Anticipatory Biogenesis of Hepatic Fed MicroRNAs is Regulated by Metabolic and Circadian Inputs

Abstract

Starvation and refeeding are mostly unanticipated in the wild in terms of duration, frequency, and nutritional value of the refed state. Notwithstanding this, organisms mount efficient and reproducible responses to restore metabolic homeostasis. Hence, it is intuitive to invoke expectant molecular mechanisms that build anticipatory responses to enable physiological toggling during fed-fast cycles. In this regard, we report anticipatory biogenesis of oscillatory hepatic microRNAs, which were earlier shown to peak during a fed state to inhibit starvation-responsive genes. Results presented in this study clearly demonstrate that the levels of primary and precursor microRNA transcripts increase during a fasting state, in anticipation of a fed response. We delineate the importance of both metabolic inputs and circadian cues in orchestrating microRNA homeostasis in a physiological setting, using the most prominent hepatic fed-miRNAs as candidates. Besides illustrating the metabo-endocrine control, our findings provide a mechanistic basis for the overarching influence of starvation on anticipatory biogenesis. Importantly, by employing pharmacological agents that are widely used in the clinics, we point out the high potential of interventions to restore homeostasis of hepatic microRNAs, whose deregulated expression is otherwise well established to cause metabolic diseases.