title: Immunoglobulins G from patients with sporadic amyotrophic lateral sclerosis affects cytosolic Ca2+ homeostasis in cultured rat astrocytes.
abstract: Astrocytes are considered essential in the etiopathogenesis of amyotrophic lateral sclerosis (ALS). We have demonstrated previously that immunoglobulins G (IgG) isolated from patients with ALS enhance the mobility of acidic vesicles in cultured astrocytes in a Ca(2+)-dependent manner. Here we directly examined the impact of purified sporadic ALS IgG on cytosolic [Ca(2+)] ([Ca(2+)]i) in astrocytes. Confocal time-lapse images were acquired and fluorescence of a non-ratiometric Ca(2+) indicator was recorded before and after the application of IgG. ALS IgG (0.1 mg/ml) from 7 patients evoked transient increases in [Ca(2+)]i in ~50% of tested astrocytes. The probability of observing a response was independent of extracellular Ca(2+). The peak increase in [Ca(2+)]i developed ~3 times faster and the time integral of evoked transients was ~2-fold larger; the peak amplitude itself was not affected by extracellular Ca(2+). Application of pharmacological inhibitors revealed that activation of inositol-1,4,5-triphosphate receptors is necessary and sufficient to initiate transients in [Ca(2+)]i; the Ca(2+) influx through store-operated calcium entry prolongs the transient increase in [Ca(2+)]i. Thus, ALS IgG acutely affect [Ca(2+)]i by mobilizing both, intra- and extracellular Ca(2+) into the cytosol of cultured astrocytes.
authors.affiliation: University of Ljubljana, Medical Faculty, Institute of Pathophysiology, Laboratory of Neuroendocrinology-Molecular Cell Physiology, Zaloška cesta 4, 1000 Ljubljana, Slovenia.
authors.forename: Milena
authors.initials: M
authors.lastname: Milošević
authors.forename: Matjaž
authors.initials: M
authors.lastname: Stenovec
authors.forename: Marko
authors.initials: M
authors.lastname: Kreft
authors.forename: Vladimir
authors.initials: V
authors.lastname: Petrušić
authors.forename: Zorica
authors.initials: Z
authors.lastname: Stević
authors.forename: Saša
authors.initials: S
authors.lastname: Trkov
authors.forename: Pavle R
authors.initials: PR
authors.lastname: Andjus
authors.forename: Robert
authors.initials: R
authors.lastname: Zorec
mesh_terms: D000690:Amyotrophic Lateral Sclerosis / Q000276:immunology*; D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism*; D005260:Female; D006706:Homeostasis / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D007074:Immunoglobulin G / Q000494:pharmacology*; D066298:In Vitro Techniques; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000502:physiology; D008297:Male; D008875:Middle Aged; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology
chemical_list: D007074:Immunoglobulin G; D053496:Inositol 1,4,5-Trisphosphate Receptors; D002118:Calcium