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Madhavan A, Kushwaha D, Nath D, Ghosh Moulick R, Bhattacharya J. Natural Occurrence of Carbon Dots during In Vitro Nonenzymatic Glycosylation of Hemoglobin A0. ACS OMEGA 2022; 7:3881-3888. [PMID: 35155885 PMCID: PMC8829870 DOI: 10.1021/acsomega.1c03219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Accepted: 08/23/2021] [Indexed: 06/14/2023]
Abstract
Carbon dots, the nanostructures of carbon, have excellent optical and chemical properties and find a range of applications in various fields of biology and medicine. In the current study, carbon dots are synthesized using in vitro nonenzymatic glycosylation at 37 °C, which is the conventional method for the synthesis of Advanced Glycosylation End products. While comparing the physicochemical properties using a series of physical and chemical analyses including light absorption, fluorescence, photoluminescence, chemical composition, functional group analysis, and in vitro imaging, striking similarities are found among Carbon dots and Advanced Glycosylation End products. Based on the evident resemblance between the two, we propose either the presence of a common structural backbone or the coexistence of the two individual chemical entities. Thus, the formation of carbon dots at physiological temperatures raises health concerns as nonenzymatic glycosylation is a physiological process in humans and the rate of which is elevated during diabetes. The Advanced Glycosylation End products are known to have a detrimental effect in diabetic patients, and the chemical similarity between the two questions the widely studied biocompatibility of carbon dots.
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Affiliation(s)
- Ashwathi
Asha Madhavan
- School
of Biotechnology, Jawaharlal Nehru University, New Mehrauli Road, New Delhi 110067, India
| | - Deepak Kushwaha
- School
of Biotechnology, Jawaharlal Nehru University, New Mehrauli Road, New Delhi 110067, India
- Amity
Institute of Integrative Sciences and Health, Amity University Gurgaon, Haryana 122413, India
| | - Debasish Nath
- School
of Biotechnology, Jawaharlal Nehru University, New Mehrauli Road, New Delhi 110067, India
| | - Ranjita Ghosh Moulick
- Amity
Institute of Integrative Sciences and Health, Amity University Gurgaon, Haryana 122413, India
| | - Jaydeep Bhattacharya
- School
of Biotechnology, Jawaharlal Nehru University, New Mehrauli Road, New Delhi 110067, India
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2
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Martinez Fernandez A, Regazzoni L, Brioschi M, Gianazza E, Agostoni P, Aldini G, Banfi C. Pro-oxidant and pro-inflammatory effects of glycated albumin on cardiomyocytes. Free Radic Biol Med 2019; 144:245-255. [PMID: 31260731 DOI: 10.1016/j.freeradbiomed.2019.06.023] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 06/13/2019] [Accepted: 06/19/2019] [Indexed: 12/14/2022]
Abstract
Human serum albumin (HSA) is the most abundant circulating protein in the body and presents an extensive range of biological functions. As such, it is prone to undergo post-translational modifications (PTMs). The non-enzymatic early glycation of HSA, one of the several PTMs undergone by HSA, arises from the addition of reducing sugars to amine group residues, thus modifying the structure of HSA. These changes may affect HSA functions impairing its biological activity, finally leading to cell damage. The aim of this study was to quantitate glycated-HSA (GA) levels in the plasma of heart failure (HF) patients and to evaluate the biological effects of GA on HL-1 cardiomyocytes. Plasma GA content from HF patients and healthy subjects was measured by direct infusion electrospray ionization mass spectrometry (ESI-MS). Results pointed out a significant increase of GA in HF patients with respect to the control group (p < 0.05). Additionally, after stimulation with GA, proteomic analysis of HL-1 secreted proteins showed the modulation of several proteins involved, among other processes, in the response to stress. Further, stimulated cells showed a rapid increase in ROS generation, higher mRNA levels of the inflammatory cytokine interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α), and higher levels of the oxidative 4-HNE-protein adducts and carbonylated proteins. Our findings show that plasma GA is increased in HF patients. Further, GA exerts pro-inflammatory and pro-oxidant effects on cardiomyocytes, which suggest a causal role in the etiopathogenesis of HF.
