Natriuretic peptides regulate the expression of tissue factor and PAI-1 in endothelial cells

Area of Science:

• Cardiovascular Physiology
• Endocrinology
• Hemostasis and Thrombosis

Background:

• Angiotensin II (Ang II) plays a critical role in regulating blood pressure and fluid balance.
• Ang II can induce pro-coagulant and anti-fibrinolytic factors, potentially contributing to thrombotic events.
• Natriuretic peptides, including BNP and CNP, are known for their vasodilatory and diuretic effects.

Purpose of the Study:

• To investigate the interaction between natriuretic peptides (BNP and CNP) and Ang II in the regulation of blood coagulation and fibrinolysis.
• To determine the effect of BNP and CNP on Ang II-induced expression of key hemostatic factors.

Main Methods:

• Analysis of tissue factor (TF) and plasminogen activator inhibitor-1 (PAI-1) mRNA expression using northern blotting.
• Measurement of TF activity on rat aortic endothelial cells (RAECs) via chromogenic assay.
• Quantification of PAI-1 activity in culture media using chromogenic assay.

Main Results:

• BNP and CNP significantly suppressed Ang II-induced TF and PAI-1 mRNA expression in a time- and concentration-dependent manner.
• The suppression of mRNA expression by BNP and CNP was mediated via the cyclic guanosine monophosphate (cGMP) cascade.
• These suppressions were associated with decreased TF and PAI-1 activities.
• Neither TFPI nor TPA mRNA expression was affected by BNP and CNP treatment.

Conclusions:

• BNP and CNP exert anticoagulant and profibrinolytic effects by inhibiting Ang II-mediated TF and PAI-1 induction.
• The cGMP pathway is involved in the inhibitory actions of BNP and CNP on TF and PAI-1 expression.
• These findings highlight a novel interaction between natriuretic peptides and the renin-angiotensin system in hemostasis regulation.