Evaluation of expression levels of microRNA processing elements in patients with sudden sensorineural hearing loss

Abstract

MicroRNAs have a significant role in the function and development of the hearing system. Idiopathic sudden sensorineural hearing loss (SSNHL) is a complicated disorder with no long-established reason. Since microRNAs play imperative roles in every aspect of the neural system, their dysregulation may contribute to the onset of SSNHL. The current study aimed to assess the expression patterns of microRNA processing elements (DROSHA, DICER, and DGCR-8) as the vital factors in microRNA biology that can affect the expression levels of microRNA. This study assessed DROSHA, DICER, and DGCR-8 mRNA expression levels in the peripheral blood mononuclear cells (PBMC) of 50 patients with SSNHL and 50 matched controls. After the isolation of PBMC, total RNA was extracted, and the expression levels of DROSHA, DICER, and DGCR-8 genes were evaluated using quantitative real-time PCR. The results illustrated significant up-regulation of DICER and DGCR-8 genes in SSNHL patients at the mRNA level. Furthermore, despite no significant change in DROSHA level, DICER and DGCR-8 were significantly correlated with SSNHL. However, there was no significant correlation between these gene expressions and the clinicopathological features of patients. This study verified for the first time that the DGCR_8 and DICER mRNA expression levels were significantly up-regulated in patients with SSNHL, proposing that microRNAs and their processing pathways play key roles in the progression and development of SSNHL.