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Sample records for connexin26 null mice

  1. Virally-expressed connexin26 restores gap junction function in the cochlea of conditional Gjb2 knockout mice

    PubMed Central

    Yu, Qing; Wang, Yunfeng; Chang, Qing; Wang, Jianjun; Gong, Shushen; Li, Huawei; Lin, Xi

    2013-01-01

    Mutations in GJB2, which codes for the gap junction protein connexin26, are the most common causes of human nonsyndromic hereditary deafness. We inoculated modified adeno-associated viral vectors into the scala media of early postnatal conditional Gjb2 knockout mice to drive exogenous connexin26 expression. We found extensive virally-expressed connexin26 in cells lining the scala media, and intercellular gap junction network was re-established in the organ of Corti of mutant mouse cochlea. Widespread ectopic connexin26 expression neither formed ectopic gap junctions nor affected normal hearing thresholds in wild type mice, suggesting that autonomous cellular mechanisms regulate proper membrane trafficking of exogenously-expressed connexin26 and govern the functional manifestation of them. Functional recovery of gap-junction-mediated coupling among the supporting cells was observed. We found that both cell death in the organ of Corti and degeneration of spiral ganglion neurons in the cochlea of mutant mice were substantially reduced, although auditory brainstem responses did not show significant hearing improvement. This is the first report demonstrating that virally-mediated gene therapy restored extensive gap junction intercellular network among cochlear non-sensory cells in vivo. Such a treatment performed at early postnatal stages resulted in a partial rescue of disease phenotypes in the cochlea of the mutant mice. PMID:24225640

  2. Reduced Connexin26 in the Mature Cochlea Increases Susceptibility to Noise-Induced Hearing Lossin Mice.

    PubMed

    Zhou, Xing-Xing; Chen, Sen; Xie, Le; Ji, Yu-Zi; Wu, Xia; Wang, Wen-Wen; Yang, Qi; Yu, Jin-Tao; Sun, Yu; Lin, Xi; Kong, Wei-Jia

    2016-01-01

    Connexin26 (Cx26, encoded by GJB2) mutations are the most common cause of non-syndromic deafness. GJB2 is thought to be involved in noise-induced hearing loss (NIHL). However, the role of Cx26 in NIHL is still obscure. To explore the association between Cx26 and NIHL, we established a Cx26 knockdown (KD) mouse model by conditional knockdown of Cx26 at postnatal day 18 (P18), and then we observed the auditory threshold and morphologic changes in these mice with or without noise exposure. The Cx26 KD mice did not exhibit substantial hearing loss and hair cell degeneration, while the Cx26 KD mice with acoustic trauma experienced higher hearing loss than simple noise exposure siblings and nearly had no recovery. Additionally, extensive outer hair cell loss and more severe destruction of the basal organ of Corti were observed in Cx26 KD mice after noise exposure. These data indicate that reduced Cx26 expression in the mature mouse cochlea may increase susceptibility to noise-induced hearing loss and facilitate the cell degeneration in the organ of Corti. PMID:26927086

  3. Peripheral lymphangiogenesis in mice depends on ectodermal connexin-26 (Gjb2).

    PubMed

    Dicke, Nikolai; Pielensticker, Nicole; Degen, Joachim; Hecker, Julia; Tress, Oliver; Bald, Tobias; Gellhaus, Alexandra; Winterhager, Elke; Willecke, Klaus

    2011-08-15

    In order to study the specific function of connexin-26 (Cx26, also known as gap junction beta-2 protein; Gjb2), we generated knockin mice that expressed either a floxed lacZ reporter or, after Cre-mediated deletion, connexin-32 (Cx32)-coding DNA, both driven by the endogenous Cx26 promoter. Heterozygous Cx26knock-inCx32 (Cx26KICx32) embryos developed normally until embryonic day 14.5 but died before birth with severe lymphedemas. Although the jugular lymph sacs were normally developed, these embryos had a strongly reduced dermal lymphatic capillary network. By analyses of β-galactosidase reporter protein expression and lymphatic or blood endothelial-specific marker proteins, we demonstrated that Cx26 expression is temporally closely linked to lymphangiogenesis. No obvious phenotypic abnormalities were observed in Cx26KICx32 mice when Cre-mediated recombination was directed to mesenchyme or blood endothelium using the Prx1-Cre or Tie2-Cre mouse strains, respectively. By contrast, keratin-5-Cre-mediated replacement of Cx26 with Cx32 or deletion of both Cx26 alleles revealed severe lymphedemas similar to the general Cx26KICx32 phenotype. Thus, conditional ablation of Cx26 (loss of function) in ectoderm leads to partial disruption of lymphatic capillaries and embryonic death. We conclude that appropriate development of dermal lymphatic vessels in mice is dependent on the expression of Cx26 in the ectoderm. PMID:21807945

  4. Connexin26 expression in brain parenchymal cells demonstrated by targeted connexin ablation in transgenic mice.

    PubMed

    Nagy, J I; Lynn, B D; Tress, O; Willecke, K; Rash, J E

    2011-07-01

    Astrocytes are known to express the gap junction forming proteins connexin30 (Cx30) and connexin43 (Cx43), but it has remained controversial whether these cells also express connexin26 (Cx26). To investigate this issue further, we examined immunofluorescence labelling of glial connexins in wild-type vs. transgenic mice with targeted deletion of Cx26 in neuronal and glial cells (Cx26fl/fl:Nestin-Cre mice). The Cx26 antibodies utilized specifically recognized Cx26 and lacked cross reaction with highly homologous Cx30, as demonstrated by immunoblotting and immunofluorescence in Cx26-transfected and Cx30-transfected C6 glioma cells. Punctate immunolabelling of Cx26 with these antibodies was observed in leptomeninges and subcortical brain regions. This labelling was absent in subcortical areas of Cx26fl/fl:Nestin-Cre mice, but persisted in leptomeningeal tissues of these mice, thereby distinguishing localization of Cx26 between parenchymal and non-parenchymal tissue. In subcortical brain parenchyma, Cx26-positive puncta were often co-localized with astrocytic Cx43, and some were localized along astrocyte cell bodies and processes immunolabelled for glial fibrillary acidic protein. Cx26-positive puncta were also co-localized with punctate labelling of Cx47 around oligodendrocyte somata. Comparisons of Cx26 labelling in rodent species revealed a lower density of Cx26-positive puncta and a more restricted distribution in subcortical regions of mouse compared with rat brain, perhaps partly explaining reported difficulties in detection of Cx26 in mouse brain parenchyma using antibodies or Cx26 gene reporters. These results support our earlier observations of Cx26 expression in astrocytes and its ultrastructural localization in individual gap junction plaques formed between astrocytes as well as in heterotypic gap junctions between astrocytes and oligodendrocytes. PMID:21714813

  5. Ablation of connexin30 in transgenic mice alters expression patterns of connexin26 and connexin32 in glial cells and leptomeninges.

    PubMed

    Lynn, B D; Tress, O; May, D; Willecke, K; Nagy, J I

    2011-12-01

    Expression of connexin26 (Cx26), Cx30 and Cx43 in astrocytes and expression of Cx29, Cx32 and Cx47 in oligodendrocytes of adult rodent brain has been well documented, as has the interdependence of connexin expression patterns of macroglial cells in Cx32- and Cx47-knockout mice. To investigate this interdependence further, we examined immunofluorescence labelling of glial connexins in transgenic Cx30 null mice. Ablation of astrocytic Cx30, confirmed by the absence of immunolabelling for this connexin in all brain regions, resulted in the loss of its coupling partner Cx32 on the oligodendrocyte side of astrocyte-oligodendrocyte (A/O) gap junctions, but had no effect on the localization of astrocytic Cx43 and oligodendrocytic Cx47 at these junctions or on the distribution of Cx32 along myelinated fibres. Surprisingly, gene deletion of Cx30 led to the near total elimination of immunofluorescence labelling for Cx26 in all leptomeningeal tissues covering brain surfaces as well as in astrocytes of brain parenchyma. Moreover northern blot analysis revealed downregulation of Cx26 mRNA in Cx30-knockout brains. Our results support earlier observations on the interdependency of Cx30/Cx32 targeting to A/O gap junctions and further suggest that Cx26 mRNA expression is affected by Cx30 gene expression. In addition, Cx30 protein may be required for co-stabilization of gap junctions or for co-trafficking in cells. PMID:22098503

  6. Reduced Connexin26 in the Mature Cochlea Increases Susceptibility to Noise-Induced Hearing Loss in Mice

    PubMed Central

    Zhou, Xing-Xing; Chen, Sen; Xie, Le; Ji, Yu-Zi; Wu, Xia; Wang, Wen-Wen; Yang, Qi; Yu, Jin-Tao; Sun, Yu; Lin, Xi; Kong, Wei-Jia

    2016-01-01

    Connexin26 (Cx26, encoded by GJB2) mutations are the most common cause of non-syndromic deafness. GJB2 is thought to be involved in noise-induced hearing loss (NIHL). However, the role of Cx26 in NIHL is still obscure. To explore the association between Cx26 and NIHL, we established a Cx26 knockdown (KD) mouse model by conditional knockdown of Cx26 at postnatal day 18 (P18), and then we observed the auditory threshold and morphologic changes in these mice with or without noise exposure. The Cx26 KD mice did not exhibit substantial hearing loss and hair cell degeneration, while the Cx26 KD mice with acoustic trauma experienced higher hearing loss than simple noise exposure siblings and nearly had no recovery. Additionally, extensive outer hair cell loss and more severe destruction of the basal organ of Corti were observed in Cx26 KD mice after noise exposure. These data indicate that reduced Cx26 expression in the mature mouse cochlea may increase susceptibility to noise-induced hearing loss and facilitate the cell degeneration in the organ of Corti. PMID:26927086

  7. Connexin26 regulates assembly and maintenance of cochlear gap junction macromolecular complex for normal hearing

    NASA Astrophysics Data System (ADS)

    Kamiya, Kazusaku; Fukunaga, Ichiro; Hatakeyama, Kaori; Ikeda, Katsuhisa

    2015-12-01

    Hereditary deafness affects about 1 in 2000 children and GJB2 gene mutation is most frequent cause for this disease in the world. GJB2 encodes connexin26 (Cx26), a component in cochlear gap junction. Recently, we found macromolecular change of gap junction plaques with two different types of Cx26 mutation as major classification of clinical case, one is a model of dominant negative type, Cx26R75W+ and the other is conditional gene deficient mouse, Cx26f/fP0Cre as a model for insufficiency of gap junction protein [6]. Gap junction composed mainly of Cx26 and Cx30 in wild type mice formed large planar gap junction plaques (GJP). In contrast, Cx26R75W+ and Cx26f/fP0Cre showed fragmented small round GJPs around the cell border. In Cx26f/fP0Cre, some of the cells with Cx26 expression due to their cellular mosaicism showed normal large GJP with Cx26 and Cx30 only at the cell junction site between two Cx26 positive cells. These indicate that bilateral Cx26 expressions from both adjacent cells are essential for the formation of the cochlear linear GJP, and it is not compensated by other cochlear Connexins such as Connexin30. In the present study, we demonstrated a new molecular pathology in most common hereditary deafness with different types of Connexin26 mutations, and this machinery can be a new target for drag design of hereditary deafness.

  8. Context-specific protection of TGFα null mice from osteoarthritis

    PubMed Central

    Usmani, Shirine E.; Ulici, Veronica; Pest, Michael A.; Hill, Tracy L.; Welch, Ian D.; Beier, Frank

    2016-01-01

    Transforming growth factor alpha (TGFα) is a growth factor involved in osteoarthritis (OA). TGFα induces an OA-like phenotype in articular chondrocytes, by inhibiting matrix synthesis and promoting catabolic factor expression. To better understand TGFα’s potential as a therapeutic target, we employed two in vivo OA models: (1) post-traumatic and (2) aging related OA. Ten-week old and six-month old male Tgfa null mice and their heterozygous (control) littermates underwent destabilization of the medial meniscus (DMM) surgery. Disease progression was assessed histologically using the Osteoarthritis Research Society International (OARSI) scoring system. As well, spontaneous disease progression was analyzed in eighteen-month-old Tgfa null and heterozygous mice. Ten-week old Tgfa null mice were protected from OA progression at both seven and fourteen weeks post-surgery. No protection was seen however in six-month old null mice after DMM surgery, and no differences were observed between genotypes in the aging model. Thus, young Tgfa null mice are protected from OA progression in the DMM model, while older mice are not. In addition, Tgfa null mice are equally susceptible to spontaneous OA development during aging. Thus, TGFα might be a valuable therapeutic target in some post-traumatic forms of OA, however its role in idiopathic disease is less clear. PMID:27457421

  9. Context-specific protection of TGFα null mice from osteoarthritis.

    PubMed

    Usmani, Shirine E; Ulici, Veronica; Pest, Michael A; Hill, Tracy L; Welch, Ian D; Beier, Frank

    2016-01-01

    Transforming growth factor alpha (TGFα) is a growth factor involved in osteoarthritis (OA). TGFα induces an OA-like phenotype in articular chondrocytes, by inhibiting matrix synthesis and promoting catabolic factor expression. To better understand TGFα's potential as a therapeutic target, we employed two in vivo OA models: (1) post-traumatic and (2) aging related OA. Ten-week old and six-month old male Tgfa null mice and their heterozygous (control) littermates underwent destabilization of the medial meniscus (DMM) surgery. Disease progression was assessed histologically using the Osteoarthritis Research Society International (OARSI) scoring system. As well, spontaneous disease progression was analyzed in eighteen-month-old Tgfa null and heterozygous mice. Ten-week old Tgfa null mice were protected from OA progression at both seven and fourteen weeks post-surgery. No protection was seen however in six-month old null mice after DMM surgery, and no differences were observed between genotypes in the aging model. Thus, young Tgfa null mice are protected from OA progression in the DMM model, while older mice are not. In addition, Tgfa null mice are equally susceptible to spontaneous OA development during aging. Thus, TGFα might be a valuable therapeutic target in some post-traumatic forms of OA, however its role in idiopathic disease is less clear. PMID:27457421

  10. Functional hemichannels formed by human connexin 26 expressed in bacteria

    PubMed Central

    Fiori, Mariana C.; Krishnan, Srinivasan; Cortes, D. Marien; Retamal, Mauricio A.; Reuss, Luis; Altenberg, Guillermo A.; Cuello, Luis G.

    2015-01-01

    Gap-junction channels (GJCs) communicate the cytoplasm of adjacent cells and are formed by head-to-head association of two hemichannels (HCs), one from each of the neighbouring cells. GJCs mediate electrical and chemical communication between cells, whereas undocked HCs participate in paracrine signalling because of their permeability to molecules such as ATP. Sustained opening of HCs under pathological conditions results in water and solute fluxes that cannot be compensated by membrane transport and therefore lead to cell damage. Mutations of Cx26 (connexin 26) are the most frequent cause of genetic deafness and it is therefore important to understand the structure–function relationship of wild-type and deafness-associated mutants. Currently available connexin HC expression systems severely limit the pace of structural studies and there is no simple high-throughput HC functional assay. The Escherichia coli-based expression system presented in the present study yields milligram amounts of purified Cx26 HCs suitable for functional and structural studies. We also show evidence of functional activity of recombinant Cx26 HCs in intact bacteria using a new growth complementation assay. The E. coli-based expression system has high potential for structural studies and high-throughput functional screening of HCs. PMID:25585383

  11. Screening of Connexin 26 in Nonsyndromic Hearing Loss

    PubMed Central

    Moreira, Danielle; Silva, Daniela da; Lopez, Priscila; Mantovani, Jair Cortez

    2014-01-01

    Introduction The first locus for nonsyndromic autosomal recessive hearing loss is on chromosome 13q11–22. The 35delG mutation is present in 80% of cases in which GJB2 is involved, which makes the study of this mutation very important. The viability and benefits of screening for mutations in the connexin 26 gene are now beginning to change the diagnostic evaluation and identification of the etiology of hearing loss. Objective To investigate the occurrence of the 35delG mutation in patients with nonsyndromic sensorineural hearing loss and their first degree relatives. Methods This transversal study included 72 patients from the local hospital. The patients were divided into three groups: group A, sensorineural hearing loss (n = 58); group B, first-degree relatives of group A with sensorineural hearing loss (n = 09); and group C, first-degree relatives of patients from group A without hearing loss (n = 05). All patients had audiological evaluation and genetic testing of the 35delG mutation. Results The 35delG mutation was found in four heterozygous mutations (three of them found in the same family). The other heterozygous mutation was found in a female patient with bilateral, moderate, prelingual, sensorineural hearing loss. A single homozygous mutation was found in a male patient, with severe sensorineural hearing loss in his right ear and profound hearing loss in the left ear. Conclusions The 35delG mutation was found in 7% of the cases. The test is easy to perform and inexpensive, but it is necessary to investigate other genes related to hearing loss. PMID:25992148

  12. Computational Studies of Molecular Permeation through Connexin26 Channels.

    PubMed

    Luo, Yun; Rossi, Angelo R; Harris, Andrew L

    2016-02-01

    A signal property of connexin channels is the ability to mediate selective diffusive movement of molecules through plasma membrane(s), but the energetics and determinants of molecular movement through these channels have yet to be understood. Different connexin channels have distinct molecular selectivities that cannot be explained simply on the basis of size or charge of the permeants. To gain insight into the forces and interactions that underlie selective molecular permeation, we investigated the energetics of two uncharged derivatized sugars, one permeable and one impermeable, through a validated connexin26 (Cx26) channel structural model, using molecular dynamics and associated analytic tools. The system is a Cx26 channel equilibrated in explicit membrane/solvent, shown by Brownian dynamics to reproduce key conductance characteristics of the native channel. The results are consistent with the known difference in permeability to each molecule. The energetic barriers extend through most of the pore length, rather than being highly localized as in ion-specific channels. There is little evidence for binding within the pore. Force decomposition reveals how, for each tested molecule, interactions with water and the Cx26 protein vary over the length of the pore and reveals a significant contribution from hydrogen bonding and interaction with K(+). The flexibility of the pore width varies along its length, and the tested molecules have differential effects on pore width as they pass through. Potential sites of interaction within the pore are defined for each molecule. The results suggest that for the tested molecules, differences in hydrogen bonding and entropic factors arising from permeant flexibility substantially contribute to the energetics of permeation. This work highlights factors involved in selective molecular permeation that differ from those that define selectivity among atomic ions. PMID:26840724

  13. sirt1-null mice develop an autoimmune-like condition

    SciTech Connect

    Sequeira, Jedon; Boily, Gino; Bazinet, Stephanie; Saliba, Sarah; He Xiaohong; Jardine, Karen; Kennedy, Christopher; Staines, William; Rousseaux, Colin; Mueller, Rudi; McBurney, Michael W.

    2008-10-01

    The sirt1 gene encodes a protein deacetylase with a broad spectrum of reported substrates. Mice carrying null alleles for sirt1 are viable on outbred genetic backgrounds so we have examined them in detail to identify the biological processes that are dependent on SIRT1. Sera from adult sirt1-null mice contain antibodies that react with nuclear antigens and immune complexes become deposited in the livers and kidneys of these animals. Some of the sirt1-null animals develop a disease resembling diabetes insipidus when they approach 2 years of age although the relationship to the autoimmunity remains unclear. We interpret these observations as consistent with a role for SIRT1 in sustaining normal immune function and in this way delaying the onset of autoimmune disease.

  14. Modified sympathetic nerve regulation in AKAP5-null mice.

    PubMed

    Han, Chong; Tomita, Hirofumi; Ohba, Takayoshi; Nishizaki, Kimitaka; Ogata, Yoshiki; Matsuzaki, Yasushi; Sawamura, Daisuke; Yanagisawa, Teruyuki; Osanai, Tomohiro; Imaizumi, Tadaatsu; Matsubara, Atsushi; Adachi, Takeshi; Ono, Kyoichi; Okumura, Ken; Murakami, Manabu

    2016-01-22

    Genetic analyses have revealed an important association between A-kinase anchoring proteins (AKAPs) and the intracellular calcium modulating system. AKAP5, also known as AKAP79/150, is an anchoring protein between PKA and voltage-dependent calcium channels, ryanodine receptor-2, phospholamban and other molecules. The aim of the present study was to elucidate the physiological importance of AKAP5 in the creation of cardiac rhythm using AKAP5-null mice. ECG analysis showed a normal sinus rhythm and a decreased responsiveness to isoproterenol in AKAP5-null mice compared with wild-type mice. Analysis of heart rate variability revealed that the R-R interval was unstable in AKAP5-null mutants and that the low-frequency components had decreased, indicating that the tonus of the sympathetic nervous system was affected. Furthermore, the atrium of the AKAP5-null mice showed a decreased positive inotropic response to isoproterenol, indicating the involvement of AKAP5 in a PKA-dependent pathway. Thus, our present study revealed that AKAP5 plays a significant role in the regulation of sympathetic nerve activities. PMID:26713362

  15. Defective intestinal amino acid absorption in Ace2 null mice.

    PubMed

    Singer, Dustin; Camargo, Simone M R; Ramadan, Tamara; Schäfer, Matthias; Mariotta, Luca; Herzog, Brigitte; Huggel, Katja; Wolfer, David; Werner, Sabine; Penninger, Josef M; Verrey, François

    2012-09-15

    Mutations in the main intestinal and kidney luminal neutral amino acid transporter B(0)AT1 (Slc6a19) lead to Hartnup disorder, a condition that is characterized by neutral aminoaciduria and in some cases pellagra-like symptoms. These latter symptoms caused by low-niacin are thought to result from defective intestinal absorption of its precursor L-tryptophan. Since Ace2 is necessary for intestinal B(0)AT1 expression, we tested the impact of intestinal B(0)AT1 absence in ace2 null mice. Their weight gain following weaning was decreased, and Na(+)-dependent uptake of B(0)AT1 substrates measured in everted intestinal rings was defective. Additionally, high-affinity Na(+)-dependent transport of L-proline, presumably via SIT1 (Slc6a20), was absent, whereas glucose uptake via SGLT1 (Slc5a1) was not affected. Measurements of small intestine luminal amino acid content following gavage showed that more L-tryptophan than other B(0)AT1 substrates reach the ileum in wild-type mice, which is in line with its known lower apparent affinity. In ace2 null mice, the absorption defect was confirmed by a severalfold increase of L-tryptophan and of other neutral amino acids reaching the ileum lumen. Furthermore, plasma and muscle levels of glycine and L-tryptophan were significantly decreased in ace2 null mice, with other neutral amino acids displaying a similar trend. A low-protein/low-niacin diet challenge led to differential changes in plasma amino acid levels in both wild-type and ace2 null mice, but only in ace2 null mice to a stop in weight gain. Despite the combination of low-niacin with a low-protein diet, plasma niacin concentrations remained normal in ace2 null mice and no pellagra symptoms, such as photosensitive skin rash or ataxia, were observed. In summary, mice lacking Ace2-dependent intestinal amino acid transport display no total niacin deficiency nor clear pellagra symptoms, even under a low-protein and low-niacin diet, despite gross amino acid homeostasis alterations

  16. Adult sulfatide null mice maintain an increased number of oligodendrocytes

    PubMed Central

    Shroff, S; Pomicter, AD; Fox, MA; Henderson, SC; Dupree, JL

    2015-01-01

    The galactolipids galactocerebroside and sulfatide have been implicated in oligodendrocyte development and myelin formation. Much of the evidence for these galactolipid functions has been derived from antibody and chemical perturbation of cultured oligodendrocytes. Recently, we have observed abundant, unstable myelin and an increased number of oligodendrocytes in mice incapable of synthesizing the myelin galactolipids galactocerebroside and sulfatide. We have also reported that mice lacking sulfatide but that synthesize normal levels of galactocerebroside generate myelin with unstable paranodes while Hirahara et al. (2004) have shown an enhanced population of oligodendrocytes in the forebrain, medulla and cerebellum in immature sulfatide null mice. Here, we demonstrate that an increase in the number of oligodendrocytes in sulfatide null mice is not transient but is maintained through, at least, 7 months of age. Moreover, we demonstrate that the enhanced oligodendrocyte population results from, at least in part, increased cell survival. Finally, sulfatide null oligodendrocytes exhibit decreased morphological complexity, a feature which may relate to increased oligodendrocyte survival. PMID:19224580

  17. Generation of mice with a conditional Lbh null allele.

    PubMed

    Lindley, Linsey E; Briegel, Karoline J

    2013-07-01

    Limb bud and heart (LBH) is a developmentally expressed, tissue-specific transcription cofactor in vertebrates that acts in the WNT signaling pathway, a genetic program critical for embryogenesis and adult tissue homeostasis. Aberrant gain-of-function of LBH is implicated in both human congenital disease and cancer. The normal physiological function of LBH has remained elusive owing to a lack of genetic loss-of-function models. Here, we have generated mice with a conditional null allele of Lbh by flanking exon 2 with loxP sites (Lbh(flox)). Homozygous Lbh(flox) and Lbh(loxP) mice, in which the Neo cassette was removed through FLPe-mediated recombination, were viable and fertile, indicating that these conditional Lbh alleles are fully functional. Lbh(loxP) mice were then crossed with a Rosa26-Cre line, resulting in ubiquitous deletion of exon 2 and abolishment of LBH protein expression. Mice homozygous for the Lbh null allele (Lbh(Δ)(2)) displayed normal embryonic development and postnatal growth with morphologies indistinguishable from wild-type littermates. However, mammary gland development, which occurs primarily after birth, was perturbed. Thus, the conditional Lbh allele will be a valuable tool to uncover the currently unknown tissue-specific roles of LBH in postnatal development and disease. PMID:23495064

  18. Cadmium modulates adipocyte functions in metallothionein-null mice

    SciTech Connect

    Kawakami, Takashige; Nishiyama, Kaori; Kadota, Yoshito; Sato, Masao; Inoue, Masahisa; Suzuki, Shinya

    2013-11-01

    Our previous study has demonstrated that exposure to cadmium (Cd), a toxic heavy metal, causes a reduction of adipocyte size and the modulation of adipokine expression. To further investigate the significance of the Cd action, we studied the effect of Cd on the white adipose tissue (WAT) of metallothionein null (MT{sup −/−}) mice, which cannot form atoxic Cd–MT complexes and are used for evaluating Cd as free ions, and wild type (MT{sup +/+}) mice. Cd administration more significantly reduced the adipocyte size of MT{sup −/−} mice than that of MT{sup +/+} mice. Cd exposure also induced macrophage recruitment to WAT with an increase in the expression level of Ccl2 (MCP-1) in the MT{sup −/−} mice. The in vitro exposure of Cd to adipocytes induce triglyceride release into culture medium, decrease in the expression levels of genes involved in fatty acid synthesis and lipid hydrolysis at 24 h, and at 48 h increase in phosphorylation of the lipid-droplet-associated protein perilipin, which facilitates the degradation of stored lipids in adipocytes. Therefore, the reduction in adipocyte size by Cd may arise from an imbalance between lipid synthesis and lipolysis. In addition, the expression levels of leptin, adiponectin and resistin decreased in adipocytes. Taken together, exposure to Cd may induce unusually small adipocytes and modulate the expression of adipokines differently from the case of physiologically small adipocytes, and may accelerate the risk of developing insulin resistance and type 2 diabetes. - Highlights: • Cd causes a marked reduction in adipocyte size in MT-null mice. • Cd enhances macrophage migration into adipose tissue and disrupt adipokine secretion. • MT gene alleviates Cd-induced adipocyte dysfunctions. • Cd enhances the degradation of stored lipids in adipocytes, mediated by perilipin. • Cd induces unusually small adipocytes and the abnormal expression of adipokines.

  19. Mechanical Forces Exacerbate Periodontal Defects in Bsp-null Mice

    PubMed Central

    Soenjaya, Y.; Foster, B.L.; Nociti, F.H.; Ao, M.; Holdsworth, D.W.; Hunter, G.K.; Somerman, M.J.

    2015-01-01

    Bone sialoprotein (BSP) is an acidic phosphoprotein with collagen-binding, cell attachment, and hydroxyapatite-nucleating properties. BSP expression in mineralized tissues is upregulated at onset of mineralization. Bsp-null (Bsp-/-) mice exhibit reductions in bone mineral density, bone turnover, osteoclast activation, and impaired bone healing. Furthermore, Bsp-/- mice have marked periodontal tissue breakdown, with a lack of acellular cementum leading to periodontal ligament detachment, extensive alveolar bone and tooth root resorption, and incisor malocclusion. We hypothesized that altered mechanical stress from mastication contributes to periodontal destruction observed in Bsp-/- mice. This hypothesis was tested by comparing Bsp-/- and wild-type mice fed with standard hard pellet diet or soft powder diet. Dentoalveolar tissues were analyzed using histology and micro–computed tomography. By 8 wk of age, Bsp-/- mice exhibited molar and incisor malocclusion regardless of diet. Bsp-/- mice with hard pellet diet exhibited high incidence (30%) of severe incisor malocclusion, 10% lower body weight, 3% reduced femur length, and 30% elevated serum alkaline phosphatase activity compared to wild type. Soft powder diet reduced severe incisor malocclusion incidence to 3% in Bsp-/- mice, supporting the hypothesis that occlusal loading contributed to the malocclusion phenotype. Furthermore, Bsp-/- mice in the soft powder diet group featured normal body weight, long bone length, and serum alkaline phosphatase activity, suggesting that tooth dysfunction and malnutrition contribute to growth and skeletal defects reported in Bsp-/- mice. Bsp-/- incisors also erupt at a slower rate, which likely leads to the observed thickened dentin and enhanced mineralization of dentin and enamel toward the apical end. We propose that the decrease in eruption rate is due to a lack of acellular cementum and associated defective periodontal attachment. These data demonstrate the importance of BSP

  20. Mechanical Forces Exacerbate Periodontal Defects in Bsp-null Mice.

    PubMed

    Soenjaya, Y; Foster, B L; Nociti, F H; Ao, M; Holdsworth, D W; Hunter, G K; Somerman, M J; Goldberg, H A

    2015-09-01

    Bone sialoprotein (BSP) is an acidic phosphoprotein with collagen-binding, cell attachment, and hydroxyapatite-nucleating properties. BSP expression in mineralized tissues is upregulated at onset of mineralization. Bsp-null (Bsp(-/-)) mice exhibit reductions in bone mineral density, bone turnover, osteoclast activation, and impaired bone healing. Furthermore, Bsp(-/-) mice have marked periodontal tissue breakdown, with a lack of acellular cementum leading to periodontal ligament detachment, extensive alveolar bone and tooth root resorption, and incisor malocclusion. We hypothesized that altered mechanical stress from mastication contributes to periodontal destruction observed in Bsp(-/-) mice. This hypothesis was tested by comparing Bsp(-/-) and wild-type mice fed with standard hard pellet diet or soft powder diet. Dentoalveolar tissues were analyzed using histology and micro-computed tomography. By 8 wk of age, Bsp(-/-) mice exhibited molar and incisor malocclusion regardless of diet. Bsp(-/-) mice with hard pellet diet exhibited high incidence (30%) of severe incisor malocclusion, 10% lower body weight, 3% reduced femur length, and 30% elevated serum alkaline phosphatase activity compared to wild type. Soft powder diet reduced severe incisor malocclusion incidence to 3% in Bsp(-/-) mice, supporting the hypothesis that occlusal loading contributed to the malocclusion phenotype. Furthermore, Bsp(-/-) mice in the soft powder diet group featured normal body weight, long bone length, and serum alkaline phosphatase activity, suggesting that tooth dysfunction and malnutrition contribute to growth and skeletal defects reported in Bsp(-/-) mice. Bsp(-/-) incisors also erupt at a slower rate, which likely leads to the observed thickened dentin and enhanced mineralization of dentin and enamel toward the apical end. We propose that the decrease in eruption rate is due to a lack of acellular cementum and associated defective periodontal attachment. These data demonstrate the

  1. Osteoclast differentiation and function in aquaglyceroporin AQP9 null mice

    PubMed Central

    Liu, Yangjian; Song, Linhua; Wang, Yiding; Rojek, Aleksandra; Nielsen, Søren; Agre, Peter; Carbrey, Jennifer M.

    2008-01-01

    Background Information Osteoclasts are cells specialized for bone resorption and play important roles in bone growth and calcium homeostasis. Differentiation of osteoclasts involves fusion of bone marrow macrophage mononuclear precursors in response to extracellular signals. A dramatic increase in osteoclast cell volume occurs during osteoclast biogenesis and is believed to be mediated by Aquaporin 9 (AQP9), a membrane protein that can rapidly transport water and other small neutral solutes across cell membranes. Results Here we report an increase in expression of AQP9 during differentiation of a mouse macrophage cell line into osteoclasts. Bone marrow macrophages from wild type and AQP9 null mice differentiate into osteoclasts that have similar morphology, contain comparable numbers of nuclei, and digest synthetic bone to the same extent. Bones from wild type and AQP9 null mice contain similar numbers of osteoclasts and have comparable density and structure as measured by X-ray absorptiometry and micro-computed tomography. Conclusions Our data confirm that AQP9 expression rises during osteoclast biogenesis but indicate that AQP9 is not essential for osteoclast function or differentiation under normal physiological conditions. PMID:18666888

  2. Molecular analysis of connexin26 asparagine14 mutations associated with syndromic skin phenotypes.

    PubMed

    de Zwart-Storm, Eugene A; Rosa, Rafael F M; Martin, Patricia E; Foelster-Holst, Regina; Frank, Jorge; Bau, Ana E K; Zen, Paulo R G; Graziadio, Carla; Paskulin, Giorgio A; Kamps, Miriam A; van Geel, Michel; van Steensel, Maurice A M

    2011-05-01

    Mutations in connexin26, a cutaneous gap junction protein, cause a wide variety of skin disorders including keratitis-ichthyosis-deafness syndrome (KID). We previously delineated a phenotype distinct from KID, hypotrichosis-deafness syndrome, caused by the mutation p.Asn14Lys in connexin26. However, a different mutation at the same location, p.Asn14Tyr, was reported to cause a disorder similar to KID. Distinct substitutions cause different conformational changes to the protein, each with unique consequences for its behaviour. This may explain the phenotypic differences. We found the previously described mutation p.Asn14Tyr in connexin26 in two patients from Brazil and Poland, and observe quite distinct phenotypes distinguishable from classical KID syndrome. We assessed functional consequences of p.Asn14Tyr and p.Asn14Lys, using fluorescently labelled proteins and parachute assay, comparing them with the classical KID mutation p.Asp50Asn. Our analyses show that p.Asn14Tyr, p.Asn14Lys and p.Asp50Asn have different consequences for protein localization and gap junction permeability. However, the differences between the phenotypes we observed cannot be readily explained from effects on protein trafficking or gap junction permeability. PMID:21410767

  3. Impairment in motor learning of somatostatin null mutant mice.

    PubMed

    Zeyda, T; Diehl, N; Paylor, R; Brennan, M B; Hochgeschwender, U

    2001-07-01

    Somatostatin was first identified as a hypothalamic factor which inhibits the release of growth hormone from the anterior pituitary (somatotropin release inhibitory factor, SRIF). Both SRIF and its receptors were subsequently found widely distributed within and outside the nervous system, in the adult as well as in the developing organism. Reflecting this wide distribution, somatostatin has been implicated regulating a diverse array of biological processes. These include body growth, homeostasis, sensory perception, autonomous functions, rate of intestinal absorption, behavior, including cognition and memory, and developmental processes. We produced null mutant mice lacking somatostatin through targeted mutagenesis. The mutant mice are healthy, fertile, and superficially indistinguishable from their heterozygous and wildtype littermates. A 'first round' phenotype screen revealed that mice lacking somatostatin have elevated plasma growth hormone levels, despite normal body size, and have elevated basal plasma corticosterone levels. In order to uncover subtle and unexpected differences, we carried out a systematic behavioral phenotype screen which identified a significant impairment in motor learning revealed when increased demands were made on motor coordination. Motor coordination and motor learning require an intact cerebellum. While somatostatin is virtually absent from the adult cerebellum, the ligand and its receptor(s) are transiently expressed at high levels in the developing cerebellum. This result suggests the functional significance of transient expression of SRIF and its receptors in the development of the cerebellum. PMID:11430867

  4. Reduced arsenic clearance and increased toxicity in aquaglyceroporin-9-null mice

    PubMed Central

    Carbrey, Jennifer M.; Song, Linhua; Zhou, Yao; Yoshinaga, Masafumi; Rojek, Aleksandra; Wang, Yiding; Liu, Yangjian; Lujan, Heidi L.; DiCarlo, Stephen E.; Nielsen, Søren; Rosen, Barry P.; Agre, Peter; Mukhopadhyay, Rita

    2009-01-01

    Expressed in liver, aquaglyceroporin-9 (AQP9) is permeated by glycerol, arsenite, and other small, neutral solutes. To evaluate a possible protective role, AQP9-null mice were evaluated for in vivo arsenic toxicity. After injection with NaAsO2, AQP9-null mice suffer reduced survival rates (LD50, 12 mg/kg) compared with WT mice (LD50, 15 mg/kg). The highest tissue level of arsenic is in heart, with AQP9-null mice accumulating 10–20 times more arsenic than WT mice. Within hours after NaAsO2 injection, AQP9-null mice sustain profound bradycardia, despite normal serum electrolytes. Increased arsenic levels are also present in liver, lung, spleen, and testis of AQP9-null mice. Arsenic levels in the feces and urine of AQP9-null mice are only ≈10% of the WT levels, and reduced clearance of multiple arsenic species by the AQP9-null mice suggests that AQP9 is involved in the export of multiple forms of arsenic. Immunohistochemical staining of liver sections revealed that AQP9 is most abundant in basolateral membrane of hepatocytes adjacent to the sinusoids. AQP9 is not detected in heart or kidney by PCR or immunohistochemistry. We propose that AQP9 provides a route for excretion of arsenic by the liver, thereby providing partial protection of the whole animal from arsenic toxicity. PMID:19805235

  5. Audiologic Phenotype and Progression in GJB2 (Connexin 26) Hearing Loss

    PubMed Central

    Kenna, Margaret A.; Feldman, Henry A.; Neault, Marilyn W.; Frangulov, Anna; Wu, Bai-Lin; Fligor, Brian; Rehm, Heidi L.

    2015-01-01

    Objectives To document the audiologic phenotype of children with biallelic GJB2 (connexin 26) mutations, and to correlate it with the genotype. Design Prospective, observational study. Setting Tertiary care children’s hospital. Patients Infants and children with sensorineural hearing loss (SNHL). Intervention Sequencing of the GJB2 (connexin 26) gene. Main Outcome Measures Degree and progression of SNHL. Results From December 1, 1998, through November 30, 2006, 126 children with biallelic GJB2 mutations were identified. Of the 30 different mutations identified, 13 (43%) were truncating and 17 (57%) were nontruncating; 62 patients had 2 truncating, 30 had 1 truncating and 1 nontruncating, and 17 had 2 nontruncating mutations. Eighty-four patients (67%) initially had measurable hearing in the mild to severe range in at least 1 of 4 frequencies (500, 1000, 2000, or 4000 Hz). Of these 84 patients with residual hearing, 47 (56%) had some degree of progressive hearing loss. Patients with 2 truncating mutations had significantly worse hearing compared with all other groups. Patients who had 1 or 2 copies of either an M34T or a V37I allele had the mildest hearing loss. Conclusions Hearing loss owing to GJB2 mutations ranges from mild to profound and is usually congenital. More than 50% of patients will experience some hearing loss progression, generally gradually but occasionally precipitously. Hearing loss severity may be influenced by genetic factors, such as the degree of preserved protein function in nontruncating mutations, whereas hearing loss progression may be dependent on factors other than the connexin 26 protein. Genetic counseling for patients with GJB2 mutations should include the variable audiologic phenotype and the possibility of progression. PMID:20083784

  6. Delayed development of specific thyroid hormone-regulated events in transthyretin null mice

    PubMed Central

    Monk, Julie A.; Sims, Natalie A.; Dziegielewska, Katarzyna M.; Weiss, Roy E.; Ramsay, Robert G.

    2013-01-01

    Thyroid hormones (THs) are vital for normal postnatal development. Extracellular TH distributor proteins create an intravascular reservoir of THs. Transthyretin (TTR) is a TH distributor protein in the circulatory system and is the only TH distributor protein synthesized in the central nervous system. We investigated the phenotype of TTR null mice during development. Total and free 3′,5′,3,5-tetraiodo-l-thyronine (T4) and free 3′,3,5-triiodo-l-thyronine (T3) in plasma were significantly reduced in 14-day-old (P14) TTR null mice. TTR null mice also displayed a delayed suckling-to-weaning transition, decreased muscle mass, delayed growth, and retarded longitudinal bone growth. In addition, ileums from postnatal day 0 (P0) TTR null mice displayed disordered architecture and contained fewer goblet cells than wild type. Protein concentrations in cerebrospinal fluid from P0 and P14 TTR null mice were higher than in age-matched wild-type mice. In contrast to the current literature based on analyses of adult TTR null mice, our results demonstrate that TTR has an important and nonredundant role in influencing the development of several organs. PMID:23092911

  7. Hepatic Effects of a Methionine-Choline-Deficient Diet in Hepatocyte RXRα-null Mice

    PubMed Central

    Gyamfi, Maxwell Afari; Tanaka, Yuji; He, Lin; Klaassen, Curtis D.; Wan, Yu-Jui Yvonne

    2009-01-01

    Retinoid X receptor-α (RXRα) is an obligate partner for several nuclear hormone receptors that regulate important physiological processes in the liver. In this study the impact of hepatocyte RXRα deficiency on methionine and choline deficient (MCD) diet-induced steatosis, oxidative stress, inflammation, and hepatic transporters gene expression were examined. The mRNA of sterol regulatory element-binding protein (SREBP)-regulated genes, important for lipid synthesis, were not altered in wild type (WT) mice, but were increased 2.0- to 5.4-fold in hepatocyte RXRα-null (H-RXRα-null) mice fed a MCD diet for 14 days. Furthermore, hepatic mRNAs and proteins essential for fatty acid β-oxidation were not altered in WT mice, but were decreased in the MCD diet-fed H-RXRα-null mice, resulting in increased hepatic free fatty acid levels. Cyp2e1 enzyme activity and lipid peroxide levels were induced only in MCD-fed WT mice. In contrast, hepatic mRNA levels of pro-inflammatory factors were increased only in H-RXRα-null mice fed the MCD diet. Hepatic uptake transporters Oatp1a1 and Oatp1b2 mRNA levels were decreased in WT mice fed the MCD diet, whereas the efflux transporter Mrp4 was increased. However, in the H-RXRα-null mice, the MCD diet only moderately decreased Oatp1a1 and induced both Oatp1a4 and Mrp4 gene expression. Whereas the MCD diet increased serum bile acid levels and alkaline phosphatase activity in both WT and H-RXRα-null mice, serum ALT levels were induced (2.9-fold) only in the H-RXRα-null mice. In conclusion, these data suggest a critical role for RXRα in hepatic fatty acid homeostasis and protection against MCD-induced hepatocyte injury. PMID:18952117

  8. Hepatic effects of a methionine-choline-deficient diet in hepatocyte RXR{alpha}-null mice

    SciTech Connect

    Gyamfi, Maxwell Afari; Tanaka, Yuji; He Lin; Klaassen, Curtis D.; Wan, Y.-J.Y.

    2009-01-15

    Retinoid X receptor-{alpha} (RXR{alpha}) is an obligate partner for several nuclear hormone receptors that regulate important physiological processes in the liver. In this study the impact of hepatocyte RXR{alpha} deficiency on methionine and choline deficient (MCD) diet-induced steatosis, oxidative stress, inflammation, and hepatic transporters gene expression were examined. The mRNA of sterol regulatory element-binding protein (SREBP)-regulated genes, important for lipid synthesis, were not altered in wild type (WT) mice, but were increased 2.0- to 5.4-fold in hepatocyte RXR{alpha}-null (H-RXR{alpha}-null) mice fed a MCD diet for 14 days. Furthermore, hepatic mRNAs and proteins essential for fatty acid {beta}-oxidation were not altered in WT mice, but were decreased in the MCD diet-fed H-RXR{alpha}-null mice, resulting in increased hepatic free fatty acid levels. Cyp2e1 enzyme activity and lipid peroxide levels were induced only in MCD-fed WT mice. In contrast, hepatic mRNA levels of pro-inflammatory factors were increased only in H-RXR{alpha}-null mice fed the MCD diet. Hepatic uptake transporters Oatp1a1 and Oatp1b2 mRNA levels were decreased in WT mice fed the MCD diet, whereas the efflux transporter Mrp4 was increased. However, in the H-RXR{alpha}-null mice, the MCD diet only moderately decreased Oatp1a1 and induced both Oatp1a4 and Mrp4 gene expression. Whereas the MCD diet increased serum bile acid levels and alkaline phosphatase activity in both WT and H-RXR{alpha}-null mice, serum ALT levels were induced (2.9-fold) only in the H-RXR{alpha}-null mice. In conclusion, these data suggest a critical role for RXR{alpha} in hepatic fatty acid homeostasis and protection against MCD-induced hepatocyte injury.

  9. Organic anion transporting polypeptide 1a1 null mice are sensitive to cholestatic liver injury.

    PubMed

    Zhang, Youcai; Csanaky, Iván L; Cheng, Xingguo; Lehman-McKeeman, Lois D; Klaassen, Curtis D

    2012-06-01

    Organic anion transporting polypeptide 1a1 (Oatp1a1) is predominantly expressed in livers of mice and is thought to transport bile acids (BAs) from blood into liver. Because Oatp1a1 expression is markedly decreased in mice after bile duct ligation (BDL). We hypothesized that Oatp1a1-null mice would be protected against liver injury during BDL-induced cholestasis due largely to reduced hepatic uptake of BAs. To evaluate this hypothesis, BDL surgeries were performed in both male wild-type (WT) and Oatp1a1-null mice. At 24 h after BDL, Oatp1a1-null mice showed higher serum alanine aminotransferase levels and more severe liver injury than WT mice, and all Oatp1a1-null mice died within 4 days after BDL, whereas all WT mice survived. At 24 h after BDL, surprisingly Oatp1a1-null mice had higher total BA concentrations in livers than WT mice, suggesting that loss of Oatp1a1 did not prevent BA accumulation in the liver. In addition, secondary BAs dramatically increased in serum of Oatp1a1-null BDL mice but not in WT BDL mice. Oatp1a1-null BDL mice had similar basolateral BA uptake (Na(+)-taurocholate cotransporting polypeptide and Oatp1b2) and BA-efflux (multidrug resistance-associated protein [Mrp]-3, Mrp4, and organic solute transporter α/β) transporters, as well as BA-synthetic enzyme (Cyp7a1) in livers as WT BDL mice. Hepatic expression of small heterodimer partner Cyp3a11, Cyp4a14, and Nqo1, which are target genes of farnesoid X receptor, pregnane X receptor, peroxisome proliferator-activated receptor alpha, and NF-E2-related factor 2, respectively, were increased in WT BDL mice but not in Oatp1a1-null BDL mice. These results demonstrate that loss of Oatp1a1 function exacerbates cholestatic liver injury in mice and suggest that Oatp1a1 plays a unique role in liver adaptive responses to obstructive cholestasis. PMID:22461449

  10. Abnormal Activation of BMP Signaling Causes Myopathy in Fbn2 Null Mice.

    PubMed

    Sengle, Gerhard; Carlberg, Valerie; Tufa, Sara F; Charbonneau, Noe L; Smaldone, Silvia; Carlson, Eric J; Ramirez, Francesco; Keene, Douglas R; Sakai, Lynn Y

    2015-06-01

    Fibrillins are large extracellular macromolecules that polymerize to form the backbone structure of connective tissue microfibrils. Mutations in the gene for fibrillin-1 cause the Marfan syndrome, while mutations in the gene for fibrillin-2 cause Congenital Contractural Arachnodactyly. Both are autosomal dominant disorders, and both disorders affect musculoskeletal tissues. Here we show that Fbn2 null mice (on a 129/Sv background) are born with reduced muscle mass, abnormal muscle histology, and signs of activated BMP signaling in skeletal muscle. A delay in Myosin Heavy Chain 8, a perinatal myosin, was found in Fbn2 null forelimb muscle tissue, consistent with the notion that muscle defects underlie forelimb contractures in these mice. In addition, white fat accumulated in the forelimbs during the early postnatal period. Adult Fbn2 null mice are already known to demonstrate persistent muscle weakness. Here we measured elevated creatine kinase levels in adult Fbn2 null mice, indicating ongoing cycles of muscle injury. On a C57Bl/6 background, Fbn2 null mice showed severe defects in musculature, leading to neonatal death from respiratory failure. These new findings demonstrate that loss of fibrillin-2 results in phenotypes similar to those found in congenital muscular dystrophies and that FBN2 should be considered as a candidate gene for recessive congenital muscular dystrophy. Both in vivo and in vitro evidence associated muscle abnormalities and accumulation of white fat in Fbn2 null mice with abnormally activated BMP signaling. Genetic rescue of reduced muscle mass and accumulation of white fat in Fbn2 null mice was accomplished by deleting a single allele of Bmp7. In contrast to other reports that activated BMP signaling leads to muscle hypertrophy, our findings demonstrate the exquisite sensitivity of BMP signaling to the fibrillin-2 extracellular environment during early postnatal muscle development. New evidence presented here suggests that fibrillin-2 can

  11. Increased Oxidative Stress Impairs Adipose Tissue Function in Sphingomyelin Synthase 1 Null Mice

    PubMed Central

    Nishimura, Naotaka; Gotoh, Tomomi; Watanabe, Ken; Ikeda, Kazutaka; Garan, Yohei; Taguchi, Ryo; Node, Koichi; Okazaki, Toshiro; Oike, Yuichi

    2013-01-01

    Sphingomyelin synthase 1 (SMS1) catalyzes the conversion of ceramide to sphingomyelin. Here, we found that SMS1 null mice showed lipodystrophic phenotype. Mutant mice showed up-regulation of plasma triglyceride concentrations accompanied by reduction of white adipose tissue (WAT) as they aged. Lipoprotein lipase (LPL) activity was severely reduced in mutant mice. In vivo analysis indicated that fatty acid uptake in WAT but not in liver decreased in SMS1 null compared to wild-type mice. In vitro analysis using cultured cell revealed that SMS1 depletion reduced fatty acid uptake. Proteins extracted from WAT of mutant mice were severely modified by oxidative stress, and up-regulation of mRNAs related to apoptosis, redox adjustment, mitochondrial stress response and mitochondrial biogenesis was observed. ATP content of WAT was reduced in SMS1 null mice. Blue native gel analysis indicated that accumulation of mitochondrial respiratory chain complexes was reduced. These results suggest that WAT of SMS1 null mice is severely damaged by oxidative stress and barely functional. Indeed, mutant mice treated with the anti-oxidant N-acetyl cysteine (NAC) showed partial recovery of lipodystrophic phenotypes together with normalized plasma triglyceride concentrations. Altogether, our data suggest that SMS1 is crucial to control oxidative stress in order to maintain WAT function. PMID:23593476

  12. Increased oxidative stress impairs adipose tissue function in sphingomyelin synthase 1 null mice.

    PubMed

    Yano, Masato; Yamamoto, Tadashi; Nishimura, Naotaka; Gotoh, Tomomi; Watanabe, Ken; Ikeda, Kazutaka; Garan, Yohei; Taguchi, Ryo; Node, Koichi; Okazaki, Toshiro; Oike, Yuichi

    2013-01-01

    Sphingomyelin synthase 1 (SMS1) catalyzes the conversion of ceramide to sphingomyelin. Here, we found that SMS1 null mice showed lipodystrophic phenotype. Mutant mice showed up-regulation of plasma triglyceride concentrations accompanied by reduction of white adipose tissue (WAT) as they aged. Lipoprotein lipase (LPL) activity was severely reduced in mutant mice. In vivo analysis indicated that fatty acid uptake in WAT but not in liver decreased in SMS1 null compared to wild-type mice. In vitro analysis using cultured cell revealed that SMS1 depletion reduced fatty acid uptake. Proteins extracted from WAT of mutant mice were severely modified by oxidative stress, and up-regulation of mRNAs related to apoptosis, redox adjustment, mitochondrial stress response and mitochondrial biogenesis was observed. ATP content of WAT was reduced in SMS1 null mice. Blue native gel analysis indicated that accumulation of mitochondrial respiratory chain complexes was reduced. These results suggest that WAT of SMS1 null mice is severely damaged by oxidative stress and barely functional. Indeed, mutant mice treated with the anti-oxidant N-acetyl cysteine (NAC) showed partial recovery of lipodystrophic phenotypes together with normalized plasma triglyceride concentrations. Altogether, our data suggest that SMS1 is crucial to control oxidative stress in order to maintain WAT function. PMID:23593476

  13. Spontaneous Skin Ulceration and Defective T Cell Function in CD18 Null Mice

    PubMed Central

    Scharffetter-Kochanek, Karin; Lu, Huifang; Norman, Keith; van Nood, Nicole; Munoz, Flor; Grabbe, Stephan; McArthur, Mark; Lorenzo, Isabel; Kaplan, Sheldon; Ley, Klaus; Wayne Smith, C.; Montgomery, Charles A.; Rich, Susan; Beaudet, Arthur L.

    1998-01-01

    A null mutation was prepared in the mouse for CD18, the β2 subunit of leukocyte integrins. Homozygous CD18 null mice develop chronic dermatitis with extensive facial and submandibular erosions. The phenotype includes elevated neutrophil counts, increased immunoglobulin levels, lymphadenopathy, splenomegaly, and abundant plasma cells in skin, lymph nodes, gut, and kidney. Very few neutrophils were found in spontaneously occurring skin lesions or with an induced toxic dermatitis. Intravital microscopy in CD18 null mice revealed a lack of firm neutrophil attachment to venules in the cremaster muscle in response to N-formyl- methionyl-leucyl-phenylalanine. A severe defect in T cell proliferation was found in the CD18 null mice when T cell receptors were stimulated either by staphylococcal enterotoxin A or by major histocompatibility complex alloantigens demonstrating a greater role of CD11/CD18 integrins in T cell responses than previously documented. The null mice are useful for delineating the functions of CD18 in vivo. PMID:9653089

  14. Spontaneous skin ulceration and defective T cell function in CD18 null mice.

    PubMed

    Scharffetter-Kochanek, K; Lu, H; Norman, K; van Nood, N; Munoz, F; Grabbe, S; McArthur, M; Lorenzo, I; Kaplan, S; Ley, K; Smith, C W; Montgomery, C A; Rich, S; Beaudet, A L

    1998-07-01

    A null mutation was prepared in the mouse for CD18, the beta2 subunit of leukocyte integrins. Homozygous CD18 null mice develop chronic dermatitis with extensive facial and submandibular erosions. The phenotype includes elevated neutrophil counts, increased immunoglobulin levels, lymphadenopathy, splenomegaly, and abundant plasma cells in skin, lymph nodes, gut, and kidney. Very few neutrophils were found in spontaneously occurring skin lesions or with an induced toxic dermatitis. Intravital microscopy in CD18 null mice revealed a lack of firm neutrophil attachment to venules in the cremaster muscle in response to N-formyl- methionyl-leucyl-phenylalanine. A severe defect in T cell proliferation was found in the CD18 null mice when T cell receptors were stimulated either by staphylococcal enterotoxin A or by major histocompatibility complex alloantigens demonstrating a greater role of CD11/CD18 integrins in T cell responses than previously documented. The null mice are useful for delineating the functions of CD18 in vivo. PMID:9653089

  15. Effects of space flight on the immunohistochemical demonstration of connexin 26 and connexin 43 in the postpartum uterus of rats

    NASA Technical Reports Server (NTRS)

    Burden, H. W.; Zary, J.; Alberts, J. R.

    1999-01-01

    The effect of space flight in a National Aeronautics and Space Administration shuttle was studied in pregnant rats. Rats were launched on day 11 of gestation and recovered on day 20 of gestation. Pregnancy was allowed to proceed to term and rats delivered vaginally on days 22-23, although flight animals required more labour contractions to complete the delivery process. Pups were placed with foster dams and connexin 26 and 43 were examined in the uterus of flight animals approximately 3 h after delivery. Space flight did not affect uterine connexin 26, localized primarily in epithelial cells of the endometrium, but decreased connexin 43, the major gap junction protein in the myometrium. It is suggested that decreased connexin 43 alters synchronization and coordination of labour contractions, resulting in a requirement for more contractions to complete the delivery process.

  16. Stimulation of Sigma-1 Receptor Ameliorates Depressive-like Behaviors in CaMKIV Null Mice.

    PubMed

    Moriguchi, Shigeki; Sakagami, Hiroyuki; Yabuki, Yasushi; Sasaki, Yuzuru; Izumi, Hisanao; Zhang, Chen; Han, Feng; Fukunaga, Kohji

    2015-12-01

    Sigma-1 receptor (Sig-1R) is a molecular chaperone regulating calcium efflux from the neuronal endoplasmic reticulum to the mitochondria. Calcium/calmodulin-dependent protein kinase IV (CaMKIV) null mice exhibit depressive-like behaviors and impaired neurogenesis as assessed by bromodeoxyuridine (BrdU) incorporation into newborn cells of the hippocampal dentate gyrus (DG). Here, we demonstrate that chronic stimulation of Sig-1R by treatment with the agonist SA4503 or the SSRI fluvoxamine for 14 days improves depressive-like behaviors in CaMKIV null mice. By contrast, treatment with paroxetine, which lacks affinity for Sig-1R, did not alter these behaviors. Reduced numbers of BrdU-positive cells and decreased brain-derived neurotrophic factor (BDNF) mRNA expression and protein kinase B (Akt; Ser-473) phosphorylation seen in the DG of CaMKIV null mice were significantly rescued by chronic Sig-1R stimulation. Interestingly, reduced ATP production observed in the DG of CaMKIV null mice was improved by chronic Sig-1R stimulation. Such stimulation also improved hippocampal long-term potentiation (LTP) induction and maintenance, which are impaired in the DG of CaMKIV null mice. LTP rescue was closely associated with both increases in calcium/calmodulin-dependent protein kinase II (CaMKII) autophosphorylation and GluA1 (Ser-831) phosphorylation. Taken together, Sig-1R stimulation by SA4503 or fluvoxamine treatment increased hippocampal neurogenesis, which is closely associated with amelioration of depressive-like behaviors in CaMKIV null mice. PMID:25316382

  17. Reduced infarct size in neuroglobin-null mice after experimental stroke in vivo

    PubMed Central

    2012-01-01

    Background Neuroglobin is considered to be a novel important pharmacological target in combating stroke and neurodegenerative disorders, although the mechanism by which this protection is accomplished remains an enigma. We hypothesized that if neuroglobin is directly involved in neuroprotection, then permanent cerebral ischemia would lead to larger infarct volumes in neuroglobin-null mice than in wild-type mice. Methods Using neuroglobin-null mice, we estimated the infarct volume 24 hours after permanent middle cerebral artery occlusion using Cavalieri’s Principle, and compared the infarct volume in neuroglobin-null and wild-type mice. Neuroglobin antibody staining was used to examine neuroglobin expression in the infarct area of wild-type mice. Results Infarct volumes 24 hours after permanent middle cerebral artery occlusion were significantly smaller in neuroglobin-null mice than in wild-types (p < 0.01). Neuroglobin immunostaining of the penumbra area revealed no visible up-regulation of neuroglobin protein in ischemic wild-type mice when compared to uninjured wild-type mice. In uninjured wild-type mice, neuroglobin protein was seen throughout cortical layer II and sparsely in layer V. In contrast, no neuroglobin-immunoreactive neurons were observed in the aforementioned layers of the ischemia injured cortical area, or in the surrounding penumbra of ischemic wild-type mice. This suggests no selective sparing of neuroglobin expressing neurons in ischemia. Conclusions Neuroglobin-deficiency resulted in reduced tissue infarction, suggesting that, at least at endogenous expression levels, neuroglobin in itself is non-protective against ischemic injury. PMID:22901501

  18. Alcohol-Induced Myocardial Fibrosis in Metallothionein-Null Mice

    PubMed Central

    Wang, Lipeng; Zhou, Zhanxiang; Saari, Jack T.; Kang, Y. James

    2005-01-01

    Alcohol-induced cardiomyopathy including fibrosis has been recognized clinically for a long time, but its pathogenesis is incompletely understood. Studies using experimental animals have not fully duplicated the pathological changes in humans, and animal models of alcoholic cardiac fibrosis are not available. In the present study, we have developed a mouse model in which cardiac hypertrophy and fibrosis were produced in metallothionein-knockout (MT-KO) mice fed an alcohol-containing liquid diet for 2 months. The same alcohol feeding did not produce cardiac fibrosis in the wild-type (WT) control mice, although there was no difference in the alcohol-induced heart hypertrophy between the WT controls and the MT-KO mice. Zinc supplementation prevented cardiac fibrosis but did not affect heart hypertrophy in the alcohol-fed MT-KO mice, suggesting a specific link between zinc homeostasis and cardiac fibrosis. Serum creatine phosphokinase activity was significantly higher in the alcohol-administered MT-KO mice than in the WT mice, and zinc supplementation decreased serum creatine phosphokinase activities and eliminated the difference between the groups. Thus, disturbance in zinc homeostasis due to the lack of MT associates with alcohol-induced cardiac fibrosis and more severe cardiac injury, making the MT-KO mouse model of alcohol-induced cardiac fibrosis a useful tool to investigate specific factors involved in the alcoholic cardiomyopathy. PMID:16049321

  19. Wound Healing Characteristics of ICAM-1 Null Mice Devoid of All Isoforms of ICAM-1

    PubMed Central

    Gay, Andre N.; Mushin, Oren P.; Lazar, David A.; Naik-Mathuria, Bindi J.; Yu, Ling; Gobin, Andre; Smith, C. Wayne; Olutoye, Oluyinka O.

    2011-01-01

    Background Intercellular Adhesion Molecule-1 (ICAM-1) permits leukocyte-endothelial adhesion and transmigration during inflammation. Membrane-bound ICAM-1 knockout mice have been used to understand this molecule’s role in wound-healing, but expressed spliced isoforms of ICAM-1 may have impacted results. We aimed to characterize wound-healing in an ICAM-1 null model devoid of all ICAM-1 isoforms. Methods Full-thickness 8-mm wounds were created on C57/BL6 wild-type (n=24) and ICAM-1 null (n=24) mice. Wound area was calculated using daily photographs. Histologic samples were harvested on post-operative Days 1,3,7, and 14. Wound margins were evaluated for mRNA expression of 13 inflammatory cytokines. A separate group of wild-type and ICAM-1 null mice (n=24) received full-thickness incisions with tensiometry measured at Day 14. Separately, complete blood counts were measured in unwounded wild-type (n=4) and ICAM-1 null mice (n=4). Results Wound-closure was significantly delayed in ICAM-1 null mice through Day 7 by gross and histologic measurement. mRNA expression of VEGF-A was increased in ICAM-1 null mice on Day 3, although no increase in VEGF-A was observed in the wound bed by immunohistochemistry. ICAM-1 null wounds demonstrated higher stiffness upon Day 14 tensiometry compared to the wild-type (1880 ± 926 kPa vs. 478 ± 117 kPa;p<0.01), and had higher counts of white blood cells (10,009 vs. 5,720 cells/microliter,p<0.05), neutrophils (2,130 vs. 630 cells/microliter,p<0.01), and lymphocytes (7,130 vs. 4,740 cells/microliter, p<0.05). Conclusions ICAM-1 null mice demonstrate delayed wound-healing and decreased wound elasticity compared to wild-type controls. This lag, however, was less than observed in earlier membrane-bound ICAM-1 knockouts, suggesting that other ICAM-1 isoforms may promote delayed wound-healing. PMID:21872884

  20. Aberrant connexin26 hemichannels underlying keratitis-ichthyosis-deafness syndrome are potently inhibited by mefloquine

    PubMed Central

    Levit, Noah A.; Sellitto, Caterina; Wang, Hong-Zhan; Li, Leping; Srinivas, Miduturu; Brink, Peter R.; White, Thomas W.

    2014-01-01

    Keratitis-ichthyosis-deafness (KID) syndrome is an ectodermal dysplasia caused by dominant mutations of connexin26 (Cx26). Loss of Cx26 function causes non-syndromic sensorineural deafness, without consequence in the epidermis. Functional analyses have revealed that a majority of KID-causing mutations confer a novel expansion of hemichannel activity, mediated by connexin channels in a non-junctional configuration. Inappropriate Cx26 hemichannel opening is hypothesized to compromise keratinocyte integrity and epidermal homeostasis. Pharmacological modulators of Cx26 are needed to assess the pathomechanistic involvement of hemichannels in the development of hyperkeratosis in KID syndrome. We have used electrophysiological assays to evaluate small molecule analogs of quinine for suppressive effects on aberrant hemichannel currents elicited by KID mutations. Here, we show that mefloquine inhibits several mutant hemichannel forms implicated in KID syndrome when expressed in Xenopus laevis oocytes (IC50≈16µM), using an extracellular divalent cation, zinc (Zn++), as a non-specific positive control for comparison (IC50≈3µM). Furthermore, we used freshly isolated transgenic keratinocytes to show that micromolar concentrations of mefloquine attenuated increased macroscopic membrane currents in primary mouse keratinocytes expressing human Cx26-G45E, a mutation causing a lethal form of KID syndrome. PMID:25229253

  1. The p.Cys169Tyr variant of connexin 26 is not a polymorphism

    PubMed Central

    Zonta, Francesco; Girotto, Giorgia; Buratto, Damiano; Crispino, Giulia; Morgan, Anna; Abdulhadi, Khalid; Alkowari, Moza; Badii, Ramin; Gasparini, Paolo; Mammano, Fabio

    2015-01-01

    Mutations in the GJB2 gene, which encodes the gap junction protein connexin 26 (Cx26), are the primary cause of hereditary prelingual hearing impairment. Here, the p.Cys169Tyr missense mutation of Cx26 (Cx26C169Y), previously classified as a polymorphism, has been identified as causative of severe hearing loss in two Qatari families. We have analyzed the effect of this mutation using a combination of confocal immunofluorescence microscopy and molecular dynamics simulations. At the cellular level, our results show that the mutant protein fails to form junctional channels in HeLa transfectants despite being correctly targeted to the plasma membrane. At the molecular level, this effect can be accounted for by disruption of the disulfide bridge that Cys169 forms with Cys64 in the wild-type structure (Cx26WT). The lack of the disulfide bridge in the Cx26C169Y protein causes a spatial rearrangement of two important residues, Asn176 and Thr177. In the Cx26WT protein, these residues play a crucial role in the intra-molecular interactions that permit the formation of an intercellular channel by the head-to-head docking of two opposing hemichannels resident in the plasma membrane of adjacent cells. Our results elucidate the molecular pathogenesis of hereditary hearing loss due to the connexin mutation and facilitate the understanding of its role in both healthy and affected individuals. PMID:25628337

  2. Downregulation of connexin 26 in human lung cancer is related to promoter methylation.

    PubMed

    Chen, Yuan; Hühn, Daniela; Knösel, Thomas; Pacyna-Gengelbach, Manuela; Deutschmann, Nicole; Petersen, Iver

    2005-01-01

    Cell-Cell communication via gap junctions plays a key role in carcinogenesis and in growth control. One of the gap junction proteins, Connexin 26 (Cx26) was considered as tumor suppressor in various cancers. In our study, the expression of Cx26 was analyzed in human lung cancer. The reduced mRNA expression was observed in 17 lung cancer cell lines examined by Northern blot analysis and RT-PCR. In 138 primary carcinomas comprising all subtypes analyzed by immunohistochemistry, 85 cases (62%) exhibited no expression of Cx26, whereas in other 53 cases the Cx26 staining was positive (38%). Additionally, an association between Cx26 protein expression and higher grading of tumors was found in whole tumor samples (p =0.028) but no statistically significant correlations could be observed with tumor stage, tumor size and node status. In squamous cell carcinoma, tumors with higher stage and grading were linked to higher expression of Cx26 (p = 0.015 and 0.017, respectively). To explore the mechanism responsible for the downregulation of Cx26, we treated 2 lung cancer cell lines H2170 and H226 with the demethylation agent 5-aza-2'-deoxycytidine and found the reexpression of Cx26 mRNA. Methylation status of these 2 cell lines was further analyzed by PCR amplification of bisulfite modified DNA and sequencing. A heterogeneous methylation pattern turned out. Our results suggest the inactivation of Cx26 in lung cancer may be explained by promoter methylation. PMID:15386363

  3. Aberrant connexin26 hemichannels underlying keratitis-ichthyosis-deafness syndrome are potently inhibited by mefloquine.

    PubMed

    Levit, Noah A; Sellitto, Caterina; Wang, Hong-Zhan; Li, Leping; Srinivas, Miduturu; Brink, Peter R; White, Thomas W

    2015-04-01

    Keratitis-ichthyosis-deafness (KID) syndrome is an ectodermal dysplasia caused by dominant mutations of connexin26 (Cx26). Loss of Cx26 function causes nonsyndromic sensorineural deafness, without consequence in the epidermis. Functional analyses have revealed that a majority of KID-causing mutations confer a novel expansion of hemichannel activity, mediated by connexin channels in a nonjunctional configuration. Inappropriate Cx26 hemichannel opening is hypothesized to compromise keratinocyte integrity and epidermal homeostasis. Pharmacological modulators of Cx26 are needed to assess the pathomechanistic involvement of hemichannels in the development of hyperkeratosis in KID syndrome. We have used electrophysiological assays to evaluate small-molecule analogs of quinine for suppressive effects on aberrant hemichannel currents elicited by KID mutations. Here, we show that mefloquine (MFQ) inhibits several mutant hemichannel forms implicated in KID syndrome when expressed in Xenopus laevis oocytes (IC50∼16 μM), using an extracellular divalent cation, zinc (Zn(++)), as a nonspecific positive control for comparison (IC50∼3 μM). Furthermore, we used freshly isolated transgenic keratinocytes to show that micromolar concentrations of MFQ attenuated increased macroscopic membrane currents in primary mouse keratinocytes expressing human Cx26-G45E, a mutation that causes a lethal form of KID syndrome. PMID:25229253

  4. Glomerular injury is exacerbated in diabetic integrin alpha1-null mice.

    PubMed

    Zent, R; Yan, X; Su, Y; Hudson, B G; Borza, D-B; Moeckel, G W; Qi, Z; Sado, Y; Breyer, M D; Voziyan, P; Pozzi, A

    2006-08-01

    Excessive glomerular collagen IV and reactive oxygen species (ROS) production are key factors in the development of diabetic nephropathy. Integrin alpha1beta1, the major collagen IV receptor, dowregulates collagen IV and ROS production, suggesting this integrin might determine the severity of diabetic nephropathy. To test this possibility, wild-type and integrin alpha1-null mice were rendered diabetic with streptozotocin (STZ) (100 mg/kg single intraperitoneal injection), after which glomerular filtration rate (GFR), glomerular collagen deposition, and glomerular basement membrane (GBM) thickening were evaluated. In addition, ROS and collagen IV production by mesangial cells as well as their proliferation was measured in vitro. Diabetic alpha1-null mice developed worse renal disease than diabetic wild-type mice. A significant increase in GFR was evident in the alpha1-null mice at 6 weeks after the STZ injection; it started to decrease by week 24 and reached levels of non-diabetic mice by week 36. In contrast, GFR only increased in wild-type mice at week 12 and its elevation persisted throughout the study. Diabetic mutant mice also showed increased glomerular deposition of collagen IV and GBM thickening compared to diabetic wild-type mice. Primary alpha1-null mesangial cells exposed to high glucose produced more ROS than wild-type cells, which led to decreased proliferation and increased collagen IV synthesis, thus mimicking the in vivo finding. In conclusion, this study suggests that lack of integrin alpha1beta1 exacerbates the glomerular injury in a mouse model of diabetes by modulating GFR, ROS production, cell proliferation, and collagen deposition. PMID:16775606

  5. Impaired capsule formation of tumors in periostin-null mice

    SciTech Connect

    Shimazaki, Masashi; Kudo, Akira

    2008-03-21

    Being a secreted protein, periostin is a multifunctional matricellular glycoprotein. In vitro, periostin has the ability to promote the proliferation and migration of fibroblasts. Previously, it was demonstrated that periostin is mainly produced by cancer-associated fibroblasts or tumor stromal cells. In the present study, we show that periostin regulates capsule formation in a positive manner and inhibits tumor growth. Consistent with a previous finding, several tumor cell lines did not exhibit expression of periostin in vitro or in vivo; and the growth of tumors that had been allografted into periostin -/- mice was significantly accelerated compared with that of the same kind of tumors grafted into periostin +/+ mice. Immunostaining and biochemical analyses revealed that mature collagen was detected abundantly in the capsules and interstitium of the wild-type-grafted tumors but not in those of the periostin -/- grafted tumors. Moreover, the number of activated tumor stromal cells was decreased significantly in the periostin -/- grafted tumors. Our studies suggest that host-derived periostin negatively regulates tumor growth by promoting capsule formation and by mediating changes in the deposition and organization of the tumor microenvironment coordinated by periostin-producing stromal cells.

  6. Vitamin E Status and Metabolism in Adult and Aged Aryl Hydrocarbon Receptor Null Mice

    PubMed Central

    Traber, Maret G.; Mustacich, Debbie J.; Sullivan, Laura C.; Leonard, Scott W.; Ahern-Rindell, Amelia; Kerkvliet, Nancy

    2009-01-01

    The aryl hydrocarbon receptor (AhR) is involved in regulation of mechanisms for detoxification of xenobiotics, as well as vitamin A metabolism. Vitamin E is a fat-soluble nutrient whose metabolism is initialized via the cytochrome P450 system. Thus, AhR absence could alter hepatic regulation of α-tocopherol metabolism. To test this hypothesis, we assessed vitamin E status in adult (2–5 m) and old (21–22 m), wildtype and AhR-null mice. Plasma α-tocopherol concentrations in AhR null mice (2.3 ± 1.2 μmol/L, n= 19) were lower than those of wildtype mice (3.2 ± 1.2, n=17, P=0.0131); those in old mice (3.2 ± 1.2, n= 20) were higher than those of adults (2.2 ± 1.0, n=16, p=0.0075). Hepatic α-tocopherol concentrations were not different between genotypes, but were nearly double in old (32 ± 8 nmol/g, n=20) as compared with adult mice (17 ± 2, n=16, p<0.0001). Hepatic Cyp3a concentrations in AhR-null mice were greater than those in wildtypes (p=0.0011). Genotype (p=0.0047), sex (p<0.0001) and age (p<0.0001) were significant modifiers of liver α-tocopherol metabolite (α-CEHC) concentrations. In general, Cyp3a concentrations correlated with hepatic α-tocopherol (r= 0.3957, p<0.05) and α-CEHC (r=0.4260, p<0.05) concentrations. Since there were no significant genotype differences in the hepatic α- or γ-tocopherol concentrations, AhR null mice did not have dramatically altered vitamin E metabolism. Since they did have higher hepatic α-CEHC concentrations, these data suggest metabolism was up-regulated in the AhR null mice in order to maintain the hepatic tocopherol concentrations similar to those of wildtypes. PMID:20153623

  7. Altered astrocyte morphology and vascular development in dystrophin-Dp71-null mice.

    PubMed

    Giocanti-Auregan, Audrey; Vacca, Ophélie; Bénard, Romain; Cao, Sijia; Siqueiros, Lourdes; Montañez, Cecilia; Paques, Michel; Sahel, José-Alain; Sennlaub, Florian; Guillonneau, Xavier; Rendon, Alvaro; Tadayoni, Ramin

    2016-05-01

    Understanding retinal vascular development is crucial because many retinal vascular diseases such as diabetic retinopathy (in adults) or retinopathy of prematurity (in children) are among the leading causes of blindness. Given the localization of the protein Dp71 around the retinal vessels in adult mice and its role in maintaining retinal homeostasis, the aim of this study was to determine if Dp71 was involved in astrocyte and vascular development regulation. An experimental study in mouse retinas was conducted. Using a dual immunolabeling with antibodies to Dp71 and anti-GFAP for astrocytes on retinal sections and isolated astrocytes, it was found that Dp71 was expressed in wild-type (WT) mouse astrocytes from early developmental stages to adult stage. In Dp71-null mice, a reduction in GFAP-immunopositive astrocytes was observed as early as postnatal day 6 (P6) compared with WT mice. Using real-time PCR, it was showed that Dp71 mRNA was stable between P1 and P6, in parallel with post-natal vascular development. Regarding morphology in Dp71-null and WT mice, a significant decrease in overall astrocyte process number in Dp71-null retinas at P6 to adult age was found. Using fluorescence-conjugated isolectin Griffonia simplicifolia on whole mount retinas, subsequent delay of developing vascular network at the same age in Dp71-null mice was found. An evidence that the Dystrophin Dp71, a membrane-associated cytoskeletal protein and one of the smaller Duchenne muscular dystrophy gene products, regulates astrocyte morphology and density and is associated with subsequent normal blood vessel development was provided. GLIA 2016;64:716-729. PMID:26711882

  8. Orexin Receptor Antagonism Improves Sleep and Reduces Seizures in Kcna1-null Mice

    PubMed Central

    Roundtree, Harrison M.; Simeone, Timothy A.; Johnson, Chaz; Matthews, Stephanie A.; Samson, Kaeli K.; Simeone, Kristina A.

    2016-01-01

    Study Objective: Comorbid sleep disorders occur in approximately one-third of people with epilepsy. Seizures and sleep disorders have an interdependent relationship where the occurrence of one can exacerbate the other. Orexin, a wake-promoting neuropeptide, is associated with sleep disorder symptoms. Here, we tested the hypothesis that orexin dysregulation plays a role in the comorbid sleep disorder symptoms in the Kcna1-null mouse model of temporal lobe epilepsy. Methods: Rest-activity was assessed using infrared beam actigraphy. Sleep architecture and seizures were assessed using continuous video-electroencephalography-electromyography recordings in Kcna1-null mice treated with vehicle or the dual orexin receptor antagonist, almorexant (100 mg/kg, intraperitoneally). Orexin levels in the lateral hypothalamus/perifornical region (LH/P) and hypothalamic pathology were assessed with immunohistochemistry and oxygen polarography. Results: Kcna1-null mice have increased latency to rapid eye movement (REM) sleep onset, sleep fragmentation, and number of wake epochs. The numbers of REM and non-REM (NREM) sleep epochs are significantly reduced in Kcna1-null mice. Severe seizures propagate to the wake-promoting LH/P where injury is apparent (indicated by astrogliosis, blood-brain barrier permeability, and impaired mitochondrial function). The number of orexin-positive neurons is increased in the LH/P compared to wild-type LH/P. Treatment with a dual orexin receptor antagonist significantly increases the number and duration of NREM sleep epochs and reduces the latency to REM sleep onset. Further, almorexant treatment reduces the incidence of severe seizures and overall seizure burden. Interestingly, we report a significant positive correlation between latency to REM onset and seizure burden in Kcna1-null mice. Conclusion: Dual orexin receptor antagonists may be an effective sleeping aid in epilepsy, and warrants further study on their somnogenic and ant-seizure effects in

  9. Leucine supplementation via drinking water reduces atherosclerotic lesions in apoE null mice

    PubMed Central

    Zhao, Yang; Dai, Xiao-yan; Zhou, Zhou; Zhao, Ge-xin; Wang, Xian; Xu, Ming-jiang

    2016-01-01

    Aim: Recent evidence suggests that the essential amino acid leucine may be involved in systemic cholesterol metabolism. In this study, we investigated the effects of leucine supplementation on the development of atherosclerosis in apoE null mice. Methods: ApoE null mice were fed with chow supplemented with leucine (1.5% w/v) in drinking water for 8 week. Aortic atherosclerotic lesions were examined using Oil Red O staining. Plasma lipoprotein-cholesterol levels were measured with fast protein liquid chromatography. Hepatic gene expression was detected using real-time PCR and Western blot analyses. Results: Leucine supplementation resulted in 57.6% reduction of aortic atherosclerotic lesion area in apoE null mice, accompanied by 41.2% decrease of serum LDL-C levels and 40.2% increase of serum HDL-C levels. The body weight, food intake and blood glucose level were not affected by leucine supplementation. Furthermore, leucine supplementation increased the expression of Abcg5 and Abcg8 (that were involved in hepatic cholesterol efflux) by 1.28- and 0.86-fold, respectively, and significantly increased their protein levels. Leucine supplementation also increased the expression of Srebf1, Scd1 and Pgc1b (that were involved in hepatic triglyceride metabolism) by 3.73-, 1.35- and 1.71-fold, respectively. Consequently, leucine supplementation resulted in 51.77% reduction of liver cholesterol content and 2.2-fold increase of liver triglyceride content. Additionally, leucine supplementation did not affect the serum levels of IL-6, IFN-γ, TNF-α, IL-10 and IL-12, but markedly decreased the serum level of MCP-1. Conclusion: Leucine supplementation effectively attenuates atherosclerosis in apoE null mice by improving the plasma lipid profile and reducing systemic inflammation. PMID:26687933

  10. Otx1 null mutant mice show partial segregation of sensory epithelia comparable to lamprey ears

    NASA Technical Reports Server (NTRS)

    Fritzsch, B.; Signore, M.; Simeone, A.

    2001-01-01

    We investigated the development of inner ear innervation in Otx1 null mutants, which lack a horizontal canal, between embryonic day 12 (E12) and postnatal day 7 (P7) with DiI and immunostaining for acetylated tubulin. Comparable to control animals, horizontal crista-like fibers were found to cross over the utricle in Otx1 null mice. In mutants these fibers extend toward an area near the endolymphatic duct, not to a horizontal crista. Most Otx1 null mutants had a small patch of sensory hair cells at this position. Measurement of the area of the utricular macula suggested it to be enlarged in Otx1 null mutants. We suggest that parts of the horizontal canal crista remain incorporated in the utricular sensory epithelium in Otx1 null mutants. Other parts of the horizontal crista appear to be variably segregated to form the isolated patch of hair cells identifiable by the unique fiber trajectory as representing the horizontal canal crista. Comparison with lamprey ear innervation reveals similarities in the pattern of innervation with the dorsal macula, a sensory patch of unknown function. SEM data confirm that all foramina are less constricted in Otx1 null mutants. We propose that Otx1 is not directly involved in sensory hair cell formation of the horizontal canal but affects the segregation of the horizontal canal crista from the utricle. It also affects constriction of the two main foramina in the ear, but not their initial formation. Otx1 is thus causally related to horizontal canal morphogenesis as well as morphogenesis of these foramina.

  11. Pituitary tumor transforming gene-null male mice exhibit impaired pancreatic beta cell proliferation and diabetes

    PubMed Central

    Wang, Zhiyong; Moro, Enrico; Kovacs, Kalman; Yu, Run; Melmed, Shlomo

    2003-01-01

    The mammalian securin, pituitary tumor transforming gene (PTTG), regulates sister chromatid separation during mitosis. Mice or cell lines deficient in PTTG expression, however, are surprisingly viable. Here we show that PTTG disruption in mice (PTTG−/−) severely impairs glucose homeostasis leading to diabetes during late adulthood, especially in males associated with nonautoimmune insulinopenia and reversed alpha/beta cell ratio. Islet beta cell mass in PTTG−/− mice was already diminished before development of frank diabetes and only increased minimally during growth. BrdUrd incorporation of islet cells in PTTG-null mice was ≈65% lower (P < 0.005) than in the WT pancreas, whereas apoptosis rates were similar. PTTG−/− beta cells had pleiotropic nuclei, suggesting defects in cell division. The results indicated that securin is indispensable for normal pancreatic beta cell proliferation. PMID:12626748

  12. Impaired spare respiratory capacity in cortical synaptosomes from Sod2 null mice

    PubMed Central

    Flynn, James M.; Choi, Sung W.; Day, Nicholas U.; Gerencser, Akos A.; Hubbard, Alan; Melov, Simon

    2011-01-01

    Pre-synaptic nerve terminals require high levels of ATP for the maintenance of synaptic function. Failure of synaptic mitochondria to generate adequate ATP has been implicated as a causative event preceding loss of synaptic networks in neurodegenerative disease. Endogenous oxidative stress has often been postulated as an etiological basis for this pathology, but has been difficult to test in vivo. Inactivation of the superoxide dismutase gene (Sod2) encoding the chief defense enzyme against mitochondrial superoxide radicals results in neonatal lethality. However, intervention with an SOD mimetic extends the lifespan of this model, and uncovers a neurodegenerative phenotype providing a unique model for the examination of in vivo oxidative stress. We present here studies on synaptic termini isolated from the frontal cortex of Sod2 null mice demonstrating impaired bioenergetic function as a result of mitochondrial oxidative stress. Cortical synaptosomes from Sod2 null mice demonstrate a severe decline in mitochondrial spare respiratory capacity to physiological demand induced by mitochondrial respiratory chain uncoupling with FCCP or plasma membrane depolarization induced by 4-aminopyridine treatment. However, Sod2 null animals compensate for impaired oxidative metabolism in part by Pasteur effect allowing for normal neurotransmitter release at the synapse, setting up a potentially detrimental energetic paradigm. The results of this study demonstrate that high throughput respirometry is a facile method for analyzing specific regions of the brain in transgenic models, and can uncover bioenergetic deficits in subcellular regions due to endogenous oxidative stress. PMID:21215798

  13. Enhanced Energy Expenditure, Glucose Utilization, and Insulin Sensitivity in VAMP8 Null Mice

    PubMed Central

    Zong, Haihong; Wang, Cheng-Chun; Vaitheesvaran, Bhavapriya; Kurland, Irwin J.; Hong, Wanjin; Pessin, Jeffrey E.

