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Wang L, Li Y, Liu Y, Zuo L, Li Y, Wu S, Huang R. Salmonella spv locus affects type I interferon response and the chemotaxis of neutrophils via suppressing autophagy. Fish Shellfish Immunol 2019; 87:721-729. [PMID: 30753916 DOI: 10.1016/j.fsi.2019.02.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 02/02/2019] [Accepted: 02/08/2019] [Indexed: 06/09/2023]
Abstract
Salmonella is a facultative intracellular pathogen that can cause significant morbidity and mortality in humans and animals. Salmonella plasmid virulence (spv) gene sequence is a highly conserved 6.8 kb region which exists in the plasmid of most pathogenic Salmonella. Autophagy is a degradation process of unnecessary and dysfunctional cytoplasm components to maintain cellular homeostasis, which could affect host inflammatory responses, such as type I interferon response. Type I interferon response can promote the antibacterial activity of macrophage as well as the secretion of cytokines and neutrophil chemokines. We previously reported that spv locus could suppress autophagy and the aggregation of neutrophils in zebrafish larvae. To explore the influence of spv locus on Salmonella escaping from the innate immune responses and the underlying mechanism, the models of Salmonella enterica serovar Typhimurium infected macrophages in vitro and zebrafish larvae in vivo were used in this study. The interactions among spv locus, autophagy, type I interferon response and the chemotaxis of neutrophils were investigated. Western blot was used to detect the expression levels of autophagy related proteins and RT-qPCR was used to measure the mRNA levels of type I interferon response and the neutrophil chemokines. The chemotaxis of neutrophils were observed by Laser Scanning confocal microscopy. Autophagy agonist Torin 1 was also involved to interfere the autophagy influx. Results showed that spv locus could restrain type I interferon response and the chemotaxis of neutrophils via suppressing autophagy, which provided substantial foundation to study the mechanism of Salmonella escaping the innate immunity.
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Affiliation(s)
- Lidan Wang
- Department of Microbiology, Medical College of Soochow University. No. 199, Ren Ai Road, Suzhou, Jiangsu, 215123, PR China
| | - Yangli Li
- Department of Microbiology, Medical College of Soochow University. No. 199, Ren Ai Road, Suzhou, Jiangsu, 215123, PR China
| | - Yuanhui Liu
- Department of Microbiology, Medical College of Soochow University. No. 199, Ren Ai Road, Suzhou, Jiangsu, 215123, PR China
| | - Lingli Zuo
- Department of Microbiology, Medical College of Soochow University. No. 199, Ren Ai Road, Suzhou, Jiangsu, 215123, PR China
| | - Yuanyuan Li
- Department of Microbiology, Medical College of Soochow University. No. 199, Ren Ai Road, Suzhou, Jiangsu, 215123, PR China
| | - Shuyan Wu
- Department of Microbiology, Medical College of Soochow University. No. 199, Ren Ai Road, Suzhou, Jiangsu, 215123, PR China.
| | - Rui Huang
- Department of Microbiology, Medical College of Soochow University. No. 199, Ren Ai Road, Suzhou, Jiangsu, 215123, PR China.
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Abstract
The well-studied spv operon of Salmonellatyphimurium is important for causing full virulence in mice and both the regulation and function of the Spv proteins have been characterized extensively over the past several decades. Using quantitative single-cell fluorescence microscopy, we demonstrate the spv regulon to display a bimodal expression pattern that originates in the bimodal expression of the SpvR activator. The spv expression pattern is influenced by growth conditions and the specific Styphimurium strain used, but does not require Salmonella-specific virulence regulators. By monitoring real-time promoter kinetics, we reveal that SpvA has the ability to impart negative feedback on spvABCD expression without affecting spvR expression. Together, our data suggest that the SpvA protein counteracts the positive feedback loop imposed by SpvR, and could thus be responsible for dampening spvABCD expression and coordinating virulence protein production in time. The results presented here yield new insights in the intriguing regulation of the spv operon and adds this operon to the growing list of virulence factors exhibiting marked expression heterogeneity in Styphimurium.
