BMP/Smad信号通路对慢性腱病中肌腱干细胞错误分化的调控作用及其分子机制研究

The pathogenesis of tendinopathy is still largely unknown and treatment is usually symptomatic..Histopathologically, non-tenocyte phenotype cells, tissue metaplasia and failed healing were observed in both clinical and preclinical tendinopathy samples, which is the feature of tendinopathy. In our previous work, we reported the isolation and characterization of tendon stem/progenitor cells (TSPCs) with multi-differentiation potential in human and rat tendon tissues, and we also reported the ectopic expression of osteo-chondrogenic bone morphogenetic proteins (BMPs), such as BMP-2, BMP-4 and BMP-7 in both clinical and preclinical patellar tendinopathy samples, which indicated that these osteo-chondrogenic BMPs might be involved in the pathogenesis of tendinopathy. Recently, we further found that BMP-2 could promote osteogenic differentiation of TSPCs in vitro, which implied that BMP-2 might be one of possible factors regulating the erroneous differentiation of TSPCs in the pathogenesis of tendinopathy..The aims of this project were to compare the multi-differentiation potential (including osteogenic/chondrogenic/adipogenic/tenogenic differentiation potential), proliferative capacity and yield of TSPCs isolated from human or rat healthy patellar tendon and pathological tendon of patellar tendinopathy in vitro and in vivo. The roles of BMP-2 on the multi-differentiation potential of TDSCs were further investigated in vitro and in vivo. The activated state of BMP/Smad signaling pathway (BMPs, BMPRs and Smad 1/5/8) and the osteogenic/chondrogenic/adipogenic/tenogenic differentiation specific gene expression in TSPCs isolated from human or rat healthy patellar tendon and pathological tendon of patellar tendinopathy were also identified and compared quantitatively in vitro and in vivo. Finally, the roles of BMP-2 on the expression of BMP/Smad signaling pathway and these multi-lineage specific genes were also investigated in vitro, as well as the effects of noggin, BMPs antagonist and LDN-193189, BMPR-specific inhibitors on these roles of BMP-2 were verified in vitro. .Our results indicated the role of erroneous differentiation TSPCs in the pathogenesis of tendinopathy, as well as the role and molecular mechanism of BMP/Smad signaling pathway in regulating the erroneous differentiation TSPCs in the pathogenesis of tendinopathy..These findings might provide new insights about the pathogenesis of tendinopathy involving the erroneous differentiation of resident stem cells and BMP/Smad signaling pathway, and also provide some new cues for the establishment of an effective therapeutic strategy for tendinopathy.

慢性腱病病理机制尚未阐明，临床缺乏有效的防治方案。前期研究结果提示：肌腱干细胞（TSPCs）和骨形态蛋白（BMPs）都可能参与其病理过程，导致肌腱中出现非肌腱细胞表型﹑组织化生和肌腱愈合失败。本课题拟在组织、细胞和分子水平比较人﹑大鼠健康和病变髌腱来源TSPCs的数量，增殖能力和多向分化潜能的差异；研究BMP-2对健康TSPCs成骨﹑成软骨﹑成脂和成肌腱功能的调控作用；比较健康和病变髌腱来源TSPCs中BMP/Smad信号通路的活性，研究BMP-2对TSPCs中BMP/Smad信号通路活性及其多向分化特异性基因表达的影响，同时验证其作用是否受noggin或LDN-193189抑制。本课题的顺利实施，将初步阐明TSPCs错误分化在慢性腱病中的作用，以及BMP/Smad信号通路对TSPCs错误分化的调控作用及其分子机制，为慢性腱病的病理机制研究提供新观点，也为临床建立有效的防治策略提供新线索。

慢性腱病病理机制尚未阐明，临床缺乏有效的防治方案。前期研究结果提示：肌腱干细胞（TSPCs）和骨形态蛋白（BMPs）都可能参与其病理过程，导致肌腱中出现非肌腱细胞表型﹑组织化生和肌腱愈合失败。本课题在细胞和分子水平比较健康和病变髌腱来源TSPCs 的数量，增殖能力和多向分化潜能的差异，观察到大鼠慢性腱病来源的TSPCs的数量增加，增殖能力下降，成骨、成软骨和成脂分化能力增加，而成肌腱分化潜能下降；随之研究BMP-2 对健康TSPCs 成骨﹑成软骨﹑成脂和成肌腱功能的调控作用，观察到BMP-2可诱导人和大鼠TSPCs成骨﹑成软骨和成脂分化并抑制成肌腱功能；研究进一步比较健康和病变髌腱来源TSPCs 中BMP/Smad 信号通路的活性差异以及研究BMP-2 对TSPCs 中BMP/BMPR /Smad 信号通路活性表达的影响，观察到BMP/BMPR/Smad信号通路参与了BMP-2对大鼠TSPCs异常分化的调节作用。本课题的顺利实施，初步阐明TSPCs 错误分化在慢性腱病中的作用，以及BMP/Smad信号通路对TSPCs 错误分化的调控作用及其分子机制，为慢性腱病的病理机制研究提供新观点，也为临床建立有效的防治策略提供新线索。