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Dahmani M, Zhu JC, Cook JH, Riley SP. Anaphylatoxin signaling activates macrophages to control intracellular Rickettsia proliferation. Microbiol Spectr 2023; 11:e0253823. [PMID: 37855623 PMCID: PMC10714731 DOI: 10.1128/spectrum.02538-23] [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: 06/20/2023] [Accepted: 09/11/2023] [Indexed: 10/20/2023] Open
Abstract
IMPORTANCE Pathogenic Rickettsia species are extremely dangerous bacteria that grow within the cytoplasm of host mammalian cells. In most cases, these bacteria are able to overpower the host cell and grow within the protected environment of the cytoplasm. However, a dramatic conflict occurs when Rickettsia encounter innate immune cells; the bacteria can "win" by taking over the host, or the bacteria can "lose" if the host cell efficiently fights the infection. This manuscript examines how the immune complement system is able to detect the presence of Rickettsia and alert nearby cells. Byproducts of complement activation called anaphylatoxins are signals that "activate" innate immune cells to mount an aggressive defensive strategy. This study enhances our collective understanding of the innate immune reaction to intracellular bacteria and will contribute to future efforts at controlling these dangerous infections.
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Affiliation(s)
- Mustapha Dahmani
- Department of Veterinary Medicine, University of Maryland-College Park, College Park, Maryland, USA
| | - Jinyi C. Zhu
- Department of Veterinary Medicine, University of Maryland-College Park, College Park, Maryland, USA
| | - Jack H. Cook
- Department of Veterinary Medicine, University of Maryland-College Park, College Park, Maryland, USA
| | - Sean P. Riley
- Department of Veterinary Medicine, University of Maryland-College Park, College Park, Maryland, USA
- Virginia-Maryland College of Veterinary Medicine, College Park, Maryland, USA
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2
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Eskeland S, Bø-Granquist EG, Stuen S, Lybeck K, Wilhelmsson P, Lindgren PE, Makvandi-Nejad S. Temporal patterns of gene expression in response to inoculation with a virulent Anaplasma phagocytophilum strain in sheep. Sci Rep 2023; 13:20399. [PMID: 37989861 PMCID: PMC10663591 DOI: 10.1038/s41598-023-47801-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 11/18/2023] [Indexed: 11/23/2023] Open
Abstract
The aim of this study was to characterize the gene expression of host immune- and cellular responses to a Norwegian virulent strain of Anaplasma phagocytophilum, the cause of tick-borne fever in sheep. Ten sheep were intravenously inoculated with a live virulent strain of A. phagocytophilum. Clinical-, observational-, hematological data as well as bacterial load, flow cytometric cell count data from peripheral blood mononuclear cells and host's gene expression post infection was analysed. The transcriptomic data were assessed for pre-set time points over the course of 22 days following the inoculation. Briefly, all inoculated sheep responded with clinical signs of infection 3 days post inoculation and onwards with maximum bacterial load observed on day 6, consistent with tick-borne fever. On days, 3-8, the innate immune responses and effector processes such as IFN1 signaling pathways and cytokine mediated signaling pathways were observed. Several pathways associated with the adaptive immune responses, namely T-cell activation, humoral immune responses, B-cell activation, and T- and B-cell differentiation dominated on the days of 8, 10 and 14. Flow-cytometric analysis of the PBMCs showed a reduction in CD4+CD25+ cells on day 10 and 14 post-inoculation and a skewed CD4:CD8 ratio indicating a reduced activation and proliferation of CD4-T-cells. The genes of important co-stimulatory molecules such as CD28 and CD40LG, important in T- and B-cell activation and proliferation, did not significantly change or experienced downregulation throughout the study. The absence of upregulation of several co-stimulatory molecules might be one possible explanation for the low activation and proliferation of CD4-T-cells during A. phagocytophilum infection, indicating a suboptimal CD4-T-cell response. The upregulation of T-BET, EOMES and IFN-γ on days 8-14 post inoculation, indicates a favoured CD4 Th1- and CD8-response. The dynamics and interaction between CD4+CD25+ and co-stimulatory molecules such as CD28, CD80, CD40 and CD40LG during infection with A. phagocytophilum in sheep needs further investigation in the future.
