Figure 8.

Autophagy limits apoptotic induction in CHIKV infected tissues and delays lethality of mice. (A–F) WT (n = 43) and Atg16L^HM mice (n = 34) were infected at 9 d of age with 4 × 10⁵ PFU CHIKV subcutaneously. (A) Mice were monitored for lethality for 21 d with data displayed as Kaplan-Meier curves. (B) Skin, muscle, and serum were collected after days 1 (n = 3), 2 (n = 3), 5 (n = 4), and 9 (n = 5) of infection, homogenized, and viral titers were determined by standard plaque assay. Median values for WT (black bars) or Atg16L^HM (blue bars) mice are depicted. (C) Muscle, skin, liver, brain, BM, and spleen were collected from WT infected mice at day 5. Tissues were fixed in PFA, frozen in OCT blocks, and stained for cleaved capsase-3 (green) and E3 (red). Similar results were observed in two independent experiments. Bars: (muscle) 50 µm; (other tissues) 20 µm. (D–F) Muscle from infected WT or Atg16L^HM mice was collected at days 1, 2, and 5 after infection and stained for cleaved caspase-3, E3, or DAPI for nucleus staining (D). The percentage of cleaved capsase-3–positive cells was numerated in all population (E) or in E3⁺ and E3⁻ cells (F). Error bars mean ± SD of three independent experiments. Bars, 60 µm. Student’s test: **, P < 0.05.