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Badaut J, Blochet C, Obenaus A, Hirt L. Physiological and pathological roles of caveolins in the central nervous system. Trends Neurosci 2024; 47:651-664. [PMID: 38972795 PMCID: PMC11324375 DOI: 10.1016/j.tins.2024.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 05/14/2024] [Accepted: 06/12/2024] [Indexed: 07/09/2024]
Abstract
Caveolins are a family of transmembrane proteins located in caveolae, small lipid raft invaginations of the plasma membrane. The roles of caveolin-enriched lipid rafts are diverse, and include mechano-protection, lipid homeostasis, metabolism, transport, and cell signaling. Caveolin-1 (Cav-1) and other caveolins were described in endothelial cells and later in other cell types of the central nervous system (CNS), including neurons, astrocytes, oligodendrocytes, microglia, and pericytes. This pancellular presence of caveolins demands a better understanding of their functional roles in each cell type. In this review we describe the various functions of Cav-1 in the cells of normal and pathological brains. Several emerging preclinical findings suggest that Cav-1 could represent a potential therapeutic target in brain disorders.
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Affiliation(s)
- Jérôme Badaut
- CNRS UMR 5536 RMSB-University of Bordeaux, Bordeaux, France; Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA.
| | - Camille Blochet
- Department of Clinical Neurosciences, CHUV, Lausanne, Switzerland; Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
| | - André Obenaus
- Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA; Division of Biomedical Sciences, University of California Riverside, Riverside, CA, USA
| | - Lorenz Hirt
- Department of Clinical Neurosciences, CHUV, Lausanne, Switzerland; Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
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Morel C, Lemerle E, Tsai FC, Obadia T, Srivastava N, Marechal M, Salles A, Albert M, Stefani C, Benito Y, Vandenesch F, Lamaze C, Vassilopoulos S, Piel M, Bassereau P, Gonzalez-Rodriguez D, Leduc C, Lemichez E. Caveolin-1 protects endothelial cells from extensive expansion of transcellular tunnel by stiffening the plasma membrane. eLife 2024; 12:RP92078. [PMID: 38517935 PMCID: PMC10959525 DOI: 10.7554/elife.92078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/24/2024] Open
Abstract
Large transcellular pores elicited by bacterial mono-ADP-ribosyltransferase (mART) exotoxins inhibiting the small RhoA GTPase compromise the endothelial barrier. Recent advances in biophysical modeling point toward membrane tension and bending rigidity as the minimal set of mechanical parameters determining the nucleation and maximal size of transendothelial cell macroaperture (TEM) tunnels induced by bacterial RhoA-targeting mART exotoxins. We report that cellular depletion of caveolin-1, the membrane-embedded building block of caveolae, and depletion of cavin-1, the master regulator of caveolae invaginations, increase the number of TEMs per cell. The enhanced occurrence of TEM nucleation events correlates with a reduction in cell height due to the increase in cell spreading and decrease in cell volume, which, together with the disruption of RhoA-driven F-actin meshwork, favor membrane apposition for TEM nucleation. Strikingly, caveolin-1 specifically controls the opening speed of TEMs, leading to their dramatic 5.4-fold larger widening. Consistent with the increase in TEM density and width in siCAV1 cells, we record a higher lethality in CAV1 KO mice subjected to a catalytically active mART exotoxin targeting RhoA during staphylococcal bloodstream infection. Combined theoretical modeling with independent biophysical measurements of plasma membrane bending rigidity points toward a specific contribution of caveolin-1 to membrane stiffening in addition to the role of cavin-1/caveolin-1-dependent caveolae in the control of membrane tension homeostasis.
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Affiliation(s)
- Camille Morel
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Inserm U1306, Unité des Toxines Bactériennes, Département de MicrobiologieParisFrance
| | - Eline Lemerle
- Sorbonne Université, INSERM UMR974, Institut de Myologie, Centre de Recherche en MyologieParisFrance
| | - Feng-Ching Tsai
- Institut Curie, PSL Research University, CNRS UMR168, Physics of Cells and Cancer LaboratoryParisFrance
| | - Thomas Obadia
- Institut Pasteur, Université Paris Cité, Bioinformatics and Biostatistics HubParisFrance
- Institut Pasteur, Université Paris Cité, G5 Infectious Diseases Epidemiology and AnalyticsParisFrance
| | - Nishit Srivastava
- Institut Curie and Institut Pierre Gilles de Gennes, PSL Research University, Sorbonne UniversityParisFrance
| | - Maud Marechal
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Inserm U1306, Unité des Toxines Bactériennes, Département de MicrobiologieParisFrance
| | - Audrey Salles
- Institut Pasteur, Université Paris Cité, Photonic Bio-Imaging, Centre de Ressources et Recherches Technologiques (UTechS-PBI, C2RT)ParisFrance
| | - Marvin Albert
- Institut Pasteur, Université Paris Cité, Image Analysis HubParisFrance
| | - Caroline Stefani
- Benaroya Research Institute at Virginia Mason, Department of ImmunologySeattleUnited States
| | - Yvonne Benito
- Centre National de Référence des Staphylocoques, Hospices Civiles de LyonLyonFrance
| | - François Vandenesch
- CIRI, Centre International de Recherche en Infectiologie, Université de Lyon, Inserm U1111, Université Claude Bernard Lyon 1, CNRS UMR5308, ENS de Lyon, Lyon, FranceLyonFrance
| | - Christophe Lamaze
- Institut Curie, PSL Research University, INSERM U1143, CNRS UMR3666, Membrane Mechanics and Dynamics of Intracellular Signaling LaboratoryParisFrance
| | - Stéphane Vassilopoulos
- Sorbonne Université, INSERM UMR974, Institut de Myologie, Centre de Recherche en MyologieParisFrance
| | - Matthieu Piel
- Institut Curie and Institut Pierre Gilles de Gennes, PSL Research University, Sorbonne UniversityParisFrance
| | - Patricia Bassereau
- Institut Curie, PSL Research University, CNRS UMR168, Physics of Cells and Cancer LaboratoryParisFrance
| | | | - Cecile Leduc
- Université Paris Cité, Institut Jacques Monod, CNRS UMR7592ParisFrance
| | - Emmanuel Lemichez
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Inserm U1306, Unité des Toxines Bactériennes, Département de MicrobiologieParisFrance
