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Xu S, Jin T, Weng J. Endothelial Cells as a Key Cell Type for Innate Immunity: A Focused Review on RIG-I Signaling Pathway. Front Immunol 2022; 13:951614. [PMID: 35865527 PMCID: PMC9294349 DOI: 10.3389/fimmu.2022.951614] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 06/06/2022] [Indexed: 12/25/2022] Open
Abstract
The vascular endothelium consists of a highly heterogeneous monolayer of endothelial cells (ECs) which are the primary target for bacterial and viral infections due to EC’s constant and close contact with the bloodstream. Emerging evidence has shown that ECs are a key cell type for innate immunity. Like macrophages, ECs serve as sentinels when sensing invading pathogens or microbial infection caused by viruses and bacteria. It remains elusive how ECs senses danger signals, transduce the signal and fulfil immune functions. Retinoic acid-inducible gene-I (RIG-I, gene name also known as DDX58) is an important member of RIG-I-like receptor (RLR) family that functions as an important pathogen recognition receptor (PRR) to execute immune surveillance and confer host antiviral response. Recent studies have demonstrated that virus infection, dsRNA, dsDNA, interferons, LPS, and 25-hydroxycholesterol (25-HC) can increase RIG-1 expression in ECs and propagate anti-viral response. Of translational significance, RIG-I activation can be inhibited by Panax notoginseng saponins, endogenous PPARγ ligand 15-PGJ2, tryptanthrin and 2-animopurine. Considering the pivotal role of inflammation and innate immunity in regulating endothelial dysfunction and atherosclerosis, here we provided a concise review of the role of RIG-I in endothelial cell function and highlight future direction to elucidate the potential role of RIG-I in regulating cardiovascular diseases as well as virus infectious disease, including COVID-19. Furthered understanding of RIG-I-mediated signaling pathways is important to control disorders associated with altered immunity and inflammation in ECs.
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Affiliation(s)
- Suowen Xu
- Department of Endocrinology, Institute of Endocrine and Metabolic Diseases, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Clinical Research Hospital of Chinese Academy of Sciences (Hefei), University of Science and Technology of China, Hefei, China
- Laboratory of Metabolics and Cardiovascular Diseases, Institute of Endocrine and Metabolic Diseases, University of Science and Technology of China, Hefei, China
- Biomedical Sciences and Health Laboratory of Anhui Province , University of Science and Technology of China, Hefei, China
- *Correspondence: Suowen Xu, ; Jianping Weng,
| | - Tengchuan Jin
- Laboratory of Structural Immunology, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Jianping Weng
- Department of Endocrinology, Institute of Endocrine and Metabolic Diseases, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Clinical Research Hospital of Chinese Academy of Sciences (Hefei), University of Science and Technology of China, Hefei, China
- Laboratory of Metabolics and Cardiovascular Diseases, Institute of Endocrine and Metabolic Diseases, University of Science and Technology of China, Hefei, China
- Biomedical Sciences and Health Laboratory of Anhui Province , University of Science and Technology of China, Hefei, China
- *Correspondence: Suowen Xu, ; Jianping Weng,
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Impairment of the DeISGylation Activity of Foot-and-Mouth Disease Virus Lpro Causes Attenuation In Vitro and In Vivo. J Virol 2020; 94:JVI.00341-20. [PMID: 32295921 PMCID: PMC7307143 DOI: 10.1128/jvi.00341-20] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 04/08/2020] [Indexed: 01/25/2023] Open
Abstract
