Klinger Patricia, Surmann-Schmitt Cordula, Brem Matthias, Swoboda Bernd, Distler Jörg H, Carl Hans-Dieter, von der Mark Klaus, Hennig Friedrich F, Gelse Kolja
Department of Orthopaedic Trauma Surgery, University Erlangen-Nuremberg and University Hospital Erlangen, Erlangen, Germany.
Arthritis Rheum. 2011 Sep;63(9):2721-31. doi: 10.1002/art.30335.
To investigate the effect of chondromodulin 1 on the phenotype of osteochondral progenitor cells in cartilage repair tissue.
Self-complementary adeno-associated virus (AAV) vectors carrying chondromodulin 1 complementary DNA (AAV-Chm-1) were applied to cartilage lesions in the knee joints of miniature pigs that were treated by the microfracture technique. Alternatively, isolated porcine osteochondral progenitor cells were infected with AAV-Chm-1 or with AAV-GFP control vectors ex vivo prior to being transplanted into cartilage lesions in which the subchondral bone plate was left intact. The quality of the repair tissue and the degree of endochondral ossification were assessed by histochemical and immunohistochemical methods. The effects of chondromodulin 1 overexpression were also analyzed by angiogenesis assays and quantitative reverse transcriptase-polymerase chain reaction.
AAV-Chm-1-infected cells efficiently produced chondromodulin 1, which had strong antiangiogenic effects, as verified by the inhibition of tube formation of endothelial cells. Gene expression analyses in vitro revealed the cell cycle inhibitor p21WAF1/Cip1 as one target up-regulated by AAV-Chm-1. Direct application of AAV-Chm-1 vectors into microfractured porcine cartilage lesions stimulated chondrogenic differentiation of ingrowing progenitor cells, but significantly inhibited terminal chondrocyte hypertrophy, the invasion of vessel structures, and excessive endochondral ossification, which were otherwise observed in untreated lesions. Indirect gene transfer, with infection of porcine osteochondral progenitor cells by AAV-Chm-1 ex vivo, also supported chondrogenic differentiation of these transplanted cells. AAV-Chm-1-infected cells maintained a chondrocyte-like phenotype and formed a hyaline-like matrix that was superior to that formed by uninfected or AAV-GFP-infected cells.
Our findings indicate that the antiangiogenic factor chondromodulin 1 stabilizes the chondrocyte phenotype by supporting chondrogenesis but inhibiting chondrocyte hypertrophy and endochondral ossification.
研究软骨调节素1对软骨修复组织中骨软骨祖细胞表型的影响。
将携带软骨调节素1互补DNA的自我互补腺相关病毒（AAV）载体（AAV-Chm-1）应用于经微骨折技术治疗的小型猪膝关节软骨损伤处。或者，将分离的猪骨软骨祖细胞在体外感染AAV-Chm-1或AAV-GFP对照载体，然后移植到保留软骨下骨板完整的软骨损伤处。通过组织化学和免疫组织化学方法评估修复组织的质量和软骨内成骨程度。还通过血管生成测定和定量逆转录聚合酶链反应分析软骨调节素1过表达的影响。
AAV-Chm-1感染的细胞有效产生软骨调节素1，其具有强大的抗血管生成作用，这通过抑制内皮细胞管形成得到证实。体外基因表达分析显示细胞周期抑制剂p21WAF1/Cip1是AAV-Chm-1上调的一个靶点。将AAV-Chm-1载体直接应用于微骨折的猪软骨损伤处可刺激向内生长的祖细胞的软骨形成分化，但显著抑制终末软骨细胞肥大、血管结构的侵入和过度的软骨内成骨，而在未治疗的损伤处则可观察到这些情况。通过体外AAV-Chm-1感染猪骨软骨祖细胞进行间接基因转移，也支持这些移植细胞的软骨形成分化。AAV-Chm-1感染的细胞维持软骨细胞样表型并形成优于未感染或AAV-GFP感染细胞形成的透明样基质。
我们的研究结果表明，抗血管生成因子软骨调节素1通过支持软骨形成但抑制软骨细胞肥大和软骨内成骨来稳定软骨细胞表型。
