A loss-of-function polymorphism in the propeptide of lysyl oxidase exacerbates atherosclerosis
In-Hyuk Jung, Junedh M. Amrute, Sofia E. Luna, Ryan E. Wagoner, Arturo Alisio, Paul C. Lee, Kendall H. Burks, Joohee Oh, Hannah C. Plunkett Paletta, Chul Joo Kang, Nathan O. Stitziel
In-Hyuk Jung, Junedh M. Amrute, Sofia E. Luna, Ryan E. Wagoner, Arturo Alisio, Paul C. Lee, Kendall H. Burks, Joohee Oh, Hannah C. Plunkett Paletta, Chul Joo Kang, Nathan O. Stitziel
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Research Article Cardiology Vascular biology

A loss-of-function polymorphism in the propeptide of lysyl oxidase exacerbates atherosclerosis

Abstract

A single-nucleotide missense polymorphism (rs1800449, R158Q) in the propeptide domain of lysyl oxidase (LOX-PP) is associated with increased risk of coronary artery disease (CAD) independent of changes in plasma lipid levels. Although the enzymatic function of LOX has an essential role for the cross-linking of extracellular matrix proteins in connective tissues, whether and how LOX-PP R158Q contributes to the development of atherosclerosis has not been clearly established. Here, hypercholesterolemia was induced in mice that were WT or homozygous for the LOX-PP R158Q polymorphism by adeno-associated virus-8–mediated overexpression of Pcsk9 followed by high-fat diet feeding for 16 weeks. We found that the R158Q polymorphism promoted atherosclerosis and induced proliferation of macrophages and vascular smooth muscle cells without altering LOX enzymatic activity. Using single-cell RNA sequencing, we found the transcriptional program of atherosclerotic plaques from mice harboring R158Q was strongly enriched for proliferation- and calcification-related genes in a regionally distinct manner. Together, these results establish an enzymatically independent proatherogenic role for the LOX-PP and suggest its potential as a novel therapeutic target.

Authors

In-Hyuk Jung, Junedh M. Amrute, Sofia E. Luna, Ryan E. Wagoner, Arturo Alisio, Paul C. Lee, Kendall H. Burks, Joohee Oh, Hannah C. Plunkett Paletta, Chul Joo Kang, Nathan O. Stitziel

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Figure 2

Differential Lox expression patterns in mouse aortic vessels.

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Differential Lox expression patterns in mouse aortic vessels. (A–C) Diff...
(A–C) Differential expression patterns of Lox in aortic vessels, including the aortic root (A), BCA (B), and LC (C) from Apoe–/– mice after 16 weeks of HFD feeding using RNAscope ISH. Outlined dotted areas indicate the regions magnified in the next panels. (D–F) Comparison of Lox expression patterns between LoxWT and LoxR152Q mice after 16 weeks of HFD feeding using RNAscope ISH. Aortic roots (D and E) and BCAs (F) were used and costained for the VSMC marker SMα-actin. Outlined areas indicate the regions magnified in the next 2 panels. Gray arrows (shown in regions 1 and 2 in D and E) indicate basal expression of Lox by VSMCs in the medial layer of aortic roots compared with its expression in fibrous cap from both genotypes. Yellow arrows (shown in F) indicate higher expression of Lox by VSMCs in the medial layer of BCAs along with its expression in fibrous cap from both genotypes. (G) Quantification of relative Lox intensity in aortic vessels normalized to SMα-actin intensity. Scale bars: 200 μm (A–C) and 100 μm (D–F). Data were analyzed with 2-way ANOVA test, and are shown as the mean ± SEM.