401
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Yang T, Wen Y, Li J, Tan T, Yang J, Pan J, Hu C, Yao Y, Zhang J, Li S, Xia H, He J, Zou Y. Association of CMYC polymorphisms with hepatoblastoma risk. Transl Cancer Res 2020; 9:849-855. [PMID: 35117430 PMCID: PMC8798278 DOI: 10.21037/tcr.2019.12.19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 11/26/2019] [Indexed: 02/05/2023]
Abstract
BACKGROUND Single-nucleotide polymorphisms (SNPs) in genes may affect gene expression and contribute to cancer susceptibility. This study aimed to explore the association between CMYC gene polymorphisms and hepatoblastoma risk. METHODS Hepatoblastoma patients and cancer-free controls were recruited and matched by age and sex. Genotypes were determined by TaqMan, and the strength of the association of interest was determined by calculating odds ratios (ORs) and 95% confidence intervals (CIs). The distributions of various CMYC genotypes among subjects were recorded, followed by analyses of associations between CMYC polymorphisms and hepatoblastoma risk. RESULTS A total of 213 hepatoblastoma patients and 958 cancer-free controls were enrolled. No significant associations between the CMYC rs4645943 and rs2070583 polymorphisms and hepatoblastoma risk were found (all P>0.05). In stratification analysis based on age, sex, and clinical stage, the CMYC rs4645943 and rs2070583 polymorphisms were not associated with hepatoblastoma susceptibility (all P>0.05). CONCLUSIONS Thus, the CMYC rs4645943 and rs2070583 polymorphisms were not associated with hepatoblastoma risk in the study cohort.
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Affiliation(s)
- Tianyou Yang
- Department of Pediatric Surgery, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou 510623, China
| | - Yang Wen
- First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China
| | - Jiahao Li
- Department of Pediatric Surgery, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou 510623, China
| | - Tianbao Tan
- Department of Pediatric Surgery, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou 510623, China
| | - Jiliang Yang
- Department of Pediatric Surgery, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou 510623, China
| | - Jing Pan
- Department of Pediatric Surgery, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou 510623, China
| | - Chao Hu
- Department of Pediatric Surgery, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou 510623, China
| | - Yuxiao Yao
- Department of Pediatric Surgery, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou 510623, China
| | - Jiao Zhang
- Department of Pediatric Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
| | - Suhong Li
- Department of Pathology, Children Hospital and Women Health Center of Shanxi, Taiyuan 030002, China
| | - Huimin Xia
- Department of Pediatric Surgery, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou 510623, China
| | - Jing He
- Department of Pediatric Surgery, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou 510623, China
| | - Yan Zou
- Department of Pediatric Surgery, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou 510623, China
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402
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Virani SS, Alonso A, Benjamin EJ, Bittencourt MS, Callaway CW, Carson AP, Chamberlain AM, Chang AR, Cheng S, Delling FN, Djousse L, Elkind MSV, Ferguson JF, Fornage M, Khan SS, Kissela BM, Knutson KL, Kwan TW, Lackland DT, Lewis TT, Lichtman JH, Longenecker CT, Loop MS, Lutsey PL, Martin SS, Matsushita K, Moran AE, Mussolino ME, Perak AM, Rosamond WD, Roth GA, Sampson UKA, Satou GM, Schroeder EB, Shah SH, Shay CM, Spartano NL, Stokes A, Tirschwell DL, VanWagner LB, Tsao CW. Heart Disease and Stroke Statistics-2020 Update: A Report From the American Heart Association. Circulation 2020; 141:e139-e596. [PMID: 31992061 DOI: 10.1161/cir.0000000000000757] [Citation(s) in RCA: 4861] [Impact Index Per Article: 1215.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND The American Heart Association, in conjunction with the National Institutes of Health, annually reports on the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs). METHODS The American Heart Association, through its Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update. The 2020 Statistical Update is the product of a full year's worth of effort by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. This year's edition includes data on the monitoring and benefits of cardiovascular health in the population, metrics to assess and monitor healthy diets, an enhanced focus on social determinants of health, a focus on the global burden of cardiovascular disease, and further evidence-based approaches to changing behaviors, implementation strategies, and implications of the American Heart Association's 2020 Impact Goals. RESULTS Each of the 26 chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics. CONCLUSIONS The Statistical Update represents a critical resource for the lay public, policy makers, media professionals, clinicians, healthcare administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.
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403
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Öztürk Z, O’Kane CJ, Pérez-Moreno JJ. Axonal Endoplasmic Reticulum Dynamics and Its Roles in Neurodegeneration. Front Neurosci 2020; 14:48. [PMID: 32116502 PMCID: PMC7025499 DOI: 10.3389/fnins.2020.00048] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 01/13/2020] [Indexed: 12/13/2022] Open
Abstract
The physical continuity of axons over long cellular distances poses challenges for their maintenance. One organelle that faces this challenge is endoplasmic reticulum (ER); unlike other intracellular organelles, this forms a physically continuous network throughout the cell, with a single membrane and a single lumen. In axons, ER is mainly smooth, forming a tubular network with occasional sheets or cisternae and low amounts of rough ER. It has many potential roles: lipid biosynthesis, glucose homeostasis, a Ca2+ store, protein export, and contacting and regulating other organelles. This tubular network structure is determined by ER-shaping proteins, mutations in some of which are causative for neurodegenerative disorders such as hereditary spastic paraplegia (HSP). While axonal ER shares many features with the tubular ER network in other contexts, these features must be adapted to the long and narrow dimensions of axons. ER appears to be physically continuous throughout axons, over distances that are enormous on a subcellular scale. It is therefore a potential channel for long-distance or regional communication within neurons, independent of action potentials or physical transport of cargos, but involving its physiological roles such as Ca2+ or organelle homeostasis. Despite its apparent stability, axonal ER is highly dynamic, showing features like anterograde and retrograde transport, potentially reflecting continuous fusion and breakage of the network. Here we discuss the transport processes that must contribute to this dynamic behavior of ER. We also discuss the model that these processes underpin a homeostatic process that ensures both enough ER to maintain continuity of the network and repair breaks in it, but not too much ER that might disrupt local cellular physiology. Finally, we discuss how failure of ER organization in axons could lead to axon degenerative diseases, and how a requirement for ER continuity could make distal axons most susceptible to degeneration in conditions that disrupt ER continuity.
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Affiliation(s)
| | - Cahir J. O’Kane
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
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404
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Gu L, Zhu Y, Lin X, Tan X, Lu B, Li Y. Stabilization of FASN by ACAT1-mediated GNPAT acetylation promotes lipid metabolism and hepatocarcinogenesis. Oncogene 2020; 39:2437-2449. [PMID: 31974474 DOI: 10.1038/s41388-020-1156-0] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 12/24/2019] [Accepted: 01/10/2020] [Indexed: 11/09/2022]
Abstract
Metabolic alteration for adaptation of the local environment has been recognized as a hallmark of cancer. GNPAT dysregulation has been implicated in hepatocellular carcinoma (HCC). However, the precise posttranslational regulation of GNPAT is still undiscovered. Here we show that ACAT1 is upregulated in response to extra palmitic acid (PA). ACAT1 acetylates GNPAT at K128, which represses TRIM21-mediated GNPAT ubiquitination and degradation. Conversely, GNPAT deacetylation by SIRT4 antagonizes ACAT1's function. GNPAT represses TRIM21-mediated FASN degradation and promotes lipid metabolism. Furthermore, shRNA-mediated ACAT1 ablation and acetylation deficiency of GNPAT repress lipid metabolism and tumor progression in xenograft and DEN/CCl4-induced HCC. Otherwise, ACAT1 inhibitor combination with sorafenib enormously retards tumor formation in mice. Collectively, we demonstrate that stabilization of FASN by ACAT1-mediated GNPAT acetylation plays a critical role in hepatocarcinogenesis.
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Affiliation(s)
- Li Gu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China. .,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, 430071, China.
| | - Yahui Zhu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, 430071, China
| | - Xi Lin
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, 430071, China
| | - Xingyu Tan
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, 430071, China
| | - Bingjun Lu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, 430071, China
| | - Youjun Li
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China. .,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, 430071, China.
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405
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Abstract
PURPOSE OF REVIEW Our review provides a brief summary of the most recent advances towards the identification of the genetic basis of specific aspects of obesity and the quantification of their consequences on health. We also highlight the most promising avenues to be explored in the future. RECENT FINDINGS While obesity has been demonstrated to lead to adverse cardio-metabolic consequences, the determinants of inter-individual variability remain largely unknown. The elucidation of the molecular underpinnings of this relationship is hampered by the extremely heterogeneous nature of obesity as a human trait. Recent technological advances have facilitated a more in-depth characterization of body composition at large-scale. At the pace of current data acquisition and resolution, it is realistic to improve characterization of obesity and to advise individuals based on detailed body composition combined with tissue-specific molecular signatures. Individualized predictions of health implications would enable more personalized and effective public health interventions.
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Affiliation(s)
- Jonathan Sulc
- Institute for Primary Care and Public Health, University of Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Thomas W Winkler
- Department of Genetic Epidemiology, University of Regensburg, Regensburg, Germany
| | - Iris M Heid
- Department of Genetic Epidemiology, University of Regensburg, Regensburg, Germany
| | - Zoltán Kutalik
- Institute for Primary Care and Public Health, University of Lausanne, Lausanne, Switzerland.
- Swiss Institute of Bioinformatics, Lausanne, Switzerland.
- Genetics of Complex Traits, University of Exeter Medical School, University of Exeter, Exeter, UK.
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406
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Løvsletten NG, Vu H, Skagen C, Lund J, Kase ET, Thoresen GH, Zammit VA, Rustan AC. Treatment of human skeletal muscle cells with inhibitors of diacylglycerol acyltransferases 1 and 2 to explore isozyme-specific roles on lipid metabolism. Sci Rep 2020; 10:238. [PMID: 31937853 PMCID: PMC6959318 DOI: 10.1038/s41598-019-57157-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 12/19/2019] [Indexed: 12/30/2022] Open
Abstract
Diacylglycerol acyltransferases (DGAT) 1 and 2 catalyse the final step in triacylglycerol (TAG) synthesis, the esterification of fatty acyl-CoA to diacylglycerol. Despite catalysing the same reaction and being present in the same cell types, they exhibit different functions on lipid metabolism in various tissues. Yet, their roles in skeletal muscle remain poorly defined. In this study, we investigated how selective inhibitors of DGAT1 and DGAT2 affected lipid metabolism in human primary skeletal muscle cells. The results showed that DGAT1 was dominant in human skeletal muscle cells utilizing fatty acids (FAs) derived from various sources, both exogenously supplied FA, de novo synthesised FA, or FA derived from lipolysis, to generate TAG, as well as being involved in de novo synthesis of TAG. On the other hand, DGAT2 seemed to be specialised for de novo synthesis of TAG from glycerol-3-posphate only. Interestingly, DGAT activities were also important for regulating FA oxidation, indicating a key role in balancing FAs between storage in TAG and efficient utilization through oxidation. Finally, we observed that inhibition of DGAT enzymes could potentially alter glucose-FA interactions in skeletal muscle. In summary, treatment with DGAT1 or DGAT2 specific inhibitors resulted in different responses on lipid metabolism in human myotubes, indicating that the two enzymes play distinct roles in TAG metabolism in skeletal muscle.
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Affiliation(s)
- Nils G Løvsletten
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway
| | - Helene Vu
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway
| | - Christine Skagen
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway
| | - Jenny Lund
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway
| | - Eili T Kase
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway
| | - G Hege Thoresen
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway.,Department of Pharmacology, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Victor A Zammit
- Division of Translational and Experimental medicine, Warwick Medical School, University of Warwick, Coventry, UK
| | - Arild C Rustan
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway.
