage of beta-catenin, decreased transactivation of beta-catenin/Tcf-Lef, decreased promoter DNA binding activity of the beta-catenin/Tcf-Lef complex, and decreased levels of c-Myc protein. These activities were linked with decreased Cdc2/cyclin B1 kinase activity, a function of the G(2)/M phase arrest. The decreased transactivation of beta-catenin in curcumin-treated HCT-116 cells was unpreventable by caspase-3 inhibitor Z-DEVD-fmk, even though the curcumin-induced cleavage of beta-catenin was blocked in Z-DEVD-fmk pretreated cells. The curcumin treatment also induced caspase-3-mediated degradation of cell-cell adhesion proteins beta-catenin, E-cadherin and APC, which were linked with apoptosis, and this degradation was prevented with the caspase-3 inhibitor. Our results suggest that curcumin treatment impairs both Wnt signaling and cell-cell adhesion pathways, resulting in G(2)/M phase arrest and apoptosis in HCT-116 cells.

Granulocyte-macrophage colony-stimulating factor amplification of interleukin-1beta and tumor necrosis factor alpha production in THP-1 human monocytic cells stimulated with lipopolysaccharide of oral microorganisms.

PubMed

Baqui, A A; Meiller, T F; Chon, J J; Turng, B F; Falkler, W A

1998-05-01

Cytokines, including granulocyte-macrophage colony-stimulating factor (GM-CSF), are used to assist in bone marrow recovery during cancer chemotherapy. Interleukin-1beta (IL-1beta) and tumor necrosis factor alpha (TNF-alpha) play important roles in inflammatory processes, including exacerbation of periodontal diseases, one of the most common complications in patients who undergo this therapy. A human monocyte cell line (THP-1) was utilized to investigate IL-1beta and TNF-alpha production following GM-CSF supplementation with lipopolysaccharide (LPS) from two oral microorganisms, Porphyromonas gingivalis and Fusobacterium nucleatum. LPS of P. gingivalis or F. nucleatum was prepared by a phenol-water extraction method and characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and determination of total protein and endotoxin contents. Resting THP-1 cells were treated with LPS of P. gingivalis or F. nucleatum and/or GM-CSF (50 IU/ml) by using different concentrations for various time periods. Production of IL-1beta and TNF-alpha in THP-1 cells was measured by solid-phase enzyme-linked immunosorbent assay. Reverse transcription (RT)-PCR was used to evaluate the gene expression of resting and treated THP-1 cells. IL-1beta was not detected in untreated THP-1 cells. IL-1beta production was, however, stimulated sharply at 4 h. GM-CSF amplified IL-1beta production in THP-1 cells treated with LPS from both oral anaerobes. No IL-1beta-specific mRNA transcript was detected in untreated THP-1 cells. However, IL-1beta mRNA was detected by RT-PCR 2 h after stimulation of THP-1 cells with LPS from both organisms. GM-CSF did not shorten the IL-1beta transcriptional activation time. GM-CSF plus F. nucleatum or P. gingivalis LPS activated THP-1 cells to produce a 1.6-fold increase in TNF-alpha production at 4 h over LPS stimulation alone. These investigations with the in vitro THP-1 model indicate that there may be an increase in the cellular immune response to oral endotoxin following GM-CSF therapy, as evidenced by production of the tissue-reactive cytokines IL-1beta and TNF-alpha.

[The mechanism of vasculogenesis: the critical role of transforming growth factor-beta 1 in the formation of vessel-like structures during the differentiation in vitro of murine embryonic stem cells].

PubMed

Tsung, H C; Yao, Z

1996-09-01

When ES-5 cells were transfected with an exogenous porcine TGF-beta 1 gene, one can obtain clones of genetically modified ES cells with over-expression of the transfected gene. We called the genetically modified ES-5 cells as ES-T cells. When ES-T cells were used to study their differentiation in vitro by all trans-retinoic acid (RA), it was soon noticed that embryoid bodies of ES-T cells can exclusively differentiate into endothelial cells and vessel-like structures, but not in their parent ES-5 cells. The above result is the first indication that the differentiation of tubular structures in embryoid bodies of ES-T cells may somehow be related to TGF-beta 1. To demonstrate further the role of TGF-beta 1 in the formation of vessel-like structures, the cultured ES-5 cells in the presence of added rhTGF-beta 1 were closely followed in the course of their differentiation. We have, thus, demonstrated the promoting effects of exogenous rhTGF-beta 1 in the formation of vessel-like structures, morphologically similar to those structures derived from ES-T6 cells, during the differentiation of ES-5 cells, both in monolayer culture, in three dimensional collagen gel and in embryoid bodies cultured on gelatin-coated tissue culture wells. Addition of suitable amount of anti-TGF-beta 1 monoclonal antibody IgG (TB21) to the culture medium of embryoid bodies of ES-T6 cells could effectively abolish the formation of vessel-like structures induced by retinoic acid. The percentage of the inhibition was very high, giving a figure comparable to that of atypical vessel-like structures formed in the control embryoid bodies from their parent ES-5 cells. The flat epithelial-like cells and round cells differentiated from embryoid bodies of ES-T6 cells were stained rather strongly for laminin and type IV collagen by immunofluorescent procedure. The above results indicate clearly that TGF-beta 1 is a crucial factor in organizing the differentiated derivatives (endothelial-like cells and their immediate progenitor cells) from ES-T6 cells to form vessel-like structures, and that the role of TGF-beta 1 in vasculogenesis might be performed, in part, through the modulation of the composition and organization of the extracellular matrix. In addition, the enhanced expression of bFGF mRNA in derivatives differentiated from both ES-5 cells treated with rhTGF-beta 1 and ES-T6 cells were detected by Northern blot analysis. Thus, aside from its effects on extracellular matrix, TGF-beta 1 might also modulate the bioactivity of bFGF in relation to the growth of vascular endothelial cells in the present system.

Ultrasound-mediated interferon {beta} gene transfection inhibits growth of malignant melanoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamaguchi, Kazuki; Department of Anatomy, Fukuoka University School of Medicine, 7-45-1 Nanakuma, Jonan-ku, Fukuoka City 814-0180; Feril, Loreto B., E-mail: ferilism@yahoo.com

2011-07-22

Highlights: {yields} Successful ultrasound-mediated transfection of melanoma (C32) cells with IFN-{beta} genes both in vitro and in vivo. {yields} Ultrasound-mediated IFN-{beta} transfection inhibited proliferation of melanoma cells in vitro. {yields} Ultrasound-mediated IFN-{beta} transfection inhibited melanoma tumor growth in vivo. -- Abstract: We investigated the effects of ultrasound-mediated transfection (sonotransfection) of interferon {beta} (IFN-{beta}) gene on melanoma (C32) both in vitro and in vivo. C32 cells were sonotransfected with IFN-{beta} in vitro. Subcutaneous C32 tumors in mice were sonicated weekly immediately after intra-tumor injection with IFN-{beta} genes mixed with microbubbles. Successful sonotransfection with IFN-{beta} gene in vitro was confirmed by ELISA,more » which resulted in C32 growth inhibition. In vivo, the growth ratio of tumors transfected with IFN-{beta} gene was significantly lower than the other experimental groups. These results may lead to a new method of treatment against melanoma and other hard-to-treat cancers.« less

hnRNP L regulates differences in expression of mouse integrin alpha2beta1.

PubMed

Cheli, Yann; Kunicki, Thomas J

2006-06-01

There is a 2-fold variation in platelet integrin alpha2beta1 levels among inbred mouse strains. Decreased alpha2beta1 in 4 strains carrying Itga2 haplotype 2 results from decreased affinity of heterogeneous ribonucleoprotein L (hnRNP L) for a 6 CA repeat sequence (CA6) within intron 1. Seven strains bearing haplotype 1 and a 21 CA repeat sequence at this position (CA21) express twice the level of platelet alpha2beta1 and exhibit an equivalent gain of platelet function in vitro. By UV crosslinking and immunoprecipitation, hnRNP L binds more avidly to CA21, relative to CA6. By cell-free, in vitro mRNA splicing, decreased binding of hnRNP L results in decreased splicing efficiency and an increased proportion of alternatively spliced product. The splicing enhancer activity of CA21 in vivo is abolished by prior treatment with hnRNP L-specific siRNA. Thus, decreased surface alpha2beta1 results from decreased Itga2 pre-mRNA splicing regulated by hnRNP L and depends on CA repeat length at a specific site in intron 1.

Antiproliferative properties of toremifene on AIDS-related Kaposi's sarcoma cells.

PubMed

Hong, Angela; Leigh, Bryan R

2002-12-01

Kaposi's sarcoma (KS) is the most common neoplastic apoptosis manifestation of acquired immunodeficiency syndrome. Toremifene is known to upregulate transforming growth factor beta-1 (TGF-beta1), which is a growth-inhibitory factor for KS. We investigated the in vitro effect of toremifene on KS cells. MTT assay was used to measure the growth of four KS cell lines and a human umbilical vein endothelial (HUVE) cell line after incubation with toremifene. Reverse transcription polymerase chain reaction and ELISA were used to measure the level of TGF-beta1. The IC(50) for the KS cells ranged from 2.2 to 3.2 microM, and 80% of the growth inhibition occurred within 24 h. Toremifene enhanced TGF-beta1 mRNA expression, and the level of TGF-beta1 increased from 103 to 473 pg/ml after 48 h of incubation. Toremifene had no effect on the growth of HUVE cells. Toremifene has a specific antiproliferative effect on KS cells. The stimulation of TGF-beta1 production may play a role in the antiproliferative process. Copyright 2002 S. Karger AG, Basel

Culturing INS-1 cells on CDPGYIGSR-, RGD- and fibronectin surfaces improves insulin secretion and cell proliferation.

PubMed

Kuehn, Carina; Dubiel, Evan A; Sabra, Georges; Vermette, Patrick

2012-02-01

Rat insulinoma cells (INS-1), an immortalized pancreatic beta cell line, were cultured on low-fouling carboxymethyl-dextran (CMD) layers bearing fibronectin, the tripeptide Arg-Gly-Asp (RGD) or CDPGYIGSR, a laminin nonapeptide. INS-1 cells were non-adherent on CMD and RGE but adhered to fibronectin- and peptide-coated CMD surfaces and to tissue culture polystyrene (TCPS). On CMD bearing fibronectin and the peptides, INS-1 cells showed higher glucose-stimulated insulin secretion compared to those on TCPS, bare CMD and RGE. INS-1 cells experienced a net cell growth, with the lowest found after 7 days on CMD and the highest on fibronectin. Similarly, cells on RGD and CDPGYIGSR showed lower net growth rates than those on fibronectin. Expression of E-cadherin and integrins αvβ3 and α5 were similar between the conditions, except for α5 expression on fibronectin, RGD and CDPGYIGSR. Larger numbers of Ki-67-positive cells were found on CDPGYIGSR, TCPS, fibronectin and RGD. Cells in all conditions expressed Pdx1. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

A model for the kinetics of homotypic cellular aggregation under static conditions

NASA Technical Reports Server (NTRS)

Neelamegham, S.; Munn, L. L.; Zygourakis, K.; McIntire, L. V. (Principal Investigator)

1997-01-01

We present the formulation and testing of a mathematical model for the kinetics of homotypic cellular aggregation. The model considers cellular aggregation under no-flow conditions as a two-step process. Individual cells and cell aggregates 1) move on the tissue culture surface and 2) collide with other cells (or aggregates). These collisions lead to the formation of intercellular bonds. The aggregation kinetics are described by a system of coupled, nonlinear ordinary differential equations, and the collision frequency kernel is derived by extending Smoluchowski's colloidal flocculation theory to cell migration and aggregation on a two-dimensional surface. Our results indicate that aggregation rates strongly depend upon the motility of cells and cell aggregates, the frequency of cell-cell collisions, and the strength of intercellular bonds. Model predictions agree well with data from homotypic lymphocyte aggregation experiments using Jurkat cells activated by 33B6, an antibody to the beta 1 integrin. Since cell migration speeds and all the other model parameters can be independently measured, the aggregation model provides a quantitative methodology by which we can accurately evaluate the adhesivity and aggregation behavior of cells.

Inhibition of estrogen-responsive gene activation by the retinoid X receptor beta: evidence for multiple inhibitory pathways.

PubMed

Segars, J H; Marks, M S; Hirschfeld, S; Driggers, P H; Martinez, E; Grippo, J F; Brown, M; Wahli, W; Ozato, K

1993-04-01

The retinoid X receptor beta (RXR beta; H-2RIIBP) forms heterodimers with various nuclear hormone receptors and binds multiple hormone response elements, including the estrogen response element (ERE). In this report, we show that endogenous RXR beta contributes to ERE binding activity in nuclear extracts of the human breast cancer cell line MCF-7. To define a possible regulatory role of RXR beta regarding estrogen-responsive transcription in breast cancer cells, RXR beta and a reporter gene driven by the vitellogenin A2 ERE were transfected into estrogen-treated MCF-7 cells. RXR beta inhibited ERE-driven reporter activity in a dose-dependent and element-specific fashion. This inhibition occurred in the absence of the RXR ligand 9-cis retinoic acid. The RXR beta-induced inhibition was specific for estrogen receptor (ER)-mediated ERE activation because inhibition was observed in ER-negative MDA-MB-231 cells only following transfection of the estrogen-activated ER. No inhibition of the basal reporter activity was observed. The inhibition was not caused by simple competition of RXR beta with the ER for ERE binding, since deletion mutants retaining DNA binding activity but lacking the N-terminal or C-terminal domain failed to inhibit reporter activity. In addition, cross-linking studies indicated the presence of an auxiliary nuclear factor present in MCF-7 cells that contributed to RXR beta binding of the ERE. Studies using known heterodimerization partners of RXR beta confirmed that RXR beta/triiodothyronine receptor alpha heterodimers avidly bind the ERE but revealed the existence of another triiodothyronine-independent pathway of ERE inhibition. These results indicate that estrogen-responsive genes may be negatively regulated by RXR beta through two distinct pathways.

Cloning, expression, and characterization of a peculiar choline-binding beta-galactosidase from Streptococcus mitis.

PubMed

Campuzano, Susana; Serra, Beatriz; Llull, Daniel; García, José L; García, Pedro

2009-09-01

A Streptococcus mitis genomic DNA fragment carrying the SMT1224 gene encoding a putative beta-galactosidase was identified, cloned, and expressed in Escherichia coli. This gene encodes a protein 2,411 amino acids long with a predicted molecular mass of 268 kDa. The deduced protein contains an N-terminal signal peptide and a C-terminal choline-binding domain consisting of five consensus repeats, which facilitates the anchoring of the secreted enzyme to the cell wall. The choline-binding capacity of the protein facilitates its purification using DEAE-cellulose affinity chromatography, although its complete purification was achieved by constructing a His-tagged fusion protein. The recombinant protein was characterized as a monomeric beta-galactosidase showing a specific activity of around 2,500 U/mg of protein, with optimum temperature and pH ranges of 30 to 40 degrees C and 6.0 to 6.5, respectively. Enzyme activity is not inhibited by glucose, even at 200 mM, and remains highly stable in solution or immobilized at room temperature in the absence of protein stabilizers. In S. mitis, the enzyme was located attached to the cell surface, but a significant activity was also detected in the culture medium. This novel enzyme represents the first beta-galactosidase having a modular structure with a choline-binding domain, a peculiar property that can also be useful for some biotechnological applications.

HLA-E-expressing pluripotent stem cells escape allogeneic responses and lysis by NK cells

PubMed Central

Gornalusse, Germán G.; Hirata, Roli K.; Funk, Sarah; Riolobos, Laura; Lopes, Vanda S.; Manske, Gabriel; Prunkard, Donna; Colunga, Aric G.; Hanafi, Laïla-Aïcha; Clegg, Dennis O.; Turtle, Cameron; Russell, David W.

2017-01-01

Polymorphisms in the human leukocyte antigen (HLA) class I genes can cause the rejection of pluripotent stem cell (PSC)-derived products in allogeneic recipients. Disruption of the Beta-2 Microglobulin (B2M) gene eliminates surface expression of all class I molecules, but leaves the cells vulnerable to lysis by natural killer (NK) cells. Here we show that this ‘missing self’ response can be prevented by forced expression of minimally polymorphic HLA-E molecules. We use adeno-associated virus (AAV)-mediated gene editing to knock in HLA-E genes at the B2M locus in human PSCs in a manner that confers inducible, regulated, surface expression of HLA-E single-chain dimers (fused to B2M) or trimers (fused to B2M and a peptide antigen), without surface expression of HLA-A, B or C. These HLA-engineered PSCs and their differentiated derivatives are not recognized as allogeneic by CD8+ T cells, do not bind anti-HLA antibodies, and are resistant to NK-mediated lysis. Our approach provides a potential source of universal donor cells for applications where the differentiated derivatives lack HLA class II expression. PMID:28504668

HLA-E-expressing pluripotent stem cells escape allogeneic responses and lysis by NK cells.

PubMed

Gornalusse, Germán G; Hirata, Roli K; Funk, Sarah E; Riolobos, Laura; Lopes, Vanda S; Manske, Gabriel; Prunkard, Donna; Colunga, Aric G; Hanafi, Laïla-Aïcha; Clegg, Dennis O; Turtle, Cameron; Russell, David W

2017-08-01

Polymorphisms in the human leukocyte antigen (HLA) class I genes can cause the rejection of pluripotent stem cell (PSC)-derived products in allogeneic recipients. Disruption of the Beta-2 Microglobulin (B2M) gene eliminates surface expression of all class I molecules, but leaves the cells vulnerable to lysis by natural killer (NK) cells. Here we show that this 'missing-self' response can be prevented by forced expression of minimally polymorphic HLA-E molecules. We use adeno-associated virus (AAV)-mediated gene editing to knock in HLA-E genes at the B2M locus in human PSCs in a manner that confers inducible, regulated, surface expression of HLA-E single-chain dimers (fused to B2M) or trimers (fused to B2M and a peptide antigen), without surface expression of HLA-A, B or C. These HLA-engineered PSCs and their differentiated derivatives are not recognized as allogeneic by CD8 + T cells, do not bind anti-HLA antibodies and are resistant to NK-mediated lysis. Our approach provides a potential source of universal donor cells for applications where the differentiated derivatives lack HLA class II expression.

