1
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Sharifi S, Yamamoto T, Zeug A, Elsner M, Avezov E, Mehmeti I. Non-esterified fatty acid palmitate facilitates oxidative endoplasmic reticulum stress and apoptosis of β-cells by upregulating ERO-1α expression. Redox Biol 2024; 73:103170. [PMID: 38692092 PMCID: PMC11070623 DOI: 10.1016/j.redox.2024.103170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 04/24/2024] [Accepted: 04/26/2024] [Indexed: 05/03/2024] Open
Abstract
Adipose tissue-derived non-esterified saturated long-chain fatty acid palmitate (PA) decisively contributes to β-cell demise in type 2 diabetes mellitus in part through the excessive generation of hydrogen peroxide (H2O2). The endoplasmic reticulum (ER) as the primary site of oxidative protein folding could represent a significant source of H2O2. Both ER-oxidoreductin-1 (ERO-1) isoenzymes, ERO-1α and ERO-1β, catalyse oxidative protein folding within the ER, generating equimolar amounts of H2O2 for every disulphide bond formed. However, whether ERO-1-derived H2O2 constitutes a potential source of cytotoxic luminal H2O2 under lipotoxic conditions is still unknown. Here, we demonstrate that both ERO-1 isoforms are expressed in pancreatic β-cells, but interestingly, PA only significantly induces ERO-1α. Its specific deletion significantly attenuates PA-mediated oxidative ER stress and subsequent β-cell death by decreasing PA-mediated ER-luminal and mitochondrial H2O2 accumulation, by counteracting the dysregulation of ER Ca2+ homeostasis, and by mitigating the reduction of mitochondrial membrane potential and lowered ATP content. Moreover, ablation of ERO-1α alleviated PA-induced hyperoxidation of the ER redox milieu. Importantly, ablation of ERO-1α did not affect the insulin secretory capacity, the unfolded protein response, or ER redox homeostasis under steady-state conditions. The involvement of ERO-1α-derived H2O2 in PA-mediated β-cell lipotoxicity was corroborated by the overexpression of a redox-active ERO-1α underscoring the proapoptotic activity of ERO-1α in pancreatic β-cells. Overall, our findings highlight the critical role of ERO-1α-derived H2O2 in lipotoxic ER stress and β-cell failure.
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Affiliation(s)
- Sarah Sharifi
- Institute of Clinical Biochemistry, Hannover Medical School, 30625, Hannover, Germany
| | - Tomoko Yamamoto
- Institute of Clinical Biochemistry, Hannover Medical School, 30625, Hannover, Germany
| | - Andre Zeug
- Institute for Neurophysiology, Hannover Medical School, 30625, Hannover, Germany
| | - Matthias Elsner
- Institute of Clinical Biochemistry, Hannover Medical School, 30625, Hannover, Germany
| | - Edward Avezov
- Department of Clinical Neurosciences and UK Dementia Research Institute, University of Cambridge, CB2 0AH Cambridge, UK
| | - Ilir Mehmeti
- Institute of Clinical Biochemistry, Hannover Medical School, 30625, Hannover, Germany.
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2
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Neiteler A, Palakkan AA, Gallagher KM, Ross JA. Oxidative stress and docosahexaenoic acid injury lead to increased necroptosis and ferroptosis in retinal pigment epithelium. Sci Rep 2023; 13:21143. [PMID: 38036571 PMCID: PMC10689458 DOI: 10.1038/s41598-023-47721-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 11/17/2023] [Indexed: 12/02/2023] Open
Abstract
Age-related macular degeneration (AMD) is a complex disease caused by different genetic and environmental risk factors leading to loss of cells in the central part of the retina. Oxidative stress appears to be an important environmental risk factor that contributes to both the initiation and progression of AMD. Retinal pigment epithelium (RPE) plays an important role in regulating oxidative stress in the retina and is one of the main retinal cell types affected in AMD. A main function of RPE is to phagocytose photoreceptor outer segments (POS) which are rich in the polyunsaturated fatty acid (PUFA) docosahexaenoic acid (DHA), making this cell type potentially more susceptible to oxidative stress-induced lipid peroxidation which can lead to cell death. RPE is known to undergo necrotic cell death in response to oxidative stress. The aim of this study was to determine if DHA in POS can increase oxidative damage to RPE. It was found that RPE undergo increased lipid peroxidation and decreased cell viability when stressed with hydrogen peroxide in combination with DHA or POS. H2O2-induced oxidative stress was found to cause both ferroptosis and necroptosis. However, the ferroptosis regulator acyl-CoA synthetase long-chain family member 4 (ACSL4) was found to be downregulated in RPE exposed to H2O2 and this effect was exacerbated when the RPE cells were simultaneously treated with DHA. Together, these results show a response of RPE when stressed which will likely be overwhelmed under disease conditions such as AMD resulting in cell death.
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Affiliation(s)
- Almar Neiteler
- Tissue Injury and Repair Group, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK.
| | - Anwar A Palakkan
- Immunology and Stem Cell Biology, Aravind Medical Research Foundation, Anna Nagar, Madurai, 625020, India
| | - Kevin M Gallagher
- Tissue Injury and Repair Group, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK
| | - James A Ross
- Tissue Injury and Repair Group, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK
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3
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Zhao C, Wu B, Li J, Jiang Q, Loor JJ, Liu M, Chen L, Zhu Y, Gao W, Du X, Song Y, Liu G, Lei L, Li X. AdipoRon alleviates fatty acid-induced lipid accumulation and mitochondrial dysfunction in bovine hepatocytes by promoting autophagy. J Dairy Sci 2023:S0022-0302(23)00295-3. [PMID: 37268562 DOI: 10.3168/jds.2022-22723] [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: 09/01/2022] [Accepted: 01/28/2023] [Indexed: 06/04/2023]
Abstract
During the transition period in dairy cows, high circulating concentrations of nonesterified fatty acids (NEFA) increase hepatic lipid deposits and are considered a major pathological factor for liver damage. We investigated whether AdipoRon, a synthetic small-molecule agonist of adiponectin receptors 1 and 2 shown to prevent liver lipid accumulation in nonruminants, could alleviate NEFA-induced lipid accumulation and mitochondrial dysfunction. Bovine hepatocytes were isolated from 5 healthy Holstein female newborn calves (1 d of age, 30-40 kg, fasting), and independently isolated hepatocytes from at least 3 different calves were used for each subsequent experiment. The composition and concentration of NEFA used in this study were selected according to hematological criteria of dairy cows with fatty liver or ketosis. First, hepatocytes were cultured with various concentrations of NEFA (0, 0.6, 1.2, or 2.4 mM) for 12 h. In a second experiment, hepatocytes were treated with AdipoRon at different concentrations (0, 5, 25, or 50 μM for 12 h) and times (25 μM for 0, 6, 12, or 24 h) with or without NEFA (1.2 mM) treatment. In the last experiment, hepatocytes were treated with AdipoRon (25 μM), NEFA (1.2 mM), or both for 12 h after treatment with or without the autophagy inhibitor chloroquine. Hepatocytes treated with NEFA had increased protein abundance of sterol regulatory element-binding protein 1c (SREBP-1c) and mRNA abundance of acetyl-CoA carboxylase 1 (ACACA), and decreased protein abundance of peroxisome proliferator-activated receptor α (PPARA), proliferator-activated receptor gamma coactivator-1 α (PGC-1α), mitofusin 2 (MFN2), cytochrome c oxidase subunit IV (COX IV), and mRNA abundance of carnitine palmitoyltransferase 1A (CPT1A), along with lower ATP concentrations. AdipoRon treatment reversed these effects, suggesting this compound had a positive effect on lipid metabolism and mitochondrial dysfunction during the NEFA challenge. In addition, upregulated expression of microtubule-associated protein 1 light chain 3-II (LC3-II, encoded by MAP1LC3) and downregulated expression of sequestosome-1 (SQSTM1, also called p62) indicated that AdipoRon enhanced autophagic activity in hepatocytes. The fact that chloroquine impeded the beneficial effects of AdipoRon on lipid accumulation and mitochondrial dysfunction suggested a direct role for autophagy during NEFA challenge. Our results suggest that autophagy is an important cellular mechanism to prevent NEFA-induced lipid accumulation and mitochondrial dysfunction in bovine hepatocytes, which is consistent with other studies. Overall, AdipoRon may represent a promising therapeutic agent to maintain hepatic lipid homeostasis and mitochondrial function in dairy cows during the transition period.
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Affiliation(s)
- Chenchen Zhao
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, Institute of Zoonosis, and College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Bing Wu
- Department of Neurosurgery, China-Japan Union Hospital of Jilin University, Changchun, 130000, Jilin, China
| | - Jinxia Li
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, Institute of Zoonosis, and College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Qianming Jiang
- Mammalian NutriPhysioGenomics, Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana 61801
| | - Juan J Loor
- Mammalian NutriPhysioGenomics, Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana 61801
| | - Menglin Liu
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, Institute of Zoonosis, and College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Linfang Chen
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, Institute of Zoonosis, and College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Yiwei Zhu
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, Institute of Zoonosis, and College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Wenwen Gao
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, Institute of Zoonosis, and College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Xiliang Du
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, Institute of Zoonosis, and College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Yuxiang Song
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, Institute of Zoonosis, and College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Guowen Liu
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, Institute of Zoonosis, and College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Lin Lei
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, Institute of Zoonosis, and College of Veterinary Medicine, Jilin University, Changchun 130062, China.
| | - Xinwei Li
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, Institute of Zoonosis, and College of Veterinary Medicine, Jilin University, Changchun 130062, China.
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4
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Perez-Serna AA, Dos Santos RS, Ripoll C, Nadal A, Eizirik DL, Marroqui L. BCL-XL Overexpression Protects Pancreatic β-Cells against Cytokine- and Palmitate-Induced Apoptosis. Int J Mol Sci 2023; 24:5657. [PMID: 36982731 PMCID: PMC10056015 DOI: 10.3390/ijms24065657] [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: 01/23/2023] [Revised: 03/08/2023] [Accepted: 03/10/2023] [Indexed: 03/18/2023] Open
Abstract
Diabetes is a chronic disease that affects glucose metabolism, either by autoimmune-driven β-cell loss or by the progressive loss of β-cell function, due to continued metabolic stresses. Although both α- and β-cells are exposed to the same stressors, such as proinflammatory cytokines and saturated free fatty acids (e.g., palmitate), only α-cells survive. We previously reported that the abundant expression of BCL-XL, an anti-apoptotic member of the BCL-2 family of proteins, is part of the α-cell defense mechanism against palmitate-induced cell death. Here, we investigated whether BCL-XL overexpression could protect β-cells against the apoptosis induced by proinflammatory and metabolic insults. For this purpose, BCL-XL was overexpressed in two β-cell lines-namely, rat insulinoma-derived INS-1E and human insulin-producing EndoC-βH1 cells-using adenoviral vectors. We observed that the BCL-XL overexpression in INS-1E cells was slightly reduced in intracellular Ca2+ responses and glucose-stimulated insulin secretion, whereas these effects were not observed in the human EndoC-βH1 cells. In INS-1E cells, BCL-XL overexpression partially decreased cytokine- and palmitate-induced β-cell apoptosis (around 40% protection). On the other hand, the overexpression of BCL-XL markedly protected EndoC-βH1 cells against the apoptosis triggered by these insults (>80% protection). Analysis of the expression of endoplasmic reticulum (ER) stress markers suggests that resistance to the cytokine and palmitate conferred by BCL-XL overexpression might be, at least in part, due to the alleviation of ER stress. Altogether, our data indicate that BCL-XL plays a dual role in β-cells, participating both in cellular processes related to β-cell physiology and in fostering survival against pro-apoptotic insults.
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Affiliation(s)
- Atenea A. Perez-Serna
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universidad Miguel Hernández de Elche, 03202 Elche, Alicante, Spain
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas, Instituto de Salud Carlos III, Spain
| | - Reinaldo S. Dos Santos
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universidad Miguel Hernández de Elche, 03202 Elche, Alicante, Spain
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas, Instituto de Salud Carlos III, Spain
| | - Cristina Ripoll
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universidad Miguel Hernández de Elche, 03202 Elche, Alicante, Spain
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas, Instituto de Salud Carlos III, Spain
| | - Angel Nadal
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universidad Miguel Hernández de Elche, 03202 Elche, Alicante, Spain
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas, Instituto de Salud Carlos III, Spain
| | - Decio L. Eizirik
- ULB Center for Diabetes Research, Medical Faculty, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Laura Marroqui
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universidad Miguel Hernández de Elche, 03202 Elche, Alicante, Spain
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas, Instituto de Salud Carlos III, Spain
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5
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Mottillo EP, Mladenovic-Lucas L, Zhang H, Zhou L, Kelly CV, Ortiz PA, Granneman JG. A FRET sensor for the real-time detection of long chain acyl-CoAs and synthetic ABHD5 ligands. CELL REPORTS METHODS 2023; 3:100394. [PMID: 36936069 PMCID: PMC10014278 DOI: 10.1016/j.crmeth.2023.100394] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 12/19/2022] [Accepted: 01/05/2023] [Indexed: 01/26/2023]
Abstract
Intracellular long-chain acyl-coenzyme As (LC-acyl-CoAs) are thought to be under tight spatial and temporal controls, yet the ability to image LC-acyl-CoAs in live cells is lacking. Here, we developed a fluorescence resonance energy transfer (FRET) sensor for LC-acyl-CoAs based on the allosterically regulated interaction between α/β hydrolase domain-containing 5 (ABHD5) and Perilipin 5. The genetically encoded sensor rapidly detects intracellular LC-acyl-CoAs generated from exogenous and endogenous fatty acids (FAs), as well as synthetic ABHD5 ligands. Stimulation of lipolysis in brown adipocytes elevated intracellular LC-acyl-CoAs in a cyclic fashion, which was eliminated by inhibiting PNPLA2 (ATGL), the major triglyceride lipase. Interestingly, inhibition of LC-acyl-CoA transport into mitochondria elevated intracellular LC-acyl-CoAs and dampened their cycling. Together, these observations reveal an intimate feedback control between LC-acyl-CoA generation from lipolysis and utilization in mitochondria. We anticipate that this sensor will be an important tool to dissect intracellular LC-acyl-CoA dynamics as well to discover novel synthetic ABHD5 ligands.
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Affiliation(s)
- Emilio P. Mottillo
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, 6135 Woodward Avenue, Detroit, MI 48202, USA
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Ljiljana Mladenovic-Lucas
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48202, USA
| | - Huamei Zhang
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48202, USA
| | - Li Zhou
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48202, USA
| | - Christopher V. Kelly
- Department of Physics and Astronomy, Wayne State University, Detroit, MI 48202, USA
| | - Pablo A. Ortiz
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, 6135 Woodward Avenue, Detroit, MI 48202, USA
| | - James G. Granneman
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48202, USA
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6
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Bianchetti G, Clementi ME, Sampaolese B, Serantoni C, Abeltino A, De Spirito M, Sasson S, Maulucci G. Metabolic Imaging and Molecular Biology Reveal the Interplay between Lipid Metabolism and DHA-Induced Modulation of Redox Homeostasis in RPE Cells. Antioxidants (Basel) 2023; 12:339. [PMID: 36829896 PMCID: PMC9952658 DOI: 10.3390/antiox12020339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/25/2023] [Accepted: 01/29/2023] [Indexed: 02/04/2023] Open
Abstract
Diabetes-induced oxidative stress induces the development of vascular complications, which are significant causes of morbidity and mortality in diabetic patients. Among these, diabetic retinopathy (DR) is often caused by functional changes in the blood-retinal barrier (BRB) due to harmful oxidative stress events in lipids, proteins, and DNA. Docosahexaenoic acid (DHA) has a potential therapeutic effect against hyperglycemia-induced oxidative damage and apoptotic pathways in the main constituents of BRB, retinal pigment epithelium cells (ARPE-19). Effective antioxidant response elicited by DHA is driven by the activation of the Nrf2/Nqo1 signaling cascade, which leads to the formation of NADH, a reductive agent found in the cytoplasm. Nrf2 also induces the expression of genes encoding enzymes involved in lipid metabolism. This study, therefore, aims at investigating the modulation of lipid metabolism induced by high-glucose (HG) on ARPE-19 cells through the integration of metabolic imaging and molecular biology to provide a comprehensive functional and molecular characterization of the mechanisms activated in the disease, as well the therapeutic role of DHA. This study shows that HG augments RPE metabolic processes by enhancing lipid metabolism, from fatty acid uptake and turnover to lipid biosynthesis and β-oxidation. DHA exerts its beneficial effect by ameliorating lipid metabolism and reducing the increased ROS production under HG conditions. This investigation may provide novel insight for formulating novel treatments for DR by targeting lipid metabolism pathways.