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407
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Butler AA, Graham JL, Stanhope KL, Wong S, King S, Bremer AA, Krauss RM, Hamilton J, Havel PJ. Role of angiopoietin-like protein 3 in sugar-induced dyslipidemia in rhesus macaques: suppression by fish oil or RNAi. J Lipid Res 2020; 61:376-386. [PMID: 31919051 DOI: 10.1194/jlr.ra119000423] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 01/07/2020] [Indexed: 02/07/2023] Open
Abstract
Angiopoietin-like protein 3 (ANGPTL3) inhibits lipid clearance and is a promising target for managing cardiovascular disease. Here we investigated the effects of a high-sugar (high-fructose) diet on circulating ANGPTL3 concentrations in rhesus macaques. Plasma ANGPTL3 concentrations increased ∼30% to 40% after 1 and 3 months of a high-fructose diet (both P < 0.001 vs. baseline). During fructose-induced metabolic dysregulation, plasma ANGPTL3 concentrations were positively correlated with circulating indices of insulin resistance [assessed with fasting insulin and the homeostatic model assessment of insulin resistance (HOMA-IR)], hypertriglyceridemia, adiposity (assessed as leptin), and systemic inflammation [C-reactive peptide (CRP)] and negatively correlated with plasma levels of the insulin-sensitizing hormone adropin. Multiple regression analyses identified a strong association between circulating APOC3 and ANGPTL3 concentrations. Higher baseline plasma levels of both ANGPTL3 and APOC3 were associated with an increased risk for fructose-induced insulin resistance. Fish oil previously shown to prevent insulin resistance and hypertriglyceridemia in this model prevented increases of ANGPTL3 without affecting systemic inflammation (increased plasma CRP and interleukin-6 concentrations). ANGPTL3 RNAi lowered plasma concentrations of ANGPTL3, triglycerides (TGs), VLDL-C, APOC3, and APOE. These decreases were consistent with a reduced risk of atherosclerosis. In summary, dietary sugar-induced increases of circulating ANGPTL3 concentrations after metabolic dysregulation correlated positively with leptin levels, HOMA-IR, and dyslipidemia. Targeting ANGPTL3 expression with RNAi inhibited dyslipidemia by lowering plasma TGs, VLDL-C, APOC3, and APOE levels in rhesus macaques.
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Affiliation(s)
- Andrew A Butler
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, MO
| | - James L Graham
- Department of Molecular Biosciences, University of California, Davis, Davis, CA.,School of Veterinary Medicine, California National Primate Research Center, and Department of Nutrition, University of California, Davis, Davis, CA
| | - Kimber L Stanhope
- Department of Molecular Biosciences, University of California, Davis, Davis, CA.,School of Veterinary Medicine, California National Primate Research Center, and Department of Nutrition, University of California, Davis, Davis, CA
| | - So Wong
- Arrowhead Pharmaceuticals, Pasadena, CA
| | - Sarah King
- Children's Hospital Oakland Research Institute, Oakland, CA
| | - Andrew A Bremer
- Department of Pediatrics, Vanderbilt University, Nashville, TN
| | | | | | - Peter J Havel
- Department of Molecular Biosciences, University of California, Davis, Davis, CA .,School of Veterinary Medicine, California National Primate Research Center, and Department of Nutrition, University of California, Davis, Davis, CA
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408
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Bagias C, Xiarchou A, Bargiota A, Tigas S. Familial Partial Lipodystrophy (FPLD): Recent Insights. Diabetes Metab Syndr Obes 2020; 13:1531-1544. [PMID: 32440182 PMCID: PMC7224169 DOI: 10.2147/dmso.s206053] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 03/31/2020] [Indexed: 12/16/2022] Open
Abstract
Lipodystrophies are a heterogeneous group of congenital or acquired disorders, characterized by partial or generalized loss of adipose tissue. Familial partial lipodystrophy (FPLD) presents with genetic and phenotypic variability with insulin resistance, hypertriglyceridemia and hepatic steatosis being the cardinal metabolic features. The severity of the metabolic derangements is in proportion with the degree of lipoatrophy. The underpinning pathogenetic mechanism is the limited capacity of adipose tissue to store lipids leading to lipotoxicity, low-grade inflammation, altered adipokine secretion and ectopic fat tissue accumulation. Advances in molecular genetics have led to the discovery of new genes and improved our knowledge of the regulation of adipose tissue biology. Diagnosis relies predominantly on clinical findings, such as abnormal fat tissue topography and signs of insulin resistance and is confirmed by genetic analysis. In addition to anthropometry and conventional imaging, new techniques such as color-coded imaging of fat depots allow more accurate assessment of the regional fat distribution and differentiation of lipodystrophic syndromes from common metabolic syndrome phenotype. The treatment of patients with lipodystrophy has proven to be challenging. The use of a human leptin analogue, metreleptin, has recently been approved in the management of FPLD with evidence suggesting improved metabolic profile, satiety, reproductive function and self-perception. Preliminary data on the use of glucagon-like peptide 1 receptor agonists (GLP1 Ras) and sodium-glucose co-transporter 2 (SGLT2) inhibitors in cases of FPLD have shown promising results with reduction in total insulin requirements and improvement in glycemic control. Finally, investigational trials for new therapeutic agents in the management of FPLD are underway.
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Affiliation(s)
- Christos Bagias
- Department of Endocrinology, University of Ioannina, Ioannina, Greece
| | - Angeliki Xiarchou
- Department of Endocrinology, University of Ioannina, Ioannina, Greece
| | | | - Stelios Tigas
- Department of Endocrinology, University of Ioannina, Ioannina, Greece
- Correspondence: Stelios Tigas Department of Endocrinology, University of Ioannina, Ioannina45110, GreeceTel +30 2651007800 Email
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409
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Henne M, Goodman JM, Hariri H. Spatial compartmentalization of lipid droplet biogenesis. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158499. [PMID: 31352131 PMCID: PMC7050823 DOI: 10.1016/j.bbalip.2019.07.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 07/08/2019] [Accepted: 07/09/2019] [Indexed: 12/18/2022]
Abstract
Lipid droplets (LDs) are ubiquitous organelles that store metabolic energy in the form of neutral lipids (typically triacylglycerols and steryl esters). Beyond being inert energy storage compartments, LDs are dynamic organelles that participate in numerous essential metabolic functions. Cells generate LDs de novo from distinct sub-regions at the endoplasmic reticulum (ER), but what determines sites of LD formation remains a key unanswered question. Here, we review the factors that determine LD formation at the ER, and discuss how they work together to spatially and temporally coordinate LD biogenesis. These factors include lipid synthesis enzymes, assembly proteins, and membrane structural requirements. LDs also make contact with other organelles, and these inter-organelle contacts contribute to defining sites of LD production. Finally, we highlight emerging non-canonical roles for LDs in maintaining cellular homeostasis during stress.
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Affiliation(s)
- Mike Henne
- Department of Cell Biology and Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - Joel M Goodman
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - Hanaa Hariri
- Department of Cell Biology and Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, United States of America.
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410
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Gao F, Wan J, Xu B, Wang X, Lin X, Wang P. Trajectories of Waist-to-Hip Ratio and Adverse Outcomes in Heart Failure with Mid-Range Ejection Fraction. Obes Facts 2020; 13:344-357. [PMID: 32570251 PMCID: PMC7445556 DOI: 10.1159/000507708] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 04/02/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Waist-to-hip ratio (WHR) is a strong predictor of mortality in patients with heart failure (HF). However, common WHR trajectories are not well established in HF with mid-range ejection fraction (HFmrEF) persons, and their relationship to clinical outcomes remains uncertain. METHOD We prospectively enrolled 1,396 participants with HFmrEF (left ventricular ejection fraction 40-49%) from April 2013 through April 2017. The waist and hip circumferences of the subjects were measured at regular intervals, and the WHR was calculated as waist circumference divided by hip circumference. Latent mixture modeling was performed to identify WHR trajectories. We then used Cox proportional-hazard models to examine the association between WHR trajectory patterns and incident HF, incident cardiovascular disease (CVD), and all-cause mortality. RESULTS We identified four distinct WHR trajectory patterns: lean-moderate increase (9.2%), medium-stable/increase (32.7%), heavy-stable/increase (48.0%), and heavy-moderate decrease (10.1%). After multivariable adjustment, the heavy-stable/increase and heavy-moderate decrease patterns were associated with an increased all-cause mortality risk (heavy-stable/increase: adjusted hazard ratio [HR] 3.18, 95% confidence interval [CI] 2.75-4.62; heavy-moderate decrease: adjusted HR 2.32, 95% CI 1.71-3.04), incident CVD risk (heavy-stable/increase: adjusted HR 4.03, 95% CI 2.39-4.91; heavy-moderate decrease: adjusted HR 3.05, 95% CI 2.34-4.09), and incident HF risk (heavy-stable/increase: adjusted HR 2.72, 95% CI 2.05-3.28; heavy-moderate decrease: adjusted HR 2.39, 95% CI 1.80-3.03) with reference to the lean-moderate increase pattern. CONCLUSION Among patients with HFmrEF, the trajectories of WHR gain are associated with poor outcomes. These findings highlight the importance of abdominal fat accumulation management during the progression of HFmrEF.
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Affiliation(s)
- Feng Gao
- Department of Cardiology, The Second Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Jindong Wan
- Department of Cardiology, The First Affiliated Hospital of Chengdu Medical College, Chengdu, China
- Key Laboratory of Aging and Vascular Homeostasis of Sichuan Higher Education Institutes, Chengdu, China
| | - Banglong Xu
- Department of Cardiology, The Second Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Xiaochen Wang
- Department of Cardiology, The Second Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Xianhe Lin
- Department of Cardiology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
- **Xianhe Lin, Department of Cardiology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230022 (PR China),
| | - Peijian Wang
- Department of Cardiology, The First Affiliated Hospital of Chengdu Medical College, Chengdu, China
- Key Laboratory of Aging and Vascular Homeostasis of Sichuan Higher Education Institutes, Chengdu, China
- *Peijian Wang, Department of Cardiology, The First Affiliated Hospital of, Chengdu Medical College, 278 Baoguang Avenue, Xindu District, Chengdu, Sichuan 610500 (PR China),
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411
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Tam V, Patel N, Turcotte M, Bossé Y, Paré G, Meyre D. Benefits and limitations of genome-wide association studies. Nat Rev Genet 2019; 20:467-484. [PMID: 31068683 DOI: 10.1038/s41576-019-0127-1] [Citation(s) in RCA: 933] [Impact Index Per Article: 186.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Genome-wide association studies (GWAS) involve testing genetic variants across the genomes of many individuals to identify genotype-phenotype associations. GWAS have revolutionized the field of complex disease genetics over the past decade, providing numerous compelling associations for human complex traits and diseases. Despite clear successes in identifying novel disease susceptibility genes and biological pathways and in translating these findings into clinical care, GWAS have not been without controversy. Prominent criticisms include concerns that GWAS will eventually implicate the entire genome in disease predisposition and that most association signals reflect variants and genes with no direct biological relevance to disease. In this Review, we comprehensively assess the benefits and limitations of GWAS in human populations and discuss the relevance of performing more GWAS.
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Affiliation(s)
- Vivian Tam
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Ontario, Canada
| | - Nikunj Patel
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Ontario, Canada
| | - Michelle Turcotte
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Ontario, Canada
| | - Yohan Bossé
- Institut Universitaire de Cardiologie et de Pneumologie de Québec-Université Laval, Québec City, Québec, Canada.,Department of Molecular Medicine, Laval University, Québec City, Quebec, Canada
| | - Guillaume Paré
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Ontario, Canada.,Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - David Meyre
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Ontario, Canada. .,Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada. .,Inserm UMRS 954 N-GERE (Nutrition-Genetics-Environmental Risks), University of Lorraine, Faculty of Medicine, Nancy, France.
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412
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Pan X, Kaminga AC, Wen SW, Acheampong K, Liu A. Omentin-1 in diabetes mellitus: A systematic review and meta-analysis. PLoS One 2019; 14:e0226292. [PMID: 31821362 PMCID: PMC6903756 DOI: 10.1371/journal.pone.0226292] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 11/22/2019] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVE Previous studies found inconsistent results on the relationship between diabetes mellitus and concentrations of omentin-1. This study performed a systematic review and meta-analysis to summarize previous findings on this relationship. METHODS Studies related to this outcome were obtained using a systematic search in the electronic databases of Cochrane Library, PubMed, Embase, SCOPUS, Google Scholar, gray literature and Web of Science in September 2019. The random effects model was used to measure the strength of the association between diabetes mellitus and concentrations of omentin-1, using standardized mean difference. RESULTS Forty-two eligible studies were included in the final meta-analysis. There was no significant difference in omentin-1 concentration between patients with type 1 diabetes mellitus and the controls. On the other hand, lower concentration levels of omentin-1 were observed in patients with gestational diabetes mellitus (standardized mean difference:-0.44, 95% confidence interval:-0.76; -0.12, p = 0.007), or type 2 diabetes mellitus (standardized mean difference: -1.74, 95% confidence interval: -2.31; -1.16, p< 0.001) than in the controls. CONCLUSION Decreased omentin-1 concentrations may be an important indicator for gestational diabetes mellitus and type 2 diabetes mellitus. More studies are needed to validate this hypothesis and evaluate the role of omentin-1 concentrations in type 1 diabetes mellitus.
