Project description:Transforming growth factor-β (TGF-β) signalling controls a number of cerebral functions and dysfunctions including synaptogenesis, amyloid-β accumulation, apoptosis and excitotoxicity. Using cultured cortical neurons prepared from either wild type or transgenic mice over-expressing a TGF-β responsive luciferase reporter gene (SBE-Luc), we demonstrated a progressive loss of TGF-β signalling during neuronal maturation and survival. Moreover, we showed that neurons exhibit increasing amounts of the serine protease HtrA1 (high temperature responsive antigen 1) and corresponding cleavage products during both in vitro neuronal maturation and brain development. In parallel of its ability to promote degradation of TGF-β1, we demonstrated that blockage of the proteolytic activity of HtrA1 leads to a restoration of TGF-β signalling, subsequent overexpression of the serpin type -1 plasminogen activator inhibitor (PAI-1) and neuronal death. Altogether, we propose that the balance between HtrA1 and TGF-β could be one of the critical events controlling both neuronal maturation and developmental survival. Keywords: HtrA1 / neuronal survival / PAI-1 / TGF-β signalling / tPA
Project description:Transforming growth factor-M-NM-2 (TGF-M-NM-2) signalling controls a number of cerebral functions and dysfunctions including synaptogenesis, amyloid-M-NM-2 accumulation, apoptosis and excitotoxicity. Using cultured cortical neurons prepared from either wild type or transgenic mice over-expressing a TGF-M-NM-2 responsive luciferase reporter gene (SBE-Luc), we demonstrated a progressive loss of TGF-M-NM-2 signalling during neuronal maturation and survival. Moreover, we showed that neurons exhibit increasing amounts of the serine protease HtrA1 (high temperature responsive antigen 1) and corresponding cleavage products during both in vitro neuronal maturation and brain development. In parallel of its ability to promote degradation of TGF-M-NM-21, we demonstrated that blockage of the proteolytic activity of HtrA1 leads to a restoration of TGF-M-NM-2 signalling, subsequent overexpression of the serpin type -1 plasminogen activator inhibitor (PAI-1) and neuronal death. Altogether, we propose that the balance between HtrA1 and TGF-M-NM-2 could be one of the critical events controlling both neuronal maturation and developmental survival. Keywords: HtrA1 / neuronal survival / PAI-1 / TGF-M-NM-2 signalling / tPA Total RNA were extracted from 3 cultures of 2 DIV Human neurons. For each stage, equal amounts of each RNA were pooled and 5M-BM-5g were reverse-transcribed, labelled and hybridized on pangenomic microarrays. Each pool was hybridized in duplicate dye-swap independent experiments.
Project description:Alb/TGF-ß1 (TGF-ß) transgenic mice on mixed (CBAxB6) genetic background are characterized by renal fibrosis with mild or severe phenotype. Our aim was to examine the influence of genetic background on TGF-ß induced renal fibrosis in transgenic mice, and to elucidate the molecular details of strain dependent progression of fibrosis. We generated congenic B6-TGFß transgenic mice and CBAxB6-TGFß transgenic hybrid mice. Survival, proteinuria, renal histology, renal transcriptome using cDNA microarray and protein expression were analysed.
Project description:The current study examines the functional role of VEPH1, a PH domain containing protein and the human ortholog of Drosophila melted, in ovarian cancer cell lines. Elevated VEPH1 is associated with FOXO and Hippo signaling and was found to suppress TGF-ß induced target genes. SKOV3 cell lines were established as either CdCl2 inducible Flag-tagged VEPH1 expression or mock-transfected. Gene expression profiles were then generated both with and without the presence of TGF-ß to induce TGF-ß signaling. 3 replicates per treatment group were used.
Project description:Glucose homeostasis is dependent on functional pancreatic α and ß cells. Mechanisms underlying generation and maturation of these endocrine cells remain unclear. Here, we unravel the molecular mode of action of ISL1 in controlling α cell fate and endocrine differentiation in the pancreas. By combining transgenic mouse models, transcriptomic and epigenomic profiling, we uncover that elimination of Isl1 results in a diabetic phenotype with a complete loss of α cells, disrupted pancreatic islet architecture, downregulation of maturation markers of ß cells, and an enrichment in an intermediate endocrine progenitor transcriptomic profile. Mechanistically, apart from the altered transcriptome of pancreatic endocrine cells, Isl1 elimination results in altered silencing H3K27me3 histone modifications in the promoter regions of the essential genes for endocrine cell differentiation. Our results thus show that ISL1 transcriptionally and epigenetically controls α cell fate competence, and ß cell maturation, suggesting that ISL1 is a critical component for generating functional α and ß cells.
Project description:Glucose homeostasis is dependent on functional pancreatic α and ß cells. Mechanisms underlying generation and maturation of these endocrine cells remain unclear. Here, we unravel the molecular mode of action of ISL1 in controlling α cell fate and endocrine differentiation in the pancreas. By combining transgenic mouse models, transcriptomic and epigenomic profiling, we uncover that elimination of Isl1 results in a diabetic phenotype with a complete loss of α cells, disrupted pancreatic islet architecture, downregulation of maturation markers of ß cells, and an enrichment in an intermediate endocrine progenitor transcriptomic profile. Mechanistically, apart from the altered transcriptome of pancreatic endocrine cells, Isl1 elimination results in altered silencing H3K27me3 histone modifications in the promoter regions of the essential genes for endocrine cell differentiation. Our results thus show that ISL1 transcriptionally and epigenetically controls α cell fate competence, and ß cell maturation, suggesting that ISL1 is a critical component for generating functional α and ß cells.