Foot-and-mouth disease virus (FMDV) leader proteinase (Lpro) affects several pathways of the host innate immune response. Previous studies in bovine cells demonstrated that deletions (leaderless [LLV]) or point mutations in Lpro result in increased expression of interferon (IFN) and IFN-stimulated genes (ISGs), including, among others, the ubiquitin-like protein modifier ISG15 and the ubiquitin specific peptidase USP18. In addition to its conventional papain-like protease activity, Lpro acts as a deubiquitinase (DUB) and deISGylase. In this study, we identified a conserved residue in Lpro that is involved in its interaction with ISG15. Mutation W105A rendered Escherichia coli-expressed Lpro unable to cleave the synthetic substrate pro-ISG15 while preserving cellular eIF4G cleavage. Interestingly, mutant FMDV W105A was viable. Overexpression of ISG15 and the ISGylation machinery in porcine cells resulted in moderate inhibition of FMDV replication, along with a decrease of the overall state of ISGylation in wild-type (WT)-infected cells. In contrast, reduced deISGylation was observed upon infection with W105A and leaderless virus. Reduction in the levels of deubiquitination was also observed in cells infected with the FMDV LproW105A mutant. Surprisingly, similarly to WT, infection with W105A inhibited IFN/ISG expression despite displaying an attenuated phenotype in vivo in mice. Altogether, our studies indicate that abolishing/reducing the deISGylase/DUB activity of Lpro causes viral attenuation independently of its ability to block the expression of IFN and ISG mRNA. Furthermore, our studies highlight the potential of ISG15 to be developed as a novel biotherapeutic molecule against FMD.IMPORTANCE In this study, we identified an aromatic hydrophobic residue in foot-and-mouth disease virus (FMDV) leader proteinase (Lpro) (W105) that is involved in the interaction with ISG15. Mutation in Lpro W105 (A12-LproW105A) resulted in reduced deISGylation in vitro and in porcine-infected cells. Impaired deISGylase activity correlated with viral attenuation in vitro and in vivo and did not affect the ability of Lpro to block expression of type I interferon (IFN) and other IFN-stimulated genes. Moreover, overexpression of ISG15 resulted in the reduction of FMDV viral titers. Thus, our study highlights the potential use of Lpro mutants with modified deISGylase activity for development of live attenuated vaccine candidates, and ISG15 as a novel biotherapeutic against FMD.
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Zhou Q, Wan M, Wei Q, Song Q, Xiong L, Huo J, Huang J. Expression, Regulation, and Functional Characterization of FST Gene in Porcine Granulosa Cells. Anim Biotechnol 2017; 27:295-302. [PMID: 27565874 DOI: 10.1080/10495398.2016.1184675] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Proliferation, differentiation, and estrogen secretion of granulosa cells are the key factors affecting the estrous after weaning in sows. The objective of this study was to evaluate the expression of Follistatin (FST) in the ovary of Xiushui Hang and Duroc sows at weaning and estrus, the effect of FSH on transcript abundance of FST gene in granulosa cells and the role of FST gene in the weaning to estrus using siRNAs targeted to FST gene. In the present study, expression of the FST mRNA was evaluated by real time PCR. The FST mRNA levels showed a reduction from weaning to the estrus in both Xiushui Hang and Duroc sows, and the mRNA levels in Duroc ovary was higher than in Xiushui Hang sows at the beginning of estrus. Granulosa cells were obtained from the two largest follicles around follicular deviation, FST expression was decreased sharply after treatment with FSH (250 ng/ml). Knockdown of FST by siRNA in porcine granulosa cells significantly increased cell proliferation and estrogen secretion. These results indicate that FST gene is a negative regulator of follicle growth and function during the weaning-estrus interval.
