Project description:Targets of Retinoic Acid (RA) and 3,4-didehydroretinoic acid (ddRA) were identified in primary human epidermal keratinocytes grown in the presence of atRA or ddRA for 4 and 24 hours. Retinoids (natural forms and synthetic derivatives of vitamin A) are used as therapeutic agents for numerous skin diseases such as keratinization disorders (e.g. ichthyoses) and psoriasis. Two endogenous ligands for retinoic acid receptors exist, retinoic acid (atRA) and 3,4-didehydroretinoic acid (ddRA). In primary human epidermal keratinocytes many transcriptional targets for atRA are known, whereas the targets for ddRA are unknown. In an attempt to determine the targets, we compared the effect of atRA and ddRA on transcriptional profiles in undifferentiated and differentiating human primary keratinocytes. First, as expected, many genes were induced or suppressed in response to keratinocyte differentiation. Furthermore, the two retinoids affected substantially more genes in differentiated keratinocytes (more than 350) than in proliferating keratinocytes (20). In differentiating keratinocytes markers of cornification were suppressed suggesting a de-differentiating effect by the two retinoids. When comparing the expression profile of atRA to that of ddRA, no differently regulated genes were found. The array analysis also found that a minor number of miRNAs and a large number of non-coding transcripts were changed during differentiation and in response to the two retinoids. Furthermore, the expression of all, except one, genes known to cause autosomal recessive congenital ichthyosis (ARCI) were found to be induced by differentiation. These results comprehensively document that atRA and ddRA exert similar transcriptional changes in keratinocytes and also add new insights into the molecular mechanism influenced by retinoids in the epidermis. Furthermore, it suggests which ARCI patients could benefit from therapy with retinoids. Proliferating and differentiated keratinocytes were harvested after 4 and 24 hours after treatment with atRA, ddRA and vehicle for RNA extraction and hybridization on Affymetrix microarrays. Triplicate samples were generated for each time point and each treatment.
Project description:Targets of Retinoic Acid (RA) and 3,4-didehydroretinoic acid (ddRA) were identified in primary human epidermal keratinocytes grown in the presence of atRA or ddRA for 4 and 24 hours. Retinoids (natural forms and synthetic derivatives of vitamin A) are used as therapeutic agents for numerous skin diseases such as keratinization disorders (e.g. ichthyoses) and psoriasis. Two endogenous ligands for retinoic acid receptors exist, retinoic acid (atRA) and 3,4-didehydroretinoic acid (ddRA). In primary human epidermal keratinocytes many transcriptional targets for atRA are known, whereas the targets for ddRA are unknown. In an attempt to determine the targets, we compared the effect of atRA and ddRA on transcriptional profiles in undifferentiated and differentiating human primary keratinocytes. First, as expected, many genes were induced or suppressed in response to keratinocyte differentiation. Furthermore, the two retinoids affected substantially more genes in differentiated keratinocytes (more than 350) than in proliferating keratinocytes (20). In differentiating keratinocytes markers of cornification were suppressed suggesting a de-differentiating effect by the two retinoids. When comparing the expression profile of atRA to that of ddRA, no differently regulated genes were found. The array analysis also found that a minor number of miRNAs and a large number of non-coding transcripts were changed during differentiation and in response to the two retinoids. Furthermore, the expression of all, except one, genes known to cause autosomal recessive congenital ichthyosis (ARCI) were found to be induced by differentiation. These results comprehensively document that atRA and ddRA exert similar transcriptional changes in keratinocytes and also add new insights into the molecular mechanism influenced by retinoids in the epidermis. Furthermore, it suggests which ARCI patients could benefit from therapy with retinoids.
Project description:Human epidermal keratinocytes undergo tightly controlled program of cell differentiation, leading to the formation of cornified envelope. Primary keratinocytes in vitro, under calcium stimulation mimic the differentiation program observed in vivo. Analysis of the transcription profile of two cell population, such as proliferating cells and differentiating cells helps to discover new genes implicated in that process and to understand the mechanisms of regulation of the keratinocyte differentiation. Primary human keratinocytes were cultured under proliferating (Day 0, sub-confluent cells) and differentiating (seven days of high calcium medium) conditions. As a source of cells, we used normal skin from different body sites: back, foreskin, palmoplantar. RNA extracted from cultured primary human keratinocytes were isolated from five different donors. We compared the expression profiles of proliferating versus differentiating keratinocytes.
Project description:Targets of Retinoic Acid (RA) were identified in primary human epidermal keratinocytes grown in the presence or absence of all-trans retinoic acid for 1, 4, 24, 48 and 72 hours. Targets of Thyroid Hormone (T3) were identified in primary human epidermal keratinocytes grown in the presence or absence of the hormone; same controls as for RA.
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:Targets of Retinoic Acid (RA) were identified in primary human epidermal keratinocytes grown in the presence or absence of all-trans retinoic acid for 1, 4, 24, 48 and 72 hours. Targets of Thyroid Hormone (T3) were identified in primary human epidermal keratinocytes grown in the presence or absence of the hormone; same controls as for RA. Time course, 1, 4, 24, 48 and 72 hours