Project description:MED1 (Mediator complex subunit 1) is expressed by human epidermal keratinocytes and functions as a coactivator of several transcription factors. To elucidate the role of MED1 in keratinocytes, we established keratinocyte-specific MED1-null (MED1epi-/-) mice using the K5Cre-LoxP system. To elucidate the mechanism(s) underlying abnormalities of keratinocytes derived from MED1epi-/- mice, we compared the gene expression patterns of MED1epi-/--derived keratinocytes with their wild type counterparts by microarray analysis.
Project description:Transcriptional coactivator Mediator complex facilitates transcription of various transcription factors. Previously, we have generated Med1 conditional null mice, where a critical subunit of Mediator, Med1, is removed from keratinocytes. Here we present evidence that ablation of Med1 accelerated epidermal regeneration after injury. As bulge keratinocyte stem cells are important contributors to regenerate epidermis, we first analyzed properties of stem cells in Med1 null mice. BrdU long retaining analysis revealed that deletion of Med1 still maintained quiescence of bulge keratinocyte stem cells, despite of general hyperplasia observed in Med1 deficient keratinocytes. Gene expression analysis demonstrated that a series of niche matrix proteins decreased in Med1 deficient keratinocytes. In contrast, the expression of stem cell marker Sox9 was not altered, suggesting stem cells are present but activated because of abnormal niche surrounding stem cells. In addition, Med1 deletion suppressed injury induced inflammatory reaction, which indirectly regulates epidermal regeneration. We also indicated that TGFβ1 significantly decreased in both bulge and epidermal keratinocytes upon Med1 deletion. Our study demonstrates that coactivator Med1 has a critical role to maintain bulge stem cells and epidermal regeneration presumably through regulation in TGFβ signaling. n=4 WT and KO (each sample contain RNA from one mouse)
Project description:Transcriptional coactivator Mediator complex facilitates transcription of various transcription factors. Previously, we have generated Med1 conditional null mice, where a critical subunit of Mediator, Med1, is removed from keratinocytes. Here we present evidence that ablation of Med1 accelerated epidermal regeneration after injury. As bulge keratinocyte stem cells are important contributors to regenerate epidermis, we first analyzed properties of stem cells in Med1 null mice. BrdU long retaining analysis revealed that deletion of Med1 still maintained quiescence of bulge keratinocyte stem cells, despite of general hyperplasia observed in Med1 deficient keratinocytes. Gene expression analysis demonstrated that a series of niche matrix proteins decreased in Med1 deficient keratinocytes. In contrast, the expression of stem cell marker Sox9 was not altered, suggesting stem cells are present but activated because of abnormal niche surrounding stem cells. In addition, Med1 deletion suppressed injury induced inflammatory reaction, which indirectly regulates epidermal regeneration. We also indicated that TGFβ1 significantly decreased in both bulge and epidermal keratinocytes upon Med1 deletion. Our study demonstrates that coactivator Med1 has a critical role to maintain bulge stem cells and epidermal regeneration presumably through regulation in TGFβ signaling. n=3 WT and KO (each group contains keratinocytes isolated from adult skins excised from 2 mice)
Project description:Transcriptional coactivator Mediator complex facilitates transcription of various transcription factors. Previously, we have generated Med1 conditional null mice, where a critical subunit of Mediator, Med1, is removed from keratinocytes. Here we present evidence that ablation of Med1 accelerated epidermal regeneration after injury. As bulge keratinocyte stem cells are important contributors to regenerate epidermis, we first analyzed properties of stem cells in Med1 null mice. BrdU long retaining analysis revealed that deletion of Med1 still maintained quiescence of bulge keratinocyte stem cells, despite of general hyperplasia observed in Med1 deficient keratinocytes. Gene expression analysis demonstrated that a series of niche matrix proteins decreased in Med1 deficient keratinocytes. In contrast, the expression of stem cell marker Sox9 was not altered, suggesting stem cells are present but activated because of abnormal niche surrounding stem cells. In addition, Med1 deletion suppressed injury induced inflammatory reaction, which indirectly regulates epidermal regeneration. We also indicated that TGFβ1 significantly decreased in both bulge and epidermal keratinocytes upon Med1 deletion. Our study demonstrates that coactivator Med1 has a critical role to maintain bulge stem cells and epidermal regeneration presumably through regulation in TGFβ signaling. n=3 WT and KO (each sample contain RNA isolated from wounded or nonwounded skins excised from 3 mice)