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Affiliation(s)
- Xiongfeng Pan
- Department of Epidemiology and Health Statistics, Xiangya School of Public Health, Central South University, Changsha, China
| | - Atipatsa C. Kaminga
- Department of Epidemiology and Health Statistics, Xiangya School of Public Health, Central South University, Changsha, China
- Department of Mathematics and Statistics, Mzuzu University, Mzuzu, Malawi
| | - Shi Wu Wen
- Department of Epidemiology and Health Statistics, Xiangya School of Public Health, Central South University, Changsha, China
- Department of Obstetrics and Gynaecology and Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Kwabena Acheampong
- Department of Epidemiology and Health Statistics, Xiangya School of Public Health, Central South University, Changsha, China
- Department of Public, School of Postgraduate Studies, Adventist University of Africa, Nairobi, Kenya
| | - Aizhong Liu
- Department of Epidemiology and Health Statistics, Xiangya School of Public Health, Central South University, Changsha, China
- * E-mail:
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413
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Yao Y, Li X, Wang W, Liu Z, Chen J, Ding M, Huang X. MRT, Functioning with NURF Complex, Regulates Lipid Droplet Size. Cell Rep 2019; 24:2972-2984. [PMID: 30208321 DOI: 10.1016/j.celrep.2018.08.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 06/08/2018] [Accepted: 08/09/2018] [Indexed: 12/27/2022] Open
Abstract
Lipid droplets (LDs) are highly dynamic organelles that store neutral lipids. Through a gene overexpression screen in the Drosophila larval fat body, we have identified that MRT, an Myb/switching-defective protein 3 (Swi3), Adaptor 2 (Ada2), Nuclear receptor co-repressor (N-CoR), Transcription factor (TF)IIIB (SANT)-like DNA-binding domain-containing protein, regulates LD size and lipid storage. MRT directly interacts with, and is functionally dependent on, the PZG and NURF chromatin-remodeling complex components. MRT binds to the promoter of plin1, the gene encoding the LD-resident protein perilipin, and inhibits the transcription of plin1. In vitro LD coalescence assays suggest that mrt overexpression or loss of plin1 function facilitates LD coalescence. Our findings suggest that MRT functions together with chromatin-remodeling factors to regulate LD size, likely through the transcriptional repression of plin1.
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Affiliation(s)
- Yan Yao
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xia Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Wei Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhonghua Liu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jianming Chen
- Sino-French Hoffmann Institute, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou 511436, China
| | - Mei Ding
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xun Huang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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414
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Hodson L, Gunn PJ. The regulation of hepatic fatty acid synthesis and partitioning: the effect of nutritional state. Nat Rev Endocrinol 2019; 15:689-700. [PMID: 31554932 DOI: 10.1038/s41574-019-0256-9] [Citation(s) in RCA: 133] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is an increasing global public health burden. NAFLD is strongly associated with type 2 diabetes mellitus, obesity and cardiovascular disease and begins with intrahepatic triacylglycerol accumulation. Under healthy conditions, the liver regulates lipid metabolism to meet systemic energy needs in the fed and fasted states. The processes of fatty acid uptake, fatty acid synthesis and the intracellular partitioning of fatty acids into storage, oxidation and secretion pathways are tightly regulated. When one or more of these processes becomes dysregulated, excess lipid accumulation can occur. Although genetic and environmental factors have been implicated in the development of NAFLD, it remains unclear why an imbalance in these pathways begins. The regulation of fatty acid partitioning occurs at several points, including during triacylglycerol synthesis, lipid droplet formation and lipolysis. These processes are influenced by enzyme function, intake of dietary fats and sugars and whole-body metabolism, and are further affected by the presence of obesity or insulin resistance. Insight into how the liver controls fatty acid metabolism in health and how these processes might be affected in disease would offer the potential for new therapeutic treatments for NAFLD to be developed.
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Affiliation(s)
- Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Headington, Oxford, UK.
- Oxford NIHR Biomedical Research Centre, Churchill Hospital, Headington, Oxford, UK.
| | - Pippa J Gunn
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Headington, Oxford, UK
- Oxford NIHR Biomedical Research Centre, Churchill Hospital, Headington, Oxford, UK
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415
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Madadi S, Schwarzenbach H, Saidijam M, Mahjub R, Soleimani M. Potential microRNA-related targets in clearance pathways of amyloid-β: novel therapeutic approach for the treatment of Alzheimer's disease. Cell Biosci 2019; 9:91. [PMID: 31749959 PMCID: PMC6852943 DOI: 10.1186/s13578-019-0354-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 11/01/2019] [Indexed: 02/07/2023] Open
Abstract
Imbalance between amyloid-beta (Aβ) peptide synthesis and clearance results in Aβ deregulation. Failure to clear these peptides appears to cause the development of Alzheimer's disease (AD). In recent years, microRNAs have become established key regulators of biological processes that relate among others to the development and progression of neurodegenerative diseases, such as AD. This review article gives an overview on microRNAs that are involved in the Aβ cascade and discusses their inhibitory impact on their target mRNAs whose products participate in Aβ clearance. Understanding of the mechanism of microRNA in the associated signal pathways could identify novel therapeutic targets for the treatment of AD.
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Affiliation(s)
- Soheil Madadi
- Department of Pharmaceutical Biotechnology, School of Pharmacy, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Heidi Schwarzenbach
- Department of Tumor Biology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Massoud Saidijam
- Department of Genetics and Molecular Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Reza Mahjub
- Department of Pharmaceutics, School of Pharmacy, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Meysam Soleimani
- Department of Pharmaceutical Biotechnology, School of Pharmacy, Hamadan University of Medical Sciences, Hamadan, Iran
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416
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Beijer K, Nowak C, Sundström J, Ärnlöv J, Fall T, Lind L. In search of causal pathways in diabetes: a study using proteomics and genotyping data from a cross-sectional study. Diabetologia 2019; 62:1998-2006. [PMID: 31446444 PMCID: PMC6805963 DOI: 10.1007/s00125-019-4960-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 06/06/2019] [Indexed: 12/12/2022]
Abstract
AIMS/HYPOTHESIS The pathogenesis of type 2 diabetes is not fully understood. We investigated whether circulating levels of preselected proteins were associated with the outcome 'diabetes' and whether these associations were causal. METHODS In 2467 individuals of the population-based, cross-sectional EpiHealth study (45-75 years, 50% women), 249 plasma proteins were analysed by the proximity extension assay technique. DNA was genotyped using the Illumina HumanCoreExome-12 v1.0 BeadChip. Diabetes was defined as taking glucose-lowering treatment or having a fasting plasma glucose of ≥7.0 mmol/l. The associations between proteins and diabetes were assessed using logistic regression. To investigate causal relationships between proteins and diabetes, a bidirectional two-sample Mendelian randomisation was performed based on large, genome-wide association studies belonging to the DIAGRAM and MAGIC consortia, and a genome-wide association study in the EpiHealth study. RESULTS Twenty-six proteins were positively associated with diabetes, including cathepsin D, retinal dehydrogenase 1, α-L-iduronidase, hydroxyacid oxidase 1 and galectin-4 (top five findings). Three proteins, lipoprotein lipase, IGF-binding protein 2 and paraoxonase 3 (PON-3), were inversely associated with diabetes. Fourteen of the proteins are novel discoveries. The Mendelian randomisation study did not disclose any significant causal effects between the proteins and diabetes in either direction that were consistent with the relationships found between the protein levels and diabetes. CONCLUSIONS/INTERPRETATION The 29 proteins associated with diabetes are involved in several physiological pathways, but given the power of the study no causal link was identified for those proteins tested in Mendelian randomisation. Therefore, the identified proteins are likely to be biomarkers for type 2 diabetes, rather than representing causal pathways.
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Affiliation(s)
- Kristina Beijer
- Department of Medical Sciences, Uppsala University, UCR, Dag Hammarskjölds väg 38, SE-751 83, Uppsala, Sweden.
| | - Christoph Nowak
- Department of Neurobiology, Care Sciences and Society, Division of Family Medicine and Primary Care, Karolinska Institute, Stockholm, Sweden
| | - Johan Sundström
- Department of Medical Sciences, Uppsala University, UCR, Dag Hammarskjölds väg 38, SE-751 83, Uppsala, Sweden
| | - Johan Ärnlöv
- Department of Neurobiology, Care Sciences and Society, Division of Family Medicine and Primary Care, Karolinska Institute, Stockholm, Sweden
- School of Health and Social Sciences, Dalarna University, Falun, Sweden
| | - Tove Fall
- Department of Medical Sciences, Uppsala University, UCR, Dag Hammarskjölds väg 38, SE-751 83, Uppsala, Sweden
| | - Lars Lind
- Department of Medical Sciences, Uppsala University, UCR, Dag Hammarskjölds väg 38, SE-751 83, Uppsala, Sweden
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417
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Neufeldt CJ, Cortese M, Scaturro P, Cerikan B, Wideman JG, Tabata K, Moraes T, Oleksiuk O, Pichlmair A, Bartenschlager R. ER-shaping atlastin proteins act as central hubs to promote flavivirus replication and virion assembly. Nat Microbiol 2019; 4:2416-2429. [PMID: 31636417 PMCID: PMC6881184 DOI: 10.1038/s41564-019-0586-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Accepted: 09/10/2019] [Indexed: 12/13/2022]
Abstract
Flaviviruses, including dengue virus (DV) and Zika virus, extensively remodel the cellular endomembrane network to generate replication organelles that promote viral genome replication and virus production. However, it remains unclear how these membranes and associated cellular proteins act during the virus cycle. Here, we show that atlastins (ATLs), a subset of ER resident proteins involved in neurodegenerative diseases, have dichotomous effects on flaviviruses with ATL2 depletion leading to replication organelle defects and ATL3 depletion to changes in virus production pathways. We characterized non-conserved functional domains in ATL paralogues and show that the ATL interactome is profoundly reprogrammed upon DV infection. Screen analysis confirmed non-redundant ATL functions and identified a specific role for ATL3, and its interactor ARF4, in vesicle trafficking and virion maturation. Our data identify ATLs as central hubs targeted by flaviviruses to establish their replication organelle and to achieve efficient virion maturation and secretion.
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Affiliation(s)
- Christopher J Neufeldt
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Heidelberg, Germany.
| | - Mirko Cortese
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Heidelberg, Germany
| | - Pietro Scaturro
- Technical University of Munich, School of Medicine, Institute of Virology, Munich, Germany
| | - Berati Cerikan
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Heidelberg, Germany
| | - Jeremy G Wideman
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada.,Biodesign Center for Mechanisms of Evolution, School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Keisuke Tabata
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Heidelberg, Germany
| | - Thaís Moraes
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Heidelberg, Germany
| | - Olga Oleksiuk
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Heidelberg, Germany
| | - Andreas Pichlmair
- Technical University of Munich, School of Medicine, Institute of Virology, Munich, Germany.,German Center for Infection Research (DZIF), (Munich Partner Site), Munich, Germany
| | - Ralf Bartenschlager
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Heidelberg, Germany. .,German Center for Infection Research (DZIF), (Heidelberg Partner Site), Heidelberg, Germany. .,Division Virus-Associated Carcinogenesis, German Cancer Research Center, Heidelberg, Germany.
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418
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Fowler PC, Garcia-Pardo ME, Simpson JC, O'Sullivan NC. NeurodegenERation: The Central Role for ER Contacts in Neuronal Function and Axonopathy, Lessons From Hereditary Spastic Paraplegias and Related Diseases. Front Neurosci 2019; 13:1051. [PMID: 31680803 PMCID: PMC6801308 DOI: 10.3389/fnins.2019.01051] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 09/19/2019] [Indexed: 12/17/2022] Open
Abstract
The hereditary spastic paraplegias (HSPs) are a group of inherited neurodegenerative conditions whose characteristic feature is degeneration of the longest axons within the corticospinal tract which leads to progressive spasticity and weakness of the lower limbs. Though highly genetically heterogeneous, the majority of HSP cases are caused by mutations in genes encoding proteins that are responsible for generating and organizing the tubular endoplasmic reticulum (ER). Despite this, the role of the ER within neurons, particularly the long axons affected in HSP, is not well understood. Throughout axons, ER tubules make extensive contacts with other organelles, the cytoskeleton and the plasma membrane. At these ER contacts, protein complexes work in concert to perform specialized functions including organelle shaping, calcium homeostasis and lipid biogenesis, all of which are vital for neuronal survival and may be disrupted by HSP-causing mutations. In this article we summarize the proteins which mediate ER contacts, review the functions these contacts are known to carry out within neurons, and discuss the potential contribution of disruption of ER contacts to axonopathy in HSP.
