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Chen XN, Liang YF, Weng ZJ, Quan WP, Hu C, Peng YZ, Sun YS, Gao Q, Huang Z, Zhang GH, Gong L. Porcine Enteric Alphacoronavirus Entry through Multiple Pathways (Caveolae, Clathrin, and Macropinocytosis) Requires Rab GTPases for Endosomal Transport. J Virol 2023; 97:e0021023. [PMID: 36975780 PMCID: PMC10134835 DOI: 10.1128/jvi.00210-23] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 03/07/2023] [Indexed: 03/29/2023] Open
Abstract
Porcine enteric alphacoronavirus (PEAV) is a new bat HKU2-like porcine coronavirus, and its endemic outbreak has caused severe economic losses to the pig industry. Its broad cellular tropism suggests a potential risk of cross-species transmission. A limited understanding of PEAV entry mechanisms may hinder a rapid response to potential outbreaks. This study analyzed PEAV entry events using chemical inhibitors, RNA interference, and dominant-negative mutants. PEAV entry into Vero cells depended on three endocytic pathways: caveolae, clathrin, and macropinocytosis. Endocytosis requires dynamin, cholesterol, and a low pH. Rab5, Rab7, and Rab9 GTPases (but not Rab11) regulate PEAV endocytosis. PEAV particles colocalize with EEA1, Rab5, Rab7, Rab9, and Lamp-1, suggesting that PEAV translocates into early endosomes after internalization, and Rab5, Rab7, and Rab9 regulate trafficking to lysosomes before viral genome release. PEAV enters porcine intestinal cells (IPI-2I) through the same endocytic pathway, suggesting that PEAV may enter various cells through multiple endocytic pathways. This study provides new insights into the PEAV life cycle. IMPORTANCE Emerging and reemerging coronaviruses cause severe human and animal epidemics worldwide. PEAV is the first bat-like coronavirus to cause infection in domestic animals. However, the PEAV entry mechanism into host cells remains unknown. This study demonstrates that PEAV enters into Vero or IPI-2I cells through caveola/clathrin-mediated endocytosis and macropinocytosis, which does not require a specific receptor. Subsequently, Rab5, Rab7, and Rab9 regulate PEAV trafficking from early endosomes to lysosomes, which is pH dependent. The results advance our understanding of the disease and help to develop potential new drug targets against PEAV.
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Affiliation(s)
- Xiong-nan Chen
- Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, People’s Republic of China
- Guangdong Provincial Key Laboratory of Utilization and Conservation of Food and Medicinal Resources in Northern Region, Shaoguan University, Shaoguan, People’s Republic of China
- Maoming Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong, People’s Republic of China
| | - Yi-fan Liang
- Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, People’s Republic of China
- Maoming Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong, People’s Republic of China
| | - Zhi-jun Weng
- Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, People’s Republic of China
- Maoming Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong, People’s Republic of China
| | - Wei-peng Quan
- Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, People’s Republic of China
- Key Laboratory of Animal Vaccine Development, Ministry of Agriculture and Rural Affairs, People’s Republic of China
| | - Chen Hu
- Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, People’s Republic of China
| | - Yun-zhao Peng
- Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, People’s Republic of China
- Key Laboratory of Animal Vaccine Development, Ministry of Agriculture and Rural Affairs, People’s Republic of China
| | - Ying-shuo Sun
- Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, People’s Republic of China
- Maoming Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong, People’s Republic of China
| | - Qi Gao
- Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, People’s Republic of China
- Maoming Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong, People’s Republic of China
| | - Zhao Huang
- Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, People’s Republic of China
- Guangdong Provincial Key Laboratory of Utilization and Conservation of Food and Medicinal Resources in Northern Region, Shaoguan University, Shaoguan, People’s Republic of China
- Maoming Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong, People’s Republic of China
| | - Gui-hong Zhang
- Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, People’s Republic of China
- Maoming Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong, People’s Republic of China
- Key Laboratory of Animal Vaccine Development, Ministry of Agriculture and Rural Affairs, People’s Republic of China
- National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou, People’s Republic of China
| | - Lang Gong
- Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, People’s Republic of China
- Maoming Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong, People’s Republic of China
- Key Laboratory of Animal Vaccine Development, Ministry of Agriculture and Rural Affairs, People’s Republic of China
- National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou, People’s Republic of China
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Charla R, Patil PP, Patil VS, Bhandare VV, Karoshi V, Balaganur V, Joshi RK, Harish DR, Roy S. Anti-Cholera toxin activity of selected polyphenols from Careya arborea, Punica granatum, and Psidium guajava. Front Cell Infect Microbiol 2023; 13:1106293. [PMID: 37113136 PMCID: PMC10126245 DOI: 10.3389/fcimb.2023.1106293] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 02/28/2023] [Indexed: 04/29/2023] Open
Abstract
Introduction Careya arborea, Punica granatum, and Psidium guajava are traditionally used to treat diarrheal diseases in India and were reported to show anti-Cholera toxin activity from our earlier studies. As polyphenols are reported to neutralize Cholera toxin (CT), the present study investigated the inhibitory activity of selected polyphenols from these plants against CTB binding to GM1 receptor using in silico, in vitro, and in vivo approaches. Methods Molecular modelling approach was used to investigate the intermolecular interactions of selected 20 polyphenolic compounds from three plants with CT using DOCK6. Based on intermolecular interactions, two phenolic acids, Ellagic acid (EA) and Chlorogenic acid (CHL); two flavonoids, Rutin (RTN) and Phloridzin (PHD) were selected along with their respective standards, Gallic acid (GA) and Quercetrin (QRTN). The stability of docked complexes was corroborated using molecular dynamics simulation. Furthermore, in vitro inhibitory activity of six compounds against CT was assessed using GM1 ELISA and cAMP assay. EA and CHL that showed prominent activity against CT in in vitro assays were investigated for their neutralizing activity against CT-induced fluid accumulation and histopathological changes in adult mouse. Results and discussion The molecular modelling study revealed significant structural stability of the CT-EA, CT-CHL, and CT-PHD complexes compared to their respective controls. All the selected six compounds significantly reduced CT-induced cAMP levels, whereas EA, CHL, and PHD exhibited > 50% binding inhibition of CT to GM1. The EA and CHL that showed prominent neutralization activity against CT from in vitro studies, also significantly decreased CT-induced fluid accumulation and histopathological changes in adult mouse. Our study identified bioactive compounds from these three plants against CT-induced diarrhea.
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Affiliation(s)
- Rajitha Charla
- Indian Council of Medical Research - National Institute of Traditional Medicine, Belagavi, Karnataka, India
- KLE Academy of Higher Education and Research (KAHER), Belagavi, India
| | - Priyanka P. Patil
- Indian Council of Medical Research - National Institute of Traditional Medicine, Belagavi, Karnataka, India
- KLE Academy of Higher Education and Research (KAHER), Belagavi, India
| | - Vishal S. Patil
- Indian Council of Medical Research - National Institute of Traditional Medicine, Belagavi, Karnataka, India
- KLE Academy of Higher Education and Research (KAHER), Belagavi, India
| | - Vishwambhar V. Bhandare
- Indian Council of Medical Research - National Institute of Traditional Medicine, Belagavi, Karnataka, India
- Department of Microbiology, Shivaji University, Kolhapur, India
| | - Veeresh Karoshi
- Indian Council of Medical Research - National Institute of Traditional Medicine, Belagavi, Karnataka, India
| | - Venkanna Balaganur
- Indian Council of Agricultural Research – Krishi Vigyan Kendra, Bagalkot, Karnataka, India
- University of Agricultural Sciences, Dharwad, Karnataka, India
| | - Rajesh K. Joshi
- Indian Council of Medical Research - National Institute of Traditional Medicine, Belagavi, Karnataka, India
| | - Darasaguppe R. Harish
- Indian Council of Medical Research - National Institute of Traditional Medicine, Belagavi, Karnataka, India
- *Correspondence: Darasaguppe R. Harish, ; Subarna Roy,
| | - Subarna Roy
- Indian Council of Medical Research - National Institute of Traditional Medicine, Belagavi, Karnataka, India
- *Correspondence: Darasaguppe R. Harish, ; Subarna Roy,
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White C, Bader C, Teter K. The manipulation of cell signaling and host cell biology by cholera toxin. Cell Signal 2022; 100:110489. [PMID: 36216164 PMCID: PMC10082135 DOI: 10.1016/j.cellsig.2022.110489] [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: 09/11/2022] [Accepted: 10/01/2022] [Indexed: 11/03/2022]
Abstract
Vibrio cholerae colonizes the small intestine and releases cholera toxin into the extracellular space. The toxin binds to the apical surface of the epithelium, is internalized into the host endomembrane system, and escapes into the cytosol where it activates the stimulatory alpha subunit of the heterotrimeric G protein by ADP-ribosylation. This initiates a cAMP-dependent signaling pathway that stimulates chloride efflux into the gut, with diarrhea resulting from the accompanying osmotic movement of water into the intestinal lumen. G protein signaling is not the only host system manipulated by cholera toxin, however. Other cellular mechanisms and signaling pathways active in the intoxication process include endocytosis through lipid rafts, retrograde transport to the endoplasmic reticulum, the endoplasmic reticulum-associated degradation system for protein delivery to the cytosol, the unfolded protein response, and G protein de-activation through degradation or the function of ADP-ribosyl hydrolases. Although toxin-induced chloride efflux is thought to be an irreversible event, alterations to these processes could facilitate cellular recovery from intoxication. This review will highlight how cholera toxin exploits signaling pathways and other cell biology events to elicit a diarrheal response from the host.
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Affiliation(s)
- Christopher White
- Burnett School of Biomedical Sciences, 12722 Research Parkway, University of Central Florida, Orlando, FL 32826, USA.
| | - Carly Bader
- Burnett School of Biomedical Sciences, 12722 Research Parkway, University of Central Florida, Orlando, FL 32826, USA.
| | - Ken Teter
- Burnett School of Biomedical Sciences, 12722 Research Parkway, University of Central Florida, Orlando, FL 32826, USA.
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Yuan L, Zhao Y, Sun XL. Sialidase substrates for Sialdiase assays - activity, specificity, quantification and inhibition. Glycoconj J 2020; 37:513-531. [PMID: 32813176 DOI: 10.1007/s10719-020-09940-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/08/2020] [Accepted: 08/06/2020] [Indexed: 12/01/2022]
Abstract
Sialidases are glycosidases responsible for the removal of sialic acid (Sia) residues (desialylation) from glycan portions of either glycoproteins or glycolipids. By desialylation, sialidases are able to modulate the functionality and stability of the Sia-containing molecules and are involved in both physiological and pathological pathways. Therefore, evaluation of sialidase activity and specificity is important for understanding the biological significance of desialylation by sialidases and its function and the related molecular mechanisms of the physiological and pathological pathways. In addition, it is essential for developing novel mechanisms and approaches for disease treatment and diagnosis and pathogen detection as well. This review summarizes the most recent sialidase substrates for evaluating sialidase activity and specificity and screening sialidase inhibitors, including (i) general sialidase substrates, (ii) specific sialidase substrates, (iii) native sialidase substrates and (iv) cellular sialidase substrates. This review also provides a brief introduction of recent instrumental methods for quantifying the sialidase activity, such as UV, fluorescence, HPLC and LC-MS methods.
