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Reduced Expression (reduced + expression)
Selected AbstractsReduced Expression of the KATP Channel Subunit, Kir6.2, is Associated with Decreased Expression of Neuropeptide Y and Agouti-Related Protein in the Hypothalami of Zucker Diabetic Fatty RatsJOURNAL OF NEUROENDOCRINOLOGY, Issue 12 2007A. Gyte The link between obesity and diabetes is not fully understood but there is evidence to suggest that hypothalamic signalling pathways may be involved. The hypothalamic neuropeptides, pro-opiomelanocortin (POMC), neuropeptide Y (NPY) and agouti-related protein (AGRP) are central to the regulation of food intake and have been implicated in glucose homeostasis. Therefore, the expression of these genes was quantified in hypothalami from diabetic Zucker fatty (ZDF) rats and nondiabetic Zucker fatty (ZF) rats at 6, 8, 10 and 14 weeks of age. Although both strains are obese, only ZDF rats develop pancreatic degeneration and diabetes over this time period. In both ZF and ZDF rats, POMC gene expression was decreased in obese versus lean rats at all ages. By contrast, although there was the expected increase in both NPY and AGRP expression in obese 14-week-old ZF rats, the expression of NPY and AGRP was decreased in 6-week-old obese ZDF rats with hyperinsulinaemia and in 14-week-old rats with the additional hyperglycaemia. Therefore, candidate genes involved in glucose, and insulin signalling pathways were examined in obese ZDF rats over this age range. We found that expression of the ATP-sensitive potassium (KATP) channel component, Kir6.2, was decreased in obese ZDF rats and was lower compared to ZF rats in each age group tested. Furthermore, immunofluorescence analysis showed that Kir6.2 protein expression was reduced in the dorsomedial and ventromedial hypothalamic nuclei of 6-week-old prediabetic ZDF rats compared to ZF rats. The Kir6.2 immunofluorescence colocalised with NPY throughout the hypothalamus. The differences in Kir6.2 expression in ZF and ZDF rats mimic those of NPY and AGRP, which could infer that the changes occur in the same neurones. Overall, these data suggest that chronic changes in hypothalamic Kir6.2 expression may be associated with the development of hyperinsulinaemia and hyperglycaemia in ZDF rats. [source] Down-regulation of ATBF1 is a major inactivating mechanism in hepatocellular carcinomaHISTOPATHOLOGY, Issue 5 2008C J Kim Aims:, ,-Fetoprotein (AFP) is frequently detected in hepatocellular carcinomas (HCCs) and AT motif binding factor 1 (ATBF1) down-regulates AFP gene expression in hepatic cells. The ATBF1 gene also inhibits cell growth and differentiation, and altered gene expression is associated with malignant transformation. The aim was to investigate the potential role of the ATBF1 gene in HCCs. Methods and results:, Somatic mutations, allelic loss and hypermethylation of the ATBF1 gene were analysed in 76 sporadic HCCs. The level of ATBF-1 mRNA expression was analysed using quantitative real-time reverse transcriptase-polymerase chain reaction. Genetic studies of the ATBF1 gene revealed absence of somatic mutation in the hotspot region and 15 (25%) of 60 informative cases showed allelic loss at the ATBF1 locus. Hypermethylation in the intron 1 region of the ATBF1 gene was detected in only one case. Interestingly, ATBF1 mRNA expression in HCCs was significantly reduced in 55 (72.4%) samples compared with the corresponding surrounding liver tissues. Reduced expression was not statistically associated with clinicopathological parameters including stage, histological grade, infective virus type, and serum ,-fetoprotein level. Conclusions:, The ATBF1 gene may contribute to the development of HCCs via transcriptional down-regulation of mRNA expression, but not by genetic or epigenetic alterations. [source] Reduced expression of MYO18B, a candidate tumor-suppressor gene on chromosome arm 22q, in ovarian cancerINTERNATIONAL JOURNAL OF CANCER, Issue 1 2004Nozomu Yanaihara Abstract Allelic imbalance on chromosome arm 22q has been detected in 50,70% of ovarian cancers, suggesting the presence of a tumor-suppressor gene on this chromosome arm that is involved in ovarian carcinogenesis. Recently, we isolated a candidate tumor-suppressor gene, MYO18B, at 22q12.1, which is deleted, mutated and hypermethylated in approximately 50% of lung cancers. In our study, we analyzed genetic and epigenetic alterations of the MYO18B gene in ovarian cancers. Missense MYO18B mutations were detected in 1 of 4 (25%) ovarian cancer cell lines and in 1 of 17 (5.9%) primary ovarian cancers. MYO18B expression was reduced in all 4 ovarian cancer cell lines and in 12 of 17 (71%) of primary ovarian cancers. MYO18B expression was restored by treatment with 5-aza-2,-deoxycytidine and/or trichostatin A in 3 of 4 cell lines with reduced MYO18B expression, and hypermethylation of the promoter CpG island for MYO18B was observed in 2 of these 3 cell lines. Its hypermethylation was also observed in 2 of 15 (13%) primary ovarian cancers. Thus, it was indicated that MYO18B expression is reduced in a considerable fraction of ovarian cancers by several mechanisms, including hypermethylation, while the MYO18B gene is mutated in a small subset of ovarian cancers. The present results suggest that MYO18B alterations, including both epigenetic and genetic alterations, play an important role in ovarian carcinogenesis. © 2004 Wiley-Liss, Inc. [source] Reduced expression of alpha-1,2-mannosidase I extends lifespan in Drosophila melanogaster and Caenorhabditis elegansAGING CELL, Issue 4 2009Ya-Lin Liu Summary Exposure to sub-lethal levels of stress, or hormesis, was a means to induce longevity. By screening for mutations that enhance resistance to multiple stresses, we identified multiple alleles of alpha-1,2-mannosidase I (mas1) which, in addition to promoting stress resistance, also extended longevity. Longevity enhancement is also observed when mas1 expression is reduced via RNA interference in both Drosophila melanogaster and Caenorhabditis elegans. The screen also identified Edem1 (Edm1), a gene downstream of mas1, as a modulator of lifespan. As double mutants for both mas1 and Edm1 showed no additional longevity enhancement, it appeared that both