title: Suppression of keratinocyte stratification by a dominant negative JunB mutant without blocking cell proliferation.
abstract: Keratinocytes make a stratified epidermoid structure when cultured at an air-liquid interface. The three-dimensional (3D) culture of keratinocytes has been successfully used for more than 25 years, but it is still unclear why keratinocytes stratify in response to air exposure. AP-1 proteins are ubiquitous transcription factors that regulate many biological processes, including cell proliferation, differentiation and apoptosis. We established HaCaT-JunBDeltaN, a human keratinocyte cell line that expressed a mutant JunB with a dominant negative effect on AP-1 activity. Stratification of HaCaT-JunBDeltaN cells was markedly suppressed in a 3D culture condition, in which HaCaT cells stratified similarly to stratified squamous epithelia. However, HaCaT-JunBDeltaN cells had proliferation activities that were closely equivalent to those of HaCaT cells, under both two-dimensional (2D) and 3D culture conditions. To screen for the candidate gene responsible for the different stratification ability, we examined the gene expression profile of HaCaT cells before and after air exposure. Several genes with an antioxidative function, such as aldo-keto reductase and selenoprotein P were highly expressed after air exposure in HaCaT cells but not in HaCaT-JunBDeltaN cells. Our findings indicate the presence of a novel role of AP-1 activity when HaCaT cells make a stratified epidermoid structure under 3D culture conditions.
authors.affiliation: Department of Experimental Pathology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan.
authors.forename: Dai
authors.initials: D
authors.lastname: Ikebe
authors.forename: Bei
authors.initials: B
authors.lastname: Wang
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Suzuki
authors.forename: Mitsuyasu
authors.initials: M
authors.lastname: Kato
mesh_terms: D001483:Base Sequence; D002455:Cell Division; D002460:Cell Line; D017931:DNA Primers; D005799:Genes, Dominant; D006801:Humans; D007150:Immunohistochemistry; D015603:Keratinocytes / Q000166:cytology*; D009154:Mutation; D016755:Proto-Oncogene Proteins c-jun / Q000235:genetics*; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; D016755:Proto-Oncogene Proteins c-jun