title: Expression of familial Alzheimer disease presenilin 1 gene attenuates vesicle traffic and reduces peptide secretion in cultured astrocytes devoid of pathologic tissue environment.
abstract: In the brain, astrocytes provide metabolic and trophic support to neurones. Failure in executing astroglial homeostatic functions may contribute to the initiation and propagation of diseases, including Alzheimer disease (AD), characterized by a progressive loss of neurones over years. Here, we examined whether astrocytes from a mice model of AD isolated in the presymptomatic phase of the disease exhibit alterations in vesicle traffic, vesicular peptide release and purinergic calcium signaling. In cultured astrocytes isolated from a newborn wild-type (wt) and 3xTg-AD mouse, secretory vesicles and acidic endosomes/lysosomes were labeled by transfection with plasmid encoding atrial natriuretic peptide tagged with mutant green fluorescent protein (ANP.emd) and by LysoTracker, respectively. The intracellular Ca(2+) concentration ([Ca(2+)]i) was monitored with Fluo-2 and visualized by confocal microscopy. In comparison with controls, spontaneous mobility of ANP- and LysoTracker-labeled vesicles was diminished in 3xTg-AD astrocytes; the track length (TL), maximal displacement (MD) and directionality index (DI) were all reduced in peptidergic vesicles and in endosomes/lysosomes (P < 0.001), as was the ATP-evoked attenuation of vesicle mobility. Similar impairment of peptidergic vesicle trafficking was observed in wt rat astrocytes transfected to express mutated presenilin 1 (PS1M146V). The ATP-evoked ANP discharge from single vesicles was less efficient in 3xTg-AD and PS1M146V-expressing astrocytes than in respective wt controls (P < 0.05). Purinergic stimulation evoked biphasic and oscillatory [Ca(2+)]i responses; the latter were less frequent (P < 0.001) in 3xTg-AD astrocytes. Expression of PS1M146V in astrocytes impairs vesicle dynamics and reduces evoked secretion of the signaling molecule ANP; both may contribute to the development of AD.
authors.affiliation: Celica BIOMEDICAL, Ljubljana, Slovenia.|Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Matjaž
authors.initials: M
authors.lastname: Stenovec
authors.affiliation: Celica BIOMEDICAL, Ljubljana, Slovenia.|Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Saša
authors.initials: S
authors.lastname: Trkov
authors.affiliation: Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Eva
authors.initials: E
authors.lastname: Lasič
authors.affiliation: Celica BIOMEDICAL, Ljubljana, Slovenia.|Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.|Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.|Department of Neuroscience, Faculty of Medicine and Odontology, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain.
authors.forename: Slavica
authors.initials: S
authors.lastname: Terzieva
authors.affiliation: Celica BIOMEDICAL, Ljubljana, Slovenia.|Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.|Department of Biology, University of Ljubljana, Biotechnical Faculty, CPAE, Ljubljana, Slovenia.
authors.forename: Marko
authors.initials: M
authors.lastname: Kreft
authors.affiliation: Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.|Department of Neuroscience, Faculty of Medicine and Odontology, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain.
authors.forename: José Julio
authors.initials: JJ
authors.lastname: Rodríguez Arellano
authors.affiliation: Department of Neurobiology, Civitan International Research Center and Center for Glial Biology in Medicine, Evelyn F. McKnight Brain Institute, Atomic Force Microscopy & Nanotechnology Laboratories, University of Alabama at Birmingham, Birmingham, Alabama.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Parpura
authors.affiliation: Celica BIOMEDICAL, Ljubljana, Slovenia.|Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.|Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.|Department of Neuroscience, Faculty of Medicine and Odontology, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain.|Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom.
authors.forename: Alexei
authors.initials: A
authors.lastname: Verkhratsky
authors.affiliation: Celica BIOMEDICAL, Ljubljana, Slovenia.|Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Robert
authors.initials: R
authors.lastname: Zorec
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000544:Alzheimer Disease / Q000378:metabolism*; D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D009320:Atrial Natriuretic Factor / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000502:physiology; D002413:Cations, Divalent / Q000378:metabolism; D002478:Cells, Cultured; D004195:Disease Models, Animal; D011992:Endosomes / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008247:Lysosomes / Q000378:metabolism*; D057507:Mice, 129 Strain; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D053764:Presenilin-1 / Q000235:genetics / Q000378:metabolism*; D017208:Rats, Wistar; D022142:Secretory Vesicles / Q000378:metabolism*
chemical_list: D002413:Cations, Divalent; C508853:PSEN1 protein, human; D053764:Presenilin-1; D049452:Green Fluorescent Proteins; D009320:Atrial Natriuretic Factor; D000255:Adenosine Triphosphate; D002118:Calcium
keywords: ANP.emd; LysoTracker; calcium signaling; regulated exocytosis; vesicle mobility