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Castanho Martins M, Dixon ED, Lupo G, Claudel T, Trauner M, Rombouts K. Role of PNPLA3 in Hepatic Stellate Cells and Hepatic Cellular Crosstalk. Liver Int 2025; 45:e16117. [PMID: 39394864 PMCID: PMC11891384 DOI: 10.1111/liv.16117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2024] [Revised: 09/16/2024] [Accepted: 09/17/2024] [Indexed: 10/14/2024]
Abstract
AIMS Since its discovery, the patatin-like phospholipase domain containing 3 (PNPLA3) (rs738409 C>G p.I148M) variant has been studied extensively to unravel its molecular function. Although several studies proved a causal relationship between the PNPLA3 I148M variant and MASLD development and particularly fibrosis, the pathological mechanisms promoting this phenotype have not yet been fully clarified. METHODS We summarise the latest data regarding the PNPLA3 I148M variant in hepatic stellate cells (HSCs) activation and macrophage biology or the path to inflammation-induced fibrosis. RESULTS Elegant but contradictory studies have ascribed PNPLA3 a hydrolase or an acyltransferase function. The PNPLA3 I148M results in hepatic lipid accumulation, which predisposes the hepatocyte to lipotoxicity and lipo-apoptosis, producing DAMPs, cytokines and chemokines leading to recruitment and activation of macrophages and HSCs, propagating fibrosis. Recent studies showed that the PNPLA3 I148M variant alters HSCs biology via attenuation of PPARγ, AP-1, LXRα and TGFβ activity and signalling. CONCLUSIONS The advent of refined techniques in isolating HSCs has made PNPLA3's direct role in HSCs for liver fibrosis development more apparent. However, many other mechanisms still need detailed investigations.
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Affiliation(s)
- Maria Castanho Martins
- Regenerative Medicine and Fibrosis Group, Institute for Liver and Digestive HealthUniversity College London, Royal Free CampusLondonUK
| | - Emmanuel Dauda Dixon
- Hans Popper Laboratory of Molecular Hepatology, Department of Internal Medicine IIIMedical University of ViennaViennaAustria
| | - Giulia Lupo
- Regenerative Medicine and Fibrosis Group, Institute for Liver and Digestive HealthUniversity College London, Royal Free CampusLondonUK
| | - Thierry Claudel
- Hans Popper Laboratory of Molecular Hepatology, Department of Internal Medicine IIIMedical University of ViennaViennaAustria
| | - Michael Trauner
- Hans Popper Laboratory of Molecular Hepatology, Department of Internal Medicine IIIMedical University of ViennaViennaAustria
| | - Krista Rombouts
- Regenerative Medicine and Fibrosis Group, Institute for Liver and Digestive HealthUniversity College London, Royal Free CampusLondonUK
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Cherubini A, Casirati E, Tomasi M, Valenti L. PNPLA3 as a therapeutic target for fatty liver disease: the evidence to date. Expert Opin Ther Targets 2021; 25:1033-1043. [PMID: 34904923 DOI: 10.1080/14728222.2021.2018418] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
INTRODUCTION An interaction between metabolic triggers and inherited predisposition underpins the development and progression of non alcoholic fatty liver disease (NAFLD) and fatty liver disease in general. Among the specific NAFLD risk variants, PNPLA3 rs738409 C>G, encoding for the p.I148M protein variant, accounts for the largest fraction of liver disease heritability and is being intensively scrutinized. It promotes intrahepatic lipid accumulation and is associated with lipotoxicity and the more severe phenotypes, including fibrosis and carcinogenesis. Therefore, PNPLA3 appears as an appealing therapeutic target to counter NAFLD progression. AREAS COVERED The scope of this review is to briefly describe the PNPLA3 gene and protein function before discussing therapeutic approaches for fatty liver aiming at this target. Literature review was carried out searching through PubMed and clinicaltrials.gov website and focusing on the most recent works and reviews. EXPERT OPINION The main therapeutic strategies under development for NAFLD have shown variable efficacy and side-effects likely due to disease heterogeneity and lack of engagement of the main pathogenic drivers of liver disease. To overcome these limitations, new strategies are becoming available for targeting PNPLA3 p.I148M, responsible for a large fraction of disease susceptibility.
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Affiliation(s)
- Alessandro Cherubini
- Precision Medicine - Department of Transfusion Medicine and Hematology, Fondazione Irccs Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Elia Casirati
- Department of Pathophysiology and Transplantation, Università Degli Studi Di Milano, Milan, Italy
| | - Melissa Tomasi
- Precision Medicine - Department of Transfusion Medicine and Hematology, Fondazione Irccs Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Luca Valenti
- Precision Medicine - Department of Transfusion Medicine and Hematology, Fondazione Irccs Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.,Department of Pathophysiology and Transplantation, Università Degli Studi Di Milano, Milan, Italy
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3
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Murray JK, Long J, Liu L, Singh S, Pruitt D, Ollmann M, Swearingen E, Hardy M, Homann O, Wu B, Holder JR, Sham K, Herberich B, Lo MC, Dou H, Shkumatov A, Florio M, Rulifson IC. Identification and Optimization of a Minor Allele-Specific Small Interfering RNA to Prevent PNPLA3 I148M-Driven Nonalcoholic Fatty Liver Disease. Nucleic Acid Ther 2021; 31:324-340. [PMID: 34297902 DOI: 10.1089/nat.2021.0026] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Human genome wide association studies confirm the association of the rs738409 single nucleotide polymorphism (SNP) in the gene encoding protein patatin like phospholipase domain containing 3 (PNPLA3) with nonalcoholic fatty liver disease (NAFLD); the presence of the resulting mutant PNPLA3 I148M protein is a driver of nonalcoholic steatohepatitis (NASH). While Pnpla3-deficient mice do not display an adverse phenotype, the safety of knocking down endogenous wild type PNPLA3 in humans remains unknown. To expand the scope of a potential targeted NAFLD therapeutic to both homozygous and heterozygous PNPLA3 rs738409 populations, we sought to identify a minor allele-specific small interfering RNA (siRNA). Limiting our search to SNP-spanning triggers, a series of chemically modified siRNA were tested in vitro for activity and selectivity toward PNPLA3 rs738409 mRNA. Conjugation of the siRNA to a triantennary N-acetylgalactosamine (GalNAc) ligand enabled in vivo screening using adeno-associated virus to overexpress human PNPLA3I148M versus human PNPLA3I148I in mouse livers. Structure-activity relationship optimization yielded potent and minor allele-specific compounds that achieved high levels of mRNA and protein knockdown of human PNPLA3I148M but not PNPLA3I148I. Testing of the minor allele-specific siRNA in PNPLA3I148M-expressing mice fed a NASH-inducing diet prevented PNPLA3I148M-driven disease phenotypes, thus demonstrating the potential of a precision medicine approach to treating NAFLD.
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Affiliation(s)
- Justin K Murray
- Therapeutic Discovery, Amgen Research, Thousand Oaks, California, USA
| | - Jason Long
- Therapeutic Discovery, Amgen Research, Thousand Oaks, California, USA
| | - Lei Liu
- Cardiometabolic Disorders, Amgen Research, South San Francisco, California, USA
| | - Shivani Singh
- Cardiometabolic Disorders, Amgen Research, South San Francisco, California, USA
| | - Danielle Pruitt
- Cardiometabolic Disorders, Amgen Research, South San Francisco, California, USA
| | - Michael Ollmann
- Genome Analysis Unit, Amgen Research, South San Francisco, California, USA
| | - Elissa Swearingen
- Genome Analysis Unit, Amgen Research, South San Francisco, California, USA
| | - Miki Hardy
- Genome Analysis Unit, Amgen Research, South San Francisco, California, USA
| | - Oliver Homann
- Genome Analysis Unit, Amgen Research, South San Francisco, California, USA
| | - Bin Wu
- Therapeutic Discovery, Amgen Research, Thousand Oaks, California, USA
| | - Jerry Ryan Holder
- Therapeutic Discovery, Amgen Research, Thousand Oaks, California, USA
| | - Kelvin Sham
- Therapeutic Discovery, Amgen Research, Thousand Oaks, California, USA
| | - Brad Herberich
- Therapeutic Discovery, Amgen Research, Thousand Oaks, California, USA
| | - Mei-Chu Lo
- Therapeutic Discovery, Amgen Research, South San Francisco, California, USA
| | - Hui Dou
- Therapeutic Discovery, Amgen Research, South San Francisco, California, USA
| | - Artem Shkumatov
- Translational Safety and Bioanalytical Sciences, Amgen Research, South San Francisco, California, USA
| | - Monica Florio
- Cardiometabolic Disorders, Amgen Research, Thousand Oaks, California, USA
| | - Ingrid C Rulifson
- Cardiometabolic Disorders, Amgen Research, South San Francisco, California, USA
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Dallio M, Romeo M, Gravina AG, Masarone M, Larussa T, Abenavoli L, Persico M, Loguercio C, Federico A. Nutrigenomics and Nutrigenetics in Metabolic- (Dysfunction) Associated Fatty Liver Disease: Novel Insights and Future Perspectives. Nutrients 2021; 13:1679. [PMID: 34063372 PMCID: PMC8156164 DOI: 10.3390/nu13051679] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 05/12/2021] [Accepted: 05/13/2021] [Indexed: 12/12/2022] Open
Abstract
Metabolic- (dysfunction) associated fatty liver disease (MAFLD) represents the predominant hepatopathy and one of the most important systemic, metabolic-related disorders all over the world associated with severe medical and socio-economic repercussions due to its growing prevalence, clinical course (steatohepatitis and/or hepatocellular-carcinoma), and related extra-hepatic comorbidities. To date, no specific medications for the treatment of this condition exist, and the most valid recommendation for patients remains lifestyle change. MAFLD has been associated with metabolic syndrome; its development and progression are widely influenced by the interplay between genetic, environmental, and nutritional factors. Nutrigenetics and nutrigenomics findings suggest nutrition's capability, by acting on the individual genetic background and modifying the specific epigenetic expression as well, to influence patients' clinical outcome. Besides, immunity response is emerging as pivotal in this multifactorial scenario, suggesting the interaction between diet, genetics, and immunity as another tangled network that needs to be explored. The present review describes the genetic background contribution to MAFLD onset and worsening, its possibility to be influenced by nutritional habits, and the interplay between nutrients and immunity as one of the most promising research fields of the future in this context.
