Skin melanocytes: biology and development

PubMed Central

Wachulska, Małgorzata; Stasiewicz, Aneta; Tymińska, Agata

2013-01-01

In the human skin, melanocytes are present in the epidermis and hair follicles. The basic features of these cells are the ability to melanin production and the origin from neural crest cells. This last element is important because there are other cells able to produce melanin but of different embryonic origin (pigmented epithelium of retina, some neurons, adipocytes). The life cycle of melanocyte consists of several steps including differentiation of melanocyte lineage/s from neural crest, migration and proliferation of melanoblasts, differentiation of melanoblasts into melanocytes, proliferation and maturation of melanocytes at the target places (activity of melanogenic enzymes, melanosome formation and transport to keratinocytes) and eventual cell death (hair melanocytes). Melanocytes of the epidermis and hair are cells sharing some common features but in general they form biologically different populations living in unique niches of the skin. PMID:24278043

[Effect of Tribulus terrestris extract on melanocyte-stimulating hormone expression in mouse hair follicles].

PubMed

Yang, Liu; Lu, Jian-wei; An, Jing; Jiang, Xuan

2006-12-01

To observe the effect of Tribulus terrestris extract on melanocyte stimulating hormone (MSH) expression in C57BL/6J mouse hair follicles, and investigate the role of Tribulus terrestris extract in activation, proliferation, epidermal migration of dormant hair follicle melanocytes. The aqueous extract of Tribulus terrestris was administered orally in specific pathogen-free C57BL/6J mouse at the daily dose equivalent to 1 g/1 kg in adult human, and the expression and distribution of MSH in the mouse hair follicles was observed with immunohistochemistry. The positivity rate of MSH expression in the hair follicle melanocytes was 75% in mice treated with the extract, significantly higher than the rate of only 18.75% in the control group (P<0.01). The aqueous extract of Tribulus terrestris can significantly increase MSH expression in the hair follicle melanocytes by activating tyrosinase activity and promoting melanocyte proliferation, melanine synthesis, and epidermal migration of dormant melanocytes.

Giant congenital melanocytic nevus*

PubMed Central

Viana, Ana Carolina Leite; Gontijo, Bernardo; Bittencourt, Flávia Vasques

2013-01-01

Giant congenital melanocytic nevus is usually defined as a melanocytic lesion present at birth that will reach a diameter ≥ 20 cm in adulthood. Its incidence is estimated in <1:20,000 newborns. Despite its rarity, this lesion is important because it may associate with severe complications such as malignant melanoma, affect the central nervous system (neurocutaneous melanosis), and have major psychosocial impact on the patient and his family due to its unsightly appearance. Giant congenital melanocytic nevus generally presents as a brown lesion, with flat or mammilated surface, well-demarcated borders and hypertrichosis. Congenital melanocytic nevus is primarily a clinical diagnosis. However, congenital nevi are histologically distinguished from acquired nevi mainly by their larger size, the spread of the nevus cells to the deep layers of the skin and by their more varied architecture and morphology. Although giant congenital melanocytic nevus is recognized as a risk factor for the development of melanoma, the precise magnitude of this risk is still controversial. The estimated lifetime risk of developing melanoma varies from 5 to 10%. On account of these uncertainties and the size of the lesions, the management of giant congenital melanocytic nevus needs individualization. Treatment may include surgical and non-surgical procedures, psychological intervention and/or clinical follow-up, with special attention to changes in color, texture or on the surface of the lesion. The only absolute indication for surgery in giant congenital melanocytic nevus is the development of a malignant neoplasm on the lesion. PMID:24474093

Identification of progenitor cancer stem cell in lentigo maligna melanoma.

PubMed

Bongiorno, M R; Doukaki, S; Malleo, F; Aricò, M

2008-07-01

The potential role of stem cells in neoplasia has aroused considerable interest over the past few years. A number of known biologic characteristics of melanomas support the theory that they may originate in a mutated stem cell. Melanocytic stem cell markers have been described recently. Moreover, the CD133 cells that show surface markers for CD34 are stem cells primitive. These stem cells are capable of differentiating into neurons, glia, keratinocytes, smooth muscle cells, and melanocytes in vitro. The identification of cancer stem/initiating cells with a crucial role in tumor formation may open up new pharmacologic perspectives. The purpose of this study is to detect the expression of CD133 and CD34, two putative markers of cancer stem cells in the lentigo maligna melanoma. Thirty cases of lentigo maligna melanoma were analyzed using indirect immunohistochemical staining. The vast majority of the samples analyzed showed the presence of rare cells, which were clearly positive for CD133 and CD34. Strong CD133 and CD34 staining was found in the outer root sheath of the mid-lower hair follicles, intermixed with atypical melanocytes extending along layers of the hair follicles. A number of these staminal cells were adjacent and intermixed with melanoma cells. This study supports the stem cell origin of this tumor and suggests that the precursor of the melanoma in question is a stem-like cell rather than the primitive melanoblast committed to be exclusively involved in melanocytic differentiation.

Clinical grade adult stem cell banking

PubMed Central

Thirumala, Sreedhar; Goebel, W Scott

2009-01-01

There has been a great deal of scientific interest recently generated by the potential therapeutic applications of adult stem cells in human care but there are several challenges regarding quality and safety in clinical applications and a number of these challenges relate to the processing and banking of these cells ex-vivo. As the number of clinical trials and the variety of adult cells used in regenerative therapy increases, safety remains a primary concern. This has inspired many nations to formulate guidelines and standards for the quality of stem cell collection, processing, testing, banking, packaging and distribution. Clinically applicable cryopreservation and banking of adult stem cells offers unique opportunities to advance the potential uses and widespread implementation of these cells in clinical applications. Most current cryopreservation protocols include animal serum proteins and potentially toxic cryoprotectant additives (CPAs) that prevent direct use of these cells in human therapeutic applications. Long term cryopreservation of adult stem cells under good manufacturing conditions using animal product free solutions is critical to the widespread clinical implementation of ex-vivo adult stem cell therapies. Furthermore, to avoid any potential cryoprotectant related complications, reduced CPA concentrations and efficient post-thaw washing to remove CPA are also desirable. The present review focuses on the current strategies and important aspects of adult stem cell banking for clinical applications. These include current good manufacturing practices (cGMPs), animal protein free freezing solutions, cryoprotectants, freezing & thawing protocols, viability assays, packaging and distribution. The importance and benefits of banking clinical grade adult stem cells are also discussed. PMID:20046678

Pirin Inhibits Cellular Senescence in Melanocytic Cells

PubMed Central

Licciulli, Silvia; Luise, Chiara; Scafetta, Gaia; Capra, Maria; Giardina, Giuseppina; Nuciforo, Paolo; Bosari, Silvano; Viale, Giuseppe; Mazzarol, Giovanni; Tonelli, Chiara; Lanfrancone, Luisa; Alcalay, Myriam

2011-01-01

Cellular senescence has been widely recognized as a tumor suppressing mechanism that acts as a barrier to cancer development after oncogenic stimuli. A prominent in vivo model of the senescence barrier is represented by nevi, which are composed of melanocytes that, after an initial phase of proliferation induced by activated oncogenes (most commonly BRAF), are blocked in a state of cellular senescence. Transformation to melanoma occurs when genes involved in controlling senescence are mutated or silenced and cells reacquire the capacity to proliferate. Pirin (PIR) is a highly conserved nuclear protein that likely functions as a transcriptional regulator whose expression levels are altered in different types of tumors. We analyzed the expression pattern of PIR in adult human tissues and found that it is expressed in melanocytes and has a complex pattern of regulation in nevi and melanoma: it is rarely detected in mature nevi, but is expressed at high levels in a subset of melanomas. Loss of function and overexpression experiments in normal and transformed melanocytic cells revealed that PIR is involved in the negative control of cellular senescence and that its expression is necessary to overcome the senescence barrier. Our results suggest that PIR may have a relevant role in melanoma progression. PMID:21514450

Adult Stem Cells and Diseases of Aging

PubMed Central

Boyette, Lisa B.; Tuan, Rocky S.

2014-01-01

Preservation of adult stem cells pools is critical for maintaining tissue homeostasis into old age. Exhaustion of adult stem cell pools as a result of deranged metabolic signaling, premature senescence as a response to oncogenic insults to the somatic genome, and other causes contribute to tissue degeneration with age. Both progeria, an extreme example of early-onset aging, and heritable longevity have provided avenues to study regulation of the aging program and its impact on adult stem cell compartments. In this review, we discuss recent findings concerning the effects of aging on stem cells, contributions of stem cells to age-related pathologies, examples of signaling pathways at work in these processes, and lessons about cellular aging gleaned from the development and refinement of cellular reprogramming technologies. We highlight emerging therapeutic approaches to manipulation of key signaling pathways corrupting or exhausting adult stem cells, as well as other approaches targeted at maintaining robust stem cell pools to extend not only lifespan but healthspan. PMID:24757526

Childhood malignant blue nevus of the ear associated with two intracranial melanocytic tumors-metastases or neurocutaneous melanosis?

PubMed

Popović, Mara; Dolenc-Strazar, Zvezdana; Anzic, Jozica; Luzar, Bostjan

2004-10-01

Blue nevus is an uncommon pigmented tumor of dermal melanocytes that has traditionally been classified into common and cellular variant. It is usually a skin tumor in adults but can become apparent in early childhood or even be present at birth. Malignant blue nevus is a rare melanocytic tumor of the skin arising from a preexisting cellular blue nevus. We report a multinodular blue nevus of the left ear in an 11-year-old girl who also had 2 intracranial melanocytic lesions. Differential diagnosis between metastases from malignant blue nevus and neurocutaneous melanosis is discussed.

Elements of the niche for adult stem cell expansion

PubMed Central

Redondo, Patricia A; Pavlou, Marina; Loizidou, Marilena; Cheema, Umber

2017-01-01

Adult stem cells are crucial for tissue homeostasis. These cells reside within exclusive locations in tissues, termed niches, which protect adult stem cell fidelity and regulate their many functions through biophysical-, biochemical- and cellular-mediated mechanisms. There is a growing understanding of how these mechanisms and their components contribute towards maintaining stem cell quiescence, self-renewal, expansion and differentiation patterns. In vitro expansion of adult stem cells is a powerful tool for understanding stem cell biology, and for tissue engineering and regenerative medicine applications. However, it is technically challenging, since adult stem cell removal from their native microenvironment has negative repercussions on their sustainability. In this review, we overview specific elements of the biomimetic niche and how recreating such elements can help in vitro propagation of adult stem cells. PMID:28890779

Elements of the niche for adult stem cell expansion.

PubMed

Redondo, Patricia A; Pavlou, Marina; Loizidou, Marilena; Cheema, Umber

2017-01-01

Adult stem cells are crucial for tissue homeostasis. These cells reside within exclusive locations in tissues, termed niches, which protect adult stem cell fidelity and regulate their many functions through biophysical-, biochemical- and cellular-mediated mechanisms. There is a growing understanding of how these mechanisms and their components contribute towards maintaining stem cell quiescence, self-renewal, expansion and differentiation patterns. In vitro expansion of adult stem cells is a powerful tool for understanding stem cell biology, and for tissue engineering and regenerative medicine applications. However, it is technically challenging, since adult stem cell removal from their native microenvironment has negative repercussions on their sustainability. In this review, we overview specific elements of the biomimetic niche and how recreating such elements can help in vitro propagation of adult stem cells.

A light-colored region of caudal fin: a niche of melanocyte progenitors in crucian carp (Cyprinus carpio L.).

PubMed

Huang, Yaping; Luo, Yurong; Liu, Jinhui; Gui, Saiyu; Wang, Mei; Liu, Wenbin; Peng, Liangyue; Xiao, Yamei

2017-01-01

Melanocyte stem cells are a population of immature cells which sustain the self-renewal and replenish the differentiated melanocytes. In this research, a light-colored region (LCR) is observed at the heel of caudal fin in juvenile crucian carp. By cutting off the caudal fin, the operated caudal fin can regenerate in accordance with the original pigment pattern from the retained LCR. As markers of stem cells, Oct4 and Sox2 have been found to be highly expressed in the LCR as well as Mitfa, a label of the melanoblasts. In vitro, Mitfa + melanoblasts are observed in the cells which are derived from the LCR and transfected with Mitfa-EGFP reporter by using Tol2 transposon system. Furthermore, by real-time qPCR, it is shown that the level of sox2 mRNA is gradually decreased from the LCR to proximal and distal caudal fin, and that of mitfa mRNA in the proximal caudal fin (PCF) is higher than that in the LCR, while it is the lowest in the distal caudal fin. Hence, we propose that the LCR is a pigment progenitor niche, sending melanocytes to the distal of caudal fin, which gradually emerges as caudal fin grow. We reveal that the LCR of caudal fin might be a niche of pigment progenitors, and contribute to pigment-producing stem cells in crucian carp. © 2016 International Federation for Cell Biology.

Adult Stem Cell Therapy for Stroke: Challenges and Progress

PubMed Central

Bang, Oh Young; Kim, Eun Hee; Cha, Jae Min; Moon, Gyeong Joon

2016-01-01

Stroke is one of the leading causes of death and physical disability among adults. It has been 15 years since clinical trials of stem cell therapy in patients with stroke have been conducted using adult stem cells like mesenchymal stem cells and bone marrow mononuclear cells. Results of randomized controlled trials showed that adult stem cell therapy was safe but its efficacy was modest, underscoring the need for new stem cell therapy strategies. The primary limitations of current stem cell therapies include (a) the limited source of engraftable stem cells, (b) the presence of optimal time window for stem cell therapies, (c) inherited limitation of stem cells in terms of growth, trophic support, and differentiation potential, and (d) possible transplanted cell-mediated adverse effects, such as tumor formation. Here, we discuss recent advances that overcome these hurdles in adult stem cell therapy for stroke. PMID:27733032

Commentary: "re-programming or selecting adult stem cells?".

PubMed

Trosko, James E

2008-01-01

The recent observations that embryonic stemness-associated genes could assist in the "de-differentiation" of adult skin fibroblast cells to "embryonic-like stem cells", using the "somatic cell nuclear transfer" techniques, have been interpreted as indicating a "re-programming" of genes. These reports have demonstrated a "proof of principle" approach to by-pass many, but not all, of the ethical, scientific and medical limitations of the "therapeutic cloning" of embryonic stem cells from embryos. However, while the interpretation that real "re-programming" of all those somatic fibroblastic differentiation genes might be correct, there does exists an alternative hypothesis of these exciting results. Based on the fact that multipotent adult stem cells exist in most, if not all, adult organs, the possibility exists that all these recent "re-programming" results, using the somatic nuclear transfer techniques, actually were the results of transferred rare nuclear material from the adult stem cells residing in the skin of the mouse, monkey and human samples. An examination of the rationale for this challenging hypothesis has been drawn from the hypothesis of the "stem cell theory of cancer", as well as from the field of human adult stem cells research.

In search of adult renal stem cells.

PubMed

Anglani, F; Forino, M; Del Prete, D; Tosetto, E; Torregrossa, R; D'Angelo, A

2004-01-01

The therapeutic potential of adult stem cells in the treatment of chronic degenerative diseases has becoming increasingly evident over the last few years. Significant attention is currently being paid to the development of novel treatments for acute and chronic kidney diseases too. To date, promising sources of stem cells for renal therapies include adult bone marrow stem cells and the kidney precursors present in the early embryo. Both cells have clearly demonstrated their ability to differentiate into the kidney's specialized structures. Adult renal stem cells have yet to be identified, but the papilla is where the stem cell niche is probably located. Now we need to isolate and characterize the fraction of papillary cells that constitute the putative renal stem cells. Our growing understanding of the cellular and molecular mechanisms behind kidney regeneration and repair processes - together with a knowledge of the embryonic origin of renal cells - should induce us, however, to bear in mind that in the kidney, as in other mesenchymal tissues, the need for a real stem cell compartment might be less important than the phenotypic flexibility of tubular cells. Thus, by displaying their plasticity during kidney maintenance and repair, terminally differentiated cells may well function as multipotent stem cells despite being at a later stage of maturation than adult stem cells. One of the major tasks of Regenerative Medicine will be to disclose the molecular mechanisms underlying renal tubular plasticity and to exploit its biological and therapeutic potential.

Physiological characterization of ocular melanosis-affected canine melanocytes.

PubMed

Dawson-Baglien, Ethan M; Noland, Erica L; Sledge, Dodd G; Kiupel, Matti; Petersen-Jones, Simon M

2018-04-27

Cairn terriers with ocular melanosis (OM) accumulate large, heavily pigmented melanocytes in the anterior uvea. Darkly pigmented plaques develop within the sclera, leading us to hypothesize that OM uveal melanocytes may have an abnormal migratory capacity. Globes from OM-affected Cairn terriers and unaffected control eyes enucleated for reasons unrelated to this study were used for immunohistochemistry and to culture melanocytes for in vitro cell behavior assays. The scleral plaques of six dogs were immunolabeled for HMB-45, MelanA, PNL2, CD18, CD204, and Iba-1 and compared with the pigment cells accumulated within the irides. Cultured uveal melanocytes from OM-affected and control dogs were compared using conventional assays measuring cell proliferation, invasion capability, and melanin production. Melanocytes isolated from OM eyes had significantly elevated levels of per-cell melanin content and production compared to controls. The majority of pigmented cells in the scleral plaques were HMB45 positive indicating a melanocytic origin. Many were also CD18 positive. No differences were observed between cultured melanocytes from OM-affected and control uvea for standard in vitro proliferation or invasion assays. Pigmented cells which accumulate in the sclera of OM-affected Cairn terriers are predominantly melanocytes; however, in vitro assays of uveal melanocytes did not reveal differences in migratory behavior between OM and control cells. Migratory behavior of OM-melanocytes may be environment-dependent. We suggest that RNA sequencing and differential expression analysis would be a useful next step in understanding this disease. © 2018 American College of Veterinary Ophthalmologists.

Prostaglandin production by melanocytic cells and the effect of alpha-melanocyte stimulating hormone.

PubMed

Nicolaou, Anna; Estdale, Sian E; Tsatmali, Marina; Herrero, Daniel Pascual; Thody, Anthony J

2004-07-16

Prostaglandins are potent mediators of the inflammatory response and are also involved in cancer development. In this study, we show that human melanocytes and FM55 melanoma cells express cyclooxygenase-1 and -2 (COX-1 and -2) and thus have the capability to produce prostaglandins. The FM55 cells produced predominantly PGE2 and PGF2alpha, whereas the HaCaT keratinocyte cell line produced mainly PGE2. The anti-inflammatory peptide, alpha-melanocyte stimulating hormone (alpha-MSH), reduced prostaglandin production in FM55 and HaCaT cells and reversed the effect of the pro-inflammatory cytokine TNF-alpha in the former. These results indicate that melanocytes produce prostaglandins and that alpha-MSH, by inhibiting this response, may play an important role in regulating inflammatory responses in the skin.

Automatic evaluation of skin histopathological images for melanocytic features

NASA Astrophysics Data System (ADS)

Koosha, Mohaddeseh; Hoseini Alinodehi, S. Pourya; Nicolescu, Mircea; Safaei Naraghi, Zahra

2017-03-01

Successfully detecting melanocyte cells in the skin epidermis has great significance in skin histopathology. Because of the existence of cells with similar appearance to melanocytes in hematoxylin and eosin (HE) images of the epidermis, detecting melanocytes becomes a challenging task. This paper proposes a novel technique for the detection of melanocytes in HE images of the epidermis, based on the melanocyte color features, in the HSI color domain. Initially, an effective soft morphological filter is applied to the HE images in the HSI color domain to remove noise. Then a novel threshold-based technique is applied to distinguish the candidate melanocytes' nuclei. Similarly, the method is applied to find the candidate surrounding halos of the melanocytes. The candidate nuclei are associated with their surrounding halos using the suggested logical and statistical inferences. Finally, a fuzzy inference system is proposed, based on the HSI color information of a typical melanocyte in the epidermis, to calculate the similarity ratio of each candidate cell to a melanocyte. As our review on the literature shows, this is the first method evaluating epidermis cells for melanocyte similarity ratio. Experimental results on various images with different zooming factors show that the proposed method improves the results of previous works.

Melanocytic nevi and melanoma: unraveling a complex relationship

PubMed Central

Damsky, WE; Bosenberg, M

2018-01-01

Approximately 33% of melanomas are derived directly from benign, melanocytic nevi. Despite this, the vast majority of melanocytic nevi, which typically form as a result of BRAFV600E-activating mutations, will never progress to melanoma. Herein, we synthesize basic scientific insights and data from mouse models with common observations from clinical practice to comprehensively review melanocytic nevus biology. In particular, we focus on the mechanisms by which growth arrest is established after BRAFV600E mutation. Means by which growth arrest can be overcome and how melanocytic nevi relate to melanoma are also considered. Finally, we present a new conceptual paradigm for understanding the growth arrest of melanocytic nevi in vivo termed stable clonal expansion. This review builds upon the canonical hypothesis of oncogene-induced senescence in growth arrest and tumor suppression in melanocytic nevi and melanoma. PMID:28604751

The ultrastructure of conjunctival melanocytic tumors.

PubMed Central

Jakobiec, F A

1984-01-01

The ultrastructure of conjunctival melanocytic lesions in 49 patients was evaluated to find significant differences between benign and malignant cells. The patients studied included 9 with benign epithelial (racial) melanosis, 2 with pigmented squamous cell papillomas, 16 with conjunctival nevi, 18 with primary acquired melanosis, and 11 with invasive nodules of malignant melanoma. In benign epithelial melanosis, dendritic melanocytes were situated along the basement membrane region of the conjunctival epithelium, with one basilar dendritic melanocyte lodged among every five or six basilar keratinocytes. The dendritic melanocytes extended arborizing cellular processes between the basilar and among the suprabasilar keratinocytes, which manifested considerable uptake of melanin granules into their cytoplasm. The benign dendritic melanocytes possessed nuclei with clumped heterochromatin at the nuclear membrane, small, tightly wound nucleoli, and large, elongated, fully melaninized melanin granules. In two patients with benign hyperplasia of the dendritic melanocytes, occasional dendritic melanocytes were located in a suprabasilar position, but were always separated from each other by keratinocytes or their processes. In the two black patients with benign pigmented squamous papillomas, the benign dendritic melanocytes were located hapharzardly at all levels of the acanthotic epithelium and not just along the basement membrane region. Melanin uptake by the proliferating keratinocytes was minimal. In benign melanocytic nevi of the conjunctiva, nevus cells within the intraepithelial junctional nests displayed a more rounded cellular configuration; short villi and broader cellular processes suggestive of abortive dendrites were found. The nuclear chromatin pattern was clumped at the nuclear membrane, but the nucleoli were somewhat larger than those of benign dendritic melanocytes in epithelial melanosis. The melanosomes were smaller and rounder than those in dendritic

The usefulness of c-Kit in the immunohistochemical assessment of melanocytic lesions

PubMed Central

Pilloni, L.; Bianco, P.; Difelice, E.; Cabras, S.; Castellanos, M.E.; Atzori, L.; Ferreli, C.; Mulas, P.; Nemolato, S.; Faa, G.

2011-01-01

C-Kit (CD117), the receptor for the stem cell factor, a growth factor for melanocyte migration and proliferation, has shown differential immunostaining in various benign and malignant melanocytic lesions. The purpose of this study is to compare c-Kit immunostaining in benign nevi and in primary and metastatic malignant melanomas, to determine whether c-Kit can aid in the differential diagnosis of these lesions. c-Kit immunostaining was performed in 60 cases of pigmented lesions, including 39 benign nevi (5 blue nevi, 5 intra-dermal nevi, 3 junctional nevi, 15 cases of primary compound nevus, 11 cases of Spitz nevus), 18 cases of primary malignant melanoma and 3 cases of metastatic melanoma. The vast majority of nevi and melanomas examined in this study were positive for c-Kit, with minimal differences between benign and malignant lesions. C-Kit cytoplasmatic immunoreactivity in the intraepidermal proliferating nevus cells, was detected in benign pigmented lesions as well as in malignant melanoma, increasing with the age of patients (P=0.007) in both groups. The patient’s age at presentation appeared to be the variable able to cluster benign and malignant pigmented lesions. The percentage of c-Kit positive intraepidermal nevus cells was better associated with age despite other variables (P=0.014). The intensity and percentage of c-Kit positivity in the proliferating nevus cells in the dermis was significantly increased in malignant melanocytic lesions (P=0.015 and P=0.008) compared to benign lesions (compound melanocytic nevi, Spitz nevi, intradermal nevi, blue nevi). Immunostaning for c-Kit in metastatic melanomas was negative. Interestingly in two cases of melanoma occurring on a pre-existent nevus, the melanoma tumor cells showed strong cytoplasmatic and membranous positivity for c-kit, in contrast with the absence of any immunoreactivity in pre-existent intradermal nevus cells. C-Kit does not appear to be a strong immunohistochemical marker for distinguishing

Intestinal stem cells in the adult Drosophila midgut

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Huaqi, E-mail: Huaqi.Jiang@UTSouthwestern.edu; Edgar, Bruce A., E-mail: b.edgar@dkfz.de; Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N., Seattle, WA 98109

Drosophila has long been an excellent model organism for studying stem cell biology. Notably, studies of Drosophila's germline stem cells have been instrumental in developing the stem cell niche concept. The recent discovery of somatic stem cells in adult Drosophila, particularly the intestinal stem cells (ISCs) of the midgut, has established Drosophila as an exciting model to study stem cell-mediated adult tissue homeostasis and regeneration. Here, we review the major signaling pathways that regulate the self-renewal, proliferation and differentiation of Drosophila ISCs, discussing how this regulation maintains midgut homeostasis and mediates regeneration of the intestinal epithelium after injury. -- Highlights:more » Black-Right-Pointing-Pointer The homeostasis and regeneration of adult fly midguts are mediated by ISCs. Black-Right-Pointing-Pointer Damaged enterocytes induce the proliferation of intestinal stem cells (ISC). Black-Right-Pointing-Pointer EGFR and Jak/Stat signalings mediate compensatory ISC proliferation. Black-Right-Pointing-Pointer Notch signaling regulates ISC self-renewal and differentiation.« less

Informatic and genomic analysis of melanocyte cDNA libraries as a resource for the study of melanocyte development and function.

PubMed

Baxter, Laura L; Hsu, Benjamin J; Umayam, Lowell; Wolfsberg, Tyra G; Larson, Denise M; Frith, Martin C; Kawai, Jun; Hayashizaki, Yoshihide; Carninci, Piero; Pavan, William J

2007-06-01

As part of the RIKEN mouse encyclopedia project, two cDNA libraries were prepared from melanocyte-derived cell lines, using techniques of full-length clone selection and subtraction/normalization to enrich for rare transcripts. End sequencing showed that these libraries display over 83% complete coding sequence at the 5' end and 96-97% complete coding sequence at the 3' end. Evaluation of the libraries, derived from B16F10Y tumor cells and melan-c cells, revealed that they contain clones for a majority of the genes previously demonstrated to function in melanocyte biology. Analysis of genomic locations for transcripts revealed that the distribution of melanocyte genes is non-random throughout the genome. Three genomic regions identified that showed significant clustering of melanocyte-expressed genes contain one or more genes previously shown to regulate melanocyte development or function. A catalog of genes expressed in these libraries is presented, providing a valuable resource of cDNA clones and sequence information that can be used for identification of new genes important for melanocyte development, function, and disease.

Adult Mammalian Neural Stem Cells and Neurogenesis: Five Decades Later

PubMed Central

Bond, Allison M.; Ming, Guo-li; Song, Hongjun

2015-01-01

Summary Adult somatic stem cells in various organs maintain homeostatic tissue regeneration and enhance plasticity. Since its initial discovery five decades ago, investigations of adult neurogenesis and neural stem cells have led to an established and expanding field that has significantly influenced many facets of neuroscience, developmental biology and regenerative medicine. Here we review recent progress and focus on questions related to adult mammalian neural stem cells that also apply to other somatic stem cells. We further discuss emerging topics that are guiding the field toward better understanding adult neural stem cells and ultimately applying these principles to improve human health. PMID:26431181

Adult neural stem cells: The promise of the future

PubMed Central

Taupin, Philippe

2007-01-01

Stem cells are self-renewing undifferentiated cells that give rise to multiple types of specialized cells of the body. In the adult, stem cells are multipotents and contribute to homeostasis of the tissues and regeneration after injury. Until recently, it was believed that the adult brain was devoid of stem cells, hence unable to make new neurons and regenerate. With the recent evidences that neurogenesis occurs in the adult brain and neural stem cells (NSCs) reside in the adult central nervous system (CNS), the adult brain has the potential to regenerate and may be amenable to repair. The function(s) of NSCs in the adult CNS remains the source of intense research and debates. The promise of the future of adult NSCs is to redefine the functioning and physiopathology of the CNS, as well as to treat a broad range of CNS diseases and injuries. PMID:19300610

Autophagy as a melanocytic self-defense mechanism.

PubMed

Setaluri, Vijayasaradhi

2015-05-01

Defects in autophagy have implications for melanocyte survival and manifestations of skin pigmentary disorders. Zhang et al. (2015) show that mouse melanocytes lacking the autophagy protein Atg7 undergo premature senescence in vitro and accumulate products of oxidative damage, despite activation of the redox response. Interestingly, contrary to previous findings, the melanocyte-specific deficiency in autophagy did not cause major defects in melanosome biogenesis, nor did it produce visually striking changes in mouse coat color.

Neuroendocrine activity of the melanocyte

PubMed Central

Slominski, Andrzej

2009-01-01

More than 15 years ago, we have proposed that melanocytes are sensory and regulatory cells with computing capability, which transform external and/or internal signals/energy into organized regulatory network(s) for the maintenance of the cutaneous homeostasis. This concept is substantiated by accumulating evidence that melanocytes produce classical stress neurotransmitters, neuropeptides and hormones, express corresponding receptors and these processes are modified and/or regulated by ultraviolet radiation, biological factors or stress. Examples of the above are catecholamines, serotonin, N-acetyl-serotonin, melatonin, proopiomelanocortin-derived adrenocorticotropic hormone, β-endorphin or melanocyte-stimulating hormone peptides, corticotropin releasing factor, related urocortins and corticosteroids including cortisol and corticosterone as well as their precursors. Furthermore, their production is not random, but hierarchical and follows the structures of classical neuroendocrine organizations such as hypothalamic-pituitary-adrenal axis, serotoninergic, melatoninergic and catecholaminergic systems. An example of an intrinsic but overlooked neuroendocrine activity is production and secretion of melanogenesis intermediates including L-DOPA or its derivatives that could enter circulation and act on distant sites. Such capabilities have defined melanocytes as neuroendocrine cells that not only coordinate cutaneous but also can affect a global homeostasis. PMID:19558501

Identification and isolation of adult liver stem/progenitor cells.

PubMed

Tanaka, Minoru; Miyajima, Atsushi

2012-01-01

Hepatoblasts are considered to be liver stem/progenitor cells in the fetus because they propagate and differentiate into two types of liver epithelial cells, hepatocytes and cholangiocytes. In adults, oval cells that emerge in severely injured liver are considered facultative hepatic stem/progenitor cells. However, the nature of oval cells has remained unclear for long time due to the lack of a method to isolate them. It has also been unclear whether liver stem/progenitor cells exist in normal adult liver. Recently, we and others have successfully identified oval cells and adult liver stem/progenitor cells. Here, we describe the identification and isolation of mouse liver stem/progenitor cells by utilizing antibodies against specific cell surface marker molecules.

Early diagnosis and successful treatment of paraneoplastic melanocytic proliferation

PubMed Central

Jansen, Joyce C G; Van Calster, Joachim; Pulido, Jose S; Miles, Sarah L; Vile, Richard G; Van Bergen, Tine; Cassiman, Catherine; Spielberg, Leigh H; Leys, Anita M

2015-01-01

Background Paraneoplastic melanocytic proliferation (bilateral diffuse uveal melanocytic proliferation, BDUMP) is a rare but devastating disease that causes progressive visual loss in patients who usually have an occult malignancy. Visual loss occurs as a result of paraneoplastic changes in the uveal tissue. Methods In a masked fashion, the serum of two patients with BDUMP was evaluated for the presence of cultured melanocyte elongation and proliferation (CMEP) factor using cultured human melanocytes. We evaluated the efficacy of plasmapheresis as a treatment modality early in the disease in conjunction with radiation and chemotherapy. Results The serum of the first case patient was investigated after plasmapheresis and did not demonstrate proliferation of cultured human melanocytes. The serum of the second case was evaluated prior to treatment with plasmapheresis and did induce this proliferation. These findings are in accordance with the diminution of CMEP factor after plasmapheresis. Treatment with plasmapheresis managed to stabilise the ocular disease progression in both patients. Conclusions In the past, visual loss due to paraneoplastic melanocytic proliferation was considered progressive and irreversible. We treated two patients successfully with plasmapheresis and demonstrated a relation between CMEP factor in the serum of these patients and proliferation of cultured melanocytes. PMID:25908835

Keratinocyte-melanocyte interactions during melanosome transfer.

PubMed

Seiberg, M

2001-08-01

The epidermal-melanin unit is composed of one melanocyte and approximately 36 neighboring keratinocytes, working in synchrony to produce and distribute melanin. Melanin is synthesized in melanosomes, transferred to the dendrite tips, and translocated into keratinocytes, forming caps over the keratinocyte nuclei. The molecular and cellular mechanisms involved in melanosome transfer and the keratinocyte-melanocyte interactions required for this process are not yet completely understood. Suggested mechanisms of melanosome transfer include melanosome release and endocytosis, direct inoculation ('injection'), keratinocyte-melanocyte membrane fusion, and phagocytosis. Studies of the keratinocyte receptor protease-activated receptor-2 (PAR-2) support the phagocytosis theory. PAR-2 controls melanosome ingestion and phagocytosis by keratinocytes and exerts a regulatory role in skin pigmentation. Modulation of PAR-2 activity can enhance or decrease melanosome transfer and affects pigmentation only when there is keratinocyte-melanocyte contact. Moreover, PAR-2 is induced by UV irradiation and inhibition of PAR-2 activation results in the prevention of UVB-induced tanning. The role of PAR-2 in mediating UV-induced responses remains to be elucidated.

Melanocyte development: with a message of encouragement to young women scientists.

PubMed

Mizoguchi, Masako

2004-10-01

This is a semi-biographical review describing my research on melanocyte development and related personal experiences. Having been educated and trained as a dermatologist, I have been involved in many clinically-oriented studies, however, what has always interested me the most is pigment cell biology. Since I started working at St Marianna University in 1991, I have been undertaking research on melanocyte development and relevant growth factors using mice as models. My research in this field was inspired by my collaborations with various scientists, mostly from the field of biology. Many of these specialists I have met at meetings of the Societies of Pigment Cell Research (PCR). Stem cell factor (SCF, Kitl) and endothelin 3 (EDN3) have been identified as indispensable factors regulating the development of melanocytes. Mice mutant at loci encoding those factors (or their receptors) such as Sl/Sl (receptors W/W) and ls/ls (receptors s/s) have white coat colors and white patches, respectively. Our murine neural crest cell (NCC) primary cultures derived from Sl/Sl embryos showed that EDN3 cannot develop melanocyte precursors without SCF and that EDN3 can elicit proliferation and differentiation in the presence of SCF. These results suggest that without EDN3 and the endothelin type B receptor (EDNRB), melanocytes can not fully increase in number, which could well be the cause of the partial white coat color of ls/ls and s/s mice. Contamination with factors derived from the serum in medium or in feeder cells sometimes causes experimental errors, and therefore we established three immortal cell lines derived from NCC in different developmental stages and designated them as NCCmelb4, NCCmelb4M5 and NCCmelan5, all of which can survive without feeder cells. Using these cell lines and NCC primary cultures, we studied the effect of many factors related to melanocyte development. From the results, it has become evident that Vitamin D3 induces EDNRB expression by NCCmelb4 cells

Muscle Stem Cells: A Model System for Adult Stem Cell Biology.

PubMed

Cornelison, Ddw; Perdiguero, Eusebio

2017-01-01

Skeletal muscle stem cells, originally termed satellite cells for their position adjacent to differentiated muscle fibers, are absolutely required for the process of skeletal muscle repair and regeneration. In the last decade, satellite cells have become one of the most studied adult stem cell systems and have emerged as a standard model not only in the field of stem cell-driven tissue regeneration but also in stem cell dysfunction and aging. Here, we provide background in the field and discuss recent advances in our understanding of muscle stem cell function and dysfunction, particularly in the case of aging, and the potential involvement of muscle stem cells in genetic diseases such as the muscular dystrophies.

The longest telomeres: a general signature of adult stem cell compartments

PubMed Central

Flores, Ignacio; Canela, Andres; Vera, Elsa; Tejera, Agueda; Cotsarelis, George; Blasco, María A.

2008-01-01

Identification of adult stem cells and their location (niches) is of great relevance for regenerative medicine. However, stem cell niches are still poorly defined in most adult tissues. Here, we show that the longest telomeres are a general feature of adult stem cell compartments. Using confocal telomere quantitative fluorescence in situ hybridization (telomapping), we find gradients of telomere length within tissues, with the longest telomeres mapping to the known stem cell compartments. In mouse hair follicles, we show that cells with the longest telomeres map to the known stem cell compartments, colocalize with stem cell markers, and behave as stem cells upon treatment with mitogenic stimuli. Using K15-EGFP reporter mice, which mark hair follicle stem cells, we show that GFP-positive cells have the longest telomeres. The stem cell compartments in small intestine, testis, cornea, and brain of the mouse are also enriched in cells with the longest telomeres. This constitutes the description of a novel general property of adult stem cell compartments. Finally, we make the novel finding that telomeres shorten with age in different mouse stem cell compartments, which parallels a decline in stem cell functionality, suggesting that telomere loss may contribute to stem cell dysfunction with age. PMID:18283121

Early diagnosis and successful treatment of paraneoplastic melanocytic proliferation.

PubMed

Jansen, Joyce C G; Van Calster, Joachim; Pulido, Jose S; Miles, Sarah L; Vile, Richard G; Van Bergen, Tine; Cassiman, Catherine; Spielberg, Leigh H; Leys, Anita M

2015-07-01

Paraneoplastic melanocytic proliferation (bilateral diffuse uveal melanocytic proliferation, BDUMP) is a rare but devastating disease that causes progressive visual loss in patients who usually have an occult malignancy. Visual loss occurs as a result of paraneoplastic changes in the uveal tissue. In a masked fashion, the serum of two patients with BDUMP was evaluated for the presence of cultured melanocyte elongation and proliferation (CMEP) factor using cultured human melanocytes. We evaluated the efficacy of plasmapheresis as a treatment modality early in the disease in conjunction with radiation and chemotherapy. The serum of the first case patient was investigated after plasmapheresis and did not demonstrate proliferation of cultured human melanocytes. The serum of the second case was evaluated prior to treatment with plasmapheresis and did induce this proliferation. These findings are in accordance with the diminution of CMEP factor after plasmapheresis. Treatment with plasmapheresis managed to stabilise the ocular disease progression in both patients. In the past, visual loss due to paraneoplastic melanocytic proliferation was considered progressive and irreversible. We treated two patients successfully with plasmapheresis and demonstrated a relation between CMEP factor in the serum of these patients and proliferation of cultured melanocytes. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Iris melanocyte numbers in Asian, African American, and Caucasian irides.

PubMed Central

Albert, Daniel M; Green, W Richard; Zimbric, Michele L; Lo, Cecilia; Gangnon, Ronald E; Hope, Kirsten L; Gleiser, Joel

2003-01-01

PURPOSE: The anatomical basis for iris color has long been a controversial issue in ophthalmology. Recent studies demonstrated that in Caucasians, blue-eyed, gray-eyed, and hazel-eyed individuals have comparable numbers of iris melanocytes. The present investigation was carried out to compare melanocyte numbers in the irides of Asian, African American, and Caucasian brown-eyed individuals. METHODS: Paraffin-embedded sections from 71 brown-colored irides were incubated with rabbit anti-cow antibody against S100a, linked with an FITC conjugate antibody, and counterstained with Evans blue. Cells were counted under a fluorescence microscope and scored as melanocytes or other cells. Cell number, density, and iris area were calculated for each specimen. RESULTS: Caucasian and African American irides had comparable mean total melanocyte numbers. Asian irides had fewer total melanocytes than African American (P = .042) and Caucasian (P = .001) irides and smaller total number of cells (ie, melanocytes plus other cells) than African American (P = .054) or Caucasian (P = .009) irides. CONCLUSIONS: There is a statistically significant smaller mean total melanocyte number and mean total cellularity in Asian irides as compared to Caucasian and African American irides. This difference appears to be due to the combination of smaller iris area and lower melanocyte density in the Asian irides. The possibility exists that this may be a factor in ethnic variations in certain ocular diseases. PMID:14971580

Expansion of Multipotent Stem Cells from the Adult Human Brain

PubMed Central

Murrell, Wayne; Palmero, Emily; Bianco, John; Stangeland, Biljana; Joel, Mrinal; Paulson, Linda; Thiede, Bernd; Grieg, Zanina; Ramsnes, Ingunn; Skjellegrind, Håvard K.; Nygård, Ståle; Brandal, Petter; Sandberg, Cecilie; Vik-Mo, Einar; Palmero, Sheryl; Langmoen, Iver A.

2013-01-01

The discovery of stem cells in the adult human brain has revealed new possible scenarios for treatment of the sick or injured brain. Both clinical use of and preclinical research on human adult neural stem cells have, however, been seriously hampered by the fact that it has been impossible to passage these cells more than a very few times and with little expansion of cell numbers. Having explored a number of alternative culturing conditions we here present an efficient method for the establishment and propagation of human brain stem cells from whatever brain tissue samples we have tried. We describe virtually unlimited expansion of an authentic stem cell phenotype. Pluripotency proteins Sox2 and Oct4 are expressed without artificial induction. For the first time multipotency of adult human brain-derived stem cells is demonstrated beyond tissue boundaries. We characterize these cells in detail in vitro including microarray and proteomic approaches. Whilst clarification of these cells’ behavior is ongoing, results so far portend well for the future repair of tissues by transplantation of an adult patient’s own-derived stem cells. PMID:23967194

Proton Beam Radiation Therapy in Treating Patients With Low Grade Gliomas

ClinicalTrials.gov

2015-12-14

Adult Brain Tumor; Adult Brain Stem Glioma; Adult Diffuse Astrocytoma; Adult Ependymoma; Adult Grade II Meningioma; Adult Melanocytic Lesion; Adult Meningeal Hemangiopericytoma; Adult Mixed Glioma; Adult Oligodendroglioma; Adult Pineal Gland Astrocytoma; Adult Pineocytoma; Recurrent Adult Brain Tumor

YY1 Regulates Melanocyte Development and Function by Cooperating with MITF

PubMed Central

Bell, Robert J. A.; Tran, Thanh-Nga T.; Haq, Rizwan; Liu, Huifei; Love, Kevin T.; Langer, Robert; Anderson, Daniel G.; Larue, Lionel; Fisher, David E.

2012-01-01

Studies of coat color mutants have greatly contributed to the discovery of genes that regulate melanocyte development and function. Here, we generated Yy1 conditional knockout mice in the melanocyte-lineage and observed profound melanocyte deficiency and premature gray hair, similar to the loss of melanocytes in human piebaldism and Waardenburg syndrome. Although YY1 is a ubiquitous transcription factor, YY1 interacts with M-MITF, the Waardenburg Syndrome IIA gene and a master transcriptional regulator of melanocytes. YY1 cooperates with M-MITF in regulating the expression of piebaldism gene KIT and multiple additional pigmentation genes. Moreover, ChIP–seq identified genome-wide YY1 targets in the melanocyte lineage. These studies mechanistically link genes implicated in human conditions of melanocyte deficiency and reveal how a ubiquitous factor (YY1) gains lineage-specific functions by co-regulating gene expression with a lineage-restricted factor (M-MITF)—a general mechanism which may confer tissue-specific gene expression in multiple lineages. PMID:22570637

Stem cell sources for clinical islet transplantation in type 1 diabetes: embryonic and adult stem cells.

PubMed

Miszta-Lane, Helena; Mirbolooki, Mohammadreza; James Shapiro, A M; Lakey, Jonathan R T

2006-01-01

Lifelong immunosuppressive therapy and inadequate sources of transplantable islets have led the islet transplantation benefits to less than 0.5% of type 1 diabetics. Whereas the potential risk of infection by animal endogenous viruses limits the uses of islet xeno-transplantation, deriving islets from stem cells seems to be able to overcome the current problems of islet shortages and immune compatibility. Both embryonic (derived from the inner cell mass of blastocysts) and adult stem cells (derived from adult tissues) have shown controversial results in secreting insulin in vitro and normalizing hyperglycemia in vivo. ESCs research is thought to have much greater developmental potential than adult stem cells; however it is still in the basic research phase. Existing ESC lines are not believed to be identical or ideal for generating islets or beta-cells and additional ESC lines have to be established. Research with ESCs derived from humans is controversial because it requires the destruction of a human embryo and/or therapeutic cloning, which some believe is a slippery slope to reproductive cloning. On the other hand, adult stem cells are already in some degree specialized, recipients may receive their own stem cells. They are flexible but they have shown mixed degree of availability. Adult stem cells are not pluripotent. They may not exist for all organs. They are difficult to purify and they cannot be maintained well outside the body. In order to draw the future avenues in this field, existent discrepancies between the results need to be clarified. In this study, we will review the different aspects and challenges of using embryonic or adult stem cells in clinical islet transplantation for the treatment of type 1 diabetes.

Concise Review: Adult Mesenchymal Stem Cells, Adult Neural Crest Stem Cells, and Therapy of Neurological Pathologies: A State of Play

PubMed Central

Neirinckx, Virginie; Coste, Cécile; Rogister, Bernard

2013-01-01

Adult stem cells are endowed with in vitro multilineage differentiation abilities and constitute an attractive autologous source of material for cell therapy in neurological disorders. With regard to lately published results, the ability of adult mesenchymal stem cells (MSCs) and neural crest stem cells (NCSCs) to integrate and differentiate into neurons once inside the central nervous system (CNS) is currently questioned. For this review, we collected exhaustive data on MSC/NCSC neural differentiation in vitro. We then analyzed preclinical cell therapy experiments in different models for neurological diseases and concluded that neural differentiation is probably not the leading property of adult MSCs and NCSCs concerning neurological pathology management. A fine analysis of the molecules that are secreted by MSCs and NCSCs would definitely be of significant interest regarding their important contribution to the clinical and pathological recovery after CNS lesions. PMID:23486833

Therapeutics from Adult Stem Cells and the Hype Curve.

PubMed

Maguire, Greg

2016-05-12

The Gartner curve for regenerative and stem cell therapeutics is currently climbing out of the "trough of disillusionment" and into the "slope of enlightenment". Understanding that the early years of stem cell therapy relied on the model of embryonic stem cells (ESCs), and then moved into a period of the overhype of induced pluripotent stem cells (iPSCs), instead of using the model of 40 years of success, i.e. adult stem cells used in bone marrow transplants, the field of stem cell therapy has languished for years, trying to move beyond the early and poorly understood success of bone marrow transplants. Recent studies in the lab and clinic show that adult stem cells of various types, and the molecules that they release, avoid the issues associated with ESCs and iPSCs and lead to better therapeutic outcomes and into the slope of enlightenment.

PREFERENTIAL SECRETION OF INDUCIBLE HSP70 BY VITILIGO MELANOCYTES UNDER STRESS

PubMed Central

Mosenson, Jeffrey A.; Flood, Kelsey; Klarquist, Jared; Eby, Jonathan M.; Koshoffer, Amy; Boissy, Raymond E.; Overbeck, Andreas; C.Tung, Rebecca; Poole, I. Caroline Le

2014-01-01

SUMMARY Inducible HSP70 (HSP70i) chaperones peptides from stressed cells, protecting them from apoptosis. Upon extracellular release, HSP70i serves an adjuvant function, enhancing immune responses to bound peptides. We questioned whether HSP70i differentially protects control and vitiligo melanocytes from stress and subsequent immune responses. We compared expression of HSP70i in skin samples, evaluated the viability of primary vitiligo and control melanocytes exposed to bleaching phenols, and measured secreted HSP70i. We determined whether HSP70i traffics to melanosomes to contact immunogenic proteins by cell fractionation, western blotting, electron microscopy and confocal microscopy. Viability of vitiligo and control melanocytes was equally affected under stress. However, vitiligo melanocytes secreted increased amounts of HSP70i in response to MBEH, corroborating with aberrant HSP70i expression in patient skin. Intracellular HSP70i colocalized with melanosomes, and more so in response to MBEH in vitiligo melanocytes. Thus whereas either agent is cytotoxic to melanocytes, MBEH preferentially induces immune responses to melanocytes. PMID:24354861

Altered E-Cadherin Levels and Distribution in Melanocytes Precede Clinical Manifestations of Vitiligo.

PubMed

Wagner, Roselyne Y; Luciani, Flavie; Cario-André, Muriel; Rubod, Alain; Petit, Valérie; Benzekri, Laila; Ezzedine, Khaled; Lepreux, Sébastien; Steingrimsson, Eirikur; Taieb, A; Gauthier, Yvon; Larue, Lionel; Delmas, Véronique

2015-07-01

Vitiligo is the most common depigmenting disorder resulting from the loss of melanocytes from the basal epidermal layer. The pathogenesis of the disease is likely multifactorial and involves autoimmune causes, as well as oxidative and mechanical stress. It is important to identify early events in vitiligo to clarify pathogenesis, improve diagnosis, and inform therapy. Here, we show that E-cadherin (Ecad), which mediates the adhesion between melanocytes and keratinocytes in the epidermis, is absent from or discontinuously distributed across melanocyte membranes of vitiligo patients long before clinical lesions appear. This abnormality is associated with the detachment of the melanocytes from the basal to the suprabasal layers in the epidermis. Using human epidermal reconstructed skin and mouse models with normal or defective Ecad expression in melanocytes, we demonstrated that Ecad is required for melanocyte adhesiveness to the basal layer under oxidative and mechanical stress, establishing a link between silent/preclinical, cell-autonomous defects in vitiligo melanocytes and known environmental stressors accelerating disease expression. Our results implicate a primary predisposing skin defect affecting melanocyte adhesiveness that, under stress conditions, leads to disappearance of melanocytes and clinical vitiligo. Melanocyte adhesiveness is thus a potential target for therapy aiming at disease stabilization.

Poised Regeneration of Zebrafish Melanocytes Involves Direct Differentiation and Concurrent Replenishment of Tissue-Resident Progenitor Cells.

PubMed

Iyengar, Sharanya; Kasheta, Melissa; Ceol, Craig J

2015-06-22

Efficient regeneration following injury is critical for maintaining tissue function and enabling organismal survival. Cells reconstituting damaged tissue are often generated from resident stem or progenitor cells or from cells that have dedifferentiated and become proliferative. While lineage-tracing studies have defined cellular sources of regeneration in many tissues, the process by which these cells execute the regenerative process is largely obscure. Here, we have identified tissue-resident progenitor cells that mediate regeneration of zebrafish stripe melanocytes and defined how these cells reconstitute pigmentation. Nearly all regeneration melanocytes arise through direct differentiation of progenitor cells. Wnt signaling is activated prior to differentiation, and inhibition of Wnt signaling impairs regeneration. Additional progenitors divide symmetrically to sustain the pool of progenitor cells. Combining direct differentiation with symmetric progenitor divisions may serve as a means to rapidly repair injured tissue while preserving the capacity to regenerate. Copyright © 2015 Elsevier Inc. All rights reserved.

Melanogenesis in dermal melanocytes of Japanese Silky chicken embryos.

PubMed

Ortolani-Machado, C F; Freitas, P F; Faraco, C D

2009-08-01

The Japanese Silky chicken (SK) shows dermal and visceral hyperpigmentation. This study characterizes ultrastructurally the melanin granules developing in dermal melanocytes of the dorsal skin of SK, in an attempt to better understand the processes of melanogenesis in these permanently ectopic cells. The steps of melanogenesis are similar to those described for epidermal melanocytes, with melanosomes going from stage I to IV but, in SK, the maturation occurs in the cell body, as well as in the cytoplasmic processes. At stage III, the deposition of melanin is cumulative and can aggregate in rounded structures, which combine to turn into the mature granule. The final destiny of mature melanosomes is still unclear, although it was observed that dermal macrophages can accumulate melanin granules in their phagosomes. Even with the close proximity between melanocytes and other dermal cells, the transference of melanosomes was not observed. Our findings indicate that melanogenesis in dermal melanocytes in SK has the same morphological characteristics found in epidermal melanocytes, but the functional aspect still remains to be elucidated.

Protective effects of glutamine on human melanocyte oxidative stress model.

PubMed

Jiang, Liya; Guo, Zhen; Kong, Yulong; Liang, Jianhua; Wang, Yi; Wang, Keyu

2018-01-01

Vitiligo is a disorder caused by the loss of the melanocyte activity on melanin pigment generation. Studies show that oxidative-stress induced apoptosis in melanocytes is closely related to the pathogenesis of vitiligo. Glutamine is a well known antioxidant with anti-apoptotic effects, and is used in a variety of diseases. However, it is unclear whether glutamine has an antioxidant or anti-apoptotic effect on melanocytes. The aim of this study was to investigate the protective effects of glutamine on a human melanocyte oxidative stress model. The oxidative stress model was established on human melanocytes using hydrogen peroxide. The morphology and viability of melanocytes, levels of oxidants [reactive oxygen species and malondialdehyde], levels of antioxidants [superoxide dismutase and glutathione-S-transferase], and apoptosis-related indicators (caspase-3, bax and bcl-2) were examined after glutamine exposure at various concentrations. Expressions of nuclear factor-E2-related factor 2, heme oxygenase-1, and heat shock protein 70 were detected using western blot technique after glutamine exposure at various concentrations. Our results demonstrate that pre-treatment and post-treatment with glutamine promoted melanocyte viability, increased levels of superoxide dismutase, glutathione-S-transferase and bcl-2, decreased levels of reactive oxygen species, malondialdehyde, bax and caspase-3, and enhanced nuclear factor-E2-related factor 2, heme oxygenase-1, and heat shock protein 70 expression in a dose dependent manner. The effect of pre-treatment was more significant than post-treatment, at the same concentration. The mechanisms of glutamine activated nuclear factor-E2-related factor 2 antioxidant responsive element signaling pathway need further investigation. Glutamine enhances the antioxidant and anti-apoptotic capabilities of melanocytes and protects them against oxidative stress.

Cerebellar stem cells do not produce neurons and astrocytes in adult mouse

DOE Office of Scientific and Technical Information (OSTI.GOV)

Su, Xin; Guan, Wuqiang; Yu, Yong-Chun

Highlights: • No new neurons and astrocytes are generated in adult mouse cerebellum. • Very few mash1{sup +} or nestin{sup +} stem cells exist, and most of them are quiescent. • Cell proliferation rate is diversified among cerebellar regions and decreases over time. - Abstract: Although previous studies implied that cerebellar stem cells exist in some adult mammals, little is known about whether these stem cells can produce new neurons and astrocytes. In this study by bromodeoxyuridine (BrdU) intraperitoneal (i.p.) injection, we found that there are abundant BrdU{sup +} cells in adult mouse cerebellum, and their quantity and density decreasesmore » significantly over time. We also found cell proliferation rate is diversified in different cerebellar regions. Among these BrdU{sup +} cells, very few are mash1{sup +} or nestin{sup +} stem cells, and the vast majority of cerebellar stem cells are quiescent. Data obtained by in vivo retrovirus injection indicate that stem cells do not produce neurons and astrocytes in adult mouse cerebellum. Instead, some cells labeled by retrovirus are Iba1{sup +} microglia. These results indicate that very few stem cells exist in adult mouse cerebellum, and none of these stem cells contribute to neurogenesis and astrogenesis under physiological condition.« less

Melanocytic Ophthalmic Neoplasms of the Domestic Veterinary Species: A Review.

PubMed

Wang, Annie L; Kern, Thomas

2015-12-01

Melanocytic neoplasms in veterinary species occur in various ophthalmic locations including the eyelid, conjunctiva, cornea, sclera, anterior and posterior uvea, and orbit. Histology usually provides the definitive diagnosis for melanocytic ocular neoplasias. The degree of tissue invasiveness and anaplastic cellular characteristics are more reliable indicators of biological behavior than is mitotic index in most ophthalmic melanocytic tumors. Melanocytic neoplasias of the eyelid are predominantly benign in canines and equines, though in felines, there is the potential for metastasis, especially if the conjunctiva is involved. Limbal melanocytic tumors are predominantly benign in all the studied species, though there is a bimodal occurrence with this tumor type in canines, where those that appear in dogs younger than 4 years tended toward active growth, whereas those that appear in dogs older than 8 years tended to progress more slowly, and may not require therapy. The most common location for melanocytic ocular neoplasias in both canines and felines is the anterior uvea. Feline diffuse iris melanoma in particular has a higher incidence of metastasis than does canine nodular anterior uveal melanocytoma. In contrast, posterior uveal melanocytic tumors are rare in both canine and feline species and are considered benign. Orbital melanoma is rare in both canine and feline species; however, it generally carries a grave prognosis owing to its malignant nature. Knowledge of the general biological behavior and its variability among locations within the eye and between species is essential in therapeutic planning. Copyright © 2016 Elsevier Inc. All rights reserved.

Sox10+ adult stem cells contribute to biomaterial encapsulation and microvascularization

PubMed Central

Wang, Dong; Wang, Aijun; Wu, Fan; Qiu, Xuefeng; Li, Ye; Chu, Julia; Huang, Wen-Chin; Xu, Kang; Gong, Xiaohua; Li, Song

2017-01-01

Implanted biomaterials and biomedical devices generally induce foreign body reaction and end up with encapsulation by a dense avascular fibrous layer enriched in extracellular matrix. Fibroblasts/myofibroblasts are thought to be the major cell type involved in encapsulation, but it is unclear whether and how stem cells contribute to this process. Here we show, for the first time, that Sox10+ adult stem cells contribute to both encapsulation and microvessel formation. Sox10+ adult stem cells were found sparsely in the stroma of subcutaneous loose connective tissues. Upon subcutaneous biomaterial implantation, Sox10+ stem cells were activated and recruited to the biomaterial scaffold, and differentiated into fibroblasts and then myofibroblasts. This differentiation process from Sox10+ stem cells to myofibroblasts could be recapitulated in vitro. On the other hand, Sox10+ stem cells could differentiate into perivascular cells to stabilize newly formed microvessels. Sox10+ stem cells and endothelial cells in three-dimensional co-culture self-assembled into microvessels, and platelet-derived growth factor had chemotactic effect on Sox10+ stem cells. Transplanted Sox10+ stem cells differentiated into smooth muscle cells to stabilize functional microvessels. These findings demonstrate the critical role of adult stem cells in tissue remodeling and unravel the complexity of stem cell fate determination. PMID:28071739

Pigmented basal cell carcinoma: increased melanin or increased melanocytes?

PubMed

Brankov, Nikoleta; Prodanovic, Edward M; Hurley, M Yadira

2016-12-01

Studies on the precise cause of increased melanization in pigmented basal cell carcinomas (BCC) are limited. We aimed to determine whether the cause of melanization is from increased number of melanocytes or increased melanin pigment, and if there is a difference in the number of melanocytes on different sun-exposed locations. A retrospective review of 45 skin biopsies from January 2011 to February 2011 was performed; 30 were diagnosed as pigmented BCC and 15 as non-pigmented BCC. Immunohistochemistry for MART-1 (melanoma-associated antigen recognized by T-cell 1)/Melan-A (clone M2-7610 + M2-9E3; Leica Microsystems Inc. Buffalo Grove, IL, USA) from Biocare Medical (Concord, CA, USA) was performed on all biopsies. Associations between histopathologic features, number of melanocytes, location, and specific diagnoses were analyzed by Mann-Whitney U test. The mean melanocyte count per high powered field in pigmented BCCs from sun-exposed skin was 101.9 and from intermittently sun-exposed skin was 122.5, as compared to the controls (nodular non-pigmented BCC) of 27.4 (p = 0.002) and 34.9 (p = 0.002), respectively. Pigmented BCCs have a higher mean melanocyte count as compared to non-pigmented BCCs irrespective of location. Therefore, the pigment is not only due to increased melanin, but also due to increased melanocytes. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

State performance in pluripotent and adult stem cell research, 2009-2016.

PubMed

Surani, Sana H; Levine, Aaron D

2018-04-01

To examine how the geographic distribution of pluripotent and adult stem cell research publications within the USA differs from other areas of biomedical research. Publication count data for pluripotent stem cell research, adult stem cell research and a comparison group representative of biomedical research more broadly were collected and analyzed for each US state from 2009 to 2016. The distribution of pluripotent stem cell research differed from the other fields with overperformance in pluripotent stem cell research observed in California, as well as Wisconsin, Massachusetts, Maryland and Connecticut. Our analysis suggests that permissive state stem cell policy may be one of the several factors contributing to strong state performance in pluripotent stem cell research.

Proteinase-activated receptor-2 stimulates prostaglandin production in keratinocytes: analysis of prostaglandin receptors on human melanocytes and effects of PGE2 and PGF2alpha on melanocyte dendricity.

PubMed

Scott, Glynis; Leopardi, Sonya; Printup, Stacey; Malhi, Namrita; Seiberg, Miri; Lapoint, Randi

2004-05-01

Prostaglandins (PG) are key mediators of diverse functions in the skin and several reports suggest that PG mediate post-inflammatory pigmentary changes through modulation of melanocyte dendricity and melanin synthesis. The proteinase-activated receptor 2 (PAR-2) is important for skin pigmentation because activation of keratinocyte PAR-2 stimulates uptake of melanosomes through phagocytosis in a Rho-dependent manner. In this report, we show that activation of keratinocyte PAR-2 stimulates release of PGE(2) and PGF(2alpha) and that PGE(2) and PGF(2alpha) act as paracrine factors that stimulate melanocyte dendricity. We characterized the expression of the EP and FP receptors in human melanocytes and show that human melanocytes express EP1 and EP3, and the FP receptor, but not EP2 and EP4. Treatment of melanocytes with EP1 and EP3 receptor agonists resulted in increased melanocyte dendricity, indicating that both EP1 and EP3 receptor signaling contribute to PGE(2)-mediated melanocyte dendricity. Certain EP3 receptor subtypes have been shown to increase adenosine 3',5'-cyclic monophosphate (cAMP) through coupling to Gs, whereas EP1 is known to couple to Gq to activate phospholipase C with elevation in Ca(2+). The cAMP/protein kinase A system is known to modulate melanocyte dendrite formation through modulation of Rac and Rho activity. Neither PGF(2alpha) or PGE(2) elevated cAMP in human melanocytes showing that dendricity observed in response to PGE(2) and PGF(2alpha) is cAMP-independent. Our data suggest that PAR-2 mediates cutaneous pigmentation both through increased uptake of melanosomes by keratinocytes, as well as by release of PGE(2) and PGF(2alpha) that stimulate melanocyte dendricity through EP1, EP3, and FP receptors.

Modulation of normal human melanocyte dendricity by growth-promoting agents.

PubMed

Nakazawa, K; Damour, O; Collombel, C

1993-12-01

Dendrite formation and extension, which comprise a characteristic morphology of human normal melanocytes in the skin, represent one of the functional activities of melanocytes, the ability to transfer melanosomes into neighboring keratinocytes. However, the morphology of the melanocyte in vitro is usually quite different from that observed in vivo. it is probably due to the hyperproliferative condition of the melanocytes in culture. No studies have ever compared the effects of a single factor on both dendricity and proliferation at the same time. Therefore, we have compared the effects of six growth-promoting agents commonly used for melanocyte cultures on dendrite formation and proliferation. The addition of agents that increase the intracellular levels of cyclic adenosine monophosphate (cAMP)--dibutyryl cyclic adenosine monophosphate (db cAMP; 1 mM) or isobutylmethyl xanthine (IBMX; 0.1 mM)--had a strong effect on dendrite formation and a negative effect on proliferation. This was especially true with db cAMP. In the presence of 2% or 5% of heat-inactivated fetal bovine serum (FBS), dendrite formation was significantly increased as was proliferation. The number of dendrites was decreased in the culture with 12-o-tetradecanoylphorbol-13-acetate (TPA), but cell growth was slightly increased. With human recombinant basic fibroblast growth factor (bFGF) (0.5, 1.0 ng/ml) in the presence of bovine pituitary extract (BPE) (60 micrograms/ml), cell growth was increased. With 2 ng/ml of bFGF, however, a strong inhibitory effect on proliferation was observed. However, dendrite formation was constant at all concentrations of bFGF tested (0.5, 1.0 or 2.0 ng/ml) with BPE (30 or 60 micrograms/ml). In this study, we have demonstrated that dendrite formation was suppressed by the reagents that stimulate melanocyte proliferation, and vice versa, with the only exception being heat-inactivated FBS. Both dendrite formation and proliferation were induced by the heat-inactivated FBS

Prostaglandin E2 regulates melanocyte dendrite formation through activation of PKCζ

PubMed Central

Scott, Glynis; Fricke, Alex; Fender, Anne; McClelland, Lindy; Jacobs, Stacey

2007-01-01

Prostaglandins are lipid signaling intermediates released by keratinocytes in response to ultraviolet irradiation (UVR) in the skin. The main prostaglandin released following UVR is PGE2, a ligand for 4 related G-protein coupled receptors (EP1, EP2, EP3 and EP4). Our previous work established that PGE2 stimulates melanocyte dendrite formation through activation of the EP1 and EP3 receptors. The purpose of the present report is to define the signaling intermediates involved in EP1 and EP3-dependent dendrite formation in human melanocytes. We recently showed that activation of the atypical PKCζ isoform stimulates melanocyte dendricity in response to treatment with lysophosphatidylcholine. We therefore examined the potential contribution of PKCζ activation on EP1 and EP3-dependent dendrite formation in melanocytes. Stimulation of the EP1 and EP3 receptors by selective agonists activated PKCζ, and inhibition of PKCζ activation abrogated EP1 and EP3-receptor mediated melanocyte dendricity. Because of the importance of Rho-GTP binding proteins in the regulation of melanocyte dendricity, we also examined the effect of EP1 and EP3 receptor activation on Rac and Rho activity. Neither Rac nor Rho was activated upon treatment with EP1,3-receptor agonists. We show that melanocytes express only the EP3A1 isoform, but not the EP3B receptor isoform, previously associated with Rho activation, consistent with a lack of Rho stimulation by EP3 agonists. Our data suggest that PKCζ activation plays a predominant role in regulation of PGE2-dependent melanocyte dendricity. PMID:17850789

Nitric oxide enhances the sensitivity of alpaca melanocytes to respond to {alpha}-melanocyte-stimulating hormone by up-regulating melanocortin-1 receptor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dong, Yanjun; Cao, Jing; Wang, Haidong

2010-06-11

Nitric oxide (NO) and {alpha}-melanocyte-stimulating hormone ({alpha}-MSH) have been correlated with the synthesis of melanin. The NO-dependent signaling of cellular response to activate the hypothalamopituitary proopiomelanocortin system, thereby enhances the hypophysial secretion of {alpha}-MSH to stimulate {alpha}-MSH-receptor responsive cells. In this study we investigated whether an NO-induced pathway can enhance the ability of the melanocyte to respond to {alpha}-MSH on melanogenesis in alpaca skin melanocytes in vitro. It is important for us to know how to enhance the coat color of alpaca. We set up three groups for experiments using the third passage number of alpaca melanocytes: the control culturesmore » were allowed a total of 5 days growth; the UV group cultures like the control group but the melanocytes were then irradiated everyday (once) with 312 mJ/cm{sup 2} of UVB; the UV + L-NAME group is the same as group UV but has the addition of 300 {mu}M L-NAME (every 6 h). To determine the inhibited effect of NO produce, NO produces were measured. To determine the effect of the NO to the key protein and gene of {alpha}-MSH pathway on melanogenesis, the key gene and protein of the {alpha}-MSH pathway were measured by quantitative real-time PCR and Western immunoblotting. The results provide exciting new evidence that NO can enhance {alpha}-MSH pathway in alpaca skin melanocytes by elevated MC1R. And we suggest that the NO pathway may more rapidly cause the synthesis of melanin in alpaca skin under UV, which at that time elevates the expression of MC1R and stimulates the keratinocytes to secrete {alpha}-MSH to enhance the {alpha}-MSH pathway on melanogenesis. This process will be of considerable interest in future studies.« less

Nitric oxide enhances the sensitivity of alpaca melanocytes to respond to alpha-melanocyte-stimulating hormone by up-regulating melanocortin-1 receptor.

PubMed

Dong, Yanjun; Cao, Jing; Wang, Haidong; Zhang, Jie; Zhu, Zhiwei; Bai, Rui; Hao, HuanQing; He, Xiaoyan; Fan, Ruiwen; Dong, Changsheng

2010-06-11

Nitric oxide (NO) and alpha-melanocyte-stimulating hormone (alpha-MSH) have been correlated with the synthesis of melanin. The NO-dependent signaling of cellular response to activate the hypothalamopituitary proopiomelanocortin system, thereby enhances the hypophysial secretion of alpha-MSH to stimulate alpha-MSH-receptor responsive cells. In this study we investigated whether an NO-induced pathway can enhance the ability of the melanocyte to respond to alpha-MSH on melanogenesis in alpaca skin melanocytes in vitro. It is important for us to know how to enhance the coat color of alpaca. We set up three groups for experiments using the third passage number of alpaca melanocytes: the control cultures were allowed a total of 5 days growth; the UV group cultures like the control group but the melanocytes were then irradiated everyday (once) with 312 mJ/cm(2) of UVB; the UV+L-NAME group is the same as group UV but has the addition of 300 microM L-NAME (every 6h). To determine the inhibited effect of NO produce, NO produces were measured. To determine the effect of the NO to the key protein and gene of alpha-MSH pathway on melanogenesis, the key gene and protein of the alpha-MSH pathway were measured by quantitative real-time PCR and Western immunoblotting. The results provide exciting new evidence that NO can enhance alpha-MSH pathway in alpaca skin melanocytes by elevated MC1R. And we suggest that the NO pathway may more rapidly cause the synthesis of melanin in alpaca skin under UV, which at that time elevates the expression of MC1R and stimulates the keratinocytes to secrete alpha-MSH to enhance the alpha-MSH pathway on melanogenesis. This process will be of considerable interest in future studies. (c) 2010 Elsevier Inc. All rights reserved.