Tumor evasion of the immune system by converting CD4+CD25- T cells into CD4+CD25+ T regulatory cells: role of tumor-derived TGF-beta.

PubMed

Liu, Victoria C; Wong, Larry Y; Jang, Thomas; Shah, Ali H; Park, Irwin; Yang, Ximing; Zhang, Qiang; Lonning, Scott; Teicher, Beverly A; Lee, Chung

2007-03-01

CD4+CD25+ T regulatory (T(reg)) cells were initially described for their ability to suppress autoimmune diseases in animal models. An emerging interest is the potential role of T(reg) cells in cancer development and progression because they have been shown to suppress antitumor immunity. In this study, CD4+CD25- T cells cultured in conditioned medium (CM) derived from tumor cells, RENCA or TRAMP-C2, possess similar characteristics as those of naturally occurring T(reg) cells, including expression of Foxp3, a crucial transcription factor of T(reg) cells, production of low levels of IL-2, high levels of IL-10 and TGF-beta, and the ability to suppress CD4+CD25- T cell proliferation. Further investigation revealed a critical role of tumor-derived TGF-beta in converting CD4+CD25- T cells into T(reg) cells because a neutralizing Ab against TGF-beta, 1D11, completely abrogated the induction of T(reg) cells. CM from a nontumorigenic cell line, NRP-152, or irradiated tumor cells did not convert CD4+CD25- T cells to T(reg) cells because they produce low levels of TGF-beta in CM. Finally, we observed a reduced tumor burden in animals receiving 1D11. The reduction in tumor burden correlated with a decrease in tumor-derived TGF-beta. Treatment of 1D11 also reduced the conversion of CD4+ T cells into T(reg) cells and subsequent T(reg) cell-mediated suppression of antitumor immunity. In summary, we have demonstrated that tumor cells directly convert CD4+CD25- T cells to T(reg) cells through production of high levels of TGF-beta, suggesting a possible mechanism through which tumor cells evade the immune system.

Stimulation of interleukin-1beta-independent interleukin-6 production in human dental pulp cells by lipopolysaccharide.

PubMed

Hosoya, S; Matsushima, K; Ohbayashi, E; Yamazaki, M; Shibata, Y; Abiko, Y

1996-12-01

Dental pulpal infection is most commonly caused by extensive dental caries. A principal driving force behind pulpal disease response appears to lie in the immune system's response to bacteria. However, the production of interleukin (IL)-1beta and IL-6 in human dental pulp (HDP) cells in response to lipopolysaccharide (LPS) has not been well characterized. We examined IL-1beta and IL-6 production in HDP cells by challenging with LPS from Porphyromonas endodontalis, which is a Gram-negative bacteria found in root canals. Our results presented here showed that when HDP cells were stimulated by LPS, the production of IL-6 always preceded that of IL-1beta. Since the IL-6 production was observed even in the presence of the IL-1beta receptor antagonist, we concluded IL-6 production was independent of the IL-1beta molecule in LPS-stimulated HDP cells. This idea was further supported by the results obtained from RT-PCR experiments, in which IL-6 mRNA, but not IL-1beta mRNA, was present in the RNA preparation isolated from the early stage of cells.

17betaE2 promotes cell proliferation in endometriosis by decreasing PTEN via NFkappaB-dependent pathway.

PubMed

Zhang, Hui; Zhao, Xingbo; Liu, Shu; Li, Jijun; Wen, Zeqing; Li, Mingjiang

2010-04-12

The objective of this study was to explore the mechanism of phosphatase and tensin homolog (PTEN) loss in endometriosis. We found that aberrant PTEN expression and mitogen-activated protein kinases (MAPK)/ERK, phosphoinositide 3-kinase (PI3K)/AKt, and nuclear factor-kappaB (NFkappaB) signaling overactivities coexisted in endometriosis. In vitro, 17beta-estradiol rapidly activated the 3 pathways in endometriotic cells and specific inhibitions on the 3 pathways respectively blocked 17beta-estradiol-induced cell proliferation. 17beta-estradiol suppressed PTEN transcription and expression in endometriotic cells which was abolished by specific NFkappaB inhibition. Total/nuclear PTEN-loss and MAPK/ERK, PI3K/AKt, and NFkappaB signal overactivities coexist in endometriosis. In vitro, 17beta-estradiol can promotes cell proliferation in endometriosis by activating PI3K/AKt pathway via an NFkappaB/PTEN-dependent pathway. For the first time we propose the possibility of the presence of a positive feedback-loop: 17beta-estradiol-->high NFkappaB-->low PTEN-->high PI3K-->high NFkappaB, in endometriosis, which may finally promote the proliferation of ectopic endometrial epithelial cells and in turn contributes to the progression of the disease.

A human beta cell line with drug inducible excision of immortalizing transgenes

PubMed Central

Benazra, Marion; Lecomte, Marie-José; Colace, Claire; Müller, Andreas; Machado, Cécile; Pechberty, Severine; Bricout-Neveu, Emilie; Grenier-Godard, Maud; Solimena, Michele; Scharfmann, Raphaël; Czernichow, Paul; Ravassard, Philippe

2015-01-01

Objectives Access to immortalized human pancreatic beta cell lines that are phenotypically close to genuine adult beta cells, represent a major tool to better understand human beta cell physiology and develop new therapeutics for Diabetes. Here we derived a new conditionally immortalized human beta cell line, EndoC-βH3 in which immortalizing transgene can be efficiently removed by simple addition of tamoxifen. Methods We used lentiviral mediated gene transfer to stably integrate a tamoxifen inducible form of CRE (CRE-ERT2) into the recently developed conditionally immortalized EndoC βH2 line. The resulting EndoC-βH3 line was characterized before and after tamoxifen treatment for cell proliferation, insulin content and insulin secretion. Results We showed that EndoC-βH3 expressing CRE-ERT2 can be massively amplified in culture. We established an optimized tamoxifen treatment to efficiently excise the immortalizing transgenes resulting in proliferation arrest. In addition, insulin expression raised by 12 fold and insulin content increased by 23 fold reaching 2 μg of insulin per million cells. Such massive increase was accompanied by enhanced insulin secretion upon glucose stimulation. We further observed that tamoxifen treated cells maintained a stable function for 5 weeks in culture. Conclusions EndoC βH3 cell line represents a powerful tool that allows, using a simple and efficient procedure, the massive production of functional non-proliferative human beta cells. Such cells are close to genuine human beta cells and maintain a stable phenotype for 5 weeks in culture. PMID:26909308

Bone sialoprotein mediates the tumor cell-targeted prometastatic activity of transforming growth factor beta in a mouse model of breast cancer.

PubMed

Nam, Jeong-Seok; Suchar, Adam M; Kang, Mi-Jin; Stuelten, Christina H; Tang, Binwu; Michalowska, Aleksandra M; Fisher, Larry W; Fedarko, Neal S; Jain, Alka; Pinkas, Jan; Lonning, Scott; Wakefield, Lalage M

2006-06-15

Transforming growth factor betas (TGF-beta) play a dual role in carcinogenesis, functioning as tumor suppressors early in the process, and then switching to act as prometastatic factors in late-stage disease. We have previously shown that high molecular weight TGF-beta antagonists can suppress metastasis without the predicted toxicities. To address the underlying mechanisms, we have used the 4T1 syngeneic mouse model of metastatic breast cancer. Treatment of mice with a monoclonal anti-TGF-beta antibody (1D11) significantly suppressed metastasis of 4T1 cells to the lungs. When metastatic 4T1 cells were recovered from lungs of 1D11-treated and control mice, the most differentially expressed gene was found to be bone sialoprotein (Bsp). Immunostaining confirmed the loss of Bsp protein in 1D11-treated lung metastases, and TGF-beta was shown to regulate and correlate with Bsp expression in vitro. Functionally, knockdown of Bsp in 4T1 cells reduced the ability of TGF-beta to induce local collagen degradation and invasion in vitro, and treatment with recombinant Bsp protected 4T1 cells from complement-mediated lysis. Finally, suppression of Bsp in 4T1 cells reduced metastasis in vivo. We conclude that Bsp is a plausible mediator of at least some of the tumor cell-targeted prometastatic activity of TGF-beta in this model and that Bsp expression in metastases can be successfully suppressed by systemic treatment with anti-TGF-beta antibodies.

Molecular printboards: monolayers of beta-cyclodextrins on silicon oxide surfaces.

PubMed

Onclin, Steffen; Mulder, Alart; Huskens, Jurriaan; Ravoo, Bart Jan; Reinhoudt, David N

2004-06-22

Monolayers of beta-cyclodextrin host molecules have been prepared on SiO2 surfaces. An ordered and stable cyano-terminated monolayer was modified in three consecutive surface reactions. First, the cyanide groups were reduced to their corresponding free amines using Red Al as a reducing agent. Second, 1,4-phenylene diisothiocyanate was used to react with the amine monolayer where it acts as a linking molecule, exposing isothiocyanates that can be derivatized further. Finally, per-6-amino beta-cyclodextrin was reacted with these isothiocyanate functions to yield a monolayer exposing beta-cyclodextrin. All monolayers were characterized by contact angle measurements, ellipsometric thickness measurements, Brewster angle Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry, which indicate the formation of a densely packed cyclodextrin surface. It was demonstrated that the beta-cyclodextrin monolayer could bind suitable guest molecules in a reversible manner. A fluorescent molecule (1), equipped with two adamantyl groups for complexation, was adsorbed onto the host monolayer from solution to form a monolayer of guest molecules. Subsequently, the guest molecules were desorbed from the surface by competition with increasing beta-cyclodextrin concentration in solution. The data were fitted using a model. An intrinsic binding constant of 3.3 +/- 1 x 10(5) M(-1) was obtained, which corresponds well to previously obtained results with a divalent guest molecule on beta-cyclodextrin monolayers on gold. In addition, the number of guest molecules bound to the host surface was determined, and a surface coverage of ca. 30% was found.

Effect of electrical stimulation on beta-adrenergic receptor population and cyclic amp production in chicken and rat skeletal muscle cell cultures

NASA Technical Reports Server (NTRS)

Young, R. B.; Bridge, K. Y.; Strietzel, C. J.

2000-01-01

Expression of the beta-adrenergic receptor (betaAR) and its coupling to cyclic AMP (cAMP) synthesis are important components of the signaling system that controls muscle atrophy and hypertrophy, and the goal of this study was to determine if electrical stimulation in a pattern simulating slow muscle contraction would alter the betaAR response in primary cultures of avian and mammalian skeletal muscle cells. Specifically, chicken skeletal muscle cells and rat skeletal muscle cells that had been grown for 7 d in culture were subjected to electrical stimulation for an additional 2 d at a pulse frequency of 0.5 pulses/sec and a pulse duration of 200 msec. In chicken skeletal muscle cells, the betaAR population was not significantly affected by electrical stimulation; however, the ability of these cells to synthesize cyclic AMP was reduced by approximately one-half. In contrast, the betaAR population in rat muscle cells was increased slightly but not significantly by electrical stimulation, and the ability of these cells to synthesize cyclic AMP was increased by almost twofold. The basal levels of intracellular cyclic AMP in neither rat muscle cells nor chicken muscle cells were affected by electrical stimulation.

SU-E-J-03: A Comprehensive Comparison Between Alpha and Beta Emitters for Cancer Radioimmunotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, C.Y.; Guatelli, S; Oborn, B

2014-06-01

Purpose: The purpose of this study is to perform a comprehensive comparison of the therapeutic efficacy and cytotoxicity of alpha and beta emitters for Radioimmunotherapy (RIT). For each stage of cancer development, specific models were built for the separate objectives of RIT to be addressed:a) kill isolated cancer cells in transit in the lymphatic and vascular circulation,b) regress avascular cell clusters,c) regress tumor vasculature and tumors. Methods: Because of the nature of short range, high LET alpha and long energy beta radiation and heterogeneous antigen expression among cancer cells, the microdosimetric approach is essential for the RIT assessment. Geant4 basedmore » microdosimetric models are developed for the three different stages of cancer progression: cancer cells, cell clusters and tumors. The energy deposition, specific energy resulted from different source distribution in the three models was calculated separately for 4 alpha emitting radioisotopes ({sup 211}At, {sup 213}Bi, {sup 223}Ra and {sup 225}Ac) and 6 beta emitters ({sup 32}P, {sup 33}P, {sup 67}Cu, {sup 90}Y, {sup 131}I and {sup 177}Lu). The cell survival, therapeutic efficacy and cytotoxicity are determined and compared between alpha and beta emitters. Results: We show that internal targeted alpha radiation has advantages over beta radiation for killing isolated cancer cells, regressing small cell clusters and also solid tumors. Alpha particles have much higher dose specificity and potency than beta particles. They can deposit 3 logs more dose than beta emitters to single cells and solid tumor. Tumor control probability relies on deep penetration of radioisotopes to cancer cell clusters and solid tumors. Conclusion: The results of this study provide a quantitative understanding of the efficacy and cytotoxicity of RIT for each stage of cancer development.« less

GLP-1-oestrogen attenuates hyperphagia and protects from beta cell failure in diabetes-prone New Zealand obese (NZO) mice.

PubMed

Schwenk, Robert W; Baumeier, Christian; Finan, Brian; Kluth, Oliver; Brauer, Christine; Joost, Hans-Georg; DiMarchi, Richard D; Tschöp, Matthias H; Schürmann, Annette

2015-03-01

Oestrogens have previously been shown to exert beta cell protective, glucose-lowering effects in mouse models. Therefore, the recent development of a glucagon-like peptide-1 (GLP-1)-oestrogen conjugate, which targets oestrogen into cells expressing GLP-1 receptors, offers an opportunity for a cell-specific and enhanced beta cell protection by oestrogen. The purpose of this study was to compare the effects of GLP-1 and GLP-1-oestrogen during beta cell failure under glucolipotoxic conditions. Male New Zealand obese (NZO) mice were treated with daily s.c. injections of GLP-1 and GLP-1-oestrogen, respectively. Subsequently, the effects on energy homeostasis and beta cell integrity were measured. In order to clarify the targeting of GLP-1-oestrogen, transcription analyses of oestrogen-responsive genes in distinct tissues as well as microarray analyses in pancreatic islets were performed. In contrast to GLP-1, GLP-1-oestrogen significantly decreased food intake resulting in a substantial weight reduction, preserved normoglycaemia, increased glucose tolerance and enhanced beta cell protection. Analysis of hypothalamic mRNA profiles revealed elevated expression of Pomc and Leprb. In livers from GLP-1-oestrogen-treated mice, expression of lipogenic genes was attenuated and hepatic triacylglycerol levels were decreased. In pancreatic islets, GLP-1-oestrogen altered the mRNA expression to a pattern that was similar to that of diabetes-resistant NZO females. However, conventional oestrogen-responsive genes were not different, indicating rather indirect protection of pancreatic beta cells. GLP-1-oestrogen efficiently protects NZO mice against carbohydrate-induced beta cell failure by attenuation of hyperphagia. In this regard, targeted delivery of oestrogen to the hypothalamus by far exceeds the anorexigenic capacity of GLP-1 alone.

Integrin expression by human osteoblasts cultured on degradable polymeric materials applicable for tissue engineered bone.

PubMed

El-Amin, Saadiq F; Attawia, Mohamed; Lu, Helen H; Shah, Asist K; Chang, Richard; Hickok, Noreen J; Tuan, Rocky S; Laurencin, Cato T

2002-01-01

The use of biodegradable polymers in the field of orthopaedic surgery has gained increased popularity, as surgical pins and screws, and as potential biological scaffolds for repairing cartilage and bone defects. One such group of polymers that has gained considerable attention are the polyesters, poly(lactide-co-glycolide) (PLAGA) and polylactic acid (PLA), because of their minimal tissue inflammatory response, favorable biocompatibility and degradation characteristics. The objective of this study was to evaluate human osteoblastic cell adherence and growth on PLAGA and PLA scaffolds by examining integrin receptor (alpha2, alpha3, alpha4, alpha5, alpha6 and beta1) expression. Primary human osteoblastic cells isolated from trabecular bone adhered efficiently to both PLAGA and PLA, with the rate of adherence on PLAGA comparable to that of control tissue culture polystyrene (TCPS), and significantly higher than on PLA polymers at 3, 6 and 12 h. Human osteoblastic phenotypic expression, alkaline phosphatase (ALP) activity was positive on both degradable matrices, whereas osteocalcin levels were significantly higher on cells grown on PLAGA than on PLA composites. Interestingly, the integrin subunits, alpha2, alpha3, alpha4, alpha5, alpha6 and beta1 were all expressed at higher levels by osteoblasts cultured on PLAGA than those on PLA as analyzed by westerns blots and by flow cytometry. Among the integrins, alpha2, beta5 and beta1 showed the greatest difference in levels between the two surfaces. Thus, both PLA and PLAGA support osteoblastic adhesion and its accompanying engagement of integrin receptor and expression of osteocalcin and ALP. However PLAGA consistently appeared to be a better substrate for osteoblastic cells based on these parameters. This study is one of the first to investigate the ability of primary human osteoblastic cells isolated from trabecular bone to adhere to the biodegradable polymers PLAGA and PLA, and to examine the expression of their key adhesion receptors (integrins) on these substrates.

