RANTES/CCL5 Induces Collagen Degradation by Activating MMP-1 and MMP-13 Expression in Human Rheumatoid Arthritis Synovial Fibroblasts

Solomon A Agere,Salahuddin Ahmed,Nahid Akhtar,Jeffery M Watson

doi:10.3389/fimmu.2017.01341

Abstract

Regulated on activation, normal T expressed, and secreted (RANTES)/CC ligand 5 (CCL5) participates in rheumatoid arthritis (RA) pathogenesis by facilitating leukocyte infiltration, however, its other pathological functions are not fully defined in RA. In the present study, we evaluated the effect of RANTES/CCL5 on tissue degrading enzymes matrix metalloproteinase-1 (MMP-1) and MMP-13 expression and its contribution to the progressive joint damage by RA synovial fibroblasts (RASFs). Our results showed that RANTES/CCL5 dose dependently induced MMP-1 and MMP-13 expression in monolayers and three-dimensional (3D) micromass of human RASFs, which correlated with an increase in collagenase activity. This activation by RANTES/CCL5 was observed in RASF, but not in osteoarthritis SFs (OASFs). Evaluation of the signaling events showed that RANTES/CCL5 selectively activated PKCδ, JNK, and ERK proteins to induce MMP expression in human RASFs. Pretreatment with a functional antagonist (Met-RANTES) or heparinase III [an enzyme that selectively digests heparan sulfate proteoglycans (HSPGs)] completely abrogated RANTES/CCL5-induced MMP-1 and MMP-13 expression. Interestingly, the inhibition of RANTES/CCL5 using small-interfering RNA approach reduced the ability of interleukin-1β (IL-1β) to induce MMP-1 and MMP-13 expression, asserting its mediatory role in tissue remodeling. In the inhibitor study, only the selective inhibition of HSPGs or PKCδ, ERK, and JNK markedly inhibited RANTES/CCL5-induced MMP-1 and MMP-13 production. Circular dichroism spectroscopy results demonstrated the degradation of collagen triple-helical structure upon exposure to the conditioned media from RANTES/CCL5 stimulated RASFs, which was reverted by a broad-spectrum MMP inhibitor (GM6001). These findings suggest that RANTES/CCL5 not only upregulates MMP-1 and MMP-13 expression by partly utilizing HSPGs and/or PKCδ-JNK/ERK pathways but also mediates IL-1β-induced MMP-1 and MMP-13 expression.

Highlights

Rheumatoid arthritis (RA) is an autoimmune disease in which activated synovial fibroblasts (SFs) produce chemokines to facilitate infiltration of inflammatory cells [1,2,3,4]
Human RA synovial fibroblasts (RASFs) treated with RANTES/CC ligand 5 (CCL5) (20, 50, and 100 ng/ml) for 24 h showed a significant increase in matrix metalloproteinase-1 (MMP-1) (~2.3-fold) and MMP-13 (~2.1-fold) mRNA expression when compared to the untreated control (Figure 1A)
Our results showed expression levels of CCR1 in RASFs was ~20% lower than NLSFs, there was no significant difference observed in the expression levels of CCR5 (Figure S1 in Supplementary Material)

Summary

Introduction

Rheumatoid arthritis (RA) is an autoimmune disease in which activated synovial fibroblasts (SFs) produce chemokines to facilitate infiltration of inflammatory cells [1,2,3,4]. In response to interleukin-1β (IL-1β) and tumor necrosis factor α (TNF-α), RA synovial fibroblasts (RASFs) release chemokines that bind to their receptors to recruit inflammatory cells at the site of inflammation [8]. Among these chemokines, regulated on activation, normal T expressed and secreted (RANTES)/CC ligand 5 (CCL5) is a potent CC chemokine shown to play an important role in RA pathogenesis [9]; its role beyond chemotactic activity is not well defined in RA. RASFs produce RANTES/CCL5 upon stimulation with TNF-α, IL-1β, or interferon gamma [10]

Methods

Results

Conclusion