TSG-6 - a double-edged sword for osteoarthritis (OA).

Conference Paper

PURPOSE: To explore mechanisms underlying the association of TSG-6 with osteoarthritis (OA) progression. METHODS: TSG-6-mediated heavy chain (HC) transfer (TSG-6 activity) and its association with inflammatory mediators were quantified in knee OA (n=25) synovial fluids (SFs). Paired intact and damaged cartilages from the same individuals (20 tibial and 12 meniscal) were analyzed by qRT-PCR and immunohistochemistry (IHC) for gene and protein expression of TSG-6 and components of Inter-alpha-Inhibitor (IαI) and TSG-6 activity ± spiked in IαI. Primary chondrocyte cultures (n=5) ± IL1β or TNFα were evaluated for gene expression. The effects of TSG-6 activity on cartilage extracellular matrix (ECM) assembly were explored using quantitative hyaluronan (HA)-aggrecan binding assays. RESULTS: TSG-6 activity was significantly associated (R > 0.683, P < 0.0002) with inflammatory mediators including TIMP-1, A2M, MMP3, VEGF, VCAM-1, ICAM-1 and IL-6. Although TSG-6 protein and mRNA were highly expressed in damaged articular and meniscal cartilage and cytokine-treated chondrocytes, there was little or no cartilage expression of components of the IαI complex (containing HC1). By IHC, TSG-6 was present throughout lesioned cartilage but HC1 only at lesioned surfaces. TSG-6 impaired HA-aggrecan assembly, but TSG-6 mediated HA-HC formation reduced this negative effect. CONCLUSIONS: TSG-6 activity is a global inflammatory biomarker in knee OA SF. IαI, supplied from outside cartilage, only penetrates the cartilage surface, restricting TSG-6 activity (HC transfer) to this region. Therefore, unopposed TSG-6 in intermediate and deep regions of OA cartilage could possibly block matrix assembly, leading to futile synthesis and account for increased risk of OA progression.

Full Text

Duke Authors

Cited Authors

  • Chou, C-H; Attarian, DE; Wisniewski, H-G; Band, PA; Kraus, VB

Published Date

  • February 2018

Published In

Volume / Issue

  • 26 / 2

Start / End Page

  • 245 - 254

PubMed ID

  • 29129649

Pubmed Central ID

  • PMC5807166

Electronic International Standard Serial Number (EISSN)

  • 1522-9653

Digital Object Identifier (DOI)

  • 10.1016/j.joca.2017.10.019

Conference Location

  • England