RESUMEN
Neural stem cells (NSC) can be isolated from a variety of adult tissues and become a valuable cell source for the repair of peripheral and central nervous diseases. However, their origin and identity remain controversial because of possible de-differentiation/trans-differentiation or contaminations by hematopoietic stem cells (HSCs) or mesenchymal stem cells (MSCs). We hypothesize that the commonly used NSC culture medium can induce committed cartilage chondrocytes to de-differentiate and/or trans-differentiate into neural cell lineages. Using a biological isolation and purification method with explants culture, we here show that adult rat clavicle cartilage chondrocytes migrate out from tissue blocks, form sphere-like structures, possess the capability of self-renewal, express nestin and p75NTR, markers for neural crest progenitors, and differentiate into neurons, glia, and smooth muscle cells. Comparing with adult cartilage, the spherical-forming neural crest cell-like cells downregulate the chondrocytic marker genes, including collagen II, collagen X, and sox9, as well as neural-lineage repressors/silencers REST and coREST, but upregulate a set of well-defined genes related to neural crest cells and pro-neural potential. Nerve growth factor (NGF) and glial growth factor (GGF) increase glial and neuronal differentiation, respectively. These results suggest that chondrocytes derived from adult clavicle cartilage can become neural crest stem-like cells and acquire neuronal phenotypes in vitro. The possible de-differentiation/trans-differentiation mechanisms underlying the conversion were discussed.
Asunto(s)
Linaje de la Célula , Condrocitos/citología , Clavícula/citología , Neuronas/citología , Animales , Biomarcadores/metabolismo , Bromodesoxiuridina/metabolismo , Diferenciación Celular/efectos de los fármacos , Linaje de la Célula/efectos de los fármacos , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Condrocitos/efectos de los fármacos , Clavícula/efectos de los fármacos , Colágeno Tipo X/genética , Regulación hacia Abajo/efectos de los fármacos , Femenino , Perfilación de la Expresión Génica , Péptidos y Proteínas de Señalización Intercelular/farmacología , Proteínas de Filamentos Intermediarios/genética , Masculino , Microscopía de Contraste de Fase , Proteínas del Tejido Nervioso/genética , Nestina , Neuronas/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Esferoides Celulares/citología , Esferoides Celulares/efectos de los fármacos , Regulación hacia Arriba/efectos de los fármacosRESUMEN
Dentro de la estimación forense de la edad, las recomendaciones del AGFAD establecen la práctica de estudios de radiología de la clavícula para el diagnóstico de la edad en la franja entre los 18 y 21 años de edad. Se presenta un estudio sobre una muestra de 123 radiografías digitales de tórax de sujetos entre 5 y 75 años de edad en las que se ha analizado el estado de fusión de la epífisis esternal de la clavícula. En este estudio la edad mínima a la que se ha podido valorar la existencia de un estado de fusión completa (estadios 4 y 5 de Schmeling) ha sido de 19,7 años. Se analiza la bibliografía actualizada sobre este fenómeno y se apuntan una serie de sugerencias adicionales a las propuestas por AGFAD
In 2000 the AGFAD published their recommendations about forensic age estimations. They recommended an X ray of the clavicle (collar bone) in cases of subjects between 18 and 21 years of age. We present a study on stages of fusion of clavicle sternal epiphyses in a 123 digital X-rays from a population sample between 5 and 75 years of age. In our research minimum age at which complete fusion was achived (stages 4 or 5 in Schmeling method) has been 19,7 years of chronological age. A review of the medico legal literature about age estimation based on sternal end of the clavicle has been included. It´s pointed out that forensic experts should bear in mind some suggestions when applying AGFAD recommendations to obtain an age estimation based in clavicle X-rays
Asunto(s)
Masculino , Femenino , Niño , Adolescente , Adulto , Persona de Mediana Edad , Humanos , Epífisis/citología , Epífisis/ultraestructura , Clavícula/citología , Clavícula/ultraestructura , Determinación de la Edad por el Esqueleto/métodos , Radiografía Torácica , Procesamiento de Imagen Asistido por Computador/métodos , Diagnóstico por Imagen/métodos , Anatomía Comparada/métodos , Anatomía Comparada/tendencias , Radiación/clasificaciónRESUMEN
The extracellular signal-regulated kinase (ERK)-mitogen-activated protein kinase (MAPK) pathway provides a major link between the cell surface and nucleus to control proliferation and differentiation. However, its in vivo role in skeletal development is unknown. A transgenic approach was used to establish a role for this pathway in bone. MAPK stimulation achieved by selective expression of constitutively active MAPK/ERK1 (MEK-SP) in osteoblasts accelerated in vitro differentiation of calvarial cells, as well as in vivo bone development, whereas dominant-negative MEK1 was inhibitory. The involvement of the RUNX2 transcription factor in this response was established in two ways: (a) RUNX2 phosphorylation and transcriptional activity were elevated in calvarial osteoblasts from TgMek-sp mice and reduced in cells from TgMek-dn mice, and (b) crossing TgMek-sp mice with Runx2+/- animals partially rescued the hypomorphic clavicles and undemineralized calvaria associated with Runx2 haploinsufficiency, whereas TgMek-dn; Runx2+/- mice had a more severe skeletal phenotype. This work establishes an important in vivo function for the ERK-MAPK pathway in bone that involves stimulation of RUNX2 phosphorylation and transcriptional activity.
