Nurmi K, Methuen T, Mäki T, Lindstedt K A, Kovanen P T, Sandler C, Eklund K K
Wihuri Research Institute, Helsinki, Finland.
Life Sci. 2009 Nov 4;85(19-20):678-84. doi: 10.1016/j.lfs.2009.09.004. Epub 2009 Sep 20.
Alcohol abuse is associated with increased frequency of infections attributed to ethanol-induced immune suppression. The precise mechanism of immune suppression is however not known. Mast cells (MC) belong to the innate immune system and they have been implicated in the first line of immune defence against bacteria and parasites. Therefore we studied the effects of ethanol and its first metabolite acetaldehyde on mast cell viability, proliferation and apoptosis.
Human mast cell line (HMC)-1 cells, mouse bone marrow derived mast cells (mBMMC) and human peripheral blood derived mast cells (HuMC) were used. Effects of ethanol and acetaldehyde on mast cell proliferation were determined by assessing incorporation of [(3)H]thymidine into cellular DNA and by trypan blue exclusion. Apoptosis was assessed by measuring apoptotic nucleosomes and caspase-3, -8 and -9 activities using ELISA and by using Tunel assay. The expression of anti- and proapoptotic proteins Bcl-2 and Bax was analyzed by RT-PCR and western blot, respectively.
Ethanol, but not acetaldehyde inhibited dose-dependently the proliferation and viability HMC-1 and mBMMC cells. The decreased viability was caused by apoptotic cell death of the MC. Significant apoptosis of HMC-1 cells was observed in the presence of 43mM (2.5 per thousand) ethanol. Induction of apoptosis was associated with clearly increased caspase-3 activity and moderately increased caspase-8 and 9 activities. Ethanol also shifted the Bcl-2/Bax balance towards apoptosis.
The ethanol-induced reduction of MC viability could contribute to immunosuppression associated with ethanol abuse.
酒精滥用与因乙醇诱导的免疫抑制导致的感染频率增加有关。然而，免疫抑制的确切机制尚不清楚。肥大细胞（MC）属于先天性免疫系统，它们参与了针对细菌和寄生虫的第一道免疫防线。因此，我们研究了乙醇及其第一种代谢产物乙醛对肥大细胞活力、增殖和凋亡的影响。
使用人肥大细胞系（HMC）-1细胞、小鼠骨髓来源的肥大细胞（mBMMC）和人外周血来源的肥大细胞（HuMC）。通过评估[（3）H]胸苷掺入细胞DNA以及台盼蓝排斥法来确定乙醇和乙醛对肥大细胞增殖的影响。通过ELISA测量凋亡核小体以及半胱天冬酶-3、-8和-9的活性，并使用Tunel检测法评估凋亡。分别通过RT-PCR和蛋白质免疫印迹分析抗凋亡和促凋亡蛋白Bcl-2和Bax的表达。
乙醇而非乙醛剂量依赖性地抑制HMC-1和mBMMC细胞的增殖和活力。活力降低是由MC的凋亡性细胞死亡引起的。在存在43mM（2.5‰）乙醇的情况下，观察到HMC-1细胞发生明显凋亡。凋亡诱导与半胱天冬酶-3活性明显增加以及半胱天冬酶-8和-9活性适度增加有关。乙醇还使Bcl-2/Bax平衡向凋亡方向转变。
乙醇诱导的MC活力降低可能导致与酒精滥用相关的免疫抑制。
