Endophilin A2 improves endothelial dysfunction by counteracting eNOS proteasomal degradation

Area of Science:

• Cardiovascular Biology
• Molecular Mechanisms of Disease
• Hypertension Pathophysiology

Background:

• Hypertension is a major cardiovascular risk factor linked to endothelial dysfunction and altered endothelial nitric oxide synthase (eNOS) activity.
• Endophilin A2 (EndoA2), enriched in the cardiovascular system, is a potential regulator of endothelial function and eNOS activity.
• Mechanisms controlling eNOS turnover and its impact on blood pressure homeostasis are not fully understood.

Purpose of the Study:

• To investigate the role of Endophilin A2 (EndoA2) in blood pressure regulation.
• To elucidate the molecular mechanisms by which EndoA2 influences endothelial nitric oxide synthase (eNOS) protein stability.
• To assess the therapeutic potential of targeting the EndoA2-eNOS interaction.

Main Methods:

• Generation of global and endothelial cell-specific EndoA2 knockout mice.
• Assessment of blood pressure using radiotelemetry.
• Histological, cellular, molecular, and biochemical analyses to investigate vascular function and eNOS regulation.
• In vivo studies using proline-rich domain (PRD)-mimetic peptides.

Main Results:

• Reduced EndoA2 expression correlates with hypertension in animal models.
• EndoA2 deficiency in mice leads to spontaneous hypertension, vascular remodeling, and impaired vasodilation.
• EndoA2 stabilizes eNOS by competing with the E3 ligase Itch, preventing eNOS ubiquitination and degradation.
• A PRD-mimetic peptide mimicking EndoA2's action reduced eNOS degradation and hypertension in mice.

Conclusions:

• Endophilin A2 (EndoA2) is crucial for maintaining eNOS stability by inhibiting Itch-mediated ubiquitination.
• Targeting the EndoA2-Itch-eNOS axis offers a potential therapeutic strategy for endothelial dysfunction and hypertension.
• PRD-mimetic peptides show promise in preserving eNOS homeostasis and treating hypertension.