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Sample records for mice lacking ahr

  1. Dioxin-dependent and dioxin-independent gene batteries: comparison of liver and kidney in AHR-null mice.

    PubMed

    Boutros, Paul C; Bielefeld, Kirsten A; Pohjanvirta, Raimo; Harper, Patricia A

    2009-11-01

    The aryl hydrocarbon receptor (AHR) is a widely expressed ligand-dependent transcription factor that mediates cellular responses to dioxins and other planar aromatic hydrocarbons. Ahr-null mice are refractory to the toxic effects of dioxin exposure. Although some mechanistic aspects of AHR activity are well understood, the tissue specificity of AHR effects remains unclear, both during development and following administration of exogenous ligands. To address the latter issue, we defined and compared transcriptional responses to dioxin exposure in the liver and kidney of wild-type and Ahr-null adult C57BL/6J mice treated with either 2,3,7,8-tetrachlorodibenzo-p-dioxin or corn-oil vehicle. In both tissues, essentially all effects of dioxin on hepatic mRNA levels were mediated by the AHR. Although 297 genes were altered by dioxin exposure in the liver, only 17 were changed in the kidney, including a number of well-established AHR target genes. Ahr genotype had a large effect in both tissues, profoundly remodeling both the renal and hepatic transcriptomes. Surprisingly, a large number of genes were affected by Ahr genotype in both tissues, suggesting the presence of a basal AHR gene battery. Alterations of the renal transcriptome in Ahr-null animals were associated with perturbation of specific functional pathways and enrichment of specific DNA motifs. Our results demonstrate the importance of intertissue comparisons, highlight the basal role of the AHR in liver and kidney, and support a role in development or normal physiology.

  2. Tetrachlorodibenzo-p-dioxin exposure alters radial arm maze performance and hippocampal morphology in female AhR mice.

    PubMed

    Powers, B E; Lin, T-M; Vanka, A; Peterson, R E; Juraska, J M; Schantz, S L

    2005-02-01

    Perinatal exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has been reported to alter spatial learning in rats tested on a radial arm maze (RAM). TCDD is believed to exert most of its effects through binding to the aryl hydrocarbon receptor (AhR). To determine whether the AhR mediates TCDD-induced alterations in spatial learning, we tested male and female AhR-knockout (AhR-/-), heterozygous (AhR+/-) and wild-type (AhR+/+) mice on the RAM. AhR+/- male and female mice were time mated, and treated dams were dosed with 5 microg TCDD/kg body weight on day 13 of gestation. When offspring reached adulthood, male and female AhR+/+, AhR+/- and AhR-/- mice from TCDD-exposed and unexposed litters were tested on the eight-arm RAM. After testing, we examined hippocampal morphology as visualized by the Timm's silver sulfide stain. TCDD-exposed female AhR+/- mice made more errors than their respective controls on the RAM and exhibited a decrease in the size of the intra- and infrapyramidal mossy fiber (IIP-MF) field of the hippocampus. None of the other TCDD-exposed groups differed from their respective control groups with regard to maze performance or hippocampal morphology. The reduction of IIP-MF field indicates a possible morphological basis for the learning deficit that was observed in the female AhR+/- mice. It is hypothesized that the effect of TCDD exposure is AhR dependent and that TCDD may alter GABAergic activity in the hippocampus of female mice during development.

  3. Dioxin-Dependent and Dioxin-Independent Gene Batteries: Comparison of Liver and Kidney in AHR-Null Mice

    PubMed Central

    Boutros, Paul C.; Bielefeld, Kirsten A.; Pohjanvirta, Raimo; Harper, Patricia A.

    2009-01-01

    The aryl hydrocarbon receptor (AHR) is a widely expressed ligand-dependent transcription factor that mediates cellular responses to dioxins and other planar aromatic hydrocarbons. Ahr-null mice are refractory to the toxic effects of dioxin exposure. Although some mechanistic aspects of AHR activity are well understood, the tissue specificity of AHR effects remains unclear, both during development and following administration of exogenous ligands. To address the latter issue, we defined and compared transcriptional responses to dioxin exposure in the liver and kidney of wild-type and Ahr-null adult C57BL/6J mice treated with either 2,3,7,8-tetrachlorodibenzo-p-dioxin or corn-oil vehicle. In both tissues, essentially all effects of dioxin on hepatic mRNA levels were mediated by the AHR. Although 297 genes were altered by dioxin exposure in the liver, only 17 were changed in the kidney, including a number of well-established AHR target genes. Ahr genotype had a large effect in both tissues, profoundly remodeling both the renal and hepatic transcriptomes. Surprisingly, a large number of genes were affected by Ahr genotype in both tissues, suggesting the presence of a basal AHR gene battery. Alterations of the renal transcriptome in Ahr-null animals were associated with perturbation of specific functional pathways and enrichment of specific DNA motifs. Our results demonstrate the importance of intertissue comparisons, highlight the basal role of the AHR in liver and kidney, and support a role in development or normal physiology. PMID:19759094

  4. Deletion of Aryl Hydrocarbon Receptor AHR in Mice Leads to Subretinal Accumulation of Microglia and RPE Atrophy

    PubMed Central

    Kim, Soo-Young; Yang, Hyun-Jin; Chang, Yi-Sheng; Kim, Jung-Woong; Brooks, Matthew; Chew, Emily Y.; Wong, Wai T.; Fariss, Robert N.; Rachel, Rivka A.; Cogliati, Tiziana; Qian, Haohua; Swaroop, Anand

    2014-01-01

    Purpose. The aryl hydrocarbon receptor (AHR) is a ligand-activated nuclear receptor that regulates cellular response to environmental signals, including UV and blue wavelength light. This study was undertaken to elucidate AHR function in retinal homeostasis. Methods. RNA-seq data sets were examined for Ahr expression in the mouse retina and rod photoreceptors. The Ahr−/− mice were evaluated by fundus imaging, optical coherence tomography, histology, immunohistochemistry, and ERG. For light damage experiments, adult mice were exposed to 14,000 to 15,000 lux of diffuse white light for 2 hours. Results. In mouse retina, Ahr transcripts were upregulated during development, with continued increase in aging rod photoreceptors. Fundus examination of 3-month-old Ahr−/− mice revealed subretinal autofluorescent spots, which increased in number with age and following acute light exposure. Ahr−/− retina also showed subretinal microglia accumulation that correlated with autofluorescence changes, RPE abnormalities, and reactivity against immunoglobulin, complement factor H, and glial fibrillary acidic protein. Functionally, Ahr−/− mice displayed reduced ERG c-wave amplitudes. Conclusions. The Ahr−/− mice exhibited subretinal accumulation of microglia and focal RPE atrophy, phenotypes observed in AMD. Together with a recently published report on another Ahr−/− mouse model, our study suggests that AHR has a protective role in the retina as an environmental stress sensor. As such, its altered function may contribute to human AMD progression and provide a target for pharmacological intervention. PMID:25159211

  5. Uric acid stones in the urinary bladder of aryl hydrocarbon receptor (AhR) knockout mice

    PubMed Central

    Butler, Ryan; Inzunza, Jose; Suzuki, Hitoshi; Fujii-Kuriyama, Yoshiaki; Warner, Margaret; Gustafsson, Jan-Åke

    2012-01-01

    The aryl hydrocarbon receptor (AhR) knockout mice raised in the laboratory of Fujii-Kuriyama have been under investigation for several years because of the presence in their urinary bladder of large, yellowish stones. The stones are composed of uric acid and become apparent in the bladders as tiny stones when mice are 10 wk of age. By the time the mice are 6 mo of age, there are usually two or three stones with diameters of 3–4 mm. The urate concentration in the serum was normal but in the urine the concentration was 40–50 mg/dL, which is 10 times higher than that in the WT littermates. There were no apparent histological pathologies in the kidney or joints and the levels of enzymes involved in elimination of purines were normal. The source of the uric acid was therefore judged to be from degradation of nucleic acids due to a high turnover of cells in the bladder itself. The bladder was fibrotic and the luminal side of the bladder epithelium was filled with eosinophilic granules. There was loss of E-cadherin between some epithelial cells, with an enlarged submucosal area filled with immune cells and sometimes invading epithelial cells. We hypothesize that in the absence of AhR there is loss of detoxifying enzymes, which leads to accumulation of unconjugated cytotoxins and carcinogens in the bladder. The presence of bladder toxins may have led to the increased apoptosis and inflammation as well as invasion of epithelial cells in the bladders of older mice. PMID:22232670

  6. Uric acid stones in the urinary bladder of aryl hydrocarbon receptor (AhR) knockout mice.

    PubMed

    Butler, Ryan; Inzunza, Jose; Suzuki, Hitoshi; Fujii-Kuriyama, Yoshiaki; Warner, Margaret; Gustafsson, Jan-Åke

    2012-01-24

    The aryl hydrocarbon receptor (AhR) knockout mice raised in the laboratory of Fujii-Kuriyama have been under investigation for several years because of the presence in their urinary bladder of large, yellowish stones. The stones are composed of uric acid and become apparent in the bladders as tiny stones when mice are 10 wk of age. By the time the mice are 6 mo of age, there are usually two or three stones with diameters of 3-4 mm. The urate concentration in the serum was normal but in the urine the concentration was 40-50 mg/dL, which is 10 times higher than that in the WT littermates. There were no apparent histological pathologies in the kidney or joints and the levels of enzymes involved in elimination of purines were normal. The source of the uric acid was therefore judged to be from degradation of nucleic acids due to a high turnover of cells in the bladder itself. The bladder was fibrotic and the luminal side of the bladder epithelium was filled with eosinophilic granules. There was loss of E-cadherin between some epithelial cells, with an enlarged submucosal area filled with immune cells and sometimes invading epithelial cells. We hypothesize that in the absence of AhR there is loss of detoxifying enzymes, which leads to accumulation of unconjugated cytotoxins and carcinogens in the bladder. The presence of bladder toxins may have led to the increased apoptosis and inflammation as well as invasion of epithelial cells in the bladders of older mice.

  7. NK cells contribute to persistent airway inflammation and AHR during the later stage of RSV infection in mice.

    PubMed

    Long, Xiaoru; Xie, Jun; Zhao, Keting; Li, Wei; Tang, Wei; Chen, Sisi; Zang, Na; Ren, Luo; Deng, Yu; Xie, Xiaohong; Wang, Lijia; Fu, Zhou; Liu, Enmei

    2016-10-01

    RSV can lead to persistent airway inflammation and AHR and is intimately associated with childhood recurrent wheezing and asthma, but the underlying mechanisms remain unclear. There are high numbers of NK cells in the lung, which not only play important roles in the acute stage of RSV infection, but also are pivotal in regulating the pathogenesis of asthma. Therefore, in this study, we assumed that NK cells might contribute to persistent airway disease during the later stage of RSV infection. Mice were killed at serial time points after RSV infection to collect samples. Leukocytes in bronchoalveolar lavage fluid (BALF) were counted, lung histopathology was examined, and airway hyperresponsiveness (AHR) was measured by whole-body plethysmography. Cytokines were detected by ELISA, and NK cells were determined by flow cytometry. Rabbit anti-mouse asialo-GM-1 antibodies and resveratrol were used to deplete or suppress NK cells. Inflammatory cells in BALF, lung tissue damage and AHR were persistent for 60 days post-RSV infection. Type 2 cytokines and NK cells were significantly increased during the later stage of infection. When NK cells were decreased by the antibodies or resveratrol, type 2 cytokines, the persistent airway inflammation and AHR were all markedly reduced. NK cells can contribute to the RSV-associated persistent airway inflammation and AHR at least partially by promoting type 2 cytokines. Therefore, therapeutic targeting of NK cells may provide a novel approach to alleviating the recurrent wheezing subsequent to RSV infection.

  8. 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.

  9. Developmental Activation of the AHR Increases Effector CD4+ T Cells and Exacerbates Symptoms in Autoimmune Disease-Prone Gnaq+/− Mice

    PubMed Central

    Boule, Lisbeth A.; Burke, Catherine G.; Fenton, Bruce M.; Thevenet-Morrison, Kelly; Jusko, Todd A.; Lawrence, B. Paige

    2015-01-01

    Perinatal environmental exposures are potentially important contributors to the increase in autoimmune diseases. Yet, the mechanisms by which these exposures increase self-reactive immune responses later in life are poorly understood. Autoimmune diseases require CD4+ T cells for initiation, progression, and/or clinical symptoms; thus, developmental exposures that cause durable changes in CD4+ T cells may play a role. Early life activation of the aryl hydrocarbon receptor (AHR) causes persistent changes in the response of CD4+ T cells to infection later in life but whether CD4+ T cells are affected by developmental exposure in the context of an autoimmune disease is unknown. Gnaq+/− mice develop symptoms of autoimmune disease similar to those measured clinically, and therefore can be used to evaluate gene-environment interactions during development on disease progression. Herein, we examined the effect of AHR activation in utero and via lactation, or solely via lactation, on disease onset and severity in adult Gnaq+/− offspring. Developmental activation of the AHR-accelerated disease in Gnaq+/− mice, and this correlates with increases in effector CD4+ T-cell populations. Increased symptom onset and cellular changes due to early life AHR activation were more evident in female Gnaq+/− mice compared with males. These observations suggest that developmental AHR activation by pollutants, and other exogenous ligands, may increase the likelihood that genetically predisposed individuals will develop clinical symptoms of autoimmune disease later in life. PMID:26363170

  10. Perturbed hematopoiesis in mice lacking ATMIN

    PubMed Central

    Anjos-Afonso, Fernando; Loizou, Joanna I.; Bradburn, Amy; Kanu, Nnennaya; Purewal, Sukhveer; Da Costa, Clive; Behrens, Axel

    2016-01-01

    The ataxia telangiectasia mutated (ATM)-interacting protein ATMIN mediates noncanonical ATM signaling in response to oxidative and replicative stress conditions. Like ATM, ATMIN can function as a tumor suppressor in the hematopoietic system: deletion of Atmin under the control of CD19-Cre results in B-cell lymphomas in aging mice. ATM signaling is essential for lymphopoiesis and hematopoietic stem cell (HSC) function; however, little is known about the role of ATMIN in hematopoiesis. We thus sought to investigate whether the absence of ATMIN would affect primitive hematopoietic cells in an ATM-dependent or -independent manner. Apart from its role in B-cell development, we show that ATMIN has an ATM-independent function in the common myeloid progenitors (CMPs) by deletion of Atmin in the entire hematopoietic system using Vav-Cre. Despite the lack of lymphoma formation, ATMIN-deficient mice developed chronic leukopenia as a result of high levels of apoptosis in B cells and CMPs and induced a compensatory mechanism in which HSCs displayed enhanced cycling. Consequently, ATMIN-deficient HSCs showed impaired regeneration ability with the induction of the DNA oxidative stress response, especially when aged. ATMIN, therefore, has multiple roles in different cell types, and its absence results in perturbed hematopoiesis, especially during stress conditions and aging. PMID:27581360

  11. Developmental Activation of the AHR Increases Effector CD4+ T Cells and Exacerbates Symptoms in Autoimmune Disease-Prone Gnaq+/- Mice.

    PubMed

    Boule, Lisbeth A; Burke, Catherine G; Fenton, Bruce M; Thevenet-Morrison, Kelly; Jusko, Todd A; Lawrence, B Paige

    2015-12-01

    Perinatal environmental exposures are potentially important contributors to the increase in autoimmune diseases. Yet, the mechanisms by which these exposures increase self-reactive immune responses later in life are poorly understood. Autoimmune diseases require CD4(+) T cells for initiation, progression, and/or clinical symptoms; thus, developmental exposures that cause durable changes in CD4(+) T cells may play a role. Early life activation of the aryl hydrocarbon receptor (AHR) causes persistent changes in the response of CD4(+) T cells to infection later in life but whether CD4(+) T cells are affected by developmental exposure in the context of an autoimmune disease is unknown. Gnaq(+/-) mice develop symptoms of autoimmune disease similar to those measured clinically, and therefore can be used to evaluate gene-environment interactions during development on disease progression. Herein, we examined the effect of AHR activation in utero and via lactation, or solely via lactation, on disease onset and severity in adult Gnaq(+/-) offspring. Developmental activation of the AHR-accelerated disease in Gnaq(+/-) mice, and this correlates with increases in effector CD4(+) T-cell populations. Increased symptom onset and cellular changes due to early life AHR activation were more evident in female Gnaq(+/-) mice compared with males. These observations suggest that developmental AHR activation by pollutants, and other exogenous ligands, may increase the likelihood that genetically predisposed individuals will develop clinical symptoms of autoimmune disease later in life. © The Author 2015. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  12. In Utero and Lactational Exposure to PCBs in Mice: Adult Offspring Show Altered Learning and Memory Depending on Cyp1a2 and Ahr Genotypes

    PubMed Central

    Curran, Christine P.; Genter, Mary Beth; Patel, Krishna V.; Schaefer, Tori L.; Skelton, Matthew R.; Williams, Michael T.; Vorhees, Charles V.

    2011-01-01

    Background: Both coplanar and noncoplanar polychlorinated biphenyls (PCBs) exhibit neurotoxic effects in animal studies, but individual congeners do not always produce the same effects as PCB mixtures. Humans genetically have > 60-fold differences in hepatic cytochrome P450 1A2 (CYP1A2)-uninduced basal levels and > 12-fold variability in aryl hydrocarbon receptor (AHR)affinity; because CYP1A2 is known to sequester coplanar PCBs and because AHR ligands include coplanar PCBs, both genotypes can affect PCB response. Objectives: We aimed to develop a mouse paradigm with extremes in Cyp1a2 and Ahr genotypes to explore genetic susceptibility to PCB-induced developmental neurotoxicity using an environmentally relevant mixture of PCBs. Methods: We developed a mixture of eight PCBs to simulate human exposures based on their reported concentrations in human tissue, breast milk, and food supply. We previously characterized specific differences in PCB congener pharmacokinetics and toxicity, comparing high-affinity–AHR Cyp1a2 wild-type [Ahrb1_Cyp1a2(+/+)], poor-affinity–AHR Cyp1a2 wild-type [Ahrd_Cyp1a2(+/+)], and high-affinity–AHR Cyp1a2 knockout [Ahrb1_Cyp1a2(–/–)] mouse lines [Curran CP, Vorhees CV, Williams MT, Genter MB, Miller ML, Nebert DW. 2011. In utero and lactational exposure to a complex mixture of polychlorinated biphenyls: toxicity in pups dependent on the Cyp1a2 and Ahr genotypes. Toxicol Sci 119:189–208]. Dams received a mixture of three coplanar and five noncoplanar PCBs on gestational day 10.5 and postnatal day (PND) 5. In the present study we conducted behavioral phenotyping of exposed offspring at PND60, examining multiple measures of learning, memory, and other behaviors. Results: We observed the most significant deficits in response to PCB treatment in Ahrb1_Cyp1a2(–/–) mice, including impaired novel object recognition and increased failure rate in the Morris water maze. However, all PCB-treated genotypes showed significant differences on

  13. Effects of Developmental Activation of the AhR on CD4+ T-Cell Responses to Influenza Virus Infection in Adult Mice

    PubMed Central

    Boule, Lisbeth A.; Winans, Bethany

    2014-01-01

    Background: Epidemiological and animal studies indicate that maternal exposure to pollutants that bind the aryl hydrocarbon receptor (AhR) correlates with poorer ability to combat respiratory infection and lower antibody levels in the offspring. These observations point to an impact on CD4+ T cells. Yet, the consequence of developmental exposure to AhR ligands on the activation and differentiation of CD4+ T cells has not been directly examined. Objectives: Our goal was to determine whether maternal exposure to an AhR ligand directly alters CD4+ T cell differentiation and function later in life. Methods: C57BL/6 mice were exposed to a prototypical AhR ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), in utero and via suckling. We then measured CD4+ T-cell activation and differentiation into distinct effector populations in adult offspring that were infected with influenza A virus (IAV). Reciprocal adoptive transfers were used to define whether modifications in CD4+ T-cell responses resulted from direct effects of developmental TCDD exposure on CD4+ T cells. Results: Developmental exposure skewed CD4+ T-cell responses to IAV infection. We observed fewer virus-specific, activated CD4+ T cells and a reduced frequency of conventional CD4+ effector-cell subsets. However, there was an increase in regulatory CD4+ T cells. Direct effects of AhR activation on CD4+ T cells resulted in impaired differentiation into conventional effector subsets; this defect was transferred to mice that had not been developmentally exposed to TCDD. Conclusions: Maternal exposure to TCDD resulted in durable changes in the responsive capacity and differentiation of CD4+ T cells in adult C57BL/6 mice. Citation: Boule LA, Winans B, Lawrence BP. 2014. Effects of developmental activation of the AhR on CD4+ T-cell responses to influenza virus infection in adult mice. Environ Health Perspect 122:1201–1208; http://dx.doi.org/10.1289/ehp.1408110 PMID:25051576

  14. Hoxc13 mutant mice lack external hair.

    PubMed

    Godwin, A R; Capecchi, M R

    1998-01-01

    Hox genes are usually expressed temporally and spatially in a colinear manner with respect to their positions in the Hox complex. Consistent with the expected pattern for a paralogous group 13 member, early embryonic Hoxc13 expression is found in the nails and tail. Hoxc13 is also expressed in vibrissae, in the filiform papillae of the tongue, and in hair follicles throughout the body; a pattern that apparently violates spatial colinearity. Mice carrying mutant alleles of Hoxc13 have been generated by gene targeting. Homozygotes have defects in every region in which gene expression is seen. The most striking defect is brittle hair resulting in alopecia (hairless mice). One explanation for this novel role is that Hoxc13 has been recruited for a function common to hair, nail, and filiform papilla development.

  15. Parturition failure in mice lacking Mamld1.

    PubMed

    Miyado, Mami; Miyado, Kenji; Katsumi, Momori; Saito, Kazuki; Nakamura, Akihiro; Shihara, Daizou; Ogata, Tsutomu; Fukami, Maki

    2015-10-05

    In mice, the onset of parturition is triggered by a rapid decline in circulating progesterone. Progesterone withdrawal occurs as a result of functional luteolysis, which is characterized by an increase in the enzymatic activity of 20α-hydroxysteroid dehydrogenase (20α-HSD) in the corpus luteum and is mediated by the prostaglandin F2α (PGF2α) signaling. Here, we report that the genetic knockout (KO) of Mamld1, which encodes a putative non-DNA-binding regulator of testicular steroidogenesis, caused defective functional luteolysis and subsequent parturition failure and neonatal deaths. Progesterone receptor inhibition induced the onset of parturition in pregnant KO mice, and MAMLD1 regulated the expression of Akr1c18, the gene encoding 20α-HSD, in cultured cells. Ovaries of KO mice at late gestation were morphologically unremarkable; however, Akr1c18 expression was reduced and expression of its suppressor Stat5b was markedly increased. Several other genes including Prlr, Cyp19a1, Oxtr, and Lgals3 were also dysregulated in the KO ovaries, whereas PGF2α signaling genes remained unaffected. These results highlight the role of MAMLD1 in labour initiation. MAMLD1 likely participates in functional luteolysis by regulating Stat5b and other genes, independent of the PGF2α signaling pathway.

  16. Parturition failure in mice lacking Mamld1

    PubMed Central

    Miyado, Mami; Miyado, Kenji; Katsumi, Momori; Saito, Kazuki; Nakamura, Akihiro; Shihara, Daizou; Ogata, Tsutomu; Fukami, Maki

    2015-01-01

    In mice, the onset of parturition is triggered by a rapid decline in circulating progesterone. Progesterone withdrawal occurs as a result of functional luteolysis, which is characterized by an increase in the enzymatic activity of 20α-hydroxysteroid dehydrogenase (20α-HSD) in the corpus luteum and is mediated by the prostaglandin F2α (PGF2α) signaling. Here, we report that the genetic knockout (KO) of Mamld1, which encodes a putative non-DNA-binding regulator of testicular steroidogenesis, caused defective functional luteolysis and subsequent parturition failure and neonatal deaths. Progesterone receptor inhibition induced the onset of parturition in pregnant KO mice, and MAMLD1 regulated the expression of Akr1c18, the gene encoding 20α-HSD, in cultured cells. Ovaries of KO mice at late gestation were morphologically unremarkable; however, Akr1c18 expression was reduced and expression of its suppressor Stat5b was markedly increased. Several other genes including Prlr, Cyp19a1, Oxtr, and Lgals3 were also dysregulated in the KO ovaries, whereas PGF2α signaling genes remained unaffected. These results highlight the role of MAMLD1 in labour initiation. MAMLD1 likely participates in functional luteolysis by regulating Stat5b and other genes, independent of the PGF2α signaling pathway. PMID:26435405

  17. MMP-12-mediated by SARM-TRIF signaling pathway contributes to IFN-γ-independent airway inflammation and AHR post RSV infection in nude mice.

    PubMed

    Long, Xiaoru; Li, Simin; Xie, Jun; Li, Wei; Zang, Na; Ren, Luo; Deng, Yu; Xie, Xiaohong; Wang, Lijia; Fu, Zhou; Liu, Enmei

    2015-02-05

    Respiratory syncytial virus (RSV) is one of the most frequently observed pathogens during infancy and childhood. However, the corresponding pathogenesis has not been determined to date. We previously demonstrated that IFN-γ plays an important role in RSV pathogenesis, and SARM-TRIF-signaling pathway could regulate the production of IFN-γ. This study is to investigate whether T cells or innate immune cells are the predominant producers of IFN-γ, and further to explore other culprits in addition to IFN-γ in the condition of RSV infection. Normal BALB/c mice and nude mice deficient in T cells were infected intranasally with RSV. Leukocytes in bronchoalveolar lavage fluid were counted, lung histopathology was examined, and airway hyperresponsiveness (AHR) was measured by whole-body plethysmography. IFN-γ and MMP-12 were detected by ELISA. MMP408, a selective MMP-12 inhibitor, was given intragastrically. Resveratrol, IFN-γ neutralizing antibody and recombinant murine IFN-γ were administered intraperitoneally. SARM and TRIF protein were semi-quantified by Western blot. siRNA was used to knock-down SARM expression. RSV induced significant airway inflammation and AHR in both mice; IFN-γ was significantly increased in BALB/c mice but not in nude mice. MMP-12 was dramatically increased in both mice but earlier in nude mice. When MMP-12 was inhibited by MMP408, RSV-induced respiratory symptoms were alleviated. SARM was significantly suppressed while TRIF was significantly enhanced in both mice strains. Following resveratrol administration in nude mice, 1) SARM inhibition was prevented, 2) TRIF and MMP-12 were correspondingly down-regulated and 3) airway disorders were subsequently alleviated. Moreover, when SARM was efficiently knocked down using siRNA, TRIF and MMP-12 were markedly enhanced, and the anti-RSV effects of resveratrol were remarkably abrogated. MMP-12 was significantly increased in the IFN-γ neutralizing antibody-treated BALB/c mice but reduced in the

  18. Early Neurobehavioral Development of Mice Lacking Endogenous PACAP.

    PubMed

    Farkas, Jozsef; Sandor, Balazs; Tamas, Andrea; Kiss, Peter; Hashimoto, Hitoshi; Nagy, Andras D; Fulop, Balazs D; Juhasz, Tamas; Manavalan, Sridharan; Reglodi, Dora

    2017-04-01

    Pituitary adenylate cyclase activating polypeptide (PACAP) is a multifunctional neuropeptide. In addition to its diverse physiological roles, PACAP has important functions in the embryonic development of various tissues, and it is also considered as a trophic factor during development and in the case of neuronal injuries. Data suggest that the development of the nervous system is severely affected by the lack of endogenous PACAP. Short-term neurofunctional outcome correlates with long-term functional deficits; however, the early neurobehavioral development of PACAP-deficient mice has not yet been evaluated. Therefore, the aim of the present study was to describe the postnatal development of physical signs and neurological reflexes in mice partially or completely lacking PACAP. We examined developmental hallmarks during the first 3 weeks of the postnatal period, during which period most neurological reflexes and motor coordination show most intensive development, and we describe the neurobehavioral development using a complex battery of tests. In the present study, we found that PACAP-deficient mice had slower weight gain throughout the observation period. Interestingly, mice partially lacking PACAP weighed significantly less than homozygous mice. There was no difference between male and female mice during the first 3 weeks. Some other signs were also more severely affected in the heterozygous mice than in the homozygous mice, such as air righting, grasp, and gait initiation reflexes. Interestingly, incisor teeth erupted earlier in mice lacking PACAP. Motor coordination, shown by the number of foot-faults on an elevated grid, was also less developed in PACAP-deficient mice. In summary, our results show that mice lacking endogenous PACAP have slower weight gain during the first weeks of development and slower neurobehavioral development regarding a few developmental hallmarks.

  19. Nonatopic asthma: in vivo airway hyperreactivity adoptively transferred to naive mice by THY-1(+) and B220(+) antigen-specific cells that lack surface expression of CD3.

    PubMed Central

    Geba, G P; Wegner, C D; Wolyniec, W W; Li, Y; Askenase, P W

    1997-01-01

    To investigate the cellular immune events contributing to airway hyperreactivity (AHR), we studied an in vivo mouse model induced by the hapten picryl (trinitrophenyl) chloride (PCl). Mice were immunized by cutaneous contact sensitization with PCl and airway challenged subsequently with picryl sulfonic acid (PSA) antigen (Ag). Increased airway resistance was produced late (24 h) after Ag challenge, disappeared by 48 h, and was associated with no decrease in diffusion capacity. AHR could be produced in PCl immune/ PSA challenged mice on day 7 or even, with challenge, as early as 1 d after contact sensitization, after adoptive transfer of immune cells lacking CD3(+) contact sensitivity effector T cells, or after transfer of Ag-specific lymphoid cells depleted of conventional T lymphocytes with surface determinants for CD3, CD4, CD8, TCR-beta, or TCR-delta molecules. Further experiments showed that development of AHR depended upon transfer of immune cells expressing surface membrane Thy-1 and B220 (CD45RA) determinants. We concluded that a novel population of Ag-specific lymphoid cells with a defined surface phenotype (Thy-1(+), CD3(-), CD4(-), CD8(-), TCR-alphabeta-, TCR-gammadelta-, and CD45RA+) is required in a mouse model for the development of AHR. PMID:9241124

  20. Mice lacking a transcriptional corepressor Tob are predisposed to cancer

    PubMed Central

    Yoshida, Yutaka; Nakamura, Takahisa; Komoda, Masato; Satoh, Hitoshi; Suzuki, Toru; Tsuzuku, Junko K.; Miyasaka, Takashi; Yoshida, Eri H.; Umemori, Hisashi; Kunisaki, Reiko K.; Tani, Kenzaburo; Ishii, Shunsuke; Mori, Shigeo; Suganuma, Masami; Noda, Tetsuo; Yamamoto, Tadashi

    2003-01-01

    tob is a member of antiproliferative family genes. Mice lacking tob are prone to spontaneous formation of tumors. The occurrence rate of diethylnitrosamine-induced liver tumors is higher in tob−/− mice than in wild-type mice. tob−/−p53−/− mice show accelerated tumor formation in comparison with single null mice. Expression of cyclin D1 mRNA is increased in the absence of Tob and is reduced by Tob. Tob acts as a transcriptional corepressor and suppresses the cyclin D1 promoter activity through an interaction with histone deacetylase. Levels of tob mRNA are often decreased in human cancers, implicating tob in cancer development. PMID:12756225

  1. Altered food consumption in mice lacking lysophosphatidic acid receptor-1.

    PubMed

    Dusaulcy, R; Daviaud, D; Pradère, J P; Grès, S; Valet, Ph; Saulnier-Blache, J S

    2009-12-01

    The release of lysophosphatidic acid (LPA) by adipocytes has previously been proposed to play a role in obesity and associated pathologies such as insulin resistance and diabetes. In the present work, the sensitivity to diet-induced obesity was studied in mice lacking one of the LPA receptor subtype (LPA1R). Conversely to what was observed in wild type (WT) mice, LPA1R-KO-mice fed a high fat diet (HFD) showed no significant increase in body weight or fat mass when compared to low fat diet (LFD). In addition, in contrast to what was observed in WT mice, LPA1R-KO mice did not exhibit over-consumption of food associated with HFD. Surprisingly, when fed a LFD, LPA1R-KO mice exhibited significant higher plasma leptin concentration and higher level of adipocyte leptin mRNA than WT mice. In conclusion, LPA1R-KO mice were found to be resistant to diet-induced obesity consecutive to a resistance to fat-induced over-consumption of food that may result at least in part from alterations in leptin expression and production.

  2. Sleep Apneas are Increased in Mice Lacking Monoamine Oxidase A

    PubMed Central

    Real, Caroline; Popa, Daniela; Seif, Isabelle; Callebert, Jacques; Launay, Jean-Marie; Adrien, Joëlle; Escourrou, Pierre

    2007-01-01

    Study Objectives: Alterations in the serotonin (5-HT) system have been suggested as a mechanism of sleep apnea in humans and rodents. The objective is to evaluate the contribution of 5-HT to this disorder. Design: We studied sleep and breathing (whole-body plethysmography) in mutant mice that lack monoamine oxidase A (MAOA) and have increased concentrations of monoamines, including 5-HT. Measurements and Results: Compared to wild-type mice, the mutants showed similar amounts of slow wave sleep (SWS) and rapid eye movement sleep (REMS), but exhibited a 3-fold increase in SWS and REMS apnea indices. Acute administration of the MAOA inhibitor clorgyline decreased REMS amounts and increased the apnea index in wild-type but not mutant mice. Parachlorophenylalanine, a 5-HT synthesis inhibitor, reduced whole brain concentrations of 5-HT in both strains, and induced a decrease in apnea index in mutant but not wild-type mice. Conclusion: Our results show that MAOA deficiency is associated with increased sleep apnea in mice and suggest that an acute or chronic excess of 5-HT contributes to this phenotype. Citation: Real C; Popa D; Seif I; Callebert J; Launay JM; Adrien J; Escourrou P. Sleep apneas are increased in mice lacking monoamine oxidase A. PMID:17969463

  3. Dihydromethysticin (DHM) Blocks Tobacco Carcinogen 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-Induced O(6)-Methylguanine in a Manner Independent of the Aryl Hydrocarbon Receptor (AhR) Pathway in C57BL/6 Female Mice.

    PubMed

    Narayanapillai, Sreekanth C; Lin, Shang-Hsuan; Leitzman, Pablo; Upadhyaya, Pramod; Baglole, Carolyn J; Xing, Chengguo

    2016-11-21

    4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a key carcinogen responsible for tobacco smoke-induced lung carcinogenesis. Among the types of DNA damage caused by NNK and its metabolite, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), O(6)-methylguanine (O(6)-mG) is likely the most carcinogen in A/J mice. Results of our previous studies showed that levels of O(6)-mG and other types of NNAL-derived DNA damage were preferentially reduced in the lung of female A/J mice upon dietary treatment with dihydromethysticin (DHM), a promising lung cancer chemopreventive agent from kava. Such a differential blockage may be mediated via an increased level of NNAL glucuronidation, thereby leading to its detoxification. The potential of the aryl hydrocarbon receptor (AhR) as an upstream target of DHM mediating these events was evaluated herein using Ahr(+/-) and Ahr(-/-) C57BL/6 female mice because DHM was reported as an AhR agonist. DHM (0.05, 0.2, and 1.0 mg/g of diet) and dihydrokavain (DHK, an inactive analogue, 1.0 mg/g of diet) were given to mice for 7 days, followed by a single intraperitoneal dose of NNK at 100 mg/kg of body weight. The effects of DHM on the amount of O(6)-mG in the lung, on the urinary ratio of glucuronidated NNAL (NNAL-Gluc) and free NNAL, and on CYP1A1/2 activity in the liver microsomes were analyzed. As observed in A/J mice, DHM treatment significantly and dose-dependently reduced the level of O(6)-mG in the target lung tissue, but there were no significant differences in O(6)-mG reduction between mice from Ahr(+/-) and Ahr(-/-) backgrounds. Similarly, in both strains, DHM at 1 mg/g of diet significantly increased the urinary ratio of NNAL-Gluc to free NNAL and CYP1A1/2 enzymatic activity in liver with no changes detected at lower DHM dosages. Because none of these effects of DHM were dependent on Ahr status, AhR clearly is not the upstream target for DHM.

  4. Motor hypertonia and lack of locomotor coordination in mutant mice lacking DSCAM

    PubMed Central

    Lemieux, Maxime; D. Laflamme, Olivier; Thiry, Louise; Boulanger-Piette, Antoine; Frenette, Jérôme

    2015-01-01

    Down syndrome cell adherence molecule (DSCAM) contributes to the normal establishment and maintenance of neural circuits. Whereas there is abundant literature regarding the role of DSCAM in the neural patterning of the mammalian retina, less is known about motor circuits. Recently, DSCAM mutation has been shown to impair bilateral motor coordination during respiration, thus causing death at birth. DSCAM mutants that survive through adulthood display a lack of locomotor endurance and coordination in the rotarod test, thus suggesting that the DSCAM mutation impairs motor control. We investigated the motor and locomotor functions of DSCAM2J mutant mice through a combination of anatomical, kinematic, force, and electromyographic recordings. With respect to wild-type mice, DSCAM2J mice displayed a longer swing phase with a limb hyperflexion at the expense of a shorter stance phase during locomotion. Furthermore, electromyographic activity in the flexor and extensor muscles was increased and coactivated over 20% of the step cycle over a wide range of walking speeds. In contrast to wild-type mice, which used lateral walk and trot at walking speed, DSCAM2J mice used preferentially less coordinated gaits, such as out-of-phase walk and pace. The neuromuscular junction and the contractile properties of muscles, as well as their muscle spindles, were normal, and no signs of motor rigidity or spasticity were observed during passive limb movements. Our study demonstrates that the DSCAM mutation induces dystonic hypertonia and a disruption of locomotor gaits. PMID:26683069

  5. Motor hypertonia and lack of locomotor coordination in mutant mice lacking DSCAM.

    PubMed

    Lemieux, Maxime; Laflamme, Olivier D; Thiry, Louise; Boulanger-Piette, Antoine; Frenette, Jérôme; Bretzner, Frédéric

    2016-03-01

    Down syndrome cell adherence molecule (DSCAM) contributes to the normal establishment and maintenance of neural circuits. Whereas there is abundant literature regarding the role of DSCAM in the neural patterning of the mammalian retina, less is known about motor circuits. Recently, DSCAM mutation has been shown to impair bilateral motor coordination during respiration, thus causing death at birth. DSCAM mutants that survive through adulthood display a lack of locomotor endurance and coordination in the rotarod test, thus suggesting that the DSCAM mutation impairs motor control. We investigated the motor and locomotor functions of DSCAM(2J) mutant mice through a combination of anatomical, kinematic, force, and electromyographic recordings. With respect to wild-type mice, DSCAM(2J) mice displayed a longer swing phase with a limb hyperflexion at the expense of a shorter stance phase during locomotion. Furthermore, electromyographic activity in the flexor and extensor muscles was increased and coactivated over 20% of the step cycle over a wide range of walking speeds. In contrast to wild-type mice, which used lateral walk and trot at walking speed, DSCAM(2J) mice used preferentially less coordinated gaits, such as out-of-phase walk and pace. The neuromuscular junction and the contractile properties of muscles, as well as their muscle spindles, were normal, and no signs of motor rigidity or spasticity were observed during passive limb movements. Our study demonstrates that the DSCAM mutation induces dystonic hypertonia and a disruption of locomotor gaits. Copyright © 2016 the American Physiological Society.

  6. 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

  7. Mice completely lacking immunoproteasomes display major alterations in antigen presentation

    PubMed Central

    Kincaid, Eleanor Z; Che, Jenny W; York, Ian; Escobar, Hernando; Reyes-Vargas, Eduardo; Delgado, Julio C.; Welsh, Raymond M; Karow, Margaret L.; Murphy, Andrew J.; Valenzuela, David M.; Yancopoulos, George D.; Rock, Kenneth L

    2011-01-01

    The importance of immunoproteasomes to antigen presentation has been unclear because animals totally lacking immunoproteasomes have not been previously developed. Here we show that dendritic cells from mice lacking the three immunoproteasome catalytic subunits display defects in presenting multiple major histocompatability (MHC) class I epitopes. During viral infection in vivo, the presentation of a majority of MHC class I epitopes is markedly reduced in immunoproteasome-deficient animals, while presentation of MHC class II peptides is unaffected. By mass spectrometry the repertoire of MHC class I-presented peptides is ~50% different and these differences are sufficient to stimulate robust transplant rejection of wild type cells in mutant mice. These results indicate that immunoproteasomes play a much more important role in antigen presentation than previously thought. PMID:22197977

  8. Phenotypic Analysis of Mice Lacking the Tmprss2-Encoded Protease

    PubMed Central

    Kim, Tom S.; Heinlein, Cynthia; Hackman, Robert C.; Nelson, Peter S.

    2006-01-01

    Tmprss2 encodes an androgen-regulated type II transmembrane serine protease (TTSP) expressed highly in normal prostate epithelium and has been implicated in prostate carcinogenesis. Although in vitro studies suggest protease-activated receptor 2 may be a substrate for TMPRSS2, the in vivo biological activities of TMPRSS2 remain unknown. We generated Tmprss2−/− mice by disrupting the serine protease domain through homologous recombination. Compared to wild-type littermates, Tmprss2−/− mice developed normally, survived to adulthood with no differences in protein levels of prostatic secretions, and exhibited no discernible abnormalities in organ histology or function. Loss of TMPRSS2 serine protease activity did not influence fertility, reduce survival, result in prostate hyperplasia or carcinoma, or alter prostatic luminal epithelial cell regrowth following castration and androgen replacement. Lack of an observable phenotype in Tmprss2−/− mice was not due to transcriptional compensation by closely related Tmprss2 homologs. We conclude that the lack of a discernible phenotype in Tmprss2−/− mice suggests functional redundancy involving one or more of the type II transmembrane serine protease family members or other serine proteases. Alternatively, TMPRSS2 may contribute a specialized but nonvital function that is apparent only in the context of stress, disease, or other systemic perturbation. PMID:16428450

  9. AHR-11797: a novel benzodiazepine antagonist

    SciTech Connect

    Johnson, D.N.; Kilpatrick, B.F.; Hannaman, P.K.

    1986-03-01

    AHR-11797(5,6-dihydro-6-methyl-1-phenyl-/sup 3/H-pyrrolo(3,2,1-ij)quinazolin-3-one) displaced /sup 3/H-flunitrazepam (IC/sub 50/ = 82 nM) and /sup 3/H-Ro 15-1877 (IC/sub 50/ = 104 nM) from rat brain synaptosomes. AHR-11797 did not protect mice from seizures induced by maximal electroshock or subcutaneous Metrazol (scMET), nor did it induce seizures in doses up to the lethal dose. However, at 31.6 mg/kg, IP, it significantly increased the anticonvulsant ED/sub 50/ of chlordiazepoxide (CDPX) from 1.9 to 31.6 mg/kg, IP. With 56.7 mg/kg, IP, of AHR-11797, CDPX was inactive in doses up to 100 mg/kg, IP. AHR-11797 did not significantly increase punished responding in the Geller and Seifter conflict procedure, but it did attenuate the effects of diazepam. Although the compound is without anticonvulsant or anxiolytic activity, it did have muscle relaxant properties. AHR-11797 blocked morphine-induced Straub tail in mice (ED/sub 50/ = 31 mg/kg, IP) and it selectively suppressed the polysnaptic linguomandibular reflex in barbiturate-anesthetized cats. The apparent muscle relaxant activity of AHR-11797 suggests that different receptor sites are involved for muscle relaxant vs. anxiolytic/anticonvulsant activities of the benzodiazepines.

  10. Increased Bone Mass in Female Mice Lacking Mast Cell Chymase

    PubMed Central

    Lind, Thomas; Gustafson, Ann-Marie; Calounova, Gabriela; Hu, Lijuan; Rasmusson, Annica; Jonsson, Kenneth B.; Wernersson, Sara; Åbrink, Magnus; Andersson, Göran; Larsson, Sune; Melhus, Håkan; Pejler, Gunnar

    2016-01-01

    Here we addressed the potential impact of chymase, a mast-cell restricted protease, on mouse bone phenotype. We show that female mice lacking the chymase Mcpt4 acquired a persistent expansion of diaphyseal bone in comparison with wild type controls, reaching a 15% larger diaphyseal cross sectional area at 12 months of age. Mcpt4-/- mice also showed increased levels of a bone anabolic serum marker and higher periosteal bone formation rate. However, they were not protected from experimental osteoporosis, suggesting that chymase regulates normal bone homeostasis rather than the course of osteoporosis. Further, the absence of Mcpt4 resulted in age-dependent upregulation of numerous genes important for bone formation but no effects on osteoclast activity. In spite of the latter, Mcpt4-/- bones had increased cortical porosity and reduced endocortical mineralization. Mast cells were found periosteally and, notably, bone-proximal mast cells in Mcpt4-/- mice were degranulated to a larger extent than in wild type mice. Hence, chymase regulates degranulation of bone mast cells, which could affect the release of mast cell-derived factors influencing bone remodelling. Together, these findings reveal a functional impact of mast cell chymase on bone. Further studies exploring the possibility of using chymase inhibitors as a strategy to increase bone volume may be warranted. PMID:27936149

  11. Lack of global epigenetic methylation defects in CBS deficient mice.

    PubMed

    Lee, Hyung-Ok; Wang, Liqun; Kuo, Yin-Ming; Gupta, Sapna; Slifker, Michael J; Li, Yue-Sheng; Andrews, Andrew J; Kruger, Warren D

    2017-01-01

    Cystathionine β-synthase (CBS) deficiency is a recessive inborn error of metabolism in which patients have extremely elevated plasma total homocysteine and have clinical manifestations in the vascular, visual, skeletal, and nervous systems. Homocysteine is an intermediary metabolite produced from the hydrolysis of S-adenosylhomocysteine (SAH), which is a by-product of methylation reactions involving the methyl-donor S-adenosylmethionine (SAM). Here, we have measured SAM, SAH, DNA and histone methylation status in an inducible mouse model of CBS deficiency to test the hypothesis that homocysteine-related phenotypes are caused by inhibition of methylation due to elevated SAH and reduced SAM/SAH ratio. We found that mice lacking CBS have elevated cellular SAH and reduced SAM/SAH ratios in both liver and kidney, but this was not associated with alterations in the level of 5-methylcytosine or various histone modifications. Using methylated DNA immunoprecipitation in combination with microarray, we found that of the 241 most differentially methylated promoter probes, 89 % were actually hypermethylated in CBS deficient mice. In addition, we did not find that changes in DNA methylation correlated well with changes in RNA expression in the livers of induced and uninduced CBS mice. Our data indicates that reduction in the SAM/SAH ratio, due to loss of CBS activity, does not result in overall hypomethylation of either DNA or histones.

  12. Cardiorespiratory Anomalies in Mice Lacking CB1 Cannabinoid Receptors

    PubMed Central

    Bastianini, Stefano; Cohen, Gary; Lo Martire, Viviana; Mazza, Roberta; Pagotto, Uberto; Quarta, Carmelo; Zoccoli, Giovanna

    2014-01-01

    Cannabinoid type 1 (CB1) receptors are expressed in the nervous and cardiovascular systems. In mice, CB1 receptor deficiency protects from metabolic consequences of a high-fat diet (HFD), increases sympathetic activity to brown fat, and entails sleep anomalies. We investigated whether sleep-wake and diet-dependent cardiorespiratory control is altered in mice lacking CB1 receptors. CB1 receptor knock-out (KO) and intact wild-type (WT) mice were fed standard diet or a HFD for 3 months, and implanted with a telemetric arterial pressure transducer and electrodes for sleep scoring. Sleep state was assessed together with arterial pressure and heart rate (home cage), or breathing (whole-body plethysmograph). Increases in arterial pressure and heart rate on passing from the light (rest) to the dark (activity) period in the KO were significantly enhanced compared with the WT. These increases were unaffected by cardiac (β1) or vascular (α1) adrenergic blockade. The breathing rhythm of the KO during sleep was also more irregular than that of the WT. A HFD increased heart rate, impaired cardiac vagal modulation, and blunted the central autonomic cardiac control during sleep. A HFD also decreased cardiac baroreflex sensitivity in the KO but not in the WT. In conclusion, we performed the first systematic study of cardiovascular function in CB1 receptor deficient mice during spontaneous wake-sleep behavior, and demonstrated that CB1 receptor KO alters cardiorespiratory control particularly in the presence of a HFD. The CB1 receptor signaling may thus play a role in physiological cardiorespiratory regulation and protect from some adverse cardiovascular consequences of a HFD. PMID:24950219

  13. Multiple Sleep Alterations in Mice Lacking Cannabinoid Type 1 Receptors

    PubMed Central

    Bastianini, Stefano; Lo Martire, Viviana; Mazza, Roberta; Pagotto, Uberto; Quarta, Carmelo; Zoccoli, Giovanna

    2014-01-01

    Cannabinoid type 1 (CB1) receptors are highly expressed in the brain and play a role in behavior control. Endogenous cannabinoid signaling is modulated by high-fat diet (HFD). We investigated the consequences of congenital lack of CB1 receptors on sleep in mice fed standard diet (SD) and HFD. CB1 cannabinoid receptor knock-out (KO) and wild-type (WT) mice were fed SD or HFD for 4 months (n = 9–10 per group). Mice were instrumented with electroencephalographic (EEG) and electromyographic electrodes. Recordings were performed during baseline (48 hours), sleep deprivation (gentle handling, 6 hours), sleep recovery (18 hours), and after cage switch (insomnia model paradigm, 6 hours). We found multiple significant effects of genotype on sleep. In particular, KO spent more time awake and less time in non-rapid-eye-movement sleep (NREMS) and rapid-eye-movement sleep (REMS) than WT during the dark (active) period but not during the light (rest) period, enhancing the day-night variation of wake-sleep amounts. KO had slower EEG theta rhythm during REMS. REMS homeostasis after sleep deprivation was less effective in KO than in WT. Finally, KO habituated more rapidly to the arousing effect of the cage-switch test than WT. We did not find any significant effects of diet or of diet x genotype interaction on sleep. The occurrence of multiple sleep alterations in KO indicates important roles of CB1 cannabinoid receptors in limiting arousal during the active period of the day, in sleep regulation, and in sleep EEG in mice. PMID:24586776

  14. Increased Bone Mass in Mice Lacking the Adipokine Apelin

    PubMed Central

    Wattanachanya, Lalita; Lu, Wei-Dar; Kundu, Ramendra K.; Wang, Liping; Abbott, Marcia J.; O'Carroll, Dylan; Quertermous, Thomas

    2013-01-01

    Adipose tissue plays an important role in skeletal homeostasis, and there is interest in identifying adipokines that influence bone mass. One such adipokine may be apelin, a ligand for the Gi-G protein-coupled receptor APJ, which has been reported to enhance mitogenesis and suppress apoptosis in MC3T3-E1 cells and primary human osteoblasts (OBs). However, it is unclear whether apelin plays a physiological role in regulating skeletal homeostasis in vivo. In this study, we compared the skeletal phenotypes of apelin knockout (APKO) and wild-type mice and investigated the direct effects of apelin on bone cells in vitro. The increased fractional cancellous bone volume at the distal femur was observed in APKO mice of both genders at 12 weeks of age and persisted until the age of 20. Cortical bone perimeter at the femoral midshaft was significantly increased in males and females at both time points. Dynamic histomorphometry revealed that APKO mice had increased rates of bone formation and mineral apposition, with evidences of accelerated OB proliferation and differentiation, without significant alteration in osteoclast activity. An in vitro study showed that apelin increased proliferation of primary mouse OBs as well as suppressed apoptosis in a dose-dependent manner with the maximum effect at 5nM. However, it had no effect on the formation of mineralized nodules. We did not observed significantly altered in osteoclast parameters in vitro. Taken together, the increased bone mass in mice lacking apelin suggested complex direct and paracrine/endocrine effects of apelin on bone, possibly via modulating insulin sensitivity. These results indicate that apelin functions as a physiologically significant antianabolic factor in bone in vivo. PMID:23584856

  15. Multiple sleep alterations in mice lacking cannabinoid type 1 receptors.

    PubMed

    Silvani, Alessandro; Berteotti, Chiara; Bastianini, Stefano; Lo Martire, Viviana; Mazza, Roberta; Pagotto, Uberto; Quarta, Carmelo; Zoccoli, Giovanna

    2014-01-01

    Cannabinoid type 1 (CB1) receptors are highly expressed in the brain and play a role in behavior control. Endogenous cannabinoid signaling is modulated by high-fat diet (HFD). We investigated the consequences of congenital lack of CB1 receptors on sleep in mice fed standard diet (SD) and HFD. CB1 cannabinoid receptor knock-out (KO) and wild-type (WT) mice were fed SD or HFD for 4 months (n = 9-10 per group). Mice were instrumented with electroencephalographic (EEG) and electromyographic electrodes. Recordings were performed during baseline (48 hours), sleep deprivation (gentle handling, 6 hours), sleep recovery (18 hours), and after cage switch (insomnia model paradigm, 6 hours). We found multiple significant effects of genotype on sleep. In particular, KO spent more time awake and less time in non-rapid-eye-movement sleep (NREMS) and rapid-eye-movement sleep (REMS) than WT during the dark (active) period but not during the light (rest) period, enhancing the day-night variation of wake-sleep amounts. KO had slower EEG theta rhythm during REMS. REMS homeostasis after sleep deprivation was less effective in KO than in WT. Finally, KO habituated more rapidly to the arousing effect of the cage-switch test than WT. We did not find any significant effects of diet or of diet x genotype interaction on sleep. The occurrence of multiple sleep alterations in KO indicates important roles of CB1 cannabinoid receptors in limiting arousal during the active period of the day, in sleep regulation, and in sleep EEG in mice.

  16. Optical stimulation in mice lacking the TRPV1 channel

    NASA Astrophysics Data System (ADS)

    Suh, Eul; Izzo Matic, Agnella; Otting, Margarete; Walsh, Joseph T., Jr.; Richter, Claus-Peter

    2009-02-01

    Lasers can be used to stimulate neural tissue, including the sciatic nerve or auditory neurons. Wells and coworkers suggested that neural tissue is likely stimulated by heat.[1,2] Ion channels that can be activated by heat are the TRPV channels, a subfamily of the Transient Receptor Potential (TRP) ion channels. TRPV channels are nonselective cation channels found in sensory neurons involved in nociception. In addition to various chemicals, TRPV channels can also be thermally stimulated. The activation temperature for the different TRPV channels varies and is 43°C for TRPV1 and 39°C for TRPV3. By performing an immunohistochemical staining procedure on frozen 20 μm cochlear slices using a primary TRPV1 antibody, we observed specific immunostaining of the spiral ganglion cells. Here we show that in mice that lack the gene for the TRPV1 channel optical radiation cannot evoke action potentials on the auditory nerve.

  17. Lethal Cardiomyopathy in Mice Lacking Transferrin Receptor in the Heart.

    PubMed

    Xu, Wenjing; Barrientos, Tomasa; Mao, Lan; Rockman, Howard A; Sauve, Anthony A; Andrews, Nancy C

    2015-10-20

    Both iron overload and iron deficiency have been associated with cardiomyopathy and heart failure, but cardiac iron utilization is incompletely understood. We hypothesized that the transferrin receptor (Tfr1) might play a role in cardiac iron uptake and used gene targeting to examine the role of Tfr1 in vivo. Surprisingly, we found that decreased iron, due to inactivation of Tfr1, was associated with severe cardiac consequences. Mice lacking Tfr1 in the heart died in the second week of life and had cardiomegaly, poor cardiac function, failure of mitochondrial respiration, and ineffective mitophagy. The phenotype could only be rescued by aggressive iron therapy, but it was ameliorated by administration of nicotinamide riboside, an NAD precursor. Our findings underscore the importance of both Tfr1 and iron in the heart, and may inform therapy for patients with heart failure.

  18. Phenotypic analysis of mice completely lacking netrin 1.

    PubMed

    Yung, Andrea R; Nishitani, Allison M; Goodrich, Lisa V

    2015-11-01

    Netrin 1 (Ntn1) is a multifunctional guidance cue expressed in the ventricular zone and floor plate of the embryonic neural tube. Although Ntn1 is best known for acting as an axon guidance cue through Dcc and neogenin receptors, it is also thought to regulate neuronal survival and blood vessel development through Unc5 family receptors. However, the Ntn1 gene trap mutant mouse does not display all the phenotypes predicted from in vitro assays or analyses of mice lacking predicted receptors. Since the gene trap strain still produces wild-type Ntn1 protein, it is unclear whether the absence of phenotypes reflects the activity of alternative cues or of residual Ntn1. To resolve the full contribution of Ntn1 to development, we generated a null allele of Ntn1 and re-examined tissues exhibiting phenotypic discrepancies between receptor mutants and Ntn1 hypomorphs. We found that in Ntn1 null animals commissural axons rarely cross the midline, resulting in a strongly enhanced phenotype relative to Ntn1 hypomorphs, which retain many axons with normal trajectories. Thus, low levels of Ntn1 can account for persistent attraction to the midline in hypomorphs. By contrast, Ntn1 null mice do not show all of the phenotypes reported for Unc5 receptor mutants, indicating that Ntn1 is not necessarily the dominant ligand for Unc5 family members in vivo and ruling out primary roles in survival or angiogenesis. © 2015. Published by The Company of Biologists Ltd.

  19. Phenotypic analysis of mice completely lacking netrin 1

    PubMed Central

    Yung, Andrea R.; Nishitani, Allison M.; Goodrich, Lisa V.

    2015-01-01

    Netrin 1 (Ntn1) is a multifunctional guidance cue expressed in the ventricular zone and floor plate of the embryonic neural tube. Although Ntn1 is best known for acting as an axon guidance cue through Dcc and neogenin receptors, it is also thought to regulate neuronal survival and blood vessel development through Unc5 family receptors. However, the Ntn1 gene trap mutant mouse does not display all the phenotypes predicted from in vitro assays or analyses of mice lacking predicted receptors. Since the gene trap strain still produces wild-type Ntn1 protein, it is unclear whether the absence of phenotypes reflects the activity of alternative cues or of residual Ntn1. To resolve the full contribution of Ntn1 to development, we generated a null allele of Ntn1 and re-examined tissues exhibiting phenotypic discrepancies between receptor mutants and Ntn1 hypomorphs. We found that in Ntn1 null animals commissural axons rarely cross the midline, resulting in a strongly enhanced phenotype relative to Ntn1 hypomorphs, which retain many axons with normal trajectories. Thus, low levels of Ntn1 can account for persistent attraction to the midline in hypomorphs. By contrast, Ntn1 null mice do not show all of the phenotypes reported for Unc5 receptor mutants, indicating that Ntn1 is not necessarily the dominant ligand for Unc5 family members in vivo and ruling out primary roles in survival or angiogenesis. PMID:26395479

  20. Enhanced insulin clearance in mice lacking TRPM8 channels

    PubMed Central

    McCoy, Daniel D.; Zhou, Ligang; Nguyen, Anh-Khoi; Watts, Alan G.; Donovan, Casey M.

    2013-01-01

    Blood glucose concentration is tightly regulated by the rate of insulin secretion and clearance, a process partially controlled by sensory neurons serving as metabolic sensors in relevant tissues. The activity of these neurons is regulated by the products of metabolism which regulate transmitter release, and recent evidence suggests that neuronally expressed ion channels of the transient receptor potential (TRP) family function in this critical process. Here, we report the novel finding that the cold and menthol-gated channel TRPM8 is necessary for proper insulin homeostasis. Mice lacking TRPM8 respond normally to a glucose challenge while exhibiting prolonged hypoglycemia in response to insulin. Additionally, Trpm8-/- mice have increased rates of insulin clearance compared with wild-type animals and increased expression of insulin-degrading enzyme in the liver. TRPM8 channels are not expressed in the liver, but TRPM8-expressing sensory afferents innervate the hepatic portal vein, suggesting a TRPM8-mediated neuronal control of liver insulin clearance. These results demonstrate that TRPM8 is a novel regulator of serum insulin and support the role of sensory innervation in metabolic homeostasis. PMID:23651844

  1. Mice Lacking Hbp1 Function Are Viable and Fertile

    PubMed Central

    Wilhelm, Dagmar; Jans, David A.; Bowles, Josephine; Koopman, Peter

    2017-01-01

    Fetal germ cell development is tightly regulated by the somatic cell environment, and is characterised by cell cycle states that differ between XY and XX gonads. In the testis, gonocytes enter G1/G0 arrest from 12.5 days post coitum (dpc) in mice and maintain cell cycle arrest until after birth. Failure to correctly maintain G1/G0 arrest can result in loss of germ cells or, conversely, germ cell tumours. High mobility group box containing transcription factor 1 (HBP1) is a transcription factor that was previously identified in fetal male germ cells at the time of embryonic cell cycle arrest. In somatic cells, HBP1 is classified as a tumour suppressor protein, known to regulate proliferation and senescence. We therefore investigated the possible role of HBP1 in the initiation and maintenance of fetal germ cell G1/G0 arrest using the mouse model. We identified two splice variants of Hbp1, both of which are expressed in XY and XX fetal gonads, but only one of which is localised to the nucleus in in vitro assays. To investigate Hbp1 loss of function, we used embryonic stem (ES) cells carrying a Genetrap mutation for Hbp1 to generate mice lacking Hbp1 function. We found that Hbp1-genetrap mouse mutant germ cells proliferated correctly throughout development, and adult males were viable and fertile. Multiple Hbp1-LacZ reporter mouse lines were generated, unexpectedly revealing Hbp1 embryonic expression in hair follicles, eye and limbs. Lastly, in a model of defective germ cell G1/G0 arrest, the Rb1-knockout model, we found no evidence for Hbp1 mis-regulation, suggesting that the reported RB1-HBP1 interaction is not critical in the germline, despite co-expression. PMID:28107452

  2. Knockout of the aryl hydrocarbon receptor results in distinct hepatic and renal phenotypes in rats and mice

    SciTech Connect

    Harrill, Joshua A.; Hukkanen, Renee R.; Lawson, Marie; Martin, Greg; Gilger, Brian; Soldatow, Valerie; LeCluyse, Edward L.; Budinsky, Robert A.; Rowlands, J. Craig; Thomas, Russell S.

    2013-10-15

    The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor which plays a role in the development of multiple tissues and is activated by a large number of ligands, including 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In order to examine the roles of the AHR in both normal biological development and response to environmental chemicals, an AHR knockout (AHR-KO) rat model was created and compared with an existing AHR-KO mouse. AHR-KO rats harboring either 2-bp or 29-bp deletion mutation in exon 2 of the AHR were created on the Sprague–Dawley genetic background using zinc-finger nuclease (ZFN) technology. Rats harboring either mutation type lacked expression of AHR protein in the liver. AHR-KO rats were also insensitive to thymic involution, increased hepatic weight and the induction of AHR-responsive genes (Cyp1a1, Cyp1a2, Cyp1b1, Ahrr) following acute exposure to 25 μg/kg TCDD. AHR-KO rats had lower basal expression of transcripts for these genes and also accumulated ∼ 30–45-fold less TCDD in the liver at 7 days post-exposure. In untreated animals, AHR-KO mice, but not AHR-KO rats, had alterations in serum analytes indicative of compromised hepatic function, patent ductus venosus of the liver and persistent hyaloid arteries in the eye. AHR-KO rats, but not AHR-KO mice, displayed pathological alterations to the urinary tract: bilateral renal dilation (hydronephrosis), secondary medullary tubular and uroepithelial degenerative changes and bilateral ureter dilation (hydroureter). The present data indicate that the AHR may play significantly different roles in tissue development and homeostasis and toxicity across rodent species. - Highlights: • An AHR knockout rat was generated on a Sprague–Dawley outbred background. • AHR-KO rats lack expression of AHR protein. • AHR-KO rats are insensitive to TCDD-mediated effects. • Data suggests difference in the role of AHR in tissue development of rats and mice. • Abnormalities in vascular

  3. Deficiency in Aryl Hydrocarbon Receptor (AHR) Expression throughout Aging Alters Gene Expression Profiles in Murine Long-Term Hematopoietic Stem Cells

    PubMed Central

    Bennett, John A.; Singh, Kameshwar P.; Unnisa, Zeenath; Welle, Stephen L.; Gasiewicz, Thomas A.

    2015-01-01

    Dysregulation of hematopoietic stem cell (HSC) signaling can contribute to the development of diseases of the blood system. Lack of aryl hydrocarbon receptor (AhR) has been associated with alterations in gene expression related to HSC function and the subsequent development of a myeloproliferative disorder in aging female mice. We sorted the most primitive population of HSCs with the highest stem cell potential (Long-term, or LT-HSCs) from 18-month-old AhR-null-allele (AhR-KO) and WT mice and analyzed gene expression using microarray to determine alterations in gene expression and cell signaling networks in HSCs that could potentially contribute to the aging phenotype of AhR-KO mice. Comparisons with previous array data from 8-week old mice indicated that aging alone is sufficient to alter gene expression. In addition, a significant number of gene expression differences were observed in aged LT-HSCs that are dependent on both aging and lack of AhR. Pathway analysis of these genes revealed networks related to hematopoietic stem cell activity or function. qPCR was used to confirm the differential expression of a subset of these genes, focusing on genes that may represent novel AhR targets due to the presence of a putative AhR binding site in their upstream regulatory region. We verified differential expression of PDGF-D, Smo, Wdfy1, Zbtb37 and Zfp382. Pathway analysis of this subset of genes revealed overlap between cellular functions of the novel AhR targets and AhR itself. Lentiviral-mediated knockdown of AhR in lineage-negative hematopoietic cells was sufficient to induce changes in all five of the candidate AhR targets identified. Taken together, these data suggest a role for AhR in HSC functional regulation, and identify novel HSC AhR target genes that may contribute to the phenotypes observed in AhR-KO mice. PMID:26208102

  4. Role of DNA methylation of AHR1 and AHR2 promoters in differential sensitivity to PCBs in Atlantic Killifish, Fundulus heteroclitus.

    PubMed

    Aluru, Neelakanteswar; Karchner, Sibel I; Hahn, Mark E

    2011-01-17

    Atlantic killifish (Fundulus heteroclitus) inhabiting the PCB-contaminated Superfund site in New Bedford Harbor (MA, USA) have evolved genetic resistance to the toxic effects of these compounds. They also lack induction of cytochrome P4501A (CYP1A) and other aryl hydrocarbon receptor (AHR)-dependent responses after exposure to AHR agonists, suggesting an overall down-regulation of the AHR signaling pathway. In this study, we hypothesized that the genetic resistance is due to altered AHR expression resulting from hypermethylation of DNA in the promoter region of AHR genes in fish inhabiting New Bedford Harbor. To test this hypothesis, we cloned and sequenced AHR1 and AHR2 promoter regions and employed bisulfite conversion-polymerase chain reaction (BS-PCR) followed by clonal analysis to compare the methylation status of CpG islands of AHR1 and AHR2 in livers of adult killifish collected from New Bedford Harbor and a reference site (Scorton Creek, MA). No significant differences in methylation profiles were observed in either AHR1 or AHR2 promoter regions between NBH and SC fish. However, hypermethylation of the AHR1 promoter correlated with low expression of transcripts in the liver in both populations. In comparison to AHR1, hepatic mRNA expression of AHR2 is high and its promoter is hypomethylated. Taken together, our results suggest that genetic resistance to contaminants in NBH fish is not due to altered methylation of AHR promoter regions, but that promoter methylation may control tissue-specific expression of AHR genes in killifish.

  5. Aberrant Development of Thymocytes in Mice Lacking Laminin-2

    PubMed Central

    Magner, William J.; Chang, Andrew C.; Owens, Jennie; Hong, M-J. P.; Brooks, Andrew

    2000-01-01

    In previous in vitro studies, we proposed a role for the extracellular matrix component, laminin- 2, and its integrin receptor, VLA-6, in thymocyte development. The characterization of two dystrophic mouse strains with different defects in laminin-2 allowed us to examine this proposal in vivo. Mice deficient in laminin-2, dy/dy, show a significant reduction in thymus size and number of thymocytes compared to normal littermates. These mice also exhibited apparent alterations of thymic architecture. Examination of the CD4/CD8 populations in dy/dy thymi showed large relative increases in the DN (CD4-CD8-) and SP (CD4+CD8-, CD4-CD8+) populations and a significant decrease in the DP (CD4+CD8+) population. Further examination of the DN population for CD44 and CD25 expression showed a remarkable decrease in the more mature pre-T cell populations. Analysis of apoptosis in situ, and by flow cytometry, in dy/dy thymi revealed a significant increase in apoptotic DN thymocytes in the capsule and subcapsular regions. Interestingly, thymocyte development appeared to proceed normally in dystrophic mice expressing a mutant form of laminin-2, dy2J, as well as, in fetal and neonatal dy/dy mice. We propose that laminin-2 plays an active role in thymocyte development by delivering cell survival and differentiation signals at specific stages of development in young adult mice. PMID:11097211

  6. Prolonged fear responses in mice lacking dopamine D1 receptor.

    PubMed

    El-Ghundi, M; O'Dowd, B F; George, S R

    2001-02-16

    Dopamine is an important neurotransmitter involved in learning and memory including emotional memory. The involvement of dopamine in conditioned fear has been widely documented. However, little is known about the molecular mechanisms that underlie contextual fear conditioning and memory consolidation. To address this issue, we used dopamine D1-deficient mice (D1-/-) and their wild-type (D1+/+) and heterozygote (D1+/-) siblings to assess aversive learning and memory. We quantified two different aspects of fear responses to an environment where the mice have previously received unsignaled footshocks. Using one-trial step-through passive avoidance and conditioned freezing paradigms, mice were conditioned to receive mild inescapable footshocks then tested for acquisition, retention and extinction of conditioned fear responses 5 min after and up to 45-90 days post-training. No differences were observed among any of the genotypes in the acquisition of passive avoidance response or fear-induced freezing behavior. However, with extended testing, D1-/- mice exhibited prolonged retention and delayed extinction of conditioned fear responses in both tasks, suggesting that D1-/- mice are capable of acquiring aversive learning normally. These findings demonstrate that the dopamine D1 receptor is not important for acquisition or consolidation of aversive learning and memory but has an important role in modulating the extinction of fear memory.

  7. Knockout of the aryl hydrocarbon receptor results in distinct hepatic and renal phenotypes in rats and mice.

    PubMed

    Harrill, Joshua A; Hukkanen, Renee R; Lawson, Marie; Martin, Greg; Gilger, Brian; Soldatow, Valerie; Lecluyse, Edward L; Budinsky, Robert A; Rowlands, J Craig; Thomas, Russell S

    2013-10-15

    The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor which plays a role in the development of multiple tissues and is activated by a large number of ligands, including 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In order to examine the roles of the AHR in both normal biological development and response to environmental chemicals, an AHR knockout (AHR-KO) rat model was created and compared with an existing AHR-KO mouse. AHR-KO rats harboring either 2-bp or 29-bp deletion mutation in exon 2 of the AHR were created on the Sprague-Dawley genetic background using zinc-finger nuclease (ZFN) technology. Rats harboring either mutation type lacked expression of AHR protein in the liver. AHR-KO rats were also insensitive to thymic involution, increased hepatic weight and the induction of AHR-responsive genes (Cyp1a1, Cyp1a2, Cyp1b1, Ahrr) following acute exposure to 25 μg/kg TCDD. AHR-KO rats had lower basal expression of transcripts for these genes and also accumulated ~30-45-fold less TCDD in the liver at 7 days post-exposure. In untreated animals, AHR-KO mice, but not AHR-KO rats, had alterations in serum analytes indicative of compromised hepatic function, patent ductus venosus of the liver and persistent hyaloid arteries in the eye. AHR-KO rats, but not AHR-KO mice, displayed pathological alterations to the urinary tract: bilateral renal dilation (hydronephrosis), secondary medullary tubular and uroepithelial degenerative changes and bilateral ureter dilation (hydroureter). The present data indicate that the AHR may play significantly different roles in tissue development and homeostasis and toxicity across rodent species.

  8. Collagen Fibril Ultrastructure in Mice Lacking Discoidin Domain Receptor 1.

    PubMed

    Tonniges, Jeffrey R; Albert, Benjamin; Calomeni, Edward P; Roy, Shuvro; Lee, Joan; Mo, Xiaokui; Cole, Susan E; Agarwal, Gunjan

    2016-06-01

    The quantity and quality of collagen fibrils in the extracellular matrix (ECM) have a pivotal role in dictating biological processes. Several collagen-binding proteins (CBPs) are known to modulate collagen deposition and fibril diameter. However, limited studies exist on alterations in the fibril ultrastructure by CBPs. In this study, we elucidate how the collagen receptor, discoidin domain receptor 1 (DDR1) regulates the collagen content and ultrastructure in the adventitia of DDR1 knock-out (KO) mice. DDR1 KO mice exhibit increased collagen deposition as observed using Masson's trichrome. Collagen ultrastructure was evaluated in situ using transmission electron microscopy, scanning electron microscopy, and atomic force microscopy. Although the mean fibril diameter was not significantly different, DDR1 KO mice had a higher percentage of fibrils with larger diameter compared with their wild-type littermates. No significant differences were observed in the length of D-periods. In addition, collagen fibrils from DDR1 KO mice exhibited a small, but statistically significant, increase in the depth of the fibril D-periods. Consistent with these observations, a reduction in the depth of D-periods was observed in collagen fibrils reconstituted with recombinant DDR1-Fc. Our results elucidate how DDR1 modulates collagen fibril ultrastructure in vivo, which may have important consequences in the functional role(s) of the underlying ECM.

  9. Collagen Fibril Ultrastructure in Mice Lacking Discoidin Domain Receptor 1

    PubMed Central

    Tonniges, Jeffrey R.; Albert, Benjamin; Calomeni, Edward P.; Roy, Shuvro; Lee, Joan; Mo, Xiaokui; Cole, Susan E.; Agarwal, Gunjan

    2016-01-01

    The quantity and quality of collagen fibrils in the extracellular matrix (ECM) have a pivotal role in dictating biological processes. Several collagen-binding proteins (CBPs) are known to modulate collagen deposition and fibril diameter. However, limited studies exist on alterations in the fibril ultrastructure by CBPs. In this study, we elucidate how the collagen receptor, discoidin domain receptor 1 (DDR1) regulates the collagen content and ultrastructure in the adventitia of DDR1 knock-out (KO) mice. DDR1 KO mice exhibit increased collagen deposition as observed using Masson’s trichrome. Collagen ultrastructure was evaluated in situ using transmission electron microscopy, scanning electron microscopy, and atomic force microscopy. Although the mean fibril diameter was not significantly different, DDR1 KO mice had a higher percentage of fibrils with larger diameter compared with their wild-type littermates. No significant differences were observed in the length of D-periods. In addition, collagen fibrils from DDR1 KO mice exhibited a small, but statistically significant, increase in the depth of the fibril D-periods. Consistent with these observations, a reduction in the depth of D-periods was observed in collagen fibrils reconstituted with recombinant DDR1-Fc. Our results elucidate how DDR1 modulates collagen fibril ultrastructure in vivo, which may have important consequences in the functional role(s) of the underlying ECM. PMID:27329311

  10. Hypogonadotropic hypogonadism in mice lacking a functional Kiss1 gene

    PubMed Central

    d'Anglemont de Tassigny, Xavier; Fagg, Lisa A.; Dixon, John P. C.; Day, Kate; Leitch, Harry G.; Hendrick, Alan G.; Zahn, Dirk; Franceschini, Isabelle; Caraty, Alain; Carlton, Mark B. L.; Aparicio, Samuel A. J. R.; Colledge, William H.

    2007-01-01

    The G protein-coupled receptor GPR54 (AXOR12, OT7T175) is central to acquisition of reproductive competency in mammals. Peptide ligands (kisspeptins) for this receptor are encoded by the Kiss1 gene, and administration of exogenous kisspeptins stimulates hypothalamic gonadotropin-releasing hormone (GnRH) release in several species, including humans. To establish that kisspeptins are the authentic agonists of GPR54 in vivo and to determine whether these ligands have additional physiological functions we have generated mice with a targeted disruption of the Kiss1 gene. Kiss1-null mice are viable and healthy with no apparent abnormalities but fail to undergo sexual maturation. Mutant female mice do not progress through the estrous cycle, have thread-like uteri and small ovaries, and do not produce mature Graffian follicles. Mutant males have small testes, and spermatogenesis arrests mainly at the early haploid spermatid stage. Both sexes have low circulating gonadotropin (luteinizing hormone and follicle-stimulating hormone) and sex steroid (β-estradiol or testosterone) hormone levels. Migration of GnRH neurons into the hypothalamus appears normal with appropriate axonal connections to the median eminence and total GnRH content. The hypothalamic–pituitary axis is functional in these mice as shown by robust luteinizing hormone secretion after peripheral administration of kisspeptin. The virtually identical phenotype of Gpr54- and Kiss1-null mice provides direct proof that kisspeptins are the true physiological ligand for the GPR54 receptor in vivo. Kiss1 also does not seem to play a vital role in any other physiological processes other than activation of the hypothalamic–pituitary–gonadal axis, and loss of Kiss1 cannot be overcome by compensatory mechanisms. PMID:17563351

  11. Cerebellar deficits and hyperactivity in mice lacking Smad4.

    PubMed

    Zhou, Yong-Xing; Zhao, Mingrui; Li, Dan; Shimazu, Kazuhiro; Sakata, Kazuko; Deng, Chu-Xia; Lu, Bai

    2003-10-24

    Smad4 is a central mediator of TGF-beta signals, which are known to play essential roles in many biological processes. Using a Cre-loxP approach to overcome early embryonic lethality, we have studied functions of TGF-beta/Smad4 signals in the central nervous system (CNS). No obvious deficits were detected in mice carrying the targeted disruption of Smad4 in the CNS. The overall morphology of the hippocampus appeared normal. There was no change in the proliferation of neuronal precursor cells, nor in several forms of synaptic plasticity. In contrast, deletion of Smad4 resulted in a marked decrease in the number of cerebellar Purkinje cells and parvalbumin-positive interneurons. Accompanied by the abnormality in the cerebellum, mutant mice also exhibited significantly increased vertical activity. Thus, our study reveals an unexpected role for Smad4 in cerebellar development and in the control of motor function.

  12. Lack of teratogenicity of aluminum hydroxide in mice

    SciTech Connect

    Domingo, J.S.; Mercedes Gomez, M.A.B.; Corbella, J.

    1989-01-01

    The embryotoxic and teratogenic potential of aluminum hydroxide, a therapeutic drug used as an antacid and phosphate binder, was investigated in Swiss mice. Mated female mice were given by gavage daily doses of 0, 66.5, 133 or 266 mg/kg of A1(OH)/sub 3/ on gestation days 6 through 15 and killed on gestation day 18. Females were evaluated for body weight gain, food consumption appearance and behavior, survival rates, and reproduction data. No significant effects attributable to A1(OH)/sub 3/ were noted in comparisons of maternal body weight and food consumption values, appearance and behavior. No treatment-related changes were recorded in the number of total implants, resorptions, the number of live and dead fetuses, fetal size parameters or fetal sex distribution data. Gross external, soft tissue and skeletal examination of the A1-treated fetuses did not reveal differences at any dose in comparison with the controls. Thus, no evidence of maternal toxicity, embryo/fetal toxicity or teratogenicity was observed with A1(OH)/sub 3/ in mice.

  13. Defective thrombus formation in mice lacking coagulation factor XII

    PubMed Central

    Renné, Thomas; Pozgajová, Miroslava; Grüner, Sabine; Schuh, Kai; Pauer, Hans-Ulrich; Burfeind, Peter; Gailani, David; Nieswandt, Bernhard

    2005-01-01

    Blood coagulation is thought to be initiated by plasma protease factor VIIa in complex with the membrane protein tissue factor. In contrast, coagulation factor XII (FXII)–mediated fibrin formation is not believed to play an important role for coagulation in vivo. We used FXII-deficient mice to study the contributions of FXII to thrombus formation in vivo. Intravital fluorescence microscopy and blood flow measurements in three distinct arterial beds revealed a severe defect in the formation and stabilization of platelet-rich occlusive thrombi. Although FXII-deficient mice do not experience spontaneous or excessive injury-related bleeding, they are protected against collagen- and epinephrine-induced thromboembolism. Infusion of human FXII into FXII-null mice restored injury-induced thrombus formation. These unexpected findings change the long-standing concept that the FXII-induced intrinsic coagulation pathway is not important for clotting in vivo. The results establish FXII as essential for thrombus formation, and identify FXII as a novel target for antithrombotic therapy. PMID:16009717

  14. Mice Lacking Endoglin in Macrophages Show an Impaired Immune Response

    PubMed Central

    Ojeda-Fernández, Luisa; Recio-Poveda, Lucía; Aristorena, Mikel; Lastres, Pedro; Blanco, Francisco J.; Sanz-Rodríguez, Francisco; Gallardo-Vara, Eunate; de las Casas-Engel, Mateo; Corbí, Ángel; Arthur, Helen M.; Bernabeu, Carmelo; Botella, Luisa M.