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Xiao M, Li G, Yang H. Microbe-host interactions: structure and functions of Gram-negative bacterial membrane vesicles. Front Microbiol 2023; 14:1225513. [PMID: 37720140 PMCID: PMC10500606 DOI: 10.3389/fmicb.2023.1225513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 08/17/2023] [Indexed: 09/19/2023] Open
Abstract
Bacteria-host interaction is a common, relevant, and intriguing biological phenomena. The host reacts actively or passively to the bacteria themselves, their products, debris, and so on, through various defense systems containing the immune system, the bacteria communicate with the local or distal tissues of the host via their own surface antigens, secreted products, nucleic acids, etc., resulting in relationships of attack and defense, adaptation, symbiosis, and even collaboration. The significance of bacterial membrane vesicles (MVs) as a powerful vehicle for the crosstalk mechanism between the two is growing. In the recent decade, the emergence of MVs in microbial interactions and a variety of bacterial infections, with multiple adhesions to host tissues, cell invasion and evasion of host defense mechanisms, have brought MVs to the forefront of bacterial pathogenesis research. Whereas MVs are a complex combination of molecules not yet fully understood, research into its effects, targeting and pathogenic components will advance its understanding and utilization. This review will summarize structural, extraction and penetration information on several classes of MVs and emphasize the role of MVs in transport and immune response activation. Finally, the potential of MVs as a therapeutic method will be highlighted, as will future research prospects.
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Affiliation(s)
- Min Xiao
- Yunnan Key Laboratory of Stomatology, Kunming Medical University, Kunming, Yunnan, China
- Department of Dental Research, The Affiliated Stomatology Hospital of Kunming Medical University, Kunming, Yunnan, China
| | - Guiding Li
- Yunnan Key Laboratory of Stomatology, Kunming Medical University, Kunming, Yunnan, China
- Department of Dental Research, The Affiliated Stomatology Hospital of Kunming Medical University, Kunming, Yunnan, China
| | - Hefeng Yang
- Yunnan Key Laboratory of Stomatology, Kunming Medical University, Kunming, Yunnan, China
- Department of Dental Research, The Affiliated Stomatology Hospital of Kunming Medical University, Kunming, Yunnan, China
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Valigurová A, Kolářová I. Unrevealing the Mystery of Latent Leishmaniasis: What Cells Can Host Leishmania? Pathogens 2023; 12:pathogens12020246. [PMID: 36839518 PMCID: PMC9967396 DOI: 10.3390/pathogens12020246] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Revised: 01/31/2023] [Accepted: 02/01/2023] [Indexed: 02/05/2023] Open
Abstract
Leishmania spp. (Kinetoplastida) are unicellular parasites causing leishmaniases, neglected tropical diseases of medical and veterinary importance. In the vertebrate host, Leishmania parasites multiply intracellularly in professional phagocytes, such as monocytes and macrophages. However, their close relative with intracellular development-Trypanosoma cruzi-can unlock even non-professional phagocytes. Since Leishmania and T. cruzi have similar organelle equipment, is it possible that Leishmania can invade and even proliferate in cells other than the professional phagocytes? Additionally, could these cells play a role in the long-term persistence of Leishmania in the host, even in cured individuals? In this review, we provide (i) an overview of non-canonical Leishmania host cells and (ii) an insight into the strategies that Leishmania may use to enter them. Many studies point to fibroblasts as already established host cells that are important in latent leishmaniasis and disease epidemiology, as they support Leishmania transformation into amastigotes and even their multiplication. To invade them, Leishmania causes damage to their plasma membrane and exploits the subsequent repair mechanism via lysosome-triggered endocytosis. Unrevealing the interactions between Leishmania and its non-canonical host cells may shed light on the persistence of these parasites in vertebrate hosts, a way to control latent leishmaniasis.
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Affiliation(s)
- Andrea Valigurová
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic
- Correspondence: (A.V.); (I.K.)
| | - Iva Kolářová
- Department of Parasitology, Faculty of Science, Charles University, Albertov 6, 128 44 Prague, Czech Republic
- Correspondence: (A.V.); (I.K.)
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G-Protein-Coupled Receptors Mediate Modulations of Cell Viability and Drug Sensitivity by Aberrantly Expressed Recoverin 3 within A549 Cells. Int J Mol Sci 2023; 24:ijms24010771. [PMID: 36614215 PMCID: PMC9820968 DOI: 10.3390/ijms24010771] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/21/2022] [Accepted: 12/29/2022] [Indexed: 01/03/2023] Open
Abstract
To elucidate the currently unknown molecular mechanisms responsible for the aberrant expression of recoverin (Rec) within cancerous cells, we examined two-dimensional (2D) and three-dimensional (3D) cultures of Rec-negative lung adenocarcinoma A549 cells which had been transfected with a plasmid containing human recoverin cDNA (A549 Rec) or an empty plasmid as a mock control (A549 MOCK). Using these cells, we measured cytotoxicity by several anti-tumor agents (2D), cellular metabolism including mitochondrial and glycolytic functions by a Seahorse bio-analyzer (2D), the physical properties, size and stiffness of the 3D spheroids, trypsin sensitivities (2D and 3D), and RNA sequencing analysis (2D). Compared with the A549 MOCK, the A549 Rec cells showed (1) more sensitivity toward anti-tumor agents (2D) and a 0.25% solution of trypsin (3D); (2) a metabolic shift from glycolysis to oxidative phosphorylation; and (3) the formation of larger and stiffer 3D spheroids. RNA sequencing analysis and bioinformatic analyses of the differentially expressed genes (DEGs) using Gene Ontology (GO) enrichment analysis suggested that aberrantly expressed Rec is most likely associated with several canonical pathways including G-protein-coupled receptor (GPCR)-mediated signaling and signaling by the cAMP response element binding protein (CREB). The findings reported here indicate that the aberrantly expressed Rec-induced modulation of the cell viability and drug sensitivity may be GPCR mediated.
