Increased expression of lipogenic and stress-responsive genes in dtp larvae, and rescue of dtp steatosis and liver degeneration with tnfa knockdown. (A-D) Expression levels of peroxisome proliferator-activated receptor gamma (pparg, A), sterol response element binding protein 1 (srebp1, B), glutathione peroxidase (gpx, C) and tumor necrosis factor alpha (tnfa, D) in 4-dpf dtp versus wild-type (wt) siblings. Inset for D shows Tnfα western blot in 5-dpf dtp larvae. *P<0.05, **P<0.005; NS, not significant (P=0.07). (E,F) Whole-mount RNA in situ hybridization showing enhanced tnfa expression in the liver (outlined), intestine (arrow) and swim bladder (*) of a dtp larva (F) as compared with a wild-type sibling (E). (G) Western blot showing reduced Tnfα protein in tnfa morpholino-injected larvae. (H) Lateral view of a fixed 5-dpf dtp larva injected with tnfa antisense morpholino oligonucleotide at 2 dpf; liver size is enlarged (outlined), compare with live dtp 5-dpf larva depicted in Fig. 1. (I) Liver rescue in tnfa morpholino-injected dtp mutant as revealed by transferrin (tfa) in situ hybridization. (J,K) tnfa knockdown also rescues dtp liver histology (compare with Fig. 1J). (L) Mitochondrial ultrastructure is improved and steatosis is rescued by tnfa knockdown. eso, esophagus; li, liver; m, mitochondria.
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