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Affiliation(s)
- Marcello Dallio
- Department of Precision Medicine, University of Campania Luigi Vanvitelli, Via S. Pansini 5, 80131 Naples, Italy; (M.R.); (A.G.G.); (C.L.); (A.F.)
| | - Mario Romeo
- Department of Precision Medicine, University of Campania Luigi Vanvitelli, Via S. Pansini 5, 80131 Naples, Italy; (M.R.); (A.G.G.); (C.L.); (A.F.)
| | - Antonietta Gerarda Gravina
- Department of Precision Medicine, University of Campania Luigi Vanvitelli, Via S. Pansini 5, 80131 Naples, Italy; (M.R.); (A.G.G.); (C.L.); (A.F.)
| | - Mario Masarone
- Department of Medicine and Surgery, University of Salerno, Via Allende, 84081 Baronissi, Italy; (M.M.); (M.P.)
| | - Tiziana Larussa
- Department of Health Sciences, University Magna Graecia, viale Europa, 88100 Catanzaro, Italy; (T.L.); (L.A.)
| | - Ludovico Abenavoli
- Department of Health Sciences, University Magna Graecia, viale Europa, 88100 Catanzaro, Italy; (T.L.); (L.A.)
| | - Marcello Persico
- Department of Medicine and Surgery, University of Salerno, Via Allende, 84081 Baronissi, Italy; (M.M.); (M.P.)
| | - Carmelina Loguercio
- Department of Precision Medicine, University of Campania Luigi Vanvitelli, Via S. Pansini 5, 80131 Naples, Italy; (M.R.); (A.G.G.); (C.L.); (A.F.)
| | - Alessandro Federico
- Department of Precision Medicine, University of Campania Luigi Vanvitelli, Via S. Pansini 5, 80131 Naples, Italy; (M.R.); (A.G.G.); (C.L.); (A.F.)
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Pralle RS, Erb SJ, Holdorf HT, White HM. Greater liver PNPLA3 protein abundance in vivo and in vitro supports lower triglyceride accumulation in dairy cows. Sci Rep 2021; 11:2839. [PMID: 33531537 PMCID: PMC7854614 DOI: 10.1038/s41598-021-82233-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 01/14/2021] [Indexed: 02/07/2023] Open
Abstract
Fatty liver syndrome is a prevalent metabolic disorder in peripartum dairy cows that unfavorably impacts lactation performance and health. Patatin-like phospholipase domain-containing protein 3 (PNPLA3) is a lipase that plays a central role in human non-alcoholic fatty liver disease etiology but has received limited attention in bovine fatty liver research. Thus, we investigated the relationship between tissue PNPLA3 expression and liver triglyceride accumulation in vivo via a ketosis induction protocol in multiparous dairy cows peripartum, as well as in vitro via small interfering RNA knockdown of PNPLA3 mRNA expression in bovine primary hepatocytes. Results demonstrated a negative association (P = 0.04) between liver PNPLA3 protein abundance and liver triglyceride content in peripartum dairy cows, while adipose PNPLA3 protein abundance was not associated with liver triglyceride content or blood fatty acid concentration. Knockdown of PNPLA3 mRNA resulted in reduced PNPLA3 protein abundance (P < 0.01) and greater liver triglyceride content (P < 0.01). Together, these results suggest greater liver PNPLA3 protein abundance may directly limit liver triglyceride accumulation peripartum, potentially preventing bovine fatty liver or accelerating recovery from fatty liver syndrome.
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Affiliation(s)
- Ryan S Pralle
- Department of Dairy Science, University of Wisconsin-Madison, Madison, 53706, USA
| | - Sophia J Erb
- Department of Dairy Science, University of Wisconsin-Madison, Madison, 53706, USA
| | - Henry T Holdorf
- Department of Dairy Science, University of Wisconsin-Madison, Madison, 53706, USA
| | - Heather M White
- Department of Dairy Science, University of Wisconsin-Madison, 1675 Observatory Drive, Rm 934B, Madison, WI, 53706, USA.
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6
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The role of genetic and epigenetic factors in non alcoholic fatty liver disease (NAFLD) pathogenesis. Meta Gene 2020. [DOI: 10.1016/j.mgene.2020.100647] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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7
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Delik A, Akkız H, Dinçer S. The effect of PNPLA3 polymorphism as gain in function mutation in the pathogenesis of non-alcoholic fatty liver disease. Indian J Gastroenterol 2020; 39:84-91. [PMID: 32333362 DOI: 10.1007/s12664-020-01026-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 02/05/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND Non-alcoholic fatty liver disease (NAFLD) is often associated with metabolic syndrome (type 2 diabetes, hypertension, hypertriglyceridemia, insulin resistance, and obesity). NAFLD is multi-factorial in pathogenesis with some genetic predisposition. The variant patatin-like phospholipase domain-containing protein 3 (PNPLA3) is known to be an independent risk factor for hepatocellular cancer (HCC). The aim of this study was to investigate the role of PNPLA3 polymorphism as the risk factor for NAFLD. METHODOLOGY Patients had histological, ultrasonographic, biopsy evidence of NAFLD (n=248) and 81 controls were studied for PNPLA3 polymorphism. PNPLA3 genotyping was done from peripheral blood DNA by real-time polymerase chain reaction (RT-PCR). RESULTS PNPLA3 genotyping of the groups NAFLD (CC [n = 76], CG [n = 83], GG [n = 89]) and control (CC [n= 42], CG [n = 22], GG [n = 17]) was determined. In the patient group, the G allele was 261 (52.63%) and the C allele was 235 (47.37%), whereas in the control group, the G allele was 56 (34.54%) and the C allele was 106 (65.43%). In our study, 53 out of 174 women had GG allele and 54 out of 155 men had GG allele. CONCLUSION The findings suggest that there is a predominant relationship between men with PNPLA3 I148M variant with NAFLD in women. Patients with NAFLD carrying PNPLA3 rs738409 G>C variant are at higher risk of NAFLD.