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Aspalathus linearis (Rooibos) and Agmatine May Act Synergistically to Beneficially Modulate Intestinal Tight Junction Integrity and Inflammatory Profile. Pharmaceuticals (Basel) 2022; 15:ph15091097. [PMID: 36145318 PMCID: PMC9501288 DOI: 10.3390/ph15091097] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 08/17/2022] [Accepted: 08/28/2022] [Indexed: 11/25/2022] Open
Abstract
In order to promote gastrointestinal health, significant increases in the prevalence of gastrointestinal disorders should be paralleled by similar surges in therapeutics research. Nutraceutical interventions may play a significant role in patient management. The current study aimed to determine the potential of Aspalathus linearis (rooibos) to prevent gastrointestinal dysregulation resulting from high-dose trace-amine (TA) exposure. Considering the substantial female bias in functional gastrointestinal disorders, and the suggested phytoestrogenicity of rooibos, the study design allowed for a comparison between the effects of an ethanol extract of green rooibos and 17β-estradiol (E2). High levels of ρ-tyramine (TYR) and agmatine (AGM), but not β-phenethylamine (PEA) or tryptamine (TRP), resulted in prostaglandin E2 (PGE2) hypersecretion, increased tight-junction protein (TJP; occludin and ZO-1) secretion and (dissimilarly) disrupted the TJP cellular distribution profile. Modulating benefits of rooibos and E2 were TA-specific. Rooibos pre-treatment generally reduced IL-8 secretion across all TA conditions and prevented PGE2 hypersecretion after exposure to both TYR and AGM, but was only able to normalise TJP levels and the distribution profile in AGM-exposed cells. In contrast, E2 pre-treatment prevented only TYR-associated PGE2 hypersecretion and TJP dysregulation. Together, the data suggest that the antioxidant and anti-inflammatory effects of rooibos, rather than phytoestrogenicity, affect benefits illustrated for rooibos.
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Factors Affecting Spontaneous Endocytosis and Survival of Probiotic Lactobacilli in Human Intestinal Epithelial Cells. Microorganisms 2022; 10:microorganisms10061142. [PMID: 35744660 PMCID: PMC9230732 DOI: 10.3390/microorganisms10061142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 05/25/2022] [Accepted: 05/30/2022] [Indexed: 11/29/2022] Open
Abstract
Mutualistic bacteria have different forms of interaction with the host. In contrast to the invasion of pathogenic bacteria, naturally occurring internalization of commensal bacteria has not been studied in depth. Three in vitro methods, gentamicin protection, flow cytometry and confocal laser scanning microscopy, have been implemented to accurately assess the internalization of two lactobacillus strains—Lacticaseibacillus paracasei BL23 and Lacticaseibacillus rhamnosus GG—in Caco-2 and T84 intestinal epithelial cells (IECs) under a variety of physiological conditions and with specific inhibitors. First and most interesting, internalization occurred at a variable rate that depends on the bacterial strain and IEC line, and the most efficient was BL23 internalization by T84 and, second, efficient internalization required active IEC proliferation, as it improved naturally at the early confluence stages and by stimulation with epidermal growth factor (EGF). IFN-γ is bound to innate immune responses and autolysis; this cytokine had a significant effect on internalization, as shown by flow cytometry, but increased internalization was not perceived in all conditions, possibly because it was also stimulating autolysis and, as a consequence, the viability of bacteria after uptake could be affected. Bacterial uptake required actin polymerization, as shown by cytochalasin D inhibition, and it was partially bound to clathrin and caveolin dependent endocytosis. It also showed partial inhibition by ML7 indicating the involvement of cholesterol lipid rafts and myosin light chain kinase (MLCK) activation, at least in the LGG uptake by Caco-2. Most interestingly, bacteria remained viable inside the IEC for as long as 72 h without damaging the epithelial cells, and paracellular transcytosis was observed. These results stressed the fact that internalization of commensal and mutualistic bacteria is a natural, nonpathogenic process that may be relevant in crosstalk processes between the intestinal populations and the host, and future studies could determine its connection to processes such as commensal tolerance, resilience of microbial populations or transorganic bacterial migration.
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Dixit UG, Rodríguez NE, Polando R, McDowell MA, Wilson ME. Complement receptor 3 mediates ruffle-like, actin-rich aggregates during phagocytosis of Leishmania infantum metacyclics. Exp Parasitol 2021; 220:107968. [PMID: 32781093 PMCID: PMC7750307 DOI: 10.1016/j.exppara.2020.107968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 08/05/2020] [Accepted: 08/05/2020] [Indexed: 11/18/2022]
Abstract
The parasitic protozoan Leishmania infantum resides primarily in macrophages throughout mammalian infection. Infection is initiated by deposition of the metacyclic promastigote into the dermis of a mammalian host by the sand fly vector. Promastigotes enter macrophages by ligating surface receptors such as complement receptor 3 (CR3), inducing phagocytosis of the parasite. At the binding site of metacyclic promastigotes, we observed large asymmetrical aggregates of macrophage membrane with underlying actin, resembling membrane ruffles. Actin accumulation was observed at the point of initial contact, before phagosome formation and accumulation of peri-phagosomal actin. Ruffle-like structures did not form during phagocytosis of attenuated promastigotes or during phagocytosis of the intracellular amastigote form of L. infantum. Entry of promastigotes through massive actin accumulation was associated with a subsequent delay in fusion of the parasitophorous vacuole (PV) with the lysosomal markers LAMP-1 and Cathepsin D. Actin accumulation was also associated with entry through CR3, since macrophages from CD11b knockout (KO) mice did not form massive aggregates of actin during phagocytosis of metacyclic promastigotes. Furthermore, intracellular survival of L. infantum was significantly decreased in CD11b KO compared to wild type macrophages, although entry rates were similar. We conclude that both promastigote virulence and host cell CR3 are needed for the formation of ruffle-like membrane structures at the site of metacyclic promastigote phagocytosis, and that formation of actin-rich aggregates during entry correlates with the intracellular survival of virulent promastigotes.
