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Chakraborty R, Mukherjee AK, Bala A. Breakthroughs in road mapping IL-35 mediated immunotherapy for type-1 and autoimmune diabetes mellitus. Cytokine 2024; 181:156692. [PMID: 38986251 DOI: 10.1016/j.cyto.2024.156692] [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: 04/05/2024] [Revised: 05/22/2024] [Accepted: 07/05/2024] [Indexed: 07/12/2024]
Abstract
IL-35 is a recently discovered protein made up of IL-12α and IL-27β chains. It is encoded by IL12A and EBI3 genes. Interest in researching IL-35 has significantly increased in recent years, as evidenced by numerous scientific publications. Diabetes is on the rise globally, causing more illness and death in developing countries. The International Diabetes Federation (IDF) reports that diabetes is increasingly affecting children and teenagers, with varying rates across different regions. Therefore, scientists seek new diabetes treatments despite the growth of drug research. Recent research aims to emphasize IL-35 as a critical regulator of diabetes, especially type 1 and autoimmune diabetes. This review provides an overview of recent research on IL-35 and its link to diabetes and its associated complications. Studies suggest that IL-35 can offer protection against type-1 diabetes and autoimmune diabetes by regulating macrophage polarization, T-cell-related cytokines, and regulatory B cells (Bregs). This review will hopefully assist biomedical scientists in exploring the potential role of IL-35-mediated immunotherapy in treating diabetes. However, further research is necessary to determine the exact mechanism and plan clinical trials.
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Affiliation(s)
- Ratul Chakraborty
- Pharmacology and Drug Discovery Research Laboratory, Division of Life Sciences, Institute of Advanced Study in Science and Technology (IASST), Vigyan Path, Guwahati 781035, Assam, India; Academy of Scientific and Innovative Research (AcSIR), AcSIR (an Indian Institute of National Importance), Sector 19, Kamla Nehru Nagar, Ghaziabad, Uttar Pradesh 201002, India
| | - Ashis K Mukherjee
- Microbial Biotechnology and Protein Research Laboratory, Division of Life Sciences, Institute of Advanced Study in Science and Technology (IASST), Vigyan Path, Guwahati 781035, Assam, India
| | - Asis Bala
- Pharmacology and Drug Discovery Research Laboratory, Division of Life Sciences, Institute of Advanced Study in Science and Technology (IASST), Vigyan Path, Guwahati 781035, Assam, India; Academy of Scientific and Innovative Research (AcSIR), AcSIR (an Indian Institute of National Importance), Sector 19, Kamla Nehru Nagar, Ghaziabad, Uttar Pradesh 201002, India.
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2
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Jollet M, Tramontana F, Jiang LQ, Borg ML, Savikj M, Kuefner MS, Massart J, de Castro Barbosa T, Mannerås-Holm L, Checa A, Pillon NJ, Chibalin AV, Björnholm M, Zierath JR. Diacylglycerol kinase delta overexpression improves glucose clearance and protects against the development of obesity. Metabolism 2024; 158:155939. [PMID: 38843995 DOI: 10.1016/j.metabol.2024.155939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2024] [Revised: 05/22/2024] [Accepted: 05/28/2024] [Indexed: 07/06/2024]
Abstract
BACKGROUND AND AIM Diacylglycerol kinase (DGK) isoforms catalyze an enzymatic reaction that removes diacylglycerol (DAG) and thereby terminates protein kinase C signaling by converting DAG to phosphatidic acid. DGKδ (type II isozyme) downregulation causes insulin resistance, metabolic inflexibility, and obesity. Here we determined whether DGKδ overexpression prevents these metabolic impairments. METHODS We generated a transgenic mouse model overexpressing human DGKδ2 under the myosin light chain promoter (DGKδ TG). We performed deep metabolic phenotyping of DGKδ TG mice and wild-type littermates fed chow or high-fat diet (HFD). Mice were also provided free access to running wheels to examine the effects of DGKδ overexpression on exercise-induced metabolic outcomes. RESULTS DGKδ TG mice were leaner than wild-type littermates, with improved glucose tolerance and increased skeletal muscle glycogen content. DGKδ TG mice were protected against HFD-induced glucose intolerance and obesity. DGKδ TG mice had reduced epididymal fat and enhanced lipolysis. Strikingly, DGKδ overexpression recapitulated the beneficial effects of exercise on metabolic outcomes. DGKδ overexpression and exercise had a synergistic effect on body weight reduction. Microarray analysis of skeletal muscle revealed common gene ontology signatures of exercise and DGKδ overexpression that were related to lipid storage, extracellular matrix, and glycerophospholipids biosynthesis pathways. CONCLUSION Overexpression of DGKδ induces adaptive changes in both skeletal muscle and adipose tissue, resulting in protection against HFD-induced obesity. DGKδ overexpression recapitulates exercise-induced adaptations on energy homeostasis and skeletal muscle gene expression profiles.
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Affiliation(s)
- Maxence Jollet
- Department of Molecular Medicine and Surgery, Section for Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Flavia Tramontana
- Department of Physiology and Pharmacology, Section for Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Lake Q Jiang
- Department of Physiology and Pharmacology, Section for Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Melissa L Borg
- Department of Physiology and Pharmacology, Section for Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Mladen Savikj
- Department of Molecular Medicine and Surgery, Section for Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Michael S Kuefner
- Department of Molecular Medicine and Surgery, Section for Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Julie Massart
- Department of Molecular Medicine and Surgery, Section for Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Thais de Castro Barbosa
- Department of Physiology and Pharmacology, Section for Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Louise Mannerås-Holm
- Department of Physiology and Pharmacology, Section for Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Antonio Checa
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Nicolas J Pillon
- Department of Physiology and Pharmacology, Section for Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Alexander V Chibalin
- Department of Molecular Medicine and Surgery, Section for Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Marie Björnholm
- Department of Molecular Medicine and Surgery, Section for Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Juleen R Zierath
- Department of Molecular Medicine and Surgery, Section for Integrative Physiology, Karolinska Institutet, Stockholm, Sweden; Department of Physiology and Pharmacology, Section for Integrative Physiology, Karolinska Institutet, Stockholm, Sweden.
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3
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Changkakoti L, Das JM, Borah R, Rajabalaya R, David SR, Balaraman AK, Pramanik S, Haldar PK, Bala A. Protein Kinase C (PKC)-mediated TGF-β Regulation in Diabetic Neuropathy: Emphasis on Neuro-inflammation and Allodynia. Endocr Metab Immune Disord Drug Targets 2024; 24:777-788. [PMID: 37937564 DOI: 10.2174/0118715303262824231024104849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 08/08/2023] [Accepted: 09/25/2023] [Indexed: 11/09/2023]
Abstract
According to the World Health Organization (WHO), diabetes has been increasing steadily over the past few decades. In developing countries, it is the cause of increased morbidity and mortality. Diabetes and its complications are associated with education, occupation, and income across all levels of socioeconomic status. Factors, such as hyperglycemia, social ignorance, lack of proper health knowledge, and late access to medical care, can worsen diabetic complications. Amongst the complications, neuropathic pain and inflammation are considered the most common causes of morbidity for common populations. This review is focused on exploring protein kinase C (PKC)-mediated TGF-946; regulation in diabetic complications with particular emphasis on allodynia. The role of PKC-triggered TGF-946; in diabetic neuropathy is not well explored. This review will provide a better understanding of the PKC-mediated TGF-946; regulation in diabetic neuropathy with several schematic illustrations. Neuroinflammation and associated hyperalgesia and allodynia during microvascular complications in diabetes are scientifically illustrated in this review. It is hoped that this review will facilitate biomedical scientists to better understand the etiology and target drugs effectively to manage diabetes and diabetic neuropathy.
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Affiliation(s)
- Liza Changkakoti
- Pharmacology and Drug Discovery Research Laboratory, Division of Life Sciences, Institute of Advanced Study in Science and Technology (IASST), An Autonomous Institute Under - Department of Science & Technology (Govt. of India) Vigyan Path, Guwahati, PIN- 781035 Assam, India
| | - Jitu Mani Das
- Pharmacology and Drug Discovery Research Laboratory, Division of Life Sciences, Institute of Advanced Study in Science and Technology (IASST), An Autonomous Institute Under - Department of Science & Technology (Govt. of India) Vigyan Path, Guwahati, PIN- 781035 Assam, India
| | - Rajiv Borah
- Department of Mechanical, Manufacturing and Biomedical Engineering, Trinity College Dublin, The University of Dublin, Dublin, Ireland
| | - Rajan Rajabalaya
- PAPRSB Institute of Health Sciences, Universiti Brunei Darussalam, BE 1410 Bandar Seri Begawan, Brunei Darussalam
| | - Sheba Rani David
- School of Pharmacology, University of Wyoming, Laramie, Wyoming, 82071, USA
| | - Ashok Kumar Balaraman
- Faculty of Pharmacy, MAHSA University, Bandar Saujana Putra, 42610, Jenjarom, Selangor, Malaysia
| | - Subrata Pramanik
- Jyoti and Bhupat Mehta School of Health Sciences & Technology, Indian Institute of Technology (IIT), Guwahati, Assam- 781039, India
| | - Pallab Kanti Haldar
- Department of Pharmaceutical Technology, Division of Pharmacology & Toxicology, Jadavpur University, Kolkata, 700032, India
| | - Asis Bala
- Pharmacology and Drug Discovery Research Laboratory, Division of Life Sciences, Institute of Advanced Study in Science and Technology (IASST), An Autonomous Institute Under - Department of Science & Technology (Govt. of India) Vigyan Path, Guwahati, PIN- 781035 Assam, India
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4
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Suzuki R, Murakami C, Dilimulati K, Atsuta-Tsunoda K, Kawai T, Sakane F. Human sphingomyelin synthase 1 generates diacylglycerol in the presence and absence of ceramide via multiple enzymatic activities. FEBS Lett 2023; 597:2672-2686. [PMID: 37715942 DOI: 10.1002/1873-3468.14735] [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: 06/29/2023] [Revised: 08/24/2023] [Accepted: 09/01/2023] [Indexed: 09/18/2023]
Abstract
Sphingomyelin (SM) synthase 1 (SMS1), which is involved in lipodystrophy, deafness, and thrombasthenia, generates diacylglycerol (DG) and SM using phosphatidylcholine (PC) and ceramide as substrates. Here, we found that SMS1 possesses DG-generating activities via hydrolysis of PC and phosphatidylethanolamine (PE) in the absence of ceramide and ceramide phosphoethanolamine synthase (CPES) activity. In the presence of the same concentration (4.7 mol%) of PC and ceramide, the amounts of DG produced by SMS and PC-phospholipase C (PLC) activities of SMS1 were approximately 65% and 35% of total DG production, respectively. PC-PLC activity showed substrate selectivity for saturated and/or monounsaturated fatty acid-containing PC species. A PC-PLC/SMS inhibitor, D609, inhibited only SMS activity. Mn2+ inhibited only PC-PLC activity. Intriguingly, DG attenuated SMS/CPES activities. Our study indicates that SMS1 is a unique enzyme with PC-PLC/PE-PLC/SMS/CPES activities.
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Affiliation(s)
- Rika Suzuki
- Department of Chemistry, Graduate School of Science, Chiba University, Japan
| | - Chiaki Murakami
- Department of Chemistry, Graduate School of Science, Chiba University, Japan
- Institute for Advanced Academic Research, Chiba University, Japan
| | - Kamila Dilimulati
- Department of Chemistry, Graduate School of Science, Chiba University, Japan
| | | | - Takuma Kawai
- Department of Chemistry, Graduate School of Science, Chiba University, Japan
| | - Fumio Sakane
- Department of Chemistry, Graduate School of Science, Chiba University, Japan
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5
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Su H, Guo H, Qiu X, Lin TY, Qin C, Celio G, Yong P, Senders M, Han X, Bernlohr DA, Chen X. Lipocalin 2 regulates mitochondrial phospholipidome remodeling, dynamics, and function in brown adipose tissue in male mice. Nat Commun 2023; 14:6729. [PMID: 37872178 PMCID: PMC10593768 DOI: 10.1038/s41467-023-42473-2] [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: 11/17/2022] [Accepted: 10/11/2023] [Indexed: 10/25/2023] Open
Abstract
Mitochondrial function is vital for energy metabolism in thermogenic adipocytes. Impaired mitochondrial bioenergetics in brown adipocytes are linked to disrupted thermogenesis and energy balance in obesity and aging. Phospholipid cardiolipin (CL) and phosphatidic acid (PA) jointly regulate mitochondrial membrane architecture and dynamics, with mitochondria-associated endoplasmic reticulum membranes (MAMs) serving as the platform for phospholipid biosynthesis and metabolism. However, little is known about the regulators of MAM phospholipid metabolism and their connection to mitochondrial function. We discover that LCN2 is a PA binding protein recruited to the MAM during inflammation and metabolic stimulation. Lcn2 deficiency disrupts mitochondrial fusion-fission balance and alters the acyl-chain composition of mitochondrial phospholipids in brown adipose tissue (BAT) of male mice. Lcn2 KO male mice exhibit an increase in the levels of CLs containing long-chain polyunsaturated fatty acids (LC-PUFA), a decrease in CLs containing monounsaturated fatty acids, resulting in mitochondrial dysfunction. This dysfunction triggers compensatory activation of peroxisomal function and the biosynthesis of LC-PUFA-containing plasmalogens in BAT. Additionally, Lcn2 deficiency alters PA production, correlating with changes in PA-regulated phospholipid-metabolizing enzymes and the mTOR signaling pathway. In conclusion, LCN2 plays a critical role in the acyl-chain remodeling of phospholipids and mitochondrial bioenergetics by regulating PA production and its function in activating signaling pathways.
