Expression data from ATRA-treated LLC-PK1 cells

We have established a role for p-ERK in mediating ATRA cytoprotection against chemical-induced injury to LLC-PK1 renal proximal tubule epithelial cells. The present studies were conducted to assess downstream signaling from p-ERK in ATRA-mediated cytoprotection. Gene expression profiling via microarray and ontology analyses indicated an upregulation of genes associated with cell proliferation and differentiation shortly after (0.5 and 1 hr) ATRA (25 μM) treatment. Target genes of these transcription factors associated with ribosome biogenesis, DNA replication, DNA repair, and the cell cycle were significantly increased by 4 hr. LLC-PK1 cells were cultured with ATRA for either 0, 0.5, 1, 4, 8, or 12 hr. Lysates were collected and total RNA was isolated and hybridized on Affymetrix microarrays. A total of 18 samples were analyzed, each sample in triplicate.