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Barthelemy J, Bogard G, Wolowczuk I. Beyond energy balance regulation: The underestimated role of adipose tissues in host defense against pathogens. Front Immunol 2023; 14:1083191. [PMID: 36936928 PMCID: PMC10019896 DOI: 10.3389/fimmu.2023.1083191] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 01/09/2023] [Indexed: 03/06/2023] Open
Abstract
Although the adipose tissue (AT) is a central metabolic organ in the regulation of whole-body energy homeostasis, it is also an important endocrine and immunological organ. As an endocrine organ, AT secretes a variety of bioactive peptides known as adipokines - some of which have inflammatory and immunoregulatory properties. As an immunological organ, AT contains a broad spectrum of innate and adaptive immune cells that have mostly been studied in the context of obesity. However, overwhelming evidence supports the notion that AT is a genuine immunological effector site, which contains all cell subsets required to induce and generate specific and effective immune responses against pathogens. Indeed, AT was reported to be an immune reservoir in the host's response to infection, and a site of parasitic, bacterial and viral infections. In addition, besides AT's immune cells, preadipocytes and adipocytes were shown to express innate immune receptors, and adipocytes were reported as antigen-presenting cells to regulate T-cell-mediated adaptive immunity. Here we review the current knowledge on the role of AT and AT's immune system in host defense against pathogens. First, we will summarize the main characteristics of AT: type, distribution, function, and extraordinary plasticity. Second, we will describe the intimate contact AT has with lymph nodes and vessels, and AT immune cell composition. Finally, we will present a comprehensive and up-to-date overview of the current research on the contribution of AT to host defense against pathogens, including the respiratory viruses influenza and SARS-CoV-2.
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Affiliation(s)
| | | | - Isabelle Wolowczuk
- Univ. Lille, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (Inserm), Centre Hospitalier Universitaire de Lille (CHU Lille), Institut Pasteur de Lille, U1019 - UMR 9017 - Center for Infection and Immunity of Lille (CIIL), Lille, France
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2
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Grabner GF, Xie H, Schweiger M, Zechner R. Lipolysis: cellular mechanisms for lipid mobilization from fat stores. Nat Metab 2021; 3:1445-1465. [PMID: 34799702 DOI: 10.1038/s42255-021-00493-6] [Citation(s) in RCA: 221] [Impact Index Per Article: 73.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 10/15/2021] [Indexed: 12/13/2022]
Abstract
The perception that intracellular lipolysis is a straightforward process that releases fatty acids from fat stores in adipose tissue to generate energy has experienced major revisions over the last two decades. The discovery of new lipolytic enzymes and coregulators, the demonstration that lipophagy and lysosomal lipolysis contribute to the degradation of cellular lipid stores and the characterization of numerous factors and signalling pathways that regulate lipid hydrolysis on transcriptional and post-transcriptional levels have revolutionized our understanding of lipolysis. In this review, we focus on the mechanisms that facilitate intracellular fatty-acid mobilization, drawing on canonical and noncanonical enzymatic pathways. We summarize how intracellular lipolysis affects lipid-mediated signalling, metabolic regulation and energy homeostasis in multiple organs. Finally, we examine how these processes affect pathogenesis and how lipolysis may be targeted to potentially prevent or treat various diseases.
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Affiliation(s)
- Gernot F Grabner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Hao Xie
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Martina Schweiger
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.
- BioTechMed-Graz, Graz, Austria.
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.
- BioTechMed-Graz, Graz, Austria.
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3
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McGinn J, Lamason RL. The enigmatic biology of rickettsiae: recent advances, open questions and outlook. Pathog Dis 2021; 79:ftab019. [PMID: 33784388 PMCID: PMC8035066 DOI: 10.1093/femspd/ftab019] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [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: 03/26/2021] [Indexed: 02/05/2023] Open
Abstract
Rickettsiae are obligate intracellular bacteria that can cause life-threatening illnesses and are among the oldest known vector-borne pathogens. Members of this genus are extraordinarily diverse and exhibit a broad host range. To establish intracellular infection, Rickettsia species undergo complex, multistep life cycles that are encoded by heavily streamlined genomes. As a result of reductive genome evolution, rickettsiae are exquisitely tailored to their host cell environment but cannot survive extracellularly. This host-cell dependence makes for a compelling system to uncover novel host-pathogen biology, but it has also hindered experimental progress. Consequently, the molecular details of rickettsial biology and pathogenesis remain poorly understood. With recent advances in molecular biology and genetics, the field is poised to start unraveling the molecular mechanisms of these host-pathogen interactions. Here, we review recent discoveries that have shed light on key aspects of rickettsial biology. These studies have revealed that rickettsiae subvert host cells using mechanisms that are distinct from other better-studied pathogens, underscoring the great potential of the Rickettsia genus for revealing novel biology. We also highlight several open questions as promising areas for future study and discuss the path toward solving the fundamental mysteries of this neglected and emerging human pathogen.
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Affiliation(s)
- Jon McGinn
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States
| | - Rebecca L Lamason
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States
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4
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González-Espinoza G, Arce-Gorvel V, Mémet S, Gorvel JP. Brucella: Reservoirs and Niches in Animals and Humans. Pathogens 2021; 10:pathogens10020186. [PMID: 33572264 PMCID: PMC7915599 DOI: 10.3390/pathogens10020186] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 02/02/2021] [Accepted: 02/05/2021] [Indexed: 01/18/2023] Open
Abstract
Brucella is an intracellular bacterium that causes abortion, reproduction failure in livestock and leads to a debilitating flu-like illness with serious chronic complications if untreated in humans. As a successful intracellular pathogen, Brucella has developed strategies to avoid recognition by the immune system of the host and promote its survival and replication. In vivo, Brucellae reside mostly within phagocytes and other cells including trophoblasts, where they establish a preferred replicative niche inside the endoplasmic reticulum. This process is central as it gives Brucella the ability to maintain replicating-surviving cycles for long periods of time, even at low bacterial numbers, in its cellular niches. In this review, we propose that Brucella takes advantage of the environment provided by the cellular niches in which it resides to generate reservoirs and disseminate to other organs. We will discuss how the favored cellular niches for Brucella infection in the host give rise to anatomical reservoirs that may lead to chronic infections or persistence in asymptomatic subjects, and which may be considered as a threat for further contamination. A special emphasis will be put on bone marrow, lymph nodes, reproductive and for the first time adipose tissues, as well as wildlife reservoirs.
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5
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Abstract
There is no updated information on the spread of Rickettsiales in Italy. The purpose of our study is to take stock of the situation on Rickettsiales in Italy by focusing attention on the species identified by molecular methods in humans, in bloodsucking arthropods that could potentially attack humans, and in animals, possible hosts of these Rickettsiales. A computerized search without language restriction was conducted using PubMed updated as of December 31, 2020. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology was followed. Overall, 36 species of microorganisms belonging to Rickettsiales were found. The only species identified in human tissues were Anaplasma phagocytophilum,Rickettsia conorii, R. conorii subsp. israelensis, R. monacensis, R. massiliae, and R. slovaca. Microorganisms transmissible by bloodsucking arthropods could cause humans pathologies not yet well characterized. It should become routine to study the pathogens present in ticks that have bitten a man and at the same time that molecular studies for the search for Rickettsiales can be performed routinely in people who have suffered bites from bloodsucking arthropods.
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6
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Abstract
Over the last decades, rickettsioses are emerging worldwide. These diseases are caused by intracellular bacteria. Although rickettsioses can be treated with antibiotics, a vaccine against rickettsiae is highly desired for several reasons. Rickettsioses are highly prevalent, especially in poor countries, and there are indications of the development of antibiotic resistance. In addition, some rickettsiae can persist and cause recurrent disease. The development of a vaccine requires the understanding of the immune mechanisms that are involved in protection as well as in immunopathology. Knowledge about these immune responses is accumulating, and efforts have been undertaken to identify antigenic components of rickettsiae that may be useful as a vaccine. This review provides an overview on current knowledge of adaptive immunity against rickettsiae, which is essential for defense, rickettsial antigens that have been identified so far, and on vaccination strategies that have been used in animal models of rickettsial infections.
