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1.
Chemosphere ; 235: 713-718, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31279121

RESUMO

Chemical leukoderma is a patchy hypopigmentation in the skin. Phenol derivatives such as raspberry ketone have been reported to cause the development of occupationally induced leukoderma. Recently, 2% (w/w) rhododenol, a reduced form of raspberry ketone used in a skin-lightning agent, also caused the development of leukoderma in >16,000 users, about 2% of all users, in Asian countries including Japan. However, a method for assessing the risk of leukoderma caused by 2% rhododenol has not been established despite the fact that the development of leukoderma caused by 30% rhododenol was previously shown in animal experiments. Establishment of a novel technique for risk assessment of leukoderma in humans caused by external treatment with chemicals is needed to prevent a possible future chemical disaster. This study demonstrated that external treatment with 2% rhododenol and the same concentration of raspberry ketone caused the development of leukoderma in murine tail skin without exception with significant decreases in the amount of melanin and number of melanocytes in the epidermis. Thus, a novel in vivo technique that can assess the risk of leukoderma caused by 2% rhododenol was developed. The unique technique using tail skin has the potential to prevent chemical leukoderma in the future.

2.
Chemosphere ; 229: 611-617, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31102916

RESUMO

Since tannery workers in developing countries are chronically exposed to high levels of chromium (Cr), there are serious concerns about health problems. However, there has been limited study in which Cr levels were measured in tannery workers, who are chronically exposed to Cr. Our preliminary inspection showed that there was hyperpigmented skin in tannery workers. We therefore investigated the correlation between skin pigmentation levels digitally evaluated as L* values by using a reflectance spectrophotometer and Cr levels in skin appendages in 100 male tannery workers and in 49 male non-tannery workers in Bangladesh. Digitalized skin pigmentation levels of the face and feet in addition to Cr levels in hair and toenails in tannery workers were significantly higher than those in non-tannery workers in our univariate analysis. Spearman's rank correlation coefficient analysis showed significant correlation between duration of tannery work (years) and Cr levels in hair (r = 0.62) and toenails (r = 0.61). Our multivariate analysis also showed that Cr levels in hair and toenails were significantly correlated with digitalized skin pigmentation levels of the face and feet in addition to duration of tannery work in all participants. Thus, our results showed the development of hyperpigmented skin in tannery workers. Our results also suggested that hyperpigmented skin could be a useful diagnostic marker for chronic exposure to Cr. Furthermore, cutaneous L* value might be a convenient marker for detection of chronic Cr poisoning, since the digitalized values enable objective evaluation of skin pigmented levels by general people as well as dermatologists.


Assuntos
Cromo/análise , Hiperpigmentação/induzido quimicamente , Doenças Profissionais/induzido quimicamente , Exposição Ocupacional/efeitos adversos , Adulto , Idoso , Bangladesh , Cromo/toxicidade , Face , , Cabelo/química , Humanos , Hiperpigmentação/patologia , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Unhas/química , Pele/química , Espectrofotometria/métodos , Curtume
3.
Environ Health Prev Med ; 24(1): 36, 2019 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-31101002

RESUMO

BACKGROUND: Melanin is detectable in various sense organs including the skin in animals. It has been reported that melanin adsorbs toxic elements such as mercury, cadmium, and lead. In this study, we investigated the adsorption of molybdenum, which is widely recognized as a toxic element, by melanin. METHODS: Molybdenum level of the mouse skin was measured by inductively coupled plasma mass spectrometry. The pigmentation level of murine skin was digitalized as the L* value by using a reflectance spectrophotometer. An in vitro adsorption assay was performed to confirm the interaction between molybdenum and melanin. RESULTS: Our analysis of hairless mice with different levels of skin pigmentation showed that the level of molybdenum increased with an increase in the level of skin pigmentation (L* value). Moreover, our analysis by Spearman's correlation coefficient test showed a strong correlation (r = - 0.9441, p < 0.0001) between L* value and molybdenum level. Our cell-free experiment using the Langmuir isotherm provided evidence for the adsorption of molybdenum by melanin. The maximum adsorption capacity of 1 mg of synthetic melanin for molybdenum was 131 µg in theory. CONCLUSION: Our in vivo and in vitro results showed a new aspect of melanin as an adsorbent of molybdenum.


