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Klag KA, Bell R, Jia X, Seguin A, Maschek JA, Bronner M, Cox JE, Round JL, Ward DM. Low-Iron Diet-Induced Fatty Liver Development Is Microbiota Dependent and Exacerbated by Loss of the Mitochondrial Iron Importer Mitoferrin2. Nutrients 2024; 16:1804. [PMID: 38931165 PMCID: PMC11206261 DOI: 10.3390/nu16121804] [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: 05/01/2024] [Revised: 06/03/2024] [Accepted: 06/04/2024] [Indexed: 06/28/2024] Open
Abstract
Iron deficiency is the number one nutritional problem worldwide. Iron uptake is regulated at the intestine and is highly influenced by the gut microbiome. Blood from the intestines drains directly into the liver, informing iron status and gut microbiota status. Changes in either iron or the microbiome are tightly correlated with the development of metabolic dysfunction-associated steatotic liver disease (MASLD). To investigate the underlying mechanisms of the development of MASLD that connect altered iron metabolism and gut microbiota, we compared specific pathogen free (SPF) or germ-free (GF) mice, fed a normal or low-iron diet. SPF mice on a low-iron diet showed reduced serum triglycerides and MASLD. In contrast, GF low-iron diet-fed mice showed increased serum triglycerides and did not develop hepatic steatosis. SPF mice showed significant changes in liver lipid metabolism and increased insulin resistance that was dependent upon the presence of the gut microbiota. We report that total body loss of mitochondrial iron importer Mitoferrin2 (Mfrn2-/-) exacerbated the development of MASLD on a low-iron diet with significant lipid metabolism alterations. Our study demonstrates a clear contribution of the gut microbiome, dietary iron, and Mfrn2 in the development of MASLD and metabolic syndrome.
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Affiliation(s)
- Kendra A. Klag
- Department of Pathology, Division of Microbiology and Immunology, University of Utah School of Medicine, Salt Lake City, UT 84132, USA; (K.A.K.); (R.B.); (X.J.); (A.S.); (M.B.); (J.L.R.)
| | - Rickesha Bell
- Department of Pathology, Division of Microbiology and Immunology, University of Utah School of Medicine, Salt Lake City, UT 84132, USA; (K.A.K.); (R.B.); (X.J.); (A.S.); (M.B.); (J.L.R.)
| | - Xuan Jia
- Department of Pathology, Division of Microbiology and Immunology, University of Utah School of Medicine, Salt Lake City, UT 84132, USA; (K.A.K.); (R.B.); (X.J.); (A.S.); (M.B.); (J.L.R.)
| | - Alexandra Seguin
- Department of Pathology, Division of Microbiology and Immunology, University of Utah School of Medicine, Salt Lake City, UT 84132, USA; (K.A.K.); (R.B.); (X.J.); (A.S.); (M.B.); (J.L.R.)
| | - J. Alan Maschek
- Metabolomics Core Research Facility, University of Utah, Salt Lake City, UT 84112, USA; (J.A.M.); (J.E.C.)
| | - Mary Bronner
- Department of Pathology, Division of Microbiology and Immunology, University of Utah School of Medicine, Salt Lake City, UT 84132, USA; (K.A.K.); (R.B.); (X.J.); (A.S.); (M.B.); (J.L.R.)
- Huntsman Cancer Institute, Salt Lake City, UT 84112, USA
| | - James E. Cox
- Metabolomics Core Research Facility, University of Utah, Salt Lake City, UT 84112, USA; (J.A.M.); (J.E.C.)
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - June L. Round
- Department of Pathology, Division of Microbiology and Immunology, University of Utah School of Medicine, Salt Lake City, UT 84132, USA; (K.A.K.); (R.B.); (X.J.); (A.S.); (M.B.); (J.L.R.)
| | - Diane M. Ward
- Department of Pathology, Division of Microbiology and Immunology, University of Utah School of Medicine, Salt Lake City, UT 84132, USA; (K.A.K.); (R.B.); (X.J.); (A.S.); (M.B.); (J.L.R.)
