The Experts below are selected from a list of 27 Experts worldwide ranked by ideXlab platform
Manabu Ohyama - One of the best experts on this subject based on the ideXlab platform.
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canine follicle stem Cell candidates reside in the Bulge and share characteristic features with human Bulge Cells
Journal of Investigative Dermatology, 2010Co-Authors: Toshiroh Iwasaki, Tetsuro Kobayashi, Masayuki Amagai, Manabu OhyamaAbstract:The hair follicle Bulge has attracted great interest as a stem Cell repository. Previous studies have focused on rodent or human Bulge stem Cells, and our understanding of those in other species is limited. In this study, we attempted to localize and characterize stem Cell candidates in canine hair follicles. The canine skin xenografting study located label-retaining Cells in the outer root sheath around the insertion point of the arrector pili muscle, where the immunoreactivity of human Bulge markers, keratin 15 and follistatin, were detected. Canine Bulge Cell-enriched keratinocytes up-regulated human Bulge biomarkers CD200 and DIO2, and conserved key Cell regulators of Bulge stem Cells, such as SOX9 and LHX2. Importantly, canine Bulge-derived keratinocytes were highly proliferative in vitro and, when combined with trichogenic dermal Cells, reconstituted pilosebaceous structures as well as the epidermis in vivo. Successful detection of canine specific DNA sequences suggested that the regenerated tissue was of canine origin. In addition, canine specific Bulge Cell and sebocyte lineage markers were expressed in reconstituted pilosebaceous units, implying the multipotency of canine Bulge Cells. Our findings demonstrate a unique strategy utilizing canine Bulge Cells to investigate human stem Cell biology and intractable hair disorders that involve the Bulge region.
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advances in the study of stem Cell enriched hair follicle Bulge Cells a review featuring characterization and isolation of human Bulge Cells
Dermatology, 2007Co-Authors: Manabu OhyamaAbstract:Hair follicles repeatedly regress and reconstitute themselves, suggesting the presence of intrinsic tissue stem Cells. Using label-retaining Cell technique to detect slow-cycling stem Cells, hair follicle stem Cells were detected in the Bulge region of the outer root sheath, which provides the insertion point for the arrector pili muscle and marks the bottom of the permanent portion of hair follicles. Later studies elucidated important stem Cell characteristics of the Bulge Cells, including high proliferative capacity and multipotency to regenerate the pilosebaceous unit as well as epidermis. Isolation of living Bulge Cells is now feasible. In addition, microarray analyses revealed the global gene expression profile of the Bulge Cells. However, most of those studies were performed in mouse hair follicles and our understanding of human Bulge Cells has been limited. Recently, remarkable progress was made in human Bulge Cell biology. The morphologically ill-defined human Bulge boundary was precisely determined by the distribution of label-retaining Cells. Laser capture microdissection enabled accurate isolation of human Bulge Cells and control Cell populations. Microarray comparison analyses between isolated Bulge and nonBulge Cells elucidated the molecular signature of human Bulge Cells and identified Cell surface markers for living Bulge Cell isolation. Importantly, isolated living human Bulge Cells demonstrated stem Cell characteristics in vitro. In this review, recent advances in hair follicle Bulge Cell research are summarized, especially focusing on the characterization and isolation of human Bulge Cells.
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characterization and isolation of stem Cell enriched human hair follicle Bulge Cells
Journal of Clinical Investigation, 2005Co-Authors: Manabu Ohyama, Atsushi Terunuma, Christine L Tock, Michael F Radonovich, Cynthia A Pisemasison, Steven B Hopping, John N Brady, Mark C Udey, Jonathan C VogelAbstract:The human hair follicle Bulge is an important niche for keratinocyte stem Cells (KSCs). Elucidation of human Bulge Cell biology could be facilitated by analysis of global gene expression profiles and identification of unique Cell-surface markers. The lack of distinctive Bulge morphology in human hair follicles has hampered studies of Bulge Cells and KSCs. In this study, we determined the distribution of label-retaining Cells to define the human anagen Bulge. Using navigated laser capture microdissection, Bulge Cells and outer root sheath Cells from other follicle regions were obtained and analyzed with cDNA microarrays. Gene transcripts encoding inhibitors of WNT and activin/bone morphogenic protein signaling were overrepresented in the Bulge, while genes responsible for Cell proliferation were underrepresented, consistent with the existence of quiescent noncycling KSCs in anagen follicles. Positive markers for Bulge Cells included CD200, PHLDA1, follistatin, and frizzled homolog 1, while CD24, CD34, CD71, and CD146 were preferentially expressed by non-Bulge keratinocytes. Importantly, CD200+ Cells (CD200hiCD24loCD34loCD71loCD146lo) obtained from hair follicle suspensions demonstrated high colony-forming efficiency in clonogenic assays, indicating successful enrichment of living human Bulge stem Cells. The stem Cell behavior of enriched Bulge Cells and their utility for gene therapy and hair regeneration will need to be assessed in in vivo assays.