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7
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Kruglikov IL, Shah M, Scherer PE. Obesity and diabetes as comorbidities for COVID-19: Underlying mechanisms and the role of viral-bacterial interactions. eLife 2020; 9:e61330. [PMID: 32930095 PMCID: PMC7492082 DOI: 10.7554/elife.61330] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 08/26/2020] [Indexed: 02/06/2023] Open
Abstract
Obesity and diabetes are established comorbidities for COVID-19. Adipose tissue demonstrates high expression of ACE2 which SARS- CoV-2 exploits to enter host cells. This makes adipose tissue a reservoir for SARS-CoV-2 viruses and thus increases the integral viral load. Acute viral infection results in ACE2 downregulation. This relative deficiency can lead to disturbances in other systems controlled by ACE2, including the renin-angiotensin system. This will be further increased in the case of pre-conditions with already compromised functioning of these systems, such as in patients with obesity and diabetes. Here, we propose that interactions of virally-induced ACE2 deficiency with obesity and/or diabetes leads to a synergistic further impairment of endothelial and gut barrier function. The appearance of bacteria and/or their products in the lungs of obese and diabetic patients promotes interactions between viral and bacterial pathogens, resulting in a more severe lung injury in COVID-19.
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Affiliation(s)
| | - Manasi Shah
- Division of Endocrinology, University of Texas Southwestern Medical CenterDallasUnited States
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical CenterDallasUnited States
| | - Philipp E Scherer
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical CenterDallasUnited States
- Department of Cell Biology, University of Texas Southwestern Medical CenterDallasUnited States
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8
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Mezouar S, Lepidi H, Omar Osman I, Gorvel JP, Raoult D, Mege JL, Bechah Y. T-Bet Controls Susceptibility of Mice to Coxiella burnetii Infection. Front Microbiol 2020; 11:1546. [PMID: 32765448 PMCID: PMC7381240 DOI: 10.3389/fmicb.2020.01546] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 06/15/2020] [Indexed: 01/13/2023] Open
Abstract
T-bet is a transcription factor known to initiate and coordinate the gene expression program during Th1 differentiation, which is crucial for clearance of intracellular pathogens. Q fever is a worldwide zoonosis caused by Coxiella burnetii. This bacterium is transmitted to humans by aerosol. Indeed, the inhibition of the Coxiella-specific adaptive Th1 immune response leads to persistent infection and organ injury. How deficiency of T-bet affects host infection by C. burnetii has not been investigated. Here, using mice with a deletion of the T-bet gene and an airborne mode of infection to reproduce the natural conditions of C. burnetii infection, we show that infected T-bet–/– mice were more affected than wild-type mice. The lack of T-bet leads to defective bacterial control, intense replication, persistent infection, and organ injury manifesting as an increased number of granulomas. The absence of T-bet was also associated with an impaired immune response. Indeed, the production of the immunomodulatory cytokines interleukin (IL)-6 and IL-10 was increased, whereas the expression of microbicidal genes by splenocytes was impaired. Moreover, the absence of T-bet exhibited impaired production of interferon-γ, the principal cytokine released by Th1 effector cells. Thus, our study highlights the key role of T-bet in the control of C. burnetii infection in mice and leads to a reappraisal of granulomas in the pathogenesis of Q fever disease.
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Affiliation(s)
- Soraya Mezouar
- IRD, AP-HM, MEPHI, Aix-Marseille University, Marseille, France.,IHU-Méditerranée Infection, Marseille, France
| | - Hubert Lepidi
- IRD, AP-HM, MEPHI, Aix-Marseille University, Marseille, France.,IHU-Méditerranée Infection, Marseille, France
| | - Ikram Omar Osman
- IRD, AP-HM, MEPHI, Aix-Marseille University, Marseille, France.,IHU-Méditerranée Infection, Marseille, France
| | | | - Didier Raoult
- IRD, AP-HM, MEPHI, Aix-Marseille University, Marseille, France.,IHU-Méditerranée Infection, Marseille, France
| | - Jean-Louis Mege
- IRD, AP-HM, MEPHI, Aix-Marseille University, Marseille, France.,IHU-Méditerranée Infection, Marseille, France.,AP-HM, IHU-Méditerranée Infection, UF Immunologie, Marseille, France
| | - Yassina Bechah
- IHU-Méditerranée Infection, Marseille, France.,IRD, AP-HM, VITROME, Aix-Marseille University, Marseille, France.,INSERM, Marseille, France
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9
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Walenna NF, Kurihara Y, Chou B, Ishii K, Soejima T, Hiromatsu K. Chlamydia pneumoniae infection-induced endoplasmic reticulum stress causes fatty acid-binding protein 4 secretion in murine adipocytes. J Biol Chem 2020; 295:2713-2723. [PMID: 31992597 DOI: 10.1074/jbc.ra119.010683] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 01/23/2020] [Indexed: 12/28/2022] Open
Abstract
Fatty acid-binding protein 4 (FABP4) is predominantly expressed in adipocytes and macrophages and regulates metabolic and inflammatory pathways. FABP4 is secreted from adipocytes during lipolysis, and elevated circulating FABP4 levels are associated with obesity, metabolic disease, and cardiac dysfunction. We previously reported that the bacterial respiratory pathogen Chlamydia pneumoniae infects murine adipocytes and exploits host FABP4 to mobilize fat and replicate within adipocytes. However, whether C. pneumoniae induces FABP4 secretion from adipocytes has not been determined. Here, we show that FABP4 is actively secreted by murine adipocytes upon C. pneumoniae infection. Chemical inhibition of lipase activity and genetic deficiency of hormone-sensitive lipase blocked FABP4 secretion from C. pneumoniae-infected adipocytes. Mechanistically, C. pneumoniae infection induced endoplasmic reticulum (ER) stress and the unfolded protein response (UPR), resulting in elevated levels of mitochondrial reactive oxygen species and cytosolic Ca2+ Of note, exposure to a mitochondrial reactive oxygen species-specific scavenger, MitoTEMPO, reduced FABP4 release from C. pneumoniae-infected adipocytes. Furthermore, treatment with azoramide, which protects cells against ER stress, decreased FABP4 release from C. pneumoniae-infected adipocytes. Using gene silencing of CHOP (C/EBP homologous protein), a central regulator of ER stress, we further validated the role of C. pneumoniae infection-induced ER stress/UPR in promoting FABP4 secretion. Overall, these results indicate that C. pneumoniae infection robustly induces FABP4 secretion from adipocytes by stimulating ER stress/UPR. Our findings shed additional light on the etiological link between C. pneumoniae infection and metabolic syndrome.
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Affiliation(s)
- Nirwana Fitriani Walenna
- Department of Microbiology & Immunology, Fukuoka University Faculty of Medicine, Fukuoka 814-0180, Japan; Department of Bacteriology, Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan
| | - Yusuke Kurihara
- Department of Microbiology & Immunology, Fukuoka University Faculty of Medicine, Fukuoka 814-0180, Japan
| | - Bin Chou
- Department of Microbiology & Immunology, Fukuoka University Faculty of Medicine, Fukuoka 814-0180, Japan
| | - Kazunari Ishii
- Department of Microbiology & Immunology, Fukuoka University Faculty of Medicine, Fukuoka 814-0180, Japan
| | - Toshinori Soejima
- Department of Microbiology & Immunology, Fukuoka University Faculty of Medicine, Fukuoka 814-0180, Japan
| | - Kenji Hiromatsu
- Department of Microbiology & Immunology, Fukuoka University Faculty of Medicine, Fukuoka 814-0180, Japan.
