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Liu C, Lin Y, Wang Y, Lin S, Zhou J, Tang H, Yi X, Ma Z, Xia T, Jiang B, Tian F, Ju Z, Liu B, Gu X, Yang Z, Wang W. HuR promotes triglyceride synthesis and intestinal fat absorption. Cell Rep 2024; 43:114238. [PMID: 38748875 DOI: 10.1016/j.celrep.2024.114238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Revised: 04/02/2024] [Accepted: 04/30/2024] [Indexed: 06/01/2024] Open
Abstract
Triacylglyceride (TAG) synthesis in the small intestine determines the absorption of dietary fat, but the underlying mechanisms remain to be further studied. Here, we report that the RNA-binding protein HuR (ELAVL1) promotes TAG synthesis in the small intestine. HuR associates with the 3' UTR of Dgat2 mRNA and intron 1 of Mgat2 pre-mRNA. Association of HuR with Dgat2 3' UTR stabilizes Dgat2 mRNA, while association of HuR with intron 1 of Mgat2 pre-mRNA promotes the processing of Mgat2 pre-mRNA. Intestinal epithelium-specific HuR knockout reduces the expression of DGAT2 and MGAT2, thereby reducing the dietary fat absorption through TAG synthesis and mitigating high-fat-diet (HFD)-induced non-alcoholic fatty liver disease (NAFLD) and obesity. Our findings highlight a critical role of HuR in promoting dietary fat absorption.
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Affiliation(s)
- Cihang Liu
- Department of Anesthesiology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing 210008, China; Department of Biochemistry and Molecular Biology, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, School of Basic Medical Sciences, Peking University Health Science Center, 38 Xueyuan Road, Beijing 100191, China
| | - Yunping Lin
- Department of Biochemistry and Molecular Biology, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, School of Basic Medical Sciences, Peking University Health Science Center, 38 Xueyuan Road, Beijing 100191, China
| | - Ying Wang
- Department of Biochemistry and Molecular Biology, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, School of Basic Medical Sciences, Peking University Health Science Center, 38 Xueyuan Road, Beijing 100191, China
| | - Shuyong Lin
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Jing Zhou
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Hao Tang
- National Health Commission Key Laboratory of Cardiovascular Regenerative Medicine, Heart Center of Henan Provincial People's Hospital, Central China Fuwai Hospital of Zhengzhou University, Central China Fuwai Hospital and Central China Branch of National Center for Cardiovascular Diseases, Zhengzhou, Henan 450003, China
| | - Xia Yi
- Department of Biochemistry and Molecular Biology, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, School of Basic Medical Sciences, Peking University Health Science Center, 38 Xueyuan Road, Beijing 100191, China
| | - Zhengliang Ma
- Department of Anesthesiology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing 210008, China
| | - Tianjiao Xia
- Medical School, Nanjing University, Nanjing 210093, China
| | - Bin Jiang
- Department of Biochemistry and Molecular Biology, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, School of Basic Medical Sciences, Peking University Health Science Center, 38 Xueyuan Road, Beijing 100191, China
| | - Feng Tian
- Department of Laboratory Animal Science, Peking University Health Science Center, 38 Xueyuan Road, Beijing 100191, China
| | - Zhenyu Ju
- Key Laboratory of Regenerative Medicine of Ministry of Education, Institute of Aging and Regenerative Medicine, Jinan University, Guangzhou 510632, China
| | - Baohua Liu
- Guangdong Key Laboratory of Genome Stability and Human Disease Prevention, Carson International Cancer Center, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Shenzhen University Health Science Center, Shenzhen 518060, China
| | - Xiaoping Gu
- Department of Anesthesiology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing 210008, China.
| | - Zhongzhou Yang
- Medical School, Nanjing University, Nanjing 210093, China.
| | - Wengong Wang
- Department of Biochemistry and Molecular Biology, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, School of Basic Medical Sciences, Peking University Health Science Center, 38 Xueyuan Road, Beijing 100191, China; Center for Healthy Aging, Changzhi Medical College, Changzhi 046000, China; Liaoning Technology and Engineering Center for Tumor Immunology and Molecular Theranostics, Collaborative Innovation Center for Age-related Disease, Life Science Institute of Jinzhou Medical University, Jinzhou 121001, Liaoning, China.
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Agarwal AK, Tunison K, Horton JD, Garg A. Regulated regeneration of adipose tissue in lipodystrophic Agpat2-null mice partially ameliorates hepatic steatosis. iScience 2024; 27:109517. [PMID: 38623324 PMCID: PMC11016861 DOI: 10.1016/j.isci.2024.109517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 01/22/2024] [Accepted: 03/14/2024] [Indexed: 04/17/2024] Open
Abstract
Both humans and mice with congenital generalized lipodystrophy due to AGPAT2 deficiency develop diabetes mellitus, insulin resistance, and hepatic steatosis, which have been attributed to the near total loss of adipose tissue (AT). Here, we show that regulated AT regeneration in doxycycline (dox)-fed Tg-AT-hAGPAT2;mAgpat2-/- mice partially ameliorates hepatic steatosis at 12 weeks of age and causes reduced expression of genes involved in hepatic de novo lipogenesis despite partial (∼30-50%) AT regeneration compared to that in wild-type mice. Compared to chow-fed Tg-AT-hAGPAT2;mAgpat2-/- mice, those fed dox diet had markedly reduced serum insulin levels, suggesting an improvement in insulin resistance. Interestingly, the fasting plasma glucose levels in dox-fed Tg-AT-hAGPAT2;mAgpat2-/- mice were no different than those in chow-fed wild-type mice. Indirect calorimetry revealed normalization in the energy balance of dox-fed Tg-AT-hAGPAT2;mAgpat2-/- mice compared to that in chow-fed mice. This study's findings suggest that partial AT regeneration in lipodystrophic mice can ameliorate metabolic derangements.
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Affiliation(s)
- Anil K. Agarwal
- Section of Nutrition and Metabolic Diseases, Division of Endocrinology, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX 75390, USA
- Center for Human Nutrition, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Katie Tunison
- Section of Nutrition and Metabolic Diseases, Division of Endocrinology, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX 75390, USA
- Center for Human Nutrition, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jay D. Horton
- Center for Human Nutrition, UT Southwestern Medical Center, Dallas, TX 75390, USA
- Department of Molecular Genetics, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Abhimanyu Garg
- Section of Nutrition and Metabolic Diseases, Division of Endocrinology, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX 75390, USA
- Center for Human Nutrition, UT Southwestern Medical Center, Dallas, TX 75390, USA
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Guo L, Lei J, Li P, Wang Y, Wang J, Song T, Zhu B, Jia J, Miao J, Cui H. Hedan tablet ameliorated non-alcoholic steatohepatitis by moderating NF-κB and lipid metabolism-related pathways via regulating hepatic metabolites. J Cell Mol Med 2024; 28:e18194. [PMID: 38506086 DOI: 10.1111/jcmm.18194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 12/20/2023] [Accepted: 01/09/2024] [Indexed: 03/21/2024] Open
Abstract
Non-alcoholic steatohepatitis (NASH) is a severe form of fatty liver disease. If not treated, it can lead to liver damage, cirrhosis and even liver cancer. However, advances in treatment have remained relatively slow, and there is thus an urgent need to develop appropriate treatments. Hedan tablet (HDP) is used to treat metabolic syndrome. However, scientific understanding of the therapeutic effect of HDP on NASH remains limited. We used HDP to treat a methionine/choline-deficient diet-induced model of NASH in rats to elucidate the therapeutic effects of HDP on liver injury. In addition, we used untargeted metabolomics to investigate the effects of HDP on metabolites in liver of NASH rats, and further validated its effects on inflammation and lipid metabolism following screening for potential target pathways. HDP had considerable therapeutic, anti-oxidant, and anti-inflammatory effects on NASH. HDP could also alter the hepatic metabolites changed by NASH. Moreover, HDP considerable moderated NF-κB and lipid metabolism-related pathways. The present study found that HDP had remarkable therapeutic effects in NASH rats. The therapeutic efficacy of HDP in NASH mainly associated with regulation of NF-κB and lipid metabolism-related pathways via arachidonic acid metabolism, glycine-serine-threonine metabolism, as well as steroid hormone biosynthesis.
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Affiliation(s)
- Liying Guo
- Department of Chinese Medicine, Tianjin Second People's Hospital, Tianjin, China
| | - Jinyan Lei
- Department of Chinese Medicine, Tianjin Second People's Hospital, Tianjin, China
| | - Peng Li
- Department of Chinese Medicine, Tianjin Second People's Hospital, Tianjin, China
| | - Yuming Wang
- Graduate School, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Jing Wang
- Department of Chinese Medicine, Tianjin Second People's Hospital, Tianjin, China
| | - Taotao Song
- Department of Chinese Medicine, Tianjin Second People's Hospital, Tianjin, China
| | - Bo Zhu
- Department of Chinese Medicine, Tianjin Second People's Hospital, Tianjin, China
| | - Jianwei Jia
- Department of Chinese Medicine, Tianjin Second People's Hospital, Tianjin, China
| | - Jing Miao
- Department of Chinese Medicine, Tianjin Second People's Hospital, Tianjin, China
| | - Huantian Cui
- First School of Clinical Medicine, Yunnan University of Chinese Medicine, Kunming, China
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Ma Z, Wang W, Zhang D, Zhang Y, Zhao Y, Li X, Zhao L, Cheng J, Xu D, Yang X, Liu J, He L, Chen Z, Gong P, Zhang X. Polymorphisms of PLIN1 and MOGAT1 genes and their association with feed efficiency in Hu sheep. Gene 2024; 897:148072. [PMID: 38081333 DOI: 10.1016/j.gene.2023.148072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 11/22/2023] [Accepted: 12/08/2023] [Indexed: 12/21/2023]
Abstract
Feed cost accounts for a high proportion of sheep production, and improving sheep's utilization of feed will reduce production costs and improve economic benefits. The purpose of this study was to investigate the expression characteristics of PLIN1 and MOGAT1 genes and the relationship between their polymorphisms and feed efficiency traits in Hu sheep, and to find molecular Genetic marker that can be used in breeding. The expression levels of PLIN1 and MOGAT1 genes in various tissues were determined using quantitative real-time PCR (qRT-PCR). The results showed that PLIN1 and MOGAT1 genes were widely expressed in heart, liver, spleen, lungs, kidneys, rumen, duodenum, muscle, lymph, and tail fat. The PLIN1 gene had the highest expression level in in the tail fat compared to the other nine tissues. The expression levels of MOGAT1 gene in liver, tail fat, lung and heart was significantly higher than in kidney, muscle and lymph. The expression level of MOGAT1 was lowest in muscle compared to the other tissues (heart, liver, spleen, lung, rumen and tail fat). We recorded the body weight (BW80 and BW180) and feed intake (FI) information of 985 male Hu sheep at 80 and 180 days of age, and calculated the daily average feed intake (ADFI), average daily gain (ADG), and feed conversion rate (FCR) from 80 to 180 days of age. Two intronic mutations, g.18517910 A > G and g.224856118 G > C, were identified in PLIN1 and MOGAT1 genes by PCR amplification and Sanger sequencing. MassARRAY ® SNP detection technology was used to genotype the DNA of 985 Hu sheep and analyze its association with feed efficiency traits. The results showed that the SNP g.18517910 A > G was significantly associated with BW80, BW180, FI, ADFI and FCR (P < 0.05), while SNP g.2248561118 G > C was significantly associated with FCR (P < 0.05). Meanwhile, significant differences were also observed in different combinations of genotypes (P < 0.05). Therefore, these two polymorphic loci can serve as candidate molecular markers for improving feed utilization efficiency in Hu sheep.
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Affiliation(s)
- Zongwu Ma
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, Gansu 730070, China
| | - Weimin Wang
- The State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou Gansu 730020, China
| | - Deyin Zhang
- The State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou Gansu 730020, China
| | - Yukun Zhang
- The State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou Gansu 730020, China
| | - Yuan Zhao
- The State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou Gansu 730020, China
| | - Xiaolong Li
- The State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou Gansu 730020, China
| | - Liming Zhao
- The State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou Gansu 730020, China
| | - Jiangbo Cheng
- The State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou Gansu 730020, China
| | - Dan Xu
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, Gansu 730070, China
| | - Xiaobin Yang
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, Gansu 730070, China
| | - Jia Liu
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, Gansu 730070, China
| | - Lijuan He
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, Gansu 730070, China
| | - Zhanyu Chen
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, Gansu 730070, China
| | - Ping Gong
- Institute of Animal Husbandry Quality Standards, Xinjiang Academy of Animal Science, Urumqi, 830057, China.
| | - Xiaoxue Zhang
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, Gansu 730070, China.
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Wei M, Yi P, Huang B, Naz S, Ge C, Shu-Chien AC, Wang Z, Wu X. Insights into sequence characteristics and evolutionary history of DGATs in arthropods. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART D, GENOMICS & PROTEOMICS 2024; 49:101195. [PMID: 38266530 DOI: 10.1016/j.cbd.2024.101195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 01/08/2024] [Accepted: 01/16/2024] [Indexed: 01/26/2024]
Abstract
Triacylglycerol (TAG) is crucial in animal energy storage and membrane biogenesis. The conversion of diacylglycerol (DAG) to triacylglycerol (TAG) is catalyzed by diacylglycerol acyltransferase enzymes (DGATs), which are encoded by genes belonging to two distinct gene families. Although arthropods are known to possess DGATs activities and utilize the glycerol-3-phosphate pathway and MAG pathway for TAG biosynthesis, the sequence characterization and evolutionary history of DGATs in arthropods remains unclear. This study aimed to comparatively evaluate genomic analyses of DGATs in 13 arthropod species and 14 outgroup species. We found that arthropods lack SOAT2 genes within the DGAT1 family, while DGAT2, MOGAT3, AWAT1, and AWAT2 were absent from in DGAT2 family. Gene structure and phylogenetic analyses revealed that DGAT1 and DGAT2 genes come from different gene families. The expression patterns of these genes were further analyzed in crustaceans, demonstrating the importance of DGAT1 in TAG biosynthesis. Additionally, we identified the DGAT1 gene in Swimming crab (P. trituberculatus) undergoes a mutually exclusive alternative splicing event in the molt stages. Our newly determined DGAT inventory data provide a more complete scenario and insights into the evolutionary dynamics and functional diversification of DGATs in arthropods.
