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PPAR agonists for the treatment of primary biliary cholangitis: Old and new tales. J Transl Autoimmun 2023; 6:100188. [PMID: 36684809 PMCID: PMC9850184 DOI: 10.1016/j.jtauto.2023.100188] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 12/30/2022] [Accepted: 01/02/2023] [Indexed: 01/06/2023] Open
Abstract
Introduction Primary biliary cholangitis (PBC) is an autoimmune liver disease involving the small intrahepatic bile ducts; when untreated or undertreated, it may evolve to liver fibrosis and cirrhosis. Ursodeoxycholic Acid (UDCA) is the standard of care treatment, Obeticholic Acid (OCA) has been approved as second-line therapy for those non responder or intolerant to UDCA. However, due to moderate rate of UDCA-non responders and to warnings recently issued against OCA use in patients with cirrhosis, further therapies are needed.Areas covered. Deep investigations into the pathogenesis of PBC is leading to proposal of new therapeutic agents, among which peroxisome proliferator-activated receptor (PPAR) ligands seem to be highly promising given the preliminary, positive results in Phase 2 and 3 trials. Bezafibrate, the most evaluated, is currently used in clinical practice in combination with UDCA in referral centers. We herein describe completed and ongoing trials involving PPAR agonists use in PBC, analyzing pits and falls. Expert opinion Testing new therapeutic opportunities in PBC is challenging due to its low prevalence and slow progression. However, new drugs including PPAR agonists, are currently under investigation and should be considered for at-risk PBC patients.
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Key Words
- AEs, adverse events
- AIH, Autoimmune Hepatitis
- ALP, Alkaline Phosphatase
- AMA, Antimitochondrial antibodies
- BZF, Bezafibrate
- CKD, chronic kidney disease
- Elafibranor
- FDA, Food and Drug
- FF, Fenofibrate
- FXR, Farnesoid X Receptor
- Fibrates
- GGT, γ-glutamil transferase
- HCC, Hepatocellular Carcinoma
- HDL, high-density lipoprotein
- HR, Hazard Ratio
- HSC, Hepatic Stellate Cells
- IL-1β, Interleukin-1
- IgM, Immunoglobulin M
- LDL, low-density- lipoprotein
- LT, Liver Transplant
- MDR3, multidrug resistance protein 3
- NASH, Non Alcoholic Steato-Hepatits
- NRS, Numerical Raing Scale
- OCA, Obeticholic Acid
- OR, Odds Ratio
- PAR, protease-activated receptors
- PBC, Primary Biliary Cholangitis
- PC, phosphatidylcholine
- PH, Portal Hypertension
- PPAR agonists
- PPAR, peroxisome proliferator-activated receptor
- Primary biliary cholangitis
- QoL, Quality of Life
- RCT, randomized controlled trial
- SAE, Severe Adverse Event
- Saroglitazar
- Seladelpar
- TGR, transmembrane G protein-coupled receptor
- TLR, Toll Like Receptor
- TNF-α, Tumor Necrosis Factor- α
- UDCA
- UDCA, ursodeoxycholic acid
- UK, United Kingdom
- ULN, upper limit of normal
- VAS, Visual Analogue Scale
- VRS, Verbal Rating Scale
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Dietary polyphenols and their relationship to the modulation of non-communicable chronic diseases and epigenetic mechanisms: A mini-review. FOOD CHEMISTRY. MOLECULAR SCIENCES 2022; 6:100155. [PMID: 36582744 PMCID: PMC9793217 DOI: 10.1016/j.fochms.2022.100155] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 10/18/2022] [Accepted: 12/11/2022] [Indexed: 12/14/2022]
Abstract
Chronic Non-Communicable Diseases (NCDs) have been considered a global health problem, characterized as diseases of multiple factors, which are developed throughout life, and regardless of genetics as a risk factor of important relevance, the increase in mortality attributed to the disease to environmental factors and the lifestyle one leads. Although the reactive species (ROS/RNS) are necessary for several physiological processes, their overproduction is directly related to the pathogenesis and aggravation of NCDs. In contrast, dietary polyphenols have been widely associated with minimizing oxidative stress and inflammation. In addition to their antioxidant power, polyphenols have also drawn attention for being able to modulate both gene expression and modify epigenetic alterations, suggesting an essential involvement in the prevention and/or development of some pathologies. Therefore, this review briefly explained the mechanisms in the development of some NCDs, followed by a summary of some evidence related to the interaction of polyphenols in oxidative stress, as well as the modulation of epigenetic mechanisms involved in the management of NCDs.
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Key Words
- 8-oxodG, 8-oxo-2́deosyguanosine
- ABCG, ATP Binding Cassette Subfamily G Member
- ADAM10, α-secretase
- ADRB3, adrenoceptor Beta 3
- APP, amyloid-β precursor protein
- ARF, auxin response factor
- ARH-I, aplysia ras homology member I
- ARHGAP24, Rho GTPase Activating Protein 24
- ATF6, activating transcription factor 6
- ATP2A3, ATPase Sarcoplasmic/Endoplasmic Reticulum Ca2+ Transporting 3
- BCL2L14, apoptosis facilitator Bcl-2-like protein 14
- Bioactive compounds
- CDH1, cadherin-1
- CDKN, cyclin dependent kinase inhibitor
- CPT, carnitine palmitoyltransferase
- CREBH, cyclic AMP-responsive element-binding protein H
- DANT2, DXZ4 associated non-noding transcript 2, distal
- DAPK1, death-associated protein kinase 1
- DNA methylation
- DNMT, DNA methyltransferase
- DOT1L, disruptor of telomeric silencing 1-like
- EWASs, epigenome-wide association studies
- EZH2, Enhancer of zeste homolog 2
- FAS, Fas cell Surface Death Receptor
- GDNF, glial cell line-derived neurotrophic factor
- GFAP, glial fibrillary acid protein
- GSTP1, Glutathione S-transferases P1
- Gut microbiota modulation
- HAT, histone acetylases
- HDAC, histone deacetylases
- HSD11B2, 11 beta-hydroxysteroid dehydrogenase type 2
- Histone modifications
- IGFBP3, insulin-like growth factor-binding protein 3
- IGT, impaired glucose tolerance
- KCNK3, potassium two pore domain channel subfamily K Member 3
- MBD4, methyl-CpG binding domain 4
- MGMT, O-6-methylguanine-DNA methyltransferase
- NAFLD, Non-alcoholic fatty liver disease
- OCT1, Organic cation transporter 1
- OGG1, 8-Oxoguanine DNA Glycosylase
- Oxidative stress
- PAI-1, plasminogen activator inhibitor 1
- PHOSPHO1, Phosphoethanolamine/Phosphocholine Phosphatase 1
- PLIN1, perilipin 1
- POE3A, RNA polymerase III
- PPAR, peroxisome proliferator-activated receptor
- PPARGC1A, PPARG coactivator 1 alpha
- PRKCA, Protein kinase C alpha
- PTEN, phosphatase and tensin homologue
- Personalized nutrition
- RASSF1A, Ras association domain family member 1
- SAH, S -adenosyl-l-homocysteine
- SAM, S-adenosyl-methionine
- SD, sleep deprivation
- SOCS3, suppressor of cytokine signaling 3
