长链非编码RNA-Rik过表达导致肾脏发育异常的分子机制

先天性肾脏和尿路畸形（CAKUT）是儿童慢性肾脏病的主要类型。后肾发育异常是引发CAKUT关键原因，分子机制尚未完全阐明。后肾发育关键分子Bmp4突变可致CAKUT，转录因子Sox2可负性调控其表达。课题组预实验显示：①过表达长链非编码RNA-Rik（Rik）小鼠肾发育异常、输尿管芽分支减少；②无明确原因肾发育不良患儿肾组织BMP4表达降低；③过表达Rik促使邻近分子Bmp4表达降低，Sox2表达增高。据此提出假设：Rik通过结合Sox2，抑制Bmp4表达，导致肾发育异常。本项目拟开展：①检测CAKUT患儿Rik变异及病变肾脏Rik、SOX2、BMP4表达水平，确定三者是否存在关联；②在过表达Rik小鼠模型上，观察下调Rik和上调Bmp4对肾脏发育的影响，寻找最佳干预靶点及干预时间；③应用小鼠及细胞模型阐明Rik结合Sox2调控Bmp4的分子机制。项目的完成将为CAKUT防治提供新的思路。

Congenital anomalies of the kidney and urinary tract (CAKUT) is the main cause of chronic kidney disease in children. The metanephric development abnormality is the essential reason attributing to CAKUT, while the exactly molecular mechanism has not been fully clarified. Bmp4, the key molecular of metanephric development, when has mutation could cause CAKUT and is negatively regulated by transcription factor Sox2. Pre-experiment prompted: (1) lncRNA Rik (Rik)-overexpression could cause CAKUT and decrease ureteric bud branches in mice; (2) The expression of Bmp4 was reduced in renal tissues of CAKUT patients without apparent cause; (3) When Rik was overexpressed in vivo or vitro, the expression of Bmp4 was reduced as its neighboring molecule, while the expression of Sox2 was increased. Thus we hypothesize: Rik could combine Sox2 to regulate Bmp4 expression inducing renal development abnormality. This study proposes: (1) Detecting the Rik variation in CAKUT patients and expression of Rik, SOX2 and BMP4 in abnormal kidneys, analyzing the association of these three molecules as well; (2) Using Rik-overexpression mice model to observe the embryonic kidney phenotypes by knock down Rik or exogenous supplement of Bmp4; (3) Using in vivo and vitro studies to elucidate the mechanism of Rik binding Sox2 to regulate Bmp4. Completion of the project will reveal the new CAKUT mechanism.