mutations function within a common pathway to extend lifespan. Molecular analysis of these mutants revealed that the expression of BiP, a putative biomarker of dietary restriction (DR), is down-regulated in response to reductions in mas1 expression. These findings suggested that mutations in mas1 may extend longevity by modulating DR. [source] Reduced expression of MAb6B4 epitopes on chondroitin sulfate proteoglycan aggrecan in perineuronal nets from cerebral cortices of SAMP10 mice: A model for age-dependent neurodegenerationJOURNAL OF NEUROSCIENCE RESEARCH, Issue 6 2008Yuko Saitoh Abstract The accelerated senescence-prone SAMP10 mouse strain is a model for age-dependent neurodegeneration and is characterized by brain atrophy and deficits in learning and memory. Because perineuronal nets play an important role in the synaptic plasticity of adult brains, we examined the distributions of molecules that constitute perineuronal nets in SAMP10 mouse brain samples and compared them with those in control SAMR1 mouse samples. Proteoglycan-related monoclonal antibody 6B4 (MAb6B4) clearly immunostained perineuronal nets in SAMR1 mice cortices, but the corresponding immunostaining in SAMP10 mice was very faint. MAb6B4 recognizes phosphacan/PTP, in immature brains. However, this antibody recognized several protein bands, including a 400-kDa core glycoprotein from chondroitin sulfate proteoglycan in homogenates of mature cortices from SAMR1 mice. The 400-kDa band was also recognized by antiaggrecan antibodies. The aggrecan core glycoprotein band was also detectable in samples from SAMP10 mice, but this glycoprotein was faintly immunostained by MAb6B4. Because MAb6B4 recognized the same set of protein bands that the monoclonal antibody Cat-315 recognized in mature cerebral cortices of SAMR1 mice, the MAb6B4 epitope appears to be closely related to that of Cat-315 and presumably represents a novel type of oligosaccharide that attaches to aggrecans. The Cat-315 epitope colocalized with aggrecan in perineuronal nets from SAMR1 mouse brain samples, whereas its expression was prominently reduced in SAMP10 mouse brain samples. The biological significance of the MAb6B4/Cat-315 epitope in brain function and its relationship to the neurodegeneration and learning disabilities observed in SAMP10 mice remain to be elucidated. © 2007 Wiley-Liss, Inc. [source] Reduced expression of CD9 in oral squamous cell carcinoma: CD9 expression inversely related to high prevalence of lymph node metastasisJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 2 2001Jingo Kusukawa Abstract: Because CD9 is implicated in cell growth, cell adhesion and cell motility, altered CD9 expression might be involved in cancer invasion and metastasis. We have studied the immunolocalization of CD9 in oral squamous cell carcinoma (SCC). Sections prepared from paraffin-embedded specimens from patients with SCC of the oral cavity were stained with a monoclonal anti-CD9 antibody by means of the streptoavidin biotin method. Significant reduction or complete loss of CD9 expression was observed in cancer cells at the periphery of the cancer nests in the advancing front of invading tumor. Among 78 cases of oral SCCs examined, 46 (59.0%) cases were completely negative for CD9 expression. Loss of CD9 expression in cancer tissue strongly correlated with a high incidence of cervical lymph node metastasis and poorer prognosis (P=0.001). Thus a close examination of CD9 in SCC tissue would be useful for the prognosis of patients with oral carcinoma. [source] Reduced expression of the Rassf1a gene and its aberrant DNA methylation in pancreatic duct adenocarcinomas induced by N-nitrosobis(2-oxopropyl)amine in hamstersMOLECULAR CARCINOGENESIS, Issue 2 2008Kyoko Shimizu Abstract Alterations of the Rassf1a gene were investigated in pancreatic duct adenocarcinomas (PDAs) induced by N-nitrosobis(2-oxopropyl)amine (BOP) in hamsters. Female Syrian golden hamsters received 70 mg/kg BOP, followed by repeated exposures to an augmentation pressure regimen consisting of a choline-deficient diet combined with a sequential course of DL -ethionine, L -methionine, and 20 mg/kg BOP. A total of 15 PDAs were obtained, and total RNAs were assessed by real-time quantitative reverse transcription (RT)-polymerase chain reaction (PCR). Expression of the Rassf1a was significantly reduced in PDAs (P,<,0.005) compared with normal pancreatic tissues. For analysis of methylation status, bisulfite sequencing was performed. Normal tissues were all unmethylated in the 5, upstream region of Rassf1a. In contrast, four PDAs were highly methylated, correlating with reduced expression of the Rassf1a gene. Using reverse transcription (RT)-polymerase chain reaction (PCR)-single strand conformation polymorphism (SSCP) analysis, mutations were detected in 3 out of 15 PDAs (20%). These results suggested that alterations of the Rassf1a gene may be involved in development of PDAs induced by BOP in hamsters. © 2007 Wiley-Liss, Inc. [source] Staphylococcus aureus SigB activity promotes a strong fibronectin,bacterium interaction which may sustain host tissue colonization by small-colony variants isolated from cystic fibrosis patientsMOLECULAR MICROBIOLOGY, Issue 6 2008Gabriel Mitchell Summary Genes encoding cell-surface proteins regulated by SigB are stably expressed in Staphylococcus aureus small-colony variants (SCVs) isolated from cystic fibrosis (CF) patients. Our hypothesis is that CF-isolated SCVs are locked into a colonization state by sustaining the expression of adhesins such as fibronectin-binding proteins (FnBPs) throughout growth. Force spectroscopy was used to study the fibronectin,FnBPs interaction among strains varying for their SigB activity. The fibronectin,FnBPs interaction was described by a strength of 1000 ± 400 pN (pulling rate of 2 ,m s,1), an energetic barrier width of 0.6 ± 0.1 Å and an off-rate below 2 × 10,4 s,1. A CF-isolated SCV highly expressed fnbA throughout growth and showed a sustained capacity to bind fibronectin, whereas a prototypic strain showed a reduced frequency of fibronectin-binding during the stationary growth phase when its fnbA gene was down-regulated. Reduced expression of fnbA was observed in sigB mutants, which was associated with an overall