1
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Steigemann P, Braeuer N, Puetter V, Zablowsky N, Juenemann K, von Nussbaum F, Lesche R, Dittmar N, Schaller D, Makowska Z, Klironomos F, Schwarz S, Launhardt D, Bader B, Lange M, Steuber H, Black MH, Packer JS, Romeo S, Fasler S, Bedford L, Dewey FE. Identification of NUV-244 as a PNPLA3 I148M degrading small molecule. iScience 2025; 28:112384. [PMID: 40322074 PMCID: PMC12049818 DOI: 10.1016/j.isci.2025.112384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2024] [Revised: 12/05/2024] [Accepted: 04/04/2025] [Indexed: 05/08/2025] Open
Abstract
The PNPLA3 I148M variant is a key genetic determinant of metabolic dysfunction-associated steatotic liver disease (MASLD) and related conditions, contributing to lipid metabolism dysregulation and disease progression. To identify small molecules that modulate PNPLA3 I148M, we conducted a high-content screen of over 820,000 compounds and identified NUV-244, a potent degrader of PNPLA3 I148M in liver-derived cells. NUV-244 reduces PNPLA3 I148M levels on lipid droplets via the ubiquitin-proteasome system, involving the E3 ligase BFAR, without affecting PNPLA2. It restores lipid droplet morphology and improves cellular fitness in PNPLA3 I148M-expressing cells. These findings provide a tool to investigate PNPLA3 I148M function and offer a potential strategy for developing targeted therapies for MASLD and related diseases. By enabling selective degradation of PNPLA3 I148M, this approach expands therapeutic possibilities beyond genetic manipulation, addressing a critical need in metabolic liver disease research.
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Affiliation(s)
| | - Nico Braeuer
- Nuvisan ICB GmbH, Müllerstrasse 178, 13353 Berlin, Germany
| | - Vera Puetter
- Nuvisan ICB GmbH, Müllerstrasse 178, 13353 Berlin, Germany
| | - Nina Zablowsky
- Nuvisan ICB GmbH, Müllerstrasse 178, 13353 Berlin, Germany
| | | | | | - Ralf Lesche
- Nuvisan ICB GmbH, Müllerstrasse 178, 13353 Berlin, Germany
| | - Nicole Dittmar
- Nuvisan ICB GmbH, Müllerstrasse 178, 13353 Berlin, Germany
| | - David Schaller
- Nuvisan ICB GmbH, Müllerstrasse 178, 13353 Berlin, Germany
| | | | | | | | | | - Benjamin Bader
- Nuvisan ICB GmbH, Müllerstrasse 178, 13353 Berlin, Germany
| | - Martin Lange
- Nuvisan ICB GmbH, Müllerstrasse 178, 13353 Berlin, Germany
| | - Holger Steuber
- Nuvisan ICB GmbH, Müllerstrasse 178, 13353 Berlin, Germany
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2
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Norden-Krichmar TM, Rotroff D, Schwantes-An TH, Bataller R, Goldman D, Nagy LE, Liangpunsakul S. Genomic approaches to explore susceptibility and pathogenesis of alcohol use disorder and alcohol-associated liver disease. Hepatology 2025; 81:1595-1606. [PMID: 37796138 PMCID: PMC10985049 DOI: 10.1097/hep.0000000000000617] [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: 05/24/2023] [Accepted: 08/13/2023] [Indexed: 10/06/2023]
Abstract
Excessive alcohol use is a major risk factor for the development of an alcohol use disorder (AUD) and contributes to a wide variety of other medical illnesses, including alcohol-associated liver disease (ALD). Both AUD and ALD are complex and causally interrelated diseases, and multiple factors other than alcohol consumption are implicated in the disease pathogenesis. While the underlying pathophysiology of AUD and ALD is complex, there is substantial evidence for a genetic susceptibility of both diseases. Current genome-wide association studies indicate that the genes associated with clinical AUD only poorly overlap with the genes identified for heavy drinking and, in turn, neither overlap with the genes identified for ALD. Uncovering the main genetic factors will enable us to identify molecular drivers underlying the pathogenesis, discover potential targets for therapy, and implement patient care early in disease progression. In this review, we described multiple genomic approaches and their implications to investigate the susceptibility and pathogenesis of both AUD and ALD. We concluded our review with a discussion of the knowledge gaps and future research on genomic studies in these 2 diseases.
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Affiliation(s)
| | - Daniel Rotroff
- Department of Quantitative Health Sciences, Cleveland Clinic, Cleveland, OH
| | - Tae-Hwi Schwantes-An
- Department of Medical & Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN
| | - Ramon Bataller
- Liver Unit, Institut of Digestive and Metabolic Diseases, Hospital Clinic, Barcelona, Spain
- Institut d’Investigacions Biomediques August Pi i Sunyer (IDIBAPS)
| | - David Goldman
- Laboratory of Neurogenetics and Office of the Clinical Director, National Institute on Alcohol Abuse and Alcoholism, Rockville, MD
| | - Laura E. Nagy
- Center for Liver Disease Research, Department of Inflammation and Immunity, Cleveland Clinic, Cleveland, OH
- Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, OH
- Department of Molecular Medicine, Case Western Reserve University, Cleveland, OH
| | - Suthat Liangpunsakul
- Division of Gastroenterology and Hepatology, Department of Medicine, Indianapolis, IN
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN
- Roudebush Veterans Administration Medical Center, Indianapolis, IN
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3
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Ramandi A, Diehl AM, Sanyal AJ, de Jong YP. Experimental Models to Investigate PNPLA3 in Liver Steatosis. Liver Int 2025; 45:e70091. [PMID: 40231787 DOI: 10.1111/liv.70091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2025] [Revised: 03/26/2025] [Accepted: 03/30/2025] [Indexed: 04/16/2025]
Abstract
Patatin-like phospholipase domain-containing 3 (PNPLA3) was the first gene identified through genome-wide association studies to be linked to hepatic fat accumulation. A missense variant, encoding the PNPLA3-148M allele, has since been shown to increase the risk for the full spectrum of steatotic liver disease (SLD), from simple steatosis to steatohepatitis, cirrhosis, and hepatocellular carcinoma. Despite extensive validation of this association and ongoing research into its pathogenic role, the precise mechanisms by which PNPLA3-148M contributes to the progression of SLD remain poorly understood. In this review, we evaluate preclinical in vitro and in vivo models used to investigate PNPLA3 and its involvement in SLD, with particular emphasis on metabolic dysfunction-associated steatotic liver disease. We assess the strengths and limitations of these models, as well as the challenges arising from species differences in PNPLA3 expression and function between human and murine systems.
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Affiliation(s)
- Alireza Ramandi
- Division of Gastroenterology and Hepatology, Weill Cornell Medicine, New York, New York, USA
| | - Anna-Mae Diehl
- Department of Medicine, Duke University, Durham, North Carolina, USA
| | - Arun J Sanyal
- Stravitz-Sanyal Institute for Liver Disease and Metabolic Health, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Ype P de Jong
- Division of Gastroenterology and Hepatology, Weill Cornell Medicine, New York, New York, USA
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4
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Uchinuma H, Matsushita M, Tanahashi M, Suganami H, Utsunomiya K, Kaku K, Tsuchiya K. Post-hoc analysis of the tofogliflozin post-marketing surveillance study (J-STEP/LT): Tofogliflozin improves liver function in type 2 diabetes patients regardless of BMI. J Diabetes Investig 2025; 16:615-628. [PMID: 39823131 PMCID: PMC11970296 DOI: 10.1111/jdi.14402] [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: 08/25/2024] [Revised: 12/05/2024] [Accepted: 12/27/2024] [Indexed: 01/19/2025] Open
Abstract
AIMS/INTRODUCTION Patients with type 2 diabetes are at high risk of developing steatotic liver disease (SLD). Weight loss has proven effective in treating metabolic dysfunction-associated steatotic liver disease (MASLD) in obese patients with type 2 diabetes, with sodium-glucose cotransporter 2 (SGLT2) inhibitors showing promising results. However, lean MASLD is more prevalent in Japan, necessitating alternative approaches to body weight reduction. MATERIALS AND METHODS We used the J-STEP/LT dataset including up to 3-year treatment data to analyze the effects of the SGLT2 inhibitor tofogliflozin on liver function and treatment safety and conducted a subgroup analysis based on body mass index (BMI; kg/m2, <20, 20-<23, 23-<25, 25-<30, and ≥30). RESULTS This study included 4,208 participants. Tofogliflozin significantly reduced alanine aminotransferase (ALT) levels in participants with baseline ALT levels >30 U/L across all BMI groups, with median changes of -12, -16, -13, -15, and -15 U/L, respectively (P = 0.9291 for trends). However, median changes in body weight with tofogliflozin were -2.00, -2.75, -2.00, -3.00, and -3.80 kg, respectively (P < 0.0001 for trends), with no significant weight loss observed in the BMI <20 group. ALT levels were also significantly decreased in participants who did not lose weight. Safety assessments according to BMI and age categories revealed no clear differences in the frequency of adverse events. CONCLUSIONS Tofogliflozin reduced ALT levels without substantial body weight reduction among lean participants. These findings suggest that SGLT2 inhibitors may be a viable treatment option for non-obese patients with type 2 diabetes and SLD.
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Affiliation(s)
- Hiroyuki Uchinuma
- Department of Diabetes and EndocrinologyUniversity of Yamanashi HospitalYamanashiJapan
| | | | | | | | | | - Kohei Kaku
- Division of Diabetes, Metabolism and EndocrinologyKawasaki Medical SchoolOkayamaJapan
| | - Kyoichiro Tsuchiya
- Department of Diabetes and EndocrinologyUniversity of Yamanashi HospitalYamanashiJapan
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Samarasinghe SM, Hewage AS, Siriwardana RC, Tennekoon KH, Niriella MA, De Silva S, Abeysuriya V. Association between single nucleotide polymorphisms in PNPLA3, TM6SF2 and MBOAT7 genes and markers of cancer aggressiveness in a Sri Lankan NASH-related HCC cohort. BMC Gastroenterol 2025; 25:151. [PMID: 40065199 PMCID: PMC11892176 DOI: 10.1186/s12876-025-03738-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2024] [Accepted: 02/26/2025] [Indexed: 03/14/2025] Open
Abstract
BACKGROUND Single nucleotide polymorphisms (SNPs) in patatin-like phospholipase domain-containing protein 3 (PNPLA3), transmembrane 6 superfamily member 2 (TM6SF2) and membrane bound O-acyltransferase domain containing 7 (MBOAT7) genes were reported to be strongly associated with non-alcoholic fatty liver disease (NAFLD) pathogenicity among different populations. We investigated whether these SNPs are associated with prognostic factors and genetic biomarkers of non-alcoholic steatohepatitis (NASH)-related hepatocellular carcinoma (HCC) in the Sri Lankan context. METHODS We conducted an exploratory study to evaluate the prevalence of five SNPs (PNPLA3 rs738409, PNPLA3 rs2281135, PNPLA3 rs2294918, TM6SF2 rs58542926 and MBOAT7 rs641738) as genetic risk factors for NASH-HCC pathogenicity. We genotyped 48 NASH-HCC patient samples collected at a clinical setting using a minisequencing method. Impact of each SNP with tumor prognostic factors such as nodularity, tumor size and AFP (alpha-feto protein) level was analyzed using chi square test. We also analyzed the expression of micro RNA-122 (miR-122) in serum and leukocyte telomere length via quantitative real-time PCR. Associations between each SNP with micro RNA-122 (miR-122) expression level and leukocyte telomere length of NASH-HCC patients were analyzed using one-way analysis of variance (ANOVA) test and independent t test. Relationships among tested SNPs and some well-established HCC risk factors such as age, BMI, gender, diabetes status and the cirrhotic stage were also analyzed using chi square test, independent t-test and One-way ANOVA test. RESULTS Our analyses demonstrated significant associations between PNPLA3 rs2281135 variant and tumor nodularity. Also, PNPLA3 rs2281135 and PNPLA3 rs2294918 variants were significantly associated with miR-122 expression levels of NASH-HCC patients. Further, age and body mass index (BMI) were significantly associated with PNPLA3 rs2281135 variant in our study cohort. CONCLUSION We found that in the Sri Lankan NASH-related HCC cohort, some PNPLA3 variants (rs2281135 and rs2294918) correlate with tumor nodularity, higher miR-122 expression, and distinct demographic features such as age and BMI. Our work highlights the role of specific SNPs in tumor aggressiveness, contributing to the precision screening for HCC in NASH patients.
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Affiliation(s)
- Saumya Madushani Samarasinghe
- Institute of Biochemistry, Molecular Biology and Biotechnology, University of Colombo, No 90, Cumarathunga Munidasa Mawatha, Colombo 03, Sri Lanka
| | - Asanka Sudeshini Hewage
- Institute of Biochemistry, Molecular Biology and Biotechnology, University of Colombo, No 90, Cumarathunga Munidasa Mawatha, Colombo 03, Sri Lanka.
| | | | - Kamani Hemamala Tennekoon
- Institute of Biochemistry, Molecular Biology and Biotechnology, University of Colombo, No 90, Cumarathunga Munidasa Mawatha, Colombo 03, Sri Lanka
| | - Madunil Anuk Niriella
- Colombo North Center for Liver Diseases, Faculty of Medicine, University of Kelaniya, Ragama, Sri Lanka
| | - Sumadee De Silva
- Institute of Biochemistry, Molecular Biology and Biotechnology, University of Colombo, No 90, Cumarathunga Munidasa Mawatha, Colombo 03, Sri Lanka
| | - Visula Abeysuriya
- Institute of Biochemistry, Molecular Biology and Biotechnology, University of Colombo, No 90, Cumarathunga Munidasa Mawatha, Colombo 03, Sri Lanka
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6
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Bayram S, Ülger Y. Association of PNPLA3 rs738409 C > G and rs2896019 T > G Polymorphisms with Nonalcoholic Fatty Liver Disease in a Turkish Population from Adıyaman Province. Genet Test Mol Biomarkers 2025; 29:63-73. [PMID: 40101239 DOI: 10.1089/gtmb.2024.0481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/20/2025] Open
Abstract
Objectives: The purpose of this study was to investigate the effect of patatin-like phospholipase domain-containing protein 3 (PNPLA3) rs738409 C > G and rs2896019 T > G polymorphisms on genetic susceptibility to nonalcoholic fatty liver disease (NAFLD) in a Turkish population from Adıyaman province, located in the Southeast Anatolia Region of Turkey. Materials and Methods: This hospital-based molecular epidemiological case-control study analyzed the PNPLA3 rs738409 C > G and rs2896019 T > G polymorphisms in 335 NAFLD cases and 410 healthy controls. Genotype frequencies were determined using real-time polymerase chain reaction with the TaqMan assay. The association with NAFLD susceptibility was evaluated by calculating odds ratios (ORs) and 95% confidence intervals (CIs) using an unconditional logistic regression model. Results: We found that the PNPLA3 rs738409 C > G (CC vs. GG: OR = 1.90, 95% CI = 1.05-3.44) and rs2896019 T > G (TT vs. GG: OR = 3.24, 95% CI = 1.44-7.27) polymorphisms were linked to an increased risk of NAFLD in almost all genetic models (p < 0.05). In addition, the PNPLA3 Grs738409/Grs2896019 haplotype was associated with NAFLD development (p < 0.05). Significant differences in alanine aminotransferase and aspartate aminotransferase enzyme levels were observed across the genotypes of these polymorphisms (p < 0.05). Conclusion: This is the first study on PNPLA3 single nucleotide polymorphisms (SNPs) and NAFLD in the Turkish population of Adıyaman Province, Southeast Anatolia. Our findings suggest that the PNPLA3 rs738409 C > G and rs2896019 T > G polymorphisms, along with their haplotypes, may influence NAFLD susceptibility. Further independent studies with larger sample sizes and diverse populations are needed to confirm these results.
