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Mandal N, Stentz F, Asuzu PC, Nyenwe E, Wan J, Dagogo-Jack S. Plasma Sphingolipid Profile of Healthy Black and White Adults Differs Based on Their Parental History of Type 2 Diabetes. J Clin Endocrinol Metab 2024; 109:740-749. [PMID: 37804534 PMCID: PMC10876402 DOI: 10.1210/clinem/dgad595] [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: 07/16/2023] [Revised: 09/18/2023] [Accepted: 10/05/2023] [Indexed: 10/09/2023]
Abstract
CONTEXT Ceramides and sphingolipids have been linked to type 2 diabetes (T2D). The Ceramides and Sphingolipids as Predictors of Incident Dysglycemia (CASPID) study is designed to determine the association of plasma sphingolipids with the pathophysiology of human T2D. OBJECTIVE A comparison of plasma sphingolipids profiles in Black and White adults with (FH+) and without (FH-) family history of T2D. DESIGN We recruited 100 Black and White FH- (54 Black, 46 White) and 140 FH+ (75 Black, 65 White) adults. Fasting plasma levels of 58 sphingolipid species, including 18 each from 3 major classes (ceramides, monohexosylceramides, and sphingomyelins, all with 18:1 sphingoid base) and 4 long-chain sphingoid base-containing species, were measured by liquid chromatography/mass spectrometry. RESULTS Sphingomyelin was the most abundant sphingolipid in plasma (89% in FH-), and was significantly elevated in FH+ subjects (93%). Ceramides and monohexosylceramides comprised 5% and 6% of total sphingolipids in the plasma of FH- subjects, and were reduced significantly in FH+ subjects (3% and 4%, respectively). In FH+ subjects, most ceramide and monohexosylceramide species were decreased but sphingomyelin species were increased. The level of C18:1 species of all 3 classes was elevated in FH+ subjects. CONCLUSION Elevated levels of sphingomyelin, the major sphingolipids of plasma, and oleic acid-containing sphingolipids in healthy FH+ subjects compared with healthy FH- subjects may reflect heritable elements linking sphingolipids and the development of T2D.
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Affiliation(s)
- Nawajes Mandal
- Departments of Ophthalmology, Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
- Research, Memphis VA Medical Center, Memphis, TN 38104, USA
| | - Frankie Stentz
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Peace Chiamaka Asuzu
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Ebenezer Nyenwe
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Jim Wan
- Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Sam Dagogo-Jack
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Tennessee Health Science Center, Memphis, TN 38163, USA
- General Clinical Research Center, University of Tennessee Health Science Center, Memphis, TN 38163, USA
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Lopes-Virella MF, Hammad SM, Baker NL, Klein RL, Hunt KJ. Circulating Lipoprotein Sphingolipids in Chronic Kidney Disease with and without Diabetes. Biomedicines 2024; 12:190. [PMID: 38255295 PMCID: PMC10813484 DOI: 10.3390/biomedicines12010190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 12/25/2023] [Accepted: 01/08/2024] [Indexed: 01/24/2024] Open
Abstract
Abnormalities of sphingolipid metabolism play an important role in diabetes. We compared sphingolipid levels in plasma and in isolated lipoproteins between healthy control subjects and two groups of patients, one with chronic kidney disease without diabetes (ND-CKD), and the other with type 2 diabetes and macroalbuminuria (D-MA). Ceramides, sphingomyelins, and sphingoid bases and their phosphates in LDL were higher in ND-CKD and in D-MA patients compared to controls. However, ceramides and sphingoid bases in HDL2 and HDL3 were lower in ND-CKD and in D-MA patients than in controls. Sphingomyelins in HDL2 and HDL3 were lower in D-MA patients than in controls but were normal in ND-CKD patients. Compared to controls, lactosylceramides in LDL and VLDL were higher in ND-CKD patients but not in D-MA patients. However, lactosylceramides in HDL2 and HDL3 were lower in both ND-CKD and D-MA patients than in controls. Plasma hexosylceramides in ND-CKD patients were increased and sphingoid bases decreased in both ND-CKD and D-MA patients. However, hexosylceramides in LDL, HDL2, and HDL3 were higher in ND-CKD patients than in controls. In D-MA patients, only C16:0 hexosylceramide in LDL was higher than in controls. The data suggest that sphingolipid measurement in lipoproteins, rather than in whole plasma, is crucial to decipher the role of sphingolipids in kidney disease.
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Affiliation(s)
- Maria F. Lopes-Virella
- Department of Medicine, Division of Diabetes, Endocrinology and Medical Genetics, Medical University of South Carolina, Charleston, SC 29425, USA
- Ralph H. Johnson VA Medical Center, Charleston, SC 29401, USA;
| | - Samar M. Hammad
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Nathaniel L. Baker
- Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC 29425, USA;
| | - Richard L. Klein
- Department of Medicine, Division of Diabetes, Endocrinology and Medical Genetics, Medical University of South Carolina, Charleston, SC 29425, USA
- Ralph H. Johnson VA Medical Center, Charleston, SC 29401, USA;
| | - Kelly J. Hunt
- Ralph H. Johnson VA Medical Center, Charleston, SC 29401, USA;
- Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC 29425, USA;
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Hammad SM, Lopes-Virella MF. Circulating Sphingolipids in Insulin Resistance, Diabetes and Associated Complications. Int J Mol Sci 2023; 24:14015. [PMID: 37762318 PMCID: PMC10531201 DOI: 10.3390/ijms241814015] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 09/05/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023] Open
Abstract
Sphingolipids play an important role in the development of diabetes, both type 1 and type 2 diabetes, as well as in the development of both micro- and macro-vascular complications. Several reviews have been published concerning the role of sphingolipids in diabetes but most of the emphasis has been on the possible mechanisms by which sphingolipids, mainly ceramides, contribute to the development of diabetes. Research on circulating levels of the different classes of sphingolipids in serum and in lipoproteins and their importance as biomarkers to predict not only the development of diabetes but also of its complications has only recently emerged and it is still in its infancy. This review summarizes the previously published literature concerning sphingolipid-mediated mechanisms involved in the development of diabetes and its complications, focusing on how circulating plasma sphingolipid levels and the relative content carried by the different lipoproteins may impact their role as possible biomarkers both in the development of diabetes and mainly in the development of diabetic complications. Further studies in this field may open new therapeutic avenues to prevent or arrest/reduce both the development of diabetes and progression of its complications.
