title: Hydrogen peroxide-induced cell death in normal human keratinocytes is differentiation dependent.
abstract: More than other tissues, skin is exposed to numerous external stresses generating ROS that, in addition to endogenous oxygen radicals, cause keratinocyte alterations and contribute in part to photocarcinogenesis and aging. Recent evidence suggests a differentiation-dependent susceptibility of keratinocytes to apoptosis. We explored hydrogen peroxide-induced cell death in normal human keratinocytes according to their differentiation. On H(2)O(2)-exposed skin explants, caspase-3 was strongly activated in basal keratinocytes double stained with beta(1) integrin, whereas DNA fragmentation occurred in suprabasal cells only without caspase-3 activation. In addition, isolated basal keratinocytes, selected by adhesion to type IV collagen, were more sensitive than nonadherent cells to H(2)O(2)-induced apoptosis with regard to mitochondrial transmembrane potential (Deltapsi(mt)) collapse and membrane integrity. Similarly, necrotic/late apoptotic cells were present at low levels only in the adherent epidermal population. Furthermore, in primary cultures of undifferentiated keratinocytes H(2)O(2)-induced cell death appeared via a mitochondrial failure. Deltapsi(mt) collapse was associated with a strong early activation of the initiatory caspase-8, then the executive caspase-3, and, to a lesser extent, the inflammatory caspase-1. Finally, undifferentiated basal cells possess a higher sensitivity than differentiated suprabasal cells to H(2)O(2)-induced cell death, and apoptosis in human keratinocytes occurs via different pathways depending on the cell's differentiation state.
authors.affiliation: LVMH-Recherches, Laboratoires R&D, Branche Parfums-Cosmétiques, 185 avenue de Verdun, 45804 Saint-Jean de Braye Cedex, France. thomas.zuliani@unilim.fr
authors.forename: Thomas
authors.initials: T
authors.lastname: Zuliani
authors.forename: Vincent
authors.initials: V
authors.lastname: Denis
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Noblesse
authors.forename: Sylvianne
authors.initials: S
authors.lastname: Schnebert
authors.forename: Patrice
authors.initials: P
authors.lastname: Andre
authors.forename: Marc
authors.initials: M
authors.lastname: Dumas
authors.forename: Marie-Hélène
authors.initials: MH
authors.lastname: Ratinaud
mesh_terms: D000328:Adult; D017209:Apoptosis / Q000187:drug effects; D020170:Caspase 1 / Q000187:drug effects / Q000378:metabolism; D053148:Caspase 3; D053181:Caspase 8; D020169:Caspases / Q000187:drug effects / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology; D016923:Cell Death / Q000187:drug effects; D002454:Cell Differentiation / Q000502:physiology*; D002478:Cells, Cultured; D024141:Collagen Type IV / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects*; D008875:Middle Aged; D009924:Organ Culture Techniques; D016877:Oxidants / Q000494:pharmacology; D012867:Skin / Q000166:cytology / Q000187:drug effects; D013997:Time Factors
chemical_list: D024141:Collagen Type IV; D016877:Oxidants; D006861:Hydrogen Peroxide; C505407:CASP3 protein, human; C505530:CASP8 protein, human; D053148:Caspase 3; D053181:Caspase 8; D020169:Caspases; D020170:Caspase 1