    2011-01-01

    OBJECTIVE Previous studies have demonstrated that the VAMP8 protein plays a complex role in the control of granule secretion, transport vesicle trafficking, phagocytosis, and endocytosis. The present study was aimed to investigate the role of VAMP8 in mediating GLUT4 trafficking and therefore insulin action in mice. RESEARCH DESIGN AND METHODS Physiological parameters were measured using Oxymax indirect calorimetry system in 12-week-old VAMP8 null mice. Dynamic analysis of glucose homeostasis was assessed using euglycemic–hyperinsulinemic clamp coupled with tracer radioactively labeled 2-deoxyglucose. Insulin stimulated GLUT4 protein expressions on muscle cell surface were examined by immunofluorescence microscopy. RESULTS VAMP8 null mice display reduced adiposity with increased energy expenditure despite normal food intake and reduced spontaneous locomotor activity. In parallel, the VAMP8 null mice also had fasting hypoglycemia (84 ± 11 vs. 115 ± 4) and enhanced glucose tolerance with increased insulin sensitivity due to increases in both basal and insulin-stimulated glucose uptake in skeletal muscle (0.19 ± 0.04 vs. 0.09 ± 0.01 mmol/kg/min during basal, 0.6 ± 0.04 vs. 0.31 ± 0.06 mmol/kg/min during clamp in red-gastrocnemius muscle, P < 0.05). Consistent with a role for VAMP8 in the endocytosis of the insulin-responsive GLUT4, sarcolemma GLUT4 protein levels were increased in both the basal and insulin-stimulated states without any significant change in the total amount of GLUT4 protein or related facilitative glucose transporters present in skeletal muscle, GLUT1, GLUT3, and GLUT11. CONCLUSIONS These data demonstrate that, in the absence of VAMP8, the relative subcellular distribution of GLUT4 is altered, resulting in increased sarcolemma levels that can account for increased glucose clearance and insulin sensitivity. PMID:20876717

  14. Metabolic and Phenotypic Differences between Mice Producing a Werner Syndrome Helicase Mutant Protein and Wrn Null Mice.

    PubMed

    Aumailley, Lucie; Garand, Chantal; Dubois, Marie Julie; Johnson, F Brad; Marette, André; Lebel, Michel

    2015-01-01

    Werner syndrome (WS) is a premature aging disorder caused by mutations in a RecQ-family DNA helicase, WRN. Mice lacking part of the helicase domain of the WRN orthologue exhibit many phenotypic features of WS, including metabolic abnormalities and a shorter mean life span. In contrast, mice lacking the entire Wrn protein (i.e. Wrn null mice) do not exhibit a premature aging phenotype. In this study, we used a targeted mass spectrometry-based metabolomic approach to identify serum metabolites that are differentially altered in young Wrn helicase mutant and Wrn null mice. An antibody-based quantification of 43 serum cytokines and markers of cardiovascular disease risk complemented this study. We found that Wrn helicase mutants exhibited elevated and decreased levels, respectively, of the anti-inflammatory cytokine IL-10 and the pro-inflammatory cytokine IL-18. Wrn helicase mutants also exhibited an increase in serum hydroxyproline and plasminogen activator inhibitor-1, markers of extracellular matrix remodeling of the vascular system and inflammation in aging. We also observed an abnormal increase in the ratio of very long chain to short chain lysophosphatidylcholines in the Wrn helicase mutants underlying a peroxisome perturbation in these mice. Remarkably, the Wrn mutant helicase protein was mislocalized to the endoplasmic reticulum and the peroxisomal fractions in liver tissues. Additional analyses with mouse embryonic fibroblasts indicated a severe defect of the autophagy flux in cells derived from Wrn helicase mutants compared to wild type and Wrn null animals. These results indicate that the deleterious effects of the helicase-deficient Wrn protein are mediated by the dysfunction of several cellular organelles. PMID:26447695

  15. Metabolic and Phenotypic Differences between Mice Producing a Werner Syndrome Helicase Mutant Protein and Wrn Null Mice

    PubMed Central

    Aumailley, Lucie; Garand, Chantal; Dubois, Marie Julie; Johnson, F. Brad; Marette, André; Lebel, Michel

    2015-01-01

    Werner syndrome (WS) is a premature aging disorder caused by mutations in a RecQ-family DNA helicase, WRN. Mice lacking part of the helicase domain of the WRN orthologue exhibit many phenotypic features of WS, including metabolic abnormalities and a shorter mean life span. In contrast, mice lacking the entire Wrn protein (i.e. Wrn null mice) do not exhibit a premature aging phenotype. In this study, we used a targeted mass spectrometry-based metabolomic approach to identify serum metabolites that are differentially altered in young Wrn helicase mutant and Wrn null mice. An antibody-based quantification of 43 serum cytokines and markers of cardiovascular disease risk complemented this study. We found that Wrn helicase mutants exhibited elevated and decreased levels, respectively, of the anti-inflammatory cytokine IL-10 and the pro-inflammatory cytokine IL-18. Wrn helicase mutants also exhibited an increase in serum hydroxyproline and plasminogen activator inhibitor-1, markers of extracellular matrix remodeling of the vascular system and inflammation in aging. We also observed an abnormal increase in the ratio of very long chain to short chain lysophosphatidylcholines in the Wrn helicase mutants underlying a peroxisome perturbation in these mice. Remarkably, the Wrn mutant helicase protein was mislocalized to the endoplasmic reticulum and the peroxisomal fractions in liver tissues. Additional analyses with mouse embryonic fibroblasts indicated a severe defect of the autophagy flux in cells derived from Wrn helicase mutants compared to wild type and Wrn null animals. These results indicate that the deleterious effects of the helicase-deficient Wrn protein are mediated by the dysfunction of several cellular organelles. PMID:26447695

  16. Chronic Toxoplasma gondii in Nurr1-null heterozygous mice exacerbates elevated open field activity.

    PubMed

    Eells, Jeffrey B; Varela-Stokes, Andrea; Guo-Ross, Shirley X; Kummari, Evangel; Smith, Holly M; Cox, Erin; Lindsay, David S

    2015-01-01

    Latent infection with Toxoplasma gondii is common in humans (approximately 30% of the global population) and is a significant risk factor for schizophrenia. Since prevalence of T. gondii infection is far greater than prevalence of schizophrenia (0.5-1%), genetic risk factors are likely also necessary to contribute to schizophrenia. To test this concept in an animal model, Nurr1-null heterozygous (+/-) mice and wild-type (+/+) mice were evaluate using an emergence test, activity in an open field and with a novel object, response to bobcat urine and prepulse inhibition of the acoustic startle response (PPI) prior to and 6 weeks after infection with T. gondii. In the emergence test, T. gondii infection significantly decreased the amount of time spent in the cylinder. Toxoplasma gondii infection significantly elevated open field activity in both +/+ and +/- mice but this increase was significantly exacerbated in +/- mice. T. gondii infection reduced PPI in male +/- mice but this was not statistically significant. Aversion to bobcat urine was abolished by T. gondii infection in +/+ mice. In female +/- mice, aversion to bobcat urine remained after T. gondii infection while the male +/- mice showed no aversion to bobcat urine. Antibody titers of infected mice were a critical variable associated with changes in open field activity, such that an inverted U shaped relationship existed between antibody titers and the percent change in open field activity with a significant increase in activity at low and medium antibody titers but no effect at high antibody titers. These data demonstrate that the Nurr1 +/- genotype predisposes mice to T. gondii-induced alterations in behaviors that involve dopamine neurotransmission and are associated with symptoms of schizophrenia. We propose that these alterations in murine behavior were due to further exacerbation of the altered dopamine neurotransmission in Nurr1 +/- mice. PMID:25855987

  17. Chronic Toxoplasma gondii in Nurr1-Null Heterozygous Mice Exacerbates Elevated Open Field Activity

    PubMed Central

    Eells, Jeffrey B.; Varela-Stokes, Andrea; Guo-Ross, Shirley X.; Kummari, Evangel; Smith, Holly M.; Cox, Erin; Lindsay, David S.

    2015-01-01

    Latent infection with Toxoplasma gondii is common in humans (approximately 30% of the global population) and is a significant risk factor for schizophrenia. Since prevalence of T. gondii infection is far greater than prevalence of schizophrenia (0.5-1%), genetic risk factors are likely also necessary to contribute to schizophrenia. To test this concept in an animal model, Nurr1-null heterozygous (+/-) mice and wild-type (+/+) mice were evaluate using an emergence test, activity in an open field and with a novel object, response to bobcat urine and prepulse inhibition of the acoustic startle response (PPI) prior to and 6 weeks after infection with T. gondii. In the emergence test, T. gondii infection significantly decreased the amount of time spent in the cylinder. Toxoplasma gondii infection significantly elevated open field activity in both +/+ and +/- mice but this increase was significantly exacerbated in +/- mice. T. gondii infection reduced PPI in male +/- mice but this was not statistically significant. Aversion to bobcat urine was abolished by T. gondii infection in +/+ mice. In female +/- mice, aversion to bobcat urine remained after T. gondii infection while the male +/- mice showed no aversion to bobcat urine. Antibody titers of infected mice were a critical variable associated with changes in open field activity, such that an inverted U shaped relationship existed between antibody titers and the percent change in open field activity with a significant increase in activity at low and medium antibody titers but no effect at high antibody titers. These data demonstrate that the Nurr1 +/- genotype predisposes mice to T. gondii-induced alterations in behaviors that involve dopamine neurotransmission and are associated with symptoms of schizophrenia. We propose that these alterations in murine behavior were due to further exacerbation of the altered dopamine neurotransmission in Nurr1 +/- mice. PMID:25855987

  18. Enhanced ethanol catabolism in orphan nuclear receptor SHP-null mice.

    PubMed

    Park, Jung Eun; Lee, Mikang; Mifflin, Ryan; Lee, Yoon Kwang

    2016-05-15

    Deficiency of the orphan nuclear hormone receptor small heterodimer partner (SHP, NR0B2) protects mice from diet-induced hepatic steatosis, in part, via repression of peroxisome proliferator-activated receptor (PPAR)-γ2 (Pparg2) gene expression. Alcoholic fatty liver diseases (AFLD) share many common pathophysiological features with non-AFLD. To study the role of SHP and PPARγ2 in AFLD, we used a strategy of chronic ethanol feeding plus a single binge ethanol feeding to challenge wild-type (WT) and SHP-null (SHP(-/-)) mice with ethanol. The ethanol feeding induced liver fat accumulation and mRNA expression of hepatic Pparg2 in WT mice, which suggests that a high level of PPARγ2 is a common driving force for fat accumulation induced by ethanol or a high-fat diet. Interestingly, ethanol-fed SHP(-/-) mice displayed hepatic fat accumulation similar to that of ethanol-fed WT mice, even though their Pparg2 expression level remained lower. Mortality of SHP(-/-) mice after ethanol binge feeding was significantly reduced and their acetaldehyde dehydrogenase (Aldh2) mRNA level was higher than that of their WT counterparts. After an intoxicating dose of ethanol, SHP(-/-) mice exhibited faster blood ethanol clearance and earlier wake-up time than WT mice. Higher blood acetate, the end product of ethanol metabolism, and lower acetaldehyde levels were evident in the ethanol-challenged SHP(-/-) than WT mice. Ethanol-induced inflammatory responses and lipid peroxidation were also lower in SHP(-/-) mice. The current data show faster ethanol catabolism and extra fat storage through conversion of acetate to acetyl-CoA before its release into the circulation in this ethanol-feeding model in SHP(-/-) mice. PMID:26968209

  19. Impaired Thermogenesis and a Molecular Signature for Brown Adipose Tissue in Id2 Null Mice.

    PubMed

    Zhou, Peng; Robles-Murguia, Maricela; Mathew, Deepa; Duffield, Giles E

    2016-01-01

    Inhibitor of DNA binding 2 (ID2) is a helix-loop-helix transcriptional repressor rhythmically expressed in many adult tissues. Our previous studies have demonstrated that Id2 null mice have sex-specific elevated glucose uptake in brown adipose tissue (BAT). Here we further explored the role of Id2 in the regulation of core body temperature over the circadian cycle and the impact of Id2 deficiency on genes involved in insulin signaling and adipogenesis in BAT. We discovered a reduced core body temperature in Id2-/- mice. Moreover, in Id2-/- BAT, 30 genes including Irs1, PPARs, and PGC-1s were identified as differentially expressed in a sex-specific pattern. These data provide valuable insights into the impact of Id2 deficiency on energy homeostasis of mice in a sex-specific manner. PMID:27144179

  20. Impaired Thermogenesis and a Molecular Signature for Brown Adipose Tissue in Id2 Null Mice

    PubMed Central

    Zhou, Peng; Robles-Murguia, Maricela; Mathew, Deepa; Duffield, Giles E.

    2016-01-01

    Inhibitor of DNA binding 2 (ID2) is a helix-loop-helix transcriptional repressor rhythmically expressed in many adult tissues. Our previous studies have demonstrated that Id2 null mice have sex-specific elevated glucose uptake in brown adipose tissue (BAT). Here we further explored the role of Id2 in the regulation of core body temperature over the circadian cycle and the impact of Id2 deficiency on genes involved in insulin signaling and adipogenesis in BAT. We discovered a reduced core body temperature in Id2−/− mice. Moreover, in Id2−/− BAT, 30 genes including Irs1, PPARs, and PGC-1s were identified as differentially expressed in a sex-specific pattern. These data provide valuable insights into the impact of Id2 deficiency on energy homeostasis of mice in a sex-specific manner. PMID:27144179

  1. Seizure phenotypes, periodicity, and sleep-wake pattern of seizures in Kcna-1 null mice.

    PubMed

    Wright, Samantha; Wallace, Eli; Hwang, Youngdeok; Maganti, Rama

    2016-02-01

    This study was undertaken to describe seizure phenotypes, natural progression, sleep-wake patterns, as well as periodicity of seizures in Kcna-1 null mutant mice. These mice were implanted with epidural electroencephalography (EEG) and electromyography (EMG) electrodes, and simultaneous video-EEG recordings were obtained while animals were individually housed under either diurnal (LD) condition or constant darkness (DD) over ten days of recording. The video-EEG data were analyzed to identify electrographic and behavioral phenotypes and natural progression and to examine the periodicity of seizures. Sleep-wake patterns were analyzed to understand the distribution and onset of seizures across the sleep-wake cycle. Four electrographically and behaviorally distinct seizure types were observed. Regardless of lighting condition that animals were housed in, Kcna-1 null mice initially expressed only a few of the most severe seizure types that progressively increased in frequency and decreased in seizure severity. In addition, a circadian periodicity was noted, with seizures peaking in the first 12h of the Zeitgeber time (ZT) cycle, regardless of lighting conditions. Interestingly, seizure onset differed between lighting conditions where more seizures arose out of sleep in LD conditions, whereas under DD conditions, the majority occurred out of the wakeful state. We suggest that this model be used to understand the circadian pattern of seizures as well as the pathophysiological implications of sleep and circadian disturbances in limbic epilepsies. PMID:26724401

  2. Fibroblast Growth Factor 21-Null Mice Do Not Exhibit an Impaired Response to Fasting

    PubMed Central

    Antonellis, Patrick Joseph; Hayes, Meghan Patricia; Adams, Andrew Charles

    2016-01-01

    Fibroblast growth factor 21 (FGF21) is a pleotropic metabolic regulator, expression of which is elevated during fasting. To this end, the precise role played by FGF21 in the biology of fasting has been the subject of several recent studies, which have demonstrated contributions to the regulation of both lipid and carbohydrate metabolism. In the present study, we compared wild-type (WT) and FGF21-null (FGF21KO) mice, demonstrating that, despite the significant induction of FGF21 during fasting in the WT animals, our strain of FGF21-null mice exhibits only limited impairments in their adaptation to nutrient deprivation. Specifically, fasted FGF21KO mice display a mild attenuation of gluconeogenic transcriptional induction in the liver accompanied by partially blunted glucose production in response to a pyruvate challenge. Furthermore, FGF21KO mice displayed only minor impairments in lipid metabolism in the fasted state, limited to accumulation of hepatic triglycerides and a reduction in expression of genes associated with fatty acid oxidation. To address the possibility of compensation to germline deletion of FGF21, we further interrogated the role of endogenous FGF21 via acute pharmacological blockade of FGF21 signaling. At the transcriptional level, we show that FGF21 signaling is required for full induction of gluconeogenic and oxidative genes in the liver. However, corroborating our findings in FGF21KO mice, pharmacological blockade of the FGF21 axis did not profoundly disrupt the physiological response to fasting. Taken as a whole, these data demonstrate that, while FGF21 is partially required for appropriate gene expression during the fed to fasted transition, its absence does not significantly impact the downstream physiology of the fasted state. PMID:27445980

  3. ORAL EXPOSURE TO ACROLEIN EXACERBATES ATHEROSCLEROSIS IN APO E-NULL MICE

    PubMed Central

    Srivastava, Sanjay; Sithu, Srinivas D.; Vladykovskaya, Elena; Haberzettl, Petra; Hoetker, David J.; Siddiqui, Maqsood A.; Conklin, Daniel J.; D'Souza, Stanley E.; Bhatnagar, Aruni

    2011-01-01

    Background Acrolein is a dietary aldehyde that is present in high concentrations in alcoholic beverages and foods including cheese, donuts and coffee. It is also abundant in tobacco smoke, automobile exhaust and industrial waste and is generated in vivo during inflammation and oxidative stress. Objectives The goal of this study was to examine the effects of dietary acrolein on atherosclerosis. Methods Eight-week old male apoE-null mice were gavage-fed acrolein (2.5 mg/kg/day) for 8 weeks. Atherosclerotic lesion formation and composition and plasma lipids and platelet factor 4 (PF4) levels were measured. Effects of acrolein and PF4 on endothelial cell function was measured in vitro. Results Acrolein feeding increased the concentration of cholesterol in the plasma. NMR analysis of the lipoproteins showed that acrolein feeding increased the abundance of small and medium VLDL particles. Acrolein feeding also increased atherosclerotic lesion formation in the aortic valve and the aortic arch. Immunohistochemical analysis showed increased macrophage accumulation in the lesions of acrolein-fed mice. Plasma PF4 levels and accumulation of PF4 in atherosclerotic lesions was increased in the acrolein-fed mice. Incubation of endothelial cells with the plasma of acrolein-fed mice augmented transmigration of monocytic cells, which was abolished by anti-PF4 antibody treatment. Conclusions Dietary exposure to acrolein exacerbates atherosclerosis in apoE-null mice. Consumption of foods and beverages rich in unsaturated aldehydes such as acrolein may be a contributing factor to the progression of atherosclerotic lesions. PMID:21371710

  4. Thrombospondin-1 null mice are resistant to hypoxia-induced pulmonary hypertension

    PubMed Central

    2010-01-01

    Background and objective Chronic hypoxia induces pulmonary hypertension in mice. Smooth muscle cell hyperplasia and medial thickening characterize the vasculature of these animals. Thrombospondin-1 null (TSP-1-/-) mice spontaneously develop pulmonary smooth muscle cell hyperplasia and medial thickening. In addition, TSP-1 produced by the pulmonary endothelium inhibits pulmonary artery smooth muscle cell growth. Based on these observations we sought to describe the pulmonary vascular changes in TSP-1-/- mice exposed to chronic hypoxia. Methods We exposed TSP-1-/- and wild type (WT) mice to a fraction of inspired oxygen (FiO2) of 0.1 for up to six weeks. Pulmonary vascular remodeling was evaluated using tissue morphometrics. Additionally, right ventricle systolic pressures (RVSP) and right ventricular hypertrophy by right ventricle/left ventricle + septum ratios (RV/LV+S) were measured to evaluate pulmonary hypertensive changes. Finally, acute pulmonary vasoconstriction response in both TSP-1-/- and WT mice was evaluated by acute hypoxia and U-46619 (a prostaglandin F2 analog) response. Results In hypoxia, TSP-1-/- mice had significantly lower RVSP, RV/LV+S ratios and less pulmonary vascular remodeling when compared to WT mice. TSP-1-/- mice also had significantly lower RVSP in response to acute pulmonary vasoconstriction challenges than their WT counterparts. Conclusion TSP-1-/- mice had diminished pulmonary vasoconstriction response and were less responsive to hypoxia-induced pulmonary hypertension than their wild type counterparts. This observation suggests that TSP-1 could play an active role in the pathogenesis of pulmonary hypertension associated with hypoxia. PMID:20441584

  5. Altered Ca2+ homeostasis in the skeletal muscle of DJ – 1 null mice

    PubMed Central

    Shtifman, Alexander; Zhong, Nan; Lopez, Jose R.; Shen, Jie; Xu, Jin

    2009-01-01

    Loss-of-function mutations in DJ – 1 are associated with early-onset of Parkinson’s disease. Although DJ – 1 is ubiquitously expressed, the functional pathways affected by it remain unresolved. Here we demonstrate an involvement of DJ – 1 in the regulation of Ca2+ homeostasis in mouse skeletal muscle. Using enzymatically dissociated flexor digitorum brevis muscle fibers from wild-type (wt) and DJ – 1 null mice, we examined the effects of DJ – 1 protein on resting, cytoplasmic [Ca2+] ([Ca2+]i) and depolarization-evoked Ca2+ release in the mouse skeletal muscle. The loss of DJ – 1 resulted in a more than two-fold increase in resting [Ca2+]i. While there was no alteration in the resting membrane potential, there was a significant decrease in depolarization-evoked Ca2+ release from the sarcoplasmic reticulum in the DJ – 1 null muscle cells. Consistent with the role of DJ – 1 in oxidative stress regulation and mitochondrial functional maintenance, treatments of DJ – 1 null muscle cells with resveratrol, a mitochondrial activator, or glutathione, a potent antioxidant, reversed the effects of the loss of DJ – 1 on Ca2+ homeostasis. These results provide evidence of DJ – 1’s association with Ca2+ regulatory pathways in mouse skeletal muscle, and suggest the potential benefit of resveratrol to functionally compensate for the loss of DJ – 1. PMID:19683835

  6. Mutations of GJB2 Encoding Connexin 26 Contribute to Nonsyndromic Moderate and Severe Hearing Loss in Pakistan

    PubMed Central

    Salman, Midhat; Bashir, Rasheeda; Imtiaz, Ayesha; Maqsood, Azra; Mujtaba, Ghulam; Iqbal, Muddassar; Naz, Sadaf

    2015-01-01

    Mutations of GJB2 which encodes connexin 26, contribute to 6–7% of profound deafness in Pakistan. We investigated the involvement of GJB2 mutations in a cohort of 84 pedigrees and 86 sporadic individuals with moderate or severe hearing loss. Individuals in eight consanguineous families and four sporadic cases (9.52% and 4.65%, respectively) were homozygous or compound heterozygous for p.W24X or p. W77X mutations in GJB2. These two variants are also among the most common mutations known to cause profound deafness in South Asia. The association of identical mutations with both profound and less severe phenotype of hearing loss suggests that alleles of other genes modify the phenotype due to these GJB2 nonsense mutations. Our study demonstrates that GJB2 mutations are an important contributor to aetiology of moderate to severe hearing loss in Pakistan. PMID:25636251

  7. A novel C202F mutation in the connexin26 gene (GJB2) associated with autosomal dominant isolated hearing loss.

    PubMed

    Morlé, L; Bozon, M; Alloisio, N; Latour, P; Vandenberghe, A; Plauchu, H; Collet, L; Edery, P; Godet, J; Lina-Granade, G

    2000-05-01

    Mutations in the GJB2 gene encoding connexin26 (CX26) account for up to 50% of cases of autosomal recessive hearing loss. In contrast, only one GJB2 mutation has been reported to date in an autosomal dominant form of isolated prelingual hearing loss. We report here a novel heterozygous 605G-->T mutation in GJB2 in all affected members of a large family with late childhood onset of autosomal dominant isolated hearing loss. The resulting C202F substitution, which lies in the fourth (M4) transmembrane domain of CX26, may impair connexin oligomerisation. Finally, our study suggests that GJB2 should be screened for heterozygous mutations in patients with autosomal dominant isolated hearing impairment, whatever the severity of the disease. PMID:10807696

  8. Gap-junctional channel and hemichannel activity of two recently identified connexin 26 mutants associated with deafness.

    PubMed

    Dalamon, Viviana; Fiori, Mariana C; Figueroa, Vania A; Oliva, Carolina A; Del Rio, Rodrigo; Gonzalez, Wendy; Canan, Jonathan; Elgoyhen, Ana B; Altenberg, Guillermo A; Retamal, Mauricio A

    2016-05-01

    Gap-junction channels (GJCs) are formed by head-to-head association of two hemichannels (HCs, connexin hexamers). HCs and GJCs are permeable to ions and hydrophilic molecules of up to Mr ~1 kDa. Hearing impairment of genetic origin is common, and mutations of connexin 26 (Cx26) are its major cause. We recently identified two novel Cx26 mutations in hearing-impaired subjects, L10P and G109V. L10P forms functional GJCs with slightly altered voltage dependence and HCs with decrease ATP/cationic dye selectivity. G109V does not form functional GJCs, but forms functional HCs with enhanced extracellular Ca(2+) sensitivity and subtle alterations in voltage dependence and ATP/cationic dye selectivity. Deafness associated with G109V could result from decreased GJCs activity, whereas deafness associated to L10P may have a more complex mechanism that involves changes in HC permeability. PMID:26769242

  9. Cutaneous metallothionein induction by ultraviolet B irradiation in interleukin-6 null mice.

    PubMed

    Nishimura, N; Reeve, V E; Nishimura, H; Satoh, M; Tohyama, C

    2000-02-01

    The mediators of cutaneous metallothionein induction by ultraviolet radiation have not been defined. In this study we sought to identify cytokines that might be involved. We examined the role of interleukin-6, using the IL-6 null (IL-6-/-) mouse, which has been observed to be highly sensitive to ultraviolet radiation damage. Whereas cutaneous metallothionein concentration, measured by radioimmunoassay, began to rise in wild-type (IL-6+/+) mice by 12 h after ultraviolet irradiation, there was a significant delay in the IL-6-/- mice until 48 h after UV irradiation. Immunohistologically, metallothionein appeared in IL-6+/+ mice at 24 h in dermal fibroblasts, and then by 48 h in epidermal basal keratinocytes, with intensity increasing until 72 h, and was coincident with proliferating cell nuclear antigen-positive staining. Corresponding metallothionein expression in IL-6-/- mouse skin was significantly delayed. Serum interleukin-6 was elevated in IL-6+/+ mice following ultraviolet irradiation, with peak concentration at 4 h, but no increase in serum interleukin-1beta was found in either IL-6+/+ or IL-6-/- mice. Interestingly, tumor necrosis factor alpha concentration in serum was elevated at 12 h postirradiation in IL-6+/+ mice, but there was an earlier (at 4 and 8 h) time-dependent increase in tumor necrosis factor alpha in serum of the IL-6-/- mice. Skin zinc and copper concentrations were not altered by ultraviolet irradiation in either IL-6+/+ or IL-6-/- mice. The results suggest that interleukin-6 may be a very early mediator of cutaneous metallothionein induction by ultraviolet radiation, but that this role is possibly assumed by alternative cytokines like tumor necrosis factor alpha when interleukin-6 is deficient. PMID:10651996

  10. Maturation stage enamel malformations in Amtn and Klk4 null mice.

    PubMed

    Núñez, Stephanie M; Chun, Yong-Hee P; Ganss, Bernhard; Hu, Yuanyuan; Richardson, Amelia S; Schmitz, James E; Fajardo, Roberto; Yang, Jie; Hu, Jan C-C; Simmer, James P

    2016-01-01

    Amelotin (AMTN) and kallikrein-4 (KLK4) are secreted proteins specialized for enamel biomineralization. We characterized enamel from wild-type, Amtn(-/-), Klk4(-/-), Amtn(+/-)Klk4(+/-) and Amtn(-/-)Klk4(-/-) mice to gain insights into AMTN and KLK4 functions during amelogenesis. All of the null mice were healthy and fertile. The mandibular incisors in Amtn(-/-), Klk4(-/-) and Amtn(-/-)Klk4(-/-) mice were chalky-white and chipped. No abnormalities except in enamel were observed, and no significant differences were detected in enamel thickness or volume, or in rod decussation. Micro-computed tomography (μCT) maximum intensity projections localized the onset of enamel maturation in wild-type incisors distal to the first molar, but mesial to this position in Amtn(-/-), Klk4(-/-) and Amtn(-/-)Klk4(-/-) mice, demonstrating a delay in enamel maturation in Amtn(-/-) incisors. Micro-CT detected significantly reduced enamel mineral density (2.5 and 2.4gHA/cm(3)) in the Klk4(-/-) and Amtn(-/-)Klk4(-/-) mice respectively, compared with wild-type enamel (3.1gHA/cm(3)). Backscatter scanning electron microscopy showed that mineral density progressively diminished with enamel depth in the Klk4(-/-) and Amtn(-/-)Klk4(-/-) mice. The Knoop hardness of the Amtn(-/-) outer enamel was significantly reduced relative to the wild-type and was not as hard as the middle or inner enamel. Klk4(-/-) enamel hardness was significantly reduced at all levels, but the outer enamel was significantly harder than the inner and middle enamel. Thus the hardness patterns of the Amtn(-/-) and Klk4(-/-) mice were distinctly different, while the Amtn(-/-)Klk4(-/-) outer enamel was not as hard as in the Amtn(-/-) and Klk4(-/-) mice. We conclude that AMTN and KLK4 function independently, but are both necessary for proper enamel maturation. PMID:26620968

  11. Modulation of ozone-sensitive genes in alpha-tocopherol transfer protein null mice

    PubMed Central

    Vasu, Vihas T.; Oommen, Saji; Lim, Yunsook; Valacchi, Giuseppe; Hobson, Brad; Eiserich, Jason P.; Leonard, Scott W.; Traber, Maret G.; Cross, Carroll E.; Gohil, Kishorchandra

    2009-01-01

    Alpha-tocopherol transfer protein (ATTP) null mice (ATTP−/−) have a systemic alpha-tocopherol (AT) deficiency, with their lung AT levels being < 10% of those in AT-replete ATTP+/+ mice when fed a standard rodent chow diet. ATTP+/+ and ATTP−/− mice (4 wk old male mice, n = 16 per group) were fed a standard diet (35 IU AT/kg diet) for 8–12 wk, exposed 6 h/day for 3 days to either to O3 (0.5 ppm) or filtered air, then sacrificed. No significant differences in plasma or lung AT concentrations were observed in response to this level of O3 exposure. Lung genomic responses of the lungs to O3 were determined using Affymetrix 430A 2.0 arrays containing over 22,600 probe sets representing 14,000 well-characterized mouse genes. As compared with filtered air exposure, O3 exposure resulted in 99 genes being differentially expressed in ATTP−/− mice, as compared to 52 differentially expressed genes in ATTP+/+ mice. The data revealed an O3-induced upregulation of genes related to cell proliferation/DNA repair and inflammatory-immune responses in both ATTP+/+ and ATTP−/− mice, with the expression of 22 genes being common to both, whereas 30 and 77 genes were unique to ATTP+/+ and ATTP−/− mice, respectively. The expressions of O3 sensitive genes—Timp1, Areg, Birc5 and Tnc—were seen to be further modulated by AT status. The present study reveals AT modulation of adaptive response of lung genome to O3 exposure. PMID:19555225

  12. Increased Sensitivity of Glutathione S-Transferase P-Null Mice to Cyclophosphamide-Induced Urinary Bladder Toxicity

    PubMed Central

    Haberzettl, Petra; Lesgards, Jean-Francois; Prough, Russell A.; Srivastava, Sanjay; Bhatnagar, Aruni

    2009-01-01

    Hemorrhagic cystitis and diffuse inflammation of the bladder, common side effects of cyclophosphamide (CY) treatment, have been linked to the generation of acrolein derived from CY metabolism. Metabolic removal of acrolein involves multiple pathways, which include reduction, oxidation, and conjugation with glutathione. Herein, we tested the hypothesis that glutathione S-transferase P (GSTP), the GST isoform that displays high catalytic efficiency with acrolein, protects against CY-induced urotoxicity by detoxifying acrolein. Treatment of wild-type (WT) and mGstP1/P2 null (GSTP-null) mice with CY caused hemorrhagic cystitis, edema, albumin extravasation, and sloughing of bladder epithelium; however, CY-induced bladder ulcerations of the lamina propria were more numerous and more severe in GSTP-null mice. CY treatment also led to greater accumulation of myeloperoxidase-positive cells and specific protein-acrolein adducts in the bladder of GSTP-null than WT mice. There was no difference in hepatic microsomal production of acrolein from CY or urinary hydroxypropyl mercapturic acid output between WT and GSTP-null mice, but CY induced greater c-Jun NH2-terminal kinase (JNK) and c-Jun, but not extracellular signal-regulated kinase or p38, activation in GSTP-null than in WT mice. Pretreatment with mesna (2-mercaptoethane sulfonate sodium) abolished CY toxicity and JNK activation in GSTP-null mice. Taken together, these data support the view that GSTP prevents CY-induced bladder toxicity, in part by detoxifying acrolein. Because polymorphisms in human GSTP gene code for protein variants differing significantly in their catalytic efficiency toward acrolein, it is likely that GSTP polymorphisms influence CY urotoxicity. In addition, pretreatment with dietary or nutrient inducers of GSTP may be of use in minimizing bladder injury in patients undergoing CY therapy. PMID:19696094

  13. Altered Arachidonate Distribution in Macrophages from Caveolin-1 Null Mice Leading to Reduced Eicosanoid Synthesis*

    PubMed Central

    Astudillo, Alma M.; Pérez-Chacón, Gema; Meana, Clara; Balgoma, David; Pol, Albert; del Pozo, Miguel A.; Balboa, María A.; Balsinde, Jesús

    2011-01-01

    In this work we have studied the effect of caveolin-1 deficiency on the mechanisms that regulate free arachidonic acid (AA) availability. The results presented here demonstrate that macrophages from caveolin-1-deficient mice exhibit elevated fatty acid incorporation and remodeling and a constitutively increased CoA-independent transacylase activity. Mass spectrometry-based lipidomic analyses reveal stable alterations in the profile of AA distribution among phospholipids, manifested by reduced levels of AA in choline glycerophospholipids but elevated levels in ethanolamine glycerophospholipids and phosphatidylinositol. Furthermore, macrophages from caveolin-1 null mice show decreased AA mobilization and prostaglandin E2 and LTB4 production upon cell stimulation. Collectively, these results provide insight into the role of caveolin-1 in AA homeostasis and suggest an important role for this protein in the eicosanoid biosynthetic response. PMID:21852231

  14. Behavioral disturbances in estrogen-related receptor alpha-null mice.

    PubMed

    Cui, Huxing; Lu, Yuan; Khan, Michael Z; Anderson, Rachel M; McDaniel, Latisha; Wilson, Hannah E; Yin, Terry C; Radley, Jason J; Pieper, Andrew A; Lutter, Michael

    2015-04-21

    Eating disorders, such as anorexia nervosa and bulimia nervosa, are common and severe mental illnesses of unknown etiology. Recently, we identified a rare missense mutation in the transcription factor estrogen-related receptor alpha (ESRRA) that is associated with the development of eating disorders. However, little is known about ESRRA function in the brain. Here, we report that Esrra is expressed in the mouse brain and demonstrate that Esrra levels are regulated by energy reserves. Esrra-null female mice display a reduced operant response to a high-fat diet, compulsivity/behavioral rigidity, and social deficits. Selective Esrra knockdown in the prefrontal and orbitofrontal cortices of adult female mice recapitulates reduced operant response and increased compulsivity, respectively. These results indicate that Esrra deficiency in the mouse brain impairs behavioral responses in multiple functional domains. PMID:25865889

  15. Behavioral Disturbances in Estrogen-Related Receptor alpha-Null Mice

    PubMed Central

    Cui, Huxing; Lu, Yuan; Khan, Michael Z.; Anderson, Rachel M.; McDaniel, Latisha; Wilson, Hannah E.; Yin, Terry C.; Radley, Jason J.; Pieper, Andrew A.; Lutter, Michael

    2015-01-01

    SUMMARY Eating disorders, such as anorexia nervosa and bulimia nervosa, are common and severe mental illnesses of unknown etiology. Recently, we identified a rare missense mutation in the transcription factor estrogen-related receptor alpha (ESRRA) that is associated with the development of eating disorders. However, little is known about ESRRA function in the brain. Here, we report that Esrra is expressed in the mouse brain and demonstrate that Esrra levels are regulated by energy reserves. Esrra-null female mice display a reduced operant response to a high-fat diet, compulsivity/behavioral rigidity, and social deficits. Selective Esrra knockdown in the prefrontal and orbitofrontal cortices of adult female mice recapitulates reduced operant response and increased compulsivity, respectively. These results indicate that Esrra deficiency in the mouse brain impairs behavioral responses in multiple functional domains. PMID:25865889

  16. Neto2-null mice have impaired GABAergic inhibition and are susceptible to seizures.

    PubMed

    Mahadevan, Vivek; Dargaei, Zahra; Ivakine, Evgueni A; Hartmann, Anna-Maria; Ng, David; Chevrier, Jonah; Ormond, Jake; Nothwang, Hans Gerd; McInnes, Roderick R; Woodin, Melanie A

    2015-01-01

    Neto2 is a transmembrane protein that interacts with the neuron-specific K(+)-Cl(-) cotransporter (KCC2) in the central nervous system (CNS). Efficient KCC2 transport is essential for setting the neuronal Cl(-) gradient, which is required for fast GABAergic inhibition. Neto2 is required to maintain the normal abundance of KCC2 in neurons, and increases KCC2 function by binding to the active oligomeric form of this cotransporter. In the present study, we characterized GABAergic inhibition and KCC2-mediated neuronal chloride homeostasis in pyramidal neurons from adult hippocampal slices. Using gramicidin perforated patch clamp recordings we found that the reversal potential for GABA (EGABA) was significantly depolarized. We also observed that surface levels of KCC2 and phosphorylation of KCC2 serine 940 (Ser940) were reduced in Neto2(-/-) neurons compared to wild-type controls. To examine GABAergic inhibition we recorded spontaneous inhibitory postsynaptic currents (sIPSCs) and found that Neto2(-/-) neurons had significant reductions in both their amplitude and frequency. Based on the critical role of Neto2 in regulating GABAergic inhibition we rationalized that Neto2-null mice would be prone to seizure activity. We found that Neto2-null mice demonstrated a decrease in the latency to pentylenetetrazole (PTZ)-induced seizures and an increase in seizure severity. PMID:26441539

  17. Neto2-null mice have impaired GABAergic inhibition and are susceptible to seizures

    PubMed Central

    Mahadevan, Vivek; Dargaei, Zahra; Ivakine, Evgueni A.; Hartmann, Anna-Maria; Ng, David; Chevrier, Jonah; Ormond, Jake; Nothwang, Hans Gerd; McInnes, Roderick R.; Woodin, Melanie A.

    2015-01-01

    Neto2 is a transmembrane protein that interacts with the neuron-specific K+-Cl− cotransporter (KCC2) in the central nervous system (CNS). Efficient KCC2 transport is essential for setting the neuronal Cl− gradient, which is required for fast GABAergic inhibition. Neto2 is required to maintain the normal abundance of KCC2 in neurons, and increases KCC2 function by binding to the active oligomeric form of this cotransporter. In the present study, we characterized GABAergic inhibition and KCC2-mediated neuronal chloride homeostasis in pyramidal neurons from adult hippocampal slices. Using gramicidin perforated patch clamp recordings we found that the reversal potential for GABA (EGABA) was significantly depolarized. We also observed that surface levels of KCC2 and phosphorylation of KCC2 serine 940 (Ser940) were reduced in Neto2−/− neurons compared to wild-type controls. To examine GABAergic inhibition we recorded spontaneous inhibitory postsynaptic currents (sIPSCs) and found that Neto2−/− neurons had significant reductions in both their amplitude and frequency. Based on the critical role of Neto2 in regulating GABAergic inhibition we rationalized that Neto2-null mice would be prone to seizure activity. We found that Neto2-null mice demonstrated a decrease in the latency to pentylenetetrazole (PTZ)-induced seizures and an increase in seizure severity. PMID:26441539

  18. Autism phenotypes in ZnT3 null mice: Involvement of zinc dyshomeostasis, MMP-9 activation and BDNF upregulation

    PubMed Central

    Yoo, Min Heui; Kim, Tae-Youn; Yoon, Young Hee; Koh, Jae-Young

    2016-01-01

    To investigate the role of synaptic zinc in the ASD pathogenesis, we examined zinc transporter 3 (ZnT3) null mice. At 4–5 weeks of age, male but not female ZnT3 null mice exhibited autistic-like behaviors. Cortical volume and neurite density were significantly greater in male ZnT3 null mice than in WT mice. In male ZnT3 null mice, consistent with enhanced neurotrophic stimuli, the level of BDNF as well as activity of MMP-9 was increased. Consistent with known roles for MMPs in BDNF upregulation, 2.5-week treatment with minocycline, an MMP inhibitor, significantly attenuated BDNF levels as well as megalencephaly and autistic-like behaviors. Although the ZnT3 null state removed synaptic zinc, it rather increased free zinc in the cytosol of brain cells, which appeared to increase MMP-9 activity and BDNF levels. The present results suggest that zinc dyshomeostasis during the critical period of brain development may be a possible contributing mechanism for ASD. PMID:27352957

  19. Posttranslational Modifications in Type I Collagen from Different Tissues Extracted from Wild Type and Prolyl 3-Hydroxylase 1 Null Mice*

    PubMed Central

    Pokidysheva, Elena; Zientek, Keith D.; Ishikawa, Yoshihiro; Mizuno, Kazunori; Vranka, Janice A.; Montgomery, Nathan T.; Keene, Douglas R.; Kawaguchi, Tatsuya; Okuyama, Kenji; Bächinger, Hans Peter

    2013-01-01

    Type I collagen extracted from tendon, skin, and bone of wild type and prolyl 3-hydroxylase 1 (P3H1) null mice shows distinct patterns of 3-hydroxylation and glycosylation of hydroxylysine residues. The A1 site (Pro-986) in the α1-chain of type I collagen is almost completely 3-hydroxylated in every tissue of the wild type mice. In contrast, no 3-hydroxylation of this proline residue was found in P3H1 null mice. Partial 3-hydroxylation of the A3 site (Pro-707) was present in tendon and bone, but absent in skin in both α-chains of the wild type animals. Type I collagen extracted from bone of P3H1 null mice shows a large reduction in 3-hydroxylation of the A3 site in both α-chains, whereas type I collagen extracted from tendon of P3H1 null mice shows little difference as compared with wild type. These results demonstrate that the A1 site in type I collagen is exclusively 3-hydroxylated by P3H1, and presumably, this enzyme is required for the 3-hydroxylation of the A3 site of both α-chains in bone but not in tendon. The increase in glycosylation of hydroxylysine in P3H1 null mice in bone was found to be due to an increased occupancy of normally glycosylated sites. Despite the severe disorganization of collagen fibrils in adult tissues, the D-period of the fibrils is unchanged. Tendon fibrils of newborn P3H1 null mice are well organized with only a slight increase in diameter. The absence of 3-hydroxyproline and/or the increased glycosylation of hydroxylysine in type I collagen disturbs the lateral growth of the fibrils. PMID:23861401

  20. Carrageenan-Induced Colonic Inflammation Is Reduced in Bcl10 Null Mice and Increased in IL-10-Deficient Mice

    PubMed Central

    Bhattacharyya, Sumit; Xue, Liquan; Devkota, Suzanne; Chang, Eugene; Morris, Stephan; Tobacman, Joanne K.

    2013-01-01

    The common food additive carrageenan is a known activator of inflammation in mammalian tissues and stimulates both the canonical and noncanonical pathways of NF-κB activation. Exposure to low concentrations of carrageenan (10 μg/mL in the water supply) has produced glucose intolerance, insulin resistance, and impaired insulin signaling in C57BL/6 mice. B-cell leukemia/lymphoma 10 (Bcl10) is a mediator of inflammatory signals from Toll-like receptor (TLR) 4 in myeloid and epithelial cells. Since the TLR4 signaling pathway is activated in diabetes and by carrageenan, we addressed systemic and intestinal inflammatory responses following carrageenan exposure in Bcl10 wild type, heterozygous, and null mice. Fecal calprotectin and circulating keratinocyte chemokine (KC), nuclear RelA and RelB, phospho(Thr559)-NF-κB-inducing kinase (NIK), and phospho(Ser36)-IκBα in the colonic epithelial cells were significantly less (P < 0.001) in the carrageenan-treated Bcl10 null mice than in controls. IL-10-deficient mice exposed to carrageenan in a germ-free environment showed an increase in activation of the canonical pathway of NF-κB (RelA) activation, but without increase in RelB or phospho-Bcl10, and exogenous IL-10 inhibited only the canonical pathway of NF-κB activation in cultured colonic cells. These findings demonstrate a Bcl10 requirement for maximum development of carrageenan-induced inflammation and lack of complete suppression by IL-10 of carrageenan-induced inflammation. PMID:23766559

  1. Cardiac hypertrophy in anion exchanger 1-null mutant mice with severe hemolytic anemia.

    PubMed

    Alvarez, Bernardo V; Kieller, Dawn M; Quon, Anita L; Robertson, Murray; Casey, Joseph R

    2007-03-01

    Anion exchanger 1 (AE1; SLC4A1), the plasma membrane Cl(-)/HCO(3)(-) exchanger of erythrocytes, is also expressed in heart. The aim of this study was to assess the role of AE1 in heart function through study of AE1-null (AE1(-/-)) mice, which manifest severe hemolytic anemia resulting from erythrocyte fragility. Heart weight-to-body weight ratios were significantly higher in the AE1(-/-) mice than in wild-type (AE1(+/+)) littermates at both 1-3 days postnatal (3.01 +/- 0.38 vs. 1.45 +/- 0.04) and at 7 days postnatal (9.45 +/- 0.53 vs. 4.13 +/- 0.41), indicating that loss of AE1 led to cardiac hypertrophy. Heterozygous (AE1(+/-)) mice had no signs of cardiac hypertrophy. Morphology of the adult AE1(-/-) mutant heart revealed an increased left ventricular mass, accompanied by increased collagen deposition and fibrosis. M-mode echocardiography revealed dysfunction of the AE1(-/-) hearts, including dilated left ventricle end diastole and systole and expanded left ventricular mass compared with AE1(+/+) hearts. Expression of intracellular pH-regulatory mechanisms in the hypertrophic myocardium of neonate AE1(-/-) mutant mice was indistinguishable from AE1(+/-) and AE1(+/+) mice, as assessed by quantitative real-time RT-PCR. Confocal immunofluorescence revealed that, in normal mouse myocardium, AE1 is sarcolemmal, whereas AE3 and slc26a6 are found both at the sarcolemma and in internal membranes (T tubules and sarcoplasmic reticulum). These results indicate that AE1(-/-) mice, which suffer from severe hemolytic anemia and spherocytosis, display cardiac hypertrophy and impaired cardiac function, reminiscent of findings in patients with hereditary abnormalities of red blood cells. No essential role for AE1 in heart function was found. PMID:17056673

  2. Vitamin D and Human Health: Lessons from Vitamin D Receptor Null Mice

    PubMed Central

    Bouillon, Roger; Carmeliet, Geert; Verlinden, Lieve; van Etten, Evelyne; Verstuyf, Annemieke; Luderer, Hilary F.; Lieben, Liesbet; Mathieu, Chantal; Demay, Marie

    2008-01-01

    The vitamin D endocrine system is essential for calcium and bone homeostasis. The precise mode of action and the full spectrum of activities of the vitamin D hormone, 1,25-dihydroxyvitamin D [1,25-(OH)2D], can now be better evaluated by critical analysis of mice with engineered deletion of the vitamin D receptor (VDR). Absence of a functional VDR or the key activating enzyme, 25-OHD-1α-hydroxylase (CYP27B1), in mice creates a bone and growth plate phenotype that mimics humans with the same congenital disease or severe vitamin D deficiency. The intestine is the key target for the VDR because high calcium intake, or selective VDR rescue in the intestine, restores a normal bone and growth plate phenotype. The VDR is nearly ubiquitously expressed, and almost all cells respond to 1,25-(OH)2D exposure; about 3% of the mouse or human genome is regulated, directly and/or indirectly, by the vitamin D endocrine system, suggesting a more widespread function. VDR-deficient mice, but not vitamin D- or 1α-hydroxylase-deficient mice, and man develop total alopecia, indicating that the function of the VDR and its ligand is not fully overlapping. The immune system of VDR- or vitamin D-deficient mice is grossly normal but shows increased sensitivity to autoimmune diseases such as inflammatory bowel disease or type 1 diabetes after exposure to predisposing factors. VDR-deficient mice do not have a spontaneous increase in cancer but are more prone to oncogene- or chemocarcinogen-induced tumors. They also develop high renin hypertension, cardiac hypertrophy, and increased thrombogenicity. Vitamin D deficiency in humans is associated with increased prevalence of diseases, as predicted by the VDR null phenotype. Prospective vitamin D supplementation studies with multiple noncalcemic endpoints are needed to define the benefits of an optimal vitamin D status. PMID:18694980

  3. Transgenic expression of Dspp partially rescued the long bone defects of Dmp1-null mice.

    PubMed

    Jani, Priyam H; Gibson, Monica P; Liu, Chao; Zhang, Hua; Wang, Xiaofang; Lu, Yongbo; Qin, Chunlin

    2016-01-01

    Dentin matrix protein 1 (DMP1) and dentin sialophosphoprotein (DSPP) belong to the Small Integrin-Binding Ligand N-linked Glycoprotein (SIBLING) family. In addition to the features common to all SIBLING members, DMP1 and DSPP share several unique similarities in chemical structure, proteolytic activation and tissue localization. Mutations in, or deletion of DMP1, cause autosomal recessive hypophosphatemic rickets along with dental defects; DSPP mutations or its ablation are associated with dentinogenesis imperfecta. While the roles and functional mechanisms of DMP1 in osteogenesis have been extensively studied, those of DSPP in long bones have been studied only to a limited extent. Previous studies by our group revealed that transgenic expression of Dspp completely rescued the dentin defects of Dmp1-null (Dmp1(-/-)) mice. In this investigation, we assessed the effects of transgenic Dspp on osteogenesis by analyzing the formation and mineralization of the long bones in Dmp1(-/-) mice that expresses a transgene encoding full-length DSPP driven by a 3.6-kb rat Col1a1 promoter (referred as "Dmp1(-/-);Dspp-Tg mice"). We characterized the long bones of the Dmp1(-/-);Dspp-Tg mice at different ages and compared them with those from Dmp1(-/-) and Dmp1(+/-) (normal control) mice. Our analyses showed that the long bones of Dmp1(-/-);Dspp-Tg mice had a significant increase in cortical bone thickness, bone volume and mineral density along with a remarkable restoration of trabecular thickness compared to those of the Dmp1(-/-) mice. The long bones of Dmp1(-/-);Dspp-Tg mice underwent a dramatic reduction in the amount of osteoid, significant improvement of the collagen fibrillar network, and better organization of the lacunocanalicular system, compared to the Dmp1(-/-) mice. The elevated levels of biglycan, bone sialoprotein and osteopontin in Dmp1(-/-) mice were also noticeably corrected by the transgenic expression of Dspp. These findings suggest that DSPP and DMP1 may function

  4. Reduced wheel running and blunted effects of voluntary exercise in LPA1-null mice: The importance of assessing the amount of running in transgenic mice studies

    PubMed Central

    Castilla-Ortega, Estela; Rosell-Valle, Cristina; Blanco, Eduardo; Pedraza, Carmen; Chun, Jerold; de Fonseca, Fernando Rodríguez; Estivill-Torrús, Guillermo; Santín, Luis J.

    2014-01-01

    This work was aimed to assess whether voluntary exercise rescued behavioral and hippocampal alterations in mice lacking the lysophosphatidic acid LPA1 receptor (LPA1-null mice), studying the potential relationship between the amount of exercise performed and its effects. Normal and LPA1-null mice underwent 23 days of free wheel running and were tested for open-field behavior and adult hippocampal neurogenesis (cell proliferation, immature neurons, cell survival). Running decreased anxiety-like behavior in both genotypes but increased exploration only in the normal mice. While running affected all neurogenesis-related measures in normal mice (especially in the suprapyramidal blade of the dentate gyrus), only a moderate increase in cell survival was found in the mutants. Importantly, the LPA1-nulls showed notably reduced running. Analysis suggested that defective running in the LPA1-null mice could contribute to explain the scarce benefit of the voluntary exercise treatment. On the other hand, a literature review revealed that voluntary exercise is frequently used to modulate behavior and the hippocampus in transgenic mice, but half of the studies did not assess the quantity of running, overlooking any potential running impairments. This study adds evidence to the relevance of the quantity of exercise performed, emphasizing the importance of its assessment in transgenic mice research. PMID:24055600

  5. Disturbance of cardiac gene expression and cardiomyocyte structure predisposes Mecp2-null mice to arrhythmias

    PubMed Central

    Hara, Munetsugu; Takahashi, Tomoyuki; Mitsumasu, Chiaki; Igata, Sachiyo; Takano, Makoto; Minami, Tomoko; Yasukawa, Hideo; Okayama, Satoko; Nakamura, Keiichiro; Okabe, Yasunori; Tanaka, Eiichiro; Takemura, Genzou; Kosai, Ken-ichiro; Yamashita, Yushiro; Matsuishi, Toyojiro

    2015-01-01

    Methyl-CpG-binding protein 2 (MeCP2) is an epigenetic regulator of gene expression that is essential for normal brain development. Mutations in MeCP2 lead to disrupted neuronal function and can cause Rett syndrome (RTT), a neurodevelopmental disorder. Previous studies reported cardiac dysfunction, including arrhythmias in both RTT patients and animal models of RTT. In addition, recent studies indicate that MeCP2 may be involved in cardiac development and dysfunction, but its role in the developing and adult heart remains unknown. In this study, we found that Mecp2-null ESCs could differentiate into cardiomyocytes, but the development and further differentiation of cardiovascular progenitors were significantly affected in MeCP2 deficiency. In addition, we revealed that loss of MeCP2 led to dysregulation of endogenous cardiac genes and myocardial structural alterations, although Mecp2-null mice did not exhibit obvious cardiac functional abnormalities. Furthermore, we detected methylation of the CpG islands in the Tbx5 locus, and showed that MeCP2 could target these sequences. Taken together, these results suggest that MeCP2 is an important regulator of the gene-expression program responsible for maintaining normal cardiac development and cardiomyocyte structure. PMID:26073556

  6. Disturbance of cardiac gene expression and cardiomyocyte structure predisposes Mecp2-null mice to arrhythmias.

    PubMed

    Hara, Munetsugu; Takahashi, Tomoyuki; Mitsumasu, Chiaki; Igata, Sachiyo; Takano, Makoto; Minami, Tomoko; Yasukawa, Hideo; Okayama, Satoko; Nakamura, Keiichiro; Okabe, Yasunori; Tanaka, Eiichiro; Takemura, Genzou; Kosai, Ken-ichiro; Yamashita, Yushiro; Matsuishi, Toyojiro

    2015-01-01

    Methyl-CpG-binding protein 2 (MeCP2) is an epigenetic regulator of gene expression that is essential for normal brain development. Mutations in MeCP2 lead to disrupted neuronal function and can cause Rett syndrome (RTT), a neurodevelopmental disorder. Previous studies reported cardiac dysfunction, including arrhythmias in both RTT patients and animal models of RTT. In addition, recent studies indicate that MeCP2 may be involved in cardiac development and dysfunction, but its role in the developing and adult heart remains unknown. In this study, we found that Mecp2-null ESCs could differentiate into cardiomyocytes, but the development and further differentiation of cardiovascular progenitors were significantly affected in MeCP2 deficiency. In addition, we revealed that loss of MeCP2 led to dysregulation of endogenous cardiac genes and myocardial structural alterations, although Mecp2-null mice did not exhibit obvious cardiac functional abnormalities. Furthermore, we detected methylation of the CpG islands in the Tbx5 locus, and showed that MeCP2 could target these sequences. Taken together, these results suggest that MeCP2 is an important regulator of the gene-expression program responsible for maintaining normal cardiac development and cardiomyocyte structure. PMID:26073556

  7. Reactivation of autophagy by spermidine ameliorates the myopathic defects of collagen VI-null mice

    PubMed Central

    Chrisam, Martina; Pirozzi, Marinella; Castagnaro, Silvia; Blaauw, Bert; Polishchuck, Roman; Cecconi, Francesco; Grumati, Paolo; Bonaldo, Paolo

    2015-01-01

    Autophagy is a self-degradative process responsible for the clearance of damaged or unnecessary cellular components. We have previously found that persistence of dysfunctional organelles due to autophagy failure is a key event in the pathogenesis of COL6/collagen VI-related myopathies, and have demonstrated that reactivation of a proper autophagic flux rescues the muscle defects of Col6a1-null (col6a1−/−) mice. Here we show that treatment with spermidine, a naturally occurring nontoxic autophagy inducer, is beneficial for col6a1−/− mice. Systemic administration of spermidine in col6a1−/− mice reactivated autophagy in a dose-dependent manner, leading to a concurrent amelioration of the histological and ultrastructural muscle defects. The beneficial effects of spermidine, together with its being easy to administer and the lack of overt side effects, open the field for the design of novel nutraceutical strategies for the treatment of muscle diseases characterized by autophagy impairment. PMID:26565691

  8. Phenotypic Characterization of Mice Heterozygous for a Null Mutation of Glutamate Carboxypeptidase II

    PubMed Central

    Han, Liqun; Picker, Jonathan D.; Schaevitz, Laura R.; Tsai, Guochuan; Feng, Jiamin; Jiang, Zhichun; Chu, Hillary C.; Basu, Alo C.; Berger-Sweeney, Joanne; Coyle, Joseph T.

    2009-01-01

    Glutamate is the major excitatory neurotransmitter in the mammalian central nervous system. Disturbed glutamate signaling resulting in hypofunction of NMDA receptors has been implicated in the pathophysiology of schizophrenia. Glutamate Carboxypeptidase II (GCP II) hydrolyzes N-acetyl-alpha L-aspartyl-L-glutamate (NAAG) into glutamate and N-acetyl-aspartate (NAA). NAAG is a neuropeptide that is an NMDA receptor antagonist as well as an agonist for the metabotropic glutamate receptor-3 (mGluR3), which inhibits glutamate release. The aggregate effect of NAAG is thus to attenuate NMDA receptor activation. To manipulate the expression of GCP II, loxP sites were inserted flanking exon 1 and 2, which were excised by crossing with a Cre-expressing mouse. The mice heterozygous for this deletion showed a 50% reduction in the expression level of protein and functional activity of GCP II in brain samples. Heterozygous mutant crosses did not yield any homozygous null animals at birth or as embryos (N >200 live births and fetuses). These data are consistent with the previous report that GCP II homozygous mutant mice generated by removing exons 9 and 10 of GCP II gene were embryonically lethal and confirm our hypothesis that GCP II plays an essential role early in embryonic development. Heterozygous mice, however, developed normally to adulthood and exhibited increased locomotor activity, reduced social interaction, and a subtle cognitive deficit in working memory. PMID:19347959

  9. Phenotypic characterization of mice heterozygous for a null mutation of glutamate carboxypeptidase II.

    PubMed

    Han, Liqun; Picker, Jonathan D; Schaevitz, Laura R; Tsai, Guochuan; Feng, Jiamin; Jiang, Zhichun; Chu, Hillary C; Basu, Alo C; Berger-Sweeney, Joanne; Coyle, Joseph T

    2009-08-01

    Glutamate is the major excitatory neurotransmitter in the mammalian central nervous system. Disturbed glutamate signaling resulting in hypofunction of N-methyl-D-aspartate receptors (NMDAR) has been implicated in the pathophysiology of schizophrenia. Glutamate Carboxypeptidase II (GCP II) hydrolyzes N-acetyl-alpha L-aspartyl-L-glutamate (NAAG) into glutamate and N-acetyl-aspartate. NAAG is a neuropeptide that is an NMDAR antagonist as well as an agonist for the metabotropic glutamate receptor-3 (mGluR3), which inhibits glutamate release. The aggregate effect of NAAG is thus to attenuate NMDAR activation. To manipulate the expression of GCP II, LoxP sites were inserted flanking exons 1 and 2, which were excised by crossing with a Cre-expressing mouse. The mice heterozygous for this deletion showed a 50% reduction in the expression level of protein and functional activity of GCP II in brain samples. Heterozygous mutant crosses did not yield any homozygous null animals at birth or as embryos (N > 200 live births and fetuses). These data are consistent with the previous report that GCP II homozygous mutant mice generated by removing exons 9 and 10 of GCP II gene were embryonically lethal and confirm our hypothesis that GCP II plays an essential role early in embryonic development. Heterozygous mice, however, developed normally to adulthood and exhibited increased locomotor activity, reduced social interaction, and a subtle cognitive deficit in working memory. PMID:19347959

  10. Myelinogenesis and axonal recognition by oligodendrocytes in brain are uncoupled in Olig1-null mice.

    PubMed

    Xin, Mei; Yue, Tao; Ma, Zhenyi; Wu, Fen-fen; Gow, Alexander; Lu, Q Richard

    2005-02-01

    Myelin-forming oligodendrocytes facilitate saltatory nerve conduction and support neuronal functions in the mammalian CNS. Although the processes of oligodendrogliogenesis and differentiation from neural progenitor cells have come to light in recent years, the molecular mechanisms underlying oligodendrocyte myelinogenesis are poorly defined. Herein, we demonstrate the pivotal role of the basic helix-loop-helix transcription factor, Olig1, in oligodendrocyte myelinogenesis in brain development. Mice lacking a functional Olig1 gene develop severe neurological deficits and die in the third postnatal week. In the brains of these mice, expression of myelin-specific genes is abolished, whereas the formation of oligodendrocyte progenitors is not affected. Furthermore, multilamellar wrapping of myelin membranes around axons does not occur, despite recognition and contact of axons by oligodendrocytes, and Olig1-null mice develop widespread progressive axonal degeneration and gliosis. In contrast, myelin sheaths are formed in the spinal cord, although the extent of myelination is severely reduced. At the molecular level, we find that Olig1 regulates transcription of the major myelin-specific genes, Mbp, Plp1, and Mag, and suppresses expression of a major astrocyte-specific gene, Gfap. Together, our data indicate that Olig1 is a central regulator of oligodendrocyte myelinogenesis in brain and that axonal recognition and myelination by oligodendrocytes are separable processes. PMID:15703389

  11. Improved muscle healing through enhanced regeneration and reduced fibrosis in myostatin-null mice.

    PubMed

    McCroskery, Seumas; Thomas, Mark; Platt, Leanne; Hennebry, Alex; Nishimura, Takanori; McLeay, Lance; Sharma, Mridula; Kambadur, Ravi

    2005-08-01

    Numerous stimulatory growth factors that can influence muscle regeneration are known. Recently, it has been demonstrated that neutralization of muscle growth inhibitory factors, such as myostatin (Mstn; also known as growth differentiation factor 8, Gdf8), also leads to increased muscle regeneration in mdx mice that are known to have cycles of degeneration. However, the precise mechanism by which Mstn regulates muscle regeneration has not yet been fully determined. To investigate the role of Mstn in adult skeletal muscle regeneration, wild-type and myostatin-null (Mstn-/-) mice were injured with notexin. Forty-eight hours after injury, accelerated migration and enhanced accretion of myogenic cells (MyoD1+) and macrophages (Mac-1+) was observed at the site of regeneration in Mstn-/- muscle as compared with wild-type muscle. Inflammatory cell numbers decreased more rapidly in the Mstn-/- muscle, indicating that the whole process of inflammatory cell response is accelerated in Mstn-/- mice. Consistent with this result, the addition of recombinant Mstn reduced the activation of satellite cells (SCs) and chemotactic movements of both myoblasts and macrophages ex vivo. Examination of regenerated muscle (28 days after injury) also revealed that Mstn-/- mice showed increased expression of decorin mRNA, reduced fibrosis and improved healing as compared with wild-type mice. On the basis of these results, we propose that Mstn negatively regulates muscle regeneration not only by controlling SC activation but also by regulating the migration of myoblasts and macrophages to the site of injury. Thus, antagonists of Mstn could potentially be useful as pharmacological agents for the treatment of disorders of overt degeneration and regeneration. PMID:16079293

  12. From Hyperactive Connexin26 Hemichannels to Impairments in Epidermal Calcium Gradient and Permeability Barrier in the Keratitis-Ichthyosis-Deafness Syndrome.

    PubMed

    García, Isaac E; Bosen, Felicitas; Mujica, Paula; Pupo, Amaury; Flores-Muñoz, Carolina; Jara, Oscar; González, Carlos; Willecke, Klaus; Martínez, Agustín D

    2016-03-01

    The keratitis-ichthyosis-deafness (KID) syndrome is characterized by corneal, skin, and hearing abnormalities. KID has been linked to heterozygous dominant missense mutations in the GJB2 and GJB6 genes, encoding connexin26 and 30, respectively. In vitro evidence indicates that KID mutations lead to hyperactive (open) hemichannels, which in some cases is accompanied by abnormal function of gap junction channels. Transgenic mouse models expressing connexin26 KID mutations reproduce human phenotypes and present impaired epidermal calcium homeostasis and abnormal lipid composition of the stratum corneum affecting the water barrier. Here we have compiled relevant data regarding the KID syndrome and propose a mechanism for the epidermal aspects of the disease. PMID:26777423

  13. Decreased virus population diversity in p53-null mice infected with weakly oncogenic Abelson virus.

    PubMed

    Marchlik, Erica; Kalman, Richard; Rosenberg, Naomi

    2005-09-01

    The Abelson murine leukemia virus (Ab-MLV), like other retroviruses that contain v-onc genes, arose following a recombination event between a replicating retrovirus and a cellular oncogene. Although experimentally validated models have been presented to address the mechanism by which oncogene capture occurs, very little is known about the events that influence emerging viruses following the recombination event that incorporates the cellular sequences. One feature that may play a role is the genetic makeup of the host in which the virus arises; a number of host genes, including oncogenes and tumor suppressor genes, have been shown to affect the pathogenesis of many murine leukemia viruses. To examine how a host gene might affect an emerging v-onc gene-containing retrovirus, we studied the weakly oncogenic Ab-MLV-P90A strain, a mutant that generates highly oncogenic variants in vivo, and compared the viral populations in normal mice and mice lacking the p53 tumor suppressor gene. While variants arose in both p53+/+ and p53-/- tumors, the samples from the wild-type animals contained a more diverse virus population. Differences in virus population diversity were not observed when wild-type and null animals were infected with a highly oncogenic wild-type strain of Ab-MLV. These results indicate that p53, and presumably other host genes, affects the selective forces that operate on virus populations in vivo and likely influences the evolution of oncogenic retroviruses such as Ab-MLV. PMID:16140739

  14. Deficiency in acellular cementum and periodontal attachment in bsp null mice.

    PubMed

    Foster, B L; Soenjaya, Y; Nociti, F H; Holm, E; Zerfas, P M; Wimer, H F; Holdsworth, D W; Aubin, J E; Hunter, G K; Goldberg, H A; Somerman, M J

    2013-02-01

    Bone sialoprotein (BSP) is an extracellular matrix protein found in mineralized tissues of the skeleton and dentition. BSP is multifunctional, affecting cell attachment and signaling through an RGD integrin-binding region, and acting as a positive regulator for mineral precipitation by nucleating hydroxyapatite crystals. BSP is present in cementum, the hard tissue covering the tooth root that anchors periodontal ligament (PDL) attachment. To test our hypothesis that BSP plays an important role in cementogenesis, we analyzed tooth development in a Bsp null ((-/-)) mouse model. Developmental analysis by histology, histochemistry, and SEM revealed a significant reduction in acellular cementum formation on Bsp (-/-) mouse molar and incisor roots, and the cementum deposited appeared hypomineralized. Structural defects in cementum-PDL interfaces in Bsp (-/-) mice caused PDL detachment, likely contributing to the high incidence of incisor malocclusion. Loss of BSP caused progressively disorganized PDL and significantly increased epithelial down-growth with aging. Bsp (-/-) mice displayed extensive root and alveolar bone resorption, mediated by increased RANKL and the presence of osteoclasts. Results collected here suggest that BSP plays a non-redundant role in acellular cementum formation, likely involved in initiating mineralization on the root surface. Through its importance to cementum integrity, BSP is essential for periodontal function. PMID:23183644

  15. Cognition and Mood-Related Behaviors in L3mbtl1 Null Mutant Mice

    PubMed Central

    Shen, Erica Y.; Jiang, Yan; Mao, Wenjie; Futai, Kensuke; Hock, Hanno; Akbarian, Schahram

    2015-01-01

    Alterations in histone lysine methylation and epigenetic regulators of gene expression could play a role in the neurobiology and treatment of patients diagnosed with mood spectrum disorder, including depression and anxiety. Mutations and altered expression of various lysine methyltransferases (KMTs) and demethylases (KDMs) have been linked to changes in motivational and emotional behaviors in preclinical model systems. However, it is not known whether regulators operating downstream of histone lysine methylation could affect mood-related behavior. Malignant Brain Tumor (MBT) domain ‘chromatin reader’ proteins bind to methylated histone lysine residues and associate with chromatin remodeling complexes to facilitate or repress gene expression. MBT proteins, including the founding member, L3mbtl1, maintain high levels of expression in neurons of the mature brain. Here, we exposed L3mbtl1 null mutant mice to a wide range of tests exploring cognition and mood-relevant behaviors at baseline and in the context of social isolation, as a stressor to elicit depression-related behavior in susceptible mice. L3mbtl1 loss-of-function was associated with significant decreases in depression and and anxiety in some of the behavioral paradigms. This was not associated with a more generalized neurological dysfunction because cognition and memory remained unaltered in comparison to controls. These findings warrant further investigations on the role of MBT chromatin reader proteins in the context of emotional and affective behaviors. PMID:25849281

  16. Loss of locus coeruleus neurons and reduced startle in parkin null mice

    PubMed Central

    von Coelln, Rainer; Thomas, Bobby; Savitt, Joseph M.; Lim, Kah Leong; Sasaki, Masayuki; Hess, Ellen J.; Dawson, Valina L.; Dawson, Ted M.

    2004-01-01

    Parkinson's disease (PD) is the most common neurodegenerative movement disorder and is characterized pathologically by degeneration of catecholaminergic neurons of the substantia nigra pars compacta and locus coeruleus, among other regions. Autosomal-recessive juvenile Parkinsonism (ARJP) is caused by mutations in the PARK2 gene coding for parkin and constitutes the most common familial form of PD. The majority of ARJP-associated parkin mutations are thought to be loss of function-mutations; however, the pathogenesis of ARJP remains poorly understood. Here, we report the generation of parkin null mice by targeted deletion of parkin exon 7. These mice show a loss of catecholaminergic neurons in the locus coeruleus and an accompanying loss of norepinephrine in discrete regions of the central nervous system. Moreover, there is a dramatic reduction of the norepinephrine-dependent startle response. The nigrostriatal dopaminergic system does not show any impairment. This mouse model will help gain a better understanding of parkin function and the mechanisms underlying parkin-associated PD. PMID:15249681

  17. The pathological effects of connexin 26 variants related to hearing loss by in silico and in vitro analysis.

    PubMed

    Kim, Hui Ram; Oh, Se-Kyung; Lee, Eun-Shil; Choi, Soo-Young; Roh, Seung-Eon; Kim, Sang Jeong; Tsukihara, Tomitake; Lee, Kyu-Yup; Jeon, Chang-Jin; Kim, Un-Kyung

    2016-03-01

    Gap junctions (GJs) are intercellular channels associated with cell-cell communication. Connexin 26 (Cx26) encoded by the GJB2 gene forms GJs of the inner ear, and mutations of GJB2 cause congenital hearing loss that can be syndromic or non-syndromic. It is difficult to predict pathogenic effects using only genetic analysis. Using ionic and biochemical coupling tests, we evaluated the pathogenic effects of Cx26 variants using computational analyses to predict structural abnormalities. For seven out of ten variants, we predicted the variation would result in a loss of GJ function, whereas the others would completely fail to form GJs. Functional studies demonstrated that, although all variants were able to function normally as hetero-oligomeric GJ channels, six variants (p.E47K, p.E47Q, p.H100L, p.H100Y, p.R127L, and p.M195L) did not function normally as homo-oligomeric GJ channels. Interestingly, GJs composed of the Cx26 variant p.R127H were able to function normally, even as homo-oligomeric GJ channels. This study demonstrates the particular location and property of an amino acid are more important mainly than the domain where they belong in the formation and function of GJ, and will provide information that is useful for the accurate diagnosis of hearing loss. PMID:26749107

  18. Abnormal neuronal patterning occurs during early postnatal brain development of Scn1b-null mice and precedes hyperexcitability.

    PubMed

    Brackenbury, William J; Yuan, Yukun; O'Malley, Heather A; Parent, Jack M; Isom, Lori L

    2013-01-15

    Voltage-gated Na(+) channel (VGSC) β1 subunits, encoded by SCN1B, are multifunctional channel modulators and cell adhesion molecules (CAMs). Mutations in SCN1B are associated with the genetic epilepsy with febrile seizures plus (GEFS+) spectrum disorders in humans, and Scn1b-null mice display severe spontaneous seizures and ataxia from postnatal day (P)10. The goal of this study was to determine changes in neuronal pathfinding during early postnatal brain development of Scn1b-null mice to test the hypothesis that these CAM-mediated roles of Scn1b may contribute to the development of hyperexcitability. c-Fos, a protein induced in response to seizure activity, was up-regulated in the Scn1b-null brain at P16 but not at P5. Consistent with this, epileptiform activity was observed in hippocampal and cortical slices prepared from the P16 but not from the P5-P7 Scn1b-null brain. On the basis of these results, we investigated neuronal pathfinding at P5. We observed disrupted fasciculation of parallel fibers in the P5 null cerebellum. Further, P5 null mice showed reduced neuron density in the dentate gyrus granule cell layer, increased proliferation of granule cell precursors in the hilus, and defective axonal extension and misorientation of somata and processes of inhibitory neurons in the dentate gyrus and CA1. Thus, Scn1b is critical for neuronal proliferation, migration, and pathfinding during the critical postnatal period of brain development. We propose that defective neuronal proliferation, migration, and pathfinding in response to Scn1b deletion may contribute to the development of hyperexcitability. PMID:23277545

  19. Taurodontism, variations in tooth number, and misshapened crowns in Wnt10a null mice and human kindreds

    PubMed Central

    Yang, Jie; Wang, Shih-Kai; Choi, Murim; Reid, Bryan M; Hu, Yuanyuan; Lee, Yuan-Ling; Herzog, Curtis R; Kim-Berman, Hera; Lee, Moses; Benke, Paul J; Kent Lloyd, K C; Simmer, James P; Hu, Jan C-C

    2015-01-01

    WNT10A is a signaling molecule involved in tooth development, and WNT10A defects are associated with tooth agenesis. We characterized Wnt10a null mice generated by the knockout mouse project (KOMP) and six families with WNT10A mutations, including a novel p.Arg104Cys defect, in the absence of EDA,EDAR, or EDARADD variations. Wnt10a null mice exhibited supernumerary mandibular fourth molars, and smaller molars with abnormal cusp patterning and root taurodontism. Wnt10a−/− incisors showed distinctive apical–lingual wedge-shaped defects. These findings spurred us to closely examine the dental phenotypes of our WNT10A families. WNT10A heterozygotes exhibited molar root taurodontism and mild tooth agenesis (with incomplete penetrance) in their permanent dentitions. Individuals with two defective WNT10A alleles showed severe tooth agenesis and had fewer cusps on their molars. The misshapened molar crowns and roots were consistent with the Wnt10a null phenotype and were not previously associated with WNT10A defects. The missing teeth contrasted with the presence of supplemental teeth in the Wnt10a null mice and demonstrated mammalian species differences in the roles of Wnt signaling in early tooth development. We conclude that molar crown and root dysmorphologies are caused by WNT10A defects and that the severity of the tooth agenesis correlates with the number of defective WNT10A alleles. PMID:25629078

  20. Mecp2-Null Mice Provide New Neuronal Targets for Rett Syndrome

    PubMed Central

    Urdinguio, Rocio G.; Lopez-Serra, Lidia; Lopez-Nieva, Pilar; Alaminos, Miguel; Diaz-Uriarte, Ramon; Fernandez, Agustin F.; Esteller, Manel

    2008-01-01

    Background Rett syndrome (RTT) is a complex neurological disorder that is one of the most frequent causes of mental retardation in women. A great landmark in research in this field was the discovery of a relationship between the disease and the presence of mutations in the gene that codes for the methyl-CpG binding protein 2 (MeCP2). Currently, MeCP2 is thought to act as a transcriptional repressor that couples DNA methylation and transcriptional silencing. The present study aimed to identify new target genes regulated by Mecp2 in a mouse model of RTT. Methodology/Principal Findings We have compared the gene expression profiles of wild type (WT) and Mecp2-null (KO) mice in three regions of the brain (cortex, midbrain, and cerebellum) by using cDNA microarrays. The results obtained were confirmed by quantitative real-time PCR. Subsequent chromatin immunoprecipitation assays revealed seven direct target genes of Mecp2 bound in vivo (Fkbp5, Mobp, Plagl1, Ddc, Mllt2h, Eya2, and S100a9), and three overexpressed genes due to an indirect effect of a lack of Mecp2 (Irak1, Prodh and Dlk1). The regions bound by Mecp2 were always methylated, suggesting the involvement of the methyl-CpG binding domain of the protein in the mechanism of interaction. Conclusions We identified new genes that are overexpressed in Mecp2-KO mice and are excellent candidate genes for involvement in various features of the neurological disease. Our results demonstrate new targets of MeCP2 and provide us with a better understanding of the underlying mechanisms of RTT. PMID:18989361

  1. Behavioral phenotype of maLPA1-null mice: increased anxiety-like behavior and spatial memory deficits

    PubMed Central

    Santin, L.J.; Bilbao, A.; Pedraza, C.; Matas-Rico, E.; López-Barroso, D.; Castilla-Ortega, E.; Sánchez-López, J.; Riquelme, R.; Varela-Nieto, I.; de la Villa, P.; Suardíaz, M.; Chun, J.; De Fonseca, F. Rodriguez; Estivill-Torrús, G.

    2016-01-01

    Lysophosphatidic acid (LPA) has emerged as a new regulatory molecule in the brain. Recently, some studies have demonstrated a role for this molecule and its LPA1 receptor in the regulation of plasticity and neurogenesis in the adult brain. However, no systematic studies have been conducted to investigate whether the LPA1 receptor is involved in behavior. Here we studied the phenotype of maLPA1–null mice, which bear a targeted deletion at the lpa1 locus, in a battery of tests examining neurologic performance, habituation in exploratory behavior in response to low and mild anxiety environments and spatial memory. MaLPA1-null mutants showed deficits in both olfaction and somesthesis, but not in retinal or auditory functions. Sensorimotor coordination was impaired only in the equilibrium and grasping reflexes. The mice also showed impairments in neuromuscular strength and analgesic response. No additional differences were observed in the rest of the tests used to study sensoriomotor orientation, limb reflexes, and coordinated limb use. At behavioral level, maLPA1-null mice showed an impaired exploration in the open field and increased anxiety-like response when exposed to the elevated plus maze. Furthermore, the mice exhibit impaired spatial memory retention and reduced use of spatial strategies in the Morris water maze. We propose that the LPA1 receptor may play a major role in both spatial memory and response to anxiety-like conditions. PMID:19689455

  2. Toll-Like Receptor 4 Mutant and Null Mice Retain Morphine-Induced Tolerance, Hyperalgesia, and Physical Dependence

    PubMed Central

    Mattioli, Theresa Alexandra; Leduc-Pessah, Heather; Skelhorne-Gross, Graham; Nicol, Christopher J. B.; Milne, Brian; Trang, Tuan; Cahill, Catherine M.

    2014-01-01

    The innate immune system modulates opioid-induced effects within the central nervous system and one target that has received considerable attention is the toll-like receptor 4 (TLR4). Here, we examined the contribution of TLR4 in the development of morphine tolerance, hyperalgesia, and physical dependence in two inbred mouse strains: C3H/HeJ mice which have a dominant negative point mutation in the Tlr4 gene rendering the receptor non-functional, and B10ScNJ mice which are TLR4 null mutants. We found that neither acute antinociceptive response to a single dose of morphine, nor the development of analgesic tolerance to repeated morphine treatment, was affected by TLR4 genotype. Likewise, opioid induced hyperalgesia and opioid physical dependence (assessed by naloxone precipitated withdrawal) were not altered in TLR4 mutant or null mice. We also examined the behavioural consequence of two stereoisomers of naloxone: (−) naloxone, an opioid receptor antagonist, and (+) naloxone, a purported antagonist of TLR4. Both stereoisomers of naloxone suppressed opioid induced hyperalgesia in wild-type control, TLR4 mutant, and TLR4 null mice. Collectively, our data suggest that TLR4 is not required for opioid-induced analgesic tolerance, hyperalgesia, or physical dependence. PMID:24824631

  3. Icariin inhibits atherosclerosis progress in Apoe null mice by downregulating CX3CR1 in macrophage.

    PubMed

    Wang, Yao; Wang, Yun-Shan; Song, Shu-Liang; Liang, Hao; Ji, Ai-Guo

    2016-02-19

    Horny Goat Weed is a commonly used in Chinese herbal medicine. And it is used in multiple kinds of diseases including cardiovascular diseases. Icariin is the major component isolated from Horny Goat Weed. It is reported to have lipid-lowering effect. In atherosclerosis, icariin attenuate the enhanced prothrombotic state independently of its lipid-lowering effects. However, its detail mechanism is remaining unclear. This study aimed to investigate the effect and mechanism of icariin on atherosclerosis. We performed gene expression profiling on icariin treated LPS-stimulated RAW264.7 and its control cells. Microarray analyses identified a list of genes significantly differentially expressed after icariin treated including downregulation of CX3CR1. Apoe null mice were assigned into 3 groups: control group, diet with 30 mg/kg/d icariin and diet with 60 mg/kg/d icariin. The results showed that icariin treatment significantly reduced lesion area and macrophage infiltration. Also icariin reduced CX3CR1 and CX3CL1 protein levels in the artery wall. In conclusion, icariin could be a potential anti-atherosclerosis agent by downregulating the expression of CX3CR1. PMID:26802470

  4. Docosahexaenoic acid supplementation fully restores fertility and spermatogenesis in male delta-6 desaturase-null mice

    PubMed Central

    Roqueta-Rivera, Manuel; Stroud, Chad K.; Haschek, Wanda M.; Akare, Sandeep J.; Segre, Mariangela; Brush, Richard S.; Agbaga, Martin-Paul; Anderson, Robert E.; Hess, Rex A.; Nakamura, Manabu T.

