496 results match your criteria phagosomes infect

Leishmania donovani Metacyclic Promastigotes Impair Phagosome Properties in Inflammatory Monocytes.

Infect Immun 2021 Jun 16;89(7):e0000921. Epub 2021 Jun 16.

INRS - Centre Armand-Frappier Santé Biotechnologie, Université du Québec, Laval, Quebec, Canada.

Leishmaniasis, a debilitating disease with clinical manifestations ranging from self-healing ulcers to life-threatening visceral pathologies, is caused by protozoan parasites of the genus. These professional vacuolar pathogens are transmitted by infected sand flies to mammalian hosts as metacyclic promastigotes and are rapidly internalized by various phagocyte populations. Classical monocytes are among the first myeloid cells to migrate to infection sites. Read More

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Two sequential activation modules control the differentiation of protective T helper-1 (Th1) cells.

Immunity 2021 Apr 26;54(4):687-701.e4. Epub 2021 Mar 26.

Center for Immunology, Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN 55455 USA. Electronic address:

Interferon-γ (IFN-γ)-producing CD4 T helper-1 (Th1) cells are critical for protection from microbes that infect the phagosomes of myeloid cells. Current understanding of Th1 cell differentiation is based largely on reductionist cell culture experiments. We assessed Th1 cell generation in vivo by studying antigen-specific CD4 T cells during infection with the phagosomal pathogen Salmonella enterica (Se), or influenza A virus (IAV), for which CD4 T cells are less important. Read More

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Human Corneal Epithelial Cells Internalize Aspergillus flavus Spores by Actin-Mediated Endocytosis.

Infect Immun 2021 May 17;89(6). Epub 2021 May 17.

Department of Proteomics, Aravind Medical Research Foundation, Dr. G. Venkataswamy Eye Research Institute, Aravind Eye Care System, Madurai, Tamil Nadu, India

Human corneal epithelial (HCE) cells play a significant role in the innate immune response by secreting cytokines and antimicrobial peptides when they encounter fungal pathogens. But the detailed mechanism of attachment and engulfment of the fungal conidia by HCE cells is not well understood. Here, we show the phagocytosis of conidia by RCB2280 cells and primary HCE cultures using confocal microscopy and proteomic analysis of conidium-containing phagosomes. Read More

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A New Family of Bacteriolytic Proteins in .

Front Cell Infect Microbiol 2020 3;10:617310. Epub 2021 Feb 3.

Department of Cell Physiology and Metabolism, Faculty of Medicine, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland.

Phagocytic cells ingest and destroy bacteria efficiently and in doing so ensure the defense of the human body against infections. Phagocytic amoebae represent a powerful model system to study the intracellular mechanisms ensuring destruction of ingested bacteria in phagosomes. Here, we discovered the presence of a bacteriolytic activity against in cellular extracts from The bacteriolytic activity was detected only at a very acidic pH mimicking the conditions found in phagosomes. Read More

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Protein and DNA Biosynthesis Demonstrated in Host Cell-Free Phagosomes Containing Anaplasma phagocytophilum or Ehrlichia chaffeensis in Axenic Media.

Infect Immun 2021 Mar 17;89(4). Epub 2021 Mar 17.

Center of Excellence for Vector-Borne Diseases, Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA

Rickettsiae belong to the family, which includes mostly tick-transmitted pathogens causing human, canine, and ruminant diseases. Biochemical characterization of the pathogens remains a major challenge because of their obligate parasitism. We investigated the use of an axenic medium for growth of two important pathogens- and -in host cell-free phagosomes. Read More

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Autophagy Receptor Tollip Facilitates Bacterial Autophagy by Recruiting Galectin-7 in Response to Group A Infection.

Front Cell Infect Microbiol 2020 23;10:583137. Epub 2020 Dec 23.

Department of Microbiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.

