Regulation of chondrocyte differentiation by ADAMTS-12 metalloproteinase depends on its enzymatic activity

Abstract

ADAMTS-12, a metalloproteinase that belongs to ADAMTS family, is strongly upregulated during chondrogenesis and demonstrates prominent expression in the growth plate chondrocytes. ADAMTS-12 potently inhibits chondrocyte differentiation, as revealed by altered expression of both early and later genes critical for chondrogenesis. In addition, ADAMTS-12-mediated inhibition of chondrogenesis depends on its enzymatic activity, since its point mutant lacking enzymatic activity completely loses this activity. Furthermore, the C-terminal four thrombospondin motifs known to bind COMP substrate is necessary for its full proteolytic activity and inhibition of chondrocyte differentiation. Mechanism studies demonstrate that ADAMTS-12 induces PTHrP, whereas it inhibits IHH during chondrogenesis. Furthermore, PTHrP induces ADAMTS-12 and ADAMTS-12 is hardly detectable in PTHrP-/-growth plate chondrocytes. Importantly, knocking down ADAMTS-12 mRNA levels or blocking ADAMTS-12 activity almost abolishes the PTHrP-mediated inhibition of type X collagen expression. Collectively, these findings demonstrate that ADAMTS-12, a downstream molecule of PTHrP signaling, is a novel regulator of chondrogenesis.

Healthy and Osteoarthritic Synovial Fibroblasts Produce a Disintegrin and Metalloproteinase with Thrombospondin Motifs 4, 5, 7, and 12

“…Western blot of ADAMTS-7 showed a band between 114 and 201 kDa, similar to the active form previously described in a human kidney cell line. 55,56 Regarding ADAMTS-12, we also reported a band between 114 and 201 kDa, equivalent to that previously reported in the same human line, 33 and a smaller band between 74 and 114 kDa that could represent the C-terminal fragment containing the TSP-1 repeats. 57,58 As ADAMTS 7 and 12 are involved in the breakdown of arthritic articular cartilage, 56,59 SFs represent other source of both metalloproteinases that would contribute to the maintenance of the cartilage damage.…”

Higher sensitivity of Adamts12-deficient mice to tumor growth and angiogenesis

“…The new generation of Adamts12-deficient mice provides a suitable tool to give new insights into the in vivo functions of this enzyme, which are presently unknown. In addition, this new transgenic tool paves the way for further investigations on the biological functions of ADAMTS-12 in various pathological conditions in which the enzyme is putatively involved such as asthma (Kurz et al, 2006) and arthritis (Bai et al, 2009).…”

“…Among proteases with putative tumor-suppressive functions are the ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs), MMP-related enzymes characterized by the presence of at least one thrombospondin type I domain (TSP-1) (Cal et al, 2001;Porter et al, 2004Porter et al, , 2005Bai et al, 2009). Their multi-domain structure endows these secreted proteins with various functions including the control of cell proliferation, apoptosis, adhesion and migration Rocks et al, 2008;Bai et al, 2009).…”

“…Their multi-domain structure endows these secreted proteins with various functions including the control of cell proliferation, apoptosis, adhesion and migration Rocks et al, 2008;Bai et al, 2009). It is worth noting that ADAMTS-1 and ADAMTS-8 display antiangiogenic properties (Vazquez et al, 1999;Liu et al, 2006).…”

ADAMTS12 Depletion by Insulin in OUMS-27 Human Chondrosarcoma Cells

“…ADAMTS12, being a member of ADAMTSs family, is secreted from the surface of chondrocytes, it binds to components of ECM, and inhibits differentiation of chondrocytes. 8,35 In the cells that ADAMTS12 is overexpressed; all of the early (collagen II and Sox9) and late (collagen X) chondrogenic markers are repressed. 35 31 Oligomeric matrix protein is one of the non-collagenous components of the cartilage tissue and contributes to stabilization of cartilage ECM due to its interaction with collagen types II and IX, aggrecan, and fibronectin.…”