    2010-01-01

    Delta-6 desaturase-null mice (−/−) are unable to synthesize highly unsaturated fatty acids (HUFAs): arachidonic acid (AA), docosahexaenoic acid (DHA), and n6-docosapentaenoic acid (DPAn6). The −/− males exhibit infertility and arrest of spermatogenesis at late spermiogenesis. To determine which HUFA is essential for spermiogenesis, a diet supplemented with either 0.2% (w/w) AA or DHA was fed to wild-type (+/+) and −/− males at weaning until 16 weeks of age (n = 3–5). A breeding success rate of DHA-supplemented −/− was comparable to +/+. DHA-fed −/− showed normal sperm counts and spermiogenesis. Dietary AA was less effective in restoring fertility, sperm count, and spermiogenesis than DHA. Testis fatty acid analysis showed restored DHA in DHA-fed −/−, but DPAn6 remained depleted. In AA-fed −/−, AA was restored at the +/+ level, and 22:4n6, an AA elongated product, accumulated in testis. Cholesta-3,5-diene was present in testis of +/+ and DHA-fed −/−, whereas it diminished in −/− and AA-fed −/−, suggesting impaired sterol metabolism in these groups. Expression of spermiogenesis marker genes was largely normal in all groups. In conclusion, DHA was capable of restoring all observed impairment in male reproduction, whereas 22:4n6 formed from dietary AA may act as an inferior substitute for DHA. PMID:19690334

  5. Forelimb contractures and abnormal tendon collagen fibrillogenesis in fibulin-4 null mice.

    PubMed

    Markova, Dessislava Z; Pan, Te-Cheng; Zhang, Rui-Zhu; Zhang, Guiyun; Sasaki, Takako; Arita, Machiko; Birk, David E; Chu, Mon-Li

    2016-06-01

    Fibulin-4 is an extracellular matrix glycoprotein essential for elastic fiber formation. Mice deficient in fibulin-4 die perinatally because of severe pulmonary and vascular defects associated with the lack of intact elastic fibers. Patients with fibulin-4 mutations demonstrate similar defects, and a significant number die shortly after birth or in early childhood from cardiopulmonary failure. The patients also demonstrate skeletal and other systemic connective tissue abnormalities, including joint laxity and flexion contractures of the wrist. A fibulin-4 null mouse strain was generated and used to analyze the roles of fibulin-4 in tendon fibrillogenesis. This mouse model displayed bilateral forelimb contractures, in addition to pulmonary and cardiovascular defects. The forelimb and hindlimb tendons exhibited disruption in collagen fibrillogenesis in the absence of fibulin-4 as analyzed by transmission electron microscopy. Fewer fibrils were assembled, and fibrils were disorganized compared with wild-type controls. The organization of developing tenocytes and compartmentalization of the extracellular space was also disrupted. Fibulin-4 was co-localized with fibrillin-1 and fibrillin-2 in limb tendons by using immunofluorescence microscopy. Thus, fibulin-4 seems to play a role in regulating tendon collagen fibrillogenesis, in addition to its essential function in elastogenesis. PMID:26711913

  6. Deficiency of Glycine N-Methyltransferase Aggravates Atherosclerosis in Apolipoprotein E–Null Mice

    PubMed Central

    Chen, Chien-Yu; Ching, Li-Chieh; Liao, Yi-Jen; Yu, Yuan-Bin; Tsou, Chia-Yuan; Shyue, Song-Kun; Chen, Yi-Ming Arthur; Lee, Tzong-Shyuan

    2012-01-01

    The mechanism underlying the dysregulation of cholesterol metabolism and inflammation in atherogenesis is not understood fully. Glycine N-methyltransferase (GNMT) has been implicated in hepatic lipid metabolism and the pathogenesis of liver diseases. However, little is known about the significance of GNMT in atherosclerosis. We showed the predominant expression of GNMT in foamy macrophages of mouse atherosclerotic aortas. Genetic deletion of GNMT exacerbated the hyperlipidemia, inflammation and development of atherosclerosis in apolipoprotein E–deficient mice. In addition, ablation of GNMT in macrophages aggravated oxidized low-density lipoprotein-mediated cholesterol accumulation in macrophage foam cells by downregulating the expression of reverse cholesterol transporters including ATP-binding cassette transporters-A1 and G1 and scavenger receptor BI. Furthermore, tumor necrosis factor-α–induced inflammatory response was promoted in GNMT-null macrophages. Collectively, our data suggest that GNMT is a crucial regulator in cholesterol metabolism and in inflammation, and contributes to the pathogenesis of atherosclerosis. This finding may reveal a potential therapeutic target for atherosclerosis. PMID:22415010

  7. Molecular dynamics simulations highlight structural and functional alterations in deafness-related M34T mutation of connexin 26.

    PubMed

    Zonta, Francesco; Buratto, Damiano; Cassini, Chiara; Bortolozzi, Mario; Mammano, Fabio

    2014-01-01

    Mutations of the GJB2 gene encoding the connexin 26 (Cx26) gap junction protein, which is widely expressed in the inner ear, are the primary cause of hereditary non-syndromic hearing loss in several populations. The deafness-associated single amino acid substitution of methionine 34 (M34) in the first transmembrane helix (TM1) with a threonine (T) ensues in the production of mutant Cx26M34T channels that are correctly synthesized and assembled in the plasma membrane. However, mutant channels overexpressed in HeLa cells retain only 11% of the wild type unitary conductance. Here we extend and rationalize those findings by comparing wild type Cx26 (Cx26WT) and Cx26M34T mutant channels in silico, using molecular dynamics simulations. Our results indicate that the quaternary structure of the Cx26M34T hemichannel is altered at the level of the pore funnel due to the disruption of the hydrophobic interaction between M34 and tryptophan 3 (W3) in the N-terminal helix (NTH). Our simulations also show that external force stimuli applied to the NTHs can detach them from the inner wall of the pore more readily in the mutant than in the wild type hemichannel. These structural alterations significantly increase the free energy barrier encountered by permeating ions, correspondingly decreasing the unitary conductance of the Cx26M34T hemichannel. Our results accord with the proposal that the mutant resides most of the time in a low conductance state. However, the small displacement of the NTHs in our Cx26M34T hemichannel model is not compatible with the formation of a pore plug as in the related Cx26M34A mutant. PMID:24624091

  8. Molecular dynamics simulations highlight structural and functional alterations in deafness–related M34T mutation of connexin 26

    PubMed Central

    Zonta, Francesco; Buratto, Damiano; Cassini, Chiara; Bortolozzi, Mario; Mammano, Fabio

    2014-01-01

    Mutations of the GJB2 gene encoding the connexin 26 (Cx26) gap junction protein, which is widely expressed in the inner ear, are the primary cause of hereditary non-syndromic hearing loss in several populations. The deafness–associated single amino acid substitution of methionine 34 (M34) in the first transmembrane helix (TM1) with a threonine (T) ensues in the production of mutant Cx26M34T channels that are correctly synthesized and assembled in the plasma membrane. However, mutant channels overexpressed in HeLa cells retain only 11% of the wild type unitary conductance. Here we extend and rationalize those findings by comparing wild type Cx26 (Cx26WT) and Cx26M34T mutant channels in silico, using molecular dynamics simulations. Our results indicate that the quaternary structure of the Cx26M34T hemichannel is altered at the level of the pore funnel due to the disruption of the hydrophobic interaction between M34 and tryptophan 3 (W3) in the N–terminal helix (NTH). Our simulations also show that external force stimuli applied to the NTHs can detach them from the inner wall of the pore more readily in the mutant than in the wild type hemichannel. These structural alterations significantly increase the free energy barrier encountered by permeating ions, correspondingly decreasing the unitary conductance of the Cx26M34T hemichannel. Our results accord with the proposal that the mutant resides most of the time in a low conductance state. However, the small displacement of the NTHs in our Cx26M34T hemichannel model is not compatible with the formation of a pore plug as in the related Cx26M34A mutant. PMID:24624091

  9. Constitutive Androgen Receptor-Null Mice Are Sensitive to the Toxic Effects of Parathion: Association with Reduced Cytochrome P450-Mediated Parathion MetabolismS⃞

    PubMed Central

    Mota, Linda C.; Hernandez, Juan P.

    2010-01-01

    Constitutive androgen receptor (CAR) is activated by several chemicals and in turn regulates multiple detoxification genes. Our research demonstrates that parathion is one of the most potent, environmentally relevant CAR activators with an EC50 of 1.43 μM. Therefore, animal studies were conducted to determine whether CAR was activated by parathion in vivo. Surprisingly, CAR-null mice, but not wild-type (WT) mice, showed significant parathion-induced toxicity. However, parathion did not induce Cyp2b expression, suggesting that parathion is not a CAR activator in vivo, presumably because of its short half-life. CAR expression is also associated with the expression of several drug-metabolizing cytochromes P450 (P450). CAR-null mice demonstrate lower expression of Cyp2b9, Cyp2b10, Cyp2c29, and Cyp3a11 primarily, but not exclusively in males. Therefore, we incubated microsomes from untreated WT and CAR-null mice with parathion in the presence of esterase inhibitors to determine whether CAR-null mice show perturbed P450-mediated parathion metabolism compared with that in WT mice. The metabolism of parathion to paraoxon and p-nitrophenol (PNP) was reduced in CAR-null mice with male CAR-null mice showing reduced production of both paraoxon and PNP, and female CAR-null mice showing reduced production of only PNP. Overall, the data indicate that CAR-null mice metabolize parathion slower than WT mice. These results provide a potential mechanism for increased sensitivity of individuals with lower CAR activity such as newborns to parathion and potentially other chemicals due to decreased metabolic capacity. PMID:20573718

  10. Lumbar intervertebral disc degeneration associated with axial and radiating low back pain in ageing SPARC-null mice.

    PubMed

    Millecamps, Magali; Tajerian, Maral; Naso, Lina; Sage, E Helene; Stone, Laura S

    2012-06-01

    Chronic low back pain (LBP) is a complex, multifactorial disorder with unclear underlying mechanisms. In humans and rodents, decreased expression of secreted protein acidic rich in cysteine (SPARC) is associated with intervertebral disc (IVD) degeneration and signs of LBP. The current study investigates the hypothesis that IVD degeneration is a risk factor for chronic LBP. SPARC-null and age-matched control mice ranging from 6 to 78 weeks of age were evaluated in this study. X-ray and histologic analysis revealed reduced IVD height, increased wedging, and signs of degeneration (bulging and herniation). Cutaneous sensitivity to cold, heat, and mechanical stimuli were used as measures of referred (low back and tail) and radiating pain (hind paw). Region specificity was assessed by measuring icilin- and capsaicin-evoked behaviour after subcutaneous injection into the hind paw or upper lip. Axial discomfort was measured by the tail suspension and grip force assays. Motor impairment was determined by the accelerating rotarod. Physical function was evaluated by voluntary activity after axial strain or during ambulation with forced lateral flexion. SPARC-null mice developed (1) region-specific, age-dependent hypersensitivity to cold, icilin, and capsaicin (hind paw only), (2) axial discomfort, (3) motor impairment, and (4) reduced physical function. Morphine (6 mg/kg, i.p.) reduced cutaneous sensitivity and alleviated axial discomfort in SPARC-null mice. Ageing SPARC-null mice mirror many aspects of the complex and challenging nature of LBP in humans and incorporate both anatomic and functional components of the disease. The current study supports the hypothesis that IVD degeneration is a risk factor for chronic LBP. PMID:22414871

  11. PV-1 IS NEGATIVELY REGULATED BY VEGF IN THE LUNG OF CAV-1, BUT NOT CAV-2, NULL MICE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An N-glycosylated 60-kDa PV-1 protein that binds heparin was detected in mouse lung from a single mRNA transcript. In the absence of disulfide bond reduction PV-1 is detected as a dimer or large molecular weight oligomer. In the lung of Cav-1, but not Cav-2, null mice the amount of PV-1 protein is d...

  12. Lens transcriptome profile during cataract development in Mip-null mice.

    PubMed

    Bennett, Thomas M; Zhou, Yuefang; Shiels, Alan

    2016-09-16

    Major intrinsic protein or aquaporin-0 (MIP/AQP0) functions as a water channel and a cell-junction molecule in the vertebrate eye lens. Loss of MIP function in the lens leads to degraded optical quality and cataract formation by pathogenic mechanisms that are unclear. Here we have used microarray-hybridization analysis to detect lens transcriptome changes during cataract formation in mice that are functionally null for MIP (Mip-/-). In newborn Mip-/- lenses (P1) 11 genes were up-regulated and 18 were down-regulated (>2-fold, p=<0.05) and a similar number of genes was differentially regulated at P7. The most up-regulated genes (>6-fold) in the Mip-/- lens at P1 included those coding for a mitochondrial translocase (Timmdc1), a matrix metallopeptidase (Mmp2), a Rho GTPase-interacting protein (Ubxn11) and a transcription factor (Twist2). Apart from Mip, the most down-regulated genes (>4-fold) in the Mip-/- lens at P1 included those coding for a proteasome sub-unit (Psmd8), a ribonuclease (Pop4), and a heat-shock protein (Hspb1). Lens fiber cell degeneration in the Mip-/- lens was associated with increased numbers of TUNEL-positive cell nuclei and dramatically elevated levels of calpain-mediated proteolysis of αII-spectrin. However red-ox status, measured by glutathione and free-radical levels, was similar to that of wild-type. These data suggest that while relatively few genes (∼1.5% of the transcriptome) were differentially regulated >2-fold in the Mip-/- lens, calpain hyper-activation acts as a terminal pathogenic event during lens fiber cell death and cataract formation. PMID:27524245

  13. β3GnT2 null mice exhibit defective accessory olfactory bulb innervation.

    PubMed

    Henion, Timothy R; Madany, Pasil A; Faden, Ashley A; Schwarting, Gerald A

    2013-01-01

    Vomeronasal sensory neurons (VSNs) extend axons to the accessory olfactory bulb (AOB) where they form synaptic connections that relay pheromone signals to the brain. The projections of apical and basal VSNs segregate in the AOB into anterior (aAOB) and posterior (pAOB) compartments. Although some aspects of this organization exhibit fundamental similarities with the main olfactory system, the mechanisms that regulate mammalian vomeronasal targeting are not as well understood. In the olfactory epithelium (OE), the glycosyltransferase β3GnT2 maintains expression of axon guidance cues required for proper glomerular positioning and neuronal survival. We show here that β3GnT2 also regulates guidance and adhesion molecule expression in the vomeronasal system in ways that are partially distinct from the OE. In wildtype mice, ephrinA5(+) axons project to stereotypic subdomains in both the aAOB and pAOB compartments. This pattern is dramatically altered in β3GnT2(-/-) mice, where ephrinA5 is upregulated exclusively on aAOB axons. Despite this, apical and basal VSN projections remain strictly segregated in the null AOB, although some V2r1b axons that normally project to the pAOB inappropriately innervate the anterior compartment. These fibers appear to arise from ectopic expression of V2r1b receptors in a subset of apical VSNs. The homotypic adhesion molecules Kirrel2 and OCAM that facilitate axon segregation and glomerular compartmentalization in the main olfactory bulb are ablated in the β3GnT2(-/-) aAOB. This loss is accompanied by a two-fold increase in the total number of V2r1b glomeruli and a failure to form morphologically distinct glomeruli in the anterior compartment. These results identify a novel function for β3GnT2 glycosylation in maintaining expression of layer-specific vomeronasal receptors, as well as adhesion molecules required for proper AOB glomerular formation. PMID:23006775

  14. Sex-specific dysregulation of cysteine oxidation and the methionine and folate cycles in female cystathionine gamma-lyase null mice: a serendipitous model of the methylfolate trap.

    PubMed

    Jiang, Hua; Hurt, K Joseph; Breen, Kelsey; Stabler, Sally P; Allen, Robert H; Orlicky, David J; Maclean, Kenneth N

    2015-01-01

    In addition to its role in the endogenous synthesis of cysteine, cystathionine gamma-lyase (CGL) is a major physiological source of the vasorelaxant hydrogen sulfide. Cgl null mice are potentially useful for studying the influence of this compound upon vascular tone and endothelial function. Here, we confirm a previous report that female Cgl null mice exhibit an approximate 45-fold increase in plasma total homocysteine compared to wild type controls. This level of homocysteine is approximately 3.5-fold higher than that observed in male Cgl null mice and is essentially equivalent to that observed in mouse models of cystathionine beta synthase deficient homocystinuria. Cgl null mice of both sexes exhibited decreased expression of methylenetetrahydrofolate reductase and cysteinesulfinate decarboxylase compared to WT controls. Female Cgl null mice exhibited a sex-specific induction of betaine homocysteine S-methyltransferase and methionine adenosyltransferase 1, alpha and a 70% decrease in methionine synthase expression accompanied by significantly decreased plasma methionine. Decreased plasma cysteine levels in female Cgl null mice were associated with sex-specific dysregulation of cysteine dioxygenase expression. Comparative histological assessment between cystathionine beta-synthase and Cgl null mice indicated that the therapeutic potential of cystathionine against liver injury merits possible further investigation. Collectively, our data demonstrates the importance of considering sex when investigating mouse models of inborn errors of metabolism and indicate that while female Cgl null mice are of questionable utility for studying the physiological role of hydrogen sulfide, they could serve as a useful model for studying the consequences of methionine synthase deficiency and the methylfolate trap. PMID:26276101

  15. Sex-specific dysregulation of cysteine oxidation and the methionine and folate cycles in female cystathionine gamma-lyase null mice: a serendipitous model of the methylfolate trap

    PubMed Central

    Jiang, Hua; Hurt, K. Joseph; Breen, Kelsey; Stabler, Sally P.; Allen, Robert H.; Orlicky, David J.; Maclean, Kenneth N.

    2015-01-01

    ABSTRACT In addition to its role in the endogenous synthesis of cysteine, cystathionine gamma-lyase (CGL) is a major physiological source of the vasorelaxant hydrogen sulfide. Cgl null mice are potentially useful for studying the influence of this compound upon vascular tone and endothelial function. Here, we confirm a previous report that female Cgl null mice exhibit an approximate 45-fold increase in plasma total homocysteine compared to wild type controls. This level of homocysteine is approximately 3.5-fold higher than that observed in male Cgl null mice and is essentially equivalent to that observed in mouse models of cystathionine beta synthase deficient homocystinuria. Cgl null mice of both sexes exhibited decreased expression of methylenetetrahydrofolate reductase and cysteinesulfinate decarboxylase compared to WT controls. Female Cgl null mice exhibited a sex-specific induction of betaine homocysteine S-methyltransferase and methionine adenosyltransferase 1, alpha and a 70% decrease in methionine synthase expression accompanied by significantly decreased plasma methionine. Decreased plasma cysteine levels in female Cgl null mice were associated with sex-specific dysregulation of cysteine dioxygenase expression. Comparative histological assessment between cystathionine beta-synthase and Cgl null mice indicated that the therapeutic potential of cystathionine against liver injury merits possible further investigation. Collectively, our data demonstrates the importance of considering sex when investigating mouse models of inborn errors of metabolism and indicate that while female Cgl null mice are of questionable utility for studying the physiological role of hydrogen sulfide, they could serve as a useful model for studying the consequences of methionine synthase deficiency and the methylfolate trap. PMID:26276101

  16. Integrin α1-null Mice Exhibit Improved Fatty Liver When Fed a High Fat Diet Despite Severe Hepatic Insulin Resistance*

    PubMed Central

    Williams, Ashley S.; Kang, Li; Zheng, Jenny; Grueter, Carrie; Bracy, Deanna P.; James, Freyja D.; Pozzi, Ambra; Wasserman, David H.

    2015-01-01

    Hepatic insulin resistance is associated with increased collagen. Integrin α1β1 is a collagen-binding receptor expressed on hepatocytes. Here, we show that expression of the α1 subunit is increased in hepatocytes isolated from high fat (HF)-fed mice. To determine whether the integrin α1 subunit protects against impairments in hepatic glucose metabolism, we analyzed glucose tolerance and insulin sensitivity in HF-fed integrin α1-null (itga1−/−) and wild-type (itga1+/+) littermates. Using the insulin clamp, we found that insulin-stimulated hepatic glucose production was suppressed by ∼50% in HF-fed itga1+/+ mice. In contrast, it was not suppressed in HF-fed itga1−/− mice, indicating severe hepatic insulin resistance. This was associated with decreased hepatic insulin signaling in HF-fed itga1−/− mice. Interestingly, hepatic triglyceride and diglyceride contents were normalized to chow-fed levels in HF-fed itga1−/− mice. This indicates that hepatic steatosis is dissociated from insulin resistance in HF-fed itga1−/− mice. The decrease in hepatic lipid accumulation in HF-fed itga1−/− mice was associated with altered free fatty acid metabolism. These studies establish a role for integrin signaling in facilitating hepatic insulin action while promoting lipid accumulation in mice challenged with a HF diet. PMID:25593319

  17. Over-expression of hedgehog signaling is associated with epidermal tumor formation in vitamin D receptor null mice

    PubMed Central

    Teichert, Arnaud; Elalieh, Hashem; Elias, Peter; Welsh, JoEllen; Bikle, Daniel D.

    2011-01-01

    The vitamin D receptor (VDR) ligand, 1,25(OH)2D3, reduces proliferation and enhances differentiation and thus has been investigated for a role in preventing or treating cancer. Mice deficient for the VDR display a hyperproliferative response in the hair follicle and epidermis and decreased epidermal differentiation. Unlike their wild type littermates, when treated with 7,12 dimethylbenzanthracene (DMBA) or UVB, they develop skin tumors, including some characteristic of over-expression of the hedgehog (Hh) pathway. Both the epidermis and utricles of the VDR null animals over-express elements of the Hh pathway [Sonic Hedgehog (Shh, 2.02 fold), Patched1 1.58 fold, Smoothened 3.54 fold, Gli1 1.17 fold, and Gli2 1.66 fold]. This over-expression occurs at an age (11 weeks) where epidermal hyperproliferation is most visible and is spatially controlled in the epidermis. DMBA or UVB induced tumors in the VDR null mice also over-express elements of this pathway. Moreover, 1,25(OH)2D3 down-regulates the expression of some members of the Hh pathway in an epidermal explants culture system, suggesting a direct regulation by 1,25(OH)2D3. Our results suggest that increased expression of Shh in the keratinocytes of the VDR null animal activates the Hh pathway, predisposing the skin to the development of both malignant and benign epidermal neoplasms. PMID:21814234

  18. Reduction of aberrant NF-κB signalling ameliorates Rett syndrome phenotypes in Mecp2-null mice

    PubMed Central

    Kishi, Noriyuki; MacDonald, Jessica L.; Ye, Julia; Molyneaux, Bradley J.; Azim, Eiman; Macklis, Jeffrey D.

    2016-01-01

    Mutations in the transcriptional regulator Mecp2 cause the severe X-linked neurodevelopmental disorder Rett syndrome (RTT). In this study, we investigate genes that function downstream of MeCP2 in cerebral cortex circuitry, and identify upregulation of Irak1, a central component of the NF-κB pathway. We show that overexpression of Irak1 mimics the reduced dendritic complexity of Mecp2-null cortical callosal projection neurons (CPN), and that NF-κB signalling is upregulated in the cortex with Mecp2 loss-of-function. Strikingly, we find that genetically reducing NF-κB signalling in Mecp2-null mice not only ameliorates CPN dendritic complexity but also substantially extends their normally shortened lifespan, indicating broader roles for NF-κB signalling in RTT pathogenesis. These results provide new insight into both the fundamental neurobiology of RTT, and potential therapeutic strategies via NF-κB pathway modulation. PMID:26821816

  19. Reduction of aberrant NF-κB signalling ameliorates Rett syndrome phenotypes in Mecp2-null mice.

    PubMed

    Kishi, Noriyuki; MacDonald, Jessica L; Ye, Julia; Molyneaux, Bradley J; Azim, Eiman; Macklis, Jeffrey D

    2016-01-01

    Mutations in the transcriptional regulator Mecp2 cause the severe X-linked neurodevelopmental disorder Rett syndrome (RTT). In this study, we investigate genes that function downstream of MeCP2 in cerebral cortex circuitry, and identify upregulation of Irak1, a central component of the NF-κB pathway. We show that overexpression of Irak1 mimics the reduced dendritic complexity of Mecp2-null cortical callosal projection neurons (CPN), and that NF-κB signalling is upregulated in the cortex with Mecp2 loss-of-function. Strikingly, we find that genetically reducing NF-κB signalling in Mecp2-null mice not only ameliorates CPN dendritic complexity but also substantially extends their normally shortened lifespan, indicating broader roles for NF-κB signalling in RTT pathogenesis. These results provide new insight into both the fundamental neurobiology of RTT, and potential therapeutic strategies via NF-κB pathway modulation. PMID:26821816

  20. Enhancement of postsynaptic GABAA and extrasynaptic NMDA receptor-mediated responses in the barrel cortex of Mecp2-null mice.

    PubMed

    Lo, Fu-Sun; Blue, Mary E; Erzurumlu, Reha S

    2016-03-01

    Rett syndrome (RTT) is a neurodevelopmental disorder that results from mutations in the X-linked gene for methyl-CpG-binding protein 2 (MECP2). The underlying cellular mechanism for the sensory deficits in patients with RTT is largely unknown. This study used the Bird mouse model of RTT to investigate sensory thalamocortical synaptic transmission in the barrel cortex of Mecp2-null mice. Electrophysiological results showed an excitation/inhibition imbalance, biased toward inhibition, due to an increase in efficacy of postsynaptic GABAA receptors rather than alterations in inhibitory network and presynaptic release properties. Enhanced inhibition impaired the transmission of tonic sensory signals from the thalamus to the somatosensory cortex. Previous morphological studies showed an upregulation of NMDA receptors in the neocortex of both RTT patients and Mecp2-null mice at early ages [Blue ME, Naidu S, Johnston MV. Ann Neurol 45: 541-545, 1999; Blue ME, Kaufmann WE, Bressler J, Eyring C, O'Driscoll C, Naidu S, Johnston MV. Anat Rec (Hoboken) 294: 1624-1634, 2011]. Although AMPA and NMDA receptor-mediated excitatory synaptic transmission was not altered in the barrel cortex of Mecp2-null mice, extrasynaptic NMDA receptor-mediated responses increased markedly. These responses were blocked by memantine, suggesting that extrasynaptic NMDA receptors play an important role in the pathogenesis of RTT. The results suggest that enhancement of postsynaptic GABAA and extrasynaptic NMDA receptor-mediated responses may underlie impaired somatosensation and that pharmacological blockade of extrasynaptic NMDA receptors may have therapeutic value for RTT. PMID:26683074

  1. Cytochrome P450 Regulation by α-Tocopherol in Pxr-Null and PXR-Humanized Mice

    PubMed Central

    Johnson, Caroline H.; Bonzo, Jessica A.; Cheng, Jie; Krausz, Kristopher W.; Kang, Dong Wook; Luecke, Hans; Idle, Jeffrey R.

    2013-01-01

    The pregnane X receptor (PXR) has been postulated to play a role in the metabolism of α-tocopherol owing to the up-regulation of hepatic cytochrome P450 (P450) 3A in human cell lines and murine models after α-tocopherol treatment. However, in vivo studies confirming the role of PXR in α-tocopherol metabolism in humans presents significant difficulties and has not been performed. PXR-humanized (hPXR), wild-type, and Pxr-null mouse models were used to determine whether α-tocopherol metabolism is influenced by species-specific differences in PXR function in vivo. No significant difference in the concentration of the major α-tocopherol metabolites was observed among the hPXR, wild-type, and Pxr-null mice through mass spectrometry-based metabolomics. Gene expression analysis revealed significantly increased expression of Cyp3a11 as well as several other P450s only in wild-type mice, suggesting species-specificity for α-tocopherol activation of PXR. Luciferase reporter assay confirmed activation of mouse PXR by α-tocopherol. Analysis of the Cyp2c family of genes revealed increased expression of Cyp2c29, Cyp2c37, and Cyp2c55 in wild-type, hPXR, and Pxr-null mice, which suggests PXR-independent induction of Cyp2c gene expression. This study revealed that α-tocopherol is a partial agonist of PXR and that PXR is necessary for Cyp3a induction by α-tocopherol. The implications of a novel role for α-tocopherol in Cyp2c gene regulation are also discussed. PMID:23160821

  2. Polymicrobial Oral Infection with Four Periodontal Bacteria Orchestrates a Distinct Inflammatory Response and Atherosclerosis in ApoE null Mice.

    PubMed

    Chukkapalli, Sasanka S; Velsko, Irina M; Rivera-Kweh, Mercedes F; Zheng, Donghang; Lucas, Alexandra R; Kesavalu, Lakshmyya

    2015-01-01

    Periodontal disease (PD) develops from a synergy of complex subgingival oral microbiome, and is linked to systemic inflammatory atherosclerotic vascular disease (ASVD). To investigate how a polybacterial microbiome infection influences atherosclerotic plaque progression, we infected the oral cavity of ApoE null mice with a polybacterial consortium of 4 well-characterized periodontal pathogens, Porphyromonas gingivalis, Treponema denticola, Tannerealla forsythia and Fusobacterium nucleatum, that have been identified in human atherosclerotic plaque by DNA screening. We assessed periodontal disease characteristics, hematogenous dissemination of bacteria, peripheral T cell response, serum inflammatory cytokines, atherosclerosis risk factors, atherosclerotic plaque development, and alteration of aortic gene expression. Polybacterial infections have established gingival colonization in ApoE null hyperlipidemic mice and displayed invasive characteristics with hematogenous dissemination into cardiovascular tissues such as the heart and aorta. Polybacterial infection induced significantly higher levels of serum risk factors oxidized LDL (p < 0.05), nitric oxide (p < 0.01), altered lipid profiles (cholesterol, triglycerides, Chylomicrons, VLDL) (p < 0.05) as well as accelerated aortic plaque formation in ApoE null mice (p < 0.05). Periodontal microbiome infection is associated with significant decreases in Apoa1, Apob, Birc3, Fga, FgB genes that are associated with atherosclerosis. Periodontal infection for 12 weeks had modified levels of inflammatory molecules, with decreased Fas ligand, IL-13, SDF-1 and increased chemokine RANTES. In contrast, 24 weeks of infection induced new changes in other inflammatory molecules with reduced KC, MCSF, enhancing GM-CSF, IFNγ, IL-1β, IL-13, IL-4, IL-13, lymphotactin, RANTES, and also an increase in select inflammatory molecules. This study demonstrates unique differences in the host immune response to a polybacterial periodontal

  3. Increased primary tumor growth in mice null for β3- or β3/β5-integrins or selectins

    PubMed Central

    Taverna, Daniela; Moher, Heather; Crowley, Denise; Borsig, Lubor; Varki, Ajit; Hynes, Richard O.

    2004-01-01

    Expression of αvβ3- or αvβ5-integrins and selectins is widespread on blood cells and endothelial cells. Here we report that human tumor cells injected s.c. into mice lacking β3- or β3/β5-integrins or various selectins show enhanced tumor growth compared with growth in control mice. There was increased angiogenesis in mice lacking β3-integrins, but no difference in structure of the vessels was observed by histology or by staining for NG2 and smooth muscle actin in pericytes. Bone marrow transplants suggest that the absence of β3-integrins on bone marrow-derived host cells contributes to the enhanced tumor growth in β3-null mice, although few, if any, bone marrow-derived endothelial cells were found in the tumor vasculature. Tumor growth also was affected by bone marrow-derived cells in mice lacking any one or all three selectins, implicating both leukocyte and endothelial selectins in tumor suppression. Reduced infiltration of macrophages was observed in tumors grown in mice lacking either β3-integrins or selectins. These results implicate cells of the innate immune system, macrophages or perhaps natural killer cells, in each case dependent on integrins and selectins, in tumor suppression. PMID:14718670

  4. Age-related and depot-specific changes in white adipose tissue of growth hormone receptor-null mice.

    PubMed

    Sackmann-Sala, Lucila; Berryman, Darlene E; Lubbers, Ellen R; Zhang, Han; Vesel, Clare B; Troike, Katie M; Gosney, Elahu S; List, Edward O; Kopchick, John J

    2014-01-01

    Growth hormone receptor-null (GHR(-/-)) mice are dwarf, insulin sensitive, and long-lived in spite of increased adiposity. However, their adiposity is not uniform, with select white adipose tissue (WAT) depots enlarged. To study WAT depot-specific effects on insulin sensitivity and life span, we analyzed individual WAT depots of 12- and 24-month-old GHR(-) (/-) and wild-type (WT) mice, as well as their plasma levels of selected hormones. Adipocyte sizes and plasma insulin, leptin, and adiponectin levels decreased with age in both GHR(-) (/-) and WT mice. Two-dimensional gel electrophoresis proteomes of WAT depots were similar among groups, but several proteins involved in endocytosis and/or cytoskeletal organization (Ehd2, S100A10, actin), anticoagulation (S100A10, annexin A5), and age-related conditions (alpha2-macroglobulin, apolipoprotein A-I, transthyretin) showed significant differences between genotypes. Because Ehd2 may regulate endocytosis of Glut4, we measured Glut4 levels in the WAT depots of GHR(-) (/-) and WT mice. Inguinal WAT of 12-month-old GHR(-) (/-) mice displayed lower levels of Glut4 than WT. Overall, the protein changes detected in this study offer new insights into possible mechanisms contributing to enhanced insulin sensitivity and extended life span in GHR(-) (/-) mice. PMID:23873966

  5. Age-Related and Depot-Specific Changes in White Adipose Tissue of Growth Hormone Receptor-Null Mice

    PubMed Central

    2014-01-01

    Growth hormone receptor-null (GHR−/−) mice are dwarf, insulin sensitive, and long-lived in spite of increased adiposity. However, their adiposity is not uniform, with select white adipose tissue (WAT) depots enlarged. To study WAT depot–specific effects on insulin sensitivity and life span, we analyzed individual WAT depots of 12- and 24-month-old GHR− /− and wild-type (WT) mice, as well as their plasma levels of selected hormones. Adipocyte sizes and plasma insulin, leptin, and adiponectin levels decreased with age in both GHR− /− and WT mice. Two-dimensional gel electrophoresis proteomes of WAT depots were similar among groups, but several proteins involved in endocytosis and/or cytoskeletal organization (Ehd2, S100A10, actin), anticoagulation (S100A10, annexin A5), and age-related conditions (alpha2-macroglobulin, apolipoprotein A-I, transthyretin) showed significant differences between genotypes. Because Ehd2 may regulate endocytosis of Glut4, we measured Glut4 levels in the WAT depots of GHR− /− and WT mice. Inguinal WAT of 12-month-old GHR− /− mice displayed lower levels of Glut4 than WT. Overall, the protein changes detected in this study offer new insights into possible mechanisms contributing to enhanced insulin sensitivity and extended life span in GHR− /− mice. PMID:23873966

  6. Corneal Opacity in Lumican-Null Mice: Defects in Collagen Fibril Structure and Packing in the Posterior Stroma

    PubMed Central

    Chakravarti, Shukti; Petroll, W. Matthew; Hassell, John R.; Jester, James V.; Lass, Jonathan H.; Paul, Jennifer; Birk, David E.

    2015-01-01

    Purpose Gene targeted lumican-null mutants (lumtm1sc/lumtm1sc) have cloudy corneas with abnormally thick collagen fibrils. The purpose of the present study was to analyze the loss of transparency quantitatively and to define the associated corneal collagen fibril and stromal defects. Methods Backscattering of light, a function of corneal haze and opacification, was determined regionally using in vivo confocal microscopy in lumican-deficient and wild-type control mice. Fibril organization and structure were analyzed using transmission electron microscopy. Biochemical approaches were used to quantify glycosaminoglycan contents. Lumican distribution in the cornea was elucidated immunohistochemically. Results Compared with control stromas, lumican-deficient stromas displayed a threefold increase in backscattered light with maximal increase confined to the posterior stroma. Confocal microscopy through-focusing (CMTF) measurement profiles also indicated a 40% reduction in stromal thickness in the lumican-null mice. Transmission electron microscopy indicated significant collagen fibril abnormalities in the posterior stroma, with the anterior stroma remaining relatively unremarkable. The lumican-deficient posterior stroma displayed a pronounced increase in fibril diameter, large fibril aggregates, altered fibril packing, and poor lamellar organization. Immunostaining of wild-type corneas demonstrated high concentrations of lumican in the posterior stroma. Biochemical assessment of keratan sulfate (KS) content of whole eyes revealed a 25% reduction in KS content in the lumican-deficient mice. Conclusions The structural defects and maximum backscattering of light clearly localized to the posterior stroma of lumican-deficient mice. In normal mice, an enrichment of lumican was observed in the posterior stroma compared with that in the anterior stroma. Taken together, these observations indicate a key role for lumican in the posterior stroma in maintaining normal fibril

  7. A comparison of the metabolism of midazolam in C57BL/6J and hepatic reductase null (HRN) mice.

    PubMed

    Grimsley, Aidan; Foster, Alison; Gallagher, Richard; Hutchison, Michael; Lundqvist, Anders; Pickup, Kathryn; Wilson, Ian D; Samuelsson, Kristin

    2014-12-15

    The hepatic cytochrome P450 reductase null (HRN) mouse, which has no functional hepatic Cyp P450s, may represent a useful model for examining extra-hepatic P450-related oxidative metabolism. Here the pharmacokinetics and metabolic fate of midazolam, a drug known to undergo such extra-hepatic metabolism, have been investigated in the HRN mouse and compared with a phenotypically normal strain (C57BL/6J). In addition, the effects of co-administration of the pan-P450 inhibitor 1'-aminobenzotriazole (ABT) on the metabolic profile have been compared in both strains. Significant pharmacokinetic differences for midazolam were observed between the two strains of mice with the HRN mice showing lower circulating concentrations of 1'-hydroxymidazolam but higher concentrations of 1'-hydroxymidazolam-O-glucuronide. A significant increase in midazolam exposure was seen upon ABT exposure for both strains of mice, but no differences in the area under the concentration time curves (AUC) for the monitored metabolites were observed. Although oxidative metabolism of midazolam was not abolished, significant decreases in 1'-hydroxymidazolam formation ratios were observed for both strains of mice exposed to ABT. Metabolite profiling of blood and bile showed a number of qualitative and quantitative differences between HRN and normal mice. These differences in midazolam metabolism between the two strains of mice clearly demonstrate the role that liver P450 enzymes play in the murine metabolism of midazolam. The fate of the compound in the HRN mice shows the importance of extrahepatic metabolism and also showed that these mice appear to be more capable of forming circulating phase II glucuronides than the normal strain. PMID:25450676

  8. Liver specific expression of Cu/ZnSOD extends the lifespan of Sod1 null mice

    PubMed Central

    Zhang, Yiqiang; Liu, Yuhong; Walsh, Michael; Bokov, Alex; Ikeno, Yuji; Jang, Young C.; Perez, Viviana I.; Van Remmen, Holly; Richardson, Arlan

    2016-01-01

    Genetic ablation of CuZn-superoxide dismutase (Sod1) in mice (Sod1−/− mice) leads to shortened lifespan with a dramatic increase in hepatocellular carcinoma and accelerated aging phenotypes, including early onset sarcopenia. To study the tissue specific effects of oxidative stress in the Sod1−/− mice, we generated mice that only express the human SOD1 gene specifically in the liver of Sod1−/− mice (Sod1−/−/hSOD1alb mice). Expression of hSOD1 in the liver of Sod1−/− mice improved liver function, reduced oxidative damage in liver, and partially restored the expression of several genes involved in tumorigenesis, which are abnormally expressed in the livers of the Sod1−/− mice. However, liver specific expression of hSOD1 did not prevent the loss of body weight and muscle mass and alterations in the structure of neuromuscular junctions. The expression of hSOD1 in the liver of Sod1−/− mice significantly improved the lifespan of Sod1−/− mice; however, the lifespan of the Sod1−/−/hSOD1alb mice was still significantly shorter than wild type mice. PMID:26839948

  9. Pharmacological treatment with mirtazapine rescues cortical atrophy and respiratory deficits in MeCP2 null mice

    PubMed Central

    Bittolo, Tamara; Raminelli, Carlo Antonio; Deiana, Chiara; Baj, Gabriele; Vaghi, Valentina; Ferrazzo, Sara; Bernareggi, Annalisa; Tongiorgi, Enrico

    2016-01-01

    Loss of MeCP2 (Methyl CpG binding protein 2) in Rett syndrome (RTT) causes brain weight decrease, shrinkage of the cortex with reduced dendritic arborization, behavioral abnormalities, seizures and cardio-respiratory complications. The observed monoamine neurotransmitters reduction in RTT suggested antidepressants as a possible therapy. We treated MeCP2-null mice from postnatal-day 28 for two weeks with desipramine, already tested in RTT, or mirtazapine, an antidepressant with limited side-effects, known to promote GABA release. Mirtazapine was more effective than desipramine in restoring somatosensory cortex thickness by fully rescuing pyramidal neurons dendritic arborization and spine density. Functionally, mirtazapine treatment normalized heart rate, breath rate, anxiety levels, and eliminated the hopping behavior observed in MeCP2-null mice, leading to improved phenotypic score. These morphological and functional effects of mirtazapine were accompanied by reestablishment of the GABAergic and glutamatergic receptor activity recorded in cortex and brainstem tissues. Thus, mirtazapine can represent a new potential pharmacological treatment for the Rett syndrome. PMID:26806603

  10. Renoprotective Effects of Vitex megapotamica (Spreng.) Moldenke in C57BL/6 LDLr-Null Mice Undergoing High Fat Diet

    PubMed Central

    Araújo, Valdinei de Oliveira; Gasparotto, Francielly Mourão; Pires, Vanessa Aranega; Maciel, Aline Antunes; Ortmann, Caroline Flach; Cardozo Junior, Euclides Lara; Lourenço, Emerson Luiz Botelho; Gasparotto Junior, Arquimedes

    2015-01-01

    Although Vitex megapotamica (Spreng.) Moldenke is used in Brazilian folk medicine as hypolipidemic drug no study has been conducted to evaluate the effects of this species in an experimental model of atherosclerosis. So, the aim of this study was to evaluate the possible renoprotective activity of methanolic extract obtained from Vitex megapotamica (MEVM) using C57BL/6 LDLr-null mice submitted to high fat diet (HFD). MEVM was orally administered at doses of 30, 100, and 300 mg/kg, for three weeks, starting from the 2nd week of HFD. Systolic blood pressure (SBP) and diuretic activity were measured weekly. At the end of experiments the serum lipids, atherogenic index serum (AIS), oxidative stress, and markers of renal function were determined. HFD induced a significant increase in the systolic blood pressure, dyslipidemia, increase in AIS, and lipid peroxidation accompanied by an important reduction in renal function. Treatment with MEVM was able to prevent increase in SBP, total cholesterol, triglycerides, AIS, urea, and creatinine levels in LDLr-null mice. These effects were accompanied by a significant reduction in oxidative stress and renal injury. The data reported here support the potential of Vitex megapotamica as candidate to be an herbal medicine used in cardiovascular or renal diseases. PMID:25788962

  11. Pharmacological treatment with mirtazapine rescues cortical atrophy and respiratory deficits in MeCP2 null mice.

    PubMed

    Bittolo, Tamara; Raminelli, Carlo Antonio; Deiana, Chiara; Baj, Gabriele; Vaghi, Valentina; Ferrazzo, Sara; Bernareggi, Annalisa; Tongiorgi, Enrico

    2016-01-01

    Loss of MeCP2 (Methyl CpG binding protein 2) in Rett syndrome (RTT) causes brain weight decrease, shrinkage of the cortex with reduced dendritic arborization, behavioral abnormalities, seizures and cardio-respiratory complications. The observed monoamine neurotransmitters reduction in RTT suggested antidepressants as a possible therapy. We treated MeCP2-null mice from postnatal-day 28 for two weeks with desipramine, already tested in RTT, or mirtazapine, an antidepressant with limited side-effects, known to promote GABA release. Mirtazapine was more effective than desipramine in restoring somatosensory cortex thickness by fully rescuing pyramidal neurons dendritic arborization and spine density. Functionally, mirtazapine treatment normalized heart rate, breath rate, anxiety levels, and eliminated the hopping behavior observed in MeCP2-null mice, leading to improved phenotypic score. These morphological and functional effects of mirtazapine were accompanied by reestablishment of the GABAergic and glutamatergic receptor activity recorded in cortex and brainstem tissues. Thus, mirtazapine can represent a new potential pharmacological treatment for the Rett syndrome. PMID:26806603

  12. QUANTIFICATION OF RESERVE POOL DOPAMINE IN METHIONINE SULFOXIDE REDUCTASE A NULL MICE

    PubMed Central

    Ortiz, Andrea N.; Oien, Derek B.; Moskovitz, Jackob; Johnson, Michael A.

    2012-01-01

    Methionine sulfoxide reductase A knockout (MsrA−/−) mice, which serve as a potential model for neurodegeneration, suffer from increased oxidative stress and have previously been found to have chronically elevated brain dopamine content levels relative to control mice. Additionally, these high levels parallel increased presynaptic dopamine release. In this work, fast-scan cyclic voltammetry at carbon-fiber microelectrodes was used to quantify striatal reserve pool dopamine in knockout mice and wild-type control mice. Reserve pool dopamine efflux, induced by amphetamine, was measured in brain slices from knockout and wild type mice in the presence of α-methyl-p-tyrosine, a dopamine synthesis inhibitor. Additionally, the stimulated release of reserve pool dopamine, mobilized by cocaine, was measured. Both efflux and stimulated release measurements were enhanced in slices from knockout mice, suggesting that these mice have greater reserve pool dopamine stores than wild-type and that these stores are effectively mobilized. Moreover, dopamine transporter labeling data indicate that the difference in measured dopamine efflux was likely not caused by altered dopamine transporter protein expression. Additionally, slices from MsrA−/− and wild-type mice were equally responsive to increasing extracellular calcium concentrations, suggesting that potential differences in either calcium entry or intracellular calcium handling are not responsible for increased reserve pool dopamine release. Collectively, these results demonstrate that MsrA−/− knockout mice maintain a larger dopamine reserve pool than wild-type control mice, and that this pool is readily mobilized. PMID:21219974

  13. Generation of rac3 Null Mutant Mice: Role of Rac3 in Bcr/Abl-Caused Lymphoblastic Leukemia

    PubMed Central

    Cho, Young Jin; Zhang, Bin; Kaartinen, Vesa; Haataja, Leena; de Curtis, Ivan; Groffen, John; Heisterkamp, Nora

    2005-01-01

    Numerous studies indirectly implicate Rac GTPases in cancer. To investigate if Rac3 contributes to normal or malignant cell function, we generated rac3 null mutants through gene targeting. These mice were viable, fertile, and lacked an obvious external phenotype. This shows Rac3 function is dispensable for embryonic development. Bcr/Abl is a deregulated tyrosine kinase that causes chronic myelogenous leukemia and Ph-positive acute lymphoblastic leukemia in humans. Vav1, a hematopoiesis-specific exchange factor for Rac, was constitutively tyrosine phosphorylated in primary lymphomas from Bcr/Abl P190 transgenic mice, suggesting inappropriate Rac activation. rac3 is expressed in these malignant hematopoietic cells. Using lysates from BCR/ABL transgenic mice that express or lack rac3, we detected the presence of activated Rac3 but not Rac1 or Rac2 in the malignant precursor B-lineage lymphoblasts. In addition, in female P190 BCR/ABL transgenic mice, lack of rac3 was associated with a longer average survival. These data are the first to directly show a stimulatory role for Rac in leukemia in vivo. Moreover, our data suggest that interference with Rac3 activity, for example, by using geranyl-geranyltransferase inhibitors, may provide a positive clinical benefit for patients with Ph-positive acute lymphoblastic leukemia. PMID:15964830

  14. Alzheimer's disease-like impaired cognition in endothelial-specific megalin-null mice.

    PubMed

    Dietrich, Marcelo; Antequera, Desiree; Pascual, Consuelo; Castro, Nerea; Bolos, Marta; Carro, Eva

    2014-01-01

    Megalin has been suggested to be involved in Alzheimer's disease (AD), mediating blood-brain barrier (BBB) transport of multiple ligands, including amyloid-β peptide (Aβ), but also neuroprotective factors. Because no transgenic model is currently available to study this concept, we have obtained transgenic mice blocking megalin expression at the BBB. These endothelial megalin deficient (EMD) mice developed increased anxiety behavior and impaired learning ability and recognition memory, similar to symptoms described in AD. Degenerating neurons were also observed in the cerebral cortex of EMD mice. In view of our findings we suggest that, in mice, megalin deficiency at the BBB leads to neurodegeneration. PMID:24254699

  15. Decreased bile-acid synthesis in livers of hepatocyte-conditional NADPH-cytochrome P450 reductase-null mice results in increased bile acids in serum.

    PubMed

    Cheng, Xingguo; Zhang, Youcai; Klaassen, Curtis D

    2014-10-01

    NADPH-cytochrome P450 reductase (Cpr) is essential for the function of microsomal cytochrome P450 monooxygenases (P450), including those P450s involved in bile acid (BA) synthesis. Mice with hepatocyte-specific deletion of NADPH-cytochrome P450 reductase (H-Cpr-null) have been engineered to understand the in vivo function of hepatic P450s in the metabolism of xenobiotics and endogenous compounds. However, the impact of hepatic Cpr on BA homeostasis is not clear. The present study revealed that H-Cpr-null mice had a 60% decrease in total BA concentration in liver, whereas the total BA concentration in serum was almost doubled. The decreased level of cholic acid (CA) in both serum and livers of H-Cpr-null mice is likely due to diminished enzyme activity of Cyp8b1 that is essential for CA biosynthesis. Feedback mechanisms responsible for the reduced liver BA concentrations and/or increased serum BA concentrations in H-Cpr-null mice included the following: 1) enhanced alternative BA synthesis pathway, as evidenced by the fact that classic BA synthesis is diminished but chenodeoxycholic acid still increases in both serum and livers of H-Cpr-null mice; 2) inhibition of farnesoid X receptor activation, which increased the mRNA of Cyp7a1 and 8b1; 3) induction of intestinal BA transporters to facilitate BA absorption from the intestine to the circulation; 4) induction of hepatic multidrug resistance-associated protein transporters to increase BA efflux from the liver to blood; and 5) increased generation of secondary BAs. In summary, the present study reveals an important contribution of the alternative BA synthesis pathway and BA transporters in regulating BA concentrations in H-Cpr-null mice. PMID:25034404

  16. Prohormone convertase 2 (PC2) null mice have increased mu opioid receptor levels accompanied by altered morphine-induced antinociception, tolerance and dependence.

    PubMed

    Lutfy, K; Parikh, D; Lee, D L; Liu, Y; Ferrini, M G; Hamid, A; Friedman, T C

    2016-08-01

    Chronic morphine treatment increases the levels of prohormone convertase 2 (PC2) in brain regions involved in nociception, tolerance and dependence. Thus, we tested if PC2 null mice exhibit altered morphine-induced antinociception, tolerance and dependence. PC2 null mice and their wild-type controls were tested for baseline hot plate latency, injected with morphine (1.25-10mg/kg) and tested for antinociception 30min later. For tolerance studies, mice were tested in the hot plate test before and 30min following morphine (5mg/kg) on day 1. Mice then received an additional dose so that the final dose of morphine was 10mg/kg on this day. On days 2-4, mice received additional doses of morphine (20, 40 and 80mg/kg on days 1, 2, 3, and 4, respectively). On day 5, mice were tested in the hot plate test before and 30min following morphine (5mg/kg). For withdrawal studies, mice were treated with the escalating doses of morphine (10, 20, 40 and 80mg/kg) for 4days, implanted with a morphine pellet on day 5 and 3 days later injected with naloxone (1mg/kg) and signs of withdrawal were recorded. Morphine dose-dependently induced antinociception and the magnitude of this response was greater in PC2 null mice. Tolerance to morphine was observed in wild-type mice and this phenomenon was blunted in PC2 null mice. Withdrawal signs were also reduced in PC2 null mice. Immunohistochemical studies showed up-regulation of the mu opioid receptor (MOP) protein expression in the periaqueductal gray area, ventral tegmental area, lateral hypothalamus, medial hypothalamus, nucleus accumbens, and somatosensory cortex in PC2 null mice. Likewise, naloxone specific binding was increased in the brains of these mice compared to their wild-type controls. The results suggest that the PC2-derived peptides may play a functional role in morphine-induced antinociception, tolerance and dependence. Alternatively, lack of opioid peptides led to up-regulation of the MOP and altered morphine

  17. Mechanisms of Functional Hypoconnectivity in the Medial Prefrontal Cortex of Mecp2 Null Mice.

    PubMed

    Sceniak, Michael P; Lang, Min; Enomoto, Addison C; James Howell, C; Hermes, Douglas J; Katz, David M

    2016-05-01

    Frontal cortical dysfunction is thought to contribute to cognitive and behavioral features of autism spectrum disorders; however, underlying mechanisms are poorly understood. The present study sought to define how loss ofMecp2, the gene mutated in Rett syndrome (RTT), disrupts function in the murine medial prefrontal cortex (mPFC) using acute brain slices and behavioral testing. Compared with wildtype, pyramidal neurons in theMecp2null mPFC exhibit significant reductions in excitatory postsynaptic currents, the duration of excitatory UP-states, evoked population activity, and the ratio of NMDA:AMPA currents, as well as an increase in the relative fraction of NR2B currents. These functional changes are associated with reductions in the density of excitatory dendritic spines, the ratio of vesicular glutamate to GABA transporters and GluN1 expression. In contrast to recent reports on circuit defects in other brain regions, we observed no effect ofMecp2loss on inhibitory synaptic currents or expression of the inhibitory marker parvalbumin. Consistent with mPFC hypofunction,Mecp2nulls exhibit respiratory dysregulation in response to behavioral arousal. Our data highlight functional hypoconnectivity in the mPFC as a potential substrate for behavioral disruption in RTT and other disorders associated with reduced expression ofMecp2in frontal cortical regions. PMID:25662825

  18. Kharon1 Null Mutants of Leishmania mexicana Are Avirulent in Mice and Exhibit a Cytokinesis Defect within Macrophages

    PubMed Central

    Sanchez, Marco A.; Valli, Jessica; Gluenz, Eva; Landfear, Scott M.

    2015-01-01

    In a variety of eukaryotes, flagella play important roles both in motility and as sensory organelles that monitor the extracellular environment. In the parasitic protozoan Leishmania mexicana, one glucose transporter isoform, LmxGT1, is targeted selectively to the flagellar membrane where it appears to play a role in glucose sensing. Trafficking of LmxGT1 to the flagellar membrane is dependent upon interaction with the KHARON1 protein that is located at the base of the flagellar axoneme. Remarkably, while Δkharon1 null mutants are viable as insect stage promastigotes, they are unable to survive as amastigotes inside host macrophages. Although Δkharon1 promastigotes enter macrophages and transform into amastigotes, these intracellular parasites are unable to execute cytokinesis and form multinucleate cells before dying. Notably, extracellular axenic amastigotes of Δkharon1 mutants replicate and divide normally, indicating a defect in the mutants that is only exhibited in the intra-macrophage environment. Although the flagella of Δkharon1 amastigotes adhere to the phagolysomal membrane of host macrophages, the morphology of the mutant flagella is often distorted. Additionally, these null mutants are completely avirulent following injection into BALB/c mice, underscoring the critical role of the KHARON1 protein for viability of intracellular amastigotes and disease in the animal model of leishmaniasis. PMID:26266938

  19. Microglia contribute to circuit defects in Mecp2 null mice independent of microglia-specific loss of Mecp2 expression

    PubMed Central

    Schafer, Dorothy P; Heller, Christopher T; Gunner, Georgia; Heller, Molly; Gordon, Christopher; Hammond, Timothy; Wolf, Yochai; Jung, Steffen; Stevens, Beth

    2016-01-01

    Microglia, the resident CNS macrophages, have been implicated in the pathogenesis of Rett Syndrome (RTT), an X-linked neurodevelopmental disorder. However, the mechanism by which microglia contribute to the disorder is unclear and recent data suggest that microglia do not play a causative role. Here, we use the retinogeniculate system to determine if and how microglia contribute to pathogenesis in a RTT mouse model, the Mecp2 null mouse (Mecp2tm1.1Bird/y). We demonstrate that microglia contribute to pathogenesis by excessively engulfing, thereby eliminating, presynaptic inputs at end stages of disease (≥P56 Mecp2 null mice) concomitant with synapse loss. Furthermore, loss or gain of Mecp2 expression specifically in microglia (Cx3cr1CreER;Mecp2fl/yor Cx3cr1CreER; Mecp2LSL/y) had little effect on excessive engulfment, synapse loss, or phenotypic abnormalities. Taken together, our data suggest that microglia contribute to end stages of disease by dismantling neural circuits rendered vulnerable by loss of Mecp2 in other CNS cell types. DOI: http://dx.doi.org/10.7554/eLife.15224.001 PMID:27458802

  20. Microglia contribute to circuit defects in Mecp2 null mice independent of microglia-specific loss of Mecp2 expression.

    PubMed

    Schafer, Dorothy P; Heller, Christopher T; Gunner, Georgia; Heller, Molly; Gordon, Christopher; Hammond, Timothy; Wolf, Yochai; Jung, Steffen; Stevens, Beth

    2016-01-01

    Microglia, the resident CNS macrophages, have been implicated in the pathogenesis of Rett Syndrome (RTT), an X-linked neurodevelopmental disorder. However, the mechanism by which microglia contribute to the disorder is unclear and recent data suggest that microglia do not play a causative role. Here, we use the retinogeniculate system to determine if and how microglia contribute to pathogenesis in a RTT mouse model, the Mecp2 null mouse (Mecp2(tm1.1Bird/y)). We demonstrate that microglia contribute to pathogenesis by excessively engulfing, thereby eliminating, presynaptic inputs at end stages of disease (≥P56 Mecp2 null mice) concomitant with synapse loss. Furthermore, loss or gain of Mecp2 expression specifically in microglia (Cx3cr1(CreER);Mecp2(fl/y)or Cx3cr1(Cr)(eER); Mecp2(LSL/y)) had little effect on excessive engulfment, synapse loss, or phenotypic abnormalities. Taken together, our data suggest that microglia contribute to end stages of disease by dismantling neural circuits rendered vulnerable by loss of Mecp2 in other CNS cell types. PMID:27458802

  1. CMP-Neu5Ac Hydroxylase Null Mice as a Model for Studying Metabolic Disorders Caused by the Evolutionary Loss of Neu5Gc in Humans

    PubMed Central

    Kwon, Deug-Nam; Choi, Yun-Jung; Cho, Ssang-Goo; Park, Chankyu; Seo, Han Geuk; Song, Hyuk; Kim, Jin-Hoi

    2015-01-01

    The purpose of this study was to identify the modification/turnover of gene products that are altered in humans due to evolutionary loss of Neu5Gc. CMP-Neu5Ac hydroxylase- (Cmah-) deficient mice show the infiltration of Kupffer cells within liver sinusoids, whereas body and liver weight develop normally. Pathway analysis by use of Illumina MouseRef-8 v2 Expression BeadChip provided evidence that a number of biological pathways, including the glycolysis, gluconeogenesis, TCA cycle, and pentose phosphate pathways, as well as glycogen metabolism-related gene expression, were significantly upregulated in Cmah-null mice. The intracellular glucose supply in Cmah-null mice resulted in mitochondrial dysfunction, oxidative stress, and the advanced glycation end products accumulation that could further induce oxidative stress. Finally, low sirtuin-1 and sirtuin-3 gene expressions due to higher NADH/NAD in Cmah-null mice decreased Foxo-1 and MnSOD gene expression, suggesting that oxidative stress may result in mitochondrial dysfunction in Cmah-null mouse. The present study suggests that mice with CMAH deficiency can be taken as an important model for studying metabolic disorders in humans. PMID:26558285

  2. Neil2-null Mice Accumulate Oxidized DNA Bases in the Transcriptionally Active Sequences of the Genome and Are Susceptible to Innate Inflammation.

    PubMed

    Chakraborty, Anirban; Wakamiya, Maki; Venkova-Canova, Tatiana; Pandita, Raj K; Aguilera-Aguirre, Leopoldo; Sarker, Altaf H; Singh, Dharmendra Kumar; Hosoki, Koa; Wood, Thomas G; Sharma, Gulshan; Cardenas, Victor; Sarkar, Partha S; Sur, Sanjiv; Pandita, Tej K; Boldogh, Istvan; Hazra, Tapas K

    2015-10-01

    Why mammalian cells possess multiple DNA glycosylases (DGs) with overlapping substrate ranges for repairing oxidatively damaged bases via the base excision repair (BER) pathway is a long-standing question. To determine the biological role of these DGs, null animal models have been generated. Here, we report the generation and characterization of mice lacking Neil2 (Nei-like 2). As in mice deficient in each of the other four oxidized base-specific DGs (OGG1, NTH1, NEIL1, and NEIL3), Neil2-null mice show no overt phenotype. However, middle-aged to old Neil2-null mice show the accumulation of oxidative genomic damage, mostly in the transcribed regions. Immuno-pulldown analysis from wild-type (WT) mouse tissue showed the association of NEIL2 with RNA polymerase II, along with Cockayne syndrome group B protein, TFIIH, and other BER proteins. Chromatin immunoprecipitation analysis from mouse tissue showed co-occupancy of NEIL2 and RNA polymerase II only on the transcribed genes, consistent with our earlier in vitro findings on NEIL2's role in transcription-coupled BER. This study provides the first in vivo evidence of genomic region-specific repair in mammals. Furthermore, telomere loss and genomic instability were observed at a higher frequency in embryonic fibroblasts from Neil2-null mice than from the WT. Moreover, Neil2-null mice are much more responsive to inflammatory agents than WT mice. Taken together, our results underscore the importance of NEIL2 in protecting mammals from the development of various pathologies that are linked to genomic instability and/or inflammation. NEIL2 is thus likely to play an important role in long term genomic maintenance, particularly in long-lived mammals such as humans. PMID:26245904

  3. Phenotypes Developed in Secretin Receptor-Null Mice Indicated a Role for Secretin in Regulating Renal Water Reabsorption▿

    PubMed Central

    Chu, Jessica Y. S.; Chung, Samuel C. K.; Lam, Amy K. M.; Tam, Sidney; Chung, Sookja K.; Chow, Billy K. C.

    2007-01-01

    Aquaporin 2 (AQP2) is responsible for regulating the concentration of urine in the collecting tubules of the kidney under the control of vasopressin (Vp). Studies using Vp-deficient Brattleboro rats, however, indicated the existence of substantial Vp-independent mechanisms for membrane insertion, as well as transcriptional regulation, of this water channel. The Vp-independent mechanism(s) is clinically relevant to patients with X-linked nephrogenic diabetes insipidus (NDI) by therapeutically bypassing the dysfunctional Vp receptor. On the basis of studies with secretin receptor-null (SCTR−/−) mice, we report here for the first time that mutation of the SCTR gene could lead to mild polydipsia and polyuria. Additionally, SCTR−/− mice were shown to have reduced renal expression of AQP2 and AQP4, as well as altered glomerular and tubular morphology, suggesting possible disturbances in the filtration and/or water reabsorption process in these animals. By using SCTR−/− mice as controls and comparing them with wild-type animals, we performed both in vivo and in vitro studies that demonstrated a role for secretin in stimulating (i) AQP2 translocation from intracellular vesicles to the plasma membrane in renal medullary tubules and (ii) expression of this water channel under hyperosmotic conditions. The present study therefore provides information for at least one of the Vp-independent mechanisms that modulate the process of renal water reabsorption. Future investigations in this direction should be important in developing therapeutic means for treating NDI patients. PMID:17283064

  4. 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

  5. Altered Body Weight Regulation in CK1ε Null and tau Mutant Mice on Regular Chow and High Fat Diets

    PubMed Central

    Zhou, Lili; Summa, Keith C.; Olker, Christopher; Vitaterna, Martha H.; Turek, Fred W.

    2016-01-01

    Disruption of circadian rhythms results in metabolic dysfunction. Casein kinase 1 epsilon (CK1ε) is a canonical circadian clock gene. Null and tau mutations in CK1ε show distinct effects on circadian period. To investigate the role of CK1ε in body weight regulation under both regular chow (RC) and high fat (HF) diet conditions, we examined body weight on both RC and HF diets in CK1ε−/− and CK1εtau/tau mice on a standard 24 hr light-dark (LD) cycle. Given the abnormal entrainment of CK1εtau/tau mice on a 24 hr LD cycle, a separate set of CK1εtau/tau mice were tested under both diet conditions on a 20 hr LD cycle, which more closely matches their endogenous period length. On the RC diet, both CK1ε−/− and CK1εtau/tau mutants on a 24 hr LD cycle and CK1εtau/tau mice on a 20 hr LD cycle exhibited significantly lower body weights, despite similar overall food intake and activity levels. On the HF diet, CK1εtau/tau mice on a 20 hr LD cycle were protected against the development of HF diet-induced excess weight gain. These results provide additional evidence supporting a link between circadian rhythms and energy regulation at the genetic level, particularly highlighting CK1ε involved in the integration of circadian biology and metabolic physiology. PMID:27144030

  6. Leptin Resistance Contributes to Obesity in Mice with Null Mutation of Carcinoembryonic Antigen-related Cell Adhesion Molecule 1.

    PubMed

    Heinrich, Garrett; Russo, Lucia; Castaneda, Tamara R; Pfeiffer, Verena; Ghadieh, Hilda E; Ghanem, Simona S; Wu, Jieshen; Faulkner, Latrice D; Ergün, Süleyman; McInerney, Marcia F; Hill, Jennifer W; Najjar, Sonia M

    2016-05-20

    Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) promotes hepatic insulin clearance. Consistently, mice with null mutation of Ceacam1 (Cc1(-/-)) exhibit impaired insulin clearance with increased lipid production in liver and redistribution to white adipose tissue, leading to visceral obesity at 2 months of age. When the mutation is propagated on the C57/BL6J genetic background, total fat mass rises significantly with age, and glucose intolerance and systemic insulin resistance develop at 6 months of age. This study was carried out to determine the mechanisms underlying the marked increase in total fat mass in 6-month-old mutants. Indirect calorimetry analysis showed that Cc1(-/-) mice develop hyperphagia and a significant reduction in physical activity, in particular in the early hours of the dark cycle, during which energy expenditure is only slightly lower than in wild-type mice. They also exhibit increased triglyceride accumulation in skeletal muscle, due in part to incomplete fatty acid β-oxidation. Mechanistically, hypothalamic leptin signaling is reduced, as demonstrated by blunted STAT3 phosphorylation in coronal sections in response to an intracerebral ventricular injection of leptin. Hypothalamic fatty-acid synthase activity is also elevated in the mutants. Together, the data show that the increase in total fat mass in Cc1(-/-) mice is mainly attributed to hyperphagia and reduced spontaneous physical activity. Although the contribution of the loss of CEACAM1 from anorexigenic proopiomelanocortin neurons in the arcuate nucleus is unclear, leptin resistance and elevated hypothalamic fatty-acid synthase activity could underlie altered energy balance in these mice. PMID:27002145

  7. Oxidative stress and ROS metabolism via down-regulation of sirtuin 3 expression in Cmah-null mice affect hearing loss

    PubMed Central

    Choi, Yun-Jung; Gurunathan, Sangiliyandi; Kim, Jin-Hoi

    2015-01-01

    CMP-Neu5Ac hydroxylase (Cmah) disruption caused several abnormalities and diseases including hearing loss in old age. However, underling molecular mechanisms that give rise to age-related hearing loss (AHL) in Cmah-null mouse are still obscure. In this study, Cmah-null mice showed age-related decline of hearing associated with loss of sensory hair cells, spiral ganglion neurons, and/or stria vascularis degeneration in the cochlea. To identify differential gene expression profiles and pathway associated with AHL, we performed microarray analysis using Illumina MouseRef-8 v2 Expression BeadChip and pathway-focused PCR array in the cochlear tissues of Cmah-null mouse. Pathway and molecular mechanism analysis using differentially expressed genes provided evidences that altered biological pathway due to oxidative damage by low expressed antioxidants and dysregulated reactive oxygen species (ROS) metabolism. Especially, low sirtuin 3 (Sirt3) gene expressions in Cmah-null mice decreased both of downstream regulator (Foxo1 and MnSod) and regulatory transcription factor (Hif1α and Foxo3a) gene expression. Taken together, we suggest that down-regulation of Sirt3 expression leads to oxidative stress and mitochondrial dysfunction by regulation of ROS and that it could alter various signaling pathways in Cmah-null mice with AHL. PMID:26319214

  8. Spontaneous hypertension occurs with adipose tissue dysfunction in perilipin-1 null mice.

    PubMed

    Zou, Liangqiang; Wang, Weiyi; Liu, Shangxin; Zhao, Xiaojing; Lyv, Ying; Du, Congkuo; Su, Xueying; Geng, Bin; Xu, Guoheng

    2016-02-01

    Perilipin-1 (Plin1) coats lipid droplets exclusively in adipocytes and regulates two principle functions of adipose tissue, triglyceride storage and hydrolysis, which are disrupted upon Plin1 deficiency. In the present study, we investigated the alterations in systemic metabolites and hormones, vascular function and adipose function in spontaneous hypertensive mice lacking perilipin-1 (Plin1-/-). Plin1-/- mice developed spontaneous hypertension without obvious alterations in systemic metabolites and hormones. Plin1 expressed only in adipose cells but not in vascular cells, so its ablation would have no direct effect in situ on blood vessels. Instead, Plin1-/- mice showed dysfunctions of perivascular adipose tissue (PVAT), a fat depot that anatomically surrounds systemic arteries and has an anticontractile effect. In Plin1-/- mice, aortic and mesenteric PVAT were reduced in mass and adipocyte derived relaxing factor secretion, but increased in basal lipolysis, angiotensin II secretion, macrophage infiltration and oxidative stress. Such multiple culprits impaired the anticontractile effect of PVAT to promote vasoconstriction of aortic and mesenteric arteries of Plin1-/- mice. Furthermore, arterial vessels of Plin1-/- mice showed increasing angiotensin II receptor type 1, monocyte chemotactic protein-1 and interlukin-6 expression, structural damage of endothelial and smooth muscle cells, along with impaired endothelium-dependent relaxation. Hypertension in Plin1-/- mice might occur as a deleterious consequence of PVAT dysfunction. This finding provides the direct evidence that links dysfunctional PVAT to vascular dysfunction and hypertension, particularly in pathophysiological states. This hypertensive mouse model might mimic and explain the hypertension occurring in patients with adipose tissue dysfunction, particularly with Plin1 mutations. PMID:26521150

  9. GPRC6A Null Mice Exhibit Osteopenia, Feminization and Metabolic Syndrome

    PubMed Central

    Pi, Min; Chen, Ling; Huang, Min-Zhao; Zhu, Wenyu; Ringhofer, Brian; Luo, Junming; Christenson, Lane; Li, Benyi; Zhang, Jianghong; Jackson, P. David; Faber, Pieter; Brunden, Kurt R.; Harrington, John J.; Quarles, L. Darryl

    2008-01-01

    Background GPRC6A is a widely expressed orphan G-protein coupled receptor that senses extracellular amino acids, osteocalcin and divalent cations in vitro. The physiological functions of GPRC6A are unknown. Methods/Principal Findings In this study, we created and characterized the phenotype of GPRC6A−/− mice. We observed complex metabolic abnormalities in GPRC6A−/− mice involving multiple organ systems that express GPRC6A, including bone, kidney, testes, and liver. GPRC6A−/− mice exhibited hepatic steatosis, hyperglycemia, glucose intolerance, and insulin resistance. In addition, we observed high expression of GPRC6A in Leydig cells in the testis. Ablation of GPRC6A resulted in feminization of male GPRC6A−/− mice in association with decreased lean body mass, increased fat mass, increased circulating levels of estradiol, and reduced levels of testosterone. GPRC6A was also highly expressed in kidney proximal and distal tubules, and GPRC6A−/− mice exhibited increments in urine Ca/Cr and PO4/Cr ratios as well as low molecular weight proteinuria. Finally, GPRC6A−/− mice exhibited a decrease in bone mineral density (BMD) in association with impaired mineralization of bone. Conclusions/Significance GPRC6A−/− mice have a metabolic syndrome characterized by defective osteoblast-mediated bone mineralization, abnormal renal handling of calcium and phosphorus, fatty liver, glucose intolerance and disordered steroidogenesis. These findings suggest the overall function of GPRC6A may be to coordinate the anabolic responses of multiple tissues through the sensing of extracellular amino acids, osteocalcin and divalent cations. PMID:19050760

  10. Hepatobiliary cholesterol transport is not impaired in Abca1-null mice lacking HDL

    PubMed Central

    Groen, Albert K.; Bloks, Vincent W.; Bandsma, Robert H.J.; Ottenhoff, Roelof; Chimini, Giovanna; Kuipers, Folkert

    2001-01-01

    The ABC transporter ABCA1 regulates HDL levels and is considered to control the first step of reverse cholesterol transport from the periphery to the liver. To test this concept, we studied the effect of ABCA1 deficiency on hepatic metabolism and hepatobiliary flux of cholesterol in mice. Hepatic lipid contents and biliary secretion rates were determined in Abca1–/–, Abca1+/–, and Abca1+/+ mice with a DBA background that were fed either standard chow or a high-fat, high-cholesterol diet. Hepatic cholesterol and phospholipid contents in Abca1–/– mice were indistinguishable from those in Abca1+/– and Abca1+/+ mice on both diets. In spite of the absence of HDL, biliary secretion rates of cholesterol, bile salts, and phospholipid were unimpaired in Abca1–/– mice. Neither the hepatic expression levels of genes controlling key steps in cholesterol metabolism nor the contribution of de novo synthesis to biliary cholesterol and bile salts were affected by Abca genotype. Finally, fecal excretion of neutral and acidic sterols was similar in all groups. We conclude that plasma HDL levels and ABCA1 activity do not control net cholesterol transport from the periphery via the liver into the bile, indicating that the importance of HDL in reverse cholesterol transport requires re-evaluation. PMID:11560953

  11. Park2-null/tau transgenic mice reveal a functional relationship between parkin and tau.

    PubMed

    Guerrero, Rosa; Navarro, Paloma; Gallego, Eva; Avila, Jesus; de Yebenes, Justo G; Sanchez, Marina P

    2008-03-01

    Mutations, haplotypes, and polymorphisms of tau and Park-2 genes constitute risk factors for developing tauopathies. In order to analyze the possible relationship between parkin and tau we generated a double-mutant mouse deficient for Park-2 expression and overexpressing a mutant tau protein (hTauVLW). Mice develop normally, although the median survival rate is considerably reduced with respect to wild type (45%). Aggregates of phosphorylated tau in neurons and reactive gliosis are quite abundant in cortex and hippocampus of these mice. Moreover, while in young transgenic mice the hTauVLW immunostained transgene product is observed in both cell bodies and dendrites, the hTauVLW mutant protein is only detected in the neuronal cell bodies when Park-2 gene is additionally deleted. Moreover, DNA fragmentation was detected by the TUNEL method, and cerebral atrophy is also present in these regions. The levels of phosphorylated tau and Hsp70 are increased in the double-mutant mice, while CHIP expression in hippocampus is lower when the Park-2 gene is deleted. Thus, the combination of Park-2 gene deletion with hTauVLW transgene overexpression in mice produces serious neuropathological effects, which reflect the existence of some relationship between both proteins. PMID:18376058

  12. Characterizing the role of endothelin-1 in the progression of cardiac hypertrophy in aryl hydrocarbon receptor (AhR) null mice

    SciTech Connect

    Lund, Amie K.; Goens, M. Beth; Nunez, Bethany A.; Walker, Mary K. . E-mail: mkwalker@unm.edu

    2006-04-15

    The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor characterized to play a role in detection and adaptation to environmental stimuli. Genetic deletion of AhR results in hypertension, and cardiac hypertrophy and fibrosis, associated with elevated plasma angiotensin II (Ang II) and endothelin-1 (ET-1), thus AhR appears to contribute to cardiovascular homeostasis. In these studies, we tested the hypothesis that ET-1 mediates cardiovascular pathology in AhR null mice via ET{sub A} receptor activation. First, we determine the time courses of cardiac hypertrophy, and of plasma and tissue ET-1 expression in AhR wildtype and null mice. AhR null mice exhibited increases in heart-to-body weight ratio and age-related expression of cardiac hypertrophy markers, {beta}-myosin heavy chain ({beta}-MHC), and atrial natriuretic factor (ANF), which were significant at 2 months. Similarly, plasma and tissue ET-1 expression was significantly elevated at 2 months and increased further with age. Second, AhR null mice were treated with ET{sub A} receptor antagonist, BQ-123 (100 nmol/kg/day), for 7, 28, or 58 days and blood pressure, cardiac fibrosis, and cardiac hypertrophy assessed, respectively. BQ-123 for 7 days significantly reduced mean arterial pressure in conscious, catheterized mice. BQ-123 for 28 days significantly reduced the histological appearance of cardiac fibrosis. Treatment for 58 days significantly reduced cardiac mass, assessed by heart weight, echocardiography, and {beta}-MHC and ANF expression; and reduced cardiac fibrosis as determined by osteopontin and collagen I mRNA expression. These findings establish ET-1 and the ET{sub A} receptor as primary determinants of hypertension and cardiac pathology in AhR null mice.

  13. Ciliary neurotrophic factor is not required for terminal sprouting and compensatory reinnervation of neuromuscular synapses: Re-evaluation of CNTF null mice

    PubMed Central

    Wright, Megan C.; Son, Young-Jin

    2007-01-01

    Loss of synaptic activity or innervation induces sprouting of intact motor nerve terminals that adds or restores nerve-muscle connectivity. Ciliary neurotrophic factor (CNTF) and terminal Schwann cells (tSCs) have been implicated as molecular and cellular mediators of the compensatory process. We wondered if the previously reported lack of terminal sprouting in CNTF null mice was due to abnormal reactivity of tSCs. To this end, we examined nerve terminal and tSC responses in CNTF null mice using experimental systems that elicited extensive sprouting in wildtype mice. Contrary to the previous report, we found that motor nerve terminals in the null mice sprout extensively in response to major sprouting-stimuli such as exogenously applied CNTF per se, botulinum toxin-elicited paralysis, and partial denervation by L4 spinal root transection. In addition, the number, length and growth patterns of terminal sprouts, and the extent of reinnervation by terminal or nodal sprouts, were similar in wildtype and null mice. tSCs in the null mice were also reactive to the sprouting-stimuli, elaborating cellular processes that accompanied terminal sprouts or guided reinnervation of denervated muscle fibers. Lastly, CNTF was absent in quiescent tSCs in intact, wildtype muscles and little if any was detected in reactive tSCs in denervated muscles. Thus, CNTF is not required for induction of nerve terminal sprouting, for reactivation of tSCs, and for compensatory reinnervation after nerve injury. We interpret these results to support the notion that compensatory sprouting in adult muscles is induced primarily by contact-mediated mechanisms, rather than by diffusible factors. PMID:17445802

  14. Restoration of the serum level of SERPINF1 does not correct the bone phenotype in Serpinf1 null mice.

    PubMed

    Rajagopal, Abbhirami; Homan, Erica P; Joeng, Kyu Sang; Suzuki, Masataka; Bertin, Terry; Cela, Racel; Munivez, Elda; Dawson, Brian; Jiang, Ming-Ming; Gannon, Frank; Crawford, Susan; Lee, Brendan H

    2016-03-01

    Osteogenesis imperfecta (OI) is a group of genetic disorders characterized by bone fragility and deformity. OI type VI is unique owing to the mineralization defects observed in patient biopsies. Furthermore, it has been reported to respond less well to standard therapy with bisphosphonates [1]. Others and we have previously identified SERPINF1 mutations in patients with OI type VI. SERPINF1 encodes pigment epithelium derived factor (PEDF), a secreted collagen-binding glycoprotein that is absent in the sera of patients with OI type VI. Serpinf1 null mice show increased osteoid and decreased bone mass, and thus recapitulate the OI type VI phenotype. We tested whether restoration of circulating PEDF in the blood could correct the phenotype of OI type VI in the context of protein replacement. To do so, we utilized a helper-dependent adenoviral vector (HDAd) to express human SERPINF1 in the mouse liver and assessed whether PEDF secreted from the liver was able to rescue the bone phenotype observed in Serpinf1(-/-) mice. We confirmed that expression of SERPINF1 in the liver restored the serum level of PEDF. We also demonstrated that PEDF secreted from the liver was biologically active by showing the expected metabolic effects of increased adiposity and impaired glucose tolerance in Serpinf1(-/-) mice. Interestingly, overexpression of PEDF in vitro increased mineralization with a concomitant increase in the expression of bone gamma-carboxyglutamate protein, alkaline phosphatase and collagen, type I, alpha I, but the increased serum PEDF level did not improve the bone phenotype of Serpinf1(-/-) mice. These results suggest that PEDF may function in a context-dependent and paracrine fashion in bone homeostasis. PMID:26693895

  15. Soluble maltase-glucoamylase is alternatively spliced and secreted by Paneth and goblet cells in enterocyte maltase-glucoamylase Null mice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Starch is the major energy source in the mouse diet. Knockout of intestinal membrane-bound maltase-glucoamylase (Mgam) in mice revealed presence of soluble starch digesting activity in Null jejunum and ileum that is secreted by Paneth and goblet cells. Hypotheses: 1. WT have two Mgam mRNAs, Mgamme...

  16. GENE PROFILING IN WILD TYPE AND PPARÁ NULL MICE EXPOSED TO PFOA

    EPA Science Inventory

    Perflurooctanoic acid (PFOA) is a perfluoroalkyl acid used in a variety of commercial applications. Concerns have been raised because PFOA is ubiquitous in the environment and can be detected in human tissues. PFOA is a rodent carcinogen and a developmental toxicant in mice. W...

  17. Enhanced Susceptibility of Ago1/3 Double-Null Mice to Influenza A Virus Infection

    PubMed Central

    Van Stry, Melanie; Oguin, Thomas H.; Cheloufi, Sihem; Vogel, Peter; Watanabe, Makiko; Pillai, Meenu R.; Dash, Pradyot; Thomas, Paul G.; Hannon, Gregory J.

    2012-01-01

    RNA interference (RNAi) is a critical component of many cellular antiviral responses in plants, invertebrates, and mammals. However, its in vivo role in host protection from the negative-sense RNA virus influenza virus type A (flu) is unclear. Here we have examined the role of RNAi in host defense to flu by analyzing Argonaute 1 and 3 double-knockout mice deficient in components of the RNA-induced silencing complex. Compared to littermate controls, flu-infected double-knockout mice exhibited increased mortality, consistent with more severe alveolitis and pneumonitis. These data indicate that optimal resistance to flu requires Argonaute 1 and/or 3. Enhanced mortality of double-knockout mice was not associated either with increased viral replication or with differential pulmonary recruitment or function of innate and adaptive immune cells. Given the absence of detectable immune defects, our results support the notion that the enhanced flu susceptibility of double-knockout mice arises from an intrinsic impairment in the ability of lung cells to tolerate flu-elicited inflammation. PMID:22318144

  18. Enhanced susceptibility of Ago1/3 double-null mice to influenza A virus infection.

    PubMed

    Van Stry, Melanie; Oguin, Thomas H; Cheloufi, Sihem; Vogel, Peter; Watanabe, Makiko; Pillai, Meenu R; Dash, Pradyot; Thomas, Paul G; Hannon, Gregory J; Bix, Mark

    2012-04-01

    RNA interference (RNAi) is a critical component of many cellular antiviral responses in plants, invertebrates, and mammals. However, its in vivo role in host protection from the negative-sense RNA virus influenza virus type A (flu) is unclear. Here we have examined the role of RNAi in host defense to flu by analyzing Argonaute 1 and 3 double-knockout mice deficient in components of the RNA-induced silencing complex. Compared to littermate controls, flu-infected double-knockout mice exhibited increased mortality, consistent with more severe alveolitis and pneumonitis. These data indicate that optimal resistance to flu requires Argonaute 1 and/or 3. Enhanced mortality of double-knockout mice was not associated either with increased viral replication or with differential pulmonary recruitment or function of innate and adaptive immune cells. Given the absence of detectable immune defects, our results support the notion that the enhanced flu susceptibility of double-knockout mice arises from an intrinsic impairment in the ability of lung cells to tolerate flu-elicited inflammation. PMID:22318144

  19. LPS-induced systemic inflammation is more severe in P2Y12 null mice.

    PubMed

    Liverani, Elisabetta; Rico, Mario C; Yaratha, Laxmikausthubha; Tsygankov, Alexander Y; Kilpatrick, Laurie E; Kunapuli, Satya P

    2014-02-01

    Thienopyridines are a class of antiplatelet drugs that are metabolized in the liver to several metabolites, of which only one active metabolite can irreversibly antagonize the platelet P2Y12 receptor. Possible effects of these drugs and the role of activated platelets in inflammatory responses have also been investigated in a variety of animal models, demonstrating that thienopyridines could alter inflammation. However, it is not clear whether it is caused only by the P2Y12 antagonism or whether off-target effects of other metabolites also intervene. To address this question, we investigated P2Y12 KO mice during a LPS-induced model of systemic inflammation, and we treated these KO mice with a thienopyridine drug (clopidogrel). Contrary to the reported effects of clopidogrel, numbers of circulating WBCs and plasma levels of cytokines were increased in LPS-exposed KO mice compared with WT in this inflammation model. Moreover, both spleen and bone marrow show an increase in cell content, suggesting a role for P2Y12 in regulation of bone marrow and spleen cellular composition. Finally, the injury was more severe in the lungs of KO mice compared with WT. Interestingly, clopidogrel treatments also exerted protective effects in KO mice, suggesting off-target effects for this drug. In conclusion, the P2Y12 receptor plays an important role during LPS-induced inflammation, and this signaling pathway may be involved in regulating cell content in spleen and bone marrow during LPS systemic inflammation. Furthermore, clopidogrel may have effects that are independent of P2Y12 receptor blockade. PMID:24142066

  20. Impaired neutrophil function in 24p3 null mice contributes to enhanced susceptibility to bacterial infections

    PubMed Central

    Liu, Zhuoming; Petersen, Robert; Devireddy, L.