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Affiliation(s)
- Sveinung Eskeland
- Department of Production Animal Clinical Science, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Elizabeth Stephansens Vei 15, 1433, Ås, Norway.
| | - Erik G Bø-Granquist
- Department of Production Animal Clinical Science, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Elizabeth Stephansens Vei 15, 1433, Ås, Norway
| | - Snorre Stuen
- Department of Production Animal Clinical Science, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Kyrkjevegen 332/334, 4325, Sandnes, Norway
| | - Kari Lybeck
- Norwegian Veterinary Institute, Elizabeth Stephansens Vei 1, 1433, Ås, Norway
| | - Peter Wilhelmsson
- Division of Clinical Microbiology, Laboratory Medicine, National Reference Laboratory for Borrelia and Other Tick-Borne Bacteria, Region Jönköping County, 553 05, Jönköping, Sweden
| | - Per-Eric Lindgren
- Division of Inflammation and Infection, Department of Biomedical and Clinical Sciences, Linköping University, 581 83, Linköping, Sweden
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Sethi SK, Dhaliwal M, Raghunathan V, Raaj H, Mahato SK, Vadhera A, Dragon-Durey MA, Jha PK, Bansal SB, Raina R. Siblings with complement activation, thrombotic microangiopathy and gangrene: Answers. Pediatr Nephrol 2022; 37:2057-2058. [PMID: 35166915 DOI: 10.1007/s00467-022-05464-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 01/04/2022] [Indexed: 10/19/2022]
Affiliation(s)
- Sidharth Kumar Sethi
- Pediatric Nephrology, Kidney Institute, Medanta, The Medicity, Gurgaon, Haryana, 122001, India
| | - Maninder Dhaliwal
- Pediatric Critical Care, Medanta, The Medicity, Gurgaon, Haryana, India, 122001
| | - Veena Raghunathan
- Pediatric Critical Care, Medanta, The Medicity, Gurgaon, Haryana, India, 122001
| | - Hritik Raaj
- Maulana Azad Medical College, New Delhi, 110002, India
| | | | | | | | - Pranaw Kumar Jha
- Kidney Institute, Medanta, The Medicity, Gurgaon, Haryana, 122001, India
| | | | - Rupesh Raina
- Pediatric Nephrology, Akron Children's Hospital, Akron, OH, USA.
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Lee H, Wang L, Ni FF, Yang XY, Feng SP, Gao XJ, Chi H, Luo YT, Chen XL, Yang BH, Wan JL, Jiao J, Wu DQ, Zhang GF, Wang M, Yang HP, Chan H, Li Q. Association between HLA alleles and sub-phenotype of childhood steroid-sensitive nephrotic syndrome. World J Pediatr 2022; 18:109-119. [PMID: 34973118 PMCID: PMC8843916 DOI: 10.1007/s12519-021-00489-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 11/11/2021] [Indexed: 10/26/2022]
Abstract
BACKGROUND Few studies have addressed the effects of human leukocyte antigen (HLA) alleles on different clinical sub-phenotypes in childhood steroid-sensitive nephrotic syndrome (SSNS), including SSNS without recurrence (SSNSWR) and steroid-dependent nephrotic syndrome/frequently relapse nephrotic syndrome (SDNS/FRNS). In this study, we investigated the relationship between HLA system and children with SSNSWR and SDNS/FRNS and clarified the value of HLA allele detection for precise typing of childhood SSNS. METHODS A total of 241 Chinese Han individuals with SSNS were genotyped using GenCap-WES Capture Kit, and four-digit resolution HLA alleles were imputed from available Genome Wide Association data. The distribution and carrying frequency of HLA alleles in SSNSWR and SDNS/FRNS were investigated. Additionally, logistic regression and mediating effects were used to examine the relationship between risk factors for disease process and HLA system. RESULTS Compared with SSNSWR, significantly decreased serum levels of complement 3 (C3) and complement 4 (C4) at onset were detected in SDNS/FRNS (C3, P < 0.001; C4, P = 0.018). The average time to remission after sufficient initial steroid treatment in SDNS/FRNS was significantly longer than that in SSNSWR (P = 0.0001). Low level of C4 was further identified as an independent risk factor for SDNS/FRNS (P = 0.008, odds ratio = 0.174, 95% confidence interval 0.048-0.630). The HLA-A*11:01 allele was independently associated with SSNSWR and SDNS/FRNS (P = 0.0012 and P = 0.0006, respectively). No significant HLA alleles were detected between SSNSWR and SDNS/FRNS. In addition, a mediating effect among HLA-I alleles (HLA-B*15:11, HLA-B*44:03 and HLA-C*07:06), C4 level and SDNS/FRNS was identified. CONCLUSIONS HLA-I alleles provide novel genetic markers for SSNSWR and SDNS/FRNS. HLA-I antigens may be involved in steroid dependent or frequent relapse in children with SSNS as mediators of immunoregulation.
