Disease relevance of ADAMTS4

• In transfected human chondrosarcoma cells, this process is not autoproteolytic because the same products form with an inactive mutant of ADAMTS4 (a disintegrin and metalloproteinase with thrombospondin-like motif 4) and truncation is completely blocked by tissue inhibitor of metalloproteinase-1 [1].
• Conversely, ADAMTS4, 6, 14, and 20 are consistently up-regulated in breast carcinomas (P = 0.005, P < 0.0001, P = 0.003, and P = 0.001, respectively) [2].
• Our results show that ADAMTS4 and 5 are upregulated on proliferating glioblastoma cells and these proteases may contribute to their invasive potential [3].
• It is thought that ADAMTS4 plays a pivotal role in inflammatory joint diseases and cartilage degradation [4].
• Role of aggrecanase 1 in Lyme arthritis [5].

High impact information on ADAMTS4

• Our results are consistent with the presence in both normal and arthritic joint cartilage of proteolytic activity against aggrecan based on both classical MMPs and "aggrecanase."[6]
• Aggrecan degradation in human cartilage. Evidence for both matrix metalloproteinase and aggrecanase activity in normal, osteoarthritic, and rheumatoid joints [6].
• To examine the activity of matrix metalloproteinases (MMPs) and aggrecanase in control and diseased human articular cartilage, metabolic fragments of aggrecan were detected with monospecific antipeptide antibodies [6].
• The aggrecanase members of the ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) family cleave a variety of proteins but do not seem to possess distinct sequence specificities [7].
• In the present study, the topological substrate specificity of ADAMTS-4 (aggrecanase-1) was examined using triple-helical or single-stranded poly(Pro) II helical peptides [7].

Chemical compound and disease context of ADAMTS4

• Kinetic analysis of the products present in rat chondrosarcoma cell cultures treated with interleukin-1b showed that the first aggrecanase-mediated cleavages occurred at the four sites within the CS attachment region to generate two stable intermediates, Val(1)-Glu(1459) and Val(1)-Glu(1274) [8].
• Studies in vitro with retinoic acid-stimulated rat chondrosarcoma cells indicated that the rAgg1mut substrate was cleaved at the 'aggrecanase' site equivalent to Glu373-Ala374 (human aggrecan sequence enumeration) in its interglobular domain sequence segment [9].

Biological context of ADAMTS4

• To clone molecules that bind to ADAMTS4, we screened a human chondrocyte cDNA library by the yeast two-hybrid system using the ADAMTS4 spacer domain as bait and obtained cDNA clones derived from fibronectin [10].
• In this study, by using both furin-specific inhibitor and RNA interference technique, we demonstrate that furin plays an important role in the intracellular removal of ADAMTS4 prodomain [11].
• To elucidate the mechanisms of regulation of ADAMTS4 gene expression, we cloned the 5'-flanking region of the human ADAMTS4 gene and characterized its promoter activity by means of reporter assay using porcine chondrocytes and NIH3T3 cells [4].
• In this study we have characterized the substrate specificity of ADAM-TS5 and compared it with that of ADAM-TS4 [12].
• For higher sensitivity of the assay, P1-P5 residues of the aggrecanase site within the aggrecan substrate were changed by in vitro mutagenesis [13].

Anatomical context of ADAMTS4

• Indeed, ADAMTS4 is co-localized with furin in trans-Golgi network [11].
• To examine the mode of activation of ADAMTS4, a human chondrosarcoma cell line, JJ012, has been stably transfected with the full-length c-DNA for human ADAMTS4 [14].
• With ADAMTS4 and hADAMTS1/METH-1 we further extended the set of matrix metalloproteases expressed and regulated by endothelial cells [15].
• CONCLUSION: Coincident with aggrecanolysis, aggrecanase activities in articular cartilage may actuate the release of HA and associated hyaladherins, thereby further compromising the integrity of the cartilage matrix during degenerative joint diseases such as osteoarthritis [16].
• The active forms of ADAMTS-4 were increased in synovial fluid samples from patients with active Lyme arthritis and were elevated in the joints of mice infected with B burgdorferi [5].

