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Kim Y, Clemens EG, Farner JM, Londono-Barbaran A, Grab DJ, Dumler JS. Spotted fever rickettsia-induced microvascular endothelial barrier dysfunction is delayed by the calcium channel blocker benidipine. Biochem Biophys Res Commun 2023; 663:96-103. [PMID: 37121130 PMCID: PMC10362780 DOI: 10.1016/j.bbrc.2023.04.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 04/17/2023] [Indexed: 05/02/2023]
Abstract
The tick-borne bacterium Rickettsia parkeri is an obligate intracellular pathogen that belongs to spotted fever group rickettsia (SFGR). The SFG pathogens are characterized by their ability to infect and rapidly proliferate inside host vascular endothelial cells that eventually result in impairment of vascular endothelium barrier functions. Benidipine, a wide range dihydropyridine calcium channel blocker, is used to prevent and treat cardiovascular diseases. In this study, we tested whether benidipine has protective effects against rickettsia-induced microvascular endothelial cell barrier dysfunction in vitro. We utilized an in vitro vascular model consisting of transformed human brain microvascular endothelial cells (tHBMECs) and continuously monitored transendothelial electric resistance (TEER) across the cell monolayer. We found that during the late stages of infection when we observed TEER decrease and when there was a gradual increase of the cytoplasmic [Ca2+], benidipine prevented these rickettsia-induced effects. In contrast, nifedipine, another cardiovascular dihydropyridine channel blocker specific for L-type Ca2+ channels, did not prevent R. parkeri-induced drop of TEER. Additionally, neither drug was bactericidal. These data suggest that growth of R. parkeri inside endothelial cells is associated with impairment of endothelial cell monolayer integrity due to Ca2+ flooding through specific, benidipine-sensitive T- or N/Q-type Ca2+ channels but not through nifedipine-sensitive L-type Ca2+ channels. Further study will be required to discern the exact nature of the Ca2+ channels and Ca2+ transporting system(s) involved, any contributions of the pathogen toward this process, as well as the suitability of benidipine and new dihydropyridine derivatives as complimentary therapeutic drugs against Rickettsia-induced vascular failure.
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Affiliation(s)
- Yuri Kim
- Henry M. Jackson Foundation for the Advancement of Military Medicine, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA; Uniformed Services of the Health Sciences, Department of Pathology, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA.
| | - Emily G Clemens
- Uniformed Services of the Health Sciences, Department of Pathology, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA.
| | - Jennifer M Farner
- Henry M. Jackson Foundation for the Advancement of Military Medicine, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA; Uniformed Services of the Health Sciences, Department of Pathology, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA.
| | - Andres Londono-Barbaran
- Henry M. Jackson Foundation for the Advancement of Military Medicine, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA; Uniformed Services of the Health Sciences, Department of Pathology, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA.
| | - Dennis J Grab
- Uniformed Services of the Health Sciences, Department of Pathology, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA.
| | - J Stephen Dumler
- Uniformed Services of the Health Sciences, Department of Pathology, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA.
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CNS-infecting pathogens Escherichia coli and Cryptococcus neoformans exploit the host Pdlim2 for intracellular traversal and exocytosis in the blood-brain barrier. Infect Immun 2021; 89:e0012821. [PMID: 34228504 DOI: 10.1128/iai.00128-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Microbial penetration of the blood-brain barrier, a prerequisite for development of the central nervous system (CNS) infection, involves microbial invasion, intracellular traversal and exocytosis. Microbial invasion of the blood-brain barrier has been investigated, but the molecular basis for microbial traversal and exit from the blood-brain barrier remains unknown. We performed transcriptome analysis of the human brain microvascular endothelial cell (HBMEC) infected with Escherichia coli and Cryptococcus neoformans, representative bacterial and fungal pathogens common in CNS infection. Among the upregulated targets in response to E. coli and C. neoformans infection, PDLIM2 was knocked down by shRNA in HBMEC for further investigation. We demonstrated that Pdlim2 specifically regulated the microbial traversal and exit from HBMEC by assessing microbial invasion, transcytosis, intracellular multiplication and egression. Additionally, the defective exocytosis of internalized E. coli from the PDLIM2 shRNA knockdown cell was restored by treatment with a calcium ionophore (ionomycin). Moreover, we performed the proximity-dependent biotin labeling with the biotin ligase BioID2 and identified 210 potential Pdlim2-interactors. Among the nine enriched Pdlim2-interactors in response to both E. coli and C. neoformans infection, we selected MPRIP and showed that HBMEC with knockdown of MPRIP mimicked the phenotype of PDLIM2 knockdown cell. These results suggest that the CNS-infecting microbes hijack Pdlim2 and Mprip for intracellular traversal and exocytosis in the blood-brain barrier.