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Affiliation(s)
- QuanYong Zhou
- a Institute of Animal Husbandry and Veterinary, Jiangxi Academy of Agricultural Science , Nanchang , P. R. China
| | - MingChun Wan
- a Institute of Animal Husbandry and Veterinary, Jiangxi Academy of Agricultural Science , Nanchang , P. R. China
| | - QiPeng Wei
- a Institute of Animal Husbandry and Veterinary, Jiangxi Academy of Agricultural Science , Nanchang , P. R. China
| | - QiongLi Song
- a Institute of Animal Husbandry and Veterinary, Jiangxi Academy of Agricultural Science , Nanchang , P. R. China
| | - LiGen Xiong
- a Institute of Animal Husbandry and Veterinary, Jiangxi Academy of Agricultural Science , Nanchang , P. R. China
| | - JunHong Huo
- a Institute of Animal Husbandry and Veterinary, Jiangxi Academy of Agricultural Science , Nanchang , P. R. China
| | - JiangNan Huang
- a Institute of Animal Husbandry and Veterinary, Jiangxi Academy of Agricultural Science , Nanchang , P. R. China
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Yang XQ, Wang L, Li HT, Liu D. Immune responses of porcine airway epithelial cells to poly(I:C), a synthetic analogue of viral double-stranded RNA. CANADIAN JOURNAL OF ANIMAL SCIENCE 2015. [DOI: 10.4141/cjas2013-145] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Yang, X.-q., Wang, L., Li, H.-t. and Liu, D. 2015. Immune responses of porcine airway epithelial cells to poly(I:C), a synthetic analogue of viral double-stranded RNA. Can. J. Anim. Sci. 95: 13–20. Swine respiratory disease (SRD) is one of the most economically important diseases affecting the pig industry. The main infectious agents that cause SRD are viruses, but the molecular pathogenesis of viral SRD has not been extensively studied. Here, using digital gene expression tag profiling, the global transcriptional responses to poly(I:C), a synthetic analogue of viral double-stranded RNA, was analyzed in porcine airway epithelial cells (PAECs). The profiling analysis revealed numerous differentially expressed genes (DEGs), including unknown sequences in the porcine nucleotide databases. Gene ontology enrichment analysis showed that DEGs were mainly enriched in response to stress (GO: 0006950), of which, defense response is one sub-process. Poly(I:C) challenge induced a general inflammation response as indicated by marked upregulation of a variety of pathogen recognition receptors, interferon-stimulated genes, proinflammatory cytokines, and chemokines, together with the significant downregulation of anti-inflammatory molecules. Furthermore, the antiapoptotic pathway was triggered, as demonstrated by the significant suppression of molecules involved in the induction of apoptosis, together with the significant stimulation of putative inhibitor of apoptosis. The results indicate that PAECs initiated defense against poly(I:C) challenge through the inflammation responses, whereas poly(I:C) can utilize antiapoptotic pathway to evade host defense.
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Affiliation(s)
- Xiu-qin Yang
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, China
| | - Liang Wang
- Heilongjiang Academy of Agricultural sciences, Harbin, China
| | - Hai-tao Li
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, China
| | - Di Liu
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, China
- Heilongjiang Academy of Agricultural sciences, Harbin, China
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The vOTU domain of highly-pathogenic porcine reproductive and respiratory syndrome virus displays a differential substrate preference. Virology 2014; 454-455:247-53. [PMID: 24725951 DOI: 10.1016/j.virol.2014.02.026] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 02/06/2014] [Accepted: 02/24/2014] [Indexed: 11/24/2022]
Abstract
Arterivirus genus member Porcine reproductive and respiratory syndrome virus (PRRSV) causes an economically devastating disease, recently exacerbated by the emergence of highly pathogenic strains (HP-PRRSV). Within the nonstructural protein 2 of PRRSV is a deubiquitinating enzyme domain belonging to the viral ovarian tumor (vOTU) protease superfamily. vOTUs, which can greatly vary in their preference for their host ubiquitin (Ub) and Ub-like substrates such as interferon stimulated gene 15 (ISG15), have been implicated as a potential virulence factor. Since various strains of PRRSV have large variations in virulence, the specificity of vOTUs from two PRRSV strains of varying virulence were determined. While both vOTUs showed de-ubiquitinating activity and markedly low deISGylating activity, HP-PRRSV demonstrated a strong preference for lysine 63-linked poly-Ubiquitin, tied to innate immune response regulation. This represents the first report of biochemical activity unique to HP-PRRSV that has implications for a potential increase in immunosuppression and virulence.
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