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Affiliation(s)
- Lei Yuan
- Department of Chemistry, Chemical and Biomedical Engineering and Center for Gene Regulation in Health and Disease (GRHD), Cleveland State University, 2121 Euclid Avenue, Cleveland, OH, 44115, USA.,School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang, 110016, People's Republic of China
| | - Yu Zhao
- Department of Chemistry, Chemical and Biomedical Engineering and Center for Gene Regulation in Health and Disease (GRHD), Cleveland State University, 2121 Euclid Avenue, Cleveland, OH, 44115, USA
| | - Xue-Long Sun
- Department of Chemistry, Chemical and Biomedical Engineering and Center for Gene Regulation in Health and Disease (GRHD), Cleveland State University, 2121 Euclid Avenue, Cleveland, OH, 44115, USA.
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Cervin J, Boucher A, Youn G, Björklund P, Wallenius V, Mottram L, Sampson NS, Yrlid U. Fucose-Galactose Polymers Inhibit Cholera Toxin Binding to Fucosylated Structures and Galactose-Dependent Intoxication of Human Enteroids. ACS Infect Dis 2020; 6:1192-1203. [PMID: 32134631 PMCID: PMC7227030 DOI: 10.1021/acsinfecdis.0c00009] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
![]()
A promising strategy to limit cholera
severity involves blockers
mimicking the canonical cholera toxin ligand (CT) ganglioside GM1.
However, to date the efficacies of most of these blockers have been
evaluated in noncellular systems that lack ligands other than GM1.
Importantly, the CT B subunit (CTB) has a noncanonical site that binds
fucosylated structures, which in contrast to GM1 are highly expressed
in the human intestine. Here we evaluate the capacity of norbornene
polymers displaying galactose and/or fucose to block CTB binding to
immobilized protein-linked glycan structures and also to primary human
and murine small intestine epithelial cells (SI ECs). We show that
the binding of CTB to human SI ECs is largely dependent on the noncanonical
binding site, and interference with the canonical site has a limited
effect while the opposite is observed with murine SI ECs. The galactose–fucose
polymer blocks binding to fucosylated glycans but not to GM1. However,
the preincubation of CT with the galactose–fucose polymer only
partially blocks toxic effects on cultured human enteroid cells, while
preincubation with GM1 completely blocks CT-mediated secretion. Our
results support a model whereby the binding of fucose to the noncanonical
site places CT in close proximity to scarcely expressed galactose
receptors such as GM1 to enable binding via the canonical site leading
to CT internalization and intoxication. Our finding also highlights
the importance of complementing CTB binding studies with functional
intoxication studies when assessing the efficacy inhibitors of CT.
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Affiliation(s)
- Jakob Cervin
- Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Andrew Boucher
- Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Gyusaang Youn
- Department of Chemistry, Stony Brook University, Stony Brook, New York, 11794-3400, United States
| | - Per Björklund
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Sahlgrenska University Hospital/Östra, 416 85 Gothenburg, Sweden
| | - Ville Wallenius
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Sahlgrenska University Hospital/Östra, 416 85 Gothenburg, Sweden
| | - Lynda Mottram
- Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Nicole S. Sampson
- Department of Chemistry, Stony Brook University, Stony Brook, New York, 11794-3400, United States
| | - Ulf Yrlid
- Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, 405 30 Gothenburg, Sweden
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Investigation of substrate specificity of sialidases with membrane mimetic glycoconjugates. Glycoconj J 2019; 37:175-185. [PMID: 31802374 DOI: 10.1007/s10719-019-09895-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 10/20/2019] [Accepted: 11/06/2019] [Indexed: 01/17/2023]
Abstract
Sialidases or neuraminidases play important roles in various physiological and pathological processes by cleaving terminal sialic acids (Sias) (desialylation) from the glycans of both glycoproteins and glycolipids. To understand the biological significance of desialylation by sialidases, it is important to investigate enzyme specificity with native substrate in biological membrane of cells. Herein, we report a membrane-mimicking system with liposome ganglioside conjugates containing different lipids for evaluating substrate specificity of sialidase and the lipid effect on the enzyme activity. Briefly, liposomes of phosphatidylcholine (PC) and cholesterol with ganglioside (GM3 or GM1) along with different percentage of phosphatidylserine (PS) or phosphatidylethanolamine (PE) were prepared and characterized. Their desialylation profiles with Arthrobacter ureafaciens (bacterial) sialidase and H1N1 (influenza viral) sialidase were quantified by HPLC method. A diversity of substrate preference was found for both bacterial and viral sialidase to the liposome ganglioside conjugate platform. The apparent Km and Vmax were dependent on the type of lipid. These results indicate that the intrinsic characteristics of the membrane-like system affect the sialidase specificity and activity. This biomimetic substrate provides a better tool for unravelling the substrate specificity and the biological function of sialidases and for screening of functional sialidase inhibitors as well.
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Melkoumov A, St-Jean I, Banquy X, Leclair G, Leblond Chain J. GM1-Binding Conjugates To Improve Intestinal Permeability. Mol Pharm 2018; 16:60-70. [PMID: 30422668 DOI: 10.1021/acs.molpharmaceut.8b00776] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Drugs and proteins with poor intestinal permeability have a limited oral bioavailability. To remediate this problem, a receptor-mediated endocytosis and transcytosis approach was explored. Indeed, the nontoxic β subunit of cholera toxin (CTB) can cross the intestinal barrier by binding to receptor GM1. In this study, we explored the use of GM1-binding peptides and CTB as potential covalent carriers of poorly permeable molecules. GM1-binding peptides (G23, P3) and CTB were conjugated to poorly permeable fluorescent probes such as fluorescein isothiocyanate (FITC) and albumin-FITC using triethylene glycol spacers and click chemistry. The affinity of the peptide conjugates with receptor GM1 was confirmed by isothermal titration calorimetry or microscale thermophoresis, and the results suggested the involvement of nonspecific interactions. Conjugating the model drugs to G23 and P3 improved the internalization into Caco-2 and T84 cells, although the process was not dependent on the amount of GM1 receptor. However, conjugation of bovine serum albumin FITC to CTB increased the internalization in the same cells in a GM1-dependent pathway. Peptide conjugates demonstrated a limited permeability through a Caco-2 monolayer, whereas G23 and CTB conjugates slightly enhanced permeability through a T84 cell monolayer compared to model drugs alone. Since CTB can improve the permeability of large macromolecules such as albumin, it is an interesting carrier for the improvement of oral bioavailability of various other macromolecules such as heparins, proteins, and siRNAs.
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Affiliation(s)
- Alexandre Melkoumov
- Faculty of Pharmacy , Université de Montréal , H3C 3J7 Montréal , Québec , Canada
| | - Isabelle St-Jean
- Faculty of Pharmacy , Université de Montréal , H3C 3J7 Montréal , Québec , Canada
| | - Xavier Banquy
- Faculty of Pharmacy , Université de Montréal , H3C 3J7 Montréal , Québec , Canada
| | - Grégoire Leclair
- Faculty of Pharmacy , Université de Montréal , H3C 3J7 Montréal , Québec , Canada
| | - Jeanne Leblond Chain
- Faculty of Pharmacy , Université de Montréal , H3C 3J7 Montréal , Québec , Canada
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8
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Lee D, Mohr A, Kwon JSI, Wu HJ. Kinetic Monte Carlo modeling of multivalent binding of CTB proteins with GM1 receptors. Comput Chem Eng 2018. [DOI: 10.1016/j.compchemeng.2018.08.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Hunter CD, Guo T, Daskhan G, Richards MR, Cairo CW. Synthetic Strategies for Modified Glycosphingolipids and Their Design as Probes. Chem Rev 2018; 118:8188-8241. [DOI: 10.1021/acs.chemrev.8b00070] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Carmanah D. Hunter
- Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Tianlin Guo
- Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Gour Daskhan
- Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Michele R. Richards
- Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Christopher W. Cairo
- Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
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Zanetti C, Gallina A, Fabbri A, Parisi S, Palermo A, Fecchi K, Boussadia Z, Carollo M, Falchi M, Pasquini L, Fiani ML, Sargiacomo M. Cell Propagation of Cholera Toxin CTA ADP-Ribosylating Factor by Exosome Mediated Transfer. Int J Mol Sci 2018; 19:E1521. [PMID: 29783743 PMCID: PMC5983816 DOI: 10.3390/ijms19051521] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Revised: 05/15/2018] [Accepted: 05/16/2018] [Indexed: 12/15/2022] Open
Abstract
In this study, we report how the cholera toxin (CT) A subunit (CTA), the enzyme moiety responsible for signaling alteration in host cells, enters the exosomal pathway, secretes extracellularly, transmits itself to a cell population. The first evidence for long-term transmission of CT's toxic effect via extracellular vesicles was obtained in Chinese hamster ovary (CHO) cells. To follow the CT intracellular route towards exosome secretion, we used a novel strategy for generating metabolically-labeled fluorescent exosomes that can be counted by flow cytometry assay (FACS) and characterized. Our results clearly show the association of CT with exosomes, together with the heat shock protein 90 (HSP90) and Protein Disulfide Isomerase (PDI) molecules, proteins required for translocation of CTA across the ER membrane into the cytoplasm. Confocal microscopy showed direct internalization of CT containing fluorescent exo into CHO cells coupled with morphological changes in the recipient cells that are characteristic of CT action. Moreover, Me665 cells treated with CT-containing exosomes showed an increase in Adenosine 3',5'-Cyclic Monophosphate (cAMP) level, reaching levels comparable to those seen in cells exposed directly to CT. Our results prompt the idea that CT can exploit an exosome-mediated cell communication pathway to extend its pathophysiological action beyond an initial host cell, into a multitude of cells. This finding could have implications for cholera disease pathogenesis and epidemiology.