Project description:Transcriptional coactivator Mediator complex facilitates transcription of various transcription factors. Previously, we have generated Med1 conditional null mice, where a critical subunit of Mediator, Med1, is removed from keratinocytes. Here we present evidence that ablation of Med1 accelerated epidermal regeneration after injury. As bulge keratinocyte stem cells are important contributors to regenerate epidermis, we first analyzed properties of stem cells in Med1 null mice. BrdU long retaining analysis revealed that deletion of Med1 still maintained quiescence of bulge keratinocyte stem cells, despite of general hyperplasia observed in Med1 deficient keratinocytes. Gene expression analysis demonstrated that a series of niche matrix proteins decreased in Med1 deficient keratinocytes. In contrast, the expression of stem cell marker Sox9 was not altered, suggesting stem cells are present but activated because of abnormal niche surrounding stem cells. In addition, Med1 deletion suppressed injury induced inflammatory reaction, which indirectly regulates epidermal regeneration. We also indicated that TGFβ1 significantly decreased in both bulge and epidermal keratinocytes upon Med1 deletion. Our study demonstrates that coactivator Med1 has a critical role to maintain bulge stem cells and epidermal regeneration presumably through regulation in TGFβ signaling.
Project description:Transcriptional coactivator Mediator complex facilitates transcription of various transcription factors. Previously, we have generated Med1 conditional null mice, where a critical subunit of Mediator, Med1, is removed from keratinocytes. Here we present evidence that ablation of Med1 accelerated epidermal regeneration after injury. As bulge keratinocyte stem cells are important contributors to regenerate epidermis, we first analyzed properties of stem cells in Med1 null mice. BrdU long retaining analysis revealed that deletion of Med1 still maintained quiescence of bulge keratinocyte stem cells, despite of general hyperplasia observed in Med1 deficient keratinocytes. Gene expression analysis demonstrated that a series of niche matrix proteins decreased in Med1 deficient keratinocytes. In contrast, the expression of stem cell marker Sox9 was not altered, suggesting stem cells are present but activated because of abnormal niche surrounding stem cells. In addition, Med1 deletion suppressed injury induced inflammatory reaction, which indirectly regulates epidermal regeneration. We also indicated that TGFβ1 significantly decreased in both bulge and epidermal keratinocytes upon Med1 deletion. Our study demonstrates that coactivator Med1 has a critical role to maintain bulge stem cells and epidermal regeneration presumably through regulation in TGFβ signaling.
Project description:Transcriptional coactivator Mediator complex facilitates transcription of various transcription factors. Previously, we have generated Med1 conditional null mice, where a critical subunit of Mediator, Med1, is removed from keratinocytes. Here we present evidence that ablation of Med1 accelerated epidermal regeneration after injury. As bulge keratinocyte stem cells are important contributors to regenerate epidermis, we first analyzed properties of stem cells in Med1 null mice. BrdU long retaining analysis revealed that deletion of Med1 still maintained quiescence of bulge keratinocyte stem cells, despite of general hyperplasia observed in Med1 deficient keratinocytes. Gene expression analysis demonstrated that a series of niche matrix proteins decreased in Med1 deficient keratinocytes. In contrast, the expression of stem cell marker Sox9 was not altered, suggesting stem cells are present but activated because of abnormal niche surrounding stem cells. In addition, Med1 deletion suppressed injury induced inflammatory reaction, which indirectly regulates epidermal regeneration. We also indicated that TGFβ1 significantly decreased in both bulge and epidermal keratinocytes upon Med1 deletion. Our study demonstrates that coactivator Med1 has a critical role to maintain bulge stem cells and epidermal regeneration presumably through regulation in TGFβ signaling.
