ABSTRACT
PURPOSE: To investigate whether mild heat stress at 39.5°C altered Dicer protein and miRNA expression patterns in several cell types. METHODS: Multiple human and mouse cell types were cultured during the course of 9 h at temperatures from 37°C to 39.5°C. Dicer mRNA levels and microRNAs were quantified by TaqMan RT-qPCR assays and Dicer protein by western blotting. RESULTS: Dicer protein was substantially elevated on western analysis in response to heat stress at 39.5°C in the absence of significant changes in Dicer mRNA by RT-qPCR. CONCLUSIONS: Heat-induced regulation of Dicer expression occurs primarily post- transcriptionally, and the expression levels of Dicer protein are increased and often oscillate in response to fever-range hyperthermia in multiple mouse and human cells. Our studies suggest a potential role for Dicer and microRNAs in the response to mild thermal stress. Additional studies on the mechanisms involved in the stress-induced oscillations of Dicer protein and microRNAs will be of interest.
Subject(s)
DEAD-box RNA Helicases/metabolism , Hyperthermia, Induced , Ribonuclease III/metabolism , Animals , Cell Line , Cell Line, Tumor , Cells, Cultured , DEAD-box RNA Helicases/genetics , HSP70 Heat-Shock Proteins/genetics , HSP90 Heat-Shock Proteins/genetics , Humans , Kidney/cytology , Mice , Mice, Inbred C57BL , MicroRNAs/metabolism , RNA, Messenger/metabolism , Ribonuclease III/geneticsABSTRACT
MicroRNAs have been shown to regulate gene expression both transcriptionally and translationally. Here, we examine evidence that various stresses regulate miRNAs which, in turn, regulate immune gene levels. Multiple studies are reviewed showing altered microRNA levels in normal cells under stress and in various disease states, including cancer. Unexpected was the finding that Dicer expression is altered by treatments with several agents, such as interferons and cortisone, employed in the treatment of immune disorders. Potential signal transduction pathways, including JAK/Stat, PI3K and PKR, that may regulate Dicer and microRNA levels in normal and stressed mammalian cells are discussed.