Cardiac Aquaporin-1: a new regulator of myocardial remodeling.
cardiovascular diseases • physiology • molecular transport
Jean-François Balligand is professor at the Université catholique de Louvain. His work at the Institute of Experimental and Clinical Research focuses on cardiac remodelling mechanisms, a collection of molecular and biological modifications of the cardiac muscle under stress (for example, a heart attack). This remodelling, which is characterised by cardiac hypertrophy, leads to heart failure. Jean-Luc Balligand and his team observed that cardiac cells express several water-channel isoforms on their plasma membrane – aquaporins – and discovered, unexpectedly, that mice deficient in Aquaporin-1 (Aqp-1) have a smaller heart and, when under cardiovascular stress, do not develop cardiac hypertrophy or fibrosis, phenomena that typically lead to heart failure.
The first two years of this WELBIO project shows that Aqp-1 not only allows for the transportation of water, but also hydrogen peroxide (H2O2), a molecule that is essential for mediating hypertrophic signals. A structural analysis of the Aqp-1 pore helped to identify the amino acids that are needed for the passage of H2O2 . These results have shown that Aquaporin-1 is, above all, a “peroxiporin”, that is, a channel for H2O2 .