Assuntos
Melaninas/química , Molibdênio/química , Poluentes Químicos da Água/química , Adsorção , Animais , Melaninas/metabolismo , Camundongos , Camundongos Pelados , Camundongos Transgênicos , Molibdênio/metabolismo , Molibdênio/farmacologia , Pele/química , Pele/efeitos dos fármacos , Pigmentação da Pele/efeitos dos fármacos , Poluentes Químicos da Água/metabolismo , Poluentes Químicos da Água/farmacologia
4.
Sci Rep ; 8(1): 16894, 2018 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-30442994

RESUMO

About 80% of young people use personal listening devices (PLDs) including MP3 players to listen to music, which consists of sound components with various frequencies. Previous studies showed that exposure to noise of high intensities affected balance in humans. However, there is no information about a frequency-dependent effect of sound components in music from a PLD on balance in young people. In this study, we determined the associations between sound component levels (dB) at 100, 1000 and 4000 Hz in music from a portable listening device (PLD) and balance objectively determined by posturography in young adults (n = 110). We divided the subjects into two groups (low and high exposure groups) based on cut-off values of sound component levels at each frequency using receiver operating characteristic (ROC) curves. Balance in the high exposure group (≥46.6 dB) at 100 Hz was significantly better than that in low exposure group in logistic regression models adjusted for sex, BMI, smoking status and alcohol intake, while there were no significant associations at 1000 and 4000 Hz. Thus, this study demonstrated for the first time that the sound component at 100 Hz with more than 46.6 dB in music improved balance in young adults.

5.
Chemosphere ; 210: 384-391, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30015129

RESUMO

At present, beneficial effects of melanin and harmful effects of barium have been reported. However, little is known about the adsorption of barium, and even less is known about the biological significance of adsorption of barium by melanin. In this study, we showed that there was a strong correlation between the digitalized level of skin pigmentation and barium level in murine skin compared to the correlations between skin pigmentation level and levels of homologous elements of barium (magnesium, calcium and strontium). The concentration of subcutaneously injected barium in skin with a high level of pigmentation was higher than that in skin with a low level of pigmentation. Our cell-free experiment using the Langmuir isotherm for adsorption of barium in synthetic melanin also provided direct evidence of adsorption of barium by melanin. We then investigated the biological significance of melanin-mediated barium adsorption. We found barium-mediated increase in transforming activity in pigmented melanocytes (melan-a) but not in unpigmented melanocytes (melan-c) after confirming that the barium level in melan-a melanocytes was 3.4-fold higher than that in melan-c melanocytes after culture of 5 µM barium for 24 h. Taken together, our results not only indicate adsorption of barium by melanin in mice, cells and cell-free systems but also suggest a disadvantageous effect of adsorption of barium by melanin on transforming activity in cultured cells.


Assuntos
Bário/metabolismo , Melaninas/metabolismo , Pigmentação/efeitos dos fármacos , Adsorção , Animais , Bário/farmacologia , Sistema Livre de Células , Células Cultivadas , Humanos , Melanócitos/metabolismo , Camundongos
6.
Dev Biol ; 433(2): 262-275, 2018 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-29198566

RESUMO

Axolotls can regenerate complex structures through recruitment and remodeling of cells within mature tissues. Accessing the underlying mechanisms at a molecular resolution is crucial to understand how injury triggers regeneration and how it proceeds. However, gene transformation in adult tissues can be challenging. Here we characterize the use of pseudotyped baculovirus (BV) as an effective gene transfer method both for cells within mature limb tissue and within the blastema. These cells remain competent to participate in regeneration after transduction. We further characterize the effectiveness of BV for gene overexpression studies by overexpressing Shh in the blastema, which yields a high penetrance of classic polydactyly phenotypes. Overall, our work establishes BV as a powerful tool to access gene function in axolotl limb regeneration.


