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Sun H, Wu M, Zhang Z, Wang Y, Yang J, Liu Z, Guan G, Luo J, Yin H, Niu Q. OAS1 suppresses African swine fever virus replication by recruiting TRIM21 to degrade viral major capsid protein. J Virol 2023; 97:e0121723. [PMID: 37815352 PMCID: PMC10617512 DOI: 10.1128/jvi.01217-23] [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: 08/11/2023] [Accepted: 08/28/2023] [Indexed: 10/11/2023] Open
Abstract
IMPORTANCE African swine fever virus (ASFV) completes the replication process by resisting host antiviral response via inhibiting interferon (IFN) secretion and interferon-stimulated genes (ISGs) function. 2', 5'-Oligoadenylate synthetase gene 1 (OAS1) has been reported to inhibit the replication of various RNA and some DNA viruses. However, the regulatory mechanisms involved in the ASFV-induced IFN-related pathway still need to be fully elucidated. Here, we found that OAS1, as a critical host factor, inhibits ASFV replication in an RNaseL-dependent manner. Furthermore, overexpression of OAS1 can promote the activation of the JAK-STAT pathway promoting innate immune responses. In addition, OAS1 plays a new function, which could interact with ASFV P72 protein to suppress ASFV infection. Mechanistically, OAS1 enhances the proteasomal degradation of P72 by promoting TRIM21-mediated ubiquitination. Meanwhile, P72 inhibits the production of avSG and affects the interaction between OAS1 and DDX6. Our findings demonstrated OAS1 as an important target against ASFV replication and revealed the mechanisms and intrinsic regulatory relationships during ASFV infection.
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Affiliation(s)
- Hualin Sun
- African Swine Fever Regional Laboratory, China (Lanzhou); State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University; Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Mengli Wu
- African Swine Fever Regional Laboratory, China (Lanzhou); State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University; Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Zhonghui Zhang
- African Swine Fever Regional Laboratory, China (Lanzhou); State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University; Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Yiwang Wang
- African Swine Fever Regional Laboratory, China (Lanzhou); State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University; Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Jifei Yang
- African Swine Fever Regional Laboratory, China (Lanzhou); State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University; Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Zhijie Liu
- African Swine Fever Regional Laboratory, China (Lanzhou); State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University; Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Guiquan Guan
- African Swine Fever Regional Laboratory, China (Lanzhou); State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University; Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Jianxun Luo
- African Swine Fever Regional Laboratory, China (Lanzhou); State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University; Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Hong Yin
- African Swine Fever Regional Laboratory, China (Lanzhou); State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University; Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonosis, Yangzhou University, Yangzhou, China
| | - Qingli Niu
- African Swine Fever Regional Laboratory, China (Lanzhou); State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University; Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
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Yi H, Wang Q, Lu L, Ye R, Xie E, Yu Z, Sun Y, Chen Y, Cai M, Qiu Y, Wu Q, Peng J, Wang H, Zhang G. PSMB4 Degrades the Porcine Reproductive and Respiratory Syndrome Virus Nsp1α Protein via the Autolysosome Pathway and Induces the Production of Type I Interferon. J Virol 2023; 97:e0026423. [PMID: 36943051 PMCID: PMC10134815 DOI: 10.1128/jvi.00264-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 02/27/2023] [Indexed: 03/23/2023] Open
Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV) causes respiratory disease in pigs of all ages and reproductive failure in sows, resulting in great economic losses to the swine industry. In this work, we identified the interaction between PSMB4 and PRRSV Nsp1α by yeast two-hybrid screening. The PSMB4-Nsp1α interaction was further confirmed by coimmunoprecipitation, glutathione S-transferase (GST) pulldown, and laser confocal experiments. The PCPα domain (amino acids 66 to 166) of Nsp1α and the C-terminal domain (amino acids 250 to 264) of PSMB4 were shown to be critical for the PSMB4-Nsp1α interaction. PSMB4 overexpression reduced PRRSV replication, whereas PSMB4 knockdown elicited opposing effects. Mechanistically, PSMB4 targeted K169 in Nsp1α for K63-linked ubiquitination and targeted Nsp1α for autolysosomal degradation by interacting with LC3 to enhance the activation of the lysosomal pathway. Meanwhile, we found that PSMB4 activated the NF-κB signaling pathway to produce type I interferons by downregulating the expression of IκBα and p-IκBα. In conclusion, our data revealed a new mechanism of PSMB4-mediated restriction of PRRSV replication, whereby PSMB4 was found to induce Nsp1α degradation and type I interferon expression, in order to impede the replication of PRRSV. IMPORTANCE In the swine industry, PRRSV is a continuous threat, and the current vaccines are not effective enough to block it. This study determined that PSMB4 plays an antiviral role against PRRSV. PSMB4 was found to interact with PRRSV Nsp1α, mediate K63-linked ubiquitination of Nsp1α at K169, and thus trigger its degradation via the lysosomal pathway. Additionally, PSMB4 activated the NF-κB signaling pathway to produce type I interferons by downregulating the expression of IκBα and p-IκBα. This study extends our understanding of the proteasome subunit PSMB4 against PRRSV replication and will contribute to the development of new antiviral strategies.
