Chen Hongzhen, Yang Dapeng, Shi Yirui, Wu Haolin, Zhu Huiming, Jiang Tingting, Liu Shu, Wang Dandan
Department of Rheumatology and Immunology, Nanjing Drum Tower Hospital, Clinical College of Nanjing Drum Tower Hospital, Nanjing University of Chinese Medicine, Nanjing 210023, China.
Department of Rheumatology and Immunology, Nanjing Drum Tower Hospital Clinical College of Xuzhou Medical University, Xuzhou 221004, China.
Cell Immunol. 2025 Feb;408:104914. doi: 10.1016/j.cellimm.2024.104914. Epub 2024 Dec 31.
Dermal and pulmonary fibrosis are the main clinical symptoms of systemic scleroderma (SSc), for which there are no effective therapeutic agents. Tocilizumab is thought to improve the symptoms of fibrosis, but the effect of tocilizumab on dermal fibrosis has not been explored. This study aims to investigate the therapeutic effect of tocilizumab on skin fibrosis by inhibiting CD38 macrophages in the bleomycin-induced SSc mice model.
The 8-week-old BALB/c mice were randomly divided into three groups: control group (PBS group), model group (BLM group), and tocilizumab group (TCZ group). The mRNA expression of VIMENTIN, TIMP1, and COL1A1 was measured by qPCR. Western blot was used to detect the protein expression of α-SMA, TGF-β, and COL1A1 in skin tissues. The expression of CD38 macrophages in the BLM-induced fibrosis mouse model was verified by flow cytometry and immunofluorescence.
In comparison to the PBS control group, mice in the BLM group showed skin fibrosis, edema, thickness, and collagen deposition. The percentage of macrophages in the skin, peripheral blood, and spleen was significantly increased in the BLM group, and the percentage of CD38 macrophages increased in the skin and peripheral blood but decreased in the spleen. After co-cultured with macrophages, L929 fibroblasts differentiated into myofibroblasts, with increased mRNA expression of COL1A1, COL3A, TGF-β, and Fibronectin. Furthermore, after being stimulated by LPS, RAW264.7 cells showed increased expression of IL-6 and CD38. The mRNA levels of COL1A1, COL1A2, COL3A, TGF-β, and Fibronectin in L929 fibroblasts were markedly increased when co-cultured with LPS-stimulated RAW264.7 cells. Tocilizumab treatment reduced dermal thickness and collagen deposition induced by BLM. Furthermore, the percentage of total macrophages and CD38 macrophages in the skin and peripheral blood significantly decreased after tocilizumab treatment.
This study revealed that tocilizumab improved skin fibrosis in the SSc mice model, which was mediated by inhibiting skin and peripheral CD38 macrophages.
皮肤和肺部纤维化是系统性硬化症（SSc）的主要临床症状，目前尚无有效的治疗药物。托珠单抗被认为可改善纤维化症状，但托珠单抗对皮肤纤维化的影响尚未得到研究。本研究旨在通过抑制博来霉素诱导的SSc小鼠模型中的CD38巨噬细胞，探讨托珠单抗对皮肤纤维化的治疗效果。
将8周龄的BALB/c小鼠随机分为三组：对照组（PBS组）、模型组（BLM组）和托珠单抗组（TCZ组）。通过qPCR检测波形蛋白（VIMENTIN）、金属蛋白酶组织抑制因子1（TIMP1）和I型胶原蛋白α1（COL1A1）的mRNA表达。采用蛋白质免疫印迹法检测皮肤组织中α-平滑肌肌动蛋白（α-SMA）、转化生长因子-β（TGF-β）和COL1A1的蛋白表达。通过流式细胞术和免疫荧光法验证博来霉素诱导的纤维化小鼠模型中CD38巨噬细胞的表达。
与PBS对照组相比，BLM组小鼠出现皮肤纤维化、水肿、增厚及胶原沉积。BLM组皮肤、外周血和脾脏中的巨噬细胞百分比显著增加，皮肤和外周血中CD38巨噬细胞百分比增加，而脾脏中则降低。L929成纤维细胞与巨噬细胞共培养后分化为肌成纤维细胞，COL1A1、III型胶原蛋白α1（COL3A）、TGF-β和纤连蛋白的mRNA表达增加。此外，RAW264.7细胞经脂多糖（LPS）刺激后，白细胞介素-6（IL-6）和CD38表达增加。L929成纤维细胞与LPS刺激的RAW264.7细胞共培养时，COL1A1、I型胶原蛋白α2（COL1A2）、COL3A、TGF-β和纤连蛋白的mRNA水平显著增加。托珠单抗治疗可减轻博来霉素诱导的皮肤厚度和胶原沉积。此外，托珠单抗治疗后皮肤和外周血中总巨噬细胞和CD38巨噬细胞的百分比显著降低。
本研究表明，托珠单抗可改善SSc小鼠模型中的皮肤纤维化，其机制是通过抑制皮肤和外周的CD38巨噬细胞实现的。