Associations of ADAMTS4 with chemical compounds

• In the present study, we further examined the susceptibility of the VEGF(165).CTGF complex to matrix metalloproteinases (MMP-1, -2, -3, -7, -9, and -13), ADAMTS4 (aggrecanase-1), and serine proteinases, and evaluated the recovery of the angiogenic activity of VEGF(165) after the treatment [17].
• ADAMTS-5 was expressed constitutively in synovium with little or no transcriptional regulation by recombinant human interleukin-1 alpha or all-trans-retinoate, factors previously shown to upregulate aggrecanase activity in cartilage [18].
• Further deletion of the cysteine-rich domain reduced the aggrecanase activity by 80% but did not alter the activity against Cm-Tf or fibromodulin [19].
• Antioxidants and activating protein-1 transcription factor inhibitors, nordihydroguaiaretic acid and N-acetyl-L-cysteine (NAC) suppressed MMP and ADAM-TS4 genes [20].
• RESULTS: Both aggrecanase-1 and aggrecanase-2 are able to cleave bovine and human biglycan at a site within their central leucine-rich repeat regions [21].
• Although the spacer domain was critical for ADAMTS-4 localization in the matrix, the cysteine-rich domain influenced ADAMTS-5 localization [22].
• This discrepancy is most likely due to selective inhibition of full-length ADAMTS-4 by heparin, particularly for cleavage at the Glu373-Ala374 bond [23].

Physical interactions of ADAMTS4

• Other TSR-1 domain-bearing truncated ADAMTS constructs demonstrating either positive GAG-binding ability (trADAMTS-9F649) or negligible GAG-affinity (trADAMTS-16F647 and trADAMTS-18F650) displayed comparably low aggrecanase activities [24].
• Proprotein convertase furin interacts with and cleaves pro-ADAMTS4 (Aggrecanase-1) in the trans-Golgi network [11].
• Efficient aggrecanase activity requires the presence of sulfated glycosaminoglycans (GAGs) attached to the aggrecan core protein, implying the contribution of substrate recognition/binding site(s) to ADAMTS-4 activity [25].
• Full-length ADAMTS-4 binds to pericellular and extracellular matrix, but deletion of the spacer domain releases the enzyme [19].

Enzymatic interactions of ADAMTS4

• ADAMTS4 cleaves at the aggrecanase site (Glu373-Ala374) and secondarily at the matrix metalloproteinase site (Asn341-Phe342) in the aggrecan interglobular domain [26].
• It was further demonstrated that purified COMP was cleaved by ADAMTS-4, but not ADAMTS-1 or -5, to yield a fragment which co-migrated with Fragment-110 [27].
• Time course studies indicated that only following depletion of substrate containing the preferred clip site did MMP-8 rapidly cleave at the aggrecanase site [28].
• When tested, recombinant ADAMTS-4 effectively cleaved intact matrilin-3 at the predicted motif at Glu435/Ala436 generating two species of 45 and 5 kDa [29].

Regulatory relationships of ADAMTS4

• The C-terminal 40-kDa fibronectin fragment also inhibited the activity of wild-type ADAMTS4 (IC(50) = 170 nm) [10].
• IL4 down regulated ADAMTS-4 mRNA, whereas TGFbeta1 increased this expression in both bovine and human chondrocytes [30].
• The aggrecanase-1 gene was constitutively expressed by both RA and OA FLS [31].
• Both TGFbeta1 and IL4 blocked membrane associated aggrecanase activity and decreased OSM+TNFalpha-induced expression of ADAMTS-9 in bovine and human chondrocytes [30].
• ADAMTS4 expression was suppressed by both PPAR gamma and RXR agonists and was undetectable when the agonists were combined [32].

Other interactions of ADAMTS4

• The fold increase for ADAMTS9 mRNA was greater than that for mRNA of the other aggrecanase genes [33].
• CONCLUSIONS: OSM+TNFalpha up regulates membrane associated aggrecanase activity and several ADAMTS aggrecanase mRNAs in chondrocytes [30].
• We show here, in digests with native human aggrecan, that purified ADAMTS4 cleaves primarily at the Glu(373)-Ala(374) site, but also, albeit slowly and secondarily, at the Asn(341)-Phe(342) site [26].
• Real-time PCR demonstrated that TGF-beta significantly increased aggrecanase-1 gene expression in FLS [31].
• In addition, our evidence suggests that a furin-independent pathway may also contribute to the activation of ADAMTS4 [11].

Analytical, diagnostic and therapeutic context of ADAMTS4

• Using a variety of protease inhibitors, reverse transcriptase-polymerase chain reaction, and specific antibodies, we determined that this activity is likely to be a member of the ADAMTS family of metalloproteinases, specifically ADAMTS4 [34].
• METHODS: Aggrecanase activity and ability of agents to prevent membrane associated aggrecanase activity were assessed by Western blotting [30].
• The purified protein had aggrecanase activity and appears as two major bands on the silver stained SDS-PAGE corresponding well to a pro-domain on form of 115 kDa and a pro-domain off form of 90 kDa [35].
• Recombinant aggrecanase-1 and alpha1-antitrypsin were expressed in mammalian cells and used in co-immunoprecipitation experiments, which showed that full-length aggrecanase-1 and alpha1-antitrypsin are also associated in vivo [36].
• Utilization of a recombinant substrate rAgg1 to study the biochemical properties of aggrecanase in cell culture systems [37].

References