This project intends to develop a new paradigm for the known in vivo immunosuppressive effects induced by alcohol ingestion. Carried out in consortium collaboration with Dr. Louis Lange, the proposed investigations will explore the immunological implications of the esterification of ethanol with essential polyunsaturated fatty acids, via fatty acid ethyl ester (FAEE) synthase activity, that induces the depletion and/or redirection of linoleate and arachidonate from intracellular lipid pools. Diet-induced essential fatty acid deficiency inhibits monocyte influx into kidney, lung, and skin in various models of inflammation and part of its immunosuppressive effects is attributable to the inhibited release of a recently described lipid monocyte-specific chemotactic factor. Alcohol ingestion is similarly associated with inhibited monocyte influx in inflammation of the lung and kidney, depletion of arachidonate from tissue, and inhibited release of the lipid chemotaxin into nephritic urine. This project utilizes a model of glomerulonephritis preceded by short-term alcohol ingestion to establish quantitative correlations between quantity of alcohol consumed, inhibition of monocyte influx into the glomerulus, and renal content of fatty acid ethyl esters. The effects of alcohol on renal function, epithelial transport, and integrity of glomerular basement membrane will be assessed in the context of inhibition of the monocyte- dependent, chronic phase of glomerulonephritis. FAEE synthase activity, recently localized to the kidney, will be assayed with and without prior ethanol exposure, under normal and inflammatory conditions. The enzyme(s) will be isolated, purified, and compared to enzymes identified in the heart and liver. Transfection of renal cell lines with previously cloned FAEE synthase will be undertaken to confirm the association between arachidonate/linoleate depletion and inhibited release of the monocyte chemotaxin. Release of this factor will be directly assayed by chromatographic techniques in renal tissue and cell lines exposed to alcohol in vivo and in vitro. Reversal of the alcohol-induced EFA- deficient state will be undertaken via repletion with esterified forms of linoleate. Finally, the potential inhibitory effects of fatty acid ethyl esters on monocyte responsiveness to chemotactic signals will be evaluated. Investigating the metabolic effects of alcohol on lipid-dependent signaling between non-immune cells and monocytes should allow potential therapeutic strategies to reduce the susceptibility of alcoholics to infections.