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Affiliation(s)
- Philippa C Fowler
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - M Elena Garcia-Pardo
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Jeremy C Simpson
- UCD School of Biology and Environmental Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Niamh C O'Sullivan
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
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419
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Zheng Q, Jiang J, Huo Y, Chen D. Genetic predisposition to type 2 diabetes is associated with severity of coronary artery disease in patients with acute coronary syndromes. Cardiovasc Diabetol 2019; 18:131. [PMID: 31594547 PMCID: PMC6784340 DOI: 10.1186/s12933-019-0930-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Accepted: 09/17/2019] [Indexed: 12/24/2022] Open
Abstract
Background Accumulating evidence has shown that type 2 diabetes (T2D) and coronary artery disease (CAD) may stem from a ‘common soil’. The aim of our study was to examine the association between genetic predisposition to T2D and the risk of severe CAD among patients with acute coronary syndromes (ACS) undergoing angiography. Methods The current case–control study included 1414 ACS patients with at least one major epicardial vessel stenosis > 50% enrolled in the ACS Genetic Study. The severity of CAD was quantified by the number of coronary arteries involved. Genetic risk score (GRS) was calculated using 41 common variants that robustly associated with increased risk of T2D in East Asians. Logistic regression models were used to estimate the association between GRS and the severity of CAD. Results In the age-, sex- and BMI-adjusted model, each additional risk allele was associated with a 6% increased risk of multi-vessel disease (OR = 1.06, 95% CI 1.02–1.09). The OR was 1.43 (95% CI 1.08–1.89) for the risk of severe CAD when comparing the extreme tertiles of T2D-GRS. The association was not reduced after further adjustment for conventional cardiovascular risk factors. Additional adjustment for T2D status in our regression model attenuated the association by approximately one quarter. In subgroup analysis, the strengths of the associations between GRS and the severity of CAD were broadly similar in terms of baseline demographic information and disease characteristics. Conclusions Our data indicated that genetic predisposition to T2D is associated with elevated risk of severe CAD. This association revealed a possible causal relationship and is partially mediated through diabetic status.
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Affiliation(s)
- Qiwen Zheng
- Department of Epidemiology and Biostatistics, School of Public Health, Peking University, No. 38 Xueyuan Road, Haidian District, Beijing, 100191, China
| | - Jie Jiang
- Department of Cardiology, Peking University First Hospital, No. 8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Yong Huo
- Department of Cardiology, Peking University First Hospital, No. 8 Xishiku Street, Xicheng District, Beijing, 100034, China.
| | - Dafang Chen
- Department of Epidemiology and Biostatistics, School of Public Health, Peking University, No. 38 Xueyuan Road, Haidian District, Beijing, 100191, China.
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420
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Censin JC, Peters SAE, Bovijn J, Ferreira T, Pulit SL, Mägi R, Mahajan A, Holmes MV, Lindgren CM. Causal relationships between obesity and the leading causes of death in women and men. PLoS Genet 2019; 15:e1008405. [PMID: 31647808 PMCID: PMC6812754 DOI: 10.1371/journal.pgen.1008405] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 09/09/2019] [Indexed: 12/25/2022] Open
Abstract
Obesity traits are causally implicated with risk of cardiometabolic diseases. It remains unclear whether there are similar causal effects of obesity traits on other non-communicable diseases. Also, it is largely unexplored whether there are any sex-specific differences in the causal effects of obesity traits on cardiometabolic diseases and other leading causes of death. We constructed sex-specific genetic risk scores (GRS) for three obesity traits; body mass index (BMI), waist-hip ratio (WHR), and WHR adjusted for BMI, including 565, 324, and 337 genetic variants, respectively. These GRSs were then used as instrumental variables to assess associations between the obesity traits and leading causes of mortality in the UK Biobank using Mendelian randomization. We also investigated associations with potential mediators, including smoking, glycemic and blood pressure traits. Sex-differences were subsequently assessed by Cochran's Q-test (Phet). A Mendelian randomization analysis of 228,466 women and 195,041 men showed that obesity causes coronary artery disease, stroke (particularly ischemic), chronic obstructive pulmonary disease, lung cancer, type 2 and 1 diabetes mellitus, non-alcoholic fatty liver disease, chronic liver disease, and acute and chronic renal failure. Higher BMI led to higher risk of type 2 diabetes in women than in men (Phet = 1.4×10-5). Waist-hip-ratio led to a higher risk of chronic obstructive pulmonary disease (Phet = 3.7×10-6) and higher risk of chronic renal failure (Phet = 1.0×10-4) in men than women. Obesity traits have an etiological role in the majority of the leading global causes of death. Sex differences exist in the effects of obesity traits on risk of type 2 diabetes, chronic obstructive pulmonary disease, and renal failure, which may have downstream implications for public health.
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Affiliation(s)
- Jenny C. Censin
- Big Data Institute at the Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
- Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Sanne A. E. Peters
- The George Institute for Global Health, University of Oxford, Oxford, United Kingdom
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jonas Bovijn
- Big Data Institute at the Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
- Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Teresa Ferreira
- Big Data Institute at the Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
| | - Sara L. Pulit
- Big Data Institute at the Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
- Department of Genetics, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht, The Netherlands
- Program in Medical and Population Genetics, Broad Institute, Cambridge, Massachusetts, United States of America
| | - Reedik Mägi
- Estonian Genome Center, Institute of Genomics, University of Tartu, Tartu, Estonia
| | - Anubha Mahajan
- Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Michael V. Holmes
- NIHR Oxford Biomedical Research Centre, Oxford University Hospitals NHS Foundation Trust, John Radcliffe Hospital, Oxford, United Kingdom
- Medical Research Council Population Health Research Unit at the University of Oxford, Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom
- Clinical Trial Service Unit & Epidemiological Studies Unit (CTSU), Nuffield Department of Population Health, Big Data Institute Building, Roosevelt Drive, University of Oxford, Oxford, United Kingdom
| | - Cecilia M. Lindgren
- Big Data Institute at the Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
- Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Program in Medical and Population Genetics, Broad Institute, Cambridge, Massachusetts, United States of America
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Xiang R, Fan LL, Huang H, Chen YQ, He W, Guo S, Li JJ, Jin JY, Du R, Yan R, Xia K. Increased Reticulon 3 (RTN3) Leads to Obesity and Hypertriglyceridemia by Interacting With Heat Shock Protein Family A (Hsp70) Member 5 (HSPA5). Circulation 2019; 138:1828-1838. [PMID: 29716941 DOI: 10.1161/circulationaha.117.030718] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Reticulon 3 (RTN3) is an endoplasmic reticulum protein that has previously been shown to play a role in neurodegenerative diseases, but little is known about its role in lipid metabolism. METHODS Obese patients (n=149), hypertriglyceridemic patients (n=343), and healthy control subjects (n=84) were enrolled to assess their levels of RTN3. To explore the pathophysiological roles of RTN3 in the control of lipid metabolism, we used transgenic mice overexpressing the wild-type human RTN3 gene, the RTN3-null transgenic mouse model, and multiple Caenorhabditis legans strains for molecular characterization. The underlying mechanisms were studied with 3T3L1 cell cultures in vitro. RESULTS We report that overexpressed RTN3 in mice induces obesity and higher accumulation of triglycerides. Increased RTN3 expression is also found in patients with obesity and hypertriglyceridemia. We reveal that RTN3 plays critical roles in regulating the biosynthesis and storage of triglycerides and in controlling lipid droplet expansion. Mechanistically, RTN3 regulates these events through its interactions with heat shock protein family A (Hsp70) member 5, and this enhanced interaction increases sterol regulatory element-binding protein 1c and AMP-activated kinase activity. CONCLUSIONS This study provides evidence for a role of RTN3 in inducing obesity and triglyceride accumulation and suggests that inhibiting the expression of RTN3 in fat tissue may be a novel therapeutic approach to treat obesity and hypertriglyceridemia.
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Affiliation(s)
- Rong Xiang
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, China (R.X., L.-l.F., H.H., S.G., J.-J.L., J.-y.J., R.D., K.X.)
| | - Liang-Liang Fan
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, China (R.X., L.-l.F., H.H., S.G., J.-J.L., J.-y.J., R.D., K.X.)
| | - Hao Huang
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, China (R.X., L.-l.F., H.H., S.G., J.-J.L., J.-y.J., R.D., K.X.)
| | - Ya-Qin Chen
- Department of Cardiology, Second Xiangya Hospital of Central South University, Changsha, China (Y.-q.C.)
| | - Wanxia He
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, OH (W.H., R.Y.)
| | - Shuai Guo
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, China (R.X., L.-l.F., H.H., S.G., J.-J.L., J.-y.J., R.D., K.X.)
| | - Jing-Jing Li
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, China (R.X., L.-l.F., H.H., S.G., J.-J.L., J.-y.J., R.D., K.X.)
| | - Jie-Yuan Jin
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, China (R.X., L.-l.F., H.H., S.G., J.-J.L., J.-y.J., R.D., K.X.)
| | - Ran Du
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, China (R.X., L.-l.F., H.H., S.G., J.-J.L., J.-y.J., R.D., K.X.)
| | - Riqiang Yan
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, OH (W.H., R.Y.)
| | - Kun Xia
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, China (R.X., L.-l.F., H.H., S.G., J.-J.L., J.-y.J., R.D., K.X.)
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O'Mara TA, Spurdle AB, Glubb DM. Analysis of Promoter-Associated Chromatin Interactions Reveals Biologically Relevant Candidate Target Genes at Endometrial Cancer Risk Loci. Cancers (Basel) 2019; 11:cancers11101440. [PMID: 31561579 PMCID: PMC6826789 DOI: 10.3390/cancers11101440] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 09/19/2019] [Accepted: 09/23/2019] [Indexed: 02/06/2023] Open
Abstract
The identification of target genes at genome-wide association study (GWAS) loci is a major obstacle for GWAS follow-up. To identify candidate target genes at the 16 known endometrial cancer GWAS risk loci, we performed HiChIP chromatin looping analysis of endometrial cell lines. To enrich for enhancer-promoter interactions, a mechanism through which GWAS variation may target genes, we captured chromatin loops associated with H3K27Ac histone, characteristic of promoters and enhancers. Analysis of HiChIP loops contacting promoters revealed enrichment for endometrial cancer GWAS heritability and intersection with endometrial cancer risk variation identified 103 HiChIP target genes at 13 risk loci. Expression of four HiChIP target genes (SNX11, SRP14, HOXB2 and BCL11A) was associated with risk variation, providing further evidence for their targeting. Network analysis functionally prioritized a set of proteins that interact with those encoded by HiChIP target genes, and this set was enriched for pan-cancer and endometrial cancer drivers. Lastly, HiChIP target genes and prioritized interacting proteins were over-represented in pathways related to endometrial cancer development. In summary, we have generated the first global chromatin looping data from normal and tumoral endometrial cells, enabling analysis of all known endometrial cancer risk loci and identifying biologically relevant candidate target genes.
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Affiliation(s)
- Tracy A O'Mara
- Department of Genetics and Computational Biology, QIMR Berghofer Medical Research Institute, Brisbane QLD 4006, Australia.
| | - Amanda B Spurdle
- Department of Genetics and Computational Biology, QIMR Berghofer Medical Research Institute, Brisbane QLD 4006, Australia.
| | - Dylan M Glubb
- Department of Genetics and Computational Biology, QIMR Berghofer Medical Research Institute, Brisbane QLD 4006, Australia.
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423
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Agbim U, Carr RM, Pickett-Blakely O, Dagogo-Jack S. Ethnic Disparities in Adiposity: Focus on Non-alcoholic Fatty Liver Disease, Visceral, and Generalized Obesity. Curr Obes Rep 2019; 8:243-254. [PMID: 31144261 PMCID: PMC6662200 DOI: 10.1007/s13679-019-00349-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE OF REVIEW Excessive adiposity has become a public health problem worldwide, contributing to the rise in obesity-related diseases and associated morbidity and mortality. This review details the relative significance of race/ethnicity as it pertains to adiposity and non-alcoholic fatty liver disease (NAFLD). RECENT FINDINGS Fat distribution remains a more reliable measure of adiposity than anthropometric measures, with visceral adipose tissue (VAT) associated with increased risk of cardiometabolic disease. While obesity is the most common risk factor for NAFLD, the racial/ethnic prevalence of obesity does not completely parallel NAFLD risk. Combating racial/ethnic disparities in obesity requires understanding differential risk among various groups. Hispanics are disproportionally impacted by NAFLD and have high rates of obesity, VAT, and insulin resistance (IR). This contrasts with Blacks, who have high prevalence of obesity and IR, accompanied by a paradoxically favorable lipid profile and low prevalence of VAT and NAFLD. Many features of adiposity and NAFLD are mediated by genetic and environmental factors, the latter being modifiable and the focus of interventions.
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Affiliation(s)
- Uchenna Agbim
- Division of Transplant Surgery, Department of Surgery, Methodist University Hospital Transplant Institute, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Rotonya M Carr
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Octavia Pickett-Blakely
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Sam Dagogo-Jack
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, University of Tennessee Health Science Center, 920 Madison Avenue, Suite 300A, Memphis, TN, 38163, USA.