- SREBP-1C, sterol-regulatory element binding protein-1C
- TBX2, t-box transcription factor 2
- TCF7L2, transcription factor 7 like 2
- TET, ten-eleven translocation proteins
- TNNT2, cardiac muscle troponin T
- TPA, 12-O-tetradecanoylphorbol-13-acetate
- lncRNA, long non-coding RNA
- ncRNA, non-coding RNA
- oAβ-induced-LTP, oligomeric amyloid-beta induced long term potentiation
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Saroglitazar for Nonalcoholic Fatty Liver Disease: A Single Centre Experience in 91 Patients. J Clin Exp Hepatol 2022; 12:435-439. [PMID: 35535066 PMCID: PMC9077151 DOI: 10.1016/j.jceh.2021.06.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 06/12/2021] [Indexed: 12/12/2022] Open
Abstract
Background Saroglitazar is a novel, dual peroxisome proliferator-activated receptors-α/γ agonist and is being investigated for the treatment of nonalcoholic fatty liver disease (NAFLD). Patients and methods Consecutive overweight (body mass index [BMI] >23 kg/m2) patients of NAFLD, diagnosed based on controlled attenuation parameter (CAP) >248 dB/m, and attending the outpatient department of a tertiary care centre in New Delhi, were enrolled. Patients with cirrhosis (liver stiffness measurement [LSM] >13.5 kPa) and those with concomitant liver disease due to other aetiologies (alcohol, viral, etc.) were excluded. All patients received saroglitazar 4 mg/day; in addition, they were advised to reduce weight and were counselled regarding diet and exercise. At 3-month follow-up, patients were categorized into those who were able to reduce ≥5% body weight and those who could n'ot, and both these groups were compared. Results A total of 91 patients (median age 45 years [range 18-66 years]; 81% men) were included in the study. The median BMI was 29.3 kg/m2 (range 23.6-42.2 kg/m2). The baseline median (range) aspartate transaminase, alanine transaminase, gamma glutamyl transferase, LSM and CAP values were 40 IU/dL (range 22-144 IU/dL), 48 IU/dL (range 13-164 IU/dL), 42 IU/dL (range 4-171 IU/dL), 6.7 kPa (range 3.6-13.1 kPa), and 308 dB/m (range 249-400 dB/m). All patients tolerated saroglitazar well. At 3-month, 57 patients (63%) were able to reduce ≥5% weight, whereas in the remaining 34 patients (37%), the weight reduction was <5% from baseline. Transaminases values improved in both the groups; however, LSM and CAP values improved only in patients who reduced weight. Conclusion In overweight patients with NAFLD, a 3-month therapy with saroglitazar is able to improve transaminases but not LSM and CAP values unless accompanied by weight reduction of at least 5%. Larger randomized controlled trials are needed to document the independent effect of saroglitazar in these patients.
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Key Words
- ALP, alkaline phosphatase
- ALT, alanine transaminase
- AST, aspartate transaminase
- BMI, body mass index
- CAP, controlled attenuation parameter
- DCGI, Drug Controller General of India
- FDA, Food and Drug Administration
- GGT, gamma glutamyl transferase
- HCV, hepatitis C virus
- IQR, interquartile range
- IU, international units
- LSM, liver stiffness measurement
- MAFLD, metabolic (dysfunction) associated fatty liver disease
- NAFLD
- NAFLD, nonalcoholic fatty liver disease
- NASH, nonalcoholic steatohepatitis
- PPAR, peroxisome proliferator-activated receptor
- controlled attenuation parameter
- dB, decibels
- kPa, kilopascal
- obesity
- pPAR agonist
- saroglitazar
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The clinical translation of eicosanoids and other oxylipins, although challenging, should be actively pursued. J Mass Spectrom Adv Clin Lab 2021; 21:27-30. [PMID: 34820674 PMCID: PMC8600996 DOI: 10.1016/j.jmsacl.2021.08.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 08/19/2021] [Accepted: 08/19/2021] [Indexed: 01/02/2023] Open
Key Words
- CE, cholesteryl ester
- CVD, cardiovascular disease
- LDL, low density lipoprotein
- NFκB, nuclear factor kappa B
- PC, phosphatidylcholine
- PL, phospholipid
- PPAR, peroxisome proliferator-activated receptor
- PUFA, polyunsaturated fatty acid
- TG, triglyceride
- oxCE, oxidized CE
- oxLDL, oxidized LDL
- oxTG, oxidized TG
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Deficiency of peroxisome proliferator-activated receptor α attenuates apoptosis and promotes migration of vascular smooth muscle cells. Biochem Biophys Rep 2021; 27:101091. [PMID: 34381883 PMCID: PMC8339143 DOI: 10.1016/j.bbrep.2021.101091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 07/23/2021] [Accepted: 07/26/2021] [Indexed: 11/29/2022] Open
Abstract
Peroxisome proliferator-activated receptor (PPAR) α is widely expressed in the vasculature and has pleiotropic and lipid-lowering independent effects, but its role in the growth and function of vascular smooth muscle cells (VSMCs) during vascular pathophysiology is still unclear. Herein, VSMC-specific PPARα-deficient mice (Ppara ΔSMC) were generated by Cre-LoxP site-specific recombinase technology and VSMCs were isolated from mice aorta. PPARα deficiency attenuated VSMC apoptosis induced by angiotensin (Ang) II and hydrogen peroxide, and increased the migration of Ang II-challenged cells.
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Key Words
- Ang II, angiotensin II
- Angiotensin II
- EC, endothelial cell
- ECM, extracellular matrix
- ERK, extracellular signal-regulated kinase
- MAPK, mitogen-activated protein kinase
- MCP-1, monocyte chemoattractant protein-1
- PCR, polymerase chain reaction
- PPAR, peroxisome proliferator-activated receptor
- PPARα
- SM22α, smooth muscle 22α
- TGF, tumor growth factor
- TUNEL, terminal deoxynucleotidyl transferase dUTP nick end labeling
- VSMC, vascular smooth muscle cell
- Vascular remodeling
- Vascular smooth muscle cell
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High-Fat Diet Enhances Neutrophil Adhesion in LDLR-Null Mice Via Hypercitrullination of Histone H3. ACTA ACUST UNITED AC 2021; 6:507-523. [PMID: 34222722 PMCID: PMC8246031 DOI: 10.1016/j.jacbts.2021.04.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 04/06/2021] [Accepted: 04/07/2021] [Indexed: 12/21/2022]
Abstract
Neutrophil adhesion on the atheroprone femoral artery of high-fat diet-fed low-density lipoprotein receptor-null mice was enhanced more than in wild-type mice. The inhibition of histone H3 citrullination of neutrophils reversed the enhancement of neutrophil adhesion, suggesting that hypercitrullination contributes to enhanced neutrophil adhesion. Furthermore, pemafibrate reduced the citrullination of histone H3 in these mice. Therefore, the hypercitrullination of histone H3 in neutrophils contributes to atherosclerotic vascular inflammation.