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Affiliation(s)
- Samar M. Hammad
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Maria F. Lopes-Virella
- Division of Endocrinology, Diabetes and Medical Genetics, Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA
- Ralph H. Johnson VA Medical Center, Charleston, SC 29425, USA
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4
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Meter D, Racetin A, Vukojević K, Balog M, Ivić V, Zjalić M, Heffer M, Filipović N. A Lack of GD3 Synthase Leads to Impaired Renal Expression of Connexins and Pannexin1 in St8sia1 Knockout Mice. Int J Mol Sci 2022; 23:ijms23116237. [PMID: 35682927 PMCID: PMC9181035 DOI: 10.3390/ijms23116237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 05/28/2022] [Accepted: 05/30/2022] [Indexed: 02/01/2023] Open
Abstract
The aim of this study was to determine the effects of altered ganglioside composition on the expression of Cx37, Cx40, Cx43, Cx45, and Panx1 in different kidney regions of St8sia1 gene knockout mice (St8sia1 KO) lacking the GD3 synthase enzyme. Experiments were performed in twelve male 6-month-old mice: four wild-type (C57BL/6-type, WT) and eight St8sia1 KO mice. After euthanasia, kidney tissue was harvested, embedded in paraffin wax, and processed for immunohistochemistry. The expression of connexins and Panx1 was determined in different regions of the kidney: cortex (CTX.), outer stripe of outer medulla (O.S.), inner stripe of outer medulla (IN.S.), and inner medulla (IN.MED.). We determined significantly lower expression of Cx37, Cx40, Cx45, and Panx1 in different parts of the kidneys of St8sia1 KO mice compared with WT. The most consistent decrease was found in the O.S. where all markers (Cx 37, 40, 45 and Panx1) were disrupted in St8si1 KO mice. In the CTX. region, we observed decrease in the expression of Cx37, Cx45, and Panx1, while reduced expression of Cx37 and Panx1 was more specific to IN.S. The results of the present study suggest that deficiency of GD3 synthase in St8sia1 KO mice leads to disruption of renal Cx expression, which is probably related to alteration of ganglioside composition.
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Affiliation(s)
- Diana Meter
- Department of Rheumatology and Clinical Immunology, University Hospital of Split, Spinčićeva 1, 21000 Split, Croatia;
| | - Anita Racetin
- Laboratory for Early Human Development, Department of Anatomy, Histology and Embryology, University of Split School of Medicine, Šoltanska 2, 21000 Split, Croatia; (A.R.); (K.V.)
| | - Katarina Vukojević
- Laboratory for Early Human Development, Department of Anatomy, Histology and Embryology, University of Split School of Medicine, Šoltanska 2, 21000 Split, Croatia; (A.R.); (K.V.)
- Laboratory for Neurocardiology, Department of Anatomy, Histology and Embryology, University of Split School of Medicine, Šoltanska 2, 21000 Split, Croatia
| | - Marta Balog
- Department of Medical Biology and Genetics, Faculty of Medicine Osijek, Josip Juraj Strossmayer University of Osijek, Huttlerova 4, 31000 Osijek, Croatia; (M.B.); (V.I.); (M.H.)
| | - Vedrana Ivić
- Department of Medical Biology and Genetics, Faculty of Medicine Osijek, Josip Juraj Strossmayer University of Osijek, Huttlerova 4, 31000 Osijek, Croatia; (M.B.); (V.I.); (M.H.)
| | - Milorad Zjalić
- Department of Molecular Medicine and Biotechnology, Faculty of Medicine Rijeka, University of Rijeka, Branchetta brothers 20, 51000 Rijeka, Croatia;
| | - Marija Heffer
- Department of Medical Biology and Genetics, Faculty of Medicine Osijek, Josip Juraj Strossmayer University of Osijek, Huttlerova 4, 31000 Osijek, Croatia; (M.B.); (V.I.); (M.H.)
| | - Natalija Filipović
- Laboratory for Early Human Development, Department of Anatomy, Histology and Embryology, University of Split School of Medicine, Šoltanska 2, 21000 Split, Croatia; (A.R.); (K.V.)
- Correspondence:
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Hammad SM, Hunt KJ, Baker NL, Klein RL, Lopes-Virella MF. Diabetes and kidney dysfunction markedly alter the content of sphingolipids carried by circulating lipoproteins. J Clin Lipidol 2022; 16:173-183. [DOI: 10.1016/j.jacl.2021.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 11/18/2021] [Accepted: 12/28/2021] [Indexed: 10/19/2022]
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Semler A, Hammad S, Lopes-Virella MF, Klein RL, Huang Y. Deoxysphingolipids Upregulate MMP-1, Downregulate TIMP-1, and Induce Cytotoxicity in Human Schwann Cells. Neuromolecular Med 2021; 24:352-362. [PMID: 34853975 DOI: 10.1007/s12017-021-08698-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 11/18/2021] [Indexed: 11/29/2022]
Abstract
Sphingolipids are a heterogeneous class of lipids and essential components of the plasma membrane and plasma lipoproteins. Studies have shown that plasma deoxysphingolipid (DSL), a newly identified sphingolipid class, is increased in diabetic patients and associated with diabetic neuropathy. However, it remains unknown if there is a causal relationship between plasma DSL increase and diabetic neuropathy. Since matrix metalloproteinases (MMPs) play an important role in diabetic neuropathy by degrading extracellular matrix in the peripheral nervous system, we investigated the effect of DSLs on the expression of MMPs and tissue inhibitor of metalloproteinase (TIMPs), and cytotoxicity in human Schwann cells. We quantified protein secretion, gene expression, and collagenase activity, and performed cytotoxicity assays. Results showed that DSLs upregulated MMP-1, downregulated TIMP-1, and induced cytotoxicity in Schwann cells. Furthermore, we quantified DSLs in VLDL, LDL, HDL2, and HDL3 isolated from type 2 diabetes mellitus (T2DM) patients with or without neuropathy. Interestingly, lipidomic analysis showed that only HDL2 isolated from T2DM patients with neuropathy contains significantly higher level of DSLs than that isolated from T2DM patients without neuropathy. Additionally, results showed that HDL2 isolated from T2DM patients with neuropathy was more potent than that isolated from T2DM patients without neuropathy in upregulating MMP-1, downregulating TIMP-1, and stimulating collagenase activity in Schwann cell. Taken together, this study demonstrated for the first time a potential causal relationship between DSLs and diabetic neuropathy and that DSL-containing HDL2 from T2DM patients with neuropathy was more potent than that from T2DM patients without neuropathy in stimulating collagenase activity.
