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The Role of NKT Cells in Tumor Immunity

PubMed Central

Terabe, Masaki; Berzofsky, Jay A.

2009-01-01

NKT cells are a relatively newly recognized member of the immune community, with profound effects on the rest of the immune system despite their small numbers. They are true T cells with a T cell receptor (TCR), but unlike conventional T cells that detect peptide antigens presented by conventional major histocompatibility (MHC) molecules, NKT cells recognize lipid antigens presented by CD1d, a non-classical MHC molecule. As members of both the innate and adaptive immune systems, they bridge the gap between these, and respond rapidly to set the tone for subsequent immune responses. They fill a unique niche in providing the immune system a cellular arm to recognize lipid antigens. They play both effector and regulatory roles in infectious and autoimmune diseases. Furthermore, subsets of NKT cells can play distinct and sometimes opposing roles. In cancer, type I NKT cells, defined by their invariant TCR using Vα14Jα18 in mice and Vα24Jα18 in humans, are mostly protective, by producing interferon-γ to activate NK and CD8+ T cells and by activating dendritic cells to make IL-12. In contrast, type II NKT cells, characterized by more diverse TCRs recognizing lipids presented by CD1d, primarily inhibit tumor immunity. Moreover, type I and type II NKT cells counter-regulate each other, forming a new immunoregulatory axis. Because NKT cells respond rapidly, the balance along this axis can greatly influence other immune responses that follow. Therefore, learning to manipulate the balance along the NKT regulatory axis may be critical to devising successful immunotherapies for cancer. PMID:19055947

Macrophages as IL-25/IL-33-responsive cells play an important role in the induction of type 2 immunity

USDA-ARS?s Scientific Manuscript database

Th2 immunity is essential for the host protection against nematode infection, while detrimental in allergic inflammation or asthma. Although many of the details regarding the cellular and molecular events in Th2 immunity have been described, the specific cell types and effector molecules involved i...

[Polyamines and cell growth: specific aspects in Amoeba proteus and in certain cancer cell lines].

PubMed

Dubois, J; Schenkel, E; Hanocq, M

1995-01-01

The differences between the metabolic schemes of polyamines can be the starting point to investigate the discovery of new antiparasitic or anticancer drugs which would be cell type specific. The studies, which were undertaken with the P388 cancer cells and Amoeba proteus, have shown that the pool of polyamine was very different in both cell types. Moreover, the cytotoxicity of putrescine, spermidine, spermine and 1-3 diaminopropane was found to be dependent of the activity of cell enzymes which could play a role to control cell proliferation by producing toxic metabolites.

Recent Advances in Type-2-Cell-Mediated Immunity: Insights from Helminth Infection.

PubMed

Harris, Nicola L; Loke, P'ng

2017-12-19

Type-2-cell-mediated immune responses play a critical role in mediating both host-resistance and disease-tolerance mechanisms during helminth infections. Recently, type 2 cell responses have emerged as major regulators of tissue repair and metabolic homeostasis even under steady-state conditions. In this review, we consider how studies of helminth infection have contributed toward our expanding cellular and molecular understanding of type-2-cell-mediated immunity, as well as new areas such as the microbiome. By studying how these successful parasites form chronic infections without overt pathology, we are gaining additional insights into allergic and inflammatory diseases, as well as normal physiology. Copyright © 2017 Elsevier Inc. All rights reserved.

Immune and Inflammatory Cell Composition of Human Lung Cancer Stroma

PubMed Central

Banat, G-Andre; Tretyn, Aleksandra; Pullamsetti, Soni Savai; Wilhelm, Jochen; Weigert, Andreas; Olesch, Catherine; Ebel, Katharina; Stiewe, Thorsten; Grimminger, Friedrich; Seeger, Werner; Fink, Ludger; Savai, Rajkumar

2015-01-01

Recent studies indicate that the abnormal microenvironment of tumors may play a critical role in carcinogenesis, including lung cancer. We comprehensively assessed the number of stromal cells, especially immune/inflammatory cells, in lung cancer and evaluated their infiltration in cancers of different stages, types and metastatic characteristics potential. Immunohistochemical analysis of lung cancer tissue arrays containing normal and lung cancer sections was performed. This analysis was combined with cyto-/histomorphological assessment and quantification of cells to classify/subclassify tumors accurately and to perform a high throughput analysis of stromal cell composition in different types of lung cancer. In human lung cancer sections we observed a significant elevation/infiltration of total-T lymphocytes (CD3+), cytotoxic-T cells (CD8+), T-helper cells (CD4+), B cells (CD20+), macrophages (CD68+), mast cells (CD117+), mononuclear cells (CD11c+), plasma cells, activated-T cells (MUM1+), B cells, myeloid cells (PD1+) and neutrophilic granulocytes (myeloperoxidase+) compared with healthy donor specimens. We observed all of these immune cell markers in different types of lung cancers including squamous cell carcinoma, adenocarcinoma, adenosquamous cell carcinoma, small cell carcinoma, papillary adenocarcinoma, metastatic adenocarcinoma, and bronchioloalveolar carcinoma. The numbers of all tumor-associated immune cells (except MUM1+ cells) in stage III cancer specimens was significantly greater than those in stage I samples. We observed substantial stage-dependent immune cell infiltration in human lung tumors suggesting that the tumor microenvironment plays a critical role during lung carcinogenesis. Strategies for therapeutic interference with lung cancer microenvironment should consider the complexity of its immune cell composition. PMID:26413839

ELEVATED HSP70 STIMULATES CELL PROLIFERATION AND IS CYTOPROTECTIVE AGAINST HEAT AND VINCRISTINE TOXICITY IN MCF-7 CELLS.

EPA Science Inventory

Heat-shock proteins (HSPs) play important roles in regulating cell growth and protecting cells from adverse effects of heat and chemical stress. In many types of cancer, elevated HSP70 levels are associated with poor prognosis and resistance to chemotherapeutic agents. In the pre...

Morphological study of tooth development in podoplanin-deficient mice.

PubMed

Takara, Kenyo; Maruo, Naoki; Oka, Kyoko; Kaji, Chiaki; Hatakeyama, Yuji; Sawa, Naruhiko; Kato, Yukinari; Yamashita, Junro; Kojima, Hiroshi; Sawa, Yoshihiko

2017-01-01

Podoplanin is a mucin-type highly O-glycosylated glycoprotein identified in several somatyic cells: podocytes, alveolar epithelial cells, lymphatic endothelial cells, lymph node stromal fibroblastic reticular cells, osteocytes, odontoblasts, mesothelial cells, glia cells, and others. It has been reported that podoplanin-RhoA interaction induces cytoskeleton relaxation and cell process stretching in fibroblastic cells and osteocytes, and that podoplanin plays a critical role in type I alveolar cell differentiation. It appears that podoplanin plays a number of different roles in contributing to cell functioning and growth by signaling. However, little is known about the functions of podoplanin in the somatic cells of the adult organism because an absence of podoplanin is lethal at birth by the respiratory failure. In this report, we investigated the tooth germ development in podoplanin-knockout mice, and the dentin formation in podoplanin-conditional knockout mice having neural crest-derived cells with deficiency in podoplanin by the Wnt1 promoter and enhancer-driven Cre recombinase: Wnt1-Cre;PdpnΔ/Δmice. In the Wnt1-Cre;PdpnΔ/Δmice, the tooth and alveolar bone showed no morphological abnormalities and grow normally, indicating that podoplanin is not critical in the development of the tooth and bone.

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.

Mast cell activators as novel immune regulators.

PubMed

Johnson-Weaver, Brandi; Choi, Hae Woong; Abraham, Soman N; Staats, Herman F

2018-05-26

Mast cells are an important cell type of the innate immune system that when activated, play a crucial role in generating protective innate host responses after bacterial and viral infection. Additionally, activated mast cells influence lymph node composition to regulate the induction of adaptive immune responses. The recognition that mast cells play a beneficial role in host responses to microbial infection and induction of adaptive immunity has provided the rationale to evaluate mast cell activators for use as antimicrobials or vaccine adjuvants. This review summarizes the role of mast cell activators in antimicrobial responses while also discussing the use of different classes of mast cell activators as potent vaccine adjuvants that enhance the induction of protective immune responses. Copyright © 2018 Elsevier Ltd. All rights reserved.

β-cell-specific CD8 T cell phenotype in type 1 diabetes reflects chronic autoantigen exposure

PubMed Central

McLaren, James E.; Dolton, Garry; Matthews, Katherine K.; Gostick, Emma; Kronenberg-Versteeg, Deborah; Eichmann, Martin; Knight, Robin R.; Heck, Susanne; Powrie, Jake; Bingley, Polly J.; Dayan, Colin M.; Miles, John J.; Sewell, Andrew K.

2015-01-01

Autoreactive CD8 T cells play a central role in the destruction of pancreatic islet β-cells that leads to type 1 diabetes, yet the key features of this immune-mediated process remain poorly defined. In this study, we combined high definition polychromatic flow cytometry with ultrasensitive peptide-human leukocyte antigen class I (pHLAI) tetramer staining to quantify and characterize β-cell-specific CD8 T cell populations in patients with recent onset type 1 diabetes and healthy controls. Remarkably, we found that β-cell-specific CD8 T cell frequencies in peripheral blood were similar between subject groups. In contrast to healthy controls, however, patients with newly diagnosed type 1 diabetes displayed hallmarks of antigen-driven expansion uniquely within the β-cell-specific CD8 T cell compartment. Molecular analysis of selected β-cell-specific CD8 T cell populations further revealed highly skewed oligoclonal T cell receptor (TCR) repertoires comprising exclusively private clonotypes. Collectively, these data identify novel and distinctive features of disease-relevant CD8 T cells that inform the immunopathogenesis of type 1 diabetes. PMID:25249579

Alternatively activated macrophages in helminth infections

PubMed Central

Kreider, Timothy; Anthony, Robert M.; Urban, Joseph F.; Gause, William C.

2007-01-01

Summary Helminthic parasites can trigger highly polarized immune responses typically associated with increased numbers of CD4+ Th2 cells, eosinophils, mast cells, and basophils. These cell populations are thought to coordinate an effective response ultimately leading to parasite expulsion, but they also play a role in the regulation of associated pathologic inflammation. Recent studies suggest that macrophages, conventionally associated with IFNγ-dominant Th1-type responses to many bacteria and viruses, also play an essential role in the Th2-type inflammatory response. These macrophages are referred to as alternatively activated macrophages (AAMΦs) as they express a characteristic pattern of cell surface and secreted molecules distinct from that of classically activated macrophages (CAMΦs) associated with microbe infections. In this review, we will discuss recent findings regarding the role of AAMΦs in the development of disease and host protection following helminth infection. PMID:17702561

Variability in Immunohistochemical Detection of Programmed Death Ligand 1 (PD-L1) in Cancer Tissue Types

PubMed Central

Scognamiglio, Giosuè; De Chiara, Anna; Di Bonito, Maurizio; Tatangelo, Fabiana; Losito, Nunzia Simona; Anniciello, Annamaria; De Cecio, Rossella; D’Alterio, Crescenzo; Scala, Stefania; Cantile, Monica; Botti, Gerardo

2016-01-01

In normal cell physiology, programmed death 1 (PD-1) and its ligand, PD-L1, play an immunoregulatory role in T-cell activation, tolerance, and immune-mediated tissue damage. The PD-1/PD-L1 pathway also plays a critical role in immune escape of tumor cells and has been demonstrated to correlate with a poor prognosis of patients with several types of cancer. However, recent reports have revealed that the immunohistochemical (IHC) expression of the PD-L1 in tumor cells is not uniform for the use of different antibodies clones, with variable specificity, often doubtful topographical localization, and with a score not uniquely defined. The purpose of this study was to analyze the IHC expression of PD-L1 on a large series of several human tumors to correctly define its staining in different tumor tissues. PMID:27213372

Regulation of cell-fate determination in Dictyostelium.

PubMed

Brown, J M; Firtel, R A

1999-12-15

A key step in the development of all multicellular organisms is the differentiation of specialized cell types. The eukaryotic microorganism Dictyostelium discoideum provides a unique experimental system for studying cell-type determination and spatial patterning in a developing multicellular organism. Unlike metazoans, which become multicellular by undergoing many rounds of cell division after fertilization of an egg, the social amoeba Dictyostelium achieves multicellularity by the aggregation of approximately 10(5) cells in response to nutrient depletion. Following aggregation, cell-type differentiation and morphogenesis result in a multicellular organism with only a few cell types that exhibit a defined patterning along the anterior-posterior axis of the organism. Analysis of the mechanisms that control these processes is facilitated by the relative simplicity of Dictyostelium development and the availability of molecular, genetic, and cell biological tools. Interestingly, analysis has shown that many molecules that play integral roles in the development of higher eukaryotes, such as PKA, STATs, and GSK-3, are also essential for cell-type differentiation and patterning in Dictyostelium. The role of these and other signaling pathways in the induction, maintenance, and patterning of cell types during Dictyostelium development is discussed.

Growth factor-induced morphological, physiological and molecular characteristics in cerebral endothelial cells.

PubMed

Krizbai, I A; Bauer, H; Amberger, A; Hennig, B; Szabó, H; Fuchs, R; Bauer, H C

2000-09-01

The capacity of vascular endothelial cells to modulate their phenotype in response to changes in environmental conditions is one of the most important characteristics of this cell type. Since different growth factors may play an important signalling role in this adaptive process we have investigated the effect of endothelial cell growth factor (ECGF) on morphological, physiological and molecular characteristics of cerebral endothelial cells (CECs). CECs grown in the presence of ECGF and its cofactor heparin exhibit an epithelial-like morphology (type I CECs). Upon removal of growth factors, CECs develop an elongated spindle-like shape (type II CECs) which is accompanied by the reorganization of actin filaments and the induction of alpha-actin expression. Since one of the most important functions of CECs is the creation of a selective diffusion barrier between the blood and the central nervous system (CNS), we have studied the expression of junction-related proteins in both cell types. We have found that removal of growth factors from endothelial cultures leads to the downregulation of cadherin and occludin protein levels. The loss of junctional proteins was accompanied by a significant increase in the migratory activity and an altered protease activity profile of the cells. TGF-beta1 suppressed endothelial migration in all experiments. Our data provide evidence to suggest that particular endothelial functions are largely controlled by the presence of growth factors. The differences in adhesiveness and migration may play a role in important physiological and pathological processes of endothelial cells such as vasculogenesis or tumor progression.

The role of the immune system in neurofibromatosis type 1-associated nervous system tumors.

PubMed

Karmakar, Souvik; Reilly, Karlyne M

2017-01-01

With the recent development of new anticancer therapies targeting the immune system, it is important to understand which immune cell types and cytokines play critical roles in suppressing or promoting tumorigenesis. The role of mast cells in promoting neurofibroma growth in neurofibromatosis type 1 (NF1) patients was hypothesized decades ago. More recent experiments in mouse models have demonstrated the causal role of mast cells in neurofibroma development and of microglia in optic pathway glioma development. We review here what is known about the role of NF1 mutation in immune cell function and the role of immune cells in promoting tumorigenesis in NF1. We also review the therapies targeting immune cell pathways and their promise in NF1 tumors.

K+ channels of Müller glial cells in retinal disorders.

PubMed

Gao, Feng; Xu, Linjie; Zhao, Yuan; Sun, Xinghuai; Wang, Zhongfeng

2018-02-01

Müller cell is the major type glial cell in the vertebrate retina. Müller cells express various types of K+ channels, such as inwardly rectifying K+ (Kir) channels, big conductance Ca2+-activated K+ (BKCa) channels, delayed rectifier K+ channels (KDR), and transient A-type K+ channels. These K+ channels play important roles in maintaining physiological functions of Müller cells. Under some retinal pathological conditions, the changed expression and functions of K+ channels may contribute to retinal pathogenesis. In this article, we reviewed the physiological properties of K+ channels in retinal Müller cells and the functional changes of these channels in retinal disorders. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Cell-type-specific expression of NFIX in the developing and adult cerebellum.

PubMed

Fraser, James; Essebier, Alexandra; Gronostajski, Richard M; Boden, Mikael; Wainwright, Brandon J; Harvey, Tracey J; Piper, Michael

2017-07-01

Transcription factors from the nuclear factor one (NFI) family have been shown to play a central role in regulating neural progenitor cell differentiation within the embryonic and post-natal brain. NFIA and NFIB, for instance, promote the differentiation and functional maturation of granule neurons within the cerebellum. Mice lacking Nfix exhibit delays in the development of neuronal and glial lineages within the cerebellum, but the cell-type-specific expression of this transcription factor remains undefined. Here, we examined the expression of NFIX, together with various cell-type-specific markers, within the developing and adult cerebellum using both chromogenic immunohistochemistry and co-immunofluorescence labelling and confocal microscopy. In embryos, NFIX was expressed by progenitor cells within the rhombic lip and ventricular zone. After birth, progenitor cells within the external granule layer, as well as migrating and mature granule neurons, expressed NFIX. Within the adult cerebellum, NFIX displayed a broad expression profile, and was evident within granule cells, Bergmann glia, and interneurons, but not within Purkinje neurons. Furthermore, transcriptomic profiling of cerebellar granule neuron progenitor cells showed that multiple splice variants of Nfix are expressed within this germinal zone of the post-natal brain. Collectively, these data suggest that NFIX plays a role in regulating progenitor cell biology within the embryonic and post-natal cerebellum, as well as an ongoing role within multiple neuronal and glial populations within the adult cerebellum.

Cadherin-23 Mediates Heterotypic Cell-Cell Adhesion between Breast Cancer Epithelial Cells and Fibroblasts

PubMed Central

Apostolopoulou, Maria; Ligon, Lee

2012-01-01

In the early stages of breast cancer metastasis, epithelial cells penetrate the basement membrane and invade the surrounding stroma, where they encounter fibroblasts. Paracrine signaling between fibroblasts and epithelial tumor cells contributes to the metastatic cascade, but little is known about the role of adhesive contacts between these two cell types in metastasis. Here we show that MCF-7 breast cancer epithelial cells and normal breast fibroblasts form heterotypic adhesions when grown together in co-culture, as evidenced by adhesion assays. PCR and immunoblotting show that both cell types express multiple members of the cadherin superfamily, including the atypical cadherin, cadherin-23, when grown in isolation and in co-culture. Immunocytochemistry experiments show that cadherin-23 localizes to homotypic adhesions between MCF-7 cells and also to heterotypic adhesions between the epithelial cells and fibroblasts, and antibody inhibition and RNAi experiments show that cadherin-23 plays a role in mediating these adhesive interactions. Finally, we show that cadherin-23 is upregulated in breast cancer tissue samples, and we hypothesize that heterotypic adhesions mediated by this atypical cadherin may play a role in the early stages of metastasis. PMID:22413011

Resistance of hypoxic cells to ionizing radiation is influenced by homologous recombination status

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

Sprong, Debbie; Janssen, Hilde L.; Vens, Conchita

2006-02-01

Purpose: To determine the role of DNA repair in hypoxic radioresistance. Methods and Materials: Chinese hamster cell lines with mutations in homologous recombination (XRCC2, XRCC3, BRAC2, RAD51C) or nonhomologous end-joining (DNA-PKcs) genes were irradiated under normoxic (20% oxygen) and hypoxic (<0.1% oxygen) conditions, and the oxygen enhancement ratio (OER) was calculated. In addition, Fanconi anemia fibroblasts (complementation groups C and G) were compared with fibroblasts from nonsyndrome patients. RAD51 foci were studied using immunofluorescence. Results: All hamster cell lines deficient in homologous recombination showed a decrease in OER (1.5-2.0 vs. 2.6-3.0 for wild-types). In contrast, the OER for the DNA-PKcs-deficientmore » line was comparable to wild-type controls. The two Fanconi anemia cell strains also showed a significant reduction in OER. The OER for RAD51 foci formation at late times after irradiation was considerably lower than that for survival in wild-type cells. Conclusion: Homologous recombination plays an important role in determining hypoxic cell radiosensitivity. Lower OERs have also been reported in cells deficient in XPF and ERCC1, which, similar to homologous recombination genes, are known to play a role in cross-link repair. Because Fanconi anemia cells are also sensitive to cross-linking agents, this strengthens the notion that the capacity to repair cross-links determines hypoxic radiosensitivity.« less

Biology of the cell cycle inhibitor p21(CDKN1A): molecular mechanisms and relevance in chemical toxicology.

PubMed

Dutto, Ilaria; Tillhon, Micol; Cazzalini, Ornella; Stivala, Lucia A; Prosperi, Ennio

2015-02-01

The cell cycle inhibitor p21(CDKN1A) is a protein playing multiple roles not only in the DNA damage response, but also in many cellular processes during unperturbed cell growth. The main, well-known function of p21 is to arrest cell cycle progression by inhibiting the activity of cyclin-dependent kinases. In addition, p21 is involved in the regulation of transcription, apoptosis, DNA repair, as well as cell motility. However, p21 appears to a have a dual-face behavior because, in addition to its tumor suppressor functions, it may act as an oncogene, depending on the cell type and on the cellular localization. As a biomarker of the cell response to different toxic stimuli, p21 expression and functions have been analyzed in an impressive number of studies investigating the activity of several types of chemicals, in order to determine their possible harmful effects on human cells. Here, we review these studies in order to highlight the different roles p21 may play in the cell response to chemical exposure and to better evaluate the information provided by this biomarker.

Endothelial binding of beta toxin to small intestinal mucosal endothelial cells in early stages of experimentally induced Clostridium perfringens type C enteritis in pigs.

PubMed

Schumacher, V L; Martel, A; Pasmans, F; Van Immerseel, F; Posthaus, H

2013-07-01

Beta toxin (CPB) is known to be an essential virulence factor in the development of lesions of Clostridium perfringens type C enteritis in different animal species. Its target cells and exact mechanism of toxicity have not yet been clearly defined. Here, we evaluate the suitability of a neonatal piglet jejunal loop model to investigate early lesions of C. perfringens type C enteritis. Immunohistochemically, CPB was detected at microvascular endothelial cells in intestinal villi during early and advanced stages of lesions induced by C. perfringens type C. This was first associated with capillary dilatation and subsequently with widespread hemorrhage in affected intestinal segments. CPB was, however, not demonstrated on intestinal epithelial cells. This indicates a tropism of CPB toward endothelial cells and suggests that CPB-induced endothelial damage plays an important role in the early stages of C. perfringens type C enteritis in pigs.

IG20/MADD Plays a Critical Role in Glucose-Induced Insulin Secretion

PubMed Central

Li, Liang-cheng; Wang, Yong; Carr, Ryan; Haddad, Christine Samir; Li, Ze; Qian, Lixia; Oberholzer, Jose; Maker, Ajay V.; Wang, Qian; Prabhakar, Bellur S.

2014-01-01

Pancreatic β-cell dysfunction is a common feature of type 2 diabetes. Earlier, we had cloned IG20 cDNA from a human insulinoma and had shown that IG20/MADD can encode six different splice isoforms that are differentially expressed and have unique functions, but its role in β-cell function was unexplored. To investigate the role of IG20/MADD in β-cell function, we generated conditional knockout (KMA1ko) mice. Deletion of IG20/MADD in β-cells resulted in hyperglycemia and glucose intolerance associated with reduced and delayed glucose-induced insulin production. KMA1ko β-cells were able to process insulin normally but had increased insulin accumulation and showed a severe defect in glucose-induced insulin release. These findings indicated that IG20/MADD plays a critical role in glucose-induced insulin release from β-cells and that its functional disruption can cause type 2 diabetes. The clinical relevance of these findings is highlighted by recent reports of very strong association of the rs7944584 single nucleotide polymorphism (SNP) of IG20/MADD with fasting hyperglycemia/diabetes. Thus, IG20/MADD could be a therapeutic target for type 2 diabetes, particularly in those with the rs7944584 SNP. PMID:24379354

The role of rare innate immune cells in Type 2 immune activation against parasitic helminths.

PubMed

Webb, Lauren M; Tait Wojno, Elia D

2017-09-01

The complexity of helminth macroparasites is reflected in the intricate network of host cell types that participate in the Type 2 immune response needed to battle these organisms. In this context, adaptive T helper 2 cells and the Type 2 cytokines interleukin (IL)-4, IL-5, IL-9 and IL-13 have been the focus of research for years, but recent work has demonstrated that the innate immune system plays an essential role. Some innate immune cells that promote Type 2 immunity are relatively abundant, such as macrophages and eosinophils. However, we now appreciate that more rare cell types including group 2 innate lymphoid cells, basophils, mast cells and dendritic cells make significant contributions to these responses. These cells are found at low frequency but they are specialized to their roles - located at sites such as the skin, lung and gut, where the host combats helminth parasites. These cells respond rapidly and robustly to worm antigens and worm-induced damage to produce essential cytokines, chemokines, eicosanoids and histamine to activate damaged epithelium and to recruit other effectors. Thus, a greater understanding of how these cells operate is essential to understand how the host protects itself during helminth infection.

Type 1 Diabetes and NKT Cells: A Report on the 3rd International Workshop on NKT Cells and CD1-Mediated Antigen Presentation, September 2004, Heron Island, QLD, Australia

PubMed Central

Fletcher, Julie M.; Jordan, Margaret A.; Baxter, Alan G.

2004-01-01

NKT cells play a major role in regulating the vigor and character of a broad range of immune responses. Defects in NKT cell numbers and function have been associated with type 1 diabetes, especially in the NOD mouse model. The 3rd International Workshop on NKT Cells and CD1-Mediated Antigen Presentation provided an opportunity for researchers in the field of NKT cell biology to discuss their latest results, many of which have direct relevance to understanding the etiology and pathogenesis of diabetes. PMID:17491677

CXCR4 in breast cancer: oncogenic role and therapeutic targeting

PubMed Central

Xu, Chao; Zhao, Hong; Chen, Haitao; Yao, Qinghua

2015-01-01

Chemokines are 8–12 kDa peptides that function as chemoattractant cytokines and are involved in cell activation, differentiation, and trafficking. Chemokines bind to specific G-protein-coupled seven-span transmembrane receptors. Chemokines play a fundamental role in the regulation of a variety of cellular, physiological, and developmental processes. Their aberrant expression can lead to a variety of human diseases including cancer. C-X-C chemokine receptor type 4 (CXCR4), also known as fusin or CD184, is an alpha-chemokine receptor specific for stromal-derived-factor-1 (SDF-1 also called CXCL12). CXCR4 belongs to the superfamily of the seven transmembrane domain heterotrimeric G protein-coupled receptors and is functionally expressed on the cell surface of various types of cancer cells. CXCR4 also plays a role in the cell proliferation and migration of these cells. Recently, CXCR4 has been reported to play an important role in cell survival, proliferation, migration, as well as metastasis of several cancers including breast cancer. This review is mainly focused on the current knowledge of the oncogenic role and potential drugs that target CXCR4 in breast cancer. Additionally, CXCR4 proangiogenic molecular mechanisms will be reviewed. Strict biunivocal binding affinity and activation of CXCR4/CXCL12 complex make CXCR4 a unique molecular target for prevention and treatment of breast cancer. PMID:26356032

Development and characterization of mouse monoclonal antibody reactive with chicken IL-8

USDA-ARS?s Scientific Manuscript database

Interleukin-8/CXCL8 (IL-8) is a CXC-family chemokine produced by fibroblasts and other cell types including epithelial cells, endothelial cells, neutrophils and macrophages. Since IL-8 has functions to attract lymphocytes to sites of tissue damage, it plays a role in inflammatory responses and wound...

Development and characterization of monoclonal antibodies specific for chicken IL-8

USDA-ARS?s Scientific Manuscript database

Interleukin-8/CXCL8 (IL-8) is a CXC-family chemokine produced by fibroblasts and other cell types, including epithelial cells, endothelial cells, neutrophils, and macrophages. Given that IL-8 attracts lymphocytes to the sites of tissue damage, IL-8 plays a role in the inflammatory response and woun...

Type two innate lymphoid cells; the Janus cells in health and disease

PubMed Central

Maazi, Hadi; Akbari, Omid

2017-01-01

Summary Innate lymphoid cells are functionally diverse subsets of immune cells including the conventional natural killer cells, lymphoid tissue inducers, type 1, 2 and 3 with significant roles in immunity and pathogenesis of inflammatory diseases. Type 2 innate lymphoid cells (ILC2s) resemble type 2 helper (Th2) cells in cytokine production and contribute to anti-helminth immunity, maintaining mucosal tissue integrity and adipose tissue browning. ILC2s play important roles in the pathogenesis of allergic diseases and asthma. Studying the pathways of activation and regulation of ILC2s are currently a priority for giving a better understanding of pathogenesis of diseases with immunological roots. Recently, our laboratory and others have shown several pathways of regulation of ILC2s by costimulatory molecules such as ICOS, regulatory T cells and by compounds such as nicotine. In this review, we summarize the current understanding of the mechanisms of activation and regulation of ILC2s and the role of these cells in health and disease. PMID:28658553

Regulation of vacuolar H{sup +}-ATPase in microglia by RANKL

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

Serrano, Eric M.; Ricofort, Ryan D.; Zuo, Jian

2009-11-06

Vacuolar H{sup +}-ATPases (V-ATPases) are large electrogenic proton pumps composed of numerous subunits that play vital housekeeping roles in the acidification of compartments of the endocytic pathway. Additionally, V-ATPases play specialized roles in certain cell types, a capacity that is linked to cell type selective expression of isoforms of some of the subunits. We detected low levels of the a3 isoform of the a-subunit in mouse brain extracts. Examination of various brain-derived cell types by immunoblotting showed a3 was expressed in the N9 microglia cell line and in primary microglia, but not in other cell types. The expression of a3more » in osteoclasts requires stimulation by Receptor Activator of Nuclear Factor {kappa}B-ligand (RANKL). We found that Receptor Activator of Nuclear Factor {kappa}B (RANK) was expressed by microglia. Stimulation of microglia with RANKL triggered increased expression of a3. V-ATPases in microglia were shown to bind microfilaments, and stimulation with RANKL increased the proportion of V-ATPase associated with the detergent-insoluble cytoskeletal fraction and with actin. In summary, microglia express the a3-subunit of V-ATPase. The expression of a3 and the interaction between V-ATPases and microfilaments was modulated by RANKL. These data suggest a novel molecular pathway for regulating microglia.« less

Ascorbic acid induces alkaline phosphatase, type X collagen, and calcium deposition in cultured chick chondrocytes.

PubMed

Leboy, P S; Vaias, L; Uschmann, B; Golub, E; Adams, S L; Pacifici, M

1989-10-15

During the process of endochondral bone formation, proliferating chondrocytes give rise to hypertrophic chondrocytes, which then deposit a mineralized matrix to form calcified cartilage. Chondrocyte hypertrophy and matrix mineralization are associated with expression of type X collagen and the induction of high levels of the bone/liver/kidney isozyme of alkaline phosphatase. To determine what role vitamin C plays in these processes, chondrocytes derived from the cephalic portion of 14-day chick embryo sternae were grown in the absence or presence of exogenous ascorbic acid. Control untreated cells displayed low levels of type X collagen and alkaline phosphatase activity throughout the culture period. However, cells grown in the presence of ascorbic acid produced increasing levels of alkaline phosphatase activity and type X collagen mRNA and protein. Both alkaline phosphatase activity and type X collagen mRNA levels began to increase within 24 h of ascorbate treatment; by 9 days, the levels of both alkaline phosphatase activity and type X collagen mRNA were 15-20-fold higher than in non-ascorbate-treated cells. Ascorbate treatment also increased calcium deposition in the cell layer and decreased the levels of types II and IX collagen mRNAs; these effects lagged significantly behind the elevation of alkaline phosphatase and type X collagen. Addition of beta-glycerophosphate to the medium increased calcium deposition in the presence of ascorbate but had no effect on levels of collagen mRNAs or alkaline phosphatase. The results suggest that vitamin C may play an important role in endochondral bone formation by modulating gene expression in hypertrophic chondrocytes.

Cell uptake survey of pegylated nanographene oxide.

PubMed

Vila, M; Portolés, M T; Marques, P A A P; Feito, M J; Matesanz, M C; Ramírez-Santillán, C; Gonçalves, G; Cruz, S M A; Nieto, A; Vallet-Regi, M

2012-11-23

Graphene and more specifically, nanographene oxide (GO) has been proposed as a highly efficient antitumoral therapy agent. Nevertheless, its cell uptake kinetics, its influence in different types of cells and the possibility of controlling cellular internalization timing, is still a field that remains unexplored. Herein, different cell types have been cultured in vitro for several incubation periods in the presence of 0.075 mg ml(-1) pegylated GO solutions. GO uptake kinetics revealed differences in the agent's uptake amount and speed as a function of the type of cell involved. Osteoblast-like cells GO uptake is higher and faster without resulting in greater cell membrane damage. Moreover, the dependence on the commonly used PEG nature (number of branches) also influences the viability and cell uptake speed. These facts play an important role in the future definition of timing parameters and selective cell uptake control in order to achieve an effective therapy.

Stem cells in the Drosophila digestive system.

PubMed

Zeng, Xiankun; Chauhan, Chhavi; Hou, Steven X

2013-01-01

Adult stem cells maintain tissue homeostasis by continuously replenishing damaged, aged and dead cells in any organism. Five types of region and organ-specific multipotent adult stem cells have been identified in the Drosophila digestive system: intestinal stem cells (ISCs) in the posterior midgut; hindgut intestinal stem cells (HISCs) at the midgut/hindgut junction; renal and nephric stem cells (RNSCs) in the Malpighian Tubules; type I gastric stem cells (GaSCs) at foregut/midgut junction; and type II gastric stem cells (GSSCs) at the middle of the midgut. Despite the fact that each type of stem cell is unique to a particular organ, they share common molecular markers and some regulatory signaling pathways. Due to the simpler tissue structure, ease of performing genetic analysis, and availability of abundant mutants, Drosophila serves as an elegant and powerful model system to study complex stem cell biology. The recent discoveries, particularly in the Drosophila ISC system, have greatly advanced our understanding of stem cell self-renewal, differentiation, and the role of stem cells play in tissue homeostasis/regeneration and adaptive tissue growth.

Discovery of a “White-Gray-Opaque” Tristable Phenotypic Switching System in Candida albicans: Roles of Non-genetic Diversity in Host Adaptation

PubMed Central

Guan, Guobo; Dai, Yu; Nobile, Clarissa J.; Liang, Weihong; Cao, Chengjun; Zhang, Qiuyu; Zhong, Jin; Huang, Guanghua

2014-01-01

Non-genetic phenotypic variations play a critical role in the adaption to environmental changes in microbial organisms. Candida albicans, a major human fungal pathogen, can switch between several morphological phenotypes. This ability is critical for its commensal lifestyle and for its ability to cause infections. Here, we report the discovery of a novel morphological form in C. albicans, referred to as the “gray” phenotype, which forms a tristable phenotypic switching system with the previously reported white and opaque phenotypes. White, gray, and opaque cell types differ in a number of aspects including cellular and colony appearances, mating competency, secreted aspartyl proteinase (Sap) activities, and virulence. Of the three cell types, gray cells exhibit the highest Sap activity and the highest ability to cause cutaneous infections. The three phenotypes form a tristable phenotypic switching system, which is independent of the regulation of the mating type locus (MTL). Gray cells mate over 1,000 times more efficiently than do white cells, but less efficiently than do opaque cells. We further demonstrate that the master regulator of white-opaque switching, Wor1, is essential for opaque cell formation, but is not required for white-gray transitions. The Efg1 regulator is required for maintenance of the white phenotype, but is not required for gray-opaque transitions. Interestingly, the wor1/wor1 efg1/efg1 double mutant is locked in the gray phenotype, suggesting that Wor1 and Efg1 could function coordinately and play a central role in the regulation of gray cell formation. Global transcriptional analysis indicates that white, gray, and opaque cells exhibit distinct gene expression profiles, which partly explain their differences in causing infections, adaptation ability to diverse host niches, metabolic profiles, and stress responses. Therefore, the white-gray-opaque tristable phenotypic switching system in C. albicans may play a significant role in a wide range of biological aspects in this common commensal and pathogenic fungus. PMID:24691005

Discovery of a "white-gray-opaque" tristable phenotypic switching system in candida albicans: roles of non-genetic diversity in host adaptation.

PubMed

Tao, Li; Du, Han; Guan, Guobo; Dai, Yu; Nobile, Clarissa J; Liang, Weihong; Cao, Chengjun; Zhang, Qiuyu; Zhong, Jin; Huang, Guanghua

2014-04-01

Non-genetic phenotypic variations play a critical role in the adaption to environmental changes in microbial organisms. Candida albicans, a major human fungal pathogen, can switch between several morphological phenotypes. This ability is critical for its commensal lifestyle and for its ability to cause infections. Here, we report the discovery of a novel morphological form in C. albicans, referred to as the "gray" phenotype, which forms a tristable phenotypic switching system with the previously reported white and opaque phenotypes. White, gray, and opaque cell types differ in a number of aspects including cellular and colony appearances, mating competency, secreted aspartyl proteinase (Sap) activities, and virulence. Of the three cell types, gray cells exhibit the highest Sap activity and the highest ability to cause cutaneous infections. The three phenotypes form a tristable phenotypic switching system, which is independent of the regulation of the mating type locus (MTL). Gray cells mate over 1,000 times more efficiently than do white cells, but less efficiently than do opaque cells. We further demonstrate that the master regulator of white-opaque switching, Wor1, is essential for opaque cell formation, but is not required for white-gray transitions. The Efg1 regulator is required for maintenance of the white phenotype, but is not required for gray-opaque transitions. Interestingly, the wor1/wor1 efg1/efg1 double mutant is locked in the gray phenotype, suggesting that Wor1 and Efg1 could function coordinately and play a central role in the regulation of gray cell formation. Global transcriptional analysis indicates that white, gray, and opaque cells exhibit distinct gene expression profiles, which partly explain their differences in causing infections, adaptation ability to diverse host niches, metabolic profiles, and stress responses. Therefore, the white-gray-opaque tristable phenotypic switching system in C. albicans may play a significant role in a wide range of biological aspects in this common commensal and pathogenic fungus.

Increased metastatic potential of tumor cells in von Willebrand factor-deficient mice.

PubMed

Terraube, V; Pendu, R; Baruch, D; Gebbink, M F B G; Meyer, D; Lenting, P J; Denis, C V

2006-03-01

The key role played by von Willebrand factor (VWF) in platelet adhesion suggests a potential implication in various pathologies, where this process is involved. In cancer metastasis development, tumor cells interact with platelets and the vessel wall to extravasate from the circulation. As a potential mediator of platelet-tumor cell interactions, VWF could influence this early step of tumor spread and therefore play a role in cancer metastasis. To investigate whether VWF is involved in metastasis development. In a first step, we characterized the interaction between murine melanoma cells B16-BL6 and VWF in vitro. In a second step, an experimental metastasis model was used to compare the formation of pulmonary metastatic foci in C57BL/6 wild-type and VWF-null mice following the injection of B16-BL6 cells or Lewis lung carcinoma cells. In vitro adhesion assays revealed that VWF is able to promote a dose-dependent adhesion of B16-BL6 cells via its Arg-Gly-Asp (RGD) sequence. In the experimental metastasis model, we found a significant increase in the number of pulmonary metastatic foci in VWF-null mice compared with the wild-type mice, a phenotype that could be corrected by restoring VWF plasma levels. We also showed that increased survival of the tumor cells in the lungs during the first 24 h in the absence of VWF was the cause of this increased metastasis. These findings suggest that VWF plays a protective role against tumor cell dissemination in vivo. Underlying mechanisms remain to be investigated.

Controlling the burn and fueling the fire: defining the role for the alarmin interleukin-33 in alloimmunity.

PubMed

Liu, Quan; Turnquist, Heth R

2016-02-01

The purpose of this review is to provide a general update on recent developments in the immunobiology of IL-33 and IL-33-targeted immune cells. We also discuss emerging concepts regarding the potential role IL-33 appears to play in altering alloimmune responses mediating host-versus-graft and graft-versus-host alloresponses. Stromal cells and leukocytes display regulated expression of IL-33 and may actively or passively secrete this pleotropic cytokine. Type 2 innate lymphoid cells and a large proportion of tissue resident regulatory T cells (Treg) express membrane-bound suppressor of tumorigenicity 2 (ST2), the IL-33 receptor. Although Treg are appreciated suppressors of the inflammatory function of immune cells, both type 2 innate lymphoid cells and tissue resident Treg could play key roles in tissue repair and homeostasis. The functions of IL-33 in transplantation are poorly understood. However, like other disease models, the functions of IL-33 in alloimmunity appear to be quite pleiotropic. IL-33 is associated with immune regulation and graft protection in cardiac transplant settings. Yet, it is highly proinflammatory and stimulates lethal graft-versus-host disease through its capacity to stimulate type 1 immunity. Intensive studies on IL-33/ST2 signaling pathways and ST2 cell populations in solid organ and cell transplantation are warranted. A better understanding of this important pathway will provide promising therapeutic targets controlling pathogenic alloimmune responses, as well as potentially facilitating the function of regulatory and reparative immune cells posttransplantation.

The Functions of Type I and Type II Natural Killer T (NKT) Cells in Inflammatory Bowel Diseases

PubMed Central

Liao, Chia-Min; Zimmer, Michael I.; Wang, Chyung-Ru

2013-01-01

CD1d-restricted natural killer T (NKT) cells are a distinct subset of T cells that rapidly produce an array of cytokines upon activation and play a critical role in regulating various immune responses. NKT cells are classified into two groups based on differences in T cell receptor (TCR) usage. Type I NKT cells have an invariant TCRα-chain and are readily detectable by α-galactosylceramide (α-GalCer)-loaded CD1d tetramers. Type II NKT cells have a more diverse TCR repertoire and cannot be directly identified. Both types of NKT cells as well as multiple CD1d-expressing cell types are present in the intestine and their interactions are likely to be modulated by pathogenic and commensal microbes, which in turn contribute to the intestinal immune responses in health and disease. Indeed, in several animal models of inflammatory bowel disease (IBD), Type I NKT cells have been shown to make both protective and pathogenic contributions to disease. In contrast, in human patients suffering from ulcerative colitis (UC), and a mouse model in which both CD1d expression and the frequency of Type II NKT cells are increased, Type II NKT cells appear to promote intestinal inflammation. In this review, we summarize present knowledge on the antigen recognition, activation and function of NKT cells with a particular focus on their role in IBD, and discuss factors that may influence the functional outcome of NKT cell responses in intestinal inflammation. PMID:23518808

RGMb protects against acute kidney injury by inhibiting tubular cell necroptosis via an MLKL-dependent mechanism.

PubMed

Liu, Wenjing; Chen, Binbin; Wang, Yang; Meng, Chenling; Huang, Huihui; Huang, Xiao-Ru; Qin, Jinzhong; Mulay, Shrikant R; Anders, Hans-Joachim; Qiu, Andong; Yang, Baoxue; Freeman, Gordon J; Lu, Hua Jenny; Lin, Herbert Y; Zheng, Zhi-Hua; Lan, Hui-Yao; Huang, Yu; Xia, Yin

2018-02-13

Tubular cell necrosis is a key histological feature of acute kidney injury (AKI). Necroptosis is a type of programed necrosis, which is executed by mixed lineage kinase domain-like protein (MLKL) upon its binding to the plasma membrane. Emerging evidence indicates that necroptosis plays a critical role in the development of AKI. However, it is unclear whether renal tubular cells undergo necroptosis in vivo and how the necroptotic pathway is regulated during AKI. Repulsive guidance molecule (RGM)-b is a member of the RGM family. Our previous study demonstrated that RGMb is highly expressed in kidney tubular epithelial cells, but its biological role in the kidney has not been well characterized. In the present study, we found that RGMb reduced membrane-associated MLKL levels and inhibited necroptosis in cultured cells. During ischemia/reperfusion injury (IRI) or oxalate nephropathy, MLKL was induced to express on the apical membrane of proximal tubular (PT) cells. Specific knockout of Rgmb in tubular cells (Rgmb cKO) increased MLKL expression at the apical membrane of PT cells and induced more tubular cell death and more severe renal dysfunction compared with wild-type mice. Treatment with the necroptosis inhibitor Necrostatin-1 or GSK'963 reduced MLKL expression on the apical membrane of PT cells and ameliorated renal function impairment after IRI in both wild-type and Rgmb cKO mice. Taken together, our results suggest that proximal tubular cell necroptosis plays an important role in AKI, and that RGMb protects against AKI by inhibiting MLKL membrane association and necroptosis in proximal tubular cells.

The essential role of G protein-coupled receptor (GPCR) signaling in regulating T cell immunity.

PubMed

Wang, Dashan

2018-06-01

The aim of this paper is to clarify the critical role of GPCR signaling in T cell immunity. The G protein-coupled receptors (GPCRs) are the most common targets in current pharmaceutical industry, and represent the largest and most versatile family of cell surface communicating molecules. GPCRs can be activated by a diverse array of ligands including neurotransmitters, chemokines as well as sensory stimuli. Therefore, GPCRs are involved in many key cellular and physiological processes, such as sense of light, taste and smell, neurotransmission, metabolism, endocrine and exocrine secretion. In recent years, GPCRs have been found to play an important role in immune system. T cell is an important type of immune cell, which plays a central role in cell-mediated immunity. A variety of GPCRs and their signaling mediators (RGS proteins, GRKs and β-arrestin) have been found to express in T cells and involved T cell-mediated immunity. We will summarize the role of GPCR signaling and their regulatory molecules in T cell activation, homeostasis and function in this article. GPCR signaling plays an important role in T cell activation, homeostasis and function. GPCR signaling is critical in regulating T cell immunity.

Novel histone deacetylase inhibitor CG200745 induces clonogenic cell death by modulating acetylation of p53 in cancer cells.

PubMed

Oh, Eun-Taex; Park, Moon-Taek; Choi, Bo-Hwa; Ro, Seonggu; Choi, Eun-Kyung; Jeong, Seong-Yun; Park, Heon Joo

2012-04-01

Histone deacetylase (HDAC) plays an important role in cancer onset and progression. Therefore, inhibition of HDAC offers potential as an effective cancer treatment regimen. CG200745, (E)-N(1)-(3-(dimethylamino)propyl)-N(8)-hydroxy-2-((naphthalene-1-loxy)methyl)oct-2-enediamide, is a novel HDAC inhibitor presently undergoing a phase I clinical trial. Enhancement of p53 acetylation by HDAC inhibitors induces cell cycle arrest, differentiation, and apoptosis in cancer cells. The purpose of the present study was to investigate the role of p53 acetylation in the cancer cell death caused by CG200745. CG200745-induced clonogenic cell death was 2-fold greater in RKO cells expressing wild-type p53 than in p53-deficient RC10.1 cells. CG200745 treatment was also cytotoxic to PC-3 human prostate cancer cells, which express wild-type p53. CG200745 increased acetylation of p53 lysine residues K320, K373, and K382. CG200745 induced the accumulation of p53, promoted p53-dependent transactivation, and enhanced the expression of MDM2 and p21(Waf1/Cip1) proteins, which are encoded by p53 target genes. An examination of CG200745 effects on p53 acetylation using cells transfected with various p53 mutants showed that cells expressing p53 K382R mutants were significantly resistant to CG200745-induced clonogenic cell death compared with wild-type p53 cells. Moreover, p53 transactivation in response to CG200745 was suppressed in all cells carrying mutant forms of p53, especially K382R. Taken together, these results suggest that acetylation of p53 at K382 plays an important role in CG200745-induced p53 transactivation and clonogenic cell death.

Traction force microscopy in rapidly moving cells reveals separate roles for ROCK and MLCK in the mechanics of retraction.

PubMed

Morin, Timothy R; Ghassem-Zadeh, Sean A; Lee, Juliet

2014-08-15

Retraction is a major rate-limiting step in cell motility, particularly in slow moving cell types that form large stable adhesions. Myosin II dependent contractile forces are thought to facilitate detachment by physically pulling up the rear edge. However, retraction can occur in the absence of myosin II activity in cell types that form small labile adhesions. To investigate the role of contractile force generation in retraction, we performed traction force microscopy during the movement of fish epithelial keratocytes. By correlating changes in local traction stress at the rear with the area retracted, we identified four distinct modes of retraction. "Recoil" retractions are preceded by a rise in local traction stress, while rear edge is temporarily stuck, followed by a sharp drop in traction stress upon detachment. This retraction type was most common in cells generating high average traction stress. In "pull" type retractions local traction stress and area retracted increase concomitantly. This was the predominant type of retraction in keratocytes and was observed mostly in cells generating low average traction stress. "Continuous" type retractions occur without any detectable change in traction stress, and are seen in cells generating low average traction stress. In contrast, to many other cell types, "release" type retractions occur in keratocytes following a decrease in local traction stress. Our identification of distinct modes of retraction suggests that contractile forces may play different roles in detachment that are related to rear adhesion strength. To determine how the regulation of contractility via MLCK or Rho kinase contributes to the mechanics of detachment, inhibitors were used to block or augment these pathways. Modulation of MLCK activity led to the most rapid change in local traction stress suggesting its importance in regulating attachment strength. Surprisingly, Rho kinase was not required for detachment, but was essential for localizing retraction to the rear. We suggest that in keratocytes MLCK and Rho kinase play distinct, complementary roles in the respective temporal and spatial control of rear detachment that is essential for maintaining rapid motility. Copyright © 2014 Elsevier Inc. All rights reserved.

NKT Cell Subsets Can Exert Opposing Effects in Autoimmunity, Tumor Surveillance and Inflammation

PubMed Central

Viale, Rachael; Ware, Randle; Maricic, Igor; Chaturvedi, Varun; Kumar, Vipin

2014-01-01

The innate-like natural killer T (NKT) cells are essential regulators of immunity. These cells comprise at least two distinct subsets and recognize different lipid antigens presented by the MHC class I like molecules CD1d. The CD1d-dependent recognition pathway of NKT cells is highly conserved from mouse to humans. While most type I NKT cells can recognize αGalCer and express a semi-invariant T cell receptor (TCR), a major population of type II NKT cells reactive to sulfatide utilizes an oligoclonal TCR. Furthermore TCR recognition features of NKT subsets are also distinctive with almost parallel as opposed to perpendicular footprints on the CD1d molecules for the type I and type II NKT cells respectively. Here we present a view based upon the recent studies in different clinical and experimental settings that while type I NKT cells are more often pathogenic, they may also be regulatory. On the other hand, sulfatide-reactive type II NKT cells mostly play an inhibitory role in the control of autoimmune and inflammatory diseases. Since the activity and cytokine secretion profiles of NKT cell subsets can be modulated differently by lipid ligands or their analogs, novel immunotherapeutic strategies are being developed for their differential activation for potential intervention in inflammatory diseases. PMID:25288922

Cell type-specific localization of Ephs pairing with ephrin-B2 in the rat postnatal pituitary gland.

PubMed

Yoshida, Saishu; Kato, Takako; Kanno, Naoko; Nishimura, Naoto; Nishihara, Hiroto; Horiguchi, Kotaro; Kato, Yukio

2017-10-01

Sox2-expressing stem/progenitor cells in the anterior lobe of the pituitary gland form two types of micro-environments (niches): the marginal cell layer and dense cell clusters in the parenchyma. In relation to the mechanism of regulation of niches, juxtacrine signaling via ephrin and its receptor Eph is known to play important roles in various niches. The ephrin and Eph families are divided into two subclasses to create ephrin/Eph signaling in co-operation with confined partners. Recently, we reported that ephrin-B2 localizes specifically to both pituitary niches. However, the Ephs interacting with ephrin-B2 in these pituitary niches have not yet been identified. Therefore, the present study aims to identify the Ephs interacting with ephrin-B2 and the cells that produce them in the rat pituitary gland. In situ hybridization and immunohistochemistry demonstrated cell type-specific localization of candidate interacting partners for ephrin-B2, including EphA4 in cells located in the posterior lobe, EphB1 in gonadotropes, EphB2 in corticotropes, EphB3 in stem/progenitor cells and EphB4 in endothelial cells in the adult pituitary gland. In particular, double-immunohistochemistry showed cis-interactions between EphB3 and ephrin-B2 in the apical cell membranes of stem/progenitor cell niches throughout life and trans-interactions between EphB2 produced by corticotropes and ephrin-B2 located in the basolateral cell membranes of stem/progenitor cells in the early postnatal pituitary gland. These data indicate that ephrin-B2 plays a role in pituitary stem/progenitor cell niches by selective interaction with EphB3 in cis and EphB2 in trans.

Distinct roles of neuroepithelial-like and radial glia-like progenitor cells in cerebellar regeneration.

PubMed

Kaslin, Jan; Kroehne, Volker; Ganz, Julia; Hans, Stefan; Brand, Michael

2017-04-15

Zebrafish can regenerate after brain injury, and the regenerative process is driven by resident stem cells. Stem cells are heterogeneous in the vertebrate brain, but the significance of having heterogeneous stem cells in regeneration is not understood. Limited availability of specific stem cells might impair the regeneration of particular cell lineages. We studied regeneration of the adult zebrafish cerebellum, which contains two major stem and progenitor cell types: ventricular zone and neuroepithelial cells. Using conditional lineage tracing we demonstrate that cerebellar regeneration depends on the availability of specific stem cells. Radial glia-like cells are thought to be the predominant stem cell type in homeostasis and after injury. However, we find that radial glia-like cells play a minor role in adult cerebellar neurogenesis and in recovery after injury. Instead, we find that neuroepithelial cells are the predominant stem cell type supporting cerebellar regeneration after injury. Zebrafish are able to regenerate many, but not all, cell types in the cerebellum, which emphasizes the need to understand the contribution of different adult neural stem and progenitor cell subtypes in the vertebrate central nervous system. © 2017. Published by The Company of Biologists Ltd.

Distinct and complementary roles for Aspergillus fumigatus-specific Tr1 and Foxp3+ regulatory T cells in humans and mice

PubMed Central

Bedke, Tanja; Iannitti, Rossana G; De Luca, Antonella; Giovannini, Gloria; Fallarino, Francesca; Berges, Carsten; Latgé, Jean-Paul; Einsele, Hermann; Romani, Luigina; Topp, Max S

2014-01-01

Unlike induced Foxp3+ regulatory T cells (Foxp3+ iTreg) that have been shown to play an essential role in the development of protective immunity to the ubiquitous mold Aspergillus fumigatus, type-(1)-regulatory T cells (Tr1) cells have, thus far, not been implicated in this process. Here, we evaluated the role of Tr1 cells specific for an epitope derived from the cell wall glucanase Crf-1 of A. fumigatus (Crf-1/p41) in antifungal immunity. We identified Crf-1/p41-specific latent-associated peptide+ Tr1 cells in healthy humans and mice after vaccination with Crf-1/p41+zymosan. These cells produced high amounts of interleukin (IL)-10 and suppressed the expansion of antigen-specific T cells in vitro and in vivo. In mice, in vivo differentiation of Tr1 cells was dependent on the presence of the aryl hydrocarbon receptor, c-Maf and IL-27. Moreover, in comparison to Tr1 cells, Foxp3+ iTreg that recognize the same epitope were induced in an interferon gamma-type inflammatory environment and more potently suppressed innate immune cell activities. Overall, our data show that Tr1 cells are involved in the maintenance of antifungal immune homeostasis, and most likely play a distinct, yet complementary, role compared with Foxp3+ iTreg. PMID:24820384

Cell-type-specific roles for COX-2 in UVB-induced skin cancer

PubMed Central

Herschman, Harvey

2014-01-01

In human tumors, and in mouse models, cyclooxygenase-2 (COX-2) levels are frequently correlated with tumor development/burden. In addition to intrinsic tumor cell expression, COX-2 is often present in fibroblasts, myofibroblasts and endothelial cells of the tumor microenvironment, and in infiltrating immune cells. Intrinsic cancer cell COX-2 expression is postulated as only one of many sources for prostanoids required for tumor promotion/progression. Although both COX-2 inhibition and global Cox-2 gene deletion ameliorate ultraviolet B (UVB)-induced SKH-1 mouse skin tumorigenesis, neither manipulation can elucidate the cell type(s) in which COX-2 expression is required for tumorigenesis; both eliminate COX-2 activity in all cells. To address this question, we created Cox-2 flox/flox mice, in which the Cox-2 gene can be eliminated in a cell-type-specific fashion by targeted Cre recombinase expression. Cox-2 deletion in skin epithelial cells of SKH-1 Cox-2 flox/flox;K14Cre + mice resulted, following UVB irradiation, in reduced skin hyperplasia and increased apoptosis. Targeted epithelial cell Cox-2 deletion also resulted in reduced tumor incidence, frequency, size and proliferation rate, altered tumor cell differentiation and reduced tumor vascularization. Moreover, Cox-2 flox/flox;K14Cre + papillomas did not progress to squamous cell carcinomas. In contrast, Cox-2 deletion in SKH-1 Cox-2 flox/flox; LysMCre + myeloid cells had no effect on UVB tumor induction. We conclude that (i) intrinsic epithelial COX-2 activity plays a major role in UVB-induced skin cancer, (ii) macrophage/myeloid COX-2 plays no role in UVB-induced skin cancer and (iii) either there may be another COX-2-dependent prostanoid source(s) that drives UVB skin tumor induction or there may exist a COX-2-independent pathway(s) to UVB-induced skin cancer. PMID:24469308

Cell-type-specific roles for COX-2 in UVB-induced skin cancer.

PubMed

Jiao, Jing; Mikulec, Carol; Ishikawa, Tomo-o; Magyar, Clara; Dumlao, Darren S; Dennis, Edward A; Fischer, Susan M; Herschman, Harvey

2014-06-01

In human tumors, and in mouse models, cyclooxygenase-2 (COX-2) levels are frequently correlated with tumor development/burden. In addition to intrinsic tumor cell expression, COX-2 is often present in fibroblasts, myofibroblasts and endothelial cells of the tumor microenvironment, and in infiltrating immune cells. Intrinsic cancer cell COX-2 expression is postulated as only one of many sources for prostanoids required for tumor promotion/progression. Although both COX-2 inhibition and global Cox-2 gene deletion ameliorate ultraviolet B (UVB)-induced SKH-1 mouse skin tumorigenesis, neither manipulation can elucidate the cell type(s) in which COX-2 expression is required for tumorigenesis; both eliminate COX-2 activity in all cells. To address this question, we created Cox-2(flox/flox) mice, in which the Cox-2 gene can be eliminated in a cell-type-specific fashion by targeted Cre recombinase expression. Cox-2 deletion in skin epithelial cells of SKH-1 Cox-2(flox/flox);K14Cre(+) mice resulted, following UVB irradiation, in reduced skin hyperplasia and increased apoptosis. Targeted epithelial cell Cox-2 deletion also resulted in reduced tumor incidence, frequency, size and proliferation rate, altered tumor cell differentiation and reduced tumor vascularization. Moreover, Cox-2(flox/flox);K14Cre(+) papillomas did not progress to squamous cell carcinomas. In contrast, Cox-2 deletion in SKH-1 Cox-2(flox/flox); LysMCre(+) myeloid cells had no effect on UVB tumor induction. We conclude that (i) intrinsic epithelial COX-2 activity plays a major role in UVB-induced skin cancer, (ii) macrophage/myeloid COX-2 plays no role in UVB-induced skin cancer and (iii) either there may be another COX-2-dependent prostanoid source(s) that drives UVB skin tumor induction or there may exist a COX-2-independent pathway(s) to UVB-induced skin cancer. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Adipose tissue macrophages in the Development of Obesity-induced Inflammation, Insulin Resistance and Type 2 Diabetes

PubMed Central

Lee, Jongsoon

2014-01-01

It has been increasingly accepted that chronic subacute inflammation plays an important role in the development of insulin resistance and Type 2 Diabetes in animals and humans. Particularly supporting this is that suppression of systemic inflammation in Type 2 Diabetes improves glycemic control; this also points to a new potential therapeutic target for the treatment of Type 2 Diabetes. Recent studies strongly suggest that obesity-induced inflammation is mainly mediated by tissue resident immune cells, with particular attention being focused on adipose tissue macrophages (ATMs). This review delineates the current progress made in understanding obesity-induced inflammation and the roles ATMs play in this process. PMID:23397293

Type I Interferon Controls Propagation of Long Interspersed Element-1*

PubMed Central

Yu, Qiujing; Carbone, Christopher J.; Katlinskaya, Yuliya V.; Zheng, Hui; Zheng, Ke; Luo, Mengcheng; Wang, P. Jeremy; Greenberg, Roger A.; Fuchs, Serge Y.

2015-01-01

Type I interferons (IFN) including IFNα and IFNβ are critical for the cellular defense against viruses. Here we report that increased levels of IFNβ were found in testes from mice deficient in MOV10L1, a germ cell-specific RNA helicase that plays a key role in limiting the propagation of retrotransposons including Long Interspersed Element-1 (LINE-1). Additional experiments revealed that activation of LINE-1 retrotransposons increases the expression of IFNβ and of IFN-stimulated genes. Conversely, pretreatment of cells with IFN suppressed the replication of LINE-1. Furthermore, the efficacy of LINE-1 replication was increased in isogenic cell lines harboring inactivating mutations in diverse elements of the IFN signaling pathway. Knockdown of the IFN receptor chain IFNAR1 also stimulated LINE-1 propagation in vitro. Finally, a greater accumulation of LINE-1 was found in mice that lack IFNAR1 compared with wild type mice. We propose that LINE-1-induced IFN plays an important role in restricting LINE-1 propagation and discuss the putative role of IFN in preserving the genome stability. PMID:25716322

Epigenetics in adipose tissue, obesity, weight loss and diabetes

USDA-ARS?s Scientific Manuscript database

Given the role that the diet and other environmental factors play in the development of obesity and type 2 diabetes, the implication of different epigenetic processes is being investigated. Although it is well known that the environmental factors can cause cell type-dependent epigenetic changes, inc...

Type 2 Innate Lymphoid Cells: Friends or Foes—Role in Airway Allergic Inflammation and Asthma

PubMed Central

Pishdadian, Abbas; Varasteh, Abdol-Reza; Sankian, Mojtaba

2012-01-01

Innate-like lymphocytes (ILLs) and innate lymphoid cells (ILCs) are two newly characterized families of lymphocytes with limited and no rearranged antigen receptors, respectively. These soldiers provide a first line of defense against foreign insults by triggering a prompt innate immune response and bridging the gap of innate and adaptive immunity. Type 2 innate lymphoid cells (ILCs2) are newly identified members of the ILC family that play a key role in type 2 immune responses by prompt production of type 2 cytokines (especially IL-5 and IL-13) in response to antigen-induced IL-25/33 and by recruiting type 2 “immune franchise.” Regarding the two different roles of type 2 cytokines, helminth expulsion and type 2-related diseases, here we review the latest advances in ILC2 biology and examine the pivotal role of resident ILCs2 in allergen-specific airway inflammation and asthma. PMID:23209480

Type 2 innate lymphoid cells: friends or foes-role in airway allergic inflammation and asthma.

PubMed

Pishdadian, Abbas; Varasteh, Abdol-Reza; Sankian, Mojtaba

2012-01-01

Innate-like lymphocytes (ILLs) and innate lymphoid cells (ILCs) are two newly characterized families of lymphocytes with limited and no rearranged antigen receptors, respectively. These soldiers provide a first line of defense against foreign insults by triggering a prompt innate immune response and bridging the gap of innate and adaptive immunity. Type 2 innate lymphoid cells (ILCs2) are newly identified members of the ILC family that play a key role in type 2 immune responses by prompt production of type 2 cytokines (especially IL-5 and IL-13) in response to antigen-induced IL-25/33 and by recruiting type 2 "immune franchise." Regarding the two different roles of type 2 cytokines, helminth expulsion and type 2-related diseases, here we review the latest advances in ILC2 biology and examine the pivotal role of resident ILCs2 in allergen-specific airway inflammation and asthma.

Comprehensive Identification of Long Non-coding RNAs in Purified Cell Types from the Brain Reveals Functional LncRNA in OPC Fate Determination.

PubMed

Dong, Xiaomin; Chen, Kenian; Cuevas-Diaz Duran, Raquel; You, Yanan; Sloan, Steven A; Zhang, Ye; Zong, Shan; Cao, Qilin; Barres, Ben A; Wu, Jia Qian

2015-12-01

Long non-coding RNAs (lncRNAs) (> 200 bp) play crucial roles in transcriptional regulation during numerous biological processes. However, it is challenging to comprehensively identify lncRNAs, because they are often expressed at low levels and with more cell-type specificity than are protein-coding genes. In the present study, we performed ab initio transcriptome reconstruction using eight purified cell populations from mouse cortex and detected more than 5000 lncRNAs. Predicting the functions of lncRNAs using cell-type specific data revealed their potential functional roles in Central Nervous System (CNS) development. We performed motif searches in ENCODE DNase I digital footprint data and Mouse ENCODE promoters to infer transcription factor (TF) occupancy. By integrating TF binding and cell-type specific transcriptomic data, we constructed a novel framework that is useful for systematically identifying lncRNAs that are potentially essential for brain cell fate determination. Based on this integrative analysis, we identified lncRNAs that are regulated during Oligodendrocyte Precursor Cell (OPC) differentiation from Neural Stem Cells (NSCs) and that are likely to be involved in oligodendrogenesis. The top candidate, lnc-OPC, shows highly specific expression in OPCs and remarkable sequence conservation among placental mammals. Interestingly, lnc-OPC is significantly up-regulated in glial progenitors from experimental autoimmune encephalomyelitis (EAE) mouse models compared to wild-type mice. OLIG2-binding sites in the upstream regulatory region of lnc-OPC were identified by ChIP (chromatin immunoprecipitation)-Sequencing and validated by luciferase assays. Loss-of-function experiments confirmed that lnc-OPC plays a functional role in OPC genesis. Overall, our results substantiated the role of lncRNA in OPC fate determination and provided an unprecedented data source for future functional investigations in CNS cell types. We present our datasets and analysis results via the interactive genome browser at our laboratory website that is freely accessible to the research community. This is the first lncRNA expression database of collective populations of glia, vascular cells, and neurons. We anticipate that these studies will advance the knowledge of this major class of non-coding genes and their potential roles in neurological development and diseases.

Type two innate lymphoid cells: the Janus cells in health and disease.

PubMed

Maazi, Hadi; Akbari, Omid

2017-07-01

Innate lymphoid cells are functionally diverse subsets of immune cells including the conventional natural killer cells, lymphoid tissue inducers, type 1, 2, and 3 with significant roles in immunity and pathogenesis of inflammatory diseases. Type 2 innate lymphoid cells (ILC2s) resemble type 2 helper (Th2) cells in cytokine production and contribute to anti-helminth immunity, maintaining mucosal tissue integrity, and adipose tissue browning. ILC2s play important roles in the pathogenesis of allergic diseases and asthma. Studying the pathways of activation and regulation of ILC2s are currently a priority for giving a better understanding of pathogenesis of diseases with immunological roots. Recently, our laboratory and others have shown several pathways of regulation of ILC2s by co-stimulatory molecules such as ICOS, regulatory T cells and by compounds such as nicotine. In this review, we summarize the current understanding of the mechanisms of activation and regulation of ILC2s and the role of these cells in health and disease. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Redox regulation of epithelial sodium channels examined in alveolar type 1 and 2 cells patch-clamped in lung slice tissue.

PubMed

Helms, My N; Jain, Lucky; Self, Julie L; Eaton, Douglas C

2008-08-15

The alveolar surface of the lung is lined by alveolar type 1 (AT1) and type 2 (AT2) cells. Using single channel patch clamp analysis in lung slice preparations, we are able to uniquely study AT1 and AT2 cells separately from intact lung. We report for the first time the Na+ transport properties of type 2 cells accessed in live lung tissue (as we have done in type 1 cells). Type 2 cells in lung tissue slices express both highly selective cation and nonselective cation channels with average conductances of 8.8 +/- 3.2 and 22.5 +/- 6.3 picosiemens, respectively. Anion channels with 10-picosiemen conductance are also present in the apical membrane of type 2 cells. Our lung slice studies importantly verify the use of cultured cell model systems commonly used in lung epithelial sodium channel (ENaC) studies. Furthermore, we identify novel functional differences between the cells that make up the alveolar epithelium. One important difference is that exposure to the nitric oxide (NO) donor, PAPA-NONOate (1.5 microm), significantly decreases average ENaC NPo in type 2 cells (from 1.38 +/- 0.26 to 0.82 +/- 0.16; p < 0.05 and n = 18) but failed to alter ENaC activity in alveolar type 1 cells. Elevating endogenous superoxide (O2.) levels with Ethiolat, a superoxide dismutase inhibitor, prevented NO inhibition of ENaC activity in type 2 cells, supporting the novel hypothesis that O2. and NO signaling plays an important role in maintaining lung fluid balance.

Heterogeneity of Human CD4(+) T Cells Against Microbes.

PubMed

Sallusto, Federica

2016-05-20

CD4(+) T helper (Th) cells play a central role in the adaptive immune response by providing help to B cells and cytotoxic T cells and by releasing different types of cytokines in tissues to mediate protection against a wide range of pathogenic microorganisms. These functions are performed by different types of Th cells endowed with distinct migratory capacities and effector functions. Here we discuss how studies of the human T cell response to microbes have advanced our understanding of Th cell functional heterogeneity, in particular with the discovery of a distinct Th1 subset involved in the response to Mycobacteria and the characterization of two types of Th17 cells specific for extracellular bacteria or fungi. We also review new approaches to dissect at the clonal level the human CD4(+) T cell response induced by pathogens or vaccines that have revealed an unexpected degree of intraclonal diversification and propose a progressive and selective model of CD4(+) T cell differentiation.

CXCR6 Plays a Critical Role in Angiotensin II-induced Renal Injury and Fibrosis

PubMed Central

Xia, Yunfeng; Jin, Xiaogao; Yan, Jingyin; Entman, Mark L.; Wang, Yanlin

2014-01-01

Objective Recent studies have shown that angiotensin II (Ang II) plays a critical role in the pathogenesis and progression of hypertensive kidney disease. However, the signaling mechanisms are poorly understood. In this study, we investigated the role of CXCR6 in Ang II-induced renal injury and fibrosis. Approach and Results Wild-type and CXCR6-GFP knockin mice were treated with Ang II via subcutaneous osmotic minipumps at 1500 ng/kg/min after unilateral nephrectomy for up to 4 weeks. WT and CXCR6-GFP knockin mice had virtually identical blood pressure at baseline. Ang II treatment led to an increase in blood pressure that was similar between WT and CXCR6-GFP knockin mice. CXCR6-GFP knockin mice were protected from Ang II-induced renal dysfunction, proteinuria, and fibrosis. CXCR6-GFP knockin mice accumulated fewer bone marrow-derived fibroblasts and myofibroblasts and produced less extracellular matrix protein in the kidneys following Ang II treatment. Furthermore, CXCR6-GFP knockin mice exhibited fewer F4/80+ macrophages and CD3+ T cells and expressed less proinflammatory cytokines in the kidneys after Ang II treatment. Finally, wild-type mice engrafted with CXCR6−/− bone marrow cells displayed fewer bone marrow-derived fibroblasts, macrophages, and T cells in the kidney after Ang II treatment compared with wild-type mice engrafted with CXCR6+/+ bone marrow cells. Conclusions Our results indicate that CXCR6 plays a pivotal role in the development of Ang II-induced renal injury and fibrosis through regulation of macrophage and T cell infiltration and bone marrow-derived fibroblast accumulation. PMID:24855055

Role of Non-Myocyte Gap Junctions and Connexin Hemichannels in Cardiovascular Health and Disease: Novel Therapeutic Targets?

PubMed

Johnson, Robert D; Camelliti, Patrizia

2018-03-15

The heart is a complex organ composed of multiple cell types, including cardiomyocytes and different non-myocyte populations, all working closely together to determine the hearts properties and maintain normal cardiac function. Connexins are abundantly expressed proteins that form plasma membrane hemichannels and gap junctions between cells. Gap junctions are intracellular channels that allow for communication between cells, and in the heart they play a crucial role in cardiac conduction by coupling adjacent cardiomyocytes. Connexins are expressed in both cardiomyocytes and non-myocytes, including cardiac fibroblasts, endothelial cells, and macrophages. Non-myocytes are the largest population of cells in the heart, and therefore it is important to consider what roles connexins, hemichannels, and gap junctions play in these cell types. The aim of this review is to provide insight into connexin-based signalling in non-myocytes during health and disease, and highlight how targeting these proteins could lead to the development of novel therapies. We conclude that connexins in non-myocytes contribute to arrhythmias and adverse ventricular remodelling following myocardial infarction, and are associated with the initiation and development of atherosclerosis. Therefore, therapeutic interventions targeting these connexins represent an exciting new research avenue with great potential.

HLA-E–restricted regulatory CD8+ T cells are involved in development and control of human autoimmune type 1 diabetes

PubMed Central

Jiang, Hong; Canfield, Steve M.; Gallagher, Mary P.; Jiang, Hong H.; Jiang, Yihua; Zheng, Zongyu; Chess, Leonard

2010-01-01

A key feature of the immune system is its ability to discriminate self from nonself. Breakdown in any of the mechanisms that maintain unresponsiveness to self (a state known as self-tolerance) contributes to the development of autoimmune conditions. Recent studies in mice show that CD8+ T cells specific for the unconventional MHC class I molecule Qa-1 bound to peptides derived from the signal sequence of Hsp60 (Hsp60sp) contribute to self/nonself discrimination. However, it is unclear whether they exist in humans and play a role in human autoimmune diseases. Here we have shown that CD8+ T cells specific for Hsp60sp bound to HLA-E (the human homolog of Qa-1) exist and play an important role in maintaining peripheral self-tolerance by discriminating self from nonself in humans. Furthermore, in the majority of type 1 diabetes (T1D) patients tested, there was a specific defect in CD8+ T cell recognition of HLA-E/Hsp60sp, which was associated with failure of self/nonself discrimination. However, the defect in the CD8+ T cells from most of the T1D patients tested could be corrected in vitro by exposure to autologous immature DCs loaded with the Hsp60sp peptide. These data suggest that HLA-E–restricted CD8+ T cells may play an important role in keeping self-reactive T cells in check. Thus, correction of this defect could be a potentially effective and safe approach in the therapy of T1D. PMID:20877010

Stem cells in the canine pituitary gland and in pituitary adenomas.

PubMed

van Rijn, Sarah J; Tryfonidou, Marianna A; Hanson, Jeanette M; Penning, Louis C; Meij, Björn P

2013-12-01

Cushing's disease (CD) or pituitary-dependent hypercortisolism is a common endocrinopathy in dogs, with an estimated prevalence of 1 or 2 in 1000 dogs per year. It is caused by an adrenocorticotropic hormone secreting adenoma in the pars distalis or pars intermedia of the pituitary gland. The pituitary gland is a small endocrine gland located in the pituitary fossa. In the postnatal individual, the hypothalamus-pituitary axis plays a central role in maintaining homeostatic functions, like control of metabolism, reproduction, and growth. Stem cells are suggested to play a role in the homeostatic adaptations of the adult pituitary gland, such as the rapid specific cell-type expansion in response to pregnancy or lactation. Several cell populations have been suggested as pituitary stem cells, such as Side Population cells and cells expressing Sox2 or Nestin. These cell populations are discussed in this review. Also, stem and progenitor cells are thought to play a role in pituitary tumorigenesis, such as the development of pituitary adenomas in dogs. There are limited reports on the role of stem cells in pituitary adenomas, especially in dogs. Further studies are needed to identify and characterize this cell population and to develop specific cell targeting therapeutic strategies as a new way of treating canine CD.

Disease-Associated Plasmacytoid Dendritic Cells

PubMed Central

Li, Shuang; Wu, Jing; Zhu, Shan; Liu, Yong-Jun; Chen, Jingtao

2017-01-01

Plasmacytoid dendritic cells (pDCs), also called natural interferon (IFN)-producing cells, represent a specialized cell type within the innate immune system. pDCs are specialized in sensing viral RNA and DNA by toll-like receptor-7 and -9 and have the ability to rapidly produce massive amounts of type 1 IFNs upon viral encounter. After producing type 1 IFNs, pDCs differentiate into professional antigen-presenting cells, which are capable of stimulating T cells of the adaptive immune system. Chronic activation of human pDCs by self-DNA or mitochondrial DNA contributes to the pathogenesis of systemic lupus erythematosis and IFN-related autoimmune diseases. Under steady-state conditions, pDCs play an important role in immune tolerance. In many types of human cancers, recruitment of pDCs to the tumor microenvironment contributes to the induction of immune tolerance. Here, we provide a systemic review of recent progress in studies on the role of pDCs in human diseases, including cancers and autoimmune/inflammatory diseases. PMID:29085361

NITRIC OXIDE, MITOCHONDRIAL HYPERPOLARIZATION AND T-CELL ACTIVATION

PubMed Central

Nagy, Gyorgy; Koncz, Agnes; Fernandez, David; Perl, Andras

2007-01-01

T lymphocyte activation is associated with nitric oxide (NO) production that plays an essential role in multiple T cell functions. NO acts as a messenger, activating soluble guanyl cyclase and participating in the transduction signaling pathways involving cyclic GMP. NO modulates mitochondrial events that are involved in apoptosis and regulates mitochondrial membrane potential and mitochondrial biogenesis in many cell types, including lymphocytes. Mitochondrial hyperpolarization (MHP), an early and reversible event during both T lymphocyte activation and apoptosis, is regulated by NO. Here, we discuss recent evidence that NO-induced MHP represents a molecular switch in multiple T cell signaling pathways. Overproduction of NO in systemic lupus erythematosus (SLE) induces mitochondrial biogenesis and alters Ca2+ signaling. Thus, while NO plays a physiological role in lymphocyte cell signaling, its overproduction may disturb normal T cell function, contributing to the pathogenesis of autoimmunity. PMID:17462531

The role of alveolar epithelial cells in initiating and shaping pulmonary immune responses: communication between innate and adaptive immune systems.

PubMed

Chuquimia, Olga D; Petursdottir, Dagbjort H; Rahman, Muhammad J; Hartl, Katharina; Singh, Mahavir; Fernández, Carmen

2012-01-01

Macrophages and dendritic cells have been recognized as key players in the defense against mycobacterial infection. However, more recently, other cells in the lungs such as alveolar epithelial cells (AEC) have been found to play important roles in the defense and pathogenesis of infection. In the present study we first compared AEC with pulmonary macrophages (PuM) isolated from mice in their ability to internalize and control Bacillus Calmette-Guérin (BCG) growth and their capacity as APCs. AEC were able to internalize and control bacterial growth as well as present antigen to primed T cells. Secondly, we compared both cell types in their capacity to secrete cytokines and chemokines upon stimulation with various molecules including mycobacterial products. Activated PuM and AEC displayed different patterns of secretion. Finally, we analyzed the profile of response of AEC to diverse stimuli. AEC responded to both microbial and internal stimuli exemplified by TLR ligands and IFNs, respectively. The response included synthesis by AEC of several factors, known to have various effects in other cells. Interestingly, TNF could stimulate the production of CCL2/MCP-1. Since MCP-1 plays a role in the recruitment of monocytes and macrophages to sites of infection and macrophages are the main producers of TNF, we speculate that both cell types can stimulate each other. Also, another cell-cell interaction was suggested when IFNs (produced mainly by lymphocytes) were able to induce expression of chemokines (IP-10 and RANTES) by AEC involved in the recruitment of circulating lymphocytes to areas of injury, inflammation, or viral infection. In the current paper we confirm previous data on the capacity of AEC regarding internalization of mycobacteria and their role as APC, and extend the knowledge of AEC as a multifunctional cell type by assessing the secretion of a broad array of factors in response to several different types of stimuli.

Morphological and physiological analysis of type-5 and other bipolar cells in the Mouse Retina.

PubMed

Hellmer, C B; Zhou, Y; Fyk-Kolodziej, B; Hu, Z; Ichinose, T

2016-02-19

Retinal bipolar cells are second-order neurons in the visual system, which initiate multiple image feature-based neural streams. Among more than ten types of bipolar cells, type-5 cells are thought to play a role in motion detection pathways. Multiple subsets of type-5 cells have been reported; however, detailed characteristics of each subset have not yet been elucidated. Here, we found that they exhibit distinct morphological features as well as unique voltage-gated channel expression. We have conducted electrophysiological and immunohistochemical analysis of retinal bipolar cells. We defined type-5 cells by their axon terminal ramification in the inner plexiform layer between the border of ON/OFF sublaminae and the ON choline acetyltransferase (ChAT) band. We found three subsets of type-5 cells: XBCs had the widest axon terminals that stratified at a close approximation of the ON ChAT band as well as exhibiting large voltage-gated Na(+) channel activity, type-5-1 cells had compact terminals and no Na(+) channel activity, and type-5-2 cells contained umbrella-shaped terminals as well as large voltage-gated Na(+) channel activity. Hyperpolarization-activated cyclic nucleotide-gated (HCN) currents were also evoked in all type-5 bipolar cells. We found that XBCs and type-5-2 cells exhibited larger HCN currents than type-5-1 cells. Furthermore, the former two types showed stronger HCN1 expression than the latter. Our previous observations (Ichinose et al., 2014) match the current study: low temporal tuning cells that we named 5S corresponded to 5-1 in this study, while high temporal tuning 5f cells from the previous study corresponded to 5-2 cells. Taken together, we found three subsets of type-5 bipolar cells based on their morphologies and physiological features. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

Development of coin-type cell and engineering of its compartments for rechargeable seawater batteries

NASA Astrophysics Data System (ADS)

Han, Jinhyup; Hwang, Soo Min; Go, Wooseok; Senthilkumar, S. T.; Jeon, Donghoon; Kim, Youngsik

2018-01-01

Cell design and optimization of the components, including active materials and passive components, play an important role in constructing robust, high-performance rechargeable batteries. Seawater batteries, which utilize earth-abundant and natural seawater as the active material in an open-structured cathode, require a new platform for building and testing the cells other than typical Li-ion coin-type or pouch-type cells. Herein, we present new findings based on our optimized cell. Engineering the cathode components-improving the wettability of cathode current collector and seawater catholyte flow-improves the battery performance (voltage efficiency). Optimizing the cell component and design is the key to identifying the electrochemical processes and reactions of active materials. Hence, the outcome of this research can provide a systematic study of potentially active materials used in seawater batteries and their effectiveness on the electrochemical performance.

