O-GlcNAc-modified SNAP29 inhibits autophagy-mediated degradation via the disturbed SNAP29-STX17-VAMP8 complex and exacerbates myocardial injury in type I diabetic rats.
O-GlcNAc-modified SNAP29 inhibits autophagy-mediated degradation via the disturbed SNAP29-STX17-VAMP8 complex and exacerbates myocardial injury in type I diabetic rats.
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O-GlcNAc 修饰的 SNAP29 通过受干扰的 SNAP29-STX17-VAMP8 复合物抑制自噬介导的降解，并加剧 I 型糖尿病大鼠的心肌损伤
DOI：
10.3892/ijmm.2018.3866
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发表时间：
2018-12
影响因子：
5.4
通讯作者：
Hu J
中科院分区：
文献类型：
--
作者：
Huang L;Yuan P;Yu P;Kong Q;Xu Z;Yan X;Shen Y;Yang J;Wan R;Hong K;Tang Y;Hu J
O-连接的β-N-乙酰葡萄糖胺（O-GlcNAc）修饰和自噬与糖尿病心肌损伤有关，但这两个过程之间的分子机制尚未完全阐明。本研究的目的是阐明O-GlcNAc修饰的突触体相关蛋白29（SNAP 29）在糖尿病心肌损伤中对自噬的分子调控。通过腹腔注射链脲佐菌素（STZ; 55 mg/kg）建立I型糖尿病大鼠模型。在STZ诱导后8周，在大鼠中观察到O-GlcNAc修饰和自噬标志物微管相关蛋白1轻链3α II/I和P62的蓄积显著增加，表明自噬通量受到抑制。随后，选择性O-GlcNAc酶抑制剂thiamet G增加了O-GlcNAc修饰的水平，这进一步破坏了自噬通量;心脏舒张功能恶化，如超声心动图显示的左心室充盈峰值速度/心房收缩流速峰值速度比增加所示;并加剧了心肌异常，其特征在于心肌细胞解体以及脂肪和间质纤维化积累。相比之下，6-重氮-5-氧代-L-正亮氨酸，葡萄糖胺果糖-6-磷酸氨基转移酶异构化1的抑制剂，作为O-GlcNAc拮抗剂，并降低了O-GlcNAc修饰的水平，这维持了自噬通量并改善了心脏舒张功能。在体外，高葡萄糖（25 mM）用于刺激原代新生大鼠心肌细胞（NRCM）。与糖尿病大鼠的心肌一致，在NRCM中也显示SNAP 29的O-GlcNAc修饰负调节自噬通量。短发夹RNA干扰溶酶体相关膜蛋白（LAMP 2）和自噬抑制剂3-甲基腺嘌呤的应用表明，高糖抑制自噬介导的降解，而不是影响自噬的初始阶段。最后，使用免疫共沉淀来确定O-GlcNAc修饰的底物蛋白SNAP 29的作用，其在疾病进展期间充当SNAP 29-突触融合蛋白-17（STX 17）-囊泡相关膜蛋白8（VAMP 8）复合物。据我们所知，本研究首次证明SNAP 29是O-GlcNAc底物，并且O-GlcNAc修饰的SNAP 29的增加抑制SNAP 29-STX 17-VAMP 8复合物的形成，从而抑制自噬的降解并加剧I型糖尿病大鼠的心肌损伤。
The O-linked β-N-acetylglucosamine (O-GlcNAc) modification and autophagy are associated with diabetic myocardial injury, however, the molecular mechanisms between the two processes remain to be fully elucidated. The purpose of the present study was to elucidate the molecular regulation of autophagy by O-GlcNAc-modified synaptosomal-associated protein 29 (SNAP29) in diabetic myocardial injury. A rat model of type I diabetes was established via intraperitoneal injection of streptozotocin (STZ; 55 mg/kg). Significant increases in the O-GlcNAc modification and accumulation of the autophagy markers microtubule-associated protein 1 light chain 3α II/I and P62, which suggest that autophagic flux is inhibited, were observed in rats 8 weeks following STZ induction. Subsequently, the selective O-GlcNAcase inhibitor, thiamet G, increased the level of O-GlcNAc modification, which further disrupted autophagic flux; deteriorated cardiac diastolic function, as indicated by an increased left ventricular filling peak velocity/atrial contraction flow peak velocity ratio shown by echocardiography; and exacerbated myocardial abnormalities, as characterized by cardiomyocyte disorganization and fat and interstitial fibrosis accumulation. By contrast, 6-diazo-5-oxo-L-norleucine, an inhibitor of glucosamine fructose-6-phosphate aminotransferase isomerizing 1, acted as an O-GlcNAc antagonist and reduced the level of O-GlcNAc modification, which maintained autophagic flux and improved cardiac diastolic function. In vitro, high glucose (25 mM) was used to stimulate primary neonatal rat cardiomyocytes (NRCMs). Consistent with the myocardium of diabetic rats, it was also shown in the NRCMs that O-GlcNAc modification of SNAP29 negatively regulated autophagic flux. The application of the short hairpin RNA interference lysosome-associated membrane protein (LAMP2) and the autophagy inhibitor 3-methyladenine demonstrated that high glucose inhibited autophagy-mediated degradation rather than affected the initial stage of autophagy. Finally, co-immunoprecipitation was used to determine the role of the O-GlcNAc-modified substrate protein SNAP29, which acted as an SNAP29-syntaxin-17 (STX17)-vesicle-associated membrane protein 8 (VAMP8) complex during disease progression. The present study is the first, to the best of our knowledge, to demonstrate that SNAP29 is an O-GlcNAc substrate and that an increase in O-GlcNAc-modified SNAP29 inhibits SNAP29-STX17-VAMP8 complex formation, thereby inhibiting the degradation of autophagy and exacerbating myocardial injury in type I diabetic rats.
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影响因子：
64.5
作者：
Pekkurnaz G;Trinidad JC;Wang X;Kong D;Schwarz TL
通讯作者：
Schwarz TL
影响因子：
64.8
作者：
Diao, Jiajie;Liu, Rong;Rong, Yueguang;Zhao, Minglei;Zhang, Jing;Lai, Ying;Zhou, Qiangjun;Wilz, Livia M.;Li, Jianxu;Vivona, Sandro;Pfuetzner, Richard A.;Brunger, Axel T.;Zhong, Qing
通讯作者：
Zhong, Qing
影响因子：
9.3
作者：
Chen ZC;Cheng YZ;Chen LJ;Cheng KC;Li Y;Cheng J
通讯作者：
Cheng J
影响因子：
7.2
作者：
Li, Huan-Ting;Wu, Xiao-Dong;Wang, Jiping
通讯作者：
Wang, Jiping
DOI：
10.2147/dmso.s30968
发表时间：
2013
期刊：
Diabetes, metabolic syndrome and obesity : targets and therapy
影响因子：
--
作者：
Chavali V;Tyagi SC;Mishra PK
通讯作者：
Mishra PK