Deitch E A, Beck S C, Cruz N C, De Maio A
Department of Surgery, University of Medicine and Dentistry-New Jersey Medical School, Newark 07103-2714, USA.
Crit Care Med. 1995 Aug;23(8):1371-6. doi: 10.1097/00003246-199508000-00010.
The universal cellular response to stress is the expression of a family of genes known as heat shock or stress proteins. We investigated whether bacteria or bacterial products (endotoxin) can induce heat shock protein expression in human enterocytes.
Controlled, in vitro study.
Cell culture laboratory.
Human Caco-2 enterocyte cell line.
Incubation of confluent monolayers of Caco-2 cells with Escherichia coli C25 (1 x 10(9) bacteria/mL) for 1 hr at 37 degrees C was found to induce the expression of the 72-kilodalton molecular weight heat shock protein gene (heat shock protein-72), the major inducible form of the 70-kilodalton molecular weight heat shock protein family of stress proteins, as detected by Western blot analysis. The level of heat shock protein-72 induction after incubation with E. coli was similar to the response of Caco-2 cells to heat shock at 43 degrees C for 1 hr. The induction of heat shock protein-72 gene expression by E. coli was not purely due to the process of phagocytosis, since incubation of Caco-2 cells with latex beads (1 micron) failed to induce heat shock gene expression. To elucidate the possible mechanism of heat shock protein-72 induction mediated by bacteria, Caco-2 cells were incubated with E. coli endotoxin (200 micrograms/mL) for 1 hr at 37 degrees C. Such treatment was also found to induce the synthesis of heat shock protein-72.
These results demonstrate that bacteria and/or bacterial products induce the heat shock gene expression in Caco-2 cells. Since intestinal epithelial cells are constantly in contact with bacteria and bacterial products, we speculate that the heat shock gene expression may be part of the natural mechanism of protection for these cells in the potentially harmful environment that may be present in the intestinal tract.
细胞对压力的普遍反应是表达一类被称为热休克蛋白或应激蛋白的基因。我们研究了细菌或细菌产物（内毒素）是否能诱导人肠上皮细胞中热休克蛋白的表达。
对照体外研究。
细胞培养实验室。
人Caco-2肠上皮细胞系。
发现将汇合的Caco-2细胞单层与大肠杆菌C25（1×10⁹个细菌/毫升）在37℃孵育1小时，可诱导72千道尔顿分子量热休克蛋白基因（热休克蛋白-72）的表达，通过蛋白质印迹分析检测到，这是70千道尔顿分子量应激蛋白热休克蛋白家族的主要可诱导形式。与大肠杆菌孵育后热休克蛋白-72的诱导水平与Caco-2细胞在43℃热休克1小时的反应相似。大肠杆菌对热休克蛋白-72基因表达的诱导并非纯粹由于吞噬作用，因为用乳胶珠（1微米）孵育Caco-2细胞未能诱导热休克基因表达。为阐明细菌介导的热休克蛋白-72诱导的可能机制，将Caco-2细胞与大肠杆菌内毒素（200微克/毫升）在37℃孵育1小时。也发现这种处理可诱导热休克蛋白-72的合成。
这些结果表明细菌和/或细菌产物可诱导Caco-2细胞中热休克基因的表达。由于肠上皮细胞经常与细菌和细菌产物接触，我们推测热休克基因表达可能是这些细胞在肠道可能存在的潜在有害环境中自然保护机制的一部分。
