# Molecular biophysics of integrin activation by oxysterols and rational discovery of small-molecule modulators

> **NIH NIH R01** · WASHINGTON STATE UNIVERSITY · 2020 · $290,700

## Abstract

PROJECT SUMMARY/ABSTRACT
Oxysterols are oxygenated metabolites of cholesterol formed in the human body and are involved in a plethora
of physiological and pathological processes such as lipid homeostasis, inflammation, innate and adaptive
immunity, cancer, and brain degenerative diseases. Specifically, 25-hydroxycholesterol (25HC) is now
established as an important regulator of the immune system, and is produced by immune cells in response to
viral infection and activation of pattern recognition receptors. Recently, we uncovered a novel cellular mechanism
of 25HC-mediated regulation of the proinflammatory response. We showed that 25HC amplifies the activation of
immune cells and increases the production of immune mediators such as TNF and IL-6, by directly binding to
αvβ3 and α5β1 integrins and activating the integrin-focal adhesion kinase pathway. We also discovered that
25HC binds to integrins at a novel binding site (site 2), distinct from the site where the extracellular matrix (ECM)
ligands containing an Arg-Gly-ASP (RGD) motif are known to bind. Binding of 25HC at site 2 produces significant
conformational changes in the specificity-determining loop (SDL) of integrins, near the RGD-binding site. The
effect of such conformational changes in the SDL on the binding of ECM ligands, as well as the basis of 25HC-
mediated allosteric signaling mechanism underlying integrin activation, are not known. Our hypothesis is that
binding of 25HC to integrins at site 2 triggers conformational changes in the SDL that result in efficient binding
of ECM ligands producing further modification of innate inflammatory response. We also hypothesize that small
molecule modulators blocking 25HC-integrin interaction would serve as an efficient anti-inflammatory therapeutic
strategy to combat various inflammatory diseases. Accordingly, the central objective of this proposal is to
elucidate the molecular mechanisms of integrin activation by oxysterols and to identify selective small molecule
modulators targeting site 2 of integrins for potential therapeutic applications. The objective of this project will be
accomplished by the following three specific aims: 1) elucidate the molecular basis and conformational dynamics
of integrin activation by 25HC; 2) examine the molecular recognition of integrins by non-25HC oxysterols; and
3) identify and evaluate small-molecule modulators targeting the 25HC binding site of integrins. We will utilize
state-of-the-art computational techniques such as molecular docking, molecular dynamics simulations, and
pharmacophore-based virtual screening to delineate the structural basis and conformational dynamics involved
in activation of integrins and to identify high affinity ligands for site 2 of integrins. In addition, our well-established
in vitro and in vivo models will be employed to validate our in silico findings and evaluate top ligands. Our
multidisciplinary approach is innovative and together, the proposed studies will have a broad ...

## Key facts

- **NIH application ID:** 9946339
- **Project number:** 1R01GM137022-01
- **Recipient organization:** WASHINGTON STATE UNIVERSITY
- **Principal Investigator:** Senthil Kumar Natesan
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $290,700
- **Award type:** 1
- **Project period:** 2020-09-10 → 2024-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9946339

## Citation

> US National Institutes of Health, RePORTER application 9946339, Molecular biophysics of integrin activation by oxysterols and rational discovery of small-molecule modulators (1R01GM137022-01). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9946339. Licensed CC0.

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