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Affiliation(s)
- Cristiana Zanetti
- Department of Oncology and Molecular Medicine, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Angelo Gallina
- Department of Neurosciences, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Alessia Fabbri
- National Center for Global Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Sofia Parisi
- National Center for Global Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Angela Palermo
- National Center for Global Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Katia Fecchi
- National Center for Global Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Zaira Boussadia
- National Center for Global Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Maria Carollo
- Core Facilities⁻Cytometry Unit, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Mario Falchi
- National AIDS Center, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Luca Pasquini
- Core Facilities⁻Cytometry Unit, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Maria Luisa Fiani
- National Center for Global Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Massimo Sargiacomo
- National Center for Global Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
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The anti-tumor drug 2-hydroxyoleic acid (Minerval) stimulates signaling and retrograde transport. Oncotarget 2018; 7:86871-86888. [PMID: 27894086 PMCID: PMC5349960 DOI: 10.18632/oncotarget.13508] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 10/17/2016] [Indexed: 11/25/2022] Open
Abstract
2-hydroxyoleic acid (OHOA, Minerval®) is an example of a substance used for membrane lipid therapy, where the cellular membranes rather than specific proteins constitute the therapeutical target. OHOA is thought to mediate its anti-tumor effect by affecting the biophysical properties of membranes, which leads to altered recruitment and activation of amphitropic proteins, altered cellular signaling, and eventual cell death. Little is known about the initial signaling events upon treatment with OHOA, and whether the altered membrane properties would have any impact on the dynamic intracellular transport system. In the present study we demonstrate that treatment with OHOA led to a rapid release of intracellular calcium and activation of multiple signaling pathways in HeLa cells, including the PI3K-AKT1-MTOR pathway and several MAP kinases, in a process independent of the EGFR. By lipidomics we confirmed that OHOA was incorporated into several lipid classes. Concomitantly, OHOA potently increased retrograde transport of the plant toxin ricin from endosomes to the Golgi and further to the endoplasmic reticulum. The OHOA-stimulated ricin transport seemed to require several amphitropic proteins, including Src, phospholipase C, protein kinase C, and also Ca2+/calmodulin. Interestingly, OHOA induced a slight increase in endosomal localization of the retromer component VPS35. Thus, our data show that addition of a lipid known to alter membrane properties not only affects signaling, but also intracellular transport.
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Kabbani AM, Kelly CV. Nanoscale Membrane Budding Induced by CTxB and Detected via Polarized Localization Microscopy. Biophys J 2017; 113:1795-1806. [PMID: 29045873 DOI: 10.1016/j.bpj.2017.08.031] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 08/07/2017] [Accepted: 08/11/2017] [Indexed: 11/17/2022] Open
Abstract
For endocytosis and exocytosis, membranes transition among planar, budding, and vesicular topographies through nanoscale reorganization of lipids, proteins, and carbohydrates. However, prior attempts to understand the initial stages of nanoscale bending have been limited by experimental resolution. Through the implementation of polarized localization microscopy, this article reports the inherent membrane bending capability of cholera toxin subunit B (CTxB) in quasi-one-component-supported lipid bilayers. Membrane buds were first detected with <50 nm radius, grew to >200 nm radius, and extended into longer tubules with dependence on the membrane tension and CTxB concentration. Compared to the concentration of the planar-supported lipid bilayers, CTxB was (12 ± 4)× more concentrated on the positive curvature top and (26 ± 11)× more concentrated on the negative Gaussian curvature neck of the nanoscale membrane buds. CTxB is frequently used as a marker for liquid-ordered lipid phases; however, the coupling between CTxB and membrane bending provides an alternate understanding of CTxB-induced membrane reorganization. These findings allow for the reinterpretation of prior observations by correlating CTxB clustering and diffusion to CTxB-induced membrane bending. Single-particle tracking was performed on single lipids and CTxB to reveal the correlations among single-molecule diffusion, CTxB accumulation, and membrane topography. Slowed lipid and CTxB diffusion was observed at the nanoscale bud locations, suggesting a local increase in the effective membrane viscosity or molecular crowding upon membrane bending. These results suggest inherent CTxB-induced membrane bending as a mechanism for initiating CTxB internalization in cells that could be independent of clathrin, caveolin, actin, and lipid phase separation.
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Affiliation(s)
- Abir M Kabbani
- Department of Physics and Astronomy, Wayne State University, Detroit, Michigan
| | - Christopher V Kelly
- Department of Physics and Astronomy, Wayne State University, Detroit, Michigan.
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13
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Van Blerkom J, Zimmermann S. Ganglioside-enriched microdomains define an oolemma that is functionally polarized with respect to fertilizability in the mouse. Reprod Biomed Online 2016; 33:458-475. [DOI: 10.1016/j.rbmo.2016.06.029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 06/17/2016] [Accepted: 06/29/2016] [Indexed: 10/21/2022]
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14
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Abstract
Apoptosis triggered by ricin toxin (RT) has previously been associated with certain cellular organellar compartments, but the diversity in the composition of the organellar proteins remains unclear. Here, we applied a shotgun proteomics strategy to examine the differential expression of proteins in the mitochondria, nuclei, and cytoplasm of HeLa cells treated and not treated with RT. Data were combined with a global bioinformatics analysis and experimental confirmations. A total of 3107 proteins were identified. Bioinformatics predictors (Proteome Analyst, WoLF PSORT, TargetP, MitoPred, Nucleo, MultiLoc, and k-nearest neighbor) and a Bayesian model that integrated these predictors were used to predict the locations of 1349 distinct organellar proteins. Our data indicate that the Bayesian model was more efficient than the individual implementation of these predictors. Additionally, a Biomolecular Interaction Network (BIN) analysis was used to identify 149 BIN subnetworks. Our experimental confirmations indicate that certain apoptosis-related proteins (e.g. cytochrome c, enolase, lamin B, Bax, and Drp1) were found to be translocated and had variable expression levels. These results provide new insights for the systematic understanding of RT-induced apoptosis responses.
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Affiliation(s)
- Peng Liao
- Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan Province, People's Republic of China Institute of Military Veterinary Science, Academy of Military Medical Science, Changchun, Jilin Province, People's Republic of China
| | - Yunhu Li
- Hunan Biological and Electromechanical Polytechnic, The Party and Government Office, Changsha, Hunan Province, People's Republic of China
| | - Hongyang Li
- Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan Province, People's Republic of China
| | - Wensen Liu
- Institute of Military Veterinary Science, Academy of Military Medical Science, Changchun, Jilin Province, People's Republic of China
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15
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Malanga M, Szemán J, Fenyvesi É, Puskás I, Csabai K, Gyémánt G, Fenyvesi F, Szente L. "Back to the Future": A New Look at Hydroxypropyl Beta-Cyclodextrins. J Pharm Sci 2016; 105:2921-2931. [PMID: 27317368 DOI: 10.1016/j.xphs.2016.04.034] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 04/29/2016] [Accepted: 04/29/2016] [Indexed: 12/14/2022]
Abstract
Since the discovery about 30 years ago (2-hydroxypropyl) beta-cyclodextrin, a highly soluble derivative of beta-cyclodextrin, has become an approved excipient of drug formulations included both in the United States and European Pharmacopoeias. It is recommended to use as solubilizer and stabilizer for oral and parenteral formulations. Recently, its pharmacological activity has been recognized in various diseases. The increasing applications require a closer look to the structure-activity relationship. As (2-hydroxypropyl) beta-cyclodextrin (HPBCD) is always a mixture of isomers with various degrees and pattern of hydroxypropylation, no wonder that the products of different manufacturers are often different. Several HPBCDs were compared applying a battery of analytical tools including thin layer chromatography, high performance liquid chromatography (HPLC), HPLC-mass spectrometry (MS), and matrix-assisted laser desorption MS. We studied how the average degree of substitution affects the aggregation behavior, the toxicity, and the solubilizing effect on poorly soluble drugs. We found that the products with low average degree of substitution are more prone to aggregation. The samples studied are nontoxic to Caco-2 cells and have low hemolytic activity. The solubility enhancement of poorly soluble drugs decreases or increases with increasing degree of substitution or shows a maximum curve depending on the properties of the guest.
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Affiliation(s)
- Milo Malanga
- CycloLab Cyclodextrin Research & Development Ltd, Budapest, Hungary H-1097
| | - Julianna Szemán
- CycloLab Cyclodextrin Research & Development Ltd, Budapest, Hungary H-1097
| | - Éva Fenyvesi
- CycloLab Cyclodextrin Research & Development Ltd, Budapest, Hungary H-1097.
| | - István Puskás
- CycloLab Cyclodextrin Research & Development Ltd, Budapest, Hungary H-1097
| | - Katalin Csabai
- CycloLab Cyclodextrin Research & Development Ltd, Budapest, Hungary H-1097
| | - Gyöngyi Gyémánt
- Inorganic and Analytical Chemistry, Faculty of Sciences and Technology, University of Debrecen, Hungary, H-4032
| | - Ferenc Fenyvesi
- Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Debrecen, Debrecen, Hungary
| | - Lajos Szente
- CycloLab Cyclodextrin Research & Development Ltd, Budapest, Hungary H-1097
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16
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Vibrio vulnificus VvhA induces autophagy-related cell death through the lipid raft-dependent c-Src/NOX signaling pathway. Sci Rep 2016; 6:27080. [PMID: 27250250 PMCID: PMC4890043 DOI: 10.1038/srep27080] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 05/15/2016] [Indexed: 12/22/2022] Open
Abstract
VvhA, a virulent factor of Vibrio (V.) vulnificus, induces acute cell death in a destructive manner. Autophagy plays an important role in cell death, but the functional role of VvhA in autophagy-related cell death has not been elucidated yet. We found that rVvhA significantly increased LC3 puncta formation and autophagic flux in promoting the cell death of human intestinal epithelial Caco-2 cells. The cell death induced by rVvhA was independent of lysosomal permeabilizaton and caspase activation. rVvhA induced rapid phosphorylation of c-Src in the membrane lipid raft, which resulted in an increased interaction between lipid raft molecule caveolin-1 and NADPH oxidase (NOX) complex Rac1 for ROS production. NOX-mediated ROS signaling induced by rVvhA increased the phosphorylation of extracellular signal-regulated kinase (ERK) and eukaryotic translation initiation factor 2α (eIF2α) which are required for mRNA expression of Atg5 and Atg16L1 involved in autophagosome formation. In an in vivo model, VvhA increased autophagy activation and paracellular permeabilization in intestinal epithelium. Collectively, the results here show that VvhA plays a pivotal role in the pathogenesis and dissemination of V. vulnificus by autophagy upregulation, through the lipid raft-mediated c-Src/NOX signaling pathway and ERK/eIF2α activation.
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17
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Mercier V, Laporte MH, Destaing O, Blot B, Blouin CM, Pernet-Gallay K, Chatellard C, Saoudi Y, Albiges-Rizo C, Lamaze C, Fraboulet S, Petiot A, Sadoul R. ALG-2 interacting protein-X (Alix) is essential for clathrin-independent endocytosis and signaling. Sci Rep 2016; 6:26986. [PMID: 27244115 PMCID: PMC4886688 DOI: 10.1038/srep26986] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 05/09/2016] [Indexed: 12/22/2022] Open
Abstract
The molecular mechanisms and the biological functions of clathrin independent endocytosis (CIE) remain largely elusive. Alix (ALG-2 interacting protein X), has been assigned roles in membrane deformation and fission both in endosomes and at the plasma membrane. Using Alix ko cells, we show for the first time that Alix regulates fluid phase endocytosis and internalization of cargoes entering cells via CIE, but has no apparent effect on clathrin mediated endocytosis or downstream endosomal trafficking. We show that Alix acts with endophilin-A to promote CIE of cholera toxin and to regulate cell migration. We also found that Alix is required for fast endocytosis and downstream signaling of the interleukin-2 receptor giving a first indication that CIE is necessary for activation of at least some surface receptors. In addition to characterizing a new function for Alix, our results highlight Alix ko cells as a unique tool to unravel the biological consequences of CIE.
