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Singh V, Rai R, Mathew BJ, Chourasia R, Singh AK, Kumar A, Chaurasiya SK. Phospholipase C: underrated players in microbial infections. Front Cell Infect Microbiol 2023; 13:1089374. [PMID: 37139494 PMCID: PMC10149971 DOI: 10.3389/fcimb.2023.1089374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 03/21/2023] [Indexed: 05/05/2023] Open
Abstract
During bacterial infections, one or more virulence factors are required to support the survival, growth, and colonization of the pathogen within the host, leading to the symptomatic characteristic of the disease. The outcome of bacterial infections is determined by several factors from both host as well as pathogen origin. Proteins and enzymes involved in cellular signaling are important players in determining the outcome of host-pathogen interactions. phospholipase C (PLCs) participate in cellular signaling and regulation by virtue of their ability to hydrolyze membrane phospholipids into di-acyl-glycerol (DAG) and inositol triphosphate (IP3), which further causes the activation of other signaling pathways involved in various processes, including immune response. A total of 13 PLC isoforms are known so far, differing in their structure, regulation, and tissue-specific distribution. Different PLC isoforms have been implicated in various diseases, including cancer and infectious diseases; however, their roles in infectious diseases are not clearly understood. Many studies have suggested the prominent roles of both host and pathogen-derived PLCs during infections. PLCs have also been shown to contribute towards disease pathogenesis and the onset of disease symptoms. In this review, we have discussed the contribution of PLCs as a determinant of the outcome of host-pathogen interaction and pathogenesis during bacterial infections of human importance.
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Affiliation(s)
- Vinayak Singh
- Molecular Signalling Lab, Department of Biological Science and Engineering, Maulana Azad National Institute of Technology, Bhopal, Madhya Pradesh, India
| | - Rupal Rai
- Molecular Signalling Lab, Department of Biological Science and Engineering, Maulana Azad National Institute of Technology, Bhopal, Madhya Pradesh, India
| | - Bijina J. Mathew
- Molecular Signalling Lab, Department of Biological Science and Engineering, Maulana Azad National Institute of Technology, Bhopal, Madhya Pradesh, India
| | - Rashmi Chourasia
- Department of Chemistry, IES University, Bhopal, Madhya Pradesh, India
| | - Anirudh K. Singh
- School of Sciences, SAM Global University, Raisen, Madhya Pradesh, India
| | - Awanish Kumar
- Department of Biotechnology, National Institute of Technology, Raipur, Chhattisgarh, India
| | - Shivendra K. Chaurasiya
- Molecular Signalling Lab, Department of Biological Science and Engineering, Maulana Azad National Institute of Technology, Bhopal, Madhya Pradesh, India
- *Correspondence: Shivendra K. Chaurasiya,
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2
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Zhao X, Guo J, Jia X, Yang Y, Liu L, Nie W, Fang Z. Internalization of Leptospira interrogans via diverse endocytosis mechanisms in human macrophages and vascular endothelial cells. PLoS Negl Trop Dis 2022; 16:e0010778. [PMID: 36137081 PMCID: PMC9531806 DOI: 10.1371/journal.pntd.0010778] [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: 01/07/2022] [Revised: 10/04/2022] [Accepted: 08/31/2022] [Indexed: 11/18/2022] Open
Abstract
Leptospirosis, one of the leading global causes of morbidity and mortality, is an emerging public health problem, particularly in large urban centers of developing countries. Leptospirosis results from infection with an organism belonging to the Leptospira genus L. interrogans. The extensive invasive ability has previously been documented, however a mechanism that describes how the organism is internalized by human macrophages and transmigrates through human blood vessel remains poorly understood. In the present study, we utilized a human macrophage and vascular endothelial cell line to study the diverse invasive mechanisms by which L. interrogans infections occur. We found that THP-1 and HUVEC had a diverse expression of cell receptors and L. interrogans entered THP-1 and HUVEC by different pathways. In the macrophage model cell line, ITGB1/FAK-signaling mediated microfilament dependent endocytosis with lysosome fusion, whereas ITGB1/CAV-1/PI3K-signaling mediated microfilament dependent endocytosis and transcytosis without lysosome fusion in the endothelial cell model. Shedding of pathogenic leptospires from HUVEC displayed higher viability than those from THP-1. The monolayer of HUVEC maintained integrity during the infection, while 3D imaging showed that leptospires were transmigrated both intra- and intercellularly. These results indicate that endocytosis of leptospires in human macrophages and human vascular endothelial cells are quite different, macrophages are responsible for eliminating leptospires in the human body during the infection while vascular endothelial cells facilitate dissemination of leptospires from blood vessels into target organs where they cause injury. Leptospirosis is a zoonotic bacterial disease which causes 1.03 million cases and 58,900 deaths each year. Human infections occur when the primary reservoir hosts, such as rodents, contaminate food and water with leptospires. Unlike other bacterial pathogens, leptospires invade the human body through mucosal barriers and enter the bloodstream, which can result in septicemia. Left untreated, leptospirosis can spread into multiple organs and tissues such as lungs, liver and kidneys. Pathological features of this disease include high fever, myalgia, lymphadenectasis, hemorrhaging and jaundice. Human macrophages and vascular endothelial cells play important roles in eliminating and preventing the transmission of this pathogen. We speculated that leptospires could be neutralized in macrophages and subsequently transported by vascular endothelial cells throughout the human body. In this research, the diverse mechanisms of human macrophages and vascular endothelial cells infected by leptospires were explored. Our findings can be used to improve the treatment, prevention, and supervision regarding leptospire transmission and infection.
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Affiliation(s)
- Xin Zhao
- Institute of Health Quarantine, Chinese Academy of Inspection and Quarantine, Beijing, China
- * E-mail: (XZ); (ZF)
| | - Jun Guo
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Food Quality and Health of Tianjin, Tianjin University of Science & Technology, Tianjin, China
| | - Xiaoyuan Jia
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Yaling Yang
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Food Quality and Health of Tianjin, Tianjin University of Science & Technology, Tianjin, China
| | - Lijuan Liu
- Institute of Health Quarantine, Chinese Academy of Inspection and Quarantine, Beijing, China
| | - Weizhong Nie
- Department of health quarantine, Qinhuangdao Customs District, Qinhuangdao, China
| | - Zhiqiang Fang
- Institute of Health Quarantine, Chinese Academy of Inspection and Quarantine, Beijing, China
- * E-mail: (XZ); (ZF)
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3
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Paroha R, Chourasia R, Rai R, Kumar A, Vyas AK, Chaurasiya SK, Singh AK. Host phospholipase C‐γ1 impairs phagocytosis and killing of mycobacteria by J774A.1 murine macrophages. Microbiol Immunol 2020; 64:694-702. [DOI: 10.1111/1348-0421.12839] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 08/13/2020] [Accepted: 08/18/2020] [Indexed: 12/11/2022]
Affiliation(s)
- Ruchi Paroha
- Department of Microbiology, School of Biological Sciences Dr Hari Singh Gour University Sagar Madhya Pradesh India
| | - Rashmi Chourasia
- Department of Chemistry Dr Hari Singh Gour University Sagar Madhya Pradesh India
| | - Rupal Rai
- Department of Biological Science and Engineering Maulana Azad National Institute of Technology Bhopal Madhya Pradesh India
| | - Awanish Kumar
- Department of Biotechnology National Institute of Technology Raipur Chhattisgarh India
| | - Ashish K. Vyas
- Department of Microbiology All India Institute of Medical Sciences Bhopal Madhya Pradesh India
| | - Shivendra K. Chaurasiya
- Department of Biological Science and Engineering Maulana Azad National Institute of Technology Bhopal Madhya Pradesh India
| | - Anirudh K. Singh
- Department of Microbiology All India Institute of Medical Sciences Bhopal Madhya Pradesh India
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4
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Wu C, Yang M, Liu R, Hu H, Ji L, Zhang X, Huang S, Wang L. Nicotine Reduces Human Brain Microvascular Endothelial Cell Response to Escherichia coli K1 Infection by Inhibiting Autophagy. Front Cell Infect Microbiol 2020; 10:484. [PMID: 33042863 PMCID: PMC7522313 DOI: 10.3389/fcimb.2020.00484] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 08/04/2020] [Indexed: 01/22/2023] Open
Abstract
Studies have shown that exposure to environmental tobacco smoke can increase the risk of bacterial meningitis, and nicotine is the core component of environmental tobacco smoke. Autophagy is an important way for host cells to eliminate invasive pathogens and resist infection. Escherichia coli K1 strain (E. coli K1) is the most common Gram-negative bacterial pathogen that causes neonatal meningitis. The mechanism of nicotine promoting E. coli K1 to invade human brain microvascular endothelial cells (HBMECs), the main component of the blood–brain barrier, is not clear yet. Our study found that the increase of HBMEC autophagy level during E. coli K1 infection could decrease the survival of intracellular bacteria, while nicotine exposure could inhibit the HBMEC autophagic response of E. coli K1 infection by activating the NF-kappa B and PI3K/Akt/mTOR pathway. We concluded that nicotine could inhibit HBMEC autophagy upon E. coli K1 infection and decrease the scavenging effect on E. coli K1, thus promoting the occurrence and development of neonatal meningitis.
