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Objective: Myelin is essential for a healthy nervous system. Myelin formed by oligodendrocytes, accelerates impulse propagation and supports neuronal survival. Demyelination leads to neurodegeneration. In multiple sclerosis (MS) immune attack results in demyelination. Our goal is to dissect interactions among oligodendrocytes, neurons, and immune cells to improve our understanding of myelination and the demyelinating diseases. We aim to discover new targets for remyelination therapies. Methods: We are building tools for analyzing protein-protein and cell-to-cell interactions. To identify genes involved in myelination and MS, we developed a bioinformatics-based strategy, interactome analysis, which combines proteome and gene expression methodologies. Identified genes are evaluated in peripheral blood of MS patients and in mouse models. To accelerate drug discovery, 23 machine learning-based methodologies were assessed for myelin identification in fluorescent microscopy images. Results: Interactome analysis identified hundreds of proteinprotein interactions between pairs of oligodendrocytes, neurons, macrophages, microglia, and T cells. Most significant interactions are further analyzed in vivo and in vitro. Our customizedconvolutional neural network and Boosted Tree methods segmented myelin at over 98% accuracy. Identified myelin can be quantified and visualized in 3D. Conclusion: The interactome analysis yielded novel genes that are likely to be linked to MS. Machine learning-based methodologies are very effective in accelerating myelin quantification and thus, drug screens against demyelinating diseases such as MS. Overall, our innovative analysis strategies employing computer assistance produced novel avenues of exploration for myelination and demyelinating diseases. This study was supported TUBITAK (218S495,316S026), Istanbul Medipol University (BAP2018/06), and Turkish Academy of Sciences (GEBIP). [ABSTRACT FROM AUTHOR]

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]

Objective: Function of the myelin membrane is to accelerate impulse propagation and support metabolism and health of an axon that may extend a long distance off the neuronal body. In the central nervous system specialized glia cells -oligodendrocyteswrap the axons. An oligodendrocyte has to generate a striking amount of membrane as it can wrap up to 30-40 internodes, which are myelinated regions between nodes of Ranvier. During the expansion of the oligodendrocyte membrane towards the nodes of Ranvier large amounts of lipid and protein are trafficked to the cell membrane. Thus, defects in the cellular vesicular transport may result in myelin disorders such as "Pelizaeus-Merzbacher" disease (PMD). Cellular transport and the resulting membrane expansion processes were studied in detail at the ultrastructural level mainly by immunocytochemistry and electron microscopy, yet their dynamics are poorly understood during myelination. In order to fill the gap in our understanding, we aim to monitor lipid and protein transport to the cellular membrane in real-time. Methods: Using oligodendrocytes derived from stem cells, the cargo vesicles, lipids and lipid rafts in oligodendrocytes were monitored in real-time during myelin formation using fluorescent dyes and fluorescent proteins. Monitored oligodendrocytes were categorized according to their maturation status. Results: Our early results revealed that membrane lipids and cargo vesicles carrying different proteins followed different transportation patterns and integrated to the membrane at different locations. Conclusion: Higher temporal and spatial resolution observations are needed to reach a more detailed description of molecular physiology of myelination. Increased knowledge on myelination will not only result in a better understanding of the basic biology of the oligodendrocytes but will also improve our understanding of the myelination disorders such as PMD. [ABSTRACT FROM AUTHOR]