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Chen YL, Ren Y, Rosa RH, Kuo L, Hein TW. Contributions of Sodium-Hydrogen Exchanger 1 and Mitogen-Activated Protein Kinases to Enhanced Retinal Venular Constriction to Endothelin-1 in Diabetes. Diabetes 2021; 70:2353-2363. [PMID: 34353852 PMCID: PMC8576499 DOI: 10.2337/db20-0889] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 07/28/2021] [Indexed: 11/13/2022]
Abstract
Diabetes elevates endothelin-1 (ET-1) in the vitreous and enhances constriction of retinal venules to this peptide. However, mechanisms contributing to ET-1-induced constriction of retinal venules are incompletely understood. We examined roles of sodium-hydrogen exchanger 1 (NHE1), protein kinase C (PKC), mitogen-activated protein kinases (MAPKs), and extracellular calcium (Ca2+) in retinal venular constriction to ET-1 and the impact of diabetes on these signaling molecules. Retinal venules were isolated from control pigs and pigs with streptozocin-induced diabetes for in vitro studies. ET-1-induced vasoconstriction was abolished in the absence of extracellular Ca2+ and sensitive to c-Jun N-terminal kinase (JNK) inhibitor SP600125 but unaffected by extracellular signal-regulated kinase (ERK) inhibitor PD98059, p38 kinase inhibitor SB203580, or broad-spectrum PKC inhibitor Gö 6983. Diabetes (after 2 weeks) enhanced venular constriction to ET-1, which was insensitive to PD98059 and Gö 6983 but was prevented by NHE1 inhibitor cariporide, SB203580, and SP600125. In conclusion, extracellular Ca2+ entry and activation of JNK, independent of ERK and PKC, mediate constriction of retinal venules to ET-1. Diabetes activates p38 MAPK and NHE1, which cause enhanced venular constriction to ET-1. Treatments targeting these vascular molecules may lessen retinal complications in early diabetes.
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Affiliation(s)
- Yen-Lin Chen
- Department of Medical Physiology, College of Medicine, Texas A&M University Health Science Center, Bryan, TX
| | - Yi Ren
- Department of Medical Physiology, College of Medicine, Texas A&M University Health Science Center, Bryan, TX
| | - Robert H Rosa
- Department of Medical Physiology, College of Medicine, Texas A&M University Health Science Center, Bryan, TX
- Department of Ophthalmology, Baylor Scott & White Eye Institute, Temple, TX
| | - Lih Kuo
- Department of Medical Physiology, College of Medicine, Texas A&M University Health Science Center, Bryan, TX
| | - Travis W Hein
- Department of Medical Physiology, College of Medicine, Texas A&M University Health Science Center, Bryan, TX
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2
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Patel DM, Bose M, Cooper ME. Glucose and Blood Pressure-Dependent Pathways-The Progression of Diabetic Kidney Disease. Int J Mol Sci 2020; 21:ijms21062218. [PMID: 32210089 PMCID: PMC7139394 DOI: 10.3390/ijms21062218] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 03/17/2020] [Accepted: 03/17/2020] [Indexed: 12/11/2022] Open
Abstract
The major clinical associations with the progression of diabetic kidney disease (DKD) are glycemic control and systemic hypertension. Recent studies have continued to emphasize vasoactive hormone pathways including aldosterone and endothelin which suggest a key role for vasoconstrictor pathways in promoting renal damage in diabetes. The role of glucose per se remains difficult to define in DKD but appears to involve key intermediates including reactive oxygen species (ROS) and dicarbonyls such as methylglyoxal which activate intracellular pathways to promote fibrosis and inflammation in the kidney. Recent studies have identified a novel molecular interaction between hemodynamic and metabolic pathways which could lead to new treatments for DKD. This should lead to a further improvement in the outlook of DKD building on positive results from RAAS blockade and more recently newer classes of glucose-lowering agents such as SGLT2 inhibitors and GLP1 receptor agonists.
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Affiliation(s)
- Devang M. Patel
- Department of Diabetes, Monash University Central, Clinical School, Melbourne, VIC 3004, Australia;
- Correspondence: (D.M.P.); (M.E.C.)
| | - Madhura Bose
- Department of Diabetes, Monash University Central, Clinical School, Melbourne, VIC 3004, Australia;
| | - Mark E. Cooper
- Department of Diabetes, Monash University Central, Clinical School, Melbourne, VIC 3004, Australia;
- Department of Endocrinology and Diabetes, The Alfred Hospital, Melbourne, VIC 3004, Australia
- Correspondence: (D.M.P.); (M.E.C.)