Glucose-regulated protein 78 is an intracellular antiviral factor against hepatitis B virus.

PubMed

Ma, Yan; Yu, Jun; Chan, Henry L Y; Chen, Yang-chao; Wang, Hua; Chen, Ying; Chan, Chu-yan; Go, Minnie Y Y; Tsai, Sau-na; Ngai, Sai-ming; To, Ka-fai; Tong, Joanna H M; He, Qing-Yu; Sung, Joseph J Y; Kung, Hsiang-fu; Cheng, Christopher H K; He, Ming-liang

2009-11-01

Hepatitis B virus (HBV) infection is a global public health problem that plays a crucial role in the pathogenesis of chronic hepatitis, cirrhosis, and hepatocellular carcinoma. However, the pathogenesis of HBV infection and the mechanisms of host-virus interactions are still elusive. In this study, two-dimensional gel electrophoresis and mass spectrometry-based comparative proteomics were applied to analyze the host response to HBV using an inducible HBV-producing cell line, HepAD38. Twenty-three proteins were identified as differentially expressed with glucose-regulated protein 78 (GRP78) as one of the most significantly up-regulated proteins induced by HBV replication. This induction was further confirmed in both HepAD38 and HepG2 cells transfected with HBV-producing plasmids by real time RT-PCR and Western blotting as well as in HBV-infected human liver biopsies by immunohistochemistry. Knockdown of GRP78 expression by RNA interference resulted in a significant increase of both intracellular and extracellular HBV virions in the transient HBV-producing HepG2 cells concomitant with enhanced levels of hepatitis B surface antigen and e antigen in the culture medium. Conversely overexpression of GRP78 in HepG2 cells led to HBV suppression concomitant with induction of the positive regulatory circuit of GRP78 and interferon-beta1 (IFN-beta1). In this connection, the IFN-beta1-mediated 2',5'-oligoadenylate synthetase and RNase L signaling pathway was noted to be activated in GRP78-overexpressing HepG2 cells. Moreover GRP78 was significantly down-regulated in the livers of chronic hepatitis B patients after effective anti-HBV treatment (p = 0.019) as compared with their counterpart pretreatment liver biopsies. In conclusion, the present study demonstrates for the first time that GRP78 functions as an endogenous anti-HBV factor via the IFN-beta1-2',5'-oligoadenylate synthetase-RNase L pathway in hepatocytes. Induction of hepatic GRP78 may provide a novel therapeutic approach in treating HBV infection.

Caveolae are negative regulators of transforming growth factor-beta1 signaling in ureteral smooth muscle cells.

PubMed

Stehr, Maximilian; Estrada, Carlos R; Khoury, Joseph; Danciu, Theodora E; Sullivan, Maryrose P; Peters, Craig A; Solomon, Keith R; Freeman, Michael R; Adam, Rosalyn M

2004-12-01

The mechanisms underlying ureteral cell regulation are largely unknown. Previous studies have identified lipid rafts/caveolae as regulators of growth stimulatory signals in ureteral smooth muscle cells (USMCs). In this study we determined whether growth inhibitory signaling by transforming growth factor-beta1 (TGF-beta1) is also regulated by caveolae in USMC. Expression of components of the TGF-beta1 signaling axis in USMCs was determined by immunoblot and mRNA analyses. Growth regulatory activity of TGF-beta1 was assessed by H-thymidine incorporation. In select experiments caveolae were disrupted reversibly by cholesterol depletion and replenishment prior to TGF-beta1 treatment. TGF-beta1-responsive gene expression was evaluated using the TGF-beta1 responsive promoter-reporter construct 3TP-Lux. USMCs expressed TGF-beta1, types I and II TGF-beta1 receptors, and the effector Smad-2. TGF-beta1 potently inhibited DNA synthesis in USMCs (IC50 60 pM). TGF-beta1 mediated DNA synthesis inhibition was potentiated following the disruption of caveolae by cholesterol depletion. This effect was reversible with membrane cholesterol restoration. TGF-beta1 stimulated gene activity was augmented by caveolae disruption, while caveolae reformation returned promoter activity to baseline levels. TGF-beta1 is a potent growth inhibitor of USMCs and its activity can be enhanced by caveolae ablation. These findings suggest a role for TGF-beta1 in the growth regulation of normal ureteral cells and implicate caveolar membrane domains in the negative regulation of TGF-beta1 signaling. These studies may be relevant to ureteral pathologies that are characterized by smooth muscle dysplasia.

Smad7 induces tumorigenicity by blocking TGF-beta-induced growth inhibition and apoptosis.

PubMed

Halder, Sunil K; Beauchamp, R Daniel; Datta, Pran K

2005-07-01

Smad proteins play a key role in the intracellular signaling of the transforming growth factor beta (TGF-beta) superfamily of extracellular polypeptides that initiate signaling to regulate a wide variety of biological processes. The inhibitory Smad, Smad7, has been shown to function as intracellular antagonists of TGF-beta family signaling and is upregulated in several cancers. To determine the effect of Smad7-mediated blockade of TGF-beta signaling, we have stably expressed Smad7 in a TGF-beta-sensitive, well-differentiated, and non-tumorigenic cell line, FET, that was derived from human colon adenocarcinoma. Smad7 inhibits TGF-beta-induced transcriptional responses by blocking complex formation between Smad 2/3 and Smad4. While Smad7 has no effect on TGF-beta-induced activation of p38 MAPK and ERK, it blocks the phosphorylation of Akt by TGF-beta and enhances TGF-beta-induced phosphorylation of c-Jun. FET cells expressing Smad7 show anchorage-independent growth and enhance tumorigenicity in athymic nude mice. Smad7 blocks TGF-beta-induced growth inhibition by preventing TGF-beta-induced G1 arrest. Smad7 inhibits TGF-beta-mediated downregulation of c-Myc, CDK4, and Cyclin D1, and suppresses the expression of p21(Cip1). As a result, Smad7 inhibits TGF-beta-mediated downregulation of Rb phosphorylation. Furthermore, Smad7 inhibits the apoptosis of these cells. Together, Smad7 may increase the tumorigenicity of FET cells by blocking TGF-beta-induced growth inhibition and by inhibiting apoptosis. Thus, this study provides a mechanism by which a portion of human colorectal tumors may become refractory to tumor-suppressive actions of TGF-beta that might result in increased tumorigenicity.

Estradiol, tamoxifen and ICI 182,780 alter alpha3 and beta1 integrin expression and laminin-1 adhesion in oral squamous cell carcinoma cell cultures.

PubMed

Nelson, Katja; Helmstaedter, Victor; Moreau, Cynthia; Lage, Hermann

2008-01-01

Adhesion molecules such as integrins and extracellular matrix proteins like laminins have been identified to play an important role in cell proliferation, migration and invasion by regulating cell-extracellular matrix interaction in various cancers including oral squamous cell carcinoma (OSCC). In this study, the effect of estradiol (E2), and the E2 antagonists tamoxifen (TAM) and ICI 182,780 (ICI) on the expression of integrins and adhesion to laminin-1 in different OSCC in vitro models was analyzed. TAM and ICI inhibited growth in all OSCC cell lines. Dependent on estrogen receptor (ER) status E2 displayed a significant influence on growth after long-term administration. ICI reduced laminin-1 adhesion in all cell lines. beta1 Integrin transcription is reduced with TAM and E2 and alpha3 cell surface expression with TAM. This study shows that OSCC is estrogen and SERM sensitive and that these compounds can modulate cell-matrix interaction in part by modulating integrin expression and translation. The investigation also confirms that growth is significantly influenced by these adjuvant therapeutics. These data suggest that a greater understanding of basic biology and mechanisms of the ER and its ligands in oral squamous cells is needed to elucidate the use of specific pharmacological agents as therapeutics of anti-tumorigenic pathways.

Cell type-specific regulation of beta2-adrenoceptor mRNA by agonists.

PubMed

Danner, S; Lohse, M J

1997-07-16

Prolonged agonist stimulation of beta2-adrenoceptors results in receptor down-regulation which is often paralleled by a reduction of the corresponding mRNA. In this study, we investigated the agonist-dependent regulation of beta2-adrenoceptor mRNA in DDT1-MF2 smooth muscle cells and C6 glioma cells. In DDT1-MF2 cells the half-life of the mRNA was 12 h in monolayer compared to 2 h in suspension cultures. Under both conditions, the agonist isoproterenol reduced this half-life by a factor of 2. In contrast, in C6 glioma cells isoproterenol had no effect on the mRNA stability, even though it reduced mRNA levels by approximately 50%. Isoproterenol-induced downregulation of beta2-adrenoceptor mRNA was completely blocked in C6 cells by the presence of a protein synthesis inhibitor, while this was not so in DDT1-MF2-cells. These data show that beta2-adrenoceptor downregulation occurs via cell-type specific mechanisms.

Beta-2-microglobulin gene expression is maintained in rainbow trout and Atlantic salmon kept at low temperatures.

PubMed

Kales, Stephen; Parks-Dely, Julie; Schulte, Patricia; Dixon, Brian

2006-08-01

Finfish in the wild are regularly subjected to low temperatures, which have been shown to cause a loss of Major Histocompatibility receptor expression in common carp kept at 6 degrees C. This is similar to what was seen in a mammalian cell line cultured at 26 degrees C. Loss of expression of this critical viral recognition protein may provide one mechanism for the increased frequency of fish diseases at low temperatures. This report demonstrates that unlike carp and mammals, beta(2)m transcript levels in both rainbow trout and Atlantic salmon do not decrease after 10 days at temperatures as low as 2 degrees C. Reverse transcriptase (RT)-PCR indicated that transcript steady-state levels of trout beta(2)m were maintained in both tissues and peripheral blood leucocytes, whether freshly isolated or in primary culture. Polyclonal antibodies raised against a recombinant form of trout beta(2)m, demonstrated cross-reactivity to both rainbow trout and Atlantic salmon protein lysates. Use of these antibodies in western blot analyses indicated that cellular protein levels are also maintained at low temperatures in both species while qualitative epifluorescence analysis of freshly isolated peripheral blood leucocytes indicated persistent cell surface expression of trout beta(2)m even after 10 days at 2 degrees C. Rainbow trout and Atlantic salmon may therefore utilise an alternative mode of immune gene regulation than the common carp and mammals allowing them to maintain viral recognition machinery at low temperatures, possibly due to selection for survival in cold climates.

Association of T-cell reactivity with beta-cell function in recent onset type 1 diabetes patients.

PubMed

Pfleger, Christian; Meierhoff, Guido; Kolb, Hubert; Schloot, Nanette C

2010-03-01

The aim of the current study was to investigate whether autoantigen directed T-cell reactivity relates to beta-cell function during the first 78 weeks after diagnosis of type 1 diabetes. 50 adults and 49 children (mean age 27.3 and 10.9 years respectively) with recent onset type 1 diabetes who participated in a placebo-controlled trial of immune intervention with DiaPep277 were analyzed. Secretion of interferon (IFN)-gamma, interleukin (IL)-5, IL-13 and IL-10 by single peripheral mononuclear cells (PBMC) upon stimulation with islet antigens GAD65, heat shock protein 60 (Hsp60) protein-tyrosine-phosphatase-like-antigen (pIA2) or tetanus toxoid (TT) was determined applying ELISPOT; beta-cell function was evaluated by glucagon stimulated C-peptide. Multivariate regression analysis was applied. In general, number of islet antigen-reactive cells decreased over 78 weeks in both adults and children, whereas reactivity to TT was not reduced. In addition, there was an association between the quality of immune cell responses and beta-cell function. Overall, increased responses by IFN-gamma secreting cells were associated with lower beta-cell function whereas IL-5, IL-13 and IL-10 cytokine responses were positively associated with beta-cell function in adults and children. Essentially, the same results were obtained with three different models of regression analysis. The number of detectable islet-reactive immune cells decreases within 1-2 years after diagnosis of type 1 diabetes. Cytokine production by antigen-specific PBMC reactivity is related to beta-cell function as measured by stimulated C-peptide. Cellular immunity appears to regress soon after disease diagnosis and begin of insulin therapy. Copyright 2009 Elsevier Ltd. All rights reserved.

A kinetic comparison of the processing and secretion of the alpha beta dimer and the uncombined alpha and beta subunits of chorionic gonadotropin synthesized by human choriocarcinoma cells.

PubMed

Peters, B P; Krzesicki, R F; Hartle, R J; Perini, F; Ruddon, R W

1984-12-25

Human choriocarcinoma cells (JAR) synthesize the alpha and beta subunits of the glycoprotein hormone chorionic gonadotropin (hCG) (R.W. Ruddon, C.A. Hanson, A. H. Bryan, G.J. Putterman, E.L. White, F. Perini, K. S. Meade, and P.H. Aldenderfer (1980) J. Biol. Chem. 255, 1000-1007). In addition to the hCG dimer (alpha beta), JAR cells secrete uncombined alpha and beta subunits into the culture medium (L.A. Cole, R.J. Hartle, J.A. Laferla, and R.W. Ruddon (1983) Endocrinology 113, 1176-1178). Pulse-chase studies with [35S]methionine or [3H]mannose were carried out in order to compare free alpha, free beta, and the alpha beta dimer with regard to the kinetics of synthesis, N-linked oligosaccharide processing, and secretion and to determine the kinetics of alpha-beta subunit combination. A panel of three antisera was used to immunoprecipitate directly the free subunits and the alpha beta dimer sequentially from the same cell lysates and culture media. The alpha subunit of hCG was synthesized in a slight molar excess (1.2-1.5-fold) over the beta subunit, and alpha beta dimer was rapidly formed by combination of the intracellular alpha and beta precursors. Dimer formation was already apparent in JAR cells following a 10-min biosynthetic labeling incubation with [35S]methionine. The combination of subunits ceased by 30 min of chase even though 51% of alpha and 44% of beta remained free within the cells. Combination of the alpha and beta precursors had occurred before their N-linked oligosaccharides were processed beyond the Man8GlcNAc2 structure. The initial trimming of glucosyl and mannosyl units from the high-mannose oligosaccharides of the hCG precursors occurred more rapidly for free alpha and CG-alpha than for free beta and CG-beta. JAR cells accumulated alpha precursors bearing mostly Man8GlcNAc2 units and beta precursors bearing Man8GlcNAc2 units that represent the substrates of the rate-limiting step in the secretory pathway. In spite of the fact that their N-linked oligosaccharides were trimmed at different rates, free alpha, free beta, and alpha beta dimer were all secreted into the medium at the same rate, with a half-time of 35 min. The secreted hCG forms were stable in the chase medium between 4 and 8h, indicating that extracellular degradation, combination of free subunits to form dimer, or dissociation of dimer to form free subunits did not occur.(ABSTRACT TRUNCATED AT 400 WORDS)

Phospholipase C-mediated hydrolysis of phosphatidylcholine is a target of transforming growth factor beta 1 inhibitory signals.

PubMed Central

Diaz-Meco, M T; Dominguez, I; Sanz, L; Municio, M M; Berra, E; Cornet, M E; Garcia de Herreros, A; Johansen, T; Moscat, J

1992-01-01

Cell growth and tumor transformation can be restrained in certain cell systems by the action of transforming growth factor beta (TGF-beta). It has been established that the mechanism whereby TGF-beta 1 inhibits cell growth does not interfere with the triggering of early mitogenic signal transduction mechanisms. Phospholipase C-catalyzed hydrolysis of phosphatidylcholine (PC) is a relatively late step in the cascade activated by growth factors. Therefore, conceivably activation of phospholipase C-catalyzed hydrolysis of PC could be the target of TGF-beta 1 action. In the study reported here, we demonstrate that TGF-beta 1 inhibits the coupling of ras p21 to the activation of PC hydrolysis, which appears to be critical for the antiproliferative effects of TGF-beta 1. Images PMID:1309592

Orgyia pseudotsugata baculovirus p10 and polyhedron envelope protein genes: analysis of their relative expression levels and role in polyhedron structure.

PubMed

Gross, C H; Russell, R L; Rohrmann, G F

1994-05-01

To investigate the regulation of p10 and polyhedron envelope protein (PEP) gene expression and their role in polyhedron development, Orgyia pseudotsugata multinucleocapsid nuclear polyhedrosis viruses lacking these genes were constructed. Recombinant viruses were produced, in which the p10 gene, the PEP gene or both genes were disrupted with the beta-glucuronidase (GUS) or beta-galactosidase (lacZ) genes. GUS activity under the control of the PEP protein promoter was observed later in infection and its maximal expression was less than 10% the level for p10 promoter-GUS constructs. Tissues from O. pseudotsugata larvae infected with these recombinants were examined by electron microscopy. Cells from insects infected with the p10- viruses lacked p10-associated fibrillar structures, but fragments of polyhedron envelope-like structures were observed on the surface of some polyhedra. Immunogold labelling of cells infected with the p10-GUS+ virus with an antibody directed against PEP showed that the PEP was concentrated at the surface of polyhedra. Although polyhedra produced by p10 and PEP gene deletion mutants demonstrated what appeared to be a polyhedron envelope by transmission electron microscopy, scanning electron microscopy showed that they had irregular, pitted surfaces that were different from wild-type polyhedra. These data suggested that both p10 and PEP are important for the proper formation of the periphery of polyhedra.

Antiangiogenic activity of semisynthetic biotechnological heparins: low-molecular-weight-sulfated Escherichia coli K5 polysaccharide derivatives as fibroblast growth factor antagonists.

