In adult skin, each hair follicle contains a reservoir of stem cells (the bulge), which can be mobilized to regenerate the new follicle with each hair cycle and to reepithelialize epidermis during wound repair. Here we report new methods that permit their clonal analyses and engraftment and demonstrate the two defining features of stem cells, namely self-renewal and multi-potency. We also show that, within the bulge, there are two distinct populations, one of which maintains basal lamina contact and temporally precedes the other, which is suprabasal and arises only after the start of the first postnatal hair cycle. This spatial distinction endows them with discrete transcriptional programs, but surprisingly, both populations are growth inhibited in the niche but can self-renew in vitro and make epidermis and hair when grafted. These findings suggest that the niche microenvironment imposes intrinsic stemness features without restricting the establishment of epithelial polarity and changes in gene expression.
Self-renewal, multipotency, and the existence of two cell populations within an epithelial stem cell niche.
Specimen part
View SamplesSweat glands are abundant glands of our body and essential for thermoregulation. Like mammary glands, they originate from epidermal progenitors. However, they display few signs of cellular turnover, and whether they have stem cells and tissue regenerative capacity remain largely unexplored. Here we address these issues. Using lineage-tracing, we identify multipotent progenitors in sweat duct that transition to unipotency after developing the sweat gland. In characterizing four adult stem cell populations of glandular skin, we show that they display distinct regenerative capabilities and remain unipotent when healing epidermal, myoepithelial-specific and luminal-specific injuries. We devise purification schemes, isolate and transcriptionally profile progenitors. Exploiting molecular differences between sweat and mammary glands, we show that only some progenitors regain multipotency to produce de novo ductal and glandular structures, but that these can retain their identity even within certain foreign microenvironments. Our findings provide new concepts about glandular stem cells and sweat gland biology.
Identification of stem cell populations in sweat glands and ducts reveals roles in homeostasis and wound repair.
Sex, Specimen part
View SamplesThe skin interfollicular epidermis (IFE) is the first barrier against the external environment and its maintenance is critical for survival. Two seemingly opposite theories have been proposed to explain IFE homeostasis. One posits that IFE is maintained by a long-lived slow-cycling stem cell (SC) population that give rise to short-lived transit-amplifying (TA) cell progeny, while the other suggests that homeostasis is achieved by a single committed progenitor (CP) that balances stochastic fate. Here, we probed the cellular heterogeneity within the IFE using two different inducible CREER targeting IFE progenitors. Quantitative analysis of clonal fate data and proliferation dynamics demonstrate the existence of two distinct proliferative cell compartments composed of slow-cycling SC and CP, both of which undergo population asymmetric self-renewal. However, following wounding, only SCs contribute substantially to the repair and long-term regeneration of the tissue, while CP cells make a minimal and transient contribution.
Distinct contribution of stem and progenitor cells to epidermal maintenance.
Specimen part
View SamplesThis study was designed to investigate the transcripts that are regulated by Twist1 in skin tymor epithelial cells in a p53-dependent and independent manner. To this aim, Tumor epithelial cells from primary mouse skin tumors of different genotypes were FACS sorted and analyzed by microarray.
Different levels of Twist1 regulate skin tumor initiation, stemness, and progression.
Specimen part, Treatment
View SamplesEpithelial to mesenchymal transition (EMT) in cancer cells has been associated with metastasis, stemness and resistance to therapy. The reason why some tumors undergo EMT and other not might reflect intrinsic properties of their cell of origin, although this possibility is largely unexplored. By targeting the same oncogenic mutations to discrete skin compartments, we show cell type-specific chromatin and transcriptional states differentially prime tumors to EMT. Squamous cell carcinomas (SCCs) derived from intrafollicular epidermis (IFE) are generally well-differentiated, while hair follicle (HF) stem cell-derived SCCs frequently exhibit EMT, efficiently form secondary tumors, and possess increased metastatic potential. Transcriptional and epigenomic profiling revealed IFE and HF tumor-initiating cells possess distinct chromatin landscapes and gene regulatory networks associated with tumorigenesis and EMT that correlate with accessibility of key epithelial and EMT transcription factor binding sites. These findings highlight the importance of chromatin states and transcriptional priming in dictating tumor phenotypes and EMT.
Cell-Type-Specific Chromatin States Differentially Prime Squamous Cell Carcinoma Tumor-Initiating Cells for Epithelial to Mesenchymal Transition.
Sex, Specimen part, Treatment
View SamplesEpithelial to mesenchymal transition (EMT) in cancer cells has been associated with metastasis, stemness and resistance to therapy. The reason why some tumors undergo EMT and other not might reflect intrinsic properties of their cell of origin, although this possibility is largely unexplored. By targeting the same oncogenic mutations to discrete skin compartments, we show cell type-specific chromatin and transcriptional states differentially prime tumors to EMT. Squamous cell carcinomas (SCCs) derived from intrafollicular epidermis (IFE) are generally well-differentiated, while hair follicle (HF) stem cell-derived SCCs frequently exhibit EMT, efficiently form secondary tumors, and possess increased metastatic potential. Transcriptional and epigenomic profiling revealed IFE and HF tumor-initiating cells possess distinct chromatin landscapes and gene regulatory networks associated with tumorigenesis and EMT that correlate with accessibility of key epithelial and EMT transcription factor binding sites. These findings highlight the importance of chromatin states and transcriptional priming in dictating tumor phenotypes and EMT.
Cell-Type-Specific Chromatin States Differentially Prime Squamous Cell Carcinoma Tumor-Initiating Cells for Epithelial to Mesenchymal Transition.
Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Sox9 Controls Self-Renewal of Oncogene Targeted Cells and Links Tumor Initiation and Invasion.
Specimen part
View SamplesSox9 is a transcription factor expressed in most solid tumors. However, the molecular mechanisms underlying Sox9 function during tumorigenesis remain unclear. Here, using a genetic mouse model of basal cell carcinoma (BCC), the most frequent cancer in human, we show that Sox9 is expressed from the earliest step of tumor formation in a Wnt/-catenin dependent manner. Deletion of Sox9 together with the constitutive activation of Hedgehog (HH) signaling completely prevents BCC formation and leads to a progressive loss of oncogene expressing cells. Transcriptional profiling of oncogene expressing cells with Sox9 deletion, combined with in vivo ChIP-sequencing uncovers a cancer-specific gene network regulated by Sox9 that promotes stemness, extracellular matrix (ECM) deposition and cytoskeleton remodeling while repressing epidermal differentiation. Our study identifies the molecular mechanisms regulated by Sox9 that links tumor initiation and invasion.
Sox9 Controls Self-Renewal of Oncogene Targeted Cells and Links Tumor Initiation and Invasion.
Specimen part
View SamplesTranscriptional profile of control and VEGF overexpressing FACS-isolated CD34+ Cancer stem cells from DMBA/TPA induced skin tumours
A vascular niche and a VEGF-Nrp1 loop regulate the initiation and stemness of skin tumours.
No sample metadata fields
View SamplesBasal cell carcinoma initiating cells undergo profound and rapid reprogramming into embryonic hair follicle progenitor like fate upon SmoM2 expression. Activation of Wnt/-catenin signaling pathways is required in a cell autonomous manner for the reprogramming of adult IFE progenitors into EHFP-like fate as well as for tumor initiation.
Adult interfollicular tumour-initiating cells are reprogrammed into an embryonic hair follicle progenitor-like fate during basal cell carcinoma initiation.
Specimen part
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