Neural stem cell quiescence and stemness are molecularly distinct outputs of the Notch3 signalling cascade in the vertebrate adult brain.

PubMed

Than-Trong, Emmanuel; Ortica-Gatti, Sara; Mella, Sébastien; Nepal, Chirag; Alunni, Alessandro; Bally-Cuif, Laure

2018-05-15

Neural stem cells (NSCs) in the adult vertebrate brain are found in a quiescent state and can preserve long-lasting progenitor potential (stemness). Whether and how these two properties are linked, and to what extent they can be independently controlled by NSC maintenance pathways, is unresolved. We have previously identified Notch3 signalling as a major quiescence-promoting pathway in adult NSCs of the zebrafish pallium. We now show that Notch3 also controls NSC stemness. Using parallel transcriptomic characterizations of notch3 mutant NSCs and adult NSC physiological states, we demonstrate that a set of potentially direct Notch3 target genes distinguishes quiescence and stemness control. As a proof of principle, we focus on one 'stemness' target, encoding the bHLH transcription factor Hey1, that has not yet been analysed in adult NSCs. We show that abrogation of Hey1 function in adult pallial NSCs in vivo , including quiescent NSCs, leads to their differentiation without affecting their proliferation state. These results demonstrate that quiescence and stemness are molecularly distinct outputs of Notch3 signalling, and identify Hey1 as a major Notch3 effector controlling NSC stemness in the vertebrate adult brain. © 2018. Published by The Company of Biologists Ltd.

Melanin: the biophysiology of oral melanocytes and physiological oral pigmentation

PubMed Central

2014-01-01

The presence of melanocytes in the oral epithelium is a well-established fact, but their physiological functions are not well defined. Melanin provides protection from environmental stressors such as ultraviolet radiation and reactive oxygen species; and melanocytes function as stress-sensors having the capacity both to react to and to produce a variety of microenvironmental cytokines and growth factors, modulating immune, inflammatory and antibacterial responses. Melanocytes also act as neuroendocrine cells producing local neurotransmitters including acetylcholine, catecholamines and opioids, and hormones of the melanocortin system such as proopiomelanocortin, adrenocorticotropic hormone and α-melanocyte stimulating hormone, that participate in intracellular and in intercellular signalling pathways, thus contributing to tissue homeostasis. There is a wide range of normal variation in melanin pigmentation of the oral mucosa. In general, darker skinned persons more frequently have oral melanin pigmentation than light-skinned persons. Variations in oral physiological pigmentation are genetically determined unless associated with some underlying disease. In this article, we discuss some aspects of the biophysiology of oral melanocytes, of the functions of melanin, and of physiological oral pigmentation. PMID:24661309

Race Does Not Predict Melanocyte Heterogeneous Responses to Dermal Fibroblast-Derived Mediators

PubMed Central

Sirimahachaiyakul, Pornthep; Sood, Ravi F.; Muffley, Lara A.; Seaton, Max; Lin, Cheng-Ta; Qiao, Liang; Armaly, Jeffrey S.; Hocking, Anne M.; Gibran, Nicole S.

2015-01-01

Introduction Abnormal pigmentation following cutaneous injury causes significant patient distress and represents a barrier to recovery. Wound depth and patient characteristics influence scar pigmentation. However, we know little about the pathophysiology leading to hyperpigmentation in healed shallow wounds and hypopigmentation in deep dermal wound scars. We sought to determine whether dermal fibroblast signaling influences melanocyte responses. Methods and Materials Epidermal melanocytes from three Caucasians and three African-Americans were genotyped for single nucleotide polymorphisms (SNPs) across the entire genome. Melanocyte genetic profiles were determined using principal component analysis. We assessed melanocyte phenotype and gene expression in response to dermal fibroblast-conditioned medium and determined potential mesenchymal mediators by proteome profiling the fibroblast-conditioned medium. Results Six melanocyte samples demonstrated significant variability in phenotype and gene expression at baseline and in response to fibroblast-conditioned medium. Genetic profiling for SNPs in receptors for 13 identified soluble fibroblast-secreted mediators demonstrated considerable heterogeneity, potentially explaining the variable melanocyte responses to fibroblast-conditioned medium. Discussion Our data suggest that melanocytes respond to dermal fibroblast-derived mediators independent of keratinocytes and raise the possibility that mesenchymal-epidermal interactions influence skin pigmentation during cutaneous scarring. PMID:26418010

Regional Fluctuation in the Functional Consequence of LINE-1 Insertion in the Mitf Gene: The Black Spotting Phenotype Arisen from the Mitfmi-bw Mouse Lacking Melanocytes.

PubMed

Takeda, Kazuhisa; Hozumi, Hiroki; Ohba, Koji; Yamamoto, Hiroaki; Shibahara, Shigeki

2016-01-01

Microphthalmia-associated transcription factor (Mitf) is a key regulator for differentiation of melanoblasts, precursors to melanocytes. The mouse homozygous for the black-eyed white (Mitfmi-bw) allele is characterized by the white-coat color and deafness with black eyes due to the lack of melanocytes. The Mitfmi-bw allele carries LINE-1, a retrotransposable element, which results in the Mitf deficiency. Here, we have established the black spotting mouse that was spontaneously arisen from the homozygous Mitfmi-bw mouse lacking melanocytes. The black spotting mouse shows multiple black patches on the white coat, with age-related graying. Importantly, each black patch also contains hair follicles lacking melanocytes, whereas the white-coat area completely lacks melanocytes. RT-PCR analyses of the pigmented patches confirmed that the LINE-1 insertion is retained in the Mitf gene of the black spotting mouse, thereby excluding the possibility of the somatic reversion of the Mitfmi-bw allele. The immunohistochemical analysis revealed that the staining intensity for beta-catenin was noticeably lower in hair follicles lacking melanocytes of the homozygous Mitfmi-bw mouse and the black spotting mouse, compared to the control mouse. In contrast, the staining intensity for beta-catenin and cyclin D1 was higher in keratinocytes of the black spotting mouse, compared to keratinocytes of the control mouse and the Mitfmi-bw mouse. Moreover, the keratinocyte layer appears thicker in the Mitfmi-bw mouse, with the overexpression of Ki-67, a marker for cell proliferation. We also show that the presumptive black spots are formed by embryonic day 15.5. Thus, the black spotting mouse provides the unique model to explore the molecular basis for the survival and death of developing melanoblasts and melanocyte stem cells in the epidermis. These results indicate that follicular melanocytes are responsible for maintaining the epidermal homeostasis; namely, the present study has provided

Regional Fluctuation in the Functional Consequence of LINE-1 Insertion in the Mitf Gene: The Black Spotting Phenotype Arisen from the Mitfmi-bw Mouse Lacking Melanocytes

PubMed Central

Yamamoto, Hiroaki; Shibahara, Shigeki

2016-01-01

Microphthalmia-associated transcription factor (Mitf) is a key regulator for differentiation of melanoblasts, precursors to melanocytes. The mouse homozygous for the black-eyed white (Mitfmi-bw) allele is characterized by the white-coat color and deafness with black eyes due to the lack of melanocytes. The Mitfmi-bw allele carries LINE-1, a retrotransposable element, which results in the Mitf deficiency. Here, we have established the black spotting mouse that was spontaneously arisen from the homozygous Mitfmi-bw mouse lacking melanocytes. The black spotting mouse shows multiple black patches on the white coat, with age-related graying. Importantly, each black patch also contains hair follicles lacking melanocytes, whereas the white-coat area completely lacks melanocytes. RT-PCR analyses of the pigmented patches confirmed that the LINE-1 insertion is retained in the Mitf gene of the black spotting mouse, thereby excluding the possibility of the somatic reversion of the Mitfmi-bw allele. The immunohistochemical analysis revealed that the staining intensity for beta-catenin was noticeably lower in hair follicles lacking melanocytes of the homozygous Mitfmi-bw mouse and the black spotting mouse, compared to the control mouse. In contrast, the staining intensity for beta-catenin and cyclin D1 was higher in keratinocytes of the black spotting mouse, compared to keratinocytes of the control mouse and the Mitfmi-bw mouse. Moreover, the keratinocyte layer appears thicker in the Mitfmi-bw mouse, with the overexpression of Ki-67, a marker for cell proliferation. We also show that the presumptive black spots are formed by embryonic day 15.5. Thus, the black spotting mouse provides the unique model to explore the molecular basis for the survival and death of developing melanoblasts and melanocyte stem cells in the epidermis. These results indicate that follicular melanocytes are responsible for maintaining the epidermal homeostasis; namely, the present study has provided

Neural stem cell quiescence and stemness are molecularly distinct outputs of the Notch3 signalling cascade in the vertebrate adult brain

PubMed Central

Than-Trong, Emmanuel; Ortica-Gatti, Sara; Mella, Sébastien; Nepal, Chirag; Alunni, Alessandro

2018-01-01

ABSTRACT Neural stem cells (NSCs) in the adult vertebrate brain are found in a quiescent state and can preserve long-lasting progenitor potential (stemness). Whether and how these two properties are linked, and to what extent they can be independently controlled by NSC maintenance pathways, is unresolved. We have previously identified Notch3 signalling as a major quiescence-promoting pathway in adult NSCs of the zebrafish pallium. We now show that Notch3 also controls NSC stemness. Using parallel transcriptomic characterizations of notch3 mutant NSCs and adult NSC physiological states, we demonstrate that a set of potentially direct Notch3 target genes distinguishes quiescence and stemness control. As a proof of principle, we focus on one ‘stemness’ target, encoding the bHLH transcription factor Hey1, that has not yet been analysed in adult NSCs. We show that abrogation of Hey1 function in adult pallial NSCs in vivo, including quiescent NSCs, leads to their differentiation without affecting their proliferation state. These results demonstrate that quiescence and stemness are molecularly distinct outputs of Notch3 signalling, and identify Hey1 as a major Notch3 effector controlling NSC stemness in the vertebrate adult brain. PMID:29695612

Melanocyte pigmentation stiffens murine cardiac tricuspid valve leaflet

PubMed Central

Balani, Kantesh; Brito, Flavia C.; Kos, Lidia; Agarwal, Arvind

2009-01-01

Pigmentation of murine cardiac tricuspid valve leaflet is associated with melanocyte concentration, which affects its stiffness. Owing to its biological and viscoelastic nature, estimation of the in situ stiffness measurement becomes a challenging task. Therefore, quasi-static and nanodynamic mechanical analysis of the leaflets of the mouse tricuspid valve is performed in the current work. The mechanical properties along the leaflet vary with the degree of pigmentation. Pigmented regions of the valve leaflet that contain melanocytes displayed higher storage modulus (7–10 GPa) than non-pigmented areas (2.5–4 GPa). These results suggest that the presence of melanocytes affects the viscoelastic properties of the mouse atrioventricular valves and are important for their proper functioning in the organism. PMID:19586956

HPV-Induced Field Cancerisation: Transformation of Adult Tissue Stem Cell Into Cancer Stem Cell.

PubMed

Olivero, Carlotta; Lanfredini, Simone; Borgogna, Cinzia; Gariglio, Marisa; Patel, Girish K

2018-01-01

Field cancerisation was originally described as a basis for multiple head and neck squamous cell carcinoma (HNSCC) and is a pre-malignant phenomenon that is frequently attributable to oncogenic human papillomavirus (HPV) infection. Our work on β-HPV-induced cutaneous squamous cell carcinomas identified a novel Lrig1+ hair follicle junctional zone keratinocyte stem cell population as the basis for field cancerisation. Herein, we describe the ability for HPV to infect adult tissue stem cells in order to establish persistent infection and induce their proliferation and displacement resulting in field cancerisation. By review of the HPV literature, we reveal how this mechanism is conserved as the basis of field cancerisation across many tissues. New insights have identified the capacity for HPV early region genes to dysregulate adult tissue stem cell self-renewal pathways ensuring that the expanded population preserve its stem cell characteristics beyond the stem cell niche. HPV-infected cells acquire additional transforming mutations that can give rise to intraepithelial neoplasia (IEN), from environmental factors such as sunlight or tobacco induced mutations in skin and oral cavity, respectively. With establishment of IEN, HPV viral replication is sacrificed with loss of the episome, and the tissue is predisposed to multiple cancer stem cell-driven carcinomas.

Monitoring human melanocytic cell responses to piperine using multispectral imaging

NASA Astrophysics Data System (ADS)

Samatham, Ravikant; Phillips, Kevin G.; Sonka, Julia; Yelma, Aznegashe; Reddy, Neha; Vanka, Meenakshi; Thuillier, Philippe; Soumyanath, Amala; Jacques, Steven

2011-03-01

Vitiligo is a depigmentary disease characterized by melanocyte loss attributed most commonly to autoimmune mechanisms. Currently vitiligo has a high incidence (1% worldwide) but a poor set of treatment options. Piperine, a compound found in black pepper, is a potential treatment for the depigmentary skin disease vitiligo, due to its ability to stimulate mouse epidermal melanocyte proliferation in vitro and in vivo. The present study investigates the use of multispectral imaging and an image processing technique based on local contrast to quantify the stimulatory effects of piperine on human melanocyte proliferation in reconstructed epidermis. We demonstrate the ability of the imaging method to quantify increased pigmentation in response to piperine treatment. The quantization of melanocyte stimulation by the proposed imaging technique illustrates the potential use of this technology to quickly assess therapeutic responses of vitiligo tissue culture models to treatment non-invasively.

Adult bone marrow-derived stem cells for organ regeneration and repair.

PubMed

Tögel, Florian; Westenfelder, Christof

2007-12-01

Stem cells have been recognized as a potential tool for the development of innovative therapeutic strategies. There are in general two types of stem cells, embryonic and adult stem cells. While embryonic stem cell therapy has been riddled with problems of allogeneic rejection and ethical concerns, adult stem cells have long been used in the treatment of hematological malignancies. With the recognition of additional, potentially therapeutic characteristics, bone marrow-derived stem cells have become a tool in regenerative medicine. The bone marrow is an ideal source of stem cells because it is easily accessible and harbors two types of stem cells. Hematopoietic stem cells give rise to all blood cell types and have been shown to exhibit plasticity, while multipotent marrow stromal cells are the source of osteocytes, chondrocytes, and fat cells and have been shown to support and generate a large number of different cell types. This review describes the general characteristics of these stem cell populations and their current and potential future applications in regenerative medicine. 2007 Wiley-Liss, Inc

Signaling mechanisms regulating adult neural stem cells and neurogenesis

PubMed Central

Faigle, Roland; Song, Hongjun

2012-01-01

Background Adult neurogenesis occurs throughout life in discrete regions of the mammalian brain and is tightly regulated via both extrinsic environmental influences and intrinsic genetic factors. In recent years, several crucial signaling pathways have been identified in regulating self-renewal, proliferation, and differentiation of neural stem cells, as well as migration and functional integration of developing neurons in the adult brain. Scope of review Here we review our current understanding of signaling mechanisms, including Wnt, notch, sonic hedgehog, growth and neurotrophic factors, bone morphogenetic proteins, neurotransmitters, transcription factors, and epigenetic modulators, and crosstalk between these signaling pathways in the regulation of adult neurogenesis. We also highlight emerging principles in the vastly growing field of adult neural stem cell biology and neural plasticity. Major conclusions Recent methodological advances have enabled the field to identify signaling mechanisms that fine-tune and coordinate neurogenesis in the adult brain, leading to a better characterization of both cell-intrinsic and environmental cues defining the neurogenic niche. Significant questions related to niche cell identity and underlying regulatory mechanisms remain to be fully addressed and will be the focus of future studies. General significance A full understanding of the role and function of individual signaling pathways in regulating neural stem cells and generation and integration of newborn neurons in the adult brain may lead to targeted new therapies for neurological diseases in humans. PMID:22982587

Detailed histological structure of human hair follicle bulge region at different ages: a visible niche for nesting adult stem cells.

PubMed

Wang, Xiong; Shi, Ying; Zhou, Qiong; Liu, Xiaoming; Xu, Shizheng; Lei, Tiechi

2012-10-01

In the bulge region of the hair follicle, a densely and concentrically packed cell mass is encircled by the arrector pili muscle (APM), which offers a specilized microenvironment (niche) for housing heterogeneous adult stem cells. However, the detailed histological architecture and the cellular composition of the bulge region warrants intensive study and may have implications for the regulation of hair follicle growth regulation. This study was designed to define the gene-expression profiles of putative stem cells and lineage-specific precursors in the mid-portions of plucked hair follicles prepared according to the presence of detectable autofluorescence. The structure was also characterized by using a consecutive sectioning technique. The bulge region of the hair follicle with autofluorescence was precisely excised by employing a micro-dissection procedure. Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) was performed to identify the gene expression profiles specific for epithelial, melanocyte and stromal stem cells in the bulge region of the hair follicle visualized by autofluorescence. The morphology and its age-dependent changes of bulge region of the hair follicles with autofluorescence segment were also examined in 9 scalp skin specimens collected from patients aged 30 weeks to 75 years, by serial sectioning and immuno-staining. Gene expression profile analysis revealed that there were cells with mRNA transcripts of Dct(Hi)Tyrase(Lo)-Tyrp1(Lo)MC1R(Lo)MITF(Lo)/K15(Hi)/NPNT(Hi) in the bulge region of the hair follicle with autofluorescence segments, which differed from the patterns in hair bulbs. Small cell-protrusions that sprouted from the outer root sheath (ORS) were clearly observed at the APM inserting level in serial sections of hair follicles by immunohistological staining, which were characteristically replete with K15+/K19+expressing cells. Likewise, the muscle bundles of APM positive for smooth muscle actin intimately

Establishment and characterization of a normal melanocyte cell line derived from pig skin.

PubMed

Julé, Sophia; Bossé, Philippe; Egidy, Giorgia; Panthier, Jean-Jacques

2003-08-01

Several minipig strains develop spontaneous malignant melanoma. As a first step toward the analysis of genes involved in the tumoral progression of melanoma in these animal models, we developed culture conditions for pig melanocytes whereby melanocytes from normal epidermis can be isolated directly onto mitotically inactivated keratinocytes in Eagle's minimal essential medium supplemented with fetal calf serum, tetradecanoyl phorbol acetate (TPA) and cholera toxin. We also derived an immortal line of pigmented melanocytes from the epidermis of a healthy Meishan pig. This cell line, designated PigMel, retains differentiation function in culture, dependence on TPA and cholera toxin and a diploid chromosome number. PigMel melanocytes exhibit morphological and molecular characteristics common to normal mammalian skin melanocytes.

Conditional Deletion of Kit in Melanocytes: White Spotting Phenotype Is Cell Autonomous.

PubMed

Aoki, Hitomi; Tomita, Hiroyuki; Hara, Akira; Kunisada, Takahiro

2015-07-01

It is well established that cell-intrinsic signaling through the receptor tyrosine kinase KIT is critical for the development of neural crest-derived melanocytes. Nevertheless, it is not entirely clear whether Kit acts exclusively in a melanocyte-autonomous manner or in addition indirectly through other cell types. To address this question in vivo, we generated a targeted allele of Kit that allowed for CRE recombinase-mediated deletion of the transmembrane domain of KIT. Mice carrying one copy of the targeted allele and expressing CRE under the melanoblast/melanocyte-specific tyrosinase promoter exhibited a white spotting phenotype that was even more extensive compared with that found in mice heterozygous for a Kit-null allele. This phenotype is unlikely the result of sequestration of KIT ligand by neighboring cells or by potentially secreted forms of KIT because the spotting phenotype could not be rescued by overexpression of KITL. Likewise, overexpression of endothelin-3 or hepatocyte growth factor was unable to rescue melanocytes in these mice. Although the severity of the observed phenotype remains to be explained, the findings indicate that melanocyte-selective impairment of Kit is sufficient to interfere with normal melanocyte development.

The Epigenetics of Adult (Somatic) Stem Cells

PubMed Central

Eilertsen, Kenneth J.; Floyd, Z. Elizabeth; Gimble, Jeffrey M.

2009-01-01

While genetic studies have provided a wealth of information about health and disease, there is a growing awareness that individual characteristics are also determined by factors other than genetic sequences. These “epigenetic” changes broadly encompass the influence of the environment on gene regulation and expression and in a more narrow sense, describe the mechanisms controlling DNA methylation, histone modification and genetic imprinting. In this review, we focus on the epigenetic mechanisms that regulate adult (somatic) stem cell differentiation, beginning with the metabolic pathways and factors regulating chromatin structure and DNA methylation and the molecular biological tools that are currently available to study these processes. The role of these epigenetic mechanisms in manipulating adult stem cells is followed by a discussion of the challenges and opportunities facing this emerging field. PMID:18540823

Requirement of zebrafish pcdh10a and pcdh10b in melanocyte precursor migration.

PubMed

Williams, Jason S; Hsu, Jessica Y; Rossi, Christy Cortez; Artinger, Kristin Bruk

2018-03-29

Melanocytes derive from neural crest cells, which are a highly migratory population of cells that play an important role in pigmentation of the skin and epidermal appendages. In most vertebrates, melanocyte precursor cells migrate solely along the dorsolateral pathway to populate the skin. However, zebrafish melanocyte precursors also migrate along the ventromedial pathway, in route to the yolk, where they interact with other neural crest derivative populations. Here, we demonstrate the requirement for zebrafish paralogs pcdh10a and pcdh10b in zebrafish melanocyte precursor migration. pcdh10a and pcdh10b are expressed in a subset of melanocyte precursor and somatic cells respectively, and knockdown and TALEN mediated gene disruption of pcdh10a results in aberrant migration of melanocyte precursors resulting in fully melanized melanocytes that differentiate precociously in the ventromedial pathway. Live cell imaging analysis demonstrates that loss of pchd10a results in a reduction of directed cell migration of melanocyte precursors, caused by both increased adhesion and a loss of cell-cell contact with other migratory neural crest cells. Also, we determined that the paralog pcdh10b is upregulated and can compensate for the genetic loss of pcdh10a. Disruption of pcdh10b alone by CRISPR mutagenesis results in somite defects, while the loss of both paralogs results in enhanced migratory melanocyte precursor phenotype and embryonic lethality. These results reveal a novel role for pcdh10a and pcdh10b in zebrafish melanocyte precursor migration and suggest that pcdh10 paralogs potentially interact for proper transient migration along the ventromedial pathway. Copyright © 2018 Elsevier Inc. All rights reserved.

The effects of IGF1 on the melanogenesis in alpaca melanocytes in vitro.

PubMed

Hu, Shuaipeng; Liu, Yu; Yang, Shanshan; Ji, Kaiyuan; Liu, Xuexian; Zhang, Junzhen; Fan, Ruiwen; Dong, Changsheng

2016-09-01

In order to investigate the effects of the insulin-like growth factor 1(IGF-1) on alpaca melanocyte in vitro, different dosees of IGF1 (0, 10, 20, 40 ng/ml) were added in the medium of alpaca melanocyte. The RTCA machine was used to monitor the proliferation, quantitative real-time PCR, and western blot to test the relative gene expression, ELISA to test cAMP production, and spectrum method to test the melanin production. The results showed that compared to the normal melanocyte, the proliferation of melanocytes was increased within 60 h following adding IGF1. It also showed that cAMP content produced by melanocytes was increased, microphthalmia-associtated transcription factor (MITF), tyrosinase (TYR) and tyrosinase-related protein 2 (TYRP2) expression was increased, and melanin production with most obvious change in 10 ng/ml supplementary group, when compared with the control group. The results suggested that IGF1 with the dose of 10 ng/ml had the important effects on the melanogenesis in alpaca melanocyte by the cAMP pathway.

Effect of nicotine on melanogenesis and antioxidant status in HEMn-LP melanocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Delijewski, Marcin; Beberok, Artur; Otręba, Michał

Nicotine is a natural ingredient of tobacco plants and is responsible for the addictive properties of tobacco. Nowadays nicotine is also commonly used as a form of smoking cessation therapy. It is suggested that nicotine may be accumulated in human tissues containing melanin. This may in turn affect biochemical processes in human cells producing melanin. The aim of this study was to examine the effect of nicotine on melanogenesis and antioxidant status in cultured normal human melanocytes HEMn-LP. Nicotine induced concentration-dependent loss in melanocytes viability. The value of EC{sub 50} was determined to be 7.43 mM. Nicotine inhibited a melanizationmore » process in human light pigmented melanocytes and caused alterations of antioxidant defense system. Significant changes in cellular antioxidant enzymes: superoxide dismutase and catalase activities and in hydrogen peroxide content were stated. The obtained results may explain a potential influence of nicotine on biochemical processes in melanocytes in vivo during long term exposition to nicotine. - Graphical abstract: Nicotine inhibits melanogenesis and induces oxidative stress in HEMn-LP melanocytes. - Highlights: • Nicotine induces concentration-dependent loss in melanocytes viability. • Nicotine in non-cytotoxic concentrations inhibits melanogenesis. • Nicotine in higher concentrations induces oxidative stress.« less

Increased endogenous DNA oxidation correlates to increased iron levels in melanocytes relative to keratinocytes.

PubMed

Pelle, Edward; Huang, Xi; Zhang, Qi; Pernodet, Nadine; Yarosh, Daniel B; Frenkel, Krystyna

2014-01-01

The endogenous oxidative state of normal human epidermal melanocytes was investigated and compared to normal human epidermal keratinocytes (NHEKs) in order to gain new insight into melanocyte biology. Previously, we showed that NHEKs contain higher levels of hydrogen peroxide (H2O2) than melanocytes and that it can migrate from NHEKs to melanocytes by passive permeation. Nevertheless, despite lower concentrations of H2O2, we now report higher levels of oxidative DNA in melanocytes as indicated by increased levels of 8-oxo-2'-deoxyguanosine (8-oxo-dG): 4.49 (±0.55 SEM) 8-oxo-dG/10(6) dG compared to 1.49 (±0.11 SEM) 8-oxo-dG/10(6) dG for NHEKs. An antioxidant biomarker, glutathione (GSH), was also lower in melanocytes (3.14 nmoles (±0.15 SEM)/cell) in comparison to NHEKs (5.98 nmoles (±0.33 SEM)/cell). Intriguingly, cellular bioavailable iron as measured in ferritin was found to be nearly fourfold higher in melanocytes than in NHEKs. Further, ferritin levels in melanocytes were also higher than in hepatocarcinoma cells, an iron-rich cell, and it indicates that higher relative iron levels may be characteristic of melanocytes. To account for the increased oxidative DNA and lower GSH and H2O2 levels that we observe, we propose that iron may contribute to higher levels of oxidation by reacting with H2O2 through a Fenton reaction leading to the generation of DNA-reactive hydroxyl radicals. In conclusion, our data support the concept of elevated oxidation and high iron levels as normal parameters of melanocytic activity. We present new evidence that may contribute to our understanding of the melanogenic process and lead to the development of new skin care products.

Stem-Cell-Based Tumorigenesis in Adult Drosophila.

PubMed

Hou, S X; Singh, S R

2017-01-01

Recent studies suggest that a small subset of cells within a tumor, the so-called cancer stem cells (CSCs), are responsible for tumor propagation, relapse, and the eventual death of most cancer patients. CSCs may derive from a few tumor-initiating cells, which are either transformed normal stem cells or reprogrammed differentiated cells after acquiring initial cancer-causing mutations. CSCs and normal stem cells share some properties, but CSCs differ from normal stem cells in their tumorigenic ability. Notably, CSCs are usually resistant to chemo- and radiation therapies. Despite the apparent roles of CSCs in human cancers, the biology underlying their behaviors remains poorly understood. Over the past few years, studies in Drosophila have significantly contributed to this new frontier of cancer research. Here, we first review how stem-cell tumors are initiated and propagated in Drosophila, through niche appropriation in the posterior midgut and through stem-cell competition for niche occupancy in the testis. We then discuss the differences between normal and tumorigenic stem cells, revealed by studying Ras V12 -transformed stem-cell tumors in the Drosophila kidney. Finally, we review the biology behind therapy resistance, which has been elucidated through studies of stem-cell resistance and sensitivity to death inducers using female germline stem cells and intestinal stem cells of the posterior midgut. We expect that screens using adult Drosophila neoplastic stem-cell tumor models will be valuable for identifying novel and effective compounds for treating human cancers. © 2017 Elsevier Inc. All rights reserved.

Brain stem auditory evoked responses in human infants and adults

NASA Technical Reports Server (NTRS)

Hecox, K.; Galambos, R.

1974-01-01

Brain stem evoked potentials were recorded by conventional scalp electrodes in infants (3 weeks to 3 years of age) and adults. The latency of one of the major response components (wave V) is shown to be a function both of click intensity and the age of the subject; this latency at a given signal strength shortens postnatally to reach the adult value (about 6 msec) by 12 to 18 months of age. The demonstrated reliability and limited variability of these brain stem electrophysiological responses provide the basis for an optimistic estimate of their usefulness as an objective method for assessing hearing in infants and adults.

Adipose-derived adult stem cells: available technologies for potential clinical regenerative applications in dentistry.

PubMed

Catalano, Enrico; Cochis, Andrea; Varoni, Elena; Rimondini, Lia; Carrassi, Antonio; Azzimonti, Barbara

2013-01-01

Tissue homeostasis depends closely on the activity and welfare of adult stem cells. These cells represent a promising tool for biomedical research since they can aid in treatment and promote the regeneration of damaged organs in many human disorders. Adult stem cells indefinitely preserve their ability to self-renew and differentiate into various phenotypes; this capacity could be promoted in vitro by particular culture conditions (differentiation media) or spontaneously induced in vivo by exploiting the biochemical and mechanical properties of the tissue in which the stem cells are implanted. Among the different sources of adult stem cells, adipose tissue is an attractive possibility thanks to its ready availability and the standard extraction techniques at our disposal today. This review discusses the isolation, characterization, and differentiation of human adipose-derived adult stem cells, as well as regeneration strategies, therapeutic uses, and adverse effects of their delivery. In particular, since oral disorders (e.g., trauma, erosion, and chronic periodontitis) often cause the loss of dental tissue along with functional, phonetic, and aesthetic impairment, this review focuses on the application of human adipose-derived adult stem cells, alone or in combination with biomaterials, in treating oral diseases.

CDKN2B loss promotes progression from benign melanocytic nevus to melanoma

PubMed Central

McNeal, Andrew S.; Liu, Kevin; Nakhate, Vihang; Natale, Christopher A.; Duperret, Elizabeth K.; Capell, Brian C.; Dentchev, Tzvete; Berger, Shelley L.; Herlyn, Meenhard; Seykora, John T.; Ridky, Todd W.

2015-01-01

Deletion of the entire CDKN2B-CDKN2A gene cluster is among the most common genetic events in cancer. The tumor-promoting effects are generally attributed to loss of CDKN2A-encoded p16 and p14ARF tumor suppressors. The degree to which the associated CDKN2B-encoded p15 loss contributes to human tumorigenesis is unclear. Here we show that CDKN2B is highly upregulated in benign melanocytic nevi, contributes to maintaining nevus melanocytes in a growth-arrested premalignant state, and is commonly lost in melanoma. Using primary melanocytes isolated directly from freshly excised human nevi naturally expressing the common BRAF(V600E) activating mutation, nevi progressing to melanoma, and normal melanocytes engineered to inducibly express BRAF(V600E), we show that BRAF activation results in reversible, TGFβ-dependent, p15 induction that halts proliferation. Further, we engineer human skin grafts containing nevus-derived melanocytes to establish a new, architecturally faithful, in vivo melanoma model, and demonstrate that p15 loss promotes the transition from benign nevus to melanoma. PMID:26183406

FISH analysis for diagnostic evaluation of challenging melanocytic lesions.

PubMed

Zimmermann, A K; Hirschmann, A; Pfeiffer, D; Paredes, B E; Diebold, J

2010-09-01

The differential diagnosis of malignant melanomas and atypical melanocytic nevi is still a diagnostic challenge. The currently accepted morphologic criteria show substantial interobserver variability, likewise immunohistochemical studies are often not able to discriminate these lesions reliably. Techniques that support diagnostic accuracy are of the greatest importance considering the growing incidence of malignant melanomas and their increase in younger patients. In this study we analyzed the feasibility of fluorescence in situ hybridization (FISH) analysis for the discrimination of malignant and benign melanocytic tumors. A panel of DNA probes was used to detect chromosomal aberrations of chromosomes 6 and 11. On a series of 5 clearly malignant and benign melanocytic tumors we confirmed the applicability of the test. Then we focused on examination of ambiguous melanocytic lesions, where atypical cells are often difficult to relocalize in the 4',6-Diamidino-2-phenylindol (DAPI)-fluorescence stain. FISH analyses were conducted on destained H&E-stained slides. By comparison of the DAPI-image with photos taken from the H&E stain, unambiguous assignment of the FISH results to the conspicuous groups of cells was possible. The results of FISH analysis were consistent with the conventional diagnosis in 11 of 14 small ambiguous lesions. Of the remaining 3 cases, 2 showed FISH-results close to the cut-off level. Comparison of FISH results on thin and thick sections revealed that the cut-off values have to be adapted for 2 microm destained sections. In conclusion, FISH analysis is a useful and applicable tool for assessment of even smallest melanocytic neoplasms, although there will remain unclear cases that cannot be solved even after additional FISH evaluation.

PGE2 is a UVR-inducible autocrine factor for human melanocytes that stimulates tyrosinase activation

PubMed Central

Starner, Renny J.; McClelland, Lindy; Abdel-Malek, Zalfa; Fricke, Alex; Scott, Glynis

2013-01-01

Melanocyte proliferation, dendrite formation, and pigmentation are controlled by paracrine factors, particularly following exposure to ultraviolet radiation (UVR). Little is known about autocrine factors for melanocytes. Prostaglandins activate signaling pathways involved in growth, differentiation and apoptosis. Prostaglandin E2 (PGE2) is the most abundant prostaglandin released by keratinocytes following UVR, and stimulates the formation of dendrites in melanocytes. Synthesis of PGE2 is controlled by cPLA2, which releases arachidonic acid from membranes, and COX-2 and prostaglandin E2 synthases (PGES), which convert arachidonic acid to PGH2 and PGH2 to PGE2, respectively. In this report we show that multiple irradiations of human melanocytes with UVR stimulates tyrosinase activity, independent of expression of a functional melanocortin 1 receptor, suggesting the presence of a non-melanocortin autocrine factor. Irradiation of melanocytes activated cPLA2, the rate-limiting step in eicosanoid synthesis, and stimulated PGE2 secretion. PGE2 increased cAMP production, tyrosinase activity and proliferation in melanocytes. PGE2 binds to four distinct G-protein coupled receptors (EP1–4). We show that EP4 receptor signaling stimulates cAMP production in melanocytes. Conversely, stimulation of the EP3 receptor lowered basal cAMP levels. These data suggest that relative levels or activity of these receptors controls effects of PGE2 on cAMP in melanocytes. The data are the first to identify PGE2 as an UVR-inducible autocrine factor for melanocytes that stimulates tyrosinase activity and proliferation, and to show that EP3 and EP4 receptor signaling have opposing effects on cAMP production, a critical signaling pathway that regulates proliferation and melanogenesis in melanocytes. PMID:20500768

Association between melanocytic neoplasms and seborrheic keratosis: more than a coincidental collision?

PubMed Central

DeFazio, Jennifer; Zalaudek, Iris; Busam, Klaus J.; Cota, Carlo; Marghoob, Ashfaq

2012-01-01

Clinical observations and an expanding knowledge of cell-to-cell communication have led us to speculate that the finding of a melanocytic nevus in conjunction with a seborrheic keratosis is more than a coincidental collision of two lesions. Here we present five cases demonstrating dermoscopic features of both melanocytic lesions and seborrheic keratoses with corresponding histology. Four cases demonstrate dermoscopic features of a melanocytic nevus and seborrheic keratosis, and the final case a melanoma arising in association with a seborrheic keratosis. PMID:23785597

Tranexamic acid suppresses ultraviolet B eye irradiation-induced melanocyte activation by decreasing the levels of prohormone convertase 2 and alpha-melanocyte-stimulating hormone.

PubMed

Hiramoto, Keiichi; Yamate, Yurika; Sugiyama, Daijiro; Takahashi, Yumi; Mafune, Eiichi

2014-12-01

Tranexamic acid (trans-4-aminomethylcyclohexanecarboxylic acid) is a medicinal amino acid used in skin whitening care. This study examined the effects of tranexamic acid on the melanocyte activation of the skin induced by an ultraviolet (UV) B eye irradiation. The eye or ear was locally exposed to UVB at a dose of 1.0 kJ/m(2) using a 20SE sunlamp after covering the remaining body surface with aluminum foil. UVB eye irradiation induced melanocyte activation of the skin, similar to that observed following UVB ear irradiation, which was suppressed by the administration of tranexamic acid treatment. The plasma α-melanocyte-stimulating hormone (α-MSH) content was increased by UVB irradiation of the eye; however, the increase in α-MSH was suppressed by tranexamic acid treatment. In addition, UVB eye irradiation induced the up-regulation of prohormone convertase (PC) 2 in the pituitary gland. Meanwhile, the increase in PC2 induced by UVB eye irradiation was suppressed by tranexamic acid treatment. These results clearly indicate that tranexamic acid decreases the expression of PC2, which cleavages from proopiomelanocortin to α-MSH in the pituitary gland, thereby suppressing melanocyte activation. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Ablation of proliferating neural stem cells during early life is sufficient to reduce adult hippocampal neurogenesis.

PubMed

Youssef, Mary; Krish, Varsha S; Kirshenbaum, Greer S; Atsak, Piray; Lass, Tamara J; Lieberman, Sophie R; Leonardo, E David; Dranovsky, Alex

2018-05-09

Environmental exposures during early life, but not during adolescence or adulthood, lead to persistent reductions in neurogenesis in the adult hippocampal dentate gyrus (DG). The mechanisms by which early life exposures lead to long-term deficits in neurogenesis remain unclear. Here, we investigated whether targeted ablation of dividing neural stem cells during early life is sufficient to produce long-term decreases in DG neurogenesis. Having previously found that the stem cell lineage is resistant to long-term effects of transient ablation of dividing stem cells during adolescence or adulthood (Kirshenbaum et al., 2014), we used a similar pharmacogenetic approach to target dividing neural stem cells for elimination during early life periods sensitive to environmental insults. We then assessed the Nestin stem cell lineage in adulthood. We found that the adult neural stem cell reservoir was depleted following ablation during the first postnatal week, when stem cells were highly proliferative, but not during the third postnatal week, when stem cells were more quiescent. Remarkably, ablating proliferating stem cells during either the first or third postnatal week led to reduced adult neurogenesis out of proportion to the changes in the stem cell pool, indicating a disruption of the stem cell function or niche following stem cell ablation in early life. These results highlight the first three postnatal weeks as a series of sensitive periods during which elimination of dividing stem cells leads to lasting alterations in adult DG neurogenesis and stem cell function. These findings contribute to our understanding of the relationship between DG development and adult neurogenesis, as well as suggest a possible mechanism by which early life experiences may lead to lasting deficits in adult hippocampal neurogenesis. This article is protected by copyright. All rights reserved. © 2018 Wiley Periodicals, Inc.

Physiological Plasticity of Neural-Crest-Derived Stem Cells in the Adult Mammalian Carotid Body.

PubMed

Annese, Valentina; Navarro-Guerrero, Elena; Rodríguez-Prieto, Ismael; Pardal, Ricardo

2017-04-18

Adult stem cell plasticity, or the ability of somatic stem cells to cross boundaries and differentiate into unrelated cell types, has been a matter of debate in the last decade. Neural-crest-derived stem cells (NCSCs) display a remarkable plasticity during development. Whether adult populations of NCSCs retain this plasticity is largely unknown. Herein, we describe that neural-crest-derived adult carotid body stem cells (CBSCs) are able to undergo endothelial differentiation in addition to their reported role in neurogenesis, contributing to both neurogenic and angiogenic processes taking place in the organ during acclimatization to hypoxia. Moreover, CBSC conversion into vascular cell types is hypoxia inducible factor (HIF) dependent and sensitive to hypoxia-released vascular cytokines such as erythropoietin. Our data highlight a remarkable physiological plasticity in an adult population of tissue-specific stem cells and could have impact on the use of these cells for cell therapy. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Microphthalmia-associated transcription factor as the molecular target of cadmium toxicity in human melanocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chantarawong, Wipa; Inter Departmental Multidisciplinary Graduate Program in Bioscience, Faculty of Science, Kasetsart University, Bangkok; Takeda, Kazuhisa

Highlights: • In human melanocytes, cadmium decreases the expression of MITF-M and tyrosinase and their mRNAs. • In human melanoma cells, cadmium decreases the expression of MITF-M protein and tyrosinase mRNA. • Expression of MITF-H is less sensitive to cadmium toxicity in melanocyte-linage cells. • Cadmium does not decrease the expression of MITF-H in retinal pigment epithelial cells. • MITF-M is the molecular target of cadmium toxicity in melanocytes. - Abstract: Dietary intake of cadmium is inevitable, causing age-related increase in cadmium accumulation in many organs, including hair, choroid and retinal pigment epithelium (RPE). Cadmium has been implicated in themore » pathogenesis of hearing loss and macular degeneration. The functions of cochlea and retina are maintained by melanocytes and RPE, respectively, and the differentiation of these pigment cells is regulated by microphthalmia-associated transcription factor (MITF). In the present study, we explored the potential toxicity of cadmium in the cochlea and retina by using cultured human melanocytes and human RPE cell lines. MITF consists of multiple isoforms, including melanocyte-specific MITF-M and widely expressed MITF-H. Levels of MITF-M protein and its mRNA in human epidermal melanocytes and HMV-II melanoma cells were decreased significantly by cadmium. In parallel with the MITF reduction, mRNA levels of tyrosinase, the key enzyme of melanin biosynthesis that is regulated by MITF-M, were also decreased. In RPE cells, however, the levels of total MITF protein, constituting mainly MITF-H, were not decreased by cadmium. We thus identify MITF-M as the molecular target of cadmium toxicity in melanocytes, thereby accounting for the increased risk of disability from melanocyte malfunction, such as hearing and vision loss among people with elevated cadmium exposure.« less

Conjunctival melanocytic tumors in children - a challenge in diagnosis and treatment.

PubMed

Ciuntu, Roxana Elena; Martinescu, Gabriel; Anton, Nicoleta; Danciu, Mihai

2018-01-01

Conjunctival melanocytic lesions are very diverse pigmented tumors that include benign, premalignant and malignant tumors. The aim of this article is to highlight the clinical and histopathological aspects of conjunctival melanocytic tumors at children. This study is a retrospective case series study of three patients selected from fifteen cases with melanocytic conjunctival tumors who were operated in the Department of Ophthalmology, "St. Spiridon" Emergency Hospital, Iasi, Romania. A systematic review of the literature was undertaken, using an electronic search of PubMed/MEDLINE, Google Scholar and ISI Web of Knowledge, to identify original English or French articles and reviews on this subject. Patients were diagnosed by the same doctor between 2004 and 2016, in ambulatory of Department of Ophthalmology of the same Hospital. The age of patients was between 7 and 17 years old. Three cases (boys) were treated by surgery - one patient with conjunctival malignant melanoma (histologically confirmed) derived from a pre-existing benign conjunctival nevus (diagnosed 1.5 years before), a patient was operated for aesthetic reasons (with histological diagnosis of compound conjunctival melanocytic nevus) and one boy was diagnosed of melanocytic conjunctival nevus. All cases operated had normal visual acuity and fundoscopy. There was no regional lymph node present in any case studied. The traditional method for clinical diagnosis of suspected pigmented conjunctival lesions was to remove these lesions surgically and to examine architectural and cytological features with light microscopy. We recommend an immunohistochemical staining for the detection of specific cellular antigens in conjunctival melanocytic tumors in children. The diagnosis, treatment and the follow-up of the patient were challenges for the ophthalmologist.

Pluripotency of adult stem cells derived from human and rat pancreas

NASA Astrophysics Data System (ADS)

Kruse, C.; Birth, M.; Rohwedel, J.; Assmuth, K.; Goepel, A.; Wedel, T.

Adult stem cells are undifferentiated cells found within fully developed tissues or organs of an adult individuum. Until recently, these cells have been considered to bear less self-renewal ability and differentiation potency compared to embryonic stem cells. In recent studies an undifferentiated cell type was found in primary cultures of isolated acini from exocrine pancreas termed pancreatic stellate cells. Here we show that pancreatic stellate-like cells have the capacity of extended self-renewal and are able to differentiate spontaneously into cell types of all three germ layers expressing markers for smooth muscle cells, neurons, glial cells, epithelial cells, chondrocytes and secretory cells (insulin, amylase). Differentiation and subsequent formation of three-dimensional cellular aggregates (organoid bodies) were induced by merely culturing pancreatic stellate-like cells in hanging drops. These cells were developed into stable, long-term, in vitro cultures of both primary undifferentiated cell lines as well as organoid cultures. Thus, evidence is given that cell lineages of endodermal, mesodermal, and ectodermal origin arise spontaneously from a single adult undifferentiated cell type. Based on the present findings it is assumed that pancreatic stellate-like cells are a new class of lineage uncommitted pluripotent adult stem cells with a remarkable self-renewal ability and differentiation potency. The data emphasize the versatility of adult stem cells and may lead to a reappraisal of their use for the treatment of inherited disorders or acquired degenerative diseases.

Aberrant expression of HMB-45 in traumatized melanocytic nevi.

PubMed

Leleux, Todd M; Prieto, Victor G; Diwan, A Hafeez

2012-09-01

Assessment of histologic and immunohistochemical maturation (with HMB-45 and anti-Ki-67) may be helpful in differentiating benign melanocytic nevi (BMN) from malignant melanoma. Recently, we reported loss of maturation and aberrant immunohistochemical findings in melanocytic nevi after liquid nitrogen cryotherapy (Adeniran et al, J Am Acad Dermatol 2009;61:341-5). Herein we report a similar phenomenon identified in traumatized melanocytic nevi (TMN). We sought to evaluate the histologic and immunohistochemical findings in early and late stages of traumatized nevi. Twenty-four cases of TMN were retrieved from the pathology archives. These were then assessed by two pathologists (T.L. and A.H.D.) using HMB-45 and MIB-1 (for Ki-67) antibodies. TMN showed some of the following findings: epidermal changes (parakeratosis, ulceration, serum crust, flattening of the epidermis) and dermal changes including fibrosis and the presence of melanophages. In some cases, there was architectural disorder of the overlying melanocytes, with crowding in the basal layer, but without significant pagetoid spread. Occasionally, the dermal scar contained larger, more epithelioid-appearing melanocytes than those beneath the scar. Fifty-four percent of TMN lacked obvious immunohistochemical maturation with HMB-45, since nevus cells within the scar or directly beneath it were strongly labeled. None of the TMN showed appreciable labeling for Ki-67. The exact clinical duration between trauma and biopsy could not be determined. Loss of maturation with HMB-45 in TMN can be a diagnostic pitfall in challenging cases. Concurrent evaluation of MIB-1 expression, along with the characteristic histologic features of trauma, should allow the correct diagnosis to be reached. Copyright © 2011 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.

Thyroid hormone regulation of adult intestinal stem cells: Implications on intestinal development and homeostasis.

PubMed

Sun, Guihong; Roediger, Julia; Shi, Yun-Bo

2016-12-01

Organ-specific adult stem cells are essential for organ homeostasis, tissue repair and regeneration. The formation of such stem cells often takes place during postembryonic development, a period around birth in mammals when plasma thyroid hormone concentration is high. The life-long self-renewal of the intestinal epithelium has made mammalian intestine a valuable model to study the function and regulation and adult stem cells. On the other hand, much less is known about how the adult intestinal stem cells are formed during vertebrate development. Here, we will review some recent progresses on this subject, focusing mainly on the formation of the adult intestine during Xenopus metamorphosis. We will discuss the role of thyroid hormone signaling pathway in the process and potential molecular conservations between amphibians and mammals as well as the implications in organ homeostasis and human diseases.

Dll1 maintains quiescence of adult neural stem cells and segregates asymmetrically during mitosis.

PubMed

Kawaguchi, Daichi; Furutachi, Shohei; Kawai, Hiroki; Hozumi, Katsuto; Gotoh, Yukiko

2013-01-01

Stem cells often divide asymmetrically to produce one stem cell and one differentiating cell, thus maintaining the stem cell pool. Although neural stem cells (NSCs) in the adult mouse subventricular zone have been suggested to divide asymmetrically, intrinsic cell fate determinants for asymmetric NSC division are largely unknown. Stem cell niches are important for stem cell maintenance, but the niche for the maintenance of adult quiescent NSCs has remained obscure. Here we show that the Notch ligand Delta-like 1 (Dll1) is required to maintain quiescent NSCs in the adult mouse subventricular zone. Dll1 protein is induced in activated NSCs and segregates to one daughter cell during mitosis. Dll1-expressing cells reside in close proximity to quiescent NSCs, suggesting a feedback signal for NSC maintenance by their sister cells and progeny. Our data suggest a model in which NSCs produce their own niche cells for their maintenance through asymmetric Dll1 inheritance at mitosis.

Dll1 maintains quiescence of adult neural stem cells and segregates asymmetrically during mitosis

PubMed Central

Kawaguchi, Daichi; Furutachi, Shohei; Kawai, Hiroki; Hozumi, Katsuto; Gotoh, Yukiko

2013-01-01

Stem cells often divide asymmetrically to produce one stem cell and one differentiating cell, thus maintaining the stem cell pool. Although neural stem cells (NSCs) in the adult mouse subventricular zone have been suggested to divide asymmetrically, intrinsic cell fate determinants for asymmetric NSC division are largely unknown. Stem cell niches are important for stem cell maintenance, but the niche for the maintenance of adult quiescent NSCs has remained obscure. Here we show that the Notch ligand Delta-like 1 (Dll1) is required to maintain quiescent NSCs in the adult mouse subventricular zone. Dll1 protein is induced in activated NSCs and segregates to one daughter cell during mitosis. Dll1-expressing cells reside in close proximity to quiescent NSCs, suggesting a feedback signal for NSC maintenance by their sister cells and progeny. Our data suggest a model in which NSCs produce their own niche cells for their maintenance through asymmetric Dll1 inheritance at mitosis. PMID:23695674

Melanoma Arising in a Melanocytic Nevus.

PubMed

Martín-Gorgojo, A; Nagore, E

2018-03-01

The association of melanoma with a preexisting melanocytic nevus varies considerably between series, depending on whether the association is based on histological signs (4%-72%) or a clinically evident lesion (42%-85%). Histological association with a nevus correlates with favorable prognostic factors, whereas a clinical association correlates with unfavorable factors. In this review, we discuss the characteristics of nevus-associated melanoma from different perspectives: Whiteman's divergent pathway hypothesis for the development of cutaneous melanoma; and the factors involved in nevogenicity, including both the genetic and molecular factors involved in the development of the melanoma and its precursor lesions. Finally, a cumulative analysis of the 16 162 cases reported in the literature revealed that 29.8% of melanomas are histologically associated with a melanocytic nevus. Copyright © 2017 AEDV. Publicado por Elsevier España, S.L.U. All rights reserved.

Pleiotrophin inhibits melanogenesis via Erk1/2-MITF signaling in normal human melanocytes.

PubMed

Choi, Woo Jong; Kim, Misun; Park, Ji-Youn; Park, Tae Jun; Kang, Hee Young

2015-01-01

Pleiotrophin (PTN) is a secreted heparin-binding protein that is involved in various biological functions of cell growth and differentiation. Little is known about the effects of PTN on the melanocyte function and skin pigmentation. In this study, we investigated whether PTN would affect melanogenesis. PTN was expressed in melanocytes and fibroblasts of human skin. Transfection studies revealed that PTN decreased melanogenesis, probably through MITF degradation via Erk1/2 activation in melanocytes. The inhibitory action of PTN in pigmentation was further confirmed in ex vivo cultured skin and in the melanocytes cocultured with fibroblasts. These findings suggest that PTN is a crucial factor for the regulation of melanogenesis in the skin. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Adult stem cell-based apexogenesis

PubMed Central

Li, Yao; Shu, Li-Hong; Yan, Ming; Dai, Wen-Yong; Li, Jun-Jun; Zhang, Guang-Dong; Yu, Jin-Hua

2014-01-01

Generally, the dental pulp needs to be removed when it is infected, and root canal therapy (RCT) is usually required in which infected dental pulp is replaced with inorganic materials (paste and gutta percha). This treatment approach ultimately brings about a dead tooth. However, pulp vitality is extremely important to the tooth itself, since it provides nutrition and acts as a biosensor to detect the potential pathogenic stimuli. Despite the reported clinical success rate, RCT-treated teeth are destined to be devitalized, brittle and susceptible to postoperative fracture. Recently, the advances and achievements in the field of stem cell biology and regenerative medicine have inspired novel biological approaches to apexogenesis in young patients suffering from pulpitis or periapical periodontitis. This review mainly focuses on the benchtop and clinical regeneration of root apex mediated by adult stem cells. Moreover, current strategies for infected pulp therapy are also discussed here. PMID:25332909

Oncogenic mutations in melanomas and benign melanocytic nevi of the female genital tract

PubMed Central

Tseng, Diane; Kim, Julie; Warrick, Andrea; Nelson, Dylan; Pukay, Marina; Beadling, Carol; Heinrich, Michael; Selim, Maria Angelica; Corless, Christopher L.; Nelson, Kelly

2015-01-01

Background The genetic heterogeneity of melanomas and melanocytic nevi of the female genital tract is poorly understood. Objective We aim to characterize the frequency of mutations of the following genes: BRAF, NRAS, KIT, GNA11, and GNAQ in female genital tract melanomas. We also characterize the frequency of BRAF mutations in female genital tract melanomas compared with melanocytic nevi. Methods Mutational screening was performed on the following female genital tract melanocytic neoplasms: 25 melanomas, 7 benign melanocytic nevi, and 4 atypical melanocytic nevi. Results Of the 25 female genital tract melanoma specimens queried, KIT mutations were detected in 4 (16.0%), NRAS mutations in 4 (16.0%), and BRAF mutations in 2 (8.0%) samples. Two of the tumors with KIT mutations harbored double mutations in the same exon. No GNAQ or GNA11 mutations were identified among 11 melanomas screened. BRAF V600E mutations were detected in 7 of 7 benign melanocytic genital nevi (100%) and 3 of 4 atypical genital nevi (75%). Limitations Our study is limited by the small sample size of this rare subset of melanomas. Conclusion KIT, NRAS, and BRAF mutations are found in a subset of female genital tract melanomas. Screening for oncogenic mutations is important for developing and applying clinical therapies for melanomas of the female genital tract. PMID:24842760

Oncogenic mutations in melanomas and benign melanocytic nevi of the female genital tract.

PubMed

Tseng, Diane; Kim, Julie; Warrick, Andrea; Nelson, Dylan; Pukay, Marina; Beadling, Carol; Heinrich, Michael; Selim, Maria Angelica; Corless, Christopher L; Nelson, Kelly

2014-08-01

The genetic heterogeneity of melanomas and melanocytic nevi of the female genital tract is poorly understood. We aim to characterize the frequency of mutations of the following genes: BRAF, NRAS, KIT, GNA11, and GNAQ in female genital tract melanomas. We also characterize the frequency of BRAF mutations in female genital tract melanomas compared with melanocytic nevi. Mutational screening was performed on the following female genital tract melanocytic neoplasms: 25 melanomas, 7 benign melanocytic nevi, and 4 atypical melanocytic nevi. Of the 25 female genital tract melanoma specimens queried, KIT mutations were detected in 4 (16.0%), NRAS mutations in 4 (16.0%), and BRAF mutations in 2 (8.0%) samples. Two of the tumors with KIT mutations harbored double mutations in the same exon. No GNAQ or GNA11 mutations were identified among 11 melanomas screened. BRAF V600E mutations were detected in 7 of 7 benign melanocytic genital nevi (100%) and 3 of 4 atypical genital nevi (75%). Our study is limited by the small sample size of this rare subset of melanomas. KIT, NRAS, and BRAF mutations are found in a subset of female genital tract melanomas. Screening for oncogenic mutations is important for developing and applying clinical therapies for melanomas of the female genital tract. Copyright © 2014 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.

Adult human neural stem cell therapeutics: Current developmental status and prospect.

PubMed

Nam, Hyun; Lee, Kee-Hang; Nam, Do-Hyun; Joo, Kyeung Min

2015-01-26

Over the past two decades, regenerative therapies using stem cell technologies have been developed for various neurological diseases. Although stem cell therapy is an attractive option to reverse neural tissue damage and to recover neurological deficits, it is still under development so as not to show significant treatment effects in clinical settings. In this review, we discuss the scientific and clinical basics of adult neural stem cells (aNSCs), and their current developmental status as cell therapeutics for neurological disease. Compared with other types of stem cells, aNSCs have clinical advantages, such as limited proliferation, inborn differentiation potential into functional neural cells, and no ethical issues. In spite of the merits of aNSCs, difficulties in the isolation from the normal brain, and in the in vitro expansion, have blocked preclinical and clinical study using aNSCs. However, several groups have recently developed novel techniques to isolate and expand aNSCs from normal adult brains, and showed successful applications of aNSCs to neurological diseases. With new technologies for aNSCs and their clinical strengths, previous hurdles in stem cell therapies for neurological diseases could be overcome, to realize clinically efficacious regenerative stem cell therapeutics.

Adult pituitary stem cells: from pituitary plasticity to adenoma development.

PubMed

Florio, Tullio

2011-01-01

The pituitary needs high plasticity of the hormone-producing cell compartment to generate the continuously changing hormonal signals that govern the key physiological processes it is involved in, as well as homeostatic cell turnover. However, the underlying mechanisms are still poorly understood. It was proposed that adult stem cells direct the generation of newborn cells with a hormonal phenotype according to the physiological requirements. However, only in recent years adult pituitary stem cells have begun to be phenotypically characterized in several studies that identified multiple stem/progenitor cell candidates. Also considering the incompletely defined features of this cell subpopulation, some discrepancies among the different reports are clearly apparent and long-term self-renewal remains to be unequivocally demonstrated. Here, all the recently published evidence is analyzed, trying, when possible, to reconcile the results of the different studies. Finally, with the perspective of shedding light on pituitary tumorigenesis and the development of potentially new pharmacological approaches directed against these cells, very recent evidence on the presence of putative cancer stem cells in human pituitary adenomas is discussed. Copyright © 2011 S. Karger AG, Basel.

The potential role of adult stem cells in the management of the rheumatic diseases

PubMed Central

Franceschetti, Tiziana; De Bari, Cosimo

2017-01-01

Adult stem cells are considered as appealing therapeutic candidates for inflammatory and degenerative musculoskeletal diseases. A large body of preclinical research has contributed to describing their immune-modulating properties and regenerative potential. Additionally, increasing evidence suggests that stem cell differentiation and function are disrupted in the pathogenesis of rheumatic diseases. Clinical studies have been limited, for the most part, to the application of adult stem cell-based treatments on small numbers of patients or as a ‘salvage’ therapy in life-threatening disease cases. Nevertheless, these preliminary studies indicate that adult stem cells are promising tools for the long-term treatment of rheumatic diseases. This review highlights recent knowledge acquired in the fields of hematopoietic and mesenchymal stem cell therapy for the management of systemic sclerosis (SSc), systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and osteoarthritis (OA) and the potential mechanisms mediating their function. PMID:28717403

Expression of cytosolic NADP(+)-dependent isocitrate dehydrogenase in melanocytes and its role as an antioxidant.

PubMed

Kim, Ji Young; Shin, Jae Yong; Kim, Miri; Hann, Seung-Kyung; Oh, Sang Ho

2012-02-01

Cytosolic NADP(+)-dependent ICDH (IDPc) has an antioxidant effect as a supplier of NADPH to the cytosol, which is needed for the production of glutathione. To evaluate the expression of IDPc in melanocytes and to elucidate its role as an antioxidant. The knock-down of IDPc expression in immortalized mouse melanocyte cell lines (melan-a) was performed using the short interfering RNA (siRNA)-targeted gene silencing method. After confirming the silencing of IDPc expression with mRNA and protein levels, viability, apoptosis and necrosis, as well as ROS production in IDPc-silenced melanocytes were monitored under conditions of oxidative stress and non-stress. Also, the ratio of oxidized glutathione to total glutathione was examined, and whether the addition of glutathione recovered cell viability, decreased by oxidant stress, was checked. The expression of IDPc in both primary human melanocytes and melan-a cells was confirmed by Western blot and RT-PCR. The silencing of IDPc expression by transfecting IDPc siRNA in melan-a cells was observed by Western blotting and real-time RT-PCR. IDPc knock-down cells showed significantly decreased cell viability and an increased number of cells under apoptosis and necrosis. IDPc siRNA-treated melanocytes demonstrated a higher intensity of DCFDA after the addition of H(2)O(2) compared with scrambled siRNA-treated melanocytes, and a lower ratio of reduced glutathione to oxidized glutathione were observed in IDPc siRNA transfected melanocytes. In addition, the addition of glutathione recovered cell viability, which was previously decreased after incubation with H(2)O(2). This study suggests that decreased IDPc expression renders melanocytes more vulnerable to oxidative stress, and IDPc plays an important antioxidant function in melanocytes. Copyright © 2011 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

Optimal management of common acquired melanocytic nevi (moles): current perspectives

PubMed Central

Sardana, Kabir; Chakravarty, Payal; Goel, Khushbu

2014-01-01

Although common acquired melanocytic nevi are largely benign, they are probably one of the most common indications for cosmetic surgery encountered by dermatologists. With recent advances, noninvasive tools can largely determine the potential for malignancy, although they cannot supplant histology. Although surgical shave excision with its myriad modifications has been in vogue for decades, the lack of an adequate histological sample, the largely blind nature of the procedure, and the possibility of recurrence are persisting issues. Pigment-specific lasers were initially used in the Q-switched mode, which was based on the thermal relaxation time of the melanocyte (size 7 μm; 1 μsec), which is not the primary target in melanocytic nevus. The cluster of nevus cells (100 μm) probably lends itself to treatment with a millisecond laser rather than a nanosecond laser. Thus, normal mode pigment-specific lasers and pulsed ablative lasers (CO2/erbium [Er]:yttrium aluminum garnet [YAG]) are more suited to treat acquired melanocytic nevi. The complexities of treating this disorder can be overcome by following a structured approach by using lasers that achieve the appropriate depth to treat the three subtypes of nevi: junctional, compound, and dermal. Thus, junctional nevi respond to Q-switched/normal mode pigment lasers, where for the compound and dermal nevi, pulsed ablative laser (CO2/Er:YAG) may be needed. If surgical excision is employed, a wide margin and proper depth must be ensured, which is skill dependent. A lifelong follow-up for recurrence and melanoma is warranted in predisposed individuals, although melanoma is decidedly uncommon in most acquired melanocytic nevi, even though histological markers may be seen on evaluation. PMID:24672253

Automated Estimation of Melanocytic Skin Tumor Thickness by Ultrasonic Radiofrequency Data.

PubMed

Andrekute, Kristina; Valiukeviciene, Skaidra; Raisutis, Renaldas; Linkeviciute, Gintare; Makstiene, Jurgita; Kliunkiene, Renata

2016-05-01

High-frequency (>20-MHz) ultrasound (US) is a noninvasive preoperative tool for assessment of melanocytic skin tumor thickness. Ultrasonic melanocytic skin tumor thickness estimation is not always easy and is related to the experience of the clinician. In this article, we present an automated thickness measurement method based on time-frequency analysis of US radiofrequency signals. The study was performed on 52 thin (≤1-mm) melanocytic skin tumors (46 melanocytic nevi and 6 melanomas). Radiofrequency signals were obtained with a single-element focused transducer (fundamental frequency, 22 MHz; bandwidth, 12-28 MHz). The radiofrequency data were analyzed in the time-frequency domain to make the tumor boundaries more noticeable. The thicknesses of the tumors were evaluated by 3 different metrics: histologically measured Breslow thickness, manually measured US thickness, and automatically measured US thickness. The results showed a higher correlation coefficient between the automatically measured US thickness and Breslow thickness (r= 0.83; P< .0001) than the manually measured US thickness (r = 0.68; P < .0001). The sensitivity of the automated tumor thickness measurement algorithm was 96.55%, and the specificity was 78.26% compared with histologic measurement. The sensitivity of the manually measured US thickness was 75.86%, and the specificity was 73.91%. The efficient automated tumor thickness measurement method developed could be used as a tool for preoperative assessment of melanocytic skin tumor thickness. © 2016 by the American Institute of Ultrasound in Medicine.

Glutathione maintenance is crucial for survival of melanocytes after exposure to rhododendrol.

PubMed

Kondo, Masatoshi; Kawabata, Keigo; Sato, Kohji; Yamaguchi, Sayuri; Hachiya, Akira; Takahashi, Yoshito; Inoue, Shintaro

2016-09-01

Rhododendrol is a phenolic compound that shows a tyrosinase-dependent toxicity for melanocytes and occasionally induces a vitiligo-like skin depigmentation. The post-tyrosinase mechanisms determining melanocyte death or survival, however, are far from clear. Here, we find that rhododendrol treatment leads to a reduction in the levels of cellular glutathione but also induces a cellular antioxidant response that eventually increases glutathione levels. We further find that rhododendrol toxicity is enhanced when glutathione levels are experimentally reduced and alleviated when glutathione levels are increased. Hence, it appears that the size of the preexisting glutathione pool along with the capacity to supply glutathione via the antioxidant response determines whether melanocytes survive or die after rhododendrol exposure. It is conceivable, therefore, that rhododendrol-induced leukoderma depends on the capacity to maintain appropriate glutathione levels and that enhancement of glutathione levels may preserve a patient's melanocytes and potentially help in repigmentation. © 2016 The Authors. Pigment Cell & Melanoma Research published by John Wiley & Sons Ltd.

Oxidative stress-induced overexpression of miR-25: the mechanism underlying the degeneration of melanocytes in vitiligo

PubMed Central

Shi, Q; Zhang, W; Guo, S; Jian, Z; Li, S; Li, K; Ge, R; Dai, W; Wang, G; Gao, T; Li, C

2016-01-01

Oxidative stress has a critical role in the pathogenesis of vitiligo. However, the specific molecular mechanism involved in oxidative stress-induced melanocyte death is not well characterized. Given the powerful role of microRNAs (miRNAs) in the regulation of cell survival as well as the fact that the generation of miRNAs can be affected by oxidative stress, we hypothesized that miRNAs may participate in vitiligo pathogenesis by modulating the expression of vital genes in melanocytes. In the present study, we initially found that miR-25 was increased in both serum and lesion samples from vitiligo patients, and its serum level was correlated with the activity of vitiligo. Moreover, restoration of miR-25 promoted the H2O2-induced melanocyte destruction and led to the dysfunction of melanocytes. Further experiments proved that MITF, a master regulator in melanocyte survival and function, accounted for the miR-25-caused damaging impact on melanocytes. Notably, other than the direct role on melanocytes, we observed that miR-25 inhibited the production and secretion of SCF and bFGF from keratinocytes, thus impairing their paracrine protective effect on the survival of melanocytes under oxidative stress. At last, we verified that oxidative stress could induce the overexpression of miR-25 in both melanocytes and keratinocytes possibly by demethylating the promoter region of miR-25. Taken together, our study demonstrates that oxidative stress-induced overexpression of miR-25 in vitiligo has a crucial role in promoting the degeneration of melanocytes by not only suppressing MITF in melanocytes but also impairing the paracrine protective effect of keratinocytes. Therefore, it is worthy to investigate the possibility of miR-25 as a potential drug target for anti-oxidative therapy in vitiligo. PMID:26315342

Conversion of adult endothelium to immunocompetent haematopoietic stem cells.

PubMed

Lis, Raphael; Karrasch, Charles C; Poulos, Michael G; Kunar, Balvir; Redmond, David; Duran, Jose G Barcia; Badwe, Chaitanya R; Schachterle, William; Ginsberg, Michael; Xiang, Jenny; Tabrizi, Arash Rafii; Shido, Koji; Rosenwaks, Zev; Elemento, Olivier; Speck, Nancy A; Butler, Jason M; Scandura, Joseph M; Rafii, Shahin

2017-05-25

Developmental pathways that orchestrate the fleeting transition of endothelial cells into haematopoietic stem cells remain undefined. Here we demonstrate a tractable approach for fully reprogramming adult mouse endothelial cells to haematopoietic stem cells (rEC-HSCs) through transient expression of the transcription-factor-encoding genes Fosb, Gfi1, Runx1, and Spi1 (collectively denoted hereafter as FGRS) and vascular-niche-derived angiocrine factors. The induction phase (days 0-8) of conversion is initiated by expression of FGRS in mature endothelial cells, which results in endogenous Runx1 expression. During the specification phase (days 8-20), RUNX1 + FGRS-transduced endothelial cells commit to a haematopoietic fate, yielding rEC-HSCs that no longer require FGRS expression. The vascular niche drives a robust self-renewal and expansion phase of rEC-HSCs (days 20-28). rEC-HSCs have a transcriptome and long-term self-renewal capacity similar to those of adult haematopoietic stem cells, and can be used for clonal engraftment and serial primary and secondary multi-lineage reconstitution, including antigen-dependent adaptive immune function. Inhibition of TGFβ and CXCR7 or activation of BMP and CXCR4 signalling enhanced generation of rEC-HSCs. Pluripotency-independent conversion of endothelial cells into autologous authentic engraftable haematopoietic stem cells could aid treatment of haematological disorders.

Expression and function of orphan nuclear receptor TLX in adult neural stem cells.