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3
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Sheu ML, Shen CC, Jheng JR, Chiang CK. Activation of PI3K in response to high glucose leads to regulation of SOCS-3 and STAT1/3 signals and induction of glomerular mesangial extracellular matrix formation. Oncotarget 2017; 8:16925-16938. [PMID: 28129651 PMCID: PMC5370011 DOI: 10.18632/oncotarget.14808] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 12/13/2016] [Indexed: 01/27/2023] Open
Abstract
Excessive deposition of extracellular matrix (ECM) in the glomerulus contributed by mesangial cells is the hallmark of diabetic nephropathy, eventually leading to glomerulosclerosis. In this study, we examined the regulatory signals involved in the high glucose (HG)-induced overproduction of ECM in rat mesangial cells (RMCs). We disclosed excessive fibronectin and collagen IV production, tyrosine phosphorylation of signal transducer and activator of transcription 1 and 3 (STAT1/3), and up-regulation of suppressor of cytokine signaling-3 (SOCS-3) expression in HG-treated RMCs. STAT1/STAT3 binding element was essential for SOCS-3 promoter activity stimulated by HG. HG was capable of promoting the specific DNA binding activities to an oligonucleotide probe containing the SOCS-3 sequence. The selective phosphoinositide 3-kinase (PI3K) inhibitor LY294002 and dominant negative p85 vector (DNΔp85) transfection effectively abolished these HG-induced responses. Moreover, HG markedly increased the cyclin kinase inhibitor p27Kip1 protein expression, which could be inhibited by LY294002 or transfection of DNΔp85. Taken together, these results suggest that HG-induced SOCS-3 upregulation depends upon the presence of STAT-binding element in the SOCS-3 promoter, which is specifically activated by STAT1/3. The PI3K/STAT1/3 signaling pathway mediated HG-triggered ECM accumulation and SOCS-3 upregulation in RMCs.
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Affiliation(s)
- Meei-Ling Sheu
- Department of Medical Research, Taichung Veterans General Hospital, Taichung, Taiwan.,Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan.,Rong Hsing Research Center for Translational Medicine, National Chung Hsing University, Taichung, Taiwan
| | - Chin-Chang Shen
- Chemical Engineering Division, Institute of Nuclear Energy Research, Atomic Energy Council, Taoyuan, Taiwan
| | - Jia-Rong Jheng
- Institute of Toxicology, National Taiwan University College of Medicine, Taipei, Taiwan.,Department of Internal Medicine, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Chih-Kang Chiang
- Institute of Toxicology, National Taiwan University College of Medicine, Taipei, Taiwan.,Department of Internal Medicine, National Taiwan University College of Medicine, Taipei, Taiwan.,Department of Integrated Diagnostics & Therapeutics, National Taiwan University Hospital, Taipei, Taiwan
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4
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Qiao Y, Gao K, Wang Y, Wang X, Cui B. Resveratrol ameliorates diabetic nephropathy in rats through negative regulation of the p38 MAPK/TGF-β1 pathway. Exp Ther Med 2017; 13:3223-3230. [PMID: 28588674 PMCID: PMC5450784 DOI: 10.3892/etm.2017.4420] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 01/20/2017] [Indexed: 12/25/2022] Open
Abstract
Resveratrol (RSV) has been shown to have a renoprotective effect against diabetic nephropathy, but the underlying mechanisms of this have not been fully elucidated. The aim of the current study was to explore the mechanisms responsible for the therapeutic effects of RSV in rat mesangial cells in vitro and in a rat model of diabetic nephropathy. The viability of CRL-2573 rat mesangial cells and their expression levels of p38, phosphorylated (p)-p38, transforming growth factor beta 1 (TGF-β1) and fibronectin were assessed in response to treatment with high glucose, with or without RSV. Diabetic nephropathy was also induced in Sprague-Dawley rats by streptozotocin treatment. At 8 weeks, basic biochemical parameters and histopathological abnormalities as well as the expression of p38, p-p38, TGF-β1 and fibronectin in rat kidneys were compared between control diabetic rats and those treated with 20 mg/kg RSV daily for 4 weeks. In the mesangial cell line, RSV inhibited high glucose-induced increases in cell viability and fibronectin expression by significantly reducing p38 mitogen-activated protein kinase (MAPK) activation and TGF-β1 expression (P<0.05). In diabetic rats, RSV significantly decreased blood glucose, serum creatinine and urinary albumin levels, as well as the kidney weight and ratio of kidney weight/body weight compared with the control group (P<0.05). Moreover, RSV ameliorated renal histological changes