Project description:Obesity is often associated with a low-grade systemic inflammation state that contributes to the development of insulin resistance and atherosclerotic complications. This is usually coupled with increased macrophage infiltration in the adipose tissue and a defect in adipocyte differentiation that results in accumulation of hypertrophic fat cells characterized by a deregulated pattern of adipokine expression. Here we show that knockdown of histone demethylase lsd1 in 3T3-L1 preadipocytes results in defective adipogenesis and derepression of an inflammatory program in these cells. The dataset consists of four sample groups: [1] 3T3-L1 preadipocytes (passage 19) transfected with a control scrambled siRNA at 24h after transfection (siC.24h), [2] 3T3-L1 preadipocytes (p.19) transfected with a siRNA directed against LSD1 at 24h after transfection (siLsd1.24h), [3] 3T3-L1 preadipocytes (p.21) transfected with a control scrambled siRNA at 48h after transfection (siC.48h), and [4] 3T3-L1 preadipocytes (p.21) transfected with a siRNA directed against LSD1 at 48h after transfection (siLsd1.48h). The 24h sample groups (siC.24h and siLsd1.24h) consist of two biological replicate samples; the 48h sample groups (siC.48h and siLsd1.48h) consist of three biological replicate samples. Each sample was hybridized to a separate array, for a total of ten arrays.
Project description:Biochemical crosstalk between two or more histone modifications is often observed in epigenetic enzyme regulation but its functional significance in cells has been difficult to discern. Prior enzymatic studies have revealed that Lys14 acetylation of histone H3 can inhibit Lys4 demethylation by lysine specific demethylase 1 (LSD1). Here we have engineered a mutant form of LSD1, Y391K, which renders the nucleosome demethylase activity of LSD1 insensitive to Lys14 acetylation. Y391K LSD1 knockin cells show increased repression of a set of genes associated with cellular adhesion. Chromatin profiling revealed that the cis-regulatory regions of these silenced genes display a higher level of H3 Lys14 acetylation than the baseline in unedited, parental cells. Y391K LSD1 knockin cells show diminished H3 mono-methyl Lys4 in the vicinity of these silenced genes, consistent with a role for enhanced LSD1 demethylase activity in these regions. These findings illuminate the functional consequences of disconnecting histone modification crosstalk for a key epigenetic enzyme in gene and chromatin regulation.
Project description:We mapped the genome-wide binding profiles of GR by using ChIP-Seq in livers from mice fed control or HFD diet after acute exogenous ligand (DEX) administration.
Project description:Analysis of differentiating LSD1-KD C2C12 myoblasts. We found LSD1 is an important regulator of oxidative phenotypes in skeletal muscle cells. Results provide insight into the molecular mechanisms underlying roles of LSD1 in myocytes.
Project description:Analysis of differentiating C2C12 myoblasts treated with two LSD1 specific inhibitors. We found LSD1 is an important regulator of oxidative phenotypes in skeletal muscle cells. Results provide insight into the molecular mechanisms underlying roles of LSD1 in myocytes.
Project description:Biochemical crosstalk between two or more histone modifications is often observed in epigenetic enzyme regulation but its functional significance in cells has been difficult to discern. Prior enzymatic studies have revealed that Lys14 acetylation of histone H3 can inhibit Lys4 demethylation by lysine specific demethylase 1 (LSD1). Here we have engineered a mutant form of LSD1, Y391K, which renders the nucleosome demethylase activity of LSD1 insensitive to Lys14 acetylation. Y391K LSD1 knockin cells show increased repression of a set of genes associated with cellular adhesion. Chromatin profiling revealed that the cis-regulatory regions of these silenced genes display a higher level of H3 Lys14 acetylation than the baseline in unedited, parental cells. Y391K LSD1 knockin cells show diminished H3 mono-methyl Lys4 in the vicinity of these silenced genes, consistent with a role for enhanced LSD1 demethylase activity in these regions. These findings illuminate the functional consequences of disconnecting histone modification crosstalk for a key epigenetic enzyme in gene and chromatin regulation.
Project description:KDM1A-mediated H3K4 demethylation is a well-established mechanism underlying transcriptional gene repression, but its role in gene activation is less clear. Here we report a critical function and novel mechanism of action of KDM1A in glucocorticoid receptor (GR)-mediated gene transcription. Biochemical purification of the nuclear GR complex revealed KDM1A as an integral component. In cell-free assays, GR modulates KDM1A-catalyzed H3K4 progressive demethylation by limiting loss of H3K4me1. Similarly, in cells KDM1A binds to most GR binding sites where it removes preprogrammed H3K4me2 but leaves H3K4me1 untouched. Blocking KDM1A catalytic activity prevents H3K4me2 removal, severely impairs GR binding to chromatin, and dysregulates GR-targeted genes. Taken together, these data suggest KDM1A-mediated H3K4me2 demethylation at GRBSs promotes GR binding and plays an important role in glucocorticoid-induced gene transcription, offering a new mechanism contributing to nuclear receptor mediated gene activation.