Project description:MED1 (Mediator complex subunit 1) is expressed by human epidermal keratinocytes and functions as a coactivator of several transcription factors. To elucidate the role of MED1 in keratinocytes, we established keratinocyte-specific MED1-null (MED1epi-/-) mice using the K5Cre-LoxP system. To elucidate the mechanism(s) underlying abnormalities of keratinocytes derived from MED1epi-/- mice, we compared the gene expression patterns of MED1epi-/--derived keratinocytes with their wild type counterparts by microarray analysis. Generation of the MED1 conditional null mutation in epidermal keratinocytes and cell culture: MED1flox/flox mice (Jia et al, J Biol Chem 279:24427. 2004) were mated with K5Cre mice (Tarutani et al, Proc Natl Acad Sci U S A 94:7400. 1997) to generate F1 K5Cre+;MED1flox/+ mice. The K5Cre+;MED1flox/+ mice were then mated with MED1flox/flox mice to generate K5Cre+;MED1flox/flox mice (MED1epi-/-). Mice were screened for presence of the transgene by PCR using specific primers for the floxed MED1 gene and the human K5 gene according to the previous reports. Skin of newborn mice was excised after the mice were sacrificed with excessive anesthetic and were treated with dispase followed by trypsin to separate the epidermis from the dermis. Keratinocytes were seeded on type I collagen coated dishes, and were cultured in CnT07 conditioned culture medium (CELLnTEC, Bern, Switzerland). Keratinocytes were used for the experiment as a primary culture. All animal studies were conducted according to protocols approved by the Institutional Animal Care and Use Committee at Osaka University. Microarray analysis: For comprehensive comparison of gene expression patterns between keratinocytes derived from MED1epi-/- and from WT mice, microarray analysis was used. Total RNAs were extracted using an RNeasy kit (Qiagen, San Diego, CA). Then, 2μg total RNA was reverse transcribed to cDNA with T7 oligo d(T) primer (Affymetrix, Santa Clara, CA). The cDNA synthesis products were used for in vitro transcription reactions containing T7 RNA polymerase and biotinylated nucleotide analogue (pheudouridine base) cRNAs. The labeled cRNA products were then fragmented and loaded onto GeneChip(R) Mouse Genome 430 2.0 arrays (Affymetrix), and were hybridized according to the manufacturer’s protocol. Streptavidin-Phycoerythrin (Molecular Probes) was used as the fluorescent conjugate to detect hybridized target sequences. Raw intensity data from the GeneChip array were analyzed by GeneChip Operating Software (Affymetrix).
Project description:Epidermal lineages and injury induced regeneration are controlled by transcriptional programs coordinating cellular signaling and epigenetic regulators, but the mechanism remains unclear. Previous studies showed that conditional deletion of the transcriptional coactivator Mediator 1 (Med1) changes epidermal lineages and accelerates wound re-epithelialization. Here, we studied a molecular mechanism by which Med1 facilitates these processes, in particular, by focusing on TGFb signaling through genome wide transcriptome analysis. The expression of the TGF ligands (Tgfb1/b2) and their downstream target genes is decreased in both normal and wounded Med1 null skin. Med1 silencing in cultured keratinocytes likewise reduces the expression of the ligands (TGFb1/b2) and diminishes activity of TGFb signaling as shown by decreased p-Smad2/3. Silencing Med1 increases keratinocyte proliferation and migration in vitro. Epigenetic studies using chromatin immuno-precipitation and next generation DNA sequencing reveals that Med1 regulates transcription of TGFb components by forming large clusters of enhancers called super-enhancers at the regulatory regions of the TGFb ligand and SMAD3 genes. These results demonstrate that Med1 is required for the maintenance of the TGFb signaling pathway. Finally, we show that pharmacological inhibition of TGFb signaling enhances epidermal lineages and accelerates wound re-epithelialization in skin similar to that seen in the Med1 null mice, providing new insights into epidermal regeneration.
Project description:Analysis of induced keratinocyte stem cells from male/female urine cells (MiKSC/FiKSC) by defined transcription factors vs. foreskin derived primary human neonatal epidermal keratinocytes (pKC) and male/female urine cells (MUC/FUC). Results provide insight into molecular similarities between induced keratinocyte stem cells and human foreskin derived primary human neonatal epidermal keratinocytes.