Fig. 3: Oenocyte upd3 activates JAK-STAT pathway in cardiomyocytes to induce arrhythmia.
a Representative images of Stat92E immunostaining in the heart of oenocyte-specific upd3 KD ¬(+RU) and control flies (−RU). Flies were treated with normal or paraquat diet for 24 h. Arrows indicate cardiomyocyte nuclei. White boxes indicate the regions shown in the right insets. Scale bar: 20 µm (inset: 5 µm). b Quantification of the Stat92E-positive punctae near cardiomyocyte nucleus. N = 7 flies. Data presented are representative of two independent experiments. c, d QRT-PCR analysis on Socs36E mRNA expression in the heart of control (attP40) and flies with oenocyte-specific upd3 KD under either paraquat treatment or aging. In paraquat treatment (c), 4 independent biological samples are shown, results are pooled from 3 experiments. In aging study (d), flies with two ages (1 week vs 5 weeks) are collected. N = 4 biological samples from 2 independent experiments. e Arrhythmia index of young flies (1-week-old) with heart-specific expression of an activated form of hop (hopTuml) (nleft-right = 21, 26 flies). f Representative M-mode of paraquat-treated wild-type, heart-specific dome and Stat92E RNAi flies. g Arrhythmia Index of paraquat-treated wild-type, heart-specific dome and Stat92E KD flies. Ctrl genotype is Hand>attP40 (nleft-right = 20, 18, 14, 17, 15, 17 flies). h Representative M-mode of heart-specific Stat92E and hop RNAi flies at old ages. i Arrhythmia Index of heart-specific Stat92E and hop RNAi flies at old ages. Ctrl genotype is Hand>attP40. (nleft-right= 28, 33, 18 flies). j Western blot analysis on the hemolymph samples extracted from flies expressing upd3-GFP fusion proteins in oenocytes. Two biological replicates are shown. Total protein loaded onto the Bio-Rad Stain-Free gel was visualized using ChemiDoc MP Imagers after UV activation. Ctrl genotype is PromE>attP40. k Quantification of western blots in j. The data represent the intensity of GFP bands normalized to the total protein. Data are represented as mean ± SEM. P values are calculated using two-tailed unpaired t-test (e, k) or one-way ANOVA (i), or two-way ANOVA (b–d, g) followed by Holm-Sidak multiple comparisons. ns: not significant.
