Hypertension Induces Somatic Cellular Senescence in Rats and Humans by Induction of Cell Cycle Inhibitor p16 INK4a

Abstract

There is increasing evidence for a role of somatic cellular senescence in physiological aging but also in injury and disease. Cell cycle inhibitor p16 INK4a is the key mediator for stress and aberrant signaling induced senescence. Here we report that elevated blood pressure markedly induced p16 INK4a expression in rat kidneys and hearts, as well as in human kidneys. In kidneys from deoxycorticosterone acetate-salt–treated rats, p16 INK4a induction was found in tubular, glomerular, interstitial, and vascular cells and correlated with the typical histopathologic features of hypertensive target organ damage. p16 INK4a expression also correlated with phospho-p38, a positive upstream regulator of p16 INK4a expression. In left ventricles, increased p16 INK4a expression was found in myocardium and cardiac arteries. Antihypertensive medication consistent of hydrochlorothiazide, hydralazine, and reserpine ameliorated the histopathologic changes and attenuated p16 INK4a expression in kidneys of deoxycorticosterone acetate-salt–treated rats. Nonantihypertensive administration of spironolactone also reduced kidney damage and p16 INK4a expression. p16 INK4a induction was further observed in kidneys from hypertensive transgenic rats heterozygous for the mouse Ren-2 gene and was prevented by the angiotensin II type 1 receptor blocker losartan. In human kidney biopsies showing hypertensive nephrosclerosis, increased p16 INK4a expression was found compared with age-matched normotensive control subjects. Thus, hypertension induces cellular senescence via p16 INK4a , possibly through p38, thereby contributing to hypertensive target organ damage. This detrimental effect can be overcome by different therapeutic drug strategies.