Norkina Oxana, Dolganiuc Angela, Catalano Donna, Kodys Karen, Mandrekar Pranoti, Syed Amber, Efros Marian, Szabo Gyongyi
Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
Alcohol Clin Exp Res. 2008 Sep;32(9):1565-73. doi: 10.1111/j.1530-0277.2008.00726.x. Epub 2008 Jul 9.
Acute alcohol consumption is associated with induction of immuno-inhibitory cytokines and down-regulation of pro-inflammatory responses to various pathogens. We previously reported that alcohol activates janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling leading to IL-10 induction. The JAK-STAT pathway also activates its own negative regulators, suppressors of cytokine signaling (SOCS) 1 and SOCS3. SOCS proteins are inducible inhibitors that negatively regulate STAT3/STAT1 signaling pathways induced by cytokines, IL-6 or IFNs. Here we aimed to explore the effect of acute alcohol on induction of SOCS1/SOCS3 and regulation of STAT3/STAT1 pathways induced by IL-6 or IFNs in human monocytes.
Blood samples from normal volunteers were collected before and 24 hours after consumption of 2 ml vodka/kg body weight. For in vitro experiments human monocytes were pretreated with ethanol (EtOH) followed by stimulation with cytokines; proteins were analyzed by Western blot, nuclear protein binding to DNA by EMSA, and RNA by real time PCR.
Acute in vivo or in vitro alcohol treatment increased both SOCS1 and SOCS3 RNA expression in monocytes. Alcohol treatment resulted in increased STAT3 and STAT1 DNA binding capacity. Activation of both STAT1 and STAT3 has been shown to induce SOCS1/3. We hypothesized that induction of SOCS proteins by alcohol in turn may lead to modulation of cytokine signaling through STAT1 and STAT3. Indeed, we observed significant down-regulation of IL-6-, IFNalpha- and IFNgamma-induced STAT1 DNA binding as well as inhibition of IL-6- and IFNgamma-induced STAT3 when alcohol was added to monocytes 3 hours prior to the cytokine stimulation. Consistent with inhibition of IL-6-induced STAT3 DNA binding in alcohol-pretreated cells, the levels of IL-6-dependent genes, MCP-1 and ICAM-1, was reduced after IL-6 stimulation. Similar to EtOH alone, combined EtOH+IL-6 simulation resulted in increased expression of both SOCS3 and SOCS1 genes.
While acute alcohol treatment alone activates STAT1/3 signaling pathways and induces SOCS3 and SOCS1 levels in monocytes, alcohol also leads to down-regulation of IL-6-, IFNalpha-, and IFNgamma-induced signaling via STAT1/STAT3 pathways, likely through excessive SOCS activation.
急性酒精摄入与免疫抑制细胞因子的诱导及对各种病原体促炎反应的下调有关。我们之前报道过酒精激活janus激酶/信号转导子和转录激活子（JAK/STAT）信号通路导致白细胞介素-10（IL-10）的诱导。JAK-STAT通路也会激活其自身的负调节因子，即细胞因子信号抑制因子（SOCS）1和SOCS3。SOCS蛋白是可诱导的抑制剂，可负调节由细胞因子、IL-6或干扰素诱导的STAT3/STAT1信号通路。在此，我们旨在探讨急性酒精对人单核细胞中SOCS1/SOCS3诱导以及IL-6或干扰素诱导的STAT3/STAT1通路调节的影响。
收集正常志愿者在饮用2毫升/千克体重伏特加之前及之后24小时的血样。对于体外实验，人单核细胞先用乙醇（EtOH）预处理，然后用细胞因子刺激；通过蛋白质印迹法分析蛋白质，通过电泳迁移率变动分析（EMSA）检测核蛋白与DNA的结合，通过实时聚合酶链反应（PCR）检测RNA。
急性体内或体外酒精处理均增加了单核细胞中SOCS1和SOCS3的RNA表达。酒精处理导致STAT3和STAT1的DNA结合能力增强。已证明STAT1和STAT3的激活均会诱导SOCS1/3。我们推测酒精诱导的SOCS蛋白反过来可能会通过STAT1和STAT3调节细胞因子信号传导。事实上，当在细胞因子刺激前3小时向单核细胞中加入酒精时，我们观察到IL-6、干扰素α和干扰素γ诱导的STAT1 DNA结合显著下调，以及IL-6和干扰素γ诱导的STAT3受到抑制。与酒精预处理细胞中IL-6诱导的STAT3 DNA结合受到抑制一致，IL-6刺激后，IL-6依赖性基因单核细胞趋化蛋白-1（MCP-1）和细胞间黏附分子-1（ICAM-1）的水平降低。与单独使用EtOH类似，EtOH与IL-6联合刺激导致SOCS3和SOCS1基因的表达均增加。
虽然单独的急性酒精处理会激活单核细胞中的STAT1/3信号通路并诱导SOCS3和SOCS1水平，但酒精也会导致通过STAT1/STAT3通路介导的IL-6、干扰素α和干扰素γ诱导的信号传导下调，这可能是由于SOCS过度激活所致。
