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Janikiewicz J, Dobosz AM, Majzner K, Bernas T, Dobrzyn A. Stearoyl-CoA desaturase 1 deficiency exacerbates palmitate-induced lipotoxicity by the formation of small lipid droplets in pancreatic β-cells. Biochim Biophys Acta Mol Basis Dis 2023; 1869:166711. [PMID: 37054998 DOI: 10.1016/j.bbadis.2023.166711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 03/28/2023] [Accepted: 03/30/2023] [Indexed: 04/15/2023]
Abstract
The accelerating accumulation of surplus lipids in the pancreas triggers structural and functional changes in type 2 diabetes-affected islets. Pancreatic β-cells exhibit a restricted capacity to store fat reservoirs in lipid droplets (LDs), which act as transient buffers to prevent lipotoxic stress. With the increasing incidence of obesity, growing interest has been seen in the intracellular regulation of LD metabolism for β-cell function. Stearoyl-CoA desaturase 1 (SCD1) is critical for producing unsaturated fatty acyl moieties for fluent storage into and out of LDs, likely affecting the overall rate of β-cell survival. We explored LD-associated composition and remodeling in SCD1-deprived INS-1E cells and in pancreatic islets in wildtype and SCD1-/- mice in the lipotoxic milieu. Deficiency in the enzymatic activity of SCD1 led to decrease in the size and number of LDs and the lower accumulation of neutral lipids. This occurred in parallel with a higher compactness and lipid order inside LDs, followed by changes in the saturation status and composition of fatty acids within core lipids and the phospholipid coat. The lipidome of LDs was enriched in 18:2n-6 and 20:4n-6 in β-cells and pancreatic islets. These rearrangements markedly contributed to differences in protein association with the LD surface. Our findings highlight an unexpected molecular mechanism by which SCD1 activity affects the morphology, composition and metabolism of LDs. We demonstrate that SCD1-dependent disturbances in LD enrichment can impact proper pancreatic β-cells and islet functioning, which may have considerable therapeutic value for the management of type 2 diabetes.
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Affiliation(s)
- Justyna Janikiewicz
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland.
| | - Aneta M Dobosz
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Katarzyna Majzner
- Faculty of Chemistry, Jagiellonian University, Cracow, Poland; Jagiellonian University, Jagiellonian Centre for Experimental Therapeutics (JCET), Cracow, Poland
| | - Tytus Bernas
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, USA
| | - Agnieszka Dobrzyn
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland.
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Dobosz AM, Janikiewicz J, Krogulec E, Dziewulska A, Ajduk A, Szpila M, Nieznańska H, Szczepankiewicz AA, Wypych D, Dobrzyn A. Inhibition of stearoyl-CoA desaturase 1 in the mouse impairs pancreatic islet morphogenesis and promotes loss of β-cell identity and α-cell expansion in the mature pancreas. Mol Metab 2022; 67:101659. [PMID: 36529318 PMCID: PMC9801219 DOI: 10.1016/j.molmet.2022.101659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 12/02/2022] [Accepted: 12/10/2022] [Indexed: 12/23/2022] Open
Abstract
Abnormalities that characterize the pathophysiology of type 2 diabetes (T2D) include deficiencies of β-cells and the expansion of α-cells in pancreatic islets, manifested by lower insulin release and glucagon oversecretion. The molecular mechanisms that determine intra-islet interactions between pancreatic α- and β-cells are still not fully understood. The present study showed that stearoyl-coenzyme A (CoA) desaturase 1 (SCD1), an enzyme that is implicated in fatty acid metabolism, serves as a checkpoint in the control of endocrine cell equilibrium in pancreatic islets. Our data showed that SCD1 activity is essential for proper α-cell and β-cell lineage determination during morphogenesis of the pancreas and the maintenance of mature β-cell identity. The inhibition of SCD1 expression/activity led to both a decrease in the expression of β-cell signature genes (e.g., Pdx1, Nkx6.1, MafA, and Neurod1, among others) and induction of the expression of the dedifferentiation marker Sox9 in mature pancreatic islets. The transcriptional repression of Pdx1 and MafA in SCD1-deficient β-cells was related to the excessive methylation of promoter regions of these transcription factors. In contrast, SCD1 ablation favored the formation of α-cells over β-cells throughout pancreas organogenesis and did not compromise α-cell identity in adult pancreatic islets. Such molecular changes that were caused by SCD1 downregulation resulted in the mislocalization of α-cells within the core of islets and increased the ratio of pancreatic α- to β-cell mass. This was followed by islet dysfunction, including impairments in glucose-stimulated insulin release, simultaneously with elevations of basal glucagon secretion. Altogether, these findings provide additional mechanistic insights into the role of SCD1 in the pathogenesis of T2D.
