Synovial macrophages in cartilage destruction and regeneration—lessons learnt from osteoarthritis and synovial chondromatosis

Abstract

Inflammation is a critical process in disease pathogenesis and the restoration of tissue structure and function, for example, in joints such as the knee and temporomandibular. Within the innate immunity process, the body’s first defense response in joints when physical and chemical barriers are breached is the synovial macrophages, the main innate immune effector cells, which are responsible for triggering the initial inflammatory reaction. Macrophage is broadly divided into three phenotypes of resting M0, pro-inflammatory M1-like (referred to below as M1), and anti-inflammatory M2-like (referred to below as M2). The synovial macrophage M1-to-M2 transition can affect the chondrogenic differentiation of mesenchymal stem cells (MSCs) in joints. On the other hand, MSCs can also influence the transition between M1 and M2. Failure of the chondrogenic differentiation of MSCs can result in persistent cartilage destruction leading to osteoarthritis (OA). However, excessive chondrogenic differentiation of MSCs may cause distorted cartilage formation in the synovium, which is evidenced in the case of synovial chondromatosis (SC). This review summarizes the role of macrophage polarization in the process of both cartilage destruction and regeneration, and postulates that the transition of macrophage phenotype in an inflammatory joint environment may play a key role in determining the fate of joint cartilage.

TGF-β1 derived from macrophages contributes to load-induced tendon-bone healing in the murine rotator cuff repair model by promoting chondrogenesis

“… 12 Many studies have shown that M2 macrophages exert a chondro-inductive effect on MSCs and promote cartilage regeneration. 18 , 34 , 35 Unsurprisingly, our study revealed that MS-CM can substantially increase the chondrogenic differentiation of MSCs, in which TGF‐β1 is extremely highly expressed. Further functional assays showed that TGF‐β1 is required for mechanically stimulated macrophage-induced promotion of chondrogenic responses of MSCs.…”

Global Trends and Future Research Directions for Temporomandibular Disorders and Stem Cells

“…The most cited paper (67 citations in WoS-CC, 5,07%) was by Wu et al in 2014, entitled “The pilot study of fibrin with temporomandibular joint derived synovial stem cells in repairing TMJ disc perforation” [ 36 ], and published in the journal “BioMed research international” which deals with a pilot study for the use of scaffold fibrin/chitosan hybrids and mesenchymal stem cells, to evaluate the repair of the TMJ joint disc. Twelve articles received only one citation [ 11 , 18 , 28 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 ]. Ten articles were not cited in Wos-CC [ 27 , 29 , 46 , 47 , 48 , 49 , 50 , 51 , 52 ].…”

Comparison of proteomic landscape of extracellular vesicles in pleural effusions isolated by three strategies

“…Tumor-associated macrophages (TAMs) are activated macrophages associated with tumor progression in various cancers such as lung cancer, breast cancer, and ovarian cancer ( Qiu et al, 2018 ; Nowak and Klink, 2020 ; Song et al, 2020 ; Tan et al, 2021 ). Generally, macrophages are generally classified as M0 (resting macrophages), M1 (classically activated), and M2 (alternately activated) ( Li Y. et al, 2021 ). In our study, M1 markers HLA DR, HLA DP and CD11C were expressed specifically, while M2 markers CD206 were expressed unspecifically.…”