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MESH Headings
- Aged
- Case-Control Studies
- Cell Death
- Cell Line
- Dyslipidemias/blood
- Dyslipidemias/genetics
- Dyslipidemias/pathology
- Female
- Gene Expression Profiling
- Gene Ontology
- Glycation End Products, Advanced
- Glycosylation
- HSP90 Heat-Shock Proteins/genetics
- HSP90 Heat-Shock Proteins/metabolism
- Heart Failure/blood
- Heart Failure/genetics
- Heart Failure/pathology
- Humans
- Hypertension/blood
- Hypertension/genetics
- Hypertension/pathology
- Interleukin-6/genetics
- Interleukin-6/metabolism
- Lysine/analogs & derivatives
- Lysine/blood
- Male
- Middle Aged
- Molecular Sequence Annotation
- Myocardium/metabolism
- Myocardium/pathology
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- Natriuretic Peptide, Brain/blood
- Natriuretic Peptide, Brain/genetics
- Protein Carbonylation
- Protein Processing, Post-Translational
- Reactive Oxygen Species/agonists
- Reactive Oxygen Species/metabolism
- Serum Albumin/pharmacology
- Serum Albumin, Human/chemistry
- Serum Albumin, Human/genetics
- Serum Albumin, Human/metabolism
- Tumor Necrosis Factor-alpha/genetics
- Tumor Necrosis Factor-alpha/metabolism
- Glycated Serum Albumin
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Affiliation(s)
| | - Luca Regazzoni
- Department of Pharmaceutical Sciences, University of Milan, Milan, Italy
| | | | | | - Piergiuseppe Agostoni
- Centro Cardiologico Monzino, IRCCS, Milan, Italy; Department of Clinical Sciences and Community Health, Cardiovascular Section, University of Milan, Milan, Italy
| | - Giancarlo Aldini
- Department of Pharmaceutical Sciences, University of Milan, Milan, Italy
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3
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May JM. Ascorbic acid repletion: A possible therapy for diabetic macular edema? Free Radic Biol Med 2016; 94:47-54. [PMID: 26898503 PMCID: PMC4844774 DOI: 10.1016/j.freeradbiomed.2016.02.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 02/10/2016] [Accepted: 02/16/2016] [Indexed: 02/07/2023]
Abstract
Macular edema poses a significant risk for visual loss in persons with diabetic retinopathy. It occurs when plasma constituents and fluid leak out of damaged retinal microvasculature in the area of the macula, causing loss of central vision. Apoptotic loss of pericytes surrounding capillaries is perhaps the earliest feature of diabetic vascular damage in the macula, which is also associated with dysfunction of the endothelium and loss of the otherwise very tight endothelial permeability barrier. Increased oxidative stress is a key feature of damage to both cell types, mediated by excess superoxide from glucose-induced increases in mitochondrial metabolism, as well as by activation of the receptor for advanced glycation end products (RAGE). The latter in turn activates multiple pathways, some of which lead to increased oxidative stress, such as those involving NF-ĸB, NADPH oxidase, and endothelial nitric oxide synthase. Such cellular oxidative stress is associated with low cellular and plasma ascorbic acid levels in many subjects with diabetes in poor glycemic control. Whether repletion of low ascorbate in retinal endothelium and pericytes might help to prevent diabetic macular edema is unknown. However, cell culture studies show that the vitamin prevents high-glucose and RAGE-induced apoptosis in both cell types, that it preserves nitric oxide generated by endothelial cells, and that it tightens the leaky endothelial permeability barrier. Although these findings need to be confirmed in pre-clinical animal studies, it is worth considering clinical trials to determine whether adequate ascorbate repletion is possible and whether it might help to delay or even reverse early diabetic macular edema.
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Affiliation(s)
- James M May
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232-6303, United States.
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4
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Ascorbic acid prevents high glucose-induced apoptosis in human brain pericytes. Biochem Biophys Res Commun 2014; 452:112-7. [PMID: 25152398 DOI: 10.1016/j.bbrc.2014.08.057] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 08/13/2014] [Indexed: 02/07/2023]
Abstract
High glucose concentrations due to diabetes increase apoptosis of vascular pericytes, impairing vascular regulation and weakening vessels, especially in brain and retina. We sought to determine whether vitamin C, or ascorbic acid, could prevent such high glucose-induced increases in pericyte apoptosis. Culture of human microvascular brain pericytes at 25 mM compared to 5mM glucose increased apoptosis measured as the appearance of cleaved caspase 3. Loading the cells with ascorbate during culture decreased apoptosis, both at 5 and 25 mM glucose. High glucose-induced apoptosis was due largely to activation of the receptor for advanced glycation end products (RAGE), since it was prevented by specific RAGE inhibition. Culture of pericytes for 24h with RAGE agonists also increased apoptosis, which was completely prevented by inclusion of 100 μM ascorbate. Ascorbate also prevented RAGE agonist-induced apoptosis measured as annexin V binding in human retinal pericytes, a cell type with relevance to diabetic retinopathy. RAGE agonists decreased intracellular ascorbate and GSH in brain pericytes. Despite this evidence of increased oxidative stress, ascorbate prevention of RAGE-induced apoptosis was not mimicked by several antioxidants. These results show that ascorbate prevents pericyte apoptosis due RAGE activation. Although RAGE activation decreases intracellular ascorbate and GSH, the prevention of apoptosis by ascorbate may involve effects beyond its function as an antioxidant.
