Constitutive expression of beta-N-acetylhexosaminidase in a microglial cell line: transcriptional modulation by lipopolysaccharide and serum factors.
We investigated the expression of the alpha- and beta-subunits of the lysosomal enzyme beta-N-acetylhexosaminidase in the BV-2 microglial cell line under different culture conditions. Beta-N-acetylhexosaminidase from BV-2 microglia cells was separated into its constituent isoenzymes on diethylaminoethyl (DEAE) cellulose, and its activity was monitored with 4-methylumbelliferyl-beta-N-acetylglucosamine and 4-methylumbelliferyl-beta-N-acetylglucosamine-6-sulphate substrates. Forms corresponding to the mouse isoenzymes A and B were present in the cells incubated in serum-supplemented medium as well as in serum-free medium. Lipopolysaccharide, a well-known activator of microglia in vitro, added to the BV-2 cells in serum-supplemented medium induced a decrease in the specific enzymatic activity determined with the 4-methylumbelliferyl-beta-N-acetylglucosamine substrate. Lipopolysaccharide had no effect on hexosaminidase isoenzyme pattern of BV-2 cells in serum-supplemented medium. The level of alpha-subunit mRNA was increased and the level of beta-subunit mRNA was decreased in BV-2 cells incubated in serum-supplemented medium plus lipopolysaccharide. In the cells incubated in a serum-free medium no significant changes in the hexosaminidase-specific activities towards the above substrates were observed. Interestingly, increased expression of alpha- and beta-subunit mRNA was evident in comparison with cultures in serum-supplemented medium. The present results suggest that the BV-2 cell line may be a useful tool to study the possible role of microglia in the metabolism of brain glycolipids.
Beccari
T
T
Dipartimento di Biologia Cellulare e Molecolare, Università degli Studi di Perugia, Italy.
Orlacchio
A
A
Costanzi
E
E
Grazia Appolloni
M
M
Laurenzi
A
A
Bocchini
V
V
D000818:Animals; D001798:Blood Proteins / Q000494:pharmacology*; D015152:Blotting, Northern; D002460:Cell Line; D048429:Cell Size; D003636:DEAE-Cellulose / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology; D008070:Lipopolysaccharides / Q000494:pharmacology*; D051379:Mice; D017628:Microglia / Q000166:cytology / Q000201:enzymology*; D012333:RNA, Messenger / Q000032:analysis; D014158:Transcription, Genetic / Q000502:physiology; D001619:beta-N-Acetylhexosaminidases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
D001798:Blood Proteins; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D003636:DEAE-Cellulose; D001619:beta-N-Acetylhexosaminidases