decrease adhesion to fibronectin. These results suggest that the fibronectin,FnBPs interaction plays a role in the formation of a mechanically resistant adhesion of S. aureus to host tissues and supports the hypothesis that CF-isolated SCVs are locked into a colonization state as a result of a sustained SigB activity. [source] Malignant transformation of mature cystic teratoma to squamous cell carcinoma involves altered expression of p53- and p16/Rb-dependent cell cycle regulator proteinsPATHOLOGY INTERNATIONAL, Issue 12 2008Atsuko Iwasa Ovarian mature cystic teratomas (MCT) uncommonly undergo malignant transformation to squamous cell carcinoma (SCC). While alterations in the p53 tumor suppressor gene and protein have been shown, few studies have analyzed other molecular changes leading to this malignant conversion. The purpose of the present study was to investigate 21 samples of SCC arising in MCT for altered expression in known p53- and p16/Rb-dependent cell cycle regulatory proteins, and the association between their expression and cellular proliferation and histological features. Overexpression of the p53 protein was observed in 14 SCC (67%), while four (19%) had point mutations in the p53 gene. Reduced expression of the p16 protein was observed in 18 SCC (86%), while p16 gene alterations (hypermethylation (29%) and point mutation (33%)) were found in 11 (52%). Furthermore, a statistically significant correlation was observed between p53 and Rb overexpression (P = 0.0010), and the overexpression of both p53 and Rb was respectively significantly correlated with increased cellular proliferation. The results indicate that alterations in both the p53 and p16-Rb pathways are associated with SCC arising in MCT. [source] Immunohistochemical study of the expression of adhesion molecules in ovarian serous neoplasmsPATHOLOGY INTERNATIONAL, Issue 2 2006Eun Yoon Cho To clarify possible roles of adhesion molecules including E-cadherin, ,- and ,-catenin, CD44s, CD44v6, CD56, and CD99 in ovarian serous neoplasms, an immunohistochemical study was undertaken for 23 benign, 40 borderline, and 95 malignant ovarian serous neoplasms using tissue microarray (TMA). Significantly reduced expression of E-cadherin, and overexpression of CD44s, CD56, and CD99 were more frequently observed in adenocarcinomas than in benign and borderline tumors. Expression of CD44v6 and nuclear ,- and ,-catenin were detected only in borderline tumors and adenocarcinomas. Reduced expression of E-cadherin was also correlated with high tumor grade (P = 0.03), presence of peritoneal seeding (P = 0.03), and low overall survival rate (P = 0.02). Overexpression of CD44s was significantly associated with high tumor grade (P = 0.04), advanced stage (P = 0.03), and low overall survival rate (P = 0.02). CD56 was increasingly expressed in the case of advanced stage (P = 0.005) and peritoneal seeding (P = 0.001). Nuclear staining for ,-catenin was correlated with tumor progression (P = 0.004) and advanced International Federation of Gynecology and Obstetrics (FIGO) stage (P = 0.02). Only CD44s expression and stage were correlated with overall survival in multivariate study. These results suggest that although E-cadherin, CD44s, CD56, and nuclear ,-catenin immunoexpression seem to be useful prognostic markers for serous neoplasm of the ovary, CD44s expression and FIGO stage are independent prognostic factors. [source] Reduced expression and novel splice variants of ING4 in human gastric adenocarcinoma,THE JOURNAL OF PATHOLOGY, Issue 1 2009Ming Li Abstract ING4, a new member of the ING (inhibitor of growth) family of tumour suppressor genes, has been found to be deleted or down-regulated in gliomas, breast tumours, and head and neck squamous cell carcinomas. The goal of the present study was to investigate whether the expression and alternative splicing of ING4 transcripts are involved in the initiation and progression of stomach adenocarcinoma. ING4 mRNA and protein expression was examined in gastric adenocarcinoma tissues and human gastric adenocarcinoma cell lines by RT-PCR, real-time RT-PCR, tissue microarray immunohistochemistry, and western blot analysis. Alterations in ING4 transcripts were determined through sequence analysis of ING4 cDNA. Our data showed that ING4 mRNA and protein were dramatically reduced in stomach adenocarcinoma cell lines and tissues, and significantly less in female than in male patients. We also found that reduced ING4 mRNA expression correlated with the stage of the tumour. Interestingly, by sequence analysis, we discovered five novel aberrantly spliced variant forms of ING4_v1 and ING4_v2. These variants cause a codon frame-shift and, eventually, deletion of the NLS or PHD domain contributing to the mislocalization of p53 and/or HAT/HDAC complexes and, subsequently, altered gene expression in gastric adenocarcinoma. These results suggest that attenuated and aberrant ING4 expression may be involved in the initiation and progression of stomach adenocarcinoma. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [source] The Arabidopsis ARGOS-LIKE gene regulates cell expansion during organ growthTHE PLANT JOURNAL, Issue 1 2006Yuxin Hu Summary Cell expansion, and its coordination with cell division, plays a critical role in the growth and development of plant organs. However, the genes controlling cell expansion during organogenesis are largely unknown. Here, we demonstrate that a novel Arabidopsis gene, ARGOS-LIKE (ARL), which has some sequence homology to the ARGOS gene, is involved in this process. Reduced expression or overexpression of ARL in Arabidopsis results in smaller or larger cotyledons and leaves as well as other lateral organs, respectively. Anatomical examination of cotyledons and leaves in ARL transgenic plants demonstrates that the alteration in size can be attributed to changes in cell size rather than cell number, indicating that ARL plays a role in cell expansion-dependent organ growth. ARL is upregulated by brassinosteroid (BR) and this induction is impaired in the BR-insensitive mutant bri1, but not in the BR-deficient mutant det2. Ectopic expression of ARL in bri1,119 partially restores cell growth in cotyledons and leaves. Our results suggest that ARL acts downstream