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Affiliation(s)
- Hao Lee
- grid.488412.3Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Li Wang
- Department of Nephrology, Chengdu Women and Children Central Hospital, Chengdu, 610041 China
| | - Fen-Fen Ni
- grid.452787.b0000 0004 1806 5224Department of Nephrology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Xue-Ying Yang
- grid.488412.3Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Shi-Pin Feng
- Department of Nephrology, Chengdu Women and Children Central Hospital, Chengdu, 610041 China
| | - Xiao-Jie Gao
- grid.452787.b0000 0004 1806 5224Department of Nephrology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Huan Chi
- grid.488412.3Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Ye-Tao Luo
- grid.488412.3Department of Statistics, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Xue-Lan Chen
- grid.488412.3Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Bao-Hui Yang
- grid.488412.3Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Jun-Li Wan
- grid.488412.3Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Jia Jiao
- grid.488412.3Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Dao-Qi Wu
- grid.488412.3Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Gao-Fu Zhang
- grid.488412.3Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Mo Wang
- grid.488412.3Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Hai-Ping Yang
- grid.488412.3Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Han Chan
- Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China.
| | - Qiu Li
- Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China.
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5
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The Retropepsin-Type Protease APRc as a Novel Ig-Binding Protein and Moonlighting Immune Evasion Factor of Rickettsia. mBio 2021; 12:e0305921. [PMID: 34872352 PMCID: PMC8649778 DOI: 10.1128/mbio.03059-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Rickettsiae are obligate intracellular Gram-negative bacteria transmitted by arthropod vectors. Despite their reduced genomes, the function(s) of the majority of rickettsial proteins remains to be uncovered. APRc is a highly conserved retropepsin-type protease, suggested to act as a modulator of other rickettsial surface proteins with a role in adhesion/invasion. However, APRc’s function(s) in bacterial pathogenesis and virulence remains unknown. This study demonstrates that APRc targets host serum components, combining nonimmune immunoglobulin (Ig)-binding activity with resistance to complement-mediated killing. We confirmed nonimmune human IgG binding in extracts of different rickettsial species and intact bacteria. Our results revealed that the soluble domain of APRc is capable of binding to human (h), mouse, and rabbit IgG and different classes of human Ig (IgG, IgM, and IgA) in a concentration-dependent manner. APRc-hIgG interaction was confirmed with total hIgG and normal human serum. APRc-hIgG displayed a binding affinity in the micromolar range. We provided evidence of interaction preferentially through the Fab region and confirmed that binding is independent of catalytic activity. Mapping the APRc region responsible for binding revealed the segment between amino acids 157 and 166 as one of the interacting regions. Furthermore, we demonstrated that expression of the full-length protease in Escherichia coli is sufficient to promote resistance to complement-mediated killing and that interaction with IgG contributes to serum resistance. Our findings position APRc as a novel Ig-binding protein and a novel moonlighting immune evasion factor of Rickettsia, contributing to the arsenal of virulence factors utilized by these intracellular pathogens to aid in host colonization.
