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Tavares J, Costa DM, Teixeira AR, Cordeiro-da-Silva A, Amino R. In vivo imaging of pathogen homing to the host tissues. Methods 2017; 127:37-44. [PMID: 28522323 DOI: 10.1016/j.ymeth.2017.05.008] [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: 03/02/2017] [Revised: 04/19/2017] [Accepted: 05/10/2017] [Indexed: 12/19/2022] Open
Abstract
Hematogenous dissemination followed by tissue tropism is a characteristic of the infectious process of many pathogens including those transmitted by blood-feeding vectors. After entering into the blood circulation, these pathogens must arrest in the target organ before they infect a specific tissue. Here, we describe a non-invasive method to visualize and quantify the homing of pathogens to the host tissues. By using in vivo bioluminescence imaging we quantify the accumulation of luciferase-expressing parasites in the host organs during the first minutes following their intravascular inoculation in mice. Using this technique we show that in the malarial infection, once in the blood circulation, most of bioluminescent Plasmodium berghei sporozoites, the parasite stage transmitted to the host skin by a mosquito bite, rapidly home to the liver where they invade and develop inside hepatocytes. This homing is specific to this developmental stage since blood stage parasites do not accumulate in the liver, as well as extracellular Trypanosoma brucei bloodstream forms and liver-infecting Leishmania infantum amastigotes. Finally, this method can be used to study the dynamics of tissue tropism of parasites, dissect the molecular and cellular basis of their increased arrest in organs and to evaluate immune interventions designed to block this targeted interaction.
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Affiliation(s)
- Joana Tavares
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Portugal.
| | - David Mendes Costa
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Portugal
| | - Ana Rafaela Teixeira
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Portugal
| | - Anabela Cordeiro-da-Silva
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Portugal; Faculdade de Farmácia da Universidade do Porto, Departamento de Ciências Biológicas, Portugal
| | - Rogerio Amino
- Unit of Malaria Infection and Immunity, Institut Pasteur, Paris, France.
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102
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Brandl K, Kumar V, Eckmann L. Gut-liver axis at the frontier of host-microbial interactions. Am J Physiol Gastrointest Liver Physiol 2017; 312:G413-G419. [PMID: 28232456 PMCID: PMC5451561 DOI: 10.1152/ajpgi.00361.2016] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 02/13/2017] [Accepted: 02/20/2017] [Indexed: 01/31/2023]
Abstract
Liver and intestine are tightly linked through the venous system of the portal circulation. Consequently, the liver is the primary recipient of gut-derived products, most prominently dietary nutrients and microbial components. It functions as a secondary "firewall" and protects the body from intestinal pathogens and other microbial products that have crossed the primary barrier of the intestinal tract. Disruption of the intestinal barrier enhances microbial exposure of the liver, which can have detrimental or beneficial effects in the organ depending on the specific circumstances. Conversely, the liver also exerts influence over intestinal microbial communities via secretion of bile acids and IgA antibodies. This mini-review highlights key findings and concepts in the area of host-microbial interactions as pertinent to the bilateral communication between liver and gut and highlights the concept of the gut-liver axis.
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Affiliation(s)
- Katharina Brandl
- 1Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, California; and
| | - Vipin Kumar
- 2Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, California
| | - Lars Eckmann
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, California
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103
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Bennett KM, Rooijakkers SHM, Gorham RD. Let's Tie the Knot: Marriage of Complement and Adaptive Immunity in Pathogen Evasion, for Better or Worse. Front Microbiol 2017; 8:89. [PMID: 28197139 PMCID: PMC5281603 DOI: 10.3389/fmicb.2017.00089] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 01/12/2017] [Indexed: 01/16/2023] Open
Abstract
The complement system is typically regarded as an effector arm of innate immunity, leading to recognition and killing of microbial invaders in body fluids. Consequently, pathogens have engaged in an arms race, evolving molecules that can interfere with proper complement responses. However, complement is no longer viewed as an isolated system, and links with other immune mechanisms are continually being discovered. Complement forms an important bridge between innate and adaptive immunity. While its roles in innate immunity are well-documented, its function in adaptive immunity is less characterized. Therefore, it is no surprise that the field of pathogenic complement evasion has focused on blockade of innate effector functions, while potential inhibition of adaptive immune responses (via complement) has been overlooked to a certain extent. In this review, we highlight past and recent developments on the involvement of complement in the adaptive immune response. We discuss the mechanisms by which complement aids in lymphocyte stimulation and regulation, as well as in antigen presentation. In addition, we discuss microbial complement evasion strategies, and highlight specific examples in the context of adaptive immune responses. These emerging ties between complement and adaptive immunity provide a catalyst for future discovery in not only the field of adaptive immune evasion but in elucidating new roles of complement.