PubMed

Presta, Marco; Oreste, Pasqua; Zoppetti, Giorgio; Belleri, Mirella; Tanghetti, Elena; Leali, Daria; Urbinati, Chiara; Bugatti, Antonella; Ronca, Roberto; Nicoli, Stefania; Moroni, Emanuela; Stabile, Helena; Camozzi, Maura; Hernandez, German Andrés; Mitola, Stefania; Dell'Era, Patrizia; Rusnati, Marco; Ribatti, Domenico

2005-01-01

Low-molecular-weight heparin (LMWH) exerts antitumor activity in clinical trials. The K5 polysaccharide from Escherichia coli has the same structure as the heparin precursor. Chemical and enzymatic modifications of K5 polysaccharide lead to the production of biotechnological heparin-like compounds. We investigated the fibroblast growth factor-2 (FGF2) antagonist and antiangiogenic activity of a series of LMW N,O-sulfated K5 derivatives. Surface plasmon resonance analysis showed that LMW-K5 derivatives bind FGF2, thus inhibiting its interaction with heparin immobilized to a BIAcore sensor chip. Interaction of FGF2 with tyrosine-kinase receptors (FGFRs), heparan sulfate proteoglycans (HSPGs), and alpha(v)beta3 integrin is required for biological response in endothelial cells. Similar to LMWH, LMW-K5 derivatives abrogate the formation of HSPG/FGF2/FGFR ternary complexes by preventing FGF2-mediated attachment of FGFR1-overexpressing cells to HSPG-bearing cells and inhibit FGF2-mediated endothelial cell proliferation. However, LMW-K5 derivatives, but not LMWH, also inhibit FGF2/alpha(v)beta3 integrin interaction and consequent FGF2-mediated endothelial cell sprouting in vitro and angiogenesis in vivo in the chick embryo chorioallantoic membrane. LMW N,O-sulfated K5 derivatives affect both HSPG/FGF2/FGFR and FGF2/alpha(v)beta3 interactions and are endowed with FGF2 antagonist and antiangiogenic activity. These compounds may provide the basis for the design of novel LMW heparin-like angiostatic compounds.

Effect of Doping on beta-Tricalcium Phosphate Bioresorbable Bulk Material and Thin Film Coatings

NASA Astrophysics Data System (ADS)

Abdalla, Suhaila

Magnesium has emerged as a revolutionary biodegradable metal for use as an orthopedic material, it has several advantages over the current metallic materials in use, including eliminating the effects of stress shielding, improving biocompatibility and inhibiting degradation rates, thus removing the requirement of a second surgery for implant removal. Due to the rapid degradation of magnesium, it is necessary to control the corrosion rates of the materials to match the rates of bone healing. This dissertation reports on the effect of doping on the properties of beta-tricalcium phosphate (beta-TCP). It also reports on its application as a thin film coating on magnesium alloys for implant applications. Adding various dopants to beta-TCP significantly influences critical properties. In this study, discs were fabricated in two compositions: (i) undoped beta-TCP, (ii) beta-TCP doped with 1.0 wt % MgO, 0.5 wt % ZnO, and 1.0 wt % TiO2. Films were fabricated from these compositions using the pulsed laser deposition (PLD) technique. These coatings were then characterized for corrosive, hardness, and cytocompatibility. The XRD patterns of the coating confirm the amorphous nature of the films. The presence of the metal oxides in beta-TCP improved ceramic densification. The application of these doped coatings was also found to increase the hardness by 88 %, the modulus of elasticity by 66 %, and improve corrosion resistance of the magnesium alloy substrate; with a 2.4 % improvement in Ecorr and 95 % decrease in icorr. Cell viability was studied using an osteoblast precursor cell line MC3T3-E1 to assure that the biocompatibility of these ceramics was not altered due to the dopants. Long-term biodegradation studies were conducted by measuring weight change and surface microstructure as a function of time in simulated body fluid. The results suggest that these coatings could be used for bioresorbable implants with improved corrosion resistance and increased hardness.

Electrical Stimulation Decreases Coupling Efficiency Between Beta-Adrenergic Receptors and Cyclic AMP Production in Cultured Muscle Cells

NASA Technical Reports Server (NTRS)

Young, R. B.; Bridge, K. Y.

1999-01-01

Electrical stimulation of skeletal muscle cells in culture is an effective way to simulate the effects of muscle contraction and its effects on gene expression in muscle cells. Expression of the beta-adrenergic receptor and its coupling to cyclic AMP synthesis are important components of the signaling system that controls muscle atrophy and hypertrophy, and the goal of this project was to determine if electrical stimulation altered the beta-adrenergic response in muscle cells. Chicken skeletal muscle cells that had been grown for seven days in culture were subjected to electrical stimulation for an additional two days at a pulse frequency of 0.5 pulses/sec and a pulse duration of 200 msec. At the end of this two-day stimulation period, beta-adrenergic receptor population was measured by the binding of tritium-labeled CGP-12177 to muscle cells, and coupling to cAMP synthesis was measured by Radioimmunoassay (RIA) after treating the cells for 10 min with the potent (beta)AR agonist, isoproterenol. The number of beta adrenergic receptors and the basal levels of intracellular cyclic AMP were not affected by electrical stimulation. However, the ability of these cells to synthesize cyclic AMP was reduced by approximately 50%. Thus, an enhanced level of contraction reduces the coupling efficiency of beta-adrenergic receptors for cyclic AMP production.

Increased expression of c-Ski as a co-repressor in transforming growth factor-beta signaling correlates with progression of esophageal squamous cell carcinoma.

PubMed

Fukuchi, Minoru; Nakajima, Masanobu; Fukai, Yasuyuki; Miyazaki, Tatsuya; Masuda, Norihiro; Sohda, Makoto; Manda, Ryokuhei; Tsukada, Katsuhiko; Kato, Hiroyuki; Kuwano, Hiroyuki

2004-03-01

Transforming growth factor-beta (TGF-beta) regulates cell growth inhibition, and inactivation of the TGF-beta signaling pathway contributes to tumor development. In our previous study, altered expression of TGF-beta, TGF-beta-specific receptors and Smad4 was shown to correlate with tumor progression in esophageal squamous cell carcinoma (SCC). These components, however, were maintained normally in some patients with esophageal SCC. In our study, the mechanism by which aggressive esophageal SCC maintains these components was investigated, with particular emphasis on the participation of c-Ski and SnoN as transcriptional co-repressors in TGF-beta signaling. Immunohistochemistry for c-Ski and SnoN was carried out on surgical specimens obtained from 80 patients with esophageal SCC. The expression of c-Ski and SnoN was also studied in 6 established cell lines derived from esophageal SCC and compared to an immortalized human esophageal cell line by Western blotting. High levels of expression of c-Ski, detected immunohistologically, were found to correlate with depth of invasion (p = 0.0080) and pathologic stage (p = 0.0447). There was, however, no significant correlation between expression of SnoN and clinicopathologic characteristics. A significant correlation between c-Ski and TGF-beta expression was observed. Moreover, in patients with TGF-beta negative expression, the survival rates of patients with c-Ski positive expression were significantly lower than those of patients with c-Ski negative expression (p = 0.0486). c-Ski was expressed at a high level in 5 of 6 cell lines derived from esophageal SCC compared to immortalized esophageal keratinocytes. Furthermore, the cyclin-dependent kinase (CDK) inhibitor, p21 that was up-regulated by TGF-beta signaling was expressed at a low level in the 5 cell lines. The expression of c-Ski protein as a transcriptional co-repressor in TGF-beta signaling seems to be correlated with tumor progression of esophageal SCC. Copyright 2003 Wiley-Liss, Inc.

Glucocorticoid Signaling Enhances Expression of Glucose-Sensing Molecules in Immature Pancreatic Beta-Like Cells Derived from Murine Embryonic Stem Cells In Vitro.

PubMed

Ghazalli, Nadiah; Wu, Xiaoxing; Walker, Stephanie; Trieu, Nancy; Hsin, Li-Yu; Choe, Justin; Chen, Chialin; Hsu, Jasper; LeBon, Jeanne; Kozlowski, Mark T; Rawson, Jeffrey; Tirrell, David A; Yip, M L Richard; Ku, Hsun Teresa

2018-06-06

Pluripotent stem cells may serve as an alternative source of beta-like cells for replacement therapy of type 1 diabetes; however, the beta-like cells generated in many differentiation protocols are immature. The maturation of endogenous beta cells involves an increase in insulin expression starting in late gestation and a gradual acquisition of the abilities to sense glucose and secrete insulin by week 2 after birth in mice; however, what molecules regulate these maturation processes are incompletely known. In this study, we aim to identify small molecules that affect immature beta cells. A cell-based assay, using pancreatic beta-like cells derived from murine embryonic stem (ES) cells harboring a transgene containing an insulin 1-promoter driven enhanced green fluorescent protein reporter, was used to screen a compound library (NIH Clinical Collection-003). Cortisone, a glucocorticoid, was among five positive hit compounds. Quantitative reverse transcription-polymerase chain reaction analysis revealed that glucocorticoids enhance the gene expression of not only insulin 1 but also glucose transporter-2 (Glut2; Slc2a2) and glucokinase (Gck), two molecules important for glucose sensing. Mifepristone, a pharmacological inhibitor of glucocorticoid receptor (GR) signaling, reduced the effects of glucocorticoids on Glut2 and Gck expression. The effects of glucocorticoids on ES-derived cells were further validated in immature primary islets. Isolated islets from 1-week-old mice had an increased Glut2 and Gck expression in response to a 4-day treatment of exogenous hydrocortisone in vitro. Gene deletion of GR in beta cells using rat insulin 2 promoter-driven Cre crossed with GR flox/flox mice resulted in a reduced gene expression of Glut2, but not Gck, and an abrogation of insulin secretion when islets were incubated in 0.5 mM d-glucose and stimulated by 17 mM d-glucose in vitro. These results demonstrate that glucocorticoids positively regulate glucose sensors in immature murine beta-like cells.

Hepatitis C virus core protein subverts the antiviral activities of human Kupffer cells.

PubMed

Tu, Zhengkun; Pierce, Robert H; Kurtis, Jonathan; Kuroki, Yoshio; Crispe, I Nicholas; Orloff, Mark S

2010-01-01

Kupffer cells (KC) are important innate immune cells of the liver, functioning as scavenging sinusoidal phagocytes and transducers of pattern recognition signals, including those of toll-like receptors (TLRs). The hepatitis C virus core protein (HCVc) engages TLR2 on peripheral blood monocytes and induces production of multiple inflammatory cytokines. We examined the effects of HCVc on human primary KC functions. KC were isolated from living donor allografts and stimulated with HCVc and/or ligands for TLRs. KC were examined for production of cytokines, expression of programmed death-ligand 1 (PD-L1), secretion of type 1 interferons (IFNs), and expression of the apoptosis-inducing protein tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL). HCVc acts as a ligand for TLR2 on human KC, inducing them to secrete interleukin (IL)-1beta, TNF-alpha, and IL-10 and up-regulate cell surface PD-L1. HCVc blocked TLR3-mediated secretion of IFN-alpha, IFN-beta, and cell surface expression of the cytotoxic molecule TRAIL. Inhibition of phosphoinositide 3 kinase with LY294002 blocked the up-regulation of PD-L1 by TLR ligands and the TLR3-specific induction of TRAIL and type 1 IFNs. KC are intravascular macrophages that are continuously exposed to, and tolerant of, bacterial TLR ligands, which are delivered via the portal circulation. By mimicking a bacterial TLR2 ligand and effectively blocking the TLR3-mediated, double-stranded RNA-induced antiviral response, HCVc might appear to exploit this unique aspect of immunity in the liver. Copyright 2010 AGA Institute. Published by Elsevier Inc. All rights reserved.

The sow endometrium at different stages of the oestrous cycle: studies on morphological changes and infiltration by cells of the immune system.

PubMed

Kaeoket, K; Persson, E; Dalin, A M

2001-01-31

The aim of this study was to investigate the distribution of leukocytes and the morphological changes of the sow endometrium throughout the oestrous cycle. Fifteen crossbred multiparous sows (Swedish Landrace x Swedish Yorkshire), with an average parity number of 3.4 +/- 0.7 (mean +/- S.D.) were used. Blood samples were collected from the jugular vein 1h before slaughter for analyses of oestradiol-17beta and progesterone levels. Uterine samples from the mesometrial side of both horns, taken immediately after slaughter at late dioestrus, prooestrus, oestrus, early dioestrus and dioestrus, were fixed, embedded in plastic resin and stained with toluidine blue. The surface and glandular epithelium as well as subepithelial and glandular connective tissue layers were examined by light microscopy. The significantly highest surface and the glandular epithelium were observed at oestrus and dioestrus, respectively. The largest number of capillaries (underneath the surface epithelium) was found at oestrus. In the surface epithelium, the largest number of intraepithelial lymphocytes (IELs, round nucleus) was found at early dioestrus. The largest number of lymphocytes and macrophages within the glandular epithelium were found at early dioestrus and oestrus, respectively. In the subepithelial connective tissue layer, the most common type of leukocytes during all stages was the lymphocyte. The largest numbers of lymphocytes and neutrophils were found at oestrus while the largest number of eosinophils was found at dioestrus. The dominating cells of the immune system in the connective tissue of the glandular layer were lymphocytes and macrophages. The significantly largest numbers of lymphocytes and plasma cells were found at early dioestrus and dioestrus, respectively. The number of lymphocytes in the connective tissue of the glandular layer and the number of plasma cells in the subepithelial layer were positively correlated with the plasma level of progesterone (P < or = 0.05). The numbers of capillaries and neutrophils in the subepithelial layer underneath the surface epithelium as well as the number of macrophages in both surface and glandular epithelium were positively correlated with the plasma level of oestradiol-17beta (P < or = 0.05). In conclusion, the present study showed a variation in the infiltration and distribution of lymphocytes, neutrophils, eosinophils, macrophages, mast cells and plasma cells in the sow endometrium during different stages of the oestrous cycle. Also morphological parameters (e.g. height of surface and glandular epithelium, capillaries density and degree of oedema) varied throughout the oestrous cycle.

Corrigendum to "The sow endometrium at different stages of the oestrus cycle: studies on morphological changes and infiltration by cells of the immune system." [Anim. Reprod. Sci. 65 (2001) 95-114].

PubMed

Kaeoket, K; Persson, E; Dalin, A-M

2002-09-16

The aim of this study was to investigate the distribution of leukocytes and the morphological changes of the sow endometrium throughout the oestrous cycle. Fifteen crossbred multiparous sows (Swedish Landrace x Swedish Yorkshire), with an average parity number of 3.4+/-0.7 (mean+/-S.D.) were used. Blood samples were collected from the jugular vein 1 h before slaughter for analyses of oestradiol-17beta and progesterone levels. Uterine samples from the mesometrial side of both horns, taken immediately after slaughter at late dioestrus, prooestrus, oestrus, early dioestrus and dioestrus, were fixed, embedded in plastic resin and stained with toluidine blue. The surface and glandular epithelium as well as subepithelial and glandular connective tissue layers were examined by light microscopy (LM). The significantly highest surface and the glandular epithelium were observed at oestrus and dioestrus, respectively. The largest number of capillaries (underneath the surface epithelium) was found at oestrus. In the surface epithelium, the largest number of intraepithelial lymphocytes (IELs, round nucleus) was found at early dioestrus. The largest number of lymphocytes and macrophages within the glandular epithelium were found at early dioestrus and oestrus, respectively. In the subepithelial connective tissue layer, the most common type of leukocytes during all stages was the lymphocyte. The largest numbers of lymphocytes and neutrophils were found at oestrus while the largest number of eosinophils was found at dioestrus. The dominating cells of the immune system in the connective tissue of the glandular layer were lymphocytes and macrophages. The significantly largest numbers of lymphocytes and plasma cells were found at early dioestrus and dioestrus, respectively. The number of lymphocytes in the connective tissue of the glandular layer and the number of plasma cells in the subepithelial layer were positively correlated with the plasma level of progesterone (P < or = 0.05). The numbers of capillaries and neutrophils in the subepithelial layer underneath the surface epithelium as well as the number of macrophages in both surface and glandular epithelium were positively correlated with the plasma level of oestradiol-17beta (P < or = 0.05). In conclusion, the present study showed a variation om the infiltration and distrobution of lymphocytes, neutrophils, eosinophils, macrophages, mast cells, and plasma cells in the sow endometrium during different stages of the oestrous cycle. Also morphological parameters (e.g. height of surface and glandular epithelium, capillaries density and degree of oedema) varied throughout the oestrous cycle. Copyright 2002 Elsevier Science B.V.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campbell, K.S.

Norepinephrine has previously been demonstrated by this laboratory to potentiate the in vitro T-dependent antibody response through the stimulation of {beta}-adrenergic receptors. The role of {beta}-adrenergic receptor subtypes in norepinephrine-induced potentiation of the antibody responses was examined with selective {beta}-adrenergic antagonists. The antagonists were metoprolol ({beta}{sub 1}-selective), ICI 118-551 ({beta}{sub 2}-selective), and propranolol ({beta}-non-selective). Both propranolol and ICI 118-551 blocked norepinephrine-induced potentiation of the antibody response, but metoprolol was ineffective. Receptor binding competition of antagonists with the radioligant, ({sup 3}H)CGP-12177 was examined and results were analyzed with the computer program, LIGAND. Competition by ICI 118-551 identified 75% {beta}{sub 2}- andmore » 25% {beta}{sub 1}-adrenergic receptors on splenic mononuclear cells. Enriched T lymphocytes exhibited 75% {beta}{sub 2}-adrenergic receptors, while enriched B lymphocytes contained 90% {beta}{sub 2}-adrenergic receptors as identified by ICI 118-551. Greater than twice as many total receptors were identified on B lymphocytes than T lymphocytes. A T cell lymphoma contained about 60% {beta}{sub 2}-receptors, while 100% were {beta}{sub 2} receptors on a B cell lymphoma, as assessed by ICI 118-551. Results support a heterogeneous {beta}-adrenergic receptor population on T lymphocytes and a more homogeneous {beta}{sub 2}-population on B lymphocytes.« less

IL-1beta suppresses the formation of osteoclasts by increasing OPG production via an autocrine mechanism involving celecoxib-related prostaglandins in chondrocytes.

