The Effect of Endothelin-1 on Gene Expression of Nicotinamide Adenine Dinucleotide Phosphate (NADPH) Oxidase via Transforming Growth Factor Beta (TGF- β) Receptor in Human Aortic Smooth Muscle Cells

Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (Nox) is one of the predominant sources of the production of free oxygen radicals in the vascular wall. Endothelin-1 is a potent vasoconstrictor factor that also has mitogenic activity in vascular smooth muscle cells. The activation of transforming growth factor beta (TGF–β) receptor by endothelin-1 plays an important role in cardiovascular diseases. The aim of this study was to investigate the changes of Nox gene expression in smooth muscle cells treated with endothelin-1 in the presence of the transforming growth factor beta-receptor antagonist.
Human aortic smooth muscle cells (HA-SMCs) were treated with endothelin-1 (100 nM) and transforming growth factor beta (2 ng/ml) in the presence and absence of transforming growth factor beta-receptor antagonist. The mRNA expression of Nox1 and Nox4 were assessed using real-time polymerase chain reaction (PCR) technique.
Findings: The gene expression of Nox1 increased in the presence of endothelin-1 compared to control group, but there was no change in gene expression of Nox4. Increasing the expression of Nox1 decreased in the presence of transforming growth factor beta-receptor antagonist (10 μM).
The results of this study showed that activation of transforming growth factor beta pathway is one of the mechanisms for increasing the mRNA expression of Nox1 by endothelin-1.