title: Transforming growth factor-beta receptor II is preferentially expressed in the companion layer of the human anagen hair follicle.
abstract: BACKGROUND
  Transforming growth factor (TGF)-beta is a multifunctional growth factor with multiple roles in skin including hair follicle development and cycling, where it regulates cell proliferation, differentiation and apoptosis, as well as in wound healing. While TGF-beta receptor I (TGF-beta RI) and receptor II (TGF-beta RII) expression helps define early human hair follicle morphogenesis, expression in the adult human hair follicle remains to be established.
  
  
  OBJECTIVE
  To assess TGF-beta receptor expression in human scalp anagen hair follicles.
  
  
  METHODS
  Immunohistochemical and double immunofluorescence analysis of TGF-beta RI and RII was conducted on frozen sections of haired human scalp obtained from 10 healthy individuals.
  
  
  RESULTS
  TGF-beta RI expression was detected in the outer root sheath of anagen hair follicles while TGF-beta RII was expressed almost exclusively in the companion layer of inner root sheath and less so in premedulla keratinocytes. Both receptors were colocalized in the companion layer of the proximal and mid follicle.
  
  
  CONCLUSIONS
  The well-described role of TGF-beta in keratinocyte apoptosis during catagen is likely to involve anagen-specific hair follicle components including the companion layer, as this layer provides the slippage plane supporting the inner root sheath and hair shaft as they ascend to the skin surface. Results of this study suggest that the colocalization of TGF-beta RI/RII complexes at the companion layer would facilitate TGF-beta signalling at this site to regulate apoptosis of the companion layer keratinocytes, facilitating shrinkage/contraction of this cell layer during hair follicle regression/catagen.
authors.affiliation: Medical Biosciences Research, School of Life Sciences, University of Bradford, Bradford BD7 1DP, U.K.
authors.forename: H M
authors.initials: HM
authors.lastname: Sowden
authors.forename: R O S
authors.initials: RO
authors.lastname: Karoo
authors.forename: D J
authors.initials: DJ
authors.lastname: Tobin
mesh_terms: D017209:Apoptosis / Q000502:physiology; D005260:Female; D005455:Fluorescent Antibody Technique / Q000379:methods; D018859:Hair Follicle / Q000378:metabolism*; D006801:Humans; D008297:Male; D017346:Protein Serine-Threonine Kinases; D000077294:Receptor, Transforming Growth Factor-beta Type II; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism*; D012535:Scalp / Q000378:metabolism*
chemical_list: D018125:Receptors, Transforming Growth Factor beta; D017346:Protein Serine-Threonine Kinases; D000077294:Receptor, Transforming Growth Factor-beta Type II