Fig. 6

( A?B) Quantitative real-time PCR measurement of relative mRNA levels from dissected digestive tracts in control and 6 hr high fat (HF) meal larvae at 6dpf (n = 4 biological replicate pools of 20 fish per condition). The plot indicates the fold increase of relative mRNA levels of indicated genes. ( C) Quantification of total EEC number in control (n = 8) and 6 hr HF fed larvae (n = 6). ( D?G) Representative images of the EEC calcium response to glucose or palmitate stimulation in control ( D, F) and 2 hr thapsigargin (ER stress inducer, 1 µM) treated larvae ( E, G). ( H, I) Quantification of the EEC calcium response toward glucose ( H) and palmitate ( I) in control and 2 hr thapsigargin (1 µM) treated larvae. ( J?K) Quantification of EEC morphology score in control and 10 hr thapsigargin (0.75 µM) or brefeldin A (BFA, 9 µM) treated larvae Tg(gata5:lifeAct-EGFP);Tg(neurod1:RFP) double transgenic line. ( L?M) Confocal projections of control ( J) and 6 hr HF fed ( K) zebrafish intestines. The EECs are marked by Tg(neurod1:RFP), the activation of ER stress is marked by Tg(ef1?:xbp1?-GFP) and DNA is stained with Hoechst 33342 (blue). ( L??M?) Subpanel images showing the activation of ER stress in control ( L?) and 6 hr HF fed ( M?) zebrafish intestines. ( M??) Zoom in view of s-xbp1+ EECs that displayed typical closed morphology in HF fed zebrafish intestine. Yellow arrows in M, M? and M?? indicate EECs with xbp1activation. ( N) Quantification of s-xbp1+ EECs (%) in control and 6 hr HF fed zebrafish larvae. ( O?P) Confocal projection of zebrafish intestine in 10 hours HF fed ( O) and 10 hr HF fed treated animals receiving 0.5 mM TUDCA ( P). EECs are marked with Tg(neurod1:RFP)and the apical region of the intestine is marked with Tg(gata5:lifeAct-EGFP). ( O??P?) Zoom view of EECs in indicated conditions. Yellow arrows in P? indicate EECs? apical extensions. ( Q) Quantification of the EEC morphology score in zebrafish larvae following 10 hr of HF feeding and 10 hr of HF feeding with 0.5 mM TUDCA. Student t-test was performed for statistical analysis. *p<0.05, **p<0.01, ***p<0.001.