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Affiliation(s)
- Andrea Semler
- Division of Endocrinology, Diabetes and Medical Genetics, Department of Medicine, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Samar Hammad
- Department of Regenerative Medicine & Cell Biology, Medical University of South Carolina, Charleston, USA
| | - Maria F Lopes-Virella
- Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC, 29401, USA.,Division of Endocrinology, Diabetes and Medical Genetics, Department of Medicine, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Richard L Klein
- Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC, 29401, USA.,Division of Endocrinology, Diabetes and Medical Genetics, Department of Medicine, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Yan Huang
- Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC, 29401, USA. .,Division of Endocrinology, Diabetes and Medical Genetics, Department of Medicine, Medical University of South Carolina, Charleston, SC, 29425, USA.
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Keppley LJW, Walker SJ, Gademsey AN, Smith JP, Keller SR, Kester M, Fox TE. Nervonic acid limits weight gain in a mouse model of diet-induced obesity. FASEB J 2020; 34:15314-15326. [PMID: 32959931 DOI: 10.1096/fj.202000525r] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 09/03/2020] [Accepted: 09/09/2020] [Indexed: 12/18/2022]
Abstract
Lipid perturbations contribute to detrimental outcomes in obesity. We previously demonstrated that nervonic acid, a C24:1 ω-9 fatty acid, predominantly acylated to sphingolipids, including ceramides, are selectively reduced in a mouse model of obesity. It is currently unknown if deficiency of nervonic acid-sphingolipid metabolites contribute to complications of obesity. Mice were fed a standard diet, a high fat diet, or these diets supplemented isocalorically with nervonic acid. The primary objective was to determine if dietary nervonic acid content alters the metabolic phenotype in mice fed a high fat diet. Furthermore, we investigated if nervonic acid alters markers of impaired fatty acid oxidation in the liver. We observed that a nervonic acid-enriched isocaloric diet reduced weight gain and adiposity in mice fed a high fat diet. The nervonic acid enrichment led to increased C24:1-ceramides and improved several metabolic parameters including blood glucose levels, and insulin and glucose tolerance. Mechanistically, nervonic acid supplementation increased PPARα and PGC1α expression and improved the acylcarnitine profile in liver. These alterations indicate improved energy metabolism through increased β-oxidation of fatty acids. Taken together, increasing dietary nervonic acid improves metabolic parameters in mice fed a high fat diet. Strategies that prevent deficiency of, or restore, nervonic acid may represent an effective strategy to treat obesity and obesity-related complications.
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Affiliation(s)
- Laura J W Keppley
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Susan J Walker
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Alexis N Gademsey
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Jason P Smith
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Susanna R Keller
- Medicine: Endocrinology and Metabolism, University of Virginia, Charlottesville, VA, USA
| | - Mark Kester
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Todd E Fox
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA.,Department of Ophthalmology, University of Virginia, Charlottesville, VA, USA
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Insulin Independence in Newly Diagnosed Type 1 Diabetes Patient following Fenofibrate Treatment. Case Rep Med 2020; 2020:6865190. [PMID: 32508930 PMCID: PMC7245672 DOI: 10.1155/2020/6865190] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 04/29/2020] [Indexed: 12/20/2022] Open
Abstract
A 19-year-old girl was diagnosed with type 1 diabetes and showing polydipsia and polyuria. She was double autoantibody-positive and had a diabetes-prone tissue type. She was immediately started on insulin. Fenofibrate treatment (160 mg daily) was initiated seven days after diagnosis. The need for insulin quickly declined, and she took her last dose of insulin 19 days after the first dose of fenofibrate, having regained endogenous control of blood glucose concentrations. She has now been insulin independent for one year and 9 months. Unstimulated C-peptide has increased by 51% (317 to 479 pmol/l), and IA-2 autoantibody level has decreased by 65% (49 to 17 × 103 arbitrary units). Fenofibrate is a widely used drug for reducing triglyceride and cholesterol levels. Fenofibrate reverses and prevents autoimmune diabetes in nonobese diabetic (NOD) mice by increasing the amount of the sphingolipid sulfatide in islets. Sphingolipid metabolism is otherwise abnormal in the islets at diagnosis of type 1 diabetes. In conclusion, we describe a 19-year-old patient with classical newly diagnosed type 1 diabetes, which following fenofibrate treatment has been without insulin for 21 months.
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Transcriptomics Reveal Altered Metabolic and Signaling Pathways in Podocytes Exposed to C16 Ceramide-Enriched Lipoproteins. Genes (Basel) 2020; 11:genes11020178. [PMID: 32045989 PMCID: PMC7073971 DOI: 10.3390/genes11020178] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 02/03/2020] [Accepted: 02/04/2020] [Indexed: 11/16/2022] Open
Abstract
Sphingolipids are bioactive lipids associated with cellular membranes and plasma lipoproteins, and their synthesis and degradation are tightly regulated. We have previously determined that low plasma concentrations of certain ceramide species predict the development of nephropathy in diabetes patients with normal albumin excretion rates at baseline. Herein, we tested the hypothesis that altering the sphingolipid content of circulating lipoproteins can alter the metabolic and signaling pathways in podocytes, whose dysfunction leads to an impairment of glomerular filtration. Cultured human podocytes were treated with lipoproteins from healthy subjects enriched in vitro with C16 ceramide, or D-erythro 2-hydroxy C16 ceramide, a ceramide naturally found in skin. The RNA-Seq data demonstrated differential expression of genes regulating sphingolipid metabolism, sphingolipid signaling, and mTOR signaling pathways. A multiplex analysis of mTOR signaling pathway intermediates showed that the majority (eight) of the pathway phosphorylated proteins measured (eleven) were significantly downregulated in response to C16 ceramide-enriched HDL2 compared to HDL2 alone and hydroxy ceramide-enriched HDL2. In contrast, C16 ceramide-enriched HDL3 upregulated the phosphorylation of four intermediates in the mTOR pathway. These findings highlight a possible role for lipoprotein-associated sphingolipids in regulating metabolic and signaling pathways in podocytes and could lead to novel therapeutic targets in glomerular kidney diseases.
