Smooth muscle cell–specific fibronectin-EDA mediates phenotypic switching and neointimal hyperplasia
Manish Jain, … , Steven R. Lentz, Anil K. Chauhan
Manish Jain, … , Steven R. Lentz, Anil K. Chauhan
Published November 25, 2019
Citation Information: J Clin Invest. 2020;130(1):295-314. https://doi.org/10.1172/JCI124708.
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Research Article Vascular biology

Smooth muscle cell–specific fibronectin-EDA mediates phenotypic switching and neointimal hyperplasia

Abstract

Fibronectin–splice variant containing extra domain A (Fn-EDA) is associated with smooth muscle cells (SMCs) following vascular injury. The role of SMC-derived Fn-EDA in SMC phenotypic switching or its implication in neointimal hyperplasia remains unclear. Herein, using human coronary artery sections with a bare metal stent, we demonstrate the expression of Fn-EDA in the vicinity of SMC-rich neointima and peri-strut areas. In mice, Fn-EDA colocalizes with SMCs in the neointima of injured carotid arteries and promotes neointima formation in the comorbid condition of hyperlipidemia by potentiating SMC proliferation and migration. No sex-based differences were observed. Mechanistic studies suggested that Fn-EDA mediates integrin- and TLR4-dependent proliferation and migration through activation of FAK/Src and Akt1/mTOR signaling, respectively. Specific deletion of Fn-EDA in SMCs, but not in endothelial cells, reduced intimal hyperplasia and suppressed the SMC synthetic phenotype concomitant with decreased Akt1/mTOR signaling. Targeting Fn-EDA in human aortic SMCs suppressed the synthetic phenotype and downregulated Akt1/mTOR signaling. These results reveal that SMC-derived Fn-EDA potentiates phenotypic switching in human and mouse aortic SMCs and neointimal hyperplasia in the mouse. We suggest that targeting Fn-EDA could be explored as a potential therapeutic strategy to reduce neointimal hyperplasia.

Authors

Manish Jain, Nirav Dhanesha, Prakash Doddapattar, Mehul R. Chorawala, Manasa K. Nayak, Anne Cornelissen, Liang Guo, Aloke V. Finn, Steven R. Lentz, Anil K. Chauhan

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Figure 6

TLR4 contributes to Fn-EDA–mediated SMC proliferation and migration.

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TLR4 contributes to Fn-EDA–mediated SMC proliferation and migration. (A)...
(A) SMCs from Apoe–/– mice were stimulated with PDGF-BB for 24 hours, and cell extracts were immunoprecipitated (IP) with either anti-TLR4 or anti–Fn-EDA antibody and immunoblotted by anti–Fn-EDA. (B) Serum-starved aortic SMCs from Fn-EDA–/– Apoe–/– and Fn-EDA–/– TLR4–/– Apoe–/– mice were stimulated with either cFn-EDA (20 μg/mL) or pFn lacking EDA (20 μg/mL) for 24 hours. The left panels show representative BrdU-positive cells costained with αSMA (green) and Hoechst (blue). Scale bars: 50 μm. The right panel shows the quantification of BrdU-positive cells to the total number of cells (n = 5–6 per group). (C) Quantitative data of cell cycle distribution in aortic SMCs treated with either cFn-EDA or pFn lacking EDA (n = 6–8 per group). (D) The left panels show representative phase-contrast images of SMC migration in the scratch assay. The right panel shows quantification of the migrated area (n = 6–7 per group). Scale bars: 500 μm. Values are represented as mean ± SEM. Statistical analysis: 1-way ANOVA with Bonferroni’s post hoc test.