    2016-01-01

    Endoglin is an auxiliary receptor for members of the TGF-β superfamily and plays an important role in the homeostasis of the vessel wall. Mutations in endoglin gene (ENG) or in the closely related TGF-β receptor type I ACVRL1/ALK1 are responsible for a rare dominant vascular dysplasia, the Hereditary Hemorrhagic Telangiectasia (HHT), or Rendu-Osler-Weber syndrome. Endoglin is also expressed in human macrophages, but its role in macrophage function remains unknown. In this work, we show that endoglin expression is triggered during the monocyte-macrophage differentiation process, both in vitro and during the in vivo differentiation of blood monocytes recruited to foci of inflammation in wild-type C57BL/6 mice. To analyze the role of endoglin in macrophages in vivo, an endoglin myeloid lineage specific knock-out mouse line (Engfl/flLysMCre) was generated. These mice show a predisposition to develop spontaneous infections by opportunistic bacteria. Engfl/flLysMCre mice also display increased survival following LPS-induced peritonitis, suggesting a delayed immune response. Phagocytic activity is impaired in peritoneal macrophages, altering one of the main functions of macrophages which contributes to the initiation of the immune response. We also observed altered expression of TGF-β1 target genes in endoglin deficient peritoneal macrophages. Overall, the altered immune activity of endoglin deficient macrophages could help to explain the higher rate of infectious diseases seen in HHT1 patients. PMID:27010826

  15. Lack of acrosome formation in mice lacking a Golgi protein, GOPC

    PubMed Central

    Yao, Ryoji; Ito, Chizuru; Natsume, Yasuko; Sugitani, Yoshinobu; Yamanaka, Hitomi; Kuretake, Shoji; Yanagida, Kaoru; Sato, Akira; Toshimori, Kiyotaka; Noda, Tetsuo

    2002-01-01

    The acrosome is a unique organelle that plays an important role at the site of sperm–zona pellucida binding during the fertilization process, and is lost in globozoospermia, an inherited infertility syndrome in humans. Although the acrosome is known to be derived from the Golgi apparatus, molecular mechanisms underlying acrosome formation are largely unknown. Here we show that Golgi-associated PDZ- and coiled-coil motif-containing protein (GOPC), a recently identified Golgi-associated protein, is predominantly localized at the trans-Golgi region in round spermatids, and male mice in which GOPC has been disrupted are infertile with globozoospermia. The primary defect was the fragmentation of acrosomes in early round spermatids, and abnormal vesicles that failed to fuse to developing acrosomes were apparent. In later stages, nuclear malformation and an abnormal arrangement of mitochondria, which are also characteristic features of human globozoospermia, were observed. Interestingly, intracytoplasmic sperm injection (ICSI) of such malformed sperm into oocytes resulted in cleavage into blastocysts only when injected oocytes were activated. Thus, GOPC provides important clues to understanding the mechanisms underlying spermatogenesis, and the GOPC-deficient mouse may be a unique and valuable model for human globozoospermia. PMID:12149515

  16. Fenofibrate, but not ezetimibe, prevents fatty liver disease in mice lacking phosphatidylethanolamine N-methyltransferase[S

    PubMed Central

    van der Veen, Jelske N.; Lingrell, Susanne; Gao, Xia; Takawale, Abhijit; Kassiri, Zamaneh; Vance, Dennis E.; Jacobs, René L.

    2017-01-01

    Mice lacking phosphatidylethanolamine N-methyltransferase (PEMT) are protected from high-fat diet (HFD)-induced obesity and insulin resistance. However, these mice develop severe nonalcoholic fatty liver disease (NAFLD) when fed the HFD, which is mainly due to inadequate secretion of VLDL particles. Our aim was to prevent NAFLD development in mice lacking PEMT. We treated Pemt−/− mice with either ezetimibe or fenofibrate to see if either could ameliorate liver disease in these mice. Ezetimibe treatment did not reduce fat accumulation in Pemt−/− livers, nor did it reduce markers for hepatic inflammation or fibrosis. Fenofibrate, conversely, completely prevented the development of NAFLD in Pemt−/− mice: hepatic lipid levels, as well as markers of endoplasmic reticulum stress, inflammation, and fibrosis, in fenofibrate-treated Pemt−/− mice were similar to those in Pemt+/+ mice. Importantly, Pemt−/− mice were still protected against HFD-induced obesity and insulin resistance. Moreover, fenofibrate partially reversed hepatic steatosis and fibrosis in Pemt−/− mice when treatment was initiated after NAFLD had already been established. Increasing hepatic fatty acid oxidation can compensate for the lower VLDL-triacylglycerol secretion rate and prevent/reverse fatty liver disease in mice lacking PEMT. PMID:28159867

  17. Motor learning of mice lacking cerebellar Purkinje cells.

    PubMed

    Porras-García, M Elena; Ruiz, Rocío; Pérez-Villegas, Eva M; Armengol, José Á

    2013-01-01

    The cerebellum plays a key role in the acquisition and execution of motor tasks whose physiological foundations were postulated on Purkinje cells' long-term depression (LTD). Numerous research efforts have been focused on understanding the cerebellum as a site of learning and/or memory storage. However, the controversy on which part of the cerebellum participates in motor learning, and how the process takes place, remains unsolved. In fact, it has been suggested that cerebellar cortex, deep cerebellar nuclei, and/or their combination with some brain structures other than the cerebellum are responsible for motor learning. Different experimental approaches have been used to tackle this question (cerebellar lesions, pharmacological agonist and/or antagonist of cerebellar neurotransmitters, virus tract tracings, etc.). One of these approaches is the study of spontaneous mutations affecting the cerebellar cortex and depriving it of its main input-output organizer (i.e., the Purkinje cell). In this review, we discuss the results obtained in our laboratory in motor learning of both Lurcher (Lc/+) and tambaleante (tbl/tbl) mice as models of Purkinje-cell-devoid cerebellum.

  18. Motor learning of mice lacking cerebellar Purkinje cells

    PubMed Central

    Porras-García, M. Elena; Ruiz, Rocío; Pérez-Villegas, Eva M.; Armengol, José Á.

    2013-01-01

    The cerebellum plays a key role in the acquisition and execution of motor tasks whose physiological foundations were postulated on Purkinje cells' long-term depression (LTD). Numerous research efforts have been focused on understanding the cerebellum as a site of learning and/or memory storage. However, the controversy on which part of the cerebellum participates in motor learning, and how the process takes place, remains unsolved. In fact, it has been suggested that cerebellar cortex, deep cerebellar nuclei, and/or their combination with some brain structures other than the cerebellum are responsible for motor learning. Different experimental approaches have been used to tackle this question (cerebellar lesions, pharmacological agonist and/or antagonist of cerebellar neurotransmitters, virus tract tracings, etc.). One of these approaches is the study of spontaneous mutations affecting the cerebellar cortex and depriving it of its main input–output organizer (i.e., the Purkinje cell). In this review, we discuss the results obtained in our laboratory in motor learning of both Lurcher (Lc/+) and tambaleante (tbl/tbl) mice as models of Purkinje-cell-devoid cerebellum. PMID:23630472

  19. Increased brain-derived neurotrophic factor (BDNF) protein concentrations in mice lacking brain serotonin.

    PubMed

    Kronenberg, Golo; Mosienko, Valentina; Gertz, Karen; Alenina, Natalia; Hellweg, Rainer; Klempin, Friederike

    2016-04-01

    The interplay between BDNF signaling and the serotonergic system remains incompletely understood. Using a highly sensitive enzyme-linked immunosorbent assay, we studied BDNF concentrations in hippocampus and cortex of two mouse models of altered serotonin signaling: tryptophan hydroxylase (Tph)2-deficient (Tph2 (-/-)) mice lacking brain serotonin and serotonin transporter (SERT)-deficient (SERT(-/-)) mice lacking serotonin re-uptake. Surprisingly, hippocampal BDNF was significantly elevated in Tph2 (-/-) mice, whereas no significant changes were observed in SERT(-/-) mice. Furthermore, BDNF levels were increased in the prefrontal cortex of Tph2 (-/-) but not of SERT(-/-) mice. Our results emphasize the interaction between serotonin signaling and BDNF. Complete lack of brain serotonin induces BDNF expression.

  20. Integration of Genome-Wide Computation DRE Search, AhR ChIP-chip and Gene Expression Analyses of TCDD-Elicited Responses in the Mouse Liver

    PubMed Central

    2011-01-01

    Background The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor (TF) that mediates responses to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Integration of TCDD-induced genome-wide AhR enrichment, differential gene expression and computational dioxin response element (DRE) analyses further elucidate the hepatic AhR regulatory network. Results Global ChIP-chip and gene expression analyses were performed on hepatic tissue from immature ovariectomized mice orally gavaged with 30 μg/kg TCDD. ChIP-chip analysis identified 14,446 and 974 AhR enriched regions (1% false discovery rate) at 2 and 24 hrs, respectively. Enrichment density was greatest in the proximal promoter, and more specifically, within ± 1.5 kb of a transcriptional start site (TSS). AhR enrichment also occurred distal to a TSS (e.g. intergenic DNA and 3' UTR), extending the potential gene expression regulatory roles of the AhR. Although TF binding site analyses identified over-represented DRE sequences within enriched regions, approximately 50% of all AhR enriched regions lacked a DRE core (5'-GCGTG-3'). Microarray analysis identified 1,896 number of TCDD-responsive genes (|fold change| ≥ 1.5, P1(t) > 0.999). Integrating this gene expression data with our ChIP-chip and DRE analyses only identified 625 differentially expressed genes that involved an AhR interaction at a DRE. Functional annotation analysis of differentially regulated genes associated with AhR enrichment identified overrepresented processes related to fatty acid and lipid metabolism and transport, and xenobiotic metabolism, which are consistent with TCDD-elicited steatosis in the mouse liver. Conclusions Details of the AhR regulatory network have been expanded to include AhR-DNA interactions within intragenic and intergenic genomic regions. Moreover, the AhR can interact with DNA independent of a DRE core suggesting there are alternative mechanisms of AhR-mediated gene regulation. PMID:21762485

  1. Persistence of platelet thrombus formation in arterioles of mice lacking both von Willebrand factor and fibrinogen

    PubMed Central

    Ni, Heyu; Denis, Cécile V.; Subbarao, Sangeetha; Degen, Jay L.; Sato, Thomas N.; Hynes, Richard O.; Wagner, Denisa D.

    2000-01-01

    We used intravital microscopy to observe the formation of platelet plugs in ferric chloride–injured arterioles of live mice. With this model, we evaluated thrombus growth in mice lacking von Willebrand factor (vWF) and fibrinogen (Fg), the two key ligands known to mediate platelet adhesion and aggregation. In vWF–/– mice, despite the presence of arterial shear, delayed platelet adhesion occurred and stable thrombi formed. In many mice, a persisting high-shear channel never occluded. Abundant thrombi formed in Fg–/– mice, but they detached from the subendothelium, which ultimately caused downstream occlusion in all cases. Surprisingly, mice deficient in both vWF and Fg successfully formed thrombi with properties characteristic of both mutations, leading to vessel occlusion in the majority of vessels. Platelets of these doubly deficient mice specifically accumulated fibronectin in their α-granules, suggesting that fibronectin could be the ligand supporting the platelet aggregation. PMID:10930441

  2. Bone architecture and disc degeneration in the lumbar spine of mice lacking GDF-8 (myostatin).

    PubMed

    Hamrick, Mark W; Pennington, Catherine; Byron, Craig D

    2003-11-01

    GDF-8, also known as myostatin, is a member of the transforming growth factor-beta superfamily of secreted growth and differentiation factors that is expressed in vertebrate skeletal muscle. Myostatin functions as a negative regulator of skeletal muscle growth and myostatin null mice show a doubling of muscle mass compared to normal mice. We describe here morphology of the lumbar spine in myostatin knockout (Mstn(-/-)) mice using histological and densitometric techniques. The Mstn(-/-) mice examined in this study weigh approximately 10% more than controls (p<0.001) but the iliopsoas muscle is over 50% larger in the knockout mice than in wild-type mice (p<0.001). Peripheral quantitative computed tomography (pQCT) data from the fifth lumbar vertebra show that mice lacking myostatin have approximately 50% greater trabecular bone mineral density (p=0.001) and significantly greater cortical bone mineral content than normal mice. Toluidine blue staining of the intervertebral disc between L4-L5 reveals loss of proteoglycan staining in the hyaline end plates and inner annulus fibrosus of the knockout mice. Loss of cartilage staining in the caudal end plate of L4 is due to ossification of the end plate in the myostatin-deficient animals. Results from this study suggest that increased muscle mass in mice lacking myostatin is associated with increased bone mass as well as degenerative changes in the intervertebral disc.

  3. Increased response to morphine in mice lacking protein kinase C epsilon

    PubMed Central

    Newton, P. M.; Kim, J. A.; McGeehan, A. J.; Paredes, J. P.; Chu, K.; Wallace, M. J.; Roberts, A. J.; Hodge, C. W.; Messing, R. O.

    2014-01-01

    The protein kinase C (PKC) family of serine–threonine kinases has been implicated in behavioral responses to opiates, but little is known about the individual PKC isozymes involved. Here, we show that mice lacking PKCε have increased sensitivity to the rewarding effects of morphine, revealed as the expression of place preference and intravenous self-administration at very low doses of morphine that do not evoke place preference or self-administration in wild-type mice. The PKCε null mice also show prolonged maintenance of morphine place preference in response to repeated testing when compared with wild-type mice. The supraspinal analgesic effects of morphine are enhanced in PKCε null mice, and the development of tolerance to the spinal analgesic effects of morphine is delayed. The density of μ-opioid receptors and their coupling to G-proteins are normal. These studies identify PKCε as a key regulator of opiate sensitivity in mice. PMID:16899053

  4. Male and Female Mice Lacking Neuroligin-3 Modify the Behavior of Their Wild-Type Littermates.

    PubMed

    Kalbassi, Shireene; Bachmann, Sven O; Cross, Ellen; Roberton, Victoria H; Baudouin, Stéphane J

    2017-01-01

    In most mammals, including humans, the postnatal acquisition of normal social and nonsocial behavior critically depends on interactions with peers. Here we explore the possibility that mixed-group housing of mice carrying a deletion of Nlgn3, a gene associated with autism spectrum disorders, and their wild-type littermates induces changes in each other's behavior. We have found that, when raised together, male Nlgn3 knockout mice and their wild-type littermates displayed deficits in sociability. Moreover, social submission in adult male Nlgn3 knockout mice correlated with an increase in their anxiety. Re-expression of Nlgn3 in parvalbumin-expressing cells in transgenic animals rescued their social behavior and alleviated the phenotype of their wild-type littermates, further indicating that the social behavior of Nlgn3 knockout mice has a direct and measurable impact on wild-type animals' behavior. Finally, we showed that, unlike male mice, female mice lacking Nlgn3 were insensitive to their peers' behavior but modified the social behavior of their littermates. Altogether, our findings show that the environment is a critical factor in the development of behavioral phenotypes in transgenic and wild-type mice. In addition, these results reveal that the social environment has a sexually dimorphic effect on the behavior of mice lacking Nlgn3, being more influential in males than females.

  5. Mice lacking inducible nitric oxide synthase are not resistant to lipopolysaccharide-induced death.

    PubMed Central

    Laubach, V E; Shesely, E G; Smithies, O; Sherman, P A

    1995-01-01

    Nitric oxide produced by cytokine-inducible nitric oxide synthase (iNOS) is thought to be important in the pathogenesis of septic shock. To further our understanding of the role of iNOS in normal biology and in a variety of inflammatory disorders, including septic shock, we have used gene targeting to generate a mouse strain that lacks iNOS. Mice lacking iNOS were indistinguishable from wild-type mice in appearance and histology. Upon treatment with lipopolysaccharide and interferon gamma, peritoneal macrophages from the mutant mice did not produce nitric oxide measured as nitrite in the culture medium. In addition, lysates of these cells did not contain iNOS protein by immunoblot analysis or iNOS enzyme activity. In a Northern analysis of total RNA, no iNOS transcript of the correct size was detected. No increases in serum nitrite plus nitrate levels were observed in homozygous mutant mice treated with a lethal dose of lipopolysaccharide, but the mutant mice exhibited no significant survival advantage over wild-type mice. These results show that lack of iNOS activity does not prevent mortality in this murine model for septic shock. Images Fig. 2 Fig. 3 PMID:7479866

  6. Ahr function in lymphocytes: emerging concepts

    PubMed Central

    Zhou, Liang

    2015-01-01

    The aryl hydrocarbon receptor (Ahr) is an important regulator of the development and function of both innate and adaptive immune cells through roles associated with Ahr's ability to respond to cellular and dietary ligands. Recent findings have revealed tissue and context-specific functions for Ahr in both homeostasis and in during an immune response. I review these findings here, and integrate them into the current understanding of the mechanisms that regulate Ahr transcription and function. I propose a conceptual framework in which Ahr function is determined by three factors: the amount of Ahr in any given cell, the abundance and potency of Ahr ligands within certain tissues, and the tissue microenvironment wherein Ahr+ cells reside. This complexity emphasizes the necessity cell-type specific genetic approaches towards the study of Ahr function. PMID:26700314

  7. Phenotypes of mice lacking extracellular superoxide dismutase and copper- and zinc-containing superoxide dismutase.

    PubMed

    Sentman, Marie-Louise; Granström, Micael; Jakobson, Håkan; Reaume, Andrew; Basu, Samar; Marklund, Stefan L

    2006-03-17

    Mice lacking the secreted extracellular superoxide dismutase (EC-SOD) or the cytosolic copper- and zinc-containing SOD (CuZn-SOD) show relatively mild phenotypes. To explore the possibility that the isoenzymes have partly overlapping functions, single and double knockout mice were examined. The absence of EC-SOD was found to be without effect on the lifespan of mice, and the reduced lifespan of CuZn-SOD knockouts was not further shortened by EC-SOD deficiency. The urinary excretion of isoprostanes was increased in CuZn-SOD knockout mice, and plasma thiobarbituric acid-reactive substances levels were elevated in EC-SOD knockout mice. These oxidant stress markers showed potentiated increases in the absence of both isoenzymes. Other alterations were mainly found in CuZn-SOD knockout mice, such as halved glutathione peroxidase activity in the tissues examined and increased glutathione and iron in the liver. There were no changes in tissue content of the alternative superoxide scavenger ascorbate, but there was a 25% reduction in ascorbate in blood plasma in mice lacking CuZn-SOD. No increase was found in the urinary excretion of the terminal metabolites of NO, nitrite, and nitrate in any of the genotypes. In conclusion, apart from the increases in the global urinary and plasma oxidant stress markers, our phenotype studies revealed no other evidence that the copper- and zinc-containing SOD isoenzymes have overlapping roles.

  8. Lack of fibroblast growth factor 21 accelerates metabolic liver injury characterized by steatohepatities in mice

    PubMed Central

    Liu, Xingkai; Zhang, Ping; Martin, Robert C; Cui, Guozhen; Wang, Guangyi; Tan, Yi; Cai, Lu; Lv, Guoyue; Li, Yan

    2016-01-01

    Fibroblast growth factor 21 (FGF21) concentrations are increased in human subjects who either have type 2 diabetes or nonalcoholic fatty liver disease (NAFLD). While excessive fat in the liver promotes the release of pro-inflammatory cytokines, NAFLD progresses from steatosis to non alcoholic steatohepatitis (NASH), a more aggressive form of hepatic damage, and lastly toward cirrhosis and HCC. In our previous study, loss of FGF21 is associated with hyper-proliferation, aberrant p53, and HCC development in diabetes mice. In this study, we proposed to investigate the liver metabolic disorders by diabetes and the potential roles of FGF21 played in NASH and potential carcinogenetic transformation of HCC. NASH was induced in FGF21 knockout (FGF21KO) mice by streptozotocin administration or fed with high fat diet (HFD). The pathological transformation of steatohepatities as well as parameters of inflammation, lipid metabolism, cellular events, mesenchymal-epithelial transition (MET) and Wnt/β-catenin signaling was determined in the FGF21 KO diabetic mice and HFD fed mice. We found that mice lacking the FGF21 gene are more prone to develop NASH. A compromised microenvironment of NASH, which could facilitate the HCC carcinogenetic transformation, was found in FGF21 KO mice under metabolic disorders by diabetes and HFD feeding. This study provided further evidence that lack of FGF21 worsened the metabolic disorders in NASH and could render a tumor microenvironment for HCC initiation and progression in the liver of diabetes mice. PMID:27293995

  9. Characterization of the serum and liver proteomes in gut-microbiota-lacking mice.

    PubMed

    Tung, Yu-Tang; Chen, Ying-Ju; Chuang, Hsiao-Li; Huang, Wen-Ching; Lo, Chun-Tsung; Liao, Chen-Chung; Huang, Chi-Chang

    2017-01-01

    Current nutrition research is focusing on health promotion, disease prevention, and performance improvement for individuals and communities around the world. The humans with required nutritional ingredients depend on both how well the individual is provided with balanced foods and what state of gut microbiota the host has. Studying the mutually beneficial relationships between gut microbiome and host is an increasing attention in biomedical science. The purpose of this study is to understand the role of gut microbiota and to study interactions between gut microbiota and host. In this study, we used a shotgun proteomic approach to reveal the serum and liver proteomes in gut-microbiota-lacking mice. For serum, 15 and 8 proteins were uniquely detected in specific-pathogen-free (SPF) and germ-free (GF) mice, respectively, as well as the 3 and 20 proteins were significantly increased and decreased, respectively, in GF mice compared to SPF mice. Among the proteins of the serum, major urinary protein 1 (MUP-1) of GF mice was significantly decreased compared to SPF mice. In addition, MUP-1 expression is primarily regulated by testosterone. Lacking in gut flora has been implicated in many adverse effects, and now we have found its pathogenic root maybe gut bacteria can regulate the sex-hormone testosterone levels. In the liver, 8 and 22 proteins were uniquely detected in GF mice and SPF mice, respectively, as well as the 14 and 30 proteins were significantly increased and decreased, respectively, in GF mice compared to SPF mice. Furthermore, ingenuity pathway analysis (IPA) indicated that gut microbiota influence the host in cancer, organismal injury and abnormalities, respiratory disease; cell cycle, cellular movement and tissue development; cardiovascular disease, reproductive system disease; and lipid metabolism, molecular transport and small molecule biochemistry. Our findings provide more detailed information of the role of gut microbiota and will be useful to help

  10. Characterization of the serum and liver proteomes in gut-microbiota-lacking mice

    PubMed Central

    Tung, Yu-Tang; Chen, Ying-Ju; Chuang, Hsiao-Li; Huang, Wen-Ching; Lo, Chun-Tsung; Liao, Chen-Chung; Huang, Chi-Chang

    2017-01-01

    Current nutrition research is focusing on health promotion, disease prevention, and performance improvement for individuals and communities around the world. The humans with required nutritional ingredients depend on both how well the individual is provided with balanced foods and what state of gut microbiota the host has. Studying the mutually beneficial relationships between gut microbiome and host is an increasing attention in biomedical science. The purpose of this study is to understand the role of gut microbiota and to study interactions between gut microbiota and host. In this study, we used a shotgun proteomic approach to reveal the serum and liver proteomes in gut-microbiota-lacking mice. For serum, 15 and 8 proteins were uniquely detected in specific-pathogen-free (SPF) and germ-free (GF) mice, respectively, as well as the 3 and 20 proteins were significantly increased and decreased, respectively, in GF mice compared to SPF mice. Among the proteins of the serum, major urinary protein 1 (MUP-1) of GF mice was significantly decreased compared to SPF mice. In addition, MUP-1 expression is primarily regulated by testosterone. Lacking in gut flora has been implicated in many adverse effects, and now we have found its pathogenic root maybe gut bacteria can regulate the sex-hormone testosterone levels. In the liver, 8 and 22 proteins were uniquely detected in GF mice and SPF mice, respectively, as well as the 14 and 30 proteins were significantly increased and decreased, respectively, in GF mice compared to SPF mice. Furthermore, ingenuity pathway analysis (IPA) indicated that gut microbiota influence the host in cancer, organismal injury and abnormalities, respiratory disease; cell cycle, cellular movement and tissue development; cardiovascular disease, reproductive system disease; and lipid metabolism, molecular transport and small molecule biochemistry. Our findings provide more detailed information of the role of gut microbiota and will be useful to help

  11. Regulatory interactions among three members of the vertebrate aryl hydrocarbon receptor family: AHR repressor, AHR1, and AHR2.

    PubMed

    Karchner, Sibel I; Franks, Diana G; Powell, Wade H; Hahn, Mark E

    2002-03-01

    The effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related compounds occur via the aryl hydrocarbon receptor (AHR), a member of the basic helix-loop-helix-Per-ARNT-Sim homology (bHLH-PAS) protein superfamily. A single AHR gene has been identified in mammals, whereas many fish species, including the Atlantic killifish (Fundulus heteroclitus) possess two distinct AHR genes (AHR1 and a novel form, AHR2). A mouse bHLH-PAS protein closely related to AHR and designated AHR repressor (AHRR) is induced by 3-methylcholanthrene and represses the transcriptional activity of the AHR. To determine whether AHRR is the mammalian ortholog of fish AHR2 and to investigate the mechanisms by which AHRR regulates AHR function, we cloned an AHRR ortholog in F. heteroclitus with high sequence identity to the mouse and human AHRRs. Killifish AHRR encodes a 680-residue protein with a predicted molecular mass of 75.2 kDa. We show that in vitro expressed AHRR proteins from human, mouse, and killifish all fail to bind [(3)H]TCDD or [(3)H]beta-naphthoflavone. In transient transfection experiments using a luciferase reporter gene under control of AHR response elements, killifish AHRR inhibited the TCDD-dependent transactivation function of both AHR1 and AHR2. AHRR mRNA is widely expressed in killifish tissues and is inducible by TCDD or polychlorinated biphenyls, but its expression is not altered in a population of fish exhibiting genetic resistance to these compounds. The F. heteroclitus AHRR promoter contains three putative AHR response elements. Both AHR1 and AHR2 activated transcription of luciferase driven by the AHRR promoter, and AHRR could repress its own promoter. Thus, AHRR is an evolutionarily conserved, TCDD-inducible repressor of AHR1 and AHR2 function. Phylogenetic analysis shows that AHRR, AHR1, and AHR2 are distinct genes, members of an AHR gene family; these three vertebrate AHR-like genes descended from a single invertebrate AHR.

  12. The aryl hydrocarbon receptor (AhR) inhibits vanadate-induced vascular endothelial growth factor (VEGF) production in TRAMP prostates

    PubMed Central

    Fritz, Wayne A.; Lin, Tien-Min; Peterson, Richard E.

    2008-01-01

    Hypoxia-inducible factor-1 alpha (HIF-1α) and aryl hydrocarbon receptor nuclear translocator (ARNT) are basic helix-loop-helix/per-arnt-sim (PAS) family transcription factors. During angiogenesis and tumor growth, HIF-1α dimerizes with ARNT, inducing expression of many genes, including vascular endothelial growth factor (VEGF). ARNT also dimerizes with the aryl hydrocarbon receptor (AhR). AhR-null (Ahr−/−) transgenic adenocarcinoma of the mouse prostate (TRAMP) mice develop prostate tumors with greater frequency than AhR wild-type (Ahr+/+) TRAMP mice, even though prevalence of prostate epithelial hyperplasia is not inhibited. This suggests that Ahr inhibits prostate carcinogenesis. In TRAMP mice, prostatic epithelial hyperplasia results in stabilized HIF-1α, inducing expression of VEGF, a prerequisite for tumor growth and angiogenesis. Since ARNT is a common dimerization partner of AhR and HIF-1α, we hypothesized that the AhR inhibits prostate tumor formation by competing with HIF-1α for ARNT, thereby limiting VEGF production. Prostates from Ahr+/+, Ahr+/− and Ahr−/− C57BL/6J TRAMP mice were cultured in the presence of graded concentrations of vanadate, an inducer of VEGF through the HIF-1α–ARNT pathway. Vanadate induced VEGF protein in a dose-dependent fashion in Ahr+/− and Ahr−/− TRAMP cultures, but not in Ahr+/+ cultures. However, vanadate induced upstream proteins in the phosphatidylinositol 3-kinase-signaling cascade to a similar extent in TRAMPs of each Ahr genotype, evidenced by v-akt murine thymoma viral oncogene homolog (Akt) phosphorylation. These findings suggest that AhR sequesters ARNT, decreasing interaction with HIF-1α reducing VEGF production. Since VEGF is required for tumor vascularization and growth, these studies further suggest that reduction in VEGF correlates with inhibited prostate carcinogenesis in Ahr+/+ TRAMP mice. PMID:18359762

  13. Hypoxia transduction by carotid body chemoreceptors in mice lacking dopamine D(2) receptors.

    PubMed

    Prieto-Lloret, J; Donnelly, D F; Rico, A J; Moratalla, R; González, C; Rigual, R J

    2007-10-01

    Hypoxia-induced dopamine (DA) release from carotid body (CB) glomus cells and activation of postsynaptic D(2) receptors have been proposed to play an important role in the neurotransmission process between the glomus cells and afferent nerve endings. To better resolve the role of D(2) receptors, we examined afferent nerve activity, catecholamine content and release, and ventilation of genetically engineered mice lacking D(2) receptors (D(2)(-/-) mice). Single-unit afferent nerve activities of D(2)(-/-) mice in vitro were significantly reduced by 45% and 25% compared with wild-type (WT) mice during superfusion with saline equilibrated with mild hypoxia (Po(2) approximately 50 Torr) or severe hypoxia (Po(2) approximately 20 Torr), respectively. Catecholamine release in D(2)(-/-) mice was enhanced by 125% in mild hypoxia and 75% in severe hypoxia compared with WT mice, and the rate of rise was increased in D(2)(-/-) mice. We conclude that CB transduction of hypoxia is still present in D(2)(-/-) mice, but the response magnitude is reduced. However, the ventilatory response to acute hypoxia is maintained, perhaps because of an enhanced processing of chemoreceptor input by brain stem respiratory nuclei.

  14. Mice lacking the gamma interferon receptor have an impaired granulomatous reaction to Schistosoma mansoni infection.

    PubMed Central

    Rezende, S A; Oliveira, V R; Silva, A M; Alves, J B; Goes, A M; Reis, L F

    1997-01-01

    The egg-induced granulomatous reaction in Schistosoma mansoni-infected individuals develops within the portal system of the liver and is the major pathological finding in schistosomiasis. We have infected mice lacking the gamma interferon (IFN-gamma) receptor with S. mansoni larvae and studied the development of hepatic granulomas in these mutant mice in comparison to that in control wild-type mice. In the absence of IFN-gamma activity, a dramatic reduction in the size and architecture of the granuloma was observed. Granulomas from mutant mice were smaller than those from the control group and showed a significant reduction in the number of infiltrating inflammatory cells. Moreover, they appear to prematurely progress to the chronic phase of the reaction at a time when the control group still has acute inflammation. Our data suggests a pivotal role for IFN-gamma in the early events of the granulomatous reaction in vivo. PMID:9234812

  15. Altered cognitive performance and synaptic function in the hippocampus of mice lacking C3.

    PubMed

    Perez-Alcazar, Marta; Daborg, Jonny; Stokowska, Anna; Wasling, Pontus; Björefeldt, Andreas; Kalm, Marie; Zetterberg, Henrik; Carlström, Karl E; Blomgren, Klas; Ekdahl, Christine T; Hanse, Eric; Pekna, Marcela

    2014-03-01

    Previous work implicated the complement system in adult neurogenesis as well as elimination of synapses in the developing and injured CNS. In the present study, we used mice lacking the third complement component (C3) to elucidate the role the complement system plays in hippocampus-dependent learning and synaptic function. We found that the constitutive absence of C3 is associated with enhanced place and reversal learning in adult mice. Our findings of lower release probability at CA3-CA1 glutamatergic synapses in combination with unaltered overall efficacy of these synapses in C3 deficient mice implicate C3 as a negative regulator of the number of functional glutamatergic synapses in the hippocampus. The C3 deficient mice showed no signs of spontaneous epileptiform activity in the hippocampus. We conclude that C3 plays a role in the regulation of the number and function of glutamatergic synapses in the hippocampus and exerts negative effects on hippocampus-dependent cognitive performance.

  16. EGF AND TGF ALPHA EXPRESSION INFLUENCE THE DEVELOPMENTAL TOXICITY OF TCDD: DOSE RESPONSE AND AHR PHENOTYPE IN EGF, TGF ALPHA AND EGF+TGF ALPHA KNOCKOUT MICE

    EPA Science Inventory

    Abstract
    The environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) produces cleft palate (CP) and hydronephrosis (HN) in mice. The etiology of these defects involves hyperproliferation of epithelial cells of the secondary palatal shelf and ureter, respectively. ...

  17. EGF AND TGF ALPHA EXPRESSION INFLUENCE THE DEVELOPMENTAL TOXICITY OF TCDD: DOSE RESPONSE AND AHR PHENOTYPE IN EGF, TGF ALPHA AND EGF+TGF ALPHA KNOCKOUT MICE

    EPA Science Inventory

    Abstract
    The environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) produces cleft palate (CP) and hydronephrosis (HN) in mice. The etiology of these defects involves hyperproliferation of epithelial cells of the secondary palatal shelf and ureter, respectively. ...

  18. Mice lacking Mrp1 have reduced testicular steroid hormone levels and alterations in steroid biosynthetic enzymes

    PubMed Central

    SIVILS, JEFFREY C.; GONZALEZ, IVEN; BAIN, LISA J.

    2010-01-01

    The multidrug resistance-associated protein 1 (MRP1/ABCC1) is a member of the ABC active transporter family that can transport several steroid hormone conjugates, including 17β-estradiol glucuronide, dehydroepiandrosterone sulfate (DHEAS), and estrone 3-sulfate. The present study investigated the role that MRP1 plays in maintaining proper hormone levels in the serum and testes. Serum and testicular steroid hormone levels were examined in both wild-type mice and Mrp1 null mice. Serum testosterone levels were reduced 5-fold in mice lacking Mrp1, while testicular androstenedione, testosterone, estradiol, and dehydroepiandrosterone (DHEA) were significantly reduced by 1.7- to 4.5-fold in Mrp1 knockout mice. Investigating the mechanisms responsible for the reduction in steroid hormones in Mrp1-/- mice revealed no differences in the expression or activity of enzymes that inactivate steroids, the sulfotransferases or glucuronosyltransferases. However, steroid biosynthetic enzyme levels in the testes were altered. Cyp17 protein levels were increased by 1.6-fold, while Cyp17 activity using progesterone as a substrate was also increased by 1.4-2.0-fold in mice lacking Mrp1. Additionally, the ratio of 17β-hydroxysteroid dehydrogenase to 3β-hydroxysteroid dehydrogenase, and steroidogenic factor 1 to 3βhydroxysteroid dehydrogenase were significantly increased in the testes of Mrp1-/- mice. These results indicate that Mrp1-/- mice have lowered steroid hormones levels, and suggests that upregulation of steroid biosynthetic enzymes may be an attempt to maintain proper steroid hormone homeostasis. PMID:20178799

  19. Increased consumption of ethanol and sugar water in mice lacking the dopamine D2 long receptor

    PubMed Central

    Bulwa, Zachary B.; Sharlin, Jordan A.; Clark, Peter J.; Bhattacharya, Tushar K.; Kilby, Chessa N.; Wang, Yanyan; Rhodes, Justin S.

    2011-01-01

    Individual differences in dopamine D2 receptor (D2R) expression in the brain are thought to influence motivation and reinforcement for ethanol and other rewards. D2R exists in two isoforms, D2 long (D2LR) and D2 short (D2SR), produced by alternative splicing of the same gene. The relative contributions of D2LR versus D2SR to ethanol and sugar water drinking are not known. Genetic engineering was used to produce a line of knockout (KO) mice that lack D2LR and consequently have increased expression of D2SR. KO and wild-type (WT) mice of both sexes were tested for intake of 20% ethanol, 10% sugar water and plain tap water using established drinking-in-the-dark procedures. Mice were also tested for effects of the D2 antagonist eticlopride on intake of ethanol to determine whether KO responses were caused by lack of D2LR or over-representation of D2SR. Locomotor activity on running wheels and in cages without wheels was also measured for comparison. D2L KO mice drank significantly more ethanol than WT in both sexes. KO mice drank more sugar water than WT in females but not in males. Eticlopride dose- dependently decreased ethanol intake in all groups except male KO. KO mice were less physically active than WT in cages with or without running wheels. Results suggest that over-representation of D2SR contributes to increased intake of ethanol in the KO mice. Decreasing wheel running and general levels of physical activity in the KO mice rules out the possibility that higher intake results from higher motor activity. Results extend the literature implicating altered expression of D2R in risk for addiction by delineating the contribution of individual D2R isoforms. These findings suggest that D2LR and D2SR play differential roles in consumption of alcohol and sugar rewards. PMID:21803530

  20. Increased consumption of ethanol and sugar water in mice lacking the dopamine D2 long receptor.

    PubMed

    Bulwa, Zachary B; Sharlin, Jordan A; Clark, Peter J; Bhattacharya, Tushar K; Kilby, Chessa N; Wang, Yanyan; Rhodes, Justin S

    2011-11-01

    Individual differences in dopamine D2 receptor (D2R) expression in the brain are thought to influence motivation and reinforcement for ethanol and other rewards. D2R exists in two isoforms, D2 long (D2LR) and D2 short (D2SR), produced by alternative splicing of the same gene. The relative contributions of D2LR versus D2SR to ethanol and sugar water drinking are not known. Genetic engineering was used to produce a line of knockout (KO) mice that lack D2LR and consequently have increased expression of D2SR. KO and wild-type (WT) mice of both sexes were tested for intake of 20% ethanol, 10% sugar water and plain tap water using established drinking-in-the-dark procedures. Mice were also tested for effects of the D2 antagonist eticlopride on intake of ethanol to determine whether KO responses were caused by lack of D2LR or overrepresentation of D2SR. Locomotor activity on running wheels and in cages without wheels was also measured for comparison. D2L KO mice drank significantly more ethanol than WT in both sexes. KO mice drank more sugar water than WT in females but not in males. Eticlopride dose dependently decreased ethanol intake in all groups except male KO. KO mice were less physically active than WT in cages with or without running wheels. Results suggest that overrepresentation of D2SR contributes to increased intake of ethanol in the KO mice. Decreasing wheel running and general levels of physical activity in the KO mice rules out the possibility that higher intake results from higher motor activity. Results extend the literature implicating altered expression of D2R in risk for addiction by delineating the contribution of individual D2R isoforms. These findings suggest that D2LR and D2SR play differential roles in consumption of alcohol and sugar rewards.

  1. Mice lacking components of adaptive immunity show increased Brucella abortus virB mutant colonization.

    PubMed

    Rolán, Hortensia García; Tsolis, Renée M

    2007-06-01

    The Brucella abortus type IV secretion system (T4SS), encoded by the virB genes, is essential for survival in mononuclear phagocytes in vitro. In the mouse model, a B. abortus virB mutant was initially able to colonize the spleen at the level of the wild type for approximately 3 to 5 days, which coincided with the development of adaptive immunity. To investigate the relationship between survival in macrophages cultivated in vitro and persistence in tissues in vivo, we tested the ability of mutant mice lacking components of adaptive immunity to eliminate the virB mutant from the spleen during a mixed infection with the B. abortus wild type. Ifng(-/-) or beta(2)m(-/-) mice were able to clear the virB mutant to the same degree as control mice. However, spleens of Rag1(-/-) mice and Igh6(-/-) mice were more highly colonized by the virB mutant than control mice after 14 to 21 days, suggesting that, in these mice, there is not an absolute requirement for the T4SS to mediate persistence of B. abortus in the spleen. Macrophages isolated from Igh6(-/-) mice killed the virB mutant to the same extent as macrophages from control mice, showing that the reduced ability of these mice to clear the virB mutant from the spleen does not correlate with diminished macrophage function in vitro. These results show that in the murine model host, the T4SS is required for persistence beyond 3 to 5 days after infection and suggest that the T4SS may contribute to evasion of adaptive immune mechanisms by B. abortus.

  2. Prevention of obesity and insulin resistance in mice lacking plasminogen activator inhibitor 1.

    PubMed

    Ma, Li-Jun; Mao, Su-Li; Taylor, Kevin L; Kanjanabuch, Talerngsak; Guan, YouFei; Zhang, YaHua; Brown, Nancy J; Swift, Larry L; McGuinness, Owen P; Wasserman, David H; Vaughan, Douglas E; Fogo, Agnes B

    2004-02-01

    Increased plasminogen activator inhibitor 1 (PAI-1) has been linked to not only thrombosis and fibrosis but also to obesity and insulin resistance. Increased PAI-1 levels have been presumed to be consequent to obesity. We investigated the interrelationships of PAI-1, obesity, and insulin resistance in a high-fat/high-carbohydrate (HF) diet-induced obesity model in wild-type (WT) and PAI-1-deficient mice (PAI-1(-/-)). Obesity and insulin resistance developing in WT mice on an HF diet were completely prevented in mice lacking PAI-1. PAI-1(-/-) mice on an HF diet had increased resting metabolic rates and total energy expenditure compared with WT mice, along with a marked increase in uncoupling protein 3 mRNA expression in skeletal muscle, likely mechanisms contributing to the prevention of obesity. In addition, insulin sensitivity was enhanced significantly in PAI-1(-/-) mice on an HF diet, as shown by euglycemic-hyperinsulinemic clamp studies. Peroxisome proliferator-activated receptor (PPAR)-gamma and adiponectin mRNA, key control molecules in lipid metabolism and insulin sensitivity, were maintained in response to an HF diet in white adipose tissue in PAI-1(-/-) mice, contrasting with downregulation in WT mice. This maintenance of PPAR-gamma and adiponectin may also contribute to the observed maintenance of body weight and insulin sensitivity in PAI-1(-/-) mice. Treatment in WT mice on an HF diet with the angiotensin type 1 receptor antagonist to downregulate PAI-1 indeed inhibited PAI-1 increases and ameliorated diet-induced obesity, hyperglycemia, and hyperinsulinemia. PAI-1 deficiency also enhanced basal and insulin-stimulated glucose uptake in adipose cells in vitro. Our data suggest that PAI-1 may not merely increase in response to obesity and insulin resistance, but may have a direct causal role in obesity and insulin resistance. Inhibition of PAI-1 might provide a novel anti-obesity and anti-insulin resistance treatment.

  3. The aryl hydrocarbon receptor AhR links atopic dermatitis and air pollution via induction of the neurotrophic factor artemin.

    PubMed

    Hidaka, Takanori; Ogawa, Eisaku; Kobayashi, Eri H; Suzuki, Takafumi; Funayama, Ryo; Nagashima, Takeshi; Fujimura, Taku; Aiba, Setsuya; Nakayama, Keiko; Okuyama, Ryuhei; Yamamoto, Masayuki

    2017-01-01

    Atopic dermatitis is increasing worldwide in correlation with air pollution. Various organic components of pollutants activate the transcription factor AhR (aryl hydrocarbon receptor). Through the use of AhR-CA mice, whose keratinocytes express constitutively active AhR and that develop atopic-dermatitis-like phenotypes, we identified Artn as a keratinocyte-specific AhR target gene whose product (the neurotrophic factor artemin) was responsible for epidermal hyper-innervation that led to hypersensitivity to pruritus. The activation of AhR via air pollutants induced expression of artemin, alloknesis, epidermal hyper-innervation and inflammation. AhR activation and ARTN expression were positively correlated in the epidermis of patients with atopic dermatitis. Thus, AhR in keratinocytes senses environmental stimuli and elicits an atopic-dermatitis pathology. We propose a mechanism of air-pollution-induced atopic dermatitis via activation of AhR.

  4. Impaired ventilatory acclimatization to hypoxia in mice lacking the immediate early gene fos B.

    PubMed

    Malik, Mohammad T; Peng, Ying-Jie; Kline, David D; Adhikary, Gautam; Prabhakar, Nanduri R

    2005-01-15

    Earlier studies on cell culture models suggested that immediate early genes (IEGs) play an important role in cellular adaptations to hypoxia. Whether IEGs are also necessary for hypoxic adaptations in intact animals is not known. In the present study we examined the potential importance of fos B, an IEG in ventilatory acclimatization to hypoxia. Experiments were performed on wild type and mutant mice lacking the fos B gene. Ventilation was monitored by whole body plethysmography in awake animals. Baseline ventilation under normoxia, and ventilatory response to acute hypoxia and hypercapnia were comparable between wild type and mutant mice. Hypobaric hypoxia (0.4 atm; 3 days) resulted in a significant elevation of baseline ventilation in wild type but not in mutant mice. Wild type mice exposed to hypobaric hypoxia manifested an enhanced hypoxic ventilatory response compared to pre-hypobaric hypoxia. In contrast, hypobaric hypoxia had no effect on the hypoxic ventilatory response in mutant mice. Hypercapnic ventilatory responses, however, were unaffected by hypobaric hypoxia in both groups of mice. These results suggest that the fos B, an immediate early gene, plays an important role in ventilatory acclimatization to hypoxia in mice.

  5. Reduced hypertension-induced end-organ damage in mice lacking cardiac and renal angiotensinogen synthesis.

    PubMed

    Kang, Ningling; Walther, Thomas; Tian, Xiao-Li; Bohlender, Jürgen; Fukamizu, Akiyoshi; Ganten, Detlev; Bader, Michael

    2002-06-01

    Hypertension-induced damage of kidney and heart is of major clinical relevance, but its pathophysiology is only partially understood. As there is considerable evidence for involvement of angiotensin II, we generated a new mouse model by breeding angiotensinogen (AOGEN) deficient mice with transgenic animals expressing the rat AOGEN gene only in brain and liver. This genetic manipulation overcame the hypotension of AOGEN-deficient mice and even caused hypertension indistinguishable in its extent from the parent transgenic mice with an intact endogenous AOGEN gene. In contrast to normal mice, however, crossbred animals lacked detectable expression of AOGEN in kidney and heart. As a consequence they showed markedly reduced cardiac hypertrophy and fibrosis. Furthermore, hypertension-induced alterations in kidney histology and function were less pronounced in crossbred mice than in equally hypertensive animals expressing AOGEN locally. The dysmorphogenesis observed in kidneys from AOGEN-deficient mice was absent in mice expressing this gene only in liver and brain. Our results support an important role of local AOGEN expression in hypertension-induced end-organ damage but not in the development of the kidney.

  6. Dietary fructose-induced hepatocellular carcinoma development manifested in mice lacking apoptosis inhibitor of macrophage (AIM).

    PubMed

    Ozawa, Takayuki; Maehara, Natsumi; Kai, Toshihiro; Arai, Satoko; Miyazaki, Toru

    2016-12-01

    The consumption of fructose, including the use of high-fructose corn syrup as a sweetener, has increased continuously in recent decades. Although the involvement of fructose in the development of metabolic diseases has been emphasized recently, whether fructose intake increases susceptibility to steatosis-associated hepatocellular carcinoma (HCC) is unclear. Here, we investigated this issue using mice lacking a circulating protein, apoptosis inhibitor of macrophage (AIM, encoded by cd5l). AIM does not induce carcinogenesis of hepatocytes, but provokes necrotic death specifically in AIM-bound cancer cells through complement cascade activation, thereby preventing HCC tumor development in wild-type mice. When subjected to a high-fructose diet (HFrD), AIM-deficient (AIM(-/-) ) mice showed liver steatosis and subsequent liver inflammation as well as fibrosis, but at much milder levels compared with mice fed a high-fat diet. However, AIM(-/-) mice were markedly susceptible to HCC tumor development, whereas no wild-type mice developed the disease. Systemic metabolic states, including obesity and insulin resistance, were similar in both types of mice after HFrD challenge, indicating no influence of AIM on HFrD-induced metabolic changes. Our results suggest that dietary fructose increases the risk for liver carcinogenesis and that individuals with low blood AIM levels may be susceptible to HCC under chronic fructose intake. © 2016 The Authors. Genes to Cells published by Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.

  7. B cell development in mice that lack one or both immunoglobulin kappa light chain genes.

    PubMed Central

    Chen, J; Trounstine, M; Kurahara, C; Young, F; Kuo, C C; Xu, Y; Loring, J F; Alt, F W; Huszar, D

    1993-01-01

    We have generated mice that lack the ability to produce immunoglobulin (Ig) kappa light chains by targeted deletion of J kappa and C kappa gene segments and the intervening sequences in mouse embryonic stem cells. In wild type mice, approximately 95% of B cells express kappa light chains and only approximately 5% express lambda light chains. Mice heterozygous for the J kappa C kappa deletion have approximately 2-fold more lambda+ B cells than wild-type littermates. Compared with normal mice, homozygous mutants for the J kappa C kappa deletion have about half the number of B cells in both the newly generated and the peripheral B cell compartments, and all of these B cells express lambda light chains in their Ig. Therefore, homozygous mutant mice appear to produce lambda-expressing cells at nearly 10 times the rate observed in normal mice. These findings demonstrate that kappa gene assembly and/or expression is not a prerequisite for lambda gene assembly and expression. Furthermore, there is no detectable rearrangement of 3' kappa RS sequences in lambda+ B cells of the homozygous mutant mice, thus rearrangements of these sequences, per se, is not required for lambda light chain gene assembly. We discuss these findings in the context of their implications for the control of Ig light chain gene rearrangement and potential applications of the mutant animals. Images PMID:8458340

  8. Myogenic stem cell function is impaired in mice lacking the forkhead/winged helix protein MNF.

    PubMed

    Garry, D J; Meeson, A; Elterman, J; Zhao, Y; Yang, P; Bassel-Duby, R; Williams, R S

    2000-05-09

    Myocyte nuclear factor (MNF) is a winged helix transcription factor that is expressed selectively in myogenic stem cells (satellite cells) of adult animals. Using a gene knockout strategy to generate a functional null allele at the Mnf locus, we observed that mice lacking MNF are viable, but severely runted. Skeletal muscles of Mnf-/- animals are atrophic, and satellite cell function is impaired. Muscle regeneration after injury is delayed and incomplete, and the normal timing of expression of cell cycle regulators and myogenic determination genes is dysregulated. Mnf mutant mice were intercrossed with mdx mice that lack dystrophin and exhibit only a subtle myopathic phenotype. In contrast, mdx mice that also lack MNF die in the first few weeks of life with a severe myopathy. Haploinsufficiency at the Mnf locus (Mnf+/-) also exacerbates the mdx phenotype to more closely resemble Duchenne's muscular dystrophy in humans. We conclude that MNF acts to regulate genes that coordinate the proliferation and differentiation of myogenic stem cells after muscle injury. Animals deficient in MNF may prove useful for evaluation of potential therapeutic interventions to promote muscle regeneration for patients having Duchenne's muscular dystrophy.

  9. B7-dependent T-cell costimulation in mice lacking CD28 and CTLA4

    PubMed Central

    Mandelbrot, Didier A.; Oosterwegel, Mariette A.; Shimizu, Koichi; Yamada, Akira; Freeman, Gordon J.; Mitchell, Richard N.; Sayegh, Mohammed H.; Sharpe, Arlene H.

    2001-01-01

    To examine whether B7 costimulation can be mediated by a molecule on T cells that is neither CD28 nor CTLA4, we generated mice lacking both of these receptors. CD28/CTLA4–/– mice resemble CD28–/– mice in having decreased expression of T-cell activation markers in vivo and decreased T-cell proliferation in vitro, as compared with wild-type mice. Using multiple approaches, we find B7-dependent costimulation in CD28/CTLA4–/– mice. The proliferation of CD28/CTLA4–/– T cells is inhibited by CTLA4-Ig and by the use of antigen-presenting cells lacking both B7-1 and B7-2. CD28/CTLA4–/– T-cell proliferation is increased by exposure to Chinese hamster ovary cells transfected with B7-1 or B7-2. Finally, administration of CTLA4-Ig to CD28/CTLA4–/– cardiac allograft recipients significantly prolongs graft survival. These data support the existence of an additional receptor for B7 molecules that is neither CD28 nor CTLA4. PMID:11285307

  10. Mice lacking the galanin gene show decreased sensitivity to nicotine conditioned place preference.

    PubMed

    Neugebauer, Nichole M; Henehan, Robert M; Hales, Claire A; Picciotto, Marina R

    2011-03-01

    Previous work has indicated that the neuropeptide galanin decreases sensitivity to the rewarding effects of morphine and cocaine, but increases alcohol drinking. The aim of the current study was to examine the role of galanin signaling in nicotine reward by testing the effects of nicotine in mice lacking galanin peptide (GAL-/-) as compared to wild-type (GAL+/+) controls. Using an unbiased, three-chamber conditioned place preference (CPP) paradigm the dose-response function for nicotine CPP was tested in GAL-/- and GAL+/+ mice. Since activation of extracellular signal-related kinase (ERK2) is involved in the rewarding effects of several classes of drugs of abuse, we then measured the level of ERK2 phosphorylation in the nucleus accumbens shell (NACsh) and core (NACco) of GAL-/- and GAL+/+ mice following re-exposure to the CPP chamber previously paired with nicotine as a marker of mesolimbic system activation. Finally, we examined whether acute nicotine administration affects ERK2 activity in GAL-/- and GAL+/+ mice. GAL-/- mice required a higher dose of nicotine to induce a significant CPP compared to GAL+/+ mice. In the conditioning groups showing significant expression of nicotine CPP, only GAL+/+ mice showed ERK2 activation in the NACsh. This suggests that the nicotine CPP observed in GAL+/+ mice resulted in differential recruitment of ERK signaling in the NACsh compared to GAL-/- mice. In addition, no activation of ERK2 was observed following acute nicotine administration in either genotype. These data, along with prior results, suggest that galanin alters sensitivity to drugs of abuse differentially, with morphine, cocaine and amphetamine place preference suppressed, and nicotine and alcohol preference increased, by galanin signaling.

  11. Mice lacking δ-opioid receptors resist the development of diet-induced obesity

    PubMed Central

    Czyzyk, Traci A.; Romero-Picó, Amparo; Pintar, John; McKinzie, Jaime H.; Tschöp, Matthias H.; Statnick, Michael A.; Nogueiras, Ruben

    2012-01-01

    Pharmacological manipulation of opioid receptors alters feeding behavior. However, the individual contributions of each opioid receptor subtype on energy balance remain largely unknown. Herein, we investigated whether genetic disruption of the δ-opioid receptor (DOR) also controls energy homeostasis. Mice lacking DOR and wild-type mice were fed with standard diet and high-energy diet (HED). Mice were analyzed in vivo with the indirect calorimetry system, and tissues were analyzed by real-time PCR and Western blot analysis. DOR-knockout (KO) mice gained less weight (P<0.01) and had lower fat mass (P<0.01) when compared to WT mice fed an HED. Although DOR-KO mice were hyperphagic, they showed higher energy expenditure (P<0.05), which was the result of an increased activation of the thermogenic program in brown adipose tissue. The increased nonshivering thermogenesis involved the stimulation of uncoupling protein 1 (UCP1; P<0.01), peroxisome proliferator-activated receptor γ coactivator (PGC1α; P<0.05), and fibroblast growth factor 21 (FGF21; P<0.01). DOR deficiency also led to an attenuation of triglyceride content in the liver (P<0.05) in response to an HED. These findings reveal a novel role of DOR in the control of thermogenic markers and energy expenditure, and they provide a potential new therapeutic approach for the treatment of obesity.—Czyzyk, T. A., Romero-Picó, A., Pintar, J., McKinzie, J. H., Tschöp, M. H., Statnick, M. A., Nogueiras, R. Mice lacking δ-opioid receptors resist the development of diet-induced obesity. PMID:22593549

  12. Remodeling of the cervix and parturition in mice lacking the progesterone receptor B isoform.

    PubMed

    Yellon, Steven M; Oshiro, Bryan T; Chhaya, Tejas Y; Lechuga, Thomas J; Dias, Rejane M; Burns, Alexandra E; Force, Lindsey; Apostolakis, Ede M

    2011-09-01

    Withdrawal of progestational support for pregnancy is part of the final common pathways for parturition, but the role of nuclear progesterone receptor (PGR) isoforms in this process is not known. To determine if the PGR-B isoform participates in cervical remodeling at term, cervices were obtained from mice lacking PGR-B (PGR-BKO) and from wild-type (WT) controls before or after birth. PGR-BKO mice gave birth to viable pups at the same time as WT controls during the early morning of Day 19 postbreeding. Morphological analyses indicated that by the day before birth, cervices from PGR-BKO and WT mice had increased in size, with fewer cell nuclei/area as well as diminished collagen content and structure, as evidenced by optical density of picrosirius red-stained sections, compared to cervices from nonpregnant mice. Moreover, increased numbers of resident macrophages, but not neutrophils, were found in the prepartum cervix of PGR-BKO compared to nonpregnant mice, parallel to findings in WT mice. These results suggest that PGR-B does not contribute to the growth or degradation of the extracellular matrix or proinflammatory processes associated with recruitment of macrophages in the cervix leading up to birth. Rather, other receptors may contribute to the progesterone-dependent mechanism that promotes remodeling of the cervix during pregnancy and in the proinflammatory process associated with ripening before parturition.

  13. Mice lacking the cerebral cortex develop normal song: insights into the foundations of vocal learning.

    PubMed

    Hammerschmidt, Kurt; Whelan, Gabriela; Eichele, Gregor; Fischer, Julia

    2015-03-06

    Mouse models play an increasingly important role in the identification and functional assessment of speech-associated genes, with a focus on genes involved in vocal production, and possibly vocal learning. Moreover, mice reportedly show direct projections from the cortex to brainstem vocal motor neurons, implying a degree of volitional control over vocal output. Yet, deaf mice did not reveal differences in call structures compared to their littermates, suggesting that auditory input is not a prerequisite for the development of species-specific sounds. To elucidate the importance of cortical structures for the development of mouse ultrasonic vocalizations (USVs) in more detail, we studied Emx1-CRE;Esco2(fl/fl) mice, which lack the hippocampus and large parts of the cortex. We conducted acoustic analyses of the USVs of 28 pups during short-term isolation and 23 adult males during courtship encounters. We found no significant differences in the vocalizations of Emx1-CRE;Esco2(fl/fl) mice, and only minor differences in call type usage in adult mice, compared to control littermates. Our findings question the notion that cortical structures are necessary for the production of mouse USVs. Thus, mice might be less suitable to study the mechanisms supporting vocal learning than previously assumed, despite their value for studying the genetic foundations of neurodevelopment more generally.

  14. Remodeling of the Cervix and Parturition in Mice Lacking the Progesterone Receptor B Isoform1

    PubMed Central

    Yellon, Steven M.; Oshiro, Bryan T.; Chhaya, Tejas Y.; Lechuga, Thomas J.; Dias, Rejane M.; Burns, Alexandra E.; Force, Lindsey; Apostolakis, Ede M.

    2011-01-01

    Withdrawal of progestational support for pregnancy is part of the final common pathways for parturition, but the role of nuclear progesterone receptor (PGR) isoforms in this process is not known. To determine if the PGR-B isoform participates in cervical remodeling at term, cervices were obtained from mice lacking PGR-B (PGR-BKO) and from wild-type (WT) controls before or after birth. PGR-BKO mice gave birth to viable pups at the same time as WT controls during the early morning of Day 19 postbreeding. Morphological analyses indicated that by the day before birth, cervices from PGR-BKO and WT mice had increased in size, with fewer cell nuclei/area as well as diminished collagen content and structure, as evidenced by optical density of picrosirius red-stained sections, compared to cervices from nonpregnant mice. Moreover, increased numbers of resident macrophages, but not neutrophils, were found in the prepartum cervix of PGR-BKO compared to nonpregnant mice, parallel to findings in WT mice. These results suggest that PGR-B does not contribute to the growth or degradation of the extracellular matrix or proinflammatory processes associated with recruitment of macrophages in the cervix leading up to birth. Rather, other receptors may contribute to the progesterone-dependent mechanism that promotes remodeling of the cervix during pregnancy and in the proinflammatory process associated with ripening before parturition. PMID:21613631

  15. Impaired locomotor activity and exploratory behavior in mice lacking histamine H1 receptors

    PubMed Central

    Inoue, Isao; Yanai, Kazuhiko; Kitamura, Daisuke; Taniuchi, Ichiro; Kobayashi, Takashi; Niimura, Kaku; Watanabe, Takehiko; Watanabe, Takeshi

    1996-01-01

    From pharmacological studies using histamine antagonists and agonists, it has been demonstrated that histamine modulates many physiological functions of the hypothalamus, such as arousal state, locomotor activity, feeding, and drinking. Three kinds of receptors (H1, H2, and H3) mediate these actions. To define the contribution of the histamine H1 receptors (H1R) to behavior, mutant mice lacking the H1R were generated by homologous recombination. In brains of homozygous mutant mice, no specific binding of [3H]pyrilamine was seen. [3H]Doxepin has two saturable binding sites with higher and lower affinities in brains of wild-type mice, but H1R-deficient mice showed only the weak labeling of [3H]doxepin that corresponds to lower-affinity binding sites. Mutant mice develop normally, but absence of H1R significantly increased the ratio of ambulation during the light period to the total ambulation for 24 hr in an accustomed environment. In addition, mutant mice significantly reduced exploratory behavior of ambulation and rearings in a new environment. These results indicate that through H1R, histamine is involved in circadian rhythm of locomotor activity and exploratory behavior as a neurotransmitter. PMID:8917588

  16. Behavioral changes and dopaminergic dysregulation in mice lacking the nuclear receptor Rev-erbα.

    PubMed

    Jager, Jennifer; O'Brien, W Timothy; Manlove, Jessica; Krizman, Elizabeth N; Fang, Bin; Gerhart-Hines, Zachary; Robinson, Michael B; Klein, Peter S; Lazar, Mitchell A

    2014-04-01

    The regulation of behavior by the molecular components of the circadian clock is not well understood. Here we report that mice lacking the nuclear receptor Rev-erbα, a potent transcriptional repressor and core clock component, displayed marked hyperactivity and impaired response habituation in novel environments. In addition, Rev-erbα knockout (KO) mice were deficient in short-term, long-term, and contextual memories and also showed impairment in nest-building ability. Together, these results suggest that Rev-erbα KO mice manifest defective hippocampal function. Interestingly, the changes in novelty-induced locomotor activity of Rev-erbα KO mice were comparable at multiple times of day, potentially due to the muted amplitude of Rev-erbα oscillation in the hippocampus of wild-type mice. Hippocampal dopamine turnover was increased in Rev-erbα KO mice, due to up-regulation of tyrosine hydroxylase, the rate-limiting enzyme in dopamine production, and pharmacologic inhibition of tyrosine hydroxylase activity partially rescued locomotor hyperactivity. These findings reveal a novel, nonredundant function for Rev-erbα that links a core component of the circadian gene-regulatory network to the control of dopaminergic and hippocampus-dependent behaviors.

  17. Behavioral Changes and Dopaminergic Dysregulation in Mice Lacking the Nuclear Receptor Rev-erbα

    PubMed Central

    Jager, Jennifer; O'Brien, W. Timothy; Manlove, Jessica; Krizman, Elizabeth N.; Fang, Bin; Gerhart-Hines, Zachary; Robinson, Michael B.; Klein, Peter S.

    2014-01-01

    The regulation of behavior by the molecular components of the circadian clock is not well understood. Here we report that mice lacking the nuclear receptor Rev-erbα, a potent transcriptional repressor and core clock component, displayed marked hyperactivity and impaired response habituation in novel environments. In addition, Rev-erbα knockout (KO) mice were deficient in short-term, long-term, and contextual memories and also showed impairment in nest-building ability. Together, these results suggest that Rev-erbα KO mice manifest defective hippocampal function. Interestingly, the changes in novelty-induced locomotor activity of Rev-erbα KO mice were comparable at multiple times of day, potentially due to the muted amplitude of Rev-erbα oscillation in the hippocampus of wild-type mice. Hippocampal dopamine turnover was increased in Rev-erbα KO mice, due to up-regulation of tyrosine hydroxylase, the rate-limiting enzyme in dopamine production, and pharmacologic inhibition of tyrosine hydroxylase activity partially rescued locomotor hyperactivity. These findings reveal a novel, nonredundant function for Rev-erbα that links a core component of the circadian gene-regulatory network to the control of dopaminergic and hippocampus-dependent behaviors. PMID:24552589

  18. Mice Lacking Serotonin 2C Receptors Have increased Affective Responses to Aversive Stimuli

    PubMed Central

    Bonasera, Stephen J.; Schenk, A. Katrin; Luxenberg, Evan J.; Wang, Xidao; Basbaum, Allan; Tecott, Laurence H.

    2015-01-01

    Although central serotonergic systems are known to influence responses to noxious stimuli, mechanisms underlying serotonergic modulation of pain responses are unclear. We proposed that serotonin 2C receptors (5-HT2CRs), which are expressed within brain regions implicated in sensory and affective responses to pain, contribute to the serotonergic modulation of pain responses. In mice constitutively lacking 5-HT2CRs (2CKO mice) we found normal baseline sensory responses to noxious thermal, mechanical and chemical stimuli. In contrast, 2CKO mice exhibited a selective enhancement of affect-related ultrasonic afterdischarge vocalizations in response to footshock. Enhanced affect-related responses to noxious stimuli were also exhibited by 2CKO mice in a fear-sensitized startle assay. The extent to which a brief series of unconditioned footshocks produced enhancement of acoustic startle responses was markedly increased in 2CKO mice. As mesolimbic dopamine pathways influence affective responses to noxious stimuli, and these pathways are disinhibited in 2CKO mice, we examined the sensitivity of footshock-induced enhancement of startle to dopamine receptor blockade. Systemic administration of the dopamine D2/D3 receptor antagonist raclopride selectively reduced footshock-induced enhancement of startle without influencing baseline acoustic startle responses. We propose that 5-HT2CRs regulate affective behavioral responses to unconditioned aversive stimuli through mechanisms involving the disinhibition of ascending dopaminergic pathways. PMID:26630489

  19. Lack of Neuropathy-Related Phenotypes in Hint1 Knockout Mice

    PubMed Central

    Seburn, Kevin L.; Morelli, Kathryn H.; Jordanova, Albena; Burgess, Robert W.

    2014-01-01

    Mutations in HINT1, the gene encoding histidine triad nucleotide-binding protein 1 (HINT1), cause a recessively inherited peripheral neuropathy that involves primarily motor dysfunction and is usually associated with neuromyotonia, i.e. prolonged muscle contraction resulting from hyperexcitability of the peripheral nerve. Because these mutations are hypothesized to cause loss of function, we analyzed Hint1 knockout mice for their relevance as a disease model. Mice lacking Hint1 were normal in appearance and in behavioral tests or motor performance, although they moved slower and for a smaller fraction of time than wild-type (WT) mice in an open field arena. Muscles, neuromuscular junctions, and nodes of Ranvier are anatomically normal and did not show evidence of degeneration or regeneration. Axon numbers and myelination in peripheral nerves were normal at 4 and 13 months of age. Axons were slightly smaller than those in WT mice at 4 months of age, but this did not cause a decrease in conduction velocity, and no differences in axon diameters were detected at 13 months. Using electromyography, we were unable to detect neuromyotonia, even using supra-physiological stimuli and stressors such as reduced temperature or 3,4 diaminopyridine to block potassium channels. Therefore, we conclude that Hint1 knockout mice may be useful for studying the biochemical activities of HINT1, but these mice do not provide a disease model or a means for investigating the basis of HINT1-associated neuropathy and neuromyotonia. PMID:24918641

  20. Progressive impairment of kidneys and reproductive organs in mice lacking Rho GDIalpha.

    PubMed

    Togawa, A; Miyoshi, J; Ishizaki, H; Tanaka, M; Takakura, A; Nishioka, H; Yoshida, H; Doi, T; Mizoguchi, A; Matsuura, N; Niho, Y; Nishimune, Y; Nishikawa, S i; Takai, Y

    1999-09-23

    The Rho small G protein family members regulate various actin cytoskeleton-dependent cell functions. The Rho GDI (GDP dissociation inhibitor) family, consisting of Rho GDIalpha, -beta, and -gamma, is a regulator that keeps the Rho family members in the cytosol as the GDP-bound inactive form and translocates the GDP-bound form from the membranes to the cytosol after the GTP-bound form accomplishes their functions. Rho GDIalpha is ubiquitously expressed in mouse tissues and shows GDI activity on all the Rho family members in vitro. We have generated mice lacking Rho GDIalpha by homologous recombination to clarify its in vivo function. Rho GDIalpha -/- mice showed several abnormal phenotypes. Firstly, Rho GDIalpha -/- mice were initially viable but developed massive proteinuria mimicking nephrotic syndrome, leading to death due to renal failure within a year. Histologically, degeneration of tubular epithelial cells and dilatation of distal and collecting tubules were readily detected in the kidneys. Secondly, Rho GDIalpha -/- male mice were infertile and showed impaired spermatogenesis with vacuolar degeneration of seminiferous tubules in their testes. Thirdly, Rho GDIalpha -/- embryos derived from Rho GDIalpha -/- female mice were defective in the postimplantation development. In addition, these morphological and functional abnormalities showed age-dependent progression. These results suggest that the signaling pathways of the Rho family members regulated by Rho GDIalpha play important roles in maintaining the structure and physiological function of at least kidneys and reproductive systems in adult mice.

  1. Postreceptoral contributions to the light-adapted ERG of mice lacking b-waves.

    PubMed

    Shirato, Suguru; Maeda, Hidetaka; Miura, Gen; Frishman, Laura J

    2008-06-01

    The purpose of this study was to determine the contributions of postreceptoral neurons to the light-adapted ERG of the Nob mouse, a model for complete-type congenital stationary night blindness (CSNB1) that lacks a b-wave from depolarizing bipolar cells. Ganzfeld ERGs were recorded from anesthetized adult control mice, control mice injected intravitreally with L-2-amino-4-phosphonobutyric acid (Control APB mice) to remove On pathway activity, and Nob mice. ERGs also were recorded after PDA (cis-2,3-piperidine-dicarboxylic acid, 3-5mM) was injected to block transmission to hyperpolarizing (Off) bipolar and horizontal cells, and all third-order neurons. Stimuli were brief (<4ms, 0.4-2.5log sc td s) and long (200ms, 2.5-4.6log sc td) LED flashes (lambda(max)=513nm, on a rod suppressing background (2.6log sc td). Sinusoidal modulation of the LEDs (mean, 2.6log sc td; contrast, 100%; 3-36Hz) was used to study flicker ERGs. Brief-flash ERGs of Nob mice presented as long-lasting negative waves with a positive-going intrusion that started about 50ms after the flash and peaked around 120ms. Control APB mice had similar responses, and in both cases, PDA removed the positive-going intrusion. For long flashes, PDA removed a small, slow "d-wave" after light offset. With sinusoidal stimulation, the fundamental (F1) amplitude of control mice ERG peaked at 8Hz ( approximately 70microV). For Nob mice the peak was approximately 20microV at 6Hz before PDA and approximately 10muV at 3Hz or lower after PDA. F1 responses were present up to 21Hz in control and Nob eyes and 15Hz in Nob eyes after PDA. Between 3 and 6Hz, F1 phase was 170-210 degrees more delayed in Nob than control mice; phase was hardly altered by PDA. With vector analysis, a substantial postreceptoral input to the Nob flicker ERG was revealed. In control mice, the second harmonic (F2) response showed peaks of approximately 10mocrpV at 3Hz and 13Hz. Nob mice showed almost no F2. In summary, in this study it was found that

  2. Mice carrying a CAR-2 null allele lack carbonic anhydrase II immunohistochemically and show vascular calcification.

    PubMed Central

    Spicer, S. S.; Lewis, S. E.; Tashian, R. E.; Schulte, B. A.

    1989-01-01

    Mutant mice reported to lack carbonic anhydrase isoenzyme II (CA II) have been examined here for immunocytochemical evidence of CA II and for histopathologic change. All histologic sites that immunostain for CA II in a wide range of organs in normal mice failed to show such immunoreactivity in the homozygous mutants. The CA II-deficient mice differed from controls in evidencing an age dependent medial calcification of small arteries in a number of organs. The male genital tract revealed the most extensive arterial calcinosis and males were possibly more affected in general than females. One or another Car-2n/Car-2n mouse showed changes additionally in uterus, small bowel, lymph nodes, or renal pelvis. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 PMID:2495727

  3. Sensorineural deafness and seizures in mice lacking vesicular glutamate transporter 3.

    PubMed

    Seal, Rebecca P; Akil, Omar; Yi, Eunyoung; Weber, Christopher M; Grant, Lisa; Yoo, Jong; Clause, Amanda; Kandler, Karl; Noebels, Jeffrey L; Glowatzki, Elisabeth; Lustig, Lawrence R; Edwards, Robert H

    2008-01-24

    The expression of unconventional vesicular glutamate transporter VGLUT3 by neurons known to release a different classical transmitter has suggested novel roles for signaling by glutamate, but this distribution has raised questions about whether the protein actually contributes to glutamate release. We now report that mice lacking VGLUT3 are profoundly deaf due to the absence of glutamate release from hair cells at the first synapse in the auditory pathway. The early degeneration of some cochlear ganglion neurons in knockout mice also indicates an important developmental role for the glutamate released by hair cells before the onset of hearing. In addition, the mice exhibit primary, generalized epilepsy that is accompanied by remarkably little change in ongoing motor behavior. The glutamate release conferred by expression of VGLUT3 thus has an essential role in both function and development of the auditory pathway, as well as in the control of cortical excitability.

  4. Mice lacking functional STAT1 are highly susceptible to lethal infection with Lassa virus.

    PubMed

    Yun, Nadezhda E; Seregin, Alexey V; Walker, David H; Popov, Vsevolod L; Walker, Aida G; Smith, Jeanon N; Miller, Milagros; de la Torre, Juan C; Smith, Jennifer K; Borisevich, Viktoriya; Fair, Joseph N; Wauquier, Nadia; Grant, Donald S; Bockarie, Bayon; Bente, Dennis; Paessler, Slobodan

    2013-10-01

    Lassa fever (LF) is a potentially lethal human disease that is caused by the arenavirus Lassa virus (LASV). Annually, around 300,000 infections with up to 10,000 deaths occur in regions of Lassa fever endemicity in West Africa. Here we demonstrate that mice lacking a functional STAT1 pathway are highly susceptible to infection with LASV and develop lethal disease with pathology similar to that reported in humans.

  5. Slight alteration of the electroretinogram in mice lacking dystrophin dp71.

    PubMed

    Cia, David; Simonutti, Manuel; Fort, Patrice E; Doly, Michel; Rendon, Alvaro

    2014-01-01

    Most Duchenne muscular dystrophy patients and the mdx(Cv3) mouse strain, lacking expression of both dystrophins Dp260 and Dp71, show a high attenuation of the dark-adapted electroretinogram (ERG) b-wave amplitude, whereas mice lacking the expression of Dp260 show normal b-wave amplitude. Here, we completed our assessment of whether the sole absence of Dp71 affects the ERG. Ganzfeld ERGs were performed on dark-adapted Dp71-null mice and littermates. Scotopic flash ERGs were recorded at light intensities from 3.10-(5) to 1 cd.s/m(2). Oscillatory potentials (OPs) were extracted at 1 cd.s/m(2). Photopic flash ERGs were recorded at 10 cd.s/m(2) after light adaptation. Dp71-null mice showed a slight but significant reduction in b-wave amplitudes, normal a-wave amplitudes and nonaffected implicit times of the scotopic ERGs. No changes were observed in the amplitudes and implicit times of the OPs and the photopic ERGs. Our results demonstrate that together both Dp71 and Dp260 are required for the generation of the ERG b-wave in mice. © 2014 S. Karger AG, Basel.

  6. Mice lacking selenoprotein P and selenocysteine lyase exhibit severe neurological dysfunction, neurodegeneration, and audiogenic seizures.

    PubMed

    Byrns, China N; Pitts, Matthew W; Gilman, Christy A; Hashimoto, Ann C; Berry, Marla J

    2014-04-04

    Selenoproteins are a unique family of proteins, characterized by the co-translational incorporation of selenium as selenocysteine, which play key roles in antioxidant defense. Among selenoproteins, selenoprotein P (Sepp1) is particularly distinctive due to the fact that it contains multiple selenocysteine residues and has been postulated to act in selenium transport. Within the brain, Sepp1 delivers selenium to neurons by binding to the ApoER2 receptor. Upon feeding a selenium-deficient diet, mice lacking ApoER2 or Sepp1 develop severe neurological dysfunction and exhibit widespread brainstem neurodegeneration, indicating an important role for ApoER2-mediated Sepp1 uptake in normal brain function. Selenocysteine lyase (Scly) is an enzyme that plays an important role in selenium homeostasis, in that it catalyzes the decomposition of selenocysteine and allows selenium to be recycled for additional selenoprotein synthesis. We previously reported that constitutive deletion of Scly results in neurological deficits only when mice are challenged with a low selenium diet. To gain insight into the relationship between Sepp1 and Scly in selenium metabolism, we created novel transgenic mice constitutively lacking both genes (Scly(-/-)Sepp1(-/-)) and characterized the neurobehavioral phenotype. We report that deletion of Scly in conjunction with Sepp1 further aggravates the phenotype of Sepp1(-/-) mice, as these mice needed supraphysiological selenium supplementation to survive, and surviving mice exhibited impaired motor coordination, audiogenic seizures, and brainstem neurodegeneration. These findings provide the first in vivo evidence that Scly and Sepp1 work cooperatively to maintain selenoprotein function in the mammalian brain.

  7. Improved glycemic control in mice lacking Sglt1 and Sglt2.

    PubMed

    Powell, David R; DaCosta, Christopher M; Gay, Jason; Ding, Zhi-Ming; Smith, Melinda; Greer, Jennifer; Doree, Deon; Jeter-Jones, Sabrina; Mseeh, Faika; Rodriguez, Lawrence A; Harris, Angela; Buhring, Lindsey; Platt, Kenneth A; Vogel, Peter; Brommage, Robert; Shadoan, Melanie K; Sands, Arthur T; Zambrowicz, Brian

    2013-01-15

    Sodium-glucose cotransporter 2 (SGLT2) is the major, and SGLT1 the minor, transporter responsible for renal glucose reabsorption. Increasing urinary glucose excretion (UGE) by selectively inhibiting SGLT2 improves glycemic control in diabetic patients. We generated Sglt1 and Sglt2 knockout (KO) mice, Sglt1/Sglt2 double-KO (DKO) mice, and wild-type (WT) littermates to study their relative glycemic control and to determine contributions of SGLT1 and SGLT2 to UGE. Relative to WTs, Sglt2 KOs had improved oral glucose tolerance and were resistant to streptozotocin-induced diabetes. Sglt1 KOs fed glucose-free high-fat diet (G-free HFD) had improved oral glucose tolerance accompanied by delayed intestinal glucose absorption and increased circulating glucagon-like peptide-1 (GLP-1), but had normal intraperitoneal glucose tolerance. On G-free HFD, Sglt2 KOs had 30%, Sglt1 KOs 2%, and WTs <1% of the UGE of DKOs. Consistent with their increased UGE, DKOs had lower fasting blood glucose and improved intraperitoneal glucose tolerance than Sglt2 KOs. In conclusion, 1) Sglt2 is the major renal glucose transporter, but Sglt1 reabsorbs 70% of filtered glucose if Sglt2 is absent; 2) mice lacking Sglt2 display improved glucose tolerance despite UGE that is 30% of maximum; 3) Sglt1 KO mice respond to oral glucose with increased circulating GLP-1; and 4) DKO mice have improved glycemic control over mice lacking Sglt2 alone. These data suggest that, in patients with type 2 diabetes, combining pharmacological SGLT2 inhibition with complete renal and/or partial intestinal SGLT1 inhibition may improve glycemic control over that achieved by SGLT2 inhibition alone.

  8. Regulation of ENaC in mice lacking renal insulin receptors in the collecting duct

    PubMed Central

    Pavlov, Tengis S.; Ilatovskaya, Daria V.; Levchenko, Vladislav; Li, Lijun; Ecelbarger, Carolyn M.; Staruschenko, Alexander

    2013-01-01

    The epithelial sodium channel (ENaC) is one of the central effectors involved in regulation of salt and water homeostasis in the kidney. To study mechanisms of ENaC regulation, we generated knockout mice lacking the insulin receptor (InsR KO) specifically in the collecting duct principal cells. Single-channel analysis in freshly isolated split-open tubules demonstrated that the InsR-KO mice have significantly lower ENaC activity compared to their wild-type (C57BL/6J) littermates when animals were fed either normal or sodium-deficient diets. Immunohistochemical and Western blot assays demonstrated no significant changes in expression of ENaC subunits in InsR-KO mice compared to wild-type littermates. Insulin treatment caused greater ENaC activity in split-open tubules isolated from wild-type mice but did not have this effect in the InsR-KO mice. Thus, these results suggest that insulin increases ENaC activity via its own receptor affecting the channel open probability. To further determine the mechanism of the action of insulin on ENaC, we used mouse mpkCCDc14 principal cells. Insulin significantly augmented amiloride-sensitive transepithelial flux in these cells. Pretreatment of the mpkCCDc14 cells with phosphatidylinositol 3-kinase (LY294002; 10 μM) or mTOR (PP242; 100 nM) inhibitors precluded this effect. This study provides new information about the importance of insulin receptors expressed in collecting duct principal cells for ENaC activity.—Pavlov, T. S., Ilatovskaya, D. V., Levchenko, V., Li, L., Ecelbarger, C. M., Staruschenko, A. Regulation of ENaC in mice lacking renal insulin receptors in the collecting duct. PMID:23558339

  9. Absence epilepsy and sinus dysrhythmia in mice lacking the pacemaker channel HCN2

    PubMed Central

    Ludwig, Andreas; Budde, Thomas; Stieber, Juliane; Moosmang, Sven; Wahl, Christian; Holthoff, Knut; Langebartels, Anke; Wotjak, Carsten; Munsch, Thomas; Zong, Xiangang; Feil, Susanne; Feil, Robert; Lancel, Marike; Chien, Kenneth R.; Konnerth, Arthur; Pape, Hans-Christian; Biel, Martin; Hofmann, Franz

    2003-01-01

    Hyperpolarization-activated cation (HCN) channels are believed to be involved in the generation of cardiac pacemaker depolarizations as well as in the control of neuronal excitability and plasticity. The contributions of the four individual HCN channel isoforms (HCN1–4) to these diverse functions are not known. Here we show that HCN2-deficient mice exhibit spontaneous absence seizures. The thalamocortical relay neurons of these mice displayed a near complete loss of the HCN current, resulting in a pronounced hyperpolarizing shift of the resting membrane potential, an altered response to depolarizing inputs and an increased susceptibility for oscillations. HCN2-null mice also displayed cardiac sinus dysrhythmia, a reduction of the sinoatrial HCN current and a shift of the maximum diastolic potential to hyperpolarized values. Mice with cardiomyocyte- specific deletion of HCN2 displayed the same dysrhythmia as mice lacking HCN2 globally, indicating that the dysrhythmia is indeed caused by sinoatrial dysfunction. Our results define the physiological role of the HCN2 subunit as a major determinant of membrane resting potential that is required for regular cardiac and neuronal rhythmicity. PMID:12514127

  10. Increased context-dependent conditioning to amphetamine in mice lacking TAAR1.

    PubMed

    Sukhanov, Ilya; Caffino, Lucia; Efimova, Evgeniya V; Espinoza, Stefano; Sotnikova, Tatiana D; Cervo, Luigi; Fumagalli, Fabio; Gainetdinov, Raul R

    2016-01-01

    Given the recent evidence indicating that amphetamine derivatives may also act as direct agonists of the G protein-coupled trace amine-associated receptor 1 (TAAR1), we hypothesized that TAAR1 could contribute to the reinforcing and addictive properties of amphetamines. Accordingly, the present study aimed to investigate the role of TAAR1 in the effects of psychostimulants by analyzing context-dependent sensitization and conditioned place preference (CPP) to d-amphetamine (AMPH) in TAAR1-KO mice. In context-dependent sensitization experiment, TAAR1-KO mice showed higher conditioned locomotor responses compared to wild-type mice. In the CPP test, TAAR1-KO animals were also more sensitive to priming-induced reinstatement of AMPH-induced conditioned place preference (CPP) than wild type mice. Importantly, saline-treated and AMPH-treated mice lacking TAAR1 demonstrated significant alterations in the total levels and phosphorylation of the critical subunit of NMDA glutamate receptors, GluN1, in the striatum, suggesting a role of TAAR1 in the modulation of frontostriatal glutamate transmission; this effect could underlie the observed alterations in conditioning processes. In conclusion, our data suggest that TAAR1 receptors play an inhibitory role with respect to conditioned responses to AMPH by modulating, at least in part, corticostriatal glutamate transmission. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Lack of Melanopsin Is Associated with Extreme Weight Loss in Mice upon Dietary Challenge.