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10
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Bourgeois C, Gorwood J, Barrail-Tran A, Lagathu C, Capeau J, Desjardins D, Le Grand R, Damouche A, Béréziat V, Lambotte O. Specific Biological Features of Adipose Tissue, and Their Impact on HIV Persistence. Front Microbiol 2019; 10:2837. [PMID: 31921023 PMCID: PMC6927940 DOI: 10.3389/fmicb.2019.02837] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 11/22/2019] [Indexed: 12/19/2022] Open
Abstract
Although white AT can contribute to anti-infectious immune responses, it can also be targeted and perturbed by pathogens. The AT's immune involvement is primarily due to strong pro-inflammatory responses (with both local and paracrine effects), and the large number of fat-resident macrophages. Adipocytes also exert direct antimicrobial responses. In recent years, it has been found that memory T cells accumulate in AT, where they provide efficient secondary responses against viral pathogens. These observations have prompted researchers to re-evaluate the links between obesity and susceptibility to infections. In contrast, AT serves as a reservoir for several persistence pathogens, such as human adenovirus Ad-36, Trypanosoma gondii, Mycobacterium tuberculosis, influenza A virus, and cytomegalovirus (CMV). The presence and persistence of bacterial DNA in AT has led to the concept of a tissue-specific microbiota. The unexpected coexistence of immune cells and pathogens within the specific AT environment is intriguing, and its impact on anti-infectious immune responses requires further evaluation. AT has been recently identified as a site of HIV persistence. In the context of HIV infection, AT is targeted by both the virus and the antiretroviral drugs. AT's intrinsic metabolic features, large overall mass, and wide distribution make it a major tissue reservoir, and one that may contribute to the pathophysiology of chronic HIV infections. Here, we review the immune, metabolic, viral, and pharmacological aspects that contribute to HIV persistence in AT. We also evaluate the respective impacts of both intrinsic and HIV-induced factors on AT's involvement as a viral reservoir. Lastly, we examine the potential consequences of HIV persistence on the metabolic and immune activities of AT.
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Affiliation(s)
- Christine Bourgeois
- Center for Immunology of Viral Infections and Autoimmune Diseases, IDMIT Department, IBFJ, CEA, Université Paris Sud, INSERM U1184, Fontenay-aux-Roses, France
| | - Jennifer Gorwood
- INSERM UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-Métabolisme et Nutrition (ICAN), Sorbonne Université, Paris, France
| | - Aurélie Barrail-Tran
- Center for Immunology of Viral Infections and Autoimmune Diseases, IDMIT Department, IBFJ, CEA, Université Paris Sud, INSERM U1184, Fontenay-aux-Roses, France
- AP-HP, Service de Médecine Interne et Immunologie Clinique, Hôpital Bicêtre, Groupe Hospitalier Universitaire Paris Sud, Le Kremlin-Bicêtre, France
| | - Claire Lagathu
- INSERM UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-Métabolisme et Nutrition (ICAN), Sorbonne Université, Paris, France
| | - Jacqueline Capeau
- INSERM UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-Métabolisme et Nutrition (ICAN), Sorbonne Université, Paris, France
| | - Delphine Desjardins
- Center for Immunology of Viral Infections and Autoimmune Diseases, IDMIT Department, IBFJ, CEA, Université Paris Sud, INSERM U1184, Fontenay-aux-Roses, France
| | - Roger Le Grand
- Center for Immunology of Viral Infections and Autoimmune Diseases, IDMIT Department, IBFJ, CEA, Université Paris Sud, INSERM U1184, Fontenay-aux-Roses, France
| | - Abderaouf Damouche
- Center for Immunology of Viral Infections and Autoimmune Diseases, IDMIT Department, IBFJ, CEA, Université Paris Sud, INSERM U1184, Fontenay-aux-Roses, France
| | - Véronique Béréziat
- INSERM UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-Métabolisme et Nutrition (ICAN), Sorbonne Université, Paris, France
| | - Olivier Lambotte
- Center for Immunology of Viral Infections and Autoimmune Diseases, IDMIT Department, IBFJ, CEA, Université Paris Sud, INSERM U1184, Fontenay-aux-Roses, France
- AP-HP, Service de Médecine Interne et Immunologie Clinique, Hôpital Bicêtre, Groupe Hospitalier Universitaire Paris Sud, Le Kremlin-Bicêtre, France
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11
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Abstract
PURPOSE OF REVIEW The purpose of this review is to examine the evidence describing adipose tissue as a reservoir for HIV-1 and how this often expansive anatomic compartment contributes to HIV persistence. RECENT FINDINGS Memory CD4 T cells and macrophages, the major host cells for HIV, accumulate in adipose tissue during HIV/SIV infection of humans and rhesus macaques. Whereas HIV and SIV proviral DNA is detectable in CD4 T cells of multiple fat depots in virtually all infected humans and monkeys examined, viral RNA is less frequently detected, and infected macrophages may be less prevalent in adipose tissue. However, based on viral outgrowth assays, adipose-resident CD4 T cells are latently infected with virus that is replication-competent and infectious. Additionally, adipocytes interact with CD4 T cells and macrophages to promote immune cell activation and inflammation which may be supportive for HIV persistence. Antiviral effector cells, such as CD8 T cells and NK/NKT cells, are abundant in adipose tissue during HIV/SIV infection and typically exceed CD4 T cells, whereas B cells are largely absent from adipose tissue of humans and monkeys. Additionally, CD8 T cells in adipose tissue of HIV patients are activated and have a late differentiated phenotype, with unique TCR clonotypes of less diversity relative to blood CD8 T cells. With respect to the distribution of antiretroviral drugs in adipose tissue, data is limited, but there may be class-specific penetration of fat depots. The trafficking of infected immune cells within adipose tissues is a common event during HIV/SIV infection of humans and monkeys, but the virus may be mostly transcriptionally dormant. Viral replication may occur less in adipose tissue compared to other major reservoirs, such as lymphoid tissue, but replication competence and infectiousness of adipose latent virus are comparable to other tissues. Due to the ubiquitous nature of adipose tissue, inflammatory interactions among adipocytes and CD4 T cells and macrophages, and selective distribution of antiretroviral drugs, the sequestration of infected immune cells within fat depots likely represents a major challenge for cure efforts.
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Affiliation(s)
- Jacob Couturier
- Division of Infectious Diseases, Department of Internal Medicine, The University of Texas Health Science Center at Houston, 6431 Fannin St., MSB 2.112, Houston, TX, 77030, USA
| | - Dorothy E Lewis
- Division of Infectious Diseases, Department of Internal Medicine, The University of Texas Health Science Center at Houston, 6431 Fannin St., MSB 2.112, Houston, TX, 77030, USA.
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12
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Melenotte C, Drancourt M, Gorvel JP, Mège JL, Raoult D. Post-bacterial infection chronic fatigue syndrome is not a latent infection. Med Mal Infect 2019; 49:140-149. [DOI: 10.1016/j.medmal.2019.01.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 01/15/2019] [Indexed: 01/20/2023]
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13
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Lin Y, Leung G, Louie D, Bogoslowski A, Ross J, Kubes P, von der Weid PY, Liao S. Perinodal Adipose Tissue Participates in Immune Protection through a Lymphatic Vessel-Independent Route. THE JOURNAL OF IMMUNOLOGY 2018; 201:296-305. [PMID: 29760196 DOI: 10.4049/jimmunol.1800151] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 04/27/2018] [Indexed: 12/15/2022]
Abstract
Lymphatic vessels remove and transport excess interstitial fluid to lymph nodes (LNs) for fluid balance and immune protection. LNs are typically surrounded by perinodal adipose tissue (PAT). However, PAT is a blood vessel-rich but lymphatic-rare tissue; therefore, how excess fluid in PAT is removed remains unclear. Using C57BL/6 mice, fluorescent dye tracing and transmission electron microscopy results suggest that fluid in PAT can travel to the LN via collagen I+ channels (PAT-LN conduits), merge into a collagen-rich space between the PAT and LN capsule (PAT-LN sinus), and may enter the LN via the LN capsule-associated conduits. This newly identified route of fluid flow allows fluid to enter the draining LN even when the afferent lymphatic vessels are blocked, indicating that fluid trafficking in PAT-LN conduits is not dependent on functional lymphatic vessels. Similar to lymphatic vessels, PAT-LN conduits can deliver Ags to the LN for immune protection. Additionally, Staphylococcus aureus from intradermal or i.v. infection may use PAT-LN conduits to infect PAT and stimulate PAT immune protection. Our studies revealed a new route of material exchange between PAT and the LN. Ag accumulation and bacterial infection in PAT demonstrate that PAT not only provides energy and regulatory factors, but can also directly participate in immune protection, indicating a new immune function of PAT for host immunity.