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Iron depletion attenuates steatosis in a mouse model of non-alcoholic fatty liver disease: Role of iron-dependent pathways. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166142. [PMID: 33839281 DOI: 10.1016/j.bbadis.2021.166142] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 03/23/2021] [Accepted: 04/01/2021] [Indexed: 02/06/2023]
Abstract
BACKGROUND & AIMS Iron has been proposed as influencing the progression of liver disease in subjects with non-alcoholic fatty liver disease (NAFLD). We have previously shown that, in the Hfe-/- mouse model of hemochromatosis, feeding of a high-calorie diet (HCD) leads to increased liver injury. In this study we investigated whether the feeding of an iron deficient/HCD to Hfe-/- mice influenced the development of NAFLD. METHODS Liver histology was assessed in Hfe-/- mice fed a standard iron-containing or iron-deficient diet plus or minus a HCD. Hepatic iron concentration, serum transferrin saturation and free fatty acid were measured. Expression of genes implicated in iron regulation and fatty liver disease was determined by quantitative real-time PCR (qRT-PCR). RESULTS Standard iron/HCD-fed mice developed severe steatosis whereas NAS score was reduced in mice fed iron-deficient HCD. Mice fed iron-deficient HCD had lower liver weights, lower transferrin saturation and decreased ferroportin and hepcidin gene expression than HCD-fed mice. Serum non-esterified fatty acids were increased in iron-deficient HCD-fed mice compared with standard iron HCD. Expression analysis indicated that genes involved in fatty-acid binding and mTOR pathways were regulated by iron depletion. CONCLUSIONS Our results indicate that decreasing iron intake attenuates the development of steatosis resulting from a high calorie diet. These results also suggest that human studies of agents that modify iron balance in patients with NAFLD should be revisited.
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Britton L, Bridle K, Jaskowski LA, He J, Ng C, Ruelcke JE, Mohamed A, Reiling J, Santrampurwala N, Hill MM, Whitehead JP, Subramaniam VN, Crawford DH. Iron Inhibits the Secretion of Apolipoprotein E in Cultured Human Adipocytes. Cell Mol Gastroenterol Hepatol 2018; 6:215-217.e8. [PMID: 30105281 PMCID: PMC6085534 DOI: 10.1016/j.jcmgh.2018.04.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 04/02/2018] [Indexed: 12/11/2022]
Affiliation(s)
- L.J. Britton
- Gallipoli Medical Research Institute, Greenslopes Private Hospital, Greenslopes, Queensland, Australia
- Faculty of Medicine, The University of Queensland, Herston, Queensland, Australia
- Department of Gastroenterology, Princess Alexandra Hospital, Queensland, Australia
- Mater Research, Translational Research Institute, Woolloongabba, Queensland, Australia
| | - Kim Bridle
- Gallipoli Medical Research Institute, Greenslopes Private Hospital, Greenslopes, Queensland, Australia
- Faculty of Medicine, The University of Queensland, Herston, Queensland, Australia
| | - Lesley-Anne Jaskowski
- Gallipoli Medical Research Institute, Greenslopes Private Hospital, Greenslopes, Queensland, Australia
- Faculty of Medicine, The University of Queensland, Herston, Queensland, Australia
| | - Jingjing He
- Mater Research, Translational Research Institute, Woolloongabba, Queensland, Australia
| | - Choaping Ng
- Mater Research, Translational Research Institute, Woolloongabba, Queensland, Australia
- School of Life Sciences, University of Lincoln, Lincoln, United Kingdom
| | - Jayde E. Ruelcke
- The University of Queensland Diamantina Institute, Faculty of Medicine, University of Queensland, Queensland, Australia
| | - Ahmed Mohamed
- The University of Queensland Diamantina Institute, Faculty of Medicine, University of Queensland, Queensland, Australia
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Janske Reiling
- Gallipoli Medical Research Institute, Greenslopes Private Hospital, Greenslopes, Queensland, Australia
- Faculty of Medicine, The University of Queensland, Herston, Queensland, Australia
- Department of Surgery, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
| | - Nishreen Santrampurwala
- Gallipoli Medical Research Institute, Greenslopes Private Hospital, Greenslopes, Queensland, Australia
- Faculty of Medicine, The University of Queensland, Herston, Queensland, Australia
| | - Michelle M. Hill
- The University of Queensland Diamantina Institute, Faculty of Medicine, University of Queensland, Queensland, Australia
