Terapia génica con GDNF mediante vectores adenovirales recombinantes en un modelo murino de neurodegeneración dopaminérgica senil

El envejecimiento está asociado a un progresivo aumento de la incidencia de enfermedades neurodegenerativas tanto en animales de laboratorio como en seres humanos. En el sistema nervioso central (SNC), las neuronas dopaminérgicas (DA) están entre las células más susceptibles a los efectos deletéreos de la edad. En el hombre, la enfermedad de Parkinson, una degeneración de las neuronas nigroestriatales DA que afecta al 0.1-0,5 % de la población, es el reflejo más conspicuo de la vulnerabilidad de las neuronas DA al envejecimiento. En la rata, el envejecimiento trae aparejada una progresiva degeneración y pérdida de otro grupo de neuronas DA centrales a saber, las neuronas DA tuberoinfundibulares (TIDA) las cuales ejercen un control inhibitorio tónico sobre la secreción de prolactina (PRL) y la proliferación lactotropa en la adenohipófisis. La pérdida excesiva de neuronas TIDA durante el envejecimiento normal está asociada, en la rata hembra, con una progresiva hiperprolactinemia y con el desarrollo de prolactinomas hipofisarios. Debe destacarse que a los 30 meses de edad las ratas hembras Sprague Dawley pierden un 40 % de sus neuronas DA nigrales, constituyendo de este modo un modelo animal único de neurodegeneración DA espontánea tanto a nivel hipotalámico como nigral. Una posibilidad terapéutica de creciente interés clínico en el tratamiento de procesos neurodegenerativos es el empleo de factores neurotróficos que prevengan la degeneración y restauren la función de la población neuronal remanente. A principios de la década de 1990, Martha Bohn y col., Northwestern University, Chicago, descubrieron que la línea celular tumoral glial B49 secreta un factor que promueve la sobrevida y diferenciación de las neuronas DA mesencefálicas. Este nuevo factor neurotrófico, denominado factor neurotrófico derivado de la glia (GDNF), resultó ser un glicopéptido de 211 aminoácidos cuyo gen ha sido clonado. El GDNF, un miembro lejano de la superfamilia del TGFβ, posee una potente y específica capacidad para promover la captación de dopamina, la supervivencia de neuronas DA embrionarias y la regeneración de neuronas DA en roedores y primates no humanos tratados con neurotoxinas DA. El GDNF es efectivo para proteger no sólo las neuronas DA nigrales sino también para proteger ciertas poblaciones neuronales colinérgicas y de otro tipo, lo cual hace de esta molécula un candidato promisorio para el tratamiento de patologías neurodegenerativas, tales como la enfermedad de Parkinson, Lou Gehrig y Alzheimer.Eje: Virología molecularInstituto de Investigaciones Bioquímicas de La Plat

Caracterización del déficit cognitivo y los cambios neurales que ocurren en la rata de mediana edad

Estudios en humanos y en animales de laboratorio han mostrado un importante deterioro en la memoria y el aprendizaje con la edad. Muchos trabajos donde se examinan habilidades cognitivas en ratas muestran una importante diferencia entre ratas jóvenes y viejas (20 meses o más), cuando se utilizan pruebas de comportamiento como el Laberinto de Barnes. Sin embargo, algunos trabajos muestran que el deterioro cognitivo comienza a producirse en la mediana edad (12 meses), ya que los procesos de memoria y aprendizaje evaluados en los tests dependen principalmente del hipocampo, una estructura que empieza a mostrar un deterioro funcional alrededor de los 12 meses. La neurogénesis se puede ver reflejada por el número de neuroblastos doblecortina (DCX) positivos en el hipocampo de la rata, y se ha encontrado una dramática disminución con el. Sin embargo esta disminución de DCX en DG comienza mucho antes en la vida del animal y ha sido descripto que hay una disminución del 74% en ratas de mediana edad que luego se mantiene hasta el envejecimiento donde hay una segunda declinación que supera el 80% dependiendo de la cepa y el sexo.Facultad de Ciencias Médica

Caracterización del déficit cognitivo y los cambios neurales que ocurren en la rata de mediana edad

Estudios en humanos y en animales de laboratorio han mostrado un importante deterioro en la memoria y el aprendizaje con la edad. Muchos trabajos donde se examinan habilidades cognitivas en ratas muestran una importante diferencia entre ratas jóvenes y viejas (20 meses o más), cuando se utilizan pruebas de comportamiento como el Laberinto de Barnes. Sin embargo, algunos trabajos muestran que el deterioro cognitivo comienza a producirse en la mediana edad (12 meses), ya que los procesos de memoria y aprendizaje evaluados en los tests dependen principalmente del hipocampo, una estructura que empieza a mostrar un deterioro funcional alrededor de los 12 meses. La neurogénesis se puede ver reflejada por el número de neuroblastos doblecortina (DCX) positivos en el hipocampo de la rata, y se ha encontrado una dramática disminución con el. Sin embargo esta disminución de DCX en DG comienza mucho antes en la vida del animal y ha sido descripto que hay una disminución del 74% en ratas de mediana edad que luego se mantiene hasta el envejecimiento donde hay una segunda declinación que supera el 80% dependiendo de la cepa y el sexo.Facultad de Ciencias Médica

