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Lewis SA, Bakhtiari S, Forstrom J, Bayat A, Bilan F, Le Guyader G, Alkhunaizi E, Vernon H, Padilla-Lopez SR, Kruer MC. AGAP1-associated endolysosomal trafficking abnormalities link gene-environment interactions in neurodevelopmental disorders. Dis Model Mech 2023; 16:dmm049838. [PMID: 37470098 PMCID: PMC10548112 DOI: 10.1242/dmm.049838] [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: 08/16/2022] [Accepted: 07/13/2023] [Indexed: 07/21/2023] Open
Abstract
AGAP1 is an Arf1 GTPase-activating protein that regulates endolysosomal trafficking. Damaging variants have been linked to cerebral palsy and autism. We report three new cases in which individuals had microdeletion variants in AGAP1. The affected individuals had intellectual disability (3/3), autism (3/3), dystonia with axial hypotonia (1/3), abnormalities of brain maturation (1/3), growth impairment (2/3) and facial dysmorphism (2/3). We investigated mechanisms potentially underlying AGAP1 variant-mediated neurodevelopmental impairments using the Drosophila ortholog CenG1a. We discovered reduced axon terminal size, increased neuronal endosome abundance and elevated autophagy compared to those in controls. Given potential incomplete penetrance, we assessed gene-environment interactions. We found basal elevation in the phosphorylation of the integrated stress-response protein eIF2α (or eIF2A) and inability to further increase eIF2α phosphorylation with subsequent cytotoxic stressors. CenG1a-mutant flies had increased lethality from exposure to environmental insults. We propose a model wherein disruption of AGAP1 function impairs endolysosomal trafficking, chronically activating the integrated stress response and leaving AGAP1-deficient cells susceptible to a variety of second-hit cytotoxic stressors. This model may have broader applicability beyond AGAP1 in instances where both genetic and environmental insults co-occur in individuals with neurodevelopmental disorders.
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Affiliation(s)
- Sara A. Lewis
- Pediatric Movement Disorders Program, Barrow Neurological Institute, Phoenix Children's Hospital, Phoenix, AZ 85016, USA
- Departments of Child Health, Neurology, Genetics and Cellular & Molecular Medicine, University of Arizona College of Medicine Phoenix, Phoenix, AZ 85004, USA
| | - Somayeh Bakhtiari
- Pediatric Movement Disorders Program, Barrow Neurological Institute, Phoenix Children's Hospital, Phoenix, AZ 85016, USA
- Departments of Child Health, Neurology, Genetics and Cellular & Molecular Medicine, University of Arizona College of Medicine Phoenix, Phoenix, AZ 85004, USA
| | - Jacob Forstrom
- Pediatric Movement Disorders Program, Barrow Neurological Institute, Phoenix Children's Hospital, Phoenix, AZ 85016, USA
- Departments of Child Health, Neurology, Genetics and Cellular & Molecular Medicine, University of Arizona College of Medicine Phoenix, Phoenix, AZ 85004, USA
| | - Allan Bayat
- Institute for Regional Health Services, University of Southern Denmark, 5230 Odense, Denmark
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center, 4293 Dianalund, Denmark
| | - Frédéric Bilan
- Service de Génétique, CHU de Poitiers, 86000 Poitiers, France
- Laboratoire de Neurosciences Experimentales et Cliniques, INSERM U1084, 86000 Poitiers, France
| | - Gwenaël Le Guyader
- Service de Génétique, CHU de Poitiers, 86000 Poitiers, France
- Laboratoire de Neurosciences Experimentales et Cliniques, INSERM U1084, 86000 Poitiers, France
| | - Ebba Alkhunaizi
- Department of Medical Genetics, North York General Hospital, Toronto, ON M3J0K2, Canada
- Division of Clinical and Metabolic Genetics, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON M3J0K2, Canada
| | - Hilary Vernon
- Department of Genetic Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Sergio R. Padilla-Lopez
- Pediatric Movement Disorders Program, Barrow Neurological Institute, Phoenix Children's Hospital, Phoenix, AZ 85016, USA
- Departments of Child Health, Neurology, Genetics and Cellular & Molecular Medicine, University of Arizona College of Medicine Phoenix, Phoenix, AZ 85004, USA
| | - Michael C. Kruer