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Affiliation(s)
- Süleyman Bayram
- Faculty of Health Sciences, Department of Public Health Nursing, Adıyaman University, Adıyaman, Turkey
| | - Yakup Ülger
- Faculty of Medicine, Department of Gastroenterology, Çukurova University, Adana, Turkey
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7
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Sherman DJ, Liu L, Mamrosh JL, Xie J, Ferbas J, Lomenick B, Ladinsky MS, Verma R, Rulifson IC, Deshaies RJ. The fatty liver disease-causing protein PNPLA3-I148M alters lipid droplet-Golgi dynamics. Proc Natl Acad Sci U S A 2024; 121:e2318619121. [PMID: 38657050 PMCID: PMC11067037 DOI: 10.1073/pnas.2318619121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 03/16/2024] [Indexed: 04/26/2024] Open
Abstract
Nonalcoholic fatty liver disease, recently renamed metabolic dysfunction-associated steatotic liver disease (MASLD), is a progressive metabolic disorder that begins with aberrant triglyceride accumulation in the liver and can lead to cirrhosis and cancer. A common variant in the gene PNPLA3, encoding the protein PNPLA3-I148M, is the strongest known genetic risk factor for MASLD. Despite its discovery 20 y ago, the function of PNPLA3, and now the role of PNPLA3-I148M, remain unclear. In this study, we sought to dissect the biogenesis of PNPLA3 and PNPLA3-I148M and characterize changes induced by endogenous expression of the disease-causing variant. Contrary to bioinformatic predictions and prior studies with overexpressed proteins, we demonstrate here that PNPLA3 and PNPLA3-I148M are not endoplasmic reticulum-resident transmembrane proteins. To identify their intracellular associations, we generated a paired set of isogenic human hepatoma cells expressing PNPLA3 and PNPLA3-I148M at endogenous levels. Both proteins were enriched in lipid droplet, Golgi, and endosomal fractions. Purified PNPLA3 and PNPLA3-I148M proteins associated with phosphoinositides commonly found in these compartments. Despite a similar fractionation pattern as the wild-type variant, PNPLA3-I148M induced morphological changes in the Golgi apparatus, including increased lipid droplet-Golgi contact sites, which were also observed in I148M-expressing primary human patient hepatocytes. In addition to lipid droplet accumulation, PNPLA3-I148M expression caused significant proteomic and transcriptomic changes that resembled all stages of liver disease. Cumulatively, we validate an endogenous human cellular system for investigating PNPLA3-I148M biology and identify the Golgi apparatus as a central hub of PNPLA3-I148M-driven cellular change.
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Affiliation(s)
| | - Lei Liu
- Amgen Research, South San Francisco, CA94080
| | | | | | | | - Brett Lomenick
- Proteome Exploration Laboratory, Beckman Institute, California Institute of Technology, Pasadena, CA91125
| | - Mark S. Ladinsky
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA91125
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8
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Konkwo C, Chowdhury S, Vilarinho S. Genetics of liver disease in adults. Hepatol Commun 2024; 8:e0408. [PMID: 38551385 PMCID: PMC10984672 DOI: 10.1097/hc9.0000000000000408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Accepted: 01/30/2024] [Indexed: 04/02/2024] Open
Abstract
Chronic liver disease stands as a significant global health problem with an estimated 2 million annual deaths across the globe. Combining the use of next-generation sequencing technologies with evolving knowledge in the interpretation of genetic variation across the human genome is propelling our understanding, diagnosis, and management of both rare and common liver diseases. Here, we review the contribution of risk and protective alleles to common forms of liver disease, the rising number of monogenic diseases affecting the liver, and the role of somatic genetic variants in the onset and progression of oncological and non-oncological liver diseases. The incorporation of genomic information in the diagnosis and management of patients with liver disease is driving the beginning of a new era of genomics-informed clinical hepatology practice, facilitating personalized medicine, and improving patient care.
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Affiliation(s)
- Chigoziri Konkwo
- Department of Internal Medicine, Section of Digestive Diseases, Yale School of Medicine, New Haven, Connecticut, USA
| | - Shanin Chowdhury
- Department of Internal Medicine, Section of Digestive Diseases, Yale School of Medicine, New Haven, Connecticut, USA
- Department of Pathology, Yale School of Medicine, New Haven, Connecticut, USA
| | - Silvia Vilarinho
- Department of Internal Medicine, Section of Digestive Diseases, Yale School of Medicine, New Haven, Connecticut, USA
- Department of Pathology, Yale School of Medicine, New Haven, Connecticut, USA
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9
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Merenda T, Juszczak F, Ferier E, Duez P, Patris S, Declèves AÉ, Nachtergael A. Natural compounds proposed for the management of non-alcoholic fatty liver disease. NATURAL PRODUCTS AND BIOPROSPECTING 2024; 14:24. [PMID: 38556609 PMCID: PMC10982245 DOI: 10.1007/s13659-024-00445-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 03/20/2024] [Indexed: 04/02/2024]
Abstract
Although non-alcoholic fatty liver disease (NAFLD) presents as an intricate condition characterized by a growing prevalence, the often-recommended lifestyle interventions mostly lack high-level evidence of efficacy and there are currently no effective drugs proposed for this indication. The present review delves into NAFLD pathology, its diverse underlying physiopathological mechanisms and the available in vitro, in vivo, and clinical evidence regarding the use of natural compounds for its management, through three pivotal targets (oxidative stress, cellular inflammation, and insulin resistance). The promising perspectives that natural compounds offer for NAFLD management underscore the need for additional clinical and lifestyle intervention trials. Encouraging further research will contribute to establishing more robust evidence and practical recommendations tailored to patients with varying NAFLD grades.
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Affiliation(s)
- Théodora Merenda
- Unit of Clinical Pharmacy, Research Institute for Health Sciences and Technology, University of Mons (UMONS), Mons, Belgium
| | - Florian Juszczak
- Department of Metabolic and Molecular Biochemistry, Research Institute for Health Sciences and Technology, University of Mons (UMONS), Mons, Belgium
| | - Elisabeth Ferier
- Department of Metabolic and Molecular Biochemistry, Research Institute for Health Sciences and Technology, University of Mons (UMONS), Mons, Belgium
- Unit of Therapeutic Chemistry and Pharmacognosy, Research Institute for Health Sciences and Technology, University of Mons (UMONS), Mons, Belgium
| | - Pierre Duez
- Unit of Therapeutic Chemistry and Pharmacognosy, Research Institute for Health Sciences and Technology, University of Mons (UMONS), Mons, Belgium
| | - Stéphanie Patris
- Unit of Clinical Pharmacy, Research Institute for Health Sciences and Technology, University of Mons (UMONS), Mons, Belgium
| | - Anne-Émilie Declèves
- Department of Metabolic and Molecular Biochemistry, Research Institute for Health Sciences and Technology, University of Mons (UMONS), Mons, Belgium
| | - Amandine Nachtergael
- Unit of Therapeutic Chemistry and Pharmacognosy, Research Institute for Health Sciences and Technology, University of Mons (UMONS), Mons, Belgium.
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10
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Hofer P, Grabner GF, König M, Xie H, Bulfon D, Ludwig AE, Wolinski H, Zimmermann R, Zechner R, Heier C. Cooperative lipolytic control of neuronal triacylglycerol by spastic paraplegia-associated enzyme DDHD2 and ATGL. J Lipid Res 2023; 64:100457. [PMID: 37832604 PMCID: PMC10665947 DOI: 10.1016/j.jlr.2023.100457] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 10/01/2023] [Accepted: 10/04/2023] [Indexed: 10/15/2023] Open
Abstract
Intracellular lipolysis-the enzymatic breakdown of lipid droplet-associated triacylglycerol (TAG)-depends on the cooperative action of several hydrolytic enzymes and regulatory proteins, together designated as lipolysome. Adipose triglyceride lipase (ATGL) acts as a major cellular TAG hydrolase and core effector of the lipolysome in many peripheral tissues. Neurons initiate lipolysis independently of ATGL via DDHD domain-containing 2 (DDHD2), a multifunctional lipid hydrolase whose dysfunction causes neuronal TAG deposition and hereditary spastic paraplegia. Whether and how DDHD2 cooperates with other lipolytic enzymes is currently unknown. In this study, we further investigated the enzymatic properties and functions of DDHD2 in neuroblastoma cells and primary neurons. We found that DDHD2 hydrolyzes multiple acylglycerols in vitro and substantially contributes to neutral lipid hydrolase activities of neuroblastoma cells and brain tissue. Substrate promiscuity of DDHD2 allowed its engagement at different steps of the lipolytic cascade: In neuroblastoma cells, DDHD2 functioned exclusively downstream of ATGL in the hydrolysis of sn-1,3-diacylglycerol (DAG) isomers but was dispensable for TAG hydrolysis and lipid droplet homeostasis. In primary cortical neurons, DDHD2 exhibited lipolytic control over both, DAG and TAG, and complemented ATGL-dependent TAG hydrolysis. We conclude that neuronal cells use noncanonical configurations of the lipolysome and engage DDHD2 as dual TAG/DAG hydrolase in cooperation with ATGL.
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Affiliation(s)
- Peter Hofer
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Gernot F Grabner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Mario König
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Hao Xie
- Institute of Molecular Biosciences, University of Graz, Graz, Austria; State Key Laboratory of Natural Medicines, Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing, China
| | - Dominik Bulfon
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Anton E Ludwig
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Heimo Wolinski
- Institute of Molecular Biosciences, University of Graz, Graz, Austria; BioHealth Field of Excellence, University of Graz, Graz, Austria
| | - Robert Zimmermann
- Institute of Molecular Biosciences, University of Graz, Graz, Austria; BioHealth Field of Excellence, University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria; BioHealth Field of Excellence, University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Christoph Heier
- Institute of Molecular Biosciences, University of Graz, Graz, Austria; BioHealth Field of Excellence, University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria.
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11
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Sherman DJ, Liu L, Mamrosh JL, Xie J, Ferbas J, Lomenick B, Ladinsky MS, Verma R, Rulifson IC, Deshaies RJ. The fatty liver disease-causing protein PNPLA3-I148M alters lipid droplet-Golgi dynamics. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.13.562302. [PMID: 37873239 PMCID: PMC10592801 DOI: 10.1101/2023.10.13.562302] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Non-alcoholic fatty liver disease (NAFLD), recently renamed metabolic dysfunction-associated steatotic liver disease (MASLD), is a progressive metabolic disorder that begins with aberrant triglyceride accumulation in the liver and can lead to cirrhosis and cancer. A common variant in the gene PNPLA3, encoding the protein PNPLA3-I148M, is the strongest known genetic risk factor for MASLD to date. Despite its discovery twenty years ago, the function of PNPLA3, and now the role of PNPLA3-I148M, remain unclear. In this study, we sought to dissect the biogenesis of PNPLA3 and PNPLA3-I148M and characterize changes induced by endogenous expression of the disease-causing variant. Contrary to bioinformatic predictions and prior studies with overexpressed proteins, we demonstrate here that PNPLA3 and PNPLA3-I148M are not endoplasmic reticulum-resident transmembrane proteins. To identify their intracellular associations, we generated a paired set of isogenic human hepatoma cells expressing PNPLA3 and PNPLA3-I148M at endogenous levels. Both proteins were enriched in lipid droplet, Golgi, and endosomal fractions. Purified PNPLA3 and PNPLA3-I148M proteins associated with phosphoinositides commonly found in these compartments. Despite a similar fractionation pattern as the wild-type variant, PNPLA3-I148M induced morphological changes in the Golgi apparatus, including increased lipid droplet-Golgi contact sites, which were also observed in I148M-expressing primary human patient hepatocytes. In addition to lipid droplet accumulation, PNPLA3-I148M expression caused significant proteomic and transcriptomic changes that resembled all stages of liver disease. Cumulatively, we validate an endogenous human cellular system for investigating PNPLA3-I148M biology and identify the Golgi apparatus as a central hub of PNPLA3-I148M-driven cellular change.
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Affiliation(s)
| | - Lei Liu
- Amgen Research, South San Francisco, CA 94080, USA
| | | | | | - John Ferbas
- Amgen Research, Thousand Oaks, CA 91320, USA
| | - Brett Lomenick
- Proteome Exploration Laboratory, California Institute of Technology, Pasadena, CA 91125, USA
| | - Mark S. Ladinsky
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Rati Verma
- Amgen Research, Thousand Oaks, CA 91320, USA
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12
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Samarasinghe SM, Hewage AS, Siriwardana RC, Tennekoon KH, Niriella MA, De Silva S. Genetic and metabolic aspects of non-alcoholic fatty liver disease (NAFLD) pathogenicity. EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2023; 24:53. [DOI: 10.1186/s43042-023-00433-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 08/21/2023] [Indexed: 01/03/2025] Open
Abstract
Abstract
Background
Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease showing a rising prevalence globally. Genetic predisposition plays a key role in the development and progression of the disease pathogenicity.
Main body
This paper summarizes genetic associations based on their influence on several metabolic aspects such as lipid metabolism, glucose metabolism, hepatic iron accumulation and cholesterol metabolism toward the NAFLD pathogenicity. Furthermore, we present variations in some epigenetic characters and the microRNA profile with regard to NAFLD.
Conclusion
As reported in many studies, the PNPLA3 rs738409 variant seems to be significantly associated with NAFLD susceptibility. Other gene variants like TM6SF2 rs58542926, MBOAT7 rs641738 and GCKR variants also appear to be more prevalent among NAFLD patients. We believe these genetic variants may provide insights into new trends in developing noninvasive biomarkers and identify their suitability in clinical practice in the future.
Graphical abstract
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13
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Grander C, Grabherr F, Tilg H. Non-alcoholic fatty liver disease: pathophysiological concepts and treatment options. Cardiovasc Res 2023; 119:1787-1798. [PMID: 37364164 PMCID: PMC10405569 DOI: 10.1093/cvr/cvad095] [Citation(s) in RCA: 66] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 11/30/2022] [Accepted: 06/23/2023] [Indexed: 06/28/2023] Open
Abstract
The prevalence of non-alcoholic fatty liver disease (NAFLD) is continually increasing due to the global obesity epidemic. NAFLD comprises a systemic metabolic disease accompanied frequently by insulin resistance and hepatic and systemic inflammation. Whereas simple hepatic steatosis is the most common disease manifestation, a more progressive disease course characterized by liver fibrosis and inflammation (i.e. non-alcoholic steatohepatitis) is present in 10-20% of affected individuals. NAFLD furthermore progresses in a substantial number of patients towards liver cirrhosis and hepatocellular carcinoma. Whereas this disease now affects almost 25% of the world's population and is mainly observed in obesity and type 2 diabetes, NAFLD also affects lean individuals. Pathophysiology involves lipotoxicity, hepatic immune disturbances accompanied by hepatic insulin resistance, a gut dysbiosis, and commonly hepatic and systemic insulin resistance defining this disorder a prototypic systemic metabolic disorder. Not surprisingly many affected patients have other disease manifestations, and indeed cardiovascular disease, chronic kidney disease, and extrahepatic malignancies are all contributing substantially to patient outcome. Weight loss and lifestyle change reflect the cornerstone of treatment, and several medical treatment options are currently under investigation. The most promising treatment strategies include glucagon-like peptide 1 receptor antagonists, sodium-glucose transporter 2 inhibitors, Fibroblast Growth Factor analogues, Farnesoid X receptor agonists, and peroxisome proliferator-activated receptor agonists. Here, we review epidemiology, pathophysiology, and therapeutic options for NAFLD.