    2013-01-01

    Lipocalin 24p3 (24p3) is a neutrophil secondary granule protein. 24p3 is also a siderocalin, which binds several bacterial siderophores. It was therefore proposed that synthesis and secretion of 24p3 by stimulated macrophages or release of 24p3 upon neutrophil degranulation sequesters iron-laden siderophores to attenuate bacterial growth. Accordingly, 24p3-deficient mice are susceptible to bacterial pathogens whose siderophores would normally be chelated by 24p3. Specific granule deficiency (SGD) is a rare congenital disorder characterized by complete absence of proteins in secondary granules. Neutrophils from SGD patients, who are prone to bacterial infections, lack normal functions but the potential role of 24p3 in neutrophil dysfunction in SGD is not known. Here we show that neutrophils from 24p3−/− mice are defective in many neutrophil functions. Specifically, neutrophils in 24p3−/− mice do not extravasate to sites of infection and are defective for chemotaxis. A transcriptome analysis revealed that genes that control cytoskeletal reorganization are selectively suppressed in 24p3−/− neutrophils. Additionally, small regulatory RNAs (miRNAs) that control upstream regulators of cytoskeletal proteins are also increased in 24p3−/− neutrophils. Further, 24p3−/− neutrophils failed to phagocytose bacteria, which may account for the enhanced sensitivity of 24p3−/− mice to both intracellular (Listeria monocytogenes) and extracellular (Candida albicans, Staphylococcus aureus) pathogens. Listeria does not secrete siderophores and additionally, the siderophore secreted by Candida is not sequestered by 24p3. Therefore, the heightened sensitivity of 24p3−/− mice to these pathogens is not due to sequestration of siderophores limiting iron availability, but is a consequence of impaired neutrophil function. PMID:23543755

  1. Ectopic cerebellar cell migration causes maldevelopment of Purkinje cells and abnormal motor behaviour in Cxcr4 null mice.

    PubMed

    Huang, Guo-Jen; Edwards, Andrew; Tsai, Cheng-Yu; Lee, Yi-Shin; Peng, Lei; Era, Takumi; Hirabayashi, Yoshio; Tsai, Ching-Yen; Nishikawa, Shin-Ichi; Iwakura, Yoichiro; Chen, Shu-Jen; Flint, Jonathan

    2014-01-01

    SDF-1/CXCR4 signalling plays an important role in neuronal cell migration and brain development. However, the impact of CXCR4 deficiency in the postnatal mouse brain is still poorly understood. Here, we demonstrate the importance of CXCR4 on cerebellar development and motor behaviour by conditional inactivation of Cxcr4 in the central nervous system. We found CXCR4 plays a key role in cerebellar development. Its loss leads to defects in Purkinje cell dentritogenesis and axonal projection in vivo but not in cell culture. Transcriptome analysis revealed the most significantly affected pathways in the Cxcr4 deficient developing cerebellum are involved in extra cellular matrix receptor interactions and focal adhesion. Consistent with functional impairment of the cerebellum, Cxcr4 knockout mice have poor coordination and balance performance in skilled motor tests. Together, these results suggest ectopic the migration of granule cells impairs development of Purkinje cells, causes gross cerebellar anatomical disruption and leads to behavioural motor defects in Cxcr4 null mice. PMID:24516532

  2. Comparative metabolism of methacrylonitrile and acrylonitrile to cyanide using cytochrome P4502E1 and microsomal epoxide hydrolase-null mice

    SciTech Connect

    El Hadri, L.; Chanas, B.; Ghanayem, B.I. . E-mail: ghanayem@niehs.nih.gov

    2005-06-01

    Methacrylonitrile (MAN) and acrylonitrile (AN) are metabolized via glutathione (GSH) conjugation or epoxide formation. We have recently shown that CYP2E1 is essential for AN epoxidation and subsequent cyanide liberation. Current studies were designed to compare the enzymatic basis of MAN vs. AN metabolism to cyanide using wild-type (WT), CYP2E1-, and mEH-null mice. Mice received a single gavage dose of 0.047, 0.095, 0.19, or 0.38 mmol/kg of MAN or AN, and blood cyanide was measured at 1 or 3 h later. Blood cyanide levels in WT mice treated with AN or MAN were dose and time dependent. At equimolar doses, significantly higher levels of cyanide were detected in the blood of MAN- vs. AN-treated mice. Further, while significant reduction in blood cyanide levels occurred in MAN-treated CYP2E1-null vs. WT mice, AN metabolism to cyanide was largely abolished in CYP2E1-null mice. Pretreatment of mice with 1-aminobenzotriazole (ABT, CYP inhibitor) demonstrated that CYPs other than CYP2E1 also contribute to MAN metabolism to cyanide. Blood cyanide levels in mEH-null mice treated with aliphatic nitriles are generally lower than levels in similarly treated WT mice. Western blot analysis showed that expression of sEH was greater in male vs. female mice. The role of various epoxide hydrolases (EHs) in the production of cyanide from aliphatic nitriles is apparently structure and dose dependent. Regardless of genotype, significantly higher levels of cyanide were measured in the blood of male vs. female mice treated with MAN or AN. In conclusion, these data showed that (1) at equimolar doses, higher blood cyanide levels were detected in mice treated with MAN vs. AN; (2) while CYP2E1 is the only enzyme responsible for AN metabolism to cyanide, other CYPs also contribute to MAN metabolism; and (3) significantly higher levels of cyanide were measured in the blood of male vs. female treated with either nitrile. Higher blood cyanide levels in male vs. female mice and in MAN- vs. AN

  3. Analysis of Trafficking, Stability and Function of Human Connexin 26 Gap Junction Channels with Deafness-Causing Mutations in the Fourth Transmembrane Helix

    PubMed Central

    Ambrosi, Cinzia; Walker, Amy E.; DePriest, Adam D.; Cone, Angela C.; Lu, Connie; Badger, John; Skerrett, I. Martha; Sosinsky, Gina E.

    2013-01-01

    Human Connexin26 gene mutations cause hearing loss. These hereditary mutations are the leading cause of childhood deafness worldwide. Mutations in gap junction proteins (connexins) can impair intercellular communication by eliminating protein synthesis, mis-trafficking, or inducing channels that fail to dock or have aberrant function. We previously identified a new class of mutants that form non-functional gap junction channels and hemichannels (connexons) by disrupting packing and inter-helix interactions. Here we analyzed fourteen point mutations in the fourth transmembrane helix of connexin26 (Cx26) that cause non-syndromic hearing loss. Eight mutations caused mis-trafficking (K188R, F191L, V198M, S199F, G200R, I203K, L205P, T208P). Of the remaining six that formed gap junctions in mammalian cells, M195T and A197S formed stable hemichannels after isolation with a baculovirus/Sf9 protein purification system, while C202F, I203T, L205V and N206S formed hemichannels with varying degrees of instability. The function of all six gap junction-forming mutants was further assessed through measurement of dye coupling in mammalian cells and junctional conductance in paired Xenopus oocytes. Dye coupling between cell pairs was reduced by varying degrees for all six mutants. In homotypic oocyte pairings, only A197S induced measurable conductance. In heterotypic pairings with wild-type Cx26, five of the six mutants formed functional gap junction channels, albeit with reduced efficiency. None of the mutants displayed significant alterations in sensitivity to transjunctional voltage or induced conductive hemichannels in single oocytes. Intra-hemichannel interactions between mutant and wild-type proteins were assessed in rescue experiments using baculovirus expression in Sf9 insect cells. Of the four unstable mutations (C202F, I203T, L205V, N206S) only C202F and N206S formed stable hemichannels when co-expressed with wild-type Cx26. Stable M195T hemichannels displayed an increased

  4. Cyclooxygenase-1 null mice show reduced neuroinflammation in response to β-amyloid

    PubMed Central

    Choi, Sang-Ho; Bosetti, Francesca

    2009-01-01

    Several independent epidemiological studies indicate that chronic use of non-steroidal anti-inflammatory drugs can reduce the risk of developing Alzheimer's disease (AD), supporting the inflammatory cascade hypothesis. Although the first clinical trial with indomethacin, a preferential cyclooxygenase (COX)-1 inhibitor, showed beneficial effects, subsequent large clinical trials, mostly using COX-2 inhibitors, failed to show any beneficial effect in AD patients with mild to severe cognitive impairment. These combined data suggest that either an early treatment is crucial to stop the mechanisms underlying the disease before the onset of the symptoms, or that preferential COX-1 inhibition, rather than COX-2, is beneficial. Therefore, a full understanding of the physiological, pathological, and/or neuroprotective role of COX isoforms may help to develop better therapeutic strategies for the prevention or treatment of AD. In this study, we examined the effect of COX-1 genetic deletion on the inflammatory response and neurodegeneration induced by β-amyloid. β-amyloid (Aβ1-42) was centrally injected in the lateral ventricle of COX-1-deficient (COX-1-/-) and their respective wild-type (WT) mice. In COX-1-/- mice, Aβ1-42-induced inflammatory response and neuronal damage were attenuated compared to WT mice, as shown by Fluoro-Jade B and nitrotyrosine staining. These results indicate that inhibition of COX-1 activity may be valid therapeutic strategy to reduce brain inflammatory response and neurodegeneration. PMID:20157512

  5. Attenuated Reactive Gliosis and Enhanced Functional Recovery Following Spinal Cord Injury in Null Mutant Mice of Platelet-Activating Factor Receptor.

    PubMed

    Wang, Yuanyi; Gao, Zhongwen; Zhang, Yiping; Feng, Shi-Qing; Liu, Yulong; Shields, Lisa B E; Zhao, Ying-Zheng; Zhu, Qingsan; Gozal, David; Shields, Christopher B; Cai, Jun

    2016-07-01

    Platelet-activating factor (PAF) is a unique phosphoglycerine that mediates the biological functions of both immune and nervous systems. Excessive PAF plays an important role in neural injury via its specific receptor (PAFR). In this study, we hypothesized that PAF signaling activates reactive gliosis after spinal cord injury (SCI), and blocking the PAF pathway would modify the glia scar formation and promote functional recovery. PAF microinjected into the normal wild-type spinal cord induced a dose-dependent activation of microglia and astrocytes. In the SCI mice, PAFR null mutant mice showed a better functional recovery in grip and rotarod performances than wild-type mice. Although both microglia and astrocytes were activated after SCI in wild-type and PAFR null mutant mice, expressions of IL-6, vimentin, nestin, and GFAP were not significantly elevated in PAFR null mutants. Disruption of PAF signaling inhibited the expressions of proteoglycan CS56 and neurocan (CSPG3). Intriguingly, compared to the wild-type SCI mice, less axonal retraction/dieback at 7 dpi but more NFH-labeled axons at 28 dpi was found in the area adjacent to the epicenter in PAFR null mutant SCI mice. Moreover, treatment with PAFR antagonist Ginkgolide B (GB) at the chronic phase rather than acute phase enhanced the functional recovery in the wild-type SCI mice. These findings suggest that PAF signaling participates in reactive gliosis after SCI, and blocking of this signaling enhances functional recovery and to some extent may promote axon regrowth. PMID:26084439

  6. Genetically null mice reveal a central role for epidermal growth factor receptor in the differentiation of the hair follicle and normal hair development.

    PubMed Central

    Hansen, L. A.; Alexander, N.; Hogan, M. E.; Sundberg, J. P.; Dlugosz, A.; Threadgill, D. W.; Magnuson, T.; Yuspa, S. H.

    1997-01-01

    Mice harboring a targeted disruption of the epidermal growth factor receptor (EGFR) allele exhibit a severely disorganized hair follicle phenotype, fuzzy coat, and systemic disease resulting in death before 3 weeks. This skin phenotype was reproduced in whole skin grafts and in grafts of EGFR null hair follicle buds onto nude mice, providing a model to evaluate the natural evolution of skin lacking the EGFR. Hair follicles in grafts of null skin did not progress from anagen to telogen and scanning electron micrografts revealed wavy, flattened hair fibers with cuticular abnormalities. Many of the EGFR null hair follicles in the grafted skin were consumed by an inflammatory reaction resulting in complete hair loss in 67% of the grafts by 10 weeks. Localization of follicular differentiation markers including keratin 6, transglutaminase, and the hair keratins mHa2 and hacl-1 revealed a pattern of premature differentiation within the null hair follicles. In intact EGFR null mice, proliferation in the interfollicular epidermis, but not hair follicles, was greatly decreased in the absence of EGFR. In contrast, grafting of EGFR null skin resulted in a hyperplastic response in the epidermis that did not resolve even after 10 weeks, although the wound-induced hyperplasia in EGFR wild-type grafts had resolved within 3 to 4 weeks. Thus, epithelial expression of the EGFR has complex functions in the skin. It is important in delaying follicular differentiation, may serve to protect the hair follicle from immunological reactions, and modifies both normal and wound-induced epidermal proliferation but seems dispensable for follicular proliferation. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 PMID:9176390

  7. Partial rescue of taste responses of alpha-gustducin null mice by transgenic expression of alpha-transducin.

    PubMed

    He, Wei; Danilova, Vicktoria; Zou, Shiying; Hellekant, Göran; Max, Marianna; Margolskee, Robert F; Damak, Sami

    2002-10-01

    The transduction of responses to bitter and sweet compounds utilizes guanine nucleotide binding proteins (G proteins) and their coupled receptors. Alpha-gustducin, a transducin-like G protein alpha-subunit, and rod alpha-transducin are expressed in taste receptor cells. Alpha-gustducin knockout mice have profoundly diminished behavioral and electrophysiological responses to many bitter and sweet compounds, although these mice retain residual responses to these compounds. Alpha-gustducin and rod alpha-transducin are biochemically indistinguishable in their in vitro interactions with retinal phosphodiesterase, rhodopsin and G protein betagamma-subunits. To determine if alpha-transducin can function in taste receptor cells and to compare the function of alpha-gustducin versus alpha-transducin in taste transduction in vivo, we generated transgenic mice that express alpha-transducin under the control of the alpha-gustducin promoter in the alpha-gustducin null background. Immunohistochemistry showed that the alpha-transducin transgene was expressed in about two-thirds of the alpha-gustducin lineage of taste receptor cells. Two-bottle preference tests showed that transgenic expression of rod alpha-transducin partly rescued responses to denatonium benzoate, sucrose and the artificial sweetener SC45647, but not to quinine sulfate. Gustatory nerve recordings showed a partial rescue by the transgene of the response to sucrose, SC45647 and quinine, but not to denatonium. These results demonstrate that alpha-transducin can function in taste receptor cells and transduce some taste cell responses. Our results also suggest that alpha-transducin and alpha-gustducin may differ, at least in part, in their function in these cells, although this conclusion must be qualified because of the limited fidelity of the transgene expression. PMID:12379596

  8. Impact of Genetic Counseling and Connexin-26 and Connexin-30 Testing on Deaf Identity and Comprehension of Genetic Test Results in a Sample of Deaf Adults: A Prospective, Longitudinal Study

    PubMed Central

    Palmer, Christina G. S.; Boudreault, Patrick; Baldwin, Erin E.; Sinsheimer, Janet S.

    2014-01-01

    Using a prospective, longitudinal study design, this paper addresses the impact of genetic counseling and testing for deafness on deaf adults and the Deaf community. This study specifically evaluated the effect of genetic counseling and Connexin-26 and Connexin-30 genetic test results on participants' deaf identity and understanding of their genetic test results. Connexin-26 and Connexin-30 genetic testing was offered to participants in the context of linguistically and culturally appropriate genetic counseling. Questionnaire data collected from 209 deaf adults at four time points (baseline, immediately following pre-test genetic counseling, 1-month following genetic test result disclosure, and 6-months after result disclosure) were analyzed. Four deaf identity orientations (hearing, marginal, immersion, bicultural) were evaluated using subscales of the Deaf Identity Development Scale-Revised. We found evidence that participants understood their specific genetic test results following genetic counseling, but found no evidence of change in deaf identity based on genetic counseling or their genetic test results. This study demonstrated that culturally and linguistically appropriate genetic counseling can improve deaf clients' understanding of genetic test results, and the formation of deaf identity was not directly related to genetic counseling or Connexin-26 and Connexin-30 genetic test results. PMID:25375116

  9. Mice with an NaV1.4 sodium channel null allele have latent myasthenia, without susceptibility to periodic paralysis.

    PubMed

    Wu, Fenfen; Mi, Wentao; Fu, Yu; Struyk, Arie; Cannon, Stephen C

    2016-06-01

    Over 60 mutations of SCN4A encoding the NaV1.4 sodium channel of skeletal muscle have been identified in patients with myotonia, periodic paralysis, myasthenia, or congenital myopathy. Most mutations are missense with gain-of-function defects that cause susceptibility to myotonia or periodic paralysis. Loss-of-function from enhanced inactivation or null alleles is rare and has been associated with myasthenia and congenital myopathy, while a mix of loss and gain of function changes has an uncertain relation to hypokalaemic periodic paralysis. To better define the functional consequences for a loss-of-function, we generated NaV1.4 null mice by deletion of exon 12. Heterozygous null mice have latent myasthenia and a right shift of the force-stimulus relation, without evidence of periodic paralysis. Sodium current density was half that of wild-type muscle and no compensation by retained expression of the foetal NaV1.5 isoform was detected. Mice null for NaV1.4 did not survive beyond the second postnatal day. This mouse model shows remarkable preservation of muscle function and viability for haploinsufficiency of NaV1.4, as has been reported in humans, with a propensity for pseudo-myasthenia caused by a marginal Na(+) current density to support sustained high-frequency action potentials in muscle. PMID:27048647

  10. Iron insufficiency compromises motor neurons and their mitochondrial function in Irp2-null mice.

    PubMed

    Jeong, Suh Young; Crooks, Daniel R; Wilson-Ollivierre, Hayden; Ghosh, Manik C; Sougrat, Rachid; Lee, Jaekwon; Cooperman, Sharon; Mitchell, James B; Beaumont, Carole; Rouault, Tracey A

    2011-01-01

    Genetic ablation of Iron Regulatory Protein 2 (Irp2, Ireb2), which post-transcriptionally regulates iron metabolism genes, causes a gait disorder in mice that progresses to hind-limb paralysis. Here we have demonstrated that misregulation of iron metabolism from loss of Irp2 causes lower motor neuronal degeneration with significant spinal cord axonopathy. Mitochondria in the lumbar spinal cord showed significantly decreased Complex I and II activities, and abnormal morphology. Lower motor neurons appeared to be the most adversely affected neurons, and we show that functional iron starvation due to misregulation of iron import and storage proteins, including transferrin receptor 1 and ferritin, may have a causal role in disease. We demonstrated that two therapeutic approaches were beneficial for motor neuron survival. First, we activated a homologous protein, IRP1, by oral Tempol treatment and found that axons were partially spared from degeneration. Secondly, we genetically decreased expression of the iron storage protein, ferritin, to diminish functional iron starvation. These data suggest that functional iron deficiency may constitute a previously unrecognized molecular basis for degeneration of motor neurons in mice. PMID:22003390

  11. Decreased sensory responses in osteocalcin null mutant mice imply neuropeptide function.

    PubMed

    Patterson-Buckendahl, Patricia; Sowinska, Agnieszka; Yee, Stephanie; Patel, Dhara; Pagkalinawan, Stephen; Shahid, Muhammad; Shah, Ankit; Franz, Christopher; Benjamin, Daniel E; Pohorecky, Larissa A

    2012-07-01

    Osteocalcin, the most abundant member of the family of extracellular mineral binding gamma-carboxyglutamic acid proteins is synthesized primarily by osteoblasts. Its affinity for calcium ions is believed to limit bone mineralization. Several of the numerous hormones that regulate synthesis of osteocalcin, including glucocorticoids and parathyroid hormone, are also affected by stressful stimuli that require energy for an appropriate response. Based on our observations of OC responding to stressful sensory stimuli, the expression of OC in mouse and rat sensory ganglia was confirmed. It was thus hypothesized that the behavioral responses of the OC knockout mouse to stressful sensory stimuli would be abnormal. To test this hypothesis, behaviors related to sensory aspects of the stress response were quantified in nine groups of mice, aged 4-14 months, comparing knockout with their wild-type counterparts in six distinctly different behavioral tests. Resulting data indicated the following statistically significant differences: open field grooming frequency following saline injection, wild-type > knockout; paw stimulation with Von Frey fibers, knockout < wild-type; balance beam, knockout mobility < WT; thermal sensitivity to heat (tail flick), knockout < wild-type; and cold, knockout < wild-type. Insignificant differences in hanging wire test indicate that these responses are unrelated to reduced muscle strength. Each of these disparate environmental stimuli provided data indicating alterations of responses in knockout mice that suggest participation of osteocalcin in transmission of information about those sensory stimuli. PMID:22350212

  12. Super-resolution structured illumination fluorescence microscopy of the lateral wall of the cochlea: the Connexin26/30 proteins are separately expressed in man.

    PubMed

    Liu, Wei; Edin, Fredrik; Blom, Hans; Magnusson, Peetra; Schrott-Fischer, Annelies; Glueckert, Rudolf; Santi, Peter A; Li, Hao; Laurell, Göran; Rask-Andersen, Helge

    2016-07-01

    Globally 360 million people have disabling hearing loss and, of these, 32 million are children. Human hearing relies on 15,000 hair cells that transduce mechanical vibrations to electrical signals in the auditory nerve. The process is powered by the endo-cochlear potential, which is produced by a vascularized epithelium that actively transports ions in conjunction with a gap junction (GJ) system. This "battery" is located "off-site" in the lateral wall of the cochlea. The GJ syncytium contains the GJ protein genes beta 2 (GJB2/connexin26 (Cx26)) and 6 (GJB6/connexin30 (Cx30)), which are commonly involved in hereditary deafness. Because the molecular arrangement of these proteins is obscure, we analyze GJ protein expression (Cx26/30) in human cochleae by using super-resolution structured illumination microscopy. At this resolution, the Cx26 and Cx30 proteins were visible as separate plaques, rather than being co-localized in heterotypic channels, as previously suggested. The Cx26 and Cx30 proteins thus seem not to be co-expressed but to form closely associated assemblies of GJ plaques. These results could assist in the development of strategies to treat genetic hearing loss in the future. PMID:26941236

  13. Dopamine and α-synuclein dysfunction in Smad3 null mice

    PubMed Central

    2011-01-01

    Background Parkinson's disease (PD) is characterized by dopaminergic neurodegeneration in the substantia nigra (SN). Transforming growth factor-β1 (TGF-β1) levels increase in patients with PD, although the effects of this increment remain unclear. We have examined the mesostriatal system in adult mice deficient in Smad3, a molecule involved in the intracellular TGF-β1 signalling cascade. Results Striatal monoamine oxidase (MAO)-mediated dopamine (DA) catabolism to 3,4-dihydroxyphenylacetic acid (DOPAC) is strongly increased, promoting oxidative stress that is reflected by an increase in glutathione levels. Fewer astrocytes are detected in the ventral midbrain (VM) and striatal matrix, suggesting decreased trophic support to dopaminergic neurons. The SN of these mice has dopaminergic neuronal degeneration in its rostral portion, and the pro-survival Erk1/2 signalling is diminished in nigra dopaminergic neurons, not associated with alterations to p-JNK or p-p38. Furthermore, inclusions of α-synuclein are evident in selected brain areas, both in the perikaryon (SN and paralemniscal nucleus) or neurites (motor and cingulate cortices, striatum and spinal cord). Interestingly, these α-synuclein deposits are detected with ubiquitin and PS129-α-synuclein in a core/halo cellular distribution, which resemble those observed in human Lewy bodies (LB). Conclusions Smad3 deficiency promotes strong catabolism of DA in the striatum (ST), decrease trophic and astrocytic support to dopaminergic neurons and may induce α-synuclein aggregation, which may be related to early parkinsonism. These data underline a role for Smad3 in α-synuclein and DA homeostasis, and suggest that modulatory molecules of this signalling pathway should be evaluated as possible neuroprotective agents. PMID:21995845

  14. Accelerated ovarian failure induced by 4-vinyl cyclohexene diepoxide in Nrf2 null mice.

    PubMed

    Hu, Xiaoming; Roberts, Jenny R; Apopa, Patrick L; Kan, Yuet Wai; Ma, Qiang

    2006-02-01

    Genetic and biochemical analyses have uncovered an essential role for nuclear factor erythroid 2-related factor 2 (Nrf2) in regulating phase II xenobiotic metabolism and antioxidant response. Here we show that Nrf2 protects against the ovarian toxicity of 4-vinylcyclohexene diepoxide (VCD) in mice. Nrf2-/- female mice exposed to VCD exhibit an age-dependent decline in reproduction leading to secondary infertility accompanied by hypergonadotropic hypogonadism after 30 weeks of age. VCD is shown to selectively destroy small ovarian follicles, resulting in early depletion of functional follicles. Treatment with VCD induces apoptotic death in cultured cells and in ovarian follicles, suggesting apoptosis as a mechanism of follicle loss. Loss of Nrf2 function blocks the basal and inducible expression of microsomal epoxide hydrolase, a key enzyme in the detoxification of VCD, and increases the oxidative stress in cells that is further exacerbated by VCD. Foxo3a, a repressor in the early stages of follicle activation, displays reduced expression in Nrf2-/- ovaries, causing accelerated growth of follicles in the absence of exposure to exogenous chemicals. Furthermore, Foxo3a is degraded through the 26S proteasome pathway in untreated cells and is induced by VCD via both Nrf2-dependent transcription and protein stabilization. This study demonstrates that Nrf2 serves as an essential sensor and regulator of chemical homeostasis in ovarian cells, protecting the cells from toxic chemicals by controlling metabolic detoxification, reactive oxygen species defense, and Foxo3a expression. In addition, these findings raise the possibility that exposure to environmental or occupational ovotoxicants plays a role in the premature ovarian failure commonly associated with infertility and premature aging in women. PMID:16428448

  15. A human FSHB transgene encoding the double N-glycosylation mutant (Asn(7Δ) Asn(24Δ)) FSHβ subunit fails to rescue Fshb null mice.

    PubMed

    Wang, Huizhen; Butnev, Vladimir; Bousfield, George R; Kumar, T Rajendra

    2016-05-01

    Follicle-stimulating hormone (FSH) is a gonadotrope-derived heterodimeric glycoprotein. Both the common α- and hormone-specific β subunits contain Asn-linked N-glycan chains. Recently, macroheterogeneous FSH glycoforms consisting of β-subunits that differ in N-glycan number were identified in pituitaries of several species and subsequently the recombinant human FSH glycoforms biochemically characterized. Although chemical modification and in vitro site-directed mutagenesis studies defined the roles of N-glycans on gonadotropin subunits, in vivo functional analyses in a whole-animal setting are lacking. Here, we have generated transgenic mice with gonadotrope-specific expression of either an HFSHB(WT) transgene that encodes human FSHβ WT subunit or an HFSHB(dgc) transgene that encodes a human FSHβ(Asn7Δ 24Δ) double N-glycosylation site mutant subunit, and separately introduced these transgenes onto Fshb null background using a genetic rescue strategy. We demonstrate that the human FSHβ(Asn7Δ 24Δ) double N-glycosylation site mutant subunit, unlike human FSHβ WT subunit, inefficiently combines with the mouse α-subunit in pituitaries of Fshb null mice. FSH dimer containing this mutant FSHβ subunit is inefficiently secreted with very low levels detectable in serum. Fshb null male mice expressing HFSHB(dgc) transgene are fertile and exhibit testis tubule size and sperm number similar to those of Fshb null mice. Fshb null female mice expressing the mutant, but not WT human FSHβ subunit-containing FSH dimer are infertile, demonstrate no evidence of estrus cycles, and many of the FSH-responsive genes remain suppressed in their ovaries. Thus, HFSHB(dgc) unlike HFSHB(WT) transgene does not rescue Fshb null mice. Our genetic approach provides direct in vivo evidence that N-linked glycans on FSHβ subunit are essential for its efficient assembly with the α-subunit to form FSH heterodimer in pituitary. Our studies also reveal that N-glycans on FSHβ subunit are

  16. Insulin decreases atherosclerotic plaque burden and increases plaque stability via nitric oxide synthase in apolipoprotein E-null mice.

    PubMed

    Mori, Yusaku; Chiang, Simon; Bendeck, Michelle P; Giacca, Adria

    2016-08-01

    It has been argued whether insulin accelerates or prevents atherosclerosis. Although results from in vitro studies have been conflicting, recent in vivo mice studies demonstrated antiatherogenic effects of insulin. Insulin is a known activator of endothelial nitric oxide synthase (NOS), leading to increased production of NO, which has potent antiatherogenic effects. We aimed to examine the role of NOS in the protective effects of insulin against atherosclerosis. Male apolipoprotein E-null mice (8 wk old) fed a high-cholesterol diet (1.25% cholesterol) were assigned to the following 12-wk treatments: control, insulin (0.05 U/day via subcutaneous pellet), N(ω)-nitro-l-arginine methyl ester hydrochloride (l-NAME, via drinking water at 100 mg/l), and insulin plus l-NAME. Insulin reduced atherosclerotic plaque burden in the descending aorta by 42% compared with control (plaque area/aorta lumen area: control, 16.5 ± 1.9%; insulin, 9.6 ± 1.3%, P < 0.05). Although insulin did not decrease plaque burden in the aortic sinus, macrophage accumulation in the plaque was decreased by insulin. Furthermore, insulin increased smooth muscle actin and collagen content and decreased plaque necrosis, consistent with increased plaque stability. In addition, insulin treatment increased plasma NO levels, decreased inducible NOS staining, and tended to increase phosphorylated vasodilator-stimulated phosphoprotein staining in the plaques of the aortic sinus. All these effects of insulin were abolished by coadministration of l-NAME, whereas l-NAME alone showed no effect. Insulin also tended to increase phosphorylated endothelial NOS and total neuronal NOS staining, effects not modified by l-NAME. In conclusion, we demonstrate that insulin treatment decreases atherosclerotic plaque burden and increases plaque stability through NOS-dependent mechanisms. PMID:27221119

  17. Distribution of glycylsarcosine and cefadroxil among cerebrospinal fluid, choroid plexus, and brain parenchyma after intracerebroventricular injection is markedly different between wild-type and Pept2 null mice.

    PubMed

    Smith, David E; Hu, Yongjun; Shen, Hong; Nagaraja, Tavarekere N; Fenstermacher, Joseph D; Keep, Richard F

    2011-01-01

    The purpose of this study was to define the cerebrospinal fluid (CSF) clearance kinetics, choroid plexus uptake, and parenchymal penetration of PEPT2 substrates in different regions of the brain after intracerebroventricular administration. To accomplish these objectives, we performed biodistribution studies using [(14)C]glycylsarcosine (GlySar) and [(3)H]cefadroxil, along with quantitative autoradiography of [(14)C]GlySar, in wild-type and Pept2 null mice. We found that PEPT2 deletion markedly reduced the uptake of GlySar and cefadroxil in choroid plexuses at 60 mins by 94% and 82% (P<0.001), respectively, and lowered their CSF clearances by about fourfold. Autoradiography showed that GlySar concentrations in the lateral, third, and fourth ventricle choroid plexuses were higher in wild-type as compared with Pept2 null mice (P<0.01). Uptake of GlySar by the ependymal-subependymal layer and septal region was higher in wild-type than in null mice, but the half-distance of penetration into parenchyma was significantly less in wild-type mice. The latter is probably because of the clearance of GlySar from interstitial fluid by brain cells expressing PEPT2, which stops further penetration. These studies show that PEPT2 knockout can significantly modify the spatial distribution of GlySar and cefadroxil (and presumably other peptides/mimetics and peptide-like drugs) in brain. PMID:20571525

  18. Drosophila atonal fully rescues the phenotype of Math1 null mice: new functions evolve in new cellular contexts

    NASA Technical Reports Server (NTRS)

    Wang, Vincent Y.; Hassan, Bassem A.; Bellen, Hugo J.; Zoghbi, Huda Y.

    2002-01-01

    Many genes share sequence similarity between species, but their properties often change significantly during evolution. For example, the Drosophila genes engrailed and orthodenticle and the onychophoran gene Ultrabithorax only partially substitute for their mouse or Drosophila homologs. We have been analyzing the relationship between atonal (ato) in the fruit fly and its mouse homolog, Math1. In flies, ato acts as a proneural gene that governs the development of chordotonal organs (CHOs), which serve as stretch receptors in the body wall and joints and as auditory organs in the antennae. In the fly CNS, ato is important not for specification but for axonal arborization. Math1, in contrast, is required for the specification of cells in both the CNS and the PNS. Furthermore, Math1 serves a role in the development of secretory lineage cells in the gut, a function that does not parallel any known to be served by ato. We wondered whether ato and Math1 might be more functionally homologous than they appear, so we expressed Math1 in ato mutant flies and ato in Math1 null mice. To our surprise, the two proteins are functionally interchangeable.

  19. Nuclear Factor-κB Activation and Postischemic Inflammation Are Suppressed in CD36-Null Mice after Middle Cerebral Artery Occlusion

    PubMed Central

    Kunz, Alexander; Abe, Takato; Hochrainer, Karin; Shimamura, Munehisa; Anrather, Josef; Racchumi, Gianfranco; Zhou, Ping; Iadecola, Costantino

    2008-01-01

    CD36, a class-B scavenger receptor involved in multiple functions, including inflammatory signaling, may also contribute to ischemic brain injury through yet unidentified mechanisms. We investigated whether CD36 participates in the molecular events underlying the inflammatory reaction that accompanies cerebral ischemia and may contribute to the tissue damage. We found that activation of nuclear factor-κB, a transcription factor that coordinates postischemic gene expression, is attenuated in CD36-null mice subjected to middle cerebral artery occlusion. The infiltration of neutrophils and the glial reaction induced by cerebral ischemia were suppressed. Treatment with an inhibitor of inducible nitric oxide synthase, an enzyme that contributes to the tissue damage, reduced ischemic brain injury in wild-type mice, but not in CD36 nulls. In contrast to cerebral ischemia, the molecular and cellular inflammatory changes induced by intracerebroventricular injection of interleukin-1β were not attenuated in CD36-null mice. The findings unveil a novel role of CD36 in early molecular events leading to nuclear factor-κB activation and postischemic inflammation. Inhibition of CD36 signaling may be a valuable therapeutic approach to counteract the deleterious effects of postischemic inflammation. PMID:18272685

  20. Recoupling of eNOS with Folic Acid Prevents Abdominal Aortic Aneurysm Formation in Angiotensin II-Infused Apolipoprotein E Null Mice

    PubMed Central

    Siu, Kin Lung; Miao, Xiao Niu; Cai, Hua

    2014-01-01

    We have previously shown that eNOS uncoupling mediates abdominal aortic aneurysm (AAA) formation in hph-1 mice. In the present study we examined whether recoupling of eNOS prevents AAA formation in a well-established model of Angiotensin II-infused apolipoprotein E (apoE) null mice by targeting some common pathologies of AAA. Infusion of Ang II resulted in a 92% incidence rate of AAA in the apoE null animals. In a separate group, animals were treated orally with folic acid (FA), which is known to recouple eNOS through augmentation of dihydrofolate reductase (DHFR) function. This resulted in a reduction of AAA rate to 19.5%. Imaging with ultrasound showed that FA markedly inhibited expansion of abdominal aorta. FA also abolished elastin breakdown and macrophage infiltration in the AAA animals. The eNOS uncoupling activity, assessed by L-NAME-sensitive superoxide production, was minimal at baseline but greatly exaggerated with Ang II infusion, which was completely attenuated by FA. This was accompanied by markedly improved tetrahydrobiopterin and nitric oxide bioavailability. Furthermore, the expression and activity of DHFR was decreased in Ang II-infused apoE null mice specifically in the endothelial cells, while FA administration resulted in its recovery. Taken together, these data further establish a significant role of uncoupled eNOS in mediating AAA formation, and a universal efficacy of FA in preventing AAA formation via restoration of DHFR to restore eNOS function. PMID:24558445

  1. Molecular profiles of Quadriceps muscle in myostatin-null mice reveal PI3K and apoptotic pathways as myostatin targets

    PubMed Central

    Chelh, Ilham; Meunier, Bruno; Picard, Brigitte; Reecy, Mark James; Chevalier, Catherine; Hocquette, Jean-François; Cassar-Malek, Isabelle

    2009-01-01

    Background Myostatin (MSTN), a member of the TGF-β superfamily, has been identified as a negative regulator of skeletal muscle mass. Inactivating mutations in the MSTN gene are responsible for the development of a hypermuscular phenotype. In this study, we performed transcriptomic and proteomic analyses to detect altered expression/abundance of genes and proteins. These differentially expressed genes and proteins may represent new molecular targets of MSTN and could be involved in the regulation of skeletal muscle mass. Results Transcriptomic analysis of the Quadriceps muscles of 5-week-old MSTN-null mice (n = 4) and their controls (n = 4) was carried out using microarray (human and murine oligonucleotide sequences) of 6,473 genes expressed in muscle. Proteomic profiles were analysed using two-dimensional gel electrophoresis coupled with mass spectrometry. Comparison of the transcriptomic profiles revealed 192 up- and 245 down- regulated genes. Genes involved in the PI3K pathway, insulin/IGF pathway, carbohydrate metabolism and apoptosis regulation were up-regulated. Genes belonging to canonical Wnt, calcium signalling pathways and cytokine-receptor cytokine interaction were down-regulated. Comparison of the protein profiles revealed 20 up- and 18 down-regulated proteins spots. Knockout of the MSTN gene was associated with up-regulation of proteins involved in glycolytic shift of the muscles and down-regulation of proteins involved in oxidative energy metabolism. In addition, an increased abundance of survival/anti-apoptotic factors were observed. Conclusion All together, these results showed a differential expression of genes and proteins related to the muscle energy metabolism and cell survival/anti-apoptotic pathway (e.g. DJ-1, PINK1, 14-3-3ε protein, TCTP/GSK-3β). They revealed the PI3K and apoptotic pathways as MSTN targets and are in favour of a role of MSTN as a modulator of cell survival in vivo. PMID:19397818

  2. Pro- and anti-atherogenic effects of a dominant negative P465L mutation of PPARγ in apolipoprotein E-null mice

    PubMed Central

    Pendse, Avani A.; Johnson, Lance A.; Kim, Hyung-Suk; McNair, Marcus; Nipp, C. Taylor; Wilhelm, Carolyn; Maeda, Nobuyo

    2012-01-01

    Objective The dominant-negative mutation, P467L, in Peroxisome Proliferator Activated Receptor gamma (PPARγ) affects adipose tissue distribution, insulin sensitivity and blood pressure in heterozygous humans. We hypothesized that the equivalent mutation, PPARγ-P465L, in mice will worsen atherosclerosis. Methods and Results ApolipoproteinE-null mice with and without PPARγ-P465L mutation were bred in 129S6 inbred genetic background. Mild hypertension and lipodystrophy of PPARγ-P465L persisted in the apoE-null background. Glucose homeostasis was normal, but plasma adiponectin was significantly lower and resistin was higher in PPARγ-P465L mice. Plasma cholesterol and lipoprotein distribution were not different, but plasma triglycerides tended to be reduced. Surprisingly, there were no overall changes in the atherosclerotic plaque size or composition. PPARγ-P465L macrophages had a small decrease in CD-36 mRNA and a small yet significant reduction in VLDL uptake in culture. In unloaded apoE-null macrophages with PPARγ-P465L, cholesterol uptake was reduced while apoAI-mediated efflux was increased. However, when cells were cholesterol loaded in presence of acetylated LDL, no genotype difference in uptake or efflux was apparent. A reduction of VCAM1 expression in aorta suggests a relatively anti-atherogenic vascular environment in mice with PPARγ-P465L. Conclusions Small, competing pro- and anti-atherogenic effects of PPARγ-P465L mutation result in unchanged plaque development in apoE-deficient mice. PMID:22539598

  3. Long-term improvements in sensory inhibition with gestational choline supplementation linked to α7 nicotinic receptors through studies in Chrna7 null mutation mice.

    PubMed

    Stevens, Karen E; Choo, Kevin S; Stitzel, Jerry A; Marks, Michael J; Adams, Catherine E

    2014-03-13

    Perinatal choline supplementation has produced several benefits in rodent models, from improved learning and memory to protection from the behavioral effects of fetal alcohol exposure. We have shown that supplemented choline through gestation and lactation produces long-term improvement in deficient sensory inhibition in DBA/2 mice which models a similar deficit in schizophrenia patients. The present study extends that research by feeding normal or supplemented choline diets to DBA/2 mice carrying the null mutation for the α7 nicotinic receptor gene (Chrna7). DBA/2 mice heterozygotic for Chrna7 were bred together. Dams were placed on supplemented (5 gm/kg diet) or normal (1.1 gm/kg diet) choline at mating and remained on the specific diet until offspring weaning. Thereafter, offspring were fed standard rodent chow. Adult offspring were assessed for sensory inhibition. Brains were obtained to ascertain hippocampal α7 nicotinic receptor levels. Choline-supplemented mice heterozygotic or null-mutant for Chrna7 failed to show improvement in sensory inhibition. Only wildtype choline-supplemented mice showed improvement with the effect solely through a decrease in test amplitude. This supports the hypothesis that gestational-choline supplementation is acting through the α7 nicotinic receptor to improve sensory inhibition. Although there was a significant gene-dose-related change in hippocampal α7 receptor numbers, binding studies did not reveal any choline-dose-related change in binding in any hippocampal region, the interaction being driven by a significant genotype main effect (wildtype>heterozygote>null mutant). These data parallel a human study wherein the offspring of pregnant women receiving choline supplementation during gestation, showed better sensory inhibition than offspring of women on placebo. PMID:24462939

  4. Leptin receptor null mice with reexpression of LepR in GnRHR expressing cells display elevated FSH levels but remain in a prepubertal state.

    PubMed

    Allen, Susan J; Garcia-Galiano, David; Borges, Beatriz C; Burger, Laura L; Boehm, Ulrich; Elias, Carol F

    2016-06-01

    Leptin signals energy sufficiency to the reproductive hypothalamic-pituitary-gonadal (HPG) axis. Studies using genetic models have demonstrated that hypothalamic neurons are major players mediating these effects. Leptin receptor (LepR) is also expressed in the pituitary gland and in the gonads, but the physiological effects of leptin in these sites are still unclear. Female mice with selective deletion of LepR in a subset of gonadotropes show normal pubertal development but impaired fertility. Conditional deletion approaches, however, often result in redundancy or developmental adaptations, which may compromise the assessment of leptin's action in gonadotropes for pubertal maturation. To circumvent these issues, we adopted a complementary genetic approach and assessed if selective reexpression of LepR only in gonadotropes is sufficient to enable puberty and improve fertility of LepR null female mice. We initially assessed the colocalization of gonadotropin-releasing hormone receptor (GnRHR) and LepR in the HPG axis using GnRHR-IRES-Cre (GRIC) and LepR-Cre reporter (tdTomato or enhanced green fluorescent protein) mice. We found that GRIC and leptin-induced phosphorylation of STAT3 are expressed in distinct hypothalamic neurons. Whereas LepR-Cre was observed in theca cells, GRIC expression was rarely found in the ovarian parenchyma. In contrast, a subpopulation of gonadotropes expressed the LepR-Cre reporter gene (tdTomato). We then crossed the GRIC mice with the LepR null reactivable (LepR(loxTB)) mice. These mice showed an increase in FSH levels, but they remained in a prepubertal state. Together with previous findings, our data indicate that leptin-selective action in gonadotropes serves a role in adult reproductive physiology but is not sufficient to allow pubertal maturation in mice. PMID:27101301

  5. Partial rescue of epithelial phenotype in integrin beta4 null mice by a keratin-5 promoter driven human integrin beta4 transgene.

    PubMed

    van der Neut, R; Cachaço, A S; Thorsteinsdóttir, S; Janssen, H; Prins, D; Bulthuis, J; van der Valk, M; Calafat, J; Sonnenberg, A

    1999-11-01

    Integrin beta4 null mice exhibit extensive epidermal detachment, reminiscent of the human skin blistering disease junctional epidermolysis bullosa associated with pyloric atresia. Hemidesmosomes, the stable adhesion structures of squamous epithelia, are not formed in the absence of alpha6beta4. Null mutant mice die shortly after birth, but apart from their striking epithelial phenotype, no obvious developmental defects have been observed. To elucidate the cause of death in these mice, we generated transgenic mice with a heterologous construct consisting of the squamous epithelial-specific keratin-5 promoter and a human integrin beta4 subunit cDNA. The transgene was not expressed in the presence of endogenous beta4, probably as a result of competition for a limited pool of alpha6 subunits. In a beta4 null background, however, the transgene was expressed, and its expression pattern followed that of squamous epithelial-specific keratins. These rescued pups appeared healthy and ultrastructural analysis revealed that the interspecies heterodimer alpha6(mouse)/beta4(human) was sufficient to trigger the assembly of hemidesmosomes. After a variable period of up to 48 hours after birth these animals began to exhibit haemorrhages at the plantar and palmar areas. We observed the formation of small blisters and found that the transgene was not detectably expressed in this region, which is devoid of hair follicles. The rescued neonates became increasingly cyanotic and died soon after the onset of this phenomenon. We performed a developmental study of the expression of beta4 in the complete respiratory tract, but we found no correlation between the spatiotemporal distribution of beta4 and the onset of the respiratory insufficiency. It became clear, however, that there was a gradual detachment of squamous epithelia in the oral and nasal cavities which led to obstruction of the respiratory tract, suggesting that in beta4 null and rescued mice, neonatal death was a direct

  6. Role of gamma carboxylated Glu47 in connexin 26 hemichannel regulation by extracellular Ca{sup 2+}: Insight from a local quantum chemistry study

    SciTech Connect

    Zonta, Francesco; Mammano, Fabio; Torsello, Mauro; Fortunati, Nicola; Orian, Laura; Polimeno, Antonino

    2014-02-28

    Graphical abstract: - Highlights: • QM calculations show that Ca{sup 2+} binds to γGlu47 in connexin hemichannels. • Molecular models of increasing size are employed in hybrid DFT calculations. • Ca{sup 2+} binding affects the interaction between γGlu47 and Arg75, Arg184. • Ca{sup 2+} binding alters the structure in a critical region of connexin hemichannels. - Abstract: Connexin hemichannels are regulated by several gating mechanisms, some of which depend critically on the extracellular Ca{sup 2+} concentration ([Ca{sup 2+}]{sub e}). It is well established that hemichannel activity is inhibited at normal (∼1 mM) [Ca{sup 2+}]{sub e}, whereas lowering [Ca{sup 2+}]{sub e} to micromolar levels fosters hemichannel opening. Atomic force microscopy imaging shows significant and reversible changes of pore diameter at the extracellular mouth of Cx26 hemichannels exposed to different [Ca{sup 2+}]{sub e}, however, the underlying molecular mechanisms are not fully elucidated. Analysis of the crystal structure of connexin 26 (Cx26) gap junction channels, corroborated by molecular dynamics (MD) simulations, suggests that several negatively charged amino acids create a favorable environment for low-affinity Ca{sup 2+} binding within the extracellular vestibule of the Cx26 hemichannel. In particular a highly conserved glutammic acid, found in position 47 in most connexins, is thought to undergo post translational gamma carboxylation (γGlu47), and is thus likely to play an important role in Ca{sup 2+} coordination. γGlu47 may also form salt bridges with two conserved arginines (Arg75 and Arg184 in Cx26), which are considered important in stabilizing the structure of the extracellular region. Using a combination of quantum chemistry methods, we analyzed the interaction between γGlu47, Arg75 and Arg184 in a Cx26 hemichannel model both in the absence and in the presence of Ca{sup 2+}. We show that Ca{sup 2+} imparts significant local structural changes and speculate

  7. Hepatic effects of repeated oral administration of diclofenac to hepatic cytochrome P450 reductase null (HRN™) and wild-type mice.

    PubMed

    Akingbasote, James A; Foster, Alison J; Wilson, Ian; Sarda, Sunil; Jones, Huw B; Kenna, J Gerry

    2016-04-01

    Hepatic NADPH-cytochrome P450 oxidoreductase null (HRN™) mice exhibit normal hepatic and extrahepatic biotransformation enzyme activities when compared to wild-type (WT) mice, but express no functional hepatic cytochrome P450 activities. When incubated in vitro with [(14)C]-diclofenac, liver microsomes from WT mice exhibited extensive biotransformation to oxidative and glucuronide metabolites and covalent binding to proteins was also observed. In contrast, whereas glucuronide conjugates and a quinone-imine metabolite were formed when [(14)C]-diclofenac was incubated with HRN™ mouse liver, only small quantities of P450-derived oxidative metabolites were produced in these samples and covalent binding to proteins was not observed. Livers from vehicle-treated HRN™ mice exhibited enhanced lipid accumulation, bile duct proliferation, hepatocellular degeneration and necrosis and inflammatory cell infiltration, which were not present in livers from WT mice. Elevated liver-derived alanine aminotransferase, glutamate dehydrogenase and alkaline phosphatase activities were also observed in plasma from HRN™ mice. When treated orally with diclofenac for 7 days, at 30 mg/kg/day, the severities of the abnormal liver histopathology and plasma liver enzyme findings in HRN™ mice were reduced markedly. Oral diclofenac administration did not alter the liver histopathology or elevate plasma enzyme activities of WT mice. These findings indicate that HRN™ mice are valuable for exploration of the role played by hepatic P450s in drug biotransformation, but poorly suited to investigations of drug-induced liver toxicity. Nevertheless, studies in HRN™ mice could provide novel insights into the role played by inflammation in liver injury and may aid the evaluation of new strategies for its treatment. PMID:25820915

  8. Col6a1 Null Mice as a Model to Study Skin Phenotypes in Patients with Collagen VI Related Myopathies: Expression of Classical and Novel Collagen VI Variants during Wound Healing

    PubMed Central

    Lettmann, Sandra; Bloch, Wilhelm; Maaß, Tobias; Niehoff, Anja; Schulz, Jan-Niklas; Eckes, Beate; Eming, Sabine A.; Bonaldo, Paolo; Paulsson, Mats; Wagener, Raimund

    2014-01-01

    Patients suffering from collagen VI related myopathies caused by mutations in COL6A1, COL6A2 and COL6A3 often also display skin abnormalities, like formation of keloids or “cigarette paper” scars, dry skin, striae rubrae and keratosis pilaris (follicular keratosis). Here we evaluated if Col6a1 null mice, an established animal model for the muscle changes in collagen VI related myopathies, are also suitable for the study of mechanisms leading to the skin pathology. We performed a comprehensive study of the expression of all six collagen VI chains in unwounded and challenged skin of wild type and Col6a1 null mice. Expression of collagen VI chains is regulated in both skin wounds and bleomycin-induced fibrosis and the collagen VI α3 chain is proteolytically processed in both wild type and Col6a1 null mice. Interestingly, we detected a decreased tensile strength of the skin and an altered collagen fibril and basement membrane architecture in Col6a1 null mice, the latter being features that are also found in collagen VI myopathy patients. Although Col6a1 null mice do not display an overt wound healing defect, these mice are a relevant animal model to study the skin pathology in collagen VI related disease. PMID:25158062

  9. D-4F reduces EO6 immunoreactivity, SREBP-1c mRNA levels, and renal inflammation in LDL receptor-null mice fed a Western diet.

    PubMed

    Buga, Georgette M; Frank, Joy S; Mottino, Giuliano A; Hakhamian, Ashkan; Narasimha, Ajay; Watson, Andrew D; Yekta, Babak; Navab, Mohamad; Reddy, Srinivasa T; Anantharamaiah, G M; Fogelman, Alan M

    2008-01-01

    LDL receptor-null (LDLR(-/-)) mice on a Western diet (WD) develop endothelial dysfunction and atherosclerosis, which are improved by the apolipoprotein A-I (apoA-I) mimetic peptide D-4F. Focusing on the kidney, LDLR(-/-)mice were fed a WD with D-4F or the inactive control peptide scrambled D-4F (ScD-4F) added to their drinking water. The control mice (ScD-4F) developed glomerular changes, increased immunostaining for MCP-1/CCL2 chemokine, increased macrophage CD68 and F4/80 antigens, and increased oxidized phospholipids recognized by the EO6 monoclonal antibody in both glomerular and tublo-interstitial areas. All of these parameters were significantly reduced by D-4F treatment, approaching levels found in wild-type C57BL/6J or LDLR(-/-) mice fed a chow diet. Sterol-regulatory element binding protein-1c (SREBP-1c) mRNA levels and triglyceride levels were elevated in the kidneys of the control mice (ScD-4F) fed the WD compared with C57BL/6J and LDLR(-/-) mice on chow (P < 0.001 and P < 0.001, respectively) and compared with D-4F-treated mice on the WD (P < 0.01). There was no significant difference in plasma lipids, lipoproteins, glucose, blood pressure, or renal apoB levels between D-4F- and ScD-4F-treated mice. We conclude that D-4F reduced renal oxidized phospholipids, resulting in lower expression of SREBP-1c, which, in turn, resulted in lower triglyceride content and reduced renal inflammation. PMID:17925450

  10. Pathological Type-2 Immune Response, Enhanced Tumor Growth, and Glucose Intolerance in Retnlβ (RELMβ) Null Mice: A Model of Intestinal Immune System Dysfunction in Disease Susceptibility.

    PubMed

    Wernstedt Asterholm, Ingrid; Kim-Muller, Ja Young; Rutkowski, Joseph M; Crewe, Clair; Tao, Caroline; Scherer, Philipp E

    2016-09-01

    Resistin, and its closely related homologs, the resistin-like molecules (RELMs) have been implicated in metabolic dysregulation, inflammation, and cancer. Specifically, RELMβ, expressed predominantly in the goblet cells in the colon, is released both apically and basolaterally, and is hence found in both the intestinal lumen in the mucosal layer as well as in the circulation. RELMβ has been linked to both the pathogenesis of colon cancer and type 2 diabetes. RELMβ plays a complex role in immune system regulation, and the impact of loss of function of RELMβ on colon cancer and metabolic regulation has not been fully elucidated. We therefore tested whether Retnlβ (mouse ortholog of human RETNLβ) null mice have an enhanced or reduced susceptibility for colon cancer as well as metabolic dysfunction. We found that the lack of RELMβ leads to increased colonic expression of T helper cell type-2 cytokines and IL-17, associated with a reduced ability to maintain intestinal homeostasis. This defect leads to an enhanced susceptibility to the development of inflammation, colorectal cancer, and glucose intolerance. In conclusion, the phenotype of the Retnlβ null mice unravels new aspects of inflammation-mediated diseases and strengthens the notion that a proper intestinal barrier function is essential to sustain a healthy phenotype. PMID:27397737

  11. Caveolin-3 null mice show a loss of caveolae, changes in the microdomain distribution of the dystrophin-glycoprotein complex, and t-tubule abnormalities.

    PubMed

    Galbiati, F; Engelman, J A; Volonte, D; Zhang, X L; Minetti, C; Li, M; Hou, H; Kneitz, B; Edelmann, W; Lisanti, M P

    2001-06-15

    Caveolin-3, a muscle-specific caveolin-related protein, is the principal structural protein of caveolae membrane domains in striated muscle cells. Recently, we identified a novel autosomal dominant form of limb-girdle muscular dystrophy (LGMD-1C) in humans that is due to mutations within the coding sequence of the human caveolin-3 gene (3p25). These LGMD-1C mutations lead to an approximately 95% reduction in caveolin-3 protein expression, i.e. a caveolin-3 deficiency. Here, we created a caveolin-3 null (CAV3 -/-) mouse model, using standard homologous recombination techniques, to mimic a caveolin-3 deficiency. We show that these mice lack caveolin-3 protein expression and sarcolemmal caveolae membranes. In addition, analysis of skeletal muscle tissue from these caveolin-3 null mice reveals: (i) mild myopathic changes; (ii) an exclusion of the dystrophin-glycoprotein complex from lipid raft domains; and (iii) abnormalities in the organization of the T-tubule system, with dilated and longitudinally oriented T-tubules. These results have clear mechanistic implications for understanding the pathogenesis of LGMD-1C at a molecular level. PMID:11259414

  12. Daidzein prevents the increase in CD4+CD28null T cells and B lymphopoesis in ovariectomized mice: a key mechanism for anti-osteoclastogenic effect.

    PubMed

    Tyagi, Abdul Malik; Srivastava, Kamini; Sharan, Kunal; Yadav, Dinesh; Maurya, Rakesh; Singh, Divya

    2011-01-01

    Estrogen deficiency leads to an upregulation of TNF-α producing T cells and B-lymphopoesis which augments osteoclastogenesis. Estrogen deficiency also increases the population of premature senescent CD4⁺ CD28null T cells which secrete a higher amount of TNF-α thus leading to enhanced osteoclastogenesis. Isoflavonoids like daidzein and genistein are found mostly in soybeans, legumes, and peas. These share structural similarity with 17β-stradiol (E2) and have osteoprotective role. This study explores the effect of daidzein (Daid) on the proliferation of TNF-α producing T cells, premature senescent T cells and B cell lymphopoesis under estrogen deficient conditions. For this study adult Balb/c mice were treated with Daid at 10 mg/kg body weight dose by oral gavage daily post ovariectomy (Ovx). After six weeks animals were autopsied and bone marrow and spleen cells were collected for FACS analysis. Blood serum was collected for ELISA. It was observed that Ovx mice treated with Daid for six weeks show reduction in Ovx induced expansion of CD4⁺ T cells in bone marrow and spleen when analysed by flow cytometry. Estrogen deficiency led to increased prevalence of TNF-α secreting CD4⁺CD28null T cells, however, treatment with Daid increased the percentage of CD4⁺CD28⁺ T cells. Co-culture of CD4⁺CD28null T cells and bone marrow resulted in enhanced osteoclastogenesis as evident by increased tartarate resistant acid phosphatase (TRAP) expression, an osteoclast marker. However, treatment with Daid resulted in reduced osteoclastogenesis in CD4⁺CD28null T cells and bone marrow cell co-culture. Daid also regulated B lymphopoesis and decreased mRNA levels of RANKL in B220⁺ cells. Taken together, we propose that one of the mechanisms by which Daid prevents bone loss is by reversing the detrimental immune changes as a result of estrogen deficiency. PMID:21731677

  13. Minocycline attenuates HIV-1 infection and suppresses chronic immune activation in humanized NOD/LtsZ-scidIL-2Rγnull mice

    PubMed Central

    Singh, Maneesh; Singh, Pratibha; Vaira, Dolores; Amand, Mathieu; Rahmouni, Souad; Moutschen, Michel

    2014-01-01

    More than a quarter of a century of research has established chronic immune activation and dysfunctional T cells as central features of chronic HIV infection and subsequent immunodeficiency. Consequently, the search for a new immunomodulatory therapy that could reduce immune activation and improve T-cell function has been increased. However, the lack of small animal models for in vivo HIV study has hampered progress. In the current study, we have investigated a model of cord blood haematopoietic progenitor cells (CB-HPCs) -transplanted humanized NOD/LtsZ-scidIL-2Rγnull mice in which progression of HIV infection is associated with widespread chronic immune activation and inflammation. Indeed, HIV infection in humanized NSG mice caused up-regulation of several T-cell immune activation markers such as CD38, HLA-DR, CD69 and co-receptor CCR5. T-cell exhaustion markers PD-1 and CTLA-4 were found to be significantly up-regulated on T cells. Moreover, increased plasmatic levels of lipopolysaccharide, sCD14 and interleukin-10 were also observed in infected mice. Treatment with minocycline resulted in a significant decrease of expression of cellular and plasma immune activation markers, inhibition of HIV replication and improved T-cell counts in HIV-infected humanized NSG mice. The study demonstrates that minocycline could be an effective, low-cost adjunctive treatment to regulate chronic immune activation and replication of HIV. PMID:24409837

  14. Increased anxiety in corticotropin-releasing factor type 2 receptor-null mice requires recent acute stress exposure and is associated with dysregulated serotonergic activity in limbic brain areas

    PubMed Central

    2014-01-01

    Background Corticotropin-releasing factor type 2 receptors (CRFR2) are suggested to facilitate successful recovery from stress to maintain mental health. They are abundant in the midbrain raphe nuclei, where they regulate serotonergic neuronal activity and have been demonstrated to mediate behavioural consequences of stress. Here, we describe behavioural and serotonergic responses consistent with maladaptive recovery from stressful challenge in CRFR2-null mice. Results CRFR2-null mice showed similar anxiety levels to control mice before and immediately after acute restraint stress, and also after cessation of chronic stress. However, they showed increased anxiety by 24 hours after restraint, whether or not they had been chronically stressed. Serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) contents were quantified and the level of 5-HIAA in the caudal dorsal raphe nucleus (DRN) was increased under basal conditions in CRFR2-null mice, indicating increased 5-HT turnover. Twenty-four hours following restraint, 5-HIAA was decreased only in CRFR2-null mice, suggesting that they had not fully recovered from the challenge. In efferent limbic structures, CRFR2-null mice showed lower levels of basal 5-HT in the lateral septum and subiculum, and again showed a differential response to restraint stress from controls. Local cerebral glucose utilization (LCMRglu) revealed decreased neuronal activity in the DRN of CRFR2-null mice under basal conditions. Following 5-HT receptor agonist challenge, LCMRglu responses indicated that 5-HT1A receptor responses in the DRN were attenuated in CRFR2-null mice. However, postsynaptic 5-HT receptor responses in forebrain regions were intact. Conclusions These results suggest that CRFR2 are required for proper functionality of 5-HT1A receptors in the raphe nuclei, and are key to successful recovery from stress. This disrupted serotonergic function in CRFR2-null mice likely contributes to their stress-sensitive phenotype. The 5-HT

  15. ZnT4 (SLC30A4)-null ("lethal milk") mice have defects in mammary gland secretion and hallmarks of precocious involution during lactation.

    PubMed

    McCormick, Nicholas H; Lee, Sooyeon; Hennigar, Stephen R; Kelleher, Shannon L

    2016-01-01

    During lactation, highly specialized secretory mammary epithelial cells (MECs) produce and secrete huge quantities of nutrients and nonnutritive factors into breast milk. The zinc (Zn) transporter ZnT4 (SLC30A4) transports Zn into the trans-Golgi apparatus for lactose synthesis, and across the apical cell membrane for efflux from MECs into milk. This is consistent with observations in "lethal milk" (lm/lm) mice, which have a truncation mutation in SLC30A4, and present with not only low milk Zn concentration, but also smaller mammary glands, decreased milk volume, and lactation failure by lactation day 2. However, the molecular underpinnings of these defects are not understood. Here, we used lactating C57BL/6J(lm/lm) (ZnT4-null) mice to explore the consequences of a ZnT4-null phenotype on mammary gland function during early lactation. Lactating C57BL/6J(lm/lm) mice had significantly fewer, smaller, and collapsed alveoli comprising swollen, lipid-filled MECs during early lactation. These defects were associated with decreased Akt expression and STAT5 activation, indicative of defects in MEC secretion. In addition, increased expression of ZnT2, TNF-α, and cleaved e-cadherin concomitant with increased activation of STAT3 implicated the loss of ZnT4 in precocious activation of involution. Collectively, our study indicates that the loss of ZnT4 has profound consequences on MEC secretion and may promote tissue remodeling in the mammary gland during early lactation. PMID:26538236

  16. Acute intermittent hypoxia-induced expression of brain-derived neurotrophic factor is disrupted in the brainstem of methyl-CpG-binding protein 2 null mice.

    PubMed

    Vermehren-Schmaedick, A; Jenkins, V K; Knopp, S J; Balkowiec, A; Bissonnette, J M

    2012-03-29

    Rett syndrome is a neurodevelopmental disorder caused by loss-of-function mutations in the gene encoding the transcription factor methyl-CpG-binding protein 2 (MeCP2). One of its targets is the gene encoding brain-derived neurotrophic factor (bdnf). In vitro studies using cultured neurons have produced conflicting results with respect to the role of MeCP2 in BDNF expression. Acute intermittent hypoxia (AIH) induces plasticity in the respiratory system characterized by long-term facilitation of phrenic nerve amplitude. This paradigm induces an increase in BDNF protein. We hypothesized that AIH leads to augmentation of BDNF transcription in respiratory-related areas of the brainstem and that MeCP2 is necessary for this process. Wild-type and mecp2 null (mecp2(-/y)) mice were subjected to three 5-min episodes of exposure to 8% O(2)/4% CO(2)/88% N(2), delivered at 5-min intervals. Normoxia control wild-type and mecp2 null mice were exposed to room air for the total length of time, that is, 30 min. Following a recovery in room air, the pons and medulla were rapidly removed. Expression of BDNF protein and transcripts were determined by ELISA and quantitative PCR, respectively. AIH induced a significant increase in BDNF protein in the pons and medulla, and in mRNA transcript levels in the pons of wild-type animals. In contrast, there were no significant changes in either BDNF protein or transcripts in the pons or medulla of mice lacking MeCP2. The results indicate that MeCP2 is required for regulation of BDNF expression by acute intermittent hypoxia in vivo. PMID:22297041

  17. Acute intermittent hypoxia-induced expression of Brain-Derived Neurotrophic Factor is disrupted in the brainstem of mecp2 null mice

    PubMed Central

    Vermehren-Schmaedick, Anke; Jenkins, Victoria K.; Knopp, Sharon J.; Balkowiec, Agnieszka; Bissonnette, John M.

    2012-01-01

    Rett syndrome is a neurodevelopmental disorder caused by loss of function mutations in the gene encoding the transcription factor methyl-CpG-binding protein 2 (MeCP2). One of its targets is the gene encoding brain-derived neurotrophic factor (bdnf). In vitro studies using cultured neurons have produced conflicting results with respect to the role of MeCP2 in BDNF expression. Acute intermittent hypoxia (AIH) induces plasticity in the respiratory system characterized by long-term facilitation of phrenic nerve amplitude. This paradigm induces an increase in BDNF protein. We hypothesized that AIH leads to augmentation of BDNF transcription in respiratory-related areas of the brainstem and that MeCP2 is necessary for this process. Wild-type and mecp2 null (mecp2−/y) mice were subjected to three 5-min episodes of exposure to 8% O2/4% CO2/88% N2, delivered at 5-min intervals. Normoxia control wild-type and mecp2 null mice were exposed to room air for the total length of time, i.e. 30 min. Following a recovery in room air, the pons and medulla were rapidly removed. Expression of BDNF protein and transcripts were determined by ELISA and quantitative PCR, respectively. AIH induced a significant increase in BDNF protein in the pons and medulla, and in mRNA transcript levels in the pons of wild-type animals. In contrast, there were no significant changes in either BDNF protein or transcripts in the pons or medulla of mice lacking Mecp2. The results indicate that Mecp2 is required for regulation of BDNF expression by acute intermittent hypoxia in vivo. PMID:22297041

  18. Wild-type and IL10-null mice have differential colonic epithelial gene expression responses to dietary supplementation with synbiotic Bifidobacterium animalis subspecies lactis and inulin.

    PubMed

    Kuo, Shiu-Ming; Chan, Wan-Chun; Hu, Zihua

    2014-03-01

    Prebiotic plus probiotic (synbiotic) supplementations promote fermentation and have shown anti-inflammatory activity in colonic epithelium. However, in many instances, patients with inflammatory bowel disease (IBD) have demonstrated adverse effects after prebiotic supplementation at a dose well tolerated by normal individuals. To test the hypothesis that the host inflammation affects the colonic epithelial response to increased fermentation, the gene expression of colonic epithelium was analyzed. In a 1-way experimental design to test the effect of supplements in wild-type mice using the standard diet formulated by the American Institute of Nutrition (AIN-93G) as the control diet, fermentable fiber inulin (5%) in the absence or presence of the probiotic Bifidobacterium animalis subspecies lactis (Bb12) (10(8) CFU/kg diet) showed limited effects on gene expression as determined by whole-genome microarray. Bb12 supplementation alone was known not to increase fermentation and here instead significantly upregulated genes in nucleic acid metabolic processes. The effects of the synbiotic diet were then determined in mice exposed to LPS-induced inflammation in a 2-way experimental design testing the effect of diet and LPS. The microarray and quantitative reverse transcription-polymerase chain reaction analyses on the wild-type mice revealed that LPS-induced changes in the colonic epithelium were 4- to 10-fold less in the synbiotic diet group compared with the control diet group. Unlike the wild-type mice, anti-inflammatory cytokine interleukin 10 (IL10)-null mice (susceptible to IBD) given the synbiotic diet, compared with those given the control diet, had 3- to 40-fold increased expression of inflammation-related genes such as Cxcl1 (chemokine C-X-C motif ligand 1) and S100a9 (S100 calcium binding protein A9) in the absence and presence of LPS exposure. These contrasting intestinal epithelial responses to increased fermentation in wild-type and IL10-null mice are similar

  19. Antibody Repertoires in Humanized NOD-scid-IL2Rγnull Mice and Human B Cells Reveals Human-Like Diversification and Tolerance Checkpoints in the Mouse

    PubMed Central

    Ippolito, Gregory C.; Hoi, Kam Hon; Reddy, Sai T.; Carroll, Sean M.; Ge, Xin; Rogosch, Tobias; Zemlin, Michael; Shultz, Leonard D.; Ellington, Andrew D.; VanDenBerg, Carla L.; Georgiou, George

    2012-01-01

    Immunodeficient mice reconstituted with human hematopoietic stem cells enable the in vivo study of human hematopoiesis. In particular, NOD-scid-IL2Rγnull engrafted mice have been shown to have reasonable levels of T and B cell repopulation and can mount T-cell dependent responses; however, antigen-specific B-cell responses in this model are generally poor. We explored whether developmental defects in the immunoglobulin gene repertoire might be partly responsible for the low level of antibody responses in this model. Roche 454 sequencing was used to obtain over 685,000 reads from cDNA encoding immunoglobulin heavy (IGH) and light (IGK and IGL) genes isolated from immature, naïve, or total splenic B cells in engrafted NOD-scid-IL2Rγnull mice, and compared with over 940,000 reads from peripheral B cells of two healthy volunteers. We find that while naïve B-cell repertoires in humanized mice are chiefly indistinguishable from those in human blood B cells, and display highly correlated patterns of immunoglobulin gene segment use, the complementarity-determining region H3 (CDR-H3) repertoires are nevertheless extremely diverse and are specific for each individual. Despite this diversity, preferential DH-JH pairings repeatedly occur within the CDR-H3 interval that are strikingly similar across all repertoires examined, implying a genetic constraint imposed on repertoire generation. Moreover, CDR-H3 length, charged amino-acid content, and hydropathy are indistinguishable between humans and humanized mice, with no evidence of global autoimmune signatures. Importantly, however, a statistically greater usage of the inherently autoreactive IGHV4-34 and IGKV4-1 genes was observed in the newly formed immature B cells relative to naïve B or total splenic B cells in the humanized mice, a finding consistent with the deletion of autoreactive B cells in humans. Overall, our results provide evidence that key features of the primary repertoire are shaped by genetic factors

  20. Long-Term Enrichment Enhances the Cognitive Behavior of the Aging Neurogranin Null Mice without Affecting Their Hippocampal LTP

    ERIC Educational Resources Information Center

    Huang, Freesia L.; Huang, Kuo-Ping; Boucheron, Catherine

    2007-01-01

    Neurogranin (Ng), a PKC substrate, is abundantly expressed in brain regions important for cognitive functions. Deletion of Ng caused severe deficits in spatial learning and LTP in the hippocampal CA1 region of mice. These Ng-/- mice also exhibit deficits in the amplification of their hippocampal signaling pathways critical for learning and memory.…

  1. Accumulation of xenotransplanted canine bone marrow cells in NOD/SCID/γc(null) mice with acute hepatitis induced by CCl4.

    PubMed

    Kato, Takashi; Hisasue, Masaharu; Segawa, Kazuhito; Fujimoto, Ayumi; Makiishi, Eri; Neo, Sakurako; Yasuno, Kyohei; Kobayashi, Ryosuke; Tsuchiya, Ryo

    2013-07-31

    Bone marrow cell infusion (BMI) has recently been suggested as an effective therapy for refractory liver disease; however, the efficiency of BMI using canine bone marrow cells (cBMCs) has not been reported. We evaluated the accumulation potential of cBMCs in a mouse model of acute liver failure. Acute hepatitis was induced by carbon tetrachloride (CCl4) treatment in NOD/SCID/γc(null)(NOG) mice and wild-type (WT) C57BL mice, and the characteristics of liver dysfunction and the degree of hepatic injury and regeneration were compared between the two mouse models. Next, female CCl4-treated NOG mice were xenotransplanted with male PKH26-labeled cBMCs, and the potential of cBMCs to accumulate in injured liver tissue compartments was examined. Fluorescence microscopy was performed to histologically detect the infused cBMCs, and DNA polymerase chain reaction was performed for detection of the male Y chromosome (SRY gene) in the recipient female NOG mice. The number of PKH26-positive cBMCs transplanted in the liver tissue gradually increased in the NOG mice. The infused cBMCs were located in the necrotic area of the liver at an early stage after transplantation, and most had accumulated a week after transplantation. However, the therapeutic efficacy of the xenotransplantation remained unclear, because no significant differences were observed concerning the extent liver injury and regeneration between the cBMC-transplanted and saline control mice. These results suggest that cBMCs will specifically accumulate in injured liver tissue and that BMC transplantation may have the potential to repair liver deficiency. PMID:23411484

  2. Antioxidant/oxidant status and cardiac function in bradykinin B(1)- and B(2)-receptor null mice.

    PubMed

    Delemasure, S; Blaes, N; Richard, C; Couture, R; Bader, M; Dutartre, P; Girolami, J-P; Connat, J-L; Rochette, L

    2013-01-01

    Kinin-vasoactive peptides activate two G-protein-coupled receptors (R), B(1)R (inducible) and B(2)R (constitutive). Their complex role in cardiovascular diseases could be related to differential actions on oxidative stress. This study investigated impacts of B(1)R or B(2)R gene deletion in mice on the cardiac function and plasma antioxidant and oxidant status. Echocardiography-Doppler was performed in B(1)R (B(1)R(-/-)) and B(2)R (B(2)R(-/-)) deficient and wild type (WT) adult male mice. No functional alteration was observed in B(2)R(-/-) hearts. B(1)R(-/-) mice had significantly lowered fractional shortening and increased isovolumetric contraction time. The diastolic E and A waves velocity ratio was similar in all mice groups. Thus B(1)R(-/-) mice provide a model of moderate systolic dysfunction, whereas B(2)R(-/-) mice displayed a normal cardiac phenotype. Plasma antioxidant capacity (ORAC) was significantly decreased in both B(1)R(-/-) and B(2)R(-/-) mice whereas the vitamin C levels were decreased in B(2)R(-/-) mice only. Plasma ascorbyl free radical was significantly higher in B(1)R(-/-) compared to WT and B(2)R(-/-) mice. Therefore, the oxidative stress index, ascorbyl free radical to vitamin C ratio, was increased in both B(1)R(-/-) and B(2)R(-/-) mice. Hence, B(1)R and B(2)R deficiency are associated with increased oxidative stress, but there is a differential imbalance between free radical production and antioxidant defense. The interrelationship between the differential B(1)R and B(2)R roles in oxidative stress and cardiovascular diseases remain to be investigated. PMID:24020815

  3. The impact of agrin on the formation of orthogonal arrays of particles in cultured astrocytes from wild-type and agrin-null mice.

    PubMed

    Fallier-Becker, Petra; Sperveslage, Jan; Wolburg, Hartwig; Noell, Susan

    2011-01-01

    Astrocytic endfeet membranes are studded with aquaporin-4 (AQP4) containing orthogonal arrays of particles (OAP) which can be visualized exclusively by the freeze-fracturing method. They are predominantly expressed where the astroglial membrane is in contact with the superficial and perivascular basal lamina. This polarity seems to be essential for the integrity of the blood-brain barrier (BBB). The basal lamina containing many extracellular matrix (ECM) components such as collagen, laminin and heparansulfate proteoglycans like agrin is thought to influence this OAP-related polarity of astrocytes. Recently, we have shown that agrin, in particular the neuronal isoform A4B8, is capable of influencing the formation of OAPs in astrocytes when cultured in the presence of agrin-conditioned media. In this paper we wanted to investigate whether coating with exogenous agrin compared to coating with other ECM components would induce OAP formation in astrocytes of the agrin-null mouse. For this purpose, we cultured astrocytes from agrin-null and wild-type mice on agrin- or ECM-coated surfaces. Immunofluorescent cytochemical staining of AQP4 indicated a higher AQP4 expression level in cultures with agrin- or ECM-coated than in cultures with uncoated surfaces, whereas western blot analyses and PCR showed no differences. α-Dystroglycan is thought to be a potential receptor of agrin and was immunostained in wild-type as well as in agrin-null astrocytes. In freeze-fracture replicas, we observed an increase in OAP density in astrocytes when growing on agrin- and ECM-coatings. These results concurred with other experiments in which changes in volume were measured following hypotonic stress, which supported the positive influence of exogenous agrin on AQP4 insertion into the membrane, on OAP formation and on water transport. PMID:20920487

  4. Coordinated Regulation of Hepatic Phase I and II Drug-Metabolizing Genes and Transporters using AhR-, CAR-, PXR-, PPARα-, and Nrf2-Null Mice

    PubMed Central

    Aleksunes, Lauren M.

    2012-01-01

    The transcription factors aryl hydrocarbon receptor (AhR), constitutive androstane receptor (CAR), pregnane X receptor (PXR), peroxisome proliferator-activated receptor α (PPARα), and nuclear factor erythroid 2-related factor 2 (Nrf2) regulate genes encoding drug-metabolizing enzymes and transporters in livers of mice after chemical activation. However, the specificity of their transcriptional regulation has not been determined systematically in vivo. The purpose of this study was to identify genes encoding drug-metabolizing enzymes and transporters altered by chemical activators in a transcription factor-dependent manner using wild-type and transcription factor-null mice. Chemical activators were administered intraperitoneally to mice once daily for 4 days. Livers were collected 24 h after the final dose, and total RNA was isolated for mRNA quantification of cytochromes P450, NAD(P)H quinone oxidoreductase 1 (Nqo1), aldehyde dehydrogenases (Aldhs), glutathione transferases (Gsts), sulfotransferases (Sults), UDP-glucuronosyltransferases (Ugts), organic anion-transporting polypeptides (Oatps), and multidrug resistance-associated proteins (Mrps). Pharmacological activation of each transcription factor leads to mRNA induction of drug metabolic and transport genes in livers of male and female wild-type mice, but no change in null mice: AhR (Cyp1a2, Nqo1, Aldh7a1, Ugt1a1, Ugt1a6, Ugt1a9, Ugt2b35, Sult5a1, Gstm3, and Mrp4), CAR (Cyp2b10, Aldh1a1, Aldh1a7, Ugt1a1, Ugt2b34, Sult1e1, Sult3a1, Sult5a1, Papps2, Gstt1, Gsta1, Gsta4, Gstm1–4, and Mrp2–4), PXR (Cyp3a11, Ugt1a1, Ugt1a5, Ugt1a9, Gsta1, Gstm1–m3, Oatp1a4, and Mrp3), PPARα (Cyp4a14, Aldh1a1, mGst3, Gstm4, and Mrp4), and Nrf2 (Nqo1, Aldh1a1, Gsta1, Gsta4, Gstm1–m4, mGst3, and Mrp3–4). Taken together, these data reveal transcription factor specificity and overlap in regulating hepatic drug disposition genes by chemical activators. Coordinated regulation of phase I, phase II, and transport genes by

  5. Rescue of the skeletal phenotype in CasR-deficient mice by transfer onto the Gcm2 null background

    PubMed Central

    Tu, Qisheng; Pi, Min; Karsenty, Gerard; Simpson, Leigh; Liu, Shiguang; Quarles, L. Darryl

    2003-01-01

    To understand the role of the calcium-sensing receptor (CasR) in the skeleton, we used a genetic approach to ablate parathyroid glands and remove the confounding effects of elevated parathyroid hormone (PTH) in CasR-deficient mice. CasR deficiency was transferred onto the glial cells missing 2–deficient (Gcm2-deficient) background by intercrossing CasR- and Gcm2-deficient mice. Superimposed Gcm2 deficiency rescued the perinatal lethality in CasR-deficient mice in association with ablation of the parathyroid glands and correction of the severe hyperparathyroidism. In addition, the double homozygous CasR- and Gcm2-deficient mice demonstrated healing of the abnormal mineralization of cartilage and bone associated with CasR deficiency, indicating that rickets and osteomalacia in CasR-deficient mice are not due to an independent function of CasR in bone and cartilage but to the effect of severe hyperparathyroidism in the neonate. Analysis of the skeleton of 6-week-old homozygous CasR- and Gcm2-deficient mice also failed to identify any essential, nonredundant role for CasR in regulating chondrogenesis or osteogenesis, but further studies are needed to establish the function of CasR in the skeleton. In contrast, concomitant Gcm2 and CasR deficiency failed to rescue the hypocalciuria in CasR-deficient mice, consistent with direct regulation of urinary calcium excretion by CasR in the kidney. Double Gcm2- and CasR-deficient mice provide an important model for evaluating the extraparathyroid functions of CasR. PMID:12671052

  6. Podocyte-Specific VEGF-A Gain of Function Induces Nodular Glomerulosclerosis in eNOS Null Mice

    PubMed Central

    Veron, Delma; Aggarwal, Pardeep K.; Velazquez, Heino; Kashgarian, Michael; Moeckel, Gilbert

    2014-01-01

    VEGF-A and nitric oxide are essential for glomerular filtration barrier homeostasis and are dysregulated in diabetic nephropathy. Here, we examined the effect of excess podocyte VEGF-A on the renal phenotype of endothelial nitric oxide synthase (eNOS) knockout mice. Podocyte-specific VEGF164 gain of function in eNOS−/− mice resulted in nodular glomerulosclerosis, mesangiolysis, microaneurysms, and arteriolar hyalinosis associated with massive proteinuria and renal failure in the absence of diabetic milieu or hypertension. In contrast, podocyte-specific VEGF164 gain of function in wild-type mice resulted in less pronounced albuminuria and increased creatinine clearance. Transmission electron microscopy revealed glomerular basement membrane thickening and podocyte effacement in eNOS−/− mice with podocyte-specific VEGF164 gain of function. Furthermore, glomerular nodules overexpressed collagen IV and laminin extensively. Biotin-switch and proximity ligation assays demonstrated that podocyte-specific VEGF164 gain of function decreased glomerular S-nitrosylation of laminin in eNOS−/− mice. In addition, treatment with VEGF-A decreased S-nitrosylated laminin in cultured podocytes. Collectively, these data indicate that excess glomerular VEGF-A and eNOS deficiency is necessary and sufficient to induce Kimmelstiel-Wilson–like nodular glomerulosclerosis in mice through a process that involves deposition of laminin and collagen IV and de-nitrosylation of laminin. PMID:24578128

  7. Transcriptional profile reveals altered hepatic lipid and cholesterol metabolism in hyposulfatemic NaS1 null mice.

    PubMed

    Dawson, Paul Anthony; Gardiner, Brooke; Grimmond, Sean; Markovich, Daniel

    2006-07-12

    Sulfate plays an essential role in human growth and development, and its circulating levels are maintained by the renal Na+-SO42- cotransporter, NaS1. We previously generated a NaS1 knockout (Nas1-/-) mouse, an animal model for hyposulfatemia, that exhibits reduced growth and liver abnormalities including hepatomegaly. In this study, we investigated the hepatic gene expression profile of Nas1-/- mice using oligonucleotide microarrays. The mRNA expression levels of 92 genes with known functional roles in metabolism, cell signaling, cell defense, immune response, cell structure, transcription, or protein synthesis were increased (n = 51) or decreased (n = 41) in Nas1-/- mice when compared with Nas1+/+ mice. The most upregulated transcript levels in Nas1-/- mice were found for the sulfotransferase genes, Sult3a1 (approximately 500% increase) and Sult2a2 (100% increase), whereas the metallothionein-1 gene, Mt1, was among the most downregulated genes (70% decrease). Several genes involved in lipid and cholesterol metabolism, including Scd1, Acly, Gpam, Elov16, Acsl5, Mvd, Insig1, and Apoa4, were found to be upregulated (> or = 30% increase) in Nas1-/- mice. In addition, Nas1-/- mice exhibited increased levels of hepatic lipid (approximately 16% increase), serum cholesterol (approximately 20% increase), and low-density lipoprotein (approximately 100% increase) and reduced hepatic glycogen (approximately 50% decrease) levels. In conclusion, these data suggest an altered lipid and cholesterol metabolism in the hyposulfatemic Nas1-/- mouse and provide new insights into the metabolic state of the liver in Nas1-/- mice. PMID:16621889

  8. Ketogenic diet exposure during the juvenile period increases social behaviors and forebrain neural activation in adult Engrailed 2 null mice.