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Affiliation(s)
- Chao Wu
- Department of Histology and Embryology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Mengzhen Yang
- Department of Histology and Embryology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Rui Liu
- Department of Histology and Embryology, School of Basic Medical Sciences, Wuhan University, Wuhan, China.,Department of Human Anatomy, School of Basic Medical Sciences, Hubei University of Medicine, Shiyan, China
| | - Hanyang Hu
- Department of Histology and Embryology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Lulu Ji
- Department of Histology and Embryology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Xiaoli Zhang
- Department of Ultrasound Imaging, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Shenghe Huang
- Kunming Key Laboratory of Children Infection and Immunity, Yunnan Institute of Pediatrics, Kunming Children's Hospital, Kunming, China.,Department of Pediatrics, Children's Hospital Los Angeles, University of Southern California, Los Angeles, CA, United States
| | - Lin Wang
- Department of Histology and Embryology, School of Basic Medical Sciences, Wuhan University, Wuhan, China.,Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan, China
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5
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Virulence Factors of Meningitis-Causing Bacteria: Enabling Brain Entry across the Blood-Brain Barrier. Int J Mol Sci 2019; 20:ijms20215393. [PMID: 31671896 PMCID: PMC6862235 DOI: 10.3390/ijms20215393] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 10/24/2019] [Accepted: 10/25/2019] [Indexed: 12/16/2022] Open
Abstract
Infections of the central nervous system (CNS) are still a major cause of morbidity and mortality worldwide. Traversal of the barriers protecting the brain by pathogens is a prerequisite for the development of meningitis. Bacteria have developed a variety of different strategies to cross these barriers and reach the CNS. To this end, they use a variety of different virulence factors that enable them to attach to and traverse these barriers. These virulence factors mediate adhesion to and invasion into host cells, intracellular survival, induction of host cell signaling and inflammatory response, and affect barrier function. While some of these mechanisms differ, others are shared by multiple pathogens. Further understanding of these processes, with special emphasis on the difference between the blood-brain barrier and the blood-cerebrospinal fluid barrier, as well as virulence factors used by the pathogens, is still needed.
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6
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Li Y, Li KX, Hu WL, Ojcius DM, Fang JQ, Li SJ, Lin X, Yan J. Endocytic recycling and vesicular transport systems mediate transcytosis of Leptospira interrogans across cell monolayer. eLife 2019; 8:44594. [PMID: 31012847 PMCID: PMC6513555 DOI: 10.7554/elife.44594] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 04/18/2019] [Indexed: 12/18/2022] Open
Abstract
Many bacterial pathogens can cause septicemia and spread from the bloodstream into internal organs. During leptospirosis, individuals are infected by contact with Leptospira-containing animal urine-contaminated water. The spirochetes invade internal organs after septicemia to cause disease aggravation, but the mechanism of leptospiral excretion and spreading remains unknown. Here, we demonstrated that Leptospira interrogans entered human/mouse endothelial and epithelial cells and fibroblasts by caveolae/integrin-β1-PI3K/FAK-mediated microfilament-dependent endocytosis to form Leptospira (Lep)-vesicles that did not fuse with lysosomes. Lep-vesicles recruited Rab5/Rab11 and Sec/Exo-SNARE proteins in endocytic recycling and vesicular transport systems for intracellular transport and release by SNARE-complex/FAK-mediated microfilament/microtubule-dependent exocytosis. Both intracellular leptospires and infected cells maintained their viability. Leptospiral propagation was only observed in mouse fibroblasts. Our study revealed that L. interrogans utilizes endocytic recycling and vesicular transport systems for transcytosis across endothelial or epithelial barrier in blood vessels or renal tubules, which contributes to spreading in vivo and transmission of leptospirosis.
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Affiliation(s)
- Yang Li
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University School of Medicine, Hangzhou, China.,Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, China.,Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Kai-Xuan Li
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, China.,Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Wei-Lin Hu
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University School of Medicine, Hangzhou, China.,Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, China.,Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - David M Ojcius
- Department of Biomedical Sciences, Arthur Dugoni School of Dentistry, University of the Pacific, San Francisco, United States
| | - Jia-Qi Fang
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, China.,Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Shi-Jun Li
- Institute of Communicable Disease Prevention and Control, Guizhou Provincial Centre for Disease Control and Prevention, Guiyang, China
| | - Xu'ai Lin
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University School of Medicine, Hangzhou, China.,Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, China.,Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jie Yan
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University School of Medicine, Hangzhou, China.,Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, China.,Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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7
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Huang SH, Chi F, Peng L, Bo T, Zhang B, Liu LQ, Wu X, Mor-Vaknin N, Markovitz DM, Cao H, Zhou YH. Vimentin, a Novel NF-κB Regulator, Is Required for Meningitic Escherichia coli K1-Induced Pathogen Invasion and PMN Transmigration across the Blood-Brain Barrier. PLoS One 2016; 11:e0162641. [PMID: 27657497 PMCID: PMC5033352 DOI: 10.1371/journal.pone.0162641] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 08/25/2016] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND NF-κB activation, pathogen invasion, polymorphonuclear leukocytes (PMN) transmigration (PMNT) across the blood-brain barrier (BBB) are the pathogenic triad hallmark features of bacterial meningitis, but the mechanisms underlying these events remain largely unknown. Vimentin, which is a novel NF-κB regulator, is the primary receptor for the major Escherichia coli K1 virulence factor IbeA that contributes to the pathogenesis of neonatal bacterial sepsis and meningitis (NSM). We have previously shown that IbeA-induced NF-κB signaling through its primary receptor vimentin as well as its co-receptor PTB-associated splicing factor (PSF) is required for pathogen penetration and leukocyte transmigration across the BBB. This is the first in vivo study to demonstrate how vimentin and related factors contributed to the pathogenic triad of bacterial meningitis. METHODOLOGY/PRINCIPAL FINDINGS The role of vimentin in IbeA+ E. coli K1-induced NF-κB activation, pathogen invasion, leukocyte transmigration across the BBB has now been demonstrated by using vimentin knockout (KO) mice. In the in vivo studies presented here, IbeA-induced NF-κB activation, E. coli K1 invasion and polymorphonuclear neutrophil (PMN) transmigration across the BBB were significantly reduced in Vim-/- mice. Decreased neuronal injury in the hippocampal dentate gyrus was observed in Vim-/- mice with meningitis. The major inflammatory regulator α7 nAChR and several signaling molecules contributing to NF-κB activation (p65 and p-CamKII) were significantly reduced in the brain tissues of the Vim-/- mice with E. coli meningitis. Furthermore, Vim KO resulted in significant reduction in neuronal injury and in α7 nAChR-mediated calcium signaling. CONCLUSION/SIGNIFICANCE Vimentin, a novel NF-κB regulator, plays a detrimental role in the host defense against meningitic infection by modulating the NF-κB signaling pathway to increase pathogen invasion, PMN recruitment, BBB permeability and neuronal inflammation. Our findings provide the first evidence for Vim-dependent mechanisms underlying the pathogenic triad of bacterial meningitis.
