The gram-negative bacterium E. coli K1 is the leading cause of meningitis during the neonatal period. The mortality and long-term morbidity rates associated with E. coli meningitis have remained relatively unchanged despite the availability of active antimicrobial agents. The disease is fatal in 5% to 40% of infected neonates. Incomplete understanding of the pathogenesis and pathophysiology of this infection has hampered attempts to develop novel therapeutic approaches for this deadly disease. A characteristic pathophysiological feature of E. coli K1 meningitis is the disruption of the blood-brain barrier (BBB), and is mainly attributed for the neurological sequelae of this disease. However, the mechanisms by which E. coli K1 disrupts the BBB are poorly understood. We have demonstrated that E. coli K1 interacts with GlcNAd, 4GlcNAc epitopes and the protein backbone of a novel brain microvascular endothelial cell (BMEC) glycoprotein receptor (Ecgp) to invade BMEC, an in vitro model of the BBB. In addition, OmpA-Ecgp mediated invasion of E. coli also increases the permeability of the BBB both in vitro and in the animal model. Anti-Ecgp antibodies exhibited significant inhibitory effect on E. coli invasion and on the permeability of BMEC. We have also grossly defined the structural motifs of Ecgp required for interaction with OmpA by mutational analysis. We further demonstrated that E. coli K1 invasion via Ecgp induces several signaling cascades for invasion as well as to increase the permeability of the BBB. Therefore, we hypothesize that binding of OmpA to Ecgp is essential to initiate signaling events that induce E. coli invasion and increased permeability of the BBB. The project includes three specific aims: 1. To further characterize the domains of Ecgp that interact with OmpA for their ability to mediate E. coli invasion of HBMEC as well as increased BBB permeability. 2. To determine whether the interaction of the C-terminal domains of Ecgp with caveolin-1 initiates the internalization of E. coli and alter the BBB permeability via eNOS activation. 3. To examine whether blocking of OmpA-Ecgp interaction by peptides and non-peptide molecules prevent the E. coli invasion and associated BBB permeability. A better understanding of Ecgp interaction with OmpA will help elucidate the molecular mechanisms involved in the development of E. coli meningitis. Screening of small molecule antagonists to Ecgp function will lay the foundation for the development of new therapeutic strategies to prevent this deadly disease.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI040567-15
Application #
7810728
Study Section
Host Interactions with Bacterial Pathogens Study Section (HIBP)
Program Officer
Korpela, Jukka K
Project Start
1997-01-01
Project End
2011-04-30
Budget Start
2010-05-01
Budget End
2011-04-30
Support Year
15
Fiscal Year
2010
Total Cost
$371,317
Indirect Cost
Name
Children's Hospital of Los Angeles
Department
Type
DUNS #
052277936
City
Los Angeles
State
CA
Country
United States
Zip Code
90027
Griffith, Adam R; Rogers, Claude J; Miller, Gregory M et al. (2017) Predicting glycosaminoglycan surface protein interactions and implications for studying axonal growth. Proc Natl Acad Sci U S A 114:13697-13702
Cvicek, Vaclav; Goddard 3rd, William A; Abrol, Ravinder (2016) Structure-Based Sequence Alignment of the Transmembrane Domains of All Human GPCRs: Phylogenetic, Structural and Functional Implications. PLoS Comput Biol 12:e1004805
Dong, Sijia S; Goddard 3rd, William A; Abrol, Ravinder (2016) Conformational and Thermodynamic Landscape of GPCR Activation from Theory and Computation. Biophys J 110:2618-29
Krishnan, Subramanian; Chang, Alexander C; Stoltz, Brian M et al. (2016) Escherichia coli K1 Modulates Peroxisome Proliferator-Activated Receptor ? and Glucose Transporter 1 at the Blood-Brain Barrier in Neonatal Meningitis. J Infect Dis 214:1092-104
Scott, Caitlin E; Ahn, Kwang H; Graf, Steven T et al. (2016) Computational Prediction and Biochemical Analyses of New Inverse Agonists for the CB1 Receptor. J Chem Inf Model 56:201-12
Doran, Kelly S; Fulde, Marcus; Gratz, Nina et al. (2016) Host-pathogen interactions in bacterial meningitis. Acta Neuropathol 131:185-209
Teo, Ruijie D; Dong, Sijia S; Gross, Zeev et al. (2015) Computational predictions of corroles as a class of Hsp90 inhibitors. Mol Biosyst 11:2907-14
Krishnan, Subramanian; Chang, Alexander C; Hodges, Jacqueline et al. (2015) Serotype O18 avian pathogenic and neonatal meningitis Escherichia coli strains employ similar pathogenic strategies for the onset of meningitis. Virulence 6:777-86
Krishnan, Subramanian; Prasadarao, Nemani V (2014) 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 16:540-52
Shanmuganathan, Muthusamy V; Krishnan, Subramanian; Fu, Xiaowei et al. (2014) Escherichia coli K1 induces pterin production for enhanced expression of Fc? receptor I to invade RAW 264.7 macrophages. Microbes Infect 16:134-41

Showing the most recent 10 out of 47 publications