Studies on mechanism for Initial Responses to Stress in Cells

先前，我们发现热休克应激可迅速诱导人成纤维细胞中的甾基糖苷(SG)，并假设SG在细胞应激反应过程中起着重要的脂质介质的作用。在本研究中，我们研究了SG对冷束缚应激致大鼠胃溃疡的保护作用。(1)冷束缚应激诱导胃和肾脏组织中胆固醇基葡萄糖苷(CG)的器官特异性蓄积。(2)在大鼠胃匀浆中检测到CG的生物合成酶活性。该酶是一种膜结合的葡萄糖转移酶，以UDP-葡萄糖和胆固醇为底物。(3)应激前灌胃给予CG，大鼠胃溃疡的形成明显受到抑制。灌胃给予CG后，HSFL迅速激活，HSP70在胃粘膜细胞中迅速表达。(4)尽管没有观察到HSP的诱导，但口服大豆提取物SG也有抗溃疡作用。这些结果表明，CG可能在应激信号转导系统的早期阶段起到脂质介质的作用，SGS是治疗胃溃疡的有效细胞保护剂。

Previously, we found that heat shock stress rapidly induced sterylglucoside(SG) in human fibroblast cells and hypothesized that SG functions as a crucial lipid mediator in the process of cellular stress responses. In this study, we examined the protective effect of SG against cold-restraint stress-induced gastric ulcer in rats.(1)It was shown that cold-restraint stress induced the organ-specific accumulation of cholesterylglucoside(CG) in stomach and kidney.(2)A biosynthetic enzyme activity of CG was detected in homogenates of rat stomach. The enzyme was a membrane-bound glucosyltransferase, which uses UDP-glucose and cholesterol as substrates.(3)When CG was orally administered to rat prior to the stress application, the formation of gastric ulcer was markedly suppressed as compared to control. Orally administered CG caused the rapid activation of HSFl and the subsequent expression of HSP70 in gastric mucous cells.(4)Oral administration of SG derived from soy bean also showed the untiulcer effect, although no HSP induction was observed.These findings suggest that CG may act as a lipid mediator in an early stage of the stress signal transduction system and that SGs are effective cytoprotective agents for medical treatment of gastric ulcer.