3B). Whole-mount ORO staining revealed that hi559 larvae

have fatty livers (Fig. 3C). ORO staining of frozen histological sections revealed substantial fat accumulation in the form of small and large lipid droplets in hi559 hepatocytes (Fig. 3D). At the onset of NAFLD at 5 dpf, the hi559 liver displayed admixture of normal hepatocytes and foci of microvesicular and macrovesicular steatosis, without apparent necrosis (Fig. 4B,E). However, with progression of NAFLD, most hepatocytes exhibited severe macrovesicular steatosis, and some displayed fragmented nuclei (Fig. 4C,D). In some cases of severely steatotic liver, hepatic sinusoids Vismodegib manufacturer appeared smaller (Supporting Fig. 6). The distortion of the sinusoid architecture may be attributed to the grossly enlarged hepatocyte plates compressing the adjacent sinusoids. Hepatocellular injury in the form of ballooning degeneration, apoptosis, and necrotic foci were prominent in hi559 liver by 6 dpf (Fig. 4D,F). The ballooned hepatocytes often have rarefied cytoplasm containing perinuclear hyaline inclusion bodies; therefore,

many of the characteristic histological features of NAFLD, such as ICG-001 enlarged hepatocytes, cytoplasmic clearing, accumulation of small and large membrane-bound lipid, and subsequent necrosis are observed in hi559 livers.1, 28 Despite the severe hepatic histopathology reminiscent of NAFLD, inflammation was not conspicuous in hi559 livers at the histological level, although we noticed the presence of macrophages adjacent to the necrotic hepatocytes ultrastructurally, indicating mild inflammation. The paucity of inflammation MCE公司 may be attributed to an incompletely matured zebrafish immune system at this stage of

larval development. We performed Affymetrix array analyses to decipher dysregulated pathways and gene networks associated with the hi559 phenotype. Our analyses revealed a set of 465 genes that were significantly differentially regulated (P < 0.05) in hi559 compared with wild-type siblings at 5 dpf, 186 of which are up-regulated. GSEA revealed enrichment of a set of genes involved in ERSR/UPR (Fig. 5A,B). We noticed significant up-regulation of critical ERSR indicators in the mutant. Many of these genes encode ER resident proteins that collectively take part in UPR or in Ca2+ homeostasis, including calr, hspa5/bip/grp78, hsp90b1/grp94, caln, and atf6 (Fig. 5). We subsequently compared our gene expression profile with a previously published gene set on hepatic ER stress in mice29 and found a significant overlap between the two (Fig. 5C,D). Ingenuity’s pathway analysis identified acute phase response signaling as the top-most up-regulated canonical pathways, suggesting activated transcription of immune/inflammatory response factors in hi559 larvae (data not shown).