基于VHL/HIF信号通路探讨羌活地黄汤抑制类风湿关节炎滑膜血管生成及骨破坏机理

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by inflammation of the articular synovium, resulting in chronic pain,loss of function, and disability. This chronic disease requires long term treatment. Disease-modifying antirheumatic drugs are the mainstay of treatment for patients with RA. However, many patients fail to show adequate improvement and often continue to experience flares that necessitate additional treatment. As this is now a severe medical problem in China, any method of treatment that can improve this situation would be more than welcome. In China, patients with RA are often treated with herbal medicine. Traditional Chinese Medicine (TCM) has seen significant advancement against RA, such as in improving patients' clinical findings, inhibiting inflammatory reaction and pain. Qianghuo Dihuang Decoction is the professor Shen Pi-An' experience decoction in the treatment of RA. Although clinical studies have confirmed the efficacy in treatment of RA, the mechanism is not yet clear. Previous studies have shown Qianghuo Dihuang Decoction can inhibit synovial angiogenesis. Recent studies found that Hypoxia Inducible Factor-1α(HIF-1α) is essential for mammalian development and is the principal transcription factor activated by low oxygen tensions. Under hypoxic conditions, HIF-1 and HIF-2 are stabilized and coordinate the cellular response to hypoxia by activating gene expression programs that facilitate oxygen delivery and cellular adaptation to oxygen deprivation. The central components of the HIF signaling pathway are the prolyl hydroxylase enzymes (PHDs); von Hippel-Lindau (VHL); HIF-1; and HIF-2. The PHDs and VHL negatively regulate the pathway under normoxic conditions by cooperatively targeting hypoxia-inducible transcription factors HIF-1 and HIF-2 for proteasomal degradation. Previous findings showed that afer knockout of VHL gene in osteoblasts，the expression of VEGF increased，the rate of new bone formation stepped up，the content of calcium became more,and the trabecular bone volume was promoted,VHL/HIF-1α signal pathway promotes angiogenesis through the stimulation of VEGF expression, which subsequently accelerates osteogenesis. These findings are of significant importance to our understanding of the molecular basis of hypoxia tolerance, in RA. In the present study, the mechanism of Qianghuo Dihuang Decoction inhibit angiogenesis in synovial and bone destruction of rheumatoid arthritis was investigated. Which will provide scientific basis for clinical use of Qianghuo Dihuang Decoction.

类风湿关节炎（RA）滑膜血管生成和局部缺氧环境密切相关。目前研究已证实，HIF-1α是RA组织细胞对缺氧适应的关键调控因子，参与滑膜血管生成，还可对成骨细胞、破骨细胞的功能进行调控，参与骨代谢过程。进而发现在常氧的条件下，HIF-1α与VHL蛋白结合而被E3泛素蛋白连接酶识别，导致HIF-1α降解。推测在RA低氧条件下，HIF-1α通过VHL基因介导的泛素化途径降解减少，从而激活下游低氧相关基因的表达，在RA缺氧信息通路上，VHL/HIF可能起着中枢纽带作用。在前期临床研究已证实羌活地黄汤治疗RA疗效确切，基础研究也表明其能抑制RA滑膜血管生成及骨破坏的基础上，本课题拟以VHL基因敲除小鼠为实验对象，建立胶原性关节炎模型及VHL基因敲除成骨-破骨细胞共培养体系，探讨羌活地黄汤对VHL/HIF信号通路影响，研究其改善RA滑膜血管生成及骨破坏机理，从而为羌活地黄汤的临床应用提供理论依据。

类风湿关节炎（RA）滑膜血管生成和局部缺氧环境密切相关。目前研究已证实，HIF-1α是RA组织细胞对缺氧适应的关键调控因子，参与滑膜血管生成，还可对成骨细胞、破骨细胞的功能进行调控，参与骨代谢过程。进而发现在常氧的条件下，HIF-1α与VHL蛋白结合而被E3泛素蛋白连接酶识别，导致HIF-1α降解。推测在RA低氧条件下，HIF-1α通过VHL基因介导的泛素化途径降解减少，从而激活下游低氧相关基因的表达，在RA缺氧信息通路上，VHL/HIF可能起着中枢纽带作用。本项目通过对上海市名中医沈丕安教授的临床经验方的总结与研究，深入、系统地从VHL/HIF信号转导通路及骨免疫机制，研究其作用机理，通过建立条件性敲除VHL基因小鼠CIA模型，通过现代中医药的实验研究途径，探索了羌活地黄汤缓解类风湿关节炎骨破坏及滑膜血管生成机理及具体作用靶点，将组织形态计量学、细胞分子生物学、基因敲除技术与中医药学有效整合，充分利用多学科交叉渗透的优势，从信息调控分子水平上阐释中医学术理论的科学性，为羌活地黄汤临床运用提供科学依据。通过基础研究，明确羌活地黄汤的作用机理，为名老中医经验方的推广运用奠定基础，也有益于名老中医学术思想的传承与发展。