    PubMed

    Verpeut, Jessica L; DiCicco-Bloom, Emanuel; Bello, Nicholas T

    2016-07-01

    Prolonged consumption of ketogenic diets (KD) has reported neuroprotective benefits. Several studies suggest KD interventions could be useful in the management of neurological and developmental disorders. Alterations in the Engrailed (En) genes, specifically Engrailed 2 (En2), have neurodevelopmental consequences and produce autism-related behaviors. The following studies used En2 knockout (KO; En2(-/-)), and wild-type (WT; En2(+/+)), male mice fed either KD (80% fat, 0.1% carbohydrates) or control diet (CD; 10% fat, 70% carbohydrates). The objective was to determine whether a KD fed from weaning at postnatal day (PND) 21 to adulthood (PND 60) would alter brain monoamines concentrations, previously found dysregulated, and improve social outcomes. In WT animals, there was an increase in hypothalamic norepinephrine content in the KD-fed group. However, regional monoamines were not altered in KO mice in KD-fed compared with CD-fed group. In order to determine the effects of juvenile exposure to KD in mice with normal blood ketone levels, separate experiments were conducted in mice removed from the KD or CD and fed standard chow for 2days (PND 62). In a three-chamber social test with a novel mouse, KO mice previously exposed to the KD displayed similar social and self-grooming behaviors compared with the WT group. Groups previously exposed to a KD, regardless of genotype, had more c-Fos-positive cells in the cingulate cortex, lateral septal nuclei, and anterior bed nucleus of the stria terminalis. In the novel object condition, KO mice previously exposed to KD had similar behavioral responses and pattern of c-Fos immunoreactivity compared with the WT group. Thus, juvenile exposure to KD resulted in short-term consequences of improving social interactions and appropriate exploratory behaviors in a mouse model that displays autism-related behaviors. Such findings further our understanding of metabolic-based therapies for neurological and developmental disorders. PMID

  9. Axonopathy in the Central Nervous System Is the Hallmark of Mice with a Novel Intragenic Null Mutation of Dystonin.

    PubMed

    Seehusen, Frauke; Kiel, Kirsten; Jottini, Stefano; Wohlsein, Peter; Habierski, Andre; Seibel, Katharina; Vogel, Tanja; Urlaub, Henning; Kollmar, Martin; Baumgärtner, Wolfgang; Teichmann, Ulrike

    2016-09-01

    Dystonia musculorum is a neurodegenerative disorder caused by a mutation in the dystonin gene. It has been described in mice and humans where it is called hereditary sensory autonomic neuropathy. Mutated mice show severe movement disorders and die at the age of 3-4 weeks. This study describes the discovery and molecular, clinical, as well as pathological characterization of a new spontaneously occurring mutation in the dystonin gene in C57BL/6N mice. The mutation represents a 40-kb intragenic deletion allele of the dystonin gene on chromosome 1 with exactly defined deletion borders. It was demonstrated by Western blot, mass spectrometry, and immunohistology that mice with a homozygous mutation were entirely devoid of the dystonin protein. Pathomorphological lesions were restricted to the brain stem and spinal cord and consisted of swollen, argyrophilic axons and dilated myelin sheaths in the white matter and, less frequently, total chromatolysis of neurons in the gray matter. Axonal damage was detected by amyloid precursor protein and nonphosphorylated neurofilament immunohistology. Axonopathy in the central nervous system (CNS) represents the hallmark of this disease. Mice with the dystonin mutation also showed suppurative inflammation in the respiratory tract, presumably due to brain stem lesion-associated food aspiration, whereas skeletal muscles showed no pathomorphological changes. This study describes a novel mutation in the dystonin gene in mice leading to axonopathy in the CNS. In further studies, this model may provide new insights into the pathogenesis of neurodegenerative diseases and may elucidate the complex interactions of dystonin with various other cellular proteins especially in the CNS. PMID:27401753

  10. Engraftment of peripheral blood mononuclear cells from human T-lymphotropic virus type 1 carriers in NOD/SCID/gammac(null) (NOG) mice.

    PubMed

    Takajo, Ichiro; Umeki, Kazumi; Morishita, Kazuhiro; Yamamoto, Ikuo; Kubuki, Yoko; Hatakeyama, Kinta; Kataoka, Hiroaki; Okayama, Akihiko

    2007-11-15

    The transmission of human T-lymphotropic virus Type 1 (HTLV-1) occurs mainly via breast-feeding, sexual intercourse and blood transfusions. After transmission, the HTLV-1 infection is predominantly maintained by cell-to-cell infection and clonal expansion; however, the details have not yet been clarified. To investigate how HTLV-1 infected cells act in an environment without an effective immune reaction, peripheral blood mononuclear cells (PBMCs) from asymptomatic HTLV-1 carriers were inoculated into nonobese diabetic/severe combined immunodeficient (NOD/SCID)/gammac(null) (NOG) mice, which have immunological dysfunctions of T- and B-lymphocytes and NK cells. Human mononuclear cells including both CD4+ and CD8+ T cells were found to have infiltrated into various organs, including the liver, kidney, spleen and lung, when the mice were sacrificed 1 month after inoculation. The copy numbers of HTLV-1 provirus detected in the tissue-infiltrating human cells were much higher than those in the original PBMCs from the carriers. The expression of HTLV-1 mRNA was demonstrated in the tissue-infiltrating cells by reverse transcriptase-polymerase chain reaction. Inverse-long polymerase chain reaction showed that the pattern of HTLV-1 proviral integration was different from that of the original carrier and that it varied among NOG mice inoculated with PBMCs from the same carrier. These results suggest the selective proliferation of particular clones of HTLV-1 infected cells in NOG mice. Alternatively, transmission and new integration of HTLV-1 from infected cells to noninfected cells might have occurred in an environment without an effective immune reaction. The NOG mouse is considered a good animal model for the patho-physiological study of HTLV-1 infection with immunodeficiency. PMID:17657714

  11. Slc10a2-null mice uncover colon cancer-promoting actions of endogenous fecal bile acids.

    PubMed

    Raufman, Jean-Pierre; Dawson, Paul A; Rao, Anuradha; Drachenberg, Cinthia B; Heath, Jonathon; Shang, Aaron C; Hu, Shien; Zhan, Min; Polli, James E; Cheng, Kunrong

    2015-10-01

    Although epidemiological evidence in humans and bile acid feeding studies in rodents implicate bile acids as tumor promoters, the role of endogenous bile acids in colon carcinogenesis remains unclear. In this study, we exploited mice deficient in the ileal apical sodium-dependent bile acid transporter (ASBT, encoded by SLC10A2) in whom fecal bile acid excretion is augmented more than 10-fold. Wild-type and Asbt-deficient (Slc10a2 (-/-) ) male mice were treated with azoxymethane (AOM) alone to examine the development of aberrant crypt foci, the earliest histological marker of colon neoplasia and a combination of AOM and dextran sulfate sodium to induce colon tumor formation. Asbt-deficient mice exhibited a 54% increase in aberrant crypt foci, and 70 and 59% increases in colon tumor number and size, respectively. Compared to littermate controls, Asbt-deficient mice had a striking, 2-fold increase in the number of colon adenocarcinomas. Consistent with previous studies demonstrating a role for muscarinic and epidermal growth factor receptor signaling in bile acid-induced colon neoplasia, increasing bile acid malabsorption was associated with M3 muscarinic and epidermal growth factor receptor expression, and activation of extracellular signal-related kinase, a key post-receptor signaling molecule. PMID:26210740

  12. Inhibition of development of laser-induced choroidal neovascularization with suppression of infiltration of macrophages in Smad3-null mice.

    PubMed

    Iwanishi, Hiroki; Fujita, Norihito; Tomoyose, Katsuo; Okada, Yuka; Yamanaka, Osamu; Flanders, Kathleen C; Saika, Shizuya

    2016-06-01

    We evaluated the effects of the loss of Smad3 on the development of experimental argon laser-induced choroidal neovascularization (CNV) in mice. An in vitro angiogenesis model was also used to examine the role of transforming growth factor-β1 (TGFβ1)/Smad3 signaling in vessel-like tube formation by human umbilical vein endothelial cells (HUVECs). CNV was induced in eyes of 8-12-week-old B6.129-background Smad3-deficient (KO) mice (n=47) and wild-type (WT) mice (n=47) by argon laser irradiation. Results showed that the size of the CNV induced was significantly smaller in KO mice as compared with WT mice at day 14 as revealed by high-resolution angiography with fluorescein isothiocyanate-dextran. Immunohistochemistry and real-time reverse transcription-polymerase chain reaction of RNA extracted from laser-irradiated choroidal tissues were conducted on specimens at specific timepoints. Invasion of macrophages (F4/80+), but not neutrophils (myeloperoxidase+), and appearance of myofibroblasts (α-smooth muscle actin+) were suppressed in laser-irradiated KO tissues. mRNA expression of inflammation-related factors, that is, vascular endothelial growth factor (VEGF), macrophage-chemoattractant protein-1 (MCP-1), interleukin-6 (IL-6) and TGFβ1 in choroidal tissues was suppressed by the loss of Smad3. We then examined the effects of adding a Smad3 inhibitor, SIS3, or an ALK5 inhibitor, SB431542, on tube formation promoted by TGFβ1 or VEGF in HUVECs cocultured with fibroblast feeder. Further addition of SIS3 or SB431542 augmented vessel-like tube formation by HUVECs in the presence of TGFβ1 or VEGF. In conclusion, lack of Smad3 attenuated the growth of laser-induced CNV with suppression of inflammation by macrophages in mice. Because blocking TGFβ1/Smad3 signal stimulated the activity of angiogenesis of HUVECs in vitro, the reduction of CNV in vivo in KO mice is attributed to a decrease in growth factor levels in the tissue by the loss of Smad3. PMID:26950486

  13. Glutamate Cysteine Ligase Modifier Subunit (Gclm) Null Mice Have Increased Ovarian Oxidative Stress and Accelerated Age-Related Ovarian Failure.

    PubMed

    Lim, Jinhwan; Nakamura, Brooke N; Mohar, Isaac; Kavanagh, Terrance J; Luderer, Ulrike

    2015-09-01

    Glutathione (GSH) is the one of the most abundant intracellular antioxidants. Mice lacking the modifier subunit of glutamate cysteine ligase (Gclm), the rate-limiting enzyme in GSH synthesis, have decreased GSH. Our prior work showed that GSH plays antiapoptotic roles in ovarian follicles. We hypothesized that Gclm(-/-) mice have accelerated ovarian aging due to ovarian oxidative stress. We found significantly decreased ovarian GSH concentrations and oxidized GSH/oxidized glutathione redox potential in Gclm(-/-) vs Gclm(+/+) ovaries. Prepubertal Gclm(-/-) and Gclm(+/+) mice had similar numbers of ovarian follicles, and as expected, the total number of ovarian follicles declined with age in both genotypes. However, the rate of decline in follicles was significantly more rapid in Gclm(-/-) mice, and this was driven by accelerated declines in primordial follicles, which constitute the ovarian reserve. We found significantly increased 4-hydroxynonenal immunostaining (oxidative lipid damage marker) and significantly increased nitrotyrosine immunostaining (oxidative protein damage marker) in prepubertal and adult Gclm(-/-) ovaries compared with controls. The percentage of small ovarian follicles with increased granulosa cell proliferation was significantly higher in prepubertal and 2-month-old Gclm(-/-) vs Gclm(+/+) ovaries, indicating accelerated recruitment of primordial follicles into the growing pool. The percentages of growing follicles with apoptotic granulosa cells were increased in young adult ovaries. Our results demonstrate increased ovarian oxidative stress and oxidative damage in young Gclm(-/-) mice, associated with an accelerated decline in ovarian follicles that appears to be mediated by increased recruitment of follicles into the growing pool, followed by apoptosis at later stages of follicular development. PMID:26083875

  14. Tracking human multiple myeloma xenografts in NOD-Rag-1/IL-2 receptor gamma chain-null mice with the novel biomarker AKAP-4

    PubMed Central

    2011-01-01

    Background Multiple myeloma (MM) is a fatal malignancy ranking second in prevalence among hematological tumors. Continuous efforts are being made to develop innovative and more effective treatments. The preclinical evaluation of new therapies relies on the use of murine models of the disease. Methods Here we describe a new MM animal model in NOD-Rag1null IL2rgnull (NRG) mice that supports the engraftment of cell lines and primary MM cells that can be tracked with the tumor antigen, AKAP-4. Results Human MM cell lines, U266 and H929, and primary MM cells were successfully engrafted in NRG mice after intravenous administration, and were found in the bone marrow, blood and spleen of tumor-challenged animals. The AKAP-4 expression pattern was similar to that of known MM markers, such as paraproteins, CD38 and CD45. Conclusions We developed for the first time a murine model allowing for the growth of both MM cell lines and primary cells in multifocal sites, thus mimicking the disease seen in patients. Additionally, we validated the use of AKAP-4 antigen to track tumor growth in vivo and to specifically identify MM cells in mouse tissues. We expect that our model will significantly improve the pre-clinical evaluation of new anti-myeloma therapies. PMID:21923911

  15. Incretin Receptor Null Mice Reveal Key Role of GLP-1 but Not GIP in Pancreatic Beta Cell Adaptation to Pregnancy

    PubMed Central

    Moffett, R. Charlotte; Vasu, Srividya; Thorens, Bernard; Drucker, Daniel J.; Flatt, Peter R.

    2014-01-01

    Islet adaptations to pregnancy were explored in C57BL6/J mice lacking functional receptors for glucagon-like peptide 1 (GLP-1) and gastric inhibitory polypeptide (GIP). Pregnant wild type mice and GIPRKO mice exhibited marked increases in islet and beta cell area, numbers of medium/large sized islets, with positive effects on Ki67/Tunel ratio favouring beta cell growth and enhanced pancreatic insulin content. Alpha cell area and glucagon content were unchanged but prohormone convertases PC2 and PC1/3 together with significant amounts of GLP-1 and GIP were detected in alpha cells. Knockout of GLP-1R abolished these islet adaptations and paradoxically decreased pancreatic insulin, GLP-1 and GIP. This was associated with abolition of normal pregnancy-induced increases in plasma GIP, L-cell numbers, and intestinal GIP and GLP-1 stores. These data indicate that GLP-1 but not GIP is a key mediator of beta cell mass expansion and related adaptations in pregnancy, triggered in part by generation of intra-islet GLP-1. PMID:24927416

  16. Distinct Luminal-Type Mammary Carcinomas Arise from Orthotopic Trp53-Null Mammary Transplantation of Juvenile versus Adult Mice

    SciTech Connect

    Nguyen, David H.; Ouyang, Haoxu; Mao, Jian-Hua; Hlatky, Lynn; Barcellos-Hoff, M. H.

    2014-12-01

    Age and physiologic status, such as menopause, are risk factors for breast cancer. Less clear is what factors influence the diversity of breast cancer. In this study, we investigated the effect of host age on the distribution of tumor subtypes in mouse mammary chimera consisting of wild-type hosts and Trp53 nullizygous epithelium, which undergoes a high rate of neoplastic transformation. Wild-type mammary glands cleared of endogenous epithelium at 3 weeks of age were subsequently transplanted during puberty (5 weeks) or at maturation (10 weeks) with syngeneic Trp53-null mammary tissue fragments and monitored for one year. Tumors arose sooner from adult hosts (AH) compared with juvenile hosts (JH). However, compared with AH tumors, JH tumors grew several times faster, were more perfused, exhibited a two-fold higher mitotic index, and were more highly positive for insulin-like growth factor receptor phosphorylation. Most tumors in each setting were estrogen receptor (ER)-positive (80% JH vs. 70% AH), but JH tumors were significantly more ER-immunoreactive (P = 0.0001) than AH tumors. A differential expression signature (JvA) of juvenile versus adult tumors revealed a luminal transcriptional program. Centroids of the human homologs of JvA genes showed that JH tumors were more like luminal A tumors and AH tumors were more like luminal B tumors. Hierarchical clustering with the JvA human ortholog gene list segregated luminal A and luminal B breast cancers across datasets. Lastly, these data support the notion that age-associated host physiology greatly influences the intrinsic subtype of breast cancer.

  17. Distinct Luminal-Type Mammary Carcinomas Arise from Orthotopic Trp53-Null Mammary Transplantation of Juvenile versus Adult Mice

    DOE PAGESBeta

    Nguyen, David H.; Ouyang, Haoxu; Mao, Jian-Hua; Hlatky, Lynn; Barcellos-Hoff, M. H.

    2014-12-01

    Age and physiologic status, such as menopause, are risk factors for breast cancer. Less clear is what factors influence the diversity of breast cancer. In this study, we investigated the effect of host age on the distribution of tumor subtypes in mouse mammary chimera consisting of wild-type hosts and Trp53 nullizygous epithelium, which undergoes a high rate of neoplastic transformation. Wild-type mammary glands cleared of endogenous epithelium at 3 weeks of age were subsequently transplanted during puberty (5 weeks) or at maturation (10 weeks) with syngeneic Trp53-null mammary tissue fragments and monitored for one year. Tumors arose sooner from adultmore » hosts (AH) compared with juvenile hosts (JH). However, compared with AH tumors, JH tumors grew several times faster, were more perfused, exhibited a two-fold higher mitotic index, and were more highly positive for insulin-like growth factor receptor phosphorylation. Most tumors in each setting were estrogen receptor (ER)-positive (80% JH vs. 70% AH), but JH tumors were significantly more ER-immunoreactive (P = 0.0001) than AH tumors. A differential expression signature (JvA) of juvenile versus adult tumors revealed a luminal transcriptional program. Centroids of the human homologs of JvA genes showed that JH tumors were more like luminal A tumors and AH tumors were more like luminal B tumors. Hierarchical clustering with the JvA human ortholog gene list segregated luminal A and luminal B breast cancers across datasets. Lastly, these data support the notion that age-associated host physiology greatly influences the intrinsic subtype of breast cancer.« less

  18. Highly efficient in vivo delivery of PMO into regenerating myotubes and rescue in laminin-α2 chain-null congenital muscular dystrophy mice.

    PubMed

    Aoki, Yoshitsugu; Nagata, Tetsuya; Yokota, Toshifumi; Nakamura, Akinori; Wood, Matthew J A; Partridge, Terence; Takeda, Shin'ichi

    2013-12-15

    Phosphorodiamidate morpholino oligomer (PMO)-mediated exon skipping is among the more promising approaches to the treatment of several neuromuscular disorders including Duchenne muscular dystrophy. The main weakness of this approach arises from the low efficiency and sporadic nature of the delivery of charge-neutral PMO into muscle fibers, the mechanism of which is unknown. In this study, to test our hypothesis that muscle fibers take up PMO more efficiently during myotube formation, we induced synchronous muscle regeneration by injection of cardiotoxin into the tibialis anterior muscle of Dmd exon 52-deficient mdx52 and wild-type mice. Interestingly, by in situ hybridization, we detected PMO mainly in embryonic myosin heavy chain-positive regenerating fibers. In addition, we showed that PMO or 2'-O-methyl phosphorothioate is taken up efficiently into C2C12 myotubes when transfected 24-72 h after the induction of differentiation but is poorly taken up into undifferentiated C2C12 myoblasts suggesting efficient uptake of PMO in the early stages of C2C12 myotube formation. Next, we tested the therapeutic potential of PMO for laminin-α2 chain-null dy(3K)/dy(3K) mice: a model of merosin-deficient congenital muscular dystrophy (MDC1A) with active muscle regeneration. We confirmed the recovery of laminin-α2 chain and slightly prolonged life span following skipping of the mutated exon 4 in dy(3K)/dy(3K) mice. These findings support the idea that PMO entry into fibers is dependent on a developmental stage in myogenesis rather than on dystrophinless muscle membranes and provide a platform for developing PMO-mediated therapies for a variety of muscular disorders, such as MDC1A, that involve active muscle regeneration. PMID:23882132

  19. Aortic cholesterol accumulation correlates with systemic inflammation but not hepatic and gonadal adipose tissue inflammation in low-density lipoprotein receptor null mice.

    PubMed

    Wang, Shu; Miller, Bradley; Matthan, Nirupa R; Goktas, Zeynep; Wu, Dayong; Reed, Debra B; Yin, Xiangling; Grammas, Paula; Moustaid-Moussa, Naima; Shen, Chwan-Li; Lichtenstein, Alice H

    2013-12-01

    Inflammation is a major contributor to the development of atherosclerotic plaque, yet the involvement of liver and visceral adipose tissue inflammatory status in atherosclerotic lesion development has yet to be fully elucidated. We hypothesized that an atherogenic diet would increase inflammatory response and lipid accumulation in the liver and gonadal adipose tissue (GAT) and would correlate with systemic inflammation and aortic lesion formation in low-density lipoprotein (LDL) receptor null (LDLr-/-) mice. For 32 weeks, LDLr-/- mice (n = 10/group) were fed either an atherogenic (high saturated fat and cholesterol) or control (low fat and cholesterol) diet. Hepatic and GAT lipid content and expression of inflammatory factors were measured using standard procedures. Compared with the control diet, the atherogenic diet significantly increased hepatic triglyceride and total cholesterol (TC), primarily esterified cholesterol, and GAT triglyceride content. These changes were accompanied by increased expression of acyl-CoA synthetase long-chain family member 5, CD36, ATP-binding cassette, subfamily A, member 1 and scavenger receptor B class 1, and they decreased the expression of cytochrome P450, family 7 and subfamily a, polypeptide 1 in GAT. Aortic TC content was positively associated with hepatic TC, triglyceride, and GAT triglyceride contents as well as plasma interleukin 6 and monocyte chemoattractant protein-1 concentrations. Although when compared with the control diet, the atherogenic diet increased hepatic tumor necrosis factor α production, they were not associated with aortic TC content. These data suggest that the LDLr-/- mice responded to the atherogenic diet by increasing lipid accumulation in the liver and GAT, which may have increased inflammatory response. Aortic TC content was positively associated with systemic inflammation but not hepatic and GAT inflammatory status. PMID:24267047

  20. Addition of aspirin to a fish oil-rich diet decreases inflammation and atherosclerosis in ApoE-null mice.

    PubMed

    Sorokin, Alexander V; Yang, Zhi-Hong; Vaisman, Boris L; Thacker, Seth; Yu, Zu-Xi; Sampson, Maureen; Serhan, Charles N; Remaley, Alan T

    2016-09-01

    Aspirin (ASA) is known to alter the production of potent inflammatory lipid mediators, but whether it interacts with omega-3 fatty acids (FAs) from fish oil to affect atherosclerosis has not been determined. The goal was to investigate the impact of a fish oil-enriched diet alone and in combination with ASA on the production of lipid mediators and atherosclerosis. ApoE(-/-) female mice were fed for 13weeks one of the four following diets: omega-3 FA deficient (OD), omega-3 FA rich (OR) (1.8g omega-3 FAs/kg·diet per day), omega-3 FA rich plus ASA (ORA) (0.1g ASA/kg·diet per day) or an omega-3 FA deficient plus ASA (ODA) with supplement levels equivalent to human doses. Plasma lipids, atherosclerosis, markers of inflammation, hepatic gene expression and aortic lipid mediators were determined. Hepatic omega-3 FAs were markedly higher in OR (9.9-fold) and ORA (7-fold) groups. Mice in both OR and ORA groups had 40% less plasma cholesterol in very low-density lipoprotein-cholesterol and low-density lipoprotein fractions, but aortic plaque area formation was only significantly lower in the ORA group (5.5%) compared to the OD group (2.5%). Plasma PCSK9 protein levels were approximately 70% lower in the OR and ORA groups. Proinflammatory aortic lipid mediators were 50%-70% lower in the ODA group than in the OD group and more than 50% lower in the ORA group. In summary, less aortic plaque lesions and aortic proinflammatory lipid mediators were observed in mice on the fish oil diet plus ASA vs. just the fish oil diet. PMID:27394692

  1. Disruption of NBS1 gene leads to early embryonic lethality in homozygous null mice and induces specific cancer in heterozygous mice

    SciTech Connect

    Kurimasa, Akihiro; Burma, Sandeep; Henrie, Melinda; Ouyang, Honghai; Osaki, Mitsuhiko; Ito, Hisao; Nagasawa, Hatsumi; Little, John B.; Oshimura, Mitsuo; Li, Gloria C.; Chen, David J.

    2002-04-15

    Nijmegen breakage syndrome (NBS) is a rare autosomal recessive chromosome instability syndrome characterized by microcephaly, growth retardation, immunodeficiency, and cancer predisposition, with cellular features similar to that of ataxia telangiectasia (AT). NBS results from mutations in the mammalian gene Nbs1 that codes for a 95-kDa protein called nibrin, NBS1, or p95. To establish an animal model for NBS, we attempted to generate NBS1 knockout mice. However, NBS1 gene knockouts were lethal at an early embryonic stage. NBS1 homozygous(-/-) blastocyst cells cultured in vitro showed retarded growth and subsequently underwent growth arrest within 5 days of culture. Apoptosis, assayed by TUNEL staining, was observed in NBSI homozygous(-/-) blastocyst cells cultured for four days. NBSI heterozygous(+/-) mice were normal, and exhibited no specific phenotype for at least one year. However, fibroblast cells from NBSI heterozygous(+/-) mice displayed an enhanced frequency of spontaneous transformation to anchorage-independent growth as compared to NBS1 wild-type(+/+) cells. Furthermore, heterozygous(+/-) mice exhibited a high incidence of hepatocellular carcinoma after one year compared to wild-type mice, even though no significant differences in the incidence of other tumors such as lung adenocarcinoma and lymphoma were observed. Taken together, these results strongly suggest that NBS1 heterozygosity and reduced NBSI expression induces formation of specific tumors in mice.

  2. Post-translationally Abnormal Collagens of Prolyl 3-Hydroxylase-2 Null Mice Offer a Pathobiological Mechanism for the High Myopia Linked to Human LEPREL1 Mutations*

    PubMed Central

    Hudson, David M.; Joeng, Kyu Sang; Werther, Rachel; Rajagopal, Abbhirami; Weis, MaryAnn; Lee, Brendan H.; Eyre, David R.

    2015-01-01

    Myopia, the leading cause of visual impairment worldwide, results from an increase in the axial length of the eyeball. Mutations in LEPREL1, the gene encoding prolyl 3-hydroxylase-2 (P3H2), have recently been identified in individuals with recessively inherited nonsyndromic severe myopia. P3H2 is a member of a family of genes that includes three isoenzymes of prolyl 3-hydroxylase (P3H), P3H1, P3H2, and P3H3. Fundamentally, it is understood that P3H1 is responsible for converting proline to 3-hydroxyproline. This limited additional knowledge also suggests that each isoenzyme has evolved different collagen sequence-preferred substrate specificities. In this study, differences in prolyl 3-hydroxylation were screened in eye tissues from P3h2-null (P3h2n/n) and wild-type mice to seek tissue-specific effects due the lack of P3H2 activity on post-translational collagen chemistry that could explain myopia. The mice were viable and had no gross musculoskeletal phenotypes. Tissues from sclera and cornea (type I collagen) and lens capsule (type IV collagen) were dissected from mouse eyes, and multiple sites of prolyl 3-hydroxylation were identified by mass spectrometry. The level of prolyl 3-hydroxylation at multiple substrate sites from type I collagen chains was high in sclera, similar to tendon. Almost every known site of prolyl 3-hydroxylation in types I and IV collagen from P3h2n/n mouse eye tissues was significantly under-hydroxylated compared with their wild-type littermates. We conclude that altered collagen prolyl 3-hydroxylation is caused by loss of P3H2. We hypothesize that this leads to structural abnormalities in multiple eye tissues, but particularly sclera, causing progressive myopia. PMID:25645914

  3. Generation of Aorta Transcript Atlases of Wild-Type and Apolipoprotein E-null Mice by Laser Capture Microdissection-Based mRNA Expression Microarrays.

    PubMed

    Yin, Changjun; Mohanta, Sarajo; Ma, Zhe; Weber, Christian; Hu, Desheng; Weih, Falk; Habenicht, Andreas

    2015-01-01

    Atherosclerosis is a transmural chronic inflammatory disease of medium and large arteries. Though it is well recognized that immune responses contribute to atherosclerosis, it remains unclear whether these responses are carried out in secondary lymphoid organs such as the spleen and lymph nodes and/or within the arterial wall. Arteries are composed of three major layers, i.e., the laminae intima, media, and adventitia. However, each of these layers may play different roles in arterial wall biology and atherogenesis. We identified well-structured artery tertiary lymphoid organs (ATLOs) in the abdominal aorta adventitia but not in the intima of aged apolipoprotein E-null (ApoE(-/-)) mice. These observations suggested that disease-associated immune responses are highly territorialized within the arterial wall and that the adventitia may play distinct and hitherto unrecognized roles. Here, we set out to apply laser capture microdissection (LCM) to dissect plaque, media, adventitia, and adjacent aorta-draining lymph nodes (LN) in aged ApoE(-/-) mice in attempts to establish the territoriality of atherosclerosis immune responses. Using whole-genome mRNA expression microarrays of arterial wall tissues, we constructed robust transcript atlases of wild-type and ApoE(-/-) mouse aortas. Data were deposited in the National Center for Biotechnology Information's gene expression omnibus (GEO) and are accessible to the public through the Internet. These transcript atlases are anticipated to prove valuable to address a wide scope of issues ranging from atherosclerosis immunity and inflammation to the role of single genes in regulating arterial wall remodeling. This chapter presents protocols for LCM of mouse aorta and microarray expression analysis from LCM-isolated aorta laminae. PMID:26445797

  4. The common missense mutation D489N in TRIM32 causing limb girdle muscular dystrophy 2H leads to loss of the mutated protein in knock-in mice resulting in a Trim32-null phenotype.

    PubMed

    Kudryashova, Elena; Struyk, Arie; Mokhonova, Ekaterina; Cannon, Stephen C; Spencer, Melissa J

    2011-10-15

    Mutations in tripartite motif protein 32 (TRIM32) are responsible for several hereditary disorders that include limb girdle muscular dystrophy type 2H (LGMD2H), sarcotubular myopathy (STM) and Bardet Biedl syndrome. Most LGMD2H mutations in TRIM32 are clustered in the NHL β-propeller domain at the C-terminus and are predicted to interfere with homodimerization. To get insight into TRIM32's role in the pathogenesis of LGMD2H and to create an accurate model of disease, we have generated a knock-in mouse (T32KI) carrying the c.1465G > A (p.D489N) mutation in murine Trim32 corresponding to the human LGMD2H/STM pathogenic mutation c.1459G > A (p.D487N). Our data indicate that T32KI mice have both a myopathic and a neurogenic phenotype, very similar to the one described in the Trim32-null mice that we created previously. Analysis of Trim32 gene expression in T32KI mice revealed normal mRNA levels, but a severe reduction in mutant TRIM32 (D489N) at the protein level. Our results suggest that the D489N pathogenic mutation destabilizes the protein, leading to its degradation, and results in the same mild myopathic and neurogenic phenotype as that found in Trim32-null mice. Thus, one potential mechanism of LGMD2H might be destabilization of mutated TRIM32 protein leading to a null phenotype. PMID:21775502

  5. Decreased TNF Levels and Improved Retinal Ganglion Cell Survival in MMP-2 Null Mice Suggest a Role for MMP-2 as TNF Sheddase

    PubMed Central

    De Groef, Lies; Salinas-Navarro, Manuel; Van Imschoot, Griet; Libert, Claude; Vandenbroucke, Roosmarijn E.; Moons, Lieve

    2015-01-01

    Matrix metalloproteinases (MMPs) have been designated as both friend and foe in the central nervous system (CNS): while being involved in many neurodegenerative and neuroinflammatory diseases, their actions appear to be indispensable to a healthy CNS. Pathological conditions in the CNS are therefore often related to imbalanced MMP activities and disturbances of the complex MMP-dependent protease network. Likewise, in the retina, various studies in animal models and human patients suggested MMPs to be involved in glaucoma. In this study, we sought to determine the spatiotemporal expression profile of MMP-2 in the excitotoxic retina and to unravel its role during glaucoma pathogenesis. We reveal that intravitreal NMDA injection induces MMP-2 expression to be upregulated in the Müller glia. Moreover, MMP-2 null mice display attenuated retinal ganglion cell death upon excitotoxic insult to the retina, which is accompanied by normal glial reactivity, yet reduced TNF levels. Hence, we propose a novel in vivo function for MMP-2, as an activating sheddase of tumor necrosis factor (TNF). Given the pivotal role of TNF as a proinflammatory cytokine and neurodegeneration-exacerbating mediator, these findings generate important novel insights into the pathological processes contributing to glaucomatous neurodegeneration and into the interplay of neuroinflammation and neurodegeneration in the CNS. PMID:26451076

  6. Null and hypomorph Prickle1 alleles in mice phenocopy human Robinow syndrome and disrupt signaling downstream of Wnt5a

    PubMed Central

    Liu, Chunqiao; Lin, Chen; Gao, Chun; May-Simera, Helen; Swaroop, Anand; Li, Tiansen

    2014-01-01

    ABSTRACT Planar cell polarity (PCP) signaling plays a critical role in tissue morphogenesis. In mammals, disruption of three of the six “core PCP” components results in polarity-dependent defects with rotated cochlear hair cell stereocilia and open neural tube. We recently demonstrated a role of Prickle1, a core PCP molecule in Drosophila, in mammalian neuronal development. To examine Prickle1 function along a broader developmental window, we generated three mutant alleles in mice. We show that the complete loss of Prickle1 leads to systemic tissue outgrowth defects, aberrant cell organization and disruption of polarity machinery. Curiously, Prickle1 mutants recapitulate the characteristic features of human Robinow syndrome and phenocopy mouse mutants with Wnt5a or Ror2 gene defects, prompting us to explore an association of Prickle1 with the Wnt pathway. We show that Prickle1 is a proteasomal target of Wnt5a signaling and that Dvl2, a target of Wnt5a signaling, is misregulated in Prickle1 mutants. Our studies implicate Prickle1 as a key component of the Wnt-signaling pathway and suggest that Prickle1 mediates some of the WNT5A-associated genetic defects in Robinow syndrome. PMID:25190059

  7. Differences in activation of ERK1/2 and p38 kinase in Jnk3 null mice following KA treatment.

    PubMed

    de Lemos, Luisa; Junyent, Fèlix; Verdaguer, Ester; Folch, Jaume; Romero, Rafael; Pallàs, Mercè; Ferrer, Isisdre; Auladell, Carme; Camins, Antoni

    2010-09-01

    The MAPK family is formed by extracellular signal-regulated kinases p38 kinase and stress-activated protein kinases (SAPK/JNK). There are three genes that encode for three JNK proteins. JNK3 is mainly expressed in the central nervous system and has been related to various processes in that tissue. Specifically, JNK3 plays a crucial role in neuronal death in several neurodegenerative diseases. The activation of this kinase has been described in epilepsy, Alzheimer's disease, Parkinson's disease and Huntington's disease. Different studies have shown that the lack of the Jnk3 gene confers neuroprotection. However, the specific mechanism involved in such neuroprotection has not yet been elucidated. Therefore, in the present study, we analyzed the neuroprotection in mice lacking Jnk3 against neuronal death induced by kainic acid. Moreover, we analyzed the activation of different MAPKs. The results revealed that neuronal death was attenuated and different activation/inactivation of p38 and extracellular signal-regulated kinases 1/2 was reported with respect to control. Therefore, the data indicate that the lack of the JNK3 protein modulates other MAPKs and these changes could also have a pivotal role in neuroprotection. PMID:20534003

  8. Altered gene expression patterns in muscle ring finger 1 null mice during denervation- and dexamethasone-induced muscle atrophy

    PubMed Central

    Watson, Monica L.; Waddell, David S.; Neff, Eric S.; Baehr, Leslie M.; Ross, Adam P.; Bodine, Sue C.

    2013-01-01

    Muscle atrophy can result from inactivity or unloading on one hand or the induction of a catabolic state on the other. Muscle-specific ring finger 1 (MuRF1), a member of the tripartite motif family of E3 ubiquitin ligases, is an essential mediator of multiple conditions inducing muscle atrophy. While most studies have focused on the role of MuRF1 in protein degradation, the protein may have other roles in regulating skeletal muscle mass and metabolism. We therefore systematically evaluated the effect of MuRF1 on gene expression during denervation and dexamethasone-induced atrophy. We find that the lack of MuRF1 leads to few differences in control animals, but there were several significant differences in specific sets of genes upon denervation- and dexamethasone-induced atrophy. For example, during denervation, MuRF1 knockout mice showed delayed repression of metabolic and structural genes and blunted induction of genes associated with the neuromuscular junction. In the latter case, this pattern correlates with blunted HDAC4 and myogenin upregulation. Lack of MuRF1 caused fewer changes in the dexamethasone-induced atrophy program, but certain genes involved in fat metabolism and intracellular signaling were affected. Our results demonstrate a new role for MuRF1 in influencing gene expression in two important models of muscle atrophy. PMID:24130153

  9. Nanoceria inhibit expression of genes associated with inflammation and angiogenesis in the retina of Vldlr null mice

    PubMed Central

    Kyosseva, Svetlana V.; Chen, Lijuan; Seal, Sudipta; McGinnis, James J.

    2013-01-01

    Oxidative stress and inflammation are important pathological mechanisms in many neurodegenerative diseases, including age-related macular degeneration (AMD). The Very Low-Density Lipoprotein Receptor knockout mouse (Vldlr−/−) has been identified as a model for AMD and in particular for Retinal Angiomatous Proliferation (RAP). In this study we examined the effect of cerium oxide nanoparticles (nanoceria) that have been shown to have catalytic antioxidant activity, on expression of 88 major cytokines in the retinas of Vldlr−/− mice using a PCR array. A single intravitrial injection of nanoceria at P28 caused inhibition of pro-inflammatory cytokines and pro-angiogenic growth factors including Tslp, Lif, Il-3, Il-7, Vegfa, Fgf1, Fgf2, Fgf7, Egf, Efna 3, Lep, and up-regulation of several cytokines and anti-angiogenic genes in the Vldlr−/−retina within one week. We used the Ingenuity Pathway Analysis software to search for biological functions, pathways, and interrelationships between gene networks. Many of the genes whose activities were affected are involved in cell signaling, cellular development, growth and proliferation, and tissue development. Western blot analysis revealed that nanoceria inhibit the activation of ERK 1/2, JNK, p38 MAP kinase, and Akt. These data suggest that nanoceria may represent a novel therapeutic strategy to treat AMD, RAP, and other neurodegenerative diseases. PMID:23978600

  10. Differential roles of endothelin-1 in angiotensin II-induced atherosclerosis and aortic aneurysms in apolipoprotein E-null mice.

    PubMed

    Suen, Renée S; Rampersad, Sarah N; Stewart, Duncan J; Courtman, David W

    2011-09-01

    Because both endothelin-1 (ET-1) and angiotensin II (AngII) are independent mediators of arterial remodeling, we sought to determine the role of ET receptor inhibition in AngII-accelerated atherosclerosis and aortic aneurysm formation. We administered saline or AngII and/or bosentan, an endothelin receptor antagonist (ERA) for 7, 14, or 28 days to 6-week- and 6-month-old apolipoprotein E-knockout mice. AngII treatment increased aortic atherosclerosis, which was reduced by ERA. ET-1 immunostaining was localized to macrophage-rich regions in aneurysmal vessels. ERA did not prevent AngII-induced aneurysm formation but instead may have increased aneurysm incidence. In AngII-treated animals with aneurysms, ERA had a profound effect on the non-aneurysmal thoracic aorta via increasing wall thickness, collagen/elastin ratio, wall stiffness, and viscous responses. These observations were confirmed in acute in vitro collagen sheet production models in which ERA inhibited AngII's dose-dependent effect on collagen type 1 α 1 (COL1A1) gene transcription. However, chronic treatment reduced matrix metalloproteinase 2 mRNA expression but enhanced COL3A1, tissue inhibitor of metalloproteinase 1 (TIMP-1), and TIMP-2 mRNA expressions. These data confirm a role for the ET system in AngII-accelerated atherosclerosis but suggest that ERA therapy is not protective against the formation of AngII-induced aneurysms and can paradoxically stimulate a chronic arterial matrix remodeling response. PMID:21718678

  11. Hyper-Variability in Circulating Insulin, High Fat Feeding Outcomes, and Effects of Reducing Ins2 Dosage in Male Ins1-Null Mice in a Specific Pathogen-Free Facility

    PubMed Central

    Templeman, Nicole M.; Mehran, Arya E.; Johnson, James D.

    2016-01-01

    Insulin is an essential hormone with key roles in energy homeostasis and body composition. Mice and rats, unlike other mammals, have two insulin genes: the rodent-specific Ins1 gene and the ancestral Ins2 gene. The relationships between insulin gene dosage and obesity has previously been explored in male and female Ins2-/- mice with full or reduced Ins1 dosage, as well as in female Ins1-/- mice with full or partial Ins2 dosage. We report herein unexpected hyper-variability in Ins1-null male mice, with respect to their circulating insulin levels and to the physiological effects of modulating Ins2 gene dosage. Two large cohorts of Ins1-/-:Ins2+/- mice and their Ins1-/-:Ins2+/+ littermates were fed chow diet or high fat diet (HFD) from weaning, and housed in specific pathogen-free conditions. Cohort A and cohort B were studied one year apart. Contrary to female mice from the same litters, inactivating one Ins2 allele on the complete Ins1-null background did not consistently cause a reduction of circulating insulin in male mice, on either diet. In cohort A, all HFD-fed males showed an equivalent degree of insulin hypersecretion and weight gain, regardless of Ins2 dosage. In cohort B the effects of HFD appeared generally diminished, and cohort B Ins1-/-:Ins2+/- males showed decreased insulin levels and body mass compared to Ins1-/-:Ins2+/+ littermates, on both diets. Although experimental conditions were consistent between cohorts, we found that HFD-fed Ins1-/-:Ins2+/- mice with lower insulin levels had increased corticosterone. Collectively, these observations highlight the phenotypic characteristics that change in association with differences in circulating insulin and Ins2 gene dosage, particularly in male mice. PMID:27055260

  12. Tbx22null mice have a submucous cleft palate due to reduced palatal bone formation and also display ankyloglossia and choanal atresia phenotypes.

    PubMed

    Pauws, Erwin; Hoshino, Aya; Bentley, Lucy; Prajapati, Suresh; Keller, Charles; Hammond, Peter; Martinez-Barbera, Juan-Pedro; Moore, Gudrun E; Stanier, Philip

    2009-11-01

    Craniofacial defects involving the lip and/or palate are among the most common human birth defects. X-linked cleft palate and ankyloglossia results from loss-of-function mutations in the gene encoding the T-box transcription factor TBX22. Further studies show that TBX22 mutations are also found in around 5% of non-syndromic cleft palate patients. Although palate defects are obvious at birth, the underlying developmental pathogenesis remains unclear. Here, we report a Tbx22(null) mouse, which has a submucous cleft palate (SMCP) and ankyloglossia, similar to the human phenotype, with a small minority showing overt clefts. We also find persistent oro-nasal membranes or, in some mice a partial rupture, resulting in choanal atresia. Each of these defects can cause severe breathing and/or feeding difficulties in the newborn pups, which results in approximately 50% post-natal lethality. Analysis of the craniofacial skeleton demonstrates a marked reduction in bone formation in the posterior hard palate, resulting in the classic notch associated with SMCP. Our results suggest that Tbx22 plays an important role in the osteogenic patterning of the posterior hard palate. Ossification is severely reduced after condensation of the palatal mesenchyme, resulting from a delay in the maturation of osteoblasts. Rather than having a major role in palatal shelf closure, we show that Tbx22 is an important determinant for intramembranous bone formation in the posterior hard palate, which underpins normal palate development and function. These findings could have important implications for the molecular diagnosis in patients with isolated SMCP and/or unexplained choanal atresia. PMID:19648291

  13. ILDR1 null mice, a model of human deafness DFNB42, show structural aberrations of tricellular tight junctions and degeneration of auditory hair cells

    PubMed Central

    Morozko, Eva L.; Nishio, Ayako; Ingham, Neil J.; Chandra, Rashmi; Fitzgerald, Tracy; Martelletti, Elisa; Borck, Guntram; Wilson, Elizabeth; Riordan, Gavin P.; Wangemann, Philine; Forge, Andrew; Steel, Karen P.; Liddle, Rodger A.; Friedman, Thomas B.; Belyantseva, Inna A.

    2015-01-01

    In the mammalian inner ear, bicellular and tricellular tight junctions (tTJs) seal the paracellular space between epithelial cells. Tricellulin and immunoglobulin-like (Ig-like) domain containing receptor 1 (ILDR1, also referred to as angulin-2) localize to tTJs of the sensory and non-sensory epithelia in the organ of Corti and vestibular end organs. Recessive mutations of TRIC (DFNB49) encoding tricellulin and ILDR1 (DFNB42) cause human nonsyndromic deafness. However, the pathophysiology of DFNB42 deafness remains unknown. ILDR1 was recently reported to be a lipoprotein receptor mediating the secretion of the fat-stimulated cholecystokinin (CCK) hormone in the small intestine, while ILDR1 in EpH4 mouse mammary epithelial cells in vitro was shown to recruit tricellulin to tTJs. Here we show that two different mouse Ildr1 mutant alleles have early-onset severe deafness associated with a rapid degeneration of cochlear hair cells (HCs) but have a normal endocochlear potential. ILDR1 is not required for recruitment of tricellulin to tTJs in the cochlea in vivo; however, tricellulin becomes mislocalized in the inner ear sensory epithelia of ILDR1 null mice after the first postnatal week. As revealed by freeze-fracture electron microscopy, ILDR1 contributes to the ultrastructure of inner ear tTJs. Taken together, our data provide insight into the pathophysiology of human DFNB42 deafness and demonstrate that ILDR1 is crucial for normal hearing by maintaining the structural and functional integrity of tTJs, which are critical for the survival of auditory neurosensory HCs. PMID:25217574

  14. ILDR1 null mice, a model of human deafness DFNB42, show structural aberrations of tricellular tight junctions and degeneration of auditory hair cells.

    PubMed

    Morozko, Eva L; Nishio, Ayako; Ingham, Neil J; Chandra, Rashmi; Fitzgerald, Tracy; Martelletti, Elisa; Borck, Guntram; Wilson, Elizabeth; Riordan, Gavin P; Wangemann, Philine; Forge, Andrew; Steel, Karen P; Liddle, Rodger A; Friedman, Thomas B; Belyantseva, Inna A

    2015-02-01

    In the mammalian inner ear, bicellular and tricellular tight junctions (tTJs) seal the paracellular space between epithelial cells. Tricellulin and immunoglobulin-like (Ig-like) domain containing receptor 1 (ILDR1, also referred to as angulin-2) localize to tTJs of the sensory and non-sensory epithelia in the organ of Corti and vestibular end organs. Recessive mutations of TRIC (DFNB49) encoding tricellulin and ILDR1 (DFNB42) cause human nonsyndromic deafness. However, the pathophysiology of DFNB42 deafness remains unknown. ILDR1 was recently reported to be a lipoprotein receptor mediating the secretion of the fat-stimulated cholecystokinin (CCK) hormone in the small intestine, while ILDR1 in EpH4 mouse mammary epithelial cells in vitro was shown to recruit tricellulin to tTJs. Here we show that two different mouse Ildr1 mutant alleles have early-onset severe deafness associated with a rapid degeneration of cochlear hair cells (HCs) but have a normal endocochlear potential. ILDR1 is not required for recruitment of tricellulin to tTJs in the cochlea in vivo; however, tricellulin becomes mislocalized in the inner ear sensory epithelia of ILDR1 null mice after the first postnatal week. As revealed by freeze-fracture electron microscopy, ILDR1 contributes to the ultrastructure of inner ear tTJs. Taken together, our data provide insight into the pathophysiology of human DFNB42 deafness and demonstrate that ILDR1 is crucial for normal hearing by maintaining the structural and functional integrity of tTJs, which are critical for the survival of auditory neurosensory HCs. PMID:25217574

  15. Peptide Mimetic of the S100A4 Protein Modulates Peripheral Nerve Regeneration and Attenuates the Progression of Neuropathy in Myelin Protein P0 Null Mice

    PubMed Central

    Moldovan, Mihai; Pinchenko, Volodymyr; Dmytriyeva, Oksana; Pankratova, Stanislava; Fugleholm, Kåre; Klingelhofer, Jorg; Bock, Elisabeth; Berezin, Vladimir; Krarup, Christian; Kiryushko, Darya

    2013-01-01

    We recently found that S100A4, a member of the multifunctional S100 protein family, protects neurons in the injured brain and identified two sequence motifs in S100A4 mediating its neurotrophic effect. Synthetic peptides encompassing these motifs stimulated neuritogenesis and survival in vitro and mimicked the S100A4-induced neuroprotection in brain trauma. Here, we investigated a possible function of S100A4 and its mimetics in the pathologies of the peripheral nervous system (PNS). We found that S100A4 was expressed in the injured PNS and that its peptide mimetic (H3) affected the regeneration and survival of myelinated axons. H3 accelerated electrophysiological, behavioral and morphological recovery after sciatic nerve crush while transiently delaying regeneration after sciatic nerve transection and repair. On the basis of the finding that both S100A4 and H3 increased neurite branching in vitro, these effects were attributed to the modulatory effect of H3 on initial axonal sprouting. In contrast to the modest effect of H3 on the time course of regeneration, H3 had a long-term neuroprotective effect in the myelin protein P0 null mice, a model of dysmyelinating neuropathy (Charcot-Marie-Tooth type 1 disease), where the peptide attenuated the deterioration of nerve conduction, demyelination and axonal loss. From these results, S100A4 mimetics emerge as a possible means to enhance axonal sprouting and survival, especially in the context of demyelinating neuropathies with secondary axonal loss, such as Charcot-Marie-Tooth type 1 disease. Moreover, our data suggest that S100A4 is a neuroprotectant in PNS and that other S100 proteins, sharing high homology in the H3 motif, may have important functions in PNS pathologies. PMID:23508572

  16. The heparan sulphate deficient Hspg2 exon 3 null mouse displays reduced deposition of TGF-β1 in skin compared to C57BL/6 wild type mice.

    PubMed

    Shu, Cindy; Smith, Susan M; Melrose, James

    2016-06-01

    This was an observational study where we examined the role of perlecan HS on the deposition of TGF-β1 in C57BL/6 and Hspg2(∆3-/∆3-) perlecan exon 3 null mouse skin. Despite its obvious importance in skin repair and tissue homeostasis no definitive studies have immunolocalised TGF-β1 in skin in WT or Hspg2(∆3-/∆3-) perlecan exon 3 null mice. Vertical parasagittal murine dorsal skin from 3, 6 and 12 week old C57BL/6 and Hspg2(∆3-/∆3-) mice were fixed in neutral buffered formalin, paraffin embedded and 4 μm sections stained with Mayers haematoxylin and eosin (H & E). TGF-β1 was immunolocalised using a rabbit polyclonal antibody, heat retrieval and the Envision NovaRED detection system. Immunolocalisation of TGF-β1 differed markedly in C57BL/6 and Hspg2(∆3-/∆3-) mouse skin, ablation of exon 3 of Hspg2 resulted in a very severe reduction in the deposition of TGF-β1 in skin 3-12 weeks postnatally. The reduced deposition of TGF-β1 observed in the present study would be expected to impact detrimentally on the remodelling and healing capacity of skin in mutant mice compounding on the poor wound-healing properties already reported for perlecan exon 3 null mice due to an inability to signal with FGF-2 and promote angiogenic repair processes. TGF-β1 also has cell mediated effects in tissue homeostasis and matrix stabilisation a reduction in TGF-β1 deposition would therefore be expected to detrimentally impact on skin homeostasis in the perlecan mutant mice. PMID:27098652

  17. Sensitization to autoimmune hepatitis in group VIA calcium-independent phospholipase A2-null mice led to duodenal villous atrophy with apoptosis, goblet cell hyperplasia and leaked bile acids.

    PubMed

    Jiao, Li; Gan-Schreier, Hongying; Tuma-Kellner, Sabine; Stremmel, Wolfgang; Chamulitrat, Walee

    2015-08-01

    Chronic bowel disease can co-exist with severe autoimmune hepatitis (AIH) in an absence of primary sclerosing cholangitis. Genetic background may contribute to this overlap syndrome. We previously have shown that the deficiency of iPLA2β causes an accumulation of hepatocyte apoptosis, and renders susceptibility for acute liver injury. We here tested whether AIH induction in iPLA2β-null mice could result in intestinal injury, and whether bile acid metabolism was altered. Control wild-type (WT) and female iPLA2β-null (iPLA2β(-/-)) mice were intravenously injected with 10mg/kg concanavalinA (ConA) or saline for 24h. ConA treatment of iPLA2β(-/-) mice caused massive liver injury with increased liver enzymes, fibrosis, and necrosis. While not affecting WT mice, ConA treatment of iPLA2β(-/-) mice caused severe duodenal villous atrophy concomitant with increased apoptosis, cell proliferation, globlet cell hyperplasia, and endotoxin leakage into portal vein indicating a disruption of intestinal barrier. With the greater extent than in WT mice, ConA treatment of iPLA2β(-/-) mice increased jejunal expression of innate response cytokines CD14, TNF-α, IL-6, and SOCS3 as well as chemokines CCL2 and the CCL3 receptor CCR5. iPLA2β deficiency in response to ConA-induced AIH caused a significant decrease in hepatic and biliary bile acids, and this was associated with suppression of hepatic Cyp7A1, Ntcp and ABCB11/Bsep and upregulation of intestinal FXR/FGF15 mRNA expression. The suppression of hepatic Ntcp expression together with the loss of intestinal barrier could account for the observed bile acid leakage into peripheral blood. Thus, enteropathy may result from acute AIH in a susceptible host such as iPLA2β deficiency. PMID:25957555

  18. Human immune system development and survival of non-obese diabetic (NOD)-scid IL2rγnull (NSG) mice engrafted with human thymus and autologous haematopoietic stem cells

    PubMed Central

    Covassin, L; Jangalwe, S; Jouvet, N; Laning, J; Burzenski, L; Shultz, L D; Brehm, M A

    2013-01-01

    Immunodeficient mice bearing targeted mutations in the IL2rg gene and engrafted with human immune systems are effective tools for the study of human haematopoiesis, immunity, infectious disease and transplantation biology. The most robust human immune model is generated by implantation of human fetal thymic and liver tissues in irradiated recipients followed by intravenous injection of autologous fetal liver haematopoietic stem cells [often referred to as the BLT (bone marrow, liver, thymus) model]. To evaluate the non-obese diabetic (NOD)-scid IL2rγnull (NSG)–BLT model, we have assessed various engraftment parameters and how these parameters influence the longevity of NSG–BLT mice. We observed that irradiation and subrenal capsule implantation of thymus/liver fragments was optimal for generating human immune systems. However, after 4 months, a high number of NSG–BLT mice develop a fatal graft-versus-host disease (GVHD)-like syndrome, which correlates with the activation of human T cells and increased levels of human immunoglobulin (Ig). Onset of GVHD was not delayed in NSG mice lacking murine major histocompatibility complex (MHC) classes I or II and was not associated with a loss of human regulatory T cells or absence of intrathymic cells of mouse origin (mouse CD45+). Our findings demonstrate that NSG–BLT mice develop robust human immune systems, but that the experimental window for these mice may be limited by the development of GVHD-like pathological changes. PMID:23869841

  19. Effects of D-4F on Vasodilation and Vessel Wall Thickness in Hypercholesterolemic LDL Receptor Null and LDL receptor/ApoA-I Double Knockout Mice on Western Diet

    PubMed Central

    Ou, Jingsong; Wang, Jingli; Xu, Hao; Ou, Zhijun; Sorci-Thomas, Mary G.; Jones, Deron W.; Signorino, Paul; Densmore, John C.; Kaul, Sushma; Oldham, Keith T.; Pritchard, Kirkwood A.

    2005-01-01

    Previously we showed L-4F, a novel apolipoprotein A-I (apoA-I) mimetic, improved vasodilation in two dissimilar models of vascular disease; hypercholesterolemic low-density lipoprotein (LDL) receptor null (Ldlr −/−) mice and transgenic sickle cell disease mice. Here we determine the mechanisms by which D-4F improves vasodilation and arterial wall thickness in hypercholesterolemic Ldlr −/− mice and Ldlr −/−/apoA-I null (apoA-I −/−), double knockout mice. Ldlr −/− and Ldlr −/−/apoA-I −/− mice were fed western diet (WD) ± D-4F. Oral D-4F restored endothelium- and eNOS-dependent vasodilation in direct relationship to duration of treatments and reduced wall thickness in as little as 2 weeks in vessels with pre-existing disease in Ldlr −/− mice. D-4F had no effect on total or HDL cholesterol concentrations but reduced proinflammatory HDL levels. D-4F had no effect on plasma myeloperoxidase (MPO) concentrations but reduced MPO association with apoA-I as well as 3-nitrotyrosine in apoA-I. D-4F increased endothelium- and eNOS-dependent vasodilation in Ldlr −/−/apoA-I −/− mice but did not reduce wall thickness as it had in Ldlr −/− mice. Vascular endothelial cells were treated with 22-hydroxycholesterol (22-OHC) ± L-4F. 22-OHC decreased nitric oxide (•NO) and increased superoxide anion (O2 •−) production and increased ABCA-1 and collagen expression. L-4F restored •NO and O2 •− balance, had little effect on ABCA-1 expression but reduced collagen expression. These data demonstrate that although D-4F restores vascular endothelial cell and eNOS function to increase vasodilation, HDL containing apoA-I, or at least some critical concentration of the anti-atherogenic lipoprotein, is required for D-4F to decrease vessel wall thickness. PMID:16224061

  20. Application of Osmotic Pumps for Sustained Release of 1-Aminobenzotriazole and Inhibition of Cytochrome P450 Enzymes in Mice: Model Comparison with the Hepatic P450 Reductase Null Mouse.

    PubMed

    Stringer, Rowan A; Ferreira, Suzie; Rose, Jonathan; Ronseaux, Sebastien

    2016-08-01

    The effectiveness of controlled release 1-aminobenzotriazole (ABT) administration to inhibit cytochrome P450 (P450) enzymes has been evaluated in mice. To maximize the duration of P450 inhibition in vivo, ABT was administered via an osmotic pump. The degree of P450 inhibition was compared with that achieved with a single bolus dose of ABT. Two-hour prior subcutaneous treatment of mice with ABT (50 mg/kg) inhibited antipyrine clearance by 88%. A less pronounced inhibitory effect (29% reduction in clearance) was observed when ABT was administered 24-hours before antipyrine administration, indicating partial restoration of P450 activity during this longer pretreatment time. The duration of ABT in mice was very short (mean residence time = 1.7 hours) after subcutaneous bolus administration. When the inhibitor was delivered by an osmotic pump, maximum blood concentrations of the inhibitor were observed 24 hours after device implantation and were maintained at steady state for 6 days. Inhibition of P450 activity, as measured by antipyrine clearance, was confirmed at 24 hours and 120 hours after pump implantation, highlighting the utility of this method as a longer-term model for P450 inhibition in mice. The magnitude of P450 inhibition in ABT-treated mice was compared with that in hepatic P450 reductase null mice and both models were comparable. In vivo ABT administration by an osmotic pump offers an effective approach for longer-term P450 inhibition in mice and avoids the necessity for multiple dosing of the inhibitor. PMID:27271368

  1. Apolipoprotein A-I Mimetic Peptide D-4F Reduces Cardiac Hypertrophy and Improves Apolipoprotein A-I-Mediated Reverse Cholesterol Transport From Cardiac Tissue in LDL Receptor-null Mice Fed a Western Diet.

    PubMed

    Han, Jie; Zhang, Song; Ye, Ping; Liu, Yong-Xue; Qin, Yan-Wen; Miao, Dong-Mei

    2016-05-01

    Epidemiological studies have suggested that hypercholesterolemia is an independent determinant of increased left ventricular (LV) mass. Because high-density lipoprotein and its major protein apolipoprotein A-I (apoA-I) mediate reverse cholesterol transport (RCT) and have cardiac protective effects, we hypothesized that the apoA-I mimetic peptide D-4F could promote RCT in cardiac tissue and decrease cardiac hypertrophy induced by hypercholesterolemia. Low-density lipoprotein receptor-null mice were fed by a Western diet for 18 weeks and then randomized to receive water, or D-4F 0.3 mg/mL, or D-4F 0.5 mg/mL added to drinking water for 6 weeks. After D-4F administration, an increase in high-density lipoprotein cholesterol and a decrease in low-density lipoprotein cholesterol, total cholesterol, and triglyceride in a trend toward dose-responsivity were found in cardiac tissue. Ultrasound biomicroscopy revealed a reduction in LV posterior wall end-diastolic dimension, and an increase in mitral valve E/A ratio and LV ejection fraction. Hematoxylin-eosin staining showed reduced LV wall thickness and myocardial cell diameter. The protein levels of ABCA1 and LXRα were elevated in cardiac tissue of D-4F treated mice compared with the controls (P < 0.05). These results demonstrated that D-4F treatment reduced cardiac hypertrophy, and improved cardiac performance in low-density lipoprotein receptor-null mice fed a Western diet, presumably through the LXRα-ABCA1 pathway associated with enhanced myocardial RCT. PMID:26828321

  2. Direct comparison of mice null for liver or intestinal fatty acid-binding proteins reveals highly divergent phenotypic responses to high fat feeding.

    PubMed

    Gajda, Angela M; Zhou, Yin Xiu; Agellon, Luis B; Fried, Susan K; Kodukula, Sarala; Fortson, Walter; Patel, Khamoshi; Storch, Judith

    2013-10-18

    The enterocyte expresses two fatty acid-binding proteins (FABP), intestinal FABP (IFABP; FABP2) and liver FABP (LFABP; FABP1). LFABP is also expressed in liver. Despite ligand transport and binding differences, it has remained uncertain whether these intestinally coexpressed proteins, which both bind long chain fatty acids (FA), are functionally distinct. Here, we directly compared IFABP(-/-) and LFABP(-/-) mice fed high fat diets containing long chain saturated or unsaturated fatty acids, reasoning that providing an abundance of dietary lipid would reveal unique functional properties. The results showed that mucosal lipid metabolism was indeed differentially modified, with significant decreases in FA incorporation into triacylglycerol (TG) relative to phospholipid (PL) in IFABP(-/-) mice, whereas LFABP(-/-) mice had reduced monoacylglycerol incorporation in TG relative to PL, as well as reduced FA oxidation. Interestingly, striking differences were found in whole body energy homeostasis; LFABP(-/-) mice fed high fat diets became obese relative to WT, whereas IFABP(-/-) mice displayed an opposite, lean phenotype. Fuel utilization followed adiposity, with LFABP(-/-) mice preferentially utilizing lipids, and IFABP(-/-) mice preferentially metabolizing carbohydrate for energy production. Changes in body weight and fat may arise, in part, from altered food intake; mucosal levels of the endocannabinoids 2-arachidonoylglycerol and arachidonoylethanolamine were elevated in LFABP(-/-), perhaps contributing to increased energy intake. This direct comparison provides evidence that LFABP and IFABP have distinct roles in intestinal lipid metabolism; differential intracellular functions in intestine and in liver, for LFABP(-/-) mice, result in divergent downstream effects at the systemic level. PMID:23990461

  3. Direct Comparison of Mice Null for Liver or Intestinal Fatty Acid-binding Proteins Reveals Highly Divergent Phenotypic Responses to High Fat Feeding*

    PubMed Central

    Gajda, Angela M.; Zhou, Yin Xiu; Agellon, Luis B.; Fried, Susan K.; Kodukula, Sarala; Fortson, Walter; Patel, Khamoshi; Storch, Judith

    2013-01-01

    The enterocyte expresses two fatty acid-binding proteins (FABP), intestinal FABP (IFABP; FABP2) and liver FABP (LFABP; FABP1). LFABP is also expressed in liver. Despite ligand transport and binding differences, it has remained uncertain whether these intestinally coexpressed proteins, which both bind long chain fatty acids (FA), are functionally distinct. Here, we directly compared IFABP−/− and LFABP−/− mice fed high fat diets containing long chain saturated or unsaturated fatty acids, reasoning that providing an abundance of dietary lipid would reveal unique functional properties. The results showed that mucosal lipid metabolism was indeed differentially modified, with significant decreases in FA incorporation into triacylglycerol (TG) relative to phospholipid (PL) in IFABP−/− mice, whereas LFABP−/− mice had reduced monoacylglycerol incorporation in TG relative to PL, as well as reduced FA oxidation. Interestingly, striking differences were found in whole body energy homeostasis; LFABP−/− mice fed high fat diets became obese relative to WT, whereas IFABP−/− mice displayed an opposite, lean phenotype. Fuel utilization followed adiposity, with LFABP−/− mice preferentially utilizing lipids, and IFABP−/− mice preferentially metabolizing carbohydrate for energy production. Changes in body weight and fat may arise, in part, from altered food intake; mucosal levels of the endocannabinoids 2-arachidonoylglycerol and arachidonoylethanolamine were elevated in LFABP−/−, perhaps contributing to increased energy intake. This direct comparison provides evidence that LFABP and IFABP have distinct roles in intestinal lipid metabolism; differential intracellular functions in intestine and in liver, for LFABP−/− mice, result in divergent downstream effects at the systemic level. PMID:23990461

  4. Up-regulation of Thrombospondin-2 in Akt1-null Mice Contributes to Compromised Tissue Repair Due to Abnormalities in Fibroblast Function*

    PubMed Central

    Bancroft, Tara; Bouaouina, Mohamed; Roberts, Sophia; Lee, Monica; Calderwood, David A.; Schwartz, Martin; Simons, Michael; Sessa, William C.; Kyriakides, Themis R.

    2015-01-01

    Vascular remodeling is essential for tissue repair and is regulated by multiple factors, including thrombospondin-2 (TSP2) and hypoxia/VEGF-induced activation of Akt. In contrast to TSP2 knock-out (KO) mice, Akt1 KO mice have elevated TSP2 expression and delayed tissue repair. To investigate the contribution of increased TSP2 to Akt1 KO mice phenotypes, we generated Akt1/TSP2 double KO (DKO) mice. Full-thickness excisional wounds in DKO mice healed at an accelerated rate when compared with Akt1 KO mice. Isolated dermal Akt1 KO fibroblasts expressed increased TSP2 and displayed altered morphology and defects in migration and adhesion. These defects were rescued in DKO fibroblasts or after TSP2 knockdown. Conversely, the addition of exogenous TSP2 to WT cells induced cell morphology and migration rates that were similar to those of Akt1 KO cells. Akt1 KO fibroblasts displayed reduced adhesion to fibronectin with manganese stimulation when compared with WT and DKO cells, revealing an Akt1-dependent role for TSP2 in regulating integrin-mediated adhesions; however, this effect was not due to changes in β1 integrin surface expression or activation. Consistent with these results, Akt1 KO fibroblasts displayed reduced Rac1 activation that was dependent upon expression of TSP2 and could be rescued by a constitutively active Rac mutant. Our observations show that repression of TSP2 expression is a critical aspect of Akt1 function in tissue repair. PMID:25389299

  5. FE65 and FE65L1 amyloid precursor protein-binding protein compound null mice display adult-onset cataract and muscle weakness.

    PubMed

    Suh, Jaehong; Moncaster, Juliet A; Wang, Lirong; Hafeez, Imran; Herz, Joachim; Tanzi, Rudolph E; Goldstein, Lee E; Guénette, Suzanne Y

    2015-06-01

    FE65 and FE65L1 are cytoplasmic adaptor proteins that bind a variety of proteins, including the amyloid precursor protein, and that mediate the assembly of multimolecular complexes. We previously reported that FE65/FE65L1 double knockout (DKO) mice display disorganized laminin in meningeal fibroblasts and a cobblestone lissencephaly-like phenotype in the developing cortex. Here, we examined whether loss of FE65 and FE65L1 causes ocular and muscular deficits, 2 phenotypes that frequently accompany cobblestone lissencephaly. Eyes of FE65/FE65L1 DKO mice develop normally, but lens degeneration becomes apparent in young adult mice. Abnormal lens epithelial cell migration, widespread small vacuole formation, and increased laminin expression underneath lens capsules suggest impaired interaction between epithelial cells and capsular extracellular matrix in DKO lenses. Cortical cataracts develop in FE65L1 knockout (KO) mice aged 16 months or more but are absent in wild-type or FE65 KO mice. FE65 family KO mice show attenuated grip strength, and the nuclei of DKO muscle cells frequently locate in the middle of muscle fibers. These findings reveal that FE65 and FE65L1 are essential for the maintenance of lens transparency, and their loss produce phenotypes in brain, eye, and muscle that are comparable to the clinical features of congenital muscular dystrophies in humans. PMID:25757569

  6. Sex Differences in Ethanol’s Anxiolytic Effect and Chronic Ethanol Withdrawal Severity in Mice With a Null Mutation of the 5α-Reductase Type 1 Gene

    PubMed Central

    Tanchuck-Nipper, Michelle A.; Ford, Matthew M.; Hertzberg, Anna; Beadles-Bohling, Amy; Cozzoli, Debra K.; Finn, Deborah A.

    2015-01-01

    Manipulation of endogenous levels of the GABAergic neurosteroid allopregnanolone alters sensitivity to some effects of ethanol. Chronic ethanol withdrawal decreases activity and expression of 5α-reductase-1, an important enzyme in allopregnanolone biosynthesis encoded by the 5α-reductase-1 gene (Srd5a1). The present studies examined the impact of Srd5a1 deletion in male and female mice on several acute effects of ethanol and on chronic ethanol withdrawal severity. Genotype and sex did not differentially alter ethanol-induced hypothermia, ataxia, hypnosis, or metabolism, but ethanol withdrawal was significantly lower in female versus male mice. On the elevated plus maze, deletion of the Srd5a1 gene significantly decreased ethanol’s effect on total entries versus wildtype (WT) mice and significantly decreased ethanol’s anxiolytic effect in female knockout (KO) versus WT mice. The limited sex differences in the ability of Srd5a1 genotype to modulate select ethanol effects may reflect an interaction between developmental compensations to deletion of the Srd5a1 gene with sex hormones and levels of endogenous neurosteroids. PMID:25355320

  7. Alteration of BACE1-dependent NRG1/ErbB4 signaling and schizophrenia-like phenotypes in BACE1-null mice.

    PubMed

    Savonenko, A V; Melnikova, T; Laird, F M; Stewart, K-A; Price, D L; Wong, P C

    2008-04-01

    beta-Site APP-cleaving enzyme 1 (BACE1) is required for the penultimate cleavage of the amyloid-beta precursor protein (APP) leading to the generation of amyloid-beta peptides that is central to the pathogenesis of Alzheimer's disease. In addition to its role in endoproteolysis of APP, BACE1 participates in the proteolytic processing of neuregulin 1 (NRG1) and influences the myelination of central and peripheral axons. Although NRG1 has been genetically linked to schizophrenia and NRG1(+/-) mice exhibit a number of schizophrenia-like behavioral traits, it is not known whether altered BACE1-dependent NRG1 signaling can cause similar behavioral abnormalities. To test this hypothesis, we analyze the behaviors considered to be rodent analogs of clinical features of schizophrenia in BACE1(-/-) mice with impaired processing of NRG1. We demonstrate that BACE1(-/-) mice exhibit deficits in prepulse inhibition, novelty-induced hyperactivity, hypersensitivity to a glutamatergic psychostimulant (MK-801), cognitive impairments, and deficits in social recognition. Importantly, some of these manifestations were responsive to treatment with clozapine, an atypical antipsychotic drug. Moreover, although the total amount of ErbB4, a receptor for NRG1 was not changed, binding of ErbB4 with postsynaptic density protein 95 (PSD95) was significantly reduced in the brains of BACE1(-/-) mice. Consistent with the role of ErbB4 in spine morphology and synaptic function, BACE1(-/-) mice displayed reduced spine density in hippocampal pyramidal neurons. Collectively, our findings suggest that alterations in BACE1-dependent NRG1/ErbB4 signaling may participate in the pathogenesis of schizophrenia and related psychiatric disorders. PMID:18385378

  8. The antidepressant-like effects of glutamatergic drugs ketamine and AMPA receptor potentiator LY 451646 are preserved in bdnf⁺/⁻ heterozygous null mice.

    PubMed

    Lindholm, Jesse S O; Autio, Henri; Vesa, Liisa; Antila, Hanna; Lindemann, Lothar; Hoener, Marius C; Skolnick, Phil; Rantamäki, Tomi; Castrén, Eero

    2012-01-01

    Accumulating evidence suggests that biogenic amine-based antidepressants act, at least in part, via regulation of brain-derived neurotrophic factor (BDNF) signaling. Biogenic amine-based antidepressants increase BDNF synthesis and activate its signaling pathway through TrkB receptors. Moreover, the antidepressant-like effects of these molecules are abolished in BDNF deficient mice. Glutamate-based drugs, including the NMDA antagonist ketamine, and the AMPA receptor potentiator LY 451646, mimic the effects of antidepressants in preclinical tests with high predictive validity. In humans, a single intravenous dose of ketamine produces an antidepressant effect that is rapid, robust and persistent. In this study, we examined the role of BDNF in expression of the antidepressant-like effects of ketamine and an AMPA receptor potentiator (LY 451646) in the forced swim test (FST). Ketamine and LY 451646 produced antidepressant-like effects in the FST in mice at 45 min after a single injection, but no effects were observed one week after a single ketamine injection. As previously reported, the effects of imipramine in the forced swim test were blunted in heterozygous BDNF knockout (bdnf(+/-)) mice. However ketamine and LY 451646 produced similar antidepressant-like responses in wildtype and bdnf(+/-) mice. Neither ketamine nor LY 451646 significantly influenced the levels BDNF or TrkB phosphorylation in the hippocampus when assessed at 45 min or 7 days after the drug administration. These data demonstrate that under the conditions tested, neither ketamine nor the AMPA-potentiator LY 451656 activate BDNF signaling, but produce a characteristic antidepressant-like response in heterozygous bdnf(+/-) mice. These data indicate that unlike biogenic amine-based agents, BDNF signaling does not play a pivotal role in the antidepressant effects of glutamate-based compounds. This article is part of a Special Issue entitled 'Anxiety and Depression'. PMID:21867718

  9. Fusobacterium nucleatum Alters Atherosclerosis Risk Factors and Enhances Inflammatory Markers with an Atheroprotective Immune Response in ApoE(null) Mice.

    PubMed

    Velsko, Irina M; Chukkapalli, Sasanka S; Rivera-Kweh, Mercedes F; Chen, Hao; Zheng, Donghang; Bhattacharyya, Indraneel; Gangula, Pandu R; Lucas, Alexandra R; Kesavalu, Lakshmyya

    2015-01-01

    The American Heart Association supports an association between periodontal disease (PD) and atherosclerotic vascular disease (ASVD) but does not as of yet support a causal relationship. Recently, we have shown that major periodontal pathogens Porphyromonas gingivalis and Treponema denticola are causally associated with acceleration of aortic atherosclerosis in ApoEnull hyperlipidemic mice. The aim of this study was to determine if oral infection with another significant periodontal pathogen Fusobacterium nucleatum can accelerate aortic inflammation and atherosclerosis in the aortic artery of ApoEnull mice. ApoEnull mice (n = 23) were orally infected with F. nucleatum ATCC 49256 and euthanized at 12 and 24 weeks. Periodontal disease assessments including F. nucleatum oral colonization, gingival inflammation, immune response, intrabony defects, and alveolar bone resorption were evaluated. Systemic organs were evaluated for infection, aortic sections were examined for atherosclerosis, and inflammatory markers were measured. Chronic oral infection established F. nucleatum colonization in the oral cavity, induced significant humoral IgG (P=0.0001) and IgM (P=0.001) antibody response (12 and 24 weeks), and resulted in significant (P=0.0001) alveolar bone resorption and intrabony defects. F. nucleatum genomic DNA was detected in systemic organs (heart, aorta, liver, kidney, lung) indicating bacteremia. Aortic atherosclerotic plaque area was measured and showed a local inflammatory infiltrate revealed the presence of F4/80+ macrophages and CD3+ T cells. Vascular inflammation was detected by enhanced systemic cytokines (CD30L, IL-4, IL-12), oxidized LDL and serum amyloid A, as well as altered serum lipid profile (cholesterol, triglycerides, chylomicrons, VLDL, LDL, HDL), in infected mice and altered aortic gene expression in infected mice. Despite evidence for systemic infection in several organs and modulation of known atherosclerosis risk factors, aortic atherosclerotic

  10. Augmented atherogenesis in ApoE-null mice co-exposed to polychlorinated biphenyls and 2,3,7,8-tetrachlorodibenzo-p-dioxin

    SciTech Connect

    Shan, Qiuli; Wang, Jing; Huang, Fengchen; Lv, Xiaowen; Ma, Min; Du, Yuguo

    2014-04-15

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and polychlorinated biphenyls (PCBs) are persistent organic pollutants found as complex mixtures in the environment throughout the world. Therefore, humans are ubiquitously and simultaneously exposed to TCDD and PCBs. TCDD and PCBs alone have been linked to atherosclerosis. However, the effects of interactions or synergism between TCDD and PCBs on atherogenesis are unknown. We investigated the possible enhanced atherogenesis by co-exposure to TCDD and PCBs and the potential mechanism(s) involved in this enhancement. Male ApoE{sup −/−} mice were exposed to TCDD (15 μg/kg) and Aroclor1254 (55 mg/kg, a representative mixture of PCBs) alone or in combination by intraperitoneal injection four times over six weeks of duration. Our results showed that mice exposed to TCDD alone, but not Aroclor1254 alone, developed atherosclerotic lesions. Moreover, we found that atherosclerotic disease was exacerbated to the greatest extent in mice co-exposed to TCDD and Aroclor1254. The enhanced lesions correlated with several pro-atherogenic changes, including a marked increase in the accumulation of the platelet-derived chemokine PF4, and the expression of the proinflammatory cytokine MCP-1 and the critical immunity gene-RIG-I. Our data demonstrated that co-exposure to TCDD and Aroclor1254 markedly enhanced atherogenesis in ApoE{sup −/−} mice. Significantly, our observations suggest that combined exposure to TCDD and PCBs may be a greater cardiovascular health risk than previously anticipated from individual studies. - Highlights: • Augmented atherogenesis was found in ApoE{sup −/−} mice co-exposed to Aroclor1254 and TCDD. • Enhanced expression of PF4, MCP-1 and RIG-I correlated with augmented lesions. • POPs combination may be a greater cardiovascular health risk than individual POPs.

  11. Reorganization of GABAergic circuits maintains GABAA receptor-mediated transmission onto CA1 interneurons in alpha1-subunit-null mice.

    PubMed

    Schneider Gasser, Edith M; Duveau, Venceslas; Prenosil, George A; Fritschy, Jean-Marc

    2007-06-01

    The majority of hippocampal interneurons strongly express GABA(A) receptors containing the alpha1 subunit, suggesting that inhibitory control of interneurons is important for proper function of hippocampal circuits. Here, we investigated with immunohistochemical and electrophysiological techniques how these GABA(A) receptors are replaced in mice carrying a targeted deletion of the alpha1-subunit gene (alpha1(0/0) mice). Using markers of five major populations of CA1 interneurons (parvalbumin, calretinin, calbindin, neuropeptide Y and somatostatin), we show that these interneurons remain unaffected in alpha1(0/0) mice. In triple immunofluorescence staining experiments combining these markers with the GABA(A) receptor alpha1, alpha2 or alpha3 subunit and gephyrin, we demonstrate a strong increase in alpha3- and alpha2-GABA(A) receptors clustered at postsynaptic sites along with gephyrin in most CA1 interneurons in alpha1(0/0) mice. The changes were cell type-specific and resulted in an increased number of GABAergic synapses on interneurons. These adjustments were mirrored functionally by retention of spontaneous IPSCs with prolonged decay kinetics, as shown by whole-cell patch-clamp recordings of CA1 interneurons. However, a significant decrease in frequency and amplitude of miniature IPSCs was evident, suggesting reduced affinity of postsynaptic receptors and/or impaired vesicular GABA release. Finally, to assess whether these compensatory changes are sufficient to protect against a pathological challenge, we tested the susceptibility of alpha1(0/0) mice against kainic acid-induced excitotoxicity. No genotype difference was observed in the effects of kainic acid, indicating that the absence of a major GABA(A) receptor subtype is functionally compensated for in hippocampal interneurons by a reorganization of inhibitory circuits. PMID:17552997

  12. Increased susceptibility of annexin-A1 null mice to nociceptive pain is indicative of a spinal antinociceptive action of annexin-A1

    PubMed Central

    Ayoub, S S; Yazid, S; Flower, R J

    2008-01-01

    Background and purpose: Annexin-A1 (ANXA1), a glucocorticoid-regulated protein, mediates several of the anti-inflammatory actions of the glucocorticoids. Previous studies demonstrated that ANXA1 is involved in pain modulation. The current study, using ANXA1 knockout mice (ANXA1−/−), is aimed at addressing the site and mechanism of the modulatory action of ANXA1 as well as possible involvement of ANXA1 in mediating the analgesic action of glucocorticoids. Experimental approach: The acetic acid-induced writhing response was performed in ANXA1−/− and wild-type (ANXA1+/+) mice with spinal and brain levels of prostaglandin E2 (PGE2) examined in both genotypes. The effect of the ANXA1 peptomimetic Ac2-26 as well as methylprednisolone on the writhing response and on spinal cord PGE2 of ANXA1+/+ and ANXA1−/− was compared. The expression of proteins involved in PGE2 synthesis, cytosolic phospholipase A2 (cPLA2) and cyclooxygenases (COXs), in the spinal cord of ANXA1+/+ and ANXA1−/− was also compared. Key results: ANXA1−/− mice exhibited a significantly greater writhing response and increased spinal cord levels of PGE2 compared with ANXA1+/+ mice. Ac2-26 produced analgesia and reduced spinal PGE2 levels in ANXA1+/+ and ANXA1−/− mice, whereas methylprednisolone reduced the writhing response and spinal PGE2 levels in ANXA1+/+, but not in ANXA1−/− mice. The expression of cPLA2, COX-1, COX-2 and COX-3 in spinal cord tissues was upregulated in ANXA1−/−compared with ANXA1+/+. Conclusions and implications: We conclude that ANXA1 protein modulates nociceptive processing at the spinal level, by reducing synthesis of PGE2 by modulating cPLA2 and/or COX activity. The analgesic activity of methylprednisolone is mediated by spinal ANXA1. PMID:18469846

  13. Comparison of Effects of p53 Null and Gain-of-Function Mutations on Salivary Tumors in MMTV-Hras Transgenic Mice

    PubMed Central

    Jiang, Dadi; Dumur, Catherine I.; Massey, H. Davis; Ramakrishnan, Viswanathan; Subler, Mark A.; Windle, Jolene J.