PubMed

Watanabe, Yusuke; Namba, Aki; Aida, Yukiko; Honda, Kazuhiro; Tanaka, Hideki; Suzuki, Naoto; Matsumura, Hideo; Maeno, Masao

2009-01-01

Elevated interleukin (IL)-1 concentrations in synovial fluid have been implicated in joint bone and cartilage destruction. Previously, we showed that IL-1beta stimulated the expression of prostaglandin (PG) receptor EP4 via increased PGE(2) production. However, the effect of IL-1beta on osteoclast formation via chondrocytes is unclear. Therefore, we examined the effect of IL-1beta and/or celecoxib on the expression of macrophage colony-stimulating factor (M-CSF), receptor activator of NF-kappaB ligand (RANKL), and osteoprotegerin (OPG) in human chondrocytes, and the indirect effect of IL-1beta on osteoclast-like cell formation using RAW264.7 cells. OPG and RANKL expression increased with IL-1beta; whereas M-CSF expression decreased. Celecoxib blocked the stimulatory effect of IL-1beta. Conditioned medium from IL-1beta-treated chondrocytes decreased TRAP staining in RAW264.7 cells. These results suggest that IL-1beta suppresses the formation of osteoclast-like cells via increased OPG production and decreased M-CSF production in chondrocytes, and OPG production may increase through an autocrine mechanism involving celecoxib-related PGs.

Isoreserpine promotes {beta}-catenin degradation via Siah-1 up-regulation in HCT116 colon cancer cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gwak, Jungsug; Song, Taeyun; Song, Jie-Young

2009-09-25

Aberrant accumulation of intracellular {beta}-catenin in intestinal epithelial cells is a frequent early event during the development of colon cancer. To identify small molecules that decrease the level of intracellular {beta}-catenin, we performed cell-based chemical screening using genetically engineered HEK293 reporter cells to detect compounds that inhibit TOPFlash reporter activity, which was stimulated by Wnt3a-conditioned medium. We found that isoreserpine promoted the degradation of intracellular {beta}-catenin by up-regulation of Siah-1 in HEK293 and HCT116 colon cancer cells. Moreover, isoreserpine repressed the expression of {beta}-catenin/T-cell factor (TCF)-dependent genes, such as cyclin D1 and c-myc, resulting in the suppression of HCT116 cellmore » proliferation. Our findings suggest that isoreserpine can potentially be used as a chemotherapeutic agent against colon cancer.« less

Application of microalgal fucoxanthin for the reduction of colon cancer risk: inhibitory activity of fucoxanthin against beta-glucuronidase and DLD-1 cancer cells.

PubMed

Kawee-Ai, Arthitaya; Kim, Sang Moo

2014-07-01

Intestinal bacterial beta-glucuronidases are capable of retoxifying compounds that have been detoxified by liver glucuronidation and are also known to accelerate colon cancer invasion and metastasis. In this study, fucoxanthin extracted from the microalga Phaeodactylum tricornutum was investigated for its inhibitory activity against Escherichia coli beta-glucuronidase and DLD-1 cancer cells. Fucoxanthin inhibited beta-glucuronidase in a concentration-dependent manner with an IC50 value of 2.32 mM and a mixed inhibition type. Fucoxanthin had more potent inhibitory activity on beta-glucuronidase at 37 degrees C and in alkaline conditions. Fucoxanthin also inhibited the beta-glucuronidase activity of DLD-1 cancer cells at a concentration of 20-50 microM. The presence of beta-glucuronidase and substrate in the medium decreased the inhibitory activity of fucoxanthin against DLD-1 cancer cells. Therefore, microalgal fucoxanthin might prevent colon cancer because of its strong beta-glucuronidase inhibitory activity and could be utilized as a novel functional ingredient of food and pharmaceutical supplements.

Design of retrovirus vectors for transfer and expression of the human. beta. -globin gene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, A.D.; Bender, M.A.; Harris, E.A.S.

1988-11-01

Regulated expression of the human ..beta..-globin gene has been demonstrated in cultured murine erythroleukemia cells and in mice after retrovirus-mediated gene transfer. However, the low titer of recombinant viruses described to date results in relatively inefficient gene transfer, which limits their usefulness for animal studies and for potential gene therapy in humans for diseases involving defective ..beta..-globin genes. The authors found regions that interfered with virus production within intron 2 of the ..beta..-globin gene and on both sides of the gene. The flanking regions could be removed, but intron 2 was required for ..beta..-globin expression. Inclusion of ..beta..-globin introns necessitatesmore » an antisense orientation of the gene within the retrovirus vector. However, they found no effect of the antisense ..beta..-globin transcription on virus production. A region downstream of the ..beta..-globin gene that stimulates expression of the gene in transgenic mice was included in the viruses without detrimental effects on virus titer. Virus titers of over 10/sup 6/ CFU/ml were obtained with the final vector design, which retained the ability to direct regulated expression of human ..beta..-globin in murine erythroleukemia cells. The vector also allowed transfer and expression of the human ..beta..-globin gene in hematopoietic cells (CFU-S cells) in mice.« less

Presence of MUC4 in human milk and at the luminal surfaces of blood vessels.

PubMed

Zhang, Jin; Perez, Aymee; Yasin, Mohammad; Soto, Pedro; Rong, Min; Theodoropoulos, George; Carothers Carraway, Coralie A; Carraway, Kermit L

2005-07-01

MUC4 is a heterodimeric membrane mucin, composed of a mucin subunit ASGP-1 (MUC4alpha) and a transmembrane subunit ASGP-2 (MUC4beta), which has been implicated in the protection of epithelial cell surfaces. Surprisingly, development and characterization of a new monoclonal antibody (mAb), called 1G8, against ASGP-2 demonstrated by immunohistochemistry the presence of MUC4 at the luminal surfaces of blood vessels of both normal tissues and tumors. Muc4 was detected with 1G8 and other Muc4 antibodies in blood vessels from humans, rats and mice. This expression of MUC4 in endothelial cells was confirmed by immunoblotting with 1G8 in human umbilical vein endothelial cells (HUVECs), human iliac artery endothelial cells (HIAECs), and human microvascular endothelial cells (HMVECs). MUC4 could be observed on HUVECs grown on either plastic or Matrigel. Finally, MUC4 expression in the three types of endothelial cell lines was confirmed by reverse transcription-polymerase chain reaction (RT-PCR). These results provide, to our knowledge, the first demonstration of a member of the MUC gene family and membrane mucin in blood vessels. As a luminal surface component, the MUC4 is situated to contribute to the non-adhesive luminal surface and to act as an intrinsic protection and survival factor. (c) 2004 Wiley-Liss, Inc.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burgess, Antony W., E-mail: burgess@ludwig.edu.au; Faux, Maree C.; Layton, Meredith J.

In this brief overview we discuss the association between Wnt signaling and colon cell biology and tumorigenesis. Our current understanding of the role of Apc in the {beta}-catenin destruction complex is compared with potential roles for Apc in cell adhesion and migration. The requirement for phosphorylation in the proteasomal-mediated degradation of {beta}-catenin is contrasted with roles for phospho-{beta}-catenin in the activation of transcription, cell adhesion and migration. The synergy between Myb and {beta}-catenin regulation of transcription in crypt stem cells during Wnt signaling is discussed. Finally, potential effects of growth factor regulatory systems, Apc or truncated-Apc on crypt morphogenesis, stemmore » cell localization and crypt fission are considered.« less

Streptococcal modulation of cellular invasion via TGF-beta1 signaling.

PubMed

Wang, Beinan; Li, Shaoying; Southern, Peter J; Cleary, Patrick P

2006-02-14

Group A Streptococcus (GAS) and other bacterial pathogens are known to interact with integrins as an initial step in a complex pathway of bacterial ingestion by host cells. Efficient GAS invasion depends on the interaction of bound fibronectin (Fn) with integrins and activation of integrin signaling. TGF-beta1 regulates expression of integrins, Fn, and other extracellular matrix proteins, and positively controls the integrin signaling pathway. Therefore, we postulated that TGF-beta1 levels could influence streptococcal invasion of mammalian cells. Pretreatment of HEp-2 cells with TGF-beta1 increased their capacity to ingest GAS when the bacteria expressed fibronectin-binding proteins (M1 or PrtF1). Western blots revealed significant induction of alpha5 integrin and Fn expression by HEp-2 cells in response to TGF-beta1. Increased ingestion of streptococci by these cells was blocked by a specific inhibitor of the TGF-beta1 receptor I and antibodies directed against alpha5 integrin and Fn, indicating that increased invasion depends on TGF-beta1 up-regulation of both the alpha5 integrin and Fn. The capacity of TGF-beta1 to up-regulate integrin expression and intracellular invasion by GAS was reproduced in primary human tonsil fibroblasts, which could be a source of TGF-beta1 in chronically infected tonsils. The relationship between TGF-beta1 and GAS invasion was strengthened by the observation that TGF-beta1 production was stimulated in GAS-infected primary human tonsil fibroblasts. These findings suggest a mechanism by which GAS induce a cascade of changes in mammalian tissue leading to elevated expression of the alpha5beta1 receptor, enhanced invasion, and increased opportunity for survival and persistence in their human host.

Sequence-specific interaction between the disintegrin domain of mouse ADAM 3 and murine eggs: role of beta1 integrin-associated proteins CD9, CD81, and CD98.

PubMed

Takahashi, Y; Bigler, D; Ito, Y; White, J M

2001-04-01

ADAM 3 is a sperm surface glycoprotein that has been implicated in sperm-egg adhesion. Because little is known about the adhesive activity of ADAMs, we investigated the interaction of ADAM 3 disintegrin domains, made in bacteria and in insect cells, with murine eggs. Both recombinant proteins inhibited sperm-egg binding and fusion with potencies similar to that which we recently reported for the ADAM 2 disintegrin domain. Alanine scanning mutagenesis revealed a critical importance for the glutamine at position 7 of the disintegrin loop. Fluorescent beads coated with the ADAM 3 disintegrin domain bound to the egg surface. Bead binding was inhibited by an authentic, but not by a scrambled, peptide analog of the disintegrin loop. Bead binding was also inhibited by the function-blocking anti-alpha6 monoclonal antibody (mAb) GoH3, but not by a nonfunction blocking anti-alpha6 mAb, or by mAbs against either the alphav or beta3 integrin subunits. We also present evidence that in addition to the tetraspanin CD9, two other beta1-integrin-associated proteins, the tetraspanin CD81 as well as the single pass transmembrane protein CD98 are expressed on murine eggs. Antibodies to CD9 and CD98 inhibited in vitro fertilization and binding of the ADAM 3 disintegrin domain. Our findings are discussed in terms of the involvement of multiple sperm ADAMs and multiple egg beta1 integrin-associated proteins in sperm-egg binding and fusion. We propose that an egg surface "tetraspan web" facilitates fertilization and that it may do so by fostering ADAM-integrin interactions.

The emergence of non-cytolytic NK1.1+ T cells in the long-term culture of murine tumour-infiltrating lymphocytes: a possible role of transforming growth factor-beta.

PubMed

Tamada, K; Harada, M; Ito, O; Takenoyama, M; Mori, T; Matsuzaki, G; Nomoto, K

1996-12-01

The mechanism by which murine tumour-infiltrating lymphocytes (TIL) decreased their anti-tumour activity during an in vitro culture with interleukin-2 (IL-2) was investigated. A phenotype analysis revealed that the TIL cultured for 7 days (TIL-d7) were exclusively NKI.1- CD4- CD8+ CD3+ cells and that this population was replaced by natural killer (NK)1.1+ CD4- CD8 CD3+ cells by day 27 (TIL-d27) during the culture of TIL. The TIL-d7 cells showed a cytolytic activity against B16 melanoma, whereas the TIL-d27 cells had lost this activity, suggesting that the decrease in the anti tumour effect of TIL during the culture with IL-2 was due to their populational change. Analysis on the characteristics of the TIL-d27 cells revealed that they expressed skewed T-cell receptor (TCR) V beta 5 and increased mRNA expression of V alpha 14. In addition, they expressed transforming growth factor beta (TGF-beta) mRNA. Interestingly, TGF-beta augmented the proliferation of TIL-d27 cells under the presence of IL-2, but suppressed that of TIL-d7 cells. Moreover, the proliferation of TIL-d27 cells was suppressed by anti-TGF-beta monoclonal antibody. Collectively, these results suggest that, in contrast to its suppressive effect on anti-tumour effector T cells. TGF-beta could be an autocrine growth factor for NKL1.1+ T cells and thereby induce non-cytolytic NK1.1+ T cells in the long-term culture of TIL.

The emergence of non-cytolytic NK1.1+ T cells in the long-term culture of murine tumour-infiltrating lymphocytes: a possible role of transforming growth factor-beta.

PubMed Central

Tamada, K; Harada, M; Ito, O; Takenoyama, M; Mori, T; Matsuzaki, G; Nomoto, K

1996-01-01

The mechanism by which murine tumour-infiltrating lymphocytes (TIL) decreased their anti-tumour activity during an in vitro culture with interleukin-2 (IL-2) was investigated. A phenotype analysis revealed that the TIL cultured for 7 days (TIL-d7) were exclusively NKI.1- CD4- CD8+ CD3+ cells and that this population was replaced by natural killer (NK)1.1+ CD4- CD8 CD3+ cells by day 27 (TIL-d27) during the culture of TIL. The TIL-d7 cells showed a cytolytic activity against B16 melanoma, whereas the TIL-d27 cells had lost this activity, suggesting that the decrease in the anti tumour effect of TIL during the culture with IL-2 was due to their populational change. Analysis on the characteristics of the TIL-d27 cells revealed that they expressed skewed T-cell receptor (TCR) V beta 5 and increased mRNA expression of V alpha 14. In addition, they expressed transforming growth factor beta (TGF-beta) mRNA. Interestingly, TGF-beta augmented the proliferation of TIL-d27 cells under the presence of IL-2, but suppressed that of TIL-d7 cells. Moreover, the proliferation of TIL-d27 cells was suppressed by anti-TGF-beta monoclonal antibody. Collectively, these results suggest that, in contrast to its suppressive effect on anti-tumour effector T cells. TGF-beta could be an autocrine growth factor for NKL1.1+ T cells and thereby induce non-cytolytic NK1.1+ T cells in the long-term culture of TIL. Images Figure 4 Figure 6 PMID:9014832

Induction of TGF-beta1 and TGF-beta1-dependent predominant Th17 differentiation by group A streptococcal infection.

PubMed

Wang, Beinan; Dileepan, Thamotharampillai; Briscoe, Sarah; Hyland, Kendra A; Kang, Johnthomas; Khoruts, Alexander; Cleary, P Patrick

2010-03-30

Recurrent group A Streptococcus (GAS) tonsillitis and associated autoimmune diseases indicate that the immune response to this organism can be ineffective and pathological. TGF-beta1 is recognized as an essential signal for generation of regulatory T cells (Tregs) and T helper (Th) 17 cells. Here, the impact of TGF-beta1 induction on the T-cell response in mouse nasal-associated lymphoid tissue (NALT) following intranasal (i.n.) infections is investigated. ELISA and TGF-beta1-luciferase reporter assays indicated that persistent infection of mouse NALT with GAS sets the stage for TGF-beta1 and IL-6 production, signals required for promotion of a Th17 immune response. As predicted, IL-17, the Th17 signature cytokine, was induced in a TGF-beta1 signaling-dependent manner in single-cell suspensions of both human tonsils and NALT. Intracellular cytokine staining and flow cytometry demonstrated that CD4(+) IL-17(+) T cells are the dominant T cells induced in NALT by i.n. infections. Moreover, naive mice acquired the potential to clear GAS by adoptive transfer of CD4(+) T cells from immunized IL-17A(+)/(+) mice but not cells from IL-17A(-)/(-) mice. These experiments link specific induction of TGF-beta1 by a bacterial infection to an in vivo Th17 immune response and show that this cellular response is sufficient for protection against GAS. The association of a Th17 response with GAS infection reveals a potential mechanism for destructive autoimmune responses in humans.

The Role of Oxidative Stress and Hypoxia in Pancreatic Beta-Cell Dysfunction in Diabetes Mellitus.

PubMed

Gerber, Philipp A; Rutter, Guy A

2017-04-01

Metabolic syndrome is a frequent precursor of type 2 diabetes mellitus (T2D), a disease that currently affects ∼8% of the adult population worldwide. Pancreatic beta-cell dysfunction and loss are central to the disease process, although understanding of the underlying molecular mechanisms is still fragmentary. Recent Advances: Oversupply of nutrients, including glucose and fatty acids, and the subsequent overstimulation of beta cells, are believed to be an important contributor to insulin secretory failure in T2D. Hypoxia has also recently been implicated in beta-cell damage. Accumulating evidence points to a role for oxidative stress in both processes. Although the production of reactive oxygen species (ROS) results from enhanced mitochondrial respiration during stimulation with glucose and other fuels, the expression of antioxidant defense genes is unusually low (or disallowed) in beta cells. Not all subjects with metabolic syndrome and hyperglycemia go on to develop full-blown diabetes, implying an important role in disease risk for gene-environment interactions. Possession of common risk alleles at the SLC30A8 locus, encoding the beta-cell granule zinc transporter ZnT8, may affect cytosolic Zn 2+ concentrations and thus susceptibility to hypoxia and oxidative stress. Loss of normal beta-cell function, rather than total mass, is increasingly considered to be the major driver for impaired insulin secretion in diabetes. Better understanding of the role of oxidative changes, its modulation by genes involved in disease risk, and effects on beta-cell identity may facilitate the development of new therapeutic strategies to this disease. Antioxid. Redox Signal. 26, 501-518.