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Affiliation(s)
- Upasna Gaur Dixit
- Department of Internal Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Nilda E Rodríguez
- Department of Biology, University of Northern Iowa, Cedar Falls, IA, 50614, USA.
| | - Rachel Polando
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Mary Ann McDowell
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Mary E Wilson
- Department of Internal Medicine, University of Iowa, Iowa City, IA, 52242, USA; Department of Microbiology and Immunology, University of Iowa, Iowa City, IA, 52242, USA; Veterans' Affairs Medical Center, Iowa City, IA, 52242, USA
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Multifaceted Functions of Host Cell Caveolae/Caveolin-1 in Virus Infections. Viruses 2020; 12:v12050487. [PMID: 32357558 PMCID: PMC7291293 DOI: 10.3390/v12050487] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 04/23/2020] [Accepted: 04/24/2020] [Indexed: 02/07/2023] Open
Abstract
Virus infection has drawn extensive attention since it causes serious or even deadly diseases, consequently inducing a series of social and public health problems. Caveolin-1 is the most important structural protein of caveolae, a membrane invagination widely known for its role in endocytosis and subsequent cytoplasmic transportation. Caveolae/caveolin-1 is tightly associated with a wide range of biological processes, including cholesterol homeostasis, cell mechano-sensing, tumorigenesis, and signal transduction. Intriguingly, the versatile roles of caveolae/caveolin-1 in virus infections have increasingly been appreciated. Over the past few decades, more and more viruses have been identified to invade host cells via caveolae-mediated endocytosis, although other known pathways have been explored. The subsequent post-entry events, including trafficking, replication, assembly, and egress of a large number of viruses, are caveolae/caveolin-1-dependent. Deprivation of caveolae/caveolin-1 by drug application or gene editing leads to abnormalities in viral uptake, viral protein expression, or virion release, whereas the underlying mechanisms remain elusive and must be explored holistically to provide potential novel antiviral targets and strategies. This review recapitulates our current knowledge on how caveolae/caveolin-1 functions in every step of the viral infection cycle and various relevant signaling pathways, hoping to provide a new perspective for future viral cell biology research.
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Caruana JC, Walper SA. Bacterial Membrane Vesicles as Mediators of Microbe - Microbe and Microbe - Host Community Interactions. Front Microbiol 2020; 11:432. [PMID: 32265873 PMCID: PMC7105600 DOI: 10.3389/fmicb.2020.00432] [Citation(s) in RCA: 137] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 03/02/2020] [Indexed: 01/18/2023] Open
Abstract
Bacterial membrane vesicles are proteoliposomal nanoparticles produced by both Gram-negative and Gram-positive bacteria. As they originate from the outer surface of the bacteria, their composition and content is generally similar to the parent bacterium’s membrane and cytoplasm. However, there is ample evidence that preferential packaging of proteins, metabolites, and toxins into vesicles does occur. Incorporation into vesicles imparts a number of benefits to the cargo, including protection from degradation by other bacteria, the host organism, or environmental factors, maintenance of a favorable microenvironment for enzymatic activity, and increased potential for long-distance movement. This enables vesicles to serve specialized functions tailored to changing or challenging environments, particularly in regard to microbial community interactions including quorum sensing, biofilm formation, antibiotic resistance, antimicrobial peptide expression and deployment, and nutrient acquisition. Additionally, based on their contents, vesicles play crucial roles in host-microbe interactions as carriers of virulence factors and other modulators of host cell function. Here, we discuss recent advances in our understanding of how vesicles function as signals both within microbial communities and between pathogenic or commensal microbes and their mammalian hosts. We also highlight a few areas that are currently ripe for additional research, including the mechanisms of selective cargo packaging into membrane vesicles and of cargo processing once it enters mammalian host cells, the function of vesicles in transfer of nucleic acids among bacteria, and the possibility of engineering commensal bacteria to deliver cargo of interest to mammalian hosts in a controlled manner.
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Affiliation(s)
- Julie C Caruana
- American Society for Engineering Education, Washington, DC, United States
| | - Scott A Walper
- US Naval Research Laboratory, Center for Biomolecular Science and Engineering, Washington, DC, United States
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Kumar GA, Karmakar J, Mandal C, Chattopadhyay A. Leishmania donovani Internalizes into Host Cells via Caveolin-mediated Endocytosis. Sci Rep 2019; 9:12636. [PMID: 31477757 PMCID: PMC6718660 DOI: 10.1038/s41598-019-49007-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 08/19/2019] [Indexed: 02/08/2023] Open
Abstract
Leishmania donovani is an intracellular protozoan parasite that causes visceral leishmaniasis, a major cause of mortality and morbidity worldwide. The host plasma membrane serves as the portal of entry for Leishmania to gain access to the cellular interior. Although several host cell membrane receptors have been shown to be involved in the entry of Leishmania donovani into host cells, the endocytic pathway involved in the internalization of the parasite is not known. In this work, we explored the endocytic pathway involved in the entry of Leishmania donovani into host macrophages, utilizing specific inhibitors against two major pathways of internalization, i.e., clathrin- and caveolin-mediated endocytosis. We show that pitstop 2, an inhibitor for clathrin-mediated endocytosis, does not affect the entry of Leishmania donovani promastigotes into host macrophages. Interestingly, a significant reduction in internalization was observed upon treatment with genistein, an inhibitor for caveolin-mediated endocytosis. These results are supported by a similar trend in intracellular amastigote load within host macrophages. These results suggest that Leishmania donovani utilizes caveolin-mediated endocytosis to internalize into host cells. Our results provide novel insight into the mechanism of phagocytosis of Leishmania donovani into host cells and assume relevance in the development of novel therapeutics against leishmanial infection.