Five Xanthomonas type III effectors suppress cell death induced by components of immunity-associated MAP kinase cascades

PubMed Central

Teper, Doron; Sunitha, Sukumaran; Martin, Gregory B; Sessa, Guido

2015-01-01

Mitogen-activated protein kinase (MAPK) cascades play a fundamental role in signaling of plant immunity and mediate elicitation of cell death. Xanthomonas spp. manipulate plant signaling by using a type III secretion system to deliver effector proteins into host cells. We examined the ability of 33 Xanthomonas effectors to inhibit cell death induced by overexpression of components of MAPK cascades in Nicotiana benthamiana plants. Five effectors inhibited cell death induced by overexpression of MAPKKKα and MEK2, but not of MAP3Kϵ. In addition, expression of AvrBs1 in yeast suppressed activation of the high osmolarity glycerol MAPK pathway, suggesting that the target of this effector is conserved in eukaryotic organisms. These results indicate that Xanthomonas employs several type III effectors to suppress immunity-associated cell death mediated by MAPK cascades. PMID:26237448

B cells promote inflammation in obesity and type 2 diabetes through regulation of T-cell function and an inflammatory cytokine profile

PubMed Central

DeFuria, Jason; Belkina, Anna C.; Jagannathan-Bogdan, Madhumita; Snyder-Cappione, Jennifer; Carr, Jordan David; Nersesova, Yanina R.; Markham, Douglas; Strissel, Katherine J.; Watkins, Amanda A.; Zhu, Min; Allen, Jessica; Bouchard, Jacqueline; Toraldo, Gianluca; Jasuja, Ravi; Obin, Martin S.; McDonnell, Marie E.; Apovian, Caroline; Denis, Gerald V.; Nikolajczyk, Barbara S.

2013-01-01

Patients with type 2 diabetes (T2D) have disease-associated changes in B-cell function, but the role these changes play in disease pathogenesis is not well established. Data herein show B cells from obese mice produce a proinflammatory cytokine profile compared with B cells from lean mice. Complementary in vivo studies show that obese B cell–null mice have decreased systemic inflammation, inflammatory B- and T-cell cytokines, adipose tissue inflammation, and insulin resistance (IR) compared with obese WT mice. Reduced inflammation in obese/insulin resistant B cell–null mice associates with an increased percentage of anti-inflammatory regulatory T cells (Tregs). This increase contrasts with the sharply decreased percentage of Tregs in obese compared with lean WT mice and suggests that B cells may be critical regulators of T-cell functions previously shown to play important roles in IR. We demonstrate that B cells from T2D (but not non-T2D) subjects support proinflammatory T-cell function in obesity/T2D through contact-dependent mechanisms. In contrast, human monocytes increase proinflammatory T-cell cytokines in both T2D and non-T2D analyses. These data support the conclusion that B cells are critical regulators of inflammation in T2D due to their direct ability to promote proinflammatory T-cell function and secrete a proinflammatory cytokine profile. Thus, B cells are potential therapeutic targets for T2D. PMID:23479618

Zic deficiency in the cortical marginal zone and meninges results in cortical lamination defects resembling those in type II lissencephaly.

PubMed

Inoue, Takashi; Ogawa, Masaharu; Mikoshiba, Katsuhiko; Aruga, Jun

2008-04-30

The formation of the highly organized cortical structure depends on the production and correct placement of the appropriate number and types of neurons. The Zic family of zinc-finger transcription factors plays essential roles in regulating the proliferation and differentiation of neuronal progenitors in the medial forebrain and the cerebellum. Examination of the expression of Zic genes demonstrated that Zic1, Zic2, and Zic3 were expressed by the progenitor cells in the septum and cortical hem, the sites of generation of the Cajal-Retzius (CR) cells. Immunohistochemical studies have revealed that Zic proteins were abundantly expressed in the meningeal cells and that the majority of the CR cells distributed in the medial and dorsal cortex also expressed Zic proteins in the mid-late embryonic and postnatal cortical marginal zones. During embryonic cortical development, Zic1/Zic3 double-mutant and hypomorphic Zic2 mutant mice showed a reduction in the number of CR cells in the rostral cortex, whereas the cell number remained unaffected in the caudal cortex. These mutants also showed mislocalization of the CR cells and cortical lamination defects, resembling the changes noted in type II (cobblestone) lissencephaly, throughout the brain. In the Zic1/3 mutant, reduced proliferation of the meningeal cells was observed before the thinner and disrupted organization of the pial basement membrane (BM) with reduced expression of the BM components and the meningeal cell-derived secretory factor. These defects correlated with the changes in the end feet morphology of the radial glial cells. These findings indicate that the Zic genes play critical roles in cortical development through regulating the proliferation of meningeal cells and the pial BM assembly.

2'-5' Oligoadenylate synthetase-like 1 (OASL1) deficiency in mice promotes an effective anti-tumor immune response by enhancing the production of type I interferons.

PubMed

Sim, Chan Kyu; Cho, Yeon Sook; Kim, Byung Soo; Baek, In-Jeoung; Kim, Young-Joon; Lee, Myeong Sup

2016-06-01

Type I interferon (IFN-I) plays a critical role in antiviral and antitumor defense. In our previous studies, we showed that IFN-I-inducible 2'-5' oligoadenylate synthetase-like 1 (OASL1) negatively regulates IFN-I production upon viral infection by specifically inhibiting translation of the IFN-I-regulating master transcription factor, interferon regulatory factor 7 (IRF7). In this study, we investigated whether OASL1 plays a negative role in the anti-tumor immune response by using OASL1-deficient (Oasl1 (-/-)) mice and transplantable syngeneic tumor cell models. We found that Oasl1 (-/-) mice demonstrate enhanced resistance to lung metastatic tumors and subcutaneously implanted tumors compared to wild-type (WT) mice. Additionally, we found that cytotoxic effector cells such as CD8(+) T cells (including tumor antigen-specific CD8(+) T cells) and NK cells as well as CD8α(+) DCs (the major antigen cross-presenting cells) were much more frequent (>fivefold) in the Oasl1 (-/-) mouse tumors. Furthermore, the cytotoxic effector cells in Oasl1 (-/-) mouse tumors seemed to be more functionally active. However, the proportion of immunosuppressive myeloid-derived suppressor cells within hematopoietic cells and of regulatory T cells within CD4(+) T cells in Oasl1 (-/-) mouse tumors did not differ significantly from that of WT mice. Tumor-challenged Oasl1 (-/-) mice expressed increased levels of IFN-I and IRF7 protein in the growing tumor, indicating that the enhanced antitumor immune response observed in Oasl1 (-/-) mice was caused by higher IFN-I production in Oasl1 (-/-) mice. Collectively, these results show that OASL1 deficiency promotes the antitumor immune response, and thus, OASL1 could be a good therapeutic target for treating tumors.

Impact of mechanical stretch on the cell behaviors of bone and surrounding tissues

PubMed Central

Yu, Hye-Sun; Kim, Jung-Ju; Kim, Hae-Won; Lewis, Mark P; Wall, Ivan

2016-01-01

Mechanical loading is recognized to play an important role in regulating the behaviors of cells in bone and surrounding tissues in vivo. Many in vitro studies have been conducted to determine the effects of mechanical loading on individual cell types of the tissues. In this review, we focus specifically on the use of the Flexercell system as a tool for studying cellular responses to mechanical stretch. We assess the literature describing the impact of mechanical stretch on different cell types from bone, muscle, tendon, ligament, and cartilage, describing individual cell phenotype responses. In addition, we review evidence regarding the mechanotransduction pathways that are activated to potentiate these phenotype responses in different cell populations. PMID:26977284

The role of the innate immune system in destruction of pancreatic beta cells in NOD mice and humans with type I diabetes

PubMed Central

Tai, Ningwen; Wong, F. Susan; Wen, Li

2016-01-01

Type 1 diabetes (T1D) is an organ-specific autoimmune disease characterized by T cell-mediated destruction of the insulin-producing pancreatic β cells. A combination of genetic and environmental factors eventually leads to the loss of functional β cells mass and hyperglycemia. Both innate and adaptive immunity are involved in the development of T1D. In this review, we have highlighted the most recent findings on the role of innate immunity, especially the pattern recognition receptors (PRRs), in disease development. In murine models and human studies, different PRRs, such as toll-like receptors (TLRs) and nucleotide-binding domain, leucine-rich repeat-containing (or NOD-like) receptors (NLRs), have different roles in the pathogenesis of T1D. These PRRs play a critical role in defending against infection by sensing specific ligands derived from exogenous microorganisms to induce innate immune responses and shape adaptive immunity. Animal studies have shown that TLR7, TLR9, MyD88 and NLPR3 play a disease-predisposing role in T1D, while controversial results have been found with other PRRs, such as TLR2, TLR3, TLR4, TLR5 and others. Human studies also shown that TLR2, TLR3 and TLR4 are expressed in either islet β cells or infiltrated immune cells, indicating the innate immunity plays a role in β cell autoimmunity. Furthermore, some human genetic studies showed a possible association of TLR3, TLR7, TLR8 or NLRP3 genes, at single nucleotide polymorphism (SNP) level, with human T1D. Increasing evidence suggest that the innate immunity modulates β cell autoimmunity. Thus, targeting pathways of innate immunity may provide novel therapeutic strategies to fight this disease. PMID:27021275

Expression and subcellular localization of the ryanodine receptor in rat pancreatic acinar cells.

PubMed Central

Leite, M F; Dranoff, J A; Gao, L; Nathanson, M H

1999-01-01

The ryanodine receptor (RyR) is the principal Ca2+-release channel in excitable cells, whereas the inositol 1,4,5-trisphosphate (InsP3) receptor (InsP3R) is primarily responsible for Ca2+ release in non-excitable cells, including epithelia. RyR also is expressed in a number of non-excitable cell types, but is thought to serve as an auxiliary or alternative Ca2+-release pathway in those cells. Here we use reverse transcription PCR to show that a polarized epithelium, the pancreatic acinar cell, expresses the type 2, but not the type 1 or 3, isoform of RyR. We furthermore use immunochemistry to demonstrate that the type 2 RyR is distributed throughout the basolateral and, to a lesser extent, the apical region of the acinar cell, but is excluded from the trigger zone, where cytosolic Ca2+ signals originate in this cell type. Since propagation of Ca2+ waves in acinar cells is sensitive to ryanodine, caffeine and Ca2+, these findings suggest that Ca2+ waves in this cell type result from the co-ordinated release of Ca2+, first from InsP3Rs in the trigger zone, then from RyRs elsewhere in the cell. RyR may play a fundamental role in Ca2+ signalling in polarized epithelia, including for Ca2+ signals initiated by InsP3. PMID:9882629

Role of Type 2 Innate Lymphoid Cells in Allergic Diseases.

PubMed

Cosmi, Lorenzo; Liotta, Francesco; Maggi, Laura; Annunziato, Francesco

2017-09-11

The adaptive immune response orchestrated by type 2 T helper (Th2) lymphocytes, strictly cooperates with the innate response of group 2 innate lymphoid cells (ILC2), in the protection from helminths infection, as well as in the pathogenesis of allergic disease. The aim of this review is to explore the pathogenic role of ILC2 in different type 2-mediated disorders. Recent studies have shown that epithelial cell-derived cytokines and their responding cells, ILC2, play a pathogenic role in bronchial asthma, chronic rhinosinusitis, and atopic dermatitis. The growing evidences of the contribution of ILC2 in the induction and maintenance of allergic inflammation in such disease suggest the possibility to target them in therapy. Biological therapies blocking ILC2 activation or neutralizing their effector cytokines are currently under evaluation to be used in patients with type 2-dominated diseases.

[Generation of functional organs from pluripotent stem cells].

PubMed

Miyamoto, Tatsuyuki; Nakauchi, Hiromitsu

2015-10-01

Hematopoietic stem cells (HSCs) have played a major role in stem cell biology, providing many conceptual ideas and models. Among them is the concept of the "niche", a special bone-marrow microenvironment that by exchanging cues regulates stem-cell fate. The HSC niche also plays an important role in HSC transplantation. Successful engraftment of donor HSCs depends on myeloablative pretreatment to empty the niche. The concept of the stem-cell niche has now been extended to the generation of organs. We postulated that an empty "organ niche" exists in a developing animal when development of an organ is genetically disabled. This organ niche should be developmentally compensated by blastocyst complementation using wild-type primary stem cells (PSCs). We proved the principle of organogenesis from xenogeneic PSCs in an embryo unable to form a specific organ, demonstrating the generation of functionally normal rat pancreas by injecting rat PSCs into pancreatogenesis-disabled mouse embryos. This principle has held in pigs. When pancreatogenesis-disabled pig embryos underwent complementation with blastomeres from wild-type pig embryos to produce chimeric pigs, the chimeras had normal pancreata and survived to adulthood. Demonstration of the generation of a functional organ from PSCs in pigs is a very important step toward generation of human cells, tissues, and organs from individual patients' own PSCs in large animals.

Nanomechanics of multidomain neuronal cell adhesion protein contactin revealed by single molecule AFM and SMD.

PubMed

Mikulska-Ruminska, Karolina; Kulik, Andrej J; Benadiba, Carine; Bahar, Ivet; Dietler, Giovanni; Nowak, Wieslaw

2017-08-18

Contactin-4 (CNTN4) is a complex cell adhesion molecule (CAM) localized at neuronal membranes, playing a key role in maintaining the mechanical integrity and signaling properties of the synapse. CNTN4 consists of six immunoglobulin C2 type (IgC2) domains and four fibronectin type III (FnIII) domains that are shared with many other CAMs. Mutations in CNTN4 gene have been linked to various psychiatric disorders. Toward elucidating the response of this modular protein to mechanical stress, we studied its force-induced unfolding using single molecule atomic force microscopy (smAFM) and steered molecular dynamics (SMD) simulations. Extensive smAFM and SMD data both indicate the distinctive mechanical behavior of the two types of modules distinguished by unique force-extension signatures. The data also reveal the heterogeneity of the response of the individual FNIII and IgC2 modules, which presumably plays a role in the adaptability of CNTN4 to maintaining cell-cell communication and adhesion properties under different conditions. Results show that extensive sampling of force spectra, facilitated by robot-enhanced AFM, can help reveal the existence of weak stabilizing interactions between the domains of multidomain proteins, and provide insights into the nanomechanics of such multidomain or heteromeric proteins.

ICAM-3 influences human immunodeficiency virus type 1 replication in CD4+ T-cells independent of DC-SIGN-mediated transmission

PubMed Central

Biggins, Julia E.; Biesinger, Tasha; Yu Kimata, Monica T.; Arora, Reetakshi; Kimata, Jason T.

2007-01-01

We investigated the role of ICAM-3 in DC-SIGN-mediated human immunodeficiency virus (HIV) infection of CD4+ T cells. Our results demonstrate that ICAM-3 does not appear to play a role in DC-SIGN-mediated infection of CD4+ T cells as virus is transmitted equally to ICAM-3+ or ICAM-3− Jurkat T cells. However, HIV-1 replication is enhanced in ICAM-3− cells, suggesting that ICAM-3 may limit HIV-1 replication. Similar results were obtained when SIV replication was examined in ICAM-3+ and ICAM-3− CEMx174 cells. Furthermore, while ICAM-3 has been proposed to play a co-stimulatory role in T cell activation, DC-SIGN expression on antigen presenting cells did not enhance antigen-dependent activation of T cells. Together, these data indicate that while ICAM-3 may influence HIV-1 replication, it does so independent of DC-SIGN mediated virus transmission or activation of CD4+ T cells. PMID:17434553

Dendritic cells and anergic type I NKT cells play a crucial role in sulfatide-mediated immune regulation in experimental autoimmune encephalomyelitis

PubMed Central

Maricic, Igor; Halder, Ramesh; Bischof, Felix; Kumar, Vipin

2014-01-01

CD1d-restricted NKT cells can be divided into two groups: type I NKT cells utilize a semi-invariant TCR whereas type II express a relatively diverse set of TCRs. A major subset of type II NKT cells recognizes myelin-derived sulfatides and is selectively enriched in the central nervous system tissue during experimental autoimmune encephalomyelitis (EAE). We have shown that activation of sulfatide-reactive type II NKT cells by sulfatide prevents induction of EAE. Here we have addressed the mechanism of regulation as well as whether a single immunodominant form of synthetic sulfatide can treat ongoing chronic and relapsing EAE in SJL/J mice. We have shown that the activation of sulfatide-reactive type II NKT cells leads to a significant reduction in the frequency and effector function of PLP139-151/I-As–tetramer+ cells in lymphoid and CNS tissues. In addition, type I NKT cells and dendritic cells in the periphery as well as CNS-resident microglia are inactivated following sulfatide administration, and mice deficient in type I NKT cells are not protected from disease. Moreover tolerized DCs from sulfatide-treated animals can adoptively transfer protection into naive mice. Treatment of SJL/J mice with a synthetic cis-tetracosenoyl sulfatide, but not αGalCer, reverses ongoing chronic and relapsing EAE. Our data highlight a novel immune regulatory pathway involving NKT subset interactions leading to inactivation of type I NKT cells, DCs, and microglial cells in suppression of autoimmunity. Since CD1 molecules are non-polymorphic, the sulfatide-mediated immune regulatory pathway can be targeted for development of non-HLA-dependent therapeutic approaches to T cell-mediated autoimmune diseases. PMID:24973441

Immune response of T cells during herpes simplex virus type 1 (HSV-1) infection.

PubMed

Zhang, Jie; Liu, Huan; Wei, Bin

Herpes simplex virus type 1 (HSV-1), a neurotropic member of the alphaherpes virus family, is among the most prevalent and successful human pathogens. HSV-1 can cause serious diseases at every stage of life including fatal disseminated disease in newborns, cold sores, eye disease, and fatal encephalitis in adults. HSV-1 infection can trigger rapid immune responses, and efficient inhibition and clearance of HSV-1 infection rely on both the innate and adaptive immune responses of the host. Multiple strategies have been used to restrict host innate immune responses by HSV-1 to facilitate its infection in host cells. The adaptive immunity of the host plays an important role in inhibiting HSV-1 infections. The activation and regulation of T cells are the important aspects of the adaptive immunity. They play a crucial role in host-mediated immunity and are important for clearing HSV-1. In this review, we examine the findings on T cell immune responses during HSV-1 infection, which hold promise in the design of new vaccine candidates for HSV-1.

Immune response of T cells during herpes simplex virus type 1 (HSV-1) infection*

PubMed Central

Zhang, Jie; Liu, Huan; Wei, Bin

2017-01-01

Herpes simplex virus type 1 (HSV-1), a neurotropic member of the alphaherpes virus family, is among the most prevalent and successful human pathogens. HSV-1 can cause serious diseases at every stage of life including fatal disseminated disease in newborns, cold sores, eye disease, and fatal encephalitis in adults. HSV-1 infection can trigger rapid immune responses, and efficient inhibition and clearance of HSV-1 infection rely on both the innate and adaptive immune responses of the host. Multiple strategies have been used to restrict host innate immune responses by HSV-1 to facilitate its infection in host cells. The adaptive immunity of the host plays an important role in inhibiting HSV-1 infections. The activation and regulation of T cells are the important aspects of the adaptive immunity. They play a crucial role in host-mediated immunity and are important for clearing HSV-1. In this review, we examine the findings on T cell immune responses during HSV-1 infection, which hold promise in the design of new vaccine candidates for HSV-1. PMID:28378566

Mechanisms Restricting Diffusion of Intracellular cAMP.

PubMed

Agarwal, Shailesh R; Clancy, Colleen E; Harvey, Robert D

2016-01-22

Although numerous receptors stimulate cAMP production in a wide array of cells, many elicit distinct, highly localized responses, implying that the subcellular distribution of cAMP is not uniform. One often used explanation is that phosphodiesterases, which breakdown cAMP, act as functional barriers limiting diffusion. However, several studies refute the notion that this is sufficient, suggesting that phosphodiesterase-independent movement of cAMP must occur at rates slower than free diffusion. But, until now this has never been demonstrated. Using Raster Image Correlation Spectroscopy (RICS), we measured the diffusion coefficient of a fluorescently-labeled cAMP derivative (φ450-cAMP) as well as other fluorescent molecules in order to investigate the role that molecular size, cell morphology, and buffering by protein kinase A (PKA) play in restricting cAMP mobility in different cell types. Our results demonstrate that cytosolic movement of cAMP is indeed much slower than the rate of free diffusion and that interactions with PKA, especially type II PKA associated with mitochondria, play a significant role. These findings have important implications with respect to cAMP signaling in all cells.

Mechanisms Restricting Diffusion of Intracellular cAMP

PubMed Central

Agarwal, Shailesh R.; Clancy, Colleen E.; Harvey, Robert D.

2016-01-01

Although numerous receptors stimulate cAMP production in a wide array of cells, many elicit distinct, highly localized responses, implying that the subcellular distribution of cAMP is not uniform. One often used explanation is that phosphodiesterases, which breakdown cAMP, act as functional barriers limiting diffusion. However, several studies refute the notion that this is sufficient, suggesting that phosphodiesterase-independent movement of cAMP must occur at rates slower than free diffusion. But, until now this has never been demonstrated. Using Raster Image Correlation Spectroscopy (RICS), we measured the diffusion coefficient of a fluorescently-labeled cAMP derivative (φ450-cAMP) as well as other fluorescent molecules in order to investigate the role that molecular size, cell morphology, and buffering by protein kinase A (PKA) play in restricting cAMP mobility in different cell types. Our results demonstrate that cytosolic movement of cAMP is indeed much slower than the rate of free diffusion and that interactions with PKA, especially type II PKA associated with mitochondria, play a significant role. These findings have important implications with respect to cAMP signaling in all cells. PMID:26795432

CC Chemokine Receptor 5: The Interface of Host Immunity and Cancer

PubMed Central

de Oliveira, Carlos Eduardo Coral; Oda, Julie Massayo Maeda; Losi Guembarovski, Roberta; de Oliveira, Karen Brajão; Ariza, Carolina Batista; Neto, Jamil Soni; Banin Hirata, Bruna Karina; Watanabe, Maria Angelica Ehara

2014-01-01

Solid tumors are embedded in a stromal microenvironment consisting of immune cells, such as macrophages and lymphocytes, as well as nonimmune cells, such as endothelial cells and fibroblasts. Chemokines are a type of small secreted chemotactic cytokine and together with their receptors play key roles in the immune defense. Critically, they regulate cancer cellular migration and also contribute to their proliferation and survival. The CCR5 chemokine receptor is involved in leucocytes chemotaxis to sites of inflammation and plays an important role in the macrophages, T cells, and monocytes recruitment. Additionally, CCR5 may have an indirect effect on cancer progression by controlling the antitumor immune response, since it has been demonstrated that its expression could promote tumor growth and contribute to tumor metastasis, in different types of malignant tumors. Furthermore, it was demonstrated that a CCR5 antagonist may inhibit tumor growth, consisting of a possible therapeutic target. In this context, the present review focuses on the establishment of CCR5 within the interface of host immunity, tumor microenvironment, and its potential as a targeting to immunotherapy. PMID:24591756

Purification and cultivation of human pituitary growth hormone secreting cells

NASA Technical Reports Server (NTRS)

Hymer, W. C.

1984-01-01

A multiphase study was conducted to examine the properties of growth hormone cells. Topics investigated included: (1) to determine if growth hormone (GH) cells contained within the rat pituitary gland can be separated from the other hormone producing cell types by continuous flow electrophoresis (CFE); (2) to determine what role, if any, gravity plays in the electrophoretic separation of GH cells; (3) to compare in vitro GH release from rat pituitary cells previously exposed to microgravity conditions vs release from cells not exposed to microgravity; (4) to determine if the frequency of different hormone producing pituitary cell types contained in cell suspensions can be quantitated by flow cytometry; and (5) to determine if GH contained within the human post mortem pituitary gland can be purified by CFE. Specific experimental procedures and results are included.

Exosome: emerging biomarker in breast cancer

PubMed Central

Jia, Yunlu; Chen, Yongxia; Wang, Qinchuan; Jayasinghe, Ushani; Luo, Xiao; Wei, Qun; Wang, Ji; Xiong, Hanchu; Chen, Cong; Xu, Bin; Hu, Wenxian; Wang, Linbo; Zhao, Wenhe; Zhou, Jichun

2017-01-01

Exosomes are nano-sized membrane vesicles released by a variety of cell types, and are thought to play important roles in intercellular communications. In breast cancer, through horizontal transfer of various bioactive molecules, such as proteins and mRNAs, exosomes are emerging as local and systemic cell-to-cell mediators of oncogenic information and play an important role on cancer progression. This review outlines the current knowledge and concepts concerning the exosomes involvement in breast cancer pathogenesis (including tumor initiation, invasion and metastasis, angiogenesis, immune system modulation and tumor microenvironment) and cancer therapy resistance. Moreover, the potential use of exosomes as promising diagnostic and therapeutic biomarkers in breast cancer are also discussed. PMID:28402944

BAX and tumor suppressor TRP53 are important in regulating mutagenesis in spermatogenic cells in mice.

PubMed

Xu, Guogang; Vogel, Kristine S; McMahan, C Alex; Herbert, Damon C; Walter, Christi A

2010-12-01

During the first wave of spermatogenesis, and in response to ionizing radiation, elevated mutant frequencies are reduced to a low level by unidentified mechanisms. Apoptosis is occurring in the same time frame that the mutant frequency declines. We examined the role of apoptosis in regulating mutant frequency during spermatogenesis. Apoptosis and mutant frequencies were determined in spermatogenic cells obtained from Bax-null or Trp53-null mice. The results showed that spermatogenic lineage apoptosis was markedly decreased in Bax-null mice and was accompanied by a significantly increased spontaneous mutant frequency in seminiferous tubule cells compared to that of wild-type mice. Apoptosis profiles in the seminiferous tubules for Trp53-null were similar to control mice. Spontaneous mutant frequencies in pachytene spermatocytes and in round spermatids from Trp53-null mice were not significantly different from those of wild-type mice. However, epididymal spermatozoa from Trp53-null mice displayed a greater spontaneous mutant frequency compared to that from wild-type mice. A greater proportion of spontaneous transversions and a greater proportion of insertions/deletions 15 days after ionizing radiation were observed in Trp53-null mice compared to wild-type mice. Base excision repair activity in mixed germ cell nuclear extracts prepared from Trp53-null mice was significantly lower than that for wild-type controls. These data indicate that BAX-mediated apoptosis plays a significant role in regulating spontaneous mutagenesis in seminiferous tubule cells obtained from neonatal mice, whereas tumor suppressor TRP53 plays a significant role in regulating spontaneous mutagenesis between postmeiotic round spermatid and epididymal spermatozoon stages of spermiogenesis.

Dramatic performance of Clostridium thermocellum explained by its wide range of cellulase modalities.

PubMed

Xu, Qi; Resch, Michael G; Podkaminer, Kara; Yang, Shihui; Baker, John O; Donohoe, Bryon S; Wilson, Charlotte; Klingeman, Dawn M; Olson, Daniel G; Decker, Stephen R; Giannone, Richard J; Hettich, Robert L; Brown, Steven D; Lynd, Lee R; Bayer, Edward A; Himmel, Michael E; Bomble, Yannick J

2016-02-01

Clostridium thermocellum is the most efficient microorganism for solubilizing lignocellulosic biomass known to date. Its high cellulose digestion capability is attributed to efficient cellulases consisting of both a free-enzyme system and a tethered cellulosomal system wherein carbohydrate active enzymes (CAZymes) are organized by primary and secondary scaffoldin proteins to generate large protein complexes attached to the bacterial cell wall. This study demonstrates that C. thermocellum also uses a type of cellulosomal system not bound to the bacterial cell wall, called the "cell-free" cellulosomal system. The cell-free cellulosome complex can be seen as a "long range cellulosome" because it can diffuse away from the cell and degrade polysaccharide substrates remotely from the bacterial cell. The contribution of these two types of cellulosomal systems in C. thermocellum was elucidated by characterization of mutants with different combinations of scaffoldin gene deletions. The primary scaffoldin, CipA, was found to play the most important role in cellulose degradation by C. thermocellum, whereas the secondary scaffoldins have less important roles. Additionally, the distinct and efficient mode of action of the C. thermocellum exoproteome, wherein the cellulosomes splay or divide biomass particles, changes when either the primary or secondary scaffolds are removed, showing that the intact wild-type cellulosomal system is necessary for this essential mode of action. This new transcriptional and proteomic evidence shows that a functional primary scaffoldin plays a more important role compared to secondary scaffoldins in the proper regulation of CAZyme genes, cellodextrin transport, and other cellular functions.

The flavonoid quercetin induces apoptosis and inhibits JNK activation in intimal vascular smooth muscle cells

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

Perez-Vizcaino, Francisco; Bishop-Bailley, David; Lodi, Federica

Quercetin, the most abundant dietary flavonol, exerts vasodilator, anti-hypertensive, and anti-atherogenic effects and reduces the vascular remodelling associated with elevated blood pressure. Here, we have compared the effects of quercetin in intimal- and medial-type rat vascular smooth muscle cells (VSMC) in culture. After 48 h, quercetin reduced the viability of a polyclonal intimal-type cell line derived from neonatal aorta but not of a medial-type cell line derived from adult aorta. These differential effects were similar in both proliferating and quiescent VSMC. Quercetin also preferentially reduced the viability of intimal-type over medial-type VSMC in primary cultures derived from balloon-injured carotid arteries.more » The effects of quercetin on cell viability were mainly dependent upon induction of apoptosis, as demonstrated by nuclear condensation and fragmentation, and were unrelated to PPAR{gamma}, pro-oxidant effects or nitric oxide. The expression of MAPKs (ERK, p38, and JNK) and ERK phosphorylation were not different between intimal- and medial-type VSMC. p38 phosphorylation was negligible in both cell types. Medial-type showed a weak JNK phosphorylation while this was markedly increased in intimal-type cells. Quercetin reduced JNK phosphorylation but had no consistent effect on ERK phosphorylation. In conclusion, quercetin preferentially produced apoptosis in intimal-type compared to medial-type VSMC. This might play a role in the anti-atherogenic and anti-hypertensive effects of quercetin.« less

[Function and modulation of type Ⅱ innate lymphoid cells and their role in chronic upper airway inflammatory diseases].

PubMed

Liu, Y; Liu, Z

2017-02-07

Type Ⅱ innate lymphoid cells (ILC2) is a family of innate immune lymphocytes, which provide effective immune responses to cytokines. ILC2 are regulated by the nuclear transcription factor ROR alpha and GATA3, secreting cytokines IL-5 and IL-13, etc. Animal models have shown that ILC2 are involved in allergic diseases, such as asthma and atopic dermatitis, and also play a very important role in the metabolic balance. In addition, recent reports suggest that ILC2 not only play a role in the initial stages of the disease, but also can lead to chronic pathological changes in the disease, such as fibrosis, and may have an effect on acquired immunity. This paper mainly focus in the role and regulation of ILC2 cells, and review the research status of ILC2 in the field of chronic upper airway inflammatory diseases including allergic rhinitis and chronic rhinosinusitis.

Single cell analysis of voltage-gated potassium channels that determines neuronal types of rat hypothalamic paraventricular nucleus neurons.

PubMed

Lee, S K; Lee, S; Shin, S Y; Ryu, P D; Lee, S Y

2012-03-15

The hypothalamic paraventricular nucleus (PVN), a site for the integration of both the neuroendocrine and autonomic systems, has heterogeneous cell composition. These neurons are classified into type I and type II neurons based on their electrophysiological properties. In the present study, we investigated the molecular identification of voltage-gated K+ (Kv) channels, which determines a distinctive characteristic of type I PVN neurons, by means of single-cell reverse transcription-polymerase chain reaction (RT-PCR) along with slice patch clamp recordings. In order to determine the mRNA expression profiles, firstly, the PVN neurons of male rats were classified into type I and type II neurons, and then, single-cell RT-PCR and single-cell real-time RT-PCR analysis were performed using the identical cell. The single-cell RT-PCR analysis revealed that Kv1.2, Kv1.3, Kv1.4, Kv4.1, Kv4.2, and Kv4.3 were expressed both in type I and in type II neurons, and several Kv channels were co-expressed in a single PVN neuron. However, we found that the expression densities of Kv4.2 and Kv4.3 were significantly higher in type I neurons than in type II neurons. Taken together, several Kv channels encoding A-type K+ currents are present both in type I and in type II neurons, and among those, Kv4.2 and Kv4.3 are the major Kv subunits responsible for determining the distinct electrophysiological properties. Thus these 2 Kv subunits may play important roles in determining PVN cell types and regulating PVN neuronal excitability. This study further provides key molecular mechanisms for differentiating type I and type II PVN neurons. Copyright © 2012 IBRO. Published by Elsevier Ltd. All rights reserved.

The C-terminal hypervariable domain targets Aradopsis ROP9 to the invaginated pollen tube plasma membrane

USDA-ARS?s Scientific Manuscript database

Rop9 is a small GTPase of the Type II class, whereas the often studied type I Rops play roles during pollen tube growth. In pollen, Rop9 is located at the invaginated plasma membrane that surrounds the sperm cells, whereas type I Rops are located at the apical membrane of the pollen tube. The C-ter...

Development of A-type allatostatin immunoreactivity in antennal lobe neurons of the sphinx moth Manduca sexta.

PubMed

Utz, Sandra; Schachtner, Joachim

2005-04-01

The antennal lobe (AL) of the sphinx moth Manduca sexta is a well-established model system for studying mechanisms of neuronal development. To understand whether neuropeptides are suited to playing a role during AL development, we have studied the cellular localization and temporal expression pattern of neuropeptides of the A-type allatostatin family. Based on morphology and developmental appearance, we distinguished four types of AST-A-immunoreactive cell types. The majority of the cells were local interneurons of the AL (type Ia) which acquired AST-A immunostaining in a complex pattern consisting of three rising (RI-RIII) and two declining phases (DI, DII). Type Ib neurons consisted of two local neurons with large cell bodies not appearing before 7/8 days after pupal ecdysis (P7/P8). Types II and III neurons accounted for single centrifugal neurons, with type II neurons present in the larva and disappearing in the early pupa. The type III neuron did not appear before P7/P8. RI and RII coincided with the rises of the ecdysteroid hemolymph titer. Artificially shifting the pupal 20-hydroxyecdysone (20E) peak to an earlier developmental time point resulted in the precocious appearance of AST-A immunostaining in types Ia, Ib, and III neurons. This result supports the hypothesis that the pupal rise in 20E plays a role in AST-A expression during AL development. Because of their early appearance in newly forming glomeruli, AST-A-immunoreactive fibers could be involved in glomerulus formation. Diffuse AST-A labeling during early AL development is discussed as a possible signal providing information for ingrowing olfactory receptor neurons.

Controversial role of mast cells in skin cancers.

PubMed

Varricchi, Gilda; Galdiero, Maria R; Marone, Giancarlo; Granata, Francescopaolo; Borriello, Francesco; Marone, Gianni

2017-01-01

Cancer development is a multistep process characterized by genetic and epigenetic alterations during tumor initiation and progression. The stromal microenvironment can promote tumor development. Mast cells, widely distributed throughout all tissues, are a stromal component of many solid and haematologic tumors. Mast cells can be found in human and mouse models of skin cancers such as melanoma, basal and squamous cell carcinomas, primary cutaneous lymphomas, haemangiomas and Merkel cell carcinoma. However, human and animal studies addressing potential functions of mast cells and their mediators in skin cancers have provided conflicting results. In several studies, mast cells play a pro-tumorigenic role, whereas in others, they play an anti-tumorigenic role. Other studies have failed to demonstrate a clear role for tumor-associated mast cells. Many unanswered questions need to be addressed before we understand whether tumor-associated mast cells are adversaries, allies or simply innocent bystanders in different types and subtypes of skin cancers. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Dectin-1 plays an important role in host defense against systemic Candida glabrata infection.

PubMed

Chen, Si Min; Shen, Hui; Zhang, Teng; Huang, Xin; Liu, Xiao Qi; Guo, Shi Yu; Zhao, Jing Jun; Wang, Chun Fang; Yan, Lan; Xu, Guo Tong; Jiang, Yuan Ying; An, Mao Mao

2017-11-17

Candida glabrata is the second most common pathogen of severe candidiasis in immunocompromised hosts, following C. albicans. Although C. glabrata and C. albicans belong to the same genus, they are phylogenetically distinct. C-type lectin receptors (CLRs), acting as pattern-recognition receptors (PRRs), play critical roles in host defense against C. albicans infections. However, our understanding of the specific roles of CLRs in host defense against C. glabrata is limited. Here, we explored the potential roles of the C-type lectins Dectin-1 and Dectin-2 in host defense against C. glabrata. We found that both Dectin-1-deficient mice (Dectin-1 -/- ) and Dectin-2-deficient mice (Dectin-2 -/- ) are more susceptible to C. glabrata infection. Dectin-1confers host higher sensitivity for sensing C. glabrata infections, while the effect of Dectin-2 in the host defense against C. glabrata is infection dose dependent. Dectin-1 is required for host myeloid cells recognition, killing of C. glabrata, and development of subsequent Th1 and Th17 cell-mediated adaptive immune response. Significantly impaired inflammatory responses such as inflammatory cells recruitment and cytokines release that were induced by C. glabrata were manifested in Dectin-1-deficient mice. Together, our study demonstrates that Dectin-1 plays an important role in host defense against systemic Candida glabrata infections, indicating a previous unknown control mechanism for this particular type of infection in host. Our study, therefore, provides new insights into the host defense against C. glabrata.

BIOLOGICAL AND BIOPHYSICAL PROPERTIES OF VASCULAR CONNEXIN CHANNELS

PubMed Central

Johnstone, Scott; Isakson, Brant; Locke, Darren

2010-01-01

Intercellular channels formed by connexin proteins play a pivotal role in the direct movement of ions and larger cytoplasmic solutes between vascular endothelial cells, between vascular smooth muscle cells, and between endothelial and smooth muscle cells. Multiple genetic and epigenetic factors modulate connexin expression levels and/or channel function, including cell type-independent and cell type-specific transcription factors, posttranslational modification and localized membrane targeting. Additionally, differences in protein-protein interactions, including those between connexins, significantly contribute to both vascular homeostasis and disease progression. The biophysical properties of the connexin channels identified in the vasculature, those formed by Cx37, Cx40, Cx43 and/or Cx45 proteins, are discussed in this review in the physiological and pathophysiological context of vessel function. PMID:19815177

Birthdating Studies Reshape Models for Pituitary Gland Cell Specification

PubMed Central

Davis, Shannon W.; Mortensen, Amanda H.; Camper, Sally A.

2011-01-01

The intermediate and anterior lobes of the pituitary gland are derived from an invagination of oral ectoderm that forms Rathke’s pouch. During gestation proliferating cells are enriched around the pouch lumen, and they appear to delaminate as they exit the cell cycle and differentiate. During late mouse gestation and the post-natal period, anterior lobe progenitors re-enter the cell cycle and expand the populations of specialized, hormone-producing cells. At birth, all cell types are present, and their localization appears stratified based on cell type. We conducted a birth dating study of Rathke’s pouch derivatives to determine whether the location of specialized cells at birth is correlated with the timing of cell cycle exit. We find that all of the anterior lobe cell types initiate differentiation concurrently with a peak between e11.5 and e13.5. Differentiation of intermediate lobe melanotropes is delayed relative to anterior lobe cell types. We discovered that specialized cell types are not grouped together based on birth date and are dispersed throughout the anterior lobe. Thus, the apparent stratification of specialized cells at birth is not correlated with cell cycle exit. Thus, the currently popular model of cell specification, dependent upon timing of extrinsic, directional gradients of signaling molecules, needs revision. We propose that signals intrinsic to Rathke’s pouch are necessary for cell specification between e11.5 and e13.5 and that cell-cell communication likely plays an important role in regulating this process. PMID:21262217

Birthdating studies reshape models for pituitary gland cell specification.

PubMed

Davis, Shannon W; Mortensen, Amanda H; Camper, Sally A

2011-04-15

The intermediate and anterior lobes of the pituitary gland are derived from an invagination of oral ectoderm that forms Rathke's pouch. During gestation proliferating cells are enriched around the pouch lumen, and they appear to delaminate as they exit the cell cycle and differentiate. During late mouse gestation and the postnatal period, anterior lobe progenitors re-enter the cell cycle and expand the populations of specialized, hormone-producing cells. At birth, all cell types are present, and their localization appears stratified based on cell type. We conducted a birth dating study of Rathke's pouch derivatives to determine whether the location of specialized cells at birth is correlated with the timing of cell cycle exit. We find that all of the anterior lobe cell types initiate differentiation concurrently with a peak between e11.5 and e13.5. Differentiation of intermediate lobe melanotropes is delayed relative to anterior lobe cell types. We discovered that specialized cell types are not grouped together based on birth date and are dispersed throughout the anterior lobe. Thus, the apparent stratification of specialized cells at birth is not correlated with cell cycle exit. Thus, the currently popular model of cell specification, dependent upon timing of extrinsic, directional gradients of signaling molecules, needs revision. We propose that signals intrinsic to Rathke's pouch are necessary for cell specification between e11.5 and e13.5 and that cell-cell communication likely plays an important role in regulating this process. Copyright © 2011 Elsevier Inc. All rights reserved.

Lethal cutaneous disease in transgenic mice conditionally expressing type I human T cell leukemia virus Tax.

PubMed

Kwon, Hakju; Ogle, Louise; Benitez, Bobby; Bohuslav, Jan; Montano, Mauricio; Felsher, Dean W; Greene, Warner C

2005-10-21

Type I human T cell leukemia virus (HTLV-I) is etiologically linked with adult T cell leukemia, an aggressive and usually fatal expansion of activated CD4+ T lymphocytes that frequently traffic to skin. T cell transformation induced by HTLV-I involves the action of the 40-kDa viral Tax transactivator protein. Tax both stimulates the HTLV-I long terminal repeat and deregulates the expression of select cellular genes by altering the activity of specific host transcription factors, including cyclic AMP-responsive element-binding protein (CREB)/activating transcription factor, NF-kappaB/Rel, and serum response factor. To study initiating events involved in HTLV-I Tax-induced T cell transformation, we generated "Tet-off" transgenic mice conditionally expressing in a lymphocyte-restricted manner (EmuSR alpha promoter-enhancer) either wild-type Tax or mutant forms of Tax that selectively compromise the NF-kappaB (M22) or CREB/activating transcription factor (M47) activation pathways. Wild-type Tax and M47 Tax-expressing mice, but not M22-Tax expressing mice, developed progressive alopecia, hyperkeratosis, and skin lesions containing profuse activated CD4 T cell infiltrates with evidence of deregulated inflammatory cytokine production. In addition, these animals displayed systemic lymphadenopathy and splenomegaly. These findings suggest that Tax-mediated activation of NF-kappaB plays a key role in the development of this aggressive skin disease that shares several features in common with the skin disease occurring during the preleukemic stage in HTLV-I-infected patients. Of note, this skin disease completely resolved when Tax transgene expression was suppressed by administration of doxycycline, emphasizing the key role played by this viral oncoprotein in the observed pathology.

Searching the literature for proteins facilitates the identification of biological processes, if advanced methods of analysis are linked: a case study on microgravity-caused changes in cells.

PubMed

Bauer, Johann; Bussen, Markus; Wise, Petra; Wehland, Markus; Schneider, Sabine; Grimm, Daniela

2016-07-01

More than one hundred reports were published about the characterization of cells from malignant and healthy tissues, as well as of endothelial cells and stem cells exposed to microgravity conditions. We retrieved publications about microgravity related studies on each type of cells, extracted the proteins mentioned therein and analyzed them aiming to identify biological processes affected by microgravity culture conditions. The analysis revealed 66 different biological processes, 19 of them were always detected when papers about the four types of cells were analyzed. Since a response to the removal of gravity is common to the different cell types, some of the 19 biological processes could play a role in cellular adaption to microgravity. Applying computer programs, to extract and analyze proteins and genes mentioned in publications becomes essential for scientists interested to get an overview of the rapidly growing fields of gravitational biology and space medicine.

Ultrastructural and functional characterization of circulating hemocytes from Galleria mellonella larva: Cell types and their role in the innate immunity.

PubMed

Wu, Gongqing; Liu, Yi; Ding, Ying; Yi, Yunhong

2016-08-01

Galleria mellonella larvae have been widely used as a model to study the virulence of various human pathogens. Hemocytes play important roles in the innate immune response of G. mellonella. In this study, the hemocytes of G. mellonella larvae were analyzed by transmission electron microscope, light microscope, and cytochemistry. The cytological and morphological analyses revealed four types of hemocytes; Plasmatocytes, granular cells, spherule cells and oenocytoids. Differential hemocyte counts showed that under our conditions plasmatocytes and granular cells were the most abundant circulating cell types in the hemolymph. We also investigated the role of different types of hemocytes in the cellular and humoral immune defenses. The in-vivo experiment showed that plasmatocytes, granular cells and oenocytoids phagocytized FITC-labelled Escherichia coli bacteria in larvae of G. mellonella, whereas the granular cells exhibited the strongest phagocytic ability against these microbial cells. After incubation with L-DOPA, plasmatocytes, granular cells and oenocytoids are stained brown, indicating the presence of phenoloxidase activity. These results shed new light on our understanding of the immune function of G. mellonella hemocytes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Choline acetyltransferase immunoreactivity in the human vestibular end-organs.

PubMed

Ishiyama, A; Lopez, I; Wackym, P A

1994-10-01

Acetylcholine (ACh) is believed to play a major role in the efferent vestibular system in several animal models, however no information regarding the role of ACh in the human efferent vestibular system has been published. Post-embedding immunohistochemistry in a hydrophilic resin was used to investigate the choline acetyltransferase immunoreactivity (ChATi) and acetylcholinesterase (AChE) histochemistry in human vestibular end-organs. ChATi and AChE activity was found in numerous bouton-type terminals at the basal area of the vestibular hair cells. These terminals were found to contact type II vestibular hair cells and the afferent chalices surrounding type I hair cells. This study provides the first evidence that the human efferent vestibular axons and terminals are cholinergic.

Tim18, a component of the mitochondrial translocator, mediates yeast cell death induced by arsenic.

PubMed

Du, Li; Yu, Yong; Li, Zidong; Chen, Jingsi; Liu, Yan; Xia, Yongjing; Liu, Xiangjun

2007-08-01

Evidence is presented that Tim18, a mitochondria translocase, plays a role in the previously described apoptosis induced by arsenite in Saccharomyces cerevisiae. Tim18 deletion mutant exhibited resistance to arsenite. After arsenite treatment, both the wild type and Tim18-deficient cells showed reactive oxygen species (ROS) production. Arsenite induced the higher expression of tim18 in wild type yeast cells. We found that the tim18 deletion mutant also exhibited resistance to other apoptotic stresses such as acetic acid, H2O2, and hyperosmotic stress. These results suggest that Tim18 is important for yeast cell death induced by arsenic, and it may act downstream of ROS production.

Molecular characterization of chronic-type adult T-cell leukemia/lymphoma.

PubMed

Yoshida, Noriaki; Karube, Kennosuke; Utsunomiya, Atae; Tsukasaki, Kunihiro; Imaizumi, Yoshitaka; Taira, Naoya; Uike, Naokuni; Umino, Akira; Arita, Kotaro; Suguro, Miyuki; Tsuzuki, Shinobu; Kinoshita, Tomohiro; Ohshima, Koichi; Seto, Masao

2014-11-01

Adult T-cell leukemia/lymphoma (ATL) is a human T-cell leukemia virus type-1-induced neoplasm with four clinical subtypes: acute, lymphoma, chronic, and smoldering. Although the chronic type is regarded as indolent ATL, about half of the cases progress to acute-type ATL. The molecular pathogenesis of acute transformation in chronic-type ATL is only partially understood. In an effort to determine the molecular pathogeneses of ATL, and especially the molecular mechanism of acute transformation, oligo-array comparative genomic hybridization and comprehensive gene expression profiling were applied to 27 and 35 cases of chronic and acute type ATL, respectively. The genomic profile of the chronic type was nearly identical to that of acute-type ATL, although more genomic alterations characteristic of acute-type ATL were observed. Among the genomic alterations frequently observed in acute-type ATL, the loss of CDKN2A, which is involved in cell-cycle deregulation, was especially characteristic of acute-type ATL compared with chronic-type ATL. Furthermore, we found that genomic alteration of CD58, which is implicated in escape from the immunosurveillance mechanism, is more frequently observed in acute-type ATL than in the chronic-type. Interestingly, the chronic-type cases with cell-cycle deregulation and disruption of immunosurveillance mechanism were associated with earlier progression to acute-type ATL. These findings suggested that cell-cycle deregulation and the immune escape mechanism play important roles in acute transformation of the chronic type and indicated that these alterations are good predictive markers for chronic-type ATL. ©2014 American Association for Cancer Research.

Dnmt1 activity is dispensable in δ-cells but is essential for α-cell homeostasis.

PubMed

Damond, Nicolas; Thorel, Fabrizio; Kim, Seung K; Herrera, Pedro L

2017-07-01

In addition to β-cells, pancreatic islets contain α- and δ-cells, which respectively produce glucagon and somatostatin. The reprogramming of these two endocrine cell types into insulin producers, as observed after a massive β-cell ablation in mice, may help restoring a functional β-cell mass in type 1 diabetes. Yet, the spontaneous α-to-β and δ-to-β conversion processes are relatively inefficient in adult animals and the underlying epigenetic mechanisms remain unclear. Several studies indicate that the conserved chromatin modifiers DNA methyltransferase 1 (Dnmt1) and Enhancer of zeste homolog 2 (Ezh2) are important for pancreas development and restrict islet cell plasticity. Here, to investigate the role of these two enzymes in α- and δ-cell development and fate maintenance, we genetically inactivated them in each of these two cell types. We found that loss of Dnmt1 does not enhance the conversion of α- or δ-cells toward a β-like fate. In addition, while Dnmt1 was dispensable for the development of these two cell types, we noticed a gradual loss of α-, but not δ-cells in adult mice. Finally, we found that Ezh2 inactivation does not enhance α-cell plasticity, and, contrary to what is observed in β-cells, does not impair α-cell proliferation. Our results indicate that both Dnmt1 and Ezh2 play distinct roles in the different islet cell types. Copyright © 2017 Elsevier Ltd. All rights reserved.

Matrix metalloproteinases and epidermal wound repair.

PubMed

Martins, Vera L; Caley, Matthew; O'Toole, Edel A

2013-02-01

Epidermal wound healing is a complex and highly coordinated process where several different cell types and molecules, such as growth factors and extracellular matrix (ECM) components, play an important role. Among the many proteins that are essential for the restoration of tissue integrity is the metalloproteinase (MMP) family. MMPs can act on ECM and non-ECM components affecting degradation and modulation of the ECM, growth-factor activation and cell-cell and cell-matrix signalling. MMPs are secreted by different cell types such as keratinocytes, fibroblasts and inflammatory cells at different stages and locations during wound healing, thereby regulating this process in a very coordinated and controlled way. In this article, we review the role of MMPs and their inhibitors (TIMPs), as well as the disintegrin and metalloproteinase with the thrombospondin motifs (ADAMs) family, in epithelial wound repair.

The T-cell-specific adapter protein family: TSAd, ALX, and SH2D4A/SH2D4B.

PubMed

Lapinski, Philip E; Oliver, Jennifer A; Bodie, Jennifer N; Marti, Francesc; King, Philip D

2009-11-01

Adapter proteins play key roles in intracellular signal transduction through complex formation with catalytically active signaling molecules. In T lymphocytes, the role of several different types of adapter proteins in T-cell antigen receptor signal transduction is well established. An exception to this is the family of T-cell-specific adapter (TSAd) proteins comprising of TSAd, adapter protein of unknown function (ALX), SH2D4A, and SH2D4B. Only recently has the function of these adapters in T-cell signal transduction been explored. Here, we discuss advances in our understanding of the role of this family of adapter proteins in T cells. Their function as regulators of signal transduction in other cell types is also discussed.

Smooth muscle tension induces invasive remodeling of the zebrafish intestine.

PubMed

Seiler, Christoph; Davuluri, Gangarao; Abrams, Joshua; Byfield, Fitzroy J; Janmey, Paul A; Pack, Michael

2012-01-01

The signals that initiate cell invasion are not well understood, but there is increasing evidence that extracellular physical signals play an important role. Here we show that epithelial cell invasion in the intestine of zebrafish meltdown (mlt) mutants arises in response to unregulated contractile tone in the surrounding smooth muscle cell layer. Physical signaling in mlt drives formation of membrane protrusions within the epithelium that resemble invadopodia, matrix-degrading protrusions present in invasive cancer cells. Knockdown of Tks5, a Src substrate that is required for invadopodia formation in mammalian cells blocked formation of the protrusions and rescued invasion in mlt. Activation of Src-signaling induced invadopodia-like protrusions in wild type epithelial cells, however the cells did not migrate into the tissue stroma, thus indicating that the protrusions were required but not sufficient for invasion in this in vivo model. Transcriptional profiling experiments showed that genes responsive to reactive oxygen species (ROS) were upregulated in mlt larvae. ROS generators induced invadopodia-like protrusions and invasion in heterozygous mlt larvae but had no effect in wild type larvae. Co-activation of oncogenic Ras and Wnt signaling enhanced the responsiveness of mlt heterozygotes to the ROS generators. These findings present the first direct evidence that invadopodia play a role in tissue cell invasion in vivo. In addition, they identify an inducible physical signaling pathway sensitive to redox and oncogenic signaling that can drive this process.

Smooth Muscle Tension Induces Invasive Remodeling of the Zebrafish Intestine

PubMed Central

Seiler, Christoph; Davuluri, Gangarao; Abrams, Joshua; Byfield, Fitzroy J.; Janmey, Paul A.; Pack, Michael

2012-01-01

The signals that initiate cell invasion are not well understood, but there is increasing evidence that extracellular physical signals play an important role. Here we show that epithelial cell invasion in the intestine of zebrafish meltdown (mlt) mutants arises in response to unregulated contractile tone in the surrounding smooth muscle cell layer. Physical signaling in mlt drives formation of membrane protrusions within the epithelium that resemble invadopodia, matrix-degrading protrusions present in invasive cancer cells. Knockdown of Tks5, a Src substrate that is required for invadopodia formation in mammalian cells blocked formation of the protrusions and rescued invasion in mlt. Activation of Src-signaling induced invadopodia-like protrusions in wild type epithelial cells, however the cells did not migrate into the tissue stroma, thus indicating that the protrusions were required but not sufficient for invasion in this in vivo model. Transcriptional profiling experiments showed that genes responsive to reactive oxygen species (ROS) were upregulated in mlt larvae. ROS generators induced invadopodia-like protrusions and invasion in heterozygous mlt larvae but had no effect in wild type larvae. Co-activation of oncogenic Ras and Wnt signaling enhanced the responsiveness of mlt heterozygotes to the ROS generators. These findings present the first direct evidence that invadopodia play a role in tissue cell invasion in vivo. In addition, they identify an inducible physical signaling pathway sensitive to redox and oncogenic signaling that can drive this process. PMID:22973180

Type I insulin-like growth factor receptor signaling in hematological malignancies

PubMed Central

Vishwamitra, Deeksha; George, Suraj Konnath; Shi, Ping; Kaseb, Ahmed O.; Amin, Hesham M.

2017-01-01

The insulin-like growth factor (IGF) signaling system plays key roles in the establishment and progression of different types of cancer. In agreement with this idea, substantial evidence has shown that the type I IGF receptor (IGF-IR) and its primary ligand IGF-I are important for maintaining the survival of malignant cells of hematopoietic origin. In this review, we discuss current understanding of the role of IGF-IR signaling in cancer with a focus on the hematological neoplasms. We also address the emergence of IGF-IR as a potential therapeutic target for the treatment of different types of cancer including plasma cell myeloma, leukemia, and lymphoma. PMID:27661006

Homogeneity of lithium distribution in cylinder-type Li-ion batteries

PubMed Central

Senyshyn, A.; Mühlbauer, M. J.; Dolotko, O.; Hofmann, M.; Ehrenberg, H.

2015-01-01

Spatially-resolved neutron powder diffraction with a gauge volume of 2 × 2 × 20 mm3 has been applied as an in situ method to probe the lithium concentration in the graphite anode of different Li-ion cells of 18650-type in charged state. Structural studies performed in combination with electrochemical measurements and X-ray computed tomography under real cell operating conditions unambiguously revealed non-homogeneity of the lithium distribution in the graphite anode. Deviations from a homogeneous behaviour have been found in both radial and axial directions of 18650-type cells and were discussed in the frame of cell geometry and electrical connection of electrodes, which might play a crucial role in the homogeneity of the lithium distribution in the active materials within each electrode. PMID:26681110

Antiviral Activity of Lambda Interferon in Chickens

PubMed Central

Reuter, Antje; Soubies, Sebastien; Härtle, Sonja; Schusser, Benjamin; Kaspers, Bernd

2014-01-01

Interferons (IFNs) are essential components of the antiviral defense system of vertebrates. In mammals, functional receptors for type III IFN (lambda interferon [IFN-λ]) are found mainly on epithelial cells, and IFN-λ was demonstrated to play a crucial role in limiting viral infections of mucosal surfaces. To determine whether IFN-λ plays a similar role in birds, we produced recombinant chicken IFN-λ (chIFN-λ) and we used the replication-competent retroviral RCAS vector system to generate mosaic-transgenic chicken embryos that constitutively express chIFN-λ. We could demonstrate that chIFN-λ markedly inhibited replication of various virus strains, including highly pathogenic influenza A viruses, in ovo and in vivo, as well as in epithelium-rich tissue and cell culture systems. In contrast, chicken fibroblasts responded poorly to chIFN-λ. When applied in vivo to 3-week-old chickens, recombinant chIFN-λ strongly induced the IFN-responsive Mx gene in epithelium-rich organs, such as lungs, tracheas, and intestinal tracts. Correspondingly, these organs were found to express high transcript levels of the putative chIFN-λ receptor alpha chain (chIL28RA) gene. Transfection of chicken fibroblasts with a chIL28RA expression construct rendered these cells responsive to chIFN-λ treatment, indicating that receptor expression determines cell type specificity of IFN-λ action in chickens. Surprisingly, mosaic-transgenic chickens perished soon after hatching, demonstrating a detrimental effect of constitutive chIFN-λ expression. Our data highlight fundamental similarities between the IFN-λ systems of mammals and birds and suggest that type III IFN might play a role in defending mucosal surfaces against viral intruders in most if not all vertebrates. PMID:24371053

A novel subset of helper T cells promotes immune responses by secreting GM-CSF

PubMed Central

Zhang, J; Roberts, A I; Liu, C; Ren, G; Xu, G; Zhang, L; Devadas, S; Shi, Yufang

2013-01-01

Helper T cells are crucial for maintaining proper immune responses. Yet, they have an undefined relationship with one of the most potent immune stimulatory cytokines, granulocyte macrophage-colony-stimulating factor (GM-CSF). By depleting major cytokines during the differentiation of CD4+ T cells in vitro, we derived cells that were found to produce large amounts of GM-CSF, but little of the cytokines produced by other helper T subsets. By their secretion of GM-CSF, this novel subset of helper T cells (which we have termed ThGM cells) promoted the production of cytokines by other T-cell subtypes, including type 1 helper T cell (Th1), type 2 helper T cell (Th2), type 1 cytotoxic T cell (Tc1), type 2 cytotoxic T cell (Tc2), and naive T cells, as evidenced by the fact that antibody neutralization of GM-CSF abolished this effect. ThGM cells were found to be highly prone to activation-induced cell death (AICD). Inhibitors of TRAIL or granzymes could not block AICD in ThGM cells, whereas inhibition of FasL/Fas interaction partially rescued ThGM cells from AICD. Thus, ThGM cells are a novel subpopulation of T helper cells that produce abundant GM-CSF, exhibit exquisite susceptibility to apoptosis, and therefore play a pivotal role in the regulation of the early stages of immune responses. PMID:24076588

INFLUENZA-INDUCED UP-REGULATION OF TLR3 IN RESPIRATORY EPITHELIAL CELLS MAY OCCUR THROUGH A POSITIVE FEEDBACK LOOP INVOLVING TYPE I INTERFERON

EPA Science Inventory

Toll-like receptor 3 (TLR3) plays an important role in the host defense responses against viral infections, including Influenza virus infections. Based on our previous observations showing that Influenza infection of respiratory epithelial cells results in an up-regulation of Tol...

Comprehensive Identification of Long Non-coding RNAs in Purified Cell Types from the Brain Reveals Functional LncRNA in OPC Fate Determination

PubMed Central

Dong, Xiaomin; Chen, Kenian; Cuevas-Diaz Duran, Raquel; You, Yanan; Sloan, Steven A.; Zhang, Ye; Zong, Shan; Cao, Qilin; Barres, Ben A.; Wu, Jia Qian

2015-01-01

Long non-coding RNAs (lncRNAs) (> 200 bp) play crucial roles in transcriptional regulation during numerous biological processes. However, it is challenging to comprehensively identify lncRNAs, because they are often expressed at low levels and with more cell-type specificity than are protein-coding genes. In the present study, we performed ab initio transcriptome reconstruction using eight purified cell populations from mouse cortex and detected more than 5000 lncRNAs. Predicting the functions of lncRNAs using cell-type specific data revealed their potential functional roles in Central Nervous System (CNS) development. We performed motif searches in ENCODE DNase I digital footprint data and Mouse ENCODE promoters to infer transcription factor (TF) occupancy. By integrating TF binding and cell-type specific transcriptomic data, we constructed a novel framework that is useful for systematically identifying lncRNAs that are potentially essential for brain cell fate determination. Based on this integrative analysis, we identified lncRNAs that are regulated during Oligodendrocyte Precursor Cell (OPC) differentiation from Neural Stem Cells (NSCs) and that are likely to be involved in oligodendrogenesis. The top candidate, lnc-OPC, shows highly specific expression in OPCs and remarkable sequence conservation among placental mammals. Interestingly, lnc-OPC is significantly up-regulated in glial progenitors from experimental autoimmune encephalomyelitis (EAE) mouse models compared to wild-type mice. OLIG2-binding sites in the upstream regulatory region of lnc-OPC were identified by ChIP (chromatin immunoprecipitation)-Sequencing and validated by luciferase assays. Loss-of-function experiments confirmed that lnc-OPC plays a functional role in OPC genesis. Overall, our results substantiated the role of lncRNA in OPC fate determination and provided an unprecedented data source for future functional investigations in CNS cell types. We present our datasets and analysis results via the interactive genome browser at our laboratory website that is freely accessible to the research community. This is the first lncRNA expression database of collective populations of glia, vascular cells, and neurons. We anticipate that these studies will advance the knowledge of this major class of non-coding genes and their potential roles in neurological development and diseases. PMID:26683846

Highly conserved type 1 pili promote enterotoxigenic E. coli pathogen-host interactions

PubMed Central

Rashu, Rasheduzzaman; Begum, Yasmin Ara; Ciorba, Matthew A.; Hultgren, Scott J.; Qadri, Firdausi

2017-01-01

Enterotoxigenic Escherichia coli (ETEC), defined by their elaboration of heat-labile (LT) and/or heat-stable (ST) enterotoxins, are a common cause of diarrheal illness in developing countries. Efficient delivery of these toxins requires ETEC to engage target host enterocytes. This engagement is accomplished using a variety of pathovar-specific and conserved E. coli adhesin molecules as well as plasmid encoded colonization factors. Some of these adhesins undergo significant transcriptional modulation as ETEC encounter intestinal epithelia, perhaps suggesting that they cooperatively facilitate interaction with the host. Among genes significantly upregulated on cell contact are those encoding type 1 pili. We therefore investigated the role played by these pili in facilitating ETEC adhesion, and toxin delivery to model intestinal epithelia. We demonstrate that type 1 pili, encoded in the E. coli core genome, play an essential role in ETEC virulence, acting in concert with plasmid-encoded pathovar specific colonization factor (CF) fimbriae to promote optimal bacterial adhesion to cultured intestinal epithelium (CIE) and to epithelial monolayers differentiated from human small intestinal stem cells. Type 1 pili are tipped with the FimH adhesin which recognizes mannose with stereochemical specificity. Thus, enhanced production of highly mannosylated proteins on intestinal epithelia promoted FimH-mediated ETEC adhesion, while conversely, interruption of FimH lectin-epithelial interactions with soluble mannose, anti-FimH antibodies or mutagenesis of fimH effectively blocked ETEC adhesion. Moreover, fimH mutants were significantly impaired in delivery of both heat-stable and heat-labile toxins to the target epithelial cells in vitro, and these mutants were substantially less virulent in rabbit ileal loop assays, a classical model of ETEC pathogenesis. Collectively, our data suggest that these highly conserved pili play an essential role in virulence of these diverse pathogens. PMID:28531220

Systematic pan-cancer analysis reveals immune cell interactions in the tumor microenvironment

PubMed Central

Varn, Frederick S.; Wang, Yue; Mullins, David W.; Fiering, Steven; Cheng, Chao

2017-01-01

With the recent advent of immunotherapy, there is a critical need to understand immune cell interactions in the tumor microenvironment in both pan-cancer and tissue-specific contexts. Multi-dimensional datasets have enabled systematic approaches to dissect these interactions in large numbers of patients, furthering our understanding of the patient immune response to solid tumors. Using an integrated approach, we inferred the infiltration levels of distinct immune cell subsets in 23 tumor types from The Cancer Genome Atlas. From these quantities, we constructed a co-infiltration network, revealing interactions between cytolytic cells and myeloid cells in the tumor microenvironment. By integrating patient mutation data, we found that while mutation burden was associated with immune infiltration differences between distinct tumor types, additional factors likely explained differences between tumors originating from the same tissue. We concluded this analysis by examining the prognostic value of individual immune cell subsets as well as how co-infiltration of functionally discordant cell types associated with patient survival. In multiple tumor types, we found that the protective effect of CD8+ T cell infiltration was heavily modulated by co-infiltration of macrophages and other myeloid cell types, suggesting the involvement of myeloid-derived suppressor cells in tumor development. Our findings illustrate complex interactions between different immune cell types in the tumor microenvironment and indicate these interactions play meaningful roles in patient survival. These results demonstrate the importance of personalized immune response profiles when studying the factors underlying tumor immunogenicity and immunotherapy response. PMID:28126714

Human T-lymphotropic virus type 1-infected cells secrete exosomes that contain Tax protein.

PubMed

Jaworski, Elizabeth; Narayanan, Aarthi; Van Duyne, Rachel; Shabbeer-Meyering, Shabana; Iordanskiy, Sergey; Saifuddin, Mohammed; Das, Ravi; Afonso, Philippe V; Sampey, Gavin C; Chung, Myung; Popratiloff, Anastas; Shrestha, Bindesh; Sehgal, Mohit; Jain, Pooja; Vertes, Akos; Mahieux, Renaud; Kashanchi, Fatah

2014-08-08

Human T-lymphotropic virus type 1 (HTLV-1) is the causative agent of adult T-cell leukemia and HTLV-1-associated myelopathy/tropical spastic paraparesis. The HTLV-1 transactivator protein Tax controls many critical cellular pathways, including host cell DNA damage response mechanisms, cell cycle progression, and apoptosis. Extracellular vesicles called exosomes play critical roles during pathogenic viral infections as delivery vehicles for host and viral components, including proteins, mRNA, and microRNA. We hypothesized that exosomes derived from HTLV-1-infected cells contain unique host and viral proteins that may contribute to HTLV-1-induced pathogenesis. We found exosomes derived from infected cells to contain Tax protein and proinflammatory mediators as well as viral mRNA transcripts, including Tax, HBZ, and Env. Furthermore, we observed that exosomes released from HTLV-1-infected Tax-expressing cells contributed to enhanced survival of exosome-recipient cells when treated with Fas antibody. This survival was cFLIP-dependent, with Tax showing induction of NF-κB in exosome-recipient cells. Finally, IL-2-dependent CTLL-2 cells that received Tax-containing exosomes were protected from apoptosis through activation of AKT. Similar experiments with primary cultures showed protection and survival of peripheral blood mononuclear cells even in the absence of phytohemagglutinin/IL-2. Surviving cells contained more phosphorylated Rb, consistent with the role of Tax in regulation of the cell cycle. Collectively, these results suggest that exosomes may play an important role in extracellular delivery of functional HTLV-1 proteins and mRNA to recipient cells. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Human T-lymphotropic Virus Type 1-infected Cells Secrete Exosomes That Contain Tax Protein*

PubMed Central

Jaworski, Elizabeth; Narayanan, Aarthi; Van Duyne, Rachel; Shabbeer-Meyering, Shabana; Iordanskiy, Sergey; Saifuddin, Mohammed; Das, Ravi; Afonso, Philippe V.; Sampey, Gavin C.; Chung, Myung; Popratiloff, Anastas; Shrestha, Bindesh; Sehgal, Mohit; Jain, Pooja; Vertes, Akos; Mahieux, Renaud; Kashanchi, Fatah

2014-01-01

Human T-lymphotropic virus type 1 (HTLV-1) is the causative agent of adult T-cell leukemia and HTLV-1-associated myelopathy/tropical spastic paraparesis. The HTLV-1 transactivator protein Tax controls many critical cellular pathways, including host cell DNA damage response mechanisms, cell cycle progression, and apoptosis. Extracellular vesicles called exosomes play critical roles during pathogenic viral infections as delivery vehicles for host and viral components, including proteins, mRNA, and microRNA. We hypothesized that exosomes derived from HTLV-1-infected cells contain unique host and viral proteins that may contribute to HTLV-1-induced pathogenesis. We found exosomes derived from infected cells to contain Tax protein and proinflammatory mediators as well as viral mRNA transcripts, including Tax, HBZ, and Env. Furthermore, we observed that exosomes released from HTLV-1-infected Tax-expressing cells contributed to enhanced survival of exosome-recipient cells when treated with Fas antibody. This survival was cFLIP-dependent, with Tax showing induction of NF-κB in exosome-recipient cells. Finally, IL-2-dependent CTLL-2 cells that received Tax-containing exosomes were protected from apoptosis through activation of AKT. Similar experiments with primary cultures showed protection and survival of peripheral blood mononuclear cells even in the absence of phytohemagglutinin/IL-2. Surviving cells contained more phosphorylated Rb, consistent with the role of Tax in regulation of the cell cycle. Collectively, these results suggest that exosomes may play an important role in extracellular delivery of functional HTLV-1 proteins and mRNA to recipient cells. PMID:24939845

Characteristics of allelic gene expression in human brain cells from single-cell RNA-seq data analysis.

PubMed

Zhao, Dejian; Lin, Mingyan; Pedrosa, Erika; Lachman, Herbert M; Zheng, Deyou

2017-11-10

Monoallelic expression of autosomal genes has been implicated in human psychiatric disorders. However, there is a paucity of allelic expression studies in human brain cells at the single cell and genome wide levels. In this report, we reanalyzed a previously published single-cell RNA-seq dataset from several postmortem human brains and observed pervasive monoallelic expression in individual cells, largely in a random manner. Examining single nucleotide variants with a predicted functional disruption, we found that the "damaged" alleles were overall expressed in fewer brain cells than their counterparts, and at a lower level in cells where their expression was detected. We also identified many brain cell type-specific monoallelically expressed genes. Interestingly, many of these cell type-specific monoallelically expressed genes were enriched for functions important for those brain cell types. In addition, function analysis showed that genes displaying monoallelic expression and correlated expression across neuronal cells from different individual brains were implicated in the regulation of synaptic function. Our findings suggest that monoallelic gene expression is prevalent in human brain cells, which may play a role in generating cellular identity and neuronal diversity and thus increasing the complexity and diversity of brain cell functions.

Forward-biased current annealing of radiation degraded indium phosphide and gallium arsenide solar cells

NASA Technical Reports Server (NTRS)

Michael, Sherif; Cypranowski, Corinne; Anspaugh, Bruce

1990-01-01

The preliminary results of a novel approach to low-temperature annealing of previously irradiated indium phosphide and gallium arsenide solar cells are reported. The technique is based on forward-biased current annealing. The two types of III-V solar cells were irradiated with 1-MeV electrons to a fluence level of (1-10) x 10 to the 14th electrons/sq cm. Several annealing attempts were made, varying all conditions. Optimum annealing was achieved when cells were injected with minority currents at a constant 90 C. The current density for each type of cell was also determined. Significant recovery of degraded parameters was achieved in both cases. However, the InP cell recovery notably exceeded the recovery in GaAs cells. The recovery is thought to be caused by current-stimulated reordering of the radiator-induced displacement damage. Both types of cell were then subjected to several cycles of irradiation and annealing. The results were also very promising. The significant recovery of degraded cell parameters at low temperature might play a major role in considerably extending the end of life of future spacecraft.

Characterization of atrial natriuretic peptide receptors in brain microvessel endothelial cells

NASA Technical Reports Server (NTRS)

Whitson, Peggy A.; Huls, M. H.; Sams, Clarence F.

1989-01-01

In view of the suggestions by Chabrier et al. (1987) and Steardo and Nathanson (1987) that atrial natriuretic peptide (ANP) may play a role in the fluid homeostasis of the brain, the ANP receptors in primary cultures of bovine brain microvessel endothelian cells were quantitated and characterized. Results of partition binding studies and the effect of cGMP additions indicated the presence of at least two types of ANP receptors, with the majority of the receptors being the nonguanylate cyclase coupled receptors. The presence of at least two ANP receptor types suggests an active role for ANP in regulating brain endothelial cell function.

Characterization of slow-cycling cells in the mouse cochlear lateral wall

PubMed Central

Ogawa, Kaoru

2017-01-01

Cochlear spiral ligament fibrocytes (SLFs) play essential roles in the physiology of hearing including ion recycling and the generation of endocochlear potential. In adult animals, SLFs can repopulate after damages, yet little is known about the characteristics of proliferating cells that support SLFs’ self-renewal. Here we report in detail about the characteristics of cycling cells in the spiral ligament (SL). Fifteen P6 mice and six noise-exposed P28 mice were injected with 5-bromo-2′-deoxyuridine (BrdU) for 7 days and we chased BrdU retaining cells for as long as 60 days. Immunohistochemistry revealed that the BrdU positive IB4 (an endotherial marker) negative cells expressed an early SLF marker Pou3f4 but negative for cleaved-Caspase 3. Marker studies revealed that type 3 SLFs displayed significantly higher percentage of BrdU+ cells compared to other subtypes. Notably, the cells retained BrdU until P72, demonstrating they were dividing slowly. In the noise-damaged mice, in contrast to the loss of the other types, the number of type 3 SLFs did not altered and the BrdU incorporating- phosphorylated Histone H3 positive type 3 cells were increased from day 1 to 14 after noise exposure. Furthermore, the cells repopulating type 1 area, where the cells diminished profoundly after damage, were positive for the type 3 SLF markers. Collectively, in the latral wall of the cochlea, type 3 SLFs have the stem cell capacity and may contribute to the endogenous regeneration of lateral wall spiral ligament. Manipulating type 3 cells may be employed for potential regenerative therapies. PMID:28632772

Expression profile of amh/Amh during bi-directional sex change in the protogynous orange-spotted grouper Epinephelus coioides.

PubMed

Wu, Guan-Chung; Li, Hau-Wen; Tey, Wei-Guan; Lin, Chien-Ju; Chang, Ching-Fong

2017-01-01

Gonadal differentiation is tightly regulated by the initial sex determining gene and the downstream sex-related genes in vertebrates. However, sex change in fish can alter the sexual fate from one sex to the other. Chemical-induced maleness in the protogynous orange-spotted grouper is transient, and a reversible sex change occurs after the chemical treatment is withdrawn. We used these characteristics to study Amh signaling during bi-directional sex change in the grouper. We successfully induced the female-to-male sex change by chemical (aromatase inhibitor, AI, or methyltestosterone, MT) treatment. A dormant gonad (a low proliferation rate of early germ cells and no characteristics of both sexes) was found during the transient phase of reversible male-to-female sex change after the withdrawal of chemical administration. Our results showed that amh (anti-mullerian hormone) and its receptor amhr2 (anti-mullerian hormone receptor type 2) were significantly increased in the gonads during the process of female-to-male sex change. Amh is expressed in the Sertoli cells surrounding the type A spermatogonia in the female-to-male grouper. Male-related gene (dmrt1 and sox9) expression was immediately decreased in MT-terminated males during the reversible male-to-female sex change. However, Amh expression was found in the surrounding cells of type A spermatogonia-like cells during the transient phase of reversible male-to-female sex change. This phenomenon is correlated with the dormancy of type A spermatogonia-like cells. Thus, Amh signaling is suggested to play roles in regulating male differentiation during the female-to-male sex change and in inhibiting type-A spermatogonia-like cell proliferation/differentiation during the reversible male-to-female sex change. We suggest that Amh signaling might play dual roles during bi-directional sex change in grouper.

Expression profile of amh/Amh during bi-directional sex change in the protogynous orange-spotted grouper Epinephelus coioides

PubMed Central

Wu, Guan-Chung; Li, Hau-Wen; Tey, Wei-Guan; Lin, Chien-Ju; Chang, Ching-Fong

2017-01-01

Gonadal differentiation is tightly regulated by the initial sex determining gene and the downstream sex-related genes in vertebrates. However, sex change in fish can alter the sexual fate from one sex to the other. Chemical-induced maleness in the protogynous orange-spotted grouper is transient, and a reversible sex change occurs after the chemical treatment is withdrawn. We used these characteristics to study Amh signaling during bi-directional sex change in the grouper. We successfully induced the female-to-male sex change by chemical (aromatase inhibitor, AI, or methyltestosterone, MT) treatment. A dormant gonad (a low proliferation rate of early germ cells and no characteristics of both sexes) was found during the transient phase of reversible male-to-female sex change after the withdrawal of chemical administration. Our results showed that amh (anti-mullerian hormone) and its receptor amhr2 (anti-mullerian hormone receptor type 2) were significantly increased in the gonads during the process of female-to-male sex change. Amh is expressed in the Sertoli cells surrounding the type A spermatogonia in the female-to-male grouper. Male-related gene (dmrt1 and sox9) expression was immediately decreased in MT-terminated males during the reversible male-to-female sex change. However, Amh expression was found in the surrounding cells of type A spermatogonia-like cells during the transient phase of reversible male-to-female sex change. This phenomenon is correlated with the dormancy of type A spermatogonia-like cells. Thus, Amh signaling is suggested to play roles in regulating male differentiation during the female-to-male sex change and in inhibiting type-A spermatogonia-like cell proliferation/differentiation during the reversible male-to-female sex change. We suggest that Amh signaling might play dual roles during bi-directional sex change in grouper. PMID:29016690

Improving the photovoltaic performance of the all-solid-state TiO2 NR/CuInS2 solar cell by hydrogen plasma treatment.

PubMed

Chen, Bingfeng; Niu, Wenzhe; Lou, Zirui; Ye, Zhizhen; Zhu, Liping

2018-07-06

The interfacial properties of the heterojunction between p-type and n-type materials play an important role in the performance of the solar cell. In this paper, a p-type CuInS 2 film was deposited on TiO 2 nanorod arrays by spin coating to fabricate an all-solid-state solar cell and the TiO 2 nanorod arrays were treated with hydrogen plasma(H:TiO 2 ) to ameliorate the interfacial properties. The influence of the hydrogen plasma treatment on the performance of the solar cell was investigated. The short-circuit current density was obviously raised and the power conversion efficiency of the solar cell improved to 0.30%, which is three times that of solar cells without hydrogen plasma treatment. The enhancement of the performance is attributed to not only the enhancement of carrier separation and transport, but the reduction of the recombination of electrons and holes, which is caused by hydrogen plasma treatment.

Improving the photovoltaic performance of the all-solid-state TiO2 NR/CuInS2 solar cell by hydrogen plasma treatment

NASA Astrophysics Data System (ADS)

Chen, Bingfeng; Niu, Wenzhe; Lou, Zirui; Ye, Zhizhen; Zhu, Liping

2018-07-01

The interfacial properties of the heterojunction between p-type and n-type materials play an important role in the performance of the solar cell. In this paper, a p-type CuInS2 film was deposited on TiO2 nanorod arrays by spin coating to fabricate an all-solid-state solar cell and the TiO2 nanorod arrays were treated with hydrogen plasma(H:TiO2) to ameliorate the interfacial properties. The influence of the hydrogen plasma treatment on the performance of the solar cell was investigated. The short-circuit current density was obviously raised and the power conversion efficiency of the solar cell improved to 0.30%, which is three times that of solar cells without hydrogen plasma treatment. The enhancement of the performance is attributed to not only the enhancement of carrier separation and transport, but the reduction of the recombination of electrons and holes, which is caused by hydrogen plasma treatment.