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Key Words
- BM, bone marrow
- BW, body weight
- DNaseI, deoxyribonuclease I
- GM-CSF, granulocyte-macrophage colony-stimulating factor
- HFD, high-fat diet
- HUVECs, human umbilical vein endothelial cells
- IVM, intravital microscopy
- LDLR, low-density lipoprotein receptor
- LysM, lysosome M
- MPO, myeloperoxidase
- NC, normal chow
- NE, neutrophil elastase
- NET, neutrophil extracellular trap
- PAD4, peptidylarginine deiminase 4
- PPAR, peroxisome proliferator-activated receptor
- TC, total cholesterol
- TDFA, N-acetyl-l-threonyl-l-α-aspartyl-N5-(2-fluoro-1-iminoethyl)-l-ornithinamide trifluoroacetate salt
- TG, triglyceride
- citrullination
- cxcl1
- eGFP, enhanced green fluorescent protein
- in vivo imaging
- neutrophil
- vascular inflammation
- wt, wild type
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Multiblock metabolomics: An approach to elucidate whole-body metabolism with multiblock principal component analysis. Comput Struct Biotechnol J 2021; 19:1956-1965. [PMID: 33995897 PMCID: PMC8086023 DOI: 10.1016/j.csbj.2021.04.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 03/20/2021] [Accepted: 04/04/2021] [Indexed: 12/16/2022] Open
Abstract
“Multiblock metabolomics” elucidates the global metabolic network in a whole body. “Multiblock metabolomics” combines LC/MS-based metabolomics with multiblock PCA. “Multiblock metabolomics” highlights and elicits organ-specific metabolism. TGs with less unsaturated fatty acids were highly accumulated in the diabetic liver.
Principal component analysis (PCA) is a useful tool for omics analysis to identify underlying factors and visualize relationships between biomarkers. However, this approach is limited in addressing life complexity and further improvement is required. This study aimed to develop a new approach that combines mass spectrometry-based metabolomics with multiblock PCA to elucidate the whole-body global metabolic network, thereby generating comparable metabolite maps to clarify the metabolic relationships among several organs. To evaluate the newly developed method, Zucker diabetic fatty (ZDF) rats (n = 6) were used as type 2 diabetic models and Sprague Dawley (SD) rats (n = 6) as controls. Metabolites in the heart, kidney, and liver were analyzed by capillary electrophoresis and liquid chromatography mass spectrometry, respectively, and the detected metabolites were analyzed by multiblock PCA. More than 300 metabolites were detected in the heart, kidney, and liver. When the metabolites obtained from the three organs were analyzed with multiblock PCA, the score and loading maps obtained were highly synchronized and their metabolism patterns were visually comparable. A significant finding in this study was the different expression patterns in lipid metabolism among the three organs; notably triacylglycerols with polyunsaturated fatty acids or less unsaturated fatty acids showed specific accumulation patterns depending on the organs.
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Key Words
- AMP, adenosine monophosphate
- Biomarkers
- CE/MS, capillary electrophoresis mass spectrometry
- CV, coefficient of variation
- ESI, electrospray ionization
- FABP, fatty acid-binding protein
- GC/MS, gas chromatography mass spectrometry
- LC/MS, liquid chromatography mass spectrometry
- Mass spectrometry
- Metabolomics
- Multiblock PCA
- PCA, principal component analysis
- PPAR, peroxisome proliferator-activated receptor
- QC, quality control
- SD, Sprague Dawley
- TCA, tricarboxylic acid. CoA, coenzyme A
- TG, triacylglycerol
- Type 2 Diabetes
- UPLC, ultra-performance liquid chromatography
- ZDF, Zucker diabetic fatty
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Genetic predisposition similarities between NASH and ASH: Identification of new therapeutic targets. JHEP Rep 2021; 3:100284. [PMID: 34027340 PMCID: PMC8122117 DOI: 10.1016/j.jhepr.2021.100284] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 03/09/2021] [Accepted: 03/15/2021] [Indexed: 12/12/2022] Open
Abstract
Fatty liver disease can be triggered by a combination of excess alcohol, dysmetabolism and other environmental cues, which can lead to steatohepatitis and can evolve to acute/chronic liver failure and hepatocellular carcinoma, especially in the presence of shared inherited determinants. The recent identification of the genetic causes of steatohepatitis is revealing new avenues for more effective risk stratification. Discovery of the mechanisms underpinning the detrimental effect of causal mutations has led to some breakthroughs in the comprehension of the pathophysiology of steatohepatitis. Thanks to this approach, hepatocellular fat accumulation, altered lipid droplet remodelling and lipotoxicity have now taken centre stage, while the role of adiposity and gut-liver axis alterations have been independently validated. This process could ignite a virtuous research cycle that, starting from human genomics, through omics approaches, molecular genetics and disease models, may lead to the development of new therapeutics targeted to patients at higher risk. Herein, we also review how this knowledge has been applied to: a) the study of the main PNPLA3 I148M risk variant, up to the stage of the first in-human therapeutic trials; b) highlight a role of MBOAT7 downregulation and lysophosphatidyl-inositol in steatohepatitis; c) identify IL-32 as a candidate mediator linking lipotoxicity to inflammation and liver disease. Although this precision medicine drug discovery pipeline is mainly being applied to non-alcoholic steatohepatitis, there is hope that successful products could be repurposed to treat alcohol-related liver disease as well.
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Key Words
- AA, arachidonic acid
- ASH, alcoholic steatohepatitis
- DAG, diacylglycerol
- DNL, de novo lipogenesis
- ER, endoplasmic reticulum
- FFAs, free fatty acids
- FGF19, fibroblast growth factor 19
- FLD, fatty liver disease
- FXR, farnesoid X receptor
- GCKR, glucokinase regulator
- GPR55, G protein-coupled receptor 55
- HCC, hepatocellular carcinoma
- HFE, homeostatic iron regulator
- HSC, hepatic stellate cells
- HSD17B13, hydroxysteroid 17-beta dehydrogenase 13
- IL-, interleukin-
- IL32
- LDs, lipid droplets
- LPI, lysophosphatidyl-inositol
- MARC1, mitochondrial amidoxime reducing component 1
- MBOAT7
- MBOAT7, membrane bound O-acyltransferase domain-containing 7
- NASH, non-alcoholic steatohepatitis
- PNPLA3
- PNPLA3, patatin like phospholipase domain containing 3
- PPAR, peroxisome proliferator-activated receptor
- PRS, polygenic risk score
- PUFAs, polyunsaturated fatty acids
- SREBP, sterol response element binding protein
- TAG, triacylglycerol
- TNF-α, tumour necrosis factor-α
- alcoholic liver disease
- cirrhosis
- fatty liver disease
- genetics
- interleukin-32
- non-alcoholic fatty liver disease
- precision medicine
- steatohepatitis
- therapy
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Defatting strategies in the current era of liver steatosis. JHEP Rep 2021; 3:100265. [PMID: 34027337 PMCID: PMC8121960 DOI: 10.1016/j.jhepr.2021.100265] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Revised: 02/14/2021] [Accepted: 02/19/2021] [Indexed: 12/25/2022] Open
Abstract
Liver steatosis is emerging as a major cause of chronic liver disease worldwide, mainly due to the increasing rate of obesity, type 2 diabetes, and metabolic syndrome. Because of the increased incidence of liver steatosis, many organs are currently declined for transplantation despite high demand and waiting list mortality. Defatting strategies have recently emerged as a means of rapidly reducing liver steatosis to expand the pool of available organs. This review summarises advances in defatting strategies in experimental and human models of liver steatosis over the last 20 years.
