201
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Moran B, Cummins SB, Creevey CJ, Butler ST. Transcriptomics of liver and muscle in Holstein cows genetically divergent for fertility highlight differences in nutrient partitioning and inflammation processes. BMC Genomics 2016; 17:603. [PMID: 27514375 PMCID: PMC4982134 DOI: 10.1186/s12864-016-2938-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 07/14/2016] [Indexed: 01/01/2023] Open
Abstract
Background The transition between pregnancy and lactation is a major physiological change for dairy cows. Complex systemic and local processes involving regulation of energy balance, galactopoiesis, utilisation of body reserves, insulin resistance, resumption of oestrous cyclicity and involution of the uterus can affect animal productivity and hence farm profitability. Here we used an established Holstein dairy cow model of fertility that displayed genetic and phenotypic divergence in calving interval. Cows had similar genetic merit for milk production traits, but either very good genetic merit for fertility traits (‘Fert+’; n = 8) or very poor genetic merit for fertility traits (‘Fert-’; n = 8). We used RNA sequencing to investigate gene expression profiles in both liver and muscle tissue biopsies at three distinct time-points: late pregnancy, early lactation and mid lactation (-18, 1 and 147 days relative to parturition, respectively). Results We found 807 and 815 unique genes to be differentially expressed in at least one time-point in liver and muscle respectively, of which 79 % and 83 % were only found in a single time-point; 40 and 41 genes were found differentially expressed at every time-point indicating possible systemic or chronic dysregulation. Functional annotation of all differentially expressed genes highlighted two physiological processes that were impacted at every time-point in the study, These were immune and inflammation, and metabolic, lipid and carbohydrate-binding. Conclusion These pathways have previously been identified by other researchers. We show that several specific genes which are differentially regulated, including IGF-1, might impact dairy fertility. We postulate that an increased burden of reactive oxidation species, coupled with a chronic inflammatory state, might reduce dairy cow fertility in our model. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2938-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bruce Moran
- Teagasc, Animal & Grassland Research and Innovation Centre, Grange, Dunsany, Co. Meath, Ireland.,UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Sean B Cummins
- Teagasc, Animal & Grassland Research and Innovation Centre, Moorepark, Fermoy, Co. Cork, Ireland
| | - Christopher J Creevey
- Teagasc, Animal & Grassland Research and Innovation Centre, Grange, Dunsany, Co. Meath, Ireland.,Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, SY23 3FG, UK
| | - Stephen T Butler
- Teagasc, Animal & Grassland Research and Innovation Centre, Moorepark, Fermoy, Co. Cork, Ireland.
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202
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Yao D, Luo J, He Q, Shi H, Li J, Wang H, Xu H, Chen Z, Yi Y, Loor JJ. SCD1 Alters Long-Chain Fatty Acid (LCFA) Composition and Its Expression Is Directly Regulated by SREBP-1 and PPARγ 1 in Dairy Goat Mammary Cells. J Cell Physiol 2016; 232:635-649. [DOI: 10.1002/jcp.25469] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Accepted: 06/23/2016] [Indexed: 12/14/2022]
Affiliation(s)
- Dawei Yao
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology; Northwest A&F University; Yangling Shaanxi P. R. China
| | - Jun Luo
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology; Northwest A&F University; Yangling Shaanxi P. R. China
| | - Qiuya He
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology; Northwest A&F University; Yangling Shaanxi P. R. China
| | - Hengbo Shi
- College of Life Sciences; Zhejiang Sci-Tech University; Hangzhou P. R. China
| | - Jun Li
- College of Animal Science and Technology; Henan University of Animal Husbandry and Economy; Zhengzhou Henan P. R. China
| | - Hui Wang
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology; Northwest A&F University; Yangling Shaanxi P. R. China
| | - Huifen Xu
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology; Northwest A&F University; Yangling Shaanxi P. R. China
| | - Zhi Chen
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology; Northwest A&F University; Yangling Shaanxi P. R. China
| | - Yongqing Yi
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology; Northwest A&F University; Yangling Shaanxi P. R. China
| | - Juan J. Loor
- Mammalian NutriPhysioGenomics, Department of Animal Sciences and Division of Nutritional Sciences; University of IIlinois; Urbana Illinois
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203
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Karahashi M, Hirata-Hanta Y, Kawabata K, Tsutsumi D, Kametani M, Takamatsu N, Sakamoto T, Yamazaki T, Asano S, Mitsumoto A, Kawashima Y, Kudo N. Abnormalities in the Metabolism of Fatty Acids and Triacylglycerols in the Liver of the Goto-Kakizaki Rat: A Model for Non-Obese Type 2 Diabetes. Lipids 2016; 51:955-71. [PMID: 27372943 DOI: 10.1007/s11745-016-4171-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 06/20/2016] [Indexed: 02/08/2023]
Abstract
The Goto-Kakizaki (GK) rat is widely used as an animal model for spontaneous-onset type 2 diabetes without obesity; nevertheless, little information is available on the metabolism of fatty acids and triacylglycerols (TAG) in their livers. We investigated the mechanisms underlying the alterations in the metabolism of fatty acids and TAG in their livers, in comparison with Zucker (fa/fa) rats, which are obese and insulin resistant. Lipid profiles, the expression of genes for enzymes and proteins related to the metabolism of fatty acid and TAG, de novo synthesis of fatty acids and TAG in vivo, fatty acid synthase activity in vitro, fatty acid oxidation in liver slices, and very-low-density-lipoprotein (VLDL)-TAG secretion in vivo were estimated. Our results revealed that (1) the TAG accumulation was moderate, (2) the de novo fatty acid synthesis was increased by upregulation of fatty acid synthase in a post-transcriptional manner, (3) fatty acid oxidation was also augmented through the induction of carnitine palmitoyltransferase 1a, and (4) the secretion rate of VLDL-TAG remained unchanged in the livers of GK rats. These results suggest that, despite the fact that GK rats exhibit non-obese type 2 diabetes, the upregulation of de novo lipogenesis is largely compensated by the upregulation of fatty acid oxidation, resulting in only moderate increase in TAG accumulation in the liver.
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Affiliation(s)
- Minako Karahashi
- School of Pharmaceutical Sciences, Josai University, 1-1 Keyakidai, Sakado, Saitama, 350-0295, Japan
| | - Yuko Hirata-Hanta
- School of Pharmaceutical Sciences, Josai University, 1-1 Keyakidai, Sakado, Saitama, 350-0295, Japan
| | - Kohei Kawabata
- School of Pharmaceutical Sciences, Josai University, 1-1 Keyakidai, Sakado, Saitama, 350-0295, Japan
| | - Daisuke Tsutsumi
- School of Pharmaceutical Sciences, Josai University, 1-1 Keyakidai, Sakado, Saitama, 350-0295, Japan
| | - Misaki Kametani
- School of Pharmaceutical Sciences, Josai University, 1-1 Keyakidai, Sakado, Saitama, 350-0295, Japan
| | - Nanako Takamatsu
- School of Pharmaceutical Sciences, Josai University, 1-1 Keyakidai, Sakado, Saitama, 350-0295, Japan
| | - Takeshi Sakamoto
- School of Pharmaceutical Sciences, Josai University, 1-1 Keyakidai, Sakado, Saitama, 350-0295, Japan
| | - Tohru Yamazaki
- School of Pharmaceutical Sciences, Josai University, 1-1 Keyakidai, Sakado, Saitama, 350-0295, Japan
| | - Satoshi Asano
- Department of Pharmaceutical Sciences, International University of Health and Welfare, 2600-1 Kitakanemaru, Ohtawara, Tochigi, 324-8501, Japan
| | - Atsushi Mitsumoto
- Faculty of Pharmaceutical Sciences, Josai International University, 1 Gumyo, Togane, Chiba, 283-8555, Japan
| | - Yoichi Kawashima
- School of Pharmaceutical Sciences, Josai University, 1-1 Keyakidai, Sakado, Saitama, 350-0295, Japan
| | - Naomi Kudo
- School of Pharmaceutical Sciences, Josai University, 1-1 Keyakidai, Sakado, Saitama, 350-0295, Japan.
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204
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Jang CH, Kim KM, Yang JH, Cho SS, Kim SJ, Shin SM, Cho IJ, Ki SH. The Role of Lipin-1 in the Regulation of Fibrogenesis and TGF-β Signaling in Hepatic Stellate Cells. Toxicol Sci 2016; 153:28-38. [PMID: 27345520 DOI: 10.1093/toxsci/kfw109] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The adipogenic transcriptional regulation was reported to inhibit transdifferentiation of hepatic stellate cells (HSCs), which constitute the main fibrogenic cell type in the liver. Lipin-1 exhibits a dual function: an enzyme that catalyzes the conversion of phosphatidate to diacylglycerol and a transcriptional regulator. However, the involvement of Lipin-1 in the regulation of transforming growth factor-β (TGF-β) signaling and fibrogenesis in HSCs is not fully understood. Here, we showed that Lipin-1 was downregulated in activated primary HSCs and TGF-β-treated LX-2 cells, immortalized human HSC cell lines. The downregulation of Lipin-1 by TGF-β was not dependent on altered mRNA stability but rather on protein stability. Treatment of LX-2 cells with the proteasome inhibitor led to the accumulation of Lipin-1. Moreover, we observed a significant increase in Lipin-1 polyubiquitination. Overexpression of Lipin-1 attenuated TGF-β-induced fibrogenic gene expression. In addition, Lipin-1 inhibited TGF-β-mediated activation of Sma and Mad-related family (SMAD), a major transcription factor that transduces intracellular signals from TGF-β. Resveratrol, a well-known natural polyphenolic antioxidant, is known to inhibit liver fibrosis, although its mechanism of action remains unknown. Our data showed that resveratrol significantly increased the levels of Lipin-1 protein and mRNA in HSCs. Further investigation revealed that resveratrol blocked the polyubiquitination of Lipin-1. Resveratrol inhibited TGF-β-induced fibrogenic gene expression. TGF-β-induced SMAD binding element-luciferase reporter activity was significantly diminished by resveratrol with a simultaneous decrease in SMAD3 phosphorylation. Consistently, knockdown of the Lipin-1 gene using siRNA abolished the inhibitory effect of resveratrol. We conclude that Lipin-1 can antagonize HSC activation through the inhibition of TGF-β/SMAD signaling and that resveratrol may affect Lipin-1 gene induction and contribute to the inhibition of TGF-β-mediated hepatic fibrogenesis.
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Affiliation(s)
- Chang Ho Jang
- *College of Pharmacy, Chosun University, Gwangju, 61452, Korea
| | - Kyu Min Kim
- *College of Pharmacy, Chosun University, Gwangju, 61452, Korea College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 08826, Korea
| | - Ji Hye Yang
- *College of Pharmacy, Chosun University, Gwangju, 61452, Korea
| | - Sam Seok Cho
- *College of Pharmacy, Chosun University, Gwangju, 61452, Korea
| | - Seung Jung Kim
- *College of Pharmacy, Chosun University, Gwangju, 61452, Korea
| | - Sang Mi Shin
- *College of Pharmacy, Chosun University, Gwangju, 61452, Korea
| | - Il Je Cho
- MRC-GHF, College of Korean Medicine, Daegu Haany University, Gyeongsan, 38610, Korea
| | - Sung Hwan Ki
- *College of Pharmacy, Chosun University, Gwangju, 61452, Korea
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205
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Smulan LJ, Ding W, Freinkman E, Gujja S, Edwards YJK, Walker AK. Cholesterol-Independent SREBP-1 Maturation Is Linked to ARF1 Inactivation. Cell Rep 2016; 16:9-18. [PMID: 27320911 DOI: 10.1016/j.celrep.2016.05.086] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 04/29/2016] [Accepted: 05/22/2016] [Indexed: 11/19/2022] Open
Abstract
Lipogenesis requires coordinated expression of genes for fatty acid, phospholipid, and triglyceride synthesis. Transcription factors, such as SREBP-1 (Sterol regulatory element binding protein), may be activated in response to feedback mechanisms linking gene activation to levels of metabolites in the pathways. SREBPs can be regulated in response to membrane cholesterol and we also found that low levels of phosphatidylcholine (a methylated phospholipid) led to SBP-1/SREBP-1 maturation in C. elegans or mammalian models. To identify additional regulatory components, we performed a targeted RNAi screen in C. elegans, finding that both lpin-1/Lipin 1 (which converts phosphatidic acid to diacylglycerol) and arf-1.2/ARF1 (a GTPase regulating Golgi function) were important for low-PC activation of SBP-1/SREBP-1. Mechanistically linking the major hits of our screen, we find that limiting PC synthesis or LPIN1 knockdown in mammalian cells reduces the levels of active GTP-bound ARF1. Thus, changes in distinct lipid ratios may converge on ARF1 to increase SBP-1/SREBP-1 activity.
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Affiliation(s)
- Lorissa J Smulan
- Program in Molecular Medicine, UMASS Medical School, 373 Plantation Street, Worcester, MA 01605, USA
| | - Wei Ding
- Program in Molecular Medicine, UMASS Medical School, 373 Plantation Street, Worcester, MA 01605, USA
| | - Elizaveta Freinkman
- Metabolite Profiling Facility, Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, USA
| | - Sharvari Gujja
- Program in Molecular Medicine, UMASS Medical School, 373 Plantation Street, Worcester, MA 01605, USA
| | - Yvonne J K Edwards
- Program in Molecular Medicine, UMASS Medical School, 373 Plantation Street, Worcester, MA 01605, USA
| | - Amy K Walker
- Program in Molecular Medicine, UMASS Medical School, 373 Plantation Street, Worcester, MA 01605, USA.
