Submitted on December 8, 2004
Accepted on June 9, 2005
Regulation of angiotensin converting enzyme production by nicotine in human endothelial cells
Outi Saijonmaa1*, Tuulikki Nyman2, and Frej Fyhrquist1
1 Minerva Institute for Medical Research, Helsinki, Finland; Department of Internal Medicine, Helsinki University Central Hospital, Helsinki, Finland
2 Minerva Institute for Medical Research, Helsinki, Finland
* To whom correspondence should be addressed. E-mail: outi.saijonmaa{at}helsinki.fi.
Objective: Nicotine, a component of cigarette smoke, has been implicated in the pathogenesis of cardiovascular diseases. We examined whether nicotine regulates angiotensin-converting enzyme (ACE), an enzyme which plays an important role in the pathophysiology of atherosclerosis and hypertension.
Methods: Human umbilical cord vein endothelial cells (HUVECs) were treated with nicotine (0.1-1µM) alone or in combination with vascular endothelial growth factor (VEGF, 0.5 nM) or GF109203X (GFX, 2.5 µM).
ACE amount in intact endothelial cells was measured by an inhibitor binding assay (IBA) method, and ACE mRNA levels by LightCycler technology. Phosphorylated PKC levels was measured by Western immunoblotting.
Results: Nicotine did not modulate basal ACE production but significantly potentiated VEGF induced ACE upregulation. Treatment of endothelial cells with a PKC inhibitor, GFX (2.5 µM) totally blocked VEGF and nicotine induced ACE upregulation. VEGF induced PKC phosphorylation, which was potentiated by co-treatment with nicotine.
Conclusions: Nicotine significantly potentiated VEGF induced ACE upregulation. This effect was probably mediated by PKC phosphorylation. Interaction of nicotine with VEGF in ACE induction may contribute to the pathogenesis of smoking-related cardiovascular diseases.