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Affiliation(s)
- Sheng-He Huang
- Hubei Bioinformatics and Molecular Imaging Key Laboratory, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
- Saban Research Institute of Childrens Hospital Los Angeles, Department of Pediatrics, University of Southern California, Los Angeles, California, United States of America
- Department of Microbiology, School of Public Health and Tropocal Medicine, Southern Medical University, Guangzhou 510515, China
- * E-mail: (YHZ); (SHH)
| | - Feng Chi
- Saban Research Institute of Childrens Hospital Los Angeles, Department of Pediatrics, University of Southern California, Los Angeles, California, United States of America
- Department of Pathology, Southern California Research Center for ALPD and Cirrhosis, the Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Liang Peng
- Saban Research Institute of Childrens Hospital Los Angeles, Department of Pediatrics, University of Southern California, Los Angeles, California, United States of America
- Department of Clinic Laboratory, the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260, China
| | - Tao Bo
- Saban Research Institute of Childrens Hospital Los Angeles, Department of Pediatrics, University of Southern California, Los Angeles, California, United States of America
- Department of Pediatrics, the Second Xiangya Hospital, Central South University, Changsha, China
| | - Bao Zhang
- Saban Research Institute of Childrens Hospital Los Angeles, Department of Pediatrics, University of Southern California, Los Angeles, California, United States of America
- Department of Microbiology, School of Public Health and Tropocal Medicine, Southern Medical University, Guangzhou 510515, China
| | - Li-Qun Liu
- Saban Research Institute of Childrens Hospital Los Angeles, Department of Pediatrics, University of Southern California, Los Angeles, California, United States of America
- Department of Pediatrics, the Second Xiangya Hospital, Central South University, Changsha, China
| | - Xuedong Wu
- Department of Pediatrics, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Nirit Mor-Vaknin
- Department of Internal Medicine, Division of Infectious Diseases, 5220 MSRB III, 1150 West Medical Center Drive, University of Michigan, Ann Arbor, MI, United States of America
| | - David M. Markovitz
- Department of Internal Medicine, Division of Infectious Diseases, 5220 MSRB III, 1150 West Medical Center Drive, University of Michigan, Ann Arbor, MI, United States of America
| | - Hong Cao
- Department of Microbiology, School of Public Health and Tropocal Medicine, Southern Medical University, Guangzhou 510515, China
| | - Yan-Hong Zhou
- Hubei Bioinformatics and Molecular Imaging Key Laboratory, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
- * E-mail: (YHZ); (SHH)
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8
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Doran KS, Fulde M, Gratz N, Kim BJ, Nau R, Prasadarao N, Schubert-Unkmeir A, Tuomanen EI, Valentin-Weigand P. Host-pathogen interactions in bacterial meningitis. Acta Neuropathol 2016; 131:185-209. [PMID: 26744349 PMCID: PMC4713723 DOI: 10.1007/s00401-015-1531-z] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 12/21/2015] [Accepted: 12/22/2015] [Indexed: 12/26/2022]
Abstract
Bacterial meningitis is a devastating disease occurring worldwide with up to half of the survivors left with permanent neurological sequelae. Due to intrinsic properties of the meningeal pathogens and the host responses they induce, infection can cause relatively specific lesions and clinical syndromes that result from interference with the function of the affected nervous system tissue. Pathogenesis is based on complex host–pathogen interactions, some of which are specific for certain bacteria, whereas others are shared among different pathogens. In this review, we summarize the recent progress made in understanding the molecular and cellular events involved in these interactions. We focus on selected major pathogens, Streptococcus pneumonia, S. agalactiae (Group B Streptococcus), Neisseria meningitidis, and Escherichia coli K1, and also include a neglected zoonotic pathogen, Streptococcus suis. These neuroinvasive pathogens represent common themes of host–pathogen interactions, such as colonization and invasion of mucosal barriers, survival in the blood stream, entry into the central nervous system by translocation of the blood–brain and blood–cerebrospinal fluid barrier, and induction of meningeal inflammation, affecting pia mater, the arachnoid and subarachnoid spaces.
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9
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Si Shen Wan Regulates Phospholipase Cγ-1 and PI3K/Akt Signal in Colonic Mucosa from Rats with Colitis. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2015; 2015:392405. [PMID: 26273312 PMCID: PMC4530235 DOI: 10.1155/2015/392405] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 01/29/2015] [Accepted: 02/02/2015] [Indexed: 11/18/2022]
Abstract
The present study explored the feasible pathway of Si Shen Wan (SSW) in inhibiting apoptosis of intestinal epithelial cells (IECs) by observing activation of phospholipase Cγ-1 (PLC-γ1) and PI3K/Akt signal in colonic mucosa from rats with colitis. Experimental colitis was induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS) in the Sprague-Dawley rats. After SSW was administrated for 7 days after TNBS infusion, western blot showed an increment in levels of PI3K, p-Akt, and IL-23 and a decrement in levels of PLC-γ1 and HSP70 in colonic mucosal injury induced by TNBS. Meanwhile, assessments by ELISA revealed an increment in concentrations of IL-2, IL-6, and IL-17 and a reduction in level of TGF-β after TNBS challenge. Impressively, treatment with SSW for 7 days significantly attenuated the expressions of PI3K and p-Akt and the secretion of IL-2, IL-6, IL-17, and IL-23 and promoted the activation of PLC-γ1, HSP70, and TGF-β. Our previous studies had demonstrated that SSW restored colonic mucosal ulcers by inhibiting apoptosis of IECs. The present study demonstrated that the effect of SSW on inhibiting apoptosis of IECs was realized probably by activation of PLC-γ1 and suppression of PI3K/Akt signal pathway.
