3C), there was a significant decrease in the percentage of CD11b/CD11c+ DC (Fig. 3D and E). Notably, ER-β ligand treatment did not alter the percentage of CD4+CD25hiFoxp3+ T regulatory cells that could potentially suppress encephalitogenic TC in the CNS (not shown). Naïve mice did not show detectable levels of TC or DC in the CNS. Further analysis
of CD11b/CD11c+ DC in the CNS of EAE mice revealed that ER-β ligand treatment appeared to decrease MHCII expression when compared with vehicle-treated mice, but there were no differences in the level Belnacasan of expression of the costimulatory molecules CD80 and CD86 on DC between treatment groups (Supporting Information Fig. 1). Altogether, these results showed that the cellular composition of CNS inflammation in EAE was affected by ER-β ligand treatment during the effector phase. Specifically, ER-β ligand treatment decreased the percentage of CD11b/CD11c+ DC in the CNS. We next asked whether ER-β ligand treatment might affect cytokine production
by DC in the target organ. We focused on TNF-α because TNF-α is known to mediate demyelination and axonal transection in EAE 24, 25, and we had observed protection of myelin and axons with ER-β ligand treatment (Fig. 2). DC were sorted ex vivo from the CNS of ER-β ligand and vehicle-treated mice at disease onset and TNF-α mRNA Tanespimycin molecular weight levels were quantified by RT-PCR. TNF-α mRNA levels were reduced by 40% in CD11b/CD11c+ DC derived from ER-β ligand-treated EAE mice as compared with vehicle-treated (Fig. 4A). Together, these isothipendyl data showed that in addition to reducing the number of DC in the target organ (Fig. 3), ER-β ligand treatment also reduced their ability to make TNF-α. To further determine whether ER-β ligand treatment in vivo induced functional changes in CNS DC, we performed DC/TC co-cultures. DC were derived from the CNS of ER-β ligand or vehicle-treated EAE mice, whereas autoantigen-primed TC were obtained from LN of untreated mice immunized with autoantigen. Consistent with the previous studies using co-cultures 26, autoantigen stimulation
of co-cultures resulted in proliferation at DC/TC ratios of 1:5 and 1:20, but not at 1:50. Notably, there was no difference in this proliferation when comparing DC derived from ER-β ligand versus vehicle-treated mice (Fig. 4B). However, when TNF-α levels were examined in supernatants, decreased levels of TNF-α were found in cultures that contained DC derived from the CNS of ER-β ligand-treated, as compared with vehicle-treated mice (Fig. 4C). In this experiment, it is possible that the source of TNF-α may be DC and TC. As TNF-α can mediate demyelination and axonal transection in EAE 27, 28, effects on TNF-α production when DC were treated with ER-β ligand were consistent with reduced demyelination and axonal loss in ER-β ligand-treated EAE mice (Fig. 2).