Deletion of Mediator (Med1) induces epidermal fate in dental epithelial stem cells
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ABSTRACT: Cell fates are defined by specific transcriptional program. We developed a mouse model, in which transcriptional program for ectoderm cell fate is altered in tooth and skin. Previously, we showed that genomic deletion of one subunit of Mediator complex, Mediator 1 (Med1) in vivo regenerate ectopic hair in incisors by disrupting Notch mediated enamel epithelial differentiation. However, precise process and molecular mechanism to induce epidermal fate are not clear. Med1 deficient dental epithelial stem cells exerts transcriptional program for skin epithelia reminiscent of the pattern in the skin. Epidermal transcripts were first induced prior to hair genes during dental epithelial differentiation, resemble to the pattern of embryonic developmental process of the skin. Hair genes was specifically induced at the anagen stage synchronized with hair cycling in the skin. Epidermal program was also induced in cultured adult stem cells called dental epithelial stem cell (DESC) that is derived from micro-dissected Med1 KO cervical loop tissues that are essential for continuous regeneration of mouse incisors. Gene expression profiles for the primary DESC with colony forming capability revealed that Med1 deletion suppressed Tgfb signaling by reducing the expression of ligands (Tgfb1, Inhibin ba), receptors and their extracellular targets such as Ctgf. Med1 deletion also induced Tgfb regulated reprogramming transcription factor, Klf4 that also known to drive transcription for epidermal genes. TGFb signaling was also suppressed in Med1 null epidermis in skin, in which epidermal fate was induced in hair follicle keratinocytes. Med1 silencing blocked expression of TGFb1 and suppressed both basal and recombinant TGFb induced Smad2/3 mediated transcription of TGFb target genes in vitro. These results demonstrate that Med1 deletion enhances epidermal transcriptional program in adult stem cells through regulation of TGFb signaling.
ORGANISM(S): Mus musculus
PROVIDER: GSE112884 | GEO | 2018/12/31
REPOSITORIES: GEO
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