title: Shifts in temperature within the physiologic range modify strand-specific expression of select human microRNAs.
abstract: Previous studies have revealed that clinically relevant changes in temperature modify clinically relevant gene expression profiles through transcriptional regulation. Temperature dependence of post-transcriptional regulation, specifically, through expression of miRNAs has been less studied. We comprehensively analyzed the effect of 24 h exposure to 32°C or 39.5°C on miRNA expression profile in primary cultured human small airway epithelial cells (hSAECs) and its impact on expression of a targeted protein, protein kinase C α (PKCα). Using microarray, and solution hybridization-based nCounter assays, with confirmation by quantitative RT-PCR, we found significant temperature-dependent changes in expression level of only five mature human miRNAs, representing only 1% of detected miRNAs. Four of these five miRNAs are the less abundant passenger (star) strands. They exhibited a similar pattern of increased expression at 32°C and reduced expression at 39.5°C relative to 37°C. As PKCα mRNA has multiple potential binding sites for three of these miRNAs, we analyzed PKCα protein expression in HEK 293T cells and hSAECs. PKCα protein levels were lowest at 32°C and highest at 39.5°C and specific miRNA inhibitors reduced these effects. Finally, we analyzed cell-cycle progression in hSAECs and found 32°C cells exhibited the greatest G1 to S transition, a process known to be inhibited by PKCα, and the effect was mitigated by specific miRNA inhibitors. These results demonstrate that exposure to clinically relevant hypothermia or hyperthermia modifies expression of a narrow subset of miRNAs and impacts expression of at least one signaling protein involved in multiple important cellular processes.
authors.affiliation: Pulmonary and Critical Care Medicine Division, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
authors.forename: Ratnakar
authors.initials: R
authors.lastname: Potla
authors.affiliation: Pulmonary and Critical Care Medicine Division, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA Medicine and Research Services, Baltimore VA Medical Center, Baltimore, Maryland 21201, USA.
authors.forename: Ishwar S
authors.initials: IS
authors.lastname: Singh
authors.affiliation: Medicine and Research Services, Baltimore VA Medical Center, Baltimore, Maryland 21201, USA Division of Rheumatology and Clinical Immunology, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
authors.forename: Sergei P
authors.initials: SP
authors.lastname: Atamas
authors.affiliation: Pulmonary and Critical Care Medicine Division, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA Medicine and Research Services, Baltimore VA Medical Center, Baltimore, Maryland 21201, USA jhasday@umaryland.edu.
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Hasday
mesh_terms: D006358:Hot Temperature; D006801:Humans; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D016133:Polymerase Chain Reaction
chemical_list: D035683:MicroRNAs
keywords: hyperthermia; hypothermia; lung epithelium; microRNA