151
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Rong G, Tang X, Guo T, Duan N, Wang Y, Yang L, Zhang J, Liang X. Advanced oxidation protein products induce apoptosis in podocytes through induction of endoplasmic reticulum stress. J Physiol Biochem 2015. [PMID: 26197866 DOI: 10.1007/s13105-015-0424-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Although podocyte apoptosis has been shown to be induced by the accumulation of advanced oxidation protein products (AOPPs), the mechanisms through which AOPPs trigger apoptosis in these cells remain unclear. In this study, we investigated the role of endoplasmic reticulum (ER) stress in AOPP-induced podocyte apoptosis. AOPP treatment induced overexpression of glucose-regulated protein 78 and CCAAT/enhancer-binding protein-homologous protein (CHOP) in podocytes, indicating that AOPPs induced ER stress. Notably, AOPP-induced increase in the rate of podocyte apoptosis was partly reversed by salubrinal, an ER stress inhibitor, whereas the AOPP effect was reproduced by an inducer of ER stress, thapsigargin, suggesting that AOPPs triggered podocyte apoptosis by inducing ER stress. Furthermore, AOPP-induced reactive oxygen species (ROS) generation, ER stress, and podocyte apoptosis were significantly inhibited by an nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor, a ROS scavenger, or receptor of advanced glycation end products (RAGE) small interfering RNA (siRNA). Moreover, silencing of the three ER stress sensors, protein kinase-like ER kinase (PERK), activating transcription factor 6 (ATF6), and inositol requiring 1 (IRE1), respectively, significantly lowered the apoptotic rate of the cells compared with that of the scramble siRNA-transfected cells. Lastly, our data suggested that CHOP- and caspase-12-dependent pathways were involved in ER stress-mediated podocyte apoptosis and that Bcl-2 suppression was involved in CHOP-mediated apoptosis. Collectively, our results indicate for the first time that AOPPs trigger podocyte apoptosis through induction of ER stress, which might be regulated by NADPH oxidase-dependent ROS through RAGE, and that this apoptosis is mediated by three unfolded protein response pathways, the PERK, ATF6, and IRE1 pathways, and the mediators, CHOP and caspase-12.
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Affiliation(s)
- Guang Rong
- Department of Nephrology, Zhujiang Hospital, Southern Medical University, Guangzhou, 510280, People's Republic of China
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152
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Marchant V, Droguett A, Valderrama G, Burgos ME, Carpio D, Kerr B, Ruiz-Ortega M, Egido J, Mezzano S. Tubular overexpression of Gremlin in transgenic mice aggravates renal damage in diabetic nephropathy. Am J Physiol Renal Physiol 2015; 309:F559-68. [PMID: 26155842 DOI: 10.1152/ajprenal.00023.2015] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 06/30/2015] [Indexed: 12/12/2022] Open
Abstract
Diabetic nephropathy (DN) is currently a leading cause of end-stage renal failure worldwide. Gremlin was identified as a gene differentially expressed in mesangial cells exposed to high glucose and in experimental diabetic kidneys. We have described that Gremlin is highly expressed in biopsies from patients with diabetic nephropathy, predominantly in areas of tubulointerstitial fibrosis. In streptozotocin (STZ)-induced experimental diabetes, Gremlin deletion using Grem1 heterozygous knockout mice or by gene silencing, ameliorates renal damage. To study the in vivo role of Gremlin in renal damage, we developed a diabetic model induced by STZ in transgenic (TG) mice expressing human Gremlin in proximal tubular epithelial cells. The albuminuria/creatinuria ratio, determined at week 20 after treatment, was significantly increased in diabetic mice but with no significant differences between transgenic (TG/STZ) and wild-type mice (WT/STZ). To assess the level of renal damage, kidney tissue was analyzed by light microscopy (periodic acid-Schiff and Masson staining), electron microscopy, and quantitative PCR. TG/STZ mice had significantly greater thickening of the glomerular basement membrane, increased mesangial matrix, and podocytopenia vs. WT/STZ. At the tubulointerstitial level, TG/STZ showed increased cell infiltration and mild interstitial fibrosis. In addition, we observed a decreased expression of podocin and overexpression of monocyte chemoattractant protein-1 and fibrotic-related markers, including transforming growth factor-β1, Col1a1, and α-smooth muscle actin. Together, these results show that TG mice overexpressing Gremlin in renal tubules develop greater glomerular and tubulointerstitial injury in response to diabetic-mediated damage and support the involvement of Gremlin in diabetic nephropathy.
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Affiliation(s)
- Vanessa Marchant
- Nephrology Division, School of Medicine, Universidad Austral de Chile, Valdivia, Chile
| | - Alejandra Droguett
- Nephrology Division, School of Medicine, Universidad Austral de Chile, Valdivia, Chile
| | - Graciela Valderrama
- Nephrology Division, School of Medicine, Universidad Austral de Chile, Valdivia, Chile
| | - M Eugenia Burgos
- Nephrology Division, School of Medicine, Universidad Austral de Chile, Valdivia, Chile
| | - Daniel Carpio
- Nephrology Division, School of Medicine, Universidad Austral de Chile, Valdivia, Chile
| | | | - Marta Ruiz-Ortega
- Cellular Biology in Renal Diseases Laboratory, Universidad Autónoma de Madrid (UAM), Instituto de Investigación Sanitaria (IIS)-Fundación Jimenez Diaz, Madrid, Spain; and
| | - Jesús Egido
- Division of Nephrology and Hypertension, IIS-Fundación Jiménez Díaz-UAM/Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, Instituto Reina Sofía de Investigación Nefrológica, Madrid, Spain
| | - Sergio Mezzano
- Nephrology Division, School of Medicine, Universidad Austral de Chile, Valdivia, Chile;
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153
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Pennathur S, Pasichnyk K, Bahrami NM, Zeng L, Febbraio M, Yamaguchi I, Okamura DM. The macrophage phagocytic receptor CD36 promotes fibrogenic pathways on removal of apoptotic cells during chronic kidney injury. THE AMERICAN JOURNAL OF PATHOLOGY 2015; 185:2232-45. [PMID: 26092500 DOI: 10.1016/j.ajpath.2015.04.016] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 04/04/2015] [Accepted: 04/08/2015] [Indexed: 12/19/2022]
Abstract
The removal of apoptotic cells is an innate function of tissue macrophages; however, its role in disease progression is unclear. The present study was designed to investigate the role of macrophage CD36, a recognized receptor of apoptotic cells and oxidized lipids, in two models of kidney injury: unilateral ureteral obstruction (UUO) and ischemia reperfusion. To differentiate the macrophage CD36-specific effects in vivo, we generated CD36 chimeric mice by bone marrow transplantation and evaluated the two models. Fibrosis severity was substantially decreased after UUO with a corresponding decrease in matrix synthesis in macrophage CD36-deficient mice. Despite a reduction in fibrosis severity, a 56% increase in apoptotic cells was found without an increase in apoptotic effectors. In addition, a substantial reduction was observed in tumor necrosis factor-α and transforming growth factor-β1 mRNA levels and intracellular bioactive oxidized lipid levels in CD36-deficient macrophages. To validate the functional role of macrophage CD36, we performed unilateral ischemia reperfusion, followed by contralateral nephrectomy. Similarly, we found that the severity of fibrosis was reduced by 55% with a corresponding improvement in kidney function by 88% in macrophage CD36-deficient mice. Taken together, these data suggest that macrophage CD36 is a critical regulator of oxidative fibrogenic signaling and that CD36-mediated phagocytosis of apoptotic cells may serve as an important pathway in the progression of fibrosis.
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Affiliation(s)
| | - Katie Pasichnyk
- Seattle Children's Hospital Research Institute, University of Washington, Seattle, Washington
| | - Nadia M Bahrami
- Seattle Children's Hospital Research Institute, University of Washington, Seattle, Washington
| | - Lixia Zeng
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Maria Febbraio
- Department of Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Ikuyo Yamaguchi
- Seattle Children's Hospital Research Institute, University of Washington, Seattle, Washington
| | - Daryl M Okamura
- Seattle Children's Hospital Research Institute, University of Washington, Seattle, Washington.
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154
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Abstract
Despite the wealth of pre-clinical support for a role for reactive oxygen and nitrogen species (ROS/RNS) in the aetiology of diabetic complications, enthusiasm for antioxidant therapeutic approaches has been dampened by less favourable outcomes in large clinical trials. This has necessitated a re-evaluation of pre-clinical evidence and a more rational approach to antioxidant therapy. The present review considers current evidence, from both pre-clinical and clinical studies, to address the benefits of antioxidant therapy. The main focus of the present review is on the effects of direct targeting of ROS-producing enzymes, the bolstering of antioxidant defences and mechanisms to improve nitric oxide availability. Current evidence suggests that a more nuanced approach to antioxidant therapy is more likely to yield positive reductions in end-organ injury, with considerations required for the types of ROS/RNS involved, the timing and dosage of antioxidant therapy, and the selective targeting of cell populations. This is likely to influence future strategies to lessen the burden of diabetic complications such as diabetes-associated atherosclerosis, diabetic nephropathy and diabetic retinopathy.
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155
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Heme oxygenase-1 enhances autophagy in podocytes as a protective mechanism against high glucose-induced apoptosis. Exp Cell Res 2015; 337:146-59. [PMID: 25882498 DOI: 10.1016/j.yexcr.2015.04.005] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2014] [Revised: 04/02/2015] [Accepted: 04/04/2015] [Indexed: 11/21/2022]
Abstract
Injury and loss of podocytes play vital roles in diabetic nephropathy progression. Emerging evidence suggests autophagy, which is induced by multiple stressors including hyperglycemia, plays a protective role. Meanwhile, heme oxygenase-1 (HO-1) possesses powerful anti-apoptotic properties. Therefore, we investigated the impact of autophagy on podocyte apoptosis under diabetic conditions and its association with HO-1. Mouse podocytes were cultured in vitro; apoptosis was detected by flow cytometry. Transmission electron microscopy and biochemical autophagic flux assays were used to measure the autophagy markers microtubule-associated protein 1 light chain 3-II (LC3-II) and beclin-1. LC3-II and beclin-1 expression peaked 12-24h after exposing podocytes to high glucose. Inhibition of autophagy with 3-methyladenine or Beclin-1 siRNAs or Atg 5 siRNAs sensitized cells to apoptosis, suggesting autophagy is a survival mechanism. HO-1 inactivation inhibited autophagy, which aggravated podocyte injury in vitro. Hemin-induced autophagy also protected podocytes from hyperglycemia in vitro and was abrogated by HO-1 siRNA. Adenosine monophosphate-activated protein kinase phosphorylation was higher in hemin-treated and lower in HO-1 siRNA-treated podocytes. Suppression of AMPK activity reversed HO-1-mediated Beclin-1 upregulation and autophagy, indicating HO-1-mediated autophagy is AMPK dependent. These findings suggest HO-1 induction and regulation of autophagy are potential therapeutic targets for diabetic nephropathy.
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156
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Shah A, Xia L, Masson EAY, Gui C, Momen A, Shikatani EA, Husain M, Quaggin S, John R, Fantus IG. Thioredoxin-Interacting Protein Deficiency Protects against Diabetic Nephropathy. J Am Soc Nephrol 2015; 26:2963-77. [PMID: 25855771 DOI: 10.1681/asn.2014050528] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 01/22/2015] [Indexed: 12/24/2022] Open
Abstract
Expression of thioredoxin-interacting protein (TxNIP), an endogenous inhibitor of the thiol oxidoreductase thioredoxin, is augmented by high glucose (HG) and promotes oxidative stress. We previously reported that TxNIP-deficient mesangial cells showed protection from HG-induced reactive oxygen species, mitogen-activated protein kinase phosphorylation, and collagen expression. Here, we investigated the potential role of TxNIP in the pathogenesis of diabetic nephropathy (DN) in vivo. Wild-type (WT) control, TxNIP(-/-), and TxNIP(+/-) mice were rendered equally diabetic with low-dose streptozotocin. In contrast to effects in WT mice, diabetes did not increase albuminuria, proteinuria, serum cystatin C, or serum creatinine levels in TxNIP(-/-) mice. Whereas morphometric studies of kidneys revealed a thickened glomerular basement membrane and effaced podocytes in the diabetic WT mice, these changes were absent in the diabetic TxNIP(-/-) mice. Immunohistochemical analysis revealed significant increases in the levels of glomerular TGF-β1, collagen IV, and fibrosis only in WT diabetic mice. Additionally, only WT diabetic mice showed significant increases in oxidative stress (nitrotyrosine, urinary 8-hydroxy-2-deoxy-guanosine) and inflammation (IL-1β mRNA, F4/80 immunohistochemistry). Expression levels of Nox4-encoded mRNA and protein increased only in the diabetic WT animals. A significant loss of podocytes, assessed by Wilms' tumor 1 and nephrin staining and urinary nephrin concentration, was found in diabetic WT but not TxNIP(-/-) mice. Furthermore, in cultured human podocytes exposed to HG, TxNIP knockdown with siRNA abolished the increased mitochondrial O2 (-) generation and apoptosis. These data indicate that TxNIP has a critical role in the progression of DN and may be a promising therapeutic target.
