RESUMEN
Nasal olfactory stem and neural progenitor cells (NOS/PCs) are considered possible tools for regenerative stem cell therapies in neurodegenerative diseases. Neurogenesis is a complex process regulated by extrinsic and intrinsic signals that include DNA-methylation and other chromatin modifications that could be experimentally manipulated in order to increase neuronal differentiation. The aim of the present study was the characterization of primary cultures and consecutive passages (P2-P10) of NOS/PCs isolated from male Swiss-Webster (mNOS/PCs) or healthy humans (hNOS/PCs). We evaluated and compared cellular morphology, proliferation rates and the expression pattern of pluripotency-associated markers and DNA methylation-associated gene expression in these cultures. Neuronal differentiation was induced by exposure to all-trans retinoic acid and forskolin for 7 days and evaluated by morphological analysis and immunofluorescence against neuronal markers MAP2, NSE and MAP1B. In response to the inductive cues mNOS/PCs expressed NSE (75.67%) and MAP2 (35.34%); whereas the majority of the hNOS/PCs were immunopositive to MAP1B. Treatment with procainamide, a specific inhibitor of DNA methyltransferase 1 (DNMT1), increases in the number of forskolin'/retinoic acid-induced mature neuronal marker-expressing mNOS/PCs cells and enhances neurite development in hNOS/PCs. Our results indicate that mice and human nasal olfactory stem/progenitors cells share pluripotency-related gene expression suggesting that their application for stem cell therapy is worth pursuing and that DNA methylation inhibitors could be efficient tools to enhance neuronal differentiation from these cells.
Asunto(s)
Diferenciación Celular/efectos de los fármacos , Colforsina/farmacología , ADN (Citosina-5-)-Metiltransferasas/metabolismo , Células-Madre Neurales/efectos de los fármacos , Neuronas/efectos de los fármacos , Mucosa Olfatoria/citología , Tretinoina/farmacología , Animales , Células Cultivadas , ADN (Citosina-5-)-Metiltransferasa 1 , Metilación de ADN/efectos de los fármacos , Humanos , Masculino , Ratones , Proteínas del Tejido Nervioso/metabolismo , Factores de TiempoRESUMEN
Aging increases the vulnerability to stress and risk of developing depression. These changes have been related to a reduction of dehydroepiandrosterone (DHEA) levels, an adrenal steroid with anti-stress effects. Also, adult hippocampal neurogenesis decreases during aging and its alteration or impaired is related to the development of depression. Besides, it has been hypothesized that DHEA increases the formation of new neurons. However, it is unknown whether treatment with DHEA in aging may stimulate the dendrite maturation of newborn neurons and reversing depressive-like signs evoked by chronic stress exposure. Here aged male rats (14 months old) were subjected to a scheme of chronic mild stress (CMS) during six weeks, received a treatment with DHEA from the third week of CMS. Changes in body weight and sucrose preference (SP) were measured once a week. DHEA levels were measured in serum, identification of doublecortin-(DCX)-, BrdU- and BrdU/NeuN-labeled cells was done in the dentate gyrus of the hippocampus. CMS produced a gradual reduction in the body weight, but no changes in the SP were observed. Treatment enhanced levels of DHEA, but lack of recovery on body weight of stressed rats. Aging reduced the number of DCX-, BrdU- and BrdU/NeuN- cells but DHEA just significantly increased the number of DCX-cells in rats under CMS and controls, reaching levels of young non-stressed rats (used here as a reference of an optimal status of health). In rats under CMS, DHEA facilitated dendritic maturation of immature new neurons. Our results reveal that DHEA improves neural plasticity even in conditions of CMS in middle age rats. Thus, this hormone reverted the decrement of DCX-cells caused during normal aging.
