Expression and regulation of interleukin-10 and interleukin-10 receptor in rat astroglial and microglial cells.
Activated glial cells crucially contribute to brain inflammatory responses. Interleukin-10 (IL-10) is an important modulator of glial cell responses in the brain. In the present study we describe the expression of IL-10 and the IL-10 receptor (IL-10R1) in primary cocultures of rat microglial and astroglial cells. Using quantitative RT-PCR and ELISA, we show that IL-10 mRNA expression and subsequent IL-10 secretion is time-dependently induced by lipopolysaccharide (LPS). IL-10R1, however, is constitutively expressed in glial cell cocultures, as shown by RT-PCR and immunocytochemistry. Radioligand binding studies using 125I-IL-10 reveal that rat glial cells express a single binding site with an apparent affinity of approximately 600 pm for human IL-10. Observations in enriched cultures of either microglial or astroglial cells indicate that both cell types express IL-10 mRNA and are capable of secreting IL-10. Both cell types also express IL-10R1 mRNA and protein. However, in glial cell cocultures immunoreactive IL-10R1 protein is predominantly observed in astrocytes, suggesting that microglial expression of IL-10R1 in cocultures is suppressed by astrocytes. In addition, exogenous IL-10 is highly potent in down-regulating LPS-induced IL-1beta and IL-10 mRNA, and, at a higher dose, IL-10R1 mRNA in untreated and LPS-treated cultures, suggesting that IL-10 autoregulates its expression and inhibits that of IL-1beta at the transcriptional level. Together the findings support the concept that IL-10, produced by activated microglial and astroglial cells, modulates glia-mediated inflammatory responses through high-affinity IL-10 receptors via paracrine and autocrine interactions.
Ledeboer
Annemarie
A
Department of Medical Pharmacology, Research Institute Neurosciences Free University, VUmc, Van der Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands.
Brevé
John J P
JJ
Wierinckx
Anne
A
van der Jagt
Saskia
S
Bristow
Adrian F
AF
Leysen
Josée E
JE
Tilders
Fred J H
FJ
Van Dam
Anne-Marie
AM
D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D019556:COS Cells / Q000378:metabolism; D002478:Cells, Cultured; D018920:Coculture Techniques; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007375:Interleukin-1 / Q000096:biosynthesis / Q000235:genetics; D016753:Interleukin-10 / Q000096:biosynthesis* / Q000235:genetics; D008070:Lipopolysaccharides / Q000494:pharmacology; D017628:Microglia / Q000187:drug effects / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger; D051381:Rats; D017208:Rats, Wistar; D018123:Receptors, Interleukin / Q000096:biosynthesis* / Q000235:genetics; D053701:Receptors, Interleukin-10; D014158:Transcription, Genetic; D014162:Transfection
D007375:Interleukin-1; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D018123:Receptors, Interleukin; D053701:Receptors, Interleukin-10; D016753:Interleukin-10