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Affiliation(s)
- Giada Bianchetti
- Department of Neuroscience, Biophysics Sections, Università Cattolica del Sacro Cuore, Largo Francesco Vito, 1, 00168 Rome, Italy
- Fondazione Policlinico Universitario "A. Gemelli" IRCCS, 00168 Rome, Italy
| | - Maria Elisabetta Clementi
- Institute of Chemical Sciences and Technologies "Giulio Natta" (SCITEC)-CNR, Largo Francesco Vito, 1, 00168 Rome, Italy
| | - Beatrice Sampaolese
- Institute of Chemical Sciences and Technologies "Giulio Natta" (SCITEC)-CNR, Largo Francesco Vito, 1, 00168 Rome, Italy
| | - Cassandra Serantoni
- Department of Neuroscience, Biophysics Sections, Università Cattolica del Sacro Cuore, Largo Francesco Vito, 1, 00168 Rome, Italy
- Fondazione Policlinico Universitario "A. Gemelli" IRCCS, 00168 Rome, Italy
| | - Alessio Abeltino
- Department of Neuroscience, Biophysics Sections, Università Cattolica del Sacro Cuore, Largo Francesco Vito, 1, 00168 Rome, Italy
- Fondazione Policlinico Universitario "A. Gemelli" IRCCS, 00168 Rome, Italy
| | - Marco De Spirito
- Department of Neuroscience, Biophysics Sections, Università Cattolica del Sacro Cuore, Largo Francesco Vito, 1, 00168 Rome, Italy
- Fondazione Policlinico Universitario "A. Gemelli" IRCCS, 00168 Rome, Italy
| | - Shlomo Sasson
- Faculty of Medicine, Institute for Drug Research, The Hebrew University, Jerusalem 911210, Israel
| | - Giuseppe Maulucci
- Department of Neuroscience, Biophysics Sections, Università Cattolica del Sacro Cuore, Largo Francesco Vito, 1, 00168 Rome, Italy
- Fondazione Policlinico Universitario "A. Gemelli" IRCCS, 00168 Rome, Italy
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7
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Vorotnikov AV, Khapchaev AY, Nickashin AV, Shirinsky VP. In Vitro Modeling of Diabetes Impact on Vascular Endothelium: Are Essentials Engaged to Tune Metabolism? Biomedicines 2022; 10:biomedicines10123181. [PMID: 36551937 PMCID: PMC9775148 DOI: 10.3390/biomedicines10123181] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 12/01/2022] [Accepted: 12/06/2022] [Indexed: 12/14/2022] Open
Abstract
Angiopathy is a common complication of diabetes mellitus. Vascular endothelium is among the first targets to experience blood-borne metabolic alterations, such as hyperglycemia and hyperlipidemia, the hallmarks of type 2 diabetes. To explore mechanisms of vascular dysfunction and eventual damage brought by these pathologic conditions and to find ways to protect vasculature in diabetic patients, various research approaches are used including in vitro endothelial cell-based models. We present an analysis of the data available from these models that identifies early endothelial cell apoptosis associated with oxidative stress as the major outcome of mimicking hyperglycemia and hyperlipidemia in vitro. However, the fate of endothelial cells observed in these studies does not closely follow it in vivo where massive endothelial damage occurs mainly in the terminal stages of diabetes and in conjunction with comorbidities. We propose that the discrepancy is likely in missing essentials that should be available to cultured endothelial cells to adjust the metabolic state and withstand the immediate apoptosis. We discuss the role of carnitine, creatine, and AMP-activated protein kinase (AMPK) in suiting the endothelial metabolism for long-term function in diabetic type milieu in vitro. Engagement of these essentials is anticipated to expand diabetes research options when using endothelial cell-based models.
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8
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Pieters V, Rjaibi ST, Singh K, Li NT, Khan ST, Nunes SS, Dal Cin A, Gilbert P, McGuigan AP. A three-dimensional human adipocyte model of fatty acid-induced obesity. Biofabrication 2022; 14. [PMID: 35896099 DOI: 10.1088/1758-5090/ac84b1] [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: 03/28/2022] [Accepted: 07/27/2022] [Indexed: 11/12/2022]
Abstract
Obesity prevalence has reached pandemic proportions, leaving individuals at high risk for the development of diseases such as cancer and type 2 diabetes. In obesity, to accommodate excess lipid storage, adipocytes become hypertrophic, which is associated with an increased pro-inflammatory cytokine secretion and dysfunction of metabolic processes such as insulin signaling and lipolysis. Targeting adipocyte dysfunction is an important strategy to prevent the development of obesity-associated disease. However, it is unclear how accurately animal models reflect human biology, and the long-term culture of human hypertrophic adipocytes in an in vitro 2D monolayer is challenging due to the buoyant nature of adipocytes. Here we describe the development of a human 3D in vitro disease model that recapitulates hallmarks of obese adipocyte dysfunction. First, primary human adipose-derived mesenchymal stromal cells are embedded in hydrogel, and infiltrated into a thin cellulose scaffold. The thin microtissue profile allows for efficient assembly and image-based analysis. After adipocyte differentiation, the scaffold is stimulated with oleic or palmitic acid to mimic caloric overload. Using functional assays, we demonstrated that this treatment induced important obese adipocyte characteristics such as a larger lipid droplet size, increased basal lipolysis, insulin resistance and a change in macrophage gene expression through adipocyte-conditioned media. This 3D disease model mimics physiologically relevant hallmarks of obese adipocytes, to enable investigations into the mechanisms by which dysfunctional adipocytes contribute to disease.
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Affiliation(s)
- Vera Pieters
- University of Toronto, 200 College Street, Toronto, Ontario, M5R3E5, CANADA
| | - Saifedine T Rjaibi
- University of Toronto, 200 College Street, Toronto, Ontario, M5R3E5, CANADA
| | - Kanwaldeep Singh
- University of Toronto, 200 College Street, Toronto, Ontario, M5R 3E5, CANADA
| | - Nancy T Li
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 1A1, CANADA
| | - Safwat T Khan
- University of Toronto, 200 College Street, Toronto, Ontario, M5R 3E5, CANADA
| | - Sara S Nunes
- University of Toronto, 200 College Street, Toronto, Ontario, M5R 3E5, CANADA
| | - Arianna Dal Cin
- McMaster University, 504-304 Victoria Ave North, Hamilton, Ontario, L8L 5G4, CANADA
| | - Penney Gilbert
- University of Toronto, 200 College Street, Toronto, Ontario, M5R 3E5, CANADA
| | - Alison P McGuigan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Office: WB338, Walberg Building,, 200 College Street,, Toronto, ON, M5S 3E5, Toronto, Ontario, M5S 1A1, CANADA
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9
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Stomatin modulates adipogenesis through the ERK pathway and regulates fatty acid uptake and lipid droplet growth. Nat Commun 2022; 13:4174. [PMID: 35854007 PMCID: PMC9296665 DOI: 10.1038/s41467-022-31825-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 07/01/2022] [Indexed: 11/08/2022] Open
Abstract
Regulation of fatty acid uptake, lipid production and storage, and metabolism of lipid droplets (LDs), is closely related to lipid homeostasis, adipocyte hypertrophy and obesity. We report here that stomatin, a major constituent of lipid raft, participates in adipogenesis and adipocyte maturation by modulating related signaling pathways. In adipocyte-like cells, increased stomatin promotes LD growth or enlargements by facilitating LD-LD fusion. It also promotes fatty acid uptake from extracellular environment by recruiting effector molecules, such as FAT/CD36 translocase, to lipid rafts to promote internalization of fatty acids. Stomatin transgenic mice fed with high-fat diet exhibit obesity, insulin resistance and hepatic impairments; however, such phenotypes are not seen in transgenic animals fed with regular diet. Inhibitions of stomatin by gene knockdown or OB-1 inhibit adipogenic differentiation and LD growth through downregulation of PPARγ pathway. Effects of stomatin on PPARγ involves ERK signaling; however, an alternate pathway may also exist. Stomatin is a component of lipid rafts. Here, Wu et al. show that stomatin modulates the differentiation and functions of adipocytes by regulating adipogenesis signaling and fatty acid influx such that with excessive calorie intake, increased stomatin induces adiposity.
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10
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Cyanidin-3-O-Glucoside Ameliorates Palmitic-Acid-Induced Pancreatic Beta Cell Dysfunction by Modulating CHOP-Mediated Endoplasmic Reticulum Stress Pathways. Nutrients 2022; 14:nu14091835. [PMID: 35565803 PMCID: PMC9103664 DOI: 10.3390/nu14091835] [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: 03/23/2022] [Revised: 04/23/2022] [Accepted: 04/24/2022] [Indexed: 11/17/2022] Open
Abstract
Cyanidin-3-O-glucoside (C3G) is a natural colorant with anti-diabetic properties, while its underlying mechanisms remain far from clear. Here, we investigated the protective role of C3G on palmitic acid (PA)-induced pancreatic beta cell dysfunction and further decipher its possible molecular mechanisms. Both primary isolated mouse islets and the INS-1E cell were used, and treated with a mixture of PA (0.5 mM) and C3G (12.5 µM, 25 µM, 50 µM) for different durations (12, 24, 48 h). We found that C3G could dose-dependently ameliorate beta cell secretory function and further alleviate cell apoptosis. Mechanistically, the primary role of the PKR-like ER kinase (PERK) endoplasmic reticulum (ER) stress pathway was detected by RNA sequencing, and the PERK-pathway-related protein expression, especially the pro-apoptotic marker C/EBP homologous protein (CHOP) expression, was significantly downregulated by C3G treatment. The critical role of CHOP in mediating the protective effect of C3G was further validated by small interfering RNA. Conclusively, C3G could ameliorate PA-induced pancreatic beta cell dysfunction targeting the CHOP-related ER stress pathway, which might be used as a nutritional intervention for the preservation of beta cell dysfunction in type 2 diabetes mellitus.
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11
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Shojai S, Haeri Rohani SA, Moosavi-Movahedi AA, Habibi-Rezaei M. Human serum albumin in neurodegeneration. Rev Neurosci 2022; 33:803-817. [PMID: 35363449 DOI: 10.1515/revneuro-2021-0165] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 03/02/2022] [Indexed: 11/15/2022]
Abstract
Serum albumin (SA) exists in relatively high concentrations, in close contact with most cells. However, in the adult brain, except for cerebrospinal fluid (CSF), SA concentration is relatively low. It is mainly produced in the liver to serve as the main protein of the blood plasma. In the plasma, it functions as a carrier, chaperon, antioxidant, source of amino acids, osmoregulator, etc. As a carrier, it facilitates the stable presence and transport of the hydrophobic and hydrophilic molecules, including free fatty acids, steroid hormones, medicines, and metal ions. As a chaperon, SA binds to and protects other proteins. As an antioxidant, thanks to a free sulfhydryl group (-SH), albumin is responsible for most antioxidant properties of plasma. These functions qualify SA as a major player in, and a mirror of, overall health status, aging, and neurodegeneration. The low concentration of SA is associated with cognitive deterioration in the elderly and negative prognosis in multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS). SA has been shown to be structurally modified in neurological conditions such as Alzheimer's disease (AD). During blood-brain barrier damage albumin enters the brain tissue and could trigger epilepsy and neurodegeneration. SA is able to bind to the precursor agent of the AD, amyloid-beta (Aβ), preventing its toxic effects in the periphery, and is being tested for treating this disease. SA therapy may also be effective in brain rejuvenation. In the current review, we will bring forward the prominent properties and roles of SA in neurodegeneration.
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Affiliation(s)
- Sajjad Shojai
- School of Biology, College of Science, University of Tehran, Tehran, Iran
| | | | | | - Mehran Habibi-Rezaei
- School of Biology, College of Science, University of Tehran, Tehran, Iran
- Nano-Biomedicine Center of Excellence, Nanoscience and Nanotechnology Research Center, University of Tehran, Tehran, Iran
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12
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Römer A, Rawat D, Linn T, Petry SF. Preparation of fatty acid solutions exerts significant impact on experimental outcomes in cell culture models of lipotoxicity. Biol Methods Protoc 2022; 7:bpab023. [PMID: 35036572 PMCID: PMC8754478 DOI: 10.1093/biomethods/bpab023] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 11/25/2021] [Accepted: 11/30/2021] [Indexed: 11/14/2022] Open
Abstract
Free fatty acids are essentially involved in the pathogenesis of chronic diseases such as diabetes mellitus, non-alcoholic fatty liver disease, and cardiovascular disease. They promote mitochondrial dysfunction, oxidative stress, respiratory chain uncoupling, and endoplasmic reticulum stress and modulate stress-sensitive pathways. These detrimental biological effects summarized as lipotoxicity mainly depend on fatty acid carbon chain length, degree of unsaturation, concentration, and treatment time. Preparation of fatty acid solutions involves dissolving and complexing. Solvent toxicity and concentration, amount of bovine serum albumin (BSA), and ratio of albumin to fatty acids can vary significantly between equal concentrations, mediating considerable harmful effects and/or interference with certain assays such as 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Herein, we studied the impact of commonly used solvents ethanol and dimethyl sulfoxide and varying concentrations of BSA directly and in solution with oleic acid on MTT to formazan conversion, adenosine triphosphate level, and insulin content and secretion of murine β-cell line MIN6 employing different treatment duration. Our data show that experimental outcomes and assay readouts can be significantly affected by mere preparation of fatty acid solutions and should thus be carefully considered and described in detail to ensure comparability and distinct evaluation of data.
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Affiliation(s)
- Axel Römer
- Clinical Research Unit, Center of Internal Medicine, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - Divya Rawat
- Clinical Research Unit, Center of Internal Medicine, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - Thomas Linn
- Clinical Research Unit, Center of Internal Medicine, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - Sebastian F Petry
- Clinical Research Unit, Center of Internal Medicine, Justus Liebig University Giessen, 35392 Giessen, Germany
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13
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Parthasarathy G, Malhi H. Assessment of Lipotoxic Endoplasmic Reticulum (ER) Stress in Nonalcoholic Steatohepatitis (NASH). Methods Mol Biol 2022; 2455:243-254. [PMID: 35212999 PMCID: PMC9333415 DOI: 10.1007/978-1-0716-2128-8_19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Hepatocyte lipotoxicity is a hallmark of nonalcoholic steatohepatitis (NASH), and lipid induced liver injury occurs, in part, via activation of endoplasmic reticulum (ER) stress. Consequently, the unfolded protein response (UPR) is initiated, driven by three key ER transmembrane proteins, resulting in downstream responses that are dynamic and interconnected. Thus, careful interrogation of these pathways is required to investigate the complex role of ER stress in NASH. Herein, we describe different mechanisms of, and in vitro assays for assessment of lipotoxic ER stress in mouse hepatocytes.
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Affiliation(s)
| | - Harmeet Malhi
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA.