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Affiliation(s)
- Aneta M. Dobosz
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland,Corresponding author.
| | - Justyna Janikiewicz
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland.
| | - Ewelina Krogulec
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland.
| | - Anna Dziewulska
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland.
| | - Anna Ajduk
- Department of Embryology, Institute of Developmental Biology and Biomedical Sciences, Faculty of Biology, University of Warsaw, Warsaw, Poland.
| | - Marcin Szpila
- Department of Embryology, Institute of Developmental Biology and Biomedical Sciences, Faculty of Biology, University of Warsaw, Warsaw, Poland.
| | - Hanna Nieznańska
- Laboratory of Electron Microscopy, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland.
| | - Andrzej A. Szczepankiewicz
- Laboratory of Electron Microscopy, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Dorota Wypych
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland.
| | - Agnieszka Dobrzyn
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland.
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Szczepaniak P, Siedlinski M, Hodorowicz-Zaniewska D, Nosalski R, Mikolajczyk TP, Dobosz AM, Dikalova A, Dikalov S, Streb J, Gara K, Basta P, Krolczyk J, Sulicka-Grodzicka J, Jozefczuk E, Dziewulska A, Saju B, Laksa I, Chen W, Dormer J, Tomaszewski M, Maffia P, Czesnikiewicz-Guzik M, Crea F, Dobrzyn A, Moslehi J, Grodzicki T, Harrison DG, Guzik TJ. Breast cancer chemotherapy induces vascular dysfunction and hypertension through NOX4 dependent mechanism. J Clin Invest 2022; 132:149117. [PMID: 35617030 PMCID: PMC9246378 DOI: 10.1172/jci149117] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 05/19/2022] [Indexed: 11/17/2022] Open
Abstract
Cardiovascular disease is the major cause of morbidity and mortality in breast cancer survivors. Chemotherapy contributes to this risk. We aimed to define the mechanisms of long-term vascular dysfunction caused by neoadjuvant chemotherapy (NACT) and identify novel therapeutic targets.We studied arteries from postmenopausal women who had undergone breast cancer treatment using docetaxel, doxorubicin and cyclophosphamide (NACT), and women with no history of such treatment matched for key clinical parameters. Mechanisms were explored in wild-type and Nox4-/- mice and human microvascular endothelial cells.Endothelium-dependent vasodilatation is severely impaired in patients after NACT, while endothelium-independent responses remain normal. This was mimicked by 24-hour exposure of arteries to NACT agents ex-vivo. When applied individually, only docetaxel impaired endothelial function in human vessels. Mechanistic studies showed that NACT increased inhibitory eNOS phosphorylation of threonine 495 in a ROCK-dependent manner and augmented vascular superoxide and hydrogen peroxide production and NADPH oxidase activity. Docetaxel increased expression of NADPH oxidase NOX4 in endothelial and smooth muscle cells and NOX2 in the endothelium. NOX4 increase in human arteries may be mediated epigenetically by diminished DNA methylation of the NOX4 promoter. Docetaxel induced endothelial dysfunction and hypertension in mice. These were prevented in Nox4-/- and by pharmacological inhibition of Nox4 or Rock.Commonly used chemotherapeutic agents, and in particular, docetaxel, alter vascular function by promoting inhibitory phosphorylation of eNOS and enhancing ROS production by NADPH oxidases.
