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Shtuhin-Rahav R, Olender A, Zlotkin-Rivkin E, Bouman EA, Danieli T, Nir-Keren Y, Weiss AM, Nandi I, Aroeti B. Enteropathogenic E. coli infection co-elicits lysosomal exocytosis and lytic host cell death. mBio 2023; 14:e0197923. [PMID: 38038448 PMCID: PMC10746156 DOI: 10.1128/mbio.01979-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 10/16/2023] [Indexed: 12/02/2023] Open
Abstract
IMPORTANCE Enteropathogenic Escherichia coli (EPEC) infection is a significant cause of gastroenteritis, mainly in children. Therefore, studying the mechanisms of EPEC infection is an important research theme. EPEC modulates its host cell life by injecting via a type III secretion machinery cell death modulating effector proteins. For instance, while EspF and Map promote mitochondrial cell death, EspZ antagonizes cell death. We show that these effectors also control lysosomal exocytosis, i.e., the trafficking of lysosomes to the host cell plasma membrane. Interestingly, the capacity of these effectors to induce or protect against cell death correlates completely with their ability to induce LE, suggesting that the two processes are interconnected. Modulating host cell death is critical for establishing bacterial attachment to the host and subsequent dissemination. Therefore, exploring the modes of LE involvement in host cell death is crucial for elucidating the mechanisms underlying EPEC infection and disease.
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Affiliation(s)
- Raisa Shtuhin-Rahav
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, The Edmond J. Safra Campus–Givat Ram, Jerusalem, Israel
- Department of Cell and Developmental Biology, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, The Edmond J. Safra Campus–Givat Ram, Jerusalem, Israel
| | - Aaron Olender
- Department of Cell and Developmental Biology, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, The Edmond J. Safra Campus–Givat Ram, Jerusalem, Israel
- The Alexander Grass Center for Bioengineering, The Hebrew University of Jerusalem, The Edmond J. Safra Campus–Givat Ram, Jerusalem, Israel
| | - Efrat Zlotkin-Rivkin
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, The Edmond J. Safra Campus–Givat Ram, Jerusalem, Israel
- Department of Cell and Developmental Biology, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, The Edmond J. Safra Campus–Givat Ram, Jerusalem, Israel
| | - Etan Amse Bouman
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, The Edmond J. Safra Campus–Givat Ram, Jerusalem, Israel
- Department of Cell and Developmental Biology, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, The Edmond J. Safra Campus–Givat Ram, Jerusalem, Israel
| | - Tsafi Danieli
- The Protein Production Facility, Wolfson Centre for Applied Structural Biology, The Hebrew University of Jerusalem, The Edmond J. Safra Campus–Givat Ram, Jerusalem, Israel
| | - Yael Nir-Keren
- The Protein Production Facility, Wolfson Centre for Applied Structural Biology, The Hebrew University of Jerusalem, The Edmond J. Safra Campus–Givat Ram, Jerusalem, Israel
| | - Aryeh M. Weiss
- Faculty of Engineering, Bar Ilan University, Ramat Gan, Israel
| | - Ipsita Nandi
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, The Edmond J. Safra Campus–Givat Ram, Jerusalem, Israel
- Department of Cell and Developmental Biology, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, The Edmond J. Safra Campus–Givat Ram, Jerusalem, Israel
| | - Benjamin Aroeti
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, The Edmond J. Safra Campus–Givat Ram, Jerusalem, Israel
- Department of Cell and Developmental Biology, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, The Edmond J. Safra Campus–Givat Ram, Jerusalem, Israel
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Haritan N, Bouman EA, Nandi I, Shtuhin-Rahav R, Zlotkin-Rivkin E, Danieli T, Melamed-Book N, Nir-Keren Y, Aroeti B. Topology and function of translocated EspZ. mBio 2023; 14:e0075223. [PMID: 37341483 PMCID: PMC10470495 DOI: 10.1128/mbio.00752-23] [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: 03/23/2023] [Accepted: 05/05/2023] [Indexed: 06/22/2023] Open
Abstract