Bacterial autophagy-a type of macroautophagy that is also termed xenophagy-selectively targets intracellular bacteria such as group A (GAS), a ubiquitous pathogen that causes numerous serious diseases, including pharyngitis, skin infections, and invasive life-threatening infections. Although bacterial autophagy is known to eliminate invading bacteria the action of autophagy receptors, the underlying mechanism remains unclear. Herein, we elucidated that Tollip functions as a bacterial-autophagy receptor in addition to participating involved in the intracellular immunity mechanism that defends against bacterial infection. Read More

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The interplay between emerging human coronavirus infections and autophagy.

Emerg Microbes Infect 2021 Dec;10(1):196-205

Key Laboratory of Molecular Biology of Infectious Diseases (Chinese Ministry of Education), Department of Infectious Diseases, The Second Affiliated Hospital, Institute for Viral Hepatitis, Chongqing Medical University, Chongqing, People's Republic of China.

Following outbreaks of severe acute respiratory syndrome coronavirus (SARS-CoV) and the Middle East respiratory syndrome coronavirus (MERS-CoV) in 2002 and 2012, respectively, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the third highly pathogenic emerging human coronavirus (hCoV). SARS-CoV-2 is currently causing the global coronavirus disease 2019 (COVID-19) pandemic. CoV infections in target cells may stimulate the formation of numerous double-membrane autophagosomes and induce autophagy. Read More

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December 2021

Host Cell Targets of Released Lipid and Secreted Protein Effectors of .

Front Cell Infect Microbiol 2020 23;10:595029. Epub 2020 Oct 23.

Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, United States.

(Mtb) is a very successful pathogen, strictly adapted to humans and the cause of tuberculosis. Its success is associated with its ability to inhibit host cell intrinsic immune responses by using an arsenal of virulence factors of different nature. It has evolved to synthesize a series of complex lipids which form an outer membrane and may also be released to enter host cell membranes. Read More

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"It Takes Two to Tango": Role of Neglected Macrophage Manipulators Coronin 1 and Protein Kinase G in Mycobacterial Pathogenesis.

Front Cell Infect Microbiol 2020 20;10:582563. Epub 2020 Oct 20.

Molecular Immunology and Cellular Microbiology Laboratory, Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, India.

Macrophages being the connecting link between innate and adaptive immune system plays a crucial role in microbial antigen presentation and orchestrates the subsequent clearance of microorganisms. Microbial invasion of macrophages trigger a plethora of signaling cascades, which interact among them to generate a dynamically altered hostile environment, that ultimately leads to disruption of microbial pathogenesis. Paradoxically, . Read More

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Video Microscopic Analysis of Invasion of Toxoplasma gondii into Peritoneal Macrophages.

J Parasitol 2020 11;106(6):715-720

School of Basic Medical Sciences, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China.

Toxoplasma gondii is an obligate intracellular protozoan parasite that can infect all nucleated cells through active invasion. Some non-canonical pathways for T. gondii infection of macrophages have recently been reported. Read More

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November 2020

Calcium Pump CtpF Modulates the Autophagosome in an mTOR-Dependent Manner.

Front Cell Infect Microbiol 2020 16;10:461. Epub 2020 Sep 16.

Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India.

Calcium is a very important second messenger, whose concentration in various cellular compartments is under tight regulation. A disturbance in the levels of calcium in these compartments can play havoc in the cell, as it regulates various cellular processes by direct or indirect mechanisms. Here, we have investigated the functional importance of a calcium transporting P2A ATPase, CtpF of (Mtb) in the pathogen's interaction with the host. Read More

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PGRS Domain of Rv0297 of Is Involved in Modulation of Macrophage Functions to Favor Bacterial Persistence.

Front Cell Infect Microbiol 2020 11;10:451. Epub 2020 Sep 11.

Institute of Molecular Medicine, Jamia Hamdard, New Delhi, India.