    PubMed

    Aytürk, Didem Göz; Castrucci, Ana Maria; Carr, David E; Keller, Susanna R; Provencio, Ignacio

    2015-01-01

    Metabolic disorders have been established as major risk factors for ocular complications and poor vision. However, little is known about the inverse possibility that ocular disease may cause metabolic dysfunction. To test this hypothesis, we assessed the metabolic consequences of a robust dietary challenge in several mouse models suffering from retinal mutations. To this end, mice null for melanopsin (Opn4-/-), the photopigment of intrinsically photosensitive retinal ganglion cells (ipRGCs), were subjected to five weeks of a ketogenic diet. These mice lost significantly more weight than wild-type controls or mice lacking rod and cone photoreceptors (Pde6brd1/rd1). Although ipRGCs are critical for proper circadian entrainment, and circadian misalignment has been implicated in metabolic pathology, we observed no differences in entrainment between Opn4-/- and control mice. Additionally, we observed no differences in any tested metabolic parameter between these mouse strains. Further studies are required to establish the mechanism giving rise to this dramatic phenotype observed in melanopsin-null mice. We conclude that the causality between ocular disease and metabolic disorders merits further investigation due to the popularity of diets that rely on the induction of a ketogenic state. Our study is a first step toward understanding retinal pathology as a potential cause of metabolic dysfunction.

  12. Hypoglycemic effect of insulin-like growth factor-1 in mice lacking insulin receptors.

    PubMed Central

    Di Cola, G; Cool, M H; Accili, D

    1997-01-01

    We have investigated the metabolic actions of recombinant human IGF-1 in mice genetically deficient of insulin receptors (IR-/-). After intraperitoneal administration, IGF-1 caused a prompt and sustained decrease of plasma glucose levels in IR-/- mice. Plasma free fatty acid concentrations were unaffected. Interestingly, the effects of IGF-1 were identical in normal mice (IR+/+) and in IR-/- mice. Despite decreased glucose levels, IR-/- mice treated with IGF-1 died within 2-3 d of birth, like sham-treated IR-/- controls. In skeletal muscle, IGF-1 treatment caused phosphorylation of IGF-1 receptors and increased the levels of the phosphatidylinositol-3-kinase p85 subunit detected in antiphosphotyrosine immunoprecipitates, consistent with the possibility that IGF-1 stimulates glucose uptake in a phosphatidylinositol-3-kinase-dependent manner. IGF-1 receptor phosphorylation and coimmunoprecipitation of phosphatidylinositol3-kinase by antiphosphotyrosine antibodies was also observed in liver, and was associated with a decrease in mRNA levels of the key gluconeogenetic enzyme phosphoenolpyruvate carboxykinase. Thus, the effect of IGF-1 on plasma glucose levels may be accounted for by increased peripheral glucose use and by inhibition of hepatic gluconeogenesis. These data indicate that IGF-1 can mimic insulin's effects on glucose metabolism by acting through its own receptor. The failure of IGF-1 to rescue the lethal phenotype due to lack of insulin receptors suggests that IGF-1 receptors cannot effectively mediate all the metabolic actions of insulin receptors. PMID:9153298

  13. Mice lacking angiotensin-converting enzyme have low blood pressure, renal pathology, and reduced male fertility.

    PubMed

    Esther, C R; Howard, T E; Marino, E M; Goddard, J M; Capecchi, M R; Bernstein, K E

    1996-05-01

    Mammals produce two isozymes of angiotensin-converting enzyme (ACE). Somatic ACE plays an important role in the control of blood pressure. The function of testis ACE, produced by male and germ cells, is not known. To examine the roles of these isozymes, we used targeted homologous recombination to introduce a modified ACE allele into a mouse line. Mice homozygous for this mutant allele lack both ACE isozymes and have markedly reduced blood pressures. Contrary to a previous report, we found heterozygous male mice to have normal blood pressures. Homozygous mutant mice also have severe renal disease. The renal papilla is markedly reduced, and the intrarenal arteries exhibit vascular hyperplasia associated with a perivascular inflammatory infiltrate. These animals cannot effectively concentrate urine. They also have an abnormally low urinary sodium to potassium ratio despite reduced levels of aldosterone. Homozygous mutant male mice sire significantly smaller litters than wild-type male mice; however, no defect in sperm number, morphology, or motility was detected. ACE-deficient animals demonstrate the role of this enzyme in systemic blood pressure, renal development and function, and male fertility.

  14. Preserved recovery of cardiac function following ischemia-reperfusion in mice lacking SIRT3.

    PubMed

    Koentges, Christoph; Pfeil, Katharina; Meyer-Steenbuck, Maximilian; Lother, Achim; Hoffmann, Michael M; Odening, Katja E; Hein, Lutz; Bode, Christoph; Bugger, Heiko

    2016-01-01

    Lack of the mitochondrial deacetylase sirtuin 3 (SIRT3) impairs mitochondrial function and increases the susceptibility to induction of the mitochondrial permeability transition pore. Because these alterations contribute to myocardial ischemia-reperfusion (IR) injury, we hypothesized that SIRT3 deficiency may increase cardiac injury following myocardial IR. Hearts of 10-week-old mice were perfused in the isolated working mode and subjected to 17.5 min of global no-flow ischemia, followed by 30 min of reperfusion. Measurements before ischemia revealed a decrease in cardiac power (-20%) and rate pressure product (-15%) in SIRT3(-/-) mice. Mitochondrial state 3 respiration (-15%), ATP synthesis (-39%), and ATP/O ratios (-29%) were decreased in hearts of SIRT3(-/-) mice. However, percent recovery of cardiac power (WT 94% ± 9%; SIRT3(-/-) 89% ± 9%) and rate pressure product (WT 89% ± 16%; SIRT3(-/-) 96% ± 3%) following IR was similar in both groups. Myocardial infarct size was not increased in SIRT3(-/-) mice following permanent ligation of the left anterior descending coronary artery (LAD). Left ventricular pressure and dP/dtmax, and mitochondrial respiration and ATP synthesis were not different between groups following LAD ligation. Thus, despite pre-existing defects in cardiac function and mitochondrial respiratory capacity in SIRT3(-/-) mice, SIRT3 deficiency does not additionally impair cardiac function following IR or following myocardial infarction.

  15. Behavioural phenotypic characterization of CD-1 mice lacking the neuropeptide S receptor.

    PubMed

    Ruzza, C; Pulga, A; Rizzi, A; Marzola, G; Guerrini, R; Calo', G

    2012-04-01

    Neuropeptide S (NPS) is the endogenous ligand of a previously orphan receptor now named NPSR. In the brain NPS regulates several biological functions including anxiety, arousal, locomotion, food intake, learning and memory, pain and drug abuse. Mice lacking the NPSR gene (NPSR(-/-)) represent an useful tool to investigate the neurobiology of the NPS/NPSR system. NPSR(-/-) mice have been generated in a 129S6/SvEv genetic background. In the present study we generated CD-1 congenic NPSR(+/+) and NPSR(-/-) mice and investigated their phenotype and sensitivity to NPS in various behavioural assays. The phenotype analysis revealed no locomotor differences between NPSR(+/+) and NPSR(-/-) mice. The behaviour of NPSR(+/+) and NPSR(-/-) mice in the righting reflex test was superimposable. No differences were recorded between the two genotypes in the elevated plus maze, open field and stress-induced hyperthermia tests, with the exception of rearing behaviour that was reduced in knockout animals. Moreover the behaviour of NPSR(+/+) and NPSR(-/-) mice in the forced swimming, novel object recognition and formalin assays was similar. The stimulatory effects of NPS in the locomotor activity test and its anxiolytic-like actions in the elevated plus maze and open field assays were evident in NPSR(+/+) but not NPSR(-/-) animals. In conclusion, the present study indicates that the NPS/NPSR system does not tonically control locomotion, sensitivity to diazepam, anxiety, depressive-like behaviours, memory and pain transmission in mice. Furthermore our results clearly show that the product of the NPSR gene represents the mandatory protein for all the NPS biological effects so far described.

  16. Ethanol-related behaviors in mice lacking the sigma-1 receptor.

    PubMed

    Valenza, Marta; DiLeo, Alyssa; Steardo, Luca; Cottone, Pietro; Sabino, Valentina

    2016-01-15

    The Sigma-1 receptor (Sig-1R) is a chaperone protein that has been implicated in drug abuse and addiction. Multiple studies have characterized the role the Sig-1R plays in psychostimulant addiction; however, fewer studies have specifically investigated its role in alcohol addiction. We have previously shown that antagonism of the Sig-1R reduces excessive drinking and motivation to drink, whereas agonism induces binge-like drinking in rodents. The objectives of these studies were to investigate the impact of Sig-1R gene deletion in C57Bl/6J mice on ethanol drinking and other ethanol-related behaviors. We used an extensive panel of behavioral tests to examine ethanol actions in male, adult mice lacking Oprs1, the gene encoding the Sig-1R. To compare ethanol drinking behavior, Sig-1 knockout (KO) and wild type (WT) mice were subject to a two-bottle choice, continuous access paradigm with different concentrations of ethanol (3-20% v/v) vs. water. Consumption of sweet and bitter solutions was also assessed in Sig-1R KO and WT mice. Finally, motor stimulant sensitivity, taste aversion and ataxic effects of ethanol were assessed. Sig-1R KO mice displayed higher ethanol intake compared to WT mice; the two genotypes did not differ in their sweet or bitter taste perception. Sig-1R KO mice showed lower sensitivity to ethanol stimulant effects, but greater sensitivity to its taste aversive effects. Ethanol-induced sedation was instead unaltered in the mutants. Our results prove that the deletion of the Sig-1R increases ethanol consumption, likely by decreasing its rewarding effects, and therefore indicating that the Sig-1R is involved in modulation of the reinforcing effects of alcohol. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Ethanol-related behaviors in mice lacking the sigma-1 receptor

    PubMed Central

    Valenza, Marta; DiLeo, Alyssa; Steardo, Luca; Cottone, Pietro; Sabino, Valentina

    2015-01-01

    Rationale The Sigma-1 receptor (Sig-1R) is a chaperone protein that has been implicated in drug abuse and addiction. Multiple studies have characterized the role the Sig-1R plays in psychostimulants addiction, but fewer studies have specifically investigated its role in alcohol addiction. We have previously shown that antagonism of the Sig-1R reduces excessive drinking and motivation to drink, whereas agonism induces binge-like drinking in rodents. Objectives The objectives of these studies were to investigate the impact of Sig-1R gene deletion in C57Bl/6J mice on ethanol drinking and other ethanol-related behaviors. Methods We used an extensive panel of behavioral tests to examine ethanol actions in male, adult mice lacking Oprs1, the gene encoding the Sig-1R. To compare ethanol drinking behavior, Sig-1 knockout (KO) and wild type (WT) mice were subject to a two-bottle choice, continuous access paradigm with different concentrations of ethanol (3%–20% v/v) vs. water. Consumption of sweet and bitter solutions was also assessed in Sig-1R KO and WT mice. Finally, motor stimulant sensitivity, taste aversion and ataxic effects of ethanol were assessed. Results Sig-1R KO mice displayed higher ethanol intake compared to WT mice; the two genotypes did not differ in their sweet or bitter taste perception. Sig-1R KO mice showed lower sensitivity to ethanol stimulant effects, but greater sensitivity to its taste aversive effects. Ethanol-induced sedation was unaltered in the mutants. Conclusions Our results suggest that the deletion of the Sig-1R increases ethanol consumption, likely by decreasing its rewarding effects, and therefore indicating that the Sig-1R is involved in modulation of the reinforcing effects of alcohol. PMID:26462569

  18. Alteration in plasma testosterone levels in male mice lacking soluble epoxide hydrolase.

    PubMed

    Luria, Ayala; Morisseau, Christophe; Tsai, Hsing-Ju; Yang, Jun; Inceoglu, Bora; De Taeye, Bart; Watkins, Steven M; Wiest, Michelle M; German, J Bruce; Hammock, Bruce D

    2009-08-01

    Soluble epoxide hydrolase (Ephx2, sEH) is a bifunctional enzyme with COOH-terminal hydrolase and NH(2)-terminal phosphatase activities. sEH converts epoxyeicosatrienoic acids (EETs) to dihydroxyeicosatrienoic acids (DHETs), and the phosphatase activity is suggested to be involved in cholesterol metabolism. EETs participate in a wide range of biological functions, including regulation of vascular tone, renal tubular transport, cardiac contractility, and inflammation. Inhibition of sEH is a potential approach for enhancing the biological activity of EETs. Therefore, disruption of sEH activity is becoming an attractive therapeutic target for both cardiovascular and inflammatory diseases. To define the physiological role of sEH, we characterized a knockout mouse colony lacking expression of the Ephx2 gene. Lack of sEH enzyme is characterized by elevation of EET to DHET ratios in both the linoleate and arachidonate series in plasma and tissues of both female and male mice. In male mice, this lack of expression was also associated with decreased plasma testosterone levels, sperm count, and testicular size. However, this genotype was still able to sire litters. Plasma cholesterol levels also declined in this genotype. Behavior tests such as anxiety-like behavior and hedonic response were also examined in Ephx2-null and WT mice, as all can be related to hormonal changes. Null mice showed a level of anxiety with a decreased hedonic response. In conclusion, this study provides a broad biochemical, physiological, and behavioral characterization of the Ephx2-null mouse colony and suggests a mechanism by which sEH and its substrates may regulate circulating levels of testosterone through cholesterol biosynthesis and metabolism.

  19. Increased renal renin content in mice lacking the Na+/H+ exchanger NHE2.

    PubMed

    Hanner, Fiona; Chambrey, Régine; Bourgeois, Soline; Meer, Elliott; Mucsi, István; Rosivall, László; Shull, Gary E; Lorenz, John N; Eladari, Dominique; Peti-Peterdi, János

    2008-04-01

    Macula densa (MD) cells express the Na(+)/H(+) exchanger (NHE) isoform NHE2 at the apical membrane, which may play an important role in tubular salt sensing through the regulation of cell volume and intracellular pH. These studies aimed to determine whether NHE2 participates in the MD control of renin synthesis. Renal renin content and activity and elements of the MD signaling pathway were analyzed using wild-type (NHE2(+/+)) and NHE2 knockout (NHE2(-/-)) mice. Immunofluorescence studies indicated that NHE2(-/-) mice lack NHE3 at the MD apical membrane, so the other apical NHE isoform has not compensated for the lack of NHE2. Importantly, the number of renin-expressing cells in the afferent arteriole in NHE2(-/-) mice was increased approximately 2.5-fold using renin immunohistochemistry. Western blotting confirmed approximately 20% higher renal cortical renin content in NHE2(-/-) mice compared with wild type. No-salt diet for 1 wk significantly increased renin content and activity in NHE2(+/+) mice, but the response was blunted in NHE2(-/-) mice. Renal tissue renin activity and plasma renin concentration were elevated three- and twofold, respectively, in NHE2(-/-) mice compared with wild type. NHE2(-/-) mice also exhibited a significantly increased renal cortical cyclooxygenase-2 (COX-2) and microsomal prostaglandin E synthase (mPGES) expression, indicating MD-specific mechanisms responsible for the increased renin content. Significant and chronic activation of ERK1/2 was observed in MD cells of NHE2(-/-) kidneys. Removal of salt or addition of NHE inhibitors to cultured mouse MD-derived (MMDD1) cells caused a time-dependent activation of ERK1/2. In conclusion, the NHE2 isoform appears to be important in the MD feedback control of renin secretion, and the signaling pathway likely involves MD cell shrinkage and activation of ERK1/2, COX-2, and mPGES, all well-established elements of the MD-PGE(2)-renin release pathway.

  20. Nicotine anxiogenic and rewarding effects are decreased in mice lacking β-endorphin

    PubMed Central

    Trigo, José M.; Zimmer, Andreas; Maldonado, Rafael

    2009-01-01

    The endogenous opioid system plays an important role in the behavioral effects of nicotine. Thus, μ-opioid receptor and the endogenous opioids derived from proenkephalin are involved in the central effects of nicotine. However, the role played by the different endogenous opioid peptides in the acute and chronic effects of nicotine remains to be fully established. Mice lacking β-endorphin were acutely injected with nicotine at different doses to evaluate locomotor, anxiogenic and antinociceptive responses. The rewarding properties of nicotine were evaluated by using the conditioned place-preference paradigm. Mice chronically treated with nicotine were acutely injected with mecamylamine to study the behavioral expression of nicotine withdrawal. Mice lacking β-endorphin exhibited a spontaneous hypoalgesia and hyperlocomotion and a reduction on the anxiogenic and rewarding effects induced by nicotine. Nicotine induced similar antinociception and hypolocomotion in both genotypes and no differences were found in the development of physical dependence. The dissociation between nicotine rewarding properties and physical dependence suggests a differential implication of β-endorphin in these addictive related responses. PMID:19376143

  1. Nicotine anxiogenic and rewarding effects are decreased in mice lacking beta-endorphin.

    PubMed

    Trigo, José M; Zimmer, Andreas; Maldonado, Rafael

    2009-06-01

    The endogenous opioid system plays an important role in the behavioral effects of nicotine. Thus, micro-opioid receptor and the endogenous opioids derived from proenkephalin are involved in the central effects of nicotine. However, the role played by the different endogenous opioid peptides in the acute and chronic effects of nicotine remains to be fully established. Mice lacking beta-endorphin were acutely injected with nicotine at different doses to evaluate locomotor, anxiogenic and antinociceptive responses. The rewarding properties of nicotine were evaluated by using the conditioned place-preference paradigm. Mice chronically treated with nicotine were acutely injected with mecamylamine to study the behavioral expression of nicotine withdrawal. Mice lacking beta-endorphin exhibited a spontaneous hypoalgesia and hyperlocomotion and a reduction on the anxiogenic and rewarding effects induced by nicotine. Nicotine induced similar antinociception and hypolocomotion in both genotypes and no differences were found in the development of physical dependence. The dissociation between nicotine rewarding properties and physical dependence suggests a differential implication of beta-endorphin in these addictive related responses.

  2. Entrainment and phase-shifting by centrifugation abolished in mice lacking functional vestibular input

    NASA Astrophysics Data System (ADS)

    Fuller, Charles; Ringgold, Kristyn

    The circadian pacemaker can be phase shifted and entrained by appropriately timed locomotor activity, however the mechanism(s) involved remain poorly understood. Recent work in our lab has suggested the involvement of the vestibular otolith organs in activity-induced changes within the circadian timing system (CTS). For example, we have shown that changes in circa-dian period and phase in response to locomotion (wheel running) require functional macular gravity receptors. We believe the neurovestibular system is responsible for the transduction of gravitoinertial input associated with the types of locomotor activity that are known to af-fect the pacemaker. This study investigated the hypothesis that daily, timed gravitoinertial stimuli, as applied by centrifugation. would induce entrainment of circadian rhythms in only those animals with functional afferent vestibular input. To test this hypothesis, , chemically labyrinthectomized (Labx) mice, mice lacking macular vestibular input (head tilt or hets) and wildtype (WT) littermates were implanted i.p. with biotelemetry and individually housed in a 4-meter diameter centrifuge in constant darkness (DD). After 2 weeks in DD, the mice were exposed daily to 2G via centrifugation from 1000-1200 for 9 weeks. Only WT mice showed entrainment to the daily 2G pulse. The 2G pulse was then re-set to occur at 1200-1400 for 4 weeks. Only WT mice demonstrated a phase shift in response to the re-setting of the 2G pulse and subsequent re-entrainment to the new centrifugation schedule. These results provide further evidence that gravitoinertial stimuli require a functional vestibular system to both en-train and phase shift the CTS. Entrainment among only WT mice supports the role of macular gravity receptive cells in modulation of the CTS while also providing a functional mechanism by which gravitoinertial stimuli, including locomotor activity, may affect the pacemaker.

  3. Increased anxiety and fear memory in adult mice lacking type 2 deiodinase.

    PubMed

    Bárez-López, Soledad; Montero-Pedrazuela, Ana; Bosch-García, Daniel; Venero, César; Guadaño-Ferraz, Ana

    2017-10-01

    A euthyroid state in the brain is crucial for its adequate development and function. Impairments in thyroid hormones (THs; T3 or 3,5,3'-triiodothyronine and T4 or thyroxine) levels and availability in brain can lead to neurological alterations and to psychiatric disorders, particularly mood disorders. The thyroid gland synthetizes mainly T4, which is secreted to circulating blood, however, most actions of THs are mediated by T3, the transcriptionally active form. In the brain, intracellular concentrations of T3 are modulated by the activity of type 2 (D2) and type 3 (D3) deiodinases. In the present work, we evaluated learning and memory capabilities and anxiety-like behavior at adult stages in mice lacking D2 (D2KO) and we analyzed the impact of D2-deficiency on TH content and on the expression of T3-dependent genes in the amygdala and the hippocampus. We found that D2KO mice do not present impairments in spatial learning and memory, but they display emotional alterations with increased anxiety-like behavior as well as enhanced auditory-cued fear memory and spontaneous recovery of fear memory following extinction. D2KO mice also presented reduced T3 content in the hippocampus and decreased expression of the T3-dependent gene Dio3 in the amygdala suggesting a hypothyroid status in this structure. We propose that the emotional dysfunctions found in D2KO mice can arise from the reduced T3 content in their brain, which consequently leads to alterations in gene expression with functional consequences. We found a downregulation in the gene encoding for the calcium-binding protein calretinin (Calb2) in the amygdala of D2KO mice that could affect the GABAergic transmission. The current findings in D2KO mice can provide insight into emotional disorders present in humans with DIO2 polymorphisms. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Erectile dysfunction in mice lacking the large-conductance calcium-activated potassium (BK) channel

    PubMed Central

    Werner, Matthias E; Zvara, Peter; Meredith, Andrea L; Aldrich, Richard W; Nelson, Mark T

    2005-01-01

    Penile erection is dependent on the nitric oxide (NO)/cGMP-dependent protein kinase I (PKGI) pathway. One important target of PKGI in smooth muscle is the large-conductance, calcium-activated potassium (BK) channel, which upon activation hyperpolarizes the smooth muscle cell membrane, causing relaxation. Relaxation of arterial and corpus cavernosum smooth muscle (CCSM) is necessary to increase blood flow into the corpora cavernosa that leads to penile tumescence. We investigated the functional role of BK channels in the corpus cavernosum utilizing a knock-out mouse lacking the Slo gene (Slo−/−) responsible for the pore-forming subunit of the BK channel. Whole-cell currents were recorded from isolated CCSM cells of Slo+/+ and Slo−/− mice. Iberiotoxin-sensitive voltage- and [Ca2+]-activated K+ currents, the latter activated by local transient calcium releases (calcium sparks), were present in Slo+/+ CCSM cells, but absent in Slo−/− cells. CCSM strips from Slo−/− mice demonstrated a four-fold increase in phasic contractions, in the presence of phenylephrine. Nerve-evoked relaxations of precontracted strips were reduced by 50%, both in strips from Slo−/− mice and by blocking BK channels with iberiotoxin in the Slo+/+ strips. Consistent with the in vitro results, in vivo intracavernous pressure exhibited pronounced oscillations in Slo−/− mice, but not in Slo+/+ mice. Furthermore, intracavernous pressure increases to nerve stimulation, in vivo, were reduced by 22% in Slo−/−mice. These results indicate that the BK channel has an important role in erectile function, and loss of the BK channel leads to erectile dysfunction. PMID:16020453

  5. Mice lacking hippocampal left-right asymmetry show non-spatial learning deficits.

    PubMed

    Shimbo, Akihiro; Kosaki, Yutaka; Ito, Isao; Watanabe, Shigeru

    2017-08-31

    Left-right asymmetry is known to exist at several anatomical levels in the brain and recent studies have provided further evidence to show that it also exists at a molecular level in the hippocampal CA3-CA1 circuit. The distribution of N-methyl-d-aspartate (NMDA) receptor NR2B subunits in the apical and basal synapses of CA1 pyramidal neurons is asymmetrical if the input arrives from the left or right CA3 pyramidal neurons. In the present study, we examined the role of hippocampal asymmetry in cognitive function using β2-microglobulin knock-out (β2m KO) mice, which lack hippocampal asymmetry. We tested β2m KO mice in a series of spatial and non-spatial learning tasks and compared the performances of β2m KO and C57BL6/J wild-type (WT) mice. The β2m KO mice appeared normal in both spatial reference memory and spatial working memory tasks but they took more time than WT mice in learning the two non-spatial learning tasks (i.e., a differential reinforcement of lower rates of behavior (DRL) task and a straight runway task). The β2m KO mice also showed less precision in their response timing in the DRL task and showed weaker spontaneous recovery during extinction in the straight runway task. These results indicate that hippocampal asymmetry is important for certain characteristics of non-spatial learning. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Motor impairments, striatal degeneration, and altered dopamine-glutamate interplay in mice lacking PSD-95.

    PubMed

    Zhang, Jingping; Saur, Taixiang; Duke, Angela N; Grant, Seth G N; Platt, Donna M; Rowlett, James K; Isacson, Ole; Yao, Wei-Dong

    2014-01-01

    Excessive activation of the N-methyl-d-aspartate (NMDA) receptor and the neurotransmitter dopamine (DA) mediate neurotoxicity and neurodegeneration under many neurological conditions, including Huntington's disease (HD), an autosomal dominant neurodegenerative disease characterized by the preferential loss of medium spiny projection neurons (MSNs) in the striatum. PSD-95 is a major scaffolding protein in the postsynaptic density (PSD) of dendritic spines, where a classical role for PSD-95 is to stabilize glutamate receptors at sites of synaptic transmission. Our recent studies indicate that PSD-95 also interacts with the D1 DA receptor localized in spines and negatively regulates spine D1 signaling. Moreover, PSD-95 forms ternary protein complexes with D1 and NMDA receptors, and plays a role in limiting the reciprocal potentiation between both receptors from being escalated. These studies suggest a neuroprotective role for PSD-95. Here we show that mice lacking PSD-95, resulting from genetic deletion of the GK domain of PSD-95 (PSD-95-ΔGK mice), sporadically develop progressive neurological impairments characterized by hypolocomotion, limb clasping, and loss of DARPP-32-positive MSNs. Electrophysiological experiments indicated that NMDA receptors in mutant MSNs were overactive, suggested by larger, NMDA receptor-mediated miniature excitatory postsynaptic currents (EPSCs) and higher ratios of NMDA- to AMPA-mediated corticostriatal synaptic transmission. In addition, NMDA receptor currents in mutant cortical neurons were more sensitive to potentiation by the D1 receptor agonist SKF81297. Finally, repeated administration of the psychostimulant cocaine at a dose regimen not producing overt toxicity-related phenotypes in normal mice reliably converted asymptomatic mutant mice to clasping symptomatic mice. These results support the hypothesis that deletion of PSD-95 in mutant mice produces concomitant overactivation of both D1 and NMDA receptors that makes neurons more

  7. Impaired Glucose Metabolism in Mice Lacking the Tas1r3 Taste Receptor Gene.

    PubMed

    Murovets, Vladimir O; Bachmanov, Alexander A; Zolotarev, Vasiliy A

    2015-01-01

    The G-protein-coupled sweet taste receptor dimer T1R2/T1R3 is expressed in taste bud cells in the oral cavity. In recent years, its involvement in membrane glucose sensing was discovered in endocrine cells regulating glucose homeostasis. We investigated importance of extraorally expressed T1R3 taste receptor protein in age-dependent control of blood glucose homeostasis in vivo, using nonfasted mice with a targeted mutation of the Tas1r3 gene that encodes the T1R3 protein. Glucose and insulin tolerance tests, as well as behavioral tests measuring taste responses to sucrose solutions, were performed with C57BL/6ByJ (Tas1r3+/+) inbred mice bearing the wild-type allele and C57BL/6J-Tas1r3tm1Rfm mice lacking the entire Tas1r3 coding region and devoid of the T1R3 protein (Tas1r3-/-). Compared with Tas1r3+/+ mice, Tas1r3-/- mice lacked attraction to sucrose in brief-access licking tests, had diminished taste preferences for sucrose solutions in the two-bottle tests, and had reduced insulin sensitivity and tolerance to glucose administered intraperitoneally or intragastrically, which suggests that these effects are due to absence of T1R3. Impairment of glucose clearance in Tas1r3-/- mice was exacerbated with age after intraperitoneal but not intragastric administration of glucose, pointing to a compensatory role of extraoral T1R3-dependent mechanisms in offsetting age-dependent decline in regulation of glucose homeostasis. Incretin effects were similar in Tas1r3+/+ and Tas1r3-/- mice, which suggests that control of blood glucose clearance is associated with effects of extraoral T1R3 in tissues other than the gastrointestinal tract. Collectively, the obtained data demonstrate that the T1R3 receptor protein plays an important role in control of glucose homeostasis not only by regulating sugar intake but also via its extraoral function, probably in the pancreas and brain.

  8. Impaired Glucose Metabolism in Mice Lacking the Tas1r3 Taste Receptor Gene

    PubMed Central

    2015-01-01

    The G-protein-coupled sweet taste receptor dimer T1R2/T1R3 is expressed in taste bud cells in the oral cavity. In recent years, its involvement in membrane glucose sensing was discovered in endocrine cells regulating glucose homeostasis. We investigated importance of extraorally expressed T1R3 taste receptor protein in age-dependent control of blood glucose homeostasis in vivo, using nonfasted mice with a targeted mutation of the Tas1r3 gene that encodes the T1R3 protein. Glucose and insulin tolerance tests, as well as behavioral tests measuring taste responses to sucrose solutions, were performed with C57BL/6ByJ (Tas1r3+/+) inbred mice bearing the wild-type allele and C57BL/6J-Tas1r3tm1Rfm mice lacking the entire Tas1r3 coding region and devoid of the T1R3 protein (Tas1r3-/-). Compared with Tas1r3+/+ mice, Tas1r3-/- mice lacked attraction to sucrose in brief-access licking tests, had diminished taste preferences for sucrose solutions in the two-bottle tests, and had reduced insulin sensitivity and tolerance to glucose administered intraperitoneally or intragastrically, which suggests that these effects are due to absence of T1R3. Impairment of glucose clearance in Tas1r3-/- mice was exacerbated with age after intraperitoneal but not intragastric administration of glucose, pointing to a compensatory role of extraoral T1R3-dependent mechanisms in offsetting age-dependent decline in regulation of glucose homeostasis. Incretin effects were similar in Tas1r3+/+ and Tas1r3-/- mice, which suggests that control of blood glucose clearance is associated with effects of extraoral T1R3 in tissues other than the gastrointestinal tract. Collectively, the obtained data demonstrate that the T1R3 receptor protein plays an important role in control of glucose homeostasis not only by regulating sugar intake but also via its extraoral function, probably in the pancreas and brain. PMID:26107521

  9. Potencies of red seabream AHR1- and AHR2-mediated transactivation by dioxins: implication of both AHRs in dioxin toxicity.

    PubMed

    Bak, Su-Min; Iida, Midori; Hirano, Masashi; Iwata, Hisato; Kim, Eun-Young

    2013-03-19

    To evaluate species- and isoform-specific responses to dioxins and related compounds (DRCs) via aryl hydrocarbon receptor (AHR) in the red seabream ( Pagrus major ), we constructed a reporter gene assay system. Each expression plasmid of red seabream AHR1 (rsAHR1) and AHR2 (rsAHR2) together with a reporter plasmid containing red seabream CYP1A 5'-flanking region were transfected into COS-7 cells. The cells were treated with graded concentrations of seven DRC congeners including 2,3,7,8-TCDD, 1,2,3,7,8-PeCDD, 1,2,3,4,7,8-HxCDD, 2,3,7,8-TCDF, 2,3,4,7,8-PeCDF, 1,2,3,4,7,8-HxCDF, and PCB126. Both rsAHR1 and rsAHR2 exhibited dose-dependent responses for all the tested congeners. The rsAHR isoform-specific TCDD induction equivalency factors (rsAHR1- and rsAHR2-IEFs) were calculated on the basis of 2,3,7,8-TCDD relative potency derived from the dose-response of each congener. The rsAHR1-IEFs of PeCDD, HxCDD, TCDF, PeCDF, and HxCDF were estimated as 0.17, 0.29, 2.5, 1.5, and 0.27, respectively. For PCB126, no rsAHR1-IEF was given because of less than 10% 2,3,7,8-TCDD maximum response. The rsAHR2-IEFs of PeCDD, HxCDD, TCDF, PeCDF, HxCDF, and PCB126 were estimated as 0.38, 0.13, 1.5, 0.93, 0.20, and 0.0085, respectively. The rsAHR1/2-IEF profiles were different from WHO toxic equivalency factors for fish. In silico docking simulations supported that both rsAHRs have potentials to bind to these congeners. These results suggest that dioxin toxicities may be mediated by both rsAHRs in red seabreams.

  10. Spontaneous excretion of D-alanine in urine in mutant mice lacking D-amino-acid oxidase.

    PubMed Central

    Konno, R; Nagata, Y; Niwa, A; Yasumura, Y

    1989-01-01

    Urine from mutant mice lacking D-amino-acid oxidase contained a large amount of alanine compared with that from normal mice. Urinary alanine of the mutant mice was sensitive to D-amino-acid oxidase. H.p.l.c. showed that about 94% of the urinary alanine had the D-configuration. These results suggest that D-amino-acid oxidase functions to decompose D-amino acid(s) in normal mice. Images Fig. 1. PMID:2570568

  11. Mice lacking Axl and Mer tyrosine kinase receptors are susceptible to experimental autoimmune orchitis induction.

    PubMed

    Li, Nan; Liu, Zhenghui; Zhang, Yue; Chen, Qiaoyuan; Liu, Peng; Cheng, C Yan; Lee, Will M; Chen, Yongmei; Han, Daishu

    2015-03-01

    The mammalian testis is an immunoprivileged organ where male germ cell autoantigens are immunologically ignored. Both systemic immune tolerance to autoantigens and local immunosuppressive milieu contribute to the testicular immune privilege. Testicular immunosuppression has been intensively studied, but information on systemic immune tolerance to autoantigens is lacking. In the present study, we aimed to determine the role of Axl and Mer receptor tyrosine kinases in maintaining the systemic tolerance to male germ cell antigens using the experimental autoimmune orchitis (EAO) model. Axl and Mer double-knockout (Axl(-/-)Mer(-/-)) mice developed evident EAO after a single immunization with germ cell homogenates emulsified with complete Freund's adjuvant. EAO was characterized by the accumulation of macrophages and T lymphocytes in the testis. Damage to the seminiferous epithelium was also observed. EAO induction was associated with pro-inflammatory cytokine upregulation in the testes, impaired permeability of the blood-testis barrier and generation of autoantibodies against germ cell antigens in Axl(-/-)Mer(-/-) mice. Immunization also induced mild EAO in Axl or Mer single-gene-knockout mice. By contrast, a single immunization failed to induce EAO in wild-type mice. The results indicate that Axl and Mer receptors cooperatively regulate the systemic immune tolerance to male germ cell antigens.

  12. Impaired Hair Growth and Wound Healing in Mice Lacking Thyroid Hormone Receptors

    PubMed Central

    Martínez-Fernández, Mónica; Ruiz-Llorente, Lidia; Paramio, Jesus M.; Aranda, Ana

    2014-01-01

    Both clinical and experimental observations show that the skin is affected by the thyroidal status. In hypothyroid patients the epidermis is thin and alopecia is common, indicating that thyroidal status might influence not only skin proliferation but also hair growth. We demonstrate here that the thyroid hormone receptors (TRs) mediate these effects of the thyroid hormones on the skin. Mice lacking TRα1 and TRβ (the main thyroid hormone binding isoforms) display impaired hair cycling associated to a decrease in follicular hair cell proliferation. This was also observed in hypothyroid mice, indicating the important role of the hormone-bound receptors in hair growth. In contrast, the individual deletion of either TRα1 or TRβ did not impair hair cycling, revealing an overlapping or compensatory role of the receptors in follicular cell proliferation. In support of the role of the receptors in hair growth, TRα1/TRβ-deficient mice developed alopecia after serial depilation. These mice also presented a wound-healing defect, with retarded re-epithelialization and wound gaping, associated to impaired keratinocyte proliferation. These results reinforce the idea that the thyroid hormone nuclear receptors play an important role on skin homeostasis and suggest that they could be targets for the treatment of cutaneous pathologies. PMID:25254665

  13. Defective prohormone processing and altered pancreatic islet morphology in mice lacking active SPC2

    PubMed Central

    Furuta, Machi; Yano, Hideki; Zhou, An; Rouillé, Yves; Holst, Jens J.; Carroll, Raymond; Ravazzola, Mariella; Orci, Lelio; Furuta, Hiroto; Steiner, Donald F.

    1997-01-01

    The prohormone convertase SPC2 (PC2) participates in the processing of proinsulin, proglucagon, and a variety of other neuroendocrine precursors, acting either alone or in conjunction with the structurally related dense-core granule convertase SPC3 (PC3/PC1). We have generated a strain of mice lacking active SPC2 by introducing the neomycin resistance gene (Neor) into the third exon of the mSPC2 gene. This gene insertion results in the synthesis of an exon 3-deleted form of SPC2 that does not undergo autoactivation and is not secreted. The homozygous mutant mice appear to be normal at birth. However, they exhibit a small decrease in rate of growth. They also have chronic fasting hypoglycemia and a reduced rise in blood glucose levels during an intraperitoneal glucose tolerance test, which is consistent with a deficiency of circulating glucagon. The processing of proglucagon, prosomatostatin, and proinsulin in the alpha, delta, and beta cells, respectively, of the pancreatic islets is severely impaired. The islets in mutant mice at 3 months of age show marked hyperplasia of alpha and delta cells and a relative diminution of beta cells. SPC2-defective mice offer many possibilities for further delineating neuroendocrine precursor processing mechanisms and for exploring more fully the physiological roles of many neuropeptides and peptide hormones. PMID:9192619

  14. Impaired hair growth and wound healing in mice lacking thyroid hormone receptors.

    PubMed

    Contreras-Jurado, Constanza; García-Serrano, Laura; Martínez-Fernández, Mónica; Ruiz-Llorente, Lidia; Paramio, Jesus M; Aranda, Ana

    2014-01-01

    Both clinical and experimental observations show that the skin is affected by the thyroidal status. In hypothyroid patients the epidermis is thin and alopecia is common, indicating that thyroidal status might influence not only skin proliferation but also hair growth. We demonstrate here that the thyroid hormone receptors (TRs) mediate these effects of the thyroid hormones on the skin. Mice lacking TRα1 and TRβ (the main thyroid hormone binding isoforms) display impaired hair cycling associated to a decrease in follicular hair cell proliferation. This was also observed in hypothyroid mice, indicating the important role of the hormone-bound receptors in hair growth. In contrast, the individual deletion of either TRα1 or TRβ did not impair hair cycling, revealing an overlapping or compensatory role of the receptors in follicular cell proliferation. In support of the role of the receptors in hair growth, TRα1/TRβ-deficient mice developed alopecia after serial depilation. These mice also presented a wound-healing defect, with retarded re-epithelialization and wound gaping, associated to impaired keratinocyte proliferation. These results reinforce the idea that the thyroid hormone nuclear receptors play an important role on skin homeostasis and suggest that they could be targets for the treatment of cutaneous pathologies.

  15. Cocaine supersensitivity and enhanced motivation for reward in mice lacking dopamine D2 autoreceptors

    PubMed Central

    Bello, Estefanía P; Mateo, Yolanda; Gelman, Diego M; Noaín, Daniela; Shin, Jung H; Low, Malcolm J; Alvarez, Verónica A; Lovinger, David M; Rubinstein, Marcelo

    2011-01-01

    Dopamine (DA) D2 receptors expressed in DA neurons (D2 autoreceptors) exert a negative feedback regulation that reduces DA neuron firing, DA synthesis and DA release. As D2 receptors are mostly expressed in postsynaptic neurons, pharmacological and genetic approaches have been unable to definitively address the in vivo contribution of D2 autoreceptors to DA-mediated behaviors. We found that midbrain DA neurons from mice deficient in D2 autoreceptors (Drd2loxP/loxP; Dat+/IRES-cre, referred to as autoDrd2KO mice) lacked DA-mediated somatodendritic synaptic responses and inhibition of DA release. AutoDrd2KO mice displayed elevated DA synthesis and release, hyperlocomotion and supersensitivity to the psychomotor effects of cocaine. The mice also exhibited increased place preference for cocaine and enhanced motivation for food reward. Our results highlight the importance of D2 autoreceptors in the regulation of DA neurotransmission and demonstrate that D2 autoreceptors are important for normal motor function, food-seeking behavior, and sensitivity to the locomotor and rewarding properties of cocaine. PMID:21743470

  16. Lack of effect of anticonvulsant topiramate on methamphetamine-induced stereotypy and rewarding property in mice.

    PubMed

    Tatsuta, Tomohiro; Kitanaka, Nobue; Kitanaka, Junichi; Morita, Yoshio; Takemura, Motohiko

    2007-05-01

    The effects of topiramate, a structurally novel anticonvulsant, on the methamphetamine (METH)-induced expression of stereotypy and conditioned place preference (CPP) in male ICR mice were investigated. After a single administration of METH (10 mg/kg, i.p.), mice showed stereotyped behaviors with a plateau level 25 min after drug challenge. Pretreatment with topiramate (1, 10, and 100 mg/kg, i.p.) 30 min prior to METH challenge had no effect on the expression frequency of stereotypy, compared with saline challenge. No differential effects of topiramate on METH-induced stereotyped behavior (that is, head-bobbing, circling, continuous sniffing, nail and/or wood-chip biting, and vigorous and compulsive grooming) were observed. In saline-challenged groups, the doses of topiramate examined did not induce any stereotyped behaviors. Although mice showed a significant CPP for METH (0.5 mg/kg, i.p.), pretreatment with subchronic topiramate did not affect the magnitude of CPP. Locomotor activity was not affected by the doses of topiramate tested. Conditioned rewarding or aversive effects of topiramate were not observed as indexed by the place preference procedure. These results suggested the lack of effect of topiramate on METH-induced stereotypy and rewarding property in mice.

  17. Decreased tumorigenesis and mortality from bladder cancer in mice lacking urothelial androgen receptor.

    PubMed

    Hsu, Jong-Wei; Hsu, Iawen; Xu, Defeng; Miyamoto, Hiroshi; Liang, Liang; Wu, Xue-Ru; Shyr, Chih-Rong; Chang, Chawnshang

    2013-05-01

    Much fewer mice lacking androgen receptor (AR) in the entire body develop bladder cancer (BCa). However, the role of urothelial AR (Uro-AR) in BCa development remains unclear. In the present study, we generated mice that lacked only Uro-AR (Uro-AR(-/y)) to develop BCa by using the carcinogen BBN [N-butyl-N-(4-hydroxybutyl)-nitrosamine] and found that Uro-AR(-/y) mice had a lower incidence of BCa and a higher survival rate than did their wild-type (WT; Uro-AR(+/y)) littermates. In vitro assay also demonstrated that Uro-AR facilitates the neoplastic transformation of normal urothelial cells to carcinoma. IHC staining exhibited less DNA damage, with much higher expression of p53 and its downstream target protein PNCA in Uro-AR(-/y) than that found in WT urothelium, which suggests that Uro-AR may modulate bladder tumorigenesis through p53-PCNA DNA repair signaling. Indeed, Uro-AR(-/y) mice with the transgene, simian vacuolating virus 40 T (SV40T), in the urothelium (Uro-SV40T-AR(-/y)) had a similar incidence of BCa as did their WT littermates (Uro-SV40T-AR(+/y)), and p53 was inactivated by SV40T in both genotypes. Use of the AR degradation enhancer ASC-J9 led to suppression of bladder tumorigenesis, with few adverse effects in the BBN-induced BCa mouse model. Together, these results provide the first direct in vivo evidence that Uro-AR has an important role in promoting bladder tumorigenesis and BCa progression. Targeting AR with ASC-J9 may provide a novel approach to suppress BCa initiation.

  18. Resilient emotionality and molecular compensation in mice lacking the oligodendrocyte-specific gene Cnp1.

    PubMed

    Edgar, N M; Touma, C; Palme, R; Sibille, E

    2011-09-20

    Altered oligodendrocyte structure and function is implicated in major psychiatric illnesses, including low cell number and reduced oligodendrocyte-specific gene expression in major depressive disorder (MDD). These features are also observed in the unpredictable chronic mild stress (UCMS) rodent model of the illness, suggesting that they are consequential to environmental precipitants; however, whether oligodendrocyte changes contribute causally to low emotionality is unknown. Focusing on 2'-3'-cyclic nucleotide 3'-phosphodiesterase (Cnp1), a crucial component of axoglial communication dysregulated in the amygdala of MDD subjects and UCMS-exposed mice, we show that altered oligodendrocyte integrity can have an unexpected functional role in affect regulation. Mice lacking Cnp1 (knockout, KO) displayed decreased anxiety- and depressive-like symptoms (i.e., low emotionality) compared with wild-type animals, a phenotypic difference that increased with age (3-9 months). This phenotype was accompanied by increased motor activity, but was evident before neurodegenerative-associated motor coordination deficits (≤ 9-12 months). Notably, Cnp1(KO) mice were less vulnerable to developing a depressive-like syndrome after either UCMS or chronic corticosterone exposure. Cnp1(KO) mice also displayed reduced fear expression during extinction, despite normal amygdala c-Fos induction after acute stress, together implicating dysfunction of an amygdala-related neural network, and consistent with proposed mechanisms for stress resiliency. However, the Cnp1(KO) behavioral phenotype was also accompanied by massive upregulation of oligodendrocyte- and immune-related genes in the basolateral amygdala, suggesting an attempt at functional compensation. Together, we demonstrate that the lack of oligodendrocyte-specific Cnp1 leads to resilient emotionality. However, combined with substantial molecular changes and late-onset neurodegeneration, these results suggest the low Cnp1 seen in MDD may

  19. Taste responses in mice lacking taste receptor subunit T1R1

    PubMed Central

    Kusuhara, Yoko; Yoshida, Ryusuke; Ohkuri, Tadahiro; Yasumatsu, Keiko; Voigt, Anja; Hübner, Sandra; Maeda, Katsumasa; Boehm, Ulrich; Meyerhof, Wolfgang; Ninomiya, Yuzo

    2013-01-01

    The T1R1 receptor subunit acts as an umami taste receptor in combination with its partner, T1R3. In addition, metabotropic glutamate receptors (brain and taste variants of mGluR1 and mGluR4) are thought to function as umami taste receptors. To elucidate the function of T1R1 and the contribution of mGluRs to umami taste detection in vivo, we used newly developed knock-out (T1R1−/−) mice, which lack the entire coding region of the Tas1r1 gene and express mCherry in T1R1-expressing cells. Gustatory nerve recordings demonstrated that T1R1−/− mice exhibited a serious deficit in inosine monophosphate-elicited synergy but substantial residual responses to glutamate alone in both chorda tympani and glossopharyngeal nerves. Interestingly, chorda tympani nerve responses to sweeteners were smaller in T1R1−/− mice. Taste cell recordings demonstrated that many mCherry-expressing taste cells in T1R1+/− mice responded to sweet and umami compounds, whereas those in T1R1−/− mice responded to sweet stimuli. The proportion of sweet-responsive cells was smaller in T1R1−/− than in T1R1+/− mice. Single-cell RT-PCR demonstrated that some single mCherry-expressing cells expressed all three T1R subunits. Chorda tympani and glossopharyngeal nerve responses to glutamate were significantly inhibited by addition of mGluR antagonists in both T1R1−/− and T1R1+/− mice. Conditioned taste aversion tests demonstrated that both T1R1−/− and T1R1+/− mice were equally capable of discriminating glutamate from other basic taste stimuli. Avoidance conditioned to glutamate was significantly reduced by addition of mGluR antagonists. These results suggest that T1R1-expressing cells mainly contribute to umami taste synergism and partly to sweet sensitivity and that mGluRs are involved in the detection of umami compounds. PMID:23339178

  20. Gastrointestinal Mucins of Fut2-Null Mice Lack Terminal Fucosylation without Affecting Colonization by Candida albicans

    PubMed Central

    Hurd, Elizabeth A.; Holmén, Jessica M.; Hansson, Gunnar C.; Domino, Steven E.

    2006-01-01

    Post-translational modification of apomucins by the sequential action of glycosyltransferases is required to produce mature mucins. The “Secretor” gene (FUT2) encodes an α(1,2)fucosyltransferase (E.C. 2.4.1.69) that catalyzes addition of terminal α(1,2)fucose residues on mucins and other molecules in mucosal epithelium. Mutant mice containing targeted replacement of Fut2 with the bacterial reporter gene lacZ were studied to determine the affect of the loss of Fut2 on glycosylation of mucins in the gastrointestinal tract. By whole organ X-gal staining, lacZ activity is prominently expressed in the foveolar pit and chief cells of the glandular stomach, Brunner's glands of the duodenum, and goblet cells in the large intestine of Fut2-LacZ null mice. Staining with Aleuria aurantia agglutinin demonstrates loss of l-fucosylated epithelial glycans throughout the gastrointestinal tract of Fut2-LacZ null mice, however, histologic appearance of the tissues appears normal. Analysis of oligosaccharides released from insoluble colonic mucins, largely Muc2, by mass spectrometry shows complete lack of terminal fucosylation of O-linked oligosaccharides in Fut2-LacZ null mice. Precursor glycans accumulate with no evidence of compensation by other fucosyltransferases or sialyltransferases on mucin glycosylation. Since Candida albicans has been reported to adhere to intestinal mucins creating a potential reservoir associated with vaginitis, Fut2-LacZ null and wild type mice were inoculated by gastric lavage with C. albicans. We observe no difference in colonization between genotypes suggesting mucin terminal fucosylation does not significantly influence C. albicans-host interaction in the intestine, highlighting that infections caused by the same organism at different mucosal surfaces are not equal. PMID:15958416

  1. Female mice lacking estrogen receptor-alpha in osteoblasts have compromised bone mass and strength.

    PubMed

    Melville, Katherine M; Kelly, Natalie H; Khan, Sohaib A; Schimenti, John C; Ross, F Patrick; Main, Russell P; van der Meulen, Marjolein C H

    2014-02-01

    Reduced bioavailability of estrogen increases skeletal fracture risk in postmenopausal women, but the mechanisms by which estrogen regulates bone mass are incompletely understood. Because estrogen signaling in bone acts, in part, through estrogen receptor alpha (ERα), mice with global deletion of ERα (ERαKO) have been used to determine the role of estrogen signaling in bone biology. These animals, however, have confounding systemic effects arising from other organs, such as increased estrogen and decreased insulin-like growth factor 1 (IGF-1) serum levels, which may independently affect bone. Mice with tissue-specific ERα deletion in chondrocytes, osteoblasts, osteocytes, or osteoclasts lack the systemic effects seen in the global knockout, but show that presence of the receptor is important for the function of each cell type. Although bone mass is reduced when ERα is deleted from osteoblasts, no study has determined if this approach reduces whole bone strength. To address this issue, we generated female osteoblast-specific ERαKO mice (pOC-ERαKO) by crossing mice expressing a floxed ERα gene (ERα(fl/fl)) with mice transgenic for the osteocalcin-Cre promoter (OC-Cre). Having confirmed that serum levels of estrogen and IGF-1 were unaltered, we focused on relating bone mechanics to skeletal phenotype using whole bone mechanical testing, microcomputed tomography, histology, and dynamic histomorphometry. At 12 and 18 weeks of age, pOC-ERαKO mice had decreased cancellous bone mass in the proximal tibia, vertebra, and distal femur, and decreased cortical bone mass in the tibial midshaft, distal femoral cortex, and L5 vertebral cortex. Osteoblast activity was reduced in cancellous bone of the proximal tibia, but osteoclast number was unaffected. Both femora and vertebrae had decreased whole bone strength in mechanical tests to failure, indicating that ERα in osteoblasts is required for appropriate bone mass and strength accrual in female mice. This p

  2. Dopamine pathway imbalance in mice lacking Magel2, a Prader-Willi syndrome candidate gene.

    PubMed

    Luck, Chloe; Vitaterna, Martha H; Wevrick, Rachel

    2016-08-01

    The etiology of abnormal eating behaviors, including binge-eating disorder, is poorly understood. The neural circuits modulating the activities of the neurotransmitters dopamine and serotonin are proposed to be dysfunctional in individuals suffering from eating disorders. Prader-Willi syndrome is a neurodevelopmental disorder that causes extreme food seeking and binge-eating behaviors together with reduced satiety. One of the genes implicated in Prader-Willi syndrome, Magel2, is highly expressed in the regions of the brain that control appetite. Our objective was to examine behaviors relevant to feeding and the neural circuits controlling feeding in a mouse model of Prader-Willi syndrome that lacks expression of the Magel2 gene. We performed behavioral tests related to dopaminergic function, measuring cocaine-induced hyperlocomotion, binge eating, and saccharin-induced anhedonia in Magel2-deficient mice. Next, we analyzed dopaminergic neurons in various brain regions and compared these findings between genotypes. Finally, we examined biochemical markers in the brain under standard diet, high-fat diet, and withdrawal from a high-fat diet conditions. We identified abnormal behaviors and biomarkers reflecting dopaminergic dysfunction in mice lacking Magel2. Our results provide a biological framework for clinical studies of dopaminergic function in children with Prader-Willi syndrome, and may also provide insight into binge-eating disorders that occur in the general population. (PsycINFO Database Record

  3. Nerve growth factor evokes hyperalgesia in mice lacking the low-affinity neurotrophin receptor p75.

    PubMed

    Bergmann, I; Reiter, R; Toyka, K V; Koltzenburg, M

    1998-10-16

    Endogenous nerve growth factor (NGF) has been shown to be an important mediator of inflammatory pain and exogenous application of recombinant human NGF (rhNGF) produces pain and hyperalgesia in animals and humans. Since NGF can act through two receptors types, the high affinity tyrosine kinase A (trkA) receptor and the low affinity p75 receptor, we used transgenic mice lacking p75 to analyse the relative importance of these receptors. After systemic injection of rhNGF (5 mg/ kg), pharmacokinetic studies revealed similar serum levels and elimination profiles of exogenously administered rhNGF in both strains of mice. Although animals lacking p75 have increased mechanical and thermal withdrawal thresholds they developed both heat and mechanical hyperalgesia after systemic injection of rhNGF whose magnitude did not differ significantly from wildtype animals. This means that NGF-induced hyperalgesia can occur in the absence of the p75 receptor and suggests that the trkA receptor is sufficient to mediate the acute noxious action of NGF.

  4. Golgi Disruption and Early Embryonic Lethality in Mice Lacking USO1

    PubMed Central

    Kim, Susie; Hill, Adele; Warman, Matthew L.; Smits, Patrick

    2012-01-01

    Golgins are a family of long rod-like proteins characterized by the presence of central coiled-coil domains. Members of the golgin family have important roles in membrane trafficking, where they function as tethering factors that capture transport vesicles and facilitate membrane fusion. Golgin family members also have essential roles in maintaining the organization of the Golgi apparatus. Knockdown of individual golgins in cultured cells resulted in the disruption of the Golgi structure and the dispersal of Golgi marker proteins throughout the cytoplasm. However, these cellular phenotypes have not always been recapitulated in vivo. For example, embryonic development proceeds much further than expected and Golgi disruption was observed in only a subset of cell types in mice lacking the ubiquitously expressed golgin GMAP-210. Cell-type specific functional compensation among golgins may explain the absence of global cell lethality when a ubiquitously expressed golgin is missing. In this study we show that functional compensation does not occur for the golgin USO1. Mice lacking this ubiquitously expressed protein exhibit disruption of Golgi structure and early embryonic lethality, indicating that USO1 is indispensable for early embryonic development. PMID:23185636

  5. Distal renal tubular acidosis in mice that lack the forkhead transcription factor Foxi1

    PubMed Central

    Blomqvist, Sandra Rodrigo; Vidarsson, Hilmar; Fitzgerald, Sharyn; Johansson, Bengt R.; Ollerstam, Anna; Brown, Russell; Persson, A. Erik G.; Bergström, Göran; Enerbäck, Sven

    2004-01-01

    While macro- and microscopic kidney development appear to proceed normally in mice that lack Foxi1, electron microscopy reveals an altered ultrastructure of cells lining the distal nephron. Northern blot analyses, cRNA in situ hybridizations, and immunohistochemistry demonstrate a complete loss of expression of several anion transporters, proton pumps, and anion exchange proteins expressed by intercalated cells of the collecting ducts, many of which have been implicated in hereditary forms of distal renal tubular acidosis (dRTA). In Foxi1-null mutants the normal epithelium with its two major cell types — principal and intercalated cells — has been replaced by a single cell type positive for both principal and intercalated cell markers. To test the functional consequences of these alterations, Foxi1–/– mice were compared with WT littermates in their response to an acidic load. This revealed an inability to acidify the urine as well as a lowered systemic buffer capacity and overt acidosis in null mutants. Thus, Foxi1–/– mice seem to develop dRTA due to altered cellular composition of the distal nephron epithelium, thereby denying this epithelium the proper gene expression pattern needed for maintaining adequate acid-base homeostasis. PMID:15173882

  6. Severely impaired learning and altered neuronal morphology in mice lacking NMDA receptors in medium spiny neurons.

    PubMed

    Beutler, Lisa R; Eldred, Kiara C; Quintana, Albert; Keene, C Dirk; Rose, Shannon E; Postupna, Nadia; Montine, Thomas J; Palmiter, Richard D

    2011-01-01

    The striatum is composed predominantly of medium spiny neurons (MSNs) that integrate excitatory, glutamatergic inputs from the cortex and thalamus, and modulatory dopaminergic inputs from the ventral midbrain to influence behavior. Glutamatergic activation of AMPA, NMDA, and metabotropic receptors on MSNs is important for striatal development and function, but the roles of each of these receptor classes remain incompletely understood. Signaling through NMDA-type glutamate receptors (NMDARs) in the striatum has been implicated in various motor and appetitive learning paradigms. In addition, signaling through NMDARs influences neuronal morphology, which could underlie their role in mediating learned behaviors. To study the role of NMDARs on MSNs in learning and in morphological development, we generated mice lacking the essential NR1 subunit, encoded by the Grin1 gene, selectively in MSNs. Although these knockout mice appear normal and display normal 24-hour locomotion, they have severe deficits in motor learning, operant conditioning and active avoidance. In addition, the MSNs from these knockout mice have smaller cell bodies and decreased dendritic length compared to littermate controls. We conclude that NMDAR signaling in MSNs is critical for normal MSN morphology and many forms of learning.

  7. Growth retardation and abnormal maternal behavior in mice lacking testicular orphan nuclear receptor 4

    PubMed Central

    Collins, Loretta L.; Lee, Yi-Fen; Heinlein, Cynthia A.; Liu, Ning-Chun; Chen, Yei-Tsung; Shyr, Chih-Rong; Meshul, Charles K.; Uno, Hideo; Platt, Kenneth A.; Chang, Chawnshang

    2004-01-01

    Testicular orphan nuclear receptor 4 (TR4) is a member of the nuclear receptor superfamily for which a ligand has not yet been found. In vitro data obtained from various cell lines suggest that TR4 functions as a master regulator to modulate many signaling pathways, yet the in vivo physiological roles of TR4 remain unclear. Here, we report the generation of mice lacking TR4 by means of targeted gene disruption (TR4–/–). The number of TR4–/– pups generated by the mating of TR4+/– mice is well under that predicted by the normal Mendelian ratio, and TR4–/– mice demonstrate high rates of early postnatal mortality, as well as significant growth retardation. Additionally, TR4–/– females show defects in reproduction and maternal behavior, with pups of TR4–/– dams dying soon after birth with no indication of milk intake. These results provide in vivo evidence that TR4 plays important roles in growth, embryonic and early postnatal pup survival, female reproductive function, and maternal behavior. PMID:15477591

  8. Female mice lacking Xist RNA show partial dosage compensation and survive to term

    PubMed Central

    Yang, Lin; Kirby, James E.; Sunwoo, Hongjae; Lee, Jeannie T.

    2016-01-01

    X-chromosome inactivation (XCI) compensates for differences in X-chromosome number between male and female mammals. XCI is orchestrated by Xist RNA, whose expression in early development leads to transcriptional silencing of one X chromosome in the female. Knockout studies have established a requirement for Xist with inviability of female embryos that inherit an Xist deletion from the father. Here, we report that female mice lacking Xist RNA can, surprisingly, develop and survive to term. Xist-null females are born at lower frequency and are smaller at birth, but organogenesis is mostly normal. Transcriptomic analysis indicates significant overexpression of hundreds of X-linked genes across multiple tissues. Therefore, Xist-null mice can develop to term in spite of a deficiency of dosage compensation. However, the degree of X-autosomal dosage imbalance was less than anticipated (1.14-fold to 1.36-fold). Thus, partial dosage compensation can be achieved without Xist, supporting the idea of inherent genome balance. Nevertheless, to date, none of the mutant mice has survived beyond weaning stage. Sudden death is associated with failure of postnatal organ maturation. Our data suggest Xist-independent mechanisms of dosage compensation and demonstrate that small deviations from X-autosomal balance can have profound effects on overall fitness. PMID:27542829

  9. Folate deficiency induces neurodegeneration and brain dysfunction in mice lacking uracil DNA glycosylase.

    PubMed

    Kronenberg, Golo; Harms, Christoph; Sobol, Robert W; Cardozo-Pelaez, Fernando; Linhart, Heinz; Winter, Benjamin; Balkaya, Mustafa; Gertz, Karen; Gay, Shanna B; Cox, David; Eckart, Sarah; Ahmadi, Michael; Juckel, Georg; Kempermann, Gerd; Hellweg, Rainer; Sohr, Reinhard; Hörtnagl, Heide; Wilson, Samuel H; Jaenisch, Rudolf; Endres, Matthias

    2008-07-09

    Folate deficiency and resultant increased homocysteine levels have been linked experimentally and epidemiologically with neurodegenerative conditions like stroke and dementia. Moreover, folate deficiency has been implicated in the pathogenesis of psychiatric disorders, most notably depression. We hypothesized that the pathogenic mechanisms include uracil misincorporation and, therefore, analyzed the effects of folate deficiency in mice lacking uracil DNA glycosylase (Ung-/-) versus wild-type controls. Folate depletion increased nuclear mutation rates in Ung-/- embryonic fibroblasts, and conferred death of cultured Ung-/- hippocampal neurons. Feeding animals a folate-deficient diet (FD) for 3 months induced degeneration of CA3 pyramidal neurons in Ung-/- but not Ung+/+ mice along with decreased hippocampal expression of brain-derived neurotrophic factor protein and decreased brain levels of antioxidant glutathione. Furthermore, FD induced cognitive deficits and mood alterations such as anxious and despair-like behaviors that were aggravated in Ung-/- mice. Independent of Ung genotype, FD increased plasma homocysteine levels, altered brain monoamine metabolism, and inhibited adult hippocampal neurogenesis. These results indicate that impaired uracil repair is involved in neurodegeneration and neuropsychiatric dysfunction induced by experimental folate deficiency.

  10. Persistence of diet-induced obesity despite access to voluntary activity in mice lacking sarcolipin.

    PubMed

    Gamu, Daniel; Trinh, Anton; Bombardier, Eric; Tupling, A Russell

    2015-09-01

    Several rodent models of obesity have been shown to develop excessive adiposity only when voluntary cage ambulation is restricted. We have previously shown that mice lacking the sarco(endo)plasmic reticulum Ca(2+)-ATPase pump regulatory protein sarcolipin (Sln(-/-)), an uncoupler of Ca(2+) uptake, develop excessive diet-induced obesity under standard housing conditions. However, it is unclear whether this phenotype is due, in part, to the sedentary housing environment in which these animals are kept. To address this, we allowed wild-type and Sln(-/-) animals ad libitum access to voluntary wheel running while consuming a standard chow or high-fat diet for 8 weeks. During this period, wheel revolutions were monitored along with weekly mass gain. Postdiet glucose tolerance and visceral adiposity were also taken. The volume of wheel running completed was similar between genotype, regardless of diet. Although voluntary activity reduced mass gain relative to sedentary controls within each diet (P < 0.05), visceral adiposity was surprisingly unaltered with activity. However, Sln(-/-) mice developed excessive obesity (P < 0.05) and glucose intolerance (P < 0.05) with high-fat feeding relative to wild-type controls. These findings indicate that the excessive diet-induced obese phenotype previously observed in Sln(-/-) mice is not the result of severely restricted daily ambulation, but in fact the inability to recruit uncoupling of the Ca(2+)-ATPase pump.

  11. Calcium-activated chloride currents in olfactory sensory neurons from mice lacking bestrophin-2.

    PubMed

    Pifferi, Simone; Dibattista, Michele; Sagheddu, Claudia; Boccaccio, Anna; Al Qteishat, Ahmed; Ghirardi, Filippo; Tirindelli, Roberto; Menini, Anna

    2009-09-01

    Olfactory sensory neurons use a chloride-based signal amplification mechanism to detect odorants. The binding of odorants to receptors in the cilia of olfactory sensory neurons activates a transduction cascade that involves the opening of cyclic nucleotide-gated channels and the entry of Ca(2+) into the cilia. Ca(2+) activates a Cl(-) current that produces an efflux of Cl(-) ions and amplifies the depolarization. The molecular identity of Ca(2+)-activated Cl(-) channels is still elusive, although some bestrophins have been shown to function as Ca(2+)-activated Cl(-) channels when expressed in heterologous systems. In the olfactory epithelium, bestrophin-2 (Best2) has been indicated as a candidate for being a molecular component of the olfactory Ca(2+)-activated Cl(-) channel. In this study, we have analysed mice lacking Best2. We compared the electrophysiological responses of the olfactory epithelium to odorant stimulation, as well as the properties of Ca(2+)-activated Cl(-) currents in wild-type (WT) and knockout (KO) mice for Best2. Our results confirm that Best2 is expressed in the cilia of olfactory sensory neurons, while odorant responses and Ca(2+)-activated Cl(-) currents were not significantly different between WT and KO mice. Thus, Best2 does not appear to be the main molecular component of the olfactory channel. Further studies are required to determine the function of Best2 in the cilia of olfactory sensory neurons.

  12. Calcium-activated chloride currents in olfactory sensory neurons from mice lacking bestrophin-2

    PubMed Central

    Pifferi, Simone; Dibattista, Michele; Sagheddu, Claudia; Boccaccio, Anna; Al Qteishat, Ahmed; Ghirardi, Filippo; Tirindelli, Roberto; Menini, Anna

    2009-01-01

    Olfactory sensory neurons use a chloride-based signal amplification mechanism to detect odorants. The binding of odorants to receptors in the cilia of olfactory sensory neurons activates a transduction cascade that involves the opening of cyclic nucleotide-gated channels and the entry of Ca2+ into the cilia. Ca2+ activates a Cl− current that produces an efflux of Cl− ions and amplifies the depolarization. The molecular identity of Ca2+-activated Cl− channels is still elusive, although some bestrophins have been shown to function as Ca2+-activated Cl− channels when expressed in heterologous systems. In the olfactory epithelium, bestrophin-2 (Best2) has been indicated as a candidate for being a molecular component of the olfactory Ca2+-activated Cl− channel. In this study, we have analysed mice lacking Best2. We compared the electrophysiological responses of the olfactory epithelium to odorant stimulation, as well as the properties of Ca2+-activated Cl− currents in wild-type (WT) and knockout (KO) mice for Best2. Our results confirm that Best2 is expressed in the cilia of olfactory sensory neurons, while odorant responses and Ca2+-activated Cl− currents were not significantly different between WT and KO mice. Thus, Best2 does not appear to be the main molecular component of the olfactory channel. Further studies are required to determine the function of Best2 in the cilia of olfactory sensory neurons. PMID:19622610

  13. Visual responses in mice lacking critical components of all known retinal phototransduction cascades.

    PubMed

    Allen, Annette E; Cameron, Morven A; Brown, Timothy M; Vugler, Anthony A; Lucas, Robert J

    2010-11-29

    The mammalian visual system relies upon light detection by outer-retinal rod/cone photoreceptors and melanopsin-expressing retinal ganglion cells. Gnat1(-/-);Cnga3(-/-);Opn4(-/-) mice lack critical elements of each of these photoreceptive mechanisms via targeted disruption of genes encoding rod α transducin (Gnat1); the cone-specific α3 cyclic nucleotide gated channel subunit (Cnga3); and melanopsin (Opn4). Although assumed blind, we show here that these mice retain sufficiently widespread retinal photoreception to drive a reproducible flash electroretinogram (ERG). The threshold sensitivity of this ERG is similar to that of cone-based responses, however it is lost under light adapted conditions. Its spectral efficiency is consistent with that of rod opsin, but not cone opsins or melanopsin, indicating that it originates with light absorption by the rod pigment. The TKO light response survives intravitreal injection of U73122 (a phospholipase C antagonist), but is inhibited by a missense mutation of cone α transducin (Gnat2(cpfl3)), suggesting Gnat2-dependence. Visual responses in TKO mice extend beyond the retina to encompass the lateral margins of the lateral geniculate nucleus and components of the visual cortex. Our data thus suggest that a Gnat1-independent phototransduction mechanism downstream of rod opsin can support relatively widespread responses in the mammalian visual system. This anomalous rod opsin-based vision should be considered in experiments relying upon Gnat1 knockout to silence rod phototransduction.

  14. Mice lacking histone deacetylase 6 have hyperacetylated tubulin but are viable and develop normally.

    PubMed

    Zhang, Yu; Kwon, Sohee; Yamaguchi, Teppei; Cubizolles, Fabien; Rousseaux, Sophie; Kneissel, Michaela; Cao, Chun; Li, Na; Cheng, Hwei-Ling; Chua, Katrin; Lombard, David; Mizeracki, Adam; Matthias, Gabriele; Alt, Frederick W; Khochbin, Saadi; Matthias, Patrick

    2008-03-01

    Posttranslational modifications play important roles in regulating protein structure and function. Histone deacetylase 6 (HDAC6) is a mostly cytoplasmic class II HDAC, which has a unique structure with two catalytic domains and a domain binding ubiquitin with high affinity. This enzyme was recently identified as a multisubstrate protein deacetylase that can act on acetylated histone tails, alpha-tubulin and Hsp90. To investigate the in vivo functions of HDAC6 and the relevance of tubulin acetylation/deacetylation, we targeted the HDAC6 gene by homologous recombination in embryonic stem cells and generated knockout mice. HDAC6-deficient mice are viable and fertile and show hyperacetylated tubulin in most tissues. The highest level of expression of HDAC6 is seen in the testis, yet development and function of this organ are normal in the absence of HDAC6. Likewise, lymphoid development is normal, but the immune response is moderately affected. Furthermore, the lack of HDAC6 results in a small increase in cancellous bone mineral density, indicating that this deacetylase plays a minor role in bone biology. HDAC6-deficient mouse embryonic fibroblasts show apparently normal microtubule organization and stability and also show increased Hsp90 acetylation correlating with impaired Hsp90 function. Collectively, these data demonstrate that mice survive well without HDAC6 and that tubulin hyperacetylation is not detrimental to normal mammalian development.

  15. Insufficient glucose supply is linked to hypothermia upon cold exposure in high-fat diet-fed mice lacking PEMT.

    PubMed

    Gao, Xia; van der Veen, Jelske N; Fernandez-Patron, Carlos; Vance, Jean E; Vance, Dennis E; Jacobs, René L

    2015-09-01

    Mice that lack phosphatidylethanolamine N-methyltransferase (Pemt(-/-) mice) are protected from high-fat (HF) diet-induced obesity. HF-fed Pemt(-/-) mice show higher oxygen consumption and heat production, indicating that more energy might be utilized for thermogenesis and might account for the resistance to diet-induced weight gain. To test this hypothesis, HF-fed Pemt(-/-) and Pemt(+/+) mice were challenged with acute cold exposure at 4°C. Unexpectedly, HF-fed Pemt(-/-) mice developed hypothermia within 3 h of cold exposure. In contrast, chow-fed Pemt(-/-) mice, possessing similar body mass, maintained body temperature. Lack of PEMT did not impair the capacity for thermogenesis in skeletal muscle or brown adipose tissue. Plasma catecholamines were not altered by Pemt genotype, and stimulation of lipolysis was intact in brown and white adipose tissue of Pemt(-/-) mice. HF-fed Pemt(-/-) mice also developed higher systolic blood pressure, accompanied by reduced cardiac output. Choline supplementation reversed the cold-induced hypothermia in HF-fed Pemt(-/-) mice with no effect on blood pressure. Plasma glucose levels were ∼50% lower in HF-fed Pemt(-/-) mice compared with Pemt(+/+) mice. Choline supplementation normalized plasma hypoglycemia and the expression of proteins involved in gluconeogenesis. We propose that cold-induced hypothermia in HF-fed Pemt(-/-) mice is linked to plasma hypoglycemia due to compromised hepatic glucose production. Copyright © 2015 by the American Society for Biochemistry and Molecular Biology, Inc.

  16. Postsynaptic D2 dopamine receptor supersensitivity in the striatum of mice lacking TAAR1.

    PubMed

    Espinoza, Stefano; Ghisi, Valentina; Emanuele, Marco; Leo, Damiana; Sukhanov, Ilya; Sotnikova, Tatiana D; Chieregatti, Evelina; Gainetdinov, Raul R

    2015-06-01

    Trace Amine-Associated Receptor 1 (TAAR1) is a G protein-coupled receptor (GPCR) known to modulate dopaminergic system through several mechanisms. Mice lacking this receptor show a higher sensitivity to dopaminergic stimuli, such as amphetamine; however, it is not clear whether D1 or D2 dopamine receptors and which associated intracellular signaling events are involved in this modulation. In the striatum of TAAR1 knock out (TAAR1-KO mice) we found that D2, but not D1, dopamine receptors were over-expressed, both in terms of mRNA and protein levels. Moreover, the D2 dopamine receptor-related G protein-independent AKT/GSK3 signaling pathway was selectively activated, as indicated by the decrease of phosphorylation of AKT and GSK3β. The decrease in phospho-AKT levels, suggesting an increase in D2 dopamine receptor activity in basal conditions, was associated with an increase of AKT/PP2A complex, as revealed by co-immunoprecipitation experiments. Finally, we found that the locomotor activation induced by the D2 dopamine receptor agonist quinpirole, but not by the full D1 dopamine receptor agonist SKF-82958, was increased in TAAR1-KO mice. These data demonstrate pronounced supersensitivity of postsynaptic D2 dopamine receptors in the striatum of TAAR1-KO mice and indicate that a close interaction of TAAR1 and D2 dopamine receptors at the level of postsynaptic structures has important functional consequences. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Resistance to endotoxic shock in mice lacking natriuretic peptide receptor-A.

    PubMed

    Panayiotou, Catherine M; Baliga, Reshma; Stidwill, Raymond; Taylor, Valerie; Singer, Mervyn; Hobbs, Adrian J

    2010-08-01

    Excessive production of nitric oxide (NO) by inducible NO synthase (iNOS) is thought to underlie the vascular dysfunction, systemic hypotension and organ failure that characterize endotoxic shock. Plasma levels of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and C-type natriuretic peptide (CNP) are raised in animal models and humans with endotoxic shock and correlate with the associated cardiovascular dysfunction. Since both NO and natriuretic peptides play important roles in cardiovascular homeostasis via activation of guanylate cyclase-linked receptors, we used mice lacking natriuretic peptide receptor (NPR)-A (NPR1) to establish if natriuretic peptides contribute to the cardiovascular dysfunction present in endotoxic shock. Wild-type (WT) and NPR-A knockout (KO) mice were exposed to lipopolysaccharide (LPS) and vascular dysfunction (in vitro and in vivo), production of pro-inflammatory cytokines, and iNOS expression and activity were evaluated. LPS-treated WT animals exhibited a marked fall in mean arterial blood pressure (MABP) whereas NPR-A KO mice maintained MABP throughout. LPS administration caused a greater suppression of vascular responses to the thromboxane-mimetic U46619, ANP, acetylcholine and the NO-donor spermine-NONOate in WT versus NPR-A KO mice. This differential effect on vascular function was paralleled by reduced pro-inflammatory cytokine production, iNOS expression and activity (plasma [NO(x)] and cyclic GMP). These observations suggest that NPR-A activation by natriuretic peptides facilitates iNOS expression and contributes to the vascular dysfunction characteristic of endotoxic shock. Pharmacological interventions that target the natriuretic peptide system may represent a novel approach to treat this life-threatening condition.

  18. Analgesic tone conferred by constitutively active mu opioid receptors in mice lacking β-arrestin 2.

    PubMed

    Lam, Hoa; Maga, Matthew; Pradhan, Amynah; Evans, Christopher J; Maidment, Nigel T; Hales, Tim G; Walwyn, Wendy

    2011-04-12

    Hedonic reward, dependence and addiction are unwanted effects of opioid analgesics, linked to the phasic cycle of μ opioid receptor activation, tolerance and withdrawal. In vitro studies of recombinant G protein coupled receptors (GPCRs) over expressed in cell lines reveal an alternative tonic signaling mechanism that is independent of agonist. Such studies demonstrate that constitutive GPCR signaling can be inhibited by inverse agonists but not by neutral antagonists. However, ligand-independent activity has been difficult to examine in vivo, at the systems level, due to relatively low levels of constitutive activity of most GPCRs including μ receptors, often necessitating mutagenesis or pharmacological manipulation to enhance basal signaling. We previously demonstrated that the absence of β-arrestin 2 (β-arr2) augments the constitutive coupling of μ receptors to voltage-activated Ca²+ channels in primary afferent dorsal root ganglion neurons from β-arr2⁻/⁻ mice. We used this in vitro approach to characterize neutral competitive antagonists and inverse agonists of the constitutively active wild type μ receptors in neurons. We administered these agents to β-arr2⁻/⁻ mice to explore the role of constitutive μ receptor activity in nociception and hedonic tone. This study demonstrates that the induction of constitutive μ receptor activity in vivo in β-arr2⁻/⁻ mice prolongs tail withdrawal from noxious heat, a phenomenon that was reversed by inverse agonists, but not by antagonists that lack negative efficacy. By contrast, the aversive effects of inverse agonists were similar in β-arr2⁻/⁻ and β-arr2+/+ mice, suggesting that hedonic tone was unaffected.

  19. Analgesic tone conferred by constitutively active mu opioid receptors in mice lacking β-arrestin 2

    PubMed Central

    2011-01-01

    Hedonic reward, dependence and addiction are unwanted effects of opioid analgesics, linked to the phasic cycle of μ opioid receptor activation, tolerance and withdrawal. In vitro studies of recombinant G protein coupled receptors (GPCRs) over expressed in cell lines reveal an alternative tonic signaling mechanism that is independent of agonist. Such studies demonstrate that constitutive GPCR signaling can be inhibited by inverse agonists but not by neutral antagonists. However, ligand-independent activity has been difficult to examine in vivo, at the systems level, due to relatively low levels of constitutive activity of most GPCRs including μ receptors, often necessitating mutagenesis or pharmacological manipulation to enhance basal signaling. We previously demonstrated that the absence of β-arrestin 2 (β-arr2) augments the constitutive coupling of μ receptors to voltage-activated Ca2+ channels in primary afferent dorsal root ganglion neurons from β-arr2-/- mice. We used this in vitro approach to characterize neutral competitive antagonists and inverse agonists of the constitutively active wild type μ receptors in neurons. We administered these agents to β-arr2-/- mice to explore the role of constitutive μ receptor activity in nociception and hedonic tone. This study demonstrates that the induction of constitutive μ receptor activity in vivo in β-arr2-/- mice prolongs tail withdrawal from noxious heat, a phenomenon that was reversed by inverse agonists, but not by antagonists that lack negative efficacy. By contrast, the aversive effects of inverse agonists were similar in β-arr2-/- and β-arr2+/+ mice, suggesting that hedonic tone was unaffected. PMID:21486473

  20. Mice lacking α1,3-fucosyltransferase 9 exhibit modulation of in vivo immune responses against pathogens.

    PubMed

    Kashiwazaki, Hiromi; Kakizaki, Masatoshi; Ikehara, Yuzuru; Togayachi, Akira; Narimatsu, Hisashi; Watanabe, Rihito

    2014-05-01

    Carbohydrate structures, including Lewis X (Le(x)), which is not synthesized in mutant mice that lack α1,3-fucosyltransferase 9 (Fut9(-/-)), are involved in cell-cell recognition and inflammation. However, immunological alteration in Fut9(-/-) mice has not been studied. Thus, the inflammatory response of Fut9(-/-) mice was examined using the highly neurovirulent mouse hepatitis virus (MHV) JHMV srr7 strain. Pathological study revealed that inflammation induced in the brains of Fut9(-/-) mice after infection was more extensive compared with that of wild-type mice, although viral titers obtained from the brains of mutant mice were lower than those of wild-type mice. Furthermore, the reduction in cell numbers in the spleens of wild-type mice after infection was not observed in the infected Fut9(-/-) mice. Although there were no clear differences in the levels of cytokines examined in the brains between Fut9(-/-) and wild-type mice except for interferon-β expression, some of those in the spleens, including interferon-γ, interleukin-6, and monocyte chemoattractant protein 1, showed higher levels in Fut9(-/-) than in wild-type mice. Furthermore, Fut9(-/-) mice were refractory to the in vivo inoculation of endotoxin (LPS) compared with wild-type mice. These results indicate that Le(x) structures are involved in host responses against viral or bacterial challenges.