EspZ and Tir are essential virulence effectors of enteropathogenic Escherichia coli (EPEC). EspZ, the second translocated effector, has been suggested to antagonize host cell death induced by the first translocated effector, Tir (translocated intimin receptor). Another characteristic of EspZ is its localization to host mitochondria. However, studies that explored the mitochondrial localization of EspZ have examined the ectopically expressed effector and not the more physiologically relevant translocated effector. Here, we confirmed the membrane topology of translocated EspZ at infection sites and the involvement of Tir in confining its localization to these sites. Unlike the ectopically expressed EspZ, the translocated EspZ did not colocalize with mitochondrial markers. Moreover, no correlation has been found between the capacity of ectopically expressed EspZ to target mitochondria and the ability of translocated EspZ to protect against cell death. Translocated EspZ may have to some extent diminished F-actin pedestal formation induced by Tir but has a marked effect on protecting against host cell death and on promoting host colonization by the bacteria. Taken together, our results suggest that EspZ plays an essential role in facilitating bacterial colonization, likely by antagonizing cell death mediated by Tir at the onset of bacterial infection. This activity of EspZ, which occurs by targeting host membrane components at infection sites, and not mitochondria, may contribute to successful bacterial colonization of the infected intestine. IMPORTANCE EPEC is an important human pathogen that causes acute infantile diarrhea. EspZ is an essential virulence effector protein translocated from the bacterium into the host cells. Detailed knowledge of its mechanisms of action is, therefore, critical for better understanding the EPEC disease. We show that Tir, the first translocated effector, confines the localization of EspZ, the second translocated effector, to infection sites. This activity is important for antagonizing the pro-cell death activity conferred by Tir. Moreover, we show that translocated EspZ leads to effective bacterial colonization of the host. Hence, our data suggest that translocated EspZ is essential because it confers host cell survival to allow bacterial colonization at an early stage of bacterial infection. It performs these activities by targeting host membrane components at infection sites. Identifying these targets is critical for elucidating the molecular mechanism underlying the EspZ activity and the EPEC disease.
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Affiliation(s)
- Nir Haritan
- Department of Biological Chemistry, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Etan Amse Bouman
- Department of Biological Chemistry, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ipsita Nandi
- Department of Biological Chemistry, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Raisa Shtuhin-Rahav
- Department of Biological Chemistry, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Efrat Zlotkin-Rivkin
- Department of Biological Chemistry, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Tsafi Danieli
- The Protein Production Facility, Wolfson Centre for Applied Structural Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Naomi Melamed-Book
- Bioimaging Unit, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Yael Nir-Keren
- The Protein Production Facility, Wolfson Centre for Applied Structural Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Benjamin Aroeti
- Department of Biological Chemistry, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
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Rollins J, Worthington T, Dransfield A, Whitney J, Stanford J, Hooke E, Hobson J, Wengler J, Hope S, Mizrachi D. Expression of Cell-Adhesion Molecules in E. coli: A High Throughput Screening to Identify Paracellular Modulators. Int J Mol Sci 2023; 24:9784. [PMID: 37372932 DOI: 10.3390/ijms24129784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 05/31/2023] [Accepted: 06/02/2023] [Indexed: 06/29/2023] Open
Abstract
Cell-adhesion molecules (CAMs) are responsible for cell-cell, cell-extracellular matrix, and cell-pathogen interactions. Claudins (CLDNs), occludin (OCLN), and junctional adhesion molecules (JAMs) are CAMs' components of the tight junction (TJ), the single protein structure tasked with safeguarding the paracellular space. The TJ is responsible for controlling paracellular permeability according to size and charge. Currently, there are no therapeutic solutions to modulate the TJ. Here, we describe the expression of CLDN proteins in the outer membrane of E. coli and report its consequences. When the expression is induced, the unicellular behavior of E. coli is replaced with multicellular aggregations that can be quantified using Flow Cytometry (FC). Our method, called iCLASP (inspection of cell-adhesion molecules aggregation through FC protocols), allows high-throughput screening (HTS) of small-molecules for interactions with CAMs. Here, we focused on using iCLASP to identify paracellular modulators for CLDN2. Furthermore, we validated those compounds in the mammalian cell line A549 as a proof-of-concept for the iCLASP method.
