Estrogen-independent Epigenetic Mechanisms Regulate Gender Dimorphisms in Cardiac Reparative Functions of Bone Marrow Progenitor Cells [RNA-Seq]. Estrogen-independent Epigenetic Mechanisms Regulate Gender Dimorphisms in Cardiac Reparative Functions of Bone Marrow Progenitor Cells [RNA-Seq]

Historically, lower incidence of CVD and related deaths in women compared to men of the same age has been attributed to female sex hormones, particularly estrogen and its receptors. Autologous Bone marrow stem cell (BMSC) clinical trials for cardiac cell therapy overwhelmingly included male patients; however, meta-analysis data on these trials suggest a better functional outcome in women compared to men. Direct comparison of gender-specific cardiac reparative activity and estrogen-independent mechanisms that regulate gender-specific dimorphisms of BMSC has not been studied. This study was designed to identify sex hormone-independent mechanisms that regulate superior reparative properties of female endothelial progenitor cells (EPCs) post-MI, particularly epigenetic mechanisms. Male (M), female (F), and ovariectomized female (OVX) mice-derived EPCs were subjected to a series of molecular and epigenetic analyses followed by in vivo functional assessments of cardiac repair. RNA sequencing and other quantitative assays showed a similar genetic profile between F-EPCs and OVX-EPCs, distinct from M-EPCs that displayed significant up-regulation of inflammation-related genes. F-EPCs and OVX EPCs secrete higher levels of proangiogenic factors, lower levels of proinflammatory cytokines and show better cardiac reparative activity after intra-cardiac injections in a male mouse model of myocardial infarction (MI). Epigenetic sequencing revealed a marked difference in the occupancy of the gene repressive H3K9me3 mark, particularly at transcription start sites of key angiogenic and proinflammatory genes in male EPCs compared to female and ovariectomized EPCs. Our study unveiled that functional gender dimorphism in EPCs is, in part, mediated by differential epigenetic regulation of the proinflammatory and anti-angiogenic gene CCL3, orchestrated by the control of H3K9me3 by histone methyltransferase, G9a/Ehmt2. Our research highlights the importance of considering gender of donor cells for progenitor based tissue repair. Overall design: To investigate estrogen-independent epigenetic mechanisms which regulate cardiac reparative properties of genderr dimorphic properties of endothelial progenitor cells

长期以来，同年龄段人群中女性心血管疾病（Cardiovascular Disease, CVD）及其相关死亡的发生率低于男性，这一现象曾被归因于女性性激素，尤其是雌激素及其受体。针对心脏细胞治疗的自体骨髓干细胞（Bone Marrow Stem Cell, BMSC）临床试验中，入组患者绝大多数为男性；但针对这些试验的荟萃分析数据显示，女性患者的功能转归优于男性。目前尚未有研究直接比较性别特异性心脏修复活性，以及调控骨髓干细胞性别二态性的雌激素非依赖机制。本研究旨在阐明调控心肌梗死（Myocardial Infarction, MI）后女性内皮祖细胞（Endothelial Progenitor Cells, EPCs）优异修复特性的性激素非依赖机制，尤其是表观遗传调控机制。研究人员对来自雄性（M）、雌性（F）以及去卵巢雌性（Ovariectomized, OVX）小鼠的内皮祖细胞开展了一系列分子与表观遗传分析，随后对其心脏修复能力进行了体内功能评估。RNA测序与其他定量检测结果显示，雌性内皮祖细胞（F-EPCs）与去卵巢雌性内皮祖细胞（OVX-EPCs）的遗传谱相似，而雄性内皮祖细胞（M-EPCs）的遗传谱与之显著不同，后者的炎症相关基因呈现明显上调。在雄性小鼠心肌梗死模型中进行心肌内注射后，F-EPCs与OVX-EPCs可分泌更高水平的促血管生成因子、更低水平的促炎细胞因子，并展现出更优异的心脏修复活性。表观遗传测序结果显示，与雌性及去卵巢雌性内皮祖细胞相比，雄性内皮祖细胞中基因抑制性标记组蛋白H3赖氨酸9三甲基化（H3K9me3）的结合位点存在显著差异，尤其是在关键血管生成基因与促炎基因的转录起始位点处。本研究揭示，内皮祖细胞的功能性别二态性部分由促炎且抗血管生成基因CCL3的差异表观遗传调控所介导，该调控过程由组蛋白甲基转移酶G9a/Ehmt2对H3K9me3的修饰所调控。本研究强调了在基于祖细胞的组织修复中，考虑供体细胞性别的重要性。整体实验设计：旨在探究调控内皮祖细胞性别二态性心脏修复特性的雌激素非依赖表观遗传机制。