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206
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Chen Y, Gall MG, Zhang H, Keane FM, McCaughan GW, Yu DMT, Gorrell MD. Dipeptidyl peptidase 9 enzymatic activity influences the expression of neonatal metabolic genes. Exp Cell Res 2016; 342:72-82. [PMID: 26930324 DOI: 10.1016/j.yexcr.2016.02.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Revised: 02/25/2016] [Accepted: 02/26/2016] [Indexed: 02/07/2023]
Abstract
The success of dipeptidyl peptidase 4 (DPP4) inhibition as a type 2 diabetes therapy has encouraged deeper examination of the post-proline DPP enzymes. DPP9 has been implicated in immunoregulation, disease pathogenesis and metabolism. The DPP9 enzyme-inactive (Dpp9 gene knock-in; Dpp9 gki) mouse displays neonatal lethality, suggesting that DPP9 enzyme activity is essential in neonatal development. Here we present gene expression patterns in these Dpp9 gki neonatal mice. Taqman PCR arrays and sequential qPCR assays on neonatal liver and gut revealed differential expression of genes involved in cell growth, innate immunity and metabolic pathways including long-chain-fatty-acid uptake and esterification, long-chain fatty acyl-CoA binding, trafficking and transport into mitochondria, lipoprotein metabolism, adipokine transport and gluconeogenesis in the Dpp9 gki mice compared to wild type. In a liver cell line, Dpp9 knockdown increased AMP-activated protein kinase phosphorylation, which suggests a potential mechanism. DPP9 protein levels in liver cells were altered by treatment with EGF, HGF, insulin or palmitate, suggesting potential natural DPP9 regulators. These gene expression analyses of a mouse strain deficient in DPP9 enzyme activity show, for the first time, that DPP9 enzyme activity regulates metabolic pathways in neonatal liver and gut.
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Affiliation(s)
- Yiqian Chen
- Centenary Institute and Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Margaret G Gall
- Centenary Institute and Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Hui Zhang
- Centenary Institute and Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Fiona M Keane
- Centenary Institute and Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Geoffrey W McCaughan
- Centenary Institute and Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Denise M T Yu
- Centenary Institute and Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Mark D Gorrell
- Centenary Institute and Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia.
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207
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Leikin-Frenkel A, Shomonov-Wagner L, Juknat A, Pasmanik-Chor M. Maternal Diet Enriched with α-Linolenic or Saturated Fatty Acids Differentially Regulates Gene Expression in the Liver of Mouse Offspring. JOURNAL OF NUTRIGENETICS AND NUTRIGENOMICS 2016; 8:185-94. [DOI: 10.1159/000442945] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 11/30/2015] [Indexed: 11/19/2022]
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208
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Abstract
In this review, Dorn et al. describe the regulatory circuitry and downstream events involved in mitochondrial biogenesis and its coordination with mitochondrial dynamics in developing and diseased hearts. The mitochondrion is a complex organelle that serves essential roles in energy transduction, ATP production, and a myriad of cellular signaling events. A finely tuned regulatory network orchestrates the biogenesis, maintenance, and turnover of mitochondria. The high-capacity mitochondrial system in the heart is regulated in a dynamic way to generate and consume enormous amounts of ATP in order to support the constant pumping function in the context of changing energy demands. This review describes the regulatory circuitry and downstream events involved in mitochondrial biogenesis and its coordination with mitochondrial dynamics in developing and diseased hearts.
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Affiliation(s)
- Gerald W Dorn
- Center for Pharmacogenomics, Washington University in St. Louis, St. Louis, Missouri 63110, USA
| | - Rick B Vega
- Cardiovascular Metabolism Program, Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida 32827, USA
| | - Daniel P Kelly
- Cardiovascular Metabolism Program, Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida 32827, USA
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209
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TEOFILOVIĆ A, BURSAĆ B, DJORDJEVIC A, VOJNOVIĆ MILUTINOVIĆ D, MATIĆ G, VELIČKOVIĆ N. High dietary fructose load aggravates lipid metabolism in the liver of Wistar rats through imbalance between lipogenesis and fatty acid oxidation. Turk J Biol 2016. [DOI: 10.3906/biy-1512-40] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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210
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Jaradat SA, Amayreh W, Al-Qa'qa' K, Krayyem J. Molecular analysis of LPIN1 in Jordanian patients with rhabdomyolysis. Meta Gene 2015; 7:90-4. [PMID: 26909335 PMCID: PMC4733219 DOI: 10.1016/j.mgene.2015.12.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 09/15/2015] [Accepted: 12/02/2015] [Indexed: 12/31/2022] Open
Abstract
Recessive mutations in LPIN1, which encodes a phosphatidate phosphatase enzyme, are a frequent cause of severe rhabdomyolysis in childhood. Hence, we sequenced the 19 coding exons of the gene in eight patients with recurrent hereditary myoglobinuria from four unrelated families in Jordan. The long-term goal is to facilitate molecular genetic diagnosis without the need for invasive procedures such as muscle biopsies. Three different mutations were detected, including the novel missense mutation c.2395G>C (Gly799Arg), which was found in two families. The two other mutations, c.2174G>A (Arg725His) and c.1162C>T (Arg388X), have been previously identified, and were found to cosegregate with the disease phenotype in the other two families. Intriguingly, patients homozygous for Arg725His were also homozygous for the c.1828C>T (Pro610Ser) polymorphism, and were exercise-intolerant between myoglobinuria episodes. Notably, patients homozygous for Arg388X were also homozygous for the c.2250G>C silent variant (Gly750Gly). Taken together, the data provide family-based evidence linking hereditary myoglobinuria to pathogenic variations in the C-terminal lipin domain of the enzyme. This finding highlights the functional significance of this domain in the absence of structural information. This is the first analysis of LPIN1 in myoglobinuria patients of Jordanian origin, and the fourth such analysis worldwide. LPIN1 mutations were cataloged in families with hereditary myoglobinuria. A novel missense Gly799Arg mutation was identified. Arg725His, the only other known missense mutation, was confirmed to be pathogenic. Arg388X, a known nonsense mutation, was the most common among Arabic patients. Patients exercise-intolerant between myoglobinuria episodes have a second mutation.
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Affiliation(s)
- Saied A Jaradat
- Princess Haya Biotechnology Center, Jordan University of Science and Technology, Irbid 22110, Jordan
| | - Wajdi Amayreh
- Department of Pediatrics, Metabolic Genetics Clinic, Queen Rania Al-Abdullah Children's Hospital, King Hussein Medical Centre, Amman 11855, Jordan
| | - Kefah Al-Qa'qa'
- Department of Pediatrics, Metabolic Genetics Clinic, Queen Rania Al-Abdullah Children's Hospital, King Hussein Medical Centre, Amman 11855, Jordan
| | - Jan Krayyem
- Princess Haya Biotechnology Center, Jordan University of Science and Technology, Irbid 22110, Jordan
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211
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Chae M, Jung JY, Bae IH, Kim HJ, Lee TR, Shin DW. Lipin-1 expression is critical for keratinocyte differentiation. J Lipid Res 2015; 57:563-73. [PMID: 26658689 DOI: 10.1194/jlr.m062588] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Indexed: 12/19/2022] Open
Abstract
Lipin-1 is an Mg(2+)-dependent phosphatidate phosphatase that facilitates the dephosphorylation of phosphatidic acid to generate diacylglycerol. Little is known about the expression and function of lipin-1 in normal human epidermal keratinocytes (NHEKs). Here, we demonstrate that lipin-1 is present in basal and spinous layers of the normal human epidermis, and lipin-1 expression is gradually downregulated during NHEK differentiation. Interestingly, lipin-1 knockdown (KD) inhibited keratinocyte differentiation and caused G1 arrest by upregulating p21 expression. Cell cycle arrest by p21 is required for commitment of keratinocytes to differentiation, but must be downregulated for the progress of keratinocyte differentiation. Therefore, reduced keratinocyte differentiation results from sustained upregulation of p21 by lipin-1 KD. Lipin-1 KD also decreased the phosphorylation/activation of protein kinase C (PKC)α, whereas lipin-1 overexpression increased PKCα phosphorylation. Treatment with PKCα inhibitors, like lipin-1 KD, stimulated p21 expression, while lipin-1 overexpression reduced p21 expression, implicating PKCα in lipin-1-induced regulation of p21 expression. Taken together, these results suggest that lipin-1-mediated downregulation of p21 is critical for the progress of keratinocyte differentiation after the initial commitment of keratinocytes to differentiation induced by p21, and that PKCα is involved in p21 expression regulation by lipin-1.
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Affiliation(s)
- Minjung Chae
- Bioscience Research Institute, Amorepacific Corporation R&D Center, Yongin-si, Gyeonggi-do, Republic of Korea
| | - Ji-Yong Jung
- Bioscience Research Institute, Amorepacific Corporation R&D Center, Yongin-si, Gyeonggi-do, Republic of Korea
| | - Il-Hong Bae
- Bioscience Research Institute, Amorepacific Corporation R&D Center, Yongin-si, Gyeonggi-do, Republic of Korea
| | - Hyoung-June Kim
- Bioscience Research Institute, Amorepacific Corporation R&D Center, Yongin-si, Gyeonggi-do, Republic of Korea
| | - Tae Ryong Lee
- Bioscience Research Institute, Amorepacific Corporation R&D Center, Yongin-si, Gyeonggi-do, Republic of Korea
| | - Dong Wook Shin
- Bioscience Research Institute, Amorepacific Corporation R&D Center, Yongin-si, Gyeonggi-do, Republic of Korea
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212
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Meijer IA, Sasarman F, Maftei C, Rossignol E, Vanasse M, Major P, Mitchell GA, Brunel-Guitton C. LPIN1 deficiency with severe recurrent rhabdomyolysis and persistent elevation of creatine kinase levels due to chromosome 2 maternal isodisomy. Mol Genet Metab Rep 2015. [PMID: 28649549 PMCID: PMC5471397 DOI: 10.1016/j.ymgmr.2015.10.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Fatty acid oxidation disorders and lipin-1 deficiency are the commonest genetic causes of rhabdomyolysis in children. We describe a lipin-1-deficient boy with recurrent, severe rhabdomyolytic episodes from the age of 4 years. Analysis of the LPIN1 gene that encodes lipin-1 revealed a novel homozygous frameshift mutation in exon 9, c.1381delC (p.Leu461SerfsX47), and complete uniparental isodisomy of maternal chromosome 2. This mutation is predicted to cause complete lipin-1 deficiency. The patient had six rhabdomyolytic crises, with creatine kinase (CK) levels up to 300,000 U/L (normal, 30 to 200). Plasma CK remained elevated between crises. A treatment protocol was instituted, with early aggressive monitoring, hydration, electrolyte replacement and high caloric, high carbohydrate intake. The patient received dexamethasone during two crises, which was well-tolerated and in these episodes, peak CK values were lower than in preceding episodes. Studies of anti-inflammatory therapy may be indicated in lipin-1 deficiency.
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Affiliation(s)
- I A Meijer
- Division of Pediatric Neurology, Department of Pediatrics, Université de Montréal, and CHU Sainte Justine, 3175 Côte Sainte-Catherine, Montreal, Quebec H3T 1C5, Canada
| | - F Sasarman
- Division of Biochemical Genetics Laboratory, Université de Montréal and CHU Sainte Justine, 3175 Côte Sainte-Catherine, Montreal, Quebec H3T 1C5, Canada
| | - C Maftei
- Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte Justine, 3175 Côte Sainte-Catherine, Montreal, Quebec H3T 1C5, Canada
| | - E Rossignol
- Division of Pediatric Neurology, Department of Pediatrics, Université de Montréal, and CHU Sainte Justine, 3175 Côte Sainte-Catherine, Montreal, Quebec H3T 1C5, Canada
| | - M Vanasse
- Division of Pediatric Neurology, Department of Pediatrics, Université de Montréal, and CHU Sainte Justine, 3175 Côte Sainte-Catherine, Montreal, Quebec H3T 1C5, Canada
| | - P Major
- Division of Pediatric Neurology, Department of Pediatrics, Université de Montréal, and CHU Sainte Justine, 3175 Côte Sainte-Catherine, Montreal, Quebec H3T 1C5, Canada
| | - G A Mitchell
- Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte Justine, 3175 Côte Sainte-Catherine, Montreal, Quebec H3T 1C5, Canada
| | - C Brunel-Guitton
- Division of Biochemical Genetics Laboratory, Université de Montréal and CHU Sainte Justine, 3175 Côte Sainte-Catherine, Montreal, Quebec H3T 1C5, Canada.,Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte Justine, 3175 Côte Sainte-Catherine, Montreal, Quebec H3T 1C5, Canada
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213
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Liu XP, Gao H, Huang XY, Chen YF, Feng XJ, He YH, Li ZM, Liu PQ. Peroxisome proliferator-activated receptor gamma coactivator 1 alpha protects cardiomyocytes from hypertrophy by suppressing calcineurin-nuclear factor of activated T cells c4 signaling pathway. Transl Res 2015; 166:459-473.e3. [PMID: 26118953 DOI: 10.1016/j.trsl.2015.06.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 05/21/2015] [Accepted: 06/02/2015] [Indexed: 01/11/2023]
Abstract
Peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) is a crucial coregulator interacting with multiple transcriptional factors in the regulation of cardiac hypertrophy. The present study revealed that PGC-1α protected cardiomyocytes from hypertrophy by suppressing calcineurin-nuclear factor of activated T cells c4 (NFATc4) signaling pathway. Overexpression of PGC-1α by adenovirus infection prevented the increased protein and messenger RNA expression of NFATc4 in phenylephrine (PE)-treated hypertrophic cardiomyocytes, whereas knockdown of PGC-1α by RNA silencing augmented the expression of NFATc4. An interaction between PGC-1α and NFATc4 was observed in both the cytoplasm and nucleus of neonatal rat cardiomyocytes. Adenovirus PGC-1α prevented the nuclear import of NFATc4 and increased its phosphorylation level of NFATc4, probably through repressing the expression and activity of calcineurin and interfering with the interaction between calcineurin and NFATc4. On the contrary, PGC-1α silencing aggravated PE-induced calcineurin activation, NFATc4 dephosphorylation, and nuclear translocation. Moreover, the binding activity and transcription activity of NFATc4 to DNA promoter of brain natriuretic peptide were abrogated by PGC-1α overexpression but were enhanced by PGC-1α knockdown. The effect of PGC-1α on suppressing the calcinuerin-NFATc4 signaling pathway might at least partially contribute to the protective effect of PGC-1α on cardiomyocyte hypertrophy. These findings provide novel insights into the role of PGC-1α in regulation of cardiac hypertrophy.