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Affiliation(s)
- Jay Rollins
- Department of Cell Biology and Physiology, College of Life Sciences, Brigham Young University, Provo, UT 84602, USA
| | - Tyler Worthington
- Department of Cell Biology and Physiology, College of Life Sciences, Brigham Young University, Provo, UT 84602, USA
| | - Allison Dransfield
- Department of Cell Biology and Physiology, College of Life Sciences, Brigham Young University, Provo, UT 84602, USA
| | - Jordan Whitney
- Department of Cell Biology and Physiology, College of Life Sciences, Brigham Young University, Provo, UT 84602, USA
| | - Jordan Stanford
- Department of Cell Biology and Physiology, College of Life Sciences, Brigham Young University, Provo, UT 84602, USA
| | - Emily Hooke
- Department of Cell Biology and Physiology, College of Life Sciences, Brigham Young University, Provo, UT 84602, USA
| | - Joseph Hobson
- Department of Cell Biology and Physiology, College of Life Sciences, Brigham Young University, Provo, UT 84602, USA
| | - Jacob Wengler
- Department of Cell Biology and Physiology, College of Life Sciences, Brigham Young University, Provo, UT 84602, USA
| | - Sandra Hope
- Department of Microbiology and Molecular Biology, College of Life Sciences, Brigham Young University, Provo, UT 84602, USA
| | - Dario Mizrachi
- Department of Cell Biology and Physiology, College of Life Sciences, Brigham Young University, Provo, UT 84602, USA
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Ramachandran RP, Nandi I, Haritan N, Zlotkin-Rivkin E, Keren Y, Danieli T, Lebendiker M, Melamed-Book N, Breuer W, Reichmann D, Aroeti B. EspH interacts with the host active Bcr related (ABR) protein to suppress RhoGTPases. Gut Microbes 2022; 14:2130657. [PMID: 36219160 PMCID: PMC9559323 DOI: 10.1080/19490976.2022.2130657] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Enteropathogenic Escherichia coli are bacterial pathogens that colonize the gut and cause severe diarrhea in humans. Upon intimate attachment to the intestinal epithelium, these pathogens translocate via a type III secretion system virulent proteins, termed effectors, into the host cells. These effectors manipulate diverse host cell organelles and functions for the pathogen's benefit. However, the precise mechanisms underlying their activities are not fully understood despite intensive research. EspH, a critical effector protein, has been previously reported to disrupt the host cell actin cytoskeleton by suppressing RhoGTPase guanine exchange factors. However, native host proteins targeted by EspH to mediate these activities remained unknown. Here, we identified the active Bcr related (ABR), a protein previously characterized to possess dual Rho guanine nucleotide exchange factor and GTPase activating protein (GAP) domains, as a native EspH interacting partner. These interactions are mediated by the effector protein's C-terminal 38 amino acid segment. The effector primarily targets the GAP domain of ABR to suppress Rac1 and Cdc42, host cell cytotoxicity, bacterial invasion, and filopodium formation at infection sites. Knockdown of ABR expression abolished the ability of EspH to suppress Rac1, Cdc42. Our studies unravel a novel mechanism by which host RhoGTPases are hijacked by bacterial effectors.