Assuntos
Ambystoma mexicanum/fisiologia , Membro Anterior/fisiologia , Regulação da Expressão Gênica , Vetores Genéticos/genética , Nucleopolyhedrovirus/genética , Regeneração/fisiologia , Transdução Genética , Ambystoma mexicanum/genética , Amputação , Animais , Perfilação da Expressão Gênica , Genes Reporter , Genes Sintéticos , Proteínas Hedgehog/genética , Proteínas Hedgehog/fisiologia , Proteínas de Homeodomínio/fisiologia , Humanos , Glicoproteínas de Membrana/fisiologia , Mesoderma/citologia , Proteínas Recombinantes/metabolismo , Regeneração/genética , Transgenes , Proteínas do Envelope Viral/fisiologia , Cicatrização/genética , Cicatrização/fisiologia
7.
Dev Biol ; 432(1): 63-71, 2017 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-29030146

RESUMO

Repairing injured tissues / organs is one of the major challenges for the maintenance of proper organ function in adulthood. In mammals, the central nervous system including the spinal cord, once established during embryonic development, has very limited capacity to regenerate. In contrast, salamanders such as axolotls can fully regenerate the injured spinal cord, making this a very powerful vertebrate model system for studying this process. Here we discuss the cellular and molecular requirements for spinal cord regeneration in the axolotl. The recent development of tools to test molecular function, including CRISPR-mediated gene editing, has lead to the identification of key players involved in the cell response to injury that ultimately leads to outgrowth of neural stem cells that are competent to replay the process of spinal cord development to replace the damaged/missing tissue.


Assuntos
Ambystoma mexicanum/fisiologia , Regeneração da Medula Espinal/fisiologia , Animais , Proliferação de Células/fisiologia , Células-Tronco Neurais/fisiologia , Traumatismos da Medula Espinal/fisiopatologia
8.
Dev Cell ; 40(6): 608-617.e6, 2017 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-28350991

RESUMO

Limb amputation in the newt induces myofibers to dedifferentiate and re-enter the cell cycle to generate proliferative myogenic precursors in the regeneration blastema. Here we show that bone morphogenetic proteins (BMPs) and mature BMPs that have been further cleaved by serum proteases induce cell cycle entry by dedifferentiating newt muscle cells. Protease-activated BMP4/7 heterodimers that are present in serum strongly induced myotube cell cycle re-entry with protease cleavage yielding a 30-fold potency increase of BMP4/7 compared with canonical BMP4/7. Inhibition of BMP signaling via muscle-specific dominant-negative receptor expression reduced cell cycle entry in vitro and in vivo. In vivo inhibition of serine protease activity depressed cell cycle re-entry, which in turn was rescued by cleaved-mimic BMP. This work identifies a mechanism of BMP activation that generates blastema cells from differentiated muscle.


Assuntos
Proteínas Morfogenéticas Ósseas/farmacologia , Ciclo Celular/efeitos dos fármacos , Desdiferenciação Celular/efeitos dos fármacos , Extremidades/fisiologia , Células Musculares/citologia , Peptídeo Hidrolases/farmacologia , Regeneração/efeitos dos fármacos , Salamandridae/fisiologia , Animais , Bovinos , Fibrinolisina/farmacologia , Células HEK293 , Humanos , Células Musculares/efeitos dos fármacos , Fibras Musculares Esqueléticas/efeitos dos fármacos , Fibras Musculares Esqueléticas/metabolismo , Multimerização Proteica/efeitos dos fármacos , Receptores de Superfície Celular/metabolismo , Proteínas Recombinantes/farmacologia , Fase S/efeitos dos fármacos , Soro/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteínas Smad/metabolismo , Trombina/farmacologia
9.
Dev Biol ; 422(2): 155-170, 2017 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-28017643

RESUMO

Classical grafting experiments in the Mexican axolotl had shown that the posterior neural plate of the neurula is no specified neuroectoderm but gives rise to somites of the tail and posterior trunk. The bipotentiality of this region with neuromesodermal progenitor cell populations was revealed more recently also in zebrafish, chick, and mouse. We reinvestigated the potency of the posterior plate in axolotl using grafts from transgenic embryos, immunohistochemistry, and in situ hybridization. The posterior plate is brachyury-positive except for its more anterior parts which express sox2. Between anterior and posterior regions of the posterior plate a small domain with sox2+ and bra+ cells exists. Lineage analysis of grafted GFP-labeled posterior plate tissue revealed that posterior GFP+ cells move from dorsal to ventral, form the posterior wall, turn anterior bilaterally, and join the gastrulated paraxial presomitic mesoderm. More anterior sox2+/GFP+ cells, however, are integrated into the developing spinal cord. Tail notochord is formed from axial mesoderm involuted already during gastrulation. Thus the posterior neural plate is a postgastrula source of paraxial mesoderm, which performs an anterior turn, a novel morphogenetic movement. More anterior plate cells, in contrast, do not turn anteriorly but become specified to form tail spinal cord.


