Oral Presentation Hunter Cell Biology Meeting 2022

Accelerated healing of diabetic wounds by efficient recruitment of fibroblasts upon inhibiting a 14-3-3/ROCK regulatory signalling axis (#41)

Zahied Johan 1 , Natasha T Pyne 1 , Natasha Kolesnikoff 1 , Valentina Poltavets 1 , Zahra Esmaeili 1 , Joanna M Woodcock 1 , Angel F Lopez 1 2 , Allison J Cowin 2 3 , Stuart M Pitson 1 2 , Michael S Samuel 1 2
  1. Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, South Australia, Australia
  2. Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, South Australia, Australia
  3. Future Industries Institute, University of South Australia, Adelaide, South Australia, Australia

Wound healing is a complex and highly regulated tissue repair process that if perturbed can result in chronic wounds. Diabetic wounds are in this category, characterised by slow healing which increases the risk of infection. We have previously demonstrated that a protein called 14-3-3ΞΆ regulates wound healing in healthy skin. The 14-3-3 family of proteins is highly conserved, and its members play key roles in many cellular processes by binding phospho-serine or phospho-threonine residues to act as molecular chaperones, adaptor proteins or to regulate protein-protein interactions.

Depleting 14-3-3 using a targeted deletion approach increases signalling through Rho-associated protein kinase (ROCK) at the margins of incisional wounds and accelerates healing in mice (Kular et al 2015).

Here, we have taken advantage of the Leprdb Type II diabetic murine model, which bears inactivating mutations in the Leptin receptor and exhibits delayed wound healing, and a pharmacological inhibitor of 14-3-3 to establish whether inhibiting 14-3-3 accelerates wound re-epithelialisation in diabetic wounds. Full-thickness incisions were made in the dorsal skin of Leprdb mice and wounds were topically treated with 14-3-3 inhibitor RB11. 14-3-3 inhibition by RB11 accelerated wound closure more than two-fold relative to vehicle. We also observed an increase in the ROCK kinase activity in 14-3-3 inhibitor-treated wounds as demonstrated by the 3-fold enhanced phosphorylation of its substrate, Mypt1, compared to that in wounds treated with vehicle control. 14-3-3 inhibition also led to increased fibroblast recruitment to the wound site relative to controls caused by an enhancement of their ability to migrate persistently, which may contribute to the wound healing process. The ECM composition of healed skin in RB11-treated diabetic mice was consistent with that observed in unwounded skin, suggesting that RB11 does not compromise the quality of wound healing

Our observations that induction of the 14-3-3/ROCK inhibitory axis is frequently characteristic of impaired wound healing and that its suppression facilitates fibroblast recruitment and accelerated would healing, suggests new possibilities for treating chronic wounds by targeting this axis.

  1. Kular J, Scheer KG, Pyne NT, Allam AH, Pollard AN, Magenau A, et al. A Negative Regulatory Mechanism Involving 14-3-3zeta Limits Signaling Downstream of ROCK to Regulate Tissue Stiffness in Epidermal Homeostasis. Dev Cell 2015;35(6):759-74.