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Affiliation(s)
- Hongming Su
- Department of Food Science and Nutrition, University of Minnesota-Twin Cities, St. Paul, MN, 55108, USA
| | - Hong Guo
- Department of Food Science and Nutrition, University of Minnesota-Twin Cities, St. Paul, MN, 55108, USA
| | - Xiaoxue Qiu
- Department of Food Science and Nutrition, University of Minnesota-Twin Cities, St. Paul, MN, 55108, USA
| | - Te-Yueh Lin
- Department of Food Science and Nutrition, University of Minnesota-Twin Cities, St. Paul, MN, 55108, USA
| | - Chao Qin
- Barshop Institute for Longevity and Aging Studies, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229-3900, USA
| | - Gail Celio
- University Imaging Centers, University of Minnesota-Twin Cities, Minneapolis, MN, 55455, USA
| | - Peter Yong
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota-Twin Cities, Minneapolis, MN, 55455, USA
| | - Mark Senders
- University Imaging Centers, University of Minnesota-Twin Cities, Minneapolis, MN, 55455, USA
| | - Xianlin Han
- Barshop Institute for Longevity and Aging Studies, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229-3900, USA
| | - David A Bernlohr
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota-Twin Cities, Minneapolis, MN, 55455, USA
| | - Xiaoli Chen
- Department of Food Science and Nutrition, University of Minnesota-Twin Cities, St. Paul, MN, 55108, USA.
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6
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Numagami Y, Hoshino F, Murakami C, Ebina M, Sakane F. Distinct regions of Praja-1 E3 ubiquitin-protein ligase selectively bind to docosahexaenoic acid-containing phosphatidic acid and diacylglycerol kinase δ. Biochim Biophys Acta Mol Cell Biol Lipids 2023; 1868:159265. [PMID: 36528254 DOI: 10.1016/j.bbalip.2022.159265] [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: 08/30/2022] [Revised: 11/18/2022] [Accepted: 12/06/2022] [Indexed: 12/23/2022]
Abstract
1-Stearoyl-2-docosahexaenoyl (18:0/22:6)-phosphatidic acid (PA) interacts with and activates Praja-1 E3 ubiquitin-protein ligase (full length: 615 aa) to ubiquitinate and degrade the serotonin transporter (SERT). SERT modulates serotonergic system activity and is a therapeutic target for depression, autism, obsessive-compulsive disorder, schizophrenia and Alzheimer's disease. Moreover, diacylglycerol kinase (DGK) δ2 (full length: 1214 aa) interacts with Praja-1 in addition to SERT and generates 18:0/22:6-PA, which binds and activates Praja-1. In the present study, we investigated the interaction of Praja-1 with 18:0/22:6-PA and DGKδ2 in more detail. We first found that the N-terminal one-third region (aa 1-224) of Praja-1 bound to 18:0/22:6-PA and that Lys141 in the region was critical for binding to 18:0/22:6-PA. In contrast, the C-terminal catalytic domain of Praja-1 (aa 446-615) interacted with DGKδ2. Additionally, the N-terminal half of the catalytic domain (aa 309-466) of DGKδ2 intensely bound to Praja-1. Moreover, the N-terminal region containing the pleckstrin homology and C1 domains (aa 1-308) and the C-terminal half of the catalytic domain (aa 762-939) of DGKδ2 weakly associated with Praja-1. Taken together, these results reveal new functions of the N-terminal (aa 1-224) and C-terminal (aa 446-615) regions of Praja-1 and the N-terminal half of the catalytic region (aa 309-466) of DGKδ2 as regulatory domains. Moreover, it is likely that the DGKδ2-Praja-1-SERT heterotrimer proximally arranges the 18:0/22:6-PA-producing catalytic domain of DGKδ2, the 18:0/22:6-PA-binding regulatory domain of Praja-1, the ubiquitin-protein ligase catalytic domain of Praja-1 and the ubiquitination acceptor site-containing SERT C-terminal region.
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Affiliation(s)
- Yuki Numagami
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Fumi Hoshino
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Chiaki Murakami
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan; Institute for Advanced Academic Research, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Masayuki Ebina
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Fumio Sakane
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
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7
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Grune T, Schnell V, Jung T. High glucose leads to redistribution of the proteasomal system. Biofactors 2023. [PMID: 36757058 DOI: 10.1002/biof.1937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 12/27/2022] [Indexed: 02/10/2023]
Abstract
The impact of high glucose on the cellular redox state, causing both induction of antioxidative systems and also enhanced protein oxidation is discussed for a long time. It is established that elevated glucose levels are disrupting the cellular proteostasis and influencing the proteasomal system. However, it is still unresolved whether this is due to a reaction of the cellular proteasomal system towards the high glucose or whether this is a secondary reaction to inflammatory stimuli. Therefore, we used a dermal fibroblast cell line exposed to high glucose in order to reveal whether a response of the proteasomal system takes place. We investigated the α4 and the inducible iβ5 subunits of the 20S proteasome, as well as the Rpn1-subunit of the 19S proteasomal regulator complex, measured activity of the 20S, 20S1, and 26S proteasome and detected as well changes in expression as a redistribution into the nucleus. Interestingly, while the activity of the proteasomal forms rather decreased under high glucose treatment; higher expression levels of components of the proteasomal system and higher concentrations of protein-bound 3-nitrotyrosine and Nrf2 (nuclear factor [erythroid-derived 2]-like 2) were detected. However, no change in the cytosol-nucleus distribution could be detected for most of the quantified parameters. We concluded that high glucose alone, without additional inflammatory stimuli, provokes a regulatory response on the ubiquitin-proteasomal system.
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Affiliation(s)
- Tilman Grune
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbrücke, Nuthetal, Germany
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany
- German Center for Cardiovascular Research (DZHK), Berlin, Germany
- Institute of Nutrition, University of Potsdam, Nuthetal, Germany
- Department of Physiological Chemistry, Faculty of Chemistry, University of Vienna, Vienna, Austria
| | - Vanessa Schnell
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbrücke, Nuthetal, Germany
| | - Tobias Jung
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbrücke, Nuthetal, Germany
- German Center for Cardiovascular Research (DZHK), Berlin, Germany
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8
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Sakai H, Matsumoto K, Urano T, Sakane F. Myristic acid selectively augments β-tubulin levels in C2C12 myotubes via diacylglycerol kinase δ. FEBS Open Bio 2022; 12:1788-1796. [PMID: 35856166 PMCID: PMC9527581 DOI: 10.1002/2211-5463.13466] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Revised: 06/29/2022] [Accepted: 07/19/2022] [Indexed: 12/14/2022] Open
Abstract
Effective amelioration of type II diabetes requires therapies that increase both glucose uptake activity per cell and skeletal muscle mass. Myristic acid (14:0) increases diacylglycerol kinase (DGK) δ protein levels and enhances glucose uptake in myotubes in a DGKδ-dependent manner. However, it is still unclear whether myristic acid treatment affects skeletal muscle mass. In this study, we found that myristic acid treatment increased the protein level of β-tubulin, which constitutes microtubules and is closely related to muscle mass, in C2C12 myotubes but not in the proliferation stage in C2C12 myoblasts. However, lauric (12:0), palmitic (16:0) and oleic (18:1) acids failed to affect DGKδ and β-tubulin protein levels in C2C12 myotubes. Moreover, knockdown of DGKδ by siRNA significantly inhibited the increased protein level of β-tubulin in the presence of myristic acid, suggesting that the increase in β-tubulin protein by myristic acid depends on DGKδ. These results indicate that myristic acid selectively affects β-tubulin protein levels in C2C12 myotubes via DGKδ, suggesting that this fatty acid improves skeletal muscle mass in addition to increasing glucose uptake activity per cell.
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Affiliation(s)
- Hiromichi Sakai
- Department of Biosignaling and Radioisotope Experiment, Interdisciplinary Center for Science Research, Organization for Research and Academic InformationShimane UniversityIzumoJapan
| | - Ken‐ichi Matsumoto
- Department of Biosignaling and Radioisotope Experiment, Interdisciplinary Center for Science Research, Organization for Research and Academic InformationShimane UniversityIzumoJapan
| | - Takeshi Urano
- Department of BiochemistryShimane University School of MedicineIzumoJapan
| | - Fumio Sakane
- Department of Chemistry, Graduate School of ScienceChiba UniversityJapan
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9
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Sato T, Ishiwatari C, Kaneko YK, Ishikawa Y, Kimura Y, Watanabe N, Aoshima I, Matsuda Y, Nakayama T, Chiba R, Fujinuki T, Iwata K, Lu Q, Usuki T, Sakane F, Ishikawa T. Diacylglycerol kinase δ functions as a proliferation suppressor in pancreatic β-cells. FASEB J 2021; 35:e21420. [PMID: 33774855 DOI: 10.1096/fj.202001279rr] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 01/19/2021] [Accepted: 01/21/2021] [Indexed: 11/11/2022]
Abstract
Although an aberrant reduction in pancreatic β-cell mass contributes to the pathogenesis of diabetes, the mechanism underlying the regulation of β-cell mass is poorly understood. Here, we show that diacylglycerol kinase δ (DGKδ) is a key enzyme in the regulation of β-cell mass. DGKδ expression was detected in the nucleus of β-cells. We developed β-cell-specific DGKδ knockout (βDGKδ KO) mice, which showed lower blood glucose, higher plasma insulin levels, and better glucose tolerance compared to control mice. Moreover, an increased number of small islets and Ki-67-positive islet cells, as well as elevated cyclin B1 expression in the islets, were detected in the pancreas of βDGKδ KO mice. DGKδ knockdown in the β-cell line MIN6 induced significant increases in bromodeoxyuridine (BrdU) incorporation and cyclin B1 expression. Finally, we confirmed that streptozotocin-induced hyperglycemia and β-cell loss were alleviated in βDGKδ KO mice. Thus, suppressing the expression or enzymatic activity of DGKδ that functions as a suppressor of β-cell proliferation could be a novel therapeutic approach to increase β-cell mass for the treatment of diabetes.
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Affiliation(s)
- Taiji Sato
- Department of Pharmacology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Chihiro Ishiwatari
- Department of Pharmacology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Yukiko K Kaneko
- Department of Pharmacology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Yoko Ishikawa
- Department of Pharmacology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Yuki Kimura
- Department of Pharmacology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Naoya Watanabe
- Department of Pharmacology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Ikumi Aoshima
- Department of Pharmacology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Yukari Matsuda
- Department of Pharmacology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Takahiro Nakayama
- Department of Pharmacology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Rina Chiba
- Department of Pharmacology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Takahiro Fujinuki
- Department of Pharmacology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Kai Iwata
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, Japan
| | - Qiang Lu
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, Japan
| | - Takako Usuki
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, Japan
| | - Fumio Sakane
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, Japan
| | - Tomohisa Ishikawa
- Department of Pharmacology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
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10
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Sphingomyelin synthase-related protein generates diacylglycerol via the hydrolysis of glycerophospholipids in the absence of ceramide. J Biol Chem 2021; 296:100454. [PMID: 33621517 PMCID: PMC7988496 DOI: 10.1016/j.jbc.2021.100454] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 02/16/2021] [Accepted: 02/19/2021] [Indexed: 01/20/2023] Open
Abstract
Diacylglycerol (DG) is a well-established lipid second messenger. Sphingomyelin synthase (SMS)-related protein (SMSr) produces DG and ceramide phosphoethanolamine (CPE) by the transfer of phosphoethanolamine from phosphatidylethanolamine (PE) to ceramide. We previously reported that human SMSr overexpressed in COS-7 cells significantly increased DG levels, particularly saturated and/or monounsaturated fatty acid-containing DG molecular species, and provided DG to DG kinase (DGK) δ, which regulates various pathophysiological events, including epidermal growth factor-dependent cell proliferation, type 2 diabetes, and obsessive-compulsive disorder. However, mammalian SMSr puzzlingly produces only trace amounts of CPE/DG. To clarify this discrepancy, we highly purified SMSr and examined its activities other than CPE synthase. Intriguingly, purified SMSr showed a DG-generating activity via hydrolysis of PE, phosphatidic acid (PA), phosphatidylinositol (PI), and phosphatidylcholine (PC) in the absence of ceramide. DG generation through the PA phosphatase (PAP) activity of SMSr was approximately 300-fold higher than that with PE and ceramide. SMSr hydrolyzed PI ten times stronger than PI(4,5)bisphosphate (PI(4,5)P2). The PAP and PC-phospholipase C (PLC) activities of SMSr were inhibited by propranolol, a PAP inhibitor, and by D609, an SMS/PC-PLC inhibitor. Moreover, SMSr showed substrate selectivity for saturated and/or monounsaturated fatty acid-containing PA molecular species, but not arachidonic-acid-containing PA, which is exclusively generated in the PI(4,5)P2 cycle. We confirmed that SMSr expressed in COS-7 cells showed PAP and PI-PLC activities. Taken together, our study indicated that SMSr possesses previously unrecognized enzyme activities, PAP and PI/PE/PC-PLC, and constitutes a novel DG/PA signaling pathway together with DGKδ, which is independent of the PI(4,5)P2 cycle.
