OLA1在血管生成中的作用及VEGFA/OLA1/AKT1轴的调控机制研究

血管生成受到精确调控，一旦异常会引起多种疾病发生，靶向血管生成已成为肿瘤及眼科疾病的重要治疗策略。但对于血管生成是如何实现精确调控的，还未能完全理解。我们发现一个新蛋白OLA1在血管瘤病人组织中表达显著下调，于是建立了内皮细胞特异性OLA1敲除小鼠，发现OLA1抑制小鼠视网膜血管生成及角膜和基质胶中血管生成。体外实验支持OLA1负调控AKT1抑制血管生成，且VEGFA下调OLA1表达。因此，本课题提出在内皮细胞中，OLA1通过抑制ATK1的功能，维持机体适度的血管生成。我们将进一步研究1）OLA1在生理性视网膜血管生成和病理性血管生成中的作用；2）OLA1是如何调控血管内皮细胞功能的；3）OLA1调控AKT1及VEGFA下调OLA1的机制。本课题率先建立内皮细胞特异性OLA1敲除小鼠，将从分子水平阐明OLA1限制过度血管生成的机制，为理解血管生成的精密调控及相关疾病的发生治疗提供理论依据。

Angiogenesis is a fine-regulated process of vasculature formation from the pre-existing blood vessels, which has been implicated in several major diseases, such as cardiovascular disease, stroke, cancer and inflammatory diseases. Targeting the angiogenesis has been beneficial for treatment of cancer and eye diseases in clinic. The process of angiogenesis involves several stages and is strictly controlled. Therefore, study on new molecules involved in angiogenesis may provide novel avenues for improving the therapy of related diseases. Our recent evidence suggests that OLA1 (Obg like ATPase 1)，named in 2007, may play a vital role in angiogenesis. By studying human hemangiomas tissues, we found that the expression of OLA1 is largely decreased in both adult hemangioma and infantile hemangioma. Also, OLA1 expression is dramatically reduced in hemangioma cells HemECs, compared that in HUVECs. These results indicate that OLA1 might has a role in angiogenesis. Then, we generated endothelial OLA1 specific knockout mice (TEK-Cre;OLA1flox/flox: OLA1ECKO), which are viable and fertile, and found that conditional loss of OLA1 in endothelial cells enhances murine retinal angiogenesis. The observed promoted angiogenesis is also confirmed in the corneal micropocket and Matrigel plug models. In HUVECs, OLA1 knockdown boosts in vitro angiogenesis and upregulates the expression of AKT1. Since the reverse phase protein array (RPPA) also shows that both the expression of AKT and p-AKT are increased in OLA1 knockout endothelial cells, compared that in wild-type cells, and both database and our results show that VEGFA treatment could downregulate the mRNA expression of OLA1, we therefore hypothesize that OLA1 inhibits angiogenesis by downregulating AKT1 signaling and OLA1 plays an important role in maintain the proper angiogenesis. Herein, my specific aims are: (1) To further determine the function of OLA1 in physiological and pathological angiogenesis; (2) To determine the role of OLA1 in endothelial cells; (3) To determine the mechanisms about how OLA1 prohibits AKT1 signaling and how VEGFA downregulates OLA1. Our study will reveal the function of OLA1 in endothelial cells and angiogenesis. This study will also provide a proof-of-principle to the mechanism by which OLA1 controls angiogenesis and will help guide the design of therapy on its related diseases.