雄激素/受体通过调控内皮细胞延胡索酸代谢介导的EndMT促进创伤性异位骨化的研究

Traumatic heterotopic ossification (HO) is a serious complication of joint injury. Our previous study showed that endothelial cells differentiating into ectopic bone via endothelial-mesenchymal transition (EndMT) process is the main cause of traumatic HO. But the underlying mechanisms are unclear. In our preliminary study, we found that androgen receptor (AR) is highly expressed in the ectopic bone tissue specimens from HO patients, together with co-expression of mesenchymal cell marker Sca-1 and osteocalcin. Besides, our in vitro experiments further confirmed that intracellular levels of fumarate hydratase (FH) and fumarate, one of the metabolic intermediates, can be affected by exogenous androgen regulation. Therefore, we presume that androgen/AR acting on endothelial cells leads to function loss of FH during intracellular glucose metabolism. With the accumulation of fumarate, endothelial cells may differentiate into osteoblasts via EndMT process, which results in formation of traumatic HO. In the present study, we will clarify the role of androgen/AR in the pathogenesis of traumatic HO, and elucidate the mechanisms that whether androgen/AR may regulate the metabolism of fumarate-mediated EndMT process in endothelial cells. This project will provide a novel therapeutic strategy and theoretical basis for traumatic HO.

创伤性异位骨化（HO）是关节损伤的严重并发症，我们以往的研究表明，内皮细胞通过内皮间充质转化（EndMT）过程分化为异位骨是其发病的主要原因，但机制仍不明确。我们的预实验发现，创伤性HO患者骨组织标本高表达雄激素受体（AR），间充质细胞标记Sca-1也与骨钙素共表达；体外实验证实，细胞内延胡索酸水合酶（FH）及其代谢产物延胡索酸的表达可受外源性雄激素药物调控。推测，机体遭受创伤后，雄激素/受体通过作用于内皮细胞，导致细胞糖代谢过程中FH功能缺失并引起延胡索酸大量累积，进而通过EndMT途径分化为成骨细胞，可能是创伤性HO形成的重要原因。本项目拟进一步研究雄激素/受体在创伤性HO发病中的明确作用，及其通过调控内皮细胞延胡索酸代谢进而影响EndMT发生的细胞与分子机制。藉此建立治疗新策略，为创伤性HO提供新的研究思路和临床治疗方案。

对于创伤后引起的异位骨化的治疗仍然是一项重要的临床难题。本项目通过从临床观察和检测的结果入手，以提出雄激素作用在内皮细胞表面的受体AR，从而导致细胞糖代谢过程中FH的表达下调，引起FH的功能缺失，促进细胞内延胡索酸的大量堆积，进而通过EndMT分化为成骨细胞最终导致创伤性HO的发生。在我们的研究中，通过对临床HO患者的异位骨组织标本进行免疫荧光染色，建立异位骨化小鼠模型后以雄激素药物DHT进行处理，以及建立人微血管内皮细胞EndMT的体外诱导体系后以DHT进行处理，经过相关基因转录，蛋白表达，显微CT和组织学检查，分析成骨细胞分化，以及骨组织形成。结果表明，AR受体与成骨标志基因强烈共表达，成骨组织与延胡索酸在DHT处理组有明显相关性并同步增加。在本研究中，我们证明了雄激素/AR增加导致延胡索酸代谢障碍引起了异位骨化的重要机制，为临床治疗提供了新的研究思路和治疗方案。