These data suggested that exogenous administration of CGS21680 could prevent early events associated with the induction of EAMG, for example, events linked to the T-cell compartment (Ag recognition, epitope spreading, and T-cell expansion) []. However, in established EAMG, once damage to the neuromuscular junction occurred as a consequence of auto-immune memory,
T- and B-cell responses (in combination with complement activation) directed against the AChR, treatment with CGS21680 was much Dasatinib price less effective. A2AR, similar to other Gs-protein-coupled receptors, signals mainly via the adenylate cyclase–cAMP–PKA canonical pathway []. Recent data have further explained how the A2AR-mediated increase of cAMP may inhibit general T-cell responses such as proliferation [] and cytokine production [[28, 33]]. Therefore the PKA inhibitor (H-89) was included in this assay to verify whether suppression of inflammation mediated by A2AR depended on the cAMP pathway. Furthermore, whether
A2AR-mediated inhibition occurred only during the presence of the A2AR agonist or GDC-0449 mouse if it conferred a permanent alteration to T-cell function was also examined. These results provided evidence that A2AR agonists persistently inhibited the production of anti-AChR IgG antibodies mediated partly as a result of the inhibition of PKA activation (Fig. 4). We next determined the nature of the B cells or CD4+ T cells impacted by CGS21680. First, both proliferation and anti-AChR IgG secretion by B cells was assessed, demonstrating that CGS21680 neither altered the anti-AChR IgG secretion profile nor interfered with B-cell proliferation (Fig. 5). These results were similar to previously published reports [] that demonstrated that B cells responded poorly to A2AR stimulation (determined mafosfamide by measuring cAMP levels in CD4+ T cells, CD8+ T, cells and B cells) following incubation with an A2AR agonist. This led us next to focus on the effect of CGS21680 on CD4+ T-cell function. Although the symptoms
of MG and EAMG are the result of auto-antibodies, CD4+ T cells specific for the target antigen (along with the cytokines secreted) have an important role in the disease development and progression. CD4+ T cells play a role in pathogenesis by driving the synthesis of high-affinity anti-AChR antibodies, as well as secreting proinflammatory cytokines [[6, 8, 9]]. Binding of those antibody subclasses to AChR at the neuromuscular junction triggers complement-mediated destruction of the postsynaptic membrane []. Here, we demonstrated that the number of Th1 cells and Th2 cells were decreased following A2AR activation (Fig. 6 and 9). This result challenged the hypothesis that lymphocyte-expressed A2AR might shift the Th-cell responses from a Th1 toward a Th2 response.