Chick cerebellar Purkinje cells express omega-conotoxin GVIA-sensitive rather than funnel-web spider toxin-sensitive calcium channels.

PubMed

Angulo, M C; Parra, P; Dieudonné, S

1998-03-01

Voltage-gated calcium channels form a complex family of distinct molecular entities which participate in multiple neuronal functions. In cerebellar Purkinje cells these channels contribute to the characteristic electrophysiological pattern of complex spikes, first described in birds and later in mammals. A specific calcium channel, the P-type channel, has been shown to mediate the majority of the voltage-gated calcium flux in mammalian Purkinje cells. P-type channels play an essential role in synaptic transmission of mammalian cerebellum. It is unclear whether the P-type calcium channel is present in birds. Studies in chick synaptosomal preparations show that the pharmacological profile of calcium channels is complex and suggest a minimal expression of the P-type channel in avian central nervous system. In the present work, we studied voltage-gated calcium channels in dissociated chick cerebellar Purkinje cells to examine the presence of different calcium channel types. Purkinje cells were used because, in mammals, they express predominantly P-type channels and because the morphology of these cells is thought to be phylogenetically conserved. We found that omega-conotoxin GVIA (omega-CgTx GVIA), a specific antagonist of N-type calcium channel, rather than the synthetic funnel-web spider toxin (sFTX), a P-type channel antagonist, blocks the majority of the barium current flowing through calcium channels in chick Purkinje neurons.

Calmodulin protects cells from death under normal growth conditions and mitogenic starvation but plays a mediating role in cell death upon B-cell receptor stimulation

PubMed Central

Schmalzigaug, Robert; Ye, Qunrui; Berchtold, Martin W

2001-01-01

Calmodulin (CaM) is the main intracellular Ca2+ sensor protein responsible for mediating Ca2+ triggered processes. Chicken DT40 lymphoma B cells express CaM from the two genes, CaMI and CaMII. Here we report the phenotypes of DT40 cells with the CaMII gene knocked out. The disruption of the CaMII gene causes the intracellular CaM level to decrease by 60%. CaMII−/− cells grow more slowly and die more frequently as compared to wild type (wt) cells but do not exhibit significant differences in their cell cycle profile. Both phenotypes are more pronounced at reduced serum concentrations. Upon stimulation of the B-cell receptor (BCR), the resting Ca2+ levels remain elevated after the initial transient in CaMII−/− cells. Despite higher Ca2+ resting levels, the CaMII−/− cells are partially protected from BCR induced apoptosis indicating that CaM plays a dual role in apoptotic processes. PMID:11454062

TOPICAL REVIEW: Artificial extracellular matrix for embryonic stem cell cultures: a new frontier of nanobiomaterials

NASA Astrophysics Data System (ADS)

Amranul Haque, Md; Nagaoka, Masato; Hexig, Bayar; Akaike, Toshihiro

2010-02-01

Nanobiomaterials can play a central role in regenerative medicine and tissue engineering by facilitating cellular behavior and function, such as those where extracellular matrices (ECMs) direct embryonic stem (ES) cell morphogenesis, proliferation, differentiation and apoptosis. However, controlling ES cell proliferation and differentiation using matrices from natural sources is still challenging due to complex and heterogeneous culture conditions. Moreover, the systemic investigation of the regulation of self-renewal and differentiation to lineage specific cells depends on the use of defined and stress-free culture conditions. Both goals can be achieved by the development of biomaterial design targeting ECM or growth factors for ES cell culture. This targeted application will benefit from expansion of ES cells for transplantation, as well as the production of a specific differentiated cell type either by controlling the differentiation in a very specific pathway or by elimination of undesirable cell types.

Investigating the Role of Helicobacter pylori PriA Protein.

PubMed

Singh, Aparna; Blaskovic, Dusan; Joo, Jungsoo; Yang, Zhen; Jackson, Sharon H; Coleman, William G; Yan, Ming

2016-08-01

In bacteria, PriA protein, a conserved DEXH-type DNA helicase, plays a central role in replication restart at stalled replication forks. Its unique DNA binding property allows it to recognize and stabilize stalled forks and the structures derived from them. PriA plays a very critical role in replication fork stabilization and DNA repair in E. coli and N. gonorrhoeae. In our in vivo expression technology screen, priA gene was induced in vivo when Helicobacter pylori infects mouse stomach. We decided to elucidate the role of H. pylori PriA protein in survival in mouse stomach, survival in gastric epithelial cells and macrophage cells, DNA repair, acid stress, and oxidative stress. The priA null mutant strain was unable to colonize mice stomach mucosa after long-term infections. Mouse colonization was observed after 1 week of infection, but the levels were much lower than the wild-type HpSS1 strain. PriA protein was found to be important for intracellular survival of epithelial cell-/macrophage cell-ingested H. pylori. Also, a priA null mutant was more sensitive to DNA-damaging agents and was much more sensitive to acid and oxidative stress as compared to the wild-type strain. These data suggest that the PriA protein is needed for survival and persistence of H. pylori in mice stomach mucosa. © 2016 John Wiley & Sons Ltd.

Dramatic performance of Clostridium thermocellum explained by its wide range of cellulase modalities

DOE PAGES

Xu, Qi; Resch, Michael G.; Podkaminer, Kara; ...

2016-02-05

Clostridium thermocellum is the most efficient microorganism for solubilizing lignocellulosic biomass known to date. Its high cellulose digestion capability is attributed to efficient cellulases consisting of both a free-enzyme system and a tethered cellulosomal system wherein carbohydrate active enzymes (CAZymes) are organized by primary and secondary scaffoldin proteins to generate large protein complexes attached to the bacterial cell wall. This study demonstrates that C. thermocellum also uses a type of cellulosomal system not bound to the bacterial cell wall, called the “cell-free” cellulosomal system. The cell-free cellulosome complex can be seen as a “long range cellulosome” because it can diffusemore » away from the cell and degrade polysaccharide substrates remotely from the bacterial cell. The contribution of these two types of cellulosomal systems in C. thermocellum was elucidated by characterization of mutants with different combinations of scaffoldin gene deletions. The primary scaffoldin, CipA, was found to play the most important role in cellulose degradation by C. thermocellum, whereas the secondary scaffoldins have less important roles. Additionally, the distinct and efficient mode of action of the C. thermocellum exoproteome, wherein the cellulosomes splay or divide biomass particles, changes when either the primary or secondary scaffolds are removed, showing that the intact wild-type cellulosomal system is necessary for this essential mode of action. As a result, this new transcriptional and proteomic evidence shows that a functional primary scaffoldin plays a more important role compared to secondary scaffoldins in the proper regulation of CAZyme genes, cellodextrin transport, and other cellular functions.« less

Dramatic performance of Clostridium thermocellum explained by its wide range of cellulase modalities

PubMed Central

Xu, Qi; Resch, Michael G.; Podkaminer, Kara; Yang, Shihui; Baker, John O.; Donohoe, Bryon S.; Wilson, Charlotte; Klingeman, Dawn M.; Olson, Daniel G.; Decker, Stephen R.; Giannone, Richard J.; Hettich, Robert L.; Brown, Steven D.; Lynd, Lee R.; Bayer, Edward A.; Himmel, Michael E.; Bomble, Yannick J.

2016-01-01

Clostridium thermocellum is the most efficient microorganism for solubilizing lignocellulosic biomass known to date. Its high cellulose digestion capability is attributed to efficient cellulases consisting of both a free-enzyme system and a tethered cellulosomal system wherein carbohydrate active enzymes (CAZymes) are organized by primary and secondary scaffoldin proteins to generate large protein complexes attached to the bacterial cell wall. This study demonstrates that C. thermocellum also uses a type of cellulosomal system not bound to the bacterial cell wall, called the “cell-free” cellulosomal system. The cell-free cellulosome complex can be seen as a “long range cellulosome” because it can diffuse away from the cell and degrade polysaccharide substrates remotely from the bacterial cell. The contribution of these two types of cellulosomal systems in C. thermocellum was elucidated by characterization of mutants with different combinations of scaffoldin gene deletions. The primary scaffoldin, CipA, was found to play the most important role in cellulose degradation by C. thermocellum, whereas the secondary scaffoldins have less important roles. Additionally, the distinct and efficient mode of action of the C. thermocellum exoproteome, wherein the cellulosomes splay or divide biomass particles, changes when either the primary or secondary scaffolds are removed, showing that the intact wild-type cellulosomal system is necessary for this essential mode of action. This new transcriptional and proteomic evidence shows that a functional primary scaffoldin plays a more important role compared to secondary scaffoldins in the proper regulation of CAZyme genes, cellodextrin transport, and other cellular functions. PMID:26989779

Metainflammation in Diabetic Coronary Artery Disease: Emerging Role of Innate and Adaptive Immune Responses

PubMed Central

Madhumitha, Haridoss

2016-01-01

Globally, noncommunicable chronic diseases such as Type-2 Diabetes Mellitus (T2DM) and Coronary Artery Disease (CAD) are posing a major threat to the world. T2DM is known to potentiate CAD which had led to the coining of a new clinical entity named diabetic CAD (DM-CAD), leading to excessive morbidity and mortality. The synergistic interaction between these two comorbidities is through sterile inflammation which is now being addressed as metabolic inflammation or metainflammation, which plays a pivotal role during both early and late stages of T2DM and also serves as a link between T2DM and CAD. This review summarises the current concepts on the role played by both innate and adaptive immune responses in setting up metainflammation in DM-CAD. More specifically, the role played by innate pattern recognition receptors (PRRs) like Toll-like receptors (TLRs), NOD1-like receptors (NLRs), Rig-1-like receptors (RLRs), and C-type lectin like receptors (CLRs) and metabolic endotoxemia in fuelling metainflammation in DM-CAD would be discussed. Further, the role played by adaptive immune cells (Th1, Th2, Th17, and Th9 cells) in fuelling metainflammation in DM-CAD will also be discussed. PMID:27610390

Hybrid- and complex-type N-glycans are not essential for Newcastle disease virus infection and fusion of host cells.

PubMed

Sun, Qing; Zhao, Lixiang; Song, Qingqing; Wang, Zheng; Qiu, Xusheng; Zhang, Wenjun; Zhao, Mingjun; Zhao, Guo; Liu, Wenbo; Liu, Haiyan; Li, Yunsen; Liu, Xiufan

2012-03-01

N-linked glycans are composed of three major types: high-mannose (Man), hybrid or complex. The functional role of hybrid- and complex-type N-glycans in Newcastle disease virus (NDV) infection and fusion was examined in N-acetylglucosaminyltransferase I (GnT I)-deficient Lec1 cells, a mutant Chinese hamster ovary (CHO) cell incapable of synthesizing hybrid- and complex-type N-glycans. We used recombinant NDV expressing green fluorescence protein or red fluorescence protein to monitor NDV infection, syncytium formation and viral yield. Flow cytometry showed that CHO-K1 and Lec1 cells had essentially the same degree of NDV infection. In contrast, Lec2 cells were found to be resistant to NDV infection. Compared with CHO-K1 cells, Lec1 cells were shown to more sensitive to fusion induced by NDV. Viral attachment was found to be comparable in both lines. We found that there were no significant differences in the yield of progeny virus produced by both CHO-K1 and Lec1 cells. Quantitative analysis revealed that NDV infection and fusion in Lec1 cells were also inhibited by treatment with sialidase. Pretreatment of Lec1 cells with Galanthus nivalis agglutinin specific for terminal α1-3-linked Man prior to inoculation with NDV rendered Lec1 cells less sensitive to cell-to-cell fusion compared with mock-treated Lec1 cells. Treatment of CHO-K1 and Lec1 cells with tunicamycin, an inhibitor of N-glycosylation, significantly blocked fusion and infection. In conclusion, our results suggest that hybrid- and complex-type N-glycans are not required for NDV infection and fusion. We propose that high-Man-type N-glycans could play an important role in the cell-to-cell fusion induced by NDV.

Adhesive interactions of human multiple myeloma cell lines with different extracellular matrix molecules.

PubMed

Kibler, C; Schermutzki, F; Waller, H D; Timpl, R; Müller, C A; Klein, G

1998-06-01

Multiple myeloma represents a human B cell malignancy which is characterized by a predominant localization of the malignant cell clone within the bone marrow. With the exception of the terminal stage of the disease the myeloma tumor cells do not circulate in the peripheral blood. The bone marrow microenvironment is believed to play an important role in homing, proliferation and terminal differentiation of myeloma cells. Here we have studied the expression of several extracellular matrix (ECM) molecules in the bone marrow of multiple myeloma patients and analyzed their adhesive capacities with four different human myeloma-derived cell lines. All ECM molecules analyzed (tenascin, laminin, fibronectin, collagen types I, III, V and VI) could be detected in bone marrow cryostat sections of multiple myeloma patients. Adhesion assays showed that only laminin, the microfibrillar collagen type VI and fibronectin were strong adhesive components for the myeloma cell lines U266, IM-9, OPM-2 and NCI-H929. Tenascin and collagen type I were only weak adhesive substrates for these myeloma cells. Adhesion to laminin and fibronectin was beta 1-integrin-mediated since addition of anti-beta 1-integrin antibodies could inhibit the binding of the four different cell types to both matrix molecules. In contrast, integrins do not seem to be involved in binding of the myeloma cells to collagen type VI. Instead, inhibition of binding by heparin suggested that membrane-bound heparan sulfate proteoglycans are responsible ligands for binding to collagen type VI. Adhesion assays with several B-cell lines resembling earlier differentiation stages revealed only weak interactions with tenascin and no interactions with collagen type VI, laminin or fibronectin. In summary, the interactions of human myeloma cells with the extracellular matrix may explain the specific retention of the plasma cells within the bone marrow.

Effect of Diabetes Mellitus on Adipocyte-Derived Stem Cells in Rat.

PubMed

Jumabay, Medet; Moon, Jeremiah H; Yeerna, Huwate; Boström, Kristina I

2015-11-01

Diabetes mellitus affects the adipose tissue and mesenchymal stem cells derived from the adipose stroma and other tissues. Previous reports suggest that bone morphogenetic protein 4 (BMP4) is involved in diabetic complications, at the same time playing an important role in the maintenance of stem cells. In this study, we used rats transgenic for human islet amyloid polypeptide (HIP rats), a model of type 2 diabetes, to study the effect of diabetes on adipocyte-derived stem cells, referred to as dedifferentiated fat (DFAT) cells. Our results show that BMP4 expression in inguinal adipose tissue is significantly increased in HIP rats compared to controls, whereas matrix Gla protein (MGP), an inhibitor of BMP4 is decreased as determined by quantitative PCR, and immunofluorescence. In addition, adipose vascularity and expression of multiple endothelial cell markers was increased in the diabetic tissue, visualized by immunofluorescence for endothelial markers. The endothelial markers co-localized with the enhanced BMP4 expression, suggesting that vascular cells play a role BMP4 induction. The DFAT cells are multipotent stem cells derived from white mature adipocytes that undergo endothelial and adipogenic differentiation. DFAT cells prepared from the inguinal adipose tissue in HIP rats exhibited enhanced proliferative capacity compared to wild type. In addition, their ability to undergo both endothelial cell and adipogenic lineage differentiation was enhanced, as well as their response to BMP4, as assessed by lineage marker expression. We conclude that the DFAT cells are affected by diabetic changes and may contribute to the adipose dysfunction in diabetes. © 2015 Wiley Periodicals, Inc.

Cell surface expression of channel catfish leukocyte immune-type receptors (IpLITRs) and recruitment of both Src homology 2 domain-containing protein tyrosine phosphatase (SHP)-1 and SHP-2.

PubMed

Montgomery, Benjamin C S; Mewes, Jacqueline; Davidson, Chelsea; Burshtyn, Deborah N; Stafford, James L

2009-04-01

Channel catfish leukocyte immune-type receptors (IpLITRs) are immunoglobulin superfamily (IgSF) members believed to play a role in the control and coordination of cellular immune responses in teleost. Putative stimulatory and inhibitory IpLITRs are co-expressed by different types of catfish immune cells (e.g. NK cells, T cells, B cells, and macrophages) but their signaling potential has not been determined. Following cationic polymer-mediated transfections into human cell lines we examined the surface expression, tyrosine phosphorylation, and phosphatase recruitment potential of two types of putative inhibitory IpLITRs using 'chimeric' expression constructs and an epitope-tagged 'native' IpLITR. We also cloned and expressed the teleost Src homology 2 domain-containing protein tyrosine phosphatases (SHP)-1 and SHP-2 and examined their expression in adult tissues and developing zebrafish embryos. Co-immunoprecipitation experiments support the inhibitory signaling potential of distinct IpLITR-types that bound both SHP-1 and SHP-2 following the phosphorylation of tyrosine residues within their cytoplasmic tail (CYT) regions. Phosphatase recruitment by IpLITRs represents an important first step in understanding their influence on immune cell effector functions and suggests that certain inhibitory signaling pathways are conserved among vertebrates.

[The role of chromogranin-A and its derived peptide, WE-14 in the development of type 1 diabetes mellitus].

PubMed

Herold, Zoltán; Nagy, Péter; Patócs, Attila; Somogyi, Anikó

2015-02-01

Chromogranin-A is a member of the granine protein family. It is produced in neuroendocrine cells via secretory granules. Many cleavage proteins are formed from chromogranin-A, from which some have well known biological activity, while the function of others is not yet fully known. Serum chromogranin-A levels are used in neuroendocrine tumour diagnostics. Recent studies showed that one of its cleavage protein, WE-14 may also play a role in the development of type 1 diabetes. WE-14 may function as an autoantigen for T-cells involved in the destruction of β-cells. This mechanism was previously observed only in non-obese diabetic mice. Novel results show that WE-14 also serves as a target for autoreactive cells in newly diagnosed type 1 diabetic patients as well, which reaction can be increased with transglutaminase. In this paper the authors summarize the recent knowledge about chromogranin-A and its potential role in the pathomechanism of type 1 diabetes mellitus.

Cell type-specific long-range connections of basal forebrain circuit.

PubMed

Do, Johnny Phong; Xu, Min; Lee, Seung-Hee; Chang, Wei-Cheng; Zhang, Siyu; Chung, Shinjae; Yung, Tyler J; Fan, Jiang Lan; Miyamichi, Kazunari; Luo, Liqun; Dan, Yang

2016-09-19

The basal forebrain (BF) plays key roles in multiple brain functions, including sleep-wake regulation, attention, and learning/memory, but the long-range connections mediating these functions remain poorly characterized. Here we performed whole-brain mapping of both inputs and outputs of four BF cell types - cholinergic, glutamatergic, and parvalbumin-positive (PV+) and somatostatin-positive (SOM+) GABAergic neurons - in the mouse brain. Using rabies virus -mediated monosynaptic retrograde tracing to label the inputs and adeno-associated virus to trace axonal projections, we identified numerous brain areas connected to the BF. The inputs to different cell types were qualitatively similar, but the output projections showed marked differences. The connections to glutamatergic and SOM+ neurons were strongly reciprocal, while those to cholinergic and PV+ neurons were more unidirectional. These results reveal the long-range wiring diagram of the BF circuit with highly convergent inputs and divergent outputs and point to both functional commonality and specialization of different BF cell types.

A family business: stem cell progeny join the niche to regulate homeostasis.

PubMed

Hsu, Ya-Chieh; Fuchs, Elaine

2012-01-23

Stem cell niches, the discrete microenvironments in which the stem cells reside, play a dominant part in regulating stem cell activity and behaviours. Recent studies suggest that committed stem cell progeny become indispensable components of the niche in a wide range of stem cell systems. These unexpected niche inhabitants provide versatile feedback signals to their stem cell parents. Together with other heterologous cell types that constitute the niche, they contribute to the dynamics of the microenvironment. As progeny are often located in close proximity to stem cell niches, similar feedback regulations may be the underlying principles shared by different stem cell systems.

A family business: stem cell progeny join the niche to regulate homeostasis

PubMed Central

Hsu, Ya-Chieh; Fuchs, Elaine

2012-01-01

Stem cell niches, the discrete microenvironments in which the stem cells reside, play a dominant part in regulating stem cell activity and behaviours. Recent studies suggest that committed stem cell progeny become indispensable components of the niche in a wide range of stem cell systems. These unexpected niche inhabitants provide versatile feedback signals to their stem cell parents. Together with other heterologous cell types that constitute the niche, they contribute to the dynamics of the microenvironment. As progeny are often located in close proximity to stem cell niches, similar feedback regulations may be the underlying principles shared by different stem cell systems. PMID:22266760

Hepatic inclusions during interferon therapy in chronic viral hepatitis.

PubMed

Schaff, Z; Hoofnagle, J H; Grimley, P M

1986-01-01

Two types of cytomembranous abnormalities were identified for the first time in liver biopsies from patients with chronic active type B hepatitis during treatment with recombinant alpha-interferon. Tubuloreticular inclusions were present in the hepatic endothelial cells, Kupffer cells and perisinusoidal cells of liver biopsies from both patients, and they were absent in liver biopsies obtained before treatment. Cylindrical confronting lamellae, having "test tube" or "ring-shape" forms were observed in the cytoplasm both of Kupffer cells and macrophages in the second liver biopsy of one of the patients. The findings suggest that interferon can be involved in the pathogenesis of both cytomembranous abnormalities, but that additional biological factors may play a role in formation of the cylindrical confronting lamellae.

DNMT gene expression and methylome in Marek’s disease resistant and susceptible chickens prior to and following infection by MDV

USDA-ARS?s Scientific Manuscript database

Marek’s disease (MD) is characterized as a T cell lymphoma induced by a cell-associated a-herpesvirus, Marek’s disease virus type 1 (MDV1). As with many viral infectious diseases, DNA methylation variations were observed in the progression of MD; these variations are thought to play an important rol...

Differences in beta-cell function and insulin secretion in Black vs. White obese adolescents: Do incretin hormones play a role?

USDA-ARS?s Scientific Manuscript database

Black youth are at higher risk for type 2 diabetes (T2D) than their White peers. Previously we demonstrated that for the same degree of insulin sensitivity, Black youth have an upregulated beta-cell function and insulin hypersecretion, in response to intravenous (IV) glucose, compared with Whites. T...

Are There Roles for Brain Cell Senescence in Aging and Neurodegenerative Disorders?

PubMed Central

Tan, Florence C. C.; Hutchison, Emmette R.; Eitan, Erez; Mattson, Mark P.

2014-01-01

The term cellular senescence was introduced more than five decades ago to describe the state of growth arrest observed in aging cells. Since this initial discovery, the phenotypes associated with cellular senescence have expanded beyond growth arrest to include alterations in cellular metabolism, secreted cytokines, epigenetic regulation and protein expression. Recently, senescence has been shown to play an important role in vivo not only in relation to aging, but also during embryonic development. Thus, cellular senescence serves different purposes and comprises a wide range of distinct phenotypes across multiple cell types. Whether all cell types, including post-mitotic neurons, are capable of entering into a senescent state remains unclear. In this review we examine recent data that suggest that cellular senescence plays a role in brain aging and, notably, may not be limited to glia but also neurons. We suggest that there is a high level of similarity between some of the pathological changes that occur in the brain in Alzheimer’s and Parkinson’s diseases and those phenotypes observed in cellular senescence, leading us to propose that neurons and glia can exhibit hallmarks of senescence previously documented in peripheral tissues. PMID:25305051

Are there roles for brain cell senescence in aging and neurodegenerative disorders?

PubMed

Tan, Florence C C; Hutchison, Emmette R; Eitan, Erez; Mattson, Mark P

2014-12-01

The term cellular senescence was introduced more than five decades ago to describe the state of growth arrest observed in aging cells. Since this initial discovery, the phenotypes associated with cellular senescence have expanded beyond growth arrest to include alterations in cellular metabolism, secreted cytokines, epigenetic regulation and protein expression. Recently, senescence has been shown to play an important role in vivo not only in relation to aging, but also during embryonic development. Thus, cellular senescence serves different purposes and comprises a wide range of distinct phenotypes across multiple cell types. Whether all cell types, including post-mitotic neurons, are capable of entering into a senescent state remains unclear. In this review we examine recent data that suggest that cellular senescence plays a role in brain aging and, notably, may not be limited to glia but also neurons. We suggest that there is a high level of similarity between some of the pathological changes that occur in the brain in Alzheimer's and Parkinson's diseases and those phenotypes observed in cellular senescence, leading us to propose that neurons and glia can exhibit hallmarks of senescence previously documented in peripheral tissues.

Novel Role for Interleukin-17 in Enhancing Type 1 Helper T Cell Immunity in the Female Genital Tract following Mucosal Herpes Simplex Virus 2 Vaccination

PubMed Central

Bagri, Puja; Anipindi, Varun C.; Nguyen, Philip V.; Vitali, Danielle; Stämpfli, Martin R.

2017-01-01

ABSTRACT It is well established that interferon gamma (IFN-γ) production by CD4+ T cells is critical for antiviral immunity against herpes simplex virus 2 (HSV-2) genital infection. However, the role of interleukin-17A (IL-17A) production by CD4+ T cells in HSV-2 antiviral immunity is yet to be elucidated. Here we demonstrate that IL-17A plays an important role in enhancing antiviral T helper type 1 (Th1) responses in the female genital tract (FGT) and is essential for effective protection conferred by HSV-2 vaccination. While IL-17A did not play a critical role during primary genital HSV-2 infection, seen by lack of differences in susceptibility between IL-17A-deficient (IL-17A−/−) and wild-type (WT) C57BL/6 mice, it was critical for mediating antiviral responses after challenge/reexposure. Compared to WT mice, IL-17A−/− mice (i) infected intravaginally and reexposed or (ii) vaccinated intranasally and challenged intravaginally demonstrated poor outcomes. Following intravaginal HSV-2 reexposure or challenge, vaccinated IL-17A−/− mice had significantly higher mortality, greater disease severity, higher viral shedding, and higher levels of proinflammatory cytokines and chemokines in vaginal secretions. Furthermore, IL-17A−/− mice had impaired Th1 cell responses after challenge/reexposure, with significantly lower proportions of vaginal IFN-γ+ CD4+ T cells. The impaired Th1 cell responses in IL-17A−/− mice coincided with smaller populations of IFN-γ+ CD4+ tissue resident memory T (TRM) cells in the genital tract postimmunization. Taken together, these findings describe a novel role for IL-17A in regulating antiviral IFN-γ+ Th1 cell immunity in the vaginal tract. This strategy could be exploited to enhance antiviral immunity following HSV-2 vaccination. IMPORTANCE T helper type 1 (Th1) immunity, specifically interferon gamma (IFN-γ) production by CD4+ T cells, is critical for protection against genital herpesvirus (HSV-2) infection, and enhancing this response can potentially help improve disease outcomes. Our study demonstrated that interleukin-17A (IL-17A) plays an essential role in enhancing antiviral Th1 responses in the female genital tract (FGT). We found that in the absence of IL-17A, preexposed and vaccinated mice showed poor disease outcomes and were unable to overcome HSV-2 reexposure/challenge. IL-17A-deficient mice (IL-17A−/−) had smaller populations of IFN-γ+ CD4+ tissue resident memory T (TRM) cells in the genital tract postimmunization than did wild-type (WT) mice, which coincided with attenuated Th1 responses postchallenge. This has important implications for developing effective vaccines against HSV-2, as we propose that strategies inducing IL-17A in the genital tract may promote more effective Th1 cell immunity and better overall protection. PMID:28956763

Requirement for erythroblast-macrophage protein (Emp) in definitive erythropoiesis.

PubMed

Soni, Shivani; Bala, Shashi; Hanspal, Manjit

2008-01-01

Emp, erythroblast-macrophage protein was initially identified as a mediator of erythroblast-macrophage interactions during erythroid differentiation. More recent studies have shown that targeted disruption of Emp leads to abnormal erythropoiesis in the fetal liver, and fetal demise. To further address the activity of Emp in the hematopoietic lineage in adult bone marrow, we conducted fetal liver HSC reconstitution assay. Emp null fetal liver cells were transplanted into lethally irradiated wild-type sibling mice, and assessed the erythropoietic activity. We found that Emp null cells rescued lethally irradiated mice with efficiency comparable to that of wild-type cells. However, the recipients of Emp null cells showed abnormal erythropoiesis as indicated by the presence of persistent anemia, extensive extramedullary erythropoiesis, and increased apoptosis of erythroid precursors. Extramedullary erythropoiesis suggests perturbed interactions between the Emp-deficient hematopoietic cells and the wild-type niche. Furthermore, in spleen colony-forming unit assays, proliferation rates of the Emp null cells were greater than those of the wild-type cells. Similarly, in vitro burst-forming unit-erythroid and colony-forming unit-erythroid assays showed increased erythroid colony numbers from Emp null livers. Morphologic examination showed that Emp null CFU-E-derived erythroblasts were immature compared to those derived from wild-type CFU-Es, suggesting that loss of Emp function in erythroid cells results in impaired proliferation and terminal differentiation. These results demonstrate that Emp plays a cell intrinsic role in the erythroid lineage.

Human T-cell leukemia virus type 1 Tax oncoprotein represses the expression of the BCL11B tumor suppressor in T-cells

PubMed Central

Takachi, Takayuki; Takahashi, Masahiko; Takahashi-Yoshita, Manami; Higuchi, Masaya; Obata, Miki; Mishima, Yukio; Okuda, Shujiro; Tanaka, Yuetsu; Matsuoka, Masao; Saitoh, Akihiko; Green, Patrick L; Fujii, Masahiro

2015-01-01

Human T-cell leukemia virus type 1 (HTLV-1) is the etiological agent of adult T cell leukemia (ATL), which is an aggressive form of T-cell malignancy. HTLV-1 oncoproteins, Tax and HBZ, play crucial roles in the immortalization of T-cells and/or leukemogenesis by dysregulating the cellular functions in the host. Recent studies show that HTLV-1-infected T-cells have reduced expression of the BCL11B tumor suppressor protein. In the present study, we explored whether Tax and/or HBZ play a role in downregulating BCL11B in HTLV-1-infected T-cells. Lentiviral transduction of Tax in a human T-cell line repressed the expression of BCL11B at both the protein and mRNA levels, whereas the transduction of HBZ had little effect on the expression. Tax mutants with a decreased activity for the NF-κB, CREB or PDZ protein pathways still showed a reduced expression of the BCL11B protein, thereby implicating a different function of Tax in BCL11B downregulation. In addition, the HTLV-2 Tax2 protein reduced the BCL11B protein expression in T-cells. Seven HTLV-1-infected T-cell lines, including three ATL-derived cell lines, showed reduced BCL11B mRNA and protein expression relative to an uninfected T-cell line, and the greatest reductions were in the cells expressing Tax. Collectively, these results indicate that Tax is responsible for suppressing BCL11B protein expression in HTLV-1-infected T-cells; Tax-mediated repression of BCL11B is another mechanism that Tax uses to promote oncogenesis of HTLV-1-infected T-cells. PMID:25613934

Epigenetics: The missing link to understanding β-cell dysfunction in the pathogenesis of type 2 diabetes

PubMed Central

Gilbert, Elizabeth R.; Liu, Dongmin

2012-01-01

Type 2 diabetes (T2D) is a growing health problem worldwide. While peripheral insulin resistance is common during obesity and aging in both animals and people, progression to T2D is largely due to insulin secretory dysfunction and significant apoptosis of functional β-cells, leading to an inability to compensate for insulin resistance. It is recognized that environmental factors and nutrition play an important role in the pathogenesis of diabetes. However, our knowledge surrounding molecular mechanisms by which these factors trigger β-cell dysfunction and diabetes is still limited. Recent discoveries raise the possibility that epigenetic changes in response to environmental stimuli may play an important role in the development of diabetes. In this paper, we review emerging knowledge regarding epigenetic mechanisms that may be involved in β-cell dysfunction and pathogenesis of diabetes, including the role of nutrition, oxidative stress and inflammation. We will mainly focus on the role of DNA methylation and histone modifications but will also briefly review data on miRNA effects on the pancreatic islets. Further studies aimed at better understanding how epigenetic regulation of gene expression controls β-cell function may reveal potential therapeutic targets for prevention and treatment of diabetes. PMID:22810088

Immune Cells from SR/CR Mice Induce the Regression of Established Tumors in BALB/c and C57BL/6 Mice

PubMed Central

Koch, Janne; Hau, Jann; Pravsgaard Christensen, Jan; Elvang Jensen, Henrik; Bagge Hansen, Morten; Rieneck, Klaus

2013-01-01

Few experimental models are available for the study of natural resistance to cancer. One of them is the SR/CR (spontaneous regression/complete resistance) mouse model in which natural resistance to a variety of cancer types appeared to be inherited in SR/CR strains of BALB/c and C57BL/6 mice. The genetic, cellular, and molecular effector mechanisms in this model are largely unknown, but cells from the innate immune system may play a significant role. In contrast to previous observations, the cancer resistance was limited to S180 sarcoma cancer cells. We were unable to confirm previous observations of resistance to EL-4 lymphoma cells and J774A.1 monocyte-macrophage cancer cells. The cancer resistance against S180 sarcoma cells could be transferred to susceptible non-resistant BALB/c mice as well as C57BL/6 mice after depletion of both CD4+/CD8+ leukocytes and B-cells from SR/CR mice. In the responding recipient mice, the cancer disappeared gradually following infiltration of a large number of polymorphonuclear granulocytes and remarkably few lymphocytes in the remaining tumor tissues. This study confirmed that the in vivo growth and spread of cancer cells depend on a complex interplay between the cancer cells and the host organism. Here, hereditary components of the immune system, most likely the innate part, played a crucial role in this interplay and lead to resistance to a single experimental cancer type. The fact that leukocytes depleted of both CD4+/CD8+ and B cells from the cancer resistant donor mice could be transferred to inhibit S180 cancer cell growth in susceptible recipient mice support the vision of an efficient and adverse event free immunotherapy in future selected cancer types. PMID:23555858

A Novel Ras Effector Pathway Found to Play Significant Role in Tumor Suppression | Poster

Cancer.gov

By Nancy Parrish, Staff Writer; photo by Richard Frederickson, Staff Photographer Normal cells have mechanisms to prevent the development of cancer. Among these is a type of tumor suppressor mechanism known as oncogene-induced senescence, or OIS, which halts the uncontrolled growth of cells caused by mutations in oncogenes. The oncogene Ras plays a crucial role in inducing OIS through a specific cascade of proteins, as reported in a recent article in Molecular and Cellular Biology by Jacqueline Salotti, Ph.D., and colleagues in the Eukaryotic Transcriptional Regulation Section of the Mouse Cancer Genetics Program, Center for Cancer Research (CCR).

Changes in cell wall polysaccharide composition, gene transcription and alternative splicing in germinating barley embryos.

PubMed

Zhang, Qisen; Zhang, Xiaoqi; Pettolino, Filomena; Zhou, Gaofeng; Li, Chengdao

2016-02-01

Barley (Hordeum vulgare L.) seed germination initiates many important biological processes such as DNA, membrane and mitochondrial repairs. However, little is known on cell wall modifications in germinating embryos. We have investigated cell wall polysaccharide composition change, gene transcription and alternative splicing events in four barley varieties at 24h and 48 h germination. Cell wall components in germinating barley embryos changed rapidly, with increases in cellulose and (1,3)(1,4)-β-D-glucan (20-100%) within 24h, but decreases in heteroxylan and arabinan (3-50%). There were also significant changes in the levels of type I arabinogalactans and heteromannans. Alternative splicing played very important roles in cell wall modifications. At least 22 cell wall transcripts were detected to undergo either alternative 3' splicing, alternative 5' splicing or intron retention type of alternative splicing. These genes coded enzymes catalyzing synthesis and degradation of cellulose, heteroxylan, (1,3)(1,4)-β-D-glucan and other cell wall polymers. Furthermore, transcriptional regulation also played very important roles in cell wall modifications. Transcript levels of primary wall cellulase synthase, heteroxylan synthesizing and nucleotide sugar inter-conversion genes were very high in germinating embryos. At least 50 cell wall genes changed transcript levels significantly. Expression patterns of many cell wall genes coincided with changes in polysaccharide composition. Our data showed that cell wall polysaccharide metabolism was very active in germinating barley embryos, which was regulated at both transcriptional and post-transcriptional levels. Copyright © 2015 Elsevier GmbH. All rights reserved.

Epithelial and ectomesenchymal role of the type I TGF-β receptor ALK5 during facial morphogenesis and palatal fusion

PubMed Central

Dudas, Marek; Kim, Jieun; Li, Wai-Yee; Nagy, Andre; Larsson, Jonas; Karlsson, Stefan; Chai, Yang; Kaartinen, Vesa

2006-01-01

Transforming growth factor beta (TGF-β) proteins play important roles in morphogenesis of many craniofacial tissues; however, detailed biological mechanisms of TGF-β action, particularly in vivo, are still poorly understood. Here, we deleted the TGF-β type I receptor gene Alk5 specifically in the embryonic ectodermal and neural crest cell lineages. Failure in signaling via this receptor, either in the epithelium or in the mesenchyme, caused severe craniofacial defects including cleft palate. Moreover, the facial phenotypes of neural crest-specific Alk5 mutants included devastating facial cleft and appeared significantly more severe than the defects seen in corresponding mutants lacking the TGF-β type II receptor (TGFβRII), a prototypical binding partner of ALK5. Our data indicate that ALK5 plays unique, non-redundant cell-autonomous roles during facial development. Remarkable divergence between Tgfbr2 and Alk5 phenotypes, together with our biochemical in vitro data, imply that (1) ALK5 mediates signaling of a diverse set of ligands not limited to the three isoforms of TGF-β, and (2) ALK5 acts also in conjunction with type II receptors other than TGFβRII. PMID:16806156

Invariant TAD Boundaries Constrain Cell-Type-Specific Looping Interactions between Promoters and Distal Elements around the CFTR Locus

PubMed Central

Smith, Emily M.; Lajoie, Bryan R.; Jain, Gaurav; Dekker, Job

2016-01-01

Three-dimensional genome structure plays an important role in gene regulation. Globally, chromosomes are organized into active and inactive compartments while, at the gene level, looping interactions connect promoters to regulatory elements. Topologically associating domains (TADs), typically several hundred kilobases in size, form an intermediate level of organization. Major questions include how TADs are formed and how they are related to looping interactions between genes and regulatory elements. Here we performed a focused 5C analysis of a 2.8 Mb chromosome 7 region surrounding CFTR in a panel of cell types. We find that the same TAD boundaries are present in all cell types, indicating that TADs represent a universal chromosome architecture. Furthermore, we find that these TAD boundaries are present irrespective of the expression and looping of genes located between them. In contrast, looping interactions between promoters and regulatory elements are cell-type specific and occur mostly within TADs. This is exemplified by the CFTR promoter that in different cell types interacts with distinct sets of distal cell-type-specific regulatory elements that are all located within the same TAD. Finally, we find that long-range associations between loci located in different TADs are also detected, but these display much lower interaction frequencies than looping interactions within TADs. Interestingly, interactions between TADs are also highly cell-type-specific and often involve loci clustered around TAD boundaries. These data point to key roles of invariant TAD boundaries in constraining as well as mediating cell-type-specific long-range interactions and gene regulation. PMID:26748519

From embryonic stem cells to functioning germ cells: science, clinical and ethical perspectives.

PubMed

Kiatpongsan, Sorapop

2007-10-01

Embryonic stem cells have been well recognized as cells having a versatile potential to differentiate into all types of cells in the body including germ cells. There are many research studies focusing on the differentiation processes and protocols to derive various types of somatic cells from embryonic stem cells. However, germ cells have unique differentiation process and developmental pathway compared with somatic cells. Consequently, they will require different differentiation protocols and special culture techniques. More understanding and established in vitro systems for gametogenesis will greatly contribute to further progression of knowledge and technology in germ cell biology, reproductive biology and reproductive medicine. Moreover if oocytes can be efficiently produced in vitro, this will play an important role on progression in nuclear transfer and nuclear reprogramming technology. The present article will provide concise review on past important discoveries, current ongoing studies and future views of this challenging research area. An ethical perspective has also been proposed to give comprehensive summary and viewpoint for future clinical application.

Voltage-Gated Ion Channels in Cancer Cell Proliferation

PubMed Central

Rao, Vidhya R.; Perez-Neut, Mathew; Kaja, Simon; Gentile, Saverio

2015-01-01

Changes of the electrical charges across the surface cell membrane are absolutely necessary to maintain cellular homeostasis in physiological as well as in pathological conditions. The opening of ion channels alter the charge distribution across the surface membrane as they allow the diffusion of ions such as K+, Ca++, Cl−, Na+. Traditionally, voltage-gated ion channels (VGIC) are known to play fundamental roles in controlling rapid bioelectrical signaling including action potential and/or contraction. However, several investigations have revealed that these classes of proteins can also contribute significantly to cell mitotic biochemical signaling, cell cycle progression, as well as cell volume regulation. All these functions are critically important for cancer cell proliferation. Interestingly, a variety of distinct VGICs are expressed in different cancer cell types, including metastasis but not in the tissues from which these tumors were generated. Given the increasing evidence suggesting that VGIC play a major role in cancer cell biology, in this review we discuss the role of distinct VGIC in cancer cell proliferation and possible therapeutic potential of VIGC pharmacological manipulation. PMID:26010603

Necroptosis in neurodegenerative diseases: a potential therapeutic target

PubMed Central

Zhang, Shuo; Tang, Mi-bo; Luo, Hai-yang; Shi, Chang-he; Xu, Yu-ming

2017-01-01

Neurodegenerative diseases are a group of chronic progressive disorders characterized by neuronal loss. Necroptosis, a recently discovered form of programmed cell death, is a cell death mechanism that has necrosis-like morphological characteristics. Necroptosis activation relies on the receptor-interacting protein (RIP) homology interaction motif (RHIM). A variety of RHIM-containing proteins transduce necroptotic signals from the cell trigger to the cell death mediators RIP3 and mixed lineage kinase domain-like protein (MLKL). RIP1 plays a particularly important and complex role in necroptotic cell death regulation ranging from cell death activation to inhibition, and these functions are often cell type and context dependent. Increasing evidence suggests that necroptosis plays an important role in the pathogenesis of neurodegenerative diseases. Moreover, small molecules such as necrostatin-1 are thought inhibit necroptotic signaling pathway. Understanding the precise mechanisms underlying necroptosis and its interactions with other cell death pathways in neurodegenerative diseases could provide significant therapeutic insights. The present review is aimed at summarizing the molecular mechanisms of necroptosis and highlighting the emerging evidence on necroptosis as a major driver of neuron cell death in neurodegenerative diseases. PMID:28661482

Sensitivity of human cells expressing low-fidelity or weak-catalytic-activity variants of DNA polymerase ζ to genotoxic stresses.

PubMed

Suzuki, Tetsuya; Grúz, Petr; Honma, Masamitsu; Adachi, Noritaka; Nohmi, Takehiko

2016-09-01

Translesion DNA polymerases (TLS pols) play critical roles in defense mechanisms against genotoxic agents. The defects or mutations of TLS pols are predicted to result in hypersensitivity of cells to environmental mutagens. In this study, human cells expressing DNA polymerase ζ (Pol ζ) variants with low fidelity or weak catalytic activity have been established with Nalm-6-MSH+ cells and their sensitivity to mutagenicity and cytotoxicity of benzo[a]pyrene diol epoxide (BPDE) and ultraviolet-C light (UV-C) was examined. The low-fidelity mutants were engineered by knocking-in DNA sequences that direct changes of leucine 2618 to either phenylalanine (L2618F) or methionine (L2618M) of Pol ζ. The weak-catalytic-activity mutants were generated by knocking-in DNA sequences that direct changes of either tyrosine 2779 to phenylalanine (Y2779F) or aspartate 2781 to asparagine (D2781N). In addition, a +1 frameshift mutation, i.e., CCC to CCCC, was introduced in the coding region of the TK1 gene to measure the mutant frequencies. Doubling time and spontaneous TK mutant frequencies of the established cell lines were similar to those of the wild-type cells. The low-fidelity mutants displayed, however, higher sensitivity to the mutagenicity of BPDE and UV-C than the wild-type cells although their cytotoxic sensitivity was not changed. In contrast, the weak-catalytic-activity mutants were more sensitive to the cytotoxicity of BPDE and UV-C than the wild-type cells, and displayed much higher sensitivity to the clastogenicity of BPDE than the wild-type cells in an in vitro micronucleus assay. These results indicate that human Pol ζ is involved in TLS across DNA lesions induced by BPDE and UV-C and also that the TLS plays important roles in induction of mutations, clastogenicity and in cellular survival of the damaged human cells. Similarities and differences in in vivo roles of yeast and human Pol ζ in genome integrity are discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

Chemokines and skin diseases.

PubMed

Sugaya, Makoto

2015-04-01

Chemokines are small molecules that induce chemotaxis and activation of certain subsets of leukocytes. The expression patterns of chemokines and chemokine receptors are specific to certain organs and cells. Therefore, chemokines are important to elucidate the mechanism of organ-specific human diseases. CCL17 expressed by Langerhans cells, blood endothelial cells, and fibroblasts plays a key role in attracting Th2 cells and tumor cells of adult T-cell leukemia/lymphoma and mycosis fungoides/Sézary syndrome into the skin, developing various Th2-type inflammatory skin diseases as well as cutaneous lymphoma. CCL11 and CCL26 expressed by skin-resident cells, such as fibroblasts, blood endothelial cells, and keratinocytes, induce infiltration of CCR3-expressing cells such as Th2 cells and eosinophils. CCL11 may also serve as an autocrine as well as a paracrine in anaplastic large cell lymphoma. CX3CL1 expressed on blood endothelial cells leads to infiltration of CX3CR1(+) immune cells, such as mast cells, neutrophils, and macrophages, playing important roles in wound healing, tumor immunity, and vasculitis. Biologics targeting chemokines and their receptors are promising strategies for various skin diseases that are resistant to the current therapy.

Influence of Helical Cell Shape on Motility of Helicobacter Pylori

NASA Astrophysics Data System (ADS)

Hardcastle, Joseph; Martinez, Laura; Salama, Nina; Bansil, Rama; Boston University Collaboration; University of Washington Collaboration

2014-03-01

Bacteria's body shape plays an important role in motility by effecting chemotaxis, swimming mechanisms, and swimming speed. A prime example of this is the bacteria Helicobacter Pylori;whose helical shape has long been believed to provide an advantage in penetrating the viscous mucus layer protecting the stomach lining, its niche environment. To explore this we have performed bacteria tracking experiments of both wild-type bacteria along with mutants, which have a straight rod shape. A wide distribution of speeds was found. This distribution reflects both a result of temporal variation in speed and different shape morphologies in the bacterial population. Our results show that body shape plays less role in a simple fluid. However, in a more viscous solution the helical shape results in increased swimming speeds. In addition, we use experimentally obtained cell shape measurements to model the hydrodynamic influence of cell shape on swimming speed using resistive force theory. The results agree with the experiment, especially when we fold in the temporal distribution. Interestingly, our results suggest distinct wild-type subpopulations with varying number of half helices can lead to different swimming speeds. NSF PHY

Proteus mirabilis uroepithelial cell adhesin (UCA) fimbria plays a role in the colonization of the urinary tract.

PubMed

Pellegrino, Rafael; Scavone, Paola; Umpiérrez, Ana; Maskell, Duncan J; Zunino, Pablo

2013-03-01

Urinary tract infections (UTIs) are among the most common bacterial infections in humans. Proteus mirabilis is an opportunistic pathogen, capable of causing severe UTIs, with serious kidney damage that may even lead to death. Several virulence factors are involved in the pathogenicity of this bacterium. Among these, adherence to the uroepithelium mediated by fimbriae appears to be a significant bacterial attribute related to urovirulence. Proteus mirabilis expresses several types of fimbriae that could be involved in the pathogenesis of UTI, including uroepithelial cell adhesin (UCA). In this report, we used an uropathogenic P. mirabilis wild-type strain and an isogenic ucaA mutant unable to express UCA to study the pathogenic role of this fimbria in UTI. Ability of the mutant to adhere to desquamated uroepithelial cells and to infect mice using different experimental UTI models was significantly impaired. These results allow us to conclude that P. mirabilis UCA plays an important role in the colonization of the urinary tract. © 2013 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

The ubiquitin ligase Cbl-b limits Pseudomonas aeruginosa exotoxin T-mediated virulence.

PubMed

Balachandran, Priya; Dragone, Leonard; Garrity-Ryan, Lynne; Lemus, Armando; Weiss, Arthur; Engel, Joanne

2007-02-01

Pseudomonas aeruginosa, an important cause of opportunistic infections in humans, delivers bacterial cytotoxins by type III secretion directly into the host cell cytoplasm, resulting in disruption of host cell signaling and host innate immunity. However, little is known about the fate of the toxins themselves following injection into the host cytosol. Here, we show by both in vitro and in vivo studies that the host ubiquitin ligase Cbl-b interacts with the type III-secreted effector exotoxin T (ExoT) and plays a key role in vivo in limiting bacterial dissemination mediated by ExoT. We demonstrate that, following polyubiquitination, ExoT undergoes regulated proteasomal degradation in the host cell cytosol. ExoT interacts with the E3 ubiquitin ligase Cbl-b and Crk, the substrate for the ExoT ADP ribosyltransferase (ADPRT) domain. The efficiency of degradation is dependent upon the activity of the ADPRT domain. In mouse models of acute pneumonia and systemic infection, Cbl-b is specifically required to limit the dissemination of ExoT-producing bacteria whereas c-Cbl plays no detectable role. To the best of our knowledge, this represents the first identification of a mammalian gene product that is specifically required for in vivo resistance to disease mediated by a type III-secreted effector.

The ubiquitin ligase Cbl-b limits Pseudomonas aeruginosa exotoxin T–mediated virulence

PubMed Central

Balachandran, Priya; Dragone, Leonard; Garrity-Ryan, Lynne; Lemus, Armando; Weiss, Arthur; Engel, Joanne

2007-01-01

Pseudomonas aeruginosa, an important cause of opportunistic infections in humans, delivers bacterial cytotoxins by type III secretion directly into the host cell cytoplasm, resulting in disruption of host cell signaling and host innate immunity. However, little is known about the fate of the toxins themselves following injection into the host cytosol. Here, we show by both in vitro and in vivo studies that the host ubiquitin ligase Cbl-b interacts with the type III–secreted effector exotoxin T (ExoT) and plays a key role in vivo in limiting bacterial dissemination mediated by ExoT. We demonstrate that, following polyubiquitination, ExoT undergoes regulated proteasomal degradation in the host cell cytosol. ExoT interacts with the E3 ubiquitin ligase Cbl-b and Crk, the substrate for the ExoT ADP ribosyltransferase (ADPRT) domain. The efficiency of degradation is dependent upon the activity of the ADPRT domain. In mouse models of acute pneumonia and systemic infection, Cbl-b is specifically required to limit the dissemination of ExoT-producing bacteria whereas c-Cbl plays no detectable role. To the best of our knowledge, this represents the first identification of a mammalian gene product that is specifically required for in vivo resistance to disease mediated by a type III–secreted effector. PMID:17235393

Prognostic Indications of Elevated MCT4 and CD147 across Cancer Types: A Meta-Analysis

PubMed Central

Bovenzi, Cory D.; Hamilton, James; Tassone, Patrick; Johnson, Jennifer; Cognetti, David M.; Luginbuhl, Adam; Keane, William M.; Zhan, Tingting; Tuluc, Madalina; Bar-Ad, Voichita; Martinez-Outschoorn, Ubaldo; Curry, Joseph M.

2015-01-01

Background. Metabolism in the tumor microenvironment can play a critical role in tumorigenesis and tumor aggression. Metabolic coupling may occur between tumor compartments; this phenomenon can be prognostically significant and may be conserved across tumor types. Monocarboxylate transporters (MCTs) play an integral role in cellular metabolism via lactate transport and have been implicated in metabolic synergy in tumors. The transporters MCT1 and MCT4 are regulated via expression of their chaperone, CD147. Methods. We conducted a meta-analysis of existing publications on the relationship between MCT1, MCT4, and CD147 expression and overall survival and disease-free survival in cancer, using hazard ratios derived via multivariate Cox regression analyses. Results. Increased MCT4 expressions in the tumor microenvironment, cancer cells, or stromal cells were all associated with decreased overall survival and decreased disease-free survival (p < 0.001 for all analyses). Increased CD147 expression in cancer cells was associated with decreased overall survival and disease-free survival (p < 0.0001 for both analyses). Few studies were available on MCT1 expression; MCT1 expression was not clearly associated with overall or disease-free survival. Conclusion. MCT4 and CD147 expression correlate with worse prognosis across many cancer types. These results warrant further investigation of these associations. PMID:26779534

Stem Cell-Soluble Signals Enhance Multilumen Formation in SMG Cell Clusters.

PubMed

Maruyama, C L M; Leigh, N J; Nelson, J W; McCall, A D; Mellas, R E; Lei, P; Andreadis, S T; Baker, O J

2015-11-01

Saliva plays a major role in maintaining oral health. Patients with salivary hypofunction exhibit difficulty in chewing and swallowing foods, tooth decay, periodontal disease, and microbial infections. At this time, treatments for hyposalivation are limited to medications (e.g., muscarinic receptor agonists: pilocarpine and cevimeline) that induce saliva secretion from residual acinar cells as well as artificial salivary substitutes. Therefore, advancement of restorative treatments is necessary to improve the quality of life in these patients. Our previous studies indicated that salivary cells are able to form polarized 3-dimensional structures when grown on growth factor-reduced Matrigel. This basement membrane is rich in laminin-III (L1), which plays a critical role in salivary gland formation. Mitotically inactive feeder layers have been used previously to support the growth of many different cell types, as they provide factors necessary for cell growth and organization. The goal of this study was to improve salivary gland cell differentiation in primary cultures by using a combination of L1 and a feeder layer of human hair follicle-derived mesenchymal stem cells (hHF-MSCs). Our results indicated that the direct contact of mouse submandibular (mSMG) cell clusters and hHF-MSCs was not required for mSMG cells to form acinar and ductal structures. However, the hHF-MSC conditioned medium enhanced cell organization and multilumen formation, indicating that soluble signals secreted by hHF-MSCs play a role in promoting these features. © International & American Associations for Dental Research 2015.

Interactions between genetic background, insulin resistance and β-cell function.

PubMed

Kahn, S E; Suvag, S; Wright, L A; Utzschneider, K M

2012-10-01

An interaction between genes and the environment is a critical component underlying the pathogenesis of the hyperglycaemia of type 2 diabetes. The development of more sophisticated techniques for studying gene variants and for analysing genetic data has led to the discovery of some 40 genes associated with type 2 diabetes. Most of these genes are related to changes in β-cell function, with a few associated with decreased insulin sensitivity and obesity. Interestingly, using quantitative traits based on continuous measures rather than dichotomous ones, it has become evident that not all genes associated with changes in fasting or post-prandial glucose are also associated with a diagnosis of type 2 diabetes. Identification of these gene variants has provided novel insights into the physiology and pathophysiology of the β-cell, including the identification of molecules involved in β-cell function that were not previously recognized as playing a role in this critical cell. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

Early Detection of Ovarian Cancer by Tumor Epithelium-Targeted Molecular Ultrasound

DTIC Science & Technology

2014-10-01

successful pregnancy outcome. *PIF Proprietary G-12 IL-33-responsive group 2 innate lymphoid cells are present in mouse uterine tissue and may play roles in... innate lymphoid cells (ILC2s) that are responsive to IL-33 drive helminth immunity, type 2 immune responses, and tissue pathology and homeostasis in...16 (IL-16) secreted by immune cells . Inflammation of the ovary and tubal epithelium due to frequent ovulation leads to the development of oxidative

Cell-type-specific modelling of intracellular calcium signalling: a urothelial cell model.

PubMed

Appleby, Peter A; Shabir, Saqib; Southgate, Jennifer; Walker, Dawn

2013-09-06

Calcium signalling plays a central role in regulating a wide variety of cell processes. A number of calcium signalling models exist in the literature that are capable of reproducing a variety of experimentally observed calcium transients. These models have been used to examine in more detail the mechanisms underlying calcium transients, but very rarely has a model been directly linked to a particular cell type and experimentally verified. It is important to show that this can be achieved within the general theoretical framework adopted by these models. Here, we develop a framework designed specifically for modelling cytosolic calcium transients in urothelial cells. Where possible, we draw upon existing calcium signalling models, integrating descriptions of components known to be important in this cell type from a number of studies in the literature. We then add descriptions of several additional pathways that play a specific role in urothelial cell signalling, including an explicit ionic influx term and an active pumping mechanism that drives the cytosolic calcium concentration to a target equilibrium. The resulting one-pool model of endoplasmic reticulum (ER)-dependent calcium signalling relates the cytosolic, extracellular and ER calcium concentrations and can generate a wide range of calcium transients, including spikes, bursts, oscillations and sustained elevations in the cytosolic calcium concentration. Using single-variate robustness and multivariate sensitivity analyses, we quantify how varying each of the parameters of the model leads to changes in key features of the calcium transient, such as initial peak amplitude and the frequency of bursting or spiking, and in the transitions between bursting- and plateau-dominated modes. We also show that, novel to our urothelial cell model, the ionic and purinergic P2Y pathways make distinct contributions to the calcium transient. We then validate the model using human bladder epithelial cells grown in monolayer cell culture and show that the model robustly captures the key features of the experimental data in a way that is not possible using more generic calcium models from the literature.

p21 induction plays a dual role in anti-cancer activity of ursolic acid

PubMed Central

Zhang, Xudong; Song, Xinhua; Yin, Shutao; Zhao, Chong; Fan, Lihong

2015-01-01

Previous studies have shown that induction of G1 arrest and apoptosis by ursolic acid is associated with up-regulation of cyclin-dependent kinase inhibitor (CDKI) protein p21 in multiple types of cancer cells. However, the functional role of p21 induction in G1 cell cycle arrest and apoptosis, and the mechanisms of p21 induction by ursolic acid have not been critically addressed. In the current study, we demonstrated that p21 played a mediator role in G1 cell cycle arrest by ursolic acid, whereas p21-mediated up-regulation of Mcl-1 compromised apoptotic effect of ursolic acid. These results suggest that p21 induction plays a dual role in the anti-cancer activity of ursolic acid in terms of cell cycle and apoptosis regulation. p21 induction by ursolic acid was attributed to p53 transcriptional activation. Moreover, we found that ursolic acid was able to inhibit murine double minute-2 protein (MDM2) and T-LAK cell-originated protein kinase (TOPK), the two negative regulator of p53, which in turn contributed to ursolic acid-induced p53 activation. Our findings provided novel insights into understanding of the mechanisms involved in cell cycle arrest and apoptosis induction in response to ursolic acid exposure. PMID:26582056

Rat globus pallidus neurons: functional classification and effects of dopamine depletion.

PubMed

Karain, Brad; Xu, Dan; Bellone, John A; Hartman, Richard E; Shi, Wei-Xing

2015-01-01

The rat globus pallidus (GP) is homologous to the primate GP externus. Studies with injectable anesthetics suggest that GP neurons can be classified into Type-I and Type-II cells based on extracellularly recorded spike shape, or positively coupled (PC), negatively coupled (NC), and uncoupled (UC) cells based on functional connectivity with the cortex. In this study, we examined the electrophysiology of rat GP neurons using the inhalational anesthetic isoflurane which offers more constant and easily regulated levels of anesthesia than injectable anesthetics. In 130 GP neurons recorded using small-tip glass electrodes (<1 μm), all but one fired Type-II spikes (positive/negative waveform). Type-I cells were unlikely to be inhibited by isoflurane since all GP neurons also fired Type-II spikes under ketamine-induced anesthesia. When recorded with large-tip electrodes (∼2 μm), however, over 70% of GP neurons exhibited Type-I spikes (negative/positive waveform). These results suggest that the spike shape, recorded extracellularly, varies depending on the electrode used and is not reliable in distinguishing Type-I and Type-II neurons. Using dual-site recording, 40% of GP neurons were identified as PC cells, 17.5% NC cells, and 42.5% UC cells. The three subtypes also differed significantly in firing rate and pattern. Lesions of dopamine neurons increased the number of NC cells, decreased that of UC cells, and significantly shifted the phase relationship between PC cells and the cortex. These results support the presence of GP neuron subtypes and suggest that each subtype plays a different role in the pathophysiology of Parkinson's disease. Synapse 69:41-51, 2015. © 2014 Wiley Periodicals, Inc. © 2014 Wiley Periodicals, Inc.

A distinct subset of proinflammatory neutrophils isolated from patients with systemic lupus erythematosus induces vascular damage and synthesizes type I Interferons*

PubMed Central

Denny, Michael F.; Yalavarthi, Srilakshmi; Zhao, Wenpu; Thacker, Seth G.; Anderson, Marc; Sandy, Ashley R.; McCune, W. Joseph; Kaplan, Mariana J.

2010-01-01

Neutrophil-specific genes are abundant in PBMC microarrays from lupus patients due to presence of low density granulocytes (LDGs) in mononuclear cell fractions. The functionality and pathogenicity of these LDGs have not been characterized. We developed a technique to purify LDGs from lupus PBMCs and assessed their phenotype, function and potential role in disease pathogenesis. LDGs, their autologous lupus neutrophils and healthy control neutrophils were compared in their microbicidal and phagocytic capacities, generation of reactive oxygen species, activation status, inflammatory cytokine profile and type I IFN expression and signatures. The capacity of LDGs to kill endothelial cells and their antiangiogenic potential were also assessed. LDGs display an activated phenotype, secrete increased levels of type I IFNs, TNF-α and IFN-γ, but show impaired phagocytic potential. LDGs induce significant endothelial cell cytotoxicity and synthesize sufficient levels of type I IFNs to disrupt the capacity of endothelial progenitor cells to differentiate into mature endothelial cells. Further, LDG depletion restores the functional capacity of endothelial progenitor cells. We conclude that lupus LDGs are proinflammatory and display pathogenic features, including the capacity to synthesize type I IFNs. They may play an important dual role in premature cardiovascular disease development in SLE by simultaneously mediating enhanced vascular damage while inhibiting vascular repair. PMID:20164424

The Role of Bitter and Sweet Taste Receptors in Upper Airway Immunity

PubMed Central

Workman, Alan D.; Palmer, James N.; Adappa, Nithin D.

2016-01-01

Over the past several years, taste receptors have emerged as key players in the regulation of innate immune defenses in the mammalian respiratory tract. Several cell types in the airway, including ciliated epithelial cells, solitary chemosensory cells, and bronchial smooth muscle cells, all display chemoresponsive properties that utilize taste receptors. A variety of bitter products secreted by microbes are detected with resultant downstream inflammation, increased mucous clearance, antimicrobial peptide secretion, and direct bacterial killing. Genetic variation of bitter taste receptors also appears to play a role in the susceptibility to infection in respiratory disease states, including that of chronic rhinosinusitis. Ongoing taste receptor research may yield new therapeutics that harness innate immune defenses in the respiratory tract and may offer alternatives to antibiotic treatment. The present review discusses taste receptor-protective responses and analyzes the role these receptors play in mediating airway immune function. PMID:26492878

Chemical Activation of the Hypoxia-Inducible Factor Reversibly Reduces Tendon Stem Cell Proliferation, Inhibits Their Differentiation, and Maintains Cell Undifferentiation.

PubMed

Menon, Alessandra; Creo, Pasquale; Piccoli, Marco; Bergante, Sonia; Conforti, Erika; Banfi, Giuseppe; Randelli, Pietro; Anastasia, Luigi

2018-01-01

Adult stem cell-based therapeutic approaches for tissue regeneration have been proposed for several years. However, adult stem cells are usually limited in number and difficult to be expanded in vitro, and they usually tend to quickly lose their potency with passages, as they differentiate and become senescent. Culturing stem cells under reduced oxygen tensions (below 21%) has been proposed as a tool to increase cell proliferation, but many studies reported opposite effects. In particular, cell response to hypoxia seems to be very stem cell type specific. Nonetheless, it is clear that a major role in this process is played by the hypoxia inducible factor (HIF), the master regulator of cell response to oxygen deprivation, which affects cell metabolism and differentiation. Herein, we report that a chemical activation of HIF in human tendon stem cells reduces their proliferation and inhibits their differentiation in a reversible and dose-dependent manner. These results support the notion that hypoxia, by activating HIF, plays a crucial role in preserving stem cells in an undifferentiated state in the "hypoxic niches" present in the tissue in which they reside before migrating in more oxygenated areas to heal a damaged tissue.

Systemic localization of seven major types of carbohydrates on cell membranes by dSTORM imaging.

PubMed

Chen, Junling; Gao, Jing; Zhang, Min; Cai, Mingjun; Xu, Haijiao; Jiang, Junguang; Tian, Zhiyuan; Wang, Hongda

2016-07-25

Carbohydrates on the cell surface control intercellular interactions and play a vital role in various physiological processes. However, their systemic distribution patterns are poorly understood. Through the direct stochastic optical reconstruction microscopy (dSTORM) strategy, we systematically revealed that several types of representative carbohydrates are found in clustered states. Interestingly, the results from dual-color dSTORM imaging indicate that these carbohydrate clusters are prone to connect with one another and eventually form conjoined platforms where different functional glycoproteins aggregate (e.g., epidermal growth factor receptor, (EGFR) and band 3 protein). A thorough understanding of the ensemble distribution of carbohydrates on the cell surface paves the way for elucidating the structure-function relationship of cell membranes and the critical roles of carbohydrates in various physiological and pathological cell processes.

Intermediate Filaments Play a Pivotal Role in Regulating Cell Architecture and Function*

PubMed Central

Lowery, Jason; Kuczmarski, Edward R.; Herrmann, Harald; Goldman, Robert D.

2015-01-01

Intermediate filaments (IFs) are composed of one or more members of a large family of cytoskeletal proteins, whose expression is cell- and tissue type-specific. Their importance in regulating the physiological properties of cells is becoming widely recognized in functions ranging from cell motility to signal transduction. IF proteins assemble into nanoscale biopolymers with unique strain-hardening properties that are related to their roles in regulating the mechanical integrity of cells. Furthermore, mutations in the genes encoding IF proteins cause a wide range of human diseases. Due to the number of different types of IF proteins, we have limited this short review to cover structure and function topics mainly related to the simpler homopolymeric IF networks composed of vimentin, and specifically for diseases, the related muscle-specific desmin IF networks. PMID:25957409

Systemic localization of seven major types of carbohydrates on cell membranes by dSTORM imaging

PubMed Central

Chen, Junling; Gao, Jing; Zhang, Min; Cai, Mingjun; Xu, Haijiao; Jiang, Junguang; Tian, Zhiyuan; Wang, Hongda

2016-01-01

Carbohydrates on the cell surface control intercellular interactions and play a vital role in various physiological processes. However, their systemic distribution patterns are poorly understood. Through the direct stochastic optical reconstruction microscopy (dSTORM) strategy, we systematically revealed that several types of representative carbohydrates are found in clustered states. Interestingly, the results from dual-color dSTORM imaging indicate that these carbohydrate clusters are prone to connect with one another and eventually form conjoined platforms where different functional glycoproteins aggregate (e.g., epidermal growth factor receptor, (EGFR) and band 3 protein). A thorough understanding of the ensemble distribution of carbohydrates on the cell surface paves the way for elucidating the structure-function relationship of cell membranes and the critical roles of carbohydrates in various physiological and pathological cell processes. PMID:27453176

Lyapunov exponents and phase diagrams reveal multi-factorial control over TRAIL-induced apoptosis

PubMed Central

Aldridge, Bree B; Gaudet, Suzanne; Lauffenburger, Douglas A; Sorger, Peter K

2011-01-01

Receptor-mediated apoptosis proceeds via two pathways: one requiring only a cascade of initiator and effector caspases (type I behavior) and the second requiring an initiator–effector caspase cascade and mitochondrial outer membrane permeabilization (type II behavior). Here, we investigate factors controlling type I versus II phenotypes by performing Lyapunov exponent analysis of an ODE-based model of cell death. The resulting phase diagrams predict that the ratio of XIAP to pro-caspase-3 concentrations plays a key regulatory role: type I behavior predominates when the ratio is low and type II behavior when the ratio is high. Cell-to-cell variability in phenotype is observed when the ratio is close to the type I versus II boundary. By positioning multiple tumor cell lines on the phase diagram we confirm these predictions. We also extend phase space analysis to mutations affecting the rate of caspase-3 ubiquitylation by XIAP, predicting and showing that such mutations abolish all-or-none control over activation of effector caspases. Thus, phase diagrams derived from Lyapunov exponent analysis represent a means to study multi-factorial control over a complex biochemical pathway. PMID:22108795

Eos is redundant for T regulatory cell function, but plays an important role in IL-2 and Th17 production by CD4+ T conventional cells

PubMed Central

Rieder, Sadiye Amcaoglu; Metidji, Amina; Glass, Deborah Dacek; Thornton, Angela M.; Ikeda, Tohru; Morgan, Bruce A.; Shevach, Ethan M.

2015-01-01

Eos is a transcription factor that belongs to the Ikaros family of transcription factors. Eos has been reported to be a T regulatory cell (Treg) signature gene, to play a critical role in Treg suppressor functions, and to maintain Treg stability. We have utilized mice with a global deficiency of Eos to re-examine the role of Eos expression in both Treg and T conventional (Tconv) cells. Treg from Eos deficient (Eos−/−) mice developed normally, displayed a normal Treg phenotype, and exhibited normal suppressor function in vitro. Eos−/− Treg were as effective as Treg from wild type (WT) mice in suppression of inflammation in a model of inflammatory bowel disease. Bone marrow (BM) from Eos−/− mice was as effective as BM from WT mice in controlling T cell activation when used to reconstitute immunodeficient mice in the presence of Scurfy fetal liver cells. Surprisingly, Eos was expressed in activated Tconv cells and was required for IL-2 production, CD25 expression and proliferation in vitro by CD4+ Tconv cells. Eos−/− mice developed more severe Experimental Autoimmune Encephalomyelitis than WT mice, displayed increased numbers of effector T cells in the periphery and CNS, and amplified IL-17 production. In conclusion, our studies are not consistent with a role for Eos in Treg development and function, but demonstrate that Eos plays an important role in the activation and differentiation of Tconv cells. PMID:26062998

A role for the PDZ-binding domain of the coxsackie B virus and adenovirus receptor (CAR) in cell adhesion and growth.

PubMed

Excoffon, Katherine J D Ashbourne; Hruska-Hageman, Alesia; Klotz, Michael; Traver, Geri L; Zabner, Joseph

2004-09-01

The coxsackie and adenovirus receptor (CAR) plays a role in viral infection, maintenance of the junction adhesion complex in polarized epithelia, and modulation of cellular growth properties. As a viral receptor, the C-terminus appears to play no role indicating that the major function of CAR is to tether the virus to the cell. By contrast, the C-terminus is known to play a role in cellular localization and probably has a significant function in CAR-mediated adhesion and cell growth properties. We hypothesized that the CAR PDZ (PSD-95/Disc-large/ZO-1) binding motif interacts with PDZ-domain-containing proteins to modulate the cellular phenotype. CAR was modified by deleting the last four amino acids (CARDeltaGSIV) and evaluated for cell-cell adhesion in polarized primary human airway epithelia and growth characteristics in stably transfected L-cells. Although ablation of the CAR PDZ-binding motif did not affect adenoviral infection, it did have a significant effect both on cell-cell adhesion and on cell growth. Expression of CARDeltaGSIV failed to increase the transepithelial resistance in polarized epithelia to the same degree as wild-type CAR and failed to act as a growth modulator in L-cells. Furthermore, we provide evidence for three new CAR interacting partners, including MAGI-1b, PICK1 and PSD-95. CAR appears to interact with several distinct PDZ-domain-containing proteins and may exert its biological function through these interactions.

Self-Assembled Superparamagnetic Iron Oxide Nanoclusters for Universal Cell Labeling and MRI

NASA Astrophysics Data System (ADS)

Chen, Shuzhen; Zhang, Jun; Jiang, Shengwei; Lin, Gan; Luo, Bing; Yao, Huan; Lin, Yuchun; He, Chengyong; Liu, Gang; Lin, Zhongning

2016-05-01

Superparamagnetic iron oxide (SPIO) nanoparticles have been widely used in a variety of biomedical applications, especially as contrast agents for magnetic resonance imaging (MRI) and cell labeling. In this study, SPIO nanoparticles were stabilized with amphiphilic low molecular weight polyethylenimine (PEI) in an aqueous phase to form monodispersed nanocomposites with a controlled clustering structure. The iron-based nanoclusters with a size of 115.3 ± 40.23 nm showed excellent performance on cellular uptake and cell labeling in different types of cells, moreover, which could be tracked by MRI with high sensitivity. The SPIO nanoclusters presented negligible cytotoxicity in various types of cells as detected using MTS, LDH, and flow cytometry assays. Significantly, we found that ferritin protein played an essential role in protecting stress from SPIO nanoclusters. Taken together, the self-assembly of SPIO nanoclusters with good magnetic properties provides a safe and efficient method for universal cell labeling with noninvasive MRI monitoring capability.

Identification of small molecule Hes1 modulators as potential anticancer chemotherapeutics.

PubMed

Sail, Vibhavari; Hadden, M Kyle

2013-03-01

Hes1 is a key transcriptional regulator primarily controlled by the Notch signaling pathway, and recent studies have demonstrated both an oncogenic and tumor suppressor role for Hes1, depending on the cell type. Small molecules that activate and inhibit Hes1 activity hold promise as future anticancer chemotherapeutics. We have utilized a cell-based dual luciferase assay to identify modulators of Hes1 expression in a medium-throughput format. A modest screen was performed in HCT-116 colon cancer cell lines, and two small molecules were identified and characterized as Hes1 regulators. Compound 3 induced Hes1 expression and exhibited anticancer effects in pulmonary carcinoid tumor cells, a cell type in which the upregulated Notch/Hes1 signaling plays a tumor suppressive role. Treatment of HCT-116 cells with compound 12 resulted in Hes1 downregulation and antitumor effects. © 2012 John Wiley & Sons A/S.

RNA editing is induced by type I interferon in esophageal squamous cell carcinoma.

PubMed

Zhang, Jinyao; Chen, Zhaoli; Tang, Zefang; Huang, Jianbing; Hu, Xueda; He, Jie

2017-07-01

In recent years, abnormal RNA editing has been shown to play an important role in the development of esophageal squamous cell carcinoma, as such abnormal editing is catalyzed by ADAR (adenosine deaminases acting on RNA). However, the regulatory mechanism of ADAR1 in esophageal squamous cell carcinomas remains largely unknown. In this study, we investigated ADAR1 expression and its association with RNA editing in esophageal squamous cell carcinomas. RNA sequencing applied to esophageal squamous cell carcinoma clinical samples showed that ADAR1 expression was correlated with the expression of STAT1, STAT2, and IRF9. In vitro experiments showed that the abundance of ADAR1 protein was associated with the induced activation of the JAK/STAT pathway by type I interferon. RNA sequencing results showed that treatment with type I interferon caused an increase in the number and degree of RNA editing in esophageal squamous cell carcinoma cell lines. In conclusion, the activation of the JAK/STAT pathway is a regulatory mechanism of ADAR1 expression and causes abnormal RNA editing profile in esophageal squamous cell carcinoma. This mechanism may serve as a new target for esophageal squamous cell carcinoma therapy.

Cell wars: regulation of cell survival and proliferation by cell competition

PubMed Central

Vivarelli, Silvia; Wagstaff, Laura; Piddini, Eugenia

2012-01-01

During cell competition fitter cells take over the tissue at the expense of viable, but less fit, cells, which are eliminated by induction of apoptosis or senescence. This probably acts as a quality-control mechanism to eliminate suboptimal cells and safeguard organ function. Several experimental conditions have been shown to trigger cell competition, including differential levels in ribosomal activity or in signalling pathway activation between cells, although it is unclear how those differences are sensed and translated into fitness levels. Many of the pathways implicated in cell competition have been previously linked with cancer, and this has led to the hypothesis that cell competition could play a role in tumour formation. Cell competition could be co-opted by cancer cells to kill surrounding normal cells and boost their own tissue colonization. However, in some cases, cell competition could have a tumour suppressor role, as cells harbouring mutations in a subset of tumour suppressor genes are killed by wild-type cells. Originally described in developing epithelia, competitive interactions have also been observed in some stem cell niches, where they play a role in regulating stem cell selection, maintenance and tissue repopulation. Thus competitive interactions could be relevant to the maintenance of tissue fitness and have a protective role against aging. PMID:22928509

Regulation of CD4 T cells and their effects on immunopathological inflammation following viral infection.

PubMed

Bhattacharyya, Mitra; Madden, Patrick; Henning, Nathan; Gregory, Shana; Aid, Malika; Martinot, Amanda J; Barouch, Dan H; Penaloza-MacMaster, Pablo

2017-10-01

CD4 T cells help immune responses, but knowledge of how memory CD4 T cells are regulated and how they regulate adaptive immune responses and induce immunopathology is limited. Using adoptive transfer of virus-specific CD4 T cells, we show that naive CD4 T cells undergo substantial expansion following infection, but can induce lethal T helper type 1-driven inflammation. In contrast, memory CD4 T cells exhibit a biased proliferation of T follicular helper cell subsets and were able to improve adaptive immune responses in the context of minimal tissue damage. Our analyses revealed that type I interferon regulates the expansion of primary CD4 T cells, but does not seem to play a critical role in regulating the expansion of secondary CD4 T cells. Strikingly, blockade of type I interferon abrogated lethal inflammation by primary CD4 T cells following viral infection, despite that this treatment increased the numbers of primary CD4 T-cell responses. Altogether, these data demonstrate important aspects of how primary and secondary CD4 T cells are regulated in vivo, and how they contribute to immune protection and immunopathology. These findings are important for rational vaccine design and for improving adoptive T-cell therapies against persistent antigens. © 2017 John Wiley & Sons Ltd.

Growth and differentiation of embryonic stem cells that lack an intact c-fos gene.

PubMed Central

Field, S J; Johnson, R S; Mortensen, R M; Papaioannou, V E; Spiegelman, B M; Greenberg, M E

1992-01-01

The c-fos protooncogene encodes a transcription factor that is thought to play a critical role in proliferation and differentiation as well as in the physiological response of mature cells to their environment. To test directly the role of c-fos in growth and differentiation, we generated mouse embryonic stem cell lines in which both copies of the c-fos gene were specifically disrupted by homologous recombination. Remarkably, the disruption of both copies of c-fos in these cells has no detectable effect on embryonic stem cell viability, growth rate, or differentiation potential. Embryonic stem cells lacking c-fos can differentiate into a wide range of cell types in tissue culture and also in chimeric mice. We conclude that despite a large body of literature suggesting an important role for c-fos in cell growth and differentiation, in at least some cell types this gene is not essential for these processes. Images PMID:1329091

Cell-To-Cell Communication in Bilateral Macronodular Adrenal Hyperplasia Causing Hypercortisolism

PubMed Central

Lefebvre, Hervé; Duparc, Céline; Prévost, Gaëtan; Bertherat, Jérôme; Louiset, Estelle

2015-01-01

It has been well established that, in the human adrenal gland, cortisol secretion is not only controlled by circulating corticotropin but is also influenced by a wide variety of bioactive signals, including conventional neurotransmitters and neuropeptides, released within the cortex by various cell types such as chromaffin cells, neurons, cells of the immune system, adipocytes, and endothelial cells. These different types of cells are present in bilateral macronodular adrenal hyperplasia (BMAH), a rare etiology of primary adrenal Cushing’s syndrome, where they appear intermingled with adrenocortical cells in the hyperplastic cortex. In addition, the genetic events, which cause the disease, favor abnormal adrenal differentiation that results in illicit expression of paracrine regulatory factors and their receptors in adrenocortical cells. All these defects constitute the molecular basis for aberrant autocrine/paracrine regulatory mechanisms, which are likely to play a role in the pathophysiology of BMAH-associated hypercortisolism. The present review summarizes the current knowledge on this topic as well as the therapeutic perspectives offered by this new pathophysiological concept. PMID:25941513

Transglutaminase 2: Friend or foe? The discordant role in neurons and astrocytes.

