title: Endothelial Cell Proteomic Response to Rickettsia conorii Infection Reveals Activation of the Janus Kinase (JAK)-Signal Transducer and Activator of Transcription (STAT)-Inferferon Stimulated Gene (ISG)15 Pathway and Reprogramming Plasma Membrane Integrin/Cadherin Signaling.
abstract: Rickettsia conorii is the etiologic agent of Mediterranean spotted fever, a re-emerging infectious disease with significant mortality. This Gram-negative, obligately intracellular pathogen is transmitted via tick bites, resulting in disseminated vascular endothelial cell infection with vascular leakage. In the infected human, Rickettsia conorii infects endothelial cells, stimulating expression of cytokines and pro-coagulant factors. However, the integrated proteomic response of human endothelial cells to R. conorii infection is not known. In this study, we performed quantitative proteomic profiling of primary human umbilical vein endothelial cells (HUVECs) with established R conorii infection versus those stimulated with endotoxin (LPS) alone. We observed differential expression of 55 proteins in HUVEC whole cell lysates. Of these, we observed induction of signal transducer and activator of transcription (STAT)1, MX dynamin-like GTPase (MX1), and ISG15 ubiquitin-like modifier, indicating activation of the JAK-STAT signaling pathway occurs in R. conorii-infected HUVECs. The down-regulated proteins included those involved in the pyrimidine and arginine biosynthetic pathways. A highly specific biotinylated cross-linking enrichment protocol was performed to identify dysregulation of 11 integral plasma membrane proteins that included up-regulated expression of a sodium/potassium transporter and down-regulation of α-actin 1. Analysis of Golgi and soluble Golgi fractions identified up-regulated proteins involved in platelet-endothelial adhesion, phospholipase activity, and IFN activity. Thirty four rickettsial proteins were identified with high confidence in the Golgi, plasma membrane, or secreted protein fractions. The host proteins associated with rickettsial infections indicate activation of interferon-STAT signaling pathways; the disruption of cellular adhesion and alteration of antigen presentation pathways in response to rickettsial infections are distinct from those produced by nonspecific LPS stimulation. These patterns of differentially expressed proteins suggest mechanisms of pathogenesis as well as methods for diagnosis and monitoring Rickettsia infections.
authors.affiliation: From the Departments of ‡Internal Medicine and §Institute for Translational Sciences, and ¶Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas 77555-1060.
authors.forename: Yingxin
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: §Institute for Translational Sciences, and ‖Pathology.
authors.forename: Gustavo
authors.initials: G
authors.lastname: Valbuena
authors.affiliation: ‖Pathology.
authors.forename: David H
authors.initials: DH
authors.lastname: Walker
authors.affiliation: ‖Pathology.
authors.forename: Michal
authors.initials: M
authors.lastname: Gazi
authors.affiliation: the **Microbiology Department, Faculty of Sciences, Pontificia Universidad Javeriana, Bogotá, Colombia.
authors.forename: Marylin
authors.initials: M
authors.lastname: Hidalgo
authors.affiliation: the ‡‡Centre for the Study of Vectors and Infectious Diseases Dr. Francisco Cambournac, National Institute of Health Dr. Ricardo Jorge, Águas de Moura, Av. Padre Cruz, Lisbon, 1649-016, Portugal, and.
authors.forename: Rita
authors.initials: R
authors.lastname: DeSousa
authors.affiliation: the §§Centre of Rickettsiosis and Arthropod-Borne Diseases, Hospital San Pedro-Centro de Investigation Biomedical de la Rioja (CIBIR), Logroño, La Rioja, 26006, Spain.
authors.forename: Jose Antonio
authors.initials: JA
authors.lastname: Oteo
authors.affiliation: ‖Pathology.
authors.forename: Yenny
authors.initials: Y
authors.lastname: Goez
authors.affiliation: From the Departments of ‡Internal Medicine and §Institute for Translational Sciences, and ¶Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas 77555-1060, arbrasie@utmb.edu.
authors.forename: Allan R
authors.initials: AR
authors.lastname: Brasier
mesh_terms: D015820:Cadherins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D002853:Chromatography, Liquid; D016207:Cytokines / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism; D054884:Host-Pathogen Interactions; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects / Q000378:metabolism* / Q000382:microbiology; D006801:Humans; D016023:Integrins / Q000378:metabolism*; D053612:Janus Kinases / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008565:Membrane Proteins / Q000378:metabolism; D020543:Proteome / Q000378:metabolism; D040901:Proteomics / Q000379:methods*; D020114:Rickettsia conorii / Q000502:physiology; D050794:STAT1 Transcription Factor / Q000378:metabolism*; D015398:Signal Transduction; D053719:Tandem Mass Spectrometry; D014452:Ubiquitins / Q000378:metabolism*
chemical_list: D015820:Cadherins; D016207:Cytokines; D016023:Integrins; D008070:Lipopolysaccharides; D008565:Membrane Proteins; D020543:Proteome; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D014452:Ubiquitins; C074034:ISG15 protein, human; D053612:Janus Kinases