Sex-related differences in cardiac mitochondrial response to inflammation

败血症、创伤和缺血后会造成心脏损伤。由这些损伤引发的急性炎症 损害线粒体，这是心脏损伤严重程度的关键决定因素。而性别二形性影响 这些损伤的后果，没有关于性别特异性线粒体反应的信息 急性炎症。我们观察到，TNFa严重抑制心脏功能，而女性心脏 对TNFa引起的心功能不全具有抵抗力。我们还发现了线粒体性能的性别差异 在暴露于TNFa或内毒素的心肌细胞中。因此，我们推断，性别特异的线粒体对 炎症是心脏损害中性别差异的潜在机制。线粒体连接蛋白-43 (Cx43)和Caveolin-3(Cav3，小窝形成所必需的结构蛋白)与线粒体有关 对缺血心脏的保护。到目前为止，线粒体(Mito)Cx43和mitoCav3都没有被研究过 依赖性别的线粒体对炎症的弹性。我们最近的研究表明，mitoCx43及其 较小的亚型Gja1-20k在性别相关的线粒体反应和雌激素介导的心脏中发挥作用 急性缺血/再灌流后的保护作用。我们的初步工作进一步表明：1)更好的心脏 功能与较高水平的mitoCx43磷酸化(p-Cx43)、mitoGja1-20k和mitoCav3相关 在TNFa或LPS刺激后，女性心脏比男性心脏；2)女性心肌细胞有更好的 线粒体在TNFa或LPS暴露下的表现优于男性；3)Cx43或Cav3基因被敲除会受损 4)17b-雌二醇(E_2)治疗改善成肌细胞线粒体功能 线粒体功能增加，p-Cx43和mitoGja1-20k增加；消融心脏Cx43可消除E2诱导的 5)E_2增强Cx43和Cav3与心肌细胞的结合 雌激素受体(ER)并促进心肌线粒体Cx43-Cav3的相互作用。我们假设 女性心脏线粒体抵抗急性炎症诱导的损伤，通过ER(S)激活-增加 线粒体Gja1-20k、p-Cx43和Cx43-Cav3与男性的相互作用。在本建议中 研究中，我们将采用内毒素或盲肠结扎穿刺法(CLP)诱导的脓毒症模型，探讨其作用机制。 MitoCx43和mitoCav3在调节性别特异性心肌线粒体保护中的作用。我们将确定角色 Cx43(Aim 1)、Cav3及其相互作用(Aim 2)在维持心肌线粒体健康和性别中的作用 急性炎症时线粒体弹性的差异；并评估Gja1-1的治疗潜力 脂多糖或CLP诱导的败血症心肌病中的20K负载外切体(AIM 3)。我们期待着这种新颖的方法 利用工程外切体将Gja1-20k特异性地运送到心肌细胞将改善线粒体 败血症心肌病的保存和心功能。拟议研究的完成将带来新的 关于线粒体对急性炎症的性别特异性差异反应的见解，并提供了 开发治疗急性炎症引起的男女心肌病的新方法。

Cardiac damage occurs following sepsis, trauma, and ischemia. Acute inflammation triggered by these injuries impairs mitochondria, a key determinant for the severity of cardiac damage. While sex dimorphism impacts consequences of these injuries, no information is available regarding sex-specific mitochondrial responses to acute inflammation. We have observed that TNFa acutely depresses cardiac function and female hearts are resistant to TNFa-induced cardiac dysfunction. We have also found sex differences in mitochondrial performance in cardiomyocytes exposed to TNFa or LPS. Thus, we reason that sex-specific mitochondrial responses to inflammation is the underlying mechanism for sex disparities in cardiac damage. Mitochondrial connexin-43 (Cx43) and caveolin-3 (Cav3, a structural protein essential for caveolae formation) are involved in mitochondrial protection in the ischemic heart. To date, neither mitochondrial (mito)Cx43 nor mitoCav3 has been studied for sex-dependent mitochondrial resilience to inflammation. Our recent study has suggested that mitoCx43 and its smaller isoform, Gja1-20k, play a role in sex-related mitochondrial responses and estrogen-mediated cardiac protection following acute ischemia/reperfusion. Our preliminary work has further indicated: 1) better cardiac function is associated with higher levels of mitoCx43 phosphorylation (p-Cx43), mitoGja1-20k and mitoCav3 in female hearts than in male hearts following TNFa or LPS challenge; 2) female cardiomyocytes have better mitochondrial performance than male ones upon TNFa or LPS exposure; 3) knockdown of Cx43 or Cav3 impairs mitochondrial function in myoblasts subjected to TNFa or LPS; 4) 17b-estradiol (E2) treatment improves mitochondrial function with increased p-Cx43 and mitoGja1-20k; ablation of cardiac Cx43 abolishes E2-elicited mitochondrial protection in cardiomyocytes exposed to TNFa; and 5) E2 enhances Cx43 and Cav3 binding to estrogen receptor (ER)a and promotes Cx43-Cav3 interaction in cardiac mitochondria. We hypothesize that female heart mitochondria are resistant to acute inflammation-induced damage via ER(s) activation-increased mitochondrial Gja1-20k, p-Cx43 and Cx43-Cav3 interaction in comparison to the male ones. In this proposed study, we will employ LPS- or cecal ligation puncture (CLP)-induced sepsis models to explore the role of mitoCx43 and mitoCav3 in regulating sex-specific cardiac mitochondrial protection. We will determine the roles of Cx43 (Aim 1), Cav3 and their interaction (Aim 2) in maintaining cardiac mitochondrial health and in sex differences of mitochondrial resilience upon acute inflammation; and assess the therapeutic potential of Gja1- 20k-loaded exosomes in LPS- or CLP-induced septic cardiomyopathy (Aim 3). We expect that novel approach using engineered exosomes to specifically deliver Gja1-20k to cardiomyocytes will improve mitochondrial preservation and cardiac function in septic cardiomyopathy. Completion of the proposed study will bring novel insights about sex-specific differential mitochondrial responses to acute inflammation and offer the basis of developing novel approaches in treating acute inflammation-caused cardiomyopathy in both sexes.