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Affiliation(s)
- Heyou Yi
- Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Maoming Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Maoming, China
- National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou, China
| | - Qiumei Wang
- Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Lechen Lu
- Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Ruirui Ye
- Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Ermin Xie
- Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Zhiqing Yu
- Key Laboratory of Veterinary Bioproduction and Chemical Medicine of the Ministry of Agriculture, Engineering and Technology Research Center for Beijing Veterinary Peptide Vaccine Design and Preparation, Zhongmu Institutes of China Animal Husbandry Industry Co. Ltd., Beijing, China
| | - Yankuo Sun
- Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Maoming Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Maoming, China
- National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou, China
| | - Yao Chen
- School of Life Science and Engineering, Foshan University, Foshan, China
| | - Mengkai Cai
- Guangdong Meizhou Vocational and Technical College, Meizhou, China
| | - Yingwu Qiu
- Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Qianwen Wu
- Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Jie Peng
- Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Heng Wang
- Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Maoming Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Maoming, China
- National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou, China
| | - Guihong Zhang
- Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Maoming Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Maoming, China
- National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou, China
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3
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Panagi I, Thurston TL. Ready, STAT3, Go! Bacteria in the race for M2 macrophage polarisation. Curr Opin Microbiol 2023; 73:102285. [PMID: 36857844 DOI: 10.1016/j.mib.2023.102285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 01/20/2023] [Accepted: 01/25/2023] [Indexed: 03/03/2023]
Abstract
Despite macrophages representing professional immune cells that are integral to the host defences against microbial threats, several intracellular bacteria not only infect, but survive, replicate and often persist in these cells. This is perhaps possible because not all macrophages are the same. Instead, macrophages are loosely divided into two classes: the M1 'classically activated' pro-inflammatory subset and the M2 'alternatively activated' cells that are generally anti-inflammatory and infection-permissive. In this review, we summarise recent findings explaining how several intracellular pathogens, often using secreted effectors, rewire host circuitry in favour of an anti-inflammatory niche. A common theme is the phosphorylation and activation of the signal transducer and activator of transcription-3 (STAT3) transcription factor. We describe and compare the diverse mechanisms employed and reflect how such non-canonical processes may have evolved to circumvent regulation by the host, providing a potent means by which different pathogens manipulate the cells they infect.
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Affiliation(s)
- Ioanna Panagi
- MRC Centre for Molecular Bacteriology and Infection, Department of Infectious Disease, Imperial College London, SW7 2AZ, UK
| | - Teresa Lm Thurston
- MRC Centre for Molecular Bacteriology and Infection, Department of Infectious Disease, Imperial College London, SW7 2AZ, UK.
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Zhao T, Liu C, Liu L, Wang X, Liu C. Aging-accelerated differential production and aggregation of STAT3 protein in neuronal cells and neural stem cells in the male mouse spinal cord. Biogerontology 2023; 24:137-148. [PMID: 36550376 DOI: 10.1007/s10522-022-10004-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 11/29/2022] [Indexed: 12/24/2022]
Abstract
Aging-affected cellular compositions of the spinal cord are diverse and region specific. Age leads to the accumulation of abnormal protein aggregates and dysregulation of proteostasis. Dysregulated proteostasis and protein aggregates result from dysfunction of the ubiquitin-proteasome system (UPS) and autophagy. Understanding the molecular mechanisms of spinal cord aging is essential and important for scientists to discover new therapies for rejuvenation. We found age-related increases in STAT3 and decreases in Tuj1 in aging mouse spinal cords, which was characterized by increased expression of P16. Coaggregation of lysine-48 and lysine-63 ubiquitin with STAT3 was revealed in aging mouse spinal cords. STAT3-ubiquitin aggregates formed via lysine-48 and lysine-63 linkages were increased significantly in the aging spinal cords but not in central canal ependymal cells or neural stem cells in the spinal cord. These results highlight the increase in STAT3 and its region-specific aggregation and ubiquitin-conjugation during spinal cord aging.