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Mallela SK, Mitrofanova A, Merscher S, Fornoni A. Regulation of the amount of ceramide-1-phosphate synthesized in differentiated human podocytes. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1864:158517. [PMID: 31487557 PMCID: PMC6832884 DOI: 10.1016/j.bbalip.2019.158517] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 08/09/2019] [Accepted: 08/26/2019] [Indexed: 12/14/2022]
Abstract
Sphingolipids have important functions as structural components of cells but they also function as signaling molecules regulating different cellular processes such as apoptosis, cell proliferation, cell migration, cell division and inflammation. Hence, a tight regulation of the sphingolipid homeostasis is essential to maintain proper cellular functions. Mammalian ORMDL proteins are orthologues of the yeast ORM1/2 proteins, which regulate ceramide synthesis in yeast. ORMDL proteins inhibit serine palmitoyltransferase (SPT), the enzyme regulating a rate-limiting step of the sphingolipid pathway to control the levels of ceramides and other sphingolipids. Sphingomyelinase phosphodiesterase like 3b (SMPDL3b) is a glycosylphosphatidylinositol (GPI) anchored protein in the plasma membrane (PM) and determines membrane fluidity in macrophages. We previously showed that differential expression of SMPDL3b alters the availability of Ceramide-1-phosphate (C1P) in human podocytes, which are terminally differentiated cells of the kidney filtration barrier. This observation lead us to investigate if SMPDL3b controls C1P availability in human podocytes by interfering with ceramide kinase (CERK) expression and function. We found that SMPDL3b interacts with CERK and can bind to C1P in vitro. Furthermore, CERK expression is reduced when SMPDL3b expression is silenced. These observations led us to propose that one of the mechanisms by which SMPDL3b influences the amount of C1P available in the podocytes is by interfering with the function of CERK thereby maintaining a balance in the levels of the C1P in podocytes.
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Affiliation(s)
- Shamroop Kumar Mallela
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, FL, USA; Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, FL, USA.
| | - Alla Mitrofanova
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, FL, USA; Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Sandra Merscher
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, FL, USA; Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Alessia Fornoni
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, FL, USA; Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, FL, USA.
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11
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Lopes-Virella MF, Baker NL, Hunt KJ, Hammad SM, Arthur J, Virella G, Klein RL. Glycosylated sphingolipids and progression to kidney dysfunction in type 1 diabetes. J Clin Lipidol 2019; 13:481-491.e1. [PMID: 31043336 DOI: 10.1016/j.jacl.2019.03.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 03/19/2019] [Accepted: 03/26/2019] [Indexed: 12/14/2022]
Abstract
BACKGROUND Glycosphingolipids are important components of cell membranes, modulators of cell-cell interactions and cell recognition, and have recently emerged as bioactive molecules and important players in nearly all cell biological processes. We previously have shown that decreased plasma levels of long and very long species of ceramides were able to predict the development of macroalbuminuria (MA) in type 1 diabetes. OBJECTIVE This study proposed to examine whether plasma glycosphingolipids could predict development of diabetic nephropathy, assessed as MA or chronic kidney disease (CKD). METHODS Measurement of plasma hexosylceramides (H) and lactosylceramides (L) were conducted in the Lipidomics Core Facility of our Institution in a subcohort of 432 patients from the DCCT/Epidemiology of Diabetes Interventions and Complications cohort in plasma collected at entry into the study. Inverse probability weighted Cox proportional hazards regression models were used to assess the effect of glycosphingolipids levels on the risk of developing MA (albumin excretion rate ≥300 mg/24 hours) or CKD (glomerular filtration rate <60 mL/min) over a period of 21 to 28 years. RESULTS Decreases of several long and very long chain lactosylceramides were significantly associated with increased risk of progression to MA but not CKD. Among the hexosylceramides, the only significant association observed was between one of its minor species C18:1-H and CKD. CONCLUSION Our findings showed that decreased levels of long and very long lactosylceramides were able to predict the development of MA in type 1 diabetes. This finding is similar to previous findings showing that low levels of long and very long ceramides were also able to predict development of MA in the same cohort. Further studies are needed to determine the changes in sphingolipid metabolism leading to the development of complications.
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Affiliation(s)
- Maria F Lopes-Virella
- Division of Diabetes, Endocrinology and Medical Genetics, Department of Medicine, Medical University of South Carolina, Charleston, SC, USA; Ralph H. Johnson VA Medical Center, Charleston, SC, USA.
| | - Nathaniel L Baker
- Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC, USA
| | - Kelly J Hunt
- Ralph H. Johnson VA Medical Center, Charleston, SC, USA; Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC, USA
| | - Samar M Hammad
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, USA
| | - John Arthur
- Division of Nephrology, Department of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Gabriel Virella
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, USA
| | - Richard L Klein
- Division of Diabetes, Endocrinology and Medical Genetics, Department of Medicine, Medical University of South Carolina, Charleston, SC, USA; Ralph H. Johnson VA Medical Center, Charleston, SC, USA
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Bhat OM, Yuan X, Li G, Lee R, Li PL. Sphingolipids and Redox Signaling in Renal Regulation and Chronic Kidney Diseases. Antioxid Redox Signal 2018; 28:1008-1026. [PMID: 29121774 PMCID: PMC5849286 DOI: 10.1089/ars.2017.7129] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 10/30/2017] [Accepted: 11/04/2017] [Indexed: 01/04/2023]
Abstract
Significance: Sphingolipids play critical roles in the membrane biology and intracellular signaling events that influence cellular behavior and function. Our review focuses on the cellular mechanisms and functional relevance of the cross talk between sphingolipids and redox signaling, which may be critically implicated in the pathogenesis of different renal diseases. Recent Advances: Reactive oxygen species (ROS) and sphingolipids can regulate cellular redox homeostasis through the regulation of NADPH oxidase, mitochondrial integrity, nitric oxide synthase (NOS), and antioxidant enzymes. Over the last two decades, there have been significant advancements in the field of sphingolipid research, and it was in 2010 for the first time that sphingolipid receptor modulator was exploited as a therapeutic in humans. The cross talk of sphingolipids with redox signaling pathways becomes an important mechanism in the development of many different diseases such as renal diseases. Critical Issues: The critical issues to be addressed in this review are how sphingolipids interact with the redox signaling pathway to regulate renal function and even result in chronic kidney diseases. Ceramide, sphingosine, and sphingosine-1-phosphate (S1P) as main signaling sphingolipids are discussed in more detail. Future Directions: Although sphingolipids and ROS may mediate or modulate cellular responses to physiological and pathological stimuli, more translational studies and mechanistic pursuit in a tissue- or cell-specific way are needed to enhance our understanding of this important topic and to develop effective therapeutic strategies to treat diseases associated with redox signaling and sphingolipid cross talk. Antioxid. Redox Signal. 28, 1008-1026.
