Rheumatology and Immuno-mediated Diseases Research Group (IRIDIS), Galicia Sur Health Research Institute (IIS Galicia Sur), SERGAS-UVIGO, Vigo, Spain.
Rheumatology Department, University Hospital Complex of Vigo, Vigo, Spain.
Front Immunol. 2024 Jan 12;14:1268144. doi: 10.3389/fimmu.2023.1268144. eCollection 2023.
Previous works from our group show that Semaphorin3B (Sema3B) is reduced in RA and plays a protective role in a mouse arthritis model. In turn, MerTK plays a protective function in murine arthritis models, is expressed by synovial tissue macrophages and is linked to remission in patients with RA. In this study, we examined the role of Sema3B in the phenotypic characteristics of RA macrophages and the implication of MerTK. Peripheral blood monocytes from RA patients were differentiated into IFN-γ (RA MØ) or M-CSF (RA MØ) macrophages and stimulated with LPS, Sema3B or their combination. Alternatively, RA fibroblast like synoviocytes (FLS) were stimulated with RA MØ and RA MØ supernatants. Gene expression was determined by qPCR and protein expression and activation by flow cytometry, ELISA and western blot. Sema3B down-regulated the expression of pro-inflammatory mediators, in both RA MØ and RA MØ. We observed a similar reduction in RA FLS stimulated with the supernatant of Sema3B-treated RA MØ and RA MØ. Sema3B also modulated cell surface markers in macrophages towards an anti-inflammatory phenotype. Besides, MerTK expression and activation was up-regulated by Sema3B, just as GAS6 expression, Resolvin D1 secretion and the phagocytic activity of macrophages. Importantly, the inhibition of MerTK and neuropilins 1 and 2 abrogated the anti-inflammatory effect of Sema3B. Our data demonstrate that Sema3B modulates the macrophage characteristics in RA, inducing a skewing towards an anti-inflammatory/pro-resolving phenotype in a MerTK-dependant manner. Therefore, here we identify a new mechanism supporting the protective role of Sema3B in RA pathogenesis.
先前我们团队的工作表明，Semaphorin3B（Sema3B）在 RA 中减少，并在小鼠关节炎模型中发挥保护作用。反过来，MerTK 在小鼠关节炎模型中发挥保护作用，由滑膜组织巨噬细胞表达，并与 RA 患者的缓解相关。在这项研究中，我们研究了 Sema3B 在 RA 巨噬细胞表型特征中的作用及其与 MerTK 的关系。从 RA 患者的外周血单核细胞分化为 IFN-γ（RA MØ）或 M-CSF（RA MØ）巨噬细胞，并以 LPS、Sema3B 或其组合刺激。或者，RA 成纤维样滑膜细胞（FLS）用 RA MØ 和 RA MØ 上清液刺激。通过 qPCR 测定基因表达，通过流式细胞术、ELISA 和 Western blot 测定蛋白表达和激活。Sema3B 下调了 RA MØ 和 RA MØ 中促炎介质的表达。我们观察到 RA FLS 受到 Sema3B 处理的 RA MØ 和 RA MØ 上清液刺激时，表达也出现类似的减少。Sema3B 还调节了巨噬细胞表面标志物，使其向抗炎表型转变。此外，Sema3B 上调了 MerTK 的表达和激活，以及 GAS6 的表达、Resolvin D1 的分泌和巨噬细胞的吞噬活性。重要的是，MerTK 和神经纤毛蛋白 1 和 2 的抑制消除了 Sema3B 的抗炎作用。我们的数据表明，Sema3B 调节 RA 中的巨噬细胞特征，以 MerTK 依赖性方式诱导向抗炎/促解决表型倾斜。因此，在这里我们确定了一种新的机制，支持 Sema3B 在 RA 发病机制中的保护作用。
