Acute alcohol exposure exerts anti-inflammatory effects by inhibiting IκB kinase activity and p65 phosphorylation in human monocytes

Acute alcohol use is associated with impaired immune responses and decreased proinflammatory cytokine production. Our earlier studies have shown that acute alcohol intake inhibits NF-kappa B DNA binding in an I kappa Ba-independent manner. We report using human peripheral blood monocytes and Chinese hamster ovary cells transfected with CD14 cells that acute alcohol treatment in vitro exerts NF-kappa B inhibition by disrupting phosphorylation of p65. Immunoprecipitation of p65 and I kappa Ba revealed that acute alcohol exposure for 1 h decreased NF-kappa B-I kappa B alpha complexes in the cytoplasm. Phosphorylation of p65 at Ser 516 is mediated by I kappa B kinase (IKK)beta and is required for NF-kappa B-dependent cellular responses. We show that acute alcohol treatment decreased LPS-induced IKK alpha and IKK beta activity resulting in decreased phosphorylation of p65 at Ser(536). Furthermore, nuclear expression of IKKa increased after alcohol treatment, which may contribute to inhibition of NF-KB.. Decreased phosphorylation of nuclear p65 at Ser 276 was likely not due to alcohol-induced inhibition of protein kinase A and mitogen- and stress-activated protein kinase-1 activity. Although decreased I kappa B alpha phosphorylation after acute alcohol treatment was attributable to reduced IKK)3 activity, degradation of I kappa B alpha during alcohol exposure was IKK beta-independent. Alcohol-induced degradation of I kappa Ba in the presence of a 26S proteasome inhibitor suggested proteasome-independent I kappa B alpha degradation. Collectively, our studies suggest that acute alcohol exposure modulates I kappa B alpha-independent NF-kappa B activity primarily by affecting phosphorylation of p65. These findings further implicate an important role for IKK beta in the acute effects of alcohol in immune cells.