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Affiliation(s)
- Christoph Grander
- Department of Internal Medicine I, Gastroenterology, Hepatology, Endocrinology & Metabolism, Medical University Innsbruck, Anichstrasse 35, Innsbruck 6020, Austria
| | - Felix Grabherr
- Department of Internal Medicine I, Gastroenterology, Hepatology, Endocrinology & Metabolism, Medical University Innsbruck, Anichstrasse 35, Innsbruck 6020, Austria
| | - Herbert Tilg
- Department of Internal Medicine I, Gastroenterology, Hepatology, Endocrinology & Metabolism, Medical University Innsbruck, Anichstrasse 35, Innsbruck 6020, Austria
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14
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Lulić AM, Katalinić M. The PNPLA family of enzymes: characterisation and biological role. Arh Hig Rada Toksikol 2023; 74:75-89. [PMID: 37357879 PMCID: PMC10291501 DOI: 10.2478/aiht-2023-74-3723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 02/01/2023] [Accepted: 05/01/2023] [Indexed: 06/27/2023] Open
Abstract
This paper brings a brief review of the human patatin-like phospholipase domain-containing protein (PNPLA) family. Even though it consists of only nine members, their physiological roles and mechanisms of their catalytic activity are not fully understood. However, the results of a number of knock-out and gain- or loss-of-function research models suggest that these enzymes have an important role in maintaining the homeostasis and integrity of organelle membranes, in cell growth, signalling, cell death, and the metabolism of lipids such as triacylglycerol, phospholipids, ceramides, and retinyl esters. Research has also revealed a connection between PNPLA family member mutations or irregular catalytic activity and the development of various diseases. Here we summarise important findings published so far and discuss their structure, localisation in the cell, distribution in the tissues, specificity for substrates, and their potential physiological role, especially in view of their potential as drug targets.
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Affiliation(s)
- Ana-Marija Lulić
- Institute for Medical Research and Occupational Health, Biochemistry and Organic Analytical Chemistry Unit, Zagreb, Croatia
| | - Maja Katalinić
- Institute for Medical Research and Occupational Health, Biochemistry and Organic Analytical Chemistry Unit, Zagreb, Croatia
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15
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Cano A, Vazquez-Chantada M, Conde-Vancells J, Gonzalez-Lahera A, Mosen-Ansorena D, Blanco FJ, Clément K, Aron-Wisnewsky J, Tran A, Gual P, García-Monzón C, Caballería J, Castro A, Martínez-Chantar ML, Mato JM, Zhu H, Finnell RH, Aransay AM. Impaired Function of Solute Carrier Family 19 Leads to Low Folate Levels and Lipid Droplet Accumulation in Hepatocytes. Biomedicines 2023; 11:biomedicines11020337. [PMID: 36830876 PMCID: PMC9953281 DOI: 10.3390/biomedicines11020337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/17/2023] [Accepted: 01/18/2023] [Indexed: 01/27/2023] Open
Abstract
Low serum folate levels are inversely related to metabolic associated fatty liver disease (MAFLD). The role of the folate transporter gene (SLC19A1) was assessed to clarify its involvement in lipid accumulation during the onset of MAFLD in humans and in liver cells by genomic, transcriptomic, and metabolomic techniques. Genotypes of 3 SNPs in a case-control cohort were initially correlated to clinical and serum MAFLD markers. Subsequently, the expression of 84 key genes in response to the loss of SLC19A1 was evaluated with the aid of an RT2 profiler-array. After shRNA-silencing of SLC19A1 in THLE2 cells, folate and lipid levels were measured by ELISA and staining techniques, respectively. In addition, up to 482 amino acids and lipid metabolites were semi-quantified in SLC19A1-knockdown (KD) cells through ultra-high-performance liquid chromatography coupled with mass spectrometry. SNPs, rs1051266 and rs3788200, were significantly associated with the development of fatty liver for the single-marker allelic test. The minor alleles of these SNPs were associated with a 0.6/-1.67-fold decreased risk of developing MAFLD. When SLC19A1 was KD in THLE2 cells, intracellular folate content was four times lower than in wild-type cells. The lack of functional SLC19A1 provoked significant changes in the regulation of genes associated with lipid droplet accumulation within the cell and the onset of NAFLD. Metabolomic analyses showed a highly altered profile, where most of the species that accumulated in SLC19A1-KD-cells belong to the chemical groups of triacylglycerols, diacylglycerols, polyunsaturated fatty acids, and long chain, highly unsaturated cholesterol esters. In conclusion, the lack of SLC19A1 gene expression in hepatocytes affects the regulation of key genes for normal liver function, reduces intracellular folate levels, and impairs lipid metabolism, which entails lipid droplet accumulation in hepatocytes.
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Affiliation(s)
- Ainara Cano
- Food Research, AZTI, Basque Research and Technology Alliance (BRTA), Parque Tecnologico de Bizkaia, Astondo Bidea, Building 609, 48160 Derio, Spain
- OWL Metabolomics, Parque Tecnologico de Bizkaia, Building 502, 48160 Derio, Spain
| | - Mercedes Vazquez-Chantada
- OWL Metabolomics, Parque Tecnologico de Bizkaia, Building 502, 48160 Derio, Spain
- Department of Nutritional Sciences, Dell Paediatric Research Institute, The University of Texas at Austin, Austin, TX 78712, USA
| | - Javier Conde-Vancells
- Department of Nutritional Sciences, Dell Paediatric Research Institute, The University of Texas at Austin, Austin, TX 78712, USA
| | - Aintzane Gonzalez-Lahera
- CIC bioGUNE, Parque Tecnologico de Bizkaia, Building 801-A, 48160 Derio, Spain
- CIBERehd, ISCIII, 28029 Madrid, Spain
| | | | - Francisco J. Blanco
- CIC bioGUNE, Parque Tecnologico de Bizkaia, Building 801-A, 48160 Derio, Spain
- Ikerbasque, Basque Foundation for Science, 48009 Bilbao, Spain
| | - Karine Clément
- Nutriomics Research Group, Nutrition Department, Pitié-Salpétrière Hospital, INSERM, Sorbonne Université, F-75013 Paris, France
- INSERM, UMR_S 1166, NutriOmics Team 6, F-75013 Paris, France
- Assistance Publique Hôpitaux de Paris, Nutrition department ICAN and CRNH-Ile de France, Pitié-Salpêtrière Hospital, F-75013 Paris, France
| | - Judith Aron-Wisnewsky
- Nutriomics Research Group, Nutrition Department, Pitié-Salpétrière Hospital, INSERM, Sorbonne Université, F-75013 Paris, France
- INSERM, UMR_S 1166, NutriOmics Team 6, F-75013 Paris, France
- Assistance Publique Hôpitaux de Paris, Nutrition department ICAN and CRNH-Ile de France, Pitié-Salpêtrière Hospital, F-75013 Paris, France
| | - Albert Tran
- Team 8 “Chronic Liver Diseases Associated with Obesity and Alcohol”, INSERM, U1065, Centre Hospitalier Universitaire de Nice, C3M, Université Côte d’Azur, 06000 Nice, France
| | - Philippe Gual
- Team 8 “Chronic Liver Diseases Associated with Obesity and Alcohol”, INSERM, U1065, Centre Hospitalier Universitaire de Nice, C3M, Université Côte d’Azur, 06000 Nice, France
| | - Carmelo García-Monzón
- CIBERehd, ISCIII, 28029 Madrid, Spain
- Liver Research Unit, Santa Cristina University Hospital, Instituto de Investigación Sanitaria Princesa, 28009 Madrid, Spain
| | - Joan Caballería
- CIBERehd, ISCIII, 28029 Madrid, Spain
- Liver Unit, Hospital Clinic, 08036 Barcelona, Spain
| | - Azucena Castro
- OWL Metabolomics, Parque Tecnologico de Bizkaia, Building 502, 48160 Derio, Spain
| | - María Luz Martínez-Chantar
- CIC bioGUNE, Parque Tecnologico de Bizkaia, Building 801-A, 48160 Derio, Spain
- CIBERehd, ISCIII, 28029 Madrid, Spain
| | - José M. Mato
- CIC bioGUNE, Parque Tecnologico de Bizkaia, Building 801-A, 48160 Derio, Spain
- CIBERehd, ISCIII, 28029 Madrid, Spain
| | - Huiping Zhu
- Department of Nutritional Sciences, Dell Paediatric Research Institute, The University of Texas at Austin, Austin, TX 78712, USA
| | - Richard H. Finnell
- Department of Nutritional Sciences, Dell Paediatric Research Institute, The University of Texas at Austin, Austin, TX 78712, USA
| | - Ana M. Aransay
- CIC bioGUNE, Parque Tecnologico de Bizkaia, Building 801-A, 48160 Derio, Spain
- CIBERehd, ISCIII, 28029 Madrid, Spain
- Correspondence: ; Tel.: +34-944-061-325 or +34-946-572-524; Fax: +34-946-572-530
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Chen Y, Yan X, Wang T, Deng H, Deng X, Xu F, Liang H. PNPLA3 148M/M Is More Susceptible to Palmitic Acid-Induced Endoplasmic Reticulum Stress-Associated Apoptosis in HepG2 Cells. Int J Endocrinol 2023; 2023:2872408. [PMID: 36825197 PMCID: PMC9943609 DOI: 10.1155/2023/2872408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 11/16/2022] [Accepted: 11/22/2022] [Indexed: 02/16/2023] Open
Abstract
BACKGROUND Patatin-like phospholipase domain-containing 3 (PNPLA3) is a major susceptibility gene for nonalcoholic fatty liver disease (NAFLD), and its rs738409 (I148M) polymorphism is associated with the occurrence and progression of NAFLD. Endoplasmic reticulum (ER) stress-related hepatocyte lipoapoptosis contributes to the progress of NAFLD. PNPLA3 is also known as a member of the calcium-independent phospholipase A2ε family, which can hydrolyze fatty acids to generate lysophosphatidylcholine (LPC) that induces ER stress-related hepatocyte lipoapoptosis. Whether the PNPLA3 risk genotype 148M/M is involved in more severe ER stress-associated lipoapoptosis is unclear. METHODS A PNPLA3148I knock-in HepG2 cell model was constructed based on HepG2 expressing PNPLA3 148M/M using the Cas9/sgRNA system. PNPLA3 148M/M, I/M, and I/I cells were treated with 0.3 mM palmitic acid (PA) for 24 h to induce lipid deposition. Cellular lipid deposition was detected by oil red staining. Apoptosis was observed by TUNEL. LPC was determined by ELISA, and the expression of PNPLA3, the ER stress marker Bip, molecules involved in the ER stress PERK/elF-2a pathway, and its downstream C/EBP homologous protein (CHOP)-mediated apoptotic pathway were detected by western blot. RESULTS The results showed no difference in PNPLA3 basal expression and basal hepatocyte lipid content between the three genotypes of cells. Lipid deposition and apoptosis were more severe in PNPLA3 148M/M and 148I/M cells than in I/I cells after PA treatment. PA-induced upregulation of protein expression of Bip, ER stress-responsive PERK pathway molecules p-PERK, p-eIF2α, CHOP, and CHOP-associated apoptotic molecules PUMA and Bax were more pronounced in PNPLA3 148M/M cells than in PNPLA3 148I/I cells. The basal LPC levels and the PA-treated increase of LPC levels in the cell culture supernatants did not differ between the three genotypic cells. CONCLUSION PNPLA3 148M/M cells were more susceptible to PA-induced lipid deposition and ER stress-related apoptosis than 148I/I cells, and the proapoptotic susceptibility of PNPLA3 148M/M is independent of LPC.
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Affiliation(s)
- Yunzhi Chen
- Department of Endocrinology and Metabolism, Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou 510630, China
- Guangdong Provincial People's Hospital, Guangzhou 510080, China
| | - Xuemei Yan
- Department of Endocrinology and Metabolism, Joint Service Support Force 903 Hospital, Hangzhou 310005, China
| | - Tian Wang
- Department of Endocrinology and Metabolism, Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou 510630, China
| | - Hongrong Deng
- Department of Endocrinology and Metabolism, Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou 510630, China
| | - Xiaojie Deng
- Department of Endocrinology and Metabolism, Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou 510630, China
| | - Fen Xu
- Department of Endocrinology and Metabolism, Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou 510630, China
| | - Hua Liang
- Department of Endocrinology and Metabolism, Third Affiliated Hospital of Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou 510630, China
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17
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Association of rs738409 Polymorphism in Adiponutrin Gene with Liver Steatosis and Atherosclerosis Risk Factors in Greek Children and Adolescents. Nutrients 2022; 14:nu14173452. [PMID: 36079710 PMCID: PMC9459993 DOI: 10.3390/nu14173452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 08/17/2022] [Accepted: 08/18/2022] [Indexed: 12/03/2022] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) shares several risk factors with atherosclerosis, as it is associated with components of the metabolic syndrome. However, genetic variations have also been linked to the risk of NAFLD, such as adiponutrin/patatin-like phospholipase domain-containing the protein 3 (PNPLA3) rs738409 polymorphism. The aim of the study was to determine the associations of thePNPLA3 rs738409 polymorphism with NAFLD and atherosclerosis risk factors in children and adolescents from northern Greece. A total of 91 children/adolescents who followed a Mediterranean eating pattern with no particular restrictions were studied. They were divided into three subgroups, according to their body mass index (BMI) and the presence or absence of liver disease. Diagnosis of NAFLD was based on a liver ultrasound, while the distribution of the PNPLA3 rs738409 polymorphism was investigated in all the participants. From the components of metabolic syndrome, only BMI, waist circumference, blood pressure, and the homeostasis model of insulin resistance (HOMA-IR) differed significantly between groups. The rs738409 polymorphism was significantly associated with BMI and NAFLD, while lipid values had no significant association with either NAFLD or gene polymorphism. This study shows that in Greekchildren, there is a significant association between the rs738409polymorphism in the PNPLA3 gene and hepatic steatosis, regardless of bodyweight.
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18
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Willis SA, Bawden SJ, Malaikah S, Sargeant JA, Stensel DJ, Aithal GP, King JA. The role of hepatic lipid composition in obesity-related metabolic disease. Liver Int 2021; 41:2819-2835. [PMID: 34547171 DOI: 10.1111/liv.15059] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 09/15/2021] [Accepted: 09/17/2021] [Indexed: 12/14/2022]
Abstract
Obesity is a primary antecedent to non-alcoholic fatty liver disease whose cardinal feature is excessive hepatic lipid accumulation. Although total hepatic lipid content closely associates with hepatic and systemic metabolic dysfunction, accumulating evidence suggests that the composition of hepatic lipids may be more discriminatory. This review summarises cross-sectional human studies using liver biopsy/lipidomics and proton magnetic resonance spectroscopy to characterise hepatic lipid composition in people with obesity and related metabolic disease. A comprehensive literature search identified 26 relevant studies published up to 31st March 2021 which were included in the review. The available evidence provides a consistent picture showing that people with hepatic steatosis possess elevated saturated and/or monounsaturated hepatic lipids and a reduced proportion of polyunsaturated hepatic lipids. This altered hepatic lipid profile associates more directly with metabolic derangements, such as insulin resistance, and may be exacerbated in non-alcoholic steatohepatitis. Further evidence from lipidomic studies suggests that these deleterious changes may be related to defects in lipid desaturation and elongation, and an augmentation of the de novo lipogenic pathway. These observations are consistent with mechanistic studies implicating saturated fatty acids and associated bioactive lipid intermediates (ceramides, lysophosphatidylcholines and diacylglycerol) in the development of hepatic lipotoxicity and wider metabolic dysfunction, whilst monounsaturated fatty acids and polyunsaturated fatty acids may exhibit a protective role. Future studies are needed to prospectively determine the relevance of hepatic lipid composition for hepatic and non-hepatic morbidity and mortality; and to further evaluate the impact of therapeutic interventions such as pharmacotherapy and lifestyle interventions.
