Adenovirus-mediated transfer of the atrial natriuretic peptide gene in ratpulmonary vascular smooth muscle cells leads to apoptosis

Atrial natriuretic peptide (ANP) exhibits relaxant and growth-inhibiting ef fects on vascular smooth muscle cells (VSMCs), To obtain ANP gene expressio n in VSMCs, we built a recombinant adenovirus containing the ANP cDNA contr olled by the adenovirus major late promotor (AdMLP-ANP), After pulmonary VS MC treatment with AdMLP-ANP at a multiplicity of infection ranging from 5 t o 100 TCID50/cell, immunoreactive ANP was detectable in the cell culture me dium at a level that reached 101 +/- 27 pmol/well after 2 days. The newly e xpressed ANP was biologically active, as evidenced by its ability to induce cyclic guanosine monophosphate accumulation in target cells and to mimic t he effect of exogenous ANP (10(-8) to 10(-7) mol/L). Cell growth and surviv al of AdMLP-ANP-infected cells were decreased and were associated with the promotion of VSMC apoptosis, These effects, which occurred at a multiplicit y of infection of 10 to 100 TCIDB50/cell, were observed neither in cells in fected with the control adenoviral constructs (AdMLP-beta GAL and AdMLP-gD) nor in cells treated with exogenous ANP (10(-7) to 10(-6) mol/L), These re sults showing VSMC apoptosis in response to ANP gene expression may have im portant implications for the prevention of vascular remodeling by gene ther apy.