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6
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Dahmani M, Cook JH, Zhu JC, Riley SP. Contribution of classical complement activation and IgM to the control of Rickettsia infection. Mol Microbiol 2021; 116:1476-1488. [PMID: 34725868 PMCID: PMC8955150 DOI: 10.1111/mmi.14839] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 10/28/2021] [Accepted: 10/29/2021] [Indexed: 01/02/2023]
Abstract
Pathogenic Rickettsia are obligate intracellular bacteria and the etiologic agents of many life‐threatening infectious diseases. Due to the serious nature of these infections, it is imperative to both identify the responsive immune sensory pathways and understand the associated immune mechanisms that restrict Rickettsia proliferation. Previous studies have demonstrated that the mammalian complement system is both activated during Rickettsia infection and contributes to the immune response to infection. To further define this component of the mammalian anti‐Rickettsia immune response, we sought to identify the mechanism(s) of complement activation during Rickettsia infection. We have employed a series of in vitro and in vivo models of infection to investigate the role of the classical complement activation pathway during Rickettsia infection. Depletion or elimination of complement activity demonstrates that both C1q and pre‐existing IgM contribute to complement activation; thus implicating the classical complement system in Rickettsia‐mediated complement activation. Elimination of the classical complement pathway from mice increases susceptibility to R. australis infection with both increased bacterial loads in multiple tissues and decreased immune activation markers. This study highlights the role of the classical complement pathway in immunity against Rickettsia and implicates resident Rickettsia‐responsive IgM in the response to infection.
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Affiliation(s)
- Mustapha Dahmani
- Department of Veterinary Medicine, University of Maryland-College Park, College Park, Maryland, USA.,Virginia-Maryland College of Veterinary Medicine, College Park, Maryland, USA
| | - Jack H Cook
- Department of Veterinary Medicine, University of Maryland-College Park, College Park, Maryland, USA.,Virginia-Maryland College of Veterinary Medicine, College Park, Maryland, USA
| | - Jinyi C Zhu
- Department of Veterinary Medicine, University of Maryland-College Park, College Park, Maryland, USA.,Virginia-Maryland College of Veterinary Medicine, College Park, Maryland, USA
| | - Sean P Riley
- Department of Veterinary Medicine, University of Maryland-College Park, College Park, Maryland, USA.,Virginia-Maryland College of Veterinary Medicine, College Park, Maryland, USA
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7
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Yen WY, Stern K, Mishra S, Helminiak L, Sanchez-Vicente S, Kim HK. Virulence potential of Rickettsia amblyommatis for spotted fever pathogenesis in mice. Pathog Dis 2021; 79:ftab024. [PMID: 33908603 PMCID: PMC8110513 DOI: 10.1093/femspd/ftab024] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 04/15/2021] [Indexed: 11/14/2022] Open
Abstract
Rickettsia amblyommatis belongs to the spotted fever group of Rickettsia and infects Amblyomma americanum (Lone Star ticks) for transmission to offspring and mammals. Historically, the geographic range of A. americanum was restricted to the southeastern USA. However, recent tick surveys identified the progressive northward invasion of A. americanum, contributing to the increased number of patients with febrile illnesses of unknown etiology after a tick bite in the northeastern USA. While serological evidence strongly suggests that patients are infected with R. amblyommatis, the virulence potential of R. amblyommatis is not well established. Here, we performed a bioinformatic analysis of three genome sequences of R. amblyommatis and identified the presence of multiple putative virulence genes whose products are implicated for spotted fever pathogenesis. Similar to other pathogenic spotted fever rickettsiae, R. amblyommatis replicated intracellularly within the cytoplasm of tissue culture cells. Interestingly, R. amblyommatis displayed defective attachment to microvascular endothelial cells. The attachment defect and slow growth rate of R. amblyommatis required relatively high intravenous infectious doses to produce dose-dependent morbidity and mortality in C3H mice. In summary, our results corroborate clinical evidence that R. amblyommatis can cause mild disease manifestation in some patients.
