Lipopolysaccharide-stimulated interleukin-10 release from neonatal spinal cord microglia is potentiated by glutamate

• Published in: Neuroscience Vol. 175; pp. 93 - 103
• Main Authors: Werry, E.L, Liu, G.J, Lovelace, M.D, Nagarajah, R, Hickie, I.B, Bennett, M.R
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 17-02-2011; Elsevier
• Subjects: Animals; Animals, Newborn; Biological and medical sciences; Cells, Cultured; Culture Media, Conditioned; Drug Synergism; Fundamental and applied biological sciences. Psychology; Glutamic Acid - physiology; inflammation; Inflammation Mediators - metabolism; Inflammation Mediators - physiology; Interleukin-10 - physiology; Interleukin-10 - secretion; Interleukin-1beta - metabolism; lipopolysaccharide; Lipopolysaccharides - physiology; microglia; Microglia - cytology; Microglia - pathology; Microglia - secretion; Neurology; Rats; Rats, Sprague-Dawley; Receptors, Glutamate - physiology; Spinal Cord - cytology; Spinal Cord - pathology; Spinal Cord - secretion; Up-Regulation - physiology; Vertebrates: nervous system and sense organs; Rp-adenosine 3′,5′-cyclic monophosphorothioate triethylammonium salt hydrate; supplemented Dulbecco's modified Eagle's medium; l-AP4; N-methyl- d-aspartate; H-89; 6-cyano-7-nitroquinoxaline-2,3-dione; (2S)-α-ethylglutamic acid; U73122; EGLU; tACPD; kainate; mGluR; Glu; MK-801; RT-PCR; N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide dihydrochloride; glutamate; 1-[6-[((17β)-3-methoxyestra-1,3,5-trien-17-yl)amino]hexyl]-2,5-pyrrolidinedione; CPCCOEt; (+)-5-methyl-10,11-dihydroxy-5h-dibenzo (a,d)cyclohepten-5,10-imine; PKA; lactate dehydrogenase; PKC; MPEP; 1,2-dimethoxy-N-methyl(1,3)benzodioxolo(5,6-c)phenanthridinium chloride; 6-methyl-2-(phenylethynyl)pyridine; IL-10; ( S)-3,5-dihydroxyphenylglycine hydrate; reverse transcriptase-polymerase chain reaction; 7-hydroxyiminocyclopropan[b]chromen-1α-carboxylic acid ethyl ester; MSPG; lipopolysaccharide; TLR4; toll-like receptor 4; ELISA; chelerythrine chloride; metabotropic glutamate receptor; PLC; U73343; CNQX; interleukin-10; LPS; DMEM; LDH; inflammation; Rp-cAMPS; KA; l-(+)-2-amino-4-phosphonobutyric acid; NMDA; 1-[6-[((17β)-3-methoxyestra-1,3,5-trien-17-yl)amino]hexyl]-1H-pyrrole-2,5-dione; DHPG; protein kinase A; microglia; protein kinase C; phospholipase C; (2R,4R)-4-aminopyrrolidine-2,4-dicarboxylate; trans-(1S,3R)-1-amino-1,3-cyclopentanedicarboxylic acid; APDC; 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid tetrakis(acetoxymethyl ester); enzyme-linked immunosorbent assay; (±)-α-methyl-(4-sulfonophenyl)glycine; BAPTA-AM; Spinal cord; Neuroglia; Cytokine; Central nervous system; Interleukin 10; Excitatory aminoacid; Neurotransmitter; Lipopolysaccharide; Inflammation; Glutamate; Release; Microglia
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/j.neuroscience.2010.10.080

Abstract Interleukin-10 (IL-10) is a cytokine with important endogenous and therapeutic anti-inflammatory effects. Given this, it is of interest to investigate factors that modulate IL-10 levels in the central nervous system. IL-10 is released after lipopolysaccharide (LPS) stimulation of microglia. Microglia also express functional glutamate receptors and in inflammatory conditions are exposed to increased levels of glutamate. The aim of this research, then, is to investigate whether glutamate can modulate lipopolysaccharide stimulation of IL-10 release from neonatal rat spinal cord microglia. Enzyme-linked immunosorbent assays (ELISAs) were used to quantify IL-10 release from cultured neonatal spinal cord microglia and reverse transcriptase-polymerase chain reaction (RT-PCR) was used to measure IL-10 mRNA expression. Glutamate (1 mM) significantly increased LPS (1 μg/ml)-stimulated IL-10 release from microglia by 172% (EC50 of 103 μM) and significantly upregulated IL-10 mRNA levels. Glutamate potentiated LPS-stimulated IL-10 release by binding all subtypes of glutamate receptor. These results show that glutamate substantially increases the release of an anti-inflammatory cytokine from neonatal spinal cord microglia activated by a high concentration of LPS.