Assuntos
Ambystoma mexicanum/embriologia , Mesoderma/embriologia , Placa Neural/embriologia , Tubo Neural/embriologia , Medula Espinal/embriologia , Cauda/embriologia , Animais , Animais Geneticamente Modificados , Células Cultivadas , Proteínas Fetais/metabolismo , Gastrulação/fisiologia , Proteínas de Fluorescência Verde/genética , Notocorda/embriologia , Fatores de Transcrição SOXB1/biossíntese , Somitos/embriologia , Células-Tronco/citologia , Proteínas com Domínio T/metabolismo
10.
Elife ; 4: e10230, 2015 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-26568310

RESUMO

Axolotls are uniquely able to mobilize neural stem cells to regenerate all missing regions of the spinal cord. How a neural stem cell under homeostasis converts after injury to a highly regenerative cell remains unknown. Here, we show that during regeneration, axolotl neural stem cells repress neurogenic genes and reactivate a transcriptional program similar to embryonic neuroepithelial cells. This dedifferentiation includes the acquisition of rapid cell cycles, the switch from neurogenic to proliferative divisions, and the re-expression of planar cell polarity (PCP) pathway components. We show that PCP induction is essential to reorient mitotic spindles along the anterior-posterior axis of elongation, and orthogonal to the cell apical-basal axis. Disruption of this property results in premature neurogenesis and halts regeneration. Our findings reveal a key role for PCP in coordinating the morphogenesis of spinal cord outgrowth with the switch from a homeostatic to a regenerative stem cell that restores missing tissue.


Assuntos
Ambystoma mexicanum , Proliferação de Células , Células-Tronco Neurais/fisiologia , Regeneração da Medula Espinal , Animais , Polaridade Celular
11.
Sci Rep ; 5: 11428, 2015 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-26086331

RESUMO

Mesenchyme is an embryonic precursor tissue that generates a range of structures in vertebrates including cartilage, bone, muscle, kidney, and the erythropoietic system. Mesenchyme originates from both mesoderm and the neural crest, an ectodermal cell population, via an epithelial to mesenchymal transition (EMT). Because ectodermal and mesodermal mesenchyme can form in close proximity and give rise to similar derivatives, the embryonic origin of many mesenchyme-derived tissues is still unclear. Recent work using genetic lineage tracing methods have upended classical ideas about the contributions of mesodermal mesenchyme and neural crest to particular structures. Using similar strategies in the Mexican axolotl (Ambystoma mexicanum), and the South African clawed toad (Xenopus laevis), we traced the origins of fin mesenchyme and tail muscle in amphibians. Here we present evidence that fin mesenchyme and striated tail muscle in both animals are derived solely from mesoderm and not from neural crest. In the context of recent work in zebrafish, our experiments suggest that trunk neural crest cells in the last common ancestor of tetrapods and ray-finned fish lacked the ability to form ectomesenchyme and its derivatives.


Assuntos
Anfíbios/embriologia , Mesoderma/embriologia , Anfíbios/metabolismo , Animais , Biomarcadores , Epiderme/embriologia , Epiderme/metabolismo , Larva , Mesoderma/metabolismo , Músculos/embriologia , Crista Neural/embriologia , Crista Neural/metabolismo , Cauda/embriologia
12.
Stem Cell Reports ; 3(6): 987-99, 2014 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-25454634

RESUMO

Inducing organogenesis in 3D culture is an important aspect of stem cell research. Anterior neural structures have been produced from large embryonic stem cell (ESC) aggregates, but the steps involved in patterning such complex structures have been ill defined, as embryoid bodies typically contained many cell types. Here we show that single mouse ESCs directly embedded in Matrigel or defined synthetic matrices under neural induction conditions can clonally form neuroepithelial cysts containing a single lumen in 3D. Untreated cysts were uniformly dorsal and could be ventralized to floor plate (FP). Retinoic acid posteriorized cysts to cervical levels and induced localize FP formation yielding full patterning along the dorsal/ventral (DV) axis. Correct spatial organization of motor neurons, interneurons, and dorsal interneurons along the DV axis was observed. This system serves as a valuable tool for studying morphogen action in 3D and as a source of patterned spinal cord tissue.