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14
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Gut Metabolite Trimethylamine N-Oxide Protects INS-1 β-Cell and Rat Islet Function under Diabetic Glucolipotoxic Conditions. Biomolecules 2021; 11:biom11121892. [PMID: 34944536 PMCID: PMC8699500 DOI: 10.3390/biom11121892] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 12/11/2021] [Accepted: 12/14/2021] [Indexed: 12/14/2022] Open
Abstract
Serum accumulation of the gut microbial metabolite trimethylamine N-oxide (TMAO) is associated with high caloric intake and type 2 diabetes (T2D). Impaired pancreatic β-cell function is a hallmark of diet-induced T2D, which is linked to hyperglycemia and hyperlipidemia. While TMAO production via the gut microbiome-liver axis is well defined, its molecular effects on metabolic tissues are unclear, since studies in various tissues show deleterious and beneficial TMAO effects. We investigated the molecular effects of TMAO on functional β-cell mass. We hypothesized that TMAO may damage functional β-cell mass by inhibiting β-cell viability, survival, proliferation, or function to promote T2D pathogenesis. We treated INS-1 832/13 β-cells and primary rat islets with physiological TMAO concentrations and compared functional β-cell mass under healthy standard cell culture (SCC) and T2D-like glucolipotoxic (GLT) conditions. GLT significantly impeded β-cell mass and function by inducing oxidative and endoplasmic reticulum (ER) stress. TMAO normalized GLT-mediated damage in β-cells and primary islet function. Acute 40µM TMAO recovered insulin production, insulin granule formation, and insulin secretion by upregulating the IRE1α unfolded protein response to GLT-induced ER and oxidative stress. These novel results demonstrate that TMAO protects β-cell function and suggest that TMAO may play a beneficial molecular role in diet-induced T2D conditions.
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15
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Oemer G, Edenhofer ML, Wohlfarter Y, Lackner K, Leman G, Koch J, Cardoso LHD, Lindner HH, Gnaiger E, Dubrac S, Zschocke J, Keller MA. Fatty acyl availability modulates cardiolipin composition and alters mitochondrial function in HeLa cells. J Lipid Res 2021; 62:100111. [PMID: 34450173 PMCID: PMC8455370 DOI: 10.1016/j.jlr.2021.100111] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 08/18/2021] [Accepted: 08/20/2021] [Indexed: 12/19/2022] Open
Abstract
The molecular assembly of cells depends not only on the balance between anabolism and catabolism but to a large degree on the building blocks available in the environment. For cultured mammalian cells, this is largely determined by the composition of the applied growth medium. Here, we study the impact of lipids in the medium on mitochondrial membrane architecture and function by combining LC-MS/MS lipidomics and functional tests with lipid supplementation experiments in an otherwise serum-free and lipid-free cell culture model. We demonstrate that the composition of mitochondrial cardiolipins strongly depends on the lipid environment in cultured cells and favors the incorporation of essential linoleic acid over other fatty acids. Simultaneously, the mitochondrial respiratory complex I activity was altered, whereas the matrix-localized enzyme citrate synthase was unaffected. This raises the question on a link between membrane composition and respiratory control. In summary, we found a strong dependency of central mitochondrial features on the type of lipids contained in the growth medium. This underlines the importance of considering these factors when using and establishing cell culture models in biomedical research. In summary, we found a strong dependency of central mitochondrial features on the type of lipids contained in the growth medium.
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Affiliation(s)
- Gregor Oemer
- Institute of Human Genetics, Medical University of Innsbruck, Innsbruck, Austria
| | - Marie-Luise Edenhofer
- Institute of Human Genetics, Medical University of Innsbruck, Innsbruck, Austria; Institute of Physiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Yvonne Wohlfarter
- Institute of Human Genetics, Medical University of Innsbruck, Innsbruck, Austria
| | - Katharina Lackner
- Institute of Human Genetics, Medical University of Innsbruck, Innsbruck, Austria; Institute of Biological Chemistry, Biocenter Innsbruck, Medical University of Innsbruck, Innsbruck, Austria
| | - Geraldine Leman
- Epidermal Biology Laboratory, Department of Dermatology, Venereology and Allergology, Medical University of Innsbruck, Innsbruck, Austria
| | - Jakob Koch
- Institute of Human Genetics, Medical University of Innsbruck, Innsbruck, Austria
| | | | - Herbert H Lindner
- Institute of Clinical Biochemistry, Medical University of Innsbruck, Innsbruck, Austria
| | - Erich Gnaiger
- Oroboros Instruments Corporation, Innsbruck, Austria
| | - Sandrine Dubrac
- Epidermal Biology Laboratory, Department of Dermatology, Venereology and Allergology, Medical University of Innsbruck, Innsbruck, Austria
| | - Johannes Zschocke
- Institute of Human Genetics, Medical University of Innsbruck, Innsbruck, Austria
| | - Markus A Keller
- Institute of Human Genetics, Medical University of Innsbruck, Innsbruck, Austria.
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16
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Tardo-Dino PE, Taverny C, Siracusa J, Bourdon S, Baugé S, Koulmann N, Malgoyre A. Effect of heat acclimation on metabolic adaptations induced by endurance training in soleus rat muscle. Physiol Rep 2021; 9:e14686. [PMID: 34405575 PMCID: PMC8371354 DOI: 10.14814/phy2.14686] [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: 06/20/2020] [Revised: 10/19/2020] [Accepted: 10/29/2020] [Indexed: 11/24/2022] Open
Abstract
Aerobic training leads to well‐known systemic metabolic and muscular alterations. Heat acclimation may also increase mitochondrial muscle mass. We studied the effects of heat acclimation combined with endurance training on metabolic adaptations of skeletal muscle. Thirty‐two rats were divided into four groups: control (C), trained (T), heat‐acclimated (H), and trained with heat acclimation (H+T) for 6 weeks. Soleus muscle metabolism was studied, notably by the in situ measurement of mitochondrial respiration with pyruvate (Pyr) or palmitoyl‐coenzyme A (PCoA), under phosphorylating conditions (V˙max) or not (V˙0). Aerobic performance increased, and retroperitoneal fat mass decreased with training, independently of heat exposure (p < 0.001 and p < 0.001, respectively). Citrate synthase and hydroxyl‐acyl‐dehydrogenase activity increased with endurance training (p < 0.001 and p < 0.01, respectively), without any effect of heat acclimation. Training induced an increase of the V˙0 and V˙max for PCoA (p < .001 and p < .01, respectively), without interference with heat acclimation. The training‐induced increase of V˙0 (p < 0.01) for pyruvate oxidation was limited when combined with heat acclimation (−23%, p < 0.01). Training and heat acclimation independently increased the V˙max for pyruvate (+60% p < 0.001 and +50% p = 0.01, respectively), without an additive effect of the combination. Heat acclimation doubled the training effect on muscle glycogen storage (p < 0.001). Heat acclimation did not improve mitochondrial adaptations induced by endurance training in the soleus muscle, possibly limiting the alteration of carbohydrate oxidation while not facilitating fatty‐acid utilization. Furthermore, the increase in glycogen storage observed after HA combined with endurance training, without the improvement of pyruvate oxidation, appears to be a hypoxic metabolic phenotype.
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Affiliation(s)
- Pierre-Emmanuel Tardo-Dino
- Unité de Physiologie de l'Exercice et des Activités en Conditions Extrêmes, Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Brétigny sur Orge, France.,Ecole du Val-de-Grâce, Paris, France.,EDISS 205, Université Claude Bernard Lyon 1, Villeurbanne, France.,LBEPS, Université Evry, IRBA, Université Paris-Saclay, Paris, 91025, France
| | - Cindy Taverny
- Unité de Physiologie de l'Exercice et des Activités en Conditions Extrêmes, Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Brétigny sur Orge, France
| | - Julien Siracusa
- Unité de Physiologie de l'Exercice et des Activités en Conditions Extrêmes, Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Brétigny sur Orge, France.,LBEPS, Université Evry, IRBA, Université Paris-Saclay, Paris, 91025, France
| | - Stéphanie Bourdon
- Unité de Physiologie de l'Exercice et des Activités en Conditions Extrêmes, Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Brétigny sur Orge, France.,LBEPS, Université Evry, IRBA, Université Paris-Saclay, Paris, 91025, France
| | - Stéphane Baugé
- Unité de Physiologie de l'Exercice et des Activités en Conditions Extrêmes, Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Brétigny sur Orge, France.,LBEPS, Université Evry, IRBA, Université Paris-Saclay, Paris, 91025, France
| | - Nathalie Koulmann
- Unité de Physiologie de l'Exercice et des Activités en Conditions Extrêmes, Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Brétigny sur Orge, France.,Ecole du Val-de-Grâce, Paris, France.,EDISS 205, Université Claude Bernard Lyon 1, Villeurbanne, France.,LBEPS, Université Evry, IRBA, Université Paris-Saclay, Paris, 91025, France
| | - Alexandra Malgoyre
- Unité de Physiologie de l'Exercice et des Activités en Conditions Extrêmes, Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Brétigny sur Orge, France.,LBEPS, Université Evry, IRBA, Université Paris-Saclay, Paris, 91025, France
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17
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Tetraspanin TM4SF5 in hepatocytes negatively modulates SLC27A transporters during acute fatty acid supply. Arch Biochem Biophys 2021; 710:109004. [PMID: 34364885 DOI: 10.1016/j.abb.2021.109004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 08/03/2021] [Accepted: 08/04/2021] [Indexed: 12/12/2022]
Abstract
Transmembrane 4 L six family member 5 (TM4SF5) is involved in nonalcoholic steatosis and further aggravation of liver disease. However, its mechanism for regulating FA accumulation is unknown. We investigated how TM4SF5 in hepatocytes affected FA accumulation during acute FA supply. TM4SF5-expressing hepatocytes and mouse livers accumulated less FAs, compared with those of TM4SF5 deficiency or inactivation. Binding of TM4SF5 to SLC27A2 increased gradually upon acute FA treatment, whereas TM4SF5 constitutively bound SLC27A5. Suppression of either SLC27A2 or SLC27A5 in hepatocytes expressing TM4SF5 differentially modulated initial and maximal FA uptake levels for a fast turnover of fatty acid. Altogether, TM4SF5 negatively modulates FA accumulation into hepatocytes via association with the transporters for an energy homeostasis, when FA are supplied acutely.
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18
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Phitthayaphong P, Kumfu S, Chattipakorn N, Chattipakorn SC. Blockage of Fc Gamma Receptors Alleviates Neuronal and Microglial Toxicity Induced by Palmitic Acid. J Alzheimers Dis 2021; 82:1315-1332. [PMID: 34151811 DOI: 10.3233/jad-210417] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND Palmitic acid (PA) promotes brain pathologies including Alzheimer's disease (AD)-related proteins, neuroinflammation, and microglial activation. The activation of neurons and microglia via their Fc gamma receptors (FcγRs) results in producing inflammatory cytokines. OBJECTIVE To investigate the expression of FcγRs, FcγR signaling proteins, AD-related proteins, proinflammatory cytokines, and cell viability of neurons and microglia in association with PA exposure as well as the effects of FcγR blockade on these parameters in response to PA. METHODS 200 and 400μM PA-conjugated BSA were applied to SH-SY5Y and HMC3 cells for 24 h. For FcγR blockage experiment, both cells were exposed to FcγR blocker before receiving of 200 and 400μM of PA-conjugated BSA for 24 h. RESULTS PA significantly increased AD-related proteins, including Aβ and BACE1, as well as increasing TNFα, IL-1β, and IL-6 in SH-SY5Y and HMC3 cells. However, the p-Tau/Tau ratio was only increased in SH-SY5Y cells. These results were associated with an increase in FcγRs activation and a decrease in cell viability in both cell types. FcγRs blockage diminished the activation of FcγR in SH-SY5Y and HMC3 cells. Interestingly, blocking FcγRs before PA exposure reduced the increment of AD-related proteins, proinflammatory cytokines caused by PA. FcγRs blocking also inhibits cell death for 23%of SH-SY5Y cells and 64%of HMC3 cells, respectively. CONCLUSION These findings suggest that PA is a risk factor for AD via the increased AD-related pathologies, inflammation, FcγRs activation, and brain cell death, while FcγR blockage can alleviate these effects.
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Affiliation(s)
- Phansa Phitthayaphong
- Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand
| | - Sirinart Kumfu
- Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand
| | - Nipon Chattipakorn
- Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand
| | - Siriporn C Chattipakorn
- Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand.,Department of Oral Biology and Diagnostic Sciences, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
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A Comprehensive Spectroscopic Analysis of the Ibuprofen Binding with Human Serum Albumin, Part II. Sci Pharm 2021. [DOI: 10.3390/scipharm89030030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Human serum albumin (HSA) is the most abundant human plasma protein. HSA plays a crucial role in many binding endos- and exogenous substances, which affects their pharmacological effect. The innovative aspect of the study is not only the interaction of fatted (HSA) and defatted (dHSA) human serum albumin with ibuprofen (IBU), but the analysis of the influence of temperature on the structural modifications of albumin and the interaction between the drug and proteins from the temperature characteristic of near hypothermia (308 K) to the temperature reflecting inflammation in the body (312 K and 314 K). Ibuprofen is a non-steroidal anti-inflammatory drug. IBU is used to relieve acute pain, inflammation, and fever. To determine ibuprofen’s binding site in the tertiary structure of HSA and dHSA, fluorescence spectroscopy was used. On its basis, the fluorescent emissive spectra of albumin (5 × 10−6 mol/dm3) without and with the presence of ibuprofen (1 × 10−5–1 × 10−4 mol/dm3) was recorded. The IBU-HSA complex’s fluorescence was excited by radiation of wavelengths of λex 275 nm and λex 295 nm. Spectrophotometric spectroscopy allowed for recording the absorbance spectra (zero-order and second derivative absorption spectra) of HSA and dHSA under the influence of ibuprofen (1 × 10−4 mol/dm3). To characterize the changes of albumin structure the presence of IBU, circular dichroism was used. The data obtained show that the presence of fatty acids and human serum albumin temperature influences the strength and type of interaction between serum albumin and drug. Ibuprofen binds more strongly to defatted human serum albumin than to albumin in the presence of fatty acids. Additionally, stronger complexes are formed with increasing temperatures. The competitive binding of ibuprofen and fatty acids to albumin may influence the concentration of free drug fraction and thus its therapeutic effect.
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Tanshinone IIA Downregulates Lipogenic Gene Expression and Attenuates Lipid Accumulation through the Modulation of LXRα/SREBP1 Pathway in HepG2 Cells. Biomedicines 2021; 9:biomedicines9030326. [PMID: 33806955 PMCID: PMC8004631 DOI: 10.3390/biomedicines9030326] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 03/21/2021] [Accepted: 03/21/2021] [Indexed: 12/12/2022] Open
Abstract
Abnormal and excessive accumulation of lipid droplets within hepatic cells is the main feature of steatosis and nonalcoholic fatty liver disease (NAFLD) or metabolic-associated fatty liver disease (MAFLD). Dysregulation of lipogenesis contributes to hepatic steatosis and plays an essential role in the pathological progress of MAFLD. Tanshinone IIA is a bioactive phytochemical isolated from Salvia miltiorrhiza Bunge and exhibits anti-inflammatory, antiatherosclerotic and antihyperlipidemic effects. In this study, we aimed to investigate the lipid-lowering effects of tanshinone IIA on the regulation of lipogenesis, lipid accumulation, and the underlying mechanisms in hepatic cells. We demonstrated that tanshinone IIA can significantly inhibit the gene expression involved in de novo lipogenesis including FASN, ACC1, and SCD1, in HepG2 and Huh 7 cells. Tanshinone IIA could increase phosphorylation of ACC1 protein in HepG2 cells. We further demonstrated that tanshinone IIA also could suppress the fatty-acid-induced lipogenesis and TG accumulation in HepG2 cells. Furthermore, tanshinone IIA markedly downregulated the mRNA and protein expression of SREBP1, an essential transcription factor regulating lipogenesis in hepatic cells. Moreover, we found that tanshinone IIA attenuated liver X receptor α (LXRα)-mediated lipogenic gene expression and lipid droplet accumulation, but did not change the levels of LXRα mRNA or protein in HepG2 cells. The molecular docking data predicted tanshinone IIA binding to the ligand-binding domain of LXRα, which may result in the attenuation of LXRα-induced transcriptional activation. Our findings support the supposition that tanshinone IIA possesses a lipid-modulating effect that suppresses lipogenesis and attenuates lipid accumulation by modulating the LXRα/SREBP1 pathway in hepatic cells. Tanshinone IIA can be potentially used as a supplement or drug for the prevention or treatment of MAFLD.