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Affiliation(s)
- Yujia Lin
- Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada.,Department of General Surgery, The Second Affiliated Hospital of Harbin Medical University, Harbin Medical University, Harbin 150086, China; and
| | - Glory Leung
- Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Dante Louie
- Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Ania Bogoslowski
- Department of Physiology and Pharmacology, Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - James Ross
- Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Paul Kubes
- Department of Physiology and Pharmacology, Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Pierre-Yves von der Weid
- Department of Physiology and Pharmacology, Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Shan Liao
- Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada;
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14
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Osterloh A. Immune response against rickettsiae: lessons from murine infection models. Med Microbiol Immunol 2017; 206:403-417. [PMID: 28770333 PMCID: PMC5664416 DOI: 10.1007/s00430-017-0514-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Accepted: 07/20/2017] [Indexed: 12/19/2022]
Abstract
Rickettsiae are small intracellular bacteria that can cause life-threatening febrile diseases. Rickettsioses occur worldwide with increasing incidence. Therefore, a vaccine is highly desired. A prerequisite for the development of a vaccine is the knowledge of the immune response against these bacteria, in particular protective immunity. In recent years murine models of rickettsial infections have been established, and the study of immune response against rickettsiae in mice provided many new insights into protective and pathological immune reactions. This review summarizes the current knowledge about immune mechanisms in protection and pathology in rickettsial infections.
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Affiliation(s)
- Anke Osterloh
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.
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15
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Ayyappan JP, Vinnard C, Subbian S, Nagajyothi JF. Effect of Mycobacterium tuberculosis infection on adipocyte physiology. Microbes Infect 2017; 20:81-88. [PMID: 29109018 DOI: 10.1016/j.micinf.2017.10.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 10/24/2017] [Accepted: 10/26/2017] [Indexed: 12/12/2022]
Abstract
Tuberculosis (TB) remains as a major threat to human health worldwide despite of the availability of standardized antibiotic therapy. One of the characteristic of pathogenic Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis is its ability to persist in the host in a dormant state and develop latent infection without clinical signs of active disease. However, the mechanisms involved in bacterial persistence and the establishment of latency is not well understood. Adipose tissue is emerging as an important niche that favors actively replicating as well as dormant Mtb during acute and latent infection. This also suggests that Mtb can disseminate from the lungs to adipose tissue during aerosol infection and/or from adipose tissue to lungs during reactivation of latent infection. In this study, we report the interplay between key adipokine levels and the dynamics of Mtb pathogenesis in the lungs and adipose tissue using a rabbit model of pulmonary infection with two clinical isolates that produce divergent outcome in disease progression. Results show that markers of adipocyte physiology and function were significantly altered during Mtb infection and distinct patterns of adipokine expression were noted between adipose tissue and the lungs. Moreover, these markers were differentially expressed between active disease and latent infection. Thus, this study highlights the importance of targeting adipocyte function as potential target for developing better TB intervention strategies.
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Affiliation(s)
- Janeesh Plakkal Ayyappan
- Department of Microbiology, Biochemistry and Molecular Genetics, Public Health Research Institute, New Jersey Medical School, Newark, USA
| | - Christopher Vinnard
- Department of Medicine, Public Health Research Institute, New Jersey Medical School, Newark, USA
| | - Selvakumar Subbian
- Department of Medicine, Public Health Research Institute, New Jersey Medical School, Newark, USA.
| | - Jyothi F Nagajyothi
- Department of Microbiology, Biochemistry and Molecular Genetics, Public Health Research Institute, New Jersey Medical School, Newark, USA.
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16
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Walenna NF, Kurihara Y, Chou B, Ishii K, Soejima T, Itoh R, Shimizu A, Ichinohe T, Hiromatsu K. Chlamydia pneumoniae exploits adipocyte lipid chaperone FABP4 to facilitate fat mobilization and intracellular growth in murine adipocytes. Biochem Biophys Res Commun 2017; 495:353-359. [PMID: 29108997 DOI: 10.1016/j.bbrc.2017.11.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 11/02/2017] [Indexed: 11/28/2022]
Abstract
Fatty acid-binding protein 4 (FABP4), a cytosolic lipid chaperone predominantly expressed in adipocytes and macrophages, modulates lipid fluxes, trafficking, signaling, and metabolism. Recent studies have demonstrated that FABP4 regulates metabolic and inflammatory pathways, and in mouse models its inhibition can improve type 2 diabetes mellitus and atherosclerosis. However, the role of FABP4 in bacterial infection, metabolic crosstalk between host and pathogen, and bacterial pathogenesis have not been studied. As an obligate intracellular pathogen, Chlamydia pneumoniae needs to obtain nutrients such as ATP and lipids from host cells. Here, we show that C. pneumoniae successfully infects and proliferates in murine adipocytes by inducing hormone sensitive lipase (HSL)-mediated lipolysis. Chemical inhibition or genetic manipulation of HSL significantly abrogated the intracellular growth of C. pneumoniae in adipocytes. Liberated free fatty acids were utilized to generate ATP via β-oxidation, which C. pneumoniae usurped for its replication. Strikingly, chemical inhibition or genetic silencing of FABP4 significantly abrogated C. pneumoniae infection-induced lipolysis and mobilization of liberated FFAs, resulting in reduced bacterial growth in adipocytes. Collectively, these results demonstrate that C. pneumoniae exploits host FABP4 to facilitate fat mobilization and intracellular replication in adipocytes. This work uncovers a novel strategy used by intracellular pathogens for acquiring energy via hijacking of the host lipid metabolism pathway.
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Affiliation(s)
- Nirwana Fitriani Walenna
- Department of Microbiology & Immunology, Faculty of Medicine, Fukuoka University, Fukuoka 814-0180, Japan; Department of Bacteriology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Yusuke Kurihara
- Department of Microbiology & Immunology, Faculty of Medicine, Fukuoka University, Fukuoka 814-0180, Japan
| | - Bin Chou
- Department of Microbiology & Immunology, Faculty of Medicine, Fukuoka University, Fukuoka 814-0180, Japan
| | - Kazunari Ishii
- Department of Microbiology & Immunology, Faculty of Medicine, Fukuoka University, Fukuoka 814-0180, Japan
| | - Toshinori Soejima
- Department of Microbiology & Immunology, Faculty of Medicine, Fukuoka University, Fukuoka 814-0180, Japan
| | - Ryota Itoh
- Department of Microbiology & Immunology, Faculty of Medicine, Fukuoka University, Fukuoka 814-0180, Japan
| | - Akinori Shimizu
- Department of Microbiology & Immunology, Faculty of Medicine, Fukuoka University, Fukuoka 814-0180, Japan
| | - Takeshi Ichinohe
- Division of Viral Infection, International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan
| | - Kenji Hiromatsu
- Department of Microbiology & Immunology, Faculty of Medicine, Fukuoka University, Fukuoka 814-0180, Japan.
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17
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Tanowitz HB, Scherer PE, Mota MM, Figueiredo LM. Adipose Tissue: A Safe Haven for Parasites? Trends Parasitol 2016; 33:276-284. [PMID: 28007406 DOI: 10.1016/j.pt.2016.11.008] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 11/17/2016] [Accepted: 11/28/2016] [Indexed: 12/13/2022]
Abstract
Adipose tissue (AT) is no longer regarded as an inert lipid storage, but as an important central regulator in energy homeostasis and immunity. Three parasite species are uniquely associated with AT during part of their life cycle: Trypanosoma cruzi, the causative agent of Chagas disease; Trypanosoma brucei, the causative agent of African sleeping sickness; and Plasmodium spp., the causative agents of malaria. In AT, T. cruzi resides inside adipocytes, T. brucei is found in the interstitial spaces between adipocytes, while Plasmodium spp. infect red blood cells, which may adhere to the blood vessels supplying AT. Here, we discuss how each parasite species adapts to this tissue environment and what the implications are for pathogenesis, clinical manifestations, and therapy.
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Affiliation(s)
- Herbert B Tanowitz
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Philipp E Scherer
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-8549, USA; Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Maria M Mota
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Luisa M Figueiredo
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal.