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Affiliation(s)
- Maolei Wei
- Centre for Research on Fish Nutrition and Environmental Ecology of the Ministry of Agriculture, Shanghai Ocean University, Shanghai 201306, China; College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo 315100, China
| | - Peng Yi
- Centre for Research on Fish Nutrition and Environmental Ecology of the Ministry of Agriculture, Shanghai Ocean University, Shanghai 201306, China
| | - Baoyou Huang
- Institute of Animal Sex and Development, Zhejiang Wanli University, Ningbo 315100, China; College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo 315100, China
| | - Saira Naz
- Centre for Research on Fish Nutrition and Environmental Ecology of the Ministry of Agriculture, Shanghai Ocean University, Shanghai 201306, China
| | - Chutian Ge
- Institute of Animal Sex and Development, Zhejiang Wanli University, Ningbo 315100, China; College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo 315100, China
| | - Alexander Chong Shu-Chien
- School of Biological Sciences, University Sains Malaysia, Minden, 11800 Penang, Malaysia; Center for Chemical Biology, University Sains Malaysia, 11900 Bayan Lepas, Penang, Malaysia
| | - Zongji Wang
- Institute of Animal Sex and Development, Zhejiang Wanli University, Ningbo 315100, China; College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo 315100, China.
| | - Xugan Wu
- Centre for Research on Fish Nutrition and Environmental Ecology of the Ministry of Agriculture, Shanghai Ocean University, Shanghai 201306, China; National Demonstration Centre for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, China.
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Öling S, Struck E, Noreen-Thorsen M, Zwahlen M, von Feilitzen K, Odeberg J, Pontén F, Lindskog C, Uhlén M, Dusart P, Butler LM. A human stomach cell type transcriptome atlas. BMC Biol 2024; 22:36. [PMID: 38355543 PMCID: PMC10865703 DOI: 10.1186/s12915-024-01812-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 01/02/2024] [Indexed: 02/16/2024] Open
Abstract
BACKGROUND The identification of cell type-specific genes and their modification under different conditions is central to our understanding of human health and disease. The stomach, a hollow organ in the upper gastrointestinal tract, provides an acidic environment that contributes to microbial defence and facilitates the activity of secreted digestive enzymes to process food and nutrients into chyme. In contrast to other sections of the gastrointestinal tract, detailed descriptions of cell type gene enrichment profiles in the stomach are absent from the major single-cell sequencing-based atlases. RESULTS Here, we use an integrative correlation analysis method to predict human stomach cell type transcriptome signatures using unfractionated stomach RNAseq data from 359 individuals. We profile parietal, chief, gastric mucous, gastric enteroendocrine, mitotic, endothelial, fibroblast, macrophage, neutrophil, T-cell, and plasma cells, identifying over 1600 cell type-enriched genes. CONCLUSIONS We uncover the cell type expression profile of several non-coding genes strongly associated with the progression of gastric cancer and, using a sex-based subset analysis, uncover a panel of male-only chief cell-enriched genes. This study provides a roadmap to further understand human stomach biology.
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Affiliation(s)
- S Öling
- Department of Clinical Medicine, Translational Vascular Research, The Arctic University of Norway, 9019, Tromsø, Norway
| | - E Struck
- Department of Clinical Medicine, Translational Vascular Research, The Arctic University of Norway, 9019, Tromsø, Norway
| | - M Noreen-Thorsen
- Department of Clinical Medicine, Translational Vascular Research, The Arctic University of Norway, 9019, Tromsø, Norway
| | - M Zwahlen
- Science for Life Laboratory, Department of Protein Science, Royal Institute of Technology (KTH), 171 21, Stockholm, Sweden
| | - K von Feilitzen
- Science for Life Laboratory, Department of Protein Science, Royal Institute of Technology (KTH), 171 21, Stockholm, Sweden
| | - J Odeberg
- Department of Clinical Medicine, Translational Vascular Research, The Arctic University of Norway, 9019, Tromsø, Norway
- Science for Life Laboratory, Department of Protein Science, Royal Institute of Technology (KTH), 171 21, Stockholm, Sweden
- The University Hospital of North Norway (UNN), 9019, Tromsø, Norway
- Department of Haematology, Coagulation Unit, Karolinska University Hospital, 171 76, Stockholm, Sweden
| | - F Pontén
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, 752 37, Uppsala, Sweden
| | - C Lindskog
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, 752 37, Uppsala, Sweden
| | - M Uhlén
- Science for Life Laboratory, Department of Protein Science, Royal Institute of Technology (KTH), 171 21, Stockholm, Sweden
| | - P Dusart
- Science for Life Laboratory, Department of Protein Science, Royal Institute of Technology (KTH), 171 21, Stockholm, Sweden
- Clinical Chemistry and Blood Coagulation Research, Department of Molecular Medicine and Surgery, Karolinska Institute, 171 76, Stockholm, Sweden
- Clinical Chemistry, Karolinska University Laboratory, Karolinska University Hospital, 171 76, Stockholm, Sweden
| | - L M Butler
- Department of Clinical Medicine, Translational Vascular Research, The Arctic University of Norway, 9019, Tromsø, Norway.
- Science for Life Laboratory, Department of Protein Science, Royal Institute of Technology (KTH), 171 21, Stockholm, Sweden.
- Clinical Chemistry and Blood Coagulation Research, Department of Molecular Medicine and Surgery, Karolinska Institute, 171 76, Stockholm, Sweden.
- Clinical Chemistry, Karolinska University Laboratory, Karolinska University Hospital, 171 76, Stockholm, Sweden.
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Meng W, Brigance R, Mignone J, Negash L, Zhao G, Ahmad S, Wang W, Moore F, Ye XY, Sun JH, Mathur A, Li YX, Azzara A, Ma Z, Chu CH, Cullen MJ, Rooney S, Harvey S, Kopcho L, Abell L, O'Malley K, Keim W, Dierks EA, Chang S, Foster KA, Harden D, Dabros M, Goti V, De Oliveira C, Krishna G, Pelleymounter MA, Whaley J, Robl JA, Cheng D, Devasthale P. Discovery of 12 (BMS-986172) as a Highly Potent MGAT2 Inhibitor that Achieved Targeted Efficacious Exposures at a Low Human Dose for the Treatment of Metabolic Disorders. J Med Chem 2023; 66:13135-13147. [PMID: 37724542 DOI: 10.1021/acs.jmedchem.3c01147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/21/2023]
Abstract
A series of dihydropyridinone (DHP) compounds was prepared and evaluated for MGAT2 activity. The efforts led to the identification of novel tetrazolones with potent MGAT2 inhibitory activity and favorable in vitro profiles. Further tests of select analogues in mouse models revealed significant reduction in food intake and body weight. Subsequent studies in MGAT2 knockout mice with the lead candidate 12 (BMS-986172) showed on-target- and mechanism-based pharmacology. Moreover, its favorable pharmacokinetic (PK) profile and the lack of species variability in the glucuronidation potential resulted in a greater confidence level in the projection of a low dose for achieving targeted efficacious exposures in humans. Consistent with these projections, PK data from a phase 1 trial confirmed that targeted efficacious exposures could be achieved at a low dose in humans, which supported compound 12 as our second and potentially superior development candidate for the treatment of various metabolic disorders.
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Kimura T, Kimura AK, Epand RM. Systematic crosstalk in plasmalogen and diacyl lipid biosynthesis for their differential yet concerted molecular functions in the cell. Prog Lipid Res 2023; 91:101234. [PMID: 37169310 DOI: 10.1016/j.plipres.2023.101234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 04/29/2023] [Accepted: 05/05/2023] [Indexed: 05/13/2023]
Abstract
Plasmalogen is a major phospholipid of mammalian cell membranes. Recently it is becoming evident that the sn-1 vinyl-ether linkage in plasmalogen, contrasting to the ester linkage in the counterpart diacyl glycerophospholipid, yields differential molecular characteristics for these lipids especially related to hydrocarbon-chain order, so as to concertedly regulate biological membrane processes. A role played by NMR in gaining information in this respect, ranging from molecular to tissue levels, draws particular attention. We note here that a broad range of enzymes in de novo synthesis pathway of plasmalogen commonly constitute that of diacyl glycerophospholipid. This fact forms the basis for systematic crosstalk that not only controls a quantitative balance between these lipids, but also senses a defect causing loss of lipid in either pathway for compensation by increase of the counterpart lipid. However, this inherent counterbalancing mechanism paradoxically amplifies imbalance in differential effects of these lipids in a diseased state on membrane processes. While sharing of enzymes has been recognized, it is now possible to overview the crosstalk with growing information for specific enzymes involved. The overview provides a fundamental clue to consider cell and tissue type-dependent schemes in regulating membrane processes by plasmalogen and diacyl glycerophospholipid in health and disease.
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Affiliation(s)
- Tomohiro Kimura
- Department of Chemistry & Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, USA.
| | - Atsuko K Kimura
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - Richard M Epand
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
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9
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Chalhoub G, Jamnik A, Pajed L, Kolleritsch S, Hois V, Bagaric A, Prem D, Tilp A, Kolb D, Wolinski H, Taschler U, Züllig T, Rechberger GN, Fuchs C, Trauner M, Schoiswohl G, Haemmerle G. Carboxylesterase 2a deletion provokes hepatic steatosis and insulin resistance in mice involving impaired diacylglycerol and lysophosphatidylcholine catabolism. Mol Metab 2023; 72:101725. [PMID: 37059417 PMCID: PMC10148186 DOI: 10.1016/j.molmet.2023.101725] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 04/04/2023] [Accepted: 04/08/2023] [Indexed: 04/16/2023] Open
Abstract
OBJECTIVE Hepatic triacylglycerol accumulation and insulin resistance are key features of NAFLD. However, NAFLD development and progression are rather triggered by the aberrant generation of lipid metabolites and signaling molecules including diacylglycerol (DAG) and lysophosphatidylcholine (lysoPC). Recent studies showed decreased expression of carboxylesterase 2 (CES2) in the liver of NASH patients and hepatic DAG accumulation was linked to low CES2 activity in obese individuals. The mouse genome encodes several Ces2 genes with Ces2a showing highest expression in the liver. Herein we investigated the role of mouse Ces2a and human CES2 in lipid metabolism in vivo and in vitro. METHODS Lipid metabolism and insulin signaling were investigated in mice lacking Ces2a and in a human liver cell line upon pharmacological CES2 inhibition. Lipid hydrolytic activities were determined in vivo and from recombinant proteins. RESULTS Ces2a deficient mice (Ces2a-ko) are obese and feeding a high-fat diet (HFD) provokes severe hepatic steatosis and insulin resistance together with elevated inflammatory and fibrotic gene expression. Lipidomic analysis revealed a marked rise in DAG and lysoPC levels in the liver of Ces2a-ko mice fed HFD. Hepatic lipid accumulation in Ces2a deficiency is linked to lower DAG and lysoPC hydrolytic activities in liver microsomal preparations. Moreover, Ces2a deficiency significantly increases hepatic expression and activity of MGAT1, a PPAR gamma target gene, suggesting aberrant lipid signaling upon Ces2a deficiency. Mechanistically, we found that recombinant Ces2a and CES2 show significant hydrolytic activity towards lysoPC (and DAG) and pharmacological inhibition of CES2 in human HepG2 cells largely phenocopies the lipid metabolic changes present in Ces2a-ko mice including reduced lysoPC and DAG hydrolysis, DAG accumulation and impaired insulin signaling. CONCLUSIONS Ces2a and CES2 are critical players in hepatic lipid signaling likely via the hydrolysis of DAG and lysoPC at the ER.
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Affiliation(s)
- Gabriel Chalhoub
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Alina Jamnik
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Laura Pajed
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | | | - Victoria Hois
- Division of Endocrinology and Diabetology, Medical University of Graz, Austria
| | - Antonia Bagaric
- Department of Pharmacology and Toxicology, University of Graz, Graz, Austria
| | - Dominik Prem
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Anna Tilp
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Dagmar Kolb
- Core Facility Ultrastructure Analysis, Medical University of Graz, Graz, Austria
| | - Heimo Wolinski
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Ulrike Taschler
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Thomas Züllig
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | | | - Claudia Fuchs
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Michael Trauner
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Gabriele Schoiswohl
- Department of Pharmacology and Toxicology, University of Graz, Graz, Austria.
| | - Guenter Haemmerle
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.
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10
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Korbecki J, Bosiacki M, Gutowska I, Chlubek D, Baranowska-Bosiacka I. Biosynthesis and Significance of Fatty Acids, Glycerophospholipids, and Triacylglycerol in the Processes of Glioblastoma Tumorigenesis. Cancers (Basel) 2023; 15:cancers15072183. [PMID: 37046844 PMCID: PMC10093493 DOI: 10.3390/cancers15072183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 04/01/2023] [Accepted: 04/03/2023] [Indexed: 04/08/2023] Open
Abstract
One area of glioblastoma research is the metabolism of tumor cells and detecting differences between tumor and healthy brain tissue metabolism. Here, we review differences in fatty acid metabolism, with a particular focus on the biosynthesis of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA) by fatty acid synthase (FASN), elongases, and desaturases. We also describe the significance of individual fatty acids in glioblastoma tumorigenesis, as well as the importance of glycerophospholipid and triacylglycerol synthesis in this process. Specifically, we show the significance and function of various isoforms of glycerol-3-phosphate acyltransferases (GPAT), 1-acylglycerol-3-phosphate O-acyltransferases (AGPAT), lipins, as well as enzymes involved in the synthesis of phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylinositol (PI), and cardiolipin (CL). This review also highlights the involvement of diacylglycerol O-acyltransferase (DGAT) in triacylglycerol biosynthesis. Due to significant gaps in knowledge, the GEPIA database was utilized to demonstrate the significance of individual enzymes in glioblastoma tumorigenesis. Finally, we also describe the significance of lipid droplets in glioblastoma and the impact of fatty acid synthesis, particularly docosahexaenoic acid (DHA), on cell membrane fluidity and signal transduction from the epidermal growth factor receptor (EGFR).