PubMed

Shi, Yanhong; Chichung Lie, D; Taupin, Philippe; Nakashima, Kinichi; Ray, Jasodhara; Yu, Ruth T; Gage, Fred H; Evans, Ronald M

2004-01-01

The finding of neurogenesis in the adult brain led to the discovery of adult neural stem cells. TLX was initially identified as an orphan nuclear receptor expressed in vertebrate forebrains and is highly expressed in the adult brain. The brains of TLX-null mice have been reported to have no obvious defects during embryogenesis; however, mature mice suffer from retinopathies, severe limbic defects, aggressiveness, reduced copulation and progressively violent behaviour. Here we show that TLX maintains adult neural stem cells in an undifferentiated, proliferative state. We show that TLX-expressing cells isolated by fluorescence-activated cell sorting (FACS) from adult brains can proliferate, self-renew and differentiate into all neural cell types in vitro. By contrast, TLX-null cells isolated from adult mutant brains fail to proliferate. Reintroducing TLX into FACS-sorted TLX-null cells rescues their ability to proliferate and to self-renew. In vivo, TLX mutant mice show a loss of cell proliferation and reduced labelling of nestin in neurogenic areas in the adult brain. TLX can silence glia-specific expression of the astrocyte marker GFAP in neural stem cells, suggesting that transcriptional repression may be crucial in maintaining the undifferentiated state of these cells.

FDA regulation of adult stem cell therapies as used in sports medicine.

PubMed

Chirba, Mary Ann; Sweetapple, Berkley; Hannon, Charles P; Anderson, John A

2015-02-01

In sports medicine, adult stem cells are the subject of great interest. Several uses of stem cells are under investigation including cartilage repair, meniscal regeneration, anterior cruciate ligament reconstruction, and tendinopathy. Extensive clinical and basic science research is warranted as stem cell therapies become increasingly common in clinical practice. In the United States, the Food and Drug Administration (FDA) is responsible for regulating the use of stem cells through its "Human Cells, Tissues, and Cellular and Tissue-Based Products" regulations. This report provides a brief overview of FDA regulation of adult stem cells. Several common clinical case scenarios are then presented that highlight how stem cells are currently being used in sports medicine and how current FDA regulations are likely to affect the physicians who use them. In the process, it explains how a variety of factors in sourcing and handling these cells, particularly the extent of cell manipulation, will affect what a physician can and cannot do without first obtaining the FDA's express approval. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Differential responses of choroidal melanocytes and uveal melanoma cells to low oxygen conditions

PubMed Central

Weidmann, Cindy; Pomerleau, Jade; Trudel-Vandal, Laurence

2017-01-01

Purpose Tissue culture is traditionally performed at atmospheric oxygen concentration (21%), which induces hyperoxic stress, as endogenous physiologic oxygen tension found in tissues varies between 2% and 9%. This discrepancy may lead to misinterpretation of results and may explain why effects observed in vitro cannot always be reproduced in vivo and vice versa. Only a few studies have been conducted in low physiologic oxygen conditions to understand the development and differentiation of cells from the eye. Methods The aim of this study was to investigate the growth and gene expression profile of melanocytes from the choroid permanently exposed to 21% (hyperoxic) or 3% (physiologic) oxygen with proliferation assays and DNA microarray. The cellular behavior of the melanocytes was then compared to that of cancer cells. Results The gross morphology and melanin content of choroidal melanocytes changed slightly when they were exposed to 3% O2, and the doubling time was statistically significantly faster. There was an increase in the percentage of choroidal melanocytes in the active phases of the cell cycle as observed by using the proliferation marker Ki67. The caveolin-1 senescence marker was not increased in choroidal melanocytes or uveal melanoma cells grown in hyperoxia. In comparison, the morphology of the uveal melanoma cells was similar between the two oxygen levels, and the doubling time was slower at 3% O2. Surprisingly, gene expression profiling of the choroidal melanocytes did not reveal a large list of transcripts considerably dysregulated between the two oxygen concentrations; only the lactate transporter monocarboxylate transporter (MCT4) was statistically significantly upregulated at 3% O2. Conclusions This study showed that the oxygen concentration must be tightly controlled in experimental settings, because it influences the subsequent cellular behavior of human choroidal melanocytes. PMID:28356703

Collision Tumor between Trichofolliculoma and Melanocytic Nevus.

PubMed

Bolte, Christel; Cullen, Roberto; Sazunic, Ivo

2017-01-01

Trichofolliculoma (TF) is a hamartomatous hair follicle-related tumor, clinically described as a dome-shaped papule with a central pore crossed by one or more silky white hairs. Histologically, it described as a cystic cavity containing keratinous debris, hair shaft fragments, and numerous hair follicles arising from its linings. Collision or compound tumors are a coexistence of two or more identifiable tumors in the same lesion. We present a case of a 47-year-old man with a lesion on his left cheek clinically characterized as a TF. However, the histopathological study reveals a collision tumor involving a TF and a melanocytic nevus. Collision tumors involving melanocytic nevi and hair follicle-related tumors have been previously reported, such as desmoplastic trichoepithelioma, epidermoid cyst, folliculosebaceous cystic hamartoma, and trichoadenoma.

Adult mesenchymal stem cells and cell-based tissue engineering

PubMed Central

Tuan, Rocky S; Boland, Genevieve; Tuli, Richard

2003-01-01

The identification of multipotential mesenchymal stem cells (MSCs) derived from adult human tissues, including bone marrow stroma and a number of connective tissues, has provided exciting prospects for cell-based tissue engineering and regeneration. This review focuses on the biology of MSCs, including their differentiation potentials in vitro and in vivo, and the application of MSCs in tissue engineering. Our current understanding of MSCs lags behind that of other stem cell types, such as hematopoietic stem cells. Future research should aim to define the cellular and molecular fingerprints of MSCs and elucidate their endogenous role(s) in normal and abnormal tissue functions. PMID:12716446

The Chromatin Remodeler BPTF Activates a Stemness Gene-Expression Program Essential for the Maintenance of Adult Hematopoietic Stem Cells.

PubMed

Xu, Bowen; Cai, Ling; Butler, Jason M; Chen, Dongliang; Lu, Xiongdong; Allison, David F; Lu, Rui; Rafii, Shahin; Parker, Joel S; Zheng, Deyou; Wang, Gang Greg

2018-03-13

Self-renewal and differentiation of adult stem cells are tightly regulated partly through configuration of chromatin structure by chromatin remodelers. Using knockout mice, we here demonstrate that bromodomain PHD finger transcription factor (BPTF), a component of the nucleosome remodeling factor (NURF) chromatin-remodeling complex, is essential for maintaining the population size of hematopoietic stem/progenitor cells (HSPCs), including long-term hematopoietic stem cells (HSCs). Bptf-deficient HSCs are defective in reconstituted hematopoiesis, and hematopoietic-specific knockout of Bptf caused profound defects including bone marrow failure and anemia. Genome-wide transcriptome profiling revealed that BPTF loss caused downregulation of HSC-specific gene-expression programs, which contain several master transcription factors (Meis1, Pbx1, Mn1, and Lmo2) required for HSC maintenance and self-renewal. Furthermore, we show that BPTF potentiates the chromatin accessibility of key HSC "stemness" genes. These results demonstrate an essential requirement of the chromatin remodeler BPTF and NURF for activation of "stemness" gene-expression programs and proper function of adult HSCs. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

Adolescent Alcohol Exposure-Induced Changes in Alpha-Melanocyte Stimulating Hormone and Neuropeptide Y Pathways via Histone Acetylation in the Brain During Adulthood.

PubMed

Kokare, Dadasaheb M; Kyzar, Evan J; Zhang, Huaibo; Sakharkar, Amul J; Pandey, Subhash C

2017-09-01

Adolescent intermittent ethanol exposure causes long-lasting alterations in brain epigenetic mechanisms. Melanocortin and neuropeptide Y signaling interact and are affected by ethanol exposure in the brain. Here, the persistent effects of adolescent intermittent ethanol on alpha-melanocyte stimulating hormone, melanocortin 4 receptor, and neuropeptide Y expression and their regulation by histone acetylation mechanisms were investigated in adulthood. Male rats were exposed to adolescent intermittent ethanol (2 g/kg, i.p.) or volume-matched adolescent intermittent saline from postnatal days 28 to 41 and allowed to grow to postnatal day 92. Anxiety-like behaviors were measured by the elevated plus-maze test. Brain regions from adult rats were used to examine changes in alpha-melanocyte stimulating hormone, melanocortin 4 receptor, and neuropeptide Y expression and the histone acetylation status of their promoters. Adolescent intermittent ethanol-exposed adult rats displayed anxiety-like behaviors and showed increased pro-opiomelanocortin mRNA levels in the hypothalamus and increased melanocortin 4 receptor mRNA levels in both the amygdala and hypothalamus compared with adolescent intermittent saline-exposed adult rats. The alpha-Melanocyte stimulating hormone and melanocortin 4 receptor protein levels were increased in the central and medial nucleus of the amygdala, paraventricular nucleus, and arcuate nucleus of the hypothalamus in adolescent intermittent ethanol-exposed compared with adolescent intermittent saline-exposed adult rats. Neuropeptide Y protein levels were decreased in the central and medial nucleus of the amygdala of adolescent intermittent ethanol-exposed compared with adolescent intermittent saline-exposed adult rats. Histone H3K9/14 acetylation was decreased in the neuropeptide Y promoter in the amygdala but increased in the melanocortin 4 receptor gene promoter in the amygdala and the melanocortin 4 receptor and pro-opiomelanocortin promoters in the

Nicotine alters MicroRNA expression and hinders human adult stem cell regenerative potential.

PubMed

Ng, Tsz Kin; Carballosa, Carlos M; Pelaez, Daniel; Wong, Hoi Kin; Choy, Kwong Wai; Pang, Chi Pui; Cheung, Herman S

2013-03-01

Adult stem cells are critical for the healing process in regenerative medicine. However, cigarette smoking inhibits stem cell recruitment to tissues and delays the wound-healing process. This study investigated the effect of nicotine, a major constituent in the cigarette smoke, on the regenerative potentials of human mesenchymal stem cells (MSC) and periodontal ligament-derived stem cells (PDLSC). The cell proliferation of 1.0 μM nicotine-treated MSC and PDLSC was significantly reduced when compared to the untreated control. Moreover, nicotine also retarded the locomotion of these adult stem cells. Furthermore, their osteogenic differentiation capabilities were reduced in the presence of nicotine as evidenced by gene expression (RUNX2, ALPL, BGLAP, COL1A1, and COL1A2), calcium deposition, and alkaline phosphatase activity analyses. In addition, the microRNA (miRNA) profile of nicotine-treated PDLSC was altered; suggesting miRNAs might play an important role in the nicotine effects on stem cells. This study provided the possible mechanistic explanations on stem cell-associated healing delay in cigarette smoking.

A role for adult TLX-positive neural stem cells in learning and behaviour.

PubMed

Zhang, Chun-Li; Zou, Yuhua; He, Weimin; Gage, Fred H; Evans, Ronald M

2008-02-21

Neurogenesis persists in the adult brain and can be regulated by a plethora of external stimuli, such as learning, memory, exercise, environment and stress. Although newly generated neurons are able to migrate and preferentially incorporate into the neural network, how these cells are molecularly regulated and whether they are required for any normal brain function are unresolved questions. The adult neural stem cell pool is composed of orphan nuclear receptor TLX-positive cells. Here, using genetic approaches in mice, we demonstrate that TLX (also called NR2E1) regulates adult neural stem cell proliferation in a cell-autonomous manner by controlling a defined genetic network implicated in cell proliferation and growth. Consequently, specific removal of TLX from the adult mouse brain through inducible recombination results in a significant reduction of stem cell proliferation and a marked decrement in spatial learning. In contrast, the resulting suppression of adult neurogenesis does not affect contextual fear conditioning, locomotion or diurnal rhythmic activities, indicating a more selective contribution of newly generated neurons to specific cognitive functions.

Melanocyte biology and function with reference to oral melanin hyperpigmentation in HIV-seropositive subjects.

PubMed

Feller, Liviu; Chandran, Rakesh; Kramer, Beverley; Khammissa, Razia A G; Altini, Mario; Lemmer, Johan

2014-09-01

The color of normal skin and of oral mucosa is not determined by the number of melanocytes in the epithelium but rather by their melanogenic activity. Pigmented biopolymers or melanins are synthesized in melanosomes. Tyrosinase is the critical enzyme in the biosynthesis of both brown/black eumelanin and yellow/red pheomelanin. The number of the melanosomes within the melanocytes, the type of melanin within the melanosomes, and the efficacy of the transfer of melanosomes from the melanocytes to the neighboring keratinocytes all play an important role in tissue pigmentation. Melanin production is regulated by locally produced factors including proopiomelanocortin and its derivative peptides, particularly alpha-melanocyte-stimulating hormone (α-MSH), melanocortin 1 receptor (MC1R), adrenergic and cholinergic agents, growth factors, cytokines, and nitric oxide. Both eumelanin and pheomelanin can be produced by the same melanocytes, and the proportion of the two melanin types is influenced by the degree of functional activity of the α-MSH/MC1R intracellular pathway. The cause of HIV oral melanosis is not fully understood but may be associated with HIV-induced cytokine dysregulation, with the medications commonly prescribed to HIV-seropositive persons, and with adrenocortical dysfunction, which is not uncommon in HIV-seropositive subjects with AIDS. The purpose of this article is to discuss some aspects of melanocyte biology and HIV-associated oral melanin hyperpigmentation.

Molecular mechanisms of gravity-dependent signaling in human melanocytic cells involve cyclic GMP

NASA Astrophysics Data System (ADS)

Ivanova, Krassimira; Lambers, Britta; Block, Ingrid; Bromeis, Birgit; Das, Pranab K.; Gerzer, Rupert

2005-08-01

Gravity alteration (micro- and hypergravity) is known to influence cell functions. As guanosine 3',5'-cyclic monophosphate (cGMP) is an important messenger in melanocyte signaling we have compared the regulation of cGMP levels in human melanocytes and melanoma cells with different metastatic potential under hypergravity conditions. We were able to demonstrate that long-term exposure to hypergravity stimulates cGMP efflux in cultured human melanocytes and non- metastatic melanoma cells, whereas highly metastatic melanoma cells appear to be insensitive to hypergravity, most probably, due to an up-regulated cGMP efflux at 1g. Here we report that these effects are associated with the expression of the multidrug resistance proteins 4 and 5 known to act as selective export pumps for amphiphilic anions like cGMP. Thus, an altered gravity vector may induce cGMP-dependent signaling events in melanocytic cells that could be important for malignant transformation.

Prospects of Pluripotent and Adult Stem Cells for Rare Diseases.

PubMed

García-Castro, Javier; Singeç, Ilyas

2017-01-01

Rare diseases are highly diverse and complex regarding molecular underpinning and clinical manifestation and afflict millions of patients worldwide. The lack of appropriate model systems with face and construct validity and the limited availability of live tissues and cells from patients has largely hampered the understanding of underlying disease mechanisms. As a consequence, there are no adequate treatment options available for the vast majority of rare diseases. Over the last decade, remarkable progress in pluripotent and adult stem cell biology and the advent of powerful genomic technologies opened up exciting new avenues for the investigation, diagnosis, and personalized therapy of intractable human diseases. Utilizing the entire range of available stem cell types will continue to cross-fertilize different research areas and leverage the investigation of rare diseases based on evidence-based medicine. Standardized cell engineering and manufacturing from inexhaustible stem cell sources should lay the foundation for next-generation drug discovery and cell therapies that are broadly applicable in regenerative medicine. In this chapter we discuss how patient- and disease-specific iPS cells as well as adult stem cells are changing the pace of biomedical research and the translational landscape.

Signet ring cell melanocytic nevus: report of a case over trichilemmal cyst and review of the literature.

PubMed

Sabater Marco, Vicente; Escutia Muñoz, Begoña; Morera Faet, Arturo; Botella Estrada, Rafael

2012-02-01

Different melanocytic nevi have been reported as being associated with dermal cysts. Signet ring cell melanocytic nevus is a rare variant of melanocytic nevus characterized by cells with signet ring morphology within a common melanocytic nevus. This article describes an exceptional case of melanocytic nevus composed exclusively of signet ring cells over a trichilemmal cyst. Histologically, above the cyst, there was a small, symmetrical and sharply demarcated lesion showing a compound proliferation of small, round, monomorphous cells with signet ring morphology. Immunohistochemically, signet ring cells were negative for cytokeratin AE1/3, leukocyte common antigen, HMB-45, and CD34. Occasionally, isolated signet ring cells were positive for S-100 and melan A. Melanocytic nevus composed of signet ring cells should raise the differential diagnosis with other cutaneous tumors exhibiting signet ring cells. Previous cases of this entity reported in the literature are also reviewed.

Identification and characterization of putative stem cells in the adult pig ovary.

PubMed

Bui, Hong-Thuy; Van Thuan, Nguyen; Kwon, Deug-Nam; Choi, Yun-Jung; Kang, Min-Hee; Han, Jae-Woong; Kim, Teoan; Kim, Jin-Hoi

2014-06-01

Recently, the concept of 'neo-oogenesis' has received increasing attention, since it was shown that adult mammals have a renewable source of eggs. The purpose of this study was to elucidate the origin of these eggs and to confirm whether neo-oogenesis continues throughout life in the ovaries of the adult mammal. Adult female pigs were utilized to isolate, identify and characterize, including their proliferation and differentiation capabilities, putative stem cells (PSCs) from the ovary. PSCs were found to comprise a heterogeneous population based on c-kit expression and cell size, and also express stem and germ cell markers. Analysis of PSC molecular progression during establishment showed that these cells undergo cytoplasmic-to-nuclear translocation of Oct4 in a manner reminiscent of gonadal primordial germ cells (PGCs). Hence, cells with the characteristics of early PGCs are present or are generated in the adult pig ovary. Furthermore, the in vitro establishment of porcine PSCs required the presence of ovarian cell-derived extracellular regulatory factors, which are also likely to direct stem cell niche interactions in vivo. In conclusion, the present work supports a crucial role for c-kit and kit ligand/stem cell factor in stimulating the growth, proliferation and nuclear reprogramming of porcine PSCs, and further suggests that porcine PSCs might be the culture equivalent of early PGCs. © 2014. Published by The Company of Biologists Ltd.

Isolation, Culture, and Motility Measurements of Epidermal Melanocytes from GFP-Expressing Reporter Mice.

PubMed

Dagnino, Lina; Crawford, Melissa

2018-03-27

In this article, we provide a method to isolate primary epidermal melanocytes from reporter mice, which also allow targeted gene inactivation. The mice from which these cells are isolated are bred into a Rosa26 mT/mG reporter background, which results in GFP expression in the targeted melanocytic cell population. These cells are isolated and cultured to >95% purity. The cells can be used for gene expression studies, clonogenic experiments, and biological assays, such as capacity for migration. Melanocytes are slow moving cells, and we also provide a method to measure motility using individual cell tracking and data analysis.

Conversion of adult endothelium to immunocompetent haematopoietic stem cells

PubMed Central

Lis, Raphael; Karrasch, Charles C.; Poulos, Michael G.; Kunar, Balvir; Redmond, David; Barcia Duran, Jose G.; Badwe, Chaitanya R.; Schachterle, Will; Ginsberg, Michael; Xiang, Jenny; Tabrizi, Arash Rafii; Shido, Koji; Rosenwaks, Zev; Elemento, Olivier; Speck, Nancy; Butler, Jason M.; Scandura, Joseph M.; Rafii, Shahin

2018-01-01

Developmental pathways that orchestrate the fleeting transition of endothelial cells into haematopoietic stem cells remain undefined. Here we demonstrate a tractable approach for fully converting adult mouse endothelial cells to haematopoietic stem cells (rEC-HSCs) through transient expression of genes encoding the transcription factors Fosb, Gfi1, Runx1, and Spi1 (also known as Fgrs) and vascular-niche-derived angiocrine factors. The induction phase (day 0–8) of conversion is initiated by expression of Fgrs in mature endothelial cells, which results in endogenous Runx1 expression. During the specification phase (day 8–20), Runx1+ Fgrs-transduced endothelial cells commit to a haematopoietic fate yielding rEC-HSCs that no longer require Fgrs expression. The vascular niche drives a robust self-renewal and expansion phase of rEC-HSCs (at day 20–28). rEC-HSCs have a transcriptome and long-term self-renewal capacity similar to those of adult haematopoietic stem cells, are competent for clonal engraftment and serial primary and secondary multi-lineage reconstituting potential, including antigen-dependent adaptive immune function. Inhibition of TGF-β and CXCR7 or activation of BMP and CXCR4 signalling enhanced generation of rEC-HSCs. Conversion of endothelial cells into autologous authentic engraftable haematopoietic stem cells could aid treatment of haematological disorders. PMID:28514438

Melanocytic nevi and non-neoplastic hyperpigmentations.

PubMed

Clemente, C

2017-06-01

This is the first of three chapters that will be progressively published on Pathologica as updating activity of the Italian Study Group of Dermatopathology (GISD), Italian Society of Pathology and Cytology (SIAPeC IAP). The first chapter concerns non-neoplastic hyperpigmented skin lesions and nevi, the second will address the topics of dysplastic nevus, borderline and low malignant potential melanocytic proliferations and the third melanoma in its variants and differential diagnoses with a supplement on the immunohistochemistry and molecular support to diagnostic and prognostic definition of nevi and melanomas. Although we believe that great advances were made in the application of ancillary genetic, immunohistochemical and molecular techniques, for the diagnosis and biological characterization of melanocytic tumors the morphology still remains the gold standard. These chapters are not intended as substitutes or even claim to be compared to the numerous and valuable texts that are also recently published, but they want to present, concisely and quickly available, all of those traits that we believe essential to the histopathological evaluation of a melanocytic lesion. No morphological parameter is exclusive and individually sufficient to make the correct diagnosis of nevus or melanoma but to reach a final conclusive and appropriate interpretation a set of morphological characters must be evaluated and compared. I was lucky enough to be able to examine several thousand cases and to draw lessons from each of these increasing my diagnostic experience. I had a great lesson by my teacher and good friend Prof. Martin C. Mihm Jr of Boston, dermato-pathologist with undisputed international reputation, who, with great passion, patience and friendship, transferred me much of his experience and knowledge and for which I always thank him. Special thanks I would like to address Dr. Agostino Crupi, dermatologist, skin-oncologist and brilliant dermatoscopist who taught me how the

Involvement of pigment globules containing multiple melanosomes in the transfer of melanosomes from melanocytes to keratinocytes

PubMed Central

Niki, Yoko; Yoshida, Masaki; Ito, Masaaki; Akiyama, Kaoru; Kim, Jin-Hwa; Yoon, Tae-Jin; Matsui, Mary S; Yarosh, Daniel B; Ichihashi, Masamitsu

2011-01-01

The mechanism of melanosome transfer from melanocytes to keratinocytes has not been fully clarified. We now show a route of melanosome transfer using co-cultures of normal human melanocytes and keratinocytes. Substantial levels of melanosome transfer were elicited in co-cultures of melanocytes and keratinocytes separated by a microporous membrane filter. The melanocyte dendrites penetrated into the keratinocyte layer through the filter and many pigment globules were observed in keratinocytes. Electron microscopic observations revealed that melanosomes incorporated in keratinocytes were packed in clusters enclosed by a double membrane. Numerous pigment globules budded off from melanocyte dendrites and were released into the culture medium. Those pigment globules were filled with multiple melanosomes and a few mitochondria but no nuclei. When those globules were added to the culture medium of keratinocytes, they were incorporated and showed double membrane-enclosed melano-phagolysosomes consistent with the structures obtained from the co-culture system. In contrast, when individual naked melanosomes isolated from melanocytes were added to keratinocytes, they were also phagocytosed by keratinocytes but were enclosed by a single membrane in a manner distinct from the co-culture system. These results suggest a novel mechanism of melanosome transfer, wherein melanosomes are packed in membrane globules that bud off from melanocyte dendrites, where they are released into the extracellular space and then phagocytosed by keratinocytes. PMID:21686100

The Transcription Factors Ets1 and Sox10 Interact During Murine Melanocyte Development

PubMed Central

Saldana-Caboverde, Amy; Perera, Erasmo M.; Watkins-Chow, Dawn; Hansen, Nancy F.; Vemulapalli, Meghana; Mullikin, James C; Pavan, William J.; Kos, Lidia

2015-01-01

Melanocytes, the pigment-producing cells, arise from multipotent neural crest (NC) cells during embryogenesis. Many genes required for melanocyte development were identified using mouse pigmentation mutants. The variable spotting mouse pigmentation mutant arose spontaneously at the Jackson Laboratory. We identified a G-to-A nucleotide transition in exon 3 of the Ets1 gene in variable spotting, which results in a missense G102E mutation. Homozygous variable spotting mice exhibit sporadic white spotting. Similarly, mice carrying a targeted deletion of Ets1 exhibit hypopigmentation; nevertheless, the function of Ets1 in melanocyte development is unknown. The transcription factor Ets1 is widely expressed in developing organs and tissues, including the NC. In the chick, Ets1 is required for the expression of Sox10, a transcription factor critical for the development of various NC derivatives, including melanocytes. We show that Ets1 is required early for murine NC cell and melanocyte precursor survival in vivo. Given the importance of Ets1 for Sox10 expression in the chick, we investigated a potential genetic interaction between these genes by comparing the hypopigmentation phenotypes of single and double heterozygous mice. The incidence of hypopigmentation in double heterozygotes was significantly greater than in single heterozygotes. The area of hypopigmentation in double heterozygotes was significantly larger than would be expected from the addition of the areas of hypopigmentation of single heterozygotes, suggesting that Ets1 and Sox10 interact synergistically in melanocyte development. Since Sox10 is also essential for enteric ganglia development, we examined the distal colons of Ets1 null mutants and found a significant decrease in enteric innervation, which was exacerbated by Sox10 heterozygosity. At the molecular level, Ets1 was found to activate an enhancer critical for Sox10 expression in NC-derived structures. Furthermore, enhancer activation was

Female mice lack adult germ-line stem cells but sustain oogenesis using stable primordial follicles.

PubMed

Lei, Lei; Spradling, Allan C

2013-05-21

Whether or not mammalian females generate new oocytes during adulthood from germ-line stem cells to sustain the ovarian follicle pool has recently generated controversy. We used a sensitive lineage-labeling system to determine whether stem cells are needed in female adult mice to compensate for follicular losses and to directly identify active germ-line stem cells. Primordial follicles generated during fetal life are highly stable, with a half-life during adulthood of 10 mo, and thus are sufficient to sustain adult oogenesis without a source of renewal. Moreover, in normal mice or following germ-cell depletion with Busulfan, only stable, single oocytes are lineage-labeled, rather than cell clusters indicative of new oocyte formation. Even one germ-line stem cell division per 2 wk would have been detected by our method, based on the kinetics of fetal follicle formation. Thus, adult female mice neither require nor contain active germ-line stem cells or produce new oocytes in vivo.

Synergistic use of adult and embryonic stem cells to study human hematopoiesis.

PubMed

Martin, Colin H; Kaufman, Dan S

2005-10-01

Embryonic stem cells (ESCs) and adult stem cells both provide important resources to define the mechanisms of hematopoietic cell development. To date, studies that utilize hematopoietic stem cells (HSCs) isolated from sites such as bone marrow or umbilical cord blood have been the primary means to identify molecular and phenotypic characteristics of blood cell populations able to mediate long-term hematopoietic engraftment. Although these HSCs are very useful clinically, they are difficult to expand in culture. Now, basic research on human ESCs provides opportunities for novel investigations into the mechanisms of HSC self-renewal. Eventually, the long history of basic and clinical research with adult hematopoietic cell transplantation could translate to establish human ESCs as a suitable alternative starting cell source for clinical hematopoietic reconstitution.

Hepatocyte growth factor/scatter factor-MET signaling in neural crest-derived melanocyte development.

PubMed

Kos, L; Aronzon, A; Takayama, H; Maina, F; Ponzetto, C; Merlino, G; Pavan, W

1999-02-01

The mechanisms governing development of neural crest-derived melanocytes, and how alterations in these pathways lead to hypopigmentation disorders, are not completely understood. Hepatocyte growth factor/scatter factor (HGF/SF) signaling through the tyrosine-kinase receptor, MET, is capable of promoting the proliferation, increasing the motility, and maintaining high tyrosinase activity and melanin synthesis of melanocytes in vitro. In addition, transgenic mice that ubiquitously overexpress HGF/SF demonstrate hyperpigmentation in the skin and leptomenigenes and develop melanomas. To investigate whether HGF/ SF-MET signaling is involved in the development of neural crest-derived melanocytes, transgenic embryos, ubiquitously overexpressing HGF/SF, were analyzed. In HGF/SF transgenic embryos, the distribution of melanoblasts along the characteristic migratory pathway was not affected. However, additional ectopically localized melanoblasts were also observed in the dorsal root ganglia and neural tube, as early as 11.5 days post coitus (p.c.). We utilized an in vitro neural crest culture assay to further explore the role of HGF/SF-MET signaling in neural crest development. HGF/SF added to neural crest cultures increased melanoblast number, permitted differentiation into pigmented melanocytes, promoted melanoblast survival, and could replace mast-cell growth factor/Steel factor (MGF) in explant cultures. To examine whether HGF/SF-MET signaling is required for the proper development of melanocytes, embryos with a targeted Met null mutation (Met-/-) were analysed. In Met-/- embryos, melanoblast number and location were not overtly affected up to 14 days p.c. These results demonstrate that HGF/SF-MET signaling influences, but is not required for, the initial development of neural crest-derived melanocytes in vivo and in vitro.

Characterization of TLX expression in neural stem cells and progenitor cells in adult brains.

PubMed

Li, Shengxiu; Sun, Guoqiang; Murai, Kiyohito; Ye, Peng; Shi, Yanhong

2012-01-01

TLX has been shown to play an important role in regulating the self-renewal and proliferation of neural stem cells in adult brains. However, the cellular distribution of endogenous TLX protein in adult brains remains to be elucidated. In this study, we used immunostaining with a TLX-specific antibody to show that TLX is expressed in both neural stem cells and transit-amplifying neural progenitor cells in the subventricular zone (SVZ) of adult mouse brains. Then, using a double thymidine analog labeling approach, we showed that almost all of the self-renewing neural stem cells expressed TLX. Interestingly, most of the TLX-positive cells in the SVZ represented the thymidine analog-negative, relatively quiescent neural stem cell population. Using cell type markers and short-term BrdU labeling, we demonstrated that TLX was also expressed in the Mash1+ rapidly dividing type C cells. Furthermore, loss of TLX expression dramatically reduced BrdU label-retaining neural stem cells and the actively dividing neural progenitor cells in the SVZ, but substantially increased GFAP staining and extended GFAP processes. These results suggest that TLX is essential to maintain the self-renewing neural stem cells in the SVZ and that the GFAP+ cells in the SVZ lose neural stem cell property upon loss of TLX expression. Understanding the cellular distribution of TLX and its function in specific cell types may provide insights into the development of therapeutic tools for neurodegenerative diseases by targeting TLX in neural stem/progenitors cells.

Automatic Classification of Specific Melanocytic Lesions Using Artificial Intelligence.

PubMed

Jaworek-Korjakowska, Joanna; Kłeczek, Paweł

2016-01-01

Given its propensity to metastasize, and lack of effective therapies for most patients with advanced disease, early detection of melanoma is a clinical imperative. Different computer-aided diagnosis (CAD) systems have been proposed to increase the specificity and sensitivity of melanoma detection. Although such computer programs are developed for different diagnostic algorithms, to the best of our knowledge, a system to classify different melanocytic lesions has not been proposed yet. In this research we present a new approach to the classification of melanocytic lesions. This work is focused not only on categorization of skin lesions as benign or malignant but also on specifying the exact type of a skin lesion including melanoma, Clark nevus, Spitz/Reed nevus, and blue nevus. The proposed automatic algorithm contains the following steps: image enhancement, lesion segmentation, feature extraction, and selection as well as classification. The algorithm has been tested on 300 dermoscopic images and achieved accuracy of 92% indicating that the proposed approach classified most of the melanocytic lesions correctly. A proposed system can not only help to precisely diagnose the type of the skin mole but also decrease the amount of biopsies and reduce the morbidity related to skin lesion excision.

The unfolded protein response in melanocytes: activation in response to chemical stressors of the endoplasmic reticulum and tyrosinase misfolding.

PubMed

Manga, Prashiela; Bis, Sabina; Knoll, Kristen; Perez, Beremis; Orlow, Seth J

2010-10-01

Accumulation of proteins in the endoplasmic reticulum (ER) triggers the unfolded protein response (UPR), comprising three signaling pathways initiated by Ire1, Perk and Atf6 respectively. Unfolded protein response activation was compared in chemically stressed murine wildtype melanocytes and mutant melanocytes that retain tyrosinase in the ER. Thapsigargin, an ER stressor, activated all pathways in wildtype melanocytes, triggering Caspase 12-mediated apoptosis at toxic doses. Albino melanocytes expressing mutant tyrosinase showed evidence of ER stress with increased Ire1 expression, but the downstream effector, Xbp1, was not activated even following thapsigargin treatment. Attenuation of Ire1 signaling was recapitulated in wildtype melanocytes treated with thapsigargin for 8 days, with diminished Xbp1 activation observed after 4 days. Atf6 was also activated in albino melanocytes, with no response to thapsigargin, while the Perk pathway was not activated and thapsigargin treatment elicited robust expression of the downstream effector CCAAT-enhancer-binding protein homologous protein. Thus, melanocytes adapt to ER stress by attenuating two UPR pathways.

A planarian p53 homolog regulates proliferation and self-renewal in adult stem cell lineages.

PubMed

Pearson, Bret J; Sánchez Alvarado, Alejandro

2010-01-01

The functions of adult stem cells and tumor suppressor genes are known to intersect. However, when and how tumor suppressors function in the lineages produced by adult stem cells is unknown. With a large population of stem cells that can be manipulated and studied in vivo, the freshwater planarian is an ideal system with which to investigate these questions. Here, we focus on the tumor suppressor p53, homologs of which have no known role in stem cell biology in any invertebrate examined thus far. Planaria have a single p53 family member, Smed-p53, which is predominantly expressed in newly made stem cell progeny. When Smed-p53 is targeted by RNAi, the stem cell population increases at the expense of progeny, resulting in hyper-proliferation. However, ultimately the stem cell population fails to self-renew. Our results suggest that prior to the vertebrates, an ancestral p53-like molecule already had functions in stem cell proliferation control and self-renewal.

Topography of Protein Kinase C βII in Benign and Malignant Melanocytic Lesions.

PubMed

Krasagakis, Konstanin; Tsentelierou, Eleftheria; Chlouverakis, Gregory; Stathopoulos, Efstathios N

2017-09-01

Protein kinase C βII promotes melanogenesis and affects proliferation of melanocytic cells but is frequently absent or decreased in melanoma cells in vitro. To investigate PKC-βII expression and spatial distribution within a lesion in various benign and malignant melanocytic proliferations. Expression of PKC-βII was semiquantitatively assessed in the various existing compartments (intraepidermal [not nested], junctional [nested], and dermal) of benign (n = 43) and malignant (n = 28) melanocytic lesions by immunohistochemistry. Melanocytes in the basal layer of normal skin or in lentigo simplex stained strongly for PKC-βII. Common nevi lacked completely PKC-βII. All other lesions expressed variably PKC-βII, with cutaneous melanoma metastases displaying the lowest rate of positivity (14%). In the topographical analysis within a lesion, PKC-βII expression was largely retained in the intraepidermal and junctional part of all other lesions (dysplastic nevus, lentigo maligna, and melanoma). Reduced expression of PKC-βII was found in the dermal component of benign and malignant lesions ( P = .041 vs intraepidermal). PKC-βII expression in the various compartments did not differ significantly between benign and malignant lesions. The current study revealed a significant correlation between PKC-βII expression and spatial localization of melanocytes, with the lowest expression found in the dermal compartment and the highest in the epidermal compartment.

Amides from Piper nigrum L. with dissimilar effects on melanocyte proliferation in-vitro.

PubMed

Lin, Zhixiu; Liao, Yonghong; Venkatasamy, Radhakrishnan; Hider, Robert C; Soumyanath, Amala

2007-04-01

Melanocyte proliferation stimulants are of interest as potential treatments for the depigmentary skin disorder, vitiligo. Piper nigrum L. (Piperaceae) fruit (black pepper) water extract and its main alkaloid, piperine (1), promote melanocyte proliferation in-vitro. A crude chloroform extract of P. nigrum containing piperine was more stimulatory than an equivalent concentration of the pure compound, suggesting the presence of other active components. Piperine (1), guineensine (2), pipericide (3), N-feruloyltyramine (4) and N-isobutyl-2E, 4E-dodecadienamide (5) were isolated from the chloroform extract. Their activity was compared with piperine and with commercial piperlongumine (6) and safrole (7), and synthetically prepared piperettine (8), piperlonguminine (9) and 1-(3, 4-methylenedioxyphenyl)-decane (10). Compounds 6-10 either occur in P. nigrum or are structurally related. Compounds 1, 2, 3, 8 and 9 stimulated melanocyte proliferation, whereas 4, 5, 6, 7 and 10 did not. Comparison of structures suggests that the methylenedioxyphenyl function is essential for melanocyte stimulatory activity. Only those compounds also possessing an amide group were active, although the amino component of the amide group and chain linking it to the methylenedioxyphenyl group can vary. P. nigrum, therefore, contains several amides with the ability to stimulate melanocyte proliferation. This finding supports the traditional use of P. nigrum extracts in vitiligo and provides new lead compounds for drug development for this disease.

Distinctive eosinophilic cytoplasmic inclusion bodies in melanocytic nevi: an immunohistochemical and ultrastructural study.

PubMed

Shon, Wonwoo; Wada, David A; Gibson, Lawrence E; Flotte, Thomas J; Scheithauer, Bernd W

2011-11-01

We sought to further determine the histochemical, immunohistochemical and ultrastructural properties of eosinophilic cytoplasmic inclusion bodies in melanocytic nevi. Skin specimens from four patients with a known diagnosis of conventional melanocytic nevus (3) or Spitz nevus (1) and containing intracytoplasmic eosinophilic inclusion bodies were selected. In addition, melanomas (25), Spitz nevi (10) and blue nevi (4) were examined to determine the frequency of the inclusions. Inclusions tended to be located in multinucleated melanocytes with abundant vacuolated cytoplasm. In conventional (hematoxylin and eosin-stained) sections, the degree of density and eosinophilia of intracytoplasmic inclusions varied with size. Periodic acid-Schiff, Fontana and Congo red stains showed no reactivity. All bodies were immunoreactive for ubiquitin but negative for tyrosinase, keratin and vimentin. Ultrastructurally, inclusion bodies were non-membrane bound, ranged from 4 to 7 µm, and were comprised of radiating filamentous structures with or without an electron-dense core. Electron probe x-ray microanalysis revealed no significant peaks. None of additional melanomas, Spitz nevi and blue nevi that were evaluated showed similar inclusions. The inclusion bodies described herein bear no resemblance to other cytoplasmic inclusion bodies previously described in melanocytic lesions. There is no discernible relationship to melanosomes by ultrastructural analysis. We postulate a relationship with dysfunction of ubiquitin-mediated protein degradation occurring in melanocytes. Copyright © 2011 John Wiley & Sons A/S.

Wnt Signaling in Adult Epithelial Stem Cells and Cancer.

PubMed

Tan, Si Hui; Barker, Nick

2018-01-01

Wnt/β-catenin signaling is integral to the homeostasis and regeneration of many epithelial tissues due to its critical role in adult stem cell regulation. It is also implicated in many epithelial cancers, with mutations in core pathway components frequently present in patient tumors. In this chapter, we discuss the roles of Wnt/β-catenin signaling and Wnt-regulated stem cells in homeostatic, regenerative and cancer contexts of the intestines, stomach, skin, and liver. We also examine the sources of Wnt ligands that form part of the stem cell niche. Despite the diversity in characteristics of various tissue stem cells, the role(s) of Wnt/β-catenin signaling is generally coherent in maintaining stem cell fate and/or promoting proliferation. It is also likely to play similar roles in cancer stem cells, making the pathway a salient therapeutic target for cancer. While promising progress is being made in the field, deeper understanding of the functions and signaling mechanisms of the pathway in individual epithelial tissues will expedite efforts to modulate Wnt/β-catenin signaling in cancer treatment and tissue regeneration. Copyright © 2018 Elsevier Inc. All rights reserved.

A putative mesenchymal stem cells population isolated from adult human testes.

PubMed

Gonzalez, R; Griparic, L; Vargas, V; Burgee, K; Santacruz, P; Anderson, R; Schiewe, M; Silva, F; Patel, A

2009-08-07

Mesenchymal stem cells (MSCs) isolated from several adult human tissues are reported to be a promising tool for regenerative medicine. In order to broaden the array of tools for therapeutic application, we isolated a new population of cells from adult human testis termed gonadal stem cells (GSCs). GSCs express CD105, CD166, CD73, CD90, STRO-1 and lack hematopoietic markers CD34, CD45, and HLA-DR which are characteristic identifiers of MSCs. In addition, GSCs express pluripotent markers Oct4, Nanog, and SSEA-4. GSCs propagated for at least 64 population doublings and exhibited clonogenic capability. GSCs have a broad plasticity and the potential to differentiate into adipogenic, osteogenic, and chondrogenic cells. These studies demonstrate that GSCs are easily obtainable stem cells, have growth kinetics and marker expression similar to MSCs, and differentiate into mesodermal lineage cells. Therefore, GSCs may be a valuable tool for therapeutic applications.

Role of nitric oxide and cyclic GMP signaling in melanocyte response to hypergravity

NASA Astrophysics Data System (ADS)

Ivanova, Krassimira; Lambers, Britta; Tsiockas, Wasiliki; Block, Ingrid; Gerzer, Rupert

Nitric oxide (NO) has a prominent role in many (patho)physiological processes in the skin including erythema, inflammation, and cancerogenesis. The soluble guanylyl cyclase (sGC), a key transducer in NO signaling, catalyzes the formation of the second messenger guanosine 3´,5´-cyclic monophosphate (cyclic cGMP or cGMP). For human melanocytes, which are responsible for skin pigmentation by synthesizing the pigment melanin, it has been reported that the NO/sGC/cGMP pathway is involved in UVB-induced melanogenesis. Melanin acts as a scavenger for free radicals that may arise during metabolic stress. It may also act as a photosensitizer that generates active oxygen species upon UV irradiation, which may initiate hypopigmentary disorders (e.g., vitiligo) as well as UV-induced oncogene cell transformation. In addition, melanoma, a deadly skin cancer, which arises from transformed melanocytes, is characterized by a resistance to chemotherapy. In our studies we have shown that NO can induce perturbation of melanocyte-extracellular matrix component interactions, which may contribute to loss of melanocytes or melanoma metastasis. Such NO effects appear to be modulated partly via cGMP. Moreover, we found that different guanylyl cyclase isoforms are responsible for cGMP synthesis in melanocytic cells. Normal human melanocytes and nonmetastatic melanoma cells predominantly express sGC, which appears to be associated with melanogenesis, whereas absence of NO-sensitive GC, but up-regulated activities of the natriuretic peptide-sensitive membrane guanylyl cyclase isoforms were found in highly metastatic phenotypes. Due to the growing interest in the regulation of signaling activities in normal and transformed cells under altered gravity conditions, we have further investigated whether the NO/cGMP signaling is involved in melanocyte response to gravitational stress. We found that normal human melanocytes and non-metastatic melanoma cell lines, but not highly metastatic cells

Pump-Probe Imaging Differentiates Melanoma from Melanocytic Nevi

PubMed Central

Matthews, Thomas E.; Piletic, Ivan R.; Selim, M. Angelica; Simpson, Mary Jane; Warren, Warren S.

2012-01-01

Melanoma diagnosis is clinically challenging; the accuracy of visual inspection by dermatologists is highly variable and heavily weighted toward false positives. Even the current gold standard of biopsy results in varying diagnoses among pathologists. We have developed a multiphoton technique (based on pump-probe spectroscopy) that directly determines the microscopic distribution of eumelanin and pheomelanin in pigmented lesions of human skin. Our initial results showed a marked difference in the chemical variety of melanin between nonmalignant nevi and melanoma, as well as a number of substantial architectural differences. We examined slices from 42 pigmented lesions and found that melanomas had an increased eumelanin content compared to nonmalignant nevi. When used as a diagnostic criterion, the ratio of eumelanin to pheomelanin captured all investigated melanomas but excluded three-quarters of dysplastic nevi and all benign dermal nevi. Evaluating architectural and cytological features revealed by multiphoton imaging, including the maturation of melanocytes, presence of pigmented melanocytes in the dermis, number and location of melanocytic nests, and confluency of pigmented cells in the epidermis, further increased specificity, allowing rejection of more than half of the remaining false-positive results. We then adapted this multiphoton imaging technique to hematoxylin and eosin (H&E)–stained slides. By adding melanin chemical contrast to H&E-stained slides, pathologists will gain complementary information to increase the ease and accuracy of melanoma diagnosis. PMID:21346168

Induced adult stem (iAS) cells and induced transit amplifying progenitor (iTAP) cells-a possible alternative to induced pluripotent stem (iPS) cells?

PubMed

Heng, Boon Chin; Richards, Mark; Ge, Zigang; Shu, Yimin

2010-02-01

The successful derivation of iPSC lines effectively demonstrates that it is possible to reset the 'developmental clock' of somatic cells all the way back to the initial embryonic state. Hence, it is plausible that this clock may instead be turned back half-way to a less immature developmental stage that is more directly applicable to clinical therapeutic applications or for in vitro pharmacology/toxicology screening assays. Such a suitable developmental state is postulated to be either the putative transit amplifying progenitor stage or adult stem cell stage. It is hypothetically possible to reprogram mature and terminally differentiated somatic cells back to the adult stem cell or transit amplifying progenitor stage, in a manner similar to the derivation of iPSC. It is proposed that the terminology 'Induced Adult Stem Cells' (iASC) or 'Induced Transit Amplifying Progenitor Cells' (iTAPC) be used to described such reprogrammed somatic cells. Of particular interest, is the possibility of resetting the developmental clock of mature differentiated somatic cells of the mesenchymal lineage, explanted from adipose tissue, bone marrow and cartilage. The putative adult stem cell sub-population from which these cells are derived, commonly referred to as 'mesenchymal stem cells', are highly versatile and hold much therapeutic promise in regenerative medicine, as attested to by numerous human clinical trials and animal studies. Perhaps it may be appropriate to term such reprogrammed cells as 'Induced Mesenchymal Stem Cells' (iMSC) or as 'Induced Mesenchumal Progenitor Cells' (iMPC). Given that cells from the same organ/tissue will share some commonalities in gene expression, we hypothesize that the generation of iASC or iTAPC would be more efficient as compared to iPSC generation, since a common epigenetic program must exist between the reprogrammed cells, adult stem cell or progenitor cell types and terminally differentiated cell types from the same organ/tissue.

A role for tyrosinase-related protein 1 in 4-tert-butylphenol-induced toxicity in melanocytes: Implications for vitiligo.

PubMed

Manga, Prashiela; Sheyn, David; Yang, Fan; Sarangarajan, Rangaprasad; Boissy, Raymond E

2006-11-01

Vitiligo presents with depigmented cutaneous lesions following localized melanocyte death. Multiple factors contribute to cell death, including genetically determined susceptibility to trauma, and environmental factors, such as exposure to 4-tert-butylphenol (4-TBP). We demonstrate that 4-TBP induces oxidative stress that is more readily overcome by melanocytes from normally pigmented individuals than from two individuals with vitiligo. The antioxidant catalase selectively and significantly reduced death of melanocytes derived from two individuals with vitiligo, indicating a role for oxidative stress in vitiligo pathogenesis. In normal melanocytes, oxidative stress results in reduced expression of microphthalmia-associated transcription factor (MITF). Melanocyte-stimulating hormone-induced expression of MITF protein caused increased sensitivity to 4-TBP, whereas sensitivity of melanomas correlated with MITF expression. MITF stimulates melanin synthesis by up-regulating expression of melanogenic enzymes such as tyrosinase-related protein-1 (Tyrp1). Although melanin content per se did not affect sensitivity to 4-TBP, expression of Tyrp1 significantly increased sensitivity. Melanocytes and melanomas that express functional Tyrp1 were significantly more sensitive to 4-TBP than Tyrp1-null cells. Thus, normal melanocytes respond to 4-TBP by reducing expression of MITF and Tyrp1. We hypothesize that melanocytes in vitiligo demonstrate reduced ability to withstand oxidative stress due, partly, to a disruption in MITF regulation of Tyrp1.

A Subpopulation of Smooth Muscle Cells, Derived from Melanocyte-Competent Precursors, Prevents Patent Ductus Arteriosus

PubMed Central

Puig, Isabel; Champeval, Delphine; Kumasaka, Mayuko; Belloir, Elodie; Bonaventure, Jacky; Mark, Manuel; Yamamoto, Hiroaki; Taketo, Mark M.; Choquet, Philippe; Etchevers, Heather C.; Beermann, Friedrich; Delmas, Véronique; Monassier, Laurent; Larue, Lionel

2013-01-01

Background Patent ductus arteriosus is a life-threatening condition frequent in premature newborns but also present in some term infants. Current mouse models of this malformation generally lead to perinatal death, not reproducing the full phenotypic spectrum in humans, in whom genetic inheritance appears complex. The ductus arteriosus (DA), a temporary fetal vessel that bypasses the lungs by shunting the aortic arch to the pulmonary artery, is constituted by smooth muscle cells of distinct origins (SMC1 and SMC2) and many fewer melanocytes. To understand novel mechanisms preventing DA closure at birth, we evaluated the importance of cell fate specification in SMC that form the DA during embryonic development. Upon specific Tyr::Cre-driven activation of Wnt/β-catenin signaling at the time of cell fate specification, melanocytes replaced the SMC2 population of the DA, suggesting that SMC2 and melanocytes have a common precursor. The number of SMC1 in the DA remained similar to that in controls, but insufficient to allow full DA closure at birth. Thus, there was no cellular compensation by SMC1 for the loss of SMC2. Mice in which only melanocytes were genetically ablated after specification from their potential common precursor with SMC2, demonstrated that differentiated melanocytes themselves do not affect DA closure. Loss of the SMC2 population, independent of the presence of melanocytes, is therefore a cause of patent ductus arteriosus and premature death in the first months of life. Our results indicate that patent ductus arteriosus can result from the insufficient differentiation, proliferation, or contractility of a specific smooth muscle subpopulation that shares a common neural crest precursor with cardiovascular melanocytes. PMID:23382837

Patterned femtosecond-laser ablation of Xenopus laevis melanocytes for studies of cell migration, wound repair, and developmental processes

PubMed Central

Mondia, Jessica P.; Adams, Dany S.; Orendorff, Ryan D.; Levin, Michael; Omenetto, Fiorenzo G.

2011-01-01

Ultrafast (femtosecond) lasers have become an important tool to investigate biological phenomena because of their ability to effect highly localized tissue removal in surgical applications. Here we describe programmable, microscale, femtosecond-laser ablation of melanocytes found on Xenopus laevis tadpoles, a technique that is applicable to biological studies in development, regeneration, and cancer research. We illustrate laser marking of individual melanocytes, and the drawing of patterns on melanocyte clusters to help track their migration and/or regeneration. We also demonstrate that this system can upgrade scratch tests, a technique used widely with cultured cells to study cell migration and wound healing, to the more realistic in vivo realm, by clearing a region of melanocytes and monitoring their return over time. In addition, we show how melanocyte ablation can be used for loss-of-function experiments by damaging neighboring tissue, using the example of abnormal tail regeneration following localized spinal cord damage. Since the size, shape, and depth of melanocytes vary as a function of tadpole age and melanocyte location (head or tail), an ablation threshold chart is given. Mechanisms of laser ablation are also discussed. PMID:21833375

Patterned femtosecond-laser ablation of Xenopus laevis melanocytes for studies of cell migration, wound repair, and developmental processes.

PubMed

Mondia, Jessica P; Adams, Dany S; Orendorff, Ryan D; Levin, Michael; Omenetto, Fiorenzo G

2011-08-01

Ultrafast (femtosecond) lasers have become an important tool to investigate biological phenomena because of their ability to effect highly localized tissue removal in surgical applications. Here we describe programmable, microscale, femtosecond-laser ablation of melanocytes found on Xenopus laevis tadpoles, a technique that is applicable to biological studies in development, regeneration, and cancer research. We illustrate laser marking of individual melanocytes, and the drawing of patterns on melanocyte clusters to help track their migration and/or regeneration. We also demonstrate that this system can upgrade scratch tests, a technique used widely with cultured cells to study cell migration and wound healing, to the more realistic in vivo realm, by clearing a region of melanocytes and monitoring their return over time. In addition, we show how melanocyte ablation can be used for loss-of-function experiments by damaging neighboring tissue, using the example of abnormal tail regeneration following localized spinal cord damage. Since the size, shape, and depth of melanocytes vary as a function of tadpole age and melanocyte location (head or tail), an ablation threshold chart is given. Mechanisms of laser ablation are also discussed.

Melanocytes and melanin represent a first line of innate immunity against Candida albicans.

PubMed

Tapia, Cecilia V; Falconer, Maryanne; Tempio, Fabián; Falcón, Felipe; López, Mercedes; Fuentes, Marisol; Alburquenque, Claudio; Amaro, José; Bucarey, Sergio A; Di Nardo, Anna

2014-07-01

Melanocytes are dendritic cells located in the skin and mucosae that synthesize melanin. Some infections induce hypo- or hyperpigmentation, which is associated with the activation of Toll-like receptors (TLRs), especially TLR4. Candida albicans is an opportunist pathogen that can switch between blastoconidia and hyphae forms; the latter is associated with invasion. Our objectives in this study were to ascertain whether C. albicans induces pigmentation in melanocytes and whether this process is dependent on TLR activation, as well as relating this with the antifungal activity of melanin as a first line of innate immunity against fungal infections. Normal human melanocytes were stimulated with C. albicans supernatants or with crude extracts of the blastoconidia or hyphae forms, and pigmentation and TLR2/TLR4 expression were measured. Expression of the melanosomal antigens Melan-A and gp100 was examined for any correlation with increased melanin levels or antifungal activity in melanocyte lysates. Melanosomal antigens were induced earlier than cell pigmentation, and hyphae induced stronger melanization than blastoconidia. Notably, when melanocytes were stimulated with crude extracts of C. albicans, the cell surface expression of TLR2/TLR4 began at 48 h post-stimulation and peaked at 72 h. At this time, blastoconidia induced both TLR2 and TLR4 expression, whereas hyphae only induced TLR4 expression. Taken together, these results suggest that melanocytes play a key role in innate immune responses against C. albicans infections by recognizing pathogenic forms of C. albicans via TLR4, resulting in increased melanin content and inhibition of infection. © The Author 2014. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The protease-activated receptor 2 regulates pigmentation via keratinocyte-melanocyte interactions.

PubMed

Seiberg, M; Paine, C; Sharlow, E; Andrade-Gordon, P; Costanzo, M; Eisinger, M; Shapiro, S S

2000-01-10

Close association exists between melanocytes, the pigment melanin-producing cells in the body, and their neighboring keratinocytes. Keratinocytes are the pigment recipients and skin pigmentation is the result of this interaction. While the chemical basis of melanin production (melanogenesis) is well documented, the molecular mechanism of melanosome transfer needs to be elucidated. We are now providing first evidence that the protease-activated receptor 2 (PAR-2) expressed on keratinocytes, but not on melanocytes, is involved in melanosome transfer and therefore may regulate pigmentation. Activation of PAR-2 with trypsin or with the peptide agonist SLIGRL induced pigmentation in both two- and three-dimensional cocultures of keratinocytes and melanocytes, but not in cocultures that were spatially separated, indicating the need for intimate cell-cell contact. Topical application of SLIGRL on human skin transplanted on SCID mice resulted in a visible skin darkening. Histological examination revealed increased deposits of melanin in the keratinocytes. Inhibition of PAR-2 activation by RWJ-50353, a serine protease inhibitor, resulted in depigmentation and changes in expression of melanogenic-specific genes. Keratinocyte-melanocyte contact was essential for this depigmenting effect. Topical application of this inhibitor induced lightening of the dark skin Yucatan swine, which was confirmed by histochemical analysis. The results presented here suggest a novel mechanism for the regulation of pigmentation, mediated by the activation or inhibition of the keratinocyte receptor PAR-2. Copyright 2000 Academic Press.

Alternative splicing of the tyrosinase gene transcript in normal human melanocytes and lymphocytes.

PubMed

Fryer, J P; Oetting, W S; Brott, M J; King, R A

2001-11-01

We have identified and isolated ectopically expressed tyrosinase transcripts in normal human melanocytes and lymphocytes and in a human melanoma (MNT-1) cell line to establish a baseline for the expression pattern of this gene in normal tissue. Tyrosinase mRNA from human lymphoblastoid cell lines was reverse transcribed and amplified using specific "nested" primers. This amplification yielded eight identifiable transcripts; five that resulted from alternative splicing patterns arising from the utilization of normal and alternative splice sequences. Identical splicing patterns were found in transcripts from human primary melanocytes in culture and a melanoma cell line, indicating that lymphoblastoid cell lines provide an accurate reflection of transcript processing in melanocytes. Similar splicing patterns have also been found with murine melanocyte tyrosinase transcripts. Our results demonstrate that alternative splicing of human tyrosinase gene transcript produces a number of predictable and identifiable transcripts, and that human lymphoblastoid cell lines provide a source of ectopically expressed transcripts that can be used to study the biology of tyrosinase gene expression in humans.

Characterization of TLX Expression in Neural Stem Cells and Progenitor Cells in Adult Brains

PubMed Central

Li, Shengxiu; Sun, Guoqiang; Murai, Kiyohito; Ye, Peng; Shi, Yanhong

2012-01-01

TLX has been shown to play an important role in regulating the self-renewal and proliferation of neural stem cells in adult brains. However, the cellular distribution of endogenous TLX protein in adult brains remains to be elucidated. In this study, we used immunostaining with a TLX-specific antibody to show that TLX is expressed in both neural stem cells and transit-amplifying neural progenitor cells in the subventricular zone (SVZ) of adult mouse brains. Then, using a double thymidine analog labeling approach, we showed that almost all of the self-renewing neural stem cells expressed TLX. Interestingly, most of the TLX-positive cells in the SVZ represented the thymidine analog-negative, relatively quiescent neural stem cell population. Using cell type markers and short-term BrdU labeling, we demonstrated that TLX was also expressed in the Mash1+ rapidly dividing type C cells. Furthermore, loss of TLX expression dramatically reduced BrdU label-retaining neural stem cells and the actively dividing neural progenitor cells in the SVZ, but substantially increased GFAP staining and extended GFAP processes. These results suggest that TLX is essential to maintain the self-renewing neural stem cells in the SVZ and that the GFAP+ cells in the SVZ lose neural stem cell property upon loss of TLX expression.Understanding the cellular distribution of TLX and its function in specific cell types may provide insights into the development of therapeutic tools for neurodegenerative diseases by targeting TLX in neural stem/progenitors cells. PMID:22952666

A reporter mouse model for in vivo tracing and in vitro molecular studies of melanocytic lineage cells and their diseases

PubMed Central

Crawford, Melissa; Leclerc, Valerie

2017-01-01

ABSTRACT Alterations in melanocytic lineage cells give rise to a plethora of distinct human diseases, including neurocristopathies, cutaneous pigmentation disorders, loss of vision and hearing, and melanoma. Understanding the ontogeny and biology of melanocytic cells, as well as how they interact with their surrounding environment, are key steps in the development of therapies for diseases that involve this cell lineage. Efforts to culture and characterize primary melanocytes from normal or genetically engineered mouse models have at times yielded contrasting observations. This is due, in part, to differences in the conditions used to isolate, purify and culture these cells in individual studies. By breeding ROSAmT/mG and Tyr::CreERT2 mice, we generated animals in which melanocytic lineage cells are identified through expression of green fluorescent protein. We also used defined conditions to systematically investigate the proliferation and migration responses of primary melanocytes on various extracellular matrix (ECM) substrates. Under our culture conditions, mouse melanocytes exhibit doubling times in the range of 10 days, and retain exponential proliferative capacity for 50-60 days. In culture, these melanocytes showed distinct responses to different ECM substrates. Specifically, laminin-332 promoted cell spreading, formation of dendrites, random motility and directional migration. In contrast, low or intermediate concentrations of collagen I promoted adhesion and acquisition of a bipolar morphology, and interfered with melanocyte forward movements. Our systematic evaluation of primary melanocyte responses emphasizes the importance of clearly defining culture conditions for these cells. This, in turn, is essential for the interpretation of melanocyte responses to extracellular cues and to understand the molecular basis of disorders involving the melanocytic cell lineage. PMID:28642245

Inhibitory effect of Korean Red Ginseng on melanocyte proliferation and its possible implication in GM-CSF mediated signaling

PubMed Central

Oh, Chang Taek; Park, Jong Il; Jung, Yi Ra; Joo, Yeon Ah; Shin, Dong Ha; Cho, Hyoung Joo; Ahn, Soo Mi; Lim, Young-Ho; Park, Chae Kyu; Hwang, Jae Sung

2013-01-01

Korean Red Ginseng (KRG) has been reported to exert anticancer, anti-oxidant, and anti-inflammatory effects. However, there has been no report on the effect of KRG on skin pigmentation. In this study, we investigated the inhibitory effect of KRG on melanocyte proliferation. KRG extract (KRGE) at different concentrations had no effect on melanin synthesis in melan-A melanocytes. Saponin of KRG (SKRG) inhibited melanin content to 80% of the control at 100 ppm. Keratinocyte-derived factors induced by UV-irradiation were reported to stimulate melanogenesis, differentiation, proliferation, and dendrite formation. In this study, treatment of melan-A melanocytes with conditioned media from UV-irradiated SP-1 keratinocytes increased melanocyte proliferation. When UV-irradiated SP-1 keratinocytes were treated with KRGE or SKRG, the increase of melanocyte proliferation by the conditioned media was blocked. Granulocyte-macrophage colony-stimulating factor (GM-CSF) was produced and released from UV-irradiated keratinocytes. This factor has been reported to be involved in regulating the proliferation and differentiation of epidermal melanocytes. In this study, GM-CSF was significantly increased in SP-1 keratinocytes by UVB irradiation (30 mJ/cm2), and the proliferation of melan-A melanocytes increased significantly by GM-CSF treatment. In addition, the proliferative effect of keratinocyte-conditioned media on melan-A melanocytes was blocked by anti-GM-CSF treatment. KRGE or SKRG treatment decreased the expression of GM-CSF in SP-1 keratinocytes induced by UVB irradiation. These results demonstrate that UV irradiation induced GM-CSF expression in keratinocytes and KRGE or SKRG inhibited its expression. Therefore, KRG could be a good candidate for regulating UV-induced melanocyte proliferation. PMID:24235857

Gadobutrol Versus Gadopentetate Dimeglumine or Gadobenate Dimeglumine Before DCE-MRI in Diagnosing Patients With Multiple Sclerosis, Grade II-IV Glioma, or Brain Metastases

ClinicalTrials.gov

2017-03-22

Adult Anaplastic (Malignant) Meningioma; Adult Anaplastic Astrocytoma; Adult Anaplastic Ependymoma; Adult Anaplastic Oligodendroglioma; Adult Brain Stem Glioma; Adult Choroid Plexus Neoplasm; Adult Diffuse Astrocytoma; Adult Ependymoblastoma; Adult Ependymoma; Adult Giant Cell Glioblastoma; Adult Glioblastoma; Adult Gliosarcoma; Adult Grade II Meningioma; Adult Medulloblastoma; Adult Mixed Glioma; Adult Oligodendroglioma; Adult Papillary Meningioma; Adult Pineal Gland Astrocytoma; Adult Pineoblastoma; Adult Primary Melanocytic Lesion of Meninges; Adult Supratentorial Primitive Neuroectodermal Tumor; Malignant Adult Intracranial Hemangiopericytoma; Metastatic Malignant Neoplasm in the Brain; Multiple Sclerosis; Recurrent Adult Brain Neoplasm

Near-field photothermal microspectroscopy for adult stem-cell identification and characterization.

PubMed

Grude, Olaug; Hammiche, Azzedine; Pollock, Hubert; Bentley, Adam J; Walsh, Michael J; Martin, Francis L; Fullwood, Nigel J

2007-12-01

The identification of stem cells in adult tissue is a challenging problem in biomedicine. Currently, stem cells are identified by individual epitopes, which are generally tissue specific. The discovery of a stem-cell marker common to other adult tissue types could open avenues in the development of therapeutic stem-cell strategies. We report the use of the novel technique of Fourier transform infrared near-field photothermal microspectroscopy (FTIR-PTMS) for the characterization of stem cells, transit amplifying (TA) cells and terminally differentiated (TD) cells in the corneal epithelium. Principal component analysis (PCA) data demonstrate excellent discrimination of cell type by spectra. PCA in combination with linear discriminant analysis (PCA-LDA) shows that FTIR-PTMS very effectively discriminates between the three cell populations. Statistically significant differences above the 99% confidence level between IR spectra from stem cells and TA cells suggest that nucleic acid conformational changes are an important component of the differences between spectral data from the two cell types. FTIR-PTMS is a new addition to existing spectroscopy methods based on the concept of interfacing a conventional FTIR spectrometer with an atomic force microscope equipped with a near-field thermal sensing probe. FTIR-PTMS spectroscopy currently has spatial resolution that is similar to that of diffraction-limited optical detection FTIR spectroscopy techniques, but as a near-field probing technique has considerable potential for further improvement. Our work also suggests that FTIR-PTMS is potentially more sensitive than synchrotron radiation FTIR spectroscopy for some applications. Microspectroscopy techniques like FTIR-PTMS provide information about the entire molecular composition of cells, in contrast to epitope recognition that only considers the presence or absence of individual molecules. Our results with FTIR-PTMS on corneal stem cells are promising for the potential

Aqueous humor tyrosinase activity is indicative of iris melanocyte toxicity.

PubMed

Mahanty, Sarmistha; Kawali, Ankush A; Dakappa, Shruthi Shirur; Mahendradas, Padmamalini; Kurian, Mathew; Kharbanda, Varun; Shetty, Rohit; Setty, Subba Rao Gangi

2017-09-01

Antibiotics such as fluoroquinolones (FQLs) are commonly used to treat ocular infections but are also known to cause dermal melanocyte toxicity. The release of dispersed pigments from the iris into the aqueous humor has been considered a possible ocular side effect of the systemic administration of FQLs such as Moxifloxacin, and this condition is known as bilateral acute iris transillumination (BAIT). Bilateral acute depigmentation of iris (BADI) is a similar condition, with iris pigment released into the aqueous, but it has not been reported as a side effect of FQL. Iris pigments are synthesized by the melanogenic enzyme tyrosinase (TYR) and can be detected but not quantified by using slit-lamp biomicroscopy. The correlation between dispersed pigments in the aqueous and the extent of melanocyte toxicity due to topical antibiotics in vivo is not well studied. Here, we aimed to study the effect of topical FQLs on iris tissue, the pigment release in the aqueous humor and the development of clinically evident iris atrophic changes. We evaluated this process by measuring the activity of TYR in the aqueous humor of 82 healthy eyes undergoing cataract surgery following topical application of FQLs such as Moxifloxacin (27 eyes, preservative-free) or Ciprofloxacin (29 eyes, with preservative) or the application of non-FQL Tobramycin (26 eyes, with preservative) as a control. In addition, the patients were questioned and examined for ocular side effects in pre- and post-operative periods. Our data showed a significantly higher mean TYR activity in the aqueous humor of Ciprofloxacin-treated eyes compared to Moxifloxacin- (preservative free, p < 0.0001) or Tobramycin-treated eyes (p < 0.0001), which indicated that few quinolones under certain conditions are toxic to the iris melanocytes. However, the reduced TYR activity in the aqueous of Moxifloxacin-treated eyes was possibly due to the presence of a higher drug concentration, which inhibits TYR activity. Consistently

Automatic Classification of Specific Melanocytic Lesions Using Artificial Intelligence

PubMed Central

Jaworek-Korjakowska, Joanna; Kłeczek, Paweł

2016-01-01

Background. Given its propensity to metastasize, and lack of effective therapies for most patients with advanced disease, early detection of melanoma is a clinical imperative. Different computer-aided diagnosis (CAD) systems have been proposed to increase the specificity and sensitivity of melanoma detection. Although such computer programs are developed for different diagnostic algorithms, to the best of our knowledge, a system to classify different melanocytic lesions has not been proposed yet. Method. In this research we present a new approach to the classification of melanocytic lesions. This work is focused not only on categorization of skin lesions as benign or malignant but also on specifying the exact type of a skin lesion including melanoma, Clark nevus, Spitz/Reed nevus, and blue nevus. The proposed automatic algorithm contains the following steps: image enhancement, lesion segmentation, feature extraction, and selection as well as classification. Results. The algorithm has been tested on 300 dermoscopic images and achieved accuracy of 92% indicating that the proposed approach classified most of the melanocytic lesions correctly. Conclusions. A proposed system can not only help to precisely diagnose the type of the skin mole but also decrease the amount of biopsies and reduce the morbidity related to skin lesion excision. PMID:26885520

Molecular pathogenesis of malignant melanoma: a different perspective from the studies of melanocytic nevus and acral melanoma.

PubMed

Takata, Minoru; Murata, Hiroshi; Saida, Toshiaki

2010-02-01

The Clark model for melanoma progression emphasizes a series of histopathological changes beginning from benign melanocytic nevus to melanoma via dysplastic nevus. Several models of the genetic basis of melanoma development and progression are based on this Clark's multi-step model, and predict that the acquisition of a BRAF mutation can be a founder event in melanocytic neoplasia. However, our recent investigations have challenged this view, showing the polyclonality of BRAF mutations in melanocytic nevi. Furthermore, it is suggested that many melanomas, including acral and mucosal melanomas, arise de novo, not from melanocytic nevus. While mutations of the BRAF gene are frequent in melanomas on non-chronic sun damaged skin which are prevalent in Caucasians, acral and mucosal melanomas harbor mutations of the KIT gene as well as the amplifications of cyclin D1 or cyclin-dependent kinase 4 gene. Amplifications of the cyclin D1 gene are detected in normal-looking 'field melanocytes', which represent a latent progression phase of acral melanoma that precedes the stage of atypical melanocyte proliferation in the epidermis. Based on these observations, we propose an alternative genetic progression model for melanoma.

