[Melatonin alleviates cardiomyocyte necroptosis in diabetic mice by inhibiting the STING signaling pathway].

摘要

OBJECTIVES: To investigate the protective effect of melatonin against diabetic cardiomyopathy (DCM) and whether melatonin regulates cardiomyocyte necroptosis and inflammatory response through the stimulator of interferon genes (STING) signaling pathway. METHODS: C57 mouse models of DCM induced by streptozotocin (STZ) injection were given an intraperitoneal injection of saline or melatonin (n=6), and 24 h later blood and myocardial samples were collected from the mice for analysis. A cell model of DCM was established in HL-1 cells by high glucose treatment (33 mmol/L). Pathological changes in myocardial tissue of the mice were observed using HE staining. Immunofluorescence staining and Western blotting were used to detect the key necroptosis proteins, and the pro-inflammatory factors including IL-1β, IL-6, and TNF-α were detected with Western blotting and ELISA to evaluate cell death and inflammation. The expression levels of the proteins associated with STING pathway activation (P-IRF3 and P-P65) were detected using immunohistochemistry and Western blotting. RESULTS: In the diabetic mice and cell models of DCM, the STING signaling pathway was activated with significantly increased protein expressions of STING and P-IRF3. The myocardial tissues of DCM mice showed increased inflammatory infiltration with upregulated serum and myocardial levels of IL-1β, IL-6, and TNF-α and increased levels of necroptosis-related proteins P-MLKL, P-RIPK1, and P-RIPK3. Treatment with melatonin significantly inhibited the activation of the STING signaling pathway and reduced the expression levels of inflammatory factors and necroptosis-related proteins, and the use of the STING agonist DMXAA significantly attenuated the protective effect of melatonin. CONCLUSIONS: Melatonin effectively alleviates cardiomyocyte necroptosis and inflammatory response in DCM by inhibiting the STING signaling pathway. 目的: 探讨褪黑素（Mel）对糖尿病心肌病（DCM）的保护作用，并阐明其是否通过干扰素基因刺激因子（STING）信号通路调控心肌细胞坏死性凋亡和炎症反应。方法: 采用链脲佐菌素（STZ）诱导的2型糖尿病小鼠模型建立体内DCM模型;同时，采用高糖（HG，33mmol/L）处理的HL-1细胞建立体外DCM模型。实验动物分为对照组（Sham），糖尿病模型组（DM）和褪黑素治疗组（DM+Mel），6只/组。通过HE染色观察心肌组织的病理学变化。采用免疫荧光染色与Western blotting检测P-RIPK1，P-RIPK3，P-MLKL等坏死性凋亡的关键蛋白，Western blotting和ELISA检测白细胞介素-1β（IL-1β），白细胞介素-6（IL-6），肿瘤坏死因子-α（TNF-α）等促炎因子评估细胞死亡和炎症水平。通过免疫组化和Western blotting检测STING信号通路激活相关蛋白（如P-IRF3和P-P65）水平。结果: 与Sham组相比，DM组STING信号通路激活，STING，P-IRF3蛋白表达水平显著升高（P<0.05），心肌组织炎症浸润增加，血清及心肌炎症因子，IL-1β，IL-6及TNF-α表达上调（P<0.05），坏死性凋亡相关蛋白P-MLKL，P-RIPK1，P-RIPK3水平升高（P<0.05）。DM+Mel组STING信号通路被抑制，STING，P-IRF3蛋白表达水平下降（P<0.05），炎症因子及坏死性凋亡相关蛋白IL-1β，IL-6，TNF-α及P-MLKL，P-RIPK1，P-RIPK3表达下降（P<0.05）。而使用STING激动剂DMXAA可以部分逆转褪黑素的保护作用（P<0.05）。结论: 褪黑素通过抑制STING信号通路，有效减轻糖尿病心肌病中的心肌细胞坏死性凋亡和炎症反应，从而发挥心脏保护作用。.