AVPR2在骨重建中的作用及生物学效应

Nephrogenic diabetes insipidus (NDI) is caused by mutations in arginine vasopressin type 2 receptor (AVPR2), short stature is one of common features in NDI cases. AVPR2 is active functionally in regulating bone mass.The study suggests AVPR2 may play an important role in bone remodeling and be involved in the important pathophysiological mechanisms of short stature. In previous work, we reported a Chinese family with NDI caused by a novel 22.1-kb deletion comprising the entire AVPR2 locus and part of the Rho GTPase-activating protein 4 (ARHGAP4) locus and short stature is the main clinical characterization. We study that MC3T3-E1 cell and RAW264.7 cell expressed AVPR2 as did the kidney. In present study, to illuminate the biological mechanism of AVPR2 in the development of bone remodeling, we will find and validate more genes that were detected by the whole genome expression profiling and try to confirm which genes are really controlled by the expression of AVPR2. And we will identify and analysis the function of proteins which are encoded by the genes that are effected by AVPR2. Then, we will evaluate the effect of AVPR2 on the cell biological features . Lastly, by using GST-pulldown and systems biology methods, we will find the binding protein of AVPR2. In order to clarify the biological effects of AVPR2 during the development of bone remodeling and short stature, and identify potential diagnostic markers and intervention targets.

AVPR2是肾性尿崩症的致病基因，身材矮小是尿崩症主要临床特征之一，最新研究显示AVPR2是参与骨重建的重要基因。由于骨发育进行生长、骨重建，骨重建的异常可导致身材矮小，因此AVPR2可能影响骨重建过程与功能，在骨发育过程中发挥直接作用。前期研究中，我们在一个X连锁的肾性尿崩症家系中发现包含AVPR2基因和部分ARHGAP4基因的一个新的22.1kb大片段缺失，身材矮小是该家系的主要临床特征，PCR证实AVPR2在MC3T3-E1和RAW264.7中高表达，我们拟通过基因功能学等相关研究，系统地寻找与受AVPR2调控的下游基因，研究AVPR2表达与否对骨重建相关细胞的影响，筛选可能与AVPR2相互作用的分子，构建与AVPR2相关的信号通路及基因调控网络；鉴定、分析受AVPR2调控基因所编码的蛋白，研究AVPR2介导骨重建的分子机制，以期阐明AVPR2在骨重建过程及身材矮小发生的生物学效应。

AVPR2是肾性尿崩症的致病基因，身材矮小和智力障碍是尿崩症主要临床特征，本研究中，在一个中国汉族NDI家系中，发现一个新的包括整个AVPR2基因和部分ARHGAP4基因的22.1kb大片段缺失突变，并对家系中的高危胎儿进行产前基因诊断，丰富AVPR2基因突变图谱；应用 RNAi 进行抑制体外培养细胞AVPR2 表达的实验后，我们分析了 AVPR2对骨分化基因 Runx2、Osx、Bsp、Atf4、Opn、Osteocalcin及相关细胞的影响；同时通过RNA-Seq技术进行全基因表达谱分析，发现 400个可能受AVPR2表达影响的基因，初步构建了AVPR2 与其下游基因参与疾病发生机制的通路和调控网络；同时新增对多个骨骼发育异常家系进行相关致病基因的突变分析，发现多个新的致病位点，并建立中国汉族人群的相关研究疾病的遗传图谱。这些研究结果已达到预期目标，阐明AVPR2基因功能及其在疾病发生发展过程中的作用提供了基础，以及致病位点检测为骨骼发育的致病机制提供良好的遗传基础。