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Heinitz S, Traurig M, Krakoff J, Rabe P, Stäubert C, Kobes S, Hanson RL, Stumvoll M, Blüher M, Bogardus C, Baier L, Piaggi P. An E115A Missense Variant in CERS2 Is Associated With Increased Sleeping Energy Expenditure and Hepatic Insulin Resistance in American Indians. Diabetes 2024; 73:1361-1371. [PMID: 38776413 PMCID: PMC11262042 DOI: 10.2337/db23-0690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 05/20/2024] [Indexed: 05/25/2024]
Abstract
Genetic determinants of interindividual differences in energy expenditure (EE) are largely unknown. Sphingolipids, such as ceramides, have been implicated in the regulation of human EE via mitochondrial uncoupling. In this study, we investigated whether genetic variants within enzymes involved in sphingolipid synthesis and degradation affect EE and insulin-related traits in a cohort of American Indians informative for 24-h EE and glucose disposal rates during a hyperinsulinemic-euglycemic clamp. Association analysis of 10,084 genetic variants within 28 genes involved in sphingolipid pathways identified a missense variant (rs267738, A>C, E115A) in exon 4 of CERS2 that was associated with higher sleeping EE (116 kcal/day) and increased rates of endogenous glucose production during basal (5%) and insulin-stimulated (43%) conditions, both indicators of hepatic insulin resistance. The rs267738 variant did not affect ceramide synthesis in HepG2 cells but resulted in a 30% decrease in basal mitochondrial respiration. In conclusion, we provide evidence that the CERS2 rs267738 missense variant may influence hepatic glucose production and postabsorptive sleeping metabolic rate. ARTICLE HIGHLIGHTS
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Affiliation(s)
- Sascha Heinitz
- Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, AZ
- Department of Internal Medicine, Clinic for Endocrinology, Nephrology and Rheumatology, University of Leipzig, Leipzig, Germany
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig, Philipp-Rosenthal-Strasse 27, Leipzig, Germany
| | - Michael Traurig
- Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, AZ
| | - Jonathan Krakoff
- Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, AZ
| | - Philipp Rabe
- Faculty of Medicine, Rudolf Schönheimer Institute of Biochemistry, Leipzig University, Leipzig, Germany
| | - Claudia Stäubert
- Faculty of Medicine, Rudolf Schönheimer Institute of Biochemistry, Leipzig University, Leipzig, Germany
| | - Sayuko Kobes
- Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, AZ
| | - Robert L. Hanson
- Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, AZ
| | - Michael Stumvoll
- Department of Internal Medicine, Clinic for Endocrinology, Nephrology and Rheumatology, University of Leipzig, Leipzig, Germany
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig, Philipp-Rosenthal-Strasse 27, Leipzig, Germany
| | - Matthias Blüher
- Department of Internal Medicine, Clinic for Endocrinology, Nephrology and Rheumatology, University of Leipzig, Leipzig, Germany
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig, Philipp-Rosenthal-Strasse 27, Leipzig, Germany
| | - Clifton Bogardus
- Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, AZ
| | - Leslie Baier
- Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, AZ
| | - Paolo Piaggi
- Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, AZ
- Department of Information Engineering, University of Pisa, Pisa, Italy
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Zhang C, Steadman M, Santos HP, Shaikh SR, Xavier RM. GPAT1 Activity and Abundant Palmitic Acid Impair Insulin Suppression of Hepatic Glucose Production in Primary Mouse Hepatocytes. J Nutr 2024; 154:1109-1118. [PMID: 38354952 PMCID: PMC11007742 DOI: 10.1016/j.tjnut.2024.02.004] [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: 08/08/2023] [Revised: 01/31/2024] [Accepted: 02/07/2024] [Indexed: 02/16/2024] Open
Abstract
BACKGROUND Glycerol-3-phosphate acyltransferase (GPAT) activity is correlated with obesity and insulin resistance in mice and humans. However, insulin resistance exists in people with normal body weight, and individuals with obesity may be metabolically healthy, implying the presence of complex pathophysiologic mechanisms underpinning insulin resistance. OBJECTIVE We asked what conditions related to GPAT1 must be met concurrently for hepatic insulin resistance to occur. METHODS Mouse hepatocytes were overexpressed with GPATs via adenoviral infection or exposed to high or low concentrations of glucose. Glucose production by the cells and phosphatidic acid (PA) content in the cells were assayed, GPAT activity was measured, relative messenger RNA expressions of sterol-regulatory element-binding protein 1c (SREBP1c), carbohydrate response element-binding protein (ChREBP), and GPAT1 were analyzed, and insulin signaling transduction was examined. RESULTS Overexpressing GPAT1 in mouse hepatocytes impaired insulin's suppression of glucose production, together with an increase in both N-ethylmaleimide-resistant GPAT activity and the content of di-16:0 PA. Akt-mediated insulin signaling was inhibited in hepatocytes that overexpressed GPAT1. When the cells were exposed to high-glucose concentrations, insulin suppression of glucose production was impaired, and adding palmitic acid exacerbated this impairment. High-glucose exposure increased the expression of SREBP1c, ChREBP, and GPAT1 by ∼2-, 5-, and 5.7-fold, respectively. The addition of 200 mM palmitic acid or linoleic acid to the culture media did not change the upregulation of expression of these genes by high glucose. High-glucose exposure increased di-16:0 PA content in the cells, and adding palmitic acid further increased di-16:0 PA content. The effect was specific to palmitic acid because linoleic acid did not show these effects. CONCLUSION These data demonstrate that high-GPAT1 activity, whether induced by glucose exposure or acquired by transfection, and abundant palmitic acid can impair insulin's ability to suppress hepatic glucose production in primary mouse hepatocytes.
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Affiliation(s)
- Chongben Zhang
- Biobehavioral Laboratory, School of Nursing, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States.
| | - Mathew Steadman
- Biobehavioral Laboratory, School of Nursing, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Hudson P Santos
- School of Nursing and Health Studies, University of Miami, Coral Gables, FL, United States
| | - Saame R Shaikh
- Department of Nutrition, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Rose Mary Xavier
- Biobehavioral Laboratory, School of Nursing, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States.
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Ramanathan R, Patwa SA, Ali AH, Ibdah JA. Thyroid Hormone and Mitochondrial Dysfunction: Therapeutic Implications for Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD). Cells 2023; 12:2806. [PMID: 38132126 PMCID: PMC10741470 DOI: 10.3390/cells12242806] [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: 10/23/2023] [Revised: 11/30/2023] [Accepted: 12/07/2023] [Indexed: 12/23/2023] Open
Abstract
Metabolic dysfunction-associated steatotic liver disease (MASLD), formerly termed nonalcoholic fatty liver disease (NAFLD), is a widespread global health concern that affects around 25% of the global population. Its influence is expanding, and it is anticipated to overtake alcohol as the leading cause of liver failure and liver-related death worldwide. Unfortunately, there are no approved therapies for MASLD; as such, national and international regulatory health agencies undertook strategies and action plans designed to expedite the development of drugs for treatment of MASLD. A sedentary lifestyle and an unhealthy diet intake are important risk factors. Western countries have a greater estimated prevalence of MASLD partly due to lifestyle habits. Mitochondrial dysfunction is strongly linked to the development of MASLD. Further, it has been speculated that mitophagy, a type of mitochondrial quality control, may be impaired in MASLD. Thyroid hormone (TH) coordinates signals from the nuclear and mitochondrial genomes to control mitochondrial biogenesis and function in hepatocytes. Mitochondria are known TH targets, and preclinical and clinical studies suggest that TH, thyroid receptor β (TR-β) analogs, and synthetic analogs specific to the liver could be of therapeutic benefit in treating MASLD. In this review, we highlight how mitochondrial dysfunction contributes to development of MASLD, and how understanding the role of TH in improving mitochondrial function paved the way for innovative drug development programs of TH-based therapies targeting MASLD.
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Affiliation(s)
- Raghu Ramanathan
- Division of Gastroenterology and Hepatology, University of Missouri, Columbia, MO 65212, USA; (R.R.); (A.H.A.)
- Harry S. Truman Memorial Veterans Medical Center, University of Missouri, Columbia, MO 65212, USA
| | - Sohum A. Patwa
- Division of Gastroenterology and Hepatology, University of Missouri, Columbia, MO 65212, USA; (R.R.); (A.H.A.)
| | - Ahmad Hassan Ali
- Division of Gastroenterology and Hepatology, University of Missouri, Columbia, MO 65212, USA; (R.R.); (A.H.A.)
- Harry S. Truman Memorial Veterans Medical Center, University of Missouri, Columbia, MO 65212, USA
| | - Jamal A. Ibdah
- Division of Gastroenterology and Hepatology, University of Missouri, Columbia, MO 65212, USA; (R.R.); (A.H.A.)
- Harry S. Truman Memorial Veterans Medical Center, University of Missouri, Columbia, MO 65212, USA
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO 65212, USA
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Lee GB, Huh Y, Lee SH, Han B, Kim YH, Kim DH, Kim SM, Choi YS, Cho KH, Nam GE. Association of low muscle strength with metabolic dysfunction-associated fatty liver disease: A nationwide study. World J Gastroenterol 2023; 29:5962-5973. [PMID: 38131000 PMCID: PMC10731149 DOI: 10.3748/wjg.v29.i45.5962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 10/30/2023] [Accepted: 11/17/2023] [Indexed: 12/01/2023] Open
Abstract
BACKGROUND There is limited evidence regarding the association between muscle strength and metabolic dysfunction-associated fatty liver disease (MAFLD). AIM To investigate the association between muscle strength and MAFLD in the general population in Korea. METHODS This nationwide representative cross-sectional study included 31649 individuals aged ≥ 19 years who participated in the Korea National Health and Nutrition Examination Survey between 2015 and 2018. Odds ratios (ORs) and 95% confidence intervals (95%CIs) for MAFLD according to sex-specific quartiles of muscle strength, defined by relative handgrip strength, were calculated using multivariable logistic regression analysis. Additionally, multivariable logistic regression analysis was used to assess the association between muscle strength and probable liver fibrosis in patients with MAFLD. RESULTS Of all the participants, 29.3% had MAFLD. The prevalence of MAFLD was significantly higher in the lower muscle strength quartile groups for all participants, sexes, and age groups (P < 0.001). A 1.92-fold (OR = 1.92, 95%CI: 1.70-2.16) and 3.12-fold (OR = 3.12, 95%CI: 2.64-3.69) higher risk of MAFLD was observed in the lowest quartile (Q1) group than in the other groups (Q2-Q4) and the highest quartile (Q4) group, respectively. The ORs of MAFLD were significantly increased in the lower muscle strength quartile groups in a dose-dependent manner (P for trend < 0.001). These associations persisted in both sexes. An inverse association between muscle strength and the risk of MAFLD was observed in all subgroups according to age, obesity, and diabetes mellitus. In patients with MAFLD, the odds of severe liver fibrosis were higher in Q1 (OR = 1.83, 95%CI: 1.25-2.69) than in other groups (Q2-Q4). CONCLUSION Among Korean adults, low muscle strength was associated with an increased risk of MAFLD and liver fibrosis in patients with MAFLD.
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Affiliation(s)
- Gyu Bae Lee
- Department of Family Medicine, Korea University College of Medicine, Seoul 02841, South Korea
| | - Youn Huh
- Department of Family Medicine, Uijeongbu Eulji Medical Center, EULJI University, Daejeon 11759, South Korea
| | - Sang Hyun Lee
- School of Electrical Engineering, Korea University, Seoul 02841, South Korea
| | - Byoungduck Han
- Department of Family Medicine, Korea University College of Medicine, Seoul 02841, South Korea
| | - Yang-Hyun Kim
- Department of Family Medicine, Korea University College of Medicine, Seoul 02841, South Korea
| | - Do-Hoon Kim
- Department of Family Medicine, Korea University College of Medicine, Seoul 02841, South Korea
| | - Seon Mee Kim
- Department of Family Medicine, Korea University College of Medicine, Seoul 02841, South Korea
| | - Youn Seon Choi
- Department of Family Medicine, Korea University College of Medicine, Seoul 02841, South Korea
| | - Kyung Hwan Cho
- Department of Family Medicine, Korea University College of Medicine, Seoul 02841, South Korea
| | - Ga Eun Nam
- Department of Family Medicine, Korea University College of Medicine, Seoul 02841, South Korea
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Zhang T, Nie Y, Wang J. The emerging significance of mitochondrial targeted strategies in NAFLD treatment. Life Sci 2023; 329:121943. [PMID: 37454757 DOI: 10.1016/j.lfs.2023.121943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 07/04/2023] [Accepted: 07/12/2023] [Indexed: 07/18/2023]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease worldwide, ranging from liver steatosis to nonalcoholic steatohepatitis, which ultimately progresses to fibrosis, cirrhosis, and hepatocellular carcinoma. Individuals with NAFLD have a higher risk of developing cardiovascular and extrahepatic cancers. Despite the great progress being made in understanding the pathogenesis and the introduction of new pharmacological targets for NAFLD, no drug or intervention has been accepted for its management. Recent evidence suggests that NAFLD may be a mitochondrial disease, as mitochondrial dysfunction is involved in the pathological processes that lead to NAFLD. In this review, we describe the recent advances in our understanding of the mechanisms associated with mitochondrial dysfunction in NAFLD progression. Moreover, we discuss recent advances in the efficacy of mitochondria-targeted compounds (e.g., Mito-Q, MitoVit-E, MitoTEMPO, SS-31, mitochondrial uncouplers, and mitochondrial pyruvate carrier inhibitors) for treating NAFLD. Furthermore, we present some medications currently being tested in clinical trials for NAFLD treatment, such as exercise, mesenchymal stem cells, bile acids and their analogs, and antidiabetic drugs, with a focus on their efficacy in improving mitochondrial function. Based on this evidence, further investigations into the development of mitochondria-based agents may provide new and promising alternatives for NAFLD management.
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Affiliation(s)
- Tao Zhang
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Key Laboratory of Anesthesiology and Resuscitation (Huazhong University of Science and Technology), Ministry of Education, China; Institute of Anesthesia and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
| | - Yingli Nie
- Department of Dermatology, Wuhan Children's Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430014, China.
| | - Jiliang Wang
- Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
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Mucinski JM, Perry AM, Fordham TM, Diaz-Arias A, Ibdah JA, Rector RS, Parks EJ. Labeled breath tests in patients with NASH: Octanoate oxidation relates best to measures of glucose metabolism. Front Physiol 2023; 14:1172675. [PMID: 37153214 PMCID: PMC10160408 DOI: 10.3389/fphys.2023.1172675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 04/11/2023] [Indexed: 05/09/2023] Open
Abstract
In vivo methods to estimate human liver mitochondrial activity are lacking and this project's goal was to use a non-invasive breath test to quantify complete mitochondrial fat oxidation and determine how test results changed when liver disease state was altered over time. Patients with suspected non-alcoholic fatty liver disease (NAFLD; 9 men, 16 women, 47 ± 10 years, 113 ± 23 kg) underwent a diagnostic liver biopsy and liver tissue was histologically scored by a pathologist using the NAFLD activity score (0-8). To assess liver oxidation activity, a labeled medium chain fatty acid was consumed orally (23.4 mg 13C4-octanoate) and breath samples collected over 135 min. Total CO2 production rates were measured using breath 13CO2 analysis by isotope ratio mass spectrometry. Fasting endogenous glucose production (EGP) was measured using an IV infusion of 13C6-glucose. At baseline, subjects oxidized 23.4 ± 3.9% (14.9%-31.5%) of the octanoate dose and octanoate oxidation (OctOx) was negatively correlated with fasting plasma glucose (r = -0.474, p = 0.017) and EGP (r = -0.441, p = 0.028). Twenty-two subjects returned for repeat tests 10.2 ± 1.0 months later, following lifestyle treatment or standardized care. OctOx (% dose/kg) was significantly greater across all subjects (p = 0.044), negatively related to reductions in EGP (r = -0.401, p = 0.064), and tended to correlate with reduced fasting glucose (r = -0.371, p = 0.090). Subjects exhibited reductions in steatosis (p = 0.007) which tended to correlate with increased OctOx (% of dose/kg, r = -0.411, p = 0.058). Based on our findings, the use of an 13C-octanoate breath test may be an indicator of hepatic steatosis and glucose metabolism, but these relationships require verification through larger studies in NAFLD populations.
