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Semenikhina M, Fedoriuk M, Stefanenko M, Klemens CA, Cherezova A, Marshall B, Hall G, Levchenko V, Solanki AK, Lipschutz JH, Ilatovskaya DV, Staruschenko A, Palygin O. β-Arrestin pathway activation by selective ATR1 agonism promotes calcium influx in podocytes, leading to glomerular damage. Clin Sci (Lond) 2023; 137:1789-1804. [PMID: 38051199 DOI: 10.1042/cs20230313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 10/24/2023] [Accepted: 12/05/2023] [Indexed: 12/07/2023]
Abstract
Angiotensin receptor blockers (ARBs) are the first-line treatment for hypertension; they act by inhibiting signaling through the angiotensin 1 receptor (AT1R). Recently, a novel biased AT1R agonist, TRV120027 (TRV), which selectively activates the β-arrestin cascade and blocks the G-protein-coupled receptor pathway has been proposed as a potential blood pressure medication. Here, we explored the effects of TRV and associated β-arrestin signaling in podocytes, essential cells of the kidney filter. We used human podocyte cell lines to determine β-arrestin's involvement in calcium signaling and cytoskeletal reorganization and Dahl SS rats to investigate the chronic effects of TRV administration on glomerular health. Our experiments indicate that the TRV-activated β-arrestin pathway promotes the rapid elevation of intracellular Ca2+ in a dose-dependent manner. Interestingly, the amplitude of β-arrestin-mediated Ca2+ influx was significantly higher than the response to similar Ang II concentrations. Single-channel analyses show rapid activation of transient receptor potential canonical (TRPC) channels following acute TRV application. Furthermore, the pharmacological blockade of TRPC6 significantly attenuated the β-arrestin-mediated Ca2+ influx. Additionally, prolonged activation of the β-arrestin pathway in podocytes resulted in pathological actin cytoskeleton rearrangements, higher apoptotic cell markers, and augmented glomerular damage. TRV-activated β-arrestin signaling in podocytes may promote TRPC6 channel-mediated Ca2+ influx, foot process effacement, and apoptosis, possibly leading to severe defects in glomerular filtration barrier integrity and kidney health. Under these circumstances, the potential therapeutic application of TRV for hypertension treatment requires further investigation to assess the balance of the benefits versus possible deleterious effects and off-target damage.
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Affiliation(s)
- Marharyta Semenikhina
- Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, SC, U.S.A
| | - Mykhailo Fedoriuk
- Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, SC, U.S.A
| | - Mariia Stefanenko
- Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, SC, U.S.A
| | - Christine A Klemens
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, U.S.A
- Hypertension and Kidney Research Center, University of South Florida, Tampa, FL, U.S.A
| | - Alena Cherezova
- Department of Physiology, Medical College of Georgia, Augusta University, GA, U.S.A
| | - Brendan Marshall
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, GA, U.S.A
| | - Gentzon Hall
- Division of Nephrology, Department of Internal Medicine, Duke University School of Medicine, Durham, NC, U.S.A
- Duke Molecular Physiology Institute, Duke University, Durham, NC, U.S.A
| | - Vladislav Levchenko
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, U.S.A
| | - Ashish K Solanki
- Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, SC, U.S.A
| | - Joshua H Lipschutz
- Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, SC, U.S.A
- Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC, U.S.A
| | - Daria V Ilatovskaya
- Department of Physiology, Medical College of Georgia, Augusta University, GA, U.S.A
| | - Alexander Staruschenko
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, U.S.A
- Hypertension and Kidney Research Center, University of South Florida, Tampa, FL, U.S.A
- James A. Haley Veterans' Hospital, Tampa, FL, U.S.A
| | - Oleg Palygin
- Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, SC, U.S.A
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, U.S.A
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Chen YM, Burrough E. The Effects of Swine Coronaviruses on ER Stress, Autophagy, Apoptosis, and Alterations in Cell Morphology. Pathogens 2022; 11:pathogens11080940. [PMID: 36015060 PMCID: PMC9416022 DOI: 10.3390/pathogens11080940] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/14/2022] [Accepted: 08/15/2022] [Indexed: 11/17/2022] Open
Abstract
Swine coronaviruses include the following six members, namely porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV), porcine delta coronavirus (PDCoV), swine acute diarrhea syndrome coronavirus (SADS-CoV), porcine hemagglutinating encephalomyelitis virus (PHEV), and porcine respiratory coronavirus (PRCV). Clinically, PEDV, TGEV, PDCoV, and SADS-CoV cause enteritis, whereas PHEV induces encephalomyelitis, and PRCV causes respiratory disease. Years of studies reveal that swine coronaviruses replicate in the cellular cytoplasm exerting a wide variety of effects on cells. Some of these effects are particularly pertinent to cell pathology, including endoplasmic reticulum (ER) stress, unfolded protein response (UPR), autophagy, and apoptosis. In addition, swine coronaviruses are able to induce cellular changes, such as cytoskeletal rearrangement, alterations of junctional complexes, and epithelial-mesenchymal transition (EMT), that render enterocytes unable to absorb nutrients normally, resulting in the loss of water, ions, and protein into the intestinal lumen. This review aims to describe the cellular changes in swine coronavirus-infected cells and to aid in understanding the pathogenesis of swine coronavirus infections. This review also explores how the virus exerted subcellular and molecular changes culminating in the clinical and pathological findings observed in the field.
