Tbx3调控小鼠输尿管芽发育的作用及其分子机制研究

During normal mammalian embryo development, the occurrence of kidney originates from the formation of ureteric bud. Here, interactions between prespecified metanephric mesenchyme cells and the adjacent ureteric bud trigger the formation of functional nephron. However, the molecular mechanism underlying the development of ureteric bud need to be further elucidated. Tbx3 belongs to T-box family, playing crucial roles in the process of cell fate decision and organogenesis. Our previous studies found that Tbx3 was specifically expressed in the epithelial cells of ureteric bud during mouse kidney development, but its roles is not clear. To investigate the function of Tbx3 in ureteric bud development, including branching, elongation and differentiation, we will perform morphological and functional analysis of Tbx3 conditional knockout mice. For further elucidating the mechanisms underlying the role of Tbx3 playing in the maintenance of kidney development, we will perform transcriptome and promoter activity analysis, which will provide a theoretical basis for the development of congenital renal hypoplasia, the pathogenesis and treatment of acquired renal disease.

肾脏的发生起始于输尿管芽的形成，输尿管芽通过与相邻细胞相互作用诱导功能性肾单位的形成，其发育缺陷可导致肾脏先天性发育不良，甚至形成“孤立肾”。目前，人们还不十分清楚输尿管芽维持其发育的分子机制。Tbx3是在胚胎发育中参与细胞命运决定以及器官形成的重要转录因子。在荧光报告基因小鼠的基础上，我们实验室通过初步研究发现，Tbx3在胚胎期肾脏发育过程中特异性表达于输尿管芽上皮细胞，但其作用及分子机制尚不清楚。针对以上问题，本项目拟在建立Tbx3输尿管芽条件性敲除小鼠的基础上，应用形态学、功能学等检测手段，研究Tbx3在调控输尿管芽分叉、延伸以及分化等方面的作用。同时，进一步结合转录组测序、ChIP-seq、体内功能验证等方法，寻找在该过程中受Tbx3调控的下游基因，深入讨论Tbx3在输尿管芽发育中的分子机制，为先天性肾脏发育不全、后天性肾脏疾病发生机制以及人类肾脏疾病的治疗提供理论借鉴。

肾脏的发生起始于输尿管芽的形成，输尿管芽通过与相邻细胞相互作用诱导功能性肾单位的形成，其发育缺陷可导致肾脏先天性发育不良，甚至形成“孤立肾”。目前，人们还不十分清楚输尿管芽维持其发育的分子机制。Tbx3是在胚胎发育中参与细胞命运决定以及器官形成的重要转录因子。在荧光报告基因小鼠的基础上，申请人前期研究发现，Tbx3在胚胎期肾脏发育过程中特异性表达于输尿管芽上皮细胞，但其作用及分子机制尚不清楚。本课题在Tbx3-2A-GFP小鼠的基础上，借助免疫组化荧光染色、荧光定量PCR等技术，研究发现Tbx3特异性表达于输尿管芽、集合管及其间质细胞；借助Tbx3输尿管芽条件性敲除小鼠，本课题研究发现Tbx3的表达缺失可降低输尿管芽细胞增殖，但并不影响完整肾脏结构的形成及其肾功能。