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Kettunen S, Suoranta T, Beikverdi S, Heikkilä M, Slita A, Räty I, Ylä-Herttuala E, Öörni K, Ruotsalainen AK, Ylä-Herttuala S. Deletion of the Murine Ortholog of the Human 9p21.3 Locus Leads to Insulin Resistance and Obesity in Hypercholesterolemic Mice. Cells 2024; 13:983. [PMID: 38891115 PMCID: PMC11171903 DOI: 10.3390/cells13110983] [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: 04/25/2024] [Revised: 05/23/2024] [Accepted: 06/04/2024] [Indexed: 06/21/2024] Open
Abstract
The 9p21.3 genomic locus is a hot spot for disease-associated single-nucleotide polymorphisms (SNPs), and its strongest associations are with coronary artery disease (CAD). The disease-associated SNPs are located within the sequence of a long noncoding RNA ANRIL, which potentially contributes to atherogenesis by regulating vascular cell stress and proliferation, but also affects pancreatic β-cell proliferation. Altered expression of a neighboring gene, CDKN2B, has been also recognized to correlate with obesity and hepatic steatosis in people carrying the risk SNPs. In the present study, we investigated the impact of 9p21.3 on obesity accompanied by hyperlipidemia in mice carrying a deletion of the murine ortholog for the 9p21.3 (Chr4Δ70/Δ70) risk locus in hyperlipidemic Ldlr-/-ApoB100/100 background. The Chr4Δ70/Δ70 mice showed decreased mRNA expression of insulin receptors in white adipose tissue already at a young age, which developed into insulin resistance and obesity by aging. In addition, the Sirt1-Ppargc1a-Ucp2 pathway was downregulated together with the expression of Cdkn2b, specifically in the white adipose tissue in Chr4Δ70/Δ70 mice. These results suggest that the 9p21.3 locus, ANRIL lncRNA, and their murine orthologues may regulate the key energy metabolism pathways in a white adipose tissue-specific manner in the presence of hypercholesterolemia, thus contributing to the pathogenesis of metabolic syndrome.
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Affiliation(s)
- Sanna Kettunen
- A.I. Virtanen Institute, University of Eastern Finland, 70210 Kuopio, Finland; (S.K.); (T.S.); (S.B.); (M.H.); (A.S.); (I.R.); (E.Y.-H.); (S.Y.-H.)
| | - Tuisku Suoranta
- A.I. Virtanen Institute, University of Eastern Finland, 70210 Kuopio, Finland; (S.K.); (T.S.); (S.B.); (M.H.); (A.S.); (I.R.); (E.Y.-H.); (S.Y.-H.)
| | - Sadegh Beikverdi
- A.I. Virtanen Institute, University of Eastern Finland, 70210 Kuopio, Finland; (S.K.); (T.S.); (S.B.); (M.H.); (A.S.); (I.R.); (E.Y.-H.); (S.Y.-H.)
| | - Minja Heikkilä
- A.I. Virtanen Institute, University of Eastern Finland, 70210 Kuopio, Finland; (S.K.); (T.S.); (S.B.); (M.H.); (A.S.); (I.R.); (E.Y.-H.); (S.Y.-H.)
| | - Anna Slita
- A.I. Virtanen Institute, University of Eastern Finland, 70210 Kuopio, Finland; (S.K.); (T.S.); (S.B.); (M.H.); (A.S.); (I.R.); (E.Y.-H.); (S.Y.-H.)
| | - Iida Räty
- A.I. Virtanen Institute, University of Eastern Finland, 70210 Kuopio, Finland; (S.K.); (T.S.); (S.B.); (M.H.); (A.S.); (I.R.); (E.Y.-H.); (S.Y.-H.)
| | - Elias Ylä-Herttuala
- A.I. Virtanen Institute, University of Eastern Finland, 70210 Kuopio, Finland; (S.K.); (T.S.); (S.B.); (M.H.); (A.S.); (I.R.); (E.Y.-H.); (S.Y.-H.)
- Imaging Center, Kuopio University Hospital, 70200 Kuopio, Finland
| | | | - Anna-Kaisa Ruotsalainen
- A.I. Virtanen Institute, University of Eastern Finland, 70210 Kuopio, Finland; (S.K.); (T.S.); (S.B.); (M.H.); (A.S.); (I.R.); (E.Y.-H.); (S.Y.-H.)
| | - Seppo Ylä-Herttuala
- A.I. Virtanen Institute, University of Eastern Finland, 70210 Kuopio, Finland; (S.K.); (T.S.); (S.B.); (M.H.); (A.S.); (I.R.); (E.Y.-H.); (S.Y.-H.)
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Fermaintt CS, Wacker SA. Malate dehydrogenase as a multi-purpose target for drug discovery. Essays Biochem 2024:EBC20230081. [PMID: 38818725 DOI: 10.1042/ebc20230081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 05/15/2024] [Accepted: 05/17/2024] [Indexed: 06/01/2024]
Abstract
Malate dehydrogenase (MDH) enzymes play critical roles in cellular metabolism, facilitating the reversible conversion of malate to oxaloacetate using NAD+/NADH as a cofactor. The two human isoforms of MDH have roles in the citric acid cycle and the malate-aspartate shuttle, and thus both are key enzymes in aerobic respiration as well as regenerating the pool of NAD+ used in glycolysis. This review highlights the potential of MDH as a therapeutic drug target in various diseases, including metabolic and neurological disorders, cancer, and infectious diseases. The most promising molecules for targeting MDH have been examined in the context of human malignancies, where MDH is frequently overexpressed. Recent studies have led to the identification of several antagonists, some of which are broad MDH inhibitors while others have selectivity for either of the two human MDH isoforms. Other promising compounds have been studied in the context of parasitic MDH, as inhibiting the function of the enzyme could selectively kill the parasite. Research is ongoing with these chemical scaffolds to develop more effective small-molecule drug leads that would have great potential for clinical applications.
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Affiliation(s)
- Charles S Fermaintt
- Department of Chemistry and Biochemistry, University of the Incarnate Word, San Antonio, TX, U.S.A
| | - Sarah A Wacker
- Department of Chemistry and Biochemistry, Manhattan College, The Bronx, NY, U.S.A
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Flensted-Jensen M, Oró D, Rørbeck EA, Zhang C, Madsen MR, Madsen AN, Norlin J, Feigh M, Larsen S, Hansen HH. Dietary intervention reverses molecular markers of hepatocellular senescence in the GAN diet-induced obese and biopsy-confirmed mouse model of NASH. BMC Gastroenterol 2024; 24:59. [PMID: 38308212 PMCID: PMC10835988 DOI: 10.1186/s12876-024-03141-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 01/18/2024] [Indexed: 02/04/2024] Open
Abstract
BACKGROUND Hepatocellular senescence may be a causal factor in the development and progression of non-alcoholic steatohepatitis (NASH). The most effective currently available treatment for NASH is lifestyle intervention, including dietary modification. This study aimed to evaluate the effects of dietary intervention on hallmarks of NASH and molecular signatures of hepatocellular senescence in the Gubra-Amylin NASH (GAN) diet-induced obese (DIO) and biopsy-confirmed mouse model of NASH. METHODS GAN DIO-NASH mice with liver biopsy-confirmed NASH and fibrosis received dietary intervention by switching to chow feeding (chow reversal) for 8, 16 or 24 weeks. Untreated GAN DIO-NASH mice and chow-fed C57BL/6J mice served as controls. Pre-to-post liver biopsy histology was performed for within-subject evaluation of NAFLD Activity Score and fibrosis stage. Terminal endpoints included blood/liver biochemistry, quantitative liver histology, mitochondrial respiration and RNA sequencing. RESULTS Chow-reversal promoted substantial benefits on metabolic outcomes and liver histology, as demonstrated by robust weight loss, complete resolution of hepatomegaly, hypercholesterolemia, elevated transaminase levels and hepatic steatosis in addition to attenuation of inflammatory markers. Notably, all DIO-NASH mice demonstrated ≥ 2 point significant improvement in NAFLD Activity Score following dietary intervention. While not improving fibrosis stage, chow-reversal reduced quantitative fibrosis markers (PSR, collagen 1a1, α-SMA), concurrent with improved liver mitochondrial respiration, complete reversal of p21 overexpression, lowered γ-H2AX levels and widespread suppression of gene expression markers of hepatocellular senescence. CONCLUSIONS Dietary intervention (chow reversal) substantially improves metabolic, biochemical and histological hallmarks of NASH and fibrosis in GAN DIO-NASH mice. These benefits were reflected by progressive clearance of senescent hepatocellular cells, making the model suitable for profiling potential senotherapeutics in preclinical drug discovery for NASH.
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Affiliation(s)
- Mathias Flensted-Jensen
- Gubra, Hørsholm Kongevej 11B, 2970, Hørsholm, Denmark
- Xlab, Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen, Denmark
| | - Denise Oró
- Gubra, Hørsholm Kongevej 11B, 2970, Hørsholm, Denmark
| | | | - Chen Zhang
- Gubra, Hørsholm Kongevej 11B, 2970, Hørsholm, Denmark
- Present address: Novo Nordisk A/S, Beijing, China
| | | | | | - Jenny Norlin
- Liver Disease Research, Novo Nordisk A/S, Måløv, Denmark
| | - Michael Feigh
- Gubra, Hørsholm Kongevej 11B, 2970, Hørsholm, Denmark
| | - Steen Larsen
- Xlab, Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen, Denmark
- Clinical Research Centre, Medical University of Bialystok, Bialystok, Poland
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Bosso M, Haddad D, Al Madhoun A, Al-Mulla F. Targeting the Metabolic Paradigms in Cancer and Diabetes. Biomedicines 2024; 12:211. [PMID: 38255314 PMCID: PMC10813379 DOI: 10.3390/biomedicines12010211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 01/09/2024] [Accepted: 01/11/2024] [Indexed: 01/24/2024] Open
Abstract
Dysregulated metabolic dynamics are evident in both cancer and diabetes, with metabolic alterations representing a facet of the myriad changes observed in these conditions. This review delves into the commonalities in metabolism between cancer and type 2 diabetes (T2D), focusing specifically on the contrasting roles of oxidative phosphorylation (OXPHOS) and glycolysis as primary energy-generating pathways within cells. Building on earlier research, we explore how a shift towards one pathway over the other serves as a foundational aspect in the development of cancer and T2D. Unlike previous reviews, we posit that this shift may occur in seemingly opposing yet complementary directions, akin to the Yin and Yang concept. These metabolic fluctuations reveal an intricate network of underlying defective signaling pathways, orchestrating the pathogenesis and progression of each disease. The Warburg phenomenon, characterized by the prevalence of aerobic glycolysis over minimal to no OXPHOS, emerges as the predominant metabolic phenotype in cancer. Conversely, in T2D, the prevailing metabolic paradigm has traditionally been perceived in terms of discrete irregularities rather than an OXPHOS-to-glycolysis shift. Throughout T2D pathogenesis, OXPHOS remains consistently heightened due to chronic hyperglycemia or hyperinsulinemia. In advanced insulin resistance and T2D, the metabolic landscape becomes more complex, featuring differential tissue-specific alterations that affect OXPHOS. Recent findings suggest that addressing the metabolic imbalance in both cancer and diabetes could offer an effective treatment strategy. Numerous pharmaceutical and nutritional modalities exhibiting therapeutic effects in both conditions ultimately modulate the OXPHOS-glycolysis axis. Noteworthy nutritional adjuncts, such as alpha-lipoic acid, flavonoids, and glutamine, demonstrate the ability to reprogram metabolism, exerting anti-tumor and anti-diabetic effects. Similarly, pharmacological agents like metformin exhibit therapeutic efficacy in both T2D and cancer. This review discusses the molecular mechanisms underlying these metabolic shifts and explores promising therapeutic strategies aimed at reversing the metabolic imbalance in both disease scenarios.
