Regular consumption of ethanol (EtOH) at low to moderate levels protects organs and microvasculature from the deleterious effects of ischemia and reperfusion (I/R). Recently, we discovered that antecedent ethanol ingestion provokes the development of an anti-inflammatory phenotype (reduced postischemic formation of inflammatory mediators and markedly attenuated adhesion molecule expression, oxidant production, and leukocyte rolling, adhesion, and emigration in postcapillary venules) via a novel mechanism that remains effective in the presence of co-existing risk factors for cardiovascular disease. Surprisingly, our work uncovered important roles for proinflammatory calcitonin gene-related peptide (CGRP) and tumor necrosis factor-?(TNF) mediated neutrophil activation during the period of ethanol exposure in initiating this adaptive transformation that becomes apparent in postcapillary venules when tissues are exposed to I/R 24 hrs after EtOH. In the current proposal, we seek to build on these fundamental observations to evaluate the overall hypothesis that daily moderate EtOH induces TRPV1-dependent CGRP release from sensory neurons, which in turn activates CD4+ T lymphocytes to express tumor necrosis factor-? (TNF). TNF-dependent, neutrophil proteasemediated generation of signals in the interstitium engage endothelial integrin ?v3 to induce increased HO-1 expression/activity to limit postischemic microvascular dysfunction. To address this postulate, we propose to determine the roles of: (1) EtOH-induced, CGRP-dependent activation of T lymphocytes, which subsequently produce TNF to activate tissue resident neutrophils to proteolytically generate signals that trigger the development of an anti-inflammatory phenotype in response to antecedent ethanol; and (2) neutrophil protease-initiated, ?v3 integrin-dependent increased HO-1 expression and activity as downstream mediators of the anti-inflammatory phenotype seen during I/R. Intravital microscopic approaches will be used to quantify postischemic leukocyte/endothelial cell interactions. The effects of EtOH to elevate plasma and tissue CGRP and TNF levels, induce T cell and neutrophil activation, and increase HO-1 expression and activity to prevent I/R-induced endothelial adhesion molecule and inflammatory mediator expression will also be investigated. Significance: This work will identify new links between CGRP-activated T cells, signals generated by the proteolytic activity of TNF-activated neutrophils, and ?v3-dependent HO-1 expression/activity in the acquisition of tolerance to I/R by antecedent ethanol ingestion. Completing these studies will provide the mechanistic basis for development of translational therapeutics in relevant patient populations.
Consumption of alcoholic beverages at low to moderate levels protects the heart, brain, intestine, and vasculature from the deleterious effects of ischemia (low blood flow) and reperfusion (re-establishing the blood supply) (I/R). However, the mechanisms underlying these protective actions remain unclear. The work proposed in this application will uncover the signaling pathway whereby the ethanol component of alcoholic beverages activates innate cell survival programs that culminate in the expression and increased activity of proteins that function to limit the deleterious effects of inflammation inducd by I/R. This fundamental information is required for future development of novel therapies to reduce I/R injury that mimic the remarkably powerful effects induced by ethanol ingestion, without the negative psychosocial and biochemical consequences associated with alcohol consumption.
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