The Adult Drosophila Malpighian Tubules Are Maintained by Pluripotent Stem Cells

PubMed Central

Singh, Shree Ram; Liu, Wei; Hou, Steven X.

2007-01-01

Summary All animals must excrete the waste products of metabolism. Excretion is performed by the kidney in vertebrates and by the Malpighian tubules in Drosophila. The mammalian kidney has an inherent ability for recovery and regeneration following ischemic injury. Stem cells and progenitor cells have been proposed to be responsible for repair and regeneration of injured renal tissue. In Drosophila, the Malpighian tubules are thought to be very stable, and no stem cells have been identified. We have identified pluripotent stem cells in the region of lower tubules and ureters of the Malpighian tubules. Using lineage tracing and molecular marker labeling, we demonstrated that several differentiated cells in the Malpighian tubules arise from the stem cells and an autocrine JAK-STAT signaling regulates the stem cells' self-renewal. Identifying adult kidney stem cells in Drosophila may provide important clues for understanding mammalian kidney repair and regeneration during injury. PMID:18371350

The next generation of melanocyte data: Genetic, epigenetic, and transcriptional resource datasets and analysis tools.

PubMed

Loftus, Stacie K

2018-05-01

The number of melanocyte- and melanoma-derived next generation sequence genome-scale datasets have rapidly expanded over the past several years. This resource guide provides a summary of publicly available sources of melanocyte cell derived whole genome, exome, mRNA and miRNA transcriptome, chromatin accessibility and epigenetic datasets. Also highlighted are bioinformatic resources and tools for visualization and data queries which allow researchers a genome-scale view of the melanocyte. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

A reporter mouse model for in vivo tracing and in vitro molecular studies of melanocytic lineage cells and their diseases.

PubMed

Crawford, Melissa; Leclerc, Valerie; Dagnino, Lina

2017-08-15

Alterations in melanocytic lineage cells give rise to a plethora of distinct human diseases, including neurocristopathies, cutaneous pigmentation disorders, loss of vision and hearing, and melanoma. Understanding the ontogeny and biology of melanocytic cells, as well as how they interact with their surrounding environment, are key steps in the development of therapies for diseases that involve this cell lineage. Efforts to culture and characterize primary melanocytes from normal or genetically engineered mouse models have at times yielded contrasting observations. This is due, in part, to differences in the conditions used to isolate, purify and culture these cells in individual studies. By breeding ROSA mT/mG and Tyr::CreER T2 mice, we generated animals in which melanocytic lineage cells are identified through expression of green fluorescent protein. We also used defined conditions to systematically investigate the proliferation and migration responses of primary melanocytes on various extracellular matrix (ECM) substrates. Under our culture conditions, mouse melanocytes exhibit doubling times in the range of 10 days, and retain exponential proliferative capacity for 50-60 days. In culture, these melanocytes showed distinct responses to different ECM substrates. Specifically, laminin-332 promoted cell spreading, formation of dendrites, random motility and directional migration. In contrast, low or intermediate concentrations of collagen I promoted adhesion and acquisition of a bipolar morphology, and interfered with melanocyte forward movements. Our systematic evaluation of primary melanocyte responses emphasizes the importance of clearly defining culture conditions for these cells. This, in turn, is essential for the interpretation of melanocyte responses to extracellular cues and to understand the molecular basis of disorders involving the melanocytic cell lineage. © 2017. Published by The Company of Biologists Ltd.

l-tyrosine induces melanocyte differentiation in novel pink-eyed dilution castaneus mouse mutant showing age-related pigmentation.

PubMed

Hirobe, Tomohisa; Ishikawa, Akira

2015-12-01

The mouse pink-eyed dilution (oculocutaneous albinism II; p/Oca2(p)) locus is known to control tyrosinase activity, melanin content, and melanosome development in melanocytes. Pink-eyed dilution castaneus (p(cas)/Oca2(p-cas)) is a novel mutant allele on mouse chromosome 7 that arose spontaneously in Indonesian wild mice, Mus musculus castaneus. Mice homozygous for Oca2(p-cas) usually exhibit pink eyes and beige-colored coat on nonagouti C57BL/6 (B6) background. Recently, a novel spontaneous mutation occurred in the progeny between this mutant and B6 mice. The eyes of this novel mutant progressively become black from pink and the coat becomes dark gray from beige with aging. The aim of this study is to clarify whatever differences exist in melanocyte proliferation and differentiation between the ordinary (pink-eyed) and novel (black-eyed) mutant using serum-free primary culture system. The characteristics of melanocyte proliferation and differentiation were investigated by serum-free primary culture system using melanocyte-proliferation medium (MDMD). The proliferation of melanoblasts in MDMD did not differ between the two mice. However, when the epidermal cell suspensions were cultured with MDMD supplemented with l-tyrosine (Tyr), the differentiation of black-eyed melanocytes was greatly induced in a concentration-dependent manner compared with pink-eyed melanocytes. Immunocytochemistry demonstrated that the expression of tyrosinase and tyrosinase-related protein-1 (Tyrp1) was greatly induced or stimulated both in pink-eyed and black-eyed melanocytes, whereas the expression of microphthalmia-associated transcription factor (Mitf) was stimulated only in black-eyed melanocytes. These results suggest that the age-related coat darkening in black-eyed mutant may be caused by the increased ability of melanocyte differentiation dependent on l-Tyr through the upregulation of tyrosinase, Tyrp1, and Mitf. This mutant mouse may be useful for animal model to clarify the

Image enhancement of optical images for binary system of melanocytes and keratinocytes

NASA Astrophysics Data System (ADS)

Takanezawa, S.; Baba, A.; Sako, Y.; Ozaki, Y.; Date, A.; Toyama, K.; Morita, S.

2013-05-01

Automatic determination of the cell shapes of large numbers of melanocytes based on optical images of human skin models have been largely unsuccessful (the complexities introduced by dendrites and the melanin pigmentation over the keratinocytes to give unclear outlines). Here, we present an image enhancement procedure for enhancing the contrast of images with removing the non-uniformity of background. The brightness is normalized also for the non-uniform population density of melanocytes.

Effect of norfloxacin and moxifloxacin on melanin synthesis and antioxidant enzymes activity in normal human melanocytes.

PubMed

Beberok, Artur; Wrześniok, Dorota; Otręba, Michał; Miliński, Maciej; Rok, Jakub; Buszman, Ewa

2015-03-01

Fluoroquinolone antibiotics provide broad-spectrum coverage for a number of infectious diseases, including respiratory as well as urinary tract infections. One of the important adverse effects of these drugs is phototoxicity which introduces a serious limitation to their use. To gain insight the molecular mechanisms underlying the fluoroquinolones-induced phototoxic side effects, the impact of two fluoroquinolone derivatives with different phototoxic potential, norfloxacin and moxifloxacin, on melanogenesis and antioxidant enzymes activity in normal human melanocytes HEMa-LP was determined. Both drugs induced concentration-dependent loss in melanocytes viability. The value of EC50 for these drugs was found to be 0.5 mM. Norfloxacin and moxifloxacin suppressed melanin biosynthesis; antibiotics were shown to inhibit cellular tyrosinase activity and to reduce melanin content in melanocytes. When comparing the both analyzed fluoroquinolones, it was observed that norfloxacin possesses greater inhibitory effect on tyrosinase activity in melanocytes than moxifloxacin. The extent of oxidative stress in cells was assessed by measuring the activity of antioxidant enzymes: SOD, CAT, and GPx. It was observed that norfloxacin caused higher depletion of antioxidant status in melanocytes when compared with moxifloxacin. The obtained results give a new insight into the mechanisms of fluoroquinolones toxicity directed to pigmented tissues. Moreover, the presented differences in modulation of biochemical processes in melanocytes may be an explanation for various phototoxic activities of the analyzed fluoroquinolone derivatives in vivo.

Empowering Adult Stem Cells for Myocardial Regeneration V2.0: Success in Small Steps

PubMed Central

Broughton, Kathleen; Sussman, Mark A.

2016-01-01

Much has changed since our survey of the landscape for myocardial regeneration powered by adult stem cells four years ago (Mohsin et al., Empowering adult stem cells for myocardial regeneration. Circ Res. 2011; 109(12):1415–1428) [1]. The intervening years since that first review has witnessed an explosive expansion of studies that advance both understanding and implementation of adult stem cells in promoting myocardial repair. Painstaking research from innumerable laboratories throughout the world is prying open doors that may lead to restoration of myocardial structure and function in the wake of pathologic injury. This global effort has produced deeper mechanistic comprehension coupled with an evolving appreciation for the complexity of myocardial regeneration in the adult context. Undaunted by both known and (as yet) unknown challenges, pursuit of myocardial regenerative medicine mediated by adult stem cell therapy has gathered momentum fueled by tantalizing clues and visionary goals. This concise review takes a somewhat different perspective than our initial treatise, taking stock of the business sector that has become an integral part of the field while concurrently updating “state of affairs” in cutting edge research. Looking retrospectively at advancement over the years as all reviews eventually must, the fundamental lesson to be learned is best explained by Jonatan Mårtensson: “Success will never be a big step in the future. Success is a small step taken just now.” PMID:26941423

Organ culture of mammalian skin and the effects of ultraviolet light and testosterone on melanocyte morphology and function

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glimcher, M.E.; Garcia, R.I.; Szab'o, G.

1978-05-01

Scrotal skin of black Long-Evans rats and human thigh skin were maintained in vitro as organ cultures for as long as 14 days, and examined histologically using the combined skin splitting and Dopa techniques. Selected rat skin cultures received testosterone in the culture medium and/or were irradiated with ultraviolet light (290 to 320 nm uvl). With increased time in culture, scrotal melanocytes round up and there is an increase in epidermal pigmentation. Human skin behaves similarly; after eight days in vitro human melanocytes also become rounded, but remain strongly Dopa-positive. Addition of exogenous testosterone to cultured rat skin maintains dendriticmore » morphology of melanocytes, but cell body size is still reduced. uvl irradiation stimulates melanocytes in rat skin cultures, maintaining their dendritic morphology and increasing epidermal and dermal pigmentation. Cultured skin receiving both uvl and testosterone illustrates a synergistic effect. Electron microscopic examination of cultured rat skin shows the presence of large melanosome complexes in keratinocytes, much larger than those found in vivo. Melanocytes appear to be active as they contain an extensive Golgi zone, rough endoplasmic reticulum, and melanosomes in various stages of formation. Dermis contained many dermal melanocytes and macrophages laden with melanosomes, correlating with the increased visible dermal pigmentation in vitro. This uvl stimulation of melanocytes in our skin organ cultures contrasts with the lack of melanogenic stimulation found in melanoma cell cultures. Our findings suggest that the intact epidermal melanin unit may be necessary for uvl stimulation of melanocytes.« less

UV exposure, genetic targets in melanocytic tumors and transgenic mouse models.

PubMed

de Gruijl, Frank R; van Kranen, Henk J; van Schanke, Arne

2005-01-01

The genetic changes and corruption of kinase activity in melanomas appear to revolve around a central axis: mitogenic signaling along the RAS pathway down to transcription regulation by pRB. Epidemiological studies point to the importance of ultraviolet (UV) radiation in the etiology of melanoma, but where and how UV radiation is targeted to contribute to the oncogenic signaling remains obscure. Animal models of melanoma genesis could serve to clarify this issue, but many of these models are not responsive to UV exposure. Most interesting advances have been made by using transgenic mice that carry genetic defects that are known to be relevant to human melanoma: specifically, dysfunction in the tumor suppressive action of p16INK4a or a receptor tyrosine kinase/RAS pathway, that is constitutively activated in melanocytes. The latter types of mice appear to be most responsive to (neonatal) UV exposure. Whether this is due to a general increase in target cells by melanocytosis and a paucity or complete lack of pigment, or a possible UV-induced response of the promoter-enhancer of the transgene or a genuinely independent and additional genetic alteration caused by UV exposure needs to be established. Importantly, the full effect of UV radiation needs to be ascertained in mice with different pigmentation by varying the wavelengths, UV-B versus UV-A1, and the exposure schedules, i.e. neonatal versus adult and chronic versus intermittent overexposure. Intermittent UV-B overexposure deserves special attention because it most strongly evokes proliferative responses in melanocytes.

The nuclear factor (erythroid-derived 2)-like 2 (NRF2) antioxidant response promotes melanocyte viability and reduces toxicity of the vitiligo-inducing phenol monobenzone.

PubMed

Arowojolu, Omotayo A; Orlow, Seth J; Elbuluk, Nada; Manga, Prashiela

2017-07-01

Vitiligo, characterised by progressive melanocyte death, can be initiated by exposure to vitiligo-inducing phenols (VIPs). VIPs generate oxidative stress in melanocytes and activate the master antioxidant regulator NRF2. While NRF2-regulated antioxidants are reported to protect melanocytes from oxidative stress, the role of NRF2 in the melanocyte response to monobenzone, a clinically relevant VIP, has not been characterised. We hypothesised that activation of NRF2 may protect melanocytes from monobenzone-induced toxicity. We observed that knockdown of NRF2 or NRF2-regulated antioxidants NQO1 and PRDX6 reduced melanocyte viability, but not viability of keratinocytes and fibroblasts, suggesting that melanocytes were preferentially dependent upon NRF2 activity for growth compared to other cutaneous cells. Furthermore, melanocytes activated the NRF2 response following monobenzone exposure and constitutive NRF2 activation reduced monobenzone toxicity, supporting NRF2's role in the melanocyte stress response. In contrast, melanocytes from individuals with vitiligo (vitiligo melanocytes) did not activate the NRF2 response as efficiently. Dimethyl fumarate-mediated NRF2 activation protected normal and vitiligo melanocytes against monobenzone-induced toxicity. Given the contribution of oxidant-antioxidant imbalance in vitiligo, modulation of this pathway may be of therapeutic interest. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Ultraviolet radiation directly induces pigment production by cultured human melanocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Friedmann, P.S.; Gilchrest, B.A.

1987-10-01

In humans the major stimulus for cutaneous pigmentation is ultraviolet radiation (UVR). Little is known about the mechanism underlying this response, in part because of the complexity of interactions in whole epidermis. Using a recently developed culture system, human melanocytes were exposed daily to a physiologic range of UVR doses from a solar simulator. Responses were determined 24 hours after the last exposure. There was a dose-related increase in melanin content per cell and uptake of /sup 14/C-DOPA, accompanied by growth inhibition. Cells from donors of different racial origin gave proportionately similar increases in melanin, although there were approximately tenfoldmore » differences in basal values. Light and electron microscopy revealed UVR-stimulated increases in dendricity as well as melanosome number and degree of melanization, analogous to the well-recognized melanocyte changes following sun exposure of intact skin. Similar responses were seen with Cloudman S91 melanoma cells, although this murine cell line required lower UVR dosages and fewer exposures for maximal stimulation. These data establish that UVR is capable of directly stimulating melanogenesis. Because cyclic AMP elevation has been associated in some settings with increased pigment production by cultured melanocytes, preliminary experiments were conducted to see if the effects of UVR were mediated by cAMP. Both alpha-MSH and isobutylmethylxanthine (IBMX), as positive controls, caused a fourfold increase in cAMP level in human melanocytes and/or S91 cells, but following a dose of UVR sufficient to stimulate pigment production there was no change in cAMP level up to 4 hours after exposure. Thus, it appears that the UVR-induced melanogenesis is mediated by cAMP-independent mechanisms.« less

Correlation between melanogenic and catalase activity in in vitro human melanocytes: a synergic strategy against oxidative stress.

PubMed

Maresca, Vittoria; Flori, Enrica; Briganti, Stefania; Mastrofrancesco, Arianna; Fabbri, Claudia; Mileo, Anna M; Paggi, Marco G; Picardo, Mauro

2008-04-01

UV-induced DNA damage can lead to melanoma, the most dangerous form of skin cancer. Understanding the mechanisms employed by melanocytes to protect against UV is therefore a key issue. In melanocytes, catalase is the main enzyme responsible for degrading hydrogen peroxide and we have previously shown that that low basal levels of catalase activity are associated with the light phototype in in vitro and ex vivo models. Here we investigate the possible correlation between its activity and melanogenesis in primary cultures of human melanocytes. We show that while the total melanin concentration is directly correlated to the level of pigmentation, the more the degree of pigmentation increased, the lower the proportion of pheomelanin present. Moreover, in human melanocytes in vitro, catalase-specific mRNA, protein and enzymatic activity were all directly correlated with total cellular melanin content. We also observed that immediately after a peroxidative treatment, the increase in reactive oxygen species was inversely associated with pigmentation level. Darkly pigmented melanocytes therefore possess two protective strategies represented by melanins and catalase activity that are likely to act synergistically to counteract the deleterious effects of UV radiation. By contrast, lightly pigmented melanocytes possess lower levels of melanogenic and catalase activity and are therefore more susceptible to accumulate damage after UV exposition.

Tissue expansion in the treatment of giant congenital melanocytic nevi of the upper extremity

PubMed Central

Ma, Tengxiao; Fan, Ke; Li, Lei; Xie, Feng; Li, Hao; Chou, Haiyan; Zhang, Zhengwen

2017-01-01

Abstract The aim of our study was to use tissue expansion for the treatment of giant congenital melanocytic nevi of the upper extremity and examine potential advantages over traditional techniques. There were 3 stages in the treatment of giant congenital melanocytic nevi of the upper extremities using tissue expansion: first, the expander was inserted into the subcutaneous pocket; second, the expander was removed, lesions were excised, and the wound of the upper extremity was placed into the pocket to delay healing; third, the residual lesion was excised and the pedicle was removed. The pedicle flap was then unfolded to resurface the wound. During the period between June 2007 and December 2015, there were 11 patients with giant congenital melanocytic nevi of the upper extremities who underwent reconstruction at our department with skin expansion. Few complications were noted in each stage of treatment. The functional and aesthetic results were observed and discussed in this study. Optimal aesthetic and functional results were obtained using tissue expansion to reconstruct the upper extremities due to the giant congenital melanocytic nevi. PMID:28353563

Physicochemical Control of Adult Stem Cell Differentiation: Shedding Light on Potential Molecular Mechanisms

DTIC Science & Technology

2010-01-01

stem - cell -based biomedical and therapeutic applications, including tissue engineering, requires an understanding of the cell-cell and cell-environment interactions. To this end, recent efforts have been focused on the manipulation of adult stem cell differentiation using inductive soluble factors, designing suitable mechanical environments, and applying noninvasive physical forces. Although each of these different approaches has been successfully applied to regulate stem cell differentiation, it would be of great interest and

The effect of ultraviolet radiation on choroidal melanocytes and melanoma cell lines: cell survival and matrix metalloproteinase production.

PubMed

Lai, Kenneth; Di Girolamo, Nick; Conway, Robert M; Jager, Martine J; Madigan, Michele C

2007-05-01

Ultraviolet radiation (UVR) can induce DNA damage and regulate the expression of factors important for tumour growth and metastasis, including matrix metalloproteinases (MMPs). Epidemiological studies suggest that chronic UVR exposure, especially during early adulthood, may be a risk factor in patients with choroidal melanoma. However, the effects of UV(R)-B on human choroidal melanocyte survival and growth are unknown. In this study, we investigated if UV(R)-B affected the in vitro survival, growth and MMP production of choroidal melanocytes and melanoma cells. Cultures of primary choroidal melanocytes and melanoma cell lines (OCM-1 and OCM-8) were exposed to UV(R)-B (0-30 mJ/cm(2)). The cell morphology and growth were examined, and cell viability was assessed using an MTT assay. Gelatin zymography was used to assess the enzymatic activity for MMP-2 and -9 in conditioned media following UV(R)-B treatment. UV(R)-B > or =20 mJ/cm(2) was cytotoxic for choroidal melanocytes. Cytotoxic doses of 5 to 10 mJ/cm(2) were found for OCM-8 and OCM-1 melanoma cell lines. Low levels of UV(R)-B (2.5 and 3.5 mJ/cm(2)) significantly reduced melanoma cell viability after 48 h, although melanocyte viability was not affected by doses of UV(R)-B <10 mJ/cm(2). Conditioned media from melanoma cells and melanocytes displayed pro-MMP-2 activity independent of UV(R)-B. Control and UV(R)-B-treated OCM-1 cells secreted active MMP-2 up to 72 h. Pro-MMP-9 activity was seen from 36 h for control and UV(R)-B-treated OCM-1 and OCM-8 cells. Melanocytes appeared more resistant to physiological doses of UV(R)-B than melanoma cells; the potential of melanocytes to initially survive DNA damage following UV(R)-B exposure may be relevant to the subsequent transformation of melanocytes to melanomas. Although UV(R)-B did not induce the production and/or activation of MMP-2 and -9 in melanocytes or melanoma cells, we are currently investigating whether DNA damage-response genes such as p53 and p21 can be

Mechanical properties of growing melanocytic nevi and the progression to melanoma

NASA Astrophysics Data System (ADS)

Taloni, Alessandro; Alemi, Alexander; Ciusani, Emilio; Sethna, James P.; Zapperi, Stefano; La Porta, Caterina A. M.; National Research Council Of Italy Team; Lassp, Department Of Physics, Cornell University Team; Istituto Neurologico Carlo Besta Collaboration; Department Of Biosciences, University Of Milano Team

2015-03-01

Melanocytic nevi are benign proliferations that sometimes turn into malignant melanoma in a way that is still unclear from the biochemical and genetic point of view. Diagnostic and prognostic tools are then mostly based on dermoscopic examination and morphological analysis of histological tissues. To investigate the role of mechanics and geometry in the morpholgical dynamics of melanocytic nevi, we present a computational model for cell proliferation in a layered non-linear elastic tissue. Our simulations show that the morphology of the nevus is correlated to the initial location of the proliferating cell starting the growth process and to the mechanical properties of the tissue. We also demonstrate that melanocytes are subject to compressive stresses that fluctuate widely in the nevus and depend on the growth stage. Numerical simulations of cells in the epidermis releasing matrix metalloproteinases display an accelerated invasion of the dermis by destroying the basal membrane. Moreover, we show experimentally that osmotic stress and collagen inhibit growth in primary melanoma cells while the effect is much weaker in metastatic cells.

UVA phototransduction drives early melanin synthesis in human melanocytes.

PubMed

Wicks, Nadine L; Chan, Jason W; Najera, Julia A; Ciriello, Jonathan M; Oancea, Elena

2011-11-22

Exposure of human skin to solar ultraviolet radiation (UVR), a powerful carcinogen [1] comprising ~95% ultraviolet A (UVA) and ~5% ultraviolet B (UVB) at the Earth's surface, promotes melanin synthesis in epidermal melanocytes [2, 3], which protects skin from DNA damage [4, 5]. UVB causes DNA lesions [6] that lead to transcriptional activation of melanin-producing enzymes, resulting in delayed skin pigmentation within days [7]. In contrast, UVA causes primarily oxidative damage [8] and leads to immediate pigment darkening (IPD) within minutes, via an unknown mechanism [9, 10]. No receptor protein directly mediating phototransduction in skin has been identified. Here we demonstrate that exposure of primary human epidermal melanocytes (HEMs) to UVA causes calcium mobilization and early melanin synthesis. Calcium responses were abolished by treatment with G protein or phospholipase C (PLC) inhibitors or by depletion of intracellular calcium stores. We show that the visual photopigment rhodopsin [11] is expressed in HEMs and contributes to UVR phototransduction. Upon UVR exposure, significant melanin production was measured within one hour; cellular melanin continued to increase in a retinal- and calcium-dependent manner up to 5-fold after 24 hr. Our findings identify a novel UVA-sensitive signaling pathway in melanocytes that leads to calcium mobilization and melanin synthesis and may underlie the mechanism of IPD in human skin. Copyright © 2011 Elsevier Ltd. All rights reserved.

Conditioned Media from Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells Inhibits Melanogenesis by Promoting Proteasomal Degradation of MITF.

PubMed

Kim, Eun Sung; Jeon, Hong Bae; Lim, Hoon; Shin, Ji Hyun; Park, So Jung; Jo, Yoon Kyung; Oh, Wonil; Yang, Yoon Sun; Cho, Dong-Hyung; Kim, Ju-Yeon

2015-01-01

Human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) secrete various beneficial molecules, which have anti-apoptotic activity and cell proliferation. However, the effect of hUCB-MSCs in melanogenesis is largely unclear. In this study, we show that conditioned media (CM) derived from hUCB-MSCs inhibit melanogenesis by regulating microphthalmia-associated transcription factor (MITF) expression via the ERK signalling pathway. Treatment of hUCB-MSC-CM strongly inhibited the alpha-melanocyte stimulating hormone-induced hyperpigmentation in melanoma cells as well as melanocytes. Treatment of hUCB-MSC-CM induced ERK1/2 activation in melanocytes. In addition, inhibition of ERK1/2 suppressed the anti-pigmentation activity of the hUCB-MSC-CM in melanocytes and in vitro artificial skin models. We also found that the expression of MITF was appreciably diminished while expression of phosphorylated MITF, which leads to its proteasomal degradation, was increased in cells treated with hUCB-MSC-CM. These results suggested that hUCB-MSC-CM significantly suppresses melanin synthesis via MITF degradation by the ERK pathway activation.

Histomorphologic spectrum of BAP1 negative melanocytic neoplasms in a family with BAP1-associated cancer susceptibility syndrome.

PubMed

Marušić, Zlatko; Buljan, Marija; Busam, Klaus J

2015-06-01

Multiple BAP1 negative melanocytic neoplasms are a hallmark of familial cancer susceptibility syndrome caused by BAP1 germline mutation. The syndrome is characterized by increased incidence of renal cell carcinoma, mesothelioma, cholangiocarcinoma, cutaneous and uveal melanoma and some other neoplasms. We report histomorphologic characteristics of six cutaneous melanocytic neoplasms with loss of BAP1 expression in two members of a family with BAP1-associated cancer susceptibility syndrome. The neoplasms were dermal melanocytic nevi characterized by a proliferation of large epithelioid (spitzoid) melanocytes, and adipocytic metaplasia. Nuclear pseudoinclusions and multinucleated melanocytes were present in most neoplasms. In two of the cases, a nodular melanoma was found associated with a dermal nevus. None of the melanomas recurred or metastasized after 6 and 3 years of follow up. We report two new cases of melanoma arising in a BAP1-deficient melanocytic nevus in the setting of familial tumor predisposition syndrome. Adipocytic metaplasia and nuclear pseudoinclusions may be additional morphologic clues to a BAP1-deficient nevus. It remains to be seen whether these features are more common in familial than sporadic lesions. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

In vivo reflectance confocal microscopy imaging of melanocytic skin lesions: consensus terminology glossary and illustrative images.

PubMed

Scope, Alon; Benvenuto-Andrade, Cristiane; Agero, Anna-Liza C; Malvehy, Josep; Puig, Susana; Rajadhyaksha, Milind; Busam, Klaus J; Marra, Diego E; Torres, Abel; Propperova, Iva; Langley, Richard G; Marghoob, Ashfaq A; Pellacani, Giovanni; Seidenari, Stefania; Halpern, Allan C; Gonzalez, Salvador

2007-10-01

Reflectance confocal microscopy (RCM) has been used for over 10 years for in vivo skin imaging. However, to date no standard RCM terminology has been published. To establish a glossary of terms for RCM evaluation of melanocytic lesions. Prominent RCM researchers were presented with RCM images of melanocytic lesions. Reviewers evaluated RCM images for image quality, lesion architecture, and cellular details. Reviewers could utilize published descriptors or contribute unpublished terminology to describe lesion attributes. An online meeting was conducted to reach consensus that integrates and defines existing and new RCM descriptive terms. We present a glossary with descriptors of image quality, normal skin morphology, lesion architecture, and cellular details for RCM evaluation of melanocytic lesions. Usefulness of the glossary in RCM diagnosis of melanocytic lesions needs to be assessed. Standardization of terminology is important toward implementation of RCM in the clinical setting.

Typography manipulations can affect priming of word stem completion in older and younger adults.

PubMed

Gibson, J M; Brooks, J O; Friedman, L; Yesavage, J A

1993-12-01

The experiments reported here investigated whether changes of typography affected priming of word stem completion performance in older and younger adults. Across all experiments, the typeface in which a word appeared at presentation either did or did not match that of its 3-letter stem at test. In Experiment 1, no significant evidence of a typography effect was found when words were presented with a sentence judgment or letter judgment task. However, subsequent experiments revealed that, in both older and younger adults, only words presented with a syllable judgment task gave rise to the typography effect (Experiments 2-4). Specifically, performance was greater, when the presentation and test typeface matched than when they did not. Experiment 5, which used stem-cued recall, did not reveal a difference between syllable and letter judgment tasks. These findings highlight the complex nature of word stem completion performance.

Can adult neural stem cells create new brains? Plasticity in the adult mammalian neurogenic niches: realities and expectations in the era of regenerative biology.

PubMed

Kazanis, Ilias

2012-02-01

Since the first experimental reports showing the persistence of neurogenic activity in the adult mammalian brain, this field of neurosciences has expanded significantly. It is now widely accepted that neural stem and precursor cells survive during adulthood and are able to respond to various endogenous and exogenous cues by altering their proliferation and differentiation activity. Nevertheless, the pathway to therapeutic applications still seems to be long. This review attempts to summarize and revisit the available data regarding the plasticity potential of adult neural stem cells and of their normal microenvironment, the neurogenic niche. Recent data have demonstrated that adult neural stem cells retain a high level of pluripotency and that adult neurogenic systems can switch the balance between neurogenesis and gliogenesis and can generate a range of cell types with an efficiency that was not initially expected. Moreover, adult neural stem and precursor cells seem to be able to self-regulate their interaction with the microenvironment and even to contribute to its synthesis, altogether revealing a high level of plasticity potential. The next important step will be to elucidate the factors that limit this plasticity in vivo, and such a restrictive role for the microenvironment is discussed in more details.

RO4929097, Temozolomide, and Radiation Therapy in Treating Patients With Newly Diagnosed Malignant Glioma

ClinicalTrials.gov

2015-09-28

Acoustic Schwannoma; Adult Anaplastic (Malignant) Meningioma; Adult Anaplastic Astrocytoma; Adult Anaplastic Ependymoma; Adult Brain Stem Glioma; Adult Choroid Plexus Neoplasm; Adult Craniopharyngioma; Adult Diffuse Astrocytoma; Adult Ependymoblastoma; Adult Ependymoma; Adult Giant Cell Glioblastoma; Adult Glioblastoma; Adult Gliosarcoma; Adult Grade I Meningioma; Adult Grade II Meningioma; Adult Medulloblastoma; Adult Mixed Glioma; Adult Myxopapillary Ependymoma; Adult Oligodendroglioma; Adult Papillary Meningioma; Adult Pilocytic Astrocytoma; Adult Pineal Gland Astrocytoma; Adult Pineoblastoma; Adult Pineocytoma; Adult Primary Melanocytic Lesion of Meninges; Adult Subependymal Giant Cell Astrocytoma; Adult Subependymoma; Adult Supratentorial Primitive Neuroectodermal Tumor; Malignant Adult Intracranial Hemangiopericytoma

Imaging pigment chemistry in melanocytic conjunctival lesions with pump-probe microscopy

NASA Astrophysics Data System (ADS)

Wilson, Jesse W.; Vajzovic, Lejla; Robles, Francisco E.; Cummings, Thomas J.; Mruthyunjaya, Prithvi; Warren, Warren S.

2013-03-01

We extend nonlinear pump-probe microscopy, recently demonstrated to image the microscopic distribution of eumelanin and pheomelanin in unstained skin biopsy sections, to the case of melanocytic conjunctival lesions. The microscopic distribution of pigmentation chemistry serves as a functional indicator of melanocyte activity. In these conjunctival specimens (benign nevi, primary acquired melanoses, and conjunctival melanoma), we have observed pump-probe spectroscopic signatures of eumelanin, pheomelanin, hemoglobin, and surgical ink, in addition to important structural features that differentiate benign from malignant lesions. We will also discuss prospects for an in vivo `optical biopsy' to provide additional information before having to perform invasive procedures.

Adult subventricular zone neural stem cells as a potential source of dopaminergic replacement neurons

PubMed Central

Cave, John W.; Wang, Meng; Baker, Harriet

2014-01-01

Clinical trials engrafting human fetal ventral mesencephalic tissue have demonstrated, in principle, that cell replacement therapy provides substantial long-lasting improvement of motor impairments generated by Parkinson's Disease (PD). The use of fetal tissue is not practical for widespread clinical implementation of this therapy, but stem cells are a promising alternative source for obtaining replacement cells. The ideal stem cell source has yet to be established and, in this review, we discuss the potential of neural stem cells in the adult subventricular zone (SVZ) as an autologous source of replacement cells. We identify three key challenges for further developing this potential source of replacement cells: (1) improving survival of transplanted cells, (2) suppressing glial progenitor proliferation and survival, and (3) developing methods to efficiently produce dopaminergic neurons. Subventricular neural stem cells naturally produce a dopaminergic interneuron phenotype that has an apparent lack of vulnerability to PD-mediated degeneration. We also discuss whether olfactory bulb dopaminergic neurons derived from adult SVZ neural stem cells are a suitable source for cell replacement strategies. PMID:24574954

Substantial Effect of Melanin Influencing Factors on In vitro Melanogenesis in Muzzle Melanocytes of Differently Colored Hanwoo.

PubMed

Amna, Touseef; Park, Kyoung Mi; Cho, In-Kyung; Choi, Tae Jeong; Lee, Seung Soo; Seo, Kang-Seok; Hwang, Inho

2012-07-01

The present study was designed to investigate the effect of α-melanocyte-stimulating hormone (α-MSH), nitric oxide (NO) and L-cysteine on melanin production and expression of related genes MC1R, Tyr, Tyrp-1 and Tyrp-2 in muzzle melanocytes of differently colored three native Hanwoo cattle. Muzzle samples were taken from black, brindle and brown Hanwoo and purified melanocytes were cultured with α-MSH, nitric oxide and L-cysteine at 100 nM, 50 µM and 0.07 mg/ml of media respectively. The amounts of total melanin, eumelanin and mRNA expression at Tyr, Tyrp-1, Tyrp-2 and MC1R levels were quantified. α-MSH and nitric oxide significantly increased (p<0.05) the amount of total melanin in black and brindle whereas eumelanin production in brown Hanwoo muzzle melanocytes. On the contrary, L-cysteine greatly (p<0.05) depressed the eumelanin production in black color but increased in brown. Simultaneously, up regulation of Tyr by nitric oxide and α-MSH and down regulation of Tyr, Tyrp-2 and MC1R genes by L-cysteine were observed in muzzle melanocytes of all three phenotypes. The results of this study revealed nitric oxide and α-MSH contribute hyper-pigmentation by enhancing eumelanogenesis whereas L-cysteine contributes to pheomelanin production in different colored Hanwoo muzzle melanocytes.

Substantial Effect of Melanin Influencing Factors on In vitro Melanogenesis in Muzzle Melanocytes of Differently Colored Hanwoo

PubMed Central

Amna, Touseef; Park, Kyoung Mi; Cho, In-Kyung; Choi, Tae Jeong; Lee, Seung Soo; Seo, Kang-Seok; Hwang, Inho

2012-01-01

The present study was designed to investigate the effect of α-melanocyte-stimulating hormone (α-MSH), nitric oxide (NO) and L-cysteine on melanin production and expression of related genes MC1R, Tyr, Tyrp-1 and Tyrp-2 in muzzle melanocytes of differently colored three native Hanwoo cattle. Muzzle samples were taken from black, brindle and brown Hanwoo and purified melanocytes were cultured with α-MSH, nitric oxide and L-cysteine at 100 nM, 50 µM and 0.07 mg/ml of media respectively. The amounts of total melanin, eumelanin and mRNA expression at Tyr, Tyrp-1, Tyrp-2 and MC1R levels were quantified. α-MSH and nitric oxide significantly increased (p<0.05) the amount of total melanin in black and brindle whereas eumelanin production in brown Hanwoo muzzle melanocytes. On the contrary, L-cysteine greatly (p<0.05) depressed the eumelanin production in black color but increased in brown. Simultaneously, up regulation of Tyr by nitric oxide and α-MSH and down regulation of Tyr, Tyrp-2 and MC1R genes by L-cysteine were observed in muzzle melanocytes of all three phenotypes. The results of this study revealed nitric oxide and α-MSH contribute hyper-pigmentation by enhancing eumelanogenesis whereas L-cysteine contributes to pheomelanin production in different colored Hanwoo muzzle melanocytes. PMID:25049660

UVB induces atypical melanocytic lesions and melanoma in human skin.

PubMed Central

Atillasoy, E. S.; Seykora, J. T.; Soballe, P. W.; Elenitsas, R.; Nesbit, M.; Elder, D. E.; Montone, K. T.; Sauter, E.; Herlyn, M.

1998-01-01

A direct causal relationship between ultraviolet (UV) light in the B range and melanoma development has not been demonstrated in humans; this study aims to establish causality. A total of 158 RAG-1 mice, grafted with human newborn foreskin, were separated into four groups and observed for a median of 10 months: 1) no treatment, 2) a single treatment with 7,12-dimethyl(a)benzanthracene (DMBA), 3) UVB irradiation at 500 J/m2 alone, three times weekly, and 4) a combination of DMBA and UVB. Twenty-three percent of 40 normal human skin grafts treated with UVB only and 38% of 48 grafts treated with the combination of DMBA and UVB developed solar lentigines within 5 to 10 months of treatment. Melanocytic hyperplasia was found in 73% of all UVB-treated xenografts. Histological melanocytic changes resembling lentigo and lentigo maligna were seen in several skin grafts treated with both DMBA and UVB. In one graft of an animal treated with a combination of DMBA and UVB, a human malignant melanoma, nodular type, developed. This experimental system demonstrates that chronic UVB irradiation with or without an initiating carcinogen can induce human melanocytic lesions, including melanoma. Images Figure 2 Figure 3 Figure 4 Figure 5 PMID:9588887

Normal and tumoral melanocytes exhibit q-Gaussian random search patterns.

PubMed

da Silva, Priscila C A; Rosembach, Tiago V; Santos, Anésia A; Rocha, Márcio S; Martins, Marcelo L

2014-01-01

In multicellular organisms, cell motility is central in all morphogenetic processes, tissue maintenance, wound healing and immune surveillance. Hence, failures in its regulation potentiates numerous diseases. Here, cell migration assays on plastic 2D surfaces were performed using normal (Melan A) and tumoral (B16F10) murine melanocytes in random motility conditions. The trajectories of the centroids of the cell perimeters were tracked through time-lapse microscopy. The statistics of these trajectories was analyzed by building velocity and turn angle distributions, as well as velocity autocorrelations and the scaling of mean-squared displacements. We find that these cells exhibit a crossover from a normal to a super-diffusive motion without angular persistence at long time scales. Moreover, these melanocytes move with non-Gaussian velocity distributions. This major finding indicates that amongst those animal cells supposedly migrating through Lévy walks, some of them can instead perform q-Gaussian walks. Furthermore, our results reveal that B16F10 cells infected by mycoplasmas exhibit essentially the same diffusivity than their healthy counterparts. Finally, a q-Gaussian random walk model was proposed to account for these melanocytic migratory traits. Simulations based on this model correctly describe the crossover to super-diffusivity in the cell migration tracks.

Malignant melanocytic neoplasm of pancreas with liver metastasis: Is it malignant melanoma or clear cell sarcoma?

PubMed

Kodiatte, Thomas Alex; George, Sam Varghese; Chacko, Raju Titus; Ramakrishna, Banumathi

2017-01-01

Malignant melanocytic neoplasm, usually seen in soft tissues, is rare in a visceral location and presents as a diagnostic dilemma. We present a case of pancreatic malignant melanocytic neoplasm with liver metastasis. A 58-year-old man presented with left upper abdominal swelling and loss of appetite. Imaging revealed a large mass arising from the pancreatic tail, and this was diagnosed as malignant neoplasm with melanocytic differentiation on biopsy with the possible differentials of malignant melanoma, clear cell sarcoma (CCS), and perivascular epithelioid cell neoplasm. The patient underwent distal pancreatectomy and splenectomy for the same. Follow-up imaging 6 months later showed a metastatic liver lesion, for which he also underwent a liver resection. BRAF mutational analysis was found to be negative. Both CCS and malignant melanoma have similar morphological features and melanocytic differentiation, but each harbors a distinct genetic background. Differentiation of both has diagnostic and therapeutic implications.

Noncoherent-intense-pulsed light for the treatment of relapsing hairy intradermal melanocytic nevus after shave excision.

PubMed

Moreno-Arias, G A; Ferrando, J

2001-01-01

Few reports about melanocytic lesions treatment by means of noncoherent-intense-pulsed light (NCIPL) have been published. Here we evaluate the clinical results of a relapsing hairy intradermal melanocytic nevus treated with a noncoherent-intense-pulsed light source. A facial repigmented hairy intradermal melanocytic nevus that relapsed after shave excision, received four treatment sessions of a noncoherent-intense-pulsed light source (EpiLight, ESC Medical Systems Ltd, Israel) with the following parameters: 755 nm, a fluence energy of 40-42.5 J/cm(2), triple mode, a pulse width of 3.8 ms, and a delay of 20 ms, at 4-week intervals. Complete pigment clearance and hair removal was obtained. We have neither observed repigmentation nor hair regrowth after a 6 month-follow-up. No side effects were documented. Noncoherent-intense-pulse light is an effective treatment for hairy-pigmented melanocytic nevus. Copyright 2001 Wiley-Liss, Inc.

Regulatory System for Stem/Progenitor Cell Niches in the Adult Rodent Pituitary

PubMed Central

Yoshida, Saishu; Kato, Takako; Kato, Yukio

2016-01-01

The anterior lobe of the pituitary gland is a master endocrine tissue composed of five types of endocrine cells. Although the turnover rate of pituitary endocrine cells is as low as about 1.6% per day, recent studies have demonstrated that Sex-determining region Y-box 2 (SOX2)+-cells exist as pituitary stem/progenitor cells in the adult anterior lobe and contribute to cell regeneration. Notably, SOX2+-pituitary stem/progenitor cells form two types of niches in this tissue: the marginal cell layer (MCL-niche) and the dense cell clusters scattering in the parenchyma (parenchymal-niche). However, little is known about the mechanisms and factors for regulating the pituitary stem/progenitor cell niches, as well as the functional differences between the two types of niches. Elucidation of the regulatory mechanisms in the niches might enable us to understand the cell regeneration system that acts in accordance with physiological demands in the adult pituitary. In this review, so as to reveal the regulatory mechanisms of the two types of niche, we summarize the regulatory factors and their roles in the adult rodent pituitary niches by focusing on three components: soluble factors, cell surface proteins and extracellular matrixes. PMID:26761002

[Alpha-melanocyte-stimulating hormone. From bench to bedside].

PubMed

Böhm, M; Luger, T A

2010-06-01

Alpha-melanocyte-stimulating hormone (alpha-MSH) is a tridecapeptide that is produced by the skin itself from the precursor proopiomelanocortin. It crucially mediates ultraviolet light-induced tanning after binding to melanocortin-1 receptors (MC-1R) expressed on the surface of epidermal melanocytes. The potent pigment-inducing and also cytoprotective actions of alpha-MSH are the rationale for the performance of first phase II clinical trials with Nle4-D-Phe7-alpha-MSH (NDP-alpha-MSH), a subcutaneously administered synthetic and superpotent alpha-MSH analogue, in patients with photodermatoses such as erythropoietic protoporphyria. Since alpha-MSH has shown promising anti-inflammatory and antifibrotic properties in numerous preclinical studies, it will be most interesting to evaluate these effects in further clinical pilot studies with NDP-alpha-MSH. In addition to alpha-MSH analogues, truncated tripeptides such as KDPT which do not bind to MC-1R but have sustained anti-inflammatory properties are currently emerging as another novel therapeutic strategy in dermatology.

G2 accumulation and melanin overproduction in malignant melanocytes treated with a new nitrosourea.

PubMed

Buchdahl, C; Papon, J; Communal, Y; Bourges, M; Madelmont, J C

1998-12-01

Cystemustine (N'-(2-chloroethyl)-N-(2-(methylsulphonyl)ethyl)-N'-nitrosourea), a new anticancer chloroethylnitrosourea (CENU) is being tested in a phase II clinical trial of disseminated melanoma. The antitumour effect of this drug is mainly due to DNA damage in malignant melanocytes. Recently, we have shown that this damage can induce apoptosis in some melanoma cell lines. In others, apoptosis is not clearly observed, although there is a strong cytostatic effect. In this paper, we have characterized the cytological effect of cystemustine on murine malignant melanocytes (B16 cell line) which are resistant to apoptosis induced by this CENU. The results show that 3 days after cystemustine treatment, these melanocytes had accumulated in phase G2 of the cell cycle. There was then a strong morphological modification during a long cytostatic phase up to 30 days after treatment. During this cytostatic phase, there was uncontrolled DNA synthesis and marked swelling. Also, tyrosinase activity, melanin content and the number of mature melanosomes were greatly increased. These results suggest that when malignant melanocytes are not able to undergo apoptosis after treatment with CENU, they accumulate in G2 and this is followed by enhancement of melanogenesis.

UVB-irradiated keratinocytes induce melanoma-associated ganglioside GD3 synthase gene in melanocytes via secretion of tumor necrosis factor α and interleukin 6

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miyata, Maiko; Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065; Ichihara, Masatoshi

Highlights: • Melanocytes showed low ST8SIA1 and high B3GALT4 levels in contrast with melanomas. • Direct UVB irradiation of melanocytes did not induce ganglioside synthase genes. • Culture supernatants of UVB-irradiated keratinocytes induced ST8SIA1 in melanocytes. • TNFα and IL-6 secreted from keratinocytes enhanced ST8SIA1 expression in melanocytes. • Inflammatory cytokines induced melanoma-related ST8SIA1 in melanocytes. - Abstract: Although expression of gangliosides and their synthetic enzyme genes in malignant melanomas has been well studied, that in normal melanocytes has been scarcely analyzed. In particular, changes in expression levels of glycosyltransferase genes responsible for ganglioside synthesis during evolution of melanomas frommore » melanocytes are very important to understand roles of gangliosides in melanomas. Here, expression of glycosyltransferase genes related to the ganglioside synthesis was analyzed using RNAs from cultured melanocytes and melanoma cell lines. Quantitative RT-PCR revealed that melanomas expressed high levels of mRNA of GD3 synthase and GM2/GD2 synthase genes and low levels of GM1/GD1b synthase genes compared with melanocytes. As a representative exogenous stimulation, effects of ultraviolet B (UVB) on the expression levels of 3 major ganglioside synthase genes in melanocytes were analyzed. Although direct UVB irradiation of melanocytes caused no marked changes, culture supernatants of UVB-irradiated keratinocytes (HaCaT cells) induced definite up-regulation of GD3 synthase and GM2/GD2 synthase genes. Detailed examination of the supernatants revealed that inflammatory cytokines such as TNFα and IL-6 enhanced GD3 synthase gene expression. These results suggest that inflammatory cytokines secreted from UVB-irradiated keratinocytes induced melanoma-associated ganglioside synthase genes, proposing roles of skin microenvironment in the promotion of melanoma-like ganglioside profiles in melanocytes.« less

Neuronal differentiation of stem cells isolated from adult muscle.

PubMed

Romero-Ramos, Marina; Vourc'h, Patrick; Young, Henry E; Lucas, Paul A; Wu, Young; Chivatakarn, Onanong; Zaman, Rumina; Dunkelman, Noushin; el-Kalay, Mohammad A; Chesselet, Marie-Françoise

2002-09-15

Lineage uncommitted pluripotent stem cells reside in the connective tissue of skeletal muscle. The present study was carried out with pluripotent stem cells (PPSCs) isolated from 6-month old rat muscle. Before differentiation, these cells were vimentin+, CD90+, CD45-, and varied in their expression of CD34. The PPSCs were expanded as non-adherent aggregates under similar conditions to those used to generate neurospheres from embryonic or neural stem cells. The PPSC-derived neurospheres were positive for nestin, an early marker present in neuronal precursors, and expressed the two alternative mRNA forms of the neuroectodermal marker Pax-6, as well as mRNA for Oct-4, a gene related to the pluripotentiality of stem cells. To confirm their neural potential, PPSC-derived neurospheres were plated on coated coverslips under varying conditions: Neurobasal medium with N2 or B27, and either NT3 or BDNF. After 4-6 days the cells expressed neuronal (Tuj1+, NF68), astrocytic (GFAP) and oligodendrocytic (MOSP+, MBP+) markers, both by immunocytochemistry and RT-PCR. In addition, PPSCs were cultured as monolayers under adherent conditions, exposed to growth factors and defined differentiating conditions for 5 hr, and subsequently kept for 2 days in a maturation medium. At this point they gave rise to a mixed population of early neural progenitors (Nestin+ or NG2+), immature and mature neurons (Tuj1+ and NF145+) and myelin producing oligodendrocytes (CNPase + and MOSP+). Our study shows that PPSCs present in adult muscle can overcome germ lineage restrictions and express the molecular characteristics of brain cells. Therefore, PPSCs isolated from adult muscle could provide a novel source for autologous cell replacement in neurodegenerative and demyelinating diseases. Copyright 2002 Wiley-Liss, Inc.

Effects of low-dose γ-rays on the embryonic development of mouse melanoblasts and melanocytes in the epidermis and hair bulbs.

PubMed

Hirobe, Tomohisa; Eguchi-Kasai, Kiyomi; Sugaya, Kimihiko; Murakami, Masahiro

2011-06-01

The effects of low-dose γ-rays on the embryonic development of animal cells are not well studied. The mouse melanocyte is a good model to study the effects of low-dose γ-rays on the development of animal cells, as it possesses visible pigment (melanin) as a differentiation marker. The aim of this study is to investigate in detail the effects of low-dose γ-rays on embryonic development of mouse melanoblasts and melanocytes in the epidermis and hair bulbs at cellular level. Pregnant females of C57BL/10J mice at nine days of gestation were whole-body irradiated with a single acute dose of γrays (0.1, 0.25, 0.5, and 0.75 Gy), and the effects of γ-rays were studied by scoring changes in the development of epidermal melanoblasts and melanocytes, hair follicles, and hair bulb melanocytes at 18 days in gestation. The number of epidermal melanoblasts and melanocytes, hair follicles, and hair bulb melanocytes in the dorsal and ventral skins was markedly decreased even at 0.1 Gy-treated embryos (P < 0.001), and gradually decreased as dose increased. The effects on the ventral skin were greater than those on the dorsal skin. The dramatic reduction in the number of melanocytes compared to melanoblasts was observed in the ventral skin, but not in the dorsal skin. These results suggest that low-dose γ-rays provoke the death of melanoblasts and melanocytes, or inhibit the proliferation and differentiation of melanoblasts and melanocytes, even at the low dose.

Sema4D, the ligand for Plexin B1, suppresses c-Met activation and migration and promotes melanocyte survival and growth

PubMed Central

Soong, Joanne; Chen, Yulin; Shustef, Elina; Scott, Glynis

2011-01-01

Semaphorins are secreted and membrane bound proteins involved in neural pathfinding, organogenesis, and tumor progression, through Plexin and neuropilins receptors. We recently reported that Plexin B1, the Semaphorin 4D receptor, is a tumor suppressor protein for melanoma, in part, through inhibition of the oncogenic c-Met tyrosine kinase receptor. In this report we show that Sema4D is a protective paracrine factor for normal human melanocyte survival in response to ultraviolet irradiation, that it stimulates proliferation, and regulates the activity of the c-Met receptor. c-Met receptor signaling stimulates melanocyte migration, in part through down-regulation of the cell adhesion molecule E-cadherin. Sema4D suppressed activation of c-Met in response to its ligand hepatocyte growth factor (HGF), and partially blocked the suppressive effects of HGF on E-cadherin expression in melanocytes and HGF-dependent migration. These data demonstrate a role for Plexin B1 in maintenance of melanocyte survival and proliferation in the skin, and suggest that Semaphorin 4D and Plexin B1 act cooperatively with HGF and c-Met to regulate c-Met dependent effects in human melanocytes. Because our data show that Plexin B1 is profoundly down-regulated by UVB in melanocytes, loss of Plexin B1 may accentuate HGF dependent effects on melanocytes, including melanocyte migration. PMID:22189792

Sema4D, the ligand for Plexin B1, suppresses c-Met activation and migration and promotes melanocyte survival and growth.

PubMed

Soong, Joanne; Chen, Yulin; Shustef, Elina M; Scott, Glynis A

2012-04-01

Semaphorins are secreted and membrane-bound proteins involved in neural pathfinding, organogenesis, and tumor progression, through Plexin and neuropilin receptors. We recently reported that Plexin B1, the Semaphorin 4D (Sema4D) receptor, is a tumor-suppressor protein for melanoma, which functions, in part, through inhibition of the oncogenic c-Met tyrosine kinase receptor. In this report, we show that Sema4D is a protective paracrine factor for normal human melanocyte survival in response to UV irradiation, and that it stimulates proliferation and regulates the activity of the c-Met receptor. c-Met receptor signaling stimulates melanocyte migration, partly through downregulation of the cell adhesion molecule E-cadherin. Sema4D suppressed activation of c-Met in response to its ligand, hepatocyte growth factor (HGF), and partially blocked the suppressive effects of HGF on E-cadherin expression in melanocytes and HGF-dependent migration. These data demonstrate a role for Plexin B1 in maintenance of melanocyte survival and proliferation in the skin, and suggest that Sema4D and Plexin B1 act cooperatively with HGF and c-Met to regulate c-Met-dependent effects in human melanocytes. Because our data show that Plexin B1 is profoundly downregulated by UVB in melanocytes, loss of Plexin B1 may accentuate HGF-dependent effects on melanocytes, including melanocyte migration.

Origins of adult pigmentation: diversity in pigment stem cell lineages and implications for pattern evolution

PubMed Central

Spiewak, Jessica E.

2014-01-01

Summary Teleosts comprise about half of all vertebrate species and exhibit an extraordinary diversity of adult pigment patterns that function in shoaling, camouflage and mate choice and have played important roles in speciation. Here, we review recent studies that have identified several distinct neural crest lineages, with distinct genetic requirements, that give rise to adult pigment cells in fishes. These lineages include post-embryonic, peripheral nerve associated stem cells that generate black melanophores and iridescent iridophores, cells derived directly from embryonic neural crest cells that generate yellow-orange xanthophores, and bipotent stem cells that generate both melanophores and xanthophores. This complexity in adult chromatophore lineages has implications for our understanding of adult traits, melanoma, and the evolutionary diversification of pigment cell lineages and patterns. PMID:25421288

Adult murine CNS stem cells express aquaporin channels.

PubMed

La Porta, Caterina A M; Gena, Patrizia; Gritti, Angela; Fascio, Umberto; Svelto, Maria; Calamita, Giuseppe

2006-02-01

Fluid homoeostasis is of critical importance in many functions of the CNS (central nervous system) as indicated by the fact that dysregulation of cell volume underlies clinical conditions such as brain oedema and hypoxia. Water balance is also important during neurogenesis as neural stem cells move considerable amounts of water into or out of the cell to rapidly change their volume during differentiation. Consistent with the relevance of water transport in CNS, multiple AQP (aquaporin) water channels have been recognized and partially characterized in brain cell function. However, the presence and distribution of AQPs in CNS stem cells has not yet been assessed. In the present study, we investigate the expression and subcellular localization of AQPs in murine ANSCs (adult neural stem cells). Considerable AQP8 mRNAs were found in ANSCs where, as expected, the transcript of two additional AQPs, AQP4 and AQP9, was also detected. Immunoblotting with subcellular membrane fractions of ANSCs showed predominant expression of AQP8 in the mitochondria-enriched fraction. This result was consistent with the spotted immunoreactivity profile encountered within the ANSCs by confocal immunofluorescence. AQP8 may have a role in mitochondrial volume regulation during ANSC differentiation. Recognition of AQPs in ANSCs is a step forward in our knowledge of water homoeostasis in the CNS and provides useful information for the purposes of stem cell technology.

Molecular effects of 1-naphthyl-methylcarbamate and solar radiation exposures on human melanocytes.

PubMed

Ferrucio, Bianca; Tiago, Manoela; Fannin, Richard D; Liu, Liwen; Gerrish, Kevin; Maria-Engler, Silvya Stuchi; Paules, Richard S; Barros, Silvia Berlanga de Moraes

2017-02-01

Carbaryl (1-naphthyl-methylcarbamate), a broad-spectrum insecticide, has recently been associated with the development of cutaneous melanoma in an epidemiological cohort study with U.S. farm workers also exposed to ultraviolet radiation, the main etiologic factor for skin carcinogenesis. We hypothesized that carbaryl exposure may increase deleterious effects of UV solar radiation on skin melanocytes. This study aimed to characterize human melanocytes after individual or combined exposure to carbaryl (100μM) and solar radiation (375mJ/cm 2 ). In a microarray analysis, carbaryl, but not solar radiation, induced an oxidative stress response, evidenced by the upregulation of antioxidant genes, such as Hemeoxygenase-1 (HMOX1), and downregulation of Microphtalmia-associated Transcription Factor (MITF), the main regulator of melanocytic activity; results were confirmed by qRT-PCR. Carbaryl and solar radiation induced a gene response suggestive of DNA damage and cell cycle alteration. The expression of CDKN1A, BRCA1/2 and MDM2 genes was notably more intense in the combined treatment group, in a synergistic manner. Flow cytometry assays demonstrated S-phase cell cycle arrest, reduced apoptosis levels and faster induction of cyclobutane pyrimidine dimers (CPD) lesions in carbaryl treated groups. Our data suggests that carbaryl is genotoxic to human melanocytes, especially when associated with solar radiation. Copyright © 2016 Elsevier B.V. All rights reserved.

Antimelanogenic Efficacy of Melasolv (3,4,5-Trimethoxycinnamate Thymol Ester) in Melanocytes and Three-Dimensional Human Skin Equivalent.

PubMed

Lee, John Hwan; Lee, Eun-Soo; Bae, Il-Hong; Hwang, Jeong-Ah; Kim, Se-Hwa; Kim, Dae-Yong; Park, Nok-Hyun; Rho, Ho Sik; Kim, Yong Jin; Oh, Seong-Geun; Lee, Chang Seok

2017-01-01

Excessive melanogenesis often causes unaesthetic hyperpigmentation. In a previous report, our group introduced a newly synthesized depigmentary agent, Melasolv™ (3,4,5-trimethoxycinnamate thymol ester). In this study, we demonstrated the significant whitening efficacy of Melasolv using various melanocytes and human skin equivalents as in vitro experimental systems. The depigmentary effect of Melasolv was tested in melan-a cells (immortalized normal murine melanocytes), α-melanocyte-stimulating hormone (α-MSH)-stimulated B16 murine melanoma cells, primary normal human melanocytes (NHMs), and human skin equivalent (MelanoDerm). The whitening efficacy of Melasolv was further demonstrated by photography, time-lapse microscopy, Fontana-Masson (F&M) staining, and 2-photon microscopy. Melasolv significantly inhibited melanogenesis in the melan-a and α-MSH-stimulated B16 cells. In human systems, Melasolv also clearly showed a whitening effect in NHMs and human skin equivalent, reflecting a decrease in melanin content. F&M staining and 2-photon microscopy revealed that Melasolv suppressed melanin transfer into multiple epidermal layers from melanocytes as well as melanin synthesis in human skin equivalent. Our study showed that Melasolv clearly exerts a whitening effect on various melanocytes and human skin equivalent. These results suggest the possibility that Melasolv can be used as a depigmentary agent to treat pigmentary disorders as well as an active ingredient in cosmetics to increase whitening efficacy. © 2017 S. Karger AG, Basel.

The gender differences in the inhibitory action of UVB-induced melanocyte activation by the administration of tranexamic acid.

PubMed

Hiramoto, Keiichi; Yamate, Yurika; Sugiyama, Daijiro; Takahashi, Yumi; Mafune, Eiichi

2016-05-01

Tranexamic acid has an inhibitory action on ultraviolet (UV) B-induced melanocyte activation. This study examined the sex differences in the inhibitory action of tranexamic acid on UVB-induced melanocyte activation. We irradiated the eye and ear of male and female mice with UVB at a dose of 1.0 kJ/m(2) using a 20SE sunlamp. We orally administered tranexamic acid (750 mg/kg/day) at 30 min before UVB exposure. Tranexamic acid inhibited the UVB-induced epidermal melanocyte activation, and the effect was more remarkable under UVB eye irradiation than under UVB ear irradiation. Furthermore, the melanocyte activity suppression effect was stronger in female mice than in male mice. Following the administration of tranexamic acid, the female displayed increased blood levels of β-endorphin and μ-opioid receptor and estradiol receptor β expression in comparison with the male. Furthermore, the effect of melanocyte activity suppression in the female mice was decreased by the administration of tamoxifen (antagonist of estrogen receptor) or naltrexone (antagonist of μ-opioid receptor). These results suggest that the suppression by tranexamic acid of the UVB-induced melanocyte activation (UVB sensitivity) is stronger in female mice than in male mice and that female hormones and β-endorphin play an important role in this sex difference. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A revisionist history of adult marrow stem cell biology or 'they forgot about the discard'.

PubMed

Quesenberry, P; Goldberg, L

2017-08-01

The adult marrow hematopoietic stem cell biology has largely been based on studies of highly purified stem cells. This is unfortunate because during the stem cell purification the great bulk of stem cells are discarded. These cells are actively proliferating. The final purified stem cell is dormant and not representative of the whole stem cell compartment. Thus, a large number of studies on the cellular characteristics, regulators and molecular details of stem cells have been carried on out of non-represented cells. Niche studies have largely pursued using these purified stem cells and these are largely un-interpretable. Other considerations include the distinction between baseline and transplant stem cells and the modulation of stem cell phenotype by extracellular vesicles, to cite a non-inclusive list. Work needs to proceed on characterizing the true stem cell population.

Differentiating intratumoral melanocytes from Langerhans cells in nonmelanocytic pigmented skin tumors in vivo by label-free third-harmonic generation microscopy

NASA Astrophysics Data System (ADS)

Weng, Wei-Hung; Liao, Yi-Hua; Tsai, Ming-Rung; Wei, Ming-Liang; Huang, Hsin-Yi; Sun, Chi-Kuang

2016-07-01

Morphology and distribution of melanocytes are critical imaging information for the diagnosis of melanocytic lesions. However, how to image intratumoral melanocytes noninvasively in pigmented skin tumors is seldom investigated. Third-harmonic generation (THG) is shown to be enhanced by melanin, whereas high accuracy has been demonstrated using THG microscopy for in vivo differential diagnosis of nonmelanocytic pigmented skin tumors. It is thus desirable to investigate if label-free THG microscopy was capable to in vivo identify intratumoral melanocytes. In this study, histopathological correlations of label-free THG images with the immunohistochemical images stained with human melanoma black (HMB)-45 and cluster of differentiation 1a (CD1a) were made. The correlation results indicated that the intratumoral THG-bright dendritic-cell-like signals were endogenously derived from melanocytes rather than Langerhans cells (LCs). The consistency between THG-bright dendritic-cell-like signals and HMB-45 melanocyte staining showed a kappa coefficient of 0.807, 84.6% sensitivity, and 95% specificity. In contrast, a kappa coefficient of -0.37, 21.7% sensitivity, and 30% specificity were noted between the THG-bright dendritic-cell-like signals and CD1a staining for LCs. Our study indicates the capability of noninvasive label-free THG microscopy to differentiate intratumoral melanocytes from LCs, which is not feasible in previous in vivo label-free clinical-imaging modalities.

Increases in Intracellular Zinc Enhance Proliferative Signaling as well as Mitochondrial and Endolysosomal Activity in Human Melanocytes.

PubMed

Rudolf, Emil; Rudolf, Kamil

2017-01-01

Zinc (Zn) is an important microelement required by skin cells for a variety of biological processes. The role of Zn in melanocyte proliferation and homeostasis has to date not been investigated. Human dermal melanocytes were isolated from patients and their proliferative activity determined along with both total and labile Zn content. Subsequently, changes in proliferation as well as in Zn content were determined upon exposure of the dermal melanocytes to external Zn. Further in-depth analyses were undertaken aimed at measuring the expression of proliferation-related proteins (determined by immunoblotting and densitometry), as well as changes in mitochondrial biogenesis and membrane potential (assessed by fluorescence-based cellometry) along with endolysosomal activity (determined by spectrofluorimetrically-measured elevation in fluorescence of lysosomal-aimed non-fuorescent substrate). Human skin melanocytes accumulate externally added Zn, a process which dose-dependently enhances their injury or proliferative activity. Enhanced proliferation is accompanied by an increased expression of the proteins AKT3, ERK1/2, c-MYC and CYCD. In addition, Zn-enriched melanocytes exhibit enhanced mitochondrial biogenesis, with individual mitochondria possessing stabilized mitochondrial membrane potential as well as showing elevated ATP and superoxide levels. Moreover, upon external exposure, Zn enters lysosomes/melanosomes, the activity of which is stimulated along with the process of autophagy. The determination of the unique Zn-dependent stimulation of melanocytes and in particular the enhancement of the cells' mitochondrial as well as lysosomal/melanosomal activities may prove important in tracing the sequence of steps in the process of melanomagenesis. © 2017 The Author(s). Published by S. Karger AG, Basel.

Evaluation of the Melanocytic Pathology Assessment Tool and Hierarchy for Diagnosis (MPATH-Dx) classification scheme for diagnosis of cutaneous melanocytic neoplasms: Results from the International Melanoma Pathology Study Group.

PubMed

Lott, Jason P; Elmore, Joann G; Zhao, Ge A; Knezevich, Stevan R; Frederick, Paul D; Reisch, Lisa M; Chu, Emily Y; Cook, Martin G; Duncan, Lyn M; Elenitsas, Rosalie; Gerami, Pedram; Landman, Gilles; Lowe, Lori; Messina, Jane L; Mihm, Martin C; van den Oord, Joost J; Rabkin, Michael S; Schmidt, Birgitta; Shea, Christopher R; Yun, Sook Jung; Xu, George X; Piepkorn, Michael W; Elder, David E; Barnhill, Raymond L

2016-08-01

Pathologists use diverse terminology when interpreting melanocytic neoplasms, potentially compromising quality of care. We sought to evaluate the Melanocytic Pathology Assessment Tool and Hierarchy for Diagnosis (MPATH-Dx) scheme, a 5-category classification system for melanocytic lesions. Participants (n = 16) of the 2013 International Melanoma Pathology Study Group Workshop provided independent case-level diagnoses and treatment suggestions for 48 melanocytic lesions. Individual diagnoses (including, when necessary, least and most severe diagnoses) were mapped to corresponding MPATH-Dx classes. Interrater agreement and correlation between MPATH-Dx categorization and treatment suggestions were evaluated. Most participants were board-certified dermatopathologists (n = 15), age 50 years or older (n = 12), male (n = 9), based in the United States (n = 11), and primary academic faculty (n = 14). Overall, participants generated 634 case-level diagnoses with treatment suggestions. Mean weighted kappa coefficients for diagnostic agreement after MPATH-Dx mapping (assuming least and most severe diagnoses, when necessary) were 0.70 (95% confidence interval 0.68-0.71) and 0.72 (95% confidence interval 0.71-0.73), respectively, whereas correlation between MPATH-Dx categorization and treatment suggestions was 0.91. This was a small sample size of experienced pathologists in a testing situation. Varying diagnostic nomenclature can be classified into a concise hierarchy using the MPATH-Dx scheme. Further research is needed to determine whether this classification system can facilitate diagnostic concordance in general pathology practice and improve patient care. Copyright © 2016 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

The effects of phototherapy and melanocytes on keratinocytes

PubMed Central

Tang, Luyan; Wu, Wenyu; Fu, Wenwen; Hu, Yao

2018-01-01

Phototherapy is widely used in the treatment of vitiligo. Previous studies have focused on the effects of ultraviolet (UV) radiation on melanocytes; however, the biological effects of phototherapy and melanocytes on keratinocytes remain to be elucidated. To investigate and assess the effects of clinically doses of broad band (BB)-UVA, narrow band (NB)-UVB and melanocytes on human keratinocytes in vitro, clinical doses of BB-UVA or NB-UVB radiation and human melanoma cell A375 co-culture were performed as stress divisors to HaCaT cells. Cell proliferation, expression of protease-activated receptor-2 (PAR-2) and nuclear factor E2-related factor 2 mRNA, lipid peroxidation and intracellular antioxidant level of keratinocytes were analyzed. It was demonstrated that UV radiation inhibited the proliferation of cells apart from following exposure to low dose (1 J/cm2) UVA. Medium dose (5 J/cm2) UVA radiation had no adverse effects on lipid peroxidation and increased antioxidant levels in HaCaT cells. Medium (200 mJ/cm2) and high (400 mJ/cm2) doses of UVB radiation induced cellular damage due to increased lipid peroxidation as indicated by levels of malondialdehyde. Furthermore, A375 co-culture treatment induced a similar effect on the lipid peroxidation of HaCaT as with low dose UVB radiation. Therefore, the results of the present study determined that clinical doses of BB-UVA and NB-UVB radiation had varying effects on proliferation and related protein levels in HaCaT cells. Co-culture with A375 had similar effects as those of low dose UVA and UVB radiation, in which the PAR-2 expression was significantly upregulated. PMID:29545869

THE MOLECULAR PATHOLOGY OF MELANOMA: AN INTEGRATED TAXONOMY OF MELANOCYTIC NEOPLASIA

PubMed Central

Bastian, Boris C.

