Author/Editor | Potokar, Maja; Stenovec, Matjaž; Gabrijel, Mateja; Li, Lizhen; Kreft, Marko; Grilc, Sonja; Penky, Miloš; Zorec, Robert | |
Title | Intermediate filaments attenuate stimulation-dependent mobility of endosomes/lysosomes in astrocytes | |
Type | članek | |
Source | Glia | |
Vol. and No. | Letnik 58, št. 10 | |
Publication year | 2010 | |
Volume | str. 1208-19 | |
Language | eng | |
Abstract | Intermediate filament (IF) proteins upregulation is a hallmark of astrocyte activation and reactive gliosis, but its pathophysiological implications remain incompletely understood. A recently reported association between IFs and directional mobility of peptidergic vesicles allows us to hypothesize that IFs affect vesicle dynamics and exocytosis-mediated astrocyte communication with neighboring cells. Here, we ask whether the trafficking of recycling vesicles (i.e., those fused to and then retrieved from the plasma membrane) and endosomes/lysosomes depends on IFs. Recycling vesicles were labeled by antibodies against vesicle glutamate transporter 1 (VGLUT1) and atrial natriuretic peptide (ANP), respectively, and by lysotracker, which labels endosomes/lysosomes. Quantitative fluorescence microscopy was used to monitor the mobility of labeled vesicles in astrocytes, derived from either wild-type (WT) mice or mice deficient in glial fibrillary acidic protein and vimentin (GFAP-/-Vim-/-), the latter lacking astrocyte IFs. Stimulation with ionomycin or ATP enhanced the mobility of VGLUT1-positive vesicles and reduced the mobility of ANP-positive vesicles in WT astrocytes. In GFAP-/-Vim-/- astrocytes, both vesicle types responded to stimulation, but the relative increase in mobility of VGLUT1-positive vesicles was more prominent compared with nonstimulated cells, whereas the stimulation-dependent attenuation of ANP-positive vesicles mobility was reduced compared with nonstimulated cells. The mobility of endosomes/lysosomes decreased following stimulation in WT astrocytes. However, in GFAP-/-Vim-/- astrocytes, a small increase in the mobility of endosomes/lysosomes was observed. These findings show that astrocyte IFs differentially affect the stimulation-dependent mobility of vesicles. We propose that upregulation of IFs in pathologic states may alter the function of astrocytes by deregulating vesicle trafficking. | |
Descriptors | ASTROCYTES ENDOSOMES LYSOSOMES INTERMEDIATE FILAMENT PROTEINS IMMUNOHISTOCHEMISTRY ATRIAL NATRIURETIC FACTOR GLIAL FIBRILLARY ACIDIC PROTEIN VIMENTIN MICROSCOPY, CONFOCAL IONOMYCIN CELLS, CULTURED MICE, INBRED STRAINS |