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Affiliation(s)
- Ya-Mei Chen
- College of Veterinary Medicine, National Pingtung University of Science and Technology, Neipu, Pingtung County 912301, Taiwan
- Correspondence:
| | - Eric Burrough
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
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Lv X, Li Z, Guan J, Hu S, Zhang J, Lan Y, Zhao K, Lu H, Song D, He H, Gao F, He W. Porcine Hemagglutinating Encephalomyelitis Virus Activation of the Integrin α5β1-FAK-Cofilin Pathway Causes Cytoskeletal Rearrangement To Promote Its Invasion of N2a Cells. J Virol 2019; 93:e01736-18. [PMID: 30541856 DOI: 10.1128/JVI.01736-18] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 12/05/2018] [Indexed: 12/22/2022] Open
Abstract
PHEV, a member of the Coronaviridae family, is a typical neurotropic virus that primarily affects the nervous system of piglets to produce typical neurological symptoms. However, the mechanism of nerve damage caused by the virus has not been fully elucidated. Actin is an important component of the cytoskeleton of eukaryotic cells and serves as the first obstacle to the entry of pathogens into host cells. Additionally, the morphological structure and function of nerve cells depend on the dynamic regulation of the actin skeleton. Therefore, exploring the mechanism of neuronal injury induced by PHEV from the perspective of the actin cytoskeleton not only helps elucidate the pathogenesis of PHEV but also provides a theoretical basis for the search for new antiviral targets. This is the first report to define a mechanistic link between alterations in signaling from cytoskeleton pathways and the mechanism of PHEV invading nerve cells. Porcine hemagglutinating encephalomyelitis virus (PHEV) is a highly neurotropic virus that causes diffuse neuronal infection with neurological damage and high mortality. Virus-induced cytoskeletal dynamics are thought to be closely related to this type of nerve damage. Currently, the regulation pattern of the actin cytoskeleton and its molecular mechanism remain unclear when PHEV enters the host cells. Here, we demonstrate that entry of PHEV into N2a cells induces a biphasic remodeling of the actin cytoskeleton and a dynamic change in cofilin activity. Viral entry is affected by the disruption of actin kinetics or alteration of cofilin activity. PHEV binds to integrin α5β1 and then initiates the integrin α5β1-FAK signaling pathway, leading to virus-induced early cofilin phosphorylation and F-actin polymerization. Additionally, Ras-related C3 botulinum toxin substrate 1 (Rac1), cell division cycle 42 (Cdc42), and downstream regulatory gene p21-activated protein kinases (PAKs) are recruited as downstream mediators of PHEV-induced dynamic changes of the cofilin activity pathway. In conclusion, we demonstrate that PHEV utilizes the integrin α5β1-FAK-Rac1/Cdc42-PAK-LIMK-cofilin pathway to cause an actin cytoskeletal rearrangement to promote its own invasion, providing theoretical support for the development of PHEV pathogenic mechanisms and new antiviral targets. IMPORTANCE PHEV, a member of the Coronaviridae family, is a typical neurotropic virus that primarily affects the nervous system of piglets to produce typical neurological symptoms. However, the mechanism of nerve damage caused by the virus has not been fully elucidated. Actin is an important component of the cytoskeleton of eukaryotic cells and serves as the first obstacle to the entry of pathogens into host cells. Additionally, the morphological structure and function of nerve cells depend on the dynamic regulation of the actin skeleton. Therefore, exploring the mechanism of neuronal injury induced by PHEV from the perspective of the actin cytoskeleton not only helps elucidate the pathogenesis of PHEV but also provides a theoretical basis for the search for new antiviral targets. This is the first report to define a mechanistic link between alterations in signaling from cytoskeleton pathways and the mechanism of PHEV invading nerve cells.