Hydrogen loading system development and evaluation of tritiated substrates to optimize performance in tritium based betavoltaics

NASA Astrophysics Data System (ADS)

Adams, Thomas E.

State-of-the-art hydrogen loading system onto thin metallic films based on differential pressure in calibrated chambers has been developed for conditions pressures and temperatures up to 69 bar and 500°C, respectively. Experiments on hydrogen loading on to palladium films of thickness 50 and 250 nm were conducted at pressure ranging from 0.2 bar to 10 bar at temperature 310°C. For first time film hydrogen loading was carried out at 1 bar and at room temperature which temperature. Beta flux exiting surface of metal tritide films has been modeled with MC-SET (Monte Carlo Simulation of Electron Trajectories in solids). Surface beta flux simulations have been improved to account for density changes from tritium loading and decay. Simulation results indicate a 300 nm slab of MgT2 has a surface flux three times higher than in ScT2, and six times higher than in TiT2. Commercial betavoltaic cells were tested at different temperature environment for their evaluation and characterization.

Ectopic production of beta-HCG by a maxillary squamous cell carcinoma.

PubMed

Scholl, P D; Jurco, S; Austin, J R

1997-12-01

Paraneoplastic syndromes of the head and neck are rare. Hypercalcemia and leukocytosis have been described. The literature was reviewed, and a case of a squamous cell carcinoma of the maxilla producing beta human chorionic gonadotropin (beta-HCG) is presented. A 47-year-old white man with a T4N1M0 squamous cell carcinoma of the left maxilla was treated with a maxillectomy and neck dissection for an N1 positive neck. After completing his planned radiotherapy, he developed distant metastases, which included an axillary node that stained positive for human beta-HCG. Retrospective review of the primary specimen showed beta-HCG positivity in an anaplastic component of the tumor along with vascular invasion. The first case in the literature of a paraneoplastic syndrome with beta-HCG production in association with squamous cell carcinoma of the maxilla is presented. This case history fits the aggressive nature of beta HCG producing tumors elsewhere in the body.

Heat shock protein 90{beta}: A novel mediator of vitamin D action

DOE Office of Scientific and Technical Information (OSTI.GOV)

Angelo, Giana; Mineral Bioavailability Laboratory, 711 Washington Street, Boston, MA 02111; Lamon-Fava, Stefania

2008-03-14

We investigated the role of Heat shock protein 90 (Hsp90) in vitamin D action in Caco-2 cells using geldanamycin (GA) to block Hsp90 function and RNA interference to reduce Hsp90{beta} expression. When cells were exposed to GA, vitamin D-mediated gene expression and transcriptional activity were inhibited by 69% and 54%, respectively. Gel shift analysis indicated that GA reduced vitamin D-mediated DNA binding activity of the vitamin D receptor (VDR). We tested the specific role of Hsp90{beta} by knocking down its expression with stably expressed short hairpin RNA. Vitamin D-induced gene expression and transcriptional activity were reduced by 90% and 80%,more » respectively, in Hsp90{beta}-deficient cells. Nuclear protein for VDR and RXR{alpha}, its heterodimer partner, were not reduced in Hsp90{beta}-deficient cells. These findings indicate that Hsp90{beta} is needed for optimal vitamin D responsiveness in the enterocyte and demonstrate a specific role for Hsp90{beta} in VDR signaling.« less

Lapped substrate for enhanced backsurface reflectivity in a thermophotovoltaic energy conversion system

DOEpatents

Baldasaro, Paul F; Brown, Edward J; Charache, Greg W; DePoy, David M

2000-01-01

A method for fabricating a thermophotovoltaic energy conversion cell including a thin semiconductor wafer substrate (10) having a thickness (.beta.) calculated to decrease the free carrier absorption on a heavily doped substrate; wherein the top surface of the semiconductor wafer substrate is provided with a thermophotovoltaic device (11), a metallized grid (12) and optionally an antireflective (AR) overcoating; and, the bottom surface (10') of the semiconductor wafer substrate (10) is provided with a highly reflecting coating which may comprise a metal coating (14) or a combined dielectric/metal coating (17).

Lapped substrate for enhanced backsurface reflectivity in a thermophotovoltaic energy conversion system

DOEpatents

Baldasaro, Paul F; Brown, Edward J; Charache, Greg W; DePoy, David M

2000-09-05

A method for fabricating a thermophotovoltaic energy conversion cell including a thin semiconductor wafer substrate (10) having a thickness (.beta.) calculated to decrease the free carrier absorption on a heavily doped substrate; wherein the top surface of the semiconductor wafer substrate is provided with a thermophotovoltaic device (11), a metallized grid (12) and optionally an antireflective (AR) overcoating; and, the bottom surface (10') of the semiconductor wafer substrate (10) is provided with a highly reflecting coating which may comprise a metal coating (14) or a combined dielectric/metal coating (17).

Interferon beta 2/B-cell stimulatory factor type 2 shares identity with monocyte-derived hepatocyte-stimulating factor and regulates the major acute phase protein response in liver cells.

PubMed Central

Gauldie, J; Richards, C; Harnish, D; Lansdorp, P; Baumann, H

1987-01-01

One of the oldest and most preserved of the homeostatic responses of the body to injury is the acute phase protein response associated with inflammation. The liver responds to hormone-like mediators by the increased synthesis of a series of plasma proteins called acute phase reactants. In these studies, we examined the relationship of hepatocyte-stimulating factor derived from peripheral blood monocytes to interferon beta 2 (IFN-beta 2), which has been cloned. Antibodies raised against fibroblast-derived IFN-beta having neutralizing activity against both IFN-beta 1 and -beta 2 inhibited the major hepatocyte-stimulating activity derived from monocytes. Fibroblast-derived mediator elicited the identical stimulated response in human HepG2 cells and primary rat hepatocytes as the monocyte cytokine. Finally, recombinant-derived human B-cell stimulatory factor type 2 (IFN-beta 2) from Escherichia coli induced the synthesis of all major acute phase proteins studied in human hepatoma HepG2 and primary rat hepatocyte cultures. These data demonstrate that monocyte-derived hepatocyte-stimulating factor and IFN-beta 2 share immunological and functional identity and that IFN-beta 2, also known as B-cell stimulatory factor and hybridoma plasmacytoma growth factor, has the hepatocyte as a major physiologic target and thereby is essential in controlling the hepatic acute phase response. Images PMID:2444978

Human dendritic cells produce TGF-beta 1 under the influence of lung carcinoma cells and prime the differentiation of CD4+CD25+Foxp3+ regulatory T cells.

PubMed

Dumitriu, Ingrid E; Dunbar, Donald R; Howie, Sarah E; Sethi, Tariq; Gregory, Christopher D

2009-03-01

Dendritic cells (DCs) have a central role in the development of adaptive immune responses, including antitumor immunity. Factors present in the tumor milieu can alter the maturation of DCs and inhibit their capacity to activate T cells. Using gene expression analysis, we found that human DCs increased the expression of TGF-beta1 transcripts following culture with human lung carcinoma cells (LCCs). These DCs produced increased amounts of TGF-beta1 protein compared with DCs not exposed to tumor cells. LCCs also decreased the expression of CD86 and HLA-DR by immature DCs. Furthermore, LCCs decreased CD86 expression and the production of TNF-alpha and IL-12 p70 by mature DCs. Moreover, LCCs also converted mature DCs into cells producing TGF-beta1. These TGF-beta1-producing DCs were poor at eliciting the activation of naive CD4(+) T cells and sustaining their proliferation and differentiation into Th1 (IFN-gamma(+)) effectors. Instead, TGF-beta1-producing DCs demonstrated an increased ability to generate CD4(+)CD25(+)Foxp3(+) regulatory T cells that suppress the proliferation of T lymphocytes. These results identify a novel mechanism by which the function of human DCs is altered by tumor cells and contributes to the evasion of the immune response.

Grape seed procyanidin extract modulates proliferation and apoptosis of pancreatic beta-cells.

PubMed

Cedó, Lídia; Castell-Auví, Anna; Pallarès, Victor; Blay, Mayte; Ardévol, Anna; Arola, Lluís; Pinent, Montserrat

2013-05-01

Grape seed procyanidin extract (GSPE) modulates glucose homeostasis and insulinemia in several animal models. Under pathological conditions, insulin levels are dependent on pancreatic beta-cell functionality, as well as on the beta-cell mass expansion or apoptosis in the pancreas. In this study, we analysed the effects of GSPE on modulating apoptosis and proliferation in beta-cells. We tested the effects of GSPE in the INS-1E pancreatic beta-cell line, either under basal or altered conditions with high glucose, insulin or palmitate levels. GSPE enhanced the pro-apoptotic effect of high glucose and showed clear antiproliferative effects under high glucose, insulin and palmitate conditions. These antiproliferative effects are likely due to high molecular weight compounds contained in the extract. GSPE also modulated pro- and anti-apoptotic markers in the pancreas of rats fed a cafeteria diet, with the effect depending on the dose of GSPE and duration of treatment. Thus, GSPE is able to modulate apoptosis and proliferation of beta-cells under altered, but not basal, conditions. Copyright © 2012 Elsevier Ltd. All rights reserved.

Langerhans cells beta 2-adrenoceptors: role in migration, cytokine production, Th priming and contact hypersensitivity.

PubMed

Maestroni, Georges J M; Mazzola, Paola

2003-11-01

We showed that norepinephrine (NE) hampers IL-12 and stimulates IL-10 production via adrenoceptors (ARs) in bone marrow-derived dendritic cells (BMDC) influencing their Th priming ability. Others have shown that Langerhans cells (LC) express mRNA for beta1-, beta2- and alpha1(A)-(ARs) and that catecholamines may inhibit the antigen-presenting capability via beta2-ARs. Here, we show that also BMDC express mRNA for beta1-, beta2-, alpha2(A)- and alpha2(C)-ARs. Inhibition of IL-12 is mediated by both beta2- and alpha2(A)-ARs, while stimulation of IL-10 by beta2-ARs only. In addition, LC migration, the contact hypersensitivity response (CHS) and production of IFN-gamma and IL-2 in draining lymph node cells is increased in mice treated topically with the beta2-AR antagonist ICI 118,551 during FITC sensitization. Activation of beta2-ARs in BMDC before adoptive transfer could reduce both migration and CHS response to FITC. Finally, preincubation of BMDC with LPS in presence of the specific beta2-AR agonist salbutamol impaired their chemotactic response to CCL19 and CCL21 and this effect was neutralized by anti-IL-10 mAb. We suggest that the physiological activation of beta2-ARs in DC (LC) results in stimulation of IL-10 which in turn restrains DC (LC) migration influencing antigen presentation and the consequent CHS response.

Wnt/beta-Catenin, Foxa2, and CXCR4 Axis Controls Prostate Cancer Progression

DTIC Science & Technology

2014-07-01

NT1 cells that over-expressing Foxa2. The reason we used NT1 cells for the Foxa2 over-expressing experiments is that NT1 is an AR-expressing... cells . We have also established NT1 cells over-expressing a dominant active beta-catenin. We have characterized these cells . Our research found: 1...expression profiles of control NT1 , NT1 /Foxa2, and NT1 /beta-catenin cells Figure 1. We did RT-PCR to examine the expression of key

Ligand-induced adhesion to activated endothelium and to vascular cell adhesion molecule-1 in lymphocytes transfected with the N-formyl peptide receptor.

PubMed

Honda, S; Campbell, J J; Andrew, D P; Engelhardt, B; Butcher, B A; Warnock, R A; Ye, R D; Butcher, E C

1994-04-15

Binding of FMLP to the neutrophil N-formyl peptide receptor (FPR) transmits signals through pertussis toxin-sensitive G proteins triggering Ca2+ flux, superoxide production, granule exocytosis, and neutrophil aggregation and adhesion involving the beta 2 (CD18) integrins. Expression of the FPR in mouse fibroblasts or human kidney cells has been shown to confer an N-formyl peptide-inducible Ca2+ flux in transfectants. Here we demonstrate that the transfected receptor can also support ligand-induced alterations in cellular adhesion. We established stable transfectants of mouse L1-2 pre-B cells with cDNA for human FPR (L1-2 FPR cells). The transfectants bind N-formyl-Nle-Leu-Phe-Nle-Tyr-Lys-fluorescein with 1.4 x 10(5) sites per cell and a dissociation constant of 3.3 nM. Stimulation with FMLP induces a transient Ca2+ flux. FMLP also triggers adhesion of L1-2 FPR cells to TNF-alpha- or LPS-activated bEnd3 cells (mouse brain-derived endothelial cells) and to purified mouse VCAM-1. Binding is inhibited by Abs to VCAM-1 and to the alpha-chain of its lymphocyte receptor (the alpha 4 beta 1 integrin, VLA-4). Stimulation with FMLP does not induce a change in cell surface expression of alpha 4. Induced adhesion to VCAM-1 is rapid, detectable at the earliest times measurable (30 to 60 s after FMLP addition), and is inhibited by pertussis toxin. We conclude that FPR can mediate integrin activation not only in neutrophils but also in lymphocytes, and can trigger rapid adhesion via lymphocyte alpha 4 beta 1. The adhesion of lymphocytes is critical to their migration and targeting; our results suggest the possibility of manipulating adhesive responses through expression of chemoattractant receptors in lymphoid cells engineered for cellular therapy, allowing targeted adhesion and potentially migration in response to locally administered ligands.

Do immunotherapy and beta cell replacement play a synergistic role in the treatment of type 1 diabetes?

PubMed

Li, Dong-Sheng; Warnock, Garth L; Tu, Han-Jun; Ao, Ziliang; He, Zehua; Lu, Hong; Dai, Long-Jun

2009-10-07

Type 1 diabetes (T1D) is the result of the autoimmune response against pancreatic insulin-producing ss-cells. Its ultimate consequence is beta-cell insufficiency-mediated dysregulation of blood glucose control. In terms of T1D treatment, immunotherapy addresses the cause of T1D, mainly through re-setting the balance between autoimmunity and regulatory mechanisms. Regulatory T cells play an important role in this immune intervention. An alternative T1D treatment is beta-cell replacement, which can reverse the consequence of the disease by replacing destroyed beta-cells in the diabetic pancreas. The applicable insulin-producing cells can be directly obtained from islet transplantation or generated from other cell sources such as autologous adult stem cells, embryonic stem cells, and induced pluripotent stem cells. In this review, we summarize the recent research progress and analyze the possible advantages and disadvantages of these two therapeutic options especially focusing on the potential synergistic effect on T1D treatment. Exploring the optimal combination of immunotherapy and beta-cell replacement will pave the way to the most effective cure for this devastating disease.

Structure of the beta 2 homodimer of bacterial luciferase from Vibrio harveyi: X-ray analysis of a kinetic protein folding trap.

PubMed Central

Thoden, J. B.; Holden, H. M.; Fisher, A. J.; Sinclair, J. F.; Wesenberg, G.; Baldwin, T. O.; Rayment, I.

1997-01-01

Luciferase, as isolated from Vibrio harveyi, is an alpha beta heterodimer. When allowed to fold in the absence of the alpha subunit, either in vitro or in vivo, the beta subunit of enzyme will form a kinetically stable homodimer that does not unfold even after prolonged incubation in 5 M urea at pH 7.0 and 18 degrees C. This form of the beta subunit, arising via kinetic partitioning on the folding pathway, appears to constitute a kinetically trapped alternative to the heterodimeric enzyme (Sinclair JF, Ziegler MM, Baldwin TO. 1994. Kinetic partitioning during protein folding yields multiple native states. Nature Struct Biol 1: 320-326). Here we describe the X-ray crystal structure of the beta 2 homodimer of luciferase from V. harveyi determined and refined at 1.95 A resolution. Crystals employed in the investigational belonged to the orthorhombic space group P2(1)2(1)2(1) with unit cell dimensions of a = 58.8 A, b = 62.0 A, and c = 218.2 A and contained one dimer per asymmetric unit. Like that observed in the functional luciferase alpha beta heterodimer, the major tertiary structural motif of each beta subunit consists of an (alpha/beta)8 barrel (Fisher AJ, Raushel FM, Baldwin TO, Rayment I. 1995. Three-dimensional structure of bacterial luciferase from Vibrio harveyi at 2.4 A resolution. Biochemistry 34: 6581-6586). The root-mean-square deviation of the alpha-carbon coordinates between the beta subunits of the hetero- and homodimers is 0.7 A. This high resolution X-ray analysis demonstrated that "domain" or "loop" swapping has not occurred upon formation of the beta 2 homodimer and thus the stability of the beta 2 species to denaturation cannot be explained in such simple terms. In fact, the subunit:subunit interfaces observed in both the beta 2 homodimer and alpha beta heterodimer are remarkably similar in hydrogen-bonding patterns and buried surface areas. PMID:9007973

The effect of TRAIL molecule on cell viability in in vitro beta cell culture.