of BRI1 and partially mediates BR-related cell expansion signals during organ growth. [source] Apoptosis regulators Fau and Bcl-G are down-regulated in prostate cancerTHE PROSTATE, Issue 14 2010Mark R. Pickard Abstract BACKGROUND The molecular control of cell death through apoptosis is compromised in prostate cancer cells, resulting in inappropriate cell survival and resistance to cytotoxic therapy. Reduced expression of the functionally connected apoptosis-regulators and candidate tumor suppressors Fau and Bcl-G has recently been implicated in oncogenesis in other tissues. The present study examines the hypothesis that reduced expression of these genes may be involved in prostate cancer. METHODS Fau and Bcl-G mRNA levels were determined by real time RT-PCR in two independent prostate tissue collections. In experiments in vitro, Fau and Bcl-G levels in prostate cancer cell lines were reduced using RNA interference and the effects on sensitivity to UVC irradiation were determined. RESULTS Fau and Bcl-G mRNA levels were both lower in prostate cancer tissue than in normal prostate and Benign Prostate Hyperplasia. Active down-regulation of Fau and Bcl-G expression in vitro resulted in decreased sensitivity to UVC-induced cytotoxicity. Simultaneous down-regulation of Fau and Bcl-G produced a decrease in sensitivity which was similar to either gene alone. CONCLUSIONS Fau and Bcl-G mRNA levels are both decreased in prostate cancer. In prostate cancer cell lines in vitro such down-regulation results in reduced sensitivity to UVC-induced cytotoxicity, consistent with the putative roles of these genes as candidate prostate tumor suppressors. The absence of an additive effect when Fau and Bcl-G were down-regulated simultaneously is consistent with the two genes acting in the same apoptosis pathway, for example, with the pro-apoptotic effects of Fau being mediated through modulation of Bcl-G. Prostate 70: 1513,1523, 2010. © 2010 Wiley-Liss, Inc. [source] Reduced expression of nicotinic , subunits 3, 7, 9 and 10 in lesional and nonlesional atopic dermatitis skin but enhanced expression of , subunits 3 and 5 in mast cellsBRITISH JOURNAL OF DERMATOLOGY, Issue 4 2008F. Kindt Summary Background, The skin cholinergic signalling system is modulated in atopic dermatitis (AD). Objectives, To investigate of the role of nicotinic acetylcholine receptors (nAChRs) in the pathogenesis of AD. Methods, We investigated the expression and localization of nAChR , subunits in AD by quantitative reverse transcription-polymerase chain reaction and immunohistochemistry of biopsies from lesional and nonlesional areas of AD skin and of skin biopsies from healthy control persons. Results, Our data demonstrate the presence of mRNA and protein of the nAChR , subunits 3, 5, 7, 9 and 10 in keratinocytes and mast cells in healthy and AD skin. Expression of the , subunits 3, 7, 9 and 10 was generally reduced in the skin of patients with AD whereas mast cells in AD but not in healthy skin showed ,3 and ,5 subunit immunoreactivity. Differences in the subunit mRNA levels between lesional and nonlesional skin were obtained for the , subunits 3, 9 and 10 with higher levels of ,3 but lower levels of ,10 subunit mRNA in lesional areas. No differences in the expression of the , subunits was found between the groups of extrinsic, intrinsic or mixed AD types, between genders and between smokers and nonsmokers. Conclusions, This supports the idea that the cholinergic system is dysregulated independently from inflammation in AD and that inflammation further modulates individual nAChR subunits. [source] SunB, a novel Sad1 and UNC-84 domain-containing protein required for development of Dictyostelium discoideumDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 7 2010Nao Shimada A gene, sunB, encoding a novel class of Sad1 and UNC-84 (SUN) domain, was isolated from a cDNA screen for suppressors of a mutation in Dd-STATa , a Dictyostelium homologue of metazoan STAT (signal transducers and activators of transcription). The SunB protein localized in the area around the nucleus in growing cells, but in the multicellular stages it was predominantly found in prespore vacuoles (PSVs). A disruptant of sunB was multinucleated in the vegetative phase; during development it formed mounds with multiple tips and failed to culminate. The mutation was cell autonomous, and showed reduced expression of the prespore marker gene pspA and elevated expression of marker genes for prestalk AB cells. Interestingly, the level of SunB was abnormally high in the prestalk cells of Dd-STATa mutants, which are defective in culmination. We conclude that SunB is essential for accurate prestalk/prespore differentiation during Dictyostelium development and that its cell-type dependent localization is regulated by a Dd-STATa-mediated signaling pathway. [source] Blocking Dishevelled signaling in the noncanonical Wnt pathway in sea urchins disrupts endoderm formation and spiculogenesis, but not secondary mesoderm formationDEVELOPMENTAL DYNAMICS, Issue 7 2009Christine A. Byrum Abstract Dishevelled (Dsh) is a phosphoprotein key to beta-catenin dependent (canonical) and beta-catenin independent (noncanonical) Wnt signaling. Whereas canonical Wnt signaling has been intensively studied in sea urchin development, little is known about other Wnt pathways. To examine roles of these beta-catenin independent pathways in embryogenesis, we used Dsh-DEP, a deletion construct blocking planar cell polarity (PCP) and Wnt/Ca2+ signaling. Embryos overexpressing Dsh-DEP failed to gastrulate or undergo skeletogenesis, but produced pigment cells. Although early mesodermal gene expression was largely unperturbed, embryos exhibited reduced expression of genes regulating endoderm specification and differentiation. Overexpressing activated beta-catenin failed to rescue Dsh-DEP embryos, indicating that Dsh-DEP blocks endoderm formation downstream of initial canonical Wnt signaling. Because Dsh-DEP-like constructs block PCP signaling in other metazoans, and disrupting RhoA or Fz 5/8 in echinoids blocks subsets of the Dsh-DEP phenotypes, our data suggest that noncanonical Wnt signaling is crucial for sea urchin endoderm formation and skeletogenesis. Developmental Dynamics 238:1649,1665, 