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Wang X, Qiu W, Hu G, Diao X, Li Y, Li Y, Li P, Liu Y, Feng Y, Xue C, Cao Y, Xu Z. NS7a of SADS-CoV promotes viral infection via inducing apoptosis to suppress type III interferon production. J Virol 2024; 98:e0031724. [PMID: 38624231 PMCID: PMC11092342 DOI: 10.1128/jvi.00317-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Accepted: 03/10/2024] [Indexed: 04/17/2024] Open
Abstract
Swine acute diarrhea syndrome coronavirus (SADS-CoV) is a newly discovered swine coronavirus with potential cross-species transmission risk. Although SADS-CoV-induced host cell apoptosis and innate immunity antagonization has been revealed, underlying signaling pathways remain obscure. Here, we demonstrated that infection of SADS-CoV induced apoptosis in vivo and in vitro, and that viral protein NS7a is mainly responsible for SADS-CoV-induced apoptosis in host cells. Furthermore, we found that NS7a interacted with apoptosis-inducing factor mitochondria associated 1 (AIFM1) to activate caspase-3 via caspase-6 in SADS-CoV-infected cells, and enhanced SADS-CoV replication. Importantly, NS7a suppressed poly(I:C)-induced expression of type III interferon (IFN-λ) via activating caspase-3 to cleave interferon regulatory factor 3 (IRF3), and caspase-3 inhibitor protects piglets against SADS-CoV infection in vivo. These findings reveal how SADS-CoV induced apoptosis to inhibit innate immunity and provide a valuable clue to the development of effective drugs for the clinical control of SADS-CoV infection.IMPORTANCEOver the last 20 years, multiple animal-originated coronaviruses, including severe acute respiratory syndrome coronavirus (SARS-CoV), middle east respiratory syndrome coronavirus (MERS-CoV), and SARS-CoV-2, have caused millions of deaths, seriously jeopardized human health, and hindered social development, indicating that the study of animal-originated coronaviruses with potential for cross-species transmission is particularly important. Bat-originated swine acute diarrhea syndrome coronavirus (SADS-CoV), discovered in 2017, can not only cause fatal diarrhea in piglets, but also infect multiple human cells, with a potential risk of cross-species transmission, but its pathogenesis is unclear. In this study, we demonstrated that NS7a of SADS-CoV suppresses IFN-λ production via apoptosis-inducing factor mitochondria associated 1 (AIFM1)-caspase-6-caspase-3-interferon regulatory factor 3 (IRF3) pathway, and caspase-3 inhibitor (Z-DEVD-FMK) can effectively inhibit SADS-CoV replication and protect infected piglets. Our findings in this study contribute to a better understanding of SADS-CoV-host interactions as a part of the coronaviruses pathogenesis and using apoptosis-inhibitor as a drug as potential therapeutic approaches for prevention and control of SADS-CoV infection.
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Affiliation(s)
- Xiaowei Wang
- State Key Laboratory of Biocontrol, School of Life Science, Sun Yat-sen University, Guangzhou, China
| | - Wenjing Qiu
- State Key Laboratory of Biocontrol, School of Life Science, Sun Yat-sen University, Guangzhou, China
| | - Guangli Hu
- State Key Laboratory of Biocontrol, School of Life Science, Sun Yat-sen University, Guangzhou, China
| | - Xiaoyuan Diao
- State Key Laboratory of Biocontrol, School of Life Science, Sun Yat-sen University, Guangzhou, China
| | - Yunfei Li
- State Key Laboratory of Biocontrol, School of Life Science, Sun Yat-sen University, Guangzhou, China
| | - Yue Li
- State Key Laboratory of Biocontrol, School of Life Science, Sun Yat-sen University, Guangzhou, China
| | - Peng Li
- Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, USA
| | - Yufang Liu
- State Key Laboratory of Biocontrol, School of Life Science, Sun Yat-sen University, Guangzhou, China
| | - Yongtong Feng
- State Key Laboratory of Biocontrol, School of Life Science, Sun Yat-sen University, Guangzhou, China
| | - Chunyi Xue
- State Key Laboratory of Biocontrol, School of Life Science, Sun Yat-sen University, Guangzhou, China