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Cohen MP. Clinical, pathophysiological and structure/function consequences of modification of albumin by Amadori-glucose adducts. Biochim Biophys Acta Gen Subj 2013; 1830:5480-5. [PMID: 23624335 DOI: 10.1016/j.bbagen.2013.04.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 04/16/2013] [Accepted: 04/17/2013] [Indexed: 11/25/2022]
Abstract
BACKGROUND The nonenzymatic condensation of glucose with albumin results in the formation of albumin modified by Amadori glucose adducts, the principal form in which glycated albumin exists in vivo. SCOPE OF REVIEW This review focuses on (a) the utility of measurement of Amadori-modified glycated albumin (AGA) as a biomarker in diabetes, where elevated levels attend the hyperglycemic state; (b) the role of AGA as a causal factor in the pathogenesis of complications of diabetes; (c) effects on transport properties; and (d) structural and functional consequences of the modification of albumin by Amadori glucose adducts. It does not discuss counterparts with respect to Advanced Glycation Endproducts (AGE), which may be found in other publications. MAJOR CONCLUSIONS Nonenzymatic glycation of albumin, which is increased in diabetes, has clinical relevance and pathophysiologic importance, with ramifications for the management of this disease, the development of its complications, and the transport of endogenous and exogenous ligands. GENERAL SIGNIFICANCE Appreciation of the manifold consequences of AGA has afforded new avenues for assessing clinical management of diabetes, awareness of the impact of nonenzymatic glycation on albumin biology, insights into the pathogenesis of vascular complications of diabetes, and avenues of investigation of and intervention strategies for these complications. This article is part of a Special Issue on albumin. This article is part of a Special Issue entitled Serum Albumin.
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Affiliation(s)
- Margo P Cohen
- Glycadia, Inc., 1880 JFK Boulevard, Suite 200, Philadelphia, PA 19103, United States.
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6
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Kim JB, Lee SH, Ahn J, Kim J. The Peroxisome Proliferator-Activated Receptor δ Agonist, GW501516, Inhibits Angiogenesis through Dephosphorylation of Endothelial Nitric Oxide Synthase. J Lipid Atheroscler 2012. [DOI: 10.12997/jla.2012.1.1.11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Jae-Bok Kim
- Department of Pediatrics, Seoul Metropolitan Children's Hospital, Seoul, Korea
| | - Seok Hong Lee
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Chung-Ang University, Seoul, Korea
| | - Jihyun Ahn
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Chung-Ang University, Seoul, Korea
| | - Jaetaek Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Chung-Ang University, Seoul, Korea
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Liu W, Xu GZ, Jiang CH, Tian J. Macrophage colony-stimulating factor and its receptor signaling augment glycated albumin-induced retinal microglial inflammation in vitro. BMC Cell Biol 2011; 12:5. [PMID: 21266043 PMCID: PMC3038972 DOI: 10.1186/1471-2121-12-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Accepted: 01/25/2011] [Indexed: 01/30/2023] Open
Abstract
Background Microglial activation and the proinflammatory response are controlled by a complex regulatory network. Among the various candidates, macrophage colony-stimulating factor (M-CSF) is considered an important cytokine. The up-regulation of M-CSF and its receptor CSF-1R has been reported in brain disease, as well as in diabetic complications; however, the mechanism is unclear. An elevated level of glycated albumin (GA) is a characteristic of diabetes; thus, it may be involved in monocyte/macrophage-associated diabetic complications. Results The basal level of expression of M-CSF/CSF-1R was examined in retinal microglial cells in vitro. Immunofluorescence, real-time PCR, immunoprecipitation, and Western blot analyses revealed the up-regulation of CSF-1R in GA-treated microglial cells. We also detected increased expression and release of M-CSF, suggesting that the cytokine is produced by activated microglia via autocrine signaling. Using an enzyme-linked immunosorbent assay, we found that GA affects microglial activation by stimulating the release of tumor necrosis factor-α and interleukin-1β. Furthermore, the neutralization of M-CSF or CSF-1R with antibodies suppressed the proinflammatory response. Conversely, this proinflammatory response was augmented by the administration of M-CSF. Conclusions We conclude that GA induces microglial activation via the release of proinflammatory cytokines, which may contribute to the inflammatory pathogenesis of diabetic retinopathy. The increased microglial expression of M-CSF/CSF-1R not only is a response to microglial activation in diabetic retinopathy but also augments the microglial inflammation responsible for the diabetic microenvironment.