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Affiliation(s)
- Justine M. Mucinski
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, United States
| | - Alisha M. Perry
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, United States
| | - Talyia M. Fordham
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, United States
| | - Alberto Diaz-Arias
- Boyce & Bynum Pathology Professional Services, Columbia, MO, United States
| | - Jamal A. Ibdah
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Missouri School of Medicine, Columbia, MO, United States
- Research Service, Harry S. Truman Memorial Veterans Medical Center, Columbia, MO, United States
| | - R. Scott Rector
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, United States
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Missouri School of Medicine, Columbia, MO, United States
- Research Service, Harry S. Truman Memorial Veterans Medical Center, Columbia, MO, United States
- NextGen Precision Health, University of Missouri, Columbia, MO, United States
| | - Elizabeth J. Parks
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, United States
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Missouri School of Medicine, Columbia, MO, United States
- NextGen Precision Health, University of Missouri, Columbia, MO, United States
- *Correspondence: Elizabeth J. Parks,
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Moore MP, Cunningham RP, Meers GM, Johnson SA, Wheeler AA, Ganga RR, Spencer NM, Pitt JB, Diaz-Arias A, Swi AIA, Hammoud GM, Ibdah JA, Parks EJ, Rector RS. Compromised hepatic mitochondrial fatty acid oxidation and reduced markers of mitochondrial turnover in human NAFLD. Hepatology 2022; 76:1452-1465. [PMID: 35000203 PMCID: PMC9270503 DOI: 10.1002/hep.32324] [Citation(s) in RCA: 86] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND AIMS NAFLD and its more-advanced form, steatohepatitis (NASH), is associated with obesity and is an independent risk factor for cardiovascular, liver-related, and all-cause mortality. Available human data examining hepatic mitochondrial fatty acid oxidation (FAO) and hepatic mitochondrial turnover in NAFLD and NASH are scant. APPROACH AND RESULTS To investigate this relationship, liver biopsies were obtained from patients with obesity undergoing bariatric surgery and data clustered into four groups based on hepatic histopathological classification: Control (CTRL; no disease); NAFL (steatosis only); Borderline-NASH (steatosis with lobular inflammation or hepatocellular ballooning); and Definite-NASH (D-NASH; steatosis, lobular inflammation, and hepatocellular ballooning). Hepatic mitochondrial complete FAO to CO2 and the rate-limiting enzyme in β-oxidation (β-hydroxyacyl-CoA dehydrogenase activity) were reduced by ~40%-50% with D-NASH compared with CTRL. This corresponded with increased hepatic mitochondrial reactive oxygen species production, as well as dramatic reductions in markers of mitochondrial biogenesis, autophagy, mitophagy, fission, and fusion in NAFL and NASH. CONCLUSIONS These findings suggest that compromised hepatic FAO and mitochondrial turnover are intimately linked to increasing NAFLD severity in patients with obesity.
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Affiliation(s)
- Mary P. Moore
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, MO, USA, 65201
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, USA, 65211
| | - Rory P. Cunningham
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, MO, USA, 65201
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, USA, 65211
| | - Grace M. Meers
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, MO, USA, 65201
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, USA, 65211
| | - Sarah A. Johnson
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, MO, USA, 65201
- Department of Medicine-Division of Gastroenterology and Hepatology, University of Missouri, Columbia MO, USA, 65211
| | - Andrew A. Wheeler
- Department of Surgery, University of Missouri, Columbia MO, USA, 65211
| | - Rama R. Ganga
- Department of Surgery, University of Missouri, Columbia MO, USA, 65211
| | - Nicole M. Spencer
- Department of Surgery, University of Missouri, Columbia MO, USA, 65211
| | - James B. Pitt
- Department of Surgery, University of Missouri, Columbia MO, USA, 65211
| | | | - Ahmed I. A. Swi
- Department of Medicine-Division of Gastroenterology and Hepatology, University of Missouri, Columbia MO, USA, 65211
| | - Ghassan M. Hammoud
- Department of Medicine-Division of Gastroenterology and Hepatology, University of Missouri, Columbia MO, USA, 65211
| | - Jamal A. Ibdah
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, MO, USA, 65201
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, USA, 65211
- Department of Medicine-Division of Gastroenterology and Hepatology, University of Missouri, Columbia MO, USA, 65211
| | - Elizabeth J. Parks
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, USA, 65211
- Department of Medicine-Division of Gastroenterology and Hepatology, University of Missouri, Columbia MO, USA, 65211
| | - R. Scott Rector
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, MO, USA, 65201
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, USA, 65211
- Department of Medicine-Division of Gastroenterology and Hepatology, University of Missouri, Columbia MO, USA, 65211
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Valenzuela-Vallejo L, Mantzoros CS. Time to transition from a negative nomenclature describing what NAFLD is not, to a novel, pathophysiology-based, umbrella classification of fatty liver disease (FLD). Metabolism 2022; 134:155246. [PMID: 35780909 DOI: 10.1016/j.metabol.2022.155246] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 06/21/2022] [Accepted: 06/22/2022] [Indexed: 12/14/2022]
Abstract
Non-alcoholic fatty liver disease (NAFLD) is a definition of a prevalent condition that has been given a name describing what the disease is not, mainly due to gaps in the physiopathological understanding of NAFLD when the name was given to it. NAFLD still remains an unmet clinical need to a large extent due to the heterogenicity of the disease and the lack of a more accurate physiology-based classification. In essence, fatty liver disease (FLD) has a multifactorial etiology, including metabolic abnormalities, environmental influences, genetic disorders, and/or their overlap which makes it difficult to diagnose, design appropriate trials for it and treat this disease. Therefore, we propose herein that as our knowledge about this disease continues to grow exponentially, it is time to consider ending this unspecific, negative and broad classification of NAFLD, and turn it into a positive and targeted one describing what the disease is and not what it is not. Thus, we propose the novel FLD "Mantzoros classification". This innovative classification proposes to classify the heterogeneous causes of FLD under one umbrella and eventually lead to a better nomenclature and classification system reflecting pathophysiology. This in turn could lead to both better clinical trials and more personalized care. An additional aim is to generate a dialogue among the experts in this field to eventually reach the right nomenclature for an appropriate disease classification that would facilitate our understanding, approach, diagnosis, and management of this epidemic of FLD. Overall, a novel classification, based on phenotypic manifestations, leading risk factors and probable causes of FLD, could help our understanding and clinically would be accurately defining and differentiating the disease, leading to a more accurate design and execution of clinical trials. This would in turn lead to tangible benefits for all patients suffering from FLD through targeted and more effective personalized treatments.
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Affiliation(s)
- Laura Valenzuela-Vallejo
- Department of Medicine, Beth-Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, United States
| | - Christos S Mantzoros
- Department of Medicine, Beth-Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, United States; Department of Medicine, Boston VA Healthcare System, Boston, MA 02130, United States.
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9
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Ramanathan R, Ali AH, Ibdah JA. Mitochondrial Dysfunction Plays Central Role in Nonalcoholic Fatty Liver Disease. Int J Mol Sci 2022; 23:ijms23137280. [PMID: 35806284 PMCID: PMC9267060 DOI: 10.3390/ijms23137280] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 06/27/2022] [Accepted: 06/29/2022] [Indexed: 12/04/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is a global pandemic that affects one-quarter of the world’s population. NAFLD includes a spectrum of progressive liver disease from steatosis to nonalcoholic steatohepatitis (NASH), fibrosis, and cirrhosis and can be complicated by hepatocellular carcinoma. It is strongly associated with metabolic syndromes, obesity, and type 2 diabetes, and it has been shown that metabolic dysregulation is central to its pathogenesis. Recently, it has been suggested that metabolic- (dysfunction) associated fatty liver disease (MAFLD) is a more appropriate term to describe the disease than NAFLD, which puts increased emphasis on the important role of metabolic dysfunction in its pathogenesis. There is strong evidence that mitochondrial dysfunction plays a significant role in the development and progression of NAFLD. Impaired mitochondrial fatty acid oxidation and, more recently, a reduction in mitochondrial quality, have been suggested to play a major role in NAFLD development and progression. In this review, we provide an overview of our current understanding of NAFLD and highlight how mitochondrial dysfunction contributes to its pathogenesis in both animal models and human subjects. Further we discuss evidence that the modification of mitochondrial function modulates NAFLD and that targeting mitochondria is a promising new avenue for drug development to treat NAFLD/NASH.
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Affiliation(s)
- Raghu Ramanathan
- Division of Gastroenterology and Hepatology, University of Missouri, Columbia, MO 65212, USA; (R.R.); (A.H.A.)
- Harry S. Truman Memorial Veterans Medical Center, Columbia, MO 65201, USA
| | - Ahmad Hassan Ali
- Division of Gastroenterology and Hepatology, University of Missouri, Columbia, MO 65212, USA; (R.R.); (A.H.A.)
- Harry S. Truman Memorial Veterans Medical Center, Columbia, MO 65201, USA
| | - Jamal A. Ibdah
- Division of Gastroenterology and Hepatology, University of Missouri, Columbia, MO 65212, USA; (R.R.); (A.H.A.)
- Harry S. Truman Memorial Veterans Medical Center, Columbia, MO 65201, USA
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO 65212, USA
- Correspondence: ; Tel.: +573-882-7349; Fax: +573-884-4595
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10
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Cunningham RP, Moore MP, Dashek RJ, Meers GM, Jepkemoi V, Takahashi T, Vieira-Potter VJ, Kanaley JA, Booth FW, Rector RS. Hepatocyte-specific eNOS deletion impairs exercise-induced adaptations in hepatic mitochondrial function and autophagy. Obesity (Silver Spring) 2022; 30:1066-1078. [PMID: 35357089 PMCID: PMC9050943 DOI: 10.1002/oby.23414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 01/24/2022] [Accepted: 02/11/2022] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Endothelial nitric oxide synthase (eNOS) is a potential mediator of exercise-induced hepatic mitochondrial adaptations. METHODS Here, male and female hepatocyte-specific eNOS knockout (eNOShep-/- ) and intact hepatic eNOS (eNOSfl/fl ) mice performed voluntary wheel-running exercise (EX) or remained in sedentary cage conditions for 10 weeks. RESULTS EX resolved the exacerbated hepatic steatosis in eNOShep-/- male mice. Elevated hydrogen peroxide emission (~50% higher in eNOShep-/- vs. eNOSfl/fl mice) was completely ablated with EX. Interestingly, EX increased [1-14 C] palmitate oxidation in eNOSfl/fl male mice, but this was blunted in the eNOShep-/- male mice. eNOShep-/- mice had lower markers of the energy sensors AMP-activated protein kinase (AMPK)/phospho- (p)AMPK and mammalian target of rapamycin (mTOR) and p-mTOR, as well as the autophagy initiators serine/threonine-protein kinase ULK1 and pULK1, compared with eNOSfl/fl mice. Females showed elevated electron transport chain protein content and markers of mitochondrial biogenesis (transcription factor A, mitochondrial, peroxisome proliferator-activated receptor-gamma coactivator 1α). CONCLUSIONS Collectively, this study demonstrates for the first time, to the authors' knowledge, the requirement of eNOS in hepatocytes in the EX-induced increases in hepatic fatty acid oxidation in male mice. Deletion of eNOS in hepatocytes also appears to impair the energy-sensing ability of the cell and inhibit the activation of the autophagy initiating factor ULK1. These data uncover the important and novel role of hepatocyte eNOS in EX-induced hepatic mitochondrial adaptations.
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Affiliation(s)
- Rory P. Cunningham
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, Missouri 65212, USA
- Nutrition and Exercise Physiology, University of Missouri, Columbia, MO 65211, USA
| | - Mary P. Moore
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, Missouri 65212, USA
- Nutrition and Exercise Physiology, University of Missouri, Columbia, MO 65211, USA
| | - Ryan J. Dashek
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, Missouri 65212, USA
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
| | - Grace M. Meers
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, Missouri 65212, USA
- Nutrition and Exercise Physiology, University of Missouri, Columbia, MO 65211, USA
| | - Vivien Jepkemoi
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, Missouri 65212, USA
| | - Takamune Takahashi
- Division of Nephrology and Hypertension, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| | | | - Jill A. Kanaley
- Nutrition and Exercise Physiology, University of Missouri, Columbia, MO 65211, USA
| | - Frank W. Booth
- Nutrition and Exercise Physiology, University of Missouri, Columbia, MO 65211, USA
- Department of Biomedical Sciences, University of Missouri, Columbia, MO 65211, USA
| | - R. Scott Rector
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, Missouri 65212, USA
- Departments of Medicine-Division of Gastroenterology and Hepatology
- Nutrition and Exercise Physiology, University of Missouri, Columbia, MO 65211, USA
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11
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Wikramanayake TC, Chéret J, Sevilla A, Birch-Machin M, Paus R. Targeting mitochondria in dermatological therapy: Beyond oxidative damage and skin aging. Expert Opin Ther Targets 2022; 26:233-259. [PMID: 35249436 DOI: 10.1080/14728222.2022.2049756] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION The analysis of the role of the mitochondria in oxidative damage and skin aging is a significant aspect of dermatological research. Mitochondria generate most reactive oxygen species (ROS); however, excessive ROS are cytotoxic and DNA-damaging and promote (photo-)aging. ROS also possesses key physiological and regulatory functions and mitochondrial dysfunction is prominent in several skin diseases including skin cancers. Although many standard dermatotherapeutics modulate mitochondrial function, dermatological therapy rarely targets the mitochondria. Accordingly, there is a rationale for "mitochondrial dermatology"-based approaches to be applied to therapeutic research. AREAS COVERED This paper examines the functions of mitochondria in cutaneous physiology beyond energy (ATP) and ROS production. Keratinocyte differentiation and epidermal barrier maintenance, appendage morphogenesis and homeostasis, photoaging and skin cancer are considered. Based on related PubMed search results, the paper evaluates thyroid hormones, glucocorticoids, Vitamin D3 derivatives, retinoids, cannabinoid receptor agonists, PPARγ agonists, thyrotropin, and thyrotropin-releasing hormone as instructive lead compounds. Moreover, the mitochondrial protein MPZL3 as a promising new drug target for future "mitochondrial dermatology" is highlighted. EXPERT OPINION Future dermatological therapeutic research should have a mitochondrial medicine emphasis. Focusing on selected lead agents, protein targets, in silico drug design, and model diseases will fertilize a mito-centric approach.
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Affiliation(s)
- Tongyu C Wikramanayake
- Frost Department of Dermatology & Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL, U.S.A.,Molecular Cell and Developmental Biology Program, University of Miami Miller School of Medicine, Miami, FL, U.S.A
| | - Jérémy Chéret
- Frost Department of Dermatology & Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL, U.S.A
| | - Alec Sevilla
- Frost Department of Dermatology & Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL, U.S.A
| | - Mark Birch-Machin
- Dermatological Sciences, Translational and Clinical Research Institute, and The UK National Innovation Centre for Ageing, Newcastle University, Newcastle upon Tyne, UK
| | - Ralf Paus
- Frost Department of Dermatology & Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL, U.S.A.,Monasterium Laboratory, Münster, Germany.,Centre for Dermatology Research, University of Manchester, and NIHR Manchester Biomedical Research Centre, Manchester, UK
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12
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Bai C, Wang Y, Niu Z, Guan Y, Huang J, Nian X, Zuo F, Zhao J, Kazumi T, Wu B. Exenatide improves hepatocyte insulin resistance induced by different regional adipose tissue. Front Endocrinol (Lausanne) 2022; 13:1012904. [PMID: 36246878 PMCID: PMC9558273 DOI: 10.3389/fendo.2022.1012904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Accepted: 09/15/2022] [Indexed: 11/13/2022] Open
Abstract
Obesity is resulted from energy surplus and is characterized by abnormal adipose tissue accumulation and/or distribution. Adipokines secreted by different regional adipose tissue can induce changes in key proteins of the insulin signaling pathway in hepatocytes and result in impaired hepatic glucose metabolism. This study aimed to investigate whether exenatide affects key proteins of IRS2/PI3K/Akt2 signaling pathway in hepatocytes altered by the different regional fat depots. Six non-obese patients without endocrine diseases were selected as the research subjects. Their subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT)were co-cultured with HepG2 cells in the transwell chamber. In the presence or absence of exenatide, adipokines content in the supernatant of each experimental group was detected by ELISA. In addition, HepG2 cells in each co-culture group with and without insulin were collected, and the expression of key proteins IRS2, p-IRS2(S731), PI3K-p85, Akt2, and p-Akt2(S473) was detected by western blotting (WB). The results showed that the adipokines IL-8, MCP-1, VEGF, and sTNFR2 in the supernatant of HepG2 cells induced by different regional adipose tissue were significantly higher than those in the HepG2 group, and VAT released more adipokines than SAT. Furthermore, these adipokines were significantly inhibited by exenatide. Importantly, the different regional fat depot affects the IRS2/PI3K/Akt2 insulin signaling pathway of hepatocytes. Exenatide can up-regulate the expression of hepatocyte proteins IRS2, PI3K-p85, p-Akt2(S731) inhibited by adipose tissue, and down-regulate the expression of hepatocyte proteins p-IRS2(S731) promoted by adipose tissue. The effect of VAT on the expression of these key proteins in hepatocytes is more significant than that of SAT. But there was no statistical difference in the expression of Akt2 protein among each experimental group, suggesting that exenatide has no influence on the expression of Akt2 protein in hepatocytes. In conclusion, exenatide may improve hepatic insulin resistance (IR) by inhibiting adipokines and regulating the expression of key proteins in the IRS2/PI3K/Akt2 pathway.