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Affiliation(s)
- Mira Bosso
- Department of Pathology, Faculty of Medicine, Health Science Center, Kuwait University, Safat 13110, Kuwait
| | - Dania Haddad
- Department of Genetics and Bioinformatics, Dasman Diabetes Institute, Dasman 15462, Kuwait; (D.H.); (A.A.M.)
| | - Ashraf Al Madhoun
- Department of Genetics and Bioinformatics, Dasman Diabetes Institute, Dasman 15462, Kuwait; (D.H.); (A.A.M.)
- Department of Animal and Imaging Core Facilities, Dasman Diabetes Institute, Dasman 15462, Kuwait
| | - Fahd Al-Mulla
- Department of Pathology, Faculty of Medicine, Health Science Center, Kuwait University, Safat 13110, Kuwait
- Department of Genetics and Bioinformatics, Dasman Diabetes Institute, Dasman 15462, Kuwait; (D.H.); (A.A.M.)
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Chen L, Zhou M, Li H, Liu D, Liao P, Zong Y, Zhang C, Zou W, Gao J. Mitochondrial heterogeneity in diseases. Signal Transduct Target Ther 2023; 8:311. [PMID: 37607925 PMCID: PMC10444818 DOI: 10.1038/s41392-023-01546-w] [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: 08/22/2022] [Revised: 02/21/2023] [Accepted: 06/13/2023] [Indexed: 08/24/2023] Open
Abstract
As key organelles involved in cellular metabolism, mitochondria frequently undergo adaptive changes in morphology, components and functions in response to various environmental stresses and cellular demands. Previous studies of mitochondria research have gradually evolved, from focusing on morphological change analysis to systematic multiomics, thereby revealing the mitochondrial variation between cells or within the mitochondrial population within a single cell. The phenomenon of mitochondrial variation features is defined as mitochondrial heterogeneity. Moreover, mitochondrial heterogeneity has been reported to influence a variety of physiological processes, including tissue homeostasis, tissue repair, immunoregulation, and tumor progression. Here, we comprehensively review the mitochondrial heterogeneity in different tissues under pathological states, involving variant features of mitochondrial DNA, RNA, protein and lipid components. Then, the mechanisms that contribute to mitochondrial heterogeneity are also summarized, such as the mutation of the mitochondrial genome and the import of mitochondrial proteins that result in the heterogeneity of mitochondrial DNA and protein components. Additionally, multiple perspectives are investigated to better comprehend the mysteries of mitochondrial heterogeneity between cells. Finally, we summarize the prospective mitochondrial heterogeneity-targeting therapies in terms of alleviating mitochondrial oxidative damage, reducing mitochondrial carbon stress and enhancing mitochondrial biogenesis to relieve various pathological conditions. The possibility of recent technological advances in targeted mitochondrial gene editing is also discussed.
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Affiliation(s)
- Long Chen
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Sciences, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 200031, China
| | - Mengnan Zhou
- Department of Pathogenic Biology, School of Basic Medical Science, China Medical University, Shenyang, 110001, China
| | - Hao Li
- Department of Orthopaedics, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Delin Liu
- Department of Orthopaedics, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Peng Liao
- Department of Orthopaedics, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Yao Zong
- Centre for Orthopaedic Research, Medical School, The University of Western Australia, Nedlands, WA, 6009, Australia
| | - Changqing Zhang
- Department of Orthopaedics, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China.
| | - Weiguo Zou
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Sciences, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 200031, China.
- Institute of Microsurgery on Extremities, and Department of Orthopedic Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China.
| | - Junjie Gao
- Department of Orthopaedics, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China.
- Institute of Microsurgery on Extremities, and Department of Orthopedic Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China.
- Shanghai Sixth People's Hospital Fujian, No. 16, Luoshan Section, Jinguang Road, Luoshan Street, Jinjiang City, Quanzhou, Fujian, China.
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Aghayev M, Arias-Alvarado A, Ilchenko S, Lepp J, Scott I, Chen YR, Zhang GF, Tsai TH, Kasumov T. A high-fat diet increases hepatic mitochondrial turnover through restricted acetylation in a NAFLD mouse model. Am J Physiol Endocrinol Metab 2023; 325:E83-E98. [PMID: 37224468 PMCID: PMC10312330 DOI: 10.1152/ajpendo.00310.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 05/15/2023] [Accepted: 05/16/2023] [Indexed: 05/26/2023]
Abstract
Lysine acetylation of proteins has emerged as a key posttranslational modification (PTM) that regulates mitochondrial metabolism. Acetylation may regulate energy metabolism by inhibiting and affecting the stability of metabolic enzymes and oxidative phosphorylation (OxPhos) subunits. Although protein turnover can be easily measured, due to the low abundance of modified proteins, it has been difficult to evaluate the effect of acetylation on the stability of proteins in vivo. We applied 2H2O-metabolic labeling coupled with immunoaffinity and high-resolution mass spectrometry method to measure the stability of acetylated proteins in mouse liver based on their turnover rates. As a proof-of-concept, we assessed the consequence of high-fat diet (HFD)-induced altered acetylation in protein turnover in LDL receptor-deficient (LDLR-/-) mice susceptible to diet-induced nonalcoholic fatty liver disease (NAFLD). HFD feeding for 12 wk led to steatosis, the early stage of NAFLD. A significant reduction in acetylation of hepatic proteins was observed in NAFLD mice, based on immunoblot analysis and label-free quantification with mass spectrometry. Compared with control mice on a normal diet, NAFLD mice had overall increased turnover rates of hepatic proteins, including mitochondrial metabolic enzymes (0.159 ± 0.079 vs. 0.132 ± 0.068 day-1), suggesting their reduced stability. Also, acetylated proteins had slower turnover rates (increased stability) than native proteins in both groups (0.096 ± 0.056 vs. 0.170 ± 0.059 day-1 in control, and 0.111 ± 0.050 vs. 0.208 ± 0.074 day-1 in NAFLD). Furthermore, association analysis revealed a relationship between the HFD-induced decrease in acetylation and increased turnover rates for hepatic proteins in NAFLD mice. These changes were associated with increased expressions of the hepatic mitochondrial transcriptional factor (TFAM) and complex II subunit without any changes to other OxPhos proteins, suggesting that enhanced mitochondrial biogenesis prevented restricted acetylation-mediated depletion of mitochondrial proteins. We conclude that decreased acetylation of mitochondrial proteins may contribute to adaptive improved hepatic mitochondrial function in the early stages of NAFLD.NEW & NOTEWORTHY This is the first method to quantify acetylome dynamics in vivo. This method revealed acetylation-mediated altered hepatic mitochondrial protein turnover in response to a high-fat diet in a mouse model of NAFLD.
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Affiliation(s)
- Mirjavid Aghayev
- Department of Pharmaceutical Sciences, College of Pharmacy, Northeast Ohio Medical University, Rootstown, Ohio, United States
| | - Andrea Arias-Alvarado
- Department of Pharmaceutical Sciences, College of Pharmacy, Northeast Ohio Medical University, Rootstown, Ohio, United States
| | - Sergei Ilchenko
- Department of Pharmaceutical Sciences, College of Pharmacy, Northeast Ohio Medical University, Rootstown, Ohio, United States
| | - Josephine Lepp
- Department of Pharmaceutical Sciences, College of Pharmacy, Northeast Ohio Medical University, Rootstown, Ohio, United States
| | - Iain Scott
- Cardiology Division, Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States
| | - Yeong-Renn Chen
- Department of Integrative Medical Sciences, College of Medicine, Northeast Ohio Medical University, Rootstown, Ohio, United States
| | - Guo-Fang Zhang
- Division of Endocrinology, Metabolism and Nutrition, Duke Molecular Physiology Institute, Duke University, Durham North Carolina, United States
- Department of Medicine, Duke University, Durham North Carolina, United States
| | - Tsung-Heng Tsai
- Department of Mathematical Sciences, Kent State University, Kent, Ohio, United States
| | - Takhar Kasumov
- Department of Pharmaceutical Sciences, College of Pharmacy, Northeast Ohio Medical University, Rootstown, Ohio, United States
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Heras-Molina A, Núñez Y, Benítez R, Pesántez-Pacheco JL, García-Contreras C, Vázquez-Gómez M, Astiz S, Isabel B, González-Bulnes A, Óvilo C. Hypothalamic transcriptome analysis reveals male-specific differences in molecular pathways related to oxidative phosphorylation between Iberian pig genotypes. PLoS One 2022; 17:e0272775. [PMID: 35972914 PMCID: PMC9380940 DOI: 10.1371/journal.pone.0272775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 07/27/2022] [Indexed: 11/29/2022] Open
Abstract
The hypothalamus is implicated in controlling feeding and adiposity, besides many other physiological functions, and thus can be of great importance in explaining productive differences between lean and fatty pig breeds. The present study aimed to evaluate the hypothalamic transcriptome of pure Iberian (IBxIB) and Large White x Iberian crossbreds (IBxLW) at 60 days-old, produced in a single maternal environment. Results showed the implication of gender and genotype in the hypothalamic transcriptome, with 51 differentially expressed genes (DEGs) between genotypes and 10 DEGs between genders. Fourteen genotype by sex interactions were found, due to a higher genotype effect on transcriptome found in males. In fact, just 31 DEGs were identified when using only females but 158 using only males. A higher expression of genes related to mitochondrial activity in IBxIB male animals (ND3, ND4, ND5, UQCRC2 and ATP6) was found, which was related to a higher oxidative phosphorylation and greater reactive oxygen species and nitric oxide production. IBxLW male animals showed higher expression of SIRT3 regulator, also related to mitochondrial function. When females were analysed, such differences were not found, since only some differences in genes related to the tricarboxylic acid cycle. Thus, the results indicate a significant effect and interaction of the breed and the sex on the hypothalamic transcriptome at this early age.
