Kruppel-like factor 5 causes cartilage degradation through transactivation of matrix metalloproteinase 9
Kruppel-like factor 5 causes cartilage degradation through transactivation of matrix metalloproteinase 9
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DOI：
10.1074/jbc.m709857200
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发表时间：
2008-09-05
影响因子：
4.8
通讯作者：
Kawaguchi, Hiroshi
中科院分区：
文献类型：
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作者：
Shinoda, Yusuke;Ogata, Naoshi;Kawaguchi, Hiroshi
虽然软骨基质的降解被认为是骨骼发育过程中软骨内骨化的限速步骤，但对转录调控知之甚少。本研究探讨了Sp/KLF家族成员KLF 5（Kruppel样因子5）在骨骼发育中的作用。KLF 5在软骨细胞和成骨细胞中表达，而在破骨细胞中不表达。杂合子缺陷型（KLF 5（+/-））小鼠在围产期表现出骨骼生长迟缓。虽然软骨细胞增殖和分化正常，但KLF 5（+/-）小鼠的软骨基质降解受损，导致胚胎肢体中初级骨化中心的软骨与骨的替代延迟，以及新生儿生长板中肥大软骨细胞层的延长。微阵列分析确定MMP 9（基质金属蛋白酶9）作为转录靶点，因为它是强烈上调的软骨细胞系OUMS 27中的KLF 5的腺病毒转染。KLF 5过表达通过刺激MMP 9的启动子活性引起明胶降解，而不影响软骨细胞分化或软骨细胞培养中血管内皮生长因子的表达;然而，在破骨细胞前体中，它既不影响MMP 9的表达，也不影响骨细胞分化。KLF 5功能障碍的遗传异质性缺陷或RNA干扰被证实，导致MMP 9的表达减少，在培养的软骨细胞。MMP 9在KLF 5（+/-）胚胎的肢体中表达降低，这与基质降解、钙化和血管化的抑制相关。我们的结论是，KLF 5通过MMP 9的转录诱导导致软骨基质降解，提供了第一个证据表明，蛋白酶的转录调控有助于软骨内骨化和骨骼发育。
Although degradation of cartilage matrix has been suggested to be a rate-limiting step for endochondral ossification during skeletal development, little is known about the transcriptional regulation. This study investigated the involvement of KLF5 (Kruppel-like factor 5), an Sp/KLF family member, in the skeletal development. KLF5 was expressed in chondrocytes and osteoblasts but not in osteoclasts. The heterozygous deficient (KLF5(+/-)) mice exhibited skeletal growth retardation in the perinatal period. Although chondrocyte proliferation and differentiation were normal, cartilage matrix degradation was impaired in KLF5(+/-) mice, causing delay in replacement of cartilage with bone at the primary ossification center in the embryonic limbs and elongation of hypertrophic chondrocyte layer in the neonatal growth plates. Microarray analyses identified MMP9 (matrix metalloproteinase 9) as a transcriptional target, since it was strongly up-regulated by adenoviral transfection of KLF5 in chondrogenic cell line OUMS27. The KLF5 overexpression caused gelatin degradation by stimulating promoter activity of MMP9 without affecting chondrocyte differentiation or vascular endothelial growth factor expression in the culture of chondrogenic cells; however, in osteoclast precursors, it affected neither MMP9 expression nor osteoclastic differentiation. KLF5 dysfunction by genetic heterodeficiency or RNA interference was confirmed to cause reduction of MMP9 expression in cultured chondrogenic cells. MMP9 expression was decreased in the limbs of KLF5(+/-) embryos, which was correlated with suppression of matrix degradation, calcification, and vascularization. We conclude that KLF5 causes cartilage matrix degradation through transcriptional induction of MMP9, providing the first evidence that transcriptional regulation of a proteinase contributes to endochondral ossification and skeletal development.