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Affiliation(s)
- Chuanmin Bai
- Department of Endocrinology, First Affiliated Hospital, Kunming Medical University, Kunming, China
| | - Yujun Wang
- Department of Endocrinology, First Affiliated Hospital, Kunming Medical University, Kunming, China
| | - Zhi Niu
- Department of Endocrinology, First Affiliated Hospital, Kunming Medical University, Kunming, China
| | - Yaxin Guan
- Department of Endocrinology, First Affiliated Hospital, Kunming Medical University, Kunming, China
| | - Jingshan Huang
- School of Computing, University of South Alabama, Mobile, AL, United States
| | - Xin Nian
- Department of Endocrinology, First Affiliated Hospital, Kunming Medical University, Kunming, China
| | - Fan Zuo
- Department of Endocrinology, First Affiliated Hospital, Kunming Medical University, Kunming, China
| | - Juan Zhao
- Department of Endocrinology, First Affiliated Hospital, Kunming Medical University, Kunming, China
| | - Tsutomu Kazumi
- Open Research Center for Studying of Lifestyle−Related Diseases, Mukogawa Women’s University, Nishinomiya, Japan
- Research Institute for Nutrition Sciences, Mukogawa Women’s University, Nishinomiya, Japan
- Department of Medicine, Kohnan Kakogawa Hospital, Kakogawa, Japan
| | - Bin Wu
- Department of Endocrinology, First Affiliated Hospital, Kunming Medical University, Kunming, China
- *Correspondence: Bin Wu,
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13
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Wang H, Wang J, Zhu Y, Yan H, Lu Y. Effects of Different Intensity Exercise on Glucose Metabolism and Hepatic IRS/PI3K/AKT Pathway in SD Rats Exposed with TCDD. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:13141. [PMID: 34948750 PMCID: PMC8701401 DOI: 10.3390/ijerph182413141] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 12/03/2021] [Accepted: 12/06/2021] [Indexed: 11/17/2022]
Abstract
The objective of the study was to investigate the effects of different intensity exercise and 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) exposure on glucose metabolism in Sprague Dawley (SD) rats, as well as the action of insulin receptor substrate (IRS)/phosphatidylinositol-3-kinases (PI3K)/protein kinase (AKT) signaling pathway in it. Besides that, we explored whether exercise can alleviate the toxicity induced by TCDD. Sixty male SD rats (8 weeks old) were randomly divided into non-exercise group, none-exercise toxic group, moderate-intensity exercise group, moderate-intensity exercise toxic group, high-intensity exercise group, high-intensity exercise toxic group. The toxic groups were intraperitoneally injected with TCDD, which the dose was 6.4 µg/kg· BW for the first week, then 21% of the above week dose for continuous 8 weeks. The 8-week treadmill running of moderate intensity (15 m/min, 60 min/day) and high intensity (26 m/min, 35 min/day) were implemented separately in exercise groups five times a week. After detecting the concentration of fasting serum glucose, insulin and C-peptide, the index of the homeostasis model assessment of insulin resistance (HOMA-IR) and islet β-cell secretion (HOMA-β) were calculated. We measured the hepatic mRNA expression levels of IRS2, phosphatidylinositol-3-kinases catalytic subunit alpha (PIK3CA), AKT by real-time PCR. The protein expression of total IRS2 (tIRS2), phosphorylated IRS2 at Ser731 (pSer731), total PIK3CA (tPIK3CA), total Akt (tAkt), phosphorylated Akt at Thr308 (pThr308) in liver were analyzed by western blot. We observed that compared to the non-exercise group, insulin and HOMA-IR index were significantly higher in the none-exercise toxic group (p < 0.05), while glucose, insulin, C-peptide and HOMA-IR index were significantly lower in the moderate-intensity exercise group (p < 0.05). In the high-intensity exercise group, the HOMA-IR index was significantly lower and the gene expression of IRS2 was significantly higher than in the non-exercise group (p < 0.05). Besides that, the HOMA-β index in the moderate-intensity exercise toxic group was significantly higher compared to the none-exercise toxic group and moderate-intensity exercise group (p < 0.05). The level of IRS2mRNA was significantly lower in the high-intensity exercise toxic group than in the high-intensity exercise group (p < 0.05). Our results demonstrated that 8-week TCDD exposure could induce insulin resistance in rats, while exercise could improve insulin sensitivity in which moderate intensity was more obvious than high intensity exercise. Meanwhile, both intensity exercise could not effectively alleviate the insulin resistance induced by TCDD, but high intensity exercise could promote compensatory insulin secretion to maintain glucose homeostasis. Although the gene expression of IRS2 was changed in high-intensity exercise groups, the mediation role of the hepatic IRS2/PI3K/AKT pathway in the effects of exercise and TCDD exposure on glucose metabolism remains very limited.
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Affiliation(s)
- Huohuo Wang
- School of Sports Medicine and Rehabilitation, Beijing Sport University, Beijing 100084, China; (H.W.); (J.W.); (Y.Z.)
| | - Juanjuan Wang
- School of Sports Medicine and Rehabilitation, Beijing Sport University, Beijing 100084, China; (H.W.); (J.W.); (Y.Z.)
| | - Yihua Zhu
- School of Sports Medicine and Rehabilitation, Beijing Sport University, Beijing 100084, China; (H.W.); (J.W.); (Y.Z.)
| | - Huiping Yan
- School of Sports Medicine and Rehabilitation, Beijing Sport University, Beijing 100084, China; (H.W.); (J.W.); (Y.Z.)
| | - Yifan Lu
- School of Sports Medicine and Rehabilitation, Beijing Sport University, Beijing 100084, China; (H.W.); (J.W.); (Y.Z.)
- Key Laboratory of Sports and Physical Fitness of the Ministry of Education, Beijing Sport University, Beijing 100084, China
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14
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Cunningham RP, Moore MP, Dashek RJ, Meers GM, Takahashi T, Sheldon RD, Wheeler AA, Diaz-Arias A, Ibdah JA, Parks EJ, Thyfault JP, Rector RS. Critical Role for Hepatocyte-Specific eNOS in NAFLD and NASH. Diabetes 2021; 70:2476-2491. [PMID: 34380696 PMCID: PMC8564406 DOI: 10.2337/db20-1228] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 07/30/2021] [Indexed: 11/13/2022]
Abstract
Regulation of endothelial nitric oxide synthase (eNOS) in hepatocytes may be an important target in nonalcoholic fatty liver disease (NAFLD) development and progression to nonalcoholic steatohepatitis (NASH). In this study, we show genetic deletion and viral knockdown of hepatocyte-specific eNOS exacerbated hepatic steatosis and inflammation, decreased hepatic mitochondrial fatty acid oxidation and respiration, increased mitochondrial H2O2 emission, and impaired the hepatic mitophagic (BNIP3 and LC3II) response. Conversely, overexpressing eNOS in hepatocytes in vitro and in vivo increased hepatocyte mitochondrial respiration and attenuated Western diet-induced NASH. Moreover, patients with elevated NAFLD activity score (histology score of worsening steatosis, hepatocyte ballooning, and inflammation) exhibited reduced hepatic eNOS expression, which correlated with reduced hepatic mitochondrial fatty acid oxidation and lower hepatic protein expression of mitophagy protein BNIP3. The current study reveals an important molecular role for hepatocyte-specific eNOS as a key regulator of NAFLD/NASH susceptibility and mitochondrial quality control with direct clinical correlation to patients with NASH.
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Affiliation(s)
- Rory P Cunningham
- Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO
| | - Mary P Moore
- Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO
| | - Ryan J Dashek
- Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
- Comparative Medicine Program, University of Missouri, Columbia, MO
| | - Grace M Meers
- Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO
| | - Takamune Takahashi
- Division of Nephrology and Hypertension, Vanderbilt University School of Medicine, Nashville, TN
| | - Ryan D Sheldon
- Metabolic and Nutritional Programming, Center for Cancer and Cell Biology, Van Andel Institute, Grand Rapids, MI
| | | | | | - Jamal A Ibdah
- Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Missouri, Columbia, MO
| | - Elizabeth J Parks
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Missouri, Columbia, MO
| | - John P Thyfault
- Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS
- Kansas City VA Medical Center, Kansas City, MO
| | - R Scott Rector
- Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Missouri, Columbia, MO
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15
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Li Y, Wu J, Yang M, Wei L, Wu H, Wang Q, Shi H. Physiological evidence of mitochondrial permeability transition pore opening caused by lipid deposition leading to hepatic steatosis in db/db mice. Free Radic Biol Med 2021; 162:523-532. [PMID: 33220425 DOI: 10.1016/j.freeradbiomed.2020.11.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 11/02/2020] [Accepted: 11/11/2020] [Indexed: 02/07/2023]
Abstract
Mitochondrial permeability transition pore (mPTP) is an important regulator in cell apoptosis and necrosis. However, its role in hepatic steatosis, especially its electrophysiological properties transformation remains elusive. Herein, using diabetes mice, we investigated the role of mPTP in hepatic steatosis triggered by diabetes and the mechanisms involved. We found that hepatic steatosis altered mitochondrial morphology, generating mega mitochondria, mitochondria swelling, calcein fluorescence quenching and mitochondrial membrane potential depolarization. At the same time, we confirmed an augmented mPTP opening with patch clamping in liver mitoplasts in db/db mice and a similar transformation with arachidonic acid (AA) simulating liquid deposition. We also found mPTP opening was significantly attenuated in wt mice after removing mitochondrial matrix, while that in db/db mice remained active. In addition, we observed that AA could directly activate mPTP in inside-out mode, independent of matrix calcium. In conclusion, we for the first time provided a physiological evidence of mPTP opening in lipid deposition, which could be directly induced by AA without Ca2+ and can be inhibited by cyclosporine A. As a result, it led to mitochondria morphology and function transformation. This might provide insights into potential therapeutic target for future treatment of mitochondrial liver disease.
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Affiliation(s)
- Yuan Li
- Institute of Molecular Medicine, Peking University, Beijing, China.
| | - Jing Wu
- Institute of Molecular Medicine, Peking University, Beijing, China
| | - Min Yang
- Institute of Molecular Medicine, Peking University, Beijing, China
| | - Lisi Wei
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Hongkun Wu
- Institute of Molecular Medicine, Peking University, Beijing, China
| | - Qinyi Wang
- Institute of Molecular Medicine, Peking University, Beijing, China
| | - Hui Shi
- Institute of Molecular Medicine, Peking University, Beijing, China
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16
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Lensu S, Pariyani R, Mäkinen E, Yang B, Saleem W, Munukka E, Lehti M, Driuchina A, Lindén J, Tiirola M, Lahti L, Pekkala S. Prebiotic Xylo-Oligosaccharides Ameliorate High-Fat-Diet-Induced Hepatic Steatosis in Rats. Nutrients 2020; 12:nu12113225. [PMID: 33105554 PMCID: PMC7690286 DOI: 10.3390/nu12113225] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 10/12/2020] [Accepted: 10/20/2020] [Indexed: 12/12/2022] Open
Abstract
Understanding the importance of the gut microbiota (GM) in non-alcoholic fatty liver disease (NAFLD) has raised the hope for therapeutic microbes. We have shown that high hepatic fat content associated with low abundance of Faecalibacterium prausnitzii in humans and, further, the administration of F. prausnitzii prevented NAFLD in mice. Here, we aimed at targeting F. prausnitzii by prebiotic xylo-oligosaccharides (XOS) to treat NAFLD. First, the effect of XOS on F. prausnitzii growth was assessed in vitro. Then, XOS was supplemented or not with high (HFD, 60% of energy from fat) or low (LFD) fat diet for 12 weeks in Wistar rats (n = 10/group). XOS increased F. prausnitzii growth, having only a minor impact on the GM composition. When supplemented with HFD, XOS ameliorated hepatic steatosis. The underlying mechanisms involved enhanced hepatic β-oxidation and mitochondrial respiration. Nuclear magnetic resonance (1H-NMR) analysis of cecal metabolites showed that, compared to the HFD, the LFD group had a healthier cecal short-chain fatty acid profile and on the HFD, XOS reduced cecal isovalerate and tyrosine, metabolites previously linked to NAFLD. Cecal branched-chain fatty acids associated positively and butyrate negatively with hepatic triglycerides. In conclusion, XOS supplementation can ameliorate NAFLD by improving hepatic oxidative metabolism and affecting GM.
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Affiliation(s)
- Sanna Lensu
- Faculty of Sport and Health Sciences, University of Jyväskylä, FI-40014 Jyväskylä, Finland; (S.L.); (E.M.); (M.L.); (A.D.)
| | - Raghunath Pariyani
- Food Chemistry and Food Development, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland; (R.P.); (B.Y.)
| | - Elina Mäkinen
- Faculty of Sport and Health Sciences, University of Jyväskylä, FI-40014 Jyväskylä, Finland; (S.L.); (E.M.); (M.L.); (A.D.)
| | - Baoru Yang
- Food Chemistry and Food Development, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland; (R.P.); (B.Y.)
| | - Wisam Saleem
- Department of Future Technologies, University of Turku, FI-20014 Turku, Finland; (W.S.); (L.L.)
| | - Eveliina Munukka
- Institute of Biomedicine, University of Turku, FI-20014 Turku, Finland;
- Department of Clinical Microbiology, Turku University Hospital, FI-20521 Turku, Finland
| | - Maarit Lehti
- Faculty of Sport and Health Sciences, University of Jyväskylä, FI-40014 Jyväskylä, Finland; (S.L.); (E.M.); (M.L.); (A.D.)
| | - Anastasiia Driuchina
- Faculty of Sport and Health Sciences, University of Jyväskylä, FI-40014 Jyväskylä, Finland; (S.L.); (E.M.); (M.L.); (A.D.)
| | - Jere Lindén
- Veterinary Pathology and Parasitology, University of Helsinki, FIN-00014 Helsinki, Finland;
| | - Marja Tiirola
- Department of Environmental and Biological Sciences, University of Jyväskylä, FI-40014 Jyväskylä, Finland;
| | - Leo Lahti
- Department of Future Technologies, University of Turku, FI-20014 Turku, Finland; (W.S.); (L.L.)
| | - Satu Pekkala
- Faculty of Sport and Health Sciences, University of Jyväskylä, FI-40014 Jyväskylä, Finland; (S.L.); (E.M.); (M.L.); (A.D.)
- Department of Clinical Microbiology, Turku University Hospital, FI-20521 Turku, Finland
- Correspondence: ; Tel.: +358-45-358-28-98
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17
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Wang YM, Huang TL, Meng C, Zhang J, Fang NY. SIRT1 deacetylates mitochondrial trifunctional enzyme α subunit to inhibit ubiquitylation and decrease insulin resistance. Cell Death Dis 2020; 11:821. [PMID: 33009367 PMCID: PMC7532168 DOI: 10.1038/s41419-020-03012-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 09/08/2020] [Accepted: 09/11/2020] [Indexed: 12/18/2022]
Abstract
Dysregulation of free acid metabolism is a major contributor to the development of insulin resistance and diabetes. Mitochondrial trifunctional enzyme subunit (MTPα) has a critical role in fatty acid β-oxidation. However, the association between MTPα and insulin resistance is not definitively known. Here, we aimed to determine how MTPα affects insulin resistance. We tested how MTPα affected glucose uptake in insulin-resistant 3T3-L1 adipocytes and white adipose tissue (WAT) of db/db diabetic mice. We also measured how acetylation and ubiquitylation modifications regulated MTPα activation and stability, using quantitative real-time polymerase chain reactions, immunoblotting, and immunoprecipitation. We found that MTPα overexpression promoted glucose uptake via Glut4 translocation to the plasma membrane in 3T3-L1 adipocytes. Moreover, MTPα upregulation decreased glycemia in db/db mice. Deacetylation increased MTPα protein stability and its ability to reduce insulin resistance. The activation of SIRT1, a major deacetylase, prevented MTPα degradation by decreasing its acetylation in adipocytes. Our study demonstrates a new role for MTPα in reducing insulin resistance. Acetylation and ubiquitylation modifications of MTPα were crucial to regulating its function in glucose metabolism.
