Fast-spiking (FS) interneurons are important elements of neocortical circuitry that constitute the primary source of synaptic inhibition in adult cortex and impart temporal organization on ongoing cortical activity. The highly specialized intrinsic membrane and firing properties that allow cortical FS interneurons to perform these functions are attributable to equally specialized gene expression, which is ultimately coordinated by cell-type-specific transcriptional regulation. Although embryonic transcriptional events govern the initial steps of cell-type specification in most cortical interneurons, including FS cells, the electrophysiological properties that distinguish adult cortical cell types emerge relatively late in postnatal development, and the transcriptional events that drive this maturational process are not known. To address this, we used mouse whole-genome microarrays and whole-cell patch clamp to characterize the transcriptional and electrophysiological maturation of cortical FS interneurons between postnatal day 7 (P7) and P40. We found that the intrinsic and synaptic physiology of FS cells undergoes profound regulation over the first 4 postnatal weeks and that these changes are correlated with primarily monotonic but bidirectional transcriptional regulation of thousands of genes belonging to multiple functional classes. Using our microarray screen as a guide, we discovered that upregulation of two-pore K leak channels between P10 and P25 contributes to one of the major differences between the intrinsic membrane properties of immature and adult FS cells and found a number of other candidate genes that likely confer cell-type specificity on mature FS cells.
Transcriptional and electrophysiological maturation of neocortical fast-spiking GABAergic interneurons.
Specimen part
View SamplesLevels of C/EBP are low in myeloid blast crisis (BC) of chronic myelogenous leukemia (CML) and its expression in p210BCR/ABL-expressing hematopoietic cells induces granulocytic differentiation, inhibits proliferation and suppresses leukemogenesis. To assess the mechanisms involved in these effects, C/EBP targets were identified by microarray analyses. Upon C/EBP activation, expression of c-Myb and GATA-2 was repressed in 32D-BCR/ABL, K562 and CML-BC primary cells but only c-Myb levels decreased slightly in CD34+ normal progenitors. The role of these two genes for the biological effects of C/EBP was assessed by perturbing their expression in K562 cells. Expression of c-Myb blocked the proliferation inhibition and differentiation-inducing effects of C/EBP while c-Myb siRNA treatment enhanced C/EBP-mediated proliferation inhibition and induced changes in gene expression indicative of monocytic differentiation. GATA-2 expression suppressed the proliferation inhibitory effect of C/EBP but blocked in part the effect on differentiation; GATA-2 siRNA treatment had no effects on C/EBP induction of differentiation but inhibited proliferation of K562 cells, alone or upon C/EBP activation. In summary, the effects of C/EBP in p210BCR/ABL -expressing cells depend, in part, on transcriptional repression of c-Myb and GATA-2. Since perturbation of c-Myb and GATA-2 expression has non identical consequences for proliferation and differentiation of K562 cells, the effects of C/EBP appear to involve different transcription-regulated targets.
Transcriptional repression of c-Myb and GATA-2 is involved in the biologic effects of C/EBPalpha in p210BCR/ABL-expressing cells.
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View SamplesStreptococcus pyogenes is a major causative agent of tonsillitis or pharyngitis in children, which can lead to more invasive infections and noninfectious sequellae. S. pyogenes can persist in tonsils, while one-third of children treated with antibiotics continue to shed streptococci and have recurrent infections. Mouse nasal-associated lymphoid tissue (NALT) is functionally analogous to human oropharangeal lymphoid tissues. The innate immune responses of nave cells from a mucosal site to S. pyogenes is not well described; therefore, we infected C57BL/6 mice intranasally with 108 CFU S. pyogenes. Transcriptional responses by NALT after S. pyogenes infection were analyzed by Affymetrix microarray and quantitative RT-PCR. Wild-type S. pyogenes induces transcription of both type I and IFN-gamma-responsive genes, pro-inflammatory genes, and acute phase response plasma proteins within 24h after infection. Invasion of NALT and the induction of the interferon response were not dependent on expression of anti-phagocytic M1 protein. However, infection with an attenuated, less invasive mutant indicated that a robust innate response by NALT is significantly influenced by intra-NALT bacterial load. Granulocytic populations of NALT, cervical lymph nodes and spleen were discriminated by characteristic surface and intracellular markers. Intranasal infection induces systemic release of neutrophils and a substantial influx of neutrophils into NALT at 24h, which decline by 48h after infection. Macrophages do not significantly increase in S. pyogenes-infected NALT. Intranasal infection of IFN-gamma -/- (GKO) C57BL/6 mice did not lead to systemic dissemination of wild type S. pyogenes, despite reduced expression of IFN-gamma-responsive mRNAs in NALT. Infected GKO mice had an unregulated influx of neutrophils into NALT compared to immunocompetant mice and mice treated with an anti-IFN-gamma antibody more rapidly cleared S. pyogenes from NALT. Thus, IFN-gamma-induced responses have a suppressive influence on early clearance of this pathogen from NALT.