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Affiliation(s)
- Anıl Delik
- Department of Gastroenterology, Faculty of Medicine, Çukurova University, 01330, Adana, Turkey. .,Department of Biology, Faculty of Natural and Applied Science, Çukurova University, 01330, Adana, Turkey.
| | - Hikmet Akkız
- Department of Gastroenterology, Faculty of Medicine, Çukurova University, 01330, Adana, Turkey
| | - Sadık Dinçer
- Department of Biology, Faculty of Natural and Applied Science, Çukurova University, 01330, Adana, Turkey
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8
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Rüschenbaum S, Schwarzkopf K, Friedrich-Rust M, Seeger F, Schoelzel F, Martinez Y, Zeuzem S, Bojunga J, Lange CM. Patatin-like phospholipase domain containing 3 variants differentially impact metabolic traits in individuals at high risk for cardiovascular events. Hepatol Commun 2018; 2:798-806. [PMID: 30027138 PMCID: PMC6049070 DOI: 10.1002/hep4.1183] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 03/14/2018] [Accepted: 03/17/2018] [Indexed: 12/16/2022] Open
Abstract
Single nucleotide polymorphism (SNP) rs738409 C>G in the patatin‐like phospholipase domain containing 3 (PNPLA3) gene results in an amino acid exchange from isoleucin to methionine at position I148M of PNPLA3. The expression of this loss‐of‐function mutation leads to impaired hepatocellular triglyceride hydrolysis and is associated with the development of liver steatosis, fibrosis, and hepatocellular carcinoma. In contrast to these well‐established associations, the relationship of the PNPLA3 rs738409 variant with other metabolic traits is incompletely understood. We therefore assessed the association of the PNPLA3 rs738409 genotype with relevant metabolic traits in a prospective study of patients at high risk for cardiovascular events, i.e., patients undergoing coronary angiography. In a total of 270 patients, known associations of the PNPLA3 rs738409 GG genotype with nonalcoholic steatohepatitis and liver fibrosis were confirmed. In addition, we found an association of the PNPLA3 rs738409 G allele with the presence of diabetes (22% versus 28% versus 58% for CC versus CG versus GG genotype, respectively; P = 0.02). In contrast to its association with nonalcoholic fatty liver disease, liver fibrosis, and diabetes, the minor G allele of PNPLA3 rs738409 was inversely associated with total serum cholesterol and low‐density lipoprotein serum levels (P = 0.003 and P = 0.02, respectively). Finally, there was a trend toward an inverse association between the presence of the PNPLA3 rs738409 G allele and significant coronary heart disease. Comparable trends were observed for the transmembrane 6 superfamily member 2 (TM6SF2) 167 K variant, but the sample size was too small to evaluate this rarer variant. Conclusion: The PNPLA3 rs738409 G allele is associated with liver disease but also with a relatively benign cardiovascular risk profile. (Hepatology Communications 2018;2:798‐806)
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Affiliation(s)
- Sabrina Rüschenbaum
- Department of Internal Medicine 1 J.W. Goethe-University Hospital Frankfurt Germany
| | | | | | - Florian Seeger
- Department of Cardiology St. Elisabeth Hospital Ravensburg Germany
| | - Fabian Schoelzel
- Department of Internal Medicine 1 J.W. Goethe-University Hospital Frankfurt Germany
| | - Yolanda Martinez
- Department of Internal Medicine 1 J.W. Goethe-University Hospital Frankfurt Germany
| | - Stefan Zeuzem
- Department of Internal Medicine 1 J.W. Goethe-University Hospital Frankfurt Germany
| | - Jörg Bojunga
- Department of Internal Medicine 1 J.W. Goethe-University Hospital Frankfurt Germany
| | - Christian M Lange
- Department of Internal Medicine 1 J.W. Goethe-University Hospital Frankfurt Germany
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Liu W, Anstee QM, Wang X, Gawrieh S, Gamazon ER, Athinarayanan S, Liu YL, Darlay R, Cordell HJ, Daly AK, Day CP, Chalasani N. Transcriptional regulation of PNPLA3 and its impact on susceptibility to nonalcoholic fatty liver Disease (NAFLD) in humans. Aging (Albany NY) 2017; 9:26-40. [PMID: 27744419 PMCID: PMC5310654 DOI: 10.18632/aging.101067] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 09/28/2016] [Indexed: 12/22/2022]
Abstract
The increased expression of PNPLA3148M leads to hepatosteatosis in mice. This study aims to investigate the genetic control of hepatic PNPLA3 transcription and to explore its impact on NAFLD risk in humans. Through a locus-wide expression quantitative trait loci (eQTL) mapping in two human liver sample sets, a PNPLA3 intronic SNP, rs139051 A>G was identified as a significant eQTL (p = 6.6×10-8) influencing PNPLA3 transcription, with the A allele significantly associated with increased PNPLA3 mRNA. An electrophoresis mobility shift assay further demonstrated that the A allele has enhanced affinity to nuclear proteins than the G allele. The impact of this eQTL on NAFLD risk was further tested in three independent populations. We found that rs139051 did not independently affect the NAFLD risk, whilst rs738409 did not significantly modulate PNPLA3 transcription but was associated with NAFLD risk. The A-G haplotype associated with higher transcription of the disease-risk rs738409 G allele conferred similar risk for NAFLD compared to the G-G haplotype that possesses a lower transcription level. Our study suggests that the pathogenic role of PNPLA3148M in NAFLD is independent of the gene transcription in humans, which may be attributed to the high endogenous transcription level of PNPLA3 gene in human livers.
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Affiliation(s)
- Wanqing Liu
- Department of Medicinal Chemistry and Molecular Medicine, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA
| | - Quentin M Anstee
- Liver Research Group, Institute of Cellular Medicine, The Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Xiaoliang Wang
- Department of Medicinal Chemistry and Molecular Medicine, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA.,Department of General Surgery, Shanghai Jiaotong University Affiliated First People's Hospital, Shanghai, P. R. China
| | - Samer Gawrieh
- Division of Gastroenterology and Hepatology, Indiana Fatty Liver Disease Research Group, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Eric R Gamazon
- Section of Genetic Medicine, Department of Medicine, The University of Chicago, Chicago, IL 60627, USA.,Division of Genetic Medicine, Department of Medicine, Vanderbilt University, Nashville, TN 37235, USA
| | - Shaminie Athinarayanan
- Department of Medicinal Chemistry and Molecular Medicine, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA
| | - Yang-Lin Liu
- Liver Research Group, Institute of Cellular Medicine, The Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Rebecca Darlay
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Heather J Cordell
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Ann K Daly
- Liver Research Group, Institute of Cellular Medicine, The Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Chris P Day
- Liver Research Group, Institute of Cellular Medicine, The Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Naga Chalasani
- Division of Gastroenterology and Hepatology, Indiana Fatty Liver Disease Research Group, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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10
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Abstract
A single-nucleotide polymorphism occurring in the sequence of the human patatin-like phospholipase domain-containing 3 gene (PNPLA3), known as I148M variant, is one of the best characterized and deeply investigated variants in several clinical scenarios, because of its tight correlation with increased risk for developing hepatic steatosis and more aggressive part of the disease spectrum, such as nonalcoholic steatohepatitis, advanced fibrosis and cirrhosis. Further, the I148M variant is positively associated with alcoholic liver diseases, chronic hepatitis C-related cirrhosis and hepatocellular carcinoma. The native gene encodes for a protein that has not yet a fully defined role in liver lipid metabolism and, according to recent observations, seems to be divergently regulated among distinct liver cells type, such as hepatic stellate cells. Therefore, the aim of this review is to collect the latest data regarding PNPLA3 expression in human liver and to analyze the impact of its genetic variant in human hepatic pathologies. Moreover, a description of the current biochemical and metabolic data pertaining to PNPLA3 function in both animal models and in vitro studies is summarized to allow a better understanding of the relevant pathophysiological role of this enzyme in the progression of hepatic diseases.
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Affiliation(s)
- Francesca Virginia Bruschi
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology & Hepatology, Department of Internal Medicine III, Medical University of Vienna, Austria
| | - Matteo Tardelli
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology & Hepatology, Department of Internal Medicine III, Medical University of Vienna, Austria
| | - Thierry Claudel
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology & Hepatology, Department of Internal Medicine III, Medical University of Vienna, Austria
| | - Michael Trauner
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology & Hepatology, Department of Internal Medicine III, Medical University of Vienna, Austria
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Sookoian S, Pirola CJ. Genetic predisposition in nonalcoholic fatty liver disease. Clin Mol Hepatol 2017; 23:1-12. [PMID: 28268262 PMCID: PMC5381829 DOI: 10.3350/cmh.2016.0109] [Citation(s) in RCA: 167] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 11/04/2016] [Indexed: 12/12/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease whose prevalence has reached global epidemic proportions. Although the disease is relatively benign in the early stages, when severe clinical forms, including nonalcoholic steatohepatitis (NASH), cirrhosis and even hepatocellular carcinoma, occur, they result in worsening the long-term prognosis. A growing body of evidence indicates that NAFLD develops from a complex process in which many factors, including genetic susceptibility and environmental insults, are involved. In this review, we focused on the genetic component of NAFLD, with special emphasis on the role of genetics in the disease pathogenesis and natural history. Insights into the topic of the genetic susceptibility in lean individuals with NAFLD and the potential use of genetic tests in identifying individuals at risk are also discussed.