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Affiliation(s)
- Xue-Ping Liu
- Department of Pharmacology and Toxicology, School of Pharmaceutical Science, Sun Yat-Sen University, Guangzhou, PR China
| | - Hui Gao
- Department of Pharmacology and Toxicology, School of Pharmaceutical Science, Sun Yat-Sen University, Guangzhou, PR China; Department of Pharmacology, School of Medicine, Jishou University, Jishou, PR China
| | - Xiao-Yang Huang
- Department of Pharmacology and Toxicology, School of Pharmaceutical Science, Sun Yat-Sen University, Guangzhou, PR China
| | - Yan-Fang Chen
- Department of Pharmacy, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, PR China
| | - Xiao-Jun Feng
- Department of Pharmacology and Toxicology, School of Pharmaceutical Science, Sun Yat-Sen University, Guangzhou, PR China
| | - Yan-Hong He
- Department of Pharmacology and Toxicology, School of Pharmaceutical Science, Sun Yat-Sen University, Guangzhou, PR China
| | - Zhuo-Ming Li
- Department of Pharmacology and Toxicology, School of Pharmaceutical Science, Sun Yat-Sen University, Guangzhou, PR China.
| | - Pei-Qing Liu
- Department of Pharmacology and Toxicology, School of Pharmaceutical Science, Sun Yat-Sen University, Guangzhou, PR China.
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214
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El Kebbaj R, Andreoletti P, El Hajj HI, El Kharrassi Y, Vamecq J, Mandard S, Saih FE, Latruffe N, El Kebbaj MS, Lizard G, Nasser B, Cherkaoui-Malki M. Argan oil prevents down-regulation induced by endotoxin on liver fatty acid oxidation and gluconeogenesis and on peroxisome proliferator-activated receptor gamma coactivator-1α, (PGC-1α), peroxisome proliferator-activated receptor α (PPARα) and estrogen related receptor α (ERRα). BIOCHIMIE OPEN 2015; 1:51-59. [PMID: 29632829 PMCID: PMC5889474 DOI: 10.1016/j.biopen.2015.10.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 10/20/2015] [Indexed: 01/04/2023]
Abstract
In patients with sepsis, liver metabolism and its capacity to provide other organs with energetic substrates are impaired. This and many other pathophysiological changes seen in human patients are reproduced in mice injected with purified endotoxin (lipopolysaccharide, LPS). In the present study, down-regulation of genes involved in hepatic fatty acid oxidation (FAOx) and gluconeogenesis in mice exposed to LPS was challenged by nutritional intervention with Argan oil. Mice given a standard chow supplemented or not with either 6% (w/w) Argan oil (AO) or 6% (w/w) olive oil (OO) prior to exposure to LPS were explored for liver gene expressions assessed by mRNA transcript levels and/or enzyme activities. AO (or OO) food supplementation reveals that, in LPS-treated mice, hepatic expression of genes involved in FAOx and gluconeogenesis was preserved. This preventive protection might be related to the recovery of the gene expressions of nuclear receptors peroxisome proliferator-activated receptor α (PPARα) and estrogen related receptor α (ERRα) and their coactivator peroxisome proliferator-activated receptor gamma coactivator-1α, (PGC-1α). These preventive mechanisms conveyed by AO against LPS-induced metabolic dysregulation might add new therapeutic potentialities in the management of human sepsis. Argan oil prevents LPS-treated mice from liver dysregulation of FAOx and gluconeogenesis. Argan oil improves hepatic expression of PPARα and ERRα, and their coactivators PGC-1α and Lipin-1. New preventive mechanisms conveyed by Argan oil against LPS-induced metabolic dysregulation.
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Key Words
- ACADL, acyl CoA dehydrogenase long-chain
- ACADM, acyl CoA dehydrogenase medium-chain
- ACADS, acyl CoA dehydrogenase short-chain
- ACOX1, acyl-CoA oxidase 1
- AO, Argan oil
- Argan oil
- Beta-oxidation
- Coactivator
- ERRα, estrogen related receptor α
- G6PH, glucose-6-phosphatase
- Gluconeogenesis
- Glut2, glucose transporter 2
- Glut4, glucose transporter 4
- HNF-4α, hepatic nuclear factor-4α
- LPS, lipopolysaccharide
- Nuclear receptor
- OO, olive oil
- PEPCK, phospoenolpyruvate carboxykinase
- PGC-1α, peroxisome proliferator-activated receptor γ coactivator-1α
- PPARα, peroxisome proliferator-activated receptor α
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Affiliation(s)
- Riad El Kebbaj
- Univ. Bourgogne-Franche Comté, Laboratoire BioPeroxIL (Biochimie du Peroxysome, Inflammation et Métabolisme Lipidique), EA 7270, 21000 Dijon, France.,Laboratoir de Biochimie et Neurosciences, Faculté des Sciences et Techniques, Université Hassan I, BP 577, 26 000 Settat, Morocco.,Laboratoire des Sciences et Technologies de la Santé, Institut supérieur des sciences de la santé Université Hassan I, Route de Casablanca. 14 BP 539, 26 000 Settat, Morocco
| | - Pierre Andreoletti
- Univ. Bourgogne-Franche Comté, Laboratoire BioPeroxIL (Biochimie du Peroxysome, Inflammation et Métabolisme Lipidique), EA 7270, 21000 Dijon, France
| | - Hammam I El Hajj
- Univ. Bourgogne-Franche Comté, Laboratoire BioPeroxIL (Biochimie du Peroxysome, Inflammation et Métabolisme Lipidique), EA 7270, 21000 Dijon, France
| | - Youssef El Kharrassi
- Univ. Bourgogne-Franche Comté, Laboratoire BioPeroxIL (Biochimie du Peroxysome, Inflammation et Métabolisme Lipidique), EA 7270, 21000 Dijon, France.,Laboratoir de Biochimie et Neurosciences, Faculté des Sciences et Techniques, Université Hassan I, BP 577, 26 000 Settat, Morocco
| | - Joseph Vamecq
- INSERM and HMNO, CBP, CHRU Lille, 59037 Lille and RADEME EA 7364, Faculté de Médecine, Université de Lille 2, 59045 Lille, France
| | - Stéphane Mandard
- Lipness Team, INSERM, Research Center UMR866 and LabEx LipSTIC, Université de Bourgogne-Franche Comté, Dijon, France
| | - Fatima-Ezzahra Saih
- Univ. Bourgogne-Franche Comté, Laboratoire BioPeroxIL (Biochimie du Peroxysome, Inflammation et Métabolisme Lipidique), EA 7270, 21000 Dijon, France.,Laboratoir de Biochimie et Neurosciences, Faculté des Sciences et Techniques, Université Hassan I, BP 577, 26 000 Settat, Morocco
| | - Norbert Latruffe
- Univ. Bourgogne-Franche Comté, Laboratoire BioPeroxIL (Biochimie du Peroxysome, Inflammation et Métabolisme Lipidique), EA 7270, 21000 Dijon, France
| | - M'Hammed Saïd El Kebbaj
- Laboratoire de recherche sur les lipoprotéines et l'Athérosclérose, Faculté des Sciences Ben M'sik, Avenue Cdt Driss El Harti, BP 7955, Université Hassan II-Mohammedia-Casablanca, Morocco
| | - Gérard Lizard
- Univ. Bourgogne-Franche Comté, Laboratoire BioPeroxIL (Biochimie du Peroxysome, Inflammation et Métabolisme Lipidique), EA 7270, 21000 Dijon, France
| | - Boubker Nasser
- Laboratoir de Biochimie et Neurosciences, Faculté des Sciences et Techniques, Université Hassan I, BP 577, 26 000 Settat, Morocco
| | - Mustapha Cherkaoui-Malki
- Univ. Bourgogne-Franche Comté, Laboratoire BioPeroxIL (Biochimie du Peroxysome, Inflammation et Métabolisme Lipidique), EA 7270, 21000 Dijon, France
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215
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Schmitt S, Ugrankar R, Greene SE, Prajapati M, Lehmann M. Drosophila Lipin interacts with insulin and TOR signaling pathways in the control of growth and lipid metabolism. J Cell Sci 2015; 128:4395-406. [PMID: 26490996 DOI: 10.1242/jcs.173740] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 10/12/2015] [Indexed: 01/20/2023] Open
Abstract
Lipin proteins have key functions in lipid metabolism, acting as both phosphatidate phosphatases (PAPs) and nuclear regulators of gene expression. We show that the insulin and TORC1 pathways independently control functions of Drosophila Lipin (dLipin). Reduced signaling through the insulin receptor strongly enhanced defects caused by dLipin deficiency in fat body development, whereas reduced signaling through TORC1 led to translocation of dLipin into the nucleus. Reduced expression of dLipin resulted in decreased signaling through the insulin-receptor-controlled PI3K-Akt pathway and increased hemolymph sugar levels. Consistent with this, downregulation of dLipin in fat body cell clones caused a strong growth defect. The PAP but not the nuclear activity of dLipin was required for normal insulin pathway activity. Reduction of other enzymes of the glycerol-3 phosphate pathway affected insulin pathway activity in a similar manner, suggesting an effect that is mediated by one or more metabolites associated with the pathway. Taken together, our data show that dLipin is subject to intricate control by the insulin and TORC1 pathways, and that the cellular status of dLipin impacts how fat body cells respond to signals relayed through the PI3K-Akt pathway.
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Affiliation(s)
- Sandra Schmitt
- Department of Biological Sciences, SCEN 601, 1 University of Arkansas, Fayetteville, AR 72701, USA
| | - Rupali Ugrankar
- Department of Biological Sciences, SCEN 601, 1 University of Arkansas, Fayetteville, AR 72701, USA
| | - Stephanie E Greene
- Department of Biological Sciences, SCEN 601, 1 University of Arkansas, Fayetteville, AR 72701, USA
| | - Meenakshi Prajapati
- Department of Biological Sciences, SCEN 601, 1 University of Arkansas, Fayetteville, AR 72701, USA
| | - Michael Lehmann
- Department of Biological Sciences, SCEN 601, 1 University of Arkansas, Fayetteville, AR 72701, USA
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216
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Cardozo Gizzi AM, Prucca CG, Gaveglio VL, Renner ML, Pasquaré SJ, Caputto BL. The Catalytic Efficiency of Lipin 1β Increases by Physically Interacting with the Proto-oncoprotein c-Fos. J Biol Chem 2015; 290:29578-92. [PMID: 26475860 DOI: 10.1074/jbc.m115.678821] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Indexed: 01/19/2023] Open
Abstract
Phosphatidic acid (PA) is a central precursor for membrane phospholipid biosynthesis. The lipin family is a magnesium-dependent type I PA phosphatase involved in de novo synthesis of neutral lipids and phospholipids. The regulation of lipin activity may govern the pathways by which these lipids are synthesized and control the cellular levels of important signaling lipids. Moreover, the proto-oncoprotein c-Fos has an emerging role in glycerolipid synthesis regulation; by interacting with key synthesizing enzymes it is able to increase overall phospho- and glycolipid synthesis. We studied the lipin 1β enzyme activity in a cell-free system using PA/Triton X-100 mixed micelles as substrate, analyzing it in the presence/absence of c-Fos. We found that lipin 1β kcat value increases around 40% in the presence of c-Fos, with no change in the lipin 1β affinity for the PA/Triton X-100 mixed micelles. We also probed a physical interaction between both proteins. Although the c-Fos domain involved in lipin activation is its basic domain, the interaction domain is mapped to the N-terminal c-Fos. In conclusion, we provide evidence for a novel positive regulator of lipin 1β PA phosphatase activity that is not achieved via altering its subcellular localization or affinity for membranes but rather through directly increasing its catalytic efficiency.
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Affiliation(s)
- Andres M Cardozo Gizzi
- From the Centro de Investigaciones en Química Biológica de Córdoba (Consejo Nacional de Investigaciones Científicas y Técnicas), Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA Córdoba and
| | - Cesar G Prucca
- From the Centro de Investigaciones en Química Biológica de Córdoba (Consejo Nacional de Investigaciones Científicas y Técnicas), Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA Córdoba and
| | - Virginia L Gaveglio
- the Instituto de Investigaciones Bioquímicas de Bahía Blanca, Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Edificio El Camino La Carrindanga Km 7, 8000 Bahía Blanca, Argentina
| | - Marianne L Renner
- From the Centro de Investigaciones en Química Biológica de Córdoba (Consejo Nacional de Investigaciones Científicas y Técnicas), Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA Córdoba and
| | - Susana J Pasquaré
- the Instituto de Investigaciones Bioquímicas de Bahía Blanca, Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Edificio El Camino La Carrindanga Km 7, 8000 Bahía Blanca, Argentina
| | - Beatriz L Caputto
- From the Centro de Investigaciones en Química Biológica de Córdoba (Consejo Nacional de Investigaciones Científicas y Técnicas), Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA Córdoba and
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217
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Bruntz RC, Lindsley CW, Brown HA. Phospholipase D signaling pathways and phosphatidic acid as therapeutic targets in cancer. Pharmacol Rev 2015; 66:1033-79. [PMID: 25244928 DOI: 10.1124/pr.114.009217] [Citation(s) in RCA: 165] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Phospholipase D is a ubiquitous class of enzymes that generates phosphatidic acid as an intracellular signaling species. The phospholipase D superfamily plays a central role in a variety of functions in prokaryotes, viruses, yeast, fungi, plants, and eukaryotic species. In mammalian cells, the pathways modulating catalytic activity involve a variety of cellular signaling components, including G protein-coupled receptors, receptor tyrosine kinases, polyphosphatidylinositol lipids, Ras/Rho/ADP-ribosylation factor GTPases, and conventional isoforms of protein kinase C, among others. Recent findings have shown that phosphatidic acid generated by phospholipase D plays roles in numerous essential cellular functions, such as vesicular trafficking, exocytosis, autophagy, regulation of cellular metabolism, and tumorigenesis. Many of these cellular events are modulated by the actions of phosphatidic acid, and identification of two targets (mammalian target of rapamycin and Akt kinase) has especially highlighted a role for phospholipase D in the regulation of cellular metabolism. Phospholipase D is a regulator of intercellular signaling and metabolic pathways, particularly in cells that are under stress conditions. This review provides a comprehensive overview of the regulation of phospholipase D activity and its modulation of cellular signaling pathways and functions.
