Comprehensive gene expression analysis during chondrogenesis from progenitor cells, ,and application of this technique to tissue repair

关节软骨缺损是骨科医生面临的主要临床问题。探索了自体软骨细胞植入(ACI)，并在全球20,000多名患者中进行了治疗。然而，由于缺乏随机对照试验的有效性证据，ACI的有效性仍然存在争议。目前还没有令人满意的临床技术被广泛接受用于这些损伤的再生修复。我们一直对使用骨髓间充质细胞(BMMC)感兴趣，因为它们具有许多合适的特性，因此该程序可以相对容易地在临床上进行。因此，我们对人膝关节软骨缺损进行了骨髓基质细胞移植。虽然临床效果良好，但修复的组织不是透明软骨，而是纤维软骨。我们认为促进软骨细胞分化不仅在科学上非常重要，而且在临床上也是非常重要的。我们已经报道了重组…较多的人骨形态发生蛋白-2(rhBMP-2)可诱导肌源性间充质细胞分化为软骨细胞，并在扩散腔内形成软骨组织。由于该扩散室系统可以将移植细胞与宿主组织分离，并防止宿主细胞污染(新生血管和免疫系统渗透)，因此我们试图通过基因芯片的基因表达谱来鉴定该系统中调控软骨细胞分化的基因。尽管软骨细胞分化的基因表达谱已有报道，但结合扩散室系统可以更有效地分析软骨细胞的分化。我们在这个软骨形成系统中发现了许多上调的基因。我们选择了20个转录因子，其中10个基因在软骨形成的早期上调，通过RNA干扰(RNAi)抑制一些基因揭示了这些基因与软骨形成的关系。将抑制作用最强的KLF9基因导入未分化间充质细胞，但不能促进其向软骨细胞分化。提示KLF9的发病需要协同因素。较少

Articular cartilage defects are a major clinical problem for orthopaedic surgeons. Autologous chondrocyte implantation (ACI) was explored, and performed in more than 20,000 patients worldwide. However, the effectiveness of ACI remains controversial due to a lack of evidence of efficacy from randomized controlled trials. There is currently no satisfactory clinical technique that is widely accepted for the regenerative repair of these lesions.We have been interested in the use of bone marrow mesenchymal cells (BMMC) because they have a number of suitable properties Therefore, this procedure can be performed clinically with relative ease. Thus, we performed BMMC transplantation in human articular cartilage defects in knee joints. Although the clinical results was good, the repair tissue was not hyaline cartilage, but fibrous cartilage. We thought that promotion of chondrogenic differentiation is very important not only in science but also in clinical practice.We have reported that recombi … More nant human Bmp2 (rhBMP-2) could induce the differentiation of muscle-derived mesenchymal cells into chondrocytes and form cartilage tissue in a diffusion chamber. Since this diffusion chamber system can separate transplanted cells from host tissue and prevent host cell contamination (neovascularization and immune system infiltration), we attempted to identify the genes that regulate chondrocyte differentiation in this system by gene expression profile using GeneChip. Although gene expression profiles of chondrocyte differentiation were reported, the combination with a diffusion chamber system can be more powerful tool for the detailed analysis of the chondrocyte .differentiation. We identified many up-regulated genes in this chondrogenic system. We selected 20 transcriptional factor and within them 10 genes were up-regulated in the early phase of chondrogenesis and the suppression of some genes using RNA interference (RNAi) revealed the association of these genes with chondrogenesis. KLF9, which suppressed most, was transfected into undifferentiated mesenchymal cells, but the chondrogenic differentiation was not promoted. It is suggested that KLF9 needed co-factors. Less