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Affiliation(s)
- Silvia Sookoian
- Department of Clinical and Molecular Hepatology, Institute of Medical Research A Lanari-IDIM, University of Buenos Aires - National Scientific and Technical Research Council (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Carlos J Pirola
- Department of Molecular Genetics and Biology of Complex Diseases, Institute of Medical Research A Lanari-IDIM, University of Buenos Aires - National Scientific and Technical Research Council (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
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12
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Herta T, Fischer J, Berg T. Genetik metabolischer und viraler Lebererkrankungen. DER GASTROENTEROLOGE 2017; 12:16-31. [DOI: 10.1007/s11377-016-0128-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2025]
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13
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Lonardo A, Sookoian S, Pirola CJ, Targher G. Non-alcoholic fatty liver disease and risk of cardiovascular disease. Metabolism 2016; 65:1136-1150. [PMID: 26477269 DOI: 10.1016/j.metabol.2015.09.017] [Citation(s) in RCA: 175] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 08/17/2015] [Accepted: 09/19/2015] [Indexed: 02/06/2023]
Abstract
Non-alcoholic fatty liver disease (NAFLD) has become the leading cause of chronic liver diseases worldwide, causing considerable liver-related mortality and morbidity. During the past decade, it has also become increasingly evident that NAFLD is a multisystem disease that affects many extra-hepatic organ systems, including the heart and the vascular system. In this updated clinical review, we discuss the rapidly expanding body of clinical and epidemiological evidence that supports a strong association of NAFLD with cardiovascular diseases (CVDs) and other functional and structural myocardial abnormalities. We also discuss some recently published data that correlate NAFLD due to specific genetic polymorphisms with the risk of CVDs. Finally, we briefly examine the assessment tools for estimating the global CVD risk in patients with NAFLD as well as the conventional and the more innovative pharmacological approaches for the treatment of CVD risk in this group of patients.
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Affiliation(s)
- Amedeo Lonardo
- Outpatient Liver Clinic and Division of Internal Medicine, Department of Biomedical, Metabolic and Neural Sciences, NOCSAE, Baggiovara, Azienda USL and University of Modena and Reggio Emilia, Modena, Italy
| | - Silvia Sookoian
- Department of Clinical and Molecular Hepatology, Institute of Medical Research A Lanari-IDIM, University of Buenos Aires-National Scientific and Technical Research Council (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Carlos J Pirola
- Department of Molecular Genetics and Biology of Complex Diseases, Institute of Medical Research A Lanari-IDIM, University of Buenos Aires-National Scientific and Technical Research Council (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Giovanni Targher
- Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, University and Azienda Ospedaliera Universitaria Integrata of Verona, Verona, Italy.
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14
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Song G, Xiao C, Wang K, Wang Y, Chen J, Yu Y, Wang Z, Deng G, Sun X, Zhong L, Zhou C, Qi X, Wang S, Peng Z, Wang X. Association of patatin-like phospholipase domain-containing protein 3 gene polymorphisms with susceptibility of nonalcoholic fatty liver disease in a Han Chinese population. Medicine (Baltimore) 2016; 95:e4569. [PMID: 27537584 PMCID: PMC5370810 DOI: 10.1097/md.0000000000004569] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Gene polymorphisms had been found to be associated with increased risk of nonalcoholic fatty liver disease (NAFLD). The aim of the present study was to assess the association between rs2896019 and rs3810622 in PNPLA3 with the susceptibility to NAFLD in Han Chinese population.A total of 384 NAFLD patients and 384 controls were enrolled in the study. Blood samples collected from each subject were used for biochemical index analysis and DNA extraction. Genotyping analyses of PNPLA3 rs2896019 and rs3810622 were performed by real-time PCR methods.Results showed that patients with genotype GG of rs2896019 had a higher incidence of NAFLD than patients with genotypes GT and TT (62.4% vs 52.0% and 43.3%, respectively, P = 0.002), and a higher risk of moderate to severe NAFLD than patients with genotypes GT and TT (60.3% vs 46.2% and 40.2%, respectively, P = 0.03). Furthermore, patients with genotype GG of rs2896019 had higher levels of low-density lipoprotein (LDL, P < 0.001), ALT (P = 0.003), and AST (P = 0.002). Patients with genotype TT of rs3810622 had a higher incidence of NAFLD than patients with genotypes CT and CC (56.7% vs 48.4% and 41.5%, respectively, P = 0.013). Likewise, patients with genotype TT of rs3810622 had higher levels of ALT (P = 0.021) and blood glucose (GLU) (P = 0.034). Haplotype association analysis showed that GT haplotype conferred a statistically significant increased risk for NAFLD (OR = 1.49; 95% CI = 1.20-1.84, P < 0.01).These results suggest that PNPLA3 rs2896019 and rs3810622 polymorphisms significantly contribute to increased NAFLD risk in Han Chinese population.
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Affiliation(s)
- Guohe Song
- Department of General Surgery, Shanghai First People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai
| | - Chao Xiao
- Department of General Surgery, Shanghai First People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai
| | - Kai Wang
- Department of General Surgery, Children's Hospital of Zhengzhou, Henan, P. R. China
| | - Yupeng Wang
- Department of General Surgery, Shanghai First People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai
| | - Jian Chen
- Department of General Surgery, Shanghai First People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai
| | - Yang Yu
- Department of General Surgery, Shanghai First People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai
| | - Zhaowen Wang
- Department of General Surgery, Shanghai First People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai
| | - Guilong Deng
- Department of General Surgery, Shanghai First People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai
| | - Xing Sun
- Department of General Surgery, Shanghai First People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai
| | - Lin Zhong
- Department of General Surgery, Shanghai First People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai
| | - Chongzhi Zhou
- Department of General Surgery, Shanghai First People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai
| | - Xiaosheng Qi
- Department of General Surgery, Shanghai First People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai
| | - Shuyun Wang
- Department of General Surgery, Shanghai First People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai
| | - Zhihai Peng
- Department of General Surgery, Shanghai First People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai
| | - Xiaoliang Wang
- Department of General Surgery, Shanghai First People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai
- Correspondence: Xiaoliang Wang, Department of General Surgery, Shanghai First People's Hospital, School of Medicine, Shanghai Jiao Tong University, No.100, Haining Road, Shanghai 200080, P. R. China (e-mail: )
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15
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Macaluso FS, Maida M, Petta S. Genetic background in nonalcoholic fatty liver disease: A comprehensive review. World J Gastroenterol 2015; 21:11088-11111. [PMID: 26494964 PMCID: PMC4607907 DOI: 10.3748/wjg.v21.i39.11088] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 06/11/2015] [Accepted: 09/02/2015] [Indexed: 02/06/2023] Open
Abstract
In the Western world, nonalcoholic fatty liver disease (NAFLD) is considered as one of the most significant liver diseases of the twenty-first century. Its development is certainly driven by environmental factors, but it is also regulated by genetic background. The role of heritability has been widely demonstrated by several epidemiological, familial, and twin studies and case series, and likely reflects the wide inter-individual and inter-ethnic genetic variability in systemic metabolism and wound healing response processes. Consistent with this idea, genome-wide association studies have clearly identified Patatin-like phosholipase domain-containing 3 gene variant I148M as a major player in the development and progression of NAFLD. More recently, the transmembrane 6 superfamily member 2 E167K variant emerged as a relevant contributor in both NAFLD pathogenesis and cardiovascular outcomes. Furthermore, numerous case-control studies have been performed to elucidate the potential role of candidate genes in the pathogenesis and progression of fatty liver, although findings are sometimes contradictory. Accordingly, we performed a comprehensive literature search and review on the role of genetics in NAFLD. We emphasize the strengths and weaknesses of the available literature and outline the putative role of each genetic variant in influencing susceptibility and/or progression of the disease.
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Liang H, Xu J, Xu F, Liu H, Yuan D, Yuan S, Cai M, Yan J, Weng J. The SRE Motif in the Human PNPLA3 Promoter (-97 to -88 bp) Mediates Transactivational Effects of SREBP-1c. J Cell Physiol 2015; 230:2224-32. [PMID: 25655569 DOI: 10.1002/jcp.24951] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 01/23/2015] [Indexed: 12/24/2022]
Abstract
Patatin-like phospholipase domain containing 3 (PNPLA3) is a non-secreted protein primarily expressed in liver and adipose tissue. Recently, numerous genetic studies have shown that PNPLA3 is a major susceptibility gene for nonalcoholic fatty liver disease (NAFLD). However, the mechanism involved in transcriptional regulation of the PNPLA3 gene remains unknown. We performed a detailed analysis of the human PNPLA3 gene promoter and identified two novel cis-acting elements (SRE and NFY binding motifs) located at -97/-88 and -26/-22 bp, respectively. Overexpression of SREBP-1c in HepG2 cells significantly increased PNPLA3 promoter activity. Mutation of either of the putative SRE or NFY binding motifs blocked the transactivation effects of SREBP-1c on the promoter. Overexpression of SREBP-1c and NFY together increased PNPLA3 promoter activity twice as much as that of SREBP-1c or NFY expression alone. This result suggests that SREBP-1c and NFY synergistically transactivate the human PNPLA3 gene. The ability of SREBP-1c and NFY to bind these cis-elements was confirmed using gel shift analysis. Putative SRE and NFY motifs also mediated synergistic insulin-induced transactivation of the PNPLA3 promoter in HepG2 cells. Additionally, the ability of SREBP-1c to bind to the PNPLA3 promoter was increased by insulin in a dose-dependent manner. Moreover, the treatment of HepG2 cells with the PI3K inhibitor LY294002 led to reduced insulin promoter-activating ability accompanied by a decrease in PNPLA3 and SREBP-1c protein expression. These results demonstrate that SREBP-1c is a direct activator of the human PNPLA3 gene and insulin transactivates the PNPLA3 gene via the PI3K-SREBP-1c/NFY pathway in HepG2 cells.