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Affiliation(s)
- Yan-Mei Wang
- Department of Geriatrics, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, No. 160 Pujian Road, Pudong New Area, Shanghai, 200127, China
| | - Ting-Lei Huang
- Department of Oncology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, No. 160 Pujian Road, Pudong New Area, Shanghai, 200127, China
| | - Chao Meng
- Department of Geriatrics, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, No. 160 Pujian Road, Pudong New Area, Shanghai, 200127, China
| | - Jia Zhang
- Department of Geriatrics, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, No. 160 Pujian Road, Pudong New Area, Shanghai, 200127, China.
| | - Ning-Yuan Fang
- Department of Geriatrics, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, No. 160 Pujian Road, Pudong New Area, Shanghai, 200127, China.
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18
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Khare T, Khare S, Angdisen JJ, Zhang Q, Stuckel A, Mooney BP, Ridenhour SE, Gitan RS, Hammoud GM, Ibdah JA. Defects in long-chain 3-hydroxy acyl-CoA dehydrogenase lead to hepatocellular carcinoma: A novel etiology of hepatocellular carcinoma. Int J Cancer 2020; 147:1461-1473. [PMID: 32115688 DOI: 10.1002/ijc.32943] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Revised: 01/02/2020] [Accepted: 02/17/2020] [Indexed: 12/14/2022]
Abstract
The incidence of both nonalcoholic fatty liver disease (NAFLD) and hepatocellular carcinoma (HCC) have been increasing at an alarming rate. Little is known about NAFLD without cirrhosis as a risk for HCC. Here we report, for the first time, generation of a mouse model with a defect in long-chain 3-hydoxy acyl-CoA dehydrogenase (LCHAD). The LCHAD exon 15 deletion was embryonic lethal to the homozygous mice whereas heterozygous mice (HT) develop significant hepatic steatosis starting at young age (3 months old) and HCC at older age (>13 months old) without any evidence of fibrosis or cirrhosis. None of the wild-type (WT) mice developed steatosis and HCC (n = 39), whereas HT-LCHAD mice (n = 41) showed steatosis and ~20% (8/41) developed liver masses with histological features of HCC. Proteomic analysis of liver tissues from WT-mice and HT-mice with no signs of HCC was conducted. Proteins with significant changes in abundance were identified by mass spectrometry. Abundance of 24 proteins was significantly different (p < 0.01) between WT and HT-LCHAD mice. The proteins found to vary in abundance are associated with different cellular response processes ranging from intermediary metabolism of carbohydrate, protein and lipid to oxidative stress, signal transduction and the process of tumorigenesis. Protein expression pattern of the HT-LCHAD mouse liver indicates predisposition to HCC and suggests that impaired hepatic mitochondrial fatty acid oxidation plays an important role in the development and progression of HCC. To assess the implication of these studies in human disease, we demonstrated significant downregulation of HADHA transcripts in HCC patients.
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Affiliation(s)
- Tripti Khare
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Missouri, Columbia, MO, USA
| | - Sharad Khare
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Missouri, Columbia, MO, USA.,Harry S Truman Veterans' Hospital, Columbia, MO, USA
| | - Jerry J Angdisen
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Missouri, Columbia, MO, USA
| | - Qiong Zhang
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Missouri, Columbia, MO, USA
| | - Alexei Stuckel
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Missouri, Columbia, MO, USA
| | - Brian P Mooney
- Gehrke Proteomics center, University of Missouri, Columbia, MO, USA
| | - Suzanne E Ridenhour
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Missouri, Columbia, MO, USA
| | - Raad S Gitan
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Missouri, Columbia, MO, USA
| | - Ghassan M Hammoud
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Missouri, Columbia, MO, USA
| | - Jamal A Ibdah
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Missouri, Columbia, MO, USA.,Harry S Truman Veterans' Hospital, Columbia, MO, USA.,Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
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19
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Olaniyi KS, Olatunji LA. Oral ethinylestradiol–levonorgestrel normalizes fructose-induced hepatic lipid accumulation and glycogen depletion in female rats. Can J Physiol Pharmacol 2019; 97:1042-1052. [DOI: 10.1139/cjpp-2019-0037] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The present study investigated the effects of oral ethinylestradiol–levonorgestrel (EEL) on hepatic lipid and glycogen contents during high fructose (HF) intake, and determined whether pyruvate dehydrogenase kinase-4 (PDK-4) and glucose-6-phosphate dehydrogenase (G6PD) activity were involved in HF and (or) EEL-induced hepatic dysmetabolism. Female Wistar rats weighing 140–160 g were divided into groups. The control, EEL, HF, and EEL+HF groups received water (vehicle, p.o.), 1.0 μg ethinylestradiol plus 5.0 μg levonorgestrel (p.o.), fructose (10% w/v), and EEL plus HF, respectively, on a daily basis for 8 weeks. Results revealed that treatment with EEL or HF led to insulin resistance, hyperinsulinemia, increased hepatic uric acid production and triglyceride content, reduced glycogen content, and reduced production of plasma or hepatic glutathione- and G6PD-dependent antioxidants. HF but not EEL also increased fasting glucose and hepatic PDK-4. Nonetheless, these alterations were attenuated by EEL in HF-treated rats. Our results demonstrate that hepatic lipid accumulation and glycogen depletion induced by HF is accompanied by increased PDK-4 and defective G6PD activity. The findings also suggest that EEL would attenuate hepatic lipid accumulation and glycogen depletion by suppression of PDK-4 and enhancement of a G6PD-dependent antioxidant barrier.
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Affiliation(s)
- Kehinde Samuel Olaniyi
- HOPE Cardiometabolic Research Team & Department of Physiology, Faculty of Basic Medical Sciences, University of Ilorin, Ilorin, Nigeria
- Department of Physiology, College of Medicine and Health Sciences, Afe Babalola University, Ado-Ekiti, Nigeria
| | - Lawrence Aderemi Olatunji
- HOPE Cardiometabolic Research Team & Department of Physiology, Faculty of Basic Medical Sciences, University of Ilorin, Ilorin, Nigeria
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20
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Sheldon RD, Meers GM, Morris EM, Linden MA, Cunningham RP, Ibdah JA, Thyfault JP, Laughlin MH, Rector RS. eNOS deletion impairs mitochondrial quality control and exacerbates Western diet-induced NASH. Am J Physiol Endocrinol Metab 2019; 317:E605-E616. [PMID: 31361543 PMCID: PMC6842915 DOI: 10.1152/ajpendo.00096.2019] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Dysregulated mitochondrial quality control leads to mitochondrial functional impairments that are central to the development and progression of hepatic steatosis to nonalcoholic steatohepatitis (NASH). Here, we identify hepatocellular localized endothelial nitric oxide synthase (eNOS) as a novel master regulator of mitochondrial quality control. Mice lacking eNOS were more susceptible to Western diet-induced hepatic inflammation and fibrosis in conjunction with decreased markers of mitochondrial biogenesis and turnover. The hepatocyte-specific influence was verified via magnetic activated cell sorting purified primary hepatocytes and in vitro siRNA-induced knockdown of eNOS. Hepatic mitochondria from eNOS knockout mice revealed decreased markers of mitochondrial biogenesis (PPARγ coactivator-1α, mitochondrial transcription factor A) and autophagy/mitophagy [BCL-2-interacting protein-3 (BNIP3), 1A/1B light chain 3B (LC3)], suggesting decreased mitochondrial turnover rate. eNOS knockout in primary hepatocytes exhibited reduced fatty acid oxidation capacity and were unable to mount a normal BNIP3 response to a mitophagic challenge compared with wild-type mice. Finally, we demonstrate that eNOS is required in primary hepatocytes to induce activation of the stress-responsive transcription factor nuclear factor erythroid 2-related factor 2 (NRF2). Thus, our data demonstrate that eNOS is an important regulator of hepatic mitochondrial content and function and NASH susceptibility.
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Affiliation(s)
- Ryan D Sheldon
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, Missouri
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
| | - Grace M Meers
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, Missouri
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
| | - E Matthew Morris
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas
| | - Melissa A Linden
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, Missouri
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
| | - Rory P Cunningham
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, Missouri
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
| | - Jamal A Ibdah
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, Missouri
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Missouri, Columbia, Missouri
| | - John P Thyfault
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas
- Kansas City Veterans Affairs Medical Center, Kansas City, Missouri
| | - M Harold Laughlin
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri
| | - R Scott Rector
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, Missouri
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Missouri, Columbia, Missouri
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
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21
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Teng W, Li Y, Du M, Lei X, Xie S, Ren F. Sulforaphane Prevents Hepatic Insulin Resistance by Blocking Serine Palmitoyltransferase 3-Mediated Ceramide Biosynthesis. Nutrients 2019; 11:E1185. [PMID: 31137828 PMCID: PMC6566605 DOI: 10.3390/nu11051185] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 05/22/2019] [Accepted: 05/23/2019] [Indexed: 12/20/2022] Open
Abstract
Sulforaphane (SFA), a naturally active isothiocyanate compound from cruciferous vegetables used in clinical trials for cancer treatment, was found to possess potency to alleviate insulin resistance. But its underlying molecular mechanisms are still incompletely understood. In this study, we assessed whether SFA could improve insulin sensitivity and glucose homeostasis both in vitro and in vivo by regulating ceramide production. The effects of SFA on glucose metabolism and expression levels of key proteins in the hepatic insulin signaling pathway were evaluated in insulin-resistant human hepatic carcinoma HepG2 cells. The results showed that SFA dose-dependently increased glucose uptake and intracellular glycogen content by regulating the insulin receptor substrate 1 (IRS-1)/protein kinase B (Akt) signaling pathway in insulin-resistant HepG2 cells. SFA also reduced ceramide contents and downregulated transcription of ceramide-related genes. In addition, knockdown of serine palmitoyltransferase 3 (SPTLC3) in HepG2 cells prevented ceramide accumulation and alleviated insulin resistance. Moreover, SFA treatment improved glucose tolerance and insulin sensitivity, inhibited SPTLC3 expression and hepatic ceramide production and reduced hepatic triglyceride content in vivo. We conclude that SFA recovers glucose homeostasis and improves insulin sensitivity by blocking ceramide biosynthesis through modulating SPTLC3, indicating that SFA may be a potential candidate for prevention and amelioration of hepatic insulin resistance via a ceramide-dependent mechanism.
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Affiliation(s)
- Wendi Teng
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing 100083, China.
| | - Yuan Li
- Key Laboratory of Functional Dairy, Co-constructed by ministry of Education and Beijing Municipality, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing 100083, China.
| | - Min Du
- Department of Animal Sciences, Washington State University, Pullman, WA 99164, USA.
| | - Xingen Lei
- Department of Animal Science, Cornell University, Ithaca, NY 14853, USA.
| | - Siyu Xie
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing 100083, China.
| | - Fazheng Ren
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing 100083, China.
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22
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Townsend LK, Medak KD, Peppler WT, Meers GM, Rector RS, LeBlanc PJ, Wright DC. High-saturated-fat diet-induced obesity causes hepatic interleukin-6 resistance via endoplasmic reticulum stress. J Lipid Res 2019; 60:1236-1249. [PMID: 31085628 DOI: 10.1194/jlr.m092510] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Revised: 04/23/2019] [Indexed: 12/14/2022] Open
Abstract
The relationship between liver interleukin-6 (IL-6) resistance following high-fat diet (HFD)-induced obesity and glucose intolerance is unclear. The purpose of this study was to assess the temporal development of hepatic IL-6 resistance and the role of endoplasmic reticulum (ER) stress in this process. We hypothesized that HFD would rapidly induce hepatic IL-6 resistance through a mechanism involving ER stress. Male C57BL/6N mice consumed chow or a HFD (60%) derived from lard (saturated) or olive oil (monounsaturated) for 4 days or 7 weeks before being injected intraperitoneally with IL-6 (6 ng·kg-1). Glucose, insulin, and pyruvate tolerance tests were used as proxies for systemic glucose metabolism and hepatic glucose production, respectively. Primary mouse hepatocytes were incubated with palmitate (saturated) and oleate (unsaturated) overnight, then treated with 20 ng/ml IL-6. ER stress was induced via tunicamycin or prevented by sodium phenylbutyrate (PBA). Seven weeks of a saturated, but not monounsaturated, HFD reduced hepatic IL-6 signaling in conjunction with hepatic ER stress. Palmitate directly impaired IL-6 signaling in hepatocytes along with inducing ER stress. Pharmacologically induced ER stress caused hepatic IL-6 resistance, whereas PBA reversed HFD-induced IL-6 resistance. Chronic HFD-induced obesity is associated with hepatic IL-6 resistance due to saturated FA-induced ER stress.
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Affiliation(s)
- Logan K Townsend
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Kyle D Medak
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Willem T Peppler
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Grace M Meers
- Division of Gastroenterology and Hepatology, School of Medicine University of Missouri, Columbia, MO.,Research Service, Harry S Truman Memorial VA Hospital, Columbia, MO
| | - R Scott Rector
- Nutrition and Exercise Physiology University of Guelph, Guelph, ON, Canada.,Division of Gastroenterology and Hepatology, School of Medicine University of Missouri, Columbia, MO.,Research Service, Harry S Truman Memorial VA Hospital, Columbia, MO
| | - Paul J LeBlanc
- Department of Health Sciences Brock University, St. Catharines, ON, Canada
| | - David C Wright
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
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23
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Olaniyi KS, Olatunji LA. Preventive effects of l-glutamine on gestational fructose-induced cardiac hypertrophy: involvement of pyruvate dehydrogenase kinase-4. Appl Physiol Nutr Metab 2019; 44:1345-1354. [PMID: 31082323 DOI: 10.1139/apnm-2018-0754] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Gestational fructose exposure has detrimental health consequences on both the maternal and fetus or offspring in the early or later life, contributing to epidemic rise in cardiometabolic syndrome including cardiac events. l-Glutamine has been shown to mitigate cardiac metabolic stress. However, the effect of l-glutamine on cardiac hypertrophy induced by gestational fructose exposure is not known. We therefore hypothesized that l-glutamine would prevent gestational fructose-induced cardiac hypertrophy, possibly by suppression of pyruvate dehydrogenase kinase-4 (PDK-4). Pregnant Wistar rats were allotted into the control, l-glutamine, gestational fructose exposure, and gestational fructose exposure plus l-glutamine groups (6 rats in each group). The groups received distilled water (vehicle, per os), 1 g/kg body weight l-glutamine (per os), 10% fructose (w/v) and 10% fructose (w/v) plus 1 g/kg l-glutamine (per os), respectively, daily for 19 days. Data from this study showed that gestational fructose-enriched drink caused cardiac hypertrophy with correspondent body weight gain, glucose dysregulation, increased cardiac PDK-4, triglyceride, glycogen, lactate, and uric acid production. On the other hand, defective glutathione-dependent antioxidant barrier was also observed in pregnant rats taking fructose-enriched drink. However, the gestational fructose-induced cardiac hypertrophy and its correlates were attenuated by l-glutamine. The present results demonstrate that gestational fructose-enriched drink induces cardiac hypertrophy that is accompanied by increased PDK-4. The findings also suggest that the inhibitory effect of l-glutamine on PDK-4 prevents the development of cardiac hypertrophy, thereby implying that PDK-4 may be a potential novel therapeutic intervention for cardiac hypertrophy especially in pregnancy.
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Affiliation(s)
- Kehinde Samuel Olaniyi
- HOPE Cardiometabolic Research Team and Department of Physiology, College of Health Sciences, University of Ilorin, P.M.B. 1515, Ilorin, Nigeria.,Department of Physiology, College of Medicine and Health Sciences, Afe Babalola University, Ado-Ekiti, Nigeria
| | - Lawrence Aderemi Olatunji
- HOPE Cardiometabolic Research Team and Department of Physiology, College of Health Sciences, University of Ilorin, P.M.B. 1515, Ilorin, Nigeria
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24
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Morris EM, Meers GME, Ruegsegger GN, Wankhade UD, Robinson T, Koch LG, Britton SL, Rector RS, Shankar K, Thyfault JP. Intrinsic High Aerobic Capacity in Male Rats Protects Against Diet-Induced Insulin Resistance. Endocrinology 2019; 160:1179-1192. [PMID: 31144719 PMCID: PMC6482035 DOI: 10.1210/en.2019-00118] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 04/02/2019] [Indexed: 01/30/2023]
Abstract
Low aerobic capacity increases the risk for insulin resistance but the mechanisms are unknown. In this study, we tested susceptibility to acute (3-day) high-fat, high-sucrose diet (HFD)-induced insulin resistance in male rats selectively bred for divergent intrinsic aerobic capacity, that is, high-capacity running (HCR) and low-capacity running (LCR) rats. We employed hyperinsulinemic-euglycemic clamps, tracers, and transcriptome sequencing of skeletal muscle to test whether divergence in aerobic capacity impacted insulin resistance through systemic and tissue-specific metabolic adaptations. An HFD evoked decreased insulin sensitivity and insulin signaling in muscle and liver in LCR rats, whereas HCR rats were protected. An HFD led to increased glucose transport in skeletal muscle (twofold) of HCR rats while increasing glucose transport into adipose depots of the LCR rats (twofold). Skeletal muscle transcriptome revealed robust differences in the gene profile of HCR vs LCR on low-fat diet and HFD conditions, including robust differences in specific genes involved in lipid metabolism, adipogenesis, and differentiation. HCR transcriptional adaptations to an acute HFD were more robust than for LCR and included genes driving mitochondrial energy metabolism. In conclusion, intrinsic aerobic capacity robustly impacts systemic and skeletal muscle adaptations to HFD-induced alterations in insulin resistance, an effect that is likely driven by baseline differences in oxidative capacity, gene expression profile, and transcriptional adaptations to an HFD.
