E-GEOD-51454 - The NRF2-KEAP1 pathway is an early responsive gene network in arsenic exposed lymphoblastoid cells

Status
Released on 24 October 2013, last updated on 4 November 2013
Organism
Homo sapiens
Samples (9)
Array (1)
Protocols (7)
Description
Inorganic arsenic, a major environmental contaminant, has risen as an important health problem worldwide. More detailed identification of the molecular mechanisms associated with iAs exposure would help to establish better strategies for prevention and treatment. Although chronic iAs exposures have been previously studied there is little to no information regarding the early events of exposure to iAs. To better characterize the early mechanisms of iAs exposure we conducted gene expression studies using sublethal doses of iAs at two different time-points. The major transcripts differentially regulated at 2 hrs of iAs exposure included antioxidants, detoxificants and chaperones. Moreover, after 12 hrs of exposure many of the down-regulated genes were associated with DNA replication and S phase cell cycle progression. Interestingly, the most affected biological pathway by both 2 or 12 hrs of iAs exposure were the Nrf2-Keap1 pathway, represented by the highly up-regulated HMOX1 transcript, which is transcriptionally regulated by the transcription factor Nrf2. Additional Nrf2 targets included SQSTM1 and ABCB6, which were not previously associated with acute iAs exposure. Signalling pathways such as interferon, B cell receptor and AhR route were also responsive to acute iAs exposure. Since HMOX1 expression increased early (20 min) and was responsive to low iAs concentrations (0.1 M), this gene could be a suitable early biomarker for iAs exposure. In addition, the novel Nrf2 targets SQSTM1 and ABCB6 could play an important and previously unrecognized role in cellular protection against iAs We used human lymphoblastoid cell line (CL-1), immortalized with Epstein-Barr virus. Cell cultures were propagated in RPMI media supplemented with 10% fetal bovine serum (FBS), L-glutammine 2 mM and antiobiotics penicillin and 10 mg/ml streptomycin) at 37ºC in an atmosphere of 5% CO2. In the case of primary cultures, 1% phytohemaglutinine were added. Cell cultures (1x106) were treated with 5µM sodium arsenite for 2 and 12 hrs while control cultures were incubated with PBS. Nine biological replicates for each condition were used for microarray analysis. After iAs treatment, total RNA from each biological replicate was isolated with Trizol. From the 9 biological replicates performed on each condition, we generated 3 pools at a concentration of 300 ng/µL, where each pool was processed to a single microarray platform.
Experiment type
transcription profiling by array 
Contacts
Angelica Martinez <amartinez@inmegen.gob.mx>, Angelica Martinez-H, Emilio J Cordova
MIAME
PlatformsProtocolsVariablesProcessedRaw
Files
Investigation descriptionE-GEOD-51454.idf.txt
Sample and data relationshipE-GEOD-51454.sdrf.txt
Raw data (1)E-GEOD-51454.raw.1.zip
Processed data (1)E-GEOD-51454.processed.1.zip
Array designA-AFFY-141.adf.txt
Links