A Peri1. 1. Endocrine Unit, Department of Experimental and Biomedical Sciences "Mario Serio", Center for Research, Transfer and High Education on Chronic, Inflammatory, Degenerative and Neoplastic Disorders for the Development of Novel Therapies, University of Florence, Viale Pieraccini, 6, 50139, Florence, Italy. alessandro.peri@unifi.it.
Abstract
INTRODUCTION: Experimental and clinical evidence suggests that estrogens have protective effects in the brain. Nevertheless, their potential role against neurodegenerative diseases, in particular Alzheimer's disease (AD), is still a matter of debate. The identification of the seladin-1 gene (for SELective Alzheimer's Disease INdicator-1), which appeared to be significantly less expressed in brain region affected in AD, opened a new scenario in the field of neuroprotective mechanisms. Seladin-1 was found to have neuroprotective properties through its anti-apoptotic activity. In addition, it was subsequently demonstrated that seladin-1 also has enzymatic activity, because it catalyzes the conversion of desmosterol into cholesterol. Several studies have shown that an appropriate amount of membrane cholesterol plays a pivotal role to protect nerve cells against β-amyloid toxicity in AD and to counteract the synthesis of β-amyloid. METHODS AND RESULTS: We demonstrated that the expression of seladin-1, as well as the synthesis of cell cholesterol, is stimulated by estrogens in human neuronal precursor cells. Cholesterol enriched cells became more resistant against oxidative stress and β-amyloid toxicity. We thus hypothesized that seladin-1 might be a mediator of the neuroprotective effects of estrogens. Indeed, in cells in which seladin-1 gene expression had been silenced by siRNA the protective effects of estrogens were lost. This finding indicates that seladin-1 is a crucial mediator of the neuroprotective effects of these hormones, at least in our cell model. CONCLUSIONS: In summary, these results establish a new link between estrogens and cholesterol, which is represented by the neuroprotective factor seladin-1.
INTRODUCTION: Experimental and clinical evidence suggests that estrogens have protective effects in the brain. Nevertheless, their potential role against neurodegenerative diseases, in particular Alzheimer's disease (AD), is still a matter of debate. The identification of the seladin-1 gene (for SELective Alzheimer's Disease INdicator-1), which appeared to be significantly less expressed in brain region affected in AD, opened a new scenario in the field of neuroprotective mechanisms. Seladin-1 was found to have neuroprotective properties through its anti-apoptotic activity. In addition, it was subsequently demonstrated that seladin-1 also has enzymatic activity, because it catalyzes the conversion of desmosterol into cholesterol. Several studies have shown that an appropriate amount of membrane cholesterol plays a pivotal role to protect nerve cells against β-amyloid toxicity in AD and to counteract the synthesis of β-amyloid. METHODS AND RESULTS: We demonstrated that the expression of seladin-1, as well as the synthesis of cell cholesterol, is stimulated by estrogens in human neuronal precursor cells. Cholesterol enriched cells became more resistant against oxidative stress and β-amyloid toxicity. We thus hypothesized that seladin-1 might be a mediator of the neuroprotective effects of estrogens. Indeed, in cells in which seladin-1 gene expression had been silenced by siRNA the protective effects of estrogens were lost. This finding indicates that seladin-1 is a crucial mediator of the neuroprotective effects of these hormones, at least in our cell model. CONCLUSIONS: In summary, these results establish a new link between estrogens and cholesterol, which is represented by the neuroprotective factor seladin-1.
Authors: A Wechsler; A Brafman; M Shafir; M Heverin; H Gottlieb; G Damari; S Gozlan-Kelner; I Spivak; O Moshkin; E Fridman; Y Becker; R Skaliter; P Einat; A Faerman; I Björkhem; E Feinstein Journal: Science Date: 2003-12-19 Impact factor: 47.728
Authors: G B Vannelli; F Ensoli; R Zonefrati; Y Kubota; A Arcangeli; A Becchetti; G Camici; T Barni; C J Thiele; G C Balboni Journal: J Neurosci Date: 1995-06 Impact factor: 6.167
Authors: D Sarkar; T Imai; F Kambe; A Shibata; S Ohmori; A Siddiq; S Hayasaka; H Funahashi; H Seo Journal: J Clin Endocrinol Metab Date: 2001-11 Impact factor: 5.958