Electron microscopy (EM) Dissociated cells in the plating medium were seeded into Metrigel Matrix Cell Culture Inserts (BD Biosciences, Bedford, MA, USA), at the same density as that on cover slips. After overnight incubation, the plating medium was replaced with myelination medium (being careful not to disturb cells). Medium change schedule was the same as those in cover slips. At DIV40, cells were fixed with 0.5% glutaraldehyde for 30 min at RT, washed and stored in PBS at 4°C, and then with standard procedures of EM osmication with en bloc, staining of 2% uranyl acetate for 5 min. The tissue was embedded in Durcupan and ultrathin sections were cut and then

examined with a LEO Biological transmission Inhibitors,research,lifescience,medical electron microscope (Zeiss Corp., Thornwood, NY, USA) equipped with digital camera system for later photograph analysis. Treatment with proinflammatory cytokines At DIV14, the spinal cord derived cells were treated with TNFα (10 ng/mL), IL-1β (10 ng/mL), or the vehicle (1:1000 dilution of PBS in the medium) as the control. The culture medium was exchanged with fresh medium containing TNFα, IL-1β, or Inhibitors,research,lifescience,medical the vehicle every 4 days. At DIV40, cells were fixed with 4% PFA and processed for myelin basic protein (MBP)/phosphorylated neurofilament Inhibitors,research,lifescience,medical H (pNF) double immunostaining. Inducing demyelination Two commonly used

demyelinating reagents were tested on the spinal cord-derived myelination culture at DIV40. For LPC-induced demyelination, cells were treated with LPC (100 μg/mL) or the vehicle (1:1000 dilution of ethanol) serving as the control. Inhibitors,research,lifescience,medical For autoimmune-mediated demyelination study, cells were exposed to anti-MOG antibody at 10 μg/mL (Chemicon, Temecula, CA, USA), normal guinea pig serum (source for complement, 12.5 μl/mL) (Diemel et al. 2004), or anti-MOG antibody plus normal guinea pig serum. Untreated sister cultures were used as the control. After 24, 48, and 96 h, cells were Inhibitors,research,lifescience,medical fixed and processed for MBP/pNF double immunocytochemistry. Quantification of myelination Two different approaches were conducted to quantify myelination in our cell culture models. First, myelin segments were initially counted manually at DIV26. Ten fields (25× objective) were randomly

selected and captured from each cover slip with a fluorescence microscope. The numbers of myelin segments were counted and averaged as one sample. Data were obtained from Isotretinoin three separated primary cultures and four cover slips were included in each preparation. Thus, 12 individual samples were obtained for final data analysis. Second, at DIV40, myelin segments were very dense making it almost impossible to individually count the segments. Therefore, an alternative STAT inhibitor approach was adopted by calculating the ratio of areas occupied by myelinated axons (MBP labeled) to the total area of entire image using ImageJ software (see results). The ratio was defined as myelination index (%). Statistics Statistics were performed using SigmaPlot software (version 11.0).