Effects of cytokines on microglial phenotypes and astroglial coupling in an inflammatory coculture model.
Cytokines play an important role in the onset, regulation, and propagation of immune and inflammatory responses within the central nervous system (CNS). The main source of cytokines in the CNS are microglial cells. Under inflammatory conditions, microglial cells are capable of producing pro- and antiinflammatory cytokines, which convey essential impact on the glial and neuronal environment. One paramount functional feature of astrocytes is their ability to form a functionally coupled syncytium. The structural link, which is responsible for the syncytial behavior of astrocytes, is provided by gap junctions. The present study was performed to evaluate the influence of inflammation related cytokines on an astroglial/microglial inflammatory model. Primary astrocytic cultures of newborn rats were cocultured with either 5% (M5) or 30% (M30) microglial cells and were incubated with the following proinflammatory cytokines: tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), interleukin-6 (IL-6), interferon-gamma (IFN-gamma), and the antiinflammatory cytokines transforming growth factor-beta1 (TGF-beta1) and IFN-beta. Under these conditions, i.e., incubation with the inflammatory cytokines and the high fraction of microglia (M30), microglial cells revealed a significant increase of activated round phagocytotic cells accompanied by a reduction of astroglial connexin 43 (Cx43) expression, a reduced functional coupling together with depolarization of the membrane resting potential (MRP). When the antiinflammatory mediator TGF-beta1 was added to proinflammatory altered M30 cocultures, a reversion of microglial activation and reconstitution of functional coupling together with recovery of the astroglial MRP was achieved. Finally IFN-beta, added to M5 cocultures was able to prevent the effects of the proinflammatory cytokines TNF-alpha, IL-1beta, and IFN-gamma.
Hinkerohe
Daniel
D
Department of Neuroanatomy and Molecular Brain Research, Ruhr University Bochum, Bochum, Germany.
Smikalla
Dirk
D
Haghikia
Aiden
A
Heupel
Katharina
K
Haase
Claus G
CG
Dermietzel
Rolf
R
Faustmann
Pedro M
PM
D000818:Animals; D001253:Astrocytes / Q000187:drug effects* / Q000473:pathology; D002450:Cell Communication / Q000187:drug effects; D018920:Coculture Techniques; D018031:Connexin 43 / Q000502:physiology; D016207:Cytokines / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D004594:Electrophysiology; D005455:Fluorescent Antibody Technique; D006801:Humans; D007249:Inflammation / Q000473:pathology*; D007370:Interferon Type I / Q000494:pharmacology; D008297:Male; D008564:Membrane Potentials / Q000502:physiology; D017628:Microglia / Q000187:drug effects* / Q000473:pathology; D010641:Phenotype; D051381:Rats; D017208:Rats, Wistar; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta / Q000378:metabolism; D053773:Transforming Growth Factor beta1
D018031:Connexin 43; D016207:Cytokines; D007370:Interferon Type I; D011994:Recombinant Proteins; C508960:TGFB1 protein, human; C508962:Tgfb1 protein, rat; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1