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18
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Moderzynski K, Papp S, Rauch J, Heine L, Kuehl S, Richardt U, Fleischer B, Osterloh A. CD4+ T Cells Are as Protective as CD8+ T Cells against Rickettsia typhi Infection by Activating Macrophage Bactericidal Activity. PLoS Negl Trop Dis 2016; 10:e0005089. [PMID: 27875529 PMCID: PMC5119731 DOI: 10.1371/journal.pntd.0005089] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 10/02/2016] [Indexed: 01/07/2023] Open
Abstract
Rickettsia typhi is an intracellular bacterium that causes endemic typhus, a febrile disease that can be fatal due to complications including pneumonia, hepatitis and meningoencephalitis, the latter being a regular outcome in T and B cell-deficient C57BL/6 RAG1-/- mice upon Rickettsia typhi infection. Here, we show that CD4+ TH1 cells that are generated in C57BL/6 mice upon R. typhi infection are as protective as cytotoxic CD8+ T cells. CD4+- as well as CD8+-deficient C57BL/6 survived the infection without showing symptoms of disease at any point in time. Moreover, adoptively transferred CD8+ and CD4+ immune T cells entered the CNS of C57BL/6 RAG1-/- mice with advanced infection and both eradicated the bacteria. However, immune CD4+ T cells protected only approximately 60% of the animals from death. They induced the expression of iNOS in infiltrating macrophages as well as in resident microglia in the CNS which can contribute to bacterial killing but also accelerate pathology. In vitro immune CD4+ T cells inhibited bacterial growth in infected macrophages which was in part mediated by the release of IFNγ. Collectively, our data demonstrate that CD4+ T cells are as protective as CD8+ T cells against R. typhi, provided that CD4+ TH1 effector cells are present in time to support bactericidal activity of phagocytes via the release of IFNγ and other factors. With regard to vaccination against TG Rickettsiae, our findings suggest that the induction of CD4+ TH1 effector cells is sufficient for protection. Endemic typhus caused by Rickettsia typhi usually is a relatively mild disease. However, CNS inflammation and neurological symptoms are complications that can occur in severe cases. This outcome of disease is regularly observed in T and B cell-deficient C57BL/6 RAG1-/- mice upon infection with R. typhi. We show here that CD4+ T cells are as protective as cytotoxic CD8+ T cells against R. typhi as long as they are present in time. This is evidenced by the fact that neither CD8+ nor CD4+ T cell-deficient C57BL/6 mice develop disease which is also true for R. typhi-infected C57BL/6 RAG1-/- mice that receive immune CD8+ or CD4+ at an early point in time. Moreover, adoptive transfer of immune CD4+ T cells still protects approximately 60% of C57BL/6 RAG1-/- mice when applied later in advanced infection when the bacteria start to rise. Although CD8+ T cells are faster and more efficient in bacterial elimination, R. typhi is not detectable in CD4+ T cell recipients anymore. We further show that immune CD4+ T cells activate bactericidal functions of microglia and macrophages in the CNS in vivo and inhibit bacterial growth in infected macrophages in vitro which is in part mediated by the release of IFNγ. Collectively, we demonstrate for the first time that CD4+ T cells alone are sufficient to protect against R. typhi infection. With regard to vaccination our findings suggest that the induction of R. typhi-specific CD4+ TH1 effector T cells may be as effective as the much more difficult targeting of cytotoxic CD8+ T cells.
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Affiliation(s)
- Kristin Moderzynski
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Stefanie Papp
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Jessica Rauch
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Liza Heine
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Svenja Kuehl
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Ulricke Richardt
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Bernhard Fleischer
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Institute for Immunology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Anke Osterloh
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- * E-mail:
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19
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Hauptmann M, Kolbaum J, Lilla S, Wozniak D, Gharaibeh M, Fleischer B, Keller CA. Protective and Pathogenic Roles of CD8+ T Lymphocytes in Murine Orientia tsutsugamushi Infection. PLoS Negl Trop Dis 2016; 10:e0004991. [PMID: 27606708 PMCID: PMC5015871 DOI: 10.1371/journal.pntd.0004991] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 08/19/2016] [Indexed: 01/12/2023] Open
Abstract
T cells are known to contribute to immune protection against scrub typhus, a potentially fatal infection caused by the obligate intracellular bacterium Orientia (O.) tsutsugamushi. However, the contribution of CD8+ T cells to protection and pathogenesis during O. tsutsugamushi infection is still unknown. Using our recently developed BALB/c mouse model that is based on footpad inoculation of the human-pathogenic Karp strain, we show that activated CD8+ T cells infiltrate spleen and lung during the third week of infection. Depletion of CD8+ T cells with monoclonal antibodies resulted in uncontrolled pathogen growth and mortality. Adoptive transfer of CD8+ T cells from infected animals protected naïve BALB/c mice from lethal outcome of intraperitoneal challenge. In C57Bl/6 mice, the pulmonary lymphocyte compartment showed an increased percentage of CD8+ T cells for at least 135 days post O. tsutsugamushi infection. Depletion of CD8+ T cells at 84 days post infection caused reactivation of bacterial growth. In CD8+ T cell-deficient beta 2-microglobulin knockout mice, bacterial replication was uncontrolled, and all mice succumbed to the infection, despite higher serum IFN-γ levels and stronger macrophage responses in liver and lung. Moreover, we show that CD8+ T cells but not NKT cells were required for hepatocyte injury: elevated concentrations of serum alanine aminotransferase and infection-induced subcapsular necrotic liver lesions surrounded by macrophages were found in C57Bl/6 and CD1d-deficient mice, but not in beta 2-microglobulin knockout mice. In the lungs, peribronchial macrophage infiltrations also depended on CD8+ T cells. In summary, our results demonstrate that CD8+ T cells restrict growth of O. tsutsugamushi during acute and persistent infection, and are required to protect from lethal infections in BALB/c and C57BL/6 mice. However, they also elicit specific pathologic tissue lesions in liver and lung.
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Affiliation(s)
- Matthias Hauptmann
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Julia Kolbaum
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Stefanie Lilla
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - David Wozniak
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Mohammad Gharaibeh
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Bernhard Fleischer
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Institute for Immunology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christian A. Keller
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
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20
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Morrot A, Villar SR, González FB, Pérez AR. Evasion and Immuno-Endocrine Regulation in Parasite Infection: Two Sides of the Same Coin in Chagas Disease? Front Microbiol 2016; 7:704. [PMID: 27242726 PMCID: PMC4876113 DOI: 10.3389/fmicb.2016.00704] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 04/28/2016] [Indexed: 12/16/2022] Open
Abstract
Chagas disease is a serious illness caused by the protozoan parasite Trypanosoma cruzi. Nearly 30% of chronically infected people develop cardiac, digestive, or mixed alterations, suggesting a broad range of host-parasite interactions that finally impact upon chronic disease outcome. The ability of T. cruzi to persist and cause pathology seems to depend on diverse factors like T. cruzi strains, the infective load and the route of infection, presence of virulence factors, the parasite capacity to avoid protective immune response, the strength and type of host defense mechanisms and the genetic background of the host. The host-parasite interaction is subject to a constant neuro-endocrine regulation that is thought to influence the adaptive immune system, and as the infection proceeds it can lead to a broad range of outcomes, ranging from pathogen elimination to its continued persistence in the host. In this context, T. cruzi evasion strategies and host defense mechanisms can be envisioned as two sides of the same coin, influencing parasite persistence and different outcomes observed in Chagas disease. Understanding how T. cruzi evade host's innate and adaptive immune response will provide important clues to better dissect mechanisms underlying the pathophysiology of Chagas disease.
