A novel interaction between soluble epoxide hydrolase and the AT1 receptor in retinal microvascular damage

Area of Science:

• Ophthalmology
• Vascular Biology
• Endocrinology

Background:

• The renin-angiotensin system (RAS) is a potential therapeutic target for diabetic retinopathy (DR).
• AT1 receptor blockade reduced DR incidence but not progression, indicating a need for better understanding of RAS-induced retinal microvascular damage.
• Molecular mechanisms linking RAS to retinal microvascular damage remain unclear, hindering effective therapeutic strategies.

Purpose of the Study:

• To investigate the interaction between soluble epoxide hydrolase (sEH) and the AT1 receptor in Angiotensin II (Ang II)- and diabetes-induced retinal microvascular damage.
• To elucidate the role of sEH in the pathogenesis of DR.
• To explore novel therapeutic strategies for DR involving sEH and AT1 receptor pathways.

Main Methods:

• Assessed retinal sEH levels in response to Ang II and AT1 receptor blockade.
• Administered 11,12-epoxyeicosatrienoic acid (EET) to evaluate its effect on Ang II-induced retinal albumin leakage.
• Utilized sEH knockout (KO) mice to study Ang II- and diabetes-induced retinal damage, including vascular remodeling, leakage, and expression of VEGF and tight junction proteins (ZO-1, occludin).

Main Results:

• Ang II increased retinal sEH levels, an effect blunted by AT1 receptor blockade.
• EET administration exacerbated Ang II-induced retinal albumin leakage.
• sEH KO and blockade reduced Ang II-induced retinal vascular remodeling, but sEH KO led to vascular leakage in Ang II-treated mice.
• sEH KO potentiated diabetes-induced retinal damage by increasing VEGF and decreasing ZO-1 and occludin expression.

Conclusions:

• sEH plays a significant role in Ang II- and diabetes-induced retinal microvascular damage.
• Combined blockade of EETs and AT1 receptor presents a promising therapeutic strategy for preventing or reducing DR.
• Targeting the sEH-AT1 receptor interaction could offer a novel approach to managing diabetic retinopathy.