2016-01-01

Melanomas are comprised of multiple biologically distinct categories, which differ in cell of origin, age of onset, clinical and histologic presentation, pattern of metastasis, ethnic distribution, causative role of UV radiation, predisposing germ line alterations, mutational processes, and patterns of somatic mutations. Neoplasms are initiated by gain of function mutations in one of several primary oncogenes, typically leading to benign melanocytic nevi with characteristic histologic features. The progression of nevi is restrained by multiple tumor suppressive mechanisms. Secondary genetic alterations override these barriers and promote intermediate or overtly malignant tumors along distinct progression trajectories. The current knowledge about pathogenesis, clinical, histological and genetic features of primary melanocytic neoplasms is reviewed and integrated into a taxonomic framework. PMID:24460190

Excitation-neurogenesis coupling in adult neural stem/progenitor cells.

PubMed

Deisseroth, Karl; Singla, Sheela; Toda, Hiroki; Monje, Michelle; Palmer, Theo D; Malenka, Robert C

2004-05-27

A wide variety of in vivo manipulations influence neurogenesis in the adult hippocampus. It is not known, however, if adult neural stem/progenitor cells (NPCs) can intrinsically sense excitatory neural activity and thereby implement a direct coupling between excitation and neurogenesis. Moreover, the theoretical significance of activity-dependent neurogenesis in hippocampal-type memory processing networks has not been explored. Here we demonstrate that excitatory stimuli act directly on adult hippocampal NPCs to favor neuron production. The excitation is sensed via Ca(v)1.2/1.3 (L-type) Ca(2+) channels and NMDA receptors on the proliferating precursors. Excitation through this pathway acts to inhibit expression of the glial fate genes Hes1 and Id2 and increase expression of NeuroD, a positive regulator of neuronal differentiation. These activity-sensing properties of the adult NPCs, when applied as an "excitation-neurogenesis coupling rule" within a Hebbian neural network, predict significant advantages for both the temporary storage and the clearance of memories.

Stem cell motility enables a density-dependent rate of fate commitment during scaled resizing of adult organs

NASA Astrophysics Data System (ADS)

Du, Xinxin; O'Brien, Lucy; Riedel-Kruse, Ingmar

Many adult organs grow or shrink to accommodate fluctuating levels of physiological demand. Specifically, the intestine of the fruit fly (the midgut) expands four-fold in the number of mature cells and, proportionally, the number of stem cells when the fly eats. However, the cellular behaviors that give rise to this stem scaling are not well-understood. Here we present a biophysical model of the adult fly midgut. A set of differential equations can recapitulate the physiological kinetics of cells during midgut growth and shrinkage as long as the rate of stem cell fate commitment depends on the stem cell number density in the tissue. To elucidate the source of this dependence, we model the tissue in a 2D simulation with soft spheres, where stem cells choose fate commitment through Delta-Notch pathway interactions with other stem cells, a known process in fly midguts. We find that as long as stem cells exhibit a large enough amplitude of random motion through the tissue (`stem cell motility'), and explore a large enough `territory' in their lifetime, stem cell scaling can occur. These model observations are confirmed through in vivo live-imaging, where we indeed see that stem cells are motile in the fly midgut.

PW1 gene/paternally expressed gene 3 (PW1/Peg3) identifies multiple adult stem and progenitor cell populations

PubMed Central

Besson, Vanessa; Smeriglio, Piera; Wegener, Amélie; Relaix, Frédéric; Nait Oumesmar, Brahim; Sassoon, David A.; Marazzi, Giovanna

2011-01-01

A variety of markers are invaluable for identifying and purifying stem/progenitor cells. Here we report the generation of a murine reporter line driven by Pw1 that reveals cycling and quiescent progenitor/stem cells in all adult tissues thus far examined, including the intestine, blood, testis, central nervous system, bone, skeletal muscle, and skin. Neurospheres generated from the adult PW1-reporter mouse show near 100% reporter-gene expression following a single passage. Furthermore, epidermal stem cells can be purified solely on the basis of reporter-gene expression. These cells are clonogenic, repopulate the epidermal stem-cell niches, and give rise to new hair follicles. Finally, we demonstrate that only PW1 reporter-expressing epidermal cells give rise to follicles that are capable of self-renewal following injury. Our data demonstrate that PW1 serves as an invaluable marker for competent self-renewing stem cells in a wide array of adult tissues, and the PW1-reporter mouse serves as a tool for rapid stem cell isolation and characterization. PMID:21709251

NAD⁺ repletion improves mitochondrial and stem cell function and enhances life span in mice.

PubMed

Zhang, Hongbo; Ryu, Dongryeol; Wu, Yibo; Gariani, Karim; Wang, Xu; Luan, Peiling; D'Amico, Davide; Ropelle, Eduardo R; Lutolf, Matthias P; Aebersold, Ruedi; Schoonjans, Kristina; Menzies, Keir J; Auwerx, Johan

2016-06-17

Adult stem cells (SCs) are essential for tissue maintenance and regeneration yet are susceptible to senescence during aging. We demonstrate the importance of the amount of the oxidized form of cellular nicotinamide adenine dinucleotide (NAD(+)) and its effect on mitochondrial activity as a pivotal switch to modulate muscle SC (MuSC) senescence. Treatment with the NAD(+) precursor nicotinamide riboside (NR) induced the mitochondrial unfolded protein response and synthesis of prohibitin proteins, and this rejuvenated MuSCs in aged mice. NR also prevented MuSC senescence in the mdx (C57BL/10ScSn-Dmd(mdx)/J) mouse model of muscular dystrophy. We furthermore demonstrate that NR delays senescence of neural SCs and melanocyte SCs and increases mouse life span. Strategies that conserve cellular NAD(+) may reprogram dysfunctional SCs and improve life span in mammals. Copyright © 2016, American Association for the Advancement of Science.

Perivascular Mesenchymal Stem Cells From the Adult Human Brain Harbor No Instrinsic Neuroectodermal but High Mesodermal Differentiation Potential.

PubMed

Lojewski, Xenia; Srimasorn, Sumitra; Rauh, Juliane; Francke, Silvan; Wobus, Manja; Taylor, Verdon; Araúzo-Bravo, Marcos J; Hallmeyer-Elgner, Susanne; Kirsch, Matthias; Schwarz, Sigrid; Schwarz, Johannes; Storch, Alexander; Hermann, Andreas

2015-10-01

Brain perivascular cells have recently been identified as a novel mesodermal cell type in the human brain. These cells reside in the perivascular niche and were shown to have mesodermal and, to a lesser extent, tissue-specific differentiation potential. Mesenchymal stem cells (MSCs) are widely proposed for use in cell therapy in many neurological disorders; therefore, it is of importance to better understand the "intrinsic" MSC population of the human brain. We systematically characterized adult human brain-derived pericytes during in vitro expansion and differentiation and compared these cells with fetal and adult human brain-derived neural stem cells (NSCs) and adult human bone marrow-derived MSCs. We found that adult human brain pericytes, which can be isolated from the hippocampus and from subcortical white matter, are-in contrast to adult human NSCs-easily expandable in monolayer cultures and show many similarities to human bone marrow-derived MSCs both regarding both surface marker expression and after whole transcriptome profile. Human brain pericytes showed a negligible propensity for neuroectodermal differentiation under various differentiation conditions but efficiently generated mesodermal progeny. Consequently, human brain pericytes resemble bone marrow-derived MSCs and might be very interesting for possible autologous and endogenous stem cell-based treatment strategies and cell therapeutic approaches for treating neurological diseases. Perivascular mesenchymal stem cells (MSCs) recently gained significant interest because of their appearance in many tissues including the human brain. MSCs were often reported as being beneficial after transplantation in the central nervous system in different neurological diseases; therefore, adult brain perivascular cells derived from human neural tissue were systematically characterized concerning neural stem cell and MSC marker expression, transcriptomics, and mesodermal and inherent neuroectodermal differentiation

Analysis of major elements in pigmented melanocytic chicken skin using laser-induced breakdown spectroscopy.

PubMed

Lee, Jong Jin; Moon, Youngmin; Han, Jung Hyun; Jeong, Sungho

2017-04-01

The concentration difference of major elements in melanocytic skin with respect to pigmentation level is analysed by laser-induced breakdown spectroscopy (LIBS) to investigate the applicability of LIBS as an in situ feedback tool for selective and complete laser removal of melanocytic skin tissue like nevus. The skin of black silkie chicken which had a characteristic darkly pigmented perifollicular skin surrounded by lightly pigmented extrafollicular skin was used as the sample. The results showed higher LIBS signal intensities of Ca 2+ and Mg 2+ but lower intensities of Na + , Cl - and K + in the perifollicular skin than in the extrafollicular skin, which demonstrated the feasibility to use LIBS as a reliable method to distinguish skin tissues with difference in pigmentation level. Plasma emission of biochemical elements generated with a laser irradiation on melanocytic skin lesion. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Melanin Transfer in Human 3D Skin Equivalents Generated Exclusively from Induced Pluripotent Stem Cells

PubMed Central

Gledhill, Karl; Guo, Zongyou; Umegaki-Arao, Noriko; Higgins, Claire A.; Itoh, Munenari; Christiano, Angela M.

2015-01-01

The current utility of 3D skin equivalents is limited by the fact that existing models fail to recapitulate the cellular complexity of human skin. They often contain few cell types and no appendages, in part because many cells found in the skin are difficult to isolate from intact tissue and cannot be expanded in culture. Induced pluripotent stem cells (iPSCs) present an avenue by which we can overcome this issue due to their ability to be differentiated into multiple cell types in the body and their unlimited growth potential. We previously reported generation of the first human 3D skin equivalents from iPSC-derived fibroblasts and iPSC-derived keratinocytes, demonstrating that iPSCs can provide a foundation for modeling a complex human organ such as skin. Here, we have increased the complexity of this model by including additional iPSC-derived melanocytes. Epidermal melanocytes, which are largely responsible for skin pigmentation, represent the second most numerous cell type found in normal human epidermis and as such represent a logical next addition. We report efficient melanin production from iPSC-derived melanocytes and transfer within an entirely iPSC-derived epidermal-melanin unit and generation of the first functional human 3D skin equivalents made from iPSC-derived fibroblasts, keratinocytes and melanocytes. PMID:26308443

Melanin Transfer in Human 3D Skin Equivalents Generated Exclusively from Induced Pluripotent Stem Cells.

PubMed

Gledhill, Karl; Guo, Zongyou; Umegaki-Arao, Noriko; Higgins, Claire A; Itoh, Munenari; Christiano, Angela M

2015-01-01

The current utility of 3D skin equivalents is limited by the fact that existing models fail to recapitulate the cellular complexity of human skin. They often contain few cell types and no appendages, in part because many cells found in the skin are difficult to isolate from intact tissue and cannot be expanded in culture. Induced pluripotent stem cells (iPSCs) present an avenue by which we can overcome this issue due to their ability to be differentiated into multiple cell types in the body and their unlimited growth potential. We previously reported generation of the first human 3D skin equivalents from iPSC-derived fibroblasts and iPSC-derived keratinocytes, demonstrating that iPSCs can provide a foundation for modeling a complex human organ such as skin. Here, we have increased the complexity of this model by including additional iPSC-derived melanocytes. Epidermal melanocytes, which are largely responsible for skin pigmentation, represent the second most numerous cell type found in normal human epidermis and as such represent a logical next addition. We report efficient melanin production from iPSC-derived melanocytes and transfer within an entirely iPSC-derived epidermal-melanin unit and generation of the first functional human 3D skin equivalents made from iPSC-derived fibroblasts, keratinocytes and melanocytes.

The AP-1 transcription factor FOSL1 causes melanocyte reprogramming and transformation.

PubMed

Maurus, K; Hufnagel, A; Geiger, F; Graf, S; Berking, C; Heinemann, A; Paschen, A; Kneitz, S; Stigloher, C; Geissinger, E; Otto, C; Bosserhoff, A; Schartl, M; Meierjohann, S

2017-09-07

The MAPK pathway is activated in the majority of melanomas and is the target of therapeutic approaches. Under normal conditions, it initiates the so-called immediate early response, which encompasses the transient transcription of several genes belonging to the AP-1 transcription factor family. Under pathological conditions, such as continuous MAPK pathway overactivation due to oncogenic alterations occurring in melanoma, these genes are constitutively expressed. The consequences of a permanent expression of these genes are largely unknown. Here, we show that FOSL1 is the main immediate early AP-1 member induced by melanoma oncogenes. We first examined its role in established melanoma cells. We found that FOSL1 is involved in melanoma cell migration as well as cell proliferation and anoikis-independent growth, which is mediated by the gene product of its target gene HMGA1, encoding a multipotent chromatin modifier. As FOSL1 expression is increased in patient melanoma samples compared to nevi, we investigated the effect of enhanced FOSL1 expression on melanocytes. Intriguingly, we found that FOSL1 acts oncogenic and transforms melanocytes, enabling subcutaneous tumor growth in vivo. During the process of transformation, FOSL1 reprogrammed the melanocytes and downregulated MITF in a HMGA1-dependent manner. At the same time, AXL was upregulated, leading to a shift in the MITF/AXL balance. Furthermore, FOSL1 re-enforced pro-tumorigenic transcription factors MYC, E2F3 and AP-1. Together, this led to the enhancement of several growth-promoting processes, such as ribosome biogenesis, cellular detachment and pyrimidine metabolism. Overall, we demonstrate that FOSL1 is a novel reprogramming factor for melanocytes with potent tumor transformation potential.

Genomic selection for quantitative adult plant stem rust resistance in wheat

USDA-ARS?s Scientific Manuscript database

Quantitative adult plant resistance (APR) to stem rust (Puccinia graminis f. sp. tritici) is an important breeding target in wheat (Triticum aestivum L.) and a potential target for genomic selection (GS). To evaluate the relative importance of known APR loci in applying genomic selection, we charact...

Activation of Sox3 Gene by Thyroid Hormone in the Developing Adult Intestinal Stem Cell During Xenopus Metamorphosis

PubMed Central

Sun, Guihong; Fu, Liezhen; Wen, Luan

2014-01-01

The maturation of the intestine into the adult form involves the formation of adult stem cells in a thyroid hormone (T3)-dependent process in vertebrates. In mammals, this takes place during postembryonic development, a period around birth when the T3 level peaks. Due to the difficulty of manipulating late-stage, uterus-enclosed embryos, very little is known about the development of the adult intestinal stem cells. Interestingly, the remodeling of the intestine during the T3-dependent amphibian metamorphosis mimics the maturation of mammalian intestine. Our earlier microarray studies in Xenopus laevis revealed that the transcription factor SRY (sex-determining region Y)-box 3 (Sox3), well known for its involvement in neural development, was upregulated in the intestinal epithelium during metamorphosis. Here, we show that Sox3 is highly and specifically expressed in the developing adult intestinal progenitor/stem cells. We further show that its induction by T3 is independent of new protein synthesis, suggesting that Sox3 is directly activated by liganded T3 receptor. Thus, T3 activates Sox3 as one of the earliest changes in the epithelium, and Sox3 in turn may facilitate the dedifferentiation of the larval epithelial cells into adult stem cells. PMID:25211587

Clonal population of adult stem cells: life span and differentiation potential.

PubMed

Seruya, Mitchel; Shah, Anup; Pedrotty, Dawn; du Laney, Tracey; Melgiri, Ryan; McKee, J Andrew; Young, Henry E; Niklason, Laura E

2004-01-01

Adult stem cells derived from bone marrow, connective tissue, and solid organs can exhibit a range of differentiation potentials. Some controversy exists regarding the classification of mesenchymal stem cells as bona fide stem cells, which is in part derived from the limited ability to propagate true clonal populations of precursor cells. We isolated putative mesenchymal stem cells from the connective tissue of an adult rat (rMSC), and generated clonal populations via three rounds of dilutional cloning. The replicative potential of the clonal rMSC line far exceeded Hayflick's limit of 50-70 population doublings. The high capacity for self-renewal in vitro correlated with telomerase activity, as demonstrated by telomerase repeat amplification protocol (TRAP) assay. Exposure to nonspecific differentiation culture medium revealed multilineage differentiation potential of rMSC clones. Immunostaining confirmed the appearance of mesodermal phenotypes, including adipocytes possessing lipid-rich vacuoles, chondrocytes depositing pericellular type II collagen, and skeletal myoblasts expressing MyoD1. Importantly, the spectrum of differentiation capability was sustained through repeated passaging. Furthermore, serum-free conditions that led to high-efficiency smooth muscle differentiation were identified. rMSCs plated on collagen IV-coated surfaces and exposed to transforming growth factor-beta1 (TGF-beta1) differentiated into a homogeneous population expressing alpha-actin and calponin. Hence, clonogenic analysis confirmed the presence of a putative MSC population derived from the connective tissue of rat skeletal muscle. The ability to differentiate into a smooth muscle cell (SMC) phenotype, combined with a high proliferative capacity, make such a connective tissue-derived MSC population ideal for applications in vascular tissue construction.

Effects of low-dose heavy ions on embryonic development in mice and on melanocyte differentiation in the epidermis and hair bulb.

PubMed

Hirobe, Tomohisa; Eguchi-Kasai, Kiyomi; Sugaya, Kimihiko; Murakami, Masahiro

2013-05-01

The effects of prenatal low-dose irradiation with heavy ions on embryonic development in mice and on melanocyte differentiation are not well understood. We performed whole-body irradiation of pregnant C57BL/10J mice at embryonic Day 9 (E9) with a single dose of γ-rays, silicon, argon or iron ions. The number of living embryos and embryonic body weight at E18 decreased after exposure to heavy ions at high doses. Malformations such as small eyes and limb anomalies were observed in heavy-ion-treated embryos, but not in γ-ray-treated embryos. The frequency of abnormally curved tails was increased by exposure to γ-rays and argon and iron ions even at a dose of 0.1 Gy (P < 0.05). In contrast, a dose-dependent decrease in the number of epidermal melanoblasts/melanocytes and hair bulb melanocytes was observed after 0.1 Gy irradiation with γ-rays or heavy ions (P < 0.01). The decrease in the number of dorsal hair bulb melanocytes, dorsal and ventral epidermal melanoblasts/melanocytes and ventral hair bulb melanocytes was not necessarily correlated with the linear energy transfer of the radiation tested. Moreover, the effects of heavy ions were larger on the ventral skin than on the dorsal skin, indicating that the sensitivity of melanocytes to heavy ions differs between the dorsal and ventral skin. Taken together, these results suggest that the effects of the low-dose heavy ions differ between cell types and tissues, and the effects on the prenatal development of mice and melanocyte development are not necessarily greater than those of γ-rays.

Effects of low-dose heavy ions on embryonic development in mice and on melanocyte differentiation in the epidermis and hair bulb

PubMed Central

Hirobe, Tomohisa; Eguchi-Kasai, Kiyomi; Sugaya, Kimihiko; Murakami, Masahiro

2013-01-01

The effects of prenatal low-dose irradiation with heavy ions on embryonic development in mice and on melanocyte differentiation are not well understood. We performed whole-body irradiation of pregnant C57BL/10J mice at embryonic Day 9 (E9) with a single dose of γ-rays, silicon, argon or iron ions. The number of living embryos and embryonic body weight at E18 decreased after exposure to heavy ions at high doses. Malformations such as small eyes and limb anomalies were observed in heavy-ion-treated embryos, but not in γ-ray-treated embryos. The frequency of abnormally curved tails was increased by exposure to γ-rays and argon and iron ions even at a dose of 0.1 Gy (P < 0.05). In contrast, a dose-dependent decrease in the number of epidermal melanoblasts/melanocytes and hair bulb melanocytes was observed after 0.1 Gy irradiation with γ-rays or heavy ions (P < 0.01). The decrease in the number of dorsal hair bulb melanocytes, dorsal and ventral epidermal melanoblasts/melanocytes and ventral hair bulb melanocytes was not necessarily correlated with the linear energy transfer of the radiation tested. Moreover, the effects of heavy ions were larger on the ventral skin than on the dorsal skin, indicating that the sensitivity of melanocytes to heavy ions differs between the dorsal and ventral skin. Taken together, these results suggest that the effects of the low-dose heavy ions differ between cell types and tissues, and the effects on the prenatal development of mice and melanocyte development are not necessarily greater than those of γ-rays. PMID:23230241

Stem Cells

MedlinePlus

Stem cells are cells with the potential to develop into many different types of cells in the body. They serve as a repair ... body. There are two main types of stem cells: embryonic stem cells and adult stem cells. Stem ...

Diagnosis and staging of female genital tract melanocytic lesions using pump-probe microscopy (Conference Presentation)

NASA Astrophysics Data System (ADS)

Robles, Francisco E.; Selim, Maria A.; Warren, Warren S.

2016-02-01

Melanoma of the vulva is the second most common type of malignancy afflicting that organ. This disease caries poor prognosis, and shows tendencies to recur locally and develop distant metastases through hematogenous dissemination. Further, there exists significant clinical overlap between early-stage melanomas and melanotic macules, benign lesions that are believed to develop in about 10% of the general female population. In this work we apply a novel nonlinear optical method, pump-probe microscopy, to quantitatively analyze female genitalia tract melanocytic lesions. Pump-probe microscopy provides chemical information of endogenous pigments by probing their electronic excited state dynamics, with subcellular resolution. Using unstained biopsy sections from 31 patients, we find significant differences between melanin type and structure in tissue regions with invasive melanoma, melanoma in-situ and non-malignant melanocytic proliferations (e.g., nevi, melanocytic macules). The molecular images of non-malignant lesion have a well-organized structure, with relatively homogenous pigment chemistry, most often consistent with that of eumelanin with large aggregate size or void of metals, such as iron. On the other hand, pigment type and structure observed in melanomas in-situ and invasive melanomas is typically much more heterogeneous, with larger contributions from pheomelanin, melanins with larger metal content, and/or melanins with smaller aggregate size. Of most significance, clear differences can be observed between melanocytic macules and vulvar melanoma in-situ, which, as discussed above, can be difficult to clinically distinguish. This initial study demonstrates pump-probe microscopy's potential as an adjuvant diagnostic tool by revealing systematic chemical and morphological differences in melanin pigmentation among invasive melanoma, melanoma in-situ and non-malignant melanocytic lesions.

Impact of electromagnetic fields on stem cells: common mechanisms at the crossroad between adult neurogenesis and osteogenesis

PubMed Central

Leone, Lucia; Podda, Maria Vittoria; Grassi, Claudio

2015-01-01

In the recent years adult neural and mesenchymal stem cells have been intensively investigated as effective resources for repair therapies. In vivo and in vitro studies have provided insights on the molecular mechanisms underlying the neurogenic and osteogenic processes in adulthood. This knowledge appears fundamental for the development of targeted strategies to manipulate stem cells. Here we review recent literature dealing with the effects of electromagnetic fields on stem cell biology that lends support to their use as a promising tool to positively influence the different steps of neurogenic and osteogenic processes. We will focus on recent studies revealing that extremely-low frequency electromagnetic fields enhance adult hippocampal neurogenesis by inducing epigenetic modifications on the regulatory sequences of genes responsible for neural stem cell proliferation and neuronal differentiation. In light of the emerging critical role played by chromatin modifications in maintaining the stemness as well as in regulating stem cell differentiation, we will also attempt to exploit epigenetic changes that can represent common targets for electromagnetic field effects on neurogenic and osteogenic processes. PMID:26124705

Is There Any Reason to Prefer Cord Blood Instead of Adult Donors for Hematopoietic Stem Cell Transplants?

PubMed

Beksac, Meral

2015-01-01

As cord blood (CB) enables rapid access and tolerance to HLA mismatches, a number of unrelated CB transplants have reached 30,000. Such transplant activity has been the result of international accreditation programs maintaining highly qualified cord blood units (CBUs) reaching more than 600,000 CBUs stored worldwide. Efforts to increase stem cell content or engraftment rate of the graft by ex vivo expansion, modulation by molecules such as fucose, prostaglandin E2 derivative, complement CD26 inhibitors, or CXCR4/CXCL12 axis have been able to accelerate engraftment speed and rate. Furthermore, introduction of reduced intensity conditioning protocols, better HLA matching, and recognition of the importance of HLA-C have improved CB transplants success by decreasing transplant-related mortality. CB progenitor/stem cell content has been compared with adult stem cells revealing higher long-term repopulating capacity compared to bone marrow-mesenchymal stromal cells and lesser oncogenic potential than progenitor-induced stem cells. This chapter summarizes the advantages and disadvantages of CB compared to adult stem cells within the context of stem cell biology and transplantation.

Monoclonal antibody (AFH1) immunoreactive on morphologically abnormal basal melanocytes within dysplastic nevi, nevocellular nevus nests, and melanoma.

PubMed

Aronson, P J; Ito, K; Fukaya, T; Hashimoto, K; Mehregan, A H

1988-04-01

The mouse monoclonal antibody AFH1 was produced using formalin-fixed, sham paraffin-embedded human melanoma cell culture line A375 as immunogen. Reactivity of this antibody was assessed by immunohistochemical techniques against formalin- or acid alcohol-fixed paraffin-embedded tissue as well as formalin- or acid alcohol-fixed unembedded lesions. Ninety-seven nevomelanocytic lesions, neurofibromas, epithelial lesions, and a plasmacellular infiltrate were evaluated. AFH1 was immunoreactive on 54 of 55 nevocytic lesions (98.2%), 15 of 16 primary melanomas (93.7%), a lentigo maligna, and nests in 21 of 21 dysplastic nevi (100%). Of 100 consecutive basal melanocytes of intraepidermal melanoma cells counted in each lesion, mean AFH1 immunoreactivity for nonnested basal melanocytes in nevocellular nevi was 3.8%; for dysplastic nevi, 13.8%; and for intraepidermal melanoma cells, 78.0%. When nonnested basal melanocytes were subdivided into cytologically normal and abnormal cell groups, AFH1 immunoreactivity was 9.4% and 72.6%, respectively. AFH1 recognition of the lentiginous portion of dysplastic nevi corresponds statistically to the appearance of abnormal melanocyte cytology, nest formation, or both. Using 50% immunoreactive nonnested melanocytes as the criterion, AFH1 seems to distinguish primary melanoma from dysplastic nevi with a sensitivity of 93.8% and a specificity of 95.8%.

Coexistence of congenital giant melanocytic nevus of the scalp with cranial defect, poliosis, and hair loss.

PubMed

Lee, Woo J; Lee, Sang M; Won, Chong H; Chang, Sung E; Lee, Mi W; Choi, Jee H; Moon, Kee C

2013-01-01

Congenital melanocytic nevi (CMN) are pigmented lesions presenting on the skin in approximately 1% of all newborns at or shortly after birth. CMN have been described as being associated with several anomalies, including cranial bone hypertrophy, scoliosis, and spina bifida. This is the first report to describe a giant congenital melanocytic nevus on the scalp associated with cranial involvement, poliosis, and alopecia. © 2013 Wiley Periodicals, Inc.

Evolutionary dynamics of adult stem cells: comparison of random and immortal-strand segregation mechanisms.

PubMed

Tannenbaum, Emmanuel; Sherley, James L; Shakhnovich, Eugene I

2005-04-01

This paper develops a point-mutation model describing the evolutionary dynamics of a population of adult stem cells. Such a model may prove useful for quantitative studies of tissue aging and the emergence of cancer. We consider two modes of chromosome segregation: (1) random segregation, where the daughter chromosomes of a given parent chromosome segregate randomly into the stem cell and its differentiating sister cell and (2) "immortal DNA strand" co-segregation, for which the stem cell retains the daughter chromosomes with the oldest parent strands. Immortal strand co-segregation is a mechanism, originally proposed by [Cairns Nature (London) 255, 197 (1975)], by which stem cells preserve the integrity of their genomes. For random segregation, we develop an ordered strand pair formulation of the dynamics, analogous to the ordered strand pair formalism developed for quasispecies dynamics involving semiconservative replication with imperfect lesion repair (in this context, lesion repair is taken to mean repair of postreplication base-pair mismatches). Interestingly, a similar formulation is possible with immortal strand co-segregation, despite the fact that this segregation mechanism is age dependent. From our model we are able to mathematically show that, when lesion repair is imperfect, then immortal strand co-segregation leads to better preservation of the stem cell lineage than random chromosome segregation. Furthermore, our model allows us to estimate the optimal lesion repair efficiency for preserving an adult stem cell population for a given period of time. For human stem cells, we obtain that mispaired bases still present after replication and cell division should be left untouched, to avoid potentially fixing a mutation in both DNA strands.

Evolutionary dynamics of adult stem cells: Comparison of random and immortal-strand segregation mechanisms

NASA Astrophysics Data System (ADS)

Tannenbaum, Emmanuel; Sherley, James L.; Shakhnovich, Eugene I.

2005-04-01

This paper develops a point-mutation model describing the evolutionary dynamics of a population of adult stem cells. Such a model may prove useful for quantitative studies of tissue aging and the emergence of cancer. We consider two modes of chromosome segregation: (1) random segregation, where the daughter chromosomes of a given parent chromosome segregate randomly into the stem cell and its differentiating sister cell and (2) “immortal DNA strand” co-segregation, for which the stem cell retains the daughter chromosomes with the oldest parent strands. Immortal strand co-segregation is a mechanism, originally proposed by [Cairns Nature (London) 255, 197 (1975)], by which stem cells preserve the integrity of their genomes. For random segregation, we develop an ordered strand pair formulation of the dynamics, analogous to the ordered strand pair formalism developed for quasispecies dynamics involving semiconservative replication with imperfect lesion repair (in this context, lesion repair is taken to mean repair of postreplication base-pair mismatches). Interestingly, a similar formulation is possible with immortal strand co-segregation, despite the fact that this segregation mechanism is age dependent. From our model we are able to mathematically show that, when lesion repair is imperfect, then immortal strand co-segregation leads to better preservation of the stem cell lineage than random chromosome segregation. Furthermore, our model allows us to estimate the optimal lesion repair efficiency for preserving an adult stem cell population for a given period of time. For human stem cells, we obtain that mispaired bases still present after replication and cell division should be left untouched, to avoid potentially fixing a mutation in both DNA strands.

Asymmetry and irregularity border as discrimination factor between melanocytic lesions

NASA Astrophysics Data System (ADS)

Sbrissa, David; Pratavieira, Sebastião.; Salvio, Ana Gabriela; Kurachi, Cristina; Bagnato, Vanderlei Salvadori; Costa, Luciano Da Fontoura; Travieso, Gonzalo

2015-06-01

Image processing tools have been widely used in systems supporting medical diagnosis. The use of mobile devices for the diagnosis of melanoma can assist doctors and improve their diagnosis of a melanocytic lesion. This study proposes a method of image analysis for melanoma discrimination from other types of melanocytic lesions, such as regular and atypical nevi. The process is based on extracting features related with asymmetry and border irregularity. It were collected 104 images, from medical database of two years. The images were obtained with standard digital cameras without lighting and scale control. Metrics relating to the characteristics of shape, asymmetry and curvature of the contour were extracted from segmented images. Linear Discriminant Analysis was performed for dimensionality reduction and data visualization. Segmentation results showed good efficiency in the process, with approximately 88:5% accuracy. Validation results presents sensibility and specificity 85% and 70% for melanoma detection, respectively.

Exposure of human melanocytes to UVB twice and subsequent incubation leads to cellular senescence and senescence-associated pigmentation through the prolonged p53 expression.

PubMed

Choi, Suh-Yeon; Bin, Bum-Ho; Kim, Wanil; Lee, Eunkyung; Lee, Tae Ryong; Cho, Eun-Gyung

2018-06-01

Ultraviolet radiation (UVR) is a well-known factor in skin aging and pigmentation, and daily exposure to subcytotoxic doses of UVR might accelerate senescence and senescence-associated phenomena in human melanocytes. To establish an in vitro melanocyte model to mimic the conditions of repeated exposure to subcytotoxic doses of UVB irradiation and to investigate key factor(s) for melanocyte senescence and senescence-associated phenomena. Human epidermal melanocytes were exposed twice with 20 mJ/cm 2 UVB over a 24-h interval and subsequently cultivated for 2 weeks. Senescent phenotypes were addressed morphologically, and by measuring the senescence-associated β-galactosidase (SA-β-Gal) activity, cell proliferation capacity with cell cycle analysis, and melanin content. The established protocol successfully induced melanocyte senescence, and senescent melanocytes accompanied hyperpigmentation. Prolonged expression of p53 was responsible for melanocyte senescence and hyperpigmentation, and treatment with the p53-inhibitor pifithrin-α at 2-weeks post-UVB irradiation, but not at 48 h, significantly reduced melanin content along with decreases in tyrosinase levels. Melanocyte senescence model will be useful for studying the long-term effects of UVB irradiation and pigmentation relevant to physiological photoaging, and screening compounds effective for senescence-associated p53-mediated pigmentation. Copyright © 2018 Japanese Society for Investigative Dermatology. Published by Elsevier B.V. All rights reserved.

Integrated genomic classification of melanocytic tumors of the central nervous system using mutation analysis, copy number alterations and DNA methylation profiling.

PubMed

Griewank, Klaus; Koelsche, Christian; van de Nes, Johannes A P; Schrimpf, Daniel; Gessi, Marco; Möller, Inga; Sucker, Antje; Scolyer, Richard A; Buckland, Michael E; Murali, Rajmohan; Pietsch, Torsten; von Deimling, Andreas; Schadendorf, Dirk

2018-06-11

In the central nervous system, distinguishing primary leptomeningeal melanocytic tumors from melanoma metastases and predicting their biological behavior solely using histopathologic criteria can be challenging. We aimed to assess the diagnostic and prognostic value of integrated molecular analysis. Targeted next-generation-sequencing, array-based genome-wide methylation analysis and BAP1 immunohistochemistry was performed on the largest cohort of central nervous system melanocytic tumors analyzed to date, incl. 47 primary tumors of the central nervous system, 16 uveal melanomas. 13 cutaneous melanoma metastasis and 2 blue nevus-like melanomas. Gene mutation, DNA-methylation and copy-number profiles were correlated with clinicopathological features. Combining mutation, copy-number and DNA-methylation profiles clearly distinguished cutaneous melanoma metastases from other melanocytic tumors. Primary leptomeningeal melanocytic tumors, uveal melanomas and blue nevus-like melanoma showed common DNA-methylation, copy-number alteration and gene mutation signatures. Notably, tumors demonstrating chromosome 3 monosomy and BAP1 alterations formed a homogeneous subset within this group. Integrated molecular profiling aids in distinguishing primary from metastatic melanocytic tumors of the central nervous system. Primary leptomeningeal melanocytic tumors, uveal melanoma and blue nevus-like melanoma share molecular similarity with chromosome 3 and BAP1 alterations markers of poor prognosis. Copyright ©2018, American Association for Cancer Research.

Olfactory epithelium: Cells, clinical disorders, and insights from an adult stem cell niche

PubMed Central

Choi, Rhea

2018-01-01

Disorders causing a loss of the sense of smell remain a therapeutic challenge. Basic research has, however, greatly expanded our knowledge of the organization and function of the olfactory system. This review describes advances in our understanding of the cellular components of the peripheral olfactory system, specifically the olfactory epithelium in the nose. The article discusses recent findings regarding the mechanisms involved in regeneration and cellular renewal from basal stem cells in the adult olfactory epithelium, considering the strategies involved in embryonic olfactory development and insights from research on other stem cell niches. In the context of clinical conditions causing anosmia, the current view of adult olfactory neurogenesis, tissue homeostasis, and failures in these processes is considered, along with current and future treatment strategies. Level of Evidence NA PMID:29492466

The helix-loop-helix protein id1 controls stem cell proliferation during regenerative neurogenesis in the adult zebrafish telencephalon.

PubMed

Rodriguez Viales, Rebecca; Diotel, Nicolas; Ferg, Marco; Armant, Olivier; Eich, Julia; Alunni, Alessandro; März, Martin; Bally-Cuif, Laure; Rastegar, Sepand; Strähle, Uwe

2015-03-01

The teleost brain has the remarkable ability to generate new neurons and to repair injuries during adult life stages. Maintaining life-long neurogenesis requires careful management of neural stem cell pools. In a genome-wide expression screen for transcription regulators, the id1 gene, encoding a negative regulator of E-proteins, was found to be upregulated in response to injury. id1 expression was mapped to quiescent type I neural stem cells in the adult telencephalic stem cell niche. Gain and loss of id1 function in vivo demonstrated that Id1 promotes stem cell quiescence. The increased id1 expression observed in neural stem cells in response to injury appeared independent of inflammatory signals, suggesting multiple antagonistic pathways in the regulation of reactive neurogenesis. Together, we propose that Id1 acts to maintain the neural stem cell pool by counteracting neurogenesis-promoting signals. © 2014 AlphaMed Press.

Role of microRNA508-3p in melanogenesis by targeting microphthalmia transcription factor in melanocytes of alpaca.

PubMed

Zhang, J; Liu, Y; Zhu, Z; Yang, S; Ji, K; Hu, S; Liu, X; Yao, J; Fan, R; Dong, C

2017-02-01

It has been demonstrated that microRNAs (miRNAs) play important roles in the control of melanogenesis and hair color in mammals. By comparing miRNA expression profiles between brown and white alpaca skin, we previously identified miR508-3p as a differentially expressed miRNA suggesting its potential role in melanogenesis and hair color formation. The present study was conducted to determine the role of miR508-3p in melanogenesis in alpaca melanocytes. In situ hybridization showed that miR508-3p is abundantly present in the cytoplasma of alpaca melanocytes. miR508-3p was predicted to target the gene encoding microphthalmia transcription factor (MITF) and a luciferase reporter assay indicated that miR508-3p regulates MITF expression by directly targeting its 3'UTR. Overexpression of miR508-3p in alpaca melanocytes down-regulated MITF expression both at the messenger RNA and protein level and resulted in decreased expression of key melanogenic genes including tyrosinase and tyrosinase-related protein 2. Overexpression of miR508-3p in melanocytes also resulted in decreased melanin production including total alkali-soluble melanogenesis, eumelanogenesis and pheomelanogenesis. Results support a functional role of miR508-3p in regulating melanogenesis in alpaca melanocytes by directly targeting MITF.

Activity-dependent signaling mechanisms regulating adult hippocampal neural stem cells and their progeny.

PubMed

Crowther, Andrew J; Song, Juan

2014-08-01

Adult neural stem cells (NSCs) reside in a restricted microenvironment, where their development is controlled by subtle and presently underexplored cues. This raises a significant question: what instructions must be provided by this supporting niche to regulate NSC development and functions? Signaling from the niche is proposed to control many aspects of NSC behavior, including balancing the quiescence and proliferation of NSCs, determining the cell division mode (symmetric versus asymmetric), and preventing premature depletion of stem cells to maintain neurogenesis throughout life. Interactions between neurogenic niches and NSCs also govern the homeostatic regulation of adult neurogenesis under diverse physiological, environmental, and pathological conditions. An important implication from revisiting many previously-identifi ed regulatory factors is that most of them (e.g., the antidepressant fluoxetine and exercise) affect gross neurogenesis by acting downstream of NSCs at the level of intermediate progenitors and neuroblasts, while leaving the NSC pool unaffected. Therefore, it is critically important to address how various niche components, signaling pathways, and environmental stimuli differentially regulate distinct stages of adult neurogenesis.

Vitiligo-inducing phenols activate the unfolded protein response in melanocytes resulting in upregulation of IL6 and IL8.

PubMed

Toosi, Siavash; Orlow, Seth J; Manga, Prashiela

2012-11-01

Vitiligo is characterized by depigmented skin patches caused by loss of epidermal melanocytes. Oxidative stress may have a role in vitiligo onset, while autoimmunity contributes to disease progression. In this study, we sought to identify mechanisms that link disease triggers and spreading of lesions. A hallmark of melanocytes at the periphery of vitiligo lesions is dilation of the endoplasmic reticulum (ER). We hypothesized that oxidative stress results in redox disruptions that extend to the ER, causing accumulation of misfolded peptides, which activates the unfolded protein response (UPR). We used 4-tertiary butyl phenol and monobenzyl ether of hydroquinone, known triggers of vitiligo. We show that expression of key UPR components, including the transcription factor X-box-binding protein 1 (XBP1), is increased following exposure of melanocytes to phenols. XBP1 activation increases production of immune mediators IL6 and IL8. Co-treatment with XBP1 inhibitors reduced IL6 and IL8 production induced by phenols, while overexpression of XBP1 alone increased their expression. Thus, melanocytes themselves produce cytokines associated with activation of an immune response following exposure to chemical triggers of vitiligo. These results expand our understanding of the mechanisms underlying melanocyte loss in vitiligo and pathways linking environmental stressors and autoimmunity.

Vitiligo inducing phenols activate the unfolded protein response in melanocytes resulting in upregulation of IL6 and IL8

PubMed Central

Toosi, Siavash; Orlow, Seth J.; Manga, Prashiela

2012-01-01

Vitiligo is characterized by depigmented skin patches due to loss of epidermal melanocytes. Oxidative stress may play a role in vitiligo onset, while autoimmunity contributes to disease progression. In this study we sought to identify mechanisms that link disease triggers and spreading of lesions. A hallmark of melanocytes at the periphery of vitiligo lesions is dilation of the endoplasmic reticulum (ER). We hypothesized that oxidative stress results in redox disruptions that extend to the ER, causing accumulation of misfolded peptides, which activates the unfolded protein response (UPR). We used 4-tertiary butyl phenol (4-TBP) and monobenzyl ether of hydroquinone (MBEH), known triggers of vitiligo. We show that expression of key UPR components, including the transcription factor X-box binding protein 1 (XBP1), are increased following exposure of melanocytes to phenols. XBP1 activation increases production of immune mediators interleukin-6 (IL6) and IL8. Co-treatment with XBP1 inhibitors reduced IL6 and IL8 production induced by phenols, while over-expression of XBP1 alone increased their expression. Thus, melanocytes themselves produce cytokines associated with activation of an immune response following exposure to chemical triggers of vitiligo. These results expand our understanding of the mechanisms underlying melanocyte loss in vitiligo and pathways linking environmental stressors and autoimmunity. PMID:22696056

How electromagnetic fields can influence adult stem cells: positive and negative impacts.

PubMed

Maziarz, Aleksandra; Kocan, Beata; Bester, Mariusz; Budzik, Sylwia; Cholewa, Marian; Ochiya, Takahiro; Banas, Agnieszka

2016-04-18

The electromagnetic field (EMF) has a great impact on our body. It has been successfully used in physiotherapy for the treatment of bone disorders and osteoarthritis, as well as for cartilage regeneration or pain reduction. Recently, EMFs have also been applied in in vitro experiments on cell/stem cell cultures. Stem cells reside in almost all tissues within the human body, where they exhibit various potential. These cells are of great importance because they control homeostasis, regeneration, and healing. Nevertheless, stem cells when become cancer stem cells, may influence the pathological condition. In this article we review the current knowledge on the effects of EMFs on human adult stem cell biology, such as proliferation, the cell cycle, or differentiation. We present the characteristics of the EMFs used in miscellaneous assays. Most research has so far been performed during osteogenic and chondrogenic differentiation of mesenchymal stem cells. It has been demonstrated that the effects of EMF stimulation depend on the intensity and frequency of the EMF and the time of exposure to it. However, other factors may affect these processes, such as growth factors, reactive oxygen species, and so forth. Exploration of this research area may enhance the development of EMF-based technologies used in medical applications and thereby improve stem cell-based therapy and tissue engineering.

Hierarchical maintenance of MLL myeloid leukemia stem cells employs a transcriptional program shared with embryonic rather than adult stem cells

PubMed Central

Somervaille, Tim C. P.; Matheny, Christina J.; Spencer, Gary J.; Iwasaki, Masayuki; Rinn, John L.; Witten, Daniela M.; Chang, Howard Y.; Shurtleff, Sheila A.; Downing, James R.; Cleary, Michael L.

2009-01-01

Summary The genetic programs that promote retention of self-renewing leukemia stem cells (LSCs) at the apex of cellular hierarchies in acute myeloid leukemia (AML) are not known. In a mouse model of human AML, LSCs exhibit variable frequencies that correlate with the initiating MLL oncogene and are maintained in a self-renewing state by a transcriptional sub-program more akin to that of embryonic stem cells (ESCs) than adult stem cells. The transcription/chromatin regulatory factors Myb, Hmgb3 and Cbx5 are critical components of the program and suffice for Hoxa/Meis-independent immortalization of myeloid progenitors when co-expressed, establishing the cooperative and essential role of an ESC-like LSC maintenance program ancillary to the leukemia initiating MLL/Hox/Meis program. Enriched expression of LSC maintenance and ESC-like program genes in normal myeloid progenitors and poor prognosis human malignancies links the frequency of aberrantly self-renewing progenitor-like cancer stem cells to prognosis in human cancer. PMID:19200802

Primary Cilia Negatively Regulate Melanogenesis in Melanocytes and Pigmentation in a Human Skin Model.

PubMed

Choi, Hyunjung; Shin, Ji Hyun; Kim, Eun Sung; Park, So Jung; Bae, Il-Hong; Jo, Yoon Kyung; Jeong, In Young; Kim, Hyoung-June; Lee, Youngjin; Park, Hea Chul; Jeon, Hong Bae; Kim, Ki Woo; Lee, Tae Ryong; Cho, Dong-Hyung

2016-01-01

The primary cilium is an organelle protruding from the cell body that senses external stimuli including chemical, mechanical, light, osmotic, fluid flow, and gravitational signals. Skin is always exposed to the external environment and responds to external stimuli. Therefore, it is possible that primary cilia have an important role in skin. Ciliogenesis was reported to be involved in developmental processes in skin, such as keratinocyte differentiation and hair formation. However, the relation between skin pigmentation and primary cilia is largely unknown. Here, we observed that increased melanogenesis in melanocytes treated with a melanogenic inducer was inhibited by a ciliogenesis inducer, cytochalasin D, and serum-free culture. However, these inhibitory effects disappeared in GLI2 knockdown cells. In addition, activation of sonic hedgehog (SHH)-smoothened (Smo) signaling pathway by a Smo agonist, SAG inhibited melanin synthesis in melanocytes and pigmentation in a human skin model. On the contrary, an inhibitor of primary cilium formation, ciliobrevin A1, activated melanogenesis in melanocytes. These results suggest that skin pigmentation may be regulated partly by the induction of ciliogenesis through Smo-GLI2 signaling.

A novel stilbene-like compound that inhibits melanoma growth by regulating melanocyte differentiation and proliferation.

PubMed

Stueven, Noah A; Schlaeger, Nicholas M; Monte, Aaron P; Hwang, Sheng-Ping L; Huang, Cheng-Chen

2017-12-15

Melanoma is the most aggressive form of skin cancer. Current challenges to melanoma therapy include the adverse effects from immunobiologics, resistance to drugs targeting the MAPK pathway, intricate interaction of many signal pathways, and cancer heterogeneity. Thus combinational therapy with drugs targeting multiple signaling pathways becomes a new promising therapy. Here, we report a family of stilbene-like compounds called A11 that can inhibit melanoma growth in both melanoma-forming zebrafish embryos and mouse melanoma cells. The growth inhibition by A11 is a result of mitosis reduction but not apoptosis enhancement. Meanwhile, A11 activates both MAPK and Akt signaling pathways. Many A11-treated mouse melanoma cells exhibit morphological changes and resemble normal melanocytes. Furthermore, we found that A11 causes down-regulation of melanocyte differentiation genes, including Pax3 and MITF. Together, our results suggest that A11 could be a new melanoma therapeutic agent by inhibiting melanocyte differentiation and proliferation. Copyright © 2017 Elsevier Inc. All rights reserved.

Adult neural stem cell cycling in vivo requires thyroid hormone and its alpha receptor.

PubMed

Lemkine, G F; Raj, A; Alfama, G; Turque, N; Hassani, Z; Alegria-Prévot, O; Samarut, J; Levi, G; Demeneix, B A

2005-05-01

Thyroid hormones (TH) are essential for brain development. However, information on if and how this key endocrine factor affects adult neurogenesis is fragmentary. We thus investigated the effects of TH on proliferation and apoptosis of stem cells in the subventricular zone (SVZ), as well as on migration of transgene-tagged neuroblasts out of the stem cell niche. Hypothyroidism significantly reduced all three of these processes, inhibiting generation of new cells. To determine the mechanisms relaying TH action in the SVZ, we analyzed which receptor was implicated and whether the effects were played out directly at the level of the stem cell population. The alpha TH receptor (TRalpha), but not TRbeta, was found to be expressed in nestin positive progenitor cells of the SVZ. Further, use of TRalpha mutant mice showed TRalpha to be required to maintain full proliferative activity. Finally, a direct TH transcriptional effect, not mediated through other cell populations, was revealed by targeted gene transfer to stem cells in vivo. Indeed, TH directly modulated transcription from the c-myc promoter reporter construct containing a functional TH response element containing TRE but not from a mutated TRE sequence. We conclude that liganded-TRalpha is critical for neurogenesis in the adult mammalian brain.

Spontaneous transformation of adult mesenchymal stem cells from cynomolgus macaques in vitro

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ren, Zhenhua; Key Laboratory of Neurodegeneration, Ministry of Education, Beijing; Department of Anatomy, Anhui Medical University, Hefei, 230032

2011-12-10

Mesenchymal stem cells (MSCs) have shown potential clinical utility in cell therapy and tissue engineering, due to their ability to proliferate as well as to differentiate into multiple lineages, including osteogenic, adipogenic, and chondrogenic specifications. Therefore, it is crucial to assess the safety of MSCs while extensive expansion ex vivo is a prerequisite to obtain the cell numbers for cell transplantation. Here we show that MSCs derived from adult cynomolgus monkey can undergo spontaneous transformation following in vitro culture. In comparison with MSCs, the spontaneously transformed mesenchymal cells (TMCs) display significantly different growth pattern and morphology, reminiscent of the characteristicsmore » of tumor cells. Importantly, TMCs are highly tumorigenic, causing subcutaneous tumors when injected into NOD/SCID mice. Moreover, no multiple differentiation potential of TMCs is observed in vitro or in vivo, suggesting that spontaneously transformed adult stem cells may not necessarily turn into cancer stem cells. These data indicate a direct transformation of cynomolgus monkey MSCs into tumor cells following long-term expansion in vitro. The spontaneous transformation of the cultured cynomolgus monkey MSCs may have important implications for ongoing clinical trials and for models of oncogenesis, thus warranting a more strict assessment of MSCs prior to cell therapy. -- Highlights: Black-Right-Pointing-Pointer Spontaneous transformation of cynomolgus monkey MSCs in vitro. Black-Right-Pointing-Pointer Transformed mesenchymal cells lack multipotency. Black-Right-Pointing-Pointer Transformed mesenchymal cells are highly tumorigenic. Black-Right-Pointing-Pointer Transformed mesenchymal cells do not have the characteristics of cancer stem cells.« less

Embryonic origin of adult stem cells required for tissue homeostasis and regeneration

PubMed Central

Davies, Erin L; Lei, Kai; Seidel, Christopher W; Kroesen, Amanda E; McKinney, Sean A; Guo, Longhua; Robb, Sofia MC; Ross, Eric J; Gotting, Kirsten; Alvarado, Alejandro Sánchez

2017-01-01

Planarian neoblasts are pluripotent, adult somatic stem cells and lineage-primed progenitors that are required for the production and maintenance of all differentiated cell types, including the germline. Neoblasts, originally defined as undifferentiated cells residing in the adult parenchyma, are frequently compared to embryonic stem cells yet their developmental origin remains obscure. We investigated the provenance of neoblasts during Schmidtea mediterranea embryogenesis, and report that neoblasts arise from an anarchic, cycling piwi-1+ population wholly responsible for production of all temporary and definitive organs during embryogenesis. Early embryonic piwi-1+ cells are molecularly and functionally distinct from neoblasts: they express unique cohorts of early embryo enriched transcripts and behave differently than neoblasts in cell transplantation assays. Neoblast lineages arise as organogenesis begins and are required for construction of all major organ systems during embryogenesis. These subpopulations are continuously generated during adulthood, where they act as agents of tissue homeostasis and regeneration. DOI: http://dx.doi.org/10.7554/eLife.21052.001 PMID:28072387

Acral melanocytic lesions in the United States: Prevalence, awareness, and dermoscopic patterns in skin-of-color and non-Hispanic white patients.

PubMed

Madankumar, Reshmi; Gumaste, Priyanka V; Martires, Kathryn; Schaffer, Panta R; Choudhary, Sonal; Falto-Aizpurua, Leyre; Arora, Harleen; Kallis, Penelope J; Patel, Shailee; Damanpour, Shadi; Sanchez, Margaret I; Yin, Natalie; Chan, Aegean; Sanchez, Miguel; Polsky, David; Kanavy, Holly; Grichnik, James M; Stein, Jennifer A

2016-04-01

Acral lentiginous melanoma has increased mortality compared with other melanoma subtypes and disproportionately affects ethnic minorities. Acral melanocytic lesions have not been well studied in diverse populations of the United States. We sought to assess the prevalence, awareness, and dermoscopic patterns of acral melanocytic lesions in skin-of-color and non-Hispanic white patients. We prospectively examined the palms and soles of 1052 patients presenting to dermatology clinics in New York, NY, and Miami, FL, from October 2013 to April 2015. Acral melanocytic lesions were observed in 36% of our cohort. Skin-of-color patients were more likely to have acral melanocytic lesions than non-Hispanic white patients (P < .01). Acral melanocytic lesions correlated with increased mole counts, particularly on non-Hispanic white patients. The majority of lesions demonstrated benign dermoscopic patterns. We observed 2 lesions with the parallel ridge pattern in our cohort, both found to be atypical nevi on biopsy specimen. Patients often lacked awareness of the presence of their lesions. Interobserver variability in assessing dermoscopic patterns is a limitation. Melanocytic lesions of the palms and soles are common, particularly in a cohort of multiple ethnicities from the United States. Dermoscopy of acral lesions is an important clinical tool for diagnosis and management of these lesions. Copyright © 2015 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

Loss of Oca2 disrupts the unfolded protein response and increases resistance to endoplasmic reticulum stress in melanocytes

PubMed Central

Cheng, Tsing; Orlow, Seth J.; Manga, Prashiela

2013-01-01

Summary Accumulation of proteins in the endoplasmic reticulum (ER) typically induces stress and initiates the unfolded protein response (UPR) to facilitate recovery. If homeostasis is not restored, apoptosis is induced. However, adaptation to chronic UPR activation can increase resistance to subsequent acute ER stress. We therefore investigated adaptive mechanisms in Oculocutaneous albinism type 2 (Oca2)-null melanocytes where UPR signaling is arrested despite continued tyrosinase accumulation leading to resistance to the chemical ER stressor thapsigargin. Although thapsigargin triggers UPR activation, instead of Perk-mediated phosphorylation of eIF2α, in Oca2-null melanocytes, eIF2α was rapidly dephosphorylated upon treatment. Dephosphorylation was mediated by the Gadd34-PP1α phosphatase complex. Gadd34-complex inhibition blocked eIF2α dephosphorylation and significantly increased Oca2-null melanocyte sensitivity to thapsigargin. Thus, Oca2-null melanocytes adapt to acute ER stress by disruption of proapoptotic Perk signaling, which promotes cell survival. This is the first study to demonstrate rapid eIF2α dephosphorylation as an adaptive mechanism to ER stress. PMID:23962237

Enhancer of polycomb coordinates multiple signaling pathways to promote both cyst and germline stem cell differentiation in the Drosophila adult testis

PubMed Central

Feng, Lijuan; Shi, Zhen; Chen, Xin

2017-01-01

Stem cells reside in a particular microenvironment known as a niche. The interaction between extrinsic cues originating from the niche and intrinsic factors in stem cells determines their identity and activity. Maintenance of stem cell identity and stem cell self-renewal are known to be controlled by chromatin factors. Herein, we use the Drosophila adult testis which has two adult stem cell lineages, the germline stem cell (GSC) lineage and the cyst stem cell (CySC) lineage, to study how chromatin factors regulate stem cell differentiation. We find that the chromatin factor Enhancer of Polycomb [E(Pc)] acts in the CySC lineage to negatively control transcription of genes associated with multiple signaling pathways, including JAK-STAT and EGF, to promote cellular differentiation in the CySC lineage. E(Pc) also has a non-cell-autonomous role in regulating GSC lineage differentiation. When E(Pc) is specifically inactivated in the CySC lineage, defects occur in both germ cell differentiation and maintenance of germline identity. Furthermore, compromising Tip60 histone acetyltransferase activity in the CySC lineage recapitulates loss-of-function phenotypes of E(Pc), suggesting that Tip60 and E(Pc) act together, consistent with published biochemical data. In summary, our results demonstrate that E(Pc) plays a central role in coordinating differentiation between the two adult stem cell lineages in Drosophila testes. PMID:28196077

A case of melanocytic cervical adenosquamous carcinoma complicated with Cushing's syndrome.

PubMed

Chen, Y; Zhang, Y; Wang, L; Yang, X

2017-01-01

To date, cervical carcinoma complicated with Cushing's syndrome were all diagnosed as small cell carcinoma histo- logically, but not adenosquamous carcinoma. Here the authors present the diagnosis, management, and prognosis of a case of melanocytic cervical adenosquamous carcinoma complicated with Cushing's syndrome. A 28-year-old woman was admitted with the chief complaint of post-coital bleeding for one month. Gynecological examination revealed a nodular yellowish-pigmented vegetation (6x5 cm) on the cervix. Laboratory findings proved the diagnosis of Cushing's syndrome. Histopathological diagnosis showed the adenosquamous carcinoma with melanoma differentiation. Immunohistochemical stainings for melanoma A and anti- adrenocorticotropic hormone (ACTH) were positive in the majority of the tumor cells, which indicated that this melanocytic cervical carcinoma lesion was the source of ectopic ACTH production resulting in Cushing's syndrome. This is a unique case of a rare type of cervical carcinoma.

Multimodal imaging of bilateral diffuse uveal melanocytic proliferation associated with an iris mass lesion.

PubMed

Naysan, Jonathan; Pang, Claudine E; Klein, Robert W; Freund, K Bailey

2016-01-01

Bilateral diffuse uveal melanocytic proliferation (BDUMP) is a rare, paraneoplastic syndrome characterized by bilateral painless visual loss and proliferation of choroidal melanocytes in association with an underlying systemic malignancy. We report a case of bilateral diffuse uveal melanocytic proliferation associated with an underlying gynecological malignancy that also features the infrequent finding of an iris mass lesion, using multimodal imaging including ultra-widefield imaging, spectral domain and swept-source optical coherence tomography. A 59-year-old white female with a prior history of gynecological malignancy in remission presented with progressive bilateral visual loss over several weeks. The patient was noted to have a focal iris mass lesion in her right eye. Ultra-widefield color fundus photography showed a characteristic bilateral 'giraffe pattern' of pigmentary changes extending into the periphery as well as multiple discrete deeply pigmented lesions. Ultra-widefield autofluorescence was useful for visualizing the full extent of involvement. Indocyanine green angiography helped to demarcate the discrete pigmented choroidal lesions. Swept-source OCT clearly delineated the alternating zones of retinal pigment epithelium (RPE) thickening and RPE loss, as well as the prominent choroidal infiltration and thickening. BDUMP is an important diagnosis to consider in the presence of multiple discrete melanocytic choroidal lesions, diffuse choroidal thickening, characteristic RPE changes, iris mass lesions and exudative retinal detachment. Ultra-widefield imaging may demonstrate more extensive lesions than that detected on clinical examination or standard field imaging. Imaging with SS-OCT shows choroidal and RPE characteristics that correlate well with known histopathology of this entity.

Discrimination of Dysplastic Nevi from Common Melanocytic Nevi by Cellular and Molecular Criteria.

PubMed

Mitsui, Hiroshi; Kiecker, Felix; Shemer, Avner; Cannizzaro, Maria Vittoria; Wang, Claire Q F; Gulati, Nicholas; Ohmatsu, Hanako; Shah, Kejal R; Gilleaudeau, Patricia; Sullivan-Whalen, Mary; Cueto, Inna; McNutt, Neil Scott; Suárez-Fariñas, Mayte; Krueger, James G

2016-10-01

Dysplastic nevi (DNs), also known as Clark's nevi or atypical moles, are distinguished from common melanocytic nevi by variegation in pigmentation and clinical appearance, as well as differences in tissue patterning. However, cellular and molecular differences between DNs and common melanocytic nevi are not completely understood. Using cDNA microarray, quantitative RT-PCR, and immunohistochemistry, we molecularly characterized DNs and analyzed the difference between DNs and common melanocytic nevi. A total of 111 probesets (91 annotated genes, fold change > 2.0 and false discovery rate < 0.25) were differentially expressed between the two lesions. An unexpected finding in DNs was altered differentiation and activation of epidermal keratinocytes with increased expression of hair follicle-related molecules (keratin 25, trichohyalin, ribonuclease, RNase A family, 7) and inflammation-related molecules (S100A7, S100A8) at both genomic and protein levels. The immune microenvironment of DNs was characterized by an increase of T helper type 1 (IFNγ) and T helper type 2 (IL13) cytokines as well as an upregulation of oncostatin M and CXCL1. DUSP3, which regulates cellular senescence, was identified as one of the disease discriminative genes between DNs and common melanocytic nevi by three independent statistical approaches and its altered expression was confirmed by immunohistochemistry. The molecular and cellular changes in which the epidermal-melanin unit undergoes follicular differentiation as well as upregulation of defined cytokines could drive complex immune, epidermal, and pigmentary alterations. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Adult stem cell theory of the multi-stage, multi-mechanism theory of carcinogenesis: role of inflammation on the promotion of initiated stem cells.

PubMed

Trosko, James E; Tai, Mei-Hui

2006-01-01

Inflammation, induced by microbial agents, radiation, endogenous or exogenous chemicals, has been associated with chronic diseases, including cancer. Since carcinogenesis has been characterized as consisting of the 'initiation', 'promotion' and 'progression' phases, the inflammatory process could affect any or all three phases. The stem cell theory of carcinogenesis has been given a revival, in that isolated human adult stem cells have been isolated and shown to be 'targets' for neoplastic transformation. Oct4, a transcription factor, has been associated with adult stem cells, as well as their immortalized and tumorigenic derivatives, but not with the normal differentiated daughters. These data are consistent with the stem cell theory of carcinogenesis. In addition, Gap Junctional Intercellular Communication (GJIC) seems to play a major role in cell growth. Inhibition of GJIC by non-genotoxic chemicals or various oncogenes seems to be the mechanism for the tumor promotion and progression phases of carcinogenesis. Many of the toxins, synthetic non-genotoxicants, and endogenous inflammatory factors have been shown to inhibit GJIC and act as tumor promoters. The inhibition of GJIC might be the mechanism by which the inflammatory process affects cancer and that to intervene during tumor promotion with anti-inflammatory factors might be the most efficacious anti-cancer strategy.

Potential for a pluripotent adult stem cell treatment for acute radiation sickness

PubMed Central

Rodgerson, Denis O; Reidenberg, Bruce E; Harris, Alan G; Pecora, Andrew L

2012-01-01

Accidental radiation exposure and the threat of deliberate radiation exposure have been in the news and are a public health concern. Experience with acute radiation sickness has been gathered from atomic blast survivors of Hiroshima and Nagasaki and from civilian nuclear accidents as well as experience gained during the development of radiation therapy for cancer. This paper reviews the medical treatment reports relevant to acute radiation sickness among the survivors of atomic weapons at Hiroshima and Nagasaki, among the victims of Chernobyl, and the two cases described so far from the Fukushima Dai-Ichi disaster. The data supporting the use of hematopoietic stem cell transplantation and the new efforts to expand stem cell populations ex vivo for infusion to treat bone marrow failure are reviewed. Hematopoietic stem cells derived from bone marrow or blood have a broad ability to repair and replace radiation induced damaged blood and immune cell production and may promote blood vessel formation and tissue repair. Additionally, a constituent of bone marrow-derived, adult pluripotent stem cells, very small embryonic like stem cells, are highly resistant to ionizing radiation and appear capable of regenerating radiation damaged tissue including skin, gut and lung. PMID:24520532

Melanocyte response to gravitational stress: an overview with a focus on the role of cyclic nucleotides

NASA Astrophysics Data System (ADS)

Ivanova, Krassimira; Tsiockas, Wasiliki; Eiermann, Peter; Hauslage, Jens; Hemmersbach, Ruth; Block, Ingrid; Gerzer, Rupert

Human melanocytes are responsible for skin pigmentation by synthesizing the pigment melanin. A well known modulator of melanogenesis is the second messenger adenosine 3',5'-cyclic monophos-phate (cAMP). It has also been reported that the nitric oxide (NO)/soluble guanylyl cyclase (sGC)/guanosine 3',5'-cyclic monophosphate (cGMP) pathway is involved in UVB-induced melanogenesis. Melanin acts as a scavenger for free radicals during oxidative stress, but it may additionally act as a photosensitizer that generates active oxygen species upon UV radiation, which may initiate hypopigmentary disorders (e.g., vitiligo) as well as UV-induced oncogene cell transformation. Melanoma, a deadly skin cancer which arises from transformed melanocytes, is characterized by a resistance to chemotherapy. In our studies we were able to show that hu-man melanocytic cells differentially respond to gravitational stress. Hypergravity (up to 5 g for 24 h) stimulated cGMP efflux in cultured human melanocytes and non-metastatic melanoma cells, but not in metastatic phenotypes under the conditions of limited degradation [e.g., in the presence of phosphodiesterase (PDE) inhibitors] or stimulated synthesis of cGMP [e.g., by NO donors, but not natriuretic peptides], whereas cellular proliferation and morphology were not altered. Interestingly, long-term exposure to hypergravity stimulated an increase in both intra-cellular as well as extracellular cAMP levels as well as melanogenesis in pigmented melanocytes and non-metastatic melanoma cells. As some cAMP-PDEs are regulated by cGMP, it seems that the hypergravity-induced alteration of melanocyte pigmentation could be a result of a cross-talk between these two cyclic nucleotides. Hypergravity induced further an increase in the mRNA and protein levels of the selective cGMP and cAMP exporters, the multidrug resistance proteins (MRP) 4 and 5 -but not 8 -, whereas simulated microgravity (up to 1.21x10-2 g for 24 h) -provided by a fast-rotating clinostat

Switching roles: the functional plasticity of adult tissue stem cells

PubMed Central

Wabik, Agnieszka; Jones, Philip H

2015-01-01

Adult organisms have to adapt to survive, and the same is true for their tissues. Rates and types of cell production must be rapidly and reversibly adjusted to meet tissue demands in response to both local and systemic challenges. Recent work reveals how stem cell (SC) populations meet these requirements by switching between functional states tuned to homoeostasis or regeneration. This plasticity extends to differentiating cells, which are capable of reverting to SCs after injury. The concept of the niche, the micro-environment that sustains and regulates stem cells, is broadening, with a new appreciation of the role of physical factors and hormonal signals. Here, we review different functions of SCs, the cellular mechanisms that underlie them and the signals that bias the fate of SCs as they switch between roles. PMID:25812989

Adult Human Nasal Mesenchymal-Like Stem Cells Restore Cochlear Spiral Ganglion Neurons After Experimental Lesion

PubMed Central

Bas, Esperanza; Van De Water, Thomas R.; Lumbreras, Vicente; Rajguru, Suhrud; Goss, Garrett; Hare, Joshua M.

2014-01-01

A loss of sensory hair cells or spiral ganglion neurons from the inner ear causes deafness, affecting millions of people. Currently, there is no effective therapy to repair the inner ear sensory structures in humans. Cochlear implantation can restore input, but only if auditory neurons remain intact. Efforts to develop stem cell-based treatments for deafness have demonstrated progress, most notably utilizing embryonic-derived cells. In an effort to bypass limitations of embryonic or induced pluripotent stem cells that may impede the translation to clinical applications, we sought to utilize an alternative cell source. Here, we show that adult human mesenchymal-like stem cells (MSCs) obtained from nasal tissue can repair spiral ganglion loss in experimentally lesioned cochlear cultures from neonatal rats. Stem cells engraft into gentamicin-lesioned organotypic cultures and orchestrate the restoration of the spiral ganglion neuronal population, involving both direct neuronal differentiation and secondary effects on endogenous cells. As a physiologic assay, nasal MSC-derived cells engrafted into lesioned spiral ganglia demonstrate responses to infrared laser stimulus that are consistent with those typical of excitable cells. The addition of a pharmacologic activator of the canonical Wnt/β-catenin pathway concurrent with stem cell treatment promoted robust neuronal differentiation. The availability of an effective adult autologous cell source for inner ear tissue repair should contribute to efforts to translate cell-based strategies to the clinic. PMID:24172073

Epithelial-mesenchymal transition transcription factors control pluripotent adult stem cell migration in vivo in planarians

PubMed Central

Abnave, Prasad; Aboukhatwa, Ellen; Kosaka, Nobuyoshi; Thompson, James; Hill, Mark A.

2017-01-01

Migration of stem cells underpins the physiology of metazoan animals. For tissues to be maintained, stem cells and their progeny must migrate and differentiate in the correct positions. This need is even more acute after tissue damage by wounding or pathogenic infection. Inappropriate migration also underpins metastasis. Despite this, few mechanistic studies address stem cell migration during repair or homeostasis in adult tissues. Here, we present a shielded X-ray irradiation assay that allows us to follow stem cell migration in planarians. We demonstrate the use of this system to study the molecular control of stem cell migration and show that snail-1, snail-2 and zeb-1 EMT transcription factor homologs are necessary for cell migration to wound sites and for the establishment of migratory cell morphology. We also observed that stem cells undergo homeostatic migration to anterior regions that lack local stem cells, in the absence of injury, maintaining tissue homeostasis. This requires the polarity determinant notum. Our work establishes planarians as a suitable model for further in-depth study of the processes controlling stem cell migration in vivo. PMID:28893948

Relapsing tumefactive lesion in an adult with medulloblastoma previously treated with chemoradiotherapy and stem cell transplant.

PubMed

Mahta, Ali; Qu, Yan; Nastic, Denis; Sundstrom, Maria; Kim, Ryan Y; Saria, Marlon; Santagata, Sandro; Kesari, Santosh

2012-04-01

Herein, we present an adult case of medulloblastoma who received chemotherapy, radiation therapy and stem cell transplantation, and underwent multiple surgical resections for what were thought to be recurrences; however pathology confirmed a diagnosis of relapsing tumefactive lesions. This phenomenon seems to be a consequence of stem cell transplantation rather than a simple radiation treatment effect.