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Affiliation(s)
- Ronald C Bruntz
- Department of Pharmacology (R.C.B., C.W.L., H.A.B.) and Vanderbilt Center for Neuroscience Drug Discovery (C.W.L.), Vanderbilt University Medical Center; Department of Chemistry, Vanderbilt Institute of Chemical Biology (C.W.L., H.A.B.); Vanderbilt Specialized Chemistry for Accelerated Probe Development (C.W.L.); and Department of Biochemistry, Vanderbilt-Ingram Cancer Center (H.A.B.), Vanderbilt University, Nashville, Tennessee
| | - Craig W Lindsley
- Department of Pharmacology (R.C.B., C.W.L., H.A.B.) and Vanderbilt Center for Neuroscience Drug Discovery (C.W.L.), Vanderbilt University Medical Center; Department of Chemistry, Vanderbilt Institute of Chemical Biology (C.W.L., H.A.B.); Vanderbilt Specialized Chemistry for Accelerated Probe Development (C.W.L.); and Department of Biochemistry, Vanderbilt-Ingram Cancer Center (H.A.B.), Vanderbilt University, Nashville, Tennessee
| | - H Alex Brown
- Department of Pharmacology (R.C.B., C.W.L., H.A.B.) and Vanderbilt Center for Neuroscience Drug Discovery (C.W.L.), Vanderbilt University Medical Center; Department of Chemistry, Vanderbilt Institute of Chemical Biology (C.W.L., H.A.B.); Vanderbilt Specialized Chemistry for Accelerated Probe Development (C.W.L.); and Department of Biochemistry, Vanderbilt-Ingram Cancer Center (H.A.B.), Vanderbilt University, Nashville, Tennessee
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218
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Xu W, Barrientos T, Mao L, Rockman HA, Sauve AA, Andrews NC. Lethal Cardiomyopathy in Mice Lacking Transferrin Receptor in the Heart. Cell Rep 2015; 13:533-545. [PMID: 26456827 DOI: 10.1016/j.celrep.2015.09.023] [Citation(s) in RCA: 205] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 08/21/2015] [Accepted: 09/04/2015] [Indexed: 01/26/2023] Open
Abstract
Both iron overload and iron deficiency have been associated with cardiomyopathy and heart failure, but cardiac iron utilization is incompletely understood. We hypothesized that the transferrin receptor (Tfr1) might play a role in cardiac iron uptake and used gene targeting to examine the role of Tfr1 in vivo. Surprisingly, we found that decreased iron, due to inactivation of Tfr1, was associated with severe cardiac consequences. Mice lacking Tfr1 in the heart died in the second week of life and had cardiomegaly, poor cardiac function, failure of mitochondrial respiration, and ineffective mitophagy. The phenotype could only be rescued by aggressive iron therapy, but it was ameliorated by administration of nicotinamide riboside, an NAD precursor. Our findings underscore the importance of both Tfr1 and iron in the heart, and may inform therapy for patients with heart failure.
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Affiliation(s)
- Wenjing Xu
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Duke University, Durham, NC 27705, USA
| | - Tomasa Barrientos
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Duke University, Durham, NC 27705, USA
| | - Lan Mao
- Department of Medicine, Duke University School of Medicine, Duke University, Durham, NC 27705, USA
| | - Howard A Rockman
- Department of Medicine, Duke University School of Medicine, Duke University, Durham, NC 27705, USA
| | - Anthony A Sauve
- Department of Pharmacology, Weill Cornell Medical College, Cornell University, New York, NY 10065, USA
| | - Nancy C Andrews
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Duke University, Durham, NC 27705, USA; Department of Pediatrics, Duke University School of Medicine, Duke University, Durham, NC 27705, USA.
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219
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Resnyk CW, Chen C, Huang H, Wu CH, Simon J, Le Bihan-Duval E, Duclos MJ, Cogburn LA. RNA-Seq Analysis of Abdominal Fat in Genetically Fat and Lean Chickens Highlights a Divergence in Expression of Genes Controlling Adiposity, Hemostasis, and Lipid Metabolism. PLoS One 2015; 10:e0139549. [PMID: 26445145 PMCID: PMC4596860 DOI: 10.1371/journal.pone.0139549] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 09/14/2015] [Indexed: 01/20/2023] Open
Abstract
Genetic selection for enhanced growth rate in meat-type chickens (Gallus domesticus) is usually accompanied by excessive adiposity, which has negative impacts on both feed efficiency and carcass quality. Enhanced visceral fatness and several unique features of avian metabolism (i.e., fasting hyperglycemia and insulin insensitivity) mimic overt symptoms of obesity and related metabolic disorders in humans. Elucidation of the genetic and endocrine factors that contribute to excessive visceral fatness in chickens could also advance our understanding of human metabolic diseases. Here, RNA sequencing was used to examine differential gene expression in abdominal fat of genetically fat and lean chickens, which exhibit a 2.8-fold divergence in visceral fatness at 7 wk. Ingenuity Pathway Analysis revealed that many of 1687 differentially expressed genes are associated with hemostasis, endocrine function and metabolic syndrome in mammals. Among the highest expressed genes in abdominal fat, across both genotypes, were 25 differentially expressed genes associated with de novo synthesis and metabolism of lipids. Over-expression of numerous adipogenic and lipogenic genes in the FL chickens suggests that in situ lipogenesis in chickens could make a more substantial contribution to expansion of visceral fat mass than previously recognized. Distinguishing features of the abdominal fat transcriptome in lean chickens were high abundance of multiple hemostatic and vasoactive factors, transporters, and ectopic expression of several hormones/receptors, which could control local vasomotor tone and proteolytic processing of adipokines, hemostatic factors and novel endocrine factors. Over-expression of several thrombogenic genes in abdominal fat of lean chickens is quite opposite to the pro-thrombotic state found in obese humans. Clearly, divergent genetic selection for an extreme (2.5-2.8-fold) difference in visceral fatness provokes a number of novel regulatory responses that govern growth and metabolism of visceral fat in this unique avian model of juvenile-onset obesity and glucose-insulin imbalance.
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Affiliation(s)
- Christopher W. Resnyk
- Department of Animal and Food Sciences, University of Delaware, Newark, Delaware, United States of America
| | - Chuming Chen
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, Delaware, United States of America
| | - Hongzhan Huang
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, Delaware, United States of America
| | - Cathy H. Wu
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, Delaware, United States of America
| | - Jean Simon
- INRA UR83 Recherches Avicoles, 37380, Nouzilly, France
| | | | | | - Larry A. Cogburn
- Department of Animal and Food Sciences, University of Delaware, Newark, Delaware, United States of America
- * E-mail:
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220
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McCommis KS, Chen Z, Fu X, McDonald WG, Colca JR, Kletzien RF, Burgess SC, Finck BN. Loss of Mitochondrial Pyruvate Carrier 2 in the Liver Leads to Defects in Gluconeogenesis and Compensation via Pyruvate-Alanine Cycling. Cell Metab 2015; 22:682-94. [PMID: 26344101 PMCID: PMC4598280 DOI: 10.1016/j.cmet.2015.07.028] [Citation(s) in RCA: 158] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 06/29/2015] [Accepted: 07/30/2015] [Indexed: 01/04/2023]
Abstract
Pyruvate transport across the inner mitochondrial membrane is believed to be a prerequisite for gluconeogenesis in hepatocytes, which is important for the maintenance of normoglycemia during prolonged food deprivation but also contributes to hyperglycemia in diabetes. To determine the requirement for mitochondrial pyruvate import in gluconeogenesis, mice with liver-specific deletion of mitochondrial pyruvate carrier 2 (LS-Mpc2(-/-)) were generated. Loss of MPC2 impaired, but did not completely abolish, hepatocyte conversion of labeled pyruvate to TCA cycle intermediates and glucose. Unbiased metabolomic analyses of livers from fasted LS-Mpc2(-/-) mice suggested that alterations in amino acid metabolism, including pyruvate-alanine cycling, might compensate for the loss of MPC2. Indeed, inhibition of pyruvate-alanine transamination further reduced mitochondrial pyruvate metabolism and glucose production by LS-Mpc2(-/-) hepatocytes. These data demonstrate an important role for MPC2 in controlling hepatic gluconeogenesis and illuminate a compensatory mechanism for circumventing a block in mitochondrial pyruvate import.
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Affiliation(s)
- Kyle S McCommis
- Division of Geriatrics and Nutritional Sciences, Center for Human Nutrition, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Zhouji Chen
- Division of Geriatrics and Nutritional Sciences, Center for Human Nutrition, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Xiaorong Fu
- Advanced Imaging Research Center and Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | | | - Jerry R Colca
- Metabolic Solutions Development Company, Kalamazoo, MI 49007, USA
| | - Rolf F Kletzien
- Metabolic Solutions Development Company, Kalamazoo, MI 49007, USA
| | - Shawn C Burgess
- Advanced Imaging Research Center and Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Brian N Finck
- Division of Geriatrics and Nutritional Sciences, Center for Human Nutrition, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA.
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221
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Domitrović R, Potočnjak I. A comprehensive overview of hepatoprotective natural compounds: mechanism of action and clinical perspectives. Arch Toxicol 2015; 90:39-79. [DOI: 10.1007/s00204-015-1580-z] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 08/11/2015] [Indexed: 12/22/2022]
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222
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Arretxe E, Armengol S, Mula S, Chico Y, Ochoa B, Martínez MJ. Profiling of promoter occupancy by the SND1 transcriptional coactivator identifies downstream glycerolipid metabolic genes involved in TNFα response in human hepatoma cells. Nucleic Acids Res 2015; 43:10673-88. [PMID: 26323317 PMCID: PMC4678849 DOI: 10.1093/nar/gkv858] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 08/17/2015] [Indexed: 01/07/2023] Open
Abstract
The NF-κB-inducible Staphylococcal nuclease and tudor domain-containing 1 gene (SND1) encodes a coactivator involved in inflammatory responses and tumorigenesis. While SND1 is known to interact with certain transcription factors and activate client gene expression, no comprehensive mapping of SND1 target genes has been reported. Here, we have approached this question by performing ChIP-chip assays on human hepatoma HepG2 cells and analyzing SND1 binding modulation by proinflammatory TNFα. We show that SND1 binds 645 gene promoters in control cells and 281 additional genes in TNFα-treated cells. Transcription factor binding site analysis of bound probes identified motifs for established partners and for novel transcription factors including HSF, ATF, STAT3, MEIS1/AHOXA9, E2F and p300/CREB. Major target genes were involved in gene expression and RNA metabolism regulation, as well as development and cellular metabolism. We confirmed SND1 binding to 21 previously unrecognized genes, including a set of glycerolipid genes. Knocking-down experiments revealed that SND1 deficiency compromises the glycerolipid gene reprogramming and lipid phenotypic responses to TNFα. Overall, our findings uncover an unexpected large set of potential SND1 target genes and partners and reveal SND1 to be a determinant downstream effector of TNFα that contributes to support glycerophospholipid homeostasis in human hepatocellular carcinoma during inflammation.
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Affiliation(s)
- Enara Arretxe
- Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country (UPV/EHU), 48940 Leioa, Bizkaia, Spain
| | - Sandra Armengol
- Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country (UPV/EHU), 48940 Leioa, Bizkaia, Spain
| | - Sarai Mula
- Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country (UPV/EHU), 48940 Leioa, Bizkaia, Spain
| | - Yolanda Chico
- Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country (UPV/EHU), 48940 Leioa, Bizkaia, Spain
| | - Begoña Ochoa
- Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country (UPV/EHU), 48940 Leioa, Bizkaia, Spain
| | - María José Martínez
- Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country (UPV/EHU), 48940 Leioa, Bizkaia, Spain
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223
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Jiang W, Zhu J, Zhuang X, Zhang X, Luo T, Esser KA, Ren H. Lipin1 Regulates Skeletal Muscle Differentiation through Extracellular Signal-regulated Kinase (ERK) Activation and Cyclin D Complex-regulated Cell Cycle Withdrawal. J Biol Chem 2015; 290:23646-55. [PMID: 26296887 DOI: 10.1074/jbc.m115.686519] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Indexed: 12/20/2022] Open
Abstract
Lipin1, an intracellular protein, plays critical roles in controlling lipid synthesis and energy metabolism through its enzymatic activity and nuclear transcriptional functions. Several mouse models of skeletal muscle wasting are associated with lipin1 mutation or altered expression. Recent human studies have suggested that children with homozygous null mutations in the LPIN1 gene suffer from rhabdomyolysis. However, the underlying pathophysiologic mechanism is still poorly understood. In the present study we examined whether lipin1 contributes to regulating muscle regeneration. We characterized the time course of skeletal muscle regeneration in lipin1-deficient fld mice after injury. We found that fld mice exhibited smaller regenerated muscle fiber cross-sectional areas compared with wild-type mice in response to injury. Our results from a series of in vitro experiments suggest that lipin1 is up-regulated and translocated to the nucleus during myoblast differentiation and plays a key role in myogenesis by regulating the cytosolic activation of ERK1/2 to form a complex and a downstream effector cyclin D3-mediated cell cycle withdrawal. Overall, our study reveals a previously unknown role of lipin1 in skeletal muscle regeneration and expands our understanding of the cellular and molecular mechanisms underlying skeletal muscle regeneration.
