# Project 3 - HDL Structure/Function in LCAT Deficient Humans

> **NIH NIH P01** · VANDERBILT UNIVERSITY MEDICAL CENTER · 2020 · $262,515

## Abstract

We propose to investigate the structural basis of the interaction of LCAT with HDL. We will complement these
in vitro studies with analyses of HDLs of subjects with LCAT deficiency. Because these patients have very low
HDL-C levels but apparently little increased cardiovascular risk, their HDL might provide important insights
about HDL functions that are cardioprotective but do not involve HDL-C. We have three specific aims.
First, based on the crystal structures of apoA-I and apoA-IV, we will introduce specific point mutations into
apoA-I to determine their impact on its binding sites and activation of cholesteryl ester synthesis by LCAT. In
parallel studies, we will use chemical cross-linking together with high-resolution mass spectrometry to identify
the precise sites of interaction of LCAT with apoA-I in reconstituted HDLs. Using these data, we will test
structural models of HDL established with reconstituted and native HDLs by Segrest and Davidson.
Second, we use a method we recently developed, termed calibrated ion mobility analysis, to quantify the
concentration and size of HDL species in the blood of control and LCAT deficient subjects. We hypothesize
that normal or higher levels of certain HDL subspecies are sufficient for cardioprotection in LCAT-deficient
humans, even in the absence of other forms of HDL.
Third, using macrophages, we will assess the sterol efflux capacity of HDLs from LCAT-deficient and control
subjects. Efflux by ABCA1 and ABCG1 will also be quantified, using genetically engineered cell lines. We will
use both serum HDL (serum depleted of apoB-containing lipoproteins), isolated HDL, and reconstituted
discoidal and spherical HDL particles for our studies We hypothesize that the very small HDL subspecies
present at normal levels in LCAT deficient subjects is a potent mediator of sterol efflux and HDL-mediated
cardioprotection.

## Key facts

- **NIH application ID:** 9951102
- **Project number:** 5P01HL128203-05
- **Recipient organization:** VANDERBILT UNIVERSITY MEDICAL CENTER
- **Principal Investigator:** JAY W HEINECKE
- **Activity code:** P01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $262,515
- **Award type:** 5
- **Project period:** — → 2022-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9951102

## Citation

> US National Institutes of Health, RePORTER application 9951102, Project 3 - HDL Structure/Function in LCAT Deficient Humans (5P01HL128203-05). Retrieved via AI Analytics 2026-05-28 from https://api.ai-analytics.org/grant/nih/9951102. Licensed CC0.

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