Genome-wide posttranscriptional dysregulation by MicroRNAs in human asthma as revealed by frac-seq

RT Martinez-Nunez, H Rupani, M Platé… - The Journal of …, 2018 - journals.aai.org
RT Martinez-Nunez, H Rupani, M Platé, M Niranjan, RC Chambers, PH Howarth
The Journal of Immunology, 2018journals.aai.org
MicroRNAs are small noncoding RNAs that inhibit gene expression posttranscriptionally,
implicated in virtually all biological processes. Although the effect of individual microRNAs is
generally studied, the genome-wide role of multiple microRNAs is less investigated. We
assessed paired genome-wide expression of microRNAs with total (cytoplasmic) and
translational (polyribosome-bound) mRNA levels employing subcellular fractionation and
RNA sequencing (Frac-seq) in human primary bronchoepithelium from healthy controls and …
Abstract
MicroRNAs are small noncoding RNAs that inhibit gene expression posttranscriptionally, implicated in virtually all biological processes. Although the effect of individual microRNAs is generally studied, the genome-wide role of multiple microRNAs is less investigated. We assessed paired genome-wide expression of microRNAs with total (cytoplasmic) and translational (polyribosome-bound) mRNA levels employing subcellular fractionation and RNA sequencing (Frac-seq) in human primary bronchoepithelium from healthy controls and severe asthmatics. Severe asthma is a chronic inflammatory disease of the airways characterized by poor response to therapy. We found genes (ie, isoforms of a gene) and mRNA isoforms differentially expressed in asthma, with novel inflammatory and structural pathophysiological mechanisms related to bronchoepithelium disclosed solely by polyribosome-bound mRNAs (eg, IL1A and LTB genes or ITGA6 and ITGA2 alternatively spliced isoforms). Gene expression (ie, isoforms of a gene) and mRNA expression analysis revealed different molecular candidates and biological pathways, with differentially expressed polyribosome-bound and total mRNAs also showing little overlap. We reveal a hub of six dysregulated microRNAs accounting for∼ 90% of all microRNA targeting, displaying preference for polyribosome-bound mRNAs. Transfection of this hub in bronchial epithelial cells from healthy donors mimicked asthma characteristics. Our work demonstrates extensive posttranscriptional gene dysregulation in human asthma, in which microRNAs play a central role, illustrating the feasibility and importance of assessing posttranscriptional gene expression when investigating human disease.
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