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Affiliation(s)
- Weihua Jiang
- From the Division of Cardiovascular Medicine, Department of Internal Medicine, Saha Cardiovascular Center
| | - Jing Zhu
- From the Division of Cardiovascular Medicine, Department of Internal Medicine, Saha Cardiovascular Center
| | - Xun Zhuang
- From the Division of Cardiovascular Medicine, Department of Internal Medicine, Saha Cardiovascular Center
| | - Xiping Zhang
- Department of Physiology, University of Kentucky, Lexington, Kentucky 40536
| | - Tao Luo
- From the Division of Cardiovascular Medicine, Department of Internal Medicine, Saha Cardiovascular Center
| | - Karyn A Esser
- Department of Physiology, University of Kentucky, Lexington, Kentucky 40536
| | - Hongmei Ren
- From the Division of Cardiovascular Medicine, Department of Internal Medicine, Saha Cardiovascular Center,
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224
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Navratil AR, Vozenilek AE, Cardelli JA, Green JM, Thomas MJ, Sorci-Thomas MG, Orr AW, Woolard MD. Lipin-1 contributes to modified low-density lipoprotein-elicited macrophage pro-inflammatory responses. Atherosclerosis 2015; 242:424-32. [PMID: 26288136 DOI: 10.1016/j.atherosclerosis.2015.08.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 07/28/2015] [Accepted: 08/06/2015] [Indexed: 12/13/2022]
Abstract
Atherosclerosis is a chronic inflammatory disease of large and medium-sized arteries and the underlying cause of cardiovascular disease, a major cause of mortality worldwide. The over-accumulation of modified cholesterol-containing low-density lipoproteins (e.g. oxLDL) in the artery wall and the subsequent recruitment and activation of macrophages contributes to the development of atherosclerosis. The excessive uptake of modified-LDL by macrophages leads to a lipid-laden "foamy" phenotype and pro-inflammatory cytokine production. Modified-LDLs promote foam cell formation in part by stimulating de novo lipid biosynthesis. However, it is unknown if lipid biosynthesis directly regulates foam cell pro-inflammatory mediator production. Lipin-1, a phosphatidate phosphohydrolase required for the generation of diacylglycerol during glycerolipid synthesis has recently been demonstrated to contribute to bacterial-induced pro-inflammatory responses by macrophages. In this study we present evidence demonstrating the presence of lipin-1 within macrophages in human atherosclerotic plaques. Additionally, reducing lipin-1 levels in macrophages significantly inhibits both modified-LDL-induced foam cell formation in vitro, as observed by smaller/fewer intracellular lipid inclusions, and ablates modified-LDL-elicited production of the pro-atherogenic mediators tumor necrosis factor-α, interleukin-6, and prostaglandin E2. These findings demonstrate a critical role for lipin-1 in the regulation of macrophage inflammatory responses to modified-LDL. These data begin to link the processes of foam cell formation and pro-inflammatory cytokine production within macrophages.
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Affiliation(s)
- Aaron R Navratil
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center at Shreveport, Shreveport, LA 71130, USA.
| | - Aimee E Vozenilek
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center at Shreveport, Shreveport, LA 71130, USA.
| | - James A Cardelli
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center at Shreveport, Shreveport, LA 71130, USA; Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center at Shreveport, Shreveport, LA 71130, USA.
| | - Jonette M Green
- Department of Pathology, Louisiana State University Health Sciences Center at Shreveport, Shreveport, LA 71130, USA.
| | - Michael J Thomas
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
| | - Mary G Sorci-Thomas
- Department of Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, USA; Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
| | - A Wayne Orr
- Department of Pathology, Louisiana State University Health Sciences Center at Shreveport, Shreveport, LA 71130, USA.
| | - Matthew D Woolard
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center at Shreveport, Shreveport, LA 71130, USA.
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225
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Ji Y, Wu Z, Dai Z, Sun K, Wang J, Wu G. Nutritional epigenetics with a focus on amino acids: implications for the development and treatment of metabolic syndrome. J Nutr Biochem 2015; 27:1-8. [PMID: 26427799 DOI: 10.1016/j.jnutbio.2015.08.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 07/31/2015] [Accepted: 08/05/2015] [Indexed: 12/31/2022]
Abstract
Recent findings from human and animal studies indicate that maternal undernutrition or overnutrition affects covalent modifications of the fetal genome and its associated histones that can be carried forward to subsequent generations. An adverse outcome of maternal malnutrition is the development of metabolic syndrome, which is defined as a cluster of disorders including obesity, hyperglycemia, hyperinsulinemia, hyperlipidemia, hypertension and insulin resistance. The transgenerational impacts of maternal nutrition are known as fetal programming, which is mediated by stable and heritable alterations of gene expression through covalent modifications of DNA and histones without changes in DNA sequences (namely, epigenetics). The underlying mechanisms include chromatin remodeling, DNA methylation (occurring at the 5'-position of cytosine residues within CpG dinucleotides), histone modifications (acetylation, methylation, phosphorylation, ubiquitination and sumoylation) and expression and activity of small noncoding RNAs. The enzymes catalyzing these reactions include S-adenosylmethionine-dependent DNA and protein methyltransferases, DNA demethylases, histone acetylase (lysine acetyltransferase), general control nonderepressible 5 (GCN5)-related N-acetyltransferase (a superfamily of acetyltransferase) and histone deacetylase. Amino acids (e.g., glycine, histidine, methionine and serine) and vitamins (B6, B12 and folate) play key roles in provision of methyl donors for DNA and protein methylation. Therefore, these nutrients and related metabolic pathways are of interest in dietary treatment of metabolic syndrome. Intervention strategies include targeting epigenetically disturbed metabolic pathways through dietary supplementation with nutrients (particularly functional amino acids and vitamins) to regulate one-carbon-unit metabolism, antioxidative reactions and gene expression, as well as protein methylation and acetylation. These mechanism-based approaches may effectively improve health and well-being of affected offspring.
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Affiliation(s)
- Yun Ji
- State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing 100193, China
| | - Zhenlong Wu
- State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing 100193, China.
| | - Zhaolai Dai
- State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing 100193, China
| | - Kaiji Sun
- State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing 100193, China
| | - Junjun Wang
- State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing 100193, China
| | - Guoyao Wu
- State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing 100193, China; Department of Animal Science and Center for Animal Genomics, Texas A&M University, College Station, TX 77843, USA
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226
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CHO JINKYUNG, KIM SHINUK, LEE SHINHO, KANG HYUNSIK. Effect of Training Intensity on Nonalcoholic Fatty Liver Disease. Med Sci Sports Exerc 2015; 47:1624-34. [DOI: 10.1249/mss.0000000000000595] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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227
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Houlahan KE, Prokopec SD, Sun RX, Moffat ID, Lindén J, Lensu S, Okey AB, Pohjanvirta R, Boutros PC. Transcriptional profiling of rat white adipose tissue response to 2,3,7,8-tetrachlorodibenzo-ρ-dioxin. Toxicol Appl Pharmacol 2015; 288:223-31. [PMID: 26232522 DOI: 10.1016/j.taap.2015.07.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 07/18/2015] [Accepted: 07/21/2015] [Indexed: 12/21/2022]
Abstract
Polychlorinated dibenzodioxins are environmental contaminants commonly produced as a by-product of industrial processes. The most potent of these, 2,3,7,8-tetrachlorodibenzo-ρ-dioxin (TCDD), is highly lipophilic, leading to bioaccumulation. White adipose tissue (WAT) is a major site for energy storage, and is one of the organs in which TCDD accumulates. In laboratory animals, exposure to TCDD causes numerous metabolic abnormalities, including a wasting syndrome. We therefore investigated the molecular effects of TCDD exposure on WAT by profiling the transcriptomic response of WAT to 100μg/kg of TCDD at 1 or 4days in TCDD-sensitive Long-Evans (Turku/AB; L-E) rats. A comparative analysis was conducted simultaneously in identically treated TCDD-resistant Han/Wistar (Kuopio; H/W) rats one day after exposure to the same dose. We sought to identify transcriptomic changes coinciding with the onset of toxicity, while gaining additional insight into later responses. More transcriptional responses to TCDD were observed at 4days than at 1day post-exposure, suggesting WAT shows mostly secondary responses. Two classic AHR-regulated genes, Cyp1a1 and Nqo1, were significantly induced by TCDD in both strains, while several genes involved in the immune response, including Ms4a7 and F13a1 were altered in L-E rats alone. We compared genes affected by TCDD in rat WAT and human adipose cells, and observed little overlap. Interestingly, very few genes involved in lipid metabolism exhibited altered expression levels despite the pronounced lipid mobilization from peripheral fat pads by TCDD in L-E rats. Of these genes, the lipolysis-associated Lpin1 was induced slightly over 2-fold in L-E rat WAT on day 4.
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Affiliation(s)
- Kathleen E Houlahan
- Informatics and Bio-Computing Program, Ontario Institute for Cancer Research, Toronto, Canada
| | - Stephenie D Prokopec
- Informatics and Bio-Computing Program, Ontario Institute for Cancer Research, Toronto, Canada
| | - Ren X Sun
- Informatics and Bio-Computing Program, Ontario Institute for Cancer Research, Toronto, Canada
| | - Ivy D Moffat
- Department of Pharmacology & Toxicology, University of Toronto, Toronto, Canada
| | - Jere Lindén
- Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
| | - Sanna Lensu
- Department of Biology of Physical Activity, University of Jyväskylä, Jyväskylä, Finland; Department of Environmental Health, National Institute for Health and Welfare, Kuopio, Finland
| | - Allan B Okey
- Department of Pharmacology & Toxicology, University of Toronto, Toronto, Canada
| | - Raimo Pohjanvirta
- Department of Food Hygiene and Environmental Health, University of Helsinki, Helsinki, Finland.
| | - Paul C Boutros
- Informatics and Bio-Computing Program, Ontario Institute for Cancer Research, Toronto, Canada; Department of Pharmacology & Toxicology, University of Toronto, Toronto, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Canada.
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228
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Hamel Y, Mamoune A, Mauvais FX, Habarou F, Lallement L, Romero NB, Ottolenghi C, de Lonlay P. Acute rhabdomyolysis and inflammation. J Inherit Metab Dis 2015; 38:621-8. [PMID: 25778939 DOI: 10.1007/s10545-015-9827-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 02/10/2015] [Accepted: 02/11/2015] [Indexed: 02/07/2023]
Abstract
Rhabdomyolysis results from the rapid breakdown of skeletal muscle fibers, which leads to leakage of potentially toxic cellular content into the systemic circulation. Acquired causes by direct injury to the sarcolemma are most frequent. The inherited causes are: i) metabolic with failure of energy production, including mitochondrial fatty acid ß-oxidation defects, LPIN1 mutations, inborn errors of glycogenolysis and glycolysis, more rarely mitochondrial respiratory chain deficiency, purine defects and peroxysomal α-methyl-acyl-CoA-racemase defect (AMACR), ii) structural causes with muscle dystrophies and myopathies, iii) calcium pump disorder with RYR1 gene mutations, iv) inflammatory causes with myositis. Irrespective of the cause of rhabdomyolysis, the pathology follows a common pathway, either by the direct injury to sarcolemma by increased intracellular calcium concentration (acquired causes) or by the failure of energy production (inherited causes), which leads to fiber necrosis. Rhabdomyolysis are frequently precipitated by febrile illness or exercise. These conditions are associated with two events, elevated temperature and high circulating levels of pro-inflammatory mediators such as cytokines and chemokines. To illustrate these points in the context of energy metabolism, protein thermolability and the potential benefits of arginine therapy, we focus on a rare cause of rhabdomyolysis, aldolase A deficiency. In addition, our studies on lipin-1 (LPIN1) deficiency raise the possibility that several diseases involved in rhabdomyolysis implicate pro-inflammatory cytokines and may even represent primarily pro-inflammatory diseases. Thus, not only thermolability of mutant proteins critical for muscle function, but also pro-inflammatory cytokines per se, may lead to metabolic decompensation and rhabdomyolysis.
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Affiliation(s)
- Yamina Hamel
- Institut Imagine, Institut National de la Santé et de la Recherche Médicale, Unité 1163, 75015, Paris, France
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229
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González-Reimers E, Quintero-Platt G, Rodríguez-Gaspar M, Alemán-Valls R, Pérez-Hernández O, Santolaria-Fernández F. Liver steatosis in hepatitis C patients. World J Hepatol 2015; 7:1337-1346. [PMID: 26052379 PMCID: PMC4450197 DOI: 10.4254/wjh.v7.i10.1337] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 01/31/2015] [Accepted: 03/09/2015] [Indexed: 02/06/2023] Open
Abstract
There is controversy regarding some aspects of hepatitis C virus (HCV) infection-associated liver steatosis, and their relationship with body fat stores. It has classically been found that HCV, especially genotype 3, exerts direct metabolic effects which lead to liver steatosis. This supports the existence of a so called viral steatosis and a metabolic steatosis, which would affect HCV patients who are also obese or diabetics. In fact, several genotypes exert metabolic effects which overlap with some of those observed in the metabolic syndrome. In this review we will analyse the pathogenic pathways involved in the development of steatosis in HCV patients. Several cytokines and adipokines also become activated and are involved in “pure” steatosic effects, in addition to inflammation. They are probably responsible for the evolution of simple steatosis to steatohepatitis, making it difficult to explain why such alterations only affect a proportion of steatosic patients.
