Fig. 6

Interleukin-17 regulates keratinocyte cytonemes. (A) Representative images of krt4:palmEGFP injected cells in control or Tg(mpeg1:il17a). (B) Significant reduction in cytoneme extension in response to overexpressed il17a ligands in the epidermis (p<0.0001, N=3 larvae per group). (C) Representative images of krt4:palmEGFP injected keratinocytes in WT or il17a-/- mutants. (D) Cytoneme extension frequency increased significantly in il17a+/- or il17a-/- mutants as compared to their wild-type siblings (F2, 247=17.85, p<0.0001, N=250 cells, 9 larvae total). (E) FACS-sorted krt4+ peridermal cells from Tg(krt4:palmEGFP; krt4:il17rd) or Tg(krt4:palmEGFP; krt4:il17ra1a) show significantly reduced Cdc42 (p=0.0341 for il17rd, p=0.01 for il17ra1a, N=3 independent experiments) and Rac1 expression (p=0.0189 for il17rd, p=0.0017 for il17ra1a, N=4 independent experiments). (F) il17rd-or il17ra1a overexpressing krt4+ keratinocytes exhibit disorganization of microridges (arrowheads), with (G) significantly reduced branch lengths of microridges in the transgenic animals (F2, 2311=11.11, p<0.0001, N=68 cells, 9 larvae total). (H) Simultaneous overexpression of cdc42DN and il17rd or il17ra1a in krt4+ keratinocytes further reduces cytoneme extension (il17rd: p<0.0001, N=164 cells, 7 larvae total, il17ra1a: p<0.0001, N=115 cells, 6 larvae total). Statistical significances were assessed by One-way ANOVA followed by Tukey’s HSD post hoc test or Student t test. Scale bars: 20 µm (A, C, F). Error bars indicate mean ± SEM.