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424
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Lee JW, Kim SY, Lee HJ, Han SW, Lee JE, Lee SM. Prognostic Significance of Abdominal-to-Gluteofemoral Adipose Tissue Distribution in Patients with Breast Cancer. J Clin Med 2019; 8:jcm8091358. [PMID: 31480613 PMCID: PMC6781262 DOI: 10.3390/jcm8091358] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 08/22/2019] [Indexed: 12/24/2022] Open
Abstract
This study aimed to evaluate the association between abdominal-to-gluteofemoral adipose tissue (AT) distribution and recurrence-free survival (RFS) in breast cancer patients. Staging F-18 fluorodexoyglucose (FDG) positron emission tomography/computed tomography (PET/CT) images of 336 women with breast cancer were retrospectively analyzed. From CT images, the volume and CT-attenuation of visceral adipose tissue (VAT), abdominal subcutaneous adipose tissue (SAT), and gluteofemoral AT were measured and the ratio of abdomen-to-gluteofemoral AT volume (AG volume ratio) was calculated. The relationships between adipose tissue parameters and RFS were assessed. Through univariate analysis, abdominal SAT volume, gluteofemoral AT volume, and AG volume ratio were significantly associated with RFS. An increase in abdominal SAT volume and AG volume ratio were associated with an increased risk of recurrence, whereas increased gluteofemoral AT volume was associated with a decreased risk of recurrence. On multivariate analysis, abdominal SAT volume, gluteofemoral AT volume, and AG volume ratio were found to be significant predictors of RFS after adjusting for clinic-histological factors. Irrespective of obesity, patients with a high AG volume ratio showed a higher recurrence rate than those with a low AG volume ratio. Increased abdominal SAT volume and decreased gluteofemoral AT volume were related to poor RFS in breast cancer patients.
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Affiliation(s)
- Jeong Won Lee
- Department of Nuclear Medicine, International St. Mary's Hospital, Catholic Kwandong University College of Medicine, 25 Simgok-ro 100 beon-gil, Seo-gu, Incheon 22711, Korea
| | - Sung Yong Kim
- Department of Surgery, Soonchunhyang University Cheonan Hospital, 31 Suncheonhyang 6-gil, Dongnam-gu, Cheonan, Chungcheongnam-do 31151, Korea
| | - Hyun Ju Lee
- Department of Pathology, Soonchunhyang University Cheonan Hospital, 31 Suncheonhyang 6-gil, Dongnam-gu, Cheonan, Chungcheongnam-do 31151, Korea
| | - Sun Wook Han
- Department of Surgery, Soonchunhyang University Cheonan Hospital, 31 Suncheonhyang 6-gil, Dongnam-gu, Cheonan, Chungcheongnam-do 31151, Korea
| | - Jong Eun Lee
- Department of Surgery, Soonchunhyang University Cheonan Hospital, 31 Suncheonhyang 6-gil, Dongnam-gu, Cheonan, Chungcheongnam-do 31151, Korea
| | - Sang Mi Lee
- Department of Nuclear Medicine, Soonchunhyang University Cheonan Hospital, 31 Suncheonhyang 6-gil, Dongnam-gu, Cheonan, Chungcheongnam-do 31151, Korea.
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425
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Macchi C, Sirtori CR, Corsini A, Santos RD, Watts GF, Ruscica M. A new dawn for managing dyslipidemias: The era of rna-based therapies. Pharmacol Res 2019; 150:104413. [PMID: 31449975 DOI: 10.1016/j.phrs.2019.104413] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Revised: 08/08/2019] [Accepted: 08/22/2019] [Indexed: 12/24/2022]
Abstract
The high occurrence of atherosclerotic cardiovascular disease (ASCVD) events is still a major public health issue. Although a major determinant of ASCVD event reduction is the absolute change of low-density lipoprotein-cholesterol (LDL-C), considerable residual risk remains and new therapeutic options are required, in particular, to address triglyceride-rich lipoproteins and lipoprotein(a) [Lp(a)]. In the era of Genome Wide Association Studies and Mendelian Randomization analyses aimed at increasing the understanding of the pathophysiology of ASCVD, RNA-based therapies may offer more effective treatment options. The advantage of oligonucleotide-based treatments is that drug candidates are targeted at highly specific regions of RNA that code for proteins that in turn regulate lipid and lipoprotein metabolism. For LDL-C lowering, the use of inclisiran - a silencing RNA that inhibits proprotein convertase subtilisin/kexin type 9 (PCSK9) synthesis - has the advantage that a single s.c. injection lowers LDL-C for up to 6 months. In familial hypercholesterolemia, the use of the antisense oligonucleotide (ASO) mipomersen, targeting apolipoprotein (apoB) to reduce LDL-C, has been a valuable therapeutic approach, despite unquestionable safety concerns. The availability of specific ASOs lowering Lp(a) levels will allow rigorous testing of the Lp(a) hypothesis; by dramatically reducing plasma triglyceride levels, Volanesorsen (APOC3) and angiopoietin-like 3 (ANGPTL3)-LRx will further clarify the causality of triglyceride-rich lipoproteins in ASCVD. The rapid progress to date heralds a new dawn in therapeutic lipidology, but outcome, safety and cost-effectiveness studies are required to establish the role of these new agents in clinical practice.
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Affiliation(s)
- C Macchi
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - C R Sirtori
- Dyslipidemia Center, A.S.S.T. Grande Ospedale Metropolitano Niguarda, Milan, Italy
| | - A Corsini
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy; IRCCS Multimedica, Milan, Italy
| | - R D Santos
- Lipid Clinic, Heart Institute (InCor), University of Sao Paulo, Brazil; Hospital Israelita Albert Einstein, São Paulo, Brazil
| | - G F Watts
- School of Medicine, Faculty of Health and Medical Sciences, University of Western Australia, Perth, Australia; Lipid Disorders Clinic, Cardiometabolic Services, Department of Cardiology, Royal Perth Hospital, Australia.
| | - M Ruscica
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
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426
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Abstract
Lipodystrophies are the result of a range of inherited and acquired causes, but all are characterized by perturbations in white adipose tissue function and, in many instances, its mass or distribution. Though patients are often nonobese, they typically manifest a severe form of the metabolic syndrome, highlighting the importance of white fat in the "safe" storage of surplus energy. Understanding the molecular pathophysiology of congenital lipodystrophies has yielded useful insights into the biology of adipocytes and informed therapeutic strategies. More recently, genome-wide association studies focused on insulin resistance have linked common variants to genes implicated in adipose biology and suggested that subtle forms of lipodystrophy contribute to cardiometabolic disease risk at a population level. These observations underpin the use of aligned treatment strategies in insulin-resistant obese and lipodystrophic patients, the major goal being to alleviate the energetic burden on adipose tissue.
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427
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Abstract
PURPOSE OF REVIEW Lipodystrophy syndromes have an estimated prevalence of 1.3-4.7 cases per million and as with other rare diseases conducting research can be challenging. The present review highlights recently published work that has provided insights into the field of non-HIV--associated lipodystrophy syndromes. RECENT FINDINGS Lipodystrophies are a heterogenous group of disorders, as such research is often focused on specific subtypes of the condition. The identification of children carrying LMNA mutations has provided insights into the natural history of FPLD2, specifically that the adipose tissue phenotype predates the onset of puberty. Recent reports of PLIN1 heterozygous null variant carriers and the apparent absence of a lipodystrophy phenotype challenges our understanding of the molecular biology of perilipin 1 and its role in the pathogenesis of FPLD4. With a focus on therapeutics, studies delineating the differential responsiveness of PPARγ mutants to endogenous and synthetic ligands has illustrated the potential for pharmacogenetics to inform therapeutic decisions in lipodystrophy related to PPARG mutations, whereas robust human studies have provided insight into the food independent metabolic effects of leptin in lipodystrophy. Finally, rare syndromes of lipodystrophy continue to serve as an exemplar for the contribution of genetically determined adipose tissue expandability to metabolic disease in the general population. SUMMARY Lipodystrophy research continues to illuminate our understanding of this rare disease and the possibility that lipodystrophy syndromes and the metabolic syndrome may have shared pathophysiology.
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Affiliation(s)
- Audrey Melvin
- Metabolic Research Laboratories, Wellcome Trust - MRC Institute of Metabolic Science, University of Cambridge
- National Severe Insulin Resistance Service, Wolfson Diabetes & Endocrine Clinic, Cambridge University Hospitals NHS Foundation Trust, United Kingdom
| | - Anna Stears
- National Severe Insulin Resistance Service, Wolfson Diabetes & Endocrine Clinic, Cambridge University Hospitals NHS Foundation Trust, United Kingdom
| | - David B Savage
- Metabolic Research Laboratories, Wellcome Trust - MRC Institute of Metabolic Science, University of Cambridge
- National Severe Insulin Resistance Service, Wolfson Diabetes & Endocrine Clinic, Cambridge University Hospitals NHS Foundation Trust, United Kingdom
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428
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Ginsberg HN. Selective Trafficking of Fatty Acids in the Liver: Add Them2 to the List of Influencers. Hepatology 2019; 70:462-464. [PMID: 31155742 DOI: 10.1002/hep.30800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 05/29/2019] [Indexed: 12/07/2022]
Affiliation(s)
- Henry N Ginsberg
- Vagelos College of Physicians and Surgeons of Columbia University, New York, NY
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429
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Hereditary spastic paraplegia: from diagnosis to emerging therapeutic approaches. Lancet Neurol 2019; 18:1136-1146. [PMID: 31377012 DOI: 10.1016/s1474-4422(19)30235-2] [Citation(s) in RCA: 156] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 05/20/2019] [Accepted: 05/29/2019] [Indexed: 12/16/2022]
Abstract
Hereditary spastic paraplegia (HSP) describes a heterogeneous group of genetic neurodegenerative diseases characterised by progressive spasticity of the lower limbs. The pathogenic mechanism, associated clinical features, and imaging abnormalities vary substantially according to the affected gene and differentiating HSP from other genetic diseases associated with spasticity can be challenging. Next generation sequencing-based gene panels are now widely available but have limitations and a molecular diagnosis is not made in most suspected cases. Symptomatic management continues to evolve but with a greater understanding of the pathophysiological basis of individual HSP subtypes there are emerging opportunities to provide targeted molecular therapies and personalised medicine.
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430
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The biogenesis of lipid droplets: Lipids take center stage. Prog Lipid Res 2019; 75:100989. [PMID: 31351098 DOI: 10.1016/j.plipres.2019.100989] [Citation(s) in RCA: 95] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 05/21/2019] [Accepted: 06/27/2019] [Indexed: 11/20/2022]
Abstract
Lipid droplets (LDs) are multi-functional cellular organelles that store energy, and regulate many aspects of cell physiology. However, our understanding of the biogenesis of LDs remains very limited. Originating from the endoplasmic reticulum (ER), LDs are highly unique organelles in that each LD is bounded by a monolayer of amphipathic lipids. Recent progress has unveiled critical roles of non-bilayer lipids in LD formation. For instance, non-bilayer lipids such as lysophospholipids, diacylglycerol and phosphatidic acid (PA) can impact the curvature, surface and line tension of the ER, thereby impacting LD biogenesis. Two well-known regulators of LD formation, FIT2/FITM2 and seipin, have both been implicated in controlling the metabolism and/or distribution of non-bilayer lipids. We summarize and integrate these recent advances and propose that non-bilayer lipids may play a critical role in each step of LD biogenesis.
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431
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Malden D, Lacey B, Emberson J, Karpe F, Allen N, Bennett D, Lewington S. Body Fat Distribution and Systolic Blood Pressure in 10,000 Adults with Whole-Body Imaging: UK Biobank and Oxford BioBank. Obesity (Silver Spring) 2019; 27:1200-1206. [PMID: 31081601 PMCID: PMC6618903 DOI: 10.1002/oby.22509] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 03/27/2019] [Indexed: 12/11/2022]
Abstract
OBJECTIVE This study aimed to quantify the associations of regional fat mass and fat-free mass with systolic blood pressure. METHODS This analysis combined individual participant data from two large-scale imaging studies: UK Biobank and Oxford BioBank. In both studies, participants were interviewed and measured, and they underwent dual-energy x-ray absorptiometry imaging. Linear regression was used to relate systolic blood pressure to anthropometric measures of adiposity (BMI, waist circumference, and waist to hip ratio) and dual-energy x-ray absorptiometry-derived measures of body composition (visceral android fat, subcutaneous android fat, subcutaneous gynoid fat, and fat-free mass). RESULTS Among 10,260 participants (mean age 49; 96% white), systolic blood pressure was positively associated with visceral android fat (3.2 mmHg/SD in men; 2.8 mmHg/SD in women) and fat-free mass (1.92 mmHg/SD in men; 1.64 mmHg/SD in women), but there was no evidence of an association with subcutaneous android or gynoid fat. Associations of systolic blood pressure with BMI were slightly steeper than those with waist circumference or waist to hip ratio; these associations remained unchanged following adjustment for fat-free mass, but adjustment for visceral android fat eliminated associations with waist circumference and waist to hip ratio and more than halved associations with BMI. CONCLUSIONS This analysis indicates that visceral fat is the primary etiological component of excess adiposity underlying the development of adiposity-related hypertension.
