A Lipidomic Readout of Disease Progression in A Diet-Induced Mouse Model of Nonalcoholic Fatty Liver Disease - PubMed (original) (raw)

PMID: 26330688
PMCID: PMC4530706

A Lipidomic Readout of Disease Progression in A Diet-Induced Mouse Model of Nonalcoholic Fatty Liver Disease

Arun J Sanyal et al. Trans Am Clin Climatol Assoc. 2015.

Abstract

Multiple changes in lipid metabolism occur in nonalcoholic fatty liver disease. However, it is not known which of these contribute to disease progression. The objective of this study was to define changes in hepatic lipid composition over time in a diet-induced model of nonalcoholic fatty liver disease to identify changes associated with disease progression. A lipidomic approach was used to quantify individual lipid species with lipid classes of interest including diacylglycerols (DAG), cholesterol, phospholipids, plasmalogens, sphingolipids, and eicosanoids. C57b/S129J mice fed a high-fat, high-cholesterol diet developed fatty liver, inflammation, and ballooning by 16 weeks and extensive fibrosis by week 52. There was a marked increase in monounsaturated fatty acid containing DAGs and cholesterol esters by week 16 which decreased by week 52. The changes in DAG were associated with a 500- to 600-fold increase in phosphatidic acid (< 0.001) and its downstream product phosphatidylglycerol (P <0.01) whereas phosphatidylethanolamine, phosphatidylcholine, and phsophatidylserine all decreased. Disease progression was associated with a significant further decrease in phosphatidylcholine and phosphatidylethanolamine while several lysolecithin species increased. Disease progression was associated with a significant increase in the plasmalogen PC-P 16:0/16:1. Saturated fatty acid (16:0 and 18:0) containing ceramides, sphingosine, sphingosine-1-phosphate, dihydrosphingosine, and dihydrophingosine-1-phosphate increased by week 16 after high-fat high-cholesterol diet. Globotrioseacylceramide (GB3) also increased significantly by week 16 and increased further with disease progression. 12-hydroxyeicosatetranoic acid decreased at week 16 but increased with disease progression. In conclusion, multiple lipids were associated with disease progression and provide clues regarding lipid drivers of nonalcoholic steatohepatitis.

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Conflict of interest statement

Potential Conflicts of Interest: Dr Sanyal has stock options in Genfit. He has served as a consultant to AbbVie, Astra Zeneca, Nitto Denko, Nimbus, Salix, Tobira, Takeda, Fibrogen, Immuron, Exhalenz, and Genfit. He has been an unpaid consultant to Intercept and Echosens. His institution has received grant support from Gilead, Salix, Tobira, and Novartis.

Figures

Fig. 1

Histology of mice fed chow or high fat high calorie diet (HFHCD) for 16 and 52 weeks. (A,B) In chow-fed mice, the liver histology was normal at both 16 and 52 weeks, respectively. (C,D) In HFHCD-fed mice, the liver developed a light tan color and some nodularity by week 52. HFHCD-fed mice also developed macrovesicular steatosis, foci of small droplet steatosis, and scattered inflammation at 16 weeks (E) along with focal cytological ballooning (arrow) and pericellular fibrosis (E–F). By 52 weeks, there was prominence of macrovesicular and centrilobular small droplet steatosis along with extensive pericellular fibrosis and areas of bridging fibrosis (G–H).

Fig. 2

Changes in diacylglycerols, cholesterol esters, and phospholipids. Total diacylglycerols (DAGs) increased significantly by week 16 of high-fat, high-cholesterol diet (HFHCD) (P <0.05) compared to chow-fed mice (A). Monounsaturated fatty acid (MUFA) −and saturated fatty acid (SFA) −containing DAGs increased significantly at both 16 and 52 weeks, whereas polyunsaturated fatty acid (PUFA) −containing DAGs decreased significantly at both time points. In mice fed an HFHCD, there was a significant increase in cholesterol esters (CEs) both at 16 weeks and 52 weeks (P <0.001) compared to chow-fed mice (B). CE was enriched with SFA and MUFA both at week 16 and week 52 in the former group. The levels of CEs decreased in HFHCD-fed mice from week 16 to week 52 (P <0.01), accompanied by a decrease in SFA-, MUFA-, and PUFA-containing CEs. There was a significant increase in phosphatidic acid (PA) by week 16 (P <0.001) in HFHCD-fed mice compared to chow-fed mice (C). This was accompanied by an increase in its downstream product phosphatidylglycerol (PG) (P <0.001). Disease progression in HFHCD-fed mice from week 16 to week 52 was accompanied by continued increase in PG and PA (non-significant) and a significant decrease in PC and PE (P <0.01 for both) (D).

Fig. 3

Changes in sphingolipids. Ceramides containing saturated fatty acid (SFA) (16:0 and 18:0) increased at week 16 in high-fat, high-cholesterol diet (HFHCD)−fed mice compared to chow-fed mice (A). This was accompanied by a significant increase in sphingosine, sphingosine-1-phosphate as well as dihydrosphingosine and dihydrosphingosine-1-phosphate (B–C). From week 16 to week 52 in HFHCD-fed mice, sphingosine remained relatively unchanged while dihydrophingosine and sphingosine-1-phosphate declined significantly (P <0.01 and <0.001, respectively) and dihydrosphingosine-1-phosphate increased significantly (P <0.05). Several species of sphingomyelins also increased, although only one reached statistical significance (18:1/15:0–18:1/14:1) (3). Both galactosylceramide and glucosylceramide decreased whereas lactosylceramide and globotrioseacylceramide (GB3) increased by week 16 (P =ns) in HFHCD-fed mice compared to chow-fed mice (E).

Fig. 4

Changes in ceramide and globotrioseacylceramide (GB3) with disease progression from 16 weeks to 52 weeks of high-fat, high-cholesterol diet (HFHCD) −fed mice. Cer d18:1/24:1 and 18:1/16:0 increased significantly (P <0.01 and P <0.05, respectively) at week 52 compared to week 16 in HFHCD-fed mice (A). GB3 increased further by week 52 in HFHCD-fed mice compared to chow-fed mice and also relative to HFHCD-fed mice at 16 weeks (B–C). Specifically, 18:1/22:1 and 18:1/16:0 increased significantly at week 52 (HFHCD versus chow diet). 18:1/24:1 increased significantly in mice fed HFHCD for 52 weeks compared to HFHCD for 16 weeks.

Fig. 5

Changes in eicosanoids. Most measured eicosanoids in high-fat, high-cholesterol diet (HFHCD) −fed mice at 16 weeks, with the exception of thromboxane B2 and PGF2 alpha, decreased relative to chow-fed mice (A). By week 52, compared to chow-fed mice, there was a further decrease in multiple eicosanoids, many of which were statistically significant (B). 12-HETE, the metabolic product of 12/15 lipoxygenase (mouse Alox 15 gene) from arachidonic acid, decreased in HFHCD-fed mice at week 16 compared to chow-fed mice. This trend, however, reversed and was higher compared to chow-fed mice by week 52. When eicosanoid levels were compared in mice fed an HFHCD for 52 weeks versus 16 weeks, total eicosanoids (P <0.05) and arachidonic acid increased significantly (P <0.01). Multiple eicosanoids also trended upwards including 12-HETE and 15-HETE (C).

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A Lipidomic Readout of Disease Progression in A Diet-Induced Mouse Model of Nonalcoholic Fatty Liver Disease - PubMed (original) (raw)