Proteomic and phosphoproteomic identified structural and functional changes in the aorta associate with age-dependent hypertension in male Sprague-Dawley rats

Hypertension affects 1 in 2 U.S. adults and hypertension prevalence increases with aging. Both hypertension and aging can cause arterial remodeling. We investigated the hypothesis that aortic remodeling contributes to age-dependent hypertension in male Sprague Dawley (SD) rats. Compared to young 3-month-old rats 16-month-old male SD rats developed age-dependent hypertension that associated with increased sympathetic tone to the vasculature, elastin disarray and blood pressure variability. Our quantitative proteomic/phosphoproteomic workflow of the aorta identified 2366 proteins and 226 phosphoproteins, from which 58 proteins and 39 phosphoproteins were differentially expressed or phosphorylated respectively between young normotensive controls and aged hypertensive animals. Analysis of the proteome highlighted significant changes in the extracellular matrix, actin cytoskeleton and inflammatory pathways. Analysis of the differential phosphoproteome revealed significant differences in synapse and neuron projection and vascular smooth muscle cell (VSMC) function including actin remodeling and focal adhesions. STRING hypertension network analysis identified 13 differentially expressed and 10 differentially phosphorylated proteins associated with hypertension. Within the STRING analysis we observed 2 major areas of correlation of alterations in the aorta proteome with increased hypertension risk score - vascular inflammation and VSMC function. The majority of the identified phosphorylation sites (78.57%) in hypertension-relevant hyperphosphorylated proteins were located at serine residues. Collectively, we report that arterial remodeling in age-dependent hypertension is associated with an altered extracellular matrix and actin cytoskeleton and modulation of VSMC focal adhesion networks and neuron/synapse interactions.