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10
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Krishnan S, Prasadarao NV. Identification of minimum carbohydrate moiety in N-glycosylation sites of brain endothelial cell glycoprotein 96 for interaction with Escherichia coli K1 outer membrane protein A. Microbes Infect 2014; 16:540-52. [PMID: 24932957 PMCID: PMC4123687 DOI: 10.1016/j.micinf.2014.06.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 05/31/2014] [Accepted: 06/02/2014] [Indexed: 12/19/2022]
Abstract
Bacterial meningitis is a serious central nervous system infection and Escherichia coli K1 (E. coli K1) is one of the leading etiological agents that cause meningitis in neonates. Outer membrane protein A (OmpA) of E. coli K1 is a major virulence factor in the pathogenesis of meningitis, and interacts with human brain microvascular endothelial cells (HBMEC) to cross the blood-brain barrier. Using site-directed mutagenesis, we demonstrate that two N-glycosylation sites (NG1 and NG2) in the extracellular domain of OmpA receptor, Ecgp96 are critical for bacterial binding to HBMEC. E. coli K1 invasion assays using CHO-Lec1 cells that express truncated N-glycans, and sequential digestion of HBMEC surface N-glycans using specific glycosidases showed that GlcNAc1-4GlcNAc epitopes are sufficient for OmpA interaction with HBMEC. Lack of NG1 and NG2 sites in Ecgp96 inhibits E. coli K1 OmpA induced F-actin polymerization, phosphorylation of protein kinase C-α, and disruption of transendothelial electrical resistance required for efficient invasion of E. coli K1 in HBMEC. Furthermore, the microvessels of cortex and hippocampus of the brain sections of E. coli K1 infected mice showed increased expression of glycosylated Ecgp96. Therefore, the interface of OmpA and GlcNAc1-4GlcNAc epitope interaction would be a target for preventative strategies against E. coli K1 meningitis.
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Affiliation(s)
- Subramanian Krishnan
- Division of Infectious Diseases and Department of Pediatrics, Children's Hospital Los Angeles, 4650 Sunset Blvd., Los Angeles, CA 90027, USA
| | - Nemani V Prasadarao
- Division of Infectious Diseases and Department of Pediatrics, Children's Hospital Los Angeles, 4650 Sunset Blvd., Los Angeles, CA 90027, USA; Department of Surgery, Children's Hospital Los Angeles and University of Southern California, 4650 Sunset Blvd., Los Angeles, CA 90027, USA.
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11
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Edwards MW, Aultman JA, Harber G, Bhatt JM, Sztul E, Xu Q, Zhang P, Michalek SM, Katz J. Role of mTOR downstream effector signaling molecules in Francisella tularensis internalization by murine macrophages. PLoS One 2013; 8:e83226. [PMID: 24312679 PMCID: PMC3849438 DOI: 10.1371/journal.pone.0083226] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 11/11/2013] [Indexed: 02/03/2023] Open
Abstract
Francisella tularensis is an infectious, gram-negative, intracellular microorganism, and the cause of tularemia. Invasion of host cells by intracellular pathogens like Francisella is initiated by their interaction with different host cell membrane receptors and the rapid phosphorylation of different downstream signaling molecules. PI3K and Syk have been shown to be involved in F. tularensis host cell entry, and both of these signaling molecules are associated with the master regulator serine/threonine kinase mTOR; yet the involvement of mTOR in F. tularensis invasion of host cells has not been assessed. Here, we report that infection of macrophages with F. tularensis triggers the phosphorylation of mTOR downstream effector molecules, and that signaling via TLR2 is necessary for these events. Inhibition of mTOR or of PI3K, ERK, or p38, but not Akt signaling, downregulates the levels of phosphorylation of mTOR downstream targets, and significantly reduces the number of F. tularensis cells invading macrophages. Moreover, while phosphorylation of mTOR downstream effectors occurs via the PI3K pathway, it also involves PLCγ1 and Ca(2+) signaling. Furthermore, abrogation of PLC or Ca(2+) signaling revealed their important role in the ability of F. tularensis to invade host cells. Together, these findings suggest that F. tularensis invasion of primary macrophages utilize a myriad of host signaling pathways to ensure effective cell entry.
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Affiliation(s)
- Michael W. Edwards
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - James A. Aultman
- Department of Pediatric Dentistry, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Gregory Harber
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Jay M. Bhatt
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Elizabeth Sztul
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Qingan Xu
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Ping Zhang
- Department of Pediatric Dentistry, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Suzanne M. Michalek
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Jannet Katz
- Department of Pediatric Dentistry, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
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12
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Krishnan S, Chen S, Turcatel G, Arditi M, Prasadarao NV. Regulation of Toll-like receptor 2 interaction with Ecgp96 controls Escherichia coli K1 invasion of brain endothelial cells. Cell Microbiol 2012; 15:63-81. [PMID: 22963587 DOI: 10.1111/cmi.12026] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 08/16/2012] [Accepted: 09/04/2012] [Indexed: 01/19/2023]
Abstract
The interaction of outer membrane protein A (OmpA) with its receptor, Ecgp96 (a homologue of Hsp90β), is critical for the pathogenesis of Escherichia coli K1 meningitis. Since Hsp90 chaperones Toll-like receptors (TLRs), we examined the role of TLRs in E. coli K1 infection. Herein, we show that newborn TLR2(-/-) mice are resistant to E. coli K1 meningitis, while TLR4(-/-) mice succumb to infection sooner. In vitro, OmpA+ E. coli infection selectively upregulates Ecgp96 and TLR2 in human brain microvascular endothelial cells (HBMEC), whereas OmpA- E. coli upregulates TLR4 in these cells. Furthermore, infection with OmpA+ E. coli causes Ecgp96 and TLR2 translocate to the plasma membrane of HBMEC as a complex. Immunoprecipitation studies of the plasma membrane fractions from infected HBMEC reveal that the C termini of Ecgp96 and TLR2 are critical for OmpA+ E. coli invasion. Knockdown of TLR2 using siRNA results in inefficient membrane translocation of Ecgp96 and significantly reduces invasion. In addition, the interaction of Ecgp96 andTLR2 induces a bipartite signal, one from Ecgp96 through PKC-α while the other from TLR2 through MyD88, ERK1/2 and NF-κB. This bipartite signal ultimately culminates in the efficient production of NO, which in turn promotes E. coli K1 invasion of HBMEC.
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Affiliation(s)
- Subramanian Krishnan
- Division of Infectious Diseases, Children's Hospital Los Angeles, Los Angeles, CA 90027, USA
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13
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Smani Y, Docobo-Pérez F, López-Rojas R, Domínguez-Herrera J, Ibáñez-Martínez J, Pachón J. Platelet-activating factor receptor initiates contact of Acinetobacter baumannii expressing phosphorylcholine with host cells. J Biol Chem 2012; 287:26901-10. [PMID: 22689572 DOI: 10.1074/jbc.m112.344556] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Adhesion is an initial and important step in Acinetobacter baumannii causing infections. However, the exact molecular mechanism of such a step between A. baumannii and the host cells remains unclear. Here, we demonstrated that the phosphorylcholine (ChoP)-containing outer membrane protein of A. baumannii binds to A549 cells through platelet-activating factor receptor (PAFR), resulting in activation of G protein and intracellular calcium. Upon A. baumannii expressing ChoP binding to PAFR, clathrin and β-arrestins, proteins involved in the direction of the vacuolar movement, are activated during invasion of A. baumannii. PAFR antagonism restricts the dissemination of A. baumannii in the pneumonia model. These results define a role for PAFR in A. baumannii interaction with host cells and suggest a mechanism for the entry of A. baumannii into the cytoplasm of host cells.
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Affiliation(s)
- Younes Smani
- Clinic Unit of Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville, 41013 Seville, Spain.
