title: Transcriptional profiling of epidermal keratinocytes: comparison of genes expressed in skin, cultured keratinocytes, and reconstituted epidermis, using large DNA microarrays.
abstract: Epidermal keratinocytes are complex cells that create a unique three-dimensional (3-D) structure, differentiate through a multistage process, and respond to extracellular stimuli from nearby cells. Consequently, keratinocytes express many genes, i.e., have a relatively large "transcriptome." To determine which of the expressed genes are innate to keratinocytes, which are specific for the differentiation and 3-D architecture, and which are induced by other cell types, we compared the transcriptomes of skin from human subjects, differentiating 3-D reconstituted epidermis, cultured keratinocytes, and nonkeratinocyte cell types. Using large oligonucleotide microarrays, we analyzed five or more replicates of each, which yielded statistically consistent data and allowed identification of the differentially expressed genes. Epidermal keratinocytes, unlike other cells, express many proteases and protease inhibitors and genes that protect from UV light. Skin specifically expresses a higher number of receptors, secreted proteins, and transcription factors, perhaps influenced by the presence of nonkeratinocyte cell types. Surprisingly, mitochondrial proteins were significantly suppressed in skin, suggesting a low metabolic rate. Three-dimensional samples, skin and reconstituted epidermis, are similar to each other, expressing epidermal differentiation markers. Cultured keratinocytes express many cell-cycle and DNA replication genes, as well as integrins and extracellular matrix proteins. These results define innate, architecture-specific, and cell-type-regulated genes in epidermis.
authors.affiliation: Department of Dermatology, New York University School of Medicine, New York, USA.
authors.forename: Alix
authors.initials: A
authors.lastname: Gazel
authors.forename: Patricia
authors.initials: P
authors.lastname: Ramphal
authors.forename: Martin
authors.initials: M
authors.lastname: Rosdy
authors.forename: Bart
authors.initials: B
authors.lastname: De Wever
authors.forename: Carine
authors.initials: C
authors.lastname: Tornier
authors.forename: Nadia
authors.initials: N
authors.lastname: Hosein
authors.forename: Brian
authors.initials: B
authors.lastname: Lee
authors.forename: Marjana
authors.initials: M
authors.lastname: Tomic-Canic
authors.forename: Miroslav
authors.initials: M
authors.lastname: Blumenberg
mesh_terms: D000465:Algorithms; D002478:Cells, Cultured; D000078404:Epidermal Cells; D004817:Epidermis / Q000502:physiology*; D015870:Gene Expression / Q000502:physiology; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000502:physiology*; D020411:Oligonucleotide Array Sequence Analysis; D012984:Software; D014158:Transcription, Genetic / Q000502:physiology