The Studies Of Lead Compounds Targeting Bone Joint Structure With Therapeutic Activity For Osteoarthritis

Background: Osteoarthritis(OA)is a highly disabling,progressive,chronic joint disease.In the early and middle stages of the disease,systemic or local antiinflammatory and analgesic drugs are used for symptomatic treatment,and artificial joint replacement surgery is mainly used for advanced treatment.The OA drug market lacks drugs for the progressive destruction of bone and joint structures,and there is a huge unmet need for clinical treatment.Objective: To explore the pathological mechanism of OA joint tissue damage and remodeling,and to develop new therapeutic drugs that target to improve joint structure and function and relieve joint pain.Methods:(1)The osteoclast differentiation system induced by nuclear factor kappa B receptor activator ligand/macrophage colony-stimulating factor was used to detect the effect of compound YCH2886 on the number of osteoclasts,bone resorption function and structure function of osteoclasts.The effect and related mechanism of YCH2886 on the expression levels of osteoclast differentiation-specific genes and proteins were explored.(2)Toll-like receptor signaling-induced macrophage inflammatory factor secretion system was used to detect the effect of YCH2886 on the secretion levels of proinflammatory cytokines TNF-α,IL-6 and IL-1β.(3)Using IL-1β to stimulate primary mouse cartilage,evaluate the effect of compound YCH2886 on the degree of chondrocyte apoptosis and the expression levels of apoptosis signal-related genes and proteins;To evaluate the effect of compound YCH2886 on the secondary production of pro-inflammatory factors in chondrocytes and the synthetic and catabolic enzyme expression,as well as to explore the protective mechanisms of chondrocytes.(4)The rat OA model was induced by sodium iodoacetate(MIA)to evaluate the relieving effect of YCH2886 on OA joint pain.And the improvement effect and related mechanism of YCH2886 on cartilage and subchondral bone structure damage were explored.Results:(1)The osteoclast formation and bone erosion of osteoclast were significantly inhibited by compound YCH2886.The number of F-actin rings and the expression of osteoclast differentiation-determining genes and proteins were reduced by compound YCH2886.The activation of NF-κB and MEK/ERK-related upstream and downstream molecules in the osteoclast differentiation signaling pathway were also inhibited by compound YCH2886.(2)The level of IL-1β produced by activated macrophages was significantly down-regulated by YCH2886.(3)IL-1β-induced chondrocyte apoptosis rate,chondrocyte pro-apoptotic gene and protein expression levels were significantly decreased by YCH2886.At the same time,the expression levels of anti-apoptotic genes and proteins in chondrocytes and the expression levels of matrix synthase were upregulated by YCH2886.In addition,the production of chondrocyte inflammatory mediators and chondrocyte extracellular matrix degrading enzymes were significantly inhibited by YCH2886.(4)The expression of upstream and downstream signaling molecules of NF-κB and Wnt/β-catenin signaling pathway in chondrocytes was significantly inhibited by YCH2886.(5)The levels of joint pain response and cartilage tissue inflammatory mediators in MIA-induced rat OA model were significantly reduced by local injection of compound YCH2886 into the joint cavity.The superficial fibrillation and proteoglycan loss of the cartilage matrix and the reduction in the number,density and thickness of trabecular bone in the subchondral bone were reversed by YCH2886.In addition,the proportion of hyaline cartilage was up-regulated by YCH2886.The number of subchondral bone osteoclasts,H-type blood vessels and osteophytes were reduced by YCH2886.(6)The expression of pro-apoptotic proteins and the expression of cartilage matrix catabolism enzymes in MIA-induced rat OA model were significantly down-regulated by YCH2886.The expressions of antiapoptotic proteins and cartilage matrix anabolic enzymes were significantly upregulated by YCH2886.The expressions of upstream and downstream related proteins of NF-κB and Wnt/β-catenin signaling pathway in cartilage were down-regulated by YCH2886.Conclusion: The compound YCH2886 had significant osteoclast differentiation inhibitory activity and anti-inflammatory activity after treatment.YCH2886 was able to maintain chondrocyte function and reduce inflammation-induced chondrocyte apoptosis.YCH2886 had the functions of relieving joint pain and improving OA-like structural lesions of cartilage and subchondral bone in MIAinduced rat OA model.YCH2886 exerted chondroprotective effect by blocking the signaling process of NF-κB and Wnt/β-catenin in cartilage tissue.YCH2886 had a good therapeutic effect on experimental OA animal models.The betulinic acid derivative YCH2886 would have the prospect of being developed as a novel OA therapeutic drug that could improve bone structural damage,restore the balance of articular bone remodeling,and improve the microenvironment of the joint cavity.