CCL7 promotes macrophage polarization and synovitis to exacerbate rheumatoid arthritis

Summary: Chemokine C-C motif ligand 7 (CCL7) is implicated in various immune and inflammatory processes; however, its role in rheumatoid arthritis (RA) remains unclear. In this study, we observed that CCL7 expression was upregulated in synovial M1-polarized macrophages and in the serum of RA mice an...

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Main Authors: Jun Chen, Shuo Shi, Xiaojia Li, Feng Gao, Xu Zhu, Ru Feng, Ke Hu, Yicheng Li, Shuiyuan Chen, Rongkai Zhang, Xiaoshuai Wang, Changhai Ding, Gang Liu, Tianyu Chen, Wenquan Liang
Format: Article
Language:English
Published: Elsevier 2025-04-01
Series:iScience
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Online Access:http://www.sciencedirect.com/science/article/pii/S2589004225004389
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Summary:Summary: Chemokine C-C motif ligand 7 (CCL7) is implicated in various immune and inflammatory processes; however, its role in rheumatoid arthritis (RA) remains unclear. In this study, we observed that CCL7 expression was upregulated in synovial M1-polarized macrophages and in the serum of RA mice and patients. CCL7 was found to promote macrophage polarization toward the M1 phenotype while inhibiting M2 differentiation in vitro. Furthermore, intra-articular injection of recombinant CCL7 protein in mice resulted in enhanced M1 polarization, increased inflammation, and fibrosis within synovial tissues, which exacerbated arthritis-associated pain. These effects were partially mitigated by treatment with a CCL7 neutralizing antibody. Mechanistically, we identified a CCL7 autocrine positive feedback loop that amplifies inflammation via the CCL7-CCR1-JAK2/STAT1 pathway. Collectively, our findings reveal a previously unrecognized CCL7-mediated autocrine inflammatory amplification loop that modulates macrophage polarization and exacerbates RA progression, positioning CCL7 as a potential therapeutic target for RA.
ISSN:2589-0042