miRNA Expression Profiles in Isolated Ventricular Cardiomyocytes: Insights into Doxorubicin-Induced Cardiotoxicity

Doxorubicin (DOX) is a first-line chemotherapeutic agent widely used in the treatment of various cancers, but its clinical efficacy is limited by its early and late cardiotoxic effects. Prior to the visible morphological manifestation of lesions in cardiomyocytes after exposure to DOX, they can detect damage and initiate a complex cascade of responses, including the modulation of gene expression, including the regulation of microRNAs (miRNAs).In this study, we used small RNA sequencing to evaluate miRNA expression levels in cardiomyocytes exposed to DOX at a concentration of 10 μM for periods of 1 and 22 hours, compared to unexposed cells. By analyzing the normalized data and using DESeq2, we identified significant changes in the expression of certain miRNAs in DOX-treated cells. These miRNAs emerge as promising biomarker candidates that, if further investigated, could provide a valuable early detection tool for DOX sensitivity and guide the timely administration of cardioprotective agents. Ventricular cardiomyocytes were isolated from adult female Hartley guinea pigs using the Langendorff retrograde perfusion system and enzymatic dissociation. These cardiomyocytes were exposed to 10 μM DOX and incubated at room temperature for 1 and 22 hours. Total RNA was extracted with Trizol reagent and quantified by spectrophotometry. Small RNA sequencing was performed using Illumina technology, and RNA quality was assessed using the RNA integrity parameter (RIN). A library of small RNAs was constructed using the TruSeq kit and sequenced on a HiSeq 2500. Reads were aligned to the Homo sapiens reference genome and miRNAs were identified from the sequencing data using miRDeep.