ADAMTS7 promotes smooth muscle foam cell expansion in atherosclerosis
Allen Chung, Lauren E. Fries, Hyun-Kyung Chang, Huize Pan, Alexander C. Bashore, Karissa Shuck, Caio V. Matias, Juliana Gomez Pardo, Jordan S. Kesner, Hanying Yan, Mingyao Li, Robert C. Bauer
Allen Chung, Lauren E. Fries, Hyun-Kyung Chang, Huize Pan, Alexander C. Bashore, Karissa Shuck, Caio V. Matias, Juliana Gomez Pardo, Jordan S. Kesner, Hanying Yan, Mingyao Li, Robert C. Bauer
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Research Article Cardiology Vascular biology

ADAMTS7 promotes smooth muscle foam cell expansion in atherosclerosis

Abstract

Human genetic studies have repeatedly associated ADAMTS7 with atherosclerotic cardiovascular disease. Subsequent investigations in mice demonstrated that ADAMTS7 is proatherogenic and induced in response to vascular injury. However, the cell-specific mechanisms governing ADAMTS7 proatherogenicity remain unclear. To determine which vascular cell types express ADAMTS7, we interrogated single-cell RNA-seq of human carotid atherosclerosis and found ADAMTS7 expression in smooth muscle cells (SMCs), endothelial cells (ECs), and fibroblasts. We subsequently created SMC- and EC-specific Adamts7 conditional KO and transgenic mice. Conditional KO of Adamts7 in either cell type did not reduce atherosclerosis, whereas transgenic induction in either cell type increased atherosclerosis. In SMC transgenic mice, this increase coincides with an expansion of lipid-laden SMC foam cells and a decrease in fibrous cap formation. RNA-seq of Adamts7-overexpressing SMCs revealed an upregulation of lipid genes typically assigned to macrophages. Mechanistically, ADAMTS7 increases SMC oxidized LDL uptake through CD36, whose expression is upregulated by PU.1. Assay for transposase-accessible chromatin using sequencing (ATAC-seq) and motif analysis revealed increased chromatin accessibility at AP-1–enriched regions, consistent with AP-1–dependent remodeling of PU.1-regulated lipid-handling loci. In summary, ADAMTS7 promotes atherosclerosis by driving SMC foam cell formation through an AP-1/PU.1/CD36 regulatory axis.

Authors

Allen Chung, Lauren E. Fries, Hyun-Kyung Chang, Huize Pan, Alexander C. Bashore, Karissa Shuck, Caio V. Matias, Juliana Gomez Pardo, Jordan S. Kesner, Hanying Yan, Mingyao Li, Robert C. Bauer

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Figure 4

ADAMTS7 promotes foam cell expansion.

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ADAMTS7 promotes foam cell expansion. (A) Flow cytometry–based quantific...
(A) Flow cytometry–based quantification of foam cells through LipidTOX staining of the aorta. A normolipidemic aorta was used to establish the LipidTOX high gate. n = 3. (B) Breakdown of foam cells stained positively for CD11B and CD64. n = 3. (C) Confirmation of efficient ZsGreen labeling of SMCs with nuclei counterstained with DAPI. Scale bar: 500 μm. (D) Foam cell analysis with the SMC lineage tracer ZsGreen and leukocyte marker CD45 after 12 weeks of WTD. Counts were normalized to 100,000 live cells. n = 4–6 mice. Statistics were analyzed by 2-way ANOVA with Šidák’s multiple comparison test. (E) Flow cytometry–based quantification of foam cells through LipidTOX staining of the aorta. A normolipidemic aorta was used to establish the LipidTOX high gate. n = 3–4. (F) Normalized foam cell counts out of 100,000 live cells after 16 weeks of WTD. Leukocytes were identified as CD45+. SMCs were identified as CD31– CD45– CD200+. n = 10–11 mice. Statistics were analyzed by 2-way ANOVA with Šidák’s multiple comparison test. (G) In vitro foam cell analysis with primary cells from transgenic mice treated with 10 μg/mL DiI-oxLDL for 24 hours. n = 4. (H) In vitro foam cell analysis with explanted primary SMCs from whole-body Adamts7 KO mice treated with 10 μg/mL DiI-oxLDL for 24 hours. n = 3. ****P < 0.0001, ***P < 0.001, ** P < 0.01, *P < 0.05 Between-sample comparisons were analyzed by a 2-tailed Student’s t test.