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Jonathan P. Whitehead
- Mater Research, Translational Research Institute, Woolloongabba, Queensland, Australia
- School of Life Sciences, University of Lincoln, Lincoln, United Kingdom
| | - V. Nathan Subramaniam
- Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Queensland University of Technology, Kelvin Grove, Queensland, Australia
| | - Darrell H.G. Crawford
- Gallipoli Medical Research Institute, Greenslopes Private Hospital, Greenslopes, Queensland, Australia
- Faculty of Medicine, The University of Queensland, Herston, Queensland, Australia
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Ferroportin Expression in Adipocytes Does Not Contribute to Iron Homeostasis or Metabolic Responses to a High Calorie Diet. Cell Mol Gastroenterol Hepatol 2018; 5:319-331. [PMID: 29552621 PMCID: PMC5852331 DOI: 10.1016/j.jcmgh.2018.01.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 01/03/2018] [Indexed: 01/09/2023]
Abstract
BACKGROUND & AIMS Iron has an increasingly recognized role in the regulation of adipose tissue function, including the expression of adipokines involved in the pathogenesis of nonalcoholic fatty liver disease. The cellular iron exporter, ferroportin, has been proposed as being a key determinant of adipocyte iron homeostasis. METHODS We studied an adipocyte-specific ferroportin (Fpn1) knockout mouse model, using an Adipoq-Cre recombinase driven Fpn1 deletion and fed mice according to the fast food diet model of nonalcoholic steatohepatitis. RESULTS We showed successful selective deletion of Fpn1 in adipocytes, but found that this did not lead to increased adipocyte iron stores as measured by atomic absorption spectroscopy or histologically quantified iron granules after staining with 3,3'-diaminobenzidine-enhanced Perls' stain. Mice with adipocyte-specific Fpn1 deletion did not show dysregulation of adiponectin, leptin, resistin, or retinol-binding protein-4 expression. Similarly, adipocyte-specific Fpn1 deletion did not affect insulin sensitivity during hyperinsulinemic-euglycemic clamp studies or lead to histologic evidence of increased liver injury. We have shown, however, that the fast food diet model of nonalcoholic steatohepatitis generates an increase in adipose tissue macrophage infiltration with crown-like structures, as seen in human beings, further validating the utility of this model. CONCLUSIONS Ferroportin may not be a key determinant of adipocyte iron homeostasis in this knockout model. Further studies are needed to determine the mechanisms of iron metabolism in adipocytes and adipose tissue.
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Key Words
- AAS, atomic absorption spectroscopy
- ANOVA, analysis of variance
- AUC, area under the curve
- Adipoq, adiponectin
- Adipose Tissue
- EFP, epididymal fat pad
- FKO, ferroportin knockout
- Ferroportin
- Ferroportin Flox, Fpn1fl/fl
- Fpn1, ferroportin
- HIC, hepatic iron concentration
- Hamp1, hepcidin
- Iron
- NAFLD, nonalcoholic fatty liver disease
- NASH, nonalcoholic steatohepatitis
- Nonalcoholic Fatty Liver Disease
- PCR, polymerase chain reaction
- RBP-4, retinol binding protein-4
- Tfr1, transferrin receptor-1
- bp, base pair
- cDNA, complementary DNA
- mRNA, messenger RNA
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Zhang YY, Gong JP, Li ZM. Autophagy and hepatic lipid metabolism. Shijie Huaren Xiaohua Zazhi 2017; 25:491-497. [DOI: 10.11569/wcjd.v25.i6.491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Autophagy is initially thought to be a non-selective process in which intracellular proteins or damaged organelles are degraded. It is activated when cells lack nutrients and energy. Autophagy degrades cytoplasmic components within lysosomes and reuses the energy of amino acids to promote cell survival and maintain the cytoplasmic content. Current evidence implicates autophagy in the regulation of lipid stores within the two main organs involved in maintaining lipid homeostasis, the liver and adipose tissue. Upregulation of autophagy may lead to conversion of white adipose tissue into brown adipose tissue, thus regulating energy expenditure and obesity. Discovering new therapeutic interventions to treat lipid and lipoprotein disorders is of great interest and the discovery of autophagy as a regulator of lipid metabolism has opened up a new avenue for this area. In the liver, autophagy can play a role in some common metabolic disorders, which needs further research.