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Affiliation(s)
- Hua Liang
- Department of Endocrinology and Metabolism, the Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, P.R.China
| | - Jing Xu
- Department of Endocrinology and Metabolism, the Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, P.R.China
| | - Fen Xu
- Department of Endocrinology and Metabolism, the Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, P.R.China
| | - Hongxia Liu
- Department of Endocrinology and Metabolism, the Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, P.R.China
| | - Ding Yuan
- Department of Endocrinology and Metabolism, the Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, P.R.China
| | - Shuhua Yuan
- Department of Endocrinology and Metabolism, the Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, P.R.China
| | - Mengyin Cai
- Department of Endocrinology and Metabolism, the Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, P.R.China
| | - Jinhua Yan
- Department of Endocrinology and Metabolism, the Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, P.R.China
| | - Jianping Weng
- Department of Endocrinology and Metabolism, the Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, P.R.China
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17
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Chen LZ, Xin YN, Geng N, Jiang M, Zhang DD, Xuan SY. PNPLA3 I148M variant in nonalcoholic fatty liver disease: Demographic and ethnic characteristics and the role of the variant in nonalcoholic fatty liver fibrosis. World J Gastroenterol 2015; 21:794-802. [PMID: 25624712 PMCID: PMC4299331 DOI: 10.3748/wjg.v21.i3.794] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 09/25/2014] [Accepted: 10/21/2014] [Indexed: 02/06/2023] Open
Abstract
Patatin-like phospholipase domain-containing 3 (PNPLA3 or adiponutrin) displays anabolic and catabolic activities in lipid metabolism, and has been reported to be significantly associated with liver fat content. Various studies have established a strong link between the 148 isoleucine to methionine protein variant (I148M) of PNPLA3 and liver diseases, including nonalcoholic fatty liver disease (NAFLD). However, detailed demographic and ethnic characteristics of the I148M variant and its role in the development of nonalcoholic fatty liver fibrosis have not been fully elucidated. The present review summarizes the current knowledge on the association between the PNPLA3 I148M variant and NAFLD, and especially its role in the development of nonalcoholic fatty liver fibrosis. First, we analyze the impact of demographic and ethnic characteristics of the PNPLA3 I148M variant and the presence of metabolic syndrome on the association between PNPLA3 I148M and NAFLD. Then, we explore the role of the PNPLA3 I148M in the development of nonalcoholic fatty liver fibrosis, and hypothesize the underlying mechanisms by speculating a pro-fibrogenic network. Finally, we briefly highlight future research that may elucidate the specific mechanisms of the PNPLA3 I148M variant in fibrogenesis, which, in turn, provides a theoretical foundation and valuable experimental data for the clinical management of nonalcoholic fatty liver fibrosis.
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18
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Association between the PNPLA3 I148M polymorphism and non-alcoholic fatty liver disease in the Uygur and Han ethnic groups of northwestern China. PLoS One 2014; 9:e108381. [PMID: 25290313 PMCID: PMC4188522 DOI: 10.1371/journal.pone.0108381] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 08/20/2014] [Indexed: 01/01/2023] Open
Abstract
Objective Multiple common gene variants play a role in non-alcoholic fatty liver disease (NAFLD) susceptibility. Our goal was to investigate the association between variants polymorphisms and NAFLD in the Uygur and Han from Northwestern China. Methods Eight tag single nucleotide polymorphisms (tSNPs) previously reported to be associated with NAFLD were characterized in 396 NAFLD individuals and 399 controls. The association of variants with NAFLD in the Uygur and Han was assessed using the chi-squared (χ2) test in different gene models. Unconditional logistic regression analysis was performed to obtain the odds ratios (ORs) for risk of NAFLD and their 95% confidence intervals (CI), adjusted for confounding factors. Finally, stratified analysis was used to explore the potential gene-environment interactions on the risk of NAFLD. Results In a recessive model, we found a potential association between rs738409 and NAFLD in both ethnic groups: Chinese Han (OR = 1.84, 95% CI: 1.03–3.27, p = 0.036), Uygur (OR = 2.25, 95% CI: 1.23–4.09, p = 0.006). The multiple logistic regression revealed that PNPLA3 rs738409 GG genotype may increase the risk of NAFLD by adjusting some confounding factors: Han (OR = 5.22, 95% CI: 1.94–14.04, p = 0.001), Uygur (OR = 4.29, 95% CI: 1.60–11.48, p = 0.004). Stratified analysis found that rs738409 polymorphism appeared to have interaction with sex, smoking status in Uygur, and have interaction with sex, age, BMI stage, lifestyle in Han. Conclusion Our data suggest the PNPLA3 I148M polymorphism influences susceptibility to NAFLD in the Han and Uygur of Northwestern China.
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19
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Hao L, Ito K, Huang KH, Sae-tan S, Lambert JD, Ross AC. Shifts in dietary carbohydrate-lipid exposure regulate expression of the non-alcoholic fatty liver disease-associated gene PNPLA3/adiponutrin in mouse liver and HepG2 human liver cells. Metabolism 2014; 63:1352-62. [PMID: 25060692 PMCID: PMC4175036 DOI: 10.1016/j.metabol.2014.06.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 05/24/2014] [Accepted: 06/17/2014] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Patatin-like phospholipase domain containing 3 (PNPLA3, adiponutrin) has been identified as a modifier of lipid metabolism. To better understand the physiological role of PNPLA3/adiponutrin, we have investigated its regulation in intact mice and human hepatocytes under various nutritional/metabolic conditions. MATERIAL/METHODS PNPLA3 gene expression was determined by real-time PCR in liver of C57BL/6 mice after dietary treatments and in HepG2 cells exposed to various nutritional/metabolic stimuli. Intracellular lipid content was determined in HepG2 cells after siRNA-mediated knockdown of PNPLA3. RESULTS In vivo, mice fed a high-carbohydrate (HC) liquid diet had elevated hepatic lipid content, and PNPLA3 mRNA and protein expression, compared to chow-fed mice. Elevated expression was completely abrogated by addition of unsaturated lipid emulsion to the HC diet. By contrast, in mice with high-fat diet-induced steatosis, Pnpla3 expression did not differ compared to low-fat fed mice. In HepG2 cells, Pnpla3 expression was reversibly suppressed by glucose depletion and increased by glucose refeeding, but unchanged by addition of insulin and glucagon. Several unsaturated fatty acids each significantly decreased Pnpla3 mRNA, similar to lipid emulsion in vivo. However, Pnpla3 knockdown in HepG2 cells did not alter total lipid content in high glucose- or oleic acid-treated cells. CONCLUSIONS Our results provide evidence that PNPLA3 expression is an early signal/signature of carbohydrate-induced lipogenesis, but its expression is not associated with steatosis per se. Under lipogenic conditions due to high-carbohydrate feeding, certain unsaturated fatty acids can effectively suppress both lipogenesis and PNPLA3 expression, both in vivo and in a hepatocyte cell line.
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Affiliation(s)
- Lei Hao
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA 16802 USA
| | - Kyoko Ito
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA 16802 USA
| | - Kuan-Hsun Huang
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA 16802 USA
| | - Sudathip Sae-tan
- Department of Food Science, The Pennsylvania State University, University Park, PA 16802 USA
| | - Joshua D Lambert
- Department of Food Science, The Pennsylvania State University, University Park, PA 16802 USA
| | - A Catharine Ross
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA 16802 USA; Center for Immunology and Infectious Disease, The Pennsylvania State University, University Park, PA 16802 USA.