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Shu Y, Hassan F, Coppola V, Baskin KK, Han X, Mehta NK, Ostrowski MC, Mehta KD. Hepatocyte-specific PKCβ deficiency protects against high-fat diet-induced nonalcoholic hepatic steatosis. Mol Metab 2021; 44:101133. [PMID: 33271332 PMCID: PMC7785956 DOI: 10.1016/j.molmet.2020.101133] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 11/24/2020] [Accepted: 11/27/2020] [Indexed: 11/07/2022] Open
Abstract
OBJECTIVE Nonalcoholic hepatic steatosis, also known as fatty liver, is a uniform response of the liver to hyperlipidic-hypercaloric diet intake. However, the post-ingestive signals and mechanistic processes driving hepatic steatosis are not well understood. Emerging data demonstrate that protein kinase C beta (PKCβ), a lipid-sensitive kinase, plays a critical role in energy metabolism and adaptation to environmental and nutritional stimuli. Despite its powerful effect on glucose and lipid metabolism, knowledge of the physiological roles of hepatic PKCβ in energy homeostasis is limited. METHODS The floxed-PKCβ and hepatocyte-specific PKCβ-deficient mouse models were generated to study the in vivo role of hepatocyte PKCβ on diet-induced hepatic steatosis, lipid metabolism, and mitochondrial function. RESULTS We report that hepatocyte-specific PKCβ deficiency protects mice from development of hepatic steatosis induced by high-fat diet, without affecting body weight gain. This protection is associated with attenuation of SREBP-1c transactivation and improved hepatic mitochondrial respiratory chain. Lipidomic analysis identified significant increases in the critical mitochondrial inner membrane lipid, cardiolipin, in PKCβ-deficient livers compared to control. Moreover, hepatocyte PKCβ deficiency had no significant effect on either hepatic or whole-body insulin sensitivity supporting dissociation between hepatic steatosis and insulin resistance. CONCLUSIONS The above data indicate that hepatocyte PKCβ is a key focus of dietary lipid perception and is essential for efficient storage of dietary lipids in liver largely through coordinating energy utilization and lipogenesis during post-prandial period. These results highlight the importance of hepatic PKCβ as a drug target for obesity-associated nonalcoholic hepatic steatosis.
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Affiliation(s)
- Yaoling Shu
- Department of Biological Chemistry and Pharmacology, Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Faizule Hassan
- Department of Biological Chemistry and Pharmacology, Ohio State University Wexner Medical Center, Columbus, OH, USA
| | | | - Kedryn K Baskin
- Physiology and Cell Biology, Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Xianlin Han
- Department of Medicine, UT Health, San Antonio, TX, USA
| | | | - Michael C Ostrowski
- Department of Biochemistry and Molecular Biology, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, USA
| | - Kamal D Mehta
- Department of Biological Chemistry and Pharmacology, Ohio State University Wexner Medical Center, Columbus, OH, USA.
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Moin ASM, Al-Qaissi A, Sathyapalan T, Atkin SL, Butler AE. Platelet Protein-Related Abnormalities in Response to Acute Hypoglycemia in Type 2 Diabetes. Front Endocrinol (Lausanne) 2021; 12:651009. [PMID: 33859620 PMCID: PMC8043308 DOI: 10.3389/fendo.2021.651009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 03/16/2021] [Indexed: 12/17/2022] Open
Abstract
INTRODUCTION Patients with severe COVID-19 infections have coagulation abnormalities indicative of a hypercoagulable state, with thromboembolic complications and increased mortality. Platelets are recognized as mediators of inflammation, releasing proinflammatory and prothrombotic factors, and are hyperactivated in COVID-19 infected patients. Activated platelets have also been reported in type 2 diabetes (T2D) patients, putting these patients at higher risk for thromboembolic complications of COVID-19 infection. METHODS A case-control study of T2D (n=33) and control subjects (n=30) who underwent a hyperinsulinemic clamp to induce normoglycemia in T2D subjects: T2D: baseline glucose 7.5 ± 0.3mmol/l (135.1 ± 5.4mg/dl), reduced to 4.5 ± 0.07mmol/l (81 ± 1.2mg/dl) with 1-hour clamp; Controls: maintained at 5.1 ± 0.1mmol/l (91.9 ± 1.8mg/dl). Slow Off-rate Modified Aptamer (SOMA)-scan plasma protein measurement was used to determine a panel of platelet proteins. RESULTS Prothrombotic platelet proteins were elevated in T2D versus controls: platelet factor 4 (PF4, p<0.05); platelet glycoprotein VI (PGVI p<0.05); P-selectin (p<0.01) and plasminogen activator inhibitor I (PAI-1, p<0.01). In addition, the antithrombotic platelet-related proteins, plasmin (p<0.05) and heparin cofactor II (HCFII, p<0.05), were increased in T2D. Normalization of glucose in the T2D cohort had no effect on platelet protein levels. CONCLUSION T2D patients have platelet hyperactivation, placing them at higher risk for thromboembolic events. When infected with COVID-19, this risk may be compounded, and their propensity for a more severe COVID-19 disease course increased. CLINICAL TRIAL REGISTRATION https://clinicaltrials.gov/ct2/show/NCT03102801, identifier NCT03102801.
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Affiliation(s)
- Abu Saleh Md Moin
- Diabetes Research Center (DRC), Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation (QF), Doha, Qatar
| | - Ahmed Al-Qaissi
- Academic Endocrinology, Diabetes and Metabolism, Hull York Medical School, Hull, United Kingdom
- Academic Endocrinology, Leeds Medical School, Leeds, United Kingdom
| | - Thozhukat Sathyapalan
- Academic Endocrinology, Diabetes and Metabolism, Hull York Medical School, Hull, United Kingdom
| | - Stephen L. Atkin
- School of Postgraduate Studies and Research, Royal College of Surgeons in Ireland Bahrain, Adliya, Bahrain
| | - Alexandra E. Butler
- Diabetes Research Center (DRC), Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation (QF), Doha, Qatar
- *Correspondence: Alexandra E. Butler, ;
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Watt C, Sanchez-Rangel E, Hwang JJ. Glycemic Variability and CNS Inflammation: Reviewing the Connection. Nutrients 2020; 12:nu12123906. [PMID: 33371247 PMCID: PMC7766608 DOI: 10.3390/nu12123906] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 12/11/2020] [Accepted: 12/14/2020] [Indexed: 12/16/2022] Open
Abstract
Glucose is the primary energy source for the brain, and exposure to both high and low levels of glucose has been associated with numerous adverse central nervous system (CNS) outcomes. While a large body of work has highlighted the impact of hyperglycemia on peripheral and central measures of oxidative stress, cognitive deficits, and vascular complications in Type 1 and Type 2 diabetes, there is growing evidence that glycemic variability significantly drives increased oxidative stress, leading to neuroinflammation and cognitive dysfunction. In this review, the latest data on the impact of glycemic variability on brain function and neuroinflammation will be presented. Because high levels of oxidative stress have been linked to dysfunction of the blood-brain barrier (BBB), special emphasis will be placed on studies investigating the impact of glycemic variability on endothelial and vascular inflammation. The latest clinical and preclinical/in vitro data will be reviewed, and clinical/therapeutic implications will be discussed.
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Beyond Lipid Signaling: Pleiotropic Effects of Diacylglycerol Kinases in Cellular Signaling. Int J Mol Sci 2020; 21:ijms21186861. [PMID: 32962151 PMCID: PMC7554708 DOI: 10.3390/ijms21186861] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/11/2020] [Accepted: 09/16/2020] [Indexed: 12/13/2022] Open
Abstract
The diacylglycerol kinase family, which can attenuate diacylglycerol signaling and activate phosphatidic acid signaling, regulates various signaling transductions in the mammalian cells. Studies on the regulation of diacylglycerol and phosphatidic acid levels by various enzymes, the identification and characterization of various diacylglycerol and phosphatidic acid-regulated proteins, and the overlap of different diacylglycerol and phosphatidic acid metabolic and signaling processes have revealed the complex and non-redundant roles of diacylglycerol kinases in regulating multiple biochemical and biological networks. In this review article, we summarized recent progress in the complex and non-redundant roles of diacylglycerol kinases, which is expected to aid in restoring dysregulated biochemical and biological networks in various pathological conditions at the bed side.
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New Era of Diacylglycerol Kinase, Phosphatidic Acid and Phosphatidic Acid-Binding Protein. Int J Mol Sci 2020; 21:ijms21186794. [PMID: 32947951 PMCID: PMC7555651 DOI: 10.3390/ijms21186794] [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: 08/26/2020] [Revised: 09/11/2020] [Accepted: 09/14/2020] [Indexed: 12/12/2022] Open
Abstract
Diacylglycerol kinase (DGK) phosphorylates diacylglycerol (DG) to generate phosphatidic acid (PA). Mammalian DGK consists of ten isozymes (α–κ) and governs a wide range of physiological and pathological events, including immune responses, neuronal networking, bipolar disorder, obsessive-compulsive disorder, fragile X syndrome, cancer, and type 2 diabetes. DG and PA comprise diverse molecular species that have different acyl chains at the sn-1 and sn-2 positions. Because the DGK activity is essential for phosphatidylinositol turnover, which exclusively produces 1-stearoyl-2-arachidonoyl-DG, it has been generally thought that all DGK isozymes utilize the DG species derived from the turnover. However, it was recently revealed that DGK isozymes, except for DGKε, phosphorylate diverse DG species, which are not derived from phosphatidylinositol turnover. In addition, various PA-binding proteins (PABPs), which have different selectivities for PA species, were recently found. These results suggest that DGK–PA–PABP axes can potentially construct a large and complex signaling network and play physiologically and pathologically important roles in addition to DGK-dependent attenuation of DG–DG-binding protein axes. For example, 1-stearoyl-2-docosahexaenoyl-PA produced by DGKδ interacts with and activates Praja-1, the E3 ubiquitin ligase acting on the serotonin transporter, which is a target of drugs for obsessive-compulsive and major depressive disorders, in the brain. This article reviews recent research progress on PA species produced by DGK isozymes, the selective binding of PABPs to PA species and a phosphatidylinositol turnover-independent DG supply pathway.
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16
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Birkeland ES, Koch LM, Dechant R. Another Consequence of the Warburg Effect? Metabolic Regulation of Na +/H + Exchangers May Link Aerobic Glycolysis to Cell Growth. Front Oncol 2020; 10:1561. [PMID: 32974190 PMCID: PMC7462004 DOI: 10.3389/fonc.2020.01561] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 07/20/2020] [Indexed: 12/13/2022] Open
Abstract
To adjust cell growth and proliferation to changing environmental conditions or developmental requirements, cells have evolved a remarkable network of signaling cascades that integrates cues from cellular metabolism, growth factor availability and a large variety of stresses. In these networks, cellular information flow is mostly mediated by posttranslational modifications, most notably phosphorylation, or signaling molecules such as GTPases. Yet, a large body of evidence also implicates cytosolic pH (pHc) as a highly conserved cellular signal driving cell growth and proliferation, suggesting that pH-dependent protonation of specific proteins also regulates cellular signaling. In mammalian cells, pHc is regulated by growth factor derived signals and responds to metabolic cues in response to glucose stimulation. Importantly, high pHc has also been identified as a hall mark of cancer, but mechanisms of pH regulation in cancer are only poorly understood. Here, we discuss potential mechanisms of pH regulation with emphasis on metabolic signals regulating pHc by Na+/H+-exchangers. We hypothesize that elevated NHE activity and pHc in cancer are a direct consequence of the metabolic adaptations in tumor cells including enhanced aerobic glycolysis, generally referred to as the Warburg effect. This hypothesis not only provides an explanation for the growth advantage conferred by a switch to aerobic glycolysis beyond providing precursors for accumulation of biomass, but also suggests that treatments targeting pH regulation as a potential anti-cancer therapy may effectively target the result of altered tumor cell metabolism.
