title: Reduced immune cell infiltration and increased pro-inflammatory mediators in the brain of Type 2 diabetic mouse model infected with West Nile virus.
abstract: BACKGROUND
  Diabetes is a significant risk factor for developing West Nile virus (WNV)-associated encephalitis (WNVE) in humans, the leading cause of arboviral encephalitis in the United States. Using a diabetic mouse model (db/db), we recently demonstrated that diabetes enhanced WNV replication and the susceptibility of mice to WNVE. Herein, we have examined immunological events in the brain of wild type (WT) and db/db mice after WNV infection. We hypothesized that WNV-induced migration of protective leukocytes into the brain is attenuated in the presence of diabetes, leading to a high viral load in the brain and severe disease in diabetic mice.
  
  
  METHODS
  Nine-week old C57BL/6 WT and db/db mice were infected with WNV. Leukocyte infiltration, expression of cell adhesion molecules (CAM), neuroinflammatory responses, activation of astrocytes, and neuronal death were analyzed using immunohistochemistry, qRT-PCR, flow cytometry, and western blot.
  
  
  RESULTS
  We demonstrate that infiltration of CD45+ leukocytes and CD8+T cells was significantly reduced in the brains of db/db mice, which was correlated with attenuated expression of CAM such as E-selectin and ICAM-1. WNV infection in db/db mice was associated with an enhanced inflammatory response in the brain. mRNA and protein levels of key chemokines such as CXCL10, CXCL1, CCL2, CCL5, CCL3, and G-CSF, and cytokines such as IL-1β, TNF, IL-6, IFNγ, and IL-1α were significantly elevated in the brains of db/db mice compared to WT mice. Elevated levels of cytokines also correlated with increased astrocytes activation and neuronal damage in the brains of db/db mice.
  
  
  CONCLUSIONS
  These data suggest that reduced leukocytes recruitment, in part, due to lower levels of CAM results in failure to clear WNV infection from the brain leading to increased production of inflammatory molecules, which mediates increased neuronal death and mortality in db/db mice. This is the first study to elucidate the expression of CAM and their correlation with the migration of leukocytes, specifically cytotoxic CD8+ T cells, in increasing disease severity in the diabetic mouse model.
authors.forename: Mukesh
authors.initials: M
authors.lastname: Kumar
authors.forename: Kelsey
authors.initials: K
authors.lastname: Roe
authors.forename: Pratibha V
authors.initials: PV
authors.lastname: Nerurkar
authors.forename: Beverly
authors.initials: B
authors.lastname: Orillo
authors.forename: Karen S
authors.initials: KS
authors.lastname: Thompson
authors.forename: Saguna
authors.initials: S
authors.lastname: Verma
authors.affiliation: Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A, Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, BSB 320G, Honolulu, Hawaii 96813, USA. nerurkar@hawaii.edu.
authors.forename: Vivek R
authors.initials: VR
authors.lastname: Nerurkar
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D001921:Brain / Q000473:pathology* / Q000503:physiopathology; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism; D002465:Cell Movement / Q000502:physiology; D016207:Cytokines / Q000235:genetics / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000235:genetics / Q000473:pathology*; D004195:Disease Models, Animal; D005786:Gene Expression Regulation; D007962:Leukocytes / Q000378:metabolism / Q000473:pathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000473:pathology; D054411:Receptors, Leptin / Q000235:genetics / Q000378:metabolism; D013154:Spleen / Q000473:pathology; D014901:West Nile Fever / Q000150:complications / Q000473:pathology*; D014902:West Nile virus / Q000472:pathogenicity*
chemical_list: D015703:Antigens, CD; D015815:Cell Adhesion Molecules; D016207:Cytokines; D009419:Nerve Tissue Proteins; D054411:Receptors, Leptin; C515447:leptin receptor, mouse
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