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Affiliation(s)
- G Aditya Kumar
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, 500 007, India
| | - Joyshree Karmakar
- CSIR-Indian Institute of Chemical Biology, Raja S.C. Mullick Road, Kolkata, 700 032, India
| | - Chitra Mandal
- CSIR-Indian Institute of Chemical Biology, Raja S.C. Mullick Road, Kolkata, 700 032, India.
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Mehta N, Zhang D, Li R, Wang T, Gava A, Parthasarathy P, Gao B, Krepinsky JC. Caveolin-1 regulation of Sp1 controls production of the antifibrotic protein follistatin in kidney mesangial cells. Cell Commun Signal 2019; 17:37. [PMID: 30995923 PMCID: PMC6472091 DOI: 10.1186/s12964-019-0351-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 04/03/2019] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND We previously showed that caveolin-1 (cav-1), an integral membrane protein, is required for the synthesis of matrix proteins by glomerular mesangial cells (MC). In a previous study to understand how cav-1 is involved in regulating matrix production, we had identified significant upregulation of the antifibrotic protein follistatin in cav-1 knockout MC. Follistatin inhibits the profibrotic effects of several members of the transforming growth factor beta superfamily, in particular the activins. Here, we characterize the molecular mechanism through which cav-1 regulates the expression of follistatin. METHODS Kidneys from cav-1 wild type and knockout (KO) mice were analyzed and primary cultures of MC from cav-1 wild-type and KO mice were utilized. FST promoter deletion constructs were generated to determine the region of the promoter important for mediating FST upregulation in cav-1 KO MC. siRNA-mediated down-regulation and overexpression of Sp1 in conjunction with luciferase activity assays, immunoprecipitation, western blotting and ChiP was used to assess the role of Sp1 in transcriptionally regulating FST expression. Pharmacologic kinase inhibitors and specific siRNA were used to determine the post-translational mechanism through which cav-1 affects Sp1 activity. RESULTS Our results establish that follistatin upregulation occurs at the transcript level. We identified Sp1 as the critical transcription factor regulating activation of the FST promoter in cav-1 KO MC through binding to a region within 123 bp of the transcription start site. We further determined that the lack of cav-1 increases Sp1 nuclear levels and transcriptional activity. This occurred through increased phosphoinositide 3-kinase (PI3K) activity and downstream protein kinase C (PKC) zeta-mediated phosphorylation and activation of Sp1. CONCLUSIONS These findings shed light on the transcriptional mechanism by which cav-1 represses the expression of a major antifibrotic protein, and can inform the development of novel antifibrotic treatment strategies.
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Affiliation(s)
- Neel Mehta
- Division of Nephrology, Department of Medicine, McMaster University, Hamilton, Canada
| | - Dan Zhang
- Division of Nephrology, Department of Medicine, McMaster University, Hamilton, Canada
| | - Renzhong Li
- Division of Nephrology, Department of Medicine, McMaster University, Hamilton, Canada
| | - Tony Wang
- Division of Nephrology, Department of Medicine, McMaster University, Hamilton, Canada
| | - Agata Gava
- Physiological Sciences Graduate Program, Health Sciences Centre, Federal University of Espirito Santo, Vitoria, Brazil
| | | | - Bo Gao
- Division of Nephrology, Department of Medicine, McMaster University, Hamilton, Canada
| | - Joan C Krepinsky
- Division of Nephrology, Department of Medicine, McMaster University, Hamilton, Canada. .,St. Joseph's Hospital, 50 Charlton Ave East, Rm T3311, Hamilton, ON, L8N 4A6, Canada.
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Betanzos A, Zanatta D, Bañuelos C, Hernández-Nava E, Cuellar P, Orozco E. Epithelial Cells Expressing EhADH, An Entamoeba histolytica Adhesin, Exhibit Increased Tight Junction Proteins. Front Cell Infect Microbiol 2018; 8:340. [PMID: 30324093 PMCID: PMC6172307 DOI: 10.3389/fcimb.2018.00340] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 09/07/2018] [Indexed: 12/15/2022] Open
Abstract
In Entamoeba histolytica, the EhADH adhesin together with the EhCP112 cysteine protease, form a 124 kDa complex named EhCPADH. This complex participates in trophozoite adherence, phagocytosis and cytolysis of target cells. EhCPADH and EhCP112 are both involved on epithelium damage, by opening tight junctions (TJ) and reaching other intercellular junctions. EhADH is a scaffold protein belonging to the ALIX family that contains a Bro1 domain, expresses at plasma membrane, endosomes and cytoplasm of trophozoites, and is also secreted to the medium. Contribution of EhADH to TJ opening still remains unknown. In this paper, to elucidate the role of EhADH on epithelium injury, we followed two strategies: producing a recombinant protein (rEhADH) and transfecting the ehadh gene in MDCK cells. Results from the first strategy revealed that rEhADH reached the intercellular space of epithelial cells and co-localized with claudin-1 and occludin at TJ region; later, rEhADH was mainly internalized by clathrin-coated vesicles. In the second strategy, MDCK cells expressing EhADH (MDCK-EhADH) showed the adhesin at plasma membrane. In addition, MDCK-EHADH cells exhibited adhesive features, producing epithelial aggregation and adherence to erythrocytes, as described in trophozoites. Surprisingly, the adhesin expression produced an increase of claudin-1, occludin, ZO-1 and ZO-2 at TJ, and also the transepithelial electric resistance (TEER), which is a measure of TJ gate function. Moreover, MDCK-EhADH cells resulted more susceptible to trophozoites attack, as showed by TEER and cytopathic experiments. Overall, our results indicated that EhADH disturbed TJ from the extracellular space and also intracellularly, suggesting that EhADH affects by itself TJ proteins, and possibly synergizes the action of other parasite molecules during epithelial invasion.
