Coexpresión de NG2/GFAP tras la diferenciación en células transfectadas con las mutaciones de GFAP y en células procedentes de gliomas indiferenciados / NG2 and GFAP co-expression after differentiation in cells transfected with mutant GFAP and in undifferentiated glioma cells

INTRODUCCIÓN: La enfermedad de Alexander es una enfermedad rara causada por mutaciones en el gen que codifica la proteína glial ácida fibrilar (GFAP). En un estudio previo hemos observado que la diferenciación de neuroesferas transfectadas con estas mutaciones genera un tipo celular que comparte la expresión de GFAP y NG2. OBJETIVOS: Determinar el efecto de las mutaciones en marcadores moleculares en comparación con células de glioma diferenciados que expresan simultáneamente GFAP y NG2. MÉTODOS: Se utilizaron muestras de glioblastoma humana (GLM) y neuroesferas procedentes de rata transfectadas con mutaciones de GFAP para el análisis de la expresión tras diferenciación de GFAP y NG2, así como el análisis inmunocitoquímico de diferenciación de ambos tipos celulares y detección de ambas proteínas, junto a nestina, vimentina, Olig2 y caspasa 3 a los 3 y 7 días de diferenciación. RESULTADOS: Tanto las células transfectadas con mutaciones de GFAP como las células procedentes de GLM mostraron un incremento de NG2 y GFAP. Sin embargo, la expresión de células caspasa 3 positiva era marcadamente mayor entre las células transfectadas que entre las células procedentes de GLM. CONCLUSIÓN: Nuestros resultados parecen indicar que la expresión de GFAP no es el único factor que condiciona la muerte celular en la enfermedad de Alexander y que la expresión de caspasa 3 y el potencial papel de la NG2 en incrementar la resistencia a la apoptosis en las células que coexpresan GFAP y NG2 deben ser considerados en la búsqueda de acciones terapéuticas en esta enfermedad

INTRODUCTION: Alexander disease is a rare disorder caused by mutations in the gene coding for glial fibrillary acidic protein (GFAP). In a previous study, differentiation of neurospheres transfected with these mutations resulted in a cell type that expresses both GFAP and NG2. OBJECTIVE: To determine the effect of molecular marker mutations in comparison to undifferentiated glioma cells simultaneously expressing GFAP and NG2. METHODS: We used samples of human glioblastoma (GBM) and rat neurospheres transfected with GFAP mutations to analyse GFAP and NG2 expression after differentiation. We also performed an immunocytochemical analysis of neuronal differentiation for both cell types and detection of GFAP, NG2, vimentin, Olig2, and aspase-3 at 3 and 7 days from differentiation. RESULTS. Both the cells transfected with GFAP mutations and GBM cells showed increased NG2 and GFAP expression. However, expression of caspase-3-positive cells was found to be considerably higher in transfected cells than in GBM cells. CONCLUSIONS: Our results suggest that GFAP expression is not the only factor associated with cell death in Alexander disease. Caspase-3 expression and the potential role of NG2 in increasing resistance to apoptosis in cells co-expressing GFAP and NG2 should be considered in the search for new therapeutic strategies for the disease

Desarrollo y optimización de un modelo animal para el estudio de las células ganglionares en enfermedad degenerativa de la retina y nervio óptico / Development and optimisation of an animal model for the study of ganglion cells in degenerative diseases of the retina and optic nerve

Introducción: La esclerosis múltiple es una enfermedad autoinmune, crónica e inflamatoria del sistema nervioso central con desmielinización axonal, gliosis y neurodegeneración. Considerada una causa frecuente de discapacidad neurológica en adultos jóvenes. En este trabajo, se ha optimizado un modelo de encefalomielitis autoinmune experimental (EAE), mediante la inyección de glicoproteína mielínica de los oligodendrocitos (MOG35-55), se han estudiado las repercusiones oftalmológicas, y se plantea su uso como modelo de experimentación en otros estudios de degeneración de las células ganglionares (CGR) y del nervio óptico (NO). Material y métodos: Dieciséis ratones de 10 semanas en 2 grupos de estudio: grupo control 10 animales y grupo con EAE 6 animales. Al grupo EAE se le inyectó MOG35-55. Los animales del modelo EAE, fueron monitorizados mediante escalas de discapacidad motora. Las retinas y los nervios ópticos se procesaron para examen morfológico a microscopia óptica y estudio ultraestructural. Resultados: Los modelos animales presentaron clínica motora de lesión medular, apareciendo los primeros síntomas entre el 7.°-19.° día postinyección. Con un promedio de discapacidad máxima de 3,5puntos. En retina, el promedio de CGR en el grupo EAE fue de 0,0891μm frente a 0,1678μm del grupo control (p = 0,0003). El NO se vio intensamente afectado con una gliosis reactiva, aumento del daño axonal y disminución de la densidad axonal (grupo control 0,38038 axones/μm2 frente al grupo EAE 0,16 axones/μm2; p = 0,00032). Conclusiones: En este trabajo hemos caracterizado y detallado un modelo animal de EAE para el estudio de alteraciones desmielinizantes en retina y NO. Sus características lo convierten en un magnífico instrumento para el estudio de las enfermedades oftalmológicas neurodegenerativas