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Affiliation(s)
- Rachana Pattani Ramachandran
- Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ipsita Nandi
- Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Nir Haritan
- Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Efrat Zlotkin-Rivkin
- Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Yael Keren
- The Protein Production Facility, Wolfson Centre for Applied Structural Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Tsafi Danieli
- The Protein Production Facility, Wolfson Centre for Applied Structural Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Mario Lebendiker
- The Protein Production Facility, Wolfson Centre for Applied Structural Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Naomi Melamed-Book
- Bioimaging Unit, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - William Breuer
- Proteomics and Mass Spectrometry Unit, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Dana Reichmann
- Proteomics and Mass Spectrometry Unit, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel,Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Benjamin Aroeti
- Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel,CONTACT Benjamin Aroeti Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem91904, Israel
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Cegarra C, Cameron B, Chaves C, Dabdoubi T, Do TM, Genêt B, Roudières V, Shi Y, Tchepikoff P, Lesuisse D. An innovative strategy to identify new targets for delivering antibodies to the brain has led to the exploration of the integrin family. PLoS One 2022; 17:e0274667. [PMID: 36108060 PMCID: PMC9477330 DOI: 10.1371/journal.pone.0274667] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 09/01/2022] [Indexed: 11/19/2022] Open
Abstract
Background
Increasing brain exposure of biotherapeutics is key to success in central nervous system disease drug discovery. Accessing the brain parenchyma is especially difficult for large polar molecules such as biotherapeutics and antibodies because of the blood-brain barrier. We investigated a new immunization strategy to identify novel receptors mediating transcytosis across the blood-brain barrier.
Method
We immunized mice with primary non-human primate brain microvascular endothelial cells to obtain antibodies. These antibodies were screened for their capacity to bind and to be internalized by primary non-human primate brain microvascular endothelial cells and Human Cerebral Microvascular Endothelial Cell clone D3. They were further evaluated for their transcytosis capabilities in three in vitro blood-brain barrier models. In parallel, their targets were identified by two different methods and their pattern of binding to human tissue was investigated using immunohistochemistry.
Results
12 antibodies with unique sequence and internalization capacities were selected amongst more than six hundred. Aside from one antibody targeting Activated Leukocyte Cell Adhesion Molecule and one targeting Striatin3, most of the other antibodies recognized β1 integrin and its heterodimers. The antibody with the best transcytosis capabilities in all blood-brain barrier in vitro models and with the best binding capacity was an anti-αnβ1 integrin. In comparison, commercial anti-integrin antibodies performed poorly in transcytosis assays, emphasizing the originality of the antibodies derived here. Immunohistochemistry studies showed specific vascular staining on human and non-human primate tissues.
Conclusions
This transcytotic behavior has not previously been reported for anti-integrin antibodies. Further studies should be undertaken to validate this new mechanism in vivo and to evaluate its potential in brain delivery.
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Affiliation(s)
- Céline Cegarra
- Rare and Neurologic Diseases Research Therapeutic Area, Sanofi, Chilly Mazarin, France
- * E-mail:
| | | | - Catarina Chaves
- Rare and Neurologic Diseases Research Therapeutic Area, Sanofi, Chilly Mazarin, France
| | | | - Tuan-Minh Do
- Rare and Neurologic Diseases Research Therapeutic Area, Sanofi, Chilly Mazarin, France
| | - Bruno Genêt
- Integrated Drug Discovery, Sanofi, Vitry-Sur-Seine, France
| | - Valérie Roudières
- Rare and Neurologic Diseases Research Therapeutic Area, Sanofi, Chilly Mazarin, France
| | - Yi Shi
- Histology, Translational Sciences, Sanofi, Vitry-Sur-Seine, France
| | | | - Dominique Lesuisse
- Rare and Neurologic Diseases Research Therapeutic Area, Sanofi, Chilly Mazarin, France