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Affiliation(s)
- Jan Korbecki
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, Powstańców Wlkp. 72, 70-111 Szczecin, Poland
- Department of Anatomy and Histology, Collegium Medicum, University of Zielona Góra, Zyty 28 Str., 65-046 Zielona Góra, Poland
| | - Mateusz Bosiacki
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, Powstańców Wlkp. 72, 70-111 Szczecin, Poland
- Department of Functional Diagnostics and Physical Medicine, Faculty of Health Sciences, Pomeranian Medical University in Szczecin, Żołnierska 54 Str., 71-210 Szczecin, Poland
| | - Izabela Gutowska
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, Powstańców Wlkp. 72, 70-111 Szczecin, Poland
| | - Dariusz Chlubek
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, Powstańców Wlkp. 72, 70-111 Szczecin, Poland
| | - Irena Baranowska-Bosiacka
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, Powstańców Wlkp. 72, 70-111 Szczecin, Poland
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11
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Yang J, Guo F, Chin HS, Chen GB, Ang CH, Lin Q, Hong W, Fu NY. Sequential genome-wide CRISPR-Cas9 screens identify genes regulating cell-surface expression of tetraspanins. Cell Rep 2023; 42:112065. [PMID: 36724073 DOI: 10.1016/j.celrep.2023.112065] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 11/16/2022] [Accepted: 01/18/2023] [Indexed: 02/02/2023] Open
Abstract
Tetraspanins, a superfamily of membrane proteins, mediate diverse biological processes through tetraspanin-enriched microdomains in the plasma membrane. However, how their cell-surface presentation is controlled remains unclear. To identify the regulators of tetraspanin trafficking, we conduct sequential genome-wide loss-of-function CRISPR-Cas9 screens based on cell-surface expression of a tetraspanin member, TSPAN8. Several genes potentially involved in endoplasmic reticulum (ER) targeting, different biological processes in the Golgi apparatus, and protein trafficking are identified and functionally validated. Importantly, we find that biantennary N-glycans generated by MGAT1/2, but not more complex glycan structures, are important for cell-surface tetraspanin expression. Moreover, we unravel that SPPL3, a Golgi intramembrane-cleaving protease reported previously to act as a sheddase of multiple glycan-modifying enzymes, controls cell-surface tetraspanin expression through a mechanism associated with lacto-series glycolipid biosynthesis. Our study provides critical insights into the molecular regulation of cell-surface presentation of tetraspanins with implications for strategies to manipulate their functions, including cancer cell invasion.
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Affiliation(s)
- Jicheng Yang
- Cancer and Stem Cell Biology Program, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Fusheng Guo
- Cancer and Stem Cell Biology Program, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Hui San Chin
- Cancer and Stem Cell Biology Program, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Gao Bin Chen
- Cancer and Stem Cell Biology Program, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Chow Hiang Ang
- Cancer and Stem Cell Biology Program, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Qingsong Lin
- Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Wanjin Hong
- Institute of Molecular and Cell Biology, Agency for Science, Technology, and Research (A(∗)STAR), Singapore 138673, Singapore
| | - Nai Yang Fu
- Cancer and Stem Cell Biology Program, Duke-NUS Medical School, Singapore 169857, Singapore; Department of Physiology, National University of Singapore, Singapore 117593, Singapore; Stem Cells and Cancer Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; Department of Medicine, University of Melbourne, Parkville, VIC 3010, Australia.
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12
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Active Glycogen Synthase in the Liver Prevents High-Fat Diet-Induced Glucose Intolerance, Decreases Food Intake, and Lowers Body Weight. Int J Mol Sci 2023; 24:ijms24032574. [PMID: 36768897 PMCID: PMC9917303 DOI: 10.3390/ijms24032574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/19/2023] [Accepted: 01/23/2023] [Indexed: 01/31/2023] Open
Abstract
Many lines of evidence demonstrate a correlation between liver glycogen content and food intake. We previously demonstrated that mice overexpressing protein targeting to glycogen (PTG) specifically in the liver-which have increased glycogen content in this organ-are protected from high-fat diet (HFD)-induced obesity by reduced food intake. However, the use of PTG to increase liver glycogen implies certain limitations. PTG stimulates glycogen synthesis but also inhibits the enzyme responsible for glycogen degradation. Furthermore, as PTG is a regulatory subunit of protein phosphatase 1 (PP1), which regulates many cellular functions, its overexpression could have side effects beyond the regulation of glycogen metabolism. Therefore, it is necessary to determine whether the direct activation of glycogen synthesis, without affecting its degradation or other cellular functions, has the same effects. To this end, we generated mice overexpressing a non-inactivatable form of glycogen synthase (GS) specifically in the liver (9A-MGSAlb mice). Control and 9a-MGSAlb mice were fed a standard diet (SD) or HFD for 16 weeks. Glucose tolerance and feeding behavior were analyzed. 9A-MGSAlb mice showed an increase in hepatic glycogen in fed and fasting conditions. When fed an HFD, these animals preserved their hepatic energy state, had a reduced food intake, and presented a lower body weight and fat mass than control animals, without changes in energy expenditure. Furthermore, 9A-MGSAlb animals showed improved glucose tolerance when fed an SD or HFD. Moreover, liver triacylglycerol levels that were increased after HFD feeding were lower in these mice. These results confirm that increased liver glycogen stores contribute to decreased appetite and improve glucose tolerance in mice fed an HFD. On the basis of our findings, strategies to preserve hepatic glycogen stores emerge as potential treatments for obesity and hyperglycemia.
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13
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Wang Y, Zeng F, Zhao Z, He L, He X, Pang H, Huang F, Chang P. Transmembrane Protein 68 Functions as an MGAT and DGAT Enzyme for Triacylglycerol Biosynthesis. Int J Mol Sci 2023; 24:ijms24032012. [PMID: 36768334 PMCID: PMC9916437 DOI: 10.3390/ijms24032012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Revised: 01/15/2023] [Accepted: 01/17/2023] [Indexed: 01/20/2023] Open
Abstract
Triacylglycerol (TG) biosynthesis is an important metabolic process for intracellular storage of surplus energy, intestinal dietary fat absorption, attenuation of lipotoxicity, lipid transportation, lactation and signal transduction in mammals. Transmembrane protein 68 (TMEM68) is an endoplasmic reticulum (ER)-anchored acyltransferase family member of unknown function. In the current study we show that overexpression of TMEM68 promotes TG accumulation and lipid droplet (LD) formation in a conserved active sites-dependent manner. Quantitative targeted lipidomic analysis showed that diacylglycerol (DG), free fatty acid (FFA) and TG levels were increased by TMEM68 expression. In addition, TMEM68 overexpression affected the levels of several glycerophospholipids, such as phosphatidylcholine, phosphatidylethanolamine and phosphatidylinositol, as well as sterol ester contents. TMEM68 exhibited monoacylglycerol acyltransferase (MGAT) and diacylglycerol acyltransferase (DGAT) activities dependent on the conserved active sites in an in vitro assay. The expression of lipogenesis genes, including DGATs, fatty acid synthesis-related genes and peroxisome proliferator-activated receptor γ was upregulated in TMEM68-overexpressing cells. These results together demonstrate for the first time that TMEM68 functions as an acyltransferase and affects lipogenic gene expression, glycerolipid metabolism and TG storage in mammalian cells.
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14
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Singer JM, Shew TM, Ferguson D, Renkemeyer MK, Pietka TA, Hall AM, Finck BN, Lutkewitte AJ. Monoacylglycerol O-acyltransferase 1 lowers adipocyte differentiation capacity in vitro but does not affect adiposity in mice. Obesity (Silver Spring) 2022; 30:2122-2133. [PMID: 36321276 PMCID: PMC9634674 DOI: 10.1002/oby.23538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 06/20/2022] [Accepted: 06/23/2022] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Monoacylglycerol O-acyltransferase 1 (Mogat1), a lipogenic enzyme that converts monoacylglycerol to diacylglycerol, is highly expressed in adipocytes and may regulate lipolysis by re-esterifying fatty acids released during times when lipolytic rates are low. However, the role of Mogat1 in regulating adipocyte fat storage during differentiation and diet-induced obesity is relatively understudied. METHODS Here, adipocyte-specific Mogat1 knockout mice were generated and subjected to a high-fat diet to determine the effects of Mogat1 deficiency on diet-induced obesity. Mogat1 floxed mice were also used to develop preadipocyte cell lines wherein Mogat1 could be conditionally knocked out to study adipocyte differentiation in vitro. RESULTS In preadipocytes, it was found that Mogat1 knockout at the onset of preadipocyte differentiation prevented the accumulation of glycerolipids and reduced the differentiation capacity of preadipocytes. However, the loss of adipocyte Mogat1 did not affect weight gain or fat mass induced by a high-fat diet in mice. Furthermore, loss of Mogat1 in adipocytes did not affect plasma lipid or glucose concentrations or insulin tolerance. CONCLUSIONS These data suggest Mogat1 may play a role in adipocyte differentiation in vitro but not adipose tissue expansion in response to nutrient overload in mice.
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Affiliation(s)
- Jason M. Singer
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO
| | - Trevor M. Shew
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO
| | - Daniel Ferguson
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO
| | - M. Katie Renkemeyer
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO
| | - Terri A. Pietka
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO
| | - Angela M. Hall
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO
| | - Brian N. Finck
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO
| | - Andrew J. Lutkewitte
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO
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15
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Gökçe G, Bayraktar M. Assessment of the association of the MOGAT1 and MOGAT3 gene with growth traits in different growth stages in Holstein calves. Arch Anim Breed 2022; 65:301-308. [PMID: 36035878 PMCID: PMC9400126 DOI: 10.5194/aab-65-301-2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 07/22/2022] [Indexed: 11/11/2022] Open
Abstract
The members of the monoacylglycerol acyltransferase (MOGAT) family are essential candidate genes that influence economic traits associated with triglyceride synthesis, dietary fat absorption, and storage in livestock. In addition, the MOGAT gene family may also play an essential function in human polygenic diseases, like type 2 diabetes and obesity. The present study was conducted on Holstein calves to find the association between MOGAT1, MOGAT3/g.A229G, and MOGAT3/g.G1627A and growth traits. The polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) method was performed for genotyping the MOGAT1, MOGAT3/g.A229G, and MOGAT3/g.G1627A genes' locus using the TaqI, MspI, and BsuRI restriction enzyme. The allele frequency of A and G of the MOGAT1 locus was 0.79 and 0.21, respectively, while the genotype frequency was 0.65, 0.28, and 0.07 for AA, AG, and GG, respectively. While the allele and genotype frequencies of the MOGAT3/g.A229G locus were 00.57(A1), 0.43(G1), 0.35(A1A1), 0.45(A1G1), and 0.20(G1G1), the allele and genotype frequencies of the MOGAT3/g.G1627A locus were 0.49(A2), 0.51(G2), 0.25(A2A2), 0.49(A2G2), and 0.26(G2G2). Chi-square analysis showed that MOGAT3/g.G1627A distribution was at the Hardy–Weinberg disequilibrium (p < 0.05), and MOGAT1 and MOGAT3/g.A229G distribution was at the Hardy–Weinberg equilibrium (p > 0.05). In total, two statistical methods (general linear model (GLM) and PROC MIXED) were used to identify an association between gene locus and growth traits. An association analysis showed a statistically significant difference between the MOGAT1 and body weight, body length, and chest circumference, MOGAT3/g.A229G with average daily gain (ADG) and withers height, and MOGAT3/g.G1627A with body weight and body length (p < 0.05). The results confirmed that the MOGAT1, MOGAT3/g.A229G, and MOGAT3/g.G1627A locus are strong candidate genes that could be considered molecular markers for growth traits in cattle breeding.
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16
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Chen G, Harwood JL, Lemieux MJ, Stone SJ, Weselake RJ. Acyl-CoA:diacylglycerol acyltransferase: Properties, physiological roles, metabolic engineering and intentional control. Prog Lipid Res 2022; 88:101181. [PMID: 35820474 DOI: 10.1016/j.plipres.2022.101181] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 05/31/2022] [Accepted: 07/04/2022] [Indexed: 12/15/2022]
Abstract
Acyl-CoA:diacylglycerol acyltransferase (DGAT, EC 2.3.1.20) catalyzes the last reaction in the acyl-CoA-dependent biosynthesis of triacylglycerol (TAG). DGAT activity resides mainly in membrane-bound DGAT1 and DGAT2 in eukaryotes and bifunctional wax ester synthase-diacylglycerol acyltransferase (WSD) in bacteria, which are all membrane-bound proteins but exhibit no sequence homology to each other. Recent studies also identified other DGAT enzymes such as the soluble DGAT3 and diacylglycerol acetyltransferase (EaDAcT), as well as enzymes with DGAT activities including defective in cuticular ridges (DCR) and steryl and phytyl ester synthases (PESs). This review comprehensively discusses research advances on DGATs in prokaryotes and eukaryotes with a focus on their biochemical properties, physiological roles, and biotechnological and therapeutic applications. The review begins with a discussion of DGAT assay methods, followed by a systematic discussion of TAG biosynthesis and the properties and physiological role of DGATs. Thereafter, the review discusses the three-dimensional structure and insights into mechanism of action of human DGAT1, and the modeled DGAT1 from Brassica napus. The review then examines metabolic engineering strategies involving manipulation of DGAT, followed by a discussion of its therapeutic applications. DGAT in relation to improvement of livestock traits is also discussed along with DGATs in various other eukaryotic organisms.
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Affiliation(s)
- Guanqun Chen
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6H 2P5, Canada.
| | - John L Harwood
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
| | - M Joanne Lemieux
- Department of Biochemistry, University of Alberta, Membrane Protein Disease Research Group, Edmonton T6G 2H7, Canada
| | - Scot J Stone
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada.
| | - Randall J Weselake
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6H 2P5, Canada
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17
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The monoacylglycerol acyltransferase pathway contributes to triacylglycerol synthesis in HepG2 cells. Sci Rep 2022; 12:4943. [PMID: 35322811 PMCID: PMC8943211 DOI: 10.1038/s41598-022-08946-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 03/14/2022] [Indexed: 12/19/2022] Open
Abstract
The monoacylglycerol acyltransferase (MGAT) pathway has a well-established role in the small intestine where it facilitates the absorption of dietary fat. In enterocytes, MGAT participates in the resynthesis of triacylglycerol using substrates (monoacylglycerol and fatty acids) generated in the gut lumen from the breakdown of triacylglycerol consumed in the diet. MGAT activity is also present in the liver, but its role in triacylglycerol metabolism in this tissue remains unclear. The predominant MGAT isoforms present in human liver appear to be MGAT2 and MGAT3. The objective of this study was to use selective small molecule inhibitors of MGAT2 and MGAT3 to determine the contributions of these enzymes to triacylglycerol production in liver cells. We found that pharmacological inhibition of either enzyme had no effect on TG mass in HepG2 cells but did alter lipid droplet size and number. Inhibition of MGAT2 did result in decreased DG and TG synthesis and TG secretion. Interestingly, MGAT2 preferentially utilized 2-monoacylglycerol derived from free glycerol and not from exogenously added 2-monoacylglycerol. In contrast, inhibition of MGAT3 had very little effect on TG metabolism in HepG2 cells. Additionally, we demonstrated that the MGAT activity of DGAT1 only makes a minor contribution to TG synthesis in intact HepG2 cells. Our data demonstrated that the MGAT pathway has a role in hepatic lipid metabolism with MGAT2, more so than MGAT3, contributing to TG synthesis and secretion.
