1
|
Chuang JC, Clifford AJ, Kim SH, Novotny JA, Kelly PB, Holstege DM, Walzem RL. Separation of Lipoproteins for Quantitative Analysis of 14C-Labeled Lipid-Soluble Compounds by Accelerator Mass Spectrometry. Int J Mol Sci 2024; 25:1856. [PMID: 38339135 PMCID: PMC10855872 DOI: 10.3390/ijms25031856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/26/2024] [Accepted: 01/29/2024] [Indexed: 02/12/2024] Open
Abstract
To date, 14C tracer studies using accelerator mass spectrometry (AMS) have not yet resolved lipid-soluble analytes into individual lipoprotein density subclasses. The objective of this work was to develop a reliable method for lipoprotein separation and quantitative recovery for biokinetic modeling purposes. The novel method developed provides the means for use of small volumes (10-200 µL) of frozen plasma as a starting material for continuous isopycnic lipoprotein separation within a carbon- and pH-stable analyte matrix, which, following post-separation fraction clean up, created samples suitable for highly accurate 14C/12C isotope ratio determinations by AMS. Manual aspiration achieved 99.2 ± 0.41% recovery of [5-14CH3]-(2R, 4'R, 8'R)-α-tocopherol contained within 25 µL plasma recovered in triacylglycerol rich lipoproteins (TRL = Chylomicrons + VLDL), LDL, HDL, and infranatant (INF) from each of 10 different sampling times for one male and one female subject, n = 20 total samples. Small sample volumes of previously frozen plasma and high analyte recoveries make this an attractive method for AMS studies using newer, smaller footprint AMS equipment to develop genuine tracer analyses of lipophilic nutrients or compounds in all human age ranges.
Collapse
Affiliation(s)
| | | | - Seung-Hyun Kim
- Department of Applied Bioscience, College of Life and Environmental Science, Konkuk University, Seoul 143-701, Republic of Korea;
| | - Janet A. Novotny
- U.S. Department of Agriculture, Beltsville Human Nutrition Research Center, 10300 Baltimore Avenue, Beltsville, MD 20705, USA;
| | - Peter B. Kelly
- Department of Chemistry, University of California, Davis, CA 95616, USA
| | - Dirk M. Holstege
- UC Davis Analytical Lab, University of California, Davis, CA 95616, USA
| | - Rosemary L. Walzem
- Poultry Science Department, Graduate Faculty of Nutrition, Texas A&M University, College Station, TX 77843, USA
| |
Collapse
|
2
|
Bond LM, Ibrahim A, Lai ZW, Walzem RL, Bronson RT, Ilkayeva OR, Walther TC, Farese RV. Fitm2 is required for ER homeostasis and normal function of murine liver. J Biol Chem 2023; 299:103022. [PMID: 36805337 PMCID: PMC10027564 DOI: 10.1016/j.jbc.2023.103022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 01/25/2023] [Accepted: 01/30/2023] [Indexed: 02/17/2023] Open
Abstract
The endoplasmic reticulum (ER)-resident protein fat storage-inducing transmembrane protein 2 (FIT2) catalyzes acyl-CoA cleavage in vitro and is required for ER homeostasis and normal lipid storage in cells. The gene encoding FIT2 is essential for the viability of mice and worms. Whether FIT2 acts as an acyl-CoA diphosphatase in vivo and how this activity affects the liver, where the protein was discovered, are unknown. Here, we report that hepatocyte-specific Fitm2 knockout (FIT2-LKO) mice fed a chow diet exhibited elevated acyl-CoA levels, ER stress, and signs of liver injury. These mice also had more triglycerides in their livers than control littermates due, in part, to impaired secretion of triglyceride-rich lipoproteins and reduced capacity for fatty acid oxidation. We found that challenging FIT2-LKO mice with a high-fat diet worsened hepatic ER stress and liver injury but unexpectedly reversed the steatosis phenotype, similar to what is observed in FIT2-deficient cells loaded with fatty acids. Our findings support the model that FIT2 acts as an acyl-CoA diphosphatase in vivo and is crucial for normal hepatocyte function and ER homeostasis in the murine liver.