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Mondal R, Saldaña-Ahuactzi Z, Soria-Bustos J, Schultz A, Yañez-Santos JA, Laguna YM, Cedillo-Ramírez ML, Girón JA. The EcpD Tip Adhesin of the Escherichia coli Common Pilus Mediates Binding of Enteropathogenic E. coli to Extracellular Matrix Proteins. Int J Mol Sci 2022; 23:ijms231810350. [PMID: 36142263 PMCID: PMC9499635 DOI: 10.3390/ijms231810350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 08/04/2022] [Accepted: 08/30/2022] [Indexed: 11/16/2022] Open
Abstract
The attachment of enteropathogenic Escherichia coli (EPEC) to intestinal epithelial cells is facilitated by several adhesins; however, the individual host-cell receptors for pili-mediated adherence have not been fully characterized. In this study, we evaluated the hypothesis that the E. coli common pilus (ECP) tip adhesin protein EcpD mediates attachment of EPEC to several extracellular matrix (ECM) glycoproteins (fibronectin, laminin, collagens I and IV, and mucin). We found that the ΔecpA mutant, which lacks production of the EcpA filament but retains EcpD on the surface, adhered to these glycoproteins below the wild-type levels, while the ΔecpD mutant, which does not display EcpA or EcpD, bound significantly less to these host glycoproteins. In agreement, a purified recombinant EcpD subunit bound significantly more than EcpA to laminin, fibronectin, collagens I and IV, and mucin in a dose-dependent manner. These are compelling data that strongly suggest that ECP-producing EPEC may bind to host ECM glycoproteins and mucins through the tip adhesin protein EcpD. This study highlights the versatility of EPEC to bind to different host proteins and suggests that the interaction of ECP with the host’s ECM glycoproteins may facilitate colonization of the intestinal mucosal epithelium.
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Affiliation(s)
- Rajesh Mondal
- ICMR-Bhopal Memorial Hospital and Research Center, Bhopal 462038, India
| | - Zeus Saldaña-Ahuactzi
- Paul G. Allen School for Global Health, College of Veterinary Medicine, Washington State University, Pullman, WA 99164, USA
| | - Jorge Soria-Bustos
- Facultad de Medicina Mexicali, Universidad Autónoma de Baja California, Mexicali 21100, Mexico
| | - Andrew Schultz
- Department of Microbiology and Molecular Genetics, University of Florida, Gainesville, FL 32611, USA
| | - Jorge A. Yañez-Santos
- Facultad de Estomatología, Benemérita Universidad Autónoma de Puebla, Puebla 72592, Mexico
| | - Ygnacio Martínez Laguna
- Centro de Investigación en Ciencias Microbiológicas, Benemérita Universidad Autónoma de Puebla, Puebla 72592, Mexico
| | - María L. Cedillo-Ramírez
- Centro de Detección Biomolecular, Benemérita Universidad Autónoma de Puebla, Puebla 72592, Mexico
| | - Jorge A. Girón
- Centro de Detección Biomolecular, Benemérita Universidad Autónoma de Puebla, Puebla 72592, Mexico
- Correspondence:
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Factors Affecting Spontaneous Endocytosis and Survival of Probiotic Lactobacilli in Human Intestinal Epithelial Cells. Microorganisms 2022; 10:microorganisms10061142. [PMID: 35744660 PMCID: PMC9230732 DOI: 10.3390/microorganisms10061142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 05/25/2022] [Accepted: 05/30/2022] [Indexed: 11/29/2022] Open
Abstract
Mutualistic bacteria have different forms of interaction with the host. In contrast to the invasion of pathogenic bacteria, naturally occurring internalization of commensal bacteria has not been studied in depth. Three in vitro methods, gentamicin protection, flow cytometry and confocal laser scanning microscopy, have been implemented to accurately assess the internalization of two lactobacillus strains—Lacticaseibacillus paracasei BL23 and Lacticaseibacillus rhamnosus GG—in Caco-2 and T84 intestinal epithelial cells (IECs) under a variety of physiological conditions and with specific inhibitors. First and most interesting, internalization occurred at a variable rate that depends on the bacterial strain and IEC line, and the most efficient was BL23 internalization by T84 and, second, efficient internalization required active IEC proliferation, as it improved naturally at the early confluence stages and by stimulation with epidermal growth factor (EGF). IFN-γ is bound to innate immune responses and autolysis; this cytokine had a significant effect on internalization, as shown by flow cytometry, but increased internalization was not perceived in all conditions, possibly because it was also stimulating autolysis and, as a consequence, the viability of bacteria after