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230
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You M, Jogasuria A, Taylor C, Wu J. Sirtuin 1 signaling and alcoholic fatty liver disease. Hepatobiliary Surg Nutr 2015; 4:88-100. [PMID: 26005675 DOI: 10.3978/j.issn.2304-3881.2014.12.06] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Accepted: 10/29/2014] [Indexed: 12/12/2022]
Abstract
Alcoholic fatty liver disease (AFLD) is one of the most prevalent forms of liver disease worldwide and can progress to inflammation (hepatitis), fibrosis/cirrhosis, and ultimately lead to end stage liver injury. The mechanisms, by which ethanol consumption leads to AFLD, are complicated and multiple, and remain incompletely understood. Nevertheless, understanding its pathogenesis will facilitate the development of effective pharmacological or nutritional therapies for treating human AFLD. Chronic ethanol consumption causes steatosis and inflammation in rodents or humans by disturbing several important hepatic transcriptional regulators, including AMP-activated kinase (AMPK), lipin-1, sterol regulatory element binding protein 1 (SREBP-1), PPARγ co-activator-1α (PGC-1α), and nuclear transcription factor-κB (NF-κB). Remarkably, the effects of ethanol on these regulators are mediated in whole or in part by inhibition of a central signaling molecule, sirtuin 1 (SIRT1), which is a nicotinamide adenine dinucleotide (NAD(+), NADH)-dependent class III protein deacetylase. In recent years, SIRT1 has emerged as a pivotal molecule controlling the pathways of hepatic lipid metabolism, inflammatory responses and in the development of AFLD in rodents and in humans. Ethanol-mediated SIRT1 inhibition suppresses or stimulates the activities of above described transcriptional regulators and co-regulators, thereby deregulating diverse lipid metabolism and inflammatory response pathways including lipogenesis, fatty acid β-oxidation, lipoprotein uptake and secretion and expression of pro-inflammatory cytokines in the liver. This review aims to highlight our current understanding of SIRT1 regulatory mechanisms and its response to ethanol-induced toxicity, thus, affirming significant role of SIRT1 signaling in the development of AFLD.
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Affiliation(s)
- Min You
- Department of Pharmaceutical Sciences, College of Pharmacy, Northeast Ohio Medical University, Rootstown, OH 44272, USA
| | - Alvin Jogasuria
- Department of Pharmaceutical Sciences, College of Pharmacy, Northeast Ohio Medical University, Rootstown, OH 44272, USA
| | - Charles Taylor
- Department of Pharmaceutical Sciences, College of Pharmacy, Northeast Ohio Medical University, Rootstown, OH 44272, USA
| | - Jiashin Wu
- Department of Pharmaceutical Sciences, College of Pharmacy, Northeast Ohio Medical University, Rootstown, OH 44272, USA
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231
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Rhabdomyolysis-Associated Mutations in Human LPIN1 Lead to Loss of Phosphatidic Acid Phosphohydrolase Activity. JIMD Rep 2015; 23:113-22. [PMID: 25967228 DOI: 10.1007/8904_2015_440] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 04/06/2015] [Accepted: 04/08/2015] [Indexed: 12/18/2022] Open
Abstract
Rhabdomyolysis is an acute syndrome due to extensive injury of skeletal muscle. Recurrent rhabdomyolysis is often caused by inborn errors in intermediary metabolism, and recent work has suggested that mutations in the human gene encoding lipin 1 (LPIN1) may be a common cause of recurrent rhabdomyolysis in children. Lipin 1 dephosphorylates phosphatidic acid to form diacylglycerol (phosphatidic acid phosphohydrolase; PAP) and acts as a transcriptional regulatory protein to control metabolic gene expression. Herein, a 3-year-old boy with severe recurrent rhabdomyolysis was determined to be a compound heterozygote for a novel c.1904T>C (p.Leu635Pro) substitution and a previously reported genomic deletion of exons 18-19 (E766-S838_del) in LPIN1. Western blotting with patient muscle biopsy lysates demonstrated a marked reduction in lipin 1 protein, while immunohistochemical staining for lipin 1 showed abnormal subcellular localization. We cloned cDNAs to express recombinant lipin 1 proteins harboring pathogenic mutations and showed that the E766-S838_del allele was not expressed at the RNA or protein level. Lipin 1 p.Leu635Pro was expressed, but the protein was less stable, was aggregated in the cytosol, and was targeted for proteosomal degradation. Another pathogenic single amino acid substitution, lipin 1 p.Arg725His, was well expressed and retained its transcriptional regulatory function. However, both p.Leu635Pro and p.Arg725His proteins were found to be deficient in PAP activity. Kinetic analyses demonstrated a loss of catalysis rather than diminished substrate binding. These data suggest that loss of lipin 1-mediated PAP activity may be involved in the pathogenesis of rhabdomyolysis in lipin 1 deficiency.
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232
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Vig S, Talwar P, Kaur K, Srivastava R, Srivastava AK, Datta M. Transcriptome profiling identifies p53 as a key player during calreticulin deficiency: Implications in lipid accumulation. Cell Cycle 2015; 14:2274-84. [PMID: 25946468 DOI: 10.1080/15384101.2015.1046654] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Calreticulin (CRT) is an endoplasmic reticulum (ER) resident calcium binding protein that is involved in several cellular activities. Transcriptome analyses in CRT knockdown HepG2 cells revealed 253 altered unique genes and subsequent in silico protein-protein interaction network and MCODE clustering identified 34 significant clusters, of which p53 occupied the central hub node in the highest node-rich cluster. Toward validation, we show that CRT knockdown leads to inhibition of p53 protein levels. Both, CRT and p53 siRNA promote hepatic lipid accumulation and this was accompanied by elevated SREBP-1c and FAS levels. p53 was identified to bind at -219 bp on the SREBP-1c promoter and in the presence of CRT siRNA, there was decreased occupancy of p53 on this binding element. This was associated with increased SREBP-1c promoter activity and both, mutation in this binding site or p53 over-expression antagonised the effects of CRT knockdown. We, therefore, identify a negatively regulating p53 binding site on the SREBP-1c promoter that is critical during hepatic lipid accumulation. These results were validated in mouse primary hepatocytes and toward a physiological relevance, we report that while the levels of CRT and p53 are reduced in the fatty livers of diabetic db/db mice, SREBP-1c levels are significantly elevated. Our results suggest that decreased CRT levels might be involved in the development of a fatty liver by preventing p53 occupancy on the SREBP-1c promoter and thereby facilitating SREBP-1c up-regulation and consequently, lipid accumulation.
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Affiliation(s)
- Saurabh Vig
- a CSIR-Institute of Genomics and Integrative Biology ; Delhi , India
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233
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Kinetics of lipogenic genes expression in milk purified mammary epithelial cells (MEC) across lactation and their correlation with milk and fat yield in buffalo. Res Vet Sci 2015; 99:129-36. [DOI: 10.1016/j.rvsc.2015.01.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Revised: 01/05/2015] [Accepted: 01/10/2015] [Indexed: 01/16/2023]
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234
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Craddock CP, Adams N, Bryant FM, Kurup S, Eastmond PJ. PHOSPHATIDIC ACID PHOSPHOHYDROLASE Regulates Phosphatidylcholine Biosynthesis in Arabidopsis by Phosphatidic Acid-Mediated Activation of CTP:PHOSPHOCHOLINE CYTIDYLYLTRANSFERASE Activity. THE PLANT CELL 2015; 27:1251-64. [PMID: 25862304 PMCID: PMC4558698 DOI: 10.1105/tpc.15.00037] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 03/19/2015] [Indexed: 05/04/2023]
Abstract
Regulation of membrane lipid biosynthesis is critical for cell function. We previously reported that disruption of PHOSPHATIDIC ACID PHOSPHOHYDROLASE1 (PAH1) and PAH2 stimulates net phosphatidylcholine (PC) biosynthesis and proliferation of the endoplasmic reticulum (ER) in Arabidopsis thaliana. Here, we show that this response is caused specifically by a reduction in the catalytic activity of the protein and positively correlates with an accumulation of its substrate, phosphatidic acid (PA). The accumulation of PC in pah1 pah2 is suppressed by disruption of CTP:PHOSPHOCHOLINE CYTIDYLYLTRANSFERASE1 (CCT1), which encodes a key enzyme in the nucleotide pathway for PC biosynthesis. The activity of recombinant CCT1 is stimulated by lipid vesicles containing PA. Truncation of CCT1, to remove the predicted C-terminal amphipathic lipid binding domain, produced a constitutively active enzyme. Overexpression of native CCT1 in Arabidopsis has no significant effect on PC biosynthesis or ER morphology, but overexpression of the truncated constitutively active version largely replicates the pah1 pah2 phenotype. Our data establish that membrane homeostasis is regulated by lipid composition in Arabidopsis and reveal a mechanism through which the abundance of PA, mediated by PAH activity, modulates CCT activity to govern PC content.
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Affiliation(s)
- Christian P Craddock
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Nicolette Adams
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Fiona M Bryant
- Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom
| | - Smita Kurup
- Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom
| | - Peter J Eastmond
- Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom
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235
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Rojas JM, Bruinstroop E, Printz RL, Alijagic-Boers A, Foppen E, Turney MK, George L, Beck-Sickinger AG, Kalsbeek A, Niswender KD. Central nervous system neuropeptide Y regulates mediators of hepatic phospholipid remodeling and very low-density lipoprotein triglyceride secretion via sympathetic innervation. Mol Metab 2015; 4:210-21. [PMID: 25737956 PMCID: PMC4338317 DOI: 10.1016/j.molmet.2015.01.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 12/29/2014] [Accepted: 01/09/2015] [Indexed: 12/26/2022] Open
Abstract
OBJECTIVE Elevated very low-density lipoprotein (VLDL)-triglyceride (TG) secretion from the liver contributes to an atherogenic dyslipidemia that is associated with obesity, diabetes and the metabolic syndrome. Numerous models of obesity and diabetes are characterized by increased central nervous system (CNS) neuropeptide Y (NPY); in fact, a single intracerebroventricular (icv) administration of NPY in lean fasted rats elevates hepatic VLDL-TG secretion and does so, in large part, via signaling through the CNS NPY Y1 receptor. Thus, our overarching hypothesis is that elevated CNS NPY action contributes to dyslipidemia by activating central circuits that modulate liver lipid metabolism. METHODS Chow-fed Zucker fatty (ZF) rats were pair-fed by matching their caloric intake to that of lean controls and effects on body weight, plasma TG, and liver content of TG and phospholipid (PL) were compared to ad-libitum (ad-lib) fed ZF rats. Additionally, lean 4-h fasted rats with intact or disrupted hepatic sympathetic innervation were treated with icv NPY or NPY Y1 receptor agonist to identify novel hepatic mechanisms by which NPY promotes VLDL particle maturation and secretion. RESULTS Manipulation of plasma TG levels in obese ZF rats, through pair-feeding had no effect on liver TG content; however, hepatic PL content was substantially reduced and was tightly correlated with plasma TG levels. Treatment with icv NPY or a selective NPY Y1 receptor agonist in lean fasted rats robustly activated key hepatic regulatory proteins, stearoyl-CoA desaturase-1 (SCD-1), ADP-ribosylation factor-1 (ARF-1), and lipin-1, known to be involved in remodeling liver PL into TG for VLDL maturation and secretion. Lastly, we show that the effects of CNS NPY on key liporegulatory proteins are attenuated by hepatic sympathetic denervation. CONCLUSIONS These data support a model in which CNS NPY modulates mediators of hepatic PL remodeling and VLDL maturation to stimulate VLDL-TG secretion that is dependent on the Y1 receptor and sympathetic signaling to the liver.