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14
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Mechanisms of Candida albicans trafficking to the brain. PLoS Pathog 2011; 7:e1002305. [PMID: 21998592 PMCID: PMC3188548 DOI: 10.1371/journal.ppat.1002305] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Accepted: 08/24/2011] [Indexed: 01/15/2023] Open
Abstract
During hematogenously disseminated disease, Candida albicans infects most organs, including the brain. We discovered that a C. albicans vps51Δ/Δ mutant had significantly increased tropism for the brain in the mouse model of disseminated disease. To investigate the mechanisms of this enhanced trafficking to the brain, we studied the interactions of wild-type C. albicans and the vps51Δ/Δ mutant with brain microvascular endothelial cells in vitro. These studies revealed that C. albicans invasion of brain endothelial cells is mediated by the fungal invasins, Als3 and Ssa1. Als3 binds to the gp96 heat shock protein, which is expressed on the surface of brain endothelial cells, but not human umbilical vein endothelial cells, whereas Ssa1 binds to a brain endothelial cell receptor other than gp96. The vps51Δ/Δ mutant has increased surface expression of Als3, which is a major cause of the increased capacity of this mutant to both invade brain endothelial cells in vitro and traffic to the brain in mice. Therefore, during disseminated disease, C. albicans traffics to and infects the brain by binding to gp96, a unique receptor that is expressed specifically on the surface of brain endothelial cells. During hematogenously disseminated infection, the fungus Candida albicans is carried by the bloodstream to virtually all organs in the body, including the brain. C. albicans infection of the brain is a significant problem in premature infants with disseminated candidiasis. To infect the brain, C. albicans must adhere to and invade the endothelial cells that line cerebral blood vessels. These endothelial cells express unique proteins on their surface that are not expressed by endothelial cells of other vascular beds. Here, we show that C. albicans infects the brain by binding to gp96, a heat shock protein that is uniquely expressed on the surface of brain endothelial cells. Gp96 is bound by the C. albicans Als3 invasin, which induces the uptake of this organism by brain endothelial cells. The C. albicans Ssa1 invasin also mediates fungal uptake by brain endothelial cells, but does so by binding to a receptor other than gp96. Thus, during hematogenously disseminated infection, C. albicans traffics to and infects the brain by binding to gp96, a receptor that is expressed specifically on the surface of brain endothelial cells.
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15
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Chi F, Wang L, Zheng X, Wu CH, Jong A, Sheard MA, Shi W, Huang SH. Meningitic Escherichia coli K1 penetration and neutrophil transmigration across the blood-brain barrier are modulated by alpha7 nicotinic receptor. PLoS One 2011; 6:e25016. [PMID: 21966399 PMCID: PMC3178609 DOI: 10.1371/journal.pone.0025016] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Accepted: 08/22/2011] [Indexed: 11/19/2022] Open
Abstract
Alpha7 nicotinic acetylcholine receptor (nAChR), an essential regulator of inflammation, is abundantly expressed in hippocampal neurons, which are vulnerable to bacterial meningitis. However, it is unknown whether α7 nAChR contributes to the regulation of these events. In this report, an aggravating role of α7 nAChR in host defense against meningitic E. coli infection was demonstrated by using α7-deficient (α7(-/-)) mouse brain microvascular endothelial cells (BMEC) and animal model systems. As shown in our in vitro and in vivo studies, E. coli K1 invasion and polymorphonuclear neutrophil (PMN) transmigration across the blood-brain barrier (BBB) were significantly reduced in α7(-/-) BMEC and α7(-/-) mice. Stimulation by nicotine was abolished in the α7(-/-) cells and animals. The same blocking effect was achieved by methyllycaconitine (α7 antagonist). The tight junction molecules occludin and ZO-1 were significantly reduced in the brain cortex of wildtype mice infected with E. coli and treated with nicotine, compared to α7(-/-) cells and animals. Decreased neuronal injury in the hippocampal dentate gyrus was observed in α7(-/-) mice with meningitis. Proinflammatory cytokines (IL-1β, IL-6, TNFα, MCP-1, MIP-1alpha, and RANTES) and adhesion molecules (CD44 and ICAM-1) were significantly reduced in the cerebrospinal fluids of the α7(-/-) mice with E. coli meningitis. Furthermore, α7 nAChR is the major calcium channel for nicotine- and E. coli K1-increased intracellular calcium concentrations of mouse BMEC. Taken together, our data suggest that α7 nAChR plays a detrimental role in the host defense against meningitic infection by modulation of pathogen invasion, PMN recruitment, calcium signaling and neuronal inflammation.
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Affiliation(s)
- Feng Chi
- Department of Pediatrics, Saban Research Institute, University of Southern California, Childrens Hospital Los Angeles, Los Angeles, California, United States of America
| | - Lin Wang
- Department of Pediatrics, Saban Research Institute, University of Southern California, Childrens Hospital Los Angeles, Los Angeles, California, United States of America
- Department of Histology and Embryology, School of Basic Medical Science, Wuhan University, Wuhan, China
| | - Xueye Zheng
- Department of Pediatrics, Saban Research Institute, University of Southern California, Childrens Hospital Los Angeles, Los Angeles, California, United States of America
| | - Chun-Hua Wu
- Department of Pediatrics, Saban Research Institute, University of Southern California, Childrens Hospital Los Angeles, Los Angeles, California, United States of America
| | - Ambrose Jong
- Department of Pediatrics, Saban Research Institute, University of Southern California, Childrens Hospital Los Angeles, Los Angeles, California, United States of America
| | - Michael A. Sheard
- Department of Pediatrics, Saban Research Institute, University of Southern California, Childrens Hospital Los Angeles, Los Angeles, California, United States of America
| | - Wei Shi
- Department of Pediatrics, Saban Research Institute, University of Southern California, Childrens Hospital Los Angeles, Los Angeles, California, United States of America
| | - Sheng-He Huang
- Department of Pediatrics, Saban Research Institute, University of Southern California, Childrens Hospital Los Angeles, Los Angeles, California, United States of America
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16
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Kukkonen JP. A ménage à trois made in heaven: G-protein-coupled receptors, lipids and TRP channels. Cell Calcium 2011; 50:9-26. [DOI: 10.1016/j.ceca.2011.04.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 04/21/2011] [Accepted: 04/22/2011] [Indexed: 12/15/2022]
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17
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Ko Y, Cho NH, Cho BA, Kim IS, Choi MS. Involvement of Ca2+ signaling in intracellular invasion of non-phagocytic host cells by Orientia tsutsugamushi. Microb Pathog 2011; 50:326-30. [DOI: 10.1016/j.micpath.2011.02.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 02/15/2011] [Accepted: 02/21/2011] [Indexed: 10/18/2022]
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18
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Faropoulos K, Chroni E, Assimakopoulos SF, Mavrakis A, Stamatopoulou V, Toumpeki C, Drainas D, Grintzalis K, Papapostolou I, Georgiou CD, Konstantinou D. Altered occludin expression in brain capillaries induced by obstructive jaundice in rats. Brain Res 2010; 1325:121-7. [PMID: 20170644 DOI: 10.1016/j.brainres.2010.02.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Revised: 01/30/2010] [Accepted: 02/04/2010] [Indexed: 11/18/2022]
Abstract
The development of increased oxidative stress in the context of obstructive cholestasis has been proven in various rats' organs including the brain. The present study aimed to detect alterations of tight junction-associated occludin in rat brain capillaries after bile duct ligation (BDL). In experiment 1, occludin expression was evaluated by Western blot analysis in 5 animals 10 days after BDL and compared with 5 sham-operated ones. In experiment 2, groups of 9 animals each were used to assess occludin levels on the 1st, 5th, and 10th days after BDL and to associate these measurements with the in vivo superoxide radical production measured by means of an ultrasensitive fluorescent assay. The results indicated that occludin expression in BDL animals, as opposed to sham-operated, was significantly reduced at every time point studied, being lowest in the rats remaining on BDL condition for 10 days. Moreover, it was demonstrated that the time-dependent downregulation of occludin expression in the brain endothelial was significantly correlated with the time-dependent increase of brain superoxide radical level, implying a relationship between these two abnormalities. In conclusion, the evidence presented herein suggests the implication of occludin and, therefore, of blood-brain barrier in the pathophysiology of extrahepatic cholestasis.