uptake could be affected. Bacterial uptake required actin polymerization, as shown by cytochalasin D inhibition, and it was partially bound to clathrin and caveolin dependent endocytosis. It also showed partial inhibition by ML7 indicating the involvement of cholesterol lipid rafts and myosin light chain kinase (MLCK) activation, at least in the LGG uptake by Caco-2. Most interestingly, bacteria remained viable inside the IEC for as long as 72 h without damaging the epithelial cells, and paracellular transcytosis was observed. These results stressed the fact that internalization of commensal and mutualistic bacteria is a natural, nonpathogenic process that may be relevant in crosstalk processes between the intestinal populations and the host, and future studies could determine its connection to processes such as commensal tolerance, resilience of microbial populations or transorganic bacterial migration.
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Mitotic Arrest-Deficient 2 Like 2 (MAD2L2) Interacts with Escherichia coli Effector Protein EspF. Life (Basel) 2021; 11:life11090971. [PMID: 34575120 PMCID: PMC8469580 DOI: 10.3390/life11090971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/10/2021] [Accepted: 09/10/2021] [Indexed: 12/01/2022] Open
Abstract
Enteropathogenic (EPEC) and Enterohemorrhagic (EHEC) Escherichia coli are considered emerging zoonotic pathogens of worldwide distribution. The pathogenicity of the bacteria is conferred by multiple virulence determinants, including the locus of enterocyte effacement (LEE) pathogenicity island, which encodes a type III secretion system (T3SS) and effector proteins, including the multifunctional secreted effector protein (EspF). EspF sequences differ between EPEC and EHEC serotypes in terms of the number and residues of SH3-binding polyproline-rich repeats and N-terminal localization sequence. The aim of this study was to discover additional cellular interactions of EspF that may play important roles in E. coli colonization using the Yeast two-hybrid screening system (Y2H). Y2H screening identified the anaphase-promoting complex inhibitor Mitotic Arrest-Deficient 2 Like 2 (MAD2L2) as a host protein that interacts with EspF. Using LUMIER assays, MAD2L2 was shown to interact with EspF variants from EHEC O157:H7 and O26:H11 as well as EPEC O127:H6. MAD2L2 is targeted by the non-homologous Shigella effector protein invasion plasmid antigen B (IpaB) to halt the cell cycle and limit epithelial cell turnover. Therefore, we postulate that interactions between EspF and MAD2L2 serve a similar function in promoting EPEC and EHEC colonization, since cellular turnover is a key method for bacteria removal from the epithelium. Future work should investigate the biological importance of this interaction that could promote the colonization of EPEC and EHEC E. coli in the host.
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Nandi I, Aroeti L, Ramachandran RP, Kassa EG, Zlotkin-Rivkin E, Aroeti B. Type III secreted effectors that target mitochondria. Cell Microbiol 2021; 23:e13352. [PMID: 33960116 DOI: 10.1111/cmi.13352] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 04/22/2021] [Accepted: 04/29/2021] [Indexed: 01/05/2023]
Abstract
A type III secretion system (T3SS) is used by Gram-negative bacterial pathogens to secrete and translocate a battery of proteins, termed effectors, from the bacteria directly into the host cells. These effectors, which are thought to play a key role in bacterial virulence, hijack and modify the activity of diverse host cell organelles, including mitochondria. Mitochondria-the energy powerhouse of the cell-are important cell organelles that play role in numerous critical cellular processes, including the initiation of apoptosis and the induction of innate immunity. Therefore, it is not surprising that pathogenic bacteria use mitochondrially targeted effectors to control host cell death and immunity pathways. Surprisingly, however, we found that despite their importance, only a limited number of type III secreted effectors have been characterised to target host mitochondria, and the mechanisms underlying their mitochondrial activity have not been sufficiently analysed. These include effectors secreted by the enteric attaching and effacing (A/E), Salmonella and Shigella bacterial pathogens. Here we give an overview of key findings, present gaps in knowledge and hypotheses concerning the mode by which these type III secreted effectors control the host and the bacterial cell life (and death) through targeting mitochondria.