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Affiliation(s)
- Piotr Szczepaniak
- Department of Medicine, Collegium Medicum, Jagiellonian University, Krakow, Poland
| | - Mateusz Siedlinski
- Department of Medicine, Collegium Medicum, Jagiellonian University, Krakow, Poland
| | | | - Ryszard Nosalski
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Tomasz P Mikolajczyk
- Department of Medicine, Collegium Medicum, Jagiellonian University, Krakow, Poland
| | - Aneta M Dobosz
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Anna Dikalova
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University, Nashville, United States of America
| | - Sergey Dikalov
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University, Nashville, United States of America
| | - Joanna Streb
- Department of Oncology, Collegium Medicum, Jagiellonian University, Krakow, Poland
| | - Katarzyna Gara
- Department of Surgery, Collegium Medicum, Jagiellonian University, Krakow, Poland
| | - Pawel Basta
- Department of Gynecology and Gynecological Oncology, Collegium Medicum, Jagiellonian University, Krakow, Poland
| | - Jaroslaw Krolczyk
- Department of Internal Medicine and Gerontology, Collegium Medicum, Jagiellonian University, Krakow, Poland
| | | | - Ewelina Jozefczuk
- Department of Medicine, Collegium Medicum, Jagiellonian University, Krakow, Poland
| | - Anna Dziewulska
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Blessy Saju
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Iwona Laksa
- Department of Oncology, Collegium Medicum, Jagiellonian University, Krakow, Poland
| | - Wei Chen
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University, Nashville, United States of America
| | - John Dormer
- Department of Cellular Pathology, University Hospitals of Leicester, Leicester, United Kingdom
| | - Maciej Tomaszewski
- Division of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom
| | - Pasquale Maffia
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Marta Czesnikiewicz-Guzik
- Department of Periodontology and Oral Sciences Research Group, University of Glasgow, Glasgow, United Kingdom
| | - Filippo Crea
- Department of Cardiovascular and Thoracic Sciences, University of the Sacred Heart, Rome, Italy
| | - Agnieszka Dobrzyn
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Javid Moslehi
- University of California San Fransisco, San Francisco, United States of America
| | - Tomasz Grodzicki
- Department of Internal Medicine and Gerontology, Collegium Medicum, Jagiellonian University, Krakow, Poland
| | - David G Harrison
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University, Nashville, United States of America
| | - Tomasz J Guzik
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
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Dobosz AM, Janikiewicz J, Borkowska AM, Dziewulska A, Lipiec E, Dobrzyn P, Kwiatek WM, Dobrzyn A. Stearoyl-CoA Desaturase 1 Activity Determines the Maintenance of DNMT1-Mediated DNA Methylation Patterns in Pancreatic β-Cells. Int J Mol Sci 2020; 21:ijms21186844. [PMID: 32961871 PMCID: PMC7555428 DOI: 10.3390/ijms21186844] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 09/11/2020] [Accepted: 09/16/2020] [Indexed: 11/16/2022] Open
Abstract
Metabolic stress, such as lipotoxicity, affects the DNA methylation profile in pancreatic β-cells and thus contributes to β-cell failure and the progression of type 2 diabetes (T2D). Stearoyl-CoA desaturase 1 (SCD1) is a rate-limiting enzyme that is involved in monounsaturated fatty acid synthesis, which protects pancreatic β-cells against lipotoxicity. The present study found that SCD1 is also required for the establishment and maintenance of DNA methylation patterns in β-cells. We showed that SCD1 inhibition/deficiency caused DNA hypomethylation and changed the methyl group distribution within chromosomes in β-cells. Lower levels of DNA methylation in SCD1-deficient β-cells were followed by lower levels of DNA methyltransferase 1 (DNMT1). We also found that the downregulation of SCD1 in pancreatic β-cells led to the activation of adenosine monophosphate-activated protein kinase (AMPK) and an increase in the activity of the NAD-dependent deacetylase sirtuin-1 (SIRT1). Furthermore, the physical association between DNMT1 and SIRT1 stimulated the deacetylation of DNMT1 under conditions of SCD1 inhibition/downregulation, suggesting a mechanism by which SCD1 exerts control over DNMT1. We also found that SCD1-deficient β-cells that were treated with compound c, an inhibitor of AMPK, were characterized by higher levels of both global DNA methylation and DNMT1 protein expression compared with untreated cells. Therefore, we found that activation of the AMPK/SIRT1 signaling pathway mediates the effect of SCD1 inhibition/deficiency on DNA methylation status in pancreatic β-cells. Altogether, these findings suggest that SCD1 is a gatekeeper that protects β-cells against the lipid-derived loss of DNA methylation and provide mechanistic insights into the mechanism by which SCD1 regulates DNA methylation patterns in β-cells and T2D-relevant tissues.