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Tong H, Qi D, Guan X, Jiang G, Liao Z, Zhang X, Chen P, Li N, Wu M. c-Abl tyrosine kinase regulates neutrophil crawling behavior under fluid shear stress via Rac/PAK/LIMK/cofilin signaling axis. J Cell Biochem 2017; 119:2806-2817. [PMID: 29058761 DOI: 10.1002/jcb.26453] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 10/17/2017] [Indexed: 12/13/2022]
Abstract
The excessive recruitment and improper activation of polymorphonuclear neutrophils (PMNs) often induces serious injury of host tissues, leading to inflammatory disorders. Therefore, to understand the molecular mechanism on neutrophil recruitment possesses essential pathological and physiological importance. In this study, we found that physiological shear stress induces c-Abl kinase activation in neutrophils, and c-Abl kinase inhibitor impaired neutrophil crawling behavior on ICAM-1. We further identified Vav1 was a downstream effector phosphorylated at Y174 and Y267. Once activated, c-Abl kinase regulated the activity of Vav1, which further affected Rac1/PAK1/LIMK1/cofilin signaling pathway. Here, we demonstrate a novel signaling function and critical role of c-Abl kinase during neutrophil crawling under physiological shear by regulating Vav1. These findings provide a promising treatment strategy for inflammation-related disease by inactivation of c-Abl kinase to restrict neutrophil recruitment.
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Affiliation(s)
- Haibin Tong
- College of Life and Environmental Science, Wenzhou University, Wenzhou, China.,Jilin Provincial Key Laboratory of Molecular Geriatric Medicine, Life Science Research Center, Beihua University, Jilin, China
| | - Dake Qi
- Faculty of Medicine, Division of Biomedical Sciences, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Xingang Guan
- Jilin Provincial Key Laboratory of Molecular Geriatric Medicine, Life Science Research Center, Beihua University, Jilin, China
| | - Guiquan Jiang
- Jilin Provincial Key Laboratory of Molecular Geriatric Medicine, Life Science Research Center, Beihua University, Jilin, China
| | - Zhiyong Liao
- College of Life and Environmental Science, Wenzhou University, Wenzhou, China
| | - Xu Zhang
- College of Life and Environmental Science, Wenzhou University, Wenzhou, China
| | - Peichao Chen
- College of Life and Environmental Science, Wenzhou University, Wenzhou, China
| | - Nan Li
- College of Life and Environmental Science, Wenzhou University, Wenzhou, China
| | - Mingjiang Wu
- College of Life and Environmental Science, Wenzhou University, Wenzhou, China
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Lin J, Shi Y, Peng H, Shen X, Thomas S, Wang Y, Truong LD, Dryer SE, Hu Z, Xu J. Loss of PTEN promotes podocyte cytoskeletal rearrangement, aggravating diabetic nephropathy. J Pathol 2015; 236:30-40. [PMID: 25641678 DOI: 10.1002/path.4508] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 12/21/2014] [Accepted: 01/08/2015] [Indexed: 12/17/2022]
Abstract
In diabetic nephropathy (DN), podocyte cytoskeletal rearrangement occurs followed by podocyte effacement and the development of proteinuria. PTEN (phosphatase and tensin homologue) is a ubiquitously expressed phosphatase that plays a critical role in cell proliferation, cytoskeletal rearrangement, and motility. In mouse models of diabetes mellitus, PTEN expression is reportedly decreased in mesangial cells, contributing to expansion of the mesangial matrix, but how PTEN in the podocyte influences the development of DN is unknown. We observed that PTEN expression is down-regulated in the podocytes of diabetic db/db mice and patients with DN. In cultured podocytes, PTEN inhibition caused actin cytoskeletal rearrangement and this response was associated with unbalanced activation of the small GTPases Rac1/Cdc42 and RhoA. In mice treated with PTEN inhibitor, actin cytoskeletal rearrangement occurred in podocytes and was accompanied by increased albumin excretion. We also created mice with an inducible deletion of PTEN selectively in podocytes. These mice exhibited increased albumin excretion and moderate foot process effacement. When the mice were challenged with a high fat diet, podocyte-specific knockout of PTEN resulted in substantially increased proteinuria and glomeruloclerosis compared to control mice fed a high fat diet or mice with PTEN deletion fed a normal diet. These results indicate that PTEN is involved in the regulation of cytoskeletal rearrangement in podocytes and that loss of PTEN predisposes to the development of proteinuria and DN.