PubMed

Quinn, Breandan R; Yunes-Medina, Laura; Johnson, Gail V W

2018-03-23

Members of the transglutaminase family catalyze the formation of isopeptide bonds between a polypeptide-bound glutamine and a low molecular weight amine (e.g., spermidine) or the ɛ-amino group of a polypeptide-bound lysine. Transglutaminase 2 (TG2), a prominent member of this family, is unique because in addition to being a transamidating enzyme, it exhibits numerous other activities. As a result, TG2 plays a role in many physiological processes, and its function is highly cell type specific and relies upon a number of factors, including conformation, cellular compartment location, and local concentrations of Ca 2+ and guanine nucleotides. TG2 is the most abundant transglutaminase in the central nervous system (CNS) and plays a pivotal role in the CNS injury response. How TG2 affects the cell in response to an insult is strikingly different in astrocytes and neurons. In neurons, TG2 supports survival. Overexpression of TG2 in primary neurons protects against oxygen and glucose deprivation (OGD)-induced cell death and in vivo results in a reduction in infarct volume subsequent to a stroke. Knockdown of TG2 in primary neurons results in a loss of viability. In contrast, deletion of TG2 from astrocytes results in increased survival following OGD and improved ability to protect neurons from injury. Here, a brief overview of TG2 is provided, followed by a discussion of the role of TG2 in transcriptional regulation, cellular dynamics, and cell death. The differing roles TG2 plays in neurons and astrocytes are highlighted and compared to how TG2 functions in other cell types. © 2018 Wiley Periodicals, Inc.

Ultrastructural characterization of the hemocytes of Lasiodora sp. (Koch, 1850) (Araneae: Theraphosidae).

PubMed

Soares, Tatiana; Cavalcanti, Marília Gabriela Dos Santos; Ferreira, Felipe Roberto Borba; Cavalcanti, Maria do Socorro de Mendonça; Alves, Luiz Carlos; Brayner, Fábio André; Paiva, Patrícia Maria Guedes

2013-05-01

This paper is the first descriptive review of hemolymph cell types in the circulation of the tarantula spider Lasiodora sp. These animals are more long-lived than other arthropods, and may live for approximately twenty years. Such remarkable longevity may result from a highly successful immune system, which in turn is directly correlated with hemocyte function. Since the literature on the genus Lasiodora sp. is limited, the main goal of the present study was to identify the different cell types by optical and transmission microscope. Six hemocyte types were characterized and called prohemocyte, granulocyte type I, granulocyte type II, spherulocyte, oenocytoid and plasmatocyte. Prohemocytes presented a large nucleus, elongated granulocytes type I showed the nucleus with the same cell format, elliptical granulocytes type II showed the central nucleus of identical shape, spherulocytes exhibited the nucleus filling almost the whole cell, oval oenocytoids showed eccentric nucleus and less dense cytoplasm, and irregular plasmatocytes showed a nucleus and no granules in cytoplasm. These polymorphic granulocytes presented a round, elongated, elliptical, oval or irregular profile with large and varied numbers of granules, except for plasmatocytes, that were agranular. Different densities and different concentrations of these granules were found at the periphery of the cell. The possible reasons and implications of differences and similarities between arthropods hemocytes are discussed. It can be concluded that there are six cell types in Lasiodora sp. This study is of the first step in the elucidation of the role these cells play in the circulatory and immune system in spiders. Copyright © 2013 Elsevier Ltd. All rights reserved.

Partial pneumonectomy of telomerase null mice carrying shortened telomeres initiates cell growth arrest resulting in a limited compensatory growth response

PubMed Central

Jackson, Sha-Ron; Lee, Jooeun; Reddy, Raghava; Williams, Genevieve N.; Kikuchi, Alexander; Freiberg, Yael; Warburton, David

2011-01-01

Telomerase mutations and significantly shortened chromosomal telomeres have recently been implicated in human lung pathologies. Natural telomere shortening is an inevitable consequence of aging, which is also a risk factor for development of lung disease. However, the impact of shortened telomeres and telomerase dysfunction on the ability of lung cells to respond to significant challenge is still largely unknown. We have previously shown that lungs of late generation, telomerase null B6.Cg-Terctm1Rdp mice feature alveolar simplification and chronic stress signaling at baseline, a phenocopy of aged lung. To determine the role telomerase plays when the lung is challenged, B6.Cg-Terctm1Rdp mice carrying shortened telomeres and wild-type controls were subjected to partial pneumonectomy. We found that telomerase activity was strongly induced in alveolar epithelial type 2 cells (AEC2) of the remaining lung immediately following surgery. Eighty-six percent of wild-type animals survived the procedure and exhibited a burst of early compensatory growth marked by upregulation of proliferation, stress response, and DNA repair pathways in AEC2. In B6.Cg-Terctm1Rdp mice carrying shortened telomeres, response to pneumonectomy was characterized by decreased survival, diminished compensatory lung growth, attenuated distal lung progenitor cell response, persistent DNA damage, and cell growth arrest. Overall, survival correlated strongly with telomere length. We conclude that functional telomerase and properly maintained telomeres play key roles in both long-term survival and the early phase of compensatory lung growth following partial pneumonectomy. PMID:21460122

Tolerance to the Intestinal Microbiota Mediated by ROR(γt)(+) Cells.

PubMed

Ohnmacht, Caspar

2016-07-01

Harmless microbes colonizing the gut require the establishment of a well-equilibrated symbiosis between this microbiota and its host. However, the immune system is primed to recognize both conserved microbial patterns and foreign antigens, and therefore developed strong tolerance mechanisms to prevent potential fatal immune reactivity to symbiotic microbes. The transcription factor RAR-related orphan-like γt [ROR(γt); encoded by Rorc] plays a key role in the gut for lymphoid tissue organogenesis, development of innate lymphoid cells type 3 (ILC3s) and proinflammatory type 17 T helper (Th17) cells. Surprisingly, recent research has revealed a contribution of ROR(γt)-expressing cells in a variety of tolerance mechanisms in both the innate and adaptive immune system. Copyright © 2016 Elsevier Ltd. All rights reserved.

Involvement of viral envelope GP2 in Ebola virus entry into cells expressing the macrophage galactose-type C-type lectin

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

Usami, Katsuaki; Matsuno, Keita; Igarashi, Manabu

2011-04-01

Highlights: {yields} Ebola virus infection is mediated by binding to and fusion with the target cells. {yields} Structural feature of the viral glycoprotein determines the infectivity. {yields} Surface C-type lectin, MGL, of macrophages and dendritic cells mediate the infection. {yields} GP2, one of glycoprotein subunits, plays an essential role in MGL-mediated infection. {yields} There is a critical amino acid residue involved in high infectivity. -- Abstract: Ebola virus (EBOV) infection is initiated by the interaction of the viral surface envelope glycoprotein (GP) with the binding sites on target cells. Differences in the mortality among different species of the Ebola viruses,more » i.e., Zaire ebolavirus (ZEBOV) and Reston ebolavirus (REBOV), correspond to the in vitro infectivity of the pseudo-typed virus constructed with the GPs in cells expressing macrophage galactose-type calcium-type lectin (MGL/CD301). Through mutagenesis of GP2, the transmembrane-anchored subunit of GP, we found that residues 502-527 of the GP2 sequence determined the different infectivity between VSV-ZEBOV GP and -REBOV GP in MGL/CD301-expressing cells and a histidine residue at position 516 of ZEBOV GP2 appeared essential in the differential infectivity. These findings may provide a clue to clarify a molecular basis of different pathogenicity among EBOV species.« less

Type I interferon promotes alveolar epithelial type II cell survival during pulmonary Streptococcus pneumoniae infection and sterile lung injury in mice.

PubMed

Maier, Barbara B; Hladik, Anastasiya; Lakovits, Karin; Korosec, Ana; Martins, Rui; Kral, Julia B; Mesteri, Ildiko; Strobl, Birgit; Müller, Mathias; Kalinke, Ulrich; Merad, Miriam; Knapp, Sylvia

2016-09-01

Protecting the integrity of the lung epithelial barrier is essential to ensure respiration and proper oxygenation in patients suffering from various types of lung inflammation. Type I interferon (IFN-I) has been associated with pulmonary epithelial barrier function, however, the mechanisms and involved cell types remain unknown. We aimed to investigate the importance of IFN-I with respect to its epithelial barrier strengthening function to better understand immune-modulating effects in the lung with potential medical implications. Using a mouse model of pneumococcal pneumonia, we revealed that IFN-I selectively protects alveolar epithelial type II cells (AECII) from inflammation-induced cell death. Mechanistically, signaling via the IFN-I receptor on AECII is sufficient to promote AECII survival. The net effects of IFN-I are barrier protection, together with diminished tissue damage, inflammation, and bacterial loads. Importantly, we found that the protective role of IFN-I can also apply to sterile acute lung injury, in which loss of IFN-I signaling leads to a significant reduction in barrier function caused by AECII cell death. Our data suggest that IFN-I is an important mediator in lung inflammation that plays a protective role by antagonizing inflammation-associated cell obstruction, thereby strengthening the integrity of the epithelial barrier. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

TSLP: A Key Regulator of Asthma Pathogenesis.

PubMed

West, Erin E; Kashyap, Mohit; Leonard, Warren J

2012-12-01

Asthma is a complex disorder of the airways that is characterized by T helper type 2 (Th2) inflammation. The pleiotrophic cytokine TSLP has emerged as an important player involved in orchestrating the inflammation seen in asthma and other atopic diseases. Early research elucidated the role of TSLP on CD4 + T cells, and recent work has revealed the impact of TSLP on multiple cell types. Furthermore, TSLP plays an important role in the sequential progression of atopic dermatitis to asthma, clarifying the key role of TSLP in the pathogenesis of asthma, a finding with therapeutic implications.

A Maze Game on Android Using Growing Tree Method

NASA Astrophysics Data System (ADS)

Hendrawan, Y. F.

2018-01-01

A maze is a type of puzzle games where a player moves in complex and branched passages to find a particular target or location. One method to create a maze is the Growing Tree method. The method creates a tree that has branches which are the paths of a maze. This research explored three types of Growing Tree method implementations for maze generation on Android mobile devices. The layouts produced could be played in first and third-person perspectives. The experiment results showed that it took 17.3 seconds on average to generate 20 cells x 20 cells dynamic maze layouts.

Correlated waves of actin filaments and PIP3 in Dictyostelium cells.

PubMed

Asano, Yukako; Nagasaki, Akira; Uyeda, Taro Q P

2008-12-01

Chemotaxis-deficient amiB-null mutant Dictyostelium cells show two distinct movements: (1) they extend protrusions randomly without net displacements; (2) they migrate persistently and unidirectionally in a keratocyte-like manner. Here, we monitored the intracellular distribution of phosphatidylinositol (3,4,5)-trisphosphate (PIP(3)) to gain insight into roles PIP(3) plays in those spontaneous motilities. In keratocyte-like cells, PIP(3) showed convex distribution over the basal membrane, with no anterior enrichment. In stalled cells, as well as in wild type cells, PIP(3) repeated wave-like changes, including emergence, expansion and disappearance, on the basal membrane. The waves induced lamellipodia when they approached the cell edge, and the advancing speed of the waves was comparable to the migration speed of the keratocyte-like cells. LY294002, an inhibitor of PI3 kinase, abolished PIP(3) waves in stalled cells and stopped keratocyte-like cells. These results together suggested that keratocyte-like cells are "surfing" on the PIP(3) waves by coupling steady lamellipodial protrusions to the PIP(3) waves. Simultaneous live observation of actin filaments and PIP(3) in wild type or stalled amiB(-) cells indicated that the PIP(3) waves were correlated with wave-like distributions of actin filaments. Most notably, PIP(3) waves often followed actin waves, suggesting that PIP(3) induces local depolymerization of actin filaments. Consistent with this idea, cortical accumulation of PIP(3) was often correlated with local retraction of the periphery. We propose that the waves of PIP(3) and actin filaments are loosely coupled with each other and play important roles in generating spontaneous cell polarity. Copyright 2008 Wiley-Liss, Inc.

MET signalling in primary colon epithelial cells leads to increased transformation irrespective of aberrant Wnt signalling

PubMed Central

Boon, E M J; Kovarikova, M; Derksen, P W B; van der Neut, R

2005-01-01

It has been shown that in hereditary and most sporadic colon tumours, components of the Wnt pathway are mutated. The Wnt target MET has been implicated in the development of colon cancer. Here, we show that overexpression of wild-type or a constitutively activated form of MET in colon epithelial cells leads to increased transformation irrespective of Wnt signalling. Fetal human colon epithelial cells without aberrant Wnt signalling were transfected with wild-type or mutated MET constructs. Expression of these constructs leads to increased phosphorylation of MET and its downstream targets PKB and MAPK. Upon stimulation with HGF, the expression of E-cadherin is downregulated in wild-type MET-transfected cells, whereas cells expressing mutated MET show low E-cadherin levels independent of stimulation with ligand. This implies a higher migratory propensity of these cells. Furthermore, fetal human colon epithelial cells expressing the mutated form of MET have colony-forming capacity in soft agar, while cells expressing wild-type MET show an intermediate phenotype. Subcutaneous injection of mutated MET-transfected cells in nude mice leads to the formation of tumours within 12 days in all mice injected. At this time point, mock-transfected cells do not form tumours, while wild-type MET-transfected cells form subcutaneous tumours in one out of five mice. We thus show that MET signalling can lead to increased transformation of colon epithelial cells independent of Wnt signalling and in this way could play an essential role in the onset and progression of colorectal cancer. PMID:15785735

Thyroid Hormone Induces Apoptosis in Primary Cell Cultures of Tadpole Intestine: Cell Type Specificity and Effects of Extracellular Matrix

PubMed Central

Su, Yuan; Shi, Yufang; Stolow, Melissa A.; Shi, Yun-Bo

1997-01-01

Thyroid hormone (T3 or 3,5,3′-triiodothyronine) plays a causative role during amphibian metamorphosis. To investigate how T3 induces some cells to die and others to proliferate and differentiate during this process, we have chosen the model system of intestinal remodeling, which involves apoptotic degeneration of larval epithelial cells and proliferation and differentiation of other cells, such as the fibroblasts and adult epithelial cells, to form the adult intestine. We have established in vitro culture conditions for intestinal epithelial cells and fibroblasts. With this system, we show that T3 can enhance the proliferation of both cell types. However, T3 also concurrently induces larval epithelial apoptosis, which can be inhibited by the extracellular matrix (ECM). Our studies with known inhibitors of mammalian cell death reveal both similarities and differences between amphibian and mammalian cell death. These, together with gene expression analysis, reveal that T3 appears to simultaneously induce different pathways that lead to specific gene regulation, proliferation, and apoptotic degeneration of the epithelial cells. Thus, our data provide an important molecular and cellular basis for the differential responses of different cell types to the endogenous T3 during metamorphosis and support a role of ECM during frog metamorphosis. PMID:9396758

Sugar homeostasis mediated by cell wall invertase GRAIN INCOMPLETE FILLING 1 (GIF1) plays a role in pre-existing and induced defence in rice.

PubMed

Sun, Li; Yang, Dong-lei; Kong, Yu; Chen, Ying; Li, Xiao-Zun; Zeng, Long-Jun; Li, Qun; Wang, Er-Tao; He, Zu-Hua

2014-02-01

Sugar metabolism and sugar signalling are not only critical for plant growth and development, but are also important for stress responses. However, how sugar homeostasis is involved in plant defence against pathogen attack in the model crop rice remains largely unknown. In this study, we observed that the grains of gif1, a loss-of-function mutant of the cell wall invertase gene GRAIN INCOMPLETE FILLING 1 (GIF1), were hypersusceptible to postharvest fungal pathogens, with decreased levels of sugars and a thinner glume cell wall in comparison with the wild-type. Interestingly, constitutive expression of GIF1 enhanced resistance to both the rice bacterial pathogen Xanthomonas oryzae pv. oryzae and the fungal pathogen Magnaporthe oryzae. The GIF1-overexpressing (GIF1-OE) plants accumulated higher levels of glucose, fructose and sucrose compared with the wild-type plants. More importantly, higher levels of callose were deposited in GIF1-OE plants during pathogen infection. Moreover, the cell wall was much thicker in the infection sites of the GIF1-OE plants when compared with the wild-type plants. We also found that defence-related genes were constitutively activated in the GIF1-OE plants. Taken together, our study reveals that sugar homeostasis mediated by GIF1 plays an important role in constitutive and induced physical and chemical defence. © 2013 BSPP AND JOHN WILEY & SONS LTD.

Formation of reactive oxygen species in lung alveolar cells: effect of vitamin E deficiency.

PubMed

Sabat, Robert; Guthmann, Florian; Rüstow, Bernd

2008-01-01

Reactive oxygen species (ROS) play an important role in the pathogenesis of numerous pulmonary diseases. Various mainly membrane-bound ROS-generating processes exist in alveolar cells. Vitamin E (vit. E) is the most important lipophilic antioxidant. However, the significance of vit. E levels in alveolar cells for the regulation of ROS generation has not been investigated so far. We demonstrated here that feeding rats with vit. E-depleted nourishment for 5 weeks reduced the concentration of vit. E in alveolar type II cell preparations to one-fifth the amount of control animals. This reduction of vit. E levels was associated with an approximately threefold increase in ROS generation in type II pneumocytes, lymphocytes, and macrophages. The contribution of individual processes of ROS formation in control animals differed strongly among these three cell types. However, vit. E deficiency induced predominantly nonmitochondrial ROS formation in alveolar cells. Expression and NAD(P)H-oxidase activity in alveolar type II cell preparations was not affected by vit. E deficiency. Moreover, protein kinase C (PKC) also did not seem to be responsible for vit. E deficiency-induced ROS generation in alveolar cells. Alimentary vit. E supplementation for 2 days corrected the cellular vit. E concentration but failed to normalize ROS generation in alveolar cells. These data let us assume that alimentary vit. E deficiency caused a preferentially nonmitochondria-mediated increase of ROS formation in type II pneumocytes, macrophages, and lymphocytes. However, the short-term supplementation of vit. E does not reverse these effects.

Native structure of a type IV secretion system core complex essential for Legionella pathogenesis.

PubMed

Kubori, Tomoko; Koike, Masafumi; Bui, Xuan Thanh; Higaki, Saori; Aizawa, Shin-Ichi; Nagai, Hiroki

2014-08-12

Bacterial type IV secretion systems are evolutionarily related to conjugation systems and play a pivotal role in infection by delivering numerous virulence factors into host cells. Using transmission electron microscopy, we report the native molecular structure of the core complex of the Dot/Icm type IV secretion system encoded by Legionella pneumophila, an intracellular human pathogen. The biochemically isolated core complex, composed of at least five proteins--DotC, DotD, DotF, DotG, and DotH--has a ring-shaped structure. Intriguingly, morphologically distinct premature complexes are formed in the absence of DotG or DotF. Our data suggest that DotG forms a central channel spanning inner and outer membranes. DotF, a component dispensable for type IV secretion, plays a role in efficient embedment of DotG into the functional core complex. These results highlight a common scheme for the biogenesis of transport machinery.

Ralstonia solanacearum Type III Effector RipAY Is a Glutathione-Degrading Enzyme That Is Activated by Plant Cytosolic Thioredoxins and Suppresses Plant Immunity.

PubMed

Mukaihara, Takafumi; Hatanaka, Tadashi; Nakano, Masahito; Oda, Kenji

2016-04-12

The plant pathogen Ralstonia solanacearum uses a large repertoire of type III effector proteins to succeed in infection. To clarify the function of effector proteins in host eukaryote cells, we expressed effectors in yeast cells and identified seven effector proteins that interfere with yeast growth. One of the effector proteins, RipAY, was found to share homology with the ChaC family proteins that function as γ-glutamyl cyclotransferases, which degrade glutathione (GSH), a tripeptide that plays important roles in the plant immune system. RipAY significantly inhibited yeast growth and simultaneously induced rapid GSH depletion when expressed in yeast cells. The in vitro GSH degradation activity of RipAY is specifically activated by eukaryotic factors in the yeast and plant extracts. Biochemical purification of the yeast protein identified that RipAY is activated by thioredoxin TRX2. On the other hand, RipAY was not activated by bacterial thioredoxins. Interestingly, RipAY was activated by plant h-type thioredoxins that exist in large amounts in the plant cytosol, but not by chloroplastic m-, f-, x-, y- and z-type thioredoxins, in a thiol-independent manner. The transient expression of RipAY decreased the GSH level in plant cells and affected the flg22-triggered production of reactive oxygen species (ROS) and expression of pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) marker genes in Nicotiana benthamiana leaves. These results indicate that RipAY is activated by host cytosolic thioredoxins and degrades GSH specifically in plant cells to suppress plant immunity. Ralstonia solanacearum is the causal agent of bacterial wilt disease of plants. This pathogen injects virulence effector proteins into host cells to suppress disease resistance responses of plants. In this article, we report a biochemical activity of R. solanacearum effector protein RipAY. RipAY can degrade GSH, a tripeptide that plays important roles in the plant immune system, with its γ-glutamyl cyclotransferase activity. The high GSH degradation activity of RipAY is considered to be a good weapon for this bacterium to suppress plant immunity. However, GSH also plays important roles in bacterial tolerance to various stresses and growth. Interestingly, RipAY has an excellent safety mechanism to prevent unwanted firing of its enzyme activity in bacterial cells because RipAY is specifically activated by host eukaryotic thioredoxins. This study also reveals a novel host plant protein acting as a molecular switch for effector activation. Copyright © 2016 Mukaihara et al.

Invariant TAD Boundaries Constrain Cell-Type-Specific Looping Interactions between Promoters and Distal Elements around the CFTR Locus.

PubMed

Smith, Emily M; Lajoie, Bryan R; Jain, Gaurav; Dekker, Job

2016-01-07

Three-dimensional genome structure plays an important role in gene regulation. Globally, chromosomes are organized into active and inactive compartments while, at the gene level, looping interactions connect promoters to regulatory elements. Topologically associating domains (TADs), typically several hundred kilobases in size, form an intermediate level of organization. Major questions include how TADs are formed and how they are related to looping interactions between genes and regulatory elements. Here we performed a focused 5C analysis of a 2.8 Mb chromosome 7 region surrounding CFTR in a panel of cell types. We find that the same TAD boundaries are present in all cell types, indicating that TADs represent a universal chromosome architecture. Furthermore, we find that these TAD boundaries are present irrespective of the expression and looping of genes located between them. In contrast, looping interactions between promoters and regulatory elements are cell-type specific and occur mostly within TADs. This is exemplified by the CFTR promoter that in different cell types interacts with distinct sets of distal cell-type-specific regulatory elements that are all located within the same TAD. Finally, we find that long-range associations between loci located in different TADs are also detected, but these display much lower interaction frequencies than looping interactions within TADs. Interestingly, interactions between TADs are also highly cell-type-specific and often involve loci clustered around TAD boundaries. These data point to key roles of invariant TAD boundaries in constraining as well as mediating cell-type-specific long-range interactions and gene regulation. Copyright © 2016 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Eosinophils may play regionally disparate roles in influencing IgA(+) plasma cell numbers during large and small intestinal inflammation.

PubMed

Forman, Ruth; Bramhall, Michael; Logunova, Larisa; Svensson-Frej, Marcus; Cruickshank, Sheena M; Else, Kathryn J

2016-05-31

Eosinophils are innate immune cells present in the intestine during steady state conditions. An intestinal eosinophilia is a hallmark of many infections and an accumulation of eosinophils is also observed in the intestine during inflammatory disorders. Classically the function of eosinophils has been associated with tissue destruction, due to the release of cytotoxic granule contents. However, recent evidence has demonstrated that the eosinophil plays a more diverse role in the immune system than previously acknowledged, including shaping adaptive immune responses and providing plasma cell survival factors during the steady state. Importantly, it is known that there are regional differences in the underlying immunology of the small and large intestine, but whether there are differences in context of the intestinal eosinophil in the steady state or inflammation is not known. Our data demonstrates that there are fewer IgA(+) plasma cells in the small intestine of eosinophil-deficient ΔdblGATA-1 mice compared to eosinophil-sufficient wild-type mice, with the difference becoming significant post-infection with Toxoplasma gondii. Remarkably, and in complete contrast, the absence of eosinophils in the inflamed large intestine does not impact on IgA(+) cell numbers during steady state, and is associated with a significant increase in IgA(+) cells post-infection with Trichuris muris compared to wild-type mice. Thus, the intestinal eosinophil appears to be less important in sustaining the IgA(+) cell pool in the large intestine compared to the small intestine, and in fact, our data suggests eosinophils play an inhibitory role. The dichotomy in the influence of the eosinophil over small and large intestinal IgA(+) cells did not depend on differences in plasma cell growth factors, recruitment potential or proliferation within the different regions of the gastrointestinal tract (GIT). We demonstrate for the first time that there are regional differences in the requirement of eosinophils for maintaining IgA+ cells between the large and small intestine, which are more pronounced during inflammation. This is an important step towards further delineation of the enigmatic functions of gut-resident eosinophils.

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

Evolutionary insights into T-type Ca2+ channel structure, function, and ion selectivity from the Trichoplax adhaerens homologue

PubMed Central

Smith, Carolyn L.; Abdallah, Salsabil; Le, Phuong; Harracksingh, Alicia N.; Artinian, Liana; Tamvacakis, Arianna N.; Rehder, Vincent; Reese, Thomas S.

2017-01-01

Four-domain voltage-gated Ca2+ (Cav) channels play fundamental roles in the nervous system, but little is known about when or how their unique properties and cellular roles evolved. Of the three types of metazoan Cav channels, Cav1 (L-type), Cav2 (P/Q-, N- and R-type) and Cav3 (T-type), Cav3 channels are optimized for regulating cellular excitability because of their fast kinetics and low activation voltages. These same properties permit Cav3 channels to drive low-threshold exocytosis in select neurons and neurosecretory cells. Here, we characterize the single T-type calcium channel from Trichoplax adhaerens (TCav3), an early diverging animal that lacks muscle, neurons, and synapses. Co-immunolocalization using antibodies against TCav3 and neurosecretory cell marker complexin labeled gland cells, which are hypothesized to play roles in paracrine signaling. Cloning and in vitro expression of TCav3 reveals that, despite roughly 600 million years of divergence from other T-type channels, it bears the defining structural and biophysical features of the Cav3 family. We also characterize the channel’s cation permeation properties and find that its pore is less selective for Ca2+ over Na+ compared with the human homologue Cav3.1, yet it exhibits a similar potent block of inward Na+ current by low external Ca2+ concentrations (i.e., the Ca2+ block effect). A comparison of the permeability features of TCav3 with other cloned channels suggests that Ca2+ block is a locus of evolutionary change in T-type channel cation permeation properties and that mammalian channels distinguish themselves from invertebrate ones by bearing both stronger Ca2+ block and higher Ca2+ selectivity. TCav3 is the most divergent metazoan T-type calcium channel and thus provides an evolutionary perspective on Cav3 channel structure–function properties, ion selectivity, and cellular physiology. PMID:28330839

Antigenic modulation limits the efficacy of anti-CD20 antibodies: implications for antibody selection.

PubMed

Beers, Stephen A; French, Ruth R; Chan, H T Claude; Lim, Sean H; Jarrett, Timothy C; Vidal, Regina Mora; Wijayaweera, Sahan S; Dixon, Sandra V; Kim, Hyungjin; Cox, Kerry L; Kerr, Jonathan P; Johnston, David A; Johnson, Peter W M; Verbeek, J Sjef; Glennie, Martin J; Cragg, Mark S

2010-06-24

Rituximab, a monoclonal antibody that targets CD20 on B cells, is now central to the treatment of a variety of malignant and autoimmune disorders. Despite this success, a substantial proportion of B-cell lymphomas are unresponsive or develop resistance, hence more potent anti-CD20 monoclonal antibodies (mAbs) are continuously being sought. Here we demonstrate that type II (tositumomab-like) anti-CD20 mAbs are 5 times more potent than type I (rituximab-like) reagents in depleting human CD20 Tg B cells, despite both operating exclusively via activatory Fcgamma receptor-expressing macrophages. Much of this disparity in performance is attributable to type I mAb-mediated internalization of CD20 by B cells, leading to reduced macrophage recruitment and the degradation of CD20/mAb complexes, shortening mAb half-life. Importantly, human B cells from healthy donors and most cases of chronic lymphatic leukemia and mantle cell lymphoma, showed rapid CD20 internalization that paralleled that seen in the Tg mouse B cells, whereas most follicular lymphoma and diffuse large B-cell lymphoma cells were far more resistant to CD20 loss. We postulate that differences in CD20 modulation may play a central role in determining the relative efficacy of rituximab in treating these diseases and strengthen the case for focusing on type II anti-CD20 mAb in the clinic.

Exosomes in cancer: small vesicular transporters for cancer progression and metastasis, biomarkers in cancer therapeutics

PubMed Central

Abhari, Alireza; Rahimzadeh, Sevda

2018-01-01

Cancer progression is a polygenic procedure in which the exosomes can function as substantial roles. Exosomes are tiny, phospholipid bilayer membrane nanovesicles of endocytic derivation with a diameter of 40–100 nm. These nanovesicles can transport bioactive molecules containing mRNAs, proteins, DNA fragments, and non-coding RNAs from a donor cell to recipient cells, and cause the alteration in genetic and epigenetic factors and reprogramming of the target cells. Many diverse cell types such as mesenchymal cells, immune cells, and cancer cells can induce the release of exosomes. Increasing evidence illustrated that the exosomes derived from tumor cells might trigger the tumor initiation, tumor cell growth and progression, metastasis, and drug resistance. The secreted nanovesicles of exosomes can play significant roles in cells communicate via shuttling the nucleic acid molecules and proteins to target cells and tissues. In this review, we discussed multiple mechanisms related to biogenesis, load, and shuttle of the exosomes. Also, we illustrated the diverse roles of exosomes in several types of human cancer development, tumor immunology, angiogenesis, and metastasis. The exosomes may act as the promising biomarkers for the prognosis of various types of cancers which suggested a new pathway for anti-tumor therapeutic of these nanovesicles and promoted exosome-based cancer for clinical diagnostic and remedial procedures. PMID:29868251

Expression of synaptogyrin-1 in T1R2-expressing type II taste cells and type III taste cells of rat circumvallate taste buds.

PubMed

Kotani, Takeshi; Toyono, Takashi; Seta, Yuji; Kitou, Ayae; Kataoka, Shinji; Toyoshima, Kuniaki

2013-09-01

Synaptogyrins are conserved components of the exocytic apparatus and function as regulators of Ca(2+)-dependent exocytosis. The synaptogyrin family comprises three isoforms: two neuronal (synaptogyrin-1 and -3) and one ubiquitous (synaptogyrin-2) form. Although the expression patterns of the exocytic proteins synaptotagmin-1, SNAP-25, synaptobrevin-2 and synaptophysin have been elucidated in taste buds, the function and expression pattern of synaptogyrin-1 in rat gustatory tissues have not been determined. Therefore, we examined the expression patterns of synaptogyrin-1 and several cell-specific markers of type II and III cells in rat gustatory tissues. Reverse transcription/polymerase chain reaction assays and immunoblot analysis revealed the expression of synaptogyrin-1 mRNA and its protein in circumvallate papillae. In fungiform, foliate and circumvallate papillae, the antibody against synaptogyrin-1 immunolabeled a subset of taste bud cells and intra- and subgemmal nerve processes. Double-labeling experiments revealed the expression of synaptogyrin-1 in most taste cells immunoreactive for aromatic L-amino acid decarboxylase and the neural cell adhesion molecule. A subset of synaptogyrin-1-immunoreactive taste cells also expressed phospholipase Cβ2, gustducin, or sweet taste receptor (T1R2). In addition, most synaptogyrin-1-immunoreactive taste cells expressed synaptobrevin-2. These results suggest that synaptogyrin-1 plays a regulatory role in transmission at the synapses of type III cells and is involved in exocytic function with synaptobrevin-2 in a subset of type II cells in rat taste buds.

Targeted Deletion and Lipidomic Analysis Identify Epithelial Cell COX-2 as a Major Driver of Chemically-induced Skin Cancer

PubMed Central

Jiao, Jing; Ishikawa, Tomo-o; Dumlao, Darren S.; Norris, Paul C.; Magyar, Clara E.; Mikulec, Carol; Catapang, Art; Dennis, Edward A.; Fischer, Susan M.; Herschman, Harvey R.

2014-01-01

Pharmacologic and global gene deletion studies demonstrate that cyclooxygenase-2 (PTGS2/COX2) plays a critical role in DMBA/TPA-induced skin tumor induction. While many cell types in the tumor microenvironment express COX-2, the cell types in which COX-2 expression is required for tumor promotion are not clearly established. Here, cell-type specific Cox-2 gene deletion reveals a vital role for skin epithelial cell COX-2 expression in DMBA/TPA tumor induction. In contrast, myeloid Cox-2 gene deletion has no effect on DMBA/TPA tumorigenesis. The infrequent, small tumors that develop on mice with an epithelial cell-specific Cox-2 gene deletion have decreased proliferation and increased cell differentiation properties. Blood vessel density is reduced in tumors with an epithelial cell-specific Cox-2 gene deletion, compared to littermate control tumors, suggesting a reciprocal relationship in tumor progression between COX-2 expressing tumor epithelial cells and microenvironment endothelial cells. Lipidomics analysis of skin and tumors from DMBA/TPA-treated mice suggests that the prostaglandins PGE2 and PGF2α are likely candidates for the epithelial cell COX-2-dependent eicosanoids that mediate tumor progression. This study both illustrates the value of cell-type specific gene deletions in understanding the cellular roles of signal-generating pathways in complex microenvironments and emphasizes the benefit of a systems-based lipidomic analysis approach to identify candidate lipid mediators of biological responses. PMID:25063587

Novel Role for Interleukin-17 in Enhancing Type 1 Helper T Cell Immunity in the Female Genital Tract following Mucosal Herpes Simplex Virus 2 Vaccination.

PubMed

Bagri, Puja; Anipindi, Varun C; Nguyen, Philip V; Vitali, Danielle; Stämpfli, Martin R; Kaushic, Charu

2017-12-01

It is well established that interferon gamma (IFN-γ) production by CD4 + T cells is critical for antiviral immunity against herpes simplex virus 2 (HSV-2) genital infection. However, the role of interleukin-17A (IL-17A) production by CD4 + T cells in HSV-2 antiviral immunity is yet to be elucidated. Here we demonstrate that IL-17A plays an important role in enhancing antiviral T helper type 1 (T h 1) responses in the female genital tract (FGT) and is essential for effective protection conferred by HSV-2 vaccination. While IL-17A did not play a critical role during primary genital HSV-2 infection, seen by lack of differences in susceptibility between IL-17A-deficient ( IL-17A -/- ) and wild-type (WT) C57BL/6 mice, it was critical for mediating antiviral responses after challenge/reexposure. Compared to WT mice, IL-17A -/- mice (i) infected intravaginally and reexposed or (ii) vaccinated intranasally and challenged intravaginally demonstrated poor outcomes. Following intravaginal HSV-2 reexposure or challenge, vaccinated IL-17A -/- mice had significantly higher mortality, greater disease severity, higher viral shedding, and higher levels of proinflammatory cytokines and chemokines in vaginal secretions. Furthermore, IL-17A -/- mice had impaired T h 1 cell responses after challenge/reexposure, with significantly lower proportions of vaginal IFN-γ + CD4 + T cells. The impaired T h 1 cell responses in IL-17A -/- mice coincided with smaller populations of IFN-γ + CD4 + tissue resident memory T (T RM ) cells in the genital tract postimmunization. Taken together, these findings describe a novel role for IL-17A in regulating antiviral IFN-γ + T h 1 cell immunity in the vaginal tract. This strategy could be exploited to enhance antiviral immunity following HSV-2 vaccination. IMPORTANCE T helper type 1 (T h 1) immunity, specifically interferon gamma (IFN-γ) production by CD4 + T cells, is critical for protection against genital herpesvirus (HSV-2) infection, and enhancing this response can potentially help improve disease outcomes. Our study demonstrated that interleukin-17A (IL-17A) plays an essential role in enhancing antiviral T h 1 responses in the female genital tract (FGT). We found that in the absence of IL-17A, preexposed and vaccinated mice showed poor disease outcomes and were unable to overcome HSV-2 reexposure/challenge. IL-17A-deficient mice ( IL-17A -/- ) had smaller populations of IFN-γ + CD4 + tissue resident memory T (T RM ) cells in the genital tract postimmunization than did wild-type (WT) mice, which coincided with attenuated T h 1 responses postchallenge. This has important implications for developing effective vaccines against HSV-2, as we propose that strategies inducing IL-17A in the genital tract may promote more effective T h 1 cell immunity and better overall protection. Copyright © 2017 American Society for Microbiology.

Interleukin-33 in tumorigenesis, tumor immune evasion, and cancer immunotherapy.

PubMed

Lu, Binfeng; Yang, Min; Wang, Qingqing

2016-05-01

Interleukin-33 (IL-33) is a member of the IL-1 gene family and mainly expressed in the nucleus of tissue lining cells, stromal cells, and activated myeloid cells. IL-33 is considered a damage-associated molecular pattern (DAMP) molecule and plays an important role in many physiological and pathological settings such as tissue repair, allergy, autoimmune disease, infectious disease, and cancer. The biological functions of IL-33 include maintaining tissue homeostasis, enhancing type 1 and 2 cellular immune responses, and mediating fibrosis during chronic inflammation. IL-33 exerts diverse functions through signaling via its receptor ST2, which is expressed in many types of cells including regulatory T cells (Treg), group 2 innate lymphoid cells (ILC2s), myeloid cells, cytotoxic NK cells, Th2 cells, Th1 cells, and CD8(+) T cells. Tumor development results in downregulation of IL-33 in epithelial cells but upregulation of IL-33 in the tumor stroma and serum. The current data suggest that IL-33 expression in tumor cells increases immunogenicity and promotes type 1 antitumor immune responses through CD8(+) T cells and NK cells, whereas IL-33 in tumor stroma and serum facilitates immune suppression via Treg and myeloid-derived suppressor cell (MDSC). Understanding the role of IL-33 in cancer immunobiology sheds lights on targeting this cytokine for cancer immunotherapy.

Compound 49b Reduces Inflammatory Markers and Apoptosis after Ocular Blast Injury

DTIC Science & Technology

2014-09-01

drug, Compound 49b, have anti-apoptotic and anti-inflammatory properties in retinal endothelial cells and in a diabetic retinopathy model [7, 10...plays an important role in the development of early diabetic retinopathy and long-term histopathological alterations. Mol Vis, 2009; 15: 1418-28. 12...in other retinal damage models, specifically the streptozotocin- induced type 1 diabetic retinopathy model and retinal endothelial cells cultured in

DAB2IP-Coordinated miRNA Biogenesis

DTIC Science & Technology

2015-09-01

been implicated to play a tumor suppressor role in nasal-type natural killer/T-cell lymphoma 11, hepatocellular carcinoma and colorectal cancer...the EMT process in several cancer cell lines including PCa, hepatocellular carcinoma and renal cancer (Fig. 1). Most importantly, we elucidated a...blood-2011-07- 364224 (2011). 12 Zhou, P. et al. MicroRNA-363-mediated downregulation of S1PR1 suppresses the proliferation of hepatocellular

Expression of membrane-type 1 matrix metalloproteinase (MT1-MMP) on prostate cancer cell lines.

PubMed

Nagakawa, O; Murakami, K; Yamaura, T; Fujiuchi, Y; Murata, J; Fuse, H; Saiki, I

2000-07-31

Membrane-type metalloproteinase-1 (MT1-MMP) is a transmembrane metalloproteinase, which activates proMMP-2 and expressed on the cell surface in many invasive cancer cells. We investigated the expression of MT1-MMP in prostate cancer cell lines. MT1-MMP protein and mRNA were expressed in PC-3, DU-145 and TSU-pr1 cells (androgen-independent prostate cancer cell lines), but in LNCaP cells (androgen-dependent prostate cancer cell line). MT1-MMP protein was negative and mRNA was low to detect by RT-PCR. Cell lysate of PC-3 cleaved proMMP-2 to the active form. In addition, both hepatocyte growth factor (HGF) and gastrin-releasing peptide (GRP) increased Matrigel invasion and induced the expression of MT1-MMP protein in DU-145 prostate cancer cells. These results suggest that MT1-MMP is indeed the tumor-specific activator of proMMP-2 in androgen-independent prostate cancer cells and plays an important role in the invasive properties of prostate cancer cells.

The anti-tumor activity of E1A and its implications in cancer therapy.

PubMed

Chang, Yi-Wen; Hung, Mien-Chie; Su, Jen-Liang

2014-06-01

The adenovirus type 5 E1A protein (E1A) plays a critical role in anti-cancer gene therapy and has been tested in clinical trials. The expression of E1A significantly reduces tumorigenesis, promotes cell death, and inhibits cancer cell mobility. Chemosensitization is one of the anti-tumor effects of E1A, increasing in vitro and in vivo sensitization of anti-cancer drugs, including cisplatin, gemcitabine, etoposide, doxorubicin, paclitaxel, and tumor necrosis factor-related apoptosis-inducing ligand and histone deacetylase inhibitors in different types of cancer cells. E1A also demonstrates anti-metastasis activity through various molecular mechanisms such as the repression of protease expression, suppression of HER2/neu and downregulation of microRNA (miR-520h). Moreover, E1A has been reported to reprogram transcription in tumor cells and stabilize tumor suppressors such as PP2A/C, p21 and p53. Because E1A plays a potentially significant role in anti-tumor therapy, there exists an urgent need to study the anti-cancer activities of E1A. This paper presents a review of our current understanding of the tumor-suppressive functions and molecular regulation of E1A, as well as the potential clinical applications of E1A.

Down-regulation of Wild-type p53-induced Phosphatase 1 (Wip1) Plays a Critical Role in Regulating Several p53-dependent Functions in Premature Senescent Tumor Cells*

PubMed Central

Crescenzi, Elvira; Raia, Zelinda; Pacifico, Francesco; Mellone, Stefano; Moscato, Fortunato; Palumbo, Giuseppe; Leonardi, Antonio

2013-01-01

Premature or drug-induced senescence is a major cellular response to chemotherapy in solid tumors. The senescent phenotype develops slowly and is associated with chronic DNA damage response. We found that expression of wild-type p53-induced phosphatase 1 (Wip1) is markedly down-regulated during persistent DNA damage and after drug release during the acquisition of the senescent phenotype in carcinoma cells. We demonstrate that down-regulation of Wip1 is required for maintenance of permanent G2 arrest. In fact, we show that forced expression of Wip1 in premature senescent tumor cells induces inappropriate re-initiation of mitosis, uncontrolled polyploid progression, and cell death by mitotic failure. Most of the effects of Wip1 may be attributed to its ability to dephosphorylate p53 at Ser15 and to inhibit DNA damage response. However, we also uncover a regulatory pathway whereby suppression of p53 Ser15 phosphorylation is associated with enhanced phosphorylation at Ser46, increased p53 protein levels, and induction of Noxa expression. On the whole, our data indicate that down-regulation of Wip1 expression during premature senescence plays a pivotal role in regulating several p53-dependent aspects of the senescent phenotype. PMID:23612976

Feedback, Lineages and Self-Organizing Morphogenesis

PubMed Central

Calof, Anne L.; Lowengrub, John S.; Lander, Arthur D.

2016-01-01

Feedback regulation of cell lineage progression plays an important role in tissue size homeostasis, but whether such feedback also plays an important role in tissue morphogenesis has yet to be explored. Here we use mathematical modeling to show that a particular feedback architecture in which both positive and negative diffusible signals act on stem and/or progenitor cells leads to the appearance of bistable or bi-modal growth behaviors, ultrasensitivity to external growth cues, local growth-driven budding, self-sustaining elongation, and the triggering of self-organization in the form of lamellar fingers. Such behaviors arise not through regulation of cell cycle speeds, but through the control of stem or progenitor self-renewal. Even though the spatial patterns that arise in this setting are the result of interactions between diffusible factors with antagonistic effects, morphogenesis is not the consequence of Turing-type instabilities. PMID:26989903

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

Noh, Seol Ah, E-mail: s6022029@korea.ac.kr; Choi, Young-Im, E-mail: yichoi99@forest.go.kr; Cho, Jin-Seong, E-mail: jinsung3932@gmail.com

Brassinosteroids (BRs) play important roles in many aspects of plant growth and development, including regulation of vascular cambium activities and cell elongation. BR-induced BEE3 (brassinosteroid enhanced expression 3) is required for a proper BR response. Here, we identified a poplar (Populus alba × Populus glandulosa) BEE3-like gene, PagBEE3L, encoding a putative basic helix-loop-helix (bHLH)-type transcription factor. Expression of PagBEE3L was induced by brassinolide (BL). Transcripts of PagBEE3L were mainly detected in stems, with the internode having a low level of transcription and the node having a relatively higher level. The function of the PagBEE3L gene was investigated through phenotypic analyses with PagBEE3L-overexpressingmore » (ox) transgenic lines. This work particularly focused on a potential role of PagBEE3L in stem growth and development of polar. The PagBEE3L-ox poplar showed thicker and longer stems than wild-type plants. The xylem cells from the stems of PagBEE3L-ox plants revealed remarkably enhanced proliferation, resulting in an earlier thickening growth than wild-type plants. Therefore, this work suggests that xylem development of poplar is accelerated in PagBEE3L-ox plants and PagBEE3L plays a role in stem growth by increasing the proliferation of xylem cells to promote the initial thickening growth of poplar stems. - Highlights: • We identify the BEE3-like gene form hybrid poplar (Populus alba × Populus glandulosa). • We examine effects of overexpression of PagBEE3L on growth in poplar. • We found that 35S:BEE3L transgenic plants showed more rapid growth than wild-type plants. • BEE3L protein plays an important role in the development of plant stem.« less

N6-methyladenosine modification and the YTHDF2 reader protein play cell type specific roles in lytic viral gene expression during Kaposi's sarcoma-associated herpesvirus infection

PubMed Central

Dominissini, Dan; He, Chuan

2018-01-01

Methylation at the N6 position of adenosine (m6A) is a highly prevalent and reversible modification within eukaryotic mRNAs that has been linked to many stages of RNA processing and fate. Recent studies suggest that m6A deposition and proteins involved in the m6A pathway play a diverse set of roles in either restricting or modulating the lifecycles of select viruses. Here, we report that m6A levels are significantly increased in cells infected with the oncogenic human DNA virus Kaposi’s sarcoma-associated herpesvirus (KSHV). Transcriptome-wide m6A-sequencing of the KSHV-positive renal carcinoma cell line iSLK.219 during lytic reactivation revealed the presence of m6A across multiple kinetic classes of viral transcripts, and a concomitant decrease in m6A levels across much of the host transcriptome. However, we found that depletion of the m6A machinery had differential pro- and anti-viral impacts on viral gene expression depending on the cell-type analyzed. In iSLK.219 and iSLK.BAC16 cells the pathway functioned in a pro-viral manner, as depletion of the m6A writer METTL3 and the reader YTHDF2 significantly impaired virion production. In iSLK.219 cells the defect was linked to their roles in the post-transcriptional accumulation of the major viral lytic transactivator ORF50, which is m6A modified. In contrast, although the ORF50 mRNA was also m6A modified in KSHV infected B cells, ORF50 protein expression was instead increased upon depletion of METTL3, or, to a lesser extent, YTHDF2. These results highlight that the m6A pathway is centrally involved in regulating KSHV gene expression, and underscore how the outcome of this dynamically regulated modification can vary significantly between cell types. PMID:29659627

Bioelectric memory: modeling resting potential bistability in amphibian embryos and mammalian cells.

PubMed

Law, Robert; Levin, Michael

2015-10-15

Bioelectric gradients among all cells, not just within excitable nerve and muscle, play instructive roles in developmental and regenerative pattern formation. Plasma membrane resting potential gradients regulate cell behaviors by regulating downstream transcriptional and epigenetic events. Unlike neurons, which fire rapidly and typically return to the same polarized state, developmental bioelectric signaling involves many cell types stably maintaining various levels of resting potential during morphogenetic events. It is important to begin to quantitatively model the stability of bioelectric states in cells, to understand computation and pattern maintenance during regeneration and remodeling. To facilitate the analysis of endogenous bioelectric signaling and the exploitation of voltage-based cellular controls in synthetic bioengineering applications, we sought to understand the conditions under which somatic cells can stably maintain distinct resting potential values (a type of state memory). Using the Channelpedia ion channel database, we generated an array of amphibian oocyte and mammalian membrane models for voltage evolution. These models were analyzed and searched, by simulation, for a simple dynamical property, multistability, which forms a type of voltage memory. We find that typical mammalian models and amphibian oocyte models exhibit bistability when expressing different ion channel subsets, with either persistent sodium or inward-rectifying potassium, respectively, playing a facilitative role in bistable memory formation. We illustrate this difference using fast sodium channel dynamics for which a comprehensive theory exists, where the same model exhibits bistability under mammalian conditions but not amphibian conditions. In amphibians, potassium channels from the Kv1.x and Kv2.x families tend to disrupt this bistable memory formation. We also identify some common principles under which physiological memory emerges, which suggest specific strategies for implementing memories in bioengineering contexts. Our results reveal conditions under which cells can stably maintain one of several resting voltage potential values. These models suggest testable predictions for experiments in developmental bioelectricity, and illustrate how cells can be used as versatile physiological memory elements in synthetic biology, and unconventional computation contexts.

Analysis of Initial Cell Spreading Using Mechanistic Contact Formulations for a Deformable Cell Model

PubMed Central

Odenthal, Tim; Smeets, Bart; Van Liedekerke, Paul; Tijskens, Engelbert; Van Oosterwyck, Hans; Ramon, Herman

2013-01-01

Adhesion governs to a large extent the mechanical interaction between a cell and its microenvironment. As initial cell spreading is purely adhesion driven, understanding this phenomenon leads to profound insight in both cell adhesion and cell-substrate interaction. It has been found that across a wide variety of cell types, initial spreading behavior universally follows the same power laws. The simplest cell type providing this scaling of the radius of the spreading area with time are modified red blood cells (RBCs), whose elastic responses are well characterized. Using a mechanistic description of the contact interaction between a cell and its substrate in combination with a deformable RBC model, we are now able to investigate in detail the mechanisms behind this universal power law. The presented model suggests that the initial slope of the spreading curve with time results from a purely geometrical effect facilitated mainly by dissipation upon contact. Later on, the spreading rate decreases due to increasing tension and dissipation in the cell's cortex as the cell spreads more and more. To reproduce this observed initial spreading, no irreversible deformations are required. Since the model created in this effort is extensible to more complex cell types and can cope with arbitrarily shaped, smooth mechanical microenvironments of the cells, it can be useful for a wide range of investigations where forces at the cell boundary play a decisive role. PMID:24146605

Intermediate Filaments Play a Pivotal Role in Regulating Cell Architecture and Function.

PubMed

Lowery, Jason; Kuczmarski, Edward R; Herrmann, Harald; Goldman, Robert D

2015-07-10

Intermediate filaments (IFs) are composed of one or more members of a large family of cytoskeletal proteins, whose expression is cell- and tissue type-specific. Their importance in regulating the physiological properties of cells is becoming widely recognized in functions ranging from cell motility to signal transduction. IF proteins assemble into nanoscale biopolymers with unique strain-hardening properties that are related to their roles in regulating the mechanical integrity of cells. Furthermore, mutations in the genes encoding IF proteins cause a wide range of human diseases. Due to the number of different types of IF proteins, we have limited this short review to cover structure and function topics mainly related to the simpler homopolymeric IF networks composed of vimentin, and specifically for diseases, the related muscle-specific desmin IF networks. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Reduction of conventional dendritic cells during Plasmodium infection is dependent on activation induced cell death by type I and II interferons.

PubMed

Tamura, Takahiko; Kimura, Kazumi; Yui, Katsuyuki; Yoshida, Shigeto

2015-12-01

Dendritic cells (DCs) play critical roles in innate and adaptive immunity and in pathogenesis during the blood stage of malaria infection. The mechanisms underlying DC homeostasis during malaria infection are not well understood. In this study, the numbers of conventional DCs (cDCs) and plasmacytoid DCs (pDCs) in the spleens after lethal rodent malaria infection were examined, and were found to be significantly reduced. Concomitant with up-regulation of maturation-associated molecules, activation of caspase-3 was significantly increased, suggesting induction of cell death. Studies using neutralizing antibody and gene-deficient mice showed that type I and II interferons were critically involved in activation induced cell death of cDCs during malaria infection. These results demonstrate that DCs rapidly disappeared following IFN-mediated DC activation, and that homeostasis of DCs was significantly impaired during malaria infection. Copyright © 2015 Elsevier Inc. All rights reserved.

Perithecium morphogenesis in Sordaria macrospora.

PubMed

Lord, Kathryn M; Read, Nick D

2011-04-01

The perithecium of the self-fertile ascomycete Sordaria macrospora provides an excellent model in which to analyse fungal multicellular development. This study provides a detailed analysis of perithecium morphogenesis in the wild type and eight developmental mutants of S. macrospora, using a range of correlative microscopical techniques. Fundamentally, perithecia and other complex multicellular structures produced by fungi arise by hyphal aggregation and adhesion, and these processes are followed by specialization and septation of hyphal compartments within the aggregates. Perithecial morphogenesis can be divided into the ascogonial, protoperithecial, and perithecial stages of development. At least 13 specialized, morphologically distinct cell-types are involved in perithecium morphogenesis, and these fall into three basic classes: hyphae, conglutinate cells and spores. Conglutinate cells arise from hyphal adhesion and certain perithecial hyphae develop from conglutinate cells. Various hypha-conglutinate cell transitions play important roles during the development of the perithecial wall and neck. Copyright © 2010. Published by Elsevier Inc.

Emerging topics and new perspectives on HLA-G.

PubMed

Fainardi, Enrico; Castellazzi, Massimiliano; Stignani, Marina; Morandi, Fabio; Sana, Gwenaëlle; Gonzalez, Rafael; Pistoia, Vito; Baricordi, Olavio Roberto; Sokal, Etienne; Peña, Josè

2011-02-01

Following the Fifth International Conference on non-classical HLA-G antigens (HLA-G), held in Paris in July 2009, we selected some topics which focus on emerging aspects in the setting of HLA-G functions. In particular, HLA-G molecules could play a role in: (1) various inflammatory disorders, such as multiple sclerosis, intracerebral hemorrhage, gastrointestinal, skin and rheumatic diseases, and asthma, where they may act as immunoregulatory factors; (2) the mechanisms to escape immune surveillance utilized by several viruses, such as human cytomegalovirus, herpes simplex virus type 1, rabies virus, hepatitis C virus, influenza virus type A and human immunodeficiency virus 1 (HIV-1); and (3) cytokine/chemokine network and stem cell transplantation, since they seem to modulate cell migration by the downregulation of chemokine receptor expression and mesenchymal stem cell activity blocking of effector cell functions and the generation of regulatory T cells. However, the immunomodulatory circuits mediated by HLA-G proteins still remain to be clarified.

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

Liao, Xiao-hui; Zhang, Ling, E-mail: lindazhang8508@hotmail.com; Chen, Guo-tao

Tubular epithelial-to-mesenchymal transition (EMT) plays a crucial role in the progression of renal tubular interstitial fibrosis (TIF), which subsequently leads to chronic kidney disease (CKD) and eventually, end-stage renal disease (ESRD). We propose that augmenter of liver regeneration (ALR), a member of the newly discovered ALR/Erv1 protein family shown to ameliorate hepatic fibrosis, plays a similar protective role in renal tubular cells and has potential as a new treatment option for CKD. Here, we showed that recombinant human ALR (rhALR) inhibits EMT in renal tubular cells by antagonizing activation of the transforming growth factor-β1 (TGF-β1) signaling pathway. Further investigation revealedmore » that rhALR suppresses the expression of TGF-β receptor type II (TβR II) and significantly alleviates TGF-β1-induced phosphorylation of Smad2 and nuclear factor-κB (NF-κB). No apparent adverse effects were observed upon the addition of rhALR alone to cells. These findings collectively suggest that ALR plays a role in inhibiting progression of renal tubular EMT, supporting its potential utility as an effective antifibrotic strategy to reverse TIF in CKD. - Highlights: • ALR is involved in the pathological progression of renal EMT in NRK-52E cells. • ALR suppresses the expression of TβRII and the phosphorylation of Smad2 and NF-κB. • ALR plays a role in inhibiting progression of renal tubular EMT.« less

Molecular heterogeneity at the network level: high-dimensional testing, clustering and a TCGA case study | Office of Cancer Genomics

Cancer.gov

Motivation: Molecular pathways and networks play a key role in basic and disease biology. An emerging notion is that networks encoding patterns of molecular interplay may themselves differ between contexts, such as cell type, tissue or disease (sub)type. However, while statistical testing of differences in mean expression levels has been extensively studied, testing of network differences remains challenging.

Use of human antigen presenting cell gene array profiling to examine the effect of human T-cell leukemia virus type 1 Tax on primary human dendritic cells.

PubMed

Ahuja, Jaya; Kampani, Karan; Datta, Suman; Wigdahl, Brian; Flaig, Katherine E; Jain, Pooja

2006-02-01

Human T-cell leukemia virus type 1 (HTLV-1) is etiologically linked to adult T-cell leukemia and a progressive demyelinating disorder termed HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). One of the most striking features of the immune response in HAM/TSP centers on the expansion of HTLV-1-specific CD8(+) cytotoxic T lymphocyte (CTL) compartment in the peripheral blood and cerebrospinal fluid. More than 90% of the HTLV-1-specific CTLs are directed against the viral Tax (11-19) peptide implying that Tax is available for immune recognition by antigen presenting cells, such as dendritic cells (DCs). DCs obtained from HAM/TSP patients have been shown to be infected with HTLV-1 and exhibit rapid maturation. Therefore, we hypothesized that presentation of Tax peptides by activated DCs to naIve CD8(+) T cells may play an important role in the induction of a Tax-specific CTL response and neurologic dysfunction. In this study, a pathway-specific antigen presenting cell gene array was used to study transcriptional changes induced by exposure of monocyte-derived DCs to extracellular HTLV-1 Tax protein. Approximately 100 genes were differentially expressed including genes encoding toll-like receptors, cell surface receptors, proteins involved in antigen uptake and presentation and adhesion molecules. The differential regulation of chemokines and cytokines characteristic of functional DC activation was also observed by the gene array analyses. Furthermore, the expression pattern of signal transduction genes was also significantly altered. These results have suggested that Tax-mediated DC gene regulation might play a critical role in cellular activation and the mechanisms resulting in HTLV-1-induced disease.

Myonuclear Domain Flexibility Challenges Rigid Assumptions on Satellite Cell Contribution to Skeletal Muscle Fiber Hypertrophy.

PubMed

Murach, Kevin A; Englund, Davis A; Dupont-Versteegden, Esther E; McCarthy, John J; Peterson, Charlotte A

2018-01-01

Satellite cell-mediated myonuclear accretion is thought to be required for skeletal muscle fiber hypertrophy, and even drive hypertrophy by preceding growth. Recent studies in humans and rodents provide evidence that challenge this axiom. Specifically, Type 2 muscle fibers reliably demonstrate a substantial capacity to hypertrophy in the absence of myonuclear accretion, challenging the notion of a tightly regulated myonuclear domain (i.e., area that each myonucleus transcriptionally governs). In fact, a "myonuclear domain ceiling", or upper limit of transcriptional output per nucleus to support hypertrophy, has yet to be identified. Satellite cells respond to muscle damage, and also play an important role in extracellular matrix remodeling during loading-induced hypertrophy. We postulate that robust satellite cell activation and proliferation in response to mechanical loading is largely for these purposes. Future work will aim to elucidate the mechanisms by which Type 2 fibers can hypertrophy without additional myonuclei, the extent to which Type 1 fibers can grow without myonuclear accretion, and whether a true myonuclear domain ceiling exists.

The innate and adaptive infiltrating immune systems as targets for breast cancer immunotherapy

PubMed Central

Law, Andrew M K; Lim, Elgene; Ormandy, Christopher J

2017-01-01

A cancer cell-centric view has long dominated the field of cancer biology. Research efforts have focussed on aberrant cancer cell signalling pathways and on changes to cancer cell DNA. Mounting evidence demonstrates that many cancer-associated cell types within the tumour stroma co-evolve and support tumour growth and development, greatly modifying cancer cell behaviour, facilitating invasion and metastasis and controlling dormancy and sensitivity to drug therapy. Thus, these stromal cells represent potential targets for cancer therapy. Among these cell types, immune cells have emerged as a promising target for therapy. The adaptive and the innate immune system play an important role in normal mammary development and breast cancer. The number of infiltrating adaptive immune system cells with tumour-rejecting capacity, primarily, T lymphocytes, is lower in breast cancer compared with other cancer types, but infiltration occurs in a large proportion of cases. There is strong evidence demonstrating the importance of the immunosuppressive role of the innate immune system during breast cancer progression. A consideration of components of both the innate and the adaptive immune system is essential for the design and development of immunotherapies in breast cancer. In this review, we focus on the importance of immunosuppressive myeloid-derived suppressor cells (MDSCs) as potential targets for breast cancer therapy. PMID:28193698

The innate and adaptive infiltrating immune systems as targets for breast cancer immunotherapy.

PubMed

Law, Andrew M K; Lim, Elgene; Ormandy, Christopher J; Gallego-Ortega, David

2017-04-01

A cancer cell-centric view has long dominated the field of cancer biology. Research efforts have focussed on aberrant cancer cell signalling pathways and on changes to cancer cell DNA. Mounting evidence demonstrates that many cancer-associated cell types within the tumour stroma co-evolve and support tumour growth and development, greatly modifying cancer cell behaviour, facilitating invasion and metastasis and controlling dormancy and sensitivity to drug therapy. Thus, these stromal cells represent potential targets for cancer therapy. Among these cell types, immune cells have emerged as a promising target for therapy. The adaptive and the innate immune system play an important role in normal mammary development and breast cancer. The number of infiltrating adaptive immune system cells with tumour-rejecting capacity, primarily, T lymphocytes, is lower in breast cancer compared with other cancer types, but infiltration occurs in a large proportion of cases. There is strong evidence demonstrating the importance of the immunosuppressive role of the innate immune system during breast cancer progression. A consideration of components of both the innate and the adaptive immune system is essential for the design and development of immunotherapies in breast cancer. In this review, we focus on the importance of immunosuppressive myeloid-derived suppressor cells (MDSCs) as potential targets for breast cancer therapy. © 2017 The authors.

Infection with human herpesvirus type 8 and human T-cell leukaemia virus type 1 among individuals participating in a case–control study in Havana City, Cuba

PubMed Central

Fernandez, L; Serraino, D; Rezza, G; Lence, J; Ortiz, R M; Cruz, T; Vaccarella, S; Sarmati, L; Andreoni, M; Franceschi, S

2002-01-01

Infection with human herpesvirus type 8 and with human T-cell leukaemia virus type-1 shows strong geographic variations. We conducted this study to assess prevalence and risk factors for human herpesvirus type 8 infection in Havana City, Cuba. Information and residual serum samples already collected for a hospital based case–control study were used. A total of 379 individuals (267 males and 112 females; median age=63 years) were evaluated. Antibodies to the lytic antigen of human herpesvirus type 8 were detected by using an immunofluorescence assay, while human T-cell leukaemia virus type-1 serology was performed by means of an ELISA test (alpha Biotech). Overall, 64 subjects (16.9%, 95% confidence interval: 13.1–20.0) were positive for human herpesvirus type 8 antibodies. Human herpesvirus type 8 seroprevalence significantly increased with age (odds ratio=1.9 for ⩾65 vs <55 years), and was twice as frequent in blacks than in whites. No association emerged with gender, socio-economic indicators, family size, history of sexually transmitted disease, sexual behaviour. Overall, 16 persons had anti-human T-cell leukaemia virus type-1 antibodies (4.2%, 95% confidence interval: 2.2–6.4). No relationship emerged between human T-cell leukaemia virus type-1 and human herpesvirus type 8 serostatus. The study findings indicate that human herpesvirus type 8 infection is relatively common in Havana City, Cuba, suggesting that Cuba may represent an intermediate endemical area. Sexual transmission does not seem to play a major role in the spread human herpesvirus type 8 infection. British Journal of Cancer (2002) 87, 1253–1256. doi:10.1038/sj.bjc.6600613 www.bjcancer.com © 2002 Cancer Research UK PMID:12439714

Redox Regulation of Epithelial Sodium Channels Examined in Alveolar Type 1 and 2 Cells Patch-clamped in Lung Slice Tissue*

PubMed Central

Helms, My N.; Jain, Lucky; Self, Julie L.; Eaton, Douglas C.

2008-01-01

The alveolar surface of the lung is lined by alveolar type 1 (AT1) and type 2 (AT2) cells. Using single channel patch clamp analysis in lung slice preparations, we are able to uniquely study AT1 and AT2 cells separately from intact lung. We report for the first time the Na+ transport properties of type 2 cells accessed in live lung tissue (as we have done in type 1 cells). Type 2 cells in lung tissue slices express both highly selective cation and nonselective cation channels with average conductances of 8.8 ± 3.2 and 22.5 ± 6.3 picosiemens, respectively. Anion channels with 10-picosiemen conductance are also present in the apical membrane of type 2 cells. Our lung slice studies importantly verify the use of cultured cell model systems commonly used in lung epithelial sodium channel (ENaC) studies. Furthermore, we identify novel functional differences between the cells that make up the alveolar epithelium. One important difference is that exposure to the nitric oxide (NO) donor, PAPA-NONOate (1.5 μm), significantly decreases average ENaC NPo in type 2 cells (from 1.38 ± 0.26 to 0.82 ± 0.16; p < 0.05 and n = 18) but failed to alter ENaC activity in alveolar type 1 cells. Elevating endogenous superoxide (\\documentclass[10pt]{article} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{pmc} \\usepackage[Euler]{upgreek} \\pagestyle{empty} \\oddsidemargin -1.0in \\begin{document} \\begin{equation*}{\\mathrm{O}}_{2}^{\\overline{.}}\\end{equation*}\\end{document}) levels with Ethiolat, a superoxide dismutase inhibitor, prevented NO inhibition of ENaC activity in type 2 cells, supporting the novel hypothesis that \\documentclass[10pt]{article} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{pmc} \\usepackage[Euler]{upgreek} \\pagestyle{empty} \\oddsidemargin -1.0in \\begin{document} \\begin{equation*}{\\mathrm{O}}_{2}^{\\overline{.}}\\end{equation*}\\end{document} and NO signaling plays an important role in maintaining lung fluid balance. PMID:18541535

Expression of Tlx in both stem cells and transit amplifying progenitors regulates stem cell activation and differentiation in the neonatal lateral subependymal zone.

PubMed

Obernier, Kirsten; Simeonova, Ina; Fila, Tatiana; Mandl, Claudia; Hölzl-Wenig, Gabriele; Monaghan-Nichols, Paula; Ciccolini, Francesca

2011-09-01

Niche homeostasis in the postnatal subependymal zone of the lateral ventricle (lSEZ) requires coordinated proliferation and differentiation of neural progenitor cells. The mechanisms regulating this balance are scarcely known. Recent observations indicate that the orphan nuclear receptor Tlx is an intrinsic factor essential in maintaining this balance. However, the effect of Tlx on gene expression depends on age and cell-type cues. Therefore, it is essential to establish its expression pattern at different developmental ages. Here, we show for the first time that in the neonatal lSEZ activated neural stem cells (NSCs) and especially transit-amplifying progenitors (TAPs) express Tlx and that its expression may be regulated at the posttranscriptional level. We also provide evidence that in both cell types Tlx affects gene expression in a positive and negative manner. In activated NSCs, but not in TAPs, absence of Tlx leads to overexpression of negative cell cycle regulators and impairment of proliferation. Moreover, in both cell types, the homeobox transcription factor Dlx2 is downregulated in the absence of Tlx. This is paralleled by increased expression of Olig2 in activated NSCs and glial fibrillary acidic protein in TAPs, indicating that in both populations Tlx decreases gliogenesis. Consistent with this, we found a higher proportion of cells expressing glial makers in the neonatal lSEZ of mutant mice than in the wild type counterpart. Thus, Tlx playing a dual role affects the expression of distinct genes in these two lSEZ cell types. Copyright © 2011 AlphaMed Press.

The impact of homologous recombination repair deficiency on depleted uranium clastogenicity in Chinese hamster ovary cells: XRCC3 protects cells from chromosome aberrations, but increases chromosome fragmentation.

PubMed

Holmes, Amie L; Joyce, Kellie; Xie, Hong; Falank, Carolyne; Hinz, John M; Wise, John Pierce

2014-04-01

Depleted uranium (DU) is extensively used in both industry and military applications. The potential for civilian and military personnel exposure to DU is rising, but there are limited data on the potential health hazards of DU exposure. Previous laboratory research indicates DU is a potential carcinogen, but epidemiological studies remain inconclusive. DU is genotoxic, inducing DNA double strand breaks, chromosome damage and mutations, but the mechanisms of genotoxicity or repair pathways involved in protecting cells against DU-induced damage remain unknown. The purpose of this study was to investigate the effects of homologous recombination repair deficiency on DU-induced genotoxicity using RAD51D and XRCC3-deficient Chinese hamster ovary (CHO) cell lines. Cells deficient in XRCC3 (irs1SF) exhibited similar cytotoxicity after DU exposure compared to wild-type (AA8) and XRCC3-complemented (1SFwt8) cells, but DU induced more break-type and fusion-type lesions in XRCC3-deficient cells compared to wild-type and XRCC3-complemented cells. Surprisingly, loss of RAD51D did not affect DU-induced cytotoxicity or genotoxicity. DU induced selective X-chromosome fragmentation irrespective of RAD51D status, but loss of XRCC3 nearly eliminated fragmentation observed after DU exposure in wild-type and XRCC3-complemented cells. Thus, XRCC3, but not RAD51D, protects cells from DU-induced breaks and fusions and also plays a role in DU-induced chromosome fragmentation. Copyright © 2014 Elsevier B.V. All rights reserved.

Interleukin-18 and CD30 serum levels in patients with moderate-severe depression.

PubMed Central

Merendino, Rosaria Alba; Di Rosa, Antonio Enrico; Di Pasquale, Giuseppe; Minciullo, Paola Lucia; Mangraviti, Carmela; Costantino, Antonella; Ruello, Antonella; Gangemi, Sebastiano

2002-01-01

Interleukin-18 (IL-18), a pro-inflammatory cytokine that plays an important role in the T-cell-helper type 1 response, is a new member of the family of cytokines produced in the brain. CD30 is a marker of T-cell-helper type 2 lymphocytes. We evaluated IL-18 and CD30 serum levels in 10 patients affected by moderate-severe depression (MSD). We demonstrated for the first time that serum IL-18 levels of MSD patients were significantly higher than those of healthy donors. On the contrary, no significant difference was found between serum CD30 levels of MSD patients compared with those of healthy donors. These data strengthen the hypothesis that MSD disease is associated with an inflammatory response, mainly T-cell-helper type 1, and suggest an important role for IL-18 in the pathophysiology of MSD. PMID:12396479

[The physiology of glucagon-like peptide-1 and its role in the pathophysiology of type 2 diabetes mellitus].

PubMed

Escalada, Francisco Javier

2014-01-01

The hormone glucagon-like peptide-1 (GLP-1) is synthesized and secreted by L cells in the small intestine in response to food ingestion. After reaching the general circulation it has a half-life of 2-3 minutes due to degradation by the enzyme dipeptidyl peptidase-4. Its physiological role is directed to control plasma glucose concentration, though GLP-1 also plays other different metabolic functions following nutrient absorption. Biological activities of GLP-1 include stimulation of insulin biosynthesis and glucose-dependent insulin secretion by pancreatic beta cell, inhibition of glucagon secretion, delay of gastric emptying and inhibition of food intake. GLP-1 is able to reduce plasma glucose levels in patients with type 2 diabetes and also can restore beta cell sensitivity to exogenous secretagogues, suggesting that the increasing GLP-1 concentration may be an useful therapeutic strategy for the treatment of patients with type 2 diabetes.

Innovative application of classic and newer techniques for the characterization of haemocytes in the New Zealand black-footed abalone (Haliotis iris).

PubMed

Grandiosa, Roffi; Mérien, Fabrice; Pillay, Krish; Alfaro, Andrea

2016-01-01

Haemocytes play an important role in innate immune responses within invertebrate organisms. However, identification and quantification of different types of haemocytes can be extremely challenging, and has led to numerous inconsistencies and misinterpretations within the literature. As a step to rectify this issue, we present a comprehensive and detailed approach to characterize haemocytes using a combination of classical (cytochemical and phagocytosis assays with optical microscopy) and novel (flow cytometry with Sysmex XN-1000 and Muse(®) Cell analyser) techniques. The Sysmex XN-1000 is an innovative fluorescent flow cytometric analyser that can effectively detect, identify and count haemocytes, while the Muse(®) Cell analyser provides accurate and rapid haemocyte cell counts and viability. To illustrate this approach, we present the first report on morphological and functional features of New Zealand black-footed abalone (Haliotis iris) haemocyte cells. Two types of haemocytes were identified in this study, including type I (monocyte-like) and type II (lymphocyte-like) cells. Granular cells, which have been reported in other molluscan species, were not detected in H. iris. Cell types were categorized based on shape, size, internal structures and function. The lymphocyte-like haemocytes were the most abundant hemocytes in the haemolymph samples, and they had large nuclei and basic cytoplasms. Monocyte-like cells generally were larger cells compared to lymphocyte-like cells, and had low nucleus-cytoplasm ratios. Monocyte-like cells showed higher phagocytic activity when encountering Zymosan A particles compared to lymphocyte-like cells. The present study provides a comprehensive and accurate new approach to identify and quantify haemocyte cells for future comparative studies on the immune system of abalone and other molluscan species. Copyright © 2015 Elsevier Ltd. All rights reserved.

Engineering zonal cartilage through bioprinting collagen type II hydrogel constructs with biomimetic chondrocyte density gradient.

PubMed

Ren, Xiang; Wang, Fuyou; Chen, Cheng; Gong, Xiaoyuan; Yin, Li; Yang, Liu

2016-07-20

Cartilage tissue engineering is a promising approach for repairing and regenerating cartilage tissue. To date, attempts have been made to construct zonal cartilage that mimics the cartilaginous matrix in different zones. However, little attention has been paid to the chondrocyte density gradient within the articular cartilage. We hypothesized that the chondrocyte density gradient plays an important role in forming the zonal distribution of extracellular matrix (ECM). In this study, collagen type II hydrogel/chondrocyte constructs were fabricated using a bioprinter. Three groups were created according to the total cell seeding density in collagen type II pre-gel: Group A, 2 × 10(7) cells/mL; Group B, 1 × 10(7) cells/mL; and Group C, 0.5 × 10(7) cells/mL. Each group included two types of construct: one with a biomimetic chondrocyte density gradient and the other with a single cell density. The constructs were cultured in vitro and harvested at 0, 1, 2, and 3 weeks for cell viability testing, reverse-transcription quantitative PCR (RT-qPCR), biochemical assays, and histological analysis. We found that total ECM production was positively correlated with the total cell density in the early culture stage, that the cell density gradient distribution resulted in a gradient distribution of ECM, and that the chondrocytes' biosynthetic ability was affected by both the total cell density and the cell distribution pattern. Our results suggested that zonal engineered cartilage could be fabricated by bioprinting collagen type II hydrogel constructs with a biomimetic cell density gradient. Both the total cell density and the cell distribution pattern should be optimized to achieve synergistic biological effects.

Ceramide-1-phosphate regulates migration of multipotent stromal cells (MSCs) and endothelial progenitor cells (EPCs) – implications for tissue regeneration

PubMed Central

Kim, ChiHwa; Schneider, Gabriela; Abdel-Latif, Ahmed; Mierzejewska, Kasia; Sunkara, Manjula; Borkowska, Sylwia; Ratajczak, Janina; Morris, Andrew J.; Kucia, Magda; Ratajczak, Mariusz Z.

2012-01-01

Ceramide-1-phosphate (C1P) is a bioactive lipid that, in contrast to ceramide, is an anti-apoptotic molecule released from cells that are damaged and “leaky”. As reported recently, C1P promotes migration of hematopoietic cells. In the current paper, we tested the hypothesis that C1P released upon tissue damage may play an underappreciated role in chemoattraction of various types of stem cells and endothelial cells involved in tissue/organ regeneration. We show for a first time that C1P is upregulated in damaged tissues and chemoattracts BM-derived multipotent stroma cells (MSCs), endothelial progenitor cells (EPCs), and very small embryonic-like stem cells (VSELs). Furthermore, compared to other bioactive lipids, C1P more potently chemoattracted human umbilical vein endothelial cells (HUVECs) and stimulated tube formation by these cells. C1P also promoted in vivo vascularization of Matrigel implants and stimulated secretion of stromal derived factor-1 (SDF-1) from BM-derived fibroblasts. Thus, our data demonstrate, for the first time, that C1P is a potent bioactive lipid released from damaged cells that potentially plays an important and novel role in recruitment of stem/progenitor cells to damaged organs and may promote their vascularization. PMID:23193025

Functional analysis of a viroid RNA motif mediating cell-to-cell movement in Nicotiana benthamiana.

PubMed

Jiang, Dongmei; Wang, Meng; Li, Shifang

2017-01-01

Cell-to-cell trafficking through different cellular layers is a key process for various RNAs including those of plant viruses and viroids, but the regulatory mechanisms involved are still not fully elucidated and good model systems are important. Here, we analyse the function of a simple RNA motif (termed 'loop19') in potato spindle tuber viroid (PSTVd) which is required for trafficking in Nicotiana benthamiana leaves. Northern blotting, reverse transcriptase PCR (RT-PCR) and in situ hybridization analyses demonstrated that unlike wild-type PSTVd, which was present in the nuclei in all cell types, the trafficking-defective loop19 mutants were visible only in the nuclei of upper epidermal and palisade mesophyll cells, which shows that PSTVd loop19 plays a role in mediating RNA trafficking from palisade to spongy mesophyll cells in N.benthamiana leaves. Our findings and approaches have broad implications for studying the RNA motifs mediating trafficking of RNAs across specific cellular boundaries in other biological systems.

Metabolic responses induced by DNA damage and poly (ADP-ribose) polymerase (PARP) inhibition in MCF-7 cells

PubMed Central

Bhute, Vijesh J.; Palecek, Sean P.

2015-01-01

Genomic instability is one of the hallmarks of cancer. Several chemotherapeutic drugs and radiotherapy induce DNA damage to prevent cancer cell replication. Cells in turn activate different DNA damage response (DDR) pathways to either repair the damage or induce cell death. These DDR pathways also elicit metabolic alterations which can play a significant role in the proper functioning of the cells. The understanding of these metabolic effects resulting from different types of DNA damage and repair mechanisms is currently lacking. In this study, we used NMR metabolomics to identify metabolic pathways which are altered in response to different DNA damaging agents. By comparing the metabolic responses in MCF-7 cells, we identified the activation of poly (ADP-ribose) polymerase (PARP) in methyl methanesulfonate (MMS)-induced DNA damage. PARP activation led to a significant depletion of NAD+. PARP inhibition using veliparib (ABT-888) was able to successfully restore the NAD+ levels in MMS-treated cells. In addition, double strand break induction by MMS and veliparib exhibited similar metabolic responses as zeocin, suggesting an application of metabolomics to classify the types of DNA damage responses. This prediction was validated by studying the metabolic responses elicited by radiation. Our findings indicate that cancer cell metabolic responses depend on the type of DNA damage responses and can also be used to classify the type of DNA damage. PMID:26478723

The bHLH Repressor Deadpan Regulates the Self-renewal and Specification of Drosophila Larval Neural Stem Cells Independently of Notch

PubMed Central

Younger, Susan; Huang, Yaling; Lee, Tzumin

2012-01-01

Neural stem cells (NSCs) are able to self-renew while giving rise to neurons and glia that comprise a functional nervous system. However, how NSC self-renewal is maintained is not well understood. Using the Drosophila larval NSCs called neuroblasts (NBs) as a model, we demonstrate that the Hairy and Enhancer-of-Split (Hes) family protein Deadpan (Dpn) plays important roles in NB self-renewal and specification. The loss of Dpn leads to the premature loss of NBs and truncated NB lineages, a process likely mediated by the homeobox protein Prospero (Pros). Conversely, ectopic/over-expression of Dpn promotes ectopic self-renewing divisions and maintains NB self-renewal into adulthood. In type II NBs, which generate transit amplifying intermediate neural progenitors (INPs) like mammalian NSCs, the loss of Dpn results in ectopic expression of type I NB markers Asense (Ase) and Pros before these type II NBs are lost at early larval stages. Our results also show that knockdown of Notch leads to ectopic Ase expression in type II NBs and the premature loss of type II NBs. Significantly, dpn expression is unchanged in these transformed NBs. Furthermore, the loss of Dpn does not inhibit the over-proliferation of type II NBs and immature INPs caused by over-expression of activated Notch. Our data suggest that Dpn plays important roles in maintaining NB self-renewal and specification of type II NBs in larval brains and that Dpn and Notch function independently in regulating type II NB proliferation and specification. PMID:23056424

Bmi-1 plays a critical role in the protection from acute tubular necrosis by mobilizing renal stem/progenitor cells.