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Affiliation(s)
- Aneta M. Dobosz
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (A.M.D.); (J.J.); (A.D.)
| | - Justyna Janikiewicz
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (A.M.D.); (J.J.); (A.D.)
| | - Anna M. Borkowska
- Division of Interdisciplinary Research, Institute of Nuclear Physics, Polish Academy of Sciences, 31-342 Krakow, Poland; (A.M.B.); (E.L.); (W.M.K.)
| | - Anna Dziewulska
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (A.M.D.); (J.J.); (A.D.)
| | - Ewelina Lipiec
- Division of Interdisciplinary Research, Institute of Nuclear Physics, Polish Academy of Sciences, 31-342 Krakow, Poland; (A.M.B.); (E.L.); (W.M.K.)
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, 30-348 Krakow, Poland
| | - Pawel Dobrzyn
- Laboratory of Molecular Medical Biochemistry, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland;
| | - Wojciech M. Kwiatek
- Division of Interdisciplinary Research, Institute of Nuclear Physics, Polish Academy of Sciences, 31-342 Krakow, Poland; (A.M.B.); (E.L.); (W.M.K.)
| | - Agnieszka Dobrzyn
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (A.M.D.); (J.J.); (A.D.)
- Correspondence:
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5
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Dziewulska A, Dobosz AM, Dobrzyn A, Smolinska A, Kolczynska K, Ntambi JM, Dobrzyn P. SCD1 regulates the AMPK/SIRT1 pathway and histone acetylation through changes in adenine nucleotide metabolism in skeletal muscle. J Cell Physiol 2019; 235:1129-1140. [PMID: 31241768 DOI: 10.1002/jcp.29026] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 06/11/2019] [Indexed: 01/06/2023]
Abstract
Stearoyl-CoA desaturase (SCD) is a rate-limiting enzyme that catalyzes the synthesis of monounsaturated fatty acids. It plays an important role in regulating skeletal muscle metabolism. Lack of the SCD1 gene increases the rate of fatty acid β-oxidation through activation of the AMP-activated protein kinase (AMPK) pathway and the upregulation of genes that are related to fatty acid oxidation. The mechanism of AMPK activation under conditions of SCD1 deficiency has been unclear. In the present study, we found that the ablation/inhibition of SCD1 led to AMPK activation in skeletal muscle through an increase in AMP levels whereas muscle-specific SCD1 overexpression decreased both AMPK phosphorylation and the adenosine monophosphate/adenosine triphosphate (AMP/ATP) ratio. Changes in AMPK phosphorylation that were caused by SCD1 down- and upregulation affected NAD+ levels following changes in NAD+ -dependent deacetylase sirtuin-1 (SIRT1) activity and histone 3 (H3K9) acetylation and methylation status. Moreover, mice with muscle-targeted overexpression of SCD1 were more susceptible to high-fat diet-induced lipid accumulation and the development of insulin resistance compared with wild-type mice. These data show that SCD1 is involved in nucleotide (ATP and NAD+ ) metabolism and suggest that the SCD1-dependent regulation of muscle steatosis and insulin sensitivity are mediated by cooperation between AMPK- and SIRT1-regulated pathways. Altogether, the present study reveals a novel mechanism that links SCD1 with the maintenance of metabolic homeostasis and insulin sensitivity in skeletal muscle.