PubMed

Tekmen, I; Ozyurt, D; Pekçetin, C; Buldan, Z

2007-06-01

Insulin-dependent diabetes mellitus (IDDM) is an organ-specific autoimmune disorder triggered by autoreactive T cells directed to pancreas beta-cell antigens. In this disorder, more than 90% of beta cells are destroyed. Cell death may be mediated via soluble or membrane-bound cell death ligands. One of these ligands may be tumour necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), a member of the TNF-alpha superfamily. In the present study, we examined whether TRAIL had cytotoxic effects on adult rat pancreas beta cell cultures and INS1-E rat insulinoma cell line cultures or not. In this study, cell destruction models were built with TRAIL concentrations of 10, 100 and 1000 ng. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test was used for evaluating cell viability. It was detected that cell cultures with TRAIL added showed no differences statistically when compared with control cultures containing no toxic additions. These results showed that TRAIL did not have significant cytotoxic effects on pancreas beta cell culture and INS-1E rat insulinoma cell line cultures. Detection of the expression of TRAIL receptors and natural apoptosis inhibitor proteins will be favourable to investigate the resistance mechanisms to TRAIL-induced cell death in this cell culture system.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, Kyungsu; Lee, Kyung-Mi; Yoo, Ji-Hye

Graphical abstract: Schematic diagram of the possible molecular mechanism underlying the inhibition of the Wnt/{beta}-catenin signaling pathway and the induction of G0/G1-phase arrest by gomisins J and N, derived from the fruits of S. chinensis, in HCT116 human colon cancer cells. Highlights: Black-Right-Pointing-Pointer Gomisins J and N inhibited Wnt/{beta}-catenin signaling pathway in HCT116 cells. Black-Right-Pointing-Pointer Gomisins J and N disrupted the binding of {beta}-catenin to specific DNA sequences, TBE. Black-Right-Pointing-Pointer Gomisins J and N inhibited the HCT116 cell proliferation through G0/G1 phase arrest. Black-Right-Pointing-Pointer Gomisins J and N inhibited the expression of Cyc D1, a Wnt/{beta}-catenin target gene. -- Abstract:more » Here, we report that gomisin J and gomisin N, dibenzocyclooctadiene type lignans isolated from Schisandra chinensis, inhibit Wnt/{beta}-catenin signaling in HCT116 cells. Gomisins J and N appear to inhibit Wnt/{beta}-catenin signaling by disrupting the interaction between {beta}-catenin and its specific target DNA sequences (TCF binding elements, TBE) rather than by altering the expression of the {beta}-catenin protein. Gomisins J and N inhibit HCT116 cell proliferation by arresting the cell cycle at the G0/G1 phase. The G0/G1 phase arrest induced by gomisins J and N appears to be caused by a decrease in the expression of Cyclin D1, a representative target gene of the Wnt/{beta}-catenin signaling pathway, as well as Cdk2, Cdk4, and E2F-1. Therefore, gomisins J and N, the novel Wnt/{beta}-catenin inhibitors discovered in this study, may serve as potential agents for the prevention and treatment of human colorectal cancers.« less

Transforming growth factor-beta 1 (TGF-beta1) promotes IL-2 mRNA expression through the up-regulation of NF-kappaB, AP-1 and NF-AT in EL4 cells.

PubMed

Han, S H; Yea, S S; Jeon, Y J; Yang, K H; Kaminski, N E

1998-12-01

Transforming growth factor beta1 (TGF-beta1) has been previously shown to modulate interleukin 2 (IL-2) secretion by activated T-cells. In the present studies, we determined that TGF-beta1 induced IL-2 mRNA expression in the murine T-cell line EL4, in the absence of other stimuli. IL-2 mRNA expression was significantly induced by TGF-beta1 (0.1-1 ng/ml) over a relatively narrow concentration range, which led to the induction of IL-2 secretion. Under identical condition, we examined the effect of TGF-beta1 on the activity of nuclear factor AT (NF-AT), nuclear factor kappaB (NF-kappaB), activator protein-1 (AP-1) and octamer, all of which contribute to the regulation of IL-2 gene expression. Electrophoretic mobility shift assays showed that TGF-beta1 markedly increased NF-AT, NF-kappaB and AP-1 binding to their respective cognate DNA binding sites, whereas octamer binding remained constant, as compared with untreated cells. Employing a reporter gene expression system with p(NF-kappaB)3-CAT, p(NF-AT)3-CAT and p(AP-1)3-CAT, TGF-beta1 treatment of transfected EL4 cells induced a dose-related increase in chloramphenicol acetyltransferase activity that correlated well with the DNA binding profile found in the electrophoretic mobility shift assay studies. These results show that TGF-beta1, in the absence of any additional stimuli, up-regulates the activity of key transcription factors involved in IL-2 gene expression, including NF-AT, NF-kappaB and AP-1, to help promote IL-2 mRNA expression by EL4 cells.

Beta-1,4-glucanase-like protein from the cyanobacterium Synechocystis PCC6803 is a beta-1,3-1,4-glucanase and functions in salt stress tolerance.

PubMed

Tamoi, Masahiro; Kurotaki, Hideki; Fukamizo, Tamo

2007-07-01

In the present study, we characterized the gene (Cyanobase accession number slr0897) designated Ssglc encoding a beta-1,4-glucanase-like protein (SsGlc) from Synechocystis PCC6803. The deduced amino acid sequence for Ssglc showed a high degree of similarity to sequences of GH (glycoside hydrolase) family 9 beta-1,4-glucanases (cellulases) from various sources. Surprisingly, the recombinant protein obtained from the Escherichia coli expression system was able to hydrolyse barley beta-glucan and lichenan (beta-1,3-1,4-glucan), but not cellulose (beta-1,4-glucan), curdlan (beta-1,3-glucan), or laminarin (beta-1,3-1,6-glucan). A 1H-NMR analysis of the enzymatic products revealed that the enzyme hydrolyses the beta-1,4-glycosidic linkage of barley beta-glucan through an inverting mechanism. The data indicated that SsGlc was a novel type of GH9 glucanase which could specifically hydrolyse the beta-1,3-1,4-linkage of glucan. The growth of mutant Synechocystis cells in which the Ssglc gene was disrupted by a kanamycin-resistance cartridge gene was almost the same as that of the wild-type cells under continuous light (40 micromol of photons/m2 per s), a 12 h light (40 micromol of photons/m2 per s)/12 h dark cycle, cold stress (4 degrees C), and high light stress (200 micromol of photons/m2 per s). However, under salt stress (300-450 mM NaCl), growth of the Ssglc-disrupted mutant cells was significantly inhibited as compared with that of the wild-type cells. The Ssglc-disrupted mutant cells showed a decreased rate of O2 consumption and NaHCO3-dependent O2 evolution as compared with the wild-type cells under salt stress. Under osmotic stress (100-400 mM sorbitol), there was no difference in growth between the wild-type and the Ssglc-disrupted mutant cells. These results suggest that SsGlc functions in salt stress tolerance in Synechocystis PCC6803.

ROS signaling, oxidative stress and Nrf2 in pancreatic beta-cell function

PubMed Central

Pi, Jingbo; Zhang, Qiang; Fu, Jingqi; Woods, Courtney G.; Hou, Yongyong; Corkey, Barbara E; Collins, Sheila; Andersen, Melvin E.

2009-01-01

This review focuses on the emerging evidence that reactive oxygen species (ROS) derived from glucose metabolism, such as H2O2, act as metabolic signaling molecules for glucose-stimulated insulin secretion (GSIS) in pancreatic beta-cells. Particular emphasis is placed on the potential inhibitory role of endogenous antioxidants, which rise in response to oxidative stress, in glucose-triggered ROS and GSIS. We propose that cellular adaptive response to oxidative stress challenge, such as nuclear factor E2-related factor 2 (Nrf2)-mediated antioxidant induction, plays paradoxical roles in pancreatic beta-cell function. On the one hand, induction of antioxidant enzymes protects beta-cells from oxidative damage and possible cell death, thus minimizing oxidative damage-related impairment of insulin secretion. On the other hand, the induction of antioxidant enzymes by Nrf2 activation blunts glucose-triggered ROS signaling, thus resulting in reduced GSIS. These two premises are potentially relevant to impairment of beta-cells occurring in the late and early stage of Type 2 diabetes, respectively. In addition, we summarized our recent findings that persistent oxidative stress due to absence of uncoupling protein 2 activates cellular adaptive response which is associated with impaired pancreatic beta-cell function. PMID:19501608

Neuroprotective effect of cannabidiol, a non-psychoactive component from Cannabis sativa, on beta-amyloid-induced toxicity in PC12 cells.

PubMed

Iuvone, Teresa; Esposito, Giuseppe; Esposito, Ramona; Santamaria, Rita; Di Rosa, Massimo; Izzo, Angelo A

2004-04-01

Abstract Alzheimer's disease is widely held to be associated with oxidative stress due, in part, to the membrane action of beta-amyloid peptide aggregates. Here, we studied the effect of cannabidiol, a major non-psychoactive component of the marijuana plant (Cannabis sativa) on beta-amyloid peptide-induced toxicity in cultured rat pheocromocytoma PC12 cells. Following exposure of cells to beta-amyloid peptide (1 micro g/mL), a marked reduction in cell survival was observed. This effect was associated with increased reactive oxygen species (ROS) production and lipid peroxidation, as well as caspase 3 (a key enzyme in the apoptosis cell-signalling cascade) appearance, DNA fragmentation and increased intracellular calcium. Treatment of the cells with cannabidiol (10(-7)-10(-4)m) prior to beta-amyloid peptide exposure significantly elevated cell survival while it decreased ROS production, lipid peroxidation, caspase 3 levels, DNA fragmentation and intracellular calcium. Our results indicate that cannabidiol exerts a combination of neuroprotective, anti-oxidative and anti-apoptotic effects against beta-amyloid peptide toxicity, and that inhibition of caspase 3 appearance from its inactive precursor, pro-caspase 3, by cannabidiol is involved in the signalling pathway for this neuroprotection.

Transient receptor potential channel M5 and phospholipaseC-beta2 colocalizing in zebrafish taste receptor cells.

PubMed

Yoshida, Yuki; Saitoh, Kana; Aihara, Yoshiko; Okada, Shinji; Misaka, Takumi; Abe, Keiko

2007-10-08

In mammals, transient receptor potential (TRP) channel M5 (TRPM5) is coexpressed with phospholipaseC-beta2 (PLC-beta2) in the taste receptor cells, and both PLC-beta2 and TRPM5 are essential elements in the signal transduction of sweet, bitter and umami stimuli. In this study, we identified the zebrafish homologue of TRPM5 (zfTRPM5) and examined its expression in the gustatory system by in-situ hybridization. Using a transgenic zebrafish line that expressed green fluorescent protein under the control of the PLC-beta2 promoter, we showed that zfTRPM5 is expressed in green fluorescent protein-labeled cells of the taste buds. These results demonstrate that zfTRPM5 and PLC-beta2 colocalize in zebrafish taste receptor cells, suggesting their crucial roles in taste signaling via the fish taste receptors.

I-domain of lymphocyte function-associated antigen-1 mediates rolling of polystyrene particles on ICAM-1 under flow.

PubMed

Eniola, A Omolola; Krasik, Ellen F; Smith, Lee A; Song, Gang; Hammer, Daniel A

2005-11-01

In their active state, beta(2)-integrins, such as LFA-1, mediate the firm arrest of leukocytes by binding intercellular adhesion molecules (ICAMs) expressed on endothelium. Although the primary function of LFA-1 is assumed to be the ability to mediate firm adhesion, recent work has shown that LFA-1 can contribute to cell tethering and rolling under hydrodynamic flow, a role previously largely attributed to the selectins. The inserted (I) domain of LFA-1 has recently been crystallized in the wild-type (wt) and locked-open conformations and has been shown to, respectively, support rolling and firm adhesion under flow when expressed in alpha(L)beta(2) heterodimers or as isolated domains on cells. Here, we report results from cell-free adhesion assays where wt I-domain-coated polystyrene particles were allowed to interact with ICAM-1-coated surfaces in shear flow. We show that wt I-domain can independently mediate the capture of particles from flow and support their rolling on ICAM-1 surfaces in a manner similar to how carbohydrate-selectin interactions mediate rolling. Adhesion is specific and blocked by appropriate antibodies. We also show that the rolling velocity of I-domain-coated particles depends on the wall shear stress in flow chamber, I-domain site density on microsphere surfaces, and ICAM-1 site density on substrate surfaces. Furthermore, we show that rolling is less sensitive to wall shear stress and ICAM-1 substrate density at high density of I-domain on the microsphere surface. Computer simulations using adhesive dynamics can recreate bead rolling dynamics and show that the mechanochemical properties of ICAM-1-I-domain interactions are similar to those of carbohydrate-selectin interactions. Understanding the biophysics of adhesion mediated by the I-domain of LFA-1 can elucidate the complex roles this integrin plays in leukocyte adhesion in inflammation.

Proinflammatory effect in whole blood by free soluble bacterial components released from planktonic and biofilm cells.

PubMed

Oscarsson, Jan; Karched, Maribasappa; Thay, Bernard; Chen, Casey; Asikainen, Sirkka

2008-11-27

Aggregatibacter actinomycetemcomitans is an oral bacterium associated with aggressive forms of periodontitis. Increasing evidence points to a link between periodontitis and cardiovascular diseases, however, the underlying mechanisms are poorly understood. This study investigated the pathogenic potential of free-soluble surface material, released from live planktonic and biofilm A. actinomycetemcomitans cells. By employing an ex vivo insert model (filter pore size 20 nm) we demonstrated that the A. actinomycetemcomitans strain D7S and its derivatives, in both planktonic and in biofilm life-form, released free-soluble surface material independent of outer membrane vesicles. This material clearly enhanced the production of several proinflammatory cytokines (IL-1 beta, TNF-alpha, IL-6, IL-8, MIP-1 beta) in human whole blood, as evidenced by using a cytokine antibody array and dissociation-enhanced-lanthanide-fluorescent-immunoassay. In agreement with this, quantitative real-time PCR indicated a concomitant increase in transcription of each of these cytokine genes. Experiments in which the LPS activity was blocked with polymyxin B showed that the stimulatory effect was only partly LPS-dependent, suggesting the involvement of additional free-soluble factors. Consistent with this, MALDI-TOF-MS and immunoblotting revealed release of GroEL-like protein in free-soluble form. Conversely, the immunomodulatory toxins, cytolethal distending toxin and leukotoxin, and peptidoglycan-associated lipoprotein, appeared to be less important, as evidenced by studying strain D7S cdt/ltx double, and pal single mutants. In addition to A. actinomycetemcomitans a non-oral species, Escherichia coli strain IHE3034, tested in the same ex vivo model also released free-soluble surface material with proinflammatory activity. A. actinomycetemcomitans, grown in biofilm and planktonic form, releases free-soluble surface material independent of outer membrane vesicles, which induces proinflammatory responses in human whole blood. Our findings therefore suggest that release of surface components from live bacterial cells could constitute a mechanism for systemic stimulation and be of particular importance in chronic localized infections, such as periodontitis.

Impact of small-molecule glucokinase activator on glucose metabolism and beta-cell mass.

PubMed

Nakamura, Akinobu; Terauchi, Yasuo; Ohyama, Sumika; Kubota, Junko; Shimazaki, Hiroko; Nambu, Tadahiro; Takamoto, Iseki; Kubota, Naoto; Eiki, Junichi; Yoshioka, Narihito; Kadowaki, Takashi; Koike, Takao

2009-03-01

We investigated the effect of glucokinase activator (GKA) on glucose metabolism and beta-cell mass. We analyzed four mouse groups: wild-type mice and beta-cell-specific haploinsufficiency of glucokinase gene (Gck(+/-)) mice on a high-fat (HF) diet. Each genotype was also treated with GKA mixed in the HF diet. Rodent insulinoma cells and isolated islets were used to evaluate beta-cell proliferation by GKA. After 20 wk on the above diets, there were no differences in body weight, lipid profiles, and liver triglyceride content among the four groups. Glucose tolerance was improved shortly after the GKA treatment in both genotypes of mice. beta-Cell mass increased in wild-type mice compared with Gck(+/-) mice, but a further increase was not observed after the administration of GKA in both genotypes. Interestingly, GKA was able to up-regulate insulin receptor substrate-2 (Irs-2) expression in insulinoma cells and isolated islets. The administration of GKA increased 5-bromo-2-deoxyuridine (BrdU) incorporation in insulinoma cells, and 3 d administration of GKA markedly increased BrdU incorporation in mice treated with GKA in both genotypes, compared with those without GKA. In conclusion, GKA was able to chronically improve glucose metabolism for mice on the HF diet. Although chronic GKA administration failed to cause a further increase in beta-cell mass in vivo, GKA was able to increase beta cell proliferation in vitro and with a 3-d administration in vivo. This apparent discrepancy can be explained by a chronic reduction in ambient blood glucose levels by GKA treatment.

The effect of TGF-beta2 on MMP-2 production and activity in highly metastatic human bladder carcinoma cell line 5637.

PubMed

Dehnavi, Ehsan; Soheili, Zahra-Soheila; Samiei, Shahram; Ataei, Zahra; Aryan, Hajar

2009-06-01

Transforming growth factor-beta (TGF-beta) superfamily regulates matrix metalloproteinases (MMP), which intrinsically regulate various cell behaviors leading to metastasis. We investigated the effect of TGF-beta(2) on MMP-2 regulation in human bladder carcinoma cell line 5637. Zymography, ELISA, and real-time polymerase chain reaction revealed that TGF-beta(2) stimulated MMP-2 production, but the transcription of its gene remained unchanged. Wortmannin could not inhibit MMP-2 secretion and activity and conversely the amount of the protein and its enzymatic activity were increased. These data suggest that TGF-beta(2) increased MMP-2 at the posttranscriptional level and this upregulation was independent of phosphatidylinositol 3-kinase signaling pathway.