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18
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Stone SJ. Mechanisms of intestinal triacylglycerol synthesis. Biochim Biophys Acta Mol Cell Biol Lipids 2022; 1867:159151. [PMID: 35296424 DOI: 10.1016/j.bbalip.2022.159151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 01/13/2022] [Accepted: 02/16/2022] [Indexed: 02/07/2023]
Abstract
Triacylglycerols are a major source of stored energy that are obtained either from the diet or can be synthesized to some extent by most tissues. Alterations in pathways of triacylglycerol metabolism can result in their excessive accumulation leading to obesity, insulin resistance, cardiovascular disease and nonalcoholic fatty liver disease. Most tissues in mammals synthesize triacylglycerols via the glycerol 3-phosphate pathway. However, in the small intestine the monoacylglycerol acyltransferase pathway is the predominant pathway for triacylglycerol biosynthesis where it participates in the absorption of dietary triacylglycerol. In this review, the enzymes that are part of both the glycerol 3-phosphate and monoacylglycerol acyltransferase pathways and their contributions to intestinal triacylglycerol metabolism are reviewed. The potential of some of the enzymes involved in triacylglycerol synthesis in the small intestine as possible therapeutic targets for treating metabolic disorders associated with elevated triacylglycerol is briefly discussed.
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Affiliation(s)
- Scot J Stone
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada.
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19
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Walsh SC, Miles JR, Keel BN, Rempel LA, Wright-Johnson EC, Lindholm-Perry AK, Oliver WT, Pannier AK. Global analysis of differential gene expression within the porcine conceptus transcriptome as it transitions through spherical, ovoid, and tubular morphologies during the initiation of elongation. Mol Reprod Dev 2022; 89:175-201. [PMID: 35023252 PMCID: PMC9305853 DOI: 10.1002/mrd.23553] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 12/04/2021] [Accepted: 12/08/2021] [Indexed: 12/21/2022]
Abstract
This study aimed to identify transcriptome differences between distinct or transitional stage spherical, ovoid, and tubular porcine blastocysts throughout the initiation of elongation. We performed a global transcriptome analysis of differential gene expression using RNA‐Seq with high temporal resolution between spherical, ovoid, and tubular stage blastocysts at specific sequential stages of development from litters containing conceptus populations of distinct or transitional blastocysts. After RNA‐Seq analysis, significant differentially expressed genes (DEGs) and pathways were identified between distinct morphologies or sequential development stages. Overall, 1898 significant DEGs were identified between distinct spherical and ovoid morphologies, with 311 total DEGs between developmental stages throughout this first morphological transition, while 15 were identified between distinct ovoid and tubular, with eight total throughout these second morphological transition developmental stages. The high quantity of DEGs and pathways between conceptus stages throughout the spherical to ovoid transition suggests the importance of gene regulation during this first morphological transition for initiating elongation. Further, extensive DEG coverage of known elongation signaling pathways was illustrated from spherical to ovoid, and regulation of lipid signaling and membrane/ECM remodeling across these early conceptus stages were implicated as essential to this process, providing novel insights into potential mechanisms governing this rapid morphological change.
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Affiliation(s)
- Sophie C Walsh
- Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Jeremy R Miles
- U.S. Meat Animal Research Center, Clay Center, Nebraska, USA
| | - Brittney N Keel
- U.S. Meat Animal Research Center, Clay Center, Nebraska, USA
| | - Lea A Rempel
- U.S. Meat Animal Research Center, Clay Center, Nebraska, USA
| | | | | | | | - Angela K Pannier
- Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
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20
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Peng Y, Li H, Liu Z, Zhang C, Li K, Gong Y, Geng L, Su J, Guan X, Liu L, Zhou R, Zhao Z, Guo J, Liang Q, Li X. Chromosome-level genome assembly of the Arctic fox (Vulpes lagopus) using PacBio sequencing and Hi-C technology. Mol Ecol Resour 2021; 21:2093-2108. [PMID: 33829635 DOI: 10.1111/1755-0998.13397] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 03/28/2021] [Accepted: 03/30/2021] [Indexed: 10/21/2022]
Abstract
The Arctic fox (Vulpes lagopus) is the only fox species occurring in the Arctic and has adapted to its extreme climatic conditions. Currently, the molecular basis of its adaptation to the extreme climate has not been characterized. Here, we applied PacBio sequencing and chromosome structure capture technique to assemble the first V. lagopus genome assembly, which is assembled into chromosome fragments. The genome assembly has a total length of 2.345 Gb with a contig N50 of 31.848 Mb and a scaffold N50 of 131.537 Mb, consisting of 25 pseudochromosomal scaffolds. The V. lagopus genome had approximately 32.33% repeat sequences. In total, 21,278 protein-coding genes were predicted, of which 99.14% were functionally annotated. Compared with 12 other mammals, V. lagopus was most closely related to V. Vulpes with an estimated divergence time of ~7.1 Ma. The expanded gene families and positively selected genes potentially play roles in the adaptation of V. lagopus to Arctic extreme environment. This high-quality assembled genome will not only promote future studies of genetic diversity and evolution in foxes and other canids but also provide important resources for conservation of Arctic species.
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Affiliation(s)
- Yongdong Peng
- Hebei Key Laboratory of Specialty Animal Germplasm Resources Exploration and Innovation (Under Planning), College of Animal Science and Technology, Hebei Normal University of Science and Technology, Qinhuangdao, China
| | - Hong Li
- Novogene Bioinformatics Institute, Beijing, China
| | - Zhengzhu Liu
- Hebei Key Laboratory of Specialty Animal Germplasm Resources Exploration and Innovation (Under Planning), College of Animal Science and Technology, Hebei Normal University of Science and Technology, Qinhuangdao, China
| | - Chuansheng Zhang
- Hebei Key Laboratory of Specialty Animal Germplasm Resources Exploration and Innovation (Under Planning), College of Animal Science and Technology, Hebei Normal University of Science and Technology, Qinhuangdao, China
| | - Keqiang Li
- Hebei Key Laboratory of Specialty Animal Germplasm Resources Exploration and Innovation (Under Planning), College of Mathematics and Information Science, Hebei Normal University of Science and Technology, Qinhuangdao, China
| | - Yuanfang Gong
- Hebei Key Laboratory of Specialty Animal Germplasm Resources Exploration and Innovation (Under Planning), College of Animal Science and Technology, Hebei Normal University of Science and Technology, Qinhuangdao, China
| | - Liying Geng
- Hebei Key Laboratory of Specialty Animal Germplasm Resources Exploration and Innovation (Under Planning), College of Agronomy and Biotechnology, Hebei Normal University of Science and Technology, Qinhuangdao, China
| | - Jingjing Su
- Hebei Key Laboratory of Applied Chemistry, School of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao, China
| | - Xuemin Guan
- Hebei Key Laboratory of Specialty Animal Germplasm Resources Exploration and Innovation (Under Planning), College of Agronomy and Biotechnology, Hebei Normal University of Science and Technology, Qinhuangdao, China
| | - Lei Liu
- College of Animal Science and Technology, Shandong Agricultural University, Tai-an, China
| | - Ruihong Zhou
- Hebei Key Laboratory of Specialty Animal Germplasm Resources Exploration and Innovation (Under Planning), College of Animal Science and Technology, Hebei Normal University of Science and Technology, Qinhuangdao, China
| | - Ziya Zhao
- Hebei Key Laboratory of Specialty Animal Germplasm Resources Exploration and Innovation (Under Planning), College of Animal Science and Technology, Hebei Normal University of Science and Technology, Qinhuangdao, China
| | - Jianxu Guo
- Hebei Key Laboratory of Specialty Animal Germplasm Resources Exploration and Innovation (Under Planning), College of Animal Science and Technology, Hebei Normal University of Science and Technology, Qinhuangdao, China
| | - Qiqi Liang
- Novogene Bioinformatics Institute, Beijing, China
| | - Xianglong Li
- Hebei Key Laboratory of Specialty Animal Germplasm Resources Exploration and Innovation (Under Planning), College of Animal Science and Technology, Hebei Normal University of Science and Technology, Qinhuangdao, China
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21
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Sesorova IS, Dimov ID, Kashin AD, Sesorov VV, Karelina NR, Zdorikova MA, Beznoussenko GV, Mirоnоv AA. Cellular and sub-cellular mechanisms of lipid transport from gut to lymph. Tissue Cell 2021; 72:101529. [PMID: 33915359 DOI: 10.1016/j.tice.2021.101529] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 02/26/2021] [Accepted: 03/11/2021] [Indexed: 12/14/2022]
Abstract
Although the general structure of the barrier between the gut and the blood is well known, many details are still missing. Here, we analyse the literature and our own data related to lipid transcytosis through adult mammalian enterocytes, and their absorption into lymph at the tissue level of the intestine. After starvation, the Golgi complex (GC) of enterocytes is in a resting state. The addition of lipids in the form of chyme leads to the initial appearance of pre-chylomicrons (ChMs) in the tubules of the smooth endoplasmic reticulum, which are attached at the basolateral plasma membrane, immediately below the 'belt' of the adhesive junctions. Then pre-ChMs move into the cisternae of the rough endoplasmic reticulum and then into the expansion of the perforated Golgi cisternae. Next, they pass through the GC, and are concentrated in the distensions of the perforated cisternae on the trans-side of the GC. The arrival of pre-ChMs at the GC leads to the transition of the GC to a state of active transport, with formation of intercisternal connections, attachment of cis-most and trans-most perforated cisternae to the medial Golgi cisternae, and disappearance of COPI vesicles. Post-Golgi carriers then deliver ChMs to the basolateral plasma membrane, fuse with it, and secret ChMs into the intercellular space between enterocytes at the level of their interdigitating contacts. Finally, ChMs are squeezed out into the interstitium through pores in the basal membrane, most likely due to the function of the actin-myosin 'cuff' around the interdigitating contacts. These pores appear to be formed by protrusions of the dendritic cells and the enterocytes per se. ChMs are absorbed from the interstitium into the lymphatic capillaries through the special oblique contacts between endothelial cells, which function as valves through the contraction-relaxation of bundles of smooth muscle cells in the interstitium. Lipid overloading of enterocytes results in accumulation of cytoplasmic lipid droplets, an increase in diameter of ChMs, inhibition of intra-Golgi transport, and fusion of ChMs in the interstitium. Here, we summarise and analyse recent findings, and discuss their functional implications.
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Affiliation(s)
- Irina S Sesorova
- Department of Anatomy, Saint Petersburg State Paediatric Medical University, S. Petersburg, Russia
| | - Ivan D Dimov
- Department of Anatomy, Ivanovo State Medical Academy, Ivanovo, Russia
| | - Alexandre D Kashin
- Department of Anatomy, Saint Petersburg State Paediatric Medical University, S. Petersburg, Russia
| | - Vitaly V Sesorov
- Department of Anatomy, Saint Petersburg State Paediatric Medical University, S. Petersburg, Russia
| | | | - Maria A Zdorikova
- Department of Anatomy, Saint Petersburg State Paediatric Medical University, S. Petersburg, Russia
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22
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Lutkewitte AJ, Singer JM, Shew TM, Martino MR, Hall AM, He M, Finck BN. Multiple antisense oligonucleotides targeted against monoacylglycerol acyltransferase 1 (Mogat1) improve glucose metabolism independently of Mogat1. Mol Metab 2021; 49:101204. [PMID: 33676028 PMCID: PMC8027266 DOI: 10.1016/j.molmet.2021.101204] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 02/17/2021] [Accepted: 03/01/2021] [Indexed: 01/14/2023] Open
Abstract
OBJECTIVE Monoacylglycerol acyltransferase (MGAT) enzymes catalyze the synthesis of diacylglycerol from monoacylglycerol. Previous work has suggested the importance of MGAT activity in the development of obesity-related hepatic insulin resistance. Indeed, antisense oligonucleotide (ASO)-mediated knockdown of Mogat1 mRNA, which encodes MGAT1, reduced hepatic MGAT activity and improved glucose tolerance and insulin resistance in high-fat diet (HFD)-fed mice. However, recent work has suggested that some ASOs may have off-target effects on body weight and metabolic parameters via activation of the interferon alpha/beta receptor 1 (IFNAR-1) pathway. METHODS Mice with whole-body Mogat1 knockout or a floxed allele for Mogat1 to allow for liver-specific Mogat1-knockout (by either a liver-specific transgenic or adeno-associated virus-driven Cre recombinase) were generated. These mice were placed on an HFD, and glucose metabolism and insulin sensitivity were assessed after 16 weeks on diet. In some experiments, mice were treated with control scramble or Mogat1 ASOs in the presence or absence of IFNAR-1 neutralizing antibody. RESULTS Genetic deletion of hepatic Mogat1, either acutely or chronically, did not improve hepatic steatosis, glucose tolerance, or insulin sensitivity in HFD-fed mice. Furthermore, constitutive Mogat1 knockout in all tissues actually exacerbated HFD-induced obesity, insulin sensitivity, and glucose intolerance on an HFD. Despite markedly reduced Mogat1 expression, liver MGAT activity was unaffected in all knockout mouse models. Mogat1 overexpression in hepatocytes increased liver MGAT activity and TAG content in low-fat-fed mice but did not cause insulin resistance. Multiple Mogat1 ASO sequences improved glucose tolerance in both wild-type and Mogat1 null mice, suggesting an off-target effect. Hepatic IFNAR-1 signaling was activated by multiple Mogat1 ASOs, but its blockade did not prevent the effects of either Mogat1 ASO on glucose homeostasis. CONCLUSION These results indicate that genetic loss of Mogat1 does not affect hepatic MGAT activity or metabolic homeostasis on HFD and show that multiple Mogat1 ASOs improve glucose metabolism through effects independent of targeting Mogat1 or activation of IFNAR-1 signaling.