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Affiliation(s)
- Anna Dziewulska
- Department of Biochemistry, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Aneta M Dobosz
- Department of Biochemistry, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Agnieszka Dobrzyn
- Department of Biochemistry, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Agnieszka Smolinska
- Department of Biochemistry, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Katarzyna Kolczynska
- Department of Biochemistry, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - James M Ntambi
- Departments of Biochemistry and Nutritional Sciences, University of Wisconsin-Madison, Madison, WI, USA
| | - Pawel Dobrzyn
- Department of Biochemistry, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
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6
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Dobosz AM, Dziewulska A, Dobrzyń A. Spotlight on epigenetics as a missing link between obesity and type 2 diabetes. Postepy Biochem 2018; 64:157-165. [PMID: 30656898 DOI: 10.18388/pb.2018_126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 09/21/2018] [Indexed: 11/10/2022]
Abstract
Type 2 diabetes (T2D) is a complex disorder that is caused by a combination of genetic, epigenetic, and environmental factors. β-cell failure and insulin resistance in peripheral tissues that are induced by lipid overload are main hallmarks of T2D. The mechanisms that link obesity-driven alterations of lipid metabolism and T2D are still elusive, thereby impeding the development of effective prevention and treatment strategies. Although genetic variants that have been identified in high-throughput studies comprise an appreciable proportion of the genetic component of T2D, they explain < 20% of the estimated heritability of T2D. A growing body of evidence suggests an intrinsic role for epigenetic modifications in the pathogenesis of T2D. The epigenetic regulation of gene expression in tissues that play a key role in the obesity-related development of T2D has been demonstrated, including PDX1 in pancreatic islets, PPARGC1A in skeletal muscles, ADIPOQ in adipose tissue, and TXNIP in the liver. The present review summarizes our current knowledge of crosstalk between the epigenetic control of gene expression, particularly via DNA methylation, toxic lipid mediators, and the pathogenesis of obesity-related T2D.
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Affiliation(s)
- Aneta M Dobosz
- Instytut Biologii Doświadczalnej PAN im. M. Nenckiego w Warszawie
| | - Anna Dziewulska
- Instytut Biologii Doświadczalnej PAN im. M. Nenckiego w Warszawie
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7
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Dziewulska A, Dobosz AM, Dobrzyn A. High-Throughput Approaches onto Uncover (Epi)Genomic Architecture of Type 2 Diabetes. Genes (Basel) 2018; 9:E374. [PMID: 30050001 PMCID: PMC6115814 DOI: 10.3390/genes9080374] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Revised: 07/20/2018] [Accepted: 07/23/2018] [Indexed: 12/20/2022] Open
Abstract
Type 2 diabetes (T2D) is a complex disorder that is caused by a combination of genetic, epigenetic, and environmental factors. High-throughput approaches have opened a new avenue toward a better understanding of the molecular bases of T2D. A genome-wide association studies (GWASs) identified a group of the most common susceptibility genes for T2D (i.e., TCF7L2, PPARG, KCNJ1, HNF1A, PTPN1, and CDKAL1) and illuminated novel disease-causing pathways. Next-generation sequencing (NGS)-based techniques have shed light on rare-coding genetic variants that account for an appreciable fraction of T2D heritability (KCNQ1 and ADRA2A) and population risk of T2D (SLC16A11, TPCN2, PAM, and CCND2). Moreover, single-cell sequencing of human pancreatic islets identified gene signatures that are exclusive to α-cells (GCG, IRX2, and IGFBP2) and β-cells (INS, ADCYAP1, INS-IGF2, and MAFA). Ongoing epigenome-wide association studies (EWASs) have progressively defined links between epigenetic markers and the transcriptional activity of T2D target genes. Differentially methylated regions were found in TCF7L2, THADA, KCNQ1, TXNIP, SOCS3, SREBF1, and KLF14 loci that are related to T2D. Additionally, chromatin state maps in pancreatic islets were provided and several non-coding RNAs (ncRNA) that are key to T2D pathogenesis were identified (i.e., miR-375). The present review summarizes major progress that has been made in mapping the (epi)genomic landscape of T2D within the last few years.