Project description:iNKT cells are a T lymphocyte subset displaying an innate effector phenotype that is acquired through a thymic developmental program controlled by microRNAs (miRNAs). iNKT cells lacking all miRNAs by the deletion of Dicer (Dicer KO) are markedly reduced and display a complete maturation block. In this study, we sought to gain insight into the miRNA-regulated genetic program required for iNKT cell development. By systemic analysis, we identified transcripts differentially expressed between thymic WT or Dicer KO iNKT cells and targeted by the iNKT cell-specific miRNAs. TGF-βRII, a molecule critically implicated in iNKT cell maturation, was found upregulated in Dicer KO iNKT cells together with increased TGF-β-dependent signaling. miRNAs belonging to the paralog miR-106a~363, miR-106b~25 and miR-17~92 clusters were predicted to target TGF-βRII mRNA during iNKT cell development. Thymic iNKT cells lacking all three miRNA clusters displayed both increased TGF-βRII expression and signaling and a maturation block, recapitulating those found in Dicer KO iNKT cells. Consistently, inhibition of TGF-β-dependent signaling in the absence of miRNAs, by crossing TGF-βRII KO and Dicer KO mice, rescued iNKT cell maturation. Collectively, our results highlight a fundamental requirement of the modulation of TGF-β-dependent signaling by miRNAs for iNKT cell development
Project description:Very little is known about how intervertebral disc (IVD) is formed or maintained. Members of the TGF-ß superfamily are secreted signaling proteins that regulate many aspects of development including cellular differentiation. We recently showed that deletion of Tgfbr2 in Col2a expressing tissue results in alterations in development of IVD annulus fibrosus. The results suggested TGF-ß has an important role in regulating development of the axial skeleton, however, the mechanistic basis of TGF-ß action in these specialized joints is not known. To understand the mechanism of TGF-ß action in IVD development, we undertook a global analysis of gene expression comparing gene expression profiles in sclerotome cultures treated with TGF-ß or BMP4. As expected, treatment with BMP4 resulted in up-regulation of cartilage marker genes including Acan, Sox 5, Sox6, and Sox9. In contrast, treatment with TGF-ß1 did not regulate expression of cartilage markers but instead resulted in up-regulation of many IVD markers including Fmod and Adamtsl2. We propose TGF-ß has two functions in IVD development: 1) to prevent chondrocyte differentiation in the presumptive IVD and 2) to promote differentiation of annulus fibrosus from sclerotome. We have identified genes that are enriched in the IVD and regulated by TGF-ß that warrant further investigation as regulators of IVD development.
Project description:Transcriptional analysis of identified DRG subpopulations. Cell-type specific intrinsic programs instruct neuronal subpopulations before target-derived factors influence later neuronal maturation. Retrograde neurotrophin signaling controls neuronal survival and maturation of dorsal root ganglion (DRG) sensory neurons, but how these potent signaling pathways intersect with transcriptional programs established at earlier developmental stages remains poorly understood. Here we determine the consequences of genetic alternation of NT3 signaling on genome-wide transcription programs in proprioceptors, an important sensory neuron subpopulation involved in motor reflex behavior. We find that the expression of many proprioceptor-enriched genes is dramatically altered by genetic NT3 elimination, independent of survival-related activities. Combinatorial analysis of gene expression profiles with proprioceptors isolated from mice expressing surplus muscular NT3 identifies an anticorrelated gene set with transcriptional levels scaled in opposite directions. Voluntary running experiments in adult mice further demonstrate the maintenance of transcriptional adjustability of genes expressed by DRG neurons, pointing to life-long gene expression plasticity in sensory neurons.
Project description:Very little is known about how intervertebral disc (IVD) is formed or maintained. Members of the TGF-ß superfamily are secreted signaling proteins that regulate many aspects of development including cellular differentiation. We recently showed that deletion of Tgfbr2 in Col2a expressing tissue results in alterations in development of IVD annulus fibrosus. The results suggested TGF-ß has an important role in regulating development of the axial skeleton, however, the mechanistic basis of TGF-ß action in these specialized joints is not known. One of the hurdles to understanding development of IVD is a lack of known markers. To identify genes that are enriched in the developing IVD and to begin to understand the mechanism of TGF-ß action in IVD development, we undertook a global analysis of gene expression comparing gene expression profiles in developing vertebrae and IVD. We also compared expression profiles in tissues from wild type and Tgfbr2 mutant mice. Lists of IVD and vertebrae enriched genes were generated. Expression patterns for several genes were verified either through in situ hybridization or literature/ database searches resulting in a list of genes that can be used as markers of IVD. Cluster analysis using genes listed under the Gene Ontology terms multicellular organism development and pattern specification indicated that mutant IVD more closely resembled vertebrae than wild type IVD. We propose TGF-ß has two functions in IVD development: 1) to prevent chondrocyte differentiation in the presumptive IVD and 2) to promote differentiation of annulus fibrosus from sclerotome. We have identified genes that are enriched in the IVD and regulated by TGF-ß that warrant further investigation as regulators of IVD development. Thirteen samples were analyzed. This includes three biological replicates of laser captured IVD from E13.5 day control mice, three biological replicates of laser captured vertebrae from the same E13.5 day control mice, three biological relicates of laser captured vertebrae from E13.5 day Col2aCre;Tgfbr2lox/lox mice, and four biological replicates of laser captured IVD from E13.5 day Col2aCre;Tgfbr2lox/lox mice.