  1. A pro-nociceptive phenotype unmasked in mice lacking fatty-acid amide hydrolase

    PubMed Central

    Carey, Lawrence M; Slivicki, Richard A; Leishman, Emma; Cornett, Ben; Mackie, Ken; Bradshaw, Heather

    2016-01-01

    Fatty-acid amide hydrolase (FAAH) is the major enzyme responsible for degradation of anandamide, an endocannabinoid. Pharmacological inhibition or genetic deletion of FAAH (FAAH KO) produces antinociception in preclinical pain models that is largely attributed to anandamide-induced activation of cannabinoid receptors. However, FAAH metabolizes a wide range of structurally related, biologically active lipid signaling molecules whose functions remain largely unknown. Some of these endogenous lipids, including anandamide itself, may exert pro-nociceptive effects under certain conditions. In our study, FAAH KO mice exhibited a characteristic analgesic phenotype in the tail flick test and in both formalin and carrageenan models of inflammatory nociception. Nonetheless, intradermal injection of the transient receptor potential channel V1 (TRPV1) agonist capsaicin increased nocifensive behavior as well as mechanical and heat hypersensitivity in FAAH KO relative to wild-type mice. This pro-nociceptive phenotype was accompanied by increases in capsaicin-evoked Fos-like immunoreactive (FLI) cells in spinal dorsal horn regions implicated in nociceptive processing and was attenuated by CB1 (AM251) and TRPV1 (AMG9810) antagonists. When central sensitization was established, FAAH KO mice displayed elevated levels of anandamide, other fatty-acid amides, and endogenous TRPV1 agonists in both paw skin and lumbar spinal cord relative to wild-type mice. Capsaicin decreased spinal cord 2-AG levels and increased arachidonic acid and prostaglandin E2 levels in both spinal cord and paw skin irrespective of genotype. Our studies identify a previously unrecognized pro-nociceptive phenotype in FAAH KO mice that was unmasked by capsaicin challenge. The heightened nociceptive response was mediated by CB1 and TRPV1 receptors and accompanied by enhanced spinal neuronal activation. Moreover, genetic deletion of FAAH has a profound impact on the peripheral and central lipidome. Thus, genetic

  2. A pro-nociceptive phenotype unmasked in mice lacking fatty-acid amide hydrolase.

    PubMed

    Carey, Lawrence M; Slivicki, Richard A; Leishman, Emma; Cornett, Ben; Mackie, Ken; Bradshaw, Heather; Hohmann, Andrea G

    2016-01-01

    Fatty-acid amide hydrolase (FAAH) is the major enzyme responsible for degradation of anandamide, an endocannabinoid. Pharmacological inhibition or genetic deletion of FAAH (FAAH KO) produces antinociception in preclinical pain models that is largely attributed to anandamide-induced activation of cannabinoid receptors. However, FAAH metabolizes a wide range of structurally related, biologically active lipid signaling molecules whose functions remain largely unknown. Some of these endogenous lipids, including anandamide itself, may exert pro-nociceptive effects under certain conditions. In our study, FAAH KO mice exhibited a characteristic analgesic phenotype in the tail flick test and in both formalin and carrageenan models of inflammatory nociception. Nonetheless, intradermal injection of the transient receptor potential channel V1 (TRPV1) agonist capsaicin increased nocifensive behavior as well as mechanical and heat hypersensitivity in FAAH KO relative to wild-type mice. This pro-nociceptive phenotype was accompanied by increases in capsaicin-evoked Fos-like immunoreactive (FLI) cells in spinal dorsal horn regions implicated in nociceptive processing and was attenuated by CB1 (AM251) and TRPV1 (AMG9810) antagonists. When central sensitization was established, FAAH KO mice displayed elevated levels of anandamide, other fatty-acid amides, and endogenous TRPV1 agonists in both paw skin and lumbar spinal cord relative to wild-type mice. Capsaicin decreased spinal cord 2-AG levels and increased arachidonic acid and prostaglandin E2 levels in both spinal cord and paw skin irrespective of genotype. Our studies identify a previously unrecognized pro-nociceptive phenotype in FAAH KO mice that was unmasked by capsaicin challenge. The heightened nociceptive response was mediated by CB1 and TRPV1 receptors and accompanied by enhanced spinal neuronal activation. Moreover, genetic deletion of FAAH has a profound impact on the peripheral and central lipidome. Thus, genetic

  3. Spirulina platensis Lacks Antitumor Effect against Solid Ehrlich Carcinoma in Female Mice

    PubMed Central

    Barakat, Waleed; Elshazly, Shimaa M.; Mahmoud, Amr A. A.

    2015-01-01

    Spirulina is a blue-green alga used as a dietary supplement. It has been shown to possess anti-inflammatory, antioxidant, and hepatoprotective properties. This study was designed to evaluate the antitumor effect of spirulina (200 and 800 mg/kg) against a murine model of solid Ehrlich carcinoma compared to a standard chemotherapeutic drug, 5-fluorouracil (20 mg/kg). Untreated mice developed a palpable solid tumor after 13 days. Unlike fluorouracil, spirulina at the investigated two dose levels failed to exert any protective effect. In addition, spirulina did not potentiate the antitumor effect of fluorouracil when they were administered concurrently. Interestingly, their combined administration resulted in a dose-dependent increase in mortality. The present study demonstrates that spirulina lacks antitumor effect against this model of solid Ehrlich carcinoma and increased mortality when combined with fluorouracil. However, the implicated mechanism is still elusive. PMID:26366170

  4. Rapid Inflammation in Mice Lacking Both SOCS1 and SOCS3 in Hematopoietic Cells

    PubMed Central

    Ushiki, Takashi; Huntington, Nicholas D.; Glaser, Stefan P.; Kiu, Hiu; Georgiou, Angela; Zhang, Jian-Guo; Nicola, Nicos A.; Roberts, Andrew W.; Alexander, Warren S.

    2016-01-01

    The Suppressors of Cytokine Signalling (SOCS) proteins are negative regulators of cytokine signalling required to prevent excess cellular responses. SOCS1 and SOCS3 are essential to prevent inflammatory disease, SOCS1 by attenuating responses to IFNγ and gamma-common (γc) cytokines, and SOCS3 via regulation of G-CSF and IL-6 signalling. SOCS1 and SOCS3 show significant sequence homology and are the only SOCS proteins to possess a KIR domain. The possibility of overlapping or redundant functions was investigated in inflammatory disease via generation of mice lacking both SOCS1 and SOCS3 in hematopoietic cells. Loss of SOCS3 significantly accelerated the pathology and inflammatory disease characteristic of SOCS1 deficiency. We propose a model in which SOCS1 and SOCS3 operate independently to control specific cytokine responses and together modulate the proliferation and activation of lymphoid and myeloid cells to prevent rapid inflammatory disease. PMID:27583437

  5. Spirulina platensis Lacks Antitumor Effect against Solid Ehrlich Carcinoma in Female Mice.

    PubMed

    Barakat, Waleed; Elshazly, Shimaa M; Mahmoud, Amr A A

    2015-01-01

    Spirulina is a blue-green alga used as a dietary supplement. It has been shown to possess anti-inflammatory, antioxidant, and hepatoprotective properties. This study was designed to evaluate the antitumor effect of spirulina (200 and 800 mg/kg) against a murine model of solid Ehrlich carcinoma compared to a standard chemotherapeutic drug, 5-fluorouracil (20 mg/kg). Untreated mice developed a palpable solid tumor after 13 days. Unlike fluorouracil, spirulina at the investigated two dose levels failed to exert any protective effect. In addition, spirulina did not potentiate the antitumor effect of fluorouracil when they were administered concurrently. Interestingly, their combined administration resulted in a dose-dependent increase in mortality. The present study demonstrates that spirulina lacks antitumor effect against this model of solid Ehrlich carcinoma and increased mortality when combined with fluorouracil. However, the implicated mechanism is still elusive.

  6. Diminished Sonic hedgehog signaling and lack of floor plate differentiation in Gli2 mutant mice.

    PubMed

    Ding, Q; Motoyama, J; Gasca, S; Mo, R; Sasaki, H; Rossant, J; Hui, C C

    1998-07-01

    Floor plate cells at the midline of the neural tube are specified by high-level activity of Sonic hedgehog (Shh) secreted by notochord, whereas motor neurons are thought to be specified by a lower level activity of Shh secreted in turn by floor plate cells. In Drosophila, the Gli zinc finger protein Cubitus interruptus functions as a transcription factor activating Hedgehog-responsive genes. We report that the expression of known Shh-responsive genes such as Ptc and Gli1 is downregulated in mutant mice lacking Gli2 function. Gli2 mutants fail to develop a floor plate yet still develop motor neurons, which occupy the ventral midline of the neural tube. Our results imply that Gli2 is required to mediate high level but not low level Shh activity and show that the development of motor neurons can occur in the absence of floor plate induction.

  7. Hematopoietic Kit Deficiency, rather than Lack of Mast Cells, Protects Mice from Obesity and Insulin Resistance.

    PubMed

    Gutierrez, Dario A; Muralidhar, Sathya; Feyerabend, Thorsten B; Herzig, Stephan; Rodewald, Hans-Reimer

    2015-05-05

    Obesity, insulin resistance, and related pathologies are associated with immune-mediated chronic inflammation. Kit mutant mice are protected from diet-induced obesity and associated co-morbidities, and this phenotype has previously been attributed to their lack of mast cells. We performed a comprehensive metabolic analysis of Kit-dependent Kit(W/Wv) and Kit-independent Cpa3(Cre/+) mast-cell-deficient mouse strains, employing diet-induced or genetic (Lep(Ob/Ob) background) models of obesity. Our results show that mast cell deficiency, in the absence of Kit mutations, plays no role in the regulation of weight gain or insulin resistance. Moreover, we provide evidence that the metabolic phenotype observed in Kit mutant mice, while independent of mast cells, is immune regulated. Our data underscore the value of definitive mast cell deficiency models to conclusively test the involvement of this enigmatic cell in immune-mediated pathologies and identify Kit as a key hematopoietic factor in the pathogenesis of metabolic syndrome. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Mice lacking TR4 nuclear receptor develop mitochondrial myopathy with deficiency in complex I.

    PubMed

    Liu, Su; Lee, Yi-Fen; Chou, Samuel; Uno, Hideo; Li, Gonghui; Brookes, Paul; Massett, Michael P; Wu, Qiao; Chen, Lu-Min; Chang, Chawnshang

    2011-08-01

    The estimated incidence of mitochondrial diseases in humans is approximately 1:5000 to 1:10,000, whereas the molecular mechanisms for more than 50% of human mitochondrial disease cases still remain unclear. Here we report that mice lacking testicular nuclear receptor 4 (TR4(-/-)) suffered mitochondrial myopathy, and histological examination of TR4(-/-) soleus muscle revealed abnormal mitochondrial accumulation. In addition, increased serum lactate levels, decreased mitochondrial ATP production, and decreased electron transport chain complex I activity were found in TR4(-/-) mice. Restoration of TR4 into TR4(-/-) myoblasts rescued mitochondrial ATP generation capacity and complex I activity. Further real-time PCR quantification and promoter studies found TR4 could modulate complex I activity via transcriptionally regulating the complex I assembly factor NDUFAF1, and restoration of NDUFAF1 level in TR4(-/-) myoblasts increased mitochondrial ATP generation capacity and complex I activity. Together, these results suggest that TR4 plays vital roles in mitochondrial function, which may help us to better understand the pathogenesis of mitochondrial myopathy, and targeting TR4 via its ligands/activators may allow us to develop better therapeutic approaches.

  9. Lack of soluble fiber drives diet-induced adiposity in mice

    PubMed Central

    Chassaing, Benoit; Miles-Brown, Jennifer; Pellizzon, Michael; Ulman, Edward; Ricci, Matthew; Zhang, Limin; Patterson, Andrew D.; Vijay-Kumar, Matam

    2015-01-01

    Diet-induced obesity is often modeled by comparing mice fed high-fat diet (HFD), which is made from purified ingredients, vs. normal chow diet (NCD), which is a low-fat assemblage of relatively unrefined plant and animal products. The mechanism by which HFD promotes adiposity is complex but thought to involve low-grade inflammation and altered gut microbiota. The goal of this study was to investigate the extent to which HFD-induced adiposity is driven by fat content vs. other factors that differentiate HFD vs. NCD. Mice were fed NCD, HFD, or other compositionally defined diets (CDD), designed to mimic NCD and/or explore the role of HFD components. A range of metabolic parameters reflecting low-grade inflammation and adiposity were assayed. Relative to NCD, HFD, and to a lesser, but, nonetheless, significant extent, CDD induced increased adiposity, indicating both lipid content and other aspects of HFD are obesogenic. Moreover, HFD and CDD induced a rapid and marked loss of cecal and colonic mass. Such CDD-induced effects were not affected by adjusting dietary protein levels/types but could be largely eliminated by exchanging insoluble fiber (cellulose) for soluble fiber (inulin). Replacing cellulose with inulin in HFD also protected mice against decreased intestinal mass, hyperphagia, and increased adiposity. Such beneficial effects of inulin were microbiota dependent, correlated with elevated fecal short-chain fatty acid levels analyzed via 1H-NMR-based metabolomics and were partially recapitulated by administration of short-chain fatty acid. HFD-induced obesity is strongly promoted by its lack of soluble fiber, which supports microbiota-mediated intestinal tissue homeostasis that prevents inflammation driving obesity and metabolic syndrome. PMID:26185332

  10. Functional alterations to the nigrostriatal system in mice lacking all three members of the synuclein family

    PubMed Central

    Anwar, Sabina; Peters, Owen; Millership, Steven; Ninkina, Natalia; Doig, Natalie; Connor-Robson, Natalie; Threlfell, Sarah; Kooner, Gurdeep; Deacon, Robert M.; Bannerman, David M.; Bolam, J. Paul; Chandra, Sreeganga S.; Cragg, Stephanie J.; Wade-Martins, Richard; Buchman, Vladimir L.

    2011-01-01

    The synucleins (α, β and γ) are highly homologous proteins thought to play a role in regulating neurotransmission and are found abundantly in presynaptic terminals. To overcome functional overlap between synuclein proteins and to understand their role in presynaptic signalling from mesostriatal dopaminergic neurons, we produced mice lacking all three members of the synuclein family. The effect on the mesostriatal system was assessed in adult (4-14 month old) animals using a combination of behavioural, biochemical, histological and electrochemical techniques. Adult triple synuclein null (TKO) mice displayed no overt phenotype, and no change in the number of midbrain dopaminergic neurons. TKO mice were hyperactive in novel environments and exhibited elevated evoked release of dopamine in the striatum detected with fast-scan cyclic voltammetry. Elevated dopamine release was specific to the dorsal not ventral striatum and was accompanied by a decrease of dopamine tissue content. We confirmed a normal synaptic ultrastructure and a normal abundance of SNARE protein complexes in the dorsal striatum. Treatment of TKO animals with drugs affecting dopamine metabolism revealed normal rate of synthesis, enhanced turnover and reduced presynaptic striatal dopamine stores. Our data uniquely reveal the importance of the synuclein proteins in regulating neurotransmitter release from specific populations of midbrain dopamine neurons through mechanisms which differ from those reported in other neurons. The finding that the complete loss of synucleins leads to changes in dopamine handling by presynaptic terminals specifically in those regions preferentially vulnerable in Parkinson’s disease (PD) may ultimately inform on the selectivity of the disease process. PMID:21593311

  11. Contractile function is unaltered in diaphragm from mice lacking calcium release channel isoform 3

    NASA Technical Reports Server (NTRS)

    Clancy, J. S.; Takeshima, H.; Hamilton, S. L.; Reid, M. B.

    1999-01-01

    Skeletal muscle expresses at least two isoforms of the calcium release channel in the sarcoplasmic reticulum (RyR1 and RyR3). Whereas the function of RyR1 is well defined, the physiological significance of RyR3 is unclear. Some authors have suggested that RyR3 participates in excitation-contraction coupling and that RyR3 may specifically confer resistance to fatigue. To test this hypothesis, we measured contractile function of diaphragm strips from adult RyR3-deficient mice (exon 2-targeted mutation) and their heterozygous and wild-type littermates. In unfatigued diaphragm, there were no differences in isometric contractile properties (twitch characteristics, force-frequency relationships, maximal force) among the three groups. Our fatigue protocol (30 Hz, 0.25 duty cycle, 37 degrees C) depressed force to 25% of the initial force; however, lack of RyR3 did not accelerate the decline in force production. The force-frequency relationship was shifted to higher frequencies and was depressed in fatigued diaphragm; lack of RyR3 did not exaggerate these changes. We therefore provide evidence that RyR3 deficiency does not alter contractile function of adult muscle before, during, or after fatigue.

  12. Contractile function is unaltered in diaphragm from mice lacking calcium release channel isoform 3

    NASA Technical Reports Server (NTRS)

    Clancy, J. S.; Takeshima, H.; Hamilton, S. L.; Reid, M. B.

    1999-01-01

    Skeletal muscle expresses at least two isoforms of the calcium release channel in the sarcoplasmic reticulum (RyR1 and RyR3). Whereas the function of RyR1 is well defined, the physiological significance of RyR3 is unclear. Some authors have suggested that RyR3 participates in excitation-contraction coupling and that RyR3 may specifically confer resistance to fatigue. To test this hypothesis, we measured contractile function of diaphragm strips from adult RyR3-deficient mice (exon 2-targeted mutation) and their heterozygous and wild-type littermates. In unfatigued diaphragm, there were no differences in isometric contractile properties (twitch characteristics, force-frequency relationships, maximal force) among the three groups. Our fatigue protocol (30 Hz, 0.25 duty cycle, 37 degrees C) depressed force to 25% of the initial force; however, lack of RyR3 did not accelerate the decline in force production. The force-frequency relationship was shifted to higher frequencies and was depressed in fatigued diaphragm; lack of RyR3 did not exaggerate these changes. We therefore provide evidence that RyR3 deficiency does not alter contractile function of adult muscle before, during, or after fatigue.

  13. Lack of p47phox in Akita Diabetic Mice Is Associated with Interstitial Pneumonia, Fibrosis, and Oral Inflammation

    PubMed Central

    Zamakhchari, Mai F.; Sima, Corneliu; Sama, Kishore; Fine, Noah; Glogauer, Michael; Van Dyke, Thomas E.; Gyurko, Robert

    2017-01-01

    Excess reactive oxygen species production is central to the development of diabetic complications. The contribution of leukocyte reactive oxygen species produced by the NADPH oxidase to altered inflammatory responses associated with uncontrolled hyperglycemia is poorly understood. To get insight into the role of phagocytic superoxide in the onset of diabetic complications, we used a model of periodontitis in mice with chronic hyperglycemia and lack of leukocyte p47phox (Akita/Ncf1) bred from C57BL/6-Ins2Akita/J (Akita) and neutrophil cytosolic factor 1 knockout (Ncf1) mice. Akita/Nfc1 mice showed progressive cachexia starting at early age and increased mortality by six months. Their lungs developed infiltrative interstitial lesions that obliterated air spaces as early as 12 weeks when fungal colonization of lungs also was observed. Neutrophils of Akita/Ncf1 mice had normal degranulation and phagocytic efficiency when compared with wild-type mice. Although Akita/Ncf1 mice had increased prevalence of oral infections and more severe periodontitis compared with wild-type mice, bone loss was only marginally higher compared with Akita and Ncf1 null mice. Altogether these results indicate that lack of leukocyte superoxide production in mice with chronic hyperglycemia results in interstitial pneumonia and increased susceptibility to infections. PMID:26747235

  14. Intranasal delivery of naked DNA encoding the LACK antigen leads to protective immunity against visceral leishmaniasis in mice.

    PubMed

    Gomes, Daniel Cláudio de Oliveira; Pinto, Eduardo Fonseca; de Melo, Luiz Dione Barbosa; Lima, Wallace Pacienza; Larraga, Vicente; Lopes, Ulisses Gazos; Rossi-Bergmann, Bartira

    2007-03-08

    We previously showed that intranasal (i.n.) vaccination with pCIneo plasmid encoding the leishmanial LACK gene (pCIneo-LACK) induces long-lasting protective immunity against cutaneous leishmaniasis in mice. In this work, we proposed to investigate whether the efficacy of i.n. pCIneo-LACK is extensive to visceral leishmaniasis. BALB/c mice received two i.n. doses of 30 microg pCIneo-LACK prior to intravenous (i.v.) infection with Leishmania chagasi. Vaccinated mice developed significantly lower parasite burden in the liver and spleen than control mice receiving empty pCIneo or saline. The spleen cells of vaccinated mice produced significantly increased IFN-gamma and IL-4 concomitant with decreased IL-10 production during infection. Serum levels of specific IgG were elevated whereas TNF-alpha were decreased as compared with controls. These results show that the practical needle-free i.n. pCIneo-LACK vaccine displays potential broad-spectrum activity against leishmaniasis.

  15. Diabetes-induced hyperfiltration in adenosine A(1)-receptor deficient mice lacking the tubuloglomerular feedback mechanism.

    PubMed

    Sällström, J; Carlsson, P-O; Fredholm, B B; Larsson, E; Persson, A E G; Palm, F

    2007-07-01

    Glomerular hyperfiltration is commonly found in diabetic patients early after the onset of disease. This is one of the first indications of the development of progressive diabetic nephropathy. It has been proposed that glomerular hyperfiltration is caused by decreased delivery of electrolytes to the macula densa due to the increased sodium and glucose reabsorption in the proximal tubule, which would increase the glomerular filtration rate (GFR) via the tubuloglomerular feedback (TGF) mechanism. In this study, we investigated the role of TGF in diabetes-induced glomerular hyperfiltration by inducing diabetes in adenosine A(1)-receptor knockout (A1AR(-/-)) mice known to lack a functional TGF mechanism. Diabetes was induced by alloxan (75 mg kg(-1) bw) injected into the tail vein. The 24-hour urinary electrolyte excretion was measured in metabolic cages, the GFR determined by inulin clearance under isoflurane-anaesthesia, and histological changes evaluated. All alloxan-treated animals developed hyperglycaemia (> or =20 mm). Normoglycaemic animals had a similar GFR independent of genotype (A1AR(+/+) 9.3 +/- 0.5 vs. A1AR(-/-) 10.1 +/- 0.8 microL min(-1)g(-1) bw) and diabetes resulted in similar glomerular hyperfiltration in both groups (A1AR(+/+) 14.0 +/- 1.7, n = 9 vs. A1AR(-/-) 15.3 +/- 1.9 microL min(-1)g(-1) bw). Diabetic animals had a similar tendency to develop interstitial fibrosis, whereas the glomerular volume was similar in both genotypes, and unaltered by diabetes. This study shows that the A1AR(-/-) mice develop diabetes-induced glomerular hyperfiltration, demonstrating that the TGF mechanism is not the major cause of the development of hyperfiltration. Furthermore, the hyperfiltration in the present study was not related to alterations in the glomerular filtration area.

  16. Lack of Gαi2 leads to dilative cardiomyopathy and increased mortality in β1-adrenoceptor overexpressing mice

    PubMed Central

    Keller, Kirsten; Maass, Martina; Dizayee, Sara; Leiss, Veronika; Annala, Suvi; Köth, Jessica; Seemann, Wiebke K.; Müller-Ehmsen, Jochen; Mohr, Klaus; Nürnberg, Bernd; Engelhardt, Stefan; Herzig, Stefan; Birnbaumer, Lutz; Matthes, Jan

    2015-01-01

    Aims Inhibitory G (Gi) proteins have been proposed to be cardioprotective. We investigated effects of Gαi2 knockout on cardiac function and survival in a murine heart failure model of cardiac β1-adrenoceptor overexpression. Methods and results β1-transgenic mice lacking Gαi2 (β1-tg/Gαi2−/−) were compared with wild-type mice and littermates either overexpressing cardiac β1-adrenoceptors (β1-tg) or lacking Gαi2 (Gαi2−/−). At 300 days, mortality of mice only lacking Gαi2 was already higher compared with wild-type or β1-tg, but similar to β1-tg/Gαi2−/−, mice. Beyond 300 days, mortality of β1-tg/Gαi2−/− mice was enhanced compared with all other genotypes (mean survival time: 363 ± 21 days). At 300 days of age, echocardiography revealed similar cardiac function of wild-type, β1-tg, and Gαi2−/− mice, but significant impairment for β1-tg/Gαi2−/− mice (e.g. ejection fraction 14 ± 2 vs. 40 ± 4% in wild-type mice). Significantly increased ventricle-to-body weight ratio (0.71 ± 0.06 vs. 0.48 ± 0.02% in wild-type mice), left ventricular size (length 0.82 ± 0.04 vs. 0.66 ± 0.03 cm in wild types), and atrial natriuretic peptide and brain natriuretic peptide expression (mRNA: 2819 and 495% of wild-type mice, respectively) indicated hypertrophy. Gαi3 was significantly up-regulated in Gαi2 knockout mice (protein compared with wild type: 340 ± 90% in Gαi2−/− and 394 ± 80% in β1-tg/Gαi2−/−, respectively). Conclusions Gαi2 deficiency combined with cardiac β1-adrenoceptor overexpression strongly impaired survival and cardiac function. At 300 days of age, β1-adrenoceptor overexpression alone had not induced cardiac hypertrophy or dysfunction while there was overt cardiomyopathy in mice additionally lacking Gαi2. We propose an enhanced effect of increased β1-adrenergic drive by the lack of protection via Gαi2. Gαi3 up-regulation was not sufficient to compensate for Gαi2 deficiency, suggesting an isoform-specific or

  17. Loss of cocaine locomotor response in Pitx3-deficient mice lacking a nigrostriatal pathway.

    PubMed

    Beeler, Jeff A; Cao, Zhen Fang Huang; Kheirbek, Mazen A; Zhuang, Xiaoxi

    2009-04-01

    Both the dorsal and ventral striatum have been demonstrated to have a critical role in reinforcement learning and addiction. Dissecting the specific function of these striatal compartments and their associated nigrostriatal and mesoaccumbens dopamine pathways, however, has proved difficult. Previous studies using lesions to isolate the contribution of nigrostriatal and mesoaccumbens dopamine in mediating the locomotor and reinforcing effects of psychostimulant drugs have yielded inconsistent and inconclusive results. Using a naturally occurring mutant mouse line, aphakia, that lacks a nigrostriatal dopamine pathway but retains an intact mesoaccumbens pathway, we show that the locomotor activating effects of cocaine, including locomotor sensitization, are dependent on an intact nigrostriatal dopamine projection. In contrast, cocaine reinforcement, as measured by conditioned place preference and cocaine sensitization of sucrose preference, is intact in these mice. In light of the well-established role of the nucleus accumbens in mediating the effects of psychostimulants, these data suggest that the nigrostriatal pathway can act as a critical effector mechanism for the nucleus accumbens highlighting the importance of intrastriatal connectivity and providing insight into the functional architecture of the striatum.

  18. Pituitary Phenotypes of Mice Lacking the Notch Signalling Ligand Delta-Like 1 Homologue

    PubMed Central

    Cheung, L Y M; Rizzoti, K; Lovell-Badge, R; Tissier, P R

    2013-01-01

    The Notch signalling pathway ligand delta-like 1 homologue (Dlk1, also named Pref1) is expressed throughout the developing pituitary and becomes restricted to mostly growth hormone (GH) cells within the adult gland. We have investigated the role of Dlk1 in pituitary development and function from late embryogenesis to adulthood using a mouse model completely lacking the expression of Dlk1. We confirm that Dlk1-null mice are shorter and weigh less than wild-type littermates from late gestation, at parturition and in adulthood. A loss of Dlk1 leads to significant reduction in GH content throughout life, whereas other pituitary hormones are reduced to varying degrees depending on sex and age. Both the size of the pituitary and the proportion of hormone-producing cell populations are unchanged, suggesting that there is a reduction in hormone content per cell. In vivo challenge of mutant and wild-type littermates with growth hormone-releasing hormone and growth hormone-releasing hexapeptide shows that reduced GH secretion is unlikely to account for the reduced growth of Dlk1 knockout animals. These data suggest that loss of Dlk1 gives rise to minor pituitary defects manifesting as an age- and sex-dependent reduction in pituitary hormone contents. However, Dlk1 expression in other tissue is most likely responsible for the weight and length differences observed in mutant animals. PMID:23279263

  19. Onset coding is degraded in auditory nerve fibers from mutant mice lacking synaptic ribbons.

    PubMed

    Buran, Bradley N; Strenzke, Nicola; Neef, Andreas; Gundelfinger, Eckart D; Moser, Tobias; Liberman, M Charles

    2010-06-02

    Synaptic ribbons, found at the presynaptic membrane of sensory cells in both ear and eye, have been implicated in the vesicle-pool dynamics of synaptic transmission. To elucidate ribbon function, we characterized the response properties of single auditory nerve fibers in mice lacking Bassoon, a scaffolding protein involved in anchoring ribbons to the membrane. In bassoon mutants, immunohistochemistry showed that fewer than 3% of the hair cells' afferent synapses retained anchored ribbons. Auditory nerve fibers from mutants had normal threshold, dynamic range, and postonset adaptation in response to tone bursts, and they were able to phase lock with normal precision to amplitude-modulated tones. However, spontaneous and sound-evoked discharge rates were reduced, and the reliability of spikes, particularly at stimulus onset, was significantly degraded as shown by an increased variance of first-spike latencies. Modeling based on in vitro studies of normal and mutant hair cells links these findings to reduced release rates at the synapse. The degradation of response reliability in these mutants suggests that the ribbon and/or Bassoon normally facilitate high rates of exocytosis and that its absence significantly compromises the temporal resolving power of the auditory system.

  20. Mitochondrial Lipid Abnormality and Electron Transport Chain Impairment in Mice Lacking α-Synuclein†

    PubMed Central

    Ellis, Christopher E.; Murphy, Eric J.; Mitchell, Drake C.; Golovko, Mikhail Y.; Scaglia, Fernando; Barceló-Coblijn, Gwendolyn C.; Nussbaum, Robert L.

    2005-01-01

    The presynaptic protein α-synuclein, implicated in Parkinson disease (PD), binds phospholipids and has a role in brain fatty acid (FA) metabolism. In mice lacking α-synuclein (Snca−/−), total brain steady-state mass of the mitochondria-specific phospholipid, cardiolipin, is reduced 22% and its acyl side chains show a 51% increase in saturated FAs and a 25% reduction in essential n-6, but not n-3, polyunsaturated FAs. Additionally, 23% reduction in phosphatidylglycerol content, the immediate biosynthetic precursor of cardiolipin, was observed without alterations in the content of other brain phospholipids. Consistent with these changes, more ordered lipid head group and acyl chain packing with enhanced rotational motion of diphenylhexatriene (DPH) about its long axis were demonstrated in time-resolved DPH fluorescence lifetime experiments. These abnormalities in mitochondrial membrane properties were associated with a 15% reduction in linked complex I/III activity of the electron transport chain, without reductions in mitochondrial number, complex II/III activity, or individual complex I, II, III, or IV activity. Reduced complex I activity is thought to be a critical factor in the development of PD. Thus, altered membrane composition and structure and impaired complex I/III function in Snca−/− brain suggest a relationship between α-synuclein's role in brain lipid metabolism, mitochondrial function, and PD. PMID:16260631

  1. Mice lacking GD3 synthase display morphological abnormalities in the sciatic nerve and neuronal disturbances during peripheral nerve regeneration.

    PubMed

    Ribeiro-Resende, Victor Túlio; Araújo Gomes, Tiago; de Lima, Silmara; Nascimento-Lima, Maiara; Bargas-Rega, Michele; Santiago, Marcelo Felipe; Reis, Ricardo Augusto de Melo; de Mello, Fernando Garcia

    2014-01-01

    The ganglioside 9-O-acetyl GD3 is overexpressed in peripheral nerves after lesioning, and its expression is correlated with axonal degeneration and regeneration in adult rodents. However, the biological roles of this ganglioside during the regenerative process are unclear. We used mice lacking GD3 synthase (Siat3a KO), an enzyme that converts GM3 to GD3, which can be further converted to 9-O-acetyl GD3. Morphological analyses of longitudinal and transverse sections of the sciatic nerve revealed significant differences in the transverse area and nerve thickness. The number of axons and the levels of myelin basic protein were significantly reduced in adult KO mice compared to wild-type (WT) mice. The G-ratio was increased in KO mice compared to WT mice based on quantification of thin transverse sections stained with toluidine blue. We found that neurite outgrowth was significantly reduced in the absence of GD3. However, addition of exogenous GD3 led to neurite growth after 3 days, similar to that in WT mice. To evaluate fiber regeneration after nerve lesioning, we compared the regenerated distance from the lesion site and found that this distance was one-fourth the length in KO mice compared to WT mice. KO mice in which GD3 was administered showed markedly improved regeneration compared to the control KO mice. In summary, we suggest that 9-O-acetyl GD3 plays biological roles in neuron-glia interactions, facilitating axonal growth and myelination induced by Schwann cells. Moreover, exogenous GD3 can be converted to 9-O-acetyl GD3 in mice lacking GD3 synthase, improving regeneration.

  2. Mice Lacking GD3 Synthase Display Morphological Abnormalities in the Sciatic Nerve and Neuronal Disturbances during Peripheral Nerve Regeneration

    PubMed Central

    Ribeiro-Resende, Victor Túlio; Gomes, Tiago Araújo; de Lima, Silmara; Nascimento-Lima, Maiara; Bargas-Rega, Michele; Santiago, Marcelo Felipe; Reis, Ricardo Augusto de Melo; de Mello, Fernando Garcia

    2014-01-01

    The ganglioside 9-O-acetyl GD3 is overexpressed in peripheral nerves after lesioning, and its expression is correlated with axonal degeneration and regeneration in adult rodents. However, the biological roles of this ganglioside during the regenerative process are unclear. We used mice lacking GD3 synthase (Siat3a KO), an enzyme that converts GM3 to GD3, which can be further converted to 9-O-acetyl GD3. Morphological analyses of longitudinal and transverse sections of the sciatic nerve revealed significant differences in the transverse area and nerve thickness. The number of axons and the levels of myelin basic protein were significantly reduced in adult KO mice compared to wild-type (WT) mice. The G-ratio was increased in KO mice compared to WT mice based on quantification of thin transverse sections stained with toluidine blue. We found that neurite outgrowth was significantly reduced in the absence of GD3. However, addition of exogenous GD3 led to neurite growth after 3 days, similar to that in WT mice. To evaluate fiber regeneration after nerve lesioning, we compared the regenerated distance from the lesion site and found that this distance was one-fourth the length in KO mice compared to WT mice. KO mice in which GD3 was administered showed markedly improved regeneration compared to the control KO mice. In summary, we suggest that 9-O-acetyl GD3 plays biological roles in neuron-glia interactions, facilitating axonal growth and myelination induced by Schwann cells. Moreover, exogenous GD3 can be converted to 9-O-acetyl GD3 in mice lacking GD3 synthase, improving regeneration. PMID:25330147

  3. Lack of stress responses to long-term effects of corticosterone in Caps2 knockout mice.

    PubMed

    Mishima, Yuriko; Shinoda, Yo; Sadakata, Tetsushi; Kojima, Masami; Wakana, Shigeharu; Furuichi, Teiichi

    2015-03-10

    Chronic stress is associated with anxiety and depressive disorders, and can cause weight gain. Ca(2+)-dependent activator protein for secretion 2 (CAPS2) is involved in insulin release. Caps2 knockout (KO) mice exhibit decreased body weight, reduced glucose-induced insulin release, and abnormal psychiatric behaviors. We chronically administered the stress hormone corticosterone (CORT), which induces anxiety/depressive-like behavior and normally increases plasma insulin levels, via the drinking water for 10 weeks, and we examined the stress response in KO mice. Chronic CORT exposure inhibited stress-induced serum CORT elevation in wild-type (WT) mice, but not in KO mice. Poor weight gain in CORT-treated animals was observed until week 6 in WT mice, but persisted for the entire duration of the experiment in KO mice, although there is no difference in drug*genotype interaction. Among KO mice, food consumption was unchanged, while water consumption was higher, over the duration of the experiment in CORT-treated animals, compared with untreated animals. Moreover, serum insulin and leptin levels were increased in CORT-treated WT mice, but not in KO mice. Lastly, both WT and KO mice displayed anxiety/depressive-like behavior after CORT administration. These results suggest that Caps2 KO mice have altered endocrine responses to CORT administration, while maintaining CORT-induced anxiety/depressive-like behavior.

  4. Styrene Trimer May Increase Thyroid Hormone Levels via Down-Regulation of the Aryl Hydrocarbon Receptor (AhR) Target Gene UDP-Glucuronosyltransferase

    PubMed Central

    Yanagiba, Yukie; Ito, Yuki; Yamanoshita, Osamu; Zhang, Shu-Yun; Watanabe, Gen; Taya, Kazuyoshi; Li, Chun Mei; Inotsume, Yuko; Kamijima, Michihiro; Gonzalez, Frank J.; Nakajima, Tamie

    2008-01-01

    Background Styrene trimers (STs) are polystyrene-container–eluted materials that are sometimes detected in packaged foods. Although the possible endocrine-disrupting effects of STs, such as estrogenic activities, have been reported, their potential thyroid toxicity, such as that caused by the related endocrine disruptor 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), has not been studied in detail. Objective Using wild-type and aryl hydrocarbon receptor (Ahr)–null mice, we investigated whether 2,4,6-triphenyl-1-hexene (ST-1), an isomer of STs, influences thyroxin (T4) levels in the same manner as TCDD, which induces UDP-glucuronosyltransferase (UGT) via the AhR, resulting in a decrease in T4 levels in the plasma of mice. Methods Both wild-type and Ahr-null mice (five mice per group) were treated for 4 days by gavage with ST-1 (0, 32, or 64 μmol/kg). Results High-dose (64 μmol/kg) ST-1 decreased the expression of AhR, cytochrome P450 (CYP) 1A1/2, UGT1A1/A6, and CYP2B10 mRNAs and the enzyme activity for CYP1A and UGT1A only in the wild-type mice. This dose decreased AhR DNA binding, but paradoxically increased AhR translocation to the nucleus. In contrast, a high dose of ST-1 increased T4 levels in the plasma in wild-type mice but did not influence T4 levels in AhR-null mice. Conclusions Although ST-1 treatment might cause an increase in AhR levels in the nucleus by inhibiting AhR export, this chemical down-regulated AhR mRNA, thus leading to down-regulation of AhR target genes and an increase in plasma T4 levels. PMID:18560529

  5. Early Signs of Pathological Cognitive Aging in Mice Lacking High-Affinity Nicotinic Receptors.

    PubMed

    Konsolaki, Eleni; Tsakanikas, Panagiotis; Polissidis, Alexia V; Stamatakis, Antonios; Skaliora, Irini

    2016-01-01

    In order to address pathological cognitive decline effectively, it is critical to adopt early preventive measures in individuals considered at risk. It is therefore essential to develop approaches that identify such individuals before the onset of irreversible dementia. A deficient cholinergic system has been consistently implicated as one of the main factors associated with a heightened vulnerability to the aging process. In the present study we used mice lacking high affinity nicotinic receptors (β2-/-), which have been proposed as an animal model of accelerated/premature cognitive aging. Our aim was to identify behavioral signs that could serve as indicators or predictors of impending cognitive decline. We used test batteries in order to assess cognitive functions and additional tasks to investigate spontaneous behaviors, such as species-specific activities and exploration/locomotion in a novel environment. Our data confirm the hypothesis that β2-/- animals exhibit age-related cognitive impairments in spatial learning. In addition, they document age-related deficits in other areas, such as recognition memory, burrowing and nesting building, thereby extending the validity of this animal model for the study of pathological aging. Finally, our data reveal deficits in spontaneous behavior and habituation processes that precede the onset of cognitive decline and could therefore be useful as a non-invasive behavioral screen for identifying animals at risk. To our knowledge, this is the first study to perform an extensive behavioral assessment of an animal model of premature cognitive aging, and our results suggest that β2-nAChR dependent cognitive deterioration progressively evolves from initial subtle behavioral changes to global dementia due to the combined effect of the neuropathology and aging.

  6. Early Signs of Pathological Cognitive Aging in Mice Lacking High-Affinity Nicotinic Receptors

    PubMed Central

    Konsolaki, Eleni; Tsakanikas, Panagiotis; Polissidis, Alexia V.; Stamatakis, Antonios; Skaliora, Irini

    2016-01-01

    In order to address pathological cognitive decline effectively, it is critical to adopt early preventive measures in individuals considered at risk. It is therefore essential to develop approaches that identify such individuals before the onset of irreversible dementia. A deficient cholinergic system has been consistently implicated as one of the main factors associated with a heightened vulnerability to the aging process. In the present study we used mice lacking high affinity nicotinic receptors (β2-/-), which have been proposed as an animal model of accelerated/premature cognitive aging. Our aim was to identify behavioral signs that could serve as indicators or predictors of impending cognitive decline. We used test batteries in order to assess cognitive functions and additional tasks to investigate spontaneous behaviors, such as species-specific activities and exploration/locomotion in a novel environment. Our data confirm the hypothesis that β2-/- animals exhibit age-related cognitive impairments in spatial learning. In addition, they document age-related deficits in other areas, such as recognition memory, burrowing and nesting building, thereby extending the validity of this animal model for the study of pathological aging. Finally, our data reveal deficits in spontaneous behavior and habituation processes that precede the onset of cognitive decline and could therefore be useful as a non-invasive behavioral screen for identifying animals at risk. To our knowledge, this is the first study to perform an extensive behavioral assessment of an animal model of premature cognitive aging, and our results suggest that β2-nAChR dependent cognitive deterioration progressively evolves from initial subtle behavioral changes to global dementia due to the combined effect of the neuropathology and aging. PMID:27199738

  7. Delayed pubertal onset and prepubertal Kiss1 expression in female mice lacking central oestrogen receptor beta.

    PubMed

    Naulé, Lydie; Robert, Vincent; Parmentier, Caroline; Martini, Mariangela; Keller, Matthieu; Cohen-Solal, Martine; Hardin-Pouzet, Hélène; Grange-Messent, Valérie; Franceschini, Isabelle; Mhaouty-Kodja, Sakina

    2015-12-20

    Ovarian oestradiol is essential for pubertal maturation and adult physiology of the female reproductive axis. It acts at central and peripheral sites through two main oestrogen receptors (ER) α and β. Here we investigate the role of ERβ on central effects of oestradiol, by generating a mouse line specifically lacking the ERβ gene in neuronal and glial cells. Central ERβ deletion delays the age at vaginal opening and first oestrous and reduces uterine weight without affecting body growth. Analysis of factors necessary for pubertal progression shows reduced levels of Kiss1 transcripts at postnatal (P) day 25 in the preoptic area, but not in the mediobasal hypothalamus (MBH) of mutant females. In agreement with these data, the number of kisspeptin-immunoreactive neurons was decreased by 57-72% in the three subdivisions of the rostral periventricular area of the third ventricle (RP3V), whereas the density of kisspeptin-immunoreactive fibres was unchanged in the arcuate nucleus of mutant mice. These alterations do not involve changes in ERα mRNAs in the preoptic area and protein levels in the RP3V. The number and distribution of GnRH-immunoreactive cells were unaffected, but gonadotropin-releasing hormone (GnRH) transcript levels were higher in the P25 preoptic area of mutants. At adulthood, mutant females have normal oestrous cyclicity, kisspeptin system and exhibit unaltered sexual behaviour. They display, however, reduced ovary weight and increased anxiety-related behaviour during the follicular phase. This argues for the specific involvement of central ERβ in the regulation of pubertal onset in female reproduction, possibly through prepubertal induction of kisspeptin expression in the RP3V.

  8. AhR modulates the IL-22-producing cell proliferation/recruitment in imiquimod-induced psoriasis mouse model.

    PubMed

    Cochez, Perrine M; Michiels, Camille; Hendrickx, Emilie; Van Belle, Astrid B; Lemaire, Muriel M; Dauguet, Nicolas; Warnier, Guy; de Heusch, Magali; Togbe, Dieudonnée; Ryffel, Bernhard; Coulie, Pierre G; Renauld, Jean-Christophe; Dumoutier, Laure

    2016-06-01

    IL-22 has a detrimental role in skin inflammatory processes, for example in psoriasis. As transcription factor, AhR controls the IL-22 production by several cell types (i.e. Th17 cells). Here, we analyzed the role of Ahr in IL-22 production by immune cells in the inflamed skin, using an imiquimod-induced psoriasis mouse model. Our results indicate that IL-22 is expressed in the ear of imiquimod-treated Ahr(-/-) mice but less than in wild-type mice. We then studied the role of AhR on three cell populations known to produce IL-22 in the skin: γδ T cells, Th17 cells, and ILC3, and a novel IL-22-producing cell type identified in this setting: CD4(-) CD8(-) TCRβ(+) T cells. We showed that AhR is required for IL-22 production by Th17, but not by the three other cell types, in the imiquimod-treated ears. Moreover, AhR has a role in the recruitment of γδ T cells, ILC3, and CD4(-) CD8(-) TCRβ(+) T cells into the inflamed skin or in their local proliferation. Taken together, AhR has a direct role in IL-22 production by Th17 cells in the mouse ear skin, but not by γδ T cells, CD4(-) CD8(-) TCRβ(+) T cells and ILCs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Caffeine reverses antinociception by amitriptyline in wild type mice but not in those lacking adenosine A1 receptors.

    PubMed

    Sawynok, Jana; Reid, Allison R; Fredholm, Bertil B

    2008-08-01

    Amitriptyline is used to treat neuropathic pain in humans. It produces antinociception in several animal models of pain, and this effect is blocked by methylxanthine adenosine receptor antagonists which implicates adenosine it its actions. Here, the antinociceptive effect of amitriptyline, and the ability of caffeine to reverse it, were examined using the formalin test (a model of persistent pain) in wild type mice and mice lacking the adenosine A(1) receptor (A1R). Amitriptyline produced dose-related suppression of flinching in wild type mice following both systemic and intraplantar drug administration; both of these effects were unaltered in A1R -/- mice. Following systemic administration, caffeine reversed the systemic effect of amitriptyline in wild type, but not A1R -/- mice; -/+ mice exhibited an intermediate effect. Intraplantar administration of caffeine also reversed the effect of intraplantar amitriptyline in A1R +/+, but not in -/- or +/- mice. These results indicate that adenosine A(1) receptors are not required in order for amitriptyline to cause antinociception in mice, but they are required to see caffeine reversal of this antinociceptive effect. When A1Rs are present, actions of amitriptyline may, however, partly depend on A1Rs.

  10. A lack of functional NK1 receptors explains most, but not all, abnormal behaviours of NK1R-/- mice1

    PubMed Central

    Porter, A J; Pillidge, K; Tsai, Y C; Dudley, J A; Hunt, S P; Peirson, S N; Brown, L A; Stanford, S C

    2015-01-01

    Mice lacking functional neurokinin-1 receptors (NK1R-/-) display abnormal behaviours seen in Attention Deficit Hyperactivity Disorder (hyperactivity, impulsivity and inattentiveness). These abnormalities were evident when comparing the behaviour of separate (inbred: ‘Hom’) wildtype and NK1R-/- mouse strains. Here, we investigated whether the inbreeding protocol could influence their phenotype by comparing the behaviour of these mice with that of wildtype (NK1R+/+) and NK1R-/- progeny of heterozygous parents (‘Het’, derived from the same inbred strains). First, we recorded the spontaneous motor activity of the two colonies/genotypes, over 7 days. This continuous monitoring also enabled us to investigate whether the diurnal rhythm in motor activity differs in the two colonies/genotypes. NK1R-/- mice from both colonies were hyperactive compared with their wildtypes and their diurnal rhythm was also disrupted. Next, we evaluated the performance of the four groups of mice in the 5-Choice Serial Reaction-Time Task (5-CSRTT). During training, NK1R-/- mice from both colonies expressed more impulsive and perseverative behaviour than their wildtypes. During testing, only NK1R-/- mice from the Hom colony were more impulsive than their wildtypes, but NK1R-/- mice from both colonies were more perseverative. There were no colony differences in inattentiveness. Moreover, a genotype difference in this measure depended on time of day. We conclude that the hyperactivity, perseveration and, possibly, inattentiveness of NK1R-/- mice is a direct consequence of a lack of functional NK1R. However, the greater impulsivity of NK1R-/- mice depended on an interaction between a functional deficit of NK1R and other (possibly environmental and/or epigenetic) factors. PMID:25558794

  11. Expansion of the lateral ventricles and ependymal deficits underlie the hydrocephalus evident in mice lacking the transcription factor NFIX.

    PubMed

    Vidovic, Diana; Harris, Lachlan; Harvey, Tracey J; Evelyn Heng, Yee Hsieh; Smith, Aaron G; Osinski, Jason; Hughes, James; Thomas, Paul; Gronostajski, Richard M; Bailey, Timothy L; Piper, Michael

    2015-08-07

    Nuclear factor one X (NFIX) has been shown to play a pivotal role during the development of many regions of the brain, including the neocortex, the hippocampus and the cerebellum. Mechanistically, NFIX has been shown to promote neural stem cell differentiation through the activation of astrocyte-specific genes and via the repression of genes central to progenitor cell self-renewal. Interestingly, mice lacking Nfix also exhibit other phenotypes with respect to development of the central nervous system, and whose underlying causes have yet to be determined. Here we examine one of the phenotypes displayed by Nfix(-/-) mice, namely hydrocephalus. Through the examination of embryonic and postnatal Nfix(-/-) mice we reveal that hydrocephalus is first seen at around postnatal day (P) 10 in mice lacking Nfix, and is fully penetrant by P20. Furthermore, we examined the subcommissural organ (SCO), the Sylvian aqueduct and the ependymal layer of the lateral ventricles, regions that when malformed and functionally perturbed have previously been implicated in the development of hydrocephalus. SOX3 is a factor known to regulate SCO development. Although we revealed that NFIX could repress Sox3-promoter-driven transcriptional activity in vitro, SOX3 expression within the SCO was normal within Nfix(-/-) mice, and Nfix mutant mice showed no abnormalities in the structure or function of the SCO. Moreover, these mutant mice exhibited no overt blockage of the Sylvian aqueduct. However, the ependymal layer of the lateral ventricles was frequently absent in Nfix(-/-) mice, suggesting that this phenotype may underlie the development of hydrocephalus within these knockout mice.

  12. Abnormal anxiety- and depression-like behaviors in mice lacking both central serotonergic neurons and pancreatic islet cells

    PubMed Central

    Jia, Yun-Fang; Song, Ning-Ning; Mao, Rong-Rong; Li, Jin-Nan; Zhang, Qiong; Huang, Ying; Zhang, Lei; Han, Hui-Li; Ding, Yu-Qiang; Xu, Lin

    2014-01-01

    Dysfunction of central serotonin (5-HT) system has been proposed to be one of the underlying mechanisms for anxiety and depression, and the association of diabetes mellitus and psychiatric disorders has been noticed by the high prevalence of anxiety/depression in patients with diabetes mellitus. This promoted us to examine these behaviors in central 5-HT-deficient mice and those also suffering with diabetes mellitus. Mice lacking either 5-HT or central serotonergic neurons were generated by conditional deletion of Tph2 or Lmx1b respectively. Simultaneous depletion of both central serotonergic neurons and pancreatic islet cells was achieved by administration of diphtheria toxin (DT) in Pet1-Cre;Rosa26-DT receptor (DTR) mice. The central 5-HT-deficient mice showed reduced anxiety-like behaviors as they spent more time in and entered more often into the light box in the light/dark box test compared with controls; similar results were observed in the elevated plus maze test. However, they displayed no differences in the immobility time of the forced swimming and tail suspension tests suggesting normal depression-like behaviors in central 5-HT-deficient mice. As expected, DT-treated Pet1-Cre;Rosa26-DTR mice lacking both central serotonergic neurons and pancreatic islet endocrine cells exhibited several classic diabetic symptoms. Interestingly, they displayed increased anxiety-like behaviors but reduced immobility time in the forced swimming and tail suspension tests. Furthermore, the hippocampal neurogenesis was dramatically enhanced in these mice. These results suggest that the deficiency of central 5-HT may not be sufficient to induce anxiety/depression-like behaviors in mice, and the enhanced hippocampal neurogenesis may contribute to the altered depression-like behaviors in the 5-HT-deficient mice with diabetes. Our current investigation provides understanding the relationship between diabetes mellitus and psychiatric disorders. PMID:25294992

  13. TERATOGENIC RESPONSES ARE MODULATED IN MICE LACKING EXPRESSION OF EPIDERMAL GROWTH FACTOR (EGF) AND TRANSFORMING GROWTH FACTOR-ALPHA (TGF)

    EPA Science Inventory

    TITLE:
    TERATOGENIC RESPONSES ARE MODULATED IN MICE LACKING EXPRESSION OF EPIDERMAL GROWTH FACTOR (EGF) AND TRANSFORMING GROWTH FACTOR-ALPHA (TGF). AUTHORS (ALL): Abbott, Barbara D.1; Best, Deborah S.1; Narotsky, Michael G.1. SPONSOR NAME: None INSTITUTIONS (ALL): 1. Repro Tox ...

  14. TERATOGENIC RESPONSES ARE MODULATED IN MICE LACKING EXPRESSION OF EPIDERMAL GROWTH FACTOR (EGF) AND TRANSFORMING GROWTH FACTOR-ALPHA (TGF)

    EPA Science Inventory

    TITLE:
    TERATOGENIC RESPONSES ARE MODULATED IN MICE LACKING EXPRESSION OF EPIDERMAL GROWTH FACTOR (EGF) AND TRANSFORMING GROWTH FACTOR-ALPHA (TGF). AUTHORS (ALL): Abbott, Barbara D.1; Best, Deborah S.1; Narotsky, Michael G.1. SPONSOR NAME: None INSTITUTIONS (ALL): 1. Repro Tox ...

  15. Characterization of metabolic phenotypes of mice lacking GPR61, an orphan G-protein coupled receptor.

    PubMed

    Nambu, Hirohide; Fukushima, Miyuki; Hikichi, Hirohiko; Inoue, Takao; Nagano, Norihiro; Tahara, Yoshio; Nambu, Tadahiro; Ito, Junko; Ogawa, Yoshihiro; Ozaki, Satoshi; Ohta, Hisashi

    2011-11-21

    GPR61 is an orphan G protein-coupled receptor whose function remains unknown. The purpose of the present study is to elucidate the importance of GPR61 in metabolism by characterization of GPR61-deficient mice. Male GPR61-deficient mice were characterized regarding various metabolic parameters, including food intake, body weight, oxygen consumption, body temperature, locomotor activity, and in a pair feeding study. Hypothalamic gene expression was analyzed using real-time quantitative RT-PCR. GPR61-deficient mice exhibited marked hyperphagia and heavier body weight than wild-type mice. Hyperphagia of GPR61-deficient mice was observed before the differences in body weight became apparent between the genotypes. When body weight difference did become apparent between genotypes, increases in visceral fat pad weight, liver weight, liver triglyceride (TG) content, plasma leptin, and plasma insulin were observed in GPR61-deficient mice, suggesting that GPR61 deficiency caused obesity associated with hyperphagia. Oxygen consumption, body temperature, and locomotor activity were not significantly different between GPR61-deficient and wild-type mice. Pair-fed GPR61-deficient mice had a greater fat mass than wild-type mice despite comparable body weight in both genotypes. The mRNA levels of proopiomelanocortin (POMC) and brain-derived neurotropic factor (BDNF) in the hypothalamus of GPR61-deficient mice were significantly lower than those of wild-type mice. GPR61-deficient mice exhibited obesity associated with hyperphagia. These findings suggest that GPR61 is involved in the regulation of food intake and body weight, and may be of importance when considering GPR61 as a therapeutic target for obesity or eating disorders. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. Mice lacking p35, a neuronal specific activator of Cdk5, display cortical lamination defects, seizures, and adult lethality.

    PubMed

    Chae, T; Kwon, Y T; Bronson, R; Dikkes, P; Li, E; Tsai, L H

    1997-01-01

    The adult mammalian cortex is characterized by a distinct laminar structure generated through a well-defined pattern of neuronal migration. Successively generated neurons are layered in an "inside-out" manner to produce six cortical laminae. We demonstrate here that p35, the neuronal-specific activator of cyclin-dependent kinase 5, plays a key role in proper neuronal migration. Mice lacking p35, and thus p35/cdk5 kinase activity, display severe cortical lamination defects and suffer from sporadic adult lethality and seizures. Histological examination reveals that the mutant mice lack the characteristic laminated structure of the cortex. Neuronal birth-dating experiments indicate a reversed packing order of cortical neurons such that earlier born neurons reside in superficial layers and later generated neurons occupy deep layers. The phenotype of p35 mutant mice thus demonstrates that the formation of cortical laminar structure depends on the action of the p35/cdk5 kinase.

  17. Elevated pulmonary arterial pressure and altered expression of Ddah1 and Arg1 in mice lacking cavin-1/PTRF

    PubMed Central

    Swärd, Karl; Sadegh, Mardjaneh K; Mori, Michiko; Erjefält, Jonas S; Rippe, Catarina

    2013-01-01

    Caveolae are invaginations in the plasma membrane that depend on caveolins and cavins for maturation. Here, we investigated the pulmonary phenotype in mice lacking cavin-1. Bright field and electron-microscopy showed that the cavin-1-deficient mice lacked caveolae in the lung, had an increased lung tissue density, and exhibited hypertrophic remodeling of pulmonary arteries. The right ventricle of the heart moreover had an increased mass and the right ventricular pressure was elevated. A microarray analysis revealed upregulation of Arg1 and downregulation of Ddah1, molecules whose altered expression has previously been associated with pulmonary arterial hypertension. Taken together, this work demonstrates vascular remodeling and increased pulmonary blood pressure in cavin-1 deficient mice and associates this phenotype with altered expression of Arg1 and Ddah1. PMID:24303100

  18. Deficient liver regeneration after carbon tetrachloride injury in mice lacking type 1 but not type 2 tumor necrosis factor receptor.

    PubMed Central

    Yamada, Y.; Fausto, N.

    1998-01-01

    Signaling by tumor necrosis factor type 1 receptor (TNFR-1) is required for the initiation of liver regeneration after partial hepatectomy. Using knockout mice that lack either TNFR-1 or TNFR-2, we determined whether signaling through TNF receptors is important for liver injury and hepatocyte proliferation induced by carbon tetrachloride (CCl4). Lack of TNFR-1 inhibited hepatocyte DNA synthesis after CCl4 injection. At 44 hours after the injection, replication of hepatocytes in TNFR-1 was 50% to 90% lower than in wild-type (WT) animals, depending on the dose injected. In WT animals, hepatocyte replication was essentially completed by 4 days after CCl4 injection, but replication at a low level persisted in TNFR-1 mice for at least 2 weeks. TNFR-1 knockout mice had little detectable NF-kappa B and STAT3 binding during the first 5 hours after CCl4, high plasma TNF, and reduced levels of plasma interleukin (IL)-6 and liver IL-6 mRNA. Injection of IL-6 30 minutes before CCl4 administration corrected the deficiency of hepatocyte replication at 44 hours and restored STAT3 binding to normal levels. In contrast, mice lacking TNFR-2 did not differ significantly from WT mice in NF-kappa B and STAT3 binding, IL-6 and TNF levels, or hepatocyte replication. Although AP-1 binding was induced in WT TNFR-1 and TNFR-2 knockout mice, binding in TNFR-2 knockouts was lower than in WT mice. C/EBP binding was much lower in TNFR-1 and TNFR-2 knockout mice than in WT mice. As assessed by morphological analysis and alanine aminotransferase levels, the acute injury caused by CCl4 appeared to be similar in the three groups of animals, but subsequent regeneration was impaired in mice lacking TNFR-1. We conclude that a TNFR-1 signaling pathway involving NF-kappa B, IL-6, and STAT3 is an important component of the hepatocyte mitogenic response induced by CCl4 injury in mouse liver. Images Figure 2 Figure 4 Figure 6 Figure 8 Figure 9 Figure 10 Figure 12 PMID:9626061

  19. Myelin/oligodendrocyte glycoprotein–deficient (MOG-deficient) mice reveal lack of immune tolerance to MOG in wild-type mice

    PubMed Central

    Delarasse, Cécile; Daubas, Philippe; Mars, Lennart T.; Vizler, Csaba; Litzenburger, Tobias; Iglesias, Antonio; Bauer, Jan; Della Gaspera, Bruno; Schubart, Anna; Decker, Laurence; Dimitri, Dalia; Roussel, Guy; Dierich, Andrée; Amor, Sandra; Dautigny, André; Liblau, Roland; Pham-Dinh, Danielle

    2003-01-01

    We studied the immunological basis for the very potent encephalitogenicity of myelin/oligodendrocyte glycoprotein (MOG), a minor component of myelin in the CNS that is widely used to induce experimental autoimmune encephalomyelitis (EAE). For this purpose, we generated a mutant mouse lacking a functional mog gene. This MOG-deficient mouse presents no clinical or histological abnormalities, permitting us to directly assess the role of MOG as a target autoantigen in EAE. In contrast to WT mice, which developed severe EAE following immunization with whole myelin, MOG-deficient mice had a mild phenotype, demonstrating that the anti-MOG response is a major pathogenic component of the autoimmune response directed against myelin. Moreover, while MOG transcripts are expressed in lymphoid organs in minute amounts, both MOG-deficient and WT mice show similar T and B cell responses against the extracellular domain of MOG, including the immunodominant MOG 35–55 T cell epitope. Furthermore, no differences in the fine specificity of the T cell responses to overlapping peptides covering the complete mouse MOG sequence were observed between MOG+/+ and MOG–/– mice. In addition, upon adoptive transfer, MOG-specific T cells from WT mice and those from MOG-deficient mice are equally pathogenic. This total lack of immune tolerance to MOG in WT C57BL/6 mice may be responsible for the high pathogenicity of the anti-MOG immune response as well as the high susceptibility of most animal strains to MOG-induced EAE. PMID:12925695

  20. Mice Lacking Brinp2 or Brinp3, or Both, Exhibit Behaviors Consistent with Neurodevelopmental Disorders

    PubMed Central

    Berkowicz, Susan R.; Featherby, Travis J.; Whisstock, James C.; Bird, Phillip I.

    2016-01-01

    Background: Brinps 1–3, and Astrotactins (Astn) 1 and 2, are members of the Membrane Attack Complex/Perforin (MACPF) superfamily that are predominantly expressed in the mammalian brain during development. Genetic variation at the human BRINP2/ASTN1 and BRINP1/ASTN2 loci has been implicated in neurodevelopmental disorders. We, and others, have previously shown that Brinp1−/− mice exhibit behavior reminiscent of autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD). Method: We created Brinp2−/− mice and Brinp3−/− mice via the Cre-mediated LoxP system to investigate the effect of gene deletion on anatomy and behavior. Additionally, Brinp2−/−Brinp3−/− double knock-out mice were generated by interbreeding Brinp2−/− and Brinp3−/− mice. Genomic validation was carried out for each knock-out line, followed by histological, weight and behavioral examination. Brinp1−/−Brinp2−/−Brinp3−/− triple knock-out mice were also generated by crossing Brinp2/3 double knock-out mice with previously generated Brinp1−/− mice, and examined by weight and histological analysis. Results: Brinp2−/− and Brinp3−/− mice differ in their behavior: Brinp2−/− mice are hyperactive, whereas Brinp3−/− mice exhibit marked changes in anxiety-response on the elevated plus maze. Brinp3−/− mice also show evidence of altered sociability. Both Brinp2−/− and Brinp3−/− mice have normal short-term memory, olfactory responses, pre-pulse inhibition, and motor learning. The double knock-out mice show behaviors of Brinp2−/− and Brinp3−/− mice, without evidence of new or exacerbated phenotypes. Conclusion: Brinp3 is important in moderation of anxiety, with potential relevance to anxiety disorders. Brinp2 dysfunction resulting in hyperactivity may be relevant to the association of ADHD with chromosome locus 1q25.2. Brinp2−/− and Brinp3−/− genes do not compensate in the mammalian brain and likely have

  1. Absence of opioid stress-induced analgesia in mice lacking beta-endorphin by site-directed mutagenesis.

    PubMed Central

    Rubinstein, M; Mogil, J S; Japón, M; Chan, E C; Allen, R G; Low, M J

    1996-01-01

    A physiological role for beta-endorphin in endogenous pain inhibition was investigated by targeted mutagenesis of the proopiomelanocortin gene in mouse embryonic stem cells. The tyrosine codon at position 179 of the proopiomelanocortin gene was converted to a premature translational stop codon. The resulting transgenic mice display no overt developmental or behavioral alterations and have a normally functioning hypothalamic-pituitary-adrenal axis. Homozygous transgenic mice with a selective deficiency of beta-endorphin exhibit normal analgesia in response to morphine, indicating the presence of functional mu-opiate receptors. However, these mice lack the opioid (naloxone reversible) analgesia induced by mild swim stress. Mutant mice also display significantly greater nonopioid analgesia in response to cold water swim stress compared with controls and display paradoxical naloxone-induced analgesia. These changes may reflect compensatory upregulation of alternative pain inhibitory mechanisms. Images Fig. 1 Fig. 2 PMID:8633004

  2. Absence of opioid stress-induced analgesia in mice lacking beta-endorphin by site-directed mutagenesis.

    PubMed

    Rubinstein, M; Mogil, J S; Japón, M; Chan, E C; Allen, R G; Low, M J

    1996-04-30

    A physiological role for beta-endorphin in endogenous pain inhibition was investigated by targeted mutagenesis of the proopiomelanocortin gene in mouse embryonic stem cells. The tyrosine codon at position 179 of the proopiomelanocortin gene was converted to a premature translational stop codon. The resulting transgenic mice display no overt developmental or behavioral alterations and have a normally functioning hypothalamic-pituitary-adrenal axis. Homozygous transgenic mice with a selective deficiency of beta-endorphin exhibit normal analgesia in response to morphine, indicating the presence of functional mu-opiate receptors. However, these mice lack the opioid (naloxone reversible) analgesia induced by mild swim stress. Mutant mice also display significantly greater nonopioid analgesia in response to cold water swim stress compared with controls and display paradoxical naloxone-induced analgesia. These changes may reflect compensatory upregulation of alternative pain inhibitory mechanisms.

  3. Coagulation defects and altered hemodynamic responses in mice lacking receptors for thromboxane A2.

    PubMed Central

    Thomas, D W; Mannon, R B; Mannon, P J; Latour, A; Oliver, J A; Hoffman, M; Smithies, O; Koller, B H; Coffman, T M

    1998-01-01

    Thromboxane A2 (TXA2) is a labile metabolite of arachidonic acid that has potent biological effects. Its actions are mediated by G protein-coupled thromboxane-prostanoid (TP) receptors. TP receptors have been implicated in the pathogenesis of cardiovascular diseases. To investigate the physiological functions of TP receptors, we generated TP receptor-deficient mice by gene targeting. Tp-/- animals reproduce and survive in expected numbers, and their major organ systems are normal. Thromboxane agonist binding cannot be detected in tissues from Tp-/- mice. Bleeding times are prolonged in Tp-/- mice and their platelets do not aggregate after exposure to TXA2 agonists. Aggregation responses after collagen stimulation are also delayed, although ADP-stimulated aggregation is normal. Infusion of the TP receptor agonist U-46619 causes transient increases in blood pressure followed by cardiovascular collapse in wild-type mice, but U-46619 caused no hemodynamic effect in Tp-/- mice. Tp-/- mice are also resistant to arachidonic acid-induced shock, although arachidonic acid signifi-cantly reduced blood pressure in Tp-/- mice. In summary, Tp-/- mice have a mild bleeding disorder and altered vascular responses to TXA2 and arachidonic acid. Our studies suggest that most of the recognized functions of TXA2 are mediated by the single known Tp gene locus. PMID:9835625

  4. Diminished Paracrine Regulation of the Epithelial Na+ Channel by Purinergic Signaling in Mice Lacking Connexin 30*

    PubMed Central

    Mironova, Elena; Peti-Peterdi, Janos; Bugaj, Vladislav; Stockand, James D.

    2011-01-01

    We tested whether ATP release through Connexin 30 (Cx30) is part of a local purinergic regulatory system intrinsic to the aldosterone-sensitive distal nephron (ASDN) important for proper control of sodium excretion; if changes in sodium intake influence ATP release via Cx30; and if this allows a normal ENaC response to changes in systemic sodium levels. In addition, we define the consequences of disrupting ATP regulation of ENaC in Cx30−/− mice. Urinary ATP levels in wild-type mice increase with sodium intake, being lower and less dependent on sodium intake in Cx30−/− mice. Loss of inhibitory ATP regulation causes ENaC activity to be greater in Cx30−/− versus wild-type mice, particularly with high sodium intake. This results from compromised ATP release rather than end-organ resistance: ENaC in Cx30−/− mice responds to exogenous ATP. Thus, loss of paracrine ATP feedback regulation of ENaC in Cx30−/− mice disrupts normal responses to changes in sodium intake. Consequently, ENaC is hyperactive in Cx30−/− mice lowering sodium excretion particularly during increases in sodium intake. Clamping mineralocorticoids high in Cx30−/− mice fed a high sodium diet causes a marked decline in renal sodium excretion. This is not the case in wild-type mice, which are capable of undergoing aldosterone-escape. This loss of the ability of ENaC to respond to changes in sodium levels contributes to salt-sensitive hypertension in Cx30−/− mice. PMID:21075848

  5. Diminished paracrine regulation of the epithelial Na+ channel by purinergic signaling in mice lacking connexin 30.

    PubMed

    Mironova, Elena; Peti-Peterdi, Janos; Bugaj, Vladislav; Stockand, James D

    2011-01-14

    We tested whether ATP release through Connexin 30 (Cx30) is part of a local purinergic regulatory system intrinsic to the aldosterone-sensitive distal nephron (ASDN) important for proper control of sodium excretion; if changes in sodium intake influence ATP release via Cx30; and if this allows a normal ENaC response to changes in systemic sodium levels. In addition, we define the consequences of disrupting ATP regulation of ENaC in Cx30(-/-) mice. Urinary ATP levels in wild-type mice increase with sodium intake, being lower and less dependent on sodium intake in Cx30(-/-) mice. Loss of inhibitory ATP regulation causes ENaC activity to be greater in Cx30(-/-) versus wild-type mice, particularly with high sodium intake. This results from compromised ATP release rather than end-organ resistance: ENaC in Cx30(-/-) mice responds to exogenous ATP. Thus, loss of paracrine ATP feedback regulation of ENaC in Cx30(-/-) mice disrupts normal responses to changes in sodium intake. Consequently, ENaC is hyperactive in Cx30(-/-) mice lowering sodium excretion particularly during increases in sodium intake. Clamping mineralocorticoids high in Cx30(-/-) mice fed a high sodium diet causes a marked decline in renal sodium excretion. This is not the case in wild-type mice, which are capable of undergoing aldosterone-escape. This loss of the ability of ENaC to respond to changes in sodium levels contributes to salt-sensitive hypertension in Cx30(-/-) mice.

  6. Lack of Chronic Histologic Lesions Supportive of Sublethal Spontaneous Seizures in FVB/N Mice

    PubMed Central

    Kohnken, Rebecca A; Schwahn, Denise J

    2016-01-01

    FVB/N mice with ‘space cadet’ syndrome are prone to audiogenic seizures and are considered excitotoxic ‘sensitive’ mice due to the neuronal damage that accompanies seizures. FVB/N mice found dead demonstrate acute neuronal cell death—attributed to a massive seizure episode—within the hippocampus and cerebrocortical laminae. However, the behavioral features of FVB/N mice and numerous studies using excitotoxins to induce seizure activity indicate that this strain experiences multiple sublethal seizures. To assess whether FVB/N mice develop histologically detectable lesions, we evaluated the brains of 86 aged (154-847 d) FVB/N mice without a history of seizures. The hippocampus and cerebrocortical laminae were evaluated histologically for neuronal atrophy and gliosis. Neuronal atrophy was quantified by counting neurons in the hippocampus (CA3 and dentate gyrus) and cerebral cortex. Gliosis was quantified by using immunohistochemistry for glial fibrillary acidic protein and glial counting in the cerebral cortex. In addition, ventricular area was calculated. Our study revealed no changes in brain weight with age, no neuronal loss or gliosis, no correlation between neuronal or glial cell profile densities and brain weight or age, and no differences in ventricular size between FVB/N and control mice. Neuronal densities in the cerebral cortex and granule cells of the dentate gyrus were lower in FVB/N mice than in control Swiss Webster mice. We conclude that although acute lesions of seizure activity are a previous feature of the FVB/N strain, chronic seizure activity in these mice either is negligible or does not cause morphologic or phenotypic changes. PMID:27053564

  7. Anxiety-like behavior in mice lacking the angiotensin II type-2 receptor.

    PubMed

    Okuyama, S; Sakagawa, T; Chaki, S; Imagawa, Y; Ichiki, T; Inagami, T

    1999-03-06

    The main biological role of angiotensin II type 2 receptor (AT2) has not been established. We made use of targeted disruption of the mouse AT2 gene to examine the role of the AT2 receptor in the central nervous system (CNS). AT2-deficient mice displayed anxiety-like behavior compared with wild-type mice. However, AT2-deficient mice showed no depressant-like activity and no change in hexobarbital-induced sleeping time as compared with findings in wild-type mice. Both noradrenergic and corticotropin-releasing factor (CRF) neuronal systems appear to be involved in this anxiety-like behavior. Diazepam, captopril (angiotensin I converting enzyme inhibitor), prazosin (alpha1 antagonist) reversed the anxiety-like behavior in these AT2-deficient mice, whereas yohimbine (alpha2 antagonist), phenylephrine (alpha1 agonist), clonidine (alpha2 agonist), isoproterenol (beta1/beta2 agonist), propranolol (beta1/beta2 antagonist) and alpha-helical CRF9-41 (CRF receptor antagonist) has no apparent effects on anxiety-like behavior in AT2-deficient mice. In addition, concentrations of plasma adrenocorticotropic hormone (ACTH) and corticosterone in AT2-deficient mice did not differ from these in wild-type mice, hence, there are probably no endocrine abnormalities involving the hypothalamic-pituitary-adrenal axis (HPA). The amygdala appears to play an important role in many of the responses to fear and anxiety. The number of [3H]prazosin but not [125I]CRF binding sites in the amygdala was significantly reduced in AT2-deficient mice. These findings indicate that the noradrenergic system is involved in mediating the anxiety-like behavior in AT2-deficient mice. Copyright 1999 Elsevier Science B.V.

  8. Lack of tau proteins rescues neuronal cell death and decreases amyloidogenic processing of APP in APP/PS1 mice.

    PubMed

    Leroy, Karelle; Ando, Kunie; Laporte, Vincent; Dedecker, Robert; Suain, Valérie; Authelet, Michèle; Héraud, Céline; Pierrot, Nathalie; Yilmaz, Zehra; Octave, Jean-Noël; Brion, Jean-Pierre

    2012-12-01

    Lack of tau expression has been reported to protect against excitotoxicity and to prevent memory deficits in mice expressing mutant amyloid precursor protein (APP) identified in familial Alzheimer disease. In APP mice, mutant presenilin 1 (PS1) enhances generation of Aβ42 and inhibits cell survival pathways. It is unknown whether the deficient phenotype induced by concomitant expression of mutant PS1 is rescued by absence of tau. In this study, we have analyzed the effect of tau deletion in mice expressing mutant APP and PS1. Although APP/PS1/tau(+/+) mice had a reduced survival, developed spatial memory deficits at 6 months and motor impairments at 12 months, these deficits were rescued in APP/PS1/tau(-/-) mice. Neuronal loss and synaptic loss in APP/PS1/tau(+/+) mice were rescued in the APP/PS1/tau(-/-) mice. The amyloid plaque burden was decreased by roughly 50% in the cortex and the spinal cord of the APP/PS1/tau(-/-) mice. The levels of soluble and insoluble Aβ40 and Aβ42, and the Aβ42/Aβ40 ratio were reduced in APP/PS1/tau(-/-) mice. Levels of phosphorylated APP, of β-C-terminal fragments (CTFs), and of β-secretase 1 (BACE1) were also reduced, suggesting that β-secretase cleavage of APP was reduced in APP/PS1/tau(-/-) mice. Our results indicate that tau deletion had a protective effect against amyloid induced toxicity even in the presence of mutant PS1 and reduced the production of Aβ. Copyright © 2012 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  9. Mice that lack the C-terminal region of Reelin exhibit behavioral abnormalities related to neuropsychiatric disorders.

    PubMed

    Sakai, Kaori; Shoji, Hirotaka; Kohno, Takao; Miyakawa, Tsuyoshi; Hattori, Mitsuharu

    2016-06-27

    The secreted glycoprotein Reelin is believed to play critical roles in the pathogenesis of several neuropsychiatric disorders. The highly basic C-terminal region (CTR) of Reelin is necessary for efficient activation of its downstream signaling, and the brain structure of knock-in mice that lack the CTR (ΔC-KI mice) is impaired. Here, we performed a comprehensive behavioral test battery on ΔC-KI mice, in order to evaluate the effects of partial loss-of-function of Reelin on brain functions. The ΔC-KI mice were hyperactive and exhibited reduced anxiety-like and social behaviors. The working memory in ΔC-KI mice was impaired in a T-maze test. There was little difference in spatial reference memory, depression-like behavior, prepulse inhibition, or fear memory between ΔC-KI and wild-type mice. These results suggest that CTR-dependent Reelin functions are required for some specific normal brain functions and that ΔC-KI mice recapitulate some aspects of neuropsychiatric disorders, such as schizophrenia, bipolar disorder, and autism spectrum disorder.

  10. Mice that lack the C-terminal region of Reelin exhibit behavioral abnormalities related to neuropsychiatric disorders

    PubMed Central

    Sakai, Kaori; Shoji, Hirotaka; Kohno, Takao; Miyakawa, Tsuyoshi; Hattori, Mitsuharu

    2016-01-01

    The secreted glycoprotein Reelin is believed to play critical roles in the pathogenesis of several neuropsychiatric disorders. The highly basic C-terminal region (CTR) of Reelin is necessary for efficient activation of its downstream signaling, and the brain structure of knock-in mice that lack the CTR (ΔC-KI mice) is impaired. Here, we performed a comprehensive behavioral test battery on ΔC-KI mice, in order to evaluate the effects of partial loss-of-function of Reelin on brain functions. The ΔC-KI mice were hyperactive and exhibited reduced anxiety-like and social behaviors. The working memory in ΔC-KI mice was impaired in a T-maze test. There was little difference in spatial reference memory, depression-like behavior, prepulse inhibition, or fear memory between ΔC-KI and wild-type mice. These results suggest that CTR-dependent Reelin functions are required for some specific normal brain functions and that ΔC-KI mice recapitulate some aspects of neuropsychiatric disorders, such as schizophrenia, bipolar disorder, and autism spectrum disorder. PMID:27346785

  11. Mice lacking Smad3 are protected against cutaneous injury induced by ionizing radiation.

    PubMed

    Flanders, Kathleen C; Sullivan, Catherine D; Fujii, Makiko; Sowers, Anastasia; Anzano, Mario A; Arabshahi, Alidad; Major, Christopher; Deng, Chuxia; Russo, Angelo; Mitchell, James B; Roberts, Anita B

    2002-03-01

    Transforming growth factor-beta (TGF-beta) plays a central role in the pathogenesis of inflammatory and fibrotic diseases, including radiation-induced fibrosis. We previously reported that mice null for Smad3, a key downstream mediator of TGF-beta, show accelerated healing of cutaneous incisional wounds with reduced inflammation and accumulation of matrix. To determine if loss of Smad3 decreases radiation-induced injury, skin of Smad3+/+ [wild-type (WT)] and -/- [knockout (KO)] mice was exposed to a single dose of 30 to 50 Gy of gamma-irradiation. Six weeks later, skin from KO mice showed significantly less epidermal acanthosis and dermal influx of mast cells, macrophages, and neutrophils than skin from WT littermates. Skin from irradiated KO mice exhibited less immunoreactive TGF-beta and fewer myofibroblasts, suggesting that these mice will have a significantly reduced fibrotic response. Although irradiation induced no change in the immunohistochemical expression of the TGF-beta type I receptor, the epidermal expression of the type II receptor was lost after irradiation whereas its dermal expression remained high. Primary keratinocytes and dermal fibroblasts prepared from WT and KO mice showed similar survival when irradiated, as did mice exposed to whole-body irradiation. These results suggest that inhibition of Smad3 might decrease tissue damage and reduce fibrosis after exposure to ionizing irradiation.

  12. Nephrogenic diabetes insipidus in mice lacking all nitric oxide synthase isoforms

    PubMed Central

    Morishita, Tsuyoshi; Tsutsui, Masato; Shimokawa, Hiroaki; Sabanai, Ken; Tasaki, Hiromi; Suda, Osamu; Nakata, Sei; Tanimoto, Akihide; Wang, Ke-Yong; Ueta, Yoichi; Sasaguri, Yasuyuki; Nakashima, Yasuhide; Yanagihara, Nobuyuki

    2005-01-01

    Nitric oxide (NO) is produced in almost all tissues and organs, exerting a variety of biological actions under physiological and pathological conditions. NO is synthesized by three different isoforms of NO synthase (NOS), including neuronal, inducible, and endothelial NOSs. Because there are substantial compensatory interactions among the NOS isoforms, the ultimate roles of endogenous NO in our body still remain to be fully elucidated. Here, we have successfully developed mice in which all three NOS genes are completely deleted by crossbreeding singly NOS-/- mice. NOS expression and activities were totally absent in the triply NOS-/- mice before and after treatment with lipopolysaccharide. Although the triply NOS-/- mice were viable and appeared normal, their survival and fertility rates were markedly reduced as compared with the wild-type mice. Furthermore, these mice exhibited marked hypotonic polyuria, polydipsia, and renal unresponsiveness to an antidiuretic hormone, vasopressin, all of which are characteristics consistent with nephrogenic diabetes insipidus. In the kidney of the triply NOS-/- mice, vasopressin-induced cAMP production and membranous aquaporin-2 water channel expression were reduced associated with tubuloglomerular lesion formation. These results provide evidence that the NOS system plays a critical role in maintaining homeostasis, especially in the kidney. PMID:16024729

  13. Increased beta -oxidation but no insulin resistance or glucose intolerance in mice lacking adiponectin.

    PubMed

    Ma, Ke; Cabrero, Agatha; Saha, Pradip K; Kojima, Hideto; Li, Lan; Chang, Benny Hung-Junn; Paul, Antoni; Chan, Lawrence

    2002-09-20

    Previous reports showed that recombinant fragments of adiponectin (adipo) displayed pharmacological effects when injected into rodents, but the relevance of these observations to the physiological function of adipo is unclear. We generated Adipo(-/-) mice by gene targeting. Adipo(-/-) mice are fertile with normal body and fat pad weights. Plasma glucose and insulin levels of Adipo(-/-) and Adipo(+/+) mice are similar under fasting conditions and during an intraperitoneal glucose tolerance test (GTT). Insulin tolerance test (ITT) also produces similar plasma glucose and insulin levels in the two groups of mice. Hyperinsulinemic-euglycemic clamp analysis showed that Adipo(-/-) and Adipo(+/+) mice have similar glucose infusion rates to maintain a similar serum glucose. High-fat diet feeding for 7 months led to similar weight gain and similar GTT and ITT responses. We next measured beta-oxidation and found it to be significantly increased in muscle and liver of Adipo(-/-) mice. In conclusion, our study indicates that absence of adipo causes increased beta-oxidation but does not cause glucose intolerance or insulin resistance in mice.