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Affiliation(s)
- Ipsita Nandi
- Department of Cell and Developmental Biology, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Lior Aroeti
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Rachana Pattani Ramachandran
- Department of Cell and Developmental Biology, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ephrem G Kassa
- Department of Cell and Developmental Biology, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Efrat Zlotkin-Rivkin
- Department of Cell and Developmental Biology, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Benjamin Aroeti
- Department of Cell and Developmental Biology, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem, Jerusalem, Israel
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10
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Lv H, Li Y, Xue C, Dong N, Bi C, Shan A. Aquaporin: targets for dietary nutrients to regulate intestinal health. J Anim Physiol Anim Nutr (Berl) 2021; 106:167-180. [PMID: 33811387 DOI: 10.1111/jpn.13539] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 12/07/2020] [Accepted: 02/07/2021] [Indexed: 12/22/2022]
Abstract
Aquaporins (AQP) are a class of water channel membrane proteins that are widely expressed in the gut. The biological functions of aquaporins, which regulate the absorption and secretion of water molecules and small solutes, maintain the stable state of the intestine, regulate cell proliferation and migration, participate in the process of intestinal inflammation, and mediate tumorigenesis, demonstrate the physiological significance of these channels in intestinal health. The pathology of many intestinal diseases is associated with changes in the location and expression of aquaporins, such as intestinal infection, which can change the expression and distribution of AQPs in intestinal tissues/cells by affecting cytokines and chemokines. This can lead to various intestinal diseases such as diarrhoea, which also suggests the importance of aquaporins in the prevention and treatment of intestinal diseases. This review summarizes the relationship between aquaporins and intestinal physiology and diseases and focuses on drugs (such as plant extracts) or diets that can regulate intestinal health by regulating aquaporins. It provides a basis for establishing aquaporins as biomarkers and therapeutic targets for intestinal health.
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Affiliation(s)
- Hao Lv
- Institute of Animal Nutrition, Northeast Agricultural University, Harbin, China
| | - Ying Li
- Institute of Animal Nutrition, Northeast Agricultural University, Harbin, China
| | - Chenyu Xue
- Institute of Animal Nutrition, Northeast Agricultural University, Harbin, China
| | - Na Dong
- Institute of Animal Nutrition, Northeast Agricultural University, Harbin, China
| | - Chongpeng Bi
- Institute of Animal Nutrition, Northeast Agricultural University, Harbin, China
| | - Anshan Shan
- Institute of Animal Nutrition, Northeast Agricultural University, Harbin, China
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Mitochondrial Targeting of the Enteropathogenic Escherichia coli Map Triggers Calcium Mobilization, ADAM10-MAP Kinase Signaling, and Host Cell Apoptosis. mBio 2020; 11:mBio.01397-20. [PMID: 32934081 PMCID: PMC7492733 DOI: 10.1128/mbio.01397-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Enteropathogenic E. coli (EPEC) is an important human diarrhea-causing bacterium. The pathogenic effects of EPEC largely depend upon its ability to inject a series of proteins, termed effectors, into the host cells. One such effector is the mitochondrion-associated protein (Map). Map has been shown to induce actin-rich projections (i.e., filopodia) on the infected cell surface and activate a Rho GTPase enzyme termed Cdc42. Nonetheless, although most injected Map localizes to host mitochondria, its functions in the mitochondria remain unknown. Here, we show that Map targeting of mitochondria stimulates the disruption of mitochondrial membrane potential to