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Affiliation(s)
- Deborah Malden
- Clinical Trial Service Unit and Epidemiological Studies Unit, Nuffield Department of Population HealthUniversity of OxfordOxfordUK
| | - Ben Lacey
- Clinical Trial Service Unit and Epidemiological Studies Unit, Nuffield Department of Population HealthUniversity of OxfordOxfordUK
| | - Jonathan Emberson
- Clinical Trial Service Unit and Epidemiological Studies Unit, Nuffield Department of Population HealthUniversity of OxfordOxfordUK
- Medical Research Council Population Health Research UnitNuffield Department of Population Health, University of OxfordOxfordUK
| | - Fredrik Karpe
- Oxford Centre for Diabetes, Endocrinology, and MetabolismUniversity of OxfordOxfordUK
- Oxford Biomedical Research Centre, National Institute for Health ResearchOxford University Hospitals Foundation TrustOxfordUK
| | - Naomi Allen
- Clinical Trial Service Unit and Epidemiological Studies Unit, Nuffield Department of Population HealthUniversity of OxfordOxfordUK
- Cancer Epidemiology UnitUniversity of OxfordOxfordUK
| | - Derrick Bennett
- Clinical Trial Service Unit and Epidemiological Studies Unit, Nuffield Department of Population HealthUniversity of OxfordOxfordUK
- Medical Research Council Population Health Research UnitNuffield Department of Population Health, University of OxfordOxfordUK
| | - Sarah Lewington
- Clinical Trial Service Unit and Epidemiological Studies Unit, Nuffield Department of Population HealthUniversity of OxfordOxfordUK
- Medical Research Council Population Health Research UnitNuffield Department of Population Health, University of OxfordOxfordUK
- Oxford Biomedical Research Centre, National Institute for Health ResearchOxford University Hospitals Foundation TrustOxfordUK
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432
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Cao Z, Hao Y, Fung CW, Lee YY, Wang P, Li X, Xie K, Lam WJ, Qiu Y, Tang BZ, Shui G, Liu P, Qu J, Kang BH, Mak HY. Dietary fatty acids promote lipid droplet diversity through seipin enrichment in an ER subdomain. Nat Commun 2019; 10:2902. [PMID: 31263173 PMCID: PMC6602954 DOI: 10.1038/s41467-019-10835-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 06/03/2019] [Indexed: 02/06/2023] Open
Abstract
Exogenous metabolites from microbial and dietary origins have profound effects on host metabolism. Here, we report that a sub-population of lipid droplets (LDs), which are conserved organelles for fat storage, is defined by metabolite-modulated targeting of the C. elegans seipin ortholog, SEIP-1. Loss of SEIP-1 function reduces the size of a subset of LDs while over-expression of SEIP-1 has the opposite effect. Ultrastructural analysis reveals SEIP-1 enrichment in an endoplasmic reticulum (ER) subdomain, which co-purifies with LDs. Analyses of C. elegans and bacterial genetic mutants indicate a requirement of polyunsaturated fatty acids (PUFAs) and microbial cyclopropane fatty acids (CFAs) for SEIP-1 enrichment, as confirmed by dietary supplementation experiments. In mammalian cells, heterologously expressed SEIP-1 engages nascent lipid droplets and promotes their subsequent expansion in a conserved manner. Our results suggest that microbial and polyunsaturated fatty acids serve unexpected roles in regulating cellular fat storage by promoting LD diversity. Lipid droplets (LDs) are fat storage organelles that are initiated and expanded by seipins at ER contact sites. Here the authors show that the C. elegans seipin ortholog SEIP-1 is recruited to these sites by certain dietary fatty acids to support the expansion of a subset of LDs.
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Affiliation(s)
- Zhe Cao
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong SAR, China
| | - Yan Hao
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong SAR, China
| | - Chun Wing Fung
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong SAR, China
| | - Yiu Yiu Lee
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong SAR, China
| | - Pengfei Wang
- School of Life Science, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Xuesong Li
- Biophotonics Research Laboratory, Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR, China
| | - Kang Xie
- Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Wen Jiun Lam
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong SAR, China
| | - Yifei Qiu
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong SAR, China
| | - Ben Zhong Tang
- Department of Chemistry, The Hong Kong University of Science and Technology, Hong Kong SAR, China
| | - Guanghou Shui
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Pingsheng Liu
- Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Jianan Qu
- Biophotonics Research Laboratory, Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR, China
| | - Byung-Ho Kang
- School of Life Science, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Ho Yi Mak
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong SAR, China.
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433
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Huang L, Ye Z, Lu J, Kong C, Zhu Q, Huang B, Wang Z, Xu L, Deng Q, Gong J, Liu P. Effects of fat distribution on lung function in young adults. J Physiol Anthropol 2019; 38:7. [PMID: 31234934 PMCID: PMC6591837 DOI: 10.1186/s40101-019-0198-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 05/23/2019] [Indexed: 02/08/2023] Open
Abstract
Aims To study the associations between fat distribution and lung functions in healthy subjects of young adults and to explore potential gender difference in these correlations. Methods A total of 2101 adult participants were recruited. Height, weight, and vital capacity index (VCI) were measured and recorded according to the national physical fitness test standard. Body compositions, including body mass index (BMI), body fat percentage (BFP), waist-to-hip ratio (WHR), fat-free mass (FFM), trunk muscle mass (TMM), fat mass (FM), visceral fat area (VFA), visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT), were conducted using body composition analyzer. Data were analyzed by SPSS 20.0 software. Results We found that male participants showed significantly higher BMI, WHR, FFM, TMM, VFA, and VCI, but lower FM, BFP, and SAT in comparison with women. However, there was no significant difference in VAT between the male and female. Lung functions represented by VCI were negatively correlated with FM, VAT, SAT, and VFA for both men and women (r < 0; P < 0.05). Among these negative correlations, VCI was more inversely correlated with VFA for men but with SAT for women, respectively. After dividing the whole populations by BMI, BFP, and WHR, further correlation analysis showed VCI was still more negatively correlated with VFA for all male subgroups (r < 0; P < 0.05). On the contrary, VCI was more negatively correlated with SAT in BMI-underweight, BMI-normal, BFP-low fat, BFP-normal fat, WHR-normal, and WHR-obese subgroups (r < 0; P < 0.05), while VFA and VAT was more inversely correlated with VCI in BMI- and BFP-overweight+obese subgroups (r < 0; P < 0.05). Conclusions Fat accumulation is highly associated with the vital capacity index in young adults. In general, VCI was more negatively correlated with VFA for men but with SAT for women, respectively, in comparison with other tested indices.
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Affiliation(s)
- Liqian Huang
- Department of Anatomy, Guangxi Medical University, No. 22 Shuangyong Road, Nanning, 530021, Guangxi, China
| | - Ziliang Ye
- Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Jingjing Lu
- Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Cunqing Kong
- Department of Anatomy, Guangxi Medical University, No. 22 Shuangyong Road, Nanning, 530021, Guangxi, China
| | - Qingqing Zhu
- Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Binbin Huang
- Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Zerong Wang
- Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Lin Xu
- Department of Anatomy, Guangxi Medical University, No. 22 Shuangyong Road, Nanning, 530021, Guangxi, China
| | - Qiongying Deng
- Department of Anatomy, Guangxi Medical University, No. 22 Shuangyong Road, Nanning, 530021, Guangxi, China
| | - Jiangu Gong
- Department of Anatomy, Guangxi Medical University, No. 22 Shuangyong Road, Nanning, 530021, Guangxi, China
| | - Peng Liu
- Department of Anatomy, Guangxi Medical University, No. 22 Shuangyong Road, Nanning, 530021, Guangxi, China.
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434
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Ahi EP, Richter F, Lecaudey LA, Sefc KM. Gene expression profiling suggests differences in molecular mechanisms of fin elongation between cichlid species. Sci Rep 2019; 9:9052. [PMID: 31227799 PMCID: PMC6588699 DOI: 10.1038/s41598-019-45599-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 06/11/2019] [Indexed: 01/09/2023] Open
Abstract
Comparative analyses of gene regulation inform about the molecular basis of phenotypic trait evolution. Here, we address a fin shape phenotype that evolved multiple times independently across teleost fish, including several species within the family Cichlidae. In a previous study, we proposed a gene regulatory network (GRN) involved in the formation and regeneration of conspicuous filamentous elongations adorning the unpaired fins of the Neolamprologus brichardi. Here, we tested the members of this network in the blockhead cichlid, Steatocranus casuarius, which displays conspicuously elongated dorsal and moderately elongated anal fins. Our study provided evidence for differences in the anatomy of fin elongation and suggested gene regulatory divergence between the two cichlid species. Only a subset of the 20 genes tested in S. casuarius showed the qPCR expression patterns predicted from the GRN identified in N. brichardi, and several of the gene-by-gene expression correlations differed between the two cichlid species. In comparison to N. brichardi, gene expression patterns in S. casuarius were in better (but not full) agreement with gene regulatory interactions inferred in zebrafish. Within S. casuarius, the dorsoventral asymmetry in ornament expression was accompanied by differences in gene expression patterns, including potential regulatory differentiation, between the anal and dorsal fin.
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Affiliation(s)
- Ehsan Pashay Ahi
- Institute of Biology, University of Graz, Universitätsplatz 2, A-8010, Graz, Austria. .,Department of Comparative Physiology, Uppsala University, Norbyvägen 18A, SE-75 236, Uppsala, Sweden.
| | - Florian Richter
- Institute of Biology, University of Graz, Universitätsplatz 2, A-8010, Graz, Austria
| | | | - Kristina M Sefc
- Institute of Biology, University of Graz, Universitätsplatz 2, A-8010, Graz, Austria
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435
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Chang CL, Weigel AV, Ioannou MS, Pasolli HA, Xu CS, Peale DR, Shtengel G, Freeman M, Hess HF, Blackstone C, Lippincott-Schwartz J. Spastin tethers lipid droplets to peroxisomes and directs fatty acid trafficking through ESCRT-III. J Cell Biol 2019; 218:2583-2599. [PMID: 31227594 PMCID: PMC6683741 DOI: 10.1083/jcb.201902061] [Citation(s) in RCA: 123] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 04/29/2019] [Accepted: 05/28/2019] [Indexed: 12/22/2022] Open
Abstract
Lipid droplets (LDs) are neutral lipid storage organelles that transfer lipids to various organelles including peroxisomes. Here, we show that the hereditary spastic paraplegia protein M1 Spastin, a membrane-bound AAA ATPase found on LDs, coordinates fatty acid (FA) trafficking from LDs to peroxisomes through two interrelated mechanisms. First, M1 Spastin forms a tethering complex with peroxisomal ABCD1 to promote LD-peroxisome contact formation. Second, M1 Spastin recruits the membrane-shaping ESCRT-III proteins IST1 and CHMP1B to LDs via its MIT domain to facilitate LD-to-peroxisome FA trafficking, possibly through IST1- and CHMP1B-dependent modifications in LD membrane morphology. Furthermore, LD-to-peroxisome FA trafficking mediated by M1 Spastin is required to relieve LDs of lipid peroxidation. M1 Spastin's dual roles in tethering LDs to peroxisomes and in recruiting ESCRT-III components to LD-peroxisome contact sites for FA trafficking may underlie the pathogenesis of diseases associated with defective FA metabolism in LDs and peroxisomes.
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Affiliation(s)
- Chi-Lun Chang
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Aubrey V Weigel
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Maria S Ioannou
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - H Amalia Pasolli
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - C Shan Xu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - David R Peale
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Gleb Shtengel
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Melanie Freeman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Harald F Hess
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Craig Blackstone
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
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436
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Zhang Q, Li X, Cui K, Liu C, Wu M, Prochownik EV, Li Y. The MAP3K13-TRIM25-FBXW7α axis affects c-Myc protein stability and tumor development. Cell Death Differ 2019; 27:420-433. [PMID: 31186535 DOI: 10.1038/s41418-019-0363-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 05/17/2019] [Accepted: 05/28/2019] [Indexed: 12/13/2022] Open
Abstract
c-Myc (Myc) is a master transcription factor that is often deregulated and highly expressed by at least 50% of cancers. In many cases, Myc protein levels correlate with resistance to therapy and poor prognosis. However, effective direct inhibition of Myc by pharmacologic approaches has remained unachievable. Here, we identify MAP3K13 as a positive regulator of Myc to promote tumor development. Our findings show that MAP3K13 upregulation is predictive of poor outcomes in patients with hepatocellular carcinoma (HCC). Mechanistically, MAP3K13 phosphorylates the E3 ubiquitin ligase TRIM25 at Ser12 to decrease its polyubiquitination and proteasomal degradation. This newly stabilized TRIM25 then directly ubiquitinates Lys412 of FBXW7α, a core subunit of the SKP1-Cullin-F-box (SCF) ubiquitin ligase complex involved in Myc ubiquitination, thereby stabilizing Myc. Together, these results reveal a novel regulatory pathway that supervises Myc protein stability via the MAP3K13-TRIM25-FBXW7α signaling axis. In addition, they provide a potential therapeutic target in Myc over-expressing human cancers.
