Project description:Lipolysis is an early event during derma; fibrosis progression. We wanted to see how the loss of lipolysis impacted cell dynamics within the
Project description:Adipocyte lipolysis controls systemic energy levels and metabolic homeostasis. Lipolysis is regulated by post-translational modifications of key lipolytic enzymes. However, less is known about the transcriptional mechanisms that regulate lipolysis. Here, we identify the transcriptional factor interferon regulatory factor-2 binding protein 2 (IRF2BP2) as a repressor of adipocyte lipolysis. Deletion of IRF2BP2 in primary human adipocytes increases lipolysis without affecting glucose uptake, whereas IRF2BP2 overexpression decreases lipolysis. RNA-seq and ChIP-seq analyses reveal that IRF2BP2 directly represses several lipolysis-related genes, including LIPE (HSL, hormone sensitive lipase), which encodes the rate-limiting enzyme in lipolysis. Adipocyte-selective deletion of Irf2bp2 in mice increases Lipe expression and free fatty acid levels, resulting in elevated adipose tissue inflammation and glucose intolerance. Altogether, these findings demonstrate that IRF2BP2 restrains adipocyte lipolysis and opens new avenues to target lipolysis for the treatment of metabolic disease.
Project description:Adipocyte lipolysis controls systemic energy levels and metabolic homeostasis. Lipolysis is regulated by post-translational modifications of key lipolytic enzymes. However, less is known about the transcriptional mechanisms that regulate lipolysis. Here, we identify the transcriptional factor interferon regulatory factor-2 binding protein 2 (IRF2BP2) as a repressor of adipocyte lipolysis. Deletion of IRF2BP2 in primary human adipocytes increases lipolysis without affecting glucose uptake, whereas IRF2BP2 overexpression decreases lipolysis. RNA-seq and ChIP-seq analyses reveal that IRF2BP2 directly represses several lipolysis-related genes, including LIPE (HSL, hormone sensitive lipase), which encodes the rate-limiting enzyme in lipolysis. Adipocyte-selective deletion of Irf2bp2 in mice increases Lipe expression and free fatty acid levels, resulting in elevated adipose tissue inflammation and glucose intolerance. Altogether, these findings demonstrate that IRF2BP2 restrains adipocyte lipolysis and opens new avenues to target lipolysis for the treatment of metabolic disease.
Project description:Adipocyte lipolysis controls systemic energy levels and metabolic homeostasis. Lipolysis is regulated by post-translational modifications of key lipolytic enzymes. However, less is known about the transcriptional mechanisms that regulate lipolysis. Here, we identify the transcriptional factor interferon regulatory factor-2 binding protein 2 (IRF2BP2) as a repressor of adipocyte lipolysis. Deletion of IRF2BP2 in primary human adipocytes increases lipolysis without affecting glucose uptake, whereas IRF2BP2 overexpression decreases lipolysis. RNA-seq and ChIP-seq analyses reveal that IRF2BP2 directly represses several lipolysis-related genes, including LIPE (HSL, hormone sensitive lipase), which encodes the rate-limiting enzyme in lipolysis. Adipocyte-selective deletion of Irf2bp2 in mice increases Lipe expression and free fatty acid levels, resulting in elevated adipose tissue inflammation and glucose intolerance. Altogether, these findings demonstrate that IRF2BP2 restrains adipocyte lipolysis and opens new avenues to target lipolysis for the treatment of metabolic disease.
Project description:Objectives: Eph/Ephrin cell-cell signaling is emerging as a key player in tissue fibrogenesis. The aim of this study was to test the hypothesis that the receptor tyrosine kinase EphB2 mediates dermal fibrosis in systemic sclerosis (SSc). Methods: We assessed normal and SSc human skin biopsies for EphB2 expression. The in vivo role of EphB2 in skin fibrosis was investigated by subjecting EphB2-knockout mice to both bleomycin-induced and tight skin (Tsk1/+) genetic mouse models. EphB2 kinase-dead and overactive point mutant mice were used to evaluate the role of EphB2 forward signaling in bleomycin-induced dermal fibrosis. In vitro studies were performed on dermal fibroblasts from SSc patients and healthy controls, which was followed by in vivo analysis of fibroblast-specific EphB2 deficient mice. Results: Expression of EphB2 is upregulated in SSc skin tissue and explanted SSc dermal fibroblasts compared to healthy controls. EphB2 expression is elevated in two animal models of dermal fibrosis. In mice, EphB2 drives dermal fibrosis in both the bleomycin and the Tsk1/+ models of skin fibrosis. EphB2 forward signaling is a critical mediator of dermal fibrosis. Transforming growth factor-β (TGFβ) cytokines upregulate EphB2 in dermal fibroblasts via non-canonical TGFβ/SMAD signaling and silencing EphB2 in dermal fibroblasts is sufficient to dampen TGFβ-induced fibroblast-to-myofibroblast differentiation. Moreover, mice with fibroblast-specific deletion of EphB2 showed impaired fibroblast-to-myofibroblast differentiation and reduced skin fibrosis upon bleomycin challenge. Conclusion: Our data implicate EphB2 overexpression and kinase-mediated forward signaling in the development of dermal fibrosis in SSc. EphB2 thus represents a potential new therapeutic target for SSc.
Project description:Adaptation to acidosis has been reported to induce a shift towards fatty acid metabolism. We observed that conditioned medium of HCT, FaDu and SiHa adapted to acidosis (pH6.5) induced higher lipolysis of primary subcutaneous and mesenteric adipocytes compared to cancer cells maintained at pH7.4. In order to identify the prolipolytic factors induced by acidosis, we examined the differences between cancer cells adapted to pH6.5 and those maintained at pH7.4 by RNA sequencing. Cancer cells adapted to pH6.5 showed profound alterations in their gene expression compared with cancer cells maintained at pH7.4. Here, we focused on predicted secreted genes. We determined that 84 altered genes predicted to be secreted proteins overlapped between the 3 cancer cell lines, 24 of which were overexpressed. The role of these overexpressed genes was determined in vitro. We studied their role in inducing adipocyte lipolysis and in the depletion of adipose tissue observed in cancer cachexia.
Project description:To investigate the effect of ZNF395 on adipogenesis, we tested whether ZNF395 enhance cell conversion from human dermal Fibroblast (FIB) to Adipocyte (ADP). PPARG2 was reported as a master regulator and can induce adipogenesis in non-adipogenic fibroblasts. We transduced PPARG2 with or without ZNF395 in FIB with lentivirus. Interestingly, co-transduction of PPARG2 and ZNF395 showed higher occurrence of adipocyte-like cells as compared with PPARG2 alone. Moreover, genes related with lipid metabolic process and lipid transport was significantly up-regulated in combination of PPARG2 and ZNF395. These results suggest that ZNF395 co-ordinate the transcriptional regulatory pathway with PPARG2, necessary for the induction of adipogenesis. Total RNA was obteined from human dermal fibroblast transduced with mock lentivirus vector (FIB_ctrl), PPARG2 (FIB_PPARG2) and co-transduced with PPARG2 and ZNF395 (FIB_PPARG2+ZNF395).