The investigation of effect of macrophages on neural cells of the central nervous system.

Objective: Macrophages have a dual effect on multiple sclerosis (MS) they promote remyelination via secreted factors and they phagocytose myelin causing demyelination. Thus, signaling pathways regulating macrophage physiology are investigated as therapeutic targets. Among those pathways, dopamine and adenosine signaling pathways, drew attention due to positive results in animal models. Additionally, the two pathways were shown to act synergistically in in vitro experiments. Therefore, synergistic modulation of dopamine and adenosine pathways in macrophages may be a key target for MS therapy. Goal of this study is to investigate the effect of modulation of dopamine and adenosine pathways on myelin damage and remyelination using macrophage oligodendrocyte co-cultures. Methods: First, co-cultures were established with inactivated and lipopolysaccharide (LPS)-activated macrophages isolated from adult mice peritoneum and oligodendrocytes differentiated from the cortex of newborn mice. 48-hour old co-cultures were treated with single, double and triple combinations of dopamine signaling pathway agonist (Quinpirole), adenosine signaling pathway agonist (Istradefylline) and antagonist (CGS21680). Then, co-cultures were fixed and analyzed using immunocytochemistry. Macrophages were labeled with CD11b, oligodendrocytes with SOX10 and mature oligodendrocytes with Myelin Basic Protein (MBP) and quantified by cell counting. Results: In co-cultures with inactivated and LPS-activated macrophages, an increase in the number of mature oligodendrocytes was observed while the total number of oligodendrocytes did not change. However, a triple combination of agonists and antagonist treatment reduced number of mature oligodendrocytes in the LPS-activated macrophage-oligodendrocyte co-cultures. Conclusion: Inactive and LPS-activated macrophages increased the number of mature oligodendrocytes under co-culture conditions. Therefore, macrophages have a positive effect on oligodendrocytes when not activated by MS cues or to a similar extend and LPS treatment alone is not enough to simulate MS like conditions. Observed positive effect can be inhibited by modulating dopamine and adenosine signaling pathways. We thank TUBITAK for their support. [ABSTRACT FROM AUTHOR]