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Affiliation(s)
- Wan-Yi Yen
- Division of Laboratory Animal Resources, Laboratory of Comparative Medicine, Stony Brook University, Stony Brook, NY 11794, USA
| | - Kayla Stern
- John F. Kennedy High School, Bellmore, NY 11710, USA
| | - Smruti Mishra
- Center for Infectious Diseases, Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Luke Helminiak
- Center for Infectious Diseases, Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Santiago Sanchez-Vicente
- Center for Infectious Diseases, Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Hwan Keun Kim
- Center for Infectious Diseases, Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY 11794, USA
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8
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Kristof MN, Allen PE, Yutzy LD, Thibodaux B, Paddock CD, Martinez JJ. Significant Growth by Rickettsia Species within Human Macrophage-Like Cells Is a Phenotype Correlated with the Ability to Cause Disease in Mammals. Pathogens 2021; 10:pathogens10020228. [PMID: 33669499 PMCID: PMC7934685 DOI: 10.3390/pathogens10020228] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 02/09/2021] [Accepted: 02/16/2021] [Indexed: 11/16/2022] Open
Abstract
Rickettsia are significant sources of tick-borne diseases in humans worldwide. In North America, two species in the spotted fever group of Rickettsia have been conclusively associated with disease of humans: Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever, and Rickettsia parkeri, the cause of R. parkeri rickettsiosis. Previous work in our lab demonstrated non-endothelial parasitism by another pathogenic SFG Rickettsia species, Rickettsia conorii, within THP-1-derived macrophages, and we have hypothesized that this growth characteristic may be an underappreciated aspect of rickettsial pathogenesis in mammalian hosts. In this work, we demonstrated that multiple other recognized human pathogenic species of Rickettsia, including R. rickettsii, R. parkeri, Rickettsia africae, and Rickettsiaakari can grow within target endothelial cells as well as within PMA-differentiated THP-1 cells. In contrast, Rickettsia bellii, a Rickettsia species not associated with disease of humans, and R. rickettsii strain Iowa, an avirulent derivative of pathogenic R. rickettsii, could invade both cell types but proliferate only within endothelial cells. Further analysis revealed that similar to previous studies on R. conorii, other recognized pathogenic Rickettsia species could grow within the cytosol of THP-1-derived macrophages and avoided localization with two different markers of lysosomal compartments; LAMP-2 and cathepsin D. R. bellii, on the other hand, demonstrated significant co-localization with lysosomal compartments. Collectively, these findings suggest that the ability of pathogenic rickettsial species to establish a niche within macrophage-like cells could be an important factor in their ability to cause disease in mammals. These findings also suggest that analysis of growth within mammalian phagocytic cells may be useful to predict the pathogenic potential of newly isolated and identified Rickettsia species.
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Affiliation(s)
- M. Nathan Kristof
- Vector Borne Disease Laboratories, Department of Pathobiological Sciences, LSU School of Veterinary Medicine, Baton Rouge, LA 70803, USA; (M.N.K.); (P.E.A.); (L.D.Y.); (B.T.)
| | - Paige E. Allen
- Vector Borne Disease Laboratories, Department of Pathobiological Sciences, LSU School of Veterinary Medicine, Baton Rouge, LA 70803, USA; (M.N.K.); (P.E.A.); (L.D.Y.); (B.T.)
| | - Lane D. Yutzy
- Vector Borne Disease Laboratories, Department of Pathobiological Sciences, LSU School of Veterinary Medicine, Baton Rouge, LA 70803, USA; (M.N.K.); (P.E.A.); (L.D.Y.); (B.T.)
| | - Brandon Thibodaux
- Vector Borne Disease Laboratories, Department of Pathobiological Sciences, LSU School of Veterinary Medicine, Baton Rouge, LA 70803, USA; (M.N.K.); (P.E.A.); (L.D.Y.); (B.T.)
| | - Christopher D. Paddock
- Rickettsial Zoonoses Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, U.S. Department of Health and Human Services, Atlanta, GA 30329, USA;
| | - Juan J. Martinez
- Vector Borne Disease Laboratories, Department of Pathobiological Sciences, LSU School of Veterinary Medicine, Baton Rouge, LA 70803, USA; (M.N.K.); (P.E.A.); (L.D.Y.); (B.T.)
