P2G 动员联合SDF-1β 趋化内皮祖细胞（EPC）治疗糖尿病后肢缺血的效应和机制

Utilization of endothelial progenitor cells (EPCs) is a promising novel therapeutic option for regeneration of diabetic ischemic tissues. But diabetes reduces EPCs in circulation and abrogates chemokine expression responsible for wound-site EPCs recruitment. Stromal cell derived factor 1 (SDF-1) and its receptor CXCR4 are extensively found to involve in mobilization of bone marrow (BM) EPCs. Antagonizing CXCR4 with a potent antagonist AMD3100 has been shown to induce EPC mobilization and stimulate ischemic angiogenesis, implying that mobilization of EPCs by targeting CXCR4 is a promising strategy for ischemic angiogenesis. ..We recently developed a novel antagonist against CXCR4, SDF-1βP2G (P2G). Our preliminary studies revealed that P2G can effectively improve ischemic angiogenesis and blood reperfusion in both diabetic and non-diabetic mice along with significant EPC mobilization. Based on these novel findings, we HYPOTHESIZE that combined use of P2G to mobilize EPCs from BM into peripheral circulation with ischemia-site administration of SDF-1β to recruit EPCs into ischemic tissue may offer a novel therapy for enhancing diabetic ischemic angiogenesis. To test this hypothesis, we will use a type 2 diabetic mouse hindlimb ischemia model to achieve the following specific aims: Aim 1: To define whether P2G mobilizes EPCs; Aim 2: To determine whether P2G mobilization and SDF-1β recruitment of EPCs enhances ischemic angiogenesis; Aim 3: To define the role of mobilized EPCs in ischemic angiogenesis. This study will verify a novel strategy to combine use of P2G’s systemic mobilization and SDF-1 wound-site recruitment of EPCs for therapy of diabetic vascular diseases.

血管再生障碍是糖尿病缺血性血管疾病的主要发病机理。内皮祖细胞（EPC）在血管再生过程中起关键作用，但糖尿病导致外周EPC数量减少和趋化EPC向创伤部位募集的能力降低。基质细胞衍生因子（SDF-1）及其受体（CXCR4）调节EPC的趋化和迁移，拮抗CXCR4能动员EPC进入外周血，表明以CXCR4为靶点动员自体EPC是一种很有前景的治疗策略。课题组成功研发了一种新颖的CXCR4拮抗剂P2G。预研表明：P2G拮抗CXCR4能有效动员EPC、治疗正常和糖尿病小鼠后肢缺血。据此提出科学假设：P2G动员EPC进入外周血联合损伤部位SDF-1β趋化EPC进入缺血组织能有效治疗糖尿病缺血性血管疾病。本课题的主要目标是系统考察P2G动员联合SDF-1β趋化EPC治疗糖尿病缺血性血管疾病的可行性，并利用多种转基因小鼠模型解析其分子、细胞机制，为将来临床以CXCR4为靶点治疗糖尿病心血管并发症提供科学依据。

本课题的总体目标是系统考察课题组特有专利技术研发而成的CXCR4拮抗剂P2G，探讨以CXCR4为靶点，动员骨髓EPC进入外周血，治疗糖尿病小鼠缺血后肢的血管再生和血流恢复的效应和分子机制，是一个具有广泛临床应用前景的研究领域。课题组紧紧围绕既定研究目标，密切关注国际、国内研究热点，积极跟踪国际前沿，展开卓有成效的合作，创造性的完成了如下研究工作：1）系统解析了P2G动员EPC的剂量效应和时间效应；2）证实P2G动员的EPC具有正常的成血管功能；3）证实单一剂量的P2G动员EPCs相当于单次的EPCs移植，足以达到对db/db糖尿病小鼠HLI的治疗效果，而多剂量的P2G可能因为持续拮抗了EPC表面CXCR4的表达而抑制了EPCs向缺血部位的趋化和迁移，从而抑制其治疗效应；4）P2G能有效促进HFD诱导的糖尿病小鼠后肢缺血后的血流恢复和血管再生； 5）证实P2G 动员和创伤部位 SDF-1 趋化 EPCs 联合协同促进糖尿病后肢缺血的治疗效应；6）证实氧化应激导致糖尿病EPCs的HIF-1α/SDF-1/VEGF信号受损，导致糖尿病EPC功能损伤，抗氧化基因MT高表达能有效保护糖尿病EPC的功能，促进EPC治疗糖尿病缺血性血管疾病的效应；7）证实CXCR4的特异性拮抗剂、CXCR7特异性激动剂TC14012能有效动员骨髓EPC、显著促进糖尿病后肢缺血以后的血流回复和血管再生，再次表明CXCR7确实是糖尿病肢端缺血的重要治疗靶点，特异性激活CXCR7能有效促进糖尿病肢端缺血以后的恢复，TC14012有可能成为治疗糖尿病缺血性血管疾病又一个候选新药。.通过本课题的实施，正式发表SCI研究论文7篇，其中IF>10两篇，累计SCI影响因子49.95，另外还有多篇论文正在投递中；课题组主要成员多次参加国际会议，发表国际会议论文摘要38篇、并做大会发言18次；获得授权发明专利1项；以本课题为载体，培养青年教师3名、博士研究生2名，博士后3名，硕士研究生8名。