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Affiliation(s)
- Wei Liu
- Department of Opthalmology, EENT Hospital, Eye Institute, Fudan University, Shanghai, 200031, China
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8
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Adachi T, Aida K, Nishihara H, Kamiya T, Hara H. Effect of Hypoxia Mimetic Cobalt Chloride on the Expression of Extracellular-Superoxide Dismutase in Retinal Pericytes. Biol Pharm Bull 2011; 34:1297-300. [DOI: 10.1248/bpb.34.1297] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Tetsuo Adachi
- Laboratory of Clinical Pharmaceutics, Gifu Pharmaceutical University
| | - Kazunari Aida
- Laboratory of Clinical Pharmaceutics, Gifu Pharmaceutical University
| | - Hiroko Nishihara
- Laboratory of Clinical Pharmaceutics, Gifu Pharmaceutical University
| | - Tetsuro Kamiya
- Laboratory of Clinical Pharmaceutics, Gifu Pharmaceutical University
| | - Hirokazu Hara
- Laboratory of Clinical Pharmaceutics, Gifu Pharmaceutical University
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9
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Rodiño-Janeiro BK, González-Peteiro M, Ucieda-Somoza R, González-Juanatey JR, Alvarez E. Glycated albumin, a precursor of advanced glycation end-products, up-regulates NADPH oxidase and enhances oxidative stress in human endothelial cells: molecular correlate of diabetic vasculopathy. Diabetes Metab Res Rev 2010; 26:550-8. [PMID: 20818804 DOI: 10.1002/dmrr.1117] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
BACKGROUND Hyperglycaemia induces non-enzymatic glycation reactions in proteins which generate Amadori products and advanced glycation end-products; the latter are thought to participate in the vascular complications of diabetic patients. However, the exact mechanisms concerning the effects of glycated proteins on vascular tissue remain to be determined. Therefore, the effects of glycated human serum albumin on human umbilical vein endothelial cells were studied. METHODS Reactive oxygen species production was measured by the cytochrome C reduction method and by 5(6)-carboxy-2',7'-dichlorofluorescein diacetate (c-DCF-DA) fluorescence after treating human umbilical vein endothelial cells with glycated human serum albumin (6-200 µg/mL). The expression of Nox4 and p22phox mRNAs were analysed by reverse transcription-quantitative polymerase chain reactions and the levels of their proteins were measured by immunofluorescence. RESULTS Low concentrations of glycated human serum albumin enhanced reactive oxygen species production in human umbilical vein endothelial cells after 4 h of treatment at both extracellular and intracellular sites. This enhanced production was sustained, although to a lesser extent, after 6 and 12 h of treatment. The gene expression study revealed that Nox4 and p22phox mRNA levels were elevated after 4 h of treatment with glycated human serum albumin. This mRNA elevation and enhanced reactive oxygen species production correlated with an increased expression of the Nox4 protein. CONCLUSIONS The results revealed that a circulating and abundant modified glycated human serum albumin protein in diabetic patients induced a sustained reactive oxygen species production in human endothelial cells. This effect may have been due to an up-regulation of Nox4, the main subunit of NADPH oxidase in the endothelium.
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Affiliation(s)
- Bruno K Rodiño-Janeiro
- Departamento de Medicina, Universidad de Santiago de Compostela and Servicio de Cardiología, Complejo Hospitalario Universitario de Santiago de Compostela, Coruña, Spain
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10
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Geraldes P, Yagi K, Ohshiro Y, He Z, Maeno Y, Yamamoto-Hiraoka J, Rask-Madsen C, Chung SW, Perrella MA, King GL. Selective regulation of heme oxygenase-1 expression and function by insulin through IRS1/phosphoinositide 3-kinase/Akt-2 pathway. J Biol Chem 2008; 283:34327-36. [PMID: 18854316 PMCID: PMC2590690 DOI: 10.1074/jbc.m807036200] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Revised: 10/08/2008] [Indexed: 02/01/2023] Open
Abstract
Heme oxygenase 1 (HO-1) is a representative mediator of antioxidants and cytoprotectants against various stress stimuli including oxidants in vascular cells. Intensive insulin treatment can delay the onset and progression of diabetic retinopathy and other vascularopathies, yet little is known about insulin regulation of anti-apoptotic and antioxidant molecules such as HO-1 in vascular cells. Intravitreous injection or in vitro addition of insulin increased HO-1 protein expression in rat retina and in cultured bovine retinal pericytes, retinal endothelial cells, and retinal pigment epithelial cells. In bovine retinal pericytes, insulin induced mRNA and protein expression of HO-1 in a time- and concentration-dependent manner. Using HO-1 promoter analysis, the luciferase reporter assay showed that induction of HO-1 expression by insulin is mediated by additional response elements in the ho-1 promoter gene, which was not responsive to antioxidants. Insulin-induced HO-1 mRNA expression through activation of PI3-kinase/Akt pathway without affecting ERK and p38 MAPK. Overexpression of an adenoviral vector of native IRS1, IRS2, and Akt dominant negative or small interfering RNA transfection of Akt1 and Akt2 targeted gene demonstrated that insulin regulated HO-1 expression via IRS1 and Akt2 pathway, selectively. Further, insulin treatment prevented H(2)O(2)-induced NF-kappaB and caspase-8 activation and apoptosis via the IRS1/PI3K/Akt2/HO-1 pathway in the pericytes. In conclusion, we suggest that the anti-apoptotic properties of insulin are mediated partly by increasing HO-1 expression at transcriptional level via IRS1/PI3K/Akt2 activation, a potential explanation for how insulin is retarding the progression of microvascular complications induced by diabetes.