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Key Words
- GDNF, glial cell-line derived neurotrophic factor
- HFD, high-fat diet
- HIEC, hepatic endothelial cells
- HOPE, hypothermic machine perfusion
- LDs, lipid droplets
- Macrosteatosis
- NAFL, non-alcoholic fatty liver
- NAFLD, non-alcoholic fatty liver disease
- NASH, non-alcoholic steatohepatitis
- NEsLP, normothermic ex situ machine perfusion
- PHHs, primary human hepatocytes
- PPAR, peroxisome proliferator-activated receptor
- PXR, pregnane X receptor
- SCS, static cold storage
- SRS, steatosis reduction supplements
- TG, triglyceride
- ischemia-reperfusion injury
- liver transplantation
- machine perfusion
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Aramchol downregulates stearoyl CoA-desaturase 1 in hepatic stellate cells to attenuate cellular fibrogenesis. JHEP Rep 2021; 3:100237. [PMID: 34151243 PMCID: PMC8189934 DOI: 10.1016/j.jhepr.2021.100237] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 01/13/2021] [Accepted: 01/17/2021] [Indexed: 02/07/2023] Open
Abstract
Background & Aims Aramchol is a fatty acid-bile acid conjugate that reduces liver fat content and is being evaluated in a phase III clinical trial for non-alcoholic steatohepatitis (NASH). Aramchol attenuates NASH in mouse models and decreases steatosis by downregulating the fatty acid synthetic enzyme stearoyl CoA desaturase 1 (SCD1) in hepatocytes. Although hepatic stellate cells (HSCs) also store lipids as retinyl esters, the impact of Aramchol in this cell type is unknown. Methods We investigated the effects of Aramchol on a human HSC line (LX-2), primary human HSCs (phHSCs), and primary human hepatocytes (phHeps). Results In LX-2 and phHSCs, 10 μM Aramchol significantly reduced SCD1 mRNA while inducing PPARG (PPARγ) mRNA, with parallel changes in the 2 proteins; ACTA2, COL1A1, β-PDGFR (bPDGFR) mRNAs were also significantly reduced in LX-2. Secretion of collagen 1 (Col1α1) was inhibited by 10 μM Aramchol. SCD1 knockdown in LX-2 cells phenocopied the effect of Aramchol by reducing fibrogenesis, and addition of Aramchol to these cells did not rescue fibrogenic gene expression. Conversely, in LX-2 overexpressing SCD1, Aramchol no longer suppressed fibrogenic gene expression. The drug also induced genes in LX-2 that promote cholesterol efflux and inhibited ACAT2, which catalyses cholesterol synthesis. In phHeps, Aramchol also reduced SCD1 and increased PPARG mRNA expression. Conclusions Aramchol downregulates SCD1 and elevates PPARG in HSCs, reducing COL1A1 and ACTA2 mRNAs and COL1A1 secretion. These data suggest a direct inhibitory effect of Aramchol in HSCs through SCD1 inhibition, as part of a broader impact on both fibrogenic genes as well as mediators of cholesterol homeostasis. These findings illustrate novel mechanisms of Aramchol activity, including potential antifibrotic activity in patients with NASH and fibrosis. Lay summary In this study, we have explored the potential activity of Aramchol, a drug currently in clinical trials for fatty liver disease, in blocking fibrosis, or scarring, by hepatic stellate cells, the principal collagen-producing (i.e. fibrogenic) cell type in liver injury. In both isolated human hepatic stellate cells and in a human hepatic stellate cell line, the drug suppresses the key fat-producing enzyme, stearoyl CoA desaturase 1 (SCD1), which leads to reduced expression of genes and proteins associated with hepatic fibrosis, while inducing the protective gene, PPARγ. The drug loses activity when SCD1 is already reduced by gene knockdown, reinforcing the idea that inhibition of SCD1 is a main mode of activity for Aramchol. These findings strengthen the rationale for testing Aramchol in patients with NASH. The antifibrotic activity of Aramchol was assessed in human hepatic stellate cells (HSCs). Aramchol reduces fibrogenic gene expression by inhibiting SCD1 and inducing PPARγ. Aramchol inhibits pathways that increase HSC cholesterol content. The antifibrotic activity of Aramchol reinforces its potential efficacy in human NASH.
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Key Words
- ABCA1, ATP-binding cassette transporter 1
- EMT, epithelial-mesenchymal-transition
- Fatty liver disease
- Fibrosis
- GSEA, gene set enrichment analysis
- GSH, glutathione
- GSSG, glutathione disulfide
- HRP, horse radish peroxidase
- HSC, hepatic stellate cell
- Hepatic fibrosis
- Hh, Hedgehog
- MCD, methionine-choline depleted diet
- MMP-2, matrix metalloproteinase 2
- MUFAs, monounsaturated fatty acids
- NAFLD, non-alcoholic fatty liver disease
- NASH, non-alcoholic steatohepatitis
- Non-alcoholic steatohepatitis
- PDMS, polydimethylsiloxane
- PPAR, peroxisome proliferator-activated receptor
- SCD1, stearoyl CoA-desaturase 1
- SMA, smooth muscle actin
- TAA, thioacetamide
- phHSCs, primary human hepatic stellate cells
- phHeps, primary human hepatocytes
- siRNA, small inhibitory RNA
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Osteoblastic differentiation improved by bezafibrate-induced mitochondrial biogenesis in deciduous tooth-derived pulp stem cells from a child with Leigh syndrome. Biochem Biophys Rep 2018; 17:32-37. [PMID: 30533535 PMCID: PMC6262801 DOI: 10.1016/j.bbrep.2018.11.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 10/09/2018] [Accepted: 11/12/2018] [Indexed: 01/07/2023] Open
Abstract
Leigh syndrome is a highly heterogeneous condition caused by pathological mutations in either nuclear or mitochondrial DNA regions encoding molecules involved in mitochondrial oxidative phosphorylation, in which many organs including the brain can be affected. Among these organs, a high incidence of poor bone health has been recognized in primary mitochondrial diseases including Leigh syndrome. However, the direct association between mitochondrial dysfunction and poor bone health has not been fully elucidated. Mitochondrial biosynthesis is a potential therapeutic target for this syndrome, as it can ameliorate the impairment of oxidative phosphorylation without altering these gene mutations. A recent study has shown the impaired osteogenesis in the dental pulp stem cells derived from the deciduous teeth of a child with Leigh syndrome, harboring the heteroplasmic mutation G13513A in the mitochondrial DNA region encoding the ND5 subunit of the respiratory chain complex I. The present study aimed to investigate whether mitochondrial biogenesis could be a therapeutic target for improving osteogenesis, using the same stem cells in a patient-specific cellular model. For this purpose, bezafibrate was used because it has been reported to induce mitochondrial biogenesis as well as to improve bone metabolism and osteoporosis. Bezafibrate clearly improved the differentiation of patient-derived stem cells into osteoblasts and the mineralization of differentiated osteoblasts. The mRNA expression of peroxisome proliferator-activated receptor-gamma coactivator-1α, ATP production, and mitochondrial Ca2+ levels were all significantly increased by bezafibrate in the patient-derived cells. In addition, the increased amount and morphological shift from the fragmentary to network shape associated with DRP1 downregulation were also observed in the bezafibrate-treated patient-derived cells. These results suggest that mitochondrial biogenesis may be a potential therapeutic target for improving osteogenesis in patients with Leigh syndrome, and bezafibrate may be one of the candidate treatment agents. Dental pulp stem cells from a child with Leigh syndrome have impaired osteogenesis. Bezafibrate-PGC-1α pathway improves osteogenesis via mitochondrial biogenesis. Bezafibrate also induces DRP1 downregulation and mitochondrial network formation. Dental pulp stem cells may help to establish treatment strategies for Leigh syndrome.
