SERCA2a gene transfer enhances eNOS expression and activity in endothelial cells

Area of Science:

• Cardiovascular Biology
• Gene Therapy
• Endothelial Function

Background:

• Congestive heart failure (HF) is characterized by impaired endothelium-dependent vasodilation.
• Nitric oxide (NO)-mediated pathways are crucial for maintaining vascular tone.
• Dysfunctional sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPase 2a (SERCA2a) impacts cellular calcium handling and endothelial function.

Purpose of the Study:

• To investigate the therapeutic potential of SERCA2a gene transfer in a swine model of heart failure.
• To assess the impact of SERCA2a gene transfer on endothelial function and coronary blood flow in HF.
• To elucidate the molecular mechanisms by which SERCA2a influences endothelial nitric oxide synthase (eNOS) activity.

Main Methods:

• Induction of heart failure via mitral regurgitation in swine.
• Intracoronary administration of adeno-associated virus (AAV) carrying SERCA2a or saline.
• Measurement of coronary flow (CF) and assessment of SERCA2a and eNOS protein expression.
• In vitro studies using human coronary artery endothelial cells (HCAECs) to evaluate eNOS activity and calcium signaling.

Main Results:

• SERCA2a gene transfer significantly restored reduced coronary flow in HF animals to sham levels.
• Restoration of SERCA2a and eNOS protein expression in coronary arteries of HF animals post-gene transfer.
• SERCA2a overexpression in HCAECs enhanced eNOS expression, phosphorylation, promoter activity, and downstream cyclic guanosine monophosphate (cGMP) production.
• Improved calcium homeostasis and enhanced histamine-induced calcium oscillations observed with SERCA2a overexpression.

Conclusions:

• SERCA2a gene transfer effectively improves endothelial function in a heart failure model.
• The mechanism involves enhanced eNOS expression and activity through modulation of intracellular calcium.
• SERCA2a gene therapy represents a promising strategy to improve vascular reactivity in heart failure patients.