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Affiliation(s)
- Ana Heras-Molina
- Department of Animal Breeding, INIA-CSIC, Madrid, Spain
- Department of Animal Production, Veterinary Faculty, UCM, Madrid, Spain
- * E-mail:
| | - Yolanda Núñez
- Department of Animal Breeding, INIA-CSIC, Madrid, Spain
| | - Rita Benítez
- Department of Animal Breeding, INIA-CSIC, Madrid, Spain
| | - José Luis Pesántez-Pacheco
- Department of Animal Reproduction, INIA-CSIC, Madrid, Spain
- School of Veterinary Medicine and Zootechnics, Faculty of Agricultural Sciences, UC, Cuenca, Ecuador
| | | | - Marta Vázquez-Gómez
- Department of Animal Production, Veterinary Faculty, UCM, Madrid, Spain
- Nutrition and Obesities: Systemic Approaches Research Unit (NutriOmics), INSERM, Sorbonne Université, Paris, France
| | - Susana Astiz
- Department of Animal Reproduction, INIA-CSIC, Madrid, Spain
| | - Beatriz Isabel
- Department of Animal Production, Veterinary Faculty, UCM, Madrid, Spain
| | - Antonio González-Bulnes
- Department of Animal Reproduction, INIA-CSIC, Madrid, Spain
- Department of Animal Production, Veterinary Faculty, UCH-CEU, Valencia, Spain
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Vachher M, Bansal S, Kumar B, Yadav S, Arora T, Wali NM, Burman A. Contribution of organokines in the development of NAFLD/NASH associated hepatocellular carcinoma. J Cell Biochem 2022; 123:1553-1584. [PMID: 35818831 DOI: 10.1002/jcb.30252] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 03/17/2022] [Accepted: 03/29/2022] [Indexed: 12/16/2022]
Abstract
Globally the incidence of hepatocellular carcinoma (HCC) is on an upsurge. Evidence is accumulating that liver disorders like nonalcoholic fatty liver disease (NAFLD) and its more progressive form nonalcoholic steatohepatitis (NASH) are associated with increased risk of developing HCC. NAFLD has a prevalence of about 25% and 50%-90% in obese population. With the growing burden of obesity epidemic worldwide, HCC presents a major healthcare burden. While cirrhosis is one of the major risk factors of HCC, available literature suggests that NAFLD/NASH associated HCC also develops in minimum or noncirrhotic livers. Therefore, there is an urgent need to understand the pathogenesis and risk factors associated with NAFLD and NASH related HCC that would help in early diagnosis and favorable prognosis of HCC secondary to NAFLD. Adipokines, hepatokines and myokines are factors secreted by adipocytes, hepatocytes and myocytes, respectively, playing essential roles in cellular homeostasis, energy balance and metabolism with autocrine, paracrine and endocrine effects. In this review, we endeavor to focus on the role of these organokines in the pathogenesis of NAFLD/NASH and its progression to HCC to augment the understanding of the factors stimulating hepatocytes to acquire a malignant phenotype. This shall aid in the development of novel therapeutic strategies and tools for early diagnosis of NAFLD/NASH and HCC.
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Affiliation(s)
- Meenakshi Vachher
- Department of Biochemistry, Institute of Home Economics, University of Delhi, Delhi, India
| | - Savita Bansal
- Department of Biochemistry, Institute of Home Economics, University of Delhi, Delhi, India
| | - Bhupender Kumar
- Department of Biochemistry, Institute of Home Economics, University of Delhi, Delhi, India
| | - Sandeep Yadav
- Department of Biochemistry, Institute of Home Economics, University of Delhi, Delhi, India
| | - Taruna Arora
- Department of Biochemistry, Institute of Home Economics, University of Delhi, Delhi, India
| | - Nalini Moza Wali
- Department of Biochemistry, Institute of Home Economics, University of Delhi, Delhi, India
| | - Archana Burman
- Department of Biochemistry, Institute of Home Economics, University of Delhi, Delhi, India
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Reduction of CD8 T cell functionality but not inhibitory capacity by integrase inhibitors. J Virol 2022; 96:e0173021. [PMID: 35019724 DOI: 10.1128/jvi.01730-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Although HIV-specific CD8 T cells are effective in controlling HIV-infection, they fail to clear infection even in the presence of antiretroviral therapy (ART) and cure strategies such as "shock-and-kill". Little is known how ART is contributing to HIV-specific CD8 T cell function and the ability to clear HIV infection. Therefore, we first assessed the cytokine polyfunctionality and proliferation of CD8 T cells from ART-treated HIV+ individuals directly ex vivo and observed a decline in the multifunctional response as well as proliferation indices of these cells in individuals treated with integrase inhibitor (INSTI) based ART regimens compared to both protease inhibitor (PI) and non-nucleoside reverse-transcriptase inhibitor (NNRTI) based regimens. We next co-cultured CD8 T cells with different drugs individually and were able to observe reduced functional properties with significantly decreased ability of CD8 T cells to express IFNγ, MIP1β and TNFα only after treatment with INSTI-based regimens. Furthermore, previously activated and INSTI-treated CD8 T cells demonstrated reduced capacity to express perforin and granzyme B compared to PI and NNRTI treated cells. Unexpectedly, CD8 T cells treated with dolutegravir showed a similar killing ability 7 dpi compared to emtricitabine or rilpivirine treated cells. We next used a live cell imaging assay to determine the migratory capacity of CD8 T cells. Only INSTI-treated cells showed less migratory activity after SDF-1α stimulation compared to NRTI regimens. Our data show that the choice of ART can have a significant impact on CD8 T cell effector functions, but the importance for potential eradication attempts is unknown. Importance Integrase Strand Transfer Inhibitors (INSTI) are recommended by national and international guidelines as a key component of ART in the treatment of HIV-infected patients. In particular, their efficacy, tolerability and low drug-drug interaction profile have made them to the preferred choice as part of the first-line regimen in treatment-naïve individuals. Here, we demonstrate that the choice of ART can have a significant impact on function and metabolism of CD8 T cells. In summary, our study provides first evidence on a significant, negative impact on CD8 T cell effector functions in the presence of two INSTIs, dolutegravir and elvitegravir, which may contribute to the limited success of eradicating HIV-infected cells through "shock-and-kill" strategies. Although our findings are coherent with recent studies highlighting a possible role of dolutegravir in weight gain, further investigations are necessary to fully understand the impact of INSTI-based regimens on the health of the individual during antiretroviral therapy.
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Yu M, Alimujiang M, Hu L, Liu F, Bao Y, Yin J. Berberine alleviates lipid metabolism disorders via inhibition of mitochondrial complex I in gut and liver. Int J Biol Sci 2021; 17:1693-1707. [PMID: 33994854 PMCID: PMC8120465 DOI: 10.7150/ijbs.54604] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 03/24/2021] [Indexed: 12/14/2022] Open
Abstract
This study is to investigate the relationship between berberine (BBR) and mitochondrial complex I in lipid metabolism. BBR reversed high-fat diet-induced obesity, hepatic steatosis, hyperlipidemia and insulin resistance in mice. Fatty acid consumption, β-oxidation and lipogenesis were attenuated in liver after BBR treatment which may be through reduction in SCD1, FABP1, CD36 and CPT1A. BBR promoted fecal lipid excretion, which may result from the reduction in intestinal CD36 and SCD1. Moreover, BBR inhibited mitochondrial complex I-dependent oxygen consumption and ATP synthesis of liver and gut, but no impact on activities of complex II, III and IV. BBR ameliorated mitochondrial swelling, facilitated mitochondrial fusion, and reduced mtDNA and citrate synthase activity. BBR decreased the abundance and diversity of gut microbiome. However, no change in metabolism of recipient mice was observed after fecal microbiota transplantation from BBR treated mice. In primary hepatocytes, BBR and AMPK activator A769662 normalized oleic acid-induced lipid deposition. Although both the agents activated AMPK, BBR decreased oxygen consumption whereas A769662 increased it. Collectively, these findings indicated that BBR repressed complex I in gut and liver and consequently inhibited lipid metabolism which led to alleviation of obesity and fatty liver. This process was independent of intestinal bacteria.
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Affiliation(s)
- Muyu Yu
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Clinical Center for Metabolic Diseases, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Diabetes Institute, 600 Yishan Road, Shanghai, 200233, China
| | - Miriayi Alimujiang
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Clinical Center for Metabolic Diseases, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Diabetes Institute, 600 Yishan Road, Shanghai, 200233, China
| | - Lili Hu
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Clinical Center for Metabolic Diseases, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Diabetes Institute, 600 Yishan Road, Shanghai, 200233, China
| | - Fang Liu
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Clinical Center for Metabolic Diseases, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Diabetes Institute, 600 Yishan Road, Shanghai, 200233, China
| | - Yuqian Bao
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Clinical Center for Metabolic Diseases, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Diabetes Institute, 600 Yishan Road, Shanghai, 200233, China
| | - Jun Yin
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Clinical Center for Metabolic Diseases, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Diabetes Institute, 600 Yishan Road, Shanghai, 200233, China.,Department of Endocrinology and Metabolism, Shanghai Eighth People's Hospital, Shanghai, 200235, China
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11
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Therapeutic potential of mitochondrial uncouplers for the treatment of metabolic associated fatty liver disease and NASH. Mol Metab 2021; 46:101178. [PMID: 33545391 PMCID: PMC8085597 DOI: 10.1016/j.molmet.2021.101178] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 01/18/2021] [Accepted: 01/28/2021] [Indexed: 12/13/2022] Open
Abstract
Background Mitochondrial uncouplers shuttle protons across the inner mitochondrial membrane via a pathway that is independent of adenosine triphosphate (ATP) synthase, thereby uncoupling nutrient oxidation from ATP production and dissipating the proton gradient as heat. While initial toxicity concerns hindered their therapeutic development in the early 1930s, there has been increased interest in exploring the therapeutic potential of mitochondrial uncouplers for the treatment of metabolic diseases. Scope of review In this review, we cover recent advances in the mechanisms by which mitochondrial uncouplers regulate biological processes and disease, with a particular focus on metabolic associated fatty liver disease (MAFLD), nonalcoholic hepatosteatosis (NASH), insulin resistance, and type 2 diabetes (T2D). We also discuss the challenges that remain to be addressed before synthetic and natural mitochondrial uncouplers can successfully enter the clinic. Major conclusions Rodent and non-human primate studies suggest that a myriad of small molecule mitochondrial uncouplers can safely reverse MAFLD/NASH with a wide therapeutic index. Despite this, further characterization of the tissue- and cell-specific effects of mitochondrial uncouplers is needed. We propose targeting the dosing of mitochondrial uncouplers to specific tissues such as the liver and/or developing molecules with self-limiting properties to induce a subtle and sustained increase in mitochondrial inefficiency, thereby avoiding systemic toxicity concerns.