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Affiliation(s)
- Pedro Geraldes
- Research Division, Joslin Diabetes Center, Boston, MA 02215, USA
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11
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Li L, Renier G. Activation of nicotinamide adenine dinucleotide phosphate (reduced form) oxidase by advanced glycation end products links oxidative stress to altered retinal vascular endothelial growth factor expression. Metabolism 2006; 55:1516-23. [PMID: 17046555 DOI: 10.1016/j.metabol.2006.06.022] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2006] [Accepted: 06/15/2006] [Indexed: 11/28/2022]
Abstract
Increasing evidence indicates that advanced glycation end products (AGEs) promote retinal alterations through oxidative stress. However, the pathways involved in AGE-induced generation of reactive oxygen species (ROS) in retinal cells are poorly defined. In the present study, we investigated the role of nicotinamide adenine dinucleotide phosphate (reduced form) (NADPH) oxidase in AGE-induced ROS intracellular generation and vascular endothelial growth factor (VEGF) expression in bovine retinal endothelial cells (BRECs). Incubation of BRECs with 100 microg/mL AGEs increased ROS generation and VEGF expression in these cells. Treatment of the cells with the NADPH oxidase inhibitors, apocynin and diphenylene iodonium, inhibited these effects. In retinal endothelial cells exposed to AGEs, translocation of protein kinase C (PKC)-beta2 and p47phox was observed. Inhibition of PKC by treatment of the cells with calphostin C, GF10923X, and LY379196 totally suppressed AGE-mediated p47phox translocation and ROS generation. Incubation of BRECs with gliclazide inhibited AGE-induced PKC-beta2 and p47phox translocation and totally abrogated AGE-mediated ROS generation and VEGF expression. Overall, these results demonstrate that AGEs induce intracellular ROS generation and VEGF expression in retinal endothelial cells through a PKC-dependent activation of NADPH oxidase. Inhibition of retinal NADPH oxidase expression and ROS generated by this system provides a new potential mechanism by which gliclazide may affect retinal VEGF expression and exert a beneficial effect on diabetic retinopathy.
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Affiliation(s)
- Ling Li
- CHUM Research Centre, Vascular Immunology Laboratory, Notre-Dame Hospital, Department of Medicine, University of Montreal, Quebec, Canada H2L 4M1
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12
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Edelman DA, Jiang Y, Tyburski J, Wilson RF, Steffes C. Pericytes and their role in microvasculature homeostasis. J Surg Res 2006; 135:305-11. [PMID: 16930620 DOI: 10.1016/j.jss.2006.06.010] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2005] [Revised: 05/18/2006] [Accepted: 06/15/2006] [Indexed: 11/20/2022]
Abstract
BACKGROUND The microvascular pericyte was first described in 1873, though it is a cell that has largely been ignored in the clinical literature. Pericytes are multifunctional, polymorphic, perivascular cells that lie within, and contribute to the production of the microvessel basil lamina. MATERIALS The pericyte is the second cell that comprises the capillary wall, and is in a prime location to be involved with microvascular permeability. The exact sequence of events in Acute Respiratory Distress Syndrome (ARDS) is unknown, though increased permeability (pulmonary edema) is the primary physiological abnormality seen in the early stages. Pericytes are crucial in the development of capillary leak and pulmonary edema seen in ARDS. Pericytes regulate permeability through contractility and apoptosis. RESULTS Changes in pericyte contractility alter the physical capillary barrier by opening the endothelial junctional space, and are reversible. Pericyte apoptosis leads to a compromise of the barrier effect of the capillary wall, and is a more permanent change. CONCLUSIONS The purpose of this paper is to review publications of pericyte physiological and pathophysiologic interactions in regards to contractility, apoptosis, and permeability.