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Key Words
- AGPAT, 1-acyl-glycerol-3-phosphate acyltransferase
- ARF-1, ADP-ribosylation factor-1
- ApoB, apolipoprotein B
- CNS, central nervous system
- Cyto, cytoplasmic
- DAG, diacylglycerol
- DGAT, diacylglycerol acyltransferase
- ER, endoplasmic reticulum
- FFA(s), free fatty acid(s)
- GAPDH, glyceraldehyde 3-phosphate dehydrogenase
- HDAC-1, histone deacetylase-1
- Lipin-1
- NE, norepinephrine
- NPY Y1 receptor
- NPY, neuropeptide Y
- Nuc, nuclear
- PA, phosphatidic acid
- PAP-1, phosphatidic acid phosphatase-1
- PF, pair-fed
- PL, phospholipid
- PLD, phospholipase D
- POMC, proopiomelanocortin
- Phospholipid
- RPL13A, ribosomal protein L13a
- RT-PCR, real-time PCR
- SCD-1, stearoyl-CoA desaturase-1
- SNS, sympathetic nervous system
- Sham, sham-denervation
- Sx, sympathetic denervation
- Sympathetic denervation
- TG, triglyceride
- Triglyceride
- VLDL
- VLDL, very low-density lipoprotein
- Veh, vehicle
- ZF, Zucker fatty
- ad-lib, ad-libitum
- icv, intracerebroventricular
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Affiliation(s)
- Jennifer M. Rojas
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Eveline Bruinstroop
- Department of Endocrinology and Metabolism, Laboratory of Endocrinology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Richard L. Printz
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Aldijana Alijagic-Boers
- Department of Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Science, Amsterdam, The Netherlands
| | - Ewout Foppen
- Department of Endocrinology and Metabolism, Laboratory of Endocrinology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Maxine K. Turney
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Leena George
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Annette G. Beck-Sickinger
- Institute of Biochemistry, Faculty of Bioscience, Pharmacy and Psychology, Leipzig University, Leipzig, Germany
| | - Andries Kalsbeek
- Department of Endocrinology and Metabolism, Laboratory of Endocrinology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Department of Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Science, Amsterdam, The Netherlands
| | - Kevin D. Niswender
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, United States
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, United States
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, United States
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236
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Schweitzer GG, Chen Z, Gan C, McCommis KS, Soufi N, Chrast R, Mitra MS, Yang K, Gross RW, Finck BN. Liver-specific loss of lipin-1-mediated phosphatidic acid phosphatase activity does not mitigate intrahepatic TG accumulation in mice. J Lipid Res 2015; 56:848-58. [PMID: 25722343 DOI: 10.1194/jlr.m055962] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Lipin proteins (lipin 1, 2, and 3) regulate glycerolipid homeostasis by acting as phosphatidic acid phosphohydrolase (PAP) enzymes in the TG synthesis pathway and by regulating DNA-bound transcription factors to control gene transcription. Hepatic PAP activity could contribute to hepatic fat accumulation in response to physiological and pathophysiological stimuli. To examine the role of lipin 1 in regulating hepatic lipid metabolism, we generated mice that are deficient in lipin-1-encoded PAP activity in a liver-specific manner (Alb-Lpin1(-/-) mice). This allele of lipin 1 was still able to transcriptionally regulate the expression of its target genes encoding fatty acid oxidation enzymes, and the expression of these genes was not affected in Alb-Lpin1(-/-) mouse liver. Hepatic PAP activity was significantly reduced in mice with liver-specific lipin 1 deficiency. However, hepatocytes from Alb-Lpin1(-/-) mice had normal rates of TG synthesis, and steady-state hepatic TG levels were unaffected under fed and fasted conditions. Furthermore, Alb-Lpin1(-/-) mice were not protected from intrahepatic accumulation of diacylglycerol and TG after chronic feeding of a diet rich in fat and fructose. Collectively, these data demonstrate that marked deficits in hepatic PAP activity do not impair TG synthesis and accumulation under acute or chronic conditions of lipid overload.
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Affiliation(s)
| | - Zhouji Chen
- Washington University School of Medicine, St. Louis, MO 63110
| | - Connie Gan
- Washington University School of Medicine, St. Louis, MO 63110
| | - Kyle S McCommis
- Washington University School of Medicine, St. Louis, MO 63110
| | - Nisreen Soufi
- Washington University School of Medicine, St. Louis, MO 63110
| | - Roman Chrast
- Department of Medical Genetics, University of Lausanne, 1005 Lausanne, Switzerland
| | | | - Kui Yang
- Washington University School of Medicine, St. Louis, MO 63110
| | - Richard W Gross
- Washington University School of Medicine, St. Louis, MO 63110
| | - Brian N Finck
- Washington University School of Medicine, St. Louis, MO 63110
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237
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iASPP, a previously unidentified regulator of desmosomes, prevents arrhythmogenic right ventricular cardiomyopathy (ARVC)-induced sudden death. Proc Natl Acad Sci U S A 2015; 112:E973-81. [PMID: 25691752 DOI: 10.1073/pnas.1408111112] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Desmosomes are anchoring junctions that exist in cells that endure physical stress such as cardiac myocytes. The importance of desmosomes in maintaining the homeostasis of the myocardium is underscored by frequent mutations of desmosome components found in human patients and animal models. Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a phenotype caused by mutations in desmosomal components in ∼ 50% of patients, however, the causes in the remaining 50% of patients still remain unknown. A deficiency of inhibitor of apoptosis-stimulating protein of p53 (iASPP), an evolutionarily conserved inhibitor of p53, caused by spontaneous mutation recently has been associated with a lethal autosomal recessive cardiomyopathy in Poll Hereford calves and Wa3 mice. However, the molecular mechanisms that mediate this putative function of iASPP are completely unknown. Here, we show that iASPP is expressed at intercalated discs in human and mouse postmitotic cardiomyocytes. iASPP interacts with desmoplakin and desmin in cardiomyocytes to maintain the integrity of desmosomes and intermediate filament networks in vitro and in vivo. iASPP deficiency specifically induces right ventricular dilatation in mouse embryos at embryonic day 16.5. iASPP-deficient mice with exon 8 deletion (Ppp1r13l(Δ8/Δ8)) die of sudden cardiac death, displaying features of ARVC. Intercalated discs in cardiomyocytes from four of six human ARVC cases show reduced or loss of iASPP. ARVC-derived desmoplakin mutants DSP-1-V30M and DSP-1-S299R exhibit weaker binding to iASPP. These data demonstrate that by interacting with desmoplakin and desmin, iASPP is an important regulator of desmosomal function both in vitro and in vivo. This newly identified property of iASPP may provide new molecular insight into the pathogenesis of ARVC.
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238
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Bi L, Jiang Z, Zhou J. The role of lipin-1 in the pathogenesis of alcoholic fatty liver. Alcohol Alcohol 2015; 50:146-51. [PMID: 25595739 DOI: 10.1093/alcalc/agu102] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
AIMS The aim of this review was to focus on the knowledge of the role of lipin-1 in the pathogenesis of alcoholic fatty liver. METHODS Systematic review of animal clinical and cell level studies related to the function of lipin-1 on alcoholic fatty liver, alcoholic hepatitis and alcoholic liver cirrhosis disease. RESULT Ethanol could increase the expression of lipin-1 through the AMPK-SREBP-1 signaling and dramatically increase the ratio of Lpin1β to Lpin1α by SIRT1-SFRS10-Lpin1β/α axis in the liver. Moreover, research has shown that over-expression of lipin-1 could also remarkably suppress very low density lipoprotein-triacylglyceride secretion. Last, lipin-1 has potent anti-inflammatory property. CONCLUSION In conclusion, lipin-1 has dual functions in lipid metabolism. In the cytoplasm, lipin-1β functions as a Mg(2+)-dependent phosphatidic acid phosphohydrolase (PAP) enzyme in triglyceride synthesis pathways. In the nucleus, lipin-1α acts as a transcriptional co-regulator to regulate the capacity of the liver for fatty acid oxidation and activity of the lipogenic enzyme. In hepatocytes of alcoholic fatty liver disease (AFLD), ethanol increases the expression of lipin-1 through the AMPK-SREBP-1 signaling and the Lpin1β/α ratio by SIRT1-SFRS10- Lpin1β/α axis. Of course, in addition to that, ethanol could also produce the PAP activity and interrupt the nucleus function of lipin-1. Furthermore, over-expression of lipin-1 could remarkably suppress very low-density lipoprotein-triacylglyceride (VLDL-TAG) secretion. In the end, endogenous lipin-1 has potent anti-inflammatory property. Increased synthesis of TAG, decreased fatty acid oxidation, impaired VLDL-TAG secretion and activated inflammatory factors act together to exacerbate the development of AFLD.
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Affiliation(s)
- Lijuan Bi
- Department of Infectious Disease, Third Hospital, Hebei Medical University, 139 ZiQiang Road, Shijiazhuang 050051, China
| | - Zhian Jiang
- Department of Infectious Disease, Third Hospital, Hebei Medical University, 139 ZiQiang Road, Shijiazhuang 050051, China
| | - Junying Zhou
- Department of Infectious Disease, Third Hospital, Hebei Medical University, 139 ZiQiang Road, Shijiazhuang 050051, China
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239
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Lee YJ, Choi HS, Seo MJ, Jeon HJ, Kim KJ, Lee BY. Kaempferol suppresses lipid accumulation by inhibiting early adipogenesis in 3T3-L1 cells and zebrafish. Food Funct 2015; 6:2824-33. [DOI: 10.1039/c5fo00481k] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Kaempferol is a flavonoid present in Kaempferia galanga and Opuntia ficus indica var. saboten.
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Affiliation(s)
- Yeon-Joo Lee
- Department of Food Science and Biotechnology
- CHA University
- Seongnam
- South Korea
| | - Hyeon-Son Choi
- Department of Food Science and Technology
- Seoul Women's University
- Seoul
- Korea
| | - Min-Jung Seo
- Department of Food Science and Biotechnology
- CHA University
- Seongnam
- South Korea
| | - Hui-Jeon Jeon
- Department of Food Science and Biotechnology
- CHA University
- Seongnam
- South Korea
| | - Kui-Jin Kim
- Department of Medicine
- Laboratory for Lipid Medicine & Technology
- Harvard Medical School Massachusetts General Hospital
- Charlestown
- USA
| | - Boo-Yong Lee
- Department of Food Science and Biotechnology
- CHA University
- Seongnam
- South Korea
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240
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Sun C, Wang M, Liu X, Luo L, Li K, Zhang S, Wang Y, Yang Y, Ding F, Gu X. PCAF improves glucose homeostasis by suppressing the gluconeogenic activity of PGC-1α. Cell Rep 2014; 9:2250-62. [PMID: 25497092 DOI: 10.1016/j.celrep.2014.11.029] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Revised: 10/28/2014] [Accepted: 11/19/2014] [Indexed: 12/22/2022] Open
Abstract
PGC-1α plays a central role in hepatic gluconeogenesis and has been implicated in the onset of type 2 diabetes. Acetylation is an important posttranslational modification for regulating the transcriptional activity of PGC-1α. Here, we show that PCAF is a pivotal acetyltransferase for acetylating PGC-1α in both fasted and diabetic states. PCAF acetylates two lysine residues K328 and K450 in PGC-1α, which subsequently triggers its proteasomal degradation and suppresses its transcriptional activity. Adenoviral-mediated expression of PCAF in the obese mouse liver greatly represses gluconeogenic enzyme activation and glucose production and improves glucose homeostasis and insulin sensitivity. Moreover, liver-specific knockdown of PCAF stimulates PGC-1α activity, resulting in an increase in blood glucose and hepatic glucose output. Our results suggest that PCAF might be a potential pharmacological target for developing agents against metabolic disorders associated with hyperglycemia, such as obesity and diabetes.
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Affiliation(s)
- Cheng Sun
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, 19 Qixiu Road, Nantong, Jiangsu 226001, PRC; Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, PRC.
| | - Meihong Wang
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, 19 Qixiu Road, Nantong, Jiangsu 226001, PRC; Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, PRC
| | - Xiaoyu Liu
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, 19 Qixiu Road, Nantong, Jiangsu 226001, PRC; Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, PRC
| | - Lan Luo
- Department of Geratology, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, PRC
| | - Kaixuan Li
- Department of Geratology, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, PRC
| | - Shuqiang Zhang
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, 19 Qixiu Road, Nantong, Jiangsu 226001, PRC; Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, PRC
| | - Yongjun Wang
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, 19 Qixiu Road, Nantong, Jiangsu 226001, PRC; Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, PRC
| | - Yumin Yang
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, 19 Qixiu Road, Nantong, Jiangsu 226001, PRC; Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, PRC
| | - Fei Ding
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, 19 Qixiu Road, Nantong, Jiangsu 226001, PRC; Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, PRC
| | - Xiaosong Gu
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, 19 Qixiu Road, Nantong, Jiangsu 226001, PRC; Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, PRC.
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241
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Abstract
The liver is an essential metabolic organ, and its metabolic function is controlled by insulin and other metabolic hormones. Glucose is converted into pyruvate through glycolysis in the cytoplasm, and pyruvate is subsequently oxidized in the mitochondria to generate ATP through the TCA cycle and oxidative phosphorylation. In the fed state, glycolytic products are used to synthesize fatty acids through de novo lipogenesis. Long-chain fatty acids are incorporated into triacylglycerol, phospholipids, and/or cholesterol esters in hepatocytes. These complex lipids are stored in lipid droplets and membrane structures, or secreted into the circulation as very low-density lipoprotein particles. In the fasted state, the liver secretes glucose through both glycogenolysis and gluconeogenesis. During pronged fasting, hepatic gluconeogenesis is the primary source for endogenous glucose production. Fasting also promotes lipolysis in adipose tissue, resulting in release of nonesterified fatty acids which are converted into ketone bodies in hepatic mitochondria though β-oxidation and ketogenesis. Ketone bodies provide a metabolic fuel for extrahepatic tissues. Liver energy metabolism is tightly regulated by neuronal and hormonal signals. The sympathetic system stimulates, whereas the parasympathetic system suppresses, hepatic gluconeogenesis. Insulin stimulates glycolysis and lipogenesis but suppresses gluconeogenesis, and glucagon counteracts insulin action. Numerous transcription factors and coactivators, including CREB, FOXO1, ChREBP, SREBP, PGC-1α, and CRTC2, control the expression of the enzymes which catalyze key steps of metabolic pathways, thus controlling liver energy metabolism. Aberrant energy metabolism in the liver promotes insulin resistance, diabetes, and nonalcoholic fatty liver diseases.