George Cotsarelis - One of the best experts on this subject based on the ideXlab platform.
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epithelial stem Cells a folliculocentric view
Journal of Investigative Dermatology, 2006Co-Authors: George CotsarelisAbstract:Putative epithelial stem Cells were identified in the hair follicle Bulge as quiescent "label retaining Cells". The study of these Cells was hindered until the identification of Bulge Cell molecular markers, such as CD34 expression and K15 promoter activity. This allowed for the isolation and characterization of Bulge Cells from mouse follicles. Bulge Cells possess stem Cell characteristics, including multipotency, high proliferative potential, and their cardinal feature of quiescence. Lineage analysis demonstrated that all epithelial layers within the adult follicle and hair originated from Bulge Cells. Bulge Cells only contribute to the epidermis during wound healing, but after isolation, when combined with neonatal dermal Cells, they regenerate new hair follicles, epidermis, and sebaceous glands. Bulge Cells maintain their stem Cell characteristics after propagation in vitro, thus ultimately they may be useful for tissue engineering applications. Understanding the signals important for directing movement and differentiation of Bulge Cells into different lineages will be important for developing treatments based on stem Cells as well as clarifying their role in skin disease.
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hair follicle stem Cells in the lower Bulge form the secondary germ a biochemically distinct but functionally equivalent progenitor Cell population at the termination of catagen
Differentiation, 2004Co-Authors: Kenji Kizawa, Kazuto Hamada, George CotsarelisAbstract:The lowermost portion of the resting (telogen) follicle consists of the Bulge and secondary hair germ. We previously showed that the progeny of stem Cells in the Bulge form the lower follicle and hair, but the relationship of the Bulge Cells with the secondary hair germ Cells, which are also involved in the generation of the new hair at the onset of the hair growth cycle (anagen), remains unclear. Here we address whether secondary hair germ Cells are derived directly from epithelial stem Cells in the adjacent Bulge or whether they arise from Cells within the lower follicle that survive the degenerative phase of the hair cycle (catagen). We use 5-bromo-2′-deoxyuridine to label Bulge Cells at anagen onset, and demonstrate that the lowermost portion of the Bulge collapses around the hair and forms the secondary hair germ during late catagen. During the first six days of anagen onset Bulge Cells proliferate and self-renew. Bulge Cell proliferation at this time also generates Cells that form the future secondary germ. As Bulge Cells form the secondary germ Cells at the end of catagen, they lose expression of a biochemical marker, S100A6. Remarkably, however, following injury of Bulge Cells by hair depilation, progenitor Cells in the secondary hair germ repopulate the Bulge and re-express Bulge Cell markers. These findings support the notion that keratinocytes can “dedifferentiate” to a stem Cell state in response to wounding, perhaps related to signals from the stem Cell niche. Finally, we also present evidence that quiescent Bulge Cells undergo apoptosis during follicle remodeling in catagen, indicating that a subpopulation of Bulge Cells is not permanent.
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enrichment for living murine keratinocytes from the hair follicle Bulge with the Cell surface marker cd34
Journal of Investigative Dermatology, 2003Co-Authors: Carol S Trempus, George Cotsarelis, Rebecca J Morris, Carl D Bortner, Randall S Faircloth, Jeffrey M Reece, Raymond W TennantAbstract:It is widely believed that epithelial stem Cells reside in the hair follicle Bulge region. We investigated the hematopoietic stem and progenitor Cell marker, CD34, as a potential marker of hair follicle Bulge keratinocytes. Using a CD34-specific antibody, we identified intense membrane staining on keratinocytes in the Bulge region of the mouse hair follicle. CD34 expression colocalized with both slowly cycling (label retaining) Cells and keratin 15 expression. Live CD34 + keratinocytes were positively selected using antibodies to CD34 and α6 integrin in combination with fluorescent activated Cell sorting. Sorted Cells were analyzed for DNA content, and a staining profile was generated to confirm these Cells as keratinocytes. CD34 + keratinocytes were predominantly in G o /G 1 , in contrast to CD34 – Cells, which had well defined G 2 /M and S phases. In addition, CD34 + keratinocytes were found to express α6 integrin more intensely than CD34 – Cells (p + keratinocytes formed larger colonies than CD34 – Cells (p 0.05), indicating a higher proliferative potential. All flow-sorted Cells were positive for keratin 14 expression, and negative for keratin 1, loricrin, vimentin, and CD31. The majority of CD34 + Cells (98%) were positive for keratin 6, establishing this population as basal keratinocytes of follicular origin. CD34 message was detected by reverse transcription polymerase chain reaction predominantly in the CD34 + keratinocytes, confirming specificity of the antibody. This work is the first to demonstrate that CD34 is a specific marker of Bulge Cell keratinocytes in the cutaneous epithelium. Furthermore, the use of this marker facilitates isolation of live epithelial Cells with stem and progenitor Cell characteristics, potentially providing a tool for the study of carcinogen target Cells, gene therapy, and tissue engineering applications.
