Back to Search
Start Over
Cadmium Induces the Expression of Grp78, an Endoplasmic Reticulum Molecular Chaperone, in LLC-PK1 Renal Epithelial Cells
- Source :
- Environmental Health Perspectives
- Publication Year :
- 2006
- Publisher :
- Environmental Health Perspectives, 2006.
-
Abstract
- To reveal the effects of cadmium exposure on the endoplasmic reticulum (ER) stress response, we examined the expression and function of 78-kDa glucose-regulated protein (Grp78) , an ER-resident molecular chaperone, in LLC-PK1 cells. In cells treated with 10 microM cadmium chloride, Grp78 protein levels increased after 6 hr and remained elevated at 24 hr. When cells were incubated with 1-20 microM CdCl2 for 6 hr, Grp78 increased in a dose-dependent manner. In addition, Grp78 mRNA levels were elevated in response to CdCl2 exposure. After exposure to 10 microM CdCl2, the levels of activating transcription factor 4 (ATF4) were increased at 2 hr, with a further enhancement after that ; this accumulation followed the transient but marked phosphorylation of the alpha subunit of eukaryotic translation initiation factor 2 (eIF2(alpha)) on serine 51. Although ATF4 mRNA levels increased mildly by CdCl2 exposure, treatment with actinomycin D did not suppress CdCl2-induced accumulation of ATF4 protein, suggesting the involvement of posttranscriptional and, in part, transcriptional mechanisms. Compared with other heavy-metal compounds such as manganese chloride, zinc chloride, mercuric chloride, and lead chloride, CdCl2 could increase the levels of Grp78, ATF4, and the phosphorylated form of eIF2(alpha) more markedly without definite cellular damage. The silencing of Grp78 expression using short-interference RNA enhanced CdCl2-induced cellular damage. These results show that cadmium induces the expression of Grp78 probably via phosphorylation of eIF2(alpha) and resultant translation of ATF4, and this ER stress response plays a role in protection against cadmium cytotoxicity in this renal epithelial cell.
- Subjects :
- inorganic chemicals
cadmium
Health, Toxicology and Mutagenesis
Blotting, Western
Eukaryotic Initiation Factor-2
eIF2α
Cadmium chloride
Biology
Kidney
chemistry.chemical_compound
Heat shock protein
Animals
ATF4
RNA Processing, Post-Transcriptional
Endoplasmic Reticulum Chaperone BiP
Heat-Shock Proteins
DNA Primers
G alpha subunit
Regulation of gene expression
eIF2
Base Sequence
Reverse Transcriptase Polymerase Chain Reaction
Research
Endoplasmic reticulum
Public Health, Environmental and Occupational Health
Epithelial Cells
heavy metal
Activating Transcription Factor 4
Molecular biology
Grp78
Gene Expression Regulation
chemistry
siRNA
endoplasmic reticulum stress
LLC-PK1 Cells
Phosphorylation
Molecular Chaperones
Subjects
Details
- ISSN :
- 15529924 and 00916765
- Volume :
- 114
- Database :
- OpenAIRE
- Journal :
- Environmental Health Perspectives
- Accession number :
- edsair.doi.dedup.....e97baf7bea0796cc8cd840e8102e172d