Fig. 5: Decorin inhibits Nf1-OPG formation.

a Decorin (800 pg/ml) attenuated activated TCM (act-Tm)-mediated microglia Ccl5 production (n = 3). Two-tailed Student’s t test. Exact P values are indicated within each panel (ns, not significant). b Decorin reduces microglia Ccl5 production in response to Ccl4 exposure (6 ng/ml) over a physiologic dose range in vitro (n = 4). One-way ANOVA with Bonferroni post hoc correction. Data are presented as the means ± SEM. c TCM (activated T cell-conditioned media) induced microglial Ccl5 production was significantly attenuated by decorin. The addition of Dcn with CCR5 has the greatest inhibition similar to the combination of CCR5 and CCR8 inhibitors (n = 6). One-way ANOVA with Bonferroni post hoc correction. Data are presented as the means ± SEM. d Schematic representation of decorin binding to the CCR8 receptor on microglia, culminating is reduced microglial Ccl5 production by inhibiting NFκB activation. e Schematic representation of decorin treatment of Nf1^OPG mice. Nf1^OPG mice were treated between 4 and 6 weeks of age with decorin, while control Nf1^OPG mice received PBS only. Isolated optic nerves were analyzed at 12 weeks of age. f Decorin treatment has no change on optic nerve volume, but (g) decreased proliferation (%Ki67⁺ cells) of Nf1^OPG mice relative to the vehicle-treated Nf1^OPG controls (PBS, n = 8, Decorin, n = 8). No difference in microglia (%Iba1⁺ cells) or T cell (CD3⁺ cells) content was observed between decorin-treated mice and their respective controls. Two-tailed Student’s t test (ns, not significant). g Scale bars, 40 µm. From left to right in each panel: a P = 0.0134, b P < 0.0001, P = 0.0035; c P < 0.0001, ns, P = 0.0086, ns; f ns; g P = 0.0010, ns, ns.