Phenotypic screening identifies hydroxypyridone anti-fungals as novel medicines for the prevention of hypertrophic scars

Eur J Pharmacol. 2022 Dec 15;937:175374. doi: 10.1016/j.ejphar.2022.175374. Epub 2022 Nov 5.

Abstract

Although hypertrophic scarring affects ∼91% of burn patients annually, there is no drug to prevent this common complication. Hypertrophic scars are a result of dysregulated wound healing, characterised by persistent myofibroblast transformation and the excessive accumulation of extracellular matrix (ECM). Due to the multi-mechanistic nature of the scarring process, target-based approaches for identifying novel drugs have failed. Primary human dermal fibroblasts, derived from burn scar tissue, were exposed to transforming growth factor-beta 1 (TGF-β1) to induce myofibroblast transformation. A phenotypic screening assay, measuring alpha-smooth muscle actin (α-SMA) expression, was developed to screen 1,954 approved drugs. Drugs that elicited >80% inhibition of α-SMA expression, and >80% cell viability were progressed as candidate drugs. Anti-myofibroblast activity of the candidates was confirmed before investigating their effects on extracellular matrix (ECM) production and keratinocyte epithelial-mesenchymal transition (EMT). TGF-β1 induced myofibroblast transformation in primary human dermal fibroblasts (Emax = >3 ng/mL). The assay was optimised and validated (Z' = 0.59), before screening 1,954 approved drugs. 90 drugs were identified as hits and hydroxypyridone anti-fungals selected for further testing. Concentration-response curves for these drugs confirmed their concentration-dependent anti-myofibroblast activity (IC50 = 1.4 - 16.7 μM). Hydroxypyridone anti-fungals were also found to successfully reduce ECM production and keratinocyte EMT. This is the first study to screen approved drugs in primary human dermal fibroblasts. Hydroxypyridone anti-fungals were found to prevent myofibroblast transformation, ECM production and keratinocyte EMT suggesting they could be repurposed to prevent hypertrophic scarring.

Keywords: Drug discovery; Fibrosis; Hypertrophic scars; Myofibroblast; Phenotypic screening.

MeSH terms

  • Actins / metabolism
  • Cells, Cultured
  • Cicatrix, Hypertrophic* / drug therapy
  • Cicatrix, Hypertrophic* / metabolism
  • Cicatrix, Hypertrophic* / prevention & control
  • Extracellular Matrix / metabolism
  • Fibroblasts
  • Humans
  • Myofibroblasts / pathology
  • Transforming Growth Factor beta1 / metabolism

Substances

  • Transforming Growth Factor beta1
  • Actins