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Affiliation(s)
- Andrew J Lutkewitte
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States
| | - Jason M Singer
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States
| | - Trevor M Shew
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States
| | - Michael R Martino
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States
| | - Angela M Hall
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States
| | - Mai He
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, United States
| | - Brian N Finck
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States.
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23
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Sphingomyelin synthase-related protein generates diacylglycerol via the hydrolysis of glycerophospholipids in the absence of ceramide. J Biol Chem 2021; 296:100454. [PMID: 33621517 PMCID: PMC7988496 DOI: 10.1016/j.jbc.2021.100454] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 02/16/2021] [Accepted: 02/19/2021] [Indexed: 01/20/2023] Open
Abstract
Diacylglycerol (DG) is a well-established lipid second messenger. Sphingomyelin synthase (SMS)-related protein (SMSr) produces DG and ceramide phosphoethanolamine (CPE) by the transfer of phosphoethanolamine from phosphatidylethanolamine (PE) to ceramide. We previously reported that human SMSr overexpressed in COS-7 cells significantly increased DG levels, particularly saturated and/or monounsaturated fatty acid-containing DG molecular species, and provided DG to DG kinase (DGK) δ, which regulates various pathophysiological events, including epidermal growth factor-dependent cell proliferation, type 2 diabetes, and obsessive-compulsive disorder. However, mammalian SMSr puzzlingly produces only trace amounts of CPE/DG. To clarify this discrepancy, we highly purified SMSr and examined its activities other than CPE synthase. Intriguingly, purified SMSr showed a DG-generating activity via hydrolysis of PE, phosphatidic acid (PA), phosphatidylinositol (PI), and phosphatidylcholine (PC) in the absence of ceramide. DG generation through the PA phosphatase (PAP) activity of SMSr was approximately 300-fold higher than that with PE and ceramide. SMSr hydrolyzed PI ten times stronger than PI(4,5)bisphosphate (PI(4,5)P2). The PAP and PC-phospholipase C (PLC) activities of SMSr were inhibited by propranolol, a PAP inhibitor, and by D609, an SMS/PC-PLC inhibitor. Moreover, SMSr showed substrate selectivity for saturated and/or monounsaturated fatty acid-containing PA molecular species, but not arachidonic-acid-containing PA, which is exclusively generated in the PI(4,5)P2 cycle. We confirmed that SMSr expressed in COS-7 cells showed PAP and PI-PLC activities. Taken together, our study indicated that SMSr possesses previously unrecognized enzyme activities, PAP and PI/PE/PC-PLC, and constitutes a novel DG/PA signaling pathway together with DGKδ, which is independent of the PI(4,5)P2 cycle.
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24
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Levy E, Beaulieu JF, Spahis S. From Congenital Disorders of Fat Malabsorption to Understanding Intra-Enterocyte Mechanisms Behind Chylomicron Assembly and Secretion. Front Physiol 2021; 12:629222. [PMID: 33584351 PMCID: PMC7873531 DOI: 10.3389/fphys.2021.629222] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 01/06/2021] [Indexed: 11/13/2022] Open
Abstract
During the last two decades, a large body of information on the events responsible for intestinal fat digestion and absorption has been accumulated. In particular, many groups have extensively focused on the absorptive phase in order to highlight the critical "players" and the main mechanisms orchestrating the assembly and secretion of chylomicrons (CM) as essential vehicles of alimentary lipids. The major aim of this article is to review understanding derived from basic science and clinical conditions associated with impaired packaging and export of CM. We have particularly insisted on inborn metabolic pathways in humans as well as on genetically modified animal models (recapitulating pathological features). The ultimate goal of this approach is that "experiments of nature" and in vivo model strategy collectively allow gaining novel mechanistic insight and filling the gap between the underlying genetic defect and the apparent clinical phenotype. Thus, uncovering the cause of disease contributes not only to understanding normal physiologic pathway, but also to capturing disorder onset, progression, treatment and prognosis.
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Affiliation(s)
- Emile Levy
- Research Centre, CHU Ste-Justine, Université de Montréal, Montreal, QC, Canada
- Department of Nutrition, Université de Montréal, Montreal, QC, Canada
- Department of Pediatrics, Université de Montréal, Montreal, QC, Canada
| | - Jean François Beaulieu
- Laboratory of Intestinal Physiopathology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Schohraya Spahis
- Research Centre, CHU Ste-Justine, Université de Montréal, Montreal, QC, Canada
- Department of Nutrition, Université de Montréal, Montreal, QC, Canada
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25
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Singh Y, Datey A, Chakravortty D, Tumaney AW. Novel Cell-Based Assay to Investigate Monoacylglycerol Acyltransferase 2 Inhibitory Activity Using HIEC-6 Cell Line. ACS OMEGA 2021; 6:1732-1740. [PMID: 33490832 PMCID: PMC7818593 DOI: 10.1021/acsomega.0c05950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 12/23/2020] [Indexed: 06/12/2023]
Abstract
The dietary triacylglycerol (TAG) gets absorbed and accumulated in the body through the monoacylglycerol (MAG) pathway, which plays a major role in obesity and related disorders. The main enzyme of this pathway, monoacylglycerol acyltransferase 2 (MGAT2), is considered as a potential target for developing antiobesity compounds. Hence, there is a need for in vitro cell-based assays for screening the potential leads for MGAT2 inhibitors. Because of synthetic inhibitor's side effects, there is an increased interest in natural extracts as potential leads. Hence, we have optimized a 2-MAG-induced TAG accumulation inhibitory cell-based assay to screen natural extracts using the HIEC-6 cell line. A concentration-dependent TAG accumulation was observed when the HIEC-6 cells were fed with exogenous 2-MAG. The TAG accumulation was confirmed by in situ BODIPY staining and was quantified. However, no TAG accumulation was seen when the cells were fed with exogenous DAG or TAG, suggesting MGAT2-mediated MAG uptake and its conversion to TAG. We demonstrated the utility of this assay by screening five different plant-based aqueous extracts. These extracts showed various inhibition levels (25% to 30%) of 2-MAG-induced TAG accumulation in the HIEC-6. The MGAT2 inhibitory potential of these extracts was confirmed by an in vitro MGAT2 assay. This cell-based assay adds a new methodology for screening, developing, and evaluating MGAT2 inhibitors for addressing obesity and related disorders.
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Affiliation(s)
- Yeshvanthi Singh
- Academy
of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
- Department
of Lipid Science, Council of Scientific
and Industrial Research−Central Food Technological Research
Institute, Mysuru 570 020, India
| | - Akshay Datey
- Department
of Microbiology and Cell Biology, Indian
Institute of Science, Bangalore 560012, India
| | - Dipshikha Chakravortty
- Department
of Microbiology and Cell Biology, Indian
Institute of Science, Bangalore 560012, India
| | - Ajay W. Tumaney
- Academy
of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
- Department
of Lipid Science, Council of Scientific
and Industrial Research−Central Food Technological Research
Institute, Mysuru 570 020, India
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26
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Sato Y. Development of Lipid Nanoparticles for the Delivery of Macromolecules Based on the Molecular Design of pH-Sensitive Cationic Lipids. Chem Pharm Bull (Tokyo) 2021; 69:1141-1159. [PMID: 34853281 DOI: 10.1248/cpb.c21-00705] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Considerable efforts have been made on the development of lipid nanoparticles (LNPs) for delivering of nucleic acids in LNP-based medicines, including a first-ever short interfering RNA (siRNA) medicine, Onpattro, and the mRNA vaccines against the coronavirus disease 2019 (COVID-19), which have been approved and are currently in use worldwide. The successful rational design of ionizable cationic lipids was a major breakthrough that dramatically increased delivery efficiency in this field. The LNPs would be expected to be useful as a platform technology for the delivery of various therapeutic modalities for genome editing and even for undiscovered therapeutic mechanisms. In this review, the current progress of my research, including the molecular design of pH-sensitive cationic lipids, their applications for various tissues and cell types, and for delivering various macromolecules, including siRNA, antisense oligonucleotide, mRNA, and the clustered regularly interspaced short palindromic repeats (CRISPR)-associated (Cas) system will be described. Mechanistic studies regarding relationships between the physicochemical properties of LNPs, drug delivery, and biosafety are also summarized. Furthermore, current issues that need to be addressed for next generation drug delivery systems are discussed.
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Affiliation(s)
- Yusuke Sato
- Faculty of Pharmaceutical Sciences, Hokkaido University
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27
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Human adipocyte differentiation and composition of disease-relevant lipids are regulated by miR-221-3p. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1866:158841. [PMID: 33075494 DOI: 10.1016/j.bbalip.2020.158841] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 10/07/2020] [Accepted: 10/11/2020] [Indexed: 12/15/2022]
Abstract
MicroRNA-221-3p (miR-221-3p) is associated with both metabolic diseases and cancers. However, its role in terminal adipocyte differentiation and lipid metabolism are uncharacterized. miR-221-3p or its inhibitor was transfected into differentiating or mature human adipocytes. Triglyceride (TG) content and adipogenic gene expression were monitored, global lipidome analysis was carried out, and mechanisms underlying the effects of miR-221-3p were investigated. Finally, cross-talk between miR-221-3p expressing adipocytes and MCF-7 breast carcinoma (BC) cells was studied, and miR-221-3p expression in tumor-proximal adipose biopsies from BC patients analyzed. miR-221-3p overexpression inhibited terminal differentiation of adipocytes, as judged from reduced TG storage and gene expression of the adipogenic markers SCD1, GLUT4, FAS, DGAT1/2, AP2, ATGL and AdipoQ, whereas the miR-221-3p inhibitor increased TG storage. Knockdown of the predicted miR-221-3p target, 14-3-3γ, had similar antiadipogenic effects as miR-221-3p overexpression, indicating it as a potential mediator of mir-221-3p function. Importantly, miR-221-3p overexpression inhibited de novo lipogenesis but increased the concentrations of ceramides and sphingomyelins, while reducing diacylglycerols, concomitant with suppression of sphingomyelin phosphodiesterase, ATP citrate lyase, and acid ceramidase. miR-221-3p expression was elevated in tumor proximal adipose tissue from patients with invasive BC. Conditioned medium of miR-221-3p overexpressing adipocytes stimulated the invasion and proliferation of BC cells, while medium of the BC cells enhanced miR-221-3p expression in adipocytes. Elevated miR-221-3p impairs adipocyte lipid storage and differentiation, and modifies their ceramide, sphingomyelin, and diacylglycerol content. These alterations are relevant for metabolic diseases but may also affect cancer progression.
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28
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Genetic effects of MOGAT1 gene SNP in growth traits of Chinese cattle. Gene 2020; 769:145201. [PMID: 33035617 DOI: 10.1016/j.gene.2020.145201] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 09/25/2020] [Accepted: 09/29/2020] [Indexed: 11/21/2022]
Abstract
Single nucleotide polymorphism (SNP) has recently become one of the ideal genetic markers. SNP refers to the DNA sequence polymorphism caused by double nucleotide variation in the genome, including the conversion or transversion of segmented bases. The synthesis and metabolism of triglycerides are related to the changes of energy in the body of livestock, which in turn affects their growth and development. Studies have shown that MOGAT1 gene plays a role in the route of triglyceride synthesis. PCR-RFLP and agarose gel electrophoresis technology were used to type the SNP site of MOGAT1 gene at g.25940T > C in this study. Association analysis between typing results and growth trait data was detected by SPSS 20.0 software. Results show that MOGAT1 gene was in a low level of heterozygosity in Xianan, Qinchuan and Pinan cattle population (0 < PIC < 0.25), and in middle level of heterozygosity in YL cattle population(0.25 < PIC < 0.5). And genotype 'AA' was dominant gene in Chinese cattle population. In QC and XN cattle, genotype of GG possess advantage on Body weight (P < 0.05); in YL cattle, individuals with genotype of homozygous mutation decreased significantly on Chest depth (P < 0.05). The purpose of this research is to provide theoretical materials for molecular breeding of yellow cattle and to promote the process of improving the growth traits of Chinese local yellow cattle.
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29
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Carlson JC, Weeks DE, Hawley NL, Sun G, Cheng H, Naseri T, Reupena MS, Tuitele J, Deka R, McGarvey ST, Minster RL. Genome-wide association studies in Samoans give insight into the genetic architecture of fasting serum lipid levels. J Hum Genet 2020; 66:111-121. [PMID: 32759990 DOI: 10.1038/s10038-020-0816-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 07/16/2020] [Accepted: 07/20/2020] [Indexed: 11/09/2022]
Abstract
The current understanding of the genetic architecture of lipids has largely come from genome-wide association studies (GWAS). To date, few GWAS have examined the genetic architecture of lipids in Polynesians, and none have in Samoans, whose unique population history, including many population bottlenecks, may provide insight into the biological foundations of variation in lipid levels. Here we performed a GWAS of four fasting serum lipid levels: total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL), and triglycerides (TG) in a sample of 2849 Samoans, with validation genotyping for associations in a replication cohort comprising 1798 Samoans and American Samoans. We identified multiple genome-wide significant associations (P < 5 × 10-8) previously seen in other populations-APOA1 with TG, CETP with HDL, and APOE with TC and LDL-and several suggestive associations (P < 1 × 10-5), including an association of variants downstream of MGAT1 and RAB21 with HDL. However, we observed different association signals for variants near APOE than what has been previously reported in non-Polynesian populations. The association with several known lipid loci combined with the newly identified associations with variants near MGAT1 and RAB21 suggest that while some of the genetic architecture of lipids is shared between Samoans and other populations, part of the genetic architecture may be Polynesian-specific.
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Affiliation(s)
- Jenna C Carlson
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Biostatistics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Daniel E Weeks
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Biostatistics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Nicola L Hawley
- Department of Chronic Disease Epidemiology, Yale School of Public Health, New Haven, CT, USA
| | - Guangyun Sun
- Department of Environmental Health, College of Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - Hong Cheng
- Department of Environmental Health, College of Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - Take Naseri
- Ministry of Health, Government of Samoa, Apia, Samoa
| | | | - John Tuitele
- Department of Public Health, Government of American Samoa, Pago Pago, AS, USA
| | - Ranjan Deka
- Department of Environmental Health, College of Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - Stephen T McGarvey
- International Health Institute and Department of Epidemiology, School of Public Health, Brown University, Providence, RI, USA.,Department of Anthropology, Brown University, Providence, RI, USA
| | - Ryan L Minster
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA.
