RE-1元件辅助抑制因子对骨关节炎软骨细胞分化的调控作用

Modulatory effects of CoREST on osteoarthritic chondrocytes differentiation

目的观察RE-1元件辅助抑制因子（CoREST）在骨关节炎（OA）软骨细胞中的差异表达并探讨CoREST对OA软骨细胞分化的调控作用。方法取材接受膝关节表面置换的OA患者和正常对照组软骨并提取软骨细胞总蛋白，以Western blot对比CoREST在OA（n=8）和正常软骨（n=8）细胞中表达水平的差异。培养正常原代软骨细胞，采用针对CoREST设计的敲除siRNACoREST的表达至OA相当水平。应用Realtime聚合酶链反应（PCR）技术监测敲除CoREST前后软骨细胞（n=6）表型基因（I型胶原、Ⅱ型胶原、aggrecan和X型胶原）表达水平的变化。结果CoREST表达水平较正常软骨细胞下降69．5％（P〈0．01）。将正常软骨细胞中的CoREST表达knock—down 64．8％后，软骨细胞终末分化表型基因X型胶原的表达水平升高40．0％（P〈0．05），而正常分化表型Ⅱ型胶原和aggrecan的基因表达水平分别降低71．4％（P〈0．01）和57．6％（P〈0．01）。结论CoREST在OA软骨细胞中表达下降，诱发软骨细胞表型基因表达变化，提示CoREST参与了OA软骨细胞分化的调控。

Objective To compare the differential expression of RE-1 silencing transcription factor （REST） corepressor （CoREST） in normal and osteoarthritic chondrocytes and investigate the role of CoR- EST in regulating osteoarthritic chondrocyte differentiation. Methods Osteoarthritic knee cartilage samples were obtained from patients with osteoarthritis undergoing total knee replacement and normal controls. Chonrocytes were isolated and total protein was extracted for Western blotting analysis to compare the differ- ential expression of CoREST between normal controls （n = 8） and osteoarthritic （n = 8） chondrocytes. Pri- marily cultured normal chondrocytes （ n = 6） were treated with specific siRNA to mimic CoREST repression in osteoarthritis. Realtime polymerase chain reaction （PCR） was used to compare the differential expression of chondrocyte phynotypic genes （collagen I, collagen Ⅱ, collagen X and aggrecan） before and after CoREST knock-down. Results CoREST expression level was down-regulated by 69.5% （P 〈 0. 01 ） in osteoarthritic chondrocytes in contrast to that of normal controls. In response to CoREST knock-down by 64. 8% （P 〈0. 01 ） in the primarily cultured chondrocytes, the gene expression level of the chondrocyte terminal differentiation marker gene, collagen X was up-regulated by 40. 0% （P 〈 0. 05） , whereas the differentiation phenotypic genes, collagen Ⅱ and aggrecan were down-regulated by 71.4% （P 〈 0. 01 ） and 57.6% （P 〈 0. 01 ）, respectively. Conclusion CoREST down-regulation triggered the expression regulation of phenotypic genes towards terminal differentiation, which suggested CoREST is involved in the differentiation status modulation of osteoarthritic chodnrocytes.