Foxp1的蛋白修饰对间充质干细胞衰老的影响

Mesenchymal stem cell (MSC) is one kind of widely distributed adult stem cell across body mesoderm. The aging of MSC is a major risk factor for degeneration of varied tissues. Recent study showed that controlling MSC senecence could reverse the aging of body tissues. Our previous investigation has revealed Foxp1 as a novel anti-aging protein. Foxp1 regulates MSC self-renewal ability by directly repressing p16 transcription. It also switches the MSC differentiation potency during aging process. Overexpression of Foxp1 in aged MSC could reverse their senescent characteristics. In addition, Foxp1 could form a complex with HDAC7 and undergo de-acetylation in regulating MSC senescence. And more, Foxp1 was phosphorylated at S468 under stimulation of ROS. Therefore, our aim is to dissect the influence of modification on Foxp1 transactivation activity by point mutation. And more, we are going to analyze their effect on MSC aging within Foxp1 point-mutated mice generated by CRISPR/CAS9 method in cooperationg with progeria reporter mice. Our research would pave new avenue to the treatment of aging-related degeneration diseases and provide new therapeutic targets.

间充质干细胞（MSC）是人体组织广泛分布的一种成体干细胞，它的衰老是许多组织退行性病变的重要原因。控制MSC的衰老是治疗退行性疾病的方案之一。我们前期的研究表明，转录因子Foxp1是一类新的抗衰老蛋白。它通过直接调控p16的转录，影响MSC的自我更新，也影响MSC衰老过程的分化潜能；升高Foxp1表达可以逆转MSC的衰老进程。我们还发现Foxp1在转录调控MSC的衰老过程中，还通过与HDAC7相互结合形成转录复合体，Foxp1结构域的赖氨酸位点发生去乙酰化，在ROS刺激下在S468发生磷酸化。我们将通过点突变的方式，在蛋白转录水平上检测这些位点的修饰对Foxp1的转录功能产生什么影响。通过CRISPR/CAS9制备这些点突变小鼠，结合早衰小鼠和报告基因小鼠模型，分析Foxp1的蛋白修饰对MSC衰老的作用。这些研究将为衰老等退行性疾病的治疗提供新的药物靶点。

间充质干细胞（MSC）是人体组织广泛分布的一种成体干细胞，它的衰老是许多组织退行性病变的重要原因。控制MSC的衰老是治疗退行性疾病的方案之一。我们前期的研究表明，转录因子Foxp1是一类新的抗衰老蛋白。它通过直接调控p16的转录，影响MSC的自我更新与衰老过程。我们通过此项目的实施，发现了Foxp1在转录调控MSC的衰老过程中，还通过与HDAC7相互结合形成转录复合体。我们在293T细胞中，通过共表达Foxp1与HDAC7蛋白，发现Foxp1-M，Foxp1-C端，能分别与HDAC7的C端结合。HDAC7能通过对Foxp1蛋白进行去乙酰化修饰，并提高Foxp1蛋白的稳定性，延缓其泛素化和降解。质谱分析发现，Foxp1蛋白上部分位点T204, T305, K385, K387, K421等位点发生乙酰化修饰。我们通过在人源胚胎干细胞当中引入这些位点的点突变并转分化为间充质干细胞，发现Foxp1 T204G点突变能明显促进MSCs的增殖，而K421G的突变能显著延缓MSCs衰老进程。通过CRISPR/Cas9制备这些点突变小鼠，结合早衰小鼠和报告基因小鼠模型，发现Foxp1的K421位点对延缓MSC衰老，以及整体器官的抗衰老作用，有非常大的价值，可以作为衰老等退行性疾病的治疗新的药物靶点。