SARS-CoV-2 enhances complement-mediated endothelial injury via the suppression of membrane complement regulatory proteins

Complement hyperactivation and thrombotic microangiopathy are closely associated with severe COVID-19. Endothelial dysfunction is a key mechanism underlying thrombotic microangiopathy. To address the relationship between endothelial injury, complement activation and thrombotic microangiopathy of sev...

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Main Authors: Jian Wu, Sanpeng Xu, Zhiqing Li, Boyi Cong, Zongheng Yang, Zhichao Yang, Wanfeng Gao, Shuo Liu, Zhou Yu, Sheng Xu, Nan Li, Jin Hou, Guoping Wang, Xuetao Cao, Shuxun Liu
Format: Article
Language:English
Published: Taylor & Francis Group 2025-12-01
Series:Emerging Microbes and Infections
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Online Access:https://www.tandfonline.com/doi/10.1080/22221751.2025.2467781
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Summary:Complement hyperactivation and thrombotic microangiopathy are closely associated with severe COVID-19. Endothelial dysfunction is a key mechanism underlying thrombotic microangiopathy. To address the relationship between endothelial injury, complement activation and thrombotic microangiopathy of severe COVID-19, we wonder whether, and if so, what and how SARS-CoV-2 factors make endothelial cells (ECs) sensitive to complement-mediated cytotoxicity. We revealed that multiple SARS-CoV-2 proteins enhanced complement-mediated cytotoxicity to ECs by inhibiting membrane complement regulatory proteins (CRPs) and enhancing the deposition of complement-recognizing component FCN1. By screening with CRISPR/Cas9-gRNA libraries, we identified that ADAMTS9, SYAP1, and HIGD1A as intrinsic regulators of CD59 on ECs, which were inhibited by the SARS-CoV-2 M, NSP16, and ORF9b proteins. IFN-γ, GM-CSF, and IFN-α upregulated CD55 and CD59, while IFN-γ antagonized the inhibition of CD59 by the three SARS-CoV-2 proteins. So, the deficiency of IFN-γ weakened the protection of ECs by CRPs against complement-mediated injury which may be enhanced during infection. Our findings illustrated the regulation of protection against complement-mediated attack on self-cells by SARS-CoV-2 infection and immune responses, providing insights into endothelial injury, thrombotic microangiopathy, and potential targets for treating severe COVID-19.
ISSN:2222-1751