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Affiliation(s)
- Anu Shah
- Department of Medicine and Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto General Research Institute, University Health Network, Department of Physiology, Banting and Best Diabetes Centre, and
| | - Ling Xia
- Department of Medicine and Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto General Research Institute, University Health Network, Banting and Best Diabetes Centre, and
| | - Elodie A Y Masson
- Department of Medicine and Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Banting and Best Diabetes Centre, and
| | - Chloe Gui
- Department of Medicine and Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Banting and Best Diabetes Centre, and
| | - Abdul Momen
- Toronto General Research Institute, University Health Network
| | - Eric A Shikatani
- Toronto General Research Institute, University Health Network, Department of Pathology and Laboratory Medicine, University of Toronto, Toronto, Ontario, Canada, and
| | - Mansoor Husain
- Toronto General Research Institute, University Health Network
| | - Susan Quaggin
- Department of Medicine and Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Banting and Best Diabetes Centre, and Feinberg Cardiovascular Research Institute, Division of Medicine-Nephrology, Northwestern Feinberg School of Medicine, Chicago, Illinois
| | - Rohan John
- Toronto General Research Institute, University Health Network, Department of Pathology and Laboratory Medicine, University of Toronto, Toronto, Ontario, Canada, and
| | - I G Fantus
- Department of Medicine and Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto General Research Institute, University Health Network, Department of Physiology, Banting and Best Diabetes Centre, and
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157
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Abstract
Since the first demonstration of Nox enzyme expression in the kidney in the early 1990s and the subsequent identification of Nox4, or RENOX, a decade later, it has become apparent that the Nox family of reactive oxygen species (ROS) generating enzymes plays an integral role in the normal physiological function of the kidney. As our knowledge of Nox expression patterns and functions in various structures and specialized cell types within the kidney grows, so does the realization that Nox-derived oxidative stress contributes significantly to a wide variety of renal pathologies through their ability to modify lipids and proteins, damage DNA and activate transcriptional programmes. Diverse studies demonstrate key roles for Nox-derived ROS in kidney fibrosis, particularly in settings of chronic renal disease such as diabetic nephropathy. As the most abundant Nox family member in the kidney, much emphasis has been placed on the role of Nox4 in this setting. However, an ever growing body of work continues to uncover key roles for other Nox family members, not only in diabetic kidney disease, but in a diverse array of renal pathological conditions. The objective of the present review is to highlight the latest novel developments in renal Nox biology with an emphasis not only on diabetic nephropathy but many of the other renal disease contexts where oxidative stress is implicated.
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158
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Gorin Y, Wauquier F. Upstream regulators and downstream effectors of NADPH oxidases as novel therapeutic targets for diabetic kidney disease. Mol Cells 2015; 38:285-96. [PMID: 25824546 PMCID: PMC4400302 DOI: 10.14348/molcells.2015.0010] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 01/12/2015] [Indexed: 02/07/2023] Open
Abstract
Oxidative stress has been linked to the pathogenesis of diabetic nephropathy, the complication of diabetes in the kidney. NADPH oxidases of the Nox family, and in particular the homologue Nox4, are a major source of reactive oxygen species in the diabetic kidney and are critical mediators of redox signaling in glomerular and tubulointerstitial cells exposed to the diabetic milieu. Here, we present an overview of the current knowledge related to the understanding of the role of Nox enzymes in the processes that control mesangial cell, podocyte and tubulointerstitial cell injury induced by hyperglycemia and other predominant factors enhanced in the diabetic milieu, including the renin-angiotensin system and transforming growth factor-β. The nature of the upstream modulators of Nox enzymes as well as the downstream targets of the Nox NADPH oxidases implicated in the propagation of the redox processes that alter renal biology in diabetes will be highlighted.
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Affiliation(s)
- Yves Gorin
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas,
USA
| | - Fabien Wauquier
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas,
USA
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159
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Ni WJ, Tang LQ, Wei W. Research progress in signalling pathway in diabetic nephropathy. Diabetes Metab Res Rev 2015; 31:221-33. [PMID: 24898554 DOI: 10.1002/dmrr.2568] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 04/14/2014] [Accepted: 05/31/2014] [Indexed: 11/05/2022]
Abstract
Diabetic nephropathy, a lethal diabetic complication, is a leading cause of end-stage renal disease, which is pathologically characterized by thickened tubular basal and glomerular membranes, accumulated extracellular matrix, and progressive mesangial hypertrophy. Growing evidence indicates that diabetic nephropathy is induced by multiple conditions, such as glucose metabolism disorder, oxidative stress, numerous inflammatory factors and cytokines, and haemodynamic changes that lead to the occurrence and development of diabetic nephropathy based on genetic susceptibility. A variety of abnormalities in the signalling pathway may interact to produce these pathologic processes. Research has aimed to highlight the signalling pathway mechanisms that lead to diabetic nephropathy so that preventative strategies and effective therapies might be developed. In this review, important pathways that appear to be involved in driving these processes are discussed.
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Affiliation(s)
- Wei-Jian Ni
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Hefei 230032, Anhui Province, China; Affiliated Anhui Provincial Hospital, Anhui Medical University, Hefei 230001, Anhui Province, China
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160
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Gorin Y, Cavaglieri RC, Khazim K, Lee DY, Bruno F, Thakur S, Fanti P, Szyndralewiez C, Barnes JL, Block K, Abboud HE. Targeting NADPH oxidase with a novel dual Nox1/Nox4 inhibitor attenuates renal pathology in type 1 diabetes. Am J Physiol Renal Physiol 2015; 308:F1276-87. [PMID: 25656366 DOI: 10.1152/ajprenal.00396.2014] [Citation(s) in RCA: 140] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 02/03/2015] [Indexed: 01/04/2023] Open
Abstract
Reactive oxygen species (ROS) generated by Nox NADPH oxidases may play a critical role in the pathogenesis of diabetic nephropathy (DN). The efficacy of the Nox1/Nox4 inhibitor GKT137831 on the manifestations of DN was studied in OVE26 mice, a model of type 1 diabetes. Starting at 4-5 mo of age, OVE26 mice were treated with GKT137831 at 10 or 40 mg/kg, once-a-day for 4 wk. At both doses, GKT137831 inhibited NADPH oxidase activity, superoxide generation, and hydrogen peroxide production in the renal cortex from diabetic mice without affecting Nox1 or Nox4 protein expression. The increased expression of fibronectin and type IV collagen was reduced in the renal cortex, including glomeruli, of diabetic mice treated with GKT137831. GKT137831 significantly reduced glomerular hypertrophy, mesangial matrix expansion, urinary albumin excretion, and podocyte loss in OVE26 mice. GKT137831 also attenuated macrophage infiltration in glomeruli and tubulointerstitium. Collectively, our data indicate that pharmacological inhibition of Nox1/4 affords broad renoprotection in mice with preexisting diabetes and established kidney disease. This study validates the relevance of targeting Nox4 and identifies GKT137831 as a promising compound for the treatment of DN in type 1 diabetes.
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Affiliation(s)
- Yves Gorin
- Department of Medicine, The University of Texas Health Science Center, San Antonio, Texas;
| | - Rita C Cavaglieri
- Department of Medicine, The University of Texas Health Science Center, San Antonio, Texas
| | - Khaled Khazim
- Department of Medicine, The University of Texas Health Science Center, San Antonio, Texas
| | - Doug-Yoon Lee
- Department of Medicine, The University of Texas Health Science Center, San Antonio, Texas
| | - Francesca Bruno
- Department of Medicine, The University of Texas Health Science Center, San Antonio, Texas
| | - Sachin Thakur
- Department of Medicine, The University of Texas Health Science Center, San Antonio, Texas
| | - Paolo Fanti
- Department of Medicine, The University of Texas Health Science Center, San Antonio, Texas; Audie Leon Murphy Memorial Hospital Division, South Texas Veterans Health Care System, San Antonio, Texas; and
| | | | - Jeffrey L Barnes
- Department of Medicine, The University of Texas Health Science Center, San Antonio, Texas; Audie Leon Murphy Memorial Hospital Division, South Texas Veterans Health Care System, San Antonio, Texas; and
| | - Karen Block
- Department of Medicine, The University of Texas Health Science Center, San Antonio, Texas; Department of Medicine, The University of Texas Health Science Center, San Antonio, Texas
| | - Hanna E Abboud
- Department of Medicine, The University of Texas Health Science Center, San Antonio, Texas; Audie Leon Murphy Memorial Hospital Division, South Texas Veterans Health Care System, San Antonio, Texas; and
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161
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Wang H, Chen X, Su Y, Paueksakon P, Hu W, Zhang MZ, Harris RC, Blackwell TS, Zent R, Pozzi A. p47(phox) contributes to albuminuria and kidney fibrosis in mice. Kidney Int 2015; 87:948-62. [PMID: 25565313 PMCID: PMC4425591 DOI: 10.1038/ki.2014.386] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 09/03/2014] [Accepted: 10/01/2014] [Indexed: 12/19/2022]
Abstract
Reactive oxygen species (ROS) have an important pathogenic role in the development of many diseases, including kidney disease. Major ROS generators in the glomerulus of the kidney are the p47(phox)-containing NAPDH oxidases NOX1 and NOX2. The cytosolic p47(phox) subunit is a key regulator of the assembly and function of NOX1 and NOX2 and its expression and phosphorylation are upregulated in the course of renal injury, and have been shown to exacerbate diabetic nephropathy. However, its role in nondiabetic-mediated glomerular injury is unclear. To address this, we subjected p47(phox)-null mice to either adriamycin-mediated or partial renal ablation-mediated glomerular injury. Deletion of p47(phox) protected the mice from albuminuria and glomerulosclerosis in both injury models. Integrin α1-null mice develop more severe glomerulosclerosis compared with wild-type mice in response to glomerular injury mainly due to increased production of ROS. Interestingly, the protective effects of p47(phox) knockout were more profound in p47(phox)/integrin α1 double knockout mice. In vitro analysis of primary mesangial cells showed that deletion of p47(phox) led to reduced basal levels of superoxide and collagen IV production. Thus, p47(phox)-dependent NADPH oxidases are a major glomerular source of ROS, contribute to kidney injury, and are potential targets for antioxidant therapy in fibrotic disease.
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Affiliation(s)
- Hongtao Wang
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University, Nashville, Tennessee, USA
| | - Xiwu Chen
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University, Nashville, Tennessee, USA
| | - Yan Su
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University, Nashville, Tennessee, USA
| | - Paisit Paueksakon
- Department of Pathology, Immunology, and Microbiology, Vanderbilt University, Nashville, Tennessee, USA
| | - Wen Hu
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University, Nashville, Tennessee, USA
| | - Ming-Zhi Zhang
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University, Nashville, Tennessee, USA
| | - Raymond C Harris
- 1] Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University, Nashville, Tennessee, USA [2] Department of Medicine, Veterans Affairs Hospitals, Nashville, Tennessee, USA
| | - Timothy S Blackwell
- Division of Allergy, Pulmonary, and Critical Care Medicine, Department of Medicine, Vanderbilt University, Nashville, Tennessee, USA
| | - Roy Zent
- 1] Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University, Nashville, Tennessee, USA [2] Department of Medicine, Veterans Affairs Hospitals, Nashville, Tennessee, USA
| | - Ambra Pozzi
- 1] Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University, Nashville, Tennessee, USA [2] Department of Medicine, Veterans Affairs Hospitals, Nashville, Tennessee, USA
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162
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Abstract
PURPOSE OF REVIEW Cytochrome (CYP) P450 metabolites of arachidonic acid, 20-hydroxyeicosatetraenoic acid (20-HETE) and epoxyeicosatrienoic acids (EETs) contribute to the regulation of renal tubular and vascular function. This review highlights the results of the recent genetic studies in humans and rodent models, indicating that these eicosanoids participate in the control of blood pressure (BP), chronic kidney disease (CKD), renal ischemia-reperfusion injury (IRI) and polycystic kidney disease (PKD). RECENT FINDINGS Endogenous 20-HETE has been reported to play an essential role in the myogenic and tubuloglomerular feedback responses in the afferent arteriole, and a deficiency of 20-HETE contributes to the development of hypertension and renal injury in Dahl S rats. Mutations in CYP4A11 and CYP4F2 have been linked to elevated BP in humans. EETs have been shown to regulate epithelial sodium channel in the collecting duct, lower BP and have renoprotective properties. 20-HETE also opposes the development of CKD and IRI, and may play a role in PKD. SUMMARY These studies indicate that CYP P450 metabolites of arachidonic acid play an important role in the control of BP, CKD, AKI and PKD. Drugs targeting these pathways could be useful in the treatment of IRI and CKD.