Effect of low doses beta irradiation on micromechanical properties of surface layer of injection molded polypropylene composite

NASA Astrophysics Data System (ADS)

Manas, David; Manas, Miroslav; Gajzlerova, Lenka; Ovsik, Martin; Kratky, Petr; Senkerik, Vojtěch; Skrobak, Adam; Danek, Michal; Manas, Martin

2015-09-01

The influence of beta radiation on the changes in the structure and selected properties (mechanical and thermal) was proved. Using low doses of beta radiation for 25% glass fiber filled polypropylene and its influence on the changes of micromechanical properties of surface layer has not been studied in detail so far. The specimens of 25% glass fiber filled PP were made by injection molding technology and irradiated by low doses of beta radiation (0, 15 and 33 kGy). The changes in the microstructure and micromechanical properties of surface layer were evaluated using FTIR, SEM, WAXS and instrumented microhardness test. The results of the measurements showed considerable increase in micromechanical properties (indentation hardness, indentation elastic modulus) when low doses of beta radiation are used.

Glucocorticoids Suppress Renal Cell Carcinoma Progression by Enhancing Na,K-ATPase Beta-1 Subunit Expression

PubMed Central

Huynh, Thu P.; Barwe, Sonali P.; Lee, Seung J.; McSpadden, Ryan; Franco, Omar E.; Hayward, Simon W.; Damoiseaux, Robert; Grubbs, Stephen S.; Petrelli, Nicholas J.; Rajasekaran, Ayyappan K.

2015-01-01

Glucocorticoids are commonly used as palliative or chemotherapeutic clinical agents for treatment of a variety of cancers. Although steroid treatment is beneficial, the mechanisms by which steroids improve outcome in cancer patients are not well understood. Na,K-ATPase beta-subunit isoform 1 (NaK-β1) is a cell-cell adhesion molecule, and its expression is down-regulated in cancer cells undergoing epithelial-to mesenchymal-transition (EMT), a key event associated with cancer progression to metastatic disease. In this study, we performed high-throughput screening to identify small molecules that could up-regulate NaK-β1 expression in cancer cells. Compounds related to the glucocorticoids were identified as drug candidates enhancing NaK-β1 expression. Of these compounds, triamcinolone, dexamethasone, and fluorometholone were validated to increase NaK-β1 expression at the cell surface, enhance cell-cell adhesion, attenuate motility and invasiveness and induce mesenchymal to epithelial like transition of renal cell carcinoma (RCC) cells in vitro. Treatment of NaK-β1 knockdown cells with these drug candidates confirmed that these compounds mediate their effects through up-regulating NaK-β1. Furthermore, we demonstrated that these compounds attenuate tumor growth in subcutaneous RCC xenografts and reduce local invasiveness in orthotopically-implanted tumors. Our results strongly indicate that the addition of glucocorticoids in the treatment of RCC may improve outcome for RCC patients by augmenting NaK-β1 cell-cell adhesion function. PMID:25836370

Transplantation of transduced chondrocytes protects articular cartilage from interleukin 1-induced extracellular matrix degradation.

PubMed Central

Baragi, V M; Renkiewicz, R R; Jordan, H; Bonadio, J; Hartman, J W; Roessler, B J

1995-01-01

Gene therapy used in the context of delivering a therapeutic gene(s) to chondrocytes offers a new approach for treating chondrocyte-mediated cartilage degradation associated with various human arthropathies including osteoarthritis. In this study, gene delivery to human osteoarthritis chondrocytes in monolayer culture was demonstrated using two adenoviral vectors (Ad.CMVlacZ and Ad.RSVntlacZ) carrying the Escherichia coli beta-galactosidase marker gene, and a third vector (Ad.RSV hIL-1ra) containing the cDNA for human interleukin-1 receptor antagonist. At an moi of 10(3) plaque-forming units/chondrocyte, > 90% of the infected cells stained positive for E. coli beta-galactosidase activity, indicating a high efficiency of transduction. Genetically modified chondrocytes were then transplanted onto the articular surface of osteoarthritic cartilage organ cultures with and without the underlying subchondral bone. Both in situ staining of the cartilage organ cultures for E. coli beta-galactosidase activity and examination by scanning electron microscopy indicated that the transplanted chondrocytes adhered and integrated into the articular surface and continued to express transgenic protein. Chondrocytes transduced with Ad.RSV hIL-1ra and seeded onto the surface of osteoarthritic cartilage secreted high levels of biologically active IL-1 receptor antagonist. The Ad.RSV hIL-1ra-treated cartilage samples were resistant to IL1-induced proteoglycan degradation over 10 d of sustained organ culture. These data demonstrate that transplantation of transduced chondrocytes onto the articular surface protects cartilage from IL-1-induced extracellular matrix degradation. Images PMID:7593634

beta. -adrenergic relaxation of smooth muscle: differences between cells and tissues

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scheid, C.R.

1987-09-01

The present studies were carried out in an attempt to resolve the controversy about the Na/sup +/ dependence of ..beta..-adrenergic relaxation in smooth muscle. Previous studies on isolated smooth muscle cells from the toad stomach had suggested that at least some of the actions of ..beta..-adrenergic agents, including a stimulatory effect on /sup 45/Ca efflux, were dependent on the presence of a normal transmembrane Na/sup +/ gradient. Studies by other investigators using tissues derived from mammalian sources had suggested that the relaxing effect of ..beta..-adrenergic agents was Na/sup +/ independent. Uncertainty remained as to whether these discrepancies reflected differences betweenmore » cells and tissues or differences between species. Thus, in the present studies, the authors utilized both tissues and cells from the same source, the stomach muscle of the toad Bufo marinus, and assessed the Na/sup +/ dependence of ..beta..-adrenergic relaxation. They found that elimination of a normal Na/sup +/ gradient abolished ..beta..-adrenergic relaxation of isolated cells. In tissues, however, similar manipulations had no effect on relaxation. The reasons for this discrepancy are unclear but do not appear to be attributable to changes in smooth muscle function following enzymatic dispersion. Thus the controversy concerning the mechanisms of ..beta..-adrenergic relaxation may reflect inherent differences between tissues and cells.« less

Contribution of oligosaccharides to protection of the H,K-ATPase beta-subunit against trypsinolysis.

PubMed

Crothers, James M; Asano, Shinji; Kimura, Tohru; Yoshida, Ayumi; Wong, Aline; Kang, Jung Wook; Forte, John G

2004-08-01

The proton-pumping H+,K+-adenosinetriphosphatase (H,K-ATPase), responsible for acid secretion by the gastric parietal cell, faces a harshly acidic environment, with some pepsin from neighboring chief cells, at its luminal surface. Its large catalytic alpha-subunit is mostly oriented cytoplasmically. The smaller beta-subunit (HKbeta), is mainly extracellular, with one transmembrane domain and a small cytoplasmic domain. Seven N-linked oligosaccharides in the extracellular domain of HKbeta are thought to contribute to protection of the H,K-ATPase, since previous work has shown that their complete removal, by peptide N-glycosidase F (PNGase F), greatly increased susceptibility of HKbeta to proteolysis. The possibility of graded protection by different numbers of oligosaccharides was investigated here with the use of mutant HKbeta cDNA, having various N-glycosylation sites mutated (Asn to Gln), transfected into HEK-293 cells. Membrane preparations, two days after transfection, were solubilized in 1% Triton X-100 and subjected to trypsinolysis (pH 8, 37 degrees C, trypsin:protein 1:10-1:25). Relative amounts of HKbeta remaining after 20 min trypsin were determined, after sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and probing of Western blots with an antibody to the HKbeta extracellular domain, by chemiluminescent development of blots and densitometry of resulting films. Maturely glycosylated HKbeta was made significantly more susceptible to trypsin than wild type when at least five oligosaccharides were deleted, while the high-mannose form (pre-beta), from the endoplasmic reticulum, became significantly more susceptible than wild-type pre-beta with removal of only two or more oligosaccharides. For each mutant, and wild type, pre-beta was consistently more susceptible than the mature form. While the number, and kind, of oligosaccharides seem to affect protection for HKbeta against trypsinolysis, other aspects of protein maturation, including proper folding of peptide domains and possible subtle alterations of conformation during Golgi processing, are also likely to contribute to this protection. Copyright 2004 Wiley-VCH Verlag GmbH and Co.

Atypical properties of a conventional calcium channel beta subunit from the platyhelminth Schistosoma mansoni.

PubMed

Salvador-Recatalà, Vicenta; Schneider, Toni; Greenberg, Robert M

2008-03-26

The function of voltage-gated calcium (Cav) channels greatly depends on coupling to cytoplasmic accessory beta subunits, which not only promote surface expression, but also modulate gating and kinetic properties of the alpha1 subunit. Schistosomes, parasitic platyhelminths that cause schistosomiasis, express two beta subunit subtypes: a structurally conventional beta subunit and a variant beta subunit with unusual functional properties. We have previously characterized the functional properties of the variant Cavbeta subunit. Here, we focus on the modulatory phenotype of the conventional Cavbeta subunit (SmCavbeta) using the human Cav2.3 channel as the substrate for SmCavbeta and the whole-cell patch-clamp technique. The conventional Schistosoma mansoni Cavbeta subunit markedly increases Cav2.3 currents, slows macroscopic inactivation and shifts steady state inactivation in the hyperpolarizing direction. However, currents produced by Cav2.3 in the presence of SmCavbeta run-down to approximately 75% of their initial amplitudes within two minutes of establishing the whole-cell configuration. This suppressive effect was independent of Ca2+, but dependent on intracellular Mg2+-ATP. Additional experiments revealed that SmCavbeta lends the Cav2.3/SmCavbeta complex sensitivity to Na+ ions. A mutant version of the Cavbeta subunit lacking the first forty-six amino acids, including a string of twenty-two acidic residues, no longer conferred sensitivity to intracellular Mg2+-ATP and Na+ ions, while continuing to show wild type modulation of current amplitude and inactivation of Cav2.3. The data presented in this article provide insights into novel mechanisms employed by platyhelminth Cavbeta subunits to modulate voltage-gated Ca2+ currents that indicate interactions between the Ca2+ channel complex and chelated forms of ATP as well as Na+ ions. These results have potentially important implications for understanding previously unknown mechanisms by which platyhelminths and perhaps other organisms modulate Ca2+ currents in excitable cells.

Dietary toxins, endoplasmic reticulum (ER) stress and diabetes.

PubMed

Hettiarachchi, Kalindi D; Zimmet, Paul Z; Myers, Mark A

2008-05-01

The incidence of Type 1 diabetes has been increasing at a rate too rapid to be due to changes in genetic risk. Instead changes in environmental factors are the likely culprit. The endoplasmic reticulum (ER) plays an important role in the production of newly synthesized proteins and interference with these processes leads to ER stress. The insulin-producing beta cells are particularly prone to ER stress as a result of their heavy engagement in insulin production. Increasing evidence suggests ER stress is central to initiation and progression of Type 1 diabetes. An early environmental exposure, such as toxins and viral infections, can impart a significant physiological load on beta cells to initiate abnormal processing of proinsulin, ER stress and insulin secretory defects. Release of altered proinsulin from the beta cells early in life may trigger autoimmunity in those with genetic susceptibility leading to cytokine-induced nitric oxide production and so exacerbating ER stress in beta cells, ultimately leading to apoptosis of beta cells and diabetes. Here we suggest that ER stress is an inherent cause of beta cell dysfunction and environmental factors, in particular dietary toxins derived from Streptomyces in infected root vegetables, can impart additional stress that aggravates beta cell death and progression to diabetes. Furthermore, we propose that the increasing incidence of Type 1 diabetes may be accounted for by increased dietary exposure to ER-stress-inducing Streptomyces toxins.

Separation of cell survival, growth, migration, and mesenchymal transdifferentiation effects of fibroblast secretome on tumor cells of head and neck squamous cell carcinoma.

PubMed

Metzler, Veronika Maria; Pritz, Christian; Riml, Anna; Romani, Angela; Tuertscher, Raphaela; Steinbichler, Teresa; Dejaco, Daniel; Riechelmann, Herbert; Dudás, József

2017-11-01

Fibroblasts play a central role in tumor invasion, recurrence, and metastasis in head and neck squamous cell carcinoma. The aim of this study was to investigate the influence of tumor cell self-produced factors and paracrine fibroblast-secreted factors in comparison to indirect co-culture on cancer cell survival, growth, migration, and epithelial-mesenchymal transition using the cell lines SCC-25 and human gingival fibroblasts. Thereby, we particularly focused on the participation of the fibroblast-secreted transforming growth factor beta-1.Tumor cell self-produced factors were sufficient to ensure tumor cell survival and basic cell growth, but fibroblast-secreted paracrine factors significantly increased cell proliferation, migration, and epithelial-mesenchymal transition-related phenotype changes in tumor cells. Transforming growth factor beta-1 generated individually migrating disseminating tumor cell groups or single cells separated from the tumor cell nest, which were characterized by reduced E-cadherin expression. At the same time, transforming growth factor beta-1 inhibited tumor cell proliferation under serum-starved conditions. Neutralizing transforming growth factor beta antibody reduced the cell migration support of fibroblast-conditioned medium. Transforming growth factor beta-1 as a single factor was sufficient for generation of disseminating tumor cells from epithelial tumor cell nests, while other fibroblast paracrine factors supported tumor nest outgrowth. Different fibroblast-released factors might support tumor cell proliferation and invasion, as two separate effects.

The physiology of rodent beta-cells in pancreas slices.

PubMed

Rupnik, M

2009-01-01

Beta-cells in pancreatic islets form complex syncytia. Sufficient cell-to-cell electrical coupling seems to ensure coordinated depolarization pattern and insulin release that can be further modulated by rich innervation. The complex structure and coordinated action develop after birth during fast proliferation of the endocrine tissue. These emergent properties can be lost due to various reasons later in life and can lead to glucose intolerance and diabetes mellitus. Pancreas slice is a novel method of choice to study the physiology of beta-cells still embedded in their normal cellulo-social context. I present major advantages, list drawbacks and provide an overview on recent advances in our understanding of the physiology of beta-cells using the pancreas slice approach.

Endoglin inhibits ERK-induced c-Myc and cyclin D1 expression to impede endothelial cell proliferation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pan, Christopher C.; Bloodworth, Jeffrey C.; Mythreye, Karthikeyan

2012-08-03

Highlights: Black-Right-Pointing-Pointer Endoglin inhibits ERK activation in endothelial cells. Black-Right-Pointing-Pointer Endoglin is a regulator of c-Myc and cyclin D1 expression. Black-Right-Pointing-Pointer {beta}-arrestin2 interaction with endoglin is required for ERK/c-Myc repression. Black-Right-Pointing-Pointer Endoglin impedes cellular proliferation by targeting ERK-induced mitogenic signaling. -- Abstract: Endoglin is an endothelial-specific transforming growth factor beta (TGF-{beta}) co-receptor essential for angiogenesis and vascular remodeling. Endoglin regulates a wide range of cellular processes, including cell adhesion, migration, and proliferation, through TGF-{beta} signaling to canonical Smad and Smad-independent pathways. Despite its overall pro-angiogenic role in the vasculature, the underlying mechanism of endoglin action is poorly characterized. We previouslymore » identified {beta}-arrestin2 as a binding partner that causes endoglin internalization from the plasma membrane and inhibits ERK signaling towards endothelial migration. In the present study, we examined the mechanistic role of endoglin and {beta}-arrestin2 in endothelial cell proliferation. We show that endoglin impedes cell growth through sustained inhibition of ERK-induced c-Myc and cyclin D1 expression in a TGF-{beta}-independent manner. The down-regulation of c-Myc and cyclin D1, along with growth-inhibition, are reversed when the endoglin/{beta}-arrestin2 interaction is disrupted. Given that TGF-{beta}-induced Smad signaling potently represses c-Myc in most cell types, our findings here show a novel mechanism by which endoglin augments growth-inhibition by targeting ERK and key downstream mitogenic substrates.« less

Beta-catenin regulates vitamin C biosynthesis and cell survival in murine liver.

PubMed

Nejak-Bowen, Kari N; Zeng, Gang; Tan, Xinping; Cieply, Benjamin; Monga, Satdarshan P

2009-10-09

Because the Wnt/beta-catenin pathway plays multiple roles in liver pathobiology, it is critical to identify gene targets that mediate such diverse effects. Here we report a novel role of beta-catenin in controlling ascorbic acid biosynthesis in murine liver through regulation of expression of regucalcin or senescence marker protein 30 and L-gulonolactone oxidase. Reverse transcription-PCR, Western blotting, and immunohistochemistry demonstrate decreased regucalcin expression in beta-catenin-null livers and greater expression in beta-catenin overexpressing transgenic livers, HepG2 hepatoma cells (contain constitutively active beta-catenin), regenerating livers, and in hepatocellular cancer tissues that exhibit beta-catenin activation. Interestingly, coprecipitation and immunofluorescence studies also demonstrate an association of beta-catenin and regucalcin. Luciferase reporter and chromatin immunoprecipitation assays verified a functional TCF-4-binding site located between -163 and -157 (CTTTGCA) on the regucalcin promoter to be critical for regulation by beta-catenin. Significantly lower serum ascorbate levels were observed in beta-catenin knock-out mice secondary to decreased expression of regucalcin and also of L-gulonolactone oxidase, the penultimate and last (also rate-limiting) steps in the synthesis of ascorbic acid, respectively. These mice also show enhanced basal hepatocyte apoptosis. To test if ascorbate deficiency secondary to beta-catenin loss and regucalcin decrease was contributing to apoptosis, beta-catenin-null hepatocytes or regucalcin small interfering RNA-transfected HepG2 cells were cultured, which exhibited significant apoptosis that was alleviated by the addition of ascorbic acid. Thus, through regucalcin and L-gulonolactone oxidase expression, beta-catenin regulates vitamin C biosynthesis in murine liver, which in turn may be one of the mechanisms contributing to the role of beta-catenin in cell survival.