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Affiliation(s)
- Vincent Mercier
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unité 1216, F-38042 Grenoble, France.,Université Grenoble Alpes, Institut des Neurosciences, F-38042 Grenoble, France
| | - Marine H Laporte
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unité 1216, F-38042 Grenoble, France.,Université Grenoble Alpes, Institut des Neurosciences, F-38042 Grenoble, France
| | - Olivier Destaing
- INSERM U1209, Grenoble, F-38042, France.,Université Grenoble Alpes, Institut Albert Bonniot, F-38000 Grenoble, France.,CNRS UMR 5309, F-38000 Grenoble, France
| | - Béatrice Blot
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unité 1216, F-38042 Grenoble, France.,Université Grenoble Alpes, Institut des Neurosciences, F-38042 Grenoble, France
| | - Cédric M Blouin
- Institut Curie, PSL Research University, Membrane Dynamics and Mechanics of Intracellular Signaling Laboratory, Paris, France.,INSERM, U1143, Paris, France.,CNRS, UMR 3666, Paris, France
| | - Karin Pernet-Gallay
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unité 1216, F-38042 Grenoble, France.,Université Grenoble Alpes, Institut des Neurosciences, F-38042 Grenoble, France
| | - Christine Chatellard
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unité 1216, F-38042 Grenoble, France.,Université Grenoble Alpes, Institut des Neurosciences, F-38042 Grenoble, France
| | - Yasmina Saoudi
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unité 1216, F-38042 Grenoble, France.,Université Grenoble Alpes, Institut des Neurosciences, F-38042 Grenoble, France
| | - Corinne Albiges-Rizo
- INSERM U1209, Grenoble, F-38042, France.,Université Grenoble Alpes, Institut Albert Bonniot, F-38000 Grenoble, France.,CNRS UMR 5309, F-38000 Grenoble, France
| | - Christophe Lamaze
- Institut Curie, PSL Research University, Membrane Dynamics and Mechanics of Intracellular Signaling Laboratory, Paris, France.,INSERM, U1143, Paris, France.,CNRS, UMR 3666, Paris, France
| | - Sandrine Fraboulet
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unité 1216, F-38042 Grenoble, France.,Université Grenoble Alpes, Institut des Neurosciences, F-38042 Grenoble, France
| | - Anne Petiot
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unité 1216, F-38042 Grenoble, France.,Université Grenoble Alpes, Institut des Neurosciences, F-38042 Grenoble, France
| | - Rémy Sadoul
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unité 1216, F-38042 Grenoble, France.,Université Grenoble Alpes, Institut des Neurosciences, F-38042 Grenoble, France
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18
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Saslowsky DE, Thiagarajah JR, McCormick BA, Lee JC, Lencer WI. Microbial sphingomyelinase induces RhoA-mediated reorganization of the apical brush border membrane and is protective against invasion. Mol Biol Cell 2016; 27:1120-30. [PMID: 26864627 PMCID: PMC4814219 DOI: 10.1091/mbc.e15-05-0293] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 02/01/2016] [Indexed: 12/19/2022] Open
Abstract
Both commensal and pathogenic microbes that colonize the GI tract can synthesize and secrete spingomyelinase enzymes that cleave membrane sphingomyelin, leaving the ceramide component intact in the cell membrane. This study examines how this reaction affects the structure and function of host enterocytes and mucosal defense. The apical brush border membrane (BBM) of intestinal epithelial cells forms a highly structured and dynamic environmental interface that serves to regulate cellular physiology and block invasion by intestinal microbes and their products. How the BBM dynamically responds to pathogenic and commensal bacterial signals can define intestinal homeostasis and immune function. We previously found that in model intestinal epithelium, the conversion of apical membrane sphingomyelin to ceramide by exogenous bacterial sphingomyelinase (SMase) protected against the endocytosis and toxicity of cholera toxin. Here we elucidate a mechanism of action by showing that SMase induces a dramatic, reversible, RhoA-dependent alteration of the apical cortical F-actin network. Accumulation of apical membrane ceramide is necessary and sufficient to induce the actin phenotype, and this coincides with altered membrane structure and augmented innate immune function as evidenced by resistance to invasion by Salmonella.
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Affiliation(s)
- David E Saslowsky
- Division of Gastroenterology and Nutrition, Boston Children's Hospital, Boston, MA 02115 Harvard Digestive Diseases Center, Boston Children's Hospital, Boston, MA 02115 Harvard Medical School, Boston, MA 02115
| | - Jay R Thiagarajah
- Division of Gastroenterology and Nutrition, Boston Children's Hospital, Boston, MA 02115 Harvard Digestive Diseases Center, Boston Children's Hospital, Boston, MA 02115 Harvard Medical School, Boston, MA 02115
| | - Beth A McCormick
- Harvard Digestive Diseases Center, Boston Children's Hospital, Boston, MA 02115 Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01655
| | - Jean C Lee
- Harvard Medical School, Boston, MA 02115 Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115
| | - Wayne I Lencer
- Division of Gastroenterology and Nutrition, Boston Children's Hospital, Boston, MA 02115 Harvard Digestive Diseases Center, Boston Children's Hospital, Boston, MA 02115 Harvard Medical School, Boston, MA 02115
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19
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Basu I, Mukhopadhyay C. Insights into binding of cholera toxin to GM1 containing membrane. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:15244-15252. [PMID: 25425333 DOI: 10.1021/la5036618] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Interactions of cholera toxin (CT) with membrane are associated with the massive secretory diarrhea seen in Asiatic cholera. Ganglioside GM1 has been shown to be responsible for the binding of the B subunit of cholera toxin (CT-B), which then helps CT to pass through the membrane, but the exact mechanism remains to be explored. In this work, we have carried out atomistic scale molecular dynamics simulation to investigate the structural changes of CT upon membrane binding and alteration in membrane structure and dynamics. Starting from the initial structure where the five units of B subunit bind with five GM1, only three of five units remain bound and the whole CT is tilted such that the three binding units are deeper in the membrane. The lipids that are in contact with those units of the CT-B behave differently from the rest of the lipids. Altogether, our results demonstrate the atomistic interaction of CT with GM1 containing lipid membrane and provide a probable mechanism of the early stage alteration of lipid structure and dynamics, which can make a passage for penetration of CT on membrane surface.
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Affiliation(s)
- Ipsita Basu
- Department of Chemistry, University of Calcutta , 92, A. P. C. Road, Kolkata - 700009, India
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20
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Garrigues HJ, DeMaster LK, Rubinchikova YE, Rose TM. KSHV attachment and entry are dependent on αVβ3 integrin localized to specific cell surface microdomains and do not correlate with the presence of heparan sulfate. Virology 2014; 464-465:118-133. [PMID: 25063885 DOI: 10.1016/j.virol.2014.06.035] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 03/02/2014] [Accepted: 06/27/2014] [Indexed: 11/16/2022]
Abstract
Cellular receptors for KSHV attachment and entry were characterized using tyramide signal amplification (TSA)-enhanced confocal microscopy. Integrins αVβ3, αVβ5 and α3β1 were detected on essentially all the actin-based cell surface microdomains that initially bind KSHV, while the presence of CD98 and heparan sulfate (HS), the putative attachment receptor, was more variable. KSHV bound to the same cell surface microdomains with and without HS indicating that initial attachment of KSHV is not dependent on HS and that receptors other than HS can mediate attachment. A human salivary gland (HSG) epithelial line was identified, which lacks αVβ3 but expresses high levels of HS, α3β1 and other putative KSHV receptors. These cells were resistant to KSHV binding and infection. Reconstitution of cell surface αVβ3 rendered HSG cells highly susceptible to KSHV infection, demonstrating a critical role for αVβ3 in the binding and entry of KSHV that is not shared with other proposed receptors.
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Affiliation(s)
- H Jacques Garrigues
- Seattle Children׳s Research Institute, 1900 Ninth Avenue, 8th Floor, Seattle, WA 98101, USA.
| | - Laura K DeMaster
- Seattle Children׳s Research Institute, 1900 Ninth Avenue, 8th Floor, Seattle, WA 98101, USA; Department of Global Health, University of Washington, Seattle, WA 98195, USA.
| | - Yelena E Rubinchikova
- Seattle Children׳s Research Institute, 1900 Ninth Avenue, 8th Floor, Seattle, WA 98101, USA.
| | - Timothy M Rose
- Seattle Children׳s Research Institute, 1900 Ninth Avenue, 8th Floor, Seattle, WA 98101, USA; Department of Pediatrics, University of Washington, Seattle, WA 98195, USA.
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21
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Pathogenesis of human enterovirulent bacteria: lessons from cultured, fully differentiated human colon cancer cell lines. Microbiol Mol Biol Rev 2014; 77:380-439. [PMID: 24006470 DOI: 10.1128/mmbr.00064-12] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Hosts are protected from attack by potentially harmful enteric microorganisms, viruses, and parasites by the polarized fully differentiated epithelial cells that make up the epithelium, providing a physical and functional barrier. Enterovirulent bacteria interact with the epithelial polarized cells lining the intestinal barrier, and some invade the cells. A better understanding of the cross talk between enterovirulent bacteria and the polarized intestinal cells has resulted in the identification of essential enterovirulent bacterial structures and virulence gene products playing pivotal roles in pathogenesis. Cultured animal cell lines and cultured human nonintestinal, undifferentiated epithelial cells have been extensively used for understanding the mechanisms by which some human enterovirulent bacteria induce intestinal disorders. Human colon carcinoma cell lines which are able to express in culture the functional and structural characteristics of mature enterocytes and goblet cells have been established, mimicking structurally and functionally an intestinal epithelial barrier. Moreover, Caco-2-derived M-like cells have been established, mimicking the bacterial capture property of M cells of Peyer's patches. This review intends to analyze the cellular and molecular mechanisms of pathogenesis of human enterovirulent bacteria observed in infected cultured human colon carcinoma enterocyte-like HT-29 subpopulations, enterocyte-like Caco-2 and clone cells, the colonic T84 cell line, HT-29 mucus-secreting cell subpopulations, and Caco-2-derived M-like cells, including cell association, cell entry, intracellular lifestyle, structural lesions at the brush border, functional lesions in enterocytes and goblet cells, functional and structural lesions at the junctional domain, and host cellular defense responses.
