Integrated MicroRNA–mRNA Sequencing Analysis Identifies Regulators and Networks Involved in Feline Hypertrophic Cardiomyopathy

Cardiac remodeling in feline hypertrophic cardiomyopathy (HCM) is poorly understood. To investigate underlying molecular mechanisms, we determined microRNA–mRNA interactions, regulatory networks, and upstream regulators using left ventricle (LV) and left atrium (LA) mRNA and microRNA sequencing datasets from cats with HCM and controls. Upstream regulators, molecules, and pathways associated with ischemia, inflammation, fibrosis, and cellular changes were observed in the HCM heart. In both the HCM LV and LA, TNFα, IL1β, and TGFβ were identified as upstream regulators, along with FGF23, THBS4, and FAMB177 as the top increased molecules. Relevant microRNAs included upstream regulator miR-132, enriched miR-124-3p, miR-122b-3p, miR-146-5p (HCM LV and LA), miR-370, miR-1185-5p, miR-12194-3p (HCM LV), miR-153-3p, miR-185-5p, and miR-185-3p (HCM LA). Macrophage pathways were activated, and granulocyte and agranulocyte adhesion and diapedesis were the most connected pathways. The HIF1α signaling pathway in the HCM LV, upstream regulators miR-1-3p and miR-204, and reduced miR-29 and miR-122-5p suggest cardioprotective mechanisms. Observed in the healthy heart and suspected to be involved in cardiac homeostasis were upstream regulators miR-96, inhibited WNT3A and miR-145, as well as miR-140-5p, miR-141-3p, miR-208b-3p, and miR-885-3p. This study provides further insights into the pathogenesis of HCM, and identifies the factors involved in the maintenance of a healthy LV and LA.