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Britton L, Jaskowski L, Bridle K, Santrampurwala N, Reiling J, Musgrave N, Subramaniam VN, Crawford D. Heterozygous Hfe gene deletion leads to impaired glucose homeostasis, but not liver injury in mice fed a high-calorie diet. Physiol Rep 2016; 4:4/12/e12837. [PMID: 27354540 PMCID: PMC4923236 DOI: 10.14814/phy2.12837] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Accepted: 05/26/2016] [Indexed: 12/30/2022] Open
Abstract
Heterozygous mutations of the Hfe gene have been proposed as cofactors in the development and progression of nonalcoholic fatty liver disease (NAFLD). Homozygous Hfe deletion previously has been shown to lead to dysregulated hepatic lipid metabolism and accentuated liver injury in a dietary mouse model of NAFLD. We sought to establish whether heterozygous deletion of Hfe is sufficient to promote liver injury when mice are exposed to a high‐calorie diet (HCD). Eight‐week‐old wild‐type and Hfe+/− mice received 8 weeks of a control diet or HCD. Liver histology and pathways of lipid and iron metabolism were analyzed. Liver histology demonstrated that mice fed a HCD had increased NAFLD activity score (NAS), steatosis, and hepatocyte ballooning. However, liver injury was unaffected by Hfe genotype. Hepatic iron concentration (HIC) was increased in Hfe+/− mice of both dietary groups. HCD resulted in a hepcidin‐independent reduction in HIC. Hfe+/− mice demonstrated raised fasting serum glucose concentrations and HOMA‐IR score, despite unaltered serum adiponectin concentrations. Downstream regulators of hepatic de novo lipogenesis (pAKT, SREBP‐1, Fas, Scd1) and fatty acid oxidation (AdipoR2, Pparα, Cpt1) were largely unaffected by genotype. In summary, heterozygous Hfe gene deletion is associated with impaired iron and glucose metabolism. However, unlike homozygous Hfe deletion, heterozygous gene deletion did not affect lipid metabolism pathways or liver injury in this model.
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Affiliation(s)
- Laurence Britton
- Gallipoli Medical Research Institute, Greenslopes Private Hospital, Greenslopes, Queensland, Australia The School of Medicine, University of Queensland, Herston, Queensland, Australia The Department of Gastroenterology, Princess Alexandra Hospital, Woolloongabba, Queensland, Australia QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Lesley Jaskowski
- Gallipoli Medical Research Institute, Greenslopes Private Hospital, Greenslopes, Queensland, Australia The School of Medicine, University of Queensland, Herston, Queensland, Australia QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Kim Bridle
- Gallipoli Medical Research Institute, Greenslopes Private Hospital, Greenslopes, Queensland, Australia The School of Medicine, University of Queensland, Herston, Queensland, Australia
| | - Nishreen Santrampurwala
- Gallipoli Medical Research Institute, Greenslopes Private Hospital, Greenslopes, Queensland, Australia The School of Medicine, University of Queensland, Herston, Queensland, Australia QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Janske Reiling
- Gallipoli Medical Research Institute, Greenslopes Private Hospital, Greenslopes, Queensland, Australia The School of Medicine, University of Queensland, Herston, Queensland, Australia Department of Surgery, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
| | - Nick Musgrave
- Sullivan and Nicolaides Pathology, Greenslopes Private Hospital, Greenslopes, Queensland, Australia
| | | | - Darrell Crawford
- Gallipoli Medical Research Institute, Greenslopes Private Hospital, Greenslopes, Queensland, Australia The School of Medicine, University of Queensland, Herston, Queensland, Australia
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