PubMed

Lv, Xianhui; Yu, Zhenzhen; Xie, Chunfeng; Dai, Xiuliang; Li, Qing; Miao, Dengshun; Jin, Jianliang

2017-01-22

The regeneration of injured tubular cell occurs primarily from intrinsic renal stem/progenitor cells (RSCs) labeled with CD24 and CD133 after acute tubular necrosis (ATN). Bmi-1 plays a crucial role in regulating self-renewal, differentiation and aging of multiple adult stem cells and progenitor cells. Bmi-1 was rapidly elevated in the induction of adult kidney regeneration by renal injury. To determine whether Bmi-1 maintained mobilization of RSCs in the protection from ATN, glycerol-rhabdomyolysis-induced ATN were performed in wild type (WT) and Bmi-1-deficient (Bmi-1 -/- ) mice. Their ATN phenotypes were analyzed; CD24 and CD133 double positive (CD24 + CD133 + ) cells were measured; and the levels of serum urea nitrogen (SUN) and serum creatinine (SCr) were detected. We found that CD24 + CD133 + RSCs were mobilized in WT ATN mice with the increased expression of Bmi-1; Bmi-1 deficiency led to increased tubular cast formation and necrosis, elevated levels of SUN and SCr, decreased tubular proliferation, and immobilized ratio of RSCs in ATN. These findings indicated that Bmi-1 played a critical role in the protection from ATN by maintaining mobilization of RSCs and would be a novel therapeutic target for preventing the progression of ATN. Copyright © 2016 Elsevier Inc. All rights reserved.

Bmi-1 plays a critical role in the protection from acute tubular necrosis by mobilizing renal stem/progenitor cells

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

Lv, Xianhui; Yu, Zhenzhen; Xie, Chunfeng

The regeneration of injured tubular cell occurs primarily from intrinsic renal stem/progenitor cells (RSCs) labeled with CD24 and CD133 after acute tubular necrosis (ATN). Bmi-1 plays a crucial role in regulating self-renewal, differentiation and aging of multiple adult stem cells and progenitor cells. Bmi-1 was rapidly elevated in the induction of adult kidney regeneration by renal injury. To determine whether Bmi-1 maintained mobilization of RSCs in the protection from ATN, glycerol-rhabdomyolysis-induced ATN were performed in wild type (WT) and Bmi-1-deficient (Bmi-1{sup −/−}) mice. Their ATN phenotypes were analyzed; CD24 and CD133 double positive (CD24{sup +}CD133{sup +}) cells were measured; andmore » the levels of serum urea nitrogen (SUN) and serum creatinine (SCr) were detected. We found that CD24{sup +}CD133{sup +} RSCs were mobilized in WT ATN mice with the increased expression of Bmi-1; Bmi-1 deficiency led to increased tubular cast formation and necrosis, elevated levels of SUN and SCr, decreased tubular proliferation, and immobilized ratio of RSCs in ATN. These findings indicated that Bmi-1 played a critical role in the protection from ATN by maintaining mobilization of RSCs and would be a novel therapeutic target for preventing the progression of ATN.« less

Mps1 is SUMO-modified during the cell cycle

PubMed Central

Chen, Changyan; Lu, Lou; Dai, Wei

2016-01-01

Mps1 is a dual specificity protein kinase that regulates the spindle assembly checkpoint and mediates proper microtubule attachment to chromosomes during mitosis. However, the molecular mechanism that controls Mps1 protein level and its activity during the cell cycle remains unclear. Given that sumoylation plays an important role in mitotic progression, we investigated whether Mps1 was SUMO-modified and whether sumoylation affects its activity in mitosis. Our results showed that Mps1 was sumoylated in both asynchronized and mitotic cell populations. Mps1 was modified by both SUMO-1 and SUMO-2. Our further studies revealed that lysine residues including K71, K287, K367 and K471 were essential for Mps1 sumoylation. Sumoylation appeared to play a role in mediating kinetochore localization of Mps1, thus affecting normal mitotic progression. Furthermore, SUMO-resistant mutants of Mps1 interacted with BubR1 more efficiently than it did with the wild-type control. Combined, our results indicate that Mps1 is SUMO-modified that plays an essential role in regulating Mps1 functions during mitosis. PMID:26675261

Mps1 is SUMO-modified during the cell cycle.

PubMed

Restuccia, Agnese; Yang, Feikun; Chen, Changyan; Lu, Lou; Dai, Wei

2016-01-19

Mps1 is a dual specificity protein kinase that regulates the spindle assembly checkpoint and mediates proper microtubule attachment to chromosomes during mitosis. However, the molecular mechanism that controls Mps1 protein level and its activity during the cell cycle remains unclear. Given that sumoylation plays an important role in mitotic progression, we investigated whether Mps1 was SUMO-modified and whether sumoylation affects its activity in mitosis. Our results showed that Mps1 was sumoylated in both asynchronized and mitotic cell populations. Mps1 was modified by both SUMO-1 and SUMO-2. Our further studies revealed that lysine residues including K71, K287, K367 and K471 were essential for Mps1 sumoylation. Sumoylation appeared to play a role in mediating kinetochore localization of Mps1, thus affecting normal mitotic progression. Furthermore, SUMO-resistant mutants of Mps1 interacted with BubR1 more efficiently than it did with the wild-type control. Combined, our results indicate that Mps1 is SUMO-modified that plays an essential role in regulating Mps1 functions during mitosis.

Role of innate and adaptive immunity in obesity-associated metabolic disease

PubMed Central

McLaughlin, Tracey; Ackerman, Shelley E.; Shen, Lei

2017-01-01

Chronic inflammation in adipose tissue, possibly related to adipose cell hypertrophy, hypoxia, and/or intestinal leakage of bacteria and their metabolic products, likely plays a critical role in the development of obesity-associated insulin resistance (IR). Cells of both the innate and adaptive immune system residing in adipose tissues, as well as in the intestine, participate in this process. Thus, M1 macrophages, IFN-γ–secreting Th1 cells, CD8+ T cells, and B cells promote IR, in part through secretion of proinflammatory cytokines. Conversely, eosinophils, Th2 T cells, type 2 innate lymphoid cells, and possibly Foxp3+ Tregs protect against IR through local control of inflammation. PMID:28045397

The effect of types I and III interferons on adrenocortical cells and its possible implications for autoimmune Addison's disease.

PubMed

Hellesen, A; Edvardsen, K; Breivik, L; Husebye, E S; Bratland, E

2014-06-01

Autoimmune Addison's disease (AAD) is caused by selective destruction of the hormone-producing cells of the adrenal cortex. As yet, little is known about the potential role played by environmental factors in this process. Type I and/or type III interferons (IFNs) are signature responses to virus infections, and have also been implicated in the pathogenesis of autoimmune endocrine disorders such as type 1 diabetes and autoimmune thyroiditis. Transient development of AAD and exacerbation of established or subclinical disease, as well as the induction of autoantibodies associated with AAD, have been reported following therapeutic administration of type I IFNs. We therefore hypothesize that exposure to such IFNs could render the adrenal cortex susceptible to autoimmune attack in genetically predisposed individuals. In this study, we investigated possible immunopathological effects of type I and type III IFNs on adrenocortical cells in relation to AAD. Both types I and III IFNs exerted significant cytotoxicity on NCI-H295R adrenocortical carcinoma cells and potentiated IFN-γ- and polyinosine-polycytidylic acid [poly (I : C)]-induced chemokine secretion. Furthermore, we observed increased expression of human leucocyte antigen (HLA) class I molecules and up-regulation of 21-hydroxylase, the primary antigenic target in AAD. We propose that these combined effects could serve to initiate or aggravate an ongoing autoimmune response against the adrenal cortex in AAD. © 2014 British Society for Immunology.

The effect of types I and III interferons on adrenocortical cells and its possible implications for autoimmune Addison's disease

PubMed Central

Hellesen, A; Edvardsen, K; Breivik, L; Husebye, E S; Bratland, E

2014-01-01

Autoimmune Addison's disease (AAD) is caused by selective destruction of the hormone-producing cells of the adrenal cortex. As yet, little is known about the potential role played by environmental factors in this process. Type I and/or type III interferons (IFNs) are signature responses to virus infections, and have also been implicated in the pathogenesis of autoimmune endocrine disorders such as type 1 diabetes and autoimmune thyroiditis. Transient development of AAD and exacerbation of established or subclinical disease, as well as the induction of autoantibodies associated with AAD, have been reported following therapeutic administration of type I IFNs. We therefore hypothesize that exposure to such IFNs could render the adrenal cortex susceptible to autoimmune attack in genetically predisposed individuals. In this study, we investigated possible immunopathological effects of type I and type III IFNs on adrenocortical cells in relation to AAD. Both types I and III IFNs exerted significant cytotoxicity on NCI-H295R adrenocortical carcinoma cells and potentiated IFN-γ-and polyinosine-polycytidylic acid [poly (I : C)]-induced chemokine secretion. Furthermore, we observed increased expression of human leucocyte antigen (HLA) class I molecules and up-regulation of 21-hydroxylase, the primary antigenic target in AAD. We propose that these combined effects could serve to initiate or aggravate an ongoing autoimmune response against the adrenal cortex in AAD. PMID:24666275

Antisense inhibition of hyaluronan synthase-2 in human osteosarcoma cells inhibits hyaluronan retention and tumorigenicity

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

Nishida, Yoshihiro; Knudson, Warren; Knudson, Cheryl B.

2005-07-01

Osteosarcoma is a common malignant bone tumor associated with childhood and adolescence. The results of numerous studies have suggested that hyaluronan plays an important role in regulating the aggressive behavior of various types of cancer cells. However, no studies have addressed hyaluronan with respect to osteosarcomas. In this investigation, the mRNA expression copy number of three mammalian hyaluronan synthases (HAS) was determined using competitive RT-PCR in the osteoblastic osteosarcoma cell line, MG-63. MG-63 are highly malignant osteosarcoma cells with an abundant hyaluronan-rich matrix. The results demonstrated that HAS-2 is the predominant HAS in MG-63. Accumulation of intracellular hyaluronan increased inmore » association with the proliferative phase of these cells. The selective inhibition of HAS-2 mRNA in MG-63 cells by antisense phosphorothioate oligonucleotides resulted in reduced hyaluronan accumulation by these cells. As expected, the reduction in hyaluronan disrupted the assembly of cell-associated matrices. However, of most interest, coincident with the reduction in hyaluronan, there was a substantial decrease in cell proliferation, a decrease in cell motility and a decrease in cell invasiveness. These data suggest that hyaluronan synthesized by HAS-2 in MG-63 plays a crucial role in osteosarcoma cell proliferation, motility, and invasion.« less

Chemical Activation of the Hypoxia-Inducible Factor Reversibly Reduces Tendon Stem Cell Proliferation, Inhibits Their Differentiation, and Maintains Cell Undifferentiation

PubMed Central

Creo, Pasquale; Bergante, Sonia; Conforti, Erika; Banfi, Giuseppe

2018-01-01

Adult stem cell-based therapeutic approaches for tissue regeneration have been proposed for several years. However, adult stem cells are usually limited in number and difficult to be expanded in vitro, and they usually tend to quickly lose their potency with passages, as they differentiate and become senescent. Culturing stem cells under reduced oxygen tensions (below 21%) has been proposed as a tool to increase cell proliferation, but many studies reported opposite effects. In particular, cell response to hypoxia seems to be very stem cell type specific. Nonetheless, it is clear that a major role in this process is played by the hypoxia inducible factor (HIF), the master regulator of cell response to oxygen deprivation, which affects cell metabolism and differentiation. Herein, we report that a chemical activation of HIF in human tendon stem cells reduces their proliferation and inhibits their differentiation in a reversible and dose-dependent manner. These results support the notion that hypoxia, by activating HIF, plays a crucial role in preserving stem cells in an undifferentiated state in the “hypoxic niches” present in the tissue in which they reside before migrating in more oxygenated areas to heal a damaged tissue. PMID:29713352

CD22 Promotes B-1b Cell Responses to T Cell-Independent Type 2 Antigens.

PubMed

Haas, Karen M; Johnson, Kristen L; Phipps, James P; Do, Cardinal

2018-03-01

CD22 (Siglec-2) is a critical regulator of B cell activation and survival. CD22 -/- mice generate significantly impaired Ab responses to T cell-independent type 2 (TI-2) Ags, including haptenated Ficoll and pneumococcal polysaccharides, Ags that elicit poor T cell help and activate BCR signaling via multivalent epitope crosslinking. This has been proposed to be due to impaired marginal zone (MZ) B cell development/maintenance in CD22 -/- mice. However, mice expressing a mutant form of CD22 unable to bind sialic acid ligands generated normal TI-2 Ab responses, despite significantly reduced MZ B cells. Moreover, mice treated with CD22 ligand-binding blocking mAbs, which deplete MZ B cells, had little effect on TI-2 Ab responses. We therefore investigated the effects of CD22 deficiency on B-1b cells, an innate-like B cell population that plays a key role in TI-2 Ab responses. B-1b cells from CD22 -/- mice had impaired BCR-induced proliferation and significantly increased intracellular Ca 2+ concentration responses following BCR crosslinking. Ag-specific B-1b cell expansion and plasmablast differentiation following TI-2 Ag immunization was significantly impaired in CD22 -/- mice, consistent with reduced TI-2 Ab responses. We generated CD22 -/- mice with reduced CD19 levels (CD22 -/- CD19 +/- ) to test the hypothesis that augmented B-1b cell BCR signaling in CD22 -/- mice contributes to impaired TI-2 Ab responses. BCR-induced proliferation and intracellular Ca 2+ concentration responses were normalized in CD22 -/- CD19 +/- B-1b cells. Consistent with this, TI-2 Ag-specific B-1b cell expansion, plasmablast differentiation, survival, and Ab responses were rescued in CD22 -/- CD19 +/- mice. Thus, CD22 plays a critical role in regulating TI-2 Ab responses through regulating B-1b cell signaling thresholds. Copyright © 2018 by The American Association of Immunologists, Inc.

Human T-cell leukemia virus type 1 Tax oncoprotein represses the expression of the BCL11B tumor suppressor in T-cells.

PubMed

Takachi, Takayuki; Takahashi, Masahiko; Takahashi-Yoshita, Manami; Higuchi, Masaya; Obata, Miki; Mishima, Yukio; Okuda, Shujiro; Tanaka, Yuetsu; Matsuoka, Masao; Saitoh, Akihiko; Green, Patrick L; Fujii, Masahiro

2015-04-01

Human T-cell leukemia virus type 1 (HTLV-1) is the etiological agent of adult T cell leukemia (ATL), which is an aggressive form of T-cell malignancy. HTLV-1 oncoproteins, Tax and HBZ, play crucial roles in the immortalization of T-cells and/or leukemogenesis by dysregulating the cellular functions in the host. Recent studies show that HTLV-1-infected T-cells have reduced expression of the BCL11B tumor suppressor protein. In the present study, we explored whether Tax and/or HBZ play a role in downregulating BCL11B in HTLV-1-infected T-cells. Lentiviral transduction of Tax in a human T-cell line repressed the expression of BCL11B at both the protein and mRNA levels, whereas the transduction of HBZ had little effect on the expression. Tax mutants with a decreased activity for the NF-κB, CREB or PDZ protein pathways still showed a reduced expression of the BCL11B protein, thereby implicating a different function of Tax in BCL11B downregulation. In addition, the HTLV-2 Tax2 protein reduced the BCL11B protein expression in T-cells. Seven HTLV-1-infected T-cell lines, including three ATL-derived cell lines, showed reduced BCL11B mRNA and protein expression relative to an uninfected T-cell line, and the greatest reductions were in the cells expressing Tax. Collectively, these results indicate that Tax is responsible for suppressing BCL11B protein expression in HTLV-1-infected T-cells; Tax-mediated repression of BCL11B is another mechanism that Tax uses to promote oncogenesis of HTLV-1-infected T-cells. © 2015 The Authors. Cancer Science published by Wiley Publishing Asia Pty Ltd on behalf of Japanese Cancer Association.

Deficiency of RgpG Causes Major Defects in Cell Division and Biofilm Formation, and Deficiency of LytR-CpsA-Psr Family Proteins Leads to Accumulation of Cell Wall Antigens in Culture Medium by Streptococcus mutans.

PubMed

De, Arpan; Liao, Sumei; Bitoun, Jacob P; Roth, Randy; Beatty, Wandy L; Wu, Hui; Wen, Zezhang T

2017-09-01

Streptococcus mutans is known to possess rhamnose-glucose polysaccharide (RGP), a major cell wall antigen. S. mutans strains deficient in rgpG , encoding the first enzyme of the RGP biosynthesis pathway, were constructed by allelic exchange. The rgpG deficiency had no effect on growth rate but caused major defects in cell division and altered cell morphology. Unlike the coccoid wild type, the rgpG mutant existed primarily in chains of swollen, "squarish" dividing cells. Deficiency of rgpG also causes significant reduction in biofilm formation ( P < 0.01). Double and triple mutants with deficiency in brpA and/or psr , genes coding for the LytR-CpsA-Psr family proteins BrpA and Psr, which were previously shown to play important roles in cell envelope biogenesis, were constructed using the rgpG mutant. There were no major differences in growth rates between the wild-type strain and the rgpG brpA and rgpG psr double mutants, but the growth rate of the rgpG brpA psr triple mutant was reduced drastically ( P < 0.001). Under transmission electron microscopy, both double mutants resembled the rgpG mutant, while the triple mutant existed as giant cells with multiple asymmetric septa. When analyzed by immunoblotting, the rgpG mutant displayed major reductions in cell wall antigens compared to the wild type, while little or no signal was detected with the double and triple mutants and the brpA and psr single mutants. These results suggest that RgpG in S. mutans plays a critical role in cell division and biofilm formation and that BrpA and Psr may be responsible for attachment of cell wall antigens to the cell envelope. IMPORTANCE Streptococcus mutans , a major etiological agent of human dental caries, produces rhamnose-glucose polysaccharide (RGP) as the major cell wall antigen. This study provides direct evidence that deficiency of RgpG, the first enzyme of the RGP biosynthesis pathway, caused major defects in cell division and morphology and reduced biofilm formation by S. mutans , indicative of a significant role of RGP in cell division and biofilm formation in S. mutans These results are novel not only in S. mutans , but also other streptococci that produce RGP. This study also shows that the LytR-CpsA-Psr family proteins BrpA and Psr in S. mutans are involved in attachment of RGP and probably other cell wall glycopolymers to the peptidoglycan. In addition, the results also suggest that BrpA and Psr may play a direct role in cell division and biofilm formation in S. mutans This study reveals new potential targets to develop anticaries therapeutics. Copyright © 2017 American Society for Microbiology.

The antiproliferative effect of acridone alkaloids on several cancer cell lines.

PubMed

Kawaii, S; Tomono, Y; Katase, E; Ogawa, K; Yano, M; Takemura, Y; Ju-ichi, M; Ito, C; Furukawa, H

1999-04-01

Fifteen acridone alkaloids were examined for their antiproliferative activity toward monolayers and suspension of several types of cancer and normal human cell lines. As a result, atalaphyllidine (9), 5-hydroxy-N-methylseverifoline (11), atalaphyllinine (12), and des-N-methylnoracronycine (13) showed potent antiproliferative activity against tumor cell lines, whereas they have weak cytotoxicity on normal human cell lines. The structure-activity relationship established from the results revealed that a secondary amine, hydroxyl groups at C-1 and C-5, and a prenyl group at C-2 played an important role for antiproliferative activities of the tetracyclic acridones.

Probing the Role of Nascent Helicity in p27 Function as a Cell Cycle Regulator

PubMed Central

Otieno, Steve; Kriwacki, Richard

2012-01-01

p27 regulates the activity of Cdk complexes which are the principal governors of phase transitions during cell division. Members of the p27 family of proteins, which also includes p21 and p57, are called the Cip/Kip cyclin-dependent kinase regulators (CKRs). Interestingly, the Cip/Kip CKRs play critical roles in cell cycle regulation by being intrinsically unstructured, a characteristic contrary to the classical structure-function paradigm. They exhibit nascent helicity which has been localized to a segment referred to as sub-domain LH. The nascent helicity of this sub-domain is conserved and we hypothesize that it is an important determinant of their functional properties. To test this hypothesis, we successfully designed and prepared p27 variants in which domain LH was either more or less helical with respect to the wild-type protein. Thermal denaturation experiments showed that the ternary complexes of the p27 variants bound to Cdk2/Cyclin A were less stable compared to the wild-type complex. Isothermal titration calorimetry experiments showed a decrease in the enthalpy of binding for all the mutants with respect to p27. The free energies of binding varied within a much narrower range. In vitro Cdk2 inhibition assays showed that the p27 variants exhibited disparate inhibitory potencies. Furthermore, when over-expressed in NIH 3T3 mouse fibroblast cells, the less helical p27 variants were less effective in causing cell cycle arrest relative to the wild-type p27. Our results indicate that the nascent helicity of sub-domain LH plays a key role mediating the biological function of p27. PMID:23071750

Evolutionary divergence and functions of the human interleukin (IL) gene family

PubMed Central

2010-01-01

Cytokines play a very important role in nearly all aspects of inflammation and immunity. The term 'interleukin' (IL) has been used to describe a group of cytokines with complex immunomodulatory functions -- including cell proliferation, maturation, migration and adhesion. These cytokines also play an important role in immune cell differentiation and activation. Determining the exact function of a particular cytokine is complicated by the influence of the producing cell type, the responding cell type and the phase of the immune response. ILs can also have pro- and anti-inflammatory effects, further complicating their characterisation. These molecules are under constant pressure to evolve due to continual competition between the host's immune system and infecting organisms; as such, ILs have undergone significant evolution. This has resulted in little amino acid conservation between orthologous proteins, which further complicates the gene family organisation. Within the literature there are a number of overlapping nomenclature and classification systems derived from biological function, receptor-binding properties and originating cell type. Determining evolutionary relationships between ILs therefore can be confusing. More recently, crystallographic data and the identification of common structural motifs have led to a more accurate classification system. To date, the known ILs can be divided into four major groups based on distinguishing structural features. These groups include the genes encoding the IL1-like cytokines, the class I helical cytokines (IL4-like, γ-chain and IL6/12-like), the class II helical cytokines (IL10-like and IL28-like) and the IL17-like cytokines. In addition, there are a number of ILs that do not fit into any of the above groups, due either to their unique structural features or lack of structural information. This suggests that the gene family organisation may be subject to further change in the near future. PMID:21106488

Vitamin D enhances omega-3 polyunsaturated fatty acids-induced apoptosis in breast cancer cells.

PubMed

Yang, Jing; Zhu, Shenglong; Lin, Guangxiao; Song, Ci; He, Zhao

2017-08-01

Breast cancer is a leading type of cancer in women and generally classified into three subtypes of ER + /PR + , HER2 + and triple negative. Both omega-3 polyunsaturated fatty acids and vitamin D 3 play positive role in the reduction of breast cancer incidence. However, whether combination of omega-3 polyunsaturated fatty acids and vitamin D 3 has stronger protective effect on breast carcinogenesis still remains unknown. In this study, we show that the combination of ω-3 free fatty acids (ω-3 FFAs) and 1α, 25-dihydroxy-vitamin D 3 (VD 3 ) dramatically enhances cell apoptosis among three subtypes of breast cancer cell lines. Bcl-2 and total PARP protein levels are decreased in combined treatment MCF-7 and SK-BR-3 cells. Caspase signals play a vital role in cell apoptosis induced by combination. Moreover, Raf-MAPK signaling pathway is involved in the apoptosis induction by combination of ω-3 FFAs+VD 3 . These results demonstrate that the induction of cell apoptosis by combined treatment is dependent on different signaling pathways in three subtypes of breast cancer cell lines. © 2017 International Federation for Cell Biology.

CCL3 Enhances Antitumor Immune Priming in the Lymph Node via IFNγ with Dependency on Natural Killer Cells

PubMed Central

Allen, Frederick; Rauhe, Peter; Askew, David; Tong, Alexander A.; Nthale, Joseph; Eid, Saada; Myers, Jay T.; Tong, Caryn; Huang, Alex Y.

2017-01-01

Lymph node (LN) plays a critical role in tumor cell survival outside of the primary tumor sites and dictates overall clinical response in many tumor types (1, 2). Previously, we and others have demonstrated that CCL3 plays an essential role in orchestrating T cell—antigen-presenting cell (APC) encounters in the draining LN following vaccination, and such interactions enhance the magnitude of the memory T cell pool (3–5). In the current study, we investigate the cellular responses in the tumor-draining lymph nodes (TDLNs) of a CCL3-secreting CT26 colon tumor (L3TU) as compared to wild-type tumor (WTTU) during the priming phase of an antitumor response (≤10 days). In comparison to WTTU, inoculation of L3TU resulted in suppressed tumor growth, a phenomenon that is accompanied by altered in vivo inflammatory responses on several fronts. Autologous tumor-derived CCL3 (aCCL3) secretion by L3TU bolstered the recruitment of T- and B-lymphocytes, tissue-migratory CD103+ dendritic cells (DCs), and CD49b+ natural killer (NK) cells, resulting in significant increases in the differentiation and activation of multiple Interferon-gamma (IFNγ)-producing leukocytes in the TDLN. During this early phase of immune priming, NK cells constitute the major producers of IFNγ in the TDLN. CCL3 also enhances CD8+ T cell proliferation and differentiation by augmenting DC capacity to drive T cell activation in the TDLN. Our results revealed that CCL3-dependent IFNγ production and CCL3-induced DC maturation drive the priming of effective antitumor immunity in the TDLN. PMID:29109732

Collagen Scaffolds in Bone Sialoprotein-Mediated Bone Regeneration

PubMed Central

Kruger, Thomas E.; Miller, Andrew H.; Wang, Jinxi

2013-01-01

Decades of research in bioengineering have resulted in the development of many types of 3-dimentional (3D) scaffolds for use as drug delivery systems (DDS) and for tissue regeneration. Scaffolds may be comprised of different natural fibers and synthetic polymers as well as ceramics in order to exert the most beneficial attributes including biocompatibility, biodegradability, structural integrity, cell infiltration and attachment, and neovascularization. Type I collagen scaffolds meet most of these criteria. In addition, type I collagen binds integrins through RGD and non-RGD sites which facilitates cell migration, attachment, and proliferation. Type I collagen scaffolds can be used for bone tissue repair when they are coated with osteogenic proteins such as bone morphogenic protein (BMP) and bone sialoprotein (BSP). BSP, a small integrin-binding ligand N-linked glycoprotein (SIBLING), has osteogenic properties and plays an essential role in bone formation. BSP also mediates mineral deposition, binds type I collagen with high affinity, and binds αvβ 3 and αvβ 5 integrins which mediate cell signaling. This paper reviews the emerging evidence demonstrating the efficacy of BSP-collagen scaffolds in bone regeneration. PMID:23653530

Collagen scaffolds in bone sialoprotein-mediated bone regeneration.

PubMed

Kruger, Thomas E; Miller, Andrew H; Wang, Jinxi

2013-01-01

Decades of research in bioengineering have resulted in the development of many types of 3-dimentional (3D) scaffolds for use as drug delivery systems (DDS) and for tissue regeneration. Scaffolds may be comprised of different natural fibers and synthetic polymers as well as ceramics in order to exert the most beneficial attributes including biocompatibility, biodegradability, structural integrity, cell infiltration and attachment, and neovascularization. Type I collagen scaffolds meet most of these criteria. In addition, type I collagen binds integrins through RGD and non-RGD sites which facilitates cell migration, attachment, and proliferation. Type I collagen scaffolds can be used for bone tissue repair when they are coated with osteogenic proteins such as bone morphogenic protein (BMP) and bone sialoprotein (BSP). BSP, a small integrin-binding ligand N-linked glycoprotein (SIBLING), has osteogenic properties and plays an essential role in bone formation. BSP also mediates mineral deposition, binds type I collagen with high affinity, and binds α v β 3 and α v β 5 integrins which mediate cell signaling. This paper reviews the emerging evidence demonstrating the efficacy of BSP-collagen scaffolds in bone regeneration.

How Follicular Dendritic Cells Shape the B-Cell Antigenome

PubMed Central

Kranich, Jan; Krautler, Nike Julia

2016-01-01

Follicular dendritic cells (FDCs) are stromal cells residing in primary follicles and in germinal centers of secondary and tertiary lymphoid organs (SLOs and TLOs). There, they play a crucial role in B-cell activation and affinity maturation of antibodies. FDCs have the unique capacity to bind and retain native antigen in B-cell follicles for long periods of time. Therefore, FDCs shape the B-cell antigenome (the sum of all B-cell antigens) in SLOs and TLOs. In this review, we discuss recent findings that explain how this stromal cell type can arise in almost any tissue during TLO formation and, furthermore, focus on the mechanisms of antigen capture and retention involved in the generation of long-lasting antigen depots displayed on FDCs. PMID:27446069

Deep Learning Automates the Quantitative Analysis of Individual Cells in Live-Cell Imaging Experiments.

PubMed

Van Valen, David A; Kudo, Takamasa; Lane, Keara M; Macklin, Derek N; Quach, Nicolas T; DeFelice, Mialy M; Maayan, Inbal; Tanouchi, Yu; Ashley, Euan A; Covert, Markus W

2016-11-01

Live-cell imaging has opened an exciting window into the role cellular heterogeneity plays in dynamic, living systems. A major critical challenge for this class of experiments is the problem of image segmentation, or determining which parts of a microscope image correspond to which individual cells. Current approaches require many hours of manual curation and depend on approaches that are difficult to share between labs. They are also unable to robustly segment the cytoplasms of mammalian cells. Here, we show that deep convolutional neural networks, a supervised machine learning method, can solve this challenge for multiple cell types across the domains of life. We demonstrate that this approach can robustly segment fluorescent images of cell nuclei as well as phase images of the cytoplasms of individual bacterial and mammalian cells from phase contrast images without the need for a fluorescent cytoplasmic marker. These networks also enable the simultaneous segmentation and identification of different mammalian cell types grown in co-culture. A quantitative comparison with prior methods demonstrates that convolutional neural networks have improved accuracy and lead to a significant reduction in curation time. We relay our experience in designing and optimizing deep convolutional neural networks for this task and outline several design rules that we found led to robust performance. We conclude that deep convolutional neural networks are an accurate method that require less curation time, are generalizable to a multiplicity of cell types, from bacteria to mammalian cells, and expand live-cell imaging capabilities to include multi-cell type systems.

Deep Learning Automates the Quantitative Analysis of Individual Cells in Live-Cell Imaging Experiments

DOE PAGES

Van Valen, David A.; Kudo, Takamasa; Lane, Keara M.; ...

2016-11-04

Live-cell imaging has opened an exciting window into the role cellular heterogeneity plays in dynamic, living systems. A major critical challenge for this class of experiments is the problem of image segmentation, or determining which parts of a microscope image correspond to which individual cells. Current approaches require many hours of manual curation and depend on approaches that are difficult to share between labs. They are also unable to robustly segment the cytoplasms of mammalian cells. Here, we show that deep convolutional neural networks, a supervised machine learning method, can solve this challenge for multiple cell types across the domainsmore » of life. We demonstrate that this approach can robustly segment fluorescent images of cell nuclei as well as phase images of the cytoplasms of individual bacterial and mammalian cells from phase contrast images without the need for a fluorescent cytoplasmic marker. These networks also enable the simultaneous segmentation and identification of different mammalian cell types grown in co-culture. A quantitative comparison with prior methods demonstrates that convolutional neural networks have improved accuracy and lead to a significant reduction in curation time. We relay our experience in designing and optimizing deep convolutional neural networks for this task and outline several design rules that we found led to robust performance. We conclude that deep convolutional neural networks are an accurate method that require less curation time, are generalizable to a multiplicity of cell types, from bacteria to mammalian cells, and expand live-cell imaging capabilities to include multi-cell type systems.« less

Deep Learning Automates the Quantitative Analysis of Individual Cells in Live-Cell Imaging Experiments

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

Van Valen, David A.; Kudo, Takamasa; Lane, Keara M.

Live-cell imaging has opened an exciting window into the role cellular heterogeneity plays in dynamic, living systems. A major critical challenge for this class of experiments is the problem of image segmentation, or determining which parts of a microscope image correspond to which individual cells. Current approaches require many hours of manual curation and depend on approaches that are difficult to share between labs. They are also unable to robustly segment the cytoplasms of mammalian cells. Here, we show that deep convolutional neural networks, a supervised machine learning method, can solve this challenge for multiple cell types across the domainsmore » of life. We demonstrate that this approach can robustly segment fluorescent images of cell nuclei as well as phase images of the cytoplasms of individual bacterial and mammalian cells from phase contrast images without the need for a fluorescent cytoplasmic marker. These networks also enable the simultaneous segmentation and identification of different mammalian cell types grown in co-culture. A quantitative comparison with prior methods demonstrates that convolutional neural networks have improved accuracy and lead to a significant reduction in curation time. We relay our experience in designing and optimizing deep convolutional neural networks for this task and outline several design rules that we found led to robust performance. We conclude that deep convolutional neural networks are an accurate method that require less curation time, are generalizable to a multiplicity of cell types, from bacteria to mammalian cells, and expand live-cell imaging capabilities to include multi-cell type systems.« less

Deep Learning Automates the Quantitative Analysis of Individual Cells in Live-Cell Imaging Experiments

PubMed Central

Van Valen, David A.; Lane, Keara M.; Quach, Nicolas T.; Maayan, Inbal

2016-01-01

Live-cell imaging has opened an exciting window into the role cellular heterogeneity plays in dynamic, living systems. A major critical challenge for this class of experiments is the problem of image segmentation, or determining which parts of a microscope image correspond to which individual cells. Current approaches require many hours of manual curation and depend on approaches that are difficult to share between labs. They are also unable to robustly segment the cytoplasms of mammalian cells. Here, we show that deep convolutional neural networks, a supervised machine learning method, can solve this challenge for multiple cell types across the domains of life. We demonstrate that this approach can robustly segment fluorescent images of cell nuclei as well as phase images of the cytoplasms of individual bacterial and mammalian cells from phase contrast images without the need for a fluorescent cytoplasmic marker. These networks also enable the simultaneous segmentation and identification of different mammalian cell types grown in co-culture. A quantitative comparison with prior methods demonstrates that convolutional neural networks have improved accuracy and lead to a significant reduction in curation time. We relay our experience in designing and optimizing deep convolutional neural networks for this task and outline several design rules that we found led to robust performance. We conclude that deep convolutional neural networks are an accurate method that require less curation time, are generalizable to a multiplicity of cell types, from bacteria to mammalian cells, and expand live-cell imaging capabilities to include multi-cell type systems. PMID:27814364

Different role of zinc transporter 8 between type 1 diabetes mellitus and type 2 diabetes mellitus.

PubMed

Yi, Bo; Huang, Gan; Zhou, Zhiguang

2016-07-01

Diabetes can be simply classified into type 1 diabetes mellitus and type 2 diabetes mellitus. Zinc transporter 8 (ZnT8), a novel islet autoantigen, is specifically expressed in insulin-containing secretory granules of β-cells. Genetic studies show that the genotypes of SLC30A8 can determine either protective or diabetogenic response depending on environmental and lifestyle factors. The ZnT8 protein expression, as well as zinc content in β-cells, was decreased in diabetic mice. Thus, ZnT8 might participate in insulin biosynthesis and release, and subsequently involved deteriorated β-cell function through direct or indirect mechanisms in type 1 diabetes mellitus and type 2 diabetes mellitus. From a clinical feature standpoint, the prevalence of ZnT8A is gradiently increased in type 2 diabetes mellitus, latent autoimmune diabetes in adults and type 1 diabetes mellitus. The frequency and epitopes of ZnT8-specific T cells and cytokine release by ZnT8-specific T cells are also different in diabetic patients and healthy controls. Additionally, the response to ZnT8 administration is also different in type 1 diabetes mellitus and type 2 diabetes mellitus. In the present review, we summarize the literature about clinical aspects of ZnT8 in the pathogenesis of diabetes, and suggest that ZnT8 might play a different role between type 1 diabetes mellitus and type 2 diabetes mellitus. © 2015 The Authors. Journal of Diabetes Investigation published by Asian Association for the Study of Diabetes (AASD) and John Wiley & Sons Australia, Ltd.

Membrane microparticles and diseases.

PubMed

Wu, Z-H; Ji, C-L; Li, H; Qiu, G-X; Gao, C-J; Weng, X-S

2013-09-01

Membrane microparticles (MPs) are plasma membrane-derived vesicles shed by various types of activated or apoptotic cells including platelets, monocytes, endothelial cells, red blood cells, and granulocytes. MPs are being increasingly recognized as important regulators of cell-to-cell interactions. Recent evidences suggest they may play important functions not only in homeostasis but also in the pathogenesis of a number of diseases such as vascular diseases, cancer, infectious diseases and diabetes mellitus. Accordingly, inhibiting the production of MPs may serve as a novel therapeutic strategy for these diseases. Here we review recent advances on the mechanism underlying the generation of MPs and the role of MPs in vascular diseases, cancer, diabetes, inflammation, and pathogen infection.

Bax and Bak are required for apoptosis induction by sulforaphane, a cruciferous vegetable-derived cancer chemopreventive agent.

PubMed

Choi, Sunga; Singh, Shivendra V

2005-03-01

Sulforaphane, a constituent of many edible cruciferous vegetables, including broccoli, effectively suppresses proliferation of cancer cells in culture and in vivo by causing apoptosis induction, but the sequence of events leading to cell death is poorly defined. Here, we show that multidomain proapoptotic Bcl-2 family members Bax and Bak play a critical role in apoptosis induction by sulforaphane. This conclusion is based on the following observations: (a) sulforaphane treatment caused a dose- and time-dependent increase in the protein levels of both Bax and Bak and conformational change and mitochondrial translocation of Bax in SV40-transformed mouse embryonic fibroblasts (MEF) derived from wild-type mice to trigger cytosolic release of apoptogenic molecules (cytochrome c and Smac/DIABLO), activation of caspase-9 and caspase-3, and ultimately cell death; (b) MEFs derived from Bax or Bak knockout mice resisted cell death by sulforaphane, and (c) MEFs derived from Bax and Bak double knockout mice exhibited even greater protection against sulforaphane-induced cytochrome c release, caspase activation, and apoptosis compared with wild-type or single knockout cells. Interestingly, sulforaphane treatment also caused a dose- and time-dependent increase in the protein level of Apaf-1 in wild-type, Bax-/-, and Bak-/- MEFs but not in double knockout, suggesting that Bax and Bak might regulate sulforaphane-mediated induction of Apaf-1 protein. A marked decline in the protein level of X-linked inhibitor of apoptosis on treatment with sulforaphane was also observed. Thus, it is reasonable to postulate that sulforaphane-induced apoptosis is amplified by a decrease in X-linked inhibitor of apoptosis level, which functions to block cell death by inhibiting activities of caspases. In conclusion, the results of the present study indicate that Bax and Bak proteins play a critical role in initiation of cell death by sulforaphane.

Regucalcin and cell regulation: role as a suppressor protein in signal transduction.

PubMed

Yamaguchi, Masayoshi

2011-07-01

Regucalcin was discovered in 1978 as a calcium-binding protein that does not contain EF-hand motif of calcium-binding domain (Yamaguchi and Yamamoto Chem Pharm Bull 26:1915-1918, 1978). The name regucalcin was proposed for this calcium-binding protein, which can regulate various Ca(2+)-dependent enzyme activations in liver cells. The regucalcin gene is localized on the chromosome X, and the organization of the regucalcin gene consists of seven exons and six introns. AP-1, NF1-A1, and RGPR-p117 bind to the promoter region of the rat regucalcin gene and enhance transcription activity of regucalcin gene expression that is mediated through calcium signaling. Regucalcin plays a pivotal role in the keep of intracellular calcium ion (Ca(2+)) homeostasis due to activating Ca(2+) pump enzymes in the plasma membrane (basolateral membrane), microsomes (endoplasmic reticulum), mitochondria, and nuclei of many cell types. Regucalcin has a suppressive effect on calcium signaling from the cytoplasm to the nucleus in the proliferative cells. Regucalcin has also been demonstrated to transport to the nucleus, and it can inhibit Ca(2+)-dependent protein kinase and protein phosphatase activities, Ca(2+)-activated deoxyribonucleic acid (DNA) fragmentation, and DNA and ribonucleic acid (RNA) synthesis in the nucleus. Overexpression of regucalcin suppresses cell death and apoptosis in the cloned rat hepatoma cells induced by various signaling factors. Regucalcin can inhibit the enhancement of cell proliferation due to hormonal stimulation. Regucalcin plays an important role as a regulatory protein in cell signaling system, and it is proposed to play a pivotal role in keep of cell homeostasis and function.

Does IFN-γ play a role on the pathogenesis of non-atopic asthma in Latin America children?

PubMed

Figueiredo, Camila Alexandrina; Rodrigues, Laura Cunha; Alcantara-Neves, Neuza Maria; Cooper, Philip J; Amorim, Leila Denise; Silva, Nivea Bispo; Cruz, Alvaro A; Barreto, Mauricio Lima

2012-12-19

In this work we explore differences in blood cells and cytokine profiles in children according to atopic status and asthma (atopic or non-atopic). The study involved measurement of Th1(IFN-γ) and Th2 (IL-5 and IL-13) cytokines in Dermatophagoides pteronyssinus stimulated peripheral blood leukocytes, blood cell count, skin prick test and specific IgE against common aeroallergens. Atopic status was associated with eosinophilia and production of Th2 type cytokines. Atopic asthma was associated with eosinophilia and non-atopic asthma was associated with IFN-γ and elevated monocytes in blood. IFN-γ and monocytes might play a role in immunopathology of non-atopic asthma in Latin American children.

Role of Co-Sensitizers in Dye-Sensitized Solar Cells.

PubMed

Krishna, Narra Vamsi; Krishna, Jonnadula Venkata Suman; Mrinalini, Madoori; Prasanthkumar, Seelam; Giribabu, Lingamallu

2017-12-08

Co-sensitization is a popular route towards improved efficiency and stability of dye-sensitized solar cells (DSSCs). In this context, the power conversion efficiency (PCE) values of DSSCs incorporating Ru- and porphyrin-based dyes can be improved from 8-11 % to 11-14 % after the addition of additives, co-adsorbents, and co-sensitizers that reduce aggregation and charge recombination in the device. Among the three supporting material types, co-sensitizers play a major role to enhance the performance and stability of DSSCs, which is requried for commercialization. In this Minireview, we highlight the role co-sensitizers play in improving photovoltaic performance of devices containing Ru- and porphyrin-based sensitizers. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Truncated tyrosine kinase B brain-derived neurotrophic factor receptor directs cortical neural stem cells to a glial cell fate by a novel signaling mechanism.

PubMed

Cheng, Aiwu; Coksaygan, Turhan; Tang, Hongyan; Khatri, Rina; Balice-Gordon, Rita J; Rao, Mahendra S; Mattson, Mark P

2007-03-01

During development of the mammalian cerebral cortex neural stem cells (NSC) first generate neurons and subsequently produce glial cells. The mechanism(s) responsible for this developmental shift from neurogenesis to gliogenesis is unknown. Brain-derived neurotrophic factor (BDNF) is believed to play important roles in the development of the mammalian cerebral cortex; it enhances neurogenesis and promotes the differentiation and survival of newly generated neurons. Here, we provide evidence that a truncated form of the BDNF receptor tyrosine kinase B (trkB-t) plays a pivotal role in directing embryonic mouse cortical NSC to a glial cell fate. Expression of trkB-t promotes differentiation of NSC toward astrocytes while inhibiting neurogenesis both in cell culture and in vivo. The mechanism by which trkB-t induces astrocyte genesis is not simply the result of inhibition of full-length receptor with intrinsic tyrosine kinase activity signaling. Instead, binding of BDNF to trkB-t activates a signaling pathway (involving a G-protein and protein kinase C) that induced NSC to become glial progenitors and astrocytes. Thus, the increased expression of trkB-t in the embryonic cerebral cortex that occurs coincident with astrocyte production plays a pivotal role in the developmental transition from neurogenesis to gliogenesis. Our findings suggest a mechanism by which a single factor (BDNF) regulates the production of the two major cell types in the mammalian cerebral cortex.

Identification of Wnt Pathway Target Genes Regulating the Division and Differentiation of Larval Seam Cells and Vulval Precursor Cells in Caenorhabditis elegans.

PubMed

Gorrepati, Lakshmi; Krause, Michael W; Chen, Weiping; Brodigan, Thomas M; Correa-Mendez, Margarita; Eisenmann, David M

2015-06-05

The evolutionarily conserved Wnt/β-catenin signaling pathway plays a fundamental role during metazoan development, regulating numerous processes including cell fate specification, cell migration, and stem cell renewal. Wnt ligand binding leads to stabilization of the transcriptional effector β-catenin and upregulation of target gene expression to mediate a cellular response. During larval development of the nematode Caenorhabditis elegans, Wnt/β-catenin pathways act in fate specification of two hypodermal cell types, the ventral vulval precursor cells (VPCs) and the lateral seam cells. Because little is known about targets of the Wnt signaling pathways acting during larval VPC and seam cell differentiation, we sought to identify genes regulated by Wnt signaling in these two hypodermal cell types. We conditionally activated Wnt signaling in larval animals and performed cell type-specific "mRNA tagging" to enrich for VPC and seam cell-specific mRNAs, and then used microarray analysis to examine gene expression compared to control animals. Two hundred thirty-nine genes activated in response to Wnt signaling were identified, and we characterized 50 genes further. The majority of these genes are expressed in seam and/or vulval lineages during normal development, and reduction of function for nine genes caused defects in the proper division, fate specification, fate execution, or differentiation of seam cells and vulval cells. Therefore, the combination of these techniques was successful at identifying potential cell type-specific Wnt pathway target genes from a small number of cells and at increasing our knowledge of the specification and behavior of these C. elegans larval hypodermal cells. Copyright © 2015 Gorrepati et al.

Expression analysis of Arabidopsis vacuolar sorting receptor 3 reveals a putative function in guard cells.

PubMed

Avila, Emily L; Brown, Michelle; Pan, Songqin; Desikan, Radhika; Neill, Steven J; Girke, Thomas; Surpin, Marci; Raikhel, Natasha V

2008-01-01

Vacuolar sorting receptors (VSRs) are responsible for the proper targeting of soluble cargo proteins to their destination compartments. The Arabidopsis genome encodes seven VSRs. In this work, the spatio-temporal expression of one of the members of this gene family, AtVSR3, was determined by RT-PCR and promoter::reporter gene fusions. AtVSR3 was expressed specifically in guard cells. Consequently, a reverse genetics approach was taken to determine the function of AtVSR3 by using RNA interference (RNAi) technology. Plants expressing little or no AtVSR3 transcript had a compressed life cycle, bolting approximately 1 week earlier and senescing up to 2 weeks earlier than the wild-type parent line. While the development and distribution of stomata in AtVSR3 RNAi plants appeared normal, stomatal function was altered. The guard cells of mutant plants did not close in response to abscisic acid treatment, and the mean leaf temperatures of the RNAi plants were on average 0.8 degrees C lower than both wild type and another vacuolar sorting receptor mutant, atvsr1-1. Furthermore, the loss of AtVSR3 protein caused the accumulation of nitric oxide and hydrogen peroxide, signalling molecules implicated in the regulation of stomatal opening and closing. Finally, proteomics and western blot analyses of cellular proteins isolated from wild-type and AtVSR3 RNAi leaves showed that phospholipase Dgamma, which may play a role in abscisic acid signalling, accumulated to higher levels in AtVSR3 RNAi guard cells. Thus, AtVSR3 may play an important role in responses to plant stress.

Role of Chemokines and Trafficking of Immune Cells in Parasitic Infections

PubMed Central

McGovern, Kathryn E.; Wilson, Emma H.

2014-01-01

Parasites are diverse eukaryotic pathogens that can have complex life cycles. Their clearance, or control within a mammalian host requires the coordinated effort of the immune system. The cell types recruited to areas of infection can combat the disease, promote parasite replication and survival, or contribute to disease pathology. Location and timing of cell recruitment can be crucial. In this review, we explore the role chemokines play in orchestrating and balancing the immune response to achieve optimal control of parasite replication without promoting pathology. PMID:25383073

Derepression of nitrogenase activity in glutamine auxotrophs of Rhodopseudomonas capsulata.

PubMed Central

Wall, J D; Gest, H

1979-01-01

In contrast to wild-type cells, glutamine auxotrophs of the photosynthetic bacterium Rhodopseudomonas capsulata synthesize nitrogenase, produce H2 (catalyzed by nitrogenase), and continue to reduce dinitrogen to ammonia in the presence of exogenous NH4+. The glutamine synthetase activity of such mutants is less than 2% of that observed in the wild type. It appears that glutamine synthetase plays a significant role in regulation of nitrogenase synthesis in R. capsulata. PMID:35518

Characterization of TLX expression in neural stem cells and progenitor cells in adult brains.

PubMed

Li, Shengxiu; Sun, Guoqiang; Murai, Kiyohito; Ye, Peng; Shi, Yanhong

2012-01-01

TLX has been shown to play an important role in regulating the self-renewal and proliferation of neural stem cells in adult brains. However, the cellular distribution of endogenous TLX protein in adult brains remains to be elucidated. In this study, we used immunostaining with a TLX-specific antibody to show that TLX is expressed in both neural stem cells and transit-amplifying neural progenitor cells in the subventricular zone (SVZ) of adult mouse brains. Then, using a double thymidine analog labeling approach, we showed that almost all of the self-renewing neural stem cells expressed TLX. Interestingly, most of the TLX-positive cells in the SVZ represented the thymidine analog-negative, relatively quiescent neural stem cell population. Using cell type markers and short-term BrdU labeling, we demonstrated that TLX was also expressed in the Mash1+ rapidly dividing type C cells. Furthermore, loss of TLX expression dramatically reduced BrdU label-retaining neural stem cells and the actively dividing neural progenitor cells in the SVZ, but substantially increased GFAP staining and extended GFAP processes. These results suggest that TLX is essential to maintain the self-renewing neural stem cells in the SVZ and that the GFAP+ cells in the SVZ lose neural stem cell property upon loss of TLX expression. Understanding the cellular distribution of TLX and its function in specific cell types may provide insights into the development of therapeutic tools for neurodegenerative diseases by targeting TLX in neural stem/progenitors cells.

Characterization of TLX Expression in Neural Stem Cells and Progenitor Cells in Adult Brains

PubMed Central

Li, Shengxiu; Sun, Guoqiang; Murai, Kiyohito; Ye, Peng; Shi, Yanhong

2012-01-01

TLX has been shown to play an important role in regulating the self-renewal and proliferation of neural stem cells in adult brains. However, the cellular distribution of endogenous TLX protein in adult brains remains to be elucidated. In this study, we used immunostaining with a TLX-specific antibody to show that TLX is expressed in both neural stem cells and transit-amplifying neural progenitor cells in the subventricular zone (SVZ) of adult mouse brains. Then, using a double thymidine analog labeling approach, we showed that almost all of the self-renewing neural stem cells expressed TLX. Interestingly, most of the TLX-positive cells in the SVZ represented the thymidine analog-negative, relatively quiescent neural stem cell population. Using cell type markers and short-term BrdU labeling, we demonstrated that TLX was also expressed in the Mash1+ rapidly dividing type C cells. Furthermore, loss of TLX expression dramatically reduced BrdU label-retaining neural stem cells and the actively dividing neural progenitor cells in the SVZ, but substantially increased GFAP staining and extended GFAP processes. These results suggest that TLX is essential to maintain the self-renewing neural stem cells in the SVZ and that the GFAP+ cells in the SVZ lose neural stem cell property upon loss of TLX expression.Understanding the cellular distribution of TLX and its function in specific cell types may provide insights into the development of therapeutic tools for neurodegenerative diseases by targeting TLX in neural stem/progenitors cells. PMID:22952666

The neural stem cell fate determinant TLX promotes tumorigenesis and genesis of cells resembling glioma stem cells.

PubMed

Park, Hyo-Jung; Kim, Jun-Kyum; Jeon, Hye-Min; Oh, Se-Yeong; Kim, Sung-Hak; Nam, Do-Hyun; Kim, Hyunggee

2010-11-01

A growing body of evidence indicates that deregulation of stem cell fate determinants is a hallmark of many types of malignancies. The neural stem cell fate determinant TLX plays a pivotal role in neurogenesis in the adult brain by maintaining neural stem cells. Here, we report a tumorigenic role of TLX in brain tumor initiation and progression. Increased TLX expression was observed in a number of glioma cells and glioma stem cells, and correlated with poor survival of patients with gliomas. Ectopic expression of TLX in the U87MG glioma cell line and Ink4a/Arf-deficient mouse astrocytes (Ink4a/Arf(-/-) astrocytes) induced cell proliferation with a concomitant increase in cyclin D expression, and accelerated foci formation in soft agar and tumor formation in in vivo transplantation assays. Furthermore, overexpression of TLX in Ink4a/Arf(-/-) astrocytes inhibited cell migration and invasion and promoted neurosphere formation and Nestin expression, which are hallmark characteristics of glioma stem cells, under stem cell culture conditions. Our results indicate that TLX is involved in glioma stem cell genesis and represents a potential therapeutic target for this type of malignancy.

Subcellular Relocalization and Positive Selection Play Key Roles in the Retention of Duplicate Genes of Populus Class III Peroxidase Family[W][OPEN

PubMed Central

Ren, Lin-Ling; Liu, Yan-Jing; Liu, Hai-Jing; Qian, Ting-Ting; Qi, Li-Wang; Wang, Xiao-Ru; Zeng, Qing-Yin

2014-01-01

Gene duplication is the primary source of new genes and novel functions. Over the course of evolution, many duplicate genes lose their function and are eventually removed by deletion. However, some duplicates have persisted and evolved diverse functions. A particular challenge is to understand how this diversity arises and whether positive selection plays a role. In this study, we reconstructed the evolutionary history of the class III peroxidase (PRX) genes from the Populus trichocarpa genome. PRXs are plant-specific enzymes that play important roles in cell wall metabolism and in response to biotic and abiotic stresses. We found that two large tandem-arrayed clusters of PRXs evolved from an ancestral cell wall type PRX to vacuole type, followed by tandem duplications and subsequent functional specification. Substitution models identified seven positively selected sites in the vacuole PRXs. These positively selected sites showed significant effects on the biochemical functions of the enzymes. We also found that positive selection acts more frequently on residues adjacent to, rather than directly at, a critical active site of the enzyme, and on flexible regions rather than on rigid structural elements of the protein. Our study provides new insights into the adaptive molecular evolution of plant enzyme families. PMID:24934172

Cell Type-Specific Chromatin Signatures Underline Regulatory DNA Elements in Human Induced Pluripotent Stem Cells and Somatic Cells.

PubMed

Zhao, Ming-Tao; Shao, Ning-Yi; Hu, Shijun; Ma, Ning; Srinivasan, Rajini; Jahanbani, Fereshteh; Lee, Jaecheol; Zhang, Sophia L; Snyder, Michael P; Wu, Joseph C

2017-11-10

Regulatory DNA elements in the human genome play important roles in determining the transcriptional abundance and spatiotemporal gene expression during embryonic heart development and somatic cell reprogramming. It is not well known how chromatin marks in regulatory DNA elements are modulated to establish cell type-specific gene expression in the human heart. We aimed to decipher the cell type-specific epigenetic signatures in regulatory DNA elements and how they modulate heart-specific gene expression. We profiled genome-wide transcriptional activity and a variety of epigenetic marks in the regulatory DNA elements using massive RNA-seq (n=12) and ChIP-seq (chromatin immunoprecipitation combined with high-throughput sequencing; n=84) in human endothelial cells (CD31 + CD144 + ), cardiac progenitor cells (Sca-1 + ), fibroblasts (DDR2 + ), and their respective induced pluripotent stem cells. We uncovered 2 classes of regulatory DNA elements: class I was identified with ubiquitous enhancer (H3K4me1) and promoter (H3K4me3) marks in all cell types, whereas class II was enriched with H3K4me1 and H3K4me3 in a cell type-specific manner. Both class I and class II regulatory elements exhibited stimulatory roles in nearby gene expression in a given cell type. However, class I promoters displayed more dominant regulatory effects on transcriptional abundance regardless of distal enhancers. Transcription factor network analysis indicated that human induced pluripotent stem cells and somatic cells from the heart selected their preferential regulatory elements to maintain cell type-specific gene expression. In addition, we validated the function of these enhancer elements in transgenic mouse embryos and human cells and identified a few enhancers that could possibly regulate the cardiac-specific gene expression. Given that a large number of genetic variants associated with human diseases are located in regulatory DNA elements, our study provides valuable resources for deciphering the epigenetic modulation of regulatory DNA elements that fine-tune spatiotemporal gene expression in human cardiac development and diseases. © 2017 American Heart Association, Inc.

Wnt/β-Catenin Signaling in Liver Development, Homeostasis, and Pathobiology

PubMed Central

Russell, Jacquelyn O.; Monga, Satdarshan P.

2018-01-01

The liver is an organ that performs a multitude of functions, and its health is pertinent and indispensable to survival. Thus, the cellular and molecular machinery driving hepatic functions is of utmost relevance. The Wnt signaling pathway is one such signaling cascade that enables hepatic homeostasis and contributes to unique hepatic attributes such as metabolic zonation and regeneration. The Wnt/β-catenin pathway plays a role in almost every facet of liver biology. Furthermore, its aberrant activation is also a hallmark of various hepatic pathologies. In addition to its signaling function, β-catenin also plays a role at adherens junctions. Wnt/β-catenin signaling also influences the function of many different cell types. Due to this myriad of functions, Wnt/β-catenin signaling is complex, context-dependent, and highly regulated. In this review, we discuss the Wnt/β-catenin signaling pathway, its role in cell-cell adhesion and liver function, and the cell type–specific roles of Wnt/β-catenin signaling as it relates to liver physiology and pathobiology. PMID:29125798

Induction of apoptosis in rhabdomyosarcoma cells through down-regulation of PAX proteins

PubMed Central

Bernasconi, Michele; Remppis, Andrew; Fredericks, William J.; Rauscher, Frank J.; Schäfer, Beat W.

1996-01-01

The expression of a number of human paired box-containing (PAX) genes has been correlated with various types of tumors. Novel fusion genes encoding chimeric fusion proteins have been found in the pediatric malignant tumor alveolar rhabdomyosarcoma (RMS). They are generated by two chromosomal translocations t(2;13) and t(1;13) juxtaposing PAX3 or PAX7, respectively, with a forkhead domain gene FKHR. Here we describe that specific down-regulation of the t(2;13) translocation product in alveolar RMS cells by antisense oligonucleotides results in reduced cellular viability. Cells of embryonal RMS, the other major histiotype of this tumor, were found to express either wild type PAX3 or PAX7 at elevated levels when compared with primary human myoblasts. Treatment of corresponding embryonal RMS cells with antisense olignucleotides directed against the mRNA translational start site of either one of these two transcription factors similarly triggers cell death, which is most likely due to induction of apoptosis. Retroviral mediated ectopic expression of mouse Pax3 in a PAX7 expressing embryonal RMS cell line could partially rescue antisense induced apoptosis. These data suggest that the PAX3/FKHR fusion gene and wild-type PAX genes play a causative role in the formation of RMS and presumably other tumor types, possibly by suppressing the apoptotic program that would normally eliminate these cells. PMID:8917562

A co-culture system with three different primary human cell populations reveals that biomaterials and MSC modulate macrophage-driven fibroblast recruitment.

PubMed

Caires, Hugo R; Barros da Silva, Patrícia; Barbosa, Mário A; Almeida, Catarina R

2018-03-01

The biological response to implanted biomaterials is a complex and highly coordinated phenomenon involving many different cell types that interact within 3D microenvironments. Here, we increased the complexity of a 3D platform to include at least 3 cell types that play a role in the host response upon scaffold implantation. With this system, it was possible to address how immune responses triggered by 3D biomaterials mediate recruitment of stromal cells that promote tissue regeneration, mesenchymal stromal/stem cells (MSC), or a foreign body response, fibroblasts. Primary human macrophages yielded the highest fibroblast recruitment when interacting with chitosan scaffolds but not polylactic acid. Interestingly, when there were MSC and fibroblasts in the same environment, macrophages in chitosan scaffolds again promoted a significant increase on fibroblast recruitment, but not of MSC. However, macrophages that were firstly allowed to interact with MSC within the scaffolds were no longer able to recruit fibroblasts. This study illustrates the potential to use different scaffolds to regulate the dynamics of recruitment of proregenerative or fibrotic cell types through immunomodulation. Overall, this work strengths the idea that ex vivo predictive systems need to consider the different players involved in the biological response to biomaterials and that timing of arrival of specific cell types will affect the outcome. Copyright © 2017 John Wiley & Sons, Ltd.

β-Arrestin-2-Dependent Signaling Promotes CCR4-mediated Chemotaxis of Murine T-Helper Type 2 Cells.

PubMed

Lin, Rui; Choi, Yeon Ho; Zidar, David A; Walker, Julia K L

2018-06-01

Allergic asthma is a complex inflammatory disease that leads to significant healthcare costs and reduction in quality of life. Although many cell types are implicated in the pathogenesis of asthma, CD4 + T-helper cell type 2 (Th2) cells are centrally involved. We previously reported that the asthma phenotype is virtually absent in ovalbumin-sensitized and -challenged mice that lack global expression of β-arrestin (β-arr)-2 and that CD4 + T cells from these mice displayed significantly reduced CCL22-mediated chemotaxis. Because CCL22-mediated activation of CCR4 plays a role in Th2 cell regulation in asthmatic inflammation, we hypothesized that CCR4-mediated migration of CD4 + Th2 cells to the lung in asthma may use β-arr-dependent signaling. To test this hypothesis, we assessed the effect of various signaling inhibitors on CCL22-induced chemotaxis using in vitro-polarized primary CD4 + Th2 cells from β-arr2-knockout and wild-type mice. Our results show, for the first time, that CCL22-induced, CCR4-mediated Th2 cell chemotaxis is dependent, in part, on a β-arr2-dependent signaling pathway. In addition, we show that this chemotactic signaling mechanism involves activation of P-p38 and Rho-associated protein kinase. These findings point to a proinflammatory role for β-arr2-dependent signaling and support β-arr2 as a novel therapeutic target in asthma.

Antimicrobial activity of bovine NK-lysin-derived peptides on Mycoplasma bovis

USDA-ARS?s Scientific Manuscript database

Antimicrobial peptides (AMPs) are a diverse group of molecules which play an important role in the innate immune response. Bovine NK-lysins, a type of AMP, have been predominantly found in the granules of cytotoxic T-lymphocytes and NK-cells. Bovine NK-lysin-derived peptides demonstrate antimicrobia...

Antimicrobial activity of bovine NK-lysin-derived peptides on Mycoplasma bovis

USDA-ARS?s Scientific Manuscript database

Antimicrobial peptides (AMPs) are a diverse group of molecules which play an important role in the innate immune response in various organisms, including cattle. Bovine NK-lysins, a type of AMP, have been predominantly found in the granules of cytotoxic T-lymphocytes and NK-cells. Collective results...

Hepatic stellate cells in liver development, regeneration, and cancer

PubMed Central

Yin, Chunyue; Evason, Kimberley J.; Asahina, Kinji; Stainier, Didier Y.R.

2013-01-01

Hepatic stellate cells are liver-specific mesenchymal cells that play vital roles in liver physiology and fibrogenesis. They are located in the space of Disse and maintain close interactions with sinusoidal endothelial cells and hepatic epithelial cells. It is becoming increasingly clear that hepatic stellate cells have a profound impact on the differentiation, proliferation, and morphogenesis of other hepatic cell types during liver development and regeneration. In this Review, we summarize and evaluate the recent advances in our understanding of the formation and characteristics of hepatic stellate cells, as well as their function in liver development, regeneration, and cancer. We also discuss how improved knowledge of these processes offers new perspectives for the treatment of patients with liver diseases. PMID:23635788

Development of an orally-administrative MELK-targeting inhibitor that suppresses the growth of various types of human cancer.

PubMed

Chung, Suyoun; Suzuki, Hanae; Miyamoto, Takashi; Takamatsu, Naofumi; Tatsuguchi, Ayako; Ueda, Koji; Kijima, Kyoko; Nakamura, Yusuke; Matsuo, Yo

2012-12-01

We previously reported MELK (maternal embryonic leucine zipper kinase) as a novel therapeutic target for breast cancer. MELK was also reported to be highly upregulated in multiple types of human cancer. It was implied to play indispensable roles in cancer cell survival and indicated its involvement in the maintenance of tumor-initiating cells. We conducted a high-throughput screening of a compound library followed by structure-activity relationship studies, and successfully obtained a highly potent MELK inhibitor OTSSP167 with IC₅₀ of 0.41 nM. OTSSP167 inhibited the phosphorylation of PSMA1 (proteasome subunit alpha type 1) and DBNL (drebrin-like), which we identified as novel MELK substrates and are important for stem-cell characteristics and invasiveness. The compound suppressed mammosphere formation of breast cancer cells and exhibited significant tumor growth suppression in xenograft studies using breast, lung, prostate, and pancreas cancer cell lines in mice by both intravenous and oral administration. This MELK inhibitor should be a promising compound possibly to suppress the growth of tumor-initiating cells and be applied for treatment of a wide range of human cancer.

Ion Transport by Pulmonary Epithelia

PubMed Central

Hollenhorst, Monika I.; Richter, Katrin; Fronius, Martin

2011-01-01

The lung surface of air-breathing vertebrates is formed by a continuous epithelium that is covered by a fluid layer. In the airways, this epithelium is largely pseudostratified consisting of diverse cell types such as ciliated cells, goblet cells, and undifferentiated basal cells, whereas the alveolar epithelium consists of alveolar type I and alveolar type II cells. Regulation and maintenance of the volume and viscosity of the fluid layer covering the epithelium is one of the most important functions of the epithelial barrier that forms the outer surface area of the lungs. Therefore, the epithelial cells are equipped with a wide variety of ion transport proteins, among which Na+, Cl−, and K+ channels have been identified to play a role in the regulation of the fluid layer. Malfunctions of pulmonary epithelial ion transport processes and, thus, impairment of the liquid balance in our lungs is associated with severe diseases, such as cystic fibrosis and pulmonary oedema. Due to the important role of pulmonary epithelial ion transport processes for proper lung function, the present paper summarizes the recent findings about composition, function, and ion transport properties of the airway epithelium as well as of the alveolar epithelium. PMID:22131798

Review of microfluidic cell culture devices for the control of gaseous microenvironments in vitro

NASA Astrophysics Data System (ADS)

Wu, H.-M.; Lee, T.-A.; Ko, P.-L.; Chiang, H.-J.; Peng, C.-C.; Tung, Y.-C.

2018-04-01

Gaseous microenvironments play important roles in various biological activities in vivo. However, it is challenging to precisely control gaseous microenvironments in vitro for cell culture due to the high diffusivity nature of gases. In recent years, microfluidics has paved the way for the development of new types of cell culture devices capable of manipulating cellular microenvironments, and provides a powerful tool for in vitro cell studies. This paper reviews recent developments of microfluidic cell culture devices for the control of gaseous microenvironments, and discusses the advantages and limitations of current devices. We conclude with suggestions for the future development of microfluidic cell culture devices for the control of gaseous microenvironments.

[The role of endothelial cells and endothelial precursor cells in angiogenesis].

PubMed

Poreba, Małgorzata; Usnarska-Zubkiewicz, Lidia; Kuliczkowski, Kazimierz

2006-01-01

Endothelium plays a key role in maintenance of vascular homeostasis in human organism. According to new data endothelial cells and hematopoietic cells have a common precursor in prenatal life--a hemangioblast, which explains the fact of sharing the same determinants on the surface of both type of cells. Circulating endothelial precursors were identified in adults and this suggests that hemangioblasts may be present not only during embriogenesis. In some clinical situations the increased numbers of endothelial cells and endothelial precursors were noted, and especially in patients with neoplastic diseases, which is probably the result of increased angiogenesis. Endothelial precursors are thought to be the promice for therapeutic purposes in future--to increase local angiogenesis.

Kupffer Cell Metabolism and Function

PubMed Central

Nguyen-Lefebvre, Anh Thu; Horuzsko, Anatolij

2015-01-01

Kupffer cells are resident liver macrophages and play a critical role in maintaining liver functions. Under physiological conditions, they are the first innate immune cells and protect the liver from bacterial infections. Under pathological conditions, they are activated by different components and can differentiate into M1-like (classical) or M2-like (alternative) macrophages. The metabolism of classical or alternative activated Kupffer cells will determine their functions in liver damage. Special functions and metabolism of Kupffer cells suggest that they are an attractive target for therapy of liver inflammation and related diseases, including cancer and infectious diseases. Here we review the different types of Kupffer cells and their metabolism and functions in physiological and pathological conditions. PMID:26937490

The neurotrophic effects of different human dental mesenchymal stem cells.

PubMed

Kolar, Mallappa K; Itte, Vinay N; Kingham, Paul J; Novikov, Lev N; Wiberg, Mikael; Kelk, Peyman

2017-10-03

The current gold standard treatment for peripheral nerve injury is nerve grafting but this has disadvantages such as donor site morbidity. New techniques focus on replacing these grafts with nerve conduits enhanced with growth factors and/or various cell types such as mesenchymal stem cells (MSCs). Dental-MSCs (D-MSCs) including stem cells obtained from apical papilla (SCAP), dental pulp stem cells (DPSC), and periodontal ligament stem cells (PDLSC) are potential sources of MSCs for nerve repair. Here we present the characterization of various D-MSCs from the same human donors for peripheral nerve regeneration. SCAP, DPSC and PDLSC expressed BDNF, GDNF, NGF, NTF3, ANGPT1 and VEGFA growth factor transcripts. Conditioned media from D-MSCs enhanced neurite outgrowth in an in vitro assay. Application of neutralizing antibodies showed that brain derived neurotrophic factor plays an important mechanistic role by which the D-MSCs stimulate neurite outgrowth. SCAP, DPSC and PDLSC were used to treat a 10 mm nerve gap defect in a rat sciatic nerve injury model. All the stem cell types significantly enhanced axon regeneration after two weeks and showed neuroprotective effects on the dorsal root ganglia neurons. Overall the results suggested SCAP to be the optimal dental stem cell type for peripheral nerve repair.

Silencing hyperoxia-induced C/EBPα in neonatal mice improves lung architecture via enhanced proliferation of alveolar epithelial cells

PubMed Central

Yang, Guang; Hinson, Maurice D.; Bordner, Jessica E.; Lin, Qing S.; Fernando, Amal P.; La, Ping; Wright, Clyde J.

2011-01-01

Postnatal lung development requires proliferation and differentiation of specific cell types at precise times to promote proper alveolar formation. Hyperoxic exposure can disrupt alveolarization by inhibiting cell growth; however, it is not fully understood how this is mediated. The transcription factor CCAAT/enhancer binding protein-α (C/EBPα) is highly expressed in the lung and plays a role in cell proliferation and differentiation in many tissues. After 72 h of hyperoxia, C/EBPα expression was significantly enhanced in the lungs of newborn mice. The increased C/EBPα protein was predominantly located in alveolar type II cells. Silencing of C/EBPα with a transpulmonary injection of C/EBPα small interfering RNA (siRNA) prior to hyperoxic exposure reduced expression of markers of type I cell and differentiation typically observed after hyperoxia but did not rescue the altered lung morphology at 72 h. Nevertheless, when C/EBPα hyperoxia-exposed siRNA-injected mice were allowed to recover for 2 wk in room air, lung epithelial cell proliferation was increased and lung morphology was restored compared with hyperoxia-exposed control siRNA-injected mice. These data suggest that C/EBPα is an important regulator of postnatal alveolar epithelial cell proliferation and differentiation during injury and repair. PMID:21571903

Human CD8 T lymphocytes recognize Mycobacterium tuberculosis antigens presented by HLA-E during active tuberculosis and express type 2 cytokines.

PubMed

Caccamo, Nadia; Pietra, Gabriella; Sullivan, Lucy C; Brooks, Andrew G; Prezzemolo, Teresa; La Manna, Marco P; Di Liberto, Diana; Joosten, Simone A; van Meijgaarden, Krista E; Di Carlo, Paola; Titone, Lucina; Moretta, Lorenzo; Mingari, Maria C; Ottenhoff, Tom H M; Dieli, Francesco

2015-04-01

CD8 T cells contribute to protective immunity against Mycobacterium tuberculosis. In humans, M. tuberculosis reactive CD8 T cells typically recognize peptides associated to classical MHC class Ia molecules, but little information is available on CD8 T cells recognizing M. tuberculosis Ags presented by nonclassical MHC class Ib molecules. We show here that CD8 T cells from tuberculosis (TB) patients recognize HLA-E-binding M. tuberculosis peptides in a CD3/TCR αβ mediated and CD8-dependent manner, and represent an additional type of effector cells playing a role in immune response to M. tuberculosis during active infection. HLA-E-restricted recognition of M. tuberculosis peptides is detectable by a significant enhanced ex vivo frequency of tetramer-specific circulating CD8 T cells during active TB. These CD8 T cells produce type 2 cytokines upon antigenic in vitro stimulation, help B cells for Ab production, and mediate limited TRAIL-dependent cytolytic and microbicidal activity toward M. tuberculosis infected target cells. Our results, together with the finding that HLA-E/M. tuberculosis peptide specific CD8 T cells are detected in TB patients with or without HIV coinfection, suggest that this is a new human T-cell population that participates in immune response in TB. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Second Generation TQ-Ligation for Cell Organelle Imaging.

PubMed

Zhang, Xiaoyun; Dong, Ting; Li, Qiang; Liu, Xiaohui; Li, Lin; Chen, She; Lei, Xiaoguang

2015-07-17

Bioorthogonal ligations play a crucial role in labeling diverse types of biomolecules in living systems. Herein, we describe a novel class of ortho-quinolinone quinone methide (oQQM) precursors that show a faster kinetic rate in the "click cycloaddition" with thio-vinyl ether (TV) than the first generation TQ-ligation in both chemical and biological settings. We further demonstrate that the second generation TQ-ligation is also orthogonal to the widely used strain-promoted azide-alkyne cycloaddition (SPAAC) both in vitro and in vivo, revealing that these two types of bioorthogonal ligations could be used as an ideal reaction pair for the simultaneous tracking of multiple elements within a single system. Remarkably, the second generation TQ-ligation and SPAAC are effective for selective and simultaneous imaging of two different cell organelles in live cells.

Detection of Human Papillomavirus Type 2 Related Sequence in Oral Papilloma

PubMed Central

Yamaguchi, Taihei; Shindoh, Masanobu; Amemiya, Akira; Inoue, Nobuo; Kawamura, Masaaki; Sakaoka, Hiroshi; Inoue, Masakazu; Fujinaga, Kei

1998-01-01

Oral papilloma is a benign tumourous lesion. Part of this lesion is associated with human papillomavirus (HPV) infection. We analysed the genetical and histopathological evidence for HPV type 2 infection in three oral papillomas. Southern blot hybridization showed HPV 2a sequence in one lesion. Cells of the positive specimen appeared to contain high copy numbers of the viral DNA in an episomal state. In situ staining demonstrated virus capsid antigen in koilocytotic cells and surrounding cells in the hyperplastic epithelial layer. Two other specimens contained no HPV sequences by labeled probe of full length linear HPVs 2a, 6b, 11, 16, 18, 31 and 33 DNA under low stringency hybridization conditions. These results showed the possibility that HPV 2 plays a role in oral papilloma. PMID:9699941

The Roles and Regulation of Polycomb Complexes in Neural Development

PubMed Central

Corley, Matthew; Kroll, Kristen L.

2014-01-01

In the developing mammalian nervous system, common progenitors integrate both cell extrinsic and intrinsic regulatory programs to produce distinct neuronal and glial cell types as development proceeds. This spatiotemporal restriction of neural progenitor differentiation is enforced, in part, by the dynamic reorganization of chromatin into repressive domains by Polycomb Repressive Complexes, effectively limiting the expression of fate-determining genes. Here, we review distinct roles that the Polycomb Repressive Complexes play during neurogenesis and gliogenesis, while also highlighting recent work describing the molecular mechanisms that govern their dynamic activity in neural development. Further investigation of how Polycomb complexes are regulated in neural development will enable more precise manipulation of neural progenitor differentiation, facilitating the efficient generation of specific neuronal and glial cell types for many biological applications. PMID:25367430

Immunohistochemical detection of p53 protein in ameloblastoma types.

PubMed

el-Sissy, N A

1999-05-01

Overexpression of p53 protein in unicystic ameloblastoma (uAB) is denser than in the conventional ameloblastoma (cAB) type, indicating increased wild type p53--suppressing the growth potential of uAB and denoting the early event of neoplastic transformation, probably of a previous odontogenic cyst. Overexpression of p53 in borderline cAB and malignant ameloblastoma (mAB) types might reflect a mutational p53 protein playing an oncogenic role, promoting tumour growth. Overexpression of p53 protein could be a valid screening method for predicting underlying malignant genetic changes in AB types, through increased frequency of immunoreactive cells or increased staining density.

The nitric oxide-sensitive p21Ras-ERK pathway mediates S-nitrosoglutathione-induced apoptosis.

PubMed

Tsujita, Maristela; Batista, Wagner L; Ogata, Fernando T; Stern, Arnold; Monteiro, Hugo P; Arai, Roberto J

2008-05-16

p21Ras protein plays a critical role in cellular signaling that induces either cell cycle progression or apoptosis. Nitric oxide (NO) has been consistently reported to activate p21Ras through the redox sensitive cysteine residue (118). In this study, we demonstrated that the p21Ras-ERK pathway regulates THP-1 monocyte/macrophage apoptosis induced by S-nitrosoglutathione (SNOG). This was apparent from studies in THP-1 cells expressing NO-insensitive p21Ras (p21Ras(C118S)) where the pro-apoptotic action of SNOG was almost abrogated. Three major MAP kinase pathways (ERK, JNK, and p38) that are downstream to p21Ras were investigated. It was observed that only the activation of ERK1/2 MAP kinases by SNOG in THP-1 cells was attributable to p21Ras. The inhibition of the ERK pathway by PD98059 markedly attenuated apoptosis in SNOG-treated THP-1 cells, but had a marginal effect on SNOG-treated THP-1 cells expressing NO-insensitive p21Ras. The inhibition of the JNK and p38 pathways by selective inhibitors had no marked effects on the percentage of apoptosis. The induction of p21Waf1 expression by SNOG was observed in THP-1 cells harboring mutant and wild-type p21Ras, however in cells expressing mutant Ras, the expression of p21Waf1 was significantly attenuated. The treatment of THP-1 cells expressing wild-type p21Ras with PD98059 resulted in significant attenuation of p21Waf1 expression. These results indicate that the redox sensitive p21Ras-ERK pathway plays a critical role in sensing and delivering the pro-apoptotic signaling mediated by SNOG.

The nitric oxide-sensitive p21Ras-ERK pathway mediates S-nitrosoglutathione-induced apoptosis

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

Tsujita, Maristela; Faculdade de Ciencias Farmaceuticas, Universidade de Sao Paulo, SP; Batista, Wagner L.

2008-05-16

p21Ras protein plays a critical role in cellular signaling that induces either cell cycle progression or apoptosis. Nitric oxide (NO) has been consistently reported to activate p21Ras through the redox sensitive cysteine residue (118). In this study, we demonstrated that the p21Ras-ERK pathway regulates THP-1 monocyte/macrophage apoptosis induced by S-nitrosoglutathione (SNOG). This was apparent from studies in THP-1 cells expressing NO-insensitive p21Ras (p21Ras{sup C118S}) where the pro-apoptotic action of SNOG was almost abrogated. Three major MAP kinase pathways (ERK, JNK, and p38) that are downstream to p21Ras were investigated. It was observed that only the activation of ERK1/2 MAP kinasesmore » by SNOG in THP-1 cells was attributable to p21Ras. The inhibition of the ERK pathway by PD98059 markedly attenuated apoptosis in SNOG-treated THP-1 cells, but had a marginal effect on SNOG-treated THP-1 cells expressing NO-insensitive p21Ras. The inhibition of the JNK and p38 pathways by selective inhibitors had no marked effects on the percentage of apoptosis. The induction of p21Waf1 expression by SNOG was observed in THP-1 cells harboring mutant and wild-type p21Ras, however in cells expressing mutant Ras, the expression of p21Waf1 was significantly attenuated. The treatment of THP-1 cells expressing wild-type p21Ras with PD98059 resulted in significant attenuation of p21Waf1 expression. These results indicate that the redox sensitive p21Ras-ERK pathway plays a critical role in sensing and delivering the pro-apoptotic signaling mediated by SNOG.« less

Myosins XI-K, XI-1, and XI-2 are required for development of pavement cells, trichomes, and stigmatic papillae in Arabidopsis

PubMed Central

2012-01-01

Background The positioning and dynamics of vesicles and organelles, and thus the growth of plant cells, is mediated by the acto-myosin system. In Arabidopsis there are 13 class XI myosins which mediate vesicle and organelle transport in different cell types. So far the involvement of five class XI myosins in cell expansion during the shoot and root development has been shown, three of which, XI-1, XI-2, and XI-K, are essential for organelle transport. Results Simultaneous depletion of Arabidopsis class XI myosins XI-K, XI-1, and XI-2 in double and triple mutant plants affected the growth of several types of epidermal cells. The size and shape of trichomes, leaf pavement cells and the elongation of the stigmatic papillae of double and triple mutant plants were affected to different extent. Reduced cell size led to significant size reduction of shoot organs in the case of triple mutant, affecting bolt formation, flowering time and fertility. Phenotype analysis revealed that the reduced fertility of triple mutant plants was caused by delayed or insufficient development of pistils. Conclusions We conclude that the class XI myosins XI-K, XI-1 and XI-2 have partially redundant roles in the growth of shoot epidermis. Myosin XI-K plays more important role whereas myosins XI-1 and XI-2 have minor roles in the determination of size and shape of epidermal cells, because the absence of these two myosins is compensated by XI-K. Co-operation between myosins XI-K and XI-2 appears to play an important role in these processes. PMID:22672737

Emerging concepts and future challenges in innate lymphoid cell biology

PubMed Central

Artis, David

2016-01-01

Innate lymphoid cells (ILCs) are innate immune cells that are ubiquitously distributed in lymphoid and nonlymphoid tissues and enriched at mucosal and barrier surfaces. Three major ILC subsets are recognized in mice and humans. Each of these subsets interacts with innate and adaptive immune cells and integrates cues from the epithelium, the microbiota, and pathogens to regulate inflammation, immunity, tissue repair, and metabolic homeostasis. Although intense study has elucidated many aspects of ILC development, phenotype, and function, numerous challenges remain in the field of ILC biology. In particular, recent work has highlighted key new questions regarding how these cells communicate with their environment and other cell types during health and disease. This review summarizes new findings in this rapidly developing field that showcase the critical role ILCs play in directing immune responses through their ability to interact with a variety of hematopoietic and nonhematopoietic cells. In addition, we define remaining challenges and emerging questions facing the field. Finally, this review discusses the potential application of basic studies of ILC biology to the development of new treatments for human patients with inflammatory and infectious diseases in which ILCs play a role. PMID:27811053

The differential expression of IL-4 and IL-13 and its impact on type-2 immunity.