Rv0297-encoded PE_PGRS5 has been known to be expressed at the later stages of infection and in acidified phagosomes during transcriptome and proteomic studies. The possible role of Rv0297 in the modulation of phagosomal maturation and in providing protection against a microbicidal environment has been hypothesized. We show that Rv0297PGRS is involved in modulating the calcium homeostasis of macrophages followed by impedance of the phagolysosomal acidification process. Read More

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Gene expression tryptophan aspartate coat protein in determining latent tuberculosis infection using immunocytochemistry and real time polimerase chain reaction.

Infect Dis Rep 2020 07 7;12(Suppl 1):8733. Epub 2020 Jul 7.

Department of Pulmonology, Faculty of Medicine, Universitas Airlangga.

Background: Tuberculosis (TB) remains a major cause of morbidity and mortality worldwide. Problem of Latent Tuberculosis Infection (LTBI) is increasing in number especially in countries with high TB incidence rate, such as Indonesia. Although not every LTBI will become active TB, if untreated and not handled appropriately it can still be a source of transmission and may increase the rate of resistance to the first-line TB drugs. Read More

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The LysR Family Regulator RipR Activates the SPI-13-Encoded Itaconate Degradation Cluster.

Infect Immun 2020 09 18;88(10). Epub 2020 Sep 18.

Department of Molecular Genetics, University of Toronto, Toronto, Canada

Itaconate is a dicarboxylic acid that inhibits the isocitrate lyase enzyme of the bacterial glyoxylate shunt. Activated macrophages have been shown to produce itaconate, suggesting that these immune cells may employ this metabolite as a weapon against invading bacteria. Here, we demonstrate that , itaconate can exhibit bactericidal effects under acidic conditions similar to the pH of a macrophage phagosome. Read More

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September 2020

Risk1, a Phosphatidylinositol 3-Kinase Effector, Promotes Rickettsia typhi Intracellular Survival.

mBio 2020 06 16;11(3). Epub 2020 Jun 16.

Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA

To establish a habitable intracellular niche, various pathogenic bacteria secrete effectors that target intracellular trafficking and modulate phosphoinositide (PI) metabolism. Murine typhus, caused by the obligate intracellular bacterium , remains a severe disease in humans. However, the mechanisms by which effector molecules contribute to internalization by induced phagocytosis and subsequent phagosomal escape into the cytosol to facilitate the intracellular growth of the bacteria remain ill-defined. Read More

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Stochastic dynamics of Francisella tularensis infection and replication.

PLoS Comput Biol 2020 06 1;16(6):e1007752. Epub 2020 Jun 1.

Department of Applied Mathematics, University of Leeds, Leeds, United Kingdom.

We study the pathogenesis of Francisella tularensis infection with an experimental mouse model, agent-based computation and mathematical analysis. Following inhalational exposure to Francisella tularensis SCHU S4, a small initial number of bacteria enter lung host cells and proliferate inside them, eventually destroying the host cell and releasing numerous copies that infect other cells. Our analysis of disease progression is based on a stochastic model of a population of infectious agents inside one host cell, extending the birth-and-death process by the occurrence of catastrophes: cell rupture events that affect all bacteria in a cell simultaneously. Read More

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Clofazimine Reduces the Survival of in Macrophages and Mice.

ACS Infect Dis 2020 05 29;6(5):1238-1249. Epub 2020 Apr 29.

Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado 80309, United States.

Drug resistant pathogens are on the rise, and new treatments are needed for bacterial infections. Efforts toward antimicrobial discovery typically identify compounds that prevent bacterial growth in microbiological media. However, the microenvironments to which pathogens are exposed during infection differ from rich media and alter the biology of the pathogen. Read More

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Fighting Persistence: How Chronic Infections with Mycobacterium tuberculosis Evade T Cell-Mediated Clearance and New Strategies To Defeat Them.

Infect Immun 2020 06 22;88(7). Epub 2020 Jun 22.

Michigan State University, East Lansing, Michigan, USA

Chronic bacterial infections are caused by pathogens that persist within their hosts and avoid clearance by the immune system. Treatment and/or detection of such pathogens is difficult, and the resulting pathologies are often deleterious or fatal. There is an urgent need to develop protective vaccines and host-directed therapies that synergize with antibiotics to prevent pathogen persistence and infection-associated pathologies. Read More

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Staphylococcus aureus Infects Osteoclasts and Replicates Intracellularly.

mBio 2019 10 15;10(5). Epub 2019 Oct 15.

