Abstract
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.
Original language | English |
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Pages (from-to) | 1175-85 |
Number of pages | 11 |
Journal | European Journal of Neuroscience |
Volume | 16 |
Issue number | 7 |
Publication status | Published - Oct 2002 |
Keywords
- Animals
- Animals, Newborn
- Astrocytes
- COS Cells
- Cells, Cultured
- Coculture Techniques
- Comparative Study
- Enzyme-Linked Immunosorbent Assay
- Humans
- Interleukin-1
- Interleukin-10
- Journal Article
- Lipopolysaccharides
- Microglia
- Polymerase Chain Reaction
- RNA, Messenger
- Rats
- Rats, Wistar
- Receptors, Interleukin
- Receptors, Interleukin-10
- Research Support, Non-U.S. Gov't
- Transcription, Genetic
- Transfection