Asunto(s)
Desarrollo Óseo , Diferenciación Celular , Sistema de Señalización de MAP Quinasas/fisiología , Osteoblastos/citología , Animales , Animales Modificados Genéticamente , Diferenciación Celular/genética , Clavícula/anatomía & histología , Clavícula/citología , Clavícula/enzimología , Subunidad alfa 1 del Factor de Unión al Sitio Principal/genética , Subunidad alfa 1 del Factor de Unión al Sitio Principal/metabolismo , Subunidad alfa 1 del Factor de Unión al Sitio Principal/fisiología , MAP Quinasa Quinasa 1/genética , MAP Quinasa Quinasa 1/metabolismo , Ratones , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Osteoblastos/enzimología , Fenotipo , Fosforilación , Cráneo/anatomía & histología , Cráneo/citología , Cráneo/enzimología , Transcripción Genética , TransgenesRESUMEN
The deployment of the cranial neural crest is central to the patterning of the skeletomuscular elements of the vertebrate head, with cranial muscles invariably attaching to skeletal elements formed by crest from the same axial level. Here we demonstrate, through gene expression analysis, ablation studies and fate-mapping, the existence of a population of caudally migrating cranial crest that arise from the postotic neural tube. As with the rest of the postotic crest, these cells express the transcription factor Mafb, and this marker can be used to highlight their posterior migration. They pass out between the anterior somite and the otic vesicle, before turning caudally and running along the base of the somites. With long-term fate mapping, we show that these cells migrate to the clavicle and settle at the site of formation of the attachment point for the cleidohyoid muscle. As such, the influence of the cranial neural crest in organising skeletomuscular connectivity seems to extend beyond the head into the trunk. These results are of further importance as they help explain how, even though the pectoral girdle and the skull became physically dissociated during tetrapod evolution, skeletomuscular connectivity has been maintained.
Asunto(s)
Proteínas Aviares , Movimiento Celular , Proteínas de Unión al ADN , Embrión de Mamíferos/citología , Embrión de Mamíferos/embriología , Cresta Neural/citología , Cresta Neural/embriología , Cráneo/citología , Cráneo/embriología , Factores de Transcripción , Animales , Evolución Biológica , Encéfalo/citología , Encéfalo/embriología , Linaje de la Célula , Embrión de Pollo , Clavícula/citología , Clavícula/embriología , Embrión no Mamífero/citología , Embrión no Mamífero/embriología , Femenino , Hibridación in Situ , Factor de Transcripción MafB , Ratones , Neuronas/citología , Lóbulo Occipital/citología , Lóbulo Occipital/embriología , Proteínas Oncogénicas/genética , Codorniz/embriología , ARN Mensajero/análisis , ARN Mensajero/genética , Transactivadores/genética , Trasplante HeterólogoRESUMEN
The histological method developed by Stout and Paine ([1992] Aln. J. Phys. Antropol. 87:111-115) for estimating age at death using the clavicle is tested on a known age independent sample from a nineteenth century cemetery near Spitalfriedhof St. Johann in Basel, Switzerland. The mean absolute difference between reported ages and histologically predicted ages is 5.5 years. Mean predicted age for the sample is different from mean reported age. This difference is accounted for by differences in the age distributions between the original autopsy sample used to derive the histological age-predicting formula and the cemetery sample, and an inherent loss of reliability of histological age predictions for the skeletal remains of older individuals. A new formula based upon the combined original autopsy sample of Stout and Paine (1992) and the Swiss cemetery sample is presented. It is recommended that this formula be used when estimating ages for older individuals or archaeological skeletal samples.