Identifying Expression of Circular RNA in Cardiac Fibroblasts and Cardiac Myocytes

• Trevor Burleigh, Applied Molecular Biology & Biotechnology, University of Delaware

• Mona Batish, Medical and Molecular Sciences, University of Delaware

Cardiovascular diseases are a major health burden. The most commonly used drugs include tyrosine kinases inhibitors (TKI) that work by blocking ATP pathways disrupting proliferation and Proteosome inhibitors work to inhibit proteasomes to destroy cell proliferation proteins. Four inhibitors have been found to affect the expression of circular RNAs within cardiac fibroblasts and myocytes. We are interested in identifying the effect of these inhibitors on a newly identified class of regulatory RNAs called circular RNAs (circRNA). CircRNAs play an important role in acting as transcriptional regulators, microRNA sponges, biomarkers,  and they can play a role in cell to cell communication and be used as therapeutic targets.

Expression level of 5 different circular RNAs identified through previous literature was analyzed in RNA isolated from cardiac fibroblast and cardiomyocyte cells treated with different concentrations of inhibitor added. RNA was isolated using Trizol extraction method and then converted to cDNA using iscript reverse transcriptase kit. The cDNA was used for the qRT-PCR reaction. The expression for 18S RNA was used as a housekeeping normalization control. Agarose gel electrophoresis was then used to confirm the size of the amplicon

In the study, it was found that circNFIX RNA expression was increased as the concentration of inhibitor was increased in cardiac fibroblasts by using qRT-PCR. The expression of circZNF609 and circHIPK3 was downregulated as the concentration of inhibitor increased. In cardiac myocytes, circRNAs expression is dysregulated after treatment, with expressions varying.

Upregulation of circNFIX in cardiac fibroblasts when treated with a TKI allows for further indication that these treatments may be a potential therapeutic in patients that need to repress the proliferation of cardiac cells by increasing circular RNA expression. CircZNF609 and CircHIPK3 were downregulated when treated with inhibitors and could be used to create a treatment that promotes the proliferation of cardiac cells and causes attenuated cell death. Future studies include exploring more circular RNA and conducting more research on how these drugs affect cardiac cells.