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Affiliation(s)
- David A Edelman
- Department of Surgery, Wayne State University, Detroit, Michigan 48201, USA
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13
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Cui Y, Xu X, Bi H, Zhu Q, Wu J, Xia X, Ho PCP. Expression modification of uncoupling proteins and MnSOD in retinal endothelial cells and pericytes induced by high glucose: the role of reactive oxygen species in diabetic retinopathy. Exp Eye Res 2006; 83:807-16. [PMID: 16750827 DOI: 10.1016/j.exer.2006.03.024] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2005] [Accepted: 03/31/2006] [Indexed: 11/17/2022]
Abstract
Uncoupling proteins (UCPs) are mitochondrial transporters present in the inner membrane of mitochondria. They belong to the family of anion mitochondrial carriers. UCPs could act as proton carriers activated by metabolites and create a shunt between complexes of the respiratory chain and ATP synthase. The increased leakiness of the mitochondrial inner membrane to protons may be to minimize superoxide production by limiting the maximum Deltamu(H+). The purpose of this study was to detect UCP expression in retinal capillary cells and their modification in high levels of glucose. The role of reactive oxygen species (ROS) of mitochondria and UCPs in pathogenesis of diabetic retinopathy was investigated. Bovine retinal capillary endothelial cells and pericytes were cultured with selective culture media, respectively. Passage cells were cultured in three different glucose concentrations (5, 23, 30 mM) until passage four. ROS changes in mitochondria of these cells in different glucose concentrations were detected with scanning laser confocal microscopy (SLCM). The mitochondria membrane potential (Deltapsi), cell death rate and apoptosis rate were measured with flowing cytometry. UCP expression in retinal capillary cells was detected by immunocytochemistry. Expression and modification of MnSOD and uncoupling proteins (UCPs) in different concentrations of glucose were detected by means of semi-quantitative RT-PCR. ROS in mitochondria of both endothelial cells and pericytes increased as the glucose concentration of media increased. Deltapsi and cell death rate of endothelial cells increased also. ROS was correlated to Deltapsi and cell death rate positively in endothelial cells. No difference in Deltapsi and cell death rate among different glucose levels was found in pericytes. Apoptosis rate of endothelial cells and pericytes in high glucose levels was higher than that in lower glucose levels. UCP1 and UCP2 were expressed in cultured retinal capillary cells whereas UCP3 was not. At high levels of glucose, expression of UCP1, UCP2 and MnSOD increased to accommodate ROS production compensatively. The compensative mechanism disappeared when glucose concentration was too high (30 mM). The results of this study showed that increasing mitochondrial ROS could be induced by high glucose concentration. Those proteins related to antioxidation mechanism, such as MnSOD and UCPs, could exert compensative action to a certain extent. This compensative action was insufficient when the glucose concentration was too high.
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Affiliation(s)
- Yan Cui
- Department of Ophthalmology, Shanghai First People's Hospital, 85 Wu Jin Road, Shanghai 200080, PR China
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14
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Riboulet-Chavey A, Pierron A, Durand I, Murdaca J, Giudicelli J, Van Obberghen E. Methylglyoxal impairs the insulin signaling pathways independently of the formation of intracellular reactive oxygen species. Diabetes 2006; 55:1289-99. [PMID: 16644685 DOI: 10.2337/db05-0857] [Citation(s) in RCA: 162] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Nonenzymatic glycation is increased in diabetes and leads to elevated levels of advanced glycation end products (AGEs), which link hyperglycemia to the induction of insulin resistance. In hyperglycemic conditions, intracellularly formed alpha-ketoaldehydes, such as methylglyoxal, are an essential source of intracellular AGEs, and the abnormal accumulation of methylglyoxal is related to the development of diabetes complications in various tissues and organs. We have previously shown in skeletal muscle that AGEs induce insulin resistance at the level of metabolic responses. Therefore, it was important to extend our work to intermediates of the biosynthetic pathway leading to AGEs. Hence, we asked the question whether the reactive alpha-ketoaldehyde methylglyoxal has deleterious effects on insulin action similar to AGEs. We analyzed the impact of methylglyoxal on insulin-induced signaling in L6 muscle cells. We demonstrate that a short exposure to methylglyoxal induces an inhibition of insulin-stimulated phosphorylation of protein kinase B and extracellular-regulated kinase 1/2, without affecting insulin receptor tyrosine phosphorylation. Importantly, these deleterious effects of methylglyoxal are independent of reactive oxygen species produced by methylglyoxal but appear to be the direct consequence of an impairment of insulin-induced insulin receptor substrate-1 tyrosine phosphorylation subsequent to the binding of methylglyoxal to these proteins. Our data suggest that an increase in intracellular methylglyoxal content hampers a key molecule, thereby leading to inhibition of insulin-induced signaling. By such a mechanism, methylglyoxal may not only induce the debilitating complications of diabetes but may also contribute to the pathophysiology of diabetes in general.
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Zhang YX, Wang YY, Lee WH, Zheng YT, Zhang Y. Apoptotic activity of frog Bombina maxima skin albumin. Comp Biochem Physiol B Biochem Mol Biol 2005; 143:153-9. [PMID: 16343964 DOI: 10.1016/j.cbpb.2005.11.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2005] [Revised: 11/05/2005] [Accepted: 11/06/2005] [Indexed: 11/19/2022]
Abstract
Albumin, the most abundant protein components of blood plasma, is synthesized and secreted by liver cells in vertebrates. Recently, it was demonstrated that frog Bombina maxima albumin is also expressed in skin. Both B. maxima albumins from skin and serum (BmA-skin and BmA-serum) have similar biochemical characteristics except that the former contains haem b. Present studies showed that BmA-skin exhibited cytotoxic activity on H9 and C8166 cells. Pretreated with hemin to induce erythroid differentiation, K562 cells lost their resistance to cytotoxicity of BmA-skin. After treating cells with BmA-skin for 48 h, 50 percentage cytotoxic concentrations (CC(50)) of BmA-skin on H9, C8166 and hemin-treated K562 cells were 1.31+/-0.09, 1.59+/-0.08 and 2.28+/-0.06 microM, respectively. The cell death induced by BmA-skin was mediated by apoptosis of the tested cell lines, as demonstrated by nuclear morphological changes, DNA fragmentation and DNA hypodiploidy of apoptosis cells. At BmA-skin concentration of 2 microM, 27.3%, 19.7% and 17.8% of H9, C8166 and hemin-treated K562 cells were found to be apoptotic. In contrast, BmA-serum possessed no cytotoxic and apoptosis-inducing activity on all the cell lines tested, even with concentration used up to 15 microM. These results indicated that bound haem b in BmA-skin contributed significantly to its cytotoxic and apoptosis-inducing activity on the cell lines assayed.