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Affiliation(s)
- Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi, USA
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163
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Denhez B, Lizotte F, Guimond MO, Jones N, Takano T, Geraldes P. Increased SHP-1 protein expression by high glucose levels reduces nephrin phosphorylation in podocytes. J Biol Chem 2014; 290:350-8. [PMID: 25404734 DOI: 10.1074/jbc.m114.612721] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Nephrin, a critical podocyte membrane component that is reduced in diabetic nephropathy, has been shown to activate phosphotyrosine signaling pathways in human podocytes. Nephrin signaling is important to reduce cell death induced by apoptotic stimuli. We have shown previously that high glucose level exposure and diabetes increased the expression of SHP-1, causing podocyte apoptosis. SHP-1 possesses two Src homology 2 domains that serve as docking elements to dephosphorylate tyrosine residues of target proteins. However, it remains unknown whether SHP-1 interacts with nephrin and whether its elevated expression affects the nephrin phosphorylation state in diabetes. Here we show that human podocytes exposed to high glucose levels exhibited elevated expression of SHP-1, which was associated with nephrin. Coexpression of nephrin-CD16 and SHP-1 reduced nephrin tyrosine phosphorylation in transfected human embryonic kidney 293 cells. A single tyrosine-to-phenylalanine mutation revealed that rat nephrin Tyr(1127) and Tyr(1152) are required to allow SHP-1 interaction with nephrin. Overexpression of dominant negative SHP-1 in human podocytes prevented high glucose-induced reduction of nephrin phosphorylation. In vivo, immunoblot analysis demonstrated that nephrin expression and phosphorylation were decreased in glomeruli of type 1 diabetic Akita mice (Ins2(+/C96Y)) compared with control littermate mice (Ins2(+/+)), and this was associated with elevated SHP-1 and cleaved caspase-3 expression. Furthermore, immunofluorescence analysis indicated increased colocalization of SHP-1 with nephrin in diabetic mice compared with control littermates. In conclusion, our results demonstrate that high glucose exposure increases SHP-1 interaction with nephrin, causing decreased nephrin phosphorylation, which may, in turn, contribute to diabetic nephropathy.
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Affiliation(s)
- Benoit Denhez
- From the Research Center of the Centre Hospitalier Universitaire de Sherbrooke and Division of Endocrinology, Departments of Medicine, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
| | - Farah Lizotte
- From the Research Center of the Centre Hospitalier Universitaire de Sherbrooke and Division of Endocrinology, Departments of Medicine, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
| | - Marie-Odile Guimond
- From the Research Center of the Centre Hospitalier Universitaire de Sherbrooke and Division of Endocrinology, Departments of Medicine, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
| | - Nina Jones
- the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada, and
| | - Tomoko Takano
- the McGill University Health Center, Montreal, Québec H3H 2R9, Canada
| | - Pedro Geraldes
- From the Research Center of the Centre Hospitalier Universitaire de Sherbrooke and Division of Endocrinology, Departments of Medicine, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada,
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Park EC, Kim SI, Hong Y, Hwang JW, Cho GS, Cha HN, Han JK, Yun CH, Park SY, Jang IS, Lee ZW, Choi JS, Kim S, Kim GH. Inhibition of CYP4A reduces hepatic endoplasmic reticulum stress and features of diabetes in mice. Gastroenterology 2014; 147:860-9. [PMID: 24983671 DOI: 10.1053/j.gastro.2014.06.039] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 06/20/2014] [Accepted: 06/24/2014] [Indexed: 01/12/2023]
Abstract
BACKGROUND & AIMS Endoplasmic reticulum (ER) stress is implicated in the development of type 2 diabetes mellitus. ER stress activates the unfolded protein response pathway, which contributes to apoptosis and insulin resistance. We investigated the roles of cytochrome P450 4A (CYP4A) in the regulation of hepatic ER stress, insulin resistance, and the development of diabetes in mice. METHODS We used mass spectrometry to compare levels of CYP450 proteins in livers from C57BL/6J and C57BL/KsJ-db/db (db/db) mice; findings were confirmed by immunoblot and real-time PCR analyses. To create a model of diet-induced diabetes, C57BL/6J mice were placed on high-fat diets. Mice were given intraperitoneal injections of an inhibitor (HET0016) or an inducer (clofibrate) of CYP4A, or tail injections of small hairpin RNAs against CYP4A messenger RNA; liver tissues were collected and analyzed for ER stress, insulin resistance, and apoptosis. The effect of HET0016 and CYP4A knockdown also were analyzed in HepG2 cells. RESULTS Levels of the CYP4A isoforms were highly up-regulated in livers of db/db mice compared with C57BL/6J mice. Inhibition of CYP4A in db/db and mice on high-fat diets reduced features of diabetes such as insulin hypersecretion, hepatic steatosis, and increased glucose tolerance. CYP4A inhibition reduced levels of ER stress, insulin resistance, and apoptosis in the livers of diabetic mice; it also restored hepatic functions. Inversely, induction of CYP4A accelerated ER stress, insulin resistance, and apoptosis in livers of db/db mice. CONCLUSIONS CYP4A proteins are up-regulated in livers of mice with genetically induced and diet-induced diabetes. Inhibition of CYP4A in mice reduces hepatic ER stress, apoptosis, insulin resistance, and steatosis. Strategies to reduce levels or activity of CYP4A proteins in liver might be developed for treatment of patients with type 2 diabetes.
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Affiliation(s)
| | - Seung Il Kim
- Division of Life Science, Korea Basic Science Institute, Daejeon, Republic of Korea
| | - Yeonhee Hong
- Division of Life Science, Korea Basic Science Institute, Daejeon, Republic of Korea
| | - Jeong Won Hwang
- Division of Life Science, Korea Basic Science Institute, Daejeon, Republic of Korea
| | - Gun-Sik Cho
- Division of Molecular and Life Sciences, Pohang University of Science and Technology, Pohang, Kyungbuk, Republic of Korea
| | - Hye-Na Cha
- Department of Physiology, College of Medicine, Yeungnam University, Daegu, Republic of Korea
| | - Jin-Kwan Han
- Division of Molecular and Life Sciences, Pohang University of Science and Technology, Pohang, Kyungbuk, Republic of Korea
| | - Chul-Ho Yun
- School of Biological Sciences and Technology, Chonnam National University, Gwangju, Republic of Korea
| | - So-Young Park
- Department of Physiology, College of Medicine, Yeungnam University, Daegu, Republic of Korea
| | - Ik-Soon Jang
- Division of Life Science, Korea Basic Science Institute, Daejeon, Republic of Korea
| | - Zee-Won Lee
- Division of Life Science, Korea Basic Science Institute, Daejeon, Republic of Korea
| | - Jong-Soon Choi
- Division of Life Science, Korea Basic Science Institute, Daejeon, Republic of Korea; Graduate School of Analytical Science and Technology, Chungnam National University, Daejeon, Republic of Korea
| | | | - Gun-Hwa Kim
- Division of Life Science, Korea Basic Science Institute, Daejeon, Republic of Korea; Department of Functional Genomics, University of Science and Technology, Daejeon, Republic of Korea.
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165
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Ali IHA, Brazil DP. Under the right conditions: protecting podocytes from diabetes-induced damage. Stem Cell Res Ther 2014; 4:119. [PMID: 24083666 PMCID: PMC3854696 DOI: 10.1186/scrt330] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Hyperglycemia-induced damage to the glomerular podocyte is thought to be a critical early event in diabetic nephropathy. Interventions that prevent podocyte damage or loss have been shown to have potential for the treatment of diabetic nephropathy. New data show that conditioned medium from adipocyte-derived mesenchymal stem cells has the potential to protect podocytes from high-glucose-induced damage. Furthermore, epidermal growth factor may be the critical ingredient mediating this effect. These data suggest that components of the conditioned medium of mesenchymal stem cells, in addition to the cells themselves, may have potential for the treatment of diseases such as diabetic nephropathy.
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166
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Li D, Wang N, Zhang L, Hanyu Z, Xueyuan B, Fu B, Shaoyuan C, Zhang W, Xuefeng S, Li R, Chen X. Mesenchymal stem cells protect podocytes from apoptosis induced by high glucose via secretion of epithelial growth factor. Stem Cell Res Ther 2014; 4:103. [PMID: 24004644 PMCID: PMC3856604 DOI: 10.1186/scrt314] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 08/02/2013] [Accepted: 08/23/2013] [Indexed: 12/18/2022] Open
Abstract
Introduction The apoptosis and subsequent injury of podocytes plays a pathogenic role in diabetic nephropathy (DN). Mesenchymal stem cells (MSCs) are promising therapeutic cells for preventing apoptosis and reducing cellular injury. Our previous study found that MSCs could protect kidneys from diabetes-induced injury without obvious engraftment. So we evaluated the effects of human adipose-derived MSCs (hAd-MSCs) on podocytic apoptosis and injury induced by high glucose (HG) and the underlying mechanisms. Methods We used flow cytometry, Western blot and confocal fluorescence microscopy to study podocytic apoptosis and injury induced by HG at 24 hours, 48 hours, and 72 hours in the presence or absence of MSC-conditioned medium (CM). An antibody-based cytokine array was used to identify the mediating factor, which was verified by adding the neutralizing antibody (NtAb) to block its function or adding the recombinant cytokine to the medium to induce its function. Results hAd-MSC-CM reduced podocytic apoptosis in a dose-dependent manner, decreased the expression of podocytic cleaved caspase-3, and prevented the reduced expression and maintained the normal arrangement of podocytic synaptopodin and nephrin. However, human embryonic lung cell (Wi38)-CM failed to ameliorate podocytic apoptosis or injury. Twelve cytokines with concentration ratios (MSC-CM/Wi38-CM) >10-fold were identified. Epithelial growth factor (EGF) was singled out for its known ability to prevent apoptosis. Recombinant human EGF (rhEGF) prevented podocytic apoptosis and injury similarly to hAd-MSC-CM but, upon blockade of EGF, the beneficial effect of hAd-MSC-CM decreased dramatically. Conclusions hAd-MSCs prevent podocytic apoptosis and injury induced by HG, mainly through secreting soluble EG.
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167
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Chen J, Chen JK, Harris RC. EGF receptor deletion in podocytes attenuates diabetic nephropathy. J Am Soc Nephrol 2014; 26:1115-25. [PMID: 25185988 DOI: 10.1681/asn.2014020192] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 07/30/2014] [Indexed: 11/03/2022] Open
Abstract
The generation of reactive oxygen species (ROS), particularly superoxide, by damaged or dysfunctional mitochondria has been postulated to be an initiating event in the development of diabetes complications. The glomerulus is a primary site of diabetic injury, and podocyte injury is a classic hallmark of diabetic glomerular lesions. In streptozotocin-induced type 1 diabetes, podocyte-specific EGF receptor (EGFR) knockout mice (EGFR(podKO)) and their wild-type (WT) littermates had similar levels of hyperglycemia and polyuria, but EGFR(podKO) mice had significantly less albuminuria and less podocyte loss compared with WT diabetic mice. Furthermore, EGFR(podKO) diabetic mice had less TGF-β1 expression, Smad2/3 phosphorylation, and glomerular fibronectin deposition. Immunoblotting of isolated glomerular lysates revealed that the upregulation of cleaved caspase 3 and downregulation of Bcl2 in WT diabetic mice were attenuated in EGFR(podKO) diabetic mice. Administration of the SOD mimetic mito-tempol or the NADPH oxidase inhibitor apocynin attenuated the upregulation of p-c-Src, p-EGFR, p-ERK1/2, p-Smad2/3, and TGF-β1 expression and prevented the alteration of cleaved caspase 3 and Bcl2 expression in glomeruli of WT diabetic mice. High-glucose treatment of cultured mouse podocytes induced similar alterations in the production of ROS; phosphorylation of c-Src, EGFR, and Smad2/3; and expression of TGF-β1, cleaved caspase 3, and Bcl2. These alterations were inhibited by treatment with mito-tempol or apocynin or by inhibiting EGFR expression or activity. Thus, results of our studies utilizing mice with podocyte-specific EGFR deletion demonstrate that EGFR activation has a major role in activating pathways that mediate podocyte injury and loss in diabetic nephropathy.
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Affiliation(s)
- Jianchun Chen
- Department of Veterans Affairs, Nashville, Tennessee; Departments of Medicine and
| | - Jian-Kang Chen
- Departments of Cellular Biology and Anatomy and Medicine, Medical College of Georgia, Georgia Regents University, Augusta, Georgia
| | - Raymond C Harris
- Department of Veterans Affairs, Nashville, Tennessee; Departments of Medicine and Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee; and
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168
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Gangadhariah MH, Luther JM, Garcia V, Paueksakon P, Zhang MZ, Hayward SW, Love HD, Falck JR, Manthati VL, Imig JD, Schwartzman ML, Zent R, Capdevila JH, Pozzi A. Hypertension is a major contributor to 20-hydroxyeicosatetraenoic acid-mediated kidney injury in diabetic nephropathy. J Am Soc Nephrol 2014; 26:597-610. [PMID: 25071086 DOI: 10.1681/asn.2013090980] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
In the kidney, 20-hydroxyeicosatetraenoic acid (20-HETE) is a primary cytochrome P450 4 (Cyp4)-derived eicosanoid that enhances vasoconstriction of renal vessels and induces hypertension, renal tubular cell hypertrophy, and podocyte apoptosis. Hypertension and podocyte injury contribute to diabetic nephropathy and are strong predictors of disease progression. In this study, we defined the mechanisms whereby 20-HETE affects the progression of diabetic nephropathy. We used Cyp4a14KO male mice that exhibit androgen-sensitive hypertension due to increased Cyp4a12-mediated 20-HETE production. We show that, upon induction of diabetes type 1 via streptozotocin injection, Cyp4a14KO male mice developed worse renal disease than streptozotocin-treated wild-type mice, characterized by increased albuminuria, mesangial expansion, glomerular matrix deposition, and thickness of the glomerular basement membranes. Castration blunted androgen-mediated Cyp4a12 synthesis and 20-HETE production, normalized BP, and ameliorated renal damage in diabetic Cyp4a14KO mice. Notably, treatment with a 20-HETE antagonist or agents that normalized BP without affecting Cyp4a12 expression and 20-HETE biosynthesis also ameliorated diabetes-mediated renal damage and albuminuria in Cyp4a14KO male mice. Taken together, these results suggest that hypertension is the major contributor to 20-HETE-driven diabetes-mediated kidney injury.