Asunto(s)
Envejecimiento/efectos de los fármacos , Deshidroepiandrosterona/farmacología , Dendritas/efectos de los fármacos , Giro Dentado/efectos de los fármacos , Psicotrópicos/farmacología , Estrés Psicológico/tratamiento farmacológico , Envejecimiento/fisiología , Envejecimiento/psicología , Animales , Antígenos Nucleares/metabolismo , Peso Corporal/efectos de los fármacos , Bromodesoxiuridina , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/fisiología , Enfermedad Crónica , Deshidroepiandrosterona/sangre , Dendritas/metabolismo , Dendritas/patología , Giro Dentado/metabolismo , Giro Dentado/patología , Sacarosa en la Dieta , Proteínas de Dominio Doblecortina , Proteína Doblecortina , Masculino , Proteínas Asociadas a Microtúbulos/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Neurogénesis/efectos de los fármacos , Neurogénesis/fisiología , Neuropéptidos/metabolismo , Psicotrópicos/sangre , Distribución Aleatoria , Ratas Wistar , Estrés Psicológico/metabolismo , Estrés Psicológico/patologíaRESUMEN
Epigallo-catechin-3-gallate (EGCG), found in the leaves of Camellia sinensis (green tea), has antioxidant- and scavenger-functions and acts neuroprotectively. It has been publicized as anti-aging remedy but data on potential cellular mechanisms are scarce. Recent studies claimed that EGCG specifically promotes neural precursor cell proliferation in the dentate gyrus of C57Bl/6 mice, without changes at the level of immature and mature new neurons. We here analyzed the effects of EGCG on adult hippocampal neurogenesis in male Balb/C mice and saw a different pattern. Two weeks of treatment with EGCG (0, 0.625, 1.25, 2.5, 5 and 10mg/kg) showed a dose-response curve that peaked at 2.5mg/kg of EGCG with significantly increased cell survival without affecting cell proliferation but decreasing apoptotic cells. Also, EGCG increased the population of doublecortin-(DCX)-expressing cells that comprises the late intermediate progenitor cells (type-2b and -3) as well as immature neurons. After EGCG treatment, the young DCX-positive neurons showed more elaborated dendritic trees. EGCG also significantly increased net neurogenesis in the adult hippocampus and increased the hippocampal levels of phospho-Akt. Ex vivo, EGCG exerted a direct effect on survival and neuronal differentiation of adult hippocampal precursor cells, which was absent, when PI3K, a protein upstream of Akt, was blocked. Our results thus support a pro-survival and a pro-neurogenic role of EGCG. In the context of the conflicting published results, however, potential genetic modifiers must be assumed. These might help to explain the overall variability of study results with EGCG. Our data do indicate, however, that natural compounds such as EGCG can in principle modulate brain plasticity.
Asunto(s)
Catequina/análogos & derivados , Supervivencia Celular/efectos de los fármacos , Hipocampo/efectos de los fármacos , Neurogénesis/efectos de los fármacos , Neuronas/efectos de los fármacos , Fármacos Neuroprotectores/farmacología , Animales , Catequina/química , Catequina/farmacología , Supervivencia Celular/fisiología , Células Cultivadas , Relación Dosis-Respuesta a Droga , Proteínas de Dominio Doblecortina , Proteína Doblecortina , Hipocampo/fisiología , Masculino , Ratones Endogámicos BALB C , Proteínas Asociadas a Microtúbulos/metabolismo , Células-Madre Neurales/efectos de los fármacos , Células-Madre Neurales/fisiología , Neurogénesis/fisiología , Neuronas/fisiología , Neuropéptidos/metabolismo , Fármacos Neuroprotectores/química , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Té/químicaRESUMEN
Brain imaging and histopathological studies suggest that neurodevelopmental anomalies play a key role in the etiology of schizophrenia (SZ) and bipolar disorder (BD). New neuron formation and maturation occur in human olfactory epithelium throughout life. Therefore, the olfactory epithelium has been proposed as a model to study alterations in neurodevelopment, particularly in some psychiatric diseases. However, former studies were done with olfactory epithelium biopsies taken post mortem or under anesthesia from patients with SZ and BD. In this work we have developed a new method to obtain viable neural precursors by exfoliation of the anterior region of the medial lateral turbinate of the nasal cavity from healthy controls, and ambulatory patients. Cells were propagated to establish neural precursor banks. Thawed cells showed cytoskeletal phenotypes typical of developing neurons. They also conserved the ability to differentiate in presence of 2mM dibutyril-cyclic adenosine monophosphate, and maintained voltage-operated Ca(2+) currents in culture. Moreover, proportions of neuronal maturation stages were maintained in cultured exfoliates obtained from SZ and BD patients. Data support that neural precursors obtained from a nasal exfoliate are an excellent experimental model to later approach studies on biomarkers, neural development and cellular alterations in the pathophysiology of SZ and BD.