The role of hcs-24, a newly isolated hypertrophic chondrocyte-specific gene, in endochondral ossification

1)克隆了肥大软骨细胞特异性基因hcs-24的c DNA序列。HCS-24编码区与结缔组织生长因子(CTGF)编码区核苷酸序列完全一致。2)在增生期培养的兔软骨细胞中，HCS-24/CTGF表达最高。用转化生长因子β和骨形态发生蛋白-2.3刺激软骨细胞的基因表达)免疫组织化学方法显示，小鼠肋骨软骨交界处肥大的软骨细胞和内皮细胞被抗CTGF抗体染色。4)在小鼠胚胎发育过程中，hcs-24/CTGF的表达水平在胚胎第7天达到最大值，在第17天逐渐下降，然后又升高。…基因对血管内皮细胞增殖和迁移能力的影响6)纯化的CTGF和重组CTGF均能刺激软骨细胞的增殖和蛋白多糖的合成，促进软骨细胞和成骨细胞的碱性磷酸酶的合成。生长因子模拟血管内皮细胞的增殖和迁移。7)建立了检测HCS-24/CTGF的酶联免疫吸附试验体系。8)在HCS-2/8细胞上发现了两种类型的特异性结合位点。(9)转OCNT/CTGF转基因小鼠骨骼结构紊乱，提示肥大软骨细胞合成的HCS-24/CTGF可刺激增殖软骨细胞的增殖成熟和成熟软骨细胞的肥大，诱导软骨细胞血管生成，促进软骨内成骨。该因子也可能参与胚胎的器官发生。较少

1) cDNA of hypertrophic chondrocyte specific gene hcs-24 was isolated. The nucleotide sequence of coding region of hcs-24 was completely the same as that of connective tissue growth factor (CTGF).2) Expression of hcs-24/ctgf in rabbit growth cartilage cells in culture was highest in hypertrophic stage. The gene expression in chondrocytic cells was stimulated by TGFbeta and BMP-2.3) Immunohistochemical techniques revealed that hypertrophic chondrocytes and endothelial cells in cost-chondral junctions of mouse ribs were stained with anti-CTGF antibody in vivo. Surface of and chondrocyte clusters in articular cartilge of arthritis were also stained with the antibody.4) During development of mouse embryos, mRNA level of hcs-24/ctgf reached a maximum at E7, decreased gradually and then increased again at E17.HCS-2/8 cells transfected with an hcs-24 expression vector grew rapidly than non-transfected cells. The abilities to proliferate and migrate of vascular endothelial cells transfected wi … More th expression vectors that generate anti-sense RNA of CTGF cDNA were markedly lower than those of control.6) Purified CTGF and recombinant CTGF stimulated the proliferation and proteoglycan synthesis of chondrocytes and alkaline phosphatase in chondrocytes and osteoblasts. The growth factor simulated the proliferation and migration of vascular endothelial cells. These effects were inhibited by anti-CTGF antibody.7) An ELISA system to measure Hcs-24/CTGF was established.8) Two types of specific binding sites of ^<125>I-rCTGF were identified on HCS-2/8 cells. The binding of ^<125>I-rCTGF to rabbit growth cartilage cells in culture was maximal in growth phase and decreased as they differentiated.9) Transgenic mice of OCNT/CTGF had skeletal disorder.These findings suggest that Hcs-24/CTGF synthesized by hpertrophic chondrocytes stimulates the proliferation and maturation of proliferative chondrocytes and hypertrophy of mature chondrocytes and induces angiogenesis into cartilage from bone, resulting in promotion of endochondral ossification. The factor may also be involved in organogenesis in embryos. Less