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Hsu SS, Liang WZ. Cytotoxic Effects of Mesaconitine, the Aconitum carmichaelii Debx Bioactive Compound, on HBEC-5i Human Brain Microvascular Endothelial Cells: Role of Ca 2+ Signaling-Mediated Pathway. Neurotox Res 2020; 39:256-265. [PMID: 32588354 DOI: 10.1007/s12640-020-00249-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 05/30/2020] [Accepted: 06/22/2020] [Indexed: 10/24/2022]
Abstract
Mesaconitine, one of Aconitum carmichaelii Debx bioactive compounds, was shown to evoke Ca2+ homeostasis and its related physiological effects in endothelial cell types. However, the effect of mesaconitine on Ca2+ signaling and cell viability in human brain microvascular endothelial cells is unclear. This study focused on exploring whether mesaconitine changed cytosolic Ca2+ concentrations ([Ca2+]i), affected cell viability, and established the relationship between Ca2+ signaling and viability in HBEC-5i human brain microvascular endothelial cells. In HBEC-5i cells, cell viability was measured by the cell proliferation reagent (WST-1). [Ca2+]i was measured by the Ca2+-sensitive fluorescent dye fura-2. Mesaconitine (10-100 μM) concentration dependently induced [Ca2+]i rises. Ca2+ removal reduced the signal by approximately 25%. Mesaconitine (40-100 μM) caused cytotoxicity in HBEC-5i cells. This cytotoxic response was significantly reversed by chelation of cytosolic Ca2+ with BAPTA/AM. In Ca2+-containing medium, mesaconitine-induced Ca2+ entry was inhibited by 25% by modulators of store-operated Ca2+ channels and protein kinase C (PKC). Furthermore, mesaconitine also induced Mn2+ influx suggesting of Ca2+ entry. In Ca2+-free medium, treatment with the endoplasmic reticulum Ca2+ pump inhibitor thapsigargin abolished mesaconitine-evoked [Ca2+]i rises. Conversely, treatment with mesaconitine abolished thapsigargin-evoked [Ca2+]i rises. Inhibition of phospholipase C (PLC) with U73122 abolished mesaconitine-induced [Ca2+]i rises. In sum, mesaconitine caused cytotoxicity that was triggered by preceding [Ca2+]i rises. Furthermore, mesaconitine induced [Ca2+]i rises by evoking Ca2+ entry via PKC-sensitive store-operated Ca2+ channels and PLC-dependent Ca2+ release from the endoplasmic reticulum. It suggests that Ca2+ signaling have a potential cytotoxic effect on mesaconitine-treated human brain microvascular endothelial cells.
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Affiliation(s)
- Shu-Shong Hsu
- Department of Surgery, Kaohsiung Veterans General Hospital, Kaohsiung, 81362, Taiwan.,Department of Surgery, National Defense Medical Center, Taipei, 11490, Taiwan.,College of Health and Nursing, Meiho University, Neipu, Pingtung, 91202, Taiwan
| | - Wei-Zhe Liang
- Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung, 81362, Taiwan. .,Department of Pharmacy and Master Program, College of Pharmacy and Health Care, Tajen University, Pingtung County, 90741, Taiwan.