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Affiliation(s)
- Owais M Bhat
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Xinxu Yuan
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Guangbi Li
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - RaMi Lee
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Pin-Lan Li
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
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Increased Plasma Levels of Select Deoxy-ceramide and Ceramide Species are Associated with Increased Odds of Diabetic Neuropathy in Type 1 Diabetes: A Pilot Study. Neuromolecular Med 2016; 19:46-56. [PMID: 27388466 DOI: 10.1007/s12017-016-8423-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 06/30/2016] [Indexed: 12/14/2022]
Abstract
Plasma deoxy-sphingoid bases are elevated in type 2 diabetes patients and correlate with the stage of diabetic distal sensorimotor polyneuropathy; however, associations between deoxy-sphingolipids (DSL) and neuropathy in type 1 diabetes have not been examined. The primary aim of this exploratory pilot study was to assess the associations between multiple sphingolipid species including DSL and free amino acids and the presence of symptomatic neuropathy in a DCCT/EDIC type 1 diabetes subcohort. Using mass spectroscopy, plasma levels of DSL and free amino acids in DCCT/EDIC type 1 diabetes participants (n = 80), with and without symptoms of neuropathy, were investigated. Patient-determined neuropathy was based on 15-item self-administered questionnaire (Michigan Neuropathy Screening Instrument) developed to assess distal symmetrical peripheral neuropathy in diabetes. Patients who scored ≥4, or reported inability to sense their feet during walking or to distinguish hot from cold water while bathing were considered neuropathic. Plasma levels of ceramide, sphingomyelin, hexosyl- and lactosylceramide species, and amino acids were measured and analyzed relative to neuropathy status in the patient. Deoxy-C24-ceramide, C24- and C26-ceramide were higher in patients with neuropathy than those without neuropathy. Cysteine was higher in patients with neuropathy. No differences in other sphingolipids or amino acids were detected. The covariate-adjusted Odds Ratios of positive patient-reported neuropathy was associated with increased levels of deoxy-C24-, and deoxy-C24:1-ceramide; C22-, C24-, and C26-ceramide; and cysteine. Plasma deoxy-ceramide and ceramide species may have potential diagnostic and prognostic significance in diabetic neuropathy.
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Klein RL, Hammad SM, Baker NL, Hunt KJ, Al Gadban MM, Cleary PA, Virella G, Lopes-Virella MF. Decreased plasma levels of select very long chain ceramide species are associated with the development of nephropathy in type 1 diabetes. Metabolism 2014; 63:1287-95. [PMID: 25088746 PMCID: PMC5894336 DOI: 10.1016/j.metabol.2014.07.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 06/25/2014] [Accepted: 07/01/2014] [Indexed: 11/20/2022]
Abstract
OBJECTIVE Sphingolipid metabolism is altered in diabetes and we analyzed the plasma concentrations of sphingolipid species to investigate their association with the development of albuminuria in type 1 patients with diabetes. MATERIALS AND METHODS Samples were collected from 497 type 1 diabetic patients during their enrollment into the Diabetes Control and Complications Trial (DCCT). We determined plasma concentrations of multiple ceramide species and individual sphingoid bases and their phosphates using high performance liquid chromatography-tandem mass spectrometry and investigated their association with the development of albuminuria during 14-20 years of follow-up. RESULTS Patients exhibited normal albumin excretion rates (AER <40 mg/24h) at the time of plasma sampling. Although the majority of patients (N = 291; 59%) exhibited normal levels of albuminuria throughout follow-up, 141 patients (28%) progressed to microalbuminuria (40 mg/24h ≤ AER<300 mg/24h), while 65 (13%) progressed to macroalbuminuria (AER ≥ 300 mg/24h). To test the association of log transformed plasma sphingolipid level with the development of albuminuria, generalized logistic regression models were used where normal, micro- and macroalbuminuria were the outcomes of interest. Models were adjusted for DCCT treatment group, baseline retinopathy, gender, baseline HbA1c %, age, AER, lipid levels, diabetes duration, and the use of ACE/ARB drugs. Increased plasma levels of very long, but not long chain ceramide species measured at DCCT baseline were associated with decreased odds to develop macroalbuminuria during the subsequent nineteen years (DCCT Baseline to EDIC year 8). CONCLUSION These studies demonstrate, prospectively, that decreased plasma levels of select ceramide species are associated with the development of macroalbuminuria in type 1 diabetes.
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Affiliation(s)
- Richard L Klein
- Division of Endocrinology, Metabolism, and Medical Genetics, Department of Medicine, Medical University of South Carolina, Charleston, SC, USA; Research Service, Ralph H. Johnson Department of Veterans Affairs Medical Center, Charleston, SC, USA.
| | - Samar M Hammad
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, USA.