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Affiliation(s)
- Alexandre Morrot
- Institute of Microbiology, Federal University of Rio de Janeiro Rio de Janeiro, Brazil
| | - Silvina R Villar
- Institute of Clinical and Experimental Immunology of Rosario, CONICET, National University of RosarioRosario, Argentina; Faculty of Medical Sciences, National University of RosarioRosario, Argentina
| | - Florencia B González
- Institute of Clinical and Experimental Immunology of Rosario, CONICET, National University of RosarioRosario, Argentina; Faculty of Medical Sciences, National University of RosarioRosario, Argentina
| | - Ana R Pérez
- Institute of Clinical and Experimental Immunology of Rosario, CONICET, National University of RosarioRosario, Argentina; Faculty of Medical Sciences, National University of RosarioRosario, Argentina
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21
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Persisting Rickettsia typhi Causes Fatal Central Nervous System Inflammation. Infect Immun 2016; 84:1615-1632. [PMID: 26975992 DOI: 10.1128/iai.00034-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 03/06/2016] [Indexed: 01/03/2023] Open
Abstract
Rickettsioses are emerging febrile diseases caused by obligate intracellular bacteria belonging to the family Rickettsiaceae. Rickettsia typhi belongs to the typhus group (TG) of this family and is the causative agent of endemic typhus, a disease that can be fatal. In the present study, we analyzed the course of R. typhi infection in C57BL/6 RAG1(-/-) mice. Although these mice lack adaptive immunity, they developed only mild and temporary symptoms of disease and survived R. typhi infection for a long period of time. To our surprise, 3 to 4 months after infection, C57BL/6 RAG1(-/-) mice suddenly developed lethal neurological disorders. Analysis of these mice at the time of death revealed high bacterial loads, predominantly in the brain. This was accompanied by a massive expansion of microglia and by neuronal cell death. Furthermore, high numbers of infiltrating CD11b(+) macrophages were detectable in the brain. In contrast to the microglia, these cells harbored R. typhi and showed an inflammatory phenotype, as indicated by inducible nitric oxide synthase (iNOS) expression, which was not observed in the periphery. Having shown that R. typhi persists in immunocompromised mice, we finally asked whether the bacteria are also able to persist in resistant C57BL/6 and BALB/c wild-type mice. Indeed, R. typhi could be recultivated from lung, spleen, and brain tissues from both strains even up to 1 year after infection. This is the first report demonstrating persistence and reappearance of R. typhi, mainly restricted to the central nervous system in immunocompromised mice.
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22
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Mycobacterium tuberculosis
infection of the ‘non‐classical immune cell’. Immunol Cell Biol 2015; 93:789-95. [DOI: 10.1038/icb.2015.43] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 03/02/2015] [Accepted: 03/18/2015] [Indexed: 01/29/2023]
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Abstract
PURPOSE OF REVIEW This review summarizes current knowledge on the contribution of mesenteric adipose tissue in intestinal inflammation. We will describe the cellular and humoral characteristics of creeping fat, their potential impact for Crohn's disease and propose a working model for the critical interplay between the creeping fat and the inflamed intestine. RECENT FINDINGS Creeping fat can be distinguished from healthy adipose tissue by its distinctively small adipocytes, by a specific microenvironment defined by high levels of adipokines and by a dominant immune cell infiltration. In Crohn's disease transmural inflammation facilitates increased bacterial translocation into the creeping fat. Translocalizing antigens can directly activate (pre)adipocytes via innate receptors. Adipocyte-derived mediators modulate phenotype and function of innate and adaptive immune cells. Activated (pre)adipocytes and adipokine-modulated immune cells might support a degree of inflammatory activation within the creeping fat that allows competent immune defense against exogenous factors while preventing systemic inflammation. SUMMARY Fat tissue as an active organ in health and disease has been ignored for too long. The last few years of research provided evidence for the complex metabolic and immunological functions of adipose tissue. On the basis of the available data, creeping fat in Crohn's disease exerts a protective function by a localized anti-inflammatory effect, thus preventing a systemic inflammatory response.
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Adipocytes in both brown and white adipose tissue of adult mice are functionally connected via gap junctions: implications for Chagas disease. Microbes Infect 2014; 16:893-901. [PMID: 25150689 DOI: 10.1016/j.micinf.2014.08.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 07/11/2014] [Accepted: 08/13/2014] [Indexed: 01/30/2023]
Abstract
Adipose tissue serves as a host reservoir for the protozoan Trypanosoma cruzi, the causative organism in Chagas disease. Gap junctions interconnect cells of most tissues, serving to synchronize cell activities including secretion in glandular tissue, and we have previously demonstrated that gap junctions are altered in various tissues and cells infected with T. cruzi. Herein, we examined the gap junction protein connexin 43 (Cx43) expression in infected adipose tissues. Adipose tissue is the largest endocrine organ of the body and is also involved in other physiological functions. In mammals, it is primarily composed of white adipocytes. Although gap junctions are a prominent feature of brown adipocytes, they have not been explored extensively in white adipocytes, especially in the setting of infection. Thus, we examined functional coupling in both white and brown adipocytes in mice. Injection of electrical current or the dye Lucifer Yellow into adipocytes within fat tissue spread to adjacent cells, which was reduced by treatment with agents known to block gap junctions. Moreover, Cx43 was detected in both brown and white fat tissue. At thirty and ninety days post-infection, Cx43 was downregulated in brown adipocytes and upregulated in white adipocytes. Gap junction-mediated intercellular communication likely contributes to hormone secretion and other functions in white adipose tissue and to nonshivering thermogenesis in brown fat, and modulation of the coupling by T. cruzi infection is expected to impact these functions.
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25
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Bechah Y, Verneau J, Ben Amara A, Barry AO, Lépolard C, Achard V, Panicot-Dubois L, Textoris J, Capo C, Ghigo E, Mege JL. Persistence of Coxiella burnetii, the agent of Q fever, in murine adipose tissue. PLoS One 2014; 9:e97503. [PMID: 24835240 PMCID: PMC4023977 DOI: 10.1371/journal.pone.0097503] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 04/17/2014] [Indexed: 12/12/2022] Open
Abstract
Coxiella burnetii, the agent of Q fever, is known to persist in humans and rodents but its cellular reservoir in hosts remains undetermined. We hypothesized that adipose tissue serves as a C. burnetii reservoir during bacterial latency. BALB/c and C57BL/6 mice were infected with C. burnetii by the intraperitoneal route or the intracheal route. Adipose tissue was tested for the presence of C. burnetii several months after infection. C. burnetii was detected in abdominal, inguinal and dorsal adipose tissue 4 months post-infection, when no bacteria were detected in blood, liver, lungs and spleen, regardless of the inoculation route and independently of mouse strain. The transfer of abdominal adipose tissue from convalescent BALB/c mice to naïve immunodeficient mice resulted in the infection of the recipient animals. It is likely that C. burnetii infects adipocytes in vivo because bacteria were found in adipocytes within adipose tissue and replicated within in vitro-differentiated adipocytes. In addition, C. burnetii induced a specific transcriptional program in in-vivo and in vitro-differentiated adipocytes, which was enriched in categories associated with inflammatory response, hormone response and cytoskeleton. These changes may account for bacterial replication in in-vitro and chronic infection in-vivo. Adipose tissue may be the reservoir in which C. burnetii persists for prolonged periods after apparent clinical cure. The mouse model of C. burnetii infection may be used to understand the relapses of Q fever and provide new perspectives to the follow-up of patients.