- Correspondence: ; Tel.: +1-225-578-9297
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9
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More than a Pore: Nonlytic Antimicrobial Functions of Complement and Bacterial Strategies for Evasion. Microbiol Mol Biol Rev 2021; 85:85/1/e00177-20. [PMID: 33504655 DOI: 10.1128/mmbr.00177-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The complement system is an evolutionarily ancient defense mechanism against foreign substances. Consisting of three proteolytic activation pathways, complement converges on a common effector cascade terminating in the formation of a lytic pore on the target surface. The classical and lectin pathways are initiated by pattern recognition molecules binding to specific ligands, while the alternative pathway is constitutively active at low levels in circulation. Complement-mediated killing is essential for defense against many Gram-negative bacterial pathogens, and genetic deficiencies in complement can render individuals highly susceptible to infection, for example, invasive meningococcal disease. In contrast, Gram-positive bacteria are inherently resistant to the direct bactericidal activity of complement due to their thick layer of cell wall peptidoglycan. However, complement also serves diverse roles in immune defense against all bacteria by flagging them for opsonization and killing by professional phagocytes, synergizing with neutrophils, modulating inflammatory responses, regulating T cell development, and cross talk with coagulation cascades. In this review, we discuss newly appreciated roles for complement beyond direct membrane lysis, incorporate nonlytic roles of complement into immunological paradigms of host-pathogen interactions, and identify bacterial strategies for complement evasion.
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10
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Ding M, Fan J, Wang W, Wang H, Liu H. Molecular characterization, expression and antimicrobial activity of complement factor D in Megalobrama amblycephala. FISH & SHELLFISH IMMUNOLOGY 2019; 89:43-51. [PMID: 30890434 DOI: 10.1016/j.fsi.2019.03.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 02/23/2019] [Accepted: 03/12/2019] [Indexed: 06/09/2023]
Abstract
Complement factor D (Df) is a serine protease, which can activate the alternative pathway by cleaving complement factor B, and involves in the innate defense against pathogens infection in teleost. In this study, we cloned, characterized the Df gene from blunt snout bream (Megalobrama amblycephala) (Mamdf), and examined its expression pattern and antimicrobial activity. The open reading frame (ORF) of Mamdf was 753 bp, encoding 250 amino acids with a molecular mass of 27.2 kDa. Mamdf consisted of a single serine protease trypsin superfamily domain, 3 substrate binding sites and 3 active sites, but no potential N-glycosylation site. Pairwise alignment showed that Mamdf shared the highest identity (94%) with grass carp (Ctenopharyngodon idellus). Phylogenetic analysis indicated that Mamdf and other vertebrate Df had a common ancestral origin. Mamdf structured with 4 introns and 5 exons. The Mamdf mRNA expressed relatively high at the intestine appearance stage during early development and constitutively expressed in various tissues with the highest expression in the kidney in healthy adults. After challenged with Aeromonas hydrophila, significant changes of Mamdf at both mRNA and protein levels in the kidney, spleen, liver and head-kidney were observed. The recombinant Mamdf protein showed antimicrobial activity against both gram-positive bacteria and gram-negative bacteria. The above results suggested the immune function of Mamdf, and would benefit further detailed Df function research in the immune process in teleost.
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Affiliation(s)
- Ming Ding
- College of Fisheries, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, Huazhong Agricultural University, Wuhan, 430070, China
| | - Jun Fan
- College of Fisheries, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, Huazhong Agricultural University, Wuhan, 430070, China
| | - Weimin Wang
- College of Fisheries, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, Huazhong Agricultural University, Wuhan, 430070, China
| | - Huanling Wang
- College of Fisheries, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, Huazhong Agricultural University, Wuhan, 430070, China
| | - Hong Liu
- College of Fisheries, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, Huazhong Agricultural University, Wuhan, 430070, China.
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