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12
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Alimujiang M, Yu XY, Yu MY, Hou WL, Yan ZH, Yang Y, Bao YQ, Yin J. Enhanced liver but not muscle OXPHOS in diabetes and reduced glucose output by complex I inhibition. J Cell Mol Med 2020; 24:5758-5771. [PMID: 32253813 PMCID: PMC7214161 DOI: 10.1111/jcmm.15238] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 01/14/2020] [Accepted: 02/06/2020] [Indexed: 12/25/2022] Open
Abstract
Mitochondrial function is critical in energy metabolism. To fully capture how the mitochondrial function changes in metabolic disorders, we investigated mitochondrial function in liver and muscle of animal models mimicking different types and stages of diabetes. Type 1 diabetic mice were induced by streptozotocin (STZ) injection. The db/db mice were used as type 2 diabetic model. High-fat diet-induced obese mice represented pre-diabetic stage of type 2 diabetes. Oxidative phosphorylation (OXPHOS) of isolated mitochondria was measured with Clark-type oxygen electrode. Both in early and late stages of type 1 diabetes, liver mitochondrial OXPHOS increased markedly with complex IV-dependent OXPHOS being the most prominent. However, ATP, ADP and AMP contents in the tissue did not change. In pre-diabetes and early stage of type 2 diabetes, liver mitochondrial complex I and II-dependent OXPHOS increased greatly then declined to almost normal at late stage of type 2 diabetes, among which alteration of complex I-dependent OXPHOS was the most significant. In contrast, muscle mitochondrial OXPHOS in HFD, early-stage type 1 and 2 diabetic mice, did not change. In vitro, among inhibitors to each complex, only complex I inhibitor rotenone decreased glucose output in primary hepatocytes without cytotoxicity both in the absence and presence of oleic acid (OA). Rotenone affected cellular energy state and had no effects on cellular and mitochondrial reactive oxygen species production. Taken together, the mitochondrial OXPHOS of liver but not muscle increased in obesity and diabetes, and only complex I inhibition may ameliorate hyperglycaemia via lowering hepatic glucose production.
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Affiliation(s)
- Miriayi Alimujiang
- Department of Endocrinology and Metabolism, Shanghai Clinical Center for Metabolic Diseases, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Diabetes Institute, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Xue-Ying Yu
- Department of Endocrinology and Metabolism, Shanghai Clinical Center for Metabolic Diseases, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Diabetes Institute, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Mu-Yu Yu
- Department of Endocrinology and Metabolism, Shanghai Clinical Center for Metabolic Diseases, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Diabetes Institute, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Wo-Lin Hou
- Department of Endocrinology and Metabolism, Shanghai Clinical Center for Metabolic Diseases, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Diabetes Institute, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Zhong-Hong Yan
- Department of Chemistry, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ying Yang
- Department of Endocrinology and Metabolism, Shanghai Clinical Center for Metabolic Diseases, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Diabetes Institute, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Yu-Qian Bao
- Department of Endocrinology and Metabolism, Shanghai Clinical Center for Metabolic Diseases, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Diabetes Institute, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Jun Yin
- Department of Endocrinology and Metabolism, Shanghai Clinical Center for Metabolic Diseases, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Diabetes Institute, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China.,Department of Endocrinology and Metabolism, Shanghai Eighth People's Hospital, Shanghai, China
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13
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Sun D, Wei Y, Zheng HX, Jin L, Wang J. Contribution of Mitochondrial DNA Variation to Chronic Disease in East Asian Populations. Front Mol Biosci 2019; 6:128. [PMID: 31803756 PMCID: PMC6873657 DOI: 10.3389/fmolb.2019.00128] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 10/29/2019] [Indexed: 12/17/2022] Open
Abstract
Mitochondria are the main producers of energy in eukaryotic cells. Mitochondrial dysfunction is associated with specific mitochondrial DNA (mtDNA) variations (haplogroups), and these variations can contribute to human disease. East Asian populations show enrichment of many mitochondrial haplogroups, including A, B, D, G, M7, M8, M9, N9, R9, and exhibit half of the known haplogroups of worldwide. In this review, we summarize the current research in the field of mtDNA variation and associated disease in East Asian populations and discuss the physiological and pathological relevance of mitochondrial biology. mtDNA haplogroups are associated with various metabolic disorders ascribed to altered oxidative phosphorylation. The same mitochondrial haplogroup can show either a negative or positive association with different diseases. Mitochondrial dynamics, mitophagy, and mitochondrial oxidative stress, ultimately influence susceptibility to various diseases. In addition, mitochondrial retrograde signaling pathways may have profound effects on nuclear-mitochondrial interactions, affecting cellular morphology, and function. Other complex networks including proteostasis, mitochondrial unfolded protein response and reactive oxygen species signaling may also play pivotal roles in metabolic performance.
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Affiliation(s)
- Dayan Sun
- State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China.,Human Phenome Institute, Fudan University, Shanghai, China
| | - Yang Wei
- State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China.,Human Phenome Institute, Fudan University, Shanghai, China
| | - Hong-Xiang Zheng
- Ministry of Education Key Laboratory of Contemporary Anthropology, Department of Anthropology and Human Genetics, School of Life Sciences, Fudan University, Shanghai, China
| | - Li Jin
- State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China.,Human Phenome Institute, Fudan University, Shanghai, China
| | - Jiucun Wang
- State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China.,Human Phenome Institute, Fudan University, Shanghai, China
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14
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Wang J, Xu S, Gao J, Zhang L, Zhang Z, Yang W, Li Y, Liao S, Zhou H, Liu P, Liang B. SILAC-based quantitative proteomic analysis of the livers of spontaneous obese and diabetic rhesus monkeys. Am J Physiol Endocrinol Metab 2018; 315:E294-E306. [PMID: 29664677 DOI: 10.1152/ajpendo.00016.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Type 2 diabetes mellitus (T2DM) is a severe metabolic disorder that affects more than 10% of the population worldwide. Obesity is a major cause of insulin resistance and contributes to the development of T2DM. Liver is an essential metabolic organ that plays crucial roles in the pathogenesis of obesity and diabetes. However, the underlying mechanisms of liver in the transition of obesity to diabetes are not fully understood. The nonhuman primate rhesus monkey is an appropriate animal for research of human diseases. Here, we first screened and selected three individuals of spontaneously diabetic rhesus monkeys. Interestingly, the diabetic monkeys were obese with a high body mass index at the beginning, but gradually lost their body weight during one year of observation. Furthermore, we performed stable isotope labeling with amino acids in cell culture-based quantitative proteomics to identify proteins and signaling pathways with altered expression in the liver of obese and diabetic monkeys. In total, 3,509 proteins were identified and quantified, of which 185 proteins displayed an altered expression level. Gene ontology analysis revealed that the expression of proteins involved in fatty acids β-oxidation and galactose metabolism was increased in obese monkeys; while proteins involved in oxidative phosphorylation and branched chain amino acid (BCAA) degradation were upregulated in diabetic monkeys. In addition, we observed mild apoptosis in the liver of diabetic monkeys, suggesting liver injury at the late onset of diabetes. Taken together, our liver proteomics may reveal a distinct metabolic transition from fatty acids β-oxidation in obese monkey to BCAA degradation in diabetic monkeys.
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Affiliation(s)
- Junlong Wang
- College of Pharmaceutical Sciences, Soochow University , Suzhou , China
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences , Kunming , China
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences , Kunming , China
| | - Shimeng Xu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences , Beijing , China
| | - Jing Gao
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences , Shanghai , China
| | - Linqiang Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences , Kunming , China
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences , Kunming , China
| | - Zhiguo Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences , Kunming , China
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences , Kunming , China
| | - Wenhui Yang
- Key Laboratory of Cardiovascular Disease of Yunnan Province, Department of Geriatrics, Yan'an Affiliated Hospital of Kunming Medical University , Kunming , China
| | - Yunhai Li
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences , Kunming , China
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences , Kunming , China
| | - Shasha Liao
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences , Kunming , China
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences , Kunming , China
| | - Hu Zhou
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences , Shanghai , China
| | - Pingsheng Liu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences , Beijing , China
| | - Bin Liang
- College of Pharmaceutical Sciences, Soochow University , Suzhou , China
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences , Kunming , China
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences , Kunming , China
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15
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Yu S, Wen Y, Li J, Zhang H, Liu Y. Prenatal Lipopolysaccharide Exposure Promotes Dyslipidemia in the Male Offspring Rats. Front Physiol 2018; 9:542. [PMID: 29867579 PMCID: PMC5964359 DOI: 10.3389/fphys.2018.00542] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 04/26/2018] [Indexed: 12/21/2022] Open
Abstract
Inflammation is critical to the pathogenesis of cardiovascular diseases (CVDs). We have uncovered intrauterine inflammation induced by lipopolysaccharide (LPS) increases CVDs in adult offspring rats. The present study aimed to explore the role of prenatal exposure to LPS on the lipid profiles in male offspring rats and to further assess their susceptibility to high fat diet (HFD). Maternal LPS (0.79 mg/kg) exposure produced a significant increase in serum and hepatic levels of total cholesterol, triglycerides, low-density lipoprotein cholesterol, aspartate amino transferase as well as liver morphological abnormalities in 8-week-old offspring rats. Meanwhile, disturbed gene expressions involved in hepatic lipid metabolism and related signaling pathways were found, especially the up-regulated very-low density lipoprotein receptor (VLDLR) and down-regulated transmembrane 7 superfamily member 2 (TM7SF2). Following HFD treatment, however, the lipid profile shifts and liver dysfunction were exacerbated compared to the offsprings treated with prenatal LPS exposure alone. Compared with that in control offsprings, the hepatic mitochondria (Mt) in offspring rats solely treated with HFD exhibited remarkably higher ATP level, enforced Complex IV expression and a sharp reduction of its activity, whereas the offsprings from LPS-treated dams showed the loss of ATP content, diminished membrane potential, decline in protein expression and activity of mitochondrial respiratory complex IV, increased level of MtDNA deletion as well. Furthermore, treatment with HFD deteriorated these mitochondrial disorders in the prenatally LPS-exposed offspring rats. Taken together, maternal LPS exposure reinforces dyslipidemia in response to a HFD in adult offsprings, which should be associated with mitochondrial abnormalities and disturbed gene expressions of cholesterol metabolism.