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Affiliation(s)
- Yassina Bechah
- Unité de Recherche sur les Maladies Infectieuses Transmissibles et Emergentes, Aix-Marseille Université, UMR CNRS 7278, IRD 198, INSERM U1095, Marseille, France
- * E-mail:
| | - Johanna Verneau
- Unité de Recherche sur les Maladies Infectieuses Transmissibles et Emergentes, Aix-Marseille Université, UMR CNRS 7278, IRD 198, INSERM U1095, Marseille, France
| | - Amira Ben Amara
- Unité de Recherche sur les Maladies Infectieuses Transmissibles et Emergentes, Aix-Marseille Université, UMR CNRS 7278, IRD 198, INSERM U1095, Marseille, France
| | - Abdoulaye O. Barry
- Unité de Recherche sur les Maladies Infectieuses Transmissibles et Emergentes, Aix-Marseille Université, UMR CNRS 7278, IRD 198, INSERM U1095, Marseille, France
| | - Catherine Lépolard
- Unité de Recherche sur les Maladies Infectieuses Transmissibles et Emergentes, Aix-Marseille Université, UMR CNRS 7278, IRD 198, INSERM U1095, Marseille, France
| | - Vincent Achard
- Nutrition, Obésité et Risque Thrombotique, Aix-Marseille Université, UMR_S INSERM, Marseille, France
| | - Laurence Panicot-Dubois
- Aix-Marseille Université UMR-S1076, Endothélium, Pathologies Vasculaires et Cibles Thérapeutiques, Marseille, France
| | - Julien Textoris
- Unité de Recherche sur les Maladies Infectieuses Transmissibles et Emergentes, Aix-Marseille Université, UMR CNRS 7278, IRD 198, INSERM U1095, Marseille, France
| | - Christian Capo
- Unité de Recherche sur les Maladies Infectieuses Transmissibles et Emergentes, Aix-Marseille Université, UMR CNRS 7278, IRD 198, INSERM U1095, Marseille, France
| | - Eric Ghigo
- Unité de Recherche sur les Maladies Infectieuses Transmissibles et Emergentes, Aix-Marseille Université, UMR CNRS 7278, IRD 198, INSERM U1095, Marseille, France
| | - Jean-Louis Mege
- Unité de Recherche sur les Maladies Infectieuses Transmissibles et Emergentes, Aix-Marseille Université, UMR CNRS 7278, IRD 198, INSERM U1095, Marseille, France
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26
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Zulian A, Cancello R, Ruocco C, Gentilini D, Di Blasio AM, Danelli P, Micheletto G, Cesana E, Invitti C. Differences in visceral fat and fat bacterial colonization between ulcerative colitis and Crohn's disease. An in vivo and in vitro study. PLoS One 2013; 8:e78495. [PMID: 24205244 PMCID: PMC3813471 DOI: 10.1371/journal.pone.0078495] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 09/13/2013] [Indexed: 11/19/2022] Open
Abstract
Crohn's disease (CD) is notably characterized by the expansion of visceral fat with small adipocytes expressing a high proportion of anti-inflammatory genes. Conversely, visceral fat depots in ulcerative colitis (UC) patients have never been characterized. Our study aims were a) to compare adipocyte morphology and gene expression profile and bacterial translocation in omental (OM) and mesenteric (MES) adipose tissue of patients with UC and CD, and b) to investigate the effect of bacterial infection on adipocyte proliferation in vitro. Specimens of OM and MES were collected from 11 UC and 11 CD patients, processed and examined by light microscopy. Gene expression profiles were evaluated in adipocytes isolated from visceral adipose tissue using microarray and RTqPCR validations. Bacteria within adipose tissue were immuno-detected by confocal scanning laser microscopy. Adipocytes were incubated with Enterococcus faecalis and cells counted after 24 h. Morphology and molecular profile of OM and MES revealed that UC adipose tissue is less inflamed than CD adipose tissue. Genes linked to inflammation, bacterial response, chemotaxis and angiogenesis were down-regulated in adipocytes from UC compared to CD, whereas genes related to metallothioneins, apoptosis pathways and growth factor binding were up-regulated. A dense perinuclear positivity for Enterococcus faecalis was detected in visceral adipocytes from CD, whereas positivity was weak in UC. In vitro bacterial infection was associated with a five-fold increase in the proliferation rate of OM preadipocytes. Compared to UC, visceral adipose tissue from CD is more inflamed and more colonized by intestinal bacteria, which increase adipocyte proliferation. The influence of bacteria stored within adipocytes on the clinical course of IBD warrants further investigations.
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Affiliation(s)
- Alessandra Zulian
- Diabetes Research Laboratory, Istituto Auxologico Italiano, Milan, Italy
| | - Raffaella Cancello
- Laboratory of Molecular Biology, Istituto Auxologico Italiano, Milan, Italy
| | - Chiara Ruocco
- Diabetes Research Laboratory, Istituto Auxologico Italiano, Milan, Italy
| | - Davide Gentilini
- Laboratory of Molecular Biology, Istituto Auxologico Italiano, Milan, Italy
| | | | - Piergiorgio Danelli
- Department of Clinical Sciences, Luigi Sacco Hospital, University of Milan, Milan, Italy
| | - Giancarlo Micheletto
- Department of Medical and Surgical Pathophysiology and Transplants, University of Milan, Milan, Italy
| | | | - Cecilia Invitti
- Department of Medical Sciences and Rehabilitation, Istituto Auxologico Italiano, Milan, Italy
- * E-mail:
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Kumar M, Roe K, Nerurkar PV, Namekar M, Orillo B, Verma S, Nerurkar VR. Impaired virus clearance, compromised immune response and increased mortality in type 2 diabetic mice infected with West Nile virus. PLoS One 2012; 7:e44682. [PMID: 22953001 PMCID: PMC3432127 DOI: 10.1371/journal.pone.0044682] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Accepted: 08/06/2012] [Indexed: 12/13/2022] Open
Abstract
Clinicoepidemiological data suggest that type 2 diabetes is associated with increased risk of West Nile virus encephalitis (WNVE). However, no experimental studies have elucidated the role of diabetes in WNV neuropathogenesis. Herein, we employed the db/db mouse model to understand WNV immunopathogenesis in diabetics. Nine-week old C57BL/6 WT and db/db mice were inoculated with WNV and mortality, virus burden in the periphery and brain, and antiviral defense responses were analyzed. db/db mice were highly susceptible to WNV disease, exhibited increased tissue tropism and mortality than the wild-type mice, and were unable to clear the infection. Increased and sustained WNV replication was observed in the serum, peripheral tissues and brain of db/db mice, and heightened virus replication in the periphery was correlated with enhanced neuroinvasion and replication of WNV in the brain. WNV infection in db/db mice was associated with enhanced inflammatory response and compromised antiviral immune response characterized by delayed induction of IFN-α, and significantly reduced concentrations of WNV-specific IgM and IgG antibodies. The compromised immune response in db/db mice correlated with increased viremia. These data suggest that delayed immune response coupled with failure to clear the virus leads to increased mortality in db/db mice. In conclusion, this study provides unique mechanistic insight into the immunopathogenesis of WNVE observed in diabetics and can be used to develop therapeutics for the management of WNVE among diabetic patients.
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Affiliation(s)
- Mukesh Kumar
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- Pacific Center for Emerging Infectious Diseases Research, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Kelsey Roe
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- Pacific Center for Emerging Infectious Diseases Research, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Pratibha V. Nerurkar
- Laboratory of Metabolic Disorders and Alternative Medicine, Department of Molecular Biosciences and Bioengineering, College of Tropical Agriculture and Human Resources, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Madhuri Namekar
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- Pacific Center for Emerging Infectious Diseases Research, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Beverly Orillo
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- Pacific Center for Emerging Infectious Diseases Research, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Saguna Verma
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- Pacific Center for Emerging Infectious Diseases Research, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Vivek R. Nerurkar
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- Pacific Center for Emerging Infectious Diseases Research, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- * E-mail:
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Faucher JF, Socolovschi C, Aubry C, Chirouze C, Hustache-Mathieu L, Raoult D, Hoen B. Brill-Zinsser disease in Moroccan man, France, 2011. Emerg Infect Dis 2012; 18:171-2. [PMID: 22261378 PMCID: PMC3310116 DOI: 10.3201/eid1801.111057] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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29
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Nagajyothi F, Machado FS, Burleigh BA, Jelicks LA, Scherer PE, Mukherjee S, Lisanti MP, Weiss LM, Garg NJ, Tanowitz HB. Mechanisms of Trypanosoma cruzi persistence in Chagas disease. Cell Microbiol 2012; 14:634-43. [PMID: 22309180 DOI: 10.1111/j.1462-5822.2012.01764.x] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Trypanosoma cruzi infection leads to development of chronic Chagas disease. In this article, we provide an update on the current knowledge of the mechanisms employed by the parasite to gain entry into the host cells and establish persistent infection despite activation of a potent immune response by the host. Recent studies point to a number of T. cruzi molecules that interact with host cell receptors to promote parasite invasion of the diverse host cells. T. cruzi expresses an antioxidant system and thromboxane A(2) to evade phagosomal oxidative assault and suppress the host's ability to clear parasites. Additional studies suggest that besides cardiac and smooth muscle cells that are the major target of T. cruzi infection, adipocytes and adipose tissue serve as reservoirs from where T. cruzi can recrudesce and cause disease decades later. Further, T. cruzi employs at least four strategies to maintain a symbiotic-like relationship with the host, and ensure consistent supply of nutrients for its own survival and long-term persistence. Ongoing and future research will continue to help refining the models of T. cruzi invasion and persistence in diverse tissues and organs in the host.
