Glucocorticoid-mediated induction of caveolin-1 disrupts cytoskeletal organization, inhibits cell migration and re-epithelialization of non-healing wounds

Ivan Jozic,Beatriz Abdo Abujamra,Tongyu C Wikramanayake,Jelena Marjanovic,Irena Pastar,Rivka C Stone,Fotios M Andreopoulos,Robert S Kirsner,Michael H Elliott,Cheyanne R Head,Juan P Musi,Marjana Tomic-Canic

doi:10.1038/s42003-021-02298-5

Ivan Jozic, Beatriz Abdo Abujamra + Show 10 more

Open Access

https://doi.org/10.1038/s42003-021-02298-5

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Abstract

Although impaired keratinocyte migration is a recognized hallmark of chronic wounds, the molecular mechanisms underpinning impaired cell movement are poorly understood. Here, we demonstrate that both diabetic foot ulcers (DFUs) and venous leg ulcers (VLUs) exhibit global deregulation of cytoskeletal organization in genomic comparison to normal skin and acute wounds. Interestingly, we found that DFUs and VLUs exhibited downregulation of ArhGAP35, which serves both as an inactivator of RhoA and as a glucocorticoid repressor. Since chronic wounds exhibit elevated levels of cortisol and caveolin-1 (Cav1), we posited that observed elevation of Cav1 expression may contribute to impaired actin-cytoskeletal signaling, manifesting in aberrant keratinocyte migration. We showed that Cav1 indeed antagonizes ArhGAP35, resulting in increased activation of RhoA and diminished activation of Cdc42, which can be rescued by Cav1 disruption. Furthermore, we demonstrate that both inducible keratinocyte specific Cav1 knockout mice, and MβCD treated diabetic mice, exhibit accelerated wound closure. Taken together, our findings provide a previously unreported mechanism by which Cav1-mediated cytoskeletal organization prevents wound closure in patients with chronic wounds.

Highlights

Impaired keratinocyte migration is a recognized hallmark of chronic wounds, the molecular mechanisms underpinning impaired cell movement are poorly understood
We show that increased production of GCs in diabetic foot ulcers (DFUs) leads to a downregulation of a glucocorticoid receptor repressor ArhGAP35
To assess how are cytoskeletal genes affected in chronic wounds, we utilized Ingenuity Pathway Analysis (IPA) software to compare expression profiles of DFUs to human acute wounds at days 3 and 7 post wounding[25,26]

Summary

Introduction

Impaired keratinocyte migration is a recognized hallmark of chronic wounds, the molecular mechanisms underpinning impaired cell movement are poorly understood. Disruption of Cav[1] (by MβCD) or knockout of Cav[1] (by CRISPR/Cas9) reverses these GC-mediated events We validate these findings functionally in vivo by showing that selective downregulation of Cav[1] in keratinocytes (using KRT14Cav1KO mouse model) accelerates cutaneous reepithelialization in vivo and that Cav[1] disruption reverses delayed wound epithelialization in the db/db mouse wound model. Together, these data provide mechanistic insights regarding Cav1-mediated inhibition of wound closure observed in patients and provide pre-clinical testing for therapeutic interventions targeting by disruption of cholesterol

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