Role of Copper and Cholesterol association in the neurodegenerative process

Age is one of the main factors involved in the development of neurological illnesses, in particular, Alzheimer, and it is widely held that the rapid aging of the world population is accompanied by a rise in the prevalence and incidence of Alzheimer disease. However, evidence from recent decades indicates that Cu and Cho overload are emerging causative factors in neurodegeneration, a hypothesis that has been partially investigated in experimental models. The link between these two variables and the onset of Alzheimer disease has opened up interesting new possibilities requiring more in-depth analysis. The aim of the present study was therefore to investigate the effect of the association of Cu + Cho (CuCho) as a possible synergistic factor in the development of an Alzheimer-like pathology in Wistar rats. We measured total- and nonceruloplasmin-bound Cu and Cho (free and sterified) contents in plasma and brain zones (cortex and hippocampus), markers of oxidative stress damage, inflammation, and programmed cell death (caspase-3 and calpain isoforms). The ratio beta-amyloid (1-42)/(1-40) was determined in plasma and brain as neurodegenerative biomarker. An evaluation of visuospatial memory (Barnes maze test) was also performed. The results demonstrate the establishment of a prooxidative and proinflammatory environment after CuCho treatment, hallmarked by increased TBARS, protein carbonyls, and nitrite plus nitrate levels in plasma and brain zones (cortex and hippocampus) with a consequent increase in the activity of calpains and no significant changes in caspase-3. A simultaneous increase in the plasma A1-42/A1-40 ratio was found. Furthermore, a slight but noticeable change in visuospatial memory was observed in rats treated with CuCho. We conclude that our model could reflect an initial stage of neurodegeneration in which Cu and Cho interact with one another to exacerbate neurological damage.Fil: Arnal, Nathalie. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Bioquímicas de la Plata; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Médicas; ArgentinaFil: Morel, Gustavo Ramón. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Bioquímicas de la Plata; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Médicas; ArgentinaFil: Tacconi, Maria Josefa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Bioquímicas de la Plata; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Médicas; ArgentinaFil: Castillo, Hector Omar. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnológico La Plata. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani"; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Médicas; ArgentinaFil: Marra, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Bioquímicas de la Plata; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Médicas; Argentin

Identification of a Conserved Gene Signature Associated with an Exacerbated Inflammatory Environment in the Hippocampus of Aging Rats

There have been a few descriptive studies in aged rodents about transcriptome changes in the hippocampus, most of them in males. Here, we assessed the age changes in spatial memory performance and hippocampal morphology in female rats and compared those changes with changes in the hippocampal transcriptome. Old rats displayed significant deficits in spatial memory. In both age groups, hole exploration frequency showed a clear peak at hole 0 (escape hole), but the amplitude of the peak was significantly higher in the young than in the old animals. In the hippocampus, there was a dramatic reduction in neurogenesis, whereas reactive microglial infiltrates revealed an inflammatory hippocampal state in the senile rats. Hippocampal RNA‐sequencing showed that 210 genes are differentially expressed in the senile rats, most of them being downregulated. Our RNA‐Seq data showed that various genes involved in the immune response, including TYROBP, CD11b, C3, CD18, CD4, and CD74, are overexpressed in the hippocampus of aged female rats. Enrichment analysis showed that the pathways overrepresented in the senile rats matched those of an exacerbated inflammatory environment, reinforcing our morphologic findings. After correlating our results with public data of human and mouse hippocampal gene expression, we found an 11‐gene signature of overexpressed genes related to inflammatory processes that was conserved across species. We conclude that age‐related hippocampal deficits in female rats share commonalities between human and rodents. Interestingly, the 11‐gene signature that we identified may represent a cluster of immune and regulatory genes that are deregulated in the hippocampus and possibly other brain regions during aging as well as in some neurodegenerative diseases and low‐grade brain tumors. Our study further supports neuroinflammation as a promising target to treat cognitive dysfunction in old individuals and some brain tumors.Instituto de Investigaciones Bioquímicas de La PlataCentro de Investigaciones Inmunológicas Básicas y Aplicada

