title: Lysyl oxidase silencing impairs keratinocyte differentiation in a reconstructed-epidermis model.
abstract: Lysyl Oxidase (LOX) is an extracellular enzyme involved in the maturation of connective tissues. It also acts in many cell types as a regulator of cell behaviour and phenotype through intracellular signalling pathways. Recently, LOX was shown to be present in human epidermis where its precise functions remain unclear. We showed here that in confluent monolayer cultures of normal human keratinocytes (KCs) and N/TERT-1-immortalized KCs, LOX expression was induced during the first differentiation steps. Moreover, the silencing of LOX by stable RNA interference disrupted the expression of early differentiation markers. In a reconstructed-epidermis model, LOX silencing did not impair the stratification process nor the formation of the first differentiated layers. However, terminal differentiation was strongly impaired, as shown by a decreased expression of late differentiation proteins and by the absence of stratum corneum. Nonetheless, inhibition of LOX enzymatic activity by β-aminopropionitrile did not affect the differentiation process. Therefore, LOX protein acts during the first steps of KC differentiation and is important for subsequent commitment into terminal differentiation. Taken together, these results suggest that a finely regulated expression of LOX is necessary for normal KC differentiation and thus for maintenance of epidermal homeostasis.
authors.affiliation: Institut de Biologie et de Chimie des Protéines, Centre national de la Recherche Scientifique, Université Lyon 1, Institut Fédératif de Recherches 128, Lyon, France.
authors.forename: Gabrielle S
authors.initials: GS
authors.lastname: Le Provost
authors.forename: Romain
authors.initials: R
authors.lastname: Debret
authors.forename: Valérie
authors.initials: V
authors.lastname: Cenizo
authors.forename: Géraldine
authors.initials: G
authors.lastname: Aimond
authors.forename: Floriane
authors.initials: F
authors.lastname: Pez
authors.forename: Bastien
authors.initials: B
authors.lastname: Kaniewski
authors.forename: Valérie
authors.initials: V
authors.lastname: André
authors.forename: Pascal
authors.initials: P
authors.lastname: Sommer
mesh_terms: D000629:Aminopropionitrile / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D002461:Cell Line, Transformed; D049109:Cell Proliferation; D002470:Cell Survival / Q000235:genetics; D002478:Cells, Cultured; D018920:Coculture Techniques; D004791:Enzyme Inhibitors / Q000494:pharmacology; D000078404:Epidermal Cells; D004817:Epidermis / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology; D000091344:Filaggrin Proteins; D015870:Gene Expression / Q000235:genetics; D006801:Humans; D007381:Intermediate Filament Proteins / Q000235:genetics / Q000378:metabolism; D053550:Keratin-10 / Q000235:genetics / Q000378:metabolism; D015603:Keratinocytes / Q000166:cytology* / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism; D008249:Protein-Lysine 6-Oxidase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D011503:Transglutaminases / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation / Q000235:genetics
chemical_list: D004791:Enzyme Inhibitors; D000091344:Filaggrin Proteins; D007381:Intermediate Filament Proteins; C507493:KRT10 protein, human; D008565:Membrane Proteins; D011498:Protein Precursors; C064554:loricrin; D053550:Keratin-10; D000629:Aminopropionitrile; C032253:involucrin; D008249:Protein-Lysine 6-Oxidase; D011503:Transglutaminases; C105804:transglutaminase 1