Project description:The adipocyte-derived hormone leptin maintains energy balance by acting on hypothalamic leptin receptors (Leprs) that trigger the signal transducer and activator of transcription 3 (Stat3). Although disruption of Lepr-Stat3 signaling promotes obesity in mice, other features of Lepr function, such as fertility, seem normal, pointing to the involvement of additional regulators. Here we show that the cyclic AMP responsive elementâ??binding protein-1 (Creb1)-regulated transcription coactivator-1 (Crtc1) is required for energy balance and reproductionâ??Crtc1-/- mice are hyperphagic, obese and infertile. Hypothalamic Crtc1 was phosphorylated and inactive in leptin-deficient ob/ob mice; leptin administration increased amounts of dephosphorylated nuclear Crtc1. Dephosphorylated Crtc1 stimulated expression of the Cartpt and Kiss1 genes, which encode hypothalamic neuropeptides that mediate leptinâ??s effects on satiety and fertility. Crtc1 overexpression in hypothalamic cells increased Cartpt and Kiss1 gene expression, whereas Crtc1 depletion decreased it. Indeed, leptin enhanced Crtc1 activity over the Cartpt and Kiss1 promoters in cells overexpressing Lepr and these effects were disrupted by expression of a dominant-negative Creb1 polypeptide. As leptin administration increased recruitment of hypothalamic Crtc1 to Cartpt and Kiss1 promoters, our results indicate that the Creb1-Crtc1 pathway mediates the central effects of hormones and nutrients on energy balance and fertility. Experiment Overall Design: Mice were fasted overnight for 18h and refed for 6h. Hypothalami were obtained from 3 wild-type and 3 Crtc1 knockout mice. Total RNA was isolated from each sample and equal amounts from each sample were pooled for the microarray.
Project description:The adipocyte-derived hormone leptin maintains energy balance by acting on hypothalamic leptin receptors (Leprs) that trigger the signal transducer and activator of transcription 3 (Stat3). Although disruption of Lepr-Stat3 signaling promotes obesity in mice, other features of Lepr function, such as fertility, seem normal, pointing to the involvement of additional regulators. Here we show that the cyclic AMP responsive element–binding protein-1 (Creb1)-regulated transcription coactivator-1 (Crtc1) is required for energy balance and reproduction—Crtc1-/- mice are hyperphagic, obese and infertile. Hypothalamic Crtc1 was phosphorylated and inactive in leptin-deficient ob/ob mice; leptin administration increased amounts of dephosphorylated nuclear Crtc1. Dephosphorylated Crtc1 stimulated expression of the Cartpt and Kiss1 genes, which encode hypothalamic neuropeptides that mediate leptin’s effects on satiety and fertility. Crtc1 overexpression in hypothalamic cells increased Cartpt and Kiss1 gene expression, whereas Crtc1 depletion decreased it. Indeed, leptin enhanced Crtc1 activity over the Cartpt and Kiss1 promoters in cells overexpressing Lepr and these effects were disrupted by expression of a dominant-negative Creb1 polypeptide. As leptin administration increased recruitment of hypothalamic Crtc1 to Cartpt and Kiss1 promoters, our results indicate that the Creb1-Crtc1 pathway mediates the central effects of hormones and nutrients on energy balance and fertility.
Project description:Background: Gene expression regulated by the transcription factor cAMP-response element binding protein (CREB) is modulated by transcriptional coactivators such as CBP/P300 and CREB-regulated transcription coactivator-1 (CRTC1). However, the genome-wide occupancy profile of CRTC1 in neurons is unknown. Aim: We analyzed the genome-wide occupancy profiles of CRTC1 in primary cortical neurons in basal and stimulated conditions after treatment with forskolin and potassium chloride (FK), which induces CRTC1 dephosphorylation, nuclear translocation and binding to promoter regions of target genes (PMID: 29269871). Methods: 40 million reads per sample were quality-filtered and aligned to the reference genome (mm10) before input normalization, peak calling and annotation. Results: We identified strong induction of CRTC1 occupancy after treatment with FK at over 2,500 binding sites comprising proximal promoter regions and distal regions, including well-characterized neuronal activity-regulated enhancers (PMID: 20393465). Conclusions: Neuronal activity induces binding of CRTC1 to promoter and enhancer regions of target genes.