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20
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Min HK, Sookoian S, Pirola CJ, Cheng J, Mirshahi F, Sanyal AJ. Metabolic profiling reveals that PNPLA3 induces widespread effects on metabolism beyond triacylglycerol remodeling in Huh-7 hepatoma cells. Am J Physiol Gastrointest Liver Physiol 2014; 307:G66-76. [PMID: 24763554 PMCID: PMC4080161 DOI: 10.1152/ajpgi.00335.2013] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 04/17/2014] [Indexed: 01/31/2023]
Abstract
PNPLA3 was recently associated with the susceptibility to nonalcoholic fatty liver disease, a common cause of chronic liver disease characterized by abnormal triglyceride accumulation. Although it is established that PNPLA3 has both triacylglycerol lipase and acylglycerol O-acyltransferase activities, is still unknown whether the gene has any additional role in the modulation of the human liver metabolome. To uncover the functional role of PNPLA3 on liver metabolism, we performed high-throughput metabolic profiling of PNPLA3 siRNA-silencing and overexpression of wild-type and mutant Ile148Met variants (isoleucine/methionine substitution at codon 148) in Huh-7 cells. Metabolomic analysis was performed by using GC/MS and LC/MS platforms. Silencing of PNPLA3 was associated with a global perturbation of Huh-7 hepatoma cells that resembled a catabolic response associated with protein breakdown. A significant decrease in amino- and γ-glutamyl-amino acids and dipeptides and a significant increase in cysteine sulfinic acid, myo-inositol, lysolipids, sphingolipids, and polyunsaturated fatty acids were observed. Overexpression of the PNPLA3 Met148 variant mirrored many of the metabolic changes observed during gene silencing, but in the opposite direction. These findings were replicated by the exploration of canonical pathways associated with PNPLA3 silencing and Met148 overexpression. Overexpression of the PNPLA3 Met148 variant was associated with a 1.75-fold increase in lactic acid, suggesting a shift to anaerobic metabolism and mitochondrial dysfunction. Together, these results suggest a critical role of PNPLA3 in the modulation of liver metabolism beyond its classical participation in triacylglycerol remodeling.
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Affiliation(s)
- Hae-Ki Min
- Division of Gastroenterology, Hepatology and Nutrition, Department of Internal Medicine, Virginia Commonwealth University School of Medicine, Richmond, Virginia; and
| | - Silvia Sookoian
- Department of Clinical and Molecular Hepatology and Molecular Genetics and Biology of Complex Diseases, Institute of Medical Research, IDIM, University of Buenos Aires-National Scientific and Technical Research Council (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Carlos J Pirola
- Department of Clinical and Molecular Hepatology and Molecular Genetics and Biology of Complex Diseases, Institute of Medical Research, IDIM, University of Buenos Aires-National Scientific and Technical Research Council (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Jianfeng Cheng
- Division of Gastroenterology, Hepatology and Nutrition, Department of Internal Medicine, Virginia Commonwealth University School of Medicine, Richmond, Virginia; and
| | - Faridoddin Mirshahi
- Division of Gastroenterology, Hepatology and Nutrition, Department of Internal Medicine, Virginia Commonwealth University School of Medicine, Richmond, Virginia; and
| | - Arun J Sanyal
- Division of Gastroenterology, Hepatology and Nutrition, Department of Internal Medicine, Virginia Commonwealth University School of Medicine, Richmond, Virginia; and
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Ruhanen H, Perttilä J, Hölttä-Vuori M, Zhou Y, Yki-Järvinen H, Ikonen E, Käkelä R, Olkkonen VM. PNPLA3 mediates hepatocyte triacylglycerol remodeling. J Lipid Res 2014; 55:739-46. [PMID: 24511104 DOI: 10.1194/jlr.m046607] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The I148M substitution in patatin-like phospholipase domain containing 3 (PNPLA3(I148M)) determines a genetic form of nonalcoholic fatty liver disease. To elucidate the mode of PNPLA3 action in human hepatocytes, we studied effects of WT PNPLA3 (PNPLA3(WT)) and PNPLA3(I148M) on HuH7 cell lipidome after [(13)C]glycerol labeling, cellular turnover of oleic acid labeled with 17 deuterium atoms ([D17]oleic acid) in triacylglycerols (TAGs), and subcellular distribution of the protein variants. PNPLA3(I148M) induced a net accumulation of unlabeled TAGs, but not newly synthesized total [(13)C]TAGs. Principal component analysis (PCA) revealed that both PNPLA3(WT) and PNPLA3(I148M) induced a relative enrichment of TAGs with saturated FAs or MUFAs, with concurrent enrichment of polyunsaturated phosphatidylcholines. PNPLA3(WT) associated in PCA with newly synthesized [(13)C]TAGs, particularly 52:1 and 50:1, while PNPLA3(I148M) associated with similar preexisting TAGs. PNPLA3(WT) overexpression resulted in increased [D17]oleic acid labeling of TAGs during 24 h, and after longer incubations their turnover was accelerated, effects not detected with PNPLA3(I148M). PNPLA3(I148M) localized more extensively to lipid droplets (LDs) than PNPLA3(WT), suggesting that the substitution alters distribution of PNPLA3 between LDs and endoplasmic reticulum/cytosol. This study reveals a function of PNPLA3 in FA-selective TAG remodeling, resulting in increased TAG saturation. A defect in TAG remodeling activity likely contributes to the TAG accumulation observed in cells expressing PNPLA3(I148M).
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Affiliation(s)
- Hanna Ruhanen
- Minerva Foundation Institute for Medical Research, Biomedicum 2U, FI-00290 Helsinki, Finland
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22
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Kumashiro N, Yoshimura T, Cantley JL, Majumdar SK, Guebre-Egziabher F, Kursawe R, Vatner DF, Fat I, Kahn M, Erion DM, Zhang XM, Zhang D, Manchem VP, Bhanot S, Gerhard GS, Petersen KF, Cline GW, Samuel VT, Shulman GI. Role of patatin-like phospholipase domain-containing 3 on lipid-induced hepatic steatosis and insulin resistance in rats. Hepatology 2013; 57:1763-72. [PMID: 23175050 PMCID: PMC3597437 DOI: 10.1002/hep.26170] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 11/07/2012] [Indexed: 12/13/2022]
Abstract
UNLABELLED Genome-wide array studies have associated the patatin-like phospholipase domain-containing 3 (PNPLA3) gene polymorphisms with hepatic steatosis. However, it is unclear whether PNPLA3 functions as a lipase or a lipogenic enzyme and whether PNPLA3 is involved in the pathogenesis of hepatic insulin resistance. To address these questions we treated high-fat-fed rats with specific antisense oligonucleotides to decrease hepatic and adipose pnpla3 expression. Reducing pnpla3 expression prevented hepatic steatosis, which could be attributed to decreased fatty acid esterification measured by the incorporation of [U-(13) C]-palmitate into hepatic triglyceride. While the precursors for phosphatidic acid (PA) (long-chain fatty acyl-CoAs and lysophosphatidic acid [LPA]) were not decreased, we did observe an ∼20% reduction in the hepatic PA content, ∼35% reduction in the PA/LPA ratio, and ∼60%-70% reduction in transacylation activity at the level of acyl-CoA:1-acylglycerol-sn-3-phosphate acyltransferase. These changes were associated with an ∼50% reduction in hepatic diacylglycerol (DAG) content, an ∼80% reduction in hepatic protein kinase Cε activation, and increased hepatic insulin sensitivity, as reflected by a 2-fold greater suppression of endogenous glucose production during the hyperinsulinemic-euglycemic clamp. Finally, in humans, hepatic PNPLA3 messenger RNA (mRNA) expression was strongly correlated with hepatic triglyceride and DAG content, supporting a potential lipogenic role of PNPLA3 in humans. CONCLUSION PNPLA3 may function primarily in a lipogenic capacity and inhibition of PNPLA3 may be a novel therapeutic approach for treatment of nonalcoholic fatty liver disease-associated hepatic insulin resistance.
