Work

Inhibition of NETosis via PAD4 alleviated inflammation in giant cell myocarditis

Year: 2023

Type: article

Abstract: Aims: Giant cell myocarditis (GCM) is a rare, often rapidly progressive and potentially fatal, disease caused by T-cell-mediated cardiac inflammation that typically affects young and middle-aged adults. The detailed inflammatory response remained unknown, especially the formation of multinucleate giant cells. Methods and Results: Rats were treated with myosin heavy-chain-α peptides to generate a GCM model. We performed single-cell RNA sequencing analysis of 15,714 Cd45+ cells extracted from hearts from GCM rat model and normal rats. We identified 24 subclusters including macrophages, neutrophils, T cells and so on. The GCM was characteristic with macrophage cluster 1, neutrophil cluster 3, macrophage cluster 2, neutrophil cluster 1 and Th17 cells. Two specific macrophage clusters involved in the GCM have roles in phagocytosis, and NETosis was found to contribute into the process of GCM. Its receptor, Ccdc25, expressed in the macrophage cluster 1 and Th17, suggesting that neutrophils could regulate other immune cells in GCM. Importantly, inhibitor of NETosis, GSK484, could alleviate the inflammation of GCM in vivo. Finally, MPO (a marker of neutrophils) and H3cit (a marker of NETosis) were expressed at higher levels in GCM patients than in DCM patients and healthy controls and neutrophils were part of multinucleated giant cells. IMC analysis revealed that the formation of multinucleate giant cells of GCM. Conclusions: We herein present a comprehensive single-cell landscape of the cardiac immune cells in GCM. In addition, we elucidated the contribution of NETosis to the pathogenesis of GCM, which may serve as a potential therapeutic target in the clinic. Funding Information: This study was supported by Beijing Nova Program (grant no. Z20110006820003), the R&D Program of Beijing Municipal Education commission (grant no. KJZD20191002301), the Fundamental Research Funds for the Central Universities, Innovation Fund for Medical Sciences (grant no. 2016-I2M-1-015) and Natural Science Foundation of China (grant no. 31970649). Conflict of Interests: None declared. Ethical Approval: Animal experiments were approved by the Animal Ethics Committee of Fuwai Hospital and this study also complied with the Declaration of Helsinki. The use of human tissue in the present study was approved by the Human Ethics Committee of Fuwai Hospital, Chinese Academy of Medical Sciences. Written informed consent was obtained from each patient.

Source: iScience

DOI: 10.1016/j.isci.2023.107162