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Affiliation(s)
- Jamie Lin
- Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA
| | - Yuanyuan Shi
- Nephrology Division, Second Hospital of Shanxi Medical University, Taiyuan, China
| | - Hui Peng
- Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA
| | - Xiaojie Shen
- Renal Sections, Changhai Hospital, Shanghai, China
| | - Sandhya Thomas
- Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA
| | - Yanlin Wang
- Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA
| | - Luan D Truong
- Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA
| | - Stuart E Dryer
- Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA.,Departments of Biology and Biochemistry, University of Houston, Houston, Texas, USA
| | - Zhaoyong Hu
- Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA.,Nephrology Division, Second Hospital of Shanxi Medical University, Taiyuan, China
| | - Jing Xu
- Renal Sections, Changhai Hospital, Shanghai, China
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6
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Zhang J, Shehabeldin A, da Cruz LA, Butler J, Somani AK, McGavin M, Kozieradzki I, dos Santos AO, Nagy A, Grinstein S, Penninger JM, Siminovitch KA. Antigen receptor-induced activation and cytoskeletal rearrangement are impaired in Wiskott-Aldrich syndrome protein-deficient lymphocytes. J Exp Med 1999; 190:1329-42. [PMID: 10544204 PMCID: PMC2195687 DOI: 10.1084/jem.190.9.1329] [Citation(s) in RCA: 290] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The Wiskott-Aldrich syndrome protein (WASp) has been implicated in modulation of lymphocyte activation and cytoskeletal reorganization. To address the mechanisms whereby WASp subserves such functions, we have examined WASp roles in lymphocyte development and activation using mice carrying a WAS null allele (WAS(-)(/)(-)). Enumeration of hemopoietic cells in these animals revealed total numbers of thymocytes, peripheral B and T lymphocytes, and platelets to be significantly diminished relative to wild-type mice. In the thymus, this abnormality was associated with impaired progression from the CD44(-)CD25(+) to the CD44(-)CD25(-) stage of differentiation. WASp-deficient thymocytes and T cells also exhibited impaired proliferation and interleukin (IL)-2 production in response to T cell antigen receptor (TCR) stimulation, but proliferated normally in response to phorbol ester/ionomycin. This defect in TCR signaling was associated with a reduction in TCR-evoked upregulation of the early activation marker CD69 and in TCR-triggered apoptosis. While induction of TCR-zeta, ZAP70, and total protein tyrosine phosphorylation as well as mitogen-activated protein kinase (MAPK) and stress-activated protein/c-Jun NH(2)-terminal kinase (SAPK/JNK) activation appeared normal in TCR-stimulated WAS(-)(/)(-) cells, TCR-evoked increases in intracellular calcium concentration were decreased in WASp-deficient relative to wild-type cells. WAS(-)(/)(-) lymphocytes also manifested a marked reduction in actin polymerization and both antigen receptor capping and endocytosis after TCR stimulation, whereas WAS(-)(/)(-) neutrophils exhibited reduced phagocytic activity. Together, these results provide evidence of roles for WASp in driving lymphocyte development, as well as in the translation of antigen receptor stimulation to proliferative or apoptotic responses, cytokine production, and cytoskeletal rearrangement. The data also reveal a role for WASp in modulating endocytosis and phagocytosis and, accordingly, suggest that the immune deficit conferred by WASp deficiency reflects the disruption of a broad range of cellular behaviors.