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Affiliation(s)
- E Matthew Morris
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas
- Research Service, Kansas City VA Medical Center, Kansas City, Missouri
| | - Grace M E Meers
- Department of Nutrition and Exercise Physiology, University of Missouri–Columbia, Columbia, Missouri
| | - Gregory N Ruegsegger
- Department of Biomedical Sciences, University of Missouri–Columbia, Columbia, Missouri
| | - Umesh D Wankhade
- Arkansas Children’s Nutrition Center, University of Arkansas for Medical Sciences, Little Rock, Arkansas
- Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Tommy Robinson
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas
| | - Lauren G Koch
- Department of Physiology and Pharmacology, University of Toledo, Toledo, Ohio
| | - Steven L Britton
- Deparment of Anesthesiology, University of Michigan, Ann Arbor, Michigan
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - R Scott Rector
- Department of Nutrition and Exercise Physiology, University of Missouri–Columbia, Columbia, Missouri
- Research Service, Harry S. Truman Memorial Veterans Hospital, Columbia, Missouri
| | - Kartik Shankar
- Arkansas Children’s Nutrition Center, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - John P Thyfault
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas
- Research Service, Kansas City VA Medical Center, Kansas City, Missouri
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25
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Inhibition of pyruvate dehydrogenase kinase-4 by l-glutamine protects pregnant rats against fructose-induced obesity and hepatic lipid accumulation. Biomed Pharmacother 2019; 110:59-67. [DOI: 10.1016/j.biopha.2018.11.038] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 10/29/2018] [Accepted: 11/10/2018] [Indexed: 12/13/2022] Open
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26
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Peppler WT, Townsend LK, Meers GM, Panasevich MR, MacPherson REK, Rector RS, Wright DC. Acute administration of IL-6 improves indices of hepatic glucose and insulin homeostasis in lean and obese mice. Am J Physiol Gastrointest Liver Physiol 2019; 316:G166-G178. [PMID: 30383412 DOI: 10.1152/ajpgi.00097.2018] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Obesity can lead to impairments in hepatic glucose and insulin homeostasis, and although exercise is an effective treatment, the molecular targets remain incompletely understood. As IL-6 is an exercise-inducible cytokine, we aimed to identify whether IL-6 itself influences hepatic glucose and insulin homeostasis and whether this response differs during obesity. In vivo, male mice were fed a low-fat diet (LFD; 10% kcal) or a high-fat diet (HFD; 60% kcal) for 7 wk, which induced obesity and hepatic lipid accumulation. LFD- and HFD-fed mice were injected with IL-6 (400 ng, 75 min) or PBS and then with insulin (1 U/kg; ~15 min) or saline, at which point livers were collected. In both LFD- and HFD-fed mice, IL-6 decreased blood glucose and mRNA expression of gluconeogenic genes alongside increased phosphorylation of AKT in comparison to PBS controls, and this occurred without changes in circulating insulin. To determine whether this effect of IL-6 was directly on the liver, we completed in vitro isolated primary hepatocyte experiments from chow-fed mice and cultured with or without exposure to free fatty acid (250 μm palmitate and 250 μm oleate, 24 h) to induce lipid accumulation. In both control and free fatty acid-treated hepatocytes, IL-6 (20 ng/ml, 75 min) slightly attenuated insulin-stimulated (10 nM; ~15 min) AKT phosphorylation. Together, these data suggest that IL-6 may lead to improvements in indices of hepatic glucose and insulin homeostasis in vivo; however, this is likely due to an indirect effect on the hepatocyte. NEW & NOTEWORTHY In this study, we used lean and obese mice and found that a single injection of IL-6 improved glucose tolerance, decreased hepatic gluconeogenic gene expression, and increased hepatic phosphorylation of AKT. In primary hepatocytes cultured under control and lipid-laden conditions, IL-6 had a mild, but deleterious, effect on phosphorylation of AKT. Our results show that the beneficial effects of IL-6 on glucose and insulin homeostasis, in vivo, are maintained in obesity.
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Affiliation(s)
- Willem T Peppler
- Department of Human Health and Nutritional Sciences, University of Guelph , Guelph, Ontario , Canada
| | - Logan K Townsend
- Department of Human Health and Nutritional Sciences, University of Guelph , Guelph, Ontario , Canada
| | - Grace M Meers
- Division of Gastroenterology and Hepatology, School of Medicine, University of Missouri , Columbia, Missouri.,Research Service, Harry S. Truman Memorial Veterans' Hospital , Columbia, Missouri
| | - Matthew R Panasevich
- Nutrition and Exercise Physiology, University of Missouri , Columbia, Missouri.,Research Service, Harry S. Truman Memorial Veterans' Hospital , Columbia, Missouri
| | | | - R Scott Rector
- Nutrition and Exercise Physiology, University of Missouri , Columbia, Missouri.,Division of Gastroenterology and Hepatology, School of Medicine, University of Missouri , Columbia, Missouri.,Research Service, Harry S. Truman Memorial Veterans' Hospital , Columbia, Missouri
| | - David C Wright
- Department of Human Health and Nutritional Sciences, University of Guelph , Guelph, Ontario , Canada
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27
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Ren L, Zhou X, Huang X, Wang C, Li Y. The IRS/PI3K/Akt signaling pathway mediates olanzapine-induced hepatic insulin resistance in male rats. Life Sci 2018; 217:229-236. [PMID: 30550886 DOI: 10.1016/j.lfs.2018.12.015] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Revised: 12/07/2018] [Accepted: 12/10/2018] [Indexed: 11/19/2022]
Abstract
AIMS Chronic treatment with antipsychotics, especially most of atypical ones, leads to development of metabolic abnormalities. Olanzapine is an atypical antipsychotic widely used in the treatment of schizophrenia and bipolar disorder. The mechanisms underlying olanzapine-induced metabolic adverse effects in the liver, however, remain unclear. This study was designed to investigate olanzapine-induced insulin-desensitivity in the liver. MAIN METHODS Male rats were treated with olanzapine (5 mg/kg, by a gavage method, once daily for consecutive 8 weeks. Blood and liver variables were determined enzymatically or histologically. Gene/protein expression was analyzed by real-time PCR and Western blot. KEY FINDINGS Olanzapine treatment significantly increased fasting plasma insulin concentration, the index of the homeostasis model assessment of insulin resistance (HOMA-IR), and hepatic triglyceride and fatty droplet accumulation in rats. Hepatic gene/protein expression profile revealed that olanzapine activated mRNA and protein expression of sterol regulatory element-binding protein-1c, and mRNA levels of its downstream lipogenic enzymes, acetyl-CoA carboxylase-1, fatty acid synthase and stearoyl-CoA desaturase-1. More importantly, phosphorylated protein level of both Ser307 in insulin receptor substrate (IRS)-1 and Ser731 in IRS-2 was increased. Furthermore, phosphorylation of Tyr607 in phosphoinositide 3-kinase (PI3K) p85α, Ser473 in Akt and Ser2448 in mammalian target of rapamycin was also enhanced. SIGNIFICANCE Our results suggest that the IRS/PI3K/Akt signaling pathway mediates olanzapine-induced hepatic insulin resistance in male rats. Our findings may provide better understanding of the antipsychotic-induced metabolic adverse effects.
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Affiliation(s)
- Liying Ren
- Department of Pharmacy, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Xia Zhou
- Department of Pharmacy, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Xiaoqian Huang
- Department of Pharmacy, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Chunxia Wang
- Department of Pharmacy, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China; Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China.
| | - Yuhao Li
- Department of Pharmacy, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China; Endocrinology and Metabolism Group, Sydney Institute of Health Sciences, Sydney Institute of Traditional Chinese Medicine, Sydney, NSW 2000, Australia.
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28
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Archer AE, Rogers RS, Von Schulze AT, Wheatley JL, Morris EM, McCoin CS, Thyfault JP, Geiger PC. Heat shock protein 72 regulates hepatic lipid accumulation. Am J Physiol Regul Integr Comp Physiol 2018; 315:R696-R707. [PMID: 29924632 PMCID: PMC6230886 DOI: 10.1152/ajpregu.00073.2018] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 06/14/2018] [Accepted: 06/14/2018] [Indexed: 12/29/2022]
Abstract
Induction of the chaperone heat shock protein 72 (HSP72) through heat treatment (HT), exercise, or overexpression improves glucose tolerance and mitochondrial function in skeletal muscle. Less is known about HSP72 function in the liver where lipid accumulation can result in insulin resistance and nonalcoholic fatty liver disease (NAFLD). The purpose of this study was 1) to determine whether weekly in vivo HT induces hepatic HSP72 and improves glucose tolerance in rats fed a high-fat diet (HFD) and 2) to determine the ability of HSP72 to protect against lipid accumulation and mitochondrial dysfunction in primary hepatocytes. Male Wistar rats were fed an HFD for 15 wk and were given weekly HT (41°C, 20 min) or sham treatments (37°C, 20 min) for the final 7 wk. Glucose tolerance and insulin sensitivity were assessed, along with HSP72 induction and triglyceride storage, in the skeletal muscle and liver. The effect of an acute loss of HSP72 in primary hepatocytes was examined via siRNA. Weekly in vivo HT improved glucose tolerance, elevated muscle and hepatic HSP72 protein content, and reduced muscle triglyceride storage. In primary hepatocytes, mitochondrial morphology was changed, and fatty acid oxidation was reduced in small interfering HSP72 (siHSP72)-treated hepatocytes. Lipid accumulation following palmitate treatment was increased in siHSP72-treated hepatocytes. These data suggest that HT may improve systemic metabolism via induction of hepatic HSP72. Additionally, acute loss of HSP72 in primary hepatocytes impacts mitochondrial health as well as fat oxidation and storage. These findings suggest therapies targeting HSP72 in the liver may prevent NAFLD.
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Affiliation(s)
- Ashley E Archer
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center , Kansas City, Kansas
| | - Robert S Rogers
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center , Kansas City, Kansas
| | - Alex T Von Schulze
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center , Kansas City, Kansas
| | - Joshua L Wheatley
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center , Kansas City, Kansas
| | - E Matthew Morris
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center , Kansas City, Kansas
- Research Service, Kansas City Veterans Affairs Medical Center , Kansas City, Missouri
| | - Colin S McCoin
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center , Kansas City, Kansas
- Research Service, Kansas City Veterans Affairs Medical Center , Kansas City, Missouri
| | - John P Thyfault
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center , Kansas City, Kansas
- Research Service, Kansas City Veterans Affairs Medical Center , Kansas City, Missouri
| | - Paige C Geiger
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center , Kansas City, Kansas
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Ipsen DH, Lykkesfeldt J, Tveden-Nyborg P. Molecular mechanisms of hepatic lipid accumulation in non-alcoholic fatty liver disease. Cell Mol Life Sci 2018; 75:3313-3327. [PMID: 29936596 PMCID: PMC6105174 DOI: 10.1007/s00018-018-2860-6] [Citation(s) in RCA: 756] [Impact Index Per Article: 126.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 06/18/2018] [Accepted: 06/20/2018] [Indexed: 12/17/2022]
Abstract
Non-alcoholic fatty liver disease (NAFLD) is currently the world's most common liver disease, estimated to affect up to one-fourth of the population. Hallmarked by hepatic steatosis, NAFLD is associated with a multitude of detrimental effects and increased mortality. This narrative review investigates the molecular mechanisms of hepatic steatosis in NAFLD, focusing on the four major pathways contributing to lipid homeostasis in the liver. Hepatic steatosis is a consequence of lipid acquisition exceeding lipid disposal, i.e., the uptake of fatty acids and de novo lipogenesis surpassing fatty acid oxidation and export. In NAFLD, hepatic uptake and de novo lipogenesis are increased, while a compensatory enhancement of fatty acid oxidation is insufficient in normalizing lipid levels and may even promote cellular damage and disease progression by inducing oxidative stress, especially with compromised mitochondrial function and increased oxidation in peroxisomes and cytochromes. While lipid export initially increases, it plateaus and may even decrease with disease progression, sustaining the accumulation of lipids. Fueled by lipo-apoptosis, hepatic steatosis leads to systemic metabolic disarray that adversely affects multiple organs, placing abnormal lipid metabolism associated with NAFLD in close relation to many of the current life-style-related diseases.
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Affiliation(s)
- David Højland Ipsen
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Ridebanevej 9, 1870, Frederiksberg C, Denmark
| | - Jens Lykkesfeldt
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Ridebanevej 9, 1870, Frederiksberg C, Denmark
| | - Pernille Tveden-Nyborg
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Ridebanevej 9, 1870, Frederiksberg C, Denmark.
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30
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Zhao M, Yuan MM, Yuan L, Huang LL, Liao JH, Yu XL, Su C, Chen YH, Yang YY, Yu H, Xu DX. Chronic folate deficiency induces glucose and lipid metabolism disorders and subsequent cognitive dysfunction in mice. PLoS One 2018; 13:e0202910. [PMID: 30153273 PMCID: PMC6112663 DOI: 10.1371/journal.pone.0202910] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 08/10/2018] [Indexed: 12/11/2022] Open
Abstract
Previous studies have shown that folate levels were decreased in patients with type 2 diabetes (T2D) and further lowered in T2D patients with cognitive impairment. However, whether folate deficiency could cause T2D and subsequent cognitive dysfunction is still unknown. The present study aimed to explore the effects of chronic folate deficiency (CFD) on glucose and lipid metabolism and cognitive function in mice. Seven-week-old mice were fed with either a CFD or control diet for 25 weeks. Serum folate was significantly reduced, whereas serum total homocysteine was significantly increased in the CFD group. Moreover, CFD induced obesity after a 6-week diet treatment, glucose intolerance and insulin resistance after a 16-week-diet treatment. In addition, CFD reduced the hepatic p-Akt/Akt ratio in response to acute insulin administration. Moreover, CFD increased serum triglyceride levels, upregulated hepatic Acc1 and Fasn mRNA expression, and downregulated hepatic Cd36 and ApoB mRNA expression. After a 24-week diet treatment, CFD induced anxiety-related activities and impairment of spatial learning and memory performance. This study demonstrates that folate deficiency could induce obesity, glucose and lipid metabolism disorders and subsequent cognitive dysfunction.