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Affiliation(s)
- Abigail Betanzos
- Consejo Nacional de Ciencia y Tecnología, Mexico City, Mexico.,Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Dxinegueela Zanatta
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Cecilia Bañuelos
- Coordinación General de Programas de Posgrado Multidisciplinarios, Programa de Doctorado Transdisciplinario en Desarrollo Científico y Tecnológico para la Sociedad, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | | | - Patricia Cuellar
- Centro Regional de Educación Superior, Universidad Autónoma de Guerrero, Chilpancingo, Mexico
| | - Esther Orozco
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
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de Almeida CJG. Caveolin-1 and Caveolin-2 Can Be Antagonistic Partners in Inflammation and Beyond. Front Immunol 2017; 8:1530. [PMID: 29250058 PMCID: PMC5715436 DOI: 10.3389/fimmu.2017.01530] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 10/27/2017] [Indexed: 12/26/2022] Open
Abstract
Caveolins, encoded by the CAV gene family, are the main protein components of caveolae. In most tissues, caveolin-1 (Cav-1) and caveolin-2 (Cav-2) are co-expressed, and Cav-2 targeting to caveolae depends on the formation of heterooligomers with Cav-1. Notwithstanding, Cav-2 has unpredictable activities, opposing Cav-1 in the regulation of some cellular processes. While the major roles of Cav-1 as a modulator of cell signaling in inflammatory processes and in immune responses have been extensively discussed elsewhere, the aim of this review is to focus on data revealing the distinct activity of Cav-1 and Cav-2, which suggest that these proteins act antagonistically to fine-tune a variety of cellular processes relevant to inflammation.
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15
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Hernández-Nava E, Cuellar P, Nava P, Chávez-Munguía B, Schnoor M, Orozco E, Betanzos A. Adherens junctions and desmosomes are damaged by Entamoeba histolytica: Participation of EhCPADH complex and EhCP112 protease. Cell Microbiol 2017; 19. [PMID: 28656597 DOI: 10.1111/cmi.12761] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 05/08/2017] [Accepted: 06/22/2017] [Indexed: 12/31/2022]
Abstract
Entamoeba histolytica trophozoites adhere to epithelium at the cell-cell contact and perturb tight junctions disturbing the transepithelial electrical resistance. Behind tight junctions are the adherens junctions (AJs) that reinforce them and the desmosomes (DSMs) that maintain the epithelium integrity. The damage produced to AJs and DMSs by this parasite is unknown. Here, we studied the effect of the trophozoites, the EhCPADH complex, and the EhCP112 recombinant enzyme (rEhCP112) on AJ and DSM proteins. We found that trophozoites degraded β-cat, E-cad, Dsp l/ll, and Dsg-2 with the participation of EhCPADH and EhCP112. After contact of epithelial cells with trophozoites, immunofluorescence and transmission electron microscopy assays revealed EhCPADH and rEhCP112 at the intercellular space where they colocalised with β-cat, E-cad, Dsp l/ll, and Dsg-2. Moreover, our results suggested that rEhCP112 could be internalised by caveolae and clathrin-coated vesicles. Immunoprecipitation assays showed the interaction of EhCPADH with β-cat and Dsp l/ll. Besides, in vivo assays demonstrated that rEhCP112 concentrates at the cellular borders of the mouse intestine degrading E-cad and Dsp I/II. Our research gives the first clues on the trophozoite attack to AJs and DSMs and point out the role of the EhCPADH and EhCP112 in the multifactorial event of trophozoites virulence.
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Affiliation(s)
- Elizabeth Hernández-Nava
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Patricia Cuellar
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Porfirio Nava
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Bibiana Chávez-Munguía
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Michael Schnoor
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Esther Orozco
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Abigail Betanzos
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico.,Consejo Nacional de Ciencia y Tecnología, Mexico City, Mexico
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16
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Gilliam AJH, Smith JN, Flather D, Johnston KM, Gansmiller AM, Fishman DA, Edgar JM, Balk M, Majumdar S, Weiss GA. Affinity-Guided Design of Caveolin-1 Ligands for Deoligomerization. J Med Chem 2016; 59:4019-25. [PMID: 27010220 DOI: 10.1021/acs.jmedchem.5b01536] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Caveolin-1 is a target for academic and pharmaceutical research due to its many cellular roles and associated diseases. We report peptide WL47 (1), a small, high-affinity, selective disrupter of caveolin-1 oligomers. Developed and optimized through screening and analysis of synthetic peptide libraries, ligand 1 has 7500-fold improved affinity compared to its T20 parent ligand and an 80% decrease in sequence length. Ligand 1 will permit targeted study of caveolin-1 function.
