Smooth muscle LRRC8A knockout preserves vascular function in AngII hypertension

Area of Science:

• Cardiovascular Biology
• Molecular Medicine
• Renal Physiology

Background:

• Angiotensin II (AngII) induces hypertension and vascular inflammation via cytokines.
• NADPH oxidase 1 (Nox1) and Leucine Rich Repeat Containing 8A (LRRC8A) anion channels are activated by AngII and TNFα in vascular smooth muscle cells (VSMCs).
• LRRC8A channels modulate inflammation and contractility, and VSMC-specific LRRC8A knockout (KO) protects against TNFα-induced vascular injury.

Purpose of the Study:

• To investigate the role of LRRC8A in AngII-induced hypertension and vascular dysfunction.
• To determine if LRRC8A KO preserves vascular function and reduces blood pressure (BP) in AngII-infused mice.

Main Methods:

• AngII infusion in wild type (WT) and LRRC8A KO mice for 14 days.
• Measurement of systolic blood pressure and BP dipping patterns.
• Assessment of vascular contractility and relaxation in response to various stimuli.
• Western blotting for key signaling proteins and analysis of vascular proliferation, antioxidant enzymes, and senescence markers.

Main Results:

• Systolic BP was similar between groups, but KO mice exhibited preserved BP dipping after AngII infusion.
• LRRC8A KO vessels showed less impairment in contractility and preserved relaxation after AngII exposure.
• KO aortae displayed increased soluble guanylate cyclase alpha, reduced CPI-17, lower Rho kinase activity, and reduced phosphorylation of ERM and Cofilin.
• AngII induced less proliferation, antioxidant enzyme induction, and senescence marker expression in KO vessels.

Conclusions:

• LRRC8A channels are not required for AngII-induced contraction but support the associated inflammatory response.
• LRRC8A KO preserves vascular function and modifies blood pressure dipping patterns in response to AngII.
• Targeting LRRC8A may offer a therapeutic strategy for hypertension-related vascular complications.