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Affiliation(s)
- Mei Zhao
- School of Nursing, Anhui Medical University, Hefei, China
- Anhui Provincial Key Laboratory of Population Health & Aristogenics, Hefei, China
| | - Man Man Yuan
- School of Nursing, Anhui Medical University, Hefei, China
| | - Li Yuan
- School of Nursing, Anhui Medical University, Hefei, China
| | - Li Li Huang
- School of Nursing, Anhui Medical University, Hefei, China
| | - Jian Hong Liao
- School of Nursing, Anhui Medical University, Hefei, China
| | - Xiao Ling Yu
- School of Nursing, Anhui Medical University, Hefei, China
| | - Chang Su
- School of Nursing, Anhui Medical University, Hefei, China
| | - Yuan Hua Chen
- Anhui Provincial Key Laboratory of Population Health & Aristogenics, Hefei, China
- Department of Histology and Embryology, Anhui Medical University, Hefei, China
| | - Yu Ying Yang
- School of Nursing, Anhui Medical University, Hefei, China
| | - Huan Yu
- School of Nursing, Anhui Medical University, Hefei, China
| | - De Xiang Xu
- Anhui Provincial Key Laboratory of Population Health & Aristogenics, Hefei, China
- Department of Toxicology, Anhui Medical University, Hefei, China
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31
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Capybara Oil Improves Hepatic Mitochondrial Dysfunction, Steatosis, and Inflammation in a Murine Model of Nonalcoholic Fatty Liver Disease. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2018; 2018:4956079. [PMID: 29853957 PMCID: PMC5949171 DOI: 10.1155/2018/4956079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/09/2018] [Accepted: 03/21/2018] [Indexed: 12/12/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is recognized as the most common cause of liver dysfunction worldwide and is commonly associated with obesity. Evidences suggest that NAFLD might be a mitochondrial disease, which contributes to the hepatic steatosis, oxidative stress, cytokine release, and cell death. Capybara oil (CO) is a rich source of polyunsaturated fatty acids (PUFA), which is known to improve inflammation and oxidative stress. In order to determine the effects of CO on NAFLD, C57Bl/6 mice were divided into 3 groups and fed a high-fat diet (HFD) (NAFLD group and NAFLD + CO group) or a control diet (CG group) during 16 weeks. The CO (1.5 g/kg/daily) was administered by gavage during the last 4 weeks of the diet protocol. We evaluated plasma liver enzymes, hepatic steatosis, and cytokine expression in liver as well as hepatocyte ultrastructural morphology and mitochondrial function. CO treatment suppressed hepatic steatosis, attenuated inflammatory response, and decreased plasma alanine aminotransferase (ALT) in mice with NAFLD. CO was also capable of restoring mitochondrial ultrastructure and function as well as balance superoxide dismutase and catalase levels. Our findings indicate that CO treatment has positive effects on NAFLD improving mitochondrial dysfunction, steatosis, acute inflammation, and oxidative stress.
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Nassir F, Arndt JJ, Johnson SA, Ibdah JA. Regulation of mitochondrial trifunctional protein modulates nonalcoholic fatty liver disease in mice. J Lipid Res 2018; 59:967-973. [PMID: 29581157 PMCID: PMC5983392 DOI: 10.1194/jlr.m080952] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 03/21/2018] [Indexed: 12/15/2022] Open
Abstract
Mitochondrial trifunctional protein (MTP) plays a critical role in the oxidation of long-chain fatty acids. We previously reported that aging mice (>9 months old) heterozygous for an MTP defect (MTP+/-) develop nonalcoholic fatty liver disease (NAFLD). We tested whether a high-fat diet (HFD) accelerates NAFLD in young MTP+/-mice, and whether overexpression of the nicotinamide adenine dinucleotide (NAD+)-dependent deacetylase sirtuin 3 (SIRT3) deacetylates MTP and improves mitochondrial function and NAFLD. Three-month-old WT and MTP+/- mice were fed HFD (60% cal fat) for 16 weeks and livers were assessed for fatty acid oxidation (FAO) and NAFLD. Compared with WT, MTP+/- mice displayed reduced hepatic SIRT3 levels and reduced FAO, with increased hepatic steatosis and the inflammatory marker CD68. Hepatic overexpression of SIRT3 in HFD-fed MTP+/- mice increased hepatic MTP protein levels at the posttranscriptional level. Immunoprecipitation of MTP from liver mitochondria followed by Western blot with acetyl-lysine antibody showed higher acetylation of MTP in MTP+/- compared with WT mice. Overexpression of SIRT3 in MTP+/- mice significantly reduced the acetylation of MTP compared with β-galactosidase controls, increased mitochondrial FAO, and reduced hepatic steatosis, CD68, and serum ALT levels. Taken together, our data indicate that deacetylation of MTP by SIRT3 improves mitochondrial function and rescues NAFLD in MTP+/- mice.
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Affiliation(s)
- Fatiha Nassir
- Departments of Medicine-Division of Gastroenterology and Hepatology, University of Missouri, Columbia, MO; Nutrition and Exercise Physiology, University of Missouri, Columbia, MO; United States Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
| | - Justin J Arndt
- Departments of Medicine-Division of Gastroenterology and Hepatology, University of Missouri, Columbia, MO
| | - Sarah A Johnson
- Departments of Medicine-Division of Gastroenterology and Hepatology, University of Missouri, Columbia, MO; United States Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
| | - Jamal A Ibdah
- Departments of Medicine-Division of Gastroenterology and Hepatology, University of Missouri, Columbia, MO; Nutrition and Exercise Physiology, University of Missouri, Columbia, MO; Medical Pharmacology & Physiology, University of Missouri, Columbia, MO; United States Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO.
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33
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Candeias E, Sebastião I, Cardoso S, Carvalho C, Santos MS, Oliveira CR, Moreira PI, Duarte AI. Brain GLP-1/IGF-1 Signaling and Autophagy Mediate Exendin-4 Protection Against Apoptosis in Type 2 Diabetic Rats. Mol Neurobiol 2018; 55:4030-4050. [PMID: 28573460 DOI: 10.1007/s12035-017-0622-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 05/16/2017] [Indexed: 02/08/2023]
Abstract
Type 2 diabetes (T2D) is a modern socioeconomic burden, mostly due to its long-term complications affecting nearly all tissues. One of them is the brain, whose dysfunctional intracellular quality control mechanisms (namely autophagy) may upregulate apoptosis, leading to cognitive dysfunction and Alzheimer disease (AD). Since impaired brain insulin signaling may constitute the crosslink between T2D and AD, its restoration may be potentially therapeutic herein. Accordingly, the insulinotropic anti-T2D drugs from glucagon-like peptide-1 (GLP-1) mimetics, namely, exendin-4 (Ex-4), could be a promising therapy. In line with this, we hypothesized that peripherally administered Ex-4 rescues brain intracellular signaling pathways, promoting autophagy and ultimately protecting against chronic T2D-induced apoptosis. Thus, we aimed to explore the effects of chronic, continuous, subcutaneous (s.c.) exposure to Ex-4 in brain cortical GLP-1/insulin/insulin-like growth factor-1 (IGF-1) signaling, and in autophagic and cell death mechanisms in middle-aged (8 months old), male T2D Goto-Kakizaki (GK) rats. We used brain cortical homogenates obtained from middle-aged (8 months old) male Wistar (control) and T2D GK rats. Ex-4 was continuously administered for 28 days, via s.c. implanted micro-osmotic pumps (5 μg/kg/day; infusion rate 2.5 μL/h). Peripheral characterization of the animal models was given by the standard biochemical analyses of blood or plasma, the intraperitoneal glucose tolerance test, and the heart rate. GLP-1, insulin, and IGF-1, their downstream signaling and autophagic markers were evaluated by specific ELISA kits and Western blotting. Caspase-like activities and other apoptotic markers were given by colorimetric methods and Western blotting. Chronic Ex-4 treatment attenuated peripheral features of T2D in GK rats, including hyperglycemia and insulin resistance. Furthermore, s.c. Ex-4 enhanced their brain cortical GLP-1 and IGF-1 levels, and subsequent signaling pathways. Specifically, Ex-4 stimulated protein kinase A (PKA) and phosphoinositide 3-kinase (PI3K)/Akt signaling, increasing cGMP and AMPK levels, and decreasing GSK3β and JNK activation in T2D rat brains. Moreover, Ex-4 regulated several markers for autophagy in GK rat brains (as mTOR, PI3K class III, LC3 II, Atg7, p62, LAMP-1, and Parkin), ultimately protecting against apoptosis (by decreasing several caspase-like activities and mitochondrial cytochrome c, and increasing Bcl2 levels upon T2D). Altogether, this study demonstrates that peripheral Ex-4 administration may constitute a promising therapy against the chronic complications of T2D affecting the brain.
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Affiliation(s)
- Emanuel Candeias
- CNC-Center for Neuroscience and Cell Biology, Rua Larga, Faculty of Medicine (Pólo 1, 1st Floor), University of Coimbra, 3004-517, Coimbra, Portugal
- Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Casa Costa Alemão - Pólo II, Rua D. Francisco de Lemos, 3030-789, Coimbra, Portugal
| | - Inês Sebastião
- CNC-Center for Neuroscience and Cell Biology, Rua Larga, Faculty of Medicine (Pólo 1, 1st Floor), University of Coimbra, 3004-517, Coimbra, Portugal
| | - Susana Cardoso
- CNC-Center for Neuroscience and Cell Biology, Rua Larga, Faculty of Medicine (Pólo 1, 1st Floor), University of Coimbra, 3004-517, Coimbra, Portugal
- Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Casa Costa Alemão - Pólo II, Rua D. Francisco de Lemos, 3030-789, Coimbra, Portugal
| | - Cristina Carvalho
- CNC-Center for Neuroscience and Cell Biology, Rua Larga, Faculty of Medicine (Pólo 1, 1st Floor), University of Coimbra, 3004-517, Coimbra, Portugal
- Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Casa Costa Alemão - Pólo II, Rua D. Francisco de Lemos, 3030-789, Coimbra, Portugal
| | - Maria Sancha Santos
- CNC-Center for Neuroscience and Cell Biology, Rua Larga, Faculty of Medicine (Pólo 1, 1st Floor), University of Coimbra, 3004-517, Coimbra, Portugal
- Life Sciences Department, University of Coimbra, Largo Marquês de Pombal, 3004-517, Coimbra, Portugal
| | - Catarina Resende Oliveira
- CNC-Center for Neuroscience and Cell Biology, Rua Larga, Faculty of Medicine (Pólo 1, 1st Floor), University of Coimbra, 3004-517, Coimbra, Portugal
- Institute of Biochemistry, Faculty of Medicine, University of Coimbra, 3004-504, Coimbra, Portugal
| | - Paula I Moreira
- CNC-Center for Neuroscience and Cell Biology, Rua Larga, Faculty of Medicine (Pólo 1, 1st Floor), University of Coimbra, 3004-517, Coimbra, Portugal.
- Institute of Physiology, Faculty of Medicine, University of Coimbra, 3004-504, Coimbra, Portugal.
| | - Ana I Duarte
- CNC-Center for Neuroscience and Cell Biology, Rua Larga, Faculty of Medicine (Pólo 1, 1st Floor), University of Coimbra, 3004-517, Coimbra, Portugal.
- Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Casa Costa Alemão - Pólo II, Rua D. Francisco de Lemos, 3030-789, Coimbra, Portugal.
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Natarajan SK, Ibdah JA. Role of 3-Hydroxy Fatty Acid-Induced Hepatic Lipotoxicity in Acute Fatty Liver of Pregnancy. Int J Mol Sci 2018; 19:ijms19010322. [PMID: 29361796 PMCID: PMC5796265 DOI: 10.3390/ijms19010322] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Revised: 01/16/2018] [Accepted: 01/16/2018] [Indexed: 12/16/2022] Open
Abstract
Acute fatty liver of pregnancy (AFLP), a catastrophic illness for both the mother and the unborn offspring, develops in the last trimester of pregnancy with significant maternal and perinatal mortality. AFLP is also recognized as an obstetric and medical emergency. Maternal AFLP is highly associated with a fetal homozygous mutation (1528G>C) in the gene that encodes for mitochondrial long-chain hydroxy acyl-CoA dehydrogenase (LCHAD). The mutation in LCHAD results in the accumulation of 3-hydroxy fatty acids, such as 3-hydroxy myristic acid, 3-hydroxy palmitic acid and 3-hydroxy dicarboxylic acid in the placenta, which are then shunted to the maternal circulation leading to the development of acute liver injury observed in patients with AFLP. In this review, we will discuss the mechanistic role of increased 3-hydroxy fatty acid in causing lipotoxicity to the liver and in inducing oxidative stress, mitochondrial dysfunction and hepatocyte lipoapoptosis. Further, we also review the role of 3-hydroxy fatty acids in causing placental damage, pancreatic islet β-cell glucolipotoxicity, brain damage, and retinal epithelial cells lipoapoptosis in patients with LCHAD deficiency.
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Affiliation(s)
- Sathish Kumar Natarajan
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583-0806, USA.
| | - Jamal A Ibdah
- Division of Gastroenterology and Hepatology, University of Missouri, Columbia, MO 65212, USA.
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO 65212, USA.
- Harry S. Truman Memorial Veterans Medical Center, Columbia, MO 65201, USA.
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Goetzman ES, Gong Z, Schiff M, Wang Y, Muzumdar RH. Metabolic pathways at the crossroads of diabetes and inborn errors. J Inherit Metab Dis 2018; 41:5-17. [PMID: 28952033 PMCID: PMC6757345 DOI: 10.1007/s10545-017-0091-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 08/30/2017] [Accepted: 09/08/2017] [Indexed: 12/18/2022]
Abstract
Research over the past two decades has led to advances in our understanding of the genetic and metabolic factors that underlie the pathogenesis of type 2 diabetes mellitus (T2DM). While T2DM is defined by its hallmark metabolic symptoms, the genetic risk factors for T2DM are more immune-related than metabolism-related, and the observed metabolic disease may be secondary to chronic inflammation. Regardless, these metabolic changes are not benign, as the accumulation of some metabolic intermediates serves to further drive the inflammation and cell stress, eventually leading to insulin resistance and ultimately to T2DM. Because many of the biochemical changes observed in the pre-diabetic state (i.e., ectopic lipid storage, increased acylcarnitines, increased branched-chain amino acids) are also observed in patients with rare inborn errors of fatty acid and amino acid metabolism, an interesting question is raised regarding whether isolated metabolic gene defects can confer an increased risk for T2DM. In this review, we attempt to address this question by summarizing the literature regarding the metabolic pathways at the crossroads of diabetes and inborn errors of metabolism. Studies using cell culture and animal models have revealed that, within a given pathway, disrupting some genes can lead to insulin resistance while for others there may be no effect or even improved insulin sensitivity. This differential response to ablating a single metabolic gene appears to be dependent upon the specific metabolic intermediates that accumulate and whether these intermediates subsequently activate inflammatory pathways. This highlights the need for future studies to determine whether certain inborn errors may confer increased risk for diabetes as the patients age.
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Affiliation(s)
- Eric S Goetzman
- Department of Pediatrics, School of Medicine, University of Pittsburgh, 4401 Penn Ave, Pittsburgh, PA, 15224, USA.
- Children's Hospital of Pittsburgh, Rangos 5117, 4401 Penn Avenue, Pittsburgh, PA, 15224, USA.
| | - Zhenwei Gong
- Department of Pediatrics, School of Medicine, University of Pittsburgh, 4401 Penn Ave, Pittsburgh, PA, 15224, USA
| | - Manuel Schiff
- UMR1141, PROTECT, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
- Reference Center for Inborn Errors of Metabolism, Robert Debré University Hospital, APHP, Paris, France
| | - Yan Wang
- Department of Pediatrics, School of Medicine, University of Pittsburgh, 4401 Penn Ave, Pittsburgh, PA, 15224, USA
| | - Radhika H Muzumdar
- Department of Pediatrics, School of Medicine, University of Pittsburgh, 4401 Penn Ave, Pittsburgh, PA, 15224, USA
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36
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Geisler CE, Renquist BJ. Hepatic lipid accumulation: cause and consequence of dysregulated glucoregulatory hormones. J Endocrinol 2017; 234:R1-R21. [PMID: 28428362 DOI: 10.1530/joe-16-0513] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 04/20/2017] [Indexed: 12/11/2022]
Abstract
Fatty liver can be diet, endocrine, drug, virus or genetically induced. Independent of cause, hepatic lipid accumulation promotes systemic metabolic dysfunction. By acting as peroxisome proliferator-activated receptor (PPAR) ligands, hepatic non-esterified fatty acids upregulate expression of gluconeogenic, beta-oxidative, lipogenic and ketogenic genes, promoting hyperglycemia, hyperlipidemia and ketosis. The typical hormonal environment in fatty liver disease consists of hyperinsulinemia, hyperglucagonemia, hypercortisolemia, growth hormone deficiency and elevated sympathetic tone. These endocrine and metabolic changes further encourage hepatic steatosis by regulating adipose tissue lipolysis, liver lipid uptake, de novo lipogenesis (DNL), beta-oxidation, ketogenesis and lipid export. Hepatic lipid accumulation may be induced by 4 separate mechanisms: (1) increased hepatic uptake of circulating fatty acids, (2) increased hepatic de novo fatty acid synthesis, (3) decreased hepatic beta-oxidation and (4) decreased hepatic lipid export. This review will discuss the hormonal regulation of each mechanism comparing multiple physiological models of hepatic lipid accumulation. Nonalcoholic fatty liver disease (NAFLD) is typified by increased hepatic lipid uptake, synthesis, oxidation and export. Chronic hepatic lipid signaling through PPARgamma results in gene expression changes that allow concurrent activity of DNL and beta-oxidation. The importance of hepatic steatosis in driving systemic metabolic dysfunction is highlighted by the common endocrine and metabolic disturbances across many conditions that result in fatty liver. Understanding the mechanisms underlying the metabolic dysfunction that develops as a consequence of hepatic lipid accumulation is critical to identifying points of intervention in this increasingly prevalent disease state.