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Affiliation(s)
- Tianyi Zhao
- Department of Histology and Embryology, School of Basic Medical Sciences, Institute of Stem Cell and Tissue Engineering, Anhui Medical University, 81 Meishan Road, Hefei, 230032, Anhui, China
| | - Chang Liu
- Department of Orthopedics and Spine Surgery, The First Affiliated Hospital, Anhui Medical University, Hefei, 230032, Anhui, China
| | - Lihua Liu
- Institute of Clinical Pharmacology, Anhui Medical University, Hefei, 230032, Anhui, China
| | - Xinmeng Wang
- Department of Histology and Embryology, School of Basic Medical Sciences, Institute of Stem Cell and Tissue Engineering, Anhui Medical University, 81 Meishan Road, Hefei, 230032, Anhui, China
| | - Chao Liu
- Department of Histology and Embryology, School of Basic Medical Sciences, Institute of Stem Cell and Tissue Engineering, Anhui Medical University, 81 Meishan Road, Hefei, 230032, Anhui, China.
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5
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Fromm K, Boegli A, Ortelli M, Wagner A, Bohn E, Malmsheimer S, Wagner S, Dehio C. Bartonella taylorii: A Model Organism for Studying Bartonella Infection in vitro and in vivo. Front Microbiol 2022; 13:913434. [PMID: 35910598 PMCID: PMC9336547 DOI: 10.3389/fmicb.2022.913434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 05/05/2022] [Indexed: 11/13/2022] Open
Abstract
Bartonella spp. are Gram-negative facultative intracellular pathogens that infect diverse mammals and cause a long-lasting intra-erythrocytic bacteremia in their natural host. These bacteria translocate Bartonella effector proteins (Beps) into host cells via their VirB/VirD4 type 4 secretion system (T4SS) in order to subvert host cellular functions, thereby leading to the downregulation of innate immune responses. Most studies on the functional analysis of the VirB/VirD4 T4SS and the Beps were performed with the major zoonotic pathogen Bartonella henselae for which efficient in vitro infection protocols have been established. However, its natural host, the cat, is unsuitable as an experimental infection model. In vivo studies were mostly confined to rodent models using rodent-specific Bartonella species, while the in vitro infection protocols devised for B. henselae are not transferable for those pathogens. The disparities of in vitro and in vivo studies in different species have hampered progress in our understanding of Bartonella pathogenesis. Here we describe the murine-specific strain Bartonella taylorii IBS296 as a new model organism facilitating the study of bacterial pathogenesis both in vitro in cell cultures and in vivo in laboratory mice. We implemented the split NanoLuc luciferase-based translocation assay to study BepD translocation through the VirB/VirD4 T4SS. We found increased effector-translocation into host cells if the bacteria were grown on tryptic soy agar (TSA) plates and experienced a temperature shift immediately before infection. The improved infectivity in vitro was correlating to an upregulation of the VirB/VirD4 T4SS. Using our adapted infection protocols, we showed BepD-dependent immunomodulatory phenotypes in vitro. In mice, the implemented growth conditions enabled infection by a massively reduced inoculum without having an impact on the course of the intra-erythrocytic bacteremia. The established model opens new avenues to study the role of the VirB/VirD4 T4SS and the translocated Bep effectors in vitro and in vivo.
