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Mitochondria in activated microglia in vitro.
- Source :
-
Journal of neurocytology [J Neurocytol] 2004 Sep; Vol. 33 (5), pp. 535-41. - Publication Year :
- 2004
-
Abstract
- In the CNS, microglia become activated, i.e. change their functional state and phenotype, in response to a wide variety of pathological stimuli. Since this activation is triggered at a very low threshold and at the same time remains territorially restricted, the spatial distribution of activated microglia can be used as a sensitive, generic measure of the anatomical localisation of ongoing disease processes. One protein complex, undetectable in resting microglia but highly up-regulated upon activation in vivo and in vitro, is the 'peripheral benzodiazepine binding site', as measured by binding of the isoquinoline derivate PK11195. Particularly numerous in the outer membrane of mitochondria, this binding site has also been referred to as the 'mitochondrial benzodiazepine receptor'. The de novo expression of this receptor by activated microglia suggests that the process of activation may be associated with important qualitative changes in the state of mitochondria. Here, we provide confocal light- and electron microscopic evidence that the activation of microglia indeed entails conspicuous mitochondrial alterations. In cultured rat microglia stained with the fluorescent probe, JC-1, a sensitive indicator of mitochondrial membrane potential, we demonstrate that stimulation by bacterial lipopolysaccharide and interferon-gamma increases the number of microglial mitochondrial profiles and leads to marked changes in their morphology. Prominent elongated, "needle-like" mitochondria are a characteristic feature of activated microglia in vitro. Electron microscopically, an abundance of abnormal profiles, including circular cristae or ring- and U-shaped membranes, are found. Our observations support the notion that the previously reported increase in microglial binding of PK11195, that labelled with carbon-11 ([11C] (R)-PK11195) has clinical use for the visualisation of activated microglia in vivo by positron emission tomography, may at least in part relate to an increased number and altered functional state of microglial mitochondria.
- Subjects :
- Animals
Antineoplastic Agents metabolism
Benzimidazoles
Binding Sites drug effects
Binding Sites physiology
Carbocyanines
Carrier Proteins drug effects
Carrier Proteins metabolism
Cell Shape drug effects
Cell Shape physiology
Cells, Cultured
Fluorescent Dyes
Gliosis chemically induced
Gliosis metabolism
Inflammation Mediators pharmacology
Intracellular Membranes metabolism
Intracellular Membranes ultrastructure
Isoquinolines metabolism
Isoquinolines pharmacokinetics
Membrane Potentials drug effects
Membrane Potentials physiology
Microglia drug effects
Microglia metabolism
Microscopy, Confocal
Microscopy, Electron, Transmission
Mitochondria drug effects
Mitochondria metabolism
Rats
Receptors, GABA-A drug effects
Receptors, GABA-A metabolism
Up-Regulation drug effects
Up-Regulation physiology
Gliosis physiopathology
Microglia ultrastructure
Mitochondria ultrastructure
Subjects
Details
- Language :
- English
- ISSN :
- 0300-4864
- Volume :
- 33
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- Journal of neurocytology
- Publication Type :
- Academic Journal
- Accession number :
- 15906160
- Full Text :
- https://doi.org/10.1007/s11068-004-0515-7