induce Ca2+ efflux into the host cytoplasm. The efflux stimulates the activity of a protein termed ADAM10, which induces activation of a mitogen-activated protein kinase cascade leading to host cell apoptosis. As apoptosis plays a central role in host-pathogen interactions, our findings provide novel insights into the functions of mitochondrial Map in promoting the EPEC disease. The ability of diarrheagenic bacterial pathogens, such as enteropathogenic Escherichia coli (EPEC), to modulate the activity of mitogen-activated protein kinases (MAPKs) and cell survival has been suggested to benefit bacterial colonization and infection. However, our understanding of the mechanisms by which EPEC modulate these functions is incomplete. In this study, we show that the EPEC type III secreted effector Map stimulates the sheddase activity of the disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) and the ERK and p38 MAPK signaling cascades. Remarkably, all these activities were dependent upon the ability of Map to target host mitochondria, mainly via its mitochondrial toxicity region (MTR). Map targeting of mitochondria disrupted the mitochondrial membrane potential, causing extrusion of mitochondrial Ca2+ into the host cell cytoplasm. We also found that Map targeting of mitochondria is essential for triggering host cell apoptosis. Based on these findings, we propose a model whereby Map imported into mitochondria causes mitochondrial dysfunction and Ca2+ efflux into the host cytoplasm. Since Ca2+ has been reported to promote ADAM10 activation, the acute elevation of Ca2+ in the cytoplasm may stimulate the ADAM10 sheddase activity, resulting in the release of epidermal growth factors that stimulate the ERK signaling cascade. As p38 activity is also Ca2+ sensitive, elevation in cytoplasmic Ca2+ may independently also activate p38. We hypothesize that Map-dependent MAPK activation, combined with Map-mediated mitochondrial dysfunction, evokes mitochondrial host cell apoptosis, potentially contributing to EPEC colonization and infection of the gut.
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12
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Enteropathogenic Escherichia coli (EPEC) Recruitment of PAR Polarity Protein Atypical PKCζ to Pedestals and Cell-Cell Contacts Precedes Disruption of Tight Junctions in Intestinal Epithelial Cells. Int J Mol Sci 2020; 21:ijms21020527. [PMID: 31947656 PMCID: PMC7014222 DOI: 10.3390/ijms21020527] [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] [Received: 12/13/2019] [Revised: 01/09/2020] [Accepted: 01/10/2020] [Indexed: 12/26/2022] Open
Abstract
Enteropathogenic Escherichia coli (EPEC) uses a type three secretion system to inject effector proteins into host intestinal epithelial cells, causing diarrhea. EPEC induces the formation of pedestals underlying attached bacteria, disrupts tight junction (TJ) structure and function, and alters apico-basal polarity by redistributing the polarity proteins Crb3 and Pals1, although the mechanisms are unknown. Here we investigate the temporal relationship of PAR polarity complex and TJ disruption following EPEC infection. EPEC recruits active aPKCζ, a PAR polarity protein, to actin within pedestals and at the plasma membrane prior to disrupting TJ. The EPEC effector EspF binds the endocytic protein sorting nexin 9 (SNX9). This interaction impacts actin pedestal organization, recruitment of active aPKCζ to actin at cell–cell borders, endocytosis of JAM-A S285 and occludin, and TJ barrier function. Collectively, data presented herein support the hypothesis that EPEC-induced perturbation of TJ is a downstream effect of disruption of the PAR complex and that EspF binding to SNX9 contributes to this phenotype. aPKCζ phosphorylates polarity and TJ proteins and participates in actin dynamics. Therefore, the early recruitment of aPKCζ to EPEC pedestals and increased interaction with actin at the membrane may destabilize polarity complexes ultimately resulting in perturbation of TJ.
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