2009. © 2009 Wiley-Liss, Inc. [source] HOXA13 directly regulates EphA6 and EphA7 expression in the genital tubercle vascular endotheliaDEVELOPMENTAL DYNAMICS, Issue 4 2007Carley A. Shaut Abstract Hypospadias, a common defect affecting the growth and closure of the external genitalia, is often accompanied by gross enlargements of the genital tubercle (GT) vasculature. Because Hoxa13 homozygous mutant mice also exhibit hypospadias and GT vessel expansion, we examined whether genes playing a role in angiogenesis exhibit reduced expression in the GT. From this analysis, reductions in EphA6 and EphA7 were detected. Characterization of EphA6 and EphA7 expression in the GT confirmed colocalization with HOXA13 in the GT vascular endothelia. Analysis of the EphA6 and EphA7 promoter regions revealed a series of highly conserved cis -regulatory elements bound by HOXA13 with high affinity. GT chromatin immunoprecipitation confirmed that HOXA13 binds these gene-regulatory elements in vivo. In vitro, HOXA13 activates gene expression through the EphA6 and EphA7 gene-regulatory elements. Together these findings indicate that HOXA13 directly regulates EphA6 and EphA7 in the developing GT and identifies the GT vascular endothelia as a novel site for HOXA13-dependent expression of EphA6 and EphA7. Developmental Dynamics 236:951,960, 2007. © 2007 Wiley-Liss, Inc. [source] Maternal hypoxia increases the activity of MMPs and decreases the expression of TIMPs in the brain of neonatal ratsDEVELOPMENTAL NEUROBIOLOGY, Issue 3 2010Wenni Tong Abstract A recent study has shown that increased activity of matrix metalloproteinases-2 and metalloproteinases-9 (MMP-2 and MMP-9) has detrimental effect on the brain after neonatal hypoxia. The present study determined the effect of maternal hypoxia on neuronal survivability and the activity of MMP-2 and MMP-9, as well as the expression of tissue inhibitors of metalloproteinase 1 and 2 (TIMP-1 and TIMP-2) in the brain of neonatal rats. Pregnant rats were exposed to 10.5% oxygen for 6 days from the gestation day 15 to day 21. Pups were sacrificed at day 0, 4, 7, 14, and 21 after birth. Body weight and brain weight of the pups were measured at each time point. The activity of MMP-2 and MMP-9 and the protein abundance of TIMP-1 and TIMP-2 were determined by zymography and Western blotting, respectively. The tissue distribution of MMPs was examined by immunofluorescence staining. The neuronal death was detected by Nissl staining. Maternal hypoxia caused significant decreases in body and brain size, increased activity of MMP-2 at day 0, and increased MMP-9 at day 0 and 4. The increased activity of the MMPs was accompanied by an overall tendency towards a reduced expression of TIMPs at all ages with the significance observed for TIMPs at day 0, 4, and 7. Immunofluorescence analysis showed an increased expression of MMP-2, MMP-9 in the hippocampus at day 0 and 4. Nissl staining revealed significant cell death in the hippocampus at day 0, 4, and 7. Functional tests showed worse neurobehavioral outcomes in the hypoxic animals. © 2009 Wiley Periodicals, Inc. Develop Neurobiol 2010 [source] L1, ,1 integrin, and cadherins mediate axonal regeneration in the embryonic spinal cordDEVELOPMENTAL NEUROBIOLOGY, Issue 14 2006Murray Blackmore Abstract Embryonic birds and mammals are capable of axon regeneration after spinal cord injury, but this ability is lost during a discrete developmental transition. We recently showed that changes within maturing neurons, as opposed to changes solely in the spinal cord environment, significantly restrict axon regeneration during development. The developmental changes within neurons that limit axon regeneration remain unclear. One gap in knowledge is the identity of the adhesive receptors that embryonic neurons use to extend axons in the spinal cord. Here we test the roles of L1/NgCAM, ,1 integrin, and cadherins, using a coculture system in which embryonic chick brainstem neurons regenerate axons into an explant of embryonic spinal cord. By in vivo and in vitro methods, we found that brainstem neurons reduce axonal expression of L1 as they mature. Disrupting either L1 or ,1 integrin function individually in our coculture system partially inhibited growth of brainstem axons in spinal cords, while disrupting cadherin function alone had no effect. However, when all three adhesive receptors were blocked simultaneously, axon growth in the spinal cord was reduced by 90%. Using immunohistochemistry and in situ hybridization we show that during the period when neurons lose their regenerative capacity they reduce expression of mRNA for N-cadherin, and reduce axonal L1/NgCAM protein through a post-transcriptional mechanism. These data show that embryonic neurons use L1/NgCAM, ,1 integrin, and cadherin receptors for axon regeneration in the embryonic spinal cord, and raise the possibility that a reduced expression of these essential receptors may contribute to the low-regenerative capacity of older neurons. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006 [source] WAG/Rij rats show a reduced expression of CB1 receptors in thalamic nuclei and respond to the CB1 receptor agonist, R(+)WIN55,212-2, with a reduced incidence of spike-wave dischargesEPILEPSIA, Issue 8 2010Clementina M. Van Rijn Summary Purpose:, Genetically epileptic WAG/Rij rats develop spontaneous absence-like seizures after 3 months of age. We used WAG/Rij rats to examine whether absence seizures are associated with changes in the expression of type-1 cannabinoid (CB1) receptors. Methods:, Receptor expression was examined by in situ hybridization and western blot analysis in various brain regions of "presymptomatic" 2-month old and "symptomatic" 8-month-old WAG/Rij rats relative to age-matched nonepileptic control rats. Furthermore, we examined whether pharmacologic activation of CB1 receptor affects absence seizures. We recorded spontaneous spike-wave discharges (SWDs) in 8-month old WAG/Rij rats systemically injected with the potent CB1 receptor agonist, R(+)WIN55,212-2 (3,12 mg/kg, s.c.), given alone or combined with the CB1 receptor antagonist/inverse agonist, AM251 (12 mg/kg, s.c.). Results:, Data showed a reduction of CB1 receptor mRNA and protein levels in the reticular