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Kim KS. Investigating Bacterial Penetration of the Blood-Brain Barrier for the Pathogenesis, Prevention, and Therapy of Bacterial Meningitis. ACS Infect Dis 2020; 6:34-42. [PMID: 31805229 DOI: 10.1021/acsinfecdis.9b00319] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The most distressing aspect of bacterial meningitis is limited improvement in the mortality and morbidity despite attributable advances in antimicrobial chemotherapy and supportive care. A major contributing factor to such mortality and morbidity is our incomplete understanding of the pathogenesis of this disease. Microbial penetration of the blood-brain barrier, a prerequisite for the development of bacterial meningitis, exploits specific host and bacterial factors as well as host cell signaling molecules. Determination and characterization of such host and bacterial factors have been instrumental for developing our current knowledge on the pathogenesis of bacterial meningitis. In addition, counteracting such host and microbial factors has been shown to be efficacious in the prevention of bacterial meningitis. Antimicrobial therapy alone has limited efficacy in improving the outcome of bacterial meningitis. Recent studies suggest that counteracting targets contributing to bacterial penetration of the blood-brain barrier are a beneficial therapeutic adjunct to antimicrobial therapy in improving the outcome of bacterial meningitis. Taken together, these findings indicate that the elucidation of host and bacterial factors contributing to microbial penetration of the blood-brain barrier provides a novel strategy for investigating the pathogenesis, prevention, and therapy of bacterial meningitis.
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Affiliation(s)
- Kwang Sik Kim
- Division of Pediatric Infectious Diseases, Johns Hopkins University School of Medicine, 200 North Wolfe Street, Room 3157, Baltimore, Maryland 21287, United States
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Liu R, Wu C, Li L, Chi F, Zhang T, Xu Y, Ji L, Chen Z, Hu H, Zhang X, Huang S, Wang L. CD48 and α7 Nicotinic Acetylcholine Receptor Synergistically Regulate FimH-Mediated Escherichia coli K1 Penetration and Neutrophil Transmigration Across Human Brain Microvascular Endothelial Cells. J Infect Dis 2019; 219:470-479. [PMID: 30202861 PMCID: PMC6325351 DOI: 10.1093/infdis/jiy531] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Accepted: 08/31/2018] [Indexed: 11/12/2022] Open
Abstract
FimH-mediated bacterial invasion and polymorphonuclear neutrophil (PMN) transmigration across human brain microvascular endothelial cells (HBMECs) are required for the pathogenesis of Escherichia coli meningitis. However, the underlying mechanism remains unclear. This study demonstrated that the TnphoA mutant (22A33) and FimH-knockout mutant (ΔFimH) of E coli strain E44, which resulted in inactivation of FimH, were less invasive and less effective in promoting PMN transmigration than their wild-type strain. FimH protein induced PMN transmigration, whereas calmodulin inhibitor significantly blocked this effect. Moreover, immunofluorescence and co-immunoprecipitation analysis indicated that colocalized CD48 and α7 nAChR formed a complex on the surface of HBMECs that is associated with increased cofilin dephosphorylation, which could be remarkably enhanced by FimH+ E44. Our study concluded that FimH-induced E coli K1 invasion and PMN migration across HBMECs may be mediated by the CD48-α7nAChR complex in lipid rafts of HBMEC via Ca2+ signaling and cofilin dephosphorylation.
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Affiliation(s)
- Rui Liu
- Department of Histology and Embryology, School of Basic Medical Sciences, Wuhan University, China
- Department of Human Anatomy, School of Basic Medical Sciences, Hubei University of Medicine, Shiyan, China
| | - Chao Wu
- Department of Histology and Embryology, School of Basic Medical Sciences, Wuhan University, China
| | - Li Li
- Kunming Key Laboratory of Children Infection and Immunity, Yunnan Institute of Pediatrics, Kunming Children’s Hospital, China
- Department of Pediatrics, Saban Research Institute, University of Southern California, Childrens Hospital Los Angeles
| | - Feng Chi
- Department of Pediatrics, Saban Research Institute, University of Southern California, Childrens Hospital Los Angeles
| | - Tiesong Zhang
- Kunming Key Laboratory of Children Infection and Immunity, Yunnan Institute of Pediatrics, Kunming Children’s Hospital, China
| | - Yating Xu
- Department of Histology and Embryology, School of Basic Medical Sciences, Wuhan University, China
| | - Lulu Ji
- Department of Histology and Embryology, School of Basic Medical Sciences, Wuhan University, China
| | - Zhiguo Chen
- Department of Histology and Embryology, School of Basic Medical Sciences, Wuhan University, China
| | - Hanyang Hu
- Department of Histology and Embryology, School of Basic Medical Sciences, Wuhan University, China
