LIM Kinase Inhibition Diminishes Hypertension and Vasoconstriction‐Induced Inward Remodeling in Mouse and Human Resistance Arteries

Abstract

Vascular remodeling is an early biomarker of cardiovascular disease (CVD) related to structural changes in resistance arteries (RA). Arteriolar inward remodeling, characterized by a reduced luminal diameter that is associated with changes in the homeostasis of actin polymerization/depolymerization pathways, is posited to precede the development of hypertension. We hypothesize that inward remodeling involves changes in the actin cytoskeleton that facilitate cell motility and the rearrangement of vascular smooth muscle cells (VSMCs) around the vascular lumen. Moreover, we predict that inhibition of actin polymerization with a Lim kinase (LIMK) inhibitor would block the inward remodeling process associated with prolonged vasoconstriction and hypertension. We have previously reported in ex vivo experiments in rats that long‐term exposure of RA to vasoconstrictors induces vascular inward remodeling via activation of the Rho pathway, which in part promotes actin polymerization. We now demonstrate that VSMCs increase the inward remodeling ratio of filamentous to globular actin (F/G‐actin) in response to GPCR‐activation by a norepinephrine (NE) and angiotensin‐II (AngII). GPCR‐mediated Rho activates (LIMK), which subsequently phosphorylates and inactivates the actin severing enzyme, cofilin, thus effecting an increase in F/G‐actin ratios. In isolated rat cremasteric RA we have demonstrated that LIMK inhibition blocks the inward remodeling induced by of GPCR agonists and that this is coincident with a reduction in cofilin phosphorylation. To study the arterial remodeling process in vivo, we imaged the outer ear of a transgenic mouse line that expresses smooth muscle actin‐GFP in VSMCs by multiphoton microscopy. We treated these mice with AngII (1000ng/kg/min) for 14 days to induce vasoconstriction and hypertension. We imaged the same resistance artery within each ear before (Day 0) and after (Day 14) AngII infusion to study the progression of remodeling over time. Starting at day 0, one ear was injected every four days with a LIMK inhibitor (LIMKi), while the other ear received vehicle (control). We observed a significant inward remodeling in vessels of the control ear compared to those of the ear treated with LIMKi (p<0.05). We then assessed the effect of LIMKi in the inward remodeling process associated with ex vivo prolonged vasoconstriction in isolated human RA from omental tissues and studied by pressure myography under passive conditions before and after a 4h incubation in the presence of NE + AngII (control) or NE + AngII + LIMKi. Exposure to NE + AngII induced vascular inward remodeling that was completely ablated by presence of LIMKi and resulted in outward remodeling (p<0.05). These data indicate that LIMK plays a necessary role in the vasoconstriction‐hypertension vascular remodeling process that makes it a potential target for the treatment of CVDs associated with resistance artery inward remodeling.Support or Funding InformationNational Institutes of Health grants: R01 HL137769 (JP), R01 HL088105 (LM‐L).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.