thalamic nucleus, and a reduction in CB1 receptor protein levels in ventral basal thalamic nuclei of 8-month-old WAG/Rij rats, as compared with age-matched ACI control rats. In vivo, R(+)WIN55,212-2 caused a dose-dependent reduction in the frequency of SWDs in the first 3 h after the injection. This was followed by a late increase in the mean SWD duration, which suggests a biphasic modulation of SWDs by CB1 receptor agonists. Both effects were reversed or attenuated when R(+)WIN55,212-2 was combined with AM251. Discussion:, These data indicate that the development of absence seizures is associated with plastic modifications of CB1 receptors within the thalamic-cortical-thalamic network, and raise the interesting possibility that CB1 receptors are targeted by novel antiabsence drugs. [source] CD4+ T cell help improves CD8+ T cell memory by retained CD27 expressionEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 7 2008Matthias Abstract CD4+ T cell help during the priming of CD8+ T lymphocytes imprints the capacity for optimal secondary expansion upon re-encounter with antigen. Helped memory CD8+ T cells rapidly expand in response to a secondary antigen exposure, even in the absence of T cell help and, are most efficient in protection against a re-infection. In contrast, helpless memory CTL can mediate effector function, but secondary expansion is reduced. How CD4+ T cells instruct CD8+ memory T cells during priming to undergo efficient secondary expansion has not been resolved in detail. Here, we show that memory CTL after infection with lymphocytic choriomeningitis virus are CD27high whereas memory CTL primed in the absence of CD4+ T cell have a reduced expression of CD27. Helpless memory CTL produced low amounts of IL-2 and did not efficiently expand after restimulation with peptide in vitro. Blocking experiments with monoclonal antibodies and the use of CD27,/, memory CTL revealed that CD27 ligation during restimulation increased autocrine IL-2 production and secondary expansion. Therefore, regulating CD27 expression on memory CTL is a novel mechanism how CD4+ T cells control CTL memory. [source] Modulation of dendritic cell phenotype and functionin an in vitro model of the intestinal epitheliumEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 4 2006Matt Butler Abstract A network of dendritic cells (DC) can be detected in close proximity to the epithelial cells overlying Peyer's patches in the gut. Intestinal DC show distinct phenotypes as compared to DC from the systemic lymph nodes (relatively low MHC and costimulatory molecules and high IL-10 and TGF,) and may play a role in maintaining tolerance to enteric antigens. We show that a similar phenotype is induced in the presence of a polarised epithelial cell monolayer in vitro. Monocyte-derived DC were co-cultured with Caco-2 intestinal epithelial monolayers for 24,h. Co-culture resulted in DC with reduced expression of MHC class,II, CD86, and CD80, and poor T,cell stimulatory capacity. Cytokine profiles showed reduced levels of inflammatory cytokine production, and co-cultured DC were less sensitive to stimulation via Toll-like receptors (TLR2, 4, and 6) as a result of increased levels of autocrine TGF, production. However, phenotypic changes in co-cultured DC could not be blocked by removal of apoptotic cells or addition of anti-TGF, antibodies, suggesting that other soluble factors are involved in DC modulation. Thus, polarised epithelial cell monolayers create a ,tolerogenic' environment which modulates the activity of DC. These results highlight the regulatory importance of the epithelial microenvironment at mucosal surfaces. [source] Inactivation of astroglial NF-,B promotes survival of retinal neurons following ischemic injuryEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2009Galina Dvoriantchikova Abstract Reactive astrocytes have been implicated in neuronal loss following ischemic stroke. However, the molecular mechanisms associated with this process are yet to be fully elucidated. In this work, we tested the hypothesis that astroglial NF-,B, a key regulator of inflammatory responses, is a contributor to neuronal death following ischemic injury. We compared neuronal survival in the ganglion cell layer (GCL) after retinal ischemia-reperfusion in wild-type (WT) and in GFAP-I,B,-dn transgenic mice, where the NF-,B classical pathway is suppressed specifically in astrocytes. The GFAP-I,B,-dn mice showed significantly increased survival of neurons in the GCL following ischemic injury as compared with WT littermates. Neuroprotection was associated with significantly reduced expression of pro-inflammatory genes, encoding Tnf-,, Ccl2 (Mcp1), Cxcl10 (IP10), Icam1, Vcam1, several subunits of NADPH oxidase and NO-synthase in the retinas of GFAP-I,B,-dn mice. These data suggest that certain NF-,B-regulated pro-inflammatory and redox-active pathways are central to glial neurotoxicity induced by ischemic injury. The inhibition of these pathways in astrocytes may represent a feasible neuroprotective strategy for retinal ischemia and stroke. [source] Involvement of mitochondrial signaling pathways in the mechanism of Fas-mediated apoptosis after spinal cord injuryEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2009Wen Ru Yu Abstract Activation of the Fas receptor has been recently linked to apoptotic cell death after spinal cord injury (SCI). Although it is generally considered that Fas activation mediates apoptosis predominantly through the extrinsic pathway, we hypothesized that intrinsic mitochondrial signaling could be involved in the underlying mechanism of Fas-induced apoptosis after SCI. In the present study, we utilized the FejotaTM clip compression model of SCI at T5,6 in C57BL/6 Fas-deficient (lpr) and wild-type mice. Complementary studies were conducted using an in vitro model of trauma or a Fas-activating antibody to induce apoptosis in primary neuronal,glial mixed spinal cord cultures. After in vivo SCI, lpr mice, in comparison with wild-type mice, exhibited reduced numbers of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells at the lesion, reduced expression of truncation of Bid (tBid), apoptosis-inducing factor, activated caspase-9 and activated caspase-3, and increased expression