  14. Hyperleptinemia without Obesity in Male Mice Lacking Androgen Receptor in Adipose Tissue

    PubMed Central

    Yu, I-Chen; Lin, Hung-Yun; Liu, Ning-Chun; Wang, Ruey-Shen; Sparks, Janet D.; Yeh, Shuyuan; Chang, Chawnshang

    2008-01-01

    Insulin resistance occurs through an inadequate response to insulin by insulin target organs such as liver, muscle, and adipose tissue with consequent insufficient glucose uptake. In previous studies we demonstrated that whole body androgen receptor (AR) knockout (AR−/y) mice develop obesity and exhibit insulin and leptin resistance at advanced age. By examining adipose tissue-specific AR knockout (A-AR−/y) mice, we found A-AR−/y mice were hyperleptinemic but showed no leptin resistance, although body weight and adiposity index of A-AR−/y mice were identical with those of male wild-type control mice. Hypotriglyceridemia and hypocholesterolemia found in nonobese A-AR−/y mice suggested a beneficial effect of high leptin levels independent of fat deposition. Further examination showed that androgen-AR signaling in adipose tissue plays a direct regulatory role in leptin expression via enhanced estrogen receptor transactivation activity due to elevated intraadipose estrogens. The present study in A-AR−/y mice suggests a differential tissue-specific role of AR in energy balance control in males. PMID:18276764

  15. Hyperleptinemia without obesity in male mice lacking androgen receptor in adipose tissue.

    PubMed

    Yu, I-Chen; Lin, Hung-Yun; Liu, Ning-Chun; Wang, Ruey-Shen; Sparks, Janet D; Yeh, Shuyuan; Chang, Chawnshang

    2008-05-01

    Insulin resistance occurs through an inadequate response to insulin by insulin target organs such as liver, muscle, and adipose tissue with consequent insufficient glucose uptake. In previous studies we demonstrated that whole body androgen receptor (AR) knockout (AR(-/y)) mice develop obesity and exhibit insulin and leptin resistance at advanced age. By examining adipose tissue-specific AR knockout (A-AR(-/y)) mice, we found A-AR(-/y) mice were hyperleptinemic but showed no leptin resistance, although body weight and adiposity index of A-AR(-/y) mice were identical with those of male wild-type control mice. Hypotriglyceridemia and hypocholesterolemia found in nonobese A-AR(-/y) mice suggested a beneficial effect of high leptin levels independent of fat deposition. Further examination showed that androgen-AR signaling in adipose tissue plays a direct regulatory role in leptin expression via enhanced estrogen receptor transactivation activity due to elevated intraadipose estrogens. The present study in A-AR(-/y) mice suggests a differential tissue-specific role of AR in energy balance control in males.

  16. Coxsackievirus B 1-induced polymyositis. Lack of disease expression in nu/nu mice.

    PubMed Central

    Ytterberg, S R; Mahowald, M L; Messner, R P

    1987-01-01

    Chronic inflammatory myositis similar to human polymyositis occurs in mice after infection with a strain of Coxsackievirus B 1 (CVB 1). To investigate the role of T cells in the pathogenesis of this disorder, we compared disease expression in T cell-deficient athymic nude (nu/nu) mice and heterozygotes (nu/+) with normal T cell function. Acute infectious myositis occurred in nu/nu and nu/+ mice. Chronic (greater than 21 d postinfection) weakness and myositis, however, developed only in nu/+. Resistance to disease in nu/nu mice was not explained by insusceptibility to infection; the amount of virus lethal for 50% of mice and virus replication were comparable in both groups. Additionally, anti-CVB 1 antibody production was similar in both groups. Reconstitution of infected nu/nu mice with spleen cells from normal mice resulted in disease. These results demonstrate that chronic weakness after infection with this virus is not simply a sequela of acute myonecrosis and suggest that T cells play a pivotal role in the pathogenesis of chronic myositis. Images PMID:3038960

  17. Quantitative Proteomics of Intestinal Mucosa From Male Mice Lacking Intestinal Epithelial Insulin Receptors.

    PubMed

    Jensen, Stina Rikke; Schoof, Erwin M; Wheeler, Sarah E; Hvid, Henning; Ahnfelt-Rønne, Jonas; Hansen, Bo Falck; Nishimura, Erica; Olsen, Grith Skytte; Kislinger, Thomas; Brubaker, Patricia L

    2017-08-01

    The goal of the present study was to determine whether loss of the insulin receptor alters the molecular landscape of the intestinal mucosa, using intestinal-epithelial insulin receptor knockout (IE-irKO) mice and both genetic (IRfl/fl and Villin-cre) controls. Quantitative proteomic analysis by liquid chromatography mass spectrometry was applied to jejunal and colonic mucosa from mice fed a normal chow diet and mice fed a Western diet (WD). Jejunal mucosa from IE-irKO mice demonstrated alterations in all intestinal cell lineages: Paneth, goblet, absorptive, and enteroendocrine cells. Only goblet and absorptive cells were affected in the colon. Also, a marked effect of WD consumption was found on the gut proteome. A substantial reduction was detected in Paneth cell proteins with antimicrobial activity, including lysozyme C-1, angiogenin-4, cryptdin-related sequence 1C-3 and -2, α-defensin 17, and intelectin-1a. The key protein expressed by goblet cells, mucin-2, was also reduced in the IE-irKO mice. Proteins involved in lipid metabolism, including aldose reductase-related protein 1, 15-hydroxyprostaglandin dehydrogenase, apolipoprotein A-II, and pyruvate dehydrogenase kinase isozyme 4, were increased in the mucosa of WD-fed IE-irKO mice compared with controls. In contrast, expression of the nutrient-responsive gut hormones, glucose-dependent insulinotropic polypeptide and neurotensin, was reduced in the jejunal mucosa of IE-irKO mice, and the expression of proteins of the P-type adenosine triphosphatases and the solute carrier-transporter family was reduced in the colon of WD-fed IE-irKO mice. In conclusion, IE-irKO mice display a distinct molecular phenotype, suggesting a biological role of insulin and its receptor in determining differentiated cell specificity in the intestinal epithelium. Copyright © 2017 Endocrine Society.

  18. Lack of MAP Kinase Phosphatase-1 Protects ApoE-null Mice against Atherosclerosis

    PubMed Central

    Shen, Jianzhong; Chandrasekharan, Unni M.; Ashraf, Mohammad Z.; Long, Eric; Morton, Richard E.; Liu, Yusen; Smith, Jonathan D.; DiCorleto, Paul E.

    2010-01-01

    Rationale Multiple protein kinases have been implicated in cardiovascular disease; however, little is known about the role of their counterparts — the protein phosphatases. Objective To test the hypothesis that Mitogen-Activated Protein Kinase Phosphatase-1 (MKP-1) is actively involved in atherogenesis. Methods and Results Mice with homozygous deficiency in MKP-1 (MKP-1−/−) were bred with ApoE-deficient mice (ApoE−/−) and the three MKP-1 genotypes (MKP-1+/+ /ApoE−/−; MKP-1+/− /ApoE−/− and MKP-1−/− /ApoE−/−) were maintained on a normal chow diet for 16-week. The three groups of mice exhibited similar body weight and serum lipid profiles; however, both MKP-1+/− and MKP-1−/− mice had significantly less aortic root atherosclerotic lesion formation than MKP-1+/+ mice. Less en face lesion was observed in 8-month old MKP-1−/− mice. The reduction in atherosclerosis was accompanied by decreased plasma levels of IL-1α and TNFα, and preceded by increased anti-inflammatory cytokine IL-10. In addition, MKP-1-null mice had higher levels of plasma SDF-1α, which negatively correlated with atherosclerotic lesion size. Immuno-histochemical analysis revealed that MKP-1 expression was enriched in macrophage-rich areas versus smooth muscle cell regions of the atheroma. Furthermore, macrophages isolated from MKP-1-null mice showed dramatic defects in their spreading/migration and impairment in ERK, but not JNK and p38, pathway activation. In line with this, MKP-1-null atheroma exhibited less macrophage content. Finally, transplantation of MKP-1-intact bone marrow into MKP-1-null mice fully rescued the wild type atherosclerotic phenotype. Conclusion These findings demonstrate that chronic deficiency of MKP-1 leads to decreased atherosclerosis via mechanisms involving impaired macrophage migration and defective ERK signalling. PMID:20093631

  19. Sleep and Sleep Homeostasis in Mice Lacking the 5-HT2c Receptor

    PubMed Central

    Frank, Marcos G.; Stryker, Michael P.; Tecott, Laurence H.

    2008-01-01

    Studies in humans and rats indicate that serotonin (5-hydroxytryptamine, 5-HT) receptors are involved in mammalian sleep expression. We investigated the contribution of the 5-HT2c receptor to sleep expression by examining sleep patterns in mice bearing a targeted null mutation of this receptor. 5-HT2c receptor knock-out mice had more wakefulness, several abnormalities in rapid eye movement sleep expression and an enhanced response to sleep deprivation compared with wild-type control mice. These findings suggest that 5HT2c receptors may mediate several effects on sleep that have been ascribed to serotonin. PMID:12431861

  20. Increased Learning and Brain Long-Term Potentiation in Aged Mice Lacking DNA Polymerase μ

    PubMed Central

    Lucas, Daniel; Delgado-García, José M.; Escudero, Beatriz; Albo, Carmen; Aza, Ana; Acín-Pérez, Rebeca; Torres, Yaima; Moreno, Paz; Enríquez, José Antonio; Samper, Enrique; Blanco, Luis; Fairén, Alfonso

    2013-01-01

    A definitive consequence of the aging process is the progressive deterioration of higher cognitive functions. Defects in DNA repair mechanisms mostly result in accelerated aging and reduced brain function. DNA polymerase µ is a novel accessory partner for the non-homologous end-joining DNA repair pathway for double-strand breaks, and its deficiency causes reduced DNA repair. Using associative learning and long-term potentiation experiments, we demonstrate that Polµ−/− mice, however, maintain the ability to learn at ages when wild-type mice do not. Expression and biochemical analyses suggest that brain aging is delayed in Polµ−/− mice, being associated with a reduced error-prone DNA oxidative repair activity and a more efficient mitochondrial function. This is the first example in which the genetic ablation of a DNA-repair function results in a substantially better maintenance of learning abilities, together with fewer signs of brain aging, in old mice. PMID:23301049

  1. Time-place learning and memory persist in mice lacking functional Per1 and Per2 clock genes.

    PubMed

    Mulder, C; Van Der Zee, E A; Hut, R A; Gerkema, M P

    2013-12-01

    With time-place learning, animals link a stimulus with the location and the time of day. This ability may optimize resource localization and predator avoidance in daily changing environments. Time-place learning is a suitable task to study the interaction of the circadian system and memory. Previously, we showed that time-place learning in mice depends on the circadian system and Cry1 and/or Cry2 clock genes. We questioned whether time-place learning is Cry specific or also depends on other core molecular clock genes. Here, we show that Per1/Per2 double mutant mice, despite their arrhythmic phenotype, acquire time-place learning similar to wild-type mice. As well as an established role in circadian rhythms, Per genes have also been implicated in the formation and storage of memory. We found no deficiencies in short-term spatial working memory in Per mutant mice compared to wild-type mice. Moreover, both Per mutant and wild-type mice showed similar long-term memory for contextual features of a paradigm (a mild foot shock), measured in trained mice after a 2-month nontesting interval. In contrast, time-place associations were lost in both wild-type and mutant mice after these 2 months, suggesting a lack of maintained long-term memory storage for this type of information. Taken together, Cry-dependent time-place learning does not require Per genes, and Per mutant mice showed no PER-specific short-term or long-term memory deficiencies. These results limit the functional role of Per clock genes in the circadian regulation of time-place learning and memory.

  2. Dental and Cranial Pathologies in Mice Lacking the Cl−/H+-Exchanger ClC-7

    PubMed Central

    WEN, Xin; LACRUZ, Rodrigo S.; PAINE, Michael L.

    2015-01-01

    ClC-7 is a 2Cl−/1H+-exchanger expressed at late endosomes and lysosomes, as well as the ruffled border of osteoclasts. ClC-7 deficiencies in mice and humans lead to impaired osteoclast function and therefore osteopetrosis. Failure of tooth eruption is also apparent in ClC-7 mutant animals, and this has been attributed to the osteoclast dysfunction and the subsequent defect in alveolar bone resorptive activity surrounding tooth roots. Ameloblasts also express ClC-7, and this study aims to determine the significance of ClC-7 in enamel formation by examining the dentitions of ClC-7 mutant mice. Micro-CT analysis revealed that the molar teeth of 3-week old ClC-7 mutant mice had no roots, and the incisors were smaller than their age-matched controls. Despite these notable developmental differences, the enamel and dentin densities of the mutant mice were comparable to those of the wild type littermates. Scanning electron microscopy (SEM) showed normal enamel crystallite and prismatic organization in the ClC-7 mutant mice, although the enamel was thinner (hypoplastic) than in controls. These results suggested that ClC-7 was not critical to enamel and dentin formation, and the observed tooth defects may be related more to a resulting alveolar bone phenotype. Micro-CT analysis also revealed abnormal features in the calvarial bones of the mutant mice. The cranial sutures in ClC-7 mutant mice remained open compared to the closed sutures seen in the control mice at 3 weeks. These data demonstrate that ClC-7 deficiency impacts the development of the dentition and calvaria, but does not significantly disrupt amelogenesis. PMID:25663454

  3. Characterization of spontaneous air space enlargement in mice lacking microfibrillar-associated protein 4.

    PubMed

    Holm, Anne Trommelholt; Wulf-Johansson, Helle; Hvidsten, Svend; Jorgensen, Patricia Troest; Schlosser, Anders; Pilecki, Bartosz; Ormhøj, Maria; Moeller, Jesper Bonnet; Johannsen, Claus; Baun, Christina; Andersen, Thomas; Schneider, Jan Philipp; Hegermann, Jan; Ochs, Matthias; Götz, Alexander A; Schulz, Holger; de Angelis, Martin Hrabě; Vestbo, Jørgen; Holmskov, Uffe; Sorensen, Grith Lykke

    2015-06-01

    Microfibrillar-associated protein 4 (MFAP4) is localized to elastic fibers in blood vessels and the interalveolar septa of the lungs and is further present in bronchoalveolar lavage. Mfap4 has been previously suggested to be involved in elastogenesis in the lung. We tested this prediction and aimed to characterize the pulmonary function changes and emphysematous changes that occur in Mfap4-deficient (Mfap4(-/-)) mice. Significant changes included increases in total lung capacity and compliance, which were evident in Mfap4(-/-) mice at 6 and 8 mo but not at 3 mo of age. Using in vivo breath-hold gated microcomputed tomography (micro-CT) in 8-mo-old Mfap4(-/-) mice, we found that the mean density of the lung parenchyma was decreased, and the low-attenuation area (LAA) was significantly increased by 14% compared with Mfap4(+/+) mice. Transmission electron microscopy (TEM) did not reveal differences in the organization of elastic fibers, and there was no difference in elastin content, but a borderline significant increase in elastin mRNA expression in 3-mo-old mice. Stereological analysis showed that alveolar surface density in relation to the lung parenchyma and total alveolar surface area inside of the lung were both significantly decreased in Mfap4(-/-) mice by 25 and 15%, respectively. The data did not support an essential role of MFAP4 in pulmonary elastic fiber organization or content but indicated increased turnover in young Mfap4(-/-) mice. However, Mfap4(-/-) mice developed a spontaneous loss of lung function, which was evident at 6 mo of age, and moderate air space enlargement, with emphysema-like changes.

  4. Dental and Cranial Pathologies in Mice Lacking the Cl(-) /H(+) -Exchanger ClC-7.

    PubMed

    Wen, Xin; Lacruz, Rodrigo S; Paine, Michael L

    2015-08-01

    ClC-7 is a 2Cl(-) /1H(+) -exchanger expressed at late endosomes and lysosomes, as well as the ruffled border of osteoclasts. ClC-7 deficiencies in mice and humans lead to impaired osteoclast function and therefore osteopetrosis. Failure of tooth eruption is also apparent in ClC-7 mutant animals, and this has been attributed to the osteoclast dysfunction and the subsequent defect in alveolar bone resorptive activity surrounding tooth roots. Ameloblasts also express ClC-7, and this study aims to determine the significance of ClC-7 in enamel formation by examining the dentitions of ClC-7 mutant mice. Micro-CT analysis revealed that the molar teeth of 3-week old ClC-7 mutant mice had no roots, and the incisors were smaller than their age-matched controls. Despite these notable developmental differences, the enamel and dentin densities of the mutant mice were comparable to those of the wild-type littermates. Scanning electron microscopy showed normal enamel crystallite and prismatic organization in the ClC-7 mutant mice, although the enamel was thinner (hypoplastic) than in controls. These results suggested that ClC-7 was not critical to enamel and dentin formation, and the observed tooth defects may be related more to a resulting alveolar bone phenotype. Micro-CT analysis also revealed abnormal features in the calvarial bones of the mutant mice. The cranial sutures in ClC-7 mutant mice remained open compared to the closed sutures seen in the control mice at 3 weeks. These data demonstrate that ClC-7 deficiency impacts the development of the dentition and calvaria, but does not significantly disrupt amelogenesis.

  5. Lack of skeletal muscle IL-6 influences hepatic glucose metabolism in mice during prolonged exercise.

    PubMed

    Bertholdt, Lærke; Gudiksen, Anders; Schwartz, Camilla L; Knudsen, Jakob G; Pilegaard, Henriette

    2017-04-01

    The liver is essential in maintaining and regulating glucose homeostasis during prolonged exercise. IL-6 has been shown to be secreted from skeletal muscle during exercise and has been suggested to signal to the liver. Therefore, the aim of this study was to investigate the role of skeletal muscle IL-6 on hepatic glucose regulation and substrate choice during prolonged exercise. Skeletal muscle-specific IL-6 knockout (IL-6 MKO) mice (age, 12-14 wk) and littermate lox/lox (Control) mice were either rested (Rest) or completed a single bout of exercise for 10, 60, or 120 min, and the liver was quickly obtained. Hepatic IL-6 mRNA was higher at 60 min of exercise, and hepatic signal transducer and activator of transcription 3 was higher at 120 min of exercise than at rest in both genotypes. Hepatic glycogen was higher in IL-6 MKO mice than control mice at rest, but decreased similarly during exercise in the two genotypes, and hepatic glucose content was lower in IL-6 MKO than control mice at 120 min of exercise. Hepatic phosphoenolpyruvate carboxykinase mRNA and protein increased in both genotypes at 120 min of exercise, whereas hepatic glucose 6 phosphatase protein remained unchanged. Furthermore, IL-6 MKO mice had higher hepatic pyruvate dehydrogenase (PDH)(Ser232) and PDH(Ser300) phosphorylation than control mice at rest. In conclusion, hepatic gluconeogenic capacity in mice is increased during prolonged exercise independent of muscle IL-6. Furthermore, Skeletal muscle IL-6 influences hepatic substrate regulation at rest and hepatic glucose metabolism during prolonged exercise, seemingly independent of IL-6 signaling in the liver. Copyright © 2017 the American Physiological Society.

  6. Age-dependent changes in contractile function and passive elastic properties of myocardium from mice lacking muscle LIM protein (MLP).

    PubMed

    Unsöld, Bernhard; Schotola, Hanna; Jacobshagen, Claudius; Seidler, Tim; Sossalla, Samuel; Emons, Julius; Klede, Stefanie; Knöll, Ralph; Guan, Kaomei; El-Armouche, Ali; Linke, Wolfgang A; Kögler, Harald; Hasenfuss, Gerd

    2012-04-01

    Muscle LIM protein (MLP) null mice are often used as a model for human dilated cardiomyopathy. So far, little is known about the time course and pathomechanisms leading to the development of the adult phenotype. We systematically analysed the contractile phenotype, myofilament calcium (Ca(2)(+)) responsiveness, passive myocardial mechanics, histology, and mRNA expression in mice aged 4 and 12 weeks. In 4-week-old animals, there was no significant difference in the force-frequency relationship (FFR) and catecholamine response of intact isolated papillary muscles between wild-type (WT) and MLP null myocardium. In 12-week-old animals, WT myocardium exhibited a significantly positive FFR, while that of MLP null mice was significantly negative, and the inotropic response to catecholamines was significantly reduced in MLP null mice. This time course of decline in contractile function was confirmed in vivo by echocardiography. Whereas at 4 weeks of age MLP null mice and WT littermates showed similar levels of SERCA2a (sarcoplasmic reticulum Ca(2+) ATPase) expression, the expression was significantly lower in 12-week-old MLP null mice compared with littermate controls. Myofilament Ca(2)(+) responsiveness was not affected by the lack of MLP, irrespective of age. Whereas in 4-week-old animals MLP null myocardium showed a trend to an increased compliance compared with the WT, myocardium of 12-week-old MLP null mice was significantly less compliant than WT myocardium. Parallel to the decrease in compliance there was an increase in fibrosis in the MLP null animals. Our data suggest that MLP deficiency does not primarily influence myocardial contractility. A lack of MLP leads to an age-dependent impairment of excitation-contraction coupling with resulting contractile dysfunction and secondary fibrosis.

  7. The vitamin D analog ZK191784 normalizes decreased bone matrix mineralization in mice lacking the calcium channel TRPV5.

    PubMed

    van der Eerden, Bram C J; Fratzl-Zelman, Nadja; Nijenhuis, Tom; Roschger, Paul; Zügel, Ulrich; Steinmeyer, Andreas; Hoenderop, Joost G J; Bindels, René J M; Klaushofer, Klaus; van Leeuwen, Johannes P T M

    2013-02-01

    Mice lacking the renal epithelial Ca(2+) channel TRPV5 (TRPV5(-/-)) display impaired renal Ca(2+) reabsorption, hypercalciuria, and intestinal Ca(2+) hyperabsorption, due to secondary hypervitaminosis D. Using these mice, we previously demonstrated that ZK191784 acts as an intestine-specific 1,25(OH)(2) D(3) antagonist without affecting serum calcium levels. On the other hand, it acted as an agonist in the kidney and the effects of ZK191784 on bone were ambiguous. The present study was undertaken to further evaluate the effect of the vitamin D receptor antagonist on murine bone in mice lacking TRPV5. Eight-week-old female Trpv5(+/+) and Trpv5(-/-) mice were treated for 4 weeks with or without 50 µg/kg/day ZK191784. Quantitative backscattered electron imaging showed that the reduced bone matrix mineralization found in femoral bones of Trpv5(-/-) mice was partially but significantly restored upon ZK191784 treatment, just as we observed for trabecular bone thickness. This supports the significance of 1,25(OH)(2) D(3) and optimal control of Ca(2+) homeostasis for bone formation and matrix mineralization. Restoration also took place at the bone gene expression level, where 1α-hydroxylase (Cyp27b1) mRNA in femurs from ZK-treated Trpv5(-/-) mice was upregulated compared to control levels. The downregulated 24-hydroxylase (Cyp24a1) gene expression in femoral bone indicated local vitamin D resistance in the mice treated with ZK191784. Phosphate homeostasis was unaffected between the groups as shown by unaltered serum PO(4)(3-) and fibroblast growth factor (FGF) 23 as well as Fgf23 mRNA expression in bone. In conclusion, circulating 1,25(OH)(2) D(3) is important for optimal control of Ca(2+) homeostasis but also for controlled bone formation and matrix mineralization.

  8. Synaptic dysfunction and abnormal behaviors in mice lacking major isoforms of Shank3.

    PubMed

    Wang, Xiaoming; McCoy, Portia A; Rodriguiz, Ramona M; Pan, Yanzhen; Je, H Shawn; Roberts, Adam C; Kim, Caroline J; Berrios, Janet; Colvin, Jennifer S; Bousquet-Moore, Danielle; Lorenzo, Isabel; Wu, Gangyi; Weinberg, Richard J; Ehlers, Michael D; Philpot, Benjamin D; Beaudet, Arthur L; Wetsel, William C; Jiang, Yong-Hui

    2011-08-01

    SHANK3 is a synaptic scaffolding protein enriched in the postsynaptic density (PSD) of excitatory synapses. Small microdeletions and point mutations in SHANK3 have been identified in a small subgroup of individuals with autism spectrum disorder (ASD) and intellectual disability. SHANK3 also plays a key role in the chromosome 22q13.3 microdeletion syndrome (Phelan-McDermid syndrome), which includes ASD and cognitive dysfunction as major clinical features. To evaluate the role of Shank3 in vivo, we disrupted major isoforms of the gene in mice by deleting exons 4-9. Isoform-specific Shank3(e4-9) homozygous mutant mice display abnormal social behaviors, communication patterns, repetitive behaviors and learning and memory. Shank3(e4-9) male mice display more severe impairments than females in motor coordination. Shank3(e4-9) mice have reduced levels of Homer1b/c, GKAP and GluA1 at the PSD, and show attenuated activity-dependent redistribution of GluA1-containing AMPA receptors. Subtle morphological alterations in dendritic spines are also observed. Although synaptic transmission is normal in CA1 hippocampus, long-term potentiation is deficient in Shank3(e4-9) mice. We conclude that loss of major Shank3 species produces biochemical, cellular and morphological changes, leading to behavioral abnormalities in mice that bear similarities to human ASD patients with SHANK3 mutations.

  9. Plasma cholesterol-lowering and transient liver dysfunction in mice lacking squalene synthase in the liver.

    PubMed

    Nagashima, Shuichi; Yagyu, Hiroaki; Tozawa, Ryuichi; Tazoe, Fumiko; Takahashi, Manabu; Kitamine, Tetsuya; Yamamuro, Daisuke; Sakai, Kent; Sekiya, Motohiro; Okazaki, Hiroaki; Osuga, Jun-ichi; Honda, Akira; Ishibashi, Shun

    2015-05-01

    Squalene synthase (SS) catalyzes the biosynthesis of squalene, the first specific intermediate in the cholesterol biosynthetic pathway. To test the feasibility of lowering plasma cholesterol by inhibiting hepatic SS, we generated mice in which SS is specifically knocked out in the liver (L-SSKO) using Cre-loxP technology. Hepatic SS activity of L-SSKO mice was reduced by >90%. In addition, cholesterol biosynthesis in the liver slices was almost eliminated. Although the hepatic squalene contents were markedly reduced in L-SSKO mice, the hepatic contents of cholesterol and its precursors distal to squalene were indistinguishable from those of control mice, indicating the presence of sufficient centripetal flow of cholesterol and/or its precursors from the extrahepatic tissues. L-SSKO mice showed a transient liver dysfunction with moderate hepatomegaly presumably secondary to increased farnesol production. In a fed state, the plasma total cholesterol and triglyceride were significantly reduced in L-SSKO mice, primarily owing to reduced hepatic VLDL secretion. In a fasted state, the hypolipidemic effect was lost. mRNA expression of liver X receptor α target genes was reduced, while that of sterol-regulatory element binding protein 2 target genes was increased. In conclusion, liver-specific ablation of SS inhibits hepatic cholesterol biosynthesis and induces hypolipidemia without increasing significant mortality.

  10. Object Phobia and Altered RhoA Signaling in Amygdala of Mice Lacking RICH2

    PubMed Central

    Sarowar, Tasnuva; Grabrucker, Stefanie; Boeckers, Tobias M.; Grabrucker, Andreas M.

    2017-01-01

    RICH2 knockout (RICH2 KO) mice exhibit neophobia in the novel object test. To gain further insight into their anxiety-related phenotype, we subjected these mice to additional behavioral tests to elucidate whether the behavioral abnormality in these mice is a consequence of reduced exploratory motivation, and whether the neophobia is linked specifically to objects or also present for other modalities. RICH2 KO mice engage in normal exploration in a novel environment, suggesting that the anxiety-related phenotype is not due to reduced exploratory drive. Increased fear response was not observed using novel olfactory cues, but restricted to objects. Given that the amygdala is an important brain region mediating anxiety-related behaviors and a prime target for anxiety-related therapeutics, and RICH2 is a Rho-GTPase activating protein (GAP) regulating synaptic spine plasticity via small GTPases, we analyzed spine formation, morphology and receptor composition in amygdala. We found disinhibition of RhoA in the amygdala of RICH2 KO mice, along with a decreased ability for actin polymerization and a reduction in mature spines. However, we detected increased neuronal activation in the amygdala evidenced by c-fos labeling. Thus, we conclude that despite unaltered baseline activity, RICH2 KO mice show heightened amygdala response after exposure to objects, which, however, does not result in homeostatic strengthening of excitatory synapses. PMID:28642683

  11. Lack of fear response in mice (Mus musculus) exposed to human urine odor.

    PubMed

    Rivard, Germain F; Moser, Emily G; D'Ambrose, Steven P; Lin, David M

    2014-03-01

    A goal of the Guide for the Care and Use of Laboratory Animals is to improve animal welfare by minimizing sources of fear, anxiety, and stress. As a result, it includes recommendations on overcrowding, frequency of cage changes, enrichment, and group housing. However, human odorants are a potential but unexplored source of fear, anxiety, and stress. Although mice have been maintained for decades for animal research, whether mice perceive humans as predators is unknown. If so, this would necessitate changes in animal care and use procedures to minimize this source of chronic fear, anxiety, and stress. Odorants from predator urine are well known to elicit strong fear responses in mice, leading to modification of animal behavior and elevated levels of stress. To begin asking whether human odors influence mouse behavior, we tested the effect of human urine odor on fear response in mice. We assessed mouse behavior by using a modified shuttle cage to record various parameters of mouse exposure to odorants. We found that mice displayed fear responses to 2,4,5-trimethylthiazoline, a synthetic analog of red fox feces, but no fear response to DMSO, the diluent for 2,4,5-trimethylthiazoline. In contrast, mice exposed to human urine samples showed no significant fear response.

  12. Lack of Fear Response in Mice (Mus musculus) Exposed to Human Urine Odor

    PubMed Central

    Rivard, Germain F; Moser, Emily G; D'Ambrose, Steven P; Lin, David M

    2014-01-01

    A goal of the Guide for the Care and Use of Laboratory Animals is to improve animal welfare by minimizing sources of fear, anxiety, and stress. As a result, it includes recommendations on overcrowding, frequency of cage changes, enrichment, and group housing. However, human odorants are a potential but unexplored source of fear, anxiety, and stress. Although mice have been maintained for decades for animal research, whether mice perceive humans as predators is unknown. If so, this would necessitate changes in animal care and use procedures to minimize this source of chronic fear, anxiety, and stress. Odorants from predator urine are well known to elicit strong fear responses in mice, leading to modification of animal behavior and elevated levels of stress. To begin asking whether human odors influence mouse behavior, we tested the effect of human urine odor on fear response in mice. We assessed mouse behavior by using a modified shuttle cage to record various parameters of mouse exposure to odorants. We found that mice displayed fear responses to 2,4,5-trimethylthiazoline, a synthetic analog of red fox feces, but no fear response to DMSO, the diluent for 2,4,5-trimethylthiazoline. In contrast, mice exposed to human urine samples showed no significant fear response. PMID:24602539

  13. Mice lacking adenylyl cyclase type 5 (AC5) show increased ethanol consumption and reduced ethanol sensitivity.

    PubMed

    Kim, Kyoung-Shim; Kim, Hannah; Baek, In-Sun; Lee, Ko-Woon; Han, Pyung-Lim

    2011-05-01

    The adenylyl cyclase (AC)/cAMP system is believed to be a key component in regulating alcohol-drinking behavior. It was reported that adenylyl cyclase-5 (AC5) is expressed widely in the brain, with a preferential concentration in the dorsal striatum and nucleus accumbens, brain regions which are important for addiction and emotion. AC5 has been shown to be an essential mediator of morphine addiction and dopamine receptor function; however, it remains unknown whether or not AC5 plays a role in ethanol preference and sensitivity in animals. This work was carried out to determine the role of AC5 in alcohol consumption and the hypnotic response to alcohol using AC5 knockout (KO) mice. In the test for ethanol preference employing a two-bottle free-choice paradigm, AC5 KO mice showed increased ethanol consumption and preference compared with the wild-type mice. Ethanol-induced hypothermia was weakly reduced in AC5 KO mice. AC5 KO mice exhibited sedation/behavioral sleep to high-dose ethanol, but their responses were greatly suppressed compared with the wild-type mice. These results suggest that AC5 is an important signaling molecule regulating alcohol sensitivity and preference in animals. These data provide critical information for AC5 activation as a candidate target for the treatment of alcoholism.

  14. Environmental Enrichment Ameliorates Behavioral Impairments Modeling Schizophrenia in Mice Lacking Metabotropic Glutamate Receptor 5

    PubMed Central

    Burrows, Emma L; McOmish, Caitlin E; Buret, Laetitia S; Van den Buuse, Maarten; Hannan, Anthony J

    2015-01-01

    Schizophrenia arises from a complex interplay between genetic and environmental factors. Abnormalities in glutamatergic signaling have been proposed to underlie the emergence of symptoms, in light of various lines of evidence, including the psychotomimetic effects of NMDA receptor antagonists. Metabotropic glutamate receptor 5 (mGlu5) has also been implicated in the disorder, and has been shown to physically interact with NMDA receptors. To clarify the role of mGlu5-dependent behavioral expression by environmental factors, we assessed mGlu5 knockout (KO) mice after exposure to environmental enrichment (EE) or reared under standard conditions. The mGlu5 KO mice showed reduced prepulse inhibition (PPI), long-term memory deficits, and spontaneous locomotor hyperactivity, which were all attenuated by EE. Examining the cellular impact of genetic and environmental manipulation, we show that EE significantly increased pyramidal cell dendritic branching and BDNF protein levels in the hippocampus of wild-type mice; however, mGlu5 KO mice were resistant to these alterations, suggesting that mGlu5 is critical to these responses. A selective effect of EE on the behavioral response to the NMDA receptor antagonist MK-801 in mGlu5 KO mice was seen. MK-801-induced hyperlocomotion was further potentiated in enriched mGlu5 KO mice and treatment with MK-801 reinstated PPI disruption in EE mGlu5 KO mice only, a response that is absent under standard housing conditions. Together, these results demonstrate an important role for mGlu5 in environmental modulation of schizophrenia-related behavioral impairments. Furthermore, this role of the mGlu5 receptor is mediated by interaction with NMDA receptor function, which may inform development of novel therapeutics. PMID:25666312

  15. Developmental alterations in motor coordination and medium spiny neuron markers in mice lacking pgc-1α.

    PubMed

    Lucas, Elizabeth K; Dougherty, Sarah E; McMeekin, Laura J; Trinh, Alisa T; Reid, Courtney S; Cowell, Rita M

    2012-01-01

    Accumulating evidence implicates the transcriptional coactivator peroxisome proliferator activated receptor γ coactivator 1α (PGC-1α) in the pathophysiology of Huntington Disease (HD). Adult PGC-1α (-/-) mice exhibit striatal neurodegeneration, and reductions in the expression of PGC-1α have been observed in striatum and muscle of HD patients as well as in animal models of the disease. However, it is unknown whether decreased expression of PGC-1α alone is sufficient to lead to the motor phenotype and striatal pathology characteristic of HD. For the first time, we show that young PGC-1α (-/-) mice exhibit severe rotarod deficits, decreased rearing behavior, and increased occurrence of tremor in addition to the previously described hindlimb clasping. Motor impairment and striatal vacuolation are apparent in PGC-1α (-/-) mice by four weeks of age and do not improve or decline by twelve weeks of age. The behavioral and pathological phenotype of PGC-1α (-/-) mice can be completely recapitulated by conditional nervous system deletion of PGC-1α, indicating that peripheral effects are not responsible for the observed abnormalities. Evaluation of the transcriptional profile of PGC-1α (-/-) striatal neuron populations and comparison to striatal neuron profiles of R6/2 HD mice revealed that PGC-1α deficiency alone is not sufficient to cause the transcriptional changes observed in this HD mouse model. In contrast to R6/2 HD mice, PGC-1α (-/-) mice show increases in the expression of medium spiny neuron (MSN) markers with age, suggesting that the observed behavioral and structural abnormalities are not primarily due to MSN loss, the defining pathological feature of HD. These results indicate that PGC-1α is required for the proper development of motor circuitry and transcriptional homeostasis in MSNs and that developmental disruption of PGC-1α leads to long-term alterations in motor functioning.

  16. Developmental Alterations in Motor Coordination and Medium Spiny Neuron Markers in Mice Lacking PGC-1α

    PubMed Central

    Lucas, Elizabeth K.; Dougherty, Sarah E.; McMeekin, Laura J.; Trinh, Alisa T.; Reid, Courtney S.; Cowell, Rita M.

    2012-01-01

    Accumulating evidence implicates the transcriptional coactivator peroxisome proliferator activated receptor γ coactivator 1α (PGC-1α) in the pathophysiology of Huntington Disease (HD). Adult PGC-1α −/− mice exhibit striatal neurodegeneration, and reductions in the expression of PGC-1α have been observed in striatum and muscle of HD patients as well as in animal models of the disease. However, it is unknown whether decreased expression of PGC-1α alone is sufficient to lead to the motor phenotype and striatal pathology characteristic of HD. For the first time, we show that young PGC-1α −/− mice exhibit severe rotarod deficits, decreased rearing behavior, and increased occurrence of tremor in addition to the previously described hindlimb clasping. Motor impairment and striatal vacuolation are apparent in PGC-1α −/− mice by four weeks of age and do not improve or decline by twelve weeks of age. The behavioral and pathological phenotype of PGC-1α −/− mice can be completely recapitulated by conditional nervous system deletion of PGC-1α, indicating that peripheral effects are not responsible for the observed abnormalities. Evaluation of the transcriptional profile of PGC-1α −/− striatal neuron populations and comparison to striatal neuron profiles of R6/2 HD mice revealed that PGC-1α deficiency alone is not sufficient to cause the transcriptional changes observed in this HD mouse model. In contrast to R6/2 HD mice, PGC-1α −/− mice show increases in the expression of medium spiny neuron (MSN) markers with age, suggesting that the observed behavioral and structural abnormalities are not primarily due to MSN loss, the defining pathological feature of HD. These results indicate that PGC-1α is required for the proper development of motor circuitry and transcriptional homeostasis in MSNs and that developmental disruption of PGC-1α leads to long-term alterations in motor functioning. PMID:22916173

  17. Lack of TRPM2 Impaired Insulin Secretion and Glucose Metabolisms in Mice

    PubMed Central

    Uchida, Kunitoshi; Dezaki, Katsuya; Damdindorj, Boldbaatar; Inada, Hitoshi; Shiuchi, Tetsuya; Mori, Yasuo; Yada, Toshihiko; Minokoshi, Yasuhiko; Tominaga, Makoto

    2011-01-01

    OBJECTIVE TRPM2 is a Ca2+-permeable nonselective cation channel activated by adenosine dinucleotides. We previously demonstrated that TRPM2 is activated by coapplication of heat and intracellular cyclic adenosine 5′-diphosphoribose, which has been suggested to be involved in intracellular Ca2+ increase in immunocytes and pancreatic β-cells. To clarify the involvement of TRPM2 in insulin secretion, we analyzed TRPM2 knockout (TRPM2-KO) mice. RESEARCH DESIGN AND METHODS Oral and intraperitoneal glucose tolerance tests (OGTT and IPGTT) were performed in TRPM2-KO and wild-type mice. We also measured cytosolic free Ca2+ in single pancreatic cells using fura-2 microfluorometry and insulin secretion from pancreatic islets. RESULTS Basal blood glucose levels were higher in TRPM2-KO mice than in wild-type mice without any difference in plasma insulin levels. The OGTT and IPGTT demonstrated that blood glucose levels in TRPM2-KO mice were higher than those in wild-type mice, which was associated with an impairment in insulin secretion. In isolated β-cells, smaller intracellular Ca2+ increase was observed in response to high concentrations of glucose and incretin hormone in TRPM2-KO cells than in wild-type cells. Moreover, insulin secretion from the islets of TRPM2-KO mice in response to glucose and incretin hormone treatment was impaired, whereas the response to tolbutamide, an ATP-sensitive potassium channel inhibitor, was not different between the two groups. CONCLUSIONS These results indicate that TRPM2 is involved in insulin secretion stimulated by glucose and that further potentiated by incretins. Thus, TRPM2 may be a new target for diabetes therapy. PMID:20921208

  18. Colon water transport in transgenic mice lacking aquaporin-4 water channels

    PubMed Central

    WANG, KASPER S.; MA, TONGHUI; FILIZ, FERDA; VERKMAN, A. S.; BASTIDAS, J. AUGUSTO

    2012-01-01

    Transgenic null mice were used to test the hypothesis that water channel aquaporin-4 (AQP4) is involved in colon water transport and fecal dehydration. AQP4 was immunolocalized to the basolateral membrane of colonic surface epithelium of wild-type (+/+) mice and was absent in AQP4 null (−/−) mice. The transepithelial osmotic water permeability coefficient (Pf) of in vivo perfused colon of +/+ mice, measured using the volume marker 14C-labeled polyethylene glycol, was 0.016 ± 0.002 cm/s. Pf of proximal colon was greater than that of distal colon (0.020 ± 0.004 vs. 0.009 ± 0.003 cm/s, P < 0.01). Pf was significantly lower in −/− mice when measured in full-length colon (0.009 ± 0.002 cm/s, P < 0.05) and proximal colon (0.013 ± 0.002 cm/s, P < 0.05) but not in distal colon. There was no difference in water content of cecal stool from +/+ vs. −/− mice (0.80 ± 0.01 vs. 0.81 ± 0.01), but there was a slightly higher water content in defecated stool from +/+ mice (0.68 ± 0.01 vs. 0.65 ± 0.01, P < 0.05). Despite the differences in water permeability with AQP4 deletion, theophylline-induced secretion was not impaired (50 ± 9 vs. 51 ± 8 μl · min−1 · g−1). These results provide evidence that transcellular water transport through AQP4 water channels in colonic epithelium facilitates transepithelial osmotic water permeability but has little or no effect on colonic fluid secretion or fecal dehydration. PMID:10915657

  19. Post-Exposure Vaccination with MP-12 Lacking NSs Protects Mice Against Lethal Rift Valley Fever Virus Challenge

    PubMed Central

    Gowen, Brian B.; Bailey, Kevin W.; Scharton, Dionna; Vest, Zachery; Westover, Jonna B.; Skirpstunas, Ramona; Ikegami, Tetsuro

    2013-01-01

    Rift Valley fever virus (RVFV) causes severe disease in humans and livestock. There are currently no approved antivirals or vaccines for the treatment or prevention of RVF disease in humans. A major virulence factor of RVFV is the NSs protein, which inhibits host transcription including the interferon (IFN)-β gene and promotes the degradation of dsRNA-dependent protein kinase, PKR. We analyzed the efficacy of the live-attenuated MP-12 vaccine strain and MP-12 variants that lack the NSs protein as post-exposure vaccinations. Although parental MP-12 failed to elicit a protective effect in mice challenged with wild-type (wt) RVFV by the intranasal route, significant protection was demonstrated by vaccination with MP-12 strains lacking NSs when they were administered at 20 to 30 min post-exposure. Viremia and virus replication in liver, spleen and brain were also inhibited by post-exposure vaccination with MP-12 lacking NSs. The protective effect was mostly lost when vaccination was delayed 6 or 24 h after intranasal RVFV challenge. When mice were challenged subcutaneously, efficacy of MP-12 lacking NSs was diminished, most likely due to more rapid dissemination of wt RVFV. Our findings suggest that post-exposure vaccination with MP-12 lacking NSs may be developed as a novel post-exposure treatment to prevent RVF. PMID:23523764

  20. Post-exposure vaccination with MP-12 lacking NSs protects mice against lethal Rift Valley fever virus challenge.

    PubMed

    Gowen, Brian B; Bailey, Kevin W; Scharton, Dionna; Vest, Zachery; Westover, Jonna B; Skirpstunas, Ramona; Ikegami, Tetsuro

    2013-05-01

    Rift Valley fever virus (RVFV) causes severe disease in humans and livestock. There are currently no approved antivirals or vaccines for the treatment or prevention of RVF disease in humans. A major virulence factor of RVFV is the NSs protein, which inhibits host transcription including the interferon (IFN)-β gene and promotes the degradation of dsRNA-dependent protein kinase, PKR. We analyzed the efficacy of the live-attenuated MP-12 vaccine strain and MP-12 variants that lack the NSs protein as post-exposure vaccinations. Although parental MP-12 failed to elicit a protective effect in mice challenged with wild-type (wt) RVFV by the intranasal route, significant protection was demonstrated by vaccination with MP-12 strains lacking NSs when they were administered at 20-30 min post-exposure. Viremia and virus replication in liver, spleen and brain were also inhibited by post-exposure vaccination with MP-12 lacking NSs. The protective effect was mostly lost when vaccination was delayed 6 or 24 h after intranasal RVFV challenge. When mice were challenged subcutaneously, efficacy of MP-12 lacking NSs was diminished, most likely due to more rapid dissemination of wt RVFV. Our findings suggest that post-exposure vaccination with MP-12 lacking NSs may be developed as a novel post-exposure treatment to prevent RVF.

  1. Increased morphine analgesia and reduced side effects in mice lacking the tac1 gene

    PubMed Central

    Bilkei-Gorzo, A; Berner, J; Zimmermann, J; Wickström, R; Racz, I; Zimmer, A

    2010-01-01

    Background and purpose: Although morphine is a very effective analgesic, its narrow therapeutic index and severe side effects limit its therapeutic use. Previous studies indicated that the pharmacological responses of opioids are modulated by genetic and pharmacological invalidation of tachykinin receptors. Here we address the role of substance P and neurokinin A, which are both encoded by the tachykinin 1 (tac1) gene, as modulators of opioid effects. Experimental approach: The analgesic and side effect potential of morphine was compared between wild-type and tac1 null mutant mice. Key results: Morphine was a more potent analgesic in tac1 null mutant mice, that is, in the absence of substance P/neurokinin A signalling. Interestingly, the most serious side effect of acute morphine, that is respiratory depression, was reduced in tac1−/− animals. Comparing the addictive potential of morphine in wild-type and knockout animals we found that morphine preference was similar between the genotypes. However, the aversive effect of withdrawal precipitated by naloxone in morphine-dependent animals was significantly reduced in tac1 knockout mice. Behavioural sensitization, the underlying mechanism of addiction, was also significantly lower in tac1−/− mice. Conclusion and implications: The analgesic potential of morphine was increased in tac1 knockout mice. In contrast, both the ventilatory suppressing effect and the addictive potential of morphine were reduced. These results suggest that reducing activity of the tachykinin system may be a possible strategy to improve the pharmacological potential of morphine. PMID:20590634

  2. Lack of fibulin-3 causes early aging and herniation, but not macular degeneration in mice.

    PubMed

    McLaughlin, Precious J; Bakall, Benjamin; Choi, Jiwon; Liu, Zhonglin; Sasaki, Takako; Davis, Elaine C; Marmorstein, Alan D; Marmorstein, Lihua Y

    2007-12-15

    A mutation in the EFEMP1 gene causes Malattia Leventinese, an inherited macular degenerative disease with strong similarities to age-related macular degeneration. EFEMP1 encodes fibulin-3, an extracellular matrix protein of unknown function. To investigate its biological role, the murine Efemp1 gene was inactivated through targeted disruption. Efemp1(-/-) mice exhibited reduced reproductivity, and displayed an early onset of aging-associated phenotypes including reduced lifespan, decreased body mass, lordokyphosis, reduced hair growth, and generalized fat, muscle and organ atrophy. However, these mice appeared to have normal wound healing ability. Efemp1(-/-) mice on a C57BL/6 genetic background developed multiple large hernias including inguinal hernias, pelvic prolapse and protrusions of the xiphoid process. In contrast, Efemp1(-/-) mice on a BALB/c background rarely had any forms of hernias, indicating the presence of modifiers for fibulin-3's function in different mouse strains. Histological analysis revealed a marked reduction of elastic fibers in fascia, a thin layer of connective tissue maintaining and protecting structures throughout the body. No apparent macular degeneration associated defects were found in Efemp1(-/-) mice, suggesting that loss of fibulin-3 function is not the mechanism by which the mutation in EFEMP1 causes macular degeneration. These data demonstrate that fibulin-3 plays an important role in maintaining the integrity of fascia connective tissues and regulates aging.

  3. Mice lacking MKP-1 and MKP-5 Reveal Hierarchical Regulation of Regenerative Myogenesis.

    PubMed

    Shi, Hao; Gatzke, Florian; Molle, Julia M; Lee, Han Bin; Helm, Emma T; Oldham, Jessie J; Zhang, Lei; Gerrard, David E; Bennett, Anton M

    2015-11-12

    The relative contribution of the MAP kinase phosphatases (MKPs) in the integration of MAP kinase-dependent signaling during regenerative myogenesis has yet to be fully investigated. MKP-1 and MKP-5 maintain skeletal muscle homeostasis by providing positive and negative effects on regenerative myogenesis, respectively. In order to define the hierarchical contributions of MKP-1 and MKP-5 in the regulation of regenerative myogenesis we genetically ablated both MKPs in mice. MKP-1/MKP 5-deficient double-knockout (MKP1/5- DKO) mice were viable, and upon skeletal muscle injury, were severely impaired in their capacity to regenerate skeletal muscle. Satellite cells were fewer in number in MKP1/5-DKO mice and displayed a reduced proliferative capacity as compared with those derived from wild-type mice. MKP1/5-DKO mice exhibited increased inflammation and the macrophage M1 to M2 transition during the resolution of inflammation was impaired following injury. These results demonstrate that the actions of MKP-1 to positively regulate myogenesis predominate over those of MKP-5, which negatively regulates myogenesis. Hence, MKP-1 and MKP-5 function to maintain skeletal muscle homeostasis through non-overlapping and opposing signaling pathways.

  4. Lack of evidence for neonatal misoprostol neurodevelopmental toxicity in C57BL6/J mice.

    PubMed

    Koenig, Claire M; Walker, Cheryl K; Qi, Lihong; Pessah, Isaac N; Berman, Robert F

    2012-01-01

    Misoprostol is a synthetic analogue of prostaglandin E1 that is administered to women at high doses to induce uterine contractions for early pregnancy termination and at low doses to aid in cervical priming during labor. Because of the known teratogenic effects of misoprostol when given during gestation and its effects on axonal growth in vitro, we examined misoprostol for its potential as a neurodevelopmental toxicant when administered to neonatal C57BL6/J mice. Mice were injected subcutaneously (s.c.) with 0.4, 4 or 40 µg/kg misoprostol on postnatal day 7, the approximate developmental stage in mice of human birth, after which neonatal somatic growth, and sensory and motor system development were assessed. These doses were selected to span the range of human exposure used to induce labor. In addition, adult mice underwent a battery of behavioral tests relevant to neurodevelopmental disorders such as autism including tests for anxiety, stereotyped behaviors, social communication and interactions, and learning and memory. No significant effects of exposure were found for any measure of development or behavioral endpoints. In conclusion, the results of the present study in C57BL/6J mice do not provide support for neurodevelopmental toxicity after misoprostol administration approximating human doses and timed to coincide with the developmental stage of human birth.

  5. Diversity of TCRs on natural Foxp3+ T cells in mice lacking Aire expression.

    PubMed

    Daniely, Danielle; Kern, Joanna; Cebula, Anna; Ignatowicz, Leszek

    2010-06-15

    Medullary thymic epithelial cells expressing the Aire gene play a critical role in the induction of tolerance to tissue-specific Ags (TSAs). It was postulated that recognition of Aire-controlled TSAs by immature thymocytes results in the selection of natural CD4+Foxp3+ regulatory T cells (Tregs) and enriches this repertoire in self-reactive receptors, contributing to its vast diversity. In this study, we compared the TCRs on individual Tregs in Aire+ and Aire- mice expressing a miniature TCR repertoire (TCRmini) along with GFP driven by the Foxp3 promoter (Foxp3GFP). The Treg TCR repertoires in Aire+ and Aire- TCRminiFoxp3GFP mice were similar and more diverse than their repertoires on CD4+ Foxp3- thymocytes. Further, TCRs found on potentially self-reactive T cells, with an activated phenotype (CD4+Foxp3-CD62Llow) in Aire- TCRminiFoxp3GFP mice, appear distinct from TCRs found on Tregs in Aire+ TCRminiFoxp3GFP mice. Lastly, we found no evidence that TSAs presented by medullary thymic epithelial cells in Aire+TCRmini mice are often recognized as agonists by Treg-derived TCR hybridomas or CD4+CD25+ thymocytes, containing both natural Tregs and precursors. Thus, positive selection and self-reactivity of the global Treg repertoire are not controlled by Aire-dependent TSAs.

  6. Diversity of TCRs on Natural Foxp3+ T Cells in Mice Lacking Aire Expression

    PubMed Central

    Daniely, Danielle; Kern, Joanna; Cebula, Anna; Ignatowicz, Leszek

    2011-01-01

    Medullary thymic epithelial cells expressing the Aire gene play a critical role in the induction of tolerance to tissue-specific Ags (TSAs). It was postulated that recognition of Aire-controlled TSAs by immature thymocytes results in the selection of natural CD4+Foxp3+ regulatory T cells (Tregs) and enriches this repertoire in self-reactive receptors, contributing to its vast diversity. In this study, we compared the TCRs on individual Tregs in Aire+ and Aire− mice expressing a miniature TCR repertoire (TCRmini) along with GFP driven by the Foxp3 promoter (Foxp3GFP). The Treg TCR repertoires in Aire+ and Aire− TCRminiFoxp3GFP mice were similar and more diverse than their repertoires on CD4+ Foxp3− thymocytes. Further, TCRs found on potentially self-reactive T cells, with an activated phenotype (CD4+Foxp3−CD62Llow) in Aire− TCRminiFoxp3GFP mice, appear distinct from TCRs found on Tregs in Aire+ TCRminiFoxp3GFP mice. Lastly, we found no evidence that TSAs presented by medullary thymic epithelial cells in Aire+TCRmini mice are often recognized as agonists by Treg-derived TCR hybridomas or CD4+CD25+ thymocytes, containing both natural Tregs and precursors. Thus, positive selection and self-reactivity of the global Treg repertoire are not controlled by Aire-dependent TSAs. PMID:20483761

  7. Nitric oxide-dependent penile erection in mice lacking neuronal nitric oxide synthase.

    PubMed Central

    Burnett, A. L.; Nelson, R. J.; Calvin, D. C.; Liu, J. X.; Demas, G. E.; Klein, S. L.; Kriegsfeld, L. J.; Dawson, V. L.; Dawson, T. M.; Snyder, S. H.

    1996-01-01

    BACKGROUND: Nitric oxide (NO) has been implicated as a mediator of penile erection, because the neuronal isoform of NO synthase (NOS) is localized to the penile innervation and NOS inhibitors selectively block erections. NO can also be formed by two other NOS isoforms derived from distinct genes, inducible NOS (iNOS) and endothelial NOS (eNOS). To clarify the source of NO in penile function, we have examined mice with targeted deletion of the nNOS gene (nNOS- mice). MATERIALS AND METHODS: Mating behavior, electrophysiologically induced penile erection, isolated erectile tissue isometric tension, and eNOS localization by immunohistochemistry and Western blot were performed on nNOS- mice and wild-type controls. RESULTS: Both intact animal penile erections and isolated erectile tissue function are maintained in nNOS mice, in agreement with demonstrated normal sexual behaviors, but is stereospecifically blocked by the NOS inhibitor, L-nitroarginine methyl ester (L-NAME). eNOS is abundantly present in endothelium of penile vasculature and sinusoidal endothelium within the corpora cavemosa, with levels that are significantly higher in nNOS- mice than in wild-type controls. CONCLUSIONS: eNOS mediates NO-dependent penile erection in nNOS- animals and normal penile erection. These data clarify the role of nitric oxide in penile erection and may have implications for therapeutic agents with selective effects on NOS isoforms. Images FIG. 2 FIG. 3 FIG. 5 PMID:8784782

  8. Nitric oxide-dependent penile erection in mice lacking neuronal nitric oxide synthase.

    PubMed

    Burnett, A L; Nelson, R J; Calvin, D C; Liu, J X; Demas, G E; Klein, S L; Kriegsfeld, L J; Dawson, V L; Dawson, T M; Snyder, S H

    1996-05-01

    Nitric oxide (NO) has been implicated as a mediator of penile erection, because the neuronal isoform of NO synthase (NOS) is localized to the penile innervation and NOS inhibitors selectively block erections. NO can also be formed by two other NOS isoforms derived from distinct genes, inducible NOS (iNOS) and endothelial NOS (eNOS). To clarify the source of NO in penile function, we have examined mice with targeted deletion of the nNOS gene (nNOS- mice). Mating behavior, electrophysiologically induced penile erection, isolated erectile tissue isometric tension, and eNOS localization by immunohistochemistry and Western blot were performed on nNOS- mice and wild-type controls. Both intact animal penile erections and isolated erectile tissue function are maintained in nNOS mice, in agreement with demonstrated normal sexual behaviors, but is stereospecifically blocked by the NOS inhibitor, L-nitroarginine methyl ester (L-NAME). eNOS is abundantly present in endothelium of penile vasculature and sinusoidal endothelium within the corpora cavemosa, with levels that are significantly higher in nNOS- mice than in wild-type controls. eNOS mediates NO-dependent penile erection in nNOS- animals and normal penile erection. These data clarify the role of nitric oxide in penile erection and may have implications for therapeutic agents with selective effects on NOS isoforms.

  9. Mice Lacking Platelet-Derived Growth Factor D Display a Mild Vascular Phenotype

    PubMed Central

    Muhl, Lars; Ehnman, Monika; Tannenberg, Philip; Lawrence, Anna-Lisa; Betsholtz, Christer; Eriksson, Ulf

    2016-01-01

    Platelet-derived growth factor D (PDGF-D) is the most recently discovered member of the PDGF family. PDGF-D signals through PDGF receptor β, but its biological role remains largely unknown. In contrast to other members of the PDGF family of growth factors, which have been extensively investigated using different knockout approaches in mice, PDGF-D has until now not been characterized by gene inactivation in mice. Here, we present the phenotype of a constitutive Pdgfd knockout mouse model (Pdgfd-/-), carrying a LacZ reporter used to visualize Pdgfd promoter activity. Inactivation of the Pdgfd gene resulted in a mild phenotype in C57BL/6 mice, and the offspring was viable, fertile and generally in good health. We show that Pdgfd reporter gene activity was consistently localized to vascular structures in both postnatal and adult tissues. The expression was predominantly arterial, often localizing to vascular bifurcations. Endothelial cells appeared to be the dominating source for Pdgfd, but reporter gene activity was occasionally also found in subpopulations of mural cells. Tissue-specific analyses of vascular structures revealed that NG2-expressing pericytes of the cardiac vasculature were disorganized in Pdgfd-/- mice. Furthermore, Pdgfd-/- mice also had a slightly elevated blood pressure. In summary, the vascular expression pattern together with morphological changes in NG2-expressing cells, and the increase in blood pressure, support a function for PDGF-D in regulating systemic arterial blood pressure, and suggests a role in maintaining vascular homeostasis. PMID:27032083

  10. Augmentation of methamphetamine-induced behaviors in transgenic mice lacking the trace amine-associated receptor 1

    PubMed Central

    Achat-Mendes, Cindy; Lynch, Laurie J.; Sullivan, Katherine A.; Vallender, Eric J.; Miller, Gregory M.

    2011-01-01

    The trace amine-associated receptor 1 (TAAR1) is a G protein-coupled receptor that is functionally activated by amphetamine-based psychostimulants, including amphetamine, methamphetamine and MDMA. Previous studies have shown that in transgenic mice lacking the TAAR1 gene (TAAR1 knockout; KO) a single injection of amphetamine can produce enhanced behavioral responses compared to responses evoked in wild-type (WT) mice. Further, the psychostimulant effects of cocaine can be diminished by selective activation of TAAR1. These findings suggest that TAAR1 might be implicated in the rewarding properties of psychostimulants. To investigate the role of TAAR1 in the rewarding effects of drugs of abuse, the psychomotor stimulating effects of amphetamine and methamphetamine and the conditioned rewarding effects of methamphetamine and morphine were compared between WT and TAAR1 KO mice. In locomotor activity studies, both single and repeated exposure to d-amphetamine or methamphetamine generated significantly higher levels of total distance travelled in TAAR1 KO mice compared to WT mice. In conditioned place preference (CPP) studies, TAAR1 KO mice acquired methamphetamine-induced CPP earlier than WT mice and retained CPP longer during extinction training. In orphine-induced CPP, both WT and KO genotypes displayed similar levels of CPP. Results from locomotor activity studies suggest that TAAR1 may have a modulatory role in the behavioral sensitization to amphetamine-based psychostimulants. That methamphetamine- but not morphine-induced CPP was augmented in TAAR1 KO mice suggests a selective role of TAAR1 in the conditioned reinforcing effects of methamphetamine. Collectively, these findings provide support for a regulatory role of TAAR1 in methamphetamine signaling. PMID:22079347

  11. Lack of endogenous IL-10 enhances production of proinflammatory cytokines and leads to Brucella abortus clearance in mice.

    PubMed

    Corsetti, Patrícia P; de Almeida, Leonardo A; Carvalho, Natália B; Azevedo, Vasco; Silva, Teane M A; Teixeira, Henrique C; Faria, Ana C; Oliveira, Sergio C

    2013-01-01

    IL-10 is a cytokine that regulates the balance between pathogen clearance and immunopathology. Brucella abortus is an intracellular bacterium that causes chronic disease in humans and domestic animals. Here we evaluated the contribution of IL-10 in host immune response and pathology during B. abortus infection. To assess the role of IL-10 in vivo, IL-10 knockout (KO) or 129 Sv/Ev (wild-type) mice were infected with B. abortus and the number of viable bacteria from the spleen was determined at 1, 2, 3, 6 and 14-weeks postinfection. IL-10 KO mice showed reduced bacterial loads in the spleen when compared to wild-type mice during all time points studied. Additionally, at 14-weeks postinfection IL-10 KO mice had totally cleared the infection. This clearance was preceded by an enhanced IFN-γ, TNF-α and IL-17 responses in both the serum and the spleen of IL-10 KO mice. Additionally, dendritic cells from infected IL-10 KO mice produced elevated levels of IL-12 and TNF-α compared to wild-type animals. Histopathology analysis was performed and both KO and wild-type mice developed multifocal granulomas and necrosis in the liver. However, at six-weeks postinfection reduced numbers of granulomas was detected in IL-10 KO mice compared to wild-type animals. This reduced liver pathology at later stage of infection was accompanied by increased numbers of CD4+CD25+foxp3+ T cells and expression of TGF-β in IL-10 KO splenocytes. Taken together, our findings demonstrate that IL-10 modulates the proinflammatory immune response to B. abortus infection and the lack of IL-10 increases resistance to Brucella infection.

  12. Mice lacking the synaptic adhesion molecule Neph2/Kirrel3 display moderate hyperactivity and defective novel object preference

    PubMed Central

    Choi, Su-Yeon; Han, Kihoon; Cutforth, Tyler; Chung, Woosuk; Park, Haram; Lee, Dongsoo; Kim, Ryunhee; Kim, Myeong-Heui; Choi, Yeeun; Shen, Kang; Kim, Eunjoon

    2015-01-01

    Synaptic adhesion molecules regulate diverse aspects of neuronal synapse development, including synapse specificity, formation, and maturation. Neph2, also known as Kirrel3, is an immunoglobulin superfamily adhesion molecule implicated in intellectual disability, neurocognitive delay associated with Jacobsen syndrome, and autism spectrum disorders. We here report mice lacking Neph2 (Neph2-/- mice) display moderate hyperactivity in a familiar, but not novel, environment and defective novel object recognition with normal performances in Morris water maze spatial learning and memory, contextual fear conditioning and extinction, and pattern separation tests. These mice also show normal levels of anxiety-like behaviors, social interaction, and repetitive behaviors. At the synapse level, Neph2-/- dentate gyrus granule cells exhibit unaltered dendritic spine density and spontaneous excitatory synaptic transmission. These results suggest that Neph2 is important for normal locomotor activity and object recognition memory. PMID:26283919

  13. Atypical scrapie prions from sheep and lack of disease in transgenic mice overexpressing human prion protein.

    PubMed

    Wadsworth, Jonathan D F; Joiner, Susan; Linehan, Jacqueline M; Balkema-Buschmann, Anne; Spiropoulos, John; Simmons, Marion M; Griffiths, Peter C; Groschup, Martin H; Hope, James; Brandner, Sebastian; Asante, Emmanuel A; Collinge, John

    2013-11-01

    Public and animal health controls to limit human exposure to animal prions are focused on bovine spongiform encephalopathy (BSE), but other prion strains in ruminants may also have zoonotic potential. One example is atypical/Nor98 scrapie, which evaded statutory diagnostic methods worldwide until the early 2000s. To investigate whether sheep infected with scrapie prions could be another source of infection, we inoculated transgenic mice that overexpressed human prion protein with brain tissue from sheep with natural field cases of classical and atypical scrapie, sheep with experimental BSE, and cattle with BSE. We found that these mice were susceptible to BSE prions, but disease did not develop after prolonged postinoculation periods when mice were inoculated with classical or atypical scrapie prions. These data are consistent with the conclusion that prion disease is less likely to develop in humans after exposure to naturally occurring prions of sheep than after exposure to epizootic BSE prions of ruminants.

  14. Tail-suspended mice lacking calponin H1 experience decreased bone loss.

    PubMed

    Yotsumoto, Naoki; Takeoka, Michiko; Yokoyama, Minesuke

    2010-07-01

    Calponin h1 (CNh1) is an actin-binding protein originally isolated from vascular smooth muscle and has been reported to suppress bone formation. We are therefore curious how CNh1 is involved in bone loss that is caused by space flight in microgravity. We assessed the effects of tail suspension (TS) in C57BL/6J wild (CN+/+) and CNh1-deleted (CN-/-) mice to elucidate the role of CNh1 in bone loss under weightless conditions. Bone mineral density (BMD) of tibiae was measured by single energy X-ray absorptiometry, and bone volume fraction (BV/TV), mineral apposition rate (MAR), and bone formation rate (BFR/BS) were measured by bone histomorphometry. BMD, BV/TV, MAR, and BFR/BS were lower in CN+/+ mice with TS than in those without. In the CN-/- group, however, the decrease in each of these parameters by TS was ameliorated. Decreases in serum osteocalcin levels by TS in CN+/+ mice were attenuated in CN-/- mice. Furthermore, urinary deoxypyridinolin (DPD), an indicator of bone resorption, was increased in CN+/+ mice following TS, but not in CN-/- mice. In transfection experiments, the degree of induction of bone formation markers, alkaline phosphatase (ALP) activity and bone morphogenetic protein (BMP)-4 mRNA expression, under stimulation with BMP-2, was lower in MC3T3-E1 mouse osteoblast-like cells expressing CNh1 than that in mock transfected cells. Notably, the BMP-2-induced ALP activity was decreased by CNh1 expression, which was partially rescued by treatment with the Rho kinase inhibitor Y27632. Taken together, these results indicate that CNh1 is responsible for weightlessness-induced bone loss in part through Rho signaling pathway.

  15. Contextual fear conditioning is enhanced in mice lacking functional sphingosine kinase 2.

    PubMed

    Lei, Mona; Shafique, Adeena; Shang, Kani; Couttas, Timothy A; Zhao, Hua; Don, Anthony S; Karl, Tim

    2017-08-30

    The lipid sphingosine 1-phosphate (S1P) is a potent neuroprotective signalling molecule that signals through its own family of five G-protein coupled receptors. S1P signalling enhances presynaptic glutamate release and is essential for neural development. S1P is synthesized by the enzymes sphingosine kinases 1 and 2 (SPHK1 and SPHK2), of which SPHK2 mRNA and activity is more abundant in the brain. In this study we investigated the consequences of global SphK2 knockout (SphK2(-/-)) on basic motor capabilities, anxiety, learning, and memory in mice, using a range of tests including the elevated plus maze, the cheeseboard, contextual and cued fear conditioning, and fear extinction. Loss of SphK2 resulted in an 85-90% reduction in brain S1P levels, and was associated with a notably higher freezing response in a novel context. SphK2 knockout mice also exhibited increased contextual fear conditioning but the extinction of contextual fear memory was similar to control mice. SphK2(-/-) mice, contrary to their control littermates, did not respond to cue presentation with increased freezing. Anxiety measures in the elevated plus maze were not different between SphK2(-/-) mice and control littermates. Also, knockout mice showed no deficits in neurological reflexes or motor functions, and performed as well as their control littermates in the spatial memory test. Our findings demonstrate that SphK2 is responsible for the vast majority of S1P synthesis in the mouse brain, and plays a role in freezing responses as evaluated in the fear conditioning paradigm. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Developmental vascular remodeling defects and postnatal kidney failure in mice lacking Gpr116 (Adgrf5) and Eltd1 (Adgrl4)

    PubMed Central

    Wietelmann, Astrid; Kojonazarov, Baktybek; Atzberger, Ann; Tang, Cong; Schermuly, Ralph Theo; Gröne, Hermann-Josef; Offermanns, Stefan

    2017-01-01

    GPR116 (ADGRF5) and ELTD1 (ADGRL4) belong to different subfamilies of the adhesion G-protein-coupled receptor group but are both expressed in endothelial cells. We therefore analyzed their functions in mice lacking these receptors. While loss of GPR116 or ELTD1 alone had no obvious effect on cardiovascular or kidney function, mice lacking both, GPR116 and ELTD1, showed malformations of the aortic arch arteries and the cardiac outflow tract leading to perinatal lethality in about 50% of the mutants. In addition to cardiovascular malformations, surviving mice developed renal thrombotic microangiopathy as well as hemolysis and splenomegaly, and their lifespan was significantly reduced. Loss of GPR116 and ELTD1 specifically in endothelial cells or neural crest-derived cells did not recapitulate any of the phenotypes observed in GPR116-ELTD1 double deficient mice, indicating that loss of GPR116 and ELTD1 expressed by other cells accounts for the observed cardiovascular and renal defects. PMID:28806758

  17. Sevoflurane anesthesia alters exploratory and anxiety-like behavior in mice lacking the beta2 nicotinic acetylcholine receptor subunit.

    PubMed

    Wiklund, Andreas; Granon, Sylvie; Cloëz-Tayarani, Isabelle; Faure, Philippe; le Sourd, Anne-Marie; Sundman, Eva; Changeux, Jean-Pierre; Eriksson, Lars I

    2008-11-01

    Preexisting cognitive impairment and advanced age are factors that increase the risk of developing postoperative cognitive dysfunction. Because anesthetic agents interfere with cholinergic transmission and as impairment of cholinergic function is associated with cognitive decline, the authors studied how the volatile anesthetic sevoflurane affects exploratory and anxiety-like behavior in young and aged animals with a genetically modified cholinergic system. Young and aged wild-type and mutant mice lacking the beta2 subunit of the nicotinic cholinergic receptor (beta2KO) were anesthetized for 2 h with 2.6% sevoflurane in oxygen and compared with nonanesthetized controls. Locomotor activity and organization of movement in the open field model were assessed before and 24 h after anesthesia. Locomotor activity and anxiety-like behavior in the elevated plus maze were assessed 24 h after anesthesia. High- and low-affinity nicotinic receptor and cholinergic uptake site densities were evaluated in the hippocampus, amygdala, and forebrain regions using receptor autoradiography. Sevoflurane anesthesia significantly reduced locomotor activity, altered temporospatial organization of trajectories, and increased anxiety-like behavior in young beta2KO mice, whereas no such changes were observed in young wild-type mice. Aged wild-type and beta2KO mice displayed reactions that were similar, but not identical, to the reactions of young mice to sevoflurane anesthesia. However, behavioral changes were not associated with differences in nicotinic receptor or cholinergic uptake site densities. In conclusion, sevoflurane anesthesia altered exploratory and anxiety-like behavior in mice lacking the beta2 nicotinic acetylcholine receptor subunit.

  18. Hypothalamic plasticity of neuropeptide Y is lacking in brain-type creatine kinase double knockout mice with defective thermoregulation.

    PubMed

    Van der Zee, Catharina E E M

    2013-11-05

    The neural substrate of adaptive thermoregulation in mice lacking both brain-type creatine kinase isoforms is further investigated. The cytosolic brain-type creatine kinase (CK-B) and mitochondrial ubiquitous creatine kinase (UbCKmit) are expressed in neural cells throughout the central and peripheral nervous system, where they have an important role in cellular energy homeostasis. Several integral functions appear altered when creatine kinases are absent in the brain (Jost et al., 2002; Streijger et al., 2004, 2005), which has been explained by inefficient neuronal transmission. The CK--/-- double knockout mice demonstrate every morning a body temperature drop of ~1.0 °C, and they have impaired thermogenesis, as revealed by severe hypothermia upon cold exposure. This defective thermoregulation is not associated with abnormal food intake, decreased locomotive activity, or increased torpor sensitivity. Although white and brown adipose tissue fat pads are diminished in CK--/-- mice, intravenous norepinephrine infusion results in a normal brown adipose tissue response with increasing core body temperatures, indicating that the sympathetic innervation functions correctly (Streijger et al., 2009). This study revealed c-fos changes following a cold challenge, and that neuropeptide Y levels were decreased in the paraventricular nucleus of wildtype, but not CK--/--, mice. A reduction in hypothalamic neuropeptide Y is coupled to increased uncoupling protein 1 expression in brown adipose tissue, resulting in thermogenesis. In CK--/-- mice the neuropeptide Y levels did not change. This lack of hypothalamic plasticity of neuropeptide Y might be the result of inefficient neuronal transmission or can be explained by the previous observation of reduced circulating levels of leptin in CK--/-- mice.

  19. Mammary ductal growth is impaired in mice lacking leptin-dependent signal transducer and activator of transcription 3 signaling.

    PubMed

    Thorn, Stephanie R; Giesy, Sarah L; Myers, Martin G; Boisclair, Yves R

    2010-08-01

    Mice lacking leptin (ob/ob) or its full-length receptor (db/db) are obese and reproductively incompetent. Fertility, pregnancy, and lactation are restored, respectively, in ob/ob mice treated with leptin through mating, d 6.5 post coitum, and pregnancy. Therefore, leptin signaling is needed for lactation, but the timing of its action and the affected mammary process remain unknown. To address this issue, we used s/s mice lacking only leptin-dependent signal transducer and activator of transcription (STAT)3 signaling. These mice share many features with db/db mice, including obesity, but differ by retaining sufficient activity of the hypothalamic-pituitary-ovarian axis to support reproduction. The s/s mammary epithelium was normal at 3 wk of age but failed to expand through the mammary fat pad (MFP) during the subsequent pubertal period. Ductal growth failure was not corrected by estrogen therapy and did not relate to inadequate IGF-I production by the MFP or to the need for epithelial or stromal leptin-STAT3 signaling. Ductal growth failure coincided with adipocyte hypertrophy and increased MFP production of leptin, TNFalpha, and IL6. These cytokines, however, were unable to inhibit the proliferation of a collection of mouse mammary epithelial cell lines. In conclusion, the very first step of postnatal mammary development fails in s/s mice despite sufficient estrogen IGF-I and an hypothalamic-pituitary-ovarian axis capable of supporting reproduction. This failure is not caused by mammary loss of leptin-dependent STAT3 signaling or by the development of inflammation. These data imply the existence of an unknown mechanism whereby leptin-dependent STAT3 signaling and obesity alter mammary ductal development.

  20. Increased susceptibility to amyloid-β-induced neurotoxicity in mice lacking the low-density lipoprotein receptor.

    PubMed

    de Oliveira, Jade; Moreira, Eduardo Luiz Gasnhar; dos Santos, Danúbia Bonfanti; Piermartiri, Tetsadê Camboim; Dutra, Rafael Cypriano; Pinton, Simone; Tasca, Carla Inês; Farina, Marcelo; Prediger, Rui Daniel Schröder; de Bem, Andreza Fabro

    2014-01-01

    Familial hypercholesterolemia is caused by inherited genetic abnormalities that directly or indirectly affect the function of the low-density lipoprotein (LDL) receptor. This condition is characterized by defective catabolism of LDL which results in increased plasma cholesterol concentrations and premature coronary artery disease. Nevertheless, there is increasing preclinical and clinical evidence indicating that familial hypercholesterolemia subjects show a particularly high incidence of mild cognitive impairment. Moreover, the LDL receptor (LDLr) has been implicated as the main central nervous system apolipoprotein E receptor that regulates amyloid deposition in distinct mouse models of β-amyloidosis. In this regard, herein we hypothesized that the lack of LDLr would enhance the susceptibility to amyloid-β-(Aβ)-induced neurotoxicity in mice. Using the acute intracerebroventricular injection of aggregated Aβ(1-40) peptide (400 pmol/mouse), a useful approach for the investigation of molecular mechanisms involved in Aβ toxicity, we observed oxidative stress, neuroinflammation, and neuronal membrane damage within the hippocampus of C57BL/6 wild-type mice, which were associated with spatial reference memory and working memory impairments. In addition, our data show that LDLr knockout (LDLr(-/-)) mice, regardless of Aβ treatment, displayed memory deficits and increased blood-brain barrier permeability. Nonetheless, LDLr(-/-) mice treated with Aβ(1-40) peptide presented increased acetylcholinesterase activity, astrogliosis, oxidative imbalance, and cell permeability within the hippocampus in comparison with Aβ(1-40)-treated C57BL/6 wild-type mice. Overall, the present study shows that the lack of LDLr increases the susceptibility to Aβ-induced neurotoxicity in mice providing new evidence about the crosslink between familial hypercholesterolemia and cognitive impairment.

  1. Failure of fluid absorption in the endolymphatic sac initiates cochlear enlargement that leads to deafness in mice lacking pendrin expression.

    PubMed

    Kim, Hyoung-Mi; Wangemann, Philine

    2010-11-17

    Mutations of SLC26A4 are among the most prevalent causes of hereditary deafness. Deafness in the corresponding mouse model, Slc26a4(-/-), results from an abnormally enlarged cochlear lumen. The goal of this study was to determine whether the cochlear enlargement originates with defective cochlear fluid transport or with a malfunction of fluid transport in the connected compartments, which are the vestibular labyrinth and the endolymphatic sac. Embryonic inner ears from Slc26a4(+/-) and Slc26a4(-/-) mice were examined by confocal microscopy ex vivo or after 2 days of organ culture. Culture allowed observations of intact, ligated or partially resected inner ears. Cochlear lumen formation was found to begin at the base of the cochlea between embryonic day (E) 13.5 and 14.5. Enlargement was immediately evident in Slc26a4(-/-) compared to Slc26a4(+/-) mice. In Slc26a4(+/-) and Slc26a4(-/-) mice, separation of the cochlea from the vestibular labyrinth by ligation at E14.5 resulted in a reduced cochlear lumen. Resection of the endolymphatic sacs at E14.5 led to an enlarged cochlear lumen in Slc26a4(+/-) mice but caused no further enlargement of the already enlarged cochlear lumen in Slc26a4(-/-) mice. Ligation or resection performed later, at E17.5, did not alter the cochlea lumen. In conclusion, the data suggest that cochlear lumen formation is initiated by fluid secretion in the vestibular labyrinth and temporarily controlled by fluid absorption in the endolymphatic sac. Failure of fluid absorption in the endolymphatic sac due to lack of Slc26a4 expression appears to initiate cochlear enlargement in mice, and possibly humans, lacking functional Slc26a4 expression.

  2. Attenuated traumatic axonal injury and improved functional outcome after traumatic brain injury in mice lacking Sarm1.

    PubMed

    Henninger, Nils; Bouley, James; Sikoglu, Elif M; An, Jiyan; Moore, Constance M; King, Jean A; Bowser, Robert; Freeman, Marc R; Brown, Robert H

    2016-04-01

    Axonal degeneration is a critical, early event in many acute and chronic neurological disorders. It has been consistently observed after traumatic brain injury, but whether axon degeneration is a driver of traumatic brain injury remains unclear. Molecular pathways underlying the pathology of traumatic brain injury have not been defined, and there is no efficacious treatment for traumatic brain injury. Here we show that mice lacking the mouse Toll receptor adaptor Sarm1 (sterile α/Armadillo/Toll-Interleukin receptor homology domain protein) gene, a key mediator of Wallerian degeneration, demonstrate multiple improved traumatic brain injury-associated phenotypes after injury in a closed-head mild traumatic brain injury model. Sarm1(-/-) mice developed fewer β-amyloid precursor protein aggregates in axons of the corpus callosum after traumatic brain injury as compared to Sarm1(+/+) mice. Furthermore, mice lacking Sarm1 had reduced plasma concentrations of the phophorylated axonal neurofilament subunit H, indicating that axonal integrity is maintained after traumatic brain injury. Strikingly, whereas wild-type mice exibited a number of behavioural deficits after traumatic brain injury, we observed a strong, early preservation of neurological function in Sarm1(-/-) animals. Finally, using in vivo proton magnetic resonance spectroscopy we found tissue signatures consistent with substantially preserved neuronal energy metabolism in Sarm1(-/-) mice compared to controls immediately following traumatic brain injury. Our results indicate that the SARM1-mediated prodegenerative pathway promotes pathogenesis in traumatic brain injury and suggest that anti-SARM1 therapeutics are a viable approach for preserving neurological function after traumatic brain injury. © The Author (2016). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. The Role of AhR in Breast Cancer Development

    DTIC Science & Technology

    2006-07-01

    other cell types, galangin is a potent inhibitor of the aryl hydrocarbon receptor (AhR), an environmental carcinogen-responsive transcription factor...constitutively active AhR. Constitutive and environmental chemical-inducible AhR activity was profoundly suppressed by galangin as was cell growth...However, the failure of a-naphthoflavone or FhAhRR transfection to block growth indicated that galangin -mediated AhR inhibition was either insufficient

  4. Abnormal thyroid hormone metabolism in mice lacking the monocarboxylate transporter 8.

    PubMed

    Trajkovic, Marija; Visser, Theo J; Mittag, Jens; Horn, Sigrun; Lukas, Jan; Darras, Veerle M; Raivich, Genadij; Bauer, Karl; Heuer, Heike

    2007-03-01

    In humans, inactivating mutations in the gene of the thyroid hormone transporter monocarboxylate transporter 8 (MCT8; SLC16A2) lead to severe forms of psychomotor retardation combined with imbalanced thyroid hormone serum levels. The MCT8-null mice described here, however, developed without overt deficits but also exhibited distorted 3,5,3'-triiodothyronine (T3) and thyroxine (T4) serum levels, resulting in increased hepatic activity of type 1 deiodinase (D1). In the mutants' brains, entry of T4 was not affected, but uptake of T3 was diminished. Moreover, the T4 and T3 content in the brain of MCT8-null mice was decreased, the activity of D2 was increased, and D3 activity was decreased, indicating the hypothyroid state of this tissue. In the CNS, analysis of T3 target genes revealed that in the mutants, the neuronal T3 uptake was impaired in an area-specific manner, with strongly elevated thyrotropin-releasing hormone transcript levels in the hypothalamic paraventricular nucleus and slightly decreased RC3 mRNA expression in striatal neurons; however, cerebellar Purkinje cells appeared unaffected, since they did not exhibit dendritic outgrowth defects and responded normally to T3 treatment in vitro. In conclusion, the circulating thyroid hormone levels of MCT8-null mice closely resemble those of humans with MCT8 mutations, yet in the mice, CNS development is only partially affected.