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22
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Establishment of an in vitro transport assay that reveals mechanistic differences in cytosolic events controlling cholera toxin and T-cell receptor α retro-translocation. PLoS One 2013; 8:e75801. [PMID: 24146777 PMCID: PMC3795749 DOI: 10.1371/journal.pone.0075801] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 08/21/2013] [Indexed: 11/19/2022] Open
Abstract
Following retrograde trafficking to the endoplasmic reticulum (ER), cholera toxin A1 (CTA1) subunit hijacks ER-associated degradation (ERAD) machinery and retro-translocates into the cytosol to induce toxicity. We previously established a cell-based in vivo assay to identify ER components that regulate this process. However, elucidating cytosolic events that govern CTA1 retro-translocation using this assay is difficult as manipulating cytosolic factors often perturbs toxin retrograde transport to the ER. To circumvent this problem, we developed an in vitro assay in semi-permeabilized cells that directly monitors CTA1 release from the ER into the cytosol. We demonstrate CTA1 is released into the cytosol as a folded molecule in a p97- and proteasome-independent manner. Release nonetheless involves a GTP-dependent reaction. Upon extending this assay to the canonical ERAD substrate T-cell receptor α (TCRα), we found the receptor is unfolded when released into the cytosol and degraded by membrane-associated proteasome. In this reaction, p97 initially extracts TCRα from the ER membrane, followed by TCRα discharge into the cytosol that requires additional energy-dependent cytosolic activities. Our results reveal mechanistic insights into cytosolic events controlling CTA1 and TCRα retro-translocation, and provide a reliable tool to further probe this process.
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23
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Reddy S, Taylor M, Zhao M, Cherubin P, Geden S, Ray S, Francis D, Teter K. Grape extracts inhibit multiple events in the cell biology of cholera intoxication. PLoS One 2013; 8:e73390. [PMID: 24039929 PMCID: PMC3764128 DOI: 10.1371/journal.pone.0073390] [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: 09/28/2012] [Accepted: 07/01/2013] [Indexed: 01/07/2023] Open
Abstract
Vibrio cholerae produces cholera toxin (CT), an AB5 protein toxin that is primarily responsible for the profuse watery diarrhea of cholera. CT is secreted into the extracellular milieu, but the toxin attacks its Gsα target within the cytosol of a host cell. Thus, CT must cross a cellular membrane barrier in order to function. This event only occurs after the toxin travels by retrograde vesicular transport from the cell surface to the endoplasmic reticulum (ER). The catalytic A1 polypeptide then dissociates from the rest of the toxin and assumes an unfolded conformation that facilitates its transfer to the cytosol by a process involving the quality control system of ER-associated degradation. Productive intoxication is blocked by alterations to the vesicular transport of CT and/or the ER-to-cytosol translocation of CTA1. Various plant compounds have been reported to inhibit the cytopathic activity of CT, so in this work we evaluated the potential anti-CT properties of grape extract. Two grape extracts currently sold as nutritional supplements inhibited CT and Escherichia coli heat-labile toxin activity against cultured cells and intestinal loops. CT intoxication was blocked even when the extracts were added an hour after the initial toxin exposure. A specific subset of host-toxin interactions involving both the catalytic CTA1 subunit and the cell-binding CTB pentamer were affected. The extracts blocked toxin binding to the cell surface, prevented unfolding of the isolated CTA1 subunit, inhibited CTA1 translocation to the cytosol, and disrupted the catalytic activity of CTA1. Grape extract could thus potentially serve as a novel therapeutic to prevent or possibly treat cholera.
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Affiliation(s)
- Srikar Reddy
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, United States of America
- Lake Highland Preparatory School, Orlando, Florida, United States of America
| | - Michael Taylor
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, United States of America
| | - Mojun Zhao
- The Center for Infectious Disease Research and Vaccinology, Department of Veterinary and Biomedical Sciences, South Dakota State University, Brookings, South Dakota, United States of America
| | - Patrick Cherubin
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, United States of America
| | - Sandra Geden
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, United States of America
| | - Supriyo Ray
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, United States of America
| | - David Francis
- The Center for Infectious Disease Research and Vaccinology, Department of Veterinary and Biomedical Sciences, South Dakota State University, Brookings, South Dakota, United States of America
| | - Ken Teter
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, United States of America
- * E-mail:
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24
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Lai CH, Lai CK, Lin YJ, Hung CL, Chu CH, Feng CL, Chang CS, Su HL. Characterization of putative cholesterol recognition/interaction amino acid consensus-like motif of Campylobacter jejuni cytolethal distending toxin C. PLoS One 2013; 8:e66202. [PMID: 23762481 PMCID: PMC3675143 DOI: 10.1371/journal.pone.0066202] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 05/02/2013] [Indexed: 12/17/2022] Open
Abstract
Cytolethal distending toxin (CDT) produced by Campylobacter jejuni comprises a heterotrimeric complex formed by CdtA, CdtB, and CdtC. Among these toxin subunits, CdtA and CdtC function as essential proteins that mediate toxin binding to cytoplasmic membranes followed by delivery of CdtB into the nucleus. The binding of CdtA/CdtC to the cell surface is mediated by cholesterol, a major component in lipid rafts. Although the putative cholesterol recognition/interaction amino acid consensus (CRAC) domain of CDT has been reported from several bacterial pathogens, the protein regions contributing to CDT binding to cholesterol in C. jejuni remain unclear. Here, we selected a potential CRAC-like region present in the CdtC from C. jejuni for analysis. Molecular modeling showed that the predicted functional domain had the shape of a hydrophobic groove, facilitating cholesterol localization to this domain. Mutation of a tyrosine residue in the CRAC-like region decreased direct binding of CdtC to cholesterol rather than toxin intermolecular interactions and led to impaired CDT intoxication. These results provide a molecular link between C. jejuni CdtC and membrane-lipid rafts through the CRAC-like region, which contributes to toxin recognition and interaction with cholesterol.
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Affiliation(s)
- Chih-Ho Lai
- Department of Microbiology, School of Medicine, Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan
- * E-mail: (CHL); (HLS)
| | - Cheng-Kuo Lai
- Department of Microbiology, School of Medicine, Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan
- Department of Life Sciences, Agricultural Biotechnology Center, National Chung Hsing University, Taichung, Taiwan
| | - Ying-Ju Lin
- School of Chinese Medicine, China Medical University, Taichung, Taiwan
| | - Chiu-Lien Hung
- Department of Biochemistry and Molecular Medicine, University of California Davis Comprehensive Cancer Center, Sacramento, California, United States of America
| | - Chia-Han Chu
- Biomedical Science and Engineering Center, National Tsing Hua University, Hsinchu, Taiwan
| | - Chun-Lung Feng
- Department of Internal Medicine, China Medical University Hospital, Taichung, Taiwan
| | - Chia-Shuo Chang
- Department of Microbiology, School of Medicine, Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan
| | - Hong-Lin Su
- Department of Life Sciences, Agricultural Biotechnology Center, National Chung Hsing University, Taichung, Taiwan
- Department of Physical Therapy, China Medical University, Taichung, Taiwan
- * E-mail: (CHL); (HLS)
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Lai CH, Hsu YM, Wang HJ, Wang WC. Manipulation of host cholesterol by Helicobacter pylori for their beneficial ecological niche. Biomedicine (Taipei) 2013. [DOI: 10.1016/j.biomed.2012.12.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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Jobling MG, Yang Z, Kam WR, Lencer WI, Holmes RK. A single native ganglioside GM1-binding site is sufficient for cholera toxin to bind to cells and complete the intoxication pathway. mBio 2012; 3:e00401-12. [PMID: 23111873 PMCID: PMC3487775 DOI: 10.1128/mbio.00401-12] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Accepted: 10/05/2012] [Indexed: 01/02/2023] Open
Abstract
Cholera toxin (CT) from Vibrio cholerae is responsible for the majority of the symptoms of the diarrheal disease cholera. CT is a heterohexameric protein complex with a 240-residue A subunit and a pentameric B subunit of identical 103-residue B polypeptides. The A subunit is proteolytically cleaved within a disulfide-linked loop to generate the A1 and A2 fragments. The B subunit of wild-type (wt) CT binds 5 cell surface ganglioside GM(1) (GM(1)) molecules, and the toxin-GM(1) complex traffics from the plasma membrane (PM) retrograde through endosomes and the Golgi apparatus to the endoplasmic reticulum (ER). From the ER, the enzymatic A1 fragment retrotranslocates to the cytosol to cause disease. Clustering of GM(1) by multivalent toxin binding can structurally remodel cell membranes in ways that may assist toxin uptake and retrograde trafficking. We have recently found, however, that CT may traffic from the PM to the ER by exploiting an endogenous glycosphingolipid pathway (A. A. Wolf et al., Infect. Immun. 76:1476-1484, 2008, and D. J. F. Chinnapen et al., Dev. Cell 23:573-586, 2012), suggesting that multivalent binding to GM(1) is dispensable. Here we formally tested this idea by creating homogenous chimeric holotoxins with defined numbers of native GM(1) binding sites from zero (nonbinding) to five (wild type). We found that a single GM(1) binding site is sufficient for activity of the holotoxin. Therefore, remodeling of cell membranes by mechanisms that involve multivalent binding of toxin to GM(1) receptors is not essential for toxicity of CT. Through multivalent binding to its lipid receptor, cholera toxin (CT) can remodel cell membranes in ways that may assist host cell invasion. We recently found that CT variants which bind no more than 2 receptor molecules do exhibit toxicity, suggesting that CT may be able to enter cells by coopting an endogenous lipid sorting pathway without clustering receptors. We tested this idea directly by using purified variants of CT with zero to five functional receptor-binding sites (BS). One BS enabled CT to intoxicate cells, supporting the conclusion that CT can enter cells by coopting an endogenous lipid-sorting pathway. Although multivalent receptor binding is not essential, it does increase CT toxicity. These findings suggest that achieving higher receptor binding avidity or affecting membrane dynamics by lipid clustering and membrane remodeling may be driving forces for evolution of AB(5) subunit toxins that can bind multivalently to cell membrane lipid receptors.
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Affiliation(s)
- Michael G. Jobling
- Department of Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - ZhiJie Yang
- Department of Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Wendy R. Kam
- GI Cell Biology, Department of Pediatrics, Children’s Hospital, Boston, Massachusetts, USA; and
| | | | - Randall K. Holmes
- Department of Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
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Ray S, Taylor M, Banerjee T, Tatulian SA, Teter K. Lipid rafts alter the stability and activity of the cholera toxin A1 subunit. J Biol Chem 2012; 287:30395-405. [PMID: 22787142 DOI: 10.1074/jbc.m112.385575] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cholera toxin (CT) travels from the cell surface to the endoplasmic reticulum (ER) as an AB holotoxin. ER-specific conditions then promote the dissociation of the catalytic CTA1 subunit from the rest of the toxin. CTA1 is held in a stable conformation by its assembly in the CT holotoxin, but the dissociated CTA1 subunit is an unstable protein that spontaneously assumes a disordered state at physiological temperature. This unfolding event triggers the ER-to-cytosol translocation of CTA1 through the quality control mechanism of ER-associated degradation. The translocated pool of CTA1 must regain a folded, active structure to modify its G protein target which is located in lipid rafts at the cytoplasmic face of the plasma membrane. Here, we report that lipid rafts place disordered CTA1 in a functional conformation. The hydrophobic C-terminal domain of CTA1 is essential for binding to the plasma membrane and lipid rafts. These interactions inhibit the temperature-induced unfolding of CTA1. Moreover, lipid rafts could promote a gain of structure in the disordered, 37 °C conformation of CTA1. This gain of structure corresponded to a gain of function: whereas CTA1 by itself exhibited minimal in vitro activity at 37 °C, exposure to lipid rafts resulted in substantial toxin activity at 37 °C. In vivo, the disruption of lipid rafts with filipin substantially reduced the activity of cytosolic CTA1. Lipid rafts thus exhibit a chaperone-like function that returns disordered CTA1 to an active state and is required for the optimal in vivo activity of CTA1.
