甲硫氨酸脑啡肽对猴免疫缺陷病毒早期感染引起CEM x1 74细胞凋亡的可能作用(英文)

Possible Effect Pathway of Methionine Enkephalin on Apoptosis of CEM x174 Cells Induced by Simian Immunodeficiency Virus in Early Stages of Infection

探讨短期甲硫氨酸脑啡肽作用对SIV感染CEMx174细胞凋亡的可能作用 .用MTS法测定甲硫氨酸脑啡肽对感染CEMx174细胞存活率的影响 ,流式细胞仪分析SIV诱导细胞凋亡及其甲硫氨酸脑啡肽的作用 ,并测定了cAMP含量、PKA活性和组蛋白磷酸化的水平 .SIV能够显著减少CEMx174细胞数 ,甲硫氨酸脑啡肽可以提高感染细胞的存活率 .AnnexinⅤ结合实验显示 ,1μmol L甲硫氨酸脑啡肽可以增加存活细胞的比率 ,减少凋亡细胞数 .甲硫氨酸脑啡肽降低正常细胞和感染细胞cAMP的含量和PKA活性 ,但是在感染组较为明显 .在感染的情况下 ,磷酸化的组蛋白增加 ,甲硫氨酸脑啡肽可以减少其含量 .甲硫氨酸脑啡肽的作用可以被纳酪酮所拮抗 .研究结果提示 ,甲硫氨酸脑啡肽对SIV感染引起早期细胞凋亡的作用涉及cAMP

The possible mechanism of apoptosis alleviated by short term exposure of methionine enkephalin to CEM x174 cells infected with SIV was elucidated. The effects of methionine enkephalin on the viability of normal CEM x174 cells and infected cells were determined by the method of MTS assay. The apoptosis induced by SIV and the effects of methionine enkephalin were analyzed by flow cytometry. The levels of cAMP, the activities of PKA and the levels of phosphorylation of histone H3 were measured.A pronounced decrease of the cell number in SIV infected group could be noticed compared with control. Methionine enkephalin could elevate the viability of cells in infected groups. The results exhibited that Methionine enkephalin at the concentrations of 1 μmol/L could increase the percentage of vital cells and decrease the apoptotic cells based on annexin Ⅴ binding assay. Methionine enkephalin could also downregulate the content of cAMP and the activity of PKA in both groups, but more obvious in SIV infected group. The phosphorylated histone H3 was elevated in the case of virus infection and quantitatively decreased in the presence of methionine enkephalin. All effects of methionine enkephalin could be blocked by naloxone. The results indicated that cAMP PKA signal transduction cascade was involved in the regulation of methionine enkephalin on apoptosis induced by SIV during early stages.