NON-CODING RNA IN ASTHMA PATHOGENESIS

Abstract

Asthma affects more than 300 million people worldwide, and 250,000 of them die each year; however, the pathogenesis of the disease has not been thoroughly investigated. Asthma is heterogeneous, chronic inflammatory airway disease characterized by episodes of dyspnea, wheezing, coughing due to airway obstruction and hyperreactivity. The inflammatory response of asthma involves many different specialized immune cells, but the most important are eosinophils. These cells are recruited to the actual site of inflammation and secrete cationic proteins, cytokines, chemokines, and lipid mediators contained in their cytoplasmic granules. It has also been found that eosinophils can release non-coding RNA (ncRNA) into the environment via their exosomes. Large quantities of ncRNA are packed in eosinophil exosomes, thereby transferring these RNAs to other cells. All RNAs that are not directly translated into the protein sequence are called ncRNAs. ncRNAs are classified as short or long, based on the number of nucleotides in their strand. The most important of the short ncRNAs are microRNA (miRNA), Piwi protein-related RNA (piRNA), and small interfering RNA (siRNA) that all inhibit the messenger RNAs translation into proteins. Long non-coding RNA (lncRNA) is another type of ncRNA that is also closely involved in the regulation of gene expression. Moreover, miRNAs and lncRNAs can interact with each other and indirectly regulate their own expression via other mediators. ncRNAs have different expression profiles depending on the cell type and disease state. One study found ncRNA is related to
the eosinophilic asthma pathogenesis, and their expression spectrum can provide useful insights to the existence of the disease. Serum ncRNA levels are stable and resistant to circulating ribonucleases. Therefore, this molecule could be a beneficial biomarker for asthma and its phenotypes and endotypes. This review present ncRNAs, focusing on the current miRNAs and lncRNAs studies, the influence of its regulated genes in asthma pathogenesis, and the relevance of these molecules for disease diagnosis.