# Cholesterol Regulation of Endothelial K+ Channels

> **NIH NIH R01** · UNIVERSITY OF ILLINOIS AT CHICAGO · 2022 · $653,821

## Abstract

Dyslipidemia-induced endothelial dysfunction plays a major role in the initiation of atherosclerosis. Our
studies discovered that plasma hypercholesterolemia results in suppression of endothelial inwardly-
rectifying K+ (Kir) channels and that Kir channels play a major role in endothelial response to flow. Our long
term goal is to elucidate the mechanisms responsible for cholesterol-induced regulation of endothelial ion
channels and determine the impact of cholesterol-induced suppression of Kir on vascular function and
atherosclerosis development. During the previous funding period of this grant, we discovered a new mode
of cholesterol-Kir2 interactions via multiple dynamic contacts, provided direct evidence that Kir2.1 plays a
crucial role in flow-induced vasodilation and NO release, and showed that hypercholesterolemia-induced
impairment of flow-induced vasodilation can be attributed to Kir2.1 suppression. In the current proposal, we
extend these studies to address three new goals: In Aim 1, we address the fundamental question of how
cholesterol binding to the specific binding sites that we have already identified translates into the inhibition
of channel gating. Specifically, we address a novel hypothesis based on our computational studies
predicting that cholesterol binding uncouples specific residues within the channels, crucial for the gating
process. This hypothesis will be addressed using a combination of multi-scale Molecular Dynamics
simulations, a state-of-the-art computational approach, followed by site-directed mutagenesis, functional
analysis of the channel function by high throughput electrophysiology, and biochemical and neutron
scattering studies to evaluate direct cholesterol interactions with Kir2 channels. In Aim 2, we will extend our
studies to determine the role of cholesterol suppression of Kir2.1 in two major endothelial flow responses: 1)
activation of PECAM1/Src/VEGFR2/PI3K/Akt signaling axis and 2) cytoskeleton remodeling. This aim is
based on our RNA sequencing analysis that revealed a major role of Kir2.1 in flow-sensitive gene
expression including the expression of PECAM1/VEGFR2 mechanosensor complex. Specifically, we will
test the hypothesis that suppression of endothelial Kir channels by hypercholesterolemic conditions impairs
flow-induced activation of VEGFR2 and activation of a small GTPase, RhoA, and alters flow-induced
cytoskeletal remodeling. Finally, in Aim 3, we will determine the role of endothelial Kir2.1 in lesion formation
of dyslipidemic mice. We have already established that the global deficiency of Kir2.1 exaggerates lesion
formation in dyslipidemic ApoE-/- mice. In the proposed study, we will determine if the effect is specific for
endothelial Kir2.1. Furthermore, we will also employ a new model of Kir2.1 rescue, a transgenic CRISPR
mouse that expresses a cholesterol-insensitive Kir2.1 mutant. We believe that taken together, these studies
will make a significant contribution to the understanding of c...

## Key facts

- **NIH application ID:** 10463812
- **Project number:** 5R01HL073965-15
- **Recipient organization:** UNIVERSITY OF ILLINOIS AT CHICAGO
- **Principal Investigator:** Irena Levitan
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $653,821
- **Award type:** 5
- **Project period:** 2004-04-01 → 2025-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10463812

## Citation

> US National Institutes of Health, RePORTER application 10463812, Cholesterol Regulation of Endothelial K+ Channels (5R01HL073965-15). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10463812. Licensed CC0.

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