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Affiliation(s)
- Shiyun Yu
- Department of Pharmaceutics, College of Pharmacy, Institute of Materia Medica, Third Military Medical University, Chongqing, China
| | - Yan Wen
- Department of Pharmaceutics, College of Pharmacy, Institute of Materia Medica, Third Military Medical University, Chongqing, China.,Department of General Surgery, Southwest Hospital of Third Military Medical University, Chongqing, China
| | - Jingmei Li
- Department of Pharmaceutics, College of Pharmacy, Institute of Materia Medica, Third Military Medical University, Chongqing, China
| | - Haigang Zhang
- Department of Pharmacology, College of Pharmacy, Third Military Medical University, Chongqing, China
| | - Ya Liu
- Department of Pharmaceutics, College of Pharmacy, Institute of Materia Medica, Third Military Medical University, Chongqing, China
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16
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Insulin resistance in obesity: an overview of fundamental alterations. Eat Weight Disord 2018; 23:149-157. [PMID: 29397563 DOI: 10.1007/s40519-018-0481-6] [Citation(s) in RCA: 189] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 01/12/2018] [Indexed: 12/14/2022] Open
Abstract
Obesity is a major health risk factor, and obesity-induced morbidity and complications account for huge costs for affected individuals, families, healthcare systems, and society at large. In particular, obesity is strongly associated with the development of insulin resistance, which in turn plays a key role in the pathogenesis of obesity-associated cardiometabolic complications, including metabolic syndrome components, type 2 diabetes, and cardiovascular diseases. Insulin sensitive tissues, including adipose tissue, skeletal muscle, and liver, are profoundly affected by obesity both at biomolecular and functional levels. Altered adipose organ function may play a fundamental pathogenetic role once fat accumulation has ensued. Modulation of insulin sensitivity appears to be, at least in part, related to changes in redox balance and oxidative stress as well as inflammation, with a relevant underlying role for mitochondrial dysfunction that may exacerbate these alterations. Nutrients and substrates as well as systems involved in host-nutrient interactions, including gut microbiota, have been also identified as modulators of metabolic pathways controlling insulin action. This review aims at providing an overview of these concepts and their potential inter-relationships in the development of insulin resistance, with particular regard to changes in adipose organ and skeletal muscle.
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17
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Garcia J, Decker CW, Sanchez SJ, Ouk JM, Siu KM, Han D. Obesity and steatosis promotes mitochondrial remodeling that enhances respiratory capacity in the liver of ob/ob mice. FEBS Lett 2018; 592:916-927. [DOI: 10.1002/1873-3468.13005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 01/30/2018] [Accepted: 01/31/2018] [Indexed: 01/05/2023]
Affiliation(s)
- Jerome Garcia
- Department of Biology; University of La Verne; CA USA
| | - Carl W. Decker
- Department of Biopharmaceutical Sciences; School of Pharmacy; Keck Graduate Institute; Claremont CA USA
| | | | | | - Krysta M. Siu
- Department of Biology; University of La Verne; CA USA
| | - Derick Han
- Department of Biopharmaceutical Sciences; School of Pharmacy; Keck Graduate Institute; Claremont CA USA
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18
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Abstract
Hepatic steatosis is an underlying feature of nonalcoholic fatty liver disease (NAFLD), which is the most common form of liver disease and is present in up to ∼70% of individuals who are overweight. NAFLD is also associated with hypertriglyceridaemia and low levels of HDL, glucose intolerance, insulin resistance and type 2 diabetes mellitus. Hepatic steatosis is a strong predictor of the development of insulin resistance and often precedes the onset of other known mediators of insulin resistance. This sequence of events suggests that hepatic steatosis has a causal role in the development of insulin resistance in other tissues, such as skeletal muscle. Hepatokines are proteins that are secreted by hepatocytes, and many hepatokines have been linked to the induction of metabolic dysfunction, including fetuin A, fetuin B, retinol-binding protein 4 (RBP4) and selenoprotein P. In this Review, we describe the factors that influence the development of hepatic steatosis, provide evidence of strong links between hepatic steatosis and insulin resistance in non-hepatic tissues, and discuss recent advances in our understanding of how steatosis alters hepatokine secretion to influence metabolic phenotypes through inter-organ communication.
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Affiliation(s)
- Ruth C R Meex
- Monash Biomedicine Discovery Institute, Metabolic Disease and Obesity Program and the Department of Physiology, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
- Department of Human Biology, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, The Netherlands
| | - Matthew J Watt
- Monash Biomedicine Discovery Institute, Metabolic Disease and Obesity Program and the Department of Physiology, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
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Sex-specific associations of low birth weight with adult-onset diabetes and measures of glucose homeostasis: Brazilian Longitudinal Study of Adult Health. Sci Rep 2016; 6:37032. [PMID: 27845438 PMCID: PMC5109479 DOI: 10.1038/srep37032] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 10/24/2016] [Indexed: 11/22/2022] Open
Abstract
Emerging evidence suggests sex differences in the early origins of adult metabolic disease, but this has been little investigated in developing countries. We investigated sex-specific associations between low birth weight (LBW; <2.5 kg) and adult-onset diabetes in 12,525 participants from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). Diabetes was defined by self-reported information and laboratory measurements. In confounder-adjusted analyses, LBW (vs. 2.5–4 kg) was associated with higher prevalence of diabetes in women (Prevalence Ratio (PR) 1.54, 95% CI: 1.32–1.79), not in men (PR 1.06, 95% CI: 0.91–1.25; Pheterogeneity = 0.003). The association was stronger among participants with maternal diabetes (PR 1.60, 95% CI: 1.35–1.91), than those without (PR 1.15, 95% CI: 0.99–1.32; Pheterogeneity = 0.03). When jointly stratified by sex and maternal diabetes, the association was observed for women with (PR 1.77, 95% CI: 1.37–2.29) and without (PR 1.45, 95% CI: 1.20–1.75) maternal diabetes. In contrast, in men, LBW was associated with diabetes in participants with maternal diabetes (PR 1.45, 95% CI: 1.15–1.83), but not in those without (PR 0.92, 95% CI: 0.74–1.14). These sex-specific findings extended to continuous measures of glucose homeostasis. LBW was associated with higher diabetes prevalence in Brazilian women, and in men with maternal diabetes, suggesting sex-specific intrauterine effects on adult metabolic health.
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20
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A possible link between hepatic mitochondrial dysfunction and diet-induced insulin resistance. Eur J Nutr 2016; 55:1-6. [PMID: 26476631 DOI: 10.1007/s00394-015-1073-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 10/08/2015] [Indexed: 12/13/2022]
Abstract
BACKGROUND Mitochondria are the main cellular sites devoted to ATP production and lipid oxidation. Therefore, the mitochondrial dysfunction could be an important determinant of cellular fate of circulating lipids, that accumulate in the cytoplasm, if they are not oxidized. The ectopic fat accumulation is associated with the development of insulin resistance, and a link between mitochondrial dysfunction and insulin resistance has been proposed. METHODS Recent data on the possible link existing between mitochondrial dysfunction in the liver and diet induced obesity will be summarized, focusing on the three factors that affect the mitochondrial oxidation of metabolic fuels, i.e. organelle number, organelle activity, and energetic efficiency of the mitochondrial machinery in synthesizing ATP. Search in PubMed relevant articles from 2003 to 2014 was conducted, by using query “liver mitochondria and obesity” “hepatic mitochondria and obesity” “liver mitochondria and high fat diet” and “hepatic mitochondria and high fat diet” and including related articles by the same groups. RESULTS Several works, by using different physiological approaches, have dealt with alteration in mitochondrial function in obesity and diabetes. Most results show that hepatic mitochondrial function is impaired in models of obesity and insulin resistance induced by high-fat or highfructose feeding. CONCLUSIONS Since mitochondria are the main producers of both cellular energy and free radicals, dysfunctional mitochondria could play an important role in the development of insulin resistance and ectopic fat storage in the liver, thus supporting the emerging idea that mitochondrial dysfunction is closely related to the development of obesity, type 2 diabetes mellitus and non-alcoholic steatohepatitis.
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21
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Scott Chialvo CH, Che R, Reif D, Motsinger-Reif A, Reed LK. Eigenvector metabolite analysis reveals dietary effects on the association among metabolite correlation patterns, gene expression, and phenotypes. Metabolomics 2016; 12:167. [PMID: 28845148 PMCID: PMC5568542 DOI: 10.1007/s11306-016-1117-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 09/06/2016] [Indexed: 01/29/2023]
Abstract
INTRODUCTION 'Multi-omics' datasets obtained from an organism of interest reared under different environmental treatments are increasingly common. Identifying the links among metabolites and transcripts can help to elucidate our understanding of the impact of environment at different levels within the organism. However, many methods for characterizing physiological connections cannot address unidentified metabolites. OBJECTIVES Here, we use Eigenvector Metabolite Analysis (EvMA) to examine links between metabolomic, transcriptomic, and phenotypic variation data and to assess the impact of environmental factors on these associations. Unlike other methods, EvMA can be used to analyze datasets that include unidentified metabolites and unannotated transcripts. METHODS To demonstrate the utility of EvMA, we analyzed metabolomic, transcriptomic, and phenotypic datasets produced from 20 Drosophila melanogaster genotypes reared on four dietary treatments. We used a hierarchical distance-based method to cluster the metabolites. The links between metabolite clusters, gene expression, and overt phenotypes were characterized using the eigenmetabolite (first principal component) of each cluster. RESULTS EvMA recovered chemically related groups of metabolites within the clusters. Using the eigenmetabolite, we identified genes and phenotypes that significantly correlated with each cluster. EvMA identifies new connections between the phenotypes, metabolites, and gene transcripts. Conclusion EvMA provides a simple method to identify correlations between metabolites, gene expression, and phenotypes, which can allow us to partition multivariate datasets into meaningful biological modules and identify under-studied metabolites and unannotated gene transcripts that may be central to important biological processes. This can be used to inform our understanding of the effect of environmental mechanisms underlying physiological states of interest.