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Affiliation(s)
| | - James M Luther
- Clinical Pharmacology, Department of Medicine, Vanderbilt University, Nashville, Tennessee
| | - Victor Garcia
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | | | | | - Simon W Hayward
- Urologic Surgery; Vanderbilt University, Nashville, Tennessee
| | - Harold D Love
- Urologic Surgery; Vanderbilt University, Nashville, Tennessee
| | - John R Falck
- Division of Chemistry, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Vijaya L Manthati
- Division of Chemistry, University of Texas Southwestern Medical Center, Dallas, Texas
| | - John D Imig
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin; and
| | | | - Roy Zent
- Divisions of Nephrology and Department of Medicine, Veterans Affairs Hospitals, Nashville, Tennessee
| | | | - Ambra Pozzi
- Divisions of Nephrology and Department of Medicine, Veterans Affairs Hospitals, Nashville, Tennessee
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169
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Homocysteine in renovascular complications: hydrogen sulfide is a modulator and plausible anaerobic ATP generator. Nitric Oxide 2014; 41:27-37. [PMID: 24963795 DOI: 10.1016/j.niox.2014.06.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 06/16/2014] [Accepted: 06/17/2014] [Indexed: 11/23/2022]
Abstract
Homocysteine (Hcy) is a non-protein amino acid derived from dietary methionine. High levels of Hcy, known as hyperhomocysteinemia (HHcy) is known to cause vascular complications. In the mammalian tissue, Hcy is metabolized by transsulfuration enzymes to produce hydrogen sulfide (H2S). H2S, a pungent smelling gas was previously known for its toxic effects in the central nervous system, recent studies however has revealed protective effects in a variety of diseases including hypertension, diabetes, inflammation, atherosclerosis, and renal disease progression and failure. Interestingly, under stress conditions including hypoxia, H2S can reduce metabolic demand and also act as a substrate for ATP production. This review highlights some of the recent advances in H2S research as a potential therapeutic agent targeting renovascular diseases associated with HHcy.
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170
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Komers R, Xu B, Fu Y, McClelland A, Kantharidis P, Mittal A, Cohen HT, Cohen DM. Transcriptome-based analysis of kidney gene expression changes associated with diabetes in OVE26 mice, in the presence and absence of losartan treatment. PLoS One 2014; 9:e96987. [PMID: 24827579 PMCID: PMC4020814 DOI: 10.1371/journal.pone.0096987] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 04/14/2014] [Indexed: 12/24/2022] Open
Abstract
Diabetes is among the most common causes of end-stage renal disease, although its pathophysiology is incompletely understood. We performed next-generation sequencing-based transcriptome analysis of renal gene expression changes in the OVE26 murine model of diabetes (age 15 weeks), relative to non-diabetic control, in the presence and absence of short-term (seven-day) treatment with the angiotensin receptor blocker, losartan (n = 3-6 biological replicates per condition). We detected 1438 statistically significant changes in gene expression across conditions. Of the 638 genes dysregulated in diabetes relative to the non-diabetic state, >70% were downregulation events. Unbiased functional annotation of genes up- and down-regulated by diabetes strongly associated (p<1 × 10(-8)) with terms for oxidative stress and for endoplasmic reticulum stress/protein folding. Most of the individual gene products up- or down-regulated with diabetes were unaffected by losartan treatment; however, of the gene products dysregulated in diabetes and influenced by losartan treatment, the vast majority of changes were in the direction of amelioration rather than exacerbation of the diabetic dysregulation. This group of losartan-protected genes associated strongly with annotation terms for endoplasmic reticulum stress, heat shock proteins, and chaperone function, but not oxidative stress; therefore, the losartan-unaffected genes suggest avenues for additional therapeutic opportunity in diabetes. Interestingly, the gene product most highly upregulated by diabetes (>52-fold), encoded by the cationic amino acid transporter Slc7a12, and the gene product most highly downregulated by diabetes (>99%)--encoded by the "pseudogene" Gm6300--are adjacent in the murine genome, are members of the SLC7 gene family, and are likely paralogous. Therefore, diabetes activates a near-total genetic switch between these two paralogs. Other individual-level changes in gene expression are potentially relevant to diabetic pathophysiology, and novel pathways are suggested. Genes unaffected by diabetes alone but exhibiting increased renal expression with losartan produced a signature consistent with malignant potential.
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Affiliation(s)
- Radko Komers
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health & Science University, Portland, Oregon
- Portland V. A. Medical Center, Portland, Oregon, United States of America
| | - Bei Xu
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health & Science University, Portland, Oregon
- Portland V. A. Medical Center, Portland, Oregon, United States of America
| | - Yi Fu
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health & Science University, Portland, Oregon
- Portland V. A. Medical Center, Portland, Oregon, United States of America
| | - Aaron McClelland
- JDRF Danielle Alberti Memorial Centre for Diabetes Complications, Diabetes Division, Baker IDI Heart and Diabetes Institute, Melbourne, Australia
| | - Phillip Kantharidis
- JDRF Danielle Alberti Memorial Centre for Diabetes Complications, Diabetes Division, Baker IDI Heart and Diabetes Institute, Melbourne, Australia
| | - Amit Mittal
- Nephrology Section, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Herbert T. Cohen
- Nephrology Section, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - David M. Cohen
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health & Science University, Portland, Oregon
- Portland V. A. Medical Center, Portland, Oregon, United States of America
- * E-mail:
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171
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Reshi ML, Su YC, Hong JR. RNA Viruses: ROS-Mediated Cell Death. Int J Cell Biol 2014; 2014:467452. [PMID: 24899897 PMCID: PMC4034720 DOI: 10.1155/2014/467452] [Citation(s) in RCA: 172] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Revised: 03/18/2014] [Accepted: 03/20/2014] [Indexed: 12/14/2022] Open
Abstract
Reactive oxygen species (ROS) are well known for being both beneficial and deleterious. The main thrust of this review is to investigate the role of ROS in ribonucleic acid (RNA) virus pathogenesis. Much evidences has accumulated over the past decade, suggesting that patients infected with RNA viruses are under chronic oxidative stress. Changes to the body's antioxidant defense system, in relation to SOD, ascorbic acid, selenium, carotenoids, and glutathione, have been reported in various tissues of RNA-virus infected patients. This review focuses on RNA viruses and retroviruses, giving particular attention to the human influenza virus, Hepatitis c virus (HCV), human immunodeficiency virus (HIV), and the aquatic Betanodavirus. Oxidative stress via RNA virus infections can contribute to several aspects of viral disease pathogenesis including apoptosis, loss of immune function, viral replication, inflammatory response, and loss of body weight. We focus on how ROS production is correlated with host cell death. Moreover, ROS may play an important role as a signal molecule in the regulation of viral replication and organelle function, potentially providing new insights in the prevention and treatment of RNA viruses and retrovirus infections.
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Affiliation(s)
- Mohammad Latif Reshi
- Laboratory of Molecular Virology and Biotechnology, Institute of Biotechnology, National Cheng Kung University, Tainan 701, Taiwan
- Department of Life Sciences, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan 701, Taiwan
| | - Yi-Che Su
- Laboratory of Molecular Virology and Biotechnology, Institute of Biotechnology, National Cheng Kung University, Tainan 701, Taiwan
| | - Jiann-Ruey Hong
- Laboratory of Molecular Virology and Biotechnology, Institute of Biotechnology, National Cheng Kung University, Tainan 701, Taiwan
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172
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Papadimitriou A, Peixoto EBMI, Silva KC, Lopes de Faria JM, Lopes de Faria JB. Increase in AMPK brought about by cocoa is renoprotective in experimental diabetes mellitus by reducing NOX4/TGFβ-1 signaling. J Nutr Biochem 2014; 25:773-84. [PMID: 24768660 DOI: 10.1016/j.jnutbio.2014.03.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 02/18/2014] [Accepted: 03/10/2014] [Indexed: 12/12/2022]
Abstract
The aims of the present study were to investigate, in diabetes mellitus (DM), the mechanism of NOX4 up-regulation, its link with 5' adenosine monophosphate-activated protein kinase (AMPK) inactivation and transforming growth factor (TGF) ß-1 signaling in determining the accumulation of kidney extracellular matrix (ECM), and the possible action of cocoa enriched with polyphenols (CH) in these events. After 16 weeks of DM, spontaneously hypertensive rats showed increased kidney TGFβ-1 levels and expression of phosphorylated smad2, collagen IV and fibronectin in parallel with elevated NOX4 expression and reduced phosphorylated AMPK. CH treatment in diabetic rats prevented all of these abnormalities. In immortalized human mesangial cells exposed to high glucose (HG), or TGFβ-1, CH, nicotinamide adenine dinucleotide phosphate blocker, or silencing NOX4 ameliorated enhanced phosphorylated smad2 and collagen IV. Reduction in phosphorylated AMPK induced by HG or TGFβ-1 was ameliorated by CH or activation of AMPK, which reduced phosphorylation of smad2 and collagen IV via reduction in NOX4 expression. The effects of CH were abolished by AMPK blockade. These results suggest that inactivation in AMPK leads to NOX4 up-regulation, activation of TGFβ-1 signaling and increased ECM accumulation. Additionally, increased TGF-ß1 per se leads to the amplification of ECM production by reducing AMPK and promoting the activation of NOX4. It is suggested that the activation of AMPK by CH followed by reduction in NOX4/TGFβ-1 signaling may have a therapeutic potential in diabetic nephropathy.
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Affiliation(s)
- Alexandros Papadimitriou
- Renal Pathophysiology Laboratory, Investigation on Diabetes Complications, Faculty of Medical Sciences, State University of Campinas (Unicamp), Campinas, São Paulo, Brazil.
| | - Elisa B M I Peixoto
- Renal Pathophysiology Laboratory, Investigation on Diabetes Complications, Faculty of Medical Sciences, State University of Campinas (Unicamp), Campinas, São Paulo, Brazil.
| | - Kamila C Silva
- Renal Pathophysiology Laboratory, Investigation on Diabetes Complications, Faculty of Medical Sciences, State University of Campinas (Unicamp), Campinas, São Paulo, Brazil.
| | - Jacqueline M Lopes de Faria
- Renal Pathophysiology Laboratory, Investigation on Diabetes Complications, Faculty of Medical Sciences, State University of Campinas (Unicamp), Campinas, São Paulo, Brazil.
| | - José B Lopes de Faria
- Renal Pathophysiology Laboratory, Investigation on Diabetes Complications, Faculty of Medical Sciences, State University of Campinas (Unicamp), Campinas, São Paulo, Brazil.
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173
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Matsumoto M, Katsuyama M, Iwata K, Ibi M, Zhang J, Zhu K, Nauseef WM, Yabe-Nishimura C. Characterization of N-glycosylation sites on the extracellular domain of NOX1/NADPH oxidase. Free Radic Biol Med 2014; 68:196-204. [PMID: 24361341 DOI: 10.1016/j.freeradbiomed.2013.12.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 11/27/2013] [Accepted: 12/12/2013] [Indexed: 01/12/2023]
Abstract
Extensive evidence demonstrates the pathophysiological importance of NOX1, the catalytic subunit of superoxide-generating enzyme NADPH oxidase, as a source of reactive oxygen species in nonphagocytic cells. However, the biochemical properties of NOX1 have not been extensively characterized due to a lack of specific immunological tools. We used a newly raised NOX1 polyclonal antibody to investigate posttranslational modifications of NOX1 overexpressed in cultured cells and in the colon, where endogenous NOX1 is highly expressed. Immunoblots of lysates from cells expressing NOX1 revealed a doublet of 56 and 60kDa accompanied by a broad band of 60-90kDa. Based on differential sensitivity to glycosidases, the doublet was identified as two high-mannose-type glycoforms of NOX1, whereas the broad band represented NOX1 with complex-type N-linked oligosaccharides. Deglycosylated NOX1 migrated at ~53kDa and N-glycosylation was demonstrated in NOX1 derived from both rat and human. Site-directed mutagenesis identified N-glycosylation sites at Asn(161) and Asn(241) on the extracellular loop of mouse NOX1. Elimination of N-glycosylation on NOX1 did not affect its electron transferase activity, protein stability, targeting to the cell surface, or localization in F-actin-positive membrane protrusions. Taken together, these data identify the two specific sites of N-linked glycosylation of murine NOX1 and demonstrate that they are not required for normal enzyme activity, protein stability, and membrane trafficking. As is true for NOX2, the contribution of glycosylation in NOX1 to its biologic function(s) merits further study.