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Affiliation(s)
- Scott A Willis
- National Centre for Sport and Exercise Medicine, School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK.,NIHR Leicester Biomedical Research Centre, University Hospitals of Leicester NHS Trust and University of Leicester, Leicester, UK
| | - Stephen J Bawden
- Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, UK.,NIHR Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and the University of Nottingham, Leicester, UK
| | - Sundus Malaikah
- National Centre for Sport and Exercise Medicine, School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK.,NIHR Leicester Biomedical Research Centre, University Hospitals of Leicester NHS Trust and University of Leicester, Leicester, UK.,Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Jack A Sargeant
- NIHR Leicester Biomedical Research Centre, University Hospitals of Leicester NHS Trust and University of Leicester, Leicester, UK.,Diabetes Research Centre, University of Leicester, Leicester, UK
| | - David J Stensel
- National Centre for Sport and Exercise Medicine, School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK.,NIHR Leicester Biomedical Research Centre, University Hospitals of Leicester NHS Trust and University of Leicester, Leicester, UK
| | - Guruprasad P Aithal
- NIHR Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and the University of Nottingham, Leicester, UK.,Nottingham Digestive Diseases Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - James A King
- National Centre for Sport and Exercise Medicine, School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK.,NIHR Leicester Biomedical Research Centre, University Hospitals of Leicester NHS Trust and University of Leicester, Leicester, UK
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19
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Correlations between PNPLA3 Gene Polymorphisms and NAFLD in Type 2 Diabetic Patients. MEDICINA (KAUNAS, LITHUANIA) 2021; 57:medicina57111249. [PMID: 34833467 PMCID: PMC8620174 DOI: 10.3390/medicina57111249] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 11/03/2021] [Accepted: 11/12/2021] [Indexed: 12/20/2022]
Abstract
Background and Objectives: Non-alcoholic fatty liver disease is a worldwide significant public health problem, particularly in patients with type 2 diabetes mellitus. Identifying possible risk factors for the disease is mandatory for a better understandingand management of this condition. Patatin-like phospholipase domain-containing protein 3 (PNPLA3) has been linked to the development and evolution of fatty liver but not to insulin resistance. The aim of this study isto evaluate the relationships between PNPLA3 and fatty liver, metabolic syndrome and subclinical atherosclerosis. Materials and Methods: The study group consisted of patients with type 2 diabetes mellitus without insulin treatment. The degree of liver fat loading was assessed by ultrasonography, and subclinical atherosclerosis was assessed using carotid intima-media thickness (CIMT). PNPLA3 rs738409 genotype determination was performed by high-resolution melting analysis that allowed three standard genotypes: CC, CG, and GG. Results: Among the 92 patients, more than 90% showed various degrees of hepatic steatosis, almost 62% presented values over the normal limit for the CIMT. The majority of the included subjects met the criteria for metabolic syndrome. Genotyping of PNPLA3 in 68 patients showed that the difference between subjects without steatosis and subjects with hepatic steatosis was due to the higher frequency of genotype GG. The CC genotype was the most common in the group we studied and was significantly more frequent in the group of subjects with severe steatosis; the GG genotype was significantly more frequent in subjects with moderate steatosis; the frequency of the CG genotype was not significantly different among the groups.When we divided the group of subjects into two groups: those with no or mild steatosis and those with moderate or severe steatosis it was shown that the frequency of the GG genotype was significantly higher in the group of subjects with moderate or severe steatosis. PNPLA3 genotypes were not associated with metabolic syndrome, subclinical atherosclerosis, or insulin resistance. Conclusions: Our results suggest that PNPLA3 does not independently influence cardiovascular risk in patients with type 2 diabetes mellitus. The hypothesis that PNPLA3 may have a cardioprotective effect requires future confirmation.
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20
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Xiang H, Wu Z, Wang J, Wu T. Research progress, challenges and perspectives on PNPLA3 and its variants in Liver Diseases. J Cancer 2021; 12:5929-5937. [PMID: 34476007 PMCID: PMC8408107 DOI: 10.7150/jca.57951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 07/26/2021] [Indexed: 12/02/2022] Open
Abstract
The human patatin-like phospholipase domain-containing 3 gene (PNPLA3) is highly expressed in liver and adipose tissue and encodes a transmembrane polypeptide chain containing 481 amino acids. The I148M variant of PNPLA3 is a single nucleotide polymorphism, which is related to a variety of liver and cardiovascular diseases and their complications (such as non-alcoholic fatty liver disease, liver fibrosis, coronary artery disease). This review mainly describes the pathophysiological effects of PNPLA3 and its variants, and their roles in the progression of liver disease and its complications.
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Affiliation(s)
- Hongjiao Xiang
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Zecheng Wu
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Junmin Wang
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Tao Wu
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
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21
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Abstract
Helicobacter pylori is the most prevalent infection worldwide, while non-alcoholic fatty liver disease emerged as the most frequent liver disease. The common occurrence can be either by chance or due to certain pathogenetic factors. Epidemiologic studies revealed that the risk of non-alcoholic liver disease is increased in patients infected with Helicobacter pylori. DNA fragments of Helicobacter pylori were rarely identified in human samples of liver carcinoma and fatty liver. Helicobacter pylori could influence the development of non-alcoholic fatty liver either by hormonal (ghrelin? gastrin? insulin?), or by effect of pro-inflammatory cytokines (interleukin 1 and 8, tumor necrosis factor ɑ, interferon ɣ) and by changes of gut microbiome as well. Probiotic supplementation could improve some clinical parameters of non-alcoholic fatty liver disease and eradication rates of Helicobacter pylori. Regimens used for eradication can be safely administered, although non-alcoholic fatty liver increases the risk of drug-induced liver damage. Controlled studies of the effect of eradication on the development and progression of non-alcoholic fatty liver are warranted.
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Affiliation(s)
- György M Buzás
- Department of Gastroenterology, Ferencváros Health Center, Budapest, Hungary -
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22
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Longo M, Meroni M, Paolini E, Macchi C, Dongiovanni P. Mitochondrial dynamics and nonalcoholic fatty liver disease (NAFLD): new perspectives for a fairy-tale ending? Metabolism 2021; 117:154708. [PMID: 33444607 DOI: 10.1016/j.metabol.2021.154708] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 01/05/2021] [Accepted: 01/07/2021] [Indexed: 12/12/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD) includes a broad spectrum of liver dysfunctions and it is predicted to become the primary cause of liver failure and hepatocellular carcinoma. Mitochondria are highly dynamic organelles involved in multiple metabolic/bioenergetic pathways in the liver. Emerging evidence outlined that hepatic mitochondria adapt in number and functionality in response to external cues, as high caloric intake and obesity, by modulating mitochondrial biogenesis, and maladaptive mitochondrial response has been described from the early stages of NAFLD. Indeed, mitochondrial plasticity is lost in progressive NAFLD and these organelles may assume an aberrant phenotype to drive or contribute to hepatocarcinogenesis. Severe alimentary regimen and physical exercise represent the cornerstone for NAFLD care, although the low patients' compliance is urging towards the discovery of novel pharmacological treatments. Mitochondrial-targeted drugs aimed to recover mitochondrial lifecycle and to modulate oxidative stress are becoming attractive molecules to be potentially introduced for NAFLD management. Although the path guiding the switch from bench to bedside remains tortuous, the study of mitochondrial dynamics is providing intriguing perspectives for future NAFLD healthcare.
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Affiliation(s)
- Miriam Longo
- General Medicine and Metabolic Diseases, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Pad. Granelli, via F Sforza 35, 20122 Milan, Italy; Department of Clinical Sciences and Community Health, Università degli Studi di Milano, 20122 Milano, Italy
| | - Marica Meroni
- General Medicine and Metabolic Diseases, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Pad. Granelli, via F Sforza 35, 20122 Milan, Italy; Department of Pathophysiology and Transplantation, Università degli Studi di Milano, 20122 Milano, Italy
| | - Erika Paolini
- General Medicine and Metabolic Diseases, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Pad. Granelli, via F Sforza 35, 20122 Milan, Italy; Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20133 Milano, Italy
| | - Chiara Macchi
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20133 Milano, Italy
| | - Paola Dongiovanni
- General Medicine and Metabolic Diseases, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Pad. Granelli, via F Sforza 35, 20122 Milan, Italy.
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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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Role of fatty acid elongase Elovl6 in the regulation of energy metabolism and pathophysiological significance in diabetes. Diabetol Int 2020; 12:68-73. [PMID: 33479581 DOI: 10.1007/s13340-020-00481-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 11/30/2020] [Indexed: 12/12/2022]
Abstract
Type 2 diabetes mellitus (T2DM) is an expanding epidemic, closely linked to obesity. Peripheral insulin resistance and impaired insulin secretion remain the core defects in T2DM. Despite significant advances in unraveling the underlying these defects, many of the metabolic pathways and regulators involved in insulin resistance and β-cell dysfunction are not completely understood. This review proposes that manipulating the fatty acid (FA) composition by blocking ELOVL fatty acid elongase 6 (Elovl6) could protect against insulin resistance, impaired insulin secretion, and obesity-related disorders. The molecular mechanism of this new paradigm is also discussed. Elovl6 is a microsomal enzyme involved in the elongation of C16 saturated and monounsaturated FAs to form C18 FAs. We have reported that mice with Elovl6 deletion are protected against obesity-induced insulin resistance or β-cell failure when mated to leptin receptor-deficient db/db mice because the cellular FA composition is changed, even with concurrent obesity. Therefore, Elovl6 appears to be a crucial metabolic checkpoint, and limiting Elovl6 expression or activity could be a new therapeutic approach to treat T2DM.
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Banini BA, Kumar DP, Cazanave S, Seneshaw M, Mirshahi F, Santhekadur PK, Wang L, Guan HP, Oseini A, Alonso C, Bedossa P, Koduru SV, Min HK, Sanyal AJ. Identification of a Metabolic, Transcriptomic, and Molecular Signature of Patatin-Like Phospholipase Domain Containing 3-Mediated Acceleration of Steatohepatitis. Hepatology 2020; 73:1290-1306. [PMID: 33131062 PMCID: PMC8046714 DOI: 10.1002/hep.31609] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 09/23/2020] [Accepted: 10/01/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND AIMS The mechanisms by which the I148M mutant variant of the patatin-like phospholipase domain-containing 3 (PNPLA3I148M ) drives development of nonalcoholic steatohepatitis (NASH) are not known. The aim of this study was to obtain insights on mechanisms underlying PNPLA3I148M -induced acceleration of NASH. APPROACH AND RESULTS Hepatocyte-specific overexpression of empty vector (luciferase), human wild-type PNPLA3, or PNPLA3I148M was achieved using adeno-associated virus 8 in a diet-induced mouse model of nonalcoholic fatty liver disease followed by chow diet or high-fat Western diet with ad libitum administration of sugar in drinking water (WDSW) for 8 weeks. Under WDSW, PNPLA3I148M overexpression accelerated steatohepatitis with increased steatosis, inflammation ballooning, and fibrosis (P < 0.001 versus other groups for all). Silencing PNPLA3I148M after its initial overexpression abrogated these findings. PNPLA3I148M caused 22:6n3 docosahexanoic acid depletion and increased ceramides under WDSW in addition to increasing triglycerides and diglycerides, especially enriched with unsaturated fatty acids. It also increased oxidative stress and endoplasmic reticulum stress. Increased total ceramides was associated with signature of transducer and activator of transcription 3 (STAT3) activation with downstream activation of multiple immune-inflammatory pathways at a transcriptomic level by network analyses. Silencing PNPLA3I148M reversed STAT3 activation. Conditioned media from HepG2 cells overexpressing PNPLA3I148M increased procollagen mRNA expression in LX2 cells; this was abrogated by hepatocyte STAT3 inhibition. CONCLUSIONS Under WDSW, PNPLA3I148M overexpression promotes steatosis and NASH by metabolic reprogramming characterized by increased triglycerides and diglycerides, n3 polyunsaturated fatty acid depletion, and increased ceramides with resultant STAT3 phosphorylation and downstream inflammatory pathway activation driving increased stellate cell fibrogenic activity.
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Affiliation(s)
- Bubu A Banini
- Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University, Richmond, VA, USA,Section of Digestive Diseases, Yale University, New Haven, CT, USA
| | - Divya. P. Kumar
- Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University, Richmond, VA, USA,Department of Biochemistry, CEMR, JSS Medical College, JSS Academy of Higher Education and Research, Mysore, Karnataka, India
| | - Sophie Cazanave
- Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University, Richmond, VA, USA,Glympse Bio, Cambridge, MA, USA
| | - Mulugeta Seneshaw
- Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University, Richmond, VA, USA
| | - Faridoddin Mirshahi
- Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University, Richmond, VA, USA
| | - Prasanna K. Santhekadur
- Department of Biochemistry, CEMR, JSS Medical College, JSS Academy of Higher Education and Research, Mysore, Karnataka, India
| | | | | | - Abdul Oseini
- Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University, Richmond, VA, USA
| | - Cristina Alonso
- OWL Metabolomics, Technology Park of Bizkaia, Derio, Bizkaia, Spain
| | - Pierre Bedossa
- Department of Pathology, Physiology and Imaging, University Paris Diderot, Paris, France
| | - Srinivas V. Koduru
- Gene Arrays, Entity of Vedic Research, New York, NY, USA,Department of Surgery, Penn State College of Medicine, Hershey, PA, USA
| | - Hae-Ki Min
- Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University, Richmond, VA, USA
| | - Arun J. Sanyal
- Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University, Richmond, VA, USA
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Marin-Alejandre BA, Abete I, Monreal JI, Elorz M, Benito-Boillos A, Herrero JI, Navarro-Blasco I, Tur JA, Bandarra NM, Zulet MA, Martinez JA. Effects of a 6-month dietary-induced weight loss on erythrocyte membrane omega-3 fatty acids and hepatic status of subjects with nonalcoholic fatty liver disease: The Fatty Liver in Obesity study. J Clin Lipidol 2020; 14:837-849.e2. [DOI: 10.1016/j.jacl.2020.08.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 08/18/2020] [Accepted: 08/18/2020] [Indexed: 02/07/2023]
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Adipocyte lipolysis: from molecular mechanisms of regulation to disease and therapeutics. Biochem J 2020; 477:985-1008. [PMID: 32168372 DOI: 10.1042/bcj20190468] [Citation(s) in RCA: 148] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 02/19/2020] [Accepted: 02/26/2020] [Indexed: 12/20/2022]
Abstract
Fatty acids (FAs) are stored safely in the form of triacylglycerol (TAG) in lipid droplet (LD) organelles by professional storage cells called adipocytes. These lipids are mobilized during adipocyte lipolysis, the fundamental process of hydrolyzing TAG to FAs for internal or systemic energy use. Our understanding of adipocyte lipolysis has greatly increased over the past 50 years from a basic enzymatic process to a dynamic regulatory one, involving the assembly and disassembly of protein complexes on the surface of LDs. These dynamic interactions are regulated by hormonal signals such as catecholamines and insulin which have opposing effects on lipolysis. Upon stimulation, patatin-like phospholipase domain containing 2 (PNPLA2)/adipocyte triglyceride lipase (ATGL), the rate limiting enzyme for TAG hydrolysis, is activated by the interaction with its co-activator, alpha/beta hydrolase domain-containing protein 5 (ABHD5), which is normally bound to perilipin 1 (PLIN1). Recently identified negative regulators of lipolysis include G0/G1 switch gene 2 (G0S2) and PNPLA3 which interact with PNPLA2 and ABHD5, respectively. This review focuses on the dynamic protein-protein interactions involved in lipolysis and discusses some of the emerging concepts in the control of lipolysis that include allosteric regulation and protein turnover. Furthermore, recent research demonstrates that many of the proteins involved in adipocyte lipolysis are multifunctional enzymes and that lipolysis can mediate homeostatic metabolic signals at both the cellular and whole-body level to promote inter-organ communication. Finally, adipocyte lipolysis is involved in various diseases such as cancer, type 2 diabetes and fatty liver disease, and targeting adipocyte lipolysis is of therapeutic interest.
