Gene expression profile of hair follicle stem cells (HFSCs) isolated from wild type and homozygous Dab2 cKO (Dab2 Fl/Fl) mice at postnatal day 35
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ABSTRACT: Disabled 2 is an endocytic adaptor protein known to regulate various signaling pathways such Wnt , BMP, TGF and Ras/MAPK. In the present study, we observed that Dab2 is expressed in all the compartments of the hair follicle. K14 Cre specific homozygous Dab2 knockout resulted in delayed activation of HFSCs and delayed Ist hair follicle cycle initiation. At PD35, while WT progresses to anagen II, the Dab2 cKO mice still remains at telogen. In addition, loss of Dab2 alos led to reduced HFSCs pool extended quiescence, and reduced self renewal capacity of HFSCs at PD35. We performed expression profiling of HFSCs isolated from WT and Dab2 cKO mice at PD35 to check for the differentially regulated genes involved in HFSCs activation. The expression analysis helped us to elucidate the detailed molecular mechanisms involved in Dab2 mediated regulation of HFSCs activation and quiescence.
Project description:Disabled 2 is an endocytic adaptor protein known to regulate various signaling pathways such Wnt , BMP, TGF and Ras/MAPK. In the present study, we observed that Dab2 is expressed in all the compartments of the hair follicle. K14 Cre specific homozygous Dab2 knockout resulted in delayed activation of HFSCs and delayed Ist hair follicle cycle initiation. At PD68, both WT and Dab2 cKO mice were at telogen. In addition, loss of Dab2 also led to reduced HFSCs pool extended quiescence, and reduced self renewal capacity of HFSCs at PD68. We performed expression profiling of HFSCs isolated from WT and Dab2 cKO mice at PD68 to check for the differentially regulated genes involved in HFSCs activation. The expression analysis helped us to elucidate the detailed molecular mechanisms involved in Dab2 mediated regulation of HFSCs activation and quiescence.
Project description:In many organs, adult stem cells are uniquely poised to serve as cancer cells of origin. In the epidermis, hair follicle stem cells (HFSCs) cycle through stages of quiescence (telogen) and proliferation (anagen) to drive hair growth. Within the hair follicle, HFSCs are capable of initiating squamous cell carcinoma, yet it is unclear how the hair cycle contributes to tumorigenesis. The data presented here show that HFSCs are unable to initiate tumors during the quiescent phase of the hair cycle, indicating that the mechanisms that keep HFSCs dormant are dominant to gain of oncogenes (Ras) or loss of tumor suppressors (p53). Instead, prolonged oncogenic stimuli only exert their effects when HFSC quiescence mechanisms are removed by normal HFSC activation. Furthermore, Pten activity is necessary for quiescence based tumor suppression, since Pten deletion alleviates this stem cell specific ability without affecting proliferation per se. Small RNAs were cloned from Trizol-lysed cells sorted from mouse skin and sequenced with the Illumina HiSeq2000.
Project description:Quiescent stem cells are periodically activated to maintain tissue homeostasis or occasionally called into action upon injury. Molecular mechanisms that constitutively maintain stem cell identity or promote stem cell proliferation and differentiation upon activation have been extensively studied. However, it is unclear how quiescent stem cells maintain identity and reinforce quiescence when they transition from quiescence to activation. Here we show mouse hair follicle stem cell compartment induces a transcription factor, Foxc1, when activated. Importantly, deletion of Foxc1 in the activated but not quiescent stem cells compromises stem cell identity, fails to re-establish quiescence and subsequently drives premature stem cell activation.These findings uncover a dynamic, cell-intrinsic mechanism employed by hair follicle stem cells to reinforce stemness in response to activation. Poly(A)-enriched transcriptome RNA-seq on HFSCs isolated in WT and K14Cre cKO mice at anagen and early telogen stage of hair cycle.
Project description:In many organs, adult stem cells are uniquely poised to serve as cancer cells of origin. In the epidermis, hair follicle stem cells (HFSCs) cycle through stages of quiescence (telogen) and proliferation (anagen) to drive hair growth. Within the hair follicle, HFSCs are capable of initiating squamous cell carcinoma, yet it is unclear how the hair cycle contributes to tumorigenesis. The data presented here show that HFSCs are unable to initiate tumors during the quiescent phase of the hair cycle, indicating that the mechanisms that keep HFSCs dormant are dominant to gain of oncogenes (Ras) or loss of tumor suppressors (p53). Instead, prolonged oncogenic stimuli only exert their effects when HFSC quiescence mechanisms are removed by normal HFSC activation. Furthermore, Pten activity is necessary for quiescence based tumor suppression, since Pten deletion alleviates this stem cell specific ability without affecting proliferation per se.
