164 research outputs found
Taller de prevención del alcoholismo para adolescentes
Este taller se realiza en establecimientos educativos de nivel secundario de Mar del Plata, con padres y alumnos de 1° año de la EES, ante la detección de casos de estudiantes que se presentaban alcoholizados a las clases de Educación FÃsica o no asistÃan a las mismas, por haberse alcoholizado la noche anterior. Después de realizar este taller en los últimos 4 años, nos encontramos con un obstáculo importante y es la poca participación e interés de los padres, ya que del total de alumnos invitados, concurre un 90de estudiantes y solo un 6de padres. La idea del taller es trabajar en conjunto con los integrantes de cada grupo familiar, primero, conociendo como se fabrican las distintas variedades de bebidas alcohólicas, y en segundo lugar los efectos que produce la ingesta de las mismas. También la posible complicidad que pueden tener algunos padres, al permitir que sus hijos realicen "la previa" en su casa, creyendo que es "mas seguro y económico", queriendo convertirse en "papá amigo", Se utilizan imágenes y pequeños videos sobre situaciones en donde hay alcohol, de esta manera se pone en primer plano diferentes contextos de personas alcoholizadas, analizándose la importancia de la prevención, en sus distintos niveles de intervención, como asà también la importancia del trabajo en equipo (profesores, padres y estudiantes), poniéndose de relieve estas conductas de riesgo, proponiendo una vida sana a través de la gimnasia, el juego y el deport
Estrogen receptors and signaling pathways in lactotropes and somatotropes
Estrogens are crucial determinants in the regulation of anterior pituitary function and maintenance of tissue homeostasis. Estrogen actions in this gland are exerted through both classical and non-classical mechanisms of action. This review summarizes the expression of classical α- and β-estrogen receptors and variant isoforms of estrogen receptors in anterior pituitary cell subpopulations. We also analyze estrogen receptor signaling pathways involved in estrogenic actions in the anterior pituitary gland, especially in lactotropes and somatotropes. Complex interactions between multiple signaling pathways are involved in estrogen regulation of hormone secretion, cell proliferation and cell death in this gland. Insight into these pituitary responses to estrogens would help to understand pituitary function and tumorigenesis.Fil: Zarate, Sandra Cristina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de BiologÃa Celular e HistologÃa. Centro de Investigación en Reproducción; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Seilicovich, Adriana. Universidad de Buenos Aires. Facultad de Medicina. Departamento de BiologÃa Celular e HistologÃa. Centro de Investigación en Reproducción; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; Argentin
Hormone deprivation alters mitochondrial function and lipid profile in the hippocampus
Mitochondrial dysfunction is a common hallmark in aging. In the female, reproductive senescence is characterized by loss of ovarian hormones, many of whose neuroprotective effects converge upon mitochondria. The functional integrity of mitochondria is dependent on membrane fatty acid and phospholipid composition, which are also affected during aging. The effect of long-term ovarian hormone deprivation upon mitochondrial function and its putative association with changes in mitochondrial membrane lipid profile in the hippocampus, an area primarily affected during aging and highly responsive to ovarian hormones, is unknown. To this aim, Wistar adult female rats were ovariectomized or sham-operated. Twelve weeks later, different parameters of mitochondrial function (O2 uptake, ATP production, membrane potential and respiratory complex activities) as well as membrane phospholipid content and composition were evaluated in hippocampal mitochondria. Chronic ovariectomy reduced mitochondrial O2 uptake and ATP production rates and induced membrane depolarization during active respiration without altering the activity of respiratory complexes. Mitochondrial membrane lipid profile showed no changes in cholesterol levels but higher levels of unsaturated fatty acids and a higher peroxidizability index in mitochondria from ovariectomized rats. Interestingly, ovariectomy also reduced cardiolipin content and altered cardiolipin fatty acid profile leading to a lower peroxidizability index. In conclusion, chronic ovarian hormone deprivation induces mitochondrial dysfunction and changes in the mitochondrial membrane lipid profile comparable to an aging phenotype. Our study provides insights into ovarian hormone loss-induced early lipidomic changes with bioenergetic deficits in the hippocampus that may contribute to the increased risk of Alzheimer’s disease and other age-associated disorders observed in postmenopause.Fil: Zarate, Sandra Cristina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Astiz, Mariana. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - La Plata. Instituto de Investigaciones BioquÃmicas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias Médicas. Instituto de Investigaciones BioquÃmicas de La Plata ; ArgentinaFil: Magnani, Natalia Daniela. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de BioquÃmica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de BioquÃmica y Medicina Molecular; ArgentinaFil: Imsen, Mercedes. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Merino, Florencia. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Alvarez, Silvia. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de BioquÃmica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de BioquÃmica y Medicina Molecular; ArgentinaFil: Reines, Analia Gabriela. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de BiologÃa Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de BiologÃa Celular y Neurociencia; ArgentinaFil: Seilicovich, Adriana. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; Argentin
Inhibitory pathways and the inhibition of luteinizing hormone-releasing hormone release by alcohol
Humanin, a mitochondrial-derived peptide released by astrocytes, prevents synapse loss in hippocampal neurons
Astroglial cells are crucial for central nervous system (CNS) homeostasis. They undergo complex morpho-functional changes during aging and in response to hormonal milieu. Ovarian hormones positively affect different astroglia parameters, including regulation of cell morphology and release of neurotrophic and neuroprotective factors. Thus, ovarian hormone loss during menopause has profound impact in astroglial pathophysilogy and has been widely associated to the process of brain aging. Humanin (HN) is a secreted mitochondrial-encoded peptide with neuroprotective effects. It is localized in several tissues with high metabolic rate and its expression decreases with age. In the brain, humanin has been found in glial cells in physiological conditions. We previously reported that surgical menopause induces hippocampal mitochondrial dysfunction that mimics an aging phenotype. However, the effect of ovarian hormone deprivation on humanin expression in this area has not been studied. Also, whether astrocytes express and release humanin and the regulation of such processes by ovarian hormones remain elusive. Although humanin has also proven to be beneficial in ameliorating cognitive impairment induced by different insults, its putative actions on structural synaptic plasticity have not been fully addressed. In a model of surgical menopause in rats, we studied hippocampal humanin expression and localization by real-time quantitative polymerase chain reaction (RT-qPCR) and double immunohistochemistry, respectively. Humanin production and release and ovarian hormone regulation of such processes were studied in cultured astrocytes by flow cytometry and ELISA, respectively. Humanin effects on glutamate-induced structural synaptic alterations were determined in primary cultures of hippocampal neurons by immunocytochemistry. Humanin expression was lower in the hippocampus of ovariectomized rats and its immunoreactivity colocalized with astroglial markers. Chronic ovariectomy also promoted the presence of less complex astrocytes in this area. Ovarian hormones increased humanin intracellular content and release by cultured astrocytes. Humanin prevented glutamate-induced dendritic atrophy and reduction in puncta number and total puncta area for pre-synaptic marker synaptophysin in cultured hippocampal neurons. In conclusion, astroglial functional and morphological alterations induced by chronic ovariectomy resemble an aging phenotype and could affect astroglial support to neuronal function by altering synaptic connectivity and functionality. Reduced astroglial-derived humanin may represent an underlying mechanism for synaptic dysfunction and cognitive decline after menopause.Fil: Zarate, Sandra Cristina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; Argentina. Universidad de Buenos Aires.Facultad de Medicina. Departamento de HistologÃa, EmbriologÃa, BiologÃa Celular y Genética; ArgentinaFil: Traetta, Marianela Evelyn. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de BiologÃa Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de BiologÃa Celular y Neurociencia; ArgentinaFil: Codagnone, MartÃn Gabriel. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de BiologÃa Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de BiologÃa Celular y Neurociencia; ArgentinaFil: Seilicovich, Adriana. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; Argentina. Universidad de Buenos Aires.Facultad de Medicina. Departamento de HistologÃa, EmbriologÃa, BiologÃa Celular y Genética; ArgentinaFil: Reines, Analia Gabriela. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de BiologÃa Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de BiologÃa Celular y Neurociencia; Argentin
Dopamine-Induced Apoptosis of Lactotropes Is Mediated by the Short Isoform of D2 Receptor
Dopamine, through D2 receptor (D2R), is the major regulator of lactotrope function in the anterior pituitary gland. Both D2R isoforms, long (D2L) and short (D2S), are expressed in lactotropes. Although both isoforms can transduce dopamine signal, they differ in the mechanism that leads to cell response. The administration of D2R agonists, such as cabergoline, is the main pharmacological treatment for prolactinomas, but resistance to these drugs exists, which has been associated with alterations in D2R expression. We previously reported that dopamine and cabergoline induce apoptosis of lactotropes in primary culture in an estrogen-dependent manner. In this study we used an in vivo model to confirm the permissive action of estradiol in the apoptosis of anterior pituitary cells induced by D2R agonists. Administration of cabergoline to female rats induced apoptosis, measured by Annexin-V staining, in anterior pituitary gland from estradiol-treated rats but not from ovariectomized rats. To evaluate the participation of D2R isoforms in the apoptosis induced by dopamine we used lactotrope-derived PR1 cells stably transfected with expression vectors encoding D2L or D2S receptors. In the presence of estradiol, dopamine induced apoptosis, determined by ELISA and TUNEL assay, only in PR1-D2S cells. To study the role of p38 MAPK in apoptosis induced by D2R activation, anterior pituitary cells from primary culture or PR1-D2S were incubated with an inhibitor of the p38 MAPK pathway (SB203850). SB203580 blocked the apoptotic effect of D2R activation in lactotropes from primary cultures and PR1-D2S cells. Dopamine also induced p38 MAPK phosphorylation, determined by western blot, in PR1-D2S cells and estradiol enhanced this effect. These data suggest that, in the presence of estradiol, D2R agonists induce apoptosis of lactotropes by their interaction with D2S receptors and that p38 MAPK is involved in this process
Prolactin and its receptor as therapeutic targets in glioblastoma multiforme
Although prolactin (PRL) and its receptor (PRLR) have been detected in glioblastoma multiforme (GBM), their role in its pathogenesis remains unclear. Our aim was to explore their contribution in GBM pathogenesis. We detected PRL and PRLR in all GBM cell lines tested. PRLR activation or overexpression using plasmid transfection increased proliferation, viability, clonogenicity, chemoresistance and matrix metalloproteinase activity in GBM cells, while PRLR antagonist ∆1–9-G129R-hPRL reduced their proliferation, viability, chemoresistance and migration. Meta-analysis of transcriptomic data indicated that PRLR was expressed in all grade II-III glioma (GII-III) and GBM samples. PRL was upregulated in GBM biopsies when compared to GII-III. While in the general population tumour PRL/PRLR expression did not correlate with patient survival, biological sex-stratified analyses revealed that male patients with PRL+/PRLRHIGH GBM performed worse than PRL+/PRLRLOW GBM. In contrast, all male PRL+/PRLRHIGH GII-III patients were alive whereas only 30% of PRL+/PRLRLOW GII-III patients survived after 100 months. Our study suggests that PRLR may be involved in GBM pathogenesis and could constitute a therapeutic target for its treatment. Our findings also support the notion that sexual dimorphism should be taken into account to improve the care of GBM patients.Fil: Asad, Antonela SofÃa. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Nicola Candia, Alejandro Javier. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: González, Nazareno. Laboratorio Max Planck de BiologÃa Estructural, QuÃmica y BiofÃsica Molecular de Rosario; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Zuccato, Camila Florencia. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Abt, Araceli. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Orrillo, Santiago Jordi. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Yael, Lastra. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Cátedra de FisiologÃa Animal; ArgentinaFil: de Simone, Emilio Adrian. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Cátedra de FisiologÃa Animal; ArgentinaFil: Boutillon, Florence. Inserm; FranciaFil: Goffin, Vincent. Inserm; FranciaFil: Seilicovich, Adriana. Universidad de Buenos Aires. Facultad de Medicina. Departamento de BiologÃa Celular e HistologÃa; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Pisera, Daniel Alberto. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Ferraris, Maria Jimena. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Candolfi, Marianela. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; Argentin
The effect of anandamide on prolactin secretion is modulated by estrogen
Recent research has revealed that endogenous cannabinoid receptors (CB1 and CB2) react with the active ingredient of marijuana, Δ9-tetrahydrocannabinol. Two endogenous ligands activate these receptors. The principal one, anandamide (AEA), activates CB1. AEA and CB1 are localized to various neurons within the brain. Because Δ9-tetrahydrocannabinol inhibited prolactin (Prl) secretion following its intraventricular injection into male rats, we hypothesized that AEA would have a similar effect. Estrogen modifies many hormonal responses and is known to increase Prl secretion. Therefore, we hypothesized that responses to intraventricular AEA would change depending on the gonadal steroid environment. Consequently, we evaluated the effects of lateral cerebral ventricular microinjection of AEA (20 ng) into male, ovariectomized (OVX), and estrogen-primed (OVX-E) rats. AEA decreased plasma Prl in male rats, had little effect in OVX females, and increased Prl in OVX-E rats. The results were at least partially mediated by changes in dopaminergic turnover, altering the inhibitory dopaminergic control of Prl release by the anterior pituitary gland. Thus, dopamine turnover was increased in the male rats and decreased significantly in OVX and in OVX-E rats. The changes in Prl may be caused not only by altered dopamine input to the anterior pituitary gland but also by effects of AEA on other transmitters known to alter Prl release. Importantly, in OVX-E rats, the elevated Prl release and the response to AEA were blocked by the AEA antagonist, indicating that AEA is a synaptic transmitter released from neurons that decrease inhibitory control of Prl release.Fil: Scorticati, Camila. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Mohn, Claudia Ester. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: de Laurentiis, Andrea. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Vissio, Paula Gabriela. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Fernández Solari, José Javier. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Seilicovich, Adriana. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: McCann, Samuel M.. Pennington Biomedical Research Center; Estados UnidosFil: Rettori, Valeria. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; Argentin
Prolactin induces apoptosis of lactotropes in female rodents
Anterior pituitary cell turnover occurring during female sexual cycle is a poorly understood process that involves complex regulation of cell proliferation and apoptosis by multiple hormones. In rats, the prolactin (PRL) surge that occurs at proestrus coincides with the highest apoptotic rate. Since anterior pituitary cells express the prolactin receptor (PRLR), we aimed to address the actual role of PRL in the regulation of pituitary cell turnover in cycling females. We showed that acute hyperprolactinemia induced in ovariectomized rats using PRL injection or dopamine antagonist treatment rapidly increased apoptosis and decreased proliferation specifically of PRL producing cells (lactotropes), suggesting a direct regulation of these cell responses by PRL. To demonstrate that apoptosis naturally occurring at proestrus was regulated by transient elevation of endogenous PRL levels, we used PRLR-deficient female mice (PRLRKO) in which PRL signaling is totally abolished. According to our hypothesis, no increase in lactotrope apoptotic rate was observed at proestrus, which likely contributes to pituitary tumorigenesis observed in these animals. To decipher the molecular mechanisms underlying PRL effects, we explored the isoform-specific pattern of PRLR expression in cycling wild type females. This analysis revealed dramatic changes of long versus