    2015-01-01

    p53 is an important tumor suppressor gene which is mutated in ~50% of all human cancers. Some of these mutants appear to have acquired novel functions beyond merely losing wild-type functions. To investigate these gain-of-function effects in vivo, we generated mice of three different genotypes: MMTV-Hras/p53+/+, MMTV-Hras/p53-/-, and MMTV-Hras/p53R172H/R172H. Salivary tumors from these mice were characterized with regard to age of tumor onset, tumor growth rates, cell cycle distribution, apoptotic levels, tumor histopathology, as well as response to doxorubicin treatment. Microarray analysis was also performed to profile gene expression. The MMTV-Hras/p53-/- and MMTV-Hras/p53R172H/R172H mice displayed similar properties with regard to age of tumor onset, tumor growth rates, tumor histopathology, and response to doxorubicin, while both groups were clearly distinct from the MMTV-Hras/p53+/+ mice by these measurements. In addition, the gene expression profiles of the MMTV-Hras/p53-/- and MMTV-Hras/p53R172H/R172H tumors were tightly clustered, and clearly distinct from the profiles of the MMTV-Hras/p53+/+ tumors. Only a small group of genes showing differential expression between the MMTV-Hras/p53-/- and MMTV-Hras/p53R172H/R172H tumors, that did not appear to be regulated by wild-type p53, were identified. Taken together, these results indicate that in this MMTV-Hras-driven salivary tumor model, the major effect of the p53 R172H mutant is due to the loss of wild-type p53 function, with little or no gain-of-function effect on tumorigenesis, which may be explained by the tissue- and tumor type-specific properties of this gain-of-function mutant of p53. PMID:25695772

  14. Twenty-four hour quantitative-EEG and in-vivo glutamate biosensor detects activity and circadian rhythm dependent biomarkers of pathogenesis in Mecp2 null mice

    PubMed Central

    Johnston, Michael V.; Ammanuel, Simon; O'Driscoll, Cliona; Wozniak, Amy; Naidu, Sakkubai; Kadam, Shilpa D.

    2014-01-01

    Mutations in the X-linked gene encoding methyl-CpG-binding protein 2 (Mecp2) cause most cases of Rett syndrome (RTT). Currently there is no cure for RTT. Abnormal EEGs are found in 100% of RTT cases and are associated with severe sleep dysfunction, the cause of which is not well understood. Mice deficient in MeCP2 protein have been studied and characterized for their neuropathological and behavioral deficits to better understand RTT. With the goal to study the non-ictal EEG correlates in symptomatic Mecp2 KO mice (Mecp2tm1.1Bird/y), and determine novel EEG biomarkers of their reported progressive neurodegeneration, we used 24 h video-EEG/EMG with synchronous in-vivo cortical glutamate biosensor in the frontal cortex. We scored the EEG for activity states and spectral analysis was performed to evaluate correlations to the synchronous extracellular glutamate fluctuations underlying Mecp2 inactivation as compared to WT. Significant alterations in sleep structure due to dark cycle-specific long wake states and poor quality of slow-wave sleep were associated with a significant increase in glutamate loads per activity cycle. The dynamics of the activity-state-dependent physiological rise and fall of glutamate indicative of glutamate homeostasis were significantly altered in the KO mice. Colorimetric quantitation of absolute glutamate levels in frontal cortex also indicated the presence of significantly higher levels in KO. This study for the first time found evidence of uncompensated sleep deprivation-like EEG biomarkers that were associated with glutamate homeostatic dysfunction in the Mecp2 KO mice. PMID:25018705

  15. Chloride secretion in the trachea of null cystic fibrosis mice: the effects of transfection with pTrial10-CFTR2.

    PubMed Central

    MacVinish, L J; Gill, D R; Hyde, S C; Mofford, K A; Evans, M J; Higgins, C F; Colledge, W H; Huang, L; Sorgi, F; Ratcliff, R; Cuthbert, A W

    1997-01-01

    1. An improved novel plasmid backbone, pTrial10, has been developed. We have used this vector to deliver the cDNA for the cystic fibrosis transmembrane conductance regulator (CFTR) to cells, both in vitro and in vivo, complexed with cationic liposomes. 2. Human 293 kidney epithelial cells (HEK 293) showed expression of an immunoprecipitable 165 kDa protein corresponding to CFTR when transfected in vitro with pTrial10-CFTR2, but not when the vector pTrial10 was used. 3. HEK 293 cells transfected with pTrial10-CFTR2, but not pTrial10, demonstrated a cAMP-dependent anion conductance, measured by fluorescence microscopy using a halide-sensitive probe, SPQ. 4. The CFTR-dependent, cAMP-sensitive chloride secretory response in murine tracheal epithelium could be measured if the calcium-dependent chloride secretory process was first maximally stimulated with a mixture of the Ca(2+)-ATPase inhibitor, TBHQ, and the calcium ionophore, A23187. With these conditions wild-type and CF-null (transgenic animals in which the cystic fibrosis (CF) gene has been disrupted so that no CFTR is produced) murine tracheas could be distinguished. The difference between the current elicited by forskolin in wild-type and CF tracheas was highly significantly different (P < 0.001), giving a CFTR-dependent current of 11.2 microA cm-2. 5. Transfection of the airways with pTrial10-CFTR2, but not pTrial10, significantly (P < 0.01) increased the CFTR-dependent chloride secretory current in CF tracheas. The degree of correction was greater when intra-tracheal installation rather than nasal insufflation was used to deliver the plasmids. Images Figure 1 Figure 2 PMID:9130164

  16. Anaplerotic Triheptanoin Diet Enhances Mitochondrial Substrate Use to Remodel the Metabolome and Improve Lifespan, Motor Function, and Sociability in MeCP2-Null Mice

    PubMed Central

    Li, Qun; Degano, Alicia L.; Penati, Judith; Zhuo, Justin; Roe, Charles R.; Ronnett, Gabriele V.

    2014-01-01

    Rett syndrome (RTT) is an autism spectrum disorder (ASD) caused by mutations in the X-linked MECP2 gene that encodes methyl-CpG binding protein 2 (MeCP2). Symptoms range in severity and include psychomotor disabilities, seizures, ataxia, and intellectual disability. Symptom onset is between 6-18 months of age, a critical period of brain development that is highly energy-dependent. Notably, patients with RTT have evidence of mitochondrial dysfunction, as well as abnormal levels of the adipokines leptin and adiponectin, suggesting overall metabolic imbalance. We hypothesized that one contributor to RTT symptoms is energy deficiency due to defective nutrient substrate utilization by the TCA cycle. This energy deficit would lead to a metabolic imbalance, but would be treatable by providing anaplerotic substrates to the TCA cycle to enhance energy production. We show that dietary therapy with triheptanoin significantly increased longevity and improved motor function and social interaction in male mice hemizygous for Mecp2 knockout. Anaplerotic therapy in Mecp2 knockout mice also improved indicators of impaired substrate utilization, decreased adiposity, increased glucose tolerance and insulin sensitivity, decreased serum leptin and insulin, and improved mitochondrial morphology in skeletal muscle. Untargeted metabolomics of liver and skeletal muscle revealed increases in levels of TCA cycle intermediates with triheptanoin diet, as well as normalizations of glucose and fatty acid biochemical pathways consistent with the improved metabolic phenotype in Mecp2 knockout mice on triheptanoin. These results suggest that an approach using dietary supplementation with anaplerotic substrate is effective in improving symptoms and metabolic health in RTT. PMID:25299635

  17. Plaque Size Is Decreased but M1 Macrophage Polarization and Rupture Related Metalloproteinase Expression Are Maintained after Deleting T-Bet in ApoE Null Mice

    PubMed Central

    Tsaousi, Aikaterini; Hayes, Elaine M.; Di Gregoli, Karina; Bond, Andrew R.; Bevan, Laura

    2016-01-01

    Background Thelper1 (Th1) lymphocytes have been previously implicated in atherosclerotic plaque growth but their role in plaque vulnerability to rupture is less clear. We investigated whether T-bet knockout that prevents Th1 lymphocyte differentiation modulates classical (M1) macrophage activation or production of matrix degrading metalloproteinases (MMPs) and their tissue inhibitors, TIMPs. Methods & Results We studied the effect of T-bet deletion in apolipoproteinE (ApoE) knockout mice fed a high fat diet (HFD) or normal chow diet (ND). Transcript levels of M1/M2 macrophage polarization markers, selected MMPs and TIMPs were measured by RT-qPCR in macrophages isolated from subcutaneous granulomas or in whole aortae. Immunohistochemistry of aortic sinus (AS) and brachiocephalic artery (BCA) plaques was conducted to quantify protein expression of the same factors. Deletion of T-bet decreased mRNA for the M1 marker NOS-2 in granuloma macrophages but levels of M2 markers (CD206, arginase-1 and Ym-1), MMPs-2, -9, -12, -13, -14 and -19 or TIMPs-1 to -3 were unchanged. No mRNA differences were observed in aortic extracts from mice fed a HFD for 12 weeks. Moreover, AS and BCA plaques were similarly sized between genotypes, and had similar areas stained for NOS-2, COX-2, MMP-12 and MMP-14 proteins. T-bet deletion increased MMP-13, MMP-14 and arginase-1 in AS plaques. After 35 weeks of ND, T-bet deletion reduced the size of AS and BCA plaques but there were no differences in the percentage areas stained for M1 or M2 markers, MMPs-12, -13, -14, or TIMP-3. Conclusions Absence of Th1 lymphocytes is associated with reduced plaque size in ApoE knockout mice fed a normal but not high fat diet. In either case, M1 macrophage polarization and expression of several MMPs related to plaque instability are either maintained or increased. PMID:26886778

  18. Anaplerotic triheptanoin diet enhances mitochondrial substrate use to remodel the metabolome and improve lifespan, motor function, and sociability in MeCP2-null mice.

    PubMed

    Park, Min Jung; Aja, Susan; Li, Qun; Degano, Alicia L; Penati, Judith; Zhuo, Justin; Roe, Charles R; Ronnett, Gabriele V

    2014-01-01

    Rett syndrome (RTT) is an autism spectrum disorder (ASD) caused by mutations in the X-linked MECP2 gene that encodes methyl-CpG binding protein 2 (MeCP2). Symptoms range in severity and include psychomotor disabilities, seizures, ataxia, and intellectual disability. Symptom onset is between 6-18 months of age, a critical period of brain development that is highly energy-dependent. Notably, patients with RTT have evidence of mitochondrial dysfunction, as well as abnormal levels of the adipokines leptin and adiponectin, suggesting overall metabolic imbalance. We hypothesized that one contributor to RTT symptoms is energy deficiency due to defective nutrient substrate utilization by the TCA cycle. This energy deficit would lead to a metabolic imbalance, but would be treatable by providing anaplerotic substrates to the TCA cycle to enhance energy production. We show that dietary therapy with triheptanoin significantly increased longevity and improved motor function and social interaction in male mice hemizygous for Mecp2 knockout. Anaplerotic therapy in Mecp2 knockout mice also improved indicators of impaired substrate utilization, decreased adiposity, increased glucose tolerance and insulin sensitivity, decreased serum leptin and insulin, and improved mitochondrial morphology in skeletal muscle. Untargeted metabolomics of liver and skeletal muscle revealed increases in levels of TCA cycle intermediates with triheptanoin diet, as well as normalizations of glucose and fatty acid biochemical pathways consistent with the improved metabolic phenotype in Mecp2 knockout mice on triheptanoin. These results suggest that an approach using dietary supplementation with anaplerotic substrate is effective in improving symptoms and metabolic health in RTT. PMID:25299635

  19. Hypoxanthine uptake by skeletal muscle microvascular endothelial cells from equilibrative nucleoside transporter 1 (ENT1)-null mice: effect of oxidative stress.

    PubMed

    Bone, D B J; Antic, M; Quinonez, D; Hammond, J R

    2015-03-01

    Adenosine is an endogenous regulator of vascular tone. This activity of adenosine is terminated by its uptake and metabolism by microvascular endothelial cells (MVEC). The predominant transporter involved is ENT1 (equilibrative nucleoside transporter subtype 1). MVEC also express the nucleobase transporter (ENBT1) which is involved in the cellular flux of adenosine metabolites such as hypoxanthine. Changes in either of these transport systems would impact the bioactivity of adenosine and its metabolism, including the formation of oxygen free radicals. MVEC isolated from skeletal muscle of ENT1(+/+) and ENT1(-/-) mice were subjected to oxidative stress induced by simulated ischemia/reperfusion or menadione. The functional activities of ENT1 and ENBT1 were assessed based on zero-trans influx kinetics of radiolabeled substrates. There was a reduction in the rate of ENBT1-mediated hypoxanthine uptake by ENT1(+/+) MVEC treated with menadione or after exposure to conditions that simulate ischemia/reperfusion. In both cases, the superoxide dismutase mimetic MnTMPyP attenuated the loss of ENBT1 activity, implicating superoxide radicals in the response. In contrast, MVEC isolated from ENT1(-/-) mice showed no reduction in ENBT1 activity upon treatment with menadione or simulated ischemia/reperfusion, but they did have a significantly higher level of catalase activity relative to ENT1(+/+) MVEC. These data suggest that ENBT1 activity is decreased in MVEC in response to the increased superoxide radical that is associated with ischemia/reperfusion injury. MVEC isolated from ENT1(-/-) mice do not show this reduction in ENBT1, possibly due to increased catalase activity. PMID:25448155

  20. Blockade of Platelet-Derived Growth Factor or Its Receptors Transiently Delays but Does Not Prevent Fibrous Cap Formation in ApoE Null Mice

    PubMed Central

    Kozaki, Koichi; Kaminski, Wolfgang E.; Tang, Jingjing; Hollenbach, Stan; Lindahl, Per; Sullivan, Carol; Yu, Jin-Chen; Abe, Keith; Martin, Paul J.; Ross, Russell; Betsholtz, Christer; Giese, Neill A.; Raines, Elaine W.

    2002-01-01

    Platelet-derived growth factor (PDGF) is a potent stimulant of smooth muscle cell migration and proliferation in culture. To test the role of PDGF in the accumulation of smooth muscle cells in vivo, we evaluated ApoE −/− mice that develop complex lesions of atherosclerosis. Fetal liver cells from PDGF-B-deficient embryos were used to replace the circulating cells of lethally irradiated ApoE −/− mice. One month after transplant, all monocytes in PDGF-B −/− chimeras are of donor origin (lack PDGF), and no PDGF-BB is detected in circulating platelets, primary sources of PDGF in lesions. Although lesion volumes are comparable in the PDGF-B +/+ and −/− chimeras at 35 weeks, lesions in PDGF-B −/− chimeras contain mostly macrophages, appear less mature, and have a reduced frequency of fibrous cap formation as compared with PDGF-B +/+ chimeras. However, after 45 weeks, smooth muscle cell accumulation in fibrous caps is indistinguishable in the two groups. Comparison of elicited peritoneal macrophages by RNase protection assay shows an altered cytokine and cytokine receptor profile in PDGF-B −/− chimeras. ApoE −/− mice were also treated for up to 50 weeks with a PDGF receptor antagonist that blocks all three PDGF receptor dimers. Blockade of the PDGF receptors similarly delays, but does not prevent, accumulation of smooth muscle and fibrous cap formation. Thus, elimination of PDGF-B from circulating cells or blockade of PDGF receptors does not appear sufficient to prevent smooth muscle accumulation in advanced lesions of atherosclerosis. PMID:12368212

  1. Peri-implantation lethality in mice carrying megabase-scale deletion on 5qc3.3 is caused by Exoc1 null mutation

    PubMed Central

    Mizuno, Seiya; Takami, Kohei; Daitoku, Yoko; Tanimoto, Yoko; Dinh, Tra Thi Huong; Mizuno-Iijima, Saori; Hasegawa, Yoshikazu; Takahashi, Satoru; Sugiyama, Fumihiro; Yagami, Ken-ichi

    2015-01-01

    We found a novel spontaneous mouse mutant with depigmentation in the ventral body, which we called White Spotting (WS) mouse. Genetic investigation revealed deletion of a > 1.2-Mb genomic region containing nine genes (Kit, Kdr, Srd5a3, Tmeme165, Clock, Pdcl2, Nmu, Exoc1, and Cep135). We designated this mutant allele KitWS. Interestingly, homozygous mutants (KitWS/WS) showed a peri-implantation lethal phenotype. Expression analyses of these nine genes in blastocysts suggested that Exoc1 was a prime candidate for this phenotype. We produced Exoc1 knockout mice, and the same peri-implantation lethal phenotype was seen in Exoc1−/− embryos. In addition, the polygenic effect without Exoc1 was investigated in genome-edited KitWE mice carrying the Mb-scale deletion induced by the CRISPR/Cas9 system. As KitWE/WE embryos did not exhibit the abnormal phenotype, which was seen in KitWS/WS. We concluded that peri-implantation lethality in KitWS/WS was caused by a monogenic defect of Exoc1. PMID:26346620

  2. Nivolumab and Urelumab Enhance Antitumor Activity of Human T Lymphocytes Engrafted in Rag2-/-IL2Rγnull Immunodeficient Mice.

    PubMed

    Sanmamed, Miguel F; Rodriguez, Inmaculada; Schalper, Kurt A; Oñate, Carmen; Azpilikueta, Arantza; Rodriguez-Ruiz, Maria E; Morales-Kastresana, Aizea; Labiano, Sara; Pérez-Gracia, Jose L; Martín-Algarra, Salvador; Alfaro, Carlos; Mazzolini, Guillermo; Sarno, Francesca; Hidalgo, Manuel; Korman, Alan J; Jure-Kunkel, Maria; Melero, Ignacio

    2015-09-01

    A current pressing need in cancer immunology is the development of preclinical model systems that are immunocompetent for the study of human tumors. Here, we report the development of a humanized murine model that can be used to analyze the pharmacodynamics and antitumor properties of immunostimulatory monoclonal antibodies (mAb) in settings where the receptors targeted by the mAbs are expressed. Human lymphocytes transferred into immunodeficient mice underwent activation and redistribution to murine organs, where they exhibited cell-surface expression of hCD137 and hPD-1. Systemic lymphocyte infiltrations resulted in a lethal CD4(+) T cell-mediated disease (xenograft-versus-host disease), which was aggravated when murine subjects were administered clinical-grade anti-hCD137 (urelumab) and anti-hPD-1 (nivolumab). In mice engrafted with human colorectal HT-29 carcinoma cells and allogeneic human peripheral blood mononuclear cells (PBMC), or with a patient-derived gastric carcinoma and PBMCs from the same patient, we found that coadministration of urelumab and nivolumab was sufficient to significantly slow tumor growth. Correlated with this result were increased numbers of activated human T lymphocytes producing IFNγ and decreased numbers of human regulatory T lymphocytes in the tumor xenografts, possibly explaining the efficacy of the therapeutic regimen. Our results offer a proof of concept for the use of humanized mouse models for surrogate efficacy and histology investigations of immune checkpoint drugs and their combinations. PMID:26113085

  3. CARDIOMYOPATHY AND WORSENED ISCHEMIC HEART FAILURE IN SM22-α CRE-MEDIATED NEUROPILIN-1 NULL MICE: DYSREGULATION OF PGC1α AND MITOCHONDRIAL HOMEOSTASIS

    PubMed Central

    Wang, Ying; Cao, Ying; Yamada, Satsuki; Thirunavukkarasu, Mahesh; Nin, Veronica; Joshi, Mandip; Rishi, Muhammed T.; Bhattacharya, Santanu; Camacho-Pereira, Juliana; Sharma, Anil K.; Shameer, Khader; Kocher, Jean-Pierre A.; Sanchez, Juan A; Wang, Enfeng; Hoeppner, Luke H.; Dutta, Shamit K.; Leof1, Edward B.; Shah, Vijay; Claffey, Kevin P.; Chini, Eduardo; Simons, Michael; Terzic, Andre; Maulik, Nilanjana; Mukhopadhyay, Debabrata

    2015-01-01

    Objective Neuropilin-1 (NRP-1) is a multi-domain membrane receptor involved in angiogenesis and development of neuronal circuits, however, the role of NRP-1 in cardiovascular pathophysiology remains elusive. Approach and Results In this study, we first observed that deletion of NRP-1 induced peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α) in cardiomyocytes (CMs) and vascular smooth muscle cells (VSMCs), which was accompanied by dysregulated cardiac mitochondrial accumulation and induction of cardiac hypertrophy- and stress-related markers. To investigate the role of NRP-1 in vivo, we generated mice lacking Nrp-1 in CMs and VSMCs (SM22-α-Nrp-1 KO), which exhibited decreased survival rates, developed cardiomyopathy and aggravated ischemia-induced heart failure. Mechanistically, we found that NRP-1 specifically controls PGC1α and PPARγ in CMs through crosstalk with Notch1 and Smad2 signaling pathways respectively. Moreover, SM22-α-Nrp-1 KO mice exhibited impaired physical activities and altered metabolite levels in serum, liver, and adipose tissues, as demonstrated by global metabolic profiling analysis. Conclusions Our findings provide new insights into the cardio-protective role of NRP-1 and its influence on global metabolism. PMID:25882068

  4. Increased Lung Ischemia-Reperfusion Injury in Aquaporin 1-Null Mice Is Mediated via Decreased Hypoxia-Inducible Factor 2α Stability.

    PubMed

    Ge, Haiyan; Zhu, Huili; Xu, Nuo; Zhang, Dan; Ou, Jiaxian; Wang, Guifang; Fang, Xiaocong; Zhou, Jian; Song, Yuanlin; Bai, Chunxue

    2016-06-01

    Aquaporin (AQP) 1, a water channel protein expressed widely in vascular endothelia, has been shown to regulate cell migration, angiogenesis, and organ regeneration. Even though its role in the pathogenesis of lung ischemia-reperfusion (IR) injury has been defined, the functional role of AQP1 during long-term IR resolution remains to be clarified. Here, we found that AQP1 expression was increased at late time points (7-14 d) after IR and colocalized with endothelial cell (EC) marker CD31. Compared with IR in wild-type mice, IR in Aqp1(-/-) mice had significantly enhanced leukocyte infiltration, collagen deposition, and microvascular permeability, as well as inhibited angiogenic factor expression. AQP1 knockdown repressed hypoxia-inducible factor (HIF)-2α protein stability. HIF-2α overexpression rescued the angiogenic factor expression in pulmonary microvascular ECs with AQP1 knockdown exposed to hypoxia-reoxygenation. Furthermore, AQP1 knockdown suppressed cellular viability and capillary tube formation, and enhanced permeability in pulmonary microvascular ECs, which were partly rescued by HIF-2α overexpression. Thus, this study demonstrates that AQP1 deficiency delays long-term IR resolution, partly through repressing angiogenesis mediated by destabilizing HIF-2α. These results suggest that AQP1 participates in long-term IR resolution, at least in part by promoting angiogenesis. PMID:26649797

  5. Brain propagation of transduced α-synuclein involves non-fibrillar protein species and is enhanced in α-synuclein null mice.

    PubMed

    Helwig, Michael; Klinkenberg, Michael; Rusconi, Raffaella; Musgrove, Ruth E; Majbour, Nour K; El-Agnaf, Omar M A; Ulusoy, Ayse; Di Monte, Donato A

    2016-03-01

    Aggregation and neuron-to-neuron transmission are attributes of α-synuclein relevant to its pathogenetic role in human synucleinopathies such as Parkinson's disease. Intraparenchymal injections of fibrillar α-synuclein trigger widespread propagation of amyloidogenic protein species via mechanisms that require expression of endogenous α-synuclein and, possibly, its structural corruption by misfolded conformers acting as pathological seeds. Here we describe another paradigm of long-distance brain diffusion of α-synuclein that involves inter-neuronal transfer of monomeric and/or oligomeric species and is independent of recruitment of the endogenous protein. Targeted expression of human α-synuclein was induced in the mouse medulla oblongata through an injection of viral vectors into the vagus nerve. Enhanced levels of intra-neuronal α-synuclein were sufficient to initiate its caudo-rostral diffusion that likely involved at least one synaptic transfer and progressively reached specific brain regions such as the locus coeruleus, dorsal raphae and amygdala in the pons, midbrain and forebrain. Transfer of human α-synuclein was compared in two separate lines of α-synuclein-deficient mice versus their respective wild-type controls and, interestingly, lack of endogenous α-synuclein expression did not counteract diffusion but actually resulted in a more pronounced and advanced propagation of exogenous α-synuclein. Self-interaction of adjacent molecules of human α-synuclein was detected in both wild-type and mutant mice. In the former, interaction of human α-synuclein with mouse α-synuclein was also observed and might have contributed to differences in protein transmission. In wild-type and α-synuclein-deficient mice, accumulation of human α-synuclein within recipient axons in the pons, midbrain and forebrain caused morphological evidence of neuritic pathology. Tissue sections from the medulla oblongata and pons were stained with different antibodies recognizing

  6. Ablating L-FABP in SCP-2/SCP-x null mice impairs bile acid metabolism and biliary HDL-cholesterol secretion

    PubMed Central

    Martin, Gregory G.; Atshaves, Barbara P.; Landrock, Kerstin K.; Landrock, Danilo; Storey, Stephen M.; Howles, Philip N.; Kier, Ann B.

    2014-01-01

    On the basis of their abilities to bind bile acids and/or cholesterol, the physiological role(s) of liver fatty acid-binding protein (L-FABP) and sterol carrier protein (SCP) 2/SCP-x (SCP-2/SCP-x) gene products in biliary bile acid and cholesterol formation was examined in gene-ablated male mice. L-FABP (LKO) or L-FABP/SCP-2/SCP-x [triple-knockout (TKO)] ablation markedly decreased hepatic bile acid concentration, while SCP-2/SCP-x [double-knockout (DKO)] ablation alone had no effect. In contrast, LKO increased biliary bile acid, while DKO and TKO had no effect on biliary bile acid levels. LKO and DKO also altered biliary bile acid composition to increase bile acid hydrophobicity. Furthermore, LKO and TKO decreased hepatic uptake and biliary secretion of high-density lipoprotein (HDL)-derived 22-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-23,24-bisnor-5-cholen-3β-ol (NBD-cholesterol), while DKO alone had no effect. Finally, LKO and, to a lesser extent, DKO decreased most indexes contributing to cholesterol solubility in biliary bile. These results suggest different, but complementary, roles for L-FABP and SCP-2/SCP-x in biliary bile acid and cholesterol formation. L-FABP appears to function more in hepatic retention of bile acids as well as hepatic uptake and biliary secretion of HDL-cholesterol. Conversely, SCP-2/SCP-x may function more in formation and biliary secretion of bile acid, with less impact on hepatic uptake or biliary secretion of HDL-cholesterol. PMID:25277800

  7. Ablating L-FABP in SCP-2/SCP-x null mice impairs bile acid metabolism and biliary HDL-cholesterol secretion.

    PubMed

    Martin, Gregory G; Atshaves, Barbara P; Landrock, Kerstin K; Landrock, Danilo; Storey, Stephen M; Howles, Philip N; Kier, Ann B; Schroeder, Friedhelm

    2014-12-01

    On the basis of their abilities to bind bile acids and/or cholesterol, the physiological role(s) of liver fatty acid-binding protein (L-FABP) and sterol carrier protein (SCP) 2/SCP-x (SCP-2/SCP-x) gene products in biliary bile acid and cholesterol formation was examined in gene-ablated male mice. L-FABP (LKO) or L-FABP/SCP-2/SCP-x [triple-knockout (TKO)] ablation markedly decreased hepatic bile acid concentration, while SCP-2/SCP-x [double-knockout (DKO)] ablation alone had no effect. In contrast, LKO increased biliary bile acid, while DKO and TKO had no effect on biliary bile acid levels. LKO and DKO also altered biliary bile acid composition to increase bile acid hydrophobicity. Furthermore, LKO and TKO decreased hepatic uptake and biliary secretion of high-density lipoprotein (HDL)-derived 22-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-23,24-bisnor-5-cholen-3β-ol (NBD-cholesterol), while DKO alone had no effect. Finally, LKO and, to a lesser extent, DKO decreased most indexes contributing to cholesterol solubility in biliary bile. These results suggest different, but complementary, roles for L-FABP and SCP-2/SCP-x in biliary bile acid and cholesterol formation. L-FABP appears to function more in hepatic retention of bile acids as well as hepatic uptake and biliary secretion of HDL-cholesterol. Conversely, SCP-2/SCP-x may function more in formation and biliary secretion of bile acid, with less impact on hepatic uptake or biliary secretion of HDL-cholesterol. PMID:25277800

  8. Thermogenic characterization of ghrelin receptor null mice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ghrelin is the only known circulating orexigenic hormone that increases food intake and promotes adiposity, and these physiological functions of ghrelin are mediated through its receptor growth hormone secretagogue receptor (GHS-R). Ghrelin/GHS-R signaling plays a crucial role in energy homeostasis....

  9. Radiant Temperature Nulling Radiometer

    NASA Technical Reports Server (NTRS)

    Ryan, Robert (Inventor)

    2003-01-01

    A self-calibrating nulling radiometer for non-contact temperature measurement of an object, such as a body of water, employs a black body source as a temperature reference, an optomechanical mechanism, e.g., a chopper, to switch back and forth between measuring the temperature of the black body source and that of a test source, and an infrared detection technique. The radiometer functions by measuring radiance of both the test and the reference black body sources; adjusting the temperature of the reference black body so that its radiance is equivalent to the test source; and, measuring the temperature of the reference black body at this point using a precision contact-type temperature sensor, to determine the radiative temperature of the test source. The radiation from both sources is detected by an infrared detector that converts the detected radiation to an electrical signal that is fed with a chopper reference signal to an error signal generator, such as a synchronous detector, that creates a precision rectified signal that is approximately proportional to the difference between the temperature of the reference black body and that of the test infrared source. This error signal is then used in a feedback loop to adjust the reference black body temperature until it equals that of the test source, at which point the error signal is nulled to zero. The chopper mechanism operates at one or more Hertz allowing minimization of l/f noise. It also provides pure chopping between the black body and the test source and allows continuous measurements.

  10. Designing with null flux coils

    SciTech Connect

    Davey, K.R.

    1997-09-01

    Null flux were suggested by Danby and Powell in the late 1960`s as a useful means for realizing induced lift with little drag. As an array of alternating magnets is translated past a set of null flux coils, the currents induced in these coils act to vertically center the magnets on those coils. At present, one Japanese MAGLEV system company and two American-based companies are employing either null flux or flux eliminating coils in their design for high speed magnetically levitated transportation. The principle question addressed in paper is: what is the proper choice of coil length to magnet length in a null flux system? A generic analysis in the time and frequency domain is laid out with the intent of showing the optimal design specification in terms of coil parameters.

  11. HLA-A*01:03, HLA-A*24:02, HLA-B*08:01, HLA-B*27:05, HLA-B*35:01, HLA-B*44:02, and HLA-C*07:01 monochain transgenic/H-2 class I null mice: novel versatile preclinical models of human T cell responses.

    PubMed

    Boucherma, Rachid; Kridane-Miledi, Hédia; Bouziat, Romain; Rasmussen, Michael; Gatard, Tanja; Langa-Vives, Francina; Lemercier, Brigitte; Lim, Annick; Bérard, Marion; Benmohamed, Lbachir; Buus, Søren; Rooke, Ronald; Lemonnier, François A

    2013-07-15

    We have generated a panel of transgenic mice expressing HLA-A*01:03, -A*24:02, -B*08:01, -B*27:05, -B*35:01, -B*44:02, or -C*07:01 as chimeric monochain molecules (i.e., appropriate HLA α1α2 H chain domains fused with a mouse α3 domain and covalently linked to human β2-microglobulin). Whereas surface expression of several transgenes was markedly reduced in recipient mice that coexpressed endogenous H-2 class I molecules, substantial surface expression of all human transgenes was observed in mice lacking H-2 class I molecules. In these HLA monochain transgenic/H-2 class I null mice, we observed a quantitative and qualitative restoration of the peripheral CD8(+) T cell repertoire, which exhibited a TCR diversity comparable with C57BL/6 WT mice. Potent epitope-specific, HLA-restricted, IFN-γ-producing CD8(+) T cell responses were generated against known reference T cell epitopes after either peptide or DNA immunization. HLA-wise, these new transgenic strains encompass a large proportion of individuals from all major human races and ethnicities. In combination with the previously created HLA-A*02:01 and -B*07:02 transgenic mice, the novel HLA transgenic mice described in this report should be a versatile preclinical animal model that will speed up the identification and optimization of HLA-restricted CD8(+) T cell epitopes of potential interest in various autoimmune human diseases and in preclinical evaluation of T cell-based vaccines. PMID:23776170

  12. Effect of amphetamine on extracellular concentrations of amino acids in striatum in neurotensin subtype 1 and 2 receptor null mice: a possible interaction between neurotensin receptors and amino acid systems for study of schizophrenia.

    PubMed

    Li, Zhimin; Liang, Yanqi; Boules, Mona; Gordillo, Andres; Richelson, Elliott

    2010-06-01

    Neurotensin (NT) is a tridecapeptide that acts as a neuromodulator in the central nervous system mainly through two NT receptors: NTS1 and NTS2. The present study was done to determine the roles of NTS1 and NTS2 on amino acid release in striatum with the use of NTS1 or NTS2 knockout ((-/-)) mice given d-amphetamine. Both NTS1(-/-) and NTS2(-/-) mice had lower extracellular concentrations of D-serine in striatum than did wild type (WT) mice. NTS2(-/-) but not NTS1(-/-) mice also had significantly lower basal concentrations of glutamate in striatum as compared to that for WT mice. Systemic administration of d-amphetamine (4 mg/kg, ip) increased glutamate release by 500% in WT mice, as compared to 300% in NTS2(-/-) mice, and 250% in NTS1(-/-) mice. Additionally, d-amphetamine injection caused a 4-fold increase in GABA release in both WT and NTS2(-/-) mice, but only a 2-fold increase in NTS1(-/-) mice. Therefore, NTS1 and NTS2 modulate basal release of D-serine and glutamate, and also d-amphetamine-induced GABA and glutamate release in striatum. These results provide further support for the involvement of NT receptors in the pathogenesis of schizophrenia and provide a better understanding of the imbalance of amino acid systems through investigation of a DA-based animal model. PMID:20193696

  13. On spinors and null vectors

    NASA Astrophysics Data System (ADS)

    Budinich, Marco

    2014-03-01

    We investigate the relations between spinors and null vectors in Clifford algebra of any dimension with particular emphasis on the conditions that a spinor must satisfy to be simple (also: pure). In particular, we prove: (i) a new property for null vectors: each of them bisects spinor space into two subspaces of equal size; (ii) that simple spinors form one-dimensional subspaces of spinor space; (iii) a necessary and sufficient condition for a spinor to be simple that generalizes a theorem of Cartan and Chevalley which becomes a corollary of this result. We also show how to write down easily the most general spinor with a given associated totally null plane. This paper is dedicated to the memory of my father Paolo Budinich who passed away in November 2013 not before transferring to me his enthusiasm for simple spinors.

  14. NULL convention floating point multiplier.

    PubMed

    Albert, Anitha Juliette; Ramachandran, Seshasayanan

    2015-01-01

    Floating point multiplication is a critical part in high dynamic range and computational intensive digital signal processing applications which require high precision and low power. This paper presents the design of an IEEE 754 single precision floating point multiplier using asynchronous NULL convention logic paradigm. Rounding has not been implemented to suit high precision applications. The novelty of the research is that it is the first ever NULL convention logic multiplier, designed to perform floating point multiplication. The proposed multiplier offers substantial decrease in power consumption when compared with its synchronous version. Performance attributes of the NULL convention logic floating point multiplier, obtained from Xilinx simulation and Cadence, are compared with its equivalent synchronous implementation. PMID:25879069

  15. NULL Convention Floating Point Multiplier

    PubMed Central

    Ramachandran, Seshasayanan

    2015-01-01

    Floating point multiplication is a critical part in high dynamic range and computational intensive digital signal processing applications which require high precision and low power. This paper presents the design of an IEEE 754 single precision floating point multiplier using asynchronous NULL convention logic paradigm. Rounding has not been implemented to suit high precision applications. The novelty of the research is that it is the first ever NULL convention logic multiplier, designed to perform floating point multiplication. The proposed multiplier offers substantial decrease in power consumption when compared with its synchronous version. Performance attributes of the NULL convention logic floating point multiplier, obtained from Xilinx simulation and Cadence, are compared with its equivalent synchronous implementation. PMID:25879069

  16. Proliferation, differentiation and apoptosis in connexin43-null osteoblasts

    NASA Technical Reports Server (NTRS)

    Furlan, F.; Lecanda, F.; Screen, J.; Civitelli, R.

    2001-01-01

    Osteoblasts are highly coupled by gap junctions formed primarily by connexin43 (Cx43). We have shown that interference with Cx43 expression or function disrupts transcriptional regulation of osteoblast genes, and that deletion of Cx43 in the mouse causes skeletal malformations, delayed mineralization, and osteoblast dysfunction. Here, we studied the mechanisms by which genetic deficiency of Cx43 alters osteoblast development. While cell proliferation rates were similar in osteoblastic cells derived from calvaria of Cx43-null and wild type mice, camptothecin-induced apoptosis was 3-fold higher in mutant compared to wild type osteoblasts. When grown in mineralizing medium, Cx43-null cells were able to produce mineralized matrix but it took one week longer to reach the same mineralization levels as in normal cells. Likewise, expression of alkaline phosphatase activity per cell--a marker of osteoblast differentiation--was maximal only 2 weeks later in Cx43-null relative to wild-type cells. These observations suggest that Cx43 is important for a normal and timely development of the osteoblastic phenotype. Delayed differentiation and increase programmed cell death may explain the skeletal phenotype of Cx43-null mice.

  17. Fracture characterisation using geoelectric null-arrays

    NASA Astrophysics Data System (ADS)

    Falco, Pierik; Negro, François; Szalai, Sándor; Milnes, Ellen

    2013-06-01

    The term "geoelectric null-array" is used for direct current electrode configurations yielding a potential difference of zero above a homogeneous half-space. This paper presents a comparative study of the behaviour of three null-arrays, midpoint null-array (MAN), Wenner-γ null-array and Schlumberger null-array in response to a fracture, both in profiling and in azimuthal mode. The main objective is to determine which array(s) best localise fractures or best identify their orientation. Forward modelling of the three null-arrays revealed that the Wenner-γ and Schlumberger null-arrays localise vertical fractures the most accurately, whilst the midpoint null-array combined with the Schlumberger null-array allows accurate orientation of a fracture. Numerical analysis then served as a basis to interpret the field results. Field test measurements were carried out above a quarry in Les Breuleux (Switzerland) with the three null-arrays and classical arrays. The results were cross-validated with quarry-wall geological mapping. In real field circumstances, the Wenner-γ null-array proved to be the most efficient and accurate in localising fractures. The orientations of the fractures according to the numerical results were most efficiently determined with the midpoint null-array, whilst the Schlumberger null-array adds accuracy to the results. This study shows that geoelectrical null-arrays are more suitable than classical arrays for the characterisation of fracture geometry.

  18. Behavioural signs of chronic back pain in the SPARC-null mouse

    PubMed Central

    Millecamps, Magali; Tajerian, Maral; Sage, E. Helene; Stone, Laura S

    2010-01-01

    Study Design SPARC-null mice were examined for behavioural signs of chronic low back and/or radicular pain. Objective To assess SPARC-null mice as a rodent model of chronic low back and/or radicular pain due to degenerative disc disease. Summary of Background Data Degeneration of intervertebral discs is a major cause of chronic low back and radicular pain in humans. Inactivation of the SPARC (Secreted Protein, Acidic and Rich in Cysteine, also known as osteonectin and BM-40) gene in mice results in premature intervertebral disc degeneration. The impact of disc degeneration on behavioural measures of chronic pain has not been evaluated in this model. Methods Cohorts of young and old (3 and 6–12 months, respectively) SPARC-null and wild-type control mice were screened for behavioural indices of low back and/or radiating pain. Sensitivity to mechanical, cold and heat stimuli, locomotor impairment, and movement-evoked hypersensitivity were determined. Animals were challenged with three analgesic agents with different mechanisms: morphine, dexamethasone, and gabapentin. Results SPARC-null mice showed signs of movement-evoked discomfort as early as 3 months of age. Hypersensitivity to cold stimuli on both the lower back and hindpaws developed with increasing age. SPARC-null mice had normal sensitivity to tactile and heat stimuli, and locomotor skills were not impaired. The hypersensitivity to cold was reversed by morphine, but not by dexamethasone or gabapentin. Conclusion SPARC-null mice display behavioural signs consistent with chronic low back and radicular pain that we attribute to intervertebral disc degeneration. We predict that the SPARC-null mouse is a useful model of chronic back pain due to degenerative disc disease. PMID:20714283

  19. Effects of Local Heart Irradiation in a Glutathione S-Transferase Alpha 4-Null Mouse Model

    PubMed Central

    Boerma, Marjan; Singh, Preeti; Sridharan, Vijayalakshmi; Tripathi, Preeti; Sharma, Sunil; Singh, Sharda P.

    2015-01-01

    Glutathione S-transferase alpha 4 (GSTA4-4) is one of the enzymes responsible for the removal of 4-hydroxynonenal (4-HNE), an electrophilic product of lipid peroxidation in cellular membranes during oxidative stress. 4-HNE is a direct activator of nuclear factor (erythroid-derived 2)-like 2 (Nrf2), a transcription factor with many target genes encoding antioxidant and anti-electrophile enzymes. We have previously shown that Gsta4-null mice on a 129/Sv background exhibited increased activity of Nrf2 in the heart. Here we examined the sensitivity of this Gsta4-null mouse model towards cardiac function and structure loss due to local heart irradiation. Male Gsta4-null and wild-type mice were exposed to a single X-ray dose of 18 Gy to the heart. Six months after irradiation, immunohistochemical staining for respiratory complexes 2 and 5 indicated that radiation exposure had caused most pronounced alterations in mitochondrial morphology in Gsta4-null mice. On the other hand, wild-type mice showed a decline in cardiac function and an increase in plasma levels of troponin-I, while no such changes were observed in Gsta4-null mice. Radiation-induced Nrf2-target gene expression only in Gsta4-null mice. In conclusion, although loss of GSTA4-4 led to enhanced susceptibility of cardiac mitochondria to radiation-induced loss of morphology, cardiac function was preserved in Gsta4-null mice. We propose that this protection against cardiac function loss may occur, at least in part, by upregulation of the Nrf2 pathway. PMID:26010708

  20. Nulling at the Keck Interferometer

    NASA Technical Reports Server (NTRS)

    Colavita, M. Mark; Serabyn, Gene; Wizinowich, Peter L.; Akeson, Rachel L.

    2006-01-01

    The nulling mode of the Keck Interferometer is being commissioned at the Mauna Kea summit. The nuller combines the two Keck telescope apertures in a split-pupil mode to both cancel the on-axis starlight and to coherently detect the residual signal. The nuller, working at 10 um, is tightly integrated with the other interferometer subsystems including the fringe and angle trackers, the delay lines and laser metrology, and the real-time control system. Since first 10 um light in August 2004, the system integration is proceeding with increasing functionality and performance, leading to demonstration of a 100:1 on-sky null in 2005. That level of performance has now been extended to observations with longer coherent integration times. An overview of the overall system is presented, with emphasis on the observing sequence, phasing system, and differences with respect to the V2 system, along with a presentation of some recent engineering data.

  1. Balloon Exoplanet Nulling Interferometer (BENI)

    NASA Technical Reports Server (NTRS)

    Lyon, Richard G.; Clampin, Mark; Woodruff, Robert A.; Vasudevan, Gopal; Ford, Holland; Petro, Larry; Herman, Jay; Rinehart, Stephen; Carpenter, Kenneth; Marzouk, Joe

    2009-01-01

    We evaluate the feasibility of using a balloon-borne nulling interferometer to detect and characterize exosolar planets and debris disks. The existing instrument consists of a 3-telescope Fizeau imaging interferometer with 3 fast steering mirrors and 3 delay lines operating at 800 Hz for closed-loop control of wavefront errors and fine pointing. A compact visible nulling interferometer is under development which when coupled to the imaging interferometer would in-principle allow deep suppression of starlight. We have conducted atmospheric simulations of the environment above 100,000 feet and believe balloons are a feasible path forward towards detection and characterization of a limited set of exoplanets and their debris disks. Herein we will discuss the BENI instrument, the balloon environment and the feasibility of such as mission.

  2. Null Arguments in German Child Language.

    ERIC Educational Resources Information Center

    Hamann, Cornelia

    1996-01-01

    Investigates the 10% to 20% null subject stage in 3-year-olds in Germany and shows that this stage, though long, is not final. Findings indicate that children in this phase use structures found neither in the state of early null subjects nor in adult German, namely, postverbal referential null subjects. Further study is proposed. (94 references)…

  3. Protection from oxidative and electrophilic stress in the Gsta4-null mouse heart

    PubMed Central

    Beneš, Helen; Vuong, Mai K.; Boerma, Marjan; McElhanon, Kevin E.; Siegel, Eric R.; Singh, Sharda P.

    2013-01-01

    4-hydroxynonenal (4-HNE) mediates many pathological effects of oxidative and electrophilic stress and signals to activate cytoprotective gene expression regulated by NF-E2-related factor 2 (Nrf2). By exhibiting very high levels of 4-HNE-conjugating activity, the murine glutathione transferase alpha 4 (GSTA4-4) helps regulate cellular 4-HNE levels. To examine the role of 4-HNE in vivo, we disrupted the murine Gsta4 gene. Gsta4-null mice exhibited no cardiac phenotype under normal conditions and no difference in cardiac 4-HNE level as compared to wild-type (WT) mice. We hypothesized that the Nrf2 pathway might contribute an important compensatory mechanism to remove excess cardiac 4-HNE in Gsta4-null mice. Cardiac nuclear extracts from Gsta4-null mice exhibited significantly higher Nrf2 binding to antioxidant-response elements (AREs). We also observed responses in critical Nrf2 target gene products: elevated Sod2, Cat, and Akr1b7 mRNA levels and significant increases in both cardiac anti-oxidant and anti-electrophile enzyme activities. Gsta4-null mice were less sensitive and maintained normal cardiac function following chronic doxorubicin (DOX) treatment, known to increase cardiac 4-HNE levels. Hence, in the absence of GSTA4-4 to modulate both physiological and pathological 4-HNE levels, the adaptive Nrf2 pathway may be primed to contribute to a preconditioned cardiac phenotype in the Gsta4-null mouse. PMID:23690225

  4. Visualization of the human CD4{sup +} T-cell response in humanized HLA-DR4-expressing NOD/Shi-scid/γc{sup null} (NOG) mice by retrogenic expression of the human TCR gene

    SciTech Connect

    Takahashi, Takeshi Katano, Ikumi; Ito, Ryoji; Ito, Mamoru

    2015-01-02

    Highlights: • β-Lactoglobulin (BLG) specific TCR genes were introduced to human HSC by retrovirus. • Human HSC with BLG-specific TCR were transplanted into NOG-HLA-DR4 I-A{sup −/−} mice. • BLG-specific TCR induced positive selection of thymocytes. • BLG-specific TCR positive CD4{sup +} T cells mediated immune responses in humanized mice. - Abstract: The development of severe immunodeficient mouse strains containing various human genes, including cytokines or HLA, has enabled the reconstitution of functional human immune systems after transplantation of human hematopoietic stem cells (HSC). Accumulating evidence has suggested that HLA-restricted antigen-specific human T-cell responses can be generated in these humanized mice. To directly monitor immune responses of human CD4{sup +} T cells, we introduced β-lactoglobulin (BLG)-specific T cell receptor (TCR) genes derived from CD4{sup +} T-cell clones of cow-milk allergy patients into HSCs, and subsequently transplanted them into NOG-HLA-DR4 transgenic/I-Aβ deficient mice (NOG-DR4/I-A{sup o}). In the thymus, thymocytes with BLG-specific TCR preferentially differentiated into CD4{sup +}CD8{sup −} single-positive cells. Adoptive transfer of mature CD4{sup +} T cells expressing the TCR into recipient NOG-DR4/I-A{sup o} mice demonstrated that human CD4{sup +} T cells proliferated in response to antigenic stimulation and produced IFN-γ in vivo, suggesting that functional T-cell reactions (especially Th1-skewed responses) were induced in humanized mice.

  5. Broken chiral symmetry on a null plane

    SciTech Connect

    Beane, Silas R.

    2013-10-15

    On a null-plane (light-front), all effects of spontaneous chiral symmetry breaking are contained in the three Hamiltonians (dynamical Poincaré generators), while the vacuum state is a chiral invariant. This property is used to give a general proof of Goldstone’s theorem on a null-plane. Focusing on null-plane QCD with N degenerate flavors of light quarks, the chiral-symmetry breaking Hamiltonians are obtained, and the role of vacuum condensates is clarified. In particular, the null-plane Gell-Mann–Oakes–Renner formula is derived, and a general prescription is given for mapping all chiral-symmetry breaking QCD condensates to chiral-symmetry conserving null-plane QCD condensates. The utility of the null-plane description lies in the operator algebra that mixes the null-plane Hamiltonians and the chiral symmetry charges. It is demonstrated that in a certain non-trivial limit, the null-plane operator algebra reduces to the symmetry group SU(2N) of the constituent quark model. -- Highlights: •A proof (the first) of Goldstone’s theorem on a null-plane is given. •The puzzle of chiral-symmetry breaking condensates on a null-plane is solved. •The emergence of spin-flavor symmetries in null-plane QCD is demonstrated.

  6. Disruptions of Sleep/Wake Patterns in the Stable Tubule Only Polypeptide (STOP) Null Mouse Model of Schizophrenia.

    PubMed

    Profitt, Maxine F; Deurveilher, Samuel; Robertson, George S; Rusak, Benjamin; Semba, Kazue

    2016-09-01

    Disruption of sleep/wake cycles is common in patients with schizophrenia and correlates with cognitive and affective abnormalities. Mice deficient in stable tubule only polypeptide (STOP) show cognitive, behavioral, and neurobiological deficits that resemble those seen in patients with schizophrenia, but little is known about their sleep phenotype. We characterized baseline sleep/wake patterns and recovery sleep following sleep deprivation in STOP null mice. Polysomnography was conducted in adult male STOP null and wild-type (WT) mice under a 12:12 hours light:dark cycle before, during, and after 6 hours of sleep deprivation during the light phase. At baseline, STOP null mice spent more time awake and less time in non-rapid eye movement sleep (NREMS) over a 24-hour period, with more frequent transitions between wake and NREMS, compared to WT mice, especially during the dark phase. The distributions of wake, NREMS and REMS across the light and the dark phases differed by genotype, and so did features of the electroencephalogram (EEG). Following sleep deprivation, both genotypes showed homeostatic increases in sleep duration, with no significant genotype differences in the initial compensatory increase in sleep intensity (EEG delta power). These results indicate that STOP null mice sleep less overall, and their sleep and wake periods are more fragmented than those of WT mice. These features in STOP null mice are consistent with the sleep patterns observed in patients with schizophrenia. PMID:26940700

  7. Visible Nulling Coronagraph Testbed Results

    NASA Technical Reports Server (NTRS)

    Lyon, Richard G.; Clampin, Mark; Melnick, Gary; Tolls, Volker; Woodruff, Robert; Vasudevan, Gopal; Rizzo, Maxime; Thompson, Patrick

    2009-01-01

    The Extrasolar Planetary Imaging Coronagraph (EPIC) is a NASA Astrophysics Strategic Mission Concept study and a proposed NASA Discovery mission to image and characterize extrasolar giant planets in orbits with semi-major axes between 2 and 10 AU. EPIC would provide insights into the physical nature of a variety of planets in other solar systems complimenting radial velocity (RV) and astrometric planet searches. It will detect and characterize the atmospheres of planets identified by radial velocity surveys, determine orbital inclinations and masses, characterize the atmospheres around A and F stars, observed the inner spatial structure and colors of inner Spitzer selected debris disks. EPIC would be launched to heliocentric Earth trailing drift-away orbit, with a 5-year mission lifetime. The starlight suppression approach consists of a visible nulling coronagraph (VNC) that enables starlight suppression in broadband light from 480-960 nm. To demonstrate the VNC approach and advance it's technology readiness we have developed a laboratory VNC and have demonstrated white light nulling. We will discuss our ongoing VNC work and show the latest results from the VNC testbed.

  8. Differential sensitivity of plasma carboxylesterase-null mice to parathion, chlorpyrifos and chlorpyrifos oxon, but not to diazinon, dichlorvos, diisopropylfluorophosphate, cresyl saligenin phosphate, cyclosarin thiocholine, tabun thiocholine, and carbofuran

    PubMed Central

    Duysen, Ellen G.; Cashman, John R.; Schopfer, Lawrence M.; Nachon, Florian; Masson, Patrick; Lockridge, Oksana

    2012-01-01

    Mouse blood contains four esterases that detoxify organophosphorus compounds: carboxylesterase, butyrylcholinesterase, acetylcholinesterase, and paraoxonase-1. In contrast human blood contains the latter three enzymes but not carboxylesterase. Organophosphorus compound toxicity is due to inhibition of acetylcholinesterase. Symptoms of intoxication appear after approximately 50% of the acetylcholinesterase is inhibited. However, complete inhibition of carboxylesterase and butyrylcholinesterase has no known effect on an animal’s well being. Paraoxonase hydrolyzes organophosphorus compounds and is not inhibited by them. Our goal was to determine the effect of plasma carboxylesterase deficiency on response to sublethal doses of 10 organophosphorus toxicants and one carbamate pesticide. Homozygous plasma carboxylesterase deficient ES1−/− mice and wild-type littermates were observed for toxic signs and changes in body temperature after treatment with a single sublethal dose of toxicant. Inhibition of plasma acetylcholinesterase, butyrylcholinesterase, and plasma carboxylesterase was measured. It was found that wild-type mice were protected from the toxicity of 12.5 mg/kg parathion applied subcutaneously. However, both genotypes responded similarly to paraoxon, cresyl saligenin phosphate, diisopropylfluorophosphate, diazinon, dichlorvos, cyclosarin thiocholine, tabun thiocholine, and carbofuran. An unexpected result was the finding that transdermal application of chlorpyrifos at 100 mg/kg and chlorpyrifos oxon at 14 mg/kg was lethal to wild-type but not to ES1−/− mice, showing that with this organochlorine, the presence of carboxylesterase was harmful rather than protective. It was concluded that carboxylesterase in mouse plasma protects from high toxicity agents, but the amount of carboxylesterase in plasma is too low to protect from low toxicity compounds that require high doses to inhibit acetylcholinesterase. PMID:22209767

  9. Parasitic interference in nulling interferometry

    NASA Astrophysics Data System (ADS)

    Matter, A.; Defrère, D.; Danchi, W. C.; Lopez, B.; Absil, O.

    2013-05-01

    Nulling interferometry aims to detect faint objects close to bright stars. Its principle is to produce a destructive interference along the line of sight so that the stellar flux is rejected, while the flux of the off-axis source can be transmitted. In practice, various instrumental perturbations can degrade the nulling performance. Any imperfection in phase, amplitude or polarization produces a spurious flux that leaks to the interferometer output and corrupts the transmitted off-axis flux. One of these instrumental perturbations is the crosstalk phenomenon, which occurs because of multiple parasitic reflections inside transmitting optics, and/or diffraction effects related to beam propagation along finite size optics. It can include a crosstalk of a beam with itself, and a mutual crosstalk between different beams. This can create a parasitic interference pattern, which degrades the intrinsic transmission map - or intensity response - of the interferometer. In this context, we describe how this instrumental effect impairs the performance of a Bracewell interferometer. A simple formalism is developed to derive the corresponding modified intensity response of the interferometer, as a function of the two parameters of interest: the crosstalk level (or contamination rate) and the phase shift between the primary and secondary - parasitic - beams. We then apply our mathematical approach to a few scientific cases, both analytically and using the GENIESIM simulation software, adapted to handle coherent crosstalk. Our results show that a coherent crosstalk level of about 1 per cent implies a 20 per cent drop of the signal-to-noise ratio at most. Careful attention should thus be paid to reduce the crosstalk level inside an interferometric instrument and ensure an instrumental stability that provides the necessary sensitivity through calibration procedures.

  10. Progesterone facilitates chromosome instability (aneuploidy) in p53 null normal mammary epithelial cells

    NASA Technical Reports Server (NTRS)

    Goepfert, T. M.; McCarthy, M.; Kittrell, F. S.; Stephens, C.; Ullrich, R. L.; Brinkley, B. R.; Medina, D.

    2000-01-01

    Mammary epithelial cells from p53 null mice have been shown recently to exhibit an increased risk for tumor development. Hormonal stimulation markedly increased tumor development in p53 null mammary cells. Here we demonstrate that mammary tumors arising in p53 null mammary cells are highly aneuploid, with greater than 70% of the tumor cells containing altered chromosome number and a mean chromosome number of 56. Normal mammary cells of p53 null genotype and aged less than 14 wk do not exhibit aneuploidy in primary cell culture. Significantly, the hormone progesterone, but not estrogen, increases the incidence of aneuploidy in morphologically normal p53 null mammary epithelial cells. Such cells exhibited 40% aneuploidy and a mean chromosome number of 54. The increase in aneuploidy measured in p53 null tumor cells or hormonally stimulated normal p53 null cells was not accompanied by centrosome amplification. These results suggest that normal levels of progesterone can facilitate chromosomal instability in the absence of the tumor suppressor gene, p53. The results support the emerging hypothesis based both on human epidemiological and animal model studies that progesterone markedly enhances mammary tumorigenesis.

  11. Optimal Beam Combiner Design for Nulling Interferometers

    NASA Astrophysics Data System (ADS)

    Guyon, Olivier; Mennesson, Bertrand; Serabyn, Eugene; Martin, Stefan

    2013-08-01

    A scheme to optimally design a beam combiner is discussed for any predetermined fixed geometry nulling interferometer aimed at detection and characterization of exoplanets with multiple telescopes or a single telescope (aperture masking). We show that considerably higher order nulls can be achieved with 1D (one-dimensional) interferometer geometries than possible with 2D (two-dimensional) geometries with the same number of apertures. Any 1D interferometer with N apertures can achieve a 2(N - 1)-order null, while the order of the deepest null for a random 2D aperture geometry interferometer is the order of the Nth term in the Taylor expansion of ei(x2+y2) around x = 0, y = 0 (2nd order null for N = 2,3 4th order null for N = 4,5,6). We also show that an optimal beam combiner for nulling interferometry relies on only 0 or π phase shifts. Examples of nulling interferometer designs are shown to illustrate these findings.

  12. Classical and Alternative Activation and Metalloproteinase Expression Occurs in Foam Cell Macrophages in Male and Female ApoE Null Mice in the Absence of T and B Lymphocytes

    PubMed Central

    Hayes, Elaine Mo; Tsaousi, Aikaterini; Di Gregoli, Karina; Jenkinson, S. Rhiannon; Bond, Andrew R.; Johnson, Jason L.; Bevan, Laura; Thomas, Anita C.; Newby, Andrew C.

    2014-01-01

    Background: Rupture of advanced atherosclerotic plaques accounts for most life-threatening myocardial infarctions. Classical (M1) and alternative (M2) macrophage activation could promote atherosclerotic plaque progression and rupture by increasing production of proteases, including matrix metalloproteinases (MMPs). Lymphocyte-derived cytokines may be essential for generating M1 and M2 phenotypes in plaques, although this has not been rigorously tested until now. Methods and results: We validated the expression of M1 markers (iNOS and COX-2) and M2 markers (arginase-1, Ym-1, and CD206) and then measured MMP mRNA levels in mouse macrophages during classical and alternative activation in vitro. We then compared mRNA expression of these genes ex vivo in foam cells from subcutaneous granulomas in fat-fed immune-competent ApoE knockout (KO) and immune-compromised ApoE/Rag-1 double-KO mice, which lack all T and B cells. Furthermore, we performed immunohistochemistry in subcutaneous granulomas and in aortic root and brachiocephalic artery atherosclerotic plaques to measure the extent of M1/M2 marker and MMP protein expression in vivo. Classical activation of mouse macrophages with bacterial lipopolysaccharide in vitro increased MMPs-13, -14, and -25 but decreased MMP-19 and TIMP-2 mRNA expressions. Alternative activation with IL-4 increased MMP-19 expression. Foam cells in subcutaneous granulomas expressed all M1/M2 markers and MMPs at ex vivo mRNA and in vivo protein levels, irrespective of Rag-1 genotype. There were also similar percentages of foam cell macrophages (FCMs) carrying M1/M2 markers and MMPs in atherosclerotic plaques from ApoE KO and ApoE/Rag-1 double-KO mice. Conclusion: Classical and alternative activation leads to distinct MMP expression patterns in mouse macrophages in vitro. M1 and M2 polarization in vivo occurs in the absence of T and B lymphocytes in either granuloma or plaque FCMs. PMID:25389425

  13. Nulling interferometry: symmetry requirements and experimental results

    NASA Astrophysics Data System (ADS)

    Serabyn, Eugene

    2000-07-01

    This paper provides a derivation from first principles of the stringent symmetry and stability requirements which deep stellar nulling demands, and also includes a brief status report on recent nulling results obtained with the Jet Propulsion Laboratory's fiber-coupled rotational-shearing interferometer. To date, the deepest transient nulls obtained (at red wavelengths) are 2 X 10-6 with a laser diode source, and 1.4 X 10-5 with a single- polarization thermal white-light source filtered to provide an 18% passband. In addition, both the laser and white light nulls have been stabilized to the 10-4 level. This visible wavelength laboratory nuller thus meets essentially all of the performance goals for the planned nulling experiment on board NASA's Space Interferometer Mission, with the sole exception of dual-polarization operation.

  14. Automatic null ellipsometry with an interferometer

    SciTech Connect

    Watkins, Lionel R.

    2009-11-10

    A new approach to automatic null ellipsometry is described in which the analyzer of a traditional polarizer compensator sample analyzer (PCSA) null ellipsometer is replaced with a heterodyne Michelson interferometer. One arm of this interferometer is modified such that it produces a fixed, linearly polarized reference beam, irrespective of the input polarization state. This beam is recombined interferometrically with the measurement beam and spatially separated into its p and s polarizations. The relative phase of the resulting temporal fringes is a linear function of the polarizer azimuthal angle P, and thus this component can be driven to its null position without iteration. Once at null, the azimuthal angle of the reflected, linearly polarized light is trivially determined from the relative amplitude of the fringes. Measurements made with this instrument on a native oxide film on a silicon wafer were in excellent agreement with those made with a traditional PCSA null ellipsometer.

  15. Nulling interferometry without achromatic phase shifters.

    PubMed

    Mieremet, Arjan L; Braat, Joseph J M

    2002-08-01

    In the infrared wavelength region, a typical star is approximately a million times brighter than the planet that surrounds it, which is a major problem when we attempt to detect exoplanets in a direct manner. Nulling interferometry is a technique that one can use to solve this problem by attenuating the stellar light and enhancing that of the planet. Generally, deep nulling is achieved by use of achromatic phase shifters (APSs). Unfortunately, the technology needed to build these APSs is not yet fully developed. We show that deep nulling can also be achieved by using delay lines only. We investigate the nulling depth as a function of the width of the wavelength interval and the number of telescopes. We also show that we can obtain nulling depths of less than 10(-6), which are required for exoplanet detection. Furthermore, we investigate the properties of the transmission map and make a comparison between our system and an APS system. PMID:12153105

  16. Characterization of the treefrog null allele

    SciTech Connect

    Guttman, S.I. . Dept. of Zoology)

    1990-12-01

    As part of the authors intensive year-long baseline ecological study, they characterized the degree of genetic polymorphism and heterozygosity in selected Feed Materials Production Center (FMPC) populations using electrophoretic techniques. These data are being used as an indicator of stress by comparing populations on and off the FMPC site. The current study was initiated to determine whether this GPI null allele is lethal, when homozygous, in spring peepers. Also, a sampling protocol was implemented to determine whether a linear effect occurs relative to the frequency of the null allele offsite and to determine the origination site of the null allele. 18 refs., 2 figs., 4 tabs.

  17. Interactions Between Nuclear receptor SHP and FOXA1 Maintain Oscillatory Homocysteine Homeostasis in Mice

    PubMed Central

    Tsuchiya, Hiroyuki; da Costa, Kerry-Ann; Lee, Sangmin; Renga, Barbara; Jaeschke, Hartmut; Yang, Zhihong; Orena, Stephen J.; Goedken, Michael J.; Zhang, Yuxia; Kong, B; Lebofsky, Margitta; Rudraiah, Swetha; Smalling, Rana; Guo, Grace; Fiorucci, Stefano; Zeisel, Steven H.; Wang, Li

    2015-01-01

    BACKGROUND & AIMS Hyperhomocysteinemia is often associated with liver and metabolic diseases. We studied nuclear receptors that mediate oscillatory control of homocysteine homeostasis in mice. METHODS We studied mice with disruptions in Nr0b2 (called SHP-null mice) Bhmt, or both genes (BHMT-null/SHP-null mice), along with mice with wild-type copies of these genes (controls). Hyperhomocysteinemia was induced by feeding mice alcohol (the NIAAA binge model) or chow diets along with water containing 0.18% DL-homocysteine. Some mice were placed on diets containing cholic acid (1%) or cholestyramine (2%), or high-fat diets (60%). Serum and livers were collected over a 24 hr light–dark cycle and analyzed by RNA-seq, metabolomic, and quantitative PCR, immunoblot, and chromatin immunoprecipitation assays. RESULTS SHP-null mice had altered timing in expression of genes that regulate homocysteine metabolism, compared with control mice. Oscillatory production of S-adenosylmethionine, betaine, choline, phosphocholine, glyceophosphocholine, cystathionine, cysteine, hydrogen sulfide, glutathione disulfide, and glutathione, differed between SHP-null mice and control mice. SHP inhibited transcriptional activation of Bhmt and Cth by FOXA1. Expression of Bhmt and Cth was decreased when mice were fed cholic acid but increased when they were placed on diets containing cholestyramine or high-fat content. Diets containing ethanol or homocysteine induced hyperhomocysteinemia and glucose intolerance in control but not SHP-null mice. In BHMT-null and BHMT-null/SHP-null mice fed a control liquid, lipid vacuoles were observed in livers. Ethanol feeding induced accumulation of macrovesicular lipid vacuoles to the greatest extent in BHMT-null and BHMT-null/SHP-null mice. CONCLUSIONS Disruption of Shp in mice alters timing of expression of genes that regulate homocysteine metabolism and the liver responses to ethanol and homocysteine. SHP inhibits the transcriptional activation of Bhmt and Cth

  18. Null-strut calculus. II. Dynamics

    SciTech Connect

    Kheyfets, A.; LaFave, N.J.; Miller, W.A. )

    1990-06-15

    In this paper, we continue from the preceding paper to develop a fully functional Regge calculus geometrodynamic algorithm from the null-strut-calculus construction. The developments discussed include (a) the identification of the Regge calculus analogue of the constraint and evolution equations on the null-strut lattice, (b) a description of the Minkowski solid geometry for the simplicial blocks of the null-strut lattice, (c) a description of the evolution algorithm for the geometrodynamic scheme and an analysis of its consistency, and (d) a presentation of the dynamical degrees of freedom for a simplicial hypersurface and the description of an initial-value prescription. To demonstrate qualitatively this new approach to geometrodynamics, we present the most simple application of null-strut calculus that we know of---the Friedmann cosmology using the three-boundary of a 600-cell simplicial polytope to model the simplicial hypersurface.

  19. Null structure groups in eleven dimensions

    SciTech Connect

    Cariglia, Marco; Mac Conamhna, Oisin A. P.

    2006-02-15

    We classify all the structure groups which arise as subgroups of the isotropy group (Spin(7)xR{sup 8})xR, of a single null Killing spinor in 11 dimensions. We construct the spaces of spinors fixed by these groups. We determine the conditions under which structure subgroups of the maximal null structure group (Spin(7)xR{sup 8})xR may also be embedded in SU(5), and hence the conditions under which a supersymmetric spacetime admits only null, or both timelike and null, Killing spinors. We discuss how this purely algebraic material will facilitate the direct analysis of the Killing spinor equation of 11 dimensional supergravity, and the classification of supersymmetric spacetimes therein.

  20. Premeiotic germ cell defect in seminiferous tubules of Atm-null testis

    SciTech Connect

    Takubo, Keiyo . E-mail: keiyot@gmail.com; Hirao, Atsushi; Ohmura, Masako; Azuma, Masaki; Arai, Fumio; Nagamatsu, Go; Suda, Toshio . E-mail: sudato@sc.itc.keio.ac.jp

    2006-12-29

    Lifelong spermatogenesis is maintained by coordinated sequential processes including self-renewal of stem cells, proliferation of spermatogonial cells, meiotic division, and spermiogenesis. It has been shown that ataxia telangiectasia-mutated (ATM) is required for meiotic division of the seminiferous tubules. Here, we show that, in addition to its role in meiosis, ATM has a pivotal role in premeiotic germ cell maintenance. ATM is activated in premeiotic spermatogonial cells and the Atm-null testis shows progressive degeneration. In Atm-null testicular cells, differing from bone marrow cells of Atm-null mice, reactive oxygen species-mediated p16{sup Ink4a} activation does not occur in Atm-null premeiotic germ cells, which suggests the involvement of different signaling pathways from bone marrow defects. Although Atm-null bone marrow undergoes p16{sup Ink4a}-mediated cellular senescence program, Atm-null premeiotic germ cells exhibited cell cycle arrest and apoptotic elimination of premeiotic germ cells, which is different from p16{sup Ink4a}-mediated senescence.

  1. On the Penrose inequality along null hypersurfaces

    NASA Astrophysics Data System (ADS)

    Mars, Marc; Soria, Alberto

    2016-06-01

    The null Penrose inequality, i.e. the Penrose inequality in terms of the Bondi energy, is studied by introducing a functional on surfaces and studying its properties along a null hypersurface Ω extending to past null infinity. We prove a general Penrose-type inequality which involves the limit at infinity of the Hawking energy along a specific class of geodesic foliations called Geodesic Asymptotically Bondi (GAB), which are shown to always exist. Whenever this foliation approaches large spheres, this inequality becomes the null Penrose inequality and we recover the results of Ludvigsen–Vickers (1983 J. Phys. A: Math. Gen. 16 3349–53) and Bergqvist (1997 Class. Quantum Grav. 14 2577–83). By exploiting further properties of the functional along general geodesic foliations, we introduce an approach to the null Penrose inequality called the Renormalized Area Method and find a set of two conditions which imply the validity of the null Penrose inequality. One of the conditions involves a limit at infinity and the other a restriction on the spacetime curvature along the flow. We investigate their range of applicability in two particular but interesting cases, namely the shear-free and vacuum case, where the null Penrose inequality is known to hold from the results by Sauter (2008 PhD Thesis Zürich ETH), and the case of null shells propagating in the Minkowski spacetime. Finally, a general inequality bounding the area of the quasi-local black hole in terms of an asymptotic quantity intrinsic of Ω is derived.

  2. Phase-only nulling for transmit antenna

    NASA Astrophysics Data System (ADS)

    Hussain, Moayyed A.; Yu, Kai-Bor

    1999-11-01

    This paper describes a technique for transmit antenna nulling for low-cost large sparse phased array radar system. Radar system described includes an array of elemental antennas, each with a transmit/receive (T/R) module. The T/R modules are operated at or near maximum output to achieve maximum CD-to-RF efficiency. A phase controller controls the phase shift, which are imparted by each module to its signal, to form a mainbeam and its associated sidelobes. A perturbation phase generator adds phase shifts computed, to form wide nulls in the sidelobe structure. The nulls are achieved at very minimal loss of gain, in the order of fraction of a dB. The speed of obtaining these nulls in real time allows a rapid steering of these nulls in a hostile environment. The thinned aperture allow designing a light weigh mobile system. In radar context, these nulls may be placed on a source of ground clutter, a set of jammers or a set of undesirable radio sources.

  3. Proof of the quantum null energy condition

    NASA Astrophysics Data System (ADS)

    Bousso, Raphael; Fisher, Zachary; Koeller, Jason; Leichenauer, Stefan; Wall, Aron C.

    2016-01-01

    We prove the quantum null energy condition (QNEC), a lower bound on the stress tensor in terms of the second variation in a null direction of the entropy of a region. The QNEC arose previously as a consequence of the quantum focusing conjecture, a proposal about quantum gravity. The QNEC itself does not involve gravity, so a proof within quantum field theory is possible. Our proof is somewhat nontrivial, suggesting that there may be alternative formulations of quantum field theory that make the QNEC more manifest. Our proof applies to free and super-renormalizable bosonic field theories, and to any points that lie on stationary null surfaces. An example is Minkowski space, where any point p and null vector ka define a null plane N (a Rindler horizon). Given any codimension-2 surface Σ that contains p and lies on N , one can consider the von Neumann entropy Sout of the quantum state restricted to one side of Σ . A second variation Sout'' can be defined by deforming Σ along N , in a small neighborhood of p with area A . The QNEC states that ⟨Tk k(p )⟩≥ℏ/2 π lim A →0 Sout''/A .

  4. Three-dimensional null point reconnection regimes

    SciTech Connect

    Priest, E. R.; Pontin, D. I.

    2009-12-15

    Recent advances in theory and computational experiments have shown the need to refine the previous categorization of magnetic reconnection at three-dimensional null points--points at which the magnetic field vanishes. We propose here a division into three different types, depending on the nature of the flow near the spine and fan of the null. The spine is an isolated field line which approaches the null (or recedes from it), while the fan is a surface of field lines which recede from it (or approach it). So-called torsional spine reconnection occurs when field lines in the vicinity of the fan rotate, with current becoming concentrated along the spine so that nearby field lines undergo rotational slippage. In torsional fan reconnection field lines near the spine rotate and create a current that is concentrated in the fan with a rotational flux mismatch and rotational slippage. In both of these regimes, the spine and fan are perpendicular and there is no flux transfer across spine or fan. The third regime, called spine-fan reconnection, is the most common in practice and combines elements of the previous spine and fan models. In this case, in response to a generic shearing motion, the null point collapses to form a current sheet that is focused at the null itself, in a sheet that locally spans both the spine and fan. In this regime the spine and fan are no longer perpendicular and there is flux transfer across both of them.

  5. Collagen VI deficiency reduces muscle pathology, but does not improve muscle function, in the γ-sarcoglycan-null mouse

    PubMed Central

    de Greef, Jessica C.; Hamlyn, Rebecca; Jensen, Braden S.; O'Campo Landa, Raul; Levy, Jennifer R.; Kobuke, Kazuhiro; Campbell, Kevin P.

    2016-01-01

    Muscular dystrophy is characterized by progressive skeletal muscle weakness and dystrophic muscle exhibits degeneration and regeneration of muscle cells, inflammation and fibrosis. Skeletal muscle fibrosis is an excessive deposition of components of the extracellular matrix including an accumulation of Collagen VI. We hypothesized that a reduction of Collagen VI in a muscular dystrophy model that presents with fibrosis would result in reduced muscle pathology and improved muscle function. To test this hypothesis, we crossed γ-sarcoglycan-null mice, a model of limb-girdle muscular dystrophy type 2C, with a Col6a2-deficient mouse model. We found that the resulting γ-sarcoglycan-null/Col6a2Δex5 mice indeed exhibit reduced muscle pathology compared with γ-sarcoglycan-null mice. Specifically, fewer muscle fibers are degenerating, fiber size varies less, Evans blue dye uptake is reduced and serum creatine kinase levels are lower. Surprisingly, in spite of this reduction in muscle pathology, muscle function is not significantly improved. In fact, grip strength and maximum isometric tetanic force are even lower in γ-sarcoglycan-null/Col6a2Δex5 mice than in γ-sarcoglycan-null mice. In conclusion, our results reveal that Collagen VI-mediated fibrosis contributes to skeletal muscle pathology in γ-sarcoglycan-null mice. Importantly, however, our data also demonstrate that a reduction in skeletal muscle pathology does not necessarily lead to an improvement of skeletal muscle function, and this should be considered in future translational studies. PMID:26908621

  6. Collagen VI deficiency reduces muscle pathology, but does not improve muscle function, in the γ-sarcoglycan-null mouse.

    PubMed

    de Greef, Jessica C; Hamlyn, Rebecca; Jensen, Braden S; O'Campo Landa, Raul; Levy, Jennifer R; Kobuke, Kazuhiro; Campbell, Kevin P

    2016-04-01

    Muscular dystrophy is characterized by progressive skeletal muscle weakness and dystrophic muscle exhibits degeneration and regeneration of muscle cells, inflammation and fibrosis. Skeletal muscle fibrosis is an excessive deposition of components of the extracellular matrix including an accumulation of Collagen VI. We hypothesized that a reduction of Collagen VI in a muscular dystrophy model that presents with fibrosis would result in reduced muscle pathology and improved muscle function. To test this hypothesis, we crossed γ-sarcoglycan-null mice, a model of limb-girdle muscular dystrophy type 2C, with a Col6a2-deficient mouse model. We found that the resulting γ-sarcoglycan-null/Col6a2Δex5 mice indeed exhibit reduced muscle pathology compared with γ-sarcoglycan-null mice. Specifically, fewer muscle fibers are degenerating, fiber size varies less, Evans blue dye uptake is reduced and serum creatine kinase levels are lower. Surprisingly, in spite of this reduction in muscle pathology, muscle function is not significantly improved. In fact, grip strength and maximum isometric tetanic force are even lower in γ-sarcoglycan-null/Col6a2Δex5 mice than in γ-sarcoglycan-null mice. In conclusion, our results reveal that Collagen VI-mediated fibrosis contributes to skeletal muscle pathology in γ-sarcoglycan-null mice. Importantly, however, our data also demonstrate that a reduction in skeletal muscle pathology does not necessarily lead to an improvement of skeletal muscle function, and this should be considered in future translational studies. PMID:26908621

  7. Impact of Nicotine Metabolism on Nicotine’s Pharmacological Effects and Behavioral Responses: Insights from a Cyp2a(4/5)bgs-Null Mouse

    PubMed Central

    Li, Lei; Jia, Kunzhi; Zhou, Xin; McCallum, Sarah E.; Hough, Lindsay B.

    2013-01-01

    Nicotine metabolism is believed to affect not only nicotine’s pharmacological effects but also nicotine addiction. As a key step toward testing this hypothesis, we have studied nicotine metabolism and nicotine’s pharmacological and behavioral effects in a novel knockout mouse model [named Cyp2a(4/5)bgs-null] lacking a number of cytochrome P450 genes known to be or possibly involved in nicotine metabolism, including two Cyp2a and all Cyp2b genes. We found that, compared with wild-type mice, the Cyp2a(4/5)bgs-null mice showed >90% decreases in hepatic microsomal nicotine oxidase activity in vitro, and in rates of systemic nicotine clearance in vivo. Further comparisons of nicotine metabolism between Cyp2a(4/5)bgs-null and Cyp2a5-null mice revealed significant roles of both CYP2A5 and CYP2B enzymes in nicotine clearance. Compared with the behavioral responses in wild-type mice, the decreases in nicotine metabolism in the Cyp2a(4/5)bgs-null mice led to prolonged nicotine-induced acute pharmacological effects, in that null mice showed enhanced nicotine hypothermia and antinociception. Furthermore, we found that the Cyp2a(4/5)bgs-null mice developed a preference for nicotine in a conditioned place preference test, a commonly used test of nicotine’s rewarding effects, at a nicotine dose that was 4-fold lower than what was required by wild-type mice. Thus, CYP2A/2B-catalyzed nicotine clearance affects nicotine’s behavioral response as well as its acute pharmacological effects in mice. This result provides direct experimental support of the findings of pharmacogenetic studies that suggest linkage between rates of nicotine metabolism and smoking behavior in humans. PMID:24045421

  8. Two roads to the null energy condition

    NASA Astrophysics Data System (ADS)

    Parikh, Maulik

    2015-11-01

    The null energy condition has sweeping consequences in general relativity. I argue here that it has been misunderstood as a property exclusively of matter, when in fact it arises only in a theory of both matter and gravity. I then derive an equivalent geometric formulation of the null energy condition from worldsheet string theory, where it arises beautifully as simple Einstein’s equations in two dimensions. But further, I show that this condition also has a thermodynamic origin, following from a local version of the second law of thermodynamics, applied to gravitational entropy. Thus, far from being an incidental property of matter, the validity of the null energy condition hints at the deep dual origins of gravity.

  9. Null surfaces in static space-times

    NASA Astrophysics Data System (ADS)

    Vollick, Dan N.

    2015-07-01

    In this paper I consider surfaces in a space-time with a Killing vector ξ α that is time-like and hypersurface-orthogonal on one side of the surface. The Killing vector may be either time-like or space-like on the other side of the surface. It has been argued that the surface is null if ξ α ξ α → 0 as the surface is approached from the static region. This implies that, in a coordinate system adapted to ξ, surfaces with g tt = 0 are null. In spherically symmetric space-times the condition g rr = 0 instead of g tt = 0 is sometimes used to locate null surfaces. In this paper I examine the arguments that lead to these two different criteria and show that both arguments are incorrect. A surface ξ = const has a normal vector whose norm is proportional to ξ α ξ α . This lead to the conclusion that surfaces with ξ α ξ α = 0 are null. However, the proportionality factor generally diverges when g tt = 0, leading to a different condition for the norm to be null. In static spherically symmetric space-times this condition gives g rr = 0, not g tt = 0. The problem with the condition g rr = 0 is that the coordinate system is singular on the surface. One can either use a nonsingular coordinate system or examine the induced metric on the surface to determine if it is null. By using these approaches it is shown that the correct criteria is g tt = 0. I also examine the condition required for the surface to be nonsingular.

  10. Characterization of the treefrog null allele, 1991

    SciTech Connect

    Guttman, S.I.

    1992-04-01

    Spring peeper (Hyla crucifer) tadpoles collected from the waste storage area during the Biological and Ecological Site Characterization of the Feed Materials Production Center (FEMP) in 1986 and 1987 appeared to be unique. A null (inactive) allele was found at the glucose phosphate isomerase enzyme locus in significant frequencies (approximately 20%) each year; this allele did not appear to occur in the offsite sample collected approximately 15km from the FEMP. Null alleles at this locus have not been reported in other amphibian populations; when they have been found in other organisms they have invariably been lethal in the homozygous condition.

  11. Null-strut calculus. I. Kinematics

    SciTech Connect

    Kheyfets, A.; LaFave, N.J.; Miller, W.A. )

    1990-06-15

    This paper describes the kinematics of null-strut calculus---a 3+1 Regge calculus approach to general relativity. We show how to model the geometry of spacetime with simplicial spacelike three-geometries (TET's) linked to earlier'' and later'' momentumlike lattice surfaces (TET{sup *}) entirely by light rays or null struts.'' These three-layered lattice spacetime geometries are defined and analyzed using combinatorial formulas for the structure of polytopes. The following paper in this series describes how these three-layered spacetime lattices are used to model spacetimes in full conformity with Einstein's theory of gravity.

  12. Null-broadening in a waveguide.

    PubMed

    Kim, J S; Hodgkiss, W S; Kuperman, W A; Song, H C

    2002-07-01

    Null-broadening, introduced in plane wave beamforming, is extended to an ocean waveguide in the context of matched field processing. The method is based on the minimum variance processor with white noise constraint and the distribution of fictitious sources using the theory of waveguide invariants. The proposed method is demonstrated in simulation as well as with data collected during the SWellEx-96 experiment. As another application, it is shown that the width of a null can be controlled in an adaptive time reversal mirror with a source-receive array. PMID:12141344

  13. Polarization nulling interferometry for exoplanet detection.

    PubMed

    Spronck, Julien; Pereira, Silvania F; Braat, Joseph J M

    2006-04-01

    We introduce a new concept of nulling interferometer without any achromatic device, using polarization properties of light. This type of interferometer should enable a high rejection ratio in a theoretically unlimited spectral band. We analyze several consequences of the proposed design, notably, the possibility of fast internal modulation. PMID:19516397

  14. A Philosophical Critique of Null Hypothesis Testing.

    ERIC Educational Resources Information Center

    Orey III, Michael A.; And Others

    1989-01-01

    An attempt is made to clarify the philosophical foundations of the debate over research methodology appropriate for psychology in particular and the utility of null hypothesis testing in general. The article also relates the debate to education and suggests that the debate is far from settled. (IAH)

  15. Current progress on TPFI nulling architectures at Jet Propulsion Laboratory

    NASA Technical Reports Server (NTRS)

    Gappinger, Robert O.; Wallace, J. Kent; Bartos, Randall D.; Macdonald, Daniel R.; Brown, Kenneth A.