Project description:Gene expression profile of hair follicle stem cells (HFSCs) isolated from wild type and homozygous Dab2 cKO (Dab2 Fl/Fl) mice at postnatal day 35
Project description:Gene expression profile of hair follicle stem cells (HFSCs) isolated from wild type and homozygous Dab2 cKO (Dab2 Fl/Fl) mice at postnatal day 68
Project description:Piloerection (goosebump) requires concerted actions of the hair follicle, the arrector pili muscle (APM), and the sympathetic nerve, providing a model to study interactions across epithelium, mesenchyme, and nerves. Here, we show that APMs and sympathetic nerves form a dual component niche to modulate hair follicle stem cell (HFSC) activity. Sympathetic nerves form synapse-like structures with HFSCs and regulate HFSCs through norepinephrine, whereas APMs maintain sympathetic innervation to HFSCs. Without norepinephrine signaling, HFSCs enter a deep quiescence state by down-regulating cell cycle machinery and mitochondria metabolism, while up-regulating quiescence regulators Lhx2, Foxp1, and Fgf18. During development, HFSC progeny secrets Sonic Hedgehog (SHH) to direct the formation of this APM-sympathetic nerve niche, which in turn controls hair follicle regeneration in adults. Our results reveal a reciprocal interdependence between a regenerative tissue and its niche at different stages, and illustrate that nerves can modulate stem cell quiescence through synapses and neurotransmitters.
Project description:In some organs, adult stem cells are uniquely poised to serve as cancer cells of origin1-4. It is unclear, however, whether tumorigenesis is influenced by the activation state of the adult stem cell. Hair follicle stem cells (HFSCs) act as cancer cells of origin for cutaneous squamous cell carcinoma (SCC) and undergo defined cycles of quiescence and activation. The data presented here show that HFSCs are unable to initiate tumors during the quiescent phase of the hair cycle, indicating that the mechanisms that keep HFSCs dormant are dominant to the gain of oncogenes (Ras) or the loss of tumor suppressors (p53). Furthermore, Pten activity is necessary for quiescence based tumor suppression, as its deletion alleviates tumor suppression without affecting proliferation. These data demonstrate that stem cell quiescence is a form of tumor suppression in HFSCs, and that Pten plays a role in maintaining quiescence in the presence of tumorigenic stimuli. This experiment includes RNA profiling of hair follicle stem cells at various stages of tumorigenesis
Project description:We report downstream gene expression changes in stem cells of the adult mouse hair follicle upon conditional ablating of the transcription factor Forkhead Box C1 transcription factor (FOXC1). Hair follicles undergo cycles of rest (telogen; Tel) and regeneration (anagen; Ana). As such, we performed our analysis on these two different stages of hair follicles. mRNA-sequencing of WT vs. Foxc1-conditional or inducible KO (Foxc1-cKO or iKO) hair follicle stem cells (HFSCs) purified from mouse dorsal back skin by flow-activated cell sorting (FACS).
Project description:In some organs, adult stem cells are uniquely poised to serve as cancer cells of origin1-4. It is unclear, however, whether tumorigenesis is influenced by the activation state of the adult stem cell. Hair follicle stem cells (HFSCs) act as cancer cells of origin for cutaneous squamous cell carcinoma (SCC) and undergo defined cycles of quiescence and activation. The data presented here show that HFSCs are unable to initiate tumors during the quiescent phase of the hair cycle, indicating that the mechanisms that keep HFSCs dormant are dominant to the gain of oncogenes (Ras) or the loss of tumor suppressors (p53). Furthermore, Pten activity is necessary for quiescence based tumor suppression, as its deletion alleviates tumor suppression without affecting proliferation. These data demonstrate that stem cell quiescence is a form of tumor suppression in HFSCs, and that Pten plays a role in maintaining quiescence in the presence of tumorigenic stimuli. This experiment includes RNA profiling of hair follicle stem cells at various stages of tumorigenesis Briefly: HFSCs were lineage traced with YFP allele, FACS isolated from various genotypes, and then profiled by Affymetrix microarray Cell Isolation and FACS: Whole dorsal and ventral mouse K15-CrePR; LSLYFP, K15-CrePR; KrasG12D; LSLYFP and K15-CrePR; KrasG12D; Ptenff; LSLYFP was extracted, diced and digested with collagenase (20mg/ml) for 2 hours at 37C, then an equal volume of .25% trypsin was added and digestion continued for an additional hour at 37C. Digested tissue was mechanically dispersed via pipette and filtered with a 100uM cell strainer, collected at 300g and washed twice with PBS. The cells were then filtered through a 40uM cell strainer and FACS processed. YFP+ and YFP- cell populations were collected in RNA lysis buffer (Stratagene) and stored at -80C. Gene expression profiling Microarray analyses by GeneSpring software were performed