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Affiliation(s)
- Jinyi Zhang
- Department of Medicine, University of Toronto, Ontario, Canada M5G 1X5
- Department of Immunology, University of Toronto, Ontario, Canada M5G 1X5
- Department of Medical Genetics and Microbiology, University of Toronto, Ontario, Canada M5G 1X5
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada M5G 1X5
| | - Amro Shehabeldin
- Department of Medicine, University of Toronto, Ontario, Canada M5G 1X5
- Department of Immunology, University of Toronto, Ontario, Canada M5G 1X5
- Department of Medical Genetics and Microbiology, University of Toronto, Ontario, Canada M5G 1X5
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada M5G 1X5
| | - Luis A.G. da Cruz
- Department of Medicine, University of Toronto, Ontario, Canada M5G 1X5
- Department of Immunology, University of Toronto, Ontario, Canada M5G 1X5
- Department of Medical Genetics and Microbiology, University of Toronto, Ontario, Canada M5G 1X5
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada M5G 1X5
| | - Jeffrey Butler
- Department of Biochemistry, University of Toronto, Ontario, Canada M5G 1X5
- Division of Cell Biology, Research Institute, Hospital for Sick Children
| | - Ally-Khan Somani
- Department of Medicine, University of Toronto, Ontario, Canada M5G 1X5
- Department of Immunology, University of Toronto, Ontario, Canada M5G 1X5
- Department of Medical Genetics and Microbiology, University of Toronto, Ontario, Canada M5G 1X5
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada M5G 1X5
| | - Mary McGavin
- Department of Medicine, University of Toronto, Ontario, Canada M5G 1X5
- Department of Immunology, University of Toronto, Ontario, Canada M5G 1X5
- Department of Medical Genetics and Microbiology, University of Toronto, Ontario, Canada M5G 1X5
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada M5G 1X5
| | - Ivona Kozieradzki
- Department of Immunology, University of Toronto, Ontario, Canada M5G 1X5
- Department of Medical Biophysics, University of Toronto, Ontario, Canada M5G 1X5
- Amgen Institute, Ontario Cancer Institute, Toronto, Ontario, Canada M5G 2C1
| | - Antonio O. dos Santos
- Department of Immunology, University of Toronto, Ontario, Canada M5G 1X5
- Department of Medical Biophysics, University of Toronto, Ontario, Canada M5G 1X5
- Amgen Institute, Ontario Cancer Institute, Toronto, Ontario, Canada M5G 2C1
| | - Andras Nagy
- Department of Medical Genetics and Microbiology, University of Toronto, Ontario, Canada M5G 1X5
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada M5G 1X5
| | - Sergio Grinstein
- Department of Biochemistry, University of Toronto, Ontario, Canada M5G 1X5
- Division of Cell Biology, Research Institute, Hospital for Sick Children
| | - Josef M. Penninger
- Department of Immunology, University of Toronto, Ontario, Canada M5G 1X5
- Department of Medical Biophysics, University of Toronto, Ontario, Canada M5G 1X5
- Amgen Institute, Ontario Cancer Institute, Toronto, Ontario, Canada M5G 2C1
| | - Katherine A. Siminovitch
- Department of Medicine, University of Toronto, Ontario, Canada M5G 1X5
- Department of Immunology, University of Toronto, Ontario, Canada M5G 1X5
- Department of Medical Genetics and Microbiology, University of Toronto, Ontario, Canada M5G 1X5
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada M5G 1X5
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Abstract
Enteropathogenic Escherichia coli (EPEC) belongs to a family of related bacterial pathogens, including enterohemorrhagic Escherichia coli (EHEC) O157:H7 and other human and animal diarrheagenic pathogens that form attaching and effacing (A/E) lesions on host epithelial surfaces. Bacterial secreted Esp proteins and a type III secretion system are conserved among these pathogens and trigger host cell signal transduction pathways and cytoskeletal rearrangements, and mediate intimate bacterial adherence to epithelial cell surfaces in vitro. However, their role in pathogenesis is still unclear. To investigate the role of Esp proteins in disease, mutations in espA and espB were constructed in rabbit EPEC serotype O103 and infection characteristics were compared to that of the wild-type strain using histology, scanning and transmission electron microscopy, and confocal laser scanning microscopy in a weaned rabbit infection model. The virulence of EspA and EspB mutant strains was severely attenuated. Additionally, neither mutant strain formed A/E lesions, nor did either one cause cytoskeletal actin rearrangements beneath the attached bacteria in the rabbit intestine. Collectively, this study shows for the first time that the type III secreted proteins EspA and EspB are needed to form A/E lesions in vivo and are indeed virulence factors. It also confirms the role of A/E lesions in disease processes.
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Affiliation(s)
- A Abe
- Biotechnology Laboratory, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3
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