Epidermal stem cells ensure that skin homeostasis is maintained. In murine skin, epidermal stem cells cluster at specific niches where, under steady-state conditions, they undergo cycles of dormancy and activation1. When cellular replenishment is required, epidermal stem cells egress from the niche and proliferate for a limited number of times to subsequently feed into the differentiated compartment1-3. However, only a subset of stem cells becomes active during each round of morphogenesis, suggesting that stem cells coexist in heterogeneous responsive states within the same niche. Using a circadian clock fluorescent reporter mouse model, we show that the dormant epidermal stem cell niche contains two coexisting populations of stem cells at opposite phases of the clock, which are differentially predisposed to respond to homeostatic cues. In dormant niches, the core molecular clock protein Bmal1 transcriptionally modulates the expression of stem cell regulatory genes, including modulators of Wnt and TGFb, to create two coexisting stem cell populations, one predisposed, and the other less prone, to activation. Unbalancing this equilibrium of epidermal stem cells, through conditional epidermal deletion of Bmal1, resulted in a long-term progressive accumulation of non-responsive stem cells, premature impairment of tissue self-renewal, and a significant reduction in the development of squamous cell carcinomas. Our results indicate that the molecular clock machinery fine-tunes the spatiotemporal behavior of epidermal stem cells within their niche, and that perturbation of this mechanism affects tissue homeostasis and the predisposition to neoplastic transformation. The goals of this study was to compare the transcriptome of epidermal stem cells according to their circadian rhythm phase. We isolated epidermal stem cells (bulge cells; alpha6bright/CD34+ population) from 19 days old Per1-Venus mice and separated them according to Venusbright (clock positive) and Venus dim (clock negative). The goals of this study was to compare the transcriptome of epidermal stem cells in which their circadian rhythm machinery has been perturbed by deleting the gene that encodes for Bmal1. We compared the transcriptomes of basal interfollicular epidermis cells (alpha6 integrin bright/CD34- cells) from the dorsal skin of 1 year old BmalKO mice and their respective control littermates. Each array corresponds to purified cells from approximately 5 mice.
The circadian molecular clock creates epidermal stem cell heterogeneity.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Isolation and in vitro expansion of human colonic stem cells.
Sex, Specimen part, Subject
View SamplesUsing the surface marker EPHB2, we have FACS-purified and profiled stem cell-enriched cell fractions from normal human mucosa, crypt proliferative progenitors and late transient amplifying cells to define a gene expression program specific for normal human colon epithelial stem cells
Isolation and in vitro expansion of human colonic stem cells.
Specimen part, Subject
View SamplesThe transcriptional signature of mucosa of patients with ulcerative colitis (UC) in remission reveals long-lasting changes in the epithelial barrier which persist once the inflammatory response has resolved. In order to investigate if these changes are caused by primary defects in the epithelial cells, we generated in vitro epithelial organoid cultures (EpOCs) from colon samples of non-IBD controls and UC patients.
Alterations in the epithelial stem cell compartment could contribute to permanent changes in the mucosa of patients with ulcerative colitis.
Age, Specimen part
View SamplesUsing EphB2 or the ISC marker Lgr5, we have FACS-purified and profiled intestinal stem cells (ISCs), crypt proliferative progenitors and late transient amplifying cells to define a gene expression program specific for normal ISCs.
The intestinal stem cell signature identifies colorectal cancer stem cells and predicts disease relapse.
Specimen part
View SamplesCarcinoma development in colorectal cancer (CRC) is driven by genetic alterations in numerous signaling pathways. Alterations in the RAS-ERK1/2 pathway are associated with the shortest overall survival for patients after diagnosis of CRC metastatic disease, but how RAS-ERK signaling regulates CRC metastasis is still unknown.
ERK1/2 Signaling Induces Upregulation of ANGPT2 and CXCR4 to Mediate Liver Metastasis in Colon Cancer.
Cell line, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Dependency of colorectal cancer on a TGF-β-driven program in stromal cells for metastasis initiation.
Specimen part, Disease, Disease stage, Treatment, Subject
View SamplesThe survival of isolated metastatic cells and expansion into macroscopic tumour has been recognized as a limiting step for metastasis formation in several cancer types yet the determinants of this process remain largely uncharacterized. In colorectal cancer (CRC), we identify a transcriptional programme in tumour-associated stromal cells, which is intimately linked to a high risk of developing recurrent disease after therapy. A large proportion of CRCs display mutational inactivation of the TGF-beta pathway but paradoxically they are characterized by high TGF-beta production. In these tumours, TGF-beta instructs a transcriptional programme in stromal cells, which confers a high risk of developing metastatic disease.
Dependency of colorectal cancer on a TGF-β-driven program in stromal cells for metastasis initiation.
Specimen part, Disease, Disease stage, Subject
View SamplesThe survival of isolated metastatic cells and expansion into macroscopic tumour has been recognized as a limiting step for metastasis formation in several cancer types yet the determinants of this process remain largely uncharacterized. In colorectal cancer (CRC), we identify a transcriptional programme in tumour-associated stromal cells, which is intimately linked to a high risk of developing recurrent disease after therapy. A large proportion of CRCs display mutational inactivation of the TGF-beta pathway but paradoxically they are characterized by high TGF-beta production. In these tumours, TGF-beta instructs a transcriptional programme in stromal cells, which confers a high risk of developing metastatic disease.
Dependency of colorectal cancer on a TGF-β-driven program in stromal cells for metastasis initiation.
Disease, Disease stage, Subject
View SamplesThe survival of isolated metastatic cells and expansion into macroscopic tumour has been recognized as a limiting step for metastasis formation in several cancer types yet the determinants of this process remain largely uncharacterized. In colorectal cancer (CRC), we identify a transcriptional programme in tumour-associated stromal cells, which is intimately linked to a high risk of developing recurrent disease after therapy. A large proportion of CRCs display mutational inactivation of the TGF-beta pathway but paradoxically they are characterized by high TGF-beta production. In these tumours, TGF-beta instructs a transcriptional programme in stromal cells, which confers a high risk of developing metastatic disease.
Dependency of colorectal cancer on a TGF-β-driven program in stromal cells for metastasis initiation.
Specimen part, Treatment
View Samples