PubMed

Bao, Katherine; Reinhardt, R Lee

2015-09-01

Allergic disease represents a significant global health burden, and disease incidence continues to rise in urban areas of the world. As such, a better understanding of the basic immune mechanisms underlying disease pathology are key to developing therapeutic interventions to both prevent disease onset as well as to ameliorate disease morbidity in those individuals already suffering from a disorder linked to type-2 inflammation. Two factors central to type-2 immunity are interleukin (IL)-4 and IL-13, which have been linked to virtually all major hallmarks associated with type-2 inflammation. Therefore, IL-4 and IL-13 and their regulatory pathways represent ideal targets to suppress disease. Despite sharing many common regulatory pathways and receptors, these cytokines perform very distinct functions during a type-2 immune response. This review summarizes the literature surrounding the function and expression of IL-4 and IL-13 in CD4+ T cells and innate immune cells. It highlights recent findings in vivo regarding the differential expression and non-canonical regulation of IL-4 and IL-13 in various immune cells, which likely play important and underappreciated roles in type-2 immunity. Copyright © 2015 Elsevier Ltd. All rights reserved.

Transitions from mono- to co- to tri-culture uniquely affect gene expression in breast cancer, stromal, and immune compartments.

PubMed

Regier, Mary C; Maccoux, Lindsey J; Weinberger, Emma M; Regehr, Keil J; Berry, Scott M; Beebe, David J; Alarid, Elaine T

2016-08-01

Heterotypic interactions in cancer microenvironments play important roles in disease initiation, progression, and spread. Co-culture is the predominant approach used in dissecting paracrine interactions between tumor and stromal cells, but functional results from simple co-cultures frequently fail to correlate to in vivo conditions. Though complex heterotypic in vitro models have improved functional relevance, there is little systematic knowledge of how multi-culture parameters influence this recapitulation. We therefore have employed a more iterative approach to investigate the influence of increasing model complexity; increased heterotypic complexity specifically. Here we describe how the compartmentalized and microscale elements of our multi-culture device allowed us to obtain gene expression data from one cell type at a time in a heterotypic culture where cells communicated through paracrine interactions. With our device we generated a large dataset comprised of cell type specific gene-expression patterns for cultures of increasing complexity (three cell types in mono-, co-, or tri-culture) not readily accessible in other systems. Principal component analysis indicated that gene expression was changed in co-culture but was often more strongly altered in tri-culture as compared to mono-culture. Our analysis revealed that cell type identity and the complexity around it (mono-, co-, or tri-culture) influence gene regulation. We also observed evidence of complementary regulation between cell types in the same heterotypic culture. Here we demonstrate the utility of our platform in providing insight into how tumor and stromal cells respond to microenvironments of varying complexities highlighting the expanding importance of heterotypic cultures that go beyond conventional co-culture.

Fair Play: A Study of Scientific Workforce Trainers' Experience Playing an Educational Video Game about Racial Bias.

PubMed

Kaatz, Anna; Carnes, Molly; Gutierrez, Belinda; Savoy, Julia; Samuel, Clem; Filut, Amarette; Pribbenow, Christine Maidl

2017-01-01

Explicit racial bias has decreased in the United States, but racial stereotypes still exist and conspire in multiple ways to perpetuate the underparticipation of Blacks in science careers. Capitalizing on the potential effectiveness of role-playing video games to promote the type of active learning required to increase awareness of and reduce subtle racial bias, we developed the video game Fair Play, in which players take on the role of Jamal, a Black male graduate student in science, who experiences discrimination in his PhD program. We describe a mixed-methods evaluation of the experience of scientific workforce trainers who played Fair Play at the National Institutes of Health Division of Training Workforce Development and Diversity program directors' meeting in 2013 ( n = 47; 76% female, n = 34; 53% nonwhite, n = 26). The evaluation findings suggest that Fair Play can promote perspective taking and increase bias literacy, which are steps toward reducing racial bias and affording Blacks equal opportunities to excel in science. © 2017 A. Kaatz et al. CBE—Life Sciences Education © 2017 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Development of Efficient and Stable Inverted Bulk Heterojunction (BHJ) Solar Cells Using Different Metal Oxide Interfaces

PubMed Central

Litzov, Ivan; Brabec, Christoph J.

2013-01-01

Solution-processed inverted bulk heterojunction (BHJ) solar cells have gained much more attention during the last decade, because of their significantly better environmental stability compared to the normal architecture BHJ solar cells. Transparent metal oxides (MeOx) play an important role as the dominant class for solution-processed interface materials in this development, due to their excellent optical transparency, their relatively high electrical conductivity and their tunable work function. This article reviews the advantages and disadvantages of the most common synthesis methods used for the wet chemical preparation of the most relevant n-type- and p-type-like MeOx interface materials consisting of binary compounds AxBy. Their performance for applications as electron transport/extraction layers (ETL/EEL) and as hole transport/extraction layers (HTL/HEL) in inverted BHJ solar cells will be reviewed and discussed. PMID:28788423

Characterization of soluble glycoprotein D-mediated herpes simplex virus type 1 infection

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

Tsvitov, Marianna; Frampton, Arthur R.; Shah, Waris A.

2007-04-10

Herpes simplex virus type 1 (HSV-1) entry into permissive cells involves attachment to cell-surface glycosaminoglycans (GAGs) and fusion of the virus envelope with the cell membrane triggered by the binding of glycoprotein D (gD) to cognate receptors. In this study, we characterized the observation that soluble forms of the gD ectodomain (sgD) can mediate entry of gD-deficient HSV-1. We examined the efficiency and receptor specificity of this activity and used sequential incubation protocols to determine the order and stability of the initial interactions required for entry. Surprisingly, virus binding to GAGs did not increase the efficiency of sgD-mediated entry andmore » gD-deficient virus was capable of attaching to GAG-deficient cells in the absence of sgD. These observations suggested a novel binding interaction that may play a role in normal HSV infection.« less

Development of Efficient and Stable Inverted Bulk Heterojunction (BHJ) Solar Cells Using Different Metal Oxide Interfaces.

PubMed

Litzov, Ivan; Brabec, Christoph J

2013-12-10

Solution-processed inverted bulk heterojunction (BHJ) solar cells have gained much more attention during the last decade, because of their significantly better environmental stability compared to the normal architecture BHJ solar cells. Transparent metal oxides (MeO x ) play an important role as the dominant class for solution-processed interface materials in this development, due to their excellent optical transparency, their relatively high electrical conductivity and their tunable work function. This article reviews the advantages and disadvantages of the most common synthesis methods used for the wet chemical preparation of the most relevant n -type- and p -type-like MeO x interface materials consisting of binary compounds A x B y . Their performance for applications as electron transport/extraction layers (ETL/EEL) and as hole transport/extraction layers (HTL/HEL) in inverted BHJ solar cells will be reviewed and discussed.

Effects of resource supplements on mature ciliate biofilms: an empirical test using a new type of flow cell.

PubMed

Norf, Helge; Arndt, Hartmut; Weitere, Markus

2009-11-01

Biofilm-dwelling consumer communities play an important role in the matter flux of many aquatic ecosystems. Due to their poor accessibility, little is as yet known about the regulation of natural biofilms. Here, a new type of flow cell is presented which facilitates both experimental manipulation and live observation of natural, pre-grown biofilms. These flow cells were used to study the dynamics of mature ciliate biofilms in response to supplementation of planktonic bacteria. The results suggest that enhanced ciliate productivity could be quickly transferred to micrometazoans (ciliate grazers), making the effects on the standing stock of the ciliates detectable only for a short time. Likewise, no effect on ciliates appeared when micrometazoan consumers were ab initio abundant. This indicates the importance of 'top-down' control of natural ciliate biofilms. The flow cells used here offer great potential for experimentally testing such control mechanisms within naturally cultivated biofilms.

Effect of Cell Aspect Ratio on Swarming Bacteria

NASA Astrophysics Data System (ADS)

Ilkanaiv, Bella; Kearns, Daniel B.; Ariel, Gil; Be'er, Avraham

2017-04-01

Swarming bacteria collectively migrate on surfaces using flagella, forming dynamic whirls and jets that consist of millions of individuals. Because some swarming bacteria elongate prior to actual motion, cell aspect ratio may play a significant role in the collective dynamics. Extensive research on self-propelled rodlike particles confirms that elongation promotes alignment, strongly affecting the dynamics. Here, we study experimentally the collective dynamics of variants of swarming Bacillus subtilis that differ in length. We show that the swarming statistics depends on the aspect ratio in a critical, fundamental fashion not predicted by theory. The fastest motion was obtained for the wild-type and variants that are similar in length. However, shorter and longer cells exhibit anomalous, non-Gaussian statistics and nonexponential decay of the autocorrelation function, indicating lower collective motility. These results suggest that the robust mechanisms to maintain aspect ratios may be important for efficient swarming motility. Wild-type cells are optimal in this sense.

Cytological diagnosis of tuberculous cervicitis: A case report with review of literature.

PubMed

Kalyani, R; Sheela, Sr; Rajini, M

2012-01-01

Tuberculosis of cervix is a rare disease. Tuberculosis usually affects women of childbearing age, indicating hormone dependence of infection. The patient presents with menstrual irregularities, infertility or vaginal discharge. Cervical lesions presents as papillary/vegetative growth or ulceration mimicking cervical cancer. Cervical Papanicolaou (Pap) smear plays an important role in diagnosing the disease by non-invasive technique in which the presence of epithelioid cells and Langhan's type of giant cells is diagnostic. However, other causes of granulomatous cervicitis should be considered and ruled out. Ziehl-Neelsen (ZN) stain for acid fast bacilli, fluorescent technique, biopsy and culture help in confirming the disease. We present the case of a 45-year-old female, who presented with vaginal discharge, dysfunctional uterine bleeding, first degree uterine descent with grade II cystocele and rectocele and cervical ulcer. Pap smear revealed epithelioid cells and Langhan's type of giant cells, confirmed by ZN stain of cervical smear, fluorescent technique and culture.

Cellular and Molecular Players in Adipose Tissue Inflammation in the Development of Obesity-induced Insulin Resistance

PubMed Central

Lee, Byung-Cheol; Lee, Jongsoon

2013-01-01

There is increasing evidence showing that inflammation is an important pathogenic mediator of the development of obesity-induced insulin resistance. It is now generally accepted that tissue-resident immune cells play a major role in the regulation of this obesity-induced inflammation. The roles that adipose tissue (AT)-resident immune cells play have been particularly extensively studied. AT contains most types of immune cells and obesity increases their numbers and activation levels, particularly in AT macrophages (ATMs). Other pro-inflammatory cells found in AT include neutrophils, Th1 CD4 T cells, CD8 T cells, B cells, DCs, and mast cells. However, AT also contains anti-inflammatory cells that counter the pro-inflammatory immune cells that are responsible for the obesity-induced inflammation in this tissue. These anti-inflammatory cells include regulatory CD4 T cells (Tregs), Th2 CD4 T cells, and eosinophils. Hence, AT inflammation is shaped by the regulation of pro- and anti-inflammatory immune cell homeostasis, and obesity skews this balance towards a more pro-inflammatory status. Recent genetic studies revealed several molecules that participate in the development of obesity-induced inflammation and insulin resistance. In this review, the cellular and molecular players that participate in the regulation of obesity-induced inflammation and insulin resistance are discussed, with particular attention being placed on the roles of the cellular players in these pathogeneses. PMID:23707515

[Extracellular matrix--regulation of cancer invasion and metastasis].

PubMed

Watanabe, Hideto

2010-11-01

Cancer cell invasion comprises steps in the destruction of the basement membrane and migration of cells into the connective tissue. These cells further migrate into lymph ducts and small vessels to reach metastasis. The extracellular matrix (ECM) provides a microenvironment for cells, and its destruction is associated with cancer cell invasion. Among matrix metalloproteinases (MMPs), both MMP-2 and 9 digest type IV collagen, a major component of the basement membrane, and MMP-14/MT1-MMP, a membrane-type MMP, activates MMP-2. Thus, these MMPs play a central role in cancer cell invasion. MMPs also cleave latent forms of growth factors and signaling molecules, releasing and activating them, which influence neo-vascularization and cancer apoptosis. Like proteins, carbohydrates are known to be involved in cancer invasion. Hyaluronan is known to both stimulate and inhibit cancer invasion, depending on its molecular size. Heparanase, which digests heparan sulfate, is known to facilitate cancer invasion and metastasis. In summary, ECM provides a microenvironment that regulates cell behavior and its structure altered by MMPs affects cancer cell invasion.

Mutation in the peb1A Locus of Campylobacter jejuni Reduces Interactions with Epithelial Cells and Intestinal Colonization of Mice

PubMed Central

Pei, Zhiheng; Burucoa, Christophe; Grignon, Bernadette; Baqar, Shahida; Huang, Xiao-Zhe; Kopecko, Dennis J.; Bourgeois, A. L.; Fauchere, Jean-Louis; Blaser, Martin J.

1998-01-01

Campylobacter jejuni is one of the leading causes of bacterial diarrhea throughout the world. We previously found that PEB1 is a homolog of cluster 3 binding proteins of bacterial ABC transporters and that a C. jejuni adhesin, cell-binding factor 1 (CBF1), if not identical to, contains PEB1. A single protein migrating at approximately 27 to 28 kDa was recognized by anti-CBF1 and anti-PEB1. To determine the role that the operon encoding PEB1 plays in C. jejuni adherence, peb1A, the gene encoding PEB1, was disrupted in strain 81-176 by insertion of a kanamycin resistance gene through homologous recombination. Inactivation of this operon completely abolished expression of CBF1, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting. In comparison to the wild-type strain, the mutant strain showed 50- to 100-fold less adherence to and 15-fold less invasion of epithelial cells in culture. Mouse challenge studies showed that the rate and duration of intestinal colonization by the mutant were significantly lower and shorter than with the wild-type strain. In summary, PEB1 is identical to a previously identified cell-binding factor, CBF1, in C. jejuni, and the peb1A locus plays an important role in epithelial cell interactions and in intestinal colonization in a mouse model. PMID:9488379

Receptor-like kinases as surface regulators for RAC/ROP-mediated pollen tube growth and interaction with the pistil

PubMed Central

Zou, Yanjiao; Aggarwal, Mini; Zheng, Wen-Guang; Wu, Hen-Ming; Cheung, Alice Y.

2011-01-01

Background RAC/ROPs are RHO-type GTPases and are known to play diverse signalling roles in plants. Cytoplasmic RAC/ROPs are recruited to the cell membrane and activated in response to extracellular signals perceived and mediated by cell surface-located signalling assemblies, transducing the signals to regulate cellular processes. More than any other cell types in plants, pollen tubes depend on continuous interactions with an extracellular environment produced by their surrounding tissues as they grow within the female organ pistil to deliver sperm to the female gametophyte for fertilization. Scope We review studies on pollen tube growth that provide compelling evidence indicating that RAC/ROPs are crucial for regulating the cellular processes that underlie the polarized cell growth process. Efforts to identify cell surface regulators that mediate extracellular signals also point to RAC/ROPs being the molecular switches targeted by growth-regulating female factors for modulation to mediate pollination and fertilization. We discuss a large volume of work spanning more than two decades on a family of pollen-specific receptor kinases and some recent studies on members of the FERONIA family of receptor-like kinases (RLKs). Significance The research described shows the crucial roles that two RLK families play in transducing signals from growth regulatory factors to the RAC/ROP switch at the pollen tube apex to mediate and target pollen tube growth to the female gametophyte and signal its disintegration to achieve fertilization once inside the female chamber. PMID:22476487

Chemokine CXCL11 links microbial stimuli to intestinal inflammation

PubMed Central

Liu, Z; Chen, X; Wang, X; Chen, X; Song, C-H; Du, Y; Su, J; Yaseen, S A; Yang, P-C

2011-01-01

Interleukin (IL)-17 plays an important role in the pathogenesis in a number of immune inflammatory disorders. This study aims to investigate the mechanism by which microbial product flagellin is involved in the development of T helper type (Th)17 cells. Serum levels of IL-17 and CXCL9-11 in patients with ulcerative colitis (UC) were evaluated. The source and mechanism of CXC11 release in intestinal mucosa were examined with colonic biopsies from UC patients and a colitis mouse model. The role of flagellin in the development of Th17 cells was studied with a cell co-culture system. High serum levels of CXCL11 and IL-17 were observed in UC. Flagellin could induce the production of CXCL11 in CD14+ cells that facilitated the development of Th17 cells. In a skewed Th1 response environment flagellin induces intestinal inflammation, with IL-17 expression predominant. CXCR3/CXCL11 pathway is involved in microbial product flagellin-induced intestinal inflammation in which the Th17 response plays an important role. PMID:21438871

Downregulation of TFPI in breast cancer cells induces tyrosine phosphorylation signaling and increases metastatic growth by stimulating cell motility

PubMed Central

2011-01-01

Background Increased hemostatic activity is common in many cancer types and often causes additional complications and even death. Circumstantial evidence suggests that tissue factor pathway inhibitor-1 (TFPI) plays a role in cancer development. We recently reported that downregulation of TFPI inhibited apoptosis in a breast cancer cell line. In this study, we investigated the effects of TFPI on self-sustained growth and motility of these cells, and of another invasive breast cancer cell type (MDA-MB-231). Methods Stable cell lines with TFPI (both α and β) and only TFPIβ downregulated were created using RNA interference technology. We investigated the ability of the transduced cells to grow, when seeded at low densities, and to form colonies, along with metastatic characteristics such as adhesion, migration and invasion. Results Downregulation of TFPI was associated with increased self-sustained cell growth. An increase in cell attachment and spreading was observed to collagen type I, together with elevated levels of integrin α2. Downregulation of TFPI also stimulated migration and invasion of cells, and elevated MMP activity was involved in the increased invasion observed. Surprisingly, equivalent results were observed when TFPIβ was downregulated, revealing a novel function of this isoform in cancer metastasis. Conclusions Our results suggest an anti-metastatic effect of TFPI and may provide a novel therapeutic approach in cancer. PMID:21849050

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

Liu, Fabao; Department of Biochemistry, College of Life Sciences, Nankai University, Tianjin 300071; You, Xiaona

Highlights: • Relative to wild type HBx, HBX mutant HBxΔ127 strongly enhances cell proliferation. • Relative to wild type HBx, HBxΔ127 remarkably up-regulates miR-215 in hepatoma cells. • HBxΔ127-elevated miR-215 promotes cell proliferation via targeting PTPRT mRNA. - Abstract: The mutant of virus is a frequent event. Hepatitis B virus X protein (HBx) plays a vital role in the development of hepatocellular carcinoma (HCC). Therefore, the identification of potent mutant of HBx in hepatocarcinogenesis is significant. Previously, we identified a natural mutant of the HBx gene (termed HBxΔ127). Relative to wild type HBx, HBxΔ127 strongly enhanced cell proliferation and migrationmore » in HCC. In this study, we aim to explore the mechanism of HBxΔ127 in promotion of proliferation of hepatoma cells. Our data showed that both wild type HBx and HBxΔ127 could increase the expression of miR-215 in hepatoma HepG2 and H7402 cells. However, HBxΔ127 was able to significantly increase miR-215 expression relative to wild type HBx in the cells. We identified that protein tyrosine phosphatase, receptor type T (PTPRT) was one of the target genes of miR-215 through targeting 3′UTR of PTPRT mRNA. In function, miR-215 was able to promote the proliferation of hepatoma cells. Meanwhile anti-miR-215 could partially abolish the enhancement of cell proliferation mediated by HBxΔ127 in vitro. Knockdown of PTPRT by siRNA could distinctly suppress the decrease of cell proliferation mediated by anti-miR-215 in HepG2-XΔ127/H7402-XΔ127 cells. Moreover, we found that anti-miR-215 remarkably inhibited the tumor growth of hepatoma cells in nude mice. Collectively, relative to wild type HBx, HBxΔ127 strongly enhances proliferation of hepatoma cells through up-regulating miR-215 targeting PTPRT. Our finding provides new insights into the mechanism of HBx mutant HBxΔ127 in promotion of proliferation of hepatoma cells.« less

Differences in Cell Division Rates Drive the Evolution of Terminal Differentiation in Microbes

PubMed Central

Matias Rodrigues, João F.; Rankin, Daniel J.; Rossetti, Valentina; Wagner, Andreas; Bagheri, Homayoun C.

2012-01-01

Multicellular differentiated organisms are composed of cells that begin by developing from a single pluripotent germ cell. In many organisms, a proportion of cells differentiate into specialized somatic cells. Whether these cells lose their pluripotency or are able to reverse their differentiated state has important consequences. Reversibly differentiated cells can potentially regenerate parts of an organism and allow reproduction through fragmentation. In many organisms, however, somatic differentiation is terminal, thereby restricting the developmental paths to reproduction. The reason why terminal differentiation is a common developmental strategy remains unexplored. To understand the conditions that affect the evolution of terminal versus reversible differentiation, we developed a computational model inspired by differentiating cyanobacteria. We simulated the evolution of a population of two cell types –nitrogen fixing or photosynthetic– that exchange resources. The traits that control differentiation rates between cell types are allowed to evolve in the model. Although the topology of cell interactions and differentiation costs play a role in the evolution of terminal and reversible differentiation, the most important factor is the difference in division rates between cell types. Faster dividing cells always evolve to become the germ line. Our results explain why most multicellular differentiated cyanobacteria have terminally differentiated cells, while some have reversibly differentiated cells. We further observed that symbioses involving two cooperating lineages can evolve under conditions where aggregate size, connectivity, and differentiation costs are high. This may explain why plants engage in symbiotic interactions with diazotrophic bacteria. PMID:22511858

Lectin-resistant variants of mouse Lewis lung carcinoma cells. II. Altered glycosylation of membrane glycoproteins.

PubMed

Debray, H; Dus, D; Hueso, P; Radzikowski, C; Montreuil, J

1990-01-01

Lectin-resistant variants of mouse Lewis lung carcinoma LL2 cell line, selected with wheat germ agglutinin (WGAR), Ricinus communis agglutinin II (RCA IIR) and Aleuria aurantia agglutinin (AAAR) were studied. Total cellular glycopeptides of the parent LL2 line and of the five lectin-resistant variants were analyzed by gel filtration and affinity chromatography on immobilized concanavalin A and Lens culinaris agglutinin. The results revealed that low-metastatic WGAR and RCA IIR variants possessed less highly branched tri- and tetra-antennary N-acetyllactosaminic type glycans with a simultaneous increase in biantennary N-acetyllactosaminic type, oligomannosidic type or hybrid type glycans, as compared to the parent metastasizing LL2 cell line. These findings imply that cell surface carbohydrate changes may possibly be relevant for metastasis. However, the AAAR variant, which possessed reduced spontaneous metastatic ability after s.c. administration, but increased experimental metastatic ability after i.v. inoculation, exhibited apparently the same glycan pattern than the parent LL2 line. This particular variant is under investigation in order to find specific modification(s) of glycan(s) which could play a specific role in the metastatic process.

Physiological pathways regulating the activity of magnocellular neurosecretory cells.

PubMed

Leng, G; Brown, C H; Russell, J A

1999-04-01

Magnocellular oxytocin and vasopressin cells are among the most extensively studied neurons in the brain; their large size and high synthetic capacity, their discrete, homogeneous distribution and the anatomical separation of their terminals from their cell bodies, and the ability to determine their neuronal output readily by measurements of hormone concentration in the plasma, combine to make these systems amenable to a wide range of fundamental investigations. While vasopressin cells have intrinsic burst-generating properties, oxytocin cells are organized within local pattern-generating networks. In this review we consider the rôle played by particular afferent pathways in the regulation of the activity of oxytocin and vasopressin cells. For both cell types, the effects of changes in the activity of synaptic input can be complex.

Rapid, high efficiency isolation of pancreatic ß-cells.

PubMed

Clardy, Susan M; Mohan, James F; Vinegoni, Claudio; Keliher, Edmund J; Iwamoto, Yoshiko; Benoist, Christophe; Mathis, Diane; Weissleder, Ralph

2015-09-02

The ability to isolate pure pancreatic ß-cells would greatly aid multiple areas of diabetes research. We developed a fluorescent exendin-4-like neopeptide conjugate for the rapid purification and isolation of functional mouse pancreatic β-cells. By targeting the glucagon-like peptide-1 receptor with the fluorescent conjugate, β-cells could be quickly isolated by flow cytometry and were >99% insulin positive. These studies were confirmed by immunostaining, microscopy and gene expression profiling on isolated cells. Gene expression profiling studies of cytofluorometrically sorted β-cells from 4 and 12 week old NOD mice provided new insights into the genetic programs at play of different stages of type-1 diabetes development. The described isolation method should have broad applicability to the β-cell field.

Unipotent, Atoh1+ progenitors maintain the Merkel cell population in embryonic and adult mice

PubMed Central

Wright, Margaret C.; Reed-Geaghan, Erin G.; Bolock, Alexa M.; Fujiyama, Tomoyuki; Hoshino, Mikio

2015-01-01

Resident progenitor cells in mammalian skin generate new cells as a part of tissue homeostasis. We sought to identify the progenitors of Merkel cells, a unique skin cell type that plays critical roles in mechanosensation. We found that some Atoh1-expressing cells in the hairy skin and whisker follicles are mitotically active at embryonic and postnatal ages. Genetic fate-mapping revealed that these Atoh1-expressing cells give rise solely to Merkel cells. Furthermore, selective ablation of Atoh1+ skin cells in adult mice led to a permanent reduction in Merkel cell numbers, demonstrating that other stem cell populations are incapable of producing Merkel cells. These data identify a novel, unipotent progenitor population in the skin that gives rise to Merkel cells both during development and adulthood. PMID:25624394

B cell modulation strategies in autoimmunity: the SLE example.

PubMed

Rosado, M Manuela; Diamanti, Andrea Picchianti; Capolunghi, Federica; Carsetti, Rita

2011-01-01

The paradigm that T cells are the prime effectors of autoimmune diseases has been recently challenged by growing evidence that B-lymphocytes play a role in the development, re-activation and persistence of autoimmune disorders. B-cells of different subsets may play different roles in autoimmune pathologies due to their ability to secrete antibodies, produce cytokines, present antigen and form ectopic germinal centers. Thus, a given therapeutic approach or drug may have distinct outcomes depending on which specific B cell subset is targeted. Immunosuppressive therapies such as azathioprine (AZA), cyclophosphamide (CyC) or methotrexate (MTX) are conventionally used in autoimmune diseases with the aim of reducing disease activity and improving the patient's general health conditions. These treatments do not target a specific cellular type or subset and have substantial side effects, such as impairment of liver function and fertility. Moreover, autoimmune patients may be refractory to immunosuppressive therapy. In these cases finding an effective treatment becomes a challenge. The fast evolution in antibody technology is leading to the production of a wide array of humanized monoclonal antibodies, targeting specific cell types or pathways, initiating a new era in the treatment of autoimmune disorders. In addition, the recent discovery that toll like receptors (TLRs) activation can fire up autoimmunity in humans and maintain disease gives the grounds for the development of new drugs targeting the TLR/MyD88 pathway. In contrast to conventional immune-suppression, the availability of drugs interfering with B-cell specific pathogenetic pathways gives the possibility to choose therapies tailored to each disease and, possibly, to each patient.

Small intestinal eosinophils regulate Th17 cells by producing IL-1 receptor antagonist.

PubMed

Sugawara, Reiko; Lee, Eun-Jung; Jang, Min Seong; Jeun, Eun-Ji; Hong, Chun-Pyo; Kim, Jung-Hwan; Park, Areum; Yun, Chang Ho; Hong, Sung-Wook; Kim, You-Me; Seoh, Ju-Young; Jung, YunJae; Surh, Charles D; Miyasaka, Masayuki; Yang, Bo-Gie; Jang, Myoung Ho

2016-04-04

Eosinophils play proinflammatory roles in helminth infections and allergic diseases. Under steady-state conditions, eosinophils are abundantly found in the small intestinal lamina propria, but their physiological function is largely unexplored. In this study, we found that small intestinal eosinophils down-regulate Th17 cells. Th17 cells in the small intestine were markedly increased in the ΔdblGATA-1 mice lacking eosinophils, and an inverse correlation was observed between the number of eosinophils and that of Th17 cells in the small intestine of wild-type mice. In addition, small intestinal eosinophils suppressed the in vitro differentiation of Th17 cells, as well as IL-17 production by small intestinal CD4(+)T cells. Unlike other small intestinal immune cells or circulating eosinophils, we found that small intestinal eosinophils have a unique ability to constitutively secrete high levels of IL-1 receptor antagonist (IL-1Ra), a natural inhibitor of IL-1β. Moreover, small intestinal eosinophils isolated from IL-1Ra-deficient mice failed to suppress Th17 cells. Collectively, our results demonstrate that small intestinal eosinophils play a pivotal role in the maintenance of intestinal homeostasis by regulating Th17 cells via production of IL-1Ra. © 2016 Sugawara et al.

Small intestinal eosinophils regulate Th17 cells by producing IL-1 receptor antagonist

PubMed Central

Sugawara, Reiko; Lee, Eun-Jung; Jang, Min Seong; Jeun, Eun-Ji; Hong, Chun-Pyo; Kim, Jung-Hwan; Park, Areum; Yun, Chang Ho; Hong, Sung-Wook; Kim, You-Me; Seoh, Ju-Young; Jung, YunJae; Surh, Charles D.; Miyasaka, Masayuki

2016-01-01

Eosinophils play proinflammatory roles in helminth infections and allergic diseases. Under steady-state conditions, eosinophils are abundantly found in the small intestinal lamina propria, but their physiological function is largely unexplored. In this study, we found that small intestinal eosinophils down-regulate Th17 cells. Th17 cells in the small intestine were markedly increased in the ΔdblGATA-1 mice lacking eosinophils, and an inverse correlation was observed between the number of eosinophils and that of Th17 cells in the small intestine of wild-type mice. In addition, small intestinal eosinophils suppressed the in vitro differentiation of Th17 cells, as well as IL-17 production by small intestinal CD4+ T cells. Unlike other small intestinal immune cells or circulating eosinophils, we found that small intestinal eosinophils have a unique ability to constitutively secrete high levels of IL-1 receptor antagonist (IL-1Ra), a natural inhibitor of IL-1β. Moreover, small intestinal eosinophils isolated from IL-1Ra−deficient mice failed to suppress Th17 cells. Collectively, our results demonstrate that small intestinal eosinophils play a pivotal role in the maintenance of intestinal homeostasis by regulating Th17 cells via production of IL-1Ra. PMID:26951334

The effects of focal adhesion kinase on the motility, proliferation and apoptosis of Caco2 and SMMC-7721 cells.

PubMed

Gao, Ning; He, Huimin; Xiao, Li; Gao, Xiaojie; Shi, Hongyan; Wu, Qiong; Xu, Nan; Lei, Yuqing; Song, Xigui; Hou, Yingchun

2015-04-01

Focal adhesion kinase (FAK) plays important roles in cancer development. However, the significance of FAK expression in colorectal carcinoma and hepatocellular carcinoma has not been clarified. This study aims to explore the roles FAK played in the progression of colorectal carcinoma and hepatocellular carcinoma. RNAi method was used to inhibit the expression of FAK in Caco2 and SMMC-7721 cells. Reverse transcriptase polymerase chain reaction analysis and Western blot analysis were used to examine mRNA and protein expression of FAK. Then, the proliferation, motility and apoptosis of both types of cells were detected using MTT assay, wound healing/transwell assay and nuclear staining assay. The microstructure changes (F-actin, β-tubulin and lamin B1) of SMMC-7721 cells were visualized by immunofluorescence. FAK was overexpressed in both cell lines and down-regulation of FAK resulted in suppression of cell proliferation, inhibition of cell migration and invasion. The apoptosis of cells was increased significantly following the FAK expression inhibition. Moreover, actin polymerization, β-tubulin and lamin B1 expression of cells were significantly decreased. The results highlight the role of FAK in the progression of cancers. These findings suggest FAK serve as a potential therapeutic target for cancer therapy.

Dominant-negative Sox18 function inhibits dermal papilla maturation and differentiation in all murine hair types.

PubMed

Villani, Rehan; Hodgson, Samantha; Legrand, Julien; Greaney, Jessica; Wong, Ho Yi; Pichol-Thievend, Cathy; Adolphe, Christelle; Wainwight, Brandon; Francois, Mathias; Khosrotehrani, Kiarash

2017-05-15

SOX family proteins SOX2 and SOX18 have been reported as being essential in determining hair follicle type; however, the role they play during development remains unclear. Here, we demonstrate that Sox18 regulates the normal differentiation of the dermal papilla of all hair types. In guard (primary) hair dermal condensate (DC) cells, we identified transient Sox18 in addition to SOX2 expression at E14.5, which allowed fate tracing of primary DC cells until birth. Similarly, expression of Sox18 was detected in the DC cells of secondary hairs at E16.5 and in tertiary hair at E18.5. Dominant-negative Sox18 mutation (opposum) did not prevent DC formation in any hair type. However, it affected dermal papilla differentiation, restricting hair formation especially in secondary and tertiary hairs. This Sox18 mutation also prevented neonatal dermal cells or dermal papilla spheres from inducing hair in regeneration assays. Microarray expression studies identified WNT5A and TNC as potential downstream effectors of SOX18 that are important for epidermal WNT signalling. In conclusion, SOX18 acts as a mesenchymal molecular switch necessary for the formation and function of the dermal papilla in all hair types. © 2017. Published by The Company of Biologists Ltd.

Generation of chondrocytes from embryonic stem cells.

PubMed

Khillan, Jaspal Singh

2006-01-01

Pluripotent embryonic stem (ES) cells have complete potential for all the primary germ layers, such as ectoderm, mesoderm, and endoderm. However, the cellular and molecular mechanisms that control their lineage-restricted differentiation are not understood. Although embryoid bodies, which are formed because of the spontaneous differentiation of ES cells, have been used to study the differentiation into different cell types, including neurons, chondrocytes, insulin-producing cells, bone-forming cells, hematopoietic cells, and so on, this system has limitations for investigating the upstream events that lead to commitment of cells that occur during the inaccessible period of development. Recent developments in human ES cells have offered a challenge to develop strategies for understanding the basic mechanisms that play a key role in differentiation of stem cell into specific cell types for their applications in regenerative medicine and cell-based therapies. A micromass culture system was developed to induce the differentiation of ES cells into chondrocytes, the cartilage-producing cells, as a model to investigate the upstream events of stem cell differentiation. ES cells were co-cultured with limb bud progenitor cells. A high percentage of differentiated cells exhibit typical morphological characteristics of chondrocytes and express cartilage matrix genes such as collagen type II and proteoglycans, suggesting that signals from the progenitor cells are sufficient to induce ES cells into the chondrogenic lineage. Degeneration of cartilage in the joints is associated with osteoarthritis, which affects the quality of life of human patients. Therefore, the quantitative production of chondrocytes can be a powerful resource to alleviate the suffering of those patients.

Epstein-Barr virus (EBV) provides survival factors to EBV+ diffuse large B-cell lymphoma (DLBCL) lines and modulates cytokine induced specific chemotaxis in EBV+  DLBCL.

PubMed

Wu, Liang; Ehlin-Henriksson, Barbro; Zhou, Xiaoying; Zhu, Hong; Ernberg, Ingemar; Kis, Lorand L; Klein, George

2017-12-01

Diffuse large B-cell lymphoma (DLBCL), the most common type of malignant lymphoma, accounts for 30% of adult non-Hodgkin lymphomas. Epstein-Barr virus (EBV) -positive DLBCL of the elderly is a newly recognized subtype that accounts for 8-10% of DLBCLs in Asian countries, but is less common in Western populations. Five DLBCL-derived cell lines were employed to characterize patterns of EBV latent gene expression, as well as response to cytokines and chemotaxis. Interleukin-4 and interleukin-21 modified LMP1, EBNA1 and EBNA2 expression depending on cell phenotype and type of EBV latent programme (type I, II or III). These cytokines also affected CXCR4- or CCR7-mediated chemotaxis in two of the cell lines, Farage (type III) and Val (type II). Further, we investigated the effect of EBV by using dominant-negative EBV nuclear antigen 1(dnEBNA1) to eliminate EBV genomes. This resulted in decreased chemotaxis. By employing an alternative way to eliminate EBV genomes, Roscovitine, we show an increase of apoptosis in the EBV-positive lines. These results show that EBV plays an important role in EBV-positive DLBCL lines with regard to survival and chemotactic response. Our findings provide evidence for the impact of microenvironment on EBV-carrying DLBCL cells and might have therapeutic implications. © 2017 John Wiley & Sons Ltd.

Targeting glucagon receptor signalling in treating metabolic syndrome and renal injury in Type 2 diabetes: theory versus promise.

PubMed

Li, Xiao C; Zhuo, Jia L

2007-08-01

Pancreatic bi-hormones insulin and glucagon are the Yin and Yang in the regulation of glucose metabolism and homoeostasis. Insulin is synthesized primarily by pancreatic beta-cells and is released in response to an increase in blood glucose levels (hyperglycaemia). By contrast, glucagon is synthesized by pancreatic alpha-cells and is released in response to a decrease in blood glucose (hypoglycaemia). The principal role of glucagon is to counter the actions of insulin on blood glucose homoeostasis, but it also has diverse non-hyperglycaemic actions. Although Type 1 diabetes is caused by insulin deficiency (insulin-dependent) and can be corrected by insulin replacement, Type 2 diabetes is a multifactorial disease and its treatment is not dependent on insulin therapy alone. Type 2 diabetes in humans is characterized by increased insulin resistance, increased fasting blood glucose, impaired glucose tolerance and the development of glomerular hyperfiltration and microalbuminuria, ultimately leading to diabetic nephropathy and end-stage renal disease. Clinical studies have suggested that an inappropriate increase in hyperglycaemic glucagon (hyperglucagonaemia) over hypoglycaemic insulin (not insulin deficiency until advanced stages) plays an important role in the pathogenesis of Type 2 diabetes. However, for decades, research efforts and resources have been devoted overwhelmingly to studying the role of insulin and insulin-replacement therapy. By contrast, the implication of glucagon and its receptor signalling in the development of Type 2 diabetic metabolic syndromes and end-organ injury has received little attention. The aim of this review is to examine the evidence as to whether glucagon and its receptor signalling play any role(s) in the pathogenesis of Type 2 diabetic renal injury, and to explore whether targeting glucagon receptor signalling remains only a theoretical antidiabetic strategy in Type 2 diabetes or may realize its promise in the future.

The Pseudorabies Virus Glycoprotein gE/gI Complex Suppresses Type I Interferon Production by Plasmacytoid Dendritic Cells

PubMed Central

Lamote, Jochen A. S.; Kestens, Manon; Van Waesberghe, Cliff; Delva, Jonas; De Pelsmaeker, Steffi; Devriendt, Bert

2017-01-01

ABSTRACT Plasmacytoid dendritic cells (pDC) play a central role in the antiviral immune response, both in the innate response and in shaping the adaptive response, mainly because of their ability to produce massive amounts of type I interferon (TI-IFN). Here, we report that cells infected with the live attenuated Bartha vaccine strain of porcine alphaherpesvirus pseudorabies virus (PRV) trigger a dramatically increased TI-IFN response by porcine primary pDC compared to cells infected with wild-type PRV strains (Becker and Kaplan). Since Bartha is one of the relatively few examples of a highly successful alphaherpesvirus vaccine, identification of factors that may contribute to its efficacy may provide insights for the rational design of other alphaherpesvirus vaccines. The Bartha vaccine genome displays several mutations compared to the genome of wild-type PRV strains, including a large deletion in the unique short (US) region, encompassing the glycoprotein E (gE), gI, US9, and US2 genes. Using recombinant PRV Becker strains harboring the entire Bartha US deletion or single mutations in the four affected US genes, we demonstrate that the absence of the viral gE/gI complex contributes to the observed increased IFN-α response. Furthermore, we show that the absence of gE leads to an enhanced extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation in pDC, which correlates with a higher TI-IFN production by pDC. In conclusion, the PRV Bartha vaccine strain triggers strongly increased TI-IFN production by porcine pDC. Our data further indicate that the gE/gI glycoprotein complex suppresses TI-IFN production by pDC, which represents the first alphaherpesvirus factor that suppresses pDC activity. IMPORTANCE Several alphaherpesviruses, including herpes simpex virus, still lack effective vaccines. However, the highly successful Bartha vaccine has contributed substantially to eradication of the porcine alphaherpesvirus pseudorabies virus (PRV) in several countries. The impact of Bartha on the immune response is still poorly understood. Type I interferon (TI-IFN)-producing plasmacytoid dendritic cells (pDC) may play an important role in vaccine development. Here, we show that Bartha elicits a dramatically increased type I interferon (TI-IFN) response in primary porcine pDC compared to wild-type strains. In addition, we found that the gE/gI complex, which is absent in Bartha, inhibits the pDC TI-IFN response. This is the first description of an immune cell type that is differentially affected by Bartha versus wild-type PRV and is the first report describing an alphaherpesvirus protein that inhibits the TI-IFN response by pDC. These data may therefore contribute to the rational design of other alphaherpesvirus vaccines. PMID:28122975

The Pseudorabies Virus Glycoprotein gE/gI Complex Suppresses Type I Interferon Production by Plasmacytoid Dendritic Cells.

PubMed

Lamote, Jochen A S; Kestens, Manon; Van Waesberghe, Cliff; Delva, Jonas; De Pelsmaeker, Steffi; Devriendt, Bert; Favoreel, Herman W

2017-04-01

Plasmacytoid dendritic cells (pDC) play a central role in the antiviral immune response, both in the innate response and in shaping the adaptive response, mainly because of their ability to produce massive amounts of type I interferon (TI-IFN). Here, we report that cells infected with the live attenuated Bartha vaccine strain of porcine alphaherpesvirus pseudorabies virus (PRV) trigger a dramatically increased TI-IFN response by porcine primary pDC compared to cells infected with wild-type PRV strains (Becker and Kaplan). Since Bartha is one of the relatively few examples of a highly successful alphaherpesvirus vaccine, identification of factors that may contribute to its efficacy may provide insights for the rational design of other alphaherpesvirus vaccines. The Bartha vaccine genome displays several mutations compared to the genome of wild-type PRV strains, including a large deletion in the unique short (US) region, encompassing the glycoprotein E (gE), gI, US9, and US2 genes. Using recombinant PRV Becker strains harboring the entire Bartha US deletion or single mutations in the four affected US genes, we demonstrate that the absence of the viral gE/gI complex contributes to the observed increased IFN-α response. Furthermore, we show that the absence of gE leads to an enhanced extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation in pDC, which correlates with a higher TI-IFN production by pDC. In conclusion, the PRV Bartha vaccine strain triggers strongly increased TI-IFN production by porcine pDC. Our data further indicate that the gE/gI glycoprotein complex suppresses TI-IFN production by pDC, which represents the first alphaherpesvirus factor that suppresses pDC activity. IMPORTANCE Several alphaherpesviruses, including herpes simpex virus, still lack effective vaccines. However, the highly successful Bartha vaccine has contributed substantially to eradication of the porcine alphaherpesvirus pseudorabies virus (PRV) in several countries. The impact of Bartha on the immune response is still poorly understood. Type I interferon (TI-IFN)-producing plasmacytoid dendritic cells (pDC) may play an important role in vaccine development. Here, we show that Bartha elicits a dramatically increased type I interferon (TI-IFN) response in primary porcine pDC compared to wild-type strains. In addition, we found that the gE/gI complex, which is absent in Bartha, inhibits the pDC TI-IFN response. This is the first description of an immune cell type that is differentially affected by Bartha versus wild-type PRV and is the first report describing an alphaherpesvirus protein that inhibits the TI-IFN response by pDC. These data may therefore contribute to the rational design of other alphaherpesvirus vaccines. Copyright © 2017 American Society for Microbiology.

Indole-3-Acetic Acid Is Produced by Emiliania huxleyi Coccolith-Bearing Cells and Triggers a Physiological Response in Bald Cells.

PubMed

Labeeuw, Leen; Khey, Joleen; Bramucci, Anna R; Atwal, Harjot; de la Mata, A Paulina; Harynuk, James; Case, Rebecca J

2016-01-01

Indole-3-acetic acid (IAA) is an auxin produced by terrestrial plants which influences development through a variety of cellular mechanisms, such as altering cell orientation, organ development, fertility, and cell elongation. IAA is also produced by bacterial pathogens and symbionts of plants and algae, allowing them to manipulate growth and development of their host. They do so by either producing excess exogenous IAA or hijacking the IAA biosynthesis pathway of their host. The endogenous production of IAA by algae remains contentious. Using Emiliania huxleyi, a globally abundant marine haptophyte, we investigated the presence and potential role of IAA in algae. Homologs of genes involved in several tryptophan-dependent IAA biosynthesis pathways were identified in E. huxleyi. This suggests that this haptophyte can synthesize IAA using various precursors derived from tryptophan. Addition of L-tryptophan to E. huxleyi stimulated IAA production, which could be detected using Salkowski's reagent and GC × GC-TOFMS in the C cell type (coccolith bearing), but not in the N cell type (bald). Various concentrations of IAA were exogenously added to these two cell types to identify a physiological response in E. huxleyi. The N cell type, which did not produce IAA, was more sensitive to it, showing an increased variation in cell size, membrane permeability, and a corresponding increase in the photosynthetic potential quantum yield of Photosystem II (PSII). A roseobacter (bacteria commonly associated with E. huxleyi) Ruegeria sp. R11, previously shown to produce IAA, was co-cultured with E. huxleyi C and N cells. IAA could not be detected from these co-cultures, and even when stimulated by addition of L-tryptophan, they produced less IAA than axenic C type culture similarly induced. This suggests that IAA plays a novel role signaling between different E. huxleyi cell types, rather than between a bacteria and its algal host.

Measuring cell viscoelastic properties using a force-spectrometer: influence of protein-cytoplasm interactions

PubMed Central

Canetta, Elisabetta; Duperray, Alain; Leyrat, Anne; Verdier, Claude

2005-01-01

Cell adhesive and rheological properties play a very important role in cell transmigration through the endothelial barrier, in particular in the case of inflammation (leukocytes) or cancer metastasis (cancer cells). In order to characterize cell viscoelastic properties, we have designed a force spectrometer (AFM) which can stretch cells thereby allowing measurement of their rheological properties. This custom-made force spectrometer allows two different visualizations, one lateral and one from below. It allows investigation of the effects of rheology involved during cell stretching. To test the ability of our system to characterize such viscoelastic properties, ICAM-1 transfected CHO cells were analyzed. Two forms of ICAM-1 were tested; wild type ICAM-1, which can interact with the cytoskeleton, and a mutant form which lacks the cytoplasmic domain, and is unable to associate with the cytoskeleton. Stretching experiments carried out on these cells show the formation of long filaments. Using a previous model of filament elongation, we could determine the viscoelastic properties of a single cell. As expected, different viscoelastic components were found between the wild type and the mutant, which reveal that the presence of interactions between ICAM-1 and the cytoskeleton increases the stiffness of the cell. PMID:16308464

Measuring cell viscoelastic properties using a force-spectrometer: influence of protein-cytoplasm interactions.

PubMed

Canetta, Elisabetta; Duperray, Alain; Leyrat, Anne; Verdier, Claude

2005-01-01

Cell adhesive and rheological properties play a very important role in cell transmigration through the endothelial barrier, in particular in the case of inflammation (leukocytes) or cancer metastasis (cancer cells). In order to characterize cell viscoelastic properties, we have designed a force spectrometer (AFM) which can stretch cells thereby allowing measurement of their rheological properties. This custom-made force spectrometer allows two different visualizations, one lateral and one from below. It allows investigation of the effects of rheology involved during cell stretching. To test the ability of our system to characterize such viscoelastic properties, ICAM-1 transfected CHO cells were analyzed. Two forms of ICAM-1 were tested; wild type ICAM-1, which can interact with the cytoskeleton, and a mutant form which lacks the cytoplasmic domain, and is unable to associate with the cytoskeleton. Stretching experiments carried out on these cells show the formation of long filaments. Using a previous model of filament elongation, we could determine the viscoelastic properties of a single cell. As expected, different viscoelastic components were found between the wild type and the mutant, which reveal that the presence of interactions between ICAM-1 and the cytoskeleton increases the stiffness of the cell.

Activation of plasmacytoid dendritic cells with TLR9 agonists initiates invariant NKT cell-mediated cross-talk with myeloid dendritic cells.

PubMed

Montoya, Carlos J; Jie, Hyun-Bae; Al-Harthi, Lena; Mulder, Candice; Patiño, Pablo J; Rugeles, María T; Krieg, Arthur M; Landay, Alan L; Wilson, S Brian

2006-07-15

CD1d-restricted invariant NK T (iNKT) cells and dendritic cells (DCs) have been shown to play crucial roles in various types of immune responses, including TLR9-dependent antiviral responses initiated by plasmacytoid DCs (pDCs). However, the mechanism by which this occurs is enigmatic because TLRs are absent in iNKT cells and human pDCs do not express CD1d. To explore this process, pDCs were activated with CpG oligodeoxyribonucleotides, which stimulated the secretion of several cytokines such as type I and TNF-alpha. These cytokines and other soluble factors potently induced the expression of activation markers on iNKT cells, selectively enhanced double-negative iNKT cell survival, but did not induce their expansion or production of cytokines. Notably, pDC-derived factors licensed iNKT cells to respond to myeloid DCs: an important downstream cellular target of iNKT cell effector function and a critical contributor to the initiation of adaptive immune responses. This interaction supports the notion that iNKT cells can mediate cross-talk between DC subsets known to express mutually exclusive TLR and cytokine profiles.

Pathogenic or Therapeutic Extracellular Vesicles in Rheumatic Diseases: Role of Mesenchymal Stem Cell-Derived Vesicles

PubMed Central

Cosenza, Stella; Ruiz, Maxime; Maumus, Marie; Jorgensen, Christian; Noël, Danièle

2017-01-01

Extracellular vesicles (EVs) are important mediators of cell-to-cell communication pathways via the transport of proteins, mRNA, miRNA and lipids. There are three main types of EVs, exosomes, microparticles and apoptotic bodies, which are classified according to their size and biogenesis. EVs are secreted by all cell types and their function reproduces that of the parental cell. They are involved in many biological processes that regulate tissue homeostasis and physiopathology of diseases. In rheumatic diseases, namely osteoarthritis (OA) and rheumatoid arthritis (RA), EVs have been isolated from synovial fluid and shown to play pathogenic roles contributing to progression of both diseases. By contrast, EVs may have therapeutic effect via the delivery of molecules that may stop disease evolution. In particular, EVs derived from mesenchymal stem cells (MSCs) reproduce the main functions of the parental cells and therefore represent the ideal type of EVs for modulating the course of either disease. The aim of this review is to discuss the role of EVs in OA and RA focusing on their potential pathogenic effect and possible therapeutic options. Special attention is given to MSCs and MSC-derived EVs for modulating OA and RA progression with the perspective of developing innovative therapeutic strategies. PMID:28441721

PATHOPHYSIOLOGY AND TREATMENT OF TYPE 2 DIABETES: PERSPECTIVES ON THE PAST, PRESENT AND FUTURE

PubMed Central

Kahn, Steven E.; Cooper, Mark E.; Del Prato, Stefano

2014-01-01

Normal regulation of glucose metabolism is determined by a feedback loop involving the islet β-cell and insulin-sensitive tissues in which tissue sensitivity to insulin determines the magnitude of the β-cell response. When insulin resistance is present, the β-cell maintains normal glucose tolerance by increasing insulin output. It is only when the β-cell is incapable of releasing sufficient insulin in the presence of insulin resistance that glucose levels rise. While β-cell dysfunction has a clear genetic component, environmental changes play a vital role. Modern approaches have also informed regarding the importance of hexoses, amino acids and fatty acids in determining insulin resistance and β-cell dysfunction as well as the potential role of alterations in the microbiome. A number of new treatment approaches have been developed, but more effective therapies that slow the progressive loss of β-cell function are needed. Recent clinical trials have provided important information regarding approaches to prevent and treat type 2 diabetes as well as some of the adverse effects of these interventions. However, additional long-term studies of medications and bariatric surgery are required in order to identify novel approaches to prevention and treatment, thereby reducing the deleterious impact of type 2 diabetes. PMID:24315620

Minireview: Emerging Roles for Extracellular Vesicles in Diabetes and Related Metabolic Disorders

PubMed Central

Lakhter, Alexander J.

2015-01-01

Extracellular vesicles (EVs), membrane-contained vesicles released by most cell types, have attracted a large amount of research interest over the past decade. Because of their ability to transfer cargo via regulated processes, causing functional impacts on recipient cells, these structures may play important roles in cell-cell communication and have implications in the physiology of numerous organ systems. In addition, EVs have been described in most human biofluids and have wide potential as relatively noninvasive biomarkers of various pathologic conditions. Specifically, EVs produced by the pancreatic β-cell have been demonstrated to regulate physiologic and pathologic responses to β-cell stress, including β-cell proliferation and apoptosis. β-Cell EVs are also capable of interacting with immune cells and may contribute to the activation of autoimmune processes that trigger or propagate β-cell inflammation and destruction during the development of diabetes. EVs from adipose tissue have been shown to contribute to the development of the chronic inflammation and insulin resistance associated with obesity and metabolic syndrome via interactions with other adipose, liver, and muscle cells. Circulating EVs may also serve as biomarkers for metabolic derangements and complications associated with diabetes. This minireview describes the properties of EVs in general, followed by a more focused review of the literature describing EVs affecting the β-cell, β-cell autoimmunity, and the development of insulin resistance, which all have the potential to affect development of type 1 or type 2 diabetes. PMID:26393296

Cisplatin-induced Casepase-3 activation in different tumor cells

NASA Astrophysics Data System (ADS)

Shi, Hua; Li, Xiao; Su, Ting; Zhang, Yu-Hai

2008-12-01

Apoptosis plays an essential role in normal organism development which is one of the main types of programmed cell death to help tissues maintain homeostasis. Defective apoptosis can result in cell accumulation and therefore effects on tumor pathogenesis, progression and therapy resistance. A family of proteins, known as caspases, is typically activated in the early stages of apoptosis. Therefore, studying the kinetics of activation of caspases induced by antitumor drugs can contribute to antitumor drug discovery and explanation of the molecular mechanisms. This paper detected the Caspase-3 activity induced by cisplatin in human adenoid cystic carcinoma cell line (ACC-M), human hepatocellular liver carcinoma cell line (HepG2) and human epithelial carcinoma cell line (Hela) with stably expressing ECFP-DEVDDsRed (CD3) probe, a fluorescent probe consisting of Enhanced Cyan Fluorescent Protein (ECFP), red fluorescent protein (DsRed) and a linker with a recognition site of Caspase-3, by using the capillary electrophoresis (CE) and fluorescence resonance energy transfer (FRET) imaging system. Under the same concentration of cisplatin, ACC-M cells responded the most rapidly, and then HepG2 cells and Hela cells, respectively, in the early 30 hours. Later, HepG2 cells represented acceleration in the Caspase-3 activation speed and reached full activation the earliest comparing to other two cell types. The results demonstrated that ACC-M cell is more sensitive than the other two cell types under the treatment of cisplatin.

Human eosinophils modulate peripheral blood mononuclear cell response to Schistosoma mansoni adult worm antigen in vitro.

PubMed

Tweyongyere, R; Namanya, H; Naniima, P; Cose, S; Tukahebwa, E M; Elliott, A M; Dunne, D W; Wilson, S

2016-08-01

High numbers of eosinophils are observed in parasitic infections and allergic diseases, where they are proposed to be terminally differentiated effector cells that play beneficial role in host defence, or cause harmful inflammatory response. Eosinophils have been associated with killing of schistosomulae in vitro, but there is growing evidence that eosinophils can play additional immuno-regulatory role. Here, we report results of a study that examines peripheral blood mononuclear cell (PBMC) cytokine responses to Schistosoma mansoni adult worm antigen (SWA) when stimulated alone or enriched with autologous eosinophils. Production of the Th-2 type cytokines interleukin (IL)-4, IL-5 and IL-13 was lower (P = 0·017, 0·018 and <0·001, respectively) in PBMC + eosinophil cultures than in PBMC-only cultures stimulated with SWA. Substantial levels of IL-13, IL-10, interferon gamma and tumour necrosis factor alpha were recorded in cultures of eosinophils, but none of these cytokines showed significant association with the observed eosinophil-induced drop in cytokine responses of PBMC. Transwell experiments suggested that the observed effect is due to soluble mediators that downmodulate production of Th-2 type cytokines. This study shows that eosinophils may down-modulate schistosome-specific Th-2 type cytokine responses in S. mansoni-infected individuals. The mechanism of this immune modulation remains to be elucidated. © 2016 The Authors. Parasite Immunology Published by John Wiley & Sons Ltd.

Genome-wide expression profiling analysis to identify key genes in the anti-HIV mechanism of CD4+ and CD8+ T cells.

PubMed

Gao, Lijie; Wang, Yunqi; Li, Yi; Dong, Ya; Yang, Aimin; Zhang, Jie; Li, Fengying; Zhang, Rongqiang

2018-07-01

Comprehensive bioinformatics analyses were performed to explore the key biomarkers in response to HIV infection of CD4 + and CD8 + T cells. The numbers of CD4 + and CD8 + T cells of HIV infected individuals were analyzed and the GEO database (GSE6740) was screened for differentially expressed genes (DEGs) in HIV infected CD4 + and CD8 + T cells. Gene Ontology enrichment, KEGG pathway analyses, and protein-protein interaction (PPI) network were performed to identify the key pathway and core proteins in anti-HIV virus process of CD4 + and CD8 + T cells. Finally, we analyzed the expressions of key proteins in HIV-infected T cells (GSE6740 dataset) and peripheral blood mononuclear cells(PBMCs) (GSE511 dataset). 1) CD4 + T cells counts and ratio of CD4 + /CD8 + T cells decreased while CD8 + T cells counts increased in HIV positive individuals; 2) 517 DEGs were found in HIV infected CD4 + and CD8 + T cells at acute and chronic stage with the criterial of P-value <0.05 and fold change (FC) ≥2; 3) In acute HIV infection, type 1 interferon (IFN-1) pathway might played a critical role in response to HIV infection of T cells. The main biological processes of the DEGs were response to virus and defense response to virus. At chronic stage, ISG15 protein, in conjunction with IFN-1 pathway might play key roles in anti-HIV responses of CD4 + T cells; and 4) The expression of ISG15 increased in both T cells and PBMCs after HIV infection. Gene expression profile of CD4 + and CD8 + T cells changed significantly in HIV infection, in which ISG15 gene may play a central role in activating the natural antiviral process of immune cells. © 2018 Wiley Periodicals, Inc.

Failure in activation of the canonical NF-κB pathway by human T-cell leukemia virus type 1 Tax in non-hematopoietic cell lines

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

Mizukoshi, Terumi; Komori, Hideyuki; Mizuguchi, Mariko

2013-09-01

Human T-cell leukemia virus type 1 (HTLV-1) Tax (Tax1) plays crucial roles in leukemogenesis in part through activation of NF-κB. In this study, we demonstrated that Tax1 activated an NF-κB binding (gpκB) site of the gp34/OX40 ligand gene in a cell type-dependent manner. Our examination showed that the gpκΒ site and authentic NF-κB (IgκB) site were activated by Tax1 in hematopoietic cell lines. Non-hematopoietic cell lines including hepatoma and fibroblast cell lines were not permissive to Tax1-mediated activation of the gpκB site, while the IgκB site was activated in those cells in association with binding of RelB. However RelA bindingmore » was not observed in the gpκB and IgκB sites. Our results suggest that HTLV-1 Tax1 fails to activate the canonical pathway of NF-κB in non-hematopoietic cell lines. Cell type-dependent activation of NF-κB by Tax1 could be associated with pathogenesis by HTLV-1 infection. - Highlights: • HTLV-1 Tax1 does not activate RelA of NF-κB in non-hematopoietic cell lines. • Tax1 activates the NF-κB non-canonical pathway in non-hematopoietic cell lines. • Tax1 does not induce RelA nuclear translocation in those cell lines, unlike TNFα. • The OX40L promoter κB site is activated by ectopic, but not endogenous, RelA.« less

Accelerating molecular dynamic simulation on the cell processor and Playstation 3.

PubMed

Luttmann, Edgar; Ensign, Daniel L; Vaidyanathan, Vishal; Houston, Mike; Rimon, Noam; Øland, Jeppe; Jayachandran, Guha; Friedrichs, Mark; Pande, Vijay S

2009-01-30

Implementation of molecular dynamics (MD) calculations on novel architectures will vastly increase its power to calculate the physical properties of complex systems. Herein, we detail algorithmic advances developed to accelerate MD simulations on the Cell processor, a commodity processor found in PlayStation 3 (PS3). In particular, we discuss issues regarding memory access versus computation and the types of calculations which are best suited for streaming processors such as the Cell, focusing on implicit solvation models. We conclude with a comparison of improved performance on the PS3's Cell processor over more traditional processors. (c) 2008 Wiley Periodicals, Inc.

Interrelated striated elements in vestibular hair cells of the rat

NASA Technical Reports Server (NTRS)

Ross, M. D.; Bourne, C.

1983-01-01

A series of interrelated striated organelles in types I and II vestibular hair cells of the rat which appear to be less developed in cochlear hair cells have been revealed by unusual fixation procedures, suggesting that contractile elements may play a role in sensory transduction in the inner ear, especially in the vestibular system. Included in the series of interrelated striated elements are the cuticular plate and its basal attachments to the hair cell margins, the connections of the strut array of the kinociliary basal body to the cuticular plate, and striated organelles associated with the plasma membrane and extending below the apical junctional complexes.

Differential expression of islet glutaredoxin 1 and 5 with high reactive oxygen species production in a mouse model of diabesity.

PubMed

Petry, Sebastian Friedrich; Sharifpanah, Fatemeh; Sauer, Heinrich; Linn, Thomas

2017-01-01

The onset and progression of diabetes mellitus type 2 is highly contingent on the amount of functional beta-cell mass. An underlying cause of beta-cell decay in diabetes is oxidative stress, which markedly affects the insulin producing pancreatic cells due to their poor antioxidant defence capacity. Consequently, disturbances of cellular redox signaling have been implicated to play a major role in beta-cell loss in diabetes mellitus type 2. There is evidence suggesting that the glutaredoxin (Grx) system exerts a protective role for pancreatic islets, but the exact mechanisms have not yet been elucidated. In this study, a mouse model for diabetes mellitus type 2 was used to gain further insight into the significance of Grx for the islets of Langerhans in the diabetic metabolism. We have observed distinct differences in the expression levels of Grx in pancreatic islets between obese, diabetic db mice and lean, non-diabetic controls. This finding is the first report about a decrease of Grx expression levels in pancreatic islets of diabetic mice which was accompanied by declining insulin secretion, increase of reactive oxygen species (ROS) production level, and cell cycle alterations. These data demonstrate the essential role of the Grx system for the beta-cell during metabolic stress which may provide a new target for diabetes mellitus type 2 treatment.

Contractility in type III cochlear fibrocytes is dependent on non-muscle myosin II and intercellular gap junctional coupling.

PubMed

Kelly, John J; Forge, Andrew; Jagger, Daniel J

2012-08-01

The cochlear spiral ligament is a connective tissue that plays diverse roles in normal hearing. Spiral ligament fibrocytes are classified into functional sub-types that are proposed to carry out specialized roles in fluid homeostasis, the mediation of inflammatory responses to trauma, and the fine tuning of cochlear mechanics. We derived a secondary sub-culture from guinea pig spiral ligament, in which the cells expressed protein markers of type III or "tension" fibrocytes, including non-muscle myosin II (nmII), α-smooth muscle actin (αsma), vimentin, connexin43 (cx43), and aquaporin-1. The cells formed extensive stress fibers containing αsma, which were also associated intimately with nmII expression, and the cells displayed the mechanically contractile phenotype predicted by earlier modeling studies. cx43 immunofluorescence was evident within intercellular plaques, and the cells were coupled via dye-permeable gap junctions. Coupling was blocked by meclofenamic acid (MFA), an inhibitor of cx43-containing channels. The contraction of collagen lattice gels mediated by the cells could be prevented reversibly by blebbistatin, an inhibitor of nmII function. MFA also reduced the gel contraction, suggesting that intercellular coupling modulates contractility. The results demonstrate that these cells can impart nmII-dependent contractile force on a collagenous substrate, and support the hypothesis that type III fibrocytes regulate tension in the spiral ligament-basilar membrane complex, thereby determining auditory sensitivity.

A Special Connection between γδ T Cells and Natural Antibodies?

PubMed Central

Born, Willi K.; Huang, Yafei; Zeng, Wanjiang; Torres, Raul M.; O’Brien, Rebecca L.

2017-01-01

Natural antibodies (NAbs) play an important role in early host defense, autophagy and tissue remodeling, and in immune regulation. They arise spontaneously (without specific immunization), and are already present at birth. NAbs are produced by B1 B cells, MZ B cells and other B cell types. They include all major Ig subclasses but IgM antibodies are prevalent, especially early in development. NAbs may be poly-specific, recognize particular auto-antigens, or detect neo-determinants such as those exposed during apoptosis or generated by oxidation. NAbs do not require cognate T cell help but depend on soluble mediators produced by T cells. Our recent studies suggest that γδ T cells may have a special relationship with NAbs, and play a prominent role in their regulation, in part through the fine-tuning of IL-4-levels. The spontaneously activated state of these cells likely enables their cytokine production and other functions in the absence of external stimulation. Ontogenetically, the earlier arising γδ T cells are better positioned than αβ T cells to shape the developing repertoire of NAbs. Intriguingly, ligand specificities of NAbs and γδ T cell receptors appear to be overlapping, perhaps allowing γδ cognate help for certain NAb specificities. Via NAbs, γδ T cells could exert a regulatory influence on numerous processes in health and disease. PMID:27235134

On the track of transfer cell formation by specialized plant-parasitic nematodes.

PubMed

Rodiuc, Natalia; Vieira, Paulo; Banora, Mohamed Youssef; de Almeida Engler, Janice

2014-01-01

Transfer cells are ubiquitous plant cells that play an important role in plant development as well as in responses to biotic and abiotic stresses. They are highly specialized and differentiated cells playing a central role in the acquisition, distribution and exchange of nutrients. Their unique structural traits are characterized by augmented ingrowths of invaginated secondary wall material, unsheathed by an amplified area of plasma membrane enriched in a suite of solute transporters. Similar morphological features can be perceived in vascular root feeding cells induced by sedentary plant-parasitic nematodes, such as root-knot and cyst nematodes, in a wide range of plant hosts. Despite their close phylogenetic relationship, these obligatory biotrophic plant pathogens engage different approaches when reprogramming root cells into giant cells or syncytia, respectively. Both nematode feeding-cells types will serve as the main source of nutrients until the end of the nematode life cycle. In both cases, these nematodes are able to remarkably maneuver and reprogram plant host cells. In this review we will discuss the structure, function and formation of these specialized multinucleate cells that act as nutrient transfer cells accumulating and synthesizing components needed for survival and successful offspring of plant-parasitic nematodes. Plant cells with transfer-like functions are also a renowned subject of interest involving still poorly understood molecular and cellular transport processes.

A Special Connection between γδ T Cells and Natural Antibodies?

PubMed

Born, Willi K; Huang, Yafei; Zeng, Wanjiang; Torres, Raul M; O'Brien, Rebecca L

2016-12-01

Natural antibodies (NAbs) play an important role in early host defense, autophagy and tissue remodeling, and in immune regulation. They arise spontaneously (without specific immunization), and are already present at birth. NAbs are produced by B1 B cells, MZ B cells and other B cell types. They include all major Ig subclasses but IgM antibodies are prevalent, especially early in development. NAbs may be poly-specific, recognize particular auto-antigens, or detect neo-determinants such as those exposed during apoptosis or generated by oxidation. NAbs do not require cognate T cell help but depend on soluble mediators produced by T cells. Our recent studies suggest that γδ T cells may have a special relationship with NAbs, and play a prominent role in their regulation, in part through the fine-tuning of IL-4 levels. The spontaneously activated state of these cells likely enables their cytokine production and other functions in the absence of external stimulation. Ontogenetically, the earlier arising γδ T cells are better positioned than αβ T cells to shape the developing repertoire of NAbs. Intriguingly, ligand specificities of NAbs and γδ T cell receptors appear to be overlapping, perhaps allowing γδ cognate help for certain NAb specificities. Via NAbs, γδ T cells could exert a regulatory influence on numerous processes in health and disease.

The EphA2 Receptor and EphrinA1 Ligand in Solid Tumors: Function and Therapeutic Targeting

PubMed Central

Wykosky, Jill; Debinski, Waldemar

2013-01-01

The Eph receptor tyrosine kinases and ephrin ligands have been studied extensively for their roles in developmental processes. In recent years, Eph receptors and ephrins have been found to be integral players in cancer formation and progression. Among these are EphA2 and ephrinA1, which are involved in the development and maintenance of many different types of solid tumors. The function of EphA2 and ephrinA1 in tumorigenesis and tumor progression is complex and seems to be dependent on cell type and microenvironment. These variables affect the expression of the EphA2 and ephrinA1 proteins, the pathways through which they induce signaling, and the functional consequences of that signaling on the behavior of tumor cells and tumor-associated cells. This review will specifically focus on the roles that EphA2 and ephrinA1 play in the different cell types that contribute to the malignancy of solid tumors, with emphasis on the opportunities for therapeutic targeting. PMID:19074825

The Plasma Membrane Calcium ATPases and Their Role as Major New Players in Human Disease.

PubMed

Stafford, Nicholas; Wilson, Claire; Oceandy, Delvac; Neyses, Ludwig; Cartwright, Elizabeth J

2017-07-01

The Ca 2+ extrusion function of the four mammalian isoforms of the plasma membrane calcium ATPases (PMCAs) is well established. There is also ever-increasing detail known of their roles in global and local Ca 2+ homeostasis and intracellular Ca 2+ signaling in a wide variety of cell types and tissues. It is becoming clear that the spatiotemporal patterns of expression of the PMCAs and the fact that their abundances and relative expression levels vary from cell type to cell type both reflect and impact on their specific functions in these cells. Over recent years it has become increasingly apparent that these genes have potentially significant roles in human health and disease, with PMCAs1-4 being associated with cardiovascular diseases, deafness, autism, ataxia, adenoma, and malarial resistance. This review will bring together evidence of the variety of tissue-specific functions of PMCAs and will highlight the roles these genes play in regulating normal physiological functions and the considerable impact the genes have on human disease. Copyright © 2017 the American Physiological Society.

Fundamentals of pulmonary drug delivery.

PubMed

Groneberg, D A; Witt, C; Wagner, U; Chung, K F; Fischer, A

2003-04-01

Aerosol administration of peptide-based drugs plays an important role in the treatment of pulmonary and systemic diseases and the unique cellular properties of airway epithelium offers a great potential to deliver new compounds. As the relative contributions from the large airways to the alveolar space are important to the local and systemic availability, the sites and mechanism of uptake and transport of different target compounds have to be characterized. Among the different respiratory cells, the ciliated epithelial cells of the larger and smaller airways and the type I and type II pneumocytes are the key players in pulmonary drug transport. With their diverse cellular characteristics, each of these cell types displays a unique uptake possibility. Next to the knowledge of these cellular aspects, the nature of aerosolized drugs, characteristics of delivery systems and the depositional and pulmonary clearance mechanisms display major targets to optimize pulmonary drug delivery. Based on the growing knowledge on pulmonary cell biology and pathophysiology due to modern methods of molecular biology, the future characterization of pulmonary drug transport pathways can lead to new strategies in aerosol drug therapy.

Non-ideal Solution Thermodynamics of Cytoplasm

PubMed Central

Ross-Rodriguez, Lisa U.; McGann, Locksley E.

2012-01-01

Quantitative description of the non-ideal solution thermodynamics of the cytoplasm of a living mammalian cell is critically necessary in mathematical modeling of cryobiology and desiccation and other fields where the passive osmotic response of a cell plays a role. In the solution thermodynamics osmotic virial equation, the quadratic correction to the linear ideal, dilute solution theory is described by the second osmotic virial coefficient. Herein we report, for the first time, intracellular solution second osmotic virial coefficients for four cell types [TF-1 hematopoietic stem cells, human umbilical vein endothelial cells (HUVEC), porcine hepatocytes, and porcine chondrocytes] and further report second osmotic virial coefficients indistinguishable from zero (for the concentration range studied) for human hepatocytes and mouse oocytes. PMID:23840923

Cot kinase plays a critical role in Helicobacter pylori-induced IL-8 expression.

PubMed

Jang, Sungil; Kim, Jinmoon; Cha, Jeong-Heon

2017-04-01

Helicobacter pylori is a major pathogen causing various gastric diseases including gastric cancer. Infection of H. pylori induces pro-inflammatory cytokine IL-8 expression in gastric epithelial cells in the initial inflammatory process. It has been known that H. pylori can modulate Ras-Raf-Mek-Erk signal pathway for IL-8 induction. Recently, it has been shown that another signal molecule, cancer Osaka thyroid oncogene/tumor progression locus 2 (Cot/Tpl2) kinase, activates Mek and Erk and plays a role in the Erk pathway, similar to MAP3K signal molecule Raf kinase. Therefore, the objective of this study was to determine whether Cot kinase might be involved in IL-8 induction caused by H. pylori infection. AGS gastric epithelial cells were infected by H. pylori strain G27 or its isogenic mutants lacking cagA or type IV secretion system followed by treatment with Cot kinase inhibitor (KI) or siRNA specific for Cot kinase. Activation of Erk was assessed by Western blot analysis and expression of IL-8 was measured by ELISA. Treatment with Cot KI reduced both transient and sustained Erk activation. It also reduced early and late IL-8 secretion in the gastric epithelial cell line. Furthermore, siRNA knockdown of Cot inhibited early and late IL-8 secretion induced by H. pylori infection. Taken together, these results suggest that Cot kinase might play a critical role in H. pylori type IV secretion apparatus-dependent early IL-8 secretion and CagA-dependent late IL-8 secretion as an alternative signaling molecule in the Erk pathway.

Effect with high density nano dot type storage layer structure on 20 nm planar NAND flash memory characteristics

NASA Astrophysics Data System (ADS)

Sasaki, Takeshi; Muraguchi, Masakazu; Seo, Moon-Sik; Park, Sung-kye; Endoh, Tetsuo

2014-01-01

The merits, concerns and design principle for the future nano dot (ND) type NAND flash memory cell are clarified, by considering the effect of storage layer structure on NAND flash memory characteristics. The characteristics of the ND cell for a NAND flash memory in comparison with the floating gate type (FG) is comprehensively studied through the read, erase, program operation, and the cell to cell interference with device simulation. Although the degradation of the read throughput (0.7% reduction of the cell current) and slower program time (26% smaller programmed threshold voltage shift) with high density (10 × 1012 cm-2) ND NAND are still concerned, the suppress of the cell to cell interference with high density (10 × 1012 cm-2) plays the most important part for scaling and multi-level cell (MLC) operation in comparison with the FG NAND. From these results, the design knowledge is shown to require the control of the number of nano dots rather than the higher nano dot density, from the viewpoint of increasing its memory capacity by MLC operation and suppressing threshold voltage variability caused by the number of dots in the storage layer. Moreover, in order to increase its memory capacity, it is shown the tunnel oxide thickness with ND should be designed thicker (>3 nm) than conventional designed ND cell for programming/erasing with direct tunneling mechanism.

SVCT2 vitamin C transporter expression in progenitor cells of the postnatal neurogenic niche

PubMed Central

Pastor, Patricia; Cisternas, Pedro; Salazar, Katterine; Silva-Alvarez, Carmen; Oyarce, Karina; Jara, Nery; Espinoza, Francisca; Martínez, Agustín D.; Nualart, Francisco

2013-01-01

Known as a critical antioxidant, recent studies suggest that vitamin C plays an important role in stem cell generation, proliferation and differentiation. Vitamin C also enhances neural differentiation during cerebral development, a function that has not been studied in brain precursor cells. We observed that the rat neurogenic niche is structurally organized at day 15 of postnatal development, and proliferation and neural differentiation increase at day 21. In the human brain, a similar subventricular niche was observed at 1-month of postnatal development. Using immunohistochemistry, sodium-vitamin C cotransporter 2 (SVCT2) expression was detected in the subventricular zone (SVZ) and rostral migratory stream (RMS). Low co-distribution of SVCT2 and βIII-tubulin in neuroblasts or type-A cells was detected, and minimal co-localization of SVCT2 and GFAP in type-B or precursor cells was observed. Similar results were obtained in the human neurogenic niche. However, BrdU-positive cells also expressed SVCT2, suggesting a role of vitamin C in neural progenitor proliferation. Primary neurospheres prepared from rat brain and the P19 teratocarcinoma cell line, which forms neurospheres in vitro, were used to analyze the effect of vitamin C in neural stem cells. Both cell types expressed functional SVCT2 in vitro, and ascorbic acid (AA) induced their neural differentiation, increased βIII-tubulin and SVCT2 expression, and amplified vitamin C uptake. PMID:23964197

Tumor budding cells, cancer stem cells and epithelial-mesenchymal transition-type cells in pancreatic cancer.

PubMed

Karamitopoulou, Eva

2012-01-01

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers with a 5-year survival rate of less than 5%. Moreover, PDAC escapes early detection and resists treatment. Multiple combinations of genetic alterations are known to occur in PDAC including mutational activation of KRAS, inactivation of p16/CDKN2A and SMAD4 (DPC4) and dysregulation of PTEN/PI3K/AKT signaling. Through their interaction with Wingless-INT pathway, the downstream molecules of these pathways have been implicated in the promotion of epithelial-mesenchymal transition (EMT). Emerging evidence has demonstrated that cancer stem cells (CSCs), small populations of which have been identified in PDAC, and EMT-type cells play critical roles in drug resistance, invasion, and metastasis in pancreatic cancer. EMT may be histologically represented by the presence of tumor budding which is described as the occurrence of single tumor cells or small clusters (<5) of dedifferentiated cells at the invasive front of gastrointestinal (including colorectal, oesophageal, gastric, and ampullary) carcinomas and is linked to poor prognosis. Tumor budding has recently been shown to occur frequently in PDAC and to be associated with adverse clinicopathological features and decreased disease-free and overall survival. The aim of this review is to present a short overview on the morphological and molecular aspects that underline the relationship between tumor budding cells, CSCs, and EMT-type cells in PDAC.

Glucocorticoid action in human corneal epithelial cells establishes roles for corticosteroids in wound healing and barrier function of the eye.

PubMed

Kadmiel, Mahita; Janoshazi, Agnes; Xu, Xiaojiang; Cidlowski, John A

2016-11-01

Glucocorticoids play diverse roles in almost all physiological systems of the body, including both anti-inflammatory and immunosuppressive roles. Synthetic glucocorticoids are one of the most widely prescribed drugs and are used in the treatment of conditions such as autoimmune diseases, allergies, ocular disorders and certain types of cancers. In the interest of investigating glucocorticoid actions in the cornea of the eye, we established that multiple cell types in mouse corneas express functional glucocorticoid receptor (GR) with corneal epithelial cells having robust expression. To define glucocorticoid actions in a cell type-specific manner, we employed immortalized human corneal epithelial (HCE) cell line to define the glucocorticoid transcriptome and elucidated its functions in corneal epithelial cells. Over 4000 genes were significantly regulated within 6 h of dexamethasone treatment, and genes associated with cell movement, cytoskeletal remodeling and permeability were highly regulated. Real-time in vitro wound healing assays revealed that glucocorticoids delay wound healing by attenuating cell migration. These functional alterations were associated with cytoskeletal remodeling at the wounded edge of a scratch-wounded monolayer. However, glucocorticoid treatment improved the organization of tight-junction proteins and enhanced the epithelial barrier function. Our results demonstrate that glucocorticoids profoundly alter corneal epithelial gene expression and many of these changes likely impact both wound healing and epithelial cell barrier function. Published by Elsevier Ltd.