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Affiliation(s)
- Ioannis Passaris
- Department of Microbial and Molecular Systems (MS), Katholieke Universiteit Leuven, 3001 Leuven, Belgium
| | - Alexander Cambré
- Department of Microbial and Molecular Systems (MS), Katholieke Universiteit Leuven, 3001 Leuven, Belgium
| | - Sander K Govers
- Department of Microbial and Molecular Systems (MS), Katholieke Universiteit Leuven, 3001 Leuven, Belgium
| | - Abram Aertsen
- Department of Microbial and Molecular Systems (MS), Katholieke Universiteit Leuven, 3001 Leuven, Belgium
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Wu SY, Wang LD, Xu GM, Yang SD, Deng QF, Li YY, Huang R. spv locus aggravates Salmonella infection of zebrafish adult by inducing Th1/Th2 shift to Th2 polarization. Fish Shellfish Immunol 2017; 67:684-691. [PMID: 28666864 DOI: 10.1016/j.fsi.2017.06.057] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 06/22/2017] [Accepted: 06/25/2017] [Indexed: 06/07/2023]
Abstract
Salmonella enterica serovar typhimurium (S. typhimurium) are facultative intracellular enteric pathogens causing disease with a broad range of hosts. It was known that Th1-type cytokines such as IFN-γ, IL-12, and TNF-α etc. could induce protective immunity against intracellular pathogens, while Th2-type cytokines such as IL-4, IL-10, and IL-13 etc. are proved to help pathogens survive inside hosts and cause severe infection. One of the critical virulence factor attributes to the pathogenesis of S. typhimurium is Salmonella plasmid virulence genes (spv). Until now, the interaction between spv locus and the predictable generation of Th1 or Th2 immune responses to Salmonella has not been identified. In this study, zebrafish adults were employed to explore the effect of spv locus on Salmonella pathogenesis as well as host adaptive immune responses especially shift of Th1/Th2 balance. The pathological changes of intestines and livers in zebrafish were observed by hematoxylin-eosin (HE) staining and electron microscopy. Levels of the transcription factors of Th1 (Tbx21) and Th2 (GATA3) were measured by real-time quantitative PCR (RT-qPCR). Expression of cytokines were determined by using RT-qPCR and ELISA, respectively. Results showed that spv operon aggravates damage of zebrafish. Furthermore, it demonstrated that spv locus could inhibit the transcription of tbx21 gene and suppress the expression of cytokines IFN-γ, IL-12 and TNF-α. On the contrary, the transcription of gata3 gene could be promoted and the expression of cytokines IL-4, IL-10 and IL-13 were enhanced by spv locus. Taken together, our data revealed that spv locus could aggravate Salmonella infection of zebrafish adult by inducing an imbalance of Th1/Th2 immune response and resulting in a detrimental Th2 bias of host.
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Affiliation(s)
- Shu-Yan Wu
- Department of Medical Microbiology, Medical College of Soochow University, No. 199, Ren Ai Road, Suzhou, Jiangsu 215123, PR China
| | - Li-Dan Wang
- Department of Medical Microbiology, Medical College of Soochow University, No. 199, Ren Ai Road, Suzhou, Jiangsu 215123, PR China
| | - Guang-Mei Xu
- Department of Medical Microbiology, Medical College of Soochow University, No. 199, Ren Ai Road, Suzhou, Jiangsu 215123, PR China
| | - Si-di Yang
- Department of Medical Microbiology, Medical College of Soochow University, No. 199, Ren Ai Road, Suzhou, Jiangsu 215123, PR China
| | - Qi-Feng Deng
- Department of Medical Microbiology, Medical College of Soochow University, No. 199, Ren Ai Road, Suzhou, Jiangsu 215123, PR China
| | - Yuan-Yuan Li
- Department of Medical Microbiology, Medical College of Soochow University, No. 199, Ren Ai Road, Suzhou, Jiangsu 215123, PR China
| | - Rui Huang
- Department of Medical Microbiology, Medical College of Soochow University, No. 199, Ren Ai Road, Suzhou, Jiangsu 215123, PR China.
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Hooton SPT, Timms AR, Cummings NJ, Moreton J, Wilson R, Connerton IF. The complete plasmid sequences of Salmonella enterica serovar Typhimurium U288. Plasmid 2014; 76:32-9. [PMID: 25175817 DOI: 10.1016/j.plasmid.2014.08.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 08/11/2014] [Accepted: 08/21/2014] [Indexed: 12/20/2022]
Abstract
Salmonella enterica Serovar Typhimurium U288 is an emerging pathogen of pigs. The strain contains three plasmids of diverse origin that encode traits that are of concern for food security and safety, these include antibiotic resistant determinants, an array of functions that can modify cell physiology and permit genetic mobility. At 148,711 bp, pSTU288-1 appears to be a hybrid plasmid containing a conglomerate of genes found in pSLT of S. Typhimurium LT2, coupled with a mosaic of horizontally-acquired elements. Class I integron containing gene cassettes conferring resistance against clinically important antibiotics and compounds are present in pSTU288-1. A curious feature of the plasmid involves the deletion of two genes encoded in the Salmonella plasmid virulence operon (spvR and spvA) following the insertion of a tnpA IS26-like element coupled to a blaTEM gene. The spv operon is considered to be a major plasmid-encoded Salmonella virulence factor that is essential for the intracellular lifecycle. The loss of the positive regulator SpvR may impact on the pathogenesis of S. Typhimurium U288. A second 11,067 bp plasmid designated pSTU288-2 contains further antibiotic resistance determinants, as well as replication and mobilization genes. Finally, a small 4675 bp plasmid pSTU288-3 was identified containing mobilization genes and a pleD-like G-G-D/E-E-F conserved domain protein that modulate intracellular levels of cyclic di-GMP, and are associated with motile to sessile transitions in growth.
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Affiliation(s)
- Steven P T Hooton
- Division of Food Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK
| | - Andrew R Timms
- Division of Food Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK
| | - Nicola J Cummings
- Division of Food Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK
| | - Joanna Moreton
- School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK
| | - Ray Wilson
- DeepSeq, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK
| | - Ian F Connerton
- Division of Food Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK.
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