Congenital melanocytic nevus: two clinicopathological forms.

PubMed

Magaña, Mario; Sánchez-Romero, Elizabeth; Magaña, Pablo; Beck-Magaña, Andrés; Magaña-Lozano, Mario

2015-01-01

Congenital melanocytic nevus (CMN) is a hamartomatous disease for which many attempts at classification have been proposed. This disease is relevant not only because of its functional and esthetic implications but also because it is a well-documented precursor to malignant melanoma. We performed a clinical and pathological prospective study of 200 cases of CMN and were able to identify 2 different forms of CMN, each one with biological, clinical, and histopathological features and criteria that are consistent and repeatable. We propose to name them types I and II. Type I CMN is the most common, usually, if not always, a single lesion, it consists of a plaque that involves only 1 anatomic region and does not go beyond it; type I CNM grows in proportion to the growth of the child, melanoma rarely develops from it, and when it does it usually arises at the dermoepidermal junction. Its histopathology shows cords, strands, nests, and single units of melanocytes spreading between collagen bundles only in the dermis and frequently the epidermis too, but without trespassing to the hypodermis, that is, it is superficial. Type II CMN is always made up of many lesions, one of them being very large and surrounded by many lesions; histopathologically, it involves not only the skin but also deeper structures, sometimes bone and central nervous system; therefore, it is deep; when melanoma develops, it does in the dermal component and usually from the largest plaque. This type of CMN is the one that develops neurocutaneous melanocytosis. This system is not only easy and logical but it also has biologic advantages and the clinical-pathological correlation and criteria are repeatable by clinicians and pathologists.

Long-term outcomes of allogeneic haematopoietic stem cell transplantation for adult cerebral X-linked adrenoleukodystrophy.

PubMed

Kühl, Jörn-Sven; Suarez, Felipe; Gillett, Godfrey T; Hemmati, Philipp G; Snowden, John A; Stadler, Michael; Vuong, Giang L; Aubourg, Patrick; Köhler, Wolfgang; Arnold, Renate

2017-04-01

The adult cerebral inflammatory form of X-linked adrenoleukodystrophy is a rapidly progressive neurodegenerative disease, as devastating as childhood cerebral adrenoleukodystrophy. Allogeneic haematopoietic stem cell transplantation has been demonstrated to provide long-term neurological benefits for boys with the childhood cerebral form, but results in adults are sparse and inconclusive. We analysed data from 14 adult males with adult cerebral adrenoleukodystrophy treated with allogeneic haematopoietic stem cell transplantation on a compassionate basis in four European centres. All presented with cerebral demyelinating lesions and gadolinium enhancement. Median age at diagnosis of adult cerebral adrenoleukodystrophy was 33 years (range 21-48 years). In addition to cerebral inflammation, five patients had established severe motor disability from adrenomyeloneuropathy affecting only the spinal cord and peripheral nerves (Expanded Disability Status Scale score ≥ 6). Eight patients survived (estimated survival 57 ± 13%) with a median follow-up of 65 months (minimum 38 months). Death was directly transplant-/infection-related (n = 3), due to primary disease progression in advanced adult cerebral adrenoleukodystrophy (n = 1), or secondary disease progression (n = 2) after transient multi-organ failure or non-engraftment. Specific complications during stem cell transplantation included deterioration of motor and bladder functions (n = 12) as well as behavioural changes (n = 8). Arrest of progressive cerebral demyelination and prevention of severe loss of neurocognition was achieved in all eight survivors, but deterioration of motor function occurred in the majority (n = 5). Limited motor dysfunction (Expanded Disability Status Scale score < 6) prior to transplantation was associated with significantly improved survival [78 ± 14% (n = 9) versus 20 ± 18%(n = 5); P < 0.05] and maintenance of ambulation (Expanded Disability Status Scale score < 7) post-transplant (78

Tissue Inhibitor of Metalloproteinase 1 Expression Associated with Gene Demethylation Confers Anoikis Resistance in Early Phases of Melanocyte Malignant Transformation1

PubMed Central

Ricca, Tatiana I; Liang, Gangning; Suenaga, Ana Paula M; Han, Sang W; Jones, Peter A; Jasiulionis, Miriam G

2009-01-01

Although anoikis resistance has been considered a hallmark of malignant phenotype, the causal relation between neoplastic transformation and anchorage-independent growth remains undefined. We developed an experimental model of murine melanocyte malignant transformation, where a melanocyte lineage (melan-a) was submitted to sequential cycles of anchorage blockade, resulting in progressive morphologic alterations, and malignant transformation. Throughout this process, cells corresponding to premalignant melanocytes and melanoma cell lines were established and show progressive anoikis resistance and increased expression of Timp1. In melan-a melanocytes, Timp1 expression is suppressed by DNA methylation as indicated by its reexpression after 5-aza-2′-deoxycytidine treatment. Methylation-sensitive single-nucleotide primer extension analysis showed increased demethylation in Timp1 in parallel with its expression along malignant transformation. Interestingly, TIMP1 expression has already been related with negative prognosis in some human cancers. Although described as a MMP inhibitor, this protein has been associated with apoptosis resistance in different cell types. Melan-a cells overexpressing Timp1 showed increased survival in suspension but were unable to form tumors in vivo, whereas Timp1-overexpressing melanoma cells showed reduced latency time for tumor appearance and increased metastatic potential. Here, we demonstrated for the first time an increment in Timp1 expression since the early phases of melanocyte malignant transformation, associated to a progressive gene demethylation, which confers anoikis resistance. In this way, Timp1 might be considered as a valued marker for melanocyte malignant transformation. PMID:19956395

Quiescent gastric stem cells maintain the adult Drosophila stomach.

PubMed

Strand, Marie; Micchelli, Craig A

2011-10-25

The adult Drosophila copper cell region or "stomach" is a highly acidic compartment of the midgut with pH < 3. In this region, a specialized group of acid-secreting cells similar to mammalian gastric parietal cells has been identified by a unique ultrastructure and by copper-metallothionein fluorescence. However, the homeostatic mechanism maintaining the acid-secreting "copper cells" of the adult midgut has not been examined. Here, we combine cell lineage tracing and genetic analysis to investigate the mechanism by which the gastric epithelium is maintained. Our investigation shows that a molecularly identifiable population of multipotent, self-renewing gastric stem cells (GSSCs) produces the acid-secreting copper cells, interstitial cells, and enteroendocrine cells of the stomach. Our assays demonstrate that GSSCs are largely quiescent but can be induced to regenerate the gastric epithelium in response to environmental challenge. Finally, genetic analysis reveals that adult GSSC maintenance depends on Wnt signaling. Characterization of the GSSC lineage in Drosophila, with striking similarities to mammals, will advance the study of both homeostatic and pathogenic processes in the stomach.

Axonal Control of the Adult Neural Stem Cell Niche

PubMed Central

Tong, Cheuk Ka; Chen, Jiadong; Cebrián-Silla, Arantxa; Mirzadeh, Zaman; Obernier, Kirsten; Guinto, Cristina D.; Tecott, Laurence H.; García-Verdugo, Jose Manuel; Kriegstein, Arnold; Alvarez-Buylla, Arturo

2014-01-01

SUMMARY The ventricular-subventricular zone (V-SVZ) is an extensive germinal niche containing neural stem cells (NSC) in the walls of the lateral ventricles of the adult brain. How the adult brain’s neural activity influences the behavior of adult NSCs remains largely unknown. We show that serotonergic (5HT) axons originating from a small group of neurons in the raphe form an extensive plexus on most of the ventricular walls. Electron microscopy revealed intimate contacts between 5HT axons and NSCs (B1) or ependymal cells (E1) and these cells were labeled by a transsynaptic viral tracer injected into the raphe. B1 cells express the 5HT receptors 2C and 5A. Electrophysiology showed that activation of these receptors in B1 cells induced small inward currents. Intraventricular infusion of 5HT2C agonist or antagonist increased or decreased V-SVZ proliferation, respectively. These results indicate that supraependymal 5HT axons directly interact with NSCs to regulate neurogenesis via 5HT2C. PMID:24561083

Histopathologic Findings of Cutaneous Hyperpigmentation in Addison Disease and Immunostain of the Melanocytic Population.

PubMed

Fernandez-Flores, Angel; Cassarino, David S

2017-12-01

The histopathological features of cutaneous hyperpigmentation in Addison disease have very occasionally been reported, and they include acanthosis, hyperkeratosis, focal parakeratosis, spongiosis, superficial perivascular lymphocytic infiltrate, basal melanin hyperpigmentation, and superficial dermal melanophages. We present a study on 2 biopsies from the arm and the thigh in a 77-year-old woman with a long clinical history of Addison disease as well as senile purpura and alopecia of female pattern. The patient presented diffuse hyperpigmentation of the skin, more pronounced on her face, and left upper forehead. The skin biopsies showed no remarkable dermal inflammatory infiltrate with melanocytic hyperpigmentation of the basal layer of the epidermis as well as a mild amount of melanophages in the papillary dermis. In addition, we found lipofuscin in the luminal pole of the secretory epithelium of the eccrine glands. In the perieccrine areas, there was Perls-positive pigment in the cytoplasm of macrophages most likely related to the senile purpura. An immunohistochemical study with Melan-A showed a melanocyte/keratinocyte ratio of 1:20 (5%) in the arm and of less than 1:50 (only 2 melanocytes in the whole section; <2%) in the thigh.

FGF21 regulates melanogenesis in alpaca melanocytes via ERK1/2-mediated MITF downregulation.

PubMed

Wang, Ruiwei; Chen, Tianzhi; Zhao, Bingling; Fan, Ruiwen; Ji, Kaiyuan; Yu, Xiuju; Wang, Xianjun; Dong, Changsheng

2017-08-19

Fibroblast growth factor 21 (FGF21) is known as a metabolic regulator to regulate the metabolism of glucose and lipids. However, the underlying mechanism of FGF21 on melanin synthesis remains unknown. Therefore, the current study investigates the effect of FGF21 on melanogenesis in alpaca melanocytes. We transfected the FGF21 into alpaca melanocytes, then detected the melanin contents, protein and mRNA levels of pigmentation-related genes in order to determine the melanogenesis-regulating pathway of FGF21. The results showed that FGF21 overexpression suppressed melanogenesis and decreased the expression of the major target genes termed microphthalmia-associated transcription factor (MITF) and its downstream genes, including tyrosinase (TYR) and tyrosinase-related protein 2 (TRP2). However FGF21 increased the expression of phospho-extracellular signal-regulated kinase (p-Erk1/2). In contrast, FGF21-siRNA, a small interference RNA mediating FGF21 silencing, abolished the inhibition of melanogenesis. Altogether, FGF21 may decrease melanogenesis in alpaca melanocytes via ERK activation and subsequent MITF downregulation, which is then followed by the suppression of melanogenic enzymes and melanin production. Copyright © 2017. Published by Elsevier Inc.

Adult stem cell lineage tracing and deep tissue imaging

PubMed Central

Fink, Juergen; Andersson-Rolf, Amanda; Koo, Bon-Kyoung

2015-01-01

Lineage tracing is a widely used method for understanding cellular dynamics in multicellular organisms during processes such as development, adult tissue maintenance, injury repair and tumorigenesis. Advances in tracing or tracking methods, from light microscopy-based live cell tracking to fluorescent label-tracing with two-photon microscopy, together with emerging tissue clearing strategies and intravital imaging approaches have enabled scientists to decipher adult stem and progenitor cell properties in various tissues and in a wide variety of biological processes. Although technical advances have enabled time-controlled genetic labeling and simultaneous live imaging, a number of obstacles still need to be overcome. In this review, we aim to provide an in-depth description of the traditional use of lineage tracing as well as current strategies and upcoming new methods of labeling and imaging. [BMB Reports 2015; 48(12): 655-667] PMID:26634741

Loss of Oca2 disrupts the unfolded protein response and increases resistance to endoplasmic reticulum stress in melanocytes.

PubMed

Cheng, Tsing; Orlow, Seth J; Manga, Prashiela

2013-11-01

Accumulation of proteins in the endoplasmic reticulum (ER) typically induces stress and initiates the unfolded protein response (UPR) to facilitate recovery. If homeostasis is not restored, apoptosis is induced. However, adaptation to chronic UPR activation can increase resistance to subsequent acute ER stress. We therefore investigated adaptive mechanisms in Oculocutaneous albinism type 2 (Oca2)-null melanocytes where UPR signaling is arrested despite continued tyrosinase accumulation leading to resistance to the chemical ER stressor thapsigargin. Although thapsigargin triggers UPR activation, instead of Perk-mediated phosphorylation of eIF2α, in Oca2-null melanocytes, eIF2α was rapidly dephosphorylated upon treatment. Dephosphorylation was mediated by the Gadd34-PP1α phosphatase complex. Gadd34-complex inhibition blocked eIF2α dephosphorylation and significantly increased Oca2-null melanocyte sensitivity to thapsigargin. Thus, Oca2-null melanocytes adapt to acute ER stress by disruption of pro-apoptotic Perk signaling, which promotes cell survival. This is the first study to demonstrate rapid eIF2α dephosphorylation as an adaptive mechanism to ER stress. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

High Throughput, High Content Screening for Novel Pigmentation Regulators Using a Keratinocyte/Melanocyte Co-culture System

PubMed Central

Lee, Ju Hee; Chen, Hongxiang; Kolev, Vihren; Aull, Katherine H.; Jung, Inhee; Wang, Jun; Miyamoto, Shoko; Hosoi, Junichi; Mandinova, Anna; Fisher, David E.

2014-01-01

Skin pigmentation is a complex process including melanogenesis within melanocytes and melanin transfer to the keratinocytes. To develop a comprehensive screening method for novel pigmentation regulators, we used immortalized melanocytes and keratinocytes in co-culture to screen large numbers of compounds. High-throughput screening plates were subjected to digital automated microscopy to quantify the pigmentation via brightfield microscopy. Compounds with pigment suppression were secondarily tested for their effects on expression of MITF and several pigment regulatory genes, and further validated in terms of non-toxicity to keratinocytes/melanocytes and dose dependent activity. The results demonstrate a high-throughput, high-content screening approach, which is applicable to the analysis of large chemical libraries using a co-culture system. We identified candidate pigmentation inhibitors from 4,000 screened compounds including zoxazolamine, 3-methoxycatechol, and alpha-mangostin, which were also shown to modulate expression of MITF and several key pigmentation factors, and are worthy of further evaluation for potential translation to clinical use. PMID:24438532

Giant melanocytic nevus with malignant melanoma: a rare disorder in a black African child.

PubMed

Katibi, Oludolapo Sherifat; Ogunbiyi, Adebola; Brown, Biobele Jotham; Adeyemi, Oyedeji Oladele

2014-10-01

Giant congenital melanocytic nevus (GCMN) is rare in babies of African descent. Unfortunately, it has an increased potential for malignant transformation. A 3-year-old female child presented with a 6-month history of multiple nodules on an existing giant congenital melanocytic nevus and swelling in the right axilla of four weeks duration. Skin biopsy of the nodular skin lesions was in keeping with a metastatic malignant melanoma (Clark stage 4). She completed a full course of chemotherapy but subsequently died four months after presentation. Patients with large GCMN should be counseled and followed up appropriately to improve and prolong life. © 2014 The International Society of Dermatology.

Adult Palatum as a Novel Source of Neural Crest-Related Stem Cells

PubMed Central

Widera, Darius; Zander, Christin; Heidbreder, Meike; Kasperek, Yvonne; Noll, Thomas; Seitz, Oliver; Saldamli, Belma; Sudhoff, Holger; Sader, Robert; Kaltschmidt, Christian; Kaltschmidt, Barbara

2009-01-01

Somatic neural and neural crest stem cells are promising sources for cellular therapy of several neurodegenerative diseases. However, because of practical considerations such as inadequate accessibility of the source material, the application of neural crest stem cells is strictly limited. The secondary palate is a highly regenerative and heavily innervated tissue, which develops embryonically under direct contribution of neural crest cells. Here, we describe for the first time the presence of nestin-positive neural crest-related stem cells within Meissner corpuscles and Merkel cell-neurite complexes located in the hard palate of adult Wistar rats. After isolation, palatal neural crest-related stem cells (pNC-SCs) were cultivated in the presence of epidermal growth factor and fibroblast growth factor under serum-free conditions, resulting in large amounts of neurospheres. We used immunocytochemical techniques and reverse transcriptase-polymerase chain reaction to assess the expression profile of pNC-SCs. In addition to the expression of neural crest stem cell markers such as Nestin, Sox2, and p75, we detected the expression of Klf4, Oct4, and c-Myc. pNC-SCs differentiated efficiently into neuronal and glial cells. Finally, we investigated the potential expression of stemness markers within the human palate. We identified expression of stem cell markers nestin and CD133 and the transcription factors needed for reprogramming of somatic cells into pluripotent cells: Sox2, Oct4, Klf4, and c-Myc. These data show that cells isolated from palatal rugae form neurospheres, are highly plastic, and express neural crest stem cell markers. In addition, pNC-SCs may have the ability to differentiate into functional neurons and glial cells, serving as a starting point for therapeutic studies. Stem Cells 2009;27:1899–1910 PMID:19544446

Mining Gene Expression Signature for the Detection of Pre-Malignant Melanocytes and Early Melanomas with Risk for Metastasis

PubMed Central

de Souza, Camila Ferreira; Xander, Patrícia; Monteiro, Ana Carolina; Silva, Amanda Gonçalves dos Santos; da Silva, Débora Castanheira Pereira; Mai, Sabine; Bernardo, Viviane; Lopes, José Daniel; Jasiulionis, Miriam Galvonas

2012-01-01

Background Metastatic melanoma is a highly aggressive skin cancer and currently resistant to systemic therapy. Melanomas may involve genetic, epigenetic and metabolic abnormalities. Evidence is emerging that epigenetic changes might play a significant role in tumor cell plasticity and metastatic phenotype of melanoma cells. Principal findings In this study, we developed a systematic approach to identify genes implicated in melanoma progression. To do this, we used the Affymetrix GeneChip Arrays to screen 34,000 mouse transcripts in melan-a melanocytes, 4C pre-malignant melanocytes, 4C11− non-metastatic and 4C11+ metastatic melanoma cell lines. The genome-wide association studies revealed pathways commonly over-represented in the transition from immortalized to pre-malignant stage, and under-represented in the transition from non-metastatic to metastatic stage. Additionally, the treatment of cells with 10 µM 5-aza-2′-deoxycytidine (5AzaCdR) for 48 hours allowed us to identify genes differentially re-expressed at specific stages of melan-a malignant transformation. Treatment of human primary melanocytes with the demethylating agent 5AzaCdR in combination to the histone deacetylase inhibitor Trichostatin A (TSA) revealed changes on melanocyte morphology and gene expression which could be an indicator of epigenetic flexibility in normal melanocytes. Moreover, changes on gene expression recognized by affecting the melanocyte biology (NDRG2 and VDR), phenotype of metastatic melanoma cells (HSPB1 and SERPINE1) and response to cancer therapy (CTCF, NSD1 and SRC) were found when Mel-2 and/or Mel-3-derived patient metastases were exposed to 5AzaCdR plus TSA treatment. Hierarchical clustering and network analyses in a panel of five patient-derived metastatic melanoma cells showed gene interactions that have never been described in melanomas. Significance Despite the heterogeneity observed in melanomas, this study demonstrates the utility of our murine melanoma

Protection from UV light is an evolutionarily conserved feature of the haematopoietic niche

USGS Publications Warehouse

Kapp, Friedrich G.; Perlin, Julie R.; Hagedorn, Elliott J.; Gansner, John M.; Schwarz, Daniel E.; O'Connell, Lauren A.; Johnson, Nicholas; Amemiya, Chris; Fisher, David E.; Wolfle, Ute; Trompouki, Eirini; Niemeyer, Charlotte M.; Driever, Wolfgang; Zon, Leonard I.

2018-01-01

Haematopoietic stem and progenitor cells (HSPCs) require a specific microenvironment, the haematopoietic niche, which regulates HSPC behaviour. The location of this niche varies across species, but the evolutionary pressures that drive HSPCs to different microenvironments remain unknown. The niche is located in the bone marrow in adult mammals, whereas it is found in other locations in non-mammalian vertebrates, for example, in the kidney marrow in teleost fish. Here we show that a melanocyte umbrella above the kidney marrow protects HSPCs against ultraviolet light in zebrafish. Because mutants that lack melanocytes have normal steady-state haematopoiesis under standard laboratory conditions, we hypothesized that melanocytes above the stem cell niche protect HSPCs against ultraviolet-light-induced DNA damage. Indeed, after ultraviolet-light irradiation, unpigmented larvae show higher levels of DNA damage in HSPCs, as indicated by staining of cyclobutane pyrimidine dimers and have reduced numbers of HSPCs, as shown by cmyb (also known as myb) expression. The umbrella of melanocytes associated with the haematopoietic niche is highly evolutionarily conserved in aquatic animals, including the sea lamprey, a basal vertebrate. During the transition from an aquatic to a terrestrial environment, HSPCs relocated into the bone marrow, which is protected from ultraviolet light by the cortical bone around the marrow. Our studies reveal that melanocytes above the haematopoietic niche protect HSPCs from ultraviolet-light-induced DNA damage in aquatic vertebrates and suggest that during the transition to terrestrial life, ultraviolet light was an evolutionary pressure affecting the location of the haematopoietic niche.

Protection from UV light is an evolutionarily conserved feature of the haematopoietic niche.

PubMed

Kapp, Friedrich G; Perlin, Julie R; Hagedorn, Elliott J; Gansner, John M; Schwarz, Daniel E; O'Connell, Lauren A; Johnson, Nicholas S; Amemiya, Chris; Fisher, David E; Wölfle, Ute; Trompouki, Eirini; Niemeyer, Charlotte M; Driever, Wolfgang; Zon, Leonard I

2018-06-01

Haematopoietic stem and progenitor cells (HSPCs) require a specific microenvironment, the haematopoietic niche, which regulates HSPC behaviour 1,2 . The location of this niche varies across species, but the evolutionary pressures that drive HSPCs to different microenvironments remain unknown. The niche is located in the bone marrow in adult mammals, whereas it is found in other locations in non-mammalian vertebrates, for example, in the kidney marrow in teleost fish. Here we show that a melanocyte umbrella above the kidney marrow protects HSPCs against ultraviolet light in zebrafish. Because mutants that lack melanocytes have normal steady-state haematopoiesis under standard laboratory conditions, we hypothesized that melanocytes above the stem cell niche protect HSPCs against ultraviolet-light-induced DNA damage. Indeed, after ultraviolet-light irradiation, unpigmented larvae show higher levels of DNA damage in HSPCs, as indicated by staining of cyclobutane pyrimidine dimers and have reduced numbers of HSPCs, as shown by cmyb (also known as myb) expression. The umbrella of melanocytes associated with the haematopoietic niche is highly evolutionarily conserved in aquatic animals, including the sea lamprey, a basal vertebrate. During the transition from an aquatic to a terrestrial environment, HSPCs relocated into the bone marrow, which is protected from ultraviolet light by the cortical bone around the marrow. Our studies reveal that melanocytes above the haematopoietic niche protect HSPCs from ultraviolet-light-induced DNA damage in aquatic vertebrates and suggest that during the transition to terrestrial life, ultraviolet light was an evolutionary pressure affecting the location of the haematopoietic niche.

A signet-ring cell melanoma arising from a medium-sized congenital melanocytic nevus in an adult: A case report and literature review.

PubMed

Tajima, Shogo; Koda, Kenji

2015-07-01

Patients with congenital nevus, especially giant congenital melanocytic nevus (CMN) measuring >20 cm, are known to be at elevated risk of developing melanomas, especially during the first and second decades of life. Melanomas rarely develop in patients with small and medium-sized CMNs, but if they do, they occur during the fourth and fifth decades of life. We present a case of a rapidly enlarging signet-ring cell melanoma (over 3 months) that arose from a medium-sized CMN in a 57-year-old Japanese man. Only 11 other cases of signet-ring cell melanomas at the primary site have been reported. On the basis of morphology alone, it is difficult to diagnose a nodule appearing in a CMN as a signet-ring cell melanoma, because even a benign melanocytic nevus can appear as signet-ring cell morphology. Moreover, a rapidly growing proliferative nodule (PN) more often develops in a CMN than melanoma; PNs may at times exhibit enough atypia to be comparable to melanomas. In our case, loss of p16 expression in the melanoma distinguished it from the nevus cells and was helpful in making the correct diagnosis. Clinical information, such as the patient's age, was also useful in establishing the diagnosis. © 2015 Japanese Society of Pathology and Wiley Publishing Asia Pty Ltd.

Loss of 5-hydroxymethylcytosine correlates with increasing morphologic dysplasia in melanocytic tumors.

PubMed

Larson, Allison R; Dresser, Karen A; Zhan, Qian; Lezcano, Cecilia; Woda, Bruce A; Yosufi, Benafsha; Thompson, John F; Scolyer, Richard A; Mihm, Martin C; Shi, Yujiang G; Murphy, George F; Lian, Christine Guo

2014-07-01

DNA methylation is the most well-studied epigenetic modification in cancer biology. 5-hydroxymethylcytosine is an epigenetic mark that can be converted from 5-methylcytosine by the ten-eleven translocation gene family. We recently reported the loss of 5-hydroxymethylcytosine in melanoma compared with benign nevi and suggested that loss of this epigenetic marker is correlated with tumor virulence based on its association with a worse prognosis. In this study, we further characterize the immunoreactivity patterns of 5-hydroxymethylcytosine in the full spectrum of melanocytic lesions to further validate the potential practical application of this epigenetic marker. One hundred and seventy-five cases were evaluated: 18 benign nevi, 20 dysplastic nevi (10 low-grade and 10 high-grade lesions), 10 atypical Spitz nevi, 20 borderline tumors, 5 melanomas arising within nevi, and 102 primary melanomas. Progressive loss of 5-hydroxymethylcytosine from benign dermal nevi to high-grade dysplastic nevi to borderline melanocytic neoplasms to melanoma was observed. In addition, an analysis of the relationship of nuclear diameter with 5-hydroxymethylcytosine staining intensity within lesional cells revealed a significant correlation between larger nuclear diameter and decreased levels of 5-hydroxymethylcytosine. Furthermore, borderline lesions uniquely exhibited a diverse spectrum of staining of each individual case. This study further substantiates the association of 5-hydroxymethylcytosine loss with dysplastic cytomorphologic features and tumor progression and supports the classification of borderline lesions as a biologically distinct category of melanocytic lesions.

Loss of 5-hydroxymethylcytosine correlates with increasing morphologic dysplasia in melanocytic tumors

PubMed Central

Larson, Allison R.; Dresser, Karen; Zhan, Qian; Lezcano, Cecilia; Woda, Bruce A.; Yosufi, Benafsha; Thompson, John F.; Scolyer, Richard A.; Mihm, Martin C.; Shi, Yujiang G.; Murphy, George F.; Lian, Christine Guo

2013-01-01

DNA methylation is the most well studied epigenetic modification in cancer biology. 5-hydroxymethylcytosine is an epigenetic mark that can be converted from 5-methylcytosine by the ten-eleven translocation gene family. We recently reported the loss of 5-hydroxymethylcytosine in melanoma compared to benign nevi and suggested that loss of this epigenetic marker is correlated with tumor virulence based on its association with a worse prognosis. In this study we further characterize the immunoreactivity patterns of 5-hydroxymethylcytosine in the full spectrum of melanocytic lesions to further validate the potential practical application of this epigenetic marker. 175 cases were evaluated: 18 benign nevi, 20 dysplastic nevi (10 low-grade and 10 high-grade lesions), 10 atypical Spitz nevi, 20 borderline tumors, 5 melanomas arising within nevi, and 102 primary melanomas. Progressive loss of 5-hydroxymethylcytosine from benign dermal nevi to high-grade dysplastic nevi to borderline melanocytic neoplasms to melanoma was observed. In addition, an analysis of the relationship of nuclear diameter to 5-hydroxymethylcytosine staining intensity within lesional cells revealed a significant correlation between larger nuclear diameter and decreased levels of 5-hydroxymethylcytosine. Furthermore, borderline lesions uniquely exhibited a diverse spectrum of staining of each individual case. This study further substantiates the association of 5-hydroxymethylcytosine loss with dysplastic cytomorphologic features and tumor progression and supports the classification of borderline lesions as a biologically distinct category of melanocytic lesions. PMID:24390216

CD34+ Testicular Stromal Cells Support Long-Term Expansion of Embryonic and Adult Stem and Progenitor Cells

PubMed Central

Kim, Jiyeon; Seandel, Marco; Falciatori, Ilaria; Wen, Duancheng; Rafii, Shahin

2010-01-01

Stem cells reside in specialized microenvironments created by supporting stromal cells that orchestrate self-renewal and lineage-specific differentiation. However, the precise identity of the cellular and molecular pathways that support self-renewal of stem cells is not known. For example, long-term culture of prototypical stem cells, such as adult spermatogonial stem and progenitor cells (SPCs), in vitro has been impeded by the lack of an optimal stromal cell line that initiates and sustains proliferation of these cells. Indeed, current methods, including the use of mouse embryonic fibroblasts (MEFs), have not been efficient and have generally led to inconsistent results. Here, we report the establishment of a novel CD34-positive cell line, referred to as JK1, derived from mouse testicular stromal cells that not only facilitated long-term SPC culture but also allowed faithful generation of SPCs and multipotent stem cells. SPCs generated on JK1 maintained key features of germ line stem cells, including expression of PLZF, DAZL, and GCNA. Furthermore, these feeders also promoted the long-term cultivation of other types of primitive cells including multi-potent adult spermatogonial-derived stem cells, pluripotent murine embryonic stem cells, and embryonic germ cells derived from primordial germ cells. Stem cells could be passaged serially and still maintained expression of characteristic markers such as OCT4 and NANOG in vitro, as well as the ability to generate all three germ layers in vivo. These results indicate that the JK1 cell line is capable of promoting long-term culture of primitive cells. As such, this cell line allows for identification of stromal-derived factors that support long-term proliferation of various types of stem cells and constitutes a convenient alternative to other types of feeder layers. PMID:18669907

Long-Term Culture of Genome-Stable Bipotent Stem Cells from Adult Human Liver

PubMed Central

Huch, Meritxell; Gehart, Helmuth; van Boxtel, Ruben; Hamer, Karien; Blokzijl, Francis; Verstegen, Monique M.A.; Ellis, Ewa; van Wenum, Martien; Fuchs, Sabine A.; de Ligt, Joep; van de Wetering, Marc; Sasaki, Nobuo; Boers, Susanne J.; Kemperman, Hans; de Jonge, Jeroen; Ijzermans, Jan N.M.; Nieuwenhuis, Edward E.S.; Hoekstra, Ruurdtje; Strom, Stephen; Vries, Robert R.G.; van der Laan, Luc J.W.; Cuppen, Edwin; Clevers, Hans

2015-01-01

Summary Despite the enormous replication potential of the human liver, there are currently no culture systems available that sustain hepatocyte replication and/or function in vitro. We have shown previously that single mouse Lgr5+ liver stem cells can be expanded as epithelial organoids in vitro and can be differentiated into functional hepatocytes in vitro and in vivo. We now describe conditions allowing long-term expansion of adult bile duct-derived bipotent progenitor cells from human liver. The expanded cells are highly stable at the chromosome and structural level, while single base changes occur at very low rates. The cells can readily be converted into functional hepatocytes in vitro and upon transplantation in vivo. Organoids from α1-antitrypsin deficiency and Alagille syndrome patients mirror the in vivo pathology. Clonal long-term expansion of primary adult liver stem cells opens up experimental avenues for disease modeling, toxicology studies, regenerative medicine, and gene therapy. PMID:25533785

Thyroid Hormone-Induced Activation of Notch Signaling is Required for Adult Intestinal Stem Cell Development During Xenopus Laevis Metamorphosis.

PubMed

Hasebe, Takashi; Fujimoto, Kenta; Kajita, Mitsuko; Fu, Liezhen; Shi, Yun-Bo; Ishizuya-Oka, Atsuko

2017-04-01

In Xenopus laevis intestine during metamorphosis, the larval epithelial cells are removed by apoptosis, and the adult epithelial stem (AE) cells appear concomitantly. They proliferate and differentiate to form the adult epithelium (Ep). Thyroid hormone (TH) is well established to trigger this remodeling by regulating the expression of various genes including Notch receptor. To study the role of Notch signaling, we have analyzed the expression of its components, including the ligands (DLL and Jag), receptor (Notch), and targets (Hairy), in the metamorphosing intestine by real-time reverse transcription-polymerase chain reaction and in situ hybridization or immunohistochemistry. We show that they are up-regulated during both natural and TH-induced metamorphosis in a tissue-specific manner. Particularly, Hairy1 is specifically expressed in the AE cells. Moreover, up-regulation of Hairy1 and Hairy2b by TH was prevented by treating tadpoles with a γ-secretase inhibitor (GSI), which inhibits Notch signaling. More importantly, TH-induced up-regulation of LGR5, an adult intestinal stem cell marker, was suppressed by GSI treatment. Our results suggest that Notch signaling plays a role in stem cell development by regulating the expression of Hairy genes during intestinal remodeling. Furthermore, we show with organ culture experiments that prolonged exposure of tadpole intestine to TH plus GSI leads to hyperplasia of secretory cells and reduction of absorptive cells. Our findings here thus provide evidence for evolutionarily conserved role of Notch signaling in intestinal cell fate determination but more importantly reveal, for the first time, an important role of Notch pathway in the formation of adult intestinal stem cells during vertebrate development. Stem Cells 2017;35:1028-1039. © 2016 The Authors STEM CELLS published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.

Epithelial-mesenchymal transition transcription factors control pluripotent adult stem cell migration in vivo in planarians.

PubMed

Abnave, Prasad; Aboukhatwa, Ellen; Kosaka, Nobuyoshi; Thompson, James; Hill, Mark A; Aboobaker, A Aziz

2017-10-01

Migration of stem cells underpins the physiology of metazoan animals. For tissues to be maintained, stem cells and their progeny must migrate and differentiate in the correct positions. This need is even more acute after tissue damage by wounding or pathogenic infection. Inappropriate migration also underpins metastasis. Despite this, few mechanistic studies address stem cell migration during repair or homeostasis in adult tissues. Here, we present a shielded X-ray irradiation assay that allows us to follow stem cell migration in planarians. We demonstrate the use of this system to study the molecular control of stem cell migration and show that snail-1 , snail-2 and zeb-1 EMT transcription factor homologs are necessary for cell migration to wound sites and for the establishment of migratory cell morphology. We also observed that stem cells undergo homeostatic migration to anterior regions that lack local stem cells, in the absence of injury, maintaining tissue homeostasis. This requires the polarity determinant notum Our work establishes planarians as a suitable model for further in-depth study of the processes controlling stem cell migration in vivo . © 2017. Published by The Company of Biologists Ltd.

Melanocortin 1 receptor genotype: an important determinant of the damage response of melanocytes to ultraviolet radiation

PubMed Central

Kadekaro, Ana Luisa; Leachman, Sancy; Kavanagh, Renny J.; Swope, Viki; Cassidy, Pamela; Supp, Dorothy; Sartor, Maureen; Schwemberger, Sandy; Babcock, George; Wakamatsu, Kazumasa; Ito, Shosuke; Koshoffer, Amy; Boissy, Raymond E.; Manga, Prashiela; Sturm, Richard A.; Abdel-Malek, Zalfa A.

2010-01-01

The melanocortin 1 receptor gene is a main determinant of human pigmentation, and a melanoma susceptibility gene, because its variants that are strongly associated with red hair color increase melanoma risk. To test experimentally the association between melanocortin 1 receptor genotype and melanoma susceptibility, we compared the responses of primary human melanocyte cultures naturally expressing different melanocortin 1 receptor variants to α-melanocortin and ultraviolet radiation. We found that expression of 2 red hair variants abolished the response to α-melanocortin and its photoprotective effects, evidenced by lack of functional coupling of the receptor, and absence of reduction in ultraviolet radiation-induced hydrogen peroxide generation or enhancement of repair of DNA photoproducts, respectively. These variants had different heterozygous effects on receptor function. Microarray data confirmed the observed differences in responses of melanocytes with functional vs. nonfunctional receptor to α-melanocortin and ultraviolet radiation, and identified DNA repair and antioxidant genes that are modulated by α-melanocortin. Our findings highlight the molecular mechanisms by which the melanocortin 1 receptor genotype controls genomic stability of and the mutagenic effect of ultraviolet radiation on human melanocytes.—Kadekaro, A. L., Leachman, S., Kavanagh, R. J., Swope, V., Cassidy, P., Supp, D., Sartor, M., Schwemberger, S., Babcock, G., Wakamatsu, K., Ito, S., Koshoffer, A., Boissy, R. E., Manga, P., Sturm, R. A., Abdel-Malek, Z. A. Melanocortin 1 receptor genotype: an important determinant of the damage response of melanocytes to ultraviolet radiation. PMID:20519635

In vivo sensitivity of the embryonic and adult neural stem cell compartments to low-dose radiation.

PubMed

Barazzuol, Lara; Jeggo, Penny A

2016-08-01

The embryonic brain is radiation-sensitive, with cognitive deficits being observed after exposure to low radiation doses. Exposure of neonates to radiation can cause intracranial carcinogenesis. To gain insight into the basis underlying these outcomes, we examined the response of the embryonic, neonatal and adult brain to low-dose radiation, focusing on the neural stem cell compartments. This review summarizes our recent findings. At E13.5-14.5 the embryonic neocortex encompasses rapidly proliferating stem and progenitor cells. Exploiting mice with a hypomorphic mutation in DNA ligase IV (Lig4(Y288C) ), we found a high level of DNA double-strand breaks (DSBs) at E14.5, which we attribute to the rapid proliferation. We observed endogenous apoptosis in Lig4(Y288C) embryos and in WT embryos following exposure to low radiation doses. An examination of DSB levels and apoptosis in adult neural stem cell compartments, the subventricular zone (SVZ) and the subgranular zone (SGZ) revealed low DSB levels in Lig4(Y288C) mice, comparable with the levels in differentiated neuronal tissues. We conclude that the adult SVZ does not incur high levels of DNA breakage, but sensitively activates apoptosis; apoptosis was less sensitively activated in the SGZ, and differentiated neuronal tissues did not activate apoptosis. P5/P15 mice showed intermediate DSB levels, suggesting that DSBs generated in the embryo can be transmitted to neonates and undergo slow repair. Interestingly, this analysis revealed a stage of high endogenous apoptosis in the neonatal SVZ. Collectively, these studies reveal that the adult neural stem cell compartment, like the embryonic counterpart, can sensitively activate apoptosis. © The Author 2016. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

Dissecting the bulge in hair regeneration

PubMed Central

Ito, Mayumi; Myung, Peggy

2012-01-01

The adult hair follicle houses stem cells that govern the cyclical growth and differentiation of multiple cell types that collectively produce a pigmented hair. Recent studies have revealed that hair follicle stem cells are heterogeneous and dynamic throughout the hair cycle. Moreover, interactions between heterologous stem cells, including both epithelial and melanocyte stem cells, within the hair follicle are just now being explored. This review will describe how recent findings have expanded our understanding of the development, organization, and regeneration of hair follicle stem cells. At a basic level, this review is intended to help construct a reference point to integrate the surge of studies on the molecular mechanisms that regulate these cells. PMID:22293183

Hedgehog signaling activation induces stem cell proliferation and hormone release in the adult pituitary gland.

PubMed

Pyczek, Joanna; Buslei, Rolf; Schult, David; Hölsken, Annett; Buchfelder, Michael; Heß, Ina; Hahn, Heidi; Uhmann, Anja

2016-04-25

Hedgehog (HH) signaling is known to be essential during the embryonal development of the pituitary gland but the knowledge about its role in the adult pituitary and in associated tumors is sparse. In this report we investigated the effect of excess Hh signaling activation in murine pituitary explants and analyzed the HH signaling status of human adenopituitary lobes and a large cohort of pituitary adenomas. Our data show that excess Hh signaling led to increased proliferation of Sox2(+) and Sox9(+) adult pituitary stem cells and to elevated expression levels of adrenocorticotropic hormone (Acth), growth hormone (Gh) and prolactin (Prl) in the adult gland. Inhibition of the pathway by cyclopamine reversed these effects indicating that active Hh signaling positively regulates proliferative processes of adult pituitary stem cells and hormone production in the anterior pituitary. Since hormone producing cells of the adenohypophysis as well as ACTH-, GH- and PRL-immunopositive adenomas express SHH and its target GLI1, we furthermore propose that excess HH signaling is involved in the development/maintenance of hormone-producing pituitary adenomas. These findings advance the understanding of physiological hormone regulation and may open new treatment options for pituitary tumors.

Hedgehog signaling activation induces stem cell proliferation and hormone release in the adult pituitary gland

PubMed Central

Pyczek, Joanna; Buslei, Rolf; Schult, David; Hölsken, Annett; Buchfelder, Michael; Heß, Ina; Hahn, Heidi; Uhmann, Anja

2016-01-01

Hedgehog (HH) signaling is known to be essential during the embryonal development of the pituitary gland but the knowledge about its role in the adult pituitary and in associated tumors is sparse. In this report we investigated the effect of excess Hh signaling activation in murine pituitary explants and analyzed the HH signaling status of human adenopituitary lobes and a large cohort of pituitary adenomas. Our data show that excess Hh signaling led to increased proliferation of Sox2+ and Sox9+ adult pituitary stem cells and to elevated expression levels of adrenocorticotropic hormone (Acth), growth hormone (Gh) and prolactin (Prl) in the adult gland. Inhibition of the pathway by cyclopamine reversed these effects indicating that active Hh signaling positively regulates proliferative processes of adult pituitary stem cells and hormone production in the anterior pituitary. Since hormone producing cells of the adenohypophysis as well as ACTH-, GH- and PRL-immunopositive adenomas express SHH and its target GLI1, we furthermore propose that excess HH signaling is involved in the development/maintenance of hormone-producing pituitary adenomas. These findings advance the understanding of physiological hormone regulation and may open new treatment options for pituitary tumors. PMID:27109116

The effect of simultaneous exposure of HEMn-DP and HEMn-LP melanocytes to nicotine and UV-radiation on the cell viability and melanogenesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Delijewski, Marcin; Wrześniok, Dorota; Beberok, Ar

Nicotine is a main compound of tobacco plants and may affect more than a billion people all over the world that are permanently exposed to nicotine from cigarettes, various forms of smoking cessation therapies, electronic cigarettes or second-hand smoke. It is known that nicotine forms complexes with melanin what may lead to accumulation of this alkaloid in tissues of living organisms containing the pigment. This may affect the viability of cells and process of melanin biosynthesis that takes place in melanocytes. Although UV radiation is known to be a particular inductor of melanin biosynthesis, its simultaneous effect with nicotine onmore » this process as well as the viability of human cells containing melanin have not been assessed so far. The aim of this study was to examine the simultaneous impact of nicotine and UV radiation on viability and melanogenesis in cultured normal human melanocytes dark (HEMn-DP) and light (HEMn-LP) pigmented. Nicotine together with UV radiation induced concentration-dependent loss in melanocytes viability. The higher cell loss was observed in dark pigmented melanocytes in comparison to light pigmented cells. Simultaneous exposure of cells to nicotine and UV radiation also caused changes in melanization process in both tested cell lines. The data suggest that simultaneous exposure of melanocytes to nicotine and UV radiation up-regulates melanogenesis and affects cell viability. Observed processes are more pronounced in dark pigmented cells. - Highlights: • Nicotine and UVA induced concentration-dependent loss in melanocytes viability. • Nicotine and UVA modulated melanization process in melanocytes. • Changes in viability and melanization were more pronounced in dark pigmented cells.« less

Ovarian stem cells are always accompanied by very small embryonic-like stem cells in adult mammalian ovary.

PubMed

Bhartiya, Deepa

2015-11-05

Existing dogma that a female is born with fixed number of eggs was challenged by the detection of stem cells in adult mammalian ovary. Data has accumulated in support of ovarian stem cells (OSCs) proliferation, maintenance in culture, formation of germ cell nests and differentiation into oocytes and primordial follicle assembly using different strategies. Flow cytometry analysis identified >8 μm OSCs which are DDX1 positive and are considered equivalent to spermatogonial stem cells (SSCs) in testis. Analysis of both ovarian and testicular smears obtained after enzymatic digestion has led to the identification of an additional stem cell population termed very small embryonic-like stem cells (VSELs). VSELs and OSCs/SSCs differ from each other in their size and OCT-4 expression. VSELs express pluripotent markers including nuclear OCT-4 whereas OSCs/SSCs express cytoplasmic OCT-4 suggesting a differentiated state. VSELs can be studied by flow cytometry as small sized cells which are LIN-/CD45-/Sca-1+. We have reported 0.02 ± 0.008, 0.03 ± 0.017 and 0.08 ± 0.03 % of total cells as VSELs in normal, chemoablated and after FSH treatment to chemoablated mouse ovary. VSELs have remained poorly studied till now because of their very small size and rare occurrence. Spinning cells obtained after enzymatic digestion of ovarian tissue at a speed of 1000G (rather than 1200 rpm) throughout processing allows reliable detection of the VSELs by flow cytometry. VSELs exist in aged, chemoablated and non-functional ovary and providing a healthy niche to support their function offers an interesting strategy to manage infertility.

Label-Free Imaging of Female Genital Tract Melanocytic Lesions With Pump-Probe Microscopy: A Promising Diagnostic Tool.

PubMed

Robles, Francisco E; Deb, Sanghamitra; Fischer, Martin C; Warren, Warren S; Selim, Maria Angelica

2017-04-01

Melanomas of the female genital tract present a unique clinical challenge. Not only are these lesions in an anatomically sensitive area, but also they tend to be multifocal and have high recurrence rates. Furthermore, several benign melanocytic proliferations resemble early-stage melanoma clinically and/or histopathologically. Thus, there is a significant need for additional tools that can help correctly diagnose and stage these lesions. Here, we quantitatively and nondestructively analyze the chemical composition of melanin in excised pigmented lesions of the female genital tract using pump-probe microscopy, a high-resolution optical imaging technique that is sensitive to many biochemical properties of melanin. Thirty-one thin (~5 μm) tissue sections previously excised from female genital tract melanocytic lesions were imaged with pump-probe microscopy and analyzed. We find significant quantitative differences in melanin type and structure between melanoma and nonmalignant melanocytic proliferations. Our analysis also suggests a link between the molecular signatures of melanins and lesion-specific genetic mutations. Finally, significant differences are found between metastatic and nonmetastatic melanomas. The limitations of this work include the fact that molecular information is restricted to melanin pigment and the sample size is relatively small. Pump-probe microscopy provides unique information regarding the biochemical composition of genital tract melanocytic lesions, which can be used to improve the diagnosis and staging of vulvar melanomas.

FSH-FSHR3-stem cells in ovary surface epithelium: basis for adult ovarian biology, failure, aging, and cancer.

PubMed

Bhartiya, Deepa; Singh, Jarnail

2015-01-01

Despite extensive research, genetic basis of premature ovarian failure (POF) and ovarian cancer still remains elusive. It is indeed paradoxical that scientists searched for mutations in FSH receptor (FSHR) expressed on granulosa cells, whereas more than 90% of cancers arise in ovary surface epithelium (OSE). Two distinct populations of stem cells including very small embryonic-like stem cells (VSELs) and ovarian stem cells (OSCs) exist in OSE, are responsible for neo-oogenesis and primordial follicle assembly in adult life, and are modulated by FSH via its alternatively spliced receptor variant FSHR3 (growth factor type 1 receptor acting via calcium signaling and the ERK/MAPK pathway). Any defect in FSH-FSHR3-stem cell interaction in OSE may affect folliculogenesis and thus result in POF. Ovarian aging is associated with a compromised microenvironment that does not support stem cell differentiation into oocytes and further folliculogenesis. FSH exerts a mitogenic effect on OSE and elevated FSH levels associated with advanced age may provide a continuous trigger for stem cells to proliferate resulting in cancer, thus supporting gonadotropin theory for ovarian cancer. Present review is an attempt to put adult ovarian biology, POF, aging, and cancer in the perspective of FSH-FSHR3-stem cell network that functions in OSE. This hypothesis is further supported by the recent understanding that: i) cancer is a stem cell disease and OSE is the niche for ovarian cancer stem cells; ii) ovarian OCT4-positive stem cells are regulated by FSH; and iii) OCT4 along with LIN28 and BMP4 are highly expressed in ovarian cancers. © 2015 Society for Reproduction and Fertility.

The RNA-binding protein Musashi-1 is produced in the developing and adult mouse eye.

PubMed

Raji, B; Dansault, A; Leemput, J; de la Houssaye, G; Vieira, V; Kobetz, A; Arbogast, L; Masson, C; Menasche, M; Abitbol, M

2007-08-10

Musashi-1 (Msi1) is an RNA-binding protein produced in various types of stem cells including neural stem/progenitor cells and astroglial progenitor cells in the vertebrate central nervous system. Other RNA-binding proteins such as Pumilio-1, Pumilio-2, Staufen-1, and Staufen-2 have been characterized as potential markers of several types of stem or progenitor cells. We investigated the involvement of Msi1 in mouse eye development and adult mouse eye functions by analyzing the profile of Msi1 production in all ocular structures during development and adulthood. We studied Msi1 production by in situ hybridization and immunohistochemistry of ocular tissue sections and by semi-quantitative RT-PCR and western blot analysis from the embryonic stage of 12.5 days post coitum (E12.5 dpc) when the first retinal ganglion cells (RGCs) begin to appear to the adult stage when all retinal cell types are present. Msi1 mRNA was present at all studied stages of eye development. Msi1 protein was detected in the primitive neuroblastic layer (NbL), the ganglion cell layer (GCL), and in all major differentiated neurons of postnatal developing and adult retinae. During postnatal developing stages, faint diffuse Msi1 protein staining is converted to a more specific distribution once mouse retina is fully differentiated. The most striking result of our study concerns the large amounts of Msi1 protein and mRNA in several unexpected sites of adult mouse eyes including the corneal epithelium and endothelium, stromal keratocytes, progenitor cells of the limbus, equatorial lens stem cells, differentiated lens epithelial cells, and differentiating lens fibers. Msi1 was also found in the pigmented and nonpigmented cells of the ciliary processes, the melanocytes of the ciliary body, the retinal pigment epithelium, differentiated retinal neurons, and most probably in the retinal glial cells such as Müller glial cells, astrocytes, and the oligodendocytes surrounding the axons of the optic nerve

Sirt1 Protects Stressed Adult Hematopoietic Stem Cells | Center for Cancer Research

Cancer.gov

The immune system relies on a stable pool of hematopoietic stem and progenitor cells (HSPCs) to respond properly to injury or stress. Maintaining genomic integrity and appropriate gene expression is essential for HSPC homeostasis, and dysregulation can result in myeloproliferative disorders or loss of immune function. Sirt1 is a histone deacetylase that can protect embryonic stem (ES) cells from accumulating DNA damage and has been linked to hematopoietic differentiation of ES cells. Satyendra Singh, Ph.D., a postdoctoral fellow working with Philipp Oberdoerffer, Ph.D., in CCR’s Laboratory of Receptor Biology and Gene Expression, and their colleagues set out to determine whether Sirt1 could play a similar protective role in adult HSPCs.

What is a stem cell?

PubMed

Slack, Jonathan M W

2018-05-15

The historical roots of the stem cell concept are traced with respect to its usage in embryology and in hematology. The modern consensus definition of stem cells, comprising both pluripotent stem cells in culture and tissue-specific stem cells in vivo, is explained and explored. Methods for identifying stem cells are discussed with respect to cell surface markers, telomerase, label retention and transplantability, and properties of the stem cell niche are explored. The CreER method for identifying stem cells in vivo is explained, as is evidence in favor of a stochastic rather than an obligate asymmetric form of cell division. In conclusion, it is found that stem cells do not possess any unique and specific molecular markers; and stem cell behavior depends on the environment of the cell as well as the stem cell's intrinsic qualities. Furthermore, the stochastic mode of division implies that stem cell behavior is a property of a cell population not of an individual cell. In this sense, stem cells do not exist in isolation but only as a part of multicellular system. This article is categorized under: Adult Stem Cells, Tissue Renewal, and Regeneration > Tissue Stem Cells and Niches Adult Stem Cells, Tissue Renewal, and Regeneration > Methods and Principles Adult Stem Cells, Tissue Renewal, and Regeneration > Environmental Control of Stem Cells. © 2018 Wiley Periodicals, Inc.

NEAR-INFRARED AUTOFLUORESCENCE IN BILATERAL DIFFUSE UVEAL MELANOCYTIC PROLIFERATION ASSOCIATED WITH ESOPHAGEAL CARCINOMA AND CHOROIDAL METASTASIS.

PubMed

Golshahi, Azadeh; Bornfeld, Norbert; Weinitz, Silke; Kellner, Ulrich

2016-01-01

To investigate the advantage of near-infrared autofluorescence (787 nm) for the detection of melanocytic lesions in a patient with bilateral diffuse uveal melanocytic proliferation in association with esophageal carcinoma complicated by most likely unilateral choroidal metastasis. In this retrospective case report, a 55-year-old woman referred for the evaluation of sudden visual loss underwent normal ophthalmological evaluation and, in addition, was examined with near-infrared reflectance, near-infrared autofluorescence, fundus autofluorescence (Heidelberg Retina Angiograph II [HRA2; Heidelberg Engineering]), spectral domain optical coherence tomography (Spectralis OCT; Heidelberg Engineering), and multifocal electroretinography (RetiScan; Roland Consult). The patient had been diagnosed with esophageal carcinoma 3 months before the onset of visual symptoms. The visual acuity was 20/40 in the right eye and 20/20 in the left eye. Bilateral patchy melanocytic proliferation was detected on ophthalmoscopy. The extent of lesions was best detected with near-infrared reflectance and near-infrared autofluorescence, whereas fundus autofluorescence and spectral domain optical coherence tomography did not reveal alterations of the outer retina or retinal pigment epithelium in this early stage of bilateral diffuse uveal melanocytic proliferation. The right eye showed in addition to the findings on the left eye choroidal folds in the fovea and an elevated lesion inferotemporal of the fovea suspicious of a choroidal metastasis. In the B-scan ultrasonography, a homogenous lesion was seen. Spectral domain optical coherence tomography demonstrated a mild accumulation of subretinal fluid adjacent to and over the choroidal metastasis. Transretinal biopsy of this elevated lesion revealed a low differentiated carcinoma of squamous epithelium, compatible with choroidal metastasis of the esophageal carcinoma. The choroidal metastasis increased within 3 months after the first visit. The

Discovering novel phenotypes with automatically inferred dynamic models: a partial melanocyte conversion in Xenopus

NASA Astrophysics Data System (ADS)

Lobo, Daniel; Lobikin, Maria; Levin, Michael

2017-01-01

Progress in regenerative medicine requires reverse-engineering cellular control networks to infer perturbations with desired systems-level outcomes. Such dynamic models allow phenotypic predictions for novel perturbations to be rapidly assessed in silico. Here, we analyzed a Xenopus model of conversion of melanocytes to a metastatic-like phenotype only previously observed in an all-or-none manner. Prior in vivo genetic and pharmacological experiments showed that individual animals either fully convert or remain normal, at some characteristic frequency after a given perturbation. We developed a Machine Learning method which inferred a model explaining this complex, stochastic all-or-none dataset. We then used this model to ask how a new phenotype could be generated: animals in which only some of the melanocytes converted. Systematically performing in silico perturbations, the model predicted that a combination of altanserin (5HTR2 inhibitor), reserpine (VMAT inhibitor), and VP16-XlCreb1 (constitutively active CREB) would break the all-or-none concordance. Remarkably, applying the predicted combination of three reagents in vivo revealed precisely the expected novel outcome, resulting in partial conversion of melanocytes within individuals. This work demonstrates the capability of automated analysis of dynamic models of signaling networks to discover novel phenotypes and predictively identify specific manipulations that can reach them.

Tumor suppressors Sav/Scrib and oncogene Ras regulate stem cell transformation in adult Drosophila Malpighian Tubules

PubMed Central

Zeng, Xiankun; Singh, Shree Ram; Hou, David; Hou, Steven X.

2012-01-01

An increasing body of evidence suggests that tumors might originate from a few transformed cells that share many properties with normal stem cells. However, it remains unclear how normal stem cells are transformed into cancer stem cells. Here, we demonstrated that mutations causing the loss of tumor suppressor Sav or Scrib or activation of the oncogene Ras transform normal stem cells into cancer stem cells through a multistep process in the adult Drosophila Malpighian Tubules (MTs). In wild-type MTs, each stem cell generates one self-renewing and one differentiating daughter cell. However, in flies with loss-of-function sav or scrib or gain-of-function Ras mutations, both daughter cells grew and behaved like stem cells, leading to the formation of tumors in MTs. Ras functioned downstream of Sav and Scrib in regulating the stem cell transformation. The Ras-transformed stem cells exhibited many of the hallmarks of cancer, such as increased proliferation, reduced cell death, and failure to differentiate. We further demonstrated that several signal transduction pathways (including MEK/MAPK, RhoA, PKA, and TOR) mediate Rasṕ function in the stem cell transformation. Therefore, we have identified a molecular mechanism that regulates stem cell transformation, and this finding may lead to strategies for preventing tumor formation in certain organs. PMID:20432470

Thyroid Hormone‐Induced Activation of Notch Signaling is Required for Adult Intestinal Stem Cell Development During Xenopus Laevis Metamorphosis

PubMed Central

Fujimoto, Kenta; Kajita, Mitsuko; Fu, Liezhen; Shi, Yun‐Bo; Ishizuya‐Oka, Atsuko

2016-01-01

Abstract In Xenopus laevis intestine during metamorphosis, the larval epithelial cells are removed by apoptosis, and the adult epithelial stem (AE) cells appear concomitantly. They proliferate and differentiate to form the adult epithelium (Ep). Thyroid hormone (TH) is well established to trigger this remodeling by regulating the expression of various genes including Notch receptor. To study the role of Notch signaling, we have analyzed the expression of its components, including the ligands (DLL and Jag), receptor (Notch), and targets (Hairy), in the metamorphosing intestine by real‐time reverse transcription‐polymerase chain reaction and in situ hybridization or immunohistochemistry. We show that they are up‐regulated during both natural and TH‐induced metamorphosis in a tissue‐specific manner. Particularly, Hairy1 is specifically expressed in the AE cells. Moreover, up‐regulation of Hairy1 and Hairy2b by TH was prevented by treating tadpoles with a γ‐secretase inhibitor (GSI), which inhibits Notch signaling. More importantly, TH‐induced up‐regulation of LGR5, an adult intestinal stem cell marker, was suppressed by GSI treatment. Our results suggest that Notch signaling plays a role in stem cell development by regulating the expression of Hairy genes during intestinal remodeling. Furthermore, we show with organ culture experiments that prolonged exposure of tadpole intestine to TH plus GSI leads to hyperplasia of secretory cells and reduction of absorptive cells. Our findings here thus provide evidence for evolutionarily conserved role of Notch signaling in intestinal cell fate determination but more importantly reveal, for the first time, an important role of Notch pathway in the formation of adult intestinal stem cells during vertebrate development. Stem Cells 2017;35:1028–1039 PMID:27870267

Rab11b mediates melanin transfer between donor melanocytes and acceptor keratinocytes via coupled exo/endocytosis.

PubMed

Tarafder, Abul K; Bolasco, Giulia; Correia, Maria S; Pereira, Francisco J C; Iannone, Lucio; Hume, Alistair N; Kirkpatrick, Niall; Picardo, Mauro; Torrisi, Maria R; Rodrigues, Inês P; Ramalho, José S; Futter, Clare E; Barral, Duarte C; Seabra, Miguel C

2014-04-01

The transfer of melanin from melanocytes to keratinocytes is a crucial process underlying maintenance of skin pigmentation and photoprotection against UV damage. Here, we present evidence supporting coupled exocytosis of the melanin core, or melanocore, by melanocytes and subsequent endocytosis by keratinocytes as a predominant mechanism of melanin transfer. Electron microscopy analysis of human skin samples revealed three lines of evidence supporting this: (1) the presence of melanocores in the extracellular space; (2) within keratinocytes, melanin was surrounded by a single membrane; and (3) this membrane lacked the melanosomal membrane protein tyrosinase-related protein 1 (TYRP1). Moreover, co-culture of melanocytes and keratinocytes suggests that melanin exocytosis is specifically induced by keratinocytes. Furthermore, depletion of Rab11b, but not Rab27a, caused a marked decrease in both keratinocyte-stimulated melanin exocytosis and transfer to keratinocytes. Thus, we propose that the predominant mechanism of melanin transfer is keratinocyte-induced exocytosis, mediated by Rab11b through remodeling of the melanosome membrane, followed by subsequent endocytosis by keratinocytes.

Robust G2 pausing of adult stem cells in Hydra.

PubMed

Buzgariu, Wanda; Crescenzi, Marco; Galliot, Brigitte

2014-01-01

Hydra is a freshwater hydrozoan polyp that constantly renews its two tissue layers thanks to three distinct stem cell populations that cannot replace each other, epithelial ectodermal, epithelial endodermal, and multipotent interstitial. These adult stem cells, located in the central body column, exhibit different cycling paces, slow for the epithelial, fast for the interstitial. To monitor the changes in cell cycling in Hydra, we established a fast and efficient flow cytometry procedure, which we validated by confirming previous findings, as the Nocodazole-induced reversible arrest of cell cycling in G2/M, and the mitogenic signal provided by feeding. Then to dissect the cycling and differentiation behaviors of the interstitial stem cells, we used the AEP_cnnos1 and AEP_Icy1 transgenic lines that constitutively express GFP in this lineage. For the epithelial lineages we used the sf-1 strain that rapidly eliminates the fast cycling cells upon heat-shock and progressively becomes epithelial. This study evidences similar cycling patterns for the interstitial and epithelial stem cells, which all alternate between the G2 and S-phases traversing a minimal G1-phase. We also found interstitial progenitors with a shorter G2 that pause in G1/G0. At the animal extremities, most cells no longer cycle, the epithelial cells terminally differentiate in G2 and the interstitial progenitors in G1/G0. At the apical pole ~80% cells are post-mitotic differentiated cells, reflecting the higher density of neurons and nematocytes in this region. We discuss how the robust G2 pausing of stem cells, maintained over weeks of starvation, may contribute to regeneration. Copyright © 2014 International Society of Differentiation. Published by Elsevier B.V. All rights reserved.

Stem cells distribution, cellular proliferation and migration in the adult Austrolebias charrua brain.

PubMed

Torres-Pérez, Maximiliano; Rosillo, Juan Carlos; Berrosteguieta, Ines; Olivera-Bravo, Silvia; Casanova, Gabriela; García-Verdugo, José Manuel; Fernández, Anabel Sonia

2017-10-15

Our previous studies demonstrated that Austrolebias charrua annual fish is an excellent model to study adult brain cell proliferation and neurogenesis due to the presence of active and fast neurogenesis in several regions during its short lifespan. Our main goal was to identify and localize the cells that compose the neurogenic areas throughout the Austrolebias brain. To do this, we used two thymidine halogenated analogs to detect cell proliferation at different survival times: 5-chloro-2'-deoxyuridine (CldU) at 1day and 5-iodo-2'-deoxyuridine (IdU) at 30days. Three types of proliferating cells were identified: I - transient amplifying or fast cycling cells that uptake CldU; II - stem cells or slow cycling cells, that were labeled with both CldU and IdU and did not migrate; and III - migrant cells that uptake IdU. Mapping and 3D-reconstruction of labeled nuclei showed that type I and type II cells were preferentially found close to ventricle walls. Type III cells appeared widespread and migrating in tangential and radial routes. Use of proliferation markers together with Vimentin or Nestin evidenced that type II cells are the putative stem cells that are located at the ventricular lumen. Double label cells with IdU+ and NeuN or HuC/D allowed us identify migrant neurons. Quantitation of labeled nuclei indicates that the proportion of putative stem cells is around 10% in all regions of the brain. This percentage of stem cells suggests the existence of a constant brain cell population in Austrolebias charrua that seems functional to the maintainance of adult neurogenesis. Copyright © 2017 Elsevier B.V. All rights reserved.

Isolation and characterization of porcine adipose tissue-derived adult stem cells.

PubMed

Williams, Kellie J; Picou, Alicia A; Kish, Sharon L; Giraldo, Angelica M; Godke, Robert A; Bondioli, Kenneth R

2008-01-01

Stem cell characteristics such as self-renewal, differentiation and expression of CD34 and CD44 stem cell markers have not been identified in porcine adipose tissue-derived adult stem (ADAS) cells. The objective of this study was to develop a protocol for the isolation and culture of porcine adipose tissue-derived cells and to determine stem cell-like characteristics. Primary cultures were established and cell cultures were maintained. Cloning capacity was determined using a ring cloning procedure. Primary cultures and clones were differentiated and stained for multiple differentiated phenotypes. CD34 and CD44 messenger ribonucleic acid (mRNA) was isolated and reverse transcriptase polymerase chain reaction was used to compare expression profiles. An average of 2,700,000 nucleated cells/ml was isolated; 26% were adherent, and cells completed a cell cycle approximately every 3.3 days. Ring cloning identified 19 colonies. Primary cultures and clones were determined to differentiate along osteogenic, adipogenic and chondrogenic tissue lineages. The mRNA expression profiles showed CD34 expression was higher for undifferentiated ADAS cells versus differentiated cell types and the CD34 expression level was lower than that of CD44 among differentiated cells. Improved culture conditions and defined cellular characteristics of these porcine ADAS cells have been identified. Porcine ADAS can self-renew, can differentiate into multiple tissue lineages and they express CD34. Copyright 2008 S. Karger AG, Basel.

Reserve stem cells: Reprogramming of differentiated cells fuels repair, metaplasia, and neoplasia in the adult gastrointestinal tract

PubMed Central

Mills, Jason C.; Sansom, Owen J.

2016-01-01

It has long been known that differentiated cells can switch fates, especially in vitro, but only recently has there been a critical mass of publications describing the mechanisms adult, post-mitotic cells use in vivo to reverse their differentiation state. We propose that this sort of cellular reprogramming is a fundamental cellular process akin to apoptosis or mitosis. Because reprogramming can invoke regenerative cells from mature cells, it is critical to the longterm maintenance of tissues like the pancreas, which encounter large insults during adulthood but lack constitutively active adult stem cells to repair the damage. However, even in tissues with adult stem cells, like stomach and intestine, reprogramming may allow mature cells to serve as reserve (“quiescent”) stem cells when normal stem cells are compromised. We propose that the potential downside to reprogramming is that it increases risk for cancers that occur late in adulthood. Mature, long-lived cells may have years of exposure to mutagens. Mutations that affect the physiological function of differentiated, post-mitotic cells may lead to apoptosis, but mutations in genes that govern proliferation might not be selected against. Hence, reprogramming with reentry into the cell cycle might unmask those mutations, causing an irreversible progenitor-like, proliferative state. We review recent evidence showing that reprogramming fuels irreversible metaplastic and precancerous proliferations in stomach and pancreas. Finally, we illustrate how we think reprogrammed differentiated cells are likely candidates as cells of origin for cancers of the intestine. PMID:26175494

Mouse embryonic stem cell-derived cells reveal niches that support neuronal differentiation in the adult rat brain.

PubMed

Maya-Espinosa, Guadalupe; Collazo-Navarrete, Omar; Millán-Aldaco, Diana; Palomero-Rivero, Marcela; Guerrero-Flores, Gilda; Drucker-Colín, René; Covarrubias, Luis; Guerra-Crespo, Magdalena

2015-02-01

A neurogenic niche can be identified by the proliferation and differentiation of its naturally residing neural stem cells. However, it remains unclear whether "silent" neurogenic niches or regions suitable for neural differentiation, other than the areas of active neurogenesis, exist in the adult brain. Embryoid body (EB) cells derived from embryonic stem cells (ESCs) are endowed with a high potential to respond to specification and neuralization signals of the embryo. Hence, to identify microenvironments in the postnatal and adult rat brain with the capacity to support neuronal differentiation, we transplanted dissociated EB cells to conventional neurogenic and non-neurogenic regions. Our results show a neuronal differentiation pattern of EB cells that was dependent on the host region. Efficient neuronal differentiation of EB cells occurred within an adjacent region to the rostral migratory stream. EB cell differentiation was initially patchy and progressed toward an even distribution along the graft by 15-21 days post-transplantation, giving rise mostly to GABAergic neurons. EB cells in the striatum displayed a lower level of neuronal differentiation and derived into a significant number of astrocytes. Remarkably, when EB cells were transplanted to the striatum of adult rats after a local ischemic stroke, increased number of neuroblasts and neurons were observed. Unexpectedly, we determined that the adult substantia nigra pars compacta, considered a non-neurogenic area, harbors a robust neurogenic environment. Therefore, neurally uncommitted cells derived from ESCs can detect regions that support neuronal differentiation within the adult brain, a fundamental step for the development of stem cell-based replacement therapies. © 2014 AlphaMed Press.

The novel steroidal alkaloids dendrogenin A and B promote proliferation of adult neural stem cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khalifa, Shaden A.M., E-mail: shaden.khalifa@ki.se; Medina, Philippe de; INSERM UMR 1037, Team “Sterol Metabolism and Therapeutic Innovations in Oncology”, Cancer Research Center of Toulouse, F-31052 Toulouse

2014-04-11

Highlights: • Dendrogenin A and B are new aminoalkyl oxysterols. • Dendrogenins stimulated neural stem cells proliferation. • Dendrogenins induce neuronal outgrowth from neurospheres. • Dendrogenins provide new therapeutic options for neurodegenerative disorders. - Abstract: Dendrogenin A (DDA) and dendrogenin B (DDB) are new aminoalkyl oxysterols which display re-differentiation of tumor cells of neuronal origin at nanomolar concentrations. We analyzed the influence of dendrogenins on adult mice neural stem cell proliferation, sphere formation and differentiation. DDA and DDB were found to have potent proliferative effects in neural stem cells. Additionally, they induce neuronal outgrowth from neurospheres during in vitro cultivation.more » Taken together, our results demonstrate a novel role for dendrogenins A and B in neural stem cell proliferation and differentiation which further increases their likely importance to compensate for neuronal cell loss in the brain.« less

Planarian MBD2/3 is required for adult stem cell pluripotency independently of DNA methylation☆

PubMed Central

Jaber-Hijazi, Farah; Lo, Priscilla J.K.P.; Mihaylova, Yuliana; Foster, Jeremy M.; Benner, Jack S.; Tejada Romero, Belen; Chen, Chen; Malla, Sunir; Solana, Jordi; Ruzov, Alexey; Aziz Aboobaker, A.