- Pediatric Movement Disorders Program, Barrow Neurological Institute, Phoenix Children's Hospital, Phoenix, AZ 85016, USA
- Departments of Child Health, Neurology, Genetics and Cellular & Molecular Medicine, University of Arizona College of Medicine Phoenix, Phoenix, AZ 85004, USA
- Programs in Neuroscience, Molecular & Cellular Biology, and Biomedical Informatics, Arizona State University, Tempe, AZ 85287, USA
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Lewis SA, Bakhtiari S, Forstrom J, Bayat A, Bilan F, Le Guyader G, Alkhunaizi E, Vernon H, Padilla-Lopez SR, Kruer MC. AGAP1-associated endolysosomal trafficking abnormalities link gene-environment interactions in a neurodevelopmental disorder. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.31.526497. [PMID: 36778426 PMCID: PMC9915612 DOI: 10.1101/2023.01.31.526497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
AGAP1 is an Arf1 GAP that regulates endolysosomal trafficking. Damaging variants have been linked to cerebral palsy and autism. We report 3 new individuals with microdeletion variants in AGAP1 . Affected individuals have intellectual disability (3/3), autism (3/3), dystonia with axial hypotonia (1/3), abnormalities of brain maturation (1/3), growth impairment (2/3) and facial dysmorphism (2/3). We investigated mechanisms potentially underlying AGAP1 neurodevelopmental impairments using the Drosophila ortholog, CenG1a . We discovered reduced axon terminal size, increased neuronal endosome abundance, and elevated autophagy at baseline. Given potential incomplete penetrance, we assessed gene-environment interactions. We found basal elevation in phosphorylation of the integrated stress-response protein eIF2α and inability to further increase eIF2α-P with subsequent cytotoxic stressors. CenG1a -mutant flies have increased lethality from exposure to environmental insults. We propose a model wherein disruption of AGAP1 function impairs endolysosomal trafficking, chronically activating the integrated stress response, and leaving AGAP1-deficient cells susceptible to a variety of second hit cytotoxic stressors. This model may have broader applicability beyond AGAP1 in instances where both genetic and environmental insults co-occur in individuals with neurodevelopmental disorders. Summary statement We describe 3 additional patients with heterozygous AGAP1 deletion variants and use a loss of function Drosophila model to identify defects in synaptic morphology with increased endosomal sequestration, chronic autophagy induction, basal activation of eIF2α-P, and sensitivity to environmental stressors.
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Affiliation(s)
- Sara A. Lewis
- Pediatric Movement Disorders Program, Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ USA
- Departments of Child Health, Neurology, Genetics and Cellular & Molecular Medicine, University of Arizona College of Medicine Phoenix, AZ USA
| | - Somayeh Bakhtiari
- Pediatric Movement Disorders Program, Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ USA
- Departments of Child Health, Neurology, Genetics and Cellular & Molecular Medicine, University of Arizona College of Medicine Phoenix, AZ USA
| | - Jacob Forstrom
- Pediatric Movement Disorders Program, Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ USA
- Departments of Child Health, Neurology, Genetics and Cellular & Molecular Medicine, University of Arizona College of Medicine Phoenix, AZ USA
| | - Allan Bayat
- Institute for Regional Health Services, University of Southern Denmark, Odense, Denmark
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center, Dianalund, Denmark
| | - Frédéric Bilan
- Service de Génétique, CHU de Poitiers
- Laboratoire de Neurosciences Experimentales et Cliniques, INSERM U1084, Poitiers, France
| | - Gwenaël Le Guyader
- Service de Génétique, CHU de Poitiers
- Laboratoire de Neurosciences Experimentales et Cliniques, INSERM U1084, Poitiers, France
| | - Ebba Alkhunaizi
- Department of Medical Genetics, North York General Hospital, Toronto, Ontario, Canada
- Division of Clinical and Metabolic Genetics, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Hilary Vernon
- Department of Genetic Medicine, Johns Hopkins University, Baltimore, MD USA
| | - Sergio R. Padilla-Lopez