Assuntos
Células-Tronco Embrionárias/citologia , Tubo Neural/citologia , Tubo Neural/fisiologia , Organogênese , Animais , Biomarcadores , Padronização Corporal/efeitos dos fármacos , Padronização Corporal/genética , Diferenciação Celular/efeitos dos fármacos , Desenvolvimento Embrionário/efeitos dos fármacos , Desenvolvimento Embrionário/genética , Células-Tronco Embrionárias/efeitos dos fármacos , Células-Tronco Embrionárias/metabolismo , Expressão Gênica , Proteínas Hedgehog/genética , Camundongos , Organogênese/efeitos dos fármacos , Organogênese/genética , Técnicas de Cultura de Tecidos , Tretinoína/farmacologia
13.
Stem Cell Reports ; 3(3): 444-59, 2014 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-25241743

RESUMO

The salamander is the only tetrapod that functionally regenerates all cell types of the limb and spinal cord (SC) and thus represents an important regeneration model, but the lack of gene-knockout technology has limited molecular analysis. We compared transcriptional activator-like effector nucleases (TALENs) and clustered regularly interspaced short palindromic repeats (CRISPRs) in the knockout of three loci in the axolotl and find that CRISPRs show highly penetrant knockout with less toxic effects compared to TALENs. Deletion of Sox2 in up to 100% of cells yielded viable F0 larvae with normal SC organization and ependymoglial cell marker expression such as GFAP and ZO-1. However, upon tail amputation, neural stem cell proliferation was inhibited, resulting in spinal-cord-specific regeneration failure. In contrast, the mesodermal blastema formed normally. Sox3 expression during development, but not regeneration, most likely allowed embryonic survival and the regeneration-specific phenotype. This analysis represents the first tissue-specific regeneration phenotype from the genomic deletion of a gene in the axolotl.


Assuntos
Ambystoma mexicanum/fisiologia , Proteínas de Anfíbios/genética , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Deleção de Genes , Células-Tronco Neurais/citologia , Regeneração , Fatores de Transcrição SOXB1/genética , Ambystoma mexicanum/embriologia , Ambystoma mexicanum/genética , Animais , Sequência de Bases , Proliferação de Células , Regulação da Expressão Gênica no Desenvolvimento , Técnicas de Inativação de Genes , Dados de Sequência Molecular , Regeneração da Medula Espinal
14.
Cell Stem Cell ; 14(2): 174-87, 2014 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-24268695

RESUMO

Salamanders regenerate appendages via a progenitor pool called the blastema. The cellular mechanisms underlying regeneration of muscle have been much debated but have remained unclear. Here we applied Cre-loxP genetic fate mapping to skeletal muscle during limb regeneration in two salamander species, Notophthalmus viridescens (newt) and Ambystoma mexicanum (axolotl). Remarkably, we found that myofiber dedifferentiation is an integral part of limb regeneration in the newt, but not in axolotl. In the newt, myofiber fragmentation results in proliferating, PAX7(-) mononuclear cells in the blastema that give rise to the skeletal muscle in the new limb. In contrast, myofibers in axolotl do not generate proliferating cells, and do not contribute to newly regenerated muscle; instead, resident PAX7(+) cells provide the regeneration activity. Our results therefore show significant diversity in limb muscle regeneration mechanisms among salamanders and suggest that multiple strategies may be feasible for inducing regeneration in other species, including mammals.