Introduction: Multiple sclerosis is an autoimmune, chronic and inflammatory disease of the central nervous system with axonal demyelination, gliosis and neurodegeneration. It is considered a frequent cause of neurological disability in young adults. In this work, an Experimental Autoimmune Encephalomyelitis (EAE) model was optimised by injecting a myelin oligodendrocyte glycoprotein (MOG35-55). The ophthalmological effects were studied, as well as its use as an experimental model in other studies of retinal ganglion cell degeneration (RGC) and optic nerve (ON). Material and methods: The study included 16 mice of 10 weeks that were placed into 2 study groups: a control group of 10 animals and another group of 6 animals with EAE that were injected with MOG35-55. The animals of the EAE model were monitored using motor disability scales. The retinas and optic nerves were processed for morphological examination by optical microscopy and ultrastructure studies. Results: The animal models presented with motor symptoms of spinal cord injury, with the first symptoms appearing between the 7 th and 19 th day post-injection, with a maximum disability mean of 3.5 points. In the retina, the mean RGC in the EAE group was 0.0891 μm, compared with 0.1678 μm of the control group (p = .0003). The ON was strongly affected with reactive gliosis, increased axonal damage and decreased density axonal (control group 0.38038 axons/μm2 versus EAE group 0.16 axons/μm2, p = .00032). Conclusions: In this work an animal model of EAE has been characterised and detailed for the study of demyelinating alterations in the retina and the ON. Its characteristics make it an excellent tool for the study of neurodegenerative ophthalmic diseases

Proliferation in the human ipsilateral subventricular zone after ischemic stroke.

BACKGROUND: It is uncertain whether neurogenesis occurs in humans after stroke. We studied the morphologic changes that occurred in the subventricular zone (SVZ) in patients who died following an acute ischemic stroke. METHODS: We examined coronal brain slices from patients who died after a first-ever cerebral nonlacunar infarction in the middle cerebral artery territory. We evaluated the morphologic changes in the ipsilateral and contralateral SVZ by light and electron microscopy. Using immunochemistry with Ki-67 and PCNA, we detected cell proliferation. We used Tuj-1 for immature neurons and PSA-NCAM for migrating cells. RESULTS: The study included 7 patients with a mean age of 82 +/- 5 (mean +/- SD) years; 4 were men. They died a mean of 10 +/- 5 days after the ischemic stroke. Brain samples were obtained a mean of 4 +/- 2 hours after death. In comparison with the contralateral SVZ, the following changes were observed in the ipsilateral SVZ: an increase in the width of the gap and ribbon layers, as well as in the cell density of the ribbon layer, an enlargement of the cytoplasmic volume of astrocytes, and an increase of Ki-67-positive cells. In the ipsilateral SVZ, mitoses and cells that stained for either Tuj-1 or PSA-NCAM markers were observed more frequently than in the contralateral SVZ. CONCLUSION: We found unequivocal evidence of active cell proliferation in the ipsilateral subventricular zone following an acute ischemic stroke in our patients.

cGMP modulates stem cells differentiation to neurons in brain in vivo.

During brain development neural stem cells may differentiate to neurons or to other cell types. The aim of this work was to assess the role of cGMP (cyclic GMP) in the modulation of differentiation of neural stem cells to neurons or non-neuronal cells. cGMP in brain of fetuses was reduced to 46% of controls by treating pregnant rats with nitroarginine-methylester (L-NAME) and was restored by co-treatment with sildenafil.Reducing cGMP during brain development leads to reduced differentiation of stem cells to neurons and increased differentiation to non-neuronal cells. The number of neurons in the prefrontal cortex originated from stem cells proliferating on gestational day 14 was 715+/-14/mm(2) in control rats and was reduced to 440+/-29/mm(2) (61% of control) in rats treated with L-NAME. In rats exposed to L-NAME plus sildenafil, differentiation to neurons was completely normalized, reaching 683+/-11 neurons/mm(2). In rats exposed to sildenafil alone the number of cells labelled with bromodeoxyuridine (BrdU) and NeuN was 841+/-16/mm(2). In prefrontal cortex of control rats 48% of the neural stem cells proliferating in gestational day 14 differentiate to neurons, but only 24% in rats exposed to L-NAME. This was corrected by sildenafil, 40% of cells differentiate to neurons. Similar results were obtained for neurons proliferating during all developmental period. Treatment with L-NAME did not reduce the total number of cells labelled with BrdU, further supporting that L-NAME reduces selectively the differentiation of stem cells to neurons. Similar results were obtained in hippocampus. Treatment with L-NAME reduced the differentiation of neural stem cells to neurons, although the effect was milder than in prefrontal cortex. These results support that cGMP modulates the fate of neural stem cells in brain in vivo and suggest that high cGMP levels promote its differentiation to neurons while reduced cGMP levels promote differentiation to non-neuronal cells.

Spontaneous cardiomyocyte differentiation from adipose tissue stroma cells.

Cardiomyocyte regeneration is limited in adult life. Thus, the identification of a putative source of cardiomyocyte progenitors is of great interest to provide a usable model in vitro and new perspective in regenerative therapy. As adipose tissues were recently demonstrated to contain pluripotent stem cells, the emergence of cardiomyocyte phenotype from adipose-derived cells was investigated. We demonstrated that rare beating cells with cardiomyocyte features could be identified after culture of adipose stroma cells without addition of 5-azacytidine. The cardiomyocyte phenotype was first identified by morphological observation, confirmed with expression of specific cardiac markers, immunocytochemistry staining, and ultrastructural analysis, revealing the presence of ventricle- and atrial-like cells. Electrophysiological studies performed on early culture revealed a pacemaker activity of the cells. Finally, functional studies showed that adrenergic agonist stimulated the beating rate whereas cholinergic agonist decreased it. Taken together, this study demonstrated that functional cardiomyocyte-like cells could be directly obtained from adipose tissue. According to the large amount of this tissue in adult mammal, it could represent a useful source of cardiomyocyte progenitors.