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Baselli GA, Dongiovanni P, Rametta R, Meroni M, Pelusi S, Maggioni M, Badiali S, Pingitore P, Maurotti S, Montalcini T, Taliento AE, Prati D, Rossi G, Fracanzani AL, Mancina RM, Romeo S, Valenti L. Liver transcriptomics highlights interleukin-32 as novel NAFLD-related cytokine and candidate biomarker. Gut 2020; 69:1855-1866. [PMID: 32001554 PMCID: PMC7497582 DOI: 10.1136/gutjnl-2019-319226] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 12/05/2019] [Accepted: 12/22/2019] [Indexed: 12/17/2022]
Abstract
OBJECTIVE Efforts to manage non-alcoholic fatty liver disease (NAFLD) are limited by the incomplete understanding of the pathogenic mechanisms and the absence of accurate non-invasive biomarkers. The aim of this study was to identify novel NAFLD therapeutic targets andbiomarkers by conducting liver transcriptomic analysis in patients stratified by the presence of the PNPLA3 I148M genetic risk variant. DESIGN We sequenced the hepatic transcriptome of 125 obese individuals. 'Severe NAFLD' was defined as the presence of steatohepatitis, NAFLD activity score ≥4 or fibrosis stage ≥2. The circulating levels of the most upregulated transcript, interleukin-32 (IL32), were measured by ELISA. RESULTS Carriage of the PNPLA3 I148M variant correlated with the two major components of hepatic transcriptome variability and broadly influenced gene expression. In patients with severe NAFLD, there was an upregulation of inflammatory and lipid metabolism pathways. IL32 was the most robustly upregulated gene in the severe NAFLD group (adjusted p=1×10-6), and its expression correlated with steatosis severity, both in I148M variant carriers and non-carriers. In 77 severely obese, and in a replication cohort of 160 individuals evaluated at the hepatology service, circulating IL32 levels were associated with both NAFLD and severe NAFLD independently of aminotransferases (p<0.01 for both). A linear combination of IL32-ALT-AST showed a better performance than ALT-AST alone in NAFLD diagnosis (area under the curve=0.92 vs 0.81, p=5×10-5). CONCLUSION Hepatic IL32 is overexpressed in NAFLD, correlates with hepatic fat and liver damage, and is detectable in the circulation, where it is independently associated with the presence and severity of NAFLD.
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Affiliation(s)
- Guido Alessandro Baselli
- Department of Pathophysiology and Transplantation, Universita degli Studi di Milano, Milano, Lombardia, Italy,Translational Medicine, Department of Transfusion Medicine and Hematology, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milano, Lombardia, Italy
| | - Paola Dongiovanni
- General Medicine and Metabolic Diseases, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milano, Lombardia, Italy
| | - Raffaela Rametta
- General Medicine and Metabolic Diseases, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milano, Lombardia, Italy
| | - Marica Meroni
- General Medicine and Metabolic Diseases, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milano, Lombardia, Italy
| | - Serena Pelusi
- Department of Pathophysiology and Transplantation, Universita degli Studi di Milano, Milano, Lombardia, Italy,Translational Medicine, Department of Transfusion Medicine and Hematology, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milano, Lombardia, Italy
| | - Marco Maggioni
- Pathology, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milano, Lombardia, Italy
| | - Sara Badiali
- Surgery, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milano, Lombardia, Italy
| | - Piero Pingitore
- Clinical Nutrition Unit, Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, Catanzaro, Calabria, Italy
| | - Samantha Maurotti
- Clinical Nutrition Unit, Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, Catanzaro, Calabria, Italy
| | - Tiziana Montalcini
- Department of Clinical and Experimental Medicine, Nutrition Unit, Magna Graecia University of Catanzaro, Catanzaro, Calabria, Italy
| | - Alice Emma Taliento
- Translational Medicine, Department of Transfusion Medicine and Hematology, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milano, Lombardia, Italy
| | - Daniele Prati
- Translational Medicine, Department of Transfusion Medicine and Hematology, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milano, Lombardia, Italy
| | - Giorgio Rossi
- Department of Pathophysiology and Transplantation, Universita degli Studi di Milano, Milano, Lombardia, Italy,Liver Transplantation Center, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milano, Italy
| | - Anna Ludovica Fracanzani
- Department of Pathophysiology and Transplantation, Universita degli Studi di Milano, Milano, Lombardia, Italy,General Medicine and Metabolic Diseases, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milano, Lombardia, Italy
| | | | - Stefano Romeo
- Clinical Nutrition Unit, Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, Catanzaro, Calabria, Italy .,Sahlgrenska Center for Cardiovascular and Metabolic Research, Wallenberg Laboratory, Cardiology Department, University of Gothenburg, Goteborg, Sweden
| | - Luca Valenti
- Department of Pathophysiology and Transplantation, Universita degli Studi di Milano, Milano, Lombardia, Italy .,Translational Medicine, Department of Transfusion Medicine and Hematology, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milano, Lombardia, Italy
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Koo BK, Joo SK, Kim D, Lee S, Bae JM, Park JH, Kim JH, Chang MS, Kim W. Development and Validation of a Scoring System, Based on Genetic and Clinical Factors, to Determine Risk of Steatohepatitis in Asian Patients with Nonalcoholic Fatty Liver Disease. Clin Gastroenterol Hepatol 2020; 18:2592-2599.e10. [PMID: 32062042 DOI: 10.1016/j.cgh.2020.02.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 01/28/2020] [Accepted: 02/07/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS There are no biomarkers of nonalcoholic steatohepatitis (NASH) that are ready for routine clinical use. We investigated whether an analysis of PNPLA3 and TM6SF2 genotypes (rs738409 and rs58542926) can be used to identify patients with nonalcoholic fatty liver disease (NAFLD), with and without diabetes, who also have NASH. METHODS We collected data from the Boramae registry in Korea on 453 patients with biopsy-proven NAFLD with sufficient clinical data for calculating scores. Patients enrolled from February 2014 through March 2016 were assigned to cohort 1 (n = 302; discovery cohort) and patients enrolled thereafter were assigned to cohort 2 (n = 151; validation cohort). DNA samples were obtained from all participants and analyzed for the PNPLA3 rs738409 C>G, TM6SF2 rs58542926 C>T, SREBF2 rs133291 C>T, MBOAT7-TMC4 rs641738 C>T, and HSD17B13 rs72613567 adenine insertion (A-INS) polymorphisms. We used multivariable logistic regression analyses with stepwise backward selection to build a model to determine patients' risk for NASH (NASH PT) using the genotype and clinical data from cohort 1 and tested its accuracy in cohort 2. We used the receiver operating characteristic (ROC) curve to compare the diagnostic performances of the NASH PT and the NASH scoring systems. RESULTS We developed a NASH PT scoring system based on PNPLA3 and TM6SF2 genotypes, diabetes status, insulin resistance, and levels of aspartate aminotransferase and high-sensitivity C-reactive protein. NASH PT scores identified patients with NASH with an area under the ROC (AUROC) of 0.859 (95% CI, 0.817-0.901) in cohort 1. In cohort 2, NASH PT scores identified patients with NASH with an AUROC of 0.787 (95% CI, 0.715-0.860), which was significantly higher than the AUROC of the NASH score (AUROC, 0.729; 95% CI, 0.647-0.812; P = .007). The AUROC of the NASH PT score for detecting NASH in patients with NAFLD with diabetes was 0.835 (95% CI, 0.776-0.895) and in patients without diabetes was 0.809 (95% CI, 0.757-0.861). The negative predictive value of the NASH PT score <-0.785 for NASH in patients with NAFLD with diabetes reached 0.905. CONCLUSIONS We developed a scoring system, based on polymorphisms in PNPLA3 and TM6SF2 and clinical factors that identifies patients with NAFLD, with or without diabetes, who have NASH, with an AUROC value of 0.787. This system might help clinicians better identify NAFLD patients at risk for NASH.
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Affiliation(s)
- Bo Kyung Koo
- Division of Endocrinology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul Metropolitan Government Boramae Medical Center, Seoul, Korea
| | - Sae Kyung Joo
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul Metropolitan Government Boramae Medical Center, Seoul, Korea
| | - Donghee Kim
- Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, California
| | - Seonhwa Lee
- Department of Bio-convergence Engineering, Korea University, Seoul, Korea
| | - Jeong Mo Bae
- Department of Pathology, Seoul National University College of Medicine, Seoul Metropolitan Government Boramae Medical Center, Seoul, Korea
| | - Jeong Hwan Park
- Department of Pathology, Seoul National University College of Medicine, Seoul Metropolitan Government Boramae Medical Center, Seoul, Korea
| | - Jung Ho Kim
- Department of Pathology, Seoul National University College of Medicine, Seoul Metropolitan Government Boramae Medical Center, Seoul, Korea
| | - Mee Soo Chang
- Department of Pathology, Seoul National University College of Medicine, Seoul Metropolitan Government Boramae Medical Center, Seoul, Korea
| | - Won Kim
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul Metropolitan Government Boramae Medical Center, Seoul, Korea.
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Tang S, Zhang J, Mei TT, Guo HQ, Wei XH, Zhang WY, Liu YL, Liang S, Fan ZP, Ma LX, Lin W, Liu YR, Qiu LX, Yu HB. Association of PNPLA3 rs738409 G/C gene polymorphism with nonalcoholic fatty liver disease in children: a meta-analysis. BMC MEDICAL GENETICS 2020; 21:163. [PMID: 32811452 PMCID: PMC7433068 DOI: 10.1186/s12881-020-01098-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 07/30/2020] [Indexed: 02/06/2023]
Abstract
Background Nonalcoholic fatty liver disease (NAFLD) is one of the most common causes of chronic liver disease worldwide. Current studies have shown that PNPLA3 (Patatin-like phospholipase domain containing 3) rs738409 G/C gene polymorphism is associated with adult nonalcoholic fatty liver disease [1, 2].But there is no consensus on the relationship between PNPLA3 rs738409 G/C gene polymorphism and children NAFLD due to differences in population samples. To this end, a meta-analysis of published research is conducted to comprehensively assess the relationship between PNPLA3 gene polymorphism and NAFLD in children. Methods We searched MEDLINE, PubMed, EMBASE, and CENTRAL databases from inception to May 2019. Case-control studies assessing the relationship between PNPLA3 rs738409 G/C gene polymorphism with non-alcoholic fatty liver disease in children were selected according to inclusion and exclusion criteria. Random effects model was used to quantify the association between the PNPLA3 rs738409 G/C gene polymorphism and the susceptibility of children’s NAFLD. Fixed effects model was used to quantify the relationship between the PNPLA3 rs738409 G/C gene polymorphism and the severity of NAFLD in children. The Stata 12.0 software was employed for data analysis. Results A total of nine case-control studies were included in this meta-analysis containing data of 1173 children with NAFLD and 1792 healthy controls. Five studies compared NAFLD children and non-NAFLD healthy populations. Statistical analysis showed that PNPLA3 gene polymorphism was significantly associated with children’s NAFLD in the allele contrast, dominant, recessive and over dominant models (G vs C,OR = 3.343, 95% CI = 1.524–7.334; GG + GC vs CC,OR = 3.157, 95% CI = 1.446–6.892;GG vs GC + CC,OR = 5.692, 95% CI = 1.941–16.689; GG + CC vs GC,OR = 2.756, 95% CI = 1.729–4.392). Four case-control studies compared Children with nonalcoholic fatty liver (NAFL) and children with nonalcoholic steatohepatitis (NASH). The results showed that the PNPLA3 gene polymorphism was also significantly associated with the severity of NAFLD in children in recessive gene model (GG vs GC + CC,OR = 14.43, 95% CI = 5.985–34.997); The Egger’s test revealed no significant publication bias. Conclusions Meta-analysis showed that PNPLA3 gene polymorphism was significantly associated with susceptibility and severity of NAFLD in children.
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Affiliation(s)
- Shan Tang
- Department of Hepatitis C and Drug-Induced Liver Injury, Beijing YouAn Hospital, Capital Medical University, Beijing, 100069, China
| | - Jing Zhang
- Department of Hepatitis C and Drug-Induced Liver Injury, Beijing YouAn Hospital, Capital Medical University, Beijing, 100069, China
| | - Ting Ting Mei
- Department of Hepatitis C and Drug-Induced Liver Injury, Beijing YouAn Hospital, Capital Medical University, Beijing, 100069, China
| | - Hai Qing Guo
- Department of Hepatitis C and Drug-Induced Liver Injury, Beijing YouAn Hospital, Capital Medical University, Beijing, 100069, China
| | - Xin Huan Wei
- Department of Hepatitis C and Drug-Induced Liver Injury, Beijing YouAn Hospital, Capital Medical University, Beijing, 100069, China
| | - Wen Yan Zhang
- Department of Hepatitis C and Drug-Induced Liver Injury, Beijing YouAn Hospital, Capital Medical University, Beijing, 100069, China
| | - Ya Li Liu
- Department of Hepatitis C and Drug-Induced Liver Injury, Beijing YouAn Hospital, Capital Medical University, Beijing, 100069, China
| | - Shan Liang
- Department of Hepatitis C and Drug-Induced Liver Injury, Beijing YouAn Hospital, Capital Medical University, Beijing, 100069, China
| | - Zuo Peng Fan
- Department of Hepatitis C and Drug-Induced Liver Injury, Beijing YouAn Hospital, Capital Medical University, Beijing, 100069, China
| | - Li Xia Ma
- Department of Hepatitis C and Drug-Induced Liver Injury, Beijing YouAn Hospital, Capital Medical University, Beijing, 100069, China
| | - Wei Lin
- Department of Hepatitis C and Drug-Induced Liver Injury, Beijing YouAn Hospital, Capital Medical University, Beijing, 100069, China
| | - Yi Rong Liu
- Department of Hepatitis C and Drug-Induced Liver Injury, Beijing YouAn Hospital, Capital Medical University, Beijing, 100069, China
| | - Li Xia Qiu
- Department of Hepatitis C and Drug-Induced Liver Injury, Beijing YouAn Hospital, Capital Medical University, Beijing, 100069, China
| | - Hai Bin Yu
- Department of Hepatitis C and Drug-Induced Liver Injury, Beijing YouAn Hospital, Capital Medical University, Beijing, 100069, China.