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Affiliation(s)
- Liangyou Rui
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan
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242
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Chen Y, Rui BB, Tang LY, Hu CM. Lipin Family Proteins - Key Regulators in Lipid Metabolism. ANNALS OF NUTRITION AND METABOLISM 2014; 66:10-8. [DOI: 10.1159/000368661] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 09/19/2014] [Indexed: 11/19/2022]
Abstract
Background: Proteins in the lipin family play a key role in lipid synthesis due to their phosphatidate phosphatase activity, and they also act as transcriptional coactivators to regulate the expression of genes involved in lipid metabolism. The lipin family includes three members, lipin1, lipin2, and lipin3, which exhibit tissue-specific expression, indicating that they may have distinct roles in mediating disease. To date, most studies have focused on lipin1, whereas the roles of lipin2 and lipin3 are less understood. Summary: This review introduces the structural characteristics, physiological functions, relationship to lipid metabolism, and patterns of expression of the lipin family proteins, highlighting their roles in lipid metabolic homeostasis. © 2014 S. Karger AG, Basel
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243
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Glucocorticoids promote structural and functional maturation of foetal cardiomyocytes: a role for PGC-1α. Cell Death Differ 2014; 22:1106-16. [PMID: 25361084 PMCID: PMC4572859 DOI: 10.1038/cdd.2014.181] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 09/08/2014] [Accepted: 09/22/2014] [Indexed: 01/05/2023] Open
Abstract
Glucocorticoid levels rise dramatically in late gestation to mature foetal organs in readiness for postnatal life. Immature heart function may compromise survival. Cardiomyocyte glucocorticoid receptor (GR) is required for the structural and functional maturation of the foetal heart in vivo, yet the molecular mechanisms are largely unknown. Here we asked if GR activation in foetal cardiomyocytes in vitro elicits similar maturational changes. We show that physiologically relevant glucocorticoid levels improve contractility of primary-mouse-foetal cardiomyocytes, promote Z-disc assembly and the appearance of mature myofibrils, and increase mitochondrial activity. Genes induced in vitro mimic those induced in vivo and include PGC-1α, a critical regulator of cardiac mitochondrial capacity. SiRNA-mediated abrogation of the glucocorticoid induction of PGC-1α in vitro abolished the effect of glucocorticoid on myofibril structure and mitochondrial oxygen consumption. Using RNA sequencing we identified a number of transcriptional regulators, including PGC-1α, induced as primary targets of GR in foetal cardiomyocytes. These data demonstrate that PGC-1α is a key mediator of glucocorticoid-induced maturation of foetal cardiomyocyte structure and identify other candidate transcriptional regulators that may play critical roles in the transition of the foetal to neonatal heart.
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244
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Yokota SI, Nakamura K, Ando M, Kamei H, Hakuno F, Takahashi SI, Shibata S. Acetylcholinesterase (AChE) inhibition aggravates fasting-induced triglyceride accumulation in the mouse liver. FEBS Open Bio 2014; 4:905-14. [PMID: 25383314 PMCID: PMC4223152 DOI: 10.1016/j.fob.2014.10.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 10/13/2014] [Accepted: 10/16/2014] [Indexed: 12/11/2022] Open
Abstract
Although fasting induces hepatic triglyceride (TG) accumulation in both rodents and humans, little is known about the underlying mechanism. Because parasympathetic nervous system activity tends to attenuate the secretion of very-low-density-lipoprotein-triglyceride (VLDL-TG) and increase TG stores in the liver, and serum cholinesterase activity is elevated in fatty liver disease, the inhibition of the parasympathetic neurotransmitter acetylcholinesterase (AChE) may have some influence on hepatic lipid metabolism. To assess the influence of AChE inhibition on lipid metabolism, the effect of physostigmine, an AChE inhibitor, on fasting-induced increase in liver TG was investigated in mice. In comparison with ad libitum-fed mice, 30 h fasting increased liver TG accumulation accompanied by a downregulation of sterol regulatory element-binding protein 1 (SREBP-1) and liver-fatty acid binding-protein (L-FABP). Physostigmine promoted the 30 h fasting-induced increase in liver TG levels in a dose-dependent manner, accompanied by a significant fall in plasma insulin levels, without a fall in plasma TG. Furthermore, physostigmine significantly attenuated the fasting-induced decrease of both mRNA and protein levels of SREBP-1 and L-FABP, and increased IRS-2 protein levels in the liver. The muscarinic receptor antagonist atropine blocked these effects of physostigmine on liver TG, serum insulin, and hepatic protein levels of SREBP-1 and L-FABP. These results demonstrate that AChE inhibition facilitated fasting-induced TG accumulation with up regulation of the hepatic L-FABP and SREBP-1 in mice, at least in part via the activation of muscarinic acetylcholine receptors. Our studies highlight the crucial role of parasympathetic regulation in fasting-induced TG accumulation, and may be an important source of information on the mechanism of hepatic disorders of lipid metabolism.
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Key Words
- ACC, acetyl coenzyme-A carboxylase
- ACh, acetylcholine
- AChE, acetylcholinesterase
- CPT-1, carnitine palmitoyltransferase 1
- FA, fatty acid(s)
- FAS, fatty acid synthase
- Fatty liver
- IRS-2, insulin receptor substrate
- L-FABP, liver fatty acid-binding protein
- Lipogenesis
- Lipolysis
- Metabolic syndrome
- PEPCK, phosphoenolpyruvate carboxykinase
- PGC-1α, peroxisome proliferator activated receptor gamma coactivator 1-alpha
- PPAR-α, peroxisome proliferator activated receptor alpha
- Parasympathetic nerve
- SREBP, sterol regulatory element binding proteins
- TG, triglyceride(s)
- Triglyceride
- VLDL, very low-density lipoprotein(s)
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Affiliation(s)
- Shin-Ichi Yokota
- Department of Physiology and Pharmacology, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan ; Consolidated Research Institute for Advanced Science and Medical Care, Waseda University, Tokyo, Japan
| | - Kaai Nakamura
- Department of Physiology and Pharmacology, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Midori Ando
- Department of Physiology and Pharmacology, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Hiroyasu Kamei
- Department of Animal Sciences and Applied Biological Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Fumihiko Hakuno
- Department of Animal Sciences and Applied Biological Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Shin-Ichiro Takahashi
- Department of Animal Sciences and Applied Biological Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Shigenobu Shibata
- Department of Physiology and Pharmacology, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
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245
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Kebede MA, Attie AD. Insights into obesity and diabetes at the intersection of mouse and human genetics. Trends Endocrinol Metab 2014; 25:493-501. [PMID: 25034129 PMCID: PMC4177963 DOI: 10.1016/j.tem.2014.06.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Revised: 06/06/2014] [Accepted: 06/06/2014] [Indexed: 11/25/2022]
Abstract
Many of our insights into obesity and diabetes come from studies in mice carrying natural or induced mutations. In parallel, genome-wide association studies (GWAS) in humans have identified numerous genes that are causally associated with obesity and diabetes, but discovering the underlying mechanisms required in-depth studies in mice. We discuss the advantages of studying natural variation in mice and summarize several examples where the combination of human and mouse genetics opened windows into fundamental physiological pathways. A noteworthy example is the melanocortin-4 receptor (MC4R) and its role in energy balance. The pathway was delineated by discovering the gene responsible for the Agouti mutation in mice. With more targeted phenotyping, we predict that additional pathways relevant to human pathophysiology will be discovered.
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Affiliation(s)
- Melkam A Kebede
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Alan D Attie
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA.
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246
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Williams JA, Manley S, Ding WX. New advances in molecular mechanisms and emerging therapeutic targets in alcoholic liver diseases. World J Gastroenterol 2014; 20:12908-12933. [PMID: 25278688 PMCID: PMC4177473 DOI: 10.3748/wjg.v20.i36.12908] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 03/07/2014] [Accepted: 04/16/2014] [Indexed: 02/06/2023] Open
Abstract
Alcoholic liver disease is a major health problem in the United States and worldwide. Chronic alcohol consumption can cause steatosis, inflammation, fibrosis, cirrhosis and even liver cancer. Significant progress has been made to understand key events and molecular players for the onset and progression of alcoholic liver disease from both experimental and clinical alcohol studies. No successful treatments are currently available for treating alcoholic liver disease; therefore, development of novel pathophysiological-targeted therapies is urgently needed. This review summarizes the recent progress on animal models used to study alcoholic liver disease and the detrimental factors that contribute to alcoholic liver disease pathogenesis including miRNAs, S-adenosylmethionine, Zinc deficiency, cytosolic lipin-1β, IRF3-mediated apoptosis, RIP3-mediated necrosis and hepcidin. In addition, we summarize emerging adaptive protective effects induced by alcohol to attenuate alcohol-induced liver pathogenesis including FoxO3, IL-22, autophagy and nuclear lipin-1α.
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247
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Cao PJ, Jin YJ, Li ME, Zhou R, Yang MZ. PGC-1α may associated with the anti-obesity effect of taurine on rats induced by arcuate nucleus lesion. Nutr Neurosci 2014; 19:86-93. [DOI: 10.1179/1476830514y.0000000153] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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248
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da Silva RP, Kelly KB, Leonard KA, Jacobs RL. Creatine reduces hepatic TG accumulation in hepatocytes by stimulating fatty acid oxidation. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:1639-46. [PMID: 25205520 DOI: 10.1016/j.bbalip.2014.09.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 08/15/2014] [Accepted: 09/02/2014] [Indexed: 12/22/2022]
Abstract
Non-alcoholic fatty liver disease encompasses a wide spectrum of liver damage including steatosis, non-alcoholic steatohepatitis, fibrosis and cirrhosis. We have previously reported that creatine supplementation prevents hepatic steatosis and lipid peroxidation in rats fed a high-fat diet. In this study, we employed oleate-treated McArdle RH-7777 rat hepatoma cells to investigate the role of creatine in regulating hepatic lipid metabolism. Creatine, but not structural analogs, reduced cellular TG accumulation in a dose-dependent manner. Incubating cells with the pan-lipase inhibitor diethyl p-nitrophenylphosphate (E600) did not diminish the effect of creatine, demonstrating that the TG reduction brought about by creatine does not depend on lipolysis. Radiolabeled tracer experiments indicate that creatine increases fatty acid oxidation and TG secretion. In line with increased fatty acid oxidation, mRNA analysis revealed that creatine-treated cells had increased expression of PPARα and several of its transcriptional targets. Taken together, this study provides direct evidence that creatine reduces lipid accumulation in hepatocytes by the stimulation of fatty acid oxidation and TG secretion.
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Affiliation(s)
- Robin P da Silva
- Metabolic and Cardiovascular Diseases Laboratory, Group on the Molecular and Cell Biology of Lipids, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Karen B Kelly
- Metabolic and Cardiovascular Diseases Laboratory, Group on the Molecular and Cell Biology of Lipids, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Kelly-Ann Leonard
- Metabolic and Cardiovascular Diseases Laboratory, Group on the Molecular and Cell Biology of Lipids, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - René L Jacobs
- Metabolic and Cardiovascular Diseases Laboratory, Group on the Molecular and Cell Biology of Lipids, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada.
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249
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Zhang P, Verity MA, Reue K. Lipin-1 regulates autophagy clearance and intersects with statin drug effects in skeletal muscle. Cell Metab 2014; 20:267-79. [PMID: 24930972 PMCID: PMC4170588 DOI: 10.1016/j.cmet.2014.05.003] [Citation(s) in RCA: 121] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 03/03/2014] [Accepted: 04/21/2014] [Indexed: 02/04/2023]
Abstract
LPIN1 encodes lipin-1, a phosphatidic acid phosphatase (PAP) enzyme that catalyzes the dephosphorylation of phosphatidic acid to form diacylglycerol. Homozygous LPIN1 gene mutations cause severe rhabdomyolysis, and heterozygous LPIN1 missense mutations may promote statin-induced myopathy. We demonstrate that lipin-1-related myopathy in the mouse is associated with a blockade in autophagic flux and accumulation of aberrant mitochondria. Lipin-1 PAP activity is required for maturation of autolysosomes, through its activation of the protein kinase D (PKD)-Vps34 phosphatidylinositol 3-kinase signaling cascade. Statin treatment also reduces PKD activation and autophagic flux, which are compounded by diminished mammalian target of rapamycin (mTOR) abundance in lipin-1-haploinsufficent and -deficient muscle. Lipin-1 restoration in skeletal muscle prevents myonecrosis and statin toxicity in vivo, and activated PKD rescues autophagic flux in lipin-1-deficient cells. Our findings identify lipin-1 PAP activity as a component of the macroautophagy pathway and define the basis for lipin-1-related myopathies.
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Affiliation(s)
- Peixiang Zhang
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - M Anthony Verity
- Division of Neuropathology, Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Karen Reue
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA; Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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250
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Settembre C, Ballabio A. Lysosome: regulator of lipid degradation pathways. Trends Cell Biol 2014; 24:743-50. [PMID: 25061009 PMCID: PMC4247383 DOI: 10.1016/j.tcb.2014.06.006] [Citation(s) in RCA: 147] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 06/24/2014] [Accepted: 06/25/2014] [Indexed: 02/05/2023]
Abstract
Lipophagy is a transcriptionally regulated process. The lysosome as a sensor of lipophagy induction. Nuclear receptors link lipophagy to lipid catabolism.
Autophagy is a catabolic pathway that has a fundamental role in the adaptation to fasting and primarily relies on the activity of the endolysosomal system, to which the autophagosome targets substrates for degradation. Recent studies have revealed that the lysosomal–autophagic pathway plays an important part in the early steps of lipid degradation. In this review, we discuss the transcriptional mechanisms underlying co-regulation between lysosome, autophagy, and other steps of lipid catabolism, including the activity of nutrient-sensitive transcription factors (TFs) and of members of the nuclear receptor family. In addition, we discuss how the lysosome acts as a metabolic sensor and orchestrates the transcriptional response to fasting.
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Affiliation(s)
- Carmine Settembre
- Dulbecco Telethon Institute, Via Pietro Castellino 111, 80131, Naples, Italy; Telethon Institute of Genetics and Medicine (TIGEM), Via Pietro Castellino 111, 80131, Naples, Italy; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA; Medical Genetics, Department of Translational and Medical Science, Federico II University, Via Pansini 5, 80131 Naples, Italy.
| | - Andrea Ballabio
- Telethon Institute of Genetics and Medicine (TIGEM), Via Pietro Castellino 111, 80131, Naples, Italy; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA; Medical Genetics, Department of Translational and Medical Science, Federico II University, Via Pansini 5, 80131 Naples, Italy.
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