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Affiliation(s)
- Amanda J H Gilliam
- Department of Chemistry, and ‡Department of Molecular Biology and Biochemistry, University of California , Irvine, California 92697-2025, United States
| | - Joshua N Smith
- Department of Chemistry, and ‡Department of Molecular Biology and Biochemistry, University of California , Irvine, California 92697-2025, United States
| | - Dylan Flather
- Department of Chemistry, and ‡Department of Molecular Biology and Biochemistry, University of California , Irvine, California 92697-2025, United States
| | - Kevin M Johnston
- Department of Chemistry, and ‡Department of Molecular Biology and Biochemistry, University of California , Irvine, California 92697-2025, United States
| | - Andrew M Gansmiller
- Department of Chemistry, and ‡Department of Molecular Biology and Biochemistry, University of California , Irvine, California 92697-2025, United States
| | - Dmitry A Fishman
- Department of Chemistry, and ‡Department of Molecular Biology and Biochemistry, University of California , Irvine, California 92697-2025, United States
| | - Joshua M Edgar
- Department of Chemistry, and ‡Department of Molecular Biology and Biochemistry, University of California , Irvine, California 92697-2025, United States
| | - Mark Balk
- Department of Chemistry, and ‡Department of Molecular Biology and Biochemistry, University of California , Irvine, California 92697-2025, United States
| | - Sudipta Majumdar
- Department of Chemistry, and ‡Department of Molecular Biology and Biochemistry, University of California , Irvine, California 92697-2025, United States
| | - Gregory A Weiss
- Department of Chemistry, and ‡Department of Molecular Biology and Biochemistry, University of California , Irvine, California 92697-2025, United States
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Kumar GA, Jafurulla M, Chattopadhyay A. The membrane as the gatekeeper of infection: Cholesterol in host-pathogen interaction. Chem Phys Lipids 2016; 199:179-185. [PMID: 26902688 DOI: 10.1016/j.chemphyslip.2016.02.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Revised: 02/13/2016] [Accepted: 02/15/2016] [Indexed: 11/30/2022]
Abstract
The cellular plasma membrane serves as a portal for the entry of intracellular pathogens. An essential step for an intracellular pathogen to gain entry into a host cell therefore is to be able to cross the cell membrane. In this review, we highlight the role of host membrane cholesterol in regulating the entry of intracellular pathogens using insights obtained from work on the interaction of Leishmania and Mycobacterium with host cells. The entry of these pathogens is known to be dependent on host membrane cholesterol. Importantly, pathogen entry is inhibited either upon depletion (or complexation), or enrichment of membrane cholesterol. In other words, an optimum level of host membrane cholesterol is necessary for efficient infection by pathogens. In this overall context, we propose a general mechanism, based on cholesterol-induced conformational changes, involving cholesterol binding sites in host cell surface receptors that are implicated in this process. A therapeutic strategy targeting modulation of membrane cholesterol would have the advantage of avoiding the commonly encountered problem of drug resistance in tackling infection by intracellular pathogens. Insights into the role of host membrane cholesterol in pathogen entry would be instrumental in the development of novel therapeutic strategies to effectively tackle intracellular pathogenesis.
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Affiliation(s)
- G Aditya Kumar
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
| | - Md Jafurulla
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
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18
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Goldmann O, Tuchscherr L, Rohde M, Medina E. α-Hemolysin enhances Staphylococcus aureus internalization and survival within mast cells by modulating the expression of β1 integrin. Cell Microbiol 2016; 18:807-19. [PMID: 26595647 DOI: 10.1111/cmi.12550] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Revised: 11/06/2015] [Accepted: 11/13/2015] [Indexed: 12/14/2022]
Abstract
Mast cells (MCs) are important sentinels of the host defence against invading pathogens. We previously reported that Staphylococcus aureus evaded the extracellular antimicrobial activities of MCs by promoting its internalization within these cells via β1 integrins. Here, we investigated the molecular mechanisms governing this process. We found that S. aureus responded to the antimicrobial mediators released by MCs by up-regulating the expression of α-hemolysin (Hla), fibronectin-binding protein A and several regulatory systems. We also found that S. aureus induced the up-regulation of β1 integrin expression on MCs and that this effect was mediated by Hla-ADAM10 (a disintegrin and metalloproteinase 10) interaction. Thus, deletion of Hla or inhibition of Hla-ADAM10 interaction significantly impaired S. aureus internalization within MCs. Furthermore, purified Hla but not the inactive HlaH35L induced up-regulation of β1 integrin expression in MCs in a dose-dependent manner. Our data support a model in which S. aureus counter-reacts the extracellular microbicidal mechanisms of MCs by increasing expression of fibronectin-binding proteins and by inducing Hla-ADAM10-mediated up-regulation of β1 integrin in MCs. The up-regulation of bacterial fibronectin-binding proteins, concomitantly with the increased expression of its receptor β1 integrin on the MCs, resulted in enhanced S. aureus internalization through the binding of fibronectin-binding proteins to integrin β1 via fibronectin.
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Affiliation(s)
- Oliver Goldmann
- Infection Immunology Research Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany
| | - Lorena Tuchscherr
- Institute of Medical Microbiology, University Hospital of Jena, Erlanger Allee 101, 07747, Jena, Germany
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany
| | - Eva Medina
- Infection Immunology Research Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany
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19
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Disruption of lipid rafts interferes with the interaction of Toxoplasma gondii with macrophages and epithelial cells. BIOMED RESEARCH INTERNATIONAL 2014; 2014:687835. [PMID: 24734239 PMCID: PMC3964738 DOI: 10.1155/2014/687835] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 12/26/2013] [Accepted: 01/08/2014] [Indexed: 12/02/2022]
Abstract
The intracellular parasite Toxoplasma gondii can penetrate any warm-blooded animal cell. Conserved molecular assemblies of host cell plasma membranes should be involved in the parasite-host cell recognition. Lipid rafts are well-conserved membrane microdomains that contain high concentrations of cholesterol, sphingolipids, glycosylphosphatidylinositol, GPI-anchored proteins, and dually acylated proteins such as members of the Src family of tyrosine kinases. Disturbing lipid rafts of mouse peritoneal macrophages and epithelial cells of the lineage LLC-MK2 with methyl-beta cyclodextrin (MβCD) and filipin, which interfere with cholesterol or lidocaine, significantly inhibited internalization of T. gondii in both cell types, although adhesion remained unaffected in macrophages and decreased only in LLC-MK2 cells. Scanning and transmission electron microscopy confirmed these observations. Results are discussed in terms of the original role of macrophages as professional phagocytes versus the LLC-MK2 cell lineage originated from kidney epithelial cells.