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Affiliation(s)
- Supriyo Ray
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32826, USA
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Johnson BB, Moe PC, Wang D, Rossi K, Trigatti BL, Heuck AP. Modifications in Perfringolysin O Domain 4 Alter the Cholesterol Concentration Threshold Required for Binding. Biochemistry 2012; 51:3373-82. [DOI: 10.1021/bi3003132] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
| | | | - David Wang
- Department of Biochemistry and
Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | - Kathleen Rossi
- Department of Biochemistry and
Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | - Bernardo L. Trigatti
- Department of Biochemistry and
Biomedical Sciences, McMaster University, Hamilton, ON, Canada
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Dietary ganglioside reduces proinflammatory signaling in the intestine. J Nutr Metab 2012; 2012:280286. [PMID: 22506104 PMCID: PMC3306953 DOI: 10.1155/2012/280286] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Revised: 10/07/2011] [Accepted: 10/07/2011] [Indexed: 12/31/2022] Open
Abstract
Gangliosides are integral to the structure and function of cell membranes. Ganglioside composition of the intestinal brush border and apical surface of the colon influences numerous cell processes including microbial attachment, cell division, differentiation, and signaling. Accelerated catabolism of ganglioside in intestinal disease results in increased proinflammatory signaling. Restoring proper structure and function to the diseased intestine can resolve inflammation, increase resistance to infection, and improve gut integrity to induce remission of conditions like necrotizing enterocolitis (NEC) and Crohn's disease (CD). Maintaining inactive state of disease may be achieved by reducing the rate that gangliosides are degraded or by increasing intake of dietary ganglioside. Collectively, the studies outlined in this paper indicate that the amount of gangliosides GM3 and GD3 in intestinal mucosa is decreased with inflammation, low level of GM3 is associated with higher production of proinflammatory signals, and ganglioside content of intestinal mucosa can be increased by dietary ganglioside.
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Abstract
Receptor-mediated endocytosis is used by a number of viruses and toxins to gain entry into cells. Some have evolved to use specific lipids in the plasma membrane as their receptors. They include bacterial toxins such as Shiga and Cholera toxin and viruses such as mouse polyoma virus and simian virus 40. Through multivalent binding to glycosphingolipids, they induce lipid clustering and changes in membrane properties. Internalization occurs by unusual endocytic mechanisms involving lipid rafts, induction of membrane curvature, trans-bilayer coupling, and activation of signaling pathways. Once delivered to early endosomes, they follow diverse intracellular routes to the lumen of the ER, from which they penetrate into the cytosol. The role of the lipid receptors is central in these well-studied processes.
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Affiliation(s)
- Helge Ewers
- Laboratorium für Physikalische Chemie, ETH Zurich, 8093 Zurich, Switzerland
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31
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Lin AEJ, Guttman JA. Hijacking the endocytic machinery by microbial pathogens. PROTOPLASMA 2010; 244:75-90. [PMID: 20574860 DOI: 10.1007/s00709-010-0164-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Accepted: 05/19/2010] [Indexed: 05/24/2023]
Abstract
Understanding the mechanisms that microbes exploit to invade host cells and cause disease is crucial if we are to eliminate their threat. Although pathogens use a variety of microbial factors to trigger entry into non-phagocytic cells, their targeting of the host cell process of endocytosis has emerged as a common theme. To accomplish this, microbes often rewire the normal course of particle internalization, frequently usurping theoretical maximal sizes to permit entry and reconfiguring molecular components that were once thought to be required for vesicle formation. Here, we discuss recent advances in our understanding of how toxins, viruses, bacteria, and fungi manipulate the host cell endocytic machinery to generate diseases. Additionally, we will reveal the advantages of using these organisms to expand our general knowledge of endocytic mechanisms in eukaryotic cells.
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Affiliation(s)
- Ann En-Ju Lin
- Department of Biological Sciences, Shrum Science Centre, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada
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32
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Wernick NLB, Chinnapen DJF, Cho JA, Lencer WI. Cholera toxin: an intracellular journey into the cytosol by way of the endoplasmic reticulum. Toxins (Basel) 2010; 2:310-25. [PMID: 22069586 PMCID: PMC3153193 DOI: 10.3390/toxins2030310] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Revised: 02/27/2010] [Accepted: 03/02/2010] [Indexed: 01/09/2023] Open
Abstract
Cholera toxin (CT), an AB(5)-subunit toxin, enters host cells by binding the ganglioside GM1 at the plasma membrane (PM) and travels retrograde through the trans-Golgi Network into the endoplasmic reticulum (ER). In the ER, a portion of CT, the enzymatic A1-chain, is unfolded by protein disulfide isomerase and retro-translocated to the cytosol by hijacking components of the ER associated degradation pathway for misfolded proteins. After crossing the ER membrane, the A1-chain refolds in the cytosol and escapes rapid degradation by the proteasome to induce disease by ADP-ribosylating the large G-protein Gs and activating adenylyl cyclase. Here, we review the mechanisms of toxin trafficking by GM1 and retro-translocation of the A1-chain to the cytosol.
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Affiliation(s)
- Naomi L. B. Wernick
- GI Cell Biology, Children's Hospital (and Harvard Medical School), 300 Longwood Avenues, Enders 720, Boston, MA 02115, USA; (N.L.B.W.); (D.J.-F.C.); (J.A.C.)
| | - Daniel J.-F. Chinnapen
- GI Cell Biology, Children's Hospital (and Harvard Medical School), 300 Longwood Avenues, Enders 720, Boston, MA 02115, USA; (N.L.B.W.); (D.J.-F.C.); (J.A.C.)
| | - Jin Ah Cho
- GI Cell Biology, Children's Hospital (and Harvard Medical School), 300 Longwood Avenues, Enders 720, Boston, MA 02115, USA; (N.L.B.W.); (D.J.-F.C.); (J.A.C.)
| | - Wayne I. Lencer
- GI Cell Biology, Children's Hospital (and Harvard Medical School), 300 Longwood Avenues, Enders 720, Boston, MA 02115, USA; (N.L.B.W.); (D.J.-F.C.); (J.A.C.)
- The Harvard Digestive Diseases Center, Boston, MA 02115, USA
- Author to whom correspondence should be addressed; ; Tel.: +617-919-2573; Fax: +617-730-0498
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Protection of intestinal occludin tight junction protein by dietary gangliosides in lipopolysaccharide-induced acute inflammation. J Pediatr Gastroenterol Nutr 2010; 50:321-8. [PMID: 20118807 DOI: 10.1097/mpg.0b013e3181ae2ba0] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
OBJECTIVES Intestinal permeability and barrier function are regulated by expression of tight junction proteins. Lipopolysaccharide (LPS), tumor necrosis factor-alpha, and interleukin-1beta induce expression of nitric oxide (NO) and reduce the expression of gut tight junction proteins. The purpose of this study was to determine whether dietary gangliosides (GGs) increase the concentration of the anti-inflammatory cytokine interleukin-10 (IL-10) in response to LPS, thereby inhibiting NO production and protecting gut occludin tight junction protein from degradation. MATERIALS AND METHODS Rats were fed semipurified diets with (n = 16) or without (n = 16) GGs (0.1% w/w of total lipid). After 2 weeks of feeding, animals were injected with saline (n = 8/diet group) or LPS (n = 8/diet group) (IP, 3 mg mL(-1) kg(-1)). Intestinal tissue, mucosa, and blood sample were collected 6 hours post-LPS exposure. The effect of dietary GGs on production/expression of IL-10, NO, inducible NO synthase, and occludin protein was determined. RESULTS Dietary GGs increased IL-10 content in intestinal mucosa significantly by 32-fold (P < 0.0001) and in plasma by 2.4-fold (P < 0.001). Feeding animals a ganglioside-enriched diet decreased total NO content in intestinal mucosa and plasma by 44% and 30%, respectively, and inhibited inducible NO synthase expression following LPS exposure compared with control animals. Dietary GGs reduced the degradation of occludin tight junction protein in response to LPS. CONCLUSIONS Dietary GGs inhibit degradation of gut occludin tight junction protein during LPS-induced acute inflammation. Thus, dietary GGs have a role in protecting the integrity of the intestinal barrier during acute gut inflammation.
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Bridge DR, Novotny MJ, Moore ER, Olson JC. Role of host cell polarity and leading edge properties in Pseudomonas type III secretion. MICROBIOLOGY-SGM 2009; 156:356-373. [PMID: 19910414 DOI: 10.1099/mic.0.033241-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Type III secretion (T3S) functions in establishing infections in a large number of Gram-negative bacteria, yet little is known about how host cell properties might function in this process. We used the opportunistic pathogen Pseudomonas aeruginosa and the ability to alter host cell sensitivity to Pseudomonas T3S to explore this problem. HT-29 epithelial cells were used to study cellular changes associated with loss of T3S sensitivity, which could be induced by treatment with methyl-beta-cyclodextrin or perfringolysin O. HL-60 promyelocytic cells are innately resistant to Pseudomonas T3S and were used to study cellular changes occurring in response to induction of T3S sensitivity, which occurred following treatment with phorbol esters. Using both cell models, a positive correlation was observed between eukaryotic cell adherence to tissue culture wells and T3S sensitivity. In examining the type of adhesion process linked to T3S sensitivity in HT-29 cells, a hierarchical order of protein involvement was identified that paralleled the architecture of leading edge (LE) focal complexes. Conversely, in HL-60 cells, induction of T3S sensitivity coincided with the onset of LE properties and the development of actin-rich projections associated with polarized cell migration. When LE architecture was examined by immunofluorescent staining for actin, Rac1, IQ-motif-containing GTPase-activating protein 1 (IQGAP1) and phosphatidylinositol 3 kinase (PI3 kinase), intact LE structure was found to closely correlate with host cell sensitivity to P. aeruginosa T3S. Our model for host cell involvement in Pseudomonas T3S proposes that cortical actin polymerization at the LE alters membrane properties to favour T3S translocon function and the establishment of infections, which is consistent with Pseudomonas infections targeting wounded epithelial barriers undergoing cell migration.
