Figure 3

Astrocyte-derived galectin-9 promotes microglial TNF production. Mono-, co- or mixed glial cultures obtained from littermate control (Lgals9 ^+/+ or Lgals9 ^+/-) or Lgals9 ^-/- mice were stimulated with poly(I:C) (25 μg/ml) for 24 hours and TNF measured from the supernatants by ELISA. (A-B) Reduction in supernatant levels of TNF obtained from mixed glia (A) despite similar numbers of Iba-1⁺ microglia across genotypes (B). Results in (A) are combined means ± SE of 5 independent experiments (CTL n = 19; Lgals9 ^-/- n = 12); results in (B) are combined means ± SE of glial cultures depicted in (A) chosen at random (Lgals-9 ^+/- n = 3; Lgals9 ^-/- n = 3). Scale bar, 50 μm. (C) TNF levels from poly(I:C) activated astrocyte and microglial monocultures derived from Lgals-9 ^+/+ or Lgals9 ^-/- mice. Results are means ± SE of quadruplicate samples and are representative of two independent experiments. (D) Supernatant levels of TNF following poly(I:C) stimulation of microglial monocultures compared to co-cultures containing Lgals-9 ^+/+ (wild-type (WT); black) or Lgals9 ^-/- (knockout (KO); red) astrocytes. Results are means ± SE of quadruplicate samples and are representative of four independent experiments. *P < 0.05, **P < 0.01, ***P < 0.001.