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Affiliation(s)
- Clare H Scott Chialvo
- Department of Biological Sciences, University of Alabama, Box 870344, Tuscaloosa, AL 35487, USA
| | - Ronglin Che
- Department of Statistics, North Carolina State University, Raleigh, NC 27695, USA
| | - David Reif
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | | | - Laura K Reed
- Department of Biological Sciences, University of Alabama, Box 870344, Tuscaloosa, AL 35487, USA
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Koliaki C, Szendroedi J, Kaul K, Jelenik T, Nowotny P, Jankowiak F, Herder C, Carstensen M, Krausch M, Knoefel WT, Schlensak M, Roden M. Adaptation of hepatic mitochondrial function in humans with non-alcoholic fatty liver is lost in steatohepatitis. Cell Metab 2015; 21:739-46. [PMID: 25955209 DOI: 10.1016/j.cmet.2015.04.004] [Citation(s) in RCA: 664] [Impact Index Per Article: 73.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 01/29/2015] [Accepted: 03/31/2015] [Indexed: 02/07/2023]
Abstract
The association of hepatic mitochondrial function with insulin resistance and non-alcoholic fatty liver (NAFL) or steatohepatitis (NASH) remains unclear. This study applied high-resolution respirometry to directly quantify mitochondrial respiration in liver biopsies of obese insulin-resistant humans without (n = 18) or with (n = 16) histologically proven NAFL or with NASH (n = 7) compared to lean individuals (n = 12). Despite similar mitochondrial content, obese humans with or without NAFL had 4.3- to 5.0-fold higher maximal respiration rates in isolated mitochondria than lean persons. NASH patients featured higher mitochondrial mass, but 31%-40% lower maximal respiration, which associated with greater hepatic insulin resistance, mitochondrial uncoupling, and leaking activity. In NASH, augmented hepatic oxidative stress (H2O2, lipid peroxides) and oxidative DNA damage (8-OH-deoxyguanosine) was paralleled by reduced anti-oxidant defense capacity and increased inflammatory response. These data suggest adaptation of the liver ("hepatic mitochondrial flexibility") at early stages of obesity-related insulin resistance, which is subsequently lost in NASH.
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Affiliation(s)
- Chrysi Koliaki
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, 40225, Düsseldorf, Germany; German Center for Diabetes Research (DZD e.V.), 40225, Düsseldorf, Germany; Department of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University, 40225, Düsseldorf, Germany
| | - Julia Szendroedi
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, 40225, Düsseldorf, Germany; German Center for Diabetes Research (DZD e.V.), 40225, Düsseldorf, Germany; Department of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University, 40225, Düsseldorf, Germany
| | - Kirti Kaul
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, 40225, Düsseldorf, Germany; German Center for Diabetes Research (DZD e.V.), 40225, Düsseldorf, Germany
| | - Tomas Jelenik
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, 40225, Düsseldorf, Germany; German Center for Diabetes Research (DZD e.V.), 40225, Düsseldorf, Germany
| | - Peter Nowotny
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, 40225, Düsseldorf, Germany; German Center for Diabetes Research (DZD e.V.), 40225, Düsseldorf, Germany
| | - Frank Jankowiak
- Institute of Pathology, Heinrich Heine University, 40225, Düsseldorf, Germany
| | - Christian Herder
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, 40225, Düsseldorf, Germany; German Center for Diabetes Research (DZD e.V.), 40225, Düsseldorf, Germany
| | - Maren Carstensen
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, 40225, Düsseldorf, Germany; German Center for Diabetes Research (DZD e.V.), 40225, Düsseldorf, Germany
| | - Markus Krausch
- Department of General, Visceral and Pediatric Surgery, Heinrich Heine University, 40225, Düsseldorf, Germany
| | - Wolfram Trudo Knoefel
- Department of General, Visceral and Pediatric Surgery, Heinrich Heine University, 40225, Düsseldorf, Germany
| | - Matthias Schlensak
- General Surgery Department, St. Martinus Hospital, 40219, Düsseldorf, Germany
| | - Michael Roden
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, 40225, Düsseldorf, Germany; German Center for Diabetes Research (DZD e.V.), 40225, Düsseldorf, Germany; Department of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University, 40225, Düsseldorf, Germany.
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Zhang D, Lu K, Dong Z, Jiang G, Xu W, Liu W. The effect of exposure to a high-fat diet on microRNA expression in the liver of blunt snout bream (Megalobrama amblycephala). PLoS One 2014; 9:e96132. [PMID: 24788396 PMCID: PMC4008502 DOI: 10.1371/journal.pone.0096132] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2014] [Accepted: 04/02/2014] [Indexed: 12/15/2022] Open
Abstract
Blunt snout bream (Megalobrama amblycephala) are susceptible to hepatic steatosis when maintained in modern intensive culture systems. The aim of this study was to investigate the potential roles of microRNAs (miRNAs) in diet-induced hepatic steatosis in this species. MiRNAs, small non-coding RNAs that regulate gene expression at the posttranscriptional level, are involved in diverse biological processes, including lipid metabolism. Deep sequencing of hepatic small RNA libraries from blunt snout bream fed normal-fat and high-fat diets identified 202 (193 known and 9 novel) miRNAs, of which 12 were differentially expressed between the normal-fat and high-fat diet groups. Quantitative stem-loop reverse transcriptase-polymerase chain reaction analyses confirmed the upregulation of miR-30c and miR-30e-3p and the downregulation of miR-145 and miR-15a-5p in high-fat diet-fed fish. Bioinformatics tools were used to predict the targets of these verified miRNAs and to explore potential downstream gene ontology biological process categories and Kyoto Encyclopedia of Genes and Genomes pathways. Six putative lipid metabolism-related target genes (fetuin-B, Cyp7a1, NADH dehydrogenase (ubiquinone) 1 beta subcomplex subunit 2, 3-oxoacid CoA transferase 1b, stearoyl-CoA desaturase, and fatty-acid synthase) were identified as having potential important roles in the development of diet-induced hepatic steatosis in blunt snout bream. The results presented here are a foundation for future studies of miRNA-controlled lipid metabolism regulatory networks in blunt snout bream.
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Affiliation(s)
- Dingdong Zhang
- Key Laboratory of Aquatic Nutrition and Feed Science of Jiangsu Province, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, China
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, China
| | - Kangle Lu
- Key Laboratory of Aquatic Nutrition and Feed Science of Jiangsu Province, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Zaijie Dong
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, China
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, China
- * E-mail: (WL); (ZD)
| | - Guangzhen Jiang
- Key Laboratory of Aquatic Nutrition and Feed Science of Jiangsu Province, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Weina Xu
- Key Laboratory of Aquatic Nutrition and Feed Science of Jiangsu Province, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Wenbin Liu
- Key Laboratory of Aquatic Nutrition and Feed Science of Jiangsu Province, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
- * E-mail: (WL); (ZD)
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24
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Barazzoni R, Semolic A, Cattin MR, Zanetti M, Guarnieri G. Acylated ghrelin limits fat accumulation and improves redox state and inflammation markers in the liver of high-fat-fed rats. Obesity (Silver Spring) 2014; 22:170-7. [PMID: 23512916 DOI: 10.1002/oby.20454] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 02/28/2013] [Accepted: 02/28/2013] [Indexed: 12/30/2022]
Abstract
OBJECTIVE Obesity commonly causes hepatic lipid accumulation that may favor oxidative stress and inflammation with negative clinical impact. Acylated ghrelin (A-Ghr) modulates body lipid distribution and metabolism, and it may exert antioxidant effects in vitro as well as systemic anti-inflammatory effects in vivo. The impact of A-Ghr on liver triglyceride content, redox state and inflammation markers in diet-induced obesity was investigated. DESIGN AND METHODS A-Ghr (200-μg/injection: HFG) or saline (HF) were administered subcutaneously twice-daily for 4 days to 12-week-old male rats fed a high-fat diet for 1 month (n = 8-10/group). RESULTS Compared to lean animals, liver triglyceride accumulation occurred in HF despite enhanced phosphorylation of the lipid oxidation regulator AMPK and preserved mitochondrial enzyme activities. High triglycerides were accompanied by pro-oxidant changes in redox state and proinflammatory changes in NF-kB and TNF-alpha. A-Ghr limited liver triglyceride excess (P < 0.05 HF > HFG > Control) with concomitant activation of glutathione peroxidase and normalized redox state and cytokines. A-Ghr-induced liver changes were associated with higher plasma adiponectin and lower circulating fatty acids (P < 0.05 HFG vs. HF) CONCLUSIONS A-Ghr limits liver triglyceride accumulation and normalizes tissue redox state and inflammation markers in diet-induced obese rats. These results suggest a favorable impact of A-Ghr on hepatic complications of diet-induced obesity.
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Affiliation(s)
- Rocco Barazzoni
- Clinica Medica, Department of Medical, Surgical and Health Sciences, University of Trieste, Italy
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25
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Genetic dissection of quantitative trait Loci for hemostasis and thrombosis on mouse chromosomes 11 and 5 using congenic and subcongenic strains. PLoS One 2013; 8:e77539. [PMID: 24147020 PMCID: PMC3798288 DOI: 10.1371/journal.pone.0077539] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 09/06/2013] [Indexed: 12/25/2022] Open
Abstract
Susceptibility to thrombosis varies in human populations as well as many inbred mouse strains. Only a small portion of this variation has been identified, suggesting that there are unknown modifier genes. The objective of this study was to narrow the quantitative trait locus (QTL) intervals previously identified for hemostasis and thrombosis on mouse distal chromosome 11 (Hmtb6) and on chromosome 5 (Hmtb4 and Hmtb5). In a tail bleeding/rebleeding assay, a reporter assay for hemostasis and thrombosis, subcongenic strain (6A-2) had longer clot stability time than did C57BL/6J (B6) mice but a similar time to the B6-Chr11A/J consomic mice, confirming the Hmtb6 phenotype. Six congenic and subcongenic strains were constructed for chromosome 5, and the congenic strain, 2A-1, containing the shortest A/J interval (16.6 cM, 26.6 Mbp) in the Hmtb4 region, had prolonged clot stability time compared to B6 mice. In the 3A-2 and CSS-5 mice bleeding time was shorter than for B6, mice confirming the Hmtb5 QTL. An increase in bleeding time was identified in another congenic strain (3A-1) with A/J interval (24.8 cM, 32.9 Mbp) in the proximal region of chromosome 5, confirming a QTL for bleeding previously mapped to that region and designated as Hmtb10. The subcongenic strain 4A-2 with the A/J fragment in the proximal region had a long occlusion time of the carotid artery after ferric chloride injury and reduced dilation after injury to the abdominal aorta compared to B6 mice, suggesting an additional locus in the proximal region, which was designated Hmtb11 (5 cM, 21.4 Mbp). CSS-17 mice crossed with congenic strains, 3A-1 and 3A-2, modified tail bleeding. Using congenic and subcongenic analysis, candidate genes previously identified and novel genes were identified as modifiers of hemostasis and thrombosis in each of the loci Hmtb6, Hmtb4, Hmtb10, and Hmtb11.
