title: Potential of human γD-crystallin for hair damage repair: insights into the mechanical properties and biocompatibility.
abstract: OBJECTIVE
  The objective of this work was to develop a new strategy to physically 'repair' chemically damaged hair. Hence the human eye γD-crystallin, a protein from the superfamily characterized structurally by the Greek key motif, was studied. The human γD-crystallin was chosen based on the ability of proteins belonging to this superfamily to be involved in the coating of specific structures. Two crystallins were used on the study, the wild type (Protein Data Bank ID: 1HK0) and the mutant protein. The mutant form was intended to induce a strong and quick protein polymerization as well to have new possible points of anchorage to hair.
  
  
  METHODS
  The ability of both crystallins to bind to damaged hair and even penetrate into its cortex was checked by fluorescence microscopy, confocal microscopy and scanning electron microscopy. Furthermore the reinforcement of hair mechanical resistance, the potential cytotoxic/inflammatory effect of crystallins were studied in order to have a fully comprehension about the protein based formulation.
  
  
  RESULTS
  Although the chemical over-bleaching treatment induced a decrease of 20% on the resistance of the hair, the crystallins which bind and penetrate the hair fibre were able to recover and even to improve its mechanical properties when compared to the virgin hair. Moreover none of the crystallins displayed a toxic effect in fibroblasts for all the range of tested concentrations upon 72 h of exposure. The active aggregation process of mutant crystallin induced an inflammatory response in fibroblasts in the first 24 h of contact, measured by the amount of released pro-inflammatory cytokine IL-6 to the medium. In contrast contact with wild type crystallin did not lead to significant inflammation.
  
  
  CONCLUSIONS
  Outcome from protein formulation characterization supports the hypothesis that the γD-crystallin it is able to recover and improve the mechanical properties of chemical damaged hair. Therefore it can be considered as a very promising strengthening agent for the development of new restorative hair care products.
authors: IBB-Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057, Braga, Portugal; Department of Biology, Centre of Molecular and Environmental Biology (CBMA), Universidade do Minho, Campus de Gualtar, 4710-057, Braga, Portugal.
authors: A
authors: A
authors: Ribeiro
authors: T
authors: T
authors: Matamá
authors: C F
authors: CF
authors: Cruz
authors: A C
authors: AC
authors: Gomes
authors: A M
authors: AM
authors: Cavaco-Paulo
mesh_terms: D001483:Base Sequence; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D006197:Hair / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D006203:Hair Preparations / Q000494:pharmacology*; D006801:Humans; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D008958:Models, Molecular; D008969:Molecular Sequence Data; D013718:Tensile Strength; D038222:gamma-Crystallins / Q000494:pharmacology*
chemical_list: C504903:CRYGD protein, human; D006203:Hair Preparations; D038222:gamma-Crystallins
keywords: Greek key motif; hair treatment; human crystallin; mechanical properties improvement; over bleached hair