Differential responses to folic acid in an established keloid fibroblast cell line are mediated by JAK1/2 and STAT3

PLoS One. 2021 Mar 4;16(3):e0248011. doi: 10.1371/journal.pone.0248011. eCollection 2021.

Abstract

Keloids are a type of disordered scar formation which not only show heterogeneity between individuals and within the scar itself, but also share common features of hyperproliferation, abnormal extra-cellular matrix deposition and degradation, as well as altered expression of the molecular markers of wound healing. Numerous reports have established that cells from keloid scars display Warburg metabolism-a form of JAK2/STAT3-induced metabolic adaptation typical of rapidly dividing cells in which glycolysis becomes the predominant source of ATP over oxidative phosphorylation (OxPhos). Using the JAK1/2 inhibitor ruxolitinib, along with cells from patients with STAT3 loss of function (STA3 LOF; autosomal dominant hyper IgE syndrome) we examined the role of JAK/STAT signaling in the hyperproliferation and metabolic dysregulation seen in keloid fibroblasts. Although ruxolitinib inhibited hyperactivity in the scratch assay in keloid fibroblasts, it paradoxically exacerbated the hyper-glycolytic state, possibly by further limiting OxPhos via alterations in mitochondrial phosphorylated STAT3 (pSTAT3Ser727). In healthy volunteer fibroblasts, folic acid exposure recapitulated the exaggerated closure and hyper-glycolytic state of keloid fibroblasts through JAK1/2- and STAT3-dependent pathways. Although additional studies are needed before extrapolating from a representative cell line to keloids writ large, our results provide novel insights into the metabolic consequences of STAT3 dysfunction, suggest a possible role for folate metabolism in the pathogenesis of keloid scars, and offer in vitro pre-clinical data supporting considerations of clinical trials for ruxolitinib in keloid disorder.

Publication types

  • Clinical Trial
  • Research Support, N.I.H., Intramural

MeSH terms

  • Cells, Cultured
  • Fibroblasts / drug effects*
  • Fibroblasts / metabolism
  • Fibroblasts / pathology
  • Folic Acid / pharmacology*
  • Glycolysis / drug effects
  • Humans
  • Janus Kinase 1 / antagonists & inhibitors
  • Janus Kinase 1 / metabolism
  • Janus Kinase 2 / antagonists & inhibitors
  • Janus Kinase 2 / metabolism
  • Keloid / drug therapy
  • Keloid / metabolism*
  • Keloid / pathology
  • Nitriles
  • Protein Kinase Inhibitors / pharmacology*
  • Pyrazoles / pharmacology*
  • Pyrimidines
  • STAT3 Transcription Factor / metabolism
  • Signal Transduction / drug effects
  • Vitamin B Complex / pharmacology*

Substances

  • Nitriles
  • Protein Kinase Inhibitors
  • Pyrazoles
  • Pyrimidines
  • STAT3 Transcription Factor
  • STAT3 protein, human
  • Vitamin B Complex
  • ruxolitinib
  • Folic Acid
  • JAK1 protein, human
  • JAK2 protein, human
  • Janus Kinase 1
  • Janus Kinase 2

Grants and funding

This work was supported by the Intramural Research Program of NIAID and the NIH.