2013-01-01

Planarian adult stem cells (pASCs) or neoblasts represent an ideal system to study the evolution of stem cells and pluripotency as they underpin an unrivaled capacity for regeneration. We wish to understand the control of differentiation and pluripotency in pASCs and to understand how conserved, convergent or divergent these mechanisms are across the Bilateria. Here we show the planarian methyl-CpG Binding Domain 2/3 (mbd2/3) gene is required for pASC differentiation during regeneration and tissue homeostasis. The genome does not have detectable levels of 5-methylcytosine (5mC) and we find no role for a potential DNA methylase. We conclude that MBD proteins may have had an ancient role in broadly controlling animal stem cell pluripotency, but that DNA methylation is not involved in planarian stem cell differentiation. PMID:24063805

Germline stem cells and neo-oogenesis in the adult human ovary.

PubMed

Liu, Yifei; Wu, Chao; Lyu, Qifeng; Yang, Dongzi; Albertini, David F; Keefe, David L; Liu, Lin

2007-06-01

It remains unclear whether neo-oogenesis occurs in postnatal ovaries of mammals, based on studies in mice. We thought to test whether adult human ovaries contain germline stem cells (GSCs) and undergo neo-oogenesis. Rather than using genetic manipulation which is unethical in humans, we took the approach of analyzing the expression of meiotic marker genes and genes for germ cell proliferation, which are required for neo-oogenesis, in adult human ovaries covering an age range from 28 to 53 years old, compared to testis and fetal ovaries served as positive controls. We show that active meiosis, neo-oogenesis and GSCs are unlikely to exist in normal, adult, human ovaries. No early meiotic-specific or oogenesis-associated mRNAs for SPO11, PRDM9, SCP1, TERT and NOBOX were detectable in adult human ovaries using RT-PCR, compared to fetal ovary and adult testis controls. These findings are further corroborated by the absence of early meiocytes and proliferating germ cells in adult human ovarian cortex probed with markers for meiosis (SCP3), oogonium (OCT3/4, c-KIT), and cell cycle progression (Ki-67, PCNA), in contrast to fetal ovary controls. If postnatal oogenesis is confirmed in mice, then this species would represent an exception to the rule that neo-oogenesis does not occur in adults.

Adult mesenchymal stem cells and women's health.

PubMed

Caplan, Arnold I

2015-02-01

Adult mesenchymal stem cells (MSCs) were previously described as multipotent cells that could differentiate into bone, cartilage, muscle, and other mesenchymal tissues. New information suggests that MSCs can be found in every tissue of the body because they function as perivascular cells--pericytes--found outside all blood vessels. When these vessels break or are inflamed, pericytes are detached and form MSCs, which are activated by their local microenvironment of injury. Such MSCs function to secrete powerful immune-modulatory and regenerative agents; more than 450 clinical trials are now ongoing, covering a huge spectrum of clinical conditions. How such activated MSCs affect menstrual cycle, menopause, or osteotrophic cancers has only recently been studied. This article outlines these issues and challenges the scientific and medical community to use this newfound knowledge to uncover new clinical logics and medial solutions for women.

The Perceived Threat in Adults with Leukemia Undergoing Hematopoietic Stem Cell Transplantation

PubMed Central

Farsi, Zahra; Dehghan Nayeri, Nahid; Negarandeh, Reza

2013-01-01

Background: Leukemia and hematopoietic stem cell transplantation (HSCT) create physical, psychological, social, and spiritual distresses in patients. Understanding this threatening situation in adults with leukemia undergoing HSCT will assist health care professionals in providing holistic care to the patients. Objectives: The aim of the present study was exploring the perceived threat in adults with leukemia undergoing HSCT. Patients and Methods: This article is part of a longitudinal qualitative study which used the grounded theory approach and was conducted in 2009-2011. Ten adults with acute leukemia scheduled for HSCT were recruited from the Hematology–Oncology Research Center and Stem Cell Transplantation, Shariati Hospital in Tehran, Iran. A series of pre-transplant and post-transplant in-depth interviews were held in the hospital’s HSCT wards. Totally, 18 interviews were conducted. Three written narratives were also obtained from the participants. The Corbin and Strauss approach was used to analyze the data. Results: Perceived threat was one of the main categories that emerged from the data. This category included four subcategories, "inattention to the signs and symptoms", "doubt and anxiety", "perception of danger and time limitation" and "change of life conditions", which occurred in linear progression over time. Conclusion: Suffering from leukemia and experiencing HSCT are events that are uniquely perceived by patients. This threatening situation can significantly effect perception of patients and cause temporary or permanent alterations in patients' lives. Health care professionals can help these patients by deeper understanding of their experiences and effective interventions. PMID:25414863

MicroRNA expression in melanocytic nevi: the usefulness of formalin-fixed, paraffin-embedded material for miRNA microarray profiling.

PubMed

Glud, Martin; Klausen, Mikkel; Gniadecki, Robert; Rossing, Maria; Hastrup, Nina; Nielsen, Finn C; Drzewiecki, Krzysztof T

2009-05-01

MicroRNAs (miRNAs) are small, noncoding RNA molecules that regulate cellular differentiation, proliferation, and apoptosis. MiRNAs are expressed in a developmentally regulated and tissue-specific manner. Aberrant expression may contribute to pathological processes such as cancer, and miRNA may therefore serve as biomarkers that may be useful in a clinical environment for diagnosis of various diseases. Most miRNA profiling studies have used fresh tissue samples. However, in some types of cancer, including malignant melanoma, fresh material is difficult to obtain from primary tumors, and most surgical specimens are formalin fixed and paraffin embedded (FFPE). To explore whether FFPE material would be suitable for miRNA profiling in melanocytic lesions, we compared miRNA expression patterns in FFPE versus fresh frozen samples, obtained from 15 human melanocytic nevi. Out of microarray data, we identified 84 miRNAs that were expressed in both types of samples and represented an miRNA profile of melanocytic nevi. Our results showed a high correlation in miRNA expression (Spearman r-value of 0.80) between paired FFPE and fresh frozen material. The data were further validated by quantitative RT-PCR. In conclusion, FFPE specimens of melanocytic lesions are suitable as a source for miRNA microarray profiling.

Exosomes released by keratinocytes modulate melanocyte pigmentation

PubMed Central

Cicero, Alessandra Lo; Delevoye, Cédric; Gilles-Marsens, Floriane; Loew, Damarys; Dingli, Florent; Guéré, Christelle; André, Nathalie; Vié, Katell; van Niel, Guillaume; Raposo, Graça

2015-01-01

Cells secrete extracellular vesicles (EVs), exosomes and microvesicles, which transfer proteins, lipids and RNAs to regulate recipient cell functions. Skin pigmentation relies on a tight dialogue between keratinocytes and melanocytes in the epidermis. Here we report that exosomes secreted by keratinocytes enhance melanin synthesis by increasing both the expression and activity of melanosomal proteins. Furthermore, we show that the function of keratinocyte-derived exosomes is phototype-dependent and is modulated by ultraviolet B. In sum, this study uncovers an important physiological function for exosomes in human pigmentation and opens new avenues in our understanding of how pigmentation is regulated by intercellular communication in both healthy and diseased states. PMID:26103923

The hair follicle bulge: a niche for adult stem cells.

PubMed

Pasolli, Hilda Amalia

2011-08-01

Adult stem cells (SCs) are essential for tissue homeostasis and wound repair. They have the ability to both self-renew and differentiate into multiple cell types. They often reside in specialized microenvironments or niches that preserve their proliferative and tissue regenerative capacity. The murine hair follicle (HF) has a specialized and permanent compartment--the bulge, which safely lodges SCs and provides the necessary molecular cues to regulate their function. The HF undergoes cyclic periods of destruction, regeneration, and rest, making it an excellent system to study SC biology.

Stem cells--clinical application and perspectives.

PubMed

Brehm, Michael; Zeus, Tobias; Strauer, Bodo Eckehard

2002-11-01

Augmentation of myocardial performance in experimental models of therapeutic infarction and heart failure has been achieved by transplantation of exogenous cells into damaged myocardium. The quest for suitable donor cells has prompted research into the use of both embryonic stem cells and adult somatic stem cells. Recently, there has been a growing body of evidence that multipotent somatic stem cells in adult bone marrow exhibit tremendous functional plasticity and can reprogram in a new environmental tissue niche to give rise to cell lineages specific for new organ site. This phenomenon has made huge impact on myocardial biology, while multipotent adult bone marrow hematopoeitic stem cells and mesechymal stem cells can repopulate infarcted rodent myocardium and differentiate into both cardiomyocytes and new blood vessels. These data, coupled with the identification of a putative primitive cardiac stem cell population in the adult human heart, may open the way for novel therapeutic modalities for enhancing myocardial performance and treating heart failure.

Complete regression of a melanocytic nevus under intense pulsed light therapy for axillary hair removal in a cosmetic center.

PubMed

Martín, José M; Monteagudo, Carlos; Bella, Rebeca; Reig, Irela; Jordá, Esperanza

2012-01-01

Intense pulsed light (IPL) therapy using noncoherent broad-spectrum light has been reported to be effective for hair removal, and also for treating superficial pigmented lesions like ephelides and solar lentigines. We report complete regression of a pigmented melanocytic nevus, histologically confirmed, after hair removal treatment with IPL. The use of lasers and IPL is a common procedure used by dermatologists and even other professions for the treatment of cosmetically troubling skin conditions. The main advantage of such treatment is a reduction of surgical scars, thus producing a favorable cosmetic outcome, but a major limitation is that histopathologic diagnosis is not usually obtained prior to treatment. Such devices should be carefully used in patients with potentially dangerous melanocytic lesions. We also review the recent literature regarding inadequate treatment of melanocytic lesions with lasers. Copyright © 2012 S. Karger AG, Basel.

Cytoarchitecture and Ultrastructure of Neural Stem Cell Niches and Neurogenic Complexes Maintaining Adult Neurogenesis in the Olfactory Midbrain of Spiny Lobsters, Panulirus argus

PubMed Central

Schmidt, Manfred; Derby, Charles D.

2013-01-01

New interneurons are continuously generated in small proliferation zones within neuronal somata clusters in the olfactory deutocerebrum of adult decapod crustaceans. Each proliferation zone is connected to a clump of cells containing one neural stem cell (i.e., adult neuroblast), thus forming a “neurogenic complex.” Here we provide a detailed analysis of the cytoarchitecture of neurogenic complexes in adult spiny lobsters, Panulirus argus, based on transmission electron microscopy and labeling with cell-type-selective markers. The clump of cells is composed of unique bipolar clump-forming cells that collectively completely envelop the adult neuroblast and are themselves ensheathed by a layer of processes of multipolar cell body glia. An arteriole is attached to the clump of cells, but dye perfusion experiments show that hemolymph has no access to the interior of the clump of cells. Thus, the clump of cells fulfills morphological criteria of a protective stem cell niche, with clump-forming cells constituting the adult neuroblast’s microenvironment together with the cell body glia processes separating it from other tissue components. Bromodeoxyuridine pulse-chase experiments with short survival times suggest that adult neuroblasts are not quiescent but rather cycle actively during daytime. We propose a cell lineage model in which an asymmetrically dividing adult neuroblast repopulates the pool of neuronal progenitor cells in the associated proliferation zone. In conclusion, as in mammalian brains, adult neurogenesis in crustacean brains is fueled by neural stem cells that are maintained by stem cell niches that preserve elements of the embryonic microenvironment and contain glial and vascular elements. PMID:21523781

Cytoarchitecture and ultrastructure of neural stem cell niches and neurogenic complexes maintaining adult neurogenesis in the olfactory midbrain of spiny lobsters, Panulirus argus.

PubMed

Schmidt, Manfred; Derby, Charles D

2011-08-15

New interneurons are continuously generated in small proliferation zones within neuronal somata clusters in the olfactory deutocerebrum of adult decapod crustaceans. Each proliferation zone is connected to a clump of cells containing one neural stem cell (i.e., adult neuroblast), thus forming a "neurogenic complex." Here we provide a detailed analysis of the cytoarchitecture of neurogenic complexes in adult spiny lobsters, Panulirus argus, based on transmission electron microscopy and labeling with cell-type-selective markers. The clump of cells is composed of unique bipolar clump-forming cells that collectively completely envelop the adult neuroblast and are themselves ensheathed by a layer of processes of multipolar cell body glia. An arteriole is attached to the clump of cells, but dye perfusion experiments show that hemolymph has no access to the interior of the clump of cells. Thus, the clump of cells fulfills morphological criteria of a protective stem cell niche, with clump-forming cells constituting the adult neuroblast's microenvironment together with the cell body glia processes separating it from other tissue components. Bromodeoxyuridine pulse-chase experiments with short survival times suggest that adult neuroblasts are not quiescent but rather cycle actively during daytime. We propose a cell lineage model in which an asymmetrically dividing adult neuroblast repopulates the pool of neuronal progenitor cells in the associated proliferation zone. In conclusion, as in mammalian brains, adult neurogenesis in crustacean brains is fueled by neural stem cells that are maintained by stem cell niches that preserve elements of the embryonic microenvironment and contain glial and vascular elements. Copyright © 2011 Wiley-Liss, Inc.

Live Imaging of Adult Neural Stem Cells in Rodents

PubMed Central

Ortega, Felipe; Costa, Marcos R.

2016-01-01

The generation of cells of the neural lineage within the brain is not restricted to early development. New neurons, oligodendrocytes, and astrocytes are produced in the adult brain throughout the entire murine life. However, despite the extensive research performed in the field of adult neurogenesis during the past years, fundamental questions regarding the cell biology of adult neural stem cells (aNSCs) remain to be uncovered. For instance, it is crucial to elucidate whether a single aNSC is capable of differentiating into all three different macroglial cell types in vivo or these distinct progenies constitute entirely separate lineages. Similarly, the cell cycle length, the time and mode of division (symmetric vs. asymmetric) that these cells undergo within their lineage progression are interesting questions under current investigation. In this sense, live imaging constitutes a valuable ally in the search of reliable answers to the previous questions. In spite of the current limitations of technology new approaches are being developed and outstanding amount of knowledge is being piled up providing interesting insights in the behavior of aNSCs. Here, we will review the state of the art of live imaging as well as the alternative models that currently offer new answers to critical questions. PMID:27013941

Resolving stem and progenitor cells in the adult mouse incisor through gene co-expression analysis

PubMed Central

Seidel, Kerstin; Marangoni, Pauline; Tang, Cynthia; Houshmand, Bahar; Du, Wen; Maas, Richard L; Murray, Steven; Oldham, Michael C; Klein, Ophir D

2017-01-01

Investigations into stem cell-fueled renewal of an organ benefit from an inventory of cell type-specific markers and a deep understanding of the cellular diversity within stem cell niches. Using the adult mouse incisor as a model for a continuously renewing organ, we performed an unbiased analysis of gene co-expression relationships to identify modules of co-expressed genes that represent differentiated cells, transit-amplifying cells, and residents of stem cell niches. Through in vivo lineage tracing, we demonstrated the power of this approach by showing that co-expression module members Lrig1 and Igfbp5 define populations of incisor epithelial and mesenchymal stem cells. We further discovered that two adjacent mesenchymal tissues, the periodontium and dental pulp, are maintained by distinct pools of stem cells. These findings reveal novel mechanisms of incisor renewal and illustrate how gene co-expression analysis of intact biological systems can provide insights into the transcriptional basis of cellular identity. DOI: http://dx.doi.org/10.7554/eLife.24712.001 PMID:28475038

Hypoxia-induced HIF1α targets in melanocytes reveal a molecular profile associated with poor melanoma prognosis

PubMed Central

Loftus, Stacie K.; Baxter, Laura L.; Cronin, Julia C.; Fufa, Temesgen D.; Pavan, William J.

2017-01-01

Summary Hypoxia and HIF1α signaling direct tissue-specific gene responses regulating tumor progression, invasion and metastasis. By integrating HIF1α knockdown and hypoxia-induced gene expression changes, this study identifies a melanocyte-specific, HIF1α-dependent/hypoxia-responsive gene expression signature. Integration of these gene expression changes with HIF1α ChIP-Seq analysis identifies 81 HIF1α direct target genes in melanocytes. The expression levels for ten of the HIF1α direct targets – GAPDH, PKM, PPAT, DARS, DTWD1, SEH1L, ZNF292, RLF, AGTRAP, and GPC6 – are significantly correlated with reduced time of Disease Free Status (DFS) in melanoma by logistic regression (P-value =0.0013) and ROC curve analysis (AUC= 0.826, P-value<0.0001). This HIF1α-regulated profile defines a melanocyte-specific response under hypoxia, and demonstrates the role of HIF1α as an invasive cell state gatekeeper in regulating cellular metabolism, chromatin and transcriptional regulation, vascularization and invasion. PMID:28168807

Melanosomes are transferred from melanocytes to keratinocytes through the processes of packaging, release, uptake, and dispersion.

PubMed

Ando, Hideya; Niki, Yoko; Ito, Masaaki; Akiyama, Kaoru; Matsui, Mary S; Yarosh, Daniel B; Ichihashi, Masamitsu

2012-04-01

Recent studies have described the role of shedding vesicles as physiological conveyers of intracellular components between neighboring cells. Here we report that melanosomes are one example of shedding vesicle cargo, but are processed by a previously unreported mechanism. Pigment globules were observed to be connected to the filopodia of melanocyte dendrites, which have previously been shown to be conduits for melanosomes. Pigment globules containing multiple melanosomes were released from various areas of the dendrites of normal human melanocytes derived from darkly pigmented skin. The globules were then captured by the microvilli of normal human keratinocytes, also derived from darkly pigmented skin, which incorporated them in a protease-activated receptor-2 (PAR-2)-dependent manner. After the pigment globules were ingested by the keratinocytes, the membrane that surrounded each melanosome cluster was gradually degraded, and the individual melanosomes then spread into the cytosol and were distributed primarily in the perinuclear area of each keratinocyte. These results suggest a melanosome transfer pathway wherein melanosomes are transferred from melanocytes to keratinocytes via the shedding vesicle system. This packaging system generates pigment globules containing multiple melanosomes in a unique manner.

Lineage analysis of quiescent regenerative stem cells in the adult brain by genetic labelling reveals spatially restricted neurogenic niches in the olfactory bulb.

PubMed

Giachino, Claudio; Taylor, Verdon

2009-07-01

The subventricular zone (SVZ) of the lateral ventricles is the major neurogenic region in the adult mammalian brain, harbouring neural stem cells within defined niches. The identity of these stem cells and the factors regulating their fate are poorly understood. We have genetically mapped a population of Nestin-expressing cells during postnatal development to study their potential and fate in vivo. Taking advantage of the recombination characteristics of a nestin::CreER(T2) allele, we followed a subpopulation of neural stem cells and traced their fate in a largely unrecombined neurogenic niche. Perinatal nestin::CreER(T2)-expressing cells give rise to multiple glial cell types and neurons, as well as to stem cells of the adult SVZ. In the adult SVZ nestin::CreER(T2)-expressing neural stem cells give rise to several neuronal subtypes in the olfactory bulb (OB). We addressed whether the same population of neural stem cells play a role in SVZ regeneration. Following anti-mitotic treatment to eliminate rapidly dividing progenitors, relatively quiescent nestin::CreER(T2)-targeted cells are spared and contribute to SVZ regeneration, generating new proliferating precursors and neuroblasts. Finally, we have identified neurogenic progenitors clustered in ependymal-like niches within the rostral migratory stream (RMS) of the OB. These OB-RMS progenitors generate neuroblasts that, upon transplantation, graft, migrate and differentiate into granule and glomerular neurons. In summary, using conditional lineage tracing we have identified neonatal cells that are the source of neurogenic and regenerative neural stem cells in the adult SVZ and occupy a novel neurogenic niche in the OB.

Plasma immunoreactive beta-melanocyte-stimulating hormone and skin pigmentation in chronic renal failure.

PubMed Central

Smith, A G; Shuster, S; Comaish, J S; Plummer, N A; Thody, A J; Alvarez-Ude, F; Kerr, D N

1975-01-01

Plasma immunoreactive beta-melanocyte stimulating hormone (beta-MSH) concentrations were greatly increased in patients with chronic renal failure. There was no correlation between the severity of the renal failure or the degree of pigmentation and the plasma beta-MSH levels. PMID:1125653

Glycoprotein nonmetastatic melanoma protein b, a melanocytic cell marker, is a melanosome-specific and proteolytically released protein

PubMed Central

Hoashi, Toshihiko; Sato, Shinichi; Yamaguchi, Yuji; Passeron, Thierry; Tamaki, Kunihiko; Hearing, Vincent J.

2010-01-01

Melanosomes are organelles specialized for the production of melanin pigment and are specifically produced by melanocytic cells. More than 150 pigmentation-related genes have been identified, including glycoprotein nonmetastatic melanoma protein b (GPNMB). A recent proteomics analysis revealed that GPNMB is localized in melanosomes, and GPNMB is a membrane-bound glycoprotein that shows high homology with a well-known melanosomal structural protein, Pmel17/gp100. In this study, we show that GPNMB is expressed in melanocytes of normal human skin, as well as in human melanoma cells. GPNMB is heavily glycosylated and is enriched in mature (stage III and IV) melanosomes in contrast to MART-1 and Pmel17, which are abundant in early (stage I and II) melanosomes. MART-1 and Pmel17 play critical roles in the maturation of early melanosomes; thus, we speculate that GPNMB might be important in the functions of late melanosomes, possibly their transport and/or transfer to keratinocytes. We also demonstrate that a secreted form of GPNMB is released by ectodomain shedding from the largely Golgi-modified form of GPNMB and that the PKC and Ca2+ intracellular signaling pathways regulate that shedding. We conclude that GPNMB is a melanosomal protein that is released by proteolytic ectodomain shedding and might be a useful and specific histological marker of melanocytic cells.—Hoashi, T., Sato, S., Yamaguchi, Y., Passeron, T., Tamaki, K., Hearing, V. J. Glycoprotein nonmetastatic melanoma protein b, a melanocytic cell marker, is a melanosome-specific and proteolytically released protein. PMID:20056711

A genetic platform to model sarcomagenesis from primary adult mesenchymal stem cells

PubMed Central

Guarnerio, Jlenia; Riccardi, Luisa; Taulli, Riccardo; Maeda, Takahiro; Wang, Guocan; Hobbs, Robin M.; Song, Min Sup; Sportoletti, Paolo; Bernardi, Rosa; Bronson, Roderick T.; Castillo-Martin, Mireia; Cordon-Cardo, Carlos; Lunardi, Andrea; Pandolfi, Pier Paolo

2015-01-01

The regulatory factors governing adult mesenchymal stem cells (MSCs) physiology and their tumorigenic potential are still largely unknown, which substantially delays the identification of effective therapeutic approaches for the treatment of aggressive and lethal form of MSC-derived mesenchymal tumors, such as undifferentiated sarcomas. Here we have developed a novel platform to screen and quickly identify genes and pathways responsible for adult MSCs transformation, modeled undifferentiated sarcoma in vivo, and, ultimately, tested the efficacy of targeting the identified oncopathways. Importantly, by taking advantage of this new platform, we demonstrate the key role of an aberrant LRF-DLK1-SOX9 pathway in the pathogenesis of undifferentiated sarcoma with important therapeutic implications. PMID:25614485

RUTBC1 Functions as a GTPase-activating Protein for Rab32/38 and Regulates Melanogenic Enzyme Trafficking in Melanocytes.

PubMed

Marubashi, Soujiro; Shimada, Hikaru; Fukuda, Mitsunori; Ohbayashi, Norihiko

2016-01-15

Two cell type-specific Rab proteins, Rab32 and Rab38 (Rab32/38), have been proposed as regulating the trafficking of melanogenic enzymes, including tyrosinase and tyrosinase-related protein 1 (Tyrp1), to melanosomes in melanocytes. Like other GTPases, Rab32/38 function as switch molecules that cycle between a GDP-bound inactive form and a GTP-bound active form; the cycle is thought to be regulated by an activating enzyme, guanine nucleotide exchange factor (GEF), and an inactivating enzyme, GTPase-activating protein (GAP), which stimulates the GTPase activity of Rab32/38. Although BLOC-3 has already been identified as a Rab32/38-specific GEF that regulates the trafficking of tyrosinase and Tyrp1, no physiological GAP for Rab32/38 in melanocytes has ever been identified, and it has remained unclear whether Rab32/38 is involved in the trafficking of dopachrome tautomerase, another melanogenic enzyme, in mouse melanocytes. In this study we investigated RUTBC1, which was originally characterized as a Rab9-binding protein and GAP for Rab32 and Rab33B in vitro, and the results demonstrated that RUTBC1 functions as a physiological GAP for Rab32/38 in the trafficking of all three melanogenic enzymes in mouse melanocytes. The results of this study also demonstrated the involvement of Rab9A in the regulation of the RUTBC1 localization and in the trafficking of all three melanogenic enzymes. We discovered that either excess activation or inactivation of Rab32/38 achieved by manipulating RUTBC1 inhibits the trafficking of all three melanogenic enzymes. These results collectively indicate that proper spatiotemporal regulation of Rab32/38 is essential for the trafficking of all three melanogenic enzymes in mouse melanocytes. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

RUTBC1 Functions as a GTPase-activating Protein for Rab32/38 and Regulates Melanogenic Enzyme Trafficking in Melanocytes*

PubMed Central

Marubashi, Soujiro; Shimada, Hikaru; Fukuda, Mitsunori; Ohbayashi, Norihiko

2016-01-01

Two cell type-specific Rab proteins, Rab32 and Rab38 (Rab32/38), have been proposed as regulating the trafficking of melanogenic enzymes, including tyrosinase and tyrosinase-related protein 1 (Tyrp1), to melanosomes in melanocytes. Like other GTPases, Rab32/38 function as switch molecules that cycle between a GDP-bound inactive form and a GTP-bound active form; the cycle is thought to be regulated by an activating enzyme, guanine nucleotide exchange factor (GEF), and an inactivating enzyme, GTPase-activating protein (GAP), which stimulates the GTPase activity of Rab32/38. Although BLOC-3 has already been identified as a Rab32/38-specific GEF that regulates the trafficking of tyrosinase and Tyrp1, no physiological GAP for Rab32/38 in melanocytes has ever been identified, and it has remained unclear whether Rab32/38 is involved in the trafficking of dopachrome tautomerase, another melanogenic enzyme, in mouse melanocytes. In this study we investigated RUTBC1, which was originally characterized as a Rab9-binding protein and GAP for Rab32 and Rab33B in vitro, and the results demonstrated that RUTBC1 functions as a physiological GAP for Rab32/38 in the trafficking of all three melanogenic enzymes in mouse melanocytes. The results of this study also demonstrated the involvement of Rab9A in the regulation of the RUTBC1 localization and in the trafficking of all three melanogenic enzymes. We discovered that either excess activation or inactivation of Rab32/38 achieved by manipulating RUTBC1 inhibits the trafficking of all three melanogenic enzymes. These results collectively indicate that proper spatiotemporal regulation of Rab32/38 is essential for the trafficking of all three melanogenic enzymes in mouse melanocytes. PMID:26620560

Transcription analysis in the MeLiM swine model identifies RACK1 as a potential marker of malignancy for human melanocytic proliferation.

PubMed

Egidy, Giorgia; Julé, Sophia; Bossé, Philippe; Bernex, Florence; Geffrotin, Claudine; Vincent-Naulleau, Silvia; Horak, Vratislav; Sastre-Garau, Xavier; Panthier, Jean-Jacques

2008-04-28

Metastatic melanoma is a severe disease. Few experimental animal models of metastatic melanoma exist. MeLiM minipigs exhibit spontaneous melanoma. Cutaneous and metastatic lesions are histologically similar to human's. However, most of them eventually spontaneously regress. Our purpose was to investigate whether the MeLiM model could reveal markers of malignancy in human melanocytic proliferations. We compared the serial analysis of gene expression (SAGE) between normal pig skin melanocytes and melanoma cells from an early pulmonary metastasis of MeLiM minipigs. Tag identification revealed 55 regulated genes, including GNB2L1 which was found upregulated in the melanoma library. In situ hybridisation confirmed GNB2L1 overexpression in MeLiM melanocytic lesions. GNB2L1 encodes the adaptor protein RACK1, recently shown to influence melanoma cell lines tumorigenicity. We studied the expression of RACK1 by immunofluorescence and confocal microscopy in tissues specimens of normal skin, in cutaneous and metastatic melanoma developped in MeLiM minipigs and in human patients. In pig and human samples, the results were similar. RACK1 protein was not detected in normal epidermal melanocytes. By contrast, RACK1 signal was highly increased in the cytoplasm of all melanocytic cells of superficial spreading melanoma, recurrent dermal lesions and metastatic melanoma. RACK1 partially colocalised with activated PKCalphabeta. In pig metastases, additional nuclear RACK1 did not associate to BDNF expression. In human nevi, the RACK1 signal was low. RACK1 overexpression detected in situ in human melanoma specimens characterized cutaneous and metastatic melanoma raising the possibility that RACK1 can be a potential marker of malignancy in human melanoma. The MeLiM strain provides a relevant model for exploring mechanisms of melanocytic malignant transformation in humans. This study may contribute to a better understanding of melanoma pathophysiology and to progress in diagnosis.

Increased intracellular pH is necessary for adult epithelial and embryonic stem cell differentiation

PubMed Central

Azimova, Dinara R.

2016-01-01

Despite extensive knowledge about the transcriptional regulation of stem cell differentiation, less is known about the role of dynamic cytosolic cues. We report that an increase in intracellular pH (pHi) is necessary for the efficient differentiation of Drosophila adult follicle stem cells (FSCs) and mouse embryonic stem cells (mESCs). We show that pHi increases with differentiation from FSCs to prefollicle cells (pFCs) and follicle cells. Loss of the Drosophila Na+–H+ exchanger DNhe2 lowers pHi in differentiating cells, impairs pFC differentiation, disrupts germarium morphology, and decreases fecundity. In contrast, increasing pHi promotes excess pFC cell differentiation toward a polar/stalk cell fate through suppressing Hedgehog pathway activity. Increased pHi also occurs with mESC differentiation and, when prevented, attenuates spontaneous differentiation of naive cells, as determined by expression of microRNA clusters and stage-specific markers. Our findings reveal a previously unrecognized role of pHi dynamics for the differentiation of two distinct types of stem cell lineages, which opens new directions for understanding conserved regulatory mechanisms. PMID:27821494

Store-Operated Calcium Entries Control Neural Stem Cell Self-Renewal in the Adult Brain Subventricular Zone.

PubMed

Domenichini, Florence; Terrié, Elodie; Arnault, Patricia; Harnois, Thomas; Magaud, Christophe; Bois, Patrick; Constantin, Bruno; Coronas, Valérie

2018-05-01

The subventricular zone (SVZ) is the major stem cell niche in the brain of adult mammals. Within this region, neural stem cells (NSC) proliferate, self-renew and give birth to neurons and glial cells. Previous studies underlined enrichment in calcium signaling-related transcripts in adult NSC. Because of their ability to mobilize sustained calcium influxes in response to a wide range of extracellular factors, store-operated channels (SOC) appear to be, among calcium channels, relevant candidates to induce calcium signaling in NSC whose cellular activities are continuously adapted to physiological signals from the microenvironment. By Reverse Transcription Polymerase Chain Reaction (RT-PCR), Western blotting and immunocytochemistry experiments, we demonstrate that SVZ cells express molecular actors known to build up SOC, namely transient receptor potential canonical 1 (TRPC1) and Orai1, as well as their activator stromal interaction molecule 1 (STIM1). Calcium imaging reveals that SVZ cells display store-operated calcium entries. Pharmacological blockade of SOC with SKF-96365 or YM-58483 (also called BTP2) decreases proliferation, impairs self-renewal by shifting the type of SVZ stem cell division from symmetric proliferative to asymmetric, thereby reducing the stem cell population. Brain section immunostainings show that TRPC1, Orai1, and STIM1 are expressed in vivo, in SOX2-positive SVZ NSC. Injection of SKF-96365 in brain lateral ventricle diminishes SVZ cell proliferation and reduces the ability of SVZ cells to form neurospheres in vitro. The present study combining in vitro and in vivo approaches uncovers a major role for SOC in the control of SVZ NSC population and opens new fields of investigation for stem cell biology in health and disease. Stem Cells 2018;36:761-774. © AlphaMed Press 2018.

Low levels of endogenous or X-ray-induced DNA double-strand breaks activate apoptosis in adult neural stem cells.

PubMed

Barazzuol, Lara; Rickett, Nicole; Ju, Limei; Jeggo, Penny A

2015-10-01

The embryonic neural stem cell compartment is characterised by rapid proliferation from embryonic day (E)11 to E16.5, high endogenous DNA double-strand break (DSB) formation and sensitive activation of apoptosis. Here, we ask whether DSBs arise in the adult neural stem cell compartments, the sub-ventricular zone (SVZ) of the lateral ventricles and the sub-granular zone (SGZ) of the hippocampal dentate gyrus, and whether they activate apoptosis. We used mice with a hypomorphic mutation in DNA ligase IV (Lig4(Y288C)), ataxia telangiectasia mutated (Atm(-/-)) and double mutant Atm(-/-)/Lig4(Y288C) mice. We demonstrate that, although DSBs do not arise at a high frequency in adult neural stem cells, the low numbers of DSBs that persist endogenously in Lig4(Y288C) mice or that are induced by low radiation doses can activate apoptosis. A temporal analysis shows that DSB levels in Lig4(Y288C) mice diminish gradually from the embryo to a steady state level in adult mice. The neonatal SVZ compartment of Lig4(Y288C) mice harbours diminished DSBs compared to its differentiated counterpart, suggesting a process selecting against unfit stem cells. Finally, we reveal high endogenous apoptosis in the developing SVZ of wild-type newborn mice. © 2015. Published by The Company of Biologists Ltd.

Differentiation of Neonatal Human-Induced Pluripotent Stem Cells to Prostate Epithelial Cells: A Model to Study Prostate Cancer Development

DTIC Science & Technology

2013-06-01

38, 40, 41]. Because these “ mela - noma stem cells” (MSC) are sometimes so numerous, some have argued that the CSC model may not apply to melanoma...40]. There are data from two groups indicating that mela - noma lesions contain a CSC subset character- ized by CD271 expression [25, 26]. In a...neuronal proteins and neuron- like differentiation has been long recognized in neoplastic melanocytes [46, 47]. Certain mela - noma cell lines that

Acute Inhibition of MEK Suppresses Congenital Melanocytic Nevus Syndrome in a Murine Model Driven by Activated NRAS and Wnt Signaling.

PubMed

Pawlikowski, Jeffrey S; Brock, Claire; Chen, Sheau-Chiann; Al-Olabi, Lara; Nixon, Colin; McGregor, Fiona; Paine, Simon; Chanudet, Estelle; Lambie, Wendy; Holmes, William M; Mullin, James M; Richmond, Ann; Wu, Hong; Blyth, Karen; King, Ayala; Kinsler, Veronica A; Adams, Peter D

2015-08-01

Congenital melanocytic nevus (CMN) syndrome is the association of pigmented melanocytic nevi with extra-cutaneous features, classically melanotic cells within the central nervous system, most frequently caused by a mutation of NRAS codon 61. This condition is currently untreatable and carries a significant risk of melanoma within the skin, brain, or leptomeninges. We have previously proposed a key role for Wnt signaling in the formation of melanocytic nevi, suggesting that activated Wnt signaling may be synergistic with activated NRAS in the pathogenesis of CMN syndrome. Some familial pre-disposition suggests a germ-line contribution to CMN syndrome, as does variability of neurological phenotypes in individuals with similar cutaneous phenotypes. Accordingly, we performed exome sequencing of germ-line DNA from patients with CMN to reveal rare or undescribed Wnt-signaling alterations. A murine model harboring activated NRAS(Q61K) and Wnt signaling in melanocytes exhibited striking features of CMN syndrome, in particular neurological involvement. In the first model of treatment for this condition, these congenital, and previously assumed permanent, features were profoundly suppressed by acute post-natal treatment with a MEK inhibitor. These data suggest that activated NRAS and aberrant Wnt signaling conspire to drive CMN syndrome. Post-natal MEK inhibition is a potential candidate therapy for patients with this debilitating condition.

A comparative study of the effects of different low-level lasers on the proliferation, viability, and migration of human melanocytes in vitro.

PubMed

AlGhamdi, Khalid M; Kumar, Ashok; Ashour, Abdelkader E; AlGhamdi, Attieh A

2015-07-01

The aim of this study was to investigate the effects of different low-level laser therapies (LLLTs) of various wavelengths and energies on normal cultured human melanocytes. Various studies have shown the effects of LLLs on various types of cultured cells. Presently, little is known about the biological effects of LLLTs on melanocytes. Melanocytes were exposed to LLLT at 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, or 5.0 J/cm(2) using a blue (457 nm), red (635 nm), or ultraviolet (UV) (355 nm) laser. Melanocyte viability, proliferation, and migration were monitored at 72 h after irradiation. The blue (P < 0.001) and red (P < 0.001 and P < 0.01) lasers significantly enhanced viability at 0.5 to 2.0 J/cm(2), whereas the UV laser (P < 0.001) could significantly enhance viability only at 0.5 and 1.0 J/cm(2) compared with controls. The blue and red lasers also significantly enhanced the proliferation of the melanocytes at 0.5 to 2.0 J/cm(2) (P < 0.001), and the UV laser significantly enhanced proliferation at 0.5 to 1.5 J/cm(2) (P < 0.001 and P < 0.01) compared with controls. The blue laser significantly enhanced melanocyte migration at 0.5 to 4.0 J/cm(2) (P < 0.001 to P < 0.05), but the red (P < 0.001 and P < 0.01) and UV (P < 0.001 to P < 0.05) lasers could significantly enhance such migration at 0.5 to 1.0 J/cm(2) and 0.5 to 2.0 J/cm(2), respectively, compared with controls. LLLT at low energy densities is able to significantly increase melanocyte viability, proliferation, and migration in vitro, and at higher energy densities, it gives non-stimulatory results. Additionally, the blue laser was the best among the three lasers. These findings might have potential application in vitiligo treatment in future.

Cell Growth Characteristics, Differentiation Frequency, and Immunophenotype of Adult Ear Mesenchymal Stem Cells

PubMed Central

Staszkiewicz, Jaroslaw; Frazier, Trivia P.; Rowan, Brian G.; Bunnell, Bruce A.; Chiu, Ernest S.; Gimble, Jeffrey M.

2010-01-01

Ear mesenchymal stem cells (EMSCs) represent a readily accessible population of stem-like cells that are adherent, clonogenic, and have the ability to self-renew. Previously, we have demonstrated that they can be induced to differentiate into adipocyte, osteocyte, chondrocyte, and myocyte lineages. The purpose of the current study was to characterize the growth kinetics of the cells and to determine their ability to form colonies of fibroblasts, adipocytes, osteocytes, and chondrocytes. In addition, the immunophenotypes of freshly isolated and culture-expanded cells were evaluated. From 1 g of tissue, we were able to isolate an average of 7.8 × 106 cells exhibiting a cell cycle length of ∼2–3 days. Colony-forming unit (CFU) assays indicated high proliferation potential, and confirmed previously observed multipotentiality of the cells. Fluorescence-activated cell sorting (FACS) showed that EMSCs were negative for hematopoietic markers (CD4, CD45), proving that they did not derive from circulating hematopoietic cells. The FACS analyses also showed high expression of stem cell antigen-1 (Sca-1) with only a minor population of cells expressing CD117, thus identifying Sca-1 as the more robust stem cell biomarker. Additionally, flow cytometry data revealed that the expression patterns of hematopoietic, stromal, and stem cell markers were maintained in the passaged EMSCs, consistent with the persistence of an undifferentiated state. This study indicates that EMSCs provide an alternative model for in vitro analyses of adult mesenchymal stem cells (MSCs). Further studies will be necessary to determine their utility for tissue engineering and regenerative medical applications. PMID:19400629

Lgr proteins in epithelial stem cell biology.

PubMed

Barker, Nick; Tan, Shawna; Clevers, Hans

2013-06-01

The ultimate success of global efforts to exploit adult stem cells for regenerative medicine will depend heavily on the availability of robust, highly selective stem cell surface markers that facilitate the isolation of stem cells from human tissues. Any subsequent expansion or manipulation of isolated stem cells will also require an intimate knowledge of the mechanisms that regulate these cells, to ensure maintenance of their regenerative capacities and to minimize the risk of introducing undesirable growth traits that could pose health risks for patients. A subclass of leucine-rich repeat-containing G-protein-coupled receptor (Lgr) proteins has recently gained prominence as adult stem cell markers with crucial roles in maintaining stem cell functions. Here, we discuss the major impact that their discovery has had on our understanding of adult stem cell biology in various self-renewing tissues and in accelerating progress towards the development of effective stem cell therapies.

Oxidation levels differentially impact melanocytes: low versus high concentration of hydrogen peroxide promotes melanin synthesis and melanosome transfer.

PubMed

Tang, Luyan; Li, Jian; Lin, Xiao; Wu, Wenyu; Kang, Kefei; Fu, Wenwen

2012-01-01

UVB light can generate potentially harmful hydrogen peroxide (H(2)O(2)) in vivo, but it can also promote the beneficial proliferation and migration of melanocytes. The successful use of UVB monotherapy for treatment of vitiligo suggests that H(2)O(2) may have a biphasic effect on melanin synthesis and melanosome transfer. To study the beneficial role of H(2)O(2) on melanogenesis and melanosome transport in living melanocytes and keratinocytes. A co-culture system model was constructed using the primary human melanocytes and keratinocytes. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was used to determine cell proliferation, NaOH was used to determine the melanin content, and real-time PCR was used to determine tyrosinase expression. Western blot was used to determine Rab-27A and protease-activated receptor 2 (PAR-2) expression. This study demonstrated that tyrosinase was activated by low concentrations of H(2)O(2) (≤0.3 mM); however, this activity was downregulated by high concentrations of H(2)O(2) (>0.3 mM). Activation of high levels of melanin synthesis was induced when cells were treated with low concentrations of H(2)O(2) (0.3 mM). Further observation using an in vitro co-culture system of fluorescein (carboxyfluorescein diacetate succinimidyl ester, CFDA-SE)-labeled melanocytes and keratinocytes indicated that melanosome transfer occurred in normal human epidermal melanocytes. Fluorescence microscopy revealed increased melanosome transfer into keratinocytes treated with 0.3 mM H(2)O(2) in the co-culture compared to the control. Examination of melanosomes in the keratinocytes by flow cytometry confirmed these results. Furthermore, treatment with H(2)O(2) (0.3 mM) upregulated the expression of Rab-27A and PAR-2, significant proteins involved in melanosome transfer, according to Western blot. These results confirmed that low concentration levels of H(2)O(2) play a major role in the regulation of human pigmentation by increasing

Sorting of Pmel17 to melanosomes through the plasma membrane by AP1 and AP2: evidence for the polarized nature of melanocytes

PubMed Central

Valencia, Julio C.; Watabe, Hidenori; Chi, An; Rouzaud, Francois; Chen, Kevin G.; Vieira, Wilfred D.; Takahashi, Kaoruko; Yamaguchi, Yuji; Berens, Werner; Nagashima, Kunio; Shabanowitz, Jeffrey; Hunt, Donald F.; Appella, Ettore; Hearing, Vincent J.

2015-01-01

Summary Adaptor proteins (AP) play important roles in the sorting of proteins from the trans-Golgi network, but how they function in the sorting of various melanosome-specific proteins such as Pmel17, an essential structural component of melanosomes, in melanocytes is unknown. We characterized the processing and trafficking of Pmel17 via adaptor protein complexes within melanocytic cells. Proteomics analysis detected Pmel17, AP1 and AP2, but not AP3 or AP4 in early melanosomes. Real-time PCR, immunolabeling and tissue in-situ hybridization confirmed the coexpression of AP1 isoforms μ1A and μ1B (expressed only in polarized cells) in melanocytes and keratinocytes, but expression of μ1B is missing in some melanoma cell lines. Transfection with AP1 isoforms (μ1A or μ1B) showed two distinct distribution patterns that involved Pmel17, and only μ1B was able to restore the sorting of Pmel17 to the plasma membrane in cells lacking μ1B expression. Finally, we established that expression of μ1B is regulated physiologically in melanocytes by UV radiation or DKK1. These results show that Pmel17 is sorted to melanosomes by various intracellular routes, directly or indirectly through the plasma membrane, and the presence of basolateral elements in melanocytes suggests their polarized nature. PMID:16492709

Fourier domain optical coherence tomographic and auto-fluorescence findings in indeterminate choroidal melanocytic lesions.

PubMed

Singh, Arun D; Belfort, Rubens N; Sayanagi, Kaori; Kaiser, Peter K

2010-04-01

To compare detection rates of drusen and subretinal fluid by Fourier domain optical coherence tomography (FD OCT) and orange pigment by fundus autofluorescence (FAF) with ophthalmoscopy in indeterminate choroidal melanocytic lesions. In a consecutive case series of 38 patients with indeterminate choroidal melanocytic lesion that would have been categorised as a small tumour according to the size-based nomenclature used in the Collaborative Ocular Melanoma Study, each eye was submitted to ophthalmoscopic examination, FD OCT and FAF. The presence of drusen, subretinal fluid and orange pigment was recorded for each lesion by a single observer at the time of initial ophthalmoscopic evaluation and on fundus photographs. FD OCT and autofluorescence images were reviewed in all cases in a masked fashion. The ophthalmoscopic examination revealed drusen in 42%, subretinal fluid in 53% and orange pigment in 50% of patients. FD-OCT detected drusen in 45% and subretinal fluid in 58% of cases, and FAF detected orange pigment in 58% of cases. Based on the McNemar test, none of the differences were statistically significant at the 0.05 level. FD OCT and FAF complement clinical examination by verifying and documenting retinal and RPE changes associated with indeterminate choroidal melanocytic lesions. The detection rates by FD OCT and FAF of important qualitative prognostic factors appear to be equivalent to ophthalmoscopy by a trained observer. Once validated in a larger number of patients, FD OCT and FAF findings can be incorporated into diagnostic algorithms.

Using Dermoscopic Criteria and Patient-Related Factors for the Management of Pigmented Melanocytic Nevi

PubMed Central

Zalaudek, Iris; Docimo, Giovanni; Argenziano, Giuseppe

2010-01-01

Objective: To review recent dermoscopy studies that provide new insights into the evolution of nevi and their patterns of pigmentation as they contribute to the diagnosis of nevi and the management of pigmented melanocytic nevi. Data Sources: Data for this article were identified by searching the English and German literature by Medline and Journals@Ovid search for the period 1950 to January 2009. Study Selection: The following relevant terms were used: dermoscopy, dermatoscopy, epiluminescence microscopy (ELM), surface microscopy, digital dermoscopy, digital dermatoscopy, digital epiluminescence microscopy, digital surface microscopy, melanocytic skin lesion, nevi, and pigmented skin lesions. There were no exclusion criteria. Data Synthesis: The dermoscopic diagnosis of nevi relies on the following 4 criteria (each of which is characterized by 4 variables): (1) color (black, brown, gray, and blue); (2) pattern (globular, reticular, starburst, and homogeneous blue pattern); (3) pigment distribution (multifocal, central, eccentric, and uniform); and (4) special sites (face, acral areas, nail, and mucosa). In addition, the following 6 factors related to the patient might influence the pattern of pigmentation of the individual nevi: age, skin type, history of melanoma, UV exposure, pregnancy, and growth dynamics. Conclusions: The 4×4×6 “rule” may help clinicians remember the basic dermoscopic criteria of nevi and the patient-related factors influencing their patterns. Dermoscopy is a useful technique for diagnosing melanocytic nevi, but the clinician should take additional factors into consideration to optimize the management of cases of pigmented lesions. PMID:19620566

Complementary epistasis involving Sr12 explains adult plant resistance to stem rust in Thatcher wheat (Triticum aestivum L.).

PubMed

Rouse, Matthew N; Talbert, Luther E; Singh, Davinder; Sherman, Jamie D

2014-07-01

Quantitative trait loci conferring adult plant resistance to Ug99 stem rust in Thatcher wheat display complementary gene action suggesting multiple quantitative trait loci are needed for effective resistance. Adult plant resistance (APR) in wheat (Triticum aestivum L.) to stem rust, caused by Puccinia graminis f. sp. tritici (Pgt), is desirable because this resistance can be Pgt race non-specific. Resistance derived from cultivar Thatcher can confer high levels of APR to the virulent Pgt race TTKSK (Ug99) when combined with stem rust resistance gene Sr57 (Lr34). To identify the loci conferring APR in Thatcher, we evaluated 160 RILs derived from Thatcher crossed to susceptible cultivar McNeal for field stem rust reaction in Kenya for two seasons and in St. Paul for one season. All RILs and parents were susceptible as seedlings to race TTKSK. However, adult plant stem rust severities in Kenya varied from 5 to 80 %. Composite interval mapping identified four quantitative trait loci (QTL). Three QTL were inherited from Thatcher and one, Sr57, was inherited from McNeal. The markers closest to the QTL peaks were used in an ANOVA to determine the additive and epistatic effects. A QTL on 3BS was detected in all three environments and explained 27-35 % of the variation. The peak of this QTL was at the same location as the Sr12 seedling resistance gene effective to race SCCSC. Epistatic interactions were significant between Sr12 and QTL on chromosome arms 1AL and 2BS. Though Sr12 cosegregated with the largest effect QTL, lines with Sr12 were not always resistant. The data suggest that Sr12 or a linked gene, though not effective to race TTKSK alone, confers APR when combined with other resistance loci.

Abundance of the benign melanocytic universe: Dermoscopic-histopathological correlation in nevi.

PubMed

Woltsche, Nora; Schmid-Zalaudek, Karin; Deinlein, Teresa; Rammel, Katrin; Hofmann-Wellenhof, Rainer; Zalaudek, Iris

2017-05-01

The broad universe of "melanocytic nevi" includes a variety of different subtypes, which can be classified either due to their morphology, epidemiology, genetic alterations or risk for developing melanoma. Regarding morphology, on the one hand macroscopic/clinical and on the other hand histopathological appearance were used to subdivide in the past, often resulting in confusion and poor interobserver agreement, while nowadays dermoscopy presents the clinician's precious bridge between naked-eye examination and histopathological diagnostics, allowing prediction of the lesions' histopathology, follow up and monitoring over time without need of excision. The non-invasive dermoscopic examination relies on the assessment of colors, patterns and the distribution of both within a cutaneous lesion. Until today, the correspondence of certain dermoscopic colors and patterns to certain histopathological correlates has been reported for a huge amount of different cutaneous lesions. Moreover, the correspondence of certain dermoscopic features to certain body sites, age groups and pigmentary traits, but also to specific genetic alterations in lesions, has been broadly investigated. Dermoscopy has led us to a new understanding of melanocytic nevi's biology and evolution and, last but not least, to a new classification system, which we want to present herein. © 2017 Japanese Dermatological Association.

Hip prostheses in young adults. Surface prostheses and short-stem prostheses.

PubMed

Gallart, X; Riba, J; Fernández-Valencia, J A; Bori, G; Muñoz-Mahamud, E; Combalia, A

The poor results obtained in young patients when using a conventional prosthesis led to the resurgence of hip resurfacing to find less invasive implants for the bone. Young patients present a demand for additional activity, which makes them a serious challenge for the survival of implants. In addition, new information technologies contribute decisively to the preference for non-cemented prostheses. Maintaining quality of life, preserving the bone and soft tissues, as well as achieving a very stable implant, are the goals of every hip orthopaedic surgeon for these patients. The results in research point to the use of smaller prostheses, which use the metaphyseal zone more and less the diaphyseal zone, and hence the large number of the abovementioned short stem prostheses. Both models are principally indicated in the young adult. Their revision should be a more simple operation, but this is only true for hip resurfacing, not for short stems. Copyright © 2017 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

"Sky Full of Stars" Pattern: Dermoscopic Findings in a Desmoplastic Giant Congenital Melanocytic Nevus.

PubMed

Martín-Carrasco, Pablo; Bernabeu-Wittel, José; Dominguez-Cruz, Javier; Zulueta Dorado, Teresa; Conejo-Mir Sanchez, Julian

2017-05-01

Desmoplastic giant congenital melanocytic nevus (DGCN) is an uncommon variant of congenital nevus, presenting as a progressive induration and hypopigmentation of the lesion that occasionally causes hair loss and even total or partial disappearance of the nevus. A 6-month-old girl with a giant congenital melanocytic nevus that involved the entire posterior side of the right thigh was seen in our department. Nine months later, the peripheral area of the nevus presented as a marked induration with hypopigmentation. Dermoscopy demonstrated a reticular pattern exclusively located in the perifollicular areas, with a radial distribution from the follicular ostium that mimicked a "sky full of stars." We report a case of DGCN, including a dermoscopic description of the findings noted in the indurated and hypopigmented areas that appear as a "sky full of stars" image. © 2017 Wiley Periodicals, Inc.

Transcription factors in melanocyte development: distinct roles for Pax-3 and Mitf.

PubMed

Hornyak, T J; Hayes, D J; Chiu, L Y; Ziff, E B

2001-03-01

A transgenic mouse model was used to examine the roles of the murine transcription factors Pax-3 and Mitf in melanocyte development. Transgenic mice expressing beta-galactosidase from the dopachrome tautomerase (Dct) promoter were generated and found to express the transgene in developing melanoblasts as early as embryonic day (E) 9.5. These mice express the transgene in a pattern characteristic of endogenous Dct expression. Transgenic mice were intercrossed with two murine coat color mutants, Splotch (Sp), containing a mutation in the murine Pax3 gene, and Mitf(mi), with a mutation in the basic-helix-loop-helix-leucine zipper gene Mitf. Transgenic heterozygous mutant animals were crossed to generate transgenic embryos for analysis. Examination of beta-galactosidase-expressing melanoblasts in mutant embryos reveals that Mitf is required in vivo for survival of melanoblasts up to the migration staging area in neural crest development. Examination of Mitf(mi)/+ embryos shows that there are diminished numbers of melanoblasts in the heterozygous state early in melanocyte development, consistent with a gene dosage-dependent effect upon cell survival. However, quantification and analysis of melanoblast growth during the migratory phase suggests that melanoblasts then increase in number more rapidly in the heterozygous embryo. In contrast to Mitf(mi)/Mitf(mi) embryos, Sp/Sp embryos exhibit melanoblasts that have migrated to characteristic locations along the melanoblast migratory pathway, but are greatly reduced in number compared to control littermates. Together, these results support a model for melanocyte development whereby Pax3 is required to expand a pool of committed melanoblasts or restricted progenitor cells early in development, whereas Mitf facilitates survival of the melanoblast in a gene dosage-dependent manner within and immediately after emigration from the dorsal neural tube, and may also directly or indirectly affect the rate at which melanoblast number

Towards optimization of odonto/osteogenic bioengineering: in vitro comparison of simvastatin, sodium fluoride, melanocyte-stimulating hormone.

PubMed

Zijah, Vahid; Salehi, Roya; Aghazadeh, Marziyeh; Samiei, Mohammad; Alizadeh, Effat; Davaran, Soodabeh

2017-06-01

Tissue engineering has emerged as a potential therapeutic option for dental problems in recent years. One of the policies in tissue engineering is to use both scaffolds and additive factors for enhancing cell responses. This study aims to evaluate and compare the effect of three types of biofactors on poly-caprolactone-poly-ethylene glycol-poly caprolactone (PCL-PEG-PCL) nanofibrous scaffold on human dental pulp stem cell (hDPSCs) engineering. The PCL-PEG-PCL copolymer was synthesized with ring opening polymerization method, and its nanofiber scaffold was prepared by electrospinning method. Nanofibrous scaffold-seeded hDPSCs were treated with sodium fluoride (NaF), melanocyte-stimulating hormone (MSH), or simvastatin (SIM). Non-treated nanofiber seeded cells were utilized as control. The viability, biocompatibility, adhesion, proliferation rate, morphology, osteo/odontogenic potential, and the expression of tissue-specific genes were studied. The results showed that significant higher results demonstrated significant higher adhesive behavior, viability, alizarin red activity, and dentin specific gene expression in MSH- and SIM-treated cells (p < 0.05). This study is unique; in that, it compares the effects of different treatments for optimization of dental tissue engineering.

Automated analysis and classification of melanocytic tumor on skin whole slide images.

PubMed

Xu, Hongming; Lu, Cheng; Berendt, Richard; Jha, Naresh; Mandal, Mrinal

2018-06-01

This paper presents a computer-aided technique for automated analysis and classification of melanocytic tumor on skin whole slide biopsy images. The proposed technique consists of four main modules. First, skin epidermis and dermis regions are segmented by a multi-resolution framework. Next, epidermis analysis is performed, where a set of epidermis features reflecting nuclear morphologies and spatial distributions is computed. In parallel with epidermis analysis, dermis analysis is also performed, where dermal cell nuclei are segmented and a set of textural and cytological features are computed. Finally, the skin melanocytic image is classified into different categories such as melanoma, nevus or normal tissue by using a multi-class support vector machine (mSVM) with extracted epidermis and dermis features. Experimental results on 66 skin whole slide images indicate that the proposed technique achieves more than 95% classification accuracy, which suggests that the technique has the potential to be used for assisting pathologists on skin biopsy image analysis and classification. Copyright © 2018 Elsevier Ltd. All rights reserved.

Regional and stage-specific effects of prospectively purified vascular cells on the adult V-SVZ neural stem cell lineage.

PubMed

Crouch, Elizabeth E; Liu, Chang; Silva-Vargas, Violeta; Doetsch, Fiona

2015-03-18

Adult neural stem cells reside in specialized niches. In the ventricular-subventricular zone (V-SVZ), quiescent neural stem cells (qNSCs) become activated (aNSCs), and generate transit amplifying cells (TACs), which give rise to neuroblasts that migrate to the olfactory bulb. The vasculature is an important component of the adult neural stem cell niche, but whether vascular cells in neurogenic areas are intrinsically different from those elsewhere in the brain is unknown. Moreover, the contribution of pericytes to the neural stem cell niche has not been defined. Here, we describe a rapid FACS purification strategy to simultaneously isolate primary endothelial cells and pericytes from brain microregions of nontransgenic mice using CD31 and CD13 as surface markers. We compared the effect of purified vascular cells from a neurogenic (V-SVZ) and non-neurogenic brain region (cortex) on the V-SVZ stem cell lineage in vitro. Endothelial and pericyte diffusible signals from both regions differentially promote the proliferation and neuronal differentiation of qNSCs, aNSCs, and TACs. Unexpectedly, diffusible cortical signals had the most potent effects on V-SVZ proliferation and neurogenesis, highlighting the intrinsic capacity of non-neurogenic vasculature to support stem cell behavior. Finally, we identify PlGF-2 as an endothelial-derived mitogen that promotes V-SVZ cell proliferation. This purification strategy provides a platform to define the functional and molecular contribution of vascular cells to stem cell niches and other brain regions under different physiological and pathological states. Copyright © 2015 the authors 0270-6474/15/354528-12$15.00/0.

An independent validation of a gene expression signature to differentiate malignant melanoma from benign melanocytic nevi.

PubMed

Clarke, Loren E; Flake, Darl D; Busam, Klaus; Cockerell, Clay; Helm, Klaus; McNiff, Jennifer; Reed, Jon; Tschen, Jaime; Kim, Jinah; Barnhill, Raymond; Elenitsas, Rosalie; Prieto, Victor G; Nelson, Jonathan; Kimbrell, Hillary; Kolquist, Kathryn A; Brown, Krystal L; Warf, M Bryan; Roa, Benjamin B; Wenstrup, Richard J

2017-02-15

Recently, a 23-gene signature was developed to produce a melanoma diagnostic score capable of differentiating malignant and benign melanocytic lesions. The primary objective of this study was to independently assess the ability of the gene signature to differentiate melanoma from benign nevi in clinically relevant lesions. A set of 1400 melanocytic lesions was selected from samples prospectively submitted for gene expression testing at a clinical laboratory. Each sample was tested and subjected to an independent histopathologic evaluation by 3 experienced dermatopathologists. A primary diagnosis (benign or malignant) was assigned to each sample, and diagnostic concordance among the 3 dermatopathologists was required for inclusion in analyses. The sensitivity and specificity of the score in differentiating benign and malignant melanocytic lesions were calculated to assess the association between the score and the pathologic diagnosis. The gene expression signature differentiated benign nevi from malignant melanoma with a sensitivity of 91.5% and a specificity of 92.5%. These results reflect the performance of the gene signature in a diverse array of samples encountered in routine clinical practice. Cancer 2017;123:617-628. © 2016 American Cancer Society. © 2016 Myriad Genetics, Inc. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society.

Laser biomodulation on stem cells

NASA Astrophysics Data System (ADS)

Liu, Timon C.; Duan, Rui; Li, Yan; Li, Xue-Feng; Tan, Li-Ling; Liu, Songhao

2001-08-01

Stem cells are views from the perspectives of their function, evolution, development, and cause. Counterintuitively, most stem cells may arise late in development, to act principally in tissue renewal, thus ensuring an organisms long-term survival. Surprisingly, recent reports suggest that tissue-specific adult stem cells have the potential to contribute to replenishment of multiple adult tissues. Stem cells are currently in the news for two reasons: the successful cultivation of human embryonic stem cell lines and reports that adult stem cells can differentiate into developmentally unrelated cell types, such as nerve cells into blood cells. The spotlight on stem cells has revealed gaps in our knowledge that must be filled if we are to take advantage of their full potential for treating devastating degenerative diseases such as Parkinsons's disease and muscular dystrophy. We need to know more about the intrinsic controls that keep stem cells as stem cells or direct them along particular differentiation pathways. Such intrinsic regulators are, in turn, sensitive to the influences of the microenvironment, or niche, where stem cells normally reside. Both intrinsic and extrinsic signals regular stem cell fate and some of these signals have now been identified. Vacek et al and Wang et al have studied the effect of low intensity laser on the haemopoietic stem cells in vitro. There experiments show there is indeed the effect of low intensity laser on the haemopoietic stem cells in vitro, and the present effect is the promotion of haemopoietic stem cells proliferation. In other words, low intensity laser irradiation can act as an extrinsic signal regulating stem cell fate. In this paper, we study how low intensity laser can be used to regulate stem cell fate from the viewpoint of collective phototransduction.

Sprouty1 Regulates Reversible Quiescence of a Self-Renewing Adult Muscle Stem Cell Pool during Regeneration

PubMed Central

Shea, Kelly L.; Xiang, Wanyi; LaPorta, Vincent S.; Licht, Jonathan D.; Keller, Charles; Basson, M. Albert; Brack, Andrew S.

2010-01-01

Summary Satellite cells are a heterogeneous population of skeletal muscle specific stem cells capable of self-renewal and differentiation after transplantation. Whether quiescent satellite cells can self-renew and contribute to muscle fiber repair in their endogenous environment in normal regenerating muscle has remained unknown. The transcription factor Pax7 is expressed in satellite cells and is critical for establishing the adult satellite cell pool. Using a temporally-inducible genetic lineage tracing approach (Pax7-CreERtm; R26R-lacZ) to fate-map adult satellite cells, we show that in response to injury quiescent adult Pax7+ cells enter the cell cycle; a subpopulation return to quiescence to fully replenish the satellite cell compartment and the others contribute to de novo muscle fiber formation. We demonstrate that Sprouty1 (Spry1), an inhibitor of receptor tyrosine kinase signaling, is robustly expressed in quiescent Pax7+ satellite cells in uninjured adult muscle, down-regulated in proliferating myogenic cells in injured muscles, and re-induced as Pax7+ cells return to quiescence in regenerated muscles. We show through deletion of Spry1 specifically in cycling adult Pax7+ satellite cells, that Spry1 is required for the return to quiescence and homeostasis of the self-renewing Pax7+ satellite cell pool during repair. Satellite cells unable to return to quiescence succumb to apoptosis leading to a diminished self-renewing Pax7-derived satellite cell pool. Our results define a novel role for Spry1 in adult stem cell biology and tissue repair. PMID:20144785

Astaxanthin and withaferin A block paracrine cytokine interactions between UVB-exposed human keratinocytes and human melanocytes via the attenuation of endothelin-1 secretion and its downstream intracellular signaling.

PubMed

Niwano, Takao; Terazawa, Shuko; Nakajima, Hiroaki; Wakabayashi, Yuki; Imokawa, Genji

2015-06-01

Paracrine interactions between keratinocytes and melanocytes via cytokines play an essential role in regulating pigmentation in epidermal hyperpigmentary disorders. There is an urgent need for a human epidermal model in which melanogenic paracrine interactions between UVB-exposed keratinocytes and melanocytes can be precisely evaluated because human epidermal equivalents consisting of multilayered keratinocytes and melanocytes have significant limitations in this respect. To resolve this challenge, we established a co-culture system with cell inserts using human keratinocytes and human melanocytes that serves as an appropriate new model for UVB-induced hyperpigmentation. Using that new model, we examined the blocking effects of two natural chemicals, astaxanthin and withaferin A, on paracrine cytokine interactions between UVB-exposed keratinocytes and melanocytes and characterized their mechanisms of action. RT-PCR analysis showed that co-culture of human keratinocytes that had been exposed to UVB significantly stimulated human melanocytes to increase their expression of genes encoding microphthalmia-associated transcription factor, tyrosinase and tyrosinase-related protein 1. The catalytic activity of tyrosinase was also increased. ELISA assays revealed that UVB significantly increased the secretion of interleukin-1α, interleukin-6/8, granulocyte macrophage stimulatory factor and endothelin-1 but not α-melanocyte stimulating hormone. The addition of an endothelin-1 neutralizing antibody significantly abrogated the increase of tyrosinase activity. Post-irradiation treatment with astaxanthin or withaferin A significantly abolished the up-regulation of tyrosinase activity induced by UVB. Treatment with astaxanthin or withaferin A significantly reduced the increased levels of interleukin-1α, interleukin-6/8, granulocyte macrophage stimulatory factor and endothelin-1. Withaferin A but not astaxanthin also significantly abrogated the endothelin-1-stimulated activity

Direct Activation of Amidohydrolase Domain-Containing 1 Gene by Thyroid Hormone Implicates a Role in the Formation of Adult Intestinal Stem Cells During Xenopus Metamorphosis

PubMed Central

Okada, Morihiro; Miller, Thomas C.; Fu, Liezhen

2015-01-01

The T3-dependent anuran metamorphosis resembles postembryonic development in mammals, the period around birth when plasma T3 levels peak. In particular, the remodeling of the intestine during metamorphosis mimics neonatal intestinal maturation in mammals when the adult intestinal epithelial self-renewing system is established. We have been using intestinal metamorphosis to investigate how the organ-specific adult stem cells are formed during vertebrate development. Early studies in Xenopus laevis have shown that this process involves complete degeneration of the larval epithelium and de novo formation of adult stem cells. A tissue-specific microarray analysis of intestinal gene expression during Xenopus laevis metamorphosis has identified a number of candidate stem cell genes. Here we have carried out detailed analyses of one such gene, amidohydrolase domain containing 1 (AMDHD1) gene, which encodes an enzyme in the histidine catabolic pathway. We show that AMDHD1 is exclusively expressed in the proliferating adult epithelial stem cells during metamorphosis with little expression in other intestinal tissues. We further provide evidence that T3 activates AMDHD1 gene expression directly at the transcription level through T3 receptor binding to the AMDHD1 gene in the intestine. In addition, we have reported earlier that histidine ammonia-lyase gene, another gene in histidine catabolic pathway, is similarly regulated by T3 in the intestine. These results together suggest that histidine catabolism plays a critical role in the formation and/or proliferation of adult intestinal stem cells during metamorphosis. PMID:26086244

Direct Activation of Amidohydrolase Domain-Containing 1 Gene by Thyroid Hormone Implicates a Role in the Formation of Adult Intestinal Stem Cells During Xenopus Metamorphosis.

PubMed

Okada, Morihiro; Miller, Thomas C; Fu, Liezhen; Shi, Yun-Bo

2015-09-01

The T3-dependent anuran metamorphosis resembles postembryonic development in mammals, the period around birth when plasma T3 levels peak. In particular, the remodeling of the intestine during metamorphosis mimics neonatal intestinal maturation in mammals when the adult intestinal epithelial self-renewing system is established. We have been using intestinal metamorphosis to investigate how the organ-specific adult stem cells are formed during vertebrate development. Early studies in Xenopus laevis have shown that this process involves complete degeneration of the larval epithelium and de novo formation of adult stem cells. A tissue-specific microarray analysis of intestinal gene expression during Xenopus laevis metamorphosis has identified a number of candidate stem cell genes. Here we have carried out detailed analyses of one such gene, amidohydrolase domain containing 1 (AMDHD1) gene, which encodes an enzyme in the histidine catabolic pathway. We show that AMDHD1 is exclusively expressed in the proliferating adult epithelial stem cells during metamorphosis with little expression in other intestinal tissues. We further provide evidence that T3 activates AMDHD1 gene expression directly at the transcription level through T3 receptor binding to the AMDHD1 gene in the intestine. In addition, we have reported earlier that histidine ammonia-lyase gene, another gene in histidine catabolic pathway, is similarly regulated by T3 in the intestine. These results together suggest that histidine catabolism plays a critical role in the formation and/or proliferation of adult intestinal stem cells during metamorphosis.

