Establishing an in vitro condition to study the functional relevance of cardiac-specific micrornas

Ischemic heart disease is a leading cause of mortality among individuals with Type 2 diabetes. Since their discovery in 1993, microRNAs (miRs) are described to be short non-coding RNAs that post-transcriptionally regulate the gene expression of numerous processes including the development of the heart and vascular system. Consequently, miRs are able to control multiple cellular functions i.e. apoptosis, necrosis, cell proliferation and differentiation under both physiological and pathophysiological conditions. Although several miRs show a dynamic regulation in human heart disease, the expression level of cardiac-specific miR-1 is largely altered during cardiovascular injury. Therefore, the aim of this project was to establish an optimal in vitro condition to investigate the functional relevance of cardiac-specific miR-1 in hyperglycaemic and hypoxic conditions. The first objective of this study was to validate the expression of cardiac-specific miR-1 in human cardiomyocytes from non-diabetic and Type 2 diabetic patients with IHD. Results from this study showed a significant upregulation of miR-1 in right atrial appendage cardiomyocytes from Type 2 diabetic patients with ischaemic heart disease compared to non-diabetics. The second objective of this study was to establish an optimal in vitro condition to study the functional relevance of miR-1 under hyperglycaemic and hypoxic conditions. Despite the numerous trials involved in establishing the AC16 cells under these conditions, we were unable to show the modulation of cardiac-specific miR-1 in the cardiomyocytes when exposed to normoxic and/or hypoxic high glucose treatment. Although these results are preliminary, they suggest that AC16 cells are not a good model to study the functional relevance and therapeutic modulation of cardiac-specific miRs in vitro