Role of copper and cholesterol association in the neurodegenerative process

Age is one of the main factors involved in the development of neurological illnesses, in particular, Alzheimer, and it is widely held that the rapid aging of the world population is accompanied by a rise in the prevalence and incidence of Alzheimer disease. However, evidence from recent decades indicates that Cu and Cho overload are emerging causative factors in neurodegeneration, a hypothesis that has been partially investigated in experimental models. The link between these two variables and the onset of Alzheimer disease has opened up interesting new possibilities requiring more in-depth analysis. The aim of the present study was therefore to investigate the effect of the association of Cu + Cho (CuCho) as a possible synergistic factor in the development of an Alzheimer-like pathology in Wistar rats. We measured total- and nonceruloplasmin-bound Cu and Cho (free and sterified) contents in plasma and brain zones (cortex and hippocampus), markers of oxidative stress damage, inflammation, and programmed cell death (caspase-3 and calpain isoforms). The ratio beta-amyloid (1-42)/(1-40) was determined in plasma and brain as neurodegenerative biomarker. An evaluation of visuospatial memory (Barnes maze test) was also performed. The results demonstrate the establishment of a prooxidative and proinflammatory environment after CuCho treatment, hallmarked by increased TBARS, protein carbonyls, and nitrite plus nitrate levels in plasma and brain zones (cortex and hippocampus) with a consequent increase in the activity of calpains and no significant changes in caspase-3. A simultaneous increase in the plasma Aβ1-42/Aβ1-40 ratio was found. Furthermore, a slight but noticeable change in visuospatial memory was observed in rats treated with CuCho. We conclude that our model could reflect an initial stage of neurodegeneration in which Cu and Cho interact with one another to exacerbate neurological damage.Instituto de Investigaciones Bioquímicas de La PlataCentro de Investigaciones Cardiovasculare

Age-related loss of recognition memory and its correlation with hippocampal and perirhinal cortex changes in female Sprague Dawley rats

Ageing is associated with impaired performance in recognition memory, a process that consists of the discrimination of familiar and novel stimuli. Previous studies have shown the impact of ageing on object recognition memories. However, the early stages of memory impairment remain unknown. To fill this gap, we aimed at evaluating the ability of young (Y), middle-aged (MA), and senile (S) female Sprague-Dawley rats to retain 24 h long-term recognition memory. The MA cohort was included to characterise early memory deficits under two behavioural paradigms based on spontaneous location recognition (SLR) and spontaneous object recognition (SOR) tasks. In the SLR task, there was a markedly diminished novel discrimination capacity in the MA and S rats compared with the Y ones. In the SOR task, S rats evidenced a deterioration in novelty discrimination, while MA rats partially preserved the capacity to distinguish the new stimulus as compared with Y rats. Regarding early changes from MA to S rats, immunohistochemistry showed a marked decrease in the number and diameter of adult-born immature neurons in the Dentate Gyrus (DG) with a positive correlation with behavioural performance in the SLR task. Furthermore, we found a slight reduction in CA3 mature neurons and a decrease in the number of total microglia in the perirhinal cortex (Prh) in MA and S rats as compared with Y rats. As regards changes that were only observed in S rats, we found an increase in the number of total and reactive microglia in CA3 and a reduction in the number of total microglia in the DG. We conclude that spatial discrimination capacity could be affected earlier than feature discrimination capacity. We suggest that early depletion of neurogenesis in MA rats is involved in object location recognition deficits, whereas the disruption of microglial homeostasis in the Prh could be associated with object feature discrimination capacity.Instituto de Investigaciones Bioquímicas de La Plat

IGF-I Gene Therapy in Aging Rats Modulates Hippocampal Genes Relevant to Memory Function

In rats, learning and memory performance decline during normal aging, which makes this rodent species a suitable model to evaluate therapeutic strategies. In aging rats, insulin-like growth factor-I (IGF-I), is known to significantly improve spatial memory accuracy as compared to control counterparts. A constellation of gene expression changes underlie the hippocampal phenotype of aging but no studies on the effects of IGF-I on the hippocampal transcriptome of old rodents have been documented. Here, we assessed the effects of IGF-I gene therapy on spatial memory performance in old female rats and compared them with changes in the hippocampal transcriptome. In the Barnes maze test, experimental rats showed a significantly higher exploratory frequency of the goal hole than controls. Hippocampal RNA-sequencing showed that 219 genes are differentially expressed in 28 months old rats intracerebroventricularly injected with an adenovector expressing rat IGF-I as compared with placebo adenovector-injected counterparts. From the differentially expressed genes, 81 were down and 138 upregulated. From those genes, a list of functionally relevant genes, concerning hippocampal IGF-I expression, synaptic plasticity as well as neuronal function was identified. Our results provide an initial glimpse at the molecular mechanisms underlying the neuroprotective actions of IGF-I in the aging brain.Instituto de Investigaciones Bioquímicas de La PlataFacultad de Ciencias Médica

Transferencia génica asistida por magnetovectores en músculo esquelético

El objetivo del presente trabajo es determinar si la magnetofección puede constituir una alternativa eficiente para la transferencia génica in vitro e in vivo en células maduras del musculo esquelético.Facultad de Ciencias Médica

Transferencia génica asistida por magnetovectores en músculo esquelético

El objetivo del presente trabajo es determinar si la magnetofección puede constituir una alternativa eficiente para la transferencia génica in vitro e in vivo en células maduras del musculo esquelético.Facultad de Ciencias Médica