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Affiliation(s)
- Katja Fromm
- Biozentrum, University of Basel, Basel, Switzerland
| | - Alexandra Boegli
- Department of Biochemistry, Faculty of Biology and Medicine, Université de Lausanne, Epalinges, Switzerland
| | | | | | - Erwin Bohn
- Institute of Medical Microbiology and Hygiene, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), University of Tübingen, Tübingen, Germany
| | - Silke Malmsheimer
- Section of Cellular and Molecular Microbiology, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), University of Tübingen, Tübingen, Germany
| | - Samuel Wagner
- Section of Cellular and Molecular Microbiology, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), University of Tübingen, Tübingen, Germany
- Excellence Cluster “Controlling Microbes to Fight Infections” (CMFI), Tübingen, Germany
- Partner-site Tübingen, German Center for Infection Research (DZIF), Tübingen, Germany
| | - Christoph Dehio
- Biozentrum, University of Basel, Basel, Switzerland
- *Correspondence: Christoph Dehio,
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6
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Fromm K, Dehio C. The Impact of Bartonella VirB/VirD4 Type IV Secretion System Effectors on Eukaryotic Host Cells. Front Microbiol 2022; 12:762582. [PMID: 34975788 PMCID: PMC8714903 DOI: 10.3389/fmicb.2021.762582] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Accepted: 10/29/2021] [Indexed: 12/14/2022] Open
Abstract
Bartonella spp. are facultative intracellular pathogens that infect a wide range of mammalian hosts including humans. The VirB/VirD4 type IV secretion system (T4SS) is a key virulence factor utilized to translocate Bartonella effector proteins (Beps) into host cells in order to subvert their functions. Crucial for effector translocation is the C-terminal Bep intracellular delivery (BID) domain that together with a positively charged tail sequence forms a bipartite translocation signal. Multiple BID domains also evolved secondary effector functions within host cells. The majority of Beps possess an N-terminal filamentation induced by cAMP (FIC) domain and a central connecting oligonucleotide binding (OB) fold. FIC domains typically mediate AMPylation or related post-translational modifications of target proteins. Some Beps harbor other functional modules, such as tandem-repeated tyrosine-phosphorylation (EPIYA-related) motifs. Within host cells the EPIYA-related motifs are phosphorylated, which facilitates the interaction with host signaling proteins. In this review, we will summarize our current knowledge on the molecular functions of the different domains present in Beps and highlight examples of Bep-dependent host cell modulation.
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Affiliation(s)
- Katja Fromm
- Biozentrum, University of Basel, Basel, Switzerland
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7
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Zhou Q, Zhang J. K27-linked noncanonic ubiquitination in immune regulation. J Leukoc Biol 2021; 111:223-235. [PMID: 33857334 DOI: 10.1002/jlb.4ru0620-397rr] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 03/05/2021] [Accepted: 03/10/2021] [Indexed: 12/16/2022] Open
Abstract
Ubiquitination is a common form of posttranslational modification that has been implicated in regulating considerable immune signaling pathways. The functions of canonic K48- and K63-linked ubiquitination have been well studied. However, the roles of noncanonic ubiquitination remain largely unexplored and require further investigations. There is increasing evidence suggesting that K27-linked noncanonic ubiquitination turns out to be indispensable to both innate immune signaling and T cell signaling. In this review, we provide an overview of the latest findings related to K27-linked ubiquitination, and highlight the crucial roles of K27-linked ubiquitination in regulating antimicrobial response, cytokine signaling and response, as well as T cell activation and differentiation. We also propose interesting areas for better understanding how K27-linked ubiquitination regulates immunity.