of the antiapoptotic proteins Bcl-2 and Bcl-xL. After in vitro neurotrauma or the induction of Fas signaling by the Jo2 activating antibody, lpr spinal cord cultures showed an increased proportion of cells retaining mitochondrial membrane integrity and a reduction of tBid expression, caspase-9 and caspase-3 activation, and TUNEL-positive cells as compared to wild-type spinal cord cultures. The neutralization of Fas ligand (FasL) protected against traumatically induced or Fas-mediated caspase-3 activation and the loss of mitochondrial membrane potential and tBid expression in wild-type spinal cord cultures. However, in lpr spinal cord cultures, FasL neutralization had no protective effects. In summary, these data provide direct evidence for the induction of intrinsic mitochondrial signaling pathways following Fas activation after SCI. [source] Sodium lauryl sulphate alters the mRNA expression of lipid-metabolizing enzymes and PPAR signalling in normal human skin in vivoEXPERIMENTAL DERMATOLOGY, Issue 12 2009Hans Törmä Abstract:, Detergents irritate skin and affect skin barrier homeostasis. In this study, healthy skin was exposed to 1% sodium lauryl sulphate (SLS) in water for 24 h. Biopsies were taken 6 h to 8 days post exposure. Lipid patterns were stained in situ and real-time polymerase chain reaction (PCR) was used to examine mRNA expression of enzymes synthesizing barrier lipids, peroxisome proliferator-activated receptors (PPAR) and lipoxygenases. The lipid pattern was disorganized from 6 h to 3 days after SLS exposure. Concomitant changes in mRNA expression included: (i) reduction, followed by induction, of ceramide-generating ,-glucocerebrosidase, (ii) increase on day 1 of two other enzymes for ceramide biosynthesis and (iii) persistent reduction of acetyl-CoA carboxylase-B, a key enzyme in fatty acid synthesis. Surprisingly, the rate-limiting enzyme in cholesterol synthesis, HMG-CoA reductase, was unaltered. Among putative regulators of barrier lipids synthesis, PPAR, and PPAR, exhibited reduced mRNA expression, while PPAR,/, and LXR, were unaltered. Epidermal lipoxygenase-3, which may generate PPAR, agonists, exhibited reduced expression. In conclusion, SLS induces reorganization of lipids in the stratum corneum, which play a role in detergents' destruction of the barrier. The changes in mRNA expression of enzymes involved in synthesizing barrier lipids are probably important for the restoration of the barrier. [source] Integrated genomic profiling identifies candidate genes implicated in glioma-genesis and a novel LEO1 - SLC12A1 fusion geneGENES, CHROMOSOMES AND CANCER, Issue 6 2010Linda B. C. Bralten We performed genotyping and exon-level expression profiling on 21 glioblastomas (GBMs) and 19 oligodendrogliomas (ODs) to identify genes involved in glioma initiation and/or progression. Low-copy number amplifications (2.5 < n < 7) and high-copy number amplifications (n > 7) were more frequently observed in GBMs; ODs generally have more heterozygous deletions per tumor. Four high-copy amplicons were identified in more than one sample and resulted in overexpression of the known oncogenes EGFR, MDM2, and CDK4. In the fourth amplicon, RBBP5, a member of the RB pathway, may act as a novel oncogene in GBMs. Not all hCNAs contain known genes, which may suggest that other transcriptional and/or regulatory elements are the target for amplification. Regions with most frequent allelic loss, both in ODs and GBMs, resulted in a reduced expression of known tumor suppressor genes. We identified a homozygous deletion spanning the Pragmin gene in one sample, but direct sequencing of all coding exons in 20 other glioma samples failed to detect additional genetic changes. Finally, we screened for fusion genes by identifying aberrant 5,-3, expression of genes that lie over regions of a copy number change. A fusion gene between exon 11 of LEO1 and exon 10 of SLC12A1 was identified. Our data show that integrated genomic profiling can identify genes involved in tumor initiation, and/or progression and can be used as an approach to identify novel fusion genes. © 2010 Wiley-Liss, Inc. [source] Impaired efflux of cholesterol from aged cells and its molecular mechanism: A basis for age-related enhancement of atherosclerosisGERIATRICS & GERONTOLOGY INTERNATIONAL, Issue 3 2007Shizuya Yamashita Aging is one of the risk factors for atherosclerotic cardiovascular diseases, however, its molecular mechanism is currently unknown. Many types of cells in the atherosclerotic lesions are considered to have various biological abnormalities such as impaired lipid homeostasis and slow cell proliferation, which may be related to senescence at cellular levels. One of the common characteristics of senescent cells in vitro is the alteration of actin cytoskeletons, which were reported to be involved in the intracellular transport of lipids. Cholesterol efflux from the cells is the initial step of reverse cholesterol transport, a major protective system against atherosclerosis. Recently, we demonstrated that Cdc42, a member of the Rho -GTPase family, might be crucial for cellular lipid transport and cholesterol efflux based upon studies of Tangier cells that are deficient in ABCA1 gene. In the current review, we also indicate that the expression of Cdc42 is decreased in the cells from aged subjects in close association with the retarded intracellular lipid transport. Furthermore, the Cdc42 expression is reduced by culturing fibroblasts in vitro for a long duration. Werner syndrome (WS) is characterized by the early onset of senescent phenotypes including premature atherosclerotic cardiovascular diseases, although the underlying molecular mechanism for the enhanced atherosclerosis has not been fully understood yet. We examined the intracellular lipid transport and cholesterol efflux and the expression levels of cholesterol efflux-related molecules in skin fibroblasts obtained from patients with WS. Cholesterol efflux was markedly reduced in the WS fibroblasts in association with an increased cellular cholesterol content. Fluorescent recovery after photobleaching technique revealed that intracellular lipid transport around Golgi apparatus was markedly reduced when using a C6-NBD-ceramide as a tracer. Cdc42 protein