Stem cell plasticity enables hair regeneration following Lgr5+ cell loss

Nat Cell Biol. 2017 Jun;19(6):666-676. doi: 10.1038/ncb3535. Epub 2017 May 29.

Abstract

Under injury conditions, dedicated stem cell populations govern tissue regeneration. However, the molecular mechanisms that induce stem cell regeneration and enable plasticity are poorly understood. Here, we investigate stem cell recovery in the context of the hair follicle to understand how two molecularly distinct stem cell populations are integrated. Utilizing diphtheria-toxin-mediated cell ablation of Lgr5+ (leucine-rich repeat-containing G-protein-coupled receptor 5) stem cells, we show that killing of Lgr5+ cells in mice abrogates hair regeneration but this is reversible. During recovery, CD34+ (CD34 antigen) stem cells activate inflammatory response programs and start dividing. Pharmacological attenuation of inflammation inhibits CD34+ cell proliferation. Subsequently, the Wnt pathway controls the recovery of Lgr5+ cells and inhibition of Wnt signalling prevents Lgr5+ cell and hair germ recovery. Thus, our study uncovers a compensatory relationship between two stem cell populations and the underlying molecular mechanisms that enable hair follicle regeneration.

MeSH terms

  • Alopecia / genetics
  • Alopecia / metabolism*
  • Alopecia / physiopathology
  • Animals
  • Anti-Inflammatory Agents / pharmacology
  • Antigens, CD34 / metabolism
  • Bone Morphogenetic Proteins / metabolism
  • Cell Plasticity* / drug effects
  • Cell Proliferation* / drug effects
  • Disease Models, Animal
  • Female
  • Genetic Predisposition to Disease
  • Hair Follicle / drug effects
  • Hair Follicle / growth & development
  • Hair Follicle / metabolism*
  • Hair Follicle / pathology
  • Inflammation Mediators / metabolism
  • Male
  • Mice, Knockout
  • Phenotype
  • Receptors, G-Protein-Coupled / deficiency
  • Receptors, G-Protein-Coupled / genetics
  • Receptors, G-Protein-Coupled / metabolism*
  • Regeneration* / drug effects
  • Stem Cells / drug effects
  • Stem Cells / metabolism*
  • Stem Cells / pathology
  • Wnt Signaling Pathway

Substances

  • Anti-Inflammatory Agents
  • Antigens, CD34
  • Bone Morphogenetic Proteins
  • Inflammation Mediators
  • Lgr5 protein, mouse
  • Receptors, G-Protein-Coupled