# Macrophage-derived microcalcificaitons

> **NIH NIH R01** · BRIGHAM AND WOMEN'S HOSPITAL · 2020 · $661,115

## Abstract

Project Summary
This research project will test the hypothesis that, in the diabetic milieu, S100A9 induces the calcification
potential of macrophage-derived extracellular vesicles (EV), precursors of microcalcifications, contributing to
the biomechanical instability of the vulnerable atherosclerotic plaque. S100A9, a recently identified
biomarker of vulnerable plaques, increases in the blood of patients with type 1 diabetes, is expressed by
macrophages, and is a component of EV. Our published studies linked macrophages and calcification, and
showed that macrophages can release EV with a high calcification potential. The present study will explore
further the role of proinflammatory macrophages in vascular calcification in diabetes. Specific Aim 1 will
test the hypothesis in vitro that diabetic milieu promotes macrophage activation and accelerates release and
mineralization of S100A9–enriched EV. These experiments will involve innovative methods for detection of
EV microcalcifications and macrophage phenotypes, including density dependent scanning electron
microscopy (DDSEM) combined with elemental analysis, high-resolution microscopy, nanoparticle tracking
analysis, 3D-hydrogel system, proteomics, single cell RNA sequencing, and network analyses. Specific
Aim 2 will test the hypothesis in vivo that S100A9 mediates diabetes-induced microcalcifications in
atherosclerotic plaques. We expect that i) genetic deletion of S100A9, ii) macrophage-targeted siRNA
silencing of S100A9, and iii) bone marrow transplantation from S100A9-deficient mice will retard the
progression of microcalcification and subsequent rupture, as determined by molecular imaging and
comprehensive histopathological analyses. Specific Aim 3 will quantitatively evaluate the impact of
microcalcification on the biomechanical instability of the atherosclerotic plaque, using mathematical
modeling and finite element analysis. These complementary studies will advance the field by identifying the
role of macrophage S100A9 in microcalcification. To facilitate clinical translation of mouse data, we will
employ human primary macrophages and atherosclerotic plaque specimens from patients with diabetes.
The findings from this project will help to develop much needed anti-calcification therapies.

## Key facts

- **NIH application ID:** 9882311
- **Project number:** 5R01HL136431-04
- **Recipient organization:** BRIGHAM AND WOMEN'S HOSPITAL
- **Principal Investigator:** Elena Aikawa
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $661,115
- **Award type:** 5
- **Project period:** 2017-03-24 → 2022-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9882311

## Citation

> US National Institutes of Health, RePORTER application 9882311, Macrophage-derived microcalcificaitons (5R01HL136431-04). Retrieved via AI Analytics 2026-06-02 from https://api.ai-analytics.org/grant/nih/9882311. Licensed CC0.

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