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Affiliation(s)
- Qingqing Zhou
- Department of Immunology, School of Basic Medical Sciences, NHC Key Laboratory of Medical Immunology (Peking University), Peking University Health Science Center, Beijing, China
| | - Jun Zhang
- Department of Immunology, School of Basic Medical Sciences, NHC Key Laboratory of Medical Immunology (Peking University), Peking University Health Science Center, Beijing, China
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Marlaire S, Dehio C. Bartonella effector protein C mediates actin stress fiber formation via recruitment of GEF-H1 to the plasma membrane. PLoS Pathog 2021; 17:e1008548. [PMID: 33508040 PMCID: PMC7842960 DOI: 10.1371/journal.ppat.1008548] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 10/09/2020] [Indexed: 02/06/2023] Open
Abstract
Bartonellae are Gram-negative facultative-intracellular pathogens that use a type-IV-secretion system (T4SS) to translocate a cocktail of Bartonella effector proteins (Beps) into host cells to modulate diverse cellular functions. BepC was initially reported to act in concert with BepF in triggering major actin cytoskeletal rearrangements that result in the internalization of a large bacterial aggregate by the so-called ‘invasome’. Later, infection studies with bepC deletion mutants and ectopic expression of BepC have implicated this effector in triggering an actin-dependent cell contractility phenotype characterized by fragmentation of migrating cells due to deficient rear detachment at the trailing edge, and BepE was shown to counterbalance this remarkable phenotype. However, the molecular mechanism of how BepC triggers cytoskeletal changes and the host factors involved remained elusive. Using infection assays, we show here that T4SS-mediated transfer of BepC is sufficient to trigger stress fiber formation in non-migrating epithelial cells and additionally cell fragmentation in migrating endothelial cells. Interactomic analysis revealed binding of BepC to a complex of the Rho guanine nucleotide exchange factor GEF-H1 and the serine/threonine-protein kinase MRCKα. Knock-out cell lines revealed that only GEF-H1 is required for mediating BepC-triggered stress fiber formation and inhibitor studies implicated activation of the RhoA/ROCK pathway downstream of GEF-H1. Ectopic co-expression of tagged versions of GEF-H1 and BepC truncations revealed that the C-terminal ‘Bep intracellular delivery’ (BID) domain facilitated anchorage of BepC to the plasma membrane, whereas the N-terminal ‘filamentation induced by cAMP’ (FIC) domain facilitated binding of GEF-H1. While FIC domains typically mediate post-translational modifications, most prominently AMPylation, a mutant with quadruple amino acid exchanges in the putative active site indicated that the BepC FIC domain acts in a non-catalytic manner to activate GEF-H1. Our data support a model in which BepC activates the RhoA/ROCK pathway by re-localization of GEF-H1 from microtubules to the plasma membrane. A wide variety of bacterial pathogens evolved numerous virulence factors to subvert cellular processes in support of a successful infection process. Likewise, bacteria of the genus Bartonella translocate a cocktail of effector proteins (Beps) via a type-IV-secretion system into infected cells in order to interfere with host signaling processes involved in cytoskeletal dynamics, apoptosis control, and innate immune responses. In this study, we demonstrate that BepC triggers actin stress fiber formation and a linked cell fragmentation phenotype resulting from distortion of rear-end retraction during cell migration. The ability of BepC to induce actin stress fiber formation is directly associated with its ability to bind GEF-H1, an activator of the RhoA pathway that is sequestered in an inactive state when bound to microtubules but becomes activated upon release to the cytoplasm. Our findings suggest that BepC is anchored via its BID domain to the plasma membrane where it recruits GEF-H1 via its FIC domain, eventually activating the RhoA/ROCK signaling pathway and leading to stress fiber formation.
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Affiliation(s)
| | - Christoph Dehio
- Biozentrum, University of Basel, Basel, Switzerland
- * E-mail:
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9
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Wang C, Zhang H, Fu J, Wang M, Cai Y, Ding T, Jiang J, Koehler JE, Liu X, Yuan C. Bartonella type IV secretion effector BepC induces stress fiber formation through activation of GEF-H1. PLoS Pathog 2021; 17:e1009065. [PMID: 33508039 PMCID: PMC7842913 DOI: 10.1371/journal.ppat.1009065] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 10/13/2020] [Indexed: 12/27/2022] Open
Abstract
