Bilirubin Nanoparticle Treatment in Obese Mice Inhibits Hepatic Ceramide Production and Remodels Liver Fat Content

Abstract

Studies have indicated that increasing plasma bilirubin levels might be useful for preventing and treating hepatic lipid accumulation that occurs with metabolic diseases such as obesity and diabetes. We have previously demonstrated that mice with hyperbilirubinemia had significantly less lipid accumulation in a diet-induced non-alcoholic fatty liver disease (NAFLD) model. However, bilirubin’s effects on individual lipid species are currently unknown. Therefore, we used liquid chromatography-mass spectroscopy (LC-MS) to determine the hepatic lipid composition of obese mice with NAFLD treated with bilirubin nanoparticles or vehicle control. We placed the mice on a high-fat diet (HFD) for 24 weeks and then treated them with bilirubin nanoparticles or vehicle control for 4 weeks while maintaining the HFD. Bilirubin nanoparticles suppressed hepatic fat content overall. After analyzing the lipidomics data, we determined that bilirubin inhibited the accumulation of ceramides in the liver. The bilirubin nanoparticles significantly lowered the hepatic expression of two essential enzymes that regulate ceramide production, Sgpl1 and Degs1. Our results demonstrate that the bilirubin nanoparticles improve hepatic fat content by reducing ceramide production, remodeling the liver fat content, and improving overall metabolic health.

Cardiac lipotoxicity and fibrosis underlie impaired contractility in a mouse model of metabolic dysfunction‐associated steatotic liver disease

“…Western blots were performed on cardiac and liver samples (30 μg) as we previously described 13,14,18 . Membranes were incubated overnight at 4°C with the following antibodies: ANP (1:1000, Abcam, ab180649), BNP (1:1000, Santa Cruz Biotechnology, sc‐271185), cleaved anti‐caspase‐3 (1:1000, Cell Signaling Technology, #9661), Pro‐caspase‐3 (1:1000, NovusBio, B‐6), B‐cell lymphoma protein 2 (BCl‐2) (1:1000, Santa Cruz Biotechnology, sc‐7382), B‐cell lymphoma protein 2‐associated X (BAX) (1:1000, Invitrogen, YB3837921), D‐β‐hydroxybutyrate dehydrogenase I (BDH1) (1:2000,15417, Thermofisher), and heat shock protein 90 (1:5000, Santa Cruz Biotechnology, sc‐13119).…”

“…Western blots were performed on cardiac and liver samples (30 μg) as we previously described. 13 , 14 , 18 Membranes were incubated overnight at 4°C with the following antibodies: ANP (1:1000, Abcam, ab180649), BNP (1:1000, Santa Cruz Biotechnology, sc‐271185), cleaved anti‐caspase‐3 (1:1000, Cell Signaling Technology, #9661), Pro‐caspase‐3 (1:1000, NovusBio, B‐6), B‐cell lymphoma protein 2 (BCl‐2) (1:1000, Santa Cruz Biotechnology, sc‐7382), B‐cell lymphoma protein 2‐associated X (BAX) (1:1000, Invitrogen, YB3837921), D‐β‐hydroxybutyrate dehydrogenase I (BDH1) (1:2000,15417, Thermofisher), and heat shock protein 90 (1:5000, Santa Cruz Biotechnology, sc‐13119). After three washes in TBS + 0.1% Tween 20, the membrane was incubated with an infrared donkey anti‐goat (IRDye 800LI‐COR Biosciences, 926‐32214) or donkey anti‐rabbit (IRDye 800LI‐COR Biosciences, 926‐32214) or goat anti‐mouse (IRDye 680, LI‐COR Biosciences, 926‐68020) secondary antibody (LI‐COR Biosciences) (1:2,000 dilution in TBS) for 2 hrs at 4°C.…”

Intermittent glucocorticoid treatment improves muscle metabolism via the PGC1α/Lipin1 axis in an aging-related sarcopenia model

“…Lipid identification and quantitation was performed with the methods previously reported (62)(63)(64). Lipid species with coefficients of variation greater than 20% between the technical replicates were excluded from further analysis.…”