Publications (3)10.22 Total impact
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Article: The matrilin-3 VWA1 domain modulates interleukin-6 release from primary human chondrocytes.
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ABSTRACT: OBJECTIVE: We previously demonstrated the ability of matrilin-3 to modulate the gene expression profile of primary human chondrocytes (PHCs) towards a state favoring cartilage catabolism. The structure within matrilin-3 responsible for the induction of these catabolic genes is unknown. Here, we investigated the potential of matrilin-3 (MATN3) and truncated matrilin-3 proteins, in both monomeric and oligomeric form, to stimulate IL-6 release in primary human chondrocytes (PHCs). METHODS: We expressed full-length matrilin-3 oligomers, matrilin-3 VWA (von Willebrand factor A) domain oligomers, matrilin-3 4EGF (epidermal growth factor) domain tetramers, matrilin-3 monomers without oligomerization domains, matrilin-3 VWA domain monomers, and matrilin-3 4EGF monomers. We then incubated PHCs in the absence or presence of full-length matrilin-3 or one of the truncated matrilin-3 proteins and finally determined the release of IL-6 in cell culture supernatants. RESULTS: The addition of full-length matrilin-3 oligomers, matrilin-3 VWA domain oligomers, and, less pronounced, matrilin-3 monomers without oligomerization domains, and matrilin-3 4EGF-oligomers to the cell culture medium led to a significant induction of interleukin-6 in PHCs. DISCUSSION: Based on recombinant expression of different matrilin-3 domains in both monomeric and oligomeric form, this work demonstrated that the VWA1 domain of matrilin-3 is primarily responsible for the induction of IL-6 release and that the oligomerization of the VWA1 domain markedly promotes its activity.Osteoarthritis and Cartilage 03/2013; · 3.90 Impact Factor -
Article: Discoidin domain receptor 2 mediates the collagen II-dependent release of interleukin-6 in primary human chondrocytes.
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ABSTRACT: We deciphered constituent parts of a signal transduction cascade that is initiated by collagen II and results in the release of various pro-inflammatory cytokines, including interleukin-6 (IL-6), in primary human chondrocytes. This cascade represents a feed-forward mechanism whereby cartilage matrix degradation is exacerbated by the mutually inducing effect of released collagen II fragments and pro-inflammatory cytokines. We previously proposed discoidin domain receptor 2 as a central mediator in this event. Since this cascade plays a prominent role in the pathogenesis of osteoarthritis, our study further investigates the hypothesis that discoidin domain receptor 2 is a candidate receptor for collagen II, and that transcription factor NFkappaB, lipid kinase PI3K, and the MAP kinases are constituent parts of this very signal transduction cascade. To accomplish this, we selectively knocked down the molecules of interest in primary human chondrocytes, induced the specified cascade by incubating primary human chondrocytes with collagen II, and observed the outcome, specifically the changes in interleukin-6 release. Knockdown was performed by siRNA-mediated gene silencing in the case of discoidin domain receptor 2 (DDR2) or by using specific inhibitors for the remainder of the molecules. Results indicated that discoidin domain receptor 2 mediates the collagen II-dependent release of interleukin-6 in primary human chondrocytes and that MAP kinases p38, JNK and ERK, as well as transcription factor NFkappaB, are integral components of intracellular collagen II signalling. Given the detrimental role of these molecules in osteoarthritis, our findings provide new targets for more specific therapeutics, which may have fewer side effects than those currently applied.The Journal of Pathology 01/2009; 218(2):241-7. · 6.32 Impact Factor -
Article: Matrilin-3 activates the expression of osteoarthritis-associated genes in primary human chondrocytes
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ABSTRACT: Here, we tested the matrilin-3-dependent induction of osteoarthritis-associated genes in primary human chondrocytes. Matrilin stimulation leads to the induction of MMP1, MMP3, MMP13, COX-2, iNOS, IL-1β, TNFα, IL-6 and IL-8. Furthermore, we show the participation of ADAMTS4 and ADAMTS5 in the in vitro degradation of matrilin-3. We provide evidence for a matrilin-3-dependent feed-forward mechanism of matrix degradation, whereby proteolytically-released matrilin-3 induces pro-inflammatory cytokines as well as ADAMTS4 and -5 indirectly via IL-1β. ADAMTS4 and ADAMTS5, in turn, cleave matrilin-3 and may release more matrilin-3 from the matrix, which could lead to further release of pro-inflammatory cytokines and proteases in cartilage.FEBS Letters.