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31
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Seeßle J, Gan-Schreier H, Kirchner M, Stremmel W, Chamulitrat W, Merle U. Plasma Lipidome, PNPLA3 polymorphism and hepatic steatosis in hereditary hemochromatosis. BMC Gastroenterol 2020; 20:230. [PMID: 32680469 PMCID: PMC7368730 DOI: 10.1186/s12876-020-01282-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Accepted: 04/22/2020] [Indexed: 12/20/2022] Open
Abstract
Background Hereditary hemochromatosis (HH) is an autosomal recessive genetic disorder with increased intestinal iron absorption and therefore iron Overload. iron overload leads to increased levels of toxic non-transferrin bound iron which results in oxidative stress and lipid peroxidation. The impact of iron on lipid metabolism is so far not fully understood. The aim of this study was to investigate lipid metabolism including lipoproteins (HDL, LDL), neutral (triglycerides, cholesterol) and polar lipids (sphingo- and phospholipids), and PNPLA3 polymorphism (rs738409/I148M) in HH. Methods We conducted a cohort study of 54 subjects with HH and 20 healthy subjects. Patients were analyzed for their iron status including iron, ferritin, transferrin and transferrin saturation and serum lipid profile on a routine follow-up examination. Results HH group showed significantly lower serum phosphatidylcholine (PC) and significantly higher phosphatidylethanolamine (PE) compared to healthy control group. The ratio of PC/PE was clearly lower in HH group indicating a shift from PC to PE. Triglycerides were significantly higher in HH group. No differences were seen for HDL, LDL and cholesterol. Hepatic steatosis was significantly more frequent in HH. PNPLA3 polymorphism (CC vs. CG/GG) did not reveal any significant correlation with iron and lipid parameters including neutral and polar lipids, grade of steatosis and fibrosis. Conclusion Our study strengthens the hypothesis of altered lipid metabolism in HH and susceptibility to nonalcoholic fatty liver disease. Disturbed phospholipid metabolism may represent an important factor in pathogenesis of hepatic steatosis in HH.
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Affiliation(s)
- Jessica Seeßle
- Department of Gastroenterology, University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
| | - Hongying Gan-Schreier
- Department of Gastroenterology, University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
| | - Marietta Kirchner
- Institute of Medical Biometry and Informatics, University Hospital Heidelberg, Heidelberg, Germany
| | - Wolfgang Stremmel
- Department of Gastroenterology, University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
| | - Walee Chamulitrat
- Department of Gastroenterology, University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
| | - Uta Merle
- Department of Gastroenterology, University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany.
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32
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Carlsson B, Lindén D, Brolén G, Liljeblad M, Bjursell M, Romeo S, Loomba R. Review article: the emerging role of genetics in precision medicine for patients with non-alcoholic steatohepatitis. Aliment Pharmacol Ther 2020; 51:1305-1320. [PMID: 32383295 PMCID: PMC7318322 DOI: 10.1111/apt.15738] [Citation(s) in RCA: 125] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 01/13/2020] [Accepted: 03/29/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND Non-alcoholic steatohepatitis (NASH) is a severe form of non-alcoholic fatty liver disease (NAFLD) characterised by liver fat accumulation, inflammation and progressive fibrosis. Emerging data indicate that genetic susceptibility increases risks of NAFLD, NASH and NASH-related cirrhosis. AIMS To review NASH genetics and discuss the potential for precision medicine approaches to treatment. METHOD PubMed search and inclusion of relevant literature. RESULTS Single-nucleotide polymorphisms in PNPLA3, TM6SF2, GCKR, MBOAT7 and HSD17B13 are clearly associated with NASH development or progression. These genetic variants are common and have moderate-to-large effect sizes for development of NAFLD, NASH and hepatocellular carcinoma (HCC). The genes play roles in lipid remodelling in lipid droplets, hepatic very low-density lipoprotein (VLDL) secretion and de novo lipogenesis. The PNPLA3 I148M variant (rs738409) has large effects, with approximately twofold increased odds of NAFLD and threefold increased odds of NASH and HCC per allele. Obesity interacts with PNPLA3 I148M to elevate liver fat content and increase rates of NASH. Although the isoleucine-to-methionine substitution at amino acid position 148 of the PNPLA3 enzyme inactivates its lipid remodelling activity, the effect of PNPLA3 I148M results from trans-repression of another lipase (ATGL/PNPLA2) by sequestration of a shared cofactor (CGI-58/ABHD5), leading to decreased hepatic lipolysis and VLDL secretion. In homozygous Pnpla3 I148M knock-in rodent models of NAFLD, targeted PNPLA3 mRNA knockdown reduces hepatic steatosis, inflammation and fibrosis. CONCLUSION The emerging genetic and molecular understanding of NASH paves the way for novel interventions, including precision medicines that can modulate the activity of specific genes associated with NASH.
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Affiliation(s)
- Björn Carlsson
- Research and Early DevelopmentCardiovascular, Renal and MetabolismBioPharmaceuticals R&DAstraZenecaGothenburgSweden
| | - Daniel Lindén
- Research and Early DevelopmentCardiovascular, Renal and MetabolismBioPharmaceuticals R&DAstraZenecaGothenburgSweden,Division of EndocrinologyDepartment of Neuroscience and PhysiologySahlgrenska AcademyUniversity of GothenburgGothenburgSweden
| | - Gabriella Brolén
- Precision MedicineCardiovascular, Renal and MetabolismR&DAstraZenecaGothenburgSweden
| | - Mathias Liljeblad
- Research and Early DevelopmentCardiovascular, Renal and MetabolismBioPharmaceuticals R&DAstraZenecaGothenburgSweden
| | - Mikael Bjursell
- Research and Early DevelopmentCardiovascular, Renal and MetabolismBioPharmaceuticals R&DAstraZenecaGothenburgSweden
| | - Stefano Romeo
- Department of Molecular and Clinical MedicineUniversity of GothenburgGothenburgSweden,Clinical Nutrition UnitDepartment of Medical and Surgical SciencesMagna Graecia UniversityCatanzaroItaly,Cardiology DepartmentSahlgrenska University HospitalGothenburgSweden
| | - Rohit Loomba
- NAFLD Research CenterDivision of GastroenterologyUniversity of California San DiegoSan DiegoCAUSA
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Matsuzaka T, Kuba M, Koyasu S, Yamamoto Y, Motomura K, Arulmozhiraja S, Ohno H, Sharma R, Shimura T, Okajima Y, Han SI, Aita Y, Mizunoe Y, Osaki Y, Iwasaki H, Yatoh S, Suzuki H, Sone H, Takeuchi Y, Yahagi N, Miyamoto T, Sekiya M, Nakagawa Y, Ema M, Takahashi S, Tokiwa H, Shimano H. Hepatocyte ELOVL Fatty Acid Elongase 6 Determines Ceramide Acyl-Chain Length and Hepatic Insulin Sensitivity in Mice. Hepatology 2020; 71:1609-1625. [PMID: 31529722 DOI: 10.1002/hep.30953] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 09/09/2019] [Indexed: 12/19/2022]
Abstract
BACKGROUND AND AIMS Dysfunctional hepatic lipid metabolism is a cause of nonalcoholic fatty liver disease (NAFLD), the most common chronic liver disorder worldwide, and is closely associated with insulin resistance and type 2 diabetes. ELOVL fatty acid elongase 6 (Elovl6) is responsible for converting C16 saturated and monounsaturated fatty acids (FAs) into C18 species. We have previously shown that Elovl6 contributes to obesity-induced insulin resistance by modifying hepatic C16/C18-related FA composition. APPROACH AND RESULTS To define the precise molecular mechanism by which hepatic Elovl6 affects energy homeostasis and metabolic disease, we generated liver-specific Elovl6 knockout (LKO) mice. Unexpectedly, LKO mice were not protected from high-fat diet-induced insulin resistance. Instead, LKO mice exhibited higher insulin sensitivity than controls when consuming a high-sucrose diet (HSD), which induces lipogenesis. Hepatic patatin-like phospholipase domain-containing protein 3 (Pnpla3) expression was down-regulated in LKO mice, and adenoviral Pnpla3 restoration reversed the enhancement in insulin sensitivity in HSD-fed LKO mice. Lipidomic analyses showed that the hepatic ceramide(d18:1/18:0) content was lower in LKO mice, which may explain the effect on insulin sensitivity. Ceramide(d18:1/18:0) enhances protein phosphatase 2A (PP2A) activity by interfering with the binding of PP2A to inhibitor 2 of PP2A, leading to Akt dephosphorylation. Its production involves the formation of an Elovl6-ceramide synthase 4 (CerS4) complex in the endoplasmic reticulum and a Pnpla3-CerS4 complex on lipid droplets. Consistent with this, liver-specific Elovl6 deletion in ob/ob mice reduced both hepatic ceramide(d18:1/18:0) and PP2A activity and ameliorated insulin resistance. CONCLUSIONS Our study demonstrates the key role of hepatic Elovl6 in the regulation of the acyl-chain composition of ceramide and that C18:0-ceramide is a potent regulator of hepatic insulin signaling linked to Pnpla3-mediated NAFLD.
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Affiliation(s)
- Takashi Matsuzaka
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan.,Transborder Medical Research Center, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Motoko Kuba
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Saori Koyasu
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Yuta Yamamoto
- Department of Chemistry, Rikkyo University, Toshima, Tokyo, Japan
| | - Kaori Motomura
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | | | - Hiroshi Ohno
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Rahul Sharma
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Takuya Shimura
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Yuka Okajima
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Song-Iee Han
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Yuichi Aita
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Yuhei Mizunoe
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Yoshinori Osaki
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Hitoshi Iwasaki
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Shigeru Yatoh
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Hiroaki Suzuki
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Hirohito Sone
- Department of Internal Medicine, Faculty of Medicine, Niigata University, Niigata, Japan
| | - Yoshinori Takeuchi
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Naoya Yahagi
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Takafumi Miyamoto
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan.,Transborder Medical Research Center, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Motohiro Sekiya
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Yoshimi Nakagawa
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan.,International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Masatsugu Ema
- Department of Stem Cells and Human Disease Models, Research Center for Animal Life Science, Shiga University of Medical Science, Seta, Tsukinowa-cho, Otsu, Shiga, Japan
| | - Satoru Takahashi
- Transborder Medical Research Center, University of Tsukuba, Tsukuba, Ibaraki, Japan.,International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan.,Department of Anatomy and Embryology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan.,Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, Ibaraki, Japan.,Laboratory Animal Resource Center, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Hiroaki Tokiwa
- Department of Chemistry, Rikkyo University, Toshima, Tokyo, Japan
| | - Hitoshi Shimano
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan.,International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan.,Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, Ibaraki, Japan.,AMED-CREST, Japan Agency for Medical Research and Development, Chiyoda-ku, Tokyo, Japan
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Bruschi FV, Tardelli M, Herac M, Claudel T, Trauner M. Metabolic regulation of hepatic PNPLA3 expression and severity of liver fibrosis in patients with NASH. Liver Int 2020; 40:1098-1110. [PMID: 32043752 PMCID: PMC7318357 DOI: 10.1111/liv.14402] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 01/31/2020] [Accepted: 02/03/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND AIMS The genetic PNPLA3 polymorphism I148M has been extensively associated with higher risk for development and progression of NAFLD towards NASH. METHODS PNPLA3 and α-SMA expression were quantified in liver biopsies collected from NASH patients (n = 26) with different fibrosis stages and PNPLA3 genotypes. To study the potential mechanisms driving PNPLA3 expression during NASH progression towards fibrosis, hepatocytes and hepatic stellate cells (HSCs) were cultivated in low and high glucose medium. Moreover, hepatocytes were treated with increasing concentrations of palmitic acid alone or in combination with glucose. Conditioned media were collected from challenged hepatocytes to stimulate HSCs. RESULTS Tissue expression of PNPLA3 was significantly enhanced in biopsies of patients carrying the I148M polymorphism compared to wild type (WT). In NASH biopsies, PNPLA3 significantly correlated with fibrosis stage and α-SMA levels independently of PNPLA3 genotype. In line, PNPLA3 expression was higher in α-SMA positive cells. Low glucose increased PNPLA3 in HSCs, whereas high glucose induced PNPLA3 and de-novo lipogenesis-related genes expression in hepatocytes. Palmitic acid induced fat accumulation and cell stress markers in hepatocytes, which could be counteracted by oleic acid. Conditioned media collected from lipotoxic challenged hepatocytes markedly induced PNPLA3 mRNA and protein levels, fibrogenic and autophagic markers and promoted migration in HSCs. Notably, conditioned media collected from hepatocytes cultivated with both glucose and palmitic acid exacerbated HSCs migration, PNPLA3 and fibrogenic gene expression, promoting release of cytokines from HSCs. CONCLUSIONS Collectively, our observations uncover the diverse metabolic regulation of PNPLA3 among different hepatic cell populations and support its relation to fibrosis progression.
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Affiliation(s)
- Francesca V. Bruschi
- Hans Popper Laboratory of Molecular HepatologyDivision of Gastroenterology and HepatologyInternal Medicine IIIMedical University of ViennaViennaAustria
| | - Matteo Tardelli
- Hans Popper Laboratory of Molecular HepatologyDivision of Gastroenterology and HepatologyInternal Medicine IIIMedical University of ViennaViennaAustria,Division of Gastroenterology and HepatologyJoan and Sanford I. Weill Cornell Department of MedicineWeill Cornell Medical CollegeNew YorkNYUSA
| | - Merima Herac
- Clinical Institute of PathologyMedical University of ViennaViennaAustria
| | - Thierry Claudel
- Hans Popper Laboratory of Molecular HepatologyDivision of Gastroenterology and HepatologyInternal Medicine IIIMedical University of ViennaViennaAustria
| | - Michael Trauner
- Hans Popper Laboratory of Molecular HepatologyDivision of Gastroenterology and HepatologyInternal Medicine IIIMedical University of ViennaViennaAustria
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35
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Abstract
Copper accumulation and deficiency are reciprocally connected to lipid metabolism. In Wilson disease (WD), which is caused by a genetic loss of function of the copper-transporting P-type ATPase beta, copper accumulates mainly in the liver and lipid metabolism is dysregulated. The underlying mechanisms linking copper and lipid metabolism in WD are not clear. Copper may impair metabolic machinery by direct binding to protein and lipid structures or by generating reactive oxygen species with consequent damage to cellular organelles vital to energy metabolism. In the liver, copper overload results in mitochondrial impairment, down-regulation of lipid metabolism, and the development of steatosis with an etiology not fully elucidated. Little is known regarding the effect of copper overload on extrahepatic energy homeostasis. This review aims to discuss alterations in hepatic energy metabolism associated with WD, highlights potential mechanisms involved in the development of hepatic and systemic dysregulation of lipid metabolism, and reviews current knowledge on the effects of copper overload on extrahepatic energy metabolism.
