Upregulation of eIF6 inhibits cardiac hypertrophy induced by phenylephrine

Cardiac hypertrophy is determined by an increase of cell size in cardiomyocytes (CMCs). Among thecellular processes regulating the growth of cell size, the increase of protein synthesis rate represents acritical event. Most of translational factors promoting protein synthesis stimulate cardiac hypertrophy. Incontrast, activity of translational repressor factors, in cardiac hypertrophy, is not fully determined yet.Here we report the effect of a translational modulator, eIF6/p27BBPin the hypertrophy of neonatal ratCMCs. The increase of eIF6 levels surprisingly prevent the growth of cell size induced by phenylephrine,through a block of protein synthesis without affecting skeletal rearrangement and ANF mRNA expression.Thus, this work uncovers a new translational cardiac regulator independent by other well-known factorssuch as mTOR signalling or eIF2b.