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30
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Tanaka M, Ishikawa T, Tamura S, Saito Y, Kawai-Yamada M, Hihara Y. Quantitative and Qualitative Analyses of Triacylglycerol Production in the Wild-Type Cyanobacterium Synechocystis sp. PCC 6803 and the Strain Expressing AtfA from Acinetobacter baylyi ADP1. ACTA ACUST UNITED AC 2020; 61:1537-1547. [DOI: 10.1093/pcp/pcaa069] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 05/12/2020] [Indexed: 12/24/2022]
Abstract
Abstract
Although cyanobacteria do not possess wax ester synthase/acyl-CoA:diacylglycerol acyltransferase (WS/DGAT), the bacterial enzyme for triacylglycerol (TAG) production, there have been several studies reporting the accumulation of TAG-like compounds in cyanobacteria. In this study, we aimed to evaluate TAG productivity of the ΔrecJ::atfA strain of Synechocystis sp. PCC 6803 generated by inserting atfA encoding WS/DGAT from Acinetobacter baylyi ADP1 into recJ (sll1354), together with the wild type (WT) and the gene-disrupted strain of slr2103 having homology with eukaryotic DGAT2 gene family (Δ2103). Thin-layer chromatography (TLC) of neutral lipids or isolation of the neutral lipid-enriched fraction followed by gas chromatography or liquid chromatography–tandem mass spectrometry was employed for analyses. The ΔrecJ::atfA strain accumulated 0.508 nmol ml−1OD730−1 of TAG after a week of incubation at 100 μmol photons m−2 s−1. The saturated fatty acids C16:0 and C18:0 accounted for about 50% and 20% of the TAG fatty acids, respectively, suggesting that de novo-synthesized fatty acids were preferentially incorporated into TAG molecules. When the neutral lipid profile of the lipid extracts was examined by TLC, a spot located in a slightly lower position compared with the TAG standard was detected in WT but not in the Δ2103 strain. TAG accumulation levels of both strains was only 0.01–0.03 nmol ml−1OD730−1, but the fatty acid composition was substantially different from that of the background. These results suggest that trace amounts of TAG can be produced in Synechocystis cells by enzymes other than Slr2103, and major constituents of the TAG-like spot are unknown lipid species produced by Slr2103.
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Affiliation(s)
- Motoki Tanaka
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, Saitama, 338-8570 Japan
| | - Toshiki Ishikawa
- Department of Environmental Science and Technology, Graduate School of Science and Engineering, Saitama University, Saitama, 338-8570 Japan
| | - So Tamura
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, Saitama, 338-8570 Japan
| | - Yujiro Saito
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, Saitama, 338-8570 Japan
| | - Maki Kawai-Yamada
- Department of Environmental Science and Technology, Graduate School of Science and Engineering, Saitama University, Saitama, 338-8570 Japan
| | - Yukako Hihara
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, Saitama, 338-8570 Japan
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31
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Monoacylglycerol Form of Omega-3s Improves Its Bioavailability in Humans Compared to Other Forms. Nutrients 2020; 12:nu12041014. [PMID: 32272659 PMCID: PMC7230359 DOI: 10.3390/nu12041014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/31/2020] [Accepted: 04/02/2020] [Indexed: 12/11/2022] Open
Abstract
Numerous benefits are attributed to omega-3 fatty acids (OM3) especially in cardiovascular health. However, bioavailability and clinical efficacy depend on numerous factors, including OM3 form, food matrix effects (especially the lipid content of the diet), and metabolic capacity. Here, we show in humans that a "pre-digested" OM3-sn-1(3)-monoacylglycerol lipid structure (OM3-MAG) has a significantly greater absorption at high therapeutic doses (2.9 g/day) than the most commonly OM3-ethyl ester (3.1 g/day) form (used for the treatment of hypertriglyceridemia), and a comparable profile to other pre-digested OM3 free fatty acids (OM3-FFA) structure (3.2 g/day). Nutritional supplement doses of MAG resulted in similar increases in OM3 blood level, compared to OM3 triacylglycerols (OM3-TAG) supplements in obese subjects (1.2 g/day) under low fat diet, and in children with cystic fibrosis (1.0 g/day). These results suggest that both forms of pre-digested OM3-MAG and OM3-FFA are effectively absorbed and re-incorporated effectively into triacylglycerols inside the enterocytes, before being exported into the chylomicrons lipid transport system. The pre-digested OM3-MAG might provide a more effective therapy in severe cardiovascular conditions where high doses of OM3 are required and a low-fat diet is indicated, which limited digestive lipase activity.
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32
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Lutkewitte AJ, McCommis KS, Schweitzer GG, Chambers KT, Graham MJ, Wang L, Patti GJ, Hall AM, Finck BN. Hepatic monoacylglycerol acyltransferase 1 is induced by prolonged food deprivation to modulate the hepatic fasting response. J Lipid Res 2019; 60:528-538. [PMID: 30610082 PMCID: PMC6399500 DOI: 10.1194/jlr.m089722] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 12/05/2018] [Indexed: 01/14/2023] Open
Abstract
During prolonged fasting, the liver plays a central role in maintaining systemic energy homeostasis by producing glucose and ketones in processes fueled by oxidation of fatty acids liberated from adipose tissue. In mice, this is accompanied by transient hepatic accumulation of glycerolipids. We found that the hepatic expression of monoacylglycerol acyltransferase 1 (Mogat1), an enzyme with monoacylglycerol acyltransferase (MGAT) activity that produces diacyl-glycerol from monoacylglycerol, was significantly increased in the liver of fasted mice compared with mice given ad libitum access to food. Basal and fasting-induced expression of Mogat1 was markedly diminished in the liver of mice lacking the transcription factor PPARα. Suppressing Mogat1 expression in liver and adipose tissue with antisense oligonucleotides (ASOs) reduced hepatic MGAT activity and triglyceride content compared with fasted controls. Surprisingly, the expression of many other PPARα target genes and PPARα activity was also decreased in mice given Mogat1 ASOs. When mice treated with control or Mogat1 ASOs were gavaged with the PPARα ligand, WY-14643, and then fasted for 18 h, WY-14643 administration reversed the effects of Mogat1 ASOs on PPARα target gene expression and liver triglyceride content. In conclusion, Mogat1 is a fasting-induced PPARα target gene that may feed forward to regulate liver PPARα activity during food deprivation.
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Affiliation(s)
- Andrew J Lutkewitte
- Center for Human Nutrition Washington University School of Medicine, St. Louis, MO
| | - Kyle S McCommis
- Center for Human Nutrition Washington University School of Medicine, St. Louis, MO
| | - George G Schweitzer
- Center for Human Nutrition Washington University School of Medicine, St. Louis, MO
| | - Kari T Chambers
- Center for Human Nutrition Washington University School of Medicine, St. Louis, MO
| | | | - Lingjue Wang
- Department of Chemistry, Washington University, St. Louis, MO
| | - Gary J Patti
- Department of Chemistry, Washington University, St. Louis, MO
- Department of Medicine, Washington University School of Medicine, St. Louis, MO
| | - Angela M Hall
- Center for Human Nutrition Washington University School of Medicine, St. Louis, MO
| | - Brian N Finck
- Center for Human Nutrition Washington University School of Medicine, St. Louis, MO
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Even İ, Akiva İ, İyison NB. An in vivo RNAi mini-screen in Drosophila cancer models reveals novel potential Wnt targets in liver cancer. TURKISH JOURNAL OF GASTROENTEROLOGY 2018; 30:198-207. [PMID: 30541713 DOI: 10.5152/tjg.2018.18241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND/AIMS Aberrant activation of the Wnt/β-catenin signaling, which arises from the accumulation of mutant β-catenin in the cell, is one of the most common driving forces in hepatocellular carcinoma (HCC). We previously identified several genes that are regulated on the overexpression of β-catenin in the HCC cell line that are suggested to be novel Wnt/β-catenin targets playing effective roles in cancer. The aim of the present study was to elucidate the roles of these putative target genes in tumorigenesis with an in vivo analysis in Drosophila. MATERIALS AND METHODS We selected 15 genes downregulated in two Drosophila cancer models. RESULTS The results from the RNAi mini-screen revealed novel roles for the analyzed putative Wnt/β-catenin target genes in tumorigenesis. The downregulation of the analyzed nine genes led to tumor formation as well as metastasis in Drosophila, suggesting a tumor suppressor function. On the other hand, the knockdown of the other two genes suppressed tumor and metastasis formations and disturbed the development of the analyzed eye tissues, indicating an oncogenic or developmental role for these genes. CONCLUSION These findings could serve to identify novel subjects for cancer research in order to provide insight into the diagnostic and therapeutic processes of several cancer types.
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Affiliation(s)
- İpek Even
- Department of Molecular Biology and Genetics, Boğaziçi University, İstanbul, Turkey
| | - İzzet Akiva
- Department of Molecular Biology and Genetics, Boğaziçi University, İstanbul, Turkey
| | - Necla Birgül İyison
- Department of Molecular Biology and Genetics, Boğaziçi University, İstanbul, Turkey;Center for Life Sciences and Technologies, Boğaziçi University, İstanbul, Turkey
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Hernández-Corbacho MJ, Obeid LM. A novel role for DGATs in cancer. Adv Biol Regul 2018; 72:89-101. [PMID: 30579761 DOI: 10.1016/j.jbior.2018.12.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 12/09/2018] [Accepted: 12/10/2018] [Indexed: 02/06/2023]
Affiliation(s)
- María José Hernández-Corbacho
- Stony Brook Cancer Center and the Department of Medicine, Stony Brook University, Health Sciences Center, Stony Brook, NY, 11794, USA
| | - Lina M Obeid
- Stony Brook Cancer Center and the Department of Medicine, Stony Brook University, Health Sciences Center, Stony Brook, NY, 11794, USA; The Northport VA Medical Center, Northport, NY, 11768, USA.
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35
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Pabst B, Futatsugi K, Li Q, Ahn K. Mechanistic Characterization of Long Residence Time Inhibitors of Diacylglycerol Acyltransferase 2 (DGAT2). Biochemistry 2018; 57:6997-7010. [DOI: 10.1021/acs.biochem.8b01096] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Bhatt-Wessel B, Jordan TW, Miller JH, Peng L. Role of DGAT enzymes in triacylglycerol metabolism. Arch Biochem Biophys 2018; 655:1-11. [PMID: 30077544 DOI: 10.1016/j.abb.2018.08.001] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 07/25/2018] [Accepted: 08/02/2018] [Indexed: 01/22/2023]
Abstract
The esterification of a fatty acyl moiety to diacylglycerol to form triacylglycerol (TAG) is catalysed by two diacylglycerol O-acyltransferases (DGATs) encoded by genes belonging to two distinct gene families. The enzymes are referred to as DGAT1 and DGAT2 in order of their identification. Both proteins are transmembrane proteins localized in the endoplasmic reticulum. Their membrane topologies are however significantly different. This difference is hypothesized to give the two isozymes different abilities to interact with other proteins and organelles and access to different pools of fatty acids, thereby creating a distinction between the enzymes in terms of their role and contribution to lipid metabolism. DGAT1 is proposed to have dual topology contributing to TAG synthesis on both sides of the ER membrane and esterifying only the pre-formed fatty acids. There is evidence to suggest that DGAT2 translocates to the lipid droplet (LD), associates with other proteins, and synthesizes cytosolic and luminal apolipoprotein B associated LD-TAG from both endogenous and exogenous fatty acids. The aim of this review is to differentiate between the two DGAT enzymes by comparing the genes that encode them, their proposed topologies, the proteins they interact with, and their roles in lipid metabolism.
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Affiliation(s)
- Bhumika Bhatt-Wessel
- Centre for Biodiscovery and School of Biological Sciences, Victoria University of Wellington, New Zealand
| | - T William Jordan
- Centre for Biodiscovery and School of Biological Sciences, Victoria University of Wellington, New Zealand
| | - John H Miller
- Centre for Biodiscovery and School of Biological Sciences, Victoria University of Wellington, New Zealand
| | - Lifeng Peng
- Centre for Biodiscovery and School of Biological Sciences, Victoria University of Wellington, New Zealand.
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37
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Devasthale P, Cheng D. Monoacylglycerol Acyltransferase 2 (MGAT2) Inhibitors for the Treatment of Metabolic Diseases and Nonalcoholic Steatohepatitis (NASH). J Med Chem 2018; 61:9879-9888. [PMID: 29986142 DOI: 10.1021/acs.jmedchem.8b00864] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Monoacylglycerol transferase 2 (MGAT2) is a pivotal enzyme in the monoacylglycerol pathway for triacylglycerol synthesis. The pathway for triacylglycerol synthesis has provided several attractive targets for drug discovery in the treatment of metabolic diseases. Marketed drugs that inhibit enzymes in this pathway include orlistat (pancreatic lipase inhibitor), lomitapide (mitochondrial transfer protein inhibitor), and mipomersen (apolipoprotein B synthesis inhibitor), but poor gastrointestinal (GI) tolerability or safety considerations have limited their use and indications. In addition, several inhibitors of diacylglycerol transferase 1 (DGAT1) have advanced to the clinic but were withdrawn due to poor GI tolerability. This report first discusses the biological rationale in support of inhibition of MGAT2 as a therapeutic approach that may offer a distinct and superior efficacy versus GI tolerability profile and then reviews advances in the discovery of small molecule MGAT2 inhibitors for the treatment of metabolic diseases and nonalcoholic steatohepatitis (NASH).
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38
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Liss KHH, Lutkewitte AJ, Pietka T, Finck BN, Franczyk M, Yoshino J, Klein S, Hall AM. Metabolic importance of adipose tissue monoacylglycerol acyltransferase 1 in mice and humans. J Lipid Res 2018; 59:1630-1639. [PMID: 29853530 PMCID: PMC6121930 DOI: 10.1194/jlr.m084947] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 05/10/2018] [Indexed: 12/31/2022] Open
Abstract
Adipocyte triglyceride storage provides a reservoir of energy that allows the organism to survive times of nutrient scarcity, but excessive adiposity has emerged as a health problem in many areas of the world. Monoacylglycerol acyltransferase (MGAT) acylates monoacylglycerol to produce diacylglycerol; the penultimate step in triglyceride synthesis. However, little is known about MGAT activity in adipocytes, which are believed to rely primarily on another pathway for triglyceride synthesis. We show that expression of the gene that encodes MGAT1 is robustly induced during adipocyte differentiation and that its expression is suppressed in fat of genetically-obese mice and metabolically-abnormal obese human subjects. Interestingly, MGAT1 expression is also reduced in physiologic contexts where lipolysis is high. Moreover, knockdown or knockout of MGAT1 in adipocytes leads to higher rates of basal adipocyte lipolysis. Collectively, these data suggest that MGAT1 activity may play a role in regulating basal adipocyte FFA retention.
