Islet microRNAs in health and type-2 diabetes

Failure of the beta-cell to secrete enough insulin is a major contributing factor in the pathogenesis of type-2 diabetes (T2D). MicroRNAs provide an extra layer in the regulation of protein expression, and are thus involved in beta-cell compensation during development of the disease. In this review, we discuss how microRNAs can regulate their target protein expression and phenotypic output, present the status of nutritional regulation of microRNA expression, and summarize work on microRNA expression in human islets. In conclusion, current data lend support to microRNAs being essential regulators of insulin secretion. Future work will describe microRNAs in alpha-cell function, details of the microRNA mRNA network, and possibilities to use microRNAs as biomarkers and in therapeutic treatment of T2D and complications.