miR-451-1500026H17RIK双负反馈介导IGF-1/MAPK信号途径调控DN系膜增生

Glomerular mesangial cell proliferation and extracellular matrix accumulation play important roles in diabetic nephropathy (DN). However, the mechanism is not fully clear. Our studies revealed that miRNA participated in DN (NO.30800534). Our recent study showed the there was a interaction between miR-451 and lncRNA 1500026H17RIK-double feed-back. Moreover, the inhibition of cell proliferation of miR-451 was reinforced by silence of 1500026H17RIK. Also, the DN related gene-IGF-1 which located near 1500026H17RIK was decreased in the si-1500026H17RIK mesangial cells.These suggested that miR-451-1500026H17RIK may regulate the mesangial cell proliferation by IGF-1 related pathway in DN. We will foused on the interaction between the double feed-back of miR-451 and 1500026H17RIK in mesangial cells and db/db mouse. Firstly, we will study the specific relationship of double feed-back between miR-451 and 1500026H17RIK in DN. Secondly, we will investigate the effects of the interaction between miR-451 and 1500026H17RIK on mesangial cell proliferation, extracellular matrix accumulation and the conditions of the DN mice. Finally, we will examine the role of the double feed-back of miR-451 and 1500026H17RIK on IGF-1/MAPK signal pathway in DN. Collectively this project may help to elucidate the physiopathological mechanism of DN, and provide a new insight into the prevention and treatment of DN.

肾小球系膜增生是糖尿病肾病(DN)的重要原因，但确切机制尚不清楚。我们发现miRNA参与DN发生（NO.30800534），miR-451抑制DN系膜增生，近期实验发现DN时miR-451与lncRNA 1500026H17RIK存在双负反馈，且系膜细胞沉默1500026H17RIK可加强miR-451的细胞增殖抑制作用，同时使1500026H17RIK 毗邻的DN相关基因IGF-1表达下降，提示miR-451-1500026H17RIK可能通过IGF-1相关途径参与DN系膜增生。本项目以miR-451-1500026H17RIK双负反馈为切入点，以系膜细胞和db/db小鼠为研究对象，研究miR-451与1500026H17双负反馈；探讨此互作对系膜增生的影响；探究DN中此双负反馈对IGF-1/MAPK信号途径异常的调控。通过上述研究将有助于阐明DN系膜增生机制，为DN诊治提供新的突破点。

糖尿病肾病(diabetic nephropathy, DN)是糖尿病主要的微血管并发症之一, 也是终末期肾病的主要原因。DN的发病机制与多种因素密切相关, 肾小球系膜病变是 DN早期的重要改变之一, 包括系膜细胞增殖和细胞外基质合成增多。但DN发生发展的具体机制至今尚无定论。近年来，研究者发现长非编码RNA（long noncoding RNAs，lncRNAs）参与DN的发生发展，然而，lncRNA在DN系膜增生中的作用及机制目前未见明确报道。因此，本课题拟探讨lncRNA对DN系膜增生中的作用及机制。本课题采用定量实时聚合酶链反应（qRT-PCR）检测lncRNA 1500026H17Rik（简称150Rik）的表达水平；用EdU检测细胞增殖能力；用荧光素酶法和RNA免疫沉淀法检测150Rik与microRNA 451（miR-451）的关系；采用EdU、流式细胞仪、western blot等方法检测150Rik通过miR-451/胰岛素样生长因子1受体（IGF1R）/丝裂原活化蛋白激酶（p38MAPK）途径对细胞增殖的影响。结果发现，150Rik是一种进化上保守的lncRNA，在db/db-DN小鼠肾组织和高糖培养的系膜细胞中均显著上调。此外，150Rik的过表达或敲除可调节MCs中的细胞增殖。此外，150Rik与miR-451的相互作用是直接的和argonaute-2（Ago2）依赖的。结果还表明，在高糖条件下，150Rik的过表达通过miR-451/IGF1R/p38MAPK途径抑制MCs细胞增殖，而150Rik的敲除通过miR-451/IGF1R/p38MAPK途径促进细胞增殖。综上，高糖下lncRNA 150Rik 通过与miR-451和Ago2相互作用抑制miR-451的表达水平，从而调控miR-451靶基因IGF1R的表达，影响下游p38MAPK信号途径，从而影响DN系膜增生，为DN诊治提供实验室依据和新的突破点。