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Affiliation(s)
- Kim H H Liss
- Department of Pediatrics Washington University School of Medicine, St. Louis, MO 63110
| | | | - Terri Pietka
- Medicine, Washington University School of Medicine, St. Louis, MO 63110
| | - Brian N Finck
- Medicine, Washington University School of Medicine, St. Louis, MO 63110
| | - Michael Franczyk
- Medicine, Washington University School of Medicine, St. Louis, MO 63110
| | - Jun Yoshino
- Medicine, Washington University School of Medicine, St. Louis, MO 63110
| | - Samuel Klein
- Medicine, Washington University School of Medicine, St. Louis, MO 63110
| | - Angela M Hall
- Medicine, Washington University School of Medicine, St. Louis, MO 63110.
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Ramon-Krauel M, Pentinat T, Bloks VW, Cebrià J, Ribo S, Pérez-Wienese R, Vilà M, Palacios-Marin I, Fernández-Pérez A, Vallejo M, Téllez N, Rodríguez MÀ, Yanes O, Lerin C, Díaz R, Plosch T, Tietge UJF, Jimenez-Chillaron JC. Epigenetic programming at the Mogat1 locus may link neonatal overnutrition with long-term hepatic steatosis and insulin resistance. FASEB J 2018; 32:fj201700717RR. [PMID: 29812971 DOI: 10.1096/fj.201700717rr] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Postnatal overfeeding increases the risk of chronic diseases later in life, including obesity, insulin resistance, hepatic steatosis, and type 2 diabetes. Epigenetic mechanisms might underlie the long-lasting effects associated with early nutrition. Here we aimed to explore the molecular pathways involved in early development of insulin resistance and hepatic steatosis, and we examined the potential contribution of DNA methylation and histone modifications to long-term programming of metabolic disease. We used a well-characterized mouse model of neonatal overfeeding and early adiposity by litter size reduction. Neonatal overfeeding led to hepatic insulin resistance very early in life that persisted throughout adulthood despite normalizing food intake. Up-regulation of monoacylglycerol O-acyltransferase ( Mogat) 1 conceivably mediates hepatic steatosis and insulin resistance through increasing intracellular diacylglycerol content. Early and sustained deregulation of Mogat1 was associated with a combination of histone modifications that might favor Mogat1 expression. In sum, postnatal overfeeding causes extremely rapid derangements of hepatic insulin sensitivity that remain relatively stable until adulthood. Epigenetic mechanisms, particularly histone modifications, could contribute to such long-lasting effects. Our data suggest that targeting hepatic monoacylglycerol acyltransferase activity during early life might provide a novel strategy to improve hepatic insulin sensitivity and prevent late-onset insulin resistance and fatty liver disease.-Ramon-Krauel, M., Pentinat, T., Bloks, V. W., Cebrià, J., Ribo, S., Pérez-Wienese, R., Vilà, M., Palacios-Marin, I., Fernández-Pérez, A., Vallejo, M., Téllez, N., Rodríguez, M. À., Yanes, O., Lerin, C., Díaz, R., Plosch, T., Tietge, U. J. F., Jimenez-Chillaron, J. C. Epigenetic programming at the Mogat1 locus may link neonatal overnutrition with long-term hepatic steatosis and insulin resistance.
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Affiliation(s)
- Marta Ramon-Krauel
- Endocrinology Department, Institut de Recerca Sant Joan de Déu, Esplugues, Barcelona, Spain
| | - Thais Pentinat
- Endocrinology Department, Institut de Recerca Sant Joan de Déu, Esplugues, Barcelona, Spain
| | - Vincent W Bloks
- Department of Pediatrics, Section of Molecular Metabolism and Nutrition, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Judith Cebrià
- Endocrinology Department, Institut de Recerca Sant Joan de Déu, Esplugues, Barcelona, Spain
| | - Silvia Ribo
- Endocrinology Department, Institut de Recerca Sant Joan de Déu, Esplugues, Barcelona, Spain
| | - Ricky Pérez-Wienese
- Endocrinology Department, Institut de Recerca Sant Joan de Déu, Esplugues, Barcelona, Spain
| | - Maria Vilà
- Endocrinology Department, Institut de Recerca Sant Joan de Déu, Esplugues, Barcelona, Spain
| | - Ivonne Palacios-Marin
- Endocrinology Department, Institut de Recerca Sant Joan de Déu, Esplugues, Barcelona, Spain
| | - Antonio Fernández-Pérez
- Ciber de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas y Universidad Autónoma de Madrid (CSIC/UAM), Madrid, Spain
| | - Mario Vallejo
- Ciber de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas y Universidad Autónoma de Madrid (CSIC/UAM), Madrid, Spain
| | - Noèlia Téllez
- Ciber de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
- Bellvitge Biomedical Research Institute (IDIBELL) L'Hospitalet, Barcelona, Spain
| | - Miguel Àngel Rodríguez
- Ciber de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
- Department of Electronic Engineering, Universitat Rovira i Virgili, Tarragona, Spain
| | - Oscar Yanes
- Ciber de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
- Department of Electronic Engineering, Universitat Rovira i Virgili, Tarragona, Spain
| | - Carles Lerin
- Endocrinology Department, Institut de Recerca Sant Joan de Déu, Esplugues, Barcelona, Spain
| | - Rubén Díaz
- Endocrinology Department, Institut de Recerca Sant Joan de Déu, Esplugues, Barcelona, Spain
| | - Torsten Plosch
- Department of Obstetrics and Gynaecology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Uwe J F Tietge
- Department of Pediatrics, Section of Molecular Metabolism and Nutrition, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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Lee YJ, Kim JW. Monoacylglycerol O-acyltransferase 1 (MGAT1) localizes to the ER and lipid droplets promoting triacylglycerol synthesis. BMB Rep 2018; 50:367-372. [PMID: 28347400 PMCID: PMC5584744 DOI: 10.5483/bmbrep.2017.50.7.036] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Indexed: 01/14/2023] Open
Abstract
Monoacylglycerol acyltransferase 1 (MGAT) is a microsomal enzyme that catalyzes the synthesis of diacylglycerol (DAG) and triacylglycerol (TAG). However, the subcellular localization and catalytic function domain of this enzyme is poorly understood. In this report, we identified that murine MGAT1 localizes to the endoplasmic reticulum (ER) under normal conditions, whereas MGAT1 co-localize to the lipid droplets (LD) under conditions of enriching fatty acids, contributing to TAG synthesis and LD expansion. For the enzyme activity, both the N-terminal transmembrane domain and catalytic HPHG motif are required. We also show that the transmembrane domain of MGAT1 consists of two hydrophobic regions in the N-terminus, and the consensus sequence FLXLXXXn, a putative neutral lipid-binding domain, exists in the first transmembrane domain. Finally, MGAT1 interacts with DGAT2, which serves to synergistically increase the TAG biosynthesis and LD expansion, leading to enhancement of lipid accumulation in the liver and fat.
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Affiliation(s)
- Yoo Jeong Lee
- Division of Metabolic Disease, Center for Biomedical Sciences, National Institutes of Health, Cheongju 28159, Korea
| | - Jae-Woo Kim
- Department of Biochemistry and Molecular Biology, Integrated Genomic Research Center for Metabolic Regulation, Institute of Genetic Science, Yonsei University College of Medicine; Brain Korea 21 PLUS Project for Medical Science, Yonsei University; Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 03722, Korea
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41
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Korber M, Klein I, Daum G. Steryl ester synthesis, storage and hydrolysis: A contribution to sterol homeostasis. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:1534-1545. [DOI: 10.1016/j.bbalip.2017.09.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 08/25/2017] [Accepted: 09/05/2017] [Indexed: 02/01/2023]
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Abstract
Lipid droplets (LDs) are ubiquitous organelles that store neutral lipids for energy or membrane synthesis and act as hubs for metabolic processes. Cells generate LDs de novo, converting cells to emulsions with LDs constituting the dispersed oil phase in the aqueous cytoplasm. Here we review our current view of LD biogenesis. We present a model of LD formation from the ER in distinct steps and highlight the biology of proteins that govern this biophysical process. Areas of incomplete knowledge are identified, as are connections with physiology and diseases linked to alterations in LD biology.
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Affiliation(s)
- Tobias C Walther
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115; , .,Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115.,Broad Institute of Harvard and MIT, Cambridge, Massachusetts 02142.,Howard Hughes Medical Institute, Boston, Massachusetts 02115
| | - Jeeyun Chung
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115; , .,Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115
| | - Robert V Farese
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115; , .,Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115.,Broad Institute of Harvard and MIT, Cambridge, Massachusetts 02142
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43
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How lipid droplets "TAG" along: Glycerolipid synthetic enzymes and lipid storage. Biochim Biophys Acta Mol Cell Biol Lipids 2017. [PMID: 28642195 DOI: 10.1016/j.bbalip.2017.06.010] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Triacylglycerols (TAG) serve as the predominant form of energy storage in mammalian cells, and TAG synthesis influences conditions such as obesity, fatty liver, and insulin resistance. In most tissues, the glycerol 3-phosphate pathway enzymes are responsible for TAG synthesis, and the regulation and function of these enzymes is therefore important for metabolic homeostasis. Here we review the sites and regulation of glycerol-3-phosphate acyltransferase (GPAT), acylglycerol-3-phosphate acyltransferase (AGPAT), lipin phosphatidic acid phosphatase (PAP), and diacylglycerol acyltransferase (DGAT) enzyme action. We highlight the critical roles that these enzymes play in human health by reviewing Mendelian disorders that result from mutation in the corresponding genes. We also summarize the valuable insights that genetically engineered mouse models have provided into the cellular and physiological roles of GPATs, AGPATs, lipins and DGATs. Finally, we comment on the status and feasibility of therapeutic approaches to metabolic disease that target enzymes of the glycerol 3-phosphate pathway. This article is part of a Special Issue entitled: Recent Advances in Lipid Droplet Biology edited by Rosalind Coleman and Matthijs Hesselink.
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44
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Ma Z, Onorato JM, Chen L, Nelson DW, Yen CLE, Cheng D. Synthesis of neutral ether lipid monoalkyl-diacylglycerol by lipid acyltransferases. J Lipid Res 2017; 58:1091-1099. [PMID: 28420705 DOI: 10.1194/jlr.m073445] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 04/14/2017] [Indexed: 12/29/2022] Open
Abstract
In mammals, ether lipids exert a wide spectrum of signaling and structural functions, such as stimulation of immune responses, anti-tumor activities, and enhancement of sperm functions. Abnormal accumulation of monoalkyl-diacylglycerol (MADAG) was found in Wolman's disease, a human genetic disorder defined by a deficiency in lysosomal acid lipase. In the current study, we found that among the nine recombinant human lipid acyltransferases examined, acyl-CoA:diacylglycerol acyltransferase (DGAT)1, DGAT2, acyl-CoA:monoacylglycerol acyltransferase (MGAT)2, MGAT3, acyl-CoA:wax-alcohol acyltransferase 2/MFAT, and DGAT candidate 3 were able to use 1-monoalkylglycerol (1-MAkG) as an acyl acceptor for the synthesis of monoalkyl-monoacylglycerol (MAMAG). These enzymes demonstrated different enzymatic turnover rates and relative efficiencies for the first and second acylation steps leading to the synthesis of MAMAG and MADAG, respectively. They also exhibited different degrees of substrate preference when presented with 1-monooleoylglycerol versus 1-MAkG. In CHO-K1 cells, treatment with DGAT1 selective inhibitor, XP-620, completely blocked the synthesis of MADAG, indicating that DGAT1 is the predominant enzyme responsible for the intracellular synthesis of MADAG in this model system. The levels of MADAG in the adrenal gland of DGAT1 KO mice were reduced as compared with those of the WT mice, suggesting that DGAT1 is a major enzyme for the synthesis of MADAG in this tissue. Our findings indicate that several of these lipid acyltransferases may be able to synthesize neutral ether lipids in mammals.
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Affiliation(s)
- Zhengping Ma
- Departments of Fibrosis Discovery Bristol-Myers Squibb Company, Princeton, NJ 08543-5400
| | - Joelle M Onorato
- Bioanalytical and Discovery Analytical Sciences, Research and Development, Bristol-Myers Squibb Company, Princeton, NJ 08543-5400
| | - Luping Chen
- Departments of Fibrosis Discovery Bristol-Myers Squibb Company, Princeton, NJ 08543-5400
| | - David W Nelson
- Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI 53706
| | - Chi-Liang Eric Yen
- Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI 53706
| | - Dong Cheng
- Departments of Fibrosis Discovery Bristol-Myers Squibb Company, Princeton, NJ 08543-5400
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Fan LYN, Saavedra-García P, Lam EWF. Dataset of the human homologues and orthologues of lipid-metabolic genes identified as DAF-16 targets their roles in lipid and energy metabolism. Data Brief 2017; 11:606-610. [PMID: 28349111 PMCID: PMC5358523 DOI: 10.1016/j.dib.2017.02.055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 02/08/2017] [Accepted: 02/28/2017] [Indexed: 12/18/2022] Open
Abstract
The data presented in this article are related to the review article entitled ‘Unravelling the role of fatty acid metabolism in cancer through the FOXO3-FOXM1 axis’ (Saavedra-Garcia et al., 2017) [24]. Here, we have matched the DAF-16/FOXO3 downstream genes with their respective human orthologues and reviewed the roles of these targeted genes in FA metabolism. The list of genes listed in this article are precisely selected from literature reviews based on their functions in mammalian FA metabolism. The nematode Caenorhabditis elegans gene orthologues of the genes are obtained from WormBase, the online biological database of C. elegans. This dataset has not been uploaded to a public repository yet.