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21
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Lipotoxic Impairment of Mitochondrial Function in β-Cells: A Review. Antioxidants (Basel) 2021; 10:antiox10020293. [PMID: 33672062 PMCID: PMC7919463 DOI: 10.3390/antiox10020293] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 02/06/2021] [Accepted: 02/11/2021] [Indexed: 02/08/2023] Open
Abstract
Lipotoxicity is a major contributor to type 2 diabetes mainly promoting mitochondrial dysfunction. Lipotoxic stress is mediated by elevated levels of free fatty acids through various mechanisms and pathways. Impaired peroxisome proliferator-activated receptor (PPAR) signaling, enhanced oxidative stress levels, and uncoupling of the respiratory chain result in ATP deficiency, while β-cell viability can be severely impaired by lipotoxic modulation of PI3K/Akt and mitogen-activated protein kinase (MAPK)/extracellular-signal-regulated kinase (ERK) pathways. However, fatty acids are physiologically required for an unimpaired β-cell function. Thus, preparation, concentration, and treatment duration determine whether the outcome is beneficial or detrimental when fatty acids are employed in experimental setups. Further, ageing is a crucial contributor to β-cell decay. Cellular senescence is connected to loss of function in β-cells and can further be promoted by lipotoxicity. The potential benefit of nutrients has been broadly investigated, and particularly polyphenols were shown to be protective against both lipotoxicity and cellular senescence, maintaining the physiology of β-cells. Positive effects on blood glucose regulation, mitigation of oxidative stress by radical scavenging properties or regulation of antioxidative enzymes, and modulation of apoptotic factors were reported. This review summarizes the significance of lipotoxicity and cellular senescence for mitochondrial dysfunction in the pancreatic β-cell and outlines potential beneficial effects of plant-based nutrients by the example of polyphenols.
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22
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Marselli L, Piron A, Suleiman M, Colli ML, Yi X, Khamis A, Carrat GR, Rutter GA, Bugliani M, Giusti L, Ronci M, Ibberson M, Turatsinze JV, Boggi U, De Simone P, De Tata V, Lopes M, Nasteska D, De Luca C, Tesi M, Bosi E, Singh P, Campani D, Schulte AM, Solimena M, Hecht P, Rady B, Bakaj I, Pocai A, Norquay L, Thorens B, Canouil M, Froguel P, Eizirik DL, Cnop M, Marchetti P. Persistent or Transient Human β Cell Dysfunction Induced by Metabolic Stress: Specific Signatures and Shared Gene Expression with Type 2 Diabetes. Cell Rep 2020; 33:108466. [PMID: 33264613 DOI: 10.1016/j.celrep.2020.108466] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 08/06/2020] [Accepted: 11/10/2020] [Indexed: 12/16/2022] Open
Abstract
Pancreatic β cell failure is key to type 2 diabetes (T2D) onset and progression. Here, we assess whether human β cell dysfunction induced by metabolic stress is reversible, evaluate the molecular pathways underlying persistent or transient damage, and explore the relationships with T2D islet traits. Twenty-six islet preparations are exposed to several lipotoxic/glucotoxic conditions, some of which impair insulin release, depending on stressor type, concentration, and combination. The reversal of dysfunction occurs after washout for some, although not all, of the lipoglucotoxic insults. Islet transcriptomes assessed by RNA sequencing and expression quantitative trait loci (eQTL) analysis identify specific pathways underlying β cell failure and recovery. Comparison of a large number of human T2D islet transcriptomes with those of persistent or reversible β cell lipoglucotoxicity show shared gene expression signatures. The identification of mechanisms associated with human β cell dysfunction and recovery and their overlap with T2D islet traits provide insights into T2D pathogenesis, fostering the development of improved β cell-targeted therapeutic strategies.
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Affiliation(s)
- Lorella Marselli
- Department of Clinical and Experimental Medicine, and AOUP Cisanello University Hospital, University of Pisa, Pisa 56126, Italy.
| | - Anthony Piron
- ULB Center for Diabetes Research, Université Libre de Bruxelles, Brussels 1070, Belgium
| | - Mara Suleiman
- Department of Clinical and Experimental Medicine, and AOUP Cisanello University Hospital, University of Pisa, Pisa 56126, Italy
| | - Maikel L Colli
- ULB Center for Diabetes Research, Université Libre de Bruxelles, Brussels 1070, Belgium
| | - Xiaoyan Yi
- ULB Center for Diabetes Research, Université Libre de Bruxelles, Brussels 1070, Belgium
| | - Amna Khamis
- INSERM UMR 1283, CNRS UMR 8199, European Genomic Institute for Diabetes (EGID), Institut Pasteur de Lille, University of Lille, Lille University Hospital, Lille 59000, France
| | - Gaelle R Carrat
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology, and Metabolism, Imperial College, London, UK
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology, and Metabolism, Imperial College, London, UK; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Marco Bugliani
- Department of Clinical and Experimental Medicine, and AOUP Cisanello University Hospital, University of Pisa, Pisa 56126, Italy
| | - Laura Giusti
- Department of Clinical and Experimental Medicine, and AOUP Cisanello University Hospital, University of Pisa, Pisa 56126, Italy; School of Pharmacy, University of Camerino, Camerino, Italy
| | - Maurizio Ronci
- Department of Pharmacy, University "G. d'Annunzio" of Chieti-Pescara, Chieti, Italy; Centre for Advanced Studies and Technologies (CAST), University "G. d'Annunzio" of Chieti-Pescara, Chieti, Italy
| | - Mark Ibberson
- Vital-IT Group, Swiss Institute of Bioinformatics, Lausanne 1015, Switzerland
| | | | - Ugo Boggi
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa 56126, Italy; Division of General and Transplant Surgery, Cisanello University Hospital, Pisa 56124, Italy
| | - Paolo De Simone
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa 56126, Italy; Division of Liver Surgery and Transplantation, Cisanello University Hospital, Pisa 56124, Italy
| | - Vincenzo De Tata
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa 56126, Italy
| | - Miguel Lopes
- ULB Center for Diabetes Research, Université Libre de Bruxelles, Brussels 1070, Belgium
| | - Daniela Nasteska
- ULB Center for Diabetes Research, Université Libre de Bruxelles, Brussels 1070, Belgium
| | - Carmela De Luca
- Department of Clinical and Experimental Medicine, and AOUP Cisanello University Hospital, University of Pisa, Pisa 56126, Italy
| | - Marta Tesi
- Department of Clinical and Experimental Medicine, and AOUP Cisanello University Hospital, University of Pisa, Pisa 56126, Italy
| | - Emanuele Bosi
- Department of Clinical and Experimental Medicine, and AOUP Cisanello University Hospital, University of Pisa, Pisa 56126, Italy
| | - Pratibha Singh
- ULB Center for Diabetes Research, Université Libre de Bruxelles, Brussels 1070, Belgium
| | - Daniela Campani
- Department of Surgical, Medical and Molecular Pathology and the Critical Areas, University of Pisa, Pisa 56126, Italy
| | - Anke M Schulte
- Sanofi-Aventis Deutschland GmbH, Diabetes Research, Frankfurt, Germany
| | - Michele Solimena
- Paul Langerhans Institute Dresden of the Helmholtz Center Munich at University Hospital Carl Gustav Carus and Faculty of Medicine, TU Dresden, Dresden 01307, Germany; German Center for Diabetes Research (DZD e.V.), Neuherberg 85764, Germany
| | - Peter Hecht
- Sanofi-Aventis Deutschland GmbH, Diabetes Research, Frankfurt, Germany
| | | | | | | | | | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Mickaël Canouil
- INSERM UMR 1283, CNRS UMR 8199, European Genomic Institute for Diabetes (EGID), Institut Pasteur de Lille, University of Lille, Lille University Hospital, Lille 59000, France
| | - Philippe Froguel
- Department of Metabolism, Digestion, and Reproduction, Imperial College London, London, UK
| | - Decio L Eizirik
- ULB Center for Diabetes Research, Université Libre de Bruxelles, Brussels 1070, Belgium; WELBIO, Université Libre de Bruxelles, Brussels, Belgium; Indiana Biosciences Research Institute, Indianapolis, IN, USA; Division of Endocrinology, ULB Erasmus Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Miriam Cnop
- ULB Center for Diabetes Research, Université Libre de Bruxelles, Brussels 1070, Belgium; Division of Endocrinology, ULB Erasmus Hospital, Université Libre de Bruxelles, Brussels, Belgium.
| | - Piero Marchetti
- Department of Clinical and Experimental Medicine, and AOUP Cisanello University Hospital, University of Pisa, Pisa 56126, Italy.
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23
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Motlagh Scholle L, Schieffers H, Al-Robaiy S, Thaele A, Lehmann Urban D, Zierz S. Palmitate but Not Oleate Exerts a Negative Effect on Oxygen Utilization in Myoblasts of Patients with the m.3243A>G Mutation: A Pilot Study. Life (Basel) 2020; 10:life10090204. [PMID: 32947855 PMCID: PMC7555433 DOI: 10.3390/life10090204] [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: 08/05/2020] [Revised: 09/04/2020] [Accepted: 09/15/2020] [Indexed: 01/20/2023] Open
Abstract
It is known that exposure to excess saturated fatty acids, especially palmitate, can trigger cellular stress responses interpreted as lipotoxicity. The effect of excessive free fatty acids on oxidative phosphorylation capacity in myoblasts of patients with the m.3243A>G mutation was evaluated with the mitochondrial (Mito) stress test using a Seahorse XF96 analyzer. ß-oxidation, measured with the Seahorse XF96 analyzer, was similar in patients and controls, and reduced in both patients and controls at 40 °C compared to 37 °C. Mito stress test in the absence of fatty acids showed lower values in patients compared to controls. The mitochondrial activity and ATP production rates were significantly reduced in presence of palmitate, but not of oleate in patients, showing a negative effect of excessive palmitate on mitochondrial function in patients. Diabetes mellitus is a frequent symptom in patients with m.3243A>G mutation. It can be speculated that the negative effect of palmitate on mitochondrial function might be related to diacylglycerols (DAG) and ceramides (CER) mediated insulin resistance. This might contribute to the elevated risk for diabetes mellitus in m.3243A>G patients.
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Affiliation(s)
- Leila Motlagh Scholle
- Department of Neurology, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany; (H.S.); (A.T.); (S.Z.)
- Correspondence: ; Tel.: +49-345-557-3628; Fax: +49-345-557-3505
| | - Helena Schieffers
- Department of Neurology, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany; (H.S.); (A.T.); (S.Z.)
| | - Samiya Al-Robaiy
- Center for Basic Medical Research, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany;
| | - Annemarie Thaele
- Department of Neurology, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany; (H.S.); (A.T.); (S.Z.)
| | | | - Stephan Zierz
- Department of Neurology, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany; (H.S.); (A.T.); (S.Z.)
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24
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Lytrivi M, Ghaddar K, Lopes M, Rosengren V, Piron A, Yi X, Johansson H, Lehtiö J, Igoillo-Esteve M, Cunha DA, Marselli L, Marchetti P, Ortsäter H, Eizirik DL, Cnop M. Combined transcriptome and proteome profiling of the pancreatic β-cell response to palmitate unveils key pathways of β-cell lipotoxicity. BMC Genomics 2020; 21:590. [PMID: 32847508 PMCID: PMC7448506 DOI: 10.1186/s12864-020-07003-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 08/19/2020] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Prolonged exposure to elevated free fatty acids induces β-cell failure (lipotoxicity) and contributes to the pathogenesis of type 2 diabetes. In vitro exposure of β-cells to the saturated free fatty acid palmitate is a valuable model of lipotoxicity, reproducing features of β-cell failure observed in type 2 diabetes. In order to map the β-cell response to lipotoxicity, we combined RNA-sequencing of palmitate-treated human islets with iTRAQ proteomics of insulin-secreting INS-1E cells following a time course exposure to palmitate. RESULTS Crossing transcriptome and proteome of palmitate-treated β-cells revealed 85 upregulated and 122 downregulated genes at both transcript and protein level. Pathway analysis identified lipid metabolism, oxidative stress, amino-acid metabolism and cell cycle pathways among the most enriched palmitate-modified pathways. Palmitate induced gene expression changes compatible with increased free fatty acid mitochondrial import and β-oxidation, decreased lipogenesis and modified cholesterol transport. Palmitate modified genes regulating endoplasmic reticulum (ER) function, ER-to-Golgi transport and ER stress pathways. Furthermore, palmitate modulated cAMP/protein kinase A (PKA) signaling, inhibiting expression of PKA anchoring proteins and downregulating the GLP-1 receptor. SLC7 family amino-acid transporters were upregulated in response to palmitate but this induction did not contribute to β-cell demise. To unravel critical mediators of lipotoxicity upstream of the palmitate-modified genes, we identified overrepresented transcription factor binding sites and performed network inference analysis. These identified LXR, PPARα, FOXO1 and BACH1 as key transcription factors orchestrating the metabolic and oxidative stress responses to palmitate. CONCLUSIONS This is the first study to combine transcriptomic and sensitive time course proteomic profiling of palmitate-exposed β-cells. Our results provide comprehensive insight into gene and protein expression changes, corroborating and expanding beyond previous findings. The identification of critical drivers and pathways of the β-cell lipotoxic response points to novel therapeutic targets for type 2 diabetes.
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Affiliation(s)
- Maria Lytrivi
- ULB Center for Diabetes Research, Université Libre de Bruxelles, CP-618, Route de Lennik 808, 1070, Brussels, Belgium.,Division of Endocrinology, Erasmus Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Kassem Ghaddar
- ULB Center for Diabetes Research, Université Libre de Bruxelles, CP-618, Route de Lennik 808, 1070, Brussels, Belgium
| | - Miguel Lopes
- ULB Center for Diabetes Research, Université Libre de Bruxelles, CP-618, Route de Lennik 808, 1070, Brussels, Belgium
| | - Victoria Rosengren
- Diabetes Research Unit, Department of Clinical Science and Education, Sodersjukhuset, Karolinska Institutet, Stockholm, Sweden
| | - Anthony Piron
- ULB Center for Diabetes Research, Université Libre de Bruxelles, CP-618, Route de Lennik 808, 1070, Brussels, Belgium
| | - Xiaoyan Yi
- ULB Center for Diabetes Research, Université Libre de Bruxelles, CP-618, Route de Lennik 808, 1070, Brussels, Belgium
| | - Henrik Johansson
- Clinical Proteomics Mass Spectrometry, Department of Oncology-Pathology, Karolinska Institutet, Science for Life Laboratory, 171 21, Solna, Sweden
| | - Janne Lehtiö
- Clinical Proteomics Mass Spectrometry, Department of Oncology-Pathology, Karolinska Institutet, Science for Life Laboratory, 171 21, Solna, Sweden
| | - Mariana Igoillo-Esteve
- ULB Center for Diabetes Research, Université Libre de Bruxelles, CP-618, Route de Lennik 808, 1070, Brussels, Belgium
| | - Daniel A Cunha
- ULB Center for Diabetes Research, Université Libre de Bruxelles, CP-618, Route de Lennik 808, 1070, Brussels, Belgium
| | - Lorella Marselli
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Piero Marchetti
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Henrik Ortsäter
- Diabetes Research Unit, Department of Clinical Science and Education, Sodersjukhuset, Karolinska Institutet, Stockholm, Sweden
| | - Decio L Eizirik
- ULB Center for Diabetes Research, Université Libre de Bruxelles, CP-618, Route de Lennik 808, 1070, Brussels, Belgium
| | - Miriam Cnop
- ULB Center for Diabetes Research, Université Libre de Bruxelles, CP-618, Route de Lennik 808, 1070, Brussels, Belgium. .,Division of Endocrinology, Erasmus Hospital, Université Libre de Bruxelles, Brussels, Belgium.
