Induction of heat shock gene expression in colonic epithelial cells after incubation with Escherichia coli or endotoxin.
OBJECTIVE
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.


METHODS
Controlled, in vitro study.


METHODS
Cell culture laboratory.


METHODS
Human Caco-2 enterocyte cell line.


RESULTS
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.


CONCLUSIONS
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.
Deitch
E A
EA
Department of Surgery, University of Medicine and Dentistry-New Jersey Medical School, Newark 07103-2714, USA.
Beck
S C
SC
Cruz
N C
NC
De Maio
A
A
D000230:Adenocarcinoma / Q000378:metabolism; D003106:Colon / Q000166:cytology / Q000378:metabolism*; D003110:Colonic Neoplasms / Q000378:metabolism; D004731:Endotoxins / Q000502:physiology*; D004847:Epithelial Cells; D004926:Escherichia coli / Q000502:physiology*; D005786:Gene Expression Regulation; D050884:HSP72 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000096:biosynthesis*; D006801:Humans; D010587:Phagocytosis; D013997:Time Factors; D014407:Tumor Cells, Cultured
D004731:Endotoxins; D050884:HSP72 Heat-Shock Proteins; D006360:Heat-Shock Proteins