CONICET | Buscador de Institutos y Recursos Humanos

Astroglial cells are crucial for central nervous system (CNS) homeostasis. They undergocomplex morpho-functional changes during aging and in response to hormonal milieu.Ovarian hormones positively affect different astroglia parameters, including regulation ofcell morphology and release of neurotrophic and neuroprotective factors. Thus, ovarianhormone loss during menopause has profound impact in astroglial pathophysilogy andhas been widely associated to the process of brain aging. Humanin (HN) is a secretedmitochondrial-encoded peptide with neuroprotective effects. It has been localized inseveral tissues with high metabolic rate and its expression decreases with age. In thebrain, humanin has been localized in glial cells in physiological conditions. We previouslyreported that surgical menopause induces hippocampal mitochondrial dysfunction thatmimics an aging phenotype. However, the effect of ovarian hormone deprivation onhumanin expression in this area has not been studied. Also, whether astrocytes expressand release humanin and the regulation of such processes by ovarian hormonesremain elusive. Although humanin has also proven to be beneficial in amelioratingcognitive impairment induced by different insults, its putative actions on structuralsynaptic plasticity have not been fully addressed. In a model of surgical menopausein rats, we studied hippocampal humanin expression and localization by real-timequantitative polymerase chain reaction (RT-qPCR) and double immunohistochemistry,respectively. Humanin production and release and ovarian hormone regulation ofsuch processes were studied in cultured astrocytes by flow cytometry and ELISA,respectively. Humanin effects on glutamate-induced structural synaptic alterations weredetermined in primary cultures of hippocampal neurons by immunocytochemistry.