| | - Nathaniel L Baker
- Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC, USA
| | - Kelly J Hunt
- Research Service, Ralph H. Johnson Department of Veterans Affairs Medical Center, Charleston, SC, USA; Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC, USA
| | - Mohammed M Al Gadban
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, USA
| | - Patricia A Cleary
- The Biostatistics Center, George Washington University, Washington, DC, USA
| | - Gabriel Virella
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, USA
| | - Maria F Lopes-Virella
- Division of Endocrinology, Metabolism, and Medical Genetics, Department of Medicine, Medical University of South Carolina, Charleston, SC, USA; Research Service, Ralph H. Johnson Department of Veterans Affairs Medical Center, Charleston, SC, USA
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Ozay R, Uzar E, Aktas A, Uyar ME, Gürer B, Evliyaoglu O, Cetinalp NE, Turkay C. The role of oxidative stress and inflammatory response in high-fat diet induced peripheral neuropathy. J Chem Neuroanat 2014; 55:51-7. [PMID: 24407112 DOI: 10.1016/j.jchemneu.2013.12.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Revised: 12/25/2013] [Accepted: 12/27/2013] [Indexed: 12/17/2022]
Abstract
OBJECTIVE Earlier studies suggest that high-calorie diet is an important risk factor for neuronal damage resulting from oxidative stress of lipid metabolism. In our experimental study of rats under high-fat diet, oxidative stress markers and axonal degeneration parameters were used to observe the sciatic nerve neuropathy. The aim of this study is to evaluate the pathophysiology of neuropathy induced by high-fat diet. METHODS A total of 14 male rats (Wistar albino) were randomly divided into two experimental groups as follows; control group (n=7) and the model group (n=7); while control group was fed with standard diet; where the model group was fed with a high-fat diet for 12 weeks. At the end of 12 weeks, the lipid profile and blood glucose levels, interleukin-1β (IL-1), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and transforming growth factor-β (TGF-β) levels were studied. Tissue malondialdehyde (MDA), nitric oxide (NO) levels and super-oxide dismutase (SOD), paraoxonase-1 (PON-1) and glutathione peroxidase (GPx) activities were studied. The distal blocks of the left sciatic nerves were evaluated for histomorphological analysis (including mean axon area, axon numbers, nerve fiber diameters, axon diameters, and thickness of myelin sheets). RESULTS Body weights, serum glucose and high-density lipoprotein (HDL) levels of rats were found not statistically significantly different compared between the model and the control groups (p>0.05). Serum cholesterol, triglyceride, TGF-β and TNF-α levels were significantly higher in the model group when compared with the control group (p<0.05). IL-1 and IL-6 levels were not statistically significantly different compared between the model group and the control group (p>0.05). The MDA and NO levels and the SOD and GPx activities of the sciatic nerves in model group were statistically significantly higher than the control group (p<0.05). In addition, the activities of PON-1 were statistically significantly lower in the model group when compared with the control group (p<0.05). The difference in the total number of myelinated axons between the control group and the model group was not statistically significant (p>0.05). The nerve fiber diameter and the thickness of the myelin sheet were statistically significantly lower in the model group when compared with the control group (p<0.05). The axon diameter and area were significantly decreased in the model group when compared with the control group (p<0.05). CONCLUSION Our results support that dyslipidemia is an independent risk factor for the development of neuropathy. In addition, we postulated that oxidative stress and inflammatory response may play an important role in the pathogenesis of high-fat diet induced neuropathy.
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Affiliation(s)
- Rafet Ozay
- Ministry of Health, Diskapi Yildirim Beyazit Education and Research Hospital, Neurosurgery Clinic, Turkey
| | - Ertugrul Uzar
- Dicle University, Department of Neurology, School of Medicine, Diyarbakır, Turkey
| | - Abit Aktas
- Istanbul University, Faculty of Veterinary Medicine, Department of Histology and Embriology, Istanbul, Turkey
| | - Mehtap Erkmen Uyar
- Başkent University, Medical School, Department of Nephrology, Ankara, Turkey
| | - Bora Gürer
- Ministry of Health, Diskapi Yildirim Beyazit Education and Research Hospital, Neurosurgery Clinic, Turkey.
| | - Osman Evliyaoglu
- Dicle University, Department of Biochemistry, School of Medicine, Diyarbakır, Turkey
| | - Nuri Eralp Cetinalp
- Etlik Ihtisas Research and Educational Hospital, Department of Neurosurgery, Ankara, Turkey
| | - Cansel Turkay
- Fatih University, Department of Gastroenterology, School of Medicine, Ankara, Turkey
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In-vial dual extraction liquid chromatography coupled to mass spectrometry applied to streptozotocin-treated diabetic rats. Tips and pitfalls of the method. J Chromatogr A 2013; 1304:52-60. [DOI: 10.1016/j.chroma.2013.07.029] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 05/09/2013] [Accepted: 07/06/2013] [Indexed: 01/06/2023]
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17
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Wolden-Kirk H, Overbergh L, Gysemans C, Brusgaard K, Naamane N, Van Lommel L, Schuit F, Eizirik DL, Christesen H, Mathieu C. Unraveling the effects of 1,25OH2D3 on global gene expression in pancreatic islets. J Steroid Biochem Mol Biol 2013; 136:68-79. [PMID: 23137852 DOI: 10.1016/j.jsbmb.2012.10.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Revised: 10/19/2012] [Accepted: 10/20/2012] [Indexed: 01/01/2023]
Abstract
INTRODUCTION Vitamin D deficiency has been linked to type 1 and 2 diabetes, whereas supplementation may prevent both diseases. However, the extent of the effects of vitamin D or its metabolites directly on pancreatic islets is still largely unknown. The aim of the present study was to investigate how active vitamin D, 1,25(OH)2D3, affects beta cells directly by establishing its effects on global gene expression in healthy murine islets. MATERIALS AND METHODS Pancreatic islets were isolated from 2 to 3 week old C57BL/6 mice and cultured in vitro with 1,25(OH)2D3 or vehicle for 6 and 24h. Total RNA was extracted from the islets and the effects on global gene expression were analyzed using Affymetrix microarrays. RESULTS AND DISCUSSION Exposure to 1,25(OH)2D3 compared to vehicle resulted in 306 and 151 differentially expressed genes after 6 and 24h, respectively (n=4, >1.3-fold, p<0.02). Of these 220 were up-regulated, whereas 86 displayed a decreased expression after 6h. Furthermore, expression levels were increased for 124 and decreased for 27 genes following 24h of exposure. Formation of intercellular junctions, cytoskeletal organization, and intracellular trafficking as well as lipid metabolism and ion transport were among the most affected gene classes. Effects on several genes already identified as being part of vitamin D signaling in other cell types were observed along with genes known to affect insulin release, although with our assay we were not able to detect any effects of 1,25(OH)2D3 on glucose-stimulated insulin release from healthy pancreatic islets. CONCLUSION The effects of 1,25(OH)2D3 on the expression of cytoskeletal and intracellular trafficking genes along with genes involved in ion transport may influence insulin exocytosis. However, an effect of 1,25(OH)2D3 on insulin release could not be detected for healthy islets in contrast to islets subjected to pathological conditions such as cytokine exposure and vitamin D deficiency as suggested by other studies. Thus, in addition to previously identified tolerogenic effects on the immune system, 1,25(OH)2D3 may affect basic functions of pancreatic beta cells, with the potential to render them more resistant to the detrimental conditions encountered during type 1 and 2 diabetes. This article is part of a Special Issue entitled 'Vitamin D Workshop'.
