Investigation of chiralities of propranolol and atenolol by comparative proteomic analysis of vascular smooth muscle cells

Abstract

Propranolol is a nonselective /^-blocker exerting blocking effect on the /^-adrenergic receptors, with the S-enantiomer being more active than the /?-enantiomer. Utilization of iTPvAQ coupled with two-dimensional LC-MS/MS system, we report here the first study of protein profiles in vascular smooth muscle cells (A7r5) in response to two individual enantiomers of propranolol, respectively. In this study four categories of cellular proteins including cytoskeletal proteins, signaling molecules, metabolic enzymes and those associated with DNA synthesis/protein translation showed differentially expressed protein levels. The higher protein levels of several enzymes involved in cellular anabolism and antioxidant activity in S-enantiomer of propranolol-incubated A7r5 cells, as revealed by LC MS/ MS, was further validated by real-time PCR. Significantly, the increase in the anabolic activity associated with the higher level of metabolic enzymes was also supported by the higher intracellular concentration of the metabolic cofactor NAD + , which was the product resulting from oxidation of NADH. The higher expression level of thioredoxin might account for increased antioxidant activity, as indicated by the lower ROS level in S-enantiomer of propranolol-incubated cells than that for /?-enantiomer of propranolol-incubated cells and control ones. Atenolol is a /?i-selective drug, exhibiting greater blocking activity on /?i-adrenoreceptors than on /?2 ones, with the S-enantiomer being more active than /?-enantiomer. It was found that a number of metabolic enzymes ouch as glutathione S-transferase P, aspartate aminotransferase, NADH-cytochrome 65 reductase, and alpha-N-acetylgalactosaminidase precursor were up-regulated in the A7r5 cells