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Affiliation(s)
- Misaki Matsumoto
- Department of Pharmacology, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
| | - Masato Katsuyama
- Radioisotope Center, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Kazumi Iwata
- Department of Pharmacology, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Masakazu Ibi
- Department of Pharmacology, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Jia Zhang
- Department of Pharmacology, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Kai Zhu
- Department of Pharmacology, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - William M Nauseef
- Inflammation Program and Department of Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Coralville, IA 52241, USA; Veterans Administration Medical Center, Iowa City, IA 52240, USA
| | - Chihiro Yabe-Nishimura
- Department of Pharmacology, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
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174
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Gray SP, Jha JC, Di Marco E, Jandeleit-Dahm KA. NAD(P)H oxidase isoforms as therapeutic targets for diabetic complications. Expert Rev Endocrinol Metab 2014; 9:111-122. [PMID: 30743754 DOI: 10.1586/17446651.2014.887984] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The development of macro- and microvascular complications is accelerated in diabetic patients. While some therapeutic regimes have helped in delaying progression of complications, none have yet been able to halt the progression and prevent vascular disease, highlighting the need to identify new therapeutic targets. Increased oxidative stress derived from the NADPH oxidase (Nox) family has recently been identified to play an important role in the pathophysiology of vascular disease. In recent years, specific Nox isoforms have been implicated in contributing to the development of atherosclerosis of major vessels, as well as damage of the small vessels within the kidney and the eye. With the use of novel Nox inhibitors, it has been demonstrated that these complications can be attenuated, indicating that targeting Nox derived oxidative stress holds potential as a new therapeutic strategy.
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Affiliation(s)
| | - Jay C Jha
- a Diabetic Complications Division, Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Elyse Di Marco
- a Diabetic Complications Division, Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Karin Am Jandeleit-Dahm
- a Diabetic Complications Division, Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia
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175
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Shimamoto N. [A pathophysiological role of cytochrome p450 involved in production of reactive oxygen species]. YAKUGAKU ZASSHI 2014; 133:435-50. [PMID: 23546588 DOI: 10.1248/yakushi.12-00263] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Dysregulation of the production of reactive oxygen species (ROS) determines cellular function. Cytochrome P450s (CYPs) regulates ROS production and contributes to the process of cell death. This review summarizes our recent findings, focusing on the involvement of CYPs in pathophysiology induced by ROS. 1. Quinone toxicity in hepatocytes: CYPs require electrons supplied from NADPH-cytochrome P450 reductase (NPR) during the process of metabolism. NPR also provides electrons to quinone compounds, which compete with CYPs over electrons. Inhibition of CYPs shifts NPR's electron flow more to quinones, which accelerates the redox cycle to enhance ROS production and quinone toxicity. 2. Myocardial ischemia-reperfusion injury: Reperfusion of blood flow after coronary artery occlusion induces cell damage, as evident by the extension of myocardial infarct size and caspase-independent cell apoptosis. CYP2C6 appears to be a source for ROS production, since sulfaphenazole, a selective inhibitor of CYP2C6, reduces this damage. ROS produced by CYP2C6 during the reperfusion causes translational activation of Noxa and BimEL, as well as the suppression of caspase activation, resulting in caspase-independent apoptosis. 3. Primary hepatocyte apoptosis: Inhibition of catalase and glutathione peroxidase increases intracellular ROS and elicits caspase-independent hepatocyte apoptosis. SKF-525A, a pan-CYP inhibitor, suppresses these ROS increases and hepatocyte apoptosis. Increased ROS activates ERK and AP-1 by inhibition of tyrosine phosphatase, and inhibits BimEL degradation by proteasome. These results in the accumulation of mitochondrial BimEL, which then induces the release of cytochrome c and endonuclease G (EndoG). Increased ROS also keeps caspases inactivated. As a result, EndoG executes nucleosomal DNA fragmentation.
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Affiliation(s)
- Norio Shimamoto
- Laboratory of Pharmacology, Faculty of Pharmaceutical Sciences at Kagawa, Tokushima Bunri University, Kagawa 769-2193, Japan
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Yang HY, Wu LY, Yeh WJ, Chen JR. Beneficial effects of β-conglycinin on renal function and nephrin expression in early streptozotocin-induced diabetic nephropathy rats. Br J Nutr 2014; 111:78-85. [PMID: 23803175 DOI: 10.1017/s0007114513001876] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The objective of the present study was to investigate the effects of β-conglycinin and soya isoflavones on diabetic nephropathy (DN). DN was induced by an intravenous injection of streptozotocin (25 mg/kg) in spontaneously hypertensive rats. DN rats were divided into a non-diabetic group (C, control group) and three DN groups (D, DN with control diet; B, DN+control diet with one-eighth of casein replaced by β-conglycinin as the protein source; and I, DN+control diet with 0·01 % soya isoflavones). After a 4-week experimental period, we found that fasting blood sugar and plasma and kidney advanced glycation end product levels and 24 h urinary protein excretion of the B group were significantly lower than those of the D group and insulin sensitivity and nephrin expression of the B group were significantly higher than those of the D group. In addition, systolic blood pressure, angiotensin-converting enzyme activity, angiotensin II level and plasma TAG level of the B group were significantly lower than those of the D group, whereas only the levels of plasma TAG and thiobarbituric acid-reactive substances of the I group were lower than those of the D group. In conclusion, β-conglycinin may be beneficial for retarding DN progression and this effect cannot be completely explained by its isoflavone content.
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MESH Headings
- Angiotensin II/blood
- Animals
- Antigens, Plant/pharmacology
- Antigens, Plant/therapeutic use
- Blood Glucose/metabolism
- Blood Pressure/drug effects
- Diabetes Mellitus, Experimental/complications
- Diabetes Mellitus, Experimental/diet therapy
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/physiopathology
- Diabetes Mellitus, Type 2/complications
- Diabetes Mellitus, Type 2/diet therapy
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/physiopathology
- Diabetic Nephropathies/diet therapy
- Diabetic Nephropathies/metabolism
- Diabetic Nephropathies/physiopathology
- Dietary Proteins/pharmacology
- Dietary Proteins/therapeutic use
- Globulins/pharmacology
- Globulins/therapeutic use
- Glycation End Products, Advanced/metabolism
- Insulin Resistance
- Isoflavones/pharmacology
- Kidney/drug effects
- Kidney/metabolism
- Kidney/physiopathology
- Male
- Membrane Proteins/metabolism
- Peptidyl-Dipeptidase A/metabolism
- Phytotherapy
- Plant Preparations/pharmacology
- Plant Preparations/therapeutic use
- Rats
- Rats, Inbred SHR
- Seed Storage Proteins/pharmacology
- Seed Storage Proteins/therapeutic use
- Soybean Proteins/pharmacology
- Soybean Proteins/therapeutic use
- Glycine max/chemistry
- Thiobarbituric Acid Reactive Substances
- Triglycerides/blood
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Affiliation(s)
- Hsin-Yi Yang
- Department of Nutrition, I-Shou University, Kaohsiung 824, Taiwan, ROC
| | - Lin-Yi Wu
- School of Nutrition and Health Sciences, Taipei Medical University, Taipei 110, Taiwan, ROC
| | - Wan-Ju Yeh
- School of Nutrition and Health Sciences, Taipei Medical University, Taipei 110, Taiwan, ROC
| | - Jiun-Rong Chen
- School of Nutrition and Health Sciences, Taipei Medical University, Taipei 110, Taiwan, ROC
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177
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The effect of resveratrol on the expression of AdipoR1 in kidneys of diabetic nephropathy. Mol Biol Rep 2014; 41:2151-9. [PMID: 24413998 DOI: 10.1007/s11033-014-3064-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 01/04/2014] [Indexed: 12/17/2022]
Abstract
Adiponectin is an adipocyte derived protein that plays pivotal roles in anti-oxidation, anti-inflammatory and insulin-sensitizing properties by activating two receptors, AdipoR1 and AdipoR2. Recent studies have shown that the down-regulation of AdipoR1 is a known cause of diabetic nephropathy (DN). Resveratrol (Resv), a natural polyphenol, has been identified as a potent activator of forkhead transcription factor O1 (FoxO1) which can up-regulate the expression of AdipoR1. In the present study, we have investigated whether Resv can up-regulate the expression of AdipoR1 by activating FoxO1 that is in kidney of DN rats and mesangial cells (MCs) cultured in high glucose (HG, 30 mmol/L) medium. In vivo, we show that, in the renal cortex of diabetic rats, the expression of AdipoR1 was significantly reduced and correlated with an increase in the generation of malondialdehyde (MDA), Collagen IV and fibronectin proteins. However, administration with Resv significantly increased the expression of AdipoR1. This correlated with not only a decrease in generation of MDA, Collagen IV and fibronectin proteins levels but also more improved kidney pathological and biochemical indicators changes. In vitro, we show that HG-induced depression of FoxO1 activity was associated with the expression of Adipor1 in MCs. Treatment with Resv (20 μmol/L) caused an elevation in the activity of FoxO1 and a significantly increase in the expression of AdipoR1. Furthermore, inhibition of FoxO1 through short hairpin RNA markedly reduced the expression of Adipor1 in MCs cultured by Resv. In conclusion, Resv can significantly increase the expression of AdipoR1 by activating FoxO1 in diabetic kidney. These data also suggest that Resv may serve as a promising agent for preventing or treating DN.
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178
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Riera M, Márquez E, Clotet S, Gimeno J, Roca-Ho H, Lloreta J, Juanpere N, Batlle D, Pascual J, Soler MJ. Effect of insulin on ACE2 activity and kidney function in the non-obese diabetic mouse. PLoS One 2014; 9:e84683. [PMID: 24400109 PMCID: PMC3882249 DOI: 10.1371/journal.pone.0084683] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Accepted: 11/26/2013] [Indexed: 11/18/2022] Open
Abstract
We studied the non-obese diabetic (NOD) mice model because it develops autoimmune diabetes that resembles human type 1 diabetes. In diabetic mice, urinary albumin excretion (UAE) was ten-fold increased at an "early stage" of diabetes, and twenty-fold increased at a "later stage" (21 and 40 days, respectively after diabetes diagnosis) as compared to non-obese resistant controls. In NOD Diabetic mice, glomerular enlargement, increased glomerular filtration rate (GFR) and increased blood pressure were observed in the early stage. In the late stage, NOD Diabetic mice developed mesangial expansion and reduced podocyte number. Circulating and urine ACE2 activity were markedly increased both, early and late in Diabetic mice. Insulin administration prevented albuminuria, markedly reduced GFR, blood pressure, and glomerular enlargement in the early stage; and prevented mesangial expansion and the reduced podocyte number in the late stage of diabetes. The increase in serum and urine ACE2 activity was normalized by insulin administration at the early and late stages of diabetes in Diabetic mice. We conclude that the Diabetic mice develops features of early kidney disease, including albuminuria and a marked increase in GFR. ACE2 activity is increased starting at an early stage in both serum and urine. Moreover, these alterations can be completely prevented by the chronic administration of insulin.
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Affiliation(s)
- Marta Riera
- Department of Nephrology, Hospital del Mar-IMIM, Barcelona, Spain
| | - Eva Márquez
- Department of Nephrology, Hospital del Mar-IMIM, Barcelona, Spain
| | - Sergi Clotet
- Department of Nephrology, Hospital del Mar-IMIM, Barcelona, Spain
| | - Javier Gimeno
- Department of Pathology, Hospital del Mar-IMIM, Barcelona, Spain
| | - Heleia Roca-Ho
- Department of Pathology, Hospital del Mar-IMIM, Barcelona, Spain
| | - Josep Lloreta
- Department of Pathology, Hospital del Mar-IMIM, Barcelona, Spain
| | - Nuria Juanpere
- Department of Pathology, Hospital del Mar-IMIM, Barcelona, Spain
| | - Daniel Batlle
- Division of Nephrology and Hypertension, Department of Medicine, The Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Julio Pascual
- Department of Nephrology, Hospital del Mar-IMIM, Barcelona, Spain
| | - María José Soler
- Department of Nephrology, Hospital del Mar-IMIM, Barcelona, Spain
- * E-mail:
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179
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Anil Kumar P, Welsh GI, Saleem MA, Menon RK. Molecular and cellular events mediating glomerular podocyte dysfunction and depletion in diabetes mellitus. Front Endocrinol (Lausanne) 2014; 5:151. [PMID: 25309512 PMCID: PMC4174857 DOI: 10.3389/fendo.2014.00151] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 09/10/2014] [Indexed: 12/11/2022] Open
Abstract
The essential function of the kidney is to ensure formation of a relatively protein-free ultra-filtrate, urine. The rate of filtration and composition of the primary renal filtrate is determined by the transport of fluid and solutes across the glomerular filtration barrier consisting of endothelial cells, the glomerular basement membrane, and podocyte foot processes. In diabetes mellitus (DM), components of the kidney that enable renal filtration get structurally altered and functionally compromised resulting in proteinuria that often progresses to end-stage renal disease. Histological alterations in DM include early hypertrophy of glomerular and tubular components, subsequent thickening of basement membrane in glomeruli and tubules, progressive accumulation of extracellular matrix proteins in the glomerular mesangium and loss of podocytes, together constituting a clinical condition referred to as diabetic nephropathy (DN). The glomerulus has become the focus of research investigating the mechanism of proteinuria. In particular, the progressive dysfunction and/or loss of podocytes that is contemporaneous with proteinuria in DN have attracted intense scientific attention. The absolute number of podocytes predicts glomerular function and podocyte injury is a hallmark of various glomerular diseases. This review discusses the importance of podocytes in normal renal filtration and details the molecular and cellular events that lead to podocyte dysfunction and decreased podocyte count in DN.