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Affiliation(s)
- Kaila M Bennett
- Department of Medical Microbiology, University Medical Center Utrecht Utrecht, Netherlands
| | - Suzan H M Rooijakkers
- Department of Medical Microbiology, University Medical Center Utrecht Utrecht, Netherlands
| | - Ronald D Gorham
- Department of Medical Microbiology, University Medical Center Utrecht Utrecht, Netherlands
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104
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Piao X, Yamazaki S, Komazawa-Sakon S, Miyake S, Nakabayashi O, Kurosawa T, Mikami T, Tanaka M, Van Rooijen N, Ohmuraya M, Oikawa A, Kojima Y, Kakuta S, Uchiyama Y, Tanaka M, Nakano H. Depletion of myeloid cells exacerbates hepatitis and induces an aberrant increase in histone H3 in mouse serum. Hepatology 2017; 65:237-252. [PMID: 27770461 DOI: 10.1002/hep.28878] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 08/18/2016] [Accepted: 09/14/2016] [Indexed: 12/14/2022]
Abstract
UNLABELLED Tissue-resident macrophages and bone marrow (BM)-derived monocytes play a crucial role in the maintenance of tissue homeostasis; however, their contribution to recovery from acute tissue injury is not fully understood. To address this issue, we generated an acute murine liver injury model using hepatocyte-specific Cflar-deficient (CflarHep-low ) mice. Cellular FLICE-inhibitory protein expression was down-regulated in Cflar-deficient hepatocytes, which thereby increased susceptibility of hepatocytes to death receptor-induced apoptosis. CflarHep-low mice developed acute hepatitis and recovered with clearance of apoptotic hepatocytes at 24 hours after injection of low doses of tumor necrosis factor α (TNFα), which could not induce hepatitis in wild-type (WT) mice. Depletion of Kupffer cells (KCs) by clodronate liposomes did not impair clearance of dying hepatocytes or exacerbate hepatitis in CflarHep-low mice. To elucidate the roles of BM-derived monocytes and neutrophils in clearance of apoptotic hepatocytes, we examined the effect of depletion of these cells on TNFα-induced hepatitis in CflarHep-low mice. We reconstituted CflarHep-low mice with BM cells from transgenic mice in which human diphtheria toxin receptor (DTR) was expressed under control of the lysozyme M (LysM) promoter. TNFα-induced infiltration of myeloid cells, including monocytes and neutrophils, was completely ablated in LysM-DTR BM-reconstituted CflarHep-low mice pretreated with diphtheria toxin, whereas KCs remained present in the livers. Under these experimental conditions, LysM-DTR BM-reconstituted CflarHep-low mice rapidly developed severe hepatitis and succumbed within several hours of TNFα injection. We found that serum interleukin-6 (IL-6), TNFα, and histone H3 were aberrantly increased in LysM-DTR BM-reconstituted, but not in WT BM-reconstituted, CflarHep-low mice following TNFα injection. CONCLUSION These findings indicate an unexpected role of myeloid cells in decreasing serum IL-6, TNFα, and histone H3 levels via the suppression of TNFα-induced hepatocyte apoptosis. (Hepatology 2017;65:237-252).
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Affiliation(s)
- Xuehua Piao
- Department of Biochemistry, Toho University School of Medicine, Tokyo, Japan
| | - Soh Yamazaki
- Department of Biochemistry, Toho University School of Medicine, Tokyo, Japan
| | | | - Sanae Miyake
- Department of Biochemistry, Toho University School of Medicine, Tokyo, Japan
| | - Osamu Nakabayashi
- Department of Biochemistry, Toho University School of Medicine, Tokyo, Japan
| | - Takeyuki Kurosawa
- Department of Biochemistry, Toho University School of Medicine, Tokyo, Japan
| | - Tetsuo Mikami
- Department of Pathology, Toho University School of Medicine, Tokyo, Japan
| | - Minoru Tanaka
- Department of Regenerative Medicine, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Nico Van Rooijen
- Department of Molecular Cell Biology, Faculty of Medicine, Vrije Universiteit, Amsterdam, Netherlands
| | - Masaki Ohmuraya
- Center for Animal Resources and Development, Kumamoto University, Kumamoto, Japan
| | - Akira Oikawa
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan.,Faculty of Agriculture, Yamagata University, Yamagata, Japan
| | - Yuko Kojima
- Laboratory of Biomedical Imaging Research, Biomedical Research Center, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Soichiro Kakuta
- Department of Cell Biology and Neuroscience, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Yasuo Uchiyama
- Department of Cell Biology and Neuroscience, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Masato Tanaka
- Laboratory of Immune regulation, School of Life Science, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
| | - Hiroyasu Nakano
- Department of Biochemistry, Toho University School of Medicine, Tokyo, Japan
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