Induction of apoptosis in SSN-1cells by Snakehead Fish Vesiculovirus (SHVV) via Matrix protein dependent intrinsic pathway

Abeer M Hegazy; Nan Chen; Hanzuo Lin; Sarath Babu V; Feng Li; Youcheng Yang; Zhendong Qin; Fei Shi; Jun Li; Li Lin

doi:10.1016/j.fsi.2021.03.010

Induction of apoptosis in SSN-1cells by Snakehead Fish Vesiculovirus (SHVV) via Matrix protein dependent intrinsic pathway

Fish Shellfish Immunol. 2021 Jun:113:24-34. doi: 10.1016/j.fsi.2021.03.010. Epub 2021 Mar 20.

Authors

Abeer M Hegazy¹, Nan Chen², Hanzuo Lin³, Sarath Babu V⁴, Feng Li⁴, Youcheng Yang⁴, Zhendong Qin⁴, Fei Shi⁴, Jun Li⁵, Li Lin⁶

Affiliations

¹ Guangdong Provincial Water Environment and Aquatic Products Security Engineering Technology Research Center, Guangzhou Key Laboratory of Aquatic Animal Diseases and Waterfowl Breeding, College of Animal Sciences and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, Guangdong, 510225, China; Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China; Central Laboratory of Environmental Quality Monitoring (CLEQM), National Water Research Center (NWRC), Cairo, Egypt.
² Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China.
³ Faculty of Science, University of British Columbia, Vancouver, British Columbia, V6T1W9, Canada.
⁴ Guangdong Provincial Water Environment and Aquatic Products Security Engineering Technology Research Center, Guangzhou Key Laboratory of Aquatic Animal Diseases and Waterfowl Breeding, College of Animal Sciences and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, Guangdong, 510225, China.
⁵ Guangdong Provincial Water Environment and Aquatic Products Security Engineering Technology Research Center, Guangzhou Key Laboratory of Aquatic Animal Diseases and Waterfowl Breeding, College of Animal Sciences and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, Guangdong, 510225, China; School of Biological Sciences, Lake Superior State University, Sault Ste. Marie, MI, 49783, USA.
⁶ Guangdong Provincial Water Environment and Aquatic Products Security Engineering Technology Research Center, Guangzhou Key Laboratory of Aquatic Animal Diseases and Waterfowl Breeding, College of Animal Sciences and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, Guangdong, 510225, China. Electronic address: linli@zhku.edu.cn.

PMID: 33757800
DOI: 10.1016/j.fsi.2021.03.010

Abstract

An increasing important area in immunology is the process cell death mechanism, enabling the immune system triggered thru extrinsic or intrinsic signals to effectively remove unwanted or virus infected cells called apoptosis. A recently isolated infectious Snakehead fish vesiculovirus (SHVV), comprising negative strand RNA and encoded viral matrix (M) proteins, is responsible for causing cytopathic effects in infected fish cells. However, the mechanism by which viral M protein mediates apoptosis has not been elucidated. Therefore, in the present experiments, it was investigated the regulatory potential of apoptosis signals during SHVV infection. By employing the model of SHVV infection in SSN-1 cells, the accelerated apoptosis pathway involves an intrinsic pathway requiring the activation of caspase-9 but not caspase-3 or -8. In the groups of infection (SHVV) or treatment (hydrogen peroxide) were induced apoptotic morphological changes and indicated the activation of the main caspases, i.e.; executioner caspase-3, initiators caspase-8 and caspase-9 using colorimetric assays. Turning to the role of viral M protein when it was overexpressed in SSN-1 cells, it was indicated that the viral M gene alone has the ability to induce apoptosis. To elucidate the mechanism of apoptosis in SSN-1 cells, the activation inhibitors of main caspases were used showing that inhibiting of caspase-3 or caspase-8 activation did not seize induction of apoptosis in virus-infected SSN-1 cells. However, the inhibiting of caspase-9 activation reduced significantly the apoptosis initiation process and sharply the expression of viral M gene, suggesting that SHVV plays a major role in the early induction of apoptosis by caspase-9. Interestingly, there were also differences in the mitochondrial membrane potential after the apoptotic induction of caspases, which confirm that caspase-9 is primarily responsible for the cleavage of caspases during apoptosis. Taken together, these findings can therefore be assumed that viral M protein induces apoptosis via the intrinsic apoptotic pathway in SHVV infecting SSN-1 cells.

Keywords: Apoptosis; Caspase; Fish cells (SSN-1); Matrix protein; Snakehead Fish Vesiculovirus (SHVV).

MeSH terms

Animals
Apoptosis*
Cell Line
Fish Diseases / immunology*
Fish Diseases / virology
Fishes*
Rhabdoviridae Infections / immunology
Rhabdoviridae Infections / veterinary*
Rhabdoviridae Infections / virology
Signal Transduction / immunology*
Vesiculovirus / physiology*
Viral Matrix Proteins / physiology*

Substances

Viral Matrix Proteins