| | - Xiaoli Zhang
- Department of Ultrasound Imaging, Zhongnan Hospital of Wuhan University, China
| | - Shenghe Huang
- Department of Pediatrics, Saban Research Institute, University of Southern California, Childrens Hospital Los Angeles
- Department of Microbiology, School of Public Health and Tropocal Medicine, Southern Medical University, Guangzhou, China
| | - Lin Wang
- Department of Histology and Embryology, School of Basic Medical Sciences, Wuhan University, China
- Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan, China
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Abstract
Escherichia coli is the most common Gram-negative bacillary organism causing meningitis, and E. coli meningitis continues to be an important cause of mortality and morbidity throughout the world. Our incomplete knowledge of its pathogenesis contributes to such mortality and morbidity. Recent reports of E. coli strains producing CTX-M-type or TEM-type extended-spectrum β-lactamases create a challenge. Studies using in vitro and in vivo models of the blood-brain barrier have shown that E. coli meningitis follows a high degree of bacteremia and invasion of the blood-brain barrier. E. coli invasion of the blood-brain barrier, the essential step in the development of E. coli meningitis, requires specific microbial and host factors as well as microbe- and host-specific signaling molecules. Blockade of such microbial and host factors contributing to E. coli invasion of the blood-brain barrier is shown to be efficient in preventing E. coli penetration into the brain. The basis for requiring a high degree of bacteremia for E. coli penetration of the blood-brain barrier, however, remains unclear. Continued investigation on the microbial and host factors contributing to a high degree of bacteremia and E. coli invasion of the blood-brain barrier is likely to identify new targets for prevention and therapy of E. coli meningitis.
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A journey into the brain: insight into how bacterial pathogens cross blood-brain barriers. Nat Rev Microbiol 2017; 15:149-159. [PMID: 28090076 DOI: 10.1038/nrmicro.2016.178] [Citation(s) in RCA: 155] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The blood-brain barrier, which is one of the tightest barriers in the body, protects the brain from insults, such as infections. Indeed, only a few of the numerous blood-borne bacteria can cross the blood-brain barrier to cause meningitis. In this Review, we focus on invasive extracellular pathogens, such as Neisseria meningitidis, Streptococcus pneumoniae, group B Streptococcus and Escherichia coli, to review the obstacles that bacteria have to overcome in order to invade the meninges from the bloodstream, and the specific skills they have developed to bypass the blood-brain barrier. The medical importance of understanding how these barriers can be circumvented is underlined by the fact that we need to improve drug delivery into the brain.
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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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Karassek S, Starost L, Solbach J, Greune L, Sano Y, Kanda T, Kim K, Schmidt MA. Pertussis Toxin Exploits Specific Host Cell Signaling Pathways for Promoting Invasion and Translocation of Escherichia coli K1 RS218 in Human Brain-derived Microvascular Endothelial Cells. J Biol Chem 2015; 290:24835-43. [PMID: 26324705 DOI: 10.1074/jbc.m115.650101] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Indexed: 01/23/2023] Open
Abstract
Pertussis toxin (PTx), an AB5 toxin and major virulence factor of the whooping cough-causing pathogen Bordetella pertussis, has been shown to affect the blood-brain barrier. Dysfunction of the blood-brain barrier may facilitate penetration of bacterial pathogens into the brain, such as Escherichia coli K1 (RS218). In this study, we investigated the influence of PTx on blood-brain barrier permissiveness to E. coli infection using human brain-derived endothelial HBMEC and TY10 cells as in vitro models. Our results indicate that PTx acts at several key points of host cell intracellular signaling pathways, which are also affected by E. coli K1 RS218 infection. Application of PTx increased the expression of the pathogen binding receptor gp96. Further, we found an activation of STAT3 and of the small GTPase Rac1, which have been described as being essential for bacterial invasion involving host cell actin cytoskeleton rearrangements at the bacterial entry site. In addition, we showed that PTx induces a remarkable relocation of VE-cadherin and β-catenin from intercellular junctions. The observed changes in host cell signaling molecules were accompanied by differences in intracellular calcium levels, which might act as a second messenger system for PTx. In summary, PTx not only facilitates invasion of E. coli K1 RS218 by activating essential signaling cascades; it also affects intercellular barriers to increase paracellular translocation.
