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Therapeutic MK2 inhibition blocks pathological vascular smooth muscle cell phenotype switch
J. William Tierney, … , Colleen M. Brophy, Craig L. Duvall
J. William Tierney, … , Colleen M. Brophy, Craig L. Duvall
Published October 8, 2021
Citation Information: JCI Insight. 2021;6(19):e142339. https://doi.org/10.1172/jci.insight.142339.
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Research Article Vascular biology

Therapeutic MK2 inhibition blocks pathological vascular smooth muscle cell phenotype switch

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Abstract

Vascular procedures, such as stenting, angioplasty, and bypass grafting, often fail due to intimal hyperplasia (IH), wherein contractile vascular smooth muscle cells (VSMCs) dedifferentiate to synthetic VSMCs, which are highly proliferative, migratory, and fibrotic. Previous studies suggest MAPK-activated protein kinase 2 (MK2) inhibition may limit VSMC proliferation and IH, although the molecular mechanism underlying the observation remains unclear. We demonstrated here that MK2 inhibition blocked the molecular program of contractile to synthetic dedifferentiation and mitigated IH development. Molecular markers of the VSMC contractile phenotype were sustained over time in culture in rat primary VSMCs treated with potent, long-lasting MK2 inhibitory peptide nanopolyplexes (MK2i-NPs), a result supported in human saphenous vein specimens cultured ex vivo. RNA-Seq of MK2i-NP–treated primary human VSMCs revealed programmatic switching toward a contractile VSMC gene expression profile, increasing expression of antiinflammatory and contractile-associated genes while lowering expression of proinflammatory, promigratory, and synthetic phenotype–associated genes. Finally, these results were confirmed using an in vivo rabbit vein graft model where brief, intraoperative treatment with MK2i-NPs decreased IH and synthetic phenotype markers while preserving contractile proteins. These results support further development of MK2i-NPs as a therapy for blocking VSMC phenotype switch and IH associated with cardiovascular procedures.

Authors

J. William Tierney, Brian C. Evans, Joyce Cheung-Flynn, Bo Wang, Juan M. Colazo, Monica E. Polcz, Rebecca S. Cook, Colleen M. Brophy, Craig L. Duvall

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Figure 1

MK2i-NPs increase cell uptake and endosomal escape of MK2i in A7r5 cells while maintaining bioactivity.

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MK2i-NPs increase cell uptake and endosomal escape of MK2i in A7r5 cells...
A7r5 cells were incubated for 2 hours with vehicle control (no treatment, NT) or 50 μM MK2i or MK2i-NPs50:5Lyo made with MK2i conjugated with Alexa Fluor 488. (A) After 2 hours, A7r5s were imaged under fluorescence microscopy to confirm uptake of MK2i-488. (B) Flow cytometry was used to quantify cell uptake of MK2i, and MFI for 3 replicates was quantified. (C) A7r5 cells engineered to express YFP-Gal8 were treated with 50 μM MK2i-488 or MK2i-NPs50:5Lyo and imaged to visualize endosomal disruption 3 hours after treatment. (D) The total Gal8-positive pixels were normalized to cell number for 8 replicates. (E) A7r5 cells were treated with 50 μM MK2i or MK2i-NPs (50 μM MK2i and 2.5 μM PPAA) and cultured for 24 hours after treatment prior to LPA stimulation and protein harvesting for Western blot analysis of CREB phosphorylation. n = 3. All statistics were determined using 1-way ANOVA and Tukey’s multiple-comparison test. Scale bars: 50 μm.

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ISSN 2379-3708

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