Tetsuro Kobayashi - One of the best experts on this subject based on the ideXlab platform.
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canine follicle stem Cell candidates reside in the Bulge and share characteristic features with human Bulge Cells
Journal of Investigative Dermatology, 2010Co-Authors: Toshiroh Iwasaki, Tetsuro Kobayashi, Masayuki Amagai, Manabu OhyamaAbstract:The hair follicle Bulge has attracted great interest as a stem Cell repository. Previous studies have focused on rodent or human Bulge stem Cells, and our understanding of those in other species is limited. In this study, we attempted to localize and characterize stem Cell candidates in canine hair follicles. The canine skin xenografting study located label-retaining Cells in the outer root sheath around the insertion point of the arrector pili muscle, where the immunoreactivity of human Bulge markers, keratin 15 and follistatin, were detected. Canine Bulge Cell-enriched keratinocytes up-regulated human Bulge biomarkers CD200 and DIO2, and conserved key Cell regulators of Bulge stem Cells, such as SOX9 and LHX2. Importantly, canine Bulge-derived keratinocytes were highly proliferative in vitro and, when combined with trichogenic dermal Cells, reconstituted pilosebaceous structures as well as the epidermis in vivo. Successful detection of canine specific DNA sequences suggested that the regenerated tissue was of canine origin. In addition, canine specific Bulge Cell and sebocyte lineage markers were expressed in reconstituted pilosebaceous units, implying the multipotency of canine Bulge Cells. Our findings demonstrate a unique strategy utilizing canine Bulge Cells to investigate human stem Cell biology and intractable hair disorders that involve the Bulge region.
Gary J Fisher - One of the best experts on this subject based on the ideXlab platform.
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hedgehog signaling maintains hair follicle stem Cell phenotype in young and aged human skin
Aging Cell, 2009Co-Authors: Laure Rittie, Stefan W Stoll, Sewon Kang, John J Voorhees, Gary J FisherAbstract:Skin hair follicles (HF) contain Bulge stem Cells (SC) that regenerate HFs during hair cycles, and repair skin epithelia following injury. As natural aging is associated with decreased skin repair capacity in humans, we have investigated the impact of age on human scalp HF Bulge Cell number and function. Here, we isolated human Bulge Cells, characterized as CD200+/KRT15+/KRT19+ Cells of the HF, by dissection-combined CD200 selection in young and aged human skin. Targeted transcriptional profiling indicates that KRT15, KRT19, Dkk3, Dkk4, Tcf3, S100A4, Gas1, EGFR and CTGF/CCN2 are also preferentially expressed by human Bulge Cells, compared to differentiated HF keratinocytes (KC). Our results demonstrate that aging does not alter expression or localization of these HF SC markers. In addition, we could not detect significant differences in HF density or Bulge Cell number between young and aged human scalp skin. Interestingly, hedgehog (Hh) signaling is activated in human Bulge Cells in vivo, and down-regulated in differentiated HF KCs, both in young and aged skin. In addition, activation of Hh signaling by lentivirus-mediated overexpression of transcription factor Gli1 induces transcription of HF SC markers KRT15, KRT19, and Gas1, in cultured KCs. Together with previously reported knock-out mouse results, these data suggest a role for Hh signaling in maintaining Bulge Cell phenotype in young and aged human skin.
Masayuki Amagai - One of the best experts on this subject based on the ideXlab platform.
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canine follicle stem Cell candidates reside in the Bulge and share characteristic features with human Bulge Cells
Journal of Investigative Dermatology, 2010Co-Authors: Toshiroh Iwasaki, Tetsuro Kobayashi, Masayuki Amagai, Manabu OhyamaAbstract:The hair follicle Bulge has attracted great interest as a stem Cell repository. Previous studies have focused on rodent or human Bulge stem Cells, and our understanding of those in other species is limited. In this study, we attempted to localize and characterize stem Cell candidates in canine hair follicles. The canine skin xenografting study located label-retaining Cells in the outer root sheath around the insertion point of the arrector pili muscle, where the immunoreactivity of human Bulge markers, keratin 15 and follistatin, were detected. Canine Bulge Cell-enriched keratinocytes up-regulated human Bulge biomarkers CD200 and DIO2, and conserved key Cell regulators of Bulge stem Cells, such as SOX9 and LHX2. Importantly, canine Bulge-derived keratinocytes were highly proliferative in vitro and, when combined with trichogenic dermal Cells, reconstituted pilosebaceous structures as well as the epidermis in vivo. Successful detection of canine specific DNA sequences suggested that the regenerated tissue was of canine origin. In addition, canine specific Bulge Cell and sebocyte lineage markers were expressed in reconstituted pilosebaceous units, implying the multipotency of canine Bulge Cells. Our findings demonstrate a unique strategy utilizing canine Bulge Cells to investigate human stem Cell biology and intractable hair disorders that involve the Bulge region.
