Potla Ratnakar, Singh Ishwar S, Atamas Sergei P, Hasday Jeffrey D
Pulmonary and Critical Care Medicine Division, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
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.
RNA. 2015 Jul;21(7):1261-73. doi: 10.1261/rna.049122.114. Epub 2015 May 27.
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.
先前的研究表明,临床上相关的温度变化通过转录调控改变临床上相关的基因表达谱。转录后调控的温度依赖性,特别是通过微小RNA(miRNA)的表达,研究较少。我们全面分析了在32°C或39.5°C下暴露24小时对原代培养的人小气道上皮细胞(hSAECs)中miRNA表达谱的影响及其对靶向蛋白蛋白激酶Cα(PKCα)表达的影响。使用微阵列和基于溶液杂交的nCounter分析,并通过定量逆转录-聚合酶链反应(RT-PCR)进行确认,我们发现只有五种成熟的人miRNA的表达水平存在显著的温度依赖性变化,仅占检测到的miRNA的1%。这五种miRNA中的四种是丰度较低的乘客(星)链。相对于37°C,它们在32°C时表现出相似的表达增加模式,在39.5°C时表达降低。由于PKCα mRNA对其中三种miRNA有多个潜在结合位点,我们分析了HEK 293T细胞和hSAECs中PKCα蛋白的表达。PKCα蛋白水平在32°C时最低,在39.5°C时最高,特异性miRNA抑制剂可降低这些影响。最后,我们分析了hSAECs中的细胞周期进程,发现32°C的细胞表现出最大的G1到S期转换,这一过程已知受PKCα抑制,并且特异性miRNA抑制剂可减轻这种影响。这些结果表明,暴露于临床上相关的低温或高温会改变一小部分miRNA的表达,并影响至少一种参与多个重要细胞过程的信号蛋白的表达。