Endothelial GATA4 controls liver fibrosis and regeneration by preventing a pathogenic switch in angiocrine signaling [ATAC-seq]

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.肝窦内皮细胞（liver sinusoidal endothelial cells, LSEC）介导的血管内分泌信号可调控肝脏生长、代谢成熟与再生等核心肝脏功能。近期本团队鉴定出GATA4是发育过程中LSEC特化的核心调控因子。本研究针对成年肝脏及肝脏疾病发病机制中的内皮细胞GATA4展开探究。 我们构建了LSEC中Gata4缺陷的成年Clec4g-icretg/0xGata4fl/fl（Gata4LSEC KO）小鼠模型。通过组织学检测、电子显微镜成像、免疫组织化学/免疫荧光染色、原位杂交技术，以及分离LSEC的表达谱分析与ATAC测序（ATAC-sequencing），对小鼠肝脏开展系统性表征。针对肝脏再生模型，我们实施了部分肝切除术；采用CDAA饲料喂养与慢性四氯化碳（CCl4）暴露两种方式构建肝纤维化模型。同时分析人类单细胞RNA测序数据集，以探究健康肝脏与肝硬化肝脏中内皮细胞的异常改变。 成年小鼠LSEC中Gata4基因缺陷可诱发窦周肝纤维化、肝病，并损害肝脏再生能力。窦毛细血管化及LSEC向连续性内皮细胞转分化过程中，伴随促纤维化血管内分泌表型转换，包括肝星状细胞活化细胞因子PDGFB的内皮细胞新生表达。染色质可及性增加与活化的Myc介导的血管内分泌PDGFB表达扩增进一步加剧了该病理进程。在CDAA饲料诱导的窦周肝纤维化模型中，Gata4LSEC KO小鼠中已观察到LSEC的GATA4表达抑制、MYC活化及促纤维化血管内分泌表型转换。对比CDAA喂养的Gata4LSEC KO小鼠与对照小鼠，结果证实内皮Gata4确实可抵御饮食诱导的窦周肝纤维化。在人类肝硬化肝脏中，GATA4阳性LSEC及内皮GATA4靶基因的表达水平显著降低，而非LSEC内皮细胞与包括PDGFB在内的MYC靶基因则呈现富集表达。 内皮细胞GATA4通过在染色质层面抑制MYC活化与促纤维化血管内分泌信号通路，从而发挥抵御窦周肝纤维化的作用。靶向GATA4/MYC/PDGFB/PDGFRβ轴的治疗策略，为肝纤维化的预防与临床治疗提供了极具前景的全新方向。

搜集汇总

背景与挑战

背景概述

该数据集通过ATAC-seq技术，研究小鼠肝窦内皮细胞中GATA4转录因子在肝纤维化和再生过程中的作用。数据集包含6个样本（3个GATA4敲除和3个对照），分析显示GATA4通过调控染色质可及性抑制MYC激活和促纤维化血管分泌信号，从而防止肝纤维化，为相关治疗策略提供依据。