Objective   Chiral medicines selectively interact with biological macromolecules through strict chiral recognition and demonstrate different pharmacokinetic characteristics and drug effects. To investigate the differential protein expressions in vascular smooth muscle cells (VSMCs) treated with 2 atenolol enantiomers

(R)-ATN and (S)-ATN.   Methods   Cell proliferation was detected with MTT assay when VSMCs were treated with (R)-ATN or (S)-ATN at 0

0.15

1.5

15

30

60

120

180 and 240 μmol/L respectively for 4 h. After the VSMCs were treated with 120 μmol/L (R)-ATN or (S)-ATN for 4 h

the cell proteins were extracted. Then

differential protein expression was assessed. The differential expression protein spots from (R)/(S)-ATN treated VSMCs were screened by 2-DE

and then analyzed by on-line two-dimensional nano liquid chromatography (HPLC-CHIP included an enrichment column of Zorbax 300SB-C18 and an analytical column of Zorbax 300SB C18) coupled with linear ion trap mass spectrometry.   Results   There were 6 differential proteins founded between VSMCs treated by (R)/(S)-ATN

including enhancer of filamentation 1

AP-3 complex subunit beta-1

malate dehydrogenase

mitochondrial precursor

glyceraldehyde-3-phosphate dehydrogenase

and uncharacterized protein C3orf19 were screened. The former 5 proteins were related to cardiovascular events.   Conclusion   Our results indicates that there are differential protein expressions in VSMCs treated with 2 atenolol enantiomers

(R)-ATN and (S)-ATN

so more attention should be paid chiral drugs.