- Pediatric Movement Disorders Program, Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ USA
- Departments of Child Health, Neurology, Genetics and Cellular & Molecular Medicine, University of Arizona College of Medicine Phoenix, AZ USA
| | - Michael C. Kruer
- Pediatric Movement Disorders Program, Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ USA
- Departments of Child Health, Neurology, Genetics and Cellular & Molecular Medicine, University of Arizona College of Medicine Phoenix, AZ USA
- Programs in Neuroscience, Molecular & Cellular Biology, and Biomedical Informatics, Arizona State University, Tempe, AZ USA
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Listeria monocytogenes Co-Opts the Host Exocyst Complex To Promote Internalin A-Mediated Entry. Infect Immun 2022; 90:e0032622. [PMID: 36255255 PMCID: PMC9753705 DOI: 10.1128/iai.00326-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The bacterial pathogen Listeria monocytogenes induces its internalization (entry) into intestinal epithelial cells through interaction of its surface protein, internalin A (InlA), with the human cell-cell adhesion molecule, E-cadherin. While InlA-mediated entry requires bacterial stimulation of actin polymerization, it remains unknown whether additional host processes are manipulated to promote internalization. Here, we show that interaction of InlA with E-cadherin induces the host membrane-trafficking process of polarized exocytosis, which augments uptake of Listeria. Imaging studies revealed that exocytosis is stimulated at sites of InlA-dependent internalization. Experiments inhibiting human N-ethylmaleimide-sensitive factor (NSF) demonstrated that exocytosis is needed for efficient InlA-mediated entry. Polarized exocytosis is mediated by the exocyst complex, which comprises eight proteins, including Sec6, Exo70, and Exo84. We found that Exo70 was recruited to sites of InlA-mediated entry. In addition, depletion of Exo70, Exo84, or Sec6 by RNA interference impaired entry without affecting surface levels of E-cadherin. Similar to binding of InlA to E-cadherin, homophilic interaction of E-cadherin molecules mobilized the exocyst and stimulated exocytosis. Collectively, these results demonstrate that ligation of E-cadherin induces exocytosis that promotes Listeria entry, and they raise the possibility that the exocyst might also control the normal function of E-cadherin in cell-cell adhesion.
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Sibanda T, Buys EM. Listeria monocytogenes Pathogenesis: The Role of Stress Adaptation. Microorganisms 2022; 10:microorganisms10081522. [PMID: 36013940 PMCID: PMC9416357 DOI: 10.3390/microorganisms10081522] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 07/08/2022] [Accepted: 07/19/2022] [Indexed: 12/13/2022] Open
Abstract
Adaptive stress tolerance responses are the driving force behind the survival ability of Listeria monocytogenes in different environmental niches, within foods, and ultimately, the ability to cause human infections. Although the bacterial stress adaptive responses are primarily a necessity for survival in foods and the environment, some aspects of the stress responses are linked to bacterial pathogenesis. Food stress-induced adaptive tolerance responses to acid and osmotic stresses can protect the pathogen against similar stresses in the gastrointestinal tract (GIT) and, thus, directly aid its virulence potential. Moreover, once in the GIT, the reprogramming of gene expression from the stress survival-related genes to virulence-related genes allows L. monocytogenes to switch from an avirulent to a virulent state. This transition is controlled by two overlapping and interlinked transcriptional networks for general stress response (regulated by Sigma factor B, (SigB)) and virulence (regulated by the positive regulatory factor A (PrfA)). This review explores the current knowledge on the molecular basis of the connection between stress tolerance responses and the pathogenesis of L. monocytogenes. The review gives a detailed background on the currently known mechanisms of pathogenesis and stress adaptation. Furthermore, the paper looks at the current literature and theories on the overlaps and connections between the regulatory networks for SigB and PrfA.