No associated publication
Specimen part
View SamplesNOD mice are an inbred strain that display enhanced MZ B cell differentiation from an early age. Interestingly, several lines of evidence implicate MZ B cells in this strain as important contributors to the T cell mediated beta cell destruction associated with the development of type 1 diabetes (T1D). In order to develop a better understanding of the underlying causes for augmented MZ B cell production in NOD mice, we obtained the transcriptional profiles of FO and MZ subsets and TR precursors from NOD mice and compared them to those of the B6 strain.
Intrinsic molecular factors cause aberrant expansion of the splenic marginal zone B cell population in nonobese diabetic mice.
Sex, Age, Specimen part
View SamplesCellular stress responses can be activated following functional defects in organelles such as mitochondria and the endoplasmic reticulum. Mitochondrial dysfunction caused by loss of the serine protease HtrA2 leads to a progressive movement disorder in mice and has been linked to parkinsonian neurodegeneration in humans. Here we demonstrate that loss of HtrA2 results in transcriptional up-regulation of nuclear genes characteristic of the integrated stress response, including the transcription factor CHOP, selectively in the brain. We also show that loss of HtrA2 results in the accumulation of unfolded proteins in the mitochondria, defective mitochondrial respiration and enhanced production of reactive oxygen species that contribute to the induction of CHOP expression and to neuronal cell death. CHOP expression is also significantly increased in Parkinsons disease patients brain tissue. We therefore propose that this brain-specific transcriptional response to stress may be important in the advance of neurodegenerative diseases.
No associated publication
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View SamplesWinged bean (WB), Psophocarpus tetragonolobus, is a tropical legume, the potential of which is not yet been understood. We found that a 5 week-oral administration of WB seed extract inhibited wrinkle formation induced by repeated tape stripping (TS), which is a model of lichenification in human chronic eczematous dermatitis.
Effect of oral intake of winged bean extract on a skin lichenification model: evaluation by microarray analysis.
Sex, Age, Specimen part, Treatment
View SamplesFumarate hydratase (FH) mutations cause hereditary leiomyomatosis and renal cell cancer (HLRCC). We have conditionally inactivated the murine ortholog (Fh1) in renal tubular epithelial cells in order to generate an in vivo model of HLRCC. Fh1 knockout mice recapitulates important aspects of HLRCC including the development of renal cysts that overexpress hypoxia inducible factor alpha (Hifa) and Hif-target genes.
No associated publication
No sample metadata fields
View SamplesEndothelin-1 (ET-1) plays a critical role in connective tissue remodeling by fibroblasts during tissue repair and fibrosis. We investigated the molecular pathways in the transmission of ET-1 signals that lead to features of connective tissue remodeling, in particular the role of FAK (focal adhesion kinase).
Inhibition of focal adhesion kinase prevents experimental lung fibrosis and myofibroblast formation.
Specimen part, Treatment
View SamplesQuercetin is a food component that may ameliorate the diabetic symptoms. We examined hepatic gene expression of BALB/c mice with streptozotocin (STZ)-induced diabetes to elucidate the mechanism of the protective effect of dietary quercetin on diabetes-associated liver injury.
Dietary quercetin alleviates diabetic symptoms and reduces streptozotocin-induced disturbance of hepatic gene expression in mice.
Sex, Specimen part
View SamplesTo determine the effect of consumption of a quercetin-rich diet on obesity and dysregulated hepatic gene expression, C56BL/6J mice were fed for 20 weeks on control or a Western diet high in fat, cholesterol and sucrose, both with or without 0.05% quercetin. Chronic dietary intake of quercetin reduced body weight gain and visceral and liver fat accumulation, and improved hyperglyceamia, hyperinsulinaemia, dyslipidaemia in mice fed a Western-style diet.
Chronic dietary intake of quercetin alleviates hepatic fat accumulation associated with consumption of a Western-style diet in C57/BL6J mice.
Sex, Specimen part
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