Inflammatory response triggered by avian hepatitis E virus in vivo and in vitro

Yawen Zhang; Zengna Chi; Zhizhong Cui; Shuang Chang; Yixin Wang; Peng Zhao

doi:10.3389/fimmu.2023.1161665

Inflammatory response triggered by avian hepatitis E virus in vivo and in vitro

Front Immunol. 2023 Mar 30:14:1161665. doi: 10.3389/fimmu.2023.1161665. eCollection 2023.

Authors

Yawen Zhang^{1

2

3}, Zengna Chi^{1

2

3}, Zhizhong Cui^{1

2

3}, Shuang Chang^{1

2

3}, Yixin Wang^{1

2

3}, Peng Zhao^{1

2

3}

Affiliations

¹ College of Veterinary Medicine, Shandong Agricultural University, Tai'an, Shandong, China.
² Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Tai'an, Shandong, China.
³ Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Shandong Agricultural University, Tai'an, Shandong, China.

Abstract

Hepatitis E virus (HEV) is relevant to public health worldwide, and it affects a variety of animals. Big liver and spleen disease (BLS) and hepatitis-splenomegaly syndrome (HSS) associated with avian HEV (aHEV) were first reported in 1988 and in 1991, respectively. Here, cell culture-adapted aHEV genotype 3 strain, YT-aHEV (YT strain), a typical genotype isolated in China, was used for basic and applied research. We evaluated liver injury during the early stages of infection caused by the YT strain in vivo. Both in vivo and in vitro experimental data demonstrated that viral infection induces innate immunity, with mRNA expression levels of two key inflammatory factors, interleukin-1β (IL-1β) and IL-18, significantly upregulated. The YT strain infection was associated with the activation of Toll-like receptors (TLRs), nuclear factor kappa B (NF-κB), caspase-1, and NOD-like receptors (NLRs) in the liver and primary hepatocellular carcinoma epithelial cells (LMH). Moreover, inhibiting c-Jun N-terminal kinase, extracellular signal-regulated kinase (ERK1 or 2), P38, NF-κB, or caspase-1 activity has different effects on NLRs, and there is a mutual regulatory relationship between these signaling pathways. The results show that SB 203580, U0126, and VX-765 inhibited IL-1β and IL-18 induced by the YT strain, whereas Pyrrolidinedithiocarbamate (PDTC) had no significant effect on the activity of IL-1β and IL-18. Pretreatment of cells with SP600125 had an inhibitory effect on IL-18 but not on IL-1β. The analysis of inhibition results suggests that there is a connection between Mitogen-activated protein kinase (MAPK), NF-κB, and the NLRs signaling pathways. This study explains the relationship between signaling pathway activation (TLRs, NF-κB, MAPK, and NLR-caspase-1) and viral-associated inflammation caused by YT strain infection, which will help to dynamic interaction between aHEV and host innate immunity.

Keywords: Avian hepatitis E virus; cell culture; immune response; inflammation; liver injury.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Carcinoma, Hepatocellular*
Caspases
Hepevirus*
Interleukin-18
Liver Neoplasms*
Mitogen-Activated Protein Kinases / metabolism
NF-kappa B / metabolism
Toll-Like Receptors / metabolism

Substances

NF-kappa B
Interleukin-18
Mitogen-Activated Protein Kinases
Toll-Like Receptors
Caspases

Grants and funding

This study was funded by the Key Research and Development Program of Shandong Province, China (grant number 2022TZXD0019).