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Affiliation(s)
- Ying-Xia Zhang
- Department of Animal Toxinology, Kunming Institute of Zoology, The Chinese Academy of Sciences, 32 East Jiao Chang Road, Kunming, Yunnan 650223, China.
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16
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Kim J, Oh YS, Shinn SH. Troglitazone reverses the inhibition of nitric oxide production by high glucose in cultured bovine retinal pericytes. Exp Eye Res 2005; 81:65-70. [PMID: 15978256 DOI: 10.1016/j.exer.2005.01.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2004] [Revised: 01/12/2005] [Accepted: 01/16/2005] [Indexed: 12/01/2022]
Abstract
In the retinal microcirculation, there is a basal release of nitric oxide (NO) which maintains the retinal blood flow. The proportions of endothelial cells and pericytes in the retinal capillaries are almost equal, so pericytes appear to play a important role in the regulation of microcirculatory hemodynamics in the retina. It has been suggested that the pathogenesis of early diabetic retinopathy may involve a reduced bioavailability or diminished production of NO. In this study, we investigated the role of troglitazone, a potent agonist of peroxisome proliferator activated receptor-gamma (PPARgamma) used for the treatment of diabetes, on the NO release and the effect of exposure to high glucose on the production of NO in cultured bovine retinal pericytes. Troglitazone significantly increased NO production and iNOS expression after 24hr in a dose-and PPARgamma-dependent manner. Elevation of D-glucose, but not L-glucose, from 5.5 to 30 mm for 24 hr decreased NO production, but co-treatment with troglitazone reversed high glucose-induced inhibition of NO production as well as iNOS expression. In conclusion, high glucose inhibits iNOS expression and subsequently NO synthesis in cultured bovine retinal pericytes, and troglitazone restores the NO production.
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Affiliation(s)
- Jaetaek Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Chung-Ang University, Seoul, South Korea.
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17
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Kowluru RA. Effect of advanced glycation end products on accelerated apoptosis of retinal capillary cells under in vitro conditions. Life Sci 2005; 76:1051-60. [PMID: 15607333 DOI: 10.1016/j.lfs.2004.10.017] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2004] [Accepted: 10/02/2004] [Indexed: 01/01/2023]
Abstract
Advanced glycation end-products (AGEs) are considered to play an important role in the development of retinopathy in diabetes, and are shown to induce retinal vascular changes resembling that of diabetic retinopathy. We have shown that apoptosis of retinal capillary cells is accelerated in diabetes. The aim of this study is to investigate the role of AGEs in accelerated retinal capillary cell death in in vitro conditions, and to identify the possible mechanism involved. Bovine retinal endothelial cells and pericytes were incubated in the presence of 5 microM AGE-bovine serum albumin (AGE-BSA) or untreated control BSA (BSA) for up to five days. The cell death was determined by performing ELISA for cytoplasmic histone-associated DNA fragments and by measuring the activity of caspase-3. Incubation of endothelial cells or pericytes with AGE-BSA increased oxidative stress and NO by 60%, and in the same cells nuclear transcriptional factor (NF-kB) was also activated by over 60%. AGE-BSA induced their apoptosis by 55%, and activated caspase-3 by about 50% compared to the cells incubated with unmodified BSA. Co-addition of AGE-BSA and antioxidants (N-acetyl cysteine or alpha-lipoic acid) inhibited oxidative stress, nitrotyrosine formation, NF-kB activation and capillary cell apoptosis. These data strongly suggest that increased AGE in diabetes could play an important role in retinal capillary apoptosis and that oxidative stress is involved in this process. Inhibition of AGEs in the retinal capillary cells could prevent their apoptosis, and ultimately, the development of retinopathy in diabetes.