Division of Bone & Mineral Diseases, Musculoskeletal Research Center, Washington University School of Medicine, Saint Louis, Missouri, USA

Osteomyelitis (OM), or inflammation of bone tissue, occurs most frequently as a result of bacterial infection and severely perturbs bone structure. OM is predominantly caused by , and even with proper treatment, OM has a high rate of recurrence and chronicity. While has been shown to infect osteoblasts, it remains unclear whether osteoclasts (OCs) are also a target of intracellular infection. Read More

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October 2019

: Strain-Specific Modulation of Phagosome Maturation.

Front Cell Infect Microbiol 2019 6;9:319. Epub 2019 Sep 6.

INRS - Centre Armand-Frappier Santé Biotechnologie, Université du Québec, Laval, QC, Canada.

() is responsible for the largest number of American tegumentary leishmaniasis (ATL) in Brazil. ATL can present several clinical forms including typical (TL) and atypical (AL) cutaneous and mucocutaneous (ML) lesions. To identify parasite and host factors potentially associated with these diverse clinical manifestations, we first surveyed the expression of two virulence-associated glycoconjugates, lipophosphoglycan (LPG) and the metalloprotease GP63 by a panel of promastigotes of Leishmania braziliensis strains isolated from patients with different clinical manifestations of ATL and from the sand fly vector. Read More

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Rubicon-Dependent Lc3 Recruitment to -Containing Phagosomes Is a Host Defense Mechanism Triggered Independently From Major Bacterial Virulence Factors.

Front Cell Infect Microbiol 2019 2;9:279. Epub 2019 Aug 2.

Institute of Biology Leiden, Leiden University, Leiden, Netherlands.

Intracellular pathogens such as depend on their molecular virulence factors to evade host defense responses like autophagy. Using a zebrafish systemic infection model, we have previously shown that phagocytes, predominantly macrophages, target Typhimurium by an autophagy-related pathway known as Lc3-associated phagocytosis (LAP), which is dependent on the host protein Rubicon. Here, we explore the influence of virulence factors on pathogenicity in the zebrafish model and induction of LAP as a defense response. Read More

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Type II Secretion Promotes Bacterial Growth within the -Containing Vacuole in Infected Amoebae.

Infect Immun 2019 11 18;87(11). Epub 2019 Oct 18.

Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois, USA

It was previously determined that the type II secretion system (T2SS) promotes the ability of to grow in coculture with amoebae. Here, we discerned the stage of intracellular infection that is potentiated by comparing the wild-type and T2SS mutant legionellae for their capacity to parasitize Whereas the mutant behaved normally for entry into the host cells and subsequent evasion of degradative lysosomes, it was impaired in the ability to replicate, with that defect being first evident at approximately 9 h postentry. The replication defect was initially documented in three ways: by determining the numbers of CFU recovered from the lysates of the infected monolayers, by monitoring the levels of fluorescence associated with amoebal monolayers infected with green fluorescent protein (GFP)-expressing bacteria, and by utilizing flow cytometry to quantitate the amounts of GFP-expressing bacteria in individual amoebae. Read More

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November 2019

Inhibition of the ULK1 protein complex suppresses -induced autophagy and cell death.

J Biol Chem 2019 09 6;294(39):14289-14307. Epub 2019 Aug 6.

Strathclyde Institute for Pharmacy and Biomedical Science, University of Strathclyde, Glasgow G4-0RE, Scotland, United Kingdom

Autophagy plays multiple roles in host cells challenged with extracellular pathogens. Here, we aimed to explore whether autophagy inhibition could prevent bacterial infections. We first confirmed widely distinct patterns of autophagy responses in host cells infected with , as compared with Only infection with produced strong accumulation of lipidated autophagy-related protein LC3B (LC3B-II). Read More

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September 2019

Calpain regulates CVB3 induced viral myocarditis by promoting autophagic flux upon infection.

