Feng Jianan, Li Han, Wang Shixiang
Department of Nephrology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China.
Front Pharmacol. 2022 Dec 15;13:1027597. doi: 10.3389/fphar.2022.1027597. eCollection 2022.
The gasotransmitter hydrogen sulfide (HS) plays important physiological and pathological roles in the cardiovascular system. However, the involvement of HS in recovery from uremic cardiomyopathy (UCM) remains unclear. This study aimed to determine the therapeutic efficacy and elucidate the underlying mechanisms of HS in UCM. A UCM model was established by 5/6 nephrectomy in 10-week-old C57BL/6 mice. Mice were treated with sodium hydrosulfide (NaHS, HS donor), L-cysteine [L-Cys, cystathionine gamma-lyase (CSE) substrate], and propargylglycine (PPG, CSE inhibitor). Treatment of H9C2 cardiomyocytes utilized different concentrations of uremic serum, NaHS, PPG, and PI3K inhibitors (LY294002). Mouse heart function was assessed by echocardiography. Pathological changes in mouse myocardial tissue were identified using hematoxylin and eosin and Masson's trichrome staining. Cell viability was assessed using the Cell Counting Kit-8. The protein expressions of CSE, p-PI3K, PI3K, p-PKB, PKB, p-mTOR, mTOR, and autophagy-related markers (Beclin-1, P62, and LC3) were detected using Western blotting. We found that NaHS and L-Cys treatment attenuated myocardial disarray, fibrosis, and left ventricular dysfunction in UCM mice. These abnormalities were further aggravated by PPG supplementation. Enhanced autophagy and decreased phosphorylation of PI3K, PKB, and mTOR protein expression by UCM were altered by NaHS and L-Cys treatment. , uremic serum increased overactive autophagy and decreased the phosphorylation levels of PI3K, PKB, and mTOR in cardiomyocytes, which was substantially exacerbated by endogenous HS deficiency and attenuated by pre-treatment with 100 µm NaHS. However, the protective effects of NaHS were completely inhibited by LY294002. These findings support a protective effect of HS exerted against UCM by reducing overactive autophagy through activation of the PI3K/PKB/mTOR pathway.
气体信号分子硫化氢（HS）在心血管系统中发挥着重要的生理和病理作用。然而，HS在尿毒症性心肌病（UCM）恢复过程中的作用仍不清楚。本研究旨在确定HS对UCM的治疗效果并阐明其潜在机制。通过对10周龄C57BL/6小鼠进行5/6肾切除建立UCM模型。小鼠分别用硫氢化钠（NaHS，HS供体）、L-半胱氨酸[L-Cys，胱硫醚γ-裂解酶（CSE）底物]和炔丙基甘氨酸（PPG，CSE抑制剂）进行治疗。使用不同浓度的尿毒症血清、NaHS、PPG和PI3K抑制剂（LY294002）处理H9C2心肌细胞。通过超声心动图评估小鼠心脏功能。使用苏木精-伊红和Masson三色染色法鉴定小鼠心肌组织的病理变化。使用细胞计数试剂盒-8评估细胞活力。采用蛋白质印迹法检测CSE、p-PI3K、PI3K、p-PKB、PKB、p-mTOR、mTOR及自噬相关标志物（Beclin-1、P62和LC3）的蛋白表达。我们发现，NaHS和L-Cys治疗可减轻UCM小鼠的心肌排列紊乱、纤维化和左心室功能障碍。PPG补充会进一步加重这些异常。UCM导致的自噬增强以及PI3K、PKB和mTOR蛋白表达磷酸化水平降低，经NaHS和L-Cys治疗后发生改变。尿毒症血清会增加心肌细胞中过度活跃的自噬，并降低PI3K、PKB和mTOR的磷酸化水平，内源性HS缺乏会使其显著加剧，而100µm NaHS预处理可使其减轻。然而，LY294002完全抑制了NaHS的保护作用。这些发现支持HS通过激活PI3K/PKB/mTOR途径减少过度活跃的自噬，从而对UCM发挥保护作用。