  5. Mice lacking integrin β3 expression exhibit altered response to chronic stress

    PubMed Central

    Varney, Seth; Polston, Keith F.; Jessen, Tammy; Carneiro, Ana M.D.

    2015-01-01

    Recent studies indicate multiple roles for integrin αvβ3 in adult neurons, including response to pharmacological agents such as cocaine and selective serotonin reuptake inhibitors. In this study, we examined the role of the integrin β3 gene (Itgb3) in the response to environmental stimuli by subjecting Itgb3+/+ and Itgb3−/− mice to unpredictable chronic mild stressors. We found that genetic abrogation of integrin β3 expression elicits an exaggerated vulnerability to chronic unpredictable stress in the open field test. In this test, chronic stress elicited significant decreases in stereotypic behavior and horizontal locomotor activity, including increases in anxiety behaviors. Mild chronic stress led to reductions in dopamine turnover in midbrains of Itgb3+/+, but not Itgb3−/− mice, suggesting a disruption of stress-dependent regulation of DA homeostasis. Chronic stress elicited altered synaptic expression of syntaxin and synaptophysin in midbrains of Itgb3−/− mice, when compared to Itgb3+/+. Semi-quantitative Western blot studies revealed that the synaptic expression, but not total tissue expression, of multiple signaling proteins is correlated with integrin αv levels in the midbrain. Moreover, loss of integrin β3 expression modifies this correlation network. Together, these findings demonstrate that Itgb3−/− mice display a pattern of changes indicating disrupted regulation of midbrain synaptic systems involved in conferring resilience to mild stressors. PMID:26634222

  6. Mice Lacking M1 and M3 Muscarinic Acetylcholine Receptors Have Impaired Odor Discrimination and Learning

    PubMed Central

    Chan, Wilson; Singh, Sanmeet; Keshav, Taj; Dewan, Ramita; Eberly, Christian; Maurer, Robert; Nunez-Parra, Alexia; Araneda, Ricardo C.

    2017-01-01

    The cholinergic system has extensive projections to the olfactory bulb (OB) where it produces a state-dependent regulation of sensory gating. Previous work has shown a prominent role of muscarinic acetylcholine (ACh) receptors (mAChRs) in regulating the excitability of OB neurons, in particular the M1 receptor. Here, we examined the contribution of M1 and M3 mAChR subtypes to olfactory processing using mice with a genetic deletion of these receptors, the M1−/− and the M1/M3−/− knockout (KO) mice. Genetic ablation of the M1 and M3 mAChRs resulted in a significant deficit in odor discrimination of closely related molecules, including stereoisomers. However, the discrimination of dissimilar molecules, social odors (e.g., urine) and novel object recognition was not affected. In addition the KO mice showed impaired learning in an associative odor-learning task, learning to discriminate odors at a slower rate, indicating that both short and long-term memory is disrupted by mAChR dysfunction. Interestingly, the KO mice exhibited decreased olfactory neurogenesis at younger ages, a deficit that was not maintained in older animals. In older animals, the olfactory deficit could be restored by increasing the number of new born neurons integrated into the OB after exposing them to an olfactory enriched environment, suggesting that muscarinic modulation and adult neurogenesis could be two different mechanism used by the olfactory system to improve olfactory processing. PMID:28210219

  7. Mice lacking synapsin III show abnormalities in explicit memory and conditioned fear.

    PubMed

    Porton, B; Rodriguiz, R M; Phillips, L E; Gilbert, J W; Feng, J; Greengard, P; Kao, H-T; Wetsel, W C

    2010-04-01

    Synapsin III is a neuron-specific phosphoprotein that plays an important role in synaptic transmission and neural development. While synapsin III is abundant in embryonic brain, expression of the protein in adults is reduced and limited primarily to the hippocampus, olfactory bulb and cerebral cortex. Given the specificity of synapsin III to these brain areas and because it plays a role in neurogenesis in the dentate gyrus, we investigated whether it may affect learning and memory processes in mice. To address this point, synapsin III knockout mice were examined in a general behavioral screen, several tests to assess learning and memory function, and conditioned fear. Mutant animals displayed no anomalies in sensory and motor function or in anxiety- and depressive-like behaviors. Although mutants showed minor alterations in the Morris water maze, they were deficient in object recognition 24 h and 10 days after training and in social transmission of food preference at 20 min and 24 h. In addition, mutants displayed abnormal responses in contextual and cued fear conditioning when tested 1 or 24 h after conditioning. The synapsin III knockout mice also showed aberrant responses in fear-potentiated startle. As synapsin III protein is decreased in schizophrenic brain and because the mutant mice do not harbor obvious anatomical deficits or neurological disorders, these mutants may represent a unique neurodevelopmental model for dissecting the molecular pathways that are related to certain aspects of schizophrenia and related disorders.

  8. Mice lacking synapsin III show abnormalities in explicit memory and conditioned fear

    PubMed Central

    Porton, Barbara; Rodriguiz, Ramona M.; Phillips, Lindsey E.; Gilbert, John W.; Feng, Jian; Greengard, Paul; Kao, Hung-Teh; Wetsel, William C.

    2010-01-01

    Synapsin III is a neuron-specific phosphoprotein that plays an important role in synaptic transmission and neural development. While synapsin III is abundant in embryonic brain, expression of the protein in adults is reduced and limited primarily to the hippocampus, olfactory bulb, and cerebral cortex. Given the specificity of synapsin III to these brain areas and because it plays a role in neurogenesis in the dentate gyrus, we investigated whether it may affect learning and memory processes in mice. To address this point, synapsin III knockout mice were examined in a general behavioral screen, several tests to assess learning and memory function, and conditioned fear. Mutant animals displayed no anomalies in sensory and motor function or in anxiety- and depressive-like behaviors. Although mutants showed minor alterations in the Morris water maze, they were deficient in object recognition 24 hr and 10 days after training and in social transmission of food preference at 20 min and 24 hr. Additionally, mutants displayed abnormal responses in contextual and cued fear conditioning when tested 1 or 24 hr after conditioning. The synapsin III knockout mice also showed aberrant responses in fear-potentiated startle. Since synapsin III protein is decreased in schizophrenic brain and because the mutant mice do not harbor obvious anatomical deficits or neurological disorders, these mutants may represent a unique neurodevelopmental model for dissecting the molecular pathways that are related to certain aspects of schizophrenia and related disorders. PMID:20050925

  9. Increased motor drive and sleep loss in mice lacking Kv3-type potassium channels.

    PubMed

    Espinosa, F; Marks, G; Heintz, N; Joho, R H

    2004-04-01

    The voltage-gated potassium channels Kv3.1 and Kv3.3 are widely expressed in the brain, including areas implicated in the control of motor activity and in areas thought to regulate arousal states. Although Kv3.1 and Kv3.3-single mutants show some physiological changes, previous studies revealed relatively subtle behavioral alterations suggesting that Kv3.1 and Kv3.3 channel subunits may be encoded by a pair of redundant genes. In agreement with this hypothesis, Kv3.1/Kv3.3-deficient mice display a 'strong' mutant phenotype that includes motor dysfunction (ataxia, myoclonus, tremor) and hyperactivity when exposed to a novel environment. In this paper we report that Kv3.1/Kv3.3-deficient mice are also constitutively hyperactive. Compared to wildtype mice, double mutants display 'restlessness' that is particularly prominent during the light period, when mice are normally at rest, characterized by more than a doubling of ambulatory and stereotypic activity, and accompanied by a 40% sleep reduction. When we reinvestigated both single mutants, we observed constitutive increases of ambulatory and stereotypic activity in conjunction with sleep loss in Kv3.1-single mutants but not in Kv3.3-single mutants. These findings indicate that the absence of Kv3.1-channel subunits is primarily responsible for the increased motor drive and the reduction in sleep time.

  10. Alcohol-induced bone loss is blocked in p47phox -/- mice lacking functional nadph oxidases

    USDA-ARS?s Scientific Manuscript database

    Chronic ethanol (EtOH) consumption produces bone loss. Previous data suggest a role for NADPH oxidase enzymes (Nox) since the pan-Nox inhibitor diphenylene iodonium (DPI) blocks EtOH-induced bone loss in rats. The current study utilized mice in which Nox enzymes 1,2,3 and 5 are inactivated as a resu...

  11. Hypertension in mice lacking 11β-hydroxysteroid dehydrogenase type 2

    PubMed Central

    Kotelevtsev, Yuri; Brown, Roger W.; Fleming, Stewart; Kenyon, Christopher; Edwards, Christopher R.W.; Seckl, Jonathan R.; Mullins, John J.

    1999-01-01

    Deficiency of 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) in humans leads to the syndrome of apparent mineralocorticoid excess (SAME), in which cortisol illicitly occupies mineralocorticoid receptors, causing sodium retention, hypokalemia, and hypertension. However, the disorder is usually incompletely corrected by suppression of cortisol, suggesting additional and irreversible changes, perhaps in the kidney. To examine this further, we produced mice with targeted disruption of the 11β-HSD2 gene. Homozygous mutant mice (11β-HSD2–/–) appear normal at birth, but ∼50% show motor weakness and die within 48 hours. Both male and female survivors are fertile but exhibit hypokalemia, hypotonic polyuria, and apparent mineralocorticoid activity of corticosterone. Young adult 11β-HSD2–/– mice are markedly hypertensive, with a mean arterial blood pressure of 146 ± 2 mmHg, compared with 121 ± 2 mmHg in wild-type controls and 114 ± 4 mmHg in heterozygotes. The epithelium of the distal tubule of the nephron shows striking hypertrophy and hyperplasia. These histological changes do not readily reverse with mineralocorticoid receptor antagonism in adulthood. Thus, 11β-HSD2–/– mice demonstrate the major features of SAME, providing a unique rodent model to study the molecular mechanisms of kidney resetting leading to hypertension. J. Clin. Invest. 103:683–689 (1999) PMID:10074485

  12. Skin fragility and impaired desmosomal adhesion in mice lacking all keratins.

    PubMed

    Bär, Janina; Kumar, Vinod; Roth, Wera; Schwarz, Nicole; Richter, Miriam; Leube, Rudolf E; Magin, Thomas M

    2014-04-01

    Keratins perform major structural and regulatory functions in epithelia. Owing to redundancy, their respective contribution to epidermal integrity, adhesion, and cell junction formation has not been addressed in full. Unexpectedly, the constitutive deletion of type II keratins in mice was embryonic lethal ∼ E9.5 without extensive tissue damage. This prompted us to analyze keratin functions in skin where keratins are best characterized. Here, we compare the mosaic and complete deletion of all type II keratins in mouse skin, with distinct consequences on epidermal integrity, adhesion, and organismal survival. Mosaic knockout (KO) mice survived ∼ 12 days while global KO mice died perinatally because of extensive epidermal damage. Coinciding with absence of keratins, epidermal fragility, inflammation, increased epidermal thickness, and increased proliferation were noted in both strains of mice, accompanied by significantly smaller desmosomes. Decreased desmosome size was due to accumulation of desmosomal proteins in the cytoplasm, causing intercellular adhesion defects resulting in intercellular splits. Mixing different ratios of wild-type and KO keratinocytes revealed that ∼ 60% of keratin-expressing cells were sufficient to maintain epithelial sheets under stress. Our data reveal a major contribution of keratins to the maintenance of desmosomal adhesion and epidermal integrity with relevance for the treatment of epidermolysis bullosa simplex and other keratinopathies.

  13. Impaired Discrimination Learning in Mice Lacking the NMDA Receptor NR2A Subunit

    ERIC Educational Resources Information Center

    Brigman, Jonathan L.; Feyder, Michael; Saksida, Lisa M.; Bussey, Timothy J.; Mishina, Masayoshi; Holmes, Andrew

    2008-01-01

    N-Methyl-D-aspartate receptors (NMDARs) mediate certain forms of synaptic plasticity and learning. We used a touchscreen system to assess NR2A subunit knockout mice (KO) for (1) pairwise visual discrimination and reversal learning and (2) acquisition and extinction of an instrumental response requiring no pairwise discrimination. NR2A KO mice…

  14. Generation and Characterization of Mice Lacking the Zinc Uptake Transporter ZIP3

    PubMed Central

    Dufner-Beattie, Jodi; Huang, Zhixin L.; Geiser, Jim; Xu, Wenhao; Andrews, Glen K.

    2005-01-01

    The mouse ZIP3 (SLC39A3) gene encodes an eight-transmembrane-domain protein that has been conserved in mammals and can function to transport zinc. To analyze the expression of ZIP3 in the early embryo and neonate and to determine its in vivo function, we generated ZIP3 null mice in which the ZIP3 open reading frame was replaced with that of the enhanced green fluorescent protein (EGFP) reporter. EGFP fluorescence revealed that ZIP3 was expressed in the inner cell mass of the blastocyst and later during embryonic development in many tissues. Elevated expression was apparent in the embryonic brain and neurotube and neonatal gonads. Homozygous knockout mice were viable and fertile and under normal growth conditions exhibited no obvious phenotypic abnormalities. Deletion of ZIP3 did not alter zinc homeostasis at the molecular level as assessed by essential metal levels and the expression of zinc-responsive genes. In knockout mice stressed with a zinc-deficient diet during pregnancy or at weaning, a subtle increase in the sensitivity to abnormal morphogenesis of the embryo and to depletion of thymic pre-T cells, respectively, was noted. These results suggest that this protein plays an ancillary role in zinc homeostasis in mice. PMID:15964816

  15. Analysis of cutaneous sensory neurons in transgenic mice lacking the low affinity neurotrophin receptor p75.

    PubMed

    Bergmann, I; Priestley, J V; McMahon, S B; Bröcker, E B; Toyka, K V; Koltzenburg, M

    1997-01-01

    Mice with a targeted mutation of the p75 low affinity neurotrophin receptor display smaller peripheral nerves and dorsal root ganglia. Here we show that transgenic mice have a significant elevation of thresholds to noxious mechanical and heat stimuli compared with p75+/+ control mice. Immunocytochemical analysis using antibodies against PGP 9.5 (a panaxonal marker) and calcitonin gene related peptide (CGRP, which labels peptidergic neurons) showed a reduction to 73% and 54%, respectively, of the epidermal innervation density. However, analysis of the cell size distribution of toluidine blue-stained dorsal root ganglia showed no selective loss of neurons of particular diameters. Moreover, the neurochemical profile of dorsal root ganglia cells as defined by trkA, CGRP, IB4 and RT97 immunostaining revealed no significant differences in comparison with p75+/+ animals. Staining of the dorsal horn of the spinal cord for CGRP and IB4 was also normal in p75-/- animals. Taking into account a previously reported loss of approximately 50% dorsal root ganglion neurons, we conclude that all types of sensory neurons are equally depleted in p75-/- mice and that the absence of p75 impedes the development of more than one neuronal subtype.

  16. Abnormal thyroid hormone metabolism in mice lacking the monocarboxylate transporter 8

    PubMed Central

    Trajkovic, Marija; Visser, Theo J.; Mittag, Jens; Horn, Sigrun; Lukas, Jan; Darras, Veerle M.; Raivich, Genadij; Bauer, Karl; Heuer, Heike

    2007-01-01

    In humans, inactivating mutations in the gene of the thyroid hormone transporter monocarboxylate transporter 8 (MCT8; SLC16A2) lead to severe forms of psychomotor retardation combined with imbalanced thyroid hormone serum levels. The MCT8-null mice described here, however, developed without overt deficits but also exhibited distorted 3,5,3′-triiodothyronine (T3) and thyroxine (T4) serum levels, resulting in increased hepatic activity of type 1 deiodinase (D1). In the mutants’ brains, entry of T4 was not affected, but uptake of T3 was diminished. Moreover, the T4 and T3 content in the brain of MCT8-null mice was decreased, the activity of D2 was increased, and D3 activity was decreased, indicating the hypothyroid state of this tissue. In the CNS, analysis of T3 target genes revealed that in the mutants, the neuronal T3 uptake was impaired in an area-specific manner, with strongly elevated thyrotropin-releasing hormone transcript levels in the hypothalamic paraventricular nucleus and slightly decreased RC3 mRNA expression in striatal neurons; however, cerebellar Purkinje cells appeared unaffected, since they did not exhibit dendritic outgrowth defects and responded normally to T3 treatment in vitro. In conclusion, the circulating thyroid hormone levels of MCT8-null mice closely resemble those of humans with MCT8 mutations, yet in the mice, CNS development is only partially affected. PMID:17318265

  17. Dwarfism and early death in mice lacking C-type natriuretic peptide

    PubMed Central

    Chusho, Hideki; Tamura, Naohisa; Ogawa, Yoshihiro; Yasoda, Akihiro; Suda, Michio; Miyazawa, Takashi; Nakamura, Kenji; Nakao, Kazuki; Kurihara, Tatsuya; Komatsu, Yasato; Itoh, Hiroshi; Tanaka, Kiyoshi; Saito, Yoshihiko; Katsuki, Motoya; Nakao, Kazuwa

    2001-01-01

    Longitudinal bone growth is determined by endochondral ossification that occurs as chondrocytes in the cartilaginous growth plate undergo proliferation, hypertrophy, cell death, and osteoblastic replacement. The natriuretic peptide family consists of three structurally related endogenous ligands, atrial, brain, and C-type natriuretic peptides (ANP, BNP, and CNP), and is thought to be involved in a variety of homeostatic processes. To investigate the physiological significance of CNP in vivo, we generated mice with targeted disruption of CNP (Nppc−/− mice). The Nppc−/− mice show severe dwarfism as a result of impaired endochondral ossification. They are all viable perinatally, but less than half can survive during postnatal development. The skeletal phenotypes are histologically similar to those seen in patients with achondroplasia, the most common genetic form of human dwarfism. Targeted expression of CNP in the growth plate chondrocytes can rescue the skeletal defect of Nppc−/− mice and allow their prolonged survival. This study demonstrates that CNP acts locally as a positive regulator of endochondral ossification in vivo and suggests its pathophysiological and therapeutic implication in some forms of skeletal dysplasia. PMID:11259675

  18. Impaired Discrimination Learning in Mice Lacking the NMDA Receptor NR2A Subunit

    ERIC Educational Resources Information Center

    Brigman, Jonathan L.; Feyder, Michael; Saksida, Lisa M.; Bussey, Timothy J.; Mishina, Masayoshi; Holmes, Andrew

    2008-01-01

    N-Methyl-D-aspartate receptors (NMDARs) mediate certain forms of synaptic plasticity and learning. We used a touchscreen system to assess NR2A subunit knockout mice (KO) for (1) pairwise visual discrimination and reversal learning and (2) acquisition and extinction of an instrumental response requiring no pairwise discrimination. NR2A KO mice…

  19. Mice lacking desmocollin 1 show epidermal fragility accompanied by barrier defects and abnormal differentiation.

    PubMed

    Chidgey, M; Brakebusch, C; Gustafsson, E; Cruchley, A; Hail, C; Kirk, S; Merritt, A; North, A; Tselepis, C; Hewitt, J; Byrne, C; Fassler, R; Garrod, D

    2001-11-26

    The desmosomal cadherin desmocollin (Dsc)1 is expressed in upper epidermis where strong adhesion is required. To investigate its role in vivo, we have genetically engineered mice with a targeted disruption in the Dsc1 gene. Soon after birth, null mice exhibit flaky skin and a striking punctate epidermal barrier defect. The epidermis is fragile, and acantholysis in the granular layer generates localized lesions, compromising skin barrier function. Neutrophils accumulate in the lesions and further degrade the tissue, causing sloughing (flaking) of lesional epidermis, but rapid wound healing prevents the formation of overt lesions. Null epidermis is hyperproliferative and overexpresses keratins 6 and 16, indicating abnormal differentiation. From 6 wk, null mice develop ulcerating lesions resembling chronic dermatitis. We speculate that ulceration occurs after acantholysis in the fragile epidermis because environmental insults are more stringent and wound healing is less rapid than in neonatal mice. This dermatitis is accompanied by localized hair loss associated with formation of utriculi and dermal cysts, denoting hair follicle degeneration. Possible resemblance of the lesions to human blistering diseases is discussed. These results show that Dsc1 is required for strong adhesion and barrier maintenance in epidermis and contributes to epidermal differentiation.

  20. Dwarfism and early death in mice lacking C-type natriuretic peptide.

    PubMed

    Chusho, H; Tamura, N; Ogawa, Y; Yasoda, A; Suda, M; Miyazawa, T; Nakamura, K; Nakao, K; Kurihara, T; Komatsu, Y; Itoh, H; Tanaka, K; Saito, Y; Katsuki, M; Nakao, K

    2001-03-27

    Longitudinal bone growth is determined by endochondral ossification that occurs as chondrocytes in the cartilaginous growth plate undergo proliferation, hypertrophy, cell death, and osteoblastic replacement. The natriuretic peptide family consists of three structurally related endogenous ligands, atrial, brain, and C-type natriuretic peptides (ANP, BNP, and CNP), and is thought to be involved in a variety of homeostatic processes. To investigate the physiological significance of CNP in vivo, we generated mice with targeted disruption of CNP (Nppc(-/-) mice). The Nppc(-/-) mice show severe dwarfism as a result of impaired endochondral ossification. They are all viable perinatally, but less than half can survive during postnatal development. The skeletal phenotypes are histologically similar to those seen in patients with achondroplasia, the most common genetic form of human dwarfism. Targeted expression of CNP in the growth plate chondrocytes can rescue the skeletal defect of Nppc(-/-) mice and allow their prolonged survival. This study demonstrates that CNP acts locally as a positive regulator of endochondral ossification in vivo and suggests its pathophysiological and therapeutic implication in some forms of skeletal dysplasia.

  1. Traumatic brain injury in mice lacking the K channel, TREK-1

    PubMed Central

    Namiranian, Khodadad; Brink, Christa D; Goodman, Jerry Clay; Robertson, Claudia S; Bryan, Robert M

    2011-01-01

    The purpose of this study was to determine whether the potassium channel, TREK-1, was neuroprotective after traumatic brain injury (TBI). Since there are no selective blockers, we used TREK-1 knockout (KO) mice for our study. Wild-type (WT) and TREK-1 KO mice were anesthetized and subjected to controlled-cortical impact injury (deformation of the brain by 1.5 mm by a 3-mm diameter rod traveling at a 3 m/s). Laser Doppler perfusion (LDP) decreased by ∼80% in the injured cortex and remained at that level in both WT and TREK-1 KO mice (n=10 and 11, respectively). Laser Doppler perfusion decreased by 50% to 60% in cortical areas directly adjacent to the site of injury. There were no statistical differences in LDP between genotype. The contusion volume, determined 15 days after the TBI using hematoxylin and eosin-stained coronal brain sections, was 4.1±0.8 (n=10) and 5.1±0.5 (n=11) mm3 for WT and TREK-1 KO, respectively (not significant, P=0.34). Cell counts of viable neurons in the CA1 and CA3 regions of the hippocampus were similar between WT and TREK-1 KO mice (P=0.51 and 0.84 for CA1 and CA3, respectively). We conclude that TREK-1 expression does not provide brain protection after TBI. PMID:21157470

  2. Mice lacking desmocollin 1 show epidermal fragility accompanied by barrier defects and abnormal differentiation

    PubMed Central

    Chidgey, Martyn; Brakebusch, Cord; Gustafsson, Erika; Cruchley, Alan; Hail, Chris; Kirk, Sarah; Merritt, Anita; North, Alison; Tselepis, Chris; Hewitt, Jane; Byrne, Carolyn; Fassler, Reinhard; Garrod, David

    2001-01-01

    The desmosomal cadherin desmocollin (Dsc)1 is expressed in upper epidermis where strong adhesion is required. To investigate its role in vivo, we have genetically engineered mice with a targeted disruption in the Dsc1 gene. Soon after birth, null mice exhibit flaky skin and a striking punctate epidermal barrier defect. The epidermis is fragile, and acantholysis in the granular layer generates localized lesions, compromising skin barrier function. Neutrophils accumulate in the lesions and further degrade the tissue, causing sloughing (flaking) of lesional epidermis, but rapid wound healing prevents the formation of overt lesions. Null epidermis is hyperproliferative and overexpresses keratins 6 and 16, indicating abnormal differentiation. From 6 wk, null mice develop ulcerating lesions resembling chronic dermatitis. We speculate that ulceration occurs after acantholysis in the fragile epidermis because environmental insults are more stringent and wound healing is less rapid than in neonatal mice. This dermatitis is accompanied by localized hair loss associated with formation of utriculi and dermal cysts, denoting hair follicle degeneration. Possible resemblance of the lesions to human blistering diseases is discussed. These results show that Dsc1 is required for strong adhesion and barrier maintenance in epidermis and contributes to epidermal differentiation. PMID:11714727

  3. DISTINCT BEHAVIORAL PHENOTYPES IN MALE MICE LACKING THE THYROID HORMONE RECEPTOR α1 OR β ISOFORMS

    PubMed Central

    Vasudevan, Nandini; Morgan, Maria; Pfaff, Donald; Ogawa, Sonoko

    2013-01-01

    Thyroid hormones influence both neuronal development and anxiety via the thyroid hormone receptors (TRs). The TRs are encoded by two different genes, TRα and TRβ. The loss of TRα1 is implicated in increased anxiety in males, possibly via a hippocampal increase in GABAergic activity. We compared both social behaviors and two underlying and related non-social behaviors, state anxiety and responses to acoustic and tactile startle in the gonadally intact TRα1 knockout (α1KO) and TRβ (βKO) male mice to their wild-type counterparts. For the first time, we show an opposing effect of the two TR isoforms, TRα1 and TRβ, in the regulation of state anxiety, with α1 knockout animals (α1KO) showing higher levels of anxiety and βKO males showing less anxiety compared to respective wild-type mice. At odds with the increased anxiety in non-social environments, α1KO males also show lower levels of responsiveness to acoustic and tactile startle stimuli. Consistent with the data that T4 is inhibitory to lordosis in female mice, we show subtly increased sex behavior in α1KO male mice. These behaviors support the idea that TRα1 could be inhibitory to ERα driven transcription that ultimately impacts ERα driven behaviors such as lordosis. The behavioral phenotypes point to novel roles for the TRs, particularly in non-social behaviors such as state anxiety and startle. PMID:23567476

  4. Accelerated tumor progression in mice lacking the ATP receptor P2X7.

    PubMed

    Adinolfi, Elena; Capece, Marina; Franceschini, Alessia; Falzoni, Simonetta; Giuliani, Anna L; Rotondo, Alessandra; Sarti, Alba C; Bonora, Massimo; Syberg, Susanne; Corigliano, Domenica; Pinton, Paolo; Jorgensen, Niklas R; Abelli, Luigi; Emionite, Laura; Raffaghello, Lizzia; Pistoia, Vito; Di Virgilio, Francesco

    2015-02-15

    The ATP receptor P2X7 (P2X7R or P2RX7) has a key role in inflammation and immunity, but its possible roles in cancer are not firmly established. In the present study, we investigated the effect of host genetic deletion of P2X7R in the mouse on the growth of B16 melanoma or CT26 colon carcinoma cells. Tumor size and metastatic dissemination were assessed by in vivo calliper and luciferase luminescence emission measurements along with postmortem examination. In P2X7R-deficient mice, tumor growth and metastatic spreading were accelerated strongly, compared with wild-type (wt) mice. Intratumoral IL-1β and VEGF release were drastically reduced, and inflammatory cell infiltration was abrogated nearly completely. Similarly, tumor growth was also greatly accelerated in wt chimeric mice implanted with P2X7R-deficient bone marrow cells, defining hematopoietic cells as a sufficient site of P2X7R action. Finally, dendritic cells from P2X7R-deficient mice were unresponsive to stimulation with tumor cells, and chemotaxis of P2X7R-less cells was impaired. Overall, our results showed that host P2X7R expression was critical to support an antitumor immune response, and to restrict tumor growth and metastatic diffusion. ©2014 American Association for Cancer Research.

  5. Mice lacking β3 integrins are osteosclerotic because of dysfunctional osteoclasts

    PubMed Central

    McHugh, Kevin P.; Hodivala-Dilke, Kairbaan; Zheng, Ming-Hao; Namba, Noriyuki; Lam, Jonathan; Novack, Deborah; Feng, Xu; Ross, F. Patrick; Hynes, Richard O.; Teitelbaum, Steven L.

    2000-01-01

    Osteoclasts express the αvβ3 integrin, an adhesion receptor that has been implicated in bone resorption and that is therefore a potential therapeutic target. To assess the role of this heterodimer in skeletal development in vivo, we engineered mice in which the gene for the β3 integrin subunit was deleted. Bone marrow macrophages derived from these mutants differentiate in vitro into numerous osteoclasts, thus establishing that αvβ3 is not necessary for osteoclast recruitment. Furthermore, the closely related integrin, αvβ5, does not substitute for αvβ3 during cytokine stimulation or authentic osteoclastogenesis. β3 knockout mice, but not their heterozygous littermates, develop histologically and radiographically evident osteosclerosis with age. Despite their increased bone mass, β3-null mice contain 3.5-fold more osteoclasts than do heterozygotes. These mutant osteoclasts are, however, dysfunctional, as evidenced by their reduced ability to resorb whale dentin in vitro and the significant hypocalcemia seen in the knockout mice. The resorptive defect in β3-deficient osteoclasts may reflect absence of matrix-derived intracellular signals, since their cytoskeleton is distinctly abnormal and they fail to spread in vitro, to form actin rings ex vivo, or to form normal ruffled membranes in vivo. Thus, although it is not required for osteoclastogenesis, the integrin αvβ3 is essential for normal osteoclast function. PMID:10683372

  6. Lack of genotoxic potential of pesticides, spinosad, imidacloprid and neem oil in mice (Mus musculus).

    PubMed

    Saxena, Ankita; Kesari, V P

    2016-03-01

    Pesticides, spinosad, imidacloprid and neem oil are widely used both in residential and agricultural environments because of its broad spectrum insecticidal activity and effectiveness. The present study was undertaken to estimate genotoxicity of formulations of some pesticides in mice. Three pesticides of diverse group studied were spinosad (45% w/v), imidacloprid (17.8%, w/v) and neem oil. Animals were exposed 37, 4.5 and 50 mg kg⁻¹ b.wt. for spinosad, imidacloprid and neem oil, respectively, through oral gavage for 5 consecutive days. A vehicle control group and one positive control (cyclophosphamide; 20 mg kg⁻¹ b. wt.) were also selected. The results showed that cyclophosphamide produced 1.12% micronuclei in mice, as against 0.18 in vehicle control, 0.30 in spinosad, 0.28 in imidacloprid and 0.22% in neem oil, respectively. The gross percentage of chromosomal aberration in mice were 28.5% in cyclophosphamide against 6.5% in vehicle control, 8.0% in spinosad, 9.5% in imidacloprid and 7.0% in neem oil, respectively. The overall findings of the present study revealed that all the three pesticide formulations, imidacloprid, spinosad and neem oil at tested dose did not show any genotoxic effect in mice.

  7. Communication Impairments in Mice Lacking Shank1: Reduced Levels of Ultrasonic Vocalizations and Scent Marking Behavior

    PubMed Central

    Wöhr, Markus; Roullet, Florence I.; Hung, Albert Y.; Sheng, Morgan; Crawley, Jacqueline N.

    2011-01-01

    Autism is a neurodevelopmental disorder with a strong genetic component. Core symptoms are abnormal reciprocal social interactions, qualitative impairments in communication, and repetitive and stereotyped patterns of behavior with restricted interests. Candidate genes for autism include the SHANK gene family, as mutations in SHANK2 and SHANK3 have been detected in several autistic individuals. SHANK genes code for a family of scaffolding proteins located in the postsynaptic density of excitatory synapses. To test the hypothesis that a mutation in SHANK1 contributes to the symptoms of autism, we evaluated Shank1−/− null mutant mice for behavioral phenotypes with relevance to autism, focusing on social communication. Ultrasonic vocalizations and the deposition of scent marks appear to be two major modes of mouse communication. Our findings revealed evidence for low levels of ultrasonic vocalizations and scent marks in Shank1−/− mice as compared to wildtype Shank1+/+ littermate controls. Shank1−/− pups emitted fewer vocalizations than Shank1+/+ pups when isolated from mother and littermates. In adulthood, genotype affected scent marking behavior in the presence of female urinary pheromones. Adult Shank1−/− males deposited fewer scent marks in proximity to female urine than Shank1+/+ males. Call emission in response to female urinary pheromones also differed between genotypes. Shank1+/+ mice changed their calling pattern dependent on previous female interactions, while Shank1−/− mice were unaffected, indicating a failure of Shank1−/− males to learn from a social experience. The reduced levels of ultrasonic vocalizations and scent marking behavior in Shank1−/− mice are consistent with a phenotype relevant to social communication deficits in autism. PMID:21695253

  8. Mice lacking Period 1 and Period 2 circadian clock genes exhibit blue cone photoreceptor defects.

    PubMed

    Ait-Hmyed, Ouafa; Felder-Schmittbuhl, Marie-Paule; Garcia-Garrido, Marina; Beck, Susanne; Seide, Christina; Sothilingam, Vithiyanjali; Tanimoto, Naoyuki; Seeliger, Mathias; Bennis, Mohammed; Hicks, David

    2013-04-01

    Many aspects of retinal physiology are modulated by circadian clocks, but it is unclear whether clock malfunction impinges directly on photoreceptor survival, differentiation or function. Eyes from wild-type (WT) and Period1 (Per1) and Period2 (Per2) mutant mice (Per1(Brdm1) Per2(Brdm1) ) were examined for structural (histology, in vivo imaging), phenotypical (RNA expression, immunohistochemistry) and functional characteristics. Transcriptional levels of selected cone genes [red/green opsin (Opn1mw), blue cone opsin (Opn1sw) and cone arrestin (Arr3)] and one circadian clock gene (RORb) were quantified by real-time polymerase chain reaction. Although there were no changes in general retinal histology or visual responses (electroretinograms) between WT and Per1(Brdm1) Per2(Brdm1) mice, compared with age-matched controls, Per1(Brdm1) Per2(Brdm1) mice showed scattered retinal deformations by fundus inspection. Also, mRNA expression levels and immunostaining of blue cone opsin were significantly reduced in mutant mice. Especially, there was an alteration in the dorsal-ventral patterning of blue cones. Decreased blue cone opsin immunoreactivity was present by early postnatal stages, and remained throughout maturation. General photoreceptor differentiation was retarded in young mutant mice. In conclusion, deletion of both Per1 and Per2 clock genes leads to multiple discrete changes in retina, notably patchy tissue disorganization, reductions in cone opsin mRNA and protein levels, and altered distribution. These data represent the first direct link between Per1 and Per2 clock genes, and cone photoreceptor differentiation and function. © 2013 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

  9. Mice Lacking the kf-1 Gene Exhibit Increased Anxiety- but not Despair-Like Behavior

    PubMed Central

    Tsujimura, Atsushi; Matsuki, Masato; Takao, Keizo; Yamanishi, Kiyofumi; Miyakawa, Tsuyoshi; Hashimoto-Gotoh, Tamotsu

    2008-01-01

    KF-1 was originally identified as a protein encoded by human gene with increased expression in the cerebral cortex of a patient with Alzheimer's disease. In mouse brain, kf-1 mRNA is detected predominantly in the hippocampus and cerebellum, and kf-1 gene expression is elevated also in the frontal cortex of rats after chronic antidepressant treatments. KF-1 mediates E2-dependent ubiquitination and may modulate cellular protein levels as an E3 ubiquitin ligase, though its target proteins are not yet identified. To elucidate the role of kf-1 in the central nervous system, we generated kf-1 knockout mice by gene targeting, using Cre-lox recombination. The resulting kf-1−/− mice were normal and healthy in appearance. Behavioral analyses revealed that kf-1−/− mice showed significantly increased anxiety-like behavior compared with kf-1+/+ littermates in the light/dark transition and elevated plus maze tests; however, no significant differences were observed in exploratory locomotion using the open field test or in behavioral despair using the forced swim and tail suspension tests. These observations suggest that KF-1 suppresses selectively anxiety under physiological conditions probably through modulating protein levels of its unknown target(s). Interestingly, kf-1−/− mice exhibited significantly increased prepulse inhibition, which is usually reduced in human schizophrenic patients. Thus, the kf-1−/− mice provide a novel animal model for elucidating molecular mechanisms of psychiatric diseases such as anxiety/depression, and may be useful for screening novel anxiolytic/antidepressant compounds. PMID:18958194

  10. High bone mass in mice lacking Cx37 because of defective osteoclast differentiation.

    PubMed

    Pacheco-Costa, Rafael; Hassan, Iraj; Reginato, Rejane D; Davis, Hannah M; Bruzzaniti, Angela; Allen, Matthew R; Plotkin, Lilian I

    2014-03-21

    Connexin (Cx) proteins are essential for cell differentiation, function, and survival in all tissues with Cx43 being the most studied in bone. We now report that Cx37, another member of the connexin family of proteins, is expressed in osteoclasts, osteoblasts, and osteocytes. Mice with global deletion of Cx37 (Cx37(-/-)) exhibit higher bone mineral density, cancellous bone volume, and mechanical strength compared with wild type littermates. Osteoclast number and surface are significantly lower in bone of Cx37(-/-) mice. In contrast, osteoblast number and surface and bone formation rate in bones from Cx37(-/-) mice are unchanged. Moreover, markers of osteoblast activity ex vivo and in vivo are similar to those of Cx37(+/+) littermates. sRANKL/M-CSF treatment of nonadherent Cx37(-/-) bone marrow cells rendered a 5-fold lower level of osteoclast differentiation compared with Cx37(+/+) cell cultures. Further, Cx37(-/-) osteoclasts are smaller and have fewer nuclei per cell. Expression of RANK, TRAP, cathepsin K, calcitonin receptor, matrix metalloproteinase 9, NFATc1, DC-STAMP, ATP6v0d1, and CD44, markers of osteoclast number, fusion, or activity, is lower in Cx37(-/-) osteoclasts compared with controls. In addition, nonadherent bone marrow cells from Cx37(-/-) mice exhibit higher levels of markers for osteoclast precursors, suggesting altered osteoclast differentiation. The reduction of osteoclast differentiation is associated with activation of Notch signaling. We conclude that Cx37 is required for osteoclast differentiation and fusion, and its absence leads to arrested osteoclast maturation and high bone mass in mice. These findings demonstrate a previously unrecognized role of Cx37 in bone homeostasis that is not compensated for by Cx43 in vivo.

  11. Mice lacking MAP kinase phosphatase-1 have enhanced MAP kinase activity and resistance to diet-induced obesity.

    PubMed

    Wu, J Julie; Roth, Rachel J; Anderson, Ethan J; Hong, Eun-Gyoung; Lee, Mi-Kyung; Choi, Cheol Soo; Neufer, P Darrell; Shulman, Gerald I; Kim, Jason K; Bennett, Anton M

    2006-07-01

    The mitogen-activated protein kinases (MAPK) play critical roles in the pathogenesis of diabetes and obesity. The MAPKs are inactivated by MAPK phosphatases (MKPs) either in the cytosol or nucleus. Here we show that mice lacking the nuclear-localized MKP, MKP-1 (mkp-1(-/-)), have enhanced Erk, p38 MAPK and c-Jun NH(2)-terminal kinase (JNK) activities in insulin-responsive tissues as compared with wild-type mice. Although JNK promotes insulin resistance, mkp-1(-/-) mice exhibited unimpaired insulin-mediated signaling and glucose homeostasis. We reconciled these results by demonstrating that in mkp-1(-/-) mice, JNK activity was increased in the nucleus, but not the cytosol. Significantly, mkp-1(-/-) mice are resistant to diet-induced obesity due to enhanced energy expenditure, but succumb to glucose intolerance on a high fat diet. These results suggest that nuclear regulation of the MAPKs by MKP-1 is essential for the management of metabolic homeostasis in a manner that is spatially uncoupled from the cytosolic actions of the MAPKs.

  12. Lack of Adrenomedullin Results in Microbiota Changes and Aggravates Azoxymethane and Dextran Sulfate Sodium-Induced Colitis in Mice

    PubMed Central

    Martínez-Herrero, Sonia; Larrayoz, Ignacio M.; Narro-Íñiguez, Judit; Villanueva-Millán, María J.; Recio-Fernández, Emma; Pérez-Matute, Patricia; Oteo, José A.; Martínez, Alfredo

    2016-01-01

    The link between intestinal inflammation, microbiota, and colorectal cancer is intriguing and the potential underlying mechanisms remain unknown. Here we evaluate the influence of adrenomedullin (AM) in microbiota composition and its impact on colitis with an inducible knockout (KO) mouse model for AM. Microbiota composition was analyzed in KO and wild type (WT) mice by massive sequencing. Colitis was induced in mice by administration of azoxymethane (AOM) followed by dextran sulfate sodium (DSS) in the drinking water. Colitis was evaluated using a clinical symptoms index, histopathological analyses, and qRT-PCR. Abrogation of the adm gene in the whole body was confirmed by PCR and qRT-PCR. KO mice exhibit significant changes in colonic microbiota: higher proportion of δ-Proteobacteria class; of Coriobacteriales order; and of other families and genera was observed in KO feces. Meanwhile these mice had a lower proportion of beneficial bacteria, such as Lactobacillus gasseri and Bifidobacterium choerinum. TLR4 gene expression was higher (p < 0.05) in KO animals. AM deficient mice treated with DSS exhibited a significantly worse colitis with profound weight loss, severe diarrhea, rectal bleeding, colonic inflammation, edema, infiltration, crypt destruction, and higher levels of pro-inflammatory cytokines. No changes were observed in the expression levels of adhesion molecules. In conclusion, we have shown that lack of AM leads to changes in gut microbiota population and in a worsening of colitis conditions, suggesting that endogenous AM is a protective mediator in this pathology. PMID:27965594

  13. Aberrant development of the suprachiasmatic nucleus and circadian rhythms in mice lacking the homeodomain protein Six6.

    PubMed

    Clark, Daniel D; Gorman, Michael R; Hatori, Megumi; Meadows, Jason D; Panda, Satchidananda; Mellon, Pamela L

    2013-02-01

    The suprachiasmatic nucleus (SCN) of the mammalian hypothalamus is the central pacemaker for peripheral and organismal circadian rhythms. The development of this hypothalamic structure depends on genetic programs throughout embryogenesis. We have investigated the role of the homeodomain transcription factor Six6 in the development of the SCN. We first showed that Six6 mRNA has circadian regulation in the mouse SCN. We then characterized the behavioral activity patterns of Six6-null mice under various photoperiod manipulations and stained their hypothalami using SCN-specific markers. Six6-null mice display abnormal patterns of circadian behavior indicative of SCN abnormalities. The ability of light exposure to reset rhythms correlates with the presence or absence of optic nerves, but all Six6-null mice show irregular rhythms. In contrast, wild-type mice with crushed optic nerves maintain regular rhythms regardless of light exposure. Using immunohistochemistry for arginine vasopressin (AVP), vasoactive intestinal polypeptide (VIP), and β-galactosidase, we demonstrated the lack of these SCN markers in all Six6-null mice regardless of the presence of optic nerve or partial circadian rhythms. Therefore, Six6 is required for the normal development of the SCN, and the Six6-null mouse can mount independent, although irregular, circadian rhythms despite the apparent absence of a histochemically defined SCN.

  14. Mice lacking the Cβ subunit of PKA are resistant to angiotensin II-induced cardiac hypertrophy and dysfunction

    PubMed Central

    2010-01-01

    Background PKA is a ubiquitous, multi-subunit cellular kinase that regulates a number of different physiological responses in response to cAMP, including metabolism, cell division, and cardiac function. Numerous studies have implicated altered PKA signaling in cardiac dysfunction. Recently, it has been shown that mice lacking the catalytic β subunit of PKA (PKA Cβ) are protected from age-related problems such as weight gain and enlarged livers, and we hypothesized that these mice might also be resistant to cardiomyopathy. Findings Angiotensin II (ang II) induced hypertension in both PKA Cβ null mice and their WT littermates. However, PKA Cβ null mice were resistant to a number of ang II-induced, cardiopathological effects observed in the WT mice, including hypertrophy, decreased diastolic performance, and enlarged left atria. Conclusion The Cβ subunit of PKA plays an important role in angiotensin-induced cardiac dysfunction. The Cβ null mouse highlights the potential of the PKA Cβ subunit as a pharmaceutical target for hypertrophic cardiac disease. PMID:21080942

  15. Aberrant Development of the Suprachiasmatic Nucleus and Circadian Rhythms in Mice Lacking the Homeodomain Protein Six6

    PubMed Central

    Clark, Daniel D.; Gorman, Michael R.; Hatori, Megumi; Meadows, Jason D.; Panda, Satchidananda; Mellon, Pamela L.

    2013-01-01

    The suprachiasmatic nucleus (SCN) of the mammalian hypothalamus is the central pacemaker for peripheral and organismal circadian rhythms. The development of this hypothalamic structure depends on genetic programs throughout embryogenesis. We have investigated the role of the homeodomain transcription factor Six6 in the development of the SCN. We first showed that Six6 mRNA has circadian regulation in the mouse SCN. We then characterized the behavioral activity patterns of Six6-null mice under various photoperiod manipulations and stained their hypothalami using SCN-specific markers. Six6-null mice display abnormal patterns of circadian behavior indicative of SCN abnormalities. The ability of light exposure to reset rhythms correlates with the presence or absence of optic nerves, but all Six6-null mice show irregular rhythms. In contrast, wild-type mice with crushed optic nerves maintain regular rhythms regardless of light exposure. Using immunohistochemistry for arginine vasopressin (AVP), vasoactive intestinal polypeptide (VIP), and β-galactosidase, we demonstrated the lack of these SCN markers in all Six6- null mice regardless of the presence of optic nerve or partial circadian rhythms. Therefore, Six6 is required for the normal development of the SCN, and the Six6-null mouse can mount independent, although irregular, circadian rhythms despite the apparent absence of a histochemically defined SCN. PMID:23382588

  16. Disruption of gene expression rhythms in mice lacking secretory vesicle proteins IA-2 and IA-2β.

    PubMed

    Punia, Sohan; Rumery, Kyle K; Yu, Elizabeth A; Lambert, Christopher M; Notkins, Abner L; Weaver, David R

    2012-09-15

    Insulinoma-associated protein (IA)-2 and IA-2β are transmembrane proteins involved in neurotransmitter secretion. Mice with targeted disruption of both IA-2 and IA-2β (double-knockout, or DKO mice) have numerous endocrine and physiological disruptions, including disruption of circadian and diurnal rhythms. In the present study, we have assessed the impact of disruption of IA-2 and IA-2β on molecular rhythms in the brain and peripheral oscillators. We used in situ hybridization to assess molecular rhythms in the hypothalamic suprachiasmatic nuclei (SCN) of wild-type (WT) and DKO mice. The results indicate significant disruption of molecular rhythmicity in the SCN, which serves as the central pacemaker regulating circadian behavior. We also used quantitative PCR to assess gene expression rhythms in peripheral tissues of DKO, single-knockout, and WT mice. The results indicate significant attenuation of gene expression rhythms in several peripheral tissues of DKO mice but not in either single knockout. To distinguish whether this reduction in rhythmicity reflects defective oscillatory function in peripheral tissues or lack of entrainment of peripheral tissues, animals were injected with dexamethasone daily for 15 days, and then molecular rhythms were assessed throughout the day after discontinuation of injections. Dexamethasone injections improved gene expression rhythms in liver and heart of DKO mice. These results are consistent with the hypothesis that peripheral tissues of DKO mice have a functioning circadian clockwork, but rhythmicity is greatly reduced in the absence of robust, rhythmic physiological signals originating from the SCN. Thus, IA-2 and IA-2β play an important role in the regulation of circadian rhythms, likely through their participation in neurochemical communication among SCN neurons.

  17. Catecholamine synthesis and metabolism in the central nervous system of mice lacking alpha-adrenoceptor subtypes.

    PubMed

    Vieira-Coelho, M A; Serrão, M P; Afonso, J; Pinto, C E; Moura, E

    2009-10-01

    This study investigates the role of alpha(2)-adrenoceptor subtypes, alpha(2A), alpha(2B) and alpha(2C), on catecholamine synthesis and catabolism in the central nervous system of mice. Activities of the main catecholamine synthetic and catabolic enzymes were determined in whole brains obtained from alpha(2A)-, alpha(2B)- and alpha(2C)-adrenoceptor knockout (KO) and C56Bl\\7 wild-type (WT) mice. Although no significant differences were found in tyrosine hydroxylase activity and expression, brain tissue levels of 3,4-dihydroxyphenylalanine were threefold higher in alpha(2A)- and alpha(2C)-adrenoceptor KO mice. Brain tissue levels of dopamine and noradrenaline were significantly higher in alpha(2A) and alpha(2C)KOs compared with WT [WT: 2.8 +/- 0.5, 1.1 +/- 0.1; alpha(2A)KO: 6.9 +/- 0.7, 1.9 +/- 0.1; alpha(2B)KO: 2.3 +/- 0.2, 1.0 +/- 0.1; alpha(2C)KO: 4.6 +/- 0.8, 1.5 +/- 0.2 nmol.(g tissue)(-1), for dopamine and noradrenaline respectively]. Aromatic L-amino acid decarboxylase activity was significantly higher in alpha(2A) and alpha(2C)KO [WT: 40 +/- 1; alpha(2A): 77 +/- 2; alpha(2B): 40 +/- 1; alpha(2C): 50 +/- 1, maximum velocity (V(max)) in nmol.(mg protein)(-1).h(-1)], but no significant differences were found in dopamine beta-hydroxylase. Of the catabolic enzymes, catechol-O-methyltransferase enzyme activity was significantly higher in all three alpha(2)KO mice [WT: 2.0 +/- 0.0; alpha(2A): 2.4 +/- 0.1; alpha(2B): 2.2 +/- 0.0; alpha(2C): 2.2 +/- 0.0 nmol.(mg protein)(-1).h(-1)], but no significant differences were found in monoamine oxidase activity between all alpha(2)KOs and WT mice. In mouse brain, deletion of alpha(2A)- or alpha(2C)-adrenoceptors increased cerebral aromatic L-amino acid decarboxylase activity and catecholamine tissue levels. Deletion of any alpha(2)-adrenoceptor subtypes resulted in increased activity of catechol-O-methyltransferase. Higher 3,4-dihydroxyphenylalanine tissue levels in alpha(2A) and alpha(2C)KO mice could be explained by

  18. Ryanodine-mediated conversion of STP to LTP is lacking in synaptopodin-deficient mice.

    PubMed

    Grigoryan, Gayane; Segal, Menahem

    2016-05-01

    In previous studies we and others have found that activation of ryanodine receptors (RyRs) facilitate expression of long-term potentiation (LTP) of reactivity to afferent stimulation in hippocampal slices, with a more pronounced action in the ventral hippocampus. We have also been able to link the involvement of synaptopodin (SP), an actin-binding protein, with neuronal plasticity via its interaction with RyRs. To test this link more directly, we have now compared the ability of ryanodine to convert short-term to LTP in hippocampal slices taken from normal and SP-knockout (SPKO) mice. Indeed, SPKO hippocampus expresses lower concentrations of RyRs and in slices of these mice ryanodine is unable to facilitate conversion of short-term to LTP. These observations link functionally SP with calcium stores.

  19. The transient outward current in mice lacking the potassium channel gene Kv1.4

    PubMed Central

    London, Barry; Wang, Dao W; Hill, Joseph A; Bennett, Paul B

    1998-01-01

    The transient outward current (Ito) plays a prominent role in the repolarization phase of the cardiac action potential. Several K+ channel genes, including Kv1.4, are expressed in the heart, produce rapidly inactivating currents when heterologously expressed, and may be the molecular basis of Ito.We engineered mice homozygous for a targeted disruption of the K+ channel gene Kv1.4 and compared Ito in wild-type (Kv1.4+/+), heterozygous (Kv1.4+/-) and homozygous ‘knockout’ (Kv1.4−/−) mice. Kv1.4 RNA was truncated in Kv1.4−/− mice and protein expression was absent.Adult myocytes isolated from Kv1.4+/+, Kv1.4+/− and Kv1.4−/− mice had large rapidly inactivating outward currents. The peak current densities at 60 mV (normalized by cellular capacitance, in pA pF−1; means ± s.e.m.) were 53.8 ± 5.3, 45.3 ± 2.2 and 44.4 ± 2.8 in cells from Kv1.4+/+, Kv1.4+/− and Kv1.4−/− mice, respectively (P < 0.02 for Kv1.4+/+ vs. Kv1.4−/−). The steady-state values (800 ms after the voltage clamp step) were 30.9 ± 2.9, 26.9 ± 3.8 and 23.5 ± 2.2, respectively (P < 0.02 for Kv1.4+/+ vs. Kv1.4−/−). The inactivating portion of the current was unchanged in the targeted mice.The voltage dependence and time course of inactivation were not changed by targeted disruption of Kv1.4. The mean best-fitting V½ (membrane potential at 50 % inactivation) values for myocytes from Kv1.4 +/+, Kv1.4+/− and Kv1.4−/− mice were -53.5 ± 3.7, -51.1 ± 2.6 and -54.2 ± 2.4 mV, respectively. The slope factors (k) were -10.1 ± 1.4, -8.8 ± 1.4 and -9.5 ± 1.2 mV, respectively. The fast time constants for development of inactivation at -30 mV were 27.8 ± 2.2, 26.2 ± 5.1 and 19.6 ± 2.1 ms in Kv1.4+/+, Kv1.4+/− and Kv1.4−/− myocytes, respectively. At +30 mV, they were 35.5 ± 2.6, 30.0 ± 2.1 and 28.7 ± 1.6 ms, respectively. The time constants for the rapid phase of recovery from inactivation at -80 mV were 32.5 ± 8.2, 23.3 ± 1.8 and 39.0 ± 3.7 ms, respectively

  20. Increased calcium bioavailability in mice fed genetically engineered plants lacking calcium oxalate.

    PubMed

    Morris, Jay; Nakata, Paul A; McConn, Michele; Brock, Amanda; Hirschi, Kendal D

    2007-07-01

    Bioavailable calcium affects bone formation and calcification. Here we investigate how a single gene mutation altering calcium partitioning in the model forage crop Medicago truncatula affects calcium bioavailability. Previously, the cod5 M. truncatula mutant was identified which contains identical calcium concentrations to wild-type, but contains no oxalate crystals. In this study, equal number of male and female mice were randomly grouped and then fed one of four 45Ca-containing diets: M. truncatula extrinsically or intrinsically labeled, and cod5 extrinsically or intrinsically labeled. Absorption of the tracer was determined in the legs one day after consumption. The absorption was similar in the M. truncatula and cod5 extrinsically labeled diets; however, in the intrinsically labeled diets, calcium absorption was 22.87% (P < 0.001) higher in mice fed cod5. Our study presents the first genetic evidence demonstrating the nutritional impact of removing oxalate crystals from foods.

  1. Impaired 17,20-Lyase Activity in Male Mice Lacking Cytochrome b5 in Leydig Cells

    PubMed Central

    Sondhi, Varun; Owen, Bryn M.; Liu, Jiayan; Chomic, Robert; Kliewer, Steven A.; Hughes, Beverly A.; Arlt, Wiebke; Mangelsdorf, David J.

    2016-01-01

    Androgen and estrogen biosynthesis in mammals requires the 17,20-lyase activity of cytochrome P450 17A1 (steroid 17-hydroxylase/17,20-lyase). Maximal 17,20-lyase activity in vitro requires the presence of cytochrome b5 (b5), and rare cases of b5 deficiency in human beings causes isolated 17,20-lyase deficiency. To study the consequences of conditional b5 removal from testicular Leydig cells in an animal model, we generated Cyb5flox/flox:Sf1-Cre (LeyKO) mice. The LeyKO male mice had normal body weights, testis and sex organ weights, and fertility compared with littermates. Basal serum and urine steroid profiles of LeyKO males were not significantly different than littermates. In contrast, marked 17-hydroxyprogesterone accumulation (100-fold basal) and reduced testosterone synthesis (27% of littermates) were observed after human chorionic gonadotropin stimulation in LeyKO animals. Testis homogenates from LeyKO mice showed reduced 17,20-lyase activity and a 3-fold increased 17-hydroxylase to 17,20-lyase activity ratio, which were restored to normal upon addition of recombinant b5. We conclude that Leydig cell b5 is required for maximal androgen synthesis and to prevent 17-hydroxyprogesterone accumulation in the mouse testis; however, the b5-independent 17,20-lyase activity of mouse steroid 17-hydroxylase/17,20-lyase is sufficient for normal male genital development and fertility. LeyKO male mice are a good model for the biochemistry but not the physiology of isolated 17,20-lyase deficiency in human beings. PMID:26974035

  2. Mesocortical Dopamine Phenotypes in Mice Lacking the Sonic Hedgehog Receptor Cdon

    PubMed Central

    Grant, Alanna; Meti, Nicholas; Adye-White, Lauren; Rioux, Veronique

    2016-01-01

    Abstract Motivated behaviors and many psychopathologies typically involve changes in dopamine release from the projections of the ventral tegmental area (VTA) and/or the substantia nigra pars compacta (SNc). The morphogen Sonic Hedgehog (Shh) specifies fates of midbrain dopamine neurons, but VTA-specific effects of Shh signaling are also being uncovered. In this study, we assessed the role of the Shh receptor Cdon in the development of VTA and SNc dopamine neurons. We find that Cdon is expressed in the proliferating progenitor zone of the embryonic ventral midbrain and that the number of proliferating cells in this region is increased in mouse Cdon−/− embryos. Consistent with a role of Shh in the regulation of neuronal proliferation in this region, we find that the number of tyrosine hydroxylase (TH)-positive neurons is increased in the VTA of Cdon−/− mice at birth and that this effect endures into adulthood. In contrast, the number of TH-positive neurons in the SNc is not altered in Cdon−/− mice at either age. Moreover, adult Cdon−/− mice have a greater number of medial prefrontal cortex (mPFC) dopamine presynaptic sites, and increased baseline concentrations of dopamine and dopamine metabolites selectively in this region. Finally, consistent with increased dopamine function in the mPFC, we find that adult Cdon−/− mice fail to exhibit behavioral plasticity upon repeated amphetamine treatment. Based on these data, we suggest that Cdon plays an important role encoding the diversity of dopamine neurons in the midbrain, influencing both the development of the mesocortical dopamine pathway and behavioral outputs that involve this neural circuitry. PMID:27419218

  3. Neurodegeneration and motor dysfunction in mice lacking cytosolic and mitochondrial aldehyde dehydrogenases: implications for Parkinson's disease.

    PubMed

    Wey, Margaret Chia-Ying; Fernandez, Elizabeth; Martinez, Paul Anthony; Sullivan, Patricia; Goldstein, David S; Strong, Randy

    2012-01-01

    Previous studies have reported elevated levels of biogenic aldehydes in the brains of patients with Parkinson's disease (PD). In the brain, aldehydes are primarily detoxified by aldehyde dehydrogenases (ALDH). Reduced ALDH1 expression in surviving midbrain dopamine neurons has been reported in brains of patients who died with PD. In addition, impaired complex I activity, which is well documented in PD, reduces the availability of the NAD(+) co-factor required by multiple ALDH isoforms to catalyze the removal of biogenic aldehydes. We hypothesized that chronically decreased function of multiple aldehyde dehydrogenases consequent to exposure to environmental toxins and/or reduced ALDH expression, plays an important role in the pathophysiology of PD. To address this hypothesis, we generated mice null for Aldh1a1 and Aldh2, the two isoforms known to be expressed in substantia nigra dopamine neurons. Aldh1a1(-/-)×Aldh2(-/-) mice exhibited age-dependent deficits in motor performance assessed by gait analysis and by performance on an accelerating rotarod. Intraperitoneal administration of L-DOPA plus benserazide alleviated the deficits in motor performance. We observed a significant loss of neurons immunoreactive for tyrosine hydroxylase (TH) in the substantia nigra and a reduction of dopamine and metabolites in the striatum of Aldh1a1(-/-)×Aldh2(-/-) mice. We also observed significant increases in biogenic aldehydes reported to be neurotoxic, including 4-hydroxynonenal (4-HNE) and the aldehyde intermediate of dopamine metabolism, 3,4-dihydroxyphenylacetaldehyde (DOPAL). These results support the hypothesis that impaired detoxification of biogenic aldehydes may be important in the pathophysiology of PD and suggest that Aldh1a1(-/-)×Aldh2(-/-) mice may be a useful animal model of PD.

  4. Mesocortical Dopamine Phenotypes in Mice Lacking the Sonic Hedgehog Receptor Cdon.

    PubMed

    Verwey, Michael; Grant, Alanna; Meti, Nicholas; Adye-White, Lauren; Torres-Berrío, Angelica; Rioux, Veronique; Lévesque, Martin; Charron, Frederic; Flores, Cecilia

    2016-01-01

    Motivated behaviors and many psychopathologies typically involve changes in dopamine release from the projections of the ventral tegmental area (VTA) and/or the substantia nigra pars compacta (SNc). The morphogen Sonic Hedgehog (Shh) specifies fates of midbrain dopamine neurons, but VTA-specific effects of Shh signaling are also being uncovered. In this study, we assessed the role of the Shh receptor Cdon in the development of VTA and SNc dopamine neurons. We find that Cdon is expressed in the proliferating progenitor zone of the embryonic ventral midbrain and that the number of proliferating cells in this region is increased in mouse Cdon(-/-) embryos. Consistent with a role of Shh in the regulation of neuronal proliferation in this region, we find that the number of tyrosine hydroxylase (TH)-positive neurons is increased in the VTA of Cdon(-/-) mice at birth and that this effect endures into adulthood. In contrast, the number of TH-positive neurons in the SNc is not altered in Cdon(-/-) mice at either age. Moreover, adult Cdon(-/-) mice have a greater number of medial prefrontal cortex (mPFC) dopamine presynaptic sites, and increased baseline concentrations of dopamine and dopamine metabolites selectively in this region. Finally, consistent with increased dopamine function in the mPFC, we find that adult Cdon(-/-) mice fail to exhibit behavioral plasticity upon repeated amphetamine treatment. Based on these data, we suggest that Cdon plays an important role encoding the diversity of dopamine neurons in the midbrain, influencing both the development of the mesocortical dopamine pathway and behavioral outputs that involve this neural circuitry.

  5. Combined low calcium and lack magnesium is a risk factor for motor deficit in mice.

    PubMed

    Taniguchi, Ryoo; Nakagawasai, Osamu; Tan-no, Koichi; Yamadera, Fumihiro; Nemoto, Wataru; Sato, Shoko; Yaoita, Fukie; Tadano, Takeshi

    2013-01-01

    The populations of the Kii Peninsula in Japan and of Guam present high incidences of amyotrophic lateral sclerosis and Parkinsonism-dementia complex. It is thought that low levels of calcium (Ca) and magnesium (Mg) in the drinking water are involved in the pathogenesis of these diseases. The present study aimed to test the hypothesis that catalepsy, behavioral immobility and a Parkinsonian symptom results from functionally impaired dopaminergic neurons in mice fed low amounts of Ca and Mg (LCa/Mg). A group of mice fed a LCa/Mg diet for 6 weeks was compared to a control group on a standard diet. Cataleptic symptoms such as akinesia and rigidity were measured by the bar test. The anti-parkinsonian drugs dopamine (DA) precursor L-3,4-dihydroxy phenylamine (L-DOPA), the selective DA receptor D(2) agonist bromocriptine, and the DA releaser amantadine were tested for their effects on induced catalepsy. The mice developed catalepsy after 3 weeks on the LCa/Mg diet. LCa/Mg diet-induced catalepsy was improved by the administration of L-DOPA (50-200 mg/kg i.p.) in combination with benserazide (25 mg/kg i.p.), or of bromocriptine (0.25-4 mg/kg i.p.) or of amantadine (5-20 mg/kg i.p.). Immunohistochemical staining revealed that the intensity of tyrosine hydroxylase fluorescence was significantly decreased in the substantia nigra at the 6th week of LCa/Mg feeding in comparison with pair-fed controls. These results suggest that catalepsy in LCa/Mg mice results from hypofunction of the dopaminergic neurons. Moreover, our results support the hypothesis that LCa/Mg intake is one etiological factor in neurodegenerative disorders, including Parkinson's disease.

  6. Increased Insulin Sensitivity in Mice Lacking Collectrin, a Downstream Target of HNF-1α

    PubMed Central

    Malakauskas, Sandra M.; Kourany, Wissam M.; Zhang, Xiao Yin; Lu, Danhong; Stevens, Robert D.; Koves, Timothy R.; Hohmeier, Hans E.; Muoio, Deborah M.; Newgard, Christopher B.; Le, Thu H.

    2009-01-01

    Collectrin is a downstream target of the transcription factor hepatocyte nuclear factor-1α (HNF-1α), which is mutated in maturity-onset diabetes of the young subtype 3 (MODY3). Evidence from transgenic mouse models with collectrin overexpression in pancreatic islets suggests divergent roles for collectrin in influencing β-cell mass and insulin exocytosis. To clarify the function of collectrin in the pancreas, we used a mouse line with targeted deletion of the gene. We examined pancreas morphology, glucose homeostasis by ip glucose tolerance testing (IPGTT) and insulin tolerance testing (IPITT), and pancreas function by in vivo acute-phase insulin response determination and glucose-stimulated insulin secretion from isolated islets. We find no difference in either pancreas morphology or function between wild-type and collectrin-deficient animals (Tmem27−/y). However, we note that by 6 months of age, Tmem27−/y mice exhibit increased insulin sensitivity by IPITT and decreased adiposity by dual-energy x-ray absorptiometry scanning compared with wild-type. We have previously reported that Tmem27−/y mice exhibit profound aminoaciduria due to failed renal recovery. We now demonstrate that Tmem27−/y animals also display inappropriate excretion of some short-chain acylcarnitines derived from amino acid and fatty acid oxidation. We provide further evidence for compensatory up-regulation of oxidative metabolism in Tmem27−/y mice, along with enhanced protein turnover associated with preserved lean mass even out to 1.5 yr of age. Our studies suggest that collectrin-deficient mice activate a number of adaptive mechanisms to defend energy homeostasis in the setting of ongoing nutrient losses. PMID:19246514

  7. Lack of an adrenal cortex in Sf1 mutant mice is compatible with the generation and differentiation of chromaffin cells.

    PubMed

    Gut, Philipp; Huber, Katrin; Lohr, Jennifer; Brühl, Barbara; Oberle, Stephan; Treier, Mathias; Ernsberger, Uwe; Kalcheim, Chaya; Unsicker, Klaus

    2005-10-01

    The diversification of neural-crest-derived sympathoadrenal (SA) progenitor cells into sympathetic neurons and neuroendocrine adrenal chromaffin cells was thought to be largely understood. In-vitro studies with isolated SA progenitor cells had suggested that chromaffin cell differentiation depends crucially on glucocorticoids provided by adrenal cortical cells. However, analysis of mice lacking the glucocorticoid receptor gene had revealed that adrenal chromaffin cells develop mostly normally in these mice. Alternative cues from the adrenal cortex that may promote chromaffin cell determination and differentiation have not been identified. We therefore investigated whether the chromaffin cell phenotype can develop in the absence of an adrenal cortex, using mice deficient for the nuclear orphan receptor steroidogenic factor-1 (SF1), which lack adrenal cortical cells and gonads. We show that in Sf1-/- mice typical chromaffin cells assemble correctly in the suprarenal region adjacent to the suprarenal sympathetic ganglion. The cells display most features of chromaffin cells, including the typical large chromaffin granules. Sf1-/- chromaffin cells are numerically reduced by about 50% compared with the wild type at embryonic day (E) 13.5 and E17.5. This phenotype is not accounted for by reduced survival or cell proliferation beyond E12.5. However, already at E12.5 the 'adrenal' region in Sf1-/- mice is occupied by fewer PHOX2B+ and TH+ SA cells as well as SOX10+ neural crest cells. Our results suggest that cortical cues are not essential for determining chromaffin cell fate, but may be required for proper migration of SA progenitors to and/or colonization of the adrenal anlage.

  8. Female mice lack adult germ-line stem cells but sustain oogenesis using stable primordial follicles.

    PubMed

    Lei, Lei; Spradling, Allan C

    2013-05-21

    Whether or not mammalian females generate new oocytes during adulthood from germ-line stem cells to sustain the ovarian follicle pool has recently generated controversy. We used a sensitive lineage-labeling system to determine whether stem cells are needed in female adult mice to compensate for follicular losses and to directly identify active germ-line stem cells. Primordial follicles generated during fetal life are highly stable, with a half-life during adulthood of 10 mo, and thus are sufficient to sustain adult oogenesis without a source of renewal. Moreover, in normal mice or following germ-cell depletion with Busulfan, only stable, single oocytes are lineage-labeled, rather than cell clusters indicative of new oocyte formation. Even one germ-line stem cell division per 2 wk would have been detected by our method, based on the kinetics of fetal follicle formation. Thus, adult female mice neither require nor contain active germ-line stem cells or produce new oocytes in vivo.

  9. Decreased parvalbumin immunoreactivity in the cortex and striatum of mice lacking the CB1 receptor

    PubMed Central

    Fitzgerald, Megan L.; Lupica, Carl R.; Pickel, Virginia M.

    2011-01-01

    Cortical and striatal regions of the brain contain high levels of the cannabinoid-1 (CB1) receptor, the central neuronal mediator of activity-dependent synaptic plasticity evoked by endocannabinoids. The expression levels of parvalbumin, a calcium-binding protein found in fast-spiking interneurons of both regions, may be controlled in part by synaptic activity during critical periods of development. However, there is presently no evidence that CB1 receptor expression affects parvalbumin levels in either cortical or striatal interneurons. To assess this possibility, we examined parvalbumin immunoreactivity in the dorsolateral striatum, primary motor cortex (M1), and prefrontal cortex (PFC) of CB1 knockout and wild-type C57/BL6 mice. Quantitative densitometry showed a significant decrease in parvalbumin immunoreactivity within individual neurons in each of these regions of CB1 knockout mice relative to the controls. A significantly lower density (number of cells per unit area) of parvalbumin-labeled neurons was observed in the striatum, but not the cortical regions of CB1 knockout mice. These findings suggest that CB1 receptor deletion may elicit a compensatory mechanism for network homeostasis affecting parvalbumin-containing cortical and striatal interneurons. PMID:21445945

  10. Purkinje cell degeneration in mice lacking the xeroderma pigmentosum group G gene.

    PubMed

    Sun, X Z; Harada, Y N; Takahashi, S; Shiomi, N; Shiomi, T

    2001-05-15

    Laboratory mice carrying the nonfunctional xeroderma pigmentosum group G gene (the mouse counterpart of the human XPG gene) alleles have been generated by using gene-targeting and embryonic stem cell technology. Homozygote animals of this autosomal recessive disease exhibited signs and symptoms, such as postnatal growth retardation, reduced levels of activity, progressive ataxia and premature death, similar to the clinical manifestations of Cockayne syndrome (CS). Histological analysis of the cerebellum revealed multiple pyknotic cells in the Purkinje cell layer of the xpg homozygotes, which had atrophic cell bodies and shrunken nuclei. Further examination by an immunohistochemistry for calbindin-D 28k (CaBP) showed that a large number of immunoreactive Purkinje cells were atrophic and their dendritic trees were smaller and shorter than in wild-type littermates. These results indicated a marked degeneration of Purkinje cells in the xpg mutant cerebellum. Study by in situ detection of DNA fragmentation in the cerebellar cortex demonstrated that some deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin in situ nick labeling (TUNEL)-positive cells appeared in the granule layer of the mutant mice, but few cell deaths were confirmed in the Purkinje layer. These results suggested Purkinje cell degeneration in the mutant cerebellum was underway, in which much Purkinje cell death had not appeared, and the appearance of some abnormal cerebellar symptoms in the xpg-deficient mice was not only due to a marked Purkinje cell degeneration, but also to damage of other cells.

  11. Lessons on renal physiology from transgenic mice lacking aquaporin water channels.

    PubMed

    Verkman, A S

    1999-05-01

    Several aquaporin-type water channels are expressed in kidney: AQP1 in the proximal tubule, thin descending limb of Henle, and vasa recta; AQP2, AQP3, and AQP4 in the collecting duct; AQP6 in the papilla; and AQP7 in the proximal tubule. AQP2 is the vasopressin-regulated water channel that is important in hereditary and acquired diseases affecting urine-concentrating ability. It has been difficult to establish the roles of the other aquaporins in renal physiology because suitable aquaporin inhibitors are not available. One approach to the problem has been to generate and analyze transgenic knockout mice in which individual aquaporins have been selectively deleted by targeted gene disruption. Phenotype analysis of kidney and extrarenal function in knockout mice has been very informative in defining the role of aquaporins in organ physiology and addressing basic questions regarding the route of transepithelial water transport and the mechanism of near iso-osmolar fluid reabsorption. This article describes new renal physiologic insights revealed by phenotype analysis of aquaporin-knockout mice and the prospects for further basic and clinical developments.

  12. Increased vulnerability to cocaine in mice lacking dopamine D3 receptors.

    PubMed

    Song, Rui; Zhang, Hai-Ying; Li, Xia; Bi, Guo-Hua; Gardner, Eliot L; Xi, Zheng-Xiong

    2012-10-23

    Neuroimaging studies using positron emission tomography suggest that reduced dopamine D(2) receptor availability in the neostriatum is associated with increased vulnerability to drug addiction in humans and experimental animals. The role of D(3) receptors (D(3)Rs) in the neurobiology of addiction remains unclear, however. Here we report that D(3)R KO (D(3)(-/-)) mice display enhanced cocaine self-administration and enhanced motivation for cocaine-taking and cocaine-seeking behavior. This increased vulnerability to cocaine is accompanied by decreased dopamine response to cocaine secondary to increased basal levels of extracellular dopamine in the nucleus accumbens, suggesting a compensatory response to decreased cocaine reward in D(3)(-/-) mice. In addition, D(3)(-/-) mice also display up-regulation of dopamine transporters in the striatum, suggesting a neuroadaptative attempt to normalize elevated basal extracellular dopamine. These findings suggest that D(3)R deletion increases vulnerability to cocaine, and that reduced D(3)R availability in the brain may constitute a risk factor for the development of cocaine addiction.

  13. Mice Lacking Pannexin 1 Release ATP and Respond Normally to All Taste Qualities

    PubMed Central

    Anderson, Catherine B.; Kinnamon, Sue C.

    2015-01-01

    Adenosine triphosphate (ATP) is required for the transmission of all taste qualities from taste cells to afferent nerve fibers. ATP is released from Type II taste cells by a nonvesicular mechanism and activates purinergic receptors containing P2X2 and P2X3 on nerve fibers. Several ATP release channels are expressed in taste cells including CALHM1, Pannexin 1, Connexin 30, and Connexin 43, but whether all are involved in ATP release is not clear. We have used a global Pannexin 1 knock out (Panx1 KO) mouse in a series of in vitro and in vivo experiments. Our results confirm that Panx1 channels are absent in taste buds of the knockout mice and that other known ATP release channels are not upregulated. Using a luciferin/luciferase assay, we show that circumvallate taste buds from Panx1 KO mice normally release ATP upon taste stimulation compared with wild type (WT) mice. Gustatory nerve recordings in response to various tastants applied to the tongue and brief-access behavioral testing with SC45647 also show no difference between Panx1 KO and WT. These results confirm that Panx1 is not required for the taste evoked release of ATP or for neural and behavioral responses to taste stimuli. PMID:26136251

  14. Propionibacterium acnes-induced hepatic granuloma formation is impaired in mice lacking tetraspanin CD9.

    PubMed

    Yamane, Hiroyuki; Tachibana, Isao; Takeda, Yoshito; Saito, Yoshiyuki; Tamura, Yoshio; He, Ping; Suzuki, Mayumi; Shima, Yoshihito; Yoneda, Tsutomu; Hoshino, Shigenori; Inoue, Koji; Kijima, Takashi; Yoshida, Mitsuhiro; Kumagai, Toru; Osaki, Tadashi; Eishi, Yoshinobu; Kawase, Ichiro

    2005-08-01

    The granuloma is a host defence response to persistent pathogenic irritants. In the process of granuloma formation, the activation, migration, and fusion of macrophages occur locally, but the mechanisms involved remain elusive. Tetraspanins regulate cell migration and fusion by organizing functional molecular complexes in membrane microdomains. Here we investigated the role of tetraspanin CD9 in hepatic granuloma formation. Immunostaining of the liver of untreated wild-type mice showed that CD9 was expressed by vascular endothelial cells and perivenular hepatocytes. When intrahepatic granulomas were induced by intravenous injection of Propionibacterium acnes, hepatocyte CD9 was extensively upregulated, while inflammatory cells constituting granulomas were mostly negative for CD9. Compared with wild-type littermates, CD9-knockout mice showed dissemination of Propionibacterium acnes and reduced number and size of granulomas after the injection. Moreover, production of granuloma-inducing cytokines, TNF-alpha and IFN-gamma, was delayed and chemotactic activity for macrophages was suppressed in the liver of mutant mice. These results suggest that CD9 is one of the proteins that promotes granuloma formation in the liver. Copyright 2005 Pathological Society of Great Britain and Ireland

  15. Mice Lacking Pannexin 1 Release ATP and Respond Normally to All Taste Qualities.

    PubMed

    Vandenbeuch, Aurelie; Anderson, Catherine B; Kinnamon, Sue C

    2015-09-01

    Adenosine triphosphate (ATP) is required for the transmission of all taste qualities from taste cells to afferent nerve fibers. ATP is released from Type II taste cells by a nonvesicular mechanism and activates purinergic receptors containing P2X2 and P2X3 on nerve fibers. Several ATP release channels are expressed in taste cells including CALHM1, Pannexin 1, Connexin 30, and Connexin 43, but whether all are involved in ATP release is not clear. We have used a global Pannexin 1 knock out (Panx1 KO) mouse in a series of in vitro and in vivo experiments. Our results confirm that Panx1 channels are absent in taste buds of the knockout mice and that other known ATP release channels are not upregulated. Using a luciferin/luciferase assay, we show that circumvallate taste buds from Panx1 KO mice normally release ATP upon taste stimulation compared with wild type (WT) mice. Gustatory nerve recordings in response to various tastants applied to the tongue and brief-access behavioral testing with SC45647 also show no difference between Panx1 KO and WT. These results confirm that Panx1 is not required for the taste evoked release of ATP or for neural and behavioral responses to taste stimuli.

  16. Autism-like socio-communicative deficits and stereotypies in mice lacking heparan sulfate

    PubMed Central

    Irie, Fumitoshi; Badie-Mahdavi, Hedieh; Yamaguchi, Yu

    2012-01-01

    Heparan sulfate regulates diverse cell-surface signaling events, and its roles in the development of the nervous system recently have been increasingly uncovered by studies using genetic models carrying mutations of genes encoding enzymes for its synthesis. On the other hand, the role of heparan sulfate in the physiological function of the adult brain has been poorly characterized, despite several pieces of evidence suggesting its role in the regulation of synaptic function. To address this issue, we eliminated heparan sulfate from postnatal neurons by conditionally inactivating Ext1, the gene encoding an enzyme essential for heparan sulfate synthesis. Resultant conditional mutant mice show no detectable morphological defects in the cytoarchitecture of the brain. Remarkably, these mutant mice recapitulate almost the full range of autistic symptoms, including impairments in social interaction, expression of stereotyped, repetitive behavior, and impairments in ultrasonic vocalization, as well as some associated features. Mapping of neuronal activation by c-Fos immunohistochemistry demonstrates that neuronal activation in response to social stimulation is attenuated in the amygdala in these mice. Electrophysiology in amygdala pyramidal neurons shows an attenuation of excitatory synaptic transmission, presumably because of the reduction in the level of synaptically localized AMPA-type glutamate receptors. Our results demonstrate that heparan sulfate is critical for normal functioning of glutamatergic synapses and that its deficiency mediates socio-communicative deficits and stereotypies characteristic for autism. PMID:22411800

  17. Multiple apoptotic defects in hematopoietic cells from mice lacking lipocalin 24p3.

    PubMed

    Liu, Zhuoming; Yang, Amy; Wang, Zhengqi; Bunting, Kevin D; Davuluri, Gangarao; Green, Michael R; Devireddy, Laxminarayana R

    2011-06-10

    The lipocalin mouse 24p3 has been implicated in diverse physiological processes, including apoptosis, iron trafficking, development and innate immunity. Studies from our laboratory as well as others demonstrated the proapoptotic activity of 24p3 in a variety of cultured models. However, a general role for the lipocalin 24p3 in the hematopoietic system has not been tested in vivo. To study the role of 24p3, we derived 24p3 null mice and back-crossed them onto C57BL/6 and 129/SVE backgrounds. Homozygous 24p3(-/-) mice developed a progressive accumulation of lymphoid, myeloid, and erythroid cells, which was not due to enhanced hematopoiesis because competitive repopulation and recovery from myelosuppression were the same as for wild type. Instead, apoptotic defects were unique to many mature hematopoietic cell types, including neutrophils, cytokine-dependent mast cells, thymocytes, and erythroid cells. Thymocytes isolated from 24p3 null mice also displayed resistance to apoptosis-induced by dexamethasone. Bim response to various apoptotic stimuli was attenuated in 24p3(-/-) cells, thus explaining their resistance to the ensuing cell death. The results of these studies, in conjunction with those of previous studies, reveal 24p3 as a regulator of the hematopoietic compartment with important roles in normal physiology and disease progression. Interestingly, these functions are limited to relatively mature blood cell compartments.