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25
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Alarcón P, Manosalva C, Quiroga J, Belmar I, Álvarez K, Díaz G, Taubert A, Hermosilla C, Carretta MD, Burgos RA, Hidalgo MA. Oleic and Linoleic Acids Induce the Release of Neutrophil Extracellular Traps via Pannexin 1-Dependent ATP Release and P2X1 Receptor Activation. Front Vet Sci 2020; 7:260. [PMID: 32582772 PMCID: PMC7291836 DOI: 10.3389/fvets.2020.00260] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 04/17/2020] [Indexed: 12/13/2022] Open
Abstract
Non-esterified fatty acids (NEFAs) such as oleic acid (OA) and linoleic acid (LA) are associated with a higher incidence of infectious diseases such as metritis and mastitis during the bovine peripartum. Fatty acids can induce an increase in the release of ATP, and changes in the expression levels of purinergic receptors in bovine polymorphonuclears (PMN) during peripartum have also been reported. PMN respond to inflammatory processes with production of ROS, release of proteolytic and bactericidal proteins, and formation of neutrophil extracellular traps (NETs). NETs formation is known to require ATP production through glycolysis. Studies have shown that the above-mentioned metabolic changes alter innate immune responses, particularly in PMN. We hypothesized that NEFAs induce the formation of NETs through ATP release by Pannexin 1 and activation of purinergic receptors. In this study, we found that OA and LA induce NET formation and extracellular ATP release. Carbenoxolone, a pannexin-1 (PANX1) inhibitor, reduced OA- and LA-induced ATP release. We also found that P2X1, P2X4, P2X5, P2X7, and PANX1 were expressed at the mRNA level in bovine PMN. Additionally, NEFA-induced NET formation was completely abolished with exposure to NF449, a P2X1 antagonist, and partially inhibited by treatment with etomoxir, an inhibitor of fatty acid oxidation (FAO). Our results suggest that OA and LA induce NET formation and ATP release via PANX1 and activation of P2X1. These new data contribute to explaining the effects of NEFA high concentrations during the transition period of dairy cattle and further understanding of pro-inflammatory effects and outcome of postpartum diseases.
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Affiliation(s)
- Pablo Alarcón
- Laboratory of Inflammation Pharmacology, Faculty of Veterinary Sciences, Institute of Pharmacology and Morphophysiology, Universidad Austral de Chile, Valdivia, Chile.,Laboratory of Immunometabolism, Faculty of Veterinary Sciences, Institute of Pharmacology and Morphophysiology, Universidad Austral de Chile, Valdivia, Chile
| | - Carolina Manosalva
- Faculty of Sciences, Institute of Pharmacy, Universidad Austral de Chile, Valdivia, Chile
| | - John Quiroga
- Laboratory of Inflammation Pharmacology, Faculty of Veterinary Sciences, Institute of Pharmacology and Morphophysiology, Universidad Austral de Chile, Valdivia, Chile.,Laboratory of Immunometabolism, Faculty of Veterinary Sciences, Institute of Pharmacology and Morphophysiology, Universidad Austral de Chile, Valdivia, Chile.,Faculty of Veterinary Sciences, Universidad Austral de Chile, Valdivia, Chile
| | - Isidora Belmar
- Laboratory of Inflammation Pharmacology, Faculty of Veterinary Sciences, Institute of Pharmacology and Morphophysiology, Universidad Austral de Chile, Valdivia, Chile.,Laboratory of Immunometabolism, Faculty of Veterinary Sciences, Institute of Pharmacology and Morphophysiology, Universidad Austral de Chile, Valdivia, Chile
| | - Karina Álvarez
- Laboratory of Inflammation Pharmacology, Faculty of Veterinary Sciences, Institute of Pharmacology and Morphophysiology, Universidad Austral de Chile, Valdivia, Chile.,Laboratory of Immunometabolism, Faculty of Veterinary Sciences, Institute of Pharmacology and Morphophysiology, Universidad Austral de Chile, Valdivia, Chile
| | - Gustavo Díaz
- Laboratory of Inflammation Pharmacology, Faculty of Veterinary Sciences, Institute of Pharmacology and Morphophysiology, Universidad Austral de Chile, Valdivia, Chile.,Laboratory of Immunometabolism, Faculty of Veterinary Sciences, Institute of Pharmacology and Morphophysiology, Universidad Austral de Chile, Valdivia, Chile
| | - Anja Taubert
- Institute of Parasitology, Biomedical Research Center Seltersberg, Justus Liebig University Giessen, Giessen, Germany
| | - Carlos Hermosilla
- Institute of Parasitology, Biomedical Research Center Seltersberg, Justus Liebig University Giessen, Giessen, Germany
| | - María D Carretta
- Laboratory of Inflammation Pharmacology, Faculty of Veterinary Sciences, Institute of Pharmacology and Morphophysiology, Universidad Austral de Chile, Valdivia, Chile.,Laboratory of Immunometabolism, Faculty of Veterinary Sciences, Institute of Pharmacology and Morphophysiology, Universidad Austral de Chile, Valdivia, Chile
| | - Rafael A Burgos
- Laboratory of Inflammation Pharmacology, Faculty of Veterinary Sciences, Institute of Pharmacology and Morphophysiology, Universidad Austral de Chile, Valdivia, Chile.,Laboratory of Immunometabolism, Faculty of Veterinary Sciences, Institute of Pharmacology and Morphophysiology, Universidad Austral de Chile, Valdivia, Chile
| | - María A Hidalgo
- Laboratory of Inflammation Pharmacology, Faculty of Veterinary Sciences, Institute of Pharmacology and Morphophysiology, Universidad Austral de Chile, Valdivia, Chile.,Laboratory of Immunometabolism, Faculty of Veterinary Sciences, Institute of Pharmacology and Morphophysiology, Universidad Austral de Chile, Valdivia, Chile
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26
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Palmitoylation of the K ATP channel Kir6.2 subunit promotes channel opening by regulating PIP 2 sensitivity. Proc Natl Acad Sci U S A 2020; 117:10593-10602. [PMID: 32332165 DOI: 10.1073/pnas.1918088117] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
A physiological role for long-chain acyl-CoA esters to activate ATP-sensitive K+ (KATP) channels is well established. Circulating palmitate is transported into cells and converted to palmitoyl-CoA, which is a substrate for palmitoylation. We found that palmitoyl-CoA, but not palmitic acid, activated the channel when applied acutely. We have altered the palmitoylation state by preincubating cells with micromolar concentrations of palmitic acid or by inhibiting protein thioesterases. With acyl-biotin exchange assays we found that Kir6.2, but not sulfonylurea receptor (SUR)1 or SUR2, was palmitoylated. These interventions increased the KATP channel mean patch current, increased the open time, and decreased the apparent sensitivity to ATP without affecting surface expression. Similar data were obtained in transfected cells, rat insulin-secreting INS-1 cells, and isolated cardiac myocytes. Kir6.2ΔC36, expressed without SUR, was also positively regulated by palmitoylation. Mutagenesis of Kir6.2 Cys166 prevented these effects. Clinical variants in KCNJ11 that affect Cys166 had a similar gain-of-function phenotype, but was more pronounced. Molecular modeling studies suggested that palmitoyl-C166 and selected large hydrophobic mutations make direct hydrophobic contact with Kir6.2-bound PIP2 Patch-clamp studies confirmed that palmitoylation of Kir6.2 at Cys166 enhanced the PIP2 sensitivity of the channel. Physiological relevance is suggested since palmitoylation blunted the regulation of KATP channels by α1-adrenoreceptor stimulation. The Cys166 residue is conserved in some other Kir family members (Kir6.1 and Kir3, but not Kir2), which are also subject to regulated palmitoylation, suggesting a general mechanism to control the open state of certain Kir channels.
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27
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Ulmer BM, Eschenhagen T. Human pluripotent stem cell-derived cardiomyocytes for studying energy metabolism. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2020; 1867:118471. [PMID: 30954570 PMCID: PMC7042711 DOI: 10.1016/j.bbamcr.2019.04.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 03/26/2019] [Accepted: 04/01/2019] [Indexed: 12/25/2022]
Abstract
Cardiomyocyte energy metabolism is altered in heart failure, and primary defects of metabolic pathways can cause heart failure. Studying cardiac energetics in rodent models has principal shortcomings, raising the question to which extent human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CM) can provide an alternative. As metabolic maturation of CM occurs mostly after birth during developmental hypertrophy, the immaturity of hiPSC-CM is an important limitation. Here we shortly review the physiological drivers of metabolic maturation and concentrate on methods to mature hiPSC-CM with the goal to benchmark the metabolic state of hiPSC-CM against in vivo data and to see how far known abnormalities in inherited metabolic disorders can be modeled in hiPSC-CM. The current data indicate that hiPSC-CM, despite their immature, approximately mid-fetal state of energy metabolism, faithfully recapitulate some basic metabolic disease mechanisms. Efforts to improve their metabolic maturity are underway and shall improve the validity of this model.
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Affiliation(s)
- Bärbel M Ulmer
- University Medical Center Hamburg-Eppendorf, Institute of Experimental Pharmacology and Toxicology, 20246 Hamburg, Germany; German Centre for Heart Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany.
| | - Thomas Eschenhagen
- University Medical Center Hamburg-Eppendorf, Institute of Experimental Pharmacology and Toxicology, 20246 Hamburg, Germany; German Centre for Heart Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany.
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28
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Mapa MST, Araujo M, Zhao Y, Flynn T, Sprando J, Wiesenfeld P, Sprando RL, Mossoba ME. A method to dissolve 3-MCPD mono- and di-esters in aqueous cell culture media. MethodsX 2019; 7:100774. [PMID: 32140439 PMCID: PMC7046810 DOI: 10.1016/j.mex.2019.100774] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 12/13/2019] [Indexed: 11/29/2022] Open
Abstract
Fatty acid esters of 3-monochloropropane-1,2-diol (3-MCPD) are chemical contaminants found in a wide range of edible oils that are thermally processed during industrial manufacturing of infant formula and other lipid-containing foods in the United States. Rodent studies have unequivocally demonstrated a plethora of in vivo toxicological effects including reproductive, neurological and renal dysfunction. To determine if similar effects are observed in human organ systems, in vitro studies using human cell lines are conducted to assess concordance of the data collected. One limitation to performing such in vitro research is the extremely high hydrophobicity of 3-MCPD esters; dissolving them into aqueous cell culture media is a tremendous challenge. To address this obstacle, we developed a simple protocol to circumvent the immiscibility of 3-MCPD esters and their corresponding free fatty acids into aqueous cell culture media in order to assess the effect of these esters on epithelial cells of kidney origin in vitro.
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Affiliation(s)
- Mapa S T Mapa
- Division of Applied Regulatory Toxicology (DART), Office of Applied Research and Safety Assessment (OARSA), Center for Food Safety and Applied Nutrition (CFSAN), U.S. Food and Drug Administration (US FDA), 8301 Muirkirk Rd., Laurel, MD 20708, United States
| | - Magali Araujo
- Division of Applied Regulatory Toxicology (DART), Office of Applied Research and Safety Assessment (OARSA), Center for Food Safety and Applied Nutrition (CFSAN), U.S. Food and Drug Administration (US FDA), 8301 Muirkirk Rd., Laurel, MD 20708, United States
| | - Yang Zhao
- Division of Applied Regulatory Toxicology (DART), Office of Applied Research and Safety Assessment (OARSA), Center for Food Safety and Applied Nutrition (CFSAN), U.S. Food and Drug Administration (US FDA), 8301 Muirkirk Rd., Laurel, MD 20708, United States
| | - Thomas Flynn
- Division of Applied Regulatory Toxicology (DART), Office of Applied Research and Safety Assessment (OARSA), Center for Food Safety and Applied Nutrition (CFSAN), U.S. Food and Drug Administration (US FDA), 8301 Muirkirk Rd., Laurel, MD 20708, United States
| | - Jessica Sprando
- Virginia-Maryland College of Veterinary Medicine, 205 Duck Pond Road, Blacksburg, VA 24061, United States
| | - Paddy Wiesenfeld
- Division of Applied Regulatory Toxicology (DART), Office of Applied Research and Safety Assessment (OARSA), Center for Food Safety and Applied Nutrition (CFSAN), U.S. Food and Drug Administration (US FDA), 8301 Muirkirk Rd., Laurel, MD 20708, United States
| | - Robert L Sprando
- Division of Applied Regulatory Toxicology (DART), Office of Applied Research and Safety Assessment (OARSA), Center for Food Safety and Applied Nutrition (CFSAN), U.S. Food and Drug Administration (US FDA), 8301 Muirkirk Rd., Laurel, MD 20708, United States
| | - Miriam E Mossoba
- Division of Applied Regulatory Toxicology (DART), Office of Applied Research and Safety Assessment (OARSA), Center for Food Safety and Applied Nutrition (CFSAN), U.S. Food and Drug Administration (US FDA), 8301 Muirkirk Rd., Laurel, MD 20708, United States
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29
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Kang ES, Hur J, Jo Y, Kim HJ, Han SG, Seo HG. Comparative effects of nanoemulsions loaded with duck oil and lard oil on palmitate-induced lipotoxicity. J Food Biochem 2019; 44:e13117. [PMID: 31823402 DOI: 10.1111/jfbc.13117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 10/31/2019] [Accepted: 11/24/2019] [Indexed: 12/11/2022]
Abstract
The effects of duck oil and lard oil on lipotoxicity induced by saturated long-chain fatty acids were evaluated in HepG2 cells. Lipotoxicity triggered by palmitate, a saturated fatty acid, was inhibited more by duck oil-loaded nanoemulsion (DO-NE) than by lard oil-loaded nanoemulsion (LO-NE) and control nanoemulsion (NE) in HepG2 cells. Accumulation of reactive oxygen species and lipid vacuoles in HepG2 cells induced by palmitate treatment was inhibited by DO-NE but not by LO-NE. Consistently, treatment of HepG2 cells with DO-NE, but not with NE or LO-NE, significantly reduced the expression levels of peroxisome proliferator-activated receptor-γ2 and sterol regulatory element-binding protein-1, which are key regulatory proteins in hepatic lipid accumulation. In addition, the cleavage of poly (ADP-ribose) polymerase and caspase-3 were reduced more by DO-NE than by LO-NE, indicating that DO-NE directly attenuates cellular damage induced by palmitate. Collectively, these results imply that the biological activity of duck oil against palmitate-induced cellular damage is more potent than that of lard oil. PRACTICAL APPLICATIONS: Accumulated lipids in nonadipose tissues, especially the liver, cause lipotoxicity, a pathologic feature of hepatic disorders, by inducing oxidative stress. A nanoemulsion loaded with duck oil, which is a functional food widely consumed by Korean people, inhibited lipotoxicity by suppressing lipid accumulation in HepG2 cells exposed to palmitate, which mimic nonalcoholic fatty liver disease. Thus, we propose that duck oil can be used as a functional food to improve lipid-induced hepatic disorders.
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Affiliation(s)
- Eun Sil Kang
- Department of Food Science and Biotechnology of Animal Resources, College of Sang-Huh Life Science, Konkuk University, Seoul, Korea
| | - Jinwoo Hur
- Department of Food Science and Biotechnology of Animal Resources, College of Sang-Huh Life Science, Konkuk University, Seoul, Korea
| | - Yoenji Jo
- Department of Food Science and Biotechnology of Animal Resources, College of Sang-Huh Life Science, Konkuk University, Seoul, Korea
| | - Hyo Juong Kim
- Taekyung Food and Processing R&D Center, Seoul, Korea
| | - Sung Gu Han
- Department of Food Science and Biotechnology of Animal Resources, College of Sang-Huh Life Science, Konkuk University, Seoul, Korea
| | - Han Geuk Seo
- Department of Food Science and Biotechnology of Animal Resources, College of Sang-Huh Life Science, Konkuk University, Seoul, Korea
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Lytrivi M, Castell AL, Poitout V, Cnop M. Recent Insights Into Mechanisms of β-Cell Lipo- and Glucolipotoxicity in Type 2 Diabetes. J Mol Biol 2019; 432:1514-1534. [PMID: 31628942 DOI: 10.1016/j.jmb.2019.09.016] [Citation(s) in RCA: 219] [Impact Index Per Article: 43.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Revised: 09/15/2019] [Accepted: 09/16/2019] [Indexed: 12/24/2022]
Abstract
The deleterious effects of chronically elevated free fatty acid (FFA) levels on glucose homeostasis are referred to as lipotoxicity, and the concurrent exposure to high glucose may cause synergistic glucolipotoxicity. Lipo- and glucolipotoxicity have been studied for over 25 years. Here, we review the current evidence supporting the role of pancreatic β-cell lipo- and glucolipotoxicity in type 2 diabetes (T2D), including lipid-based interventions in humans, prospective epidemiological studies, and human genetic findings. In addition to total FFA quantity, the quality of FFAs (saturation and chain length) is a key determinant of lipotoxicity. We discuss in vitro and in vivo experimental models to investigate lipo- and glucolipotoxicity in β-cells and describe experimental pitfalls. Lipo- and glucolipotoxicity adversely affect many steps of the insulin production and secretion process. The molecular mechanisms underpinning lipo- and glucolipotoxic β-cell dysfunction and death comprise endoplasmic reticulum stress, oxidative stress and mitochondrial dysfunction, impaired autophagy, and inflammation. Crosstalk between these stress pathways exists at multiple levels and may aggravate β-cell lipo- and glucolipotoxicity. Lipo- and glucolipotoxicity are therapeutic targets as several drugs impact the underlying stress responses in β-cells, potentially contributing to their glucose-lowering effects in T2D.