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Affiliation(s)
- Caroline E Geisler
- School of Animal and Comparative Biomedical SciencesUniversity of Arizona, Tucson, Arizona, USA
| | - Benjamin J Renquist
- School of Animal and Comparative Biomedical SciencesUniversity of Arizona, Tucson, Arizona, USA
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Liu HX, Wang YM, Hu JP, Huang LY, Fang NY. Adipocyte differentiation is regulated by mitochondrial trifunctional protein α-subunit via sirtuin 1. Exp Cell Res 2017; 357:271-281. [PMID: 28552586 DOI: 10.1016/j.yexcr.2017.05.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 05/19/2017] [Accepted: 05/23/2017] [Indexed: 12/18/2022]
Abstract
Mitochondrial trifunctional protein α-subunit (MTPα) is involved in the fatty acid β-oxidation (FAO) pathway. Two MTPα activities, 3-hydroxyacyl-CoA dehydrogenase and long-chain hydratase, have been linked with the occurrence and development of obesity and obesity-related disorders. These activities catalyze two steps in the FAO pathway (the second and third reactions). However, the role of MTPα in the pathogenesis of obesity has not been evaluated, and the functional role of MTPα in adipocyte differentiation has not been determined. Here, we analyzed the functional role of MTPα using in vitro and in vivo models of adipogenesis. MTPα expression was upregulated during the differentiation of 3T3-L1 preadipocyte cells into adipocytes. MTPα gene silencing stimulated peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT-enhancer-binding protein alpha(C/EBPα) expression, which promoted adipocyte differentiation. By contrast, MTPα overexpression blocked adipogenesis in 3T3-L1 cells. Further analysis showed that MTPα positively regulated sirtuin 1 (SIRT1). Injection of preadipocytes overexpressing MTPα into athymic mice significantly impaired de novo fat pad formation compared with that of the control, and furthermore MTPα knockdown enhances fat pad formation at a time point earlier than 5-week, such as week-2 and week-3, when the control fat pad is not fully developed. In summary, our data indicate that MTPα is a novel factor that negatively regulates adipocyte differentiation. We propose a pathway in which MTPα inhibits adipogenesis by promoting SIRT1 expression, which represses PPARγ and attenuates adipogenesis.
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Affiliation(s)
- Hong-Xia Liu
- Department of Geriatrics, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, No. 160 Pujian Road, Pudong New Area, Shanghai 200127, China
| | - Yan-Mei Wang
- Department of Geriatrics, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, No. 160 Pujian Road, Pudong New Area, Shanghai 200127, China
| | - Jian-Ping Hu
- Department of Geriatrics, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, No. 160 Pujian Road, Pudong New Area, Shanghai 200127, China
| | - Li-Ying Huang
- Department of Geriatrics, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, No. 160 Pujian Road, Pudong New Area, Shanghai 200127, China
| | - Ning-Yuan Fang
- Department of Geriatrics, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, No. 160 Pujian Road, Pudong New Area, Shanghai 200127, China.
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38
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Sangüesa G, Baena M, Hutter N, Montañés JC, Sánchez RM, Roglans N, Laguna JC, Alegret M. The Addition of Liquid Fructose to a Western-Type Diet in LDL-R -/- Mice Induces Liver Inflammation and Fibrogenesis Markers without Disrupting Insulin Receptor Signalling after an Insulin Challenge. Nutrients 2017; 9:nu9030278. [PMID: 28294959 PMCID: PMC5372941 DOI: 10.3390/nu9030278] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 03/03/2017] [Accepted: 03/09/2017] [Indexed: 01/17/2023] Open
Abstract
A high consumption of fat and simple sugars, especially fructose, has been related to the development of insulin resistance, but the mechanisms involved in the effects of these nutrients are not fully understood. This study investigates the effects of a Western-type diet and liquid fructose supplementation, alone and combined, on insulin signalling and inflammation in low-density lipoprotein (LDL) receptor-deficient mice (LDL-R−/−). LDL-R−/− mice were fed chow or Western diet ±15% fructose solution for 12 weeks. Plasma glucose and insulin, and the expression of genes related to inflammation in the liver and visceral white adipose tissue (vWAT), were analysed. V-akt murine thymoma viral oncogene homolog-2 (Akt) activation was measured in the liver of the mice after a single injection of saline or insulin. None of the dietary interventions caused inflammation in vWAT, whereas the Western diet induced hepatic inflammation, which was further enhanced by liquid fructose, leading also to a significant increase in fibrogenesis markers. However, there was no change in plasma glucose or insulin, or insulin-induced Akt phosphorylation. In conclusion, hepatic inflammation and fibrogenesis markers induced by a Western diet supplemented with liquid fructose in LDL-R−/− mice are not associated with a significant impairment of hepatic insulin signalling.
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Affiliation(s)
- Gemma Sangüesa
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, School of Pharmacy and Food Sciences, University of Barcelona, 08028 Barcelona, Spain.
- Institute of Biomedicine, University of Barcelona, 08028 Barcelona, Spain.
| | - Miguel Baena
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, School of Pharmacy and Food Sciences, University of Barcelona, 08028 Barcelona, Spain.
- Institute of Biomedicine, University of Barcelona, 08028 Barcelona, Spain.
| | - Natalia Hutter
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, School of Pharmacy and Food Sciences, University of Barcelona, 08028 Barcelona, Spain.
| | - José Carlos Montañés
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, School of Pharmacy and Food Sciences, University of Barcelona, 08028 Barcelona, Spain.
| | - Rosa María Sánchez
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, School of Pharmacy and Food Sciences, University of Barcelona, 08028 Barcelona, Spain.
- Institute of Biomedicine, University of Barcelona, 08028 Barcelona, Spain.
- CIBER Fisiología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), Spain.
| | - Núria Roglans
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, School of Pharmacy and Food Sciences, University of Barcelona, 08028 Barcelona, Spain.
- Institute of Biomedicine, University of Barcelona, 08028 Barcelona, Spain.
- CIBER Fisiología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), Spain.
| | - Juan Carlos Laguna
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, School of Pharmacy and Food Sciences, University of Barcelona, 08028 Barcelona, Spain.
- Institute of Biomedicine, University of Barcelona, 08028 Barcelona, Spain.
- CIBER Fisiología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), Spain.
| | - Marta Alegret
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, School of Pharmacy and Food Sciences, University of Barcelona, 08028 Barcelona, Spain.
- Institute of Biomedicine, University of Barcelona, 08028 Barcelona, Spain.
- CIBER Fisiología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), Spain.
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Acetylation of Mitochondrial Trifunctional Protein α-Subunit Enhances Its Stability To Promote Fatty Acid Oxidation and Is Decreased in Nonalcoholic Fatty Liver Disease. Mol Cell Biol 2016; 36:2553-67. [PMID: 27457618 DOI: 10.1128/mcb.00227-16] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 07/19/2016] [Indexed: 02/07/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) has become the most common liver disease, and decreased fatty acid oxidation is one of the important contributors to NAFLD. Mitochondrial trifunctional protein α-subunit (MTPα) functions as a critical enzyme for fatty acid β-oxidation, but whether dysregulation of MTPα is pathogenically connected to NAFLD is poorly understood. We show that MTPα is acetylated at lysine residues 350, 383, and 406 (MTPα-3K), which promotes its protein stability by antagonizing its ubiquitylation on the same three lysines (MTPα-3K) and blocking its subsequent degradation. Sirtuin 4 (SIRT4) has been identified as the deacetylase, deacetylating and destabilizing MTPα. Replacement of MTPα-3K with either MTPα-3KR or MTPα-3KQ inhibits cellular lipid accumulation both in free fatty acid (FFA)-treated alpha mouse liver 12 (AML12) cells and primary hepatocytes and in the livers of high-fat/high-sucrose (HF/HS) diet-fed mice. Moreover, knockdown of SIRT4 could phenocopy the effects of MTPα-3K mutant expression in mouse livers, and MTPα-3K mutants more efficiently attenuate SIRT4-mediated hepatic steatosis in HF/HS diet-fed mice. Importantly, acetylation of both MTPα and MTPα-3K is decreased while SIRT4 is increased in the livers of mice and humans with NAFLD. Our study reveals a novel mechanism of MTPα regulation by acetylation and ubiquitylation and a direct functional link of this regulation to NAFLD.
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Liu X, Zhang J, Ming Y, Chen X, Zeng M, Mao Y. The aggravation of mitochondrial dysfunction in nonalcoholic fatty liver disease accompanied with type 2 diabetes mellitus. Scand J Gastroenterol 2016; 50:1152-9. [PMID: 25877002 DOI: 10.3109/00365521.2015.1030687] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE Nonalcoholic fatty liver disease (NAFLD) is a mitochondrial disease associated with the metabolic syndrome, but few data are available on the mitochondrial dysfunction of NAFLD after the development of type 2 diabetes mellitus (T2DM). We aimed to identify the changes of mitochondrial function in rat livers when T2DM develops after NAFLD. MATERIAL AND METHODS Rat models of nonalcoholic fatty liver (NAFL) and T2DM were established using high-fat diet and streptozocin. Mitochondria were isolated from the livers. The levels of reactive oxygen species (ROS) and mRNA and protein levels of mitochondrial complex IV (COX IV) and carnitine palmitoyltransferase-1 (CPT-1) were assessed in rat livers. The mitochondrial membrane potential (MP), and the enzyme activities of COX IV and CPT-1 were measured in isolated mitochondria. RESULTS There were increased ROS, decreased mitochondrial MP, and reduced COX IV and CPT-1 activity in the NAFL and T2DM groups compared with controls (p < 0.05). Compared with NAFL, the T2DM group had higher ROS levels and lower enzyme activity (p < 0.05), but showed no difference in mitochondrial MP. Although COX IV and CPT-1 expression levels in liver decreased in NAFL and T2DM, there was no significant difference between two groups. CONCLUSION This study first identified progressively impaired mitochondrial respiratory chain and β-oxidation in NAFLD when T2DM develops, inducing overproduction of ROS, and finally triggering a vicious circle that leads to the aggravation of mitochondrial dysfunction in NAFLD after development of T2DM.
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Affiliation(s)
- Xiaolin Liu
- Division of Gastroenterology and Hepatology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai Institute of Digestive Disease , Shanghai 200000 , China
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Satapati S, Kucejova B, Duarte JAG, Fletcher JA, Reynolds L, Sunny NE, He T, Nair LA, Livingston KA, Fu X, Merritt ME, Sherry AD, Malloy CR, Shelton JM, Lambert J, Parks EJ, Corbin I, Magnuson MA, Browning JD, Burgess SC. Mitochondrial metabolism mediates oxidative stress and inflammation in fatty liver. J Clin Invest 2015; 125:4447-62. [PMID: 26571396 DOI: 10.1172/jci82204] [Citation(s) in RCA: 283] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 10/08/2015] [Indexed: 02/06/2023] Open
Abstract
Mitochondria are critical for respiration in all tissues; however, in liver, these organelles also accommodate high-capacity anaplerotic/cataplerotic pathways that are essential to gluconeogenesis and other biosynthetic activities. During nonalcoholic fatty liver disease (NAFLD), mitochondria also produce ROS that damage hepatocytes, trigger inflammation, and contribute to insulin resistance. Here, we provide several lines of evidence indicating that induction of biosynthesis through hepatic anaplerotic/cataplerotic pathways is energetically backed by elevated oxidative metabolism and hence contributes to oxidative stress and inflammation during NAFLD. First, in murine livers, elevation of fatty acid delivery not only induced oxidative metabolism, but also amplified anaplerosis/cataplerosis and caused a proportional rise in oxidative stress and inflammation. Second, loss of anaplerosis/cataplerosis via genetic knockdown of phosphoenolpyruvate carboxykinase 1 (Pck1) prevented fatty acid-induced rise in oxidative flux, oxidative stress, and inflammation. Flux appeared to be regulated by redox state, energy charge, and metabolite concentration, which may also amplify antioxidant pathways. Third, preventing elevated oxidative metabolism with metformin also normalized hepatic anaplerosis/cataplerosis and reduced markers of inflammation. Finally, independent histological grades in human NAFLD biopsies were proportional to oxidative flux. Thus, hepatic oxidative stress and inflammation are associated with elevated oxidative metabolism during an obesogenic diet, and this link may be provoked by increased work through anabolic pathways.
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42
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Differential reduction in cardiac and liver monolysocardiolipin acyltransferase-1 and reduction in cardiac and liver tetralinoleoyl-cardiolipin in the α-subunit of trifunctional protein heterozygous knockout mice. Biochem J 2015; 471:123-9. [PMID: 26251360 DOI: 10.1042/bj20150648] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 08/04/2015] [Indexed: 12/19/2022]
Abstract
The contribution of α-subunit of trifunctional protein (αTFP) to cardiolipin (CL) (diphosphatidylglycerol) remodelling and mitochondrial supercomplex formation was examined in heart and liver mitochondria from wild-type (WT) and αTFP heterozygous knockout [Mtpa(+/-)] mice. Mtpa(+/-) mouse heart and liver exhibited an approximate 55% and 50% reduction in αTFP protein expression compared with WT respectively. Monolysocardiolipin (MLCL) acyltransferase (MLCL AT)-1 protein derived from αTFP was reduced by 30% in Mtpa(+/-) mouse heart but not in liver compared with WT. In vitro acylation of MLCL was significantly reduced in heart but not in liver mitochondria of Mtpa(+/-) mice compared with WT. CL mass was reduced and significant reductions in linoleate-containing CL species, in particular tetralinoleoyl-CL (L4-CL) and trilinoleoyl-CL (L3-MLCL) species, were observed in heart and liver mitochondria of Mtpa(+/-) mice compared with WT. Cardiac and liver mitochondrial supercomplex assembly and NADH dehydrogenase (complex I) activity within these supercomplexes were unaltered in both Mtpa(+/-) mouse heart and Mtpa(+/-) mouse liver compared with WT. The results indicate that αTFP may modulate CL molecular species composition in murine heart and liver. In addition, L4-CL might not be an essential requirement for mitochondrial supercomplex assembly.
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Aroor AR, Habibi J, Ford DA, Nistala R, Lastra G, Manrique C, Dunham MM, Ford KD, Thyfault JP, Parks EJ, Sowers JR, Rector RS. Dipeptidyl peptidase-4 inhibition ameliorates Western diet-induced hepatic steatosis and insulin resistance through hepatic lipid remodeling and modulation of hepatic mitochondrial function. Diabetes 2015; 64:1988-2001. [PMID: 25605806 PMCID: PMC4439570 DOI: 10.2337/db14-0804] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 01/12/2015] [Indexed: 02/07/2023]
Abstract
Novel therapies are needed for treating the increasing prevalence of hepatic steatosis in Western populations. In this regard, dipeptidyl peptidase-4 (DPP-4) inhibitors have recently been reported to attenuate the development of hepatic steatosis, but the potential mechanisms remain poorly defined. In the current study, 4-week-old C57Bl/6 mice were fed a high-fat/high-fructose Western diet (WD) or a WD containing the DPP-4 inhibitor, MK0626, for 16 weeks. The DPP-4 inhibitor prevented WD-induced hepatic steatosis and reduced hepatic insulin resistance by enhancing insulin suppression of hepatic glucose output. WD-induced accumulation of hepatic triacylglycerol (TAG) and diacylglycerol (DAG) content was significantly attenuated with DPP-4 inhibitor treatment. In addition, MK0626 significantly reduced mitochondrial incomplete palmitate oxidation and increased indices of pyruvate dehydrogenase activity, TCA cycle flux, and hepatic TAG secretion. Furthermore, DPP-4 inhibition rescued WD-induced decreases in hepatic PGC-1α and CPT-1 mRNA expression and hepatic Sirt1 protein content. Moreover, plasma uric acid levels in mice fed the WD were decreased after MK0626 treatment. These studies suggest that DPP-4 inhibition ameliorates hepatic steatosis and insulin resistance by suppressing hepatic TAG and DAG accumulation through enhanced mitochondrial carbohydrate utilization and hepatic TAG secretion/export with a concomitant reduction of uric acid production.