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Affiliation(s)
- H Wolden-Kirk
- Clinical and Experimental Endocrinology, University Hospital Gasthuisberg, Catholic University of Leuven, Herestraat 49, Box 902, B-3000 Leuven, Belgium.
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Chang B, Jin C, Zhang W, Kong L, Yang JH, Lian FM, Li QF, Yu B, Liu WK, Yang LL, Zhao P, Zhen Z. Euonymus alatus in the treatment of diabetic nephropathy in rats. THE AMERICAN JOURNAL OF CHINESE MEDICINE 2013; 40:1177-87. [PMID: 23227790 DOI: 10.1142/s0192415x12500875] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Diabetic nephropathy is a leading cause of chronic renal failure. Recently, Euonymus alatus showed therapeutic potential in the treatment of diabetes and its chronic complications. In this study, effects of Euonymus alatus and its mechanism in the treatment of diabetic nephropathy were investigated. Diabetic nephropathy was induced in Sprague-Dawley rats by uninephrectomy plus streptozotocin (STZ) administration. Euonymus alatus and irbesartan, as a positive control, were lavaged to these rats for 12 weeks. Our data showed that Euonymus alatus was efficient in lowering HbA1c, improving blood lipids, decreasing 24 h urine protein and protecting kidney function. Pathological studies found kidney damage, including extracellular matrix expansion and glomerulosclerosis, were improved by Euonymus alatus treatment. Further investigation found that the herb had a role in downregulating the expression of transform growth factor β(1). In conclusion, Euonymus alatus has a protective role in diabetic nephropathy, which may be related to its downregulation of transform growth factor β(1) expression.
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Affiliation(s)
- Bai Chang
- Key Laboratory of Hormones and Development (Ministry of Health), Metabolic Diseases Hospital and Tianjin Institute of Endocrinology of Tianjin Medical University, Tianjin 300070, China
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Metabolomic analysis of rat serum in streptozotocin-induced diabetes and after treatment with oral triethylenetetramine (TETA). Genome Med 2012; 4:35. [PMID: 22546713 PMCID: PMC3446263 DOI: 10.1186/gm334] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2012] [Revised: 03/29/2012] [Accepted: 04/30/2012] [Indexed: 02/06/2023] Open
Abstract
Background The prevalence, and associated healthcare burden, of diabetes mellitus is increasing worldwide. Mortality and morbidity are associated with diabetic complications in multiple organs and tissues, including the eye, kidney and cardiovascular system, and new therapeutics to treat these complications are required urgently. Triethylenetetramine (TETA) is one such experimental therapeutic that acts to chelate excess copper (II) in diabetic tissues and reduce oxidative stress and cellular damage. Methods Here we have performed two independent metabolomic studies of serum to assess the suitability of the streptozotocin (STZ)-induced rat model for studying diabetes and to define metabolite-related changes associated with TETA treatment. Ultraperformance liquid chromatography-mass spectrometry studies of serum from non-diabetic/untreated, non-diabetic/TETA-treated, STZ-induced diabetic/untreated and STZ-induced diabetic/TETA-treated rats were performed followed by univariate and multivariate analysis of data. Results Multiple metabolic changes related to STZ-induced diabetes, some of which have been reported previously in other animal and human studies, were observed, including changes in amino acid, fatty acid, glycerophospholipid and bile acid metabolism. Correlation analysis suggested that treatment with TETA led to a reversal of diabetes-associated changes in bile acid, fatty acid, steroid, sphingolipid and glycerophospholipid metabolism and proteolysis. Conclusions Metabolomic studies have shown that the STZ-induced rat model of diabetes is an appropriate model system to undertake research into diabetes and potential therapies as several metabolic changes observed in humans and other animal models were also observed in this study. Metabolomics has also identified several biological processes and metabolic pathways implicated in diabetic complications and reversed following treatment with the experimental therapeutic TETA.
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Scott JL, Musselman CA, Adu-Gyamfi E, Kutateladze TG, Stahelin RV. Emerging methodologies to investigate lipid-protein interactions. Integr Biol (Camb) 2012; 4:247-58. [PMID: 22327461 DOI: 10.1039/c2ib00143h] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Cellular membranes are composed of hundreds of different lipids, ion channels, receptors and scaffolding complexes that act as signalling and trafficking platforms for processes fundamental to life. Cellular signalling and membrane trafficking are often regulated by peripheral proteins, which reversibly interact with lipid molecules in highly regulated spatial and temporal fashions. In most cases, one or more modular lipid-binding domain(s) mediate recruitment of peripheral proteins to specific cellular membranes. These domains, of which more than 10 have been identified since 1989, harbour structurally selective lipid-binding sites. Traditional in vitro and in vivo studies have elucidated how these domains coordinate their cognate lipids and thus how the parent proteins associate with membranes. Cellular activities of peripheral proteins and subsequent physiological processes depend upon lipid binding affinities and selectivity. Thus, the development of novel sensitive and quantitative tools is essential in furthering our understanding of the function and regulation of these proteins. As this field expands into new areas such as computational biology, cellular lipid mapping, single molecule imaging, and lipidomics, there is an urgent need to integrate technologies to detail the molecular architecture and mechanisms of lipid signalling. This review surveys emerging cellular and in vitro approaches for studying protein-lipid interactions and provides perspective on how integration of methodologies directs the future development of the field.