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Affiliation(s)
- Qiang Zhang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, 430072, Wuhan, China.,Medical Research Institute, School of Medicine, Wuhan University, 430071, Wuhan, China
| | - Xu Li
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, 430072, Wuhan, China.,Medical Research Institute, School of Medicine, Wuhan University, 430071, Wuhan, China
| | - Kasa Cui
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, 430072, Wuhan, China.,Medical Research Institute, School of Medicine, Wuhan University, 430071, Wuhan, China
| | - Cheng Liu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, 430072, Wuhan, China.,Medical Research Institute, School of Medicine, Wuhan University, 430071, Wuhan, China
| | - Mingzhi Wu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, 430072, Wuhan, China.,Medical Research Institute, School of Medicine, Wuhan University, 430071, Wuhan, China
| | - Edward V Prochownik
- Division of Hematology/Oncology, Children's Hospital of Pittsburgh of UPMC, The Department of Microbiology and Molecular Genetics and The Hillman Cancer Center of UPMC, The University of Pittsburgh Medical Center, Pittsburgh, PA, 15224, USA
| | - Youjun Li
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, 430072, Wuhan, China. .,Medical Research Institute, School of Medicine, Wuhan University, 430071, Wuhan, China.
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437
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Attenuation of high-fat diet-induced fatty liver through PPARα activation by stevioside. J Funct Foods 2019. [DOI: 10.1016/j.jff.2019.04.034] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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438
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Abstract
PURPOSE OF REVIEW The angiopoietin-like proteins (ANGPTLs), consisting of ANGPTL3, ANGPTL4, and ANGPTL8, have gained significant interest for their role as inhibitors of lipoprotein lipase (LPL) and for their potential as therapeutic targets for correcting dyslipidemia. This review provides an overview of the most relevant new insights on the connection between ANGPTLs, plasma lipids, and coronary artery disease. RECENT FINDINGS Carriers of loss-of-function variants in ANGPTL3 have a reduced risk of coronary artery disease and reduced plasma levels of triglycerides and LDL-C, while carriers of loss-of-function variants in ANGPTL4 have a reduced risk of coronary artery disease and reduced plasma levels of triglycerides and increased HDL-C. There is evidence that carrier status of ANGPTL4 loss-of-function variants may also influence risk of type 2 diabetes. ANGPTL3 is produced in liver and is released as a complex with ANGPTL8 to suppress LPL activity in fat and muscle tissue. ANGPTL4 is produced by numerous tissues and likely mainly functions as a locally released LPL inhibitor. Both proteins inactivate LPL by catalyzing the unfolding of the hydrolase domain in LPL and by promoting the cleavage of LPL. Antisense oligonucleotide and monoclonal antibody-based inactivation of ANGPTL3 reduce plasma triglyceride and LDL-C levels in human volunteers and suppress atherosclerosis in mouse models. SUMMARY ANGPTL3/ANGPTL8 and ANGPTL4 together assure the appropriate distribution of plasma triglycerides across tissues during different physiological conditions. Large-scale genetic studies provide strong rationale for continued research efforts to pharmacologically inactivate ANGPTL3 and possibly ANGPTL4 to reduce plasma lipids and coronary artery disease risk.
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Affiliation(s)
- Sander Kersten
- Nutrition, Metabolism and Genomics Group, Division of Human Nutrition and Health, Wageningen University, Wageningen, the Netherlands
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439
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Jackson CL. Lipid droplet biogenesis. Curr Opin Cell Biol 2019; 59:88-96. [PMID: 31075519 DOI: 10.1016/j.ceb.2019.03.018] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 03/24/2019] [Accepted: 03/29/2019] [Indexed: 11/18/2022]
Abstract
Lipid droplets (LDs) store neutral lipids in their core as an energy source when nutrients are scarce. The center of an LD is hydrophobic, and hence it is surrounded by a phospholipid monolayer, unlike other organelles that have an aqueous interior and are bounded by a phospholipid bilayer. LDs arise from the ER, where neutral lipid synthesis enzymes are localized. A combination of biophysical analysis and modeling, in vitro reconstitution and cell biological analyses has provided a great deal of information over the past few years on the process of LD biogenesis from the ER. In addition to lipid composition, four protein families (seipin proteins, perilipins, FIT proteins and ER shaping proteins) are crucial for LD biogenesis. Recent studies have shown that LDs preferentially arise, along with peroxisomes, at special ER sites marked by the reticulon-like Pex30/MCTP2 protein. New functions for perilipins and FIT family proteins have been uncovered, and the cryo-electron microscopy structure of seipin coupled with high resolution imaging in cells has provided a more comprehensive picture of its function in LD biogenesis. Seipin, along with other proteins such as Rab18 and its effector NRZ, have been shown to carry out their functions at least in part through regulation of ER-LD contact sites, whose establishment and maintenance have emerged as an essential component of LD biogenesis and maturation.
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Affiliation(s)
- Catherine L Jackson
- Institut Jacques Monod, UMR7592 CNRS Université Paris-Diderot, Sorbonne Paris Cité, Paris, France.
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440
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Orang AV, Petersen J, McKinnon RA, Michael MZ. Micromanaging aerobic respiration and glycolysis in cancer cells. Mol Metab 2019; 23:98-126. [PMID: 30837197 PMCID: PMC6479761 DOI: 10.1016/j.molmet.2019.01.014] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 01/22/2019] [Accepted: 01/30/2019] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Cancer cells possess a common metabolic phenotype, rewiring their metabolic pathways from mitochondrial oxidative phosphorylation to aerobic glycolysis and anabolic circuits, to support the energetic and biosynthetic requirements of continuous proliferation and migration. While, over the past decade, molecular and cellular studies have clearly highlighted the association of oncogenes and tumor suppressors with cancer-associated glycolysis, more recent attention has focused on the role of microRNAs (miRNAs) in mediating this metabolic shift. Accumulating studies have connected aberrant expression of miRNAs with direct and indirect regulation of aerobic glycolysis and associated pathways. SCOPE OF REVIEW This review discusses the underlying mechanisms of metabolic reprogramming in cancer cells and provides arguments that the earlier paradigm of cancer glycolysis needs to be updated to a broader concept, which involves interconnecting biological pathways that include miRNA-mediated regulation of metabolism. For these reasons and in light of recent knowledge, we illustrate the relationships between metabolic pathways in cancer cells. We further summarize our current understanding of the interplay between miRNAs and these metabolic pathways. This review aims to highlight important metabolism-associated molecular components in the hunt for selective preventive and therapeutic treatments. MAJOR CONCLUSIONS Metabolism in cancer cells is influenced by driver mutations but is also regulated by posttranscriptional gene silencing. Understanding the nuanced regulation of gene expression in these cells and distinguishing rapid cellular responses from chronic adaptive mechanisms provides a basis for rational drug design and novel therapeutic strategies.
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Affiliation(s)
- Ayla V Orang
- Flinders Centre for Innovation in Cancer, Flinders University, Flinders Medical Centre, Adelaide, South Australia 5042, Australia.
| | - Janni Petersen
- Flinders Centre for Innovation in Cancer, Flinders University, Flinders Medical Centre, Adelaide, South Australia 5042, Australia.
| | - Ross A McKinnon
- Flinders Centre for Innovation in Cancer, Flinders University, Flinders Medical Centre, Adelaide, South Australia 5042, Australia.
| | - Michael Z Michael
- Flinders Centre for Innovation in Cancer, Flinders University, Flinders Medical Centre, Adelaide, South Australia 5042, Australia.
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441
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Nettebrock NT, Bohnert M. Born this way - Biogenesis of lipid droplets from specialized ER subdomains. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1865:158448. [PMID: 31028912 DOI: 10.1016/j.bbalip.2019.04.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 12/20/2018] [Accepted: 01/06/2019] [Indexed: 01/21/2023]
Abstract
Both the endoplasmic reticulum (ER) and lipid droplets (LDs) are key players in lipid handling. In addition to this functional connection, the two organelles are also tightly linked due to the fact that the ER is the birthplace of LDs. LDs have an atypical architecture, consisting of a neutral lipid core that is covered by a phospholipid monolayer. LD biogenesis starts with neutral lipid synthesis in the ER membrane and formation of small neutral lipid lenses between its leaflets, followed by budding of mature LDs toward the cytosol. Several ER proteins have been identified that are required for efficient LD formation, among them seipin, Pex30, and FIT2. Recent evidence indicates that these LD biogenesis factors might cooperate with specific lipids, thus generating ER subdomains optimized for LD assembly. Intriguingly, LD biogenesis reacts dynamically to nutrient stress, resulting in a spatial reorganization of LD formation in the ER.
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Affiliation(s)
- Niclas T Nettebrock
- Institute of Cell Dynamics and Imaging, University of Münster, Von-Esmarch-Str. 56, 48149 Münster, Germany; Cells-in-Motion Cluster of Excellence (EXC 1003 - CiM), University of Münster, Germany
| | - Maria Bohnert
- Institute of Cell Dynamics and Imaging, University of Münster, Von-Esmarch-Str. 56, 48149 Münster, Germany; Cells-in-Motion Cluster of Excellence (EXC 1003 - CiM), University of Münster, Germany.
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442
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Lotta LA, Mokrosiński J, Mendes de Oliveira E, Li C, Sharp SJ, Luan J, Brouwers B, Ayinampudi V, Bowker N, Kerrison N, Kaimakis V, Hoult D, Stewart ID, Wheeler E, Day FR, Perry JRB, Langenberg C, Wareham NJ, Farooqi IS. Human Gain-of-Function MC4R Variants Show Signaling Bias and Protect against Obesity. Cell 2019; 177:597-607.e9. [PMID: 31002796 PMCID: PMC6476272 DOI: 10.1016/j.cell.2019.03.044] [Citation(s) in RCA: 164] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 02/25/2019] [Accepted: 03/22/2019] [Indexed: 12/13/2022]
Abstract
The melanocortin 4 receptor (MC4R) is a G protein-coupled receptor whose disruption causes obesity. We functionally characterized 61 MC4R variants identified in 0.5 million people from UK Biobank and examined their associations with body mass index (BMI) and obesity-related cardiometabolic diseases. We found that the maximal efficacy of β-arrestin recruitment to MC4R, rather than canonical Gαs-mediated cyclic adenosine-monophosphate production, explained 88% of the variance in the association of MC4R variants with BMI. While most MC4R variants caused loss of function, a subset caused gain of function; these variants were associated with significantly lower BMI and lower odds of obesity, type 2 diabetes, and coronary artery disease. Protective associations were driven by MC4R variants exhibiting signaling bias toward β-arrestin recruitment and increased mitogen-activated protein kinase pathway activation. Harnessing β-arrestin-biased MC4R signaling may represent an effective strategy for weight loss and the treatment of obesity-related cardiometabolic diseases.
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MESH Headings
- Adult
- Aged
- Body Mass Index
- Coronary Artery Disease/complications
- Coronary Artery Disease/metabolism
- Coronary Artery Disease/pathology
- Cyclic AMP/metabolism
- Databases, Factual
- Diabetes Mellitus, Type 2/complications
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/pathology
- Female
- GTP-Binding Protein alpha Subunits, Gs/metabolism
- Gain of Function Mutation/genetics
- Genetic Predisposition to Disease
- Genotype
- Humans
- Male
- Middle Aged
- Obesity/complications
- Obesity/metabolism
- Obesity/pathology
- Polymorphism, Single Nucleotide
- Receptor, Melanocortin, Type 4/chemistry
- Receptor, Melanocortin, Type 4/genetics
- Receptor, Melanocortin, Type 4/metabolism
- Signal Transduction
- beta-Arrestins/metabolism
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Affiliation(s)
- Luca A Lotta
- University of Cambridge MRC Epidemiology Unit, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK.
| | - Jacek Mokrosiński
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Edson Mendes de Oliveira
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Chen Li
- University of Cambridge MRC Epidemiology Unit, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Stephen J Sharp
- University of Cambridge MRC Epidemiology Unit, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Jian'an Luan
- University of Cambridge MRC Epidemiology Unit, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Bas Brouwers
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Vikram Ayinampudi
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Nicholas Bowker
- University of Cambridge MRC Epidemiology Unit, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Nicola Kerrison
- University of Cambridge MRC Epidemiology Unit, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Vasileios Kaimakis
- University of Cambridge MRC Epidemiology Unit, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Diana Hoult
- University of Cambridge MRC Epidemiology Unit, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Isobel D Stewart
- University of Cambridge MRC Epidemiology Unit, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Eleanor Wheeler
- University of Cambridge MRC Epidemiology Unit, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Felix R Day
- University of Cambridge MRC Epidemiology Unit, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - John R B Perry
- University of Cambridge MRC Epidemiology Unit, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Claudia Langenberg
- University of Cambridge MRC Epidemiology Unit, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Nicholas J Wareham
- University of Cambridge MRC Epidemiology Unit, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - I Sadaf Farooqi
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK.