    2005-01-01

    Infrared interferometric nulling is a promising technology for exoplanet detection. Nulling research for the Terrestrial Planet Finder Interferometer has been exploring a variety of interferometer architectures at the Jet Propulsion Laboratory (JPL).

  16. Perturbative gauge theory at null infinity

    NASA Astrophysics Data System (ADS)

    Adamo, Tim; Casali, Eduardo

    2015-06-01

    We describe a theory living on the null conformal boundary I of four-dimensional Minkowski space, the states of which include the radiative modes of Yang-Mills theory. The action of a Kac-Moody symmetry algebra on the correlators of these states leads to a Ward identity for asymptotic "large" gauge transformations which is equivalent to the soft gluon theorem. The subleading soft gluon behavior is also obtained from a Ward identity for charges acting as vector fields on the sphere of null generators of I . Correlation functions of the Yang-Mills states are shown to produce the full classical S-matrix of Yang-Mills theory. The model contains additional states arising from nonunitary gravitational degrees of freedom, indicating a relationship with the twistor string of Berkovits and Witten.

  17. Adaptive Nulling for the Terrestrial Planet Finder Interferometer

    NASA Technical Reports Server (NTRS)

    Peters, Robert D.; Lay, Oliver P.; Jeganathan, Muthu; Hirai, Akiko

    2006-01-01

    A description of adaptive nulling for Terrestrial Planet Finder Interferometer (TPFI) is presented. The topics include: 1) Nulling in TPF-I; 2) Why Do Adaptive Nulling; 3) Parallel High-Order Compensator Design; 4) Phase and Amplitude Control; 5) Development Activates; 6) Requirements; 7) Simplified Experimental Setup; 8) Intensity Correction; and 9) Intensity Dispersion Stability. A short summary is also given on adaptive nulling for the TPFI.

  18. Starlight Nulling Technology at the Jet Propulsion Laboratory

    NASA Technical Reports Server (NTRS)

    Martin, Stefan

    2007-01-01

    The current interests in extra-solar planet detection and space-based and ground-based interferometry for astronomical observations has led to the development of a number of nulling instrument designs at the Jet Propulsion Laboratory (JPL) and elsewhere. This paper summarizes briefly JPL's efforts in nulling interferometry to date and consists of illustrations of some key nulling activities. Basic layouts of nulling testbeds are described and key applications discussed.

  19. Optimized Null Model for Protein Structure Networks

    PubMed Central

    Lappe, Michael; Pržulj, Nataša

    2009-01-01

    Much attention has recently been given to the statistical significance of topological features observed in biological networks. Here, we consider residue interaction graphs (RIGs) as network representations of protein structures with residues as nodes and inter-residue interactions as edges. Degree-preserving randomized models have been widely used for this purpose in biomolecular networks. However, such a single summary statistic of a network may not be detailed enough to capture the complex topological characteristics of protein structures and their network counterparts. Here, we investigate a variety of topological properties of RIGs to find a well fitting network null model for them. The RIGs are derived from a structurally diverse protein data set at various distance cut-offs and for different groups of interacting atoms. We compare the network structure of RIGs to several random graph models. We show that 3-dimensional geometric random graphs, that model spatial relationships between objects, provide the best fit to RIGs. We investigate the relationship between the strength of the fit and various protein structural features. We show that the fit depends on protein size, structural class, and thermostability, but not on quaternary structure. We apply our model to the identification of significantly over-represented structural building blocks, i.e., network motifs, in protein structure networks. As expected, choosing geometric graphs as a null model results in the most specific identification of motifs. Our geometric random graph model may facilitate further graph-based studies of protein conformation space and have important implications for protein structure comparison and prediction. The choice of a well-fitting null model is crucial for finding structural motifs that play an important role in protein folding, stability and function. To our knowledge, this is the first study that addresses the challenge of finding an optimized null model for RIGs, by

  20. Null conformal Killing-Yano tensors and Birkhoff theorem

    NASA Astrophysics Data System (ADS)

    Ferrando, Joan Josep; Sáez, Juan Antonio

    2016-04-01

    We study the space-times admitting a null conformal Killing-Yano tensor whose divergence defines a Killing vector. We analyze the similarities and differences with the recently studied non null case (Ferrando and Sáez in Gen Relativ Gravit 47:1911, 2015). The results by Barnes concerning the Birkhoff theorem for the case of null orbits are analyzed and generalized.

  1. Toroidally symmetric plasma vortex at tokamak divertor null point

    NASA Astrophysics Data System (ADS)

    Umansky, M. V.; Ryutov, D. D.

    2016-03-01

    Reduced MHD equations are used for studying toroidally symmetric plasma dynamics near the divertor null point. Numerical solution of these equations exhibits a plasma vortex localized at the null point with the time-evolution defined by interplay of the curvature drive, magnetic restoring force, and dissipation. Convective motion is easier to achieve for a second-order null (snowflake) divertor than for a regular x-point configuration, and the size of the convection zone in a snowflake configuration grows with plasma pressure at the null point. The trends in simulations are consistent with tokamak experiments which indicate the presence of enhanced transport at the null point.

  2. Magnetic Null Points in Kinetic Simulations of Space Plasmas

    NASA Astrophysics Data System (ADS)

    Olshevsky, Vyacheslav; Deca, Jan; Divin, Andrey; Peng, Ivy Bo; Markidis, Stefano; Innocenti, Maria Elena; Cazzola, Emanuele; Lapenta, Giovanni

    2016-03-01

    We present a systematic attempt to study magnetic null points and the associated magnetic energy conversion in kinetic particle-in-cell simulations of various plasma configurations. We address three-dimensional simulations performed with the semi-implicit kinetic electromagnetic code iPic3D in different setups: variations of a Harris current sheet, dipolar and quadrupolar magnetospheres interacting with the solar wind, and a relaxing turbulent configuration with multiple null points. Spiral nulls are more likely created in space plasmas: in all our simulations except lunar magnetic anomaly (LMA) and quadrupolar mini-magnetosphere the number of spiral nulls prevails over the number of radial nulls by a factor of 3-9. We show that often magnetic nulls do not indicate the regions of intensive energy dissipation. Energy dissipation events caused by topological bifurcations at radial nulls are rather rare and short-lived. The so-called X-lines formed by the radial nulls in the Harris current sheet and LMA simulations are rather stable and do not exhibit any energy dissipation. Energy dissipation is more powerful in the vicinity of spiral nulls enclosed by magnetic flux ropes with strong currents at their axes (their cross sections resemble 2D magnetic islands). These null lines reminiscent of Z-pinches efficiently dissipate magnetic energy due to secondary instabilities such as the two-stream or kinking instability, accompanied by changes in magnetic topology. Current enhancements accompanied by spiral nulls may signal magnetic energy conversion sites in the observational data.

  3. System and Method for Null-Lens Wavefront Sensing

    NASA Technical Reports Server (NTRS)

    Hill, Peter C. (Inventor); Thompson, Patrick L. (Inventor); Aronstein, David L. (Inventor); Bolcar, Matthew R. (Inventor); Smith, Jeffrey S. (Inventor)

    2015-01-01

    A method of measuring aberrations in a null-lens including assembly and alignment aberrations. The null-lens may be used for measuring aberrations in an aspheric optic with the null-lens. Light propagates from the aspheric optic location through the null-lens, while sweeping a detector through the null-lens focal plane. Image data being is collected at locations about said focal plane. Light is simulated propagating to the collection locations for each collected image. Null-lens aberrations may extracted, e.g., applying image-based wavefront-sensing to collected images and simulation results. The null-lens aberrations improve accuracy in measuring aspheric optic aberrations.

  4. Displacing Unpredictable Nulls in Antenna Radiation Patterns

    NASA Technical Reports Server (NTRS)

    Lux, James; Schaefer, Mark

    2005-01-01

    A method of maintaining radio communication despite the emergence of unpredictable fades and nulls in the radiation pattern of an antenna has been proposed. The method was originally intended to be applied in the design and operation of a radio antenna aboard a robotic exploratory vehicle on a remote planet during communication with a spacecraft in orbit around the planet. The method could also be applied in similar terrestrial situations for example, radio communication between two ground vehicles or between a ground vehicle and an aircraft or spacecraft. The method is conceptually simple, is readily adaptable to diverse situations, and can be implemented without adding greatly to the weight, cost, power demand, or complexity of a system to which it may be applied. The unpredictable fades and nulls in an antenna radiation pattern arise because of electromagnetic interactions between the antenna and other objects within the near field of the antenna (basically, objects within a distance of a few wavelengths). These objects can include general vehicle components, masts, robotic arms, other antennas, the ground, and nearby terrain features. Figure 1 presents representative plots of signal strength versus time during a typical pass of a spacecraft or aircraft through the far field of such an antenna, showing typical nulls and fades caused by nearby objects. The traditional approach to ensuring reliability of communication in the presence of deep fades calls for increasing the effective transmitter power and/or reducing the receiver noise figure at the affected ground vehicle, possibly in combination with appropriate redesign of the equipment at the spacecraft or aircraft end of the communication link. These solutions can be expensive and/or risky and, depending on the application, can add significantly to weight, cost, and power demand. The proposed method entails none of these disadvantages.

  5. Null generation using discs on a reflector

    NASA Astrophysics Data System (ADS)

    Rudisill, M. D.

    1984-12-01

    It has been shown possible experimentally to produce nulls in the pattern of a prime focus reflector antenna using discs mounted on the dish. A model of this antenna system is developed to evaluate optimal configurations and ideal performance. Aperture integration is the method of analysis used. Discs' effects are modeled as a phase shift on the aperture. No secondary effects, such as diffraction, are considered. Based on the model developed, guidelines are presented for antenna design. A computer code was written to implement the model and a prediction of antenna the system's performance is presented.

  6. Null Energy Condition in Dynamic Wormholes

    SciTech Connect

    Hochberg, D.; Visser, M.

    1998-07-01

    We extend previous proofs that violations of the null energy condition are a generic and universal feature of traversable wormholes to completely nonsymmetric time-dependent wormholes. We show that the analysis can be phrased purely in terms of local geometry at and near the wormhole throat, and we do not have to make any technical assumptions about asymptotic flatness or other global properties. A key aspect of the analysis is the demonstration that time-dependent wormholes have {ital two} throats, one for each direction through the wormhole, and that the two throats coalesce only for the case of a static wormhole. {copyright} {ital 1998} {ital The American Physical Society}

  7. Polyhedra in spacetime from null vectors

    NASA Astrophysics Data System (ADS)

    Neiman, Yasha

    2014-01-01

    We consider convex spacelike polyhedra oriented in the Minkowski space. These are the classical analogues of spinfoam intertwiners. We point out a parametrization of these shapes using null face normals, with no constraints or redundancies. Our construction is dimension-independent. In 3+1d, it provides the spacetime picture behind a well-known property of the loop quantum gravity intertwiner space in spinor form, namely that the closure constraint is always satisfied after some SL(2, C) rotation. As a simple application of our variables, we incorporate them in a 4-simplex action that reproduces the large-spin behavior of the Barrett-Crane vertex amplitude.

  8. Comprehensive Analysis of the 16p11.2 Deletion and Null Cntnap2 Mouse Models of Autism Spectrum Disorder.

    PubMed

    Brunner, Daniela; Kabitzke, Patricia; He, Dansha; Cox, Kimberly; Thiede, Lucinda; Hanania, Taleen; Sabath, Emily; Alexandrov, Vadim; Saxe, Michael; Peles, Elior; Mills, Alea; Spooren, Will; Ghosh, Anirvan; Feliciano, Pamela; Benedetti, Marta; Luo Clayton, Alice; Biemans, Barbara

    2015-01-01

    Autism spectrum disorder comprises several neurodevelopmental conditions presenting symptoms in social communication and restricted, repetitive behaviors. A major roadblock for drug development for autism is the lack of robust behavioral signatures predictive of clinical efficacy. To address this issue, we further characterized, in a uniform and rigorous way, mouse models of autism that are of interest because of their construct validity and wide availability to the scientific community. We implemented a broad behavioral battery that included but was not restricted to core autism domains, with the goal of identifying robust, reliable phenotypes amenable for further testing. Here we describe comprehensive findings from two known mouse models of autism, obtained at different developmental stages, using a systematic behavioral test battery combining standard tests as well as novel, quantitative, computer-vision based systems. The first mouse model recapitulates a deletion in human chromosome 16p11.2, found in 1% of individuals with autism. The second mouse model harbors homozygous null mutations in Cntnap2, associated with autism and Pitt-Hopkins-like syndrome. Consistent with previous results, 16p11.2 heterozygous null mice, also known as Del(7Slx1b-Sept1)4Aam weighed less than wild type littermates displayed hyperactivity and no social deficits. Cntnap2 homozygous null mice were also hyperactive, froze less during testing, showed a mild gait phenotype and deficits in the three-chamber social preference test, although less robust than previously published. In the open field test with exposure to urine of an estrous female, however, the Cntnap2 null mice showed reduced vocalizations. In addition, Cntnap2 null mice performed slightly better in a cognitive procedural learning test. Although finding and replicating robust behavioral phenotypes in animal models is a challenging task, such functional readouts remain important in the development of therapeutics and we

  9. Comprehensive Analysis of the 16p11.2 Deletion and Null Cntnap2 Mouse Models of Autism Spectrum Disorder

    PubMed Central

    He, Dansha; Cox, Kimberly; Thiede, Lucinda; Hanania, Taleen; Sabath, Emily; Alexandrov, Vadim; Saxe, Michael; Peles, Elior; Mills, Alea; Spooren, Will; Ghosh, Anirvan; Feliciano, Pamela; Benedetti, Marta; Luo Clayton, Alice; Biemans, Barbara

    2015-01-01

    Autism spectrum disorder comprises several neurodevelopmental conditions presenting symptoms in social communication and restricted, repetitive behaviors. A major roadblock for drug development for autism is the lack of robust behavioral signatures predictive of clinical efficacy. To address this issue, we further characterized, in a uniform and rigorous way, mouse models of autism that are of interest because of their construct validity and wide availability to the scientific community. We implemented a broad behavioral battery that included but was not restricted to core autism domains, with the goal of identifying robust, reliable phenotypes amenable for further testing. Here we describe comprehensive findings from two known mouse models of autism, obtained at different developmental stages, using a systematic behavioral test battery combining standard tests as well as novel, quantitative, computer-vision based systems. The first mouse model recapitulates a deletion in human chromosome 16p11.2, found in 1% of individuals with autism. The second mouse model harbors homozygous null mutations in Cntnap2, associated with autism and Pitt-Hopkins-like syndrome. Consistent with previous results, 16p11.2 heterozygous null mice, also known as Del(7Slx1b-Sept1)4Aam weighed less than wild type littermates displayed hyperactivity and no social deficits. Cntnap2 homozygous null mice were also hyperactive, froze less during testing, showed a mild gait phenotype and deficits in the three-chamber social preference test, although less robust than previously published. In the open field test with exposure to urine of an estrous female, however, the Cntnap2 null mice showed reduced vocalizations. In addition, Cntnap2 null mice performed slightly better in a cognitive procedural learning test. Although finding and replicating robust behavioral phenotypes in animal models is a challenging task, such functional readouts remain important in the development of therapeutics and we

  10. A Nulling Coronagraph for TPF-C

    NASA Technical Reports Server (NTRS)

    Shao, Michael; Levine, Bruce Martin; Wallace, James Kent; Orton, Glenn S.; Schmidtlin, Edouard; Lane, Benjamin F.; Seager, Sara; Tolls, Volker; Lyon, Richard G.; Samuele, Rocco; Tenerelli, Domenick J.; Woodruff, Robert; Ge, Jian

    2006-01-01

    The nulling coronagraph is one of 5 instrument concepts selected by NASA for study for potential use in the TPF-C mission. This concept for extreme starlight suppression has two major components, a nulling interferometer to suppress the starlight to 10(sup -10) per airy spot within 2 (lamda)/D of the star, and a calibration interferometer to measure the residual scattered starlight. The ability to work at 2 (lamda)/D dramatically improves the science throughput of a space based coronagraph like TPF-C. The calibration interferometer is an equally important part of the starlight suppression system. It measures the measures the wavefront of the scattered starlight with very high SNR, to 0.05nm in less than 5 minutes on a 5mag star. In addition, the post coronagraph wavefront sensor will be used to measure the residual scattered light after the coronagraph and subtract it in post processing to 12x10(sup -11) to enable detection of an Earthlike planet with a SNR of 510.

  11. Exome sequencing identified null mutations in LOXL3 associated with early-onset high myopia

    PubMed Central

    Li, Jiali; Gao, Bei; Xiao, Xueshan; Li, Shiqiang; Jia, Xiaoyun; Sun, Wenmin; Guo, Xiangming

    2016-01-01

    Purpose To identify null mutations in novel genes associated with early-onset high myopia using whole exome sequencing. Methods Null mutations, including homozygous and compound heterozygous truncations, were selected from whole exome sequencing data for 298 probands with early-onset high myopia. These data were compared with those of 507 probands with other forms of eye diseases. Null mutations specific to early-onset high myopia were considered potential candidates. Candidate mutations were confirmed with Sanger sequencing and were subsequently evaluated in available family members and 480 healthy controls. Results A homozygous frameshift mutation (c.39dup; p.L14Afs*21) and a compound heterozygous frameshift mutation (c.39dup; p.L14Afs*21 and c.594delG; p.Q199Kfs*35) in LOXL3 were separately identified in two of the 298 probands with early-onset high myopia. These mutations were confirmed with Sanger sequencing and were not detected in 1,974 alleles of the controls from the same region (507 individuals with other conditions and 480 healthy control individuals). These two probands were singleton cases, and their parents had only heterozygous mutations. A homozygous missense mutation in LOXL3 was recently reported in a consanguineous family with Stickler syndrome. Conclusions Our results suggest that null mutations in LOXL3 are likely associated with autosomal recessive early-onset high myopia. LOXL3 is a potential candidate gene for high myopia, but this possibility should be confirmed in additional studies. LOXL3 null mutations in human beings are not lethal, providing a phenotype contrary to that in mice. PMID:26957899

  12. Off-Axis Nulling Transfer Function Measurement: A First Assessment

    NASA Technical Reports Server (NTRS)

    Vedova, G. Dalla; Menut, J.-L.; Millour, F.; Petrov, R.; Cassaing, F.; Danchi, W. C.; Jacquinod, S.; Lhome, E.; Lopez, B.; Lozi, J.; Marcotto, A.; Parisot, J.; Reess, J.-M.

    2013-01-01

    We want to study a polychromatic inverse problem method with nulling interferometers to obtain information on the structures of the exozodiacal light. For this reason, during the first semester of 2013, thanks to the support of the consortium PERSEE, we launched a campaign of laboratory measurements with the nulling interferometric test bench PERSEE, operating with 9 spectral channels between J and K bands. Our objective is to characterise the transfer function, i.e. the map of the null as a function of wavelength for an off-axis source, the null being optimised on the central source or on the source photocenter. We were able to reach on-axis null depths better than 10(exp -4). This work is part of a broader project aiming at creating a simulator of a nulling interferometer in which typical noises of a real instrument are introduced. We present here our first results.

  13. Findings from a Three Year Survey of Coronal Null Points

    NASA Astrophysics Data System (ADS)

    Freed, Michael; Longcope, Dana; McKenzie, David Eugene

    2014-06-01

    We report the findings from a comprehensive coronal magnetic null point survey created by Potential Field Source Surface (PFSS) modeling & Solar Dynamic Observatory/Atmospheric Imaging Assembly (SDO/AIA) observations. Locations of magnetic null points in the corona were predicted from the PFSS model from Carrington Rotation 2098 to 2139 and manually compared to contrast enhanced SDO/AIA images in 171 angstroms. Statistical results will be presented that illustrate the characteristics associated with the observed and predicted null points. These characteristics include the radial & latitudinal distribution; eigenvalues associated with null point structure; and the effect spine orientation has on observability.

  14. Nulling Infrared Radiometer for Measuring Temperature

    NASA Technical Reports Server (NTRS)

    Ryan, Robert

    2003-01-01

    A nulling, self-calibrating infrared radiometer is being developed for use in noncontact measurement of temperature in any of a variety of industrial and scientific applications. This instrument is expected to be especially well-suited to measurement of ambient or near-ambient temperature and, even more specifically, for measuring the surface temperature of a natural body of water. Although this radiometer would utilize the long-wavelength infrared (LWIR) portion of the spectrum (wavelengths of 8 to 12 m), its basic principle of operation could also be applied to other spectral bands (corresponding to other temperature ranges) in which the atmosphere is transparent and in which design requirements for sensitivity and temperature-measurement accuracy could be satisfied.

  15. String spectra near some null cosmological singularities

    SciTech Connect

    Madhu, Kallingalthodi; Narayan, K.

    2009-06-15

    We construct cosmological spacetimes with null Kasner-like singularities as purely gravitational solutions with no other background fields turned on. These can be recast as anisotropic plane-wave spacetimes by coordinate transformations. We analyze string quantization to find the spectrum of string modes in these backgrounds. The classical string modes can be solved for exactly in these time-dependent backgrounds, which enables a detailed study of the near-singularity string spectrum, (time-dependent) oscillator masses, and wave functions. We find that for low-lying string modes (finite oscillation number), the classical near-singularity string mode functions are nondivergent for various families of singularities. Furthermore, for any infinitesimal regularization of the vicinity of the singularity, we find a tower of string modes of ultrahigh oscillation number which propagate essentially freely in the background. The resulting picture suggests that string interactions are non-negligible near the singularity.

  16. Exoplanet detection using a nulling interferometer.

    PubMed

    Cagigal, M; Canales, V

    2001-07-01

    The detection of extra solar planets is a topic of growing interest, which stretches current technology and knowledge to their limits. Indirect measurement confirms the existence of a considerable number. However, direct imaging is the only way to obtain information about the nature of these planets and to detect Earth-like planets, which could support life. The main problem for direct imaging is that planets are associated with a much brighter source of light. Here, we propose the use of the nulling interferometer along with a photon counting technique called Dark Speckle. Using a simple model the behavior of the technique is predicted. The signal-to-noise ratio estimated confirms that it is a promising way to detect faint objects. PMID:19421271

  17. Technology Advancement of the Visible Nulling Coronagraph

    NASA Technical Reports Server (NTRS)

    Lyon, Richard G.; Clampin, Mark; Petrone, Peter; Thompson, Patrick; Bolcar, Matt; Madison, Timothy; Woodruff, Robert; Noecker, Charley; Kendrick, Steve

    2010-01-01

    The critical high contrast imaging technology for the Extrasolar Planetary Imaging Coronagraph (EPIC) mission concept is the visible nulling coronagraph (VNC). EPIC would be capable of imaging jovian planets, dust/debris disks, and potentially super-Earths and contribute to answering how bright the debris disks are for candidate stars. The contrast requirement for EPIC is 10(exp 9) contrast at 125 milli-arseconds inner working angle. To advance the VNC technology NASA/Goddard Space Flight Center, in collaboration with Lockheed-Martin, previously developed a vacuum VNC testbed, and achieved narrowband and broadband suppression of the core of the Airy disk. Recently our group was awarded a NASA Technology Development for Exoplanet Missions to achieve two milestones: (i) 10(exp 8) contrast in narrowband light, and, (ii) 10(ecp 9) contrast in broader band light; one milestone per year, and both at 2 Lambda/D inner working angle. These will be achieved with our 2nd generation testbed known as the visible nulling testbed (VNT). It contains a MEMS based hex-packed segmented deformable mirror known as the multiple mirror array (MMA) and coherent fiber bundle, i.e. a spatial filter array (SFA). The MMA is in one interferometric arm and works to set the wavefront differences between the arms to zero. Each of the MMA segments is optically mapped to a single mode fiber of the SFA, and the SFA passively cleans the sub-aperture wavefront error leaving only piston, tip and tilt error to be controlled. The piston degree of freedom on each segment is used to correct the wavefront errors, while the tip/tilt is used to simultaneously correct the amplitude errors. Thus the VNT controls both amplitude and wavefront errors with a single MMA in closed-loop in a vacuum tank at approx.20 Hz. Herein we will discuss our ongoing progress with the VNT.

  18. Proof of the averaged null energy condition in a classical curved spacetime using a null-projected quantum inequality

    NASA Astrophysics Data System (ADS)

    Kontou, Eleni-Alexandra; Olum, Ken D.

    2015-12-01

    Quantum inequalities are constraints on how negative the weighted average of the renormalized stress-energy tensor of a quantum field can be. A null-projected quantum inequality can be used to prove the averaged null energy condition, which would then rule out exotic phenomena such as wormholes and time machines. In this work we derive such an inequality for a massless minimally coupled scalar field, working to first order of the Riemann tensor and its derivatives. We then use this inequality to prove the averaged null energy condition on achronal geodesics in a curved background that obeys the null convergence condition.

  19. Telomere dysfunction promotes metastasis in a Terc null mouse model of head and neck cancer

    PubMed Central

    Bojovic, Bojana; Crowe, David L.

    2011-01-01

    Squamous cell carcinoma arises from highly proliferative basal layer epithelial cells which normally divide for a short time before detaching from the basement membrane and undergoing terminal differentiation. Basal layer cells in stratified epithelia express the reverse transcriptase known as telomerase. Most human cells do not express telomerase and therefore are subject to loss of telomeric DNA with age due to the inability of lagging strand synthesis to completely replicate chromosomal ends. Late generation telomerase deficient mice exhibit signs of premature aging including reduced function of proliferating cellular compartments. We examined development of squamous cell carcinoma in a telomerase deficient murine background with long and short telomeres. G1 Terc−/− mice (long telomeres) had fewer lymph node metastases which correlated with increased numbers of apoptotic cells in these tumors compared to wild type mice. However, G5 Terc−/− mice with short telomeres had increased metastatic tumor burden similar to wild type mice. This increased metastasis correlated with genomic instability and aneuploidy in tumor cells from G5 Terc−/− mice. A number of similarities with human SCC were noted in the mouse model, and dramatic differences in global gene expression profiles were demonstrated between primary and metastatic tumors. We concluded that telomere shortening promotes metastatic tumor development in a Terc null mouse model of head and neck cancer. PMID:21593138

  20. Postexercise glucose uptake and glycogen synthesis in skeletal muscle from GLUT4-deficient mice.

    PubMed

    Ryder, J W; Kawano, Y; Galuska, D; Fahlman, R; Wallberg-Henriksson, H; Charron, M J; Zierath, J R

    1999-12-01

    To determine the role of GLUT4 on postexercise glucose transport and glycogen resynthesis in skeletal muscle, GLUT4-deficient and wild-type mice were studied after a 3 h swim exercise. In wild-type mice, insulin and swimming each increased 2-deoxyglucose uptake by twofold in extensor digitorum longus muscle. In contrast, insulin did not increase 2-deoxyglucose glucose uptake in muscle from GLUT4-null mice. Swimming increased glucose transport twofold in muscle from fed GLUT4-null mice, with no effect noted in fasted GLUT4-null mice. This exercise-associated 2-deoxyglucose glucose uptake was not accompanied by increased cell surface GLUT1 content. Glucose transport in GLUT4-null muscle was increased 1.6-fold over basal levels after electrical stimulation. Contraction-induced glucose transport activity was fourfold greater in wild-type vs. GLUT4-null muscle. Glycogen content in gastrocnemius muscle was similar between wild-type and GLUT4-null mice and was reduced approximately 50% after exercise. After 5 h carbohydrate refeeding, muscle glycogen content was fully restored in wild-type, with no change in GLUT4-null mice. After 24 h carbohydrate refeeding, muscle glycogen in GLUT4-null mice was restored to fed levels. In conclusion, GLUT4 is the major transporter responsible for exercise-induced glucose transport. Also, postexercise glycogen resynthesis in muscle was greatly delayed; unlike wild-type mice, glycogen supercompensation was not found. GLUT4 it is not essential for glycogen repletion since muscle glycogen levels in previously exercised GLUT4-null mice were totally restored after 24 h carbohydrate refeeding.-Ryder, J. W., Kawano, Y., Galuska, D., Fahlman, R., Wallberg-Henriksson, H., Charron, M. J., Zierath, J. R. Postexercise glucose uptake and glycogen synthesis in skeletal muscle from GLUT4-deficient mice. PMID:10593872

  1. Tightness of stability bounds by null space property

    NASA Astrophysics Data System (ADS)

    Chen, Xuemei; Wang, Rongrong

    2015-08-01

    The null space property (NSP) and the restricted isometry property (RIP) are two properties which have received considerable attention in the compressed sensing literature. It is known that the null space property guarantees a less than ideal stability result. In this paper, we show that this bound is actually tight by specific construction, which implies a fundamental difference between NSP and RIP.

  2. Visual and Plastic Arts in Teaching Literacy: Null Curricula?

    ERIC Educational Resources Information Center

    Wakeland, Robin Gay

    2010-01-01

    Visual and plastic arts in contemporary literacy instruction equal null curricula. Studies show that painting and sculpture facilitate teaching reading and writing (literacy), yet such pedagogy has not been formally adopted into USA curriculum. An example of null curriculum can be found in late 19th - early 20th century education the USA…

  3. Survey of Coronal Null Points with SDO/AIA & WSO

    NASA Astrophysics Data System (ADS)

    Freed, Michael; McKenzie, D. E.; Longcope, D.

    2013-07-01

    Magnetic fields in the corona can be approximated by using PFSS (Potential Field Source Surface) model in conjunction with magnetogram measurements of the photosphere. This approach is incorporated here to find locations of magnetic null points in the solar corona. Observations from WSO (Wilcox Solar Observatory) provide the necessary harmonic coefficients for a PFSS model. We located all magnetic null points in the PFSS model going back to Carrington Rotation 2098. The time and location where they cross the West limb is compared to high resolution observations made by SDO/AIA. Variations in predicted and observed null point locations, and estimates of the duration of each null, will be examined. This work will provide a catalog of coronal nulls observed by SDO that can be examined further for interesting dynamical behavior or variations in neighboring plasma.

  4. The Visible Nulling Coronagraph--Architecture Definition and Technology Development

    NASA Technical Reports Server (NTRS)

    Shao, Michael; Levine, B. Martin; Wallace, J. Kent; Liu, Duncan T.; Schmidtlin, Edouard; Serabyn, Eugene; Mennesson, Bertrand; Green, Joseph J.; Aguayo, Francisco; Fregoso, S. Felipe; Lane, Benjamin F.; Samuele, Rocco; Tuttle, Carl

    2005-01-01

    This paper describes the advantages of visible direct detection and spectroscopy of Earth-like extrasolar planets using a nulling coronagraph instrument behind a moderately sized single aperture space telescope. Our concept synthesizes a nulling interferometer by shearing the telescope pupil, with the resultant producing a deep null. We describe nulling configurations that also include methods to mitigate stellar leakage, such as spatial filtering by a coherent array of single mode fibers, and post-starlight suppression wavefront sensing and control. With diffraction limited telescope optics and similar quality components in the optical train (lambda/20), suppression of the starlight to 1e-10 is readily achievable. We describe key features of the architecture and analysis, present latest results of laboratory measurements demonstrating achievable null depth and component development, and discuss future key technical milestones.

  5. Null hypersurfaces in generalized Robertson-Walker spacetimes

    NASA Astrophysics Data System (ADS)

    Navarro, Matias; Palmas, Oscar; Solis, Didier A.

    2016-08-01

    We study the geometry of null hypersurfaces M in generalized Robertson-Walker spacetimes. First we characterize such null hypersurfaces as graphs of generalized eikonal functions over the fiber and use this characterization to show that such hypersurfaces are parallel if and only if their fibers are also parallel. We further use this technique to construct several examples of null hypersurfaces in both de Sitter and anti de Sitter spaces. Then we characterize all the totally umbilical null hypersurfaces M in a Lorentzian space form (viewed as a quadric in a semi-Euclidean ambient space) as intersections of the space form with a hyperplane. Finally we study the totally umbilical spacelike hypersurfaces of null hypersurfaces in space forms and characterize them as planar sections of M.

  6. The first mecp2-null zebrafish model shows altered motor behaviors

    PubMed Central

    Pietri, Thomas; Roman, Angel-Carlos; Guyon, Nicolas; Romano, Sebastián A.; Washbourne, Philip; Moens, Cecilia B.; de Polavieja, Gonzalo G.; Sumbre, Germán

    2013-01-01

    Rett syndrome (RTT) is an X-linked neurodevelopmental disorder and one of the most common causes of mental retardation in affected girls. Other symptoms include a rapid regression of motor and cognitive skills after an apparently early normal development. Sporadic mutations in the transcription factor MECP2 has been shown to be present in more than 90% of the patients and several models of MeCP2-deficient mice have been created to understand the role of this gene. These models have pointed toward alterations in the maintenance of the central nervous system rather than its development, in line with the late onset of the disease in humans. However, the exact functions of MeCP2 remain difficult to delineate and the animal models have yielded contradictory results. Here, we present the first mecp2-null allele mutation zebrafish model. Surprisingly and in contrast to MeCP2-null mouse models, mecp2-null zebrafish are viable and fertile. They present nonetheless clear behavioral alterations during their early development, including spontaneous and sensory-evoked motor anomalies, as well as defective thigmotaxis. PMID:23874272

  7. Role of NO Synthase in the Development of Trypanosoma cruzi–Induced Cardiomyopathy in Mice

    PubMed Central

    Durand, Jorge L.; Mukherjee, Shankar; Commodari, Fernando; De Souza, Andrea P.; Zhao, Dazhi; Machado, Fabiana S.; Tanowitz, Herbert B.; Jelicks, Linda A.

    2009-01-01

    Trypanosoma cruzi infection results in an increase in myocardial NO and intense inflammation. NO modulates the T. cruzi–induced myocardial inflammatory reaction. NO synthase (NOS)1-, NOS2-, and NOS3-null mice were infected with T. cruzi (Brazil strain). Infected NOS1-null mice had increased parasitemia, mortality, and left ventricular inner diameter (LVID). Chronically infected NOS1- and NOS2-null and wild-type mice (WT) exhibited increased right ventricular internal diameter (RVID), although the fold increase in the NOS2-null mice was smaller. Infected NOS3-null mice exhibited a significant reduction both in LVID and RVID. Reverse transcriptase-polymerase chain reaction showed expression of NOS2 and NOS3 in hearts of infected NOS1-null and WT mice, whereas infected NOS2-null hearts showed little change in expression of other NOS isoforms. Infected NOS3-null hearts showed an increase only in NOS1 expression. These results may indicate different roles for NOS isoforms in T. cruzi–induced cardiomyopathy. PMID:19407124

  8. Functional consequences of stably expressing a mutant calsequestrin (CASQ2D307H) in the CASQ2 null background

    PubMed Central

    Kalyanasundaram, Anuradha; Viatchenko-Karpinski, Serge; Belevych, Andriy E.; Lacombe, Veronique A.; Hwang, Hyun Seok; Knollmann, Björn C.; Gyorke, Sandor

    2012-01-01

    The role of calsequestrin (CASQ2) in cardiac sarcoplasmic reticulum (SR) calcium (Ca2+) transport has gained significant attention since point mutations in CASQ2 were reported to cause ventricular arrhythmia. In the present study, we have critically evaluated the functional consequences of expressing the CASQ2D307H mutant protein in the CASQ2 null mouse. We recently reported that the mutant CASQ2D307H protein can be stably expressed in CASQ2 null hearts, and it targets appropriately to the junctional SR (Kalyanasundaram A, Bal NC, Franzini-Armstrong C, Knollmann BC, Periasamy M. J Biol Chem 285: 3076–3083, 2010). In this study, we found that introduction of CASQ2D307H protein in the CASQ2 null background partially restored triadin 1 levels, which were decreased in the CASQ2 null mice. Despite twofold expression (relative to wild-type CASQ2), the mutant protein failed to increase SR Ca2+ load. We also found that the Ca2+ transient decays slower in the CASQ2 null and CASQ2D307H cells. CASQ2D307H myocytes, when rhythmically paced and challenged with isoproterenol, exhibit spontaneous Ca2+ waves similar to CASQ2 null myocytes; however, the stability of Ca2+ cycling was increased in the CASQ2D307H myocytes. In the presence of isoproterenol, Ca2+-transient amplitude in CASQ2D307H myocytes was significantly decreased, possibly indicating an inherent defect in Ca2+ buffering capacity and release from the mutant CASQ2 at high Ca2+ concentrations. We also observed polymorphic ventricular tachycardia in the CASQ2D307H mice, although lesser than in the CASQ2 null mice. These data suggest that CASQ2D307H point mutation may affect Ca2+ buffering capacity and Ca2+ release. We propose that poor interaction between CASQ2D307H and triadin 1 could affect ryanodine receptor 2 stability, thereby increasing susceptibility to delayed afterdepolarizations and triggered arrhythmic activity. PMID:21984545

  9. Wormholes minimally violating the null energy condition

    SciTech Connect

    Bouhmadi-López, Mariam; Lobo, Francisco S N; Martín-Moruno, Prado E-mail: fslobo@fc.ul.pt

    2014-11-01

    We consider novel wormhole solutions supported by a matter content that minimally violates the null energy condition. More specifically, we consider an equation of state in which the sum of the energy density and radial pressure is proportional to a constant with a value smaller than that of the inverse area characterising the system, i.e., the area of the wormhole mouth. This approach is motivated by a recently proposed cosmological event, denoted {sup t}he little sibling of the big rip{sup ,} where the Hubble rate and the scale factor blow up but the cosmic derivative of the Hubble rate does not [1]. By using the cut-and-paste approach, we match interior spherically symmetric wormhole solutions to an exterior Schwarzschild geometry, and analyse the stability of the thin-shell to linearized spherically symmetric perturbations around static solutions, by choosing suitable properties for the exotic material residing on the junction interface radius. Furthermore, we also consider an inhomogeneous generalization of the equation of state considered above and analyse the respective stability regions. In particular, we obtain a specific wormhole solution with an asymptotic behaviour corresponding to a global monopole.

  10. The curious case of null warped space

    NASA Astrophysics Data System (ADS)

    Anninos, Dionysios; Compère, Geoffrey; de Buyl, Sophie; Detournay, Stéphane; Guica, Monica

    2010-11-01

    We initiate a comprehensive study of a set of solutions of topologically massive gravity known as null warped anti-de Sitter spacetimes. These are pp-wave extensions of three-dimensional anti-de Sitter space. We first perform a careful analysis of the linearized stability of black holes in these spacetimes. We find two qualitatively different types of solutions to the linearized equations of motion: the first set has an exponential time dependence, the second — a polynomial time dependence. The solutions polynomial in time induce severe pathologies and moreover survive at the non-linear level. In order to make sense of these geometries, it is thus crucial to impose appropriate boundary conditions. We argue that there exists a consistent set of boundary conditions that allows us to reject the above pathological modes from the physical spectrum. The asymptotic symmetry group associated to these boundary conditions consists of a centrally-extended Virasoro algebra. Using this central charge we can account for the entropy of the black holes via Cardy's formula. Finally, we note that the black hole spectrum is chiral and prove a Birkoff theorem showing that there are no other stationary axisymmetric black holes with the specified asymptotics. We extend most of the analysis to a larger family of pp-wave black holes which are related to Schrödinger spacetimes with critical exponent z.

  11. A Null Model for Pearson Coexpression Networks

    PubMed Central

    Gobbi, Andrea; Jurman, Giuseppe

    2015-01-01

    Gene coexpression networks inferred by correlation from high-throughput profiling such as microarray data represent simple but effective structures for discovering and interpreting linear gene relationships. In recent years, several approaches have been proposed to tackle the problem of deciding when the resulting correlation values are statistically significant. This is most crucial when the number of samples is small, yielding a non-negligible chance that even high correlation values are due to random effects. Here we introduce a novel hard thresholding solution based on the assumption that a coexpression network inferred by randomly generated data is expected to be empty. The threshold is theoretically derived by means of an analytic approach and, as a deterministic independent null model, it depends only on the dimensions of the starting data matrix, with assumptions on the skewness of the data distribution compatible with the structure of gene expression levels data. We show, on synthetic and array datasets, that the proposed threshold is effective in eliminating all false positive links, with an offsetting cost in terms of false negative detected edges. PMID:26030917

  12. 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. PMID:20739667

  13. Reduction in Dietary Omega-6 Polyunsaturated Fatty Acids: Eicosapentaenoic Acid plus Docosahexaenoic Acid Ratio Minimizes Atherosclerotic Lesion Formation and Inflammatory Response in the LDL Receptor Null Mouse

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dietary very long chain omega-3 polyunsaturated fatty acids (PUFA) have been associated with reduced CVD risk. LDL receptor null mice (LDLr-/-) were used to assess different dietary ratios of omega-6 PUFA to eicosapentaenoic acid plus docosahexaenoic acid (omega-6:EPA+DHA) on atherogenesis and infl...

  14. Effect of a null mutation of the oviduct-specific glycoprotein gene on mouse fertilization.

    PubMed Central

    Araki, Yoshihiko; Nohara, Makoto; Yoshida-Komiya, Hiromi; Kuramochi, Takashi; Ito, Mamoru; Hoshi, Hiroyoshi; Shinkai, Yoichi; Sendai, Yutaka

    2003-01-01

    The mammalian fertilization process takes place in a complex microenvironment within the female genital tract. A member of the chitinase protein family, oviduct-specific glycoprotein (OGP), has been identified in oviductal fluid from various mammalian species, including humans. Although OGP is widely believed to be involved in the process of mammalian fertilization, including spermatozoon function and gamete interactions, based on experimental results obtained in vitro, its physiological significance remains controversial. The present study established OGP gene-null ( ogp (-/-)) mice, and primarily characterized their reproductive properties to study the physiological function(s) of OGP. Results obtained from studies using an in vivo or in vitro system showed that the fertility of ogp (-/-) females was within normal limits. These results indicate that OGP is not essential for the process of in vivo fertilization, at least in mice. PMID:12814341

  15. Null fields in the outer Jovian magnetosphere: ULYSSES observations

    NASA Astrophysics Data System (ADS)

    Haynes, P. L.; Balogh, A.; Dougherty, M. K.; Southwood, D. J.; Fazakerley, A.

    1994-03-01

    This paper reports on a magnetic field phenomenon, hereafter referred to as null fields, which were discovered during the inbound pass of the recent flyby of Jupiter by the Ulysses spacecraft. These null fields which were observed in the outer dayside magnetosphere are characterised by brief but sharp decreases of the field magnitude to values less than 1 nT. The nulls are distinguished from the current sheet signatures characteristic of the middle magnetosphere by the fact that the field does not reverse across the event. A field configuration is suggested that accounts for the observed features of the events.

  16. Molecular basis for the CAT-2 null phenotype in maize

    SciTech Connect

    Bethards, L.A.; Scandalios, J.G.

    1988-01-01

    Previous reports have described several maize lines whose developmental patterns of catalase gene expression vary from the typical maize line, W64A. Among these variants are the lines A16 and A338, both found to be null for the CAT-2 protein. Identification of a third CAT-2 null line, designated A340, is described. RNA blots and S1 nuclease protection analysis, using (/sup 32/P)-labeled dCTP, indicate that all three CAT-2 null lines produce a similarly shortened Cat2 transcript. The molecular basis for this aberrant Cat2 transcript is discussed.

  17. Lethal Keratitis, Ichthyosis, and Deafness Syndrome Due to the A88V Connexin 26 Mutation.

    PubMed

    Esmer, Carmen; Salas-Alanis, Julio C; Fajardo-Ramirez, Oscar R; Ramírez, Brenda; Hua, Rong; Choate, Keith

    2016-01-01

    Keratitis-ichthyosis-deafness syndrome is a well-characterized disease that has been related to mutations in the GJB6 gene. Clinical features such as erythrokeratoderma, palmoplantar keratoderma, alopecia, and progressive vascularizing keratitis, among others, are well known in this entity. In this report we describe a newborn female patient diagnosed with keratitis-ichthyosis-deafness syndrome with a lethal outcome due to sepsis. The patient harbored the mutation A88V that has been previously reported in lethal cases. PMID:27409001

  18. Mechanism for modulation of gating of connexin26-containing channels by taurine

    PubMed Central

    Kieken, Fabien; Tao, Liang; Sorgen, Paul L.; Harris, Andrew L.

    2011-01-01

    The mechanisms of action of endogenous modulatory ligands of connexin channels are largely unknown. Previous work showed that protonated aminosulfonates (AS), notably taurine, directly and reversibly inhibit homomeric and heteromeric channels that contain Cx26, a widely distributed connexin, but not homomeric Cx32 channels. The present study investigated the molecular mechanisms of connexin channel modulation by taurine, using hemichannels and junctional channels composed of Cx26 (homomeric) and Cx26/Cx32 (heteromeric). The addition of a 28–amino acid “tag” to the carboxyl-terminal domain (CT) of Cx26 (Cx26T) eliminated taurine sensitivity of homomeric and heteromeric hemichannels in cells and liposomes. Cleavage of all but four residues of the tag (Cx26Tc) resulted in taurine-induced pore narrowing in homomeric hemichannels, and restored taurine inhibition of heteromeric hemichannels (Cx26Tc/Cx32). Taurine actions on junctional channels were fully consistent with those on hemichannels. Taurine-induced inhibition of Cx26/Cx32T and nontagged Cx26 junctional channels was blocked by extracellular HEPES, a blocker of the taurine transporter, confirming that the taurine-sensitive site of Cx26 is cytoplasmic. Nuclear magnetic resonance of peptides corresponding to Cx26 cytoplasmic domains showed that taurine binds to the cytoplasmic loop (CL) and not the CT, and that the CT and CL directly interact. ELISA showed that taurine disrupts a pH-dependent interaction between the CT and the CT-proximal half of the CL. These studies reveal that AS disrupt a pH-driven cytoplasmic interdomain interaction in Cx26-containing channels, causing closure, and that the Cx26CT has a modulatory role in Cx26 function. PMID:21844220

  19. Intercellular Redistribution of cAMP Underlies Selective Suppression of Cancer Cell Growth by Connexin26

    PubMed Central

    Polusani, Srikanth R.; Mathis, Sandra A.; Zucker, Shoshanna N.; Nicholson, Bruce J.

    2013-01-01

    Connexins (Cx), which constitute gap junction intercellular channels in vertebrates, have been shown to suppress transformed cell growth and tumorigenesis, but the mechanism(s) still remain largely speculative. Here, we define the molecular basis by which Cx26, but less frequently Cx43 or Cx32, selectively confer growth suppression on cancer cells. Functional intercellular coupling is shown to be required, producing partial blocks of the cell cycle due to prolonged activation of several mitogenic kinases. PKA is both necessary and sufficient for the Cx26 induced growth inhibition in low serum and the absence of anchorage. Activation of PKA was not associated with elevated cAMP levels, but appeared to result from a redistribution of cAMP throughout the cell population, eliminating the cell cycle oscillations in cAMP required for efficient cell cycle progression. Cx43 and Cx32 fail to mediate this redistribution as, unlike Cx26, these channels are closed during the G2/M phase of the cell cycle when cAMP levels peak. Comparisons of tumor cell lines indicate that this is a general pattern, with growth suppression by connexins occurring whenever cAMP oscillates with the cell cycle, and the gap junction remain open throughout the cell cycle. Thus, gap junctional coupling, in the absence of any external signals, provides a general means to limit the mitotic rate of cell populations. PMID:24312655

  20. Intercellular redistribution of cAMP underlies selective suppression of cancer cell growth by connexin26.

    PubMed

    Chandrasekhar, Anjana; Kalmykov, Edward A; Polusani, Srikanth R; Mathis, Sandra A; Zucker, Shoshanna N; Nicholson, Bruce J

    2013-01-01

    Connexins (Cx), which constitute gap junction intercellular channels in vertebrates, have been shown to suppress transformed cell growth and tumorigenesis, but the mechanism(s) still remain largely speculative. Here, we define the molecular basis by which Cx26, but less frequently Cx43 or Cx32, selectively confer growth suppression on cancer cells. Functional intercellular coupling is shown to be required, producing partial blocks of the cell cycle due to prolonged activation of several mitogenic kinases. PKA is both necessary and sufficient for the Cx26 induced growth inhibition in low serum and the absence of anchorage. Activation of PKA was not associated with elevated cAMP levels, but appeared to result from a redistribution of cAMP throughout the cell population, eliminating the cell cycle oscillations in cAMP required for efficient cell cycle progression. Cx43 and Cx32 fail to mediate this redistribution as, unlike Cx26, these channels are closed during the G2/M phase of the cell cycle when cAMP levels peak. Comparisons of tumor cell lines indicate that this is a general pattern, with growth suppression by connexins occurring whenever cAMP oscillates with the cell cycle, and the gap junction remain open throughout the cell cycle. Thus, gap junctional coupling, in the absence of any external signals, provides a general means to limit the mitotic rate of cell populations. PMID:24312655

  1. Impaired olfaction in mice lacking aquaporin-4 water channels

    PubMed Central

    Lu, Daniel C.; Zhang, Hua; Zador, Zsolt; Verkman, A. S.

    2008-01-01

    Aquaporin-4 (AQP4) is a water-selective transport protein expressed in glial cells throughout the central nervous system. AQP4 deletion in mice produces alterations in several neuroexcitation phenomena, including hearing, vision, epilepsy, and cortical spreading depression. Here, we report defective olfaction and electroolfactogram responses in AQP4-null mice. Immunofluorescence indicated strong AQP4 expression in supportive cells of the nasal olfactory epithelium. The olfactory epithelium in AQP4-null mice had identical appearance, but did not express AQP4, and had ∼12-fold reduced osmotic water permeability. Behavioral analysis showed greatly impaired olfaction in AQP4-null mice, with latency times of 17 ± 0.7 vs. 55 ± 5 s in wild-type vs. AQP4-null mice in a buried food pellet test, which was confirmed using an olfactory maze test. Electroolfactogram voltage responses to multiple odorants were reduced in AQP4-null mice, with maximal responses to triethylamine of 0.80 ± 0.07 vs. 0.28 ± 0.03 mV. Similar olfaction and electroolfactogram defects were found in outbred (CD1) and inbred (C57/bl6) mouse genetic backgrounds. Our results establish AQP4 as a novel determinant of olfaction, the deficiency of which probably impairs extracellular space K+ buffering in the olfactory epithelium.—Lu, D. C., Zhang, H., Zador, Z., Verkman, A. S. Impaired olfaction in mice lacking aquaporin-4 water channels. PMID:18511552

  2. A boundary term for the gravitational action with null boundaries

    NASA Astrophysics Data System (ADS)

    Parattu, Krishnamohan; Chakraborty, Sumanta; Majhi, Bibhas Ranjan; Padmanabhan, T.

    2016-07-01

    Constructing a well-posed variational principle is a non-trivial issue in general relativity. For spacelike and timelike boundaries, one knows that the addition of the Gibbons-Hawking-York (GHY) counter-term will make the variational principle well-defined. This result, however, does not directly generalize to null boundaries on which the 3-metric becomes degenerate. In this work, we address the following question: What is the counter-term that may be added on a null boundary to make the variational principle well-defined? We propose the boundary integral of 2 √{-g} ( Θ +κ ) as an appropriate counter-term for a null boundary. We also conduct a preliminary analysis of the variations of the metric on the null boundary and conclude that isolating the degrees of freedom that may be fixed for a well-posed variational principle requires a deeper investigation.

  3. A null-steering viewpoint of interferometric SAR

    SciTech Connect

    BICKEL,DOUGLAS L.

    2000-05-02

    Interferometric synthetic aperture radar (IFSAR) extends the two-dimensional imaging capability of traditional synthetic aperture radar to three-dimensions by using an aperture in the elevation plane to estimate the 3-D structure of the target. The operation of this additional aperture can be viewed from a null-steering point of view, rather than the traditional phase determination point of view. Knowing that IFSAR can be viewed from the null-steering perspective allows one to take advantage of the mathematical foundation developed for null-steering arrays. In addition, in some problems of interest in IFSAR the null-steering perspective provides better intuition and suggests alternative solutions. One example is the problem of estimating building height where layover is present.

  4. Radiant Temperature Nulling Radiometer and Polarization Enhanced Thermal Radiometer

    NASA Technical Reports Server (NTRS)

    Bailey, John

    2002-01-01

    The two radiometers profiled in this viegraph presentation, the Radiant Temperature Nulling Radiometer and the Polarization Enhanced Thermal Radiometer, were developed for the calibration of remote sensing equipment. This presentation profiles the theory and components of each type of radiometer.

  5. Susceptibility of Nrf2-Null Mice to Steatohepatitis and Cirrhosis upon Consumption of a High-Fat Diet Is Associated with Oxidative Stress, Perturbation of the Unfolded Protein Response, and Disturbance in the Expression of Metabolic Enzymes but Not with Insulin Resistance

    PubMed Central

    Meakin, Paul J.; Chowdhry, Sudhir; Sharma, Ritu S.; Ashford, Fiona B.; Walsh, Shaun V.; McCrimmon, Rory J.; Dinkova-Kostova, Albena T.; Dillon, John F.

    2014-01-01

    Mice lacking the transcription factor NF-E2 p45-related factor 2 (Nrf2) develop more severe nonalcoholic steatohepatitis (NASH), with cirrhosis, than wild-type (Nrf2+/+) mice when fed a high-fat (HF) diet for 24 weeks. Although NASH is usually associated with insulin resistance, HF-fed Nrf2−/− mice exhibited better insulin sensitivity than HF-fed Nrf2+/+ mice. In livers of HF-fed mice, loss of Nrf2 resulted in greater induction of lipogenic genes, lower expression of β-oxidation genes, greater reduction in AMP-activated protein kinase (AMPK) levels, and diminished acetyl coenzyme A (CoA) carboxylase phosphorylation than in the wild-type livers, which is consistent with greater fatty acid (FA) synthesis in Nrf2−/− livers. Moreover, primary Nrf2−/− hepatocytes displayed lower glucose and FA oxidation than Nrf2+/+ hepatocytes, with FA oxidation partially rescued by treatment with AMPK activators. The unfolded protein response (UPR) was perturbed in control regular-chow (RC)-fed Nrf2−/− mouse livers, and this was associated with constitutive activation of NF-κB and JNK, along with upregulation of inflammatory genes. The HF diet elicited an antioxidant response in Nrf2+/+ livers, and as this was compromised in Nrf2−/− livers, they suffered oxidative stress. Therefore, Nrf2 protects against NASH by suppressing lipogenesis, supporting mitochondrial function, increasing the threshold for the UPR and inflammation, and enabling adaptation to HF-diet-induced oxidative stress. PMID:24958099

  6. Another Nulling Hall-Effect Current-Measuring Circuit

    NASA Technical Reports Server (NTRS)

    Thibodeau, Phillip E.; Sullender, Craig C.

    1993-01-01

    Lightweight, low-power circuit provides noncontact measurement of alternating or direct current of many ampheres in main conductor. Advantages of circuit over other nulling Hall-effect current-measuring circuits is stability and accuracy increased by putting both analog-to-digital and digital-to-analog converters in nulling feedback loop. Converters and rest of circuit designed for operation at sampling rate of 100 kHz, but rate changed to alter time or frequency response of circuit.

  7. Antimultipath communication by injecting tone into null in signal spectrum

    NASA Technical Reports Server (NTRS)

    Davarian, Faramaz (Inventor)

    1987-01-01

    A transmitter for digital radio communication creates a null by balanced encoding of data modulated on an RF carrier, and inserts a calibration tone within the null. This is accomplished by having the calibration tone coincide in phase and frequency with the transmitted radio frequency output, for coherent demodulation of data at the receiver where the tone calibration signal is extracted and used for multipath fading compensation.

  8. Experimental Progress and Results of a Visible Nulling Coronagraph

    NASA Technical Reports Server (NTRS)

    Samuele, Rocco; Wallace, J. Kent; Schmidtlin, Edouard; Shao, Mike; Levine, B. Martin; Fregoso, Santos

    2007-01-01

    The crux of visible exoplanet detection is overcoming significant star-planet contrast ratios on the order of 10(exp -7) to 10(exp -10)-at very small angular separations. We are developing an interferometric nulling coronagraph designed to achieve a 10(exp -6) contrast ratio at a working science bandpass of 20% visible light. Achieving large, broadband suppression requires a pseudo-achromatic phase flip, while maintaining a strict error budget. Recent results from our nulling interferometer testbed yield contrast ratios at the 1.05x10(exp -6) level, with a 15% visible bandpass. This result is at 65% of our final bandpass requirement, although limitations of our current configuration make major hardware changes essential to broadening the bandpass. We make the argument that broadening the bandpass should not necessarily adversely affect the null depth until beyond the 20% visible light level. Using the same setup we are able to reach monochromatic null depths of 1.11x10(exp -7) (?= 638 nm)averaged over three seconds. This paper will describe our experimental approach for achieving deep broadband nulls, as well as error considerations and limitations, and the most recent results for our nulling coronagraph testbed.

  9. Measurement Via Optical Near-Nulling and Subaperture Stitching

    NASA Technical Reports Server (NTRS)

    Forbes, Greg; De Vries, Gary; Murphy, Paul; Brophy, Chris

    2012-01-01

    A subaperture stitching interferometer system provides near-nulling of a subaperture wavefront reflected from an object of interest over a portion of a surface of the object. A variable optical element located in the radiation path adjustably provides near-nulling to facilitate stitching of subaperture interferograms, creating an interferogram representative of the entire surface of interest. This enables testing of aspheric surfaces without null optics customized for each surface prescription. The surface shapes of objects such as lenses and other precision components are often measured with interferometry. However, interferometers have a limited capture range, and thus the test wavefront cannot be too different from the reference or the interference cannot be analyzed. Furthermore, the performance of the interferometer is usually best when the test and reference wavefronts are nearly identical (referred to as a null condition). Thus, it is necessary when performing such measurements to correct for known variations in shape to ensure that unintended variations are within the capture range of the interferometer and accurately measured. This invention is a system for nearnulling within a subaperture stitching interferometer, although in principle, the concept can be employed by wavefront measuring gauges other than interferometers. The system employs a light source for providing coherent radiation of a subaperture extent. An object of interest is placed to modify the radiation (e.g., to reflect or pass the radiation), and a variable optical element is located to interact with, and nearly null, the affected radiation. A detector or imaging device is situated to obtain interference patterns in the modified radiation. Multiple subaperture interferograms are taken and are stitched, or joined, to provide an interferogram representative of the entire surface of the object of interest. The primary aspect of the invention is the use of adjustable corrective optics in the

  10. Juvenile manifestation of ultrasound communication deficits in the neuroligin-4 null mutant mouse model of autism.

    PubMed

    Ju, Anes; Hammerschmidt, Kurt; Tantra, Martesa; Krueger, Dilja; Brose, Nils; Ehrenreich, Hannelore

    2014-08-15

    Neuroligin-4 (Nlgn4) is a member of the neuroligin family of postsynaptic cell adhesion molecules. Loss-of-function mutations of NLGN4 are among the most frequent, known genetic causes of heritable autism. Adult Nlgn4 null mutant (Nlgn4(-/-)) mice are a construct valid model of human autism, with both genders displaying a remarkable autistic phenotype, including deficits in social interaction and communication as well as restricted and repetitive behaviors. In contrast to adults, autism-related abnormalities in neonatal and juvenile Nlgn4(-/-) mice have not been reported yet. The present study has been designed to systematically investigate in male and female Nlgn4(-/-) pups versus wildtype littermates (WT, Nlgn4(+/+)) developmental milestones and stimulus-induced ultrasound vocalization (USV). Neonatal development, followed daily from postnatal days (PND) 4 to 21, including physical development, neurological reflexes and neuromotor coordination, did not yield any differences between Nlgn4(-/-) and their WT littermates. USV in pups (PND8-9) in response to brief separation from their mothers revealed remarkable gender effects, and a genotype influence in females regarding latency to first call. In juveniles (PND22-23), USV monitoring upon exposure to an anesthetized female intruder mouse uncovered a clear genotype effect with reduced USV in Nlgn4(-/-) mice, and again a more prominent phenotype in females. Together, these data support an early manifestation of communication deficits in Nlgn4(-/-) mice that appear more pronounced in immature females with their overall stronger USV as compared to males. PMID:24855039

  11. lagC-null and gbf-null cells define key steps in the morphogenesis of Dictyostelium mounds.

    PubMed

    Sukumaran, S; Brown, J M; Firtel, R A; McNally, J G

    1998-08-01

    The transition to multicellularity is a key feature of the Dictyostelium life cycle, and two genes, gbf and lagC, are known to play pivotal roles in regulating this developmental switch. lagC-null and gbf-null cells fail to induce cell-type-specific genes ordinarily expressed during multicellular development. The null mutants also share a similar morphological phenotype: mutant cells repeatedly aggregate to form a loose mound, disperse, and reform a mound, rather than proceeding to form a tip. To characterize defects in morphogenesis in these mutants, we examined cell motion in the mutant mounds. In analogy with the failed transition in gene expression, we found that lagC-null and gbf-null mounds failed to make a morphogenetic transition from random to rotational motion normally observed in the parent strain. One reason for this was the inability of the mutant mounds to establish a single, dominant signaling-wave center. This defect of lagC-null or gbf-null cells could be overcome by the addition of adenosine, which alters cAMP signaling, but then even in the presence of apparently normal signaling waves, cell motility was still aberrant. This motility defect, as well as the signaling-wave defect, could be overcome in lagC-null cells by overexpression of GBF, suggesting that lagC is dispensable if GBF protein levels are high enough. This set of morphogenetic defects that we have observed helps define key steps in mound morphogenesis. These include the establishment of a dominant signaling-wave center and the capacity of cells to move directionally within the cell mass in response to guidance cues. PMID:9698452

  12. Impaired olfaction in mice lacking aquaporin-4 water channels.

    PubMed

    Lu, Daniel C; Zhang, Hua; Zador, Zsolt; Verkman, A S

    2008-09-01

    Aquaporin-4 (AQP4) is a water-selective transport protein expressed in glial cells throughout the central nervous system. AQP4 deletion in mice produces alterations in several neuroexcitation phenomena, including hearing, vision, epilepsy, and cortical spreading depression. Here, we report defective olfaction and electroolfactogram responses in AQP4-null mice. Immunofluorescence indicated strong AQP4 expression in supportive cells of the nasal olfactory epithelium. The olfactory epithelium in AQP4-null mice had identical appearance, but did not express AQP4, and had approximately 12-fold reduced osmotic water permeability. Behavioral analysis showed greatly impaired olfaction in AQP4-null mice, with latency times of 17 +/- 0.7 vs. 55 +/- 5 s in wild-type vs. AQP4-null mice in a buried food pellet test, which was confirmed using an olfactory maze test. Electroolfactogram voltage responses to multiple odorants were reduced in AQP4-null mice, with maximal responses to triethylamine of 0.80 +/- 0.07 vs. 0.28 +/- 0.03 mV. Similar olfaction and electroolfactogram defects were found in outbred (CD1) and inbred (C57/bl6) mouse genetic backgrounds. Our results establish AQP4 as a novel determinant of olfaction, the deficiency of which probably impairs extracellular space K(+) buffering in the olfactory epithelium. PMID:18511552

  13. Compensation for PKMζ in long-term potentiation and spatial long-term memory in mutant mice

    PubMed Central

    Tsokas, Panayiotis; Hsieh, Changchi; Yao, Yudong; Lesburguères, Edith; Wallace, Emma Jane Claire; Tcherepanov, Andrew; Jothianandan, Desingarao; Hartley, Benjamin Rush; Pan, Ling; Rivard, Bruno; Farese, Robert V; Sajan, Mini P; Bergold, Peter John; Hernández, Alejandro Iván; Cottrell, James E; Shouval, Harel Z; Fenton, André Antonio; Sacktor, Todd Charlton

    2016-01-01

    PKMζ is a persistently active PKC isoform proposed to maintain late-LTP and long-term memory. But late-LTP and memory are maintained without PKMζ in PKMζ-null mice. Two hypotheses can account for these findings. First, PKMζ is unimportant for LTP or memory. Second, PKMζ is essential for late-LTP and long-term memory in wild-type mice, and PKMζ-null mice recruit compensatory mechanisms. We find that whereas PKMζ persistently increases in LTP maintenance in wild-type mice, PKCι/λ, a gene-product closely related to PKMζ, persistently increases in LTP maintenance in PKMζ-null mice. Using a pharmacogenetic approach, we find PKMζ-antisense in hippocampus blocks late-LTP and spatial long-term memory in wild-type mice, but not in PKMζ-null mice without the target mRNA. Conversely, a PKCι/λ-antagonist disrupts late-LTP and spatial memory in PKMζ-null mice but not in wild-type mice. Thus, whereas PKMζ is essential for wild-type LTP and long-term memory, persistent PKCι/λ activation compensates for PKMζ loss in PKMζ-null mice. DOI: http://dx.doi.org/10.7554/eLife.14846.001 PMID:27187150

  14. Compensation for PKMζ in long-term potentiation and spatial long-term memory in mutant mice.

    PubMed

    Tsokas, Panayiotis; Hsieh, Changchi; Yao, Yudong; Lesburguères, Edith; Wallace, Emma Jane Claire; Tcherepanov, Andrew; Jothianandan, Desingarao; Hartley, Benjamin Rush; Pan, Ling; Rivard, Bruno; Farese, Robert V; Sajan, Mini P; Bergold, Peter John; Hernández, Alejandro Iván; Cottrell, James E; Shouval, Harel Z; Fenton, André Antonio; Sacktor, Todd Charlton

    2016-01-01

    PKMζ is a persistently active PKC isoform proposed to maintain late-LTP and long-term memory. But late-LTP and memory are maintained without PKMζ in PKMζ-null mice. Two hypotheses can account for these findings. First, PKMζ is unimportant for LTP or memory. Second, PKMζ is essential for late-LTP and long-term memory in wild-type mice, and PKMζ-null mice recruit compensatory mechanisms. We find that whereas PKMζ persistently increases in LTP maintenance in wild-type mice, PKCι/λ, a gene-product closely related to PKMζ, persistently increases in LTP maintenance in PKMζ-null mice. Using a pharmacogenetic approach, we find PKMζ-antisense in hippocampus blocks late-LTP and spatial long-term memory in wild-type mice, but not in PKMζ-null mice without the target mRNA. Conversely, a PKCι/λ-antagonist disrupts late-LTP and spatial memory in PKMζ-null mice but not in wild-type mice. Thus, whereas PKMζ is essential for wild-type LTP and long-term memory, persistent PKCι/λ activation compensates for PKMζ loss in PKMζ-null mice. PMID:27187150

  15. Allergic inflammatory response to short ragweed allergenic extract in HLA-DQ transgenic mice lacking CD4 gene.

    PubMed

    Chapoval, Svetlana P; Iijima, Koji; Marietta, Eric V; Smart, Michele K; Chapoval, Andrei I; Andrews, Amy G; David, Chella S

    2002-01-15

    To investigate the role of HLA-DQ molecules and/or CD4(+) T cells in the pathogenesis of allergic asthma, we generated HLA-DQ6 and HLA-DQ8 transgenic mice lacking endogenous class II (Abeta(null)) and CD4 genes and challenged them intranasally with short ragweed allergenic extract (SRW). We found that DQ6/CD4(null) mice developed a strong eosinophilic infiltration into the bronchoalveolar lavage and lung tissue, while DQ8/CD4(null) mice were normal. However, neither cytokines nor eosinophil peroxidase in the bronchoalveolar lavage of DQ6/CD4(null) mice was found. In addition, the airway reactivity to methacholine was elevated moderately in DQ6/CD4(null) mice compared with the high response in DQ/CD4(+) counterparts and was only partially augmented by CD4(+) T cell transfer. The DQ6/CD4(null) mice showed Th1/Th2-type cytokines and SRW-specific Abs in the immune sera in contrast to a direct Th2 response observed in DQ6/CD4(+) mice. The proliferative response of spleen mononuclear cells and peribronchial lymph node cells demonstrated that the response to SRW in DQ6/CD4(null) mice was mediated by HLA-DQ-restricted CD4(-)CD8(-)NK1.1(-) T cells. FACS analysis of PBMC and spleen mononuclear cells demonstrated an expansion of double-negative (DN) CD4(-)CD8(-)TCRalphabeta(+) T cells in SRW-treated DQ6/CD4(null) mice. These cells produced IL-4, IL-5, IL-13, and IFN-gamma when stimulated with immobilized anti-CD3. IL-5 ELISPOT assay revealed that DN T cells were the cellular origin of IL-5 in allergen-challenged DQ6/CD4(null) mice. Our study shows a role for HLA-DQ-restricted CD4(+) and DN T cells in the allergic response. PMID:11777987

  16. Interferometric nulling of four channels with integrated optics.

    PubMed

    Errmann, Ronny; Minardi, Stefano; Labadie, Lucas; Muthusubramanian, Balaji; Dreisow, Felix; Nolte, Stefan; Pertsch, Thomas

    2015-08-20

    Nulling interferometry has been identified as a competitive technique for the detection of extrasolar planets. In its basic form, the technique consists of combining out-of-phase a single pair of telescopes to effectively null the light of a bright star and reveal the dim glow of the companion. However, in order to mitigate the effect of the stellar leaks through the interferometer, a broad angular central null is required. The hierarchical combination of several pairs of telescopes can accomplish this task. We have manufactured and tested with monochromatic light an integrated optics component, which combines a linear array of four telescopes in the nulling mode envisaged by Angel and Woolf [Astroph. J.475, 373-379 (1997).10.1086/apj.1997.475.issue-1ASJOAB0004-637X]. By simulating in the laboratory the motion of a star in the sky, we could measure the expected angular transmission of the four-telescope nuller. Moreover, the tests have demonstrated a broad nulling scaling as the fourth power of the baseline delay. PMID:26368784

  17. Achromatic phase shifts utilizing dielectric plates for nulling interferometery

    NASA Astrophysics Data System (ADS)

    Morgan, R. M.; Burge, J. M.

    1998-12-01

    Schemes for detecting planets around other stars using interferometery have been developed which rely on a half wave phase delay to shift the central constructive fringe of an interferometer to a deep, destructive null fringe. To achieve the sensitivity and spectroscopy desired for exo-planets observations, such a null must be achromatic over a broad spectral region. One method for creating such a half wave phase delay achromatically involves the use of pairs of dielectric, plane parallel plates, analogous to the use of two types of glass in an achromatic lens. An analysis of the technique is presented with solutions using single plates to achieve null fringes to a cancellation of 10 exp -4 in the visible, near infrared, and mid infrared for null. Solutions using two matched materials show that nulls to a depth of 10 exp -6 are achievable in 2 um bands in the 7-17 um regime, or to a depth of 10 exp -5 over the entire 7-17 um band. Experimental results using a single plate of BK7 in the visible spectrum verify the technique.

  18. Do Null Subjects (mis-)Trigger Pro-drop Grammars?

    PubMed

    Frazier, Lyn

    2015-12-01

    Native speakers of English regularly hear sentences without overt subjects. Nevertheless, they maintain a [−pro] grammar that requires sentences to have an overt subject. It is proposed that listeners of English recognize that speakers reduce predictable material and thus attribute null subjects to this process, rather than changing their grammars to a [−pro] setting. Mack et al. (J Memory Lang 67(1):211-223, 2012) showed that sentences with noise covering the subject are analyzed as having null subjects more often with a first person pronoun and with a present tense--properties correlated with more predictable referents--compared to a third person pronoun and past tense. However, those results might in principle have been due to reporting null subjects for verbs that often occur with null subjects. An experiment is reported here in which comparable results are found for sentences containing nonsense verbs. Participants preferred a null subject more often for first person present tense sentences than for third person past tense sentences. The results are as expected if participants are responding to predictability, the likelihood of reduction, rather than to lexical statistics. The results are argued to be important in removing a class of mis-triggering examples from the language acquisition problem. PMID:25086703

  19. Ballooning modes localized near the null point of a divertor

    SciTech Connect

    Farmer, W. A.

    2014-04-15

    The stability of ballooning modes localized to the null point in both the standard and snowflake divertors is considered. Ideal magnetohydrodynamics is used. A series expansion of the flux function is performed in the vicinity of the null point with the lowest, non-vanishing term retained for each divertor configuration. The energy principle is used with a trial function to determine a sufficient instability threshold. It is shown that this threshold depends on the orientation of the flux surfaces with respect to the major radius with a critical angle appearing due to the convergence of the field lines away from the null point. When the angle the major radius forms with respect to the flux surfaces exceeds this critical angle, the system is stabilized. Further, the scaling of the instability threshold with the aspect ratio and the ratio of the scrape-off-layer width to the major radius is shown. It is concluded that ballooning modes are not a likely candidate for driving convection in the vicinity of the null for parameters relevant to existing machines. However, the results place a lower bound on the width of the heat flux in the private flux region. To explain convective mixing in the vicinity of the null point, new consideration should be given to an axisymmetric mixing mode [W. A. Farmer and D. D. Ryutov, Phys. Plasmas 20, 092117 (2013)] as a possible candidate to explain current experimental results.

  20. Visible Nulling Coronagraphy Testbed Development for Exoplanet Detection

    NASA Technical Reports Server (NTRS)

    Lyon, Richard G.; Clampin, Mark; Woodruff, Robert A.; Vasudevan, Gopal; Thompson, Patrick; Chen, Andrew; Petrone, Peter; Booth, Andrew; Madison, Timothy; Bolcar, Matthew; Noecker, M. Charley; Kendrick, Stephen; Melnick, Gary; Tolls, Volker

    2010-01-01

    Three of the recently completed NASA Astrophysics Strategic Mission Concept (ASMC) studies addressed the feasibility of using a Visible Nulling Coronagraph (VNC) as the prime instrument for exoplanet science. The VNC approach is one of the few approaches that works with filled, segmented and sparse or diluted aperture telescope systems and thus spans the space of potential ASMC exoplanet missions. NASA/Goddard Space Flight Center (GSFC) has a well-established effort to develop VNC technologies and has developed an incremental sequence of VNC testbeds to advance the this approach and the technologies associated with it. Herein we report on the continued development of the vacuum Visible Nulling Coronagraph testbed (VNT). The VNT is an ultra-stable vibration isolated testbed that operates under high bandwidth closed-loop control within a vacuum chamber. It will be used to achieve an incremental sequence of three visible light nulling milestones of sequentially higher contrasts of 10(exp 8) , 10(exp 9) and 10(exp 10) at an inner working angle of 2*lambda/D and ultimately culminate in spectrally broadband (>20%) high contrast imaging. Each of the milestones, one per year, is traceable to one or more of the ASMC studies. The VNT uses a modified Mach-Zehnder nulling interferometer, modified with a modified "W" configuration to accommodate a hex-packed MEMS based deformable mirror, a coherent fiber bundle and achromatic phase shifters. Discussed will be the optical configuration laboratory results, critical technologies and the null sensing and control approach.

  1. Signaling Role of Prokineticin 2 on the Estrous Cycle of Female Mice

    PubMed Central

    Xiao, Ling; Zhang, Chengkang; Li, Xiaohan; Gong, Shiaoching; Hu, Renming; Balasubramanian, Ravikumar; Crowley W. Jr., William F.; Hastings, Michael H.; Zhou, Qun-Yong

    2014-01-01

    The possible signaling role of prokineticin 2 (PK2) and its receptor, prokineticin receptor 2 (PKR2), on female reproduction was investigated. First, the expression of PKR2 and its co-localization with estrogen receptor (ERα) in the hypothalamus was examined. Sexually dimorphic expression of PKR2 in the preoptic area of the hypothalamus was observed. Compared to the male mice, there was more widespread PKR2 expression in the preoptic area of the hypothalamus in the female mice. The likely co-expression of PKR2 and ERα in the preoptic area of the hypothalamus was observed. The estrous cycles in female PK2-null, and PKR2-null heterozygous mice, as well as in PK2-null and PKR2-null compound heterozygous mice were examined. Loss of one copy of PK2 or PKR2 gene caused elongated and irregular estrous cycle in the female mice. The alterations in the estrous cycle were more pronounced in PK2-null and PKR2-null compound heterozygous mice. Consistent with these observations, administration of a small molecule PK2 receptor antagonist led to temporary blocking of estrous cycle at the proestrous phase in female mice. The administration of PKR2 antagonist was found to blunt the circulating LH levels. Taken together, these studies indicate PK2 signaling is required for the maintenance of normal female estrous cycles. PMID:24633064

  2. Gsta4 Null Mouse Embryonic Fibroblasts Exhibit Enhanced Sensitivity to Oxidants: Role of 4-Hydroxynonenal in Oxidant Toxicity*

    PubMed Central

    McElhanon, Kevin E.; Bose, Chhanda; Sharma, Rajendra; Wu, Liping; Awasthi, Yogesh C.; Singh, Sharda P.

    2013-01-01

    The alpha class glutathione s-transferase (GST) isozyme GSTA4–4 (EC2.5.1.18) exhibits high catalytic efficiency to-wards 4-hydroxynon-2-enal (4-HNE), a major end product of oxidative stress induced lipid peroxidation. Exposure of cells and tissues to heat, radiation, and chemicals has been shown to induce oxidative stress resulting in elevated concentrations of 4-HNE that can be detrimental to cell survival. Alternatively, at physiological levels 4-HNE acts as a signaling molecule conveying the occurrence of oxidative events initiating the activation of adaptive pathways. To examine the impact of oxidative/electrophilic stress in a model with impaired 4-HNE metabolizing capability, we disrupted the Gsta4 gene that encodes GSTA4–4 in mice. The effect of electrophile and oxidants on embryonic fibroblasts (MEF) isolated from wild type (WT) and Gsta4 null mice were examined. Results indicate that in the absence of GSTA4–4, oxidant-induced toxicity is potentiated and correlates with elevated accumulation of 4-HNE adducts and DNA damage. Treatment of Gsta4 null MEF with 1,1,4-tris(acetyloxy)-2(E)-nonene [4-HNE(Ac)3], a pro-drug form of 4-HNE, resulted in the activation and phosphorylation of the c-jun-N-terminal kinase (JNK), extracellular-signal-regulated kinases (ERK 1/2) and p38 mitogen activated protein kinases (p38 MAPK) accompanied by enhanced cleavage of caspase-3. Interestingly, when recombinant mammalian or invertebrate GSTs were delivered to Gsta4 null MEF, activation of stress-related kinases in 4-HNE(Ac)3 treated Gsta4 null MEF were inversely correlated with the catalytic efficiency of delivered GSTs towards 4-HNE. Our data suggest that GSTA4–4 plays a major role in protecting cells from the toxic effects of oxidant chemicals by attenuating the accumulation of 4-HNE. PMID:24353929

  3. SR-BI protects against endotoxemia in mice through its roles in glucocorticoid production and hepatic clearance

    PubMed Central

    Cai, Lei; Ji, Ailing; de Beer, Frederick C.; Tannock, Lisa R.; van der Westhuyzen, Deneys R.

    2007-01-01

    Septic shock results from an uncontrolled inflammatory response, mediated primarily by LPS. Cholesterol transport plays an important role in the host response to LPS, as LPS is neutralized by lipoproteins and adrenal cholesterol uptake is required for antiinflammatory glucocorticoid synthesis. In this study, we show that scavenger receptor B-I (SR-BI), an HDL receptor that mediates HDL cholesterol ester uptake into cells, is required for the normal antiinflammatory response to LPS-induced endotoxic shock. Despite elevated plasma HDL levels, SR-BI–null mice displayed an uncontrollable inflammatory cytokine response and a markedly higher lethality rate than control mice in response to LPS. In addition, SR-BI–null mice showed a lack of inducible glucocorticoid synthesis in response to LPS, bacterial infection, stress, or ACTH. Glucocorticoid insufficiency in SR-BI–null mice was due to primary adrenal malfunction resulting from deficient cholesterol delivery from HDL. Furthermore, corticosterone supplementation decreased the sensitivity of SR-BI–null mice to LPS. Plasma from control and SR-BI–null mice exhibited a similar ability to neutralize LPS, whereas SR-BI–null mice showed decreased plasma clearance of LPS into the liver and hepatocytes compared with normal mice. We conclude that SR-BI in mice is required for the antiinflammatory response to LPS-induced endotoxic shock, likely through its essential role in facilitating glucocorticoid production and LPS hepatic clearance. PMID:18064300

  4. Double null hamiltonian dynamics and the gravitational degrees of freedom

    NASA Astrophysics Data System (ADS)

    Vickers, J. A.

    2011-12-01

    In this paper we review the Hamiltonian description of General Relativity using a double null foliation. We start by looking at the 2+2 version of geometrodynamics and show the role of the conformal 2-structure of the 2-metric in encoding (through the shear) the 2 gravitational degrees of freedom. In the second part of the paper we consider instead a canonical analysis of a double null 2+2 Hamiltonian description of General Relativity in terms of self-dual 2-forms and the associated SO(3) connection variables. The algebra of first class constraints is obtained and forms a Lie algebra that consists of two constraints that generate diffeomorphisms in the two surface, a constraint that generates diffeomorphisms along the null generators and a constraint that generates self-dual spin and boost transformations.

  5. On the geometry of null hypersurfaces in Minkowski space

    NASA Astrophysics Data System (ADS)

    Navarro, Matias; Palmas, Oscar; Solis, Didier A.

    2014-01-01

    The present work is divided into three parts. First we study the null hypersurfaces of the Minkowski space R1n+2, classifying all rotation null hypersurfaces in R1n+2. In the second part we start our analysis of the submanifold geometry of the null hypersurfaces. In the particular case of the (n+1)-dimensional light cone, we characterize its totally umbilical spacelike hypersurfaces, show the existence of non-totally umbilical ones and give a uniqueness result for the minimal spacelike rotation surfaces in the 3-dimensional light cone. In the third and final part we consider an isolated umbilical point on a spacelike surface immersed in the 3-dimensional light cone of R14 and obtain the differential equation of the principal configuration associated to this point, showing that every classical generic Darbouxian principal configuration appears in this context.

  6. Null but not void: considerations for hypothesis testing.

    PubMed

    Shaw, Pamela A; Proschan, Michael A

    2013-01-30

    Standard statistical theory teaches us that once the null and alternative hypotheses have been defined for a parameter, the choice of the statistical test is clear. Standard theory does not teach us how to choose the null or alternative hypothesis appropriate to the scientific question of interest. Neither does it tell us that in some cases, depending on which alternatives are realistic, we may want to define our null hypothesis differently. Problems in statistical practice are frequently not as pristinely summarized as the classic theory in our textbooks. In this article, we present examples in statistical hypothesis testing in which seemingly simple choices are in fact rich with nuance that, when given full consideration, make the choice of the right hypothesis test much less straightforward. Published 2012. This article is a US Government work and is in the public domain in the USA. PMID:22807023

  7. Unicorns do exist: a tutorial on "proving" the null hypothesis.

    PubMed

    Streiner, David L

    2003-12-01

    Introductory statistics classes teach us that we can never prove the null hypothesis; all we can do is reject or fail to reject it. However, there are times when it is necessary to try to prove the nonexistence of a difference between groups. This most often happens within the context of comparing a new treatment against an established one and showing that the new intervention is not inferior to the standard. This article first outlines the logic of "noninferiority" testing by differentiating between the null hypothesis (that which we are trying to nullify) and the "nill" hypothesis (there is no difference), reversing the role of the null and alternate hypotheses, and defining an interval within which groups are said to be equivalent. We then work through an example and show how to calculate sample sizes for noninferiority studies. PMID:14733457

  8. Fully achromatic nulling interferometer (FANI) for high SNR exoplanet characterization

    NASA Astrophysics Data System (ADS)

    Hénault, François

    2015-09-01

    Space-borne nulling interferometers have long been considered as the best option for searching and characterizing extrasolar planets located in the habitable zone of their parent stars. Solutions for achieving deep starlight extinction are now numerous and well demonstrated. However they essentially aim at realizing an achromatic central null in order to extinguish the star. In this communication is described a major improvement of the technique, where the achromatization process is extended to the entire fringe pattern. Therefore higher Signal-to-noise ratios (SNR) and appreciable simplification of the detection system should result. The basic principle of this Fully achromatic nulling interferometer (FANI) consists in inserting dispersive elements along the arms of the interferometer. Herein this principle is explained and illustrated by a preliminary optical system design. The typical achievable performance and limitations are discussed and some initial tolerance requirements are also provided.