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Affiliation(s)
- Eivind Salmorin Birkeland
- Institute of Biochemistry, Department of Biology, ETH Zürich, Zurich, Switzerland.,Life Science Zurich, Ph.D. Program for Molecular Life Sciences, Zurich, Switzerland
| | - Lisa Maria Koch
- Institute of Biochemistry, Department of Biology, ETH Zürich, Zurich, Switzerland.,Life Science Zurich, Ph.D. Program for Molecular Life Sciences, Zurich, Switzerland
| | - Reinhard Dechant
- Institute of Biochemistry, Department of Biology, ETH Zürich, Zurich, Switzerland
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17
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Liu CS, Schmezer P, Popanda O. Diacylglycerol Kinase Alpha in Radiation-Induced Fibrosis: Potential as a Predictive Marker or Therapeutic Target. Front Oncol 2020; 10:737. [PMID: 32477950 PMCID: PMC7235333 DOI: 10.3389/fonc.2020.00737] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 04/17/2020] [Indexed: 12/14/2022] Open
Abstract
Radiotherapy is an efficient tool in cancer treatment, but it brings along the risk of side effects such as fibrosis in the irradiated healthy tissue thus limiting tumor control and impairing quality of life of cancer survivors. Knowledge on radiation-related fibrosis risk and therapeutic options is still limited and requires further research. Recent studies demonstrated that epigenetic regulation of diacylglycerol kinase alpha (DGKA) is associated with radiation-induced fibrosis. However, the specific mechanisms are still unknown. In this review, we scrutinized the role of DGKA in the radiation response and in further cellular functions to show the potential of DGKA as a predictive marker or a novel target in fibrosis treatment. DGKA was reported to participate in immune response, lipid signaling, exosome production, and migration as well as cell proliferation, all processes which are suggested to be critical steps in fibrogenesis. Most of these functions are based on the conversion of diacylglycerol (DAG) to phosphatidic acid (PA) at plasma membranes, but DGKA might have also other, yet not well-known functions in the nucleus. Current evidence summarized here underlines that DGKA activation may play a central role in fibrosis formation post-irradiation and shows a potential of direct DGKA inhibitors or epigenetic modulators to attenuate pro-fibrotic reactions, thus providing novel therapeutic choices.
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Affiliation(s)
- Chun-Shan Liu
- Division of Cancer Epigenomics, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Peter Schmezer
- Division of Cancer Epigenomics, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Odilia Popanda
- Division of Cancer Epigenomics, German Cancer Research Center (DKFZ), Heidelberg, Germany
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18
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Green HLH, Brewer AC. Dysregulation of 2-oxoglutarate-dependent dioxygenases by hyperglycaemia: does this link diabetes and vascular disease? Clin Epigenetics 2020; 12:59. [PMID: 32345373 PMCID: PMC7189706 DOI: 10.1186/s13148-020-00848-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 04/08/2020] [Indexed: 02/06/2023] Open
Abstract
The clinical, social and economic burden of cardiovascular disease (CVD) associated with diabetes underscores an urgency for understanding the disease aetiology. Evidence suggests that the hyperglycaemia associated with diabetes is, of itself, causal in the development of endothelial dysfunction (ED) which is recognised to be the critical determinant in the development of CVD. It is further recognised that epigenetic modifications associated with changes in gene expression are causal in both the initiation of ED and the progression to CVD. Understanding whether and how hyperglycaemia induces epigenetic modifications therefore seems crucial in the development of preventative treatments. A mechanistic link between energy metabolism and epigenetic regulation is increasingly becoming explored as key energy metabolites typically serve as substrates or co-factors for epigenetic modifying enzymes. Intriguing examples are the ten-eleven translocation and Jumonji C proteins which facilitate the demethylation of DNA and histones respectively. These are members of the 2-oxoglutarate-dependent dioxygenase superfamily which require the tricarboxylic acid metabolite, α-ketoglutarate and molecular oxygen (O2) as substrates and Fe (II) as a co-factor. An understanding of precisely how the biochemical effects of high glucose exposure impact upon cellular metabolism, O2 availability and cellular redox in endothelial cells (ECs) may therefore elucidate (in part) the mechanistic link between hyperglycaemia and epigenetic modifications causal in ED and CVD. It would also provide significant proof of concept that dysregulation of the epigenetic landscape may be causal rather than consequential in the development of pathology.
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Affiliation(s)
- Hannah L H Green
- School of Cardiovascular Medicine & Sciences, King's College London British Heart Foundation Centre of Research Excellence, London, UK
| | - Alison C Brewer
- School of Cardiovascular Medicine & Sciences, King's College London British Heart Foundation Centre of Research Excellence, London, UK.
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Murakami C, Hoshino F, Sakai H, Hayashi Y, Yamashita A, Sakane F. Diacylglycerol kinase δ and sphingomyelin synthase-related protein functionally interact via their sterile α motif domains. J Biol Chem 2020; 295:2932-2947. [PMID: 31980461 DOI: 10.1074/jbc.ra119.012369] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/23/2020] [Indexed: 12/27/2022] Open
Abstract
The δ isozyme of diacylglycerol kinase (DGKδ) plays critical roles in lipid signaling by converting diacylglycerol (DG) to phosphatidic acid (PA). We previously demonstrated that DGKδ preferably phosphorylates palmitic acid (16:0)- and/or palmitoleic acid (16:1)-containing DG molecular species, but not arachidonic acid (20:4)-containing DG species, which are recognized as DGK substrates derived from phosphatidylinositol turnover, in high glucose-stimulated myoblasts. However, little is known about the origin of these DG molecular species. DGKδ and two DG-generating enzymes, sphingomyelin synthase (SMS) 1 and SMS-related protein (SMSr), contain a sterile α motif domain (SAMD). In this study, we found that SMSr-SAMD, but not SMS1-SAMD, co-immunoprecipitates with DGKδ-SAMD. Full-length DGKδ co-precipitated with full-length SMSr more strongly than with SMS1. However, SAMD-deleted variants of SMSr and DGKδ interacted only weakly with full-length DGKδ and SMSr, respectively. These results strongly suggested that DGKδ interacts with SMSr through their respective SAMDs. To determine the functional outcomes of the relationship between DGKδ and SMSr, we used LC-MS/MS to investigate whether overexpression of DGKδ and/or SMSr in COS-7 cells alters the levels of PA species. We found that SMSr overexpression significantly enhances the production of 16:0- or 16:1-containing PA species such as 14:0/16:0-, 16:0/16:0-, 16:0/18:1-, and/or 16:1/18:1-PA in DGKδ-overexpressing COS-7 cells. Moreover, SMSr enhanced DGKδ activity via their SAMDs in vitro Taken together, these results strongly suggest that SMSr is a candidate DG-providing enzyme upstream of DGKδ and that the two enzymes represent a new pathway independent of phosphatidylinositol turnover.
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Affiliation(s)
- Chiaki Murakami
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba 263-8522, Japan
| | - Fumi Hoshino
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba 263-8522, Japan
| | - Hiromichi Sakai
- Department of Biosignaling and Radioisotope Experiment, Interdisciplinary Center for Science Research, Organization for Research and Academic Information, Shimane University, Izumo 693-8501, Japan
| | - Yasuhiro Hayashi
- Faculty of Pharma Sciences, Teikyo University, Kaga 2-11-1, Itabashi-ku, Tokyo 173-8605, Japan
| | - Atsushi Yamashita
- Faculty of Pharma Sciences, Teikyo University, Kaga 2-11-1, Itabashi-ku, Tokyo 173-8605, Japan
| | - Fumio Sakane
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba 263-8522, Japan.
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Massart J, Zierath JR. Role of Diacylglycerol Kinases in Glucose and Energy Homeostasis. Trends Endocrinol Metab 2019; 30:603-617. [PMID: 31331711 DOI: 10.1016/j.tem.2019.06.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 06/20/2019] [Accepted: 06/21/2019] [Indexed: 01/22/2023]
Abstract
Diacylglycerol kinases (DGKs) catalyze a reaction that converts diacylglycerol (DAG) to phosphatidic acid (PA). DAG and PA act as intermediates of de novo lipid synthesis, cellular membrane constituents, and signaling molecules. DGK isoforms regulate a variety of intracellular processes by terminating DAG signaling and activating PA-mediated pathways. The ten DGK isoforms are unique, not only structurally, but also in tissue-specific expression profiles, subcellular localization, regulatory mechanisms, and DAG preferences, suggesting isoform-specific functions. DAG accumulation has been associated with insulin resistance; however, this concept is challenged by opposing roles of DGK isoforms in the development of type 2 diabetes and obesity despite elevated DAG levels. This review focuses on the tissue- and isoform-specific role of DGK in glucose and energy homeostasis.
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Affiliation(s)
- Julie Massart
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Juleen R Zierath
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; The Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark.
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Hoshino F, Murakami C, Sakai H, Satoh M, Sakane F. Creatine kinase muscle type specifically interacts with saturated fatty acid- and/or monounsaturated fatty acid-containing phosphatidic acids. Biochem Biophys Res Commun 2019; 513:1035-1040. [DOI: 10.1016/j.bbrc.2019.04.097] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 04/05/2019] [Accepted: 04/13/2019] [Indexed: 01/03/2023]
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Iwata K, Sakai H, Takahashi D, Sakane F. Myristic acid specifically stabilizes diacylglycerol kinase δ protein in C2C12 skeletal muscle cells. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1864:1031-1038. [PMID: 30980919 DOI: 10.1016/j.bbalip.2019.04.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 12/20/2018] [Accepted: 01/06/2019] [Indexed: 02/01/2023]
Abstract
Decreased levels of the δ isozyme of diacylglycerol kinase (DGK) in skeletal muscle attenuate glucose uptake and, consequently, are critical for the pathogenesis of type 2 diabetes. We recently found that free myristic acid (14:0), but not free palmitic acid (16:0), increased the DGKδ protein levels and enhanced glucose uptake in C2C12 myotube cells. However, it has been unclear how myristic acid regulates the level of DGKδ2 protein. In the present study, we characterized the myristic acid-dependent increase of DGKδ protein. A cycloheximide chase assay demonstrated that myristic acid, but not palmitic acid, markedly stabilized DGKδ protein. Moreover, other DGK isozymes, DGKη and ζ, as well as glucose uptake-related proteins, such as protein kinase C (PKC) α, PKCζ, Akt and glycogen synthase kinase 3β, failed to be stabilized by myristic acid. Furthermore, DGKδ was not stabilized in cultured hepatocellular carcinoma cells, pancreas carcinoma cells or neuroblastoma cells, and only a moderate stabilizing effect was observed in embryonic kidney cells. A proteasome inhibitor and a lysosome inhibitor, MG132 and chloroquine, respectively, partly inhibited DGKδ degradation, suggesting that myristic acid prevents, at least in part, the degradation of DGKδ by the ubiquitin-proteasome system and the autophagy-lysosome pathway. Overall, these results strongly suggest that myristic acid attenuates DGKδ protein degradation in skeletal muscle cells and that this attenuation is fatty acid-, protein- and cell line-specific. These new findings provide novel insights into the molecular mechanisms of the pathogenesis of type 2 diabetes mellitus.
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Affiliation(s)
- Kai Iwata
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba 263-8522, Japan
| | - Hiromichi Sakai
- Department of Biosignaling and Radioisotope Experiment, Interdisciplinary Center for Science Research, Organization for Research and Academic Information, Shimane University, Izumo 693-8501, Japan
| | - Daisuke Takahashi
- Department of Pharmaceutical Health Care and Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Fumio Sakane
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba 263-8522, Japan.
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Sakai H, Murakami C, Matsumoto KI, Urano T, Sakane F. Diacylglycerol kinase δ controls down-regulation of cyclin D1 for C2C12 myogenic differentiation. Biochimie 2018; 151:45-53. [PMID: 29859210 DOI: 10.1016/j.biochi.2018.05.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Accepted: 05/28/2018] [Indexed: 12/25/2022]
Abstract
Diacylglycerol kinase (DGK) is a lipid-metabolizing enzyme that phosphorylates diacylglycerol (DG) to produce phosphatidic acid (PA). DGKδ is highly expressed in the skeletal muscle, and a decrease in DGKδ expression increases the severity of type 2 diabetes. However, the role of DGKδ in myogenic differentiation is still unknown. The present study demonstrated that DGKδ expression was down-regulated in the early stage of C2C12 myogenic differentiation almost concurrently with a decrease in cyclin D1 expression. The knockdown of DGKδ by DGKδ-specific siRNAs significantly increased the levels of cyclin D1 expression at 48 h after C2C12 myogenic differentiation. In contrast, at the same time, the knockdown of DGKδ decreased the levels of myogenin expression and the number of myosin heavy chain (MHC)-positive cells. These results indicate that DGKδ regulates the early differentiation of C2C12 myoblasts via controlling the down-regulation of cyclin D1 expression. Moreover, the suppression of DGKδ expression increased the phosphorylation levels of conventional and novel protein kinase Cs (cnPKCs). Furthermore, DGKδ suppression increased the levels of cyclin D1 and phospho-cnPKCs even at the first 24 h of myogenic differentiation. These results suggest that DGKδ controls the down-regulation of cyclin D1 expression by attenuating the PKC signaling pathway for C2C12 myogenic differentiation.