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443
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Lee J, Ridgway ND. Substrate channeling in the glycerol-3-phosphate pathway regulates the synthesis, storage and secretion of glycerolipids. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1865:158438. [PMID: 30959116 DOI: 10.1016/j.bbalip.2019.03.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 03/26/2019] [Accepted: 03/27/2019] [Indexed: 01/16/2023]
Abstract
The successive acylation of glycerol-3-phosphate (G3P) by glycerol-3-phosphate acyltransferases and acylglycerol-3-phosphate acyltransferases produces phosphatidic acid (PA), a precursor for CDP-diacylglycerol-dependent phospholipid synthesis. PA is further dephosphorylated by LIPINs to produce diacylglycerol (DG), a substrate for the synthesis of triglyceride (TG) by DG acyltransferases and a precursor for phospholipid synthesis via the CDP-choline and CDP-ethanolamine (Kennedy) pathways. The channeling of fatty acids into TG for storage in lipid droplets and secretion in lipoproteins or phospholipids for membrane biogenesis is dependent on isoform expression, activity and localization of G3P pathway enzymes, as well as dietary and hormonal and tissue-specific factors. Here, we review the mechanisms that control partitioning of substrates into lipid products of the G3P pathway.
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Affiliation(s)
- Jonghwa Lee
- Atlantic Research Center, Depts. of Pediatrics and Biochemistry & Molecular Biology, Dalhousie University, Halifax, NS, Canada
| | - Neale D Ridgway
- Atlantic Research Center, Depts. of Pediatrics and Biochemistry & Molecular Biology, Dalhousie University, Halifax, NS, Canada.
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444
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Behrendt L, Kurth I, Kaether C. A disease causing ATLASTIN 3 mutation affects multiple endoplasmic reticulum-related pathways. Cell Mol Life Sci 2019; 76:1433-1445. [PMID: 30666337 PMCID: PMC6420906 DOI: 10.1007/s00018-019-03010-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 01/09/2019] [Accepted: 01/10/2019] [Indexed: 12/01/2022]
Abstract
Atlastins (ATLs) are membrane-bound GTPases involved in shaping of the endoplasmic reticulum (ER). Mutations in ATL1 and ATL3 cause spastic paraplegia and hereditary sensory neuropathy. We here show that the sensory neuropathy causing ATL3 Y192C mutation reduces the complexity of the tubular ER-network. ATL3 Y192C delays ER-export by reducing the number of ER exit sites, reduces autophagy, fragments the Golgi and causes malformation of the nucleus. In cultured primary neurons, ATL3 Y192C does not localize to the growing axon, resulting in axon growth deficits. Patient-derived fibroblasts possess a tubular ER with reduced complexity and have a reduced number of autophagosomes. The data suggest that the disease-causing ATL3 Y192C mutation affects multiple ER-related pathways, possibly as a consequence of the distorted ER morphology.
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Affiliation(s)
- Laura Behrendt
- Leibniz Institut für Alternsforschung-Fritz Lipmann Institut, Beutenbergstr. 11, 07745, Jena, Germany
| | - Ingo Kurth
- Institute of Human Genetics, Medical Faculty, RWTH Aachen University, 52074, Aachen, Germany
| | - Christoph Kaether
- Leibniz Institut für Alternsforschung-Fritz Lipmann Institut, Beutenbergstr. 11, 07745, Jena, Germany.
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445
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Nagarajan SR, Paul-Heng M, Krycer JR, Fazakerley DJ, Sharland AF, Hoy AJ. Lipid and glucose metabolism in hepatocyte cell lines and primary mouse hepatocytes: a comprehensive resource for in vitro studies of hepatic metabolism. Am J Physiol Endocrinol Metab 2019; 316:E578-E589. [PMID: 30694691 DOI: 10.1152/ajpendo.00365.2018] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The liver is a critical tissue for maintaining glucose, fatty acid, and cholesterol homeostasis. Primary hepatocytes represent the gold standard for studying the mechanisms controlling hepatic glucose, lipid, and cholesterol metabolism in vitro. However, access to primary hepatocytes can be limiting, and therefore, other immortalized hepatocyte models are commonly used. Here, we describe substrate metabolism of cultured AML12, IHH, and PH5CH8 cells, hepatocellular carcinoma-derived HepG2s, and primary mouse hepatocytes (PMH) to identify which of these cell lines most accurately phenocopy PMH basal and insulin-stimulated metabolism. Insulin-stimulated glucose metabolism in PH5CH8 cells, and to a lesser extent AML12 cells, responded most similarly to PMH. Notably, glucose incorporation in HepG2 cells were 14-fold greater than PMH. The differences in glucose metabolic activity were not explained by differential protein expression of key regulators of these pathways, for example glycogen synthase and glycogen content. In contrast, fatty acid metabolism in IHH cells was the closest to PMHs, yet insulin-responsive fatty acid metabolism in AML12 and HepG2 cells was most similar to PMH. Finally, incorporation of acetate into intracellular-free cholesterol was comparable for all cells to PMH; however, insulin-stimulated glucose conversion into lipids and the incorporation of acetate into intracellular cholesterol esters were strikingly different between PMHs and all tested cell lines. In general, AML12 cells most closely phenocopied PMH in vitro energy metabolism. However, the cell line most representative of PMHs differed depending on the mode of metabolism being investigated, and so careful consideration is needed in model selection.
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Affiliation(s)
- Shilpa R Nagarajan
- Discipline of Physiology, School of Medical Sciences & Bosch Institute, Charles Perkins Centre, Faculty of Medicine and Health, The University of Sydney , New South Wales , Australia
| | - Moumita Paul-Heng
- Discipline of Surgery, Central Clinical School & Bosch Institute, Charles Perkins Centre, Faculty of Medicine and Health, University of Sydney , New South Wales , Australia
| | - James R Krycer
- School of Life and Environmental Sciences, Charles Perkins Centre, Faculty of Science, The University of Sydney , New South Wales , Australia
| | - Daniel J Fazakerley
- School of Life and Environmental Sciences, Charles Perkins Centre, Faculty of Science, The University of Sydney , New South Wales , Australia
| | - Alexandra F Sharland
- Discipline of Surgery, Central Clinical School & Bosch Institute, Charles Perkins Centre, Faculty of Medicine and Health, University of Sydney , New South Wales , Australia
| | - Andrew J Hoy
- Discipline of Physiology, School of Medical Sciences & Bosch Institute, Charles Perkins Centre, Faculty of Medicine and Health, The University of Sydney , New South Wales , Australia
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446
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Schrul B, Schliebs W. Intracellular communication between lipid droplets and peroxisomes: the Janus face of PEX19. Biol Chem 2019; 399:741-749. [PMID: 29500918 DOI: 10.1515/hsz-2018-0125] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 02/23/2018] [Indexed: 02/06/2023]
Abstract
In order to adapt to environmental changes, such as nutrient availability, cells have to orchestrate multiple metabolic pathways, which are catalyzed in distinct specialized organelles. Lipid droplets (LDs) and peroxisomes are both endoplasmic reticulum (ER)-derived organelles that fulfill complementary functions in lipid metabolism: Upon nutrient supply, LDs store metabolic energy in the form of neutral lipids and, when energy is needed, supply fatty acids for oxidation in peroxisomes and mitochondria. How these organelles communicate with each other for a concerted metabolic output remains a central question. Here, we summarize recent insights into the biogenesis and function of LDs and peroxisomes with emphasis on the role of PEX19 in these processes.
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Affiliation(s)
- Bianca Schrul
- Medical Biochemistry and Molecular Biology, Center for Molecular Signaling (PZMS), Faculty of Medicine, Saarland University, Kirrberger Str. 100, D-66421 Homburg/Saar, Germany
| | - Wolfgang Schliebs
- Institute of Biochemistry and Pathobiochemistry, Department of Systems Biochemistry, Faculty of Medicine, Ruhr University Bochum, D-44780 Bochum, Germany
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447
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Selvam S, Ramaian Santhaseela A, Ganesan D, Rajasekaran S, Jayavelu T. Autophagy inhibition by biotin elicits endoplasmic reticulum stress to differentially regulate adipocyte lipid and protein synthesis. Cell Stress Chaperones 2019; 24:343-350. [PMID: 30648232 PMCID: PMC6439007 DOI: 10.1007/s12192-018-00967-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 12/21/2018] [Accepted: 12/26/2018] [Indexed: 12/12/2022] Open
Abstract
Biotin is an indispensable adipogenic agent, and its ability to coordinate carbohydrate, lipid, and amino acid metabolism sensitizes insulin signaling in adipocytes. This enables the organism to adapt and survive under nutrient stress by synthesis and storage of lipids. Biotin deficiency mimics insulin resistance with alterations in cellular intermediary metabolism. Though the mechanism of lipogenesis is well established across cell types, considering its predisposition to accumulate only lipids, it is necessary to elucidate the mechanism that minimizes the effects of biotin on adipocyte protein synthesis. In order to determine the differential metabolic phenotype by biotin, the primary cultures of adipocytes were induced to differentiate in the presence and absence of excess biotin. Serum pre-incubated with avidin was used to limit biotin availability in cultured cells. Biotin restricts cellular signaling associated with protein synthesis without altering total protein content. The decline in autophagy elicits endoplasmic reticulum stress to inhibit protein synthesis by eIF2α phosphorylation possibly via accumulation of misfolded/long-lived proteins. Furthermore, the compensatory increase in Unc51 like autophagy activating kinase 1 possibly competes with eukaryotic initiation factor 4E-binding protein 1 and ribosomal p70 S6kinase phosphorylation by mechanistic targets of rapamycin complex 1 to uncouple its effect on protein synthesis. In conclusion, autophagy inhibition by biotin uncouples protein synthesis to promote lipogenesis by eliciting endoplasmic reticulum stress and differential phosphorylation of mechanistic targets of rapamycin complex 1 substrates.
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448
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Abstract
Lipid droplets are storage organelles at the centre of lipid and energy homeostasis. They have a unique architecture consisting of a hydrophobic core of neutral lipids, which is enclosed by a phospholipid monolayer that is decorated by a specific set of proteins. Originating from the endoplasmic reticulum, lipid droplets can associate with most other cellular organelles through membrane contact sites. It is becoming apparent that these contacts between lipid droplets and other organelles are highly dynamic and coupled to the cycles of lipid droplet expansion and shrinkage. Importantly, lipid droplet biogenesis and degradation, as well as their interactions with other organelles, are tightly coupled to cellular metabolism and are critical to buffer the levels of toxic lipid species. Thus, lipid droplets facilitate the coordination and communication between different organelles and act as vital hubs of cellular metabolism.
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Affiliation(s)
- James A Olzmann
- Department of Nutritional Sciences and Toxicology, University of California-Berkeley, Berkeley, CA, USA.
| | - Pedro Carvalho
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
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449
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Boutry M, Morais S, Stevanin G. Update on the Genetics of Spastic Paraplegias. Curr Neurol Neurosci Rep 2019; 19:18. [DOI: 10.1007/s11910-019-0930-2] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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450
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Chorlay A, Thiam AR. An Asymmetry in Monolayer Tension Regulates Lipid Droplet Budding Direction. Biophys J 2019; 114:631-640. [PMID: 29414709 DOI: 10.1016/j.bpj.2017.12.014] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 11/22/2017] [Accepted: 12/11/2017] [Indexed: 01/19/2023] Open
Abstract
Cells store excess energy in the form of neutral lipids that are synthesized and encapsulated within the endoplasmic reticulum intermonolayer space. The lipids next demix to form lipid droplets (LDs), which, surprisingly, bud off mostly toward the cytosol. This directional LD formation is critical to energy metabolism, but its mechanism remains poorly understood. Here, we reconstituted the LD formation topology by embedding artificial LDs into the intermonolayer space of bilayer vesicles. We provide experimental evidence that the droplet behavior in the membrane is recapitulated by the physics of three-phase wetting systems, dictated by the equilibrium of surface tensions. We thereupon determined that slight tension asymmetries between the membrane monolayers regulate the droplet budding side. A differential regulation of lipid or protein composition around a forming LD can generate a monolayer tension asymmetry that will determine the LD budding side. Our results offer, to our knowledge, new insights on how the proteins might regulate LD formation side by generating a monolayer tension asymmetry.
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Affiliation(s)
- Aymeric Chorlay
- Laboratoire de Physique Statistique, Ecole Normale Supérieure, PSL Research University, Sorbonne Université, UPMC Université Paris 06, Université Paris Diderot, CNRS, Paris, France
| | - Abdou Rachid Thiam
- Laboratoire de Physique Statistique, Ecole Normale Supérieure, PSL Research University, Sorbonne Université, UPMC Université Paris 06, Université Paris Diderot, CNRS, Paris, France.
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