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Affiliation(s)
- Konstantinos Faropoulos
- Department of Neurosurgery, School of Medicine, Division of Genetics, Cell and Developmental Biology, University of Patras, Patras, Greece
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19
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Liu W, Zhao WD, Yan JC, Ren ZY, Fang WG, Zhu L, Shang DS, Chen YH. Involvement of Src tyrosine kinase in Escherichia coli invasion of human brain microvascular endothelial cells. FEBS Lett 2010; 584:27-32. [PMID: 19903481 DOI: 10.1016/j.febslet.2009.10.090] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2009] [Revised: 10/24/2009] [Accepted: 10/30/2009] [Indexed: 12/31/2022]
Abstract
Invasion of brain microvascular endothelial cells is a prerequisite for successful crossing of the blood-brain barrier by Escherichia coli (E. coli), but the underlying mechanism remains unclear. Here we showed activation of Src tyrosine kinase in E. coli K1 invasion of human brain microvascular endothelial cells (HBMEC). E. coli invasion of HBMEC and the E. coli-induced rearrangement of actin filaments were blocked by Src inhibitors. Overexpression of dominant-negative Src in HBMEC significantly attenuated E. coli invasion and the concomitant actin filaments rearrangement. Furthermore, E. coli K1-triggered phosphatidylinositol 3-kinase (PI3K) activation in HBMEC was effectively blocked by Src inhibitors and dominant-negative Src. These results demonstrated the involvement of Src and its interaction with PI3K in E. coli K1 invasion of HBMEC.
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Affiliation(s)
- Wei Liu
- Department of Developmental Biology, Key Laboratory of Cell Biology, Ministry of Public Health, Heping Distric, Shenyang, China
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20
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Mittal R, Prasadarao NV. Nitric oxide/cGMP signalling induces Escherichia coli K1 receptor expression and modulates the permeability in human brain endothelial cell monolayers during invasion. Cell Microbiol 2009; 12:67-83. [PMID: 19732056 DOI: 10.1111/j.1462-5822.2009.01379.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Escherichia coli K1 invasion of human brain microvascular endothelial cells (HBMEC) mediated by outer membrane protein A (OmpA) results in the leakage of HBMEC monolayers. Despite the influence of nitric oxide (NO) in endothelial cell tight junction integrity, its role in E. coli-induced HBMEC monolayer permeability is poorly defined. Here, we demonstrate that E. coli invasion of HBMEC stimulates NO production by increasing the inducible nitric oxide synthase (iNOS) expression. Exposure to NO-producing agents enhanced the invasion of OmpA(+)E. coli and thereby increased the permeability of HBMEC. OmpA(+)E. coli-induced NO production lead to increased generation of cGMP and triggered the expression of OmpA receptor, Ec-gp96 in HBMEC. Pre-treatment of HBMEC with iNOS inhibitors or by introducing siRNA to iNOS, but not to eNOS or cGMP inhibitors abrogated the E. coli-induced expression of Ec-gp96. Overexpression of the C-terminal truncated Ec-gp96 in HBMEC prevented NO production and its downstream effector, cGMP generation and consequently, the invasion of OmpA(+)E. coli. NO/cGMP production also activates PKC-alpha, which is previously shown to be involved in HBMEC monolayer leakage. These results indicate that NO/cGMP signalling pathway plays a novel role in OmpA(+)E. coli invasion of HBMEC by enhancing the surface expression of Ec-gp96.
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Affiliation(s)
- Rahul Mittal
- The Saban Research Institute, Children's Hospital Los Angeles, CA 90027, USA
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21
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Uliczka F, Kornprobst T, Eitel J, Schneider D, Dersch P. Cell invasion of Yersinia pseudotuberculosis by invasin and YadA requires protein kinase C, phospholipase C-gamma1 and Akt kinase. Cell Microbiol 2009; 11:1782-801. [PMID: 19681907 DOI: 10.1111/j.1462-5822.2009.01371.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The outer membrane proteins YadA and invasin of Yersinia pseudotuberculosis promote invasion into mammalian cells through beta(1)-integrins and trigger the production of interleukin (IL)-8. FAK, c-Src and the PI3 kinase were previously found to be important for both YadA- and invasin-promoted uptake. Here, we demonstrate that two different downstream effectors of PI3 kinase, Akt and phospholipase Cgamma1 are required for efficient cell invasion. Inhibition of Akt or phospholipase C-gamma (PLC-gamma)1 by pharmaceutical agents as well as reduced expression of the isoforms Akt1 and Akt2, and of PLC-gamma1 by RNA interference decreased entry of YadA- and Inv-expressing bacteria significantly. In addition, we report that the conventional protein kinases C (PKC)alpha and -beta, positioned downstream of PLC-gamma1, are activated upon Inv- or YadA-promoted cell entry. They colocalize with intracellular bacteria and their depletion by siRNA treatment also resulted in a strong reduction of cell entry. In contrast, neither Akt nor PLC-gamma1, and the PKCs are essential for YadA- and Inv-mediated IL-8 synthesis and release. We conclude that YadA and invasin of Y. pseudotuberculosis both trigger similar signal transduction pathways during integrin-mediated phagocytosis into epithelial cells, which lead to the activation of Akt, PLC-gamma1, PKCalpha and -beta downstream of PI3 kinase, separate from the MAPK-dependent pathway that triggers IL-8 production.
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Affiliation(s)
- Frank Uliczka
- Institut für Mikrobiologie, Technische Universität Braunschweig, 38106 Braunschweig, Germany
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22
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Wu D, Peng F, Zhang B, Ingram AJ, Kelly DJ, Gilbert RE, Gao B, Kumar S, Krepinsky JC. EGFR-PLCgamma1 signaling mediates high glucose-induced PKCbeta1-Akt activation and collagen I upregulation in mesangial cells. Am J Physiol Renal Physiol 2009; 297:F822-34. [PMID: 19605547 DOI: 10.1152/ajprenal.00054.2009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Glomerular matrix accumulation is a hallmark of diabetic nephropathy. We have recently shown that epidermal growth factor receptor (EGFR) transactivation mediates high glucose (HG)-induced collagen I upregulation through PI3K-PKCbeta1-Akt signaling in mesangial cells (MC). Phospholipase Cgamma1 (PLCgamma1) interacts with activated growth factor receptors and activates classic PKC isoforms. We thus studied its role in HG-induced collagen I upregulation in MC. Primary rat MC were treated with HG (30 mM) or mannitol as osmotic control. Protein kinase activation was assessed by Western blotting and collagen I upregulation by Northern blotting. Diabetes was induced in rats by streptozotocin. HG treatment for 1 h led to PLCgamma1 membrane translocation and Y783 phosphorylation, both indicative of its activation. Mannitol was without effect. PLCgamma1 Y783 phosphorylation was also seen in cortex and glomeruli of diabetic rats. HG induced a physical association between EGFR and PLCgamma1 as identified by coimmunoprecipitation. PLCgamma1 activation required EGFR kinase activity since it was prevented by the EGFR inhibitor AG1478 or overexpression of kinase-inactive EGFR (K721A). Phosphoinositide-3-OH kinase inhibition also prevented PLCgamma1 activation. HG-induced Akt S473 phosphorylation, effected by PKCbeta1, was inhibited by the PLCgamma inhibitor U73122. PLCgamma1 inhibition or downregulation by small interference RNA also prevented HG-induced collagen I upregulation. Our results indicate that EGFR-PLCgamma1 signaling mediates HG-induced PKCbeta1-Akt activation and subsequent collagen I upregulation in MC. Inhibition of EGFR or PLCgamma1 may provide attractive therapeutic targets for the treatment of diabetic nephropathy.
