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Zelows MM, Cady C, Dharanipragada N, Mead AE, Kipp ZA, Bates EA, Varadharajan V, Banerjee R, Park SH, Shelman NR, Clarke HA, Hawkinson TR, Medina T, Sun RC, Lydic TA, Hinds TD, Brown JM, Softic S, Graf GA, Helsley RN. Loss of carnitine palmitoyltransferase 1a reduces docosahexaenoic acid-containing phospholipids and drives sexually dimorphic liver disease in mice. Mol Metab 2023; 78:101815. [PMID: 37797918 PMCID: PMC10568566 DOI: 10.1016/j.molmet.2023.101815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 09/22/2023] [Accepted: 09/28/2023] [Indexed: 10/07/2023] Open
Abstract
BACKGROUND AND AIMS Genome and epigenome wide association studies identified variants in carnitine palmitoyltransferase 1a (CPT1a) that associate with lipid traits. The goal of this study was to determine the role of liver-specific CPT1a on hepatic lipid metabolism. APPROACH AND RESULTS Male and female liver-specific knockout (LKO) and littermate controls were placed on a low-fat or high-fat diet (60% kcal fat) for 15 weeks. Mice were necropsied after a 16 h fast, and tissues were collected for lipidomics, matrix-assisted laser desorption ionization mass spectrometry imaging, kinome analysis, RNA-sequencing, and protein expression by immunoblotting. Female LKO mice had increased serum alanine aminotransferase levels which were associated with greater deposition of hepatic lipids, while male mice were not affected by CPT1a deletion relative to male control mice. Mice with CPT1a deletion had reductions in DHA-containing phospholipids at the expense of monounsaturated fatty acids (MUFA)-containing phospholipids in whole liver and at the level of the lipid droplet (LD). Male and female LKO mice increased RNA levels of genes involved in LD lipolysis (Plin2, Cidec, G0S2) and in polyunsaturated fatty acid metabolism (Elovl5, Fads1, Elovl2), while only female LKO mice increased genes involved in inflammation (Ly6d, Mmp12, Cxcl2). Kinase profiling showed decreased protein kinase A activity, which coincided with increased PLIN2, PLIN5, and G0S2 protein levels and decreased triglyceride hydrolysis in LKO mice. CONCLUSIONS Liver-specific deletion of CPT1a promotes sexually dimorphic steatotic liver disease (SLD) in mice, and here we have identified new mechanisms by which females are protected from HFD-induced liver injury.
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Affiliation(s)
- Mikala M Zelows
- Department of Pharmaceutical Sciences, University of Kentucky College of Pharmacy, Lexington, KY, USA
| | - Corissa Cady
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Nikitha Dharanipragada
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Anna E Mead
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Zachary A Kipp
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Evelyn A Bates
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, USA
| | | | - Rakhee Banerjee
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Se-Hyung Park
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, USA; Department of Pediatrics and Gastroenterology, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Nathan R Shelman
- Department of Pathology and Laboratory Medicine, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Harrison A Clarke
- Department of Biochemistry & Molecular Biology, University of Florida College of Medicine, Gainesville, FL, USA; Center for Advanced Spatial Biomolecule Research, University of Florida College of Medicine, Gainesville, FL, USA
| | - Tara R Hawkinson
- Department of Biochemistry & Molecular Biology, University of Florida College of Medicine, Gainesville, FL, USA; Center for Advanced Spatial Biomolecule Research, University of Florida College of Medicine, Gainesville, FL, USA
| | - Terrymar Medina
- Department of Biochemistry & Molecular Biology, University of Florida College of Medicine, Gainesville, FL, USA; Center for Advanced Spatial Biomolecule Research, University of Florida College of Medicine, Gainesville, FL, USA
| | - Ramon C Sun
- Department of Biochemistry & Molecular Biology, University of Florida College of Medicine, Gainesville, FL, USA; Center for Advanced Spatial Biomolecule Research, University of Florida College of Medicine, Gainesville, FL, USA
| | - Todd A Lydic
- Department of Physiology, Michigan State University, East Lansing, MI, USA
| | - Terry D Hinds
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, USA; Barnstable Brown Diabetes Center, University of Kentucky College of Medicine, Lexington, KY, USA; Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY, USA
| | - J Mark Brown
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Samir Softic
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, USA; Department of Pediatrics and Gastroenterology, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Gregory A Graf
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY, USA; Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, USA
| | - Robert N Helsley
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, USA; Barnstable Brown Diabetes Center, University of Kentucky College of Medicine, Lexington, KY, USA; Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY, USA; Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, USA; Department of Internal Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Kentucky College of Medicine, Lexington, KY, USA.
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Zelows MM, Cady C, Dharanipragada N, Mead AE, Kipp ZA, Bates EA, Varadharajan V, Banerjee R, Park SH, Shelman NR, Clarke HA, Hawkinson TR, Medina T, Sun RC, Lydic TA, Hinds TD, Brown JM, Softic S, Graf GA, Helsley RN. Loss of Carnitine Palmitoyltransferase 1a Reduces Docosahexaenoic Acid-Containing Phospholipids and Drives Sexually Dimorphic Liver Disease in Mice. bioRxiv 2023:2023.08.17.553705. [PMID: 37645721 PMCID: PMC10462091 DOI: 10.1101/2023.08.17.553705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Background and Aims Genome and epigenome wide association studies identified variants in carnitine palmitoyltransferase 1a (CPT1a) that associate with lipid traits. The goal of this study was to determine the impact by which liver-specific CPT1a deletion impacts hepatic lipid metabolism. Approach and Results Six-to-eight-week old male and female liver-specific knockout (LKO) and littermate controls were placed on a low-fat or high-fat diet (HFD; 60% kcal fat) for 15 weeks. Mice were necropsied after a 16 hour fast, and tissues were collected for lipidomics, matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI), kinome analysis, RNA-sequencing, and protein expression by immunoblotting. Female LKO mice had increased serum alanine aminotransferase (ALT) levels which were associated with greater deposition of hepatic lipids, while male mice were not affected by CPT1a deletion relative to male control mice. Mice with CPT1a deletion had reductions in DHA-containing phospholipids at the expense of monounsaturated fatty acids (MUFA)-containing phospholipids in both whole liver and at the level of the lipid droplet (LD). Male and female LKO mice increased RNA levels of genes involved in LD lipolysis ( Plin2 , Cidec , G0S2 ) and in polyunsaturated fatty acid (PUFA) metabolism ( Elovl5, Fads1, Elovl2 ), while only female LKO mice increased genes involved in inflammation ( Ly6d, Mmp12, Cxcl2 ). Kinase profiling showed decreased protein kinase A (PKA) activity, which coincided with increased PLIN2, PLIN5, and G0S2 protein levels and decreased triglyceride hydrolysis in LKO mice. Conclusions Liver-specific deletion of CPT1a promotes sexually dimorphic steatotic liver disease (SLD) in mice, and here we have identified new mechanisms by which females are protected from HFD-induced liver injury. Graphical Summary
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