Bartonella T4SS effector BepC was reported to mediate internalization of big Bartonella aggregates into host cells by modulating F-actin polymerization. After that, BepC was indicated to induce host cell fragmentation, an interesting cell phenotype that is characterized by failure of rear-end retraction during cell migration, and subsequent dragging and fragmentation of cells. Here, we found that expression of BepC resulted in significant stress fiber formation and contractile cell morphology, which depended on combination of the N-terminus FIC (filamentation induced by c-AMP) domain and C-terminus BID (Bartonellaintracellular delivery) domain of BepC. The FIC domain played a key role in BepC-induced stress fiber formation and cell fragmentation because deletion of FIC signature motif or mutation of two conserved amino acid residues abolished BepC-induced cell fragmentation. Immunoprecipitation confirmed the interaction of BepC with GEF-H1 (a microtubule-associated RhoA guanosine exchange factor), and siRNA-mediated depletion of GEF-H1 prevented BepC-induced stress fiber formation. Interaction with BepC caused the dissociation of GEF-H1 from microtubules and activation of RhoA to induce formation of stress fibers. The ROCK (Rho-associated protein kinase) inhibitor Y27632 completely blocked BepC effects on stress fiber formation and cell contractility. Moreover, stress fiber formation by BepC increased the stability of focal adhesions, which consequently impeded rear-edge detachment. Overall, our study revealed that BepC-induced stress fiber formation was achieved through the GEF-H1/RhoA/ROCK pathway. Intracellular pathogens modulate host cell actin cytoskeleton by secreting an array of effector molecules to ensure their cell invasion and intracellular survival. The zoonotic pathogen Bartonella spp trigger massive F-actin polymerization of host cells resulting the internalization of large bacterial aggregates (called “invasome” structure), which is dependent on a functional VirB/VirD4 type IV secretion system (T4SS) and its translocated Bep effector proteins. Here, we have used cell infection and ectopic expression assay to identify that Bartonella T4SS effector BepC induces stress fiber formation in infected host cells. However, BepC also disrupts the balance of stress fiber formation and focal adhesion maturation, and eventually causes cell fragmentation. Using immunoprecipitation and RNAi approaches, we identify GEF-H1 is the host factor targeted by BepC. Interaction with BepC induces the release of GEF-H1 from microtubules to plasma membrane and subsequently activates RhoA-ROCK to induce stress fiber formation. These findings shed light on our understanding of how Bartonella invade host cell and establish infection.
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Affiliation(s)
- Chunyan Wang
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Veterinary Biotechnology, Shanghai, China
| | - Haoran Zhang
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Veterinary Biotechnology, Shanghai, China
| | - Jiaqi Fu
- Institute of Analytical Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Meng Wang
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Veterinary Biotechnology, Shanghai, China
| | - Yuhao Cai
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Veterinary Biotechnology, Shanghai, China
| | - Tianyun Ding
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Veterinary Biotechnology, Shanghai, China
| | - Jiezhang Jiang
- Institute of Analytical Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Jane E. Koehler
- Department of Medicine, Division of Infectious Diseases, and the Microbial Pathogenesis and Host Defense Program, University of California, San Francisco, California, United States of America
| | - Xiaoyun Liu
- Department of Microbiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
- * E-mail: (XL); (CY)
| | - Congli Yuan
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Veterinary Biotechnology, Shanghai, China
- * E-mail: (XL); (CY)
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10
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Jiao Y, Sun J. Bacterial Manipulation of Autophagic Responses in Infection and Inflammation. Front Immunol 2019; 10:2821. [PMID: 31849988 PMCID: PMC6901625 DOI: 10.3389/fimmu.2019.02821] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Accepted: 11/15/2019] [Indexed: 01/07/2023] Open
Abstract
Eukaryotes have cell-autonomous defenses against environmental stress and pathogens. Autophagy is one of the main cellular defenses against intracellular bacteria. In turn, bacteria employ diverse mechanisms to interfere with autophagy initiation and progression to avoid elimination and even to subvert autophagy for their benefit. This review aims to discuss recent findings regarding the autophagic responses regulated by bacterial effectors. Effectors manipulate autophagy at different stages by using versatile strategies, such as interfering with autophagy-initiating signaling, preventing the recognition of autophagy-involved proteins, subverting autophagy component homeostasis, manipulating the autophagy process, and impacting other biological processes. We describe the barriers for intracellular bacteria in host cells and highlight the role of autophagy in the host-microbial interactions. Understanding the mechanisms through which bacterial effectors manipulate host responses will provide new insights into therapeutic approaches for prevention and treatment of chronic inflammation and infectious diseases.