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Affiliation(s)
- P. Anil Kumar
- Department of Biochemistry, University of Hyderabad, Hyderabad, India
| | - Gavin I. Welsh
- Academic Renal Unit, School of Clinical Sciences, University of Bristol, Bristol, UK
| | - Moin A. Saleem
- Academic Renal Unit, School of Clinical Sciences, University of Bristol, Bristol, UK
| | - Ram K. Menon
- Pediatric Endocrinology and Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
- *Correspondence: Ram K. Menon, University of Michigan Medical School, D1205 MPB/SPC 5718, 1500 E. Medical Center Drive, Ann Arbor, MI 48109-5718, USA e-mail:
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180
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Yacoub R, Lee K, He JC. The Role of SIRT1 in Diabetic Kidney Disease. Front Endocrinol (Lausanne) 2014; 5:166. [PMID: 25346724 PMCID: PMC4191277 DOI: 10.3389/fendo.2014.00166] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 09/25/2014] [Indexed: 01/13/2023] Open
Abstract
Sirtuins (SIRTs) are members of the silent information regulator 2 family. In mammals, of the seven known SIRTs, SIRT1 function is most studied and has been shown to regulate wide range of cellular functions that affect metabolic homeostasis and aging. SIRT1 exerts anti-apoptotic, anti-oxidative, and anti-inflammatory effects against cellular injury, and protects the cells through the regulation of mitochondrial biogenesis, autophagy, and metabolism in response to the cellular energy and redox status. SIRT1 also promotes vasodilation and protects vascular tissues. In humans and animal models with diabetic kidney disease (DKD), its expression tends to be decreased in renal cells, and increased expression of SIRT1 was found to play a renal protective role in animal models with DKD. In this review, we discuss the role and potential mechanisms by which SIRT1 protects against DKD.
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Affiliation(s)
- Rabi Yacoub
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Kyung Lee
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - John Cijiang He
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- *Correspondence: John Cijiang He, Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, One Gustave L Levy Place, Box 1243, New York, NY 10029, USA e-mail:
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181
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Williams CR, Gooch JL. Calcineurin Aβ regulates NADPH oxidase (Nox) expression and activity via nuclear factor of activated T cells (NFAT) in response to high glucose. J Biol Chem 2013; 289:4896-905. [PMID: 24371139 DOI: 10.1074/jbc.m113.514869] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Hypertrophy is an adaptive response that enables organs to appropriately meet increased functional demands. Previously, we reported that calcineurin (Cn) is required for glomerular and whole kidney hypertrophy in diabetic rodents (Gooch, J. L., Barnes, J. L., Garcia, S., and Abboud, H. E. (2003). Calcineurin is activated in diabetes and is required for glomerular hypertrophy and ECM accumulation. Am. J. Physiol. Renal Physiol. 284, F144-F154; Reddy, R. N., Knotts, T. L., Roberts, B. R., Molkentin, J. D., Price, S. R., and Gooch, J. L. (2011). Calcineurin Aβ is required for hypertrophy but not matrix expansion in the diabetic kidney. J. Cell Mol. Med. 15, 414-422). Because studies have also implicated the reactive oxygen species-generating enzymes NADPH oxidases (Nox) in diabetic kidney responses, we tested the hypothesis that Nox and Cn cooperate in a common signaling pathway. First, we examined the role of the two main isoforms of Cn in hypertrophic signaling. Using primary kidney cells lacking a catalytic subunit of Cn (CnAα(-/-) or CnAβ(-/-)), we found that high glucose selectively activates CnAβ, whereas CnAα is constitutively active. Furthermore, CnAβ but not CnAα mediates hypertrophy. Next, we found that chronic reactive oxygen species generation in response to high glucose is attenuated in CnAβ(-/-) cells, suggesting that Cn is upstream of Nox. Consistent with this, loss of CnAβ reduces basal expression and blocks high glucose induction of Nox2 and Nox4. Inhibition of nuclear factor of activated T cells (NFAT), a CnAβ-regulated transcription factor, decreases Nox2 and Nox4 expression, whereas NFAT overexpression increases Nox2 and Nox4, indicating that the CnAβ/NFAT pathway modulates Nox. These data reveal that the CnAβ/NFAT pathway regulates Nox and plays an important role in high glucose-mediated hypertrophic responses in the kidney.
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Affiliation(s)
- Clintoria R Williams
- From the Atlanta Veterans Administration Medical Center, Atlanta, Georgia 30033 and
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182
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Holterman CE, Thibodeau JF, Towaij C, Gutsol A, Montezano AC, Parks RJ, Cooper ME, Touyz RM, Kennedy CRJ. Nephropathy and elevated BP in mice with podocyte-specific NADPH oxidase 5 expression. J Am Soc Nephrol 2013; 25:784-97. [PMID: 24262797 DOI: 10.1681/asn.2013040371] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
NADPH oxidase (Nox) enzymes are a significant source of reactive oxygen species, which contribute to glomerular podocyte dysfunction. Although studies have implicated Nox1, -2, and -4 in several glomerulopathies, including diabetic nephropathy, little is known regarding the role of Nox5 in this context. We examined Nox5 expression and regulation in kidney biopsies from diabetic patients, cultured human podocytes, and a novel mouse model. Nox5 expression increased in human diabetic glomeruli compared with nondiabetic glomeruli. Stimulation with angiotensin II upregulated Nox5 expression in human podocyte cultures and increased reactive oxygen species generation. siRNA-mediated Nox5 knockdown inhibited angiotensin II-stimulated production of reactive oxygen species and altered podocyte cytoskeletal dynamics, resulting in an Rac-mediated motile phenotype. Because the Nox5 gene is absent in rodents, we generated transgenic mice expressing human Nox5 in a podocyte-specific manner (Nox5(pod+)). Nox5(pod+) mice exhibited early onset albuminuria, podocyte foot process effacement, and elevated systolic BP. Subjecting Nox5(pod+) mice to streptozotocin-induced diabetes further exacerbated these changes. Our data show that renal Nox5 is upregulated in human diabetic nephropathy and may alter filtration barrier function and systolic BP through the production of reactive oxygen species. These findings provide the first evidence that podocyte Nox5 has an important role in impaired renal function and hypertension.
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Affiliation(s)
- Chet E Holterman
- Kidney Research Centre, Division of Nephrology, Department of Medicine, and
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183
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Das R, Xu S, Quan X, Nguyen TT, Kong ID, Chung CH, Lee EY, Cha SK, Park KS. Upregulation of mitochondrial Nox4 mediates TGF-β-induced apoptosis in cultured mouse podocytes. Am J Physiol Renal Physiol 2013; 306:F155-67. [PMID: 24259511 DOI: 10.1152/ajprenal.00438.2013] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Injury to podocytes leads to the onset of chronic renal diseases characterized by proteinuria. Elevated transforming growth factor (TGF)-β in kidney tissue is associated with podocyte damage that ultimately results in apoptosis and detachment. We investigated the proapoptotic mechanism of TGF-β in immortalized mouse podocytes. Exogenous TGF-β1-induced podocyte apoptosis through caspase-3 activation, which was related to elevated ROS levels generated by selective upregulation of NADPH oxidase 4 (Nox4). In mouse podocytes, Nox4 was predominantly localized to mitochondria, and Nox4 upregulation by TGF-β1 markedly depolarized mitochondrial membrane potential. TGF-β1-induced ROS production and caspase activation were mitigated by an antioxidant, the Nox inhibitor diphenyleneiodonium, or small interfering RNA for Nox4. A TGF-β receptor I blocker, SB-431542, completely reversed the changes triggered by TGF-β1. Knockdown of either Smad2 or Smad3 prevented the increase of Nox4 expression, ROS generation, loss of mitochondrial membrane potential, and caspase-3 activation by TGF-β1. These results suggest that TGF-β1-induced mitochondrial Nox4 upregulation via the TGF-β receptor-Smad2/3 pathway is responsible for ROS production, mitochondrial dysfunction, and apoptosis, which may at least in part contribute to the development and progression of proteinuric glomerular diseases such as diabetic nephropathy.
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Affiliation(s)
- Ranjan Das
- Dept. of Physiology and Institute of Lifestyle Medicine, Yonsei Univ. Wonju College of Medicine, Ilsan-dong, Wonju, Gangwon-Do 220-701, Republic of Korea.
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184
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Role of NADPH oxidase-mediated reactive oxygen species in podocyte injury. BIOMED RESEARCH INTERNATIONAL 2013; 2013:839761. [PMID: 24319690 PMCID: PMC3844218 DOI: 10.1155/2013/839761] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 09/16/2013] [Accepted: 10/04/2013] [Indexed: 02/07/2023]
Abstract
Proteinuria is an independent risk factor for end-stage renal disease (ESRD) (Shankland, 2006). Recent studies highlighted the mechanisms of podocyte injury and implications for potential treatment strategies in proteinuric kidney diseases (Zhang et al., 2012). Reactive oxygen species (ROS) are cellular signals which are closely associated with the development and progression of glomerular sclerosis. NADPH oxidase is a district enzymatic source of cellular ROS production and prominently expressed in podocytes (Zhang et al., 2010). In the last decade, it has become evident that NADPH oxidase-derived ROS overproduction is a key trigger of podocyte injury, such as renin-angiotensin-aldosterone system activation (Whaley-Connell et al., 2006), epithelial-to-mesenchymal transition (Zhang et al., 2011), and inflammatory priming (Abais et al., 2013). This review focuses on the mechanism of NADPH oxidase-mediated ROS in podocyte injury under different pathophysiological conditions. In addition, we also reviewed the therapeutic perspectives of NADPH oxidase in kidney diseases related to podocyte injury.
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185
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Siddiqi FS, Advani A. Endothelial-podocyte crosstalk: the missing link between endothelial dysfunction and albuminuria in diabetes. Diabetes 2013; 62:3647-55. [PMID: 24158990 PMCID: PMC3806598 DOI: 10.2337/db13-0795] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Although diabetes is the most common cause of end-stage renal disease (ESRD) worldwide, most people with diabetic nephropathy will never develop ESRD but will instead die of cardiovascular (CV) disease (CVD). The first evidence of kidney injury in diabetes is often microalbuminuria, itself also an independent risk marker for CVD. Although the two processes are closely associated, the recent failure of antialbuminuric therapies to affect CV outcomes has encouraged a reconsideration of how albuminuria may occur in diabetes and how increased urinary albumin excretion may be indicative of CV risk. The relationship between CVD and urinary albumin content (even within the normal range) is widely considered to reflect the common underlying pathology of endothelial dysfunction. At the same time, recent years have witnessed a growing appreciation that diabetic albuminuria commonly arises from damage to glomerular podocytes, specialized epithelial cells acting as the final barrier to macromolecular flow into the urinary filtrate. These superficially discordant paradigms can be assimilated by the emerging concept of endothelial-podocyte crosstalk across the glomerular filtration barrier, whereby the actions of one type of cell may profoundly influence the function of the other. The bidirectional nature of this paracrine network is illustrated by the actions of the vascular endothelial growth factor-A (VEGF-A)/VEGF receptor-2 and activated protein C systems, among others. Identification of novel mediators of endothelial-podocyte crosstalk may lead to the development of more effective treatments for diabetic nephropathy and its sequelae.
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186
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Shah A, Kumar S, Simon SD, Singh DP, Kumar A. HIV gp120- and methamphetamine-mediated oxidative stress induces astrocyte apoptosis via cytochrome P450 2E1. Cell Death Dis 2013; 4:e850. [PMID: 24113184 PMCID: PMC3824683 DOI: 10.1038/cddis.2013.374] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 08/05/2013] [Accepted: 08/20/2013] [Indexed: 11/09/2022]
Abstract
HIV-1 glycoprotein 120 (gp120) is known to cause neurotoxicity via several mechanisms including production of proinflammatory cytokines/chemokines and oxidative stress. Likewise, drug abuse is thought to have a direct impact on the pathology of HIV-associated neuroinflammation through the induction of proinflammatory cytokines/chemokines and oxidative stress. In the present study, we demonstrate that gp120 and methamphetamine (MA) causes apoptotic cell death by inducing oxidative stress through the cytochrome P450 (CYP) and NADPH oxidase (NOX) pathways. The results showed that both MA and gp120 induced reactive oxygen species (ROS) production in concentration- and time-dependent manners. The combination of gp120 and MA also induced CYP2E1 expression at both mRNA (1.7±0.2- and 2.8±0.3-fold in SVGA and primary astrocytes, respectively) and protein (1.3±0.1-fold in SVGA and 1.4±0.03-fold in primary astrocytes) levels, suggesting the involvement of CYP2E1 in ROS production. This was further confirmed by using a selective inhibitor of CYP2E1, diallylsulfide (DAS), and CYP2E1 knockdown using siRNA, which significantly reduced ROS production (30–60%). As the CYP pathway is known to be coupled with the NOX pathway, including Fenton–Weiss–Haber (FWH) reaction, we examined whether the NOX pathway is also involved in ROS production induced by either gp120 or MA. Our results showed that selective inhibitors of NOX, diphenyleneiodonium (DPI), and FWH reaction, deferoxamine (DFO), also significantly reduced ROS production. These findings were further confirmed using specific siRNAs against NOX2 and NOX4 (NADPH oxidase family). We then showed that gp120 and MA both induced apoptosis (caspase-3 activity and DNA lesion using TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling) assay) and cell death. Furthermore, we showed that DAS, DPI, and DFO completely abolished apoptosis and cell death, suggesting the involvement of CYP and NOX pathways in ROS-mediated apoptotic cell death. In conclusion, this is the first report on the involvement of CYP and NOX pathways in gp120/MA-induced oxidative stress and apoptotic cell death in astrocytes, which has clinical implications in neurodegenerative diseases, including neuroAIDS.
