Department of Dermatology, Kanazawa University Graduate School of Medical Sciences, Kanazawa 920-8641, Japan.
Department of Plastic Surgery, Kanazawa University Hospital, Kanazawa 920-8641, Japan.
Int J Mol Sci. 2024 Jun 1;25(11):6133. doi: 10.3390/ijms25116133.
The bleomycin-induced scleroderma model is a well-established and dependable method for creating a mouse model of SSc (systemic sclerosis). In the field of skin connective tissue diseases, increasing evidence from clinical and animal experiments suggests that TLRs (Toll-like receptors) play an important role in several diseases. This study aimed to determine the role of TLR7 (Toll-like receptor 7) and TLR9 (Toll-like receptor 9) in the mechanisms of immune abnormalities and fibrosis in SSc. This study used TLR7-KO mice (TLR7-knockout mice with a balb/c background) and TLR9-KO mice (TLR9-knockout mice with a balb/c background) as well as WT mice (wild-type balb/c mice). All three kinds of mice were induced by BLM (bleomycin) in a scleroderma model as the experimental group; meanwhile, WT mice treated with PBS (phosphate-buffered saline) were used as the control group. We analyzed the fibrotic phenotype and the immunological abnormality phenotype of TLR7-deficient and TLR9-deficient mice in the SSc disease model using flow cytometry, RT-PCR (reverse transcription-polymerase chain reaction), a histological examination, and IHC (immunohistochemical staining). In a mouse model of SSc disease, the deletion of TLR7 attenuated skin and lung fibrosis, while the deletion of TLR9 exacerbated skin and lung fibrosis. The deletion of TLR7 resulted in a relative decrease in the infiltration and expression of various pro-inflammatory and fibrotic cells and cytokines in the skin. On the other hand, the deletion of TLR9 resulted in a relative increase in the infiltration and expression of various pro-inflammatory and cytokine-inhibiting cells and cytokines in the skin. Under the influence of pDCs (plasmacytoid dendritic cells), the balances of Beff/Breg (IL-6 + CD19 + B cell/IL-10 + CD19 + B cell), Th17/Treg (IL-17A + CD4 + T cell/Foxp3 + CD25 + CD4 + T cell), M1/M2 (CD86 + macrophage/CD206 + macrophage), and Th1/Th2 (TNFα + CD3 + CD4 + T cell/IL-4 + CD3 + CD4 + T cell) were biased towards the suppression of inflammation and fibrosis as a result of the TLR7 deletion. Comparatively, the balance was biased towards promoting inflammation and fibrosis due to the TLR9 deletion. In the SSc model, TLR7 promoted inflammation and fibrosis progression, while TLR9 played a protective role. These results suggest that TLR7 and TLR9 play opposite roles in triggering SSc to produce immune system abnormalities and skin fibrosis.
博来霉素诱导的硬皮病模型是一种建立良好且可靠的方法，可用于创建系统性硬皮病（SSc）的小鼠模型。在皮肤结缔组织疾病领域，越来越多的临床和动物实验证据表明 TLR（Toll 样受体）在多种疾病中发挥重要作用。本研究旨在确定 TLR7（Toll 样受体 7）和 TLR9（Toll 样受体 9）在 SSc 免疫异常和纤维化机制中的作用。本研究使用 TLR7-KO 小鼠（具有 balb/c 背景的 TLR7 敲除小鼠）和 TLR9-KO 小鼠（具有 balb/c 背景的 TLR9 敲除小鼠）以及 WT 小鼠（野生型 balb/c 小鼠）。所有三种类型的小鼠均在硬皮病模型中通过 BLM（博来霉素）诱导作为实验组；同时，用 PBS（磷酸盐缓冲盐水）处理的 WT 小鼠作为对照组。我们使用流式细胞术、RT-PCR（逆转录-聚合酶链反应）、组织学检查和 IHC（免疫组织化学染色）分析 SSc 疾病模型中 TLR7 缺陷和 TLR9 缺陷小鼠的纤维化表型和免疫异常表型。在 SSc 疾病小鼠模型中，TLR7 的缺失减弱了皮肤和肺纤维化，而 TLR9 的缺失则加剧了皮肤和肺纤维化。TLR7 的缺失导致皮肤中各种促炎和纤维化细胞及其细胞因子的浸润和表达相对减少。另一方面，TLR9 的缺失导致皮肤中各种促炎和细胞因子抑制细胞及其细胞因子的浸润和表达相对增加。在 pDCs（浆细胞样树突状细胞）的影响下，由于 TLR7 的缺失，Beff/Breg（IL-6+CD19+B 细胞/IL-10+CD19+B 细胞）、Th17/Treg（IL-17A+CD4+T 细胞/Foxp3+CD25+CD4+T 细胞）、M1/M2（CD86+巨噬细胞/CD206+巨噬细胞）和 Th1/Th2（TNFα+CD3+CD4+T 细胞/IL-4+CD3+CD4+T 细胞）之间的平衡偏向于抑制炎症和纤维化。相比之下，由于 TLR9 的缺失，平衡偏向于促进炎症和纤维化。在 SSc 模型中，TLR7 促进炎症和纤维化进展，而 TLR9 则发挥保护作用。这些结果表明，TLR7 和 TLR9 在触发 SSc 产生免疫系统异常和皮肤纤维化方面发挥相反的作用。
Zotero 插件
