Xiaofei Gao1, Yang Song1, Pei Du1, Shuang Yang1, Haobo Cui2, Shuang Lu1, Longyuan Hu1, Limin Liu1, Sujie Jia3, Ming Zhao4. 1. Department of Dermatology, Second Xiangya Hospital, Central South University, Changsha 410011, China; Hunan Key Laboratory of Medical Epigenomics, Second Xiangya Hospital, Central South University, Changsha 410011, China; Research Unit of Key Technologies of Diagnosis and Treatment for Immune-related Skin Diseases, Chinese Academy of Medical Sciences, Changsha 410011, China; Clinical Medical Research Center of Major Skin Diseases and Skin Health of Hunan Province, Changsha 410011, China. 2. Department of Pharmacy, The Third Xiangya Hospital, Central South University, Changsha 410013, China. 3. Hunan Key Laboratory of Medical Epigenomics, Second Xiangya Hospital, Central South University, Changsha 410011, China; Department of Pharmacy, The Third Xiangya Hospital, Central South University, Changsha 410013, China. Electronic address: sujiejia@csu.edu.cn. 4. Department of Dermatology, Second Xiangya Hospital, Central South University, Changsha 410011, China; Hunan Key Laboratory of Medical Epigenomics, Second Xiangya Hospital, Central South University, Changsha 410011, China; Research Unit of Key Technologies of Diagnosis and Treatment for Immune-related Skin Diseases, Chinese Academy of Medical Sciences, Changsha 410011, China; Clinical Medical Research Center of Major Skin Diseases and Skin Health of Hunan Province, Changsha 410011, China. Electronic address: zhaoming307@csu.edu.cn.
Abstract
BACKGROUND: Inhibiting Tfh cell overexpansion prevents autoimmune responses and disease flares in systemic lupus erythematosus (SLE). miR-21 is highly expressed in SLE CD4+ T cells, but whether inhibiting miR-21 can reduce Tfh cell expansion and alleviate the disease progression of lupus is unclear. AIM OF THE STUDY: To address the role and molecular mechanism of miR-21 in regulating Tfh cell expansion and its therapeutic effect on SLE. METHODS: We treated 12-week-old MRL/lpr mice with Antagomir-21, which specifically inhibited miR-21 in vivo. After 12 weeks of treatment, we examined the proportions of Tfh cells and germinal center (GC) B cells and serum levels of autoantibodies and evaluated disease severity by histological scoring and albuminuria. We determined the level of intracellular free iron in CD4+ T cells by PGSK probe and examined the expression of the Fth and Tfrc genes by qPCR. Immunohistochemistry (IHC)was used to assess the 5-hmC level in the draining lymph nodes (dLNs) and spleen. RESULTS AND CONCLUSIONS: Inhibiting miR-21 significantly reduced the expansion of Tfh cells and GC B cells. Furthermore, Antagomir-21 highly improved skin lesions and nephritis in MRL/lpr mice. Inhibiting miR-21 reduced intracellular iron accumulation and DNA hydroxymethylation in T cells. In conclusion, inhibiting miR-21 in vivo improves intracellular iron homeostasis and inhibits Tfh cell overexpansion, contributing to reduced autoimmune responses and the remission of disease symptoms in murine lupus.
BACKGROUND: Inhibiting Tfh cell overexpansion prevents autoimmune responses and disease flares in systemic lupus erythematosus (SLE). miR-21 is highly expressed in SLE CD4+ T cells, but whether inhibiting miR-21 can reduce Tfh cell expansion and alleviate the disease progression of lupus is unclear. AIM OF THE STUDY: To address the role and molecular mechanism of miR-21 in regulating Tfh cell expansion and its therapeutic effect on SLE. METHODS: We treated 12-week-old MRL/lpr mice with Antagomir-21, which specifically inhibited miR-21 in vivo. After 12 weeks of treatment, we examined the proportions of Tfh cells and germinal center (GC) B cells and serum levels of autoantibodies and evaluated disease severity by histological scoring and albuminuria. We determined the level of intracellular free iron in CD4+ T cells by PGSK probe and examined the expression of the Fth and Tfrc genes by qPCR. Immunohistochemistry (IHC)was used to assess the 5-hmC level in the draining lymph nodes (dLNs) and spleen. RESULTS AND CONCLUSIONS: Inhibiting miR-21 significantly reduced the expansion of Tfh cells and GC B cells. Furthermore, Antagomir-21 highly improved skin lesions and nephritis in MRL/lpr mice. Inhibiting miR-21 reduced intracellular iron accumulation and DNA hydroxymethylation in T cells. In conclusion, inhibiting miR-21 in vivo improves intracellular iron homeostasis and inhibits Tfh cell overexpansion, contributing to reduced autoimmune responses and the remission of disease symptoms in murine lupus.