and its guanosine 5,-triphosphate-bound active form were markedly reduced in the WS fibroblasts. The adenovirus-mediated complementation of wild-type Cdc42 corrected the impaired cholesterol efflux, intracellular lipid transport and cellular cholesterol levels in the WS fibroblasts. These data indicate that the reduced expression of Cdc42 might be responsible for the abnormal lipid transport, which in turn might be related to the accelerated cardiovascular manifestations in WS patients. The current review focuses on the impaired efflux of cholesterol from aged cells and its molecular mechanism as a basis for age-related enhancement of atherosclerosis. [source] Loss of signal transducer and activator of transcription 5 leads to hepatosteatosis and impaired liver regeneration,HEPATOLOGY, Issue 2 2007Yongzhi Cui Growth hormone controls many facets of a cell's biology through the transcription factors Stat5a and Stat5b (Stat5). However, whole body deletion of these genes from the mouse does not provide portentous information on cell-specific cytokine signaling. To explore liver-specific functions of Stat5, the entire Stat5 locus was deleted in hepatocytes using Cre-mediated recombination. Notably, Stat5-mutant mice developed fatty livers and displayed impaired proliferation of hepatocytes upon partial hepatectomy (PHx). Loss of Stat5 led to molecular consequences beyond the reduced expression of Stat5 target genes, such as those encoding suppressor of cytokine signaling 2 (SOCS2), Cish, and insulin-like growth factor 1 (IGF-1). In particular, circulating growth hormone levels were increased and correlated with insulin resistance and increased insulin levels. Aberrant growth hormone (GH)-induced activation of the transcription factors Stat1 and Stat3 was observed in mutant livers. To test whether some of the defects observed in liver-specific Stat5 deficient mice were due to aberrant Stat1 expression and activation, we generated Stat1,/, mice with a hepatocyte-specific deletion of Stat5. Concomitant loss of both Stat5 and Stat1 restored cell proliferation upon PHx but did not reverse fatty liver development. Thus the molecular underpinnings of some defects observed in the absence of Stat5 are the consequence of a deregulated activation of other signal transducers and activators of transcription (STAT) family members. Conclusion: Aberrant cytokine-Stat5 signaling in hepatocytes alters their physiology through increased activity of Stat1 and Stat3. Such cross-talk between different pathways could add to the complexity of syndromes observed in disease. (HEPATOLOGY 2007.) [source] Synergistic premalignant effects of chronic ethanol exposure and insulin receptor substrate-1 overexpression in liverHEPATOLOGY RESEARCH, Issue 9 2008Lisa Longato Aim:, Insulin receptor substrate, type 1 (IRS-1) transmits growth and survival signals, and is overexpressed in more than 90% of hepatocellular carcinomas (HCCs). However, experimental overexpression of IRS-1 in the liver was found not to be sufficient to cause HCC. Since chronic alcohol abuse is a risk factor for HCC, we evaluated potential interactions between IRS-1 overexpression and chronic ethanol exposure by assessing premalignant alterations in gene expression. Methods:, Wild-type (wt) or IRS-1 transgenic (Tg) mice, constitutively overexpressing the human (h) transgene in the liver, were pair-fed isocaloric liquid diets containing 0% or 24% ethanol for 8 weeks. The livers were used for histopathologic study and gene expression analysis, focusing on insulin, insulin-like growth factor (IGF) and wingless (WNT),Frizzled (FZD) pathways, given their known roles in HCC. Results:, In wt mice, chronic ethanol exposure caused hepatocellular microsteatosis with focal chronic inflammation, reduced expression of proliferating cell nuclear antigen (PCNA) and increased expression of IGF-I and IGF-I receptor. In hIRS-1 Tg mice, chronic ethanol exposure caused hepatic micro- and macrosteatosis, focal chronic inflammation, apoptosis and disordered lobular architecture. These effects of ethanol in hIRS-1 Tg mice were associated with significantly increased expression of IGF-II, insulin, IRS-4, aspartyl,asparaginyl , hydroxylase (AAH), WNT-1 and FZD 7, as occurs in HCC. Conclusion:, In otherwise normal liver, chronic ethanol exposure mainly causes liver injury and inflammation with impaired DNA synthesis. In contrast, in the context of hIRS-1 overexpression, chronic ethanol exposure may serve as a cofactor in the pathogenesis of HCC by promoting expression of growth factors, receptors and signaling molecules known to be associated with hepatocellular transformation. [source] Annexin A1 subcellular expression in laryngeal squamous cell carcinomaHISTOPATHOLOGY, Issue 6 2008V A F Alves Aims:, Annexin A1 (ANXA1) is a soluble cytoplasmic protein, moving to membranes when calcium levels are elevated. ANXA1 has also been shown to move to the nucleus or outside the cells, depending on tyrosine-kinase signalling, thus interfering in cytoskeletal organization and cell differentiation, mostly in inflammatory and neoplastic processes. The aim was to investigate subcellular patterns of immunohistochemical expression of ANXA1 in neoplastic and non-neoplastic samples from patients with laryngeal squamous cell carcinomas (LSCC), to elucidate the role of ANXA1 in laryngeal carcinogenesis. Methods and results:, Serial analysis of gene expression experiments detected reduced expression of ANXA1 gene in LSCC compared with the corresponding non-neoplastic margins. Quantitative polymerase chain reaction confirmed ANXA1 low expression in 15 LSCC and eight matched normal samples. Thus, we investigated subcellular patterns of immunohistochemical expression of ANXA1 in 241 paraffin-embedded samples from 95 patients with LSCC. The results showed ANXA1 down-regulation in dysplastic, tumourous and metastatic lesions and provided evidence for the progressive migration of ANXA1 from the nucleus towards the membrane during laryngeal tumorigenesis. Conclusions:, ANXA1 dysregulation was observed early in laryngeal carcinogenesis, in intra-epithelial neoplasms; it was not found related to prognostic parameters, such as nodal metastases. [source] | |||||||||||||||||||||||||||||||||||||