# IL1β Promotes Atheroprotective Changes in Late Stage Atherosclerotic Lesions

> **NIH NIH F30** · UNIVERSITY OF VIRGINIA · 2020 · $31,003

## Abstract

PROJECT SUMMARY: Complications resulting from rupture of unstable atherosclerotic lesions, including myocardial
infarction and stroke, are the leading cause of death worldwide. Despite decades of research, the mechanisms and
factors leading to plaque rupture remain poorly understood. It is generally accepted that lesions with a high smooth
muscle cell (SMC) to macrophage (Mϕ) ratio are less likely to rupture. However in the setting of atherosclerosis, SMC
down-regulate their characteristic markers and express markers of other cells types and thus are undetectable using
traditional markers. Indeed, rigorous SMC lineage tracing studies by our lab using Myh11 ERT2Cre eYFP ApoE-/- mice
have shown that >80% of SMC within lesions lack expression of the markers previously used for their identification
and that nearly 30% of these cells have activated multiple markers of Mϕ. Therefore, the number of SMC within
lesions has not only been grossly underestimated, but many cells thought to be Mϕ are actually SMC-derived. Of even
greater significance, we showed that SMC-specific conditional knockout of the stem cell pluripotency genes Klf4 and
Oct4 had a profound impact on the pathogenesis of lesions including alterations in multiple indices of plaque stability.
However, contrary to the dogma that SMC are always atheroprotective, we showed they can be either
atheroprotective or -promoting depending on the nature of their phenotypic transitions. Taken together, studies
highlight the importance of identifying factors and mechanisms that promote beneficial changes in SMC phenotype.
 An ongoing clinical trial is investigating neutralization of interleukin-1 in high-risk cardiovascular patients. The
overarching hypothesis is that inflammation drives atherosclerosis, and that inhibition of inflammation will improve
patient survival. However, there is a lack of preclinical evidence that neutralization of IL1 will confer beneficial effects
in the setting of advanced atherosclerosis. Indeed, recent studies from our lab, which included the applicant, showed
that treatment of our Myh11 ERT2Cre eYFP ApoE-/- mice with the Novartis IL1-neutralizing antibody after the
establishment of advanced atherosclerosis resulted in multiple changes consistent with reduced plaque stability
including marked reductions in the number of SMC-derived eYFP+ cells within the fibrous cap, and replacement of
these cells with Mϕ. Studies in this proposal will test the hypothesis that IL1 signaling in SMC is critical for
maintenance of plaque stability in late-stage atherosclerosis. Aim 1 test the hypothesis that the detrimental effects of
anti-IL1 Ab treatment on late-stage atherosclerosis are primarily mediated through IL1R1 signaling in SMC and that
this results in deleterious phenotypic transitions in lesion SMC. Aim 2 will test the hypothesis that increased production
of interleukin-4 (IL4) following anti-IL1 Ab treatment of Myh11 ERT2Cre eYFP ApoE-/- mice with advanced lesions
contribu...

## Key facts

- **NIH application ID:** 10005432
- **Project number:** 5F30HL136188-04
- **Recipient organization:** UNIVERSITY OF VIRGINIA
- **Principal Investigator:** Richard Baylis
- **Activity code:** F30 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $31,003
- **Award type:** 5
- **Project period:** 2017-09-30 → 2021-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10005432

## Citation

> US National Institutes of Health, RePORTER application 10005432, IL1β Promotes Atheroprotective Changes in Late Stage Atherosclerotic Lesions (5F30HL136188-04). Retrieved via AI Analytics 2026-06-01 from https://api.ai-analytics.org/grant/nih/10005432. Licensed CC0.

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