Microbes Infect 2020 Jan - Feb;22(1):46-54. Epub 2019 Jul 15.

Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou, 215123, China. Electronic address:

Calpains are calcium-activated neutral cysteine proteases. The dysregulation of calpain activity has been found to be related to cardiovascular diseases, for which calpain inhibition is used as a treatment. Viral myocarditis (VMC) is primarily caused by Coxsackievirus group B3 virus infection (CVB3). Read More

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October 2020

Phosphatidylinositol Kinases and Phosphatases in .

Front Cell Infect Microbiol 2019 6;9:150. Epub 2019 Jun 6.

Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.

Phosphatidylinositol (PtdIns) metabolism is indispensable in eukaryotes. Phosphoinositides (PIs) are phosphorylated derivatives of PtdIns and consist of seven species generated by reversible phosphorylation of the inositol moieties at the positions 3, 4, and 5. Each of the seven PIs has a unique subcellular and membrane domain distribution. Read More

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January 2020

Infect and Inject: How Exploits Its Major Virulence-Associated Type VII Secretion System, ESX-1.

Microbiol Spectr 2019 05;7(3)

Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461.

is an ancient master of the art of causing human disease. One important weapon within its fully loaded arsenal is the type VII secretion system. has five of them: ESAT-6 secretion systems (ESX) 1 to 5. Read More

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A Chemical Genetics Screen Reveals Influence of p38 Mitogen-Activated Protein Kinase and Autophagy on Phagosome Development and Intracellular Replication of Brucella neotomae in Macrophages.

Infect Immun 2019 08 23;87(8). Epub 2019 Jul 23.

Department of Pathology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA

is an intracellular bacterial pathogen that causes chronic systemic infection in domesticated livestock and poses a zoonotic infectious risk to humans. The virulence of is critically dependent on its ability to replicate and survive within host macrophages. modulates host physiological pathways and cell biology in order to establish a productive intracellular replicative niche. Read More

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The HIF-1α/LC3-II Axis Impacts Fungal Immunity in Human Macrophages.

Infect Immun 2019 07 20;87(7). Epub 2019 Jun 20.

Department of Infectious Diseases and Microbiology, University of Lübeck, Lübeck, Germany

The fungal pathogen causes a spectrum of disease, ranging from local pulmonary infection to disseminated disease. The organism seeks residence in macrophages, which are permissive for its survival. Hypoxia-inducible factor 1α (HIF-1α), a principal regulator of innate immunity to pathogens, is necessary for macrophage-mediated immunity to in mice. Read More

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Infection of Primary Human Alveolar Macrophages Alters Staphylococcus aureus Toxin Production and Activity.

Infect Immun 2019 07 20;87(7). Epub 2019 Jun 20.

Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA

Pulmonary pathogens encounter numerous insults, including phagocytic cells designed to degrade bacteria, while establishing infection in the human lung. is a versatile, opportunistic pathogen that can cause severe pneumonia, and methicillin-resistant isolates are of particular concern. Recent reports present conflicting data regarding the ability of to survive and replicate within macrophages. Read More

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JVA, an isoniazid analogue, is a bioactive compound against a clinical isolate of the Mycobacterium avium complex.

Tuberculosis (Edinb) 2019 03 5;115:108-112. Epub 2019 Mar 5.

Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Instituto Nacional de Ciência e Tecnologia em Doenças Tropicais (INCT-DT), CNPq MCT, Salvador, BA, Brazil. Electronic address:

Bacteria belonging to Mycobacterium avium complex are organisms of low pathogenicity that infect immunosuppressed individuals. Infection is treated with an antimicrobial macrolide, Clarithromycin (CAM) or Azitromycin, associated with Ethambutol and Rifabutin during 12 months. Regimen long duration and side effects hinder patient's commitment to treatment favoring emergence of antibiotic resistance. Read More

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