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Affiliation(s)
- Tagreed A. Mazi
- Department of Nutrition, University of California Davis, Davis, CA, USA,Department of Community Health Sciences, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Noreene M. Shibata
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, University of California Davis, Sacramento, CA, USA
| | - Valentina Medici
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, University of California Davis, Sacramento, CA, USA,Corresponding author. (V. Medici)
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36
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Yuan S, Liu H, Yuan D, Xu J, Chen Y, Xu X, Xu F, Liang H. PNPLA3 I148M mediates the regulatory effect of NF-kB on inflammation in PA-treated HepG2 cells. J Cell Mol Med 2019; 24:1541-1552. [PMID: 31793207 PMCID: PMC6991629 DOI: 10.1111/jcmm.14839] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 09/19/2019] [Accepted: 10/19/2019] [Indexed: 12/17/2022] Open
Abstract
Both PNPLA3 I148M and hepatic inflammation are associated with nonalcoholic fatty liver disease (NAFLD) progression. This study aimed to elucidate whether PNPLA3 I148M is involved in NF‐kB‐related inflammation regulation in NAFLD. HepG2 cells homozygous for the PNPLA3 I148M mutation were used. The human PNPLA3 promoter sequence was screened for NF‐kB binding sites using the MATCH and PATCH tools. NF‐kB‐mediated transcriptional regulation of the PNPLA3 gene was assessed by luciferase reporter assay, EMSA and ChIP‐qPCR. Wild‐type (I148I) and mutant (M148M) PNPLA3 were overexpressed using stable lentivirus‐mediated transfection. The pCMV vector and siRNA were transiently transfected into cells to direct NF‐kB overexpression and PNPLA3 silencing, respectively. A putative NF‐kB binding site in the human PNPLA3 promoter was shown to be necessary for basal and NF‐kB‐driven transcriptional activation of PNPLA3 and protein/DNA complex formation. Supershift analysis demonstrated a protein/DNA complex specifically containing the NF‐kB p65 and p50 subunits. ChIP‐qPCR confirmed the endogenous binding of NF‐kB to the human PNPLA3 promoter in response to NF‐kB overexpression and palmitic acid (PA) challenge. The silencing of PNPLA3 blocked the overexpression of NF‐kB or PA‐induced TNF‐α up‐regulation. Moreover, mutant PNPLA3 overexpression prevented NF‐kB inhibitor–induced down‐regulation of TNF‐α expression in PA‐treated HepG2 cells. Finally, the overexpression of mutant but not wild‐type PNPLA3 increased TNF‐α expression and activated the ER stress–mediated and NF‐kB‐independent inflammatory IRE‐1α/JNK/c‐Jun pathway. Human PNPLA3 was shown to be a target of NF‐kB, and PNPLA3 I148M mediated the regulatory effect of NF‐kB on inflammation in PA‐treated HepG2 cells, most likely via the IRE‐1α/JNK/c‐Jun ER stress pathway.
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Affiliation(s)
- Shuhua Yuan
- Department of Endocrinology and Metabolism, Guangdong Provincial Key Laboratory of Diabetology, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.,Department of Endocrinology, Guangzhou Panyu Central Hospital, Guangzhou, China
| | - Hongxia Liu
- Department of Endocrinology and Metabolism, Guangdong Provincial Key Laboratory of Diabetology, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Ding Yuan
- Department of Endocrinology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Jing Xu
- Department of Endocrinology and Metabolism, The Affiliated Hospital of Guizhou Medical University, Guiyang, China
| | - Yunzhi Chen
- Department of Endocrinology and Metabolism, Guangdong Provincial Key Laboratory of Diabetology, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Xiao Xu
- Department of Endocrinology and Metabolism, Guangdong Provincial Key Laboratory of Diabetology, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Fen Xu
- Department of Endocrinology and Metabolism, Guangdong Provincial Key Laboratory of Diabetology, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Hua Liang
- Department of Endocrinology and Metabolism, Guangdong Provincial Key Laboratory of Diabetology, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
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37
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Abstract
Fatty liver disease (FLD) affects more than one-third of the population in the western world and an increasing number of children in the United States. It is a leading cause of obesity and liver transplantation. Mechanistic insights into the causes of FLD are urgently needed since no therapeutic intervention has proven to be effective. A sequence variation in patatin like phospholipase domain-containing protein 3 (PNPLA3), rs 738409, is strongly associated with the progression of fatty liver disease. The resulting mutant causes a substitution of isoleucine to methionine at position 148. The underlying mechanism of this disease remains unsolved although several studies have illuminated key insights into its pathogenesis. This review highlights the progress in our understanding of PNPLA3 function in lipid droplet dynamics and explores possible therapeutic interventions to ameliorate this human health hazard.
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Affiliation(s)
- Soumik Basu Ray
- Eugene McDermott Center for Human Growth and Development, Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA
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38
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Iruarrizaga-Lejarreta M, Arretxe E, Alonso C. Using metabolomics to develop precision medicine strategies to treat nonalcoholic steatohepatitis. EXPERT REVIEW OF PRECISION MEDICINE AND DRUG DEVELOPMENT 2019. [DOI: 10.1080/23808993.2019.1685379] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
| | - Enara Arretxe
- OWL Metabolomics, Parque Tecnológico de Bizkaia, Derio, Spain
| | - Cristina Alonso
- OWL Metabolomics, Parque Tecnológico de Bizkaia, Derio, Spain
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39
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El Saeed KM, Ahmed OA, Khalifa MO, Fahmy EM. Detection of patatin-like phospholipase domain-containing protein 3 in nonalcoholic fatty liver disease among egyptian patients. THE EGYPTIAN JOURNAL OF INTERNAL MEDICINE 2019; 31:273-280. [DOI: 10.4103/ejim.ejim_43_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 07/04/2018] [Indexed: 11/04/2022] Open
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40
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Luukkonen PK, Nick A, Hölttä-Vuori M, Thiele C, Isokuortti E, Lallukka-Brück S, Zhou Y, Hakkarainen A, Lundbom N, Peltonen M, Orho-Melander M, Orešič M, Hyötyläinen T, Hodson L, Ikonen E, Yki-Järvinen H. Human PNPLA3-I148M variant increases hepatic retention of polyunsaturated fatty acids. JCI Insight 2019; 4:127902. [PMID: 31434800 PMCID: PMC6777808 DOI: 10.1172/jci.insight.127902] [Citation(s) in RCA: 116] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 07/16/2019] [Indexed: 12/14/2022] Open
Abstract
The common patatin-like phospholipase domain-containing protein 3 (PNPLA3) variant I148M predisposes to nonalcoholic liver disease but not its metabolic sequelae. We compared the handling of labeled polyunsaturated fatty acids (PUFAs) and saturated fatty acids (SFA) in vivo in humans and in cells harboring different PNPLA3 genotypes. In 148M homozygous individuals, triglycerides (TGs) in very low-density lipoproteins (VLDL) were depleted of PUFAs both under fasting and postprandial conditions compared with 148I homozygotes, and the PUFA/SFA ratio in VLDL-TGs was lower relative to the chylomicron precursor pool. In human PNPLA3-148M and PNPLA3-KO cells, PUFA but not SFA incorporation into TGs was increased at the expense of phosphatidylcholines, and under lipolytic conditions, PUFA-containing diacylglycerols (DAGs) accumulated compared with PNPLA3-148I cells. Polyunsaturated TGs were increased, while phosphatidylcholines (PCs) were decreased in the human liver in 148M homozygous individuals as compared with 148I homozygotes. We conclude that human PNPLA3-I148M is a loss-of-function allele that remodels liver TGs in a polyunsaturated direction by impairing hydrolysis/transacylation of PUFAs from DAGs to feed phosphatidylcholine synthesis.
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Affiliation(s)
- Panu K. Luukkonen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
- Department of Medicine, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Auli Nick
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
- Faculty of Medicine, Department of Anatomy, University of Helsinki, Helsinki, Finland
| | - Maarit Hölttä-Vuori
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
- Faculty of Medicine, Department of Anatomy, University of Helsinki, Helsinki, Finland
| | | | - Elina Isokuortti
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
- Department of Medicine, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Susanna Lallukka-Brück
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
- Department of Medicine, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - You Zhou
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
- Systems Immunity Research Institute, Cardiff University, Cardiff, United Kingdom
- Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff, United Kingdom
| | - Antti Hakkarainen
- Department of Radiology, HUS Medical Imaging Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland
| | - Nina Lundbom
- Department of Radiology, HUS Medical Imaging Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Markku Peltonen
- Department of Public Health Solutions, National Institute for Health and Welfare, Helsinki, Finland
| | | | - Matej Orešič
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku, Finland
- School of Medical Sciences and
| | | | - Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, United Kingdom
| | - Elina Ikonen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
- Faculty of Medicine, Department of Anatomy, University of Helsinki, Helsinki, Finland
| | - Hannele Yki-Järvinen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
- Department of Medicine, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
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41
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Xia MF, Bian H, Gao X. NAFLD and Diabetes: Two Sides of the Same Coin? Rationale for Gene-Based Personalized NAFLD Treatment. Front Pharmacol 2019; 10:877. [PMID: 31447675 PMCID: PMC6691129 DOI: 10.3389/fphar.2019.00877] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 07/10/2019] [Indexed: 12/14/2022] Open
Abstract
The prevalence of non-alcoholic fatty liver disease (NAFLD) has been increasing rapidly and at the forefront of worldwide concern. Characterized by excessive fat accumulation in the liver, NAFLD regularly coexists with metabolic disorders, including type 2 diabetes, obesity, and cardiovascular disease. It has been well established that the presence of NAFLD increases the incidence of type 2 diabetes, while diabetes aggravates NAFLD to more severe forms of steatohepatitis, cirrhosis, and hepatocellular carcinoma. However, recent progress on the genotype/phenotype relationships in NAFLD patients indicates the development of NAFLD with a relative conservation of glucose metabolism in individuals with specific gene variants, such as the patatin-like phospholipase domain-containing 3 (PNPLA3) and transmembrane 6 superfamily member 2 protein (TM6SF2) variants. This review will focus on the clinical and pathophysiological connections between NAFLD and type 2 diabetes and will also discuss a disproportionate progression of NAFLD and diabetes, and the different responses to lifestyle and drug intervention in NAFLD patients with specific gene variants that may give insight into personalized treatment for NAFLD.
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Affiliation(s)
- Ming-Feng Xia
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China
- Fudan Institute for Metabolic Diseases, Fudan University, Shanghai, China
| | - Hua Bian
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China
- Fudan Institute for Metabolic Diseases, Fudan University, Shanghai, China
| | - Xin Gao
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China
- Fudan Institute for Metabolic Diseases, Fudan University, Shanghai, China
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42
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Mato JM, Alonso C, Noureddin M, Lu SC. Biomarkers and subtypes of deranged lipid metabolism in non-alcoholic fatty liver disease. World J Gastroenterol 2019; 25:3009-3020. [PMID: 31293337 PMCID: PMC6603806 DOI: 10.3748/wjg.v25.i24.3009] [Citation(s) in RCA: 140] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 05/06/2019] [Accepted: 05/18/2019] [Indexed: 02/06/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is a heterogeneous and complex disease that is imprecisely diagnosed by liver biopsy. NAFLD covers a spectrum that ranges from simple steatosis, nonalcoholic steatohepatitis (NASH) with varying degrees of fibrosis, to cirrhosis, which is a major risk factor for hepatocellular carcinoma. Lifestyle and eating habit changes during the last century have made NAFLD the most common liver disease linked to obesity, type 2 diabetes mellitus and dyslipidemia, with a global prevalence of 25%. NAFLD arises when the uptake of fatty acids (FA) and triglycerides (TG) from circulation and de novo lipogenesis saturate the rate of FA β-oxidation and very-low density lipoprotein (VLDL)-TG export. Deranged lipid metabolism is also associated with NAFLD progression from steatosis to NASH, and therefore, alterations in liver and serum lipidomic signatures are good indicators of the disease’s development and progression. This review focuses on the importance of the classification of NAFLD patients into different subtypes, corresponding to the main alteration(s) in the major pathways that regulate FA homeostasis leading, in each case, to the initiation and progression of NASH. This concept also supports the targeted intervention as a key approach to maximize therapeutic efficacy and opens the door to the development of precise NASH treatments.
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Affiliation(s)
- José M Mato
- CIC bioGUNE, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (Ciberehd), Technology Park of Bizkaia, Derio 48160, Bizkaia, Spain
| | - Cristina Alonso
- OWL Metabolomics, Technology Park of Bizkaia, Derio 48160, Bizkaia, Spain
| | - Mazen Noureddin
- Division of Digestive and Liver Diseases, Comprehensive Transplant Center, Cedars-Sinai Medical Center, Los Angeles, CA 90048, United States
| | - Shelly C Lu
- Division of Digestive and Liver Diseases, Comprehensive Transplant Center, Cedars-Sinai Medical Center, Los Angeles, CA 90048, United States
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43
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Wang Y, Kory N, BasuRay S, Cohen JC, Hobbs HH. PNPLA3, CGI-58, and Inhibition of Hepatic Triglyceride Hydrolysis in Mice. Hepatology 2019; 69:2427-2441. [PMID: 30802989 PMCID: PMC6563103 DOI: 10.1002/hep.30583] [Citation(s) in RCA: 134] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Accepted: 02/16/2019] [Indexed: 12/12/2022]
Abstract
A variant (148M) in patatin-like phospholipase domain-containing protein 3 (PNPLA3) is a major risk factor for fatty liver disease. Despite its clinical importance, the pathogenic mechanism linking the variant to liver disease remains poorly defined. Previously, we showed that PNPLA3(148M) accumulates to high levels on hepatic lipid droplets (LDs). Here we examined the effect of that accumulation on triglyceride (TG) hydrolysis by adipose triglyceride lipase (ATGL), the major lipase in the liver. As expected, overexpression of ATGL in cultured hepatoma (HuH-7) cells depleted the cells of LDs, but unexpectedly, co-expression of PNPLA3(wild type [WT] or 148M) with ATGL inhibited that depletion. The inhibitory effect of PNPLA3 was not caused by the displacement of ATGL from LDs. We tested the hypothesis that PNPLA3 interferes with ATGL activity by interacting with its cofactor, comparative gene identification-58 (CGI-58). Evidence supporting such an interaction came from two findings. First, co-expression of PNPLA3 and CGI-58 resulted in LD depletion in cultured cells, but expression of PNPLA3 alone did not. Second, PNPLA3 failed to localize to hepatic LDs in liver-specific Cgi-58 knockout (KO) mice. Moreover, overexpression of PNPLA3(148M) increased hepatic TG levels in WT, but not in Cgi-58 KO mice. Thus, the pro-steatotic effects of PNPLA3 required the presence of CGI-58. Co-immunoprecipitation and pulldown experiments in livers of mice and in vitro using purified proteins provided evidence that PNPLA3 and CGI-58 can interact directly. Conclusion: Taken together, these findings are consistent with a model in which PNPLA3(148M) promotes steatosis by CGI-58-dependent inhibition of ATGL on LDs.
