RACK1/Src/PFKFB3调控内皮祖细胞糖酵解在新型成骨短肽MY-1促进OP大鼠颅骨缺损区血管再生中的机制研究

骨质疏松症（OP）的内皮细胞糖酵解活性减弱，进而导致血管再生能力降低，是OP骨缺损修复缓慢的重要原因。课题组前期成功设计新型成骨短肽MY-1，发现其可促进OP颅骨缺损区血管再生，但具体机制尚不明确。预实验发现，MY-1作用于内皮祖细胞后，RACK1和Src表达上调，糖酵解关键酶PFKFB3磷酸化水平升高，乳酸分泌增加，细胞成管能力增强；沉默RACK1后，PFKFB3的酪氨酸磷酸化水平降低，乳酸分泌减少。因此提出科学假说：MY-1通过上调RACK1促进Src对PFKFB3的磷酸化，提高内皮祖细胞糖酵解水平，进而促进血管再生。本项目拟通过体内外实验，利用基因敲除、免疫共沉淀等技术手段，明确PFKFB3介导的糖酵解在MY-1促血管再生中的作用，阐明RACK1是Src促进PFKFB3磷酸化的关键分子机制。本研究的顺利进行将有助于揭示MY-1促进血管再生的分子机制，为OP骨缺损区修复提供新的思路。

The decreased ability of angiogenesis caused by low glycolytic activity in endothelial cells is an important reason for the compromised bone repair ability of osteoporosis. Our research group has successfully designed a new osteogenic short peptide MY-1, and found that it promoted vascular regeneration in a critical-sized skull defect in ovariectomized rats, but the relative mechanism remains unclear. Preliminary experiments showed that the expression of RACK1 and Src were up-regulated after the application of MY-1 to EPC, and the phosphorylation level of glycolytic key enzyme PFKFB3 was increased, lactic acid secretion was increased, and the ductulization ability of EPC cells was enhanced. After RACK1 silencing, the tyrosine phosphorylation level of PFKFB3 decreased and lactic acid secretion decreased. Therefore, a scientific hypothesis is proposed: My-1 promotes the phosphorylation of PFKFB3 by Src through up-regulation of RACK1, and improves the glycolysis level of EPCs, thus promoting angiogenesis. This project intends to clarify the role of PFKFB3-mediated glycolysis in MY-1's promotion of angiogenesis through in vivo and in vitro experiments by gene knockout, immunoprecipitation and clarify that RACK1 is the key molecular mechanism of Src's promotion of PFKFB3 phosphorylation. The accomplishment of this study will help to reveal the molecular mechanism of MY-1 promoting angiogenesis and provide a new idea for the repair of OP bone defect area.