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Affiliation(s)
- Thulani Sibanda
- Department of Consumer and Food Sciences, University of Pretoria, Private Bag X20, Hatfield, Pretoria 0028, South Africa;
- Department of Applied Biology and Biochemistry, National University of Science and Technology, Bulawayo P.O. Box AC939, Zimbabwe
| | - Elna M. Buys
- Department of Consumer and Food Sciences, University of Pretoria, Private Bag X20, Hatfield, Pretoria 0028, South Africa;
- Correspondence:
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Ireton K, Mortuza R, Gyanwali GC, Gianfelice A, Hussain M. Role of internalin proteins in the pathogenesis of Listeria monocytogenes. Mol Microbiol 2021; 116:1407-1419. [PMID: 34704304 DOI: 10.1111/mmi.14836] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 10/22/2021] [Indexed: 12/15/2022]
Abstract
Listeria monocytogenes is a food-borne bacterium that causes gastroenteritis, meningitis, or abortion. L. monocytogenes induces its internalization (entry) into human cells and either spreads laterally in tissues or transcytoses to traverse anatomical barriers. In this review, we discuss mechanisms by which five structurally related proteins of the "internalin" family of L. monocytogenes (InlA, InlB, InlC, InlF, and InlP) interact with distinct host receptors to promote infection of human cells and/or crossing of the intestinal, blood-brain, or placental barriers. We focus on recent results demonstrating that the internalin proteins InlA, InlB, and InlC exploit exocytic pathways to stimulate transcytosis, entry, or cell-to-cell spread, respectively. We also discuss evidence that InlA-mediated transcytosis contributes to traversal of the intestinal barrier, whereas InlF promotes entry into endothelial cells to breach the blood-brain barrier. InlB also facilitates the crossing of the blood-brain barrier, but does so by extending the longevity of infected monocytes that may subsequently act as a "Trojan horse" to transfer bacteria to the brain. InlA, InlB, and InlP each contribute to fetoplacental infection by targeting syncytiotrophoblast or cytotrophoblast layers of the placenta. This work highlights the diverse functions of internalins and the complex mechanisms by which these structurally related proteins contribute to disease.
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Affiliation(s)
- Keith Ireton
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Roman Mortuza
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | | | - Antonella Gianfelice
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Mazhar Hussain
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
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Herath TUB, Roy A, Gianfelice A, Ireton K. Shigella flexneri subverts host polarized exocytosis to enhance cell-to-cell spread. Mol Microbiol 2021; 116:1328-1346. [PMID: 34608697 DOI: 10.1111/mmi.14827] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 09/21/2021] [Accepted: 10/01/2021] [Indexed: 11/28/2022]
Abstract
Shigella flexneri is a gram-negative bacterial pathogen that causes dysentery. Critical for disease is the ability of Shigella to use an actin-based motility (ABM) process to spread between cells of the colonic epithelium. ABM transports bacteria to the periphery of host cells, allowing the formation of plasma membrane protrusions that mediate spread to adjacent cells. Here we demonstrate that efficient protrusion formation and cell-to-cell spread of Shigella involves bacterial stimulation of host polarized exocytosis. Using an exocytic probe, we found that exocytosis is locally upregulated in bacterial protrusions in a manner that depends on the Shigella type III secretion system. Experiments involving RNA interference (RNAi) indicate that efficient bacterial protrusion formation and spread require the exocyst, a mammalian multi-protein complex known to mediate polarized exocytosis. In addition, the exocyst component Exo70 and the exocyst regulator RalA were recruited to Shigella protrusions, suggesting that bacteria manipulate exocyst function. Importantly, RNAi-mediated depletion of exocyst proteins or RalA reduced the frequency of protrusion formation and also the lengths of protrusions, demonstrating that the exocyst controls both the initiation and elongation of protrusions. Collectively, our results reveal that Shigella co-opts the exocyst complex to disseminate efficiently in host cell monolayers.