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26
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Guo Y, Darshi M, Ma Y, Perkins GA, Shen Z, Haushalter KJ, Saito R, Chen A, Lee YS, Patel HH, Briggs SP, Ellisman MH, Olefsky JM, Taylor SS. Quantitative proteomic and functional analysis of liver mitochondria from high fat diet (HFD) diabetic mice. Mol Cell Proteomics 2013; 12:3744-58. [PMID: 24030101 DOI: 10.1074/mcp.m113.027441] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Insulin resistance plays a major role in the development of type 2 diabetes and obesity and affects a number of biological processes such as mitochondrial biogenesis. Though mitochondrial dysfunction has been linked to the development of insulin resistance and pathogenesis of type 2 diabetes, the precise mechanism linking the two is not well understood. We used high fat diet (HFD)-induced obesity dependent diabetes mouse models to gain insight into the potential pathways altered with metabolic disease, and carried out quantitative proteomic analysis of liver mitochondria. As previously reported, proteins involved in fatty acid oxidation, branched chain amino acid degradation, tricarboxylic acid cycle, and oxidative phosphorylation were uniformly up-regulated in the liver of HFD fed mice compared with that of normal diet. Further, our studies revealed that retinol metabolism is distinctly down-regulated and the mitochondrial structural proteins-components of mitochondrial inter-membrane space bridging (MIB) complex (Mitofilin, Sam50, and ChChd3), and Tim proteins-essential for protein import, are significantly up-regulated in HFD fed mice. Structural and functional studies on HFD and normal diet liver mitochondria revealed remodeling of HFD mitochondria to a more condensed form with increased respiratory capacity and higher ATP levels compared with normal diet mitochondria. Thus, it is likely that the structural remodeling is essential to accommodate the increased protein content in presence of HFD: the mechanism could be through the MIB complex promoting contact site and crista junction formation and in turn facilitating the lipid and protein uptake.
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27
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Still AJ, Floyd BJ, Hebert AS, Bingman CA, Carson JJ, Gunderson DR, Dolan BK, Grimsrud PA, Dittenhafer-Reed KE, Stapleton DS, Keller MP, Westphall MS, Denu JM, Attie AD, Coon JJ, Pagliarini DJ. Quantification of mitochondrial acetylation dynamics highlights prominent sites of metabolic regulation. J Biol Chem 2013; 288:26209-26219. [PMID: 23864654 DOI: 10.1074/jbc.m113.483396] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Lysine acetylation is rapidly becoming established as a key post-translational modification for regulating mitochondrial metabolism. Nonetheless, distinguishing regulatory sites from among the thousands identified by mass spectrometry and elucidating how these modifications alter enzyme function remain primary challenges. Here, we performed multiplexed quantitative mass spectrometry to measure changes in the mouse liver mitochondrial acetylproteome in response to acute and chronic alterations in nutritional status, and integrated these data sets with our compendium of predicted Sirt3 targets. These analyses highlight a subset of mitochondrial proteins with dynamic acetylation sites, including acetyl-CoA acetyltransferase 1 (Acat1), an enzyme central to multiple metabolic pathways. We performed in vitro biochemistry and molecular modeling to demonstrate that acetylation of Acat1 decreases its activity by disrupting the binding of coenzyme A. Collectively, our data reveal an important new target of regulatory acetylation and provide a foundation for investigating the role of select mitochondrial protein acetylation sites in mediating acute and chronic metabolic transitions.
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Affiliation(s)
| | | | - Alexander S Hebert
- Chemistry, and; Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | | | | | | | | | | | | | | | | | - Michael S Westphall
- Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | | | | | - Joshua J Coon
- Chemistry, and; Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, Wisconsin 53706; Biomolecular Chemistry and
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28
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Jia Y, Li R, Cong R, Yang X, Sun Q, Parvizi N, Zhao R. Maternal low-protein diet affects epigenetic regulation of hepatic mitochondrial DNA transcription in a sex-specific manner in newborn piglets associated with GR binding to its promoter. PLoS One 2013; 8:e63855. [PMID: 23691106 PMCID: PMC3653849 DOI: 10.1371/journal.pone.0063855] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Accepted: 04/08/2013] [Indexed: 11/20/2022] Open
Abstract
Mitochondrial oxidative phosphorylation (OXPHOS) plays an important role in energy homeostasis by controlling electron transfer and ATP generation. Maternal malnutrition during pregnancy affects mitochondrial (mt) DNA-encoded OXPHOS activity in offspring, yet it is unknown whether epigenetic mechanism is involved in the transcriptional regulation of mtDNA-encoded OXPHOS genes. In this study, 14 primiparous purebred Meishan sows were fed either standard- (SP, 12% crude protein) or low-protein (LP; 6% crude protein) diets throughout gestation, and the hepatic expression and transcriptional regulation of mtDNA-encoded OXPHOS genes were analyzed in newborn piglets. Maternal low protein diet decreased hepatic mtDNA copy number in males, but not in females. LP male piglets had significantly higher hepatic AMP concentration and low energy charge, which was accompanied by enhanced mRNA expression of NADH dehydrogenase subunits 6, cytochrome c oxidase subunit 1, 2, 3 and cytochrome b, as well as increased cytochrome c oxidase enzyme activity. In contrast, LP female piglets showed significantly lower hepatic AMP concentrations and higher energy charge with no alterations in OXPHOS gene expression. Moreover, LP males demonstrated higher glucocorticoid receptor (GR) binding to the mtDNA promoter compared with SP males, which was accompanied by lower cytosine methylation and hydroxymethylation on mtDNA promoter. Interestingly, opposite changes were seen in females, which showed diminished GR binding and enriched cytosine methylation and hydroxymethylation on mtDNA promoter. These results suggest that maternal low protein diet during pregnancy causes sex-dependent epigenetic alterations in mtDNA-encoded OXPHOS gene expression, possibly GR is involved in mtDNA transcription regulation.
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Affiliation(s)
- Yimin Jia
- Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Runsheng Li
- Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Rihua Cong
- Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, Jiangsu, China
- College of Veterinary Medicine, Northwest A & F University, Yangling, Shannxi, China
| | - Xiaojing Yang
- Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Qinwei Sun
- Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Nahid Parvizi
- Department of Functional Genomics and Bioregulation, Institute of Animal Genetics, FLI, Mariensee, Neustadt, Germany
| | - Ruqian Zhao
- Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, Jiangsu, China
- * E-mail:
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29
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Meng R, Zhu D, Bi Y, Yang D, Wang Y. Erythropoietin inhibits gluconeogenesis and inflammation in the liver and improves glucose intolerance in high-fat diet-fed mice. PLoS One 2013; 8:e53557. [PMID: 23326455 PMCID: PMC3542353 DOI: 10.1371/journal.pone.0053557] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 11/29/2012] [Indexed: 12/19/2022] Open
Abstract
Erythropoietin (EPO) has multiple biological functions, including the modulation of glucose metabolism. However, the mechanisms underlying the action of EPO are still obscure. This study is aimed at investigating the potential mechanisms by which EPO improves glucose tolerance in an animal model of type 2 diabetes. Male C57BL/6 mice were fed with high-fat diet (HFD) for 12 weeks and then treated with EPO (HFD-EPO) or vehicle saline (HFD-Con) for two week. The levels of fasting blood glucose, serum insulin and glucose tolerance were measured and the relative levels of insulin-related phosphatidylinositol 3-kinase (PI3K)/Akt, insulin receptor (IR) and IR substrate 1 (IRS1) phosphorylation were determined. The levels of phosphoenolpyruvate carboxykinase (PEPCK), glucose-6- phosphatase (G6Pase), toll like receptor 4 (TLR4), tumor necrosis factor (TNF)-α and IL-6 expression and nuclear factor-κB (NF-κB) and c-Jun N-terminal kinase (JNK), extracellular-signal-regulated kinase (ERK) and p38 MAPK activation in the liver were examined. EPO treatment significantly reduced the body weights and the levels of fasting blood glucose and serum insulin and improved the HFD-induced glucose intolerance in mice. EPO treatment significantly enhanced the levels of Akt, but not IR and IRS1, phosphorylation, accompanied by inhibiting the PEPCK and G6Pase expression in the liver. Furthermore, EPO treatment mitigated the HFD-induced inflammatory TNF-α and IL-6 production, TLR4 expression, NF-κB and JNK, but not ERK and p38 MAPK, phosphorylation in the liver. Therefore, our data indicated that EPO treatment improved glucose intolerance by inhibiting gluconeogenesis and inflammation in the livers of HFD-fed mice.
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Affiliation(s)
- Ran Meng
- Department of Endocrinology, Nanjing Drum Tower Hospital, Nanjing University School of Medicine, Nanjing, China
- Department of Medical Genetics, Nanjing University School of Medicine, Nanjing, China
- Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, China
| | - Dalong Zhu
- Department of Endocrinology, Nanjing Drum Tower Hospital, Nanjing University School of Medicine, Nanjing, China
- * E-mail: (DLZ); (YPW)
| | - Yan Bi
- Department of Endocrinology, Nanjing Drum Tower Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Donghui Yang
- Department of Endocrinology, Nanjing Drum Tower Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Yaping Wang
- Department of Medical Genetics, Nanjing University School of Medicine, Nanjing, China
- Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, China
- * E-mail: (DLZ); (YPW)
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30
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Lee S, Kwon MS, Park T. Network graph analysis of gene-gene interactions in genome-wide association study data. Genomics Inform 2012; 10:256-62. [PMID: 23346039 PMCID: PMC3543927 DOI: 10.5808/gi.2012.10.4.256] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 11/14/2012] [Accepted: 11/16/2012] [Indexed: 12/18/2022] Open
Abstract
Most common complex traits, such as obesity, hypertension, diabetes, and cancers, are known to be associated with multiple genes, environmental factors, and their epistasis. Recently, the development of advanced genotyping technologies has allowed us to perform genome-wide association studies (GWASs). For detecting the effects of multiple genes on complex traits, many approaches have been proposed for GWASs. Multifactor dimensionality reduction (MDR) is one of the powerful and efficient methods for detecting high-order gene-gene (GxG) interactions. However, the biological interpretation of GxG interactions identified by MDR analysis is not easy. In order to aid the interpretation of MDR results, we propose a network graph analysis to elucidate the meaning of identified GxG interactions. The proposed network graph analysis consists of three steps. The first step is for performing GxG interaction analysis using MDR analysis. The second step is to draw the network graph using the MDR result. The third step is to provide biological evidence of the identified GxG interaction using external biological databases. The proposed method was applied to Korean Association Resource (KARE) data, containing 8838 individuals with 327,632 single-nucleotide polymorphisms, in order to perform GxG interaction analysis of body mass index (BMI). Our network graph analysis successfully showed that many identified GxG interactions have known biological evidence related to BMI. We expect that our network graph analysis will be helpful to interpret the biological meaning of GxG interactions.