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Affiliation(s)
- A Shah
- Division of Pharmacology and Toxicology, School of Pharmacy, University of Missouri-Kansas City, Kansas City, MO, USA
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187
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Piwkowska A, Rogacka D, Audzeyenka I, Angielski S, Jankowski M. High glucose increases glomerular filtration barrier permeability by activating protein kinase G type Iα subunits in a Nox4-dependent manner. Exp Cell Res 2013; 320:144-52. [PMID: 24041960 DOI: 10.1016/j.yexcr.2013.09.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 09/04/2013] [Accepted: 09/06/2013] [Indexed: 11/29/2022]
Abstract
Hyperglycemia is a primary factor that disturbs podocyte function in the glomerular filtration process; this disturbance leads to the development of diabetic nephropathy, and ultimately, renal failure. Podocyte function may also be altered by biological agents that modify protein kinase activity, including the cGMP-activated protein kinase type Iα (PKGIα). We hypothesized that hyperglycemia-induced podocyte protein hyperpermeability was dependent on PKGIα activation, and that PKGIα was activated via dimerization induced by reactive oxygen species. This hypothesis was investigated in rat podocytes cultured in high glucose (HG, 30 mM). Protein expression was measured with Western blot and immunofluorescence. Podocyte permeability was measured with a transmembrane albumin flux assay. We found that HG increased podocyte permeability in long-term incubations (1, 3, and 5 days); permeability was increased by 66% on day 5. This effect was abolished with apocynin, a NAD(P)H inhibitor, and Rp-8-Br-cGMPS, a PKG inhibitor. It was also abolished by introducing small interfering RNAs (siRNAs) against Nox4 and PKGIα into cultured podocytes. Furthermore, HG increased PKGIα dimerization by 138% (0.23 ± 0.04 vs. 0.54 ± 0.09; P<0.05); this effect was abolished with a siRNA against Nox4. Our observations suggested that HG could increase albumin permeability across the podocyte filtration barrier via Nox4-dependent PKGIα dimerization.
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Affiliation(s)
- Agnieszka Piwkowska
- Mossakowski Medical Research Centre Polish Academy of Sciences, Laboratory of Molecular and Cellular Nephrology Dębinki 7, Gdańsk 80-211, Poland.
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188
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20-HETE and EETs in diabetic nephropathy: a novel mechanistic pathway. PLoS One 2013; 8:e70029. [PMID: 23936373 PMCID: PMC3732284 DOI: 10.1371/journal.pone.0070029] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 06/19/2013] [Indexed: 11/20/2022] Open
Abstract
Diabetic nephropathy (DN), a major complication of diabetes, is characterized by hypertrophy, extracellular matrix accumulation, fibrosis and proteinuria leading to loss of renal function. Hypertrophy is a major factor inducing proximal tubular epithelial cells injury. However, the mechanisms leading to tubular injury is not well defined. In our study, we show that exposure of rats proximal tubular epithelial cells to high glucose (HG) resulted in increased extracellular matrix accumulation and hypertrophy. HG treatment increased ROS production and was associated with alteration in CYPs 4A and 2C11 expression concomitant with alteration in 20-HETE and EETs formation. HG-induced tubular injury were blocked by HET0016, an inhibitor of CYPs 4A. In contrast, inhibition of EETs promoted the effects of HG on cultured proximal tubular cells. Our results also show that alteration in CYPs 4A and 2C expression and 20HETE and EETs formation regulates the activation of the mTOR/p70S6Kinase pathway, known to play a major role in the development of DN. In conclusion, we show that hyperglycemia in diabetes has a significant effect on the expression of Arachidonic Acid (AA)-metabolizing CYPs, manifested by increased AA metabolism, and might thus alter kidney function through alteration of type and amount of AA metabolites.
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189
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Eid AA, Ford BM, Bhandary B, de Cassia Cavaglieri R, Block K, Barnes JL, Gorin Y, Choudhury GG, Abboud HE. Mammalian target of rapamycin regulates Nox4-mediated podocyte depletion in diabetic renal injury. Diabetes 2013; 62:2935-47. [PMID: 23557706 PMCID: PMC3717863 DOI: 10.2337/db12-1504] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Podocyte apoptosis is a critical mechanism for excessive loss of urinary albumin that eventuates in kidney fibrosis. Pharmacological doses of the mammalian target of rapamycin (mTOR) inhibitor rapamycin reduce albuminuria in diabetes. We explored the hypothesis that mTOR mediates podocyte injury in diabetes. High glucose (HG) induces apoptosis of podocytes, inhibits AMP-activated protein kinase (AMPK) activation, inactivates tuberin, and activates mTOR. HG also increases the levels of Nox4 and Nox1 and NADPH oxidase activity. Inhibition of mTOR by low-dose rapamycin decreases HG-induced Nox4 and Nox1, NADPH oxidase activity, and podocyte apoptosis. Inhibition of mTOR had no effect on AMPK or tuberin phosphorylation, indicating that mTOR is downstream of these signaling molecules. In isolated glomeruli of OVE26 mice, there is a similar decrease in the activation of AMPK and tuberin and activation of mTOR with increase in Nox4 and NADPH oxidase activity. Inhibition of mTOR by a small dose of rapamycin reduces podocyte apoptosis and attenuates glomerular injury and albuminuria. Our data provide evidence for a novel function of mTOR in Nox4-derived reactive oxygen species generation and podocyte apoptosis that contributes to urinary albumin excretion in type 1 diabetes. Thus, mTOR and/or NADPH oxidase inhibition may represent a therapeutic modality of diabetic kidney disease.
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Affiliation(s)
- Assaad A Eid
- Department of Medicine, South Texas Veterans Healthcare System and the University of Texas Health Science Center, San Antonio, Texas, USA.
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190
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Gorin Y, Block K. Nox4 and diabetic nephropathy: with a friend like this, who needs enemies? Free Radic Biol Med 2013; 61:130-42. [PMID: 23528476 PMCID: PMC3716866 DOI: 10.1016/j.freeradbiomed.2013.03.014] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 03/12/2013] [Accepted: 03/16/2013] [Indexed: 12/19/2022]
Abstract
Oxidative stress has been linked to the pathogenesis of diabetic nephropathy, a complication of diabetes in the kidney. NADPH oxidases of the Nox family are a major source of reactive oxygen species in the diabetic kidney and are critical mediators of redox signaling in glomerular and tubulointerstitial cells exposed to the diabetic milieu. Here, we present an overview of the current understanding of the roles of Nox catalytic and regulatory subunits in the processes that control mesangial cell, podocyte, and tubulointerstitial cell injury induced by hyperglycemia and other predominant factors enhanced in the diabetic milieu, including the renin-angiotensin system and transforming growth factor-β. The role of the Nox isoform Nox4 in the redox processes that alter renal biology in diabetes is highlighted.
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Affiliation(s)
- Yves Gorin
- Department of Medicine, University of Texas Health Science Center, San Antonio, TX 78229-3900, USA.
| | - Karen Block
- Department of Medicine, University of Texas Health Science Center, San Antonio, TX 78229-3900, USA; Audie L. Murphy Memorial Hospital Division, South Texas Veterans Health Care System, San Antonio, TX 78229, USA.
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191
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Khazim K, Gorin Y, Cavaglieri RC, Abboud HE, Fanti P. The antioxidant silybin prevents high glucose-induced oxidative stress and podocyte injury in vitro and in vivo. Am J Physiol Renal Physiol 2013; 305:F691-700. [PMID: 23804455 DOI: 10.1152/ajprenal.00028.2013] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Podocyte injury, a major contributor to the pathogenesis of diabetic nephropathy, is caused at least in part by the excessive generation of reactive oxygen species (ROS). Overproduction of superoxide by the NADPH oxidase isoform Nox4 plays an important role in podocyte injury. The plant extract silymarin is attributed antioxidant and antiproteinuric effects in humans and in animal models of diabetic nephropathy. We investigated the effect of silybin, the active constituent of silymarin, in cultures of mouse podocytes and in the OVE26 mouse, a model of type 1 diabetes mellitus and diabetic nephropathy. Exposure of podocytes to high glucose (HG) increased 60% the intracellular superoxide production, 90% the NADPH oxidase activity, 100% the Nox4 expression, and 150% the number of apoptotic cells, effects that were completely blocked by 10 μM silybin. These in vitro observations were confirmed by similar in vivo findings. The kidney cortex of vehicle-treated control OVE26 mice displayed greater Nox4 expression and twice as much superoxide production than cortex of silybin-treated mice. The glomeruli of control OVE26 mice displayed 35% podocyte drop out that was not present in the silybin-treated mice. Finally, the OVE26 mice experienced 54% more pronounced albuminuria than the silybin-treated animals. In conclusion, this study demonstrates a protective effect of silybin against HG-induced podocyte injury and extends this finding to an animal model of diabetic nephropathy.
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Affiliation(s)
- Khaled Khazim
- Univ. of Texas Health Science Center, Dept. of Medicine, Division of Nephrology MC 7882, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA
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192
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Abstract
Oxidative stress has been linked to the pathogenesis of the major complications of diabetes in the kidney, the heart, the eye or the vasculature. NADPH oxidases of the Nox family are a major source of ROS (reactive oxygen species) and are critical mediators of redox signalling in cells from different organs afflicted by the diabetic milieu. In the present review, we provide an overview of the current knowledge related to the understanding of the role of Nox in the processes that control cell injury induced by hyperglycaemia and other predominant factors enhanced in diabetes, including the renin–angiotensin system, TGF-β (transforming growth factor-β) and AGEs (advanced glycation end-products). These observations support a critical role for Nox homologues in diabetic complications and indicate that NADPH oxidases are an important therapeutic target. Therefore the design and development of small-molecule inhibitors that selectively block Nox oxidases appears to be a reasonable approach to prevent or retard the complications of diabetes in target organs. The bioefficacy of these agents in experimental animal models is also discussed in the present review.
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193
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Long DA, Kolatsi-Joannou M, Price KL, Dessapt-Baradez C, Huang JL, Papakrivopoulou E, Hubank M, Korstanje R, Gnudi L, Woolf AS. Albuminuria is associated with too few glomeruli and too much testosterone. Kidney Int 2013; 83:1118-29. [PMID: 23447063 PMCID: PMC3674403 DOI: 10.1038/ki.2013.45] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 12/15/2012] [Accepted: 12/21/2012] [Indexed: 12/12/2022]
Abstract
Normally, the glomerular filtration barrier almost completely excludes circulating albumin from entering the urine. Genetic variation and both pre- and postnatal environmental factors may affect albuminuria in humans. Here we determine whether glomerular gene expression in mouse strains with naturally occurring variations in albuminuria would allow identification of proteins deregulated in relatively 'leaky' glomeruli. Albuminuria increased in female B6 to male B6 to female FVB/N to male FVB/N mice, whereas the number of glomeruli/kidney was the exact opposite. Testosterone administration led to increased albuminuria in female B6 but not female FVB/N mice. A common set of 39 genes, many expressed in podocytes, were significantly differentially expressed in each of the four comparisons: male versus female B6 mice, male versus female FVB/N mice, male FVB/N versus male B6 mice, and female FVB/N versus female B6 mice. The transcripts encoded proteins involved in oxidation/reduction reactions, ion transport, and enzymes involved in detoxification. These proteins may represent novel biomarkers and even therapeutic targets for early kidney and cardiovascular disease.
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Affiliation(s)
- David A Long
- Nephro-Urology Unit, UCL Institute of Child Health, London, UK.
