Yang Zijun, Guo Zuishuang, Dong Ji, Sheng Shifeng, Wang Yulin, Yu Lu, Wang Hongru, Tang Lin
Department of Nephropathy, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.
Henan Medical College, Zhengzhou, China.
Front Pharmacol. 2018 Aug 10;9:900. doi: 10.3389/fphar.2018.00900. eCollection 2018.
The microRNA (mir)-374a has been implicated in several types of human cancer; however, its role in diabetic nephropathy (DN) remains unclear. Monocyte chemoattractant protein (MCP)-1 is a chemokine that recruits macrophages to inflammatory sites and is important for the development and progression of DN. However, the relationship between miR-374a and MCP-1 in DN is unknown. We addressed this in the present study by examining the expression of these factors in kidney tissue samples from DN patients and through loss- and gain-of-function experiments using HK2 human renal tubular epithelial cells. We found that miR-374a was downregulated whereas MCP-1 was upregulated in DN tissue. A bioinformatics analysis revealed that MCP-1 is a putative target of miR-374a. To confirm this relationship, HK2 cells treated with normal glucose (5.6 mmol/l D-glucose), high glucose (HG) (30 mmol/l D-glucose), or high osmotic pressure solution (5.6 mmol/l D-glucose + 24.4 mmol/l D-mannitol) were transfected with miR-374a mimic or inhibitor. miR-374a mimic reduced MCP-1 mRNA expression and migration of co-cultured U937 cells, whereas miR-374a inhibition had the opposite effects. Additionally, interleukin-6 and -18 and tumor necrosis factor-α levels were downregulated by transfection of miR-374a mimic. On the other hand, MCP-1 overexpression reversed the inhibitory effects of miR-374a in HK2 cells. Thus, miR-374a suppresses the inflammatory response in DN through negative regulation of MCP-1 expression. These findings suggest that therapeutic strategies that target the miR-374a/MCP-1 axis can be an effective treatment for DN.
微小RNA（miR）-374a已被证实与多种人类癌症有关；然而，其在糖尿病肾病（DN）中的作用仍不清楚。单核细胞趋化蛋白（MCP）-1是一种趋化因子，可将巨噬细胞募集到炎症部位，对DN的发生和发展至关重要。然而，miR-374a与DN中MCP-1之间的关系尚不清楚。在本研究中，我们通过检测DN患者肾组织样本中这些因子的表达，并利用HK2人肾小管上皮细胞进行功能缺失和功能获得实验，来解决这一问题。我们发现，DN组织中miR-374a表达下调，而MCP-1表达上调。生物信息学分析显示，MCP-1是miR-374a的潜在靶点。为了证实这种关系，用正常葡萄糖（5.6 mmol/L D-葡萄糖）、高糖（HG）（30 mmol/L D-葡萄糖）或高渗溶液（5.6 mmol/L D-葡萄糖 + 24.4 mmol/L D-甘露醇）处理的HK2细胞被转染了miR-374a模拟物或抑制剂。miR-374a模拟物降低了MCP-1 mRNA表达以及共培养的U937细胞的迁移，而抑制miR-374a则产生相反效果。此外，转染miR-374a模拟物可下调白细胞介素-6和-18以及肿瘤坏死因子-α水平。另一方面，MCP-1过表达逆转了miR-374a对HK2细胞的抑制作用。因此，miR-374a通过负调控MCP-1表达来抑制DN中的炎症反应。这些发现表明，针对miR-374a/MCP-1轴的治疗策略可能是治疗DN的有效方法。