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Affiliation(s)
- Maria Lytrivi
- ULB Center for Diabetes Research, Medical Faculty, Université Libre de Bruxelles, Brussels, Belgium; Division of Endocrinology, Erasmus Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Anne-Laure Castell
- CRCHUM, Montréal, QC, Canada; Department of Medicine, Université de Montréal, Montréal, QC, Canada
| | - Vincent Poitout
- CRCHUM, Montréal, QC, Canada; Department of Medicine, Université de Montréal, Montréal, QC, Canada.
| | - Miriam Cnop
- ULB Center for Diabetes Research, Medical Faculty, Université Libre de Bruxelles, Brussels, Belgium; Division of Endocrinology, Erasmus Hospital, Université Libre de Bruxelles, Brussels, Belgium.
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Regué L, Minichiello L, Avruch J, Dai N. Liver-specific deletion of IGF2 mRNA binding protein-2/IMP2 reduces hepatic fatty acid oxidation and increases hepatic triglyceride accumulation. J Biol Chem 2019; 294:11944-11951. [PMID: 31209109 PMCID: PMC6682725 DOI: 10.1074/jbc.ra119.008778] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 06/05/2019] [Indexed: 12/17/2022] Open
Abstract
Insulin-like growth factor 2 mRNA-binding proteins 1-3 (IGF2BP1-3, also known as IMP1-3) contribute to the regulation of RNAs in a transcriptome-specific context. Global deletion of the mRNA-binding protein insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2 or IMP2) in mice causes resistance to obesity and fatty liver induced by a high-fat diet (HFD), whereas liver-specific IMP2 overexpression results in steatosis. To better understand the role of IMP2 in hepatic triglyceride metabolism, here we crossed mice expressing albumin-Cre with mice bearing a floxed Imp2 gene to generate hepatocyte-specific IMP2 knockout (LIMP2 KO) mice. Unexpectedly, the livers of LIMP2 KO mice fed an HFD accumulated more triglyceride. Although hepatocyte-specific IMP2 deletion did not alter lipogenic gene expression, it substantially decreased the levels of the IMP2 client mRNAs encoding carnitine palmitoyltransferase 1A (CPT1A) and peroxisome proliferator-activated receptor α (PPARα). This decrease was associated with their more rapid turnover and accompanied by significantly diminished rates of palmitate oxidation by isolated hepatocytes and liver mitochondria. HFD-fed control and LIMP2 KO mice maintained a similar glucose tolerance and insulin sensitivity up to 6 months; however, by 6 months, blood glucose and serum triglycerides in LIMP2 KO mice were modestly elevated but without evidence of liver damage. In conclusion, hepatocyte-specific IMP2 deficiency promotes modest diet-induced fatty liver by impairing fatty acid oxidation through increased degradation of the IMP2 client mRNAs PPARα and CPT1A This finding indicates that the previously observed marked protection against fatty liver conferred by global IMP2 deficiency in mice is entirely due to their reduced adiposity.
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Affiliation(s)
- Laura Regué
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114.,Diabetes Unit of the Medical Services, Massachusetts General Hospital, Boston, MA 02114.,Department of Medicine, Harvard Medical School, Boston, MA 02115
| | - Liliana Minichiello
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Joseph Avruch
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114 .,Diabetes Unit of the Medical Services, Massachusetts General Hospital, Boston, MA 02114.,Department of Medicine, Harvard Medical School, Boston, MA 02115
| | - Ning Dai
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114 .,Diabetes Unit of the Medical Services, Massachusetts General Hospital, Boston, MA 02114.,Department of Medicine, Harvard Medical School, Boston, MA 02115
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Tardo-Dino PE, Touron J, Baugé S, Bourdon S, Koulmann N, Malgoyre A. The effect of a physiological increase in temperature on mitochondrial fatty acid oxidation in rat myofibers. J Appl Physiol (1985) 2019; 127:312-319. [PMID: 31161881 DOI: 10.1152/japplphysiol.00652.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
We investigated the effect of temperature increase on mitochondrial fatty acid (FA) and carbohydrate oxidation in the slow-oxidative skeletal muscles (soleus) of rats. We measured mitochondrial respiration at 35°C and 40°C with the physiological substrates pyruvate + 4 mM malate (Pyr) and palmitoyl-CoA (PCoA) + 0.5 mM malate + 2 mM carnitine in permeabilized myofibers under nonphosphorylating (V˙0) or phosphorylating (V˙max) conditions. Mitochondrial efficiency was calculated by the respiratory control ratio (RCR = V˙max/V˙0). We used guanosine triphosphate (GTP), an inhibitor of uncoupling protein (UCP), to study the mechanisms responsible for alterations of mitochondrial efficiency. We measured hydrogen peroxide (H2O2) production under nonphosphorylating and phosphorylating conditions at both temperatures and substrates. We studied citrate synthase (CS) and 3-hydroxyl acyl coenzyme A dehydrogenase (3-HAD) activities at both temperatures. Elevating the temperature from 35°C to 40°C increased PCoA-V˙0 and decreased PCoA-RCR, corresponding to the uncoupling of oxidative phosphorylation (OXPHOS). GTP blocked the heat-induced increase of PCoA-V˙0. Rising temperature moved toward a Pyr-V˙0 increase, without significance. Heat did not alter H2O2 production, resulting from either PCoA or Pyr oxidation. Heat induced an increase in 3-HAD but not in CS activities. In conclusion, heat induced OXPHOS uncoupling for PCoA oxidation, which was at least partially mediated by UCP and independent of oxidative stress. The classically described heat-induced glucose shift may actually be mostly due to a less efficient FA oxidation. These findings raise questions concerning the consequences of heat-induced alterations in mitochondrial efficiency of FA metabolism on thermoregulation.NEW & NOTEWORTHY Ex vivo exposure of skeletal myofibers to heat uncouples substrate oxidation from ADP phosphorylation, decreasing the efficiency of mitochondria to produce ATP. This heat effect alters fatty acids (FAs) more than carbohydrate oxidation. Alteration of FA oxidation involves uncoupling proteins without inducing oxidative stress. This alteration in lipid metabolism may underlie the preferential use of carbohydrates in the heat and could decrease aerobic endurance.
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Affiliation(s)
- Pierre-Emmanuel Tardo-Dino
- Unité de Physiologie de l'Exercice et des Activités en Conditions Extrêmes, Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Brétigny sur Orge, France.,Ecole du Val-de-Grâce, Paris, France.,EDISS 205, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Julianne Touron
- Unité de Physiologie de l'Exercice et des Activités en Conditions Extrêmes, Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Brétigny sur Orge, France
| | - Stéphane Baugé
- Unité de Physiologie de l'Exercice et des Activités en Conditions Extrêmes, Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Brétigny sur Orge, France
| | - Stéphanie Bourdon
- Unité de Physiologie de l'Exercice et des Activités en Conditions Extrêmes, Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Brétigny sur Orge, France
| | - Nathalie Koulmann
- Unité de Physiologie de l'Exercice et des Activités en Conditions Extrêmes, Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Brétigny sur Orge, France.,Ecole du Val-de-Grâce, Paris, France.,EDISS 205, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Alexandra Malgoyre
- Unité de Physiologie de l'Exercice et des Activités en Conditions Extrêmes, Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Brétigny sur Orge, France
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Šimek M, Hermannová M, Šmejkalová D, Foglová T, Souček K, Binó L, Velebný V. LC–MS/MS study of in vivo fate of hyaluronan polymeric micelles carrying doxorubicin. Carbohydr Polym 2019; 209:181-189. [DOI: 10.1016/j.carbpol.2018.12.104] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 12/13/2018] [Accepted: 12/27/2018] [Indexed: 11/28/2022]
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IMP2 Increases Mouse Skeletal Muscle Mass and Voluntary Activity by Enhancing Autocrine Insulin-Like Growth Factor 2 Production and Optimizing Muscle Metabolism. Mol Cell Biol 2019; 39:MCB.00528-18. [PMID: 30692269 DOI: 10.1128/mcb.00528-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 01/19/2019] [Indexed: 12/27/2022] Open
Abstract
Insulin-like growth factor 2 (IGF2) mRNA binding protein 2 (IMP2) was selectively deleted from adult mouse muscle; two phenotypes were observed: decreased accrual of skeletal muscle mass after weaning and reduced wheel-running activity but normal forced treadmill performance. Reduced wheel running occurs when mice are fed a high-fat diet but is normalized when mice consume standard chow. The two phenotypes are due to altered output from different IMP2 client mRNAs. The reduced fiber size of IMP2-deficient muscle is attributable, in part, to diminished autocrine Igf2 production; basal tyrosine phosphorylation of the insulin and IGF1 receptors is diminished, and Akt1 activation is selectively reduced. Gsk3α is disinhibited, and S536-phosphorylated ε subunit of eukaryotic initiation factor 2B [eIF2Bε(S536)] is hyperphosphorylated. Protein synthesis is reduced despite unaltered mTOR complex 1 activity. The diet-dependent reduction in voluntary exercise is likely due to altered muscle metabolism, as contractile function is normal. IMP2-deficient muscle exhibits reduced fatty acid oxidation, due to a reduced abundance of mRNA of peroxisome proliferator-activated receptor α (PPARα), an IMP2 client, and PPARα protein. IMP2-deficient muscle fibers treated with a mitochondrial uncoupler to increase electron flux, as occurs with exercise, exhibit reduced oxygen consumption from fatty acids, with higher oxygen consumption from glucose. The greater dependence on muscle glucose metabolism during increased oxygen demand may promote central fatigue and thereby diminish voluntary activity.
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35
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Oxylipins mediate cell-to-cell communication in Pseudomonas aeruginosa. Commun Biol 2019; 2:66. [PMID: 30793044 PMCID: PMC6377657 DOI: 10.1038/s42003-019-0310-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 01/15/2019] [Indexed: 12/20/2022] Open
Abstract
Oxygenated unsaturated fatty acids, known as oxylipins, are signaling molecules commonly used for cell-to-cell communication in eukaryotes. However, a role for oxylipins in mediating communication in prokaryotes has not previously been described. Bacteria mainly communicate via quorum sensing, which involves the production and detection of diverse small molecules termed autoinducers. Here we show that oleic acid-derived oxylipins produced by Pseudomonas aeruginosa function as autoinducers of a novel quorum sensing system. We found that this system controls the cell density-dependent expression of a gene subset independently of the quorum sensing systems thus far described in this bacterium. We identified a LysR-type transcriptional regulator as the primary receptor of the oxylipin signal. The discovery of this oxylipin-dependent quorum sensing system reveals that prokaryote-derived oxylipins also mediate cell-to-cell communication in bacteria. Eriel Martínez et al. report that the bacterial pathogen Pseudomonas aeruginosa can convert oleic acids into oxylipins for use in cell-cell communication. This quorum sensing system is regulated by the bacterial protein called oxylipin-dependent diol synthase regulator OdsR.
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36
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Dalla Valle A, Vertongen P, Spruyt D, Lechanteur J, Suain V, Gaspard N, Brion JP, Gangji V, Rasschaert J. Induction of Stearoyl-CoA 9-Desaturase 1 Protects Human Mesenchymal Stromal Cells Against Palmitic Acid-Induced Lipotoxicity and Inflammation. Front Endocrinol (Lausanne) 2019; 10:726. [PMID: 31708874 PMCID: PMC6822410 DOI: 10.3389/fendo.2019.00726] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 10/09/2019] [Indexed: 12/11/2022] Open
Abstract
In bone diseases such as osteonecrosis and osteoporosis, a shift toward a preferential differentiation of mesenchymal stromal cells (MSC) into adipocytes at the expense of the osteoblastic lineage is described, leading to excessive accumulation of adipocytes in the bone marrow of the patients. The influence of cytokines and adipokines secreted by adipocytes on skeletal health is already well-documented but the impact of free fatty acids release on bone cell biology and viability is an emerging concept. We have previously demonstrated that the saturated fatty acid (SFA) palmitate (Palm) is cytotoxic for human MSC (hMSC) and osteoblasts whereas oleate (Ole), a monounsaturated fatty acid (MUFA), has no toxic effect. Moreover, Ole protects cells against lipotoxicity. Our observations led us to propose that the toxicity of the SFA is not correlated to its intracellular accumulation but could rather be related to the intracellular SFA/MUFA ratio, which finally determines the toxic effect of SFA. Therefore, in the present study, we have investigated the potential protective role of the enzyme stearoyl-CoA 9-desaturase 1 (SCD1) against the deleterious effects of Palm. SCD1 is an enzyme responsible for desaturation of SFA to MUFA; its activation could therefore lead to modifications of the intracellular SFA/MUFA ratio. In the present study, we showed that hMSC express SCD1 and liver X receptors (LXRs), transcription factors regulating SCD1 expression. Human MSC treatment with a LXRs agonist triggered SCD1 expression and drastically reduced Palm-induced cell mortality, caspases 3/7 activation, endoplasmic reticulum stress and inflammation. We also observed that, in the presence of Palm, the LXRs agonist provoked lipid droplets formation, augmented the total cellular neutral lipid content but decreased the SFA/MUFA ratio when compared to Palm treatment alone. Addition of an inhibitor of SCD1 activity abrogated the positive effects of the LXRs agonist, suggesting that SCD1 could play a key role in protecting hMSC against lipotoxicity.