Collapse
Affiliation(s)
- Laura M Bond
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA; Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA
| | - Ayon Ibrahim
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA; Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA
| | - Zon W Lai
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA; Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA; Harvard T.H. Chan Advanced Multi-omics Platform, Department of Molecular Metabolism, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Rosemary L Walzem
- Department of Poultry Science and Graduate Faculty of Nutrition, Kleberg Animal & Food Science Center, Texas A&M University, College Station, Texas, USA
| | - Roderick T Bronson
- Rodent Histopathology Core, Harvard Medical School, Boston, Massachusetts, USA
| | - Olga R Ilkayeva
- Division of Endocrinology, Metabolism, and Nutrition, Department of Medicine, Duke Molecular Physiology Institute, Sarah W. Stedman Nutrition and Metabolism Center, Duke University School of Medicine, Durham, North Carolina, USA
| | - Tobias C Walther
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA; Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA; Harvard T.H. Chan Advanced Multi-omics Platform, Department of Molecular Metabolism, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, USA; Cell Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, New York, USA; Broad Institute of Harvard and MIT, Cambridge, Massachusetts, USA; Howard Hughes Medical Institute, Boston, Massachusetts, USA.
| | - Robert V Farese
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA; Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA; Cell Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, New York, USA; Broad Institute of Harvard and MIT, Cambridge, Massachusetts, USA.
| |
Collapse
|
3
|
Lytle JR, Price T, Crouse SF, Smith DR, Walzem RL, Smith SB. Consuming High-Fat and Low-Fat Ground Beef Depresses High-Density and Low-Density Lipoprotein Cholesterol Concentrations, and Reduces Small, Dense Low-Density Lipoprotein Particle Abundance. Nutrients 2023; 15:nu15020337. [PMID: 36678207 PMCID: PMC9861690 DOI: 10.3390/nu15020337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/05/2023] [Accepted: 01/07/2023] [Indexed: 01/11/2023] Open
Abstract
We hypothesized that consumption of high-fat (HF) ground beef (24% fat) would not affect plasma concentrations of high-density lipoprotein cholesterol (HDL-C) or low-density lipoprotein (LDL-C), whereas low-fat (LF) ground beef (5% fat) would decrease HDL-C and LDL-C concentrations. In a randomized 2-period crossover, controlled feeding trial, 25 men (mean age and body mass index, 40 years and 31.2) consumed 115-g HF or LF patties, 5/week for 5 weeks with a 4-week washout. The HF treatment increased % energy from fat (p = 0.006) and saturated fat (p = 0.004) and tended (p = 0.060) to depress % energy from carbohydrates. The HF and LF treatments decreased the plasma concentrations of HDL-C (p = 0.001) and LDL-C (p = 0.011). Both ground beef treatments decreased the abundance of HDL3a and increased the abundance of HDL3 (p ≤ 0.003); the LF treatment also decreased the abundance of HDL2b and HDL2a (p ≤ 0.012). The HF and LF treatments decreased the abundance of LDL3 and LDL4 (p ≤ 0.024) and the HF treatment also decreased LDL5 (p = 0.041). Contrary to our hypothesis, the HF treatment decreased plasma HDL-C and LDL-C concentrations despite increased saturated fat intake, and both treatments decreased the abundance of smaller, denser LDL subfractions.
Collapse
Affiliation(s)
- Jason R. Lytle
- Department of Health & Kinesiology, Texas A&M University, College Station, TX 77843, USA
| | - Tara Price
- Department of Nutrition and Food Science, College Station, TX 77843, USA
| | - Stephen F. Crouse
- Department of Health & Kinesiology, Texas A&M University, College Station, TX 77843, USA
| | - Dana R. Smith
- Independent Nutrition Consultant, College Station, TX 77845, USA
| | - Rosemary L. Walzem
- Poultry Science, Texas A&M University, College Station, TX 77843, USA
- Graduate Faculty of Nutrition, Texas A&M University, College Station, TX 77843, USA
| | - Stephen B. Smith
- Graduate Faculty of Nutrition, Texas A&M University, College Station, TX 77843, USA
- Department of Animal Science, Texas A&M University, College Station, TX 77843, USA
- Correspondence: ; Tel.: +1-979-845-3939
| |
Collapse
|