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Key Words
- BZF, bezafibrate
- Bezafibrate
- DRP1, dynamin-related protein 1
- Dental pulp stem cell
- LS, Leigh syndrome
- Leigh syndrome
- MMP, Mitochondrial membrane potential
- Mitochondrial biogenesis
- OXPHOS, oxidative phosphorylation
- Osteogenesis
- PGC-1α, peroxisome proliferator-activated receptor-gamma coactivator-1α
- PPAR, peroxisome proliferator-activated receptor
- RC complex I, respiratory chain complex I
- SHED, Stem cells from human exfoliated deciduous teeth
- mtDNA, mitochondrial DNA
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Apolipoprotein A-I Reduces In-Stent Restenosis and Platelet Activation and Alters Neointimal Cellular Phenotype. JACC Basic Transl Sci 2018; 3:200-209. [PMID: 30062205 PMCID: PMC6060078 DOI: 10.1016/j.jacbts.2017.11.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 10/20/2017] [Accepted: 11/13/2017] [Indexed: 11/04/2022]
Abstract
Even the most advanced drug-eluting stents evoke unresolved issues, including chronic inflammation, late thrombosis, and neoatherosclerosis. This highlights the need for novel strategies that improve stent biocompatibility. Our studies show that apolipoprotein A-I (apoA-I) reduces in-stent restenosis and platelet activation, and enhances endothelialization. These findings have therapeutic implications for improving stent biocompatibility.
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Key Words
- ABCA1, ATP-binding cassette transporter A1
- CAD, coronary artery disease
- DES, drug-eluting stent(s)
- HDL, high-density lipoprotein
- PBS, phosphate-buffered saline
- PCI, percutaneous coronary intervention
- PPAR, peroxisome proliferator-activated receptor
- SMC, smooth muscle cell
- apoA-I, apolipoprotein A-I
- apoE−/−, apolipoprotein E deficient
- apolipoprotein A-I
- endothelialization
- neointimal hyperplasia
- platelet activation
- rHDL, reconstituted high- density lipoprotein
- stent biocompatibility
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Nod-Like Receptor Pyrin-Containing Protein 6 (NLRP6) Is Up-regulated in Ileal Crohn's Disease and Differentially Expressed in Goblet Cells. Cell Mol Gastroenterol Hepatol 2018; 6:110-112.e8. [PMID: 29928676 PMCID: PMC6007817 DOI: 10.1016/j.jcmgh.2018.03.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 03/05/2018] [Indexed: 12/13/2022]
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Protocols and pitfalls in obtaining fatty acid-binding proteins for biophysical studies of ligand-protein and protein-protein interactions. Biochem Biophys Rep 2017; 10:318-324. [PMID: 28955759 PMCID: PMC5614677 DOI: 10.1016/j.bbrep.2017.05.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 04/26/2017] [Accepted: 05/03/2017] [Indexed: 01/22/2023] Open
Abstract
Adipocyte fatty acid-binding protein (AFABP: FABP4) is a member of the intracellular lipid-binding protein family that is thought to target long-chain fatty acids to nuclear receptors such as peroxisome proliferator-activated receptor gamma (PPARγ), which in turn plays roles in insulin resistance and obesity. A molecular understanding of AFABP function requires robust isolation of the protein in liganded and free forms as well as characterization of its oligomerization state(s) under physiological conditions. We report development of a protocol to optimize the production of members of this protein family in pure form, including removal of their bound lipids by mixing with hydrophobically functionalized hydroxypropyl dextran beads and validation by two-dimensional NMR spectroscopy. The formation of self-associated or covalently bonded protein dimers was evaluated critically using gel filtration chromatography, revealing conditions that promote or prevent formation of disulfide-linked homodimers. The resulting scheme provides a solid foundation for future investigations of AFABP interactions with key ligand and protein partners involved in lipid metabolism.
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Key Words
- AFABP, adipose fatty acid-binding protein
- Delipidation
- Disulfide bond
- ESI-MS, Electrospray Ionization Mass Spectrometry
- FABP, fatty acid-binding protein
- Fatty acid-binding protein
- GF, Gel filtration chromatography
- HSQC, [1H–15N] heteronuclear single quantum correlation spectroscopy
- Homodimer
- LCFA, Long-chain fatty acid
- Ligand
- MALDI-TOF, Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry
- NMR, Nuclear Magnetic Resonance
- NOESY, 2D nuclear Overhauser spectroscopy
- PPAR, peroxisome proliferator-activated receptor
- Protein
- TCEP, tris(2-carboxyethyl)phosphine
- TEV, Tobacco Etch Virus
- TOCSY, 2D Total correlation spectroscopy
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Bezafibrate ameliorates diabetes via reduced steatosis and improved hepatic insulin sensitivity in diabetic TallyHo mice. Mol Metab 2017; 6:256-266. [PMID: 28271032 PMCID: PMC5323884 DOI: 10.1016/j.molmet.2016.12.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 12/08/2016] [Accepted: 12/15/2016] [Indexed: 12/31/2022] Open
Abstract
OBJECTIVE Recently, we have shown that Bezafibrate (BEZ), the pan-PPAR (peroxisome proliferator-activated receptor) activator, ameliorated diabetes in insulin deficient streptozotocin treated diabetic mice. In order to study whether BEZ can also improve glucose metabolism in a mouse model for fatty liver and type 2 diabetes, the drug was applied to TallyHo mice. METHODS TallyHo mice were divided into an early (ED) and late (LD) diabetes progression group and both groups were treated with 0.5% BEZ (BEZ group) or standard diet (SD group) for 8 weeks. We analyzed plasma parameters, pancreatic beta-cell morphology, and mass as well as glucose metabolism of the BEZ-treated and control mice. Furthermore, liver fat content and composition as well as hepatic gluconeogenesis and mitochondrial mass were determined. RESULTS Plasma lipid and glucose levels were markedly reduced upon BEZ treatment, which was accompanied by elevated insulin sensitivity index as well as glucose tolerance, respectively. BEZ increased islet area in the pancreas. Furthermore, BEZ treatment improved energy expenditure and metabolic flexibility. In the liver, BEZ ameliorated steatosis, modified lipid composition and increased mitochondrial mass, which was accompanied by reduced hepatic gluconeogenesis. CONCLUSIONS Our data showed that BEZ ameliorates diabetes probably via reduced steatosis, enhanced hepatic mitochondrial mass, improved metabolic flexibility and elevated hepatic insulin sensitivity in TallyHo mice, suggesting that BEZ treatment could be beneficial for patients with NAFLD and impaired glucose metabolism.
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Key Words
- BEZ, Bezafibrate
- BG, blood glucose
- Bezafibrate
- ED, early onset of diabetes
- EM, electron microscopy
- FA, fatty acid
- Glucose metabolism
- HOMA-IR, homeostatic model assessment of insulin resistance
- Insulin resistance
- LD, late onset of diabetes
- Lipid metabolism
- NAFLD
- NAFLD, non-alcoholic fatty liver disease
- NEFA, non-esterified fatty acid
- PPAR, peroxisome proliferator-activated receptor
- RER, respiratory exchange ratios
- SD, standard diet
- T2D, type 2 diabetes
- TG, triglyceride
- qNMR, quantitative nuclear magnetic resonance
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Activation of PPARγ2 by PPARγ1 through a functional PPRE in transdifferentiation of myoblasts to adipocytes induced by EPA. Cell Cycle 2016; 14:1830-41. [PMID: 25892270 DOI: 10.1080/15384101.2015.1033594] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
PPARγ and Wnt signaling are central positive and negative regulators of adipogenesis, respectively. Here we identified that, eicosapentaenoic acid (EPA) could effectively induce the transdifferentiation of myoblasts into adipocytes through modulation of both PPARγ expression and Wnt signaling. During the early stage of transdifferentiation, EPA activates PPARδ and PPARγ1, which in turn targets β-catenin to degradation and down-regulates Wnt/β-catenin signaling, such that the myogenic fate of myoblasts could be switched to adipogenesis. In addition, EPA up-regulates the expression of PPARγ1 by activating RXRα, then PPARγ1 binds to the functional peroxisome proliferator responsive element (PPRE) in the promoter of adipocyte-specific PPARγ2 to continuously activate the expression of PPARγ2 throughout the transdifferentiation process. Our data indicated that EPA acts as a dual-function stimulator of adipogenesis that both inhibits Wnt signaling and induces PPARγ2 expression to facilitate the transdifferentiation program, and the transcriptional activation of PPARγ2 by PPARγ1 is not only the key factor for the transdifferentiation of myoblasts to adipocytes, but also the crucial evidence for successful transdifferentiation. The present findings provided insight for the first time as to how EPA induces the transdifferentiation of myoblasts to adipocytes, but also provide new clues for strategies to prevent and treat some metabolic diseases.
