M2-like macrophages derived from THP-1 cells promote myofibroblast differentiation of synovial fibroblasts in association with the TGF-β1/SMAD2/3 signaling pathway
Nguyen Tran Canh Tung, Makiko Nogami, Mami Iwasaki, Yasuhito Yahara, Shoji Seki, Hiroto Makino, Katsuhiko Kamei, Zhongyuan He, Yoshiharu Kawaguchi
Abstract
Fibrosis occurs during progression of osteoarthritis (OA), and myofibroblasts are considered a key effector to drive the fibrotic response. Macrophages also play critical roles in OA progression. However, whether macrophage polarization is involved in OA-related fibrosis has not been adequately defined. Here, we investigated the effect of M2-like macrophages compared to M1-like macrophages on the myofibroblast differentiation of human synovial fibroblasts (HSFs). M1- and M2-like macrophages differentiated from the human monocytic THP-1 cells were co-cultured with HSFs for 72 h. Alpha-smooth muscle actin (α-SMA) positive cells and gene expression of pro-fibrotic and anti-fibrotic factors were quantified. The concentration of transforming growth factor-beta1 (TGF-β1) in the culture supernatant was also analyzed, and its effect on the regulation of the TGF-β/SMAD signaling pathway was further investigated. We found that, cocultured with M2-like macrophages increased the number of α-SMA positive cells and expression of pro-fibrotic genes and decreased the expression of anti-fibrotic genes in HSFs. TGF‑β1 was highly secreted by M2‑like macrophages and accelerated the phosphorylation of SMAD2/3 in HSF cells. Our results indicate the pro-fibrotic effects of M2-like macrophages in myofibroblast differentiation of HSFs, in association with the TGF-β1/SMAD2/3 signaling pathway activation. Thus, M2-like macrophages may play a role in OA fibrogenesis and its progression.