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Key Words
- ACAA2, Acetyl-CoA acetyltransferase 2
- ACACA, Acetyl-CoA carboxylase
- ACAD8, Acyl-CoA dehydrogenase family member 8
- ACADM, Acyl-CoA dehydrogenase C4 to C12 straight chain
- ACOX, Acyl-CoA oxidase
- ACSL3/4, Acyl-CoA synthetase long-chain family member 3/4
- ACSS, Acyl-CoA synthetase short-chain family member
- CPT2, Carnitine palmitoyltransferase II
- Caenorhabditis elegans
- DAF-16
- DAG, Diacylglycerol
- DGAT, Diacylglycerol O-acyltransferase
- ECHS1, Short-chain enoyl-CoA hydratase 1
- ELOVL1, Elongation of very long chain fatty acids protein 1
- FA, fatty acid
- FADS2, Fatty acid desaturase 2
- FASN, Fatty acid synthase
- FATP4, Fatty acid transport protein 4
- FOX, Forkhead box
- FOXM1
- FOXO3
- HADH, Hydroxyacyl-coenzyme A dehydrogenase
- HADHA, Hydroxyacyl-CoA dehydrogenase/3-Ketoacyl-CoA thiolase/Enoyl-CoA hydratase, alpha subunit
- LCFA, Long chain fatty acid
- Lipid metabolism
- MLYCD, Malonyl-CoA decarboxylase
- MOGAT1/2, Monoacylglycerol O-acyltransferase 1/2
- PNPLA, patatin like phospholipase domain containing
- PUFA, polyunsaturated fatty acid
- SCD1/5, Stearoyl-CoA desaturase 1/5
- TAG, triacylglycerol
- TCA, Tricarboxylic acid
- VLCFA, Very long chain fatty acid.
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Grabner GF, Zimmermann R, Schicho R, Taschler U. Monoglyceride lipase as a drug target: At the crossroads of arachidonic acid metabolism and endocannabinoid signaling. Pharmacol Ther 2017; 175:35-46. [PMID: 28213089 DOI: 10.1016/j.pharmthera.2017.02.033] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Monoglyerides (MGs) are short-lived, intermediary lipids deriving from the degradation of phospho- and neutral lipids, and monoglyceride lipase (MGL), also designated as monoacylglycerol lipase (MAGL), is the major enzyme catalyzing the hydrolysis of MGs into glycerol and fatty acids. This distinct function enables MGL to regulate a number of physiological and pathophysiological processes since both MGs and fatty acids can act as signaling lipids or precursors thereof. The most prominent MG species acting as signaling lipid is 2-arachidonoyl glycerol (2-AG) which is the most abundant endogenous agonist of cannabinoid receptors in the body. Importantly, recent observations demonstrate that 2-AG represents a quantitatively important source for arachidonic acid, the precursor of prostaglandins and other inflammatory mediators. Accordingly, MGL-mediated 2-AG degradation affects lipid signaling by cannabinoid receptor-dependent and independent mechanisms. Recent genetic and pharmacological studies gave important insights into MGL's role in (patho-)physiological processes, and the enzyme is now considered as a promising drug target for a number of disorders including cancer, neurodegenerative and inflammatory diseases. This review summarizes the basics of MG (2-AG) metabolism and provides an overview on the therapeutic potential of MGL.
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Affiliation(s)
- Gernot F Grabner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Robert Zimmermann
- Institute of Molecular Biosciences, University of Graz, Graz, Austria; BioTechMed Graz, Graz, Austria
| | - Rudolf Schicho
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria; BioTechMed Graz, Graz, Austria.
| | - Ulrike Taschler
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
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Wolf Greenstein A, Majumdar N, Yang P, Subbaiah PV, Kineman RD, Cordoba-Chacon J. Hepatocyte-specific, PPARγ-regulated mechanisms to promote steatosis in adult mice. J Endocrinol 2017; 232:107-121. [PMID: 27799461 PMCID: PMC5120553 DOI: 10.1530/joe-16-0447] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 10/25/2016] [Indexed: 12/15/2022]
Abstract
Peroxisome proliferator-activated receptor γ (PPARγ) is the target for thiazolidinones (TZDs), drugs that improve insulin sensitivity and fatty liver in humans and rodent models, related to a reduction in hepatic de novo lipogenesis (DNL). The systemic effects of TZDs are in contrast to reports suggesting hepatocyte-specific activation of PPARγ promotes DNL, triacylglycerol (TAG) uptake and fatty acid (FA) esterification. As these hepatocyte-specific effects of PPARγ could counterbalance the positive therapeutic actions of systemic delivery of TZDs, the current study used a mouse model of adult-onset, liver (hepatocyte)-specific PPARγ knockdown (aLivPPARγkd). This model has advantages over existing congenital knockout models, by avoiding compensatory changes related to embryonic knockdown, thus better modeling the impact of altering PPARγ on adult physiology, where metabolic diseases most frequently develop. The impact of aLivPPARγkd on hepatic gene expression and endpoints in lipid metabolism was examined after 1 or 18 weeks (Chow-fed) or after 14 weeks of low- or high-fat (HF) diet. aLivPPARγkd reduced hepatic TAG content but did not impact endpoints in DNL or TAG uptake. However, aLivPPARγkd reduced the expression of the FA translocase (Cd36), in 18-week Chow- and HF-fed mice, associated with increased NEFA after HF feeding. Also, aLivPPARγkd dramatically reduced Mogat1 expression, that was reflected by an increase in hepatic monoacylglycerol (MAG) levels, indicative of reduced MOGAT activity. These results, coupled with previous reports, suggest that Cd36-mediated FA uptake and MAG pathway-mediated FA esterification are major targets of hepatocyte PPARγ, where loss of this control explains in part the protection against steatosis observed after aLivPPARγkd.
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Affiliation(s)
- Abigail Wolf Greenstein
- Research and Development DivisionJesse Brown Veterans Affairs Medical Center, Chicago, Illinois, USA
- Section of EndocrinologyDiabetes, and Metabolism, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA
- Biologic Resources LaboratoryUniversity of Illinois at Chicago, Chicago, Illinois, USA
| | - Neena Majumdar
- Research and Development DivisionJesse Brown Veterans Affairs Medical Center, Chicago, Illinois, USA
- Section of EndocrinologyDiabetes, and Metabolism, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Peng Yang
- Research and Development DivisionJesse Brown Veterans Affairs Medical Center, Chicago, Illinois, USA
- Section of EndocrinologyDiabetes, and Metabolism, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Papasani V Subbaiah
- Research and Development DivisionJesse Brown Veterans Affairs Medical Center, Chicago, Illinois, USA
- Section of EndocrinologyDiabetes, and Metabolism, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Rhonda D Kineman
- Research and Development DivisionJesse Brown Veterans Affairs Medical Center, Chicago, Illinois, USA
- Section of EndocrinologyDiabetes, and Metabolism, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Jose Cordoba-Chacon
- Research and Development DivisionJesse Brown Veterans Affairs Medical Center, Chicago, Illinois, USA
- Section of EndocrinologyDiabetes, and Metabolism, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA
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48
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Diacylglycerol acyltransferase-2 and monoacylglycerol acyltransferase-2 are ubiquitinated proteins that are degraded by the 26S proteasome. Biochem J 2016; 473:3621-3637. [DOI: 10.1042/bcj20160418] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 08/16/2016] [Indexed: 01/20/2023]
Abstract
Acyl-CoA:1,2-diacylglycerol acyltransferase (DGAT)-2 is one of the two DGAT enzymes that catalyzes the synthesis of triacylglycerol, which is an important form of stored energy for eukaryotic organisms. There is currently limited information available regarding how DGAT2 and triacylglycerol synthesis are regulated. Recent studies have indicated that DGAT2 can be regulated by changes in gene expression. How DGAT2 is regulated post-transcriptionally remains less clear. In this study, we demonstrated that DGAT2 is a very unstable protein and is rapidly degraded in an ubiquitin-dependent manner via the proteasome. Many of the 25 lysines present in DGAT2 appeared to be involved in promoting its degradation. However, the six C-terminal lysines were the most important in regulating stability. We also demonstrated that acyl-CoA:monoacylglycerol acyltransferase (MGAT)-2, an enzyme with extensive sequence homology to DGAT2 that catalyzes the synthesis of diacylglycerol, was also ubiquitinated. However, MGAT2 was found to be much more stable than DGAT2. Interestingly, when co-expressed, MGAT2 appeared to stabilize DGAT2. Finally, we found that both DGAT2 and MGAT2 are substrates of the endoplasmic reticulum-associated degradation pathway.
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49
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Sankella S, Garg A, Agarwal AK. Characterization of the Mouse and Human Monoacylglycerol O-Acyltransferase 1 (Mogat1) Promoter in Human Kidney Proximal Tubule and Rat Liver Cells. PLoS One 2016; 11:e0162504. [PMID: 27611931 PMCID: PMC5017789 DOI: 10.1371/journal.pone.0162504] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 08/23/2016] [Indexed: 12/22/2022] Open
Abstract
Monoacylglycerol acyltransferase 1 (Mogat1) catalyzes the conversion of monoacylglycerols (MAG) to diacylglycerols (DAG), the precursor of several physiologically important lipids such as phosphatidylcholine, phosphatidylethanolamine and triacylglycerol (TAG). Expression of Mogat1 is tissue restricted and it is highly expressed in the kidney, stomach and adipose tissue but minimally in the normal adult liver. To understand the transcriptional regulation of Mogat1, we characterized the mouse and human Mogat1 promoters in human kidney proximal tubule-2 (HK-2) cells. In-silico analysis revealed several peroxisome proliferator response element (PPRE) binding sites in the promoters of both human and mouse Mogat1. These sites responded to all three peroxisome proliferator activated receptor (PPAR) isoforms such that their respective agonist or antagonist activated or inhibited the expression of Mogat1. PPRE site mutagenesis revealed that sites located at -592 and -2518 are very effective in decreasing luciferase reporter gene activity. Chromatin immunoprecipitation (ChIP) assay using PPARα antibody further confirmed the occupancy of these sites by PPARα. While these assays revealed the core promoter elements necessary for Mogat1 expression, there are additional elements required to regulate its tissue specific expression. Chromosome conformation capture (3C) assay revealed additional cis-elements located ~10–15 kb upstream which interact with the core promoter. These chromosomal regions are responsive to both PPARα agonist and antagonist.
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Affiliation(s)
- Shireesha Sankella
- Division of Nutrition and Metabolic Diseases, Department of Internal Medicine and Center for Human Nutrition, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390, United States of America
| | - Abhimanyu Garg
- Division of Nutrition and Metabolic Diseases, Department of Internal Medicine and Center for Human Nutrition, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390, United States of America
| | - Anil K. Agarwal
- Division of Nutrition and Metabolic Diseases, Department of Internal Medicine and Center for Human Nutrition, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390, United States of America
- * E-mail:
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50
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Yu JH, Song SJ, Kim A, Choi Y, Seok JW, Kim HJ, Lee YJ, Lee KS, Kim JW. Suppression of PPARγ-mediated monoacylglycerol O-acyltransferase 1 expression ameliorates alcoholic hepatic steatosis. Sci Rep 2016; 6:29352. [PMID: 27404390 PMCID: PMC4941543 DOI: 10.1038/srep29352] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 06/16/2016] [Indexed: 12/20/2022] Open
Abstract
Alcohol consumption is one of the major causes of hepatic steatosis, fibrosis, cirrhosis, and superimposed hepatocellular carcinoma. Ethanol metabolism alters the NAD(+)/NADH ratio, thereby suppressing the activity of sirtuin family proteins, which may affect lipid metabolism in liver cells. However, it is not clear how long-term ingestion of ethanol eventually causes lipid accumulation in liver. Here, we demonstrate that chronic ethanol ingestion activates peroxisome proliferator-activated receptor γ (PPARγ) and its target gene, monoacylglycerol O-acyltransferase 1 (MGAT1). During ethanol metabolism, a low NAD(+)/NADH ratio repressed NAD-dependent deacetylase sirtuin 1 (SIRT1) activity, concomitantly resulting in increased acetylated PPARγ with high transcriptional activity. Accordingly, SIRT1 transgenic mice exhibited a low level of acetylated PPARγ and were protected from hepatic steatosis driven by alcohol or PPARγ2 overexpression, suggesting that ethanol metabolism causes lipid accumulation through activation of PPARγ through acetylation. Among the genes induced by PPARγ upon alcohol consumption, MGAT1 has been shown to be involved in triglyceride synthesis. Thus, we tested the effect of MGAT1 knockdown in mice following ethanol consumption, and found a significant reduction in alcohol-induced hepatic lipid accumulation. These results suggest that MGAT1 may afford a promising approach to the treatment of fatty liver disease.
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Affiliation(s)
- Jung Hwan Yu
- Department of Biochemistry and Molecular Biology, Integrated Genomic Research Center for Metabolic Regulation, Institute of Genetic Science, Yonsei University College of Medicine, Seoul 120-752, Korea.,Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul 120-752, Korea
| | - Su Jin Song
- Department of Biochemistry and Molecular Biology, Integrated Genomic Research Center for Metabolic Regulation, Institute of Genetic Science, Yonsei University College of Medicine, Seoul 120-752, Korea.,Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul 120-752, Korea
| | - Ara Kim
- Department of Biochemistry and Molecular Biology, Integrated Genomic Research Center for Metabolic Regulation, Institute of Genetic Science, Yonsei University College of Medicine, Seoul 120-752, Korea.,Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul 120-752, Korea
| | - Yoonjeong Choi
- Department of Biochemistry and Molecular Biology, Integrated Genomic Research Center for Metabolic Regulation, Institute of Genetic Science, Yonsei University College of Medicine, Seoul 120-752, Korea.,Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul 120-752, Korea
| | - Jo Woon Seok
- Department of Biochemistry and Molecular Biology, Integrated Genomic Research Center for Metabolic Regulation, Institute of Genetic Science, Yonsei University College of Medicine, Seoul 120-752, Korea.,Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul 120-752, Korea
| | - Hyo Jung Kim
- Department of Biochemistry and Molecular Biology, Integrated Genomic Research Center for Metabolic Regulation, Institute of Genetic Science, Yonsei University College of Medicine, Seoul 120-752, Korea
| | - Yoo Jeong Lee
- Division of Metabolic Disease, Center for Biomedical Sciences, National Institutes of Health, Cheongwon-gun, Chungbuk 363-951, Korea
| | - Kwan Sik Lee
- Department of Internal Medicine, Yonsei University College of Medicine, Seoul 120-752, Korea
| | - Jae-Woo Kim
- Department of Biochemistry and Molecular Biology, Integrated Genomic Research Center for Metabolic Regulation, Institute of Genetic Science, Yonsei University College of Medicine, Seoul 120-752, Korea.,Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul 120-752, Korea.,Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 120-752, Korea
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