S100B expression in and effects on microglia.
We evaluated the intracellular and extracellular biological role of S100B protein with respect to microglia. S100B, which belongs to the multigenic family of Ca2+-binding proteins, is abundant in astrocytes where it is found diffusely in the cytoplasm and is associated with membranes and cytoskeleton constituents. S100B protein is also secreted by astrocytes and acts on these cells to stimulate nitric oxide secretion in an autocrine manner. However, little is known about the relationship between S100B and microglia. To address this issue, we used primary microglia from newborn rat cortex and the BV-2 microglial cell line, a well-established cell model for the study of microglial properties. S100B expression was assessed by immunofluorescence in primary microglia and by RT-PCR, Western blotting, and immunofluorescence in BV-2 cells. S100B was found in microglia in the form of a filamentous network as well as diffusely in the cytoplasm and associated with intracellular membranes. S100B relocated around phagosomes during BV-2 phagocytosis of opsonized Cryptococcus neoformans. Furthermore, interferon-gamma (IFN-gamma) treatment caused cell shape changes and redistribution of S100B, and downregulation of S100B mRNA expression in BV-2 cells. Treatment of BV-2 cells with nanomolar to micromolar amounts of S100B resulted in increased IFN-gamma-induced expression of inducible nitric oxide synthase mRNA as well as nitric oxide secretion. Taken together, these data suggest a possible role for S100B in the accomplishment/regulation of microglial cell functions.
Adami
C
C
Section of Microbiology, University of Perugia, Via del Giochetto, C.P. 81 Succ. 3, 06122 Perugia, Italy.
Sorci
G
G
Blasi
E
E
Agneletti
A L
AL
Bistoni
F
F
Donato
R
R
D000818:Animals; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D002460:Cell Line / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D020314:Central Nervous System Fungal Infections / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D002540:Cerebral Cortex / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D003455:Cryptococcus neoformans / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects / Q000502:physiology; D005455:Fluorescent Antibody Technique; D007371:Interferon-gamma / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D017628:Microglia / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009414:Nerve Growth Factors / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D010587:Phagocytosis / Q000187:drug effects / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins
D002135:Calcium-Binding Proteins; D009414:Nerve Growth Factors; D012333:RNA, Messenger; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; C579159:S100b protein, mouse; C579158:S100b protein, rat; D009569:Nitric Oxide; D007371:Interferon-gamma; D019001:Nitric Oxide Synthase