  18. Mice lacking ghrelin receptors resist the development of diet-induced obesity

    PubMed Central

    Zigman, Jeffrey M.; Nakano, Yoshihide; Coppari, Roberto; Balthasar, Nina; Marcus, Jacob N.; Lee, Charlotte E.; Jones, Juli E.; Deysher, Amy E.; Waxman, Amanda R.; White, Ryan D.; Williams, Todd D.; Lachey, Jennifer L.; Seeley, Randy J.; Lowell, Bradford B.; Elmquist, Joel K.

    2005-01-01

    Ghrelin is the endogenous ligand for the growth hormone secretagogue receptor (GHSR; ghrelin receptor). Since its discovery, accumulating evidence has suggested that ghrelin may play a role in signaling and reversing states of energy insufficiency. For example, ghrelin levels rise following food deprivation, and ghrelin administration stimulates feeding and increases body weight and adiposity. However, recent loss-of-function studies have raised questions regarding the physiological significance of ghrelin in regulating these processes. Here, we present results of a study using a novel GHSR-null mouse model, in which ghrelin administration fails to acutely stimulate food intake or activate arcuate nucleus neurons. We show that when fed a high-fat diet, both female and male GHSR-null mice eat less food, store less of their consumed calories, preferentially utilize fat as an energy substrate, and accumulate less body weight and adiposity than control mice. Similar effects on body weight and adiposity were also observed in female, but not male, GHSR-null mice fed standard chow. GHSR deletion also affected locomotor activity and levels of glycemia. These findings support the hypothesis that ghrelin-responsive pathways are an important component of coordinated body weight control. Moreover, our data suggest that ghrelin signaling is required for development of the full phenotype of diet-induced obesity. PMID:16322794

  19. The defects in development and apoptosis of cardiomyocytes in mice lacking the transcriptional factor Pax-8.

    PubMed

    Yang, Deye; Lai, Dandan; Huang, Xiaoyan; Shi, Xiangxiang; Gao, Zhan; Huang, Fang; Zhou, Xi; Geng, Yong-Jian

    2012-01-12

    Cardiac-specific deletion of ALK3 is lethal in mid-gestation with ventricular septum malformations (VSM). This study was designed to define the Pax-8's role in heart development and cardiomyocyte apoptosis. Pathologic changes in the hearts of Pax-8 or ALK3 knockout and wild type control mice were determined by light and electron microscopy. Analysis of cardiomyocyte apoptosis was performed by TUNEL. The effect of Pax-8 gene deficiency on caspase-3 activity was examined after transfecting Pax-8 siRNA into cultured myoblast cell line. Mice with ALK3 or Pax-8 gene knockout but not wild type control animals showed the development of VSM. Increased cardiomyocyte apoptosis was found in homozygotes. Echocardiography showed that Pax-8 homozygote mice developed malfunction of the heart. Furthermore, the caspase-3 activity was significantly higher in the cells treated with Pax-8 siRNA as compared to those treated with negative control siRNA in H9C2 (2-1) cell line. The Pax-8 gene may play a crucial role in heart development and regulating cardiocyte apoptosis. Knockout of Pax-8 may exert a similar effect on myocardial morphology and apoptosis as those seen in ALK3 knockouts. Furthermore, the ventricular septum malformations could be partially attributed to accelerated cardiomyocyte apoptosis. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  20. Effect of SQW on the bladder function of mice lacking TRPV1.

    PubMed

    Lai, Huanling; Yan, QiTao; Cao, Hongying; Chen, Pengyu; Xu, Yifei; Jiang, Weiwen; Wu, Qinghe; Huang, Ping; Tan, Bo

    2016-11-15

    Suo Quan Wan (SQW) is an effective traditional Chinese prescription on treated lower urinary tract symptoms (LUTS), and has been proved have modulation effect on the expression of transient receptor potential vanilloid 1 (TRPV1) in accordance with the recovery of bladder function of overactive bladder rat. This study further investigated the mechanism of SQW modulated TRPV1 signaling and bladder function using TRPV1 knockout (KO) mice. Study was conducted using wild type and TRPV1 KO mice. The KO animals were grouped into KO group and SQW treated group. We applied in vivo cystometrogram recording techniques to analyze voiding control of the urinary bladder, as well as in vitro organ bath to study bladder distension response to various compounds, which subsequently elicited normal smooth muscle excitation. Real-time polymerase chain reaction and western blot analysis were performed to quantify the expression of TRPV1 and P2X3 in the bladder. ATP released from bladder strips was measured using the luciferin-luciferase ATP bioluminescence assay kit. KO preparation inhibited decrease micturition times, while micturition interval and volume were increased. Results of urodynamic record of the TRPV1(-/-) mice during NS infusion showed reduced bladder pressure and contraction which exhibited decreased response to α, β-me ATP, KCl, and carbachol and no response to CAP. The ATP released by the TRPV1(-/-) mice from strips of bladder smooth muscles was significantly reduced, along with no TRPV1 expression and reduced expression level of P2X3 in the bladder. SQW could increase ATP release in some degree, while had no effect on TRPV1 and P2X3 expression. SQW could improve bladder pressure slightly, while make no significantly effects on the force response to α,β-meATP, CAP, carbachol in gradient concentration, and KCl, as well as MBC and voiding activities. TRPV1 plays an important role in urinary bladder mechanosensitivity. The effective SQW is hard to play its proper role

  1. Renal function and vasomotor activity in mice lacking the Cyp4a14 gene.

    PubMed

    Fidelis, Paul; Wilson, Leticia; Thomas, Kayama; Villalobos, Mayra; Oyekan, Adebayo O

    2010-11-01

    The production of 20-hydroxyeicosatetraenoic acid (20-HETE) in the kidney is thought to be involved in the control of renal vascular tone and tubular sodium and chloride reabsorption. Cytochrome (Cyp) P-450 enzymes of the Cyp4a family in the mouse, namely 4a10, -12 and 14, are involved in 20-HETE synthesis. Recent advances in the molecular genetics of the mouse have produced mice in which Cyp4a isoforms have been disrupted and the consequence of such an approach is examined. This study evaluated the effect of deletion of the Cyp4a14 gene on blood pressure, renal vascular responses and tubular function. When compared with the wild-type (WT) litter mates, systolic blood pressure was greater in Cyp4a14 null (KO) mice as were renal vascular responses to angiotensin II or phenyephrine, G protein-coupled receptor (GPCR) agonists, but not KCl, a non-GPCR agonist. Renal vascular responses to guanosine 5'-O-(gamma-thio)triphosphate, a non-hydrolyzable GTP analog, or NaF(4), an activator of G-proteins, were also enhanced. However, vasodilation to bradykinin or apocynin but not sodium nitroprusside was blunted in Cyp4a14 null (KO) kidneys. These changes in KO mice were accompanied by increased 20-HETE synthesis, reduced renal production of nitric oxide (NO), increased lipid hydroperoxides and increased apocynin-inhibitable vascular NADPH oxidase activity that was prevented by administration of NO synthase (NOS) inhibitor, suggesting endothelial nitric oxide synthase (eNOS) uncoupling. Cyp4a14 KO mice also exhibited a diminished capacity to excrete an acute sodium load (0.9% NaCl, 2.5 mL/kg). These data suggest that deletion of the Cyp4a gene conferred a prohypertensive status via mechanisms involving increased 20-HETE synthesis and eNOS uncoupling leading to increased oxidative stress, enhanced vasoconstriction but diminished vasodilation as well as a defect in the renal excretory capacity in Cyp4a14 KO mice. These mechanisms suggest that the Cyp4a14-deficient mouse may be a

  2. T-Cell Responses to Immunodominant LACK Antigen Do Not Play a Critical Role in Determining Susceptibility of BALB/c Mice to Leishmania mexicana

    PubMed Central

    Torrentera, Fabiola Aguilar; Glaichenhaus, Nicolas; Laman, Jon D.; Carlier, Yves

    2001-01-01

    Although BALB/c mice develop lesions when infected with Leishmania mexicana, the mechanisms which are responsible for susceptibility to this parasite have not been elucidated. In contrast, susceptibility of BALB/c mice to Leishmania major has been shown to depend on the early production of interleukin-4 (IL-4) by T cells which react to the parasitic LACK antigen. Here, we demonstrate that the lesions induced by L. mexicana are delayed compared to those induced by L. major but rapidly develop at later time points. Interestingly, while LACK-tolerant BALB/c-derived IE-LACK transgenic mice were resistant to L. major, they were susceptible to L. mexicana and developed lesions similar to those observed in wild-type BALB/c mice. The latter result was observed despite the fact that (i) LACK was expressed by L. mexicana, (ii) splenocytes from BALB/c mice were able to stimulate LACK-specific T-cell hybridoma cells when incubated with live L. mexicana promastigotes, and (iii) LACK-specific T cells contributed to IL-4 production in L. mexicana-infected BALB/c mice. Thus, in contrast to what was observed for L. major-infected mice, LACK-specific T cells do not play a critical role in determining susceptibility to L. mexicana. Although BALB/c mice are susceptible to both L. major and L. mexicana, the mechanisms which are responsible for susceptibility to these parasites are likely to be different. PMID:11119565

  3. A binding site for activation by the Bacillus subtilis AhrC protein, a repressor/activator of arginine metabolism.

    PubMed

    Klingel, U; Miller, C M; North, A K; Stockley, P G; Baumberg, S

    1995-08-21

    In Bacillus subtilis, the AhrC protein represses genes encoding enzymes of arginine biosynthesis and activates those mediating its catabolism. To determine how this repressor also functions as an activator, we attempted to clone catabolic genes by searching for insertions of the Tn917-lacZ transposon that express AhrC-dependent, arginine-inducible beta-galactosidase activity. One such isolate was obtained. The region upstream of lacZ was subcloned in Escherichia coli in such a way that it could be replaced in the B. subtilis chromosome after appropriate manipulation. Analysis of exonuclease III-derived deletions located an AhrC-dependent, arginine-inducible promoter to within a ca. 1.9 kb fragment. The sequence revealed: the 3' end of an ORF homologous to gdh genes encoding glutamate dehydrogenase, with highest homology to the homologue from Clostridium difficile; the 5' end of an ORF homologous to a Saccharomyces cerevisiae gene encoding delta 1-pyrroline 5-carboxylate dehydrogenase (P5CDH), an enzyme of arginine catabolism; and just upstream of the latter, a sequence with homology to known AhrC binding sites in the upstream part of the biosynthetic argCJBD-cpa-F cluster. The same region has also been sequenced by others as part of the B. subtilis genome sequencing project, revealing that the P5CDH gene is the first in a cluster termed rocABC. Restriction fragments containing the putative AhrC-binding sequence, but not those lacking it, showed retarded electrophoretic mobility in the presence of purified AhrC. A 277 bp AhrC-binding fragment also showed anomalous mobility in the absence of AhrC, consistent with its being intrinsically bent. DNAse I footprinting localized AhrC binding to bp -16/-22 to +1 (the transcription startpoint). Such a location for an activator binding site, i.e. overlapping the transcription start, is unusual.

  4. Alterations in Gene Expression in Mutant Amyloid Precursor Protein Transgenic Mice Lacking Niemann-Pick Type C1 Protein

    PubMed Central

    Maulik, Mahua; Thinakaran, Gopal; Kar, Satyabrata

    2013-01-01

    Niemann-Pick type C (NPC) disease, a rare autosomal recessive disorder caused mostly by mutation in NPC1 gene, is pathologically characterized by the accumulation of free cholesterol in brain and other tissues. This is accompanied by gliosis and loss of neurons in selected brain regions, including the cerebellum. Recent studies have shown that NPC disease exhibits intriguing parallels with Alzheimer’s disease, including the presence of neurofibrillary tangles and increased levels of amyloid precursor protein (APP)-derived β-amyloid (Aβ) peptides in vulnerable brain neurons. To evaluate the role of Aβ in NPC disease, we determined the gene expression profile in selected brain regions of our recently developed bigenic ANPC mice, generated by crossing APP transgenic (Tg) mice with heterozygous Npc1-deficient mice. The ANPC mice exhibited exacerbated neuronal and glial pathology compared to other genotypes [i.e., APP-Tg, double heterozygous (Dhet), Npc1-null and wild-type mice]. Analysis of expression profiles of 86 selected genes using real-time RT-PCR arrays showed a wide-spectrum of alterations in the four genotypes compared to wild-type controls. The changes observed in APP-Tg and Dhet mice are limited to only few genes involved mostly in the regulation of cholesterol metabolism, whereas Npc1-null and ANPC mice showed alterations in the expression profiles of a number of genes regulating cholesterol homeostasis, APP metabolism, vesicular trafficking and cell death mechanism in both hippocampus and cerebellum compared to wild-type mice. Intriguingly, ANPC and Npc1-null mice, with some exceptions, exhibited similar changes, although more genes were differentially expressed in the affected cerebellum than the relatively spared hippocampus. The altered gene profiles were found to match with the corresponding protein levels. These results suggest that lack of Npc1 protein can alter the expression profile of selected transcripts as well as proteins, and APP

  5. Antiseizure Activity of Midazolam in Mice Lacking δ-Subunit Extrasynaptic GABAA Receptors

    PubMed Central

    Reddy, Sandesh D.; Younus, Iyan; Clossen, Bryan L.

    2015-01-01

    Midazolam is a benzodiazepine anticonvulsant with rapid onset and short duration of action. Midazolam is the current drug of choice for acute seizures and status epilepticus, including those caused by organophosphate nerve agents. The antiseizure activity of midazolam is thought to result from its allosteric potentiation of synaptic GABAA receptors in the brain. However, there are indications that benzodiazepines promote neurosteroid synthesis via the 18-kDa cholesterol transporter protein (TSPO). Therefore, we investigated the role of neurosteroids and their extrasynaptic GABAA receptor targets in the antiseizure activity of midazolam. Here, we used δ-subunit knockout (DKO) mice bearing a targeted deletion of the extrasynaptic receptors to investigate the contribution of the extrasynaptic receptors to the antiseizure activity of midazolam using the 6-Hz and hippocampus kindling seizure models. In both models, midazolam produced rapid and dose-dependent protection against seizures (ED50, 0.4 mg/kg). Moreover, the antiseizure potency of midazolam was undiminished in DKO mice compared with control mice. Pretreatment with PK11195 [1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinolinecarboxamide], a TSPO blocker, or finasteride, a 5α-reductase neurosteroid inhibitor, did not affect the antiseizure effect of midazolam. The antiseizure activity of midazolam was significantly reversed by pretreatment with flumazenil, a benzodiazepine antagonist. Plasma and brain levels of the neurosteroid allopregnanolone were not significantly greater in midazolam-treated animals. These studies therefore provide strong evidence that neurosteroids and extrasynaptic GABAA receptors are not involved in the antiseizure activity of midazolam, which mainly occurs through synaptic GABAA receptors via direct binding to benzodiazepine sites. This study reaffirms midazolam’s use for controlling acute seizures and status epilepticus. PMID:25784648

  6. Fenofibrate unexpectedly induces cardiac hypertrophy in mice lacking MuRF1

    PubMed Central

    Schisler, Jonathan C.; Li, Luge; Quintana, Megan T.; Stanley, Natalie; Lockyer, Pamela; Patterson, Cam; Willis, Monte S.

    2015-01-01

    The muscle-specific ubiquitin ligase muscle ring finger-1 (MuRF1) is critical in regulating both pathological and physiological cardiac hypertrophy in vivo. Previous work from our group has identified MuRF1's ability to inhibit serum response factor and insulin-like growth factor-1 signaling pathways (via targeted inhibition of cJun as underlying mechanisms). More recently, we have identified that MuRF1 inhibits fatty acid metabolism by targeting peroxisome proliferator-activated receptor alpha (PPARα) for nuclear export via mono-ubiquitination. Since MuRF1−/− mice have an estimated fivefold increase in PPARα activity, we sought to determine how challenge with the PPARα agonist fenofibrate, a PPARα ligand, would affect the heart physiologically. In as little as 3 weeks, feeding with fenofibrate/chow (0.05% wt/wt) induced unexpected pathological cardiac hypertrophy not present in age-matched sibling wild-type (MuRF1 +/+) mice, identified by echocardiography, cardiomyocyte cross-sectional area, and increased beta-myosin heavy chain, brain natriuretic peptide, and skeletal muscle α-actin mRNA. In addition to pathological hypertrophy, MuRF1−/− mice had an unexpected differential expression in genes associated with the pleiotropic effects of fenofibrate involved in the extracellular matrix, protease inhibition, hemostasis, and the sarcomere. At both 3 and 8 weeks of fenofibrate treatment, the differentially expressed MuRF1−/− genes most commonly had SREBP-1 and E2F1/E2F promoter regions by TRANSFAC analysis (54 and 50 genes, respectively, of the 111 of the genes >4 and <−4 log fold change; P≤.0004). These studies identify MuRF1's unexpected regulation of fenofibrate's pleiotropic effects and bridges, for the first time, MuRF1's regulation of PPARα, cardiac hypertrophy, and hemostasis. PMID:26764147

  7. Pancreatic ductal adenocarcinoma mice lacking mucin 1 have a profound defect in tumor growth and metastasis.

    PubMed

    Besmer, Dahlia M; Curry, Jennifer M; Roy, Lopamudra D; Tinder, Teresa L; Sahraei, Mahnaz; Schettini, Jorge; Hwang, Sun-Il; Lee, Yong Y; Gendler, Sandra J; Mukherjee, Pinku

    2011-07-01

    MUC1 is overexpressed and aberrantly glycosylated in more than 60% of pancreatic ductal adenocarcinomas. The functional role of MUC1 in pancreatic cancer has yet to be fully elucidated due to a dearth of appropriate models. In this study, we have generated mouse models that spontaneously develop pancreatic ductal adenocarcinoma (KC), which are either Muc1-null (KCKO) or express human MUC1 (KCM). We show that KCKO mice have significantly slower tumor progression and rates of secondary metastasis, compared with both KC and KCM. Cell lines derived from KCKO tumors have significantly less tumorigenic capacity compared with cells from KCM tumors. Therefore, mice with KCKO tumors had a significant survival benefit compared with mice with KCM tumors. In vitro, KCKO cells have reduced proliferation and invasion and failed to respond to epidermal growth factor, platelet-derived growth factor, or matrix metalloproteinase 9. Further, significantly less KCKO cells entered the G(2)-M phase of the cell cycle compared with the KCM cells. Proteomics and Western blotting analysis revealed a complete loss of cdc-25c expression, phosphorylation of mitogen-activated protein kinase (MAPK), as well as a significant decrease in nestin and tubulin-α2 chain expression in KCKO cells. Treatment with a MEK1/2 inhibitor, U0126, abrogated the enhanced proliferation of the KCM cells but had minimal effect on KCKO cells, suggesting that MUC1 is necessary for MAPK activity and oncogenic signaling. This is the first study to utilize a Muc1-null PDA mouse to fully elucidate the oncogenic role of MUC1, both in vivo and in vitro. ©2011 AACR

  8. Impaired inflammatory and pain responses in mice lacking an inducible prostaglandin E synthase

    PubMed Central

    Trebino, Catherine E.; Stock, Jeffrey L.; Gibbons, Colleen P.; Naiman, Brian M.; Wachtmann, Timothy S.; Umland, John P.; Pandher, Karamjeet; Lapointe, Jean-Martin; Saha, Sipra; Roach, Marsha L.; Carter, Demetrius; Thomas, Nathalie A.; Durtschi, Becky A.; McNeish, John D.; Hambor, John E.; Jakobsson, Per-Johan; Carty, Thomas J.; Perez, Jose R.; Audoly, Laurent P.

    2003-01-01

    Prostaglandin (PG)E2 is a potent mediator of pain and inflammation, and high levels of this lipid mediator are observed in numerous disease states. The inhibition of PGE2 production to control pain and to treat diseases such as rheumatoid arthritis to date has depended on nonsteroidal antiinflammatory agents such as aspirin. However, these agents inhibit the synthesis of all prostanoids. To produce biologically active PGE2, PGE synthases catalyze the isomerization of PGH2 into PGE2. Recently, several PGE synthases have been identified and cloned, but their role in inflammation is not clear. To study the physiological role of the individual PGE synthases, we have generated by targeted homologous recombination a mouse line deficient in microsomal PGE synthase 1 (mPGES1) on the inbred DBA/1lacJ background. mPGES1-deficient (mPGES1-/-) mice are viable and fertile and develop normally compared with wild-type controls. However, mPGES1-/- mice displayed a marked reduction in inflammatory responses compared with mPGES1+/+ mice in multiple assays. Here, we identify mPGES1 as the PGE synthase that contributes to the pathogenesis of collagen-induced arthritis, a disease model of human rheumatoid arthritis. We also show that mPGES1 is responsible for the production of PGE2 that mediates acute pain during an inflammatory response. These findings suggest that mPGES1 provides a target for the treatment of inflammatory diseases and pain associated with inflammatory states. PMID:12835414

  9. Mice lacking brain-type creatine kinase activity show defective thermoregulation

    PubMed Central

    Streijger, Femke; Pluk, Helma; Oerlemans, Frank; Beckers, Gaby; Bianco, Antonio C.; Ribeiro, Miriam O.; Wieringa, Bé; Van der Zee, Catharina E.E.M.

    2010-01-01

    The cytosolic brain-type creatine kinase and mitochondrial ubiquitous creatine kinase (CK-B and UbCKmit) are expressed during the prepubescent and adult period of mammalian life. These creatine kinase (CK) isoforms are present in neural cell types throughout the central and peripheral nervous system and in smooth muscle containing tissues, where they have an important role in cellular energy homeostasis. Here, we report on the coupling of CK activity to body temperature rhythm and adaptive thermoregulation in mice. With both brain-type CK isoforms being absent, the body temperature reproducibly drops ~1.0°C below normal during every morning (inactive) period in the daily cycle. Facultative non-shivering thermogenesis is also impaired, since CK−−/−− mice develop severe hypothermia during 24 h cold exposure. A relationship with fat metabolism was suggested because comparison of CK−−/−− mice with wildtype controls revealed decreased weight gain associated with less white and brown fat accumulation and smaller brown adipocytes. Also, circulating levels of glucose, triglycerides and leptin are reduced. Extensive physiological testing and uncoupling protein1 analysis showed, however, that the thermogenic problems are not due to abnormal responsiveness of brown adipocytes, since noradrenaline infusion produced a normal increase of body temperature. Moreover, we demonstrate that the cyclic drop in morning temperature is also not related to altered rhythmicity with reduced locomotion, diminished food intake or increased torpor sensitivity. Although several integral functions appear altered when CK is absent in the brain, combined findings point into the direction of inefficient neuronal transmission as the dominant factor in the thermoregulatory defect. PMID:19419668

  10. Fenofibrate unexpectedly induces cardiac hypertrophy in mice lacking MuRF1.

    PubMed

    Parry, Traci L; Desai, Gopal; Schisler, Jonathan C; Li, Luge; Quintana, Megan T; Stanley, Natalie; Lockyer, Pamela; Patterson, Cam; Willis, Monte S

    2016-01-01

    The muscle-specific ubiquitin ligase muscle ring finger-1 (MuRF1) is critical in regulating both pathological and physiological cardiac hypertrophy in vivo. Previous work from our group has identified MuRF1's ability to inhibit serum response factor and insulin-like growth factor-1 signaling pathways (via targeted inhibition of cJun as underlying mechanisms). More recently, we have identified that MuRF1 inhibits fatty acid metabolism by targeting peroxisome proliferator-activated receptor alpha (PPARα) for nuclear export via mono-ubiquitination. Since MuRF1-/- mice have an estimated fivefold increase in PPARα activity, we sought to determine how challenge with the PPARα agonist fenofibrate, a PPARα ligand, would affect the heart physiologically. In as little as 3 weeks, feeding with fenofibrate/chow (0.05% wt/wt) induced unexpected pathological cardiac hypertrophy not present in age-matched sibling wild-type (MuRF1+/+) mice, identified by echocardiography, cardiomyocyte cross-sectional area, and increased beta-myosin heavy chain, brain natriuretic peptide, and skeletal muscle α-actin mRNA. In addition to pathological hypertrophy, MuRF1-/- mice had an unexpected differential expression in genes associated with the pleiotropic effects of fenofibrate involved in the extracellular matrix, protease inhibition, hemostasis, and the sarcomere. At both 3 and 8 weeks of fenofibrate treatment, the differentially expressed MuRF1-/- genes most commonly had SREBP-1 and E2F1/E2F promoter regions by TRANSFAC analysis (54 and 50 genes, respectively, of the 111 of the genes >4 and <-4 log fold change; P ≤ .0004). These studies identify MuRF1's unexpected regulation of fenofibrate's pleiotropic effects and bridges, for the first time, MuRF1's regulation of PPARα, cardiac hypertrophy, and hemostasis. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Hypoalgesia and altered inflammatory responses in mice lacking kinin B1 receptors.

    PubMed

    Pesquero, J B; Araujo, R C; Heppenstall, P A; Stucky, C L; Silva, J A; Walther, T; Oliveira, S M; Pesquero, J L; Paiva, A C; Calixto, J B; Lewin, G R; Bader, M

    2000-07-05

    Kinins are important mediators in cardiovascular homeostasis, inflammation, and nociception. Two kinin receptors have been described, B1 and B2. The B2 receptor is constitutively expressed, and its targeted disruption leads to salt-sensitive hypertension and altered nociception. The B1 receptor is a heptahelical receptor distinct from the B2 receptor in that it is highly inducible by inflammatory mediators such as bacterial lipopolysaccharide and interleukins. To clarify its physiological function, we have generated mice with a targeted deletion of the gene for the B1 receptor. B1 receptor-deficient animals are healthy, fertile, and normotensive. In these mice, bacterial lipopolysaccharide-induced hypotension is blunted, and there is a reduced accumulation of polymorphonuclear leukocytes in inflamed tissue. Moreover, under normal noninflamed conditions, they are analgesic in behavioral tests of chemical and thermal nociception. Using whole-cell patch-clamp recordings, we show that the B1 receptor was not necessary for regulating the noxious heat sensitivity of isolated nociceptors. However, by using an in vitro preparation, we could show that functional B1 receptors are present in the spinal cord, and their activation can facilitate a nociceptive reflex. Furthermore, in B1 receptor-deficient mice, we observed a reduction in the activity-dependent facilitation (wind-up) of a nociceptive spinal reflex. Thus, the kinin B1 receptor plays an essential physiological role in the initiation of inflammatory responses and the modulation of spinal cord plasticity that underlies the central component of pain. The B1 receptor therefore represents a useful pharmacological target especially for the treatment of inflammatory disorders and pain.

  12. Aberrant Inflammatory Response to Streptococcus pyogenes in Mice Lacking Myeloid Differentiation Factor 88

    PubMed Central

    Loof, Torsten G.; Goldmann, Oliver; Gessner, André; Herwald, Heiko; Medina, Eva

    2010-01-01

    Several in vitro studies have emphasized the importance of toll-like receptor/myeloid differentiation factor 88 (MyD88) signaling in the inflammatory response to Streptococcus pyogenes. Since the extent of inflammation has been implicated in the severity of streptococcal diseases, we have examined here the role of toll-like receptor/MyD88 signaling in the pathophysiology of experimental S. pyogenes infection. To this end, we compared the response of MyD88-knockout (MyD88−/−) after subcutaneous inoculation with S. pyogenes with that of C57BL/6 mice. Our results show that MyD88−/− mice harbored significantly more bacteria in the organs and succumbed to infection much earlier than C57BL/6 animals. Absence of MyD88 resulted in diminished production of inflammatory cytokines such as interleukin-12, interferon-γ, and tumor necrosis factor-α as well as chemoattractants such as monocyte chemotactic protein-1 (MCP-1) and Keratinocyte-derived chemokine (KC), and hampered recruitment of effector cells involved in bacterial clearance (macrophages and neutrophils) to the infection site. Furthermore, MyD88−/− but not C57BL/6 mice exhibited a massive infiltration of eosinophils in infected organs, which can be explained by an impaired production of the regulatory chemokines, gamma interferon-induced monokine (MIG/CXCL9) and interferon-induced protein 10 (IP-10/CXCL10), which can inhibit transmigration of eosinophils. Our results indicate that MyD88 signaling targets effector cells to the site of streptococcal infection and prevents extravasation of cells that can induce tissue damage. Therefore, MyD88 signaling may be important for shaping the quality of the inflammatory response elicited during infection to ensure optimal effector functions. PMID:20019195

  13. Superoxide Mediates Acute Liver Injury in Irradiated Mice Lacking Sirtuin 3

    PubMed Central

    Coleman, Mitchell C.; Olivier, Alicia K.; Jacobus, James A.; Mapuskar, Kranti A.; Mao, Gaowei; Martin, Sean M.; Riley, Dennis P.; Gius, David

    2014-01-01

    Abstract Aims: This study determined whether acute radiation-induced liver injury seen in Sirtuin3−/− mice after exposure to Cs-137 γ-rays was mediated by superoxide anion (O2•−). Results: Male wild-type (WT) and SIRT3−/− mice were given 2×2 Gy whole-body radiation doses separated by 24 h and livers were harvested 20 h after the second dose. Ex vivo measurements in fresh frozen liver sections demonstrated 50% increases in dihydroethidium oxidation from SIRT3−/− animals, relative to WT animals, before irradiation, but this increase was not detected 20 h after radiation exposure. In addition, irradiated livers from SIRT3−/− animals showed significant hydropic degeneration, loss of MitoTracker Green FM staining, increased immunohistochemical staining for 3-nitrotyrosine, loss of Ki67 staining, and increased mitochondrial localization of p53. These parameters of radiation-induced injury were significantly attenuated by an intraperitoneal injection of 2 mg/kg of the highly specific superoxide dismutase mimic, GC4401, 30 min before each fraction. Innovation: Sirtuin 3 (SIRT3) is believed to regulate mitochondrial oxidative metabolism and antioxidant defenses in response to acute radiation-induced liver injury. This work provides strong evidence for the causal role of O2•− in the liver injury process initiated by whole-body irradiation in SIRT3−/− mice. Conclusion: These results support the hypothesis that O2•− mediates acute liver injury in SIRT3−/− animals exposed to whole-body γ-radiation and suggest that GC4401 could be used as a radio-protective compound in vivo. Antioxid. Redox Signal. 20, 1423–1435. PMID:23919724

  14. Generation of mice lacking DUF1220 protein domains: effects on fecundity and hyperactivity.

    PubMed

    Keeney, J G; O'Bleness, M S; Anderson, N; Davis, J M; Arevalo, N; Busquet, N; Chick, W; Rozman, J; Hölter, S M; Garrett, L; Horsch, M; Beckers, J; Wurst, W; Klingenspor, M; Restrepo, D; de Angelis, M Hrabě; Sikela, J M

    2015-02-01

    Sequences encoding DUF1220 protein domains show the most extreme human lineage-specific copy number increase of any coding region in the genome and have been linked to human brain evolution. In addition, DUF1220 copy number (dosage) has been implicated in influencing brain size within the human species, both in normal populations and in individuals associated with brain size pathologies (1q21-associated microcephaly and macrocephaly). More recently, increasing dosage of a subtype of DUF1220 has been linked with increasing severity of the primary symptoms of autism. Despite these intriguing associations, a function for these domains has not been described. As a first step in addressing this question, we have developed the first transgenic model of DUF1220 function by removing the single DUF1220 domain (the ancestral form) encoded in the mouse genome. In a hypothesis generating exercise, these mice were evaluated by 197 different phenotype measurements. While resulting DUF1220-minus (KO) mice show no obvious anatomical peculiarities, they exhibit a significantly reduced fecundity (χ(2) = 19.1, df = 2, p = 7.0 × 10(-5)). Further extensive phenotypic analyses suggest hyperactivity (p < 0.05) of DUF1220 mice and changes in gene expression levels of brain associated with distinct neurological functions and disease. Other changes that met statistical significance include an increase in plasma glucose concentration (as measured by area under the curve, AUC 0-30 and AUC 30-120) in male mutants, fasting glucose levels, reduce sodium levels in male mutants, increased levels of the liver functional indicator ALAT/GPT in males, levels of alkaline phosphatase (also an indicator of liver function), mean R and SR amplitude by electrocardiography, elevated IgG3 levels, a reduced ratio of CD4:CD8 cells, and a reduced frequency of T cells; though it should be noted that many of these differences are quite small and require further examination. The linking of DUF1220 loss to a

  15. Generation of mice lacking DUF1220 protein domains: effects on fecundity and hyperactivity

    PubMed Central

    Keeney, JG; O’Bleness, MS; Anderson, N; Davis, JM; Arevalo, N; Busquet, N; Chick, W; Rozman, J; Hölter, SM; Garrett, L; Horsch, M; Beckers, J; Wurst, W; Klingenspor, M; Restrepo, D

    2014-01-01

    Sequences encoding DUF1220 protein domains show the most extreme human lineage-specific copy number increase of any coding region in the genome and have been linked to human brain evolution. In addition, DUF1220 copy number (dosage) has been implicated in influencing brain size within the human species, both in normal populations and in individuals associated with brain size pathologies (1q21-associated microcephaly and macrocephaly). More recently, increasing dosage of a subtype of DUF1220 has been linked with increasing severity of the primary symptoms of autism. Despite these intriguing associations, a function for these domains has not been described. As a first step in addressing this question we have developed the first transgenic model of DUF1220 function by removing the single DUF1220 domain (the ancestral form) encoded in the mouse genome. In a hypothesis generating exercise, these mice were evaluated by 197 different phenotype measurements. While resulting DUF1220-minus (KO) mice show no obvious anatomical peculiarities, they exhibit a significantly reduced fecundity (χ2= 19.1, df = 2, p = 7.0 × 10−5). Further extensive phenotypic analyses suggest hyperactivity (p < 0.05) of DUF1220 mice and changes in gene expression levels of brain associated with distinct neurological functions and disease. Other changes that met statistical significance include an increase in plasma glucose concentration (as measured by Area Under the Curve, AUC 0-30 and AUC 30-120) in male mutants, fasting glucose levels, reduce sodium levels in male mutants, increased levels of the liver functional indicator ALAT/GPT in males, levels of alkaline phosphatase (also an indicator of liver function), mean R and SR amplitude by electrocardiography, elevated IgG3 levels, a reduced ratio of CD4:CD8 cells, and a reduced frequency of T cells; though it should be noted that many of these differences are quite small and require further examination. The linking of DUF1220 loss to a

  16. Deficit in attachment behavior in mice lacking the mu-opioid receptor gene.

    PubMed

    Moles, Anna; Kieffer, Brigitte L; D'Amato, Francesca R

    2004-06-25

    Endogenous opioid binding to micro receptors is hypothesized to mediate natural rewards and has been proposed to be the basis of infant attachment behavior. Here, we report that micro-opioid receptor knockout mouse pups emit fewer ultrasonic vocalizations when removed from their mothers but not when exposed to cold or male mice odors. Moreover these knockout pups do not show a preference toward their mothers' cues and do not show ultrasonic calls potentiation after brief maternal exposure. Results from this study may indicate a molecular mechanism for diseases characterized by deficits in attachment behavior, such as autism or reactive attachment disorder.

  17. A maternal Ahr null genotype sensitizes embryos to chemical teratogenesis.

    PubMed

    Thomae, Tami L; Glover, Edward; Bradfield, Christopher A

    2004-07-16

    The aryl hydrocarbon receptor (encoded by the Ahr locus) is a ligand-activated transcription factor that mediates the toxicology and teratology of 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin). In an effort to understand the role of the maternal compartment in dioxin teratology, we designed a breeding strategy that allowed us to compare the teratogenic response in embryos from Ahr(-/-) (null) and Ahr(+/+) (wild-type) dams. Using this strategy, we demonstrate that embryos from the Ahr(-/-) dams are 5-fold more sensitive to dioxin-induced cleft palate and hydronephrosis as compared with embryos from an Ahr(+/+) dam. Moreover, this increased teratogenic sensitivity extends beyond dioxin, because embryos from Ahr(-/-) dams exhibited a 9-fold increase in their sensitivity to the fetotoxic effects of the glucocorticoid, dexamethasone. In searching for an explanation for this increased sensitivity, we found that more dioxin and dexamethasone reached the embryos from Ahr(-/-) dams as compared with embryos from Ahr(+/+) dams. We propose that increased deposition of teratogens/fetotoxicants to the embryonic compartment is the result of porto-systemic shunting and/or blocked P4501A induction in Ahr(-/-) dams. In addition to demonstrating the importance of maternal AHR in teratogenesis, these data may have implications that reach beyond the mechanism of action of dioxin. In this regard, the Ahr(-/-) mouse may provide a system that allows pharmacological agents and toxicants to be more easily studied in a model where first pass clearance is a significant obstacle.

  18. Impaired humoral immunity and tolerance in K14-VEGFR-3-Ig mice that lack dermal lymphatic drainage

    PubMed Central

    Thomas, Susan N.; Rutkowski, Joseph M.; Pasquier, Miriella; Kuan, Emma L.; Alitalo, Kari; Randolph, Gwendalyn J.; Swartz, Melody A.

    2012-01-01

    Lymphatic vessels transport interstitial fluid, soluble antigen, and immune cells from peripheral tissues to lymph nodes (LNs), yet the contribution of peripheral lymphatic drainage to adaptive immunity remains poorly understood. We examined immune responses to dermal vaccination and contact hypersensitivity (CHS) challenge in K14-VEGFR-3-Ig mice, which lack dermal lymphatic capillaries and experience markedly depressed transport of solutes and dendritic cells from the skin to draining LNs. In response to dermal immunization, K14-VEGFR-3-Ig mice produced lower antibody titers. In contrast, although delayed, T cell responses were robust after 21 days, including high levels of antigen-specific CD8+ T cells and production of IFN-γ, IL-4 and IL-10 upon restimulation. T cell-mediated CHS responses were strong in K14-VEGFR-3-Ig mice, but importantly, their ability to induce CHS tolerance in the skin was impaired. Additionally, one-year-old mice displayed multiple signs of autoimmunity. These data suggest that lymphatic drainage plays more important roles in regulating humoral immunity and peripheral tolerance than in effector T cell immunity. PMID:22844119

  19. Mice lacking GPR3 receptors display late-onset obese phenotype due to impaired thermogenic function in brown adipose tissue

    PubMed Central

    Godlewski, Grzegorz; Jourdan, Tony; Szanda, Gergő; Tam, Joseph; Resat Cinar; Harvey-White, Judith; Liu, Jie; Mukhopadhyay, Bani; Pacher, Pál; Ming Mo, Fong; Osei-Hyiaman, Douglas; George Kunos

    2015-01-01

    We report an unexpected link between aging, thermogenesis and weight gain via the orphan G protein-coupled receptor GPR3. Mice lacking GPR3 and maintained on normal chow had similar body weights during their first 5 months of life, but gained considerably more weight thereafter and displayed reduced total energy expenditure and lower core body temperature. By the age of 5 months GPR3 KO mice already had lower thermogenic gene expression and uncoupling protein 1 protein level and showed impaired glucose uptake into interscapular brown adipose tissue (iBAT) relative to WT littermates. These molecular deviations in iBAT of GPR3 KO mice preceded measurable differences in body weight and core body temperature at ambient conditions, but were coupled to a failure to maintain thermal homeostasis during acute cold challenge. At the same time, the same cold challenge caused a 17-fold increase in Gpr3 expression in iBAT of WT mice. Thus, GPR3 appears to have a key role in the thermogenic response of iBAT and may represent a new therapeutic target in age-related obesity. PMID:26455425

  20. Increased contribution of L-arginine-nitric oxide pathway in aorta of mice lacking the gene for vimentin.

    PubMed

    Zhang, J; Henrion, D; Ebrahimian, T; Benessiano, J; Colucci-Guyon, E; Langa, F; Lévy, B I; Boulanger, C M

    2001-10-01

    Experiments were designed to investigate endothelial function in the aorta of mice lacking the gene for the cytoskeleton protein vimentin (vim -/- ). Rings with and without endothelium from wild-type (vim +/+ ), heterozygous (vim +/- ), and homozygous (vim -/- ) mice were suspended in organ chambers to record of changes in isometric tension. During phenylephrine contraction, acetylcholine evoked comparable endothelium-dependent relaxations in the three groups. In the presence of Nomega-nitro-L-arginine, acetylcholine caused endothelium-dependent contractions, which were greater in vim -/- than in vim +/+ and vim +/- aortas. Indomethacin did not affect relaxation to acetylcholine in vim +/+ or in vim +/-, but it significantly increased the maximal response in vim -/- (67 +/- 7 vs. 102 +/- 4%). Response to acetylcholine in vim -/- aortas was not affected by cyclooxygenase type 2 inhibitor NS-398, the thromboxane receptor antagonist SQ-29,548, or superoxide dismutase. Relaxations to sodium nitroprusside were not different between vim +/+ and vim -/- mice and were not affected by cyclooxygenase inhibition. Cyclic guanosine monophosphate levels, which were increased to a comparable level by acetylcholine in vim +/+ and vim -/-, were augmented by indomethacin in vim -/- aortas but not in vim +/+ aortas. Expression of endothelial nitric oxide synthase was not different between vim +/+ and vim -/- preparations. These results suggest that despite comparable endothelium-dependent responses to acetylcholine, endothelial cells from vim -/- mice release a cyclooxygenase product that compensates the augmented contribution of nitric oxide.

  1. Mice Lacking the ITIM-Containing Receptor G6b-B Exhibit Macrothrombocytopenia and Aberrant Platelet Function

    PubMed Central

    Mori, Jun; Bem, Danai; Finney, Brenda; Heising, Silke; Gissen, Paul; White, James G.; Berndt, Michael C.; Gardiner, Elizabeth E.; Nieswandt, Bernhard; Douglas, Michael R.; Campbell, Robert D.; Watson, Steve P.; Senis, Yotis A.

    2013-01-01

    Platelets are highly reactive cell fragments that adhere to exposed extracellular matrix (ECM) and prevent excessive blood loss by forming clots. Paradoxically, megakaryocytes, which produce platelets in the bone marrow, remain relatively refractory to the ECM-rich environment of the bone marrow despite having the same repertoire of receptors as platelets. These include the ITAM (immunoreceptor tyrosine–based activation motif)–containing collagen receptor complex, which consists of glycoprotein VI (GPVI) and the Fc receptor γ-chain, and the ITIM (immunoreceptor tyrosine–based inhibition motif)–containing receptor G6b-B. We showed that mice lacking G6b-B exhibited macrothrombocytopenia (reduced platelet numbers and the presence of enlarged platelets) and a susceptibility to bleeding as a result of aberrant platelet production and function. Platelet numbers were markedly reduced in G6b-B–deficient mice compared to those in wild-type mice because of increased platelet turnover. Furthermore, megakaryocytes in G6b-B–deficient mice showed enhanced metalloproteinase production, which led to increased shedding of cell-surface receptors, including GPVI and GPIba. In addition, G6b-B–deficient megakaryocytes exhibited reduced integrin-mediated functions and defective formation of proplatelets, the long filamentous projections from which platelets bud off. Together, these findings establish G6b-B as a major inhibitory receptor regulating megakaryocyte activation, function, and platelet production. PMID:23112346

  2. Severe myopathy in mice lacking the MEF2/SRF-dependent gene leiomodin-3

    PubMed Central

    Cenik, Bercin K.; Garg, Ankit; McAnally, John R.; Shelton, John M.; Richardson, James A.; Bassel-Duby, Rhonda; Olson, Eric N.; Liu, Ning

    2015-01-01

    Maintenance of skeletal muscle structure and function requires a precise stoichiometry of sarcomeric proteins for proper assembly of the contractile apparatus. Absence of components of the sarcomeric thin filaments causes nemaline myopathy, a lethal congenital muscle disorder associated with aberrant myofiber structure and contractility. Previously, we reported that deficiency of the kelch-like family member 40 (KLHL40) in mice results in nemaline myopathy and destabilization of leiomodin-3 (LMOD3). LMOD3 belongs to a family of tropomodulin-related proteins that promote actin nucleation. Here, we show that deficiency of LMOD3 in mice causes nemaline myopathy. In skeletal muscle, transcription of Lmod3 was controlled by the transcription factors SRF and MEF2. Myocardin-related transcription factors (MRTFs), which function as SRF coactivators, serve as sensors of actin polymerization and are sequestered in the cytoplasm by actin monomers. Conversely, conditions that favor actin polymerization de-repress MRTFs and activate SRF-dependent genes. We demonstrated that the actin nucleator LMOD3, together with its stabilizing partner KLHL40, enhances MRTF-SRF activity. In turn, SRF cooperated with MEF2 to sustain the expression of LMOD3 and other components of the contractile apparatus, thereby establishing a regulatory circuit to maintain skeletal muscle function. These findings provide insight into the molecular basis of the sarcomere assembly and muscle dysfunction associated with nemaline myopathy. PMID:25774500

  3. Mice lacking microRNA 133a develop dynamin 2–dependent centronuclear myopathy

    PubMed Central

    Liu, Ning; Bezprozvannaya, Svetlana; Shelton, John M.; Frisard, Madlyn I.; Hulver, Matthew W.; McMillan, Ryan P.; Wu, Yaru; Voelker, Kevin A.; Grange, Robert W.; Richardson, James A.; Bassel-Duby, Rhonda; Olson, Eric N.

    2011-01-01

    MicroRNAs modulate cellular phenotypes by inhibiting expression of mRNA targets. In this study, we have shown that the muscle-specific microRNAs miR-133a-1 and miR-133a-2 are essential for multiple facets of skeletal muscle function and homeostasis in mice. Mice with genetic deletions of miR-133a-1 and miR-133a-2 developed adult-onset centronuclear myopathy in type II (fast-twitch) myofibers, accompanied by impaired mitochondrial function, fast-to-slow myofiber conversion, and disarray of muscle triads (sites of excitation-contraction coupling). These abnormalities mimicked human centronuclear myopathies and could be ascribed, at least in part, to dysregulation of the miR-133a target mRNA that encodes dynamin 2, a GTPase implicated in human centronuclear myopathy. Our findings reveal an essential role for miR-133a in the maintenance of adult skeletal muscle structure, function, bioenergetics, and myofiber identity; they also identify a potential modulator of centronuclear myopathies. PMID:21737882

  4. Mice Lacking Alkbh1 Display Sex-Ratio Distortion and Unilateral Eye Defects

    PubMed Central

    Nordstrand, Line M.; Lien, Guro F.; Rognes, Torbjørn; Namekawa, Satoshi H.; Lee, Jeannie T.; Klungland, Arne

    2010-01-01

    Background Eschericia coli AlkB is a 2-oxoglutarate- and iron-dependent dioxygenase that reverses alkylated DNA damage by oxidative demethylation. Mouse AlkB homolog 1 (Alkbh1) is one of eight members of the newly discovered family of mammalian dioxygenases. Methods and Findings In the present study we show non-Mendelian inheritance of the Alkbh1 targeted allele in mice. Both Alkbh1−/− and heterozygous Alkbh1+/− offspring are born at a greatly reduced frequency. Additionally, the sex-ratio is considerably skewed against female offspring, with one female born for every three to four males. Most mechanisms that cause segregation distortion, act in the male gametes and affect male fertility. The skewing of the sexes appears to be of paternal origin, and might be set in the pachythene stage of meiosis during spermatogenesis, in which Alkbh1 is upregulated more than 10-fold. In testes, apoptotic spermatids were revealed in 5–10% of the tubules in Alkbh1−/− adults. The deficiency of Alkbh1 also causes misexpression of Bmp2, 4 and 7 at E11.5 during embryonic development. This is consistent with the incompletely penetrant phenotypes observed, particularly recurrent unilateral eye defects and craniofacial malformations. Conclusions Genetic and phenotypic assessment suggests that Alkbh1 mediates gene regulation in spermatogenesis, and that Alkbh1 is essential for normal sex-ratio distribution and embryonic development in mice. PMID:21072209

  5. Abdominal Distension and Escherichia coli Peritonitis in Mice Lacking Myeloid Differentiation Factor 88.

    PubMed

    Johnson, Linda K; Widi, Antin Yn; Rowarth, Serrin; Baxter, Alan G

    2015-04-01

    Here we describe the gross and microscopic findings of naturally occurring, β-hemolytic Escherichia coli peritonitis in B6.129-Myd88(tm1Aki) male and female mice. Over approximately 5 mo, 10 homozygous mutant mice deficient in myeloid differentiation factor 88 (C57BL/6 strain; male and female) that had not been used in research protocols developed rapid-onset abdominal swelling associated with copious viscous ascites. Each mouse developed an anterior peritonitis, primarily involving the parietal peritoneum and the visceral surface of the spleen, liver, diaphragm, and stomach. Inflammation was confined to the organ surfaces, with no indication of septicemia or grossly apparent gastrointestinal perforation or other tissue compromise that would initiate peritonitis. Peritonitis was likely attributable to compromised antibacterial innate immunity; cohoused, similarly immunodeficient littermates did not develop similar clinical signs. An unusual finding in all cases was mesothelial cell hyperplasia and hypertrophy. Although the underlying innate immune deficiency accounts for much of the observed pathology, the remarkable mesothelial cell morphology and the episodic nature of the peritonitis in some littermates and not others remain unexplained.

  6. Lack of behavioral and neuropathological effects of dietary beta-methylamino-L-alanine (BMAA) in mice.

    PubMed

    Cruz-Aguado, Reyniel; Winkler, Daniella; Shaw, Christopher A

    2006-06-01

    Beta-methylamino-L-alanine (BMAA) is an excitotoxin allegedly involved in ALS-parkinsonism-dementia complex (ALS-PDC), a neurological disorder found in Guam and its surrounding islands, in which motor neuron disease symptoms can present alone or can co-occur with parkinsonism and dementia. Although in vitro experiments have shown BMAA's neurotoxic properties, studies using adult animals and systemic administration which better model the case of environmentally-induced human neurodegenerative diseases have not supported the involvement of BMAA in these disorders. In order to better test the hypothesized role of BMAA in neurodegeneration, we fed adult mice BMAA at a dose (28 mg/kg body weight, daily for 30 days) that reproduces the natural levels and tested the animals with a battery of behavioural tests, the latter including the evaluation of motor coordination, motor neuron-mediated reflexes, locomotion, muscular strength and memory. We also assessed whether BMAA exposure triggers cell death in the central nervous system (CNS) of mice by examining neuronal numbers and glial response in the spinal cord and the brain. No motor, cognitive or neuropathological outcome resulted from this feeding paradigm. Our findings support neither the causal role of BMAA in neurodegeneration nor the specific involvement of this amino acid in ALS-PDC.

  7. Learning and memory deficits in mice lacking protease activated receptor-1.

    PubMed

    Almonte, Antoine G; Hamill, Cecily E; Chhatwal, Jasmeer P; Wingo, Thomas S; Barber, Jeremy A; Lyuboslavsky, Polina N; David Sweatt, J; Ressler, Kerry J; White, David A; Traynelis, Stephen F

    2007-10-01

    The roles of serine proteases and protease activated receptors have been extensively studied in coagulation, wound healing, inflammation, and neurodegeneration. More recently, serine proteases have been suggested to influence synaptic plasticity. In this context, we examined the role of protease activated receptor 1 (PAR1), which is activated following proteolytic cleavage by thrombin and plasmin, in emotionally motivated learning. We were particularly interested in PAR1 because its activation enhances the function of NMDA receptors, which are required for some forms of synaptic plasticity. We examined several baseline behavioral measures, including locomotor activity, expression of anxiety-like behavior, motor task acquisition, nociceptive responses, and startle responses in C57Bl/6 mice in which the PAR1 receptor has been genetically deleted. In addition, we evaluated learning and memory in these mice using two memory tasks, passive avoidance and cued fear-conditioning. Whereas locomotion, pain response, startle, and measures of baseline anxiety were largely unaffected by PAR1 removal, PAR1-/- animals showed significant deficits in a passive avoidance task and in cued fear conditioning. These data suggest that PAR1 may play an important role in emotionally motivated learning.

  8. Impaired motor coordination and Purkinje cell excitability in mice lacking calretinin

    PubMed Central

    Schiffmann, Serge N.; Cheron, Guy; Lohof, Ann; d’Alcantara, Pablo; Meyer, Michael; Parmentier, Marc; Schurmans, Stéphane

    1999-01-01

    In the cerebellum, the parallel fiber-Purkinje cell synapse can undergo long-term synaptic plasticity suggested to underlie motor learning and resulting from variations in intracellular calcium concentration ([Ca2+]i). Ca2+ binding proteins are enriched in the cerebellum, but their role in information processing is not clear. Here, we show that mice deficient in calretinin (Cr−/−) are impaired in tests of motor coordination. An impairment in Ca2+ homeostasis in Cr−/− Purkinje cells was supported by the high Ca2+-saturation of calbindin-D28k in these cells. The firing behavior of Purkinje cells is severely affected in Cr−/− alert mice, with alterations of simple spike firing rate, complex spike duration, and simple spike pause. In contrast, in slices, transmission at parallel fiber- or climbing fiber-Purkinje cell synapses is unaltered, indicating that marked modifications of the firing behavior in vivo can be undetectable in slice. Thus, these results show that calretinin plays a major role at the network level in cerebellar physiology. PMID:10220453

  9. Mice lacking JunB are osteopenic due to cell-autonomous osteoblast and osteoclast defects.

    PubMed

    Kenner, Lukas; Hoebertz, Astrid; Beil, F Timo; Beil, Timo; Keon, Niamh; Karreth, Florian; Eferl, Robert; Scheuch, Harald; Szremska, Agnieszka; Amling, Michael; Schorpp-Kistner, Marina; Angel, Peter; Wagner, Erwin F

    2004-02-16

    Because JunB is an essential gene for placentation, it was conditionally deleted in the embryo proper. JunBDelta/Delta mice are born viable, but develop severe low turnover osteopenia caused by apparent cell-autonomous osteoblast and osteoclast defects before a chronic myeloid leukemia-like disease. Although JunB was reported to be a negative regulator of cell proliferation, junBDelta/Delta osteoclast precursors and osteoblasts show reduced proliferation along with a differentiation defect in vivo and in vitro. Mutant osteoblasts express elevated p16(INK4a) levels, but exhibit decreased cyclin D1 and cyclin A expression. Runx2 is transiently increased during osteoblast differentiation in vitro, whereas mature osteoblast markers such as osteocalcin and bone sialoprotein are strongly reduced. To support a cell-autonomous function of JunB in osteoclasts, junB was inactivated specifically in the macrophage-osteoclast lineage. Mutant mice develop an osteopetrosis-like phenotype with increased bone mass and reduced numbers of osteoclasts. Thus, these data reveal a novel function of JunB as a positive regulator controlling primarily osteoblast as well as osteoclast activity.

  10. Reduced chondrocyte proliferation and chondrodysplasia in mice lacking the integrin-linked kinase in chondrocytes

    PubMed Central

    Terpstra, Leonieke; Prud'homme, Josée; Arabian, Alice; Takeda, Shu; Karsenty, Gérard; Dedhar, Shoukat; St-Arnaud, René

    2003-01-01

    Chondrocyte proliferation and differentiation requires their attachment to the collagen type II–rich matrix of developing bone. This interaction is mediated by integrins and their cytoplasmic effectors, such as the integrin-linked kinase (ILK). To elucidate the molecular mechanisms whereby integrins control these processes, we have specifically inactivated the ILK gene in growth plate chondrocytes using the Cre-lox methodology. Mice carrying an ILK allele flanked by loxP sites (ILK-fl) were crossed to transgenic mice expressing the Cre recombinase under the control of the collagen type II promoter. Inactivation of both copies of the ILK-fl allele lead to a chondrodysplasia characterized by a disorganized growth plate and to dwarfism. Expression of chondrocyte differentiation markers such as collagen type II, collagen type X, Indian hedgehog and the PTH-PTHrP receptor was normal in ILK-deficient growth plates. In contrast, chondrocyte proliferation, assessed by BrdU or proliferating cell nuclear antigen labeling, was markedly reduced in the mutant growth plates. Cell-based assays showed that integrin-mediated adhesion of primary cultures of chondrocytes from mutant animals to collagen type II was impaired. ILK inactivation in chondrocytes resulted in reduced cyclin D1 expression, and this most likely explains the defect in chondrocyte proliferation observed when ILK is inactivated in growth plate cells. PMID:12835312

  11. ASTROGLIOSIS AND BEHAVIORAL CHANGES IN MICE LACKING THE NEUTRAL CYSTEINE PROTEASE BLEOMYCIN HYDROLASE

    PubMed Central

    Montoya, S.E.; Thiels, E.; Card, J.P.; Lazo, J.S.

    2007-01-01

    Bleomycin hydrolase is a multifaceted neutral cysteine protease with a suggested role in antigen presentation, homocysteine-thiolactone metabolism, and Alzheimer’s disease pathogenesis. Deletion of the protease in mice results in increased neonatal mortality and dermatopathology. Immunohistochemical and behavioral studies of BLMH knockout mice were undertaken to further evaluate the role of the protease in the brain. No gross abnormalities in the central nervous system were observed upon preliminary histological examination of B6.129Blmhtm1Geh/J null animals. However, glial fibrillary acid protein immunohistochemistry revealed a global reactive astrogliosis in the aged null animals, indicative of undefined brain pathology. The role of BLMH in the brain was further explored by characterizing the behavioral phenotype of hybrid [129S6-Blmhtm1Geh/J X B6.129 Blmhtm1Geh/J]F1 null and littermate controls using multiple behavioral paradigms. In the water maze, deletion of BLMH resulted in poorer performance during water maze probe trials without detectable effect of the mutation on sensorimotor function. In addition, no age-dependent decline in discriminative performance on probe trials was observed in null animals. These data suggest a physiological non-redundant function for BLMH in the central nervous system. PMID:17391860

  12. Trace fear conditioning is enhanced in mice lacking the δ subunit of the GABAA receptor

    PubMed Central

    Wiltgen, Brian J.; Sanders, Matthew J.; Ferguson, Carolyn; Homanics, Gregg E.; Fanselow, Michael S.

    2005-01-01

    The δ subunit of the GABAA receptor (GABAAR) is highly expressed in the dentate gyrus of the hippocampus. Genetic deletion of this subunit reduces synaptic and extrasynaptic inhibition and decreases sensitivity to neurosteroids. This paper examines the effect of these changes on hippocampus-dependent trace fear conditioning. Compared to controls, δ knockout mice exhibited enhanced acquisition of tone and context fear. Hippocampus-independent delay conditioning was normal in these animals. These results suggest that reduced inhibition in the dentate gyrus facilitates the acquisition of trace fear conditioning. However, the enhancement in trace conditioning was only observed in female knockout mice. The sex-specificity of this effect may be a result of neuroactive steroids. These compounds vary during the estrus cycle, can increase GABAergic inhibition, and have been shown to impair hippocampus-dependent learning. We propose that activation of GABAARs by neuroactive steroids inhibits learning processes in the hippocampus. Knockouts are immune to this effect because of the reduced neurosteroid sensitivity that accompanies deletion of the δ subunit. Relationships between neurosteroids, hippocampal excitability, and memory are discussed. PMID:15897254

  13. Learning and memory deficits in mice lacking protease activated receptor-1

    PubMed Central

    Almonte, Antoine G.; Hamill, Cecily E.; Chhatwal, Jasmeer P.; Wingo, Thomas S.; Barber, Jeremy A.; Lyuboslavsky, Polina N.; Sweatt, J. David; Ressler, Kerry J.; White, David A.; Traynelis, Stephen F.

    2007-01-01

    The roles of serine proteases and protease activated receptors have been extensively studied in coagulation, wound healing, inflammation, and neurodegeneration. More recently, serine proteases have been suggested to influence synaptic plasticity. In this context, we examined the role of protease activated receptor 1 (PAR1), which is activated following proteolytic cleavage by thrombin and plasmin, in emotionally-motivated learning. We were particularly interested in PAR1 because its activation enhances the function of NMDA receptors, which are required for some forms of synaptic plasticity. We examined several baseline behavioral measures, including locomotor activity, expression of anxiety-like behavior, motor task acquisition, nociceptive responses, and startle responses in C57Bl/6 mice in which the PAR1 receptor has been genetically deleted. In addition, we evaluated learning and memory in these mice using two memory tasks, passive avoidance and cued fear-conditioning. Whereas locomotion, pain response, startle, and measures of baseline anxiety were largely unaffected by PAR1 removal, PAR1−/− animals showed significant deficits in a passive avoidance task and in cued fear conditioning. These data suggest that PAR1 may play an important role in emotionally-motivated learning. PMID:17544303

  14. Impaired neuromuscular transmission and skeletal muscle fiber necrosis in mice lacking Na/Ca exchanger 3

    PubMed Central

    Sokolow, Sophie; Manto, Mario; Gailly, Philippe; Molgó, Jordi; Vandebrouck, Clarisse; Vanderwinden, Jean-Marie; Herchuelz, Andre; Schurmans, Stéphane

    2004-01-01

    We produced and analyzed mice deficient for Na/Ca exchanger 3 (NCX3), a protein that mediates cellular Ca2+ efflux (forward mode) or Ca2+ influx (reverse mode) and thus controls intracellular Ca2+ concentration. NCX3-deficient mice (Ncx3–/–) present a skeletal muscle fiber necrosis and a defective neuromuscular transmission, reflecting the absence of NCX3 in the sarcolemma of the muscle fibers and at the neuromuscular junction. The defective neuromuscular transmission is characterized by the presence of electromyographic abnormalities, including low compound muscle action potential amplitude, a decremental response at low-frequency nerve stimulation, an incremental response, and a prominent postexercise facilitation at high-frequency nerve stimulation, as well as neuromuscular blocks. The analysis of quantal transmitter release in Ncx3–/– neuromuscular junctions revealed an important facilitation superimposed on the depression of synaptic responses and an elevated delayed release during high-frequency nerve stimulation. It is suggested that Ca2+ entering nerve terminals is cleared relatively slowly in the absence of NCX3, thereby enhancing residual Ca2+ and evoked and delayed quantal transmitter release during repetitive nerve stimulation. Our findings indicate that NCX3 plays an important role in vivo in the control of Ca2+ concentrations in the skeletal muscle fibers and at the neuromuscular junction. PMID:14722618

  15. Lack of Tryptophan Hydroxylase-1 in Mice Results in Gait Abnormalities

    PubMed Central

    Suidan, Georgette L.; Vanderhorst, Veronique; Hampton, Thomas G.; Wong, Siu Ling; Voorhees, Jaymie R.; Wagner, Denisa D.

    2013-01-01

    The role of peripheral serotonin in nervous system development is poorly understood. Tryptophan hydroxylase-1 (TPH1) is expressed by non-neuronal cells including enterochromaffin cells of the gut, mast cells and the pineal gland and is the rate-limiting enzyme involved in the biosynthesis of peripheral serotonin. Serotonin released into circulation is taken up by platelets via the serotonin transporter and stored in dense granules. It has been previously reported that mouse embryos removed from Tph1-deficient mothers present abnormal nervous system morphology. The goal of this study was to assess whether Tph1-deficiency results in behavioral abnormalities. We did not find any differences between Tph1-deficient and wild-type mice in general motor behavior as tested by rotarod, grip-strength test, open field and beam walk. However, here we report that Tph1 (−/−) mice display altered gait dynamics and deficits in rearing behavior compared to wild-type (WT) suggesting that tryptophan hydroxylase-1 expression has an impact on the nervous system. PMID:23516593

  16. Immune modulation and lack of alloimmunization following transfusion with pathogen-reduced platelets in mice.

    PubMed

    Jackman, Rachael P; Muench, Marcus O; Heitman, John W; Inglis, Heather C; Law, Jacqueline P; Marschner, Susanne; Goodrich, Raymond P; Norris, Philip J

    2013-11-01

    Transfusion of allogeneic blood products can lead to alloimmunization, impacting success of subsequent transfusions and solid organ transplants. Pathogen reduction using riboflavin and ultraviolet B (UVB) light has been shown to eliminate the immunogenicity of white blood cells (WBCs) in vitro through down regulation of surface adhesion molecules, effectively blocking cell-cell conjugation and direct presentation. We sought to determine if this loss of immunogenicity is extended in vivo where indirect presentation of allogeneic antigens can occur. BALB/cJ mice were transfused with either untreated or riboflavin and UVB-treated C57Bl/6J platelet-rich plasma (PRP) containing WBCs. Circulating alloantibody and allospecific splenocyte cytokine responses were measured. Pathogen reduction of allogeneic WBC-enriched PRP using riboflavin and UVB light before transfusion prevented alloimmunization, with a loss of both alloantibody generation and priming of secondary cytokine responses ex vivo. When mice given treated transfusions were subsequently given untreated transfusions, they produced normal levels of alloantibodies but had reduced secondary cytokine responses ex vivo. This immune modulation was antigen specific and was dependent on the presence of WBCs in the treated product. UVB plus riboflavin treatment of WBC-enriched PRP effectively blocks alloimmunization and modulates immune responses to subsequent exposures. © 2013 American Association of Blood Banks.

  17. Alterations of cortical pyramidal neurons in mice lacking high-affinity nicotinic receptors

    PubMed Central

    Ballesteros-Yáñez, Inmaculada; Benavides-Piccione, Ruth; Bourgeois, Jean-Pierre; Changeux, Jean-Pierre; DeFelipe, Javier

    2010-01-01

    The neuronal nicotinic acetylcholine receptors (nAChRs) are allosteric membrane proteins involved in multiple cognitive processes, including attention, learning, and memory. The most abundant form of heterooligomeric nAChRs in the brain contains the β2- and α4- subunits and binds nicotinic agonists with high affinity. In the present study, we investigated in the mouse the consequences of the deletion of one of the nAChR components: the β2-subunit (β2−/−) on the microanatomy of cortical pyramidal cells. Using an intracellular injection method, complete basal dendritic arbors of 650 layer III pyramidal neurons were sampled from seven cortical fields, including primary sensory, motor, and associational areas, in both β2−/− and WT animals. We observed that the pyramidal cell phenotype shows significant quantitative differences among different cortical areas in mutant and WT mice. In WT mice, the density of dendritic spines was rather similar in all cortical fields, except in the prelimbic/infralimbic cortex, where it was significantly higher. In the absence of the β2-subunit, the most significant reduction in the density of spines took place in this high-order associational field. Our data suggest that the β2-subunit is involved in the dendritic morphogenesis of pyramidal neurons and, in particular, in the circuits that contribute to the high-order functional connectivity of the cerebral cortex. PMID:20534523

  18. Pyrene-induced CYP1A2 and SULT1A1 may be regulated by CAR and not by AhR.

    PubMed

    Lee, Chul-Ho; Ito, Yuki; Yanagiba, Yukie; Yamanoshita, Osamu; Kim, Heon; Zhang, Shu-Yun; Kamijima, Michihiro; Gonzalez, Frank J; Nakajima, Tamie

    2007-09-05

    Aryl hydrocarbon receptor (AhR) plays important roles in the regulation and induction of xenobiotic-metabolizing enzymes including the cytochromes P450 1 family (CYP1) and UDP-glucuronosyltransferases 1A (UGT1As) by polycyclic aromatic hydrocarbons as well as chlorinated aromatic hydrocarbons. To determine whether pyrene-induced xenobiotic-metabolizing enzymes are regulated by AhR, male AhR (+/+) and (-/-) mice were used. Both genotyped mice were exposed to 0, 205, 300 or 410 mg/(kgday pyrene), once daily, for four consecutive days by gavage. Exposure to pyrene did not influence hepatic CYP1A1-mRNA in mice of both genotypes, whereas it induced hepatic CYP1A2 protein and mRNA expression and associated 7-ethoxyresorufin O-deethylase and pyrene 1-hydroxylation activities in both AhR (+/+) and (-/-) mice. Similar effects were also found with sulfotransferase 1A1 expression and the associated 1-hydroxypyrene sulfation activity. In contrast, pyrene exposure increased expression of the UGT1A1 and 1A6, and glucuronidation activities associated with 1-hydroxypyrene and 1-naphthol in the liver only in AhR (-/-) mice, although pyrene treatment dose-dependently decreased the latter activity. Pyrene exposure did not increase AhR-mRNA expression in AhR (+/+) mice. In contrast, pyrene-induced expression of the hepatic constitutive androstane receptor (CAR) and one of its target genes, CYP2B10, in both AhR (+/+) and (-/-) mice. These results strongly suggest that pyrene-induced CYP1A2 and SULT1A1 are regulated by CAR, not by AhR. However, the mechanisms of UGT1A1 and 1A6 induction by pyrene were not elucidated in this study.

  19. Transcriptional Factor Aryl Hydrocarbon Receptor (Ahr) Controls Cardiovascular and Respiratory Functions by Regulating the Expression of the Vav3 Proto-oncogene*

    PubMed Central

    Sauzeau, Vincent; Carvajal-González, José M.; Riolobos, Adelaida S.; Sevilla, María A.; Menacho-Márquez, Mauricio; Román, Ángel C.; Abad, Antonio; Montero, María J.; Fernández-Salguero, Pedro; Bustelo, Xosé R.

    2011-01-01

    Aryl hydrocarbon receptor (Ahr) is a transcriptional factor involved in detoxification responses to pollutants and in intrinsic biological processes of multicellular organisms. We recently described that Vav3, an activator of Rho/Rac GTPases, is an Ahr transcriptional target in embryonic fibroblasts. These results prompted us to compare the Ahr−/− and Vav3−/− mouse phenotypes to investigate the implications of this functional interaction in vivo. Here, we show that Ahr is important for Vav3 expression in kidney, lung, heart, liver, and brainstem regions. This process is not affected by the administration of potent Ahr ligands such as benzo[a]pyrene. We also report that Ahr- and Vav3-deficient mice display hypertension, tachypnea, and sympathoexcitation. The Ahr gene deficiency also induces the GABAergic transmission defects present in the Vav3−/− ventrolateral medulla, a main cardiorespiratory brainstem center. However, Ahr−/− mice, unlike Vav3-deficient animals, display additional defects in fertility, perinatal growth, liver size and function, closure, spleen size, and peripheral lymphocytes. These results demonstrate that Vav3 is a bona fide Ahr target that is in charge of a limited subset of the developmental and physiological functions controlled by this transcriptional factor. Our data also reveal the presence of sympathoexcitation and new cardiorespiratory defects in Ahr−/− mice. PMID:21115475

  20. Behavioral and Cerebellar Transmission Deficits in Mice Lacking the Autism-Linked Gene Islet Brain-2

    PubMed Central

    Giza, Joanna; Urbanski, Michael J.; Prestori, Francesca; Bandyopadhyay, Bhaswati; Yam, Annie; Friedrich, Victor; Kelley, Kevin; D'Angelo, Egidio; Goldfarb, Mitchell

    2010-01-01

    Deletion of the human SHANK3 gene near the terminus of chromosome 22q is associated with Phelan-McDermid syndrome and autism spectrum disorders. Nearly all such deletions also span the tightly linked IB2 gene. We show here that IB2 protein is broadly expressed in the brain and is highly enriched within postsynaptic densities. Experimental disruption of the IB2 gene in mice reduces AMPA and enhances NMDA receptor-mediated glutamatergic transmission in cerebellum, changes the morphology of Purkinje cell dendritic arbors, and induces motor and cognitive deficits suggesting an autism phenotype. These findings support a role for human IB2 mutation as a contributing genetic factor in Chr22qter-associated cognitive disorders. PMID:21048139

  1. Defective Dendrite Elongation but Normal Fertility in Mice Lacking the Rho-Like GTPase Activator Dbl

    PubMed Central

    Hirsch, Emilio; Pozzato, Michela; Vercelli, Alessandro; Barberis, Laura; Azzolino, Ornella; Russo, Chiara; Vanni, Cristina; Silengo, Lorenzo; Eva, Alessandra; Altruda, Fiorella

    2002-01-01

    Dbl is the prototype of a large family of GDP-GTP exchange factors for small GTPases of the Rho family. In vitro, Dbl is known to activate Rho and Cdc42 and to induce a transformed phenotype. Dbl is specifically expressed in brain and gonads, but its in vivo functions are largely unknown. To assess its role in neurogenesis and gametogenesis, targeted deletion of the murine Dbl gene was accomplished in embryonic stem cells. Dbl-null mice are viable and did not show either decreased reproductive performances or obvious neurological defects. Histological analysis of mutant testis showed normal morphology and unaltered proliferation and survival of spermatogonia. Dbl-null brains indicated a correct disposition of the major neural structures. Analysis of cortical stratification indicated that Dbl is not crucial for neuronal migration. However, in distinct populations of Dbl-null cortical pyramidal neurons, the length of dendrites was significantly reduced, suggesting a role for Dbl in dendrite elongation. PMID:11940671

  2. Excess α-synuclein worsens disease in mice lacking ubiquitin carboxy-terminal hydrolase L1.

    PubMed

    Shimshek, Derya R; Schweizer, Tatjana; Schmid, Peter; van der Putten, P Herman

    2012-01-01

    Mutations in α-synuclein (αSN) and ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) have been linked to familial Parkinson's disease (PD). Physical and functional interactions between these two proteins have been described. Whether they act additively in vivo to influence disease has remained controversial. αSN is a presynaptic protein and the major constituent of Lewy inclusions, histopathological hallmarks of PD. UCH-L1 regulates ubiquitin stability in the nervous system and its loss results in neurodegeneration in peripheral and central neurons. Here, we used genetics to show that UCH-L1-deficiency together with excess αSN worsen disease. Double mutant mice show earlier-onset motor deficits, a shorter lifespan and forebrain astrogliosis but the additive disease-worsening effects of UCH-L1-deficiency and excess αSN are not accompanied by microgliosis, ubiquitin pathology or changes in pathological αSN protein levels and species.

  3. Abnormal Cerebellar Cytoarchitecture and Impaired Inhibitory Signaling in Adult Mice Lacking Testicular Orphan Nuclear Receptor 4

    PubMed Central

    Chen, Yei-Tsung; Collins, Loretta L.; Uno, Hideo; Chou, Samuel M.; Meshul, Charles K.; Chang, Shu-Shi; Chang, Chawnshang

    2007-01-01

    Since Testicular orphan nuclear receptor 4 (TR4) was cloned, its physiological functions remain largely unknown. In this study, the TR4 knockout (TR4−/−) mouse model was used to investigate the role of TR4 in the adult cerebellum. Behaviorally, these null mice exhibit unsteady gait, as well as involuntary postural and kinetic movements, indicating a disturbance of cerebellar function. In the TR4−/− brain, cerebellar restricted hypoplasia is severe and cerebellar vermal lobules VI and VII are underdeveloped, while no structural alterations in the cerebral cortex are observed. Histological analysis of the TR4−/− cerebellar cortex reveals reductions in granule cell density, as well as a decreased number of parallel fiber boutons that are enlarged in size. Further analyses reveal that the levels of GABA and GAD are decreased in both Purkinje cells and interneurons of the TR4−/− cerebellum, suggesting that the inhibitory circuits signaling within and from the cerebellum may be perturbed. In addition, in the TR4−/− cerebellum, immunoreactivity of GluR2/3 was reduced in Purkinje cells, but increased in the deep cerebellar nuclei. Together, these results suggest that the behavioral phenotype of TR4−/− mice may result from disrupted inhibitory pathways in the cerebellum. No progressive atrophy was observed at various adult stages in the TR4−/− brain, therefore the disturbances most likely originate from a failure to establish proper connections between principal neurons in the cerebellum during development. PMID:17706948

  4. Progressive deafness and altered cochlear innervation in knock-out mice lacking prosaposin.

    PubMed

    Akil, Omar; Chang, Jolie; Hiel, Hakim; Kong, Jee-Hyun; Yi, Eunyoung; Glowatzki, Elisabeth; Lustig, Lawrence R

    2006-12-13

    After a yeast two-hybrid screen identified prosaposin as a potential interacting protein with the nicotinic acetylcholine receptor (nAChR) subunit alpha10, studies were performed to characterize prosaposin in the normal rodent inner ear. Prosaposin demonstrates diffuse organ of Corti expression at birth, with gradual localization to the inner hair cells (IHCs) and its supporting cells, inner pillar cells, and synaptic region of the outer hair cells (OHCs) and Deiters' cells (DCs) by postnatal day 21 (P21). Microdissected OHC and DC quantitative reverse transcriptase-PCR and immunohistology localizes prosaposin mRNA to DCs and OHCs, and protein predominantly to the apex of the DCs. Subsequent studies in a prosaposin knock-out (KO) (-/-) mouse showed intact but slightly reduced hearing through P19, but deafness by P25 and reduced distortion product otoacoustic emissions from P15 onward. Beginning at P12, the prosaposin KO mice showed histologic organ of Corti changes including cellular hypertrophy in the region of the IHC and greater epithelial ridge, a loss of OHCs from cochlear apex, and vacuolization of OHCs. Immunofluorescence revealed exuberant overgrowth of auditory afferent neurites in the region of the IHCs and proliferation of auditory efferent neurites in the region of the tunnel of Corti. IHC recordings from these KO mice showed normal I-V curves and responses to applied acetylcholine. Together, these results suggest that prosaposin helps maintain normal innervation patterns to the organ of Corti. Furthermore, prosaposin's overlapping developmental expression pattern and binding capacity toward the nAChR alpha10 suggest that alpha10 may also play a role in this function.

  5. Retinal waves in mice lacking the beta2 subunit of the nicotinic acetylcholine receptor.

    PubMed

    Sun, Chao; Warland, David K; Ballesteros, Jose M; van der List, Deborah; Chalupa, Leo M

    2008-09-09

    The structural and functional properties of the visual system are disrupted in mutant animals lacking the beta2 subunit of the nicotinic acetylcholine receptor. In particular, eye-specific retinogeniculate projections do not develop normally in these mutants. It is widely thought that the developing retinas of beta2(-/-) mutants do not manifest correlated activity, leading to the notion that retinal waves play an instructional role in the formation of eye-specific retinogeniculate projections. By multielectrode array recordings, we show here that the beta2(-/-) mutants have robust retinal waves during the formation of eye-specific projections. Unlike in WT animals, however, the mutant retinal waves are propagated by gap junctions rather than cholinergic circuitry. These results indicate that lack of retinal waves cannot account for the abnormalities that have been documented in the retinogeniculate pathway of the beta2(-/-) mutants and suggest that other factors must contribute to the deficits in the visual system that have been noted in these animals.

  6. Lack of adrenoleukodystrophy protein enhances oligodendrocyte disturbance and microglia activation in mice with combined Abcd1/Mag deficiency.

    PubMed

    Dumser, Martina; Bauer, Jan; Lassmann, Hans; Berger, Johannes; Forss-Petter, Sonja

    2007-12-01

    X-linked adrenoleukodystrophy (X-ALD) is an inherited neurometabolic disease associated with the accumulation of very long-chain fatty acids. Mutations in the ABCD1 gene encoding ALD protein (ALDP) cause this clinically heterogeneous disorder, ranging from adrenocortical insufficiency and neurodegeneration to severe cerebral inflammation and demyelination. ALDP-deficient mice replicate metabolic dysfunctions and develop late-onset axonopathy but lack histological signs of cerebral inflammation and demyelination. To test the hypothesis that subtle destabilization of myelin may initiate inflammatory demyelination in Abcd1 deficiency, we generated mice with the combined metabolic defect of X-ALD and the mild myelin abnormalities of myelin-associated glycoprotein (MAG) deficiency. A behavioural phenotype, impaired motor performance and tremor, developed in middle-aged Mag null mice, independent of Abcd1 genotype. Routine histology revealed no signs of inflammation or demyelination in the CNS, but immunohistochemical analyses of spinal cord neuropathology revealed microglia activation and axonal degeneration in Mag and Abcd1/Mag double-knockout (ko) and, less severe and of later onset, in Abcd1 mutants. While combined Abcd1/Mag deficiency showed an additive effect on microglia activation, axonal degeneration, quantified by accumulation of amyloid precursor protein (APP) in axonal spheroids, was not accelerated. Interestingly, abnormal APP reactivity was enhanced within compact myelin of Abcd1/Mag double-ko mice compared to single mutants already at 13 months. These results suggest that ALDP deficiency enhances metabolic distress in oligodendrocytes that are compromised a priori by destabilised myelin. Furthermore, the age at which this occurs precedes by far the onset of axonal degeneration in Abcd1-deficient mice, implying that oligodendrocyte/myelin disturbances may precede axonopathy in X-ALD.

  7. Impaired hippocampal-dependent learning and functional abnormalities in the hippocampus in mice lacking serotonin1A receptors

    PubMed Central

    Sarnyai, Zoltán; Sibille, Etienne L.; Pavlides, Constantine; Fenster, Robert J.; McEwen, Bruce S.; Tóth, Miklós

    2000-01-01

    The hippocampus is a major limbic target of the brainstem serotonergic neurons that modulate fear, anxiety, and learning through postsynaptic serotonin1A receptors (5-HT1A receptors). Because chronic stress selectively down-regulates the 5-HT1A receptors in the hippocampus, we hypothesized that mice lacking these receptors may exhibit abnormalities reminiscent of symptoms of stress-related psychiatric disorders. In particular, a hippocampal deficit in the 5-HT1A receptor could contribute to the cognitive abnormalities often seen in these disorders. To test whether a deficit in 5-HT1A receptors impairs hippocampus-related functions, we studied hippocampal-dependent learning and memory, synaptic plasticity in the hippocampus, and limbic neuronal excitability in 5-HT1A-knockout (KO) mice. 5-HT1A-KO animals showed a deficit in hippocampal-dependent learning and memory tests, such as the hidden platform (spatial) version of the Morris water maze and the delayed version of the Y maze. The performance of KO mice was not impaired in nonhippocampal memory tasks such as the visible platform (nonspatial) version of the Morris water maze, the immediate version of the Y maze, and the spontaneous-alternation test of working memory. Furthermore, paired-pulse facilitation in the dentate gyrus of the hippocampus was impaired in 5-HT1A-KO mice. Finally, 5-HT1A-KO mice, as compared with wild-type animals, displayed higher limbic excitability manifested as lower seizure threshold and higher lethality in response to kainic acid administration. These results demonstrate that 5-HT1A receptors are required for maintaining normal hippocampal functions and implicate a role for the 5-HT1A receptor in hippocampal-related symptoms, such as cognitive disturbances, in stress-related disorders. PMID:11121072

  8. Ablating the aryl hydrocarbon receptor (AhR) in CD11c+ cells perturbs intestinal epithelium development and intestinal immunity.

