(A) Repeated FTY720 administrations inhibit IL-1β-induced Ca
mobilization in human fetal astrocytes. Representative traces showing daily FTY720 for 5 days inhibited IL-1β (10 ng/ml)-induced Ca2+ mobilization; this effect was not seen with FTY720 (1× FTY720) or vehicle (1× vehicle) added only at outset of the culture, nor with the vehicle control added daily for 5 days (5× vehicle). (B) Bar graph showing the mean (±SEM) changes in Ca2+ mobilization under conditions described in (A). *Signifies comparison between FTY720 (5×) and vehicle (5×) (n = 3). (C) Pre-treatment of human fetal astrocytes with FTY720 does not alter IL-6 or CXCL10 (IP-10) secretions induced by IL-1β. Astrocytes pre-treated with either FTY720 (F) or with the vehicle (v) control at outset of culture (1×) or daily for three cycles (3×). After the 72-h culture, IL-1β (10 ng/ml) was added and cells were cultured for an additional 24 h before collecting supernatants (n = 3). (i) Astrocytes produced significant levels of IL-6 in response to IL-1β activation. Levels of IL-6 produced were not affected by FTY720 pre-treatment(s), and FTY720 itself did not induce significant IL-6 secretion. (ii) Astrocytes produced significant levels of CXCL10 (IP-10) response to IL-1β activation. Pre-treating astrocytes with FTY720 did not alter CXCL10 secretion induced by IL-1β, and FTY720 itself did not induce CXCL10 secretion (n = 3).