Module 12: Figure miRNA and cardiac hypertrophy
Regulation of hypertrophy by miRNA.
Expression of the type 2 inositol 1,4,5-trisphosphate receptor (InsP3R2), calcineurin (CaN) and the nuclear factor of activated T cells 3 (NFAT3) is regulated by miR-133a. Under normal conditions, the miR-133a restrains the expression of these components. During hypertrophic stimuli that activate the InsP3R2s, there is an increase in nuclear Ca2+ that acts through serum response factor (SRF) to reduce the expression of miR-133a and this reduces its inhibitory effect on these components and results in activation of the transcriptional events that give rise to hypertrophy. For further details concerning this activation of hypertrophy see Module 12: Figure hypertrophy signalling mechanisms.