  9. Statefinder hierarchy: An extended null diagnostic for concordance cosmology

    SciTech Connect

    Arabsalmani, Maryam; Sahni, Varun

    2011-02-15

    We show how higher derivatives of the expansion factor can be developed into a null diagnostic for concordance cosmology ({Lambda}CDM). It is well known that the Statefinder - the third derivative of the expansion factor written in dimensionless form, a{sup (3)}/aH{sup 3}, equals unity for {Lambda}CDM. We generalize this result and demonstrate that the hierarchy, a{sup (n)}/aH{sup n}, can be converted to a form that stays pegged at unity in concordance cosmology. This remarkable property of the Statefinder hierarchy enables it to be used as an extended null diagnostic for the cosmological constant. The Statefinder hierarchy combined with the growth rate of matter perturbations defines a composite null diagnostic which can distinguish evolving dark energy from {Lambda}CDM.

  10. Biological and genetic properties of the p53 null preneoplastic mammary epithelium

    NASA Technical Reports Server (NTRS)

    Medina, Daniel; Kittrell, Frances S.; Shepard, Anne; Stephens, L. Clifton; Jiang, Cheng; Lu, Junxuan; Allred, D. Craig; McCarthy, Maureen; Ullrich, Robert L.

    2002-01-01

    The absence of the tumor suppressor gene p53 confers an increased tumorigenic risk for mammary epithelial cells. In this report, we describe the biological and genetic properties of the p53 null preneoplastic mouse mammary epithelium in a p53 wild-type environment. Mammary epithelium from p53 null mice was transplanted serially into the cleared mammary fat pads of p53 wild-type BALB/c female to develop stable outgrowth lines. The outgrowth lines were transplanted for 10 generations. The outgrowths were ductal in morphology and progressed through ductal hyperplasia and ductal carcinoma in situ before invasive cancer. The preneoplastic outgrowth lines were immortal and exhibited activated telomerase activity. They are estrogen and progesterone receptor-positive, and aneuploid, and had various levels of tumorigenic potential. The biological and genetic properties of these lines are distinct from those found in most hyperplastic alveolar outgrowth lines, the form of mammary preneoplasia occurring in most traditional models of murine mammary tumorigenesis. These results indicate that the preneoplastic cell populations found in this genetically engineered model are similar in biological properties to a subset of precurser lesions found in human breast cancer and provide a unique model to identify secondary events critical for tumorigenicity and invasiveness.

  11. Magnetoacoustic Waves in Stratified Atmospheres with a Magnetic Null Point

    NASA Astrophysics Data System (ADS)

    Tarr, Lucas A.; Linton, Mark; Leake, James E.

    2016-05-01

    Magnetic fields strongly modify the propagation of MHD waves from the photosphere to the low corona, as can be shown exactly for the most simple case of a uniform magnetic field and isothermally stratrified atmosphere. For slightly more realistic scenarios, where both the atmospheric parameters and the magnetic field vary spatially, the linear MHD equations typically cannot be solved analytically. We use the Lagrangian Remap code--a nonlinear, shock-capturing MHD code--to study the propagation of initially acoustic wavepackets through a model 2D atmosphere that includes a gravitationally stratified chromosphere, transition region, and low corona. The magnetic field is formed by three photospheric concentrations and includes a single magnetic null point, resulting in an inhomogeneous system with a magnetic dome topology. A portion of an introduced wavepacket will refract toward the null due to the varying Alfven speed. Waves incident on the equipartition contour surrounding the null, where the sound and Alfven speeds coincide, partially transmit, reflect, and mode convert between branches of the local dispersion relation. Outward propagating slow modes generated during conversion become strongly concentrated along the set of field lines passing near the null. Acoustic energy is beamed back downwards towards each photospheric foot point, and upwards along one separatrix that exits the top of the numerical domain. Changes in the dominant restoring force for the wavepacket, between the Lorentz and pressure gradient forces, lead to a buildup of current density along topologically important features of the system (the null point and its four separatrices) and can drive reconnection at the null point itself. Ohmic dissipation of the currents locally heats the plasma. We find that the amount of current accumulation depends on where the centroid of a wavepacket initial crosses the photosphere, but does not simply coincide with regions of open versus closed magnetic field or

  12. Retention of crab larvae in a coastal null zone

    NASA Astrophysics Data System (ADS)

    Tilburg, Charles E.; Dittel, Ana I.; Epifanio, Charles E.

    2007-05-01

    Alongshelf transport in the southern Middle Atlantic Bight is forced by buoyancy-driven currents originating in three large estuaries along the bight. These currents are strongest in the coastal ocean near the southern terminus of each estuary, while the analogous region on the northern side is characterized by weak subtidal flow. We used a combination of field observations and numerical modeling to test the hypothesis that these regions of weak subtidal flow are coastal null zones that serve as retention areas for larvae. The field study consisted of a four-day, shipboard investigation of the distribution of blue crab larvae ( Callinectes sapidus) near the mouth of Delaware Bay (˜39°N, 75°W) in late summer, 2004. Hydrographic surveys of the study site were conducted with a hull-mounted, surface-measuring system. Results showed a sharp boundary between the null zone and the buoyancy-driven current to the south. Blue crab larvae were collected in surface plankton tows along a 30-km transect that encompassed these two areas. Stations with higher densities of larvae were clustered in the null zone during both ebb and flood tides. A numerical model was used to examine the physical mechanisms responsible for the observed distribution. Model results agreed with the field survey and showed that simulated larvae are aggregated in the null zone. The simulations also demonstrated that larvae spawned within the null zone have a much greater probability of settling in juvenile nursery habitat within the bay. The close agreement between field and model results provides consistent support for the hypothesis that coastal null zones associated with the buoyancy-driven circulation of large estuaries may allow retention of larvae in the vicinity of the natal spawning population.

  13. N-ethyl-N-nitrosourea-induced null mutation at the mouse Car-2 locus: an animal model for human carbonic anhydrase II deficiency syndrome.

    PubMed Central

    Lewis, S E; Erickson, R P; Barnett, L B; Venta, P J; Tashian, R E

    1988-01-01

    Electrophoretic screening of (C57BL/6J x DBA/2J)F1 progeny of male mice treated with N-ethyl-N-nitrosourea revealed a mouse that lacked the paternal carbonic anhydrase II (CA II). Breeding tests showed that this trait was heritable and due to a null mutation at the Car-2 locus on chromosome 3. Like humans with the same inherited enzyme defect, animals homozygous for the new null allele are runted and have renal tubular acidosis. However, the prominent osteopetrosis found in humans with CA II deficiency could not be detected even in very old homozygous null mice. A molecular analysis of the deficient mice shows that the mutant gene is not deleted and is transcribed. The CA II protein, which is normally expressed in most tissues, could not be detected by immunodiffusion analysis in any tissues of the CA II-deficient mice, suggesting a nonsense or a missense mutation at the Car-2 locus. Images PMID:3126501

  14. Adaptive Nulling for the Terrestrial Planet Finder Interferometer

    NASA Technical Reports Server (NTRS)

    Jeganathan, Muthu; Hirai, Akiko; Lay, Oliver P.; Peters, Robert D.

    2006-01-01

    Deep, stable starlight nulls are needed for the direct detection of Earth-like planets and require careful control of the intensity and phases of the beams that are being combined. We are testing a novel compensator based on a deformable mirror to correct the intensity and phase at each wavelength and polarization across the nulling bandwidth. We have successfully demonstrated intensity and phase control using a deformable mirror across a 100nm wide band in the near-IR, and are in the process of conducting experiments in the mid-IR wavelengths. This paper covers the current results and in the mid-IR.

  15. Null geodesics in a magnetically charged stringy black hole spacetime

    NASA Astrophysics Data System (ADS)

    Kuniyal, Ravi Shankar; Uniyal, Rashmi; Nandan, Hemwati; Purohit, K. D.

    2016-04-01

    We study the null geodesics of a four-dimensional magnetic charged black hole spacetime arising in string theory. The behaviour of effective potential in view of the different values of black hole parameters are analysed in the equatorial plane. The possible orbits for null geodesics are also discussed in view of the different values of the impact parameter. We have also calculated the frequency shift of photons in this spacetime. The results are compared to those obtained for the electrically charged stringy black hole spacetime and the Schwarzschild black hole spacetime in general relativity.

  16. Differential expression of pancreatic protein and chemosensing receptor mRNAs in NKCC1-null intestine

    PubMed Central

    Bradford, Emily M; Vairamani, Kanimozhi; Shull, Gary E

    2016-01-01

    AIM: To investigate the intestinal functions of the NKCC1 Na+-K+-2Cl cotransporter (SLC12a2 gene), differential mRNA expression changes in NKCC1-null intestine were analyzed. METHODS: Microarray analysis of mRNA from intestines of adult wild-type mice and gene-targeted NKCC1-null mice (n = 6 of each genotype) was performed to identify patterns of differential gene expression changes. Differential expression patterns were further examined by Gene Ontology analysis using the online Gorilla program, and expression changes of selected genes were verified using northern blot analysis and quantitative real time-polymerase chain reaction. Histological staining and immunofluorescence were performed to identify cell types in which upregulated pancreatic digestive enzymes were expressed. RESULTS: Genes typically associated with pancreatic function were upregulated. These included lipase, amylase, elastase, and serine proteases indicative of pancreatic exocrine function, as well as insulin and regenerating islet genes, representative of endocrine function. Northern blot analysis and immunohistochemistry showed that differential expression of exocrine pancreas mRNAs was specific to the duodenum and localized to a subset of goblet cells. In addition, a major pattern of changes involving differential expression of olfactory receptors that function in chemical sensing, as well as other chemosensing G-protein coupled receptors, was observed. These changes in chemosensory receptor expression may be related to the failure of intestinal function and dependency on parenteral nutrition observed in humans with SLC12a2 mutations. CONCLUSION: The results suggest that loss of NKCC1 affects not only secretion, but also goblet cell function and chemosensing of intestinal contents via G-protein coupled chemosensory receptors. PMID:26909237

  17. Testing the null hypothesis: the forgotten legacy of Karl Popper?

    PubMed

    Wilkinson, Mick

    2013-01-01

    Testing of the null hypothesis is a fundamental aspect of the scientific method and has its basis in the falsification theory of Karl Popper. Null hypothesis testing makes use of deductive reasoning to ensure that the truth of conclusions is irrefutable. In contrast, attempting to demonstrate the new facts on the basis of testing the experimental or research hypothesis makes use of inductive reasoning and is prone to the problem of the Uniformity of Nature assumption described by David Hume in the eighteenth century. Despite this issue and the well documented solution provided by Popper's falsification theory, the majority of publications are still written such that they suggest the research hypothesis is being tested. This is contrary to accepted scientific convention and possibly highlights a poor understanding of the application of conventional significance-based data analysis approaches. Our work should remain driven by conjecture and attempted falsification such that it is always the null hypothesis that is tested. The write up of our studies should make it clear that we are indeed testing the null hypothesis and conforming to the established and accepted philosophical conventions of the scientific method. PMID:23249368

  18. Circumpulsar Asteroids: Inferences from Nulling Statistics and High Energy Correlations

    NASA Astrophysics Data System (ADS)

    Shannon, Ryan; Cordes, J. M.

    2006-12-01

    We have proposed that some classes of radio pulsar variability are associated with the entry of neutral asteroidal material into the pulsar magnetosphere. The region surrounding neutron stars is polluted with supernova fall-back material, which collapses and condenses into an asteroid-bearing disk that is stable for millions of years. Over time, collisional and radiative processes cause the asteroids to migrate inward until they are heated to the point of ionization. For older and cooler pulsars, asteroids ionize within the large magnetospheres and inject a sufficient amount of charged particles to alter the electrodynamics of the gap regions and modulate emission processes. This extrinsic model unifies many observed phenomena of variability that occur on time scales that are disparate with the much shorter time scales associated with pulsars and their magnetospheres. One such type of variability is nulling, in which certain pulsars exhibit episodes of quiescence that for some objects may be as short as a few pulse periods, but, for others, is longer than days. Here, in the context of this model, we examine the nulling phenomenon. We analyze the relationship between in-falling material and the statistics of nulling. In addition, as motivation for further high energy observations, we consider the relationship between the nulling and other magnetospheric processes.

  19. Reassessing the Null-Subject Parameter in Second Language Acquisition.

    ERIC Educational Resources Information Center

    Lantolf, James P.

    A study is presented that examines the null-subject parameter (NSP) and that seeks to attain the following objectives: (1) to assess the validity of the implicational hierarchy for the NSP, especially as proposed by Liceras (1989); and (2) to determine if there is any evidence to support the theory of the Weaker Logical Problem of Acquisition…

  20. Self-Nulling Beam Combiner Using No External Phase Inverter

    NASA Technical Reports Server (NTRS)

    Bloemhof, Eric E.

    2010-01-01

    A self-nulling beam combiner is proposed that completely eliminates the phase inversion subsystem from the nulling interferometer, and instead uses the intrinsic phase shifts in the beam splitters. Simplifying the flight instrument in this way will be a valuable enhancement of mission reliability. The tighter tolerances on R = T (R being reflection and T being transmission coefficients) required by the self-nulling configuration actually impose no new constraints on the architecture, as two adaptive nullers must be situated between beam splitters to correct small errors in the coatings. The new feature is exploiting the natural phase shifts in beam combiners to achieve the 180 phase inversion necessary for nulling. The advantage over prior art is that an entire subsystem, the field-flipping optics, can be eliminated. For ultimate simplicity in the flight instrument, one might fabricate coatings to very high tolerances and dispense with the adaptive nullers altogether, with all their moving parts, along with the field flipper subsystem. A single adaptive nuller upstream of the beam combiner may be required to correct beam train errors (systematic noise), but in some circumstances phase chopping reduces these errors substantially, and there may be ways to further reduce the chop residuals. Though such coatings are beyond the current state of the art, the mechanical simplicity and robustness of a flight system without field flipper or adaptive nullers would perhaps justify considerable effort on coating fabrication.

  1. Traversable wormholes: Minimum violation of the null energy condition revisited

    SciTech Connect

    Zaslavskii, O. B.

    2007-08-15

    It was argued in literature that traversable wormholes can exist with an arbitrarily small violation of null energy conditions. I show that if the amount of exotic material near the wormhole throat tends to zero, either this leads to a horn instead of a wormhole or the throat approaches the horizon in such a way that infinitely large stresses develop on the throat.

  2. Do Null Subjects (Mis-)Trigger Pro-Drop Grammars?

    ERIC Educational Resources Information Center

    Frazier, Lyn

    2015-01-01

    Native speakers of English regularly hear sentences without overt subjects. Nevertheless, they maintain a [[superscript -]pro] grammar that requires sentences to have an overt subject. It is proposed that listeners of English recognize that speakers reduce predictable material and thus attribute null subjects to this process, rather than changing…

  3. White-Light Nulling Interferometers for Detecting Planets

    NASA Technical Reports Server (NTRS)

    Mennesson, Bertrand; Serabyn, Eugene; Shao, Michael; Levine, Bruce

    2004-01-01

    A report proposes the development of a white-light nulling interferometer to be used in conjunction with a singleaperture astronomical telescope that would be operated in outer space. When such a telescope is aimed at a given star, the interferometer would suppress the light of that star while passing enough light from planets (if any) orbiting the star, to enable imaging or spectroscopic examination of the planets. In a nulling interferometer, according to the proposal, scattered light would be suppressed by spatial filtering in an array of single-mode optical fibers rather than by requiring optical surfaces to be accurate within 1/4,000 wavelength as in a coronagraph or an apodized telescope. As a result, angstrom-level precision would be needed in only the small nulling combiner, and not in large, meter-sized optics. The nulling interferometer could work as an independent instrument in space or in conjunction with a coronagraphic system to detect planets outside our solar system.

  4. Null Objects in Second Language Acquisition: Grammatical vs. Performance Models

    ERIC Educational Resources Information Center

    Zyzik, Eve C.

    2008-01-01

    Null direct objects provide a favourable testing ground for grammatical and performance models of argument omission. This article examines both types of models in order to determine which gives a more plausible account of the second language data. The data were collected from second language (L2) learners of Spanish by means of four oral…

  5. Null Lens Assembly for X-Ray Mirror Segments

    NASA Technical Reports Server (NTRS)

    Robinson, David W.

    2011-01-01

    A document discusses a null lens assembly that allows laser interferometry of 60 deg. slumped glass mirror segments used in x-ray mirrors. The assembly consists of four lenses in precise alignment to each other, with incorporated piezoelectric nanometer stepping actuators to position the lenses in six degrees of freedom for positioning relative to each other.

  6. Progress in broadband infrared nulling technology for TPF

    NASA Technical Reports Server (NTRS)

    Wallace, J. Kent; Brown, Ken; Bartos, Randall; Gappinger, Robert; Loya, Frank; Macdonald, Dan; Moser, Steve; Negron, John

    2005-01-01

    TPF-I has set for itself a host of challenging technical milestones along its path to demonstrating the feasibility of infrared nulling for planet detection Progress in each of these areas of technical development will be reviewed as well as progress in meeting the overarching technical milestones.

  7. Null point of discrimination in crustacean polarisation vision.

    PubMed

    How, Martin J; Christy, John; Roberts, Nicholas W; Marshall, N Justin

    2014-07-15

    The polarisation of light is used by many species of cephalopods and crustaceans to discriminate objects or to communicate. Most visual systems with this ability, such as that of the fiddler crab, include receptors with photopigments that are oriented horizontally and vertically relative to the outside world. Photoreceptors in such an orthogonal array are maximally sensitive to polarised light with the same fixed e-vector orientation. Using opponent neural connections, this two-channel system may produce a single value of polarisation contrast and, consequently, it may suffer from null points of discrimination. Stomatopod crustaceans use a different system for polarisation vision, comprising at least four types of polarisation-sensitive photoreceptor arranged at 0, 45, 90 and 135 deg relative to each other, in conjunction with extensive rotational eye movements. This anatomical arrangement should not suffer from equivalent null points of discrimination. To test whether these two systems were vulnerable to null points, we presented the fiddler crab Uca heteropleura and the stomatopod Haptosquilla trispinosa with polarised looming stimuli on a modified LCD monitor. The fiddler crab was less sensitive to differences in the degree of polarised light when the e-vector was at -45 deg than when the e-vector was horizontal. In comparison, stomatopods showed no difference in sensitivity between the two stimulus types. The results suggest that fiddler crabs suffer from a null point of sensitivity, while stomatopods do not. PMID:24737768

  8. The appearance, motion, and disappearance of three-dimensional magnetic null points

    SciTech Connect

    Murphy, Nicholas A.; Parnell, Clare E.; Haynes, Andrew L.

    2015-10-15

    While theoretical models and simulations of magnetic reconnection often assume symmetry such that the magnetic null point when present is co-located with a flow stagnation point, the introduction of asymmetry typically leads to non-ideal flows across the null point. To understand this behavior, we present exact expressions for the motion of three-dimensional linear null points. The most general expression shows that linear null points move in the direction along which the magnetic field and its time derivative are antiparallel. Null point motion in resistive magnetohydrodynamics results from advection by the bulk plasma flow and resistive diffusion of the magnetic field, which allows non-ideal flows across topological boundaries. Null point motion is described intrinsically by parameters evaluated locally; however, global dynamics help set the local conditions at the null point. During a bifurcation of a degenerate null point into a null-null pair or the reverse, the instantaneous velocity of separation or convergence of the null-null pair will typically be infinite along the null space of the Jacobian matrix of the magnetic field, but with finite components in the directions orthogonal to the null space. Not all bifurcating null-null pairs are connected by a separator. Furthermore, except under special circumstances, there will not exist a straight line separator connecting a bifurcating null-null pair. The motion of separators cannot be described using solely local parameters because the identification of a particular field line as a separator may change as a result of non-ideal behavior elsewhere along the field line.

  9. Thermodynamical interpretation of the geometrical variables associated with null surfaces

    NASA Astrophysics Data System (ADS)

    Chakraborty, Sumanta; Padmanabhan, T.

    2015-11-01

    The emergent gravity paradigm interprets gravitational field equations as describing the thermodynamic limit of the underlying statistical mechanics of microscopic degrees of freedom of the spacetime. The connection is established by attributing a heat density T s to the null surfaces where T is the appropriate Davies-Unruh temperature and s is the entropy density. The field equations can be obtained from a thermodynamic variational principle which extremizes the total heat density of all null surfaces. The explicit form of s determines the nature of the theory. We explore the consequences of this paradigm for an arbitrary null surface and highlight the thermodynamic significance of various geometrical quantities. In particular, we show that (a) a conserved current, associated with the time development vector in a natural fashion, has direct thermodynamic interpretation in all Lanczos-Lovelock models of gravity; (b) one can generalize the notion of gravitational momentum, introduced in T. Padmanabhan, [arXiv:1506.03814] to all Lanczos-Lovelock models of gravity such that the conservation of the total momentum leads to the relevant field equations; (c) the thermodynamic variational principle which leads to the field equations of gravity can also be expressed in terms of the gravitational momentum in all Lanczos-Lovelock models; and (d) three different projections of gravitational momentum related to an arbitrary null surface in the spacetime lead to three different equations, all of which have thermodynamic interpretation. The first one reduces to a Navier-Stokes equation for the transverse drift velocity. The second can be written as a thermodynamic identity T d S =d E +P d V . The third describes the time evolution of the null surface in terms of suitably defined surface and bulk degrees of freedom. The implications are discussed.

  10. Early Life Inorganic Lead Exposure Induces Testicular Teratoma and Renal and Urinary Bladder Preneoplasia in Adult Metallothionein-Knockout Mice but Not in Wild Type Mice

    PubMed Central

    Tokar, Erik J.; Diwan, Bhalchandra A.; Waalkes, Michael P.

    2010-01-01

    Inorganic lead compounds are carcinogenic in animals and have carcinogenic potential in humans. In mice, lead (Pb) is a transplacental carcinogen in the kidney. Metallothionein (MT) is a metal-binding protein that can reduce the toxicity of various metals, including Pb, either by direct sequestration or as an antioxidant for metals that generate reactive oxygen species. Although MT appears to reduce Pb carcinogenicity in adult mice it is unknown how MT deficiency may affect Pb carcinogenicity from early life exposure. Thus, groups (n = 10) of pregnant MT-I/II double knockout (MT-null) or 129/SVJ MT wild type (WT) mice were exposed to Pb acetate in the drinking water (0, 2000, 4000 ppm Pb) from gestation day 8 through birth and during lactation. Maternal drinking water Pb exposure continued to weaning at 4 weeks of age and the male offspring were then directly exposed to Pb until 8 weeks of age and observed until 2 years old. High dose (4000 ppm) but not low dose (2000 ppm) Pb reduced survival in the latter part of the study in both MT-null and WT mice. In MT-null mice, but not WT, early life Pb exposure caused a dose-related increase in testicular teratomas, to a maximum incidence of 28% compared to control (4%). Pb-induced renal cystic hyperplasia, considered preneoplastic, were a prominent occurrence in MT-null mice but nearly absent in WT mice. Pb dose-related increases in renal cystic hyperplasia occurred in adult MT-null with early life exposure with maximal incidence of 52%. Pb-treated MT-null mice also showed dose-related increases in urinary bladder hyperplasia with occasional papilloma that were absent in WT mice. Thus, MT deficiency made mice more sensitive to early life Pb exposure with regard to testes tumors, and renal and urinary bladder preneoplastic lesions. PMID:20600549

  11. Metabolomics of the interaction between PPAR-α and age in the PPAR-α-null mouse

    PubMed Central

    Atherton, Helen J; Gulston, Melanie K; Bailey, Nigel J; Cheng, Kian-Kai; Zhang, Wen; Clarke, Kieran; Griffin, Julian L

    2009-01-01

    Regulation between the fed and fasted states in mammals is partially controlled by peroxisome proliferator-activated receptor-α (PPAR-α). Expression of the receptor is high in the liver, heart and skeletal muscle, but decreases with age. A combined 1H nuclear magnetic resonance (NMR) spectroscopy and gas chromatography-mass spectrometry metabolomic approach has been used to examine metabolism in the liver, heart, skeletal muscle and adipose tissue in PPAR-α-null mice and wild-type controls during ageing between 3 and 13 months. For the PPAR-α-null mouse, multivariate statistics highlighted hepatic steatosis, reductions in the concentrations of glucose and glycogen in both the liver and muscle tissue, and profound changes in lipid metabolism in each tissue, reflecting known expression targets of the PPAR-α receptor. Hepatic glycogen and glucose also decreased with age for both genotypes. These findings indicate the development of age-related hepatic steatosis in the PPAR-α-null mouse, with the normal metabolic changes associated with ageing exacerbating changes associated with genotype. Furthermore, the combined metabolomic and multivariate statistics approach provides a robust method for examining the interaction between age and genotype. PMID:19357638

  12. Serum metabolite profiles are altered by erlotinib treatment and the integrin α1-null genotype, but not by post traumatic osteoarthritis

    PubMed Central

    Mickiewicz, Beata; Shin, Sung Y.; Pozzi, Ambra; Vogel, Hans J.; Clark, Andrea L.

    2016-01-01

    The risk of developing post traumatic osteoarthritis (PTOA) following joint injury is high. Furthering our understanding of the molecular mechanisms underlying PTOA and/or identifying novel biomarkers for early detection may help improve treatment outcomes. Increased expression of integrin α1β1 and inhibition of epidermal growth factor receptor (EGFR) signaling protect the knee from spontaneous OA, however the impact of the integrin α1β1/EGFR axis on PTOA is currently unknown. We sought to determine metabolic changes in serum samples collected from wild type and integrin α1-null mice that underwent surgery to destabilize the medial meniscus and were treated with the EGFR inhibitor erlotinib. Following 1H nuclear magnetic resonance spectroscopy we generated multivariate statistical models that distinguished between the metabolic profiles of erlotinib- versus vehicle-treated mice, and the integrin α1-null versus wild type mouse genotype. Our results show the sex dependent effects of erlotinib treatment and highlight glutamine as a metabolite that counteracts this treatment. Furthermore, we identified a set of metabolites associated with increased reactive oxygen species production, susceptibility to OA and regulation of TRP channels in α1-null mice. Our study indicates that systemic pharmacological and genetic factors have a greater effect on serum metabolic profiles than site specific factors such as surgery. PMID:26784366

  13. Serum Metabolite Profiles Are Altered by Erlotinib Treatment and the Integrin α1-Null Genotype but Not by Post-Traumatic Osteoarthritis.

    PubMed

    Mickiewicz, Beata; Shin, Sung Y; Pozzi, Ambra; Vogel, Hans J; Clark, Andrea L

    2016-03-01

    The risk of developing post-traumatic osteoarthritis (PTOA) following joint injury is high. Furthering our understanding of the molecular mechanisms underlying PTOA and/or identifying novel biomarkers for early detection may help to improve treatment outcomes. Increased expression of integrin α1β1 and inhibition of epidermal growth factor receptor (EGFR) signaling protect the knee from spontaneous OA; however, the impact of the integrin α1β1/EGFR axis on PTOA is currently unknown. We sought to determine metabolic changes in serum samples collected from wild-type and integrin α1-null mice that underwent surgery to destabilize the medial meniscus and were treated with the EGFR inhibitor erlotinib. Following (1)H nuclear magnetic resonance spectroscopy, we generated multivariate statistical models that distinguished between the metabolic profiles of erlotinib- versus vehicle-treated mice and the integrin α1-null versus wild-type mouse genotype. Our results show the sex-dependent effects of erlotinib treatment and highlight glutamine as a metabolite that counteracts this treatment. Furthermore, we identified a set of metabolites associated with increased reactive oxygen species production, susceptibility to OA, and regulation of TRP channels in α1-null mice. Our study indicates that systemic pharmacological and genetic factors have a greater effect on serum metabolic profiles than site-specific factors such as surgery. PMID:26784366

  14. The effect of Clostridium perfringens type C strain CN3685 and its isogenic beta toxin null mutant in goats.

    PubMed

    Garcia, J P; Beingesser, J; Fisher, D J; Sayeed, S; McClane, B A; Posthaus, H; Uzal, F A

    2012-06-15

    Clostridium perfringens type C is an important cause of enteritis and/or enterocolitis in several animal species, including pigs, sheep, goats, horses and humans. The disease is a classic enterotoxemia and the enteric lesions and associated systemic effects are thought to be caused primarily by beta toxin (CPB), one of two typing toxins produced by C. perfringens type C. This has been demonstrated recently by fulfilling molecular Koch's postulates in rabbits and mice. We present here an experimental study to fulfill these postulates in goats, a natural host of C. perfringens type C disease. Nine healthy male or female Anglo Nubian goat kids were inoculated with the virulent C. perfringens type C wild-type strain CN3685, an isogenic CPB null mutant or a strain where the cpb null mutation had been reversed. Three goats inoculated with the wild-type strain presented abdominal pain, hemorrhagic diarrhea, necrotizing enterocolitis, pulmonary edema, hydropericardium and death within 24h of inoculation. Two goats inoculated with the CPB null mutant and two goats inoculated with sterile culture media (negative controls) remained clinically healthy during 24h after inoculation and no gross or histological abnormalities were observed in the tissues of any of them. Reversal of the null mutation to partially restore CPB production also increased virulence; 2 goats inoculated with this reversed mutant presented clinical and pathological changes similar to those observed in goats inoculated with the wild-type strain, except that spontaneous death was not observed. These results indicate that CPB is required for C. perfringens type C to induce disease in goats, supporting a key role for this toxin in natural C. perfringens type C disease pathogenesis. PMID:22296994

  15. The effect of Clostridium perfringens type C strain CN3685 and its isogenic beta toxin null mutant in goats

    PubMed Central

    Garcia, J. P.; Beingesser, J.; Fisher, D. J.; Sayeed, S.; McClane, B. A.; Posthaus, H.; Uzal, F. A.

    2012-01-01

    Clostridium perfringens type C is an important cause of enteritis and/or enterocolitis in several animal species, including pigs, sheep, goats, horses and humans. The disease is a classic enterotoxemia and the enteric lesions and associated systemic effects are thought to be caused primarily by beta toxin (CPB), one of two typing toxins produced by C. perfringens type C. This has been demonstrated recently by fulfilling molecular Koch’s postulates in rabbits and mice. We present here an experimental study to fulfill these postulates in goats, a natural host of C. perfringens type C disease. Nine healthy male or female Anglo Nubian goat kids were inoculated with the virulent C. perfringens type C wild-type strain CN3685, an isogenic CPB null mutant or a strain where the cpb null mutation had been reversed. Three goats inoculated with the wild-type strain presented abdominal pain, hemorrhagic diarrhea, necrotizing enterocolitis, pulmonary edema, hydropericardium and death within 24 h of inoculation. Two goats inoculated with the CPB null mutant and two goats inoculated with sterile culture media (negative controls) remained clinically healthy during 24 h after inoculation and no gross or histological abnormalities were observed in the tissues of any of them. Reversal of the null mutation to partially restore CPB production also increased virulence; 2 goats inoculated with this reversed mutant presented clinical and pathological changes similar to those observed in goats inoculated with the wild-type strain, except that spontaneous death was not observed. These results indicate that CPB is required for C. perfringens type C to induce disease in goats, supporting a key role for this toxin in natural C. perfringens type C disease pathogenesis. PMID:22296994

  16. Null Mutations of NT-3 and Bax Affect Trigeminal Ganglion Cell Number but Not Brainstem Barrelette Pattern Formation

    PubMed Central

    Mosconi, Tony; Arends, J.J.; Jacquin, Mark F.

    2014-01-01

    Trigeminal ganglion (TG) neurons innervate the grid-like array of whisker follicles on the face of the mouse. Central TG axons project to the trigeminal (V) brainstem nuclear complex, including the nucleus principalis (PrV), and the spinal subnucleus interpolaris (SpVi), where they innervate barrelettes that are organized in a pattern that recapitulates the whisker pattern on the face. Neurotrophin-3 (NT-3) supports a population of TG cells that supply slowly adapting mechanoreceptors in the whisker pad. We examined mice at embryonic day 17 (E17) and on the day of birth (P0) with null mutations of NT-3, Bax, a proapoptotic gene associated with naturally occurring cell death, and Bax/NT-3 double knockout mutants to determine if: 1) the number of TG cells would be reduced; 2) eliminating the Bax gene would rescue the NT-3 dependent neurons; and 3) the central projections of the rescued axons in the Bax/NT-3 double knockout mice would fail to develop the barrelette patterns in the PrV and SpVi subnuclei. In mice at E17, NT-3−/− mutants had 65% fewer TG neurons than found in age matched wild-type (WT) mice, and at P0, the number was reduced by 55% (p < 0.001 for both). Bax null mutant mice at E17 had 132% of the WT number of TG cells (p < 0.001), although the numbers returned to WT levels by P0. Bax/NT-3 double knockout mice at E17 had TG cell numbers equal to those seen in WT, but the double knockout failed to retain WT TG neuron numbers in P0 mice (39% fewer cells; p < 0.001). In all cases of reduced experimental neuron numbers, and in the E17 Bax−/− mice with supernumerary cells, the barrelette patterns in the PrV and SpVi were normal. Only a slight qualitative reduction in overall barrelette field area and clarity of barrelettes were seen. These results suggest that NT-3 is not necessary for barrelette pattern formation in the brainstem. PMID:23614607

  17. Impaired Lymphocytes Development and Xenotransplantation of Gastrointestinal Tumor Cells in Prkdc-Null SCID Zebrafish Model.

    PubMed

    Jung, In Hye; Chung, Yong-Yoon; Jung, Dawoon E; Kim, Young Jin; Kim, Do Hee; Kim, Kyung-Sik; Park, Seung Woo

    2016-08-01

    Severe combined immunodeficiency (SCID) mice have widely been used as hosts for human tumor cell xenograft study. This animal model, however, is labor intensive. As zebrafish is largely emerging as a promising model system for studying human diseases including cancer, developing efficient immunocompromised strains for tumor xenograft study are also demanded in zebrafish. Here, we have created the Prkdc-null SCID zebrafish model which provides the stable immune-deficient background required for xenotransplantation of tumor cell. In this study, the two transcription activator-like effector nucleases that specifically target the exon3 of the zebrafish Prkdc gene were used to induce a frame shift mutation, causing a complete knockout of the gene function. The SCID zebrafish showed susceptibility to spontaneous infection, a well-known phenotype found in the SCID mutation. Further characterization revealed that the SCID zebrafish contained no functional T and B lymphocytes which reflected the phenotypes identified in the mice SCID model. Intraperitoneal injection of human cancer cells into the adult SCID zebrafish clearly showed tumor cell growth forming into a solid mass. Our present data show the suitability of using the SCID zebrafish strain for xenotransplantation experiments, and in vivo monitoring of the tumor cell growth in the zebrafish demonstrates use of the animal model as a new platform of tumor xenograft study. PMID:27566103

  18. Null fluids: A new viewpoint of Galilean fluids

    NASA Astrophysics Data System (ADS)

    Banerjee, Nabamita; Dutta, Suvankar; Jain, Akash

    2016-05-01

    In this article, we study a Galilean fluid with a conserved U (1 ) current up to anomalies. We construct a relativistic system, which we call a null fluid and show that it is in one-to-one correspondence with a Galilean fluid living in one lower dimension. The correspondence is based on light cone reduction, which is known to reduce the Poincaré symmetry of a theory to Galilean in one lower dimension. We show that the proposed null fluid and the corresponding Galilean fluid have exactly same symmetries, thermodynamics, constitutive relations, and equilibrium partition to all orders in the derivative expansion. We also devise a mechanism to introduce U (1 ) anomaly in even dimensional Galilean theories using light cone reduction, and study its effect on the constitutive relations of a Galilean fluid.

  19. Time travel in transformation optics: Metamaterials with closed null geodesics

    NASA Astrophysics Data System (ADS)

    Boston, S. Reece

    2015-06-01

    We apply the methods of transformation optics to theoretical descriptions of spacetimes that support closed null geodesic curves. The metric used is based on frame dragging spacetimes, such as the van Stockum dust or the Kerr black hole. Through transformation optics, this metric is analogous to a material that in theory should allow for communication between past and future. Presented herein is a derivation and description of the spacetime and the resulting permeability, permittivity, and magnetoelectric couplings that a material would need in order for light in the material to follow closed null geodesics. We also address the paradoxical implications of such a material and demonstrate why such a material would not actually result in a violation of causality. A full derivation of the Plebanski equations is also included.

  20. Two new molecular bases for the Dombrock null phenotype.

    PubMed

    Rios, Maria; Storry, Jill R; Hue-Roye, Kim; Chung, Amy; Reid, Marion E

    2002-06-01

    Red blood cells (RBCs) with the Do(null) phenotype lack all antigens in the Dombrock blood group system, i.e. Do(a), Do(b), Gy(a), Hy and Jo(a). Sequence analysis of DNA from one proband with the Do(null) phenotype revealed a single nucleotide mutation of t to c in the donor splice site of DO (IVS1 + 2t > c), with outsplicing of exon 2. Analysis of a second proband revealed a homozygous nonsense mutation 442 C > T in exon 2 predicting a premature stop codon (Gln148 Stop). The molecular bases described in these two probands provide an explanation for the lack of Do glycoprotein on their RBCs. PMID:12028057

  1. Modifications of the Schwarzschild null geodesics in effective field theories

    SciTech Connect

    Ahmadi, N.

    2009-12-15

    In this paper the dynamics of Schwarzschild null geodesics in the context of low-energy effective field theories incorporating some interactions violating the equivalence principle is examined. Nonperturbed geodesics are expressed in terms of a convenient set of constants called orbital elements. The modifications introduced by the effective interactions are treated as small perturbations, then the method of variation of parameters is employed to find the evolution of the orbital elements for the true worldlines. We next focus our discussion on the geometry of nondispersive photon orbits and highlight the importance of different orbital elements in long-term change of the orbit. This calculation shows that nondispersive forces acting on null geodesics drive a secular growth of the positional elements. As an application of our results we examine the evolution of mean orbital elements in the semiclassical theory of quantum gravitational optics and show that the averaged correction terms are within the range of the uncertainty principle.

  2. Advances in corneal topography measurements with conical null-screens

    NASA Astrophysics Data System (ADS)

    Campos-García, Manuel; Cossio-Guerrero, Cesar; Huerta-Carranza, Oliver; Moreno-Oliva, Víctor I.

    2015-09-01

    In this work we report the design of a null-screen for corneal topography. To avoid the difficulties in the alignment of the test system due to the face contour (eyebrows, nose, or eyelids), we design a conical null-screen with a novel radial points distribution drawn on it in such a way that its image, which is formed by reflection on the test surface, becomes an exact array of circular spots if the surface is perfect. Additionally, an algorithm to compute the sagittal and meridional radii of curvature for the corneal surface is presented. The sagittal radius is obtained from the surface normal, and the meridional radius is calculated from a function fitted to the derivative of the sagittal curvature by using the surfacenormals raw data. Experimental results for the testing a calibration spherical surface are shown. Also, we perform some corneal topography measurements.

  3. Holographic proof of the quantum null energy condition

    NASA Astrophysics Data System (ADS)

    Koeller, Jason; Leichenauer, Stefan

    2016-07-01

    We use holography to prove the quantum null energy condition (QNEC) at leading order in large N for CFTs and relevant deformations of CFTs in Minkowski space which have Einstein gravity duals. Given any codimension-two surface Σ which is locally stationary under a null deformation in the direction k at the point p , the QNEC is a lower bound on the energy-momentum tensor at p in terms of the second variation of the entropy to one side of Σ : ⟨Tk k⟩≥S''/2 π √{h } . In a CFT, conformal transformations of this inequality give results which apply when Σ is not locally stationary. The QNEC was proven previously for free theories, and taken together with our result this provides strong evidence that the QNEC is a true statement about quantum field theory in general.

  4. A phenotypic null hypothesis for the genetics of personality.

    PubMed

    Turkheimer, Eric; Pettersson, Erik; Horn, Erin E

    2014-01-01

    We review the genetically informed literature on the genetics of personality. Over the past century, quantitative genetic studies, using identical and fraternal twins, have demonstrated that differences in human personality are substantially heritable. We focus on more contemporary questions to which that basic observation has led. We examine whether differences in the heritability of personality are replicable across different traits, samples, and studies; how the heritability of personality relates to its reliability; and how behavior genetics can be employed in studies of validity, and we discuss the stability of personality in genetic and environmental variance. The appropriate null hypothesis in behavior genetics is not that genetic or environmental influence on personality is zero. Instead, we offer a phenotypic null hypothesis, which states that genetic variance is not an independent mechanism of individual differences in personality but rather a reflection of processes that are best conceptualized at the phenotypic level. PMID:24050184

  5. Higher-dimensional evolving wormholes satisfying the null energy condition

    NASA Astrophysics Data System (ADS)

    Zangeneh, Mahdi Kord; Lobo, Francisco S. N.; Riazi, Nematollah

    2014-07-01

    In this work, we consider the possibility of expanding wormholes in higher dimensions, which is an important ingredient of modern theories of fundamental physics. An important motivation is that nontrivial topological objects such as microscopic wormholes may have been enlarged to macroscopic sizes in an expanding inflationary cosmological background. Since the Ricci scalar is only a function of time in standard cosmological models, we use this property as a simplifying assumption. More specifically, we consider a particular class of wormhole solutions corresponding to the choice of a spatially homogeneous Ricci scalar. The possibility of obtaining solutions with normal and exotic matter is explored and we find a variety of solutions including those in four dimensions that satisfy the null energy condition in specific time intervals. In particular, for five dimensions, we find solutions that satisfy the null energy condition throughout the respective evolution.

  6. Axon and muscle spindle hyperplasia in the myostatin null mouse

    PubMed Central

    Elashry, Mohamed I; Otto, Anthony; Matsakas, Antonios; El-Morsy, Salah E; Jones, Lisa; Anderson, Bethan; Patel, Ketan

    2011-01-01

    Germline deletion of the myostatin gene results in hyperplasia and hypertrophy of the tension-generating (extrafusal) fibres in skeletal muscle. As this gene is expressed predominantly in myogenic tissues it offers an excellent model with which to investigate the quantitative relationship between muscle and axonal development. Here we show that skeletal muscle hyperplasia in myostatin null mouse is accompanied by an increase in nerve fibres in major nerves of both the fore- and hindlimbs. We show that axons within these nerves undergo hypertrophy. Furthermore, we provide evidence that the age-related neural atrophic process is delayed in the absence of myostatin. Finally, we show that skeletal muscle hyperplasia in the myostatin null mouse is accompanied by an increase in the number of muscle spindles (also called stretch receptors or proprioceptors). However, our work demonstrates that the mechanisms regulating intrafusal fibre hyperplasia and hypertrophy differ from those that control the aetiology of extrafusal fibres. PMID:21208206

  7. Quantization of black hole entropy from unstable circular null geodesics

    NASA Astrophysics Data System (ADS)

    Wei, Shao-Wen; Liu, Yu-Xiao; Fu, Chun-E.

    2016-04-01

    The quasinormal mode frequencies can be understood from the massless particles trapped at the unstable circular null geodesics and slowly leaking out to infinity. Based on this viewpoint, in this paper, we semiclassically construct the entropy spectrum of the static and stationary black holes from the null geodesics. The result shows that the spacing of the entropy spectrum only depends on the property of the black hole in the eikonal limit. Moreover, for a black hole far from the extremal case, the spacing is found to be smaller than 2πħ for any dimension, which is very different from the result of the previous work by using the usual quasinormal mode frequencies.

  8. Exact Null Controllability of a Nonlinear Thermoelastic Contact Problem

    SciTech Connect

    Sivergina, Irina F. Polis, Michael P.

    2005-01-15

    We study the controllability properties of a nonlinear parabolic system that models the temperature evolution of a one-dimensional thermoelastic rod that may come into contact with a rigid obstacle. Basically the system dynamics is described by a one-dimensional nonlocal heat equation with a nonlinear and nonlocal boundary condition of Newmann type.We focus on the control problem and treat the case when the control is distributed over the whole space domain. In this case the system is proved to be exactly null controllable provided the parameters of the system are smooth.The proof is based on changing the control variable and using Aubin's Compactness Lemma to obtain an invariant set for the linearized controllability map. Then, by proving that the found solution is sufficiently smooth, we get the null controllability for the original system.

  9. Uniqueness of Kerr space-time near null infinity

    SciTech Connect

    Wu Xiaoning; Bai Shan

    2008-12-15

    We reexpress the Kerr metric in standard Bondi-Sachs coordinates near null infinity I{sup +}. Using the uniqueness result of the characteristic initial value problem, we prove the Kerr metric is the only asymptotically flat, stationary, axially symmetric, type-D solution of the vacuum Einstein equation. The Taylor series of Kerr space-time is expressed in terms of Bondi-Sachs coordinates, and the Newman-Penrose constants have been calculated.

  10. Nulling Hall-Effect Current-Measuring Circuit

    NASA Technical Reports Server (NTRS)

    Sullender, Craig C.; Vazquez, Juan M.; Berru, Robert I.

    1993-01-01

    Circuit measures electrical current via combination of Hall-effect-sensing and magnetic-field-nulling techniques. Known current generated by feedback circuit adjusted until it causes cancellation or near cancellation of magnetic field produced in toroidal ferrite core by current measured. Remaining magnetic field measured by Hall-effect sensor. Circuit puts out analog signal and digital signal proportional to current measured. Accuracy of measurement does not depend on linearity of sensing components.

  11. Nrf2 Deficiency Improves Glucose Tolerance in Mice Fed a High-Fat Diet

    PubMed Central

    Zhang, Yu-Kun Jennifer; Wu, Kai Connie; Liu, Jie; Klaassen, Curtis D.

    2012-01-01

    Nrf2, a master regulator of intracellular redox homeostasis, is indicated to participate in fatty acid metabolism in liver. However, its role in diet-induced obesity remains controversial. In the current study, genetically engineered Nrf2-null, wild-type (WT), and Nrf2-activated, Keap1-knockdown (K1-KD) mice were fed either a control or a high-fat western diet (HFD) for 12 weeks. The results indicate that the absence or enhancement of Nrf2 activity did not prevent diet-induced obesity, had limited effects on lipid metabolism, but affected blood glucose homeostasis. Whereas the Nrf2-null mice were resistant to HFD-induced glucose intolerance, the Nrf2-activated K1-KD mice exhibited prolonged elevation of circulating glucose during a glucose tolerance test even on the control diet. Feeding a HFD did not activate the Nrf2 signaling pathway in mouse livers. Fibroblast growth factor 21 (Fgf21) is a liver-derived anti-diabetic hormone that exerts glucose- and lipid-lowering effects. Fgf21 mRNA and protein were both elevated in livers of Nrf2-null mice, and Fgf21 protein was lower in K1-KD mice than WT mice. The inverse correlation between Nrf2 activity and hepatic expression of Fgf21 might explain the improved glucose tolerance in Nrf2-null mice. Furthermore, a more oxidative cellular environment in Nrf2-null mice could affect insulin signaling in liver. For example, mRNA of insulin-like growth factor binding protein 1, a gene repressed by insulin in hepatocytes, was markedly elevated in livers of Nrf2-null mice. In conclusion, genetic alteration of Nrf2 does not prevent diet-induced obesity in mice, but deficiency of Nrf2 improves glucose homeostasis, possibly through its effects on Fgf21 and/or insulin signaling. PMID:23017736

  12. Metabolism and pharmacokinetics of the anti-tuberculosis drug ethionamide in a flavin-containing monooxygenase null mouse.

    PubMed

    Palmer, Amy L; Leykam, Virginia L; Larkin, Andrew; Krueger, Sharon K; Phillips, Ian R; Shephard, Elizabeth A; Williams, David E

    2012-01-01

    Multiple drug resistance (MDR) in Mycobacterium tuberculosis (mTB), the causative agent for tuberculosis (TB), has led to increased use of second-line drugs, including ethionamide (ETA). ETA is a prodrug bioactivated by mycobacterial and mammalian flavin-containing monooxygenases (FMOs). FMO2 is the major isoform in the lungs of most mammals, including primates. In humans a polymorphism exists in the expression of FMO2. FMO2.2 (truncated, inactive) protein is produced by the common allele, while the ancestral allele, encoding active FMO2.1, has been documented only in individuals of African and Hispanic origin, at an incidence of up to 50% and 7%, respectively. We hypothesized that FMO2 variability in TB-infected individuals would yield differences in concentrations and ratios of ETA prodrug and metabolites. In this study we assessed the impact of the FMO2 genetic polymorphism on the pharmacokinetics of ETA after administration of a single oral dose of ETA (125 mg/kg) to wild type and triple Fmo1/2/4-null mice, measuring levels of prodrug vs. metabolites in plasma collected from 0 to 3.5 h post-gavage. All mice metabolized ETA to ETA S-oxide (ETASO) and 2-ethyl-4-amidopyridine (ETAA). Wild type mice had higher plasma concentrations of metabolites than of parent compound (p = 0.001). In contrast, Fmo1/2/4-null mice had higher plasma concentrations of parent compound than of metabolites (p = 0.0001). Thus, the human FMO2 genotype could impact the therapeutic efficacy and/or toxicity of ETA. PMID:23580869

  13. Enterocolitis causes profound lymphoid depletion in endothelin receptor B- and endothelin 3-null mouse models of Hirschsprung-associated enterocolitis

    PubMed Central

    Frykman, Philip K.; Cheng, Zhi; Wang, Xiao; Dhall, Deepti

    2015-01-01

    Potentially life-threatening enterocolitis is the most frequent complication in children with colonic aganglionosis (Hirschsprung disease, HSCR), and little is known about the mechanisms leading to enterocolitis. Splenic lymphopenia has been reported in the Endothelin Receptor B (Ednrb)-null mouse model of HSCR that develops enterocolitis. In this study, we sought to identify molecular mechanisms underlying this immune phenotype. We employed the Ednrb−/− mouse, and the knockout of its ligand, Edn3 (Edn3−/−). The major finding is that enterocolitis in the Ednrb−/− and Edn3−/− mice lead to thymic involution, splenic lymphopenia, and suppression of B lymphopoiesis as a consequence of colonic aganglionosis, not an intrinsic Edn3-Ednrb signaling defect directly affecting the lymphoid organs. We showed that adoptive transfer of Ednrb−/− marrow repopulated the RAG2-null mice marrow, thymus and spleen without development of enterocolitis. We identified the glucocorticoid corticosterone, as a potential mediator of the immune phenotype. This previously unrecognized pattern of immune abnormalities in mouse is nearly identical to lymphoid depletion in neonatal sepsis during severe physiological stress, suggesting that the mouse model used here could be also used for sepsis studies. PMID:25487064

  14. Non-null annular subaperture stitching interferometry for aspheric test

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Liu, Dong; Shi, Tu; Yang, Yongying; Chong, Shiyao; Miao, Liang; Huang, Wei; Shen, Yibing; Bai, Jian

    2015-10-01

    A non-null annular subaperture stitching interferometry (NASSI), combining the subaperture stitching idea and non-null test method, is proposed for steep aspheric testing. Compared with standard annular subaperture stitching interferometry (ASSI), a partial null lens (PNL) is employed as an alternative to the transmission sphere, to generate different aspherical wavefronts as the references. The coverage subaperture number would thus be reduced greatly for the better performance of aspherical wavefronts in matching the local slope of aspheric surfaces. Instead of various mathematical stitching algorithms, a simultaneous reverse optimizing reconstruction (SROR) method based on system modeling and ray tracing is proposed for full aperture figure error reconstruction. All the subaperture measurements are simulated simultaneously with a multi-configuration model in a ray-tracing program, including the interferometric system modeling and subaperture misalignments modeling. With the multi-configuration model, full aperture figure error would be extracted in form of Zernike polynomials from subapertures wavefront data by the SROR method. This method concurrently accomplishes subaperture retrace error and misalignment correction, requiring neither complex mathematical algorithms nor subaperture overlaps. A numerical simulation exhibits the comparison of the performance of the NASSI and standard ASSI, which demonstrates the high accuracy of the NASSI in testing steep aspheric. Experimental results of NASSI are shown to be in good agreement with that of Zygo® VerifireTM Asphere interferometer.

  15. High-power, null-type, inverted pendulum thrust stand.

    PubMed

    Xu, Kunning G; Walker, Mitchell L R

    2009-05-01

    This article presents the theory and operation of a null-type, inverted pendulum thrust stand. The thrust stand design supports thrusters having a total mass up to 250 kg and measures thrust over a range of 1 mN to 5 N. The design uses a conventional inverted pendulum to increase sensitivity, coupled with a null-type feature to eliminate thrust alignment error due to deflection of thrust. The thrust stand position serves as the input to the null-circuit feedback control system and the output is the current to an electromagnetic actuator. Mechanical oscillations are actively damped with an electromagnetic damper. A closed-loop inclination system levels the stand while an active cooling system minimizes thermal effects. The thrust stand incorporates an in situ calibration rig. The thrust of a 3.4 kW Hall thruster is measured for thrust levels up to 230 mN. The uncertainty of the thrust measurements in this experiment is +/-0.6%, determined by examination of the hysteresis, drift of the zero offset and calibration slope variation. PMID:19485530

  16. Reverse optimization reconstruction method in non-null aspheric interferometry

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Liu, Dong; Shi, Tu; Yang, Yongying; Chong, Shiyao; Shen, Yibing; Bai, Jian

    2015-10-01

    Aspheric non-null test achieves more flexible measurements than the null test. However, the precision calibration for retrace error has always been difficult. A reverse optimization reconstruction (ROR) method is proposed for the retrace error calibration as well as the aspheric figure error extraction based on system modeling. An optimization function is set up with system model, in which the wavefront data from experiment is inserted as the optimization objective while the figure error under test in the model as the optimization variable. The optimization is executed by the reverse ray tracing in the system model until the test wavefront in the model is consistent with the one in experiment. At this point, the surface figure error in the model is considered to be consistent with the one in experiment. With the Zernike fitting, the aspheric surface figure error is then reconstructed in the form of Zernike polynomials. Numerical simulations verifying the high accuracy of the ROR method are presented with error considerations. A set of experiments are carried out to demonstrate the validity and repeatability of ROR method. Compared with the results of Zygo interferometer (null test), the measurement error by the ROR method achieves better than 1/10λ.

  17. Variational principle for gravity with null and non-null boundaries: a unified boundary counter-term

    NASA Astrophysics Data System (ADS)

    Parattu, Krishnamohan; Chakraborty, Sumanta; Padmanabhan, T.

    2016-03-01

    It is common knowledge that the Einstein-Hilbert action does not furnish a well-posed variational principle. The usual solution to this problem is to add an extra boundary term to the action, called a counter-term, so that the variational principle becomes well-posed. When the boundary is spacelike or timelike, the Gibbons-Hawking-York counter-term is the most widely used. For null boundaries, we had proposed a counter-term in a previous paper. In this paper, we extend the previous analysis and propose a counter-term that can be used to eliminate variations of the "off-the-surface" derivatives of the metric on any boundary, regardless of its spacelike, timelike or null nature.

  18. Chemical changes in DMP1-null murine bone & silica based pecvd coatings for titanium implant osseoapplications

    NASA Astrophysics Data System (ADS)

    Maginot, Megen

    In order to improve clinical outcomes in bone-implant systems, a thorough understanding of both local bone chemistry and implant surface chemistry is necessary. This study consists, therefore, of two main parts: one focused on determining the nature of the changes in bone chemistry in a DMP1-null transgenic disease model and the other on the development of amorphous silica-based coatings for potential use as titanium bone implant coatings. For the study of bone mineral in the DMP1 transgenic model, which is known to have low serum phosphate levels, transgenic DMP1-null and wild type mice were fed a high phosphate diet, sacrificed, and had their long bone harvested. This bone was characterized using SEM, FTIR, microCT and XANES and compared to DMP1-null and wild type control groups to assess the therapeutic effect of high Pi levels on the phenotype and the role of DMP1 in mineralization in vivo. Findings suggest that though the high phosphate diet results in restoring serum phosphate levels, it does not completely rescue the bone mineral phenotype at an ultrastructural level and implicates DMP1 in phosphate nucleation. Since plasma enhanced chemical vapor deposition (PECVD) silica like coatings have not previously been fabricated for use in oessoapplications, the second part of this study initially focused on the characterization of novel SiOx chemistries fabricated via a chemical vapor deposition process that were designed specifically to act as bioactive coatings with a loose, hydrogenated structure. These coatings were then investigated for their potential initial stage response to bone tissue through immersion in a simulated body fluid and through the culture of MC3T3 cells on the coating surfaces. Coating surfaces were characterized by SEM, FTIR, contact angle measurements, and XANES. Coating dissolution and ionic release were also investigated by ICP-OES. Findings suggest that some SiOx chemistries may form a bioactive coating while more highly substituted

  19. Tumor microvasculature with endothelial fenestrations in VHL null clear cell renal cell carcinomas as a potent target of anti-angiogenic therapy.

    PubMed

    Yamasaki, Toshinari; Kamba, Tomomi; Kanno, Toru; Inoue, Takahiro; Shibasaki, Noboru; Arakaki, Ryuichiro; Yamada, Tomomi; Kondo, Keiichi; Kamoto, Toshiyuki; Nishiyama, Hiroyuki; Ogawa, Osamu; Nakamura, Eijiro

    2012-11-01

    Vascular endothelial growth factor (VEGF)-targeted therapies show significant antitumor effects for advanced clear cell renal cell carcinomas (CC-RCCs). Previous studies using VEGF inhibitors in mice models revealed that VEGF-dependent capillaries were characterized by the existence of endothelial fenestrations (EFs). In this study, we revealed that capillaries with abundant EFs did exist, particularly in CC-RCCs harboring VHL mutation. This finding was recapitulated in mice xenograft models, in which tumors from VHL null cells showed more abundant EFs compared to those from VHL wild-type cells. Importantly, treatment with bevacizumab resulted in a significant decrease of tumor size established from VHL null cells. Additionally, a significant reduction of EFs and microvessel density was observed in VHL null tumors. Indeed, xenograft from 786-O/mock (pRC3) cells developed four times more abundant EFs than that from 786-O/VHL (WT8). However, introduction of the constitutively active form of hypoxia-inducible factor (HIF)-2α to WT8 cells failed to either augment the number of EFs or restore the sensitivity to bevacizumab in mice xenograft, irrespective of the equivalent production of VEGF to 786-O/mock cells. These results indicated that HIF-2α independent factors also play significant roles in the development of abundant EFs. In fact, several angiogenesis-related genes including CCL2 were upregulated in 786-O cells in a HIF-2α independent manner. Treatment with CCL2 neutralizing antibody caused significant reduction of capillaries with EFs in 786-O xenograft, indicating that they were also sensitive to CCL2 inhibition as well as VEGF. Collectively, these results strongly indicated that capillaries with distinctive phenotype developed in VHL null CC-RCCs are potent targets for anti-angiogenic therapy. PMID:22931246

  20. A functional null mutation of SCN1B in a patient with Dravet syndrome.

    PubMed

    Patino, Gustavo A; Claes, Lieve R F; Lopez-Santiago, Luis F; Slat, Emily A; Dondeti, Raja S R; Chen, Chunling; O'Malley, Heather A; Gray, Charles B B; Miyazaki, Haruko; Nukina, Nobuyuki; Oyama, Fumitaka; De Jonghe, Peter; Isom, Lori L

    2009-08-26

    Dravet syndrome (also called severe myoclonic epilepsy of infancy) is one of the most severe forms of childhood epilepsy. Most patients have heterozygous mutations in SCN1A, encoding voltage-gated sodium channel Na(v)1.1 alpha subunits. Sodium channels are modulated by beta1 subunits, encoded by SCN1B, a gene also linked to epilepsy. Here we report the first patient with Dravet syndrome associated with a recessive mutation in SCN1B (p.R125C). Biochemical characterization of p.R125C in a heterologous system demonstrated little to no cell surface expression despite normal total cellular expression. This occurred regardless of coexpression of Na(v)1.1 alpha subunits. Because the patient was homozygous for the mutation, these data suggest a functional SCN1B null phenotype. To understand the consequences of the lack of beta1 cell surface expression in vivo, hippocampal slice recordings were performed in Scn1b(-/-) versus Scn1b(+/+) mice. Scn1b(-/-) CA3 neurons fired evoked action potentials with a significantly higher peak voltage and significantly greater amplitude compared with wild type. However, in contrast to the Scn1a(+/-) model of Dravet syndrome, we found no measurable differences in sodium current density in acutely dissociated CA3 hippocampal neurons. Whereas Scn1b(-/-) mice seize spontaneously, the seizure susceptibility of Scn1b(+/-) mice was similar to wild type, suggesting that, like the parents of this patient, one functional SCN1B allele is sufficient for normal control of electrical excitability. We conclude that SCN1B p.R125C is an autosomal recessive cause of Dravet syndrome through functional gene inactivation. PMID:19710327

  1. A functional null mutation of SCN1B in a patient with Dravet Syndrome

    PubMed Central

    Patino, Gustavo A.; Claes, Lieve R.F.; Lopez-Santiago, Luis; Slat, Emily A.; Dondeti, Raja S. R.; Chen, Chunling; O'Malley, Heather A.; Gray, Charles B.B.; Miyazaki, Haruko; Nukina, Nobuyuki; Oyama, Fumitaka; Jonghe, Peter De; Isom, Lori L.

    2009-01-01

    Dravet syndrome (also called Severe Myoclonic Epilepsy of Infancy) is one of the most severe forms of childhood epilepsy. Most patients have heterozygous mutations in SCN1A, encoding voltage-gated sodium channel Nav1.1 α subunits. Sodium channels are modulated by β1 subunits, encoded by SCN1B, a gene also linked to epilepsy. Here we report the first patient with Dravet Syndrome associated with a recessive mutation in SCN1B (p.R125C). Biochemical characterization of p.R125C in a heterologous system demonstrated little to no cell surface expression despite normal total cellular expression. This occurred regardless of co-expression of Nav1.1 α subunits. Because the patient was homozygous for the mutation, these data suggest a functional SCN1B null phenotype. To understand the consequences of the lack of β1 cell surface expression in vivo, hippocampal slice recordings were performed in Scn1b−/− vs. Scn1b+/+ mice. Scn1b−/− CA3 neurons fired evoked action potentials with a significantly higher peak voltage and significantly greater amplitude compared to wildtype. However, in contrast to the Scn1a+/− model of Dravet syndrome, we found no measurable differences in sodium current density in acutely dissociated CA3 hippocampal neurons. While Scn1b−/− mice seize spontaneously, the seizure susceptibility of Scn1b+/− mice was similar to wildtype, suggesting that, like the parents of this patient, one functional SCN1B allele is sufficient for normal control of electrical excitability. We conclude that SCN1B p.R125C is an autosomal recessive cause of Dravet syndrome through functional gene inactivation. PMID:19710327

  2. Null controllable region of delta operator systems subject to actuator saturation

    NASA Astrophysics Data System (ADS)

    Yang, Hongjiu; Yan, Ce; Xia, Yuanqing; Zhang, Jinhui

    2016-07-01

    In this paper, we give exact description of null controllable regions for delta operator systems subject to actuator saturation. The null controllable region is in terms of a set of extremal trajectories of anti-stable subsystems. For the delta operator system with real eigenvalues or complex eigenvalues, the description is simplified to an explicit formula which is used to characterise the boundary of a null controllable region. The relations of null controllable regions are shown separately for continuous-time systems, discrete-time systems and delta operator systems. Two numerical examples are given to illustrate the effectiveness of the proposed techniques on null controllable regions.

  3. Glycerol replacement corrects defective skin hydration, elasticity, and barrier function in aquaporin-3-deficient mice.

    PubMed

    Hara, Mariko; Verkman, A S

    2003-06-10

    Mice deficient in the epidermal water/glycerol transporter aquaporin-3 (AQP3) have reduced stratum corneum (SC) hydration and skin elasticity, and impaired barrier recovery after SC removal. SC glycerol content is reduced 3-fold in AQP3 null mice, whereas SC structure, protein/lipid composition, and ion/osmolyte content are not changed. We show here that glycerol replacement corrects each of the defects in AQP3 null mice. SC water content, measured by skin conductance and 3H2O accumulation, was 3-fold lower in AQP3 null vs. wild-type mice, but became similar after topical or systemic administration of glycerol in quantities that normalized SC glycerol content. SC water content was not corrected by glycerol-like osmolytes such as xylitol, erythritol, and propanediol. Orally administered glycerol fully corrected the reduced skin elasticity in AQP3 null mice as measured by the kinetics of skin displacement after suction, and the delayed barrier recovery as measured by transepidermal water loss after tape-stripping. Analysis of [14C]glycerol kinetics indicated reduced blood-to-SC transport of glycerol in AQP3 null mice, resulting in slowed lipid biosynthesis. These data provide functional evidence for a physiological role of glycerol transport by an aquaglyceroporin, and indicate that glycerol is a major determinant of SC water retention, and mechanical and biosynthetic functions. Our findings establish a scientific basis for the >200-yr-old empirical practice of including glycerol in cosmetic and medicinal skin formulations. PMID:12771381

  4. Abnormal regulation of TSG101 in mice with spongiform neurodegeneration

    PubMed Central

    Jiao, Jian; Sun, Kaihua; Walker, Will P.; Bagher, Pooneh; Cota, Christina D.; Gunn, Teresa M.

    2009-01-01

    Summary Spongiform neurodegeneration is characterized by the appearance of vacuoles throughout the central nervous system. It has many potential causes, but the underlying cellular mechanisms are not well understood. Mice lacking the E3 ubiquitin ligase Mahogunin Ring Finger-1 (MGRN1) develop age-dependent spongiform encephalopathy. We identified an interaction between a “PSAP” motif in MGRN1 and the ubiquitin E2 variant (UEV) domain of TSG101, a component of the endosomal sorting complex required for transport I (ESCRT-I), and demonstrate that MGRN1 multimonoubiquitinates TSG101. We examined the in vivo consequences of loss of MGRN1 on TSG101 expression and function in the mouse brain. The pattern of TSG101 ubiquitination differed in the brains of wild-type mice and Mgrn1 null mutant mice: at 1 month of age, null mutant mice had less ubiquitinated TSG101, while in adults, mutant mice had more ubiquitinated, insoluble TSG101 than wild-type mice. There was an associated increase in epidermal growth factor receptor (EGFR) levels in mutant brains. These results suggest that loss of MGRN1 promotes ubiquitination of TSG101 by other E3s and may prevent its disassociation from endosomal membranes or cause it to form insoluble aggregates. Our data implicate loss of normal TSG101 function in endo-lysosomal trafficking in the pathogenesis of spongiform neurodegeneration in Mgrn1 null mutant mice. PMID:19703557

  5. Broadband Achromatic Phase Shifter for a Nulling Interferometer

    NASA Technical Reports Server (NTRS)

    Bolcar, Matthew R.; Lyon, Richard G.

    2011-01-01

    Nulling interferometry is a technique for imaging exoplanets in which light from the parent star is suppressed using destructive interference. Light from the star is divided into two beams and a phase shift of radians is introduced into one of the beams. When the beams are recombined, they destructively interfere to produce a deep null. For monochromatic light, this is implemented by introducing an optical path difference (OPD) between the two beams equal to lambda/2, where lambda is the wavelength of the light. For broadband light, however, a different phase shift will be introduced at each wavelength and the two beams will not effectively null when recombined. Various techniques have been devised to introduce an achromatic phase shift a phase shift that is uniform across a particular bandwidth. One popular technique is to use a series of dispersive elements to introduce a wavelength-dependent optical path in one or both of the arms of the interferometer. By intelligently choosing the number, material and thickness of a series of glass plates, a nearly uniform, arbitrary phase shift can be introduced between two arms of an interferometer. There are several constraints that make choosing the number, type, and thickness of materials a difficult problem, such as the size of the bandwidth to be nulled. Several solutions have been found for bandwidths on the order of 20 to 30 percent (Delta(lambda)/lambda(sub c)) in the mid-infrared region. However, uniform phase shifts over a larger bandwidth in the visible regime between 480 to 960 nm (67 percent) remain difficult to obtain at the tolerances necessary for exoplanet detection. A configuration of 10 dispersive glass plates was developed to be used as an achromatic phase shifter in nulling interferometry. Five glass plates were placed in each arm of the interferometer and an additional vacuum distance was also included in the second arm of the interferometer. This configuration creates a phase shift of pi radians with

  6. Progranulin null mutations in both sporadic and familial frontotemporal dementia.

    PubMed

    Le Ber, Isabelle; van der Zee, Julie; Hannequin, Didier; Gijselinck, Ilse; Campion, Dominique; Puel, Michèle; Laquerrière, Annie; De Pooter, Tim; Camuzat, Agnès; Van den Broeck, Marleen; Dubois, Bruno; Sellal, François; Lacomblez, Lucette; Vercelletto, Martine; Thomas-Antérion, Catherine; Michel, Bernard-François; Golfier, Véronique; Didic, Mira; Salachas, François; Duyckaerts, Charles; Cruts, Marc; Verpillat, Patrice; Van Broeckhoven, Christine; Brice, Alexis

    2007-09-01

    Frontotemporal dementia (FTD) is the second most frequent type of neurodegenerative dementias. Mutations in the progranulin gene (GRN, PGRN) were recently identified in FTDU-17, an FTD subtype characterized by ubiquitin-immunoreactive inclusions and linkage to chromosome 17q21. We looked for PGRN mutations in a large series of 210 FTD patients (52 familial, 158 sporadic) to accurately evaluate the frequency of PGRN mutations in both sporadic and familial FTD, and FTD with associated motoneuron disease (FTD-MND), as well as to study the clinical phenotype of patients with a PGRN mutation. We identified nine novel PGRN null mutations in 10 index patients. The relative frequency of PGRN null mutations in FTD was 4.8% (10/210) and 12.8% (5/39) in pure familial forms. Interestingly, 5/158 (3.2%) apparently sporadic FTD patients carried a PGRN mutation, suggesting the possibility of de novo mutations or incomplete penetrance. In contrast, none of the 43 patients with FTD-MND had PGRN mutations, supporting that FTDU-17 and FTD-MND are genetically distinct. The clinical phenotype of PGRN mutation carriers was particular because of the wide range in onset age and the frequent occurrence of early apraxia (50%), visual hallucinations (30%), and parkinsonism (30%) during the course of the disease. This study supports that PGRN null mutations represent a more frequent cause of FTD than MAPT mutations (4.8% vs. 2.9%) but are not responsible for FTD-MND. It also demonstrates that half of the patients with a PGRN mutation in our series had no apparent family history of dementia. Taking this into account, genetic testing should be now considered more systematically, even in patients without obvious familial history of FTD. PMID:17436289

  7. Vacuum Nuller Testbed Performance, Characterization and Null Control

    NASA Technical Reports Server (NTRS)

    Lyon, R. G.; Clampin, M.; Petrone, P.; Mallik, U.; Madison, T.; Bolcar, M.; Noecker, C.; Kendrick, S.; Helmbrecht, M. A.

    2011-01-01

    The Visible Nulling Coronagraph (VNC) can detect and characterize exoplanets with filled, segmented and sparse aperture telescopes, thereby spanning the choice of future internal coronagraph exoplanet missions. NASA/Goddard Space Flight Center (GSFC) has developed a Vacuum Nuller Testbed (VNT) to advance this approach, and assess and advance technologies needed to realize a VNC as a flight instrument. The VNT is an ultra-stable testbed operating at 15 Hz in vacuum. It consists of a MachZehnder nulling interferometer; modified with a "W" configuration to accommodate a hexpacked MEMS based deformable mirror (DM), coherent fiber bundle and achromatic phase shifters. The 2-output channels are imaged with a vacuum photon counting camera and conventional camera. Error-sensing and feedback to DM and delay line with control algorithms are implemented in a real-time architecture. The inherent advantage of the VNC is that it is its own interferometer and directly controls its errors by exploiting images from bright and dark channels simultaneously. Conservation of energy requires the sum total of the photon counts be conserved independent of the VNC state. Thus sensing and control bandwidth is limited by the target stars throughput, with the net effect that the higher bandwidth offloads stressing stability tolerances within the telescope. We report our recent progress with the VNT towards achieving an incremental sequence of contrast milestones of 10(exp 8) , 10(exp 9) and 10(exp 10) respectively at inner working angles approaching 2A/D. Discussed will be the optics, lab results, technologies, and null control. Shown will be evidence that the milestones have been achieved.

  8. FAK mediates a compensatory survival signal parallel to PI3K-AKT in PTEN-null T-ALL cells.

    PubMed

    You, Dewen; Xin, Junping; Volk, Andrew; Wei, Wei; Schmidt, Rachel; Scurti, Gina; Nand, Sucha; Breuer, Eun-Kyoung; Kuo, Paul C; Breslin, Peter; Kini, Ameet R; Nishimura, Michael I; Zeleznik-Le, Nancy J; Zhang, Jiwang

    2015-03-31

    Mutations and inactivation of phosphatase and tensin homolog deleted from chromosome 10 (PTEN) are observed in 15%-25% of cases of human T cell acute lymphoblastic leukemia (T-ALL). Pten deletion induces myeloproliferative disorders (MPDs), acute myeloid leukemia (AML), and/or T-ALL in mice. Previous studies attributed Pten-loss-related hematopoietic defects and leukemogenesis to excessive activation of phosphatidylinositol 3-kinase (PI3K)/AKT/mTOR signaling. Although inhibition of this signal dramatically suppresses the growth of PTEN-null T-ALL cells in vitro, treatment with inhibitors of this pathway does not cause a complete remission in vivo. Here, we report that focal adhesion kinase (Fak), a protein substrate of Pten, also contributes to T-ALL development in Pten-null mice. Inactivation of the FAK signaling pathway by either genetic or pharmacologic methods significantly sensitizes both murine and human PTEN-null T-ALL cells to PI3K/AKT/mTOR inhibition when cultured in vitro on feeder layer cells or a matrix and in vivo. PMID:25801032

  9. Null controllability in a fluid-solid structure model

    NASA Astrophysics Data System (ADS)

    Raymond, J.-P.; Vanninathan, M.

    We consider a system coupling the Stokes equations in a two-dimensional domain with a structure equation which is a system of ordinary differential equations corresponding to a finite dimensional approximation of equations modeling deformations of an elastic body or vibrations of a rigid body. For that system we establish a null controllability result for localized distributed controls acting only in the fluid equations and there is no control in the solid part. This controllability result follows from a Carleman inequality that we prove for the adjoint system.

  10. Optical fiber null coupler sensor for damage detection using ultrasonic

    NASA Astrophysics Data System (ADS)

    Xuan, HaiFeng; Liao, Yanbiao; Zhang, Ming; Lai, Shu R.

    2005-02-01

    A novel optical fiber null coupler (OFNC) sensor based on acousto-optic interaction is developed, which can be used in the structure health monitoring of the medical materials. The OFNC sensors can be response to 10MHz supersonic wave, and their signal-to noise ratio are higher then Piezo Ceramic Transducers(PZT). A kind of Perspex with a 1mm hole is employed as the sample, where the OFNC sensor is glued on, and the reflected signal of ultrasonic wave by the hole is detected .

  11. Altered behavioral and metabolic circadian rhythms in mice with disrupted NAD+ oscillation

    PubMed Central

    Sahar, Saurabh; Nin, Veronica; Barbosa, Maria Thereza; Chini, Eduardo Nunes; Sassone-Corsi, Paolo

    2011-01-01

    The Intracellular levels of nicotinamide adenine dinucleotide (NAD+) are rhythmic and controlled by the circadian clock. However, whether NAD+ oscillation in turn contributes to circadian physiology is not fully understood. To address this question we analyzed mice mutated for the NAD+ hydrolase CD38. We found that rhythmicity of NAD+ was altered in the CD38-deficient mice. The high, chronic levels of NAD+ results in several anomalies in circadian behavior and metabolism. CD38-null mice display a shortened period length of locomotor activity and alteration in the rest-activity rhythm. Several clock genes and, interestingly, genes involved in amino acid metabolism were deregulated in CD38-null livers. Metabolomic analysis identified alterations in the circadian levels of several amino acids, specifically tryptophan levels were reduced in the CD38-null mice at a circadian time paralleling with elevated NAD+ levels. Thus, CD38 contributes to behavioral and metabolic circadian rhythms and altered NAD+ levels influence the circadian clock. PMID:21937766

  12. Personalized chemotherapy profiling using cancer cell lines from selectable mice

    PubMed Central

    Kamiyama, Hirohiko; Rauenzahn, Sherri; Shim, Joong Sup; Karikari, Collins A.; Feldmann, Georg; Hua, Li; Kamiyama, Mihoko; Schuler, F. William; Lin, Ming-Tseh; Beaty, Robert M.; Karanam, Balasubramanyam; Liang, Hong; Mullendore, Michael E.; Mo, Guanglan; Hidalgo, Manuel; Jaffee, Elizabeth; Hruban, Ralph H.; Jinnah, H. A.; Roden, Richard B. S.; Jimeno, Antonio; Liu, Jun O.; Maitra, Anirban; Eshleman, James R.

    2013-01-01

    Purpose High-throughput chemosensitivity testing of low-passage cancer cell lines can be used to prioritize agents for personalized chemotherapy. However, generating cell lines from primary cancers is difficult, because contaminating stromal cells overgrow the malignant cells. Experimental Design We produced a series of hypoxanthine phosphoribosyl transferase (hprt)-null immunodeficient mice. During growth of human cancers in these mice, hprt-null murine stromal cells replace their human counterparts. Results Pancreatic and ovarian cancers explanted from these mice were grown in selection media to produce pure human cancer cell lines. We screened one cell line with a 3,131-drug panel and identified seventy-seven FDA approved drugs with activity, including two novel drugs to which the cell line was uniquely sensitive. Xenografts of this carcinoma were selectively responsive to both drugs. Conclusion Chemotherapy can be personalized using patient-specific cell lines derived in biochemically selectable mice. PMID:23340293

  13. Toxicogenomic profiling of perfluorononanoic acid in wild-type and PPARa-null mice

    EPA Science Inventory

    Perfluorononanoic acid (PFNA) is a ubiquitous environmental contaminant and a developmental toxicant in laboratory animals. Like other perfluoroalkyl acids (PFAAs) such as perfluorooctane sulfonate (PFOA) and perfluoroalkyl acid (PFOS), PFNA is a known activator ofperoxisome prol...

  14. Secreted maltase-glucoamylase is upregulated in membrane maltase-glucoamylase null mice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The known mammalian brush-border glucohydrolases are membrane-bound, small intestine lumenal enzymes that digest dietary starches and sugars into monosaccharides for absorption. The phenotype of maltase-glucoamylase deficiency is not understood. To address this, we ablated membrane-bound maltase-gl...

  15. GENE PROFILING IN WILD-TYPE AND PPARα-NULL MICE EXPOSED TO PERFLUOROOCTANE SULFONATE

    EPA Science Inventory

    Perfluorooctane sulfonate (PFOS), a perfluoroalkyl acid (PFAA), is a persistent environmental contaminant found in the tissues of humans and wildlife. Over the last decade, health concerns have been raised, in part, because of the long half-life of PFOS and other PFAAs in humans,...

  16. Sc65-Null Mice Provide Evidence for a Novel Endoplasmic Reticulum Complex Regulating Collagen Lysyl Hydroxylation

    PubMed Central

    Weis, MaryAnn; Rai, Jyoti; Hudson, David M.; Dimori, Milena; Zimmerman, Sarah M.; Hogue, William R.; Swain, Frances L.; Burdine, Marie S.; Mackintosh, Samuel G.; Tackett, Alan J.; Suva, Larry J.; Eyre, David R.

    2016-01-01

    Collagen is a major component of the extracellular matrix and its integrity is essential for connective tissue and organ function. The importance of proteins involved in intracellular collagen post-translational modification, folding and transport was recently highlighted from studies on recessive forms of osteogenesis imperfecta (OI). Here we describe the critical role of SC65 (Synaptonemal Complex 65, P3H4), a leprecan-family member, as part of an endoplasmic reticulum (ER) complex with prolyl 3-hydroxylase 3. This complex affects the activity of lysyl-hydroxylase 1 potentially through interactions with the enzyme and/or cyclophilin B. Loss of Sc65 in the mouse results in instability of this complex, altered collagen lysine hydroxylation and cross-linking leading to connective tissue defects that include low bone mass and skin fragility. This is the first indication of a prolyl-hydroxylase complex in the ER controlling lysyl-hydroxylase activity during collagen synthesis. PMID:27119146

  17. COMPARING ENVIRONMENTALLY RELEVANT PCBS TO TCDD IN CYP1A2 NULL AND WILDTYPE MICE

    EPA Science Inventory


    The role of CYP1A2 on the interactions of TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin, dioxin), dioxin-like (DL) and non-dioxin-like (NDL) polychlorinated biphenyls (PCBs) was compared in multiple responses of different laboratory-defined mixtures, based on mass ratios found in...

  18. Evaluating Effects of Hypomorphic Thoc1 Alleles on Embryonic Development in Rb1 Null Mice.

    PubMed

    Chinnam, Meenalakshmi; Wang, Xiaoling; Zhang, Xiaojing; Goodrich, David W

    2016-06-01

    The Rb1 tumor suppressor protein is a molecular adaptor that physically links transcription factors like E2f with various proteins acting on DNA or RNA to repress gene expression. Loss of Rb1 liberates E2f to activate the expression of genes mediating resulting phenotypes. Most Rb1 binding proteins, including E2f, interact through carboxyl-terminal protein interaction domains, but genetic evidence suggests that an amino-terminal protein interaction domain is also important. One protein that binds Rb1 through the amino-terminal domain is encoded by Thoc1, a required component of the THO ribonucleoprotein complex important for RNA processing and transport. The physiological relevance of this interaction is unknown. Here we tested whether Thoc1 mediates effects of Rb1 loss on mouse embryonic development. We found that Thoc1 deficiency delays embryo death, and this delay correlates with reduced apoptosis in the brain. E2f protein levels are reduced in Rb1:Thoc1-deficient brain tissue. Expression of apoptotic regulatory genes regulated by E2f, like Apaf1 and Bak1, is also reduced. These observations suggest that Thoc1 is required to support increased expression of E2f and apoptotic regulatory genes that trigger apoptosis upon Rb1 loss. These findings implicate Rb1 in the regulation of the THO ribonucleoprotein complex. PMID:27001308

  19. Perilipin overexpression in mice protects against diet-induced obesity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Perilipin A is the most abundant phosphoprotein on adipocyte lipid droplets and is essential for lipid storage and lipolysis. Perilipin null mice exhibit diminished adipose tissue, elevated basal lipolysis, reduced catecholamine-stimulated lipolysis, and increased insulin resistance. To understand t...

  20. TIEG1 Null Mouse-Derived Osteoblasts Are Defective in Mineralization and in Support of Osteoclast Differentiation In Vitro

    PubMed Central

    Subramaniam, Malayannan; Gorny, Genevieve; Johnsen, Steven A.; Monroe, David G.; Evans, Glenda L.; Fraser, Daniel G.; Rickard, David J.; Rasmussen, Kay; van Deursen, Jan M. A.; Turner, Russell T.; Oursler, Merry Jo; Spelsberg, Thomas C.

    2005-01-01

    Transforming growth factor β-inducible early gene 1 (TIEG1) is a member of the Krüppel-like transcription factor family. To understand the physiological role of TIEG1, we generated TIEG−/− (null) mice and found that the TIEG−/− mice had increased osteoblast numbers with no increased bone formation parameters. However, when calvarial osteoblasts (OBs) were isolated from neonatal TIEG−/− and TIEG+/+ mice and cultured in vitro, the TIEG−/− cells displayed reduced expression of important OB differentiation markers. When the OBs were differentiated in vitro by treatment with bone morphogenic protein 2, the OBs from TIEG+/+ calvaria displayed several mineralized nodules in culture, whereas those from TIEG−/− mice showed no nodules. To characterize the OBs' ability to support osteoclast differentiation, the OBs from TIEG+/+ and TIEG−/− mice were cultured with marrow and spleen cells from TIEG+/+ mice. Significantly fewer osteoclasts