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Key Words
- BSA, bovine serum albumin
- C/EBP, CCAAT/enhancer-binding protein
- DHA, docosahexaenoic acid
- DMEM, Dulbecco's modified Eagle's medium
- EPA, eicosapentaenoic acid
- IMF, intramuscular fat
- PPAR, peroxisome proliferator-activated receptor
- PPARγ1
- PPARγ2
- PPARδ
- PPRE, peroxisome proliferator responsive element
- PUFA, polyunsaturated fatty acids
- RXR, retinoid X receptor.
- Wnt/β-catenin signaling
- eicosapentaenoic acid
- transdifferentiation
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Glucagon-to-insulin ratio is pivotal for splanchnic regulation of FGF-21 in humans. Mol Metab 2015; 4:551-60. [PMID: 26266087 PMCID: PMC4529499 DOI: 10.1016/j.molmet.2015.06.001] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 05/31/2015] [Accepted: 06/05/2015] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND & AIMS Fibroblast growth factor 21 (FGF-21) is a liver-derived metabolic regulator induced by energy deprivation. However, its regulation in humans is incompletely understood. We addressed the origin and regulation of FGF-21 secretion in humans. METHODS By determination of arterial-to-venous differences over the liver and the leg during exercise, we evaluated the organ-specific secretion of FGF-21 in humans. By four different infusion models manipulating circulating glucagon and insulin, we addressed the interaction of these hormones on FGF-21 secretion in humans. RESULTS We demonstrate that the splanchnic circulation secretes FGF-21 at rest and that it is rapidly enhanced during exercise. In contrast, the leg does not contribute to the systemic levels of FGF-21. To unravel the mechanisms underlying the regulation of exercise-induced hepatic release of FGF-21, we manipulated circulating glucagon and insulin. These studies demonstrated that in humans glucagon stimulates splanchnic FGF-21 secretion whereas insulin has an inhibitory effect. CONCLUSIONS Collectively, our data reveal that 1) in humans, the splanchnic bed contributes to the systemic FGF-21 levels during rest and exercise; 2) under normo-physiological conditions FGF-21 is not released from the leg; 3) a dynamic interaction of glucagon-to-insulin ratio regulates FGF-21 secretion in humans.
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Alcoholic, Nonalcoholic, and Toxicant-Associated Steatohepatitis: Mechanistic Similarities and Differences. Cell Mol Gastroenterol Hepatol 2015; 1:356-367. [PMID: 28210688 PMCID: PMC5301292 DOI: 10.1016/j.jcmgh.2015.05.006] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 05/27/2015] [Indexed: 12/12/2022]
Abstract
Hepatic steatosis and steatohepatitis are common histologic findings that can be caused by multiple etiologies. The three most frequent causes for steatosis/steatohepatitis are alcohol (alcoholic steatohepatitis, ASH), obesity/metabolic syndrome (nonalcoholic steatohepatitis, NASH), and environmental toxicants (toxicant-associated steatohepatitis, TASH). Hepatic steatosis is an early occurrence in all three forms of liver disease, and they often share common pathways to disease progression/severity. Disease progression is a result of both direct effects on the liver as well as indirect alterations in other organs/tissues such as intestine, adipose tissue, and the immune system. Although the three liver diseases (ASH, NASH, and TASH) share many common pathogenic mechanisms, they also exhibit distinct differences. Both shared and divergent mechanisms can be potential therapeutic targets. This review provides an overview of selected important mechanistic similarities and differences in ASH, NASH, and TASH.
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Key Words
- ALD, alcoholic liver disease
- ALT, alanine aminotransferase
- ASH, alcoholic steatohepatitis
- AST, aspartate transaminase
- Alcoholic Steatohepatitis
- BMI, body mass index
- CYP2E1, cytochrome P450 isoform 2E1
- ECM, extracellular matrix
- ER, endoplasmic reticulum
- HCC, hepatocellular carcinoma
- HDAC, histone deacetylase
- HSC, hepatic stellate cell
- IL, interleukin
- LA, linoleic acid
- LPS, lipopolysaccharide
- Mechanisms
- NAFLD, nonalcoholic fatty liver disease
- NASH, nonalcoholic steatohepatitis
- NK, natural killer
- NKT, natural killer T
- Nonalcoholic Steatohepatitis
- OXLAM, oxidized linoleic acid metabolite
- PAI-1, plasminogen activator inhibitor-1
- PCB153, 2,2′,4,4′,5,5′-hexachlorobiphenyl
- PPAR, peroxisome proliferator-activated receptor
- RNS, reactive nitrogen species
- SNP, single-nucleotide polymorphism
- TAFLD, toxicant-associated fatty liver disease
- TASH, toxicant-associated steatohepatitis
- TCDD, 2,3,7,8-tetrachlorodibenzo-p-dioxin
- TH, helper T cell
- TLR, Toll-like receptor
- TNF, tumor necrosis factor
- Toxicant-Associated Steatohepatitis
- VA, U.S. Department of Veterans Affairs/Veterans Administration
- miR, microRNA
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Acute induction of uncoupling protein 1 by citrulline in cultured explants of white adipose tissue from lean and high-fat-diet-fed rats. Adipocyte 2015; 4:129-34. [PMID: 26167416 PMCID: PMC4497294 DOI: 10.4161/21623945.2014.989748] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 11/13/2014] [Accepted: 11/14/2014] [Indexed: 01/14/2023] Open
Abstract
A diet enriched with citrulline (CIT) reduces white adipose tissue (WAT) mass. We recently showed that CIT stimulated β-oxidation in rat WAT explants from young (2-4 months) but not old (25 months) rats. Here we show that both in old rats and high-fat-diet-fed young rats, uncoupling protein one (UCP1) mRNA and protein expressions were weaker than those in young control rats. Selectively in WAT from young rats, a 24h CIT treatment up-regulated expressions of UCP1, peroxisome proliferator-activated receptor-α (PPARα), PPARγ-coactivator-1-α and mitochondrial-transcription-factor-A whereas it down-regulated PPARγ2 gene expression, whatever the diet. These results suggest that CIT induces a new metabolic status in WAT, with increased β-oxidation and uncoupling of respiratory chain, resulting in energy expenditure that favors fat mass reduction.