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Affiliation(s)
- D Wu
- Division of Nephrology, McMaster University, Hamilton, Ontario, Canada
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23
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Chun J, Prince A. Ca2+ signaling in airway epithelial cells facilitates leukocyte recruitment and transepithelial migration. J Leukoc Biol 2009; 86:1135-44. [PMID: 19605699 DOI: 10.1189/jlb.0209072] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
In airway cells, TLR2 stimulation by bacterial products activates Ca2+ fluxes that signal leukocyte recruitment to the lung and facilitates transepithelial migration into the airway lumen. TLR2 is apically displayed on airway cells, where it senses bacterial stimuli. Biochemical and genetic approaches demonstrate that TLR2 ligands stimulate release of Ca2+ from intracellular stores by activating TLR2 phosphorylation by c-Src and recruiting PI3K and PLCgamma to affect Ca2+ release through IP3Rs. This Ca2+ release plays a pivotal role in signaling TLR2-dependent NF-kappaB activation and chemokine expression to recruit PMNs to the lung. In addition, TLR2-initiated Ca2+ release activates Ca2+-dependent proteases, calpains, which cleave the transmembrane proteins occludin and E-cadherin to promote PMN transmigration. This review highlights recent findings that demonstrate a central role for Ca2+ signaling in airway epithelial cells to induce proinflammatory gene transcription and to initiate junctional changes that accommodate transmigration of recruited PMNs.
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Affiliation(s)
- Jarin Chun
- Department of Pharmacology and Pediatrics, College of Physicians & Surgeons, Columbia University, New York, New York 10032, USA
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24
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Maruvada R, Argon Y, Prasadarao NV. Escherichia coli interaction with human brain microvascular endothelial cells induces signal transducer and activator of transcription 3 association with the C-terminal domain of Ec-gp96, the outer membrane protein A receptor for invasion. Cell Microbiol 2008; 10:2326-38. [PMID: 18662321 PMCID: PMC2579944 DOI: 10.1111/j.1462-5822.2008.01214.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Our inability to develop new therapeutic strategies to prevent meningitis due to Escherichia coli K1 is attributed to our incomplete understanding of the pathophysiology of the disease. Previously, we demonstrated that outer membrane protein A of E. coli interacts with a gp96 homologue, Ec-gp96, on human brain microvascular endothelial cells (HBMEC) for invasion. However, signalling events mediated by Ec-gp96 that allow internalization of E. coli are incompletely understood. Here, we demonstrate that signal transducer and activator of transcription 3 (Stat3) activation and its interaction with Ec-gp96 were critical for E. coli invasion. The activated Stat3 was colocalized with Ec-gp96 at the actin condensation sites, and overexpressing a dominant negative (DN) form of Stat3 in HBMEC significantly abrogated the invasion. Furthermore, overexpression of Ec-gp96Delta200, the C-terminal 214-amino-acid truncated Ec-gp96, prevented the invasion of E. coli in HBMEC. In contrast, lack of ATP binding by gp96 did not affect the invasion. Overexpression of DN forms of either phosphatidyl inositol-3 kinase (PI3-kinase) subunit p85 or protein kinase C-alpha (PKC-alpha) had no effect on the activation of Stat3 and its association with Ec-gp96, whereas overexpression of DN-Stat3 abolished the activation of both PI3-kinase and PKC-alpha. Together, our findings identified a novel interaction of Stat3 with Ec-gp96, upstream of PI3-kinase and PKC-alpha activation that is required for the invasion of E. coli into HBMEC.
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Affiliation(s)
- Ravi Maruvada
- Division of Infectious Diseases, The Saban Research Institute, Childrens Hospital Los Angeles
| | - Yair Argon
- Division of Cell Pathology, Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia and University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Nemani V. Prasadarao
- Division of Infectious Diseases, The Saban Research Institute, Childrens Hospital Los Angeles
- Keck School of Medicine, University of Southern California, Los Angeles, CA 90027, USA
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25
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Maffucci T, Falasca M. Phosphoinositide 3-kinase-dependent regulation of phospholipase Cγ. Biochem Soc Trans 2007; 35:229-30. [PMID: 17371245 DOI: 10.1042/bst0350229] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Activation of the enzyme PLC (phospholipase C) leads to the formation of second messengers Ins(1,4,5)P3 and diacylglycerol. RTKs (receptor tyrosine kinases) activate this reaction through PLCγ isoenzymes. It has been shown that PI3K (phosphoinositide 3-kinase) may regulate PLCγ activity through the interaction of PI3K product PtdIns(3,4,5)P3 and the PLCγ PH domain (pleckstrin homology domain). Here, we analyse the potential functional roles of the PI3K/PLC pathway.
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Affiliation(s)
- T Maffucci
- Centre for Cardiovascular Biology and Medicine, Division of Medicine, The Rayne Institute, University College London, London, UK.
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26
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Selvaraj SK, Periandythevar P, Prasadarao NV. Outer membrane protein A of Escherichia coli K1 selectively enhances the expression of intercellular adhesion molecule-1 in brain microvascular endothelial cells. Microbes Infect 2007; 9:547-57. [PMID: 17368067 PMCID: PMC1993839 DOI: 10.1016/j.micinf.2007.01.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Revised: 12/21/2006] [Accepted: 01/18/2007] [Indexed: 01/26/2023]
Abstract
Escherichia coli K1 meningitis is a serious central nervous system disease with unchanged mortality and morbidity rates for last few decades. Intercellular adhesion molecule 1 (ICAM-1) is a cell adhesion molecule involved in leukocyte trafficking toward inflammatory stimuli at the vascular endothelium; however, the effect of E. coli invasion of endothelial cells on the expression of ICAM-1 is not known. We demonstrate here that E. coli K1 invasion of human brain microvascular endothelial cells (HBMEC) selectively up-regulates the expression of ICAM-1, which occurs only in HBMEC invaded by the bacteria. The interaction of outer membrane protein A (OmpA) of E. coli with its receptor, Ecgp, on HBMEC was critical for the up-regulation of ICAM-1 and was depend on PKC-alpha and PI3-kinase signaling. Of note, the E. coli-induced up-regulation of ICAM-1 was not due to the cytokines secreted by HBMEC upon bacterial infection. Activation of NF-kappaB was required for E. coli mediated expression of ICAM-1, which was significantly inhibited by over-expressing the dominant negative forms of PKC-alpha and p85 subunit of PI3-kinase. The increased expression of ICAM-1 also enhanced the binding of THP-1 cells to HBMEC. Taken together, these data suggest that localized increase in ICAM-1 expression in HBMEC invaded by E. coli requires a novel interaction between OmpA and its receptor, Ecgp.
