title: Amyotrophic lateral sclerosis immunoglobulins G enhance the mobility of Lysotracker-labelled vesicles in cultured rat astrocytes.
abstract: OBJECTIVE
  We examined the effect of purified immunoglobulins G (IgG) from patients with amyotrophic lateral sclerosis (ALS) on the mobility and exocytotic release from Lysotracker-stained vesicles in cultured rat astrocytes.
  
  
  METHODS
  Time-lapse confocal images were acquired, and vesicle mobility was analysed before and after the application of ALS IgG. The vesicle counts were obtained to assess cargo exocytosis from stained organelles.
  
  
  RESULTS
  At rest, when mobility was monitored for 2 min in bath with Ca(2+), two vesicle populations were discovered: (1) non-mobile vesicles (6.1%) with total track length (TL) < 1 μm, averaging at 0.33 ± 0.01 μm (n = 1305) and (2) mobile vesicles (93.9%) with TL > 1 μm, averaging at 3.03 ± 0.01 μm (n = 20,200). ALS IgG (0.1 mg mL(-1)) from 12 of 13 patients increased the TL of mobile vesicles by approx. 24% and maximal displacement (MD) by approx. 26% within 4 min, while the IgG from control group did not alter the vesicle mobility. The mobility enhancement by ALS IgG was reduced in extracellular solution devoid of Ca(2+), indicating that ALS IgG vesicle mobility enhancement involves changes in Ca(2+) homeostasis. To examine whether enhanced mobility relates to elevated Ca(2+) activity, cells were stimulated by 1 mm ATP, a cytosolic Ca(2+) increasing agent, in the presence (2 mm) and in the absence of extracellular Ca(2+). ATP stimulation triggered an increase in TL by approx. 7% and 12% and a decrease in MD by approx. 11% and 1%, within 4 min respectively. Interestingly, none of the stimuli triggered the release of vesicle cargo.
  
  
  CONCLUSIONS
  Amyotrophic lateral sclerosis-IgG-enhanced vesicle mobility in astrocytes engages changes in calcium homeostasis.
authors: Laboratory of Neuroendocrinology-Molecular Cell Physiology, Medical Faculty, Institute of Pathophysiology, University of Ljubljana, Slovenia.
authors: M
authors: M
authors: Stenovec
authors: M
authors: M
authors: Milošević
authors: V
authors: V
authors: Petrušić
authors: M
authors: M
authors: Potokar
authors: Z
authors: Z
authors: Stević
authors: M
authors: M
authors: Prebil
authors: M
authors: M
authors: Kreft
authors: S
authors: S
authors: Trkov
authors: P R
authors: PR
authors: Andjus
authors: R
authors: R
authors: Zorec
mesh_terms: D000588:Amines; D000690:Amyotrophic Lateral Sclerosis / Q000276:immunology* / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000502:physiology*; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D005089:Exocytosis; D006706:Homeostasis; D006801:Humans; D007074:Immunoglobulin G / Q000502:physiology*; D008247:Lysosomes / Q000502:physiology; D008875:Middle Aged; D051381:Rats; D022161:Transport Vesicles / Q000502:physiology
chemical_list: D000588:Amines; D007074:Immunoglobulin G; C493330:Red DND-99; D002118:Calcium