Fig 2: The effects of olanzapine (OLZ) on plasma triglyceride and apoA5 levels in mice. (A) Plasma triglycerides and (B) apoA5 levels in olanzapine-treated mice. Hepatic apoA5 protein (C,D) and ApoA5 mRNA levels (E) in olanzapine-treated mice. Data represent the mean ± SEM. *p < 0.05 vs. control, **p < 0.01 vs. control, # p < 0.05 vs. OLZ 6 mg/kg group.

Fig 3: Effects of olanzapine-induced triglyceride accumulation in the liver and on apoA5 subcellular localization alternation. (A) H&E and ORO staining and (B) double immunofluorescence of mouse liver sections. The liver sections were fixed, permeabilized, and incubated with a mouse monoclonal anti-apoA5 antibody, followed by incubation with Alexa 647-conjugated anti-mouse IgG (red). The nuclei of the corresponding cells were visualized using 4′,6-diamidino-2-phenylindole (DAPI) staining (blue). Lipid droplets were stained with BODIPY 493/503 (green). HepG2 cells (C) and primary mouse hepatocytes (D) were homogenized and subjected to sucrose gradient centrifugation (Klaunig et al., 1981a). Western blotting results against apoA5 antibody. Lanes 1-3, proteins from the whole cell in the control group; lanes 4-6, proteins from whole cell in the olanzapine 100 µmol/L group; lanes 7-9, proteins from the lipid droplet fractions in the control group; lanes 10-12, proteins from the lipid droplet (LD) fractions in the olanzapine 100 µmol/L group. Data represent the mean ± SEM. LD: lipid droplet. ** p < 0.01 vs. lanes 1-3, *** p < 0.001 vs. lanes 1-3, △△△ p < 0.001 vs. lanes 7-9. and& p < 0.01 vs. lanes 4-6.

Fig 4: Defects of sorting and secretion of hepatic apoA5 by olanzapine leads to hypertriglyceridemia and lipid droplets accumulation in the liver. ApoA5 is synthesized in the endoplasmic reticulum of hepatocytes and then transported to the Golgi body, which releases it, as needed. Olanzapine intervention does not affect the processes of apoA5 transcription and translation but disturbs hepatic sorting and secretion of apoA5 into the blood, and the reduction of circulating apoA5 results in hypertriglyceridemia. Moreover, apoA5 accumulation in the liver promotes the formation of lipid droplets (LD), inhibits lipid-droplet hydrolysis, and promotes triglyceride accumulation in hepatocytes, potentially increasing the risk of NAFLD.

Fig 5: The effects of olanzapine (OLZ) on medium triglyceride levels, apoA5 protein and APOA5/apoA5 mRNA expression in human and mouse hepatocytes in vitro. Triglyceride levels of medium in human hepatocytes (A). Intracellular apoA5 protein levels (B), apoA5 protein levels in the medium (C) (70 μg protein was loaded per lane and loading was confirmed by Ponceau-staining) and APOA5 mRNA (D) in HepG2 cells. Triglyceride levels of medium in primary mouse hepatocytes (E). Intracellular apoA5 protein levels (F), apoA5 protein levels in the medium (G) (100 μg protein was loaded per lane and loading was confirmed by Ponceau-staining) and ApoA5 mRNA (H) in primary mouse hepatocytes. Data represent the mean ± SEM. * p < 0.05 vs. control, ** p < 0.01 vs. control, ※※ p < 0.01 vs. olanzapine (OLZ) 100 µM group, ※※※ p < 0.001 vs. olanzapine (OLZ) 100 µM group.