Fig. 7

Il1b-mediated inflammation is required for normal regeneration.

(A) Fin fold regeneration in WT larvae treated with Dex. Regeneration was retarded following treatment with Dex but not vehicle DMSO (arrowheads). Scale bar, 100 μm. (B) Quantification for (A) (posterior to the notochord). (C) BrdU incorporation in larvae treated with DMSO or Dex. BrdU labeling, 0–24 hpa. Scale bar, 50 μm. (D) Quantification for (C) (bracketed areas). BrdU-positive cells were significantly reduced following Dex treatment. (E) Detection of junba expression using ISH and fgf20a expression using the HGn21A enhancer-trap line (Shibata et al., 2016) in DMSO- or Dex-treated larvae. The expression of junba and fgf20a was also significantly downregulated following Dex treatment. Arrowheads indicate EGFP expression at amputation sites. Scale bars, 50 μm (F) Fin fold regeneration in larvae injected with std or il1b MO. The knockdown of il1b reduced fin fold regeneration. Scale bar, 100 μm. (G) Quantification for (F) (posterior to the notochord). (H) BrdU incorporation in larvae injected with std or il1b MO. BrdU labeling, 0–24 hpa. Scale bar, 50 μm. (I) Quantification for (H) (bracketed areas). (J) Detection of junba expression using ISH and fgf20a expression using the HGn21A line in larvae injected with std or il1b MO. The expression of junba and fgf20a was downregulated following il1b knockdown as in the Dex-treated larvae. Arrowheads indicate EGFP expression atamputation sites. Scale bars, 50 μm. (K) Schematic of the procedure of il1b overexpression in uninjured WT larvae. Heat shock was applied twice before fixation. (L) ISH analysis of fn1b, junba, and junbb in WT and Tg(hsp70l:il1b). il1b overexpression stimulated ectopic expression of regeneration-induced genes in uninjured larvae. Scale bar, 50 μm. In (A) and (F), dotted lines indicate amputation planes and fin fold outlines. In (B), (D), (G), and (I), data are presented as means ± SEM. Student’s t test, **p<0.01; ***p<0.001.