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Affiliation(s)
- Hiromichi Sakai
- Department of Biosignaling and Radioisotope Experiment, Interdisciplinary Center for Science Research, Organization for Research and Academic Information, Shimane University, Izumo, Japan.
| | - Chiaki Murakami
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, Japan
| | - Ken-Ichi Matsumoto
- Department of Biosignaling and Radioisotope Experiment, Interdisciplinary Center for Science Research, Organization for Research and Academic Information, Shimane University, Izumo, Japan
| | - Takeshi Urano
- Department of Biosignaling and Radioisotope Experiment, Interdisciplinary Center for Science Research, Organization for Research and Academic Information, Shimane University, Izumo, Japan; Department of Biochemistry, Shimane University School of Medicine, Izumo, Japan
| | - Fumio Sakane
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, Japan.
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Sakane F, Mizuno S, Takahashi D, Sakai H. Where do substrates of diacylglycerol kinases come from? Diacylglycerol kinases utilize diacylglycerol species supplied from phosphatidylinositol turnover-independent pathways. Adv Biol Regul 2018; 67:101-108. [PMID: 28918129 DOI: 10.1016/j.jbior.2017.09.003] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 09/08/2017] [Accepted: 09/08/2017] [Indexed: 06/07/2023]
Abstract
Diacylglycerol kinase (DGK) phosphorylates diacylglycerol (DG) to produce phosphatidic acid (PA). Mammalian DGK comprises ten isozymes (α-κ) and regulates a wide variety of physiological and pathological events, such as cancer, type II diabetes, neuronal disorders and immune responses. DG and PA consist of various molecular species that have different acyl chains at the sn-1 and sn-2 positions, and consequently, mammalian cells contain at least 50 structurally distinct DG/PA species. Because DGK is one of the components of phosphatidylinositol (PI) turnover, the generally accepted dogma is that all DGK isozymes utilize 18:0/20:4-DG derived from PI turnover. We recently established a specific liquid chromatography-mass spectrometry method to analyze which PA species were generated by DGK isozymes in a cell stimulation-dependent manner. Interestingly, we determined that DGKδ, which is closely related to the pathogenesis of type II diabetes, preferentially utilized 14:0/16:0-, 14:0/16:1-, 16:0/16:0-, 16:0/16:1-, 16:0/18:0- and 16:0/18:1-DG species (X:Y = the total number of carbon atoms: the total number of double bonds) supplied from the phosphatidylcholine-specific phospholipase C pathway, but not 18:0/20:4-DG, in high glucose-stimulated C2C12 myoblasts. Moreover, DGKα mainly consumed 14:0/16:0-, 16:0/18:1-, 18:0/18:1- and 18:1/18:1-DG species during cell proliferation in AKI melanoma cells. Furthermore, we found that 16:0/16:0-PA was specifically produced by DGKζ in Neuro-2a cells during retinoic acid- and serum starvation-induced neuronal differentiation. These results indicate that DGK isozymes utilize a variety of DG molecular species derived from PI turnover-independent pathways as substrates in different stimuli and cells. DGK isozymes phosphorylate various DG species to generate various PA species. It was revealed that the modes of activation of conventional and novel protein kinase isoforms by DG molecular species varied considerably. However, PA species-selective binding proteins have not been found to date. Therefore, we next attempted to identify PA species-selective binding proteins from the mouse brain and identified α-synuclein, which has causal links to Parkinson's disease. Intriguingly, we determined that among phospholipids, including several PA species (16:0/16:0-PA, 16:0/18:1-PA, 18:1/18:1-PA, 18:0/18:0-PA and 18:0/20:4-PA); 18:1/18:1-PA was the most strongly bound PA to α-synuclein. Moreover, 18:1/18:1-PA strongly enhanced secondary structural changes from the random coil form to the α-helix form and generated a multimeric and proteinase K-resistant α-synuclein protein. In contrast with the dogma described above, our recent studies strongly suggest that PI turnover-derived DG species and also various DG species derived from PI turnover-independent pathways are utilized by DGK isozymes. DG species supplied from distinct pathways may be utilized by DGK isozymes based on different stimuli present in different types of cells, and individual PA molecular species would have specific targets and exert their own physiological functions.
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Affiliation(s)
- Fumio Sakane
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, Japan.
| | - Satoru Mizuno
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, Japan
| | - Daisuke Takahashi
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, Japan
| | - Hiromichi Sakai
- Department of Biosignaling and Radioisotope Experiment, Interdisciplinary Center for Science Research, Organization for Research and Academic Information, Shimane University, Izumo, Japan
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Takato T, Iwata K, Murakami C, Wada Y, Sakane F. Chronic administration of myristic acid improves hyperglycaemia in the Nagoya-Shibata-Yasuda mouse model of congenital type 2 diabetes. Diabetologia 2017; 60:2076-2083. [PMID: 28707095 DOI: 10.1007/s00125-017-4366-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 06/06/2017] [Indexed: 12/18/2022]
Abstract
AIMS/HYPOTHESIS Previously, we demonstrated that myristic acid (14:0) increases levels of diacylglycerol kinase (DGK) δ, a key enzyme involved in type 2 diabetes exacerbation, and enhances glucose uptake in C2C12 myotube cells. Moreover, results from a population-based cohort study suggest that consumption of high-fat dairy products, which contain high amounts of myristic acid, is associated with a lower risk of developing type 2 diabetes. Taken together, we hypothesised that intake of myristic acid reduces type 2 diabetes risk in vivo. The aim of this study was to examine the glucose-lowering effect of myristic acid in Nagoya-Shibata-Yasuda (NSY) mice, a spontaneous model for studying obesity-related type 2 diabetes. METHODS Male NSY mice were orally administered vehicle (n = 9), 300 mg/kg of myristic acid (n = 14) or 300 mg/kg of palmitic acid (16:0) (n = 9) every other day from 4 weeks of age. Glucose and insulin tolerance tests were performed at weeks 18, 24 and 30, and weeks 20 and 26, respectively. DGKδ levels were measured in skeletal muscle from 32-36-week-old NSY mice via western blot. RESULTS Chronic oral administration of myristic acid ameliorated glucose tolerance (24-28% decrease in blood glucose levels during glucose tolerance tests) and reduced insulin-responsive blood glucose levels (~20% decrease) in male NSY mice compared with vehicle and palmitic acid groups at 24-30 weeks of age (the age at which the severity of type 2 diabetes is exacerbated in NSY mice). Myristic acid also attenuated the increase in body weight seen in NSY mice. Furthermore, the fatty acid increased DGKδ levels (~1.6-fold) in skeletal muscle of NSY mice. CONCLUSIONS/INTERPRETATION These results suggest that the chronic oral administration of myristic acid improves hyperglycaemia by decreasing insulin-responsive glucose levels and reducing body weight, and that the fatty acid accounts for the diabetes protective properties of high-fat dairy products. Myristic acid is a potential candidate for the prevention and treatment of type 2 diabetes mellitus and its related diseases.
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Affiliation(s)
- Tamae Takato
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Kai Iwata
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Chiaki Murakami
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Yuko Wada
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Fumio Sakane
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan.
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Mannerås-Holm L, Schönke M, Brozinick JT, Vetterli L, Bui HH, Sanders P, Nascimento EBM, Björnholm M, Chibalin AV, Zierath JR. Diacylglycerol kinase ε deficiency preserves glucose tolerance and modulates lipid metabolism in obese mice. J Lipid Res 2017; 58:907-915. [PMID: 28246337 DOI: 10.1194/jlr.m074443] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 02/13/2017] [Indexed: 12/19/2022] Open
Abstract
Diacylglycerol kinases (DGKs) catalyze the phosphorylation and conversion of diacylglycerol (DAG) into phosphatidic acid. DGK isozymes have unique primary structures, expression patterns, subcellular localizations, regulatory mechanisms, and DAG preferences. DGKε has a hydrophobic segment that promotes its attachment to membranes and shows substrate specificity for DAG with an arachidonoyl acyl chain in the sn-2 position of the substrate. We determined the role of DGKε in the regulation of energy and glucose homeostasis in relation to diet-induced insulin resistance and obesity using DGKε-KO and wild-type mice. Lipidomic analysis revealed elevated unsaturated and saturated DAG species in skeletal muscle of DGKε KO mice, which was paradoxically associated with increased glucose tolerance. Although skeletal muscle insulin sensitivity was unaltered, whole-body respiratory exchange ratio was reduced, and abundance of mitochondrial markers was increased, indicating a greater reliance on fat oxidation and intracellular lipid metabolism in DGKε KO mice. Thus, the increased intracellular lipids in skeletal muscle from DGKε KO mice may undergo rapid turnover because of increased mitochondrial function and lipid oxidation, rather than storage, which in turn may preserve insulin sensitivity. In conclusion, DGKε plays a role in glucose and energy homeostasis by modulating lipid metabolism in skeletal muscle.
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Affiliation(s)
- Louise Mannerås-Holm
- Section of Integrative Physiology, Department of Molecular Medicine and Surgery and Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Milena Schönke
- Section of Integrative Physiology, Department of Molecular Medicine and Surgery and Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | | | - Laurène Vetterli
- Section of Integrative Physiology, Department of Molecular Medicine and Surgery and Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Hai-Hoang Bui
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN
| | - Philip Sanders
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN
| | - Emmani B M Nascimento
- Section of Integrative Physiology, Department of Molecular Medicine and Surgery and Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Marie Björnholm
- Section of Integrative Physiology, Department of Molecular Medicine and Surgery and Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Alexander V Chibalin
- Section of Integrative Physiology, Department of Molecular Medicine and Surgery and Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Juleen R Zierath
- Section of Integrative Physiology, Department of Molecular Medicine and Surgery and Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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Geng X, Li F, Yip J, Peng C, Elmadhoun O, Shen J, Ji X, Ding Y. Neuroprotection by Chlorpromazine and Promethazine in Severe Transient and Permanent Ischemic Stroke. Mol Neurobiol 2016; 54:8140-8150. [DOI: 10.1007/s12035-016-0280-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 10/31/2016] [Indexed: 12/20/2022]
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Behavioral and pharmacological phenotypes of brain-specific diacylglycerol kinase δ-knockout mice. Brain Res 2016; 1648:193-201. [DOI: 10.1016/j.brainres.2016.07.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 07/06/2016] [Accepted: 07/12/2016] [Indexed: 12/31/2022]
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Kamiya Y, Mizuno S, Komenoi S, Sakai H, Sakane F. Activation of conventional and novel protein kinase C isozymes by different diacylglycerol molecular species. Biochem Biophys Rep 2016; 7:361-366. [PMID: 28955926 PMCID: PMC5613651 DOI: 10.1016/j.bbrep.2016.07.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 07/13/2016] [Accepted: 07/15/2016] [Indexed: 12/25/2022] Open
Abstract
A variety of diacylglycerol (DG) molecular species are produced in stimulated cells. Conventional (α, βII and γ) and novel (δ, ε, η and θ) protein kinase C (PKC) isoforms are known to be activated by DG. However, a comprehensive analysis has not been performed. In this study, we analyzed activation of the PKC isozymes in the presence of 2–2000 mmol% 16:0/16:0-, 16:0/18:1-, 18:1/18:1-, 18:0/20:4- or 18:0/22:6-DG species. PKCα activity was strongly increased by DG and exhibited less of a preference for 18:0/22:6-DG at 2 mmol%. PKCβII activity was moderately increased by DG and did not have significant preference for DG species. PKCγ activity was moderately increased by DG and exhibited a moderate preference for 18:0/22:6-DG at 2 mmol%. PKCδ activity was moderately increased by DG and exhibited a preference for 18:0/22:6-DG at 20 and 200 mmol%. PKCε activity moderately increased by DG and showed a moderate preference for 18:0/22:6-DG at 2000 mmol%. PKCη was not markedly activated by DG. PKCθ activity was the most strongly increased by DG and exhibited a preference for 18:0/22:6-DG at 2 and 20 mmol% DG. These results indicate that conventional and novel PKCs have different sensitivities and dependences on DG and a distinct preference for shorter and saturated fatty acid-containing and longer and polyunsaturated fatty acid-containing DG species, respectively. This differential regulation would be important for their physiological functions. We comprehensively analyzed activation of c/nPKC isozymes by different DG species. c/nPKCs have different sensitivities and dependences on DG. c/nPKCs have a distinct preference for different fatty acid-containing DG species. This differential regulation would be important for PKCs' physiological functions.