Rap G protein signal in normal and disordered lymphohematopoiesis

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

Minato, Nagahiro, E-mail: minato@imm.med.kyoto-u.ac.jp

2013-09-10

Rap proteins (Rap1, Rap2a, b, c) are small molecular weight GTPases of the Ras family. Rap G proteins mediate diverse cellular events such as cell adhesion, proliferation, and gene activation through various signaling pathways. Activation of Rap signal is regulated tightly by several specific regulatory proteins including guanine nucleotide exchange factors and GTPase-activating proteins. Beyond cell biological studies, increasing attempts have been made in the past decade to define the roles of Rap signal in specific functions of normal tissue systems as well as in cancer. In the immune and hematopoietic systems, Rap signal plays crucial roles in the developmentmore » and function of essentially all lineages of lymphocytes and hematopoietic cells, and importantly, deregulated Rap signal may lead to unique pathological conditions depending on the affected cell types, including various types of leukemia and autoimmunity. The phenotypical studies have unveiled novel, even unexpected functional aspects of Rap signal in cells from a variety of tissues, providing potentially important clues for controlling human diseases, including malignancy.« less

PPARγ and Apoptosis in Cancer

PubMed Central

Elrod, Heath A.; Sun, Shi-Yong

2008-01-01

Peroxisome proliferator-activated receptors (PPARs) are ligand binding transcription factors which function in many physiological roles including lipid metabolism, cell growth, differentiation, and apoptosis. PPARs and their ligands have been shown to play a role in cancer. In particular, PPARγ ligands including endogenous prostaglandins and the synthetic thiazolidinediones (TZDs) can induce apoptosis of cancer cells with antitumor activity. Thus, PPARγ ligands have a potential in both chemoprevention and therapy of several types of cancer either as single agents or in combination with other antitumor agents. Accordingly, the involvement of PPARγ and its ligands in regulation of apoptosis of cancer cells have been extensively studied. Depending on cell types or ligands, induction of apoptosis in cancer cells by PPARγ ligands can be either PPARγ-dependent or -independent. Through increasing our understanding of the mechanisms of PPARγ ligand-induced apoptosis, we can develop better strategies which may include combining other antitumor agents for PPARγ-targeted cancer chemoprevention and therapy. This review will highlight recent research advances on PPARγ and apoptosis in cancer. PMID:18615184

The cell-mediated immunity of Drosophila melanogaster: hemocyte lineages, immune compartments, microanatomy and regulation.

PubMed

Honti, Viktor; Csordás, Gábor; Kurucz, Éva; Márkus, Róbert; Andó, István

2014-01-01

In the animal kingdom, innate immunity is the first line of defense against invading pathogens. The dangers of microbial and parasitic attacks are countered by similar mechanisms, involving the prototypes of the cell-mediated immune responses, the phagocytosis and encapsulation. Work on Drosophila has played an important role in promoting an understanding of the basic mechanisms of phylogenetically conserved modules of innate immunity. The aim of this review is to survey the developments in the identification and functional definition of immune cell types and the immunological compartments of Drosophila melanogaster. We focus on the molecular and developmental aspects of the blood cell types and compartments, as well as the dynamics of blood cell development and the immune response. Further advances in the characterization of the innate immune mechanisms in Drosophila will provide basic clues to the understanding of the importance of the evolutionary conserved mechanisms of innate immune defenses in the animal kingdom. Copyright © 2013 Elsevier Ltd. All rights reserved.

Cytoplasmic sequestration of cyclin D1 associated with cell cycle withdrawal of neuroblastoma cells

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

Sumrejkanchanakij, Piyamas; Department of Anatomy, Faculty of Dentistry, Chulalongkorn University, Bangkok 10330; Eto, Kazuhiro

2006-02-03

The regulation of D-type cyclin-dependent kinase activity is critical for neuronal differentiation and apoptosis. We recently showed that cyclin D1 is sequestered in the cytoplasm and that its nuclear localization induces apoptosis in postmitotic primary neurons. Here, we further investigated the role of the subcellular localization of cyclin D1 in cell cycle withdrawal during the differentiation of N1E-115 neuroblastoma cells. We show that cyclin D1 became predominantly cytoplasmic after differentiation. Targeting cyclin D1 expression to the nucleus induced phosphorylation of Rb and cdk2 kinase activity. Furthermore, cyclin D1 nuclear localization promoted differentiated N1E-115 cells to reenter the cell cycle, amore » process that was inhibited by p16{sup INK4a}, a specific inhibitor of D-type cyclin activity. These results indicate that cytoplasmic sequestration of cyclin D1 plays a role in neuronal cell cycle withdrawal, and suggests that the abrogation of machinery involved in monitoring aberrant nuclear cyclin D1 activity contributes to neuronal tumorigenesis.« less

Cytoplasmic sequestration of cyclin D1 associated with cell cycle withdrawal of neuroblastoma cells.

PubMed

Sumrejkanchanakij, Piyamas; Eto, Kazuhiro; Ikeda, Masa-Aki

2006-02-03

The regulation of D-type cyclin-dependent kinase activity is critical for neuronal differentiation and apoptosis. We recently showed that cyclin D1 is sequestered in the cytoplasm and that its nuclear localization induces apoptosis in postmitotic primary neurons. Here, we further investigated the role of the subcellular localization of cyclin D1 in cell cycle withdrawal during the differentiation of N1E-115 neuroblastoma cells. We show that cyclin D1 became predominantly cytoplasmic after differentiation. Targeting cyclin D1 expression to the nucleus induced phosphorylation of Rb and cdk2 kinase activity. Furthermore, cyclin D1 nuclear localization promoted differentiated N1E-115 cells to reenter the cell cycle, a process that was inhibited by p16(INK4a), a specific inhibitor of D-type cyclin activity. These results indicate that cytoplasmic sequestration of cyclin D1 plays a role in neuronal cell cycle withdrawal, and suggests that the abrogation of machinery involved in monitoring aberrant nuclear cyclin D1 activity contributes to neuronal tumorigenesis.

Rootcap structure in wild type and in a starchless mutant of Arabidopsis

NASA Technical Reports Server (NTRS)

Sack, F. D.; Kiss, J. Z.

1989-01-01

Rootcaps of the wild type (WT) and of a starchless, gravitropic mutant (TC7) of Arabidopsis thaliana L. were examined by electron microscopy to identify cellular polarities with respect to gravity. In columella cells, nuclei are located proximally, and the nuclear envelope is continuous with endoplasmic reticulum (ER) that is in turn connected to nearby plasmodesmata. Impregnation of ER with osmium ferricyanide revealed numerous contacts between columella plastids and ER in both genotypes. ER is present mostly in the outer regions of the columella protoplast except in older columella cells that are developing into peripheral cells. In vertical roots, only columella cells that are intermediate in development (story 2 cells) have a higher surface density (S) of ER in the distal compared to proximal regions of the cell. The distal but not the proximal S of the ER is constant throughout columella development. Plastids are less sedimented in TC7 columella cells compared to those of the WT. It is hypothesized that plastid contact with the ER plays a role in gravity perception in both genotypes.

Characterization of an immortalized human vaginal epithelial cell line.

PubMed

Rajan, N; Pruden, D L; Kaznari, H; Cao, Q; Anderson, B E; Duncan, J L; Schaeffer, A J

2000-02-01

Adherence of type 1 piliated Escherichia coli to vaginal mucosa plays a major role in the pathogenesis of ascending urinary tract infections (UTIs) in women. Progress in understanding the mechanism of adherence to the vaginal surface could be enhanced by the utilization of well-characterized vaginal epithelial cells. The objective of this study was to immortalize vaginal epithelial cells and study their bacterial adherence properties. Primary vaginal cells were obtained from a normal post-menopausal woman, immortalized by infection with E6/E7 genes from human papillomavirus 16 (HPV 16) and cultured in serum free keratinocyte growth factor medium. Positive immunostaining with a pool of antibodies to cytokeratins 1, 5, 10 and 14 (K1, K5, K10 and K14) and to K13 confirmed the epithelial origin of these cells. The immortalized cells showed binding of type 1 piliated E. coli in a pili specific and mannose sensitive manner. This model system should facilitate studies on the interaction of pathogens with vaginal mucosal cells, an essential step in the progression of ascending UTIs in women.

gga-miR-155 Enhances Type I Interferon Expression and Suppresses Infectious Burse Disease Virus Replication via Targeting SOCS1 and TANK

PubMed Central

Wang, Bin; Fu, Mengjiao; Liu, Yanan; Wang, Yongqiang; Li, Xiaoqi; Cao, Hong; Zheng, Shijun J.

2018-01-01

Infectious bursal disease (IBD) is an acute, highly contagious, and immunosuppressive avian disease caused by IBD virus (IBDV). MicroRNAs (miRNAs) are involved in host-pathogen interactions and innate immune response to viral infection. However, the role of miRNAs in host response to IBDV infection is not clear. We report here that gga-miR-155 acts as an anti-virus host factor inhibiting IBDV replication. We found that transfection of DF-1 cells with gga-miR-155 suppressed IBDV replication, while blockage of the endogenous gga-miR-155 by inhibitors enhanced IBDV replication. Furthermore, our data showed that gga-miR-155 enhanced the expression of type I interferon in DF-1 cells post IBDV infection. Importantly, we found that gga-miR-155 enhanced type I interferon expression via targeting SOCS1 and TANK, two negative regulators of type I IFN signaling. These results indicate that gga-miR-155 plays a critical role in cell response to IBDV infection. PMID:29564226

α-Synuclein binds the KATP channel at insulin-secretory granules and inhibits insulin secretion

PubMed Central

Geng, Xuehui; Lou, Haiyan; Wang, Jian; Li, Lehong; Swanson, Alexandra L.; Sun, Ming; Beers-Stolz, Donna; Watkins, Simon; Perez, Ruth G.

2011-01-01

α-Synuclein has been studied in numerous cell types often associated with secretory processes. In pancreatic β-cells, α-synuclein might therefore play a similar role by interacting with organelles involved in insulin secretion. We tested for α-synuclein localizing to insulin-secretory granules and characterized its role in glucose-stimulated insulin secretion. Immunohistochemistry and fluorescent sulfonylureas were used to test for α-synuclein localization to insulin granules in β-cells, immunoprecipitation with Western blot analysis for interaction between α-synuclein and KATP channels, and ELISA assays for the effect of altering α-synuclein expression up or down on insulin secretion in INS1 cells or mouse islets, respectively. Differences in cellular phenotype between α-synuclein knockout and wild-type β-cells were found by using confocal microscopy to image the fluorescent insulin biosensor Ins-C-emGFP and by using transmission electron microscopy. The results show that anti-α-synuclein antibodies labeled secretory organelles within β-cells. Anti-α-synuclein antibodies colocalized with KATP channel, anti-insulin, and anti-C-peptide antibodies. α-Synuclein coimmunoprecipitated in complexes with KATP channels. Expression of α-synuclein downregulated insulin secretion at 2.8 mM glucose with little effect following 16.7 mM glucose stimulation. α-Synuclein knockout islets upregulated insulin secretion at 2.8 and 8.4 mM but not 16.7 mM glucose, consistent with the depleted insulin granule density at the β-cell surface membranes observed in these islets. These findings demonstrate that α-synuclein interacts with KATP channels and insulin-secretory granules and functionally acts as a brake on secretion that glucose stimulation can override. α-Synuclein might play similar roles in diabetes as it does in other degenerative diseases, including Alzheimer's and Parkinson's diseases. PMID:20858756

Tripeptidyl peptidase II plays a role in the radiation response of selected primary cell types but not based on nuclear translocation and p53 stabilization.

PubMed

Firat, Elke; Tsurumi, Chizuko; Gaedicke, Simone; Huai, Jisen; Niedermann, Gabriele

2009-04-15

The giant cytosolic protease tripeptidyl peptidase II (TPPII) was recently proposed to play a role in the DNA damage response. Shown were nuclear translocation of TPPII after gamma-irradiation, lack of radiation-induced p53 stabilization in TPPII-siRNA-treated cells, and complete tumor regression in mice after gamma-irradiation when combined with TPPII-siRNA silencing or a protease inhibitor reported to inhibit TPPII. This suggested that TPPII could be a novel target for tumor radiosensitization and prompted us to study radiation responses using TPPII-knockout mice. Neither the sensitivity to total body irradiation nor the radiosensitivity of resting lymphoid cells, which both strongly depend on p53, was altered in the absence of TPPII. Functional integrity of p53 in TPPII-knockout cells is further shown by a proper G(1) arrest and by the accumulation of p53 and its transcriptional targets, p21, Bax, and Fas, on gamma-irradiation. Furthermore, we could not confirm radiation-induced nuclear translocation of TPPII. Nevertheless, after gamma-irradiation, we found slightly increased mitotic catastrophe of TPPII-deficient primary fibroblasts and increased apoptosis of TPPII-deficient activated CD8(+) T cells. The latter was accompanied by delayed resolution of the DNA double-strand break marker gammaH2AX. This could, however, be due to increased apoptotic DNA damage rather than reduced DNA damage repair. Our data do not confirm a role for TPPII in the DNA damage response based on nuclear TPPII translocation and p53 stabilization but nevertheless do show increased radiation-induced cell death of selected nontransformed cell types in the absence of the TPPII protease.

Contributions of diverse excitatory and inhibitory neurons to recurrent network activity in cerebral cortex.

PubMed

Neske, Garrett T; Patrick, Saundra L; Connors, Barry W

2015-01-21

The recurrent synaptic architecture of neocortex allows for self-generated network activity. One form of such activity is the Up state, in which neurons transiently receive barrages of excitatory and inhibitory synaptic inputs that depolarize many neurons to spike threshold before returning to a relatively quiescent Down state. The extent to which different cell types participate in Up states is still unclear. Inhibitory interneurons have particularly diverse intrinsic properties and synaptic connections with the local network, suggesting that different interneurons might play different roles in activated network states. We have studied the firing, subthreshold behavior, and synaptic conductances of identified cell types during Up and Down states in layers 5 and 2/3 in mouse barrel cortex in vitro. We recorded from pyramidal cells and interneurons expressing parvalbumin (PV), somatostatin (SOM), vasoactive intestinal peptide (VIP), or neuropeptide Y. PV cells were the most active interneuron subtype during the Up state, yet the other subtypes also received substantial synaptic conductances and often generated spikes. In all cell types except PV cells, the beginning of the Up state was dominated by synaptic inhibition, which decreased thereafter; excitation was more persistent, suggesting that inhibition is not the dominant force in terminating Up states. Compared with barrel cortex, SOM and VIP cells were much less active in entorhinal cortex during Up states. Our results provide a measure of functional connectivity of various neuron types in barrel cortex and suggest differential roles for interneuron types in the generation and control of persistent network activity. Copyright © 2015 the authors 0270-6474/15/351089-17$15.00/0.

Circuits that Innervate Excitatory-Inhibitory Cells in the Inferior Colliculus Obtained with In-Vivo Whole Cell Recordings

PubMed Central

Li, Na; Pollak, George D.

2013-01-01

Neurons excited by stimulation of one ear and suppressed by the other, called EI neurons, are sensitive to interaural intensity disparities (IIDs), the cues animals use to localize high frequencies. EI neurons are first formed in lateral superior olive (LSO), which then sends excitatory projections to the dorsal nucleus of the lateral lemniscus (DNLL) and the inferior colliculus (IC), both of which contain large populations of EI cells. We evaluate the inputs that innervate EI cells in the IC of Mexican free-tailed bats, Tadarida brasilensis mexicana, with in vivo whole cell recordings from which we derived excitatory and inhibitory conductances. We show that the basic EI property in the majority of IC cells is inherited from LSO, but each type of EI cell is also innervated by the ipsi- or contralateral DNLL, as well as additional excitatory and inhibitory inputs from monaural nuclei. We identify three EI types, where each type receives a set of projections that are different from the other types. To evaluate the role that the various projections played in generating binaural responses, we used modeling to compute a predicted response from the conductances. We then omitted one of the conductances from the computation to evaluate the degree to which that input contributed to the binaural response. We show that formation of the EI property in the various types is complex, and that some projections exert such subtle influences that they could not have been detected with extracellular recordings or even from intracellular recordings of post-synaptic potentials. PMID:23575835

Meeting and Serving Users in Their New Work (and Play) Spaces

ERIC Educational Resources Information Center

Peters, Tom

2008-01-01

This article examines the public services component of digital and virtual libraries, focusing on the end-user experience. As the number and types of "places" where library users access library collections and services continue to expand (now including cell phones, iPods, and three-dimensional virtual reality environments populated by avatars),…

Take the Science Fair Online!

ERIC Educational Resources Information Center

Tubbs, James

2007-01-01

The kids in today's classrooms spend lots of time playing video games, surfing the net, listening to iPods, and text messaging on cell phones. Known as Digital Kids and the Net Generation, they have grown up surrounded by digital media of all types (Tapscott 1999). Because they are already knowledgeable, why not use digital technologies to capture…

Group X Phospholipase A2 Stimulates the Proliferation of Colon Cancer Cells by Producing Various Lipid Mediators

PubMed Central

Surrel, Fanny; Jemel, Ikram; Boilard, Eric; Bollinger, James G.; Payré, Christine; Mounier, Carine M.; Talvinen, Kati A.; Laine, Veli J. O.; Nevalainen, Timo J.; Gelb, Michael H.

2009-01-01

Among mammalian secreted phospholipases A2 (sPLA2s), the group X enzyme has the most potent hydrolyzing capacity toward phosphatidylcholine, the major phospholipid of cell membrane and lipoproteins. This enzyme has recently been implicated in chronic inflammatory diseases such as atherosclerosis and asthma and may also play a role in colon tumorigenesis. We show here that group X sPLA2 [mouse (m)GX] is one of the most highly expressed PLA2 in the mouse colon and that recombinant mouse and human enzymes stimulate proliferation and mitogen-activated protein kinase activation of various colon cell lines, including Colon-26 cancer cells. Among various recombinant sPLA2s, mGX is the most potent enzyme to stimulate cell proliferation. Based on the use of sPLA2 inhibitors, catalytic site mutants, and small interfering RNA silencing of cytosolic PLA2α and M-type sPLA2 receptor, we demonstrate that mGX promotes cell proliferation independently of the receptor and via its intrinsic catalytic activity and production of free arachidonic acid and lysophospholipids, which are mitogenic by themselves. mGX can also elicit the production of large amounts of prostaglandin E2 and other eicosanoids from Colon-26 cells, but these lipid mediators do not play a role in mGX-induced cell proliferation because inhibitors of cyclooxygenases and lipoxygenases do not prevent sPLA2 mitogenic effects. Together, our results indicate that group X sPLA2 may play an important role in colon tumorigenesis by promoting cancer cell proliferation and releasing various lipid mediators involved in other key events in cancer progression. PMID:19602573

Group X phospholipase A2 stimulates the proliferation of colon cancer cells by producing various lipid mediators.

PubMed

Surrel, Fanny; Jemel, Ikram; Boilard, Eric; Bollinger, James G; Payré, Christine; Mounier, Carine M; Talvinen, Kati A; Laine, Veli J O; Nevalainen, Timo J; Gelb, Michael H; Lambeau, Gérard

2009-10-01

Among mammalian secreted phospholipases A2 (sPLA(2)s), the group X enzyme has the most potent hydrolyzing capacity toward phosphatidylcholine, the major phospholipid of cell membrane and lipoproteins. This enzyme has recently been implicated in chronic inflammatory diseases such as atherosclerosis and asthma and may also play a role in colon tumorigenesis. We show here that group X sPLA(2) [mouse (m)GX] is one of the most highly expressed PLA(2) in the mouse colon and that recombinant mouse and human enzymes stimulate proliferation and mitogen-activated protein kinase activation of various colon cell lines, including Colon-26 cancer cells. Among various recombinant sPLA(2)s, mGX is the most potent enzyme to stimulate cell proliferation. Based on the use of sPLA(2) inhibitors, catalytic site mutants, and small interfering RNA silencing of cytosolic PLA(2)alpha and M-type sPLA(2) receptor, we demonstrate that mGX promotes cell proliferation independently of the receptor and via its intrinsic catalytic activity and production of free arachidonic acid and lysophospholipids, which are mitogenic by themselves. mGX can also elicit the production of large amounts of prostaglandin E2 and other eicosanoids from Colon-26 cells, but these lipid mediators do not play a role in mGX-induced cell proliferation because inhibitors of cyclooxygenases and lipoxygenases do not prevent sPLA(2) mitogenic effects. Together, our results indicate that group X sPLA(2) may play an important role in colon tumorigenesis by promoting cancer cell proliferation and releasing various lipid mediators involved in other key events in cancer progression.

Dual Innervation of Neonatal Merkel Cells in Mouse Touch Domes

PubMed Central

Luo, Wenqin

2014-01-01

Merkel cell-neurite complexes are specialized mechanosensory end organs that mediate discriminative touch sensation. It is well established that type I slowly adapting (SAI) mechanoreceptors, which express neural filament heavy chain (NFH), innervate Merkel cells. It was previously shown that neurotrophic factor NT3 and its receptor TrkC play crucial roles in controlling touch dome Merkel cell innervation of NFH+ fibers. In addition, nerve fibers expressing another neurotrophic tyrosine receptor kinase (NTRK), Ret, innervate touch dome Merkel cells as well. However, the relationship between afferents responsive to NT3/TrkC signaling and those expressing Ret is unclear. It is also controversial if these Ret+ fibers belong to the early or late Ret+ DRG neurons, which are defined based on the co-expression and developmental dependence of TrkA. To address these questions, we genetically traced Ret+ and TrkC+ fibers and analyzed their developmental dependence on TrkA. We found that Merkel cells in neonatal mouse touch domes receive innervation of two types of fibers: one group is Ret+, while the other subset expresses TrkC and NFH. In addition, Ret+ fibers depend on TrkA for their survival and normal innervation whereas NFH+ Merkel cell innervating fibers are almost unaltered in TrkA mutant mice, supporting that Ret+ and NFH+/TrkC+ afferents are two distinct groups. Ret signaling, on the other hand, plays a minor role for the innervation of neonatal touch domes. In contrast, Merkel cells in the glabrous skin are mainly contacted by NFH+/TrkC+ afferents. Taken together, our results suggest that neonatal Merkel cells around hair follicles receive dual innervation while Merkel cells in the glabrous skin are mainly innervated by only SAI mechanoreceptors. In addition, our results suggest that neonatal Ret+ Merkel cell innervating fibers most likely belong to the late but not early Ret+ DRG neurons. PMID:24637732

Parsimony and complexity: Cell fate assignment in the developing Drosophila eye.

PubMed

Mavromatakis, Yannis Emmanuel; Tomlinson, Andrew

2017-07-03

The specification of the R7 photoreceptor in the Drosophila eye has become a classic model for understanding how cell fates are assigned in developing systems. R7 is derived from a group of cells that also gives rise to the R1/6 photoreceptor class and the non-photoreceptor cone cells. Our studies examine the signals and cellular information that direct each of these cell types. The cell fates are directed by the combined actions of the Receptor Tyrosine Kinase (RTK) and Notch (N) signaling pathways. The RTK pathway acts to remove the transcription factor Tramtrack (Ttk) which represses the photoreceptor fate. If a cell receives an RTK signal sufficient to remove Ttk then the photoreceptor fate is specified; if not, the cone cell fate results. If Ttk is removed from a cell and its N activity is high then it is specified as an R7, but if its N activity is low then it becomes an R1/6 class photoreceptor. Thus, a remarkably simple molecular code underlies the specification of the fates: 1. Ttk degraded or not: 2. N activity high or low. In the R1/6 and cone cell precursors the molecular codes are achieved with relative simplicity but in the R7 precursor, manifold interactions occur between the RTK and N pathways, and to-date we have identified 4 distinct roles played by N in R7 fate specification. In this review we detail this molecular complexity, and describe how the RTK/N pathway crosstalk eventually leads to the simple molecular code of Tramtrack removed and N activity high. Furthermore, we describe the role played by the transcription factor Lozenge (Lz) in directing retinal precursor fates, and how the RTK/N signals specify different retinal cell types depending on the presence or absence of Lz.

A Bacterial Pathogen Displaying Temperature-Enhanced Virulence of the Microalga Emiliania huxleyi

PubMed Central

Mayers, Teaghan J.; Bramucci, Anna R.; Yakimovich, Kurt M.; Case, Rebecca J.

2016-01-01

Emiliania huxleyi is a globally abundant microalga that plays a significant role in biogeochemical cycles. Over the next century, sea surface temperatures are predicted to increase drastically, which will likely have significant effects on the survival and ecology of E. huxleyi. In a warming ocean, this microalga may become increasingly vulnerable to pathogens, particularly those with temperature-dependent virulence. Ruegeria is a genus of Rhodobacteraceae whose population size tracks that of E. huxleyi throughout the alga’s bloom–bust lifecycle. A representative of this genus, Ruegeria sp. R11, is known to cause bleaching disease in a red macroalga at elevated temperatures. To investigate if the pathogenicity of R11 extends to microalgae, it was co-cultured with several cell types of E. huxleyi near the alga’s optimum (18°C), and at an elevated temperature (25°C) known to induce virulence in R11. The algal populations were monitored using flow cytometry and pulse-amplitude modulated fluorometry. Cultures of algae without bacteria remained healthy at 18°C, but lower cell counts in control cultures at 25°C indicated some stress at the elevated temperature. Both the C (coccolith-bearing) and S (scale-bearing swarming) cell types of E. huxleyi experienced a rapid decline resulting in apparent death when co-cultured with R11 at 25°C, but had no effect on N (naked) cell type at either temperature. R11 had no initial negative impact on C and S type E. huxleyi population size or health at 18°C, but caused death in older co-cultures. This differential effect of R11 on its host at 18 and 25°C suggest it is a temperature-enhanced opportunistic pathogen of E. huxleyi. We also detected caspase-like activity in dying C type cells co-cultured with R11, which suggests that programmed cell death plays a role in the death of E. huxleyi triggered by R11 – a mechanism induced by viruses (EhVs) and implicated in E. huxleyi bloom collapse. Given that E. huxleyi has recently been shown to have acquired resistance against EhVs at elevated temperature, bacterial pathogens with temperature-dependent virulence, such as R11, may become much more important in the ecology of E. huxleyi in a warming climate. PMID:27379036

A Bacterial Pathogen Displaying Temperature-Enhanced Virulence of the Microalga Emiliania huxleyi.

PubMed

Mayers, Teaghan J; Bramucci, Anna R; Yakimovich, Kurt M; Case, Rebecca J

2016-01-01

Emiliania huxleyi is a globally abundant microalga that plays a significant role in biogeochemical cycles. Over the next century, sea surface temperatures are predicted to increase drastically, which will likely have significant effects on the survival and ecology of E. huxleyi. In a warming ocean, this microalga may become increasingly vulnerable to pathogens, particularly those with temperature-dependent virulence. Ruegeria is a genus of Rhodobacteraceae whose population size tracks that of E. huxleyi throughout the alga's bloom-bust lifecycle. A representative of this genus, Ruegeria sp. R11, is known to cause bleaching disease in a red macroalga at elevated temperatures. To investigate if the pathogenicity of R11 extends to microalgae, it was co-cultured with several cell types of E. huxleyi near the alga's optimum (18°C), and at an elevated temperature (25°C) known to induce virulence in R11. The algal populations were monitored using flow cytometry and pulse-amplitude modulated fluorometry. Cultures of algae without bacteria remained healthy at 18°C, but lower cell counts in control cultures at 25°C indicated some stress at the elevated temperature. Both the C (coccolith-bearing) and S (scale-bearing swarming) cell types of E. huxleyi experienced a rapid decline resulting in apparent death when co-cultured with R11 at 25°C, but had no effect on N (naked) cell type at either temperature. R11 had no initial negative impact on C and S type E. huxleyi population size or health at 18°C, but caused death in older co-cultures. This differential effect of R11 on its host at 18 and 25°C suggest it is a temperature-enhanced opportunistic pathogen of E. huxleyi. We also detected caspase-like activity in dying C type cells co-cultured with R11, which suggests that programmed cell death plays a role in the death of E. huxleyi triggered by R11 - a mechanism induced by viruses (EhVs) and implicated in E. huxleyi bloom collapse. Given that E. huxleyi has recently been shown to have acquired resistance against EhVs at elevated temperature, bacterial pathogens with temperature-dependent virulence, such as R11, may become much more important in the ecology of E. huxleyi in a warming climate.

The role of KATP channels in cerebral ischemic stroke and diabetes

PubMed Central

Szeto, Vivian; Chen, Nai-hong; Sun, Hong-shuo; Feng, Zhong-ping

2018-01-01

ATP-sensitive potassium (KATP) channels are ubiquitously expressed on the plasma membrane of cells in multiple organs, including the heart, pancreas and brain. KATP channels play important roles in controlling and regulating cellular functions in response to metabolic state, which are inhibited by ATP and activated by Mg-ADP, allowing the cell to couple cellular metabolic state (ATP/ADP ratio) to electrical activity of the cell membrane. KATP channels mediate insulin secretion in pancreatic islet beta cells, and controlling vascular tone. Under pathophysiological conditions, KATP channels play cytoprotective role in cardiac myocytes and neurons during ischemia and/or hypoxia. KATP channel is a hetero-octameric complex, consisting of four pore-forming Kir6.x and four regulatory sulfonylurea receptor SURx subunits. These subunits are differentially expressed in various cell types, thus determining the sensitivity of the cells to specific channel modifiers. Sulfonylurea class of antidiabetic drugs blocks KATP channels, which are neuroprotective in stroke, can be one of the high stoke risk factors for diabetic patients. In this review, we discussed the potential effects of KATP channel blockers when used under pathological conditions related to diabetics and cerebral ischemic stroke. PMID:29671418

Aquaporin-4 immunoreactivity in Müller and amacrine cells of marine teleost fish retina.

PubMed

Hombrebueno, José R; Lee, Eun-Jin; Martínez-Ruiz, Noemí; García-Alcázar, Alicia; Grzywacz, Norberto M; De Juan, Joaquín

2012-01-13

Aquaporins (AQPs) are membrane proteins that facilitate water transport across biological membranes and are essential for the proper function of neural tissue. Although AQPs have been extensively studied in mammalian retina, their presence in lower vertebrate retina is less frequently characterized. AQP4 expressed in mammalian and chick Müller cells plays a major part in maintaining retinal homeostasis. In this study, we examined the immunoreactivity of AQP4 in the adult retina of gilthead sea bream (Sparus aurata-teleost fish), during light and dark adaptation. The AQP4 expression was detected in Müller cell somas at the inner nuclear layer and in the end-feet processes near the vitreoretinal border. Moreover, AQP4 was also evident in cone photoreceptor cells and in a GABAergic subpopulation of amacrine cells (AQP4-ACs). Four different types of AQP4-ACs were characterized based on their morphology and dendrite stratification. Interestingly, a stronger AQP4 immunoreactivity was observed in the inner nuclear layer during dark adaptation, accompanied by a significant increment in AQP4-ACs cell size. Hence, AQP4 may play an important role in water distribution in the teleost fish retina. Copyright © 2011 Elsevier B.V. All rights reserved.

IL-33: biological properties, functions, and roles in airway disease.

PubMed

Drake, Li Yin; Kita, Hirohito

2017-07-01

Interleukin (IL)-33 is a key cytokine involved in type 2 immunity and allergic airway diseases. Abundantly expressed in lung epithelial cells, IL-33 plays critical roles in both innate and adaptive immune responses in mucosal organs. In innate immunity, IL-33 and group 2 innate lymphoid cells (ILC2s) provide an essential axis for rapid immune responses and tissue homeostasis. In adaptive immunity, IL-33 interacts with dendritic cells, Th2 cells, follicular T cells, and regulatory T cells, where IL-33 influences the development of chronic airway inflammation and tissue remodeling. The clinical findings that both the IL-33 and ILC2 levels are elevated in patients with allergic airway diseases suggest that IL-33 plays an important role in the pathogenesis of these diseases. IL-33 and ILC2 may also serve as biomarkers for disease classification and to monitor the progression of diseases. In this article, we reviewed the current knowledge of the biology of IL-33 and discussed the roles of the IL-33 in regulating airway immune responses and allergic airway diseases. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Left atrial appendages from adult hearts contain a reservoir of diverse cardiac progenitor cells.

PubMed

Leinonen, Jussi V; Emanuelov, Avishag K; Platt, Yardanna; Helman, Yaron; Feinberg, Yael; Lotan, Chaim; Beeri, Ronen

2013-01-01

There is strong evidence supporting the claim that endogenous cardiac progenitor cells (CPCs) are key players in cardiac regeneration, but the anatomic source and phenotype of the master cardiac progenitors remains uncertain. Our aim was to investigate the different cardiac stem cell populations in the left atrial appendage (LAA) and their fates. We investigated the CPC content and profile of adult murine LAAs using immunohistochemistry and flow cytometry. We demonstrate that the LAA contains a large number of CPCs relative to other areas of the heart, representing over 20% of the total cell number. We grew two distinct CPC populations from the LAA by varying the degree of proteolysis. These differed by their histological location, surface marker profiles and growth dynamics. Specifically, CD45(pos) cells grew with milder proteolysis, while CD45(neg) cells grew mainly with more intense proteolysis. Both cell types could be induced to differentiate into cells with cardiomyocyte markers and organelles, albeit by different protocols. Many CD45(pos) cells expressed CD45 initially and rapidly lost its expression while differentiating. Our results demonstrate that the left atrial appendage plays a role as a reservoir of multiple types of progenitor cells in murine adult hearts. Two different types of CPCs were isolated, differing in their epicardial-myocardial localization. Considering studies demonstrating layer-specific origins of different cardiac progenitor cells, our findings may shed light on possible pathways to study and utilize the diversity of endogenous progenitor cells in the adult heart.

Remodeling of bovine oviductal epithelium by mitosis of secretory cells.

PubMed

Ito, Sayaka; Kobayashi, Yoshihiko; Yamamoto, Yuki; Kimura, Koji; Okuda, Kiyoshi

2016-11-01

Two types of oviductal epithelial cells, secretory and ciliated, play crucial roles in the first days after fertilization in mammals. Secretory cells produce various molecules promoting embryo development, while ciliated cells facilitate transport of oocytes and zygotes by ciliary beating. The proportions of the two cell types change during the estrous cycle. The proportion of ciliated cells on the oviductal luminal surface is abundant at the follicular phase, whereas the proportion of secretory cells gradually increases with the formation of the corpus luteum. In the present study, we hypothesize that the proportions of ciliated and secretory epithelial cells are regulated by mitosis. The proportion of the cells being positive for FOXJ1 (a ciliated cell marker) or Ki67 (a mitosis marker) in epithelial cells during the estrous cycle were immunohistochemically examined. Ki67 and FOXJ1 or PAX8 (a secretory cell marker), were double-stained to clarify which types of epithelial cells undergo mitosis. In the ampulla, the percentage of FOXJ1-positive cells was highest at the day of ovulation (Day 0) and decreased by about 50 % by Days 8-12, while in the isthmus it did not change during the estrous cycle. The proportion of Ki67-positive cells was highest at around the time of ovulation in both the ampulla and isthmus. All the Ki67-positive cells were PAX8-positive and FOXJ1-negative in both the ampulla and isthmus. These findings suggest that epithelial remodeling, which is regulated by differentiation and/or proliferation of secretory cells of the oviduct, provides the optimal environment for gamete transport, fertilization and embryonic development.

The dlt genes play a role in antimicrobial tolerance of Streptococcus mutans biofilms.

PubMed

Nilsson, Martin; Rybtke, Morten; Givskov, Michael; Høiby, Niels; Twetman, Svante; Tolker-Nielsen, Tim

2016-09-01

Microbial biofilms are tolerant to antibiotic treatment and therefore cause problematic infections. Knowledge about the molecular mechanisms underlying biofilm-associated antimicrobial tolerance will aid the development of antibiofilm drugs. Screening of a Streptococcus mutans transposon mutant library for genes that are important for biofilm-associated antimicrobial tolerance provided evidence that the dlt genes play a role in the tolerance of S. mutans biofilms towards gentamicin. The minimum bactericidal concentration for biofilm cells (MBC-B) for a dltA transposon mutant was eight-fold lower than that of the wild-type. The minimum bactericidal concentration for planktonic cells (MBC-P) was only slightly reduced, indicating that the mechanism involved in the observed antimicrobial tolerance has a predominant role specifically in biofilms. Experiments with a knockout dltA mutant and complemented strain confirmed that the dlt genes in S. mutans play a role in biofilm-associated tolerance to gentamicin. Confocal laser scanning microscopy analyses of biofilms grown on glass slides showed that the dltA mutant produced roughly the same amount of biofilm as the wild-type, indicating that the reduced antimicrobial tolerance of the dltA mutant is not due to a defect in biofilm formation. The products of the dlt genes have been shown to mediate alanylation of teichoic acids, and in accordance the dltA mutant showed a more negatively charged surface than the wild-type, which likely is an important factor in the reduced tolerance of the dltA mutant biofilms towards the positively charged gentamicin. Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

Targeted deletion and lipidomic analysis identify epithelial cell COX-2 as a major driver of chemically induced skin cancer.

PubMed

Jiao, Jing; Ishikawa, Tomo-O; Dumlao, Darren S; Norris, Paul C; Magyar, Clara E; Mikulec, Carol; Catapang, Art; Dennis, Edward A; Fischer, Susan M; Herschman, Harvey R

2014-11-01

Pharmacologic and global gene deletion studies demonstrate that cyclooxygenase-2 (PTGS2/COX-2) plays a critical role in DMBA/TPA-induced skin tumor induction. Although many cell types in the tumor microenvironment express COX-2, the cell types in which COX-2 expression is required for tumor promotion are not clearly established. Here, cell type-specific Cox-2 gene deletion reveals a vital role for skin epithelial cell COX-2 expression in DMBA/TPA tumor induction. In contrast, myeloid Cox-2 gene deletion has no effect on DMBA/TPA tumorigenesis. The infrequent, small tumors that develop on mice with an epithelial cell-specific Cox-2 gene deletion have decreased proliferation and increased cell differentiation properties. Blood vessel density is reduced in tumors with an epithelial cell-specific Cox-2 gene deletion, compared with littermate control tumors, suggesting a reciprocal relationship in tumor progression between COX-2-expressing tumor epithelial cells and microenvironment endothelial cells. Lipidomics analysis of skin and tumors from DMBA/TPA-treated mice suggests that the prostaglandins PGE2 and PGF2α are likely candidates for the epithelial cell COX-2-dependent eicosanoids that mediate tumor progression. This study both illustrates the value of cell type-specific gene deletions in understanding the cellular roles of signal-generating pathways in complex microenvironments and emphasizes the benefit of a systems-based lipidomic analysis approach to identify candidate lipid mediators of biologic responses. Cox-2 gene deletion demonstrates that intrinsic COX-2 expression in initiated keratinocytes is a principal driver of skin carcinogenesis; lipidomic analysis identifies likely prostanoid effectors. ©2014 American Association for Cancer Research.

Anti-differentiation non-coding RNA, ANCR, is differentially expressed in different types of brain tumors.

PubMed

Malakootian, Mahshid; Mirzadeh Azad, Fatemeh; Fouani, Youssef; Taheri Bajgan, Elham; Saberi, Hooshang; Mowla, Seyed Javad

2018-06-01

Long non-coding RNAs (lncRNAs) are important modulators of various cellular and molecular events, including cancer-associated pathways. The Anti-differentiation ncRNA (ANCR) is a key regulator of keratinocyte differentiation, where its expression is necessary to maintain epidermal progenitor's cells. Herein, we investigated the expression pattern of ANCR in the course of neural differentiation. Moreover, we used published RNAseq data and clinical samples to evaluate the alteration of ANCR expression in different cell types and brain tumors. Furthermore, we manipulated ANCR expression in glioma cell lines to clarify a potential functional role for ANCR in tumorigenesis. Our qRT-PCR results revealed a significant upregulation of ANCR in more malignant and less differentiated types of brain tumors (P = 0.03). This data was in accordance with down regulation of ANCR during neural differentiation. ANCR suppression caused an elevation in apoptosis rate, as well as a G1 cell cycle arrest in glioblastoma cell line. Altogether, our data demonstrated that ANCR may play a role in glioma genesis and that it could be considered as a potential diagnostic and therapeutic target to combat brain cancers.

Reduction of Circulating Neutrophils Precedes and Accompanies Type 1 Diabetes

PubMed Central

Valle, Andrea; Giamporcaro, Gian Maria; Scavini, Marina; Stabilini, Angela; Grogan, Pauline; Bianconi, Eleonora; Sebastiani, Guido; Masini, Matilde; Maugeri, Norma; Porretti, Laura; Bonfanti, Riccardo; Meschi, Franco; De Pellegrin, Maurizio; Lesma, Arianna; Rossini, Silvano; Piemonti, Lorenzo; Marchetti, Piero; Dotta, Francesco; Bosi, Emanuele; Battaglia, Manuela

2013-01-01

Human type 1 diabetes (T1D) is an autoimmune disease associated with major histocompatibility complex polymorphisms, β-cell autoantibodies, and autoreactive T cells. However, there is increasing evidence that innate cells may also play critical roles in T1D. We aimed to monitor peripheral immune cells in early stages of T1D (i.e., in healthy autoantibody-positive subjects) and in more advanced phases of the disease (i.e., at disease onset and years after diagnosis). We found a mild but significant and reproducible peripheral neutropenia that both precedes and accompanies the onset of T1D. This reduction was not due to peripheral neutrophil cell death, impaired differentiation, or the presence of anti-neutrophil antibodies. Neutrophils were observed by electron microscopy and immunohistochemical analysis in the exocrine pancreas of multiorgan donors with T1D (both at onset and at later stages of the disease) and not in that of multiorgan donors with type 2 diabetes or nondiabetic donors. These pancreas-infiltrating neutrophils mainly localized at the level of very small blood vessels. Our findings suggest the existence of a hitherto unrecognized clinical phenotype that might reflect unexplored pathogenic pathways underlying T1D. PMID:23349491

FOG-2, a Heart- and Brain-Enriched Cofactor for GATA Transcription Factors

PubMed Central

Lu, Jian-rong; McKinsey, Timothy A.; Xu, Hongtao; Wang, Da-zhi; Richardson, James A.; Olson, Eric N.

1999-01-01

Members of the GATA family of zinc finger transcription factors have been shown to play important roles in the control of gene expression in a variety of cell types. GATA-1, -2, and -3 are expressed primarily in hematopoietic cell lineages and are required for proliferation and differentiation of multiple hematopoietic cell types, whereas GATA-4, -5, and -6 are expressed in the heart, where they activate cardiac muscle structural genes. Friend of GATA-1 (FOG) is a multitype zinc finger protein that interacts with GATA-1 and serves as a cofactor for GATA-1-mediated transcription. FOG is coexpressed with GATA-1 in developing erythroid and megakaryocyte cell lineages and cooperates with GATA-1 to control erythropoiesis. We describe a novel FOG-related factor, FOG-2, that is expressed predominantly in the developing and adult heart, brain, and testis. FOG-2 interacts with GATA factors, and interaction of GATA-4 and FOG-2 results in either synergistic activation or repression of GATA-dependent cardiac promoters, depending on the specific promoter and the cell type in which they are tested. The properties of FOG-2 suggest its involvement in the control of cardiac and neural gene expression by GATA transcription factors. PMID:10330188

Dynamic Reorganization of the Cytoskeleton during Apoptosis: The Two Coffins Hypothesis.

PubMed

Povea-Cabello, Suleva; Oropesa-Ávila, Manuel; de la Cruz-Ojeda, Patricia; Villanueva-Paz, Marina; de la Mata, Mario; Suárez-Rivero, Juan Miguel; Álvarez-Córdoba, Mónica; Villalón-García, Irene; Cotán, David; Ybot-González, Patricia; Sánchez-Alcázar, José A

2017-11-11

During apoptosis, cells undergo characteristic morphological changes in which the cytoskeleton plays an active role. The cytoskeleton rearrangements have been mainly attributed to actinomyosin ring contraction, while microtubule and intermediate filaments are depolymerized at early stages of apoptosis. However, recent results have shown that microtubules are reorganized during the execution phase of apoptosis forming an apoptotic microtubule network (AMN). Evidence suggests that AMN is required to maintain plasma membrane integrity and cell morphology during the execution phase of apoptosis. The new "two coffins" hypothesis proposes that both AMN and apoptotic cells can adopt two morphological patterns, round or irregular, which result from different cytoskeleton kinetic reorganization during the execution phase of apoptosis induced by genotoxic agents. In addition, round and irregular-shaped apoptosis showed different biological properties with respect to AMN maintenance, plasma membrane integrity and phagocyte responses. These findings suggest that knowing the type of apoptosis may be important to predict how fast apoptotic cells undergo secondary necrosis and the subsequent immune response. From a pathological point of view, round-shaped apoptosis can be seen as a physiological and controlled type of apoptosis, while irregular-shaped apoptosis can be considered as a pathological type of cell death closer to necrosis.

Dynamic Reorganization of the Cytoskeleton during Apoptosis: The Two Coffins Hypothesis

PubMed Central

Povea-Cabello, Suleva; Oropesa-Ávila, Manuel; de la Cruz-Ojeda, Patricia; Villanueva-Paz, Marina; de la Mata, Mario; Álvarez-Córdoba, Mónica; Villalón-García, Irene; Cotán, David; Ybot-González, Patricia

2017-01-01

During apoptosis, cells undergo characteristic morphological changes in which the cytoskeleton plays an active role. The cytoskeleton rearrangements have been mainly attributed to actinomyosin ring contraction, while microtubule and intermediate filaments are depolymerized at early stages of apoptosis. However, recent results have shown that microtubules are reorganized during the execution phase of apoptosis forming an apoptotic microtubule network (AMN). Evidence suggests that AMN is required to maintain plasma membrane integrity and cell morphology during the execution phase of apoptosis. The new “two coffins” hypothesis proposes that both AMN and apoptotic cells can adopt two morphological patterns, round or irregular, which result from different cytoskeleton kinetic reorganization during the execution phase of apoptosis induced by genotoxic agents. In addition, round and irregular-shaped apoptosis showed different biological properties with respect to AMN maintenance, plasma membrane integrity and phagocyte responses. These findings suggest that knowing the type of apoptosis may be important to predict how fast apoptotic cells undergo secondary necrosis and the subsequent immune response. From a pathological point of view, round-shaped apoptosis can be seen as a physiological and controlled type of apoptosis, while irregular-shaped apoptosis can be considered as a pathological type of cell death closer to necrosis. PMID:29137119

Ephs and Ephrins in Cancer: Ephrin-A1 Signaling

PubMed Central

Beauchamp, Amanda; Debinski, Waldemar

2011-01-01

Ephrin-A1 and its primary receptor, EphA2, are involved in numerous physiological processes and have been intensely studied for their roles in malignancy. Ephrin-Eph signalling is complex on its own and is also cell-type dependent, making elucidation of the exact role of ephrin-A1 in neoplasia challenging. Multiple oncogenic signalling pathways, such as MAP/ERK and PI3K are affected by ephrin-A1, and in some cases evidence suggests the promotion of a specific pathway in one cell or cancer type and inhibition of the same pathway in another type of cell or cancer. EphrinA1 also plays an integral role in angiogenesis and tumor neovascularization. Until recently, studies investigating ephrins focused on the ligands as GPI-anchored proteins that required membrane anchoring or artificial clustering for Eph receptor activation. However, recent studies have demonstrated a functional role for soluble, monomeric ephrin-A1. This review will focus on various forms of ephrin-A1-specific signalling in human malignancy. PMID:22040911

The MVMp P4 promoter is a host cell-type range determinant in vivo.

PubMed

Meir, Chen; Mincberg, Michal; Rostovsky, Irina; Tal, Saar; Vollmers, Ellen M; Levi, Adi; Tattersall, Peter; Davis, Claytus

2017-06-01

The protoparvovirus early promoters, e.g. P4 of Minute Virus of Mice (MVM), play a critical role during infection. Initial P4 activity depends on the host transcription machinery only. Since this is cell-type dependent, it is hypothesized that P4 is a host cell-type range determinant. Yet host range determinants have mapped mostly to capsid, never P4. Here we test the hypothesis using the mouse embryo as a model system. Disruption of the CRE element of P4 drastically decreased infection levels without altering range. However, when we swapped promoter elements of MVM P4 with those from equivalent regions of the closely related H1 virus, we observed elimination of infection in fibroblasts and chondrocytes and the acquisition of infection in skeletal muscle. We conclude that P4 is a host range determinant and a target for modifying the productive infection potential of the virus - an important consideration in adapting these viruses for oncotherapy. Copyright © 2017 Elsevier Inc. All rights reserved.

A role for the JAK-STAT1 pathway in blocking replication of HSV-1 in dendritic cells and macrophages

PubMed Central

Mott, Kevin R; UnderHill, David; Wechsler, Steven L; Town, Terrence; Ghiasi, Homayon

2009-01-01

Background Macrophages and dendritic cells (DCs) play key roles in host defense against HSV-1 infection. Although macrophages and DCs can be infected by herpes simplex virus type 1 (HSV-1), both cell types are resistant to HSV-1 replication. The aim of our study was to determine factor (s) that are involved in the resistance of DCs and macrophages to productive HSV-1 infection. Results We report here that, in contrast to bone marrow-derived DCs and macrophages from wild type mice, DCs and macrophages isolated from signal transducers and activators of transcription-1 deficient (STAT1-/-) mice were susceptible to HSV-1 replication and the production of viral mRNAs and DNA. There were differences in expression of immediate early, early, and late gene transcripts between STAT1+/+ and STAT1-/- infected APCs. Conclusion These results suggest for the first time that the JAK-STAT1 pathway is involved in blocking replication of HSV-1 in DCs and macrophages. PMID:19439086

[The physiology of glucagon-like peptide-1 and its role in the pathophysiology of type 2 diabetes mellitus].

PubMed

Escalada, Francisco Javier

2014-09-01

The hormone glucagon-like peptide-1 (GLP-1) is synthesized and secreted by L cells in the small intestine in response to food ingestion. After reaching the general circulation it has a half-life of 2-3 minutes due to degradation by the enzyme dipeptidyl peptidase-4. Its physiological role is directed to control plasma glucose concentration, though GLP-1 also plays other different metabolic functions following nutrient absorption. Biological activities of GLP-1 include stimulation of insulin biosynthesis and glucose-dependent insulin secretion by pancreatic beta cell, inhibition of glucagon secretion, delay of gastric emptying and inhibition of food intake. GLP-1 is able to reduce plasma glucose levels in patients with type 2 diabetes and also can restore beta cell sensitivity to exogenous secretagogues, suggesting that the increasing GLP-1 concentration may be an useful therapeutic strategy for the treatment of patients with type 2 diabetes. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

IFN-Dependent and -Independent Reduction in West Nile Virus Infectivity in Human Dermal Fibroblasts

PubMed Central

Hoover, Lisa I.; Fredericksen, Brenda L.

2014-01-01

Although dermal fibroblasts are one of the first cell types exposed to West Nile virus (WNV) during a blood meal by an infected mosquito, little is known about WNV replication within this cell type. Here, we demonstrate that neuroinvasive, WNV-New York (WNV-NY), and nonneuroinvasive, WNV-Australia (WNV-AUS60) strains are able to infect and replicate in primary human dermal fibroblasts (HDFs). However, WNV-AUS60 replication and spread within HDFs was reduced compared to that of WNV-NY due to an interferon (IFN)-independent reduction in viral infectivity early in infection. Additionally, replication of both strains was constrained late in infection by an IFN-β-dependent reduction in particle infectivity. Overall, our data indicates that human dermal fibroblasts are capable of supporting WNV replication; however, the low infectivity of particles produced from HDFs late in infection suggests that this cell type likely plays a limited role as a viral reservoir in vivo. PMID:24662674

Drosophila neuroglian: a member of the immunoglobulin superfamily with extensive homology to the vertebrate neural adhesion molecule L1.

PubMed

Bieber, A J; Snow, P M; Hortsch, M; Patel, N H; Jacobs, J R; Traquina, Z R; Schilling, J; Goodman, C S

1989-11-03

Drosophila neuroglian is an integral membrane glycoprotein that is expressed on a variety of cell types in the Drosophila embryo, including expression on a large subset of glial and neuronal cell bodies in the central and peripheral nervous systems and on the fasciculating axons that extend along them. Neuroglian cDNA clones were isolated by expression cloning. cDNA sequence analysis reveals that neuroglian is a member of the immunoglobulin superfamily. The extracellular portion of the protein consists of six immunoglobulin C2-type domains followed by five fibronectin type III domains. Neuroglian is closely related to the immunoglobulin-like vertebrate neural adhesion molecules and, among them, shows most extensive homology to mouse L1. Its homology to L1 and its embryonic localization suggest that neuroglian may play a role in neural and glial cell adhesion in the developing Drosophila embryo. We report here on the identification of a lethal mutation in the neuroglian gene.

Keeping the Wolves at Bay: Antitoxins of Prokaryotic Type II Toxin-Antitoxin Systems.

PubMed

Chan, Wai Ting; Espinosa, Manuel; Yeo, Chew Chieng

2016-01-01

In their initial stages of discovery, prokaryotic toxin-antitoxin (TA) systems were confined to bacterial plasmids where they function to mediate the maintenance and stability of usually low- to medium-copy number plasmids through the post-segregational killing of any plasmid-free daughter cells that developed. Their eventual discovery as nearly ubiquitous and repetitive elements in bacterial chromosomes led to a wealth of knowledge and scientific debate as to their diversity and functionality in the prokaryotic lifestyle. Currently categorized into six different types designated types I-VI, type II TA systems are the best characterized. These generally comprised of two genes encoding a proteic toxin and its corresponding proteic antitoxin, respectively. Under normal growth conditions, the stable toxin is prevented from exerting its lethal effect through tight binding with the less stable antitoxin partner, forming a non-lethal TA protein complex. Besides binding with its cognate toxin, the antitoxin also plays a role in regulating the expression of the type II TA operon by binding to the operator site, thereby repressing transcription from the TA promoter. In most cases, full repression is observed in the presence of the TA complex as binding of the toxin enhances the DNA binding capability of the antitoxin. TA systems have been implicated in a gamut of prokaryotic cellular functions such as being mediators of programmed cell death as well as persistence or dormancy, biofilm formation, as defensive weapons against bacteriophage infections and as virulence factors in pathogenic bacteria. It is thus apparent that these antitoxins, as DNA-binding proteins, play an essential role in modulating the prokaryotic lifestyle whilst at the same time preventing the lethal action of the toxins under normal growth conditions, i.e., keeping the proverbial wolves at bay. In this review, we will cover the diversity and characteristics of various type II TA antitoxins. We shall also look into some interesting deviations from the canonical type II TA systems such as tripartite TA systems where the regulatory role is played by a third party protein and not the antitoxin, and a unique TA system encoding a single protein with both toxin as well as antitoxin domains.

Keeping the Wolves at Bay: Antitoxins of Prokaryotic Type II Toxin-Antitoxin Systems

PubMed Central

Chan, Wai Ting; Espinosa, Manuel; Yeo, Chew Chieng

2016-01-01

In their initial stages of discovery, prokaryotic toxin-antitoxin (TA) systems were confined to bacterial plasmids where they function to mediate the maintenance and stability of usually low- to medium-copy number plasmids through the post-segregational killing of any plasmid-free daughter cells that developed. Their eventual discovery as nearly ubiquitous and repetitive elements in bacterial chromosomes led to a wealth of knowledge and scientific debate as to their diversity and functionality in the prokaryotic lifestyle. Currently categorized into six different types designated types I–VI, type II TA systems are the best characterized. These generally comprised of two genes encoding a proteic toxin and its corresponding proteic antitoxin, respectively. Under normal growth conditions, the stable toxin is prevented from exerting its lethal effect through tight binding with the less stable antitoxin partner, forming a non-lethal TA protein complex. Besides binding with its cognate toxin, the antitoxin also plays a role in regulating the expression of the type II TA operon by binding to the operator site, thereby repressing transcription from the TA promoter. In most cases, full repression is observed in the presence of the TA complex as binding of the toxin enhances the DNA binding capability of the antitoxin. TA systems have been implicated in a gamut of prokaryotic cellular functions such as being mediators of programmed cell death as well as persistence or dormancy, biofilm formation, as defensive weapons against bacteriophage infections and as virulence factors in pathogenic bacteria. It is thus apparent that these antitoxins, as DNA-binding proteins, play an essential role in modulating the prokaryotic lifestyle whilst at the same time preventing the lethal action of the toxins under normal growth conditions, i.e., keeping the proverbial wolves at bay. In this review, we will cover the diversity and characteristics of various type II TA antitoxins. We shall also look into some interesting deviations from the canonical type II TA systems such as tripartite TA systems where the regulatory role is played by a third party protein and not the antitoxin, and a unique TA system encoding a single protein with both toxin as well as antitoxin domains. PMID:27047942

The influence of macrophages and the tumor microenvironment on natural killer cells.

PubMed

Krneta, T; Gillgrass, A; Ashkar, A A

2013-01-01

Numerous reviews in the field of NK cell biology dictate the pivotal role that NK cells play in tumor rejection. Although these cell types were originally described based on their cytotoxic ability, we now know that NK cells are not naturally born to kill. Both cellular interactions and the local environment in which the NK cell resides in may influence its cytotoxic functions. Just as organ specific NK cells have distinct phenotypic and functional differences, the tumor is a unique microenvironment in itself. The NK cells originally recruited to the tumor site are able to stimulate immune responses and aid in tumor destruction but eventually become persuaded otherwise by mechanisms of immunosuppression. Here, we review potential mechanisms and players involved in NK cell immunosuppression. In particular the effects of another innate immune player, macrophages, will be addressed in augmenting immunosuppression of NK cells within tumors. Tumor-associated macrophages (TAMs) are the main regulatory population of myeloid cells in the tumor and are characterized by their ability to promote tumor cell proliferation and metastasis. In addition, they express/release immunoregulatory factors which have been shown to directly inhibit NK cell function. Understanding how these two cell types interact in the distinct tumor microenvironment will allow us to consider therapies that target TAMs to promote enhanced NK cell activity.

Effects of temperature and cellular interactions on the mechanics and morphology of human cancer cells investigated by atomic force microscopy.

PubMed

Li, Mi; Liu, LianQing; Xi, Ning; Wang, YueChao; Xiao, XiuBin; Zhang, WeiJing

2015-09-01

Cell mechanics plays an important role in cellular physiological activities. Recent studies have shown that cellular mechanical properties are novel biomarkers for indicating the cell states. In this article, temperature-controllable atomic force microscopy (AFM) was applied to quantitatively investigate the effects of temperature and cellular interactions on the mechanics and morphology of human cancer cells. First, AFM indenting experiments were performed on six types of human cells to investigate the changes of cellular Young's modulus at different temperatures and the results showed that the mechanical responses to the changes of temperature were variable for different types of cancer cells. Second, AFM imaging experiments were performed to observe the morphological changes in living cells at different temperatures and the results showed the significant changes of cell morphology caused by the alterations of temperature. Finally, by co-culturing human cancer cells with human immune cells, the mechanical and morphological changes in cancer cells were investigated. The results showed that the co-culture of cancer cells and immune cells could cause the distinct mechanical changes in cancer cells, but no significant morphological differences were observed. The experimental results improved our understanding of the effects of temperature and cellular interactions on the mechanics and morphology of cancer cells.

The coordination of ploidy and cell size differs between cell layers in leaves

PubMed Central

Katagiri, Yohei; Hasegawa, Junko; Fujikura, Ushio; Hoshino, Rina; Matsunaga, Sachihiro; Tsukaya, Hirokazu

2016-01-01

Growth and developmental processes are occasionally accompanied by multiple rounds of DNA replication, known as endoreduplication. Coordination between endoreduplication and cell size regulation often plays a crucial role in proper organogenesis and cell differentiation. Here, we report that the level of correlation between ploidy and cell volume is different in the outer and inner cell layers of leaves of Arabidopsis thaliana using a novel imaging technique. Although there is a well-known, strong correlation between ploidy and cell volume in pavement cells of the epidermis, this correlation was extremely weak in palisade mesophyll cells. Induction of epidermis cell identity based on the expression of the homeobox gene ATML1 in mesophyll cells enhanced the level of correlation between ploidy and cell volume to near that of wild-type epidermal cells. We therefore propose that the correlation between ploidy and cell volume is regulated by cell identity. PMID:26903507

Normal Untreated Jurkat Cells

NASA Technical Reports Server (NTRS)

2004-01-01

Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. The objective of the research was to define a way to differentiate between effects due to microgravity and those due to possible stress from non-optimal spaceflight conditions. These Jurkat cells, a human acute T-cell leukemia was obtained to evaluate three types of potential experimental stressors: a) Temperature elevation; b) Serum starvation; and c) Centrifugal force. The data from previous spaceflight experiments showed that actin filaments and cell shape are significantly different for the control. These normal cells serve as the baseline for future spaceflight experiments.

The Epstein-Barr Virus (EBV) in T Cell and NK Cell Lymphomas: Time for a Reassessment

PubMed Central

Gru, A. A.; Haverkos, B. H.; Freud, A. G.; Hastings, J.; Nowacki, N. B.; Barrionuevo, C.; Vigil, C. E.; Rochford, R.; Natkunam, Y.; Baiocchi, R. A.

2015-01-01

While Epstein-Barr virus (EBV) was initially discovered and characterized as an oncogenic virus in B cell neoplasms, it also plays a complex and multifaceted role in T/NK cell lymphomas. In B cell lymphomas, EBV-encoded proteins have been shown to directly promote immortalization and proliferation through stimulation of the NF-κB pathway and increased expression of anti-apoptotic genes. In the context of mature T/NK lymphomas (MTNKL), with the possible exception on extranodal NK/T cell lymphoma (ENKTL), the virus likely plays a more diverse and nuanced role. EBV has been shown to shape the tumor microenvironment by promoting Th2-skewed T cell responses and by increasing the expression of the immune checkpoint ligand PD-L1. The type of cell infected, the amount of plasma EBV DNA, and the degree of viral lytic replication have all been proposed to have prognostic value in T/NK cell lymphomas. Latency patterns of EBV infection have been defined using EBV-infected B cell models and have not been definitively established in T/NK cell lymphomas. Identifying the expression profile of EBV lytic proteins could allow for individualized therapy with the use of antiviral medications. More work needs to be done to determine whether EBV-associated MTNKL have distinct biological and clinical features, which can be leveraged for risk stratification, disease monitoring, and therapeutic purposes. PMID:26449716

Induction of endothelial cell proliferation by angiogenic factors released by activated monocytes

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

Pakala, Rajbabu; Watanabe, Takuya; Benedict, Claude R

2002-06-01

Introduction: Cell-cell interaction is an essential component of atherosclerotic plaque development. Activated monocytes appear to play a central role in the development of atherosclerosis, not only through foam cell formation but also via the production of various growth factors that induce proliferation of different cell types that are involved in the plaque development. Using serum free co-culture method, we determined the effect of monocytes on endothelial cell proliferation. Methods: Endothelial cell proliferation is determined by the amount of [{sup 3}H]thymidine incorporated in to the DNA. Basic fibroblast growth factor (b-FGF), vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8) levels inmore » the conditioned medium were determined by ELISA. Results: Conditioned medium from unactivated monocytes partially inhibited endothelial cell proliferation, whereas conditioned medium from activated monocytes promoted endothelial cell proliferation. The mitogenic effect of conditioned medium derived from activated monocytes is due to the presence of b-FGF, VEGF and IL-8. Neutralizing antibodies against b-FGF, VEGF and IL-8 partially reversed the mitogenic effect of conditioned medium derived from activated monocytes. When b-FGF, VEGF and IL-8 were immunoprecipitated from conditioned medium derived from activated monocytes, it is less mitogenic to endothelial cells. Conclusion: Activated monocytes may play an important role in the development of atherosclerotic plaque by producing endothelial cell growth factors.« less

Mammary Gland Tumor Development in Transgenic Mice Overexpressing Different Isoforms of the CDP/Cux Transcription Factor

DTIC Science & Technology

2008-03-01

were found to be overexpressed in breast cancer cell lines, in human breast tumors and in uterine leiomyomas , suggesting that these proteins play a...1-4). In addition, short CUX1 isoforms were found to be overexpressed in breast cancer cell lines, in human breast tumors and in uterine leiomyomas ...alternative mRNA. The p110 and p75 isoforms are overexpressed in different types of cancers, such as in leiomyomas and breast cancers. In tissue culture

Mammary Gland Tumor Development in Transgenic Mice Overexpressing Different Isoforms of the CDP/Cux Transcription Factor

DTIC Science & Technology

2007-03-01

overexpressed in breast cancer cell lines, in human breast tumors and in uterine leiomyomas , suggesting that these proteins play a key role in tumor...isoforms were found to be overexpressed in breast cancer cell lines, in human breast tumors and in uterine leiomyomas , suggesting that these proteins...G1/S transition. In addition, the p110 and p75 isoforms are overexpressed in different types of human cancers, such as in leiomyomas and breast

Customizing the targeting of IGF-1 receptor.

PubMed

Baserga, Renato

2009-02-01

The type 1 IGF receptor (IGF-IR) is activated by two ligands, IGF-1 and IGF-2, and by insulin at supraphysiological concentrations. It plays a significant role in the growth of normal and abnormal cells, and antibodies against the IGF-IR are now in clinical trials. Targeting of the IGF-IR in cancer cells (by antibodies or other means) can be improved by the appropriate selection of responsive tumors. This review focuses on the optimization of IGF-IR targeting in human cancer.

The Role of Shewanella oneidensis MR-1 Outer Surface Structures in Extracellular Electron Transfer

DTIC Science & Technology

2010-01-01

Supernatants from the wells of the air-exposed VBSA that had been in operation for 220 h were harvested and planktonic cells were removed via...prepilins. In some bacteria, such as Pseudomonas aerugino- sa and Vibrio cholerae, PilD plays a dual role and processes type IVand T2SS prepilins [38 – 41... harvested from the VBSA at the times indicated by arrows in Fig. 4 (100 h data not shown). Fig. 6. Presence of riboflavin in cell-free supernatants

Regulation of cytokine polarization and T cell recruitment to inflamed paws in mouse collagen-induced arthritis by the chemokine receptor CXCR6.

PubMed

Slauenwhite, Drew; Gebremeskel, Simon; Doucette, Carolyn D; Hoskin, David W; Johnston, Brent

2014-11-01

The chemokine receptor CXCR6 is highly expressed on lymphocytes isolated from the synovium of patients with rheumatoid arthritis, psoriatic arthritis, or juvenile idiopathic arthritis, suggesting that CXCR6 regulates immune cell activation or infiltration into arthritic joints. This study was undertaken to examine the role of CXCR6 in T cell activation and arthritis development. A collagen-induced arthritis model was used to examine arthritis development in wild-type and CXCR6(-/-) mice. CXCR6 expression, lymphocyte accumulation, and intracellular cytokine production were examined by flow cytometry. Collagen-specific antibodies were measured in the serum. Collagen-specific recall responses were examined in vitro via proliferation and cytokine release assays. T cell homing to inflamed joints was examined using competitive adoptive transfer of dye-labeled lymphocytes from wild-type and CXCR6(-/-) mice. The numbers of CXCR6+ T cells were increased in the paws and draining lymph nodes of arthritic mice. The incidence of arthritis, disease severity, extent of T cell accumulation, and levels of collagen-specific IgG2a antibodies were significantly reduced in CXCR6(-/-) mice compared to wild-type mice. T cells from wild-type mice exhibited Th1 (interferon-γ [IFNγ]) polarization in the inguinal lymph nodes following immunization. At disease peak, this shifted to a Th17 (interleukin-17A [IL-17A]) response in the popliteal lymph nodes. T cells in CXCR6(-/-) mice exhibited impaired cytokine polarization, resulting in a decreased frequency and number of IL-17A- and IFNγ-producing cells. Recruitment of activated CXCR6(-/-) mouse T cells to the inflamed paws was impaired compared to recruitment of wild-type mouse T cells. These experiments demonstrate that CXCR6 plays important roles in the pathogenesis of arthritis through its effects on both T cell cytokine polarization and homing of T cells to inflamed joints. Copyright © 2014 by the American College of Rheumatology.

Differential requirements for the Ets transcription factor Elf-1 in the development of NKT cells and NK cells

PubMed Central

Choi, Hak-Jong; Geng, Yanbiao; Cho, Hoonsik; Li, Sha; Giri, Pramod Kumar; Felio, Kyrie

2011-01-01

E26 Transformation specific (Ets) family transcription factors control the expression of a large number of genes regulating hematopoietic cell development and function. Two such transcription factors, Ets-1 and myeloid Elf-1–like factor (MEF), have been shown to play critical roles in both natural killer (NK)– and NKT-cell development, but not in the development of conventional T cells. In this study, we address the role of E74-like factor 1 (Elf-1), another Ets family transcription factor that is closely related to MEF but divergent from Ets-1, in NK- and NKT-cell development using Elf-1–deficient (Elf-1−/−) mice. Whereas the proportion of NK cells in Elf-1−/− mice was normal, the proportion of NKT cells was significantly reduced in the thymus and periphery of Elf-1−/− mice compared with wild-type (WT) mice. Although Ets-1–deficient mice lack NKT cells altogether, Elf-1−/− mice exhibited only a partial block in NKT-cell development caused by a cell-intrinsic defect in the selection, survival, and maturation of NKT cells. In addition, residual NKT cells found in Elf-1−/− mice produced less cytokine upon antigen stimulation compared with WT NKT cells. Our data demonstrate that Elf-1 plays an important and nonredundant role in the development and function of NKT cells, but is not involved in NK-cell development. PMID:21148815

Oxidative Stress in Diabetes: Implications for Vascular and Other Complications

PubMed Central

Pitocco, Dario; Tesauro, Manfredi; Alessandro, Rizzi; Ghirlanda, Giovanni; Cardillo, Carmine

2013-01-01

In recent decades, oxidative stress has become a focus of interest in most biomedical disciplines and many types of clinical research. Increasing evidence shows that oxidative stress is associated with the pathogenesis of diabetes, obesity, cancer, ageing, inflammation, neurodegenerative disorders, hypertension, apoptosis, cardiovascular diseases, and heart failure. Based on these studies, an emerging concept is that oxidative stress is the “final common pathway” through which the risk factors for several diseases exert their deleterious effects. Oxidative stress causes a complex dysregulation of cell metabolism and cell–cell homeostasis; in particular, oxidative stress plays a key role in the pathogenesis of insulin resistance and β-cell dysfunction. These are the two most relevant mechanisms in the pathophysiology of type 2 diabetes and its vascular complications, the leading cause of death in diabetic patients. PMID:24177571

Characterization and expression analysis of Galnts in developing Strongylocentrotus purpuratus embryos

PubMed Central

Famiglietti, Amber L.; Wei, Zheng; Beres, Thomas M.; Milac, Adina L.; Tran, Duy T.; Patel, Divya; Angerer, Robert C.; Angerer, Lynne M.

2017-01-01

Mucin-type O-glycosylation is a ubiquitous posttranslational modification in which N-Acetylgalactosamine (GalNAc) is added to the hydroxyl group of select serine or threonine residues of a protein by the family of UDP-GalNAc:Polypeptide N-Acetylgalactosaminyltransferases (GalNAc-Ts; EC 2.4.1.41). Previous studies demonstrate that O-glycosylation plays essential roles in protein function, cell-cell interactions, cell polarity and differentiation in developing mouse and Drosophila embryos. Although this type of protein modification is highly conserved among higher eukaryotes, little is known about this family of enzymes in echinoderms, basal deuterostome relatives of the chordates. To investigate the potential role of GalNAc-Ts in echinoderms, we have begun the characterization of this enzyme family in the purple sea urchin, S. purpuratus. We have fully or partially cloned a total of 13 genes (SpGalnts) encoding putative sea urchin SpGalNAc-Ts, and have confirmed enzymatic activity of five recombinant proteins. Amino acid alignments revealed high sequence similarity among sea urchin and mammalian glycosyltransferases, suggesting the presence of putative orthologues. Structural models underscored these similarities and helped reconcile some of the substrate preferences observed. Temporal and spatial expression of SpGalnt transcripts, was studied by whole-mount in situ hybridization. We found that many of these genes are transcribed early in developing embryos, often with restricted expression to the endomesodermal region. Multicolor fluorescent in situ hybridization (FISH) demonstrated that transcripts encoding SpGalnt7-2 co-localized with both Endo16 (a gene expressed in the endoderm), and Gcm (a gene expressed in secondary mesenchyme cells) at the early blastula stage, 20 hours post fertilization (hpf). At late blastula stage (28 hpf), SpGalnt7-2 message co-expresses with Gcm, suggesting that it may play a role in secondary mesenchyme development. We also discovered that morpholino-mediated knockdown of SpGalnt13 transcripts, results in a deficiency of embryonic skeleton and neurons, suggesting that mucin-type O-glycans play essential roles during embryonic development in S. purpuratus. PMID:28448610

Abnormal gastrointestinal endocrine cells in patients with diabetes type 1: relationship to gastric emptying and myoelectrical activity.

PubMed

El-Salhy, M; Sitohy, B

2001-11-01

Gastrointestinal symptoms in patients with diabetes are believed to be caused by gastrointestinal dysmotility and secretion/absorption disturbances, and the gut endocrine cells play an important part in regulating these two functions. Studies on animal models of human diabetes type I revealed abnormality in these cells, but it is unknown whether abnormality also occurs in patients with diabetes. Eleven patients with long duration of diabetes type I and organ complications, as well as gastrointestinal symptoms, were studied. Endocrine cells in different segments of the gastrointestinal tract were detected by immunocytochemistry and quantified by computerized image analysis. Gastric emptying was measured by scintigraphy and gastric myoelectric activity was determined by electrogastrography. An abnormal density of gastrointestinal endocrine cells was found in patients with diabetes. This abnormality occurred in all segments of the upper and lower gastrointestinal tract investigated, and included most of the endocrine cell types. The patients showed delayed gastric emptying, which correlated closely with the acute glucose level, but did not correlate with HbA1c. Gastric emptying also correlated closely with the density of duodenal serotonin and secretin cells. The patients exhibited bradygastrias and tachygastrias. These dysrhythmias, however, did not differ significantly from controls. The endocrine cells are the anatomical units responsible for the production of gut hormones, and the change in their density would reflect a change in the capacity of producing these hormones. The abnormality in density of the gastrointestinal endocrine cells may contribute to the development of gastrointestinal dysmotility and the symptoms encountered in patients with diabetes.

Advanced catalyst supports for PEM fuel cell cathodes

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

Du, Lei; Shao, Yuyan; Sun, Junming

2016-11-01

Electrocatalyst support materials are key components for polymer exchange membrane (PEM) fuel cells, which play a critical role in determining electrocatalyst durability and activity, mass transfer and water management. The commonly-used supports, e.g. porous carbon black, cannot meet all the requirements under the harsh operation condition of PEM fuel cells. Great efforts have been made in the last few years in developing alternative support materials. In this paper, we selectively review recent progress on three types of important support materials: carbon, non-carbon and hybrid carbon-oxides nanocomposites. A perspective on future R&D of electrocatalyst support materials is also provided.

Niemann-Pick type C2 protein regulates liver cancer progression via modulating ERK1/2 pathway: Clinicopathological correlations and therapeutical implications.

PubMed

Liao, Yi-Jen; Fang, Cheng-Chieh; Yen, Chia-Hung; Hsu, Shih-Ming; Wang, Chung-Kwe; Huang, Shiu-Feng; Liang, Yu-Chih; Lin, Ying-Yu; Chu, Yu-Tseng; Arthur Chen, Yi-Ming

2015-09-15

Primary hepatocellular carcinoma (HCC) is the fifth most common malignancy worldwide and the third leading cause of cancer-related death. It is important to identify new targets for early diagnosis and treatment of HCC. Niemann-Pick type C2 (NPC2) plays an important role in the regulation of intracellular cholesterol homeostasis via direct binding with free cholesterol. However, little is known about the significance of NPC2 in HCC tumorigenesis. In this study, we showed that NPC2 is abundantly expressed in normal liver, but is downregulated in human HCC tissues. The patients with NPC2 downregulation expressed much higher α-fetoprotein, multiple tumor type, vascular invasion, later pathological stage and shorter survival rate. Knockdown NPC2 in liver cancer cell lines promote cell proliferation, migration and xenograft tumorigenesis. In contrast, NPC2 overexpression inhibits HuH7 promoted tumor growth. Furthermore, administration of hepatotropic adeno-associated virus 8 (AAV8) delivered NPC2 decreased the inflammatory infiltration, the expression of two early HCC markers-glypican 3 and survivin and suppressed the spontaneous HCC development in mice. To identify the NPC2-dependent mechanism, we emphasized on the status of MAPK/ERK signaling. MEK1/2 inhibitor treatment demonstrated that the expression of NPC2 affected the activation of ERK1/2 but not MEK1/2. In addition, cholesterol trafficking inhibitor treatment did not alter the cell proliferation and the activation of MEK/ERK. In conclusion, our study demonstrates that NPC2 may play an important role in negatively regulate cell proliferation and ERK1/2 activation that were independent of cholesterol accumulation. AAV-NPC2 may thus represent a new treatment strategy for liver cancer. © 2015 UICC.

Exosomes and nanotubes: control of immune cell communication

PubMed Central

McCoy-Simandle, Kessler; Hanna, Samer J.; Cox, Dianne

2015-01-01

Cell-cell communication is critical to coordinate the activity and behavior of a multicellular organism. The cells of the immune system not only must communicate with similar cells, but also with many other cell types in the body. Therefore, the cells of the immune system have evolved multiple ways to communicate. Exosomes and tunneling nanotubes (TNTs) are two means of communication used by immune cells that contribute to immune functions. Exosomes are small membrane vesicles secreted by most cell types that can mediate intercellular communication and in the immune system they are proposed to play a role in antigen presentation and modulation of gene expression. TNTs are membranous structures that mediate direct cell-cell contact over several cell diameters in length (and possibly longer) and facilitate the interaction and/or the transfer of signals, material and other cellular organelles between connected cells. Recent studies have revealed additional, but sometimes conflicting, structural and functional features of both exosomes and TNTs. Despite the new and exciting information in exosome and TNT composition, origin and in vitro function, biologically significant functions are still being investigated and determined. In this review, we discuss the current field regarding exosomes and TNTs in immune cells providing evaluation and perspectives of the current literature. PMID:26704468

Titan Cell Production Enhances the Virulence of Cryptococcus neoformans

PubMed Central

Crabtree, Juliet N.; Okagaki, Laura H.; Wiesner, Darin L.; Strain, Anna K.; Nielsen, Judith N.

2012-01-01

Infection with Cryptococcus neoformans begins when desiccated yeast cells or spores are inhaled and lodge in the alveoli of the lungs. A subset of cryptococcal cells in the lungs differentiate into enlarged cells, referred to as titan cells. Titan cells can be as large as 50 to 100 μm in diameter and exhibit a number of features that may affect interactions with host immune defenses. To characterize the effect of titan cell formation on the host-pathogen interaction, we utilized a previously described C. neoformans mutant, the gpr4Δ gpr5Δ mutant, which has minimal titan cell production in vivo. The gpr4Δ gpr5Δ mutant strain had attenuated virulence, a lower CFU, and reduced dissemination compared to the wild-type strain. Titan cell production by the wild-type strain also resulted in increased eosinophil accumulation and decreased phagocytosis in the lungs compared to those with the gpr4Δ gpr5Δ mutant strain. Phagocytosed cryptococcal cells exhibited less viability than nonphagocytosed cells, which potentially explains the reduced cell survival and overall attenuation of virulence in the absence of titan cells. These data show that titan cell formation is a novel virulence factor in C. neoformans that promotes establishment of the initial pulmonary infection and plays a key role in disease progression. PMID:22890995

Titan cell production enhances the virulence of Cryptococcus neoformans.

PubMed

Crabtree, Juliet N; Okagaki, Laura H; Wiesner, Darin L; Strain, Anna K; Nielsen, Judith N; Nielsen, Kirsten

2012-11-01

Infection with Cryptococcus neoformans begins when desiccated yeast cells or spores are inhaled and lodge in the alveoli of the lungs. A subset of cryptococcal cells in the lungs differentiate into enlarged cells, referred to as titan cells. Titan cells can be as large as 50 to 100 μm in diameter and exhibit a number of features that may affect interactions with host immune defenses. To characterize the effect of titan cell formation on the host-pathogen interaction, we utilized a previously described C. neoformans mutant, the gpr4Δ gpr5Δ mutant, which has minimal titan cell production in vivo. The gpr4Δ gpr5Δ mutant strain had attenuated virulence, a lower CFU, and reduced dissemination compared to the wild-type strain. Titan cell production by the wild-type strain also resulted in increased eosinophil accumulation and decreased phagocytosis in the lungs compared to those with the gpr4Δ gpr5Δ mutant strain. Phagocytosed cryptococcal cells exhibited less viability than nonphagocytosed cells, which potentially explains the reduced cell survival and overall attenuation of virulence in the absence of titan cells. These data show that titan cell formation is a novel virulence factor in C. neoformans that promotes establishment of the initial pulmonary infection and plays a key role in disease progression.

