Alcohol consumption is associated with increased susceptibility to infections and impaired immune responses, the mechanisms if which are not well understood. LPS, a major component of bacterial wall, is recognized by toll-like receptor (TLR) 4 and ? accessory molecule CD14 and triggers a variety of intracellular events that culminates in the production of pro-inflammatory cytokines. Our previous work showed that in monocytes, acute alcohol impairs bacterial lipopolysaccharide (LPS)-induced cellular activation via inhibition of NF?B pathway to result in low pro-inflammatory cytokines production. Recent studies suggest that LPS triggers formation of a large """"""""signalosome"""""""" - a complex of cellular receptors, including TLR4, CD14, FcR, CD36, CD55, CD11b, CD18, Hsp70, Hsp90, and CXCR4. Formation of signalosome requires rigid cholesterolrich membrane platforms, called membrane rafts. We recently identified that disruption of membrane rafts via cholesterol depletion prevents LPS-induced cell activation. Further, we identified that alcohol prevents TLR4 association with rafts. Based on preliminary data, we hypothesize that alcohol may affect the early events of LPStriggered cell activation. We postulate that inhibition cell activation by alcohol depends on the complexity of signal events that take place at the level of membrane rafts. We further hypothesized that acute alcohol targets the LPS-triggered recruitment of signalosome into lipid rafts and thus prevents cell activation. Specifically, we propose that alcohol disrupts the formation of the """"""""signalosome"""""""".
The Specific Aim of this proposal is to determine the influence of alcohol on the integrity of the TLR4 receptor complex (TLR4, CD14, MD2, MyD88, signalosome members) A) by exploring the colocalization with membrane rafts; B) evaluating the association with detergent-resistant membranes (DRMs); C) detecting acquisition/loss of proteins within the TLR4 receptor complex D) studying the formation of TLR4 multimers. Results from these studies should delineate the early molecular events that lead to impaired LPS-induced cellular activation after acute exposure to alcohol. Investigation of the early steps of LPS signaling may identify strategies for interfering with the effects of LPS and design therapeutic approaches for improving immunity against infections. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute on Alcohol Abuse and Alcoholism (NIAAA)
Type
Exploratory/Developmental Grants (R21)
Project #
5R21AA016571-02
Application #
7498553
Study Section
Health Services Research Review Subcommittee (AA)
Program Officer
Jung, Kathy
Project Start
2007-09-20
Project End
2010-08-31
Budget Start
2008-09-01
Budget End
2010-08-31
Support Year
2
Fiscal Year
2008
Total Cost
$192,969
Indirect Cost
Name
University of Massachusetts Medical School Worcester
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
603847393
City
Worcester
State
MA
Country
United States
Zip Code
01655
Dolganiuc, Angela; Thomes, Paul G; Ding, Wen-Xing et al. (2012) Autophagy in alcohol-induced liver diseases. Alcohol Clin Exp Res 36:1301-8
Dolganiuc, Angela (2011) Role of lipid rafts in liver health and disease. World J Gastroenterol 17:2520-35
Dolganiuc, Angela; Szabo, Gyongyi (2009) In vitro and in vivo models of acute alcohol exposure. World J Gastroenterol 15:1168-77
Szabo, Gyongyi; Dolganiuc, Angela (2008) Hepatitis C and innate immunity: recent advances. Clin Liver Dis 12:675-92, x
Dolganiuc, Angela; Szabo, Gyongyi (2008) T cells with regulatory activity in hepatitis C virus infection: what we know and what we don't. J Leukoc Biol 84:614-22