Figure 8: Irg1l regulates β-oxidation-driven mROS production within epidermal cells that elevate mitochondrial uptake of fatty acids following infection.

(a) Detection of mROS within epidermal cells overlying infection region. (b) Line fluorescence intensity measurements, for line shown in a, for CellROX and MitoTracker probes demonstrating overlapping peak fluorescence intensities. (c) Quantification of mROS within individual control MO-injected and Irg1l-depleted larvae following PBS control and Salmonella injection, as detected at 3.5 hpi (mean±s.d.; n=2 separate infection experiments). (d) Quantification of mROS (as in c) within individual DMSO- and etomoxir-treated larvae injected with PBS or Salmonella (mean±s.d.; n=2 separate infection experiments). (e) Expression of mmp9 within DMSO- and etomoxir-treated larvae following infection, as detected at 4 hpi (n=2 separate infection experiments, lateral views, anterior to left). Remainder of infected DMSO-treated larvae (4/34) displayed weak epidermal mmp9 expression. (f) Quantification of Mpeg1⁺ macrophages within the midbrain/hindbrain region of DMSO- and etomoxir-treated Tg(mpeg1:EGFP) larvae at 4 hpi, following PBS or Salmonella injections (mean±s.d.; n=2 separate infection experiments). (g) Live imaging of BODIPY FL C₁₆ and MitoTracker probe within epidermal cells overlying the midbrain/hindbrain region following Salmonella injection. (h) Line fluorescence intensity measurements, for line shown in g, for BODIPY FL C₁₆ and MitoTracker probes demonstrating overlapping peak fluorescence intensities. (i,j) Live imaging mitochondrial uptake of BODIPY FL C₁₆ within epidermal cells overlying the midbrain/hindbrain region following PBS (i) or Salmonella (j) injection, as detected at 4 hpi (dorsal views, anterior to left). BODIPY FL C₁₆ fluorescence intensity is displayed as a colormap, with warmer colours representing higher signal intensities. (k) Quantification of total fluorescence intensities of BODIPY FL C₁₆ within epidermal cells overlaying the midbrain/hindbrain region for individual larvae as shown in i and j (mean±s.d.; n=2 separate infection experiments). Numbers represent frequencies of larvae with displayed phenotypes. Scale bars, 10 μm in a; 100 μm in e; 5 μm in g; 20 μm in i. Statistical significance determined using a Student’s t-test. **P-value <0.01; ***P-value <0.001; ****P-value <0.0001.