Enhanced peripheral dopamine impairs post-ischemic healing by suppressing angiotensin receptor type 1 expression in endothelial cells and inhibiting angiogenesis.

PubMed

Sarkar, Chandrani; Ganju, Ramesh K; Pompili, Vincent J; Chakroborty, Debanjan

2017-02-01

Increased circulating catecholamines have been linked with cardiovascular anomalies as well as with peripheral vascular diseases. Although the roles of epinephrine and norepinephrine have received considerable attention, the role of the other catecholamine, dopamine, has been less studied. Since dopamine is a potent endogenous inhibitor of angiogenesis and as angiogenesis is essential for ischemic healing, we therefore studied the role played by dopamine during ischemic healing using dopamine D 2 receptor knockout (KOD2) mice. Although concentration of dopamine and its rate-limiting enzyme, tyrosine hydroxylase, was considerably high in the muscle tissues of wild-type and KOD2 mice with unilateral hind limb ischemia (HLI), recovery was significantly faster in the KOD2 mice compared to the wild-type controls, thereby indicating that peripheral dopamine might have a role in this healing process. In addition, we observed significant differences in post-ischemic angiogenesis between these two groups. Our study further revealed that elevated dopamine independently suppressed activation of local tissue-based renin-angiotensin system (RAS), a critical growth factor system stimulating angiogenesis in ischemia. Angiotensin II (ATII) and its receptor, angiotensin receptor type 1 (AT1R), are the key players in RAS-mediated angiogenesis. Dopamine acting through its D 2 receptors in endothelial cells inhibited ATII-mediated angiogenesis by suppressing the expression of AT1R in these cells. This study thus for the first time demonstrates the role played by dopamine in prolonging post-ischemic recovery. Therefore, pharmacological intervention inhibiting the action of dopamine holds promise as future therapeutic strategy for the treatment of HLI and other peripheral arterial diseases.

Invasion of Epithelial Cells and Proteolysis of Cellular Focal Adhesion Components by Distinct Types of Porphyromonas gingivalis Fimbriae

PubMed Central

Nakagawa, Ichiro; Inaba, Hiroaki; Yamamura, Taihei; Kato, Takahiro; Kawai, Shinji; Ooshima, Takashi; Amano, Atsuo

2006-01-01

Porphyromonas gingivalis fimbriae are classified into six types (types I to V and Ib) based on the fimA genes encoding FimA (a subunit of fimbriae), and they play a critical role in bacterial interactions with host tissues. In this study, we compared the efficiencies of P. gingivalis strains with distinct types of fimbriae for invasion of epithelial cells and for degradation of cellular focal adhesion components, paxillin, and focal adhesion kinase (FAK). Six representative strains with the different types of fimbriae were tested, and P. gingivalis with type II fimbriae (type II P. gingivalis) adhered to and invaded epithelial cells at significantly greater levels than the other strains. There were negligible differences in gingipain activities among the six strains; however, type II P. gingivalis apparently degraded intracellular paxillin in association with a loss of phosphorylation 30 min after infection. Degradation was blocked with cytochalasin D or in mutants with fimA disrupted. Paxillin was degraded by the mutant with Lys-gingipain disrupted, and this degradation was prevented by inhibition of Arg-gingipain activity by Nα-p-tosyl-l-lysine chloromethyl ketone. FAK was also degraded by type II P. gingivalis. Cellular focal adhesions with green fluorescent protein-paxillin macroaggregates were clearly destroyed, and this was associated with cellular morphological changes and microtubule disassembly. In an in vitro wound closure assay, type II P. gingivalis significantly inhibited cellular migration and proliferation compared to the cellular migration and proliferation observed with the other types. These results suggest that type II P. gingivalis efficiently invades epithelial cells and degrades focal adhesion components with Arg-gingipain, which results in cellular impairment during wound healing and periodontal tissue regeneration. PMID:16790749

Characterization and optimization of cell seeding in scaffolds by factorial design: quality by design approach for skeletal tissue engineering.

PubMed

Chen, Yantian; Bloemen, Veerle; Impens, Saartje; Moesen, Maarten; Luyten, Frank P; Schrooten, Jan

2011-12-01

Cell seeding into scaffolds plays a crucial role in the development of efficient bone tissue engineering constructs. Hence, it becomes imperative to identify the key factors that quantitatively predict reproducible and efficient seeding protocols. In this study, the optimization of a cell seeding process was investigated using design of experiments (DOE) statistical methods. Five seeding factors (cell type, scaffold type, seeding volume, seeding density, and seeding time) were selected and investigated by means of two response parameters, critically related to the cell seeding process: cell seeding efficiency (CSE) and cell-specific viability (CSV). In addition, cell spatial distribution (CSD) was analyzed by Live/Dead staining assays. Analysis identified a number of statistically significant main factor effects and interactions. Among the five seeding factors, only seeding volume and seeding time significantly affected CSE and CSV. Also, cell and scaffold type were involved in the interactions with other seeding factors. Within the investigated ranges, optimal conditions in terms of CSV and CSD were obtained when seeding cells in a regular scaffold with an excess of medium. The results of this case study contribute to a better understanding and definition of optimal process parameters for cell seeding. A DOE strategy can identify and optimize critical process variables to reduce the variability and assists in determining which variables should be carefully controlled during good manufacturing practice production to enable a clinically relevant implant.

Synthesis of prolyl 4-hydroxylase alpha subunit and type IV collagen in hemocytic granular cells of silkworm, Bombyx mori: Involvement of type IV collagen in self-defense reaction and metamorphosis.

PubMed

Adachi, Takahiro; Tomita, Masahiro; Yoshizato, Katsutoshi

2005-04-01

The present study shows that hemocytic granular cells synthesize and secrete type IV collagen (ColIV) in the silkworm Bombyx mori (B. mori) and suggests that these cells play roles in the formation of basement membrane, the encapsulation of foreign bodies, and the metamorphic remodeling of the gut. The full- and partial-length cDNA of B. mori prolyl 4-hydroxylase alpha subunit (BmP4Halpha) and B. mori ColIV (BmColIV) were cloned, respectively. In situ hybridization and immunocytochemistry on larval tissues and cells identified hemocytic granular cells as the cells that express mRNAs and proteins of both BmP4Halpha and BmColIV. Immunohistochemistry and immunocytochemistry demonstrated that BmColIV was present in the basement membrane and in the secretory granules of granular cells, respectively. Granular cells in culture secreted BmColIV without accompanying the degranulation and discharged it from the granules when the cells were degranulated. Nylon threads were inserted into the hemocoel of larvae. Granular cells concentrated around the nylon threads and encapsulated them as a self-defense reaction. BmColIV was found to be a component of the capsules. Furthermore, the present study showed that actively BmColIV-expressing granular cells accumulated around the midgut epithelium and formed BmColIV-rich thick basal lamina-like structures there in larval to pupal metamorphosis.

Characterization and structural analysis of wild type and a non-abscission mutant at the development funiculus (Def) locus in Pisum sativum L.

PubMed

Ayeh, Kwadwo Owusu; Lee, YeonKyeong; Ambrose, Mike J; Hvoslef-Eide, Anne Kathrine

2009-06-23

In pea seeds (Pisum sativum L.), the Def locus defines an abscission event where the seed separates from the funicle through the intervening hilum region at maturity. A spontaneous mutation at this locus results in the seed failing to abscise from the funicle as occurs in wild type peas. In this work, structural differences between wild type peas that developed a distinct abscission zone (AZ) between the funicle and the seed coat and non-abscission def mutant were characterized. A clear abscission event was observed in wild type pea seeds that were associated with a distinct double palisade layers at the junction between the seed coat and funicle. Generally, mature seeds fully developed an AZ, which was not present in young wild type seeds. The AZ was formed exactly below the counter palisade layer. In contrast, the palisade layers at the junction of the seed coat and funicle were completely absent in the def mutant pea seeds and the cells in this region were seen to be extensions of surrounding parenchymatous cells. The Def wild type developed a distinct AZ associated with palisade layer and counterpalisade layer at the junction of the seed coat and funicle while the def mutant pea seed showed non-abscission and an absence of the double palisade layers in the same region. We conclude that the presence of the double palisade layer in the hilum of the wild type pea seeds plays an important structural role in AZ formation by delimiting the specific region between the seed coat and the funicle and may play a structural role in the AZ formation and subsequent detachment of the seed from the funicle.

Transitions from mono- to co- to tri-culture uniquely affect gene expression in breast cancer, stromal, and immune compartments

PubMed Central

Weinberger, Emma M.; Regehr, Keil J.; Berry, Scott M.; Beebe, David J.; Alarid, Elaine T.

2016-01-01

Heterotypic interactions in cancer microenvironments play important roles in disease initiation, progression, and spread. Co-culture is the predominant approach used in dissecting paracrine interactions between tumor and stromal cells, but functional results from simple co-cultures frequently fail to correlate to in vivo conditions. Though complex heterotypic in vitro models have improved functional relevance, there is little systematic knowledge of how multi-culture parameters influence this recapitulation. We therefore have employed a more iterative approach to investigate the influence of increasing model complexity; increased heterotypic complexity specifically. Here we describe how the compartmentalized and microscale elements of our multi-culture device allowed us to obtain gene expression data from one cell type at a time in a heterotypic culture where cells communicated through paracrine interactions. With our device we generated a large dataset comprised of cell type specific gene-expression patterns for cultures of increasing complexity (three cell types in mono-, co-, or tri-culture) not readily accessible in other systems. Principal component analysis indicated that gene expression was changed in co-culture but was often more strongly altered in tri-culture as compared to mono-culture. Our analysis revealed that cell type identity and the complexity around it (mono-, co-, or tri-culture) influence gene regulation. We also observed evidence of complementary regulation between cell types in the same heterotypic culture. Here we demonstrate the utility of our platform in providing insight into how tumor and stromal cells respond to microenvironments of varying complexities highlighting the expanding importance of heterotypic cultures that go beyond conventional co-culture. PMID:27432323

NFIB regulates embryonic development of submandibular glands.

PubMed

Mellas, R E; Kim, H; Osinski, J; Sadibasic, S; Gronostajski, R M; Cho, M; Baker, O J

2015-02-01

NFIB (nuclear factor I B) is a NFI transcription factor family member, which is essential for the development of a variety of organ systems. Salivary gland development occurs through several stages, including prebud, bud, pseudoglandular, canalicular, and terminal. Although many studies have been done to understand mouse submandibular gland (SMG) branching morphogenesis, little is known about SMG cell differentiation during the terminal stages. The goal of this study was to determine the role of NFIB during SMG development. We analyzed SMGs from wild-type and Nfib-deficient mice (Nfib (-/-)). At embryonic (E) day 18.5, SMGs from wild-type mice showed duct branching morphogenesis and differentiation of tubule ductal cells into tubule secretory cells. In contrast, SMGs from Nfib (-/-) mice at E18.5 failed to differentiate into tubule secretory cells while branching morphogenesis was unaffected. SMGs from wild-type mice at E16.5 displayed well-organized cuboidal inner terminal tubule cells. However, SMGs from Nfib (-/-) at E16.5 displayed disorganized inner terminal tubule cells. SMGs from wild-type mice at E18.5 became fully differentiated, as indicated by a high degree of apicobasal polarization (i.e., presence of apical ZO-1 and basolateral E-cadherin) and columnar shape. Furthermore, SMGs from wild-type mice at E18.5 expressed the protein SMGC, a marker for tubule secretory cells. However, SMGs from Nfib (-/-) mice at E18.5 showed apicobasal polarity, but they were disorganized and lost the ability to secrete SMGC. These findings indicate that the transcription factor NFIB is not required for branching morphogenesis but plays a key role in tubule cell differentiation during mouse SMG development. © International & American Associations for Dental Research 2014.

The Expression of BTS-2 Enhances Cell Growth and Invasiveness in Renal Cell Carcinoma.

PubMed

Pham, Quoc Thang; Oue, Naohide; Yamamoto, Yuji; Shigematsu, Yoshinori; Sekino, Yohei; Sakamoto, Naoya; Sentani, Kazuhiro; Uraoka, Naohiro; Tiwari, Mamata; Yasui, Wataru

2017-06-01

Renal cell carcinoma (RCC) is one of the most common types of cancer in developed countries. Bone marrow stromal cell antigen 2 (BST2) gene, which encodes BST2 transmembrane glycoprotein, is overexpressed in several cancer types. In the present study, we analyzed the expression and function of BST2 in RCC. BST2 expression was analyzed by immunohistochemistry in 123 RCC cases. RNA interference was used to inhibit BST2 expression in a RCC cell line. Immunohistochemical analysis showed that 32% of the 123 RCC cases were positive for BST2. BST2 expression was positively associated with tumour stage. Furthermore, BST2 expression was an independent predictor of survival in patients with RCC. BST2 siRNA-transfected Caki-1 cells displayed significantly reduced cell growth and invasive activity relative to negative control siRNA-transfected cells. These results suggest that BST2 plays an important role in the progression of RCC. Because BST2 is expressed on the cell membrane, BST2 is a good therapeutic target for RCC. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Local Inflammatory Cues Regulate Differentiation and Persistence of CD8+ Tissue-Resident Memory T Cells.

PubMed

Bergsbaken, Tessa; Bevan, Michael J; Fink, Pamela J

2017-04-04

Many pathogens initiate infection at mucosal surfaces, and tissue-resident memory T (Trm) cells play an important role in protective immunity, yet the tissue-specific signals that regulate Trm differentiation are poorly defined. During Yersinia infection, CD8 + T cell recruitment to areas of inflammation within the intestine is required for differentiation of the CD103 - CD69 + Trm subset. Intestinal proinflammatory microenvironments have elevated interferon (IFN)-β and interleukin-12 (IL-12), which regulated Trm markers, including CD103. Type I interferon-receptor- or IL-12-receptor-deficient T cells functioned similarly to wild-type (WT) cells during infection; however, the inability of T cells to respond to inflammation resulted in defective differentiation of CD103 - CD69 + Trm cells and reduced Trm persistence. Intestinal macrophages were the main producers of IFN-β and IL-12 during infection, and deletion of CCR2 + IL-12-producing cells reduced the size of the CD103 - Trm population. These data indicate that intestinal inflammation drives phenotypic diversity and abundance of Trm cells for optimal tissue-specific immunity. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Expression of receptors for atrial natriuretic peptide on the murine bone marrow-derived stromal cells.

PubMed

Agui, T; Yamada, T; Legros, G; Nakajima, T; Clark, M; Peschel, C; Matsumoto, K

1992-05-01

Atrial natriuretic peptide (ANP) receptors were identified on both murine bone marrow-derived stromal cell lines A-3 and ALC and primary cultured cells using [125I]ANP binding assays and Northern blot analyses. The binding of [125I] ANP to the stromal cells was rapid, saturable, and of high affinity. The dissociation constants between ANP and its receptors on these cells showed no difference among cell types, while maximal binding capacity values were different among cell types. Competitive inhibition of [125I]ANP binding with C-atrial natriuretic factor, specific for ANP clearance receptor (ANPR-C), revealed that most of [125I]ANP-binding sites corresponded to ANPR-C. Northern blotting data corroborated that bone marrow-derived stromal cells expressed ANPR-C. However, in ALC cells, ANP biological receptors (either ANPR-A or ANPR-B), the mol wt of which is approximately 130K, were detected, and cGMP was accumulated after stimulation with ANP. On the other hand, in another stromal cell clone, A-3 cells, the expression of biological receptor was not detected in the affinity cross-linking and competitive inhibition experiments using [125I]ANP. However, A-3 cells accumulated cGMP by responding to ANPR-B-specific ligand, C-type natriuretic peptide. These results suggest that ALC cells equally express ANPR-A and ANPR-B, while A-3 cells express ANPR-B dominantly. Although the physiological roles of these receptors in the bone marrow is still not resolved, ANP is expected to play a role in the regulation of stromal cell functions in bone marrow.

Compensatory functions and interdependency of the DNA-binding domain of BRCA2 with the BRCA1-PALB2-BRCA2 complex.

PubMed

Al Abo, Muthana; Dejsuphong, Donniphat; Hirota, Kouji; Yonetani, Yasukazu; Yamazoe, Mitsuyoshi; Kurumizaka, Hitoshi; Takeda, Shunichi

2014-02-01

BRCA1, BRCA2, and PALB2 are key players in cellular tolerance to chemotherapeutic agents, including camptothecin, cisplatin, and PARP inhibitor. The N-terminal segment of BRCA2 interacts with PALB2, thus contributing to the formation of the BRCA1-PALB2-BRCA2 complex. To understand the role played by BRCA2 in this complex, we deleted its N-terminal segment and generated BRCA2(Δ)(N) mutant cells. Although previous studies have suggested that BRCA1-PALB2 plays a role in the recruitment of BRCA2 to DNA-damage sites, BRCA2(Δ)(N) mutant cells displayed a considerably milder phenotype than did BRCA2(-/-) null-deficient cells. We hypothesized that the DNA-binding domain (DBD) of BRCA2 might compensate for a defect in BRCA2(ΔN) that prevented stable interaction with PALB2. To test this hypothesis, we disrupted the DBD of BRCA2 in wild-type and BRCA2(Δ)(N) cells. Remarkably, although the resulting BRCA2(Δ)(DBD) cells displayed a moderate phenotype, the BRCA2(Δ)(N+ΔDBD) cells displayed a very severe phenotype, as did the BRCA2(-/-) cells, suggesting that the N-terminal segment and the DBD play a substantially overlapping role in the functionality of BRCA2. We also showed that the formation of both the BRCA1-PALB2-BRCA2 complex and the DBD is required for efficient recruitment of BRCA2 to DNA-damage sites. Our study revealed the essential role played by both the BRCA1-PALB2-BRCA2 complex and the DBD in the functionality of BRCA2, as each can compensate for the other in the recruitment of BRCA2 to DNA-damage sites. This knowledge adds to our ability to accurately predict the efficacy of antimalignant therapies for patients carrying mutations in the BRCA2 gene.

Proline oxidase controls proline, glutamate, and glutamine cellular concentrations in a U87 glioblastoma cell line.

PubMed

Cappelletti, Pamela; Tallarita, Elena; Rabattoni, Valentina; Campomenosi, Paola; Sacchi, Silvia; Pollegioni, Loredano

2018-01-01

L-Proline is a multifunctional amino acid that plays an essential role in primary metabolism and physiological functions. Proline is oxidized to glutamate in the mitochondria and the FAD-containing enzyme proline oxidase (PO) catalyzes the first step in L-proline degradation pathway. Alterations in proline metabolism have been described in various human diseases, such as hyperprolinemia type I, velo-cardio-facial syndrome/Di George syndrome, schizophrenia and cancer. In particular, the mutation giving rise to the substitution Leu441Pro was identified in patients suffering of schizophrenia and hyperprolinemia type I. Here, we report on the expression of wild-type and L441P variants of human PO in a U87 glioblastoma human cell line in an attempt to assess their effect on glutamate metabolism. The subcellular localization of the flavoenzyme is not altered in the L441P variant, for which specific activity is halved compared to the wild-type PO. While this decrease in activity is significantly less than that previously proposed, an effect of the substitution on the enzyme stability is also apparent in our studies. At 24 hours of growth from transient transfection, the intracellular level of proline, glutamate, and glutamine is decreased in cells expressing the PO variants as compared to control U87 cells, reaching a similar figure at 72 h. On the other hand, the extracellular levels of the three selected amino acids show a similar time course for all clones. Furthermore, PO overexpression does not modify to a significant extent the expression of GLAST and GLT-1 glutamate transporters. Altogether, these results demonstrate that the proline pathway links cellular proline levels with those of glutamate and glutamine. On this side, PO might play a regulatory role in glutamatergic neurotransmission by affecting the cellular concentration of glutamate.

Modulation of human beta-defensin-1 (hBD-1) in plasmacytoid dendritic cells (PDC), monocytes, and epithelial cells by influenza virus, Herpes simplex virus, and Sendai virus and its possible role in innate immunity.

PubMed

Ryan, Lisa K; Dai, Jihong; Yin, Zhiwei; Megjugorac, Nicholas; Uhlhorn, Victoria; Yim, Sunghan; Schwartz, Kyell D; Abrahams, Joshua M; Diamond, Gill; Fitzgerald-Bocarsly, Patricia

2011-08-01

hBD comprise a family of antimicrobial peptides that plays a role in bridging the innate and adaptive immune responses to infection. The expression of hBD-2 increases upon stimulation of numerous cell types with LPS and proinflammatory cytokines. In contrast, hBD-1 remains constitutively expressed in most cells in spite of cytokine or LPS stimulation; however, its presence in human PDC suggests it plays a role in viral host defense. To examine this, we characterized the expression of hBD-1 in innate immune cells in response to viral challenge. PDC and monocytes increased production of hBD-1 peptide and mRNA as early as 2 h following infection of purified cells and PBMCs with PR8, HSV-1, and Sendai virus. However, treatment of primary NHBE cells with influenza resulted in a 50% decrease in hBD-1 mRNA levels, as measured by qRT-PCR at 3 h following infection. A similar inhibition occurred with HSV-1 challenge of human gingival epithelial cells. Studies with HSV-1 showed that replication occurred in epithelial cells but not in PDC. Together, these results suggest that hBD-1 may play a role in preventing viral replication in immune cells. To test this, we infected C57BL/6 WT mice and mBD-1((-/-)) mice with mouse-adapted HK18 (300 PFU/mouse). mBD-1((-/-)) mice lost weight earlier and died sooner than WT mice (P=0.0276), suggesting that BD-1 plays a role in early innate immune responses against influenza in vivo. However, lung virus titers were equal between the two mouse strains. Histopathology showed a greater inflammatory influx in the lungs of mBD-1((-/-)) mice at Day 3 postinfection compared with WT C57BL/6 mice. The results suggest that BD-1 protects mice from influenza pathogenesis with a mechanism other than inhibition of viral replication.

Bioelectric patterning during oogenesis: stage-specific distribution of membrane potentials, intracellular pH and ion-transport mechanisms in Drosophila ovarian follicles.

PubMed

Krüger, Julia; Bohrmann, Johannes

2015-01-16

Bioelectric phenomena have been found to exert influence on various developmental and regenerative processes. Little is known about their possible functions and the cellular mechanisms by which they might act during Drosophila oogenesis. In developing follicles, characteristic extracellular current patterns and membrane-potential changes in oocyte and nurse cells have been observed that partly depend on the exchange of protons, potassium ions and sodium ions. These bioelectric properties have been supposed to be related to various processes during oogenesis, e. g. pH-regulation, osmoregulation, cell communication, cell migration, cell proliferation, cell death, vitellogenesis and follicle growth. Analysing in detail the spatial distribution and activity of the relevant ion-transport mechanisms is expected to elucidate the roles that bioelectric phenomena play during oogenesis. To obtain an overview of bioelectric patterning along the longitudinal and transversal axes of the developing follicle, the spatial distributions of membrane potentials (Vmem), intracellular pH (pHi) and various membrane-channel proteins were studied systematically using fluorescent indicators, fluorescent inhibitors and antisera. During mid-vitellogenic stages 9 to 10B, characteristic, stage-specific Vmem-patterns in the follicle-cell epithelium as well as anteroposterior pHi-gradients in follicle cells and nurse cells were observed. Corresponding distribution patterns of proton pumps (V-ATPases), voltage-dependent L-type Ca(2+)-channels, amiloride-sensitive Na(+)-channels and Na(+),H(+)-exchangers (NHE) and gap-junction proteins (innexin 3) were detected. In particular, six morphologically distinguishable follicle-cell types are characterized on the bioelectric level by differences concerning Vmem and pHi as well as specific compositions of ion channels and carriers. Striking similarities between Vmem-patterns and activity patterns of voltage-dependent Ca(2+)-channels were found, suggesting a mechanism for transducing bioelectric signals into cellular responses. Moreover, gradients of electrical potential and pH were observed within single cells. Our data suggest that spatial patterning of Vmem, pHi and specific membrane-channel proteins results in bioelectric signals that are supposed to play important roles during oogenesis, e. g. by influencing spatial coordinates, regulating migration processes or modifying the cytoskeletal organization. Characteristic stage-specific changes of bioelectric activity in specialized cell types are correlated with various developmental processes.

The putative hydrolase YycJ (WalJ) affects the coordination of cell division with DNA replication in Bacillus subtilis and may play a conserved role in cell wall metabolism.

PubMed

Biller, Steven J; Wayne, Kyle J; Winkler, Malcolm E; Burkholder, William F

2011-02-01

Bacteria must accurately replicate and segregate their genetic information to ensure the production of viable daughter cells. The high fidelity of chromosome partitioning is achieved through mechanisms that coordinate cell division with DNA replication. We report that YycJ (WalJ), a predicted member of the metallo-β-lactamase superfamily found in most low-G+C Gram-positive bacteria, contributes to the fidelity of cell division in Bacillus subtilis. B. subtilis ΔwalJ (ΔwalJ(Bsu)) mutants divide over unsegregated chromosomes more frequently than wild-type cells, and this phenotype is exacerbated when DNA replication is inhibited. Two lines of evidence suggest that WalJ(Bsu) and its ortholog in the Gram-positive pathogen Streptococcus pneumoniae, WalJ(Spn) (VicX), play a role in cell wall metabolism: (i) strains of B. subtilis and S. pneumoniae lacking walJ exhibit increased sensitivity to a narrow spectrum of cephalosporin antibiotics, and (ii) reducing the expression of a two-component system that regulates genes involved in cell wall metabolism, WalRK (YycFG), renders walJ essential for growth in B. subtilis, as observed previously with S. pneumoniae. Together, these results suggest that the enzymatic activity of WalJ directly or indirectly affects cell wall metabolism and is required for accurate coordination of cell division with DNA replication.

BCL11B is frequently downregulated in HTLV-1-infected T-cells through Tax-mediated proteasomal degradation.

PubMed

Permatasari, Happy Kurnia; Nakahata, Shingo; Ichikawa, Tomonaga; Morishita, Kazuhiro

2017-08-26

Human T-cell leukemia virus type 1 (HTLV-1) is a causative agent of adult T-cell leukemia-lymphoma (ATLL). The HTLV-1-encoded protein Tax plays important roles in the proliferation of HTLV-1-infected T-cells by affecting cellular proteins. In this study, we showed that Tax transcriptionally and post-transcriptionally downregulates the expression of the tumor suppressor gene B-cell leukemia/lymphoma 11B (BCL11B), which encodes a lymphoid-related transcription factor. BCL11B expression was downregulated in HTLV-1-infected T-cell lines at the mRNA and protein levels, and forced expression of BCL11B suppressed the proliferation of these cells. The proteasomal inhibitor MG132 increased BCL11B expression in HTLV-1-infected cell lines, and colocalization of Tax with BCL11B was detected in the cytoplasm of HTLV-1-infected T-cells following MG132 treatment. shRNA knock-down of Tax expression also increased the expression of BCL11B in HTLV-1-infected cells. Moreover, we found that Tax physically binds to BCL11B protein and induces the polyubiquitination of BCL11B and proteasome-dependent degradation of BCL11B. Thus, inactivation of BCL11B by Tax protein may play an important role in the Tax-mediated leukemogenesis. Copyright © 2017 Elsevier Inc. All rights reserved.

Concerted evolution of body mass and cell size: similar patterns among species of birds (Galliformes) and mammals (Rodentia)

PubMed Central

Dragosz-Kluska, Dominika; Pis, Tomasz; Pawlik, Katarzyna; Kapustka, Filip; Kilarski, Wincenty M.; Kozłowski, Jan

2018-01-01

ABSTRACT Cell size plays a role in body size evolution and environmental adaptations. Addressing these roles, we studied body mass and cell size in Galliformes birds and Rodentia mammals, and collected published data on their genome sizes. In birds, we measured erythrocyte nuclei and basal metabolic rates (BMRs). In birds and mammals, larger species consistently evolved larger cells for five cell types (erythrocytes, enterocytes, chondrocytes, skin epithelial cells, and kidney proximal tubule cells) and evolved smaller hepatocytes. We found no evidence that cell size differences originated through genome size changes. We conclude that the organism-wide coordination of cell size changes might be an evolutionarily conservative characteristic, and the convergent evolutionary body size and cell size changes in Galliformes and Rodentia suggest the adaptive significance of cell size. Recent theory predicts that species evolving larger cells waste less energy on tissue maintenance but have reduced capacities to deliver oxygen to mitochondria and metabolize resources. Indeed, birds with larger size of the abovementioned cell types and smaller hepatocytes have evolved lower mass-specific BMRs. We propose that the inconsistent pattern in hepatocytes derives from the efficient delivery system to hepatocytes, combined with their intense involvement in supracellular function and anabolic activity. PMID:29540429

Normal and abnormal secretion by haemopoietic cells

PubMed Central

STINCHCOMBE, JANE C; GRIFFITHS, GILLIAN M

2001-01-01

The secretory lysosomes found in haemopoietic cells provide a very efficient mechanism for delivering the effector proteins of many immune cells in response to antigen recognition. Although secretion shows some similarities to the secretion of specialized granules in other secretory cell types, some aspects of secretory lysosome release appear to be unique to melanocytes and cells of the haemopoietic lineage. Mast cells and platelets have provided excellent models for studying secretion, but recent advances in characterizing the immunological synapse allow a very fine dissection of the secretory process in T lymphocytes. These studies show that secretory lysosomes are secreted from the centre of the talin ring at the synapse. Proper secretion requires a series of Rab and cytoskeletal elements which play critical roles in the specialized secretion of lysosomes in haemopoietic cells. PMID:11380687

Granulocyte-macrophage colony-stimulating factor induces the differentiation of murine erythroleukaemia cells into dendritic cells.

PubMed Central

Cao, X; Zhao, Y; Yu, Y; Wang, Y; Zhang, M; Zhang, W; Wang, J

1998-01-01

Dendritic cells (DC) are professional antigen-presenting cells (APC) within the immune system and antigen-pulsed DC can be used as an effective vaccine for active immunotherapy of cancer. Granulocyte-macrophage colony-stimulating factor (GM-CSF) plays an important role in the generation of DC. We previously showed that GM-CSF can induce murine erythroleukaemia cells (FBL-3) to differentiate into monocyte-like cells. To develop a new vaccinating method to stimulate the host immune response to leukaemia, we further investigate whether FBL-3 cells induced by GM-CSF can differentiate into DC in the present study. After being treated with GM-CSF, FBL-3 cells expressed high levels of 33D1 and NLDC-145, which are the specific markers of DC. The expression of MHC-II, B7-1, B7-2 and vascular cell adhesion molecule-1 (VCAM-1) was up-regulated markedly; the typical morphology of DC were also observed by electron microscopy. Functionally, the GM-CSF-induced FBL-3 cells could apparently stimulate the proliferation of naive allogeneic and autologous T lymphocytes and induce the generation of specific CTL more efficiently than the wild-type FBL-3 cells. Mice immunized with GM-CSF-induced FBL-3 cells could resist the subsequent challenge with the wild-type FBL-3 cells. Collectively, these data indicate that GM-CSF differentiates murine erythroleukaemia cells into DC phenotypically, morphologically and functionally. FBL-3-derived DC can be used as a new type of vaccine. Our results may have important implications for the immunotherapy of leukaemia. Images Figure 3 Figure 4 PMID:9767469

The Drosophila ovarian and testis stem cell niches: similar somatic stem cells and signals.

PubMed

Decotto, Eva; Spradling, Allan C

2005-10-01

The stem cell niches at the apex of Drosophila ovaries and testes have been viewed as distinct in two major respects. While both contain germline stem cells, the testis niche also contains "cyst progenitor" stem cells, which divide to produce somatic cells that encase developing germ cells. Moreover, while both niches utilize BMP signaling, the testis niche requires a key JAK/STAT signal. We now show, by lineage marking, that the ovarian niche also contains a second type of stem cell. These "escort stem cells" morphologically resemble testis cyst progenitor cells and their daughters encase developing cysts before undergoing apoptosis at the time of follicle formation. In addition, we show that JAK/STAT signaling also plays a critical role in ovarian niche function, and acts within escort cells. These observations reveal striking similarities in the stem cell niches of male and female gonads, and suggest that they are largely governed by common mechanisms.

NK cells contribute to persistent airway inflammation and AHR during the later stage of RSV infection in mice.

PubMed

Long, Xiaoru; Xie, Jun; Zhao, Keting; Li, Wei; Tang, Wei; Chen, Sisi; Zang, Na; Ren, Luo; Deng, Yu; Xie, Xiaohong; Wang, Lijia; Fu, Zhou; Liu, Enmei

2016-10-01

RSV can lead to persistent airway inflammation and AHR and is intimately associated with childhood recurrent wheezing and asthma, but the underlying mechanisms remain unclear. There are high numbers of NK cells in the lung, which not only play important roles in the acute stage of RSV infection, but also are pivotal in regulating the pathogenesis of asthma. Therefore, in this study, we assumed that NK cells might contribute to persistent airway disease during the later stage of RSV infection. Mice were killed at serial time points after RSV infection to collect samples. Leukocytes in bronchoalveolar lavage fluid (BALF) were counted, lung histopathology was examined, and airway hyperresponsiveness (AHR) was measured by whole-body plethysmography. Cytokines were detected by ELISA, and NK cells were determined by flow cytometry. Rabbit anti-mouse asialo-GM-1 antibodies and resveratrol were used to deplete or suppress NK cells. Inflammatory cells in BALF, lung tissue damage and AHR were persistent for 60 days post-RSV infection. Type 2 cytokines and NK cells were significantly increased during the later stage of infection. When NK cells were decreased by the antibodies or resveratrol, type 2 cytokines, the persistent airway inflammation and AHR were all markedly reduced. NK cells can contribute to the RSV-associated persistent airway inflammation and AHR at least partially by promoting type 2 cytokines. Therefore, therapeutic targeting of NK cells may provide a novel approach to alleviating the recurrent wheezing subsequent to RSV infection.

Contribution of Invariant Natural Killer T Cells to Skin Wound Healing.

PubMed

Tanno, Hiromasa; Kawakami, Kazuyoshi; Ritsu, Masae; Kanno, Emi; Suzuki, Aiko; Kamimatsuno, Rina; Takagi, Naoyuki; Miyasaka, Tomomitsu; Ishii, Keiko; Imai, Yoshimichi; Maruyama, Ryoko; Tachi, Masahiro

2015-12-01

In the present study, we determined the contribution of invariant natural killer T (iNKT) cells to the skin wound healing process. In iNKT cell-deficient (Jα18KO) mice lacking iNKT cells, wound closure was significantly delayed compared with wild-type mice. Collagen deposition, expression of α-smooth muscle actin and CD31, and wound breaking strength were significantly attenuated in Jα18KO mice. The adoptive transfer of liver mononuclear cells from wild-type but not from Jα18KO or interferon (IFN)-γ gene-disrupted (IFN-γKO) mice resulted in the reversal of this impaired wound healing in Jα18KO mice. IFN-γ expression was induced in the wounded tissues, which was significantly decreased at 6, 12, and 24 hours, but increased on day 3 after wounding in Jα18KO mice. The main source of the late-phase IFN-γ production in Jα18KO mice were neutrophils rather than NK cells and T cells. Administration of α-galactosylceramide, an activator of iNKT cells, resulted in the acceleration of wound healing on day 3 in wild-type mice. This effect was not observed in IFN-γKO mice. These results indicate that iNKT cells play important roles in wound healing. The iNKT cell-induced IFN-γ production may regulate the wound healing process in the early phase. Copyright © 2015 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

The specific role of plastidial glycolysis in photosynthetic and heterotrophic cells under scrutiny through the study of glyceraldehyde-3-phosphate dehydrogenase.

PubMed

Anoman, Armand Djoro; Flores-Tornero, María; Rosa-Telléz, Sara; Muñoz-Bertomeu, Jesús; Segura, Juan; Ros, Roc

2016-01-01

The cellular compartmentalization of metabolic processes is an important feature in plants where the same pathways could be simultaneously active in different compartments. Plant glycolysis occurs in the cytosol and plastids of green and non-green cells in which the requirements of energy and precursors may be completely different. Because of this, the relevance of plastidial glycolysis could be very different depending on the cell type. In the associated study, we investigated the function of plastidial glycolysis in photosynthetic and heterotrophic cells by specifically driving the expression of plastidial glyceraldehyde-3-phosphate dehydrogenase (GAPCp) in a glyceraldehyde-3-phosphate dehydrogenase double mutant background (gapcp1gapcp2). We showed that GAPCp is not functionally significant in photosynthetic cells, while it plays a crucial function in heterotrophic cells. We also showed that (i) GAPCp activity expression in root tips is necessary for primary root growth, (ii) its expression in heterotrophic cells of aerial parts and roots is necessary for plant growth and development, and (iii) GAPCp is an important metabolic connector of carbon and nitrogen metabolism through the phosphorylated pathway of serine biosynthesis (PPSB). We discuss here the role that this pathway could play in the control of plant growth and development.

A Tumor Suppressor Gene Product, Platelet-Derived Growth Factor Receptor-Like Protein Controls Chondrocyte Proliferation and Differentiation.

PubMed

Kawata, Kazumi; Kubota, Satoshi; Eguchi, Takanori; Aoyama, Eriko; Moritani, Norifumi H; Oka, Morihiko; Kawaki, Harumi; Takigawa, Masaharu

2017-11-01

The platelet-derived growth factor receptor-like (PDGFRL) gene is regarded as a tumor suppressor gene. However, nothing is known about the molecular function of PDGFRL. In this study, we initially clarified its function in chondrocytes. Among all cell lines examined, the PDGFRL mRNA level was the highest in chondrocytic HCS-2/8 cells. Interestingly, the proliferation of chondrocytic HCS-2/8 cells was promoted by PDGFRL overexpression, whereas that of the breast cancer-derived MDA-MB-231 cells was inhibited. Of note, in PDGFRL-overexpressing HCS-2/8 cells, the expression of chondrocyte differentiation marker genes, SOX9, ACAN, COL2A1, COL10A1, and ALP, was decreased. Moreover, we confirmed the expression of PDGFRL mRNA in normal cartilage tissue and chondrocytes. Eventually, the expression of PDGFRL mRNA in condrocytes except in the case of hypertrophic chondrocytes was demonstrated in vivo and in vitro. These findings suggest that PDGFRL plays the different roles, depending upon cell types. Particularly, in chondrocytes, PDGFRL may play a new and important role which is distinct from the function previously reported. J. Cell. Biochem. 118: 4033-4044, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Role of claudin species-specific dynamics in reconstitution and remodeling of the zonula occludens.

PubMed

Yamazaki, Yuji; Tokumasu, Reitaro; Kimura, Hiroshi; Tsukita, Sachiko

2011-05-01

Tight-junction strands, which are organized into the beltlike cell-cell adhesive structure called the zonula occludens (TJ), create the paracellular permselective barrier in epithelial cells. The TJ is constructed on the basis of the zonula adherens (AJ) by polymerized claudins in a process mediated by ZO-1/2, but whether the 24 individual claudin family members play different roles at the TJ is unclear. Here we established a cell system for examining the polymerization of individual claudins in the presence of ZO-1/2 using an epithelial-like cell line, SF7, which lacked endogenous TJs and expressed no claudin but claudin-12 in immunofluorescence and real-time PCR assays. In stable SF7-derived lines, exogenous claudin-7, -14, or -19, but no other claudins, individually reconstituted TJs, each with a distinct TJ-strand pattern, as revealed by freeze-fracture analyses. Fluorescence recovery after photobleaching (FRAP) analyses of the claudin dynamics in these and other epithelial cells suggested that slow FRAP-recovery dynamics of claudins play a critical role in regulating their polymerization around AJs, which are loosely coupled with ZO-1/2, to form TJs. Furthermore, the distinct claudin stabilities in different cell types may help to understand how TJs regulate paracellular permeability by altering the paracellular flux and the paracellular ion permeability.

The type III secretion system is involved in Escherichia coli K1 interactions with Acanthamoeba.

PubMed

Siddiqui, Ruqaiyyah; Malik, Huma; Sagheer, Mehwish; Jung, Suk-Yul; Khan, Naveed Ahmed

2011-08-01

The type III secretion system among Gram-negative bacteria is known to deliver effectors into host cell to interfere with host cellular processes. The type III secretion system in Yersina, Pseudomonas and Enterohemorrhagic Escherichia coli have been well documented to be involved in the bacterial pathogenicity. The existence of type III secretion system has been demonstrated in neuropathogenic E. coli K1 strains. Here, it is observed that the deletion mutant of type III secretion system in E. coli strain EC10 exhibited defects in the invasion and intracellular survival in Acanthamoeba castellanii (a keratitis isolate) compared to its parent strain. Next, it was determined whether type III secretion system plays a role in E. coli K1 survival inside Acanthamoeba during the encystment process. Using encystment assays, our findings revealed that the type III secretion system-deletion mutant exhibited significantly reduced survival inside Acanthamoeba cysts compared with its parent strain, EC10 (P<0.01). This is the first demonstration that the type III secretion system plays an important role in E. coli interactions with Acanthamoeba. A complete understanding of how amoebae harbor bacterial pathogens will help design strategies against E. coli transmission to the susceptible hosts. Copyright © 2011 Elsevier Inc. All rights reserved.

Inactivation of the Gastrokine 1 gene in gastric adenomas and carcinomas.

PubMed

Yoon, Jung Hwan; Song, Jae Hwi; Zhang, Cao; Jin, Meishan; Kang, Young Hwi; Nam, Suk Woo; Lee, Jung Young; Park, Won Sang

2011-04-01

Gastrokine 1 (GKN1) plays a role in the gastric mucosal defence mechanism and may be a gastric tumour suppressor. We have investigated whether inactivation of the GKN1 gene is involved in the development and/or progression of gastric cancers. GKN1 protein expression was examined in gastric adenomas and cancer and we also analysed GKN1 mutation and epigenetic alteration, DNA copy number change and mRNA transcript expression. The effect of GKN1 on cell proliferation and death was examined in wild-type GKN1-transfected AGS gastric cancer cells. Reduced or loss of GKN1 expression was detected in 36 (90%) and 170 (89.5%) of 40 adenomas and 190 gastric cancers, respectively. Statistically, there was no significant relationship between altered expression of GKN1 protein and clinicopathological parameters, including depth of invasion, location and lymph node metastasis (χ(2) test, p > 0.05). In western blot analysis, absence or reduced expression was found in 21 (84.0%) of 25 gastric carcinomas. No mutation was detected in gastric tumours, and hypermethylation of GKN1 gene was found in two tumours. DNA copy number and mRNA transcript of GKN1 were significantly decreased in gastric cancers. In functional analysis, AGS gastric cancer cells transfected with GKN1 wild-type showed marked inhibition of cell proliferation and induction of cell death. These data suggest that inactivation of the GKN1 gene may play an important role in the development of sporadic gastric cancers, as an early event. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Adenovirus-mediated Wnt5a expression inhibits the telogen-to-anagen transition of hair follicles in mice.

PubMed

Xing, Yi-Zhan; Wang, Rui-Min; Yang, Ke; Guo, Hai-Ying; Deng, Fang; Li, Yu-Hong; Ye, Ji-Xing; He, Long; Lian, Xiao-Hua; Yang, Tian

2013-01-01

The canonical Wnt/β-catenin pathway plays an important role in hair cycle induction. Wnt5a is a non-canonical Wnt family member that generally antagonizes canonical Wnt signaling in other systems. In hair follicles, Wnt5a and canonical Wnt are both expressed in cells in the telogen stage. Wnt5a has been shown to be critical for controlling hair cell fate. However, the role that Wnt5a plays in the transition from the telogen to anagen stage is unknown. In this study, using whole-mount in situ hybridization, we show that Wnt5a is produced by several other cell types, excluding dermal papilla cells, throughout the hair cycle. For example, Wnt5a is expressed in bulge and secondary hair germ cells in the telogen stage. Our studies focused on the depilated 8-week-old mouse as a synchronized model of hair growth. Interestingly, overexpression of adenovirus Wnt5a in the dorsal skin of mice led to the elongation of the telogen stage and inhibition of the initiation of the anagen stage. However, following an extended period of time, four pelage hair types grew from hairless skin that was induced by Wnt5a, and the structure of these new hair shafts was normal. Using microarray analysis and quantitative arrays, we showed that the expression of β-catenin and some target genes of canonical Wnt signaling decreased after Wnt5a treatment. These data demonstrate that Wnt5a may inhibit the telogen stage to maintain a quiescent state of the hair follicle.

Emerging roles of basophils in allergic inflammation.

PubMed

Miyake, Kensuke; Karasuyama, Hajime

2017-07-01

Basophils have long been neglected in immunological studies because they were regarded as only minor relatives of mast cells. However, recent advances in analytical tools for basophils have clarified the non-redundant roles of basophils in allergic inflammation. Basophils play crucial roles in both IgE-dependent and -independent allergic inflammation, through their migration to the site of inflammation and secretion of various mediators, including cytokines, chemokines, and proteases. Basophils are known to produce large amounts of IL-4 in response to various stimuli. Basophil-derived IL-4 has recently been shown to play versatile roles in allergic inflammation by acting on various cell types, including macrophages, innate lymphoid cells, fibroblasts, and endothelial cells. Basophil-derived serine proteases are also crucial for the aggravation of allergic inflammation. Moreover, recent reports suggest the roles of basophils in modulating adaptive immune responses, particularly in the induction of Th2 differentiation and enhancement of humoral memory responses. In this review, we will discuss recent advances in understanding the roles of basophils in allergic inflammation. Copyright © 2017 Japanese Society of Allergology. Production and hosting by Elsevier B.V. All rights reserved.

The Role of the Reactive Oxygen Species and Oxidative Stress in the Pathomechanism of the Age-Related Ocular Diseases and Other Pathologies of the Anterior and Posterior Eye Segments in Adults

PubMed Central

Nita, Małgorzata; Grzybowski, Andrzej

2016-01-01

The reactive oxygen species (ROS) form under normal physiological conditions and may have both beneficial and harmful role. We search the literature and current knowledge in the aspect of ROS participation in the pathogenesis of anterior and posterior eye segment diseases in adults. ROS take part in the pathogenesis of keratoconus, Fuchs endothelial corneal dystrophy, and granular corneal dystrophy type 2, stimulating apoptosis of corneal cells. ROS play a role in the pathogenesis of glaucoma stimulating apoptotic and inflammatory pathways on the level of the trabecular meshwork and promoting retinal ganglion cells apoptosis and glial dysfunction in the posterior eye segment. ROS play a role in the pathogenesis of Leber's hereditary optic neuropathy and traumatic optic neuropathy. ROS induce apoptosis of human lens epithelial cells. ROS promote apoptosis of vascular and neuronal cells and stimulate inflammation and pathological angiogenesis in the course of diabetic retinopathy. ROS are associated with the pathophysiological parainflammation and autophagy process in the course of the age-related macular degeneration. PMID:26881021

Infiltration of Matrix-Non-producers Weakens the Salmonella Biofilm and Impairs Its Antimicrobial Tolerance and Pathogenicity.

PubMed

Srinandan, Chakravarthy S; Elango, Monalisha; Gnanadhas, Divya P; Chakravortty, Dipshikha

2015-01-01

Bacterial biofilms display a collective lifestyle, wherein the cells secrete extracellular polymeric substances (EPS) that helps in adhesion, aggregation, stability, and to protect the bacteria from antimicrobials. We asked whether the EPS could act as a public good for the biofilm and observed that infiltration of cells that do not produce matrix components weakened the biofilm of Salmonella enterica serovar Typhimurium. EPS production was costly for the producing cells, as indicated by a significant reduction in the fitness of wild type (WT) cells during competitive planktonic growth relative to the non-producers. Infiltration frequency of non-producers in the biofilm showed a concomitant decrease in overall productivity. It was apparent in the confocal images that the non-producing cells benefit from the EPS produced by the Wild Type (WT) to stay in the biofilm. The biofilm containing non-producing cells were more significantly susceptible to sodium hypochlorite and ciprofloxacin treatment than the WT biofilm. Biofilm infiltrated with non-producers delayed the pathogenesis, as tested in a murine model. The cell types were spatially assorted, with non-producers being edged out in the biofilm. However, cellulose was found to act as a barrier to keep the non-producers away from the WT microcolony. Our results show that the infiltration of non-cooperating cell types can substantially weaken the biofilm making it vulnerable to antibacterials and delay their pathogenesis. Cellulose, a component of EPS, was shown to play a pivotal role of acting as the main public good, and to edge-out the non-producers away from the cooperating microcolony.

Antiproliferative and Apoptotic Effect of Dendrosomal Curcumin Nanoformulation in P53 Mutant and Wide-Type Cancer Cell Lines.

PubMed

Montazeri, Maryam; Pilehvar-Soltanahmadi, Younes; Mohaghegh, Mina; Panahi, Alireza; Khodi, Samaneh; Zarghami, Nosratollah; Sadeghizadeh, Majid

2017-01-01

The aim of this paper is to investigate the effect of dendrosomal curcumin (DNC) on the expression of p53 in both p53 mutant cell lines SKBR3/SW480 and p53 wild-type MCF7/HCT116 in both RNA and protein levels. Curcumin, derived from Curcumin longa, is recently considered in cancer related researches for its cell growth inhibition properties. p53 is a common tumor-suppressor gene involved in cancers and its mutation not only inhibits tumor suppressor activity but also promotes oncogenic activity. Here, p53 mutant/Wild-type cells were employed to study the toxicity of DNC using MTT assay, Flow cytometry and Annexin-V, Real-time PCR and Western blot were used to analyze p53, BAX, Bcl-2, p21 and Noxa changes after treatment. During the time, DNC increased the SubG1 cells and decreased G1, S and G2/M cells, early apoptosis also indicated the inhibition of cell growth in early phase. Real-Time PCR assay showed an increased mRNA of BAX, Noxa and p21 during the time with decreased Bcl-2. The expression of p53 mutant decreased in SKBR3/SW480, and the expression of p53 wild-type increased in MCF7/HCT116. Consequently, p53 plays an important role in mediating the survival by DNC, which can prevent tumor cell growth by modulating the expression of genes involved in apoptosis and proliferation. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

The role of natural killer cells in autoimmune blistering diseases.

PubMed

Zakka, L R; Fradkov, E; Keskin, D B; Tabansky, I; Stern, J N H; Ahmed, A R

2012-02-01

The major focus of this paper is to describe and evaluate current information on the role of natural killer cells (NK cells) in the pathogenesis of blistering diseases. Until now, only pemphigus vulgaris (PV) has been studied. One co-culture study demonstrated that CD4+ T cells from the peripheral blood or perilesional skin of patients with active disease proliferate and secrete cytokines in the presence of major histocompatibility class II-expressing NK cells loaded with antigenic desmoglein self-peptides. Another study showed that NK cells can contribute to a T helper type 2-biased immune response through impaired interleukins (IL)-12 signaling and upregulation of IL, IL-10 and IL-5. Although significant data on other blistering diseases are unavailable at present, some studies implicate NK cells in disease progression. For instance, information on the role of NK cells in psoriasis and their production of tumor necrosis factor-α (TNF-α) will be provided since several TNF-α-inhibitors are used in its treatment. Studies on alopecia areata are also included in this paper because NK cells seem to play a key role in its pathogenesis. This review highlights the potential importance of NK cells and NKT cells as members of the large repertoire of cells and soluble mediators that play a critical role in pathogenesis of blistering diseases and other autoimmune diseases involving the skin. Therefore, the authors advocate a greater focus and interest on the study of the interaction of NK cells and the skin.

Genome-edited human stem cell-derived beta cells: a powerful tool for drilling down on type 2 diabetes GWAS biology.

PubMed

Beer, Nicola L; Gloyn, Anna L

2016-01-01

Type 2 diabetes (T2D) is a disease of pandemic proportions, one defined by a complex aetiological mix of genetic, epigenetic, environmental, and lifestyle risk factors. Whilst the last decade of T2D genetic research has identified more than 100 loci showing strong statistical association with disease susceptibility, our inability to capitalise upon these signals reflects, in part, a lack of appropriate human cell models for study. This review discusses the impact of two complementary, state-of-the-art technologies on T2D genetic research: the generation of stem cell-derived, endocrine pancreas-lineage cells and the editing of their genomes. Such models facilitate investigation of diabetes-associated genomic perturbations in a physiologically representative cell context and allow the role of both developmental and adult islet dysfunction in T2D pathogenesis to be investigated. Accordingly, we interrogate the role that patient-derived induced pluripotent stem cell models are playing in understanding cellular dysfunction in monogenic diabetes, and how site-specific nucleases such as the clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 system are helping to confirm genes crucial to human endocrine pancreas development. We also highlight the novel biology gleaned in the absence of patient lines, including an ability to model the whole phenotypic spectrum of diabetes phenotypes occurring both in utero and in adult cells, interrogating the non-coding 'islet regulome' for disease-causing perturbations, and understanding the role of other islet cell types in aberrant glycaemia. This article aims to reinforce the importance of investigating T2D signals in cell models reflecting appropriate species, genomic context, developmental time point, and tissue type.

Expression of the synaptic exocytosis-regulating molecule complexin 2 in taste buds and its participation in peripheral taste transduction.

PubMed

Kurokawa, Azusa; Narukawa, Masataka; Ohmoto, Makoto; Yoshimoto, Joto; Abe, Keiko; Misaka, Takumi

2015-06-01

Taste information from type III taste cells to gustatory neurons is thought to be transmitted via synapses. However, the molecular mechanisms underlying taste transduction through this pathway have not been fully elucidated. In this study, to identify molecules that participate in synaptic taste transduction, we investigated whether complexins (Cplxs), which play roles in regulating membrane fusion in synaptic vesicle exocytosis, were expressed in taste bud cells. Among four Cplx isoforms, strong expression of Cplx2 mRNA was detected in type III taste cells. To investigate the function of CPLX2 in taste transduction, we observed taste responses in CPLX2-knockout mice. When assessed with electrophysiological and behavioral assays, taste responses to some sour stimuli in CPLX2-knockout mice were significantly lower than those in wild-type mice. These results suggested that CPLX2 participated in synaptic taste transduction from type III taste cells to gustatory neurons. A part of taste information is thought to be transmitted via synapses. However, the molecular mechanisms have not been fully elucidated. To identify molecules that participate in synaptic taste transduction, we investigated complexins (Cplxs) expression in taste bud cells. Strong expression of Cplx2 mRNA was detected in taste bud cells. Furthermore, taste responses to some sour stimuli in CPLX2- knockout mice were significantly lower than those in wild-type mice. These suggested that CPLX2 participated in synaptic taste transduction. © 2015 The Authors. Journal of Neurochemistry published by John Wiley & Sons Ltd on behalf of The International Society for Neurochemistry.

Ironing out the role of the cyclin-dependent kinase inhibitor, p21 in cancer: Novel iron chelating agents to target p21 expression and activity.

PubMed

Moussa, Rayan S; Park, Kyung Chan; Kovacevic, Zaklina; Richardson, Des R

2018-03-20

Iron (Fe) has become an important target for the development of anti-cancer therapeutics with a number of Fe chelators entering human clinical trials for advanced and resistant cancer. An important aspect of the activity of these compounds is their multiple molecular targets, including those that play roles in arresting the cell cycle, such as the cyclin-dependent kinase inhibitor, p21. At present, the exact mechanism by which Fe chelators regulate p21 expression remains unclear. However, recent studies indicate the ability of chelators to up-regulate p21 at the mRNA level was dependent on the chelator and cell-type investigated. Analysis of the p21 promoter identified that the Sp1-3-binding site played a significant role in the activation of p21 transcription by Fe chelators. Furthermore, there was increased Sp1/ER-α and Sp1/c-Jun complex formation in melanoma cells, suggesting these complexes were involved in p21 promoter activation. Elucidating the mechanisms involved in the regulation of p21 expression in response to Fe chelator treatment in neoplastic cells will further clarify how these agents achieve their anti-tumor activity. It will also enhance our understanding of the complex roles p21 may play in neoplastic cells and lead to the development of more effective and specific anti-cancer therapies. Copyright © 2018 Elsevier Inc. All rights reserved.

Regulation of Neuronal Cav3.1 Channels by Cyclin-Dependent Kinase 5 (Cdk5)

PubMed Central

González-Ramírez, Ricardo; González-Billault, Christian; Felix, Ricardo

2015-01-01

Low voltage-activated (LVA) T-type Ca2+ channels activate in response to subthreshold membrane depolarizations and therefore represent an important source of Ca2+ influx near the resting membrane potential. In neurons, these proteins significantly contribute to control relevant physiological processes including neuronal excitability, pacemaking and post-inhibitory rebound burst firing. Three subtypes of T-type channels (Cav3.1 to Cav3.3) have been identified, and using functional expression of recombinant channels diverse studies have validated the notion that T-type Ca2+ channels can be modulated by various endogenous ligands as well as by second messenger pathways. In this context, the present study reveals a previously unrecognized role for cyclin-dependent kinase 5 (Cdk5) in the regulation of native T-type channels in N1E-115 neuroblastoma cells, as well as recombinant Cav3.1channels heterologously expressed in HEK-293 cells. Cdk5 and its co-activators play critical roles in the regulation of neuronal differentiation, cortical lamination, neuronal cell migration and axon outgrowth. Our results show that overexpression of Cdk5 causes a significant increase in whole cell patch clamp currents through T-type channels in N1E-115 cells, while siRNA knockdown of Cdk5 greatly reduced these currents. Consistent with this, overexpression of Cdk5 in HEK-293 cells stably expressing Cav3.1channels upregulates macroscopic currents. Furthermore, using site-directed mutagenesis we identified a major phosphorylation site at serine 2234 within the C-terminal region of the Cav3.1subunit. These results highlight a novel role for Cdk5 in the regulation of T-type Ca2+ channels. PMID:25760945

Regulation of neuronal cav3.1 channels by cyclin-dependent kinase 5 (Cdk5).

PubMed

Calderón-Rivera, Aida; Sandoval, Alejandro; González-Ramírez, Ricardo; González-Billault, Christian; Felix, Ricardo

2015-01-01

Low voltage-activated (LVA) T-type Ca2+ channels activate in response to subthreshold membrane depolarizations and therefore represent an important source of Ca2+ influx near the resting membrane potential. In neurons, these proteins significantly contribute to control relevant physiological processes including neuronal excitability, pacemaking and post-inhibitory rebound burst firing. Three subtypes of T-type channels (Cav3.1 to Cav3.3) have been identified, and using functional expression of recombinant channels diverse studies have validated the notion that T-type Ca2+ channels can be modulated by various endogenous ligands as well as by second messenger pathways. In this context, the present study reveals a previously unrecognized role for cyclin-dependent kinase 5 (Cdk5) in the regulation of native T-type channels in N1E-115 neuroblastoma cells, as well as recombinant Cav3.1channels heterologously expressed in HEK-293 cells. Cdk5 and its co-activators play critical roles in the regulation of neuronal differentiation, cortical lamination, neuronal cell migration and axon outgrowth. Our results show that overexpression of Cdk5 causes a significant increase in whole cell patch clamp currents through T-type channels in N1E-115 cells, while siRNA knockdown of Cdk5 greatly reduced these currents. Consistent with this, overexpression of Cdk5 in HEK-293 cells stably expressing Cav3.1channels upregulates macroscopic currents. Furthermore, using site-directed mutagenesis we identified a major phosphorylation site at serine 2234 within the C-terminal region of the Cav3.1subunit. These results highlight a novel role for Cdk5 in the regulation of T-type Ca2+ channels.

InvS Coordinates Expression of PrgH and FimZ and Is Required for Invasion of Epithelial Cells by Salmonella enterica serovar Typhimurium

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

Wang, Lu; Cai, Xia; Wu, Shuyan

ABSTRACT Deep sequencing has revolutionized our understanding of the bacterial RNA world and has facilitated the identification of 280 small RNAs (sRNAs) inSalmonella. Despite the suspicions that sRNAs may play important roles inSalmonellapathogenesis, the functions of most sRNAs remain unknown. To advance our understanding of RNA biology inSalmonellavirulence, we searched for sRNAs required for bacterial invasion into nonphagocytic cells. After screening 75 sRNAs, we discovered that the ablation of InvS caused a significant decrease ofSalmonellainvasion into epithelial cells. A proteomic analysis showed that InvS modulated the levels of several type III secretedSalmonellaproteins. The level of PrgH, a type III secretionmore » apparatus protein, was significantly lower in the absence of InvS, consistent with the known roles of PrgH in effector secretion and bacterial invasion. We discovered that InvS modulatesfimZexpression and hence flagellar gene expression and motility. We propose that InvS coordinates the increase of PrgH and decrease in FimZ that promote efficientSalmonellainvasion into nonphagocytic cells. IMPORTANCESalmonellosis continues to be the most common foodborne infection reported by the CDC in the United States. Central toSalmonellapathogenesis is the ability to invade nonphagocytic cells and to replicate inside host cells. Invasion genes are known to be regulated by protein transcriptional networks, but little is known about the role played by small RNAs (sRNAs) in this process. We have identified a novel sRNA, InvS, that is involved inSalmonellainvasion. Our result will likely provide an opportunity to better understand the fundamental question of howSalmonellaregulates invasion gene expression and may inform strategies for therapeutic intervention.« less

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.

IFN-{gamma} sensitizes MIN6N8 insulinoma cells to TNF-{alpha}-induced apoptosis by inhibiting NF-{kappa}B-mediated XIAP upregulation

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

Kim, Hun Sik; Kim, Sunshin; Lee, Myung-Shik

2005-10-28

Although X-linked inhibitor of apoptosis protein (XIAP) is an important intracellular suppressor of apoptosis in a variety of cell types, its role in cytokine-induced pancreatic {beta}-cell apoptosis remains unclear. Here, we found that: (i) XIAP level was inversely correlated with tumor necrosis factor (TNF)-{alpha}-induced apoptosis in MIN6N8 insulinoma cells; (ii) adenoviral XIAP overexpression abrogated the TNF-{alpha}-induced apoptosis through inhibition of caspase activity; (iii) downregulation of XIAP by antisense oligonucleotide or Smac peptide sensitized MIN6N8 cells to TNF-{alpha}-induced apoptosis; (iv) XIAP expression was induced by TNF-{alpha} through a nuclear factor-{kappa}B (NF-{kappa}B)-dependent pathway, and interferon (IFN)-{gamma} prevented such an induction in amore » manner independent of NF-{kappa}B, which presents a potential mechanism underlying cytotoxic IFN-{gamma}/TNF-{alpha} synergism. Taken together, our results suggest that XIAP is an important modulator of TNF-{alpha}-induced apoptosis of MIN6N8 cells, and XIAP regulation in pancreatic {beta}-cells might play an important role in pancreatic {beta}-cell apoptosis and in the pathogenesis of type 1 diabetes.« less

Fluoride Induces Apoptosis in Mammalian Cells: In Vitro and In Vivo Studies.

PubMed

Ribeiro, Daniel Araki; Cardoso, Caroline Margonato; Yujra, Veronica Quispe; DE Barros Viana, Milena; Aguiar, Odair; Pisani, Luciana Pellegrini; Oshima, Celina Tizuko Fujiyama

2017-09-01

Apoptosis is genetically programmed cell death, an irreversible process of cell senescence with characteristic features different from other cellular mechanisms of death such as necrosis. In the last years, apoptosis has been extensively studied in the scientific literature, because it has been established that apoptosis plays a crucial role following the time course of chronic degenerative diseases, such as cancer. Thus, several researchers have strugged to detect what chemical agents are able to inter fere with the apoptotic process. Thus, the purpose of this literature review is to assess if fluoride induces apoptosis in mammalian cells using in vivo and in vitro test systems. Certain mammalian cell types such as oral cells, blood and brain were exetensively investigated; the results showed that fluoride is able to induce apoptosis in both intrinsinc and extrinsic pathways. Moreover, other cells types have been poorly investigated such as bone, kidney and reproductive cells with conflicting results so far. Therefore, this area needs further investigation for the safety of human populations exposed to fluoride in a chronic way, as for example in developing countries. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

The role of metallothionein in oncogenesis and cancer treatment.

PubMed

Bizoń, Anna; Jędryczko, Kinga; Milnerowicz, Halina

2017-02-14

Metallothionein is cysteine-rich low molecular mass protein. The involvement of MT in many physiological and pathophysiological processes such as apoptosis, proliferation, angiogenesis, and the detoxification of heavy metals suggested participation of this protein in carcinogenesis and tumor therapy. Depending on the type of tissue and classification of carcinoma various it was observed relation between MT expression and tumor type, stage, grade, poor prognosis and body resistance to radiotherapy and chemotherapy. MT in tumor cell plays important role in defense mechanism against the effect of radiation by inhibiting the processes that lead to the apoptosis. A number of studies have shown an increased expression of MT in various human tumors of larynx, pancreas, kidney, uterus and breast, whereas lower MT expression was detected in liver tumors. Variable MT expression was detected in case of thyroid, prostate, lung, stomach and central nervous system tumors. Also MT plays crucial role in the cytostatics treatment. MT can bind cis-platinum compounds and removes them from the cells, which may lead to multidrug resistance. However, the same functions of MT protect against the negative effects of chemotherapeutic treatment. It is especially important in case of heart cells. Analysis of MT expression in tumor cells may be useful in choosing method of treatment. It is difficult to determine whether increased expression of MT is only a inducing factor of the development of the carcinogenesis, its malignances and multidrug resistance, or it is a factor inhibiting the induction and development of cancer.

Cell life and death in the anterior pituitary gland: role of oestrogens.

PubMed

Seilicovich, A

2010-07-01

Apoptotic processes play an important role in the maintenance of cell numbers in the anterior pituitary gland during physiological endocrine events. In this review, we summarise the regulation of apoptosis of anterior pituitary cells, particularly lactotrophs, somatotrophs and gonadotrophs, and analyse the possible mechanisms involved in oestrogen-induced apoptosis in anterior pituitary cells. Oestrogens exert apoptotic actions in several cell types and act as modulators of pituitary cell renewal, sensitising cells to both mitogenic and apoptotic signals. Local synthesis of growth factors and cytokines induced by oestradiol as well as changes in phenotypic features that enhance the responsiveness of anterior pituitary cells to pro-apoptotic factors may account for cyclical apoptotic activity in anterior pituitary cells during the oestrous cycle. Considering that tissue homeostasis results from a balance between cell proliferation and death and that mechanisms involved in apoptosis are tightly regulated, defects in cell death processes could have a considerable physiopathological impact.

Tissue Cells Feel and Respond to the Stiffness of Their Substrate

NASA Astrophysics Data System (ADS)

Discher, Dennis E.; Janmey, Paul; Wang, Yu-li

2005-11-01

Normal tissue cells are generally not viable when suspended in a fluid and are therefore said to be anchorage dependent. Such cells must adhere to a solid, but a solid can be as rigid as glass or softer than a baby's skin. The behavior of some cells on soft materials is characteristic of important phenotypes; for example, cell growth on soft agar gels is used to identify cancer cells. However, an understanding of how tissue cells-including fibroblasts, myocytes, neurons, and other cell types-sense matrix stiffness is just emerging with quantitative studies of cells adhering to gels (or to other cells) with which elasticity can be tuned to approximate that of tissues. Key roles in molecular pathways are played by adhesion complexes and the actin-myosin cytoskeleton, whose contractile forces are transmitted through transcellular structures. The feedback of local matrix stiffness on cell state likely has important implications for development, differentiation, disease, and regeneration.

The Caenorhabditis elegans Ephrin EFN-4 Functions Non-cell Autonomously with Heparan Sulfate Proteoglycans to Promote Axon Outgrowth and Branching

PubMed Central

Schwieterman, Alicia A.; Steves, Alyse N.; Yee, Vivian; Donelson, Cory J.; Bentley, Melissa R.; Santorella, Elise M.; Mehlenbacher, Taylor V.; Pital, Aaron; Howard, Austin M.; Wilson, Melissa R.; Ereddia, Danielle E.; Effrein, Kelsie S.; McMurry, Jonathan L.; Ackley, Brian D.; Chisholm, Andrew D.; Hudson, Martin L.

2016-01-01

The Eph receptors and their cognate ephrin ligands play key roles in many aspects of nervous system development. These interactions typically occur within an individual tissue type, serving either to guide axons to their terminal targets or to define boundaries between the rhombomeres of the hindbrain. We have identified a novel role for the Caenorhabditis elegans ephrin EFN-4 in promoting primary neurite outgrowth in AIY interneurons and D-class motor neurons. Rescue experiments reveal that EFN-4 functions non-cell autonomously in the epidermis to promote primary neurite outgrowth. We also find that EFN-4 plays a role in promoting ectopic axon branching in a C. elegans model of X-linked Kallmann syndrome. In this context, EFN-4 functions non-cell autonomously in the body-wall muscle and in parallel with HS modification genes and HSPG core proteins. This is the first report of an epidermal ephrin providing a developmental cue to the nervous system. PMID:26645816

p110α and p110β isoforms of PI3K signaling: are they two sides of the same coin?

PubMed

Singh, Paramjeet; Dar, Mohd Saleem; Dar, Mohd Jamal

2016-09-01

Class-1 phosphatidylinositol-3-kinases (PI3Ks) are activated by a variety of extracellular stimuli and have been implicated in a wide range of cellular processes. p110α and p110β are the two most studied isoforms of the class-1A PI3K signaling pathway. Although these two isoforms are ubiquitously expressed and play multiple redundant roles, they also have distinct functions within the cell. More recently, p110α and p110β isoforms have been shown to translocate into the nucleus and play a role in DNA replication and repair, and in cell cycle progression. In the following Review article, we discuss the overlapping and unique roles of p110α and p110β isoforms with a particular focus on their structure, expression analysis, subcellular localization, and signaling contributions in various cell types and model organisms. © 2016 Federation of European Biochemical Societies.

Cell- and stage-specific localization of galectin-3, a β-galactoside-binding lectin, in a mouse model of experimental autoimmune encephalomyelitis.

PubMed

Itabashi, Tetsuya; Arima, Yasunobu; Kamimura, Daisuke; Higuchi, Kotaro; Bando, Yoshio; Takahashi-Iwanaga, Hiromi; Murakami, Masaaki; Watanabe, Masahiko; Iwanaga, Toshihiko; Nio-Kobayashi, Junko

2018-06-16

Multiple sclerosis (MS) is an autoimmune disease in which pathogenic T cells play an important role, and an experimental autoimmune encephalomyelitis (EAE) is used as an animal model of MS. Galectins are β-galactoside-binding lectins and involved in various physiological and pathological events. Among fifteen members of galectins, galectin-1, -8, and -9 play immunosuppressive roles in MS and EAE; however, the role of galectin-3 (gal-3) is complex and controversial. We examined expression of gal-3 in the spinal cord and nerve roots of EAE mice. No immunohistochemical signals were detected in naïve mice, whereas gal-3 appeared at lower lumbar levels of the spinal cord and nerve roots in EAE mice. In the spinal cord, gal-3-positive cells were activated microglia and/or infiltrating macrophages, which were round in shape and intensified for the lysosomal enzyme, cathepsin D, indicating elevated phagocytic activity. Gal-3-positive cells in the spinal cord were most abundant during the peak symptomatic period. In the recovery period, they disappeared from the spinal parenchyma but remained at moderate levels in the pia mater. Interestingly, gal-3-positive cells selectively appeared in ventral, but not dorsal, nerve roots running through the spinal canal, with expression peaking during the recovery period. In ventral nerve roots, the major cell type expressing gal-3 was a specific population of Schwann cells that surround unmyelinated axons and express the biosynthetic enzyme for l-serine, a potent neurotrophic amino acid. Gal-3 was also induced in Iba1/F4/80-positive macrophages, which engulf damaged myelin and axon debris. Thus, gal-3 is induced in distinct cell types that are engaged in removal of damaged axons and cell debris and axon regeneration and remyelination, suggesting a potential neuroprotective role of gal-3 in EAE mice. Copyright © 2018. Published by Elsevier Ltd.

Interaction of HTLV-1 Tax protein with calreticulin: implications for Tax nuclear export and secretion.

PubMed

Alefantis, Timothy; Flaig, Katherine E; Wigdahl, Brian; Jain, Pooja

2007-05-01

Human T cell leukemia virus type 1 (HTLV-1) is the etiologic agent of adult T cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The HTLV-1 transcriptional transactivator protein Tax plays an integral role in virus replication and disease progression. Traditionally, Tax is described as a nuclear protein where it performs its primary role as a transcriptional transactivator. However, recent studies have clearly shown that Tax can also be localized to the cytoplasm where it has been shown to interact with a number of host transcription factors most notably NF-kappaB, constitutive expression of which is directly related to the T cell transforming properties of Tax in ATL patients. The presence of a functional nuclear export signal (NES) within Tax and the secretion of full-length Tax have also been demonstrated previously. Additionally, release of Tax from HTLV-1-infected cells and the presence of cell-free Tax was demonstrated in the CSF of HAM/TSP patients suggesting that the progression to HAM/TSP might be mediated by the ability of Tax to function as an extracellular cytokine. Therefore, in both ATL and HAM/TSP Tax nuclear export and nucleocytoplasmic shuttling may play a critical role, the mechanism of which remains unknown. In this study, we have demonstrated that the calcium binding protein calreticulin interacts with Tax by co-immunoprecipitation. This interaction was found to localize to a region at or near the nuclear membrane. In addition, differential expression of calreticulin was demonstrated in various cell types that correlated with their ability to retain cytoplasmic Tax, particularly in astrocytes. Finally, a comparison of a number of HTLV-1-infected T cell lines to non-infected T cells revealed higher expression of calreticulin in infected cells implicating a direct role for this protein in HTLV-1 infection.

Necroptosis Takes Place in Human Immunodeficiency Virus Type-1 (HIV-1)-Infected CD4+ T Lymphocytes

PubMed Central

Pan, Ting; Wu, Shuangxin; He, Xin; Luo, Haihua; Zhang, Yijun; Fan, Miaomiao; Geng, Guannan; Ruiz, Vivian Clarke; Zhang, Jim; Mills, Lisa; Bai, Chuan; Zhang, Hui

2014-01-01

Human immunodeficiency virus type 1 (HIV-1) infection is characterized by progressive depletion of CD4+ T lymphocytes and dysfunction of the immune system. The numbers of CD4+ T lymphocytes in the human body are maintained constantly by homeostatic mechanisms that failed during HIV-1 infection, resulting in progressive loss of CD4+ T cells mainly via apoptosis. Recently, a non-apoptotic form of necrotic programmed cell death, named necroptosis, has been investigated in many biological and pathological processes. We then determine whether HIV-1-infected cells also undergo necroptosis. In this report, we demonstrate that HIV-1 not only induces apoptosis, but also mediates necroptosis in the infected primary CD4+ T lymphocytes and CD4+ T-cell lines. Necroptosis-dependent cytopathic effects are significantly increased in HIV-1-infected Jurkat cells that is lack of Fas-associated protein-containing death domain (FADD), indicating that necroptosis occurs as an alternative cell death mechanism in the absence of apoptosis. Unlike apoptosis, necroptosis mainly occurs in HIV-infected cells and spares bystander damage. Treatment with necrostatin-1(Nec-1), a RIP1 inhibitor that specifically blocks the necroptosis pathway, potently restrains HIV-1-induced cytopathic effect and interestingly, inhibits the formation of HIV-induced syncytia in CD4+ T-cell lines. This suggests that syncytia formation is mediated, at least partially, by necroptosis-related processes. Furthermore, we also found that the HIV-1 infection-augmented tumor necrosis factor-alpha (TNF-α) plays a key role in inducing necroptosis and HIV-1 Envelope and Tat proteins function as its co-factors. Taken together,necroptosis can function as an alternative cell death pathway in lieu of apoptosis during HIV-1 infection, thereby also contributing to HIV-1-induced cytopathic effects. Our results reveal that in addition to apoptosis, necroptosis also plays an important role in HIV-1-induced pathogenesis. PMID:24714696

p38 MAPK pathway is essential for self-renewal of mouse male germline stem cells (mGSCs).

PubMed

Niu, Zhiwei; Mu, Hailong; Zhu, Haijing; Wu, Jiang; Hua, Jinlian

2017-02-01

Male germline stem cells (mGSCs), also called spermatogonial stem cells (SSCs), constantly generate spermatozoa in male animals. A number of preliminary studies on mechanisms of mGSC self-renewal have previously been conducted, revealing that several factors are involved in this regulated process. The p38 MAPK pathway is widely conserved in multiple cell types in vivo, and plays an important role in cell proliferation, differentiation, inflammation and apoptosis. However, its role in self-renewal of mGSCs has not hitherto been determined. Here, the mouse mGSCs were cultured and their identity was verified by semi-RT-PCR, alkaline phosphatase (AP) staining and immunofluorescence staining. Then, the p38 MAPK pathway was blocked by p38 MAPK-specific inhibitor SB202190. mGSC self-renewal ability was then analysed by observation of morphology, cell number, cell growth analysis, TUNEL incorporation assay and cell cycle analysis. Results showed that mouse mGSC self-renewal ability was significantly inhibited by SB202190. This study showed for the first time that the p38 MAPK pathway plays a key role in maintaining self-renewal capacity of mouse mGSCs, which offers a new self-renewal pathway for these cells and contributes to overall knowledge of the mechanisms of mGSC self-renewal. © 2016 John Wiley & Sons Ltd.

Innate immune responses in central nervous system inflammation.

PubMed

Finsen, Bente; Owens, Trevor

2011-12-01

In autoimmune diseases of the central nervous system (CNS), innate glial cell responses play a key role in determining the outcome of leukocyte infiltration. Access of leukocytes is controlled via complex interactions with glial components of the blood-brain barrier that include angiotensin II receptors on astrocytes and immunoregulatory mediators such as Type I interferons which regulate cellular traffic. Myeloid cells at the blood-brain barrier present antigen to T cells and influence cytokine effector function. Myelin-specific T cells interact with microglia and promote differentiation of oligodendrocyte precursor cells in response to axonal injury. These innate responses offer potential targets for immunomodulatory therapy. Copyright © 2011 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Microgravity

NASA Image and Video Library

2004-04-15

Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. The objective of the research was to define a way to differentiate between effects due to microgravity and those due to possible stress from non-optimal spaceflight conditions. These Jurkat cells, a human acute T-cell leukemia was obtained to evaluate three types of potential experimental stressors: a) Temperature elevation; b) Serum starvation; and c) Centrifugal force. The data from previous spaceflight experiments showed that actin filaments and cell shape are significantly different for the control. These normal cells serve as the baseline for future spaceflight experiments.

Coordinated encoding between cell types in the retina: insights from the theory of phase transitions

NASA Astrophysics Data System (ADS)

Sharpee, Tatyana

2015-03-01

In this talk I will describe how the emergence of some types of neurons in the brain can be quantitatively described by the theory of transitions between different phases of matter. The two key parameters that control the separation of neurons into subclasses are the mean and standard deviation of noise levels among neurons in the population. The mean noise level plays the role of temperature in the classic theory of phase transitions, whereas the standard deviation is equivalent to pressure, in the case of liquid-gas transitions, or to magnetic field for magnetic transitions. Our results account for properties of two recently discovered types of salamander OFF retinal ganglion cells, as well as the absence of multiple types of ON cells. We further show that, across visual stimulus contrasts, retinal circuits continued to operate near the critical point whose quantitative characteristics matched those expected near a liquid-gas critical point and described by the nearest-neighbor Ising model in three dimensions. Because the retina needs to operate under changing stimulus conditions, the observed parameters of cell types corresponded to metastable states in the region between the spinodal line and the line describing maximally informative solutions. Such properties of neural circuits can maximize information transmission in a given environment while retaining the ability to quickly adapt to a new environment. NSF CAREER award 1254123 and NIH R01EY019493

A B-type histone acetyltransferase Hat1 regulates secondary metabolism, conidiation, and cell wall integrity in the taxol-producing fungus Pestalotiopsis microspora.

PubMed

Zhang, Qian; Chen, Longfei; Yu, Xi; Liu, Heng; Akhberdi, Oren; Pan, Jiao; Zhu, Xudong

2016-12-01

In filamentous fungi, many gene clusters for the biosynthesis of secondary metabolites often stay silent under laboratory culture conditions because of the absence of communication with its natural environment. Epigenetic processes have been demonstrated to be critical in the expression of the genes or gene clusters. Here, we report the identification of a B-type histone acetyltransferase, Hat1, and demonstrate its significant roles in secondary metabolism, conidiation, and the cell wall integrity in the fungus Pestalotiopsis microspora. An hat1 deletion strain shows a dramatic decrease of SMs in this fungus, suggesting hat1 functions as a global regulator on secondary metabolism. Moreover, the mutant strain hat1Δ delays to produce conidia with significantly decreased number of conidia, while shows little effect on vegetative growth, suggesting that it plays a critical role in conidiation. The hypersensitivity of hat1Δ to Congo red demonstrates that disruption of hat1 impairs the integrity of cell wall. Overexpression of the wild-type hat1 allele enhances conidiation by boosting the number of conidia. This is the first report on the role of a B-type histone acetyltransferase in fungal secondary metabolism and cell wall integrity. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.