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Affiliation(s)
- Yuuna Kamiya
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Satoru Mizuno
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Suguru Komenoi
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Hiromichi Sakai
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Fumio Sakane
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
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Distinct 1-monoacylglycerol and 2-monoacylglycerol kinase activities of diacylglycerol kinase isozymes. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1864:1170-1176. [PMID: 27346717 DOI: 10.1016/j.bbapap.2016.06.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 06/15/2016] [Accepted: 06/22/2016] [Indexed: 02/02/2023]
Abstract
Diacylglycerol kinase (DGK) consists of ten isozymes and is involved in a wide variety of patho-physiological events. However, the enzymological properties of DGKs have not been fully understood. In this study, we performed a comprehensive analysis on the 1-monoacylglycerol kinase (MGK) and 2-MGK activities of ten DGK isozymes. We revealed that type I (α, β and γ), type II (δ, η and κ) and type III (ε) DGKs have 7.9-19.2% 2-MGK activity compared to their DGK activities, whereas their 1-MGK activities were <3.0%. Both the 1-MGK and 2-MGK activities of the type IV DGKs (ζ and ι) were <1% relative to their DGK activities. Intriguingly, type V DGKθ has approximately 6% 1-MGK activity and <2% 2-MGK activity compared to its DGK activity. Purified DGKθ exhibited the same results, indicating that its 1-MGK activity is intrinsic. Therefore, DGK isozymes are categorized into three types with respect to their 1-MGK and 2-MGK activities: those having (1) 2-MGK activity relatively stronger than their 1-MGK activity (types I-III), (2) only negligible 1-MGK and 2-MGK activities (type IV), and (3) 1-MGK activity stronger than its 2-MGK activity (type V). The 1-MGK activity of DGKθ and the 2-MGK activity of DGKα were stronger than those of the acylglycerol kinase reported as 1-MGK and 2-MGK to date. The presence or absence of 1-MGK and 2-MGK activities may be essential to the patho-physiological functions of each DGK isozyme.
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Wada Y, Sakiyama S, Sakai H, Sakane F. Myristic Acid Enhances Diacylglycerol Kinase δ-Dependent Glucose Uptake in Myotubes. Lipids 2016; 51:897-903. [PMID: 27206979 DOI: 10.1007/s11745-016-4162-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 05/05/2016] [Indexed: 11/28/2022]
Abstract
Decreased expression of diacylglycerol kinase (DGK) δ in skeletal muscles attenuates glucose uptake and is closely related to the pathogenesis of type 2 diabetes. Therefore, up-regulation of DGKδ expression is thought to protect and improve glucose homoeostasis in type 2 diabetes. We recently determined that myristic acid (14:0), but not palmitic (16:0) or stearic (18:0) acid, significantly increased DGKδ2 protein expression in mouse C2C12 myotubes. In the current study, we analyzed whether myristic acid indeed enhances glucose uptake in C2C12 myotubes. We observed that myristic acid caused ~1.4-fold increase in insulin-independent glucose uptake. However, palmitic and stearic acids failed to enhance glucose uptake. DGKδ-specific siRNA decreased myristic acid-dependent increase of glucose uptake. Moreover, overexpression of DGKδ2 enhanced glucose uptake in C2C12 cells in the absence of myristic acid treatment. Taken together, these results strongly suggest that myristic acid enhances basal glucose uptake in myotubes in a DGKδ2 expression-dependent manner.
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Affiliation(s)
- Yuko Wada
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Shizuka Sakiyama
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Hiromichi Sakai
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Fumio Sakane
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan.
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Kume A, Kawase K, Komenoi S, Usuki T, Takeshita E, Sakai H, Sakane F. The Pleckstrin Homology Domain of Diacylglycerol Kinase η Strongly and Selectively Binds to Phosphatidylinositol 4,5-Bisphosphate. J Biol Chem 2016; 291:8150-61. [PMID: 26887948 DOI: 10.1074/jbc.m115.648717] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Indexed: 11/06/2022] Open
Abstract
Type II diacylglycerol kinase (DGK) isozymes (δ, η, and κ) have a pleckstrin homology domain (PH) at their N termini. Here, we investigated the lipid binding properties of the PHs of type II DGK isozymes using protein-lipid overlay and liposome binding assays. The PH of DGKη showed the most pronounced binding activity to phosphatidylinositol (PI) 4,5-bisphosphate (PI(4,5)P2) among the various glycero- and sphingolipids including PI 3,4,5-trisphosphate, PI 3,4-bisphosphate, PI 3-phosphate, PI 4-phosphate, and PI 5-phosphate. Moreover, the PI(4,5)P2binding activity of the DGKη-PH was significantly stronger than that of other type II DGK isozymes. Notably, compared with the PH of phospholipase C (PLC) δ1, which is generally utilized as a cellular PI(4,5)P2- probe, the DGKη-PH is equal to or superior than the PLCδ1-PH in terms of affinity and selectivity for PI(4,5)P2 Furthermore, in COS-7 cells, GFP-fused wild-type DGKη1 and its PH partly translocated from the cytoplasm to the plasma membrane where the PLCδ1-PH was co-localized in response to hyperosmotic stress in an inositol 5-phosphatase-sensitive manner, whereas a PH deletion mutant did not. Moreover, K74A and R85A mutants of DGKη-PH, which lack the conserved basic amino acids thought to ligate PI(4,5)P2, were indeed unable to bind to PI(4,5)P2and co-localize with the PLCδ1-PH even in osmotically shocked cells. Overexpression of wild-type DGKη1 enhanced EGF-dependent phosphorylation of ERK, whereas either K74A or R85A mutant did not. Taken together, these results indicate that the DGKη-PH preferentially interacts with PI(4,5)P2and has crucial roles in regulating the subcellular localization and physiological function of DGKη. Moreover, the DGKη-PH could serve as an excellent cellular sensor for PI(4,5)P2.
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Affiliation(s)
- Aiko Kume
- From the Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Koki Kawase
- From the Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Suguru Komenoi
- From the Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Takako Usuki
- From the Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Ena Takeshita
- From the Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Hiromichi Sakai
- From the Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Fumio Sakane
- From the Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
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Jackson R, Brennan S, Fielding P, Sims MW, Challiss RAJ, Adlam D, Squire IB, Rainbow RD. Distinct and complementary roles for α and β isoenzymes of PKC in mediating vasoconstrictor responses to acutely elevated glucose. Br J Pharmacol 2016; 173:870-87. [PMID: 26660275 DOI: 10.1111/bph.13399] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 11/23/2015] [Accepted: 11/30/2015] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND AND PURPOSE We investigated the hypothesis that elevated glucose increases contractile responses in vascular smooth muscle and that this enhanced constriction occurs due to the glucose-induced PKC-dependent inhibition of voltage-gated potassium channels. EXPERIMENTAL APPROACH Patch-clamp electrophysiology in rat isolated mesenteric arterial myocytes was performed to investigate the glucose-induced inhibition of voltage-gated potassium (Kv ) current. To determine the effects of glucose in whole vessel, wire myography was performed in rat mesenteric, porcine coronary and human internal mammary arteries. KEY RESULTS Glucose-induced inhibition of Kv was PKC-dependent and could be pharmacologically dissected using PKC isoenzyme-specific inhibitors to reveal a PKCβ-dependent component of Kv inhibition dominating between 0 and 10 mM glucose with an additional PKCα-dependent component becoming evident at concentrations greater than 10 mM. These findings were supported using wire myography in all artery types used, where contractile responses to vessel depolarization and vasoconstrictors were enhanced by increasing bathing glucose concentration, again with evidence for distinct and complementary PKCα/PKCβ-mediated components. CONCLUSIONS AND IMPLICATIONS Our results provide compelling evidence that glucose-induced PKCα/PKCβ-mediated inhibition of Kv current in vascular smooth muscle causes an enhanced constrictor response. Inhibition of Kv current causes a significant depolarization of vascular myocytes leading to marked vasoconstriction. The PKC dependence of this enhanced constrictor response may present a potential therapeutic target for improving microvascular perfusion following percutaneous coronary intervention after myocardial infarction in hyperglycaemic patients.
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Affiliation(s)
- Robert Jackson
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, UK
| | - Sean Brennan
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, UK
| | - Peter Fielding
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, UK
| | - Mark W Sims
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, UK
| | - R A John Challiss
- Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
| | - David Adlam
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, UK
| | - Iain B Squire
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, UK
| | - Richard D Rainbow
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, UK
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Liu K, Kunii N, Sakuma M, Yamaki A, Mizuno S, Sato M, Sakai H, Kado S, Kumagai K, Kojima H, Okabe T, Nagano T, Shirai Y, Sakane F. A novel diacylglycerol kinase α-selective inhibitor, CU-3, induces cancer cell apoptosis and enhances immune response. J Lipid Res 2016; 57:368-79. [PMID: 26768655 DOI: 10.1194/jlr.m062794] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Indexed: 02/02/2023] Open
Abstract
Diacylglycerol kinase (DGK) consists of 10 isozymes. The α-isozyme enhances the proliferation of cancer cells. However, DGKα facilitates the nonresponsive state of immunity known as T-cell anergy; therefore, DGKα enhances malignant traits and suppresses immune surveillance. The aim of this study was to identify a novel small molecule that selectively and potently inhibits DGKα activity. We screened a library containing 9,600 chemical compounds using a newly established high-throughput DGK assay. As a result, we have obtained a promising compound, 5-[(2E)-3-(2-furyl)prop-2-enylidene]-3-[(phenylsulfonyl)amino]2-thioxo-1,3-thiazolidin-4-one) (CU-3), which selectively inhibited DGKα with an IC50 value of 0.6 μM. CU-3 targeted the catalytic region, but not the regulatory region, of DGKα. CU-3 competitively reduced the affinity of DGKα for ATP, but not diacylglycerol or phosphatidylserine. Moreover, this compound induced apoptosis in HepG2 hepatocellular carcinoma and HeLa cervical cancer cells while simultaneously enhancing the interleukin-2 production of Jurkat T cells. Taken together, these results indicate that CU-3 is a selective and potent inhibitor for DGKα and can be an ideal anticancer drug candidate that attenuates cancer cell proliferation and simultaneously enhances immune responses including anticancer immunity.
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Affiliation(s)
- Ke Liu
- Department of Chemistry, Chiba University, Chiba 263-8522, Japan
| | - Naoko Kunii
- Department of Chemistry, Chiba University, Chiba 263-8522, Japan
| | - Megumi Sakuma
- Department of Applied Chemistry in Bioscience, Graduate School of Agricultural Science, Kobe University, Kobe 657-8501, Japan
| | - Atsumi Yamaki
- Department of Chemistry, Chiba University, Chiba 263-8522, Japan
| | - Satoru Mizuno
- Department of Chemistry, Chiba University, Chiba 263-8522, Japan
| | - Mayu Sato
- Department of Chemistry, Chiba University, Chiba 263-8522, Japan
| | - Hiromichi Sakai
- Department of Chemistry, Chiba University, Chiba 263-8522, Japan
| | - Sayaka Kado
- Graduate School of Science and Center for Analytical Instrumentation, Chiba University, Chiba 263-8522, Japan
| | - Kazuo Kumagai
- Drug Discovery Initiative, University of Tokyo, Tokyo 113-0033, Japan
| | - Hirotatsu Kojima
- Drug Discovery Initiative, University of Tokyo, Tokyo 113-0033, Japan
| | - Takayoshi Okabe
- Drug Discovery Initiative, University of Tokyo, Tokyo 113-0033, Japan
| | - Tetsuo Nagano
- Drug Discovery Initiative, University of Tokyo, Tokyo 113-0033, Japan
| | - Yasuhito Shirai
- Department of Applied Chemistry in Bioscience, Graduate School of Agricultural Science, Kobe University, Kobe 657-8501, Japan
| | - Fumio Sakane
- Department of Chemistry, Chiba University, Chiba 263-8522, Japan
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Natarelli L, Ranaldi G, Leoni G, Roselli M, Guantario B, Comitato R, Ambra R, Cimino F, Speciale A, Virgili F, Canali R. Nanomolar Caffeic Acid Decreases Glucose Uptake and the Effects of High Glucose in Endothelial Cells. PLoS One 2015; 10:e0142421. [PMID: 26544184 PMCID: PMC4636304 DOI: 10.1371/journal.pone.0142421] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 10/21/2015] [Indexed: 12/13/2022] Open
Abstract
Epidemiological studies suggest that moderate and prolonged consumption of coffee is associated with a reduced risk of developing type 2 diabetes but the molecular mechanisms underlying this effect are not known. In this study, we report the effects of physiological concentrations of caffeic acid, easily achievable by normal dietary habits, in endothelial cells cultured in 25 mM of glucose (high glucose, HG). In HG, the presence of 10 nM caffeic acid was associated with a decrease of glucose uptake but not to changes of GLUT-1 membrane localization or mRNA levels. Moreover, caffeic acid countered HG-induced loss of barrier integrity, reducing actin rearrangement and FITC-dextran passage. The decreased flux of glucose associated to caffeic acid affected HG induced apoptosis by down-regulating the expression of initiator (caspase 8 and 9) and effector caspases (caspase 7 and 3) and by increasing the levels of phosphorylated Bcl-2. We also observed that caffeic acid in HG condition was associated to a reduction of p65 subunit nuclear levels with respect to HG alone. NF-κB activation has been shown to lead to apoptosis in HG treated cells and the analysis of the expression of a panel of about 90 genes related to NF-κB signaling pathway revealed that caffeic acid significantly influenced gene expression changes induced by HG. In conclusion, our results suggest that caffeic acid, decreasing the metabolic stress induced by HG, allows the activation of survival mechanisms mediated by a different modulation of NF-κB-related signaling pathways and to the activation of anti-apoptotic proteins.