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Affiliation(s)
- Naoki Kumashiro
- Howard Hughes Medical Institute, Yale University, School of MedicineNew Haven, CT,Department of Internal Medicine, Yale University School of MedicineNew Haven, CT
| | - Toru Yoshimura
- Department of Internal Medicine, Yale University School of MedicineNew Haven, CT
| | - Jennifer L Cantley
- Howard Hughes Medical Institute, Yale University, School of MedicineNew Haven, CT,Department of Internal Medicine, Yale University School of MedicineNew Haven, CT
| | - Sachin K Majumdar
- Department of Internal Medicine, Yale University School of MedicineNew Haven, CT
| | | | - Romy Kursawe
- Department of Pediatrics, Yale University School of MedicineNew Haven, CT
| | - Daniel F Vatner
- Department of Internal Medicine, Yale University School of MedicineNew Haven, CT
| | - Ioana Fat
- Department of Internal Medicine, Yale University School of MedicineNew Haven, CT
| | - Mario Kahn
- Department of Internal Medicine, Yale University School of MedicineNew Haven, CT
| | - Derek M Erion
- Howard Hughes Medical Institute, Yale University, School of MedicineNew Haven, CT,Department of Internal Medicine, Yale University School of MedicineNew Haven, CT,Department of Cellular & Molecular Physiology, Yale University School of MedicineNew Haven, CT
| | - Xian-Man Zhang
- Howard Hughes Medical Institute, Yale University, School of MedicineNew Haven, CT,Department of Internal Medicine, Yale University School of MedicineNew Haven, CT
| | - Dongyan Zhang
- Howard Hughes Medical Institute, Yale University, School of MedicineNew Haven, CT,Department of Internal Medicine, Yale University School of MedicineNew Haven, CT,Department of Cellular & Molecular Physiology, Yale University School of MedicineNew Haven, CT
| | | | | | | | - Kitt F Petersen
- Department of Internal Medicine, Yale University School of MedicineNew Haven, CT
| | - Gary W Cline
- Department of Internal Medicine, Yale University School of MedicineNew Haven, CT
| | - Varman T Samuel
- Department of Internal Medicine, Yale University School of MedicineNew Haven, CT,Veterans Affairs Medical CenterWest Haven CT
| | - Gerald I Shulman
- Howard Hughes Medical Institute, Yale University, School of MedicineNew Haven, CT,Department of Internal Medicine, Yale University School of MedicineNew Haven, CT,Department of Cellular & Molecular Physiology, Yale University School of MedicineNew Haven, CT,Correspondence to: Gerald I. Shulman, Howard Hughes Medical Institute, Yale University, Department of Internal Medicine, Yale University School of Medicine, P.O. Box 9812, New Haven, CT, 06536-8012. ; fax: 203-737-4059
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23
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Chamoun Z, Vacca F, Parton RG, Gruenberg J. PNPLA3/adiponutrin functions in lipid droplet formation. Biol Cell 2013; 105:219-233. [PMID: 23398201 DOI: 10.1111/boc.201200036] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Accepted: 02/04/2013] [Indexed: 01/04/2023]
Abstract
BACKGROUND INFORMATION In animals, adipose tissue contains the main energy store as lipid droplets (LDs) composed of esterified cholesterol (CE) and triacylglycerol (TAG) enveloped in a mono-layer of phospholipid and decorated by a coat of proteins. Upon increased energy demand, dedicated lipases hydrolyse TAG stepwise into free fatty acids that are released in circulation and made available to peripheral tissue. In case of aberrant caloric load, TAGs are deposited into non-adipocyte tissues, primarily liver cells. For instance, non-alcoholic fatty liver disease (NAFLD) is a common chronic disorder characterised by an excess of TAG in the liver of patients regardless of their susceptibility to obesity, diabetes or exposure to alcohol. Several independent linkage studies have associated NAFLD with a non-synonymous variant of patatin-like phospholipase domain-containing 3 (PNPLA3/adiponutrin) encoding an isoleucine to methionine substitution at position 148 (I148M) (see Cohen et al., 2011 for review). However, the mechanism by which a variation in PNPLA3 gives susceptibility to NAFLD is not known, primarily because the physiological role of PNPLA3 still needs to be elucidated. RESULTS We have identified PNPLA3 in a screen for genes upregulated by intracellular lipid accumulation. We investigated the sub-cellular distribution and potential function of PNPLA3 in fibroblast-like cells supplemented with lipids. We demonstrate that PNPLA3 is targetted to LDs in a process that requires an intact Brummer box domain, which is conserved in the patatin-like phospholipase family. We show that increased levels of the NAFLD-linked PNPLA3 isoform leads to larger LDs, whereas decreased levels of PNPLA3 had the opposite effect. Interestingly, however, PNPLA3 induced a reduction in LD size upon co-expression with ABDH5/CGI-58, an activator of the TAG lipase PNPLA2, which is the closest homolog of PNPLA3. By investigating LD populations according to their size and composition, we show that perturbing intracellular lipid trafficking drastically modifies LD nature. CONCLUSIONS Taken together, our results suggest that PNPLA3 exhibits a dual function in LD metabolism, and that it participates in the restoration of lipid homeostasis upon aberrant intracellular lipid accumulation.
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Affiliation(s)
- Zeina Chamoun
- Department of Biochemistry, University of Geneva, Geneva 4, Switzerland
| | - Fabrizio Vacca
- Department of Biochemistry, University of Geneva, Geneva 4, Switzerland
| | - Robert G Parton
- The University of Queensland, Institute for Molecular Bioscience and Center for Microscopy and Microanalysis, Brisbane 4072, Australia
| | - Jean Gruenberg
- Department of Biochemistry, University of Geneva, Geneva 4, Switzerland
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Chen LJ, Wen XY, Niu JQ. Role of PNPLA3 polymorphism in pathogenesis of liver diseases. Shijie Huaren Xiaohua Zazhi 2013; 21:667-672. [DOI: 10.11569/wcjd.v21.i8.667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Hepatic fat accumulation, a common phenomenon in nonalcoholic fatty liver disease (NAFLD) and alcoholic liver disease (ALD), is associated with liver inflammation development and disease progression. Besides, hepatic fat accumulation is also seen in HCV-infected patients, which influences the response to anti-HCV therapy. Although the causes of fatty accumulation in the above three diseases are different, hereditary factors causing fatty accumulation have attracted more and more attention. PNPLA3, a member of patatin-like phospholipase family, has the activity of triglyceride hydrolase and can influence the liver fatty metabolism. In recent years, PNPLA3 polymorphism has become a hot topic in research of NAFLD, ALD, and HCV, and important results have been achieved. This article describes the expression of PNPLA3 in human tissues and review recent progress in understanding the role of PNPLA3 polymorphism in the pathogenesis of the above three liver diseases.
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Sookoian S, Pirola CJ. PNPLA3, the triacylglycerol synthesis/hydrolysis/storage dilemma, and nonalcoholic fatty liver disease. World J Gastroenterol 2012; 18:6018-6026. [PMID: 23155331 PMCID: PMC3496879 DOI: 10.3748/wjg.v18.i42.6018] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 09/28/2012] [Indexed: 02/06/2023] Open
Abstract
Genome-wide and candidate gene association studies have identified several variants that predispose individuals to developing nonalcoholic fatty liver disease (NAFLD). However, the gene that has been consistently involved in the genetic susceptibility of NAFLD in humans is patatin-like phospholipase domain containing 3 (PNPLA3, also known as adiponutrin). A nonsynonymous single nucleotide polymorphism in PNPLA3 (rs738409 C/G, a coding variant that encodes an amino acid substitution I148M) is significantly associated with fatty liver and histological disease severity, not only in adults but also in children. Nevertheless, how PNPLA3 influences the biology of fatty liver disease is still an open question. A recent article describes new aspects about PNPLA3 gene/protein function and suggests that the I148M variant promotes hepatic lipid synthesis due to a gain of function. We revise here the published data about the role of the I148M variant in lipogenesis/lipolysis, and suggest putative areas of future research. For instance we explored in silico whether the rs738409 C or G alleles have the ability to modify miRNA binding sites and miRNA gene regulation, and we found that prediction of PNPLA3 target miRNAs shows two miRNAs potentially interacting in the 3’UTR region (hsa-miR-769-3p and hsa-miR-516a-3p). In addition, interesting unanswered questions remain to be explored. For example, PNPLA3 lies between two CCCTC-binding factor-bound sites that could be tested for insulator activity, and an intronic histone 3 lysine 4 trimethylation peak predicts an enhancer element, corroborated by the DNase I hypersensitivity site peak. Finally, an interaction between PNPLA3 and glycerol-3-phosphate acyltransferase 2 is suggested by data miming.
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Perttilä J, Huaman-Samanez C, Caron S, Tanhuanpää K, Staels B, Yki-Järvinen H, Olkkonen VM. PNPLA3 is regulated by glucose in human hepatocytes, and its I148M mutant slows down triglyceride hydrolysis. Am J Physiol Endocrinol Metab 2012; 302:E1063-9. [PMID: 22338072 DOI: 10.1152/ajpendo.00125.2011] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Liver fat is increased in carriers of the minor G allele in rs738409 (I148M amino acid substitution) in patatin-like phospholipase domain-containing 3 (PNPLA3)/adiponutrin. We studied transcriptional regulation of PNPLA3 in immortalized human hepatocytes (IHH) and human hepatoma cells (HuH7) and the impact of PNPLA3 I148M mutant on hepatocyte triglyceride metabolism. Studies in IHH showed that silencing of the carbohydrate response element-binding protein (ChREBP) abolished induction of PNPLA3 mRNA by glucose. Glucose-dependent binding of ChREBP to a newly identified carbohydrate response element in the PNPLA3 promoter was demonstrated by chromatin immunoprecipitation. Adenoviral overexpression of mouse ChREBP in IHH failed to induce PNPLA3 mRNA. [(3)H]acetate or [(3)H]oleate incorporation with 1-h pulse labeling or 18-h [(3)H]oleate labeling in HuH7 cells showed no effect of PNPLA3 I148M on triglyceride (TG) synthesis in the absence of free fatty acid (FFA) loading. Increased [(3)H]oleate accumulation into triglycerides in I148M-expressing cells was observed after 18 h of labeling in the presence of 200 μM FFA-albumin complexes. This was accompanied by increased PNPLA3 protein levels. The rate of hydrolysis of [(3)H]TG during lipid depletion was decreased significantly by PNPLA3 I148M. Our results suggest that PNPLA3 is regulated in human hepatocytes by glucose via ChREBP. PNPLA3 I148M enhances cellular accumulation of [(3)H]TG in the presence of excess FFA, which is known to stabilize PNPLA3 protein. These data do not exclude an effect of PNPLA3 I148M on hepatocyte lipogenesis but show that the mutant increases the stability of triglycerides.