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Affiliation(s)
- Jordan L Scott
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
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Ola MS, Nawaz MI, Siddiquei MM, Al-Amro S, Abu El-Asrar AM. Recent advances in understanding the biochemical and molecular mechanism of diabetic retinopathy. J Diabetes Complications 2012; 26:56-64. [PMID: 22226482 DOI: 10.1016/j.jdiacomp.2011.11.004] [Citation(s) in RCA: 125] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Revised: 11/17/2011] [Accepted: 11/17/2011] [Indexed: 02/07/2023]
Abstract
One of the major complications in patients with diabetes is diabetic retinopathy (DR), a leading cause of blindness worldwide. It takes several years before any clinical signs of retinopathy appear in diabetic patients, which gives an ample opportunity for scientists to uncover biochemical and molecular mechanism implicated early in the development and progression of the disease. During the past few decades, research progress has been made in investigating the pathophysiology of the disease; however, due to nonavailability of human retinal samples at different stages of the disease and also due to lack of a proper animal model of DR, the exact molecular mechanism has not been elucidated, making therapeutic a difficult task. In this review article, we have discussed a number of diabetes-induced metabolites such as glucose, lipids, amino acids, and other related factors and molecules that are implicated in the pathophysiology of the DR. Furthermore, we have highlighted neurodegeneration and regulation of neurotrophic factors, being recognized as early events that may be involved in the pathology of the disease in the course of DR. An understanding of the biochemical and molecular changes especially early in the diabetic retina may lead to new and effective therapies towards prevention and amelioration of DR, which is important for the millions of individuals who already have or are likely to develop the disease before a cure becomes available.
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Affiliation(s)
- Mohammad Shamsul Ola
- Department of Ophthalmology, College of Medicine, King Saud University, KAUH, Riyadh, KSA.
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Development of The Dual-labeling Time-resolved Fluoroimmunoassay for Detection of C-peptide and Insulin and Its Initially Application*. PROG BIOCHEM BIOPHYS 2011. [DOI: 10.3724/sp.j.1206.2011.00037] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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O'Neill SM, Yun JK, Fox TE, Kester M. Transcriptional regulation of the human neutral ceramidase gene. Arch Biochem Biophys 2011; 511:21-30. [PMID: 21531200 DOI: 10.1016/j.abb.2011.04.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2010] [Revised: 03/24/2011] [Accepted: 04/18/2011] [Indexed: 12/28/2022]
Abstract
Ceramidases play a critical role in generating sphingosine-1-phosphate by hydrolyzing ceramide into sphingosine, a substrate for sphingosine kinase. In order to elucidate its transcriptional regulation, we identify here a putative promoter region in the 5'-UTR of the human neutral CDase (nCDase) gene. Using human genomic DNA, we cloned a 3000 bp region upstream of the translational start site of the nCDase gene. Luciferase reporter analyses demonstrated that this 3000 bp region had promoter activity, with the strongest induction occurring within the first 200 bp. Computational analysis revealed the 200 bp essential promoter region contained several well-characterized promoter elements, lacked a conical TATA box, but did contain a reverse oriented CCAAT box, a feature common to housekeeping genes. Electrophoretic mobility shift assays demonstrated that the identified candidate transcriptional response elements (TRE) bind their respective transcription factors, including NF-Y, AP-2, Oct-1, and GATA. Mutagenic analyses of the TRE revealed that these sites regulated promoter activity and mutating an individual site decreased promoter reporter activity by up to 50%. Together, our findings suggest that regulation of nCDase expression involves coordinated TATA-less transcriptional activity.
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Affiliation(s)
- Sean M O'Neill
- Department of Pharmacology, Penn State College of Medicine, Hershey, PA 17033, USA
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Abstract
In recent years, the study of lipid signalling networks has significantly increased. Although best studied in mammalian cells, lipid signalling is now appreciated also in microbial cells, particularly in yeasts and moulds. For instance, microbial sphingolipids and their metabolizing enzymes play a key role in the regulation of fungal pathogenicity, especially in Cryptococcus neoformans, through the modulation of different microbial pathways and virulence factors. Another example is the quorum sensing molecule (QSM) farnesol. In fact, this QSM is involved not only in mycelial growth and biofilm formation of Candida albicans, but also in many stress related responses. In moulds, such as Aspergillus fumigatus, QSM and sphingolipids are important for maintaining cell wall integrity and virulence. Finally, fungal cells make oxylipins to increase their virulence attributes and to counteract the host immune defences. In this review, we discuss these aspects in details.
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Affiliation(s)
- Arpita Singh
- Biochemistry and Molecular Biology Microbiology and Immunology Division of Infectious Diseases, Medical University of South Carolina, Charleston, SC 29425, USA
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Fox TE, Bewley MC, Unrath KA, Pedersen MM, Anderson RE, Jung DY, Jefferson LS, Kim JK, Bronson SK, Flanagan JM, Kester M. Circulating sphingolipid biomarkers in models of type 1 diabetes. J Lipid Res 2010; 52:509-17. [PMID: 21068007 DOI: 10.1194/jlr.m010595] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Alterations in lipid metabolism may contribute to diabetic complications. Sphingolipids are essential components of cell membranes and have essential roles in homeostasis and in the initiation and progression of disease. However, the role of sphingolipids in type 1 diabetes remains largely unexplored. Therefore, we sought to quantify sphingolipid metabolites by LC-MS/MS from two animal models of type 1 diabetes (streptozotocin-induced diabetic rats and Ins2(Akita) diabetic mice) to identify putative therapeutic targets and biomarkers. The results reveal that sphingosine-1-phosphate (So1P) is elevated in both diabetic models in comparison to respective control animals. In addition, diabetic animals demonstrated reductions in plasma levels of omega-9 24:1 (nervonic acid)-containing ceramide, sphingomyelin, and cerebrosides. Reduction of 24:1-esterfied sphingolipids was also observed in liver and heart. Nutritional stress via a high-fat diet also reduced 24:1 content in the plasma and liver of mice, exacerbating the decrease in some cases where diabetes was also present. Subcutaneous insulin corrected both circulating So1P and 24:1 levels in the murine diabetic model. Thus, changes in circulating sphingolipids, as evidenced by an increase in bioactive So1P and a reduction in cardio- and neuro-protective omega-9 esterified sphingolipids, may serve as biomarkers for type 1 diabetes and represent novel therapeutic targets.
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Affiliation(s)
- Todd E Fox
- Department of Pharmacology, Penn State College of Medicine, Milton S. Hershey Medical Center, Hershey, PA, USA
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