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Affiliation(s)
- Sascha Karassek
- From the Institute of Infectiology, Center for Molecular Biology of Inflammation, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany
| | - Laura Starost
- From the Institute of Infectiology, Center for Molecular Biology of Inflammation, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany
| | - Johanna Solbach
- From the Institute of Infectiology, Center for Molecular Biology of Inflammation, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany
| | - Lilo Greune
- From the Institute of Infectiology, Center for Molecular Biology of Inflammation, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany
| | - Yasuteru Sano
- the Department of Neurology and Clinical Neuroscience, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan, and
| | - Takashi Kanda
- the Department of Neurology and Clinical Neuroscience, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan, and
| | - KwangSik Kim
- the Pediatric Infectious Diseases Division, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287
| | - M Alexander Schmidt
- From the Institute of Infectiology, Center for Molecular Biology of Inflammation, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany,
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De Bock M, Wang N, Decrock E, Bol M, Gadicherla AK, Culot M, Cecchelli R, Bultynck G, Leybaert L. Endothelial calcium dynamics, connexin channels and blood-brain barrier function. Prog Neurobiol 2013; 108:1-20. [PMID: 23851106 DOI: 10.1016/j.pneurobio.2013.06.001] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 06/12/2013] [Accepted: 06/18/2013] [Indexed: 01/11/2023]
Abstract
Situated between the circulation and the brain, the blood-brain barrier (BBB) protects the brain from circulating toxins while securing a specialized environment for neuro-glial signaling. BBB capillary endothelial cells exhibit low transcytotic activity and a tight, junctional network that, aided by the cytoskeleton, restricts paracellular permeability. The latter is subject of extensive research as it relates to neuropathology, edema and inflammation. A key determinant in regulating paracellular permeability is the endothelial cytoplasmic Ca(2+) concentration ([Ca(2+)]i) that affects junctional and cytoskeletal proteins. Ca(2+) signals are not one-time events restricted to a single cell but often appear as oscillatory [Ca(2+)]i changes that may propagate between cells as intercellular Ca(2+) waves. The effect of Ca(2+) oscillations/waves on BBB function is largely unknown and we here review current evidence on how [Ca(2+)]i dynamics influence BBB permeability.
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Affiliation(s)
- Marijke De Bock
- Dept. of Basic Medical Sciences, Ghent University, Ghent, Belgium.
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Genome-wide association analysis of avian resistance to Campylobacter jejuni colonization identifies risk locus spanning the CDH13 gene. G3-GENES GENOMES GENETICS 2013; 3:881-90. [PMID: 23550144 PMCID: PMC3656734 DOI: 10.1534/g3.113.006031] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The enteropathogen Campylobacter jejuni is a major worldwide health and economic burden, being one of the leading causes of bacterial gastroenteritis and commonly linked to postinfectious onset of autoimmune disease. Chickens are a major vector for human infection and even though variation in avian colonization level is heritable, no previous studies have identified regions of the genome associated with colonization resistance. We performed a genome-wide association study of resistance to C. jejuni colonization in the avian intestine by controlling for population structure, which revealed a risk locus with genome-wide significance spanning the T-cadherin (CDH13) gene. A second possible risk locus was also identified close to calmodulin (CALM1), a calcium-activated modulator of cadherin function. In addition, gene expression analysis of mRNA sequencing profiles revealed that the relative expression of the two genes is significantly associated with colonization resistance. Functional studies have previously demonstrated involvement of cadherins and calmodulin in C. jejuni intracellular invasion and colonization of human intestinal epithelial cells in vitro. Consistent with this finding, our analysis reveals that variation surrounding these genes is associated with avian colonization resistance in vivo and highlights their potential as possible targets for control of the bacterium in avian and human populations.
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Minnaard J, Rolny IS, Pérez PF. Interaction between Bacillus cereus and cultured human enterocytes: effect of calcium, cell differentiation, and bacterial extracellular factors. J Food Prot 2013; 76:820-6. [PMID: 23643123 DOI: 10.4315/0362-028x.jfp-12-294] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Bacillus cereus interaction with cultured human enterocytes and the signaling pathways responsible for the biological effects of the infection were investigated. Results demonstrate that calcium depletion increases the ability of strains T1 and 2 to invade cells. Bacteria associated in greater extent to undifferentiated enterocytes and extracellular factors from strain 2 increased its own association and invasion. Inhibitors of signaling pathways related to phosphorylated lipids (U73122 and wortmannin) were able to significantly reduce cytoskeleton disruption induced by B. cereus infection. Adhesion of strain T1 decreased in the presence of U73122 and of wortmannin, as well as when those inhibitors were used together. In contrast, invasion values were diminished only by U73122. Results show that different factors are involved in the interaction between B. cereus and cultured human enterocytes. Following infection, disruption of the cytoskeleton could facilitate invasion of the eukaryotic cells.