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Affiliation(s)
- Dacie R Bridge
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University Health Sciences Center, Morgantown, WV 26506-9177, USA
| | - Matthew J Novotny
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University Health Sciences Center, Morgantown, WV 26506-9177, USA
| | - Elizabeth R Moore
- Laboratory of Intracellular Parasites, NIAID, Rocky Mountain Laboratories, Hamilton, MT 59840, USA
| | - Joan C Olson
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University Health Sciences Center, Morgantown, WV 26506-9177, USA
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Hickey DK, Aldwell FE, Beagley KW. Transcutaneous immunization with a novel lipid-based adjuvant protects against Chlamydia genital and respiratory infections. Vaccine 2009; 27:6217-25. [PMID: 19698810 DOI: 10.1016/j.vaccine.2009.08.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2008] [Revised: 07/29/2009] [Accepted: 08/02/2009] [Indexed: 12/30/2022]
Abstract
Mucosal adjuvants are important to overcome the state of immune tolerance normally associated with mucosal delivery and to enhance adaptive immunity to often-weakly immunogenic subunit vaccine antigens. Unfortunately, adverse side effects of many experimental adjuvants limit the number of adjuvants approved for vaccination. Lipid C is a novel, non-toxic, lipid oral vaccine-delivery formulation, developed originally for oral delivery of the live Mycobacterium bovis Bacille Calmette-Guerin (BCG) vaccine. In the present study, murine models of chlamydial respiratory and genital tract infections were used to determine whether transcutaneous immunization (TCI) with Lipid C-incorporated protein antigens could elicit protective immunity at the genital and respiratory mucosae. BALB/c mice were immunized transcutaneously with Lipid C containing the chlamydial major outer membrane protein (MOMP), with and without addition of cholera toxin and CpG-ODN 1826 (CT/CpG). Both vaccine combinations induced mixed cell-mediated and mucosal antibody immune responses. Immunization with Lipid C-incorporated MOMP (Lipid C/MOMP), either alone or with CT/CpG resulted in partial protection following live challenge with Chlamydia muridarum as evidenced by a significant reduction in recoverable Chlamydia from both the genital secretions and lung tissue. Protection induced by immunization with Lipid C/MOMP alone was not further enhanced by the addition of CT/CpG. These results highlight the potential of Lipid C as a novel mucosal adjuvant capable of targeting multiple mucosal surfaces following TCI. Protection at both the respiratory and genital mucosae was achieved without the requirement for potentially toxic adjuvants, suggesting that Lipid C may provide a safe effective mucosal adjuvant for human vaccination.
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Affiliation(s)
- Danica K Hickey
- School of Biomedical Sciences, The University of Newcastle, Newcastle, Australia and Hunter Medical Research Institute, Newcastle, Australia
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36
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De Haan L, Hirst TR. Cholera toxin: A paradigm for multi-functional engagement of cellular mechanisms (Review). Mol Membr Biol 2009; 21:77-92. [PMID: 15204437 DOI: 10.1080/09687680410001663267] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Cholera toxin (Ctx) from Vibrio cholerae and its closely related homologue, heat-labile enterotoxin (Etx) from Escherichia coli have become superb tools for illuminating pathways of cellular trafficking and immune cell function. These bacterial protein toxins should be viewed as conglomerates of highly evolved, multi-functional elements equipped to engage the trafficking and signalling machineries of cells. Ctx and Etx are members of a larger family of A-B toxins of bacterial (and plant) origin that are comprised of structurally and functionally distinct enzymatically active A and receptor-binding B sub-units or domains. Intoxication of mammalian cells by Ctx and Etx involves B pentamer-mediated receptor binding and entry into a vesicular pathway, followed by translocation of the enzymatic A1 domain of the A sub-unit into the target cell cytosol, where covalent modification of intracellular targets leads to activation of adenylate cyclase and a sequence of events culminating in life-threatening diarrhoeal disease. Importantly, Ctx and Etx also have the capacity to induce a wide spectrum of remarkable immunological processes. With respect to the latter, it has been found that these toxins activate signalling pathways that modulate the immune system. This review explores the complexities of the cellular interactions that are engaged by these bacterial protein toxins, and highlights some of the new insights to have recently emerged.
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Affiliation(s)
- Lolke De Haan
- Department of Pathology and Microbiology, School of Medical Sciences, University of Bristol, United Kingdom
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37
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Destainville N, Dumas F, Salomé L. What do diffusion measurements tell us about membrane compartmentalisation? Emergence of the role of interprotein interactions. J Chem Biol 2008; 1:37-48. [PMID: 19568797 PMCID: PMC2698319 DOI: 10.1007/s12154-008-0005-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2008] [Accepted: 03/11/2008] [Indexed: 01/28/2023] Open
Abstract
The techniques of diffusion analysis based on optical microscopy approaches have revealed a great diversity of the dynamic organisation of cell membranes. For a long period, two frameworks have dominated the way of representing the membrane structure: the membrane skeleton fences and the lipid raft models. Progresses in the methods of data analysis have shed light on the features and consequently the possible origin of membrane domains: Inter-protein interactions play a role in confinement. Innovative developments pushing forward the spatiotemporal resolution limits are currently emerging, which are likely to provide in the future a detailed understanding of the intimate functional dynamic organisation of the cell membrane.
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Affiliation(s)
- Nicolas Destainville
- Institut de Pharmacologie et Biologie Structurale, UMR 5089 CNRS, Université Paul Sabatier, 205 Route de Narbonne, 31062 Toulouse, France
- Laboratoire de Physique Théorique, IRSAMC, UMR 5152 CNRS, Université Paul Sabatier, 118 Route de Narbonne, 31062 Toulouse, France
| | - Fabrice Dumas
- Institut de Pharmacologie et Biologie Structurale, UMR 5089 CNRS, Université Paul Sabatier, 205 Route de Narbonne, 31062 Toulouse, France
- Cell Biophysics Laboratory, London Research Institute Lincoln’s Inn Fields Laboratories, 44 Lincoln’s Inn Fields, London, WC2 3PX UK
| | - Laurence Salomé
- Institut de Pharmacologie et Biologie Structurale, UMR 5089 CNRS, Université Paul Sabatier, 205 Route de Narbonne, 31062 Toulouse, France
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Fujinaga Y. HOW BACTERIAL TOXINS PENETRATE THE INTESTINAL EPITHELIAL BARRIER: STRATEGIES TAKEN BY CHOLERA TOXIN AND BOTULINUM PROGENITOR TOXIN. TOXIN REV 2008. [DOI: 10.1080/15569540500320904] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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39
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Edwards KA, Duan F, Baeumner AJ, March JC. Fluorescently labeled liposomes for monitoring cholera toxin binding to epithelial cells. Anal Biochem 2008; 380:59-67. [DOI: 10.1016/j.ab.2008.05.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2008] [Accepted: 05/18/2008] [Indexed: 11/16/2022]
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40
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Zwaagstra JC, Collins C, Langlois MJ, O'Connor-McCourt MD. Analysis of the contribution of receptor subdomains to the cooperative binding and internalization of transforming growth factor-β (TGF-β) type I and type II receptors. Exp Cell Res 2008; 314:2553-68. [DOI: 10.1016/j.yexcr.2008.06.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Revised: 06/03/2008] [Accepted: 06/04/2008] [Indexed: 10/22/2022]
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41
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Hanashima T, Miyake M, Yahiro K, Iwamaru Y, Ando A, Morinaga N, Noda M. Effect of Gb3 in lipid rafts in resistance to Shiga-like toxin of mutant Vero cells. Microb Pathog 2008; 45:124-33. [DOI: 10.1016/j.micpath.2008.04.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2007] [Revised: 04/07/2008] [Accepted: 04/18/2008] [Indexed: 11/26/2022]
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Attenuated endocytosis and toxicity of a mutant cholera toxin with decreased ability to cluster ganglioside GM1 molecules. Infect Immun 2008; 76:1476-84. [PMID: 18212085 DOI: 10.1128/iai.01286-07] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cholera toxin (CT) moves from the plasma membrane (PM) of host cells to the endoplasmic reticulum (ER) by binding to the lipid raft ganglioside GM(1). The homopentomeric B-subunit of the toxin can bind up to five GM(1) molecules at once. Here, we examined the role of polyvalent binding of GM(1) in CT action by producing chimeric CTs that had B-subunits with only one or two normal binding pockets for GM(1). The chimeric toxins had attenuated affinity for binding to host cell PM, as expected. Nevertheless, like wild-type (wt) CT, the CT chimeras induced toxicity, fractionated with detergent-resistant membranes extracted from toxin-treated cells, displayed restricted diffusion in the plane of the PM in intact cells, and remained bound to GM(1) when they were immunoprecipitated. Thus, binding normally to two or perhaps only one GM(1) molecule is sufficient for association with lipid rafts in the PM and toxin action. The chimeric toxins, however, were much less potent than wt toxin, and they entered the cell by endocytosis more slowly, suggesting that clustering of GM(1) molecules by the B-subunit enhances the efficiency of toxin uptake and perhaps also trafficking to the ER.
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43
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Saslowsky DE, Lencer WI. Conversion of apical plasma membrane sphingomyelin to ceramide attenuates the intoxication of host cells by cholera toxin. Cell Microbiol 2008; 10:67-80. [PMID: 18052945 DOI: 10.1111/j.1462-5822.2007.01015.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cholera toxin (CT) enters host cells by binding to ganglioside GM1 in the apical plasma membrane (PM). GM1 carries CT retrograde from the PM to the endoplasmic reticulum (ER), where a portion of the toxin, the A1-chain, retro-translocates to the cytosol, causing disease. Trafficking in this pathway appears to depend on the association of CT-GM1 complexes with sphingomyelin (SM)- and cholesterol-rich membrane microdomains termed lipid rafts. Here, we find that in polarized intestinal epithelia, the conversion of apical membrane SM to ceramide by bacterial sphingomyelinase attenuates CT toxicity, consistent with the lipid raft hypothesis. The effect is reversible, specific to toxin entry via the apical membrane, and recapitulated by the addition of exogenous long-chain ceramides. Conversion of apical membrane SM to ceramide inhibits the efficiency of toxin endocytosis, but retrograde trafficking from the apical PM to the Golgi and ER is not affected. This result suggests that the cause for toxin resistance occurs at steps required for retro-translocation of the CT A1-chain to the cytosol.
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Affiliation(s)
- David E Saslowsky
- Children's Hospital, Harvard Digestive Diseases Center, Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA.