Assuntos
Ambystoma mexicanum/fisiologia , Desdiferenciação Celular , Músculo Esquelético/citologia , Músculo Esquelético/fisiologia , Regeneração/fisiologia , Salamandridae/fisiologia , Células-Tronco/citologia , Animais , Animais Geneticamente Modificados , Proliferação de Células , Extremidades/fisiologia , Genes Reporter , Células Germinativas/citologia , Células Germinativas/metabolismo , Larva/fisiologia , Mesoderma/citologia , Mesoderma/transplante , Fibras Musculares Esqueléticas/citologia , Fibras Musculares Esqueléticas/fisiologia , Fator de Transcrição PAX7/metabolismo
15.
Science ; 342(6164): 1375-9, 2013 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-24337297

RESUMO

An amputated salamander limb regenerates the correct number of segments. Models explaining limb regeneration were largely distinct from those for limb development, despite the presence of common patterning molecules. Intercalation has been an important concept to explain salamander limb regeneration, but clear evidence supporting or refuting this model was lacking. In the intercalation model, the first blastema cells acquire fingertip identity, creating a gap in positional identity that triggers regeneration of the intervening region from the stump. We used HOXA protein analysis and transplantation assays to show that axolotl limb blastema cells acquire positional identity in a proximal-to-distal sequence. Therefore, intercalation is not the primary mechanism for segment formation during limb regeneration in this animal. Patterning in development and regeneration uses similar mechanisms.


Assuntos
Extremidades/fisiologia , Proteínas de Homeodomínio/metabolismo , Regeneração , Ambystoma mexicanum , Animais , Padronização Corporal , Extremidades/anatomia & histologia , Dados de Sequência Molecular
16.
PLoS One ; 8(5): e61352, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23658691

RESUMO

Understanding how the limb blastema is established after the initial wound healing response is an important aspect of regeneration research. Here we performed parallel expression profile time courses of healing lateral wounds versus amputated limbs in axolotl. This comparison between wound healing and regeneration allowed us to identify amputation-specific genes. By clustering the expression profiles of these samples, we could detect three distinguishable phases of gene expression - early wound healing followed by a transition-phase leading to establishment of the limb development program, which correspond to the three phases of limb regeneration that had been defined by morphological criteria. By focusing on the transition-phase, we identified 93 strictly amputation-associated genes many of which are implicated in oxidative-stress response, chromatin modification, epithelial development or limb development. We further classified the genes based on whether they were or were not significantly expressed in the developing limb bud. The specific localization of 53 selected candidates within the blastema was investigated by in situ hybridization. In summary, we identified a set of genes that are expressed specifically during regeneration and are therefore, likely candidates for the regulation of blastema formation.


Assuntos
Proteínas de Anfíbios/genética , Extremidades/fisiologia , Regulação da Expressão Gênica/fisiologia , Regeneração , Transcriptoma , Ambystoma mexicanum , Proteínas de Anfíbios/metabolismo , Animais , Análise por Conglomerados , Perfilação da Expressão Gênica , Ontologia Genética , Análise de Sequência com Séries de Oligonucleotídeos , Estresse Fisiológico , Regulação para Cima , Cicatrização
17.
Dev Biol ; 373(1): 196-204, 2013 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-23103585

RESUMO

Limb regeneration involves re-establishing a limb development program from cells within adult tissues. Identifying molecular handles that provide insight into the relationship between cell differentiation status and cell lineage is an important step to study limb blastema cell formation. Here, using single cell PCR, focusing on newly isolated Twist1 sequences, we molecularly profile axolotl limb blastema cells using several progenitor cell markers. We link their molecular expression profile to their embryonic lineage via cell tracking experiments. We use in situ hybridization to determine the spatial localization and extent of overlap of different markers and cell types. Finally, we show by single cell PCR that the mature axolotl limb harbors a small but significant population of Twist1(+) cells.


Assuntos
Ambystoma mexicanum/fisiologia , Tecido Conjuntivo/metabolismo , Extremidades/fisiologia , Músculo Esquelético/metabolismo , Regeneração/fisiologia , Células-Tronco/metabolismo , Proteína 1 Relacionada a Twist/metabolismo , Animais , Linhagem da Célula/fisiologia , Células do Tecido Conjuntivo/metabolismo , Hibridização In Situ , Mesoderma/citologia , Músculo Esquelético/citologia , Reação em Cadeia da Polimerase , Pele/citologia , Transcriptoma
18.
Nat Commun ; 3: 1279, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23232409

