MicroRNA expression in the heart of Xenopus laevis facilitates metabolic adaptation to dehydration

Xenopus laevis survive severe dehydration during the summer months in their natural range. MicroRNA regulate translation of target mRNAs and have shown to be differentially expressed in response to dehydration in X. laevis. During dehydration, heart rate is elevated which appears to compensate for the reduced oxygen delivery capability due to increased hematocrit. We hypothesized that microRNAs would be differentially expressed in the heart to modulate gene expression levels in response to dehydration. The present study assessed changes in the microRNAome of X. laevis heart in response to severe dehydration (30% loss of body water) using microRNA-seq. We show that target genes are enriched for RNA, DNA, and transcription factor binding activities, cardiac muscle contraction, and glycolysis/gluconeogenesis. These results suggest that microRNAs contribute to gene expression reorganization in the heart in response to dehydration, putatively supporting the increased physiological demands and ATP production needs by the heart under these conditions.