Fig. 1: Mucin secretion defects in Syt2-mutant mice.
From: Inhibition of calcium-triggered secretion by hydrocarbon-stapled peptides
a, Transverse sections of bronchial airways of mice stained with periodic acid fluorescent Schiff (PAFS) to demonstrate mucin with red fluorescence. Top, in naive mice without airway inflammation, scant intracellular mucin is visible. Treatment with IL-13 increases mucin synthesis, resulting in abundant intracellular mucin. Bottom, subsequent treatment with ATP induces mucin secretion, reducing intracellular mucin in WT C57Bl/6J mice (WT) and Syt2F/F mice (F/F), but not in Syt2D/D mice (D/D). Scale bar, 50 µm. b, Fractional mucin secretion was measured by analysing images of airways of mice treated with IL-13 alone and comparing those with those of mice treated with IL-13 followed by ATP, as shown in a. Individual data points and box plots are shown for two independent sets of experiments combined to give a total n mice (indicated below each box plot) per group (Supplementary Table 1). Comparison with the Syt2F/F group of mice was performed using two-tailed unpaired Student’s t-tests; ***P = 0.00026. c, Transverse sections of bronchial airways of mice treated with IL-13, then with methacholine (Mch) to induce smooth muscle contraction and mucin secretion, and fixed with methacarn and stained with PAFS to demonstrate lumenal mucus and residual intracellular mucin. Scale bar, 50 µm. d, The sum of the lumenal mucus cross-sectional area in the left lung measured at 500 µm intervals. Individual data points and box plots are shown for two independent sets of experiments combined to give a total of n mice (indicated below each box plot) per group (Supplementary Table 1). Comparison with the Syt2F/F group of mice was performed using two-tailed unpaired Student’s t-tests; **P = 0.0012.