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Affiliation(s)
- Suresh K. Selvaraj
- Division of Infectious Diseases, The Saban Research Institute, Children’s Hospital Los Angeles, Los Angeles, CA 90027, USA
| | - Parameswaran Periandythevar
- Division of Infectious Diseases, The Saban Research Institute, Children’s Hospital Los Angeles, Los Angeles, CA 90027, USA
| | - Nemani V. Prasadarao
- Division of Infectious Diseases, The Saban Research Institute, Children’s Hospital Los Angeles, Los Angeles, CA 90027, USA
- Keck School of Medicine, University of Southern California, Los Angeles, CA 90027, USA
- * Corresponding author. Division of Infectious Diseases, MS #51, The Saban Research Institute, Children’s Hospital Los Angeles, 4650 Sunset Boulevard, Los Angeles, CA 90027, USA. Tel.: +1 323 669 5465; fax: +1 323 660 2661. E-mail address: (N.V. Prasadarao)
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Haorah J, Knipe B, Gorantla S, Zheng J, Persidsky Y. Alcohol-induced blood?brain barrier dysfunction is mediated via inositol 1,4,5-triphosphate receptor (IP3R)-gated intracellular calcium release. J Neurochem 2007; 100:324-36. [PMID: 17241155 DOI: 10.1111/j.1471-4159.2006.04245.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The blood-brain barrier (BBB) formed by brain microvascular endothelial cells (BMVEC), pericytes and astrocytes controls the transport of ions, peptides and leukocytes in and out of the brain. Tight junctions (TJ) composed of TJ proteins (occludin, claudins and zonula occludens) ensure the structural integrity of the BMVEC monolayer. Neuropathologic studies indicated that the BBB was impaired in alcohol abusers; however, the underlying mechanism of BBB dysfunction remains elusive. Using primary human BMVEC, we previously demonstrated that oxidative stress induced by ethanol (EtOH) metabolism in BMVEC activated myosin light chain kinase (MLCK), resulting in the enhanced phosphorylation of either cytoskeletal or TJ proteins, and in BBB impairment. We proposed that EtOH metabolites stimulated inositol 1,4,5-triphosphate receptor (IP(3)R)-operated intracellular calcium (Ca(2+)) release, thereby causing the activation of MLCK in BMVEC. Indeed, treatment of primary human BMVEC with EtOH or its metabolites resulted in the increased expression of IP(3)R protein and IP(3)R-gated intracellular Ca(2+) release. These functional changes paralleled MLCK activation, phosphorylation of cytoskeletal/TJ proteins, loss of BBB integrity, and enhanced leukocyte migration across BMVEC monolayers. Inhibition of either EtOH metabolism or IP(3)R activation prevented BBB impairment. These findings suggest that EtOH metabolites act as signaling molecules for the activation of MLCK via the stimulation of IP(3)R-gated intracellular Ca(2+) release in BMVEC. These putative events can lead to BBB dysfunction in the setting of alcoholism, and to neuro-inflammatory disorders promoting leukocyte migration across the BBB.
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Affiliation(s)
- James Haorah
- Center for Neurovirology and Neurodegenerative Disorders, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska 68198-5215, USA.
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Chun J, Prince A. Activation of Ca2+-dependent signaling by TLR2. THE JOURNAL OF IMMUNOLOGY 2006; 177:1330-7. [PMID: 16818794 DOI: 10.4049/jimmunol.177.2.1330] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Upon contact with airway epithelial cells, bacterial products activate Ca(2+) fluxes that are required for induction of NF-kappaB-dependent gene expression. TLR2 is apically displayed on airway cells, making it a likely transducer linking bacterial stimuli and kinases that affect Ca(2+) release. Using biochemical and genetic approaches, we demonstrate that TLR2 ligands stimulate release of Ca(2+) from intracellular stores by activating TLR2 phosphorylation by c-Src, and recruiting PI3K and phospholipase Cgamma to affect Ca(2+) release through inositol (1,4,5) trisphosphate receptors. In the absence of TLR2, murine macrophages as well as airway cells do not generate Ca(2+) fluxes or induce proinflammatory signaling. Thus, Ca(2+) participates as a second messenger in TLR2-dependent signaling and provides another target to modulate proinflammatory responses to bacterial infection.
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Affiliation(s)
- Jarin Chun
- College of Physicians and Surgeons, Columbia University, 650 West 168th Street, New York, NY 10032, USA
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Muscella A, Storelli C, Marsigliante S. Atypical PKC-zeta and PKC-iota mediate opposing effects on MCF-7 Na+/K+ATPase activity. J Cell Physiol 2005; 205:278-85. [PMID: 15887250 DOI: 10.1002/jcp.20396] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We demonstrated previously that in serum-starved MCF-7 breast cancer cell line, Ang II increased Na+/K+ATPase activity and activated the protein kinase C zeta (PKC-zeta) (Muscella et al., 2002 J Endocrinol 173:315-323; 2003 J Cell Physiol 197:61-68.). The aim of the present study was to investigate the modulation of the activity of the Na+/K+ATPase by PKC-zeta in MCF-7 cells. Here, using serum-starved MCF-7 cells, we have demonstrated that the effect of Ang II on the Na+/K+ATPase activity was inhibited by a synthetic myristoylated peptide with sequences based on the endogenous PKC-zeta pseudosubstrate region (zeta-PS) and by high doses of GF109203X, inhibitor of PKCs. When MCF-7 cells, grown in 10% fetal bovine serum (FBS), were stimulated with Ang II a dose- and time-dependent inhibition of the Na+/K+ATPase activity was obtained. Under this growth condition we found that mRNAs for AT1, AT2, and for Na+/K+ATPase alpha1 and alpha3 subunits were unchanged; besides both the activity of the Na+/K+ATPase and the level of PKC-zeta also were unaffected by the serum. The atypical PKC-iota level (present in very low abundance in serum-starved MCF-7) was increased and Ang II provoked its translocation from the cytosol to plasma membrane. PKC-zeta was localized to the membrane, and upon Ang II treatment its cellular localization did not change. The Ang II-mediated decrease of the Na+/K+ATPase activity was inhibited by high doses of GF109203X but not by zeta-PS, thus indicating that such effect was not due to PKC-zeta activity. The treatment of cells with PKC-iota antisense oligodeoxynucleotides inhibited the effects of Ang II on the Na+/K+ATPase activity. Additionally, the effect of Ang II on Na+/K+ATPase activity was also blocked by the phosphatidylinositol 3-kinase (PI3K) inhibitors, wortmannin and LY294002, and by the actin depolymerizing agents, cytochalasin D. In conclusion, in MCF-7 cells Ang II modulates the Na+/K+ATPase activity by both atypical PKC-zeta/-iota. The effects of Ang II are opposite depending upon the presence of the serum-sensitive PKC-iota, with the inhibitory effect possibly due to the redistribution of sodium pump from plasma membrane to the inactive intracellular pool.
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Affiliation(s)
- Antonella Muscella
- Dipartimento di Scienze e Tecnologie Biologiche e Ambientali, Universitá degli Studi di Lecce, Ecotekne, Via Provinciale per Monteroni, Lecce, Italy
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