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Key Words
- ARG, arginine
- ASL, argininosuccinate lyase
- ASS, argininosuccinate synthase
- BSA, bovine serum albumin
- CD, control diet
- CIT, citrulline
- CPT1-b, carnitine palmitoyl transferase 1-b
- EPI, epididymal
- HFD, high-fat-diet
- KREBS, Krebs Ringer Buffer Saline
- NEFA, non-esterified fatty acids
- NO, nitric oxide
- NOS, nitric oxide synthase
- PEPCK-C, cytosolic phosphoenolpyruvate carboxykinase
- PGC-1α, peroxisome proliferator-activated receptor gamma co-activator 1α
- PKA, protein kinase A
- PPAR, peroxisome proliferator-activated receptor
- RET, retroperitoneal
- TFAM, mitochondrial transcription factor A
- UCP1
- VLCAD, very long chain acyl-CoA dehydrogenase
- WAT, white adipose tissue
- adipose tissue
- browning
- citrulline
- fatty acids
- obesity
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Metabolic effects of intestinal absorption and enterohepatic cycling of bile acids. Acta Pharm Sin B 2015; 5:129-34. [PMID: 26579438 PMCID: PMC4629214 DOI: 10.1016/j.apsb.2015.01.001] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 12/30/2014] [Accepted: 01/04/2015] [Indexed: 12/13/2022] Open
Abstract
The classical functions of bile acids include acting as detergents to facilitate the digestion and absorption of nutrients in the gut. In addition, bile acids also act as signaling molecules to regulate glucose homeostasis, lipid metabolism and energy expenditure. The signaling potential of bile acids in compartments such as the systemic circulation is regulated in part by an efficient enterohepatic circulation that functions to conserve and channel the pool of bile acids within the intestinal and hepatobiliary compartments. Changes in hepatobiliary and intestinal bile acid transport can alter the composition, size, and distribution of the bile acid pool. These alterations in turn can have significant effects on bile acid signaling and their downstream metabolic targets. This review discusses recent advances in our understanding of the inter-relationship between the enterohepatic cycling of bile acids and the metabolic consequences of signaling via bile acid-activated receptors, such as farnesoid X nuclear receptor (FXR) and the G-protein-coupled bile acid receptor (TGR5).
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Key Words
- ACCII, acetyl-CoA carboxylase 2
- APO, apolipoproteins
- ASBT, apical sodium-dependent bile acid transporter
- BSEP, bile salt export pump
- Bile acids
- CYP7A1, cholesterol 7α-hydroxylase
- DIO2, deiodinase 2
- Energy homeostasis
- FAS, fatty acid synthase
- FGF, fibroblast growth factor
- FGFR4, fibroblast growth factor receptor 4
- FOXO1, forkhead box protein O1
- FXR, farnesoid X-receptor
- G6Pase, glucose-6-phosphatase
- GLP-1, glucagon-like polypeptide-1
- HNF4α, hepatocyte nuclear factor 4 alpha
- IBABP, ileal bile acid binding protein
- Intestine
- LDL, low density lipoprotein
- Lipid metabolism
- Liver
- NTCP, Na+-taurocholate transporting polypeptide
- OATP, organic anion transporting polypeptide
- OST, organic solute transporter
- PEPCK, phosphoenolpyruvate carboxykinase
- PGC1α, peroxisome proliferator-activated receptor gamma coactivator 1 alpha
- PPAR, peroxisome proliferator-activated receptor
- SHP, small heterodimer partner
- SREBP1c, sterol regulatory element binding protein-1c
- T4, thyroid hormone
- TGR5, G-protein-coupled bile acid receptor
- Transporters
- VLDL, very low density lipoprotein
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Mechanism of the development of nonalcoholic steatohepatitis after pancreaticoduodenectomy. BBA CLINICAL 2015; 3:168-74. [PMID: 26674248 PMCID: PMC4661550 DOI: 10.1016/j.bbacli.2015.02.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Revised: 02/05/2015] [Accepted: 02/10/2015] [Indexed: 02/08/2023]
Abstract
Background and aim It is recognized that nonalcoholic fatty liver disease (NAFLD), including nonalcoholic steatohepatitis (NASH), may develop after pancreaticoduodenectomy (PD). However, the mechanism of NASH development remains unclear. This study aimed to examine the changes in gene expression associated with NASH occurrence following PD. Methods The expression of genes related to fatty acid/triglyceride (FA/TG) metabolism and inflammatory signaling was examined using liver samples obtained from 7 post-PD NASH patients and compared with 6 healthy individuals and 32 conventional NASH patients. Results The livers of post-PD NASH patients demonstrated significant up-regulation of the genes encoding CD36, FA-binding proteins 1 and 4, acetyl-coenzyme A carboxylase α, diacylglycerol acyltransferase 2, and peroxisome proliferator-activated receptor (PPAR) γ compared with normal and conventional NASH livers. Although serum apolipoprotein B (ApoB) and TG were decreased in post-PD NASH patients, the mRNAs of ApoB and microsomal TG transfer protein were robustly increased, indicating impaired TG export from the liver as very-low-density lipoprotein (VLDL). Additionally, elevated mRNA levels of myeloid differentiation primary response 88 and superoxide dismutases in post-PD NASH livers suggested significant activation of innate immune response and augmentation of oxidative stress generation. Conclusions Enhanced FA uptake into hepatocytes and lipogenesis, up-regulation of PPARγ, and disruption of VLDL excretion into the circulation are possible mechanisms of steatogenesis after PD. General significance These results provide a basis for understanding the pathogenesis of NAFLD/NASH following PD. The mechanism of NASH development after pancreaticoduodenectomy (PD) was unclear. The gene expression involved in fatty acid uptake and lipogenesis was increased. PPARγ and its target genes were up-regulated in post-PD NASH livers. Impaired triglyceride excretion from the liver was suggested in post-PD NASH. This study proposes possible mechanisms of steatogenesis after PD.