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Affiliation(s)
- Antoine Dalla Valle
- Laboratory of Bone and Metabolic Biochemistry, Faculty of Medicine, Université libre de Bruxelles, Brussels, Belgium
| | - Pascale Vertongen
- Laboratory of Bone and Metabolic Biochemistry, Faculty of Medicine, Université libre de Bruxelles, Brussels, Belgium
| | - Delphine Spruyt
- Laboratory of Bone and Metabolic Biochemistry, Faculty of Medicine, Université libre de Bruxelles, Brussels, Belgium
| | - Jessica Lechanteur
- Laboratory of Bone and Metabolic Biochemistry, Faculty of Medicine, Université libre de Bruxelles, Brussels, Belgium
| | - Valérie Suain
- Laboratory of Histology, Neuroanatomy and Neuropathology, Faculty of Medicine, ULB Neuroscience Institute (UNI), Université libre de Bruxelles, Brussels, Belgium
| | - Nathalie Gaspard
- Laboratory of Bone and Metabolic Biochemistry, Faculty of Medicine, Université libre de Bruxelles, Brussels, Belgium
| | - Jean-Pierre Brion
- Laboratory of Histology, Neuroanatomy and Neuropathology, Faculty of Medicine, ULB Neuroscience Institute (UNI), Université libre de Bruxelles, Brussels, Belgium
| | - Valérie Gangji
- Laboratory of Bone and Metabolic Biochemistry, Faculty of Medicine, Université libre de Bruxelles, Brussels, Belgium
- Department of Rheumatology and Physical Medicine, Erasme Hospital, Université libre de Bruxelles, Brussels, Belgium
| | - Joanne Rasschaert
- Laboratory of Bone and Metabolic Biochemistry, Faculty of Medicine, Université libre de Bruxelles, Brussels, Belgium
- *Correspondence: Joanne Rasschaert
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Early Exposure to a High-Fat Diet Impacts on Hippocampal Plasticity: Implication of Microglia-Derived Exosome-like Extracellular Vesicles. Mol Neurobiol 2018; 56:5075-5094. [PMID: 30474797 DOI: 10.1007/s12035-018-1435-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 11/15/2018] [Indexed: 12/18/2022]
Abstract
Adolescence is a transitional period from childhood to adulthood characterized by puberty and brain maturation involving behavioral changes and environmental vulnerability. Diet is one of the factors affecting brain health, potentially leading to long-lasting effects. Hence, we studied the impact of early exposure (P21-60) to a high-fat diet (HFD) on mouse hippocampus, analyzing inflammation, adult neurogenesis, dendritic spine plasticity, and spatial memory. Glycemia and seric pro-inflammatory IL1β were higher in HFD mice without differences on body weight. In the HFD hippocampus, neuroinflammation was evidenced by Iba1+ cells reactivity together with a higher expression of TNFα and IL1β while the neurogenic capability in the dentate gyrus was strongly reduced. We found a predominance of immature Dil-labeled dendritic spines from CA1 neurons along with diminished levels of the scaffold protein Shank2, suggesting a defective connectivity. Moreover, the HFD group exhibited spatial memory alterations. To elucidate whether microglia could be mediating HFD-associated neuronal changes, the lipotoxic context was emulated by incubating primary microglia with palmitate, a saturated fatty acid present in HFD. Palmitate induced a pro-inflammatory profile as shown by secreted cytokine levels. The isolated exosome fraction from palmitate-stimulated microglia induced an immature dendritic spine phenotype in primary GFP+ hippocampal neurons, in line with the in vivo findings. These results provide novel data concerning microglia to neuron communication and highlight that fat excess during a short and early period of life could negatively impact on cognition and synaptic plasticity in a neuroinflammatory context, where microglia-derived exosomes could be implicated. Graphical Abstract ᅟ.
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Lee EJ, Hwang JS, Kang ES, Lee SB, Hur J, Lee WJ, Choi MJ, Kim JT, Seo HG. Nanoemulsions improve the efficacy of turmeric in palmitate- and high fat diet-induced cellular and animal models. Biomed Pharmacother 2018; 110:181-189. [PMID: 30469082 DOI: 10.1016/j.biopha.2018.11.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 10/29/2018] [Accepted: 11/02/2018] [Indexed: 02/09/2023] Open
Abstract
Turmeric is a well-known functional food exhibiting multiple biological activities in health and disease. However, low aqueous solubility and poor bioavailability limit its therapeutic potential. Herein, we investigated the utility of nanoemulsions as a carrier to improve the efficacy of turmeric. Compared with turmeric extract (TE), 5% TE-loaded nanoemulsion (TE-NE), which contains 20-fold lower curcumin content than TE, achieved similar inhibition of palmitate-induced lipotoxicity in HepG2 cells. Exposure of HepG2 cells to 5% TE-NE also suppressed the palmitate-induced accumulation of lipid vacuoles and reactive oxygen species comparably with TE, and was accompanied by decreased levels of sterol regulatory element-binding protein (SREBP)-1, peroxisome proliferator-activated receptor-γ2 (PPAR-γ2), cleaved caspase-3, and poly (ADP-ribose) polymerase (PARP). Consistent with these effects in HepG2 cells, oral administration of 5% TE-NE to mice fed a high fat diet (HFD) markedly suppressed lipid accumulation in liver, leading to a significant reduction in body weight and adipose tissue weight, equivalent to the effects observed with TE. Compared with TE, 5% TE-NE also equivalently inhibited the levels of SREBP-1, PPAR-γ2, cleaved caspase-3, and PARP in the liver of mice fed a HFD. Furthermore, TE and 5% TE-NE significantly improved serum lipid profiles in a similar manner. These observations indicate that nanoemulsions can improve the efficacy of turmeric, thereby eliciting more potent biological efficacy against palmitate- and high fat diet (HFD)-induced cellular damage.
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Affiliation(s)
- Eun Ji Lee
- Department of Food Science and Biotechnology of Animal Resources, College of Sang-Huh Life Science, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea
| | - Jung Seok Hwang
- Department of Food Science and Biotechnology of Animal Resources, College of Sang-Huh Life Science, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea
| | - Eun Sil Kang
- Department of Food Science and Biotechnology of Animal Resources, College of Sang-Huh Life Science, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea
| | - Su Bi Lee
- Department of Food Science and Technology, Keimyung University, Daegu, Republic of Korea
| | - Jinwoo Hur
- Department of Food Science and Biotechnology of Animal Resources, College of Sang-Huh Life Science, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea
| | - Won Jin Lee
- Department of Food Science and Biotechnology of Animal Resources, College of Sang-Huh Life Science, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea
| | - Mi-Jung Choi
- Department of Food Science and Biotechnology of Animal Resources, College of Sang-Huh Life Science, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea
| | - Jun Tae Kim
- Department of Food Science and Technology, Keimyung University, Daegu, Republic of Korea
| | - Han Geuk Seo
- Department of Food Science and Biotechnology of Animal Resources, College of Sang-Huh Life Science, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea.
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Ono-Moore KD, Blackburn ML, Adams SH. Is palmitate truly proinflammatory? Experimental confounders and context-specificity. Am J Physiol Endocrinol Metab 2018; 315:E780-E794. [PMID: 30016150 DOI: 10.1152/ajpendo.00187.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Based primarily on cell culture results, saturated fatty acids (SFAs) are proposed to promote inflammation and contribute to metabolic dysfunction through Toll-like receptor activation. Studies are often complicated by a requirement for carriers (e.g., BSA) or solvents (e.g., ethanol) to increase SFA solubility. To ascertain whether these factors influence interpretations of SFA-associated inflammation activity, we measured responses of RAW264.7 monocyte/macrophages and C2C12 myotubes to various BSA, ethanol, and cyclodextrin (alternative FA carrier) conditions. Fatty acid-free, low-endotoxin BSA preparations (0.33% to 2% wt/vol) activated whereas 0.5-1.0% ethanol inhibited RAW264.7 TNFα release. Ethanol modestly increased IL-6 secretion in C2C12 myotubes. Cyclodextrins (0.3-6.0 mM) were tested as alternative carriers of palmitate, but their usefulness was limited due to toxicity and solubility issues. Using a lower-inflammation BSA source and no ethanol, ∼24-h sodium palmitate treatment (≤600 µM) failed to trigger RAW264.7 TNFα release and, in fact, significantly dampened BSA-induced inflammation by >50%. In C2C12 myotubes, only high palmitate concentrations (500-600 µM) elicited IL-6 secretion (>2.5-fold increase). Acute palmitate (200 or 500 µM) treatment did not activate MAP kinase pathways above that of fresh BSA-containing media alone in either cell type. These results highlight the importance of experimental conditions in studies exploring SFA inflammation effects. The limited (or even anti-inflammatory) effects of palmitate that we observed indicate that immunomodulatory effects of SFAs are context-specific. Thus, caution is needed when interpreting the literature related to putative proinflammatory effects of SFA.
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Affiliation(s)
| | - Michael L Blackburn
- Arkansas Children's Nutrition Center , Little Rock, Arkansas
- Department of Pediatrics, University of Arkansas for Medical Sciences , Little Rock, Arkansas
| | - Sean H Adams
- Arkansas Children's Nutrition Center , Little Rock, Arkansas
- Department of Pediatrics, University of Arkansas for Medical Sciences , Little Rock, Arkansas
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Giacco A, Delli Paoli G, Senese R, Cioffi F, Silvestri E, Moreno M, Ruoppolo M, Caterino M, Costanzo M, Lombardi A, Goglia F, Lanni A, de Lange P. The saturation degree of fatty acids and their derived acylcarnitines determines the direct effect of metabolically active thyroid hormones on insulin sensitivity in skeletal muscle cells. FASEB J 2018; 33:1811-1823. [PMID: 30204501 DOI: 10.1096/fj.201800724r] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Using differentiated rat L6 cells, we studied the direct effect of 3,5,3'-triiodo-l-thyronine (T3) and 3,5-diiodo-l-thyronine (T2) on the response to insulin in presence of fatty acids with a varying degree of saturation. We found that T3 and T2 both invert the response to insulin by modulating Akt Ser473 phosphorylation in the presence of palmitate and oleate. Both hormones prevented palmitate-induced insulin resistance, whereas increased insulin sensitivity in the presence of oleate was reduced, with normalization to (or, in the case of T3, even below) control levels. Both hormones effectively reduced intracellular acylcarnitine concentrations. Interestingly, insulin sensitization was lowered by incubation of the myotubes with relevant concentrations of palmitoylcarnitines (C16) and increased by oleylcarnitines and linoleylcarnitines (C18:1 and C18:2, respectively). The efficiency of mitochondrial respiration decreased in the order palmitate-oleate-linoleate; in the presence of palmitate, only T3 increased ATP synthesis-independent cellular respiration and mitochondrial respiratory complex activities. Both hormones modulated gene expression and enzyme activities related to insulin sensitivity, glucose metabolism, and lipid handling. Although T2 and T3 differentially regulated the expression of relevant genes involved in glucose metabolism, they equally stimulated related metabolic activities. T2 and T3 differentially modulated mitochondrial fatty acid uptake and oxidation in the presence of each fatty acid. The results show that T2 and T3 both invert the fatty acid-induced response to insulin but through different mechanisms, and that the outcome depends on the degree of saturation of the fatty acids and their derived acylcarnitines.-Giacco, A., delli Paoli, G., Senese, R., Cioffi, F., Silvestri, E., Moreno, M., Ruoppolo, M., Caterino, M., Costanzo, M., Lombardi, A., Goglia, F., Lanni, A., de Lange, P. The saturation degree of fatty acids and their derived acylcarnitines determines the direct effect of metabolically active thyroid hormones on insulin sensitivity in skeletal muscle cells.
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Affiliation(s)
- Antonia Giacco
- Dipartimento di Scienze e Tecnologie, Università degli Studi del Sannio, Benevento, Italy
| | - Giuseppe Delli Paoli
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli Studi della Campania Luigi Vanvitelli, Caserta, Italy
| | - Rosalba Senese
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli Studi della Campania Luigi Vanvitelli, Caserta, Italy
| | - Federica Cioffi
- Dipartimento di Scienze e Tecnologie, Università degli Studi del Sannio, Benevento, Italy
| | - Elena Silvestri
- Dipartimento di Scienze e Tecnologie, Università degli Studi del Sannio, Benevento, Italy
| | - Maria Moreno
- Dipartimento di Scienze e Tecnologie, Università degli Studi del Sannio, Benevento, Italy
| | - Margherita Ruoppolo
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, Naples, Italy.,Ceinge-Biotecnologie Avanzate, Naples, Italy.,Divulgazione Scientifica Multidisciplinare per la Sostenibilità Ricerca, Formazione, Cultura (DiSciMuS RCF), Naples, Italy
| | - Marianna Caterino
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, Naples, Italy.,Ceinge-Biotecnologie Avanzate, Naples, Italy.,Divulgazione Scientifica Multidisciplinare per la Sostenibilità Ricerca, Formazione, Cultura (DiSciMuS RCF), Naples, Italy
| | - Michele Costanzo
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, Naples, Italy.,Ceinge-Biotecnologie Avanzate, Naples, Italy.,Divulgazione Scientifica Multidisciplinare per la Sostenibilità Ricerca, Formazione, Cultura (DiSciMuS RCF), Naples, Italy
| | - Assunta Lombardi
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Naples, Italy
| | - Fernando Goglia
- Dipartimento di Scienze e Tecnologie, Università degli Studi del Sannio, Benevento, Italy
| | - Antonia Lanni
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli Studi della Campania Luigi Vanvitelli, Caserta, Italy
| | - Pieter de Lange
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli Studi della Campania Luigi Vanvitelli, Caserta, Italy
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41
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Hosios AM, Li Z, Lien EC, Heiden MVG. Preparation of Lipid-Stripped Serum for the Study of Lipid Metabolism in Cell Culture. Bio Protoc 2018; 8:e2876. [PMID: 34285990 DOI: 10.21769/bioprotoc.2876] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 05/15/2018] [Accepted: 05/23/2018] [Indexed: 11/02/2022] Open
Abstract
Studying lipid metabolism in cultured cells is complicated by the fact that cells are typically cultured in the presence of animal serum, which contains a wide, variable, and undefined variety of lipid species. Lipid metabolism can impact cell physiology, signaling, and proliferation, and the ability to culture cells in the absence of exogenous lipids can reveal the importance of lipid biosynthesis pathways and facilitate the generation of media with defined lipid species. We have adapted a protocol to remove lipids from serum without eliminating its ability to support the proliferation of cells in culture. This method requires di-isopropyl ether and butanol and can be used to generate small batches of lipid-stripped serum in four days. The resulting serum supports proliferation of many cell lines in culture and can be used to compare the metabolism of cells in lipid replete and depleted conditions.
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Affiliation(s)
- Aaron M Hosios
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Zhaoqi Li
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Evan C Lien
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Matthew Vander G Heiden
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.,Dana-Farber Cancer Institute, Boston, MA, USA
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42
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Mann-Krzisnik D, Verhaegen F, Enger SA. The influence of tissue composition uncertainty on dose distributions in brachytherapy. Radiother Oncol 2018; 126:394-410. [PMID: 29428259 DOI: 10.1016/j.radonc.2018.01.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 12/31/2017] [Accepted: 01/05/2018] [Indexed: 11/26/2022]
Abstract
BACKGROUND AND PURPOSE Model-based dose calculation algorithms (MBDCAs) have evolved from serving as a research tool into clinical practice in brachytherapy. This study investigates primary sources of tissue elemental compositions used as input to MBDCAs and the impact of their variability on MBDCA-based dosimetry. MATERIALS AND METHODS Relevant studies were retrieved through PubMed. Minimum dose delivered to 90% of the target (D90), minimum dose delivered to the hottest specified volume for organs at risk (OAR) and mass energy-absorption coefficients (μen/ρ) generated by using EGSnrc "g" user-code were compared to assess the impact of compositional variability. RESULTS Elemental composition for hydrogen, carbon, oxygen and nitrogen are derived from the gross contents of fats, proteins and carbohydrates for any given tissue, the compositions of which are taken from literature dating back to 1940-1950. Heavier elements are derived from studies performed in the 1950-1960. Variability in elemental composition impacts greatly D90 for target tissues and doses to OAR for brachytherapy with low energy sources and less for 192Ir-based brachytherapy. Discrepancies in μen/ρ are also indicative of dose differences. CONCLUSIONS Updated elemental compositions are needed to optimize MBDCA-based dosimetry. Until then, tissue compositions based on gross simplifications in early studies will dominate the uncertainties in tissue heterogeneity.
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Affiliation(s)
| | - Frank Verhaegen
- Department of Radiation Oncology (MAASTRO), GROW - School for Oncology and Developmental Biology, Maastricht University Medical Centre, The Netherlands
| | - Shirin A Enger
- Medical Physics Unit, McGill University, Montreal, Canada; Department of Oncology, McGill University, Montreal, Canada; Research Institute of the McGill University Health Centre, Montreal, Canada
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43
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Raman P, Madhavpeddi L, Gonzales RJ. Palmitate induces glycosylation of cyclooxygenase-2 in primary human vascular smooth muscle cells. Am J Physiol Cell Physiol 2018; 314:C545-C553. [PMID: 29384693 DOI: 10.1152/ajpcell.00254.2017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Vascular basal cyclooxygenase-2 (COX-2) expression and activity can be induced by endotoxin, hypoxia, or ischemia. During vascular pathologies such as atherosclerosis, increases in COX-2 activity result in prostanoid production, a contributor to the development and progression of vascular inflammation leading to unstable atherosclerotic plaques and increased risk for thrombotic events. Recent studies demonstrate that select free fatty acids, such as palmitate, can act as proinflammatory mediators. However, the effect of palmitate on COX-2 expression and activity, and its impact on the development and progression of vascular inflammation, are not well elucidated. We investigated the effect of palmitate on COX-2 expression and function in human vascular smooth muscle cells. Cells were treated with palmitate, COX-2 protein levels were assessed using Western analysis, and activity was assessed via ELISA. We observed that palmitate dose-dependently increased COX-2 levels and specifically enhanced band intensity of the COX-2 74 kDa band (slowest migrating band). This response was attenuated by N-linked glycosylation inhibition, suggesting that palmitate impacts expression of the fully activated glycoform of COX-2. Palmitate-induced increases in COX-2 levels correlated with an increase in prostaglandin E2 production that was also attenuated by a glycosylation inhibitor. Additionally, palmitate altered cell morphology and increased cell density which were reversed by selective COX-2 inhibition. Thus, we conclude that palmitate acts on COX-2 by two separate mechanisms of action in human vascular smooth muscle. It elicits dose-dependent increases in COX-2 protein expression and modulates regulation of COX-2 activity via modification of posttranslational glycosylation.