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Affiliation(s)
- Lucia Natarelli
- Council for Agricultural Research and Economics, Food and Nutrition Research Centre, Rome, Italy
| | - Giulia Ranaldi
- Council for Agricultural Research and Economics, Food and Nutrition Research Centre, Rome, Italy
| | - Guido Leoni
- Department of Physics, Sapienza University of Rome, Rome, Italy
| | - Marianna Roselli
- Council for Agricultural Research and Economics, Food and Nutrition Research Centre, Rome, Italy
| | - Barbara Guantario
- Council for Agricultural Research and Economics, Food and Nutrition Research Centre, Rome, Italy
| | - Raffaella Comitato
- Council for Agricultural Research and Economics, Food and Nutrition Research Centre, Rome, Italy
| | - Roberto Ambra
- Council for Agricultural Research and Economics, Food and Nutrition Research Centre, Rome, Italy
| | - Francesco Cimino
- Department of Drug Sciences and Health Products, University of Messina, Messina, Italy
| | - Antonio Speciale
- Department of Drug Sciences and Health Products, University of Messina, Messina, Italy
| | - Fabio Virgili
- Council for Agricultural Research and Economics, Food and Nutrition Research Centre, Rome, Italy
| | - Raffaella Canali
- Council for Agricultural Research and Economics, Food and Nutrition Research Centre, Rome, Italy
- * E-mail:
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Mannerås-Holm L, Kirchner H, Björnholm M, Chibalin AV, Zierath JR. mRNA expression of diacylglycerol kinase isoforms in insulin-sensitive tissues: effects of obesity and insulin resistance. Physiol Rep 2015; 3:3/4/e12372. [PMID: 25847921 PMCID: PMC4425976 DOI: 10.14814/phy2.12372] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Diacylglycerol kinase (DGK) isoforms regulate signal transduction and lipid metabolism. DGKδ deficiency leads to hyperglycemia, peripheral insulin resistance, and metabolic inflexibility. Thus, dysregulation of other DGK isoforms may play a role in metabolic dysfunction. We investigated DGK isoform mRNA expression in extensor digitorum longus (EDL) and soleus muscle, liver as well as subcutaneous and epididymal adipose tissue in C57BL/6J mice and obese and insulin-resistant ob/ob mice. All DGK isoforms, except for DGKκ, were detectable, although with varying mRNA expression. Liver DGK expression was generally lowest, with several isoforms undetectable. In soleus muscle, subcutaneous and epididymal adipose tissue, DGKδ was the most abundant isoform. In EDL muscle, DGKα and DGKζ were the most abundant isoforms. In liver, DGKζ was the most abundant isoform. Comparing obese insulin-resistant ob/ob mice to lean C57BL/6J mice, DGKβ, DGKι, and DGKθ were increased and DGKε expression was decreased in EDL muscle, while DGKβ, DGKη and DGKθ were decreased and DGKδ and DGKι were increased in soleus muscle. In liver, DGKδ and DGKζ expression was increased in ob/ob mice. DGKη was increased in subcutaneous fat, while DGKζ was increased and DGKβ, DGKδ, DGKη and DGKε were decreased in epididymal fat from ob/ob mice. In both adipose tissue depots, DGKα and DGKγ were decreased and DGKι was increased in ob/ob mice. In conclusion, DGK mRNA expression is altered in an isoform- and tissue-dependent manner in obese insulin-resistant ob/ob mice. DGK isoforms likely have divergent functional roles in distinct tissues, which may contribute to metabolic dysfunction.
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Affiliation(s)
- Louise Mannerås-Holm
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Henriette Kirchner
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Marie Björnholm
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Alexander V Chibalin
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Juleen R Zierath
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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Shionoya T, Usuki T, Komenoi S, Isozaki T, Sakai H, Sakane F. Distinct expression and localization of the type II diacylglycerol kinase isozymes δ, η and κ in the mouse reproductive organs. BMC DEVELOPMENTAL BIOLOGY 2015; 15:6. [PMID: 25613821 PMCID: PMC4308931 DOI: 10.1186/s12861-015-0055-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 01/15/2015] [Indexed: 12/30/2022]
Abstract
BACKGROUND We have revealed that the type II diacylglycerol kinases (DGKs) δ, η and κ were expressed in the testis and ovary. However, these enzymes' functions in the reproductive organs remain unknown. RESULTS In this study, we first identified the expression sites of type II DGKs in the mouse reproductive organs in detail. Reverse transcription-polymerase chain reaction and Western blotting confirmed that DGKδ2 (splicing variant 2) but not DGKδ1 (splicing variant 1) and DGKκ were expressed in the testis, ovary and uterus. DGKη1 (splicing variant 1) but not DGKη2 (splicing variant 2) was strongly detected in the ovary and uterus. Interestingly, we found that a new alternative splicing product of the DGKη gene, DGKη3, which lacks exon 26 encoding 31 amino acid residues, was expressed only in the testis. Moreover, we investigated the distribution of type II DGKs in the testis, ovary and uterus through in situ hybridization. DGKδ2 was distributed in the primary spermatocytes of the testis and ovarian follicles. DGKη1 was distributed in the oviductal epithelium of the ovary and the luminal epithelium of the uterus. Intriguingly, DGKη3 was strongly expressed in the secondary spermatocytes and round spermatids of the testis. DGKκ was distributed in the primary and secondary spermatocyte of the testis. CONCLUSION These results indicate that the expression patterns of the type II DGK isoforms δ2, η1, η3 and κ differ from each other, suggesting that these DGK isoforms play specific roles in distinct compartments and developmental stages of the reproductive organs, especially in the processes of spermatogenesis and oocyte maturation.
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Affiliation(s)
- Takao Shionoya
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan.
| | - Takako Usuki
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan.
| | - Suguru Komenoi
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan.
| | - Takeshi Isozaki
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan.
| | - Hiromichi Sakai
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan.
| | - Fumio Sakane
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan.
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38
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Kaneko YK, Ishikawa T. Diacylglycerol Signaling Pathway in Pancreatic β-Cells: An Essential Role of Diacylglycerol Kinase in the Regulation of Insulin Secretion. Biol Pharm Bull 2015; 38:669-73. [DOI: 10.1248/bpb.b15-00060] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Yukiko K. Kaneko
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, University of Shizuoka
| | - Tomohisa Ishikawa
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, University of Shizuoka
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39
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Targeting prostate cancer cell metabolism: impact of hexokinase and CPT-1 enzymes. Tumour Biol 2014; 36:2893-905. [PMID: 25501281 DOI: 10.1007/s13277-014-2919-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 11/28/2014] [Indexed: 10/24/2022] Open
Abstract
Glycolysis has been shown to be required for the cell growth and proliferation in several cancer cells. However, prostate cancer cells were accused of using more fatty acid than glucose to meet their bioenergetic demands. The present study was designed to evaluate the involvement of hexokinase and CPT-1 in the cell growth and proliferation of human prostate cancer cell lines, PC3, and LNCaP-FGC-10. Hexokinase and CPT-1 activities were examined in the presence of different concentrations of their inhibitors, lonidamine and etomoxir, to find the concentration of maximum inhibition ([I max]). To assess cell viability and proliferation, dimethylthiazol (MTT) assay was carried out using [I max] for 24, 48, and 72 h on PC3 and LNCaP cells. Apoptosis was determined using annexin-V, caspase-3 activity assay, Hoechst 33258 staining, and evaluation of mitochondrial membrane potential (MMP). Moreover, ATP levels were measured following lonidamine and etomoxir exposure. In addition, to define the impact of exogenous fatty acid on the cell growth and proliferation, CPT-1 activity was evaluated in the presence of palmitate (50 μM). Hexokinase and CPT-1 activities were significantly inhibited by lonidamine [600 μM] and etomoxir [100 μM] in both cell lines. Treatment of the cells with lonidamine [600 μM] resulted in a significant ATP reduction, cell viability and apoptosis, caspase-3 activity elevation, MMP reduction, and appearance of apoptosis-related morphological changes in the cells. In contrast, etomoxir [100 μM] just decreased ATP levels in both cell lines without significant cell death and apoptosis. Compared with glucose (2 g/L), palmitate intensified CPT-1 activity in both cell lines, especially in LNCaP cells. In addition, activity of CPT-1 was higher in LNCaP than PC3 cells. Our results suggest that prostate cancer cells may metabolize glucose as a source of bioenergetic pathways. ATP could also be produced by long-chain fatty acid oxidation. In addition, these data might suggest that LNCaP is more compatible with palmitate.
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40
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Sims MW, Winter J, Brennan S, Norman RI, André Ng G, Squire IB, Rainbow RD. PKC-mediated toxicity of elevated glucose concentration on cardiomyocyte function. Am J Physiol Heart Circ Physiol 2014; 307:H587-97. [DOI: 10.1152/ajpheart.00894.2013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
While it is well established that mortality risk after myocardial infarction (MI) increases in proportion to blood glucose concentration at the time of admission, it is unclear whether there is a direct, causal relationship. We investigated potential mechanisms by which increased blood glucose may exert cardiotoxicity. Using a Wistar rat or guinea-pig isolated cardiomyocyte model, we investigated the effects on cardiomyocyte function and electrical stability of alterations in extracellular glucose concentration. Contractile function studies using electric field stimulation (EFS), patch-clamp recording, and Ca2+ imaging were used to determine the effects of increased extracellular glucose concentration on cardiomyocyte function. Increasing glucose from 5 to 20 mM caused prolongation of the action potential and increased both basal Ca2+ and variability of the Ca2+ transient amplitude. Elevated extracellular glucose concentration also attenuated the protection afforded by ischemic preconditioning (IPC), as assessed using a simulated ischemia and reperfusion model. Inhibition of PKCα and β, using Gö6976 or specific inhibitor peptides, attenuated the detrimental effects of glucose and restored the cardioprotected phenotype to IPC cells. Increased glucose concentration did not attenuate the cardioprotective role of PKCε, but rather activation of PKCα and β masked its beneficial effect. Elevated extracellular glucose concentration exerts acute cardiotoxicity mediated via PKCα and β. Inhibition of these PKC isoenzymes abolishes the cardiotoxic effects and restores IPC-mediated cardioprotection. These data support a direct link between hyperglycemia and adverse outcome after MI. Cardiac-specific PKCα and β inhibition may be of clinical benefit in this setting.
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Affiliation(s)
- Mark W. Sims
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, United Kingdom; and
| | - James Winter
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, United Kingdom; and
| | - Sean Brennan
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, United Kingdom; and
| | - Robert I. Norman
- Department of Medical and Social Care Education, University of Leicester, Leicester, United Kingdom
| | - G. André Ng
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, United Kingdom; and
| | - Iain B. Squire
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, United Kingdom; and
| | - Richard D. Rainbow
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, United Kingdom; and
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41
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Sakai H, Kado S, Taketomi A, Sakane F. Diacylglycerol kinase δ phosphorylates phosphatidylcholine-specific phospholipase C-dependent, palmitic acid-containing diacylglycerol species in response to high glucose levels. J Biol Chem 2014; 289:26607-26617. [PMID: 25112873 DOI: 10.1074/jbc.m114.590950] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Decreased expression of diacylglycerol (DG) kinase (DGK) δ in skeletal muscles is closely related to the pathogenesis of type 2 diabetes. To identify DG species that are phosphorylated by DGKδ in response to high glucose stimulation, we investigated high glucose-dependent changes in phosphatidic acid (PA) molecular species in mouse C2C12 myoblasts using a newly established liquid chromatography/MS method. We found that the suppression of DGKδ2 expression by DGKδ-specific siRNAs significantly inhibited glucose-dependent increases in 30:0-, 32:0-, and 34:0-PA and moderately attenuated 30:1-, 32:1-, and 34:1-PA. Moreover, overexpression of DGKδ2 also enhanced the production of these PA species. MS/MS analysis revealed that these PA species commonly contain palmitic acid (16:0). D609, an inhibitor of phosphatidylcholine-specific phospholipase C (PC-PLC), significantly inhibited the glucose-stimulated production of the palmitic acid-containing PA species. Moreover, PC-PLC was co-immunoprecipitated with DGKδ2. These results strongly suggest that DGKδ preferably metabolizes palmitic acid-containing DG species supplied from the PC-PLC pathway, but not arachidonic acid (20:4)-containing DG species derived from the phosphatidylinositol turnover, in response to high glucose levels.
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Affiliation(s)
- Hiromichi Sakai
- Department of Chemistry, Graduate School of Science and Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522
| | - Sayaka Kado
- Center for Analytical Instrumentation, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522 and
| | - Akinobu Taketomi
- Department of General Surgery, Graduate School of Medicine, Hokkaido University, North 15, West 7, Kita-ku, Sapporo 060-8638, Japan
| | - Fumio Sakane
- Department of Chemistry, Graduate School of Science and Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522.
