Mechanisms involved in enhancement of the expression and function of aggrecanases by hyaluronan oligosaccharides

Askew

Journal of Biological Chemistry

et al. 2016

Self Cite

Depletion of the cartilage proteoglycan aggrecan is one of the earliest events that occurs in association with osteoarthritis. This loss is often accompanied by a coordinate loss in another glycosaminoglycan, hyaluronan. Chondrocytes experimentally depleted of cell-associated hyaluronan respond by switching to a pro-catabolic metabolism that includes enhanced production of endogenous inflammatory mediators and increased synthesis of matrix metalloproteinases. Hyaluronan turnover is also increased. Together, such a response provides for possible establishment of a self-perpetuating spiral of events that maintains or prolongs the pro-catabolic state. Chondrocytes or cartilage can also be activated by treatment with pro-inflammatory cytokines and mediators such as IL-1␤, TNF␣, LPS, fibronectin fragments, and hyaluronan oligosaccharides. To determine the mechanism of chondrocyte activation due to hyaluronan loss, a depletion method was required that did not include degrading the hyaluronan. In recent years, several laboratories have used the coumarin derivative, 4-methylumbelliferone, as a potent inhibitor of hyaluronan biosynthesis, due in part to its ability to sequester intracellular UDP-glucuronic acid and inhibition of hyaluronan synthase transcription. However, contrary to our expectation, although 4-methylumbelliferone was indeed an inhibitor of hyaluronan biosynthesis, this depletion did not give rise to an activation of chondrocytes or cartilage. Rather, 4-methylumbelliferone directly and selectively blocked gene products associated with the pro-catabolic metabolic state of chondrocytes and did so through a mechanism preceding and independent of hyaluronan inhibition. These data suggest that 4-methylumbelliferone has additional useful applications to block pro-inflammatory cell activation events but complicates how it is used for defining functions related to hyaluronan.The pronounced loss of aggrecan from articular cartilage is an early critical event associated with osteoarthritis (OA) 2 (1, 2). Aggrecan turnover within the extracellular matrix occurs due to the enhanced activity of endoproteinases such as a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) 4 (3, 4) and 5 (5, 6) as well as other matrix metalloproteinases (MMPs) (7)(8)(9)(10)(11). In addition to aggrecan, a significant loss of hyaluronan (HA) is also observed in human OA cartilage as compared with normal human cartilage (12,13). A marked depletion of HA was also observed in articular cartilage damaged experimentally, such as in the anterior cruciate ligament transection model of OA (14) and a reduced-loading, splint immobilization model (15) in dogs. In our studies, cultured explants of human articular cartilage treated with IL-1␣ displayed a loss of HA within the superficial and upper middle layers of cartilage, the same layers in which aggrecan loss occurred (16). Other studies on cytokine-stimulated cartilage explants suggested that HA is lost from the cartilage (17,18), and other studies revealed that the HA is lost...

Section: Methodsmentioning

confidence: 99%

Section: -Mu Inhibition Of Mmp Production Independent Of Ha Blockmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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4-Methylumbelliferone Diminishes Catabolically Activated Articular Chondrocytes and Cartilage Explants via a Mechanism Independent of Hyaluronan Inhibition

Askew

Journal of Biological Chemistry

et al. 2016

Self Cite

Experimental and Therapeutic Medicine

“…Furthermore, Tajima et al (35) indicated that OPN was involved in multidrug resistance by enhancing the binding of CD44 to HA. Ariyoshi et al (36) demonstrated disruptive changes in chondrocyte-matrix interactions by HA oligosaccharides, which induced matrix degradation and elevated levels of aggrecanase (ADAMTS4 and ADAMTS5) activity via the NF-κB signaling pathway. Yatabe et al (4) observed that HA2700 (2,700 kDa HA) suppressed aggrecan degradation in OA chondrocytes via the downregulation of IL-1α-induced ADAMTS4 expression through the CD44 and intracellular adhesion molecule 1 signaling pathways.…”

Section: Discussionmentioning

confidence: 99%

Effect of osteopontin on the mRNA expression of ADAMTS4 and ADAMTS5 in chondrocytes from patients with knee osteoarthritis