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Affiliation(s)
- Thilina U B Herath
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Arpita Roy
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Antonella Gianfelice
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Keith Ireton
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
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Shahid AD, Lu Y, Iqbal MA, Lin L, Huang S, Jiang X, Chen S. Listeria monocytogenes crosses blood brain barrier through Rho GTPases induced migration of macrophages and inflammatory interleukin expression. Microb Pathog 2021; 159:105143. [PMID: 34400281 DOI: 10.1016/j.micpath.2021.105143] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 08/09/2021] [Accepted: 08/12/2021] [Indexed: 10/20/2022]
Abstract
Listeria monocytogenes crossing the blood-brain barrier in the form of "Trojan Horse" is of great significance for the establishment of bacterial encephalitis and meningitis. Induction of cell migration and crossing the blood-brain barrier is very important to understand the Listeria pathogenesis. The Rho GTPases family is considered a key factor in regulating cell migration. This study was designed to investigate the expression of Rho GTPases and their effect on the behavior of cell migration and the stimulation of immune factors. Selective Rho GTPases were investigated by real-time PCR and Western blot. Among these, the expression of RhoA was significantly increased following the infection of Listeria monocytogenes in macrophages. Further, we found that RhoA improves the migration of macrophages and expression of IL-1β, IL-6, and TNF-α. The expression of IL-1β, IL-6 and TNF-α possibly facilitates the migration and adhesion of macrophages to cross the blood-brain barrier. This study provides preliminary ground to investigate the detailed mechanism of Listeria monocytogenes crossing the blood-brain barrier.
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Affiliation(s)
| | - Ye Lu
- School of Medicine, Jiangsu University, Zhenjiang, 212013, China; Department of Clinical Laboratory, Yixing People's Hospital, Affiliated Jiangsu University, Wuxi, 214200, China
| | | | - Lin Lin
- School of Medicine, Jiangsu University, Zhenjiang, 212013, China
| | - Shuang Huang
- School of Medicine, Jiangsu University, Zhenjiang, 212013, China
| | - Xugan Jiang
- School of Medicine, Jiangsu University, Zhenjiang, 212013, China
| | - Shengxia Chen
- School of Medicine, Jiangsu University, Zhenjiang, 212013, China.
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Highland CM, Fromme JC. Arf1 directly recruits the Pik1-Frq1 PI4K complex to regulate the final stages of Golgi maturation. Mol Biol Cell 2021; 32:1064-1080. [PMID: 33788598 PMCID: PMC8101487 DOI: 10.1091/mbc.e21-02-0069] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/11/2021] [Accepted: 03/12/2021] [Indexed: 12/21/2022] Open
Abstract
Proper Golgi complex function depends on the activity of Arf1, a GTPase whose effectors assemble and transport outgoing vesicles. Phosphatidylinositol 4-phosphate (PI4P) generated at the Golgi by the conserved PI 4-kinase Pik1 (PI4KIIIβ) is also essential for Golgi function, although its precise roles in vesicle formation are less clear. Arf1 has been reported to regulate PI4P production, but whether Pik1 is a direct Arf1 effector is not established. Using a combination of live-cell time-lapse imaging analyses, acute PI4P depletion experiments, and in vitro protein-protein interaction assays on Golgi-mimetic membranes, we present evidence for a model in which Arf1 initiates the final stages of Golgi maturation by tightly controlling PI4P production through direct recruitment of the Pik1-Frq1 PI4-kinase complex. This PI4P serves as a critical signal for AP-1 and secretory vesicle formation, the final events at maturing Golgi compartments. This work therefore establishes the regulatory and temporal context surrounding Golgi PI4P production and its precise roles in Golgi maturation.
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Affiliation(s)
- Carolyn M. Highland
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | - J. Christopher Fromme
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
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