short PRLR ratio during the estrous cycle, which is particularly relevant since these isoforms exhibit distinct signaling properties. This pattern was markedly altered in a model of chronic PRLR signaling blockade involving transgenic mice expressing a pure PRLR antagonist (TGΔ1–9-G129R-hPRL), providing evidence that PRL regulates the expression of its own receptor in an isoform-specific manner. Taken together, these results demonstrate that i) the PRL surge occurring during proestrus is a major proapoptotic signal for lactotropes, and ii) partial or total deficiencies in PRLR signaling in the anterior pituitary may result in pituitary hyperplasia and eventual prolactinoma development, as observed in TGΔ1–9-G129R-hPRL and PRLRKO mice, respectively.Fil: Ferraris, Maria Jimena. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas; Argentina; Argentina. Universidad de Buenos Aires; ArgentinaFil: Zarate, Sandra Cristina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas; Argentina; Argentina. Universidad de Buenos Aires; ArgentinaFil: Jaita, Gabriela Alejandra. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas; Argentina; Argentina. Universidad de Buenos Aires; ArgentinaFil: Boutillon, Florencia. Universite Paris Sud; FranciaFil: Bernadet, Marie. Universite Paris Descartes; FranciaFil: Auffret, Julien. Universite Paris Sud; FranciaFil: Seilicovich, Adriana. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas; Argentina; Argentina. Universidad de Buenos Aires; ArgentinaFil: Binart, Nadine. Universite Paris Sud; FranciaFil: Goffin, Vincent. Universite Paris Descartes; FranciaFil: Pisera, Daniel Alberto. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas; Argentina; Argentina. Universidad de Buenos Aires; Argentin
Humanin, a Mitochondrial-Derived Peptide Released by Astrocytes, Prevents Synapse Loss in Hippocampal Neurons
Astroglial cells are crucial for central nervous system (CNS) homeostasis. They undergo complex morpho-functional changes during aging and in response to hormonal milieu. Ovarian hormones positively affect different astroglia parameters, including regulation of cell morphology and release of neurotrophic and neuroprotective factors. Thus, ovarian hormone loss during menopause has profound impact in astroglial pathophysilogy and has been widely associated to the process of brain aging. Humanin (HN) is a secreted mitochondrial-encoded peptide with neuroprotective effects. It is localized in several tissues with high metabolic rate and its expression decreases with age. In the brain, humanin has been found in glial cells in physiological conditions. We previously reported that surgical menopause induces hippocampal mitochondrial dysfunction that mimics an aging phenotype. However, the effect of ovarian hormone deprivation on humanin expression in this area has not been studied. Also, whether astrocytes express and release humanin and the regulation of such processes by ovarian hormones remain elusive. Although humanin has also proven to be beneficial in ameliorating cognitive impairment induced by different insults, its putative actions on structural synaptic plasticity have not been fully addressed. In a model of surgical menopause in rats, we studied hippocampal humanin expression and localization by real-time quantitative polymerase chain reaction (RT-qPCR) and double immunohistochemistry, respectively. Humanin production and release and ovarian hormone regulation of such processes were studied in cultured astrocytes by flow cytometry and ELISA, respectively. Humanin effects on glutamate-induced structural synaptic alterations were determined in primary cultures of hippocampal neurons by immunocytochemistry. Humanin expression was lower in the hippocampus of ovariectomized rats and its immunoreactivity colocalized with astroglial markers. Chronic ovariectomy also promoted the presence of less complex astrocytes in this area. Ovarian hormones increased humanin intracellular content and release by cultured astrocytes. Humanin prevented glutamate-induced dendritic atrophy and reduction in puncta number and total puncta area for pre-synaptic marker synaptophysin in cultured hippocampal neurons. In conclusion, astroglial functional and morphological alterations induced by chronic ovariectomy resemble an aging phenotype and could affect astroglial support to neuronal function by altering synaptic connectivity and functionality. Reduced astroglial-derived humanin may represent an underlying mechanism for synaptic dysfunction and cognitive decline after menopause
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