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20
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Abstract
Chagas heart disease, the leading cause of heart failure in Latin America, results from infection with the parasite Trypanosoma cruzi. Although T. cruzi disseminates intravascularly, how the parasite contends with the endothelial barrier to escape the bloodstream and infect tissues has not been described. Understanding the interaction between T. cruzi and the vascular endothelium, likely a key step in parasite dissemination, could inform future therapies to interrupt disease pathogenesis. We adapted systems useful in the study of leukocyte transmigration to investigate both the occurrence of parasite transmigration and its determinants in vitro. Here we provide the first evidence that T. cruzi can rapidly migrate across endothelial cells by a mechanism that is distinct from productive infection and does not disrupt monolayer integrity or alter permeability. Our results show that this process is facilitated by a known modulator of cellular infection and vascular permeability, bradykinin, and can be augmented by the chemokine CCL2. These represent novel findings in our understanding of parasite dissemination, and may help identify new therapeutic strategies to limit the dissemination of the parasite.
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21
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Hitkova I, Yuan G, Anderl F, Gerhard M, Kirchner T, Reu S, Röcken C, Schäfer C, Schmid RM, Vogelmann R, Ebert MPA, Burgermeister E. Caveolin-1 protects B6129 mice against Helicobacter pylori gastritis. PLoS Pathog 2013; 9:e1003251. [PMID: 23592983 PMCID: PMC3623771 DOI: 10.1371/journal.ppat.1003251] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Accepted: 02/04/2013] [Indexed: 02/07/2023] Open
Abstract
Caveolin-1 (Cav1) is a scaffold protein and pathogen receptor in the mucosa of the gastrointestinal tract. Chronic infection of gastric epithelial cells by Helicobacter pylori (H. pylori) is a major risk factor for human gastric cancer (GC) where Cav1 is frequently down-regulated. However, the function of Cav1 in H. pylori infection and pathogenesis of GC remained unknown. We show here that Cav1-deficient mice, infected for 11 months with the CagA-delivery deficient H. pylori strain SS1, developed more severe gastritis and tissue damage, including loss of parietal cells and foveolar hyperplasia, and displayed lower colonisation of the gastric mucosa than wild-type B6129 littermates. Cav1-null mice showed enhanced infiltration of macrophages and B-cells and secretion of chemokines (RANTES) but had reduced levels of CD25+ regulatory T-cells. Cav1-deficient human GC cells (AGS), infected with the CagA-delivery proficient H. pylori strain G27, were more sensitive to CagA-related cytoskeletal stress morphologies (“humming bird”) compared to AGS cells stably transfected with Cav1 (AGS/Cav1). Infection of AGS/Cav1 cells triggered the recruitment of p120 RhoGTPase-activating protein/deleted in liver cancer-1 (p120RhoGAP/DLC1) to Cav1 and counteracted CagA-induced cytoskeletal rearrangements. In human GC cell lines (MKN45, N87) and mouse stomach tissue, H. pylori down-regulated endogenous expression of Cav1 independently of CagA. Mechanistically, H. pylori activated sterol-responsive element-binding protein-1 (SREBP1) to repress transcription of the human Cav1 gene from sterol-responsive elements (SREs) in the proximal Cav1 promoter. These data suggested a protective role of Cav1 against H. pylori-induced inflammation and tissue damage. We propose that H. pylori exploits down-regulation of Cav1 to subvert the host's immune response and to promote signalling of its virulence factors in host cells. Infection with the bacterium Helicobacter pylori (H. pylori) mainly affects children in the developing countries who are at risk to progress to gastric cancer (GC) as adults after many years of persistent infection, especially with strains which are positive for the oncogenic virulence factor CagA. Eradication of H. pylori by antibiotics is a treatment of choice but may also alter the susceptibility to allergies and other tumor types. Thus, novel diagnostic or prognostic markers are needed which detect early molecular changes in the stomach mucosa during the transition of chronic inflammation to cancer. In our study, we found that the tumor suppressor caveolin-1 (Cav1) is reduced upon infection with H. pylori, and CagA was sufficient but not necessary for this down-regulation. Loss of Cav1 was caused by H. pylori-dependent activation of sterol-responsive element-binding protein-1 (SREBP1), and this event abolished the interaction of Cav1 with p120 RhoGTPase-activating protein/deleted in liver cancer-1 (p120RhoGAP/DLC1), a second bona fide tumor suppressor in gastric tissue. Conclusively, Cav1 and DLC1 may constitute novel molecular markers in the H. pylori-infected gastric mucosa before neoplastic transformation of the epithelium.
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Affiliation(s)
- Ivana Hitkova
- Department of Medicine II, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Gang Yuan
- Department of Gastroenterology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Florian Anderl
- Institute of Medical Microbiology, Immunology and Hygiene, Technische Universität München, München, Germany
| | - Markus Gerhard
- Institute of Medical Microbiology, Immunology and Hygiene, Technische Universität München, München, Germany
- German Centre for Infection Research (DZIF), München, Germany
| | - Thomas Kirchner
- Institute of Pathology, Klinikum der Universität München, München, Germany
| | - Simone Reu
- Institute of Pathology, Klinikum der Universität München, München, Germany
| | - Christoph Röcken
- Department of Pathology, Christian-Albrechts Universität, Kiel, Germany
| | - Claus Schäfer
- Department of Medicine II, Klinikum der Universität München, München, Germany
| | - Roland M. Schmid
- Department of Medicine II, Klinikum rechts der Isar, Technische Universität München, München, Germany
| | - Roger Vogelmann
- Department of Medicine II, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Matthias P. A. Ebert
- Department of Medicine II, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Elke Burgermeister
- Department of Medicine II, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- * E-mail:
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