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Affiliation(s)
- Sungyoung Lee
- Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul 151-747, Korea
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31
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Midha MK, Tikoo K, Sinha N, Kaur S, Verma HN, Rao KVS, Chatterjee S, Manivel V. Extracting Time-dependent Obese-diabetic Specific Networks in Hepatic Proteome Analysis. J Proteome Res 2012; 11:6030-43. [DOI: 10.1021/pr300711a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Mukul K. Midha
- Immunology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067,
India
- School of Life Sciences, Jaipur National University, Jaipur 302025, India
| | - Kamiya Tikoo
- Immunology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067,
India
| | - Neeraj Sinha
- Immunology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067,
India
| | - Simarjeet Kaur
- Immunology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067,
India
| | - Hirdya N. Verma
- School of Life Sciences, Jaipur National University, Jaipur 302025, India
| | - Kanury V. S. Rao
- Immunology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067,
India
| | - Samrat Chatterjee
- Immunology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067,
India
| | - Venkatasamy Manivel
- Immunology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067,
India
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32
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Grimsrud PA, Carson JJ, Hebert AS, Hubler SL, Niemi NM, Bailey DJ, Jochem A, Stapleton DS, Keller MP, Westphall MS, Yandell BS, Attie AD, Coon JJ, Pagliarini DJ. A quantitative map of the liver mitochondrial phosphoproteome reveals posttranslational control of ketogenesis. Cell Metab 2012; 16:672-83. [PMID: 23140645 PMCID: PMC3506251 DOI: 10.1016/j.cmet.2012.10.004] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 09/25/2012] [Accepted: 10/12/2012] [Indexed: 10/27/2022]
Abstract
Mitochondria are dynamic organelles that play a central role in a diverse array of metabolic processes. Elucidating mitochondrial adaptations to changing metabolic demands and the pathogenic alterations that underlie metabolic disorders represent principal challenges in cell biology. Here, we performed multiplexed quantitative mass spectrometry-based proteomics to chart the remodeling of the mouse liver mitochondrial proteome and phosphoproteome during both acute and chronic physiological transformations in more than 50 mice. Our analyses reveal that reversible phosphorylation is widespread in mitochondria, and is a key mechanism for regulating ketogenesis during the onset of obesity and type 2 diabetes. Specifically, we have demonstrated that phosphorylation of a conserved serine on Hmgcs2 (S456) significantly enhances its catalytic activity in response to increased ketogenic demand. Collectively, our work describes the plasticity of this organelle at high resolution and provides a framework for investigating the roles of proteome restructuring and reversible phosphorylation in mitochondrial adaptation.
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Affiliation(s)
- Paul A Grimsrud
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
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Edible dry bean consumption (Phaseolus vulgaris L.) modulates cardiovascular risk factors and diet-induced obesity in rats and mice. Br J Nutr 2012; 108 Suppl 1:S66-73. [DOI: 10.1017/s0007114512000839] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Pulses are grain legumes that have sustained the civilisations of the world throughout their development; yet this staple food crop has fallen into disuse, particularly in Westernised societies, and decreased consumption parallels increased prevalence of CVD. The objective of the present study was to identify mechanisms that account for the cardioprotective activity of dry bean (Phaseolus vulgaris L.), one of the four primary pulse crops, which is widely produced and consumed globally. Laboratory assays that can be used for in vivo screening of dry beans and other pulses to identify those with the greatest potential to benefit human health are also reported. Sprague–Dawley rats and a diet-induced obesity model in C57Bl/6 mice were used to assess the effect of cooked dry bean incorporated into a purified diet formulation on plasma lipids and hepatic proteins involved in the regulation of lipid biosynthesis. In both animal species, short-term feeding of a bean-containing diet reduced plasma total cholesterol and LDL-cholesterol without affecting HDL-cholesterol or total TAG. Mechanisms associated with cholesterol catabolism and excretion are the likely targets of the bean effect. Unexpectedly, bean-fed obese mice experienced weight loss as well as an improved plasma lipid profile within a 12 d time frame. These findings support the use of short-term (7–14 d) assays to investigate mechanisms that account for the cardioprotective and weight regulatory effects of dry bean and to screen dry bean germplasm resources for types of bean with high protective activity. These same assays can be used to identify the bioactive components of bean that account for the observed effects.
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Satapati S, Sunny NE, Kucejova B, Fu X, He TT, Méndez-Lucas A, Shelton JM, Perales JC, Browning JD, Burgess SC. Elevated TCA cycle function in the pathology of diet-induced hepatic insulin resistance and fatty liver. J Lipid Res 2012; 53:1080-92. [PMID: 22493093 PMCID: PMC3351815 DOI: 10.1194/jlr.m023382] [Citation(s) in RCA: 292] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 03/29/2012] [Indexed: 12/26/2022] Open
Abstract
The manner in which insulin resistance impinges on hepatic mitochondrial function is complex. Although liver insulin resistance is associated with respiratory dysfunction, the effect on fat oxidation remains controversial, and biosynthetic pathways that traverse mitochondria are actually increased. The tricarboxylic acid (TCA) cycle is the site of terminal fat oxidation, chief source of electrons for respiration, and a metabolic progenitor of gluconeogenesis. Therefore, we tested whether insulin resistance promotes hepatic TCA cycle flux in mice progressing to insulin resistance and fatty liver on a high-fat diet (HFD) for 32 weeks using standard biomolecular and in vivo (2)H/(13)C tracer methods. Relative mitochondrial content increased, but respiratory efficiency declined by 32 weeks of HFD. Fasting ketogenesis became unresponsive to feeding or insulin clamp, indicating blunted but constitutively active mitochondrial β-oxidation. Impaired insulin signaling was marked by elevated in vivo gluconeogenesis and anaplerotic and oxidative TCA cycle flux. The induction of TCA cycle function corresponded to the development of mitochondrial respiratory dysfunction, hepatic oxidative stress, and inflammation. Thus, the hepatic TCA cycle appears to enable mitochondrial dysfunction during insulin resistance by increasing electron deposition into an inefficient respiratory chain prone to reactive oxygen species production and by providing mitochondria-derived substrate for elevated gluconeogenesis.
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Affiliation(s)
- Santhosh Satapati
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
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Mittendorfer B. Origins of metabolic complications in obesity: adipose tissue and free fatty acid trafficking. Curr Opin Clin Nutr Metab Care 2011; 14:535-41. [PMID: 21849896 PMCID: PMC3711689 DOI: 10.1097/mco.0b013e32834ad8b6] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE OF REVIEW Obesity is associated with a number of serious medical complications that are risk factors for cardiovascular disease (e.g., insulin resistance, dyslipidemia, and liver fat accumulation). Alterations in fatty acid trafficking, both between tissues and within cells, represent a key feature in the pathophysiology of the metabolic complications in obese patients. The ways by which fatty acid 're-routing' may affect metabolic function are summarized in this article. RECENT FINDINGS Ectopic fat accumulation (i.e., fat accumulation in nonadipose tissues) appears to be a key feature distinguishing metabolically healthy from metabolically abnormal patients. This observation has led to the belief that an imbalance in fatty acid trafficking away from adipose tissue toward nonadipose tissues is a primary cause for the development of metabolic alterations in obese patients. More recently, however, it has become apparent that fatty acid trafficking within nonadipose tissues cells (i.e., toward storage - in the form of triglycerides - and oxidation) may be equally important in determining a person's risk for development of metabolic disease. SUMMARY The pathophysiology of the metabolic alterations associated with obesity is probably multifactorial within a complex network of coordinated physiological responses. Only through the integration of multiple concepts, will it be possible to further our understanding in this area and to help prevent the metabolic alterations associated with obesity.
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Affiliation(s)
- Bettina Mittendorfer
- Division of Geriatrics and Nutritional Sciences, Washington University School of Medicine, St. Louis, Missouri, USA.
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Yazbek SN, Buchner DA, Geisinger JM, Burrage LC, Spiezio SH, Zentner GE, Hsieh CW, Scacheri PC, Croniger CM, Nadeau JH. Deep congenic analysis identifies many strong, context-dependent QTLs, one of which, Slc35b4, regulates obesity and glucose homeostasis. Genome Res 2011; 21:1065-73. [PMID: 21507882 DOI: 10.1101/gr.120741.111] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Although central to many studies of phenotypic variation and disease susceptibility, characterizing the genetic architecture of complex traits has been unexpectedly difficult. For example, most of the susceptibility genes that contribute to highly heritable conditions such as obesity and type 2 diabetes (T2D) remain to be identified despite intensive study. We took advantage of mouse models of diet-induced metabolic disease in chromosome substitution strains (CSSs) both to characterize the genetic architecture of diet-induced obesity and glucose homeostasis and to test the feasibility of gene discovery. Beginning with a survey of CSSs, followed with genetic and phenotypic analysis of congenic, subcongenic, and subsubcongenic strains, we identified a remarkable number of closely linked, phenotypically heterogeneous quantitative trait loci (QTLs) on mouse chromosome 6 that have unexpectedly large phenotypic effects. Although fine-mapping reduced the genomic intervals and gene content of these QTLs over 3000-fold, the average phenotypic effect on body weight was reduced less than threefold, highlighting the "fractal" nature of genetic architecture in mice. Despite this genetic complexity, we found evidence for 14 QTLs in only 32 recombination events in less than 3000 mice, and with an average of four genes located within the three body weight QTLs in the subsubcongenic strains. For Obrq2a1, genetic and functional studies collectively identified the solute receptor Slc35b4 as a regulator of obesity, insulin resistance, and gluconeogenesis. This work demonstrated the unique power of CSSs as a platform for studying complex genetic traits and identifying QTLs.
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Affiliation(s)
- Soha N Yazbek
- Department of Genetics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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