RESUMO

The evolutionary origins of the gene network underlying cellular pluripotency, a central theme in developmental biology, have yet to be elucidated. In mammals, Oct4 is a factor crucial in the reprogramming of differentiated cells into induced pluripotent stem cells. The Oct4 and Pou2 genes evolved from a POU class V gene ancestor, but it is unknown whether pluripotency induced by Oct4 gene activity is a feature specific to mammals or was already present in ancestral vertebrates. Here we report that different vertebrate Pou2 and Oct4 homologues can induce pluripotency in mouse and human fibroblasts and that the inability of zebrafish Pou2 to establish pluripotency is not representative of all Pou2 genes, as medaka Pou2 and axolotl Pou2 are able to reprogram somatic cells into pluripotent cells. Therefore, our results indicate that induction of pluripotency is not a feature specific to mammals, but existed in the Oct4/Pou2 common ancestral vertebrate.


Assuntos
Diferenciação Celular/fisiologia , Fator 3 de Transcrição de Octâmero/fisiologia , Células-Tronco Pluripotentes/fisiologia , Vertebrados/fisiologia , Proteínas de Peixe-Zebra/fisiologia , Adulto , Ambystoma mexicanum/embriologia , Ambystoma mexicanum/fisiologia , Animais , Evolução Biológica , Clonagem Molecular , Feminino , Fibroblastos/fisiologia , Humanos , Hibridização In Situ , Camundongos , Pessoa de Meia-Idade , Oryzias/fisiologia , Filogenia , Peixe-Zebra/fisiologia
19.
Proc Natl Acad Sci U S A ; 109(34): E2258-66, 2012 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-22829665

RESUMO

We show that after tail amputation in Ambystoma mexicanum (Axolotl) the correct number and spacing of dorsal root ganglia are regenerated. By transplantation of spinal cord tissue and nonclonal neurospheres, we show that the central spinal cord represents a source of peripheral nervous system cells. Interestingly, melanophores migrate from preexisting precursors in the skin. Finally, we demonstrate that implantation of a clonally derived spinal cord neurosphere can result in reconstitution of all examined cell types in the regenerating central spinal cord, suggesting derivation of a cell with spinal cord stem cell properties.


Assuntos
Sistema Nervoso Central/fisiologia , Sistema Nervoso Periférico/fisiologia , Regeneração/fisiologia , Cauda/fisiologia , Sequência de Aminoácidos , Animais , Gânglios Espinais/metabolismo , Proteínas de Fluorescência Verde/metabolismo , Proteínas de Homeodomínio/metabolismo , Modelos Biológicos , Dados de Sequência Molecular , Medula Espinal/citologia , Células-Tronco/citologia , Urodelos
20.
Zoolog Sci ; 28(11): 809-16, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22035303

RESUMO

The epidermis serves as a barrier protecting organs and tissues from the environment, and comprises many types of cells. A cell renewal system is established in epidermis: old epithelial cells are replaced by newly differentiated cells, which are derived from epidermal stem cells located near basement membrane. In order to examine the mechanism of epidermal development, we isolated a novel gene expressed in Xenopus epidermis and named the gene Xenopus polka dots (Xpod) from its polka dot-like expression pattern throughout larval periods. Several immunohistochemical examinations showed that the Xpod-expressing cell type is neither p63-positive epidermal stem cells, nor the α-tubulin-positive ciliated cells, but a subset of the foxi1e-positive ionocytes. The forced gene expression of foxi1e caused the suppression of Xpod expression, while Xpod showed no effect on foxi1e expression. In a comparison of several osmotic conditions, we found that hypertonic culture caused the increase in number of the Xpod-expressing cell, whereas number of the foxi1e-expressing cells was reduced under the hypertonic condition. These results show the possibility that Xpod is involved in the establishment of a certain subpopulation of ionocytes under hypertonic conditions.


Assuntos
Epiderme/embriologia , Epiderme/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Proteínas de Xenopus/metabolismo , Xenopus laevis/embriologia , Xenopus laevis/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Embrião não Mamífero/metabolismo , Larva/genética , Larva/metabolismo , Dados de Sequência Molecular , Proteínas de Xenopus/genética , Xenopus laevis/genética
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