An in vivo brain–bacteria interface: the developing brain as a key regulator of innate immunity

摘要

One day after fertilization (early- to mid-gastrula or stage 12), embryos were microinjected with the pathogenic bacteria UTI89. The next day, surgeries were performed for removal of the brain (brainless or BR embryos), a piece of cervical spinal cord (SC embryos) or the tail bud (Tail embryos). Embryos were collected for morphological and molecular analysis during the next three days post-surgery. The bacterial load is represented in red. – Dorsal (left column) and lateral (right column) views of st. 48 embryos belonging Control or Intact (Ctrl; , ) vs. Brainless (BR ; , ) experimental groups. Green and red arrows point, respectively, the control or correct vs. aberrant morphologies after surgery removal. Eyes, gut and branchial arches (ba) are indicated for reference. Left: rostral is up. Right: rostral is left, dorsal is up. Rostral is left and dorsal is up. Scale bar = 500 μm. , Survival rates (plotted as percentage, %) of each experimental group per each infection condition: without infection or not-infected animals (NI; , one-way ANOVA  > 0.05) vs. UTI89 infected animals (UTI, evaluated four days after infection; , one-way ANOVA  h Bacteria load measured and plotted as colony forming units per milliliter (cfu/ml) in independent embryos (dots) belonging each experimental group or surgery condition. Alive embryos were harvested for analysis 48 h after infection. Initial bacteria load or number of bacteria injected (average of three independent replicates) at  = 0 is plotted as a blue-dashed line. One-way ANOVA  > 0.05. Host-Pathogen Response Index (HPRI) = % survival/(1 + log10(CFU + 1)), for each experimental group, as a metric of tolerance. Data represent the mean and S.D. of five independent embryos. One-way ANOVA  g, values after post hoc Bonferroni comparisons are indicated as **    0.01, *    0.05, ns  > 0.05. See also Supplementary Fig. .