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Affiliation(s)
- Annayya R Aroor
- Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Missouri, Columbia, MO Diabetes and Cardiovascular Center, University of Missouri, Columbia, MO
| | - Javad Habibi
- Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Missouri, Columbia, MO Diabetes and Cardiovascular Center, University of Missouri, Columbia, MO
| | - David A Ford
- Department of Biochemistry and Molecular Biology, Saint Louis University, St. Louis, MO Center for Cardiovascular Research, Saint Louis University, St. Louis, MO
| | - Ravi Nistala
- Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Missouri, Columbia, MO Diabetes and Cardiovascular Center, University of Missouri, Columbia, MO
| | - Guido Lastra
- Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Missouri, Columbia, MO Diabetes and Cardiovascular Center, University of Missouri, Columbia, MO
| | - Camila Manrique
- Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Missouri, Columbia, MO Diabetes and Cardiovascular Center, University of Missouri, Columbia, MO
| | - Merlow M Dunham
- Department of Biochemistry and Molecular Biology, Saint Louis University, St. Louis, MO Center for Cardiovascular Research, Saint Louis University, St. Louis, MO
| | - Kaitlin D Ford
- Department of Biochemistry and Molecular Biology, Saint Louis University, St. Louis, MO Center for Cardiovascular Research, Saint Louis University, St. Louis, MO
| | - John P Thyfault
- Gastroenterology and Hepatology, Department of Medicine, University of Missouri, Columbia, MO Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
| | - Elizabeth J Parks
- Gastroenterology and Hepatology, Department of Medicine, University of Missouri, Columbia, MO Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
| | - James R Sowers
- Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Missouri, Columbia, MO Diabetes and Cardiovascular Center, University of Missouri, Columbia, MO Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO
| | - R Scott Rector
- Gastroenterology and Hepatology, Department of Medicine, University of Missouri, Columbia, MO Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
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Camps J, Joven J. Chemokine ligand 2 and paraoxonase-1 in non-alcoholic fatty liver disease: The search for alternative causative factors. World J Gastroenterol 2015; 21:2875-2882. [PMID: 25780284 PMCID: PMC4356906 DOI: 10.3748/wjg.v21.i10.2875] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 09/03/2014] [Accepted: 09/30/2014] [Indexed: 02/06/2023] Open
Abstract
The incidence and prevalence of non-alcoholic fatty liver disease (NAFLD) is constantly increasing. Despite this is apparently associated with the growing increase in obesity, insulin resistance and obesity-related metabolic disturbances their presence is not a necessary or sufficient condition to explain the accumulation of fat in the liver. Conversely, NAFLD is a predictor of other metabolic risks. NAFLD is currently the most frequent chronic liver disease but should not be considered benign or anecdotic because a considerable proportion of patients with NAFLD progress to cirrhosis and end-stage liver disease. Consequently, the search for alternative molecular mechanisms with therapeutic implications in NAFLD and associated disorders deserves a careful consideration. Mitochondria are possible targets as these organelles generate energy from nutrient oxidation. Some findings, generated in patients with extreme obesity and in murine models, support the notion that NAFLD could be a mitochondrial disease. This is plausible because mitochondrial dysfunction affects the accumulation of lipids in hepatocytes and promotes lipid peroxidation, the production of reactive oxygen species, the release of cytokines causing inflammation and cell death. Here we discuss basic research and mechanistic studies targeting the role of chemokine ligand 2 in liver inflammation and that of the paraoxonases in the oxidative stress. Their combination and association with mitochondrial dysfunction may uncover mechanisms underlying the progression of NAFLD and may help to identify novel therapeutic targets.
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Nassir F, Rector RS, Hammoud GM, Ibdah JA. Pathogenesis and Prevention of Hepatic Steatosis. Gastroenterol Hepatol (N Y) 2015; 11:167-175. [PMID: 27099587 PMCID: PMC4836586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Hepatic steatosis is defined as intrahepatic fat of at least 5% of liver weight. Simple accumulation of triacylglycerols in the liver could be hepatoprotective; however, prolonged hepatic lipid storage may lead to liver metabolic dysfunction, inflammation, and advanced forms of nonalcoholic fatty liver disease. Nonalcoholic hepatic steatosis is associated with obesity, type 2 diabetes, and dyslipidemia. Several mechanisms are involved in the accumulation of intrahepatic fat, including increased flux of fatty acids to the liver, increased de novo lipogenesis, and/or reduced clearance through β-oxidation or very-low-density lipoprotein secretion. This article summarizes the mechanisms involved in the accumulation of triacylglycerols in the liver, the clinical implications, and the prevention of hepatic steatosis, with a focus on the role of mitochondrial function and lifestyle modifications.
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Affiliation(s)
- Fatiha Nassir
- Dr Nassir is an assistant research professor of medicine in the Division of Gastroenterology and Hepatology at the University of Missouri School of Medicine in Columbia, Missouri. Dr Rector is an assistant professor of medicine in the Division of Gastroenterology and Hepatology and the Department of Nutrition and Exercise Physiology at the University of Missouri School of Medicine; he is also a research health scientist in the Research Service at the Harry S. Truman Memorial Veterans' Hospital in Columbia, Missouri. Dr Hammoud is an associate professor of clinical medicine in the Division of Gastroenterology and Hepatol ogy at the University of Missouri School of Medicine. Dr Ibdah is a professor of medicine in the Division of Gastroenterology and Hepatology and the Department of Nutrition and Exercise Physiology at the University of Missouri School of Medicine, where he is also the director of the Division of Gastroenterology and Hepatology; in addition, he is a research health scientist in the Research Service at the Harry S. Truman Memorial Veterans' Hospital
| | - R Scott Rector
- Dr Nassir is an assistant research professor of medicine in the Division of Gastroenterology and Hepatology at the University of Missouri School of Medicine in Columbia, Missouri. Dr Rector is an assistant professor of medicine in the Division of Gastroenterology and Hepatology and the Department of Nutrition and Exercise Physiology at the University of Missouri School of Medicine; he is also a research health scientist in the Research Service at the Harry S. Truman Memorial Veterans' Hospital in Columbia, Missouri. Dr Hammoud is an associate professor of clinical medicine in the Division of Gastroenterology and Hepatol ogy at the University of Missouri School of Medicine. Dr Ibdah is a professor of medicine in the Division of Gastroenterology and Hepatology and the Department of Nutrition and Exercise Physiology at the University of Missouri School of Medicine, where he is also the director of the Division of Gastroenterology and Hepatology; in addition, he is a research health scientist in the Research Service at the Harry S. Truman Memorial Veterans' Hospital
| | - Ghassan M Hammoud
- Dr Nassir is an assistant research professor of medicine in the Division of Gastroenterology and Hepatology at the University of Missouri School of Medicine in Columbia, Missouri. Dr Rector is an assistant professor of medicine in the Division of Gastroenterology and Hepatology and the Department of Nutrition and Exercise Physiology at the University of Missouri School of Medicine; he is also a research health scientist in the Research Service at the Harry S. Truman Memorial Veterans' Hospital in Columbia, Missouri. Dr Hammoud is an associate professor of clinical medicine in the Division of Gastroenterology and Hepatol ogy at the University of Missouri School of Medicine. Dr Ibdah is a professor of medicine in the Division of Gastroenterology and Hepatology and the Department of Nutrition and Exercise Physiology at the University of Missouri School of Medicine, where he is also the director of the Division of Gastroenterology and Hepatology; in addition, he is a research health scientist in the Research Service at the Harry S. Truman Memorial Veterans' Hospital
| | - Jamal A Ibdah
- Dr Nassir is an assistant research professor of medicine in the Division of Gastroenterology and Hepatology at the University of Missouri School of Medicine in Columbia, Missouri. Dr Rector is an assistant professor of medicine in the Division of Gastroenterology and Hepatology and the Department of Nutrition and Exercise Physiology at the University of Missouri School of Medicine; he is also a research health scientist in the Research Service at the Harry S. Truman Memorial Veterans' Hospital in Columbia, Missouri. Dr Hammoud is an associate professor of clinical medicine in the Division of Gastroenterology and Hepatol ogy at the University of Missouri School of Medicine. Dr Ibdah is a professor of medicine in the Division of Gastroenterology and Hepatology and the Department of Nutrition and Exercise Physiology at the University of Missouri School of Medicine, where he is also the director of the Division of Gastroenterology and Hepatology; in addition, he is a research health scientist in the Research Service at the Harry S. Truman Memorial Veterans' Hospital
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Zhang C, Hwarng G, Cooper DE, Grevengoed TJ, Eaton JM, Natarajan V, Harris TE, Coleman RA. Inhibited insulin signaling in mouse hepatocytes is associated with increased phosphatidic acid but not diacylglycerol. J Biol Chem 2014; 290:3519-28. [PMID: 25512376 DOI: 10.1074/jbc.m114.602789] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Although an elevated triacylglycerol content in non-adipose tissues is often associated with insulin resistance, the mechanistic relationship remains unclear. The data support roles for intermediates in the glycerol-3-phosphate pathway of triacylglycerol synthesis: diacylglycerol (DAG), which may cause insulin resistance in liver by activating PKCϵ, and phosphatidic acid (PA), which inhibits insulin action in hepatocytes by disrupting the assembly of mTOR and rictor. To determine whether increases in DAG and PA impair insulin signaling when produced by pathways other than that of de novo synthesis, we examined primary mouse hepatocytes after enzymatically manipulating the cellular content of DAG or PA. Overexpressing phospholipase D1 or phospholipase D2 inhibited insulin signaling and was accompanied by an elevated cellular content of total PA, without a change in total DAG. Overexpression of diacylglycerol kinase-θ inhibited insulin signaling and was accompanied by an elevated cellular content of total PA and a decreased cellular content of total DAG. Overexpressing glycerol-3-phosphate acyltransferase-1 or -4 inhibited insulin signaling and increased the cellular content of both PA and DAG. Insulin signaling impairment caused by overexpression of phospholipase D1/D2 or diacylglycerol kinase-θ was always accompanied by disassociation of mTOR/rictor and reduction of mTORC2 kinase activity. However, although the protein ratio of membrane to cytosolic PKCϵ increased, PKC activity itself was unaltered. These data suggest that PA, but not DAG, is associated with impaired insulin action in mouse hepatocytes.
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Affiliation(s)
- Chongben Zhang
- From the Department of Nutrition, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Gwen Hwarng
- From the Department of Nutrition, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Daniel E Cooper
- From the Department of Nutrition, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Trisha J Grevengoed
- From the Department of Nutrition, University of North Carolina, Chapel Hill, North Carolina 27599
| | - James M Eaton
- the Department of Pharmacology, University of Virginia Health System, Charlottesville, Virginia 22908, and
| | - Viswanathan Natarajan
- the Departments of Pharmacology & Medicine, College of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612
| | - Thurl E Harris
- the Department of Pharmacology, University of Virginia Health System, Charlottesville, Virginia 22908, and
| | - Rosalind A Coleman
- From the Department of Nutrition, University of North Carolina, Chapel Hill, North Carolina 27599,
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Gruben N, Shiri-Sverdlov R, Koonen DPY, Hofker MH. Nonalcoholic fatty liver disease: A main driver of insulin resistance or a dangerous liaison? Biochim Biophys Acta Mol Basis Dis 2014; 1842:2329-2343. [PMID: 25128743 DOI: 10.1016/j.bbadis.2014.08.004] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 08/02/2014] [Accepted: 08/07/2014] [Indexed: 12/17/2022]
Abstract
Insulin resistance is one of the key components of the metabolic syndrome and it eventually leads to the development of type 2 diabetes, making it one of the biggest medical problems of modern society. Nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) are tightly associated with insulin resistance. While it is fairly clear that insulin resistance causes hepatic steatosis, it is not known if NAFLD causes insulin resistance. Hepatic inflammation and lipid accumulation are believed to be the main drivers of hepatic insulin resistance in NAFLD. Here we give an overview of the evidence linking hepatic lipid accumulation to the development of insulin resistance, including the accumulation of triacylglycerol and lipid metabolites, such as diacylglycerol and ceramides. In particular, we discuss the role of obesity in this relation by reviewing the current evidence in terms of the reported changes in body weight and/or adipose tissue mass. We further discuss whether the activation or inhibition of inflammatory pathways, Kupffer cells and other immune cells influences the development of insulin resistance. We show that, in contrast to what is commonly believed, neither hepatic steatosis nor hepatic inflammation is sufficient to cause insulin resistance. Many studies show that obesity cannot be ignored as an underlying factor in this relationship and NAFLD is therefore less likely to be one of the main drivers of insulin resistance.
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Affiliation(s)
- Nanda Gruben
- University of Groningen, University Medical Center Groningen, Department of Pediatrics, Molecular Genetics Section, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
| | - Ronit Shiri-Sverdlov
- Maastricht University, Department of Molecular Genetics, PO Box 616, 6200 MD Maastricht, The Netherlands.
| | - Debby P Y Koonen
- University of Groningen, University Medical Center Groningen, Department of Pediatrics, Molecular Genetics Section, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
| | - Marten H Hofker
- University of Groningen, University Medical Center Groningen, Department of Pediatrics, Molecular Genetics Section, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
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Okazaki I, Noro T, Tsutsui N, Yamanouchi E, Kuroda H, Nakano M, Yokomori H, Inagaki Y. Fibrogenesis and Carcinogenesis in Nonalcoholic Steatohepatitis (NASH): Involvement of Matrix Metalloproteinases (MMPs) and Tissue Inhibitors of Metalloproteinase (TIMPs). Cancers (Basel) 2014; 6:1220-55. [PMID: 24978432 PMCID: PMC4190539 DOI: 10.3390/cancers6031220] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 04/24/2014] [Accepted: 05/15/2014] [Indexed: 01/18/2023] Open
Abstract
Nonalcoholic steatohepatitis (NASH) is emerging worldwide because life-styles have changed to include much over-eating and less physical activity. The clinical and pathophysiological features of NASH are very different from those of HBV- and HCV-chronic liver diseases. The prognosis of NASH is worse among those with nonalcoholic fatty liver diseases (NAFLD), and some NASH patients show HCC with or without cirrhosis. In the present review we discuss fibrogenesis and the relationship between fibrosis and HCC occurrence in NASH to clarify the role of MMPs and TIMPs in both mechanisms. Previously we proposed MMP and TIMP expression in the multi-step occurrence of HCC from the literature based on viral-derived HCC. We introduce again these expressions during hepatocarcinogenesis and compare them to those in NASH-derived HCC, although the relationship with hepatic stem/progenitor cells (HPCs) invasion remains unknown. Signal transduction of MMPs and TIMPs is also discussed because it is valuable for the prevention and treatment of NASH and NASH-derived HCC.
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Affiliation(s)
- Isao Okazaki
- Department of Internal Medicine, Sanno Hospital, International University of Health and Welfare, Tokyo 107-0052, Japan.
| | - Takuji Noro
- Department of Surgery, International University of Health and Welfare Hospital, Tochigi 329-2763, Japan.
| | - Nobuhiro Tsutsui
- Department of Surgery, International University of Health and Welfare Hospital, Tochigi 329-2763, Japan.
| | - Eigoro Yamanouchi
- Department of Radiology, International University of Health and Welfare Hospital, Tochigi 329-2763, Japan.
| | - Hajime Kuroda
- Department of Pathology, International University of Health and Welfare Hospital, Tochigi 329-2763, Japan.
| | - Masayuki Nakano
- Department of Pathology, Ofuna Chuo Hospital, Kanagawa 247-0056, Japan.
| | - Hiroaki Yokomori
- Department of Internal Medicine, Kitasato University Medical Center, Saitama 364-8501, Japan.
| | - Yutaka Inagaki
- Department of Regenerative Medicine, Tokai University School of Medicine and Institute of Medical Sciences, Isehara 259-1193, Japan.
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Nassir F, Ibdah JA. Role of mitochondria in nonalcoholic fatty liver disease. Int J Mol Sci 2014; 15:8713-42. [PMID: 24837835 PMCID: PMC4057755 DOI: 10.3390/ijms15058713] [Citation(s) in RCA: 240] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 05/04/2014] [Accepted: 05/07/2014] [Indexed: 12/15/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) affects about 30% of the general population in the United States and includes a spectrum of disease that includes simple steatosis, non-alcoholic steatohepatitis (NASH), fibrosis and cirrhosis. Significant insight has been gained into our understanding of the pathogenesis of NALFD; however the key metabolic aberrations underlying lipid accumulation in hepatocytes and the progression of NAFLD remain to be elucidated. Accumulating and emerging evidence indicate that hepatic mitochondria play a critical role in the development and pathogenesis of steatosis and NAFLD. Here, we review studies that document a link between the pathogenesis of NAFLD and hepatic mitochondrial dysfunction with particular focus on new insights into the role of impaired fatty acid oxidation, the transcription factor peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), and sirtuins in development and progression of NAFLD.
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Affiliation(s)
- Fatiha Nassir
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of Missouri, Columbia, MO 65212, USA.
| | - Jamal A Ibdah
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of Missouri, Columbia, MO 65212, USA.
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