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Affiliation(s)
- Yang Wang
- Department of Molecular GeneticsUniversity of Texas Southwestern Medical CenterDallasTX
| | - Nora Kory
- Department of Molecular GeneticsUniversity of Texas Southwestern Medical CenterDallasTX
| | - Soumik BasuRay
- Department of Molecular GeneticsUniversity of Texas Southwestern Medical CenterDallasTX
| | - Jonathan C. Cohen
- Department of Internal MedicineUniversity of Texas Southwestern Medical CenterDallasTX,The Center for Human NutritionUniversity of Texas Southwestern Medical CenterDallas TX
| | - Helen H. Hobbs
- Department of Molecular GeneticsUniversity of Texas Southwestern Medical CenterDallasTX,Department of Internal MedicineUniversity of Texas Southwestern Medical CenterDallasTX,Howard Hughes Medical InstituteUniversity of Texas Southwestern Medical CenterDallasTX
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44
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Pastore M, Grimaudo S, Pipitone RM, Lori G, Raggi C, Petta S, Marra F. Role of Myeloid-Epithelial-Reproductive Tyrosine Kinase and Macrophage Polarization in the Progression of Atherosclerotic Lesions Associated With Nonalcoholic Fatty Liver Disease. Front Pharmacol 2019; 10:604. [PMID: 31191323 PMCID: PMC6548874 DOI: 10.3389/fphar.2019.00604] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 05/14/2019] [Indexed: 12/13/2022] Open
Abstract
Recent lines of evidence highlight the involvement of myeloid-epithelial-reproductive tyrosine kinase (MerTK) in metabolic disease associated with liver damage. MerTK is mainly expressed in anti-inflammatory M2 macrophages where it mediates transcriptional changes including suppression of proinflammatory cytokines and enhancement of inflammatory repressors. MerTK is regulated by metabolic pathways through nuclear sensors including LXRs, PPARs, and RXRs, in response to apoptotic bodies or to other sources of cholesterol. Nonalcoholic fatty liver disease (NAFLD) is one of the most serious public health problems worldwide. It is a clinicopathological syndrome closely related to obesity, insulin resistance, and oxidative stress. It includes a spectrum of conditions ranging from simple steatosis, characterized by hepatic fat accumulation with or without inflammation, to nonalcoholic steatohepatitis (NASH), defined by hepatic fat deposition with hepatocellular damage, inflammation, and accumulating fibrosis. Several studies support an association between NAFLD and the incidence of cardiovascular diseases including atherosclerosis, a major cause of death worldwide. This pathological condition consists in a chronic and progressive inflammatory process in the intimal layer of large- and medium-sized arteries. The complications of advanced atherosclerosis include chronic or acute ischemic damage in the tissue perfused by the affected artery, leading to cellular death. By identifying specific targets influencing lipid metabolism and cardiovascular-related diseases, the present review highlights the role of MerTK in NAFLD-associated atherosclerotic lesions as a potential innovative therapeutic target. Therapeutic advantages might derive from the use of compounds selective for nuclear receptors targeting PPARs rather than LXRs regulating macrophage lipid metabolism and macrophage mediated inflammation, by favoring the expression of MerTK, which mediates an immunoregulatory action with a reduction in inflammation and in atherosclerosis.
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Affiliation(s)
- Mirella Pastore
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Stefania Grimaudo
- Section of Gastroenterology and Hepatology, PROMISE, University of Palermo, Palermo, Italy
| | - Rosaria Maria Pipitone
- Section of Gastroenterology and Hepatology, PROMISE, University of Palermo, Palermo, Italy
| | - Giulia Lori
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Chiara Raggi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy.,Humanitas Clinical and Research Center, Rozzano, Italy
| | - Salvatore Petta
- Section of Gastroenterology and Hepatology, PROMISE, University of Palermo, Palermo, Italy
| | - Fabio Marra
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
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45
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Green CJ, Parry SA, Gunn PJ, Ceresa CDL, Rosqvist F, Piché ME, Hodson L. Studying non-alcoholic fatty liver disease: the ins and outs of in vivo, ex vivo and in vitro human models. Horm Mol Biol Clin Investig 2018; 41:/j/hmbci.ahead-of-print/hmbci-2018-0038/hmbci-2018-0038.xml. [PMID: 30098284 DOI: 10.1515/hmbci-2018-0038] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 06/22/2018] [Indexed: 02/07/2023]
Abstract
The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing. Determining the pathogenesis and pathophysiology of human NAFLD will allow for evidence-based prevention strategies, and more targeted mechanistic investigations. Various in vivo, ex situ and in vitro models may be utilised to study NAFLD; but all come with their own specific caveats. Here, we review the human-based models and discuss their advantages and limitations in regards to studying the development and progression of NAFLD. Overall, in vivo whole-body human studies are advantageous in that they allow for investigation within the physiological setting, however, limited accessibility to the liver makes direct investigations challenging. Non-invasive imaging techniques are able to somewhat overcome this challenge, whilst the use of stable-isotope tracers enables mechanistic insight to be obtained. Recent technological advances (i.e. normothermic machine perfusion) have opened new opportunities to investigate whole-organ metabolism, thus ex situ livers can be investigated directly. Therefore, investigations that cannot be performed in vivo in humans have the potential to be undertaken. In vitro models offer the ability to perform investigations at a cellular level, aiding in elucidating the molecular mechanisms of NAFLD. However, a number of current models do not closely resemble the human condition and work is ongoing to optimise culturing parameters in order to recapitulate this. In summary, no single model currently provides insight into the development, pathophysiology and progression across the NAFLD spectrum, each experimental model has limitations, which need to be taken into consideration to ensure appropriate conclusions and extrapolation of findings are made.
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Affiliation(s)
- Charlotte J Green
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Siôn A Parry
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Pippa J Gunn
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Carlo D L Ceresa
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - Fredrik Rosqvist
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
- Department of Public Health and Caring Sciences, Clinical Nutrition and Metabolism, Uppsala University, Uppsala, Sweden
| | - Marie-Eve Piché
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
- Quebec Heart and Lung Institute, Laval University, Quebec, Canada
| | - Leanne Hodson
- University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, Churchill Hospital,Old Road Headington, Oxford OX3 7LE, United Kingdom of Great Britain and Northern Ireland
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Gunn PJ, Green CJ, Pramfalk C, Hodson L. In vitro cellular models of human hepatic fatty acid metabolism: differences between Huh7 and HepG2 cell lines in human and fetal bovine culturing serum. Physiol Rep 2018; 5:5/24/e13532. [PMID: 29263118 PMCID: PMC5742701 DOI: 10.14814/phy2.13532] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 11/02/2017] [Accepted: 11/05/2017] [Indexed: 01/08/2023] Open
Abstract
Human primary hepatocytes are the gold standard for investigating lipid metabolism in nonalcoholic fatty liver disease (NAFLD); however, due to limitations including availability and donor variability, the hepatoma cell lines Huh7 and HepG2 are commonly used. Culturing these cell lines in human serum (HS) has been reported to improve functionality; however, direct comparison of fatty acid (FA) metabolism in response to culturing in HS is lacking. The aim of this study was to compare FA metabolism between HepG2 and Huh7 cells in response to culturing in different sera. Both HepG2 and Huh7 cells were grown in media containing 11 mmol/L glucose and either 2% HS or 10% fetal bovine serum. After 3 days, insulin and insulin-like growth factor-1 signaling were measured. At 7 days, intracellular triacylglycerol (TAG) and media 3-hydroxybutyrate, TAG and apolipoprotein B were measured, as was the FA composition of intracellular TAG and phospholipids. Both cell lines demonstrated higher levels of polyunsaturated fatty acid content, increased insulin sensitivity, higher media TAG levels and increased FA oxidation when cultured in HS Notably, independent of serum type, Huh7 cells had higher intracellular TAG compared to HepG2 cells, which was in part attributable to a higher de novo lipogenesis. Our data demonstrate that intrahepatocellular FA metabolism is different between cell lines and influenced by culturing sera. As a result, when developing a physiologically-relevant model of FA metabolism that could be developed for the study of NAFLD, consideration of both parameters is required.
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Affiliation(s)
- Pippa J Gunn
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford Churchill Hospital, Oxford, United Kingdom
| | - Charlotte J Green
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford Churchill Hospital, Oxford, United Kingdom
| | - Camilla Pramfalk
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford Churchill Hospital, Oxford, United Kingdom .,National Institute for Health Research Oxford Biomedical Research Centre, Oxford University Hospital Trusts, Oxford, United Kingdom
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47
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Pingitore P, Romeo S. The role of PNPLA3 in health and disease. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:900-906. [PMID: 29935383 DOI: 10.1016/j.bbalip.2018.06.018] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 06/12/2018] [Accepted: 06/14/2018] [Indexed: 01/04/2023]
Abstract
The human patatin-like phospholipase domain-containing 3 (PNPLA3) gene encodes for a protein of 481 amino-acids. The variant rs738409 is a cytosine to guanine substitution, encoding for the isoleucine to methionine substitution at position 148 (I148M) of the protein. This variant is strongly associated with the entire spectrum of liver disease. Although this variant is one of the best characterized and deeply studied, the mechanism behind the PNPLA3 and the liver disease is still not well defined. Functionally, it has become clear that the PNPLA3 protein is an enzyme with lipase activity towards triglycerides and retinyl esters, and acyltransferase activity on phospholipids. The aim of this review is to collect the latest data, obtained by in vitro and in vivo experiments, on the functional aspects of the PNPLA3 protein. Defining the precise role of PNPLA3 in the liver lipid metabolism, in order to develop novel therapies for the treatment of liver disease, will be the key of future research.
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Affiliation(s)
- Piero Pingitore
- Department of Molecular and Clinical Medicine, University of Gothenburg, Sweden
| | - Stefano Romeo
- Department of Molecular and Clinical Medicine, University of Gothenburg, Sweden; Cardiology Department, Sahlgrenska University Hospital, Gothenburg, Sweden; Clinical Nutrition Unit, Department of Medical and Surgical Sciences, Magna Graecia University, Catanzaro, Italy.
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48
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Wang X, Wei W, Li NJ, Yuan W, Ding Y, Yang WD, Liu JS, Balamurugan S, Li HY. Heterogeneous expression of human PNPLA3 triggers algal lipid accumulation and lipid droplet enlargement. ALGAL RES 2018. [DOI: 10.1016/j.algal.2018.02.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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49
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Guzman CB, Duvvuru S, Akkari A, Bhatnagar P, Battioui C, Foster W, Zhang XM, Shankar SS, Deeg MA, Chalasani N, Hardy TA, Kazda CM, Pillai SG. Coding variants in PNPLA3 and TM6SF2 are risk factors for hepatic steatosis and elevated serum alanine aminotransferases caused by a glucagon receptor antagonist. Hepatol Commun 2018; 2:561-570. [PMID: 29761171 PMCID: PMC5944587 DOI: 10.1002/hep4.1171] [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: 11/16/2017] [Revised: 02/05/2018] [Accepted: 02/13/2018] [Indexed: 01/04/2023] Open
Abstract
LY2409021 is a glucagon receptor antagonist that was associated with hepatic steatosis and elevated aminotransferases in phase 2 diabetes studies. We investigated the relationship between selected genetic variants and hepatic steatosis and elevated alanine aminotransferases (ALTs) associated with LY2409021. Patients participated in a 6‐week placebo‐controlled trial (I1R‐MC‐GLDI [GLDI], n = 246) and a 52‐week placebo‐ and active comparator‐controlled trial (I1R‐MC‐GLDJ [GLDJ], n = 158). GLDJ had endpoints at 6 months, including measures of hepatic fat fraction (HFF) by magnetic resonance imaging. The five genes tested were patatin‐like phospholipase domain containing 3 (PNPLA3) (rs738409 and rs738491), transmembrane 6 superfamily member 2 (TM6SF2) (rs58542926), peroxisome proliferative activated receptor gamma coactivator 1 alpha (PPARGC1A) (rs4361373, rs3774921, rs2970849), adenylate cyclase 3 (ADCY3) (rs713586), and insulin‐like growth factor 1 (IGF‐1) (rs1520220). In GLDI, PNPLA3 I148M (P = 0.001) and TM6SF2 E167K (P = 0.001) were significantly associated with an increase in ALT at 6 weeks for LY2409021 but not for placebo. In GLDJ, PNPLA3 I148M showed the same effect (P = 0.007) on ALT at 6 months but the placebo or sitagliptin did not. In GLDJ, both PNPLA3 and TM6SF2 risk‐allele carriers showed increases in HFF that were numerically greater but not statistically significant. The carriers of PNPLA3 and/or TM6SF2 risk alleles showed significantly increased ALT (GLDI, +13.28 U/L in carriers versus +4.84 U/L in noncarriers, P = 4 × 10–5; GLDJ, +14.6 U/L in carriers versus +1.7 in noncarriers, P = 0.0018) and HFF (GLDJ, +5.35% in carriers versus 2.38% in noncarriers, P = 0.048). Elevation of transaminase and HFF were also noted in the noncarriers but at a significantly lower degree. Conclusion: The carriers of PNPLA3 and/or TM6SF2 variant alleles are at risk for hepatic steatosis and elevated ALT levels caused by LY2409021, a glucagon receptor antagonist. More studies are needed to investigate if our observations are generalizable to hepatic steatosis caused by other medications. (Hepatology Communications 2018;2:561‐570)
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Affiliation(s)
- Cristina B Guzman
- Eli Lilly and Company Indianapolis IN.,Present address: Enanta Pharmaceuticals Inc Watertown MA
| | - Suman Duvvuru
- Eli Lilly and Company Indianapolis IN.,Present address: Amazon Seattle WA
| | | | | | | | | | | | - Sudha S Shankar
- Eli Lilly and Company Indianapolis IN.,Present address: NGM Biopharmaceuticals San Francisco CA
| | - Mark A Deeg
- Eli Lilly and Company Indianapolis IN.,Present address: Regulus Pharmaceuticals San Diego CA
| | - Naga Chalasani
- Indiana University Department of Medicine Indianapolis IN
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50
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Mitsche MA, Hobbs HH, Cohen JC. Patatin-like phospholipase domain–containing protein 3 promotes transfer of essential fatty acids from triglycerides to phospholipids in hepatic lipid droplets. J Biol Chem 2018; 293:6958-6968. [PMID: 29555681 PMCID: PMC5936833 DOI: 10.1074/jbc.ra118.002333] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 03/14/2018] [Indexed: 12/30/2022] Open
Abstract
Fatty liver disease (FLD) is a burgeoning health problem. A missense variant (I148M) in patatin-like phospholipase domain-containing protein 3 (PNPLA3) confers susceptibility to FLD, although the mechanism is not known. To glean first insights into the physiological function of PNPLA3, we performed detailed lipidomic profiling of liver lysates and lipid droplets (LDs) from WT and Pnpla3-/- (KO) mice and from knock-in (ki) mice expressing either the 148M variant (IM-ki mice) or a variant (S47A) that renders the protein catalytically inactive (SA-ki mice). The four strains differed in composition of very-long-chain polyunsaturated fatty acids (vLCPUFA) in hepatic LDs. In the LDs of IM-ki mice, vLCPUFAs were depleted from triglycerides and enriched in phospholipids. Conversely, vLCPUFAs were enriched in triglycerides and depleted from phospholipids in SA-ki and Pnpla3-/- mice. Release of vLCPUFAs from hepatic LDs incubated ex vivo was increased in droplets from IM-ki mice and decreased from droplets isolated from Pnpla3-/- and SA-ki mice relative to those of WT mice. Thus, the physiological role of PNPLA3 appears to be to remodel triglycerides and phospholipids in LDs, perhaps to accommodate changes in LD size in response to feeding. Because SA-ki and IM-ki both cause FLD and yet have opposite effects on the lipidomic profile of LDs, we conclude that the FLD associated with genetic variation in PNPLA3 is not related to the enzyme's role in remodeling LD lipids.
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Affiliation(s)
- Matthew A Mitsche
- From the Departments of Molecular Genetics and Internal Medicine.,Center of Human Nutrition, and
| | - Helen H Hobbs
- From the Departments of Molecular Genetics and Internal Medicine, .,Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Jonathan C Cohen
- From the Departments of Molecular Genetics and Internal Medicine, .,Center of Human Nutrition, and
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