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Key Words
- ACACA, acetyl-CoA carboxylase α
- ACACB, acetyl-CoA carboxylase β
- ACADM, medium-chain acyl-CoA dehydrogenase
- ACOX1, acyl-CoA oxidase 1
- ALT, alanine aminotransferase
- AST, aspartate aminotransferase
- ApoB, apolipoprotein B
- BMI, body mass index
- CAT, catalase
- CPT1A, carnitine palmitoyl-CoA transferase 1α
- CT, computed tomography
- CYBB, cytochrome b-245 β polypeptide
- CYP, cytochrome P450
- CoA, coenzyme A
- DGAT, diacylglycerol acyltransferase
- FA, fatty acid
- FABP, fatty acid-binding protein
- FASN, fatty acid synthase
- Fatty acid
- HADHA, hydroxyacyl-CoA dehydrogenase/3-ketoacyl-CoA thiolase/enoyl-CoA hydratase α
- HBV, hepatitis B virus
- HCV, hepatitis C virus
- HOMA-IR, homeostasis model assessment for insulin resistance
- LPS, lipopolysaccharide
- LXR, liver X receptor
- MCD, methionine- and choline-deficient diet
- MTTP, microsomal triglyceride transfer protein
- MYD88, myeloid differentiation primary response 88
- MyD88
- NAFLD, nonalcoholic fatty liver disease
- NAS, NAFLD activity score
- NASH
- NASH, nonalcoholic steatohepatitis
- PD, pancreaticoduodenectomy
- PPAR, peroxisome proliferator-activated receptor
- PPARGC, PPARγ co-activator
- Pancreaticoduodenectomy
- ROS, reactive oxygen species
- RXR, retinoid X receptor
- SCD, stearoyl-CoA desaturase
- SOD, superoxide dismutase
- SREBF1, sterol regulatory element-binding transcription factor 1
- TG, triglyceride
- TGFB1, transforming growth factor β1
- TLR, Toll-like receptor
- TNF, tumor necrosis factor α
- US, ultrasonography
- VLDL
- VLDL, very-low-density lipoprotein
- qPCR, quantitative polymerase chain reaction
- γGT, gamma-glutamyltransferase
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Medium-chain triglyceride supplementation under a low-carbohydrate formula is a promising therapy for adult-onset type II citrullinemia. Mol Genet Metab Rep 2014; 1:42-50. [PMID: 27896073 PMCID: PMC5121258 DOI: 10.1016/j.ymgmr.2013.12.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 12/13/2013] [Indexed: 12/01/2022] Open
Abstract
Background Citrin, encoded by SLC25A13, is a component of the malate-aspartate shuttle, which is the main NADH-transporting system in the liver. Citrin deficiency causes neonatal intrahepatic cholestasis (NICCD), which usually resolves within the first year of life. However, small numbers of adults with citrin deficiency develop hyperammonemic encephalopathy, adult-onset type II citrullinemia (CTLN2), which leads to death due to cerebral edema. Liver transplantation is the only definitive therapy for patients with CTLN2. We previously reported that a lactose (galactose)-restricted and medium-chain triglyceride (MCT)-supplemented formula is notably effective for patients with NICCD. Citrin deficiency may impair the glycolysis in hepatocytes because of an increase in the cytosolic NADH/NAD+ ratio, leading to an energy shortage. MCT administration can provide energy to hepatocytes and was expected to have a good effect on CTLN2. Methods An MCT supplementation therapy under a low-carbohydrate formula was administered to five patients with CTLN2. Four of the patients had episodes of hyperammonemic encephalopathy, and one patient had postprandial hyperammonemia with no symptoms. Results One of the patients displaying hyperammonemic encephalopathy completely recovered with all normal laboratory findings. Others notably improved in terms of clinical and or laboratory findings with no hyperammonemic symptoms; however, the patients displayed persistent mild citrullinemia and occasionally had postprandial mild hyperammonemia most likely due to an irreversible change in the liver. Conclusions An MCT supplement can provide energy to hepatocytes and promote hepatic lipogenesis, leading to a reduction in the cytosolic NADH/NAD+ ratio. MCT supplementation under a low-carbohydrate formula could be a promising therapy for CTLN2 and should also be used to prevent CTLN2 to avoid irreversible liver damage.
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Key Words
- ALP, serum alkali phosphatase
- ALT, alanine aminotransferase
- ASS1, argininosuccinate synthetase 1
- AST, aspartate aminotransferase
- Adult-onset type II citrullinemia (CTLN2)
- BMI, body mass index
- CTLN2, adult-onset type II citrullinemia
- ChE, cholinesterase
- Citrin deficiency
- LDH, lactate dehydrogenase
- MCFA, medium-chain free fatty acids
- MCT, medium-chain triglycerides
- Malate-aspartate shuttle
- Medium-chain triglycerides (MCT)
- NICCD, neonatal intrahepatic cholestasis
- Neonatal intrahepatic cholestasis (NICCD)
- PPAR, peroxisome proliferator-activated receptor
- PSTI, pancreatic secretory trypsin inhibitor
- SLC25A13
- TIBC, total iron-binding capacity
- UIBC, unsaturated iron-binding capacity
- γ-GTP, gamma-glutamyl transpeptidase
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Role of the circadian clock gene Per2 in adaptation to cold temperature. Mol Metab 2013; 2:184-93. [PMID: 24049733 DOI: 10.1016/j.molmet.2013.05.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 05/02/2013] [Accepted: 05/03/2013] [Indexed: 01/12/2023] Open
Abstract
Adaptive thermogenesis allows mammals to resist to cold. For instance, in brown adipose tissue (BAT) the facultative uncoupling of the proton gradient from ATP synthesis in mitochondria is used to generate systemic heat. However, this system necessitates an increase of the Uncoupling protein 1 (Ucp1) and its activation by free fatty acids. Here we show that mice without functional Period2 (Per2) were cold sensitive because their adaptive thermogenesis system was less efficient. Upon cold-exposure, Heat shock factor 1 (HSF1) induced Per2 in the BAT. Subsequently, PER2 as a co-activator of PPARα increased expression of Ucp1. PER2 also increased Fatty acid binding protein 3 (Fabp3), a protein important to transport free fatty acids from the plasma to mitochondria to activate UCP1. Hence, in BAT PER2 is important for the coordination of the molecular response of mice exposed to cold by synchronizing UCP1 expression and its activation.
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Key Words
- Adrβ3, beta-adrenergic receptor 3
- BAT, brown adipose tissue
- BMAL1, brain and muscle ARNT-like factor
- Brown adipose tissue
- CLOCK, circadian locomotor output cycles kaput
- ChIP, chromatin immunoprecipitation
- FABP3, fatty acid binding protein 3
- FFA, free fatty acids
- HSE, heat shock element
- HSF1, heat shock factor 1
- Humidity
- NPAS2, neuronal PAS-domain containing protein 2
- PGC-1, PPAR-coactivator -1
- PPAR, peroxisome proliferator-activated receptor
- PPRE, PPAR element
- Per2, Period2
- RXR, retinoid X receptor
- SCN, suprachiasmatic nuclei
- Season
- TAG, triglycerides
- UCP1, uncoupling protein 1
- WAT, white adipose tissue
- WT, wild-type
- ZT, zeitgeber time
- luc, luciferase
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Adipocyte pyruvate dehydrogenase kinase 4 expression is associated with augmented PPARγ upregulation in early-life programming of later obesity. FEBS Open Bio 2012; 2:32-6. [PMID: 23650578 PMCID: PMC3642103 DOI: 10.1016/j.fob.2012.02.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 02/14/2012] [Accepted: 02/17/2012] [Indexed: 01/08/2023] Open
Abstract
We studied adipocytes from 8-week-old control rat offspring (CON) or rat offspring subjected to maternal low (8%) protein (MLP) feeding during pregnancy/lactation, a procedure predisposing to obesity. Acute exposure to isoproterenol or adenosine enhanced PDK4 and PPARγ mRNA gene expression in CON and MLP adipocytes. Enhanced adipocyte Pdk4 expression correlated with increased PPARγ expression. Higher levels of PDK4 and PPARγ were observed in MLP adipocytes. SCD1 is a PPARγ target. Isoproterenol enhanced adipocyte PDK4 and SCD1 gene expression in parallel. This could reflect augmented PPARγ expression together with enhanced lipolytic stimulation to supply endogenous PPARγ ligands, allowing enhanced adipocyte PDK4 and SCD1 expression via PPARγ activation. In contrast, the effect of adenosine to increase PDK4 expression is independent of stimulation of lipolysis and, as SCD1 expression was unaffected by adenosine, unlikely to reflect PPARγ activation. Increased adipocyte expression of both PDK4 and SCD1 in the MLP model could participate as components of a "thrifty" phenotype, favouring the development of obesity.
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Key Words
- ADO, adenosine
- Adipose tissue
- BSA, bovine serum albumin
- CON, control
- HSL, hormone-sensitive lipase
- ISO, isoproterenol
- KRHB, Krebs–Ringer HEPES buffer
- Lipogenesis
- MLP, maternal low protein
- NEFA, non-esterified fatty acid
- PC, pyruvate carboxylase
- PDC, pyruvate dehydrogenase complex
- PDK, pyruvate dehydrogenase kinase
- PEPCK, phosphoenolpyruvate carboxykinase
- PPAR, peroxisome proliferator-activated receptor
- Programming
- Pyruvate dehydrogenase complex
- SCD, stearoyl-CoA desaturase
- TAG, triacylglycerol
- WAT, white adipose tissue
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