肢芽Hnrnpk敲除抑制间质祖细胞增殖导致小鼠四肢畸形的机制研究

四肢畸形是第二大常见先天性疾病，致病机制未完全阐明。我们前期基于家系发现hnRNPK介导LMBR1基因点突变导致多指发生（Genet Med, IF 8.683, 2020），但hnRNPK是否调控四肢骨发育参与四肢畸形发生尚未可知。预实验发现肢芽（Prx1-Cre）Hnrnpk条件性敲除小鼠出现四肢短小畸形、间质祖细胞 （Mesenchymal Progenitor Cells，MPCs）增殖抑制。RNA测序提示Hnrnpk敲除致p53通路活性异常上调。我们提出Hnrnpk敲除可能通过激活p53通路抑制MPCs增殖导致四肢畸形的科研假设。本项目拟通过已构建的肢芽Hnrnpk敲除小鼠模型，体外培养MPCs，进一步探究hnRNPK与p53通路蛋白互作的分子机制，验证p53通路抑制能改善Hnrnpk敲除小鼠的畸形表型，阐明hnRNPK缺失导致四肢畸形的作用机制，为四肢畸形的防治提供实验依据。

Limb deformity is the second most common congenital disease in human beings, and the pathogenic mechanism has not been fully elucidated. We have demonstrated that hnRNPK mediated LMBR1 point mutation leading to polydactyly (Genet Med, IF 8.683, 2020) based on pedigrees. However, it is not known whether hnRNPK regulates the development of limb bone and participates in the occurrence of limb deformities. The pre-experiment showed that conditional knockout Hnrnpk in limb bud of mice using Prx1-Cre showed limb shortness and inhibited proliferation of mesenchymal progenitor cells （MPCs）. RNA sequencing showed that Hnrnpk knockout led to abnormal activation of p53 pathway. We propose the scientific hypothesis that Hnrnpk knockout may inhibit the proliferation of MPCs and lead to limb malformations by activating p53 pathway. This project intends to further explore the molecular mechanism of the interaction between hnRNPK and p53 pathway proteins by transgenic mice with Hnrnpk knockout in limb bud and culturing limb bud MPCs in vitro, and to verify that p53 pathway inhibition can improve limb deformities in Hnrnpk knockout mice. This project will provide experimental basis for clarifying the mechanism of hnRNPK deficiency leading to limb deformities and for the prevention and treatment of limb deformities.