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44
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Schnitzler AC, Burke JM, Wetzler LM. Induction of cell signaling events by the cholera toxin B subunit in antigen-presenting cells. Infect Immun 2007; 75:3150-9. [PMID: 17353279 PMCID: PMC1932910 DOI: 10.1128/iai.00581-06] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cholera toxin (CT) is one of the most effective and widely studied mucosal adjuvants. Although the ADP-ribosylating A subunit has been implicated in augmenting immune responses, the receptor-binding B subunit (CT-B) has greater immunogenicity and may be a repository of adjuvant activity without potential toxicity. In order to elucidate mechanisms of immune modulation by CT-B alone, primary B cells and macrophages were assessed for responses to CT-B in vitro, as measured by the expression of cell surface markers, cellular signaling events, and cytokine secretion. Increased phosphorylation of multiple signaling molecules, including Erk1/2 and p38, was detected. CT-B also induced transactivation of the transcription elements cyclic AMP-responsive element and NF-kappaB, the latter of which was inhibited by phosphotyrosine inhibition. While specific inhibition of MEK1/2 did not reduce CT-B induction of cell surface marker expression, it did attenuate CT-B-mediated interleukin-6 secretion. These data show that CT-B induces a set of signaling events related to cellular activation, surface molecule expression, and cytokine production that has potential implications for elucidating CT-B adjuvant activity in the absence of enzymatically active holotoxin.
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Affiliation(s)
- Aletta C Schnitzler
- Evans Biomedical Research Center, Boston University School of Medicine, 650 Albany Street, Boston, MA 02118, USA
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Grimmer S, Spilsberg B, Hanada K, Sandvig K. Depletion of sphingolipids facilitates endosome to Golgi transport of ricin. Traffic 2007; 7:1243-53. [PMID: 16919154 DOI: 10.1111/j.1600-0854.2006.00456.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
It has been previously demonstrated that depletion of cholesterol inhibits endosome to Golgi transport. Whether this inhibition is due to disruption of sphingolipid- and cholesterol-containing lipid rafts that are selected for Golgi transport or whether there is a physical requirement of cholesterol for either membrane deformations, facilitating formation of transport vesicles, or for recruitment of cytosolic constituents is not obvious. To investigate this in more detail, we have studied endosome to Golgi transport of ricin in sphingolipid-deficient cells using either a mutant cell line that does not express serine palmitoyltransferase, the first enzyme in sphingolipid biosynthesis, or a specific inhibitor, myriocin, of the same enzyme. Depletion of sphingolipids gave an increased sensitivity to ricin, and this increased sensitivity was inhibited by addition of sphingolipids. Importantly, endosome to Golgi transport of ricin, measured as sulfation of a modified ricin molecule, was increased in sphingolipid-deficient cells. No effect was seen on other pathways taken by ricin. Interestingly, cholesterol depletion inhibited endosome to Golgi transport even in cells with reduced levels of sphingolipids, suggesting that cholesterol as such is required for formation of transport vesicles. Our results indicate that the presence of sphingolipids actually limits and may function to control endosome to Golgi transport of ricin.
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Affiliation(s)
- Stine Grimmer
- Institute for Cancer Research, Department of Biochemistry, The Norwegian Radium Hospital, University of Oslo, Montebello, 0310 Oslo, Norway
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46
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Backer MV, Patel V, Jehning BT, Claffey KP, Karginov VA, Backer JM. Inhibition of anthrax protective antigen outside and inside the cell. Antimicrob Agents Chemother 2007; 51:245-51. [PMID: 17074791 PMCID: PMC1797656 DOI: 10.1128/aac.00983-06] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2006] [Revised: 08/26/2006] [Accepted: 10/16/2006] [Indexed: 11/20/2022] Open
Abstract
In the course of Bacillus anthracis infection, B. anthracis lethal factor (LF) and edema factor bind to a protective antigen (PA) associated with cellular receptors ANTXR1 (TEM8) or ANTXR2 (CMG2), followed by internalization of the complex via receptor-mediated endocytosis. A new group of potential antianthrax drugs, beta-cyclodextrins, has recently been described. A member of this group, per-6-(3-aminopropylthio)-beta-cyclodextrin (AmPrbetaCD), was shown to inhibit the toxicity of LF in vitro and in vivo. In order to determine which steps in lethal factor trafficking are inhibited by AmPrbetaCD, we developed two targeted fluorescent tracers based on LFn, a catalytically inactive fragment of LF: (i) LFn site specifically labeled with the fluorescent dye AlexaFluor-594 (LFn-Al), and (ii) LFn-decorated liposomes loaded with the fluorescent dye 8-hydroxypyrene-1,3,6-trisulfonic acid (LFn-Lip). Both tracers retained high affinity to PA/ANTXR complexes and were readily internalized via receptor-mediated endocytosis. Using fluorescent microscopy, we found that AmPrbetaCD inhibits receptor-mediated cell uptake but not the binding of LFn-Al to PA/ANTXR complexes, suggesting that AmPrbetaCD works outside the cell. Moreover, AmPrbetaCD and LFn-Al synergistically protect RAW 264.7 cells from PA-mediated LF toxicity, confirming that AmPrbetaCD did not affect the binding of LFn-Al to receptor-associated PA. In contrast, AmPrbetaCD did not inhibit PA-mediated internalization of LFn-Lip, suggesting that multiplexing of LFn on the liposomal surface overcomes the inhibiting effects of AmPrbetaCD. Notably, internalized LFn-Al and LFn-Lip protected cells that overexpressed anthrax receptor TEM8 from PA-induced, LF-independent toxicity, suggesting an independent mechanism for PA inhibition inside the cell. These data suggest the potential for the use of beta-cyclodextrins in combination with LFn-Lip loaded with antianthrax drugs against intracellular targets.
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Affiliation(s)
- Marina V Backer
- SibTech, Inc., 705 North Mountain Road, Newington, CT 06111, USA
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47
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Fujinaga Y. Transport of bacterial toxins into target cells: pathways followed by cholera toxin and botulinum progenitor toxin. J Biochem 2006; 140:155-60. [PMID: 16954533 DOI: 10.1093/jb/mvj161] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A number of bacterial toxins have sophisticated mechanisms for reaching their specific targets in mammalian cells, to exert their toxicity. This review focuses on the transport mechanisms of cholera toxin and botulinum neurotoxin complex. Cholera toxin is an ADP-ribosyltransferase toxin, and the covalent modification of heterotrimeric Gs protein in the cytosol leads to the activation of adenylyl cyclase and a sequence of events culminating in massive diarrheal disease. Here, we describe the structural features of this toxin and the transport pathway followed by this toxin from the plasma membrane to the cytosol of intestinal epithelial cells. Botulinum neurotoxin is a metalloprotease toxin that enters neurons, where it cleaves core proteins of the neuroexocytosis apparatus and elicits the inhibition of neurotransmitter release. The food-borne botulism is manifested when the neurotoxin is absorbed from the digestive tract, enters the blood stream, and reaches the cytosol of the peripheral nerves. We overview the structural organization and the long journey followed by this toxin.
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Affiliation(s)
- Yukako Fujinaga
- International Research Center for Infectious Diseases, Research Institute for Microbial Diseases, Osaka University, Yamada-oka 3-1, Suita, Osaka 565-0871.
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Chinnapen DJF, Chinnapen H, Saslowsky D, Lencer WI. Rafting with cholera toxin: endocytosis and trafficking from plasma membrane to ER. FEMS Microbiol Lett 2006; 266:129-37. [PMID: 17156122 PMCID: PMC3511785 DOI: 10.1111/j.1574-6968.2006.00545.x] [Citation(s) in RCA: 183] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cholera toxin (CT), and members of the AB(5) family of toxins enter host cells and hijack the cell's endogenous pathways to induce toxicity. CT binds to a lipid receptor on the plasma membrane (PM), ganglioside GM1, which has the ability to associate with lipid rafts. The toxin can then enter the cell by various modes of receptor-mediated endocytosis and traffic in a retrograde manner from the PM to the Golgi and the endoplasmic reticulum (ER). Once in the ER, a portion of the toxin is unfolded and retro-translocated to the cytosol so as to induce disease. GM1 is the vehicle that carries CT from PM to ER. Thus, the toxin pathway from PM to ER is a lipid-based sorting pathway, which is potentially meditated by the determinants of the GM1 ganglioside structure itself.
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Affiliation(s)
- Daniel J.-F. Chinnapen
- GI Cell Biology, Children’s Hospital, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | | | - David Saslowsky
- GI Cell Biology, Children’s Hospital, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Wayne I. Lencer
- GI Cell Biology, Children’s Hospital, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
- The Harvard Digestive Diseases Center, Boston, MA, USA
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Reig N, van der Goot FG. About lipids and toxins. FEBS Lett 2006; 580:5572-9. [PMID: 16962591 DOI: 10.1016/j.febslet.2006.08.033] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2006] [Revised: 08/08/2006] [Accepted: 08/09/2006] [Indexed: 11/25/2022]
Abstract
Many mono or multicellular organisms secrete soluble proteins, referred to as protein toxins, which alter the behavior of foreign, or target cells, possibly leading to their death. These toxins affect either the cell membrane by forming pores or modifying lipids, or some intracellular target. To reach this target, they must cross one of the cellular membranes, generally that of an intracellular organelle. As described in this minireview, lipids play crucial roles in the intoxication process of most if not all toxins, by allowing/promoting binding, endocytosis, trafficking and/or translocation into the cytoplasm.
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Affiliation(s)
- Núria Reig
- Ecole Polytechnique de Lausanne, Institute of Global Health, 1015 Lausanne, Switzerland
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Smith DC, Spooner RA, Watson PD, Murray JL, Hodge TW, Amessou M, Johannes L, Lord JM, Roberts LM. Internalized Pseudomonas exotoxin A can exploit multiple pathways to reach the endoplasmic reticulum. Traffic 2006; 7:379-93. [PMID: 16536737 DOI: 10.1111/j.1600-0854.2006.00391.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Receptor-mediated internalization to the endoplasmic reticulum (ER) and subsequent retro-translocation to the cytosol are essential sequential processes required for the intoxication of mammalian cells by Pseudomonas exotoxin A (PEx). The toxin binds the alpha2-macroglobulin receptor/low-density lipoprotein receptor-related protein. Here, we show that in HeLa cells, PEx recruits a proportion of this receptor to detergent-resistant microdomains (DRMs). Uptake of receptor-bound PEx involves transport steps both directly from early endosomes to the trans-Golgi network (TGN) independently of Rab9 function and from late endosomes to the TGN in a Rab9-dependent manner. Furthermore, treatments that simultaneously perturb both Arf1-dependent and Rab6-dependent retrograde pathways show that PEx can use multiple routes to reach the ER. The Rab6-dependent route has only been described previously for cargo with lipid-sorting signals. These findings suggest that partial localization of PEx within DRM permits a choice of trafficking routes consistent with a model that DRM-associated toxins reach the ER on a lipid-dependent sorting pathway whilst non-DRM-associated PEx exploits the previously characterized KDEL receptor-mediated uptake pathway. Thus, unexpectedly, an ER-directed toxin with a proteinaceous receptor shows promiscuity in its intracellular trafficking pathways, exploiting routes controlled by both lipid- and protein-sorting signals.
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Affiliation(s)
- Daniel C Smith
- Molecular Cell Biology Group, Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, UK
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