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Affiliation(s)
- Julia Perttilä
- Minerva Foundation Institute for Medical Research, Helsinki, Finland.
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Kumari M, Schoiswohl G, Chitraju C, Paar M, Cornaciu I, Rangrez AY, Wongsiriroj N, Nagy HM, Ivanova PT, Scott SA, Knittelfelder O, Rechberger GN, Birner-Gruenberger R, Eder S, Brown HA, Haemmerle G, Oberer M, Lass A, Kershaw EE, Zimmermann R, Zechner R. Adiponutrin functions as a nutritionally regulated lysophosphatidic acid acyltransferase. Cell Metab 2012; 15:691-702. [PMID: 22560221 PMCID: PMC3361708 DOI: 10.1016/j.cmet.2012.04.008] [Citation(s) in RCA: 238] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 02/17/2012] [Accepted: 04/10/2012] [Indexed: 12/12/2022]
Abstract
Numerous studies in humans link a nonsynonymous genetic polymorphism (I148M) in adiponutrin (ADPN) to various forms of fatty liver disease and liver cirrhosis. Despite its high clinical relevance, the molecular function of ADPN and the mechanism by which I148M variant affects hepatic metabolism are unclear. Here we show that ADPN promotes cellular lipid synthesis by converting lysophosphatidic acid (LPA) into phosphatidic acid. The ADPN-catalyzed LPA acyltransferase (LPAAT) reaction is specific for LPA and long-chain acyl-CoAs. Wild-type mice receiving a high-sucrose diet exhibit substantial upregulation of Adpn in the liver and a concomitant increase in LPAAT activity. In Adpn-deficient mice, this diet-induced increase in hepatic LPAAT activity is reduced. Notably, the I148M variant of human ADPN exhibits increased LPAAT activity leading to increased cellular lipid accumulation. This gain of function provides a plausible biochemical mechanism for the development of liver steatosis in subjects carrying the I148M variant.
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Affiliation(s)
- Manju Kumari
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
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Abstract
Nonalcoholic fatty liver disease (NAFLD) has emerged as the most common cause of pediatric liver disease in the developed world. Children have a form of NAFLD that is pathologically distinct from adults. Although NAFLD remains a pathologic diagnosis, biomarkers and imaging studies hold promise as noninvasive means of both establishing the diagnosis and following the disease course. Significant advancements have recently been made in genetics, pathophysiology, and the treatment of NAFLD. The purpose of this article is to provide a clinically relevant review of pediatric NAFLD with an emphasis on recent developments in the field.
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Nischalke HD, Berger C, Luda C, Berg T, Müller T, Grünhage F, Lammert F, Coenen M, Krämer B, Körner C, Vidovic N, Oldenburg J, Nattermann J, Sauerbruch T, Spengler U. The PNPLA3 rs738409 148M/M genotype is a risk factor for liver cancer in alcoholic cirrhosis but shows no or weak association in hepatitis C cirrhosis. PLoS One 2011; 6:e27087. [PMID: 22087248 PMCID: PMC3210131 DOI: 10.1371/journal.pone.0027087] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 10/10/2011] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND An isoleucine>methionine mutation at position 148 in the PNPLA3 gene (p.I148M, rs738409) has recently been identified as a susceptibility factor for liver damage in steatohepatitis. Here, we studied whether the PNPLA3 rs738409 polymorphism also affects predisposition to hepatocellular carcinoma (HCC). METHODS We compared distributions of PNPLA3 genotypes in 80 and 81 Caucasian patients with alcoholic and hepatitis C virus (HCV)-associated HCC to 80 and 81 age- and sex-matched patients with alcohol-related and HCV-related cirrhosis without HCC, respectively. PNPLA3 genotypes in 190 healthy individuals from the same population served as reference. Potential confounders obesity, diabetes, HCV genotype and HBV co-infection were controlled by univariate and multivariate logistic regression with forward variable selection. RESULTS PNPLA3 genotypes were in Hardy-Weinberg equilibrium for all study groups. The frequency of the 148M allele was significantly (p<0.001) increased in alcoholic cirrhosis with (53.7%) and without HCC (36.2%) but was not different between healthy controls (22.9%) and patients with cirrhosis (25.3%; p = 0.545) and HCC (30.2%; p = 0.071) due to hepatitis C. HCC risk was highest in 148M/M homozygous patients with alcoholic liver disease (odds ratio (OR) 16.8 versus healthy controls; 95% confidence interval (CI) 6.68-42.43, p<0.001). Finally, multivariate regression confirmed 148M/M homozygosity (OR 2.8; 95%-CI: 1.24-6.42; p = 0.013) as HCC risk factor in alcoholic cirrhosis. In HCV-related cirrhosis only HCV genotype 1 was confirmed as a HCC risk factor (OR 4.2; 95%-CI: 1.50-11.52; p = 0.006). CONCLUSION The PNPLA3 148M variant is a prominent risk factor for HCC in patients with alcoholic cirrhosis, while its effects are negligible in patients with cirrhosis due to HCV. This polymorphism provides an useful tool to identify individuals with particularly high HCC risk in patients with alcoholic liver disease that should be taken into account in future HCC prevention studies.
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Affiliation(s)
| | - Cordula Berger
- Department of Internal Medicine I, University of Bonn, Bonn, Germany
| | - Carolin Luda
- Department of Internal Medicine I, University of Bonn, Bonn, Germany
| | - Thomas Berg
- Department of Gastroenterology, University Hospital Leipzig, Leipzig, Germany
| | - Tobias Müller
- Medical Clinic for Hepatology and Gastroenterology, Medical University Charité Campus, Virchow–Klinikum Berlin, Berlin, Germany
| | - Frank Grünhage
- Department of Internal Medicine II, Saarland University Hospital, Homburg, Germany
| | - Frank Lammert
- Department of Internal Medicine II, Saarland University Hospital, Homburg, Germany
| | - Martin Coenen
- Department of Internal Medicine I, University of Bonn, Bonn, Germany
| | - Benjamin Krämer
- Department of Internal Medicine I, University of Bonn, Bonn, Germany
| | - Christian Körner
- Department of Internal Medicine I, University of Bonn, Bonn, Germany
| | - Natascha Vidovic
- Institute for Experimental Hematology and Transfusion Medicine, University of Bonn, Bonn, Germany
| | - Johannes Oldenburg
- Institute for Experimental Hematology and Transfusion Medicine, University of Bonn, Bonn, Germany
| | - Jacob Nattermann
- Department of Internal Medicine I, University of Bonn, Bonn, Germany
| | - Tilman Sauerbruch
- Department of Internal Medicine I, University of Bonn, Bonn, Germany
| | - Ulrich Spengler
- Department of Internal Medicine I, University of Bonn, Bonn, Germany
- * E-mail:
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Li DY, Lin LJ, Zheng CQ. Advances in understanding the role of PNPLA3 in the pathogenesis of non-alcoholic fatty liver disease. Shijie Huaren Xiaohua Zazhi 2011; 19:1796-1801. [DOI: 10.11569/wcjd.v19.i17.1796] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The incidence of non-alcoholic fatty liver disease (NAFLD) is rising worldwide. Investigation of genes involved in the pathogenesis of NAFLD is significant for replenishing treatment scheme and improving prognosis. Multiple studies have established a correlation between patatin-like phospholipase domain-containing 3 (PNPLA3) gene mutation and the pathogenesis of NAFLD, suggesting that PNPLA3 may affect lipid metabolism. However, the precise mechanism remains to be elucidated. Some researchers believed that PNPLA3 as a patatin-like protein might have triglyceride hydrolysis activity and therefore affect fat metabolism in the liver, while some others thought that PNPLA3 mutation might interfere with the lipid transfer process. In this paper, we give an overview of the PNPLA3 gene and its expression, and explore the correlation between PNPLA3 gene mutation and the pathogenesis of NAFLD.
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