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Affiliation(s)
- Puneet Raman
- Department of Basic Medical Sciences, University of Arizona College of Medicine - Phoenix , Phoenix, Arizona
| | - Lakshmi Madhavpeddi
- Department of Basic Medical Sciences, University of Arizona College of Medicine - Phoenix , Phoenix, Arizona
| | - Rayna J Gonzales
- Department of Basic Medical Sciences, University of Arizona College of Medicine - Phoenix , Phoenix, Arizona
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44
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Alsabeeh N, Chausse B, Kakimoto PA, Kowaltowski AJ, Shirihai O. Cell culture models of fatty acid overload: Problems and solutions. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1863:143-151. [PMID: 29155055 DOI: 10.1016/j.bbalip.2017.11.006] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 11/09/2017] [Accepted: 11/14/2017] [Indexed: 12/17/2022]
Abstract
High plasma levels of fatty acids occur in a variety of metabolic diseases. Cellular effects of fatty acid overload resulting in negative cellular responses (lipotoxicity) are often studied in vitro, in an attempt to understand mechanisms involved in these diseases. Fatty acids are poorly soluble, and thus usually studied when complexed to albumins such as bovine serum albumin (BSA). The conjugation of fatty acids to albumin requires care pertaining to preparation of the solutions, effective free fatty acid concentrations, use of different fatty acid species, types of BSA, appropriate controls and ensuring cellular fatty acid uptake. This review discusses lipotoxicity models, the potential problems encountered when using these cellular models, as well as practical solutions for difficulties encountered.
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Affiliation(s)
- Nour Alsabeeh
- Department of Medicine, Division of Endocrinology, Diabetes and Hypertension, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA; Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118, USA; Department of Physiology, Faculty of Medicine, Kuwait University, Kuwait
| | - Bruno Chausse
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP 05508-000, Brazil
| | - Pamela A Kakimoto
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP 05508-000, Brazil
| | - Alicia J Kowaltowski
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP 05508-000, Brazil.
| | - Orian Shirihai
- Department of Medicine, Division of Endocrinology, Diabetes and Hypertension, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA
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45
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Palmitate-induced lipotoxicity alters acetylation of multiple proteins in clonal β cells and human pancreatic islets. Sci Rep 2017; 7:13445. [PMID: 29044173 PMCID: PMC5647430 DOI: 10.1038/s41598-017-13908-w] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 09/14/2017] [Indexed: 02/02/2023] Open
Abstract
Type 2 diabetes is characterized by progressive β cell dysfunction, with lipotoxicity playing a possible pathogenetic role. Palmitate is often used to examine the direct effects of lipotoxicity and it may cause mitochondrial alterations by activating protein acetylation. However, it is unknown whether palmitate influences protein acetylation in β cells. We investigated lysine acetylation in mitochondrial proteins from INS-1E β cells (INS-1E) and in proteins from human pancreatic islets (HPI) after 24 h palmitate exposure. First, we confirmed that palmitate damages β cells and demonstrated that chemical inhibition of deacetylation also impairs INS-1E function and survival. Then, by 2-D gel electrophoresis, Western Blot and Liquid Chromatography-Mass Spectrometry we evaluated the effects of palmitate on protein acetylation. In mitochondrial preparations from palmitate-treated INS-1E, 32 acetylated spots were detected, with 13 proteins resulting over-acetylated. In HPI, 136 acetylated proteins were found, of which 11 were over-acetylated upon culture with palmitate. Interestingly, three proteins, glutamate dehydrogenase, mitochondrial superoxide dismutase, and SREBP-1, were over-acetylated in both INS-1E and HPI. Therefore, prolonged exposure to palmitate induces changes in β cell protein lysine acetylation and this modification could play a role in causing β cell damage. Dysregulated acetylation may be a target to counteract palmitate-induced β cell lipotoxicity.
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46
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Cunha DA, Cito M, Grieco FA, Cosentino C, Danilova T, Ladrière L, Lindahl M, Domanskyi A, Bugliani M, Marchetti P, Eizirik DL, Cnop M. Pancreatic β-cell protection from inflammatory stress by the endoplasmic reticulum proteins thrombospondin 1 and mesencephalic astrocyte-derived neutrotrophic factor (MANF). J Biol Chem 2017; 292:14977-14988. [PMID: 28698383 DOI: 10.1074/jbc.m116.769877] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Revised: 06/26/2017] [Indexed: 12/16/2022] Open
Abstract
Cytokine-induced endoplasmic reticulum (ER) stress is one of the molecular mechanisms underlying pancreatic β-cell demise in type 1 diabetes. Thrombospondin 1 (THBS1) was recently shown to promote β-cell survival during lipotoxic stress. Here we show that ER-localized THBS1 is cytoprotective to rat, mouse, and human β-cells exposed to cytokines or thapsigargin-induced ER stress. THBS1 confers cytoprotection by maintaining expression of mesencephalic astrocyte-derived neutrotrophic factor (MANF) in β-cells and thereby prevents the BH3-only protein BIM (BCL2-interacting mediator of cell death)-dependent triggering of the mitochondrial pathway of apoptosis. Prolonged exposure of β-cells to cytokines or thapsigargin leads to THBS1 and MANF degradation and loss of this prosurvival mechanism. Approaches that sustain intracellular THBS1 and MANF expression in β-cells should be explored as a cytoprotective strategy in type 1 diabetes.
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Affiliation(s)
- Daniel A Cunha
- From the Université Libre de Bruxelles Center for Diabetes Research, Faculty of Medicine, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Monia Cito
- From the Université Libre de Bruxelles Center for Diabetes Research, Faculty of Medicine, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Fabio Arturo Grieco
- From the Université Libre de Bruxelles Center for Diabetes Research, Faculty of Medicine, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Cristina Cosentino
- From the Université Libre de Bruxelles Center for Diabetes Research, Faculty of Medicine, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Tatiana Danilova
- the Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Laurence Ladrière
- From the Université Libre de Bruxelles Center for Diabetes Research, Faculty of Medicine, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Maria Lindahl
- the Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Andrii Domanskyi
- the Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Marco Bugliani
- the Department of Endocrinology and Metabolism, University of Pisa, 56100 Pisa, Italy, and
| | - Piero Marchetti
- the Department of Endocrinology and Metabolism, University of Pisa, 56100 Pisa, Italy, and
| | - Décio L Eizirik
- From the Université Libre de Bruxelles Center for Diabetes Research, Faculty of Medicine, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Miriam Cnop
- From the Université Libre de Bruxelles Center for Diabetes Research, Faculty of Medicine, Université Libre de Bruxelles, 1070 Brussels, Belgium, .,the Division of Endocrinology, Erasmus Hospital, Université Libre de Bruxelles, 1070 Brussels, Belgium
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47
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Abdulkarim B, Hernangomez M, Igoillo-Esteve M, Cunha DA, Marselli L, Marchetti P, Ladriere L, Cnop M. Guanabenz Sensitizes Pancreatic β Cells to Lipotoxic Endoplasmic Reticulum Stress and Apoptosis. Endocrinology 2017; 158:1659-1670. [PMID: 28323924 DOI: 10.1210/en.2016-1773] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 02/24/2017] [Indexed: 12/18/2022]
Abstract
Deficient as well as excessive/prolonged endoplasmic reticulum (ER) stress signaling can lead to pancreatic β cell failure and the development of diabetes. Saturated free fatty acids (FFAs) such as palmitate induce lipotoxic ER stress in pancreatic β cells. One of the main ER stress response pathways is under the control of the protein kinase R-like endoplasmic reticulum kinase (PERK), leading to phosphorylation of the eukaryotic translation initiation factor 2 (eIF2α). The antihypertensive drug guanabenz has been shown to inhibit eIF2α dephosphorylation and protect cells from ER stress. Here we examined whether guanabenz protects pancreatic β cells from lipotoxicity. Guanabenz induced β cell dysfunction in vitro and in vivo in rodents and led to impaired glucose tolerance. The drug significantly potentiated FFA-induced cell death in clonal rat β cells and in rat and human islets. Guanabenz enhanced FFA-induced eIF2α phosphorylation and expression of the downstream proapoptotic gene C/EBP homologous protein (CHOP), which mediated the sensitization to lipotoxicity. Thus, guanabenz does not protect β cells from ER stress; instead, it potentiates lipotoxic ER stress through PERK/eIF2α/CHOP signaling. These data demonstrate the crucial importance of the tight regulation of eIF2α phosphorylation for the normal function and survival of pancreatic β cells.
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Affiliation(s)
- Baroj Abdulkarim
- ULB Center for Diabetes Research, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Miriam Hernangomez
- ULB Center for Diabetes Research, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | | | - Daniel A Cunha
- ULB Center for Diabetes Research, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Lorella Marselli
- Department of Endocrinology and Metabolism, University of Pisa, 56126 Pisa, Italy
| | - Piero Marchetti
- Department of Endocrinology and Metabolism, University of Pisa, 56126 Pisa, Italy
| | - Laurence Ladriere
- ULB Center for Diabetes Research, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Miriam Cnop
- ULB Center for Diabetes Research, Université Libre de Bruxelles, 1070 Brussels, Belgium
- Division of Endocrinology, Erasmus Hospital, 1070 Brussels, Belgium
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48
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Lee SH, Cunha D, Piermarocchi C, Paternostro G, Pinkerton A, Ladriere L, Marchetti P, Eizirik DL, Cnop M, Levine F. High-throughput screening and bioinformatic analysis to ascertain compounds that prevent saturated fatty acid-induced β-cell apoptosis. Biochem Pharmacol 2017; 138:140-149. [PMID: 28522407 DOI: 10.1016/j.bcp.2017.05.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 05/11/2017] [Indexed: 02/07/2023]
Abstract
Pancreatic β-cell lipotoxicity is a central feature of the pathogenesis of type 2 diabetes. To study the mechanism by which fatty acids cause β-cell death and develop novel approaches to prevent it, a high-throughput screen on the β-cell line INS1 was carried out. The cells were exposed to palmitate to induce cell death and compounds that reversed palmitate-induced cytotoxicity were ascertained. Hits from the screen were analyzed by an increasingly more stringent testing funnel, ending with studies on primary human islets treated with palmitate. MAP4K4 inhibitors, which were not part of the screening libraries but were ascertained by a bioinformatics analysis, and the endocannabinoid anandamide were effective at inhibiting palmitate-induced apoptosis in INS1 cells as well as primary rat and human islets. These targets could serve as the starting point for the development of therapeutics for type 2 diabetes.
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Affiliation(s)
- Seung-Hee Lee
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Daniel Cunha
- ULB Center for Diabetes Research, Medical Faculty, Université Libre de Bruxelles (ULB), 808 Route de Lennik, B-1070 Brussels, Belgium
| | - Carlo Piermarocchi
- Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, USA
| | | | - Anthony Pinkerton
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Laurence Ladriere
- ULB Center for Diabetes Research, Medical Faculty, Université Libre de Bruxelles (ULB), 808 Route de Lennik, B-1070 Brussels, Belgium
| | - Piero Marchetti
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Decio L Eizirik
- ULB Center for Diabetes Research, Medical Faculty, Université Libre de Bruxelles (ULB), 808 Route de Lennik, B-1070 Brussels, Belgium
| | - Miriam Cnop
- ULB Center for Diabetes Research, Medical Faculty, Université Libre de Bruxelles (ULB), 808 Route de Lennik, B-1070 Brussels, Belgium; Division of Endocrinology, Erasmus Hospital, Université Libre de Bruxelles (ULB), B-1070 Brussels, Belgium
| | - Fred Levine
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA.
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Martínez E, Campos-Gómez J. Oxylipins produced by Pseudomonas aeruginosa promote biofilm formation and virulence. Nat Commun 2016; 7:13823. [PMID: 27929111 PMCID: PMC5155153 DOI: 10.1038/ncomms13823] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 11/02/2016] [Indexed: 01/14/2023] Open
Abstract
The oxygenation of unsaturated fatty acids by dioxygenases occurs in all kingdoms of life and produces physiologically important lipids called oxylipins. The biological roles of oxylipins have been extensively studied in animals, plants, algae and fungi, but remain largely unidentified in prokaryotes. The bacterium Pseudomonas aeruginosa displays a diol synthase activity that transforms several monounsaturated fatty acids into mono- and di-hydroxylated derivatives. Here we show that oxylipins derived from this activity inhibit flagellum-driven motility and upregulate type IV pilus-dependent twitching motility of P. aeruginosa. Consequently, these oxylipins promote bacterial organization in microcolonies, increasing the ability of P. aeruginosa to form biofilms in vitro and in vivo (in Drosophila flies). We also demonstrate that oxylipins produced by P. aeruginosa promote virulence in Drosophila flies and lettuce. Our study thus uncovers a role for prokaryotic oxylipins in the physiology and pathogenicity of bacteria.
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Affiliation(s)
- Eriel Martínez
- Southern Research, Department of Infectious Diseases, Drug Discovery Division, 2000 Ninth Ave South, Birmingham, Alabama 35205, USA
| | - Javier Campos-Gómez
- Southern Research, Department of Infectious Diseases, Drug Discovery Division, 2000 Ninth Ave South, Birmingham, Alabama 35205, USA
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50
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Shaheen A, Aljebali AMA. A hypothetical model to solve the controversy over the involvement of UCP2 in palmitate-induced β-cell dysfunction. Endocrine 2016; 54:276-283. [PMID: 27491555 DOI: 10.1007/s12020-016-1051-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 07/04/2016] [Indexed: 11/24/2022]
Abstract
The aim of this article is to solve an existing controversy over the involvement of uncoupling protein-2 in the impairment of glucose-stimulated insulin secretion induced by chronic exposure of β-cells to palmitate. We analyzed and compared the results of studies that support and that deny the involvement of uncoupling protein-2 in this impairment. We observed that this impairment could occur in multiple stages. We provide a model in which palmitate-induced impairment of glucose-stimulated insulin secretion is proposed to occur in two stages, early stage and late stage, depending on the integrity of electron supply (glycolysis and Krebs cycle) and transport system through electron transport chain after palmitate treatment. Prolonged exposure of β-cells to palmitate can impair this system. Early-stage impairment occurs due to uncoupling by uncoupling protein-2 when this system is still intact. When this system becomes impaired, late-stage impairment occurs mainly due to reduced glucose-stimulated adenosine triphosphate production independent of uncoupling by uncoupling protein-2. The change in glucose-stimulated oxygen uptake after palmitate treatment reflects the integrity of this system and can be used to differentiate between the two stages. Some β-cells lines and islets appear to be more resistant to palmitate-induced impairment of electron supply and transport system than others, and therefore early stage is prominent in the more resistant cell lines and less prominent or absent in the less resistant cell lines. This may help to resolve the pathogenesis of diabetes and to monitor the progression of palmitate-induced β-cell dysfunction.
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Affiliation(s)
- Alaa Shaheen
- Kafr El-Sharakwa Medical Center, Kafr El-Sharakwa, Aga, Dakahlia, Egypt.
| | - Ahmad M A Aljebali
- Department of Zoology, Faculty of Science, Omar Al Mukhtar University, Bayda, Libya
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