Isolation of Small SSEA-4-Positive Putative Stem Cells from the Ovarian Surface Epithelium of Adult Human Ovaries by Two Different Methods

PubMed Central

Virant-Klun, Irma; Skutella, Thomas; Hren, Matjaz; Gruden, Kristina; Cvjeticanin, Branko; Vogler, Andrej; Sinkovec, Jasna

2013-01-01

The adult ovarian surface epithelium has already been proposed as a source of stem cells and germinal cells in the literature, therefore it has been termed the “germinal epithelium”. At present more studies have confirmed the presence of stem cells expressing markers of pluripotency in adult mammalian ovaries, including humans. The aim of this study was to isolate a population of stem cells, based on the expression of pluripotency-related stage-specific embryonic antigen-4 (SSEA-4) from adult human ovarian surface epithelium by two different methods: magnetic-activated cell sorting and fluorescence-activated cell sorting. Both methods made it possible to isolate a similar, relatively homogenous population of small, SSEA-4-positive cells with diameters of up to 4 μm from the suspension of cells retrieved by brushing of the ovarian cortex biopsies in reproductive-age and postmenopausal women and in women with premature ovarian failure. The immunocytochemistry and genetic analyses revealed that these small cells—putative stem cells—expressed some primordial germ cell and pluripotency-related markers and might be related to the in vitro development of oocyte-like cells expressing some oocyte-specific transcription factors in the presence of donated follicular fluid with substances important for oocyte growth and development. The stemness of these cells needs to be further researched. PMID:23509763

Constitutive activation of the ERK pathway in melanoma and skin melanocytes in Grey horses.

PubMed

Jiang, Lin; Campagne, Cécile; Sundström, Elisabeth; Sousa, Pedro; Imran, Saima; Seltenhammer, Monika; Pielberg, Gerli; Olsson, Mats J; Egidy, Giorgia; Andersson, Leif; Golovko, Anna

2014-11-21

Constitutive activation of the ERK pathway, occurring in the vast majority of melanocytic neoplasms, has a pivotal role in melanoma development. Different mechanisms underlie this activation in different tumour settings. The Grey phenotype in horses, caused by a 4.6 kb duplication in intron 6 of Syntaxin 17 (STX17), is associated with a very high incidence of cutaneous melanoma, but the molecular mechanism behind the melanomagenesis remains unknown. Here, we investigated the involvement of the ERK pathway in melanoma development in Grey horses. Grey horse melanoma tumours, cell lines and normal skin melanocytes were analyzed with help of indirect immunofluorescence and immunoblotting for the expression of phospho-ERK1/2 in comparison to that in non-grey horse and human counterparts. The mutational status of BRAF, RAS, GNAQ, GNA11 and KIT genes in Grey horse melanomas was determined by direct sequencing. The effect of RAS, RAF and PI3K/AKT pathways on the activation of the ERK signaling in Grey horse melanoma cells was investigated with help of specific inhibitors and immunoblotting. Individual roles of RAF and RAS kinases on the ERK activation were examined using si-RNA based approach and immunoblotting. We found that the ERK pathway is constitutively activated in Grey horse melanoma tumours and cell lines in the absence of somatic activating mutations in BRAF, RAS, GNAQ, GNA11 and KIT genes or alterations in the expression of the main components of the pathway. The pathway is mitogenic and is mediated by BRAF, CRAF and KRAS kinases. Importantly, we found high activation of the ERK pathway also in epidermal melanocytes, suggesting a general predisposition to melanomagenesis in these horses. These findings demonstrate that the presence of the intronic 4.6 kb duplication in STX17 is strongly associated with constitutive activation of the ERK pathway in melanocytic cells in Grey horses in the absence of somatic mutations commonly linked to the activation of this

Adult DRG Stem/Progenitor Cells Generate Pericytes in the Presence of Central Nervous System (CNS) Developmental Cues, and Schwann Cells in Response to CNS Demyelination.

PubMed

Vidal, Marie; Maniglier, Madlyne; Deboux, Cyrille; Bachelin, Corinne; Zujovic, Violetta; Baron-Van Evercooren, Anne

2015-06-01

It has been proposed that the adult dorsal root ganglia (DRG) harbor neural stem/progenitor cells (NPCs) derived from the neural crest. However, the thorough characterization of their stemness and differentiation plasticity was not addressed. In this study, we investigated adult DRG-NPC stem cell properties overtime, and their fate when ectopically grafted in the central nervous system. We compared them in vitro and in vivo to the well-characterized adult spinal cord-NPCs derived from the same donors. Using micro-dissection and neurosphere cultures, we demonstrate that adult DRG-NPCs have quasi unlimited self-expansion capacities without compromising their tissue specific molecular signature. Moreover, they differentiate into multiple peripheral lineages in vitro. After transplantation, adult DRG-NPCs generate pericytes in the developing forebrain but remyelinating Schwann cells in response to spinal cord demyelination. In addition, we show that axonal and endothelial/astrocytic factors as well astrocytes regulate the fate of adult DRG-NPCs in culture. Although the adult DRG-NPC multipotency is restricted to the neural crest lineage, their dual responsiveness to developmental and lesion cues highlights their impressive adaptive and repair potentials making them valuable targets for regenerative medicine. © 2015 AlphaMed Press.

Human Adipose Mesenchymal Cells Inhibit Melanocyte Differentiation and the Pigmentation of Human Skin via Increased Expression of TGF-β1.

PubMed

Klar, Agnes S; Biedermann, Thomas; Michalak, Katarzyna; Michalczyk, Teresa; Meuli-Simmen, Claudia; Scherberich, Arnaud; Meuli, Martin; Reichmann, Ernst

2017-12-01

There is accumulating evidence that interactions between epidermal melanocytes and stromal cells play an important role in the regulation of skin pigmentation. In this study we established a pigmented dermo-epidermal skin model, melDESS, of human origin to investigate the effects of distinct stromal cells on melanogenesis. melDESS is a complex, clinically relevant skin equivalent composed of an epidermis containing both melanocytes and keratinocytes. Its dermal compartment consists either of adipose tissue-derived stromal cells, dermal fibroblasts (Fbs), or a mixture of both cell types. These skin substitutes were transplanted for 5 weeks on the backs of immuno-incompetent rats and analyzed. Gene expression and Western blot analyses showed a significantly higher expression of transforming growth factor-β1 by adipose tissue-derived stromal cells compared with dermal Fbs. In addition, we showed that melanocytes responded to the increased levels of transforming growth factor-β1 by down-regulating the expression of key melanogenic enzymes such as tyrosinase. This caused decreased melanin synthesis and, consequently, greatly reduced pigmentation of melDESS. The conclusions are of utmost clinical relevance, namely that adipose tissue-derived stromal cells derived from the hypodermis fail to appropriately interact with epidermal melanocytes, thus preventing the sustainable restoration of the patient's native skin color in bioengineered skin grafts. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Identification of hair shaft progenitors that create a niche for hair pigmentation

PubMed Central

Liao, Chung-Ping; Booker, Reid C.; Morrison, Sean J.; Le, Lu Q.

2017-01-01

Hair differentiates from follicle stem cells through progenitor cells in the matrix. In contrast to stem cells in the bulge, the identities of the progenitors and the mechanisms by which they regulate hair shaft components are poorly understood. Hair is also pigmented by melanocytes in the follicle. However, the niche that regulates follicular melanocytes is not well characterized. Here, we report the identification of hair shaft progenitors in the matrix that are differentiated from follicular epithelial cells expressing transcription factor KROX20. Depletion of Krox20 lineage cells results in arrest of hair growth, confirming the critical role of KROX20+ cells as antecedents of structural cells found in hair. Expression of stem cell factor (SCF) by these cells is necessary for the maintenance of differentiated melanocytes and for hair pigmentation. Our findings reveal the identities of hair matrix progenitors that regulate hair growth and pigmentation, partly by creating an SCF-dependent niche for follicular melanocytes. PMID:28465357

Adult Mesenchymal Stem Cells: When, Where, and How.

PubMed

Caplan, Arnold I

2015-01-01

Adult mesenchymal stem cells (MSCs) have profound medicinal effects at body sites of tissue injury, disease, or inflammation as either endogenously or exogenously supplied. The medicinal effects are either immunomodulatory or trophic or both. When to deliver these mediators of regeneration, where, and by what delivery apparatus or mechanism will directly determine their medical efficacy. The MSCs help manage the innate regenerative capacity of almost every body tissue and the MSCs have only recently been fully appreciated. Perhaps the most skilled physician-manager of the body's innate regenerative capacity is in orthopedics where the vigorous regeneration and repair capacity of bone through local MSCs-titers is expertly managed by the orthopaedic physician. The challenge is to extend MSCs expertise to address other tissue dysfunctions and diseases. The medicine of tomorrow will encompass optimizing the tissues' intrinsic regenerative potential through management of local MSCs.

New procedure for epidermal cell isolation using kiwi fruit actinidin, and improved culture of melanocytes in the presence of leukaemia inhibitory factor and forskolin.

PubMed

Yarani, Reza; Mansouri, Kamran; Mohammadi-Motlagh, Hamid Reza; Bakhtiari, Mitra; Mostafaie, Ali

2013-06-01

Conventional isolation of epidermis from the dermis and disruption of epidermal sheets to liberate the cells, are performed using proteolytic enzymes such as thermolysin or collagenase. Selective population expansion of melanocytes is achieved by suppressing proliferation of keratinocytes and fibroblasts in epidermal cell suspensions, using phorbol esters and cholera toxin. Here, we introduce a new procedure for isolation of epidermal cells, using proteolytic activity of kiwi fruit actinidin, and also an improved growth medium for melanocytes in the presence of leukaemia inhibitory factor (LIF) and forskolin. Dermo-epidermal separation and epidermal sheet cell dispersion were performed using actinidin compared to conventional proteases including collagenase, thermolysin or trypsin. Thereafter, melanocyte culture was performed in two common media and one modified medium to discover optimization for these cells. We found that dermo-epidermal separation and epidermal sheet cell dispersion using kiwi fruit actinidin were considerably better than previously used methods, both from the aspect of less fibroblast and keratinocyte contamination, and of more viable native cells. Also, melanocytes proliferated better in phorbol ester- and cholera toxin-free proliferation medium supplemented with LIF and forskolin. Less contamination and higher numbers of viable cells were actinidin preferential for separation of epidermis and isolation of epidermal cells. Supplementation of LIF and forskolin to new medium increased proliferation potential of melanocytes in comparison to exogenous mitogens. © 2013 Blackwell Publishing Ltd.

Bone marrow metastasis of malignant melanoma in childhood arising within a congenital melanocytic nevus.

PubMed

Volejnikova, Jana; Bajciova, Viera; Sulovska, Lucie; Geierova, Marie; Buriankova, Eva; Jarosova, Marie; Hajduch, Marian; Sterba, Jaroslav; Mihal, Vladimir

2016-09-01

Malignant melanoma in childhood is infrequent and can arise within congenital melanocytic nevi. Spread of malignant melanoma to the bone marrow, especially in children, is extremely rare. Reported is a case of a 5-year-old boy with a congenital large melanocytic nevus of the head and neck who presented with a short history of low back and leg pain, fever and cervical lymphadenopathy. Despite regular follow-up by a dermatologist and plastic surgeon and repeatedly negative histology of previous partial excisions, diffuse bone marrow infiltration with malignant melanoma was diagnosed. The primary site was identified in the post-excision area. The disease progressed rapidly on ipilimumab immunotherapy and led to death at four months from the diagnosis. Surveillance is indispensable in children with a predisposition to melanoma and nonspecific symptoms such as bone pain, gait impairment or cytopenia, should always be taken into account.

Transcription analysis in the MeLiM swine model identifies RACK1 as a potential marker of malignancy for human melanocytic proliferation

PubMed Central

Egidy, Giorgia; Julé, Sophia; Bossé, Philippe; Bernex, Florence; Geffrotin, Claudine; Vincent-Naulleau, Silvia; Horak, Vratislav; Sastre-Garau, Xavier; Panthier, Jean-Jacques

2008-01-01

Background Metastatic melanoma is a severe disease. Few experimental animal models of metastatic melanoma exist. MeLiM minipigs exhibit spontaneous melanoma. Cutaneous and metastatic lesions are histologically similar to human's. However, most of them eventually spontaneously regress. Our purpose was to investigate whether the MeLiM model could reveal markers of malignancy in human melanocytic proliferations. Results We compared the serial analysis of gene expression (SAGE) between normal pig skin melanocytes and melanoma cells from an early pulmonary metastasis of MeLiM minipigs. Tag identification revealed 55 regulated genes, including GNB2L1 which was found upregulated in the melanoma library. In situ hybridisation confirmed GNB2L1 overexpression in MeLiM melanocytic lesions. GNB2L1 encodes the adaptor protein RACK1, recently shown to influence melanoma cell lines tumorigenicity. We studied the expression of RACK1 by immunofluorescence and confocal microscopy in tissues specimens of normal skin, in cutaneous and metastatic melanoma developped in MeLiM minipigs and in human patients. In pig and human samples, the results were similar. RACK1 protein was not detected in normal epidermal melanocytes. By contrast, RACK1 signal was highly increased in the cytoplasm of all melanocytic cells of superficial spreading melanoma, recurrent dermal lesions and metastatic melanoma. RACK1 partially colocalised with activated PKCαβ. In pig metastases, additional nuclear RACK1 did not associate to BDNF expression. In human nevi, the RACK1 signal was low. Conclusion RACK1 overexpression detected in situ in human melanoma specimens characterized cutaneous and metastatic melanoma raising the possibility that RACK1 can be a potential marker of malignancy in human melanoma. The MeLiM strain provides a relevant model for exploring mechanisms of melanocytic malignant transformation in humans. This study may contribute to a better understanding of melanoma pathophysiology and to

TGF-α equalizes age disparities in stem cell-mediated cardioprotection.

PubMed

Herrmann, Jeremy L; Fiege, Jeremy W; Abarbanell, Aaron M; Weil, Brent R; Wang, Yue; Poynter, Jeffrey A; Manukyan, Mariuxi C; Brewster, Benjamin D; Meldrum, Daniel R

2012-08-01

Neonatal mesenchymal stem cells exhibit less cardioprotective potential than their adult counterparts. Transforming growth factor-α (TGF-α) has been shown to stimulate adult stem cell VEGF production, however, it remains unknown whether it may augment neonatal stem cell paracrine function. We hypothesized that TGF-α would equalize adult and neonatal stem cell paracrine function and cardioprotection during acute ischemia/reperfusion. Bone marrow mesenchymal stem cells isolated from adult and 2.5 wk-old mice were treated with TGF-α (250 ng/mL) for 24 h. VEGF, HGF, IGF-1, IL-1β, and IL-6 production were measure in vitro, and cells were infused via an intracoronary route using a model of isolated heart perfusion. TGF-α equalized adult and neonatal stem cell VEGF production but did not affect production of HGF, IGF-1, IL-1β, or IL-6. ERK, p38 MAPK, and JNK phosphorylation were greater in adult cells in response to TGF-α. Whereas infusion of adult but not neonatal stem cells was associated with improved myocardial functional recovery during reperfusion, infusions of either TGF-α-pretreated cell group were associated with the greatest functional recovery. TGF-α equalizes adult and neonatal mesenchymal stem cell VEGF production and cardioprotection in association with differential regulation of ERK, p38 MAPK, and JNK phosphorylation. Copyright © 2012. Published by Elsevier Inc.

Expression of polysialylated neural cell adhesion molecules on adult stem cells after neuronal differentiation of inner ear spiral ganglion neurons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Kyoung Ho; Yeo, Sang Won, E-mail: swyeo@catholic.ac.kr; Troy, Frederic A., E-mail: fatroy@ucdavis.edu

Highlights: • PolySia expressed on neurons primarily during early stages of neuronal development. • PolySia–NCAM is expressed on neural stem cells from adult guinea pig spiral ganglion. • PolySia is a biomarker that modulates neuronal differentiation in inner ear stem cells. - Abstract: During brain development, polysialylated (polySia) neural cell adhesion molecules (polySia–NCAMs) modulate cell–cell adhesive interactions involved in synaptogenesis, neural plasticity, myelination, and neural stem cell (NSC) proliferation and differentiation. Our findings show that polySia–NCAM is expressed on NSC isolated from adult guinea pig spiral ganglion (GPSG), and in neurons and Schwann cells after differentiation of the NSC withmore » epidermal, glia, fibroblast growth factors (GFs) and neurotrophins. These differentiated cells were immunoreactive with mAb’s to polySia, NCAM, β-III tubulin, nestin, S-100 and stained with BrdU. NSC could regenerate and be differentiated into neurons and Schwann cells. We conclude: (1) polySia is expressed on NSC isolated from adult GPSG and on neurons and Schwann cells differentiated from these NSC; (2) polySia is expressed on neurons primarily during the early stage of neuronal development and is expressed on Schwann cells at points of cell–cell contact; (3) polySia is a functional biomarker that modulates neuronal differentiation in inner ear stem cells. These new findings suggest that replacement of defective cells in the inner ear of hearing impaired patients using adult spiral ganglion neurons may offer potential hope to improve the quality of life for patients with auditory dysfunction and impaired hearing disorders.« less

Regeneration of Murine Hair Follicles is Inhibited by Low-Dose-Rate Gamma Irradiation.

PubMed

Sugaya, Kimihiko; Hirobe, Tomohisa; Ishihara, Yoshie; Inoue, Sonoe

2016-10-01

To determine whether the effects of low-dose-rate gamma (γ) irradiation are identifiable in the regeneration of murine hair follicles, we irradiated whole bodies of C57BL/10JHir mice in the first telogen phase of the hair cycle with 137 Cs γ-rays. The mice were examined for effects on hair follicles, including number, morphology, and pigmentation in the second anagen phase. Effects of γ-radiation on melanocyte stem cells were also investigated by the indirect immunolabeling of tyrosinase-related protein 2 (TRP2). Irradiated skin showed a decrease in hair follicle density and the induction of curved hair follicles along with the presence of white hairs and hypopigmented hair bulbs. There was a small, but not significant, change in the number of TRP2-positive melanocyte stem cells in the hair bulge region of the irradiated skin. These results suggest that low-dose rate γ-irradiation does not deplete melanocyte stem cells, but can damage stem cells and progenitors for both keratinocytes and melanocytes, thereby affecting the structure and pigmentation of regenerated hair follicles in the 2 nd anagen phase.

White spotting phenotype induced by targeted REST disruption during neural crest specification to a melanocyte cell lineage.

PubMed

Aoki, Hitomi; Hara, Akira; Kunisada, Takahiro

2015-05-01

Neural crest cells (NCCs) emerge from the dorsal region of the neural tube of vertebrate embryos and have the pluripotency to differentiate into both neuronal and non-neuronal lineages including melanocytes. Rest, also known as NRSF (neuro-restrictive silencer factor), is a regulator of neuronal development and function and suggested to be involved in the lineage specification of NCCs. However, further investigations of Rest gene functions in vivo have been hampered by the fact that Rest null mice show early embryonic lethality. To investigate the function of Rest in NCC development, we recently established NCC-specific Rest conditional knockout (CKO) mice and observed their neonatal death. Here, we have established viable heterozygous NCC-specific Rest CKO mice to analyze the function of Rest in an NCC-derived melanocyte cell lineage and found that the white spotting phenotype was associated with the reduction in the number of melanoblasts in the embryonic skin. The Rest deletion induced after the specification to melanocytes did not reduce the number of melanoblasts; therefore, the expression of REST during the early neural crest specification stage was necessary for the normal development of melanoblasts to cover all of the skin. © 2015 The Molecular Biology Society of Japan and Wiley Publishing Asia Pty Ltd.

N-acetylcysteine protects melanocytes against oxidative stress/damage and delays onset of UV-induced melanoma in mice

PubMed Central

Cotter, Murray A.; Thomas, Joshua; Cassidy, Pamela; Robinette, Kyle; Jenkins, Noah; Scott, R. Florell; Leachman, Sancy; Samlowski, Wolfram E.; Grossman, Douglas

2008-01-01

UV radiation is the major environmental risk factor for melanoma and a potent inducer of oxidative stress, which is implicated in the pathogenesis of several malignancies. We evaluated whether the thiol antioxidant N-acetylcysteine (NAC) could protect melanocytes from UV-induced oxidative stress/damage in vitro and from UV-induced melanoma in vivo. In melan-a cells, a mouse melanocyte line, NAC (1–10 mM) conferred protection from several UV-induced oxidative sequelae including production of intracellular peroxide, formation of the signature oxidative DNA lesion 8-oxoguanine (8-OG), and depletion of free reduced thiols (primarily glutathione). Mice transgenic for hepatocyte growth factor and Survivin, previously shown to develop melanoma following a single neonatal dose of UV irradiation, were administered NAC (7 mg/ml, mother’s drinking water) transplacentally and through nursing until two weeks after birth. Delivery of NAC in this manner reduced thiol depletion and blocked formation of 8-OG in skin following neonatal UV treatment. Mean onset of UV-induced melanocytic tumors was significantly delayed in NAC-treated compared to control mice (21 vs. 14 weeks, p=0.0003). Our data highlight the potential importance of oxidative stress in the pathogenesis of melanoma, and suggest that NAC may be useful as a chemopreventive agent. PMID:17908992

Characteristics of taurine release in slices from adult and developing mouse brain stem.

PubMed

Saransaari, P; Oja, S S

2006-07-01

Taurine has been thought to function as a regulator of neuronal activity, neuromodulator and osmoregulator. Moreover, it is essential for the development and survival of neural cells and protects them under cell-damaging conditions. Taurine is also involved in many vital functions regulated by the brain stem, including cardiovascular control and arterial blood pressure. The release of taurine has been studied both in vivo and in vitro in higher brain areas, whereas the mechanisms of release have not been systematically characterized in the brain stem. The properties of release of preloaded [(3)H]taurine were now characterized in slices prepared from the mouse brain stem from developing (7-day-old) and young adult (3-month-old) mice, using a superfusion system. In general, taurine release was found to be similar to that in other brain areas, consisting of both Ca(2+)-dependent and Ca(2+)-independent components. Moreover, the release was mediated by Na(+)-, Cl(-)-dependent transporters operating outwards, as both Na(+)-free and Cl(-) -free conditions greatly enhanced it. Cl(-) channel antagonists and a Cl(-) transport inhibitor reduced the release at both ages, indicating that a part of the release occurs through ion channels. Protein kinases appeared not to be involved in taurine release in the brain stem, since substances affecting the activity of protein kinase C or tyrosine kinase had no significant effects. The release was modulated by cAMP second messenger systems and phospholipases at both ages. Furthermore, the metabotropic glutamate receptor agonists likewise suppressed the K(+)-stimulated release at both ages. In the immature brain stem, the ionotropic glutamate receptor agonists N-methyl-D-aspartate (NMDA) and 2-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) potentiated taurine release in a receptor-mediated manner. This could constitute an important mechanism against excitotoxicity, protecting the brain stem under cell-damaging conditions.

How concerns and experiences with medical malpractice affect dermatopathologists' perceptions of their diagnostic practices when interpreting cutaneous melanocytic lesions.

PubMed

Carney, Patricia A; Frederick, Paul D; Reisch, Lisa M; Knezevich, Stevan; Piepkorn, Michael W; Barnhill, Raymond L; Elder, David E; Geller, Berta M; Titus, Linda; Weinstock, Martin A; Nelson, Heidi D; Elmore, Joann G

2016-02-01

We sought to identify characteristics associated with past malpractice lawsuits and how malpractice concerns may affect interpretive practices. We surveyed 207 of 301 (68.8%) eligible dermatopathologists who interpret melanocytic skin lesions in 10 states. The survey assessed dermatopathologists' demographic and clinical practice characteristics, perceptions of how medical malpractice concerns could influence their interpretive practices, and past malpractice lawsuits. Of dermatopathologists, 33% reported past malpractice experiences. Factors associated with being sued included older age (57 vs 48 years, P < .001), lack of board certification or fellowship training in dermatopathology (76.5% vs 53.2%, P = .001), and greater number of years interpreting melanocytic lesions (>20 years: 52.9% vs 20.1%, P < .001). Of participants, 64% reported being moderately or extremely confident in their melanocytic interpretations. Although most dermatopathologists believed that malpractice concerns increased their likelihood of ordering specialized pathology tests, obtaining recuts, and seeking a second opinion, none of these practices were associated with past malpractice. Most dermatopathologists reported concerns about potential harms to patients that may result from their assessments of melanocytic lesions. Limitations of this study include lack of validation of and details about the malpractice suits experienced by participating dermatopathologists. In addition, the study assessed perceptions of practice rather than actual practices that might be associated with malpractice incidents. Most dermatopathologists reported apprehension about how malpractice affects their clinical practice and are concerned about patient safety irrespective of whether they had actually experienced a medical malpractice suit. Copyright © 2015 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

Rhododenol and raspberry ketone impair the normal proliferation of melanocytes through reactive oxygen species-dependent activation of GADD45.

PubMed

Kim, Minjeong; Baek, Heung Soo; Lee, Miri; Park, Hyeonji; Shin, Song Seok; Choi, Dal Woong; Lim, Kyung-Min

2016-04-01

Rhododenol or rhododendrol (RD, 4-(4-hydroxyphenyl)-2-butanol) occurs naturally in many plants along with raspberry ketone (RK, 4-(4-hydroxyphenyl)-2-butanone), a ketone derivative, which include Nikko maple tree (Acer nikoense) and white birch (Betula platyphylla). De-pigmenting activity of RD was discovered and it was used as a brightening ingredient for the skin whitening cosmetics. Recently, cosmetics containing RD were withdrawn from the market because a number of consumers developed leukoderma, inflammation and erythema on their face, neck and hands. Here, we explored the mechanism underlying the toxicity of RD and RK against melanocytes using B16F10 murine melanoma cells and human primary epidermal melanocytes. Treatment with RD or RK resulted in the decreased cell viability in a dose-dependent manner which appeared from cell growth arrest. Consistently, ROS generation was significantly increased by RD or RK as determined by DCF-enhanced fluorescence. An antioxidant enzyme, glutathione peroxidase was depleted as well. In line with ROS generation, oxidative damages and the arrest of normal cell proliferation, GADD genes (Growth Arrest and DNA Damage) that include GADD45 and GADD153, were significantly up-regulated. Prevention of ROS generation with an anti-oxidant, N-acetylcysteine (NAC) significantly rescued RD and RK-suppressed melanocyte proliferation. Consistently, up-regulation of GADD45 and GADD153 was significantly attenuated by NAC, suggesting that increased ROS and the resultant growth arrest of melanocytes may contribute to RD and RK-induced leukoderma. Copyright © 2016 Elsevier Ltd. All rights reserved.

High-dose chemotherapy with autologous hematopoietic stem cell support for solid tumors in adults.

PubMed

Pedrazzoli, Paolo; Rosti, Giovanni; Secondino, Simona; Carminati, Ornella; Demirer, Taner

2007-10-01

Supported by experimental evidence and convincing results of early phase II studies, since the 1980s high-dose chemotherapy (HDC) with autologous hematopoietic stem cell support (AHSCT) has been uncritically adopted by many oncologists as a potentially curative option for several solid tumors. As a result, the number (and size) of randomized trials comparing this approach with conventional chemotherapy initiated (and often abandoned before completion) in this setting was limited and the benefit of a greater escalation of dose of chemotherapy with stem cell transplantation in solid tumors remains, with the possible exception of breast carcinoma (BC) and germ cell tumors (GCT), largely unsettled. In this article, we review and comment on the data from studies to date of HDC for solid tumors in adults.

Epigallocatechin-3-gallate (EGCG) Suppresses the Trafficking of Lymphocytes to Epidermal Melanocytes via Inhibition of JAK2: Its Implication for Vitiligo Treatment.

PubMed

Ning, Weixuan; Wang, Suiquan; Dong, Xiaowu; Liu, Dongyin; Fu, Lifang; Jin, Rong; Xu, Aie

2015-01-01

Vitiligo is an inflammatory skin disorder in which activated T cells play an important role in its onset and progression. Epigallocatechin-3-gallate (EGCG), the major chemical constituent of green tea, exhibits remarkable anti-oxidative and anti-inflammatory properties. EGCG administration has been confirmed to decrease the risk of vitiligo; however, the underlying mechanism is undetermined. In this study, we proved that EGCG directly inhibited the kinase activity of Janus kinase 2 (JAK2). In primary cultured human melanocytes, EGCG pre-treatment attenuated interferon (IFN)-γ-induced phosphorylation of JAK2 and its downstream signal transducer and activator of transcription (STAT)1 and STAT3 in a dose-dependent manner. We further examined the chemoattractant expression in melanocytes and demonstrated that EGCG significantly inhibited IFN-γ-induced expression of intracellular adhesion molecule (ICAM)-1, CXCL10, and monocyte chemotactic protein (MCP)-1 in human melanocytes. In addition, EGCG reduced the protein levels of the corresponding receptors including CD11a, CXCR3, and CCR2 in human T lymphocytes. As a consequence, adhesion of human T cells to melanocytes induced by IFN-γ was effectively suppressed by EGCG. Taken together, our results provided new evidence for the effectiveness of EGCG in vitiligo treatment and supported JAK2 as a molecular target for vitiligo medicine development.

Multipotent adult germ-line stem cells, like other pluripotent stem cells, can be killed by cytotoxic T lymphocytes despite low expression of major histocompatibility complex class I molecules

PubMed Central

Dressel, Ralf; Guan, Kaomei; Nolte, Jessica; Elsner, Leslie; Monecke, Sebastian; Nayernia, Karim; Hasenfuss, Gerd; Engel, Wolfgang

2009-01-01

Background Multipotent adult germ-line stem cells (maGSCs) represent a new pluripotent cell type that can be derived without genetic manipulation from spermatogonial stem cells (SSCs) present in adult testis. Similarly to induced pluripotent stem cells (iPSCs), they could provide a source of cellular grafts for new transplantation therapies of a broad variety of diseases. To test whether these stem cells can be rejected by the recipients, we have analyzed whether maGSCs and iPSCs can become targets for cytotoxic T lymphocytes (CTL) or whether they are protected, as previously proposed for embryonic stem cells (ESCs). Results We have observed that maGSCs can be maintained in prolonged culture with or without leukemia inhibitory factor and/or feeder cells and still retain the capacity to form teratomas in immunodeficient recipients. They were, however, rejected in immunocompetent allogeneic recipients, and the immune response controlled teratoma growth. We analyzed the susceptibility of three maGSC lines to CTL in comparison to ESCs, iPSCs, and F9 teratocarcinoma cells. Major histocompatibility complex (MHC) class I molecules were not detectable by flow cytometry on these stem cell lines, apart from low levels on one maGSC line (maGSC Stra8 SSC5). However, using a quantitative real time PCR analysis H2K and B2m transcripts were detected in all pluripotent stem cell lines. All pluripotent stem cell lines were killed in a peptide-dependent manner by activated CTLs derived from T cell receptor transgenic OT-I mice after pulsing of the targets with the SIINFEKL peptide. Conclusion Pluripotent stem cells, including maGSCs, ESCs, and iPSCs can become targets for CTLs, even if the expression level of MHC class I molecules is below the detection limit of flow cytometry. Thus they are not protected against CTL-mediated cytotoxicity. Therefore, pluripotent cells might be rejected after transplantation by this mechanism if specific antigens are presented and if specific

Stem cells in gastroenterology and hepatology

PubMed Central

Quante, Michael; Wang, Timothy C.

2010-01-01

Cellular and tissue regeneration in the gastrointestinal tract and liver depends on stem cells with properties of longevity, self-renewal and multipotency. Progress in stem cell research and the identification of potential esophageal, gastric, intestinal, colonic, hepatic and pancreatic stem cells provides hope for the use of stem cells in regenerative medicine and treatments for disease. Embryonic stem cells and induced pluripotent stem cells have the potential to give rise to any cell type in the human body, but their therapeutic application remains challenging. The use of adult or tissue-restricted stem cells is emerging as another possible approach for the treatment of gastrointestinal diseases. The same self-renewal properties that allow stem cells to remain immortal and generate any tissue can occasionally make their proliferation difficult to control and make them susceptible to malignant transformation. This Review provides an overview of the different types of stem cell, focusing on tissue-restricted adult stem cells in the fields of gastroenterology and hepatology and summarizing the potential benefits and risks of using stems cells to treat gastroenterological and liver disorders. PMID:19884893

UV-B Radiation Induces Macrophage Migration Inhibitory Factor–Mediated Melanogenesis through Activation of Protease-Activated Receptor-2 and Stem Cell Factor in Keratinocytes

PubMed Central

Enomoto, Akiko; Yoshihisa, Yoko; Yamakoshi, Takako; Ur Rehman, Mati; Norisugi, Osamu; Hara, Hiroshi; Matsunaga, Kenji; Makino, Teruhiko; Nishihira, Jun; Shimizu, Tadamichi

2011-01-01

UV radiation indirectly regulates melanogenesis in melanocytes through a paracrine regulatory mechanism involving keratinocytes. Protease-activated receptor (PAR)-2 activation induces melanosome transfer by increasing phagocytosis of melanosomes by keratinocytes. This study demonstrated that macrophage migration inhibitory factor (MIF) stimulated PAR-2 expression in human keratinocytes. In addition, we showed that MIF stimulated stem cell factor (SCF) release in keratinocytes; however, MIF had no effect on the release of endothelin-1 or prostaglandin E2 in keratinocytes. In addition, MIF had no direct effect on melanin and tyrosinase synthesis in cultured human melanocytes. The effect of MIF on melanogenesis was also examined using a three-dimensional reconstituted human epidermal culture model, which is a novel, commercially available, cultured human epidermis containing functional melanocytes. Migration inhibitory factor induced an increase in melanin content in the epidermis after a 9-day culture period. Moreover, melanin synthesis induced by UV-B stimulation was significantly down-regulated by anti-MIF antibody treatment. An in vivo study showed that the back skin of MIF transgenic mice had a higher melanin content than that of wild-type mice after 12 weeks of UV-B exposure. Therefore, MIF-mediated melanogenesis occurs mainly through the activation of PAR-2 and SCF expression in keratinocytes after exposure to UV-B radiation. PMID:21281800

Lineage tracing of murine adult hematopoietic stem cells reveals active contribution to steady-state hematopoiesis

PubMed Central

Chapple, Richard H.; Tseng, Yu-Jung; Hu, Tianyuan; Kitano, Ayumi; Takeichi, Makiko; Hoegenauer, Kevin A.

2018-01-01

Characterization of hematopoietic stem cells (HSCs) has advanced largely owing to transplantation assays, in which the developmental potential of HSCs is assessed generally in nonhomeostatic conditions. These studies established that adult HSCs extensively contribute to multilineage hematopoietic regeneration upon transplantation. On the contrary, recent studies performing lineage tracing of HSCs under homeostatic conditions have shown that adult HSCs may contribute far less to steady-state hematopoiesis than would be anticipated based on transplantation assays. Here, we used 2 independent HSC-lineage–tracing models to examine the contribution of adult HSCs to steady-state hematopoiesis. We show that adult HSCs contribute robustly to steady-state hematopoiesis, exhibiting faster efflux toward the myeloid lineages compared with lymphoid lineages. Platelets were robustly labeled by HSCs, reaching the same level of labeling as HSCs by 1 year of chase. Our results support the view that adult HSCs contribute to the continuous influx of blood cells during steady-state hematopoiesis. PMID:29848758

Loss of DNA mismatch repair imparts a selective advantage in planarian adult stem cells.

PubMed

Hollenbach, Jessica P; Resch, Alissa M; Palakodeti, Dasaradhi; Graveley, Brenton R; Heinen, Christopher D

2011-01-01

Lynch syndrome (LS) leads to an increased risk of early-onset colorectal and other types of cancer and is caused by germline mutations in DNA mismatch repair (MMR) genes. Loss of MMR function results in a mutator phenotype that likely underlies its role in tumorigenesis. However, loss of MMR also results in the elimination of a DNA damage-induced checkpoint/apoptosis activation barrier that may allow damaged cells to grow unchecked. A fundamental question is whether loss of MMR provides pre-cancerous stem cells an immediate selective advantage in addition to establishing a mutator phenotype. To test this hypothesis in an in vivo system, we utilized the planarian Schmidtea mediterranea which contains a significant population of identifiable adult stem cells. We identified a planarian homolog of human MSH2, a MMR gene which is mutated in 38% of LS cases. The planarian Smed-msh2 is expressed in stem cells and some progeny. We depleted Smed-msh2 mRNA levels by RNA-interference and found a striking survival advantage in these animals treated with a cytotoxic DNA alkylating agent compared to control animals. We demonstrated that this tolerance to DNA damage is due to the survival of mitotically active, MMR-deficient stem cells. Our results suggest that loss of MMR provides an in vivo survival advantage to the stem cell population in the presence of DNA damage that may have implications for tumorigenesis.

Loss of DNA Mismatch Repair Imparts a Selective Advantage in Planarian Adult Stem Cells

PubMed Central

Hollenbach, Jessica P.; Resch, Alissa M.; Palakodeti, Dasaradhi; Graveley, Brenton R.; Heinen, Christopher D.

2011-01-01

Lynch syndrome (LS) leads to an increased risk of early-onset colorectal and other types of cancer and is caused by germline mutations in DNA mismatch repair (MMR) genes. Loss of MMR function results in a mutator phenotype that likely underlies its role in tumorigenesis. However, loss of MMR also results in the elimination of a DNA damage-induced checkpoint/apoptosis activation barrier that may allow damaged cells to grow unchecked. A fundamental question is whether loss of MMR provides pre-cancerous stem cells an immediate selective advantage in addition to establishing a mutator phenotype. To test this hypothesis in an in vivo system, we utilized the planarian Schmidtea mediterranea which contains a significant population of identifiable adult stem cells. We identified a planarian homolog of human MSH2, a MMR gene which is mutated in 38% of LS cases. The planarian Smed-msh2 is expressed in stem cells and some progeny. We depleted Smed-msh2 mRNA levels by RNA-interference and found a striking survival advantage in these animals treated with a cytotoxic DNA alkylating agent compared to control animals. We demonstrated that this tolerance to DNA damage is due to the survival of mitotically active, MMR-deficient stem cells. Our results suggest that loss of MMR provides an in vivo survival advantage to the stem cell population in the presence of DNA damage that may have implications for tumorigenesis. PMID:21747960

Tracing the destiny of mesenchymal stem cells from embryo to adult bone marrow and white adipose tissue via Pdgfrα expression.

PubMed

Miwa, Hiroyuki; Era, Takumi

2018-01-29

Mesenchymal stem cells (MSCs) are somatic stem cells that can be derived from adult bone marrow (BM) and white adipose tissue (WAT), and that display multipotency and self-renewal capacity. Although MSCs are essential for tissue formation and have already been used in clinical therapy, the origins and markers of these cells remain unknown. In this study, we first investigated the developmental process of MSCs in mouse embryos using the gene encoding platelet-derived growth factor receptor α ( Pdgfra ) as a marker. We then traced cells expressing Pdgfra and other genes (brachyury, Sox1 and Pmx1 ) in various mutant mouse embryos until the adult stage. This tracing of MSC origins and destinies indicates that embryonic MSCs emerge in waves and that almost all adult BM MSCs and WAT MSCs originate from mesoderm and embryonic Pdgfrα-positive cells. Furthermore, we demonstrate that adult Pdgfrα-positive cells are involved in some pathological conditions. © 2018. Published by The Company of Biologists Ltd.

Area-Specific Regulation of Quiescent Neural Stem Cells by Notch3 in the Adult Mouse Subependymal Zone.

PubMed

Kawai, Hiroki; Kawaguchi, Daichi; Kuebrich, Benjamin D; Kitamoto, Takeo; Yamaguchi, Masahiro; Gotoh, Yukiko; Furutachi, Shohei

2017-12-06

In the adult mammalian brain, neural stem cells (NSCs) generate new neurons throughout the mammal's lifetime. The balance between quiescence and active cell division among NSCs is crucial in producing appropriate numbers of neurons while maintaining the stem cell pool for a long period. The Notch signaling pathway plays a central role in both maintaining quiescent NSCs (qNSCs) and promoting cell division of active NSCs (aNSCs), although no one knows how this pathway regulates these apparently opposite functions. Notch1 has been shown to promote proliferation of aNSCs without affecting qNSCs in the adult mouse subependymal zone (SEZ). In this study, we found that Notch3 is expressed to a higher extent in qNSCs than in aNSCs while Notch1 is preferentially expressed in aNSCs and transit-amplifying progenitors in the adult mouse SEZ. Furthermore, Notch3 is selectively expressed in the lateral and ventral walls of the SEZ. Knockdown of Notch3 in the lateral wall of the adult SEZ increased the division of NSCs. Moreover, deletion of the Notch3 gene resulted in significant reduction of qNSCs specifically in the lateral and ventral walls, compared with the medial and dorsal walls, of the lateral ventricles. Notch3 deletion also reduced the number of qNSCs activated after antimitotic cytosine β-D-arabinofuranoside (Ara-C) treatment. Importantly, Notch3 deletion preferentially reduced specific subtypes of newborn neurons in the olfactory bulb derived from the lateral walls of the SEZ. These results indicate that Notch isoforms differentially control the quiescent and proliferative steps of adult SEZ NSCs in a domain-specific manner. SIGNIFICANCE STATEMENT In the adult mammalian brain, the subependymal zone (SEZ) of the lateral ventricles is the largest neurogenic niche, where neural stem cells (NSCs) generate neurons. In this study, we found that Notch3 plays an important role in the maintenance of quiescent NSCs (qNSCs), while Notch1 has been reported to act as a regulator

Stem cell marker prominin-1/AC133 is expressed in duct cells of the adult human pancreas.

PubMed

Lardon, Jessy; Corbeil, Denis; Huttner, Wieland B; Ling, Zhidong; Bouwens, Luc

2008-01-01

Many efforts are spent in identifying stem cells in adult pancreas because these could provide a source of beta cells for cell-based therapy of type 1 diabetes. Prominin-1, particularly its specific glycosylation-dependent AC133 epitope, is expressed on stem/progenitor cells of various human tissues and can be used to isolate them. We, therefore, examined its expression in adult human pancreas. To detect prominin-1 protein, monoclonal antibody CD133/1 (AC133 clone), which recognizes the AC133 epitope, and the alphahE2 antiserum, which is directed against the human prominin-1 polypeptide, were used. Prominin-1 RNA expression was analyzed by real-time polymerase chain reaction. We report that all duct-lining cells of the pancreas express prominin-1. Most notably, the cells that react with the alphahE2 antiserum also react with the AC133 antibody. After isolation and culture of human exocrine cells, we found a relative increase in prominin-1 expression both at protein and RNA expression level, which can be explained by an enrichment of cells with ductal phenotype in these cultures. Our data show that pancreatic duct cells express prominin-1 and surprisingly reveal that its particular AC133 epitope is not an exclusive stem and progenitor cell marker.

Information on Stem Cell Research

MedlinePlus

... of stem cells share similar properties there are differences as well. For example, ES cells and iPS cells are able to differentiate into any type of cell, whereas adult stem cells are more restricted in their potential. The promise of all stem cells for use ...

Identification of hair shaft progenitors that create a niche for hair pigmentation.

PubMed

Liao, Chung-Ping; Booker, Reid C; Morrison, Sean J; Le, Lu Q

2017-04-15

Hair differentiates from follicle stem cells through progenitor cells in the matrix. In contrast to stem cells in the bulge, the identities of the progenitors and the mechanisms by which they regulate hair shaft components are poorly understood. Hair is also pigmented by melanocytes in the follicle. However, the niche that regulates follicular melanocytes is not well characterized. Here, we report the identification of hair shaft progenitors in the matrix that are differentiated from follicular epithelial cells expressing transcription factor KROX20. Depletion of Krox20 lineage cells results in arrest of hair growth, confirming the critical role of KROX20 + cells as antecedents of structural cells found in hair. Expression of stem cell factor (SCF) by these cells is necessary for the maintenance of differentiated melanocytes and for hair pigmentation. Our findings reveal the identities of hair matrix progenitors that regulate hair growth and pigmentation, partly by creating an SCF-dependent niche for follicular melanocytes. © 2017 Liao et al.; Published by Cold Spring Harbor Laboratory Press.

Microarray analysis sheds light on the dedifferentiating role of agouti signal protein in murine melanocytes via the Mc1r

PubMed Central

Le Pape, Elodie; Passeron, Thierry; Giubellino, Alessio; Valencia, Julio C.; Wolber, Rainer; Hearing, Vincent J.

2009-01-01

The melanocortin-1 receptor (MC1R) is a key regulator of pigmentation in mammals and is tightly linked to an increased risk of skin cancers, including melanoma, in humans. Physiologically activated by α-melanocyte stimulating hormone (αMSH), MC1R function can be antagonized by a secreted factor, agouti signal protein (ASP), which is responsible for the lighter phenotypes in mammals (including humans), and is also associated with increased risk of skin cancer. It is therefore of great interest to characterize the molecular effects elicited by those MC1R ligands. In this study, we determined the gene expression profiles of murine melan-a melanocytes treated with ASP or αMSH over a 4-day time course using genome-wide oligonucleotide microarrays. As expected, there were significant reductions in expression of numerous melanogenic proteins elicited by ASP, which correlates with its inhibition of pigmentation. ASP also unexpectedly modulated the expression of genes involved in various other cellular pathways, including glutathione synthesis and redox metabolism. Many genes up-regulated by ASP are involved in morphogenesis (especially in nervous system development), cell adhesion, and extracellular matrix-receptor interactions. Concomitantly, ASP enhanced the migratory potential and the invasiveness of melanocytic cells in vitro. These results demonstrate the role of ASP in the dedifferentiation of melanocytes, identify pigment-related genes targeted by ASP and by αMSH, and provide insights into the pleiotropic molecular effects of MC1R signaling that may function during development and may affect skin cancer risk. PMID:19174519

Substance P stimulates endothelin 1 secretion via endothelin-converting enzyme 1 and promotes melanogenesis in human melanocytes.

PubMed

Park, Phil June; Lee, Tae Ryong; Cho, Eun-Gyung

2015-02-01

Substance P (SP) is a well-known neuropeptide implicated in the wound-healing process. The wound occasionally causes a pigmented scar. In the present study, we examined whether increased levels of SP affected melanogenesis. When human melanocytes were treated with SP, the melanin content increased and the pigmentation process accelerated in a dose-dependent manner. In addition to melanogenesis-related genes, the expression of neurokinin 1 receptor, endothelin 1 (EDN1), and EDN receptor type B (EDNRB) also increased at both the messenger RNA and protein levels. Interestingly, secreted EDN1 was observed in the melanocyte culture medium, and this phenomenon was significantly enhanced by SP treatment. Through knockdown experiments using small interfering RNAs (siRNAs), we confirmed that endothelin-converting enzyme 1 (ECE1), EDN1, and EDNRB were involved in SP-induced pigmentation and found that EDN1 secretion was affected by ECE1 and EDN1 siRNAs, but not by EDNRB siRNA. These findings indicate that ECE1 is essential for EDN1 secretion in melanocytes and that EDNRB functions downstream of secreted EDN1 to increase the cAMP levels and activate the melanogenesis-related phosphorylation cascade. This study provides in vitro evidence for a melanogenic function of SP in the skin and suggests that the SP-related signal is a potent target for regulating stress- or wound-induced pigmentation.

The most common mistakes on dermatoscopy of melanocytic lesions

PubMed Central

Kamińska-Winciorek, Grażyna

2015-01-01

Dermatoscopy is a method of in vivo evaluation of the structures within the epidermis and dermis. Currently, it may be the most precise pre-surgical method of diagnosing melanocytic lesions. Diagnostic errors may result in unnecessary removal of benign lesions or what is even worse, they can cause early and very early melanomas to be overlooked. Errors in assessment of dermatoscopy can be divided into those arising from failure to maintain proper test procedures (procedural and technical errors) and knowledge based mistakes related to the lack of sufficient familiarity and experience in dermatoscopy. The article discusses the most common mistakes made by beginner or inexperienced dermatoscopists. PMID:25821425

Histology and ultrastructure of transitional changes in skin morphology in the juvenile and adult four-striped mouse (Rhabdomys pumilio).

PubMed

Stewart, Eranée; Ajao, Moyosore Salihu; Ihunwo, Amadi Ogonda

2013-01-01

The four-striped mouse has a grey to brown coloured coat with four characteristic dark stripes interspersed with three lighter stripes running along its back. The histological differences in the skin of the juvenile and adult mouse were investigated by Haematoxylin and Eosin and Masson Trichrome staining, while melanocytes in the skin were studied through melanin-specific Ferro-ferricyanide staining. The ultrastructure of the juvenile skin, hair follicles, and melanocytes was also explored. In both the juvenile and adult four-striped mouse, pigment-containing cells were observed in the dermis and were homogeneously dispersed throughout this layer. Apart from these cells, the histology of the skin of the adult four-striped mouse was similar to normal mammalian skin. In the juvenile four-striped mouse, abundant hair follicles of varying sizes were observed in the dermis and hypodermis, while hair follicles of similar size were only present in the dermis of adult four-striped mouse. Ultrastructural analysis of juvenile hair follicles revealed that the arrangement and differentiation of cellular layers were typical of a mammal. This study therefore provides unique transition pattern in the four-striped mouse skin morphology different from the textbook description of the normal mammalian skin.

Stem cells in dentistry--part I: stem cell sources.

PubMed

Egusa, Hiroshi; Sonoyama, Wataru; Nishimura, Masahiro; Atsuta, Ikiru; Akiyama, Kentaro

2012-07-01

Stem cells can self-renew and produce different cell types, thus providing new strategies to regenerate missing tissues and treat diseases. In the field of dentistry, adult mesenchymal stem/stromal cells (MSCs) have been identified in several oral and maxillofacial tissues, which suggests that the oral tissues are a rich source of stem cells, and oral stem and mucosal cells are expected to provide an ideal source for genetically reprogrammed cells such as induced pluripotent stem (iPS) cells. Furthermore, oral tissues are expected to be not only a source but also a therapeutic target for stem cells, as stem cell and tissue engineering therapies in dentistry continue to attract increasing clinical interest. Part I of this review outlines various types of intra- and extra-oral tissue-derived stem cells with regard to clinical availability and applications in dentistry. Additionally, appropriate sources of stem cells for regenerative dentistry are discussed with regard to differentiation capacity, accessibility and possible immunomodulatory properties. Copyright © 2012 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Stem cells in the Drosophila digestive system.

PubMed

Zeng, Xiankun; Chauhan, Chhavi; Hou, Steven X

2013-01-01

Adult stem cells maintain tissue homeostasis by continuously replenishing damaged, aged and dead cells in any organism. Five types of region and organ-specific multipotent adult stem cells have been identified in the Drosophila digestive system: intestinal stem cells (ISCs) in the posterior midgut; hindgut intestinal stem cells (HISCs) at the midgut/hindgut junction; renal and nephric stem cells (RNSCs) in the Malpighian Tubules; type I gastric stem cells (GaSCs) at foregut/midgut junction; and type II gastric stem cells (GSSCs) at the middle of the midgut. Despite the fact that each type of stem cell is unique to a particular organ, they share common molecular markers and some regulatory signaling pathways. Due to the simpler tissue structure, ease of performing genetic analysis, and availability of abundant mutants, Drosophila serves as an elegant and powerful model system to study complex stem cell biology. The recent discoveries, particularly in the Drosophila ISC system, have greatly advanced our understanding of stem cell self-renewal, differentiation, and the role of stem cells play in tissue homeostasis/regeneration and adaptive tissue growth.

Generation of Functional Blood Vessels from a Single c-kit+ Adult Vascular Endothelial Stem Cell

PubMed Central

Fang, Shentong; Wei, Jing; Pentinmikko, Nalle; Leinonen, Hannele; Salven, Petri

2012-01-01

In adults, the growth of blood vessels, a process known as angiogenesis, is essential for organ growth and repair. In many disorders including cancer, angiogenesis becomes excessive. The cellular origin of new vascular endothelial cells (ECs) during blood vessel growth in angiogenic situations has remained unknown. Here, we provide evidence for adult vascular endothelial stem cells (VESCs) that reside in the blood vessel wall endothelium. VESCs constitute a small subpopulation within CD117+ (c-kit+) ECs capable of undergoing clonal expansion while other ECs have a very limited proliferative capacity. Isolated VESCs can produce tens of millions of endothelial daughter cells in vitro. A single transplanted c-kit-expressing VESC by the phenotype lin−CD31+CD105+Sca1+CD117+ can generate in vivo functional blood vessels that connect to host circulation. VESCs also have long-term self-renewal capacity, a defining functional property of adult stem cells. To provide functional verification on the role of c-kit in VESCs, we show that a genetic deficit in endothelial c-kit expression markedly decreases total colony-forming VESCs. In vivo, c-kit expression deficit resulted in impaired EC proliferation and angiogenesis and retardation of tumor growth. Isolated VESCs could be used in cell-based therapies for cardiovascular repair to restore tissue vascularization after ischemic events. VESCs also provide a novel cellular target to block pathological angiogenesis and cancer growth. PMID:23091420

Refractometry of melanocyte cell nuclei using optical scatter images recorded by digital Fourier microscopy.

PubMed

Seet, Katrina Y T; Nieminen, Timo A; Zvyagin, Andrei V

2009-01-01

The cell nucleus is the dominant optical scatterer in the cell. Neoplastic cells are characterized by cell nucleus polymorphism and polychromism-i.e., the nuclei exhibits an increase in the distribution of both size and refractive index. The relative size parameter, and its distribution, is proportional to the product of the nucleus size and its relative refractive index and is a useful discriminant between normal and abnormal (cancerous) cells. We demonstrate a recently introduced holographic technique, digital Fourier microscopy (DFM), to provide a sensitive measure of this relative size parameter. Fourier holograms were recorded and optical scatter of individual scatterers were extracted and modeled with Mie theory to determine the relative size parameter. The relative size parameter of individual melanocyte cell nuclei were found to be 16.5+/-0.2, which gives a cell nucleus refractive index of 1.38+/-0.01 and is in good agreement with previously reported data. The relative size parameters of individual malignant melanocyte cell nuclei are expected to be greater than 16.5.

Removing the cells from adult bone marrow derived stem cell therapy does not eliminate cardioprotection.

PubMed

Yasin, Mohammed

2013-04-01

The debate as to whether adult stem cell therapy is regenerative or not continues. The non-regenerative benefits of adult bone marrow-derived stem cell therapy were investigated by testing whether the supernatant derived from unfractionated bone marrow mononuclear cells might be cardioprotective in an animal model of myocardial ischaemia-reperfusion injury. Regional myocardial reperfusion injury was acquired by 25 min reversible left anterior descending coronary artery (LAD) occlusion followed by 2 h reperfusion, in anaesthetized Wistar male rats. Unfractionated bone marrow mononuclear cells (BMMNC) isolated from sibling Wistar male rat whole bone marrow were phenotyped by fluorescence activated cell sorting flowcytometry for the haematopoietic stem cell surface markers c-kit, CD34, CD45 and CD133. Animals subjected to regional myocardial reperfusion injury received either 10 million BMMNC or BMMNC supernatant (BMS); both were collected in 0.5 ml phosphate-buffered saline and delivered by intravenous bolus at the onset of reperfusion. The left ventricular region distal to the LAD occlusion point was excised for measurement of myocardial infarct size and proteomic analysis, which was used to identify whether there were any differences in myocardial proteins associated with intravenous injection of either BMMNC or BMS. BMMNC were phenotyped to be c-kit(+) (7 ± 1%), CD34(+) (7 ± 1%), CD45(+) (54 ± 6%), CD133(+) (15 ± 1%). The supernatant reduced myocardial infarct size (BMS 34 ± 2%, n = 15 vs control 57 ± 2%, n = 7, P < 0.0001), which was comparable to the reduction in infarct size afforded by the injection of cells (BMMNC 33 ± 3% vs control 57 ± 2%, n = 10, P < 0.0001). Proteomics of hearts treated with either BMS or BMMNC demonstrated higher expression of (i) anti-apoptotic signal transduction protein: 14-3-3-epsilon (1.5-fold); (ii) anti-oxidants: peroxiredoxin-6 (2.1-fold); (iii) heat shock proteins: alpha B-crystallin (1.7-fold), heat shock protein 72 (2

Mutation in and lack of expression of tyrosinase-related protein-1 (TRP-1) in melanocytes from an individual with brown oculocutaneous albinism: a new subtype of albinism classified as "OCA3".

PubMed Central

Boissy, R. E.; Zhao, H.; Oetting, W. S.; Austin, L. M.; Wildenberg, S. C.; Boissy, Y. L.; Zhao, Y.; Sturm, R. A.; Hearing, V. J.; King, R. A.; Nordlund, J. J.

1996-01-01

Most types of human oculocutaneous albinism (OCA) result from mutations in the gene for tyrosinase (OCA1) or the P protein (OCA2), although other types of OCA have been described but have not been mapped to specific loci. Melanocytes were cultured from an African-American with OCA, who exhibited the phenotype of Brown OCA, and his normal fraternal twin. Melanocytes cultured from the patient with OCA and the normal twin appeared brown versus black, respectively. Melanocytes from both the patient with OCA and the normal twin demonstrated equal amounts of NP-40-soluble melanin; however, melanocytes from the patient with OCA contained only 7% of the amount of insoluble melanin found from the normal twin. Tyrosinase- related protein-1 (TRP-1) was not detected in the OCA melanocytes by use of various anti-TRP-1 probes. Furthermore, transcripts for TRP-1 were absent in cultured OCA melanocytes. The affected twin was homozygous for a single-bp deletion in exon 6, removing an A in codon 368 and leading to a premature stop at codon 384. Tyrosine hydroxylase activity of the OCA melanocytes was comparable to controls when assayed in cell lysates but was only 30% of controls when assayed in intact cells. We conclude that this mutation of the human TRP-1 gene affects its interaction with tyrosinase, resulting in dysregulation of tyrosinase activity, promotes the synthesis of brown versus black melanin, and is responsible for a third genetic type of OCA in humans, which we classify as "OCA3." Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 PMID:8651291

Running rescues defective adult neurogenesis by shortening the length of the cell cycle of neural stem and progenitor cells.

PubMed

Farioli-Vecchioli, Stefano; Mattera, Andrea; Micheli, Laura; Ceccarelli, Manuela; Leonardi, Luca; Saraulli, Daniele; Costanzi, Marco; Cestari, Vincenzo; Rouault, Jean-Pierre; Tirone, Felice

2014-07-01

Physical exercise increases the generation of new neurons in adult neurogenesis. However, only few studies have investigated the beneficial effects of physical exercise in paradigms of impaired neurogenesis. Here, we demonstrate that running fully reverses the deficient adult neurogenesis within the hippocampus and subventricular zone of the lateral ventricle, observed in mice lacking the antiproliferative gene Btg1. We also evaluated for the first time how running influences the cell cycle kinetics of stem and precursor subpopulations of wild-type and Btg1-null mice, using a new method to determine the cell cycle length. Our data show that in wild-type mice running leads to a cell cycle shortening only of NeuroD1-positive progenitor cells. In contrast, in Btg1-null mice, physical exercise fully reactivates the defective hippocampal neurogenesis, by shortening the S-phase length and the overall cell cycle duration of both neural stem (glial fibrillary acidic protein(+) and Sox2(+)) and progenitor (NeuroD1(+)) cells. These events are sufficient and necessary to reactivate the hyperproliferation observed in Btg1-null early-postnatal mice and to expand the pool of adult neural stem and progenitor cells. Such a sustained increase of cell proliferation in Btg1-null mice after running provides a long-lasting increment of proliferation, differentiation, and production of newborn neurons, which rescues the impaired pattern separation previously identified in Btg1-null mice. This study shows that running positively affects the cell cycle kinetics of specific subpopulations of newly generated neurons and suggests that the plasticity of neural stem cells without cell cycle inhibitory control is reactivated by running, with implications for the long-term modulation of neurogenesis. © 2014 AlphaMed Press.

Towards a "free radical theory of graying": melanocyte apoptosis in the aging human hair follicle is an indicator of oxidative stress induced tissue damage.

PubMed

Arck, Petra Clara; Overall, Rupert; Spatz, Katharina; Liezman, Christiane; Handjiski, Bori; Klapp, Burghard F; Birch-Machin, Mark A; Peters, Eva Milena Johanne

2006-07-01

Oxidative stress is generated by a multitude of environmental and endogenous challenges such as radiation, inflammation, or psychoemotional stress. It also speeds the aging process. Graying is a prominent but little understood feature of aging. Intriguingly, the continuous melanin synthesis in the growing (anagen) hair follicle generates high oxidative stress. We therefore hypothesize that hair bulb melanocytes are especially susceptible to free radical-induced aging. To test this hypothesis, we subjected human scalp skin anagen hair follicles from graying individuals to macroscopic and immunohistomorphometric analysis and organ culture. We found evidence of melanocyte apoptosis and increased oxidative stress in the pigmentary unit of graying hair follicles. The "common" deletion, a marker mitochondrial DNA-deletion for accumulating oxidative stress damage, occurred most prominently in graying hair follicles. Cultured unpigmented hair follicles grew better than pigmented follicles of the same donors. Finally, cultured pigmented hair follicles exposed to exogenous oxidative stress (hydroquinone) showed increased melanocyte apoptosis in the hair bulb. We conclude that oxidative stress is high in hair follicle melanocytes and leads to their selective premature aging and apoptosis. The graying hair follicle, therefore, offers a unique model system to study oxidative stress and aging and to test antiaging therapeutics in their ability to slow down or even stop this process.

Aging and stem cell therapy: AMPK as an applicable pharmacological target for rejuvenation of aged stem cells and achieving higher efficacy in stem cell therapy.

PubMed

Khorraminejad-Shirazi, Mohammadhossein; Farahmandnia, Mohammad; Kardeh, Bahareh; Estedlal, Alireza; Kardeh, Sina; Monabati, Ahmad

2017-10-19

In recent years, tissue regeneration has become a promising field for developing stem cell-based transplantation therapies for human patients. Adult stem cells are affected by the same aging mechanisms that involve somatic cells. One of the mechanisms involved in cellular aging is hyperactivation of mechanistic target of rapamycin complex 1 (mTORC1) and disruption of 5' adenosine monophosphate-activated protein kinase (AMPK). Aging of stem cells results in their impaired regenerative capacity and depletion of stem cell pools in adult tissue, which results in lower efficacy of stem cell therapy. By utilizing an effective therapeutic intervention for aged stem cells, stem cell therapy can become more promising for future application. mTORC1 inhibition is a practical approach to preserve the stem cell pool. In this article, we review the dynamic interaction between sirtuin (silent mating type information regulation 2 homolog) 1, AMPK, and mTORC1. We propose that using AMPK activators such as 5-aminoimidazole-4-carboxamide ribonucleotide, A769662, metformin, and oxidized nicotinamide adenine dinucleotide (NAD + ) are practical ways to be employed for achieving better optimized results in stem cell-based transplantation therapies. Copyright © 2017 King Faisal Specialist Hospital & Research Centre. Published by Elsevier B.V. All rights reserved.

Placenta-an alternative source of stem cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matikainen, Tiina; Laine, Jarmo

2005-09-01

The two most promising practical applications of human stem cells are cellular replacement therapies in human disease and toxicological screening of candidate drug molecules. Both require a source of human stem cells that can be isolated, purified, expanded in number and differentiated into the cell type of choice in a controlled manner. Currently, uses of both embryonic and adult stem cells are investigated. While embryonic stem cells are pluripotent and can differentiate into any specialised cell type, their use requires establishment of embryonic stem cell lines using the inner cell mass of an early pre-implantation embryo. As the blastocyst ismore » destroyed during the process, ethical issues need to be carefully considered. The use of embryonic stem cells is also limited by the difficulties in growing large numbers of the cells without inducing spontaneous differentiation, and the problems in controlling directed differentiation of the cells. The use of adult stem cells, typically derived from bone marrow, but also from other tissues, is ethically non-controversial but their differentiation potential is more limited than that of the embryonic stem cells. Since human cord blood, umbilical cord, placenta and amnion are normally discarded at birth, they provide an easily accessible alternative source of stem cells. We review the potential and current status of the use of adult stem cells derived from the placenta or umbilical cord in therapeutic and toxicological applications.« less

Neural Stem Cells and Its Derivatives as a New Material for Melanin Inhibition

PubMed Central

Hwang, Insik

2017-01-01

The pigment molecule, melanin, is produced from melanosomes of melanocytes through melanogenesis, which is a complex process involving a combination of chemical and enzymatically catalyzed reactions. The synthesis of melanin is primarily influenced by tyrosinase (TYR), which has attracted interest as a target molecule for the regulation of pigmentation or depigmentation in skin. Thus, direct inhibitors of TYR activity have been sought from various natural and synthetic materials. However, due to issues with these inhibitors, such as weak or permanent ability for depigmentation, allergy, irritant dermatitis and rapid oxidation, in vitro and in vivo, the development of new materials that inhibit melanin production is essential. A conditioned medium (CM) derived from stem cells contains many cell-secreted factors, such as cytokines, chemokines, growth factors and extracellular vesicles including exosomes. In addition, the secreted factors could negatively regulate melanin production through stimulation of a microenvironment of skin tissue in a paracrine manner, which allows the neural stem cell CM to be explored as a new material for skin depigmentation. In this review, we will summarize the current knowledge regulating depigmentation, and discuss the potential of neural stem cells and their derivatives, as a new material for skin depigmentation. PMID:29271951

Adult bone marrow-derived stem cells for the lung: implications for pediatric lung diseases.

PubMed

van Haaften, Timothy; Thébaud, Bernard

2006-04-01

Bronchopulmonary dysplasia (BPD) and cystic fibrosis (CF) are two common serious chronic respiratory disorders without specific treatments affecting children. BPD is characterized by an arrest in alveolar growth in premature infants requiring respiratory support. CF is the most common fatal inherited genetic disorder characterized by abnormally thick mucus secretions, recurrent infection and ultimately lung destruction. One commonality between these two diseases is the promise of utilizing stem cells therapeutically. Indeed, the use of exogenous cells to supplement the natural repair mechanisms or the possibility of genetic manipulation in vitro before administration are appealing therapeutic options for these diseases. Increasing attention has been focused on the use of adult bone marrow-derived stem cells (BMSC) to regenerate damaged organs such as the heart, the brain, and the liver. However, due to the lung's complexity as well as the low rate of cellular turnover within the lung, progress has been slower in this area compared with the skin or liver. Initial work suggests that BMSC can engraft and differentiate into a variety of lung cells, but these findings have been challenged recently. This article critically reviews the current advances on the therapeutic use of stem cells for lung regeneration.

Expression of the Argonaute protein PiwiL2 and piRNAs in adult mouse mesenchymal stem cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Qiuling; Ma, Qi; Shehadeh, Lina A.

Piwi (P-element-induced wimpy testis) first discovered in Drosophila is a member of the Argonaute family of micro-RNA binding proteins with essential roles in germ-cell development. The murine homologue of PiwiL2, also known as Mili is selectively expressed in the testes, and mice bearing targeted mutations of the PiwiL2 gene are male-sterile. PiwiL2 proteins are thought to protect the germ line genome by suppressing retrotransposons, stabilizing heterochromatin structure, and regulating target genes during meiosis and mitosis. Here, we report that PiwiL2 and associated piRNAs (piRs) may play similar roles in adult mouse mesenchymal stem cells. We found that PiwiL2 is expressedmore » in the cytoplasm of metaphase mesenchymal stem cells from the bone marrow of adult and aged mice. Knockdown of PiwiL2 with a specific siRNA enhanced cell proliferation, significantly increased the number of cells in G1/S and G2/M cell cycle phases and was associated with increased expression of cell cycle genes CCND1, CDK8, microtubule regulation genes, and decreased expression of tumor suppressors Cables 1, LATS, and Cxxc4. The results suggest broader roles for Piwi in genome surveillance beyond the germ line and a possible role in regulating the cell cycle of mesenchymal stem cells.« less

A dual role of p21 in stem cell aging.

PubMed

Ju, Zhenyu; Choudhury, Aaheli Roy; Rudolph, K Lenhard

2007-04-01

A decline in adult stem cell function occurs during aging, likely contributing to the decline in organ homeostasis and regeneration with age. An emerging field in aging research is to analyze molecular pathways limiting adult stem cell function in response to macromolecular damage accumulation during aging. Current data suggest that the p21 cell cycle inhibitor has a dual role in stem cell aging: On one hand, p21 protects adult stem cells from acute genotoxic stress by preventing inappropriate cycling of acutely damaged stem cells. On the other hand, p21 activation impairs stem cell function and survival of aging telomere dysfunctional mice indicating that p21 checkpoint function is disadvantageous in the context of chronic and persistent damage, which accumulates during aging. This article focuses on these dual roles of p21 in aging stem cells.

Differentiated cells are more efficient than adult stem cells for cloning by somatic cell nuclear transfer.

PubMed

Sung, Li-Ying; Gao, Shaorong; Shen, Hongmei; Yu, Hui; Song, Yifang; Smith, Sadie L; Chang, Ching-Chien; Inoue, Kimiko; Kuo, Lynn; Lian, Jin; Li, Ao; Tian, X Cindy; Tuck, David P; Weissman, Sherman M; Yang, Xiangzhong; Cheng, Tao

2006-11-01

Since the creation of Dolly via somatic cell nuclear transfer (SCNT), more than a dozen species of mammals have been cloned using this technology. One hypothesis for the limited success of cloning via SCNT (1%-5%) is that the clones are likely to be derived from adult stem cells. Support for this hypothesis comes from the findings that the reproductive cloning efficiency for embryonic stem cells is five to ten times higher than that for somatic cells as donors and that cloned pups cannot be produced directly from cloned embryos derived from differentiated B and T cells or neuronal cells. The question remains as to whether SCNT-derived animal clones can be derived from truly differentiated somatic cells. We tested this hypothesis with mouse hematopoietic cells at different differentiation stages: hematopoietic stem cells, progenitor cells and granulocytes. We found that cloning efficiency increases over the differentiation hierarchy, and terminally differentiated postmitotic granulocytes yield cloned pups with the greatest cloning efficiency.

Evolution of Energy Metabolism, Stem Cells and Cancer Stem Cells: How the Warburg and Barker Hypotheses Might Be Linked