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Affiliation(s)
- Renu A Kowluru
- Kresge Eye Institute, Wayne State University, Detroit, MI 48201, USA
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Kim J, Son JW, Lee JA, Oh YS, Shinn SH. Methylglyoxal induces apoptosis mediated by reactive oxygen species in bovine retinal pericytes. J Korean Med Sci 2004; 19:95-100. [PMID: 14966349 PMCID: PMC2822272 DOI: 10.3346/jkms.2004.19.1.95] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
One of the histopathologic hallmarks of early diabetic retinopathy is the loss of pericytes. Evidences suggest that the pericyte loss in vivo is mediated by apoptosis. However, the underlying cause of pericyte apoptosis is not fully understood. This study investigated the influence of methylglyoxal (MGO), a reactive alpha-dicarbonyl compound of glucose metabolism, on apoptotic cell death in bovine retinal pericytes. Analysis of internucleosomal DNA fragmentation by ELISA showed that MGO (200 to 800 microM) induced apoptosis in a concentration-dependent manner. Intracellular reactive oxygen species were generated earlier and the antioxidant, N-acetyl cysteine, inhibited the MGO-induced apoptosis. NF-kappaB activation and increased caspase-3 activity were detected. Apoptosis was also inhibited by the caspase-3 inhibitor, Z-DEVD-fmk, or the NF-kappaB inhibitor, pyrrolidine dithiocarbamate. These data suggest that elevated MGO levels observed in diabetes may cause apoptosis in bovine retinal pericytes through an oxidative stress mechanism and suggests that the nuclear activation of NF-kappaB are involved in the apoptotic process.
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Affiliation(s)
- Jaetaek Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Chung-Ang University, Seoul, Korea.
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19
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Raza H, Prabu SK, Robin MA, Avadhani NG. Elevated mitochondrial cytochrome P450 2E1 and glutathione S-transferase A4-4 in streptozotocin-induced diabetic rats: tissue-specific variations and roles in oxidative stress. Diabetes 2004; 53:185-94. [PMID: 14693714 DOI: 10.2337/diabetes.53.1.185] [Citation(s) in RCA: 148] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Oxidative stress is an important factor in the etiology and pathogenesis of diabetes. We investigated changes in mitochondrial production of reactive oxygen species (ROS) and mitochondrial antioxidant defense systems in different tissues of streptozotocin (STZ)-induced diabetic rats. Our results show that increased ROS production and oxidative stress differentially affect mitochondrial and cytosolic glutathione (GSH) metabolism. Of the four tissues investigated, the pancreas, kidney, and brain appear to be affected more severely than the liver. We show a five- to eightfold increase of cytochrome P450 2E1 (CYP2E1) and glutathione S-transferase (GST) A4-4 levels in mitochondria from STZ-treated rat tissues compared with those in nondiabetic rat tissues, suggesting possible roles in the disease process. Transient transfection of COS cells with CYP2E1 cDNA caused a similar accumulation of CYP2E1 and GST A4-4 in mitochondria and increased production of mitochondrial ROS. Our results also show an increase in steady-state levels of Hsp70 in the mitochondrial and cytosolic fractions of different tissues of diabetic rats. These results indicate, for the first time, a marked increase in mitochondrial oxidative stress in target tissues of STZ-treated rats and implicate a direct role for mitochondrial CYP2E1 in the generation of intramitochondrial ROS.
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Affiliation(s)
- Haider Raza
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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Park YS, Kim NH, Jo I. Hypoxia and vascular endothelial growth factor acutely up-regulate angiopoietin-1 and Tie2 mRNA in bovine retinal pericytes. Microvasc Res 2003; 65:125-31. [PMID: 12686170 DOI: 10.1016/s0026-2862(02)00035-3] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The angiopoietin/Tie2 system is a predominant regulator of vascular development. This vascular development appears to be controlled and completed by the coordinated actions of two vascular cells, endothelial cells and their surrounding supporting cells, smooth muscle cells, or pericytes. The role of the angiopoietin/Tie2 system has been studied, but these studies are limited mostly to endothelial cells. In this study, using bovine retinal pericytes (BRP), we investigated the effect of two known angiogenic stimuli, hypoxia and vascular endothelial growth factor (VEGF) treatment, on the regulation of the angiopoietin/Tie2 system. Hypoxia (2% O(2) concentration) was acquired by a hypoxia chamber. Both hypoxia and VEGF (10 ng/ml) treatment significantly increased angiopoietin-1 (Ang1) mRNA expression. This marked augmentation occurred acutely (maximal increase at 2 h) and subsequently decreased. In contrast, angiopoietin-2 (Ang2) mRNA expression was unaltered in BRP upon both treatment. Significant up-regulation of Tie2 mRNA expression was found and lasted up to 12 h. However, using bovine aortic endothelial cells (BAEC), we found that only Ang2 expression, but neither Ang1 nor Tie2, responded to these two angiogenic stimuli, which was consistent with many previous reports. In conclusion, our data suggest that both hypoxia and VEGF treatment differentially regulate the angiopoietin/Tie2 system in the two vascular cells and that, particularly in BRP, the regulation of Ang1, but not Ang2, and Tie2 expression may play an important role in vascular development.
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Affiliation(s)
- Yoon Shin Park
- Division of Cardiovascular Research, Department of Biomedical Sciences, National Institute of Health, 5 Nokbun-dong, [122-701], Eunpyung-gu, Seoul, Korea
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