Figure 7
Peripheral blood monocytes, but not resident microglia cells, are required for C5a mediated photoreceptor degeneration. (a) C5aR (CD88) and Ly6C expression on CD11b+CD45lo and CD11b+CD45hi cells in the retina following NaIO3 administration. Shaded area indicates isotype control. (b) Flow cytometry following diphtheria toxin (DT) treatment showed no change of circulating Ly6Chi and Ly6Clo monocytes but DT depleted resident retina microglia (left 3 graphs n = 5). Right two graphs show no change in rod or cone photoreceptor loss due to NaIO3 after DT treatment. Naïve = no DT or NaIO3 treatment. Saline = DT treatment with saline control injection, NaIO3 = DT treatment with NaIO3 injection. ##p < 0.01 by Mann-Whitney 2-tailed test and ****p < 0.0001 by 2-way ANOVA with Tukey’s multiple comparisons test. (c) Flow cytometry of circulating Ly6Chi and Ly6Clo monocytes, resident microglia and photoreceptor rods and cones following treatment with PBS- or clodronate-containing liposomes (n = 5). ##p < 0.01 by Mann-Whitney 2-tailed test and *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 by 2-way ANOVA with Tukey’s multiple comparisons test. (d) Flow cytometry of retinal CD11b+CD45hi cells of C57BL/6 J mice treated with PBS or clodronate liposomes, and isotype (Ctrl) or neutralizing a-C5a Abs. (n = 5). (e) SD-OCT analysis of retina loss after NaIO3 administration (n = 5). (f) Flow cytometry of photoreceptor rods and cones (n = 5). Naïve = no NaIO3. *p < 0.05, **p < 0.01, ****p < 0.0001, analyzed by 2-way ANOVA, not including naïve condition. All data were obtained at 3 days after NaIO3 administration. Experiments were repeated at least twice with similar results.