    PubMed

    Chng, Song Hui; Kundu, Parag; Dominguez-Brauer, Carmen; Teo, Wei Ling; Kawajiri, Kaname; Fujii-Kuriyama, Yoshiaki; Mak, Tak Wah; Pettersson, Sven

    2016-04-12

    Diet and microbiome derived indole derivatives are known to activate the ligand induced transcription factor, the Aryl hydrocarbon Receptor (AhR). While the current understanding of AhR biology has confirmed its role in mucosal lymphocytes, its function in intestinal antigen presenting cells (APCs) is poorly understood. Here, we report that Cre-mediated deletion of AhR in CD11c-expressing cells in C57/BL6 mice is associated with altered intestinal epithelial morphogenesis in vivo. Moreover, when co-cultured with AhR-deficient DCs ex vivo, intestinal organoids showed reduced SRY (sex determining region Y)-box 9 and increased Mucin 2 expression, which correlates with reduced Paneth cells and increased goblet cell differentiation, similar to the data obtained in vivo. Further, characterization of intestinal APC subsets, devoid of AhR, revealed an expression pattern associated with aberrant intrinsic Wnt pathway regulation. At a functional level, the loss of AhR in APCs resulted in a dysfunctional epithelial barrier, associated with a more aggressive chemically induced colitis compared to wild type animals. Our results are consistent with a model whereby the AhR signalling pathway may participate in the regulation of innate immunity through intestinal epithelium development and mucosal immunity.

  9. Xenobiotic Metabolism in Mice Lacking the UDP-Glucuronosyltransferase 2 Family

    PubMed Central

    Fay, Matthew J.; Nguyen, My Trang; Snouwaert, John N.; Dye, Rebecca; Grant, Delores J.; Bodnar, Wanda M.

    2015-01-01

    UDP-Glucuronosyltransferases (UGTs) conjugate a glucuronyl group from glucuronic acid to a wide range of lipophilic substrates to form a hydrophilic glucuronide conjugate. The glucuronide generally has decreased bioactivity and increased water solubility to facilitate excretion. Glucuronidation represents an important detoxification pathway for both endogenous waste products and xenobiotics, including drugs and harmful industrial chemicals. Two clinically significant families of UGT enzymes are present in mammals: UGT1s and UGT2s. Although the two families are distinct in gene structure, studies using recombinant enzymes have shown considerable overlap in their ability to glucuronidate many substrates, often obscuring the relative importance of the two families in the clearance of particular substrates in vivo. To address this limitation, we have generated a mouse line, termed ΔUgt2, in which the entire Ugt2 gene family, extending over 609 kilobase pairs, is excised. This mouse line provides a means to determine the contributions of the two UGT families in vivo. We demonstrate the utility of these animals by defining for the first time the in vivo contributions of the UGT1 and UGT2 families to glucuronidation of the environmental estrogenic agent bisphenol A (BPA). The highest activity toward this chemical is reported for human and rodent UGT2 enzymes. Surprisingly, our studies using the ΔUgt2 mice demonstrate that, while both UGT1 and UGT2 isoforms can conjugate BPA, clearance is largely dependent on UGT1s. PMID:26354949

  10. Autistic-like behaviours and hyperactivity in mice lacking ProSAP1/Shank2.

    PubMed

    Schmeisser, Michael J; Ey, Elodie; Wegener, Stephanie; Bockmann, Juergen; Stempel, A Vanessa; Kuebler, Angelika; Janssen, Anna-Lena; Udvardi, Patrick T; Shiban, Ehab; Spilker, Christina; Balschun, Detlef; Skryabin, Boris V; Dieck, Susanne tom; Smalla, Karl-Heinz; Montag, Dirk; Leblond, Claire S; Faure, Philippe; Torquet, Nicolas; Le Sourd, Anne-Marie; Toro, Roberto; Grabrucker, Andreas M; Shoichet, Sarah A; Schmitz, Dietmar; Kreutz, Michael R; Bourgeron, Thomas; Gundelfinger, Eckart D; Boeckers, Tobias M

    2012-04-29

    Autism spectrum disorders comprise a range of neurodevelopmental disorders characterized by deficits in social interaction and communication, and by repetitive behaviour. Mutations in synaptic proteins such as neuroligins, neurexins, GKAPs/SAPAPs and ProSAPs/Shanks were identified in patients with autism spectrum disorder, but the causative mechanisms remain largely unknown. ProSAPs/Shanks build large homo- and heteromeric protein complexes at excitatory synapses and organize the complex protein machinery of the postsynaptic density in a laminar fashion. Here we demonstrate that genetic deletion of ProSAP1/Shank2 results in an early, brain-region-specific upregulation of ionotropic glutamate receptors at the synapse and increased levels of ProSAP2/Shank3. Moreover, ProSAP1/Shank2(-/-) mutants exhibit fewer dendritic spines and show reduced basal synaptic transmission, a reduced frequency of miniature excitatory postsynaptic currents and enhanced N-methyl-d-aspartate receptor-mediated excitatory currents at the physiological level. Mutants are extremely hyperactive and display profound autistic-like behavioural alterations including repetitive grooming as well as abnormalities in vocal and social behaviours. By comparing the data on ProSAP1/Shank2(-/-) mutants with ProSAP2/Shank3αβ(-/-) mice, we show that different abnormalities in synaptic glutamate receptor expression can cause alterations in social interactions and communication. Accordingly, we propose that appropriate therapies for autism spectrum disorders are to be carefully matched to the underlying synaptopathic phenotype.

  11. Impaired motor coordination in mice lacking the EDA exon of the fibronectin gene.

    PubMed

    Chauhan, Anil Kumar; Moretti, Federico Andrea; Iaconcig, Alessandra; Baralle, Francisco Ernesto; Muro, Andrés Fernando

    2005-06-03

    The extracellular matrix (ECM) plays an important role in the central nervous system (CNS) by modulating the migration of cells, axons and dendrites of neurons. Fibronectin (FN) is a major component of the ECM in the CNS and plays essential roles in development, cell adhesion and cell migration. Specific FN-isoforms, generated by alternative splicing at three conserved regions, the extra domain B (EDB), extra domain A (EDA) and type III homologies connecting segment (IIICS), have been shown to modulate these processes in vitro and in vivo. The inclusion of the EDA exon in the brain is highly regulated during development and aging, suggesting an important role of this exon in brain function. However, the direct role of FN-isoforms in brain function and behaviour is still obscure. Therefore, to directly assess the role of the FN-EDA exon in vivo, we have generated two mouse strains devoid of EDA exon regulated splicing in the FN gene that constitutively include (EDA(+/+)) or exclude (EDA(-/-)) the EDA exon in all tissues. Here, we show the behavioural consequences of the absence of regulated splicing of the EDA exon in the FN gene. Deletion of the EDA domain in the FN protein results in reduced motor-coordination abilities and vertical exploratory capacity, whereas mice that constitutively include the EDA domain displayed a decrease in locomotory activity in the open field (OF) test. These results strongly suggest that regulated splicing of the EDA exon is necessary for a normal function of the brain.

  12. Milk Lacking α-Casein Leads to Permanent Reduction in Body Size in Mice

    PubMed Central

    Kolb, Andreas F.; Huber, Reinhard C.; Lillico, Simon G.; Carlisle, Ailsa; Robinson, Claire J.; Neil, Claire; Petrie, Linda; Sorensen, Dorte B.; Olsson, I. Anna S.; Whitelaw, C. Bruce A.

    2011-01-01

    The major physiological function of milk is the transport of amino acids, carbohydrates, lipids and minerals to mammalian offspring. Caseins, the major milk proteins, are secreted in the form of a micelle consisting of protein and calcium-phosphate. We have analysed the role of the milk protein α-casein by inactivating the corresponding gene in mice. Absence of α-casein protein significantly curtails secretion of other milk proteins and calcium-phosphate, suggesting a role for α-casein in the establishment of casein micelles. In contrast, secretion of albumin, which is not synthesized in the mammary epithelium, into milk is not reduced. The absence of α-casein also significantly inhibits transcription of the other casein genes. α-Casein deficiency severely delays pup growth during lactation and results in a life-long body size reduction compared to control animals, but has only transient effects on physical and behavioural development of the pups. The data support a critical role for α-casein in casein micelle assembly. The results also confirm lactation as a critical window of metabolic programming and suggest milk protein concentration as a decisive factor in determining adult body weight. PMID:21789179

  13. Knowledge of the biological actions of extra virgin olive oil gained from mice lacking apolipoprotein E.

    PubMed

    Guillén, Natalia; Acín, Sergio; Navarro, María A; Surra, Joaquín Carlos; Arnal, Carmen; Lou-Bonafonte, José Manuel; Muniesa, Pedro; Martínez-Gracia, María Victoria; Osada, Jesús

    2009-03-01

    The low incidence of cardiovascular disease in countries bordering the Mediterranean basin, where olive oil is the main source of dietary fat, has stimulated interest in the chemical composition of olive oil and in the production of other oils enriched with its minor components. This review summarizes what has been learned about the effects of different olive oil preparations on the development of atherosclerosis and about the prognostic value of associated plasma variables in the disease from experiments on genetically modified mice that spontaneously develop atherosclerosis. The limitations of this animal model associated with its morphological and physiological differences with humans are minimized by the similarity of the two genomes and by the potential for increased understanding attainable, given that the dietary interventions reported here would have taken 400 years to achieve in humans. As observed in traditional Mediterranean populations, it has been confirmed that extra virgin olive oil is beneficial when consumed judiciously and in a diet that is low in cholesterol due to the relative scarcity of animal products. Furthermore, the use of genomic techniques has led to the identification of new markers of response to olive oil. In conclusion, multidisciplinary research into extra virgin olive oil is expanding our knowledge of the substance's biological properties.

  14. Tanapoxvirus lacking a neuregulin-like gene regresses human melanoma tumors in nude mice.

    PubMed

    Zhang, Tiantian; Suryawanshi, Yogesh R; Kordish, Dennis H; Woyczesczyk, Helene M; Jeng, David; Essani, Karim

    2017-02-01

    Neuregulin (NRG), an epidermal growth factor is known to promote the growth of various cell types, including human melanoma cells through ErbB family of tyrosine kinases receptors. Tanapoxvirus (TPV)-encoded protein TPV-15L, a functional mimic of NRG, also acts through ErbB receptors. Here, we show that the TPV-15L protein promotes melanoma proliferation. TPV recombinant generated by deleting the 15L gene (TPVΔ15L) showed replication ability similar to that of wild-type TPV (wtTPV) in owl monkey kidney cells, human lung fibroblast (WI-38) cells, and human melanoma (SK-MEL-3) cells. However, a TPV recombinant with both 15L and the thymidine kinase (TK) gene 66R ablated (TPVΔ15LΔ66R) replicated less efficiently compared to TPVΔ15L and the parental virus. TPVΔ15L exhibited more robust tumor regression in the melanoma-bearing nude mice compared to other TPV recombinants. Our results indicate that deletion of TPV-15L gene product which facilitates the growth of human melanoma cells can be an effective strategy to enhance the oncolytic potential of TPV for the treatment of melanoma.

  15. Xenobiotic Metabolism in Mice Lacking the UDP-Glucuronosyltransferase 2 Family.

    PubMed

    Fay, Matthew J; Nguyen, My Trang; Snouwaert, John N; Dye, Rebecca; Grant, Delores J; Bodnar, Wanda M; Koller, Beverly H

    2015-12-01

    UDP-Glucuronosyltransferases (UGTs) conjugate a glucuronyl group from glucuronic acid to a wide range of lipophilic substrates to form a hydrophilic glucuronide conjugate. The glucuronide generally has decreased bioactivity and increased water solubility to facilitate excretion. Glucuronidation represents an important detoxification pathway for both endogenous waste products and xenobiotics, including drugs and harmful industrial chemicals. Two clinically significant families of UGT enzymes are present in mammals: UGT1s and UGT2s. Although the two families are distinct in gene structure, studies using recombinant enzymes have shown considerable overlap in their ability to glucuronidate many substrates, often obscuring the relative importance of the two families in the clearance of particular substrates in vivo. To address this limitation, we have generated a mouse line, termed ΔUgt2, in which the entire Ugt2 gene family, extending over 609 kilobase pairs, is excised. This mouse line provides a means to determine the contributions of the two UGT families in vivo. We demonstrate the utility of these animals by defining for the first time the in vivo contributions of the UGT1 and UGT2 families to glucuronidation of the environmental estrogenic agent bisphenol A (BPA). The highest activity toward this chemical is reported for human and rodent UGT2 enzymes. Surprisingly, our studies using the ΔUgt2 mice demonstrate that, while both UGT1 and UGT2 isoforms can conjugate BPA, clearance is largely dependent on UGT1s.

  16. Lack of involvement of 6-hydroxymethylation in benzo[a]pyrene skin tumor initiation in mice.

    PubMed

    Slaga, T J; Bracken, W M; Viaje, A; Berry, D L; Fischer, S M; Miller, D R

    1978-08-01

    The skin tumor-initiating activities of benzo[a]pyrene (BP), 6-hydroxymethylbenzo[a]pyrene (6-OH-CH2-BP), and 6-methylbenzo[a]pyrene (6-CH3-BP), as well as the effects of 7,8-benzoflavone (7,8-BF), quercetin, and 1-benzylimidazole on their activity, were determined in outbred female CD-1 mice by use of a two stage system of tumorigenesis. The skin tumor-initiating activity of 6-OH-CH2-BP and 6-CH3-BP was 12.5 and 20%, respectively, of the activity of BP, 7,8-BF had little effect on the skin tumor-initiating activity of 6-OH-CH2-BP and 6-CH3-BP. However, a dose-dependent inhibition of BP tumorigenesis by 7,8-BF was noted. Quercetin and 1-benzylimidazole also inhibited BP skin tumor-initiating activity. These findings indicated that direct hydroxymethylation of BP is not an important pathway in the activation of BP in mouse skin tumor initiation.

  17. Dioxin induces Ahr-dependent robust DNA demethylation of the Cyp1a1 promoter via Tdg in the mouse liver

    NASA Astrophysics Data System (ADS)

    Amenya, Hesbon Z.; Tohyama, Chiharu; Ohsako, Seiichiroh

    2016-10-01

    The aryl hydrocarbon receptor (Ahr) is a highly conserved nuclear receptor that plays an important role in the manifestation of toxicity induced by polycyclic aromatic hydrocarbons. As a xenobiotic sensor, Ahr is involved in chemical biotransformation through activation of drug metabolizing enzymes. The activated Ahr cooperates with coactivator complexes to induce epigenetic modifications at target genes. Thus, it is conceivable that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a potent Ahr ligand, may elicit robust epigenetic changes in vivo at the Ahr target gene cytochrome P450 1a1 (Cyp1a1). A single dose of TCDD administered to adult mice induced Ahr-dependent CpG hypomethylation, changes in histone modifications, and thymine DNA glycosylase (Tdg) recruitment at the Cyp1a1 promoter in the liver within 24 hrs. These epigenetic changes persisted until 40 days post-TCDD treatment and there was Cyp1a1 mRNA hyperinduction upon repeat administration of TCDD at this time-point. Our demethylation assay using siRNA knockdown and an in vitro methylated plasmid showed that Ahr, Tdg, and the ten-eleven translocation methyldioxygenases Tet2 and Tet3 are required for the TCDD-induced DNA demethylation. These results provide novel evidence of Ahr-driven active DNA demethylation and epigenetic memory. The epigenetic alterations influence response to subsequent chemical exposure and imply an adaptive mechanism to xenobiotic stress.

  18. Dioxin induces Ahr-dependent robust DNA demethylation of the Cyp1a1 promoter via Tdg in the mouse liver

    PubMed Central

    Amenya, Hesbon Z.; Tohyama, Chiharu; Ohsako, Seiichiroh

    2016-01-01

    The aryl hydrocarbon receptor (Ahr) is a highly conserved nuclear receptor that plays an important role in the manifestation of toxicity induced by polycyclic aromatic hydrocarbons. As a xenobiotic sensor, Ahr is involved in chemical biotransformation through activation of drug metabolizing enzymes. The activated Ahr cooperates with coactivator complexes to induce epigenetic modifications at target genes. Thus, it is conceivable that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a potent Ahr ligand, may elicit robust epigenetic changes in vivo at the Ahr target gene cytochrome P450 1a1 (Cyp1a1). A single dose of TCDD administered to adult mice induced Ahr-dependent CpG hypomethylation, changes in histone modifications, and thymine DNA glycosylase (Tdg) recruitment at the Cyp1a1 promoter in the liver within 24 hrs. These epigenetic changes persisted until 40 days post-TCDD treatment and there was Cyp1a1 mRNA hyperinduction upon repeat administration of TCDD at this time-point. Our demethylation assay using siRNA knockdown and an in vitro methylated plasmid showed that Ahr, Tdg, and the ten-eleven translocation methyldioxygenases Tet2 and Tet3 are required for the TCDD-induced DNA demethylation. These results provide novel evidence of Ahr-driven active DNA demethylation and epigenetic memory. The epigenetic alterations influence response to subsequent chemical exposure and imply an adaptive mechanism to xenobiotic stress. PMID:27713569

  19. Enhanced corticosteroid signaling alters synaptic plasticity in the dentate gyrus in mice lacking the fragile X mental retardation protein.

    PubMed

    Ghilan, M; Hryciw, B N; Brocardo, P S; Bostrom, C A; Gil-Mohapel, J; Christie, B R

    2015-05-01

    The fragile X mental retardation protein (FMRP) is an important regulator of protein translation, and a lack of FMRP expression leads to a cognitive disorder known as fragile X syndrome (FXS). Clinical symptoms characterizing FXS include learning impairments and heightened anxiety in response to stressful situations. Here, we report that, in response to acute stress, mice lacking FMRP show a faster elevation of corticosterone and a more immediate impairment in N-methyl-d-aspartate receptor (NMDAR) dependent long-term potentiation (LTP) in the dentate gyrus (DG). These stress-induced LTP impairments were rescued by administering the glucocorticoid receptor (GR) antagonist RU38486. Administration of RU38486 also enhanced LTP in Fmr1(-/y) mice in the absence of acute stress to wild-type levels, and this enhancement was blocked by application of the NMDAR antagonist 2-amino-5-phosphonopentanoic acid. These results suggest that a loss of FMPR results in enhanced GR signaling that may adversely affect NMDAR dependent synaptic plasticity in the DG.

  20. Lack of Hypophagia in CB1 Null Mice is Associated to Decreased Hypothalamic POMC and CART Expression

    PubMed Central

    Parisi, Claudia; Seoane-Collazo, Patricia; Fernø, Johan; Mazza, Roberta; Bosch, Fátima; Seoane, Luisa M.; Nogueiras, Ruben; Diéguez, Carlos; Quarta, Carmelo; López, Miguel

    2015-01-01

    Background: Cumulative data indicate that the endocannabinoid system plays a major role in feeding behavior and energy balance. Genetic silencing of cannabinoid receptor type 1 (CB1) reduces body weight gain, independently of food intake. Methods: In this work, we investigated whether the hypothalamic neuropeptide expression pattern supports the absence of the anorexigenic response observed under constitutive CB1 ablation, by using neuronal CB1 conditional null mice (CamK-CB1-KO) and whole body CB1 null mice (CB1-KO). Results: Our data showed that both CB1 null models display a marked decrease in proopiomelanocortin (POMC) and cocaine-amphetamine-regulated transcript (CART) expression in the arcuate nucleus of the hypothalamus (ARC). Conclusions: This evidence suggests that a lack of hypophagia is associated with the suppression of ARC anorexigenic neuropeptides and that behavioral changes in food intake (or lack thereof) after constitutive CB1 ablation are likely mediated by impaired melanocortin and CART signaling in the hypothalamus. PMID:25655433

  1. The aryl hydrocarbon receptor inhibits prostate carcinogenesis in TRAMP mice.

    PubMed

    Fritz, Wayne A; Lin, Tien-Min; Cardiff, Robert D; Peterson, Richard E

    2007-02-01

    The aryl hydrocarbon receptor (AhR) is a transcription factor that mediates the inhibitory effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on prostate growth and also modulates normal prostate development. This is evidenced by AhR null mice (Ahr-/-) having smaller dorsolateral and anterior prostates, even though all prostate lobes remain histologically normal. To test the hypothesis that loss of the AhR increases the rate of prostate carcinogenesis, the incidence of macroscopic prostate tumors was determined in Ahr+/+, Ahr+/- and Ahr-/- C57BL/6J transgenic adenocarcinoma of the mouse prostate (TRAMP) mice at 35, 70, 105, 140, 175 and 210 days of age. From 140 days, prostate tumor incidence was greater in Ahr-/- (60%) and Ahr+/- (43%) mice than in Ahr+/+ mice (16%). Allele quantification did not indicate a loss of the wild-type Ahr allele in heterozygous TRAMP tumors, suggesting that tumor formation in these mice was not due to a loss of Ahr heterozygosity. Prostatic SV40 large T antigen mRNA expression and protein localization were comparable in TRAMP mice of each Ahr genotype. Prostates from all mice of each Ahr genotype were histologically indistinguishable, exhibiting diffuse epithelial hyperplasia by 105 days of age. mRNA expression and protein localization for molecular markers of neuroendocrine differentiation, including chromogranin A and neuropilin-1, were elevated in prostate tumors compared to tumor-free ventral prostates, regardless of Ahr genotype or age. Taken together, these results demonstrate that the Ahr inhibits prostate carcinogenesis in C57BL/6J TRAMP mice by interfering with neuroendocrine differentiation.

  2. Early lethality and neuronal proteinopathy in mice expressing cytoplasm-targeted FUS that lacks the RNA recognition motif

    PubMed Central

    ROBINSON, HANNAH K.; DEYKIN, ALEXEY V.; BRONOVITSKY, EVGENY V.; OVCHINNIKOV, RUSLAN K.; USTYUGOV, ALEXEY A.; SHELKOVNIKOVA, TATYANA A.; KUKHARSKY, MICHAIL S.; ERMOLKEVICH, TATYANA G.; GOLDMAN, IGOR L.; SADCHIKOVA, ELENA R.; KOVRAZHKINA, ELENA A.; BACHURIN, SERGEY O.; BUCHMAN, VLADIMIR L.; NINKINA, NATALIA N.

    2016-01-01

    Mutations to the RNA binding protein, fused in sarcoma (FUS) occur in ~5% of familial ALS and FUS-positive cytoplasmic inclusions are commonly observed in these patients. Altered RNA metabolism is increasingly implicated in ALS, yet it is not understood how the specificity with which FUS interacts with RNA in the cytoplasm can affect its aggregation in vivo. To further understand this, we expressed, in mice, a form of FUS (FUS ΔRRMcyt) that lacked the RNA recognition motif (RRM), thought to impart specificity to FUS-RNA interactions, and carried an ALS-associated point mutation, R522G, retaining the protein in the cytoplasm. Here we report the phenotype and results of histological assessment of the brain of transgenic mice expressing this isoform of FUS. Results demonstrated that neuronal expression of FUS ΔRRMcyt caused early lethality often preceded by severe tremor. Large FUS-positive cytoplasmic inclusions were found in many brain neurons; however, neither neuronal loss nor neuroinflammatory response was observed. In conclusion, the extensive FUS proteinopathy and severe phenotype of these mice suggests that affecting the interactions of FUS with RNA in vivo may augment its aggregation in the neuronal cytoplasm and the severity of disease processes. PMID:25991062

  3. Early lethality and neuronal proteinopathy in mice expressing cytoplasm-targeted FUS that lacks the RNA recognition motif.

    PubMed

    Robinson, Hannah K; Deykin, Alexey V; Bronovitsky, Evgeny V; Ovchinnikov, Ruslan K; Ustyugov, Alexey A; Shelkovnikova, Tatyana A; Kukharsky, Michail S; Ermolkevich, Tatyana G; Goldman, Igor L; Sadchikova, Elena R; Kovrazhkina, Elena A; Bachurin, Sergey O; Buchman, Vladimir L; Ninkina, Natalia N

    2015-01-01

    Mutations to the RNA binding protein, fused in sarcoma (FUS) occur in ∼5% of familial ALS and FUS-positive cytoplasmic inclusions are commonly observed in these patients. Altered RNA metabolism is increasingly implicated in ALS, yet it is not understood how the specificity with which FUS interacts with RNA in the cytoplasm can affect its aggregation in vivo. To further understand this, we expressed, in mice, a form of FUS (FUS ΔRRMcyt) that lacked the RNA recognition motif (RRM), thought to impart specificity to FUS-RNA interactions, and carried an ALS-associated point mutation, R522G, retaining the protein in the cytoplasm. Here we report the phenotype and results of histological assessment of the brain of transgenic mice expressing this isoform of FUS. Results demonstrated that neuronal expression of FUS ΔRRMcyt caused early lethality often preceded by severe tremor. Large FUS-positive cytoplasmic inclusions were found in many brain neurons; however, neither neuronal loss nor neuroinflammatory response was observed. In conclusion, the extensive FUS proteinopathy and severe phenotype of these mice suggests that affecting the interactions of FUS with RNA in vivo may augment its aggregation in the neuronal cytoplasm and the severity of disease processes.

  4. Overweight in Mice and Enhanced Adipogenesis In Vitro Are Associated With Lack of the Hedgehog Coreceptor Boc

    PubMed Central

    Lee, Hye-Jin; Jo, Shin-Bum; Romer, Anthony I.; Lim, Hyo-Jeong; Kim, Min-Jung; Koo, Seung-Hoi

    2015-01-01

    Obesity arises from a combination of genetic, environmental, and behavioral factors. However, the processes that regulate white adipose tissue (WAT) expansion at the level of the adipocyte are not well understood. The Hedgehog (HH) pathway plays a conserved role in adipogenesis, inhibiting fat formation in vivo and in vitro, but it has not been shown that mice with reduced HH pathway activity have enhanced adiposity. We report that mice lacking the HH coreceptor BOC displayed age-related overweight and excess WAT. They also displayed alterations in some metabolic parameters but normal food intake. Furthermore, they had an exacerbated response to a high-fat diet, including enhanced weight gain and adipocyte hypertrophy, livers with greater fat accumulation, and elevated expression of genes related to adipogenesis, lipid metabolism, and adipokine production. Cultured Boc−/− mouse embryo fibroblasts showed enhanced adipogenesis relative to Boc+/+ cells, and they expressed reduced levels of HH pathway target genes. Therefore, a loss-of-function mutation in an HH pathway component is associated with WAT accumulation and overweight in mice. Variant alleles of such HH regulators may contribute to WAT accumulation in human individuals with additional genetic or lifestyle-based predisposition to obesity. PMID:25576054

  5. Mice lacking thyroid hormone receptor Beta show enhanced apoptosis and delayed liver commitment for proliferation after partial hepatectomy.

    PubMed

    López-Fontal, Raquel; Zeini, Miriam; Través, Paqui G; Gómez-Ferrería, Mariana; Aranda, Ana; Sáez, Guillermo T; Cerdá, Concha; Martín-Sanz, Paloma; Hortelano, Sonsoles; Boscá, Lisardo

    2010-01-14

    The role of thyroid hormones and their receptors (TR) during liver regeneration after partial hepatectomy (PH) was studied using genetic and pharmacologic approaches. Roles in liver regeneration have been suggested for T3, but there is no clear evidence distinguishing the contribution of increased amounts of T3 from the modulation by unoccupied TRs. Mice lacking TRalpha1/TRbeta or TRbeta alone fully regenerated liver mass after PH, but showed delayed commitment to the initial round of hepatocyte proliferation and transient but intense apoptosis at 48h post-PH, affecting approximately 30% of the remaining hepatocytes. Pharmacologically induced hypothyroidism yielded similar results. Loss of TR activity was associated with enhanced nitrosative stress in the liver remnant, due to an increase in the activity of the nitric oxide synthase (NOS) 2 and 3, caused by a transient decrease in the concentration of asymmetric dimethylarginine (ADMA), a potent NOS inhibitor. This decrease in the ADMA levels was due to the presence of a higher activity of dimethylarginineaminohydrolase-1 (DDAH-1) in the regenerating liver of animals lacking TRalpha1/TRbeta or TRbeta. DDAH-1 expression and activity was paralleled by the activity of FXR, a transcription factor involved in liver regeneration and up-regulated in the absence of TR. We report that TRs are not required for liver regeneration; however, hypothyroid mice and TRbeta- or TRalpha1/TRbeta-deficient mice exhibit a delay in the restoration of liver mass, suggesting a specific role for TRbeta in liver regeneration. Altered regenerative responses are related with a delay in the expression of cyclins D1 and E, and the occurrence of liver apoptosis in the absence of activated TRbeta that can be prevented by administration of NOS inhibitors. Taken together, these results indicate that TRbeta contributes significantly to the rapid initial round of hepatocyte proliferation following PH, and improves the survival of the regenerating

  6. Mice Lacking Thyroid Hormone Receptor β Show Enhanced Apoptosis and Delayed Liver Commitment for Proliferation after Partial Hepatectomy

    PubMed Central

    López-Fontal, Raquel; Zeini, Miriam; Través, Paqui G.; Gómez-Ferrería, Mariana; Aranda, Ana; Sáez, Guillermo T.; Cerdá, Concha; Martín-Sanz, Paloma; Hortelano, Sonsoles; Boscá, Lisardo

    2010-01-01

    Background The role of thyroid hormones and their receptors (TR) during liver regeneration after partial hepatectomy (PH) was studied using genetic and pharmacologic approaches. Roles in liver regeneration have been suggested for T3, but there is no clear evidence distinguishing the contribution of increased amounts of T3 from the modulation by unoccupied TRs. Methodology/Principal Findings Mice lacking TRα1/TRβ or TRβ alone fully regenerated liver mass after PH, but showed delayed commitment to the initial round of hepatocyte proliferation and transient but intense apoptosis at 48h post-PH, affecting ∼30% of the remaining hepatocytes. Pharmacologically induced hypothyroidism yielded similar results. Loss of TR activity was associated with enhanced nitrosative stress in the liver remnant, due to an increase in the activity of the nitric oxide synthase (NOS) 2 and 3, caused by a transient decrease in the concentration of asymmetric dimethylarginine (ADMA), a potent NOS inhibitor. This decrease in the ADMA levels was due to the presence of a higher activity of dimethylarginineaminohydrolase-1 (DDAH-1) in the regenerating liver of animals lacking TRα1/TRβ or TRβ. DDAH-1 expression and activity was paralleled by the activity of FXR, a transcription factor involved in liver regeneration and up-regulated in the absence of TR. Conclusions/Significance We report that TRs are not required for liver regeneration; however, hypothyroid mice and TRβ– or TRα1/TRβ–deficient mice exhibit a delay in the restoration of liver mass, suggesting a specific role for TRβ in liver regeneration. Altered regenerative responses are related with a delay in the expression of cyclins D1 and E, and the occurrence of liver apoptosis in the absence of activated TRβ that can be prevented by administration of NOS inhibitors. Taken together, these results indicate that TRβ contributes significantly to the rapid initial round of hepatocyte proliferation following PH, and improves the

  7. Absence of deficits in social behaviors and ultrasonic vocalizations in later generations of mice lacking neuroligin4.

    PubMed

    Ey, E; Yang, M; Katz, A M; Woldeyohannes, L; Silverman, J L; Leblond, C S; Faure, P; Torquet, N; Le Sourd, A-M; Bourgeron, T; Crawley, J N

    2012-11-01

    Mutations in NLGN4X have been identified in individuals with autism spectrum disorders and other neurodevelopmental disorders. A previous study reported that adult male mice lacking neuroligin4 (Nlgn4) displayed social approach deficits in the three-chambered test, altered aggressive behaviors and reduced ultrasonic vocalizations. To replicate and extend these findings, independent comprehensive analyses of autism-relevant behavioral phenotypes were conducted in later generations of the same line of Nlgn4 mutant mice at the National Institute of Mental Health in Bethesda, MD, USA and at the Institut Pasteur in Paris, France. Adult social approach was normal in all three genotypes of Nlgn4 mice tested at both sites. Reciprocal social interactions in juveniles were similarly normal across genotypes. No genotype differences were detected in ultrasonic vocalizations in pups separated from the nest or in adults during reciprocal social interactions. Anxiety-like behaviors, self-grooming, rotarod and open field exploration did not differ across genotypes, and measures of developmental milestones and general health were normal. Our findings indicate an absence of autism-relevant behavioral phenotypes in subsequent generations of Nlgn4 mice tested at two locations. Testing environment and methods differed from the original study in some aspects, although the presence of normal sociability was seen in all genotypes when methods taken from Jamain et al. (2008) were used. The divergent results obtained from this study indicate that phenotypes may not be replicable across breeding generations, and highlight the significant roles of environmental, generational and/or procedural factors on behavioral phenotypes. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

  8. Absence of deficits in social behaviors and ultrasonic vocalizations in later generations of mice lacking neuroligin4

    PubMed Central

    Katz, A. M.; Woldeyohannes, L.; Silverman, J. L.; Leblond, C. S.; Faure, P.; Torquet, N.; Le Sourd, A.-M.

    2016-01-01

    Mutations in NLGN4X have been identified in individuals with autism spectrum disorders and other neurodevelopmental disorders. A previous study reported that adult male mice lacking neuroligin4 (Nlgn4) displayed social approach deficits in the three-chambered test, altered aggressive behaviors and reduced ultrasonic vocalizations. To replicate and extend these findings, independent comprehensive analyses of autism-relevant behavioral phenotypes were conducted in later generations of the same line of Nlgn4 mutant mice at the National Institute of Mental Health in Bethesda, MD, USA and at the Institut Pasteur in Paris, France. Adult social approach was normal in all three genotypes of Nlgn4 mice tested at both sites. Reciprocal social interactions in juveniles were similarly normal across genotypes. No genotype differences were detected in ultrasonic vocalizations in pups separated from the nest or in adults during reciprocal social interactions. Anxiety-like behaviors, self-grooming, rotarod and open field exploration did not differ across genotypes, and measures of developmental milestones and general health were normal. Our findings indicate an absence of autism-relevant behavioral phenotypes in subsequent generations of Nlgn4 mice tested at two locations. Testing environment and methods differed from the original study in some aspects, although the presence of normal sociability was seen in all genotypes when methods taken from Jamain et al. (2008) were used. The divergent results obtained from this study indicate that phenotypes may not be replicable across breeding generations, and highlight the significant roles of environmental, generational and/or procedural factors on behavioral phenotypes. PMID:22989184

  9. Important role of mucosal serotonin in colonic propulsion and peristaltic reflexes: in vitro analyses in mice lacking tryptophan hydroxylase 1.

    PubMed

    Heredia, Dante J; Gershon, Michael D; Koh, Sang Don; Corrigan, Robert D; Okamoto, Takanubu; Smith, Terence K

    2013-12-01

    Although there is general agreement that mucosal 5-hydroxytryptamine (5-HT) can initiate peristaltic reflexes in the colon, recent studies have differed as to whether or not the role of mucosal 5-HT is critical. We therefore tested the hypothesis that the secretion of 5-HT from mucosal enterochromaffin (EC) cells is essential for the manifestation of murine colonic peristaltic reflexes. To do so, we analysed the mechanisms underlying faecal pellet propulsion in isolated colons of mice lacking tryptophan hydroxylase 1 (Tph1(-/-) mice), which is the rate-limiting enzyme in the biosynthesis of mucosal but not neuronal 5-HT. We used video analysis of faecal pellet propulsion, tension transducers to record colonic migrating motor complexes (CMMCs) and intracellular microelectrodes to record circular muscle activity occurring spontaneously or following intraluminal distension. When compared with control (Tph1(+/+)) mice, Tph1(-/-) animals exhibited: (1) an elongated colon; (2) larger faecal pellets; (3) orthograde propulsion followed by retropulsion (not observed in Tph1(+/+) colon); (4) slower in vitro propulsion of larger faecal pellets (28% of Tph1(+/+)); (5) CMMCs that infrequently propagated in an oral to anal direction because of impaired descending inhibition; (6) reduced CMMCs and inhibitory responses to intraluminal balloon distension; (7) an absence of reflex activity in response to mucosal stimulation. In addition, (8) thin pellets that propagated along the control colon failed to do so in Tph1(-/-) colon; and (9) the 5-HT3 receptor antagonist ondansetron, which reduced CMMCs and blocked their propagation in Tph1(+/+) mice, failed to alter CMMCs in Tph1(-/-) animals. Our observations suggest that mucosal 5-HT is essential for reflexes driven by mucosal stimulation and is also important for normal propagation of CMMCs and propulsion of pellets in the isolated colon.

  10. Age-dependent gait abnormalities in mice lacking the Rnf170 gene linked to human autosomal-dominant sensory ataxia.

    PubMed

    Kim, Youngsoo; Kim, Seong Hun; Kim, Kook Hwan; Chae, Sujin; Kim, Chanki; Kim, Jeongjin; Shin, Hee-Sup; Lee, Myung-Shik; Kim, Daesoo

    2015-12-20

    Really interesting new gene (RING) finger protein 170 (RNF170) is an E3 ubiquitin ligase known to mediate ubiquitination-dependent degradation of type-I inositol 1,4,5-trisphosphate receptors (ITPR1). It has recently been demonstrated that a point mutation of RNF170 gene is linked with autosomal-dominant sensory ataxia (ADSA), which is characterized by an age-dependent increase of walking abnormalities, a rare genetic disorder reported in only two families. Although this mutant allele is known to be dominant, the functional identity thereof has not been clearly established. Here, we generated mice lacking Rnf170 (Rnf170(-/-)) to evaluate the effect of its loss of function in vivo. Remarkably, Rnf170(-/-) mice began to develop gait abnormalities in old age (12 months) in the form of asynchronous stepping between diagonal limb pairs with a fixed step sequence during locomotion, while age-matched wild-type mice showed stable gait patterns using several step sequence repertoires. As reported in ADSA patients, they also showed a reduced sensitivity for proprioception and thermal nociception. Protein blot analysis revealed that the amount of Itpr1 protein was significantly elevated in the cerebellum and spinal cord but intact in the cerebral cortex in Rnf170(-/-) mice. These results suggest that the loss of Rnf170 gene function mediates ADSA-associated phenotypes and this gives insights on the cure of patients with ADSA and other age-dependent walking abnormalities. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Human and rodent aryl hydrocarbon receptor (AHR): from mediator of dioxin toxicity to physiologic AHR functions and therapeutic options.

    PubMed

    Bock, Karl Walter

    2017-04-01

    Metabolism of aryl hydrocarbons and toxicity of dioxins led to the discovery of the aryl hydrocarbon receptor (AHR). Tremendous advances have been made on multiplicity of AHR signaling and identification of endogenous ligands including the tryptophan metabolites FICZ and kynurenine. However, human AHR functions are still poorly understood due to marked species differences as well as cell-type- and cell context-dependent AHR functions. Observations in dioxin-poisoned individuals may provide hints to physiologic AHR functions in humans. Based on these observations three human AHR functions are discussed: (1) Chemical defence and homeostasis of endobiotics. The AHR variant Val381 in modern humans leads to reduced AHR affinity to aryl hydrocarbons in comparison with Neanderthals and primates expressing the Ala381 variant while affinity to indoles remains unimpaired. (2) Homeostasis of stem/progenitor cells. Dioxins dysregulate homeostasis in sebocyte stem cells. (3) Modulation of immunity. In addition to microbial defence, AHR may be involved in a 'disease tolerance defence pathway'. Further characterization of physiologic AHR functions may lead to therapeutic options.

  12. Immunological Relevance of the Coevolution of IDO1 and AHR

    PubMed Central

    Jaronen, Merja; Quintana, Francisco J.

    2014-01-01

    The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor initially identified because of its role in controlling the cellular response to environmental molecules. More recently, AHR has been shown to play a crucial role in controlling innate and adaptive immune responses through several mechanisms, one of which is the regulation of tryptophan metabolism. Indoleamine-2,3-dioxygenase (IDO) and tryptophan-2,3-dioxygenase (TDO) are considered rate-limiting enzymes in the tryptophan catabolism and play important roles in the regulation of the immunity. Moreover, AHR and IDO/TDO are closely interconnected: AHR regulates IDO and TDO expression, and kynurenine produced by IDO/TDO is an AHR agonist. In this review, we propose to examine the relationship between AHR and IDO/TDO and its relevance for the regulation of the immune response in health and disease. PMID:25368620

  13. Lack of exercise leads to significant and reversible loss of scale invariance in both aged and young mice

    PubMed Central

    Gu, Changgui; Coomans, Claudia P.; Hu, Kun; Scheer, Frank A. J. L.; Stanley, H. Eugene; Meijer, Johanna H.

    2015-01-01

    In healthy humans and other animals, behavioral activity exhibits scale invariance over multiple timescales from minutes to 24 h, whereas in aging or diseased conditions, scale invariance is usually reduced significantly. Accordingly, scale invariance can be a potential marker for health. Given compelling indications that exercise is beneficial for mental and physical health, we tested to what extent a lack of exercise affects scale invariance in young and aged animals. We studied six or more mice in each of four age groups (0.5, 1, 1.5, and 2 y) and observed an age-related deterioration of scale invariance in activity fluctuations. We found that limiting the amount of exercise, by removing the running wheels, leads to loss of scale-invariant properties in all age groups. Remarkably, in both young and old animals a lack of exercise reduced the scale invariance in activity fluctuations to the same level. We next showed that scale invariance can be restored by returning the running wheels. Exercise during the active period also improved scale invariance during the resting period, suggesting that activity during the active phase may also be beneficial for the resting phase. Finally, our data showed that exercise had a stronger influence on scale invariance than the effect of age. The data suggest that exercise is beneficial as revealed by scale-invariant parameters and that, even in young animals, a lack of exercise leads to strong deterioration in these parameters. PMID:25675516

  14. The Nuclear Receptor AhR Controls Bone Homeostasis by Regulating Osteoclast Differentiation via the RANK/c-Fos Signaling Axis

    PubMed Central

    Izawa, Takashi; Arakaki, Rieko; Mori, Hiroki; Tsunematsu, Takaaki; Kudo, Yasusei; Tanaka, Eiji

    2016-01-01

    The aryl hydrocarbon receptor (AhR) pathway plays a key role in receptor activator of NF-κB ligand (RANKL)–mediated osteoclastogenesis. However, the mechanism underlying the regulation of AhR expression in osteoclasts and the signaling pathway through which AhR controls osteoclastogenesis remain unclear. We found that the expression of AhR in bone marrow–derived osteoclasts was upregulated by RANKL at an earlier stage than was the expression of signature osteoclast genes such as those encoding cathepsin K and NFAT, cytoplasmic, calcineurin-dependent 1. In response to RANKL, bone marrow macrophages isolated from AhR−/− mice exhibited impaired phosphorylation of Akt and MAPK as well as NF-κB, whereas their response to M-CSF remained unchanged. Osteoclast differentiation mediated by the AhR signaling pathway was also regulated in an RANKL/c-Fos–dependent manner. Furthermore, ligand activation of AhR by the smoke toxin benzo[a]pyrene accelerated osteoclast differentiation in a receptor-dependent manner, and AhR-dependent regulation of mitochondrial biogenesis in osteoclasts was observed. Moreover, AhR−/− mice exhibited impaired bone healing with delayed endochondral ossification. Taken together, the present results suggest that the RANKL/AhR/c-Fos signaling axis plays a critical role in osteoclastogenesis, thereby identifying the potential of AhR in treating pathological, inflammatory, or metabolic disorders of the bone. PMID:27849171

  15. Inhibition of Stat3 signaling ameliorates atrophy of the soleus muscles in mice lacking the vitamin D receptor.

    PubMed

    Gopinath, Suchitra D

    2017-01-25

    Although skeletal muscle wasting has long been observed as a clinical outcome of impaired vitamin D signaling, precise molecular mechanisms that mediate the loss of muscle mass in the absence of vitamin D signaling are less clear. To determine the molecular consequences of vitamin D signaling, we analyzed the role of signal transducer and activator of transcription 3 (Stat3) signaling, a known contributor to various muscle wasting pathologies, in skeletal muscles. We isolated soleus (slow) and tibialis anterior (fast) muscles from mice lacking the vitamin D receptor (VDR(-/-)) and used western blot analysis, quantitative RTPCR, and pharmacological intervention to analyze muscle atrophy in VDR(-/-) mice. We found that slow and fast subsets of muscles of the VDR(-/-) mice displayed elevated levels of phosphorylated Stat3 accompanied by an increase in Myostatin expression and signaling. Consequently, we observed reduced activity of mammalian target of rapamycin (mTOR) signaling components, ribosomal S6 kinase (p70S6K) and ribosomal S6 protein (rpS6), that regulate protein synthesis and cell size, respectively. Concomitantly, we observed an increase in atrophy regulators and a block in autophagic gene expression. An examination of the upstream regulation of Stat3 levels in VDR(-/-) muscles revealed an increase in IL-6 protein expression in the soleus, but not in the tibialis anterior muscles. To investigate the involvement of satellite cells (SCs) in atrophy in VDR(-/-) mice, we found that there was no significant deficit in SC numbers in VDR(-/-) muscles compared to the wild type. Unlike its expression within VDR(-/-) fibers, Myostatin levels in VDR(-/-) SCs from bulk muscles were similar to those of wild type. However, VDR(-/-) SCs induced to differentiate in culture displayed increased p-Stat3 signaling and Myostatin expression. Finally, VDR(-/-) mice injected with a Stat3 inhibitor displayed reduced Myostatin expression and function and restored active p70S6K and

  16. Deafness and renal tubular acidosis in mice lacking the K-Cl co-transporter Kcc4.

    PubMed

    Boettger, Thomas; Hübner, Christian A; Maier, Hannes; Rust, Marco B; Beck, Franz X; Jentsch, Thomas J

    2002-04-25

    Hearing depends on a high K(+) concentration bathing the apical membranes of sensory hair cells. K(+) that has entered hair cells through apical mechanosensitive channels is transported to the stria vascularis for re-secretion into the scala media(). K(+) probably exits outer hair cells by KCNQ4 K(+) channels(), and is then transported by means of a gap junction system connecting supporting Deiters' cells and fibrocytes() back to the stria vascularis. We show here that mice lacking the K(+)/Cl(-) (K-Cl) co-transporter Kcc4 (coded for by Slc12a7) are deaf because their hair cells degenerate rapidly after the beginning of hearing. In the mature organ of Corti, Kcc4 is restricted to supporting cells of outer and inner hair cells. Our data suggest that Kcc4 is important for K(+) recycling() by siphoning K(+) ions after their exit from outer hair cells into supporting Deiters' cells, where K(+) enters the gap junction pathway. Similar to some human genetic syndromes(), deafness in Kcc4-deficient mice is associated with renal tubular acidosis. It probably results from an impairment of Cl(-) recycling across the basolateral membrane of acid-secreting alpha-intercalated cells of the distal nephron.

  17. Yolk sac angiogenic defect and intra-embryonic apoptosis in mice lacking the Ets-related factor TEL.

    PubMed Central

    Wang, L C; Kuo, F; Fujiwara, Y; Gilliland, D G; Golub, T R; Orkin, S H

    1997-01-01

    The TEL gene, which is frequently rearranged in human leukemias of both myeloid and lymphoid origin, encodes a member of the Ets family of transcription factors. The TEL gene is widely expressed throughout embryonic development and in the adult. To determine the requirement for the TEL gene product in development we generated TEL knockout mice (TEL-/-) by gene targeting in embryonic stem cells. TEL-/- mice are embryonic lethal and die between E10.5-11.5 with defective yolk sac angiogenesis and intra-embryonic apoptosis of mesenchymal and neural cells. Two-thirds of TEL-deficient yolk sacs at E9.5 lack vitelline vessels, yet possess capillaries, indicative of normal vasculogenesis. Vitelline vessels regress by E10.5 in the remaining TEL-/- yolk sacs. Hematopoiesis at the yolk sac stage, however, appears unaffected in TEL-/- embryos. Our findings demonstrate that TEL is required for maintenance of the developing vascular network in the yolk sac and for survival of selected cell types within the embryo proper. PMID:9250681

  18. Lack of Genomic Instability in Bone Marrow Cells of SCID Mice Exposed Whole-Body to Low-Dose Radiation

    PubMed Central

    Rithidech, Kanokporn Noy; Udomtanakunchai, Chatchanok; Honikel, Louise; Whorton, Elbert

    2013-01-01

    It is clear that high-dose radiation is harmful. However, despite extensive research, assessment of potential health-risks associated with exposure to low-dose radiation (at doses below or equal to 0.1 Gy) is still challenging. Recently, we reported that 0.05 Gy of 137Cs gamma rays (the existing limit for radiation-exposure in the workplace) was incapable of inducing significant in vivo genomic instability (measured by the presence of late-occurring chromosomal damage at 6 months post-irradiation) in bone marrow (BM) cells of two mouse strains, one with constitutively high and one with intermediate levels of the repair enzyme DNA-dependent protein-kinase catalytic-subunit (DNA-PKcs). In this study, we present evidence for a lack of genomic instability in BM cells of the severely combined-immunodeficiency (SCID/J) mouse (which has an extremely low-level of DNA-PKcs activity) exposed whole-body to low-dose radiation (0.05 Gy). Together with our previous report, the data indicate that low-dose radiation (0.05 Gy) is incapable of inducing genomic instability in vivo (regardless of the levels of DNA-PKcs activity of the exposed mice), yet higher doses of radiation (0.1 and 1 Gy) do induce genomic instability in mice with intermediate and extremely low-levels of DNA-PKcs activity (indicating an important role of DNA-PKcs in DNA repair). PMID:23549227

  19. Beige differentiation of adipose depots in mice lacking prolactin receptor protects against high-fat-diet-induced obesity.

    PubMed

    Auffret, Julien; Viengchareun, Say; Carré, Nadège; Denis, Raphaël G P; Magnan, Christophe; Marie, Pierre-Yves; Muscat, Adeline; Fève, Bruno; Lombès, Marc; Binart, Nadine

    2012-09-01

    Stimulating conversion of white fat to metabolically active adipocytes (beige fat) constitutes a promising strategy against weight gain and its deleterious associated-disorders. We provide direct evidence that prolactin (PRL), best known for its actions on the mammary gland, plays a pivotal role in energy balance through the control of adipocyte differentiation and fate. Here we show that lack of prolactin receptor (PRLR) causes resistance to high-fat-diet-induced obesity due to enhanced energy expenditure and increased metabolic rate. Mutant mice displayed reduced fat mass associated with appearance of massive brown-like adipocyte foci in perirenal and subcutaneous but not in gonadal fat depots under a high-fat diet. Positron emission tomography imaging further demonstrated the occurrence of these thermogenic brown fat depots in adult mice, providing additional support for recruitable brown-like adipocytes (beigeing) in white fat depots. Consistent with the activation of brown adipose tissue, PRLR inactivation increases expression of master genes controlling brown adipocyte fate (PRDM16) and mitochondrial function (PGC1α, UCP1). Altered pRb/Foxc2 expression suggests that this PRL-regulated pathway may contribute to beige cell commitment. Together, these results provide direct genetic evidence that PRLR affects energy balance and metabolic adaptation in rodents via effects on brown adipose tissue differentiation and function.

  20. Lack of TCRalphabeta+ CD8+ and TCRgammadelta+ lymphocytes ameliorates LPS induced orchitis in mice--preliminary histological observations.

    PubMed

    Sliwa, Leopold; Macura, Barbara; Majewska-Szczepanik, Monika; Szczepanik, Marian

    2014-01-01

    The inflammation of the reproductive system can affect reproduction causing partial or complete infertility. It is well known that lipopolysaccharide (LPS) triggers an inflammatory response in the whole organism, including immunologically privileged organs, e.g. the testicles. Adult male TCRalpha-/-, TCRdelta-/-, CD1d-/- and beta2m-/- on B10.PL (H-2(u)) and B10.PL control mice were intraperitonealy (i.p.) injected with lipopolysaccharide (LPS). The animals were killed 24h and 10 days post LPS treatment and their gonads were prepared for microscopic examination. Histological changes in the testes after LPS injection were found only in control B10PL and CD1d-/- mice. The experiments revealed disturbances in Leydig's glands structure, blood vessel dilatation in the interstitial tissue as well as degeneration of seminal tubule epithelium, disruption ofspermatogenesis and subsequent decrease of sperm cell number in the tubule lumen. These changes were noticed mainly 10 days after LPS treatment. Lack of either TCRalphabeta+ CD8+ or TCRgammadelta+ lymphocytes diminishes the response of testicular macrophages to LPS whereas the absence of CD1d-dependent NKT cells does not affect macrophage reactivity.

  1. Mice lacking the transcription factor Mist1 exhibit an altered stress response and increased sensitivity to caerulein-induced pancreatitis.

    PubMed

    Kowalik, Agnes S; Johnson, Charis L; Chadi, Sami A; Weston, Jacqueline Y; Fazio, Elena N; Pin, Christopher L

    2007-04-01

    Several animal models have been developed to investigate the pathobiology of pancreatitis, but few studies have examined the effects that altered pancreatic gene expression have in these models. In this study, the sensitivity to secretagogue-induced pancreatitis was examined in a mouse line that has an altered acinar cell environment due to the targeted deletion of Mist1. Mist1 is an exocrine specific transcription factor important for the complete differentiation and function of pancreatic acinar cells. Mice lacking the Mist1 gene [Mist1 knockout (KO) mice] exhibit cellular disorganization and functional defects in the exocrine pancreas but no gross morphological defects. Following the induction of pancreatitis with caerulein, a CCK analog, we observed elevated serum amylase levels, necrosis, and tissue damage in Mist1 KO mice, indicating increased pancreatic damage. There was also a delay in the regeneration of acinar tissue in Mist1 KO animals. Molecular profiling revealed an altered activation of stress response genes in Mist1 KO pancreatic tissue compared with wild-type (WT) tissue following the induction of pancreatitis. In particular, Western blot analysis for activating transcription factor 3 and phosphorylated eukaryotic initiation factor 2alpha (eIF2alpha), mediators of endoplasmic reticulum (ER) stress, indicated limited activation of this pathway in Mist1 KO animals compared with WT controls. Conversely, Mist1 KO pancreatic tissue exhibits increased expression of growth arrest and DNA damage inducible 34 protein, an inhibitor of eIF2alpha phosphorylation, before and after the induction of pancreatitis. These finding suggest that activation of the ER stress pathway is a protective event in the progression of pancreatitis and highlight the Mist1 KO mouse line as an important new model for studying the molecular events that contribute to the sensitivity to pancreatic injury.

  2. T Cells That React to the Immunodominant Leishmania major LACK Antigen Prevent Early Dissemination of the Parasite in Susceptible BALB/c Mice

    PubMed Central

    Schilling, Sabrina; Glaichenhaus, Nicolas

    2001-01-01

    Susceptibility of BALB/c mice to Leishmania major depends on the early production of IL-4 by CD4+ T cells which react to the parasite LACK antigen. Here, we show that LACK-specific cells are rapidly recruited to the site of infection and favor the early dissemination of L. major to the internal organs. PMID:11160025

  3. The genome-wide transcriptional response to neonatal hyperoxia identifies Ahr as a key regulator

    PubMed Central

    Bhattacharya, Soumyaroop; Zhou, Zhongyang; Yee, Min; Chu, Chin-Yi; Lopez, Ashley M.; Lunger, Valerie A.; Solleti, Siva Kumar; Resseguie, Emily; Buczynski, Bradley; O'Reilly, Michael A.

    2014-01-01

    Premature infants requiring supplemental oxygen are at increased risk for developing bronchopulmonary dysplasia (BPD). Rodent models involving neonatal exposure to excessive oxygen concentrations (hyperoxia) have helped to identify mechanisms of BPD-associated pathology. Genome-wide assessments of the effects of hyperoxia in neonatal mouse lungs could identify novel BPD-related genes and pathways. Newborn C57BL/6 mice were exposed to 100% oxygen for 10 days, and whole lung tissue RNA was used for high-throughput, sequencing-based transcriptomic analysis (RNA-Seq). Significance Analysis of Microarrays and Ingenuity Pathway Analysis were used to identify genes and pathways affected. Expression patterns for selected genes were validated by qPCR. Mechanistic relationships between genes were further tested in cultured mouse lung epithelial cells. We identified 300 genes significantly and substantially affected following acute neonatal hyperoxia. Canonical pathways dysregulated in hyperoxia lungs included nuclear fctor (erythryoid-derived-2)-like 2-mediated oxidative stress signaling, p53 signaling, eNOS signaling, and aryl hydrocarbon receptor (Ahr) pathways. Cluster analysis identified Ccnd1, Cdkn1a, and Ahr as critical regulatory nodes in the response to hyperoxia, with Ahr serving as the major effector node. A mechanistic role for Ahr was assessed in lung epithelial cells, and we confirmed its ability to regulate the expression of multiple hyperoxia markers, including Cdkn1a, Pdgfrb, and A2m. We conclude that a global assessment of gene regulation in the acute neonatal hyperoxia model of BPD-like pathology has identified Ahr as one driver of gene dysregulation. PMID:25150061

  4. Human opiorphin: the lack of physiological dependence, tolerance to antinociceptive effects and abuse liability in laboratory mice.

    PubMed

    Popik, Piotr; Kamysz, Elzbieta; Kreczko, Joanna; Wróbel, Małgorzata

    2010-11-12

    Like other endogenous enkephalinase inhibitors, human opiorphin peptide (QRFSR) attenuates catabolism of enkephalins and appears to be a promising therapeutic, displaying antinociceptive action in several pain models. However, its opioid-like side-effect profile is insufficiently characterized. In the present set of experiments, acute intraperitoneal administration of opiorphin produced an antinociceptive effect in the tail-flick test in mice (0.3mg/kg) and this action was inhibited by opioid receptor antagonist naloxone (3mg/kg). Repeated treatment with opiorphin changed the antinociceptive response neither to itself nor to morphine, suggesting the lack of tolerance and morphine cross-tolerance, respectively. Repeated treatment with opiorphin (3mg/kg) also failed to produce opioid dependence. Opiorphin (0.3 or 1mg/kg) produced no rewarding effects in the conditioned place preference test. However, at the dose of 3mg/kg, the peptide produced antidepressant-like effect in the forced swim test, and it did not affect locomotor activity. The present set of results confirms the beneficial effects of opiorphin in pain management, and suggests a lack of opioid-like side effects as well as the presence of antidepressant-like actions of this peptide.

  5. Functional and phenotypic effects of AhR activation in inflammatory dendritic cells

    SciTech Connect

    Bankoti, Jaishree; Rase, Ben; Simones, Tom; Shepherd, David M.

    2010-07-15

    Aryl hydrocarbon receptor (AhR) activation by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces immune suppression. Dendritic cells (DCs) are key antigen presenting cells governing T cell activation and differentiation. However, the consequences of AhR activation in DCs are not fully defined. We hypothesized that AhR activation alters DC differentiation and generates dysfunctional DCs. To test this hypothesis, inflammatory bone marrow-derived DCs (BMDCs) from C57Bl/6 mice were generated in the presence of vehicle or TCDD. TCDD decreased CD11c expression but increased MHC class II, CD86 and CD25 expression on the BMDCs. The effects of TCDD were strictly AhR-dependent but not exclusively DRE-mediated. Similar effects were observed with two natural AhR ligands, 6-formylindolo[3,2-b]carbazole (FICZ) and 2-(1H-Indol-3-ylcarbonyl)-4-thiazolecarboxylic acid (ITE). TCDD increased LPS- and CpG-induced IL-6 and TNF-{alpha} production by BMDCs but decreased their NO production. TCDD decreased CpG-induced IL-12p70 production by BMDCs but did not affect their secretion of IL-10. TCDD downregulated LPS- and CpG-induced NF-kB p65 levels and induced a trend towards upregulation of RelB levels in the BMDCs. AhR activation by TCDD modulated BMDC uptake of both soluble and particulate antigens. Induction of indoleamine-2,3-dioxygenase (IDO) and TGF-{beta}3 has been implicated in the generation of regulatory T cells following AhR activation. TCDD increased IDO1, IDO2 and TGF-{beta}3 mRNA levels in BMDCs as compared to vehicle. Despite the induction of regulatory mediators, TCDD-treated BMDCs failed to suppress antigen-specific T cell activation. Thus, AhR activation can directly alter the differentiation and innate functions of inflammatory DCs without affecting their ability to successfully interact with T cells.

  6. NcoA2-Dependent Inhibition of HIF-1α Activation Is Regulated via AhR.

    PubMed

    Tsai, Chi-Hao; Li, Ching-Hao; Liao, Po-Lin; Cheng, Yu-Wen; Lin, Cheng-Hui; Huang, Shih-Hsuan; Kang, Jaw-Jou

    2015-12-01

    High endogenous levels of aryl hydrocarbon receptor (AhR) contribute to hypoxia signaling pathway inhibition following exposure to the potent AhR ligand benzo[a]pyrene (B[a]P) and could alter cellular homeostasis and disease condition. Increasing evidence indicates that AhR might compete with AhR nuclear translocator (ARNT) for complex formation with hypoxia-inducible factor-1α (HIF-1α) for transactivation, which could alter several physiological variables. Nuclear receptor coactivator 2 (NcoA2) is a transcription coactivator that regulates transcription factor activation and inhibition of basic helix-loop-helix Per (Period)-ARNT-SIM (single-minded) (bHLH-PAS) family proteins, such as HIF-1α, ARNT, and AhR, through protein-protein interactions. In this study, we demonstrated that both hypoxia and hypoxia-mimic conditions decreased NcoA2 protein expression in HEK293T cells. Hypoxia response element (HRE) and xenobiotic-responsive element (XRE) transactivation also were downregulated with NcoA2 knockdown under hypoxic conditions. In addition, B[a]P significantly decreased NcoA2 protein expression be accompanied with AhR degradation. We next evaluated whether the absence of AhR could affect NcoA2 protein function under hypoxia-mimetic conditions. NcoA2 and HIF-1α nuclear localization decreased in both B[a]P-pretreated and AhR-knockdown HepG2 cells under hypoxia-mimic conditions. Interestingly, NcoA2 overexpression downregulated HRE transactivation by competing with HIF-1α and AhR to form protein complexes with ARNT. Both NcoA2 knockdown and overexpression inhibited endothelial cell tube formation in vitro. We also demonstrated using the in vivo plug assay that NcoA2-regulated vascularization decreased in mice. Taken together, these results revealed a biphasic role of NcoA2 between AhR and hypoxic conditions, thus providing a novel mechanism underlying the cross talk between AhR and hypoxia that affects disease development and progression.

  7. Conditioned place preference and locomotor activity in response to methylphenidate, amphetamine and cocaine in mice lacking dopamine D4 receptors

    SciTech Connect

    Thanos, P.K.; Thanos, P.K.; Bermeo, C.; Rubinstein, M.; Suchland, K.L.; Wang, G.-J.; Grandy, D.K.; Volkow, N.D.

    2010-05-01

    Methylphenidate (MP) and amphetamine (AMPH) are the most frequently prescribed medications for the treatment of attention-deficit/hyperactivity disorder (ADHD). Both drugs are believed to derive their therapeutic benefit by virtue of their dopamine (DA)-enhancing effects, yet an explanation for the observation that some patients with ADHD respond well to one medication but not to the other remains elusive. The dopaminergic effects of MP and AMPH are also thought to underlie their reinforcing properties and ultimately their abuse. Polymorphisms in the human gene that codes for the DA D4 receptor (D4R) have been repeatedly associated with ADHD and may correlate with the therapeutic as well as the reinforcing effects of responses to these psychostimulant medications. Conditioned place preference (CPP) for MP, AMPH and cocaine were evaluated in wild-type (WT) mice and their genetically engineered littermates, congenic on the C57Bl/6J background, that completely lack D4Rs (knockout or KO). In addition, the locomotor activity in these mice during the conditioning phase of CPP was tested in the CPP chambers. D4 receptor KO and WT mice showed CPP and increased locomotor activity in response to each of the three psychostimulants tested. D4R differentially modulates the CPP responses to MP, AMPH and cocaine. While the D4R genotype affected CPP responses to MP (high dose only) and AMPH (low dose only) it had no effects on cocaine. Inasmuch as CPP is considered an indicator of sensitivity to reinforcing responses to drugs these data suggest a significant but limited role of D4Rs in modulating conditioning responses to MP and AMPH. In the locomotor test, D4 receptor KO mice displayed attenuated increases in AMPH-induced locomotor activity whereas responses to cocaine and MP did not differ. These results suggest distinct mechanisms for D4 receptor modulation of the reinforcing (perhaps via attenuating dopaminergic signalling) and locomotor properties of these stimulant drugs

  8. Sympathetic activity induced by naloxone-precipitated morphine withdrawal is blocked in genetically engineered mice lacking functional CRF1 receptor

    SciTech Connect

    García-Carmona, Juan-Antonio; Martínez-Laorden, Elena; Milanés, María-Victoria; Laorden, María-Luisa

    2015-02-15

    There is large body evidence indicating that stress can lead to cardiovascular disease. However, the exact brain areas and the mechanisms involved remain to be revealed. Here, we performed a series of experiments to characterize the role of CRF1 receptor (CRF1R) in the stress response induced by naloxone-precipitated morphine withdrawal. The experiments were performed in the hypothalamic paraventricular nucleus (PVN) ventrolateral medulla (VLM), brain regions involved in the regulation of cardiovascular activity, and in the right ventricle by using genetically engineered mice lacking functional CRF1R levels (KO). Mice were treated with increasing doses of morphine and withdrawal was precipitated by naloxone administration. Noradrenaline (NA) turnover, c-Fos, expression, PKA and TH phosphorylated at serine 40, was evaluated by high-performance liquid chromatography (HPLC), immunohistochemistry and immunoblotting. Morphine withdrawal induced an enhancement of NA turnover in PVN in parallel with an increase in TH neurons expressing c-Fos in VLM in wild-type mice. In addition we have demonstrated an increase in NA turnover, TH phosphorylated at serine 40 and PKA levels in heart. The main finding of the present study was that NA turnover, TH positive neurons that express c-Fos, TH phosphorylated at serine 40 and PKA expression observed during morphine withdrawal were significantly inhibited in CRF1R KO mice. Our results demonstrate that CRF/CRF1R activation may contribute to the adaptive changes induced by naloxone-precipitated withdrawal in the heart and in the brain areas which modulate the cardiac sympathetic function and suggest that CRF/CRF1R pathways could be contributing to cardiovascular disease associated to opioid addiction. - Highlights: • Naloxone-precipitated morphine withdrawal increases sympathetic activity in the PVN and heart. • Co-localization of TH phosphorylated at serine 40/c-Fos in the VLM after morphine withdrawal • Naloxone

  9. Functionality of aryl hydrocarbon receptors (AhR1 and AhR2) of white sturgeon (Acipenser transmontanus) and implications for the risk assessment of dioxin-like compounds.

    PubMed

    Doering, Jon A; Farmahin, Reza; Wiseman, Steve; Kennedy, Sean W; Giesy, John P; Hecker, Markus

    2014-07-15

    Worldwide, populations of sturgeons are endangered, and it is hypothesized that anthropogenic chemicals, including dioxin-like compounds (DLCs), might be contributing to the observed declines in populations. DLCs elicit their toxic action through activation of the aryl hydrocarbon receptor (AhR), which is believed to regulate most, if not all, adverse effects associated with exposure to these chemicals. Currently, risk assessment of DLCs in fishes uses toxic equivalency factors (TEFs) developed for the World Health Organization (WHO) that are based on studies of embryo-lethality with salmonids. However, there is a lack of knowledge of the sensitivity of sturgeons to DLCs, and it is uncertain whether TEFs developed by the WHO are protective of these fishes. Sturgeons are evolutionarily distinct from salmonids, and the AhRs of sturgeons differ from those of salmonids. Therefore, this study investigated the sensitivity of white sturgeon (Acipenser transmontanus) to DLCs in vitro via the use of luciferase reporter gene assays using COS-7 cells transfected with AhR1 or AhR2 of white sturgeon. Specifically, activation and relative potencies (RePs) of 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD), 2,3,4,7,8-pentachloro-dibenzofuran, 2,3,7,8-tetrachloro-dibenzofuran, 3,3',4,4',5-pentachlorobiphenyl, 3,3',4,4'-tetrachlorobiphenyl, and 2,3,3',4,4'-pentachlorobiphenyl were determined for each AhR. It was demonstrated that white sturgeon expresses AhR1s and AhR2s that are both activated by DLCs with EC50 values for 2,3,7,8-TCDD that are lower than those of any other AhR of vertebrates tested to date. Both AhRs of white sturgeon had RePs for polychlorinated dibenzofurans more similar to TEFs for birds, while RePs for polychlorinated biphenyls were most similar to TEFs for fishes. Measured concentrations of select DLCs in tissues of white sturgeon from British Columbia, Canada, were used to calculate toxic equivalents (TEQs) by use of TEFs for fishes used by the WHO and TCDD

  10. TOXICITY OF AHR AGONISTS TO FISH EARLY LIFE STAGES

    EPA Science Inventory

    Fish early life stages are exceptionally sensitive to the lethal toxicity of chemicals that act as arylhydrocarbon receptor (AhR) agonists. Toxicity characterizations based on 2,3,7,8-tetrachlorodibenzo-p-dioxin, generally the most potent AhR agonist, support the toxicity equiva...

  11. Teratogenic impact of dioxin-activated AHR in laboratory animals

    EPA Science Inventory

    AHR and ARNT are expressed in mouse and human palatal shelves and in the urinary tract of the mouse fetus. AHR expression, translocation to the nucleus, binding to DRE, and activation are required for mediation of TCDD-induction of CP and HN. Although the human palate requires a ...

  12. TOXICITY OF AHR AGONISTS TO FISH EARLY LIFE STAGES

    EPA Science Inventory

    Fish early life stages are exceptionally sensitive to the lethal toxicity of chemicals that act as arylhydrocarbon receptor (AhR) agonists. Toxicity characterizations based on 2,3,7,8-tetrachlorodibenzo-p-dioxin, generally the most potent AhR agonist, support the toxicity equiva...

  13. Teratogenic impact of dioxin-activated AHR in laboratory animals

    EPA Science Inventory

    AHR and ARNT are expressed in mouse and human palatal shelves and in the urinary tract of the mouse fetus. AHR expression, translocation to the nucleus, binding to DRE, and activation are required for mediation of TCDD-induction of CP and HN. Although the human palate requires a ...

  14. Lack of Maternal Glutamate Cysteine Ligase Modifier Subunit (Gclm) Decreases Oocyte Glutathione Concentrations and Disrupts Preimplantation Development in Mice

    PubMed Central

    Nakamura, Brooke N.; Fielder, Thomas J.; Hoang, Yvonne D.; Lim, Jinhwan; McConnachie, Lisa A.; Kavanagh, Terrance J.

    2011-01-01

    Glutathione (GSH) is the most abundant intracellular thiol and an important regulator of cellular redox status. Mice that lack the modifier subunit of glutamate cysteine ligase (Gclm), the rate-limiting enzyme in GSH synthesis, have decreased GSH synthesis. Nicotinamide nucleotide transhydrogenase, an inner mitochondrial membrane protein, catalyzes the interconversion of reduced nicotinamide adenine dinucleotide and reduced nicotinamide adenine dinucleotide phosphate; reduced nicotinamide adenine dinucleotide phosphate is required for reduction of GSH disulfide. Previous work supports roles for GSH in preimplantation development. We hypothesized that Gclm−/− mice have increased preimplantation embryonic mortality and that this effect is enhanced by absence of a functioning Nnt gene. Gclm−/− females produced significantly fewer pups per litter than Gclm+/+ littermates. Numbers of oocytes ovulated in a natural estrous cycle or upon superovulation did not differ by genotype. Fewer uterine implantation sites were observed in the Gclm−/− females. Prepubertal Gclm−/− and Gclm+/+ females were superovulated, then mated overnight with a Gclm+/+ male. At 0.5 d postcoitum, Gclm−/− females had significantly lower percentages of zygotes with two pronuclei and higher percentages of zygotes with one pronucleus than Gclm+/+ or Gclm+/− females. At 3.5 d postcoitum, a significantly lower percentage of blastocyst stage embryos was recovered from uteri of Gclm−/− females than Gclm+/+ females. Embryonic development to the blastocyst stage, but not the two-cell stage, was significantly decreased after in vitro fertilization of oocytes from Gclm−/− females compared with Gclm+/+ females. The Nnt mutation did not enhance the effects of Gclm genotype on female fertility. These results demonstrate critical roles for maternal GSH in supporting normal preimplantation development. PMID:21558310

  15. D-amphetamine and antipsychotic drug effects on latent inhibition in mice lacking dopamine D2 receptors.

    PubMed

    Bay-Richter, C; O'Callaghan, M J; Mathur, N; O'Tuathaigh, C M P; Heery, D M; Fone, K C F; Waddington, J L; Moran, P M

    2013-07-01

    Drugs that induce psychosis, such as D-amphetamine (AMP), and those that alleviate it, such as antipsychotics, are suggested to exert behavioral effects via dopamine receptor D2 (D2). All antipsychotic drugs are D2 antagonists, but D2 antagonism underlies the severe and debilitating side effects of these drugs; it is therefore important to know whether D2 is necessary for their behavioral effects. Using D2-null mice (Drd2-/-), we first investigated whether D2 is required for AMP disruption of latent inhibition (LI). LI is a process of learning to ignore irrelevant stimuli. Disruption of LI by AMP models impaired attention and abnormal salience allocation consequent to dysregulated dopamine relevant to schizophrenia. AMP disruption of LI was seen in both wild-type (WT) and Drd2-/-. This was in contrast to AMP-induced locomotor hyperactivity, which was reduced in Drd2-/-. AMP disruption of LI was attenuated in mice lacking dopamine receptor D1 (Drd1-/-), suggesting that D1 may play a role in AMP disruption of LI. Further supporting this possibility, we found that D1 antagonist SKF83566 attenuated AMP disruption of LI in WT. Remarkably, both haloperidol and clozapine attenuated AMP disruption of LI in Drd2-/-. This demonstrates that antipsychotic drugs can attenuate AMP disruption of learning to ignore irrelevant stimuli in the absence of D2 receptors. Data suggest that D2 is not essential either for AMP to disrupt or for antipsychotic drugs to reverse AMP disruption of learning to ignore irrelevant stimuli and further that D1 merits investigation in the mediation of AMP disruption of these processes.

  16. Selective rescue of selenoprotein expression in mice lacking a highly specialized methyl group in selenocysteine tRNA.

    PubMed

    Carlson, Bradley A; Xu, Xue-Ming; Gladyshev, Vadim N; Hatfield, Dolph L

    2005-02-18

    Selenocysteine (Sec) is the 21st amino acid in the genetic code. Its tRNA is variably methylated on the 2'-O-hydroxyl site of the ribosyl moiety at position 34 (Um34). Herein, we identified a role of Um34 in regulating the expression of some, but not all, selenoproteins. A strain of knock-out transgenic mice was generated, wherein the Sec tRNA gene was replaced with either wild type or mutant Sec tRNA transgenes. The mutant transgene yielded a tRNA that lacked two base modifications, N(6)-isopentenyladenosine at position 37 (i(6)A37) and Um34. Several selenoproteins, including glutathione peroxidases 1 and 3, SelR, and SelT, were not detected in mice rescued with the mutant transgene, whereas other selenoproteins, including thioredoxin reductases 1 and 3 and glutathione peroxidase 4, were expressed in normal or reduced levels. Northern blot analysis suggested that other selenoproteins (e.g. SelW) were also poorly expressed. This novel regulation of protein expression occurred at the level of translation and manifested a tissue-specific pattern. The available data suggest that the Um34 modification has greater influence than the i(6)A37 modification in regulating the expression of various mammalian selenoproteins and Um34 is required for synthesis of several members of this protein class. Many proteins that were poorly rescued appear to be involved in responses to stress, and their expression is also highly dependent on selenium in the diet. Furthermore, their mRNA levels are regulated by selenium and are subject to nonsense-mediated decay. Overall, this study described a novel mechanism of regulation of protein expression by tRNA modification that is in turn regulated by levels of the trace element, selenium.

  17. Sensitive and critical periods in the development of handling induced seizures in mice lacking synapsins: differences between synapsin I and synapsin II knockouts.

    PubMed

    Etholm, Lars; Bahonjic, Elma; Heggelund, Paul

    2013-09-01

    Mice lacking either synapsin I or synapsin II develop handling induced seizures from around two months of age. In mice lacking synapsin I (synapsin 1 knock-out mice, Syn1KO mice) such seizures can either consist of mild myoclonic jerks or of fully developed generalized tonic-clonic seizures, and the two seizure types are quite evenly distributed. In mice lacking synapsin II (synapsin 2 knock-out mice, Syn2KO mice) all seizures are in the form of generalized tonic-clonic seizures. Through the use of specialized animal rearing procedures whereby human-animal interaction was minimized (minimal handling procedures), this study investigated effects of handling also prior to the emergence of actual seizures. The effect of minimal handling procedures was significant in both genotypes, but most pronounced in Syn1KO mice. In this genotype, minimal handling reduced the frequency of mild seizures, and completely eliminated generalized tonic-clonic seizures when the animals were tested with regular handling at 4 1/2 months of age. Neither seizure frequency nor generalized tonic-clonic seizures could be re-established through regular handling from 4 1/2 to 8 months. This suggests that the period up to 4 1/2 months constitute a sensitive period for seizures in general, and a critical period for generalized tonic-clonic seizures in this genotype. In Syn2KO mice minimal handling did not remove generalized tonic-clonic seizures, as such seizures were present when handling was introduced at 4 1/2 months. We found an initial reduction of seizure frequency, but the seizure frequency eventually reached levels seen in mice kept under regular handling regimes. Thus, it is unlikely that the period up to 4 1/2 months is a sensitive period in the Syn2KO genotype. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Lack of B and T lymphocyte attenuator exacerbates autoimmune disorders and induces Fas-independent liver injury in MRL-lpr/lpr mice.

    PubMed

    Oya, Yoshihiro; Watanabe, Norihiko; Kobayashi, Yoshihisa; Owada, Takayoshi; Oki, Mie; Ikeda, Kei; Suto, Akira; Kagami, Shin-ichiro; Hirose, Koichi; Kishimoto, Takashi; Nakajima, Hiroshi

    2011-05-01

    MRL/Mp-Fas (lpr) (MRL-lpr) mice develop a systemic autoimmune disease and are considered to be a good model for systemic lupus erythematosus in humans. We have recently shown that mice lacking B and T lymphocyte attenuator (BTLA), an inhibitory co-receptor expressed mainly on lymphocytes, on a 129SvEv background spontaneously develop lymphocytic infiltration in multiple organs and an autoimmune hepatitis (AIH)-like disease. In this study, we investigated the role of BTLA in the pathogenesis of autoimmune diseases in MRL-lpr mice. We found that BTLA-deficient (BTLA(-/-)) MRL-lpr/lpr mice developed severe lymphocytic infiltration in salivary glands, lungs, pancreas, kidneys and joints as compared with BTLA-sufficient (BTLA(+/+)) MRL-lpr/lpr mice. In addition, although AIH-like disease was not found in BTLA(+/+) MRL-lpr/lpr mice, AIH-like disease was exacerbated in BTLA(-/-) MRL-lpr/lpr mice as compared with that in BTLA(-/-) 129SvEv mice. These results suggest that BTLA plays a protective role in autoimmune diseases in MRL-lpr mice and that AIH-like disease develops in BTLA(-/-) mice even in the absence of Fas-dependent signaling.

  19. Reduced Live Organism Recovery and Lack of Hydrosalpinx in Mice Infected with Plasmid-Free Chlamydia muridarum

    PubMed Central

    Lei, Lei; Chen, Jianlin; Hou, Shuping; Ding, Yiling; Yang, Zhangsheng; Zeng, Hao; Baseman, Joel

    2014-01-01

    Plasmid-free Chlamydia trachomatis and Chlamydia muridarum fail to induce severe pathology. To evaluate whether the attenuated pathogenicity is due to insufficient infection or inability of the plasmidless chlamydial organisms to trigger pathological responses, we compared plasmid-competent and plasmid-free C. muridarum infections in 5 different strains of mice. All 5 strains developed hydrosalpinx following intravaginal inoculation with plasmid-competent, but not inoculation with plasmid-free, C. muridarum. The lack of hydrosalpinx induction by plasmid-free C. muridarum correlated with significantly reduced live organism recovery from the lower genital tract and shortened infection in the upper genital tract. The plasmid-free C. muridarum organisms failed to induce hydrosalpinx even when the organisms were directly inoculated into the oviduct via an intrabursal injection, which was accompanied by significantly reduced survival of the plasmidless organisms in the genital tracts. Furthermore, plasmid-competent C. muridarum organisms after UV inactivation were no longer able to induce hydrosalpinx even when directly delivered into the oviduct at a high dose. Together, these observations suggest that decreased survival of and shortened infection with plasmid-free C. muridarum may contribute significantly to its attenuated pathogenicity. We conclude that adequate live chlamydial infection in the oviduct may be necessary to induce hydrosalpinx. PMID:24343644

  20. Postnatal loss of Merkel cells, but not of slowly adapting mechanoreceptors in mice lacking the neurotrophin receptor p75.

    PubMed

    Kinkelin, I; Stucky, C L; Koltzenburg, M

    1999-11-01

    Merkel cells are specialized epidermal cells which are abundantly found in touch-sensitive areas and which are innervated by slowly adapting mechanosensitive afferent fibres with large myelinated (Abeta) axons. The role of Merkel cells in mechanosensation, their developmental regulation and their influence on sensory neuron function are, however, incompletely understood. Here, we used mice lacking the neurotrophin receptor p75 which is expressed on Merkel cells to investigate their postnatal development and that of their innervating sensory neurons. Using morphological studies we now show that Merkel cells develop normally in both hairy and glabrous skin in these animals until 2 weeks old, but are progressively lost thereafter and have almost completely disappeared 2 months after birth. Using standard extracellular electrophysiological recording techniques we find that despite the profound loss of Merkel cells there is no corresponding reduction in the number of myelinated slowly adapting afferent fibres. Moreover, the mean mechanical threshold of these neurons and their average stimulus response function to suprathreshold mechanical stimuli does not change during the time period when more than 99% of Merkel cells are lost. We conclude that Merkel cells require p75 during the late postnatal development. However, neither the survival nor the mechanical sensitivity of slowly adapting mechanoreceptive Abeta-fibres depends on the presence of Merkel cells.