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Affiliation(s)
- Anna Dziewulska
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 02-093 Warsaw, Poland.
| | - Aneta M Dobosz
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 02-093 Warsaw, Poland.
| | - Agnieszka Dobrzyn
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 02-093 Warsaw, Poland.
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8
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Bocian-Ostrzycka KM, Łasica AM, Dunin-Horkawicz S, Grzeszczuk MJ, Drabik K, Dobosz AM, Godlewska R, Nowak E, Collet JF, Jagusztyn-Krynicka EK. Functional and evolutionary analyses of Helicobacter pylori HP0231 (DsbK) protein with strong oxidative and chaperone activity characterized by a highly diverged dimerization domain. Front Microbiol 2015; 6:1065. [PMID: 26500620 PMCID: PMC4597128 DOI: 10.3389/fmicb.2015.01065] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 09/16/2015] [Indexed: 12/15/2022] Open
Abstract
Helicobacter pylori does not encode the classical DsbA/DsbB oxidoreductases that are crucial for oxidative folding of extracytoplasmic proteins. Instead, this microorganism encodes an untypical two proteins playing a role in disulfide bond formation – periplasmic HP0231, which structure resembles that of EcDsbC/DsbG, and its redox partner, a membrane protein HpDsbI (HP0595) with a β-propeller structure. The aim of presented work was to assess relations between HP0231 structure and function. We showed that HP0231 is most closely related evolutionarily to the catalytic domain of DsbG, even though it possesses a catalytic motif typical for canonical DsbA proteins. Similarly, the highly diverged N-terminal dimerization domain is homologous to the dimerization domain of DsbG. To better understand the functioning of this atypical oxidoreductase, we examined its activity using in vivo and in vitro experiments. We found that HP0231 exhibits oxidizing and chaperone activities but no isomerizing activity, even though H. pylori does not contain a classical DsbC. We also show that HP0231 is not involved in the introduction of disulfide bonds into HcpC (Helicobactercysteine-rich protein C), a protein involved in the modulation of the H. pylori interaction with its host. Additionally, we also constructed a truncated version of HP0231 lacking the dimerization domain, denoted HP0231m, and showed that it acts in Escherichia coli cells in a DsbB-dependent manner. In contrast, HP0231m and classical monomeric EcDsbA (E. coli DsbA protein) were both unable to complement the lack of HP0231 in H. pylori cells, though they exist in oxidized forms. HP0231m is inactive in the insulin reduction assay and possesses high chaperone activity, in contrast to EcDsbA. In conclusion, HP0231 combines oxidative functions characteristic of DsbA proteins and chaperone activity characteristic of DsbC/DsbG, and it lacks isomerization activity.
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Affiliation(s)
- Katarzyna M Bocian-Ostrzycka
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw Warsaw, Poland
| | - Anna M Łasica
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology Warsaw, Poland
| | - Stanisław Dunin-Horkawicz
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology Warsaw, Poland
| | - Magdalena J Grzeszczuk
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw Warsaw, Poland
| | - Karolina Drabik
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw Warsaw, Poland
| | - Aneta M Dobosz
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw Warsaw, Poland
| | - Renata Godlewska
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw Warsaw, Poland
| | - Elżbieta Nowak
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology Warsaw, Poland
| | - Jean-Francois Collet
- de Duve Institute, Université catholique de Louvain (UCL)/Walloon Excellence in Life Sciences and Biotechnology Brussels, Belgium
| | - Elżbieta K Jagusztyn-Krynicka
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw Warsaw, Poland
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