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Affiliation(s)
- Fnu Nagajyothi
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY, USA
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Amara AB, Bechah Y, Mege JL. Immune response and Coxiella burnetii invasion. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 984:287-98. [PMID: 22711638 DOI: 10.1007/978-94-007-4315-1_15] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Coxiella burnetii, the causative agent of Q fever, has evolved a wealth of mechanisms in order to persist within hosts. Two tissues, namely adipose tissue and placenta, are candidates to house C. burnetii, but the mechanisms governing C. burnetii survival in these tissues are still unknown. In contrast, monocytes and macrophages are well-known targets of C. burnetii. First, C. burnetii has developed a specific strategy of phagocytosis subversion that consists of the inhibition of integrin interplay. Second, C. burnetii persistence is associated with macrophage activation profiles. Indeed, monocytes (in which C. burnetii survives without replication) exhibit a proinflammatory M1-type response, whereas macrophages (in which C. burnetii slowly replicates) are polarized towards an M2-type. Third, interleukin-10 produced by monocytes is a main factor of the chronic development of Q fever, and murine models confirm the key role of interleukin-10 in C. burnetii persistence. Fourth, apoptotic cells may play a key role in chronic Q fever. The uptake of apoptotic cells by circulating monocytes increases C. burnetii replication by redirecting monocytes toward a non-protective M2 profile. In the presence of interferon-γ, apoptotic cell engulfment is inhibited and monocytes polarized toward an M1 program are able to kill C. burnetii; this is the situation observed in patients with uncomplicated acute Q fever. Finally, we cannot exclude that regulatory T cells may play a role in C. burnetii persistence because their number is increased in patients with chronic Q fever.
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Affiliation(s)
- Amira Ben Amara
- Unité de Recherche sur les Maladies Infectieuses Transmissibles et Emergentes, CNRS-IRD UMR 6236, Institut Fédératif de Recherche 48, Faculté de Médecine, Université de la Méditerranée, Marseille, France
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Tanowitz HB, Jelicks LA, Machado FS, Esper L, Qi X, Desruisseaux MS, Chua SC, Scherer PE, Nagajyothi F. Adipose tissue, diabetes and Chagas disease. ADVANCES IN PARASITOLOGY 2011; 76:235-50. [PMID: 21884894 DOI: 10.1016/b978-0-12-385895-5.00010-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Adipose tissue is the largest endocrine organ in the body and is composed primarily of adipocytes (fat cells) but also contains fibroblasts, endothelial cells, smooth muscle cells, macrophages and lymphocytes. Adipose tissue and the adipocyte are important in the regulation of energy metabolism and of the immune response. Adipocytes also synthesize adipokines such as adiponectin which is important in the regulation of insulin sensitivity and inflammation. Infection of mice with Trypanosoma cruzi results in an upregulation of inflammation in adipose tissue that begins during the acute phase of infection and persists into the chronic phase. The adipocyte is both a target of infection and a reservoir for the parasite during the chronic phase from which recrudescence of the infection may occur during periods of immunosuppression.
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Affiliation(s)
- Herbert B Tanowitz
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
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Kim JS, Ryu MJ, Byun EH, Kim WS, Whang J, Min KN, Shong M, Kim HJ, Shin SJ. Differential immune response of adipocytes to virulent and attenuated Mycobacterium tuberculosis. Microbes Infect 2011; 13:1242-51. [DOI: 10.1016/j.micinf.2011.07.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Revised: 07/07/2011] [Accepted: 07/08/2011] [Indexed: 11/24/2022]
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Ferreira AVM, Segatto M, Menezes Z, Macedo AM, Gelape C, de Oliveira Andrade L, Nagajyothi F, Scherer PE, Teixeira MM, Tanowitz HB. Evidence for Trypanosoma cruzi in adipose tissue in human chronic Chagas disease. Microbes Infect 2011; 13:1002-5. [PMID: 21726660 DOI: 10.1016/j.micinf.2011.06.002] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 06/07/2011] [Accepted: 06/08/2011] [Indexed: 12/19/2022]
Abstract
Trypanosoma cruzi the cause of Chagas disease persists in tissues of infected experimental animals and humans. Here we demonstrate the persistence of the parasite in adipose tissue from of three of 10 elderly seropositive patients with chronic chagasic heart disease. Nine control patients had no parasites in the fat. We also demonstrate that T. cruzi parasitizes primary adipocytes in vitro. Thus, in humans as in mice the parasite may persist in adipose tissue for decades and become a reservoir of infection.
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Socolovschi C, Mediannikov O, Sokhna C, Tall A, Diatta G, Bassene H, Trape JF, Raoult D. Rickettsia felis-associated uneruptive fever, Senegal. Emerg Infect Dis 2010; 16:1140-2. [PMID: 20587190 PMCID: PMC3321914 DOI: 10.3201/eid1607.100070] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
During November 2008–July 2009, we investigated the origin of unknown fever in Senegalese patients with a negative malaria test result, focusing on potential rickettsial infection. Using molecular tools, we found evidence for Rickettsia felis–associated illness in the initial days of infection in febrile Senegalese patients without malaria.
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Affiliation(s)
- Cristina Socolovschi
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, 13385 Marseille, France
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Red Eagle A, Chawla A. In obesity and weight loss, all roads lead to the mighty macrophage. J Clin Invest 2010; 120:3437-40. [PMID: 20877005 DOI: 10.1172/jci44721] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Obesity is associated with infiltration of white adipose tissue (WAT) by macrophages, which contributes to the development of insulin resistance. In this issue of the JCI, Kosteli and colleagues demonstrate that weight loss is unexpectedly also associated with rapid, albeit transient, recruitment of macrophages to WAT and that this appears to be related to lipolysis.
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Affiliation(s)
- Alex Red Eagle
- Department of Genetics, Stanford University School of Medicine, Stanford, California, USA
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Angelakis E, Botelho E, Socolovschi C, Sobas CR, Piketty C, Parola P, Raoult D. Murine typhus as a cause of Fever in travelers from Tunisia and mediterranean areas. J Travel Med 2010; 17:310-5. [PMID: 20920051 DOI: 10.1111/j.1708-8305.2010.00435.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Travelers are exposed to a variety of health risks in unfamiliar environments and fever is a common problem in patients returning from travel abroad. Rickettsial diseases are increasingly frequently being reported among international travelers. Here we present cases of Rickettsia typhi infection, the agent of murine typhus, that were identified in our laboratory the last year, in travelers from Tunisia. METHODS For each patient we tested an acute-phase serum sample and for one patient we tested a convalescent-phase serum sample. IgG and IgM antibody titers were estimated with use of the microimmunofluorescence (MIF) assay. Western blot (WB) assay was performed for all the patients. RESULTS We identified three cases of murine typhus after a travel in Tunisia. All cases were observed during late summer and early autumn and patients were suffering by persistent fever. None of them presented rash or inoculation eschar. MIF was positive for Rickettsia sp. in the acute-phase serum samples of two patients. In one patient, two acute-phase serum samples were Rickettsia sp. negative whereas a third convalescent-phase serum sample that was obtained 2 weeks after was Rickettsia sp. positive. By WB assay we identified infection by R typhi. A treatment was immediately started and patients became apyretic. CONCLUSIONS In the countries of North Europe, although autochthones cases of murine typhus have not been described, sporadic cases of R typhi infection are identified in travelers who visited murine typhus endemic areas. Murine typhus should be considered in the diagnosis of febrile illness without rash in travelers returning from disease endemic areas, like the south Mediterranean area.
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Affiliation(s)
- Emmanouil Angelakis
- URMITE UMR 6236, CNRS-IRD, Faculté de Médecine, Marseille, France Service Maladies Infectieuses et Tropical, Hôpital Nord, Marseille, France
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