Project description:We studied metabolic angiocrine mechanisms by which endothelial cell_ECs_ can contribute to muscle regeneration from ischemia by using endothelial specific pfkfb3 knockout mice_pfkfb3DEC_ after hind-limb ischemia_HLI_. During muscle regeneration, monocytes are recruited to the injured area and rapidly become macrophages which initially exhibit a more pro-inflammatory M1-like phenotype but soon thereafter functionally repolarize towards an M2-like phenotype to actively support muscle regeneration. Interestingly, macrophages derived from pfkfb3DEC failed to polarized to M2-like macrophages after HLI. Reduced macrophage polarization impairs angiogenesis and muscle regeneration. The RNAseq data are pfkfb3DEC and pfkfb3WT muscle derived macrophages 3 days after HLI.
Project description:Angiocrine signaling by liver sinusoidal endothelial cells (LSEC) regulates liver functions such as liver growth, metabolic maturation, and regeneration. Recently, we identified GATA4 as the master regulator of LSEC specification during development. Here, we studied endothelial GATA4 in the adult liver and in hepatic disease pathogenesis. We generated adult Clec4g-icretg/0xGata4fl/fl (Gata4LSEC KO) mice with deficiency of Gata4 in LSEC. Livers were analyzed by histology, electron microscopy, immunohistochemistry/immunofluorescence, in-situ hybridization, and by expression profiling and ATAC-sequencing of isolated LSEC. For liver regeneration, partial hepatectomy was performed. As models of liver fibrosis, CDAA diet and chronic CCl4 exposure were applied. Human single cell RNAseq data sets were analyzed for endothelial alterations in healthy and cirrhotic livers. Genetic Gata4 deficiency in LSEC in adult mice caused perisinusoidal liver fibrosis, hepatopathy and impaired liver regeneration. Sinusoidal capillarization and LSEC-to-continuous endothelial transdifferentiation were accompanied by a profibrotic angiocrine switch including de novo endothelial expression of hepatic stellate cell-activating cytokine PDGFB. Increased chromatin accessibility and amplification by activated Myc mediated angiocrine PDGFB expression. In CDAA diet-induced perisinusoidal liver fibrosis, LSEC showed repression of GATA4, activation of MYC and the profibrotic angiocrine switch already detected in Gata4LSEC KO mice. Comparison of CDAA-fed Gata4LSEC KO and control mice demonstrated that endothelial Gata4 indeed protects from dietary-induced perisinusoidal liver fibrosis. In human cirrhotic livers, Gata4-positive LSEC and endothelial Gata4 target genes were reduced, while non-LSEC endothelial cells and Myc target genes including PDGFB were enriched. Endothelial GATA4 protects from perisinusoidal liver fibrosis by repressing MYC activation and profibrotic angiocrine signaling on the chromatin level. Therapies targeting the GATA4/MYC/PDGFB/PDGFRβ axis offer a promising strategy for the prevention and treatment of liver fibrosis.
Project description:Angiocrine signaling by liver sinusoidal endothelial cells (LSEC) regulates liver functions such as liver growth, metabolic maturation, and regeneration. Recently, we identified GATA4 as the master regulator of LSEC specification during development. Here, we studied endothelial GATA4 in the adult liver and in hepatic disease pathogenesis. We generated adult Clec4g-icretg/0xGata4fl/fl (Gata4LSEC KO) mice with deficiency of Gata4 in LSEC. Livers were analyzed by histology, electron microscopy, immunohistochemistry/immunofluorescence, in-situ hybridization, and by expression profiling and ATAC-sequencing of isolated LSEC. For liver regeneration, partial hepatectomy was performed. As models of liver fibrosis, CDAA diet and chronic CCl4 exposure were applied. Human single cell RNAseq data sets were analyzed for endothelial alterations in healthy and cirrhotic livers. Genetic Gata4 deficiency in LSEC in adult mice caused perisinusoidal liver fibrosis, hepatopathy and impaired liver regeneration. Sinusoidal capillarization and LSEC-to-continuous endothelial transdifferentiation were accompanied by a profibrotic angiocrine switch including de novo endothelial expression of hepatic stellate cell-activating cytokine PDGFB. Increased chromatin accessibility and amplification by activated Myc mediated angiocrine PDGFB expression. In CDAA diet-induced perisinusoidal liver fibrosis, LSEC showed repression of GATA4, activation of MYC and the profibrotic angiocrine switch already detected in Gata4LSEC KO mice. Comparison of CDAA-fed Gata4LSEC KO and control mice demonstrated that endothelial Gata4 indeed protects from dietary-induced perisinusoidal liver fibrosis. In human cirrhotic livers, Gata4-positive LSEC and endothelial Gata4 target genes were reduced, while non-LSEC endothelial cells and Myc target genes including PDGFB were enriched. Endothelial GATA4 protects from perisinusoidal liver fibrosis by repressing MYC activation and profibrotic angiocrine signaling on the chromatin level. Therapies targeting the GATA4/MYC/PDGFB/PDGFRβ axis offer a promising strategy for the prevention and treatment of liver fibrosis.
Project description:Endothelial cells were transduced with different genes modulating signaling pathways and compared to GFP transduced control group to identify changes in the expression of the angiocrine factors. The experiment compared endothelial genetic changes upon Akt, MAP kinase and PymT activation.
Project description:Endothelial cells were transduced with different genes modulating signaling pathways and compared to GFP transduced control group to identify changes in the expression of the angiocrine factors.
Project description:Dysfunction of the vascular angiocrine system is critically involved in regenerative defects and fibrosis of injured organs. Previous studies have identified various angiocrine factors and found that risk factors such as aging and metabolic disorders can disturb the vascular angiocrine system in fibrotic organs. One existing key gap is what sense the fibrotic risk to modulate the vascular angiocrine system in organ fibrosis. Here, using human and mouse data, we discovered that the metabolic pathway hydrogen sulfide (H2S)-AMP-activated protein kinase (AMPK) is a sensor of fibrotic stress and serves as a key mechanism upregulating the angiocrine factor plasminogen activator inhibitor-1 (PAI-1) in endothelial cells to participate in lung fibrosis.
Project description:Microvascular endothelial cells (EC) display a high degree of phenotypic and functional heterogeneity among different organs. Organ-specific EC control their tissue microenvironment by angiocrine factors in health and disease. Liver sinusoidal EC (LSEC) are uniquely differentiated to fulfil important organ-specific functions in development, under homeostatic conditions, and in regeneration and liver pathology. Recently, Bmp2 has been identified by us as an organ-specific angiokine derived from LSEC. To study angiocrine Bmp2 signaling in the liver, we conditionally deleted Bmp2 in LSEC using EC subtype-specific Stab2-Cre mice. Genetic inactivation of hepatic angiocrine Bmp2 signaling in Stab2-Cre;Bmp2fl/fl (Bmp2LSECKO) mice caused massive iron overload in the liver, and increased serum iron levels and iron deposition in several organs similar to classic hereditary hemochromatosis. Iron overload was mediated by decreased hepatic expression of hepcidin, a key regulator of iron homeostasis. Thus, angiocrine Bmp2 signaling within the hepatic vascular niche represents a constitutive pathway indispensable for iron homeostasis in vivo that is non-redundant with Bmp6. Notably, we demonstrate that organ-specific angiocrine signaling is essential not only for the homeostasis of the respective organ, but also for the homeostasis of the whole organism.