Gao

Zeng

Song

et al. 2015

Abstract. Previous studies have demonstrated that osteopontin (OPN) levels are elevated in the synovial fluid and articular cartilage, and are associated with the severity of knee osteoarthritis (OA). However, the role of OPN in the pathogenesis of OA has yet to be elucidated. The present study aimed to investigate the effects of OPN on the expression of the aggrecanases, a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)4 and ADAMTS5, in human OA chondrocytes, as they serve a key function in aggrecan degradation. Human OA chondrocytes were obtained from the knees of 16 patients with OA, and subsequently cultured in a monolayer. The chondrocytes were divided into three groups, which included the control (no treatment), N-OPN (treated with 100 ng/ml OPN, the normal circulating OPN concentration) and the H-OPN groups (treated with 1 µg/ml OPN, a high OPN concentration). Reverse transcription-quantitative polymerase chain reaction was performed to quantify the relative mRNA expression levels of ADAMTS4, ADAMTS5 and aggrecan in the chondrocytes. The mRNA expression levels of ADAMTS4 were significantly reduced in the N-OPN and H-OPN groups when compared with the control group (P<0.0001). In addition, the mRNA expression levels of ADAMTS4 were lower in the H-OPN group when compared with the N-OPN group (P<0.001). However, no statistically significant difference was observed in the relative mRNA expression levels of ADAMTS5 among the three groups (P>0.05). Furthermore, the mRNA expression levels of aggrecan were higher in the N-OPN and H-OPN groups when compared with the control group (P<0.0001), and a statistically significant difference was observed between the N-OPN and H-OPN groups with regard to the mRNA expression of aggrecan (P<0.0001). These results demonstrated that OPN may exert a protective effect in human OA chondrocytes against aggrecan degradation by suppressing the expression of ADAMTS4. IntroductionOsteoarthritis (OA) is the most common degenerative disorder of the joint, which is characterized by the progressive loss of articular cartilage. This loss is attributed primarily to the proteolysis of certain structural components within the extracellular matrix (ECM), including proteoglycans and collagens (1-3). Aggrecan is a major component of the cartilage-specific proteoglycans. A number of studies have indicated that the aggrecanase-mediated degradation of aggrecan is a crucial factor in the development of OA (4-7). Aggrecanases are members of the A disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) family, which includes ADAMTS1, 4, 5, 8, 9 and 15, that are expressed in the articular cartilage tissues and chondrocytes of numerous animal species, in addition to humans (8). A previous study indicated that ADAMTS4 and ADAMTS5 were responsible for aggrecan degradation in a human model of OA (9).Osteopontin (OPN) is an ECM glycoprotein that is hypothesized to be a potential inflammatory cytokine. OPN, as a biomarker, has been studied in vivo in rats (10), in healthy h...

The proteolytic activity of MT4‐MMP is required for its pro‐angiogenic and pro‐metastatic promoting effects

Host

Paye

Detry

et al. 2012

Intl Journal of Cancer

Membrane-type 4 matrix metalloprotease (MT4-MMP) expression in breast adenocarcinoma stimulates tumor growth and metastatic spreading to the lung. However, whether these pro-tumorigenic and pro-metastatic effects of MT4-MMP are related to a proteolytic action is not yet known. Through site directed mutagenesis MT4-MMP has been inactivated in cancer cells through Glutamic acid 249 substitution by Alanine in the active site. Active MT4-MMP triggered an angiogenic switch at day 7 after tumor implantation and drastically accelerated subcutaneous tumor growth as well as lung colonization in recombination activating gene-1-deficient mice. All these effects were abrogated upon MT4-MMP inactivation. In sharp contrast to most MMPs being primarily of stromal origin, we provide evidence that tumor-derived MT4-MMP, but not host-derived MT4-MMP contributes to angiogenesis. A genetic approach using MT4-MMP-deficient mice revealed that the status of MT4-MMP produced by host cells did not affect the angiogenic response. Despite of this tumor intrinsic feature, to exert its tumor promoting effect, MT4-MMP requires a permissive microenvironment. Indeed, tumor-derived MT4-MMP failed to circumvent the lack of an host angio-promoting factor such as plasminogen activator inhibitor-1. Overall, our study demonstrates the key contribution of MT4-MMP catalytic activity in the tumor compartment, at the interface with host cells. It identifies MT4-MMP as a key intrinsic tumor cell determinant that contributes to the elaboration of a permissive microenvironment for metastatic dissemination.