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Affiliation(s)
- Jessica Minnaard
- Centro de Investigación y Desarrollo en Criotecnología de Alimentos (Consejo Nacional de Investigaciones Científicas y Técnicas [CONICET], La Plata), Calle 47 y 116-B1900AJI, La Plata, Argentina.
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Krishnan S, Fernandez GE, Sacks DB, Prasadarao NV. IQGAP1 mediates the disruption of adherens junctions to promote Escherichia coli K1 invasion of brain endothelial cells. Cell Microbiol 2012; 14:1415-33. [PMID: 22519731 DOI: 10.1111/j.1462-5822.2012.01805.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 04/09/2012] [Accepted: 04/16/2012] [Indexed: 12/17/2022]
Abstract
The transcellular entry of Escherichia coli K1 through human brain microvascular endothelial cells (HBMEC) is responsible for tight junction disruption, leading to brain oedema in neonatal meningitis. Previous studies demonstrated that outer membrane protein A (OmpA) of E. coli K1 interacts with its receptor, Ecgp96, to induce PKC-α phosphorylation, adherens junction (AJ) disassembly (by dislodging β-catenin from VE-cadherin), and remodelling of actin in HBMEC. We report here that IQGAP1 mediates β-catenin dissociation from AJs to promote actin polymerization required for E. coli K1 invasion of HBMEC. Overexpression of C-terminal truncated IQGAP1 (IQΔC) that cannot bind β-catenin prevents both AJ disruption and E. coli K1 entry. Of note, phospho-PKC-α interacts with the C-terminal portion of Ecgp96 as well as with VE-cadherin after IQGAP1-mediated AJ disassembly. HBMEC overexpressing either C-terminal truncated Ecgp96 (Ecgp96Δ200) or IQΔC upon infection with E. coli showed no interaction of phospho-PKC-α with Ecgp96. These data indicate that the binding of OmpA to Ecgp96 induces PKC-α phosphorylation and association of phospho-PKC-α with Ecgp96, and then signals IQGAP1 to detach β-catenin from AJs. Subsequently, IQGAP1/β-catenin bound actin translocates to the site of E. coli K1 attachment to promote invasion.
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Affiliation(s)
- Subramanian Krishnan
- Division of Infectious Diseases, Department of Pediatrics, The Saban Research Institute, Children's Hospital Los Angeles, University of Southern California School of Medicine, Los Angeles, CA 90027, USA
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Krzymińska S, Ochocka K, Kaznowski A. Apoptosis of epithelial cells and macrophages due to nonpigmented Serratia marcescens strains. ScientificWorldJournal 2012; 2012:679639. [PMID: 22649305 PMCID: PMC3354595 DOI: 10.1100/2012/679639] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 12/29/2011] [Indexed: 11/17/2022] Open
Abstract
Serratia marcescens strains are opportunistic pathogens that are increasingly recognized as a cause of severe nosocomial infections. In this study we observed interactions between nonpigmented strains with human epithelial and macrophage-like cells. The strains revealed hemolytic activity only after the contact of the cells with erythrocytes. The contact of the bacteria with the host cells was also essential to their cytotoxicity. Moreover, all strains revealed adherence ability and were invasive to epithelial cells. Analyses of cellular morphology and DNA fragmentation of the HEp-2 and J774 cells exhibited typical features of cells undergoing apoptosis. We observed morphological changes, including condensation of nuclear chromatin and formation of membrane-bound apoptotic bodies. The lowest apoptotic index in HEp-2 cells did not exceed 25%, whereas the highest reached 59% at 24 h and 72% at 48 h after infection. Most of the strains (60%) induced fragmentation of nuclear DNA. The process depended on the activation of caspases, and was completely blocked by the pan-caspase inhibitor z-VAD-fmk. This study provided new insights into the mechanisms of nonpigmented S. marcescens pathogenesis. The results revealed that the strains produce cell-contact toxins that facilitate bacterial invasion, induce hemolysis, cytotoxicity, and apoptosis of host cells.
