Connexin 43-autophagy loop in the podocyte injury of diabetic nephropathy
Connexin 43-autophagy loop in the podocyte injury of diabetic nephropathy
复制标题
连接蛋白43-自噬环在糖尿病肾病足细胞损伤中的作用
DOI：
10.3892/ijmm.2019.4335
复制
发表时间：
2019-11-01
影响因子：
5.4
通讯作者：
Zhang, Aiqing
中科院分区：
文献类型：
--
作者：
Ji, Jialing;Zhao, Yajie;Zhang, Aiqing
减少足细胞损伤是控制蛋白尿的关键策略，而蛋白尿是糖尿病肾病（DN）的主要早期临床表现。自噬通量受损是DN足细胞损伤的主要机制。本研究的目的是阐明连接蛋白43 （Cx43）对足细胞损伤中自噬通量受损的影响，并探讨其在DN中的作用分子机制。采用streptozocin （STZ）建立sd大鼠DN动物模型。足细胞在含有缓冲液或高糖（HG; 30 mM）的培养基中孵育不同的时间。采用Annexin V/PI法、免疫荧光染色法、western blotting法和RNA干扰法检测足细胞损伤机制。在体内，建立stz诱导DN大鼠Cx43基因敲低或不敲低，观察Cx43在自噬通量和足细胞损伤中的作用。我们观察到HG诱导足细胞损伤，伴随Cx43表达增加和自噬通量受损，LC3II/LC3I和p62的积累证明了这一点。有趣的是，Cx43表达的沉默通过抑制雷帕霉素途径的哺乳动物靶点，改善了自噬通量损伤，减少了足细胞损伤。此外，自噬通量受损也阻断了Cx43的降解。体外研究表明，与对照组相比，hg诱导的足细胞损伤中，Annexin V/ pi阳性足细胞数量增加，自噬通量受损，Cx43表达增加。Cx43的下调也证实了Cx43对自噬通量受损和足细胞损伤的致病作用。本研究提供了初步证据，表明Cx43与自噬通量受损的相互依赖是DN足细胞损伤的一种新机制。因此，cx43 -自噬环是治疗DN的潜在相关治疗靶点。
The reduction of podocyte injury is a key strategy in controlling proteinuria, which is the main early clinical manifestation of diabetic nephropathy (DN). Impaired autophagic flux is the primary mechanism responsible for podocyte injury in DN. The aim of the present study was to elucidate the effect of connexin 43 (Cx43) on impaired autophagic flux in podo-cyte injury and to explore its molecular mechanism of action in DN. Sprague-Dawley rats were administered streptozocin (STZ) to construct a DN animal model. Podocytes were incubated in media containing either buffer or high glucose (HG; 30 mM) for variable time periods. The podocytes were then examined and the mechanism of injury was investigated using an Annexin V/PI assay, immunofluorescence staining, western blotting, and RNA interference. In vivo, STZ-induced DN rats with or without Cx43 knockdown were established to observe the role of Cx43 in autophagic flux and podocyte injury. We observed that HG induced podocyte injury, accompanied by increases in Cx43 expression and impaired autophagic flux, as evidenced by the accumulation of LC3II/LC3I and p62. Interestingly, the silencing of Cx43 expression ameliorated autophagic flux impairment and reduced podocyte injury via suppression of the mammalian target of rapamycin pathway. Furthermore, impaired autophagic flux also blocked the degradation of Cx43. In vitro studies indicated that higher numbers of Annexin V/PI-positive podocytes, impaired autophagic flux and increased Cx43 expression were observed in HG-induced podocyte injury relative to the control group. The pathogenic effect of Cx43 on impaired autophagic flux and podocyte injury was also confirmed by Cx43 knockdown. The present study provided preliminary evidence indicating that the interdependence of Cx43 and impaired autophagic flux represents a novel mechanism of podocyte injury in DN. Hence, the Cx43-autophagy loop is a potentially relevant therapeutic target for the treatment of DN.