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42
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Sakiyama S, Usuki T, Sakai H, Sakane F. Regulation of diacylglycerol kinase δ2 expression in C2C12 skeletal muscle cells by free fatty acids. Lipids 2014; 49:633-40. [PMID: 24852321 DOI: 10.1007/s11745-014-3912-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Accepted: 05/02/2014] [Indexed: 12/14/2022]
Abstract
Decreased expression of diacylglycerol kinase (DGK) δ in skeletal muscles is closely related to the pathogenesis of type 2 diabetes. However, the regulation of DGKδ expression is not well understood. In this study, we found that myristic acid (14:0) significantly increased DGKδ2 protein expression in a dose-dependent manner (EC(50) = 0.16 mM) in mouse C2C12 myotubes. In contrast, oleic [18:1(n-9)], eicosenoic [20:1(n-9)] and erucic [22:1(n-9)] acids markedly decreased DGKδ2 expression. Myristic acid slowly enhanced DGKδ2 expression at the transcription level. Therefore, DGKδ2 expression is positively regulated by the relatively short-chain saturated fatty acid myristic acid but attenuated by n-9 monounsaturated fatty acids.
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Affiliation(s)
- Shizuka Sakiyama
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
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Baldanzi G. Inhibition of diacylglycerol kinases as a physiological way to promote diacylglycerol signaling. Adv Biol Regul 2014; 55:39-49. [PMID: 24582387 DOI: 10.1016/j.jbior.2014.02.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 01/02/2014] [Accepted: 02/02/2014] [Indexed: 01/12/2023]
Abstract
Diacylglycerol is a key regulator of cell physiology, controlling the membrane recruitment and activation of signaling molecules. Accordingly, diacylglycerol generation and metabolism are strictly controlled, allowing for localized regulation of its concentration. While the increased production of diacylglycerol upon receptor triggering is well recognized, the modulation of diacylglycerol metabolism by diacylglycerol kinases (DGKs) is less characterized. Some agonists induce DGK activation and recruitment to the plasma membrane, promoting diacylglycerol metabolism to phosphatidic acid. Conversely, several reports indicate that signaling pathways that selectively inhibits DGK isoforms can enhance cellular diacylglycerol levels and signal transduction. For example, the impairment of DGKθ activity by RhoA binding to the catalytic domain represents a conserved mechanism controlling diacylglycerol signaling from Caenorhabditis elegans motoneurons to mammalian hepatocytes. Similarly, DGKα activity is inhibited in lymphocytes by TCR signaling, thus contributing to a rise in diacylglycerol concentration for downstream signaling. Finally, DGKμ activity is inhibited by ischemia-reperfusion-generated reactive oxygen species in airway endothelial cells, promoting diacylglycerol-mediated ion channel opening and edema. In those systems, DGKs provide a gatekeeper function by blunting diacylglycerol levels or possibly establishing permissive domains for diacylglycerol signaling. In this review, I discuss the possible general relevance of DGK inhibition to enhanced diacylglycerol signaling.
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Affiliation(s)
- Gianluca Baldanzi
- University "A. Avogadro" del Piemonte Orientale, Department of Translational Medicine, via Solaroli 17, 28100 Novara, Italy.
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44
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Kurohane Kaneko Y, Kobayashi Y, Motoki K, Nakata K, Miyagawa S, Yamamoto M, Hayashi D, Shirai Y, Sakane F, Ishikawa T. Depression of type I diacylglycerol kinases in pancreatic β-cells from male mice results in impaired insulin secretion. Endocrinology 2013; 154:4089-98. [PMID: 24035999 DOI: 10.1210/en.2013-1356] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Diacylglycerol kinase (DGK) catalyzes the conversion of diacylglycerol (DAG) to phosphatidic acid. This study investigated the expression and function of DGK in pancreatic β-cells. mRNA expression of type I DGK isoforms (α, β, γ) was detected in mouse pancreatic islets and the β-cell line MIN6. Protein expression of DGKα and DGKγ was also detected in mouse β-cells and MIN6 cells. The type I DGK inhibitor R59949 inhibited high K(+)- and glucose-induced insulin secretion in MIN6 cells. Moreover, single knockdown of DGKα or DGKγ by small interfering RNA slightly but significantly decreased glucose- and high K(+)-induced insulin secretions, and the double knockdown further decreased them to the levels comparable with those induced by R59949. R59949 and DiC8, a membrane permeable DAG analog, decreased intracellular Ca(2+) concentration elevated by glucose and high K(+) in MIN6 cells. Real-time imaging in MIN6 cells expressing green fluorescent protein-tagged DGKα or DGKγ showed that the DGK activator phorbol 12-myristate 13-acetate rapidly induced translocation of DGKγ to the plasma membrane, whereas high K(+) slowly translocated DGKα and DGKγ to the plasma membrane. R59949 increased the DAG content in MIN6 cells when stimulated with high KCl, whereas it did not increase the DAG content but decreased the phosphatidic acid content when stimulated with high glucose. Finally, R59949 was confirmed to inhibit high K(+)-induced insulin secretion from mouse islets and glucose-induced insulin secretion from rat islets. These results suggest that DGKα and DGKγ are present in β-cells and that the depression of these DGKs causes a decrease in intracellular Ca(2+) concentration, thereby reducing insulin secretion.
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45
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Sato M, Liu K, Sasaki S, Kunii N, Sakai H, Mizuno H, Saga H, Sakane F. Evaluations of the selectivities of the diacylglycerol kinase inhibitors R59022 and R59949 among diacylglycerol kinase isozymes using a new non-radioactive assay method. Pharmacology 2013; 92:99-107. [PMID: 23949095 DOI: 10.1159/000351849] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 04/30/2013] [Indexed: 11/19/2022]
Abstract
Ten mammalian diacylglycerol kinase (DGK) isozymes (α-κ) have been identified. Recent studies have revealed that DGK isozymes play pivotal roles in a wide variety of pathophysiological functions. Thus, it is important to be able to easily check DGK activity in each pathophysiological event. Moreover, the conventional DGK assay is quite laborious because it requires the use of a radioisotope and thin-layer chromatography including multiple extraction steps. In order to minimize the laborious procedures, we established a non-radioactive, single well, two-step DGK assay system. We demonstrated that, compared to the conventional method, the new assay system has comparable sensitivity and much higher efficiency, and is effective in detecting potential agents with high reliability (Z'-factor = 0.69 ± 0.12; n = 3). Using the newly developed assay, we comprehensively evaluated the DGK isozyme selectivities of commercially available DGK inhibitors, R59022 and R59949, in vitro. We found that among 10 isozymes, R59022 strongly inhibited type I DGKα and moderately attenuated type III DGKε and type V DGKθ, and that R59949 strongly inhibited type I DGK α and γ, and moderately attenuated type II DGK δ and κ.
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Affiliation(s)
- Mayu Sato
- Department of Chemistry, Graduate School of Science, Chiba University, Inage-ku, Chiba, Japan
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46
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Sakai H, Sakane F. Recent progress on type II diacylglycerol kinases: the physiological functions of diacylglycerol kinase , and and their involvement in disease. J Biochem 2012; 152:397-406. [DOI: 10.1093/jb/mvs104] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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47
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Diacylglycerol kinase δ1 transiently translocates to the plasma membrane in response to high glucose. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1823:2210-6. [PMID: 22974639 DOI: 10.1016/j.bbamcr.2012.08.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2012] [Revised: 08/21/2012] [Accepted: 08/27/2012] [Indexed: 01/21/2023]
Abstract
The type II diacylglycerol kinases (DGKs) contain several functional domains such as a pleckstrin homology (PH) domain, two C1 domains and a sterile α-motif (SAM) domain. It was previously revealed that DGKδ contributes to hyperglycemia-induced peripheral insulin resistance and thereby exacerbate the severity of type 2 diabetes. Moreover, a high extracellular concentration of glucose activated DGKδ in skeletal muscle cells, which was followed by a reduction in the intracellular diacylglycerol levels and the inactivation of protein kinase Cα, the enzyme that phosphorylates and inactivates the insulin receptor. However, the intracellular behavior of DGKδ upon high glucose stimulation remains unclear. In this study, we found that DGKδ1, but not a splice variant DGKδ2 or the other type II DGKη1/2, translocated from the cytoplasm to the plasma membrane in human embryonic kidney HEK293 and mouse myoblast C2C12 cells within 5 min in response to high glucose levels. The translocation was inhibited by phosphatidylinositol 3-kinase inhibitors, LY294002 and GDC-0941, suggesting that the event is regulated via the phosphatidylinositol 3-kinase pathway. Moreover, we revealed that the PH and C1 domains are responsible for the plasma membrane translocation and that the SAM domain negatively regulates the translocation. These results indicate that DGKδ1 is the sole type II DGK isoform that responds rapidly and dynamically to high glucose levels.
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Kawaguchi M, Valencia JC, Namiki T, Suzuki T, Hearing VJ. Diacylglycerol kinase regulates tyrosinase expression and function in human melanocytes. J Invest Dermatol 2012; 132:2791-9. [PMID: 22895365 PMCID: PMC3502659 DOI: 10.1038/jid.2012.261] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Diacylglycerol increases the melanin content of human melanocytes in vitro and increases the pigmentation of guinea pig skin in vivo, but the mechanism(s) underlying those effects remain unknown. In this study, we characterized the role of diacylglycerol kinase (DGK), which phosphorylates diacylglycerol to generate phosphatidic acid, in the regulation of pigmentation. Ten isoforms of DGK have been identified, and we show that DGKζ is the most abundant isoform expressed by human melanocytic cells. Melanin content, tyrosinase activity and tyrosinase protein levels were significantly reduced by a DGK inhibitor, but tyrosinase and MITF mRNA levels were not changed by that inhibition, and there were no effects on the expression of other melanogenesis-related proteins. Isoform-specific siRNAs showed that knockdown of DGKζ decreased melanin content and tyrosinase expression in melanocytic cells. Over-expression of DGKζ increased tyrosinase protein levels, but did not increase tyrosinase mRNA levels. Glycosidase digestion revealed that inhibition of DGK reduced only the mature form of tyrosinase and the decrease of tyrosinase resulting from DGK inhibition could be blocked partially by protease inhibitors. These results suggest that DGK regulates melanogenesis via modulation of the post-translational processing of tyrosinase, which may be related with the protein degradation machinery.
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Affiliation(s)
- Masakazu Kawaguchi
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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Baldanzi G, Pietronave S, Locarno D, Merlin S, Porporato P, Chianale F, Filigheddu N, Cantelmo AR, Albini A, Graziani A, Prat M. Diacylglycerol kinases are essential for hepatocyte growth factor-dependent proliferation and motility of Kaposi's sarcoma cells. Cancer Sci 2011; 102:1329-36. [PMID: 21477072 DOI: 10.1111/j.1349-7006.2011.01953.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Hepatocyte growth factor (HGF) is involved in the pathogenesis of Kaposi's sarcoma (KS), the most frequent neoplasia in patients with AIDS, characterized by proliferating spindle cells, infiltrating inflammatory cells, angiogenesis, edema, and invasiveness. In vitro, this factor sustains the biological behavior of KS derived cells, after activation of its receptor and the downstream MAPK and AKT signals. In other cell types, namely endothelial and epithelial cells, movement, proliferation, and survival stimulated by HGF and other growth factors and cytokines depend on diacylglycerol kinases (DGK). In an effort to identify new intracellular transducers operative in KS cells, which could represent therapeutic targets, we investigated the role of DGK in KS cell movement and proliferation by treating cells with the DGK pharmacological inhibitor R59949. We report that R59949 strongly inhibits HGF-induced KS motility, proliferation, and anchorage-independent growth with only a partial effect on cell adhesion and spreading. R59949 does not affect cell survival, HGF receptor activation, or the classical MAPK and AKT signalling pathways. Furthermore, we carried out an siRNA screen to characterize the DGK isoforms involved in KS motility and anchorage independent growth. Our data indicate a strong involvement of DGK-δ in KS motility and of DGK-ι in anchorage-independent growth. These results indicate that DGK inhibition is sufficient to impair in vitro KS cell proliferation and movement and suggest that selected DGK represent new pharmacological targets to interfere with the malignant properties of KS, independently from the well-known RAS/MAPK and PI3K/AKT pathways.
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Affiliation(s)
- Gianluca Baldanzi
- Department of Experimental and Clinical Medicine, Università del Piemonte Orientale Amedeo Avogadro, Novara IRCCS Multimedica, Milan, Italy
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Berrabah W, Aumercier P, Lefebvre P, Staels B. Control of nuclear receptor activities in metabolism by post-translational modifications. FEBS Lett 2011; 585:1640-50. [PMID: 21486568 DOI: 10.1016/j.febslet.2011.03.066] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Accepted: 03/30/2011] [Indexed: 12/24/2022]
Abstract
Nuclear receptors (NRs) are molecular transducers of endocrine and dietary signals allowing tissues to adapt their transcriptional responses to endogenous or exogenous cues. These signals act in many cases as specific ligands, converting of NRs into transcriptionally active molecules. This on-off mechanism needs, however, to be finely tuned with respect to the tissue environment and adjusted to the organism needs. These subtle adjustments of NR transcriptional activity are brought about by post-translational modifications (PTMs), which can be, in the case of orphan NRs, the sole regulatory mechanism. The role of PTMs, with a more specific focus on phosphorylation, affecting the functions of NR controlling metabolic events is described in this review.
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Affiliation(s)
- Wahiba Berrabah
- Université Lille Nord de France, INSERM, U1011, Lille, France
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