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Affiliation(s)
- Yang Jiao
- Division of Gastroenterology and Hepatology, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States
| | - Jun Sun
- Division of Gastroenterology and Hepatology, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States
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Hong J, Luo Y, Mou M, Fu J, Zhang Y, Xue W, Xie T, Tao L, Lou Y, Zhu F. Convolutional neural network-based annotation of bacterial type IV secretion system effectors with enhanced accuracy and reduced false discovery. Brief Bioinform 2019; 21:1825-1836. [PMID: 31860715 DOI: 10.1093/bib/bbz120] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Revised: 08/12/2019] [Accepted: 08/21/2019] [Indexed: 12/20/2022] Open
Abstract
The type IV bacterial secretion system (SS) is reported to be one of the most ubiquitous SSs in nature and can induce serious conditions by secreting type IV SS effectors (T4SEs) into the host cells. Recent studies mainly focus on annotating new T4SE from the huge amount of sequencing data, and various computational tools are therefore developed to accelerate T4SE annotation. However, these tools are reported as heavily dependent on the selected methods and their annotation performance need to be further enhanced. Herein, a convolution neural network (CNN) technique was used to annotate T4SEs by integrating multiple protein encoding strategies. First, the annotation accuracies of nine encoding strategies integrated with CNN were assessed and compared with that of the popular T4SE annotation tools based on independent benchmark. Second, false discovery rates of various models were systematically evaluated by (1) scanning the genome of Legionella pneumophila subsp. ATCC 33152 and (2) predicting the real-world non-T4SEs validated using published experiments. Based on the above analyses, the encoding strategies, (a) position-specific scoring matrix (PSSM), (b) protein secondary structure & solvent accessibility (PSSSA) and (c) one-hot encoding scheme (Onehot), were identified as well-performing when integrated with CNN. Finally, a novel strategy that collectively considers the three well-performing models (CNN-PSSM, CNN-PSSSA and CNN-Onehot) was proposed, and a new tool (CNN-T4SE, https://idrblab.org/cnnt4se/) was constructed to facilitate T4SE annotation. All in all, this study conducted a comprehensive analysis on the performance of a collection of encoding strategies when integrated with CNN, which could facilitate the suppression of T4SS in infection and limit the spread of antimicrobial resistance.
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Affiliation(s)
- Jiajun Hong
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Yongchao Luo
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Minjie Mou
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Jianbo Fu
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Yang Zhang
- School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, China
| | - Weiwei Xue
- School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, China
| | - Tian Xie
- Key Laboratory of Elemene Class Anti-Cancer Chinese Medicine of Zhejiang Province, School of Medicine, Hangzhou Normal University, Hangzhou 310036, China
| | - Lin Tao
- Key Laboratory of Elemene Class Anti-Cancer Chinese Medicine of Zhejiang Province, School of Medicine, Hangzhou Normal University, Hangzhou 310036, China
| | - Yan Lou
- Zhejiang Provincial Key Laboratory for Drug Clinical Research and Evaluation, The First Affiliated Hospital, Zhejiang University, Hangzhou 310000, Zhejiang, China
| | - Feng Zhu
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
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Wagner A, Tittes C, Dehio C. Versatility of the BID Domain: Conserved Function as Type-IV-Secretion-Signal and Secondarily Evolved Effector Functions Within Bartonella-Infected Host Cells. Front Microbiol 2019; 10:921. [PMID: 31130928 PMCID: PMC6509941 DOI: 10.3389/fmicb.2019.00921] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 04/11/2019] [Indexed: 11/13/2022] Open
Abstract
Bartonella spp. are facultative intracellular pathogens that infect a wide range of mammalian hosts including humans. In order to subvert cellular functions and the innate immune response of their hosts, these pathogens utilize a VirB/VirD4 type-IV-secretion (T4S) system to translocate Bartonella effector proteins (Beps) into host cells. Crucial for this process is the Bep intracellular delivery (BID) domain that together with a C-terminal stretch of positively charged residues constitutes a bipartite T4S signal. This function in T4S is evolutionarily conserved with BID domains present in bacterial toxins and relaxases. Strikingly, some BID domains of Beps have evolved secondary functions to modulate host cell and innate immune pathways in favor of Bartonella infection. For instance, BID domains mediate F-actin-dependent bacterial internalization, inhibition of apoptosis, or modulate cell migration. Recently, crystal structures of three BID domains from different Beps have been solved, revealing a conserved fold formed by a four-helix bundle topped with a hook. While the conserved BID domain fold might preserve its genuine role in T4S, the highly variable surfaces characteristic for BID domains may facilitate secondary functions. In this review, we summarize our current knowledge on evolutionary and structural traits as well as functional aspects of the BID domain with regard to T4S and pathogenesis.
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Affiliation(s)
| | - Colin Tittes
- Biozentrum, University of Basel, Basel, Switzerland
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