Research Paper Volume 11, Issue 19 pp 8664—8680
Decreased RIPK1 expression in chondrocytes alleviates osteoarthritis via the TRIF/MyD88-RIPK1-TRAF2 negative feedback loop
- 1 Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
- 2 Department of Rehabilitation Medicine, The Third Affiliated Hospital of Southern Medical University, Guangzhou 510000, China
- 3 Department of Orthopedics, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230001, Anhui, P.R. China
- 4 Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA 02115, USA
Received: July 20, 2019 Accepted: September 27, 2019 Published: October 11, 2019
https://doi.org/10.18632/aging.102354How to Cite
Copyright © 2019 Liang et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Abstract
Osteoarthritis (OA) is the most common degenerative joint disease and involves the loss of articular cartilage integrity, formation of articular osteophytes, remodeling of subchondral bone, and synovitis. Knockdown of receptor interacting serine/threonine kinase (RIPK) 1 leads to anti-inflammatory and anti-apoptotic effects. However, the involvement of RIPK1 in the pathogenesis of OA is unclear. Here, we evaluated the effect of RIPK1 on chondrocytes and elaborated the underlying molecular mechanism. Knockdown of RIPK1 protected chondrocytes against inflammation and apoptosis induced by interleukin (IL)-1β in vitro and in vivo. RIPK1 was required for myeloid differentiation primary response 88 (MyD88)- and TIR-domain-containing adapter-inducing interferon b (TRIF)-mediated production of matrix metalloproteinases (MMPs) in OA. Moreover, overexpression of RIPK1 promoted the expression of tumor necrosis factor receptor-associated factor 2 (TRAF2), which blocked the expression and phosphorylation of RIPK1. Upregulation of TRAF2 decreased the expression of TRIF, MyD88, and MMPs in chondrocytes. Furthermore, knockdown of RIPK1 blocked activation of the nuclear factor-κB (NF-κB) and c-Jun N-terminal kinase (JNK) signaling pathways. In summary, knockdown of RIPK1 alleviated OA in a manner mediated by the TRIF/MyD88-RIPK1-TRAF2 negative feedback loop and activation of the NF-κB and JNK signaling pathways.