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194
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Pichaiwong W, Hudkins KL, Wietecha T, Nguyen TQ, Tachaudomdach C, Li W, Askari B, Kobayashi T, O'Brien KD, Pippin JW, Shankland SJ, Alpers CE. Reversibility of structural and functional damage in a model of advanced diabetic nephropathy. J Am Soc Nephrol 2013; 24:1088-102. [PMID: 23641056 DOI: 10.1681/asn.2012050445] [Citation(s) in RCA: 130] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The reversibility of diabetic nephropathy remains controversial. Here, we tested whether replacing leptin could reverse the advanced diabetic nephropathy modeled by the leptin-deficient BTBR ob/ob mouse. Leptin replacement, but not inhibition of the renin-angiotensin-aldosterone system (RAAS), resulted in near-complete reversal of both structural (mesangial matrix expansion, mesangiolysis, basement membrane thickening, podocyte loss) and functional (proteinuria, accumulation of reactive oxygen species) measures of advanced diabetic nephropathy. Immunohistochemical labeling with the podocyte markers Wilms tumor 1 and p57 identified parietal epithelial cells as a possible source of regenerating podocytes. Thus, the leptin-deficient BTBR ob/ob mouse provides a model of advanced but reversible diabetic nephropathy for further study. These results also suggest that restoration of lost podocytes is possible but is not induced by RAAS inhibition, possibly explaining the limited efficacy of RAAS inhibitors in promoting repair of diabetic nephropathy.
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195
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Yang H, Zhao B, Liao C, Zhang R, Meng K, Xu J, Jiao J. High glucose-induced apoptosis in cultured podocytes involves TRPC6-dependent calcium entry via the RhoA/ROCK pathway. Biochem Biophys Res Commun 2013; 434:394-400. [PMID: 23570668 DOI: 10.1016/j.bbrc.2013.03.087] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 03/29/2013] [Indexed: 10/27/2022]
Abstract
Increasing evidence indicates that podocyte apoptosis is a key event in the development of diabetic nephrology. However, the underlying mechanism of this apoptosis remains poorly understood. In this study, we report that high levels of glucose enhanced the expression of TRPC6 and TRPC6-dependent Ca(2+) influx, but glucose levels did not affect TRPC1 and TRPC5 expression. TRPC6 knockdown by siRNA interference attenuated the observed increase in glucose-induced podocyte apoptosis. High glucose levels also increased the generation of ROS; inhibition of ROS activity by N-acetyl-l-cysteine attenuated the high glucose-induced increase in TRPC6 expression and Ca(2+) influx. Exogenous treatment with H2O2 mimicked the high glucose response, resulting in an increase in TRPC6 expression and Ca(2+) influx. Taken together, these data suggest that high glucose levels induce ROS, thereby mediating TRPC6 expression and Ca(2+) influx. Because RhoA activity is increased following TRPC6 activation, we investigated whether TRPC6 is involved in high glucose-induced apoptosis via the RhoA/ROCK pathway. We report that high glucose levels produced an increase in RhoA activity, and this effect was abolished by the knockdown of TRPC6. Moreover, inhibition of the RhoA/ROCK pathway by a ROCK inhibitor, Y27632, also attenuated high glucose-induced apoptosis. We conclude that TRPC6 is involved in high glucose-induced podocyte apoptosis through the RhoA/ROCK pathway.
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Affiliation(s)
- He Yang
- Department of Nephrology, The Second Affiliated Hospital, Harbin Medical University, PR China
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196
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Li R, Zhang L, Shi W, Zhang B, Liang X, Liu S, Wang W. NFAT2 mediates high glucose-induced glomerular podocyte apoptosis through increased Bax expression. Exp Cell Res 2013; 319:992-1000. [PMID: 23340267 DOI: 10.1016/j.yexcr.2013.01.007] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2012] [Revised: 12/25/2012] [Accepted: 01/07/2013] [Indexed: 01/19/2023]
Abstract
BACKGROUND Hyperglycemia promotes podocyte apoptosis and plays a key role in the pathogenesis of diabetic nephropathy. However, the mechanisms that mediate hyperglycemia-induced podocyte apoptosis is still far from being fully understood. Recent studies reported that high glucose activate nuclear factor of activated T cells (NFAT) in vascular smooth muscle or pancreatic β-cells. Here, we sought to determine if hyperglycemia activates NFAT2 in cultured podocyte and whether this leads to podocyte apoptosis. Meanwhile, we also further explore the mechanisms of NFAT2 activation and NFAT2 mediates high glucose-induced podocyte apoptosis. METHODS Immortalized mouse podocytes were cultured in media containing normal glucose (NG), or high glucose (HG) or HG plus cyclosporine A (a pharmacological inhibitor of calcinerin) or 11R-VIVIT (a special inhibitor of NFAT2). The activation of NFAT2 in podocytes was detected by western blotting and immunofluorescence assay. The role of NFAT2 in hyperglycemia-induced podocyte apoptosis was further evaluated by observing the inhibition of NFAT2 activation by 11R-VIVIT using flow cytometer. Intracellular Ca(2+) was monitored in HG-treated podcocytes using Fluo-3/AM. The mRNA and protein expression of apoptosis gene Bax were measured by real time-qPCR and western blotting. RESULTS HG stimulation activated NFAT2 in a time- and dose-dependent manner in cultured podocytes. Pretreatment with cyclosporine A (500nM) or 11R-VIVIT (100nM) completely blocked NFAT2 nuclear accumulation. Meanwhile, the apoptosis effects induced by HG were also abrogated by concomitant treatment with 11R-VIVIT in cultured podocytes. We further found that HG also increased [Ca(2+)]i, leading to activation of calcineurin, and subsequent increased nuclear accumulation of NFAT2 and Bax expression in cultured podocytes. CONCLUSION Our results identify a new finding that HG-induced podocyte apoptosis is mediated by calcineurin/NFAT2/Bax signaling pathway, which may present a promising target for therapeutic intervention.
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Affiliation(s)
- Ruizhao Li
- Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou 510080, People's Republic of China.
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197
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Hardwick JP, Eckman K, Lee YK, Abdelmegeed MA, Esterle A, Chilian WM, Chiang JY, Song BJ. Eicosanoids in metabolic syndrome. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2013; 66:157-266. [PMID: 23433458 DOI: 10.1016/b978-0-12-404717-4.00005-6] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Chronic persistent inflammation plays a significant role in disease pathology of cancer, cardiovascular disease, and metabolic syndrome (MetS). MetS is a constellation of diseases that include obesity, diabetes, hypertension, dyslipidemia, hypertriglyceridemia, and hypercholesterolemia. Nonalcoholic fatty liver disease (NAFLD) is associated with many of the MetS diseases. These metabolic derangements trigger a persistent inflammatory cascade, which includes production of lipid autacoids (eicosanoids) that recruit immune cells to the site of injury and subsequent expression of cytokines and chemokines that amplify the inflammatory response. In acute inflammation, the transcellular synthesis of antiinflammatory eicosanoids resolve inflammation, while persistent activation of the autacoid-cytokine-chemokine cascade in metabolic disease leads to chronic inflammation and accompanying tissue pathology. Many drugs targeting the eicosanoid pathways have been shown to be effective in the treatment of MetS, suggesting a common linkage between inflammation, MetS and drug metabolism. The cross-talk between inflammation and MetS seems apparent because of the growing evidence linking immune cell activation and metabolic disorders such as insulin resistance, dyslipidemia, and hypertriglyceridemia. Thus modulation of lipid metabolism through either dietary adjustment or selective drugs may become a new paradigm in the treatment of metabolic disorders. This review focuses on the mechanisms linking eicosanoid metabolism to persistent inflammation and altered lipid and carbohydrate metabolism in MetS.
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Affiliation(s)
- James P Hardwick
- Biochemistry and Molecular Pathology, Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, Ohio, USA.
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198
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Li PL, Zhang Y. Cross talk between ceramide and redox signaling: implications for endothelial dysfunction and renal disease. Handb Exp Pharmacol 2013:171-97. [PMID: 23563657 DOI: 10.1007/978-3-7091-1511-4_9] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Recent studies have demonstrated that cross talk between ceramide and redox signaling modulates various cell activities and functions and contributes to the development of cardiovascular diseases and renal dysfunctions. Ceramide triggers the generation of reactive oxygen species (ROS) and increases oxidative stress in many mammalian cells and animal models. On the other hand, inhibition of ROS-generating enzymes or treatment of antioxidants impairs sphingomyelinase activation and ceramide production. As a mechanism, ceramide-enriched signaling platforms, special cell membrane rafts (MR) (formerly lipid rafts), provide an important microenvironment to mediate the cross talk of ceramide and redox signaling to exert a corresponding regulatory role on cell and organ functions. In this regard, activation of acid sphingomyelinase and generation of ceramide mediate the formation of ceramide-enriched membrane platforms, where transmembrane signals are transmitted or amplified through recruitment, clustering, assembling, or integration of various signaling molecules. A typical such signaling platform is MR redox signaling platform that is centered on ceramide production and aggregation leading to recruitment and assembling of NADPH oxidase to form an active complex in the cell plasma membrane. This redox signaling platform not only conducts redox signaling or regulation but also facilitates a feedforward amplification of both ceramide and redox signaling. In addition to this membrane MR redox signaling platform, the cross talk between ceramide and redox signaling may occur in other cell compartments. This book chapter focuses on the molecular mechanisms, spatial-temporal regulations, and implications of this cross talk between ceramide and redox signaling, which may provide novel insights into the understanding of both ceramide and redox signaling pathways.
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Affiliation(s)
- Pin-Lan Li
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA.
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199
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Hagiwara S, McClelland A, Kantharidis P. MicroRNA in diabetic nephropathy: renin angiotensin, aGE/RAGE, and oxidative stress pathway. J Diabetes Res 2013; 2013:173783. [PMID: 24575418 PMCID: PMC3875101 DOI: 10.1155/2013/173783] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 11/14/2013] [Indexed: 01/13/2023] Open
Abstract
MicroRNAs (miRNA) are a novel class of small, noncoding RNA molecules that have gained the attention of many researchers in recent years due to their ability to posttranscriptionally regulate the expression of families of genes simultaneously. Their role in normal physiology and pathobiology is intriguing and their regulation in normal and disease states is fascinating. That the cells can return to a state of homeostasis when these small molecules are perturbed is truly remarkable given the multiple cellular targets of each miRNA and that many mRNAs are targeted by multiple miRNAs. Several reviews have covered aspects of miRNA function in biology and disease. Here, we review the role of miRNA in regulating the renin-angiotensin system, AGE/RAGE signalling, and under conditions of oxidative stress in the context of diabetic nephropathy.
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Affiliation(s)
- Shinji Hagiwara
- JDRF Danielle Alberti Memorial Centre for Diabetes Complications, Diabetes Division, Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia
- Division of Nephrology, Department of Internal Medicine, Faculty of Medicine, Juntendo University, Tokyo 113-8421, Japan
| | - Aaron McClelland
- JDRF Danielle Alberti Memorial Centre for Diabetes Complications, Diabetes Division, Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia
| | - Phillip Kantharidis
- JDRF Danielle Alberti Memorial Centre for Diabetes Complications, Diabetes Division, Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia
- *Phillip Kantharidis:
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200
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Vashistha H, Singhal PC, Malhotra A, Husain M, Mathieson P, Saleem MA, Kuriakose C, Seshan S, Wilk A, Delvalle L, Peruzzi F, Giorgio M, Pelicci PG, Smithies O, Kim HS, Kakoki M, Reiss K, Meggs LG. Null mutations at the p66 and bradykinin 2 receptor loci induce divergent phenotypes in the diabetic kidney. Am J Physiol Renal Physiol 2012; 303:F1629-40. [PMID: 23019230 PMCID: PMC3532473 DOI: 10.1152/ajprenal.00246.2012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 09/25/2012] [Indexed: 12/28/2022] Open
Abstract
Candidate genes have been identified that confer increased risk for diabetic glomerulosclerosis (DG). Mice heterozygous for the Akita (Ins2(+/C96Y)) diabetogenic mutation with a second mutation introduced at the bradykinin 2 receptor (B2R(-/-)) locus express a disease phenotype that approximates human DG. Src homology 2 domain transforming protein 1 (p66) controls mitochondrial metabolism and cellular responses to oxidative stress, aging, and apoptosis. We generated p66-null Akita mice to test whether inactivating mutations at the p66 locus will rescue kidneys of Akita mice from disease-causing mutations at the Ins2 and B2R loci. Here we show null mutations at the p66 and B2R loci interact with the Akita (Ins2(+/C96Y)) mutation, independently and in combination, inducing divergent phenotypes in the kidney. The B2R(-/-) mutation induces detrimental phenotypes, as judged by increased systemic and renal levels of oxidative stress, histology, and urine albumin excretion, whereas the p66-null mutation confers a powerful protection phenotype. To elucidate the mechanism(s) of the protection phenotype, we turned to our in vitro system. Experiments with cultured podocytes revealed previously unrecognized cross talk between p66 and the redox-sensitive transcription factor p53 that controls hyperglycemia-induced ROS metabolism, transcription of p53 target genes (angiotensinogen, angiotensin II type-1 receptor, and bax), angiotensin II generation, and apoptosis. RNA-interference targeting p66 inhibits all of the above. Finally, protein levels of p53 target genes were upregulated in kidneys of Akita mice but unchanged in p66-null Akita mice. Taken together, p66 is a potential molecular target for therapeutic intervention in DG.
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Affiliation(s)
- Himanshu Vashistha
- Institute for Translational Research, Nephrology Research Laboratory, Ochsner Health Foundation, Dept. of Nephrology, New Orleans, LA 70121, USA
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