| | - Yongchang Cao
- State Key Laboratory of Biocontrol, School of Life Science, Sun Yat-sen University, Guangzhou, China
| | - Zhichao Xu
- State Key Laboratory of Biocontrol, School of Life Science, Sun Yat-sen University, Guangzhou, China
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Huang H, Lei X, Zhao C, Qin Y, Li Y, Zhang X, Li C, Lan T, Zhao B, Sun W, Lu H, Jin N. Porcine deltacoronavirus nsp5 antagonizes type I interferon signaling by cleaving IFIT3. J Virol 2024; 98:e0168223. [PMID: 38289117 PMCID: PMC10878044 DOI: 10.1128/jvi.01682-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 12/21/2023] [Indexed: 02/01/2024] Open
Abstract
Porcine deltacoronavirus (PDCoV) has caused enormous economic losses to the global pig industry. However, the immune escape mechanism of PDCoV remains to be fully clarified. Transcriptomic analysis revealed a high abundance of interferon (IFN)-induced protein with tetratricopeptide repeats 3 (IFIT3) transcripts after PDCoV infection, which initially implied a correlation between IFIT3 and PDCoV. Further studies showed that PDCoV nsp5 could antagonize the host type I interferon signaling pathway by cleaving IFIT3. We demonstrated that PDCoV nsp5 cleaved porcine IFIT3 (pIFIT3) at Gln-406. Similar cleavage of endogenous IFIT3 has also been observed in PDCoV-infected cells. The pIFIT3-Q406A mutant was resistant to nsp5-mediated cleavage and exhibited a greater ability to inhibit PDCoV infection than wild-type pIFIT3. Furthermore, we found that cleavage of IFIT3 is a common characteristic of nsp5 proteins of human coronaviruses, albeit not alphacoronavirus. This finding suggests that the cleavage of IFIT3 is an important mechanism by which PDCoV nsp5 antagonizes IFN signaling. Our study provides new insights into the mechanisms by which PDCoV antagonizes the host innate immune response.IMPORTANCEPorcine deltacoronavirus (PDCoV) is a potential emerging zoonotic pathogen, and studies on the prevalence and pathogenesis of PDCoV are ongoing. The main protease (nsp5) of PDCoV provides an excellent target for antivirals due to its essential and conserved function in the viral replication cycle. Previous studies have revealed that nsp5 of PDCoV antagonizes type I interferon (IFN) production by targeting the interferon-stimulated genes. Here, we provide the first demonstration that nsp5 of PDCoV antagonizes IFN signaling by cleaving IFIT3, which affects the IFN response after PDCoV infection. Our findings reveal that PDCoV nsp5 is an important interferon antagonist and enhance the understanding of immune evasion by deltacoronaviruses.
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Affiliation(s)
- Haixin Huang
- College of Veterinary Medicine, Northwest A&F University, Xianyang, Shaanxi, China
- Institute of Virology, Wenzhou University, Wenzhou, Zhejiang, China
| | - Xiaoxiao Lei
- Institute of Virology, Wenzhou University, Wenzhou, Zhejiang, China
| | - Chenchen Zhao
- Institute of Virology, Wenzhou University, Wenzhou, Zhejiang, China
| | - Yan Qin
- Institute of Virology, Wenzhou University, Wenzhou, Zhejiang, China
| | - Yuying Li
- Institute of Virology, Wenzhou University, Wenzhou, Zhejiang, China
| | - Xinyu Zhang
- Institute of Virology, Wenzhou University, Wenzhou, Zhejiang, China
| | - Chengkai Li
- Institute of Virology, Wenzhou University, Wenzhou, Zhejiang, China
| | - Tian Lan
- Institute of Virology, Wenzhou University, Wenzhou, Zhejiang, China
| | - Baopeng Zhao
- Institute of Virology, Wenzhou University, Wenzhou, Zhejiang, China
| | - Wenchao Sun
- Institute of Virology, Wenzhou University, Wenzhou, Zhejiang, China
| | - Huijun Lu
- Changchun Institute of Veterinary Medicine, Chinese Academy of Agricultural Sciences, Changchun, Jilin, China
| | - Ningyi Jin
- College of Veterinary Medicine, Northwest A&F University, Xianyang, Shaanxi, China
- Changchun Institute of Veterinary Medicine, Chinese Academy of Agricultural Sciences, Changchun, Jilin, China
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