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Affiliation(s)
- Sylwia Krzymińska
- Department of Microbiology, Faculty of Biology, A Mickiewicz University, Ulica Umultowska 89, 61-614 Poznań, Poland.
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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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Socha MJ, Hakim CH, Jackson WF, Segal SS. Temperature effects on morphological integrity and Ca²⁺ signaling in freshly isolated murine feed artery endothelial cell tubes. Am J Physiol Heart Circ Physiol 2011; 301:H773-83. [PMID: 21705671 DOI: 10.1152/ajpheart.00214.2011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
To study Ca(2+) signaling in the endothelium of murine feed arteries, we determined the in vitro stability of endothelial cell (EC) tubes freshly isolated from abdominal muscle feed arteries of male and female C57BL/6 mice (5-9 mo, 25-35 g). We tested the hypothesis that intracellular Ca(2+) concentration ([Ca(2+)](i)) responses to muscarinic receptor activation would increase with temperature. Intact EC tubes (length: 1-2 mm, width: 65-80 μm) were isolated using gentle enzymatic digestion with trituration to remove smooth muscle cells. A freshly isolated EC tube was secured in a chamber and superfused at 24 (room temperature), 32, or 37°C. Using fura-2 dye, [Ca(2+)](i) was monitored (ratio of fluorescence at 340- to 380-nm wavelength) at rest and in response to bolus doses of ACh (20 nmol to 200 μmol). The morphological integrity of EC tubes was preserved at 24 and 32°C. Based on the Ca(2+) K(d) values we determined for fura-2 (174 nM at 24°C and 146 nM at 32°C), resting [Ca(2+)](i) remained stable for 180 min at both 24 and 32°C (27 ± 4 and 34 ± 2 nM, respectively), with peak responses to ACh (20 μmol) increasing from ∼220 nM at 24°C to ∼500 nM at 32°C (P < 0.05). There was no difference in responses to ACh between EC tubes from male versus female mice. When EC tubes were maintained at 37°C (typical in vivo temperature), resting [Ca(2+)](i) increased by ∼30% within 15 min, and gaps formed between individual ECs as they retracted and extruded dye, precluding further study. We conclude that EC tubes enable Ca(2+) signaling to be evaluated in the freshly isolated endothelium of murine feed arteries. While Ca(2+) responses are enhanced by approximately twofold at 32 versus 24°C, the instability of EC tubes at 37°C precludes their study at typical body temperature.
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Affiliation(s)
- Matthew J Socha
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri 65212, USA
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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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Grab D, Nyarko E, Nikolskaia O, Kim Y, Dumler J. Human brain microvascular endothelial cell traversal by Borrelia burgdorferi requires calcium signaling. Clin Microbiol Infect 2009; 15:422-6. [DOI: 10.1111/j.1469-0691.2009.02869.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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In vivo demonstration and quantification of intracellular Bacillus anthracis in lung epithelial cells. Infect Immun 2008; 76:3975-83. [PMID: 18625737 DOI: 10.1128/iai.00282-08] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Inhalational anthrax is initiated by the entry of Bacillus anthracis spores into the lung. A critical early event in the establishment of an infection is the dissemination of spores from the lung. Using in vitro cell culture assays, we previously demonstrated that B. anthracis spores are capable of entering into epithelial cells of the lung and crossing a barrier of lung epithelial cells without apparent disruption of the barrier integrity, suggesting a novel portal for spores to disseminate from the lung. However, in vivo evidence for spore uptake by epithelial cells has been lacking. Here, using a mouse model, we present evidence that B. anthracis spores are taken up by lung epithelial cells in vivo soon after spores are delivered into the lung. Immunofluorescence staining of thin sections of lungs from spore-challenged BALB/c mice revealed that spores were associated with the epithelial surfaces in the airway and the alveoli at 2 and 4 h postinoculation. Confocal analysis further indicated that some of the associated spores were surrounded by F-actin, demonstrating intracellular localization. These observations were further confirmed and substantiated by a quantitative method that first isolated lung cells from spore-challenged mice and then stained these cells with antibodies specific for epithelial cells and spores. The results showed that substantial amounts of spores were taken up by lung epithelial cells in vivo. These data, combined with those in our previous reports, provided powerful evidence that the lung epithelia were directly targeted by B. anthracis spores at early stages of infection.
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