Krüppel-like Factor 5 Causes Cartilage Degradation through Transactivation of Matrix Metalloproteinase 9

Abstract

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 (Krüppel-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.Endochondral ossification is an essential process for skeletal development and growth (1). During the process, chondrocytes undergo proliferation and hypertrophic differentiation. The hypertrophic chondrocytes then secrete a specialized extracellular matrix rich in type X collagen (COL10), 2 which is replaced by bone matrix. The ossification begins with chondrocyte apoptosis, cartilage matrix degradation, calcification, vascular invasion from perichondrium and bone marrow, and deposition of bone matrix by osteoblasts (2). Among these individual steps, previous studies have indicated that degradation of cartilage matrix is particularly crucial (3-6). This step requires proteolytic breakdown by a variety of proteinases, among which members of the matrix metalloproteinase (MMP) family are of special interest due to their ability to cleave collagens and aggrecan, the two principal matrix components of cartilage (7,8). However, little is known about transcriptional regulation of MMPs in the endochondral ossification process.Members of the Krüppel-like factor (KLF) family are important transcription factors that regulate development, cellular dif...

Chondrocytic EphrinB2 promotes cartilage destruction by osteoclasts in endochondral ossification

“…5B). Hypertrophic chondrocytes also promote the destruction of growth plate cartilage by expression of a number of catabolic enzymes, including the matrix metalloproteinases (MMPs) MMP13 (Johansson et al, 1997) and MMP9 (Shinoda et al, 2008;Golovchenko et al, 2013) and the aggrecanases ADAMTS4 and ADAMTS5 (Glasson et al, 2004;Rogerson et al, 2008). We reasoned that, since ephrin B2 deletion was targeted to osteoblasts and chondrocytes, the lack of cartilage destruction in Osx1Cre.…”

“…Hypertrophic chondrocytes also express metalloproteinases and aggrecanases (Johansson et al, 1997;Glasson et al, 2004;Shinoda et al, 2008;Golovchenko et al, 2013) and there are several lines of evidence indicating that these regulate osteoclast activity during endochondral ossification. Mice carrying a collagen mutation rendering it resistant to collagenases show impaired osteoclastic resorption of growth plate cartilage (Chiusaroli et al, 2003), while Mmp13 null mice show impaired osteoclast attachment in endochondral fracture healing (Holliday et al, 1997;Kosaki et al, 2007).…”

KLF5 Activates MicroRNA 200 Transcription To Maintain Epithelial Characteristics and Prevent Induced Epithelial-Mesenchymal Transition in Epithelial Cells

“…KLF5 is a transcription factor, so we predicted that EMT induced by KLF5 knockdown is mediated by key transcriptional targets of KLF5. Several microarray-based studies have identified a large number of protein-coding genes that are transcriptionally regulated by KLF5 (3,(50)(51)(52). Evaluation of these KLF5 target genes did not point to significant regulators of EMT.…”

Krüppel-like factors in mammalian stem cells and development

“…Scale bar: 0.2 amino acid changes per site. (Frontelo et al, 2007;Nuez et al, 1995;Ouyang et al, 1998;Perkins et al, 1995;Siatecka et al, 2007;Zhang et al, 2001b) (Anderson et al, 1995;Basu et al, 2005;Carlson et al, 2006;Kuo et al, 1997a;Kuo et al, 1997b;Lee et al, 2006;Nakagawa et al, 2008;Wang et al, 2013;Wani et al, 1999a,b;Wu et al, 2005;Xie et al, 2011;Zhang et al, 2004 (Chaib et al, 2001;Chen et al, 2002;Chen et al, 2005a;Conkright et al, 1999;Du et al, 2007;Ge et al, 2015;He et al, 2009;Liu et al, 2010;McConnell et al, 2009;McConnell et al, 2007;Nakagawa et al, 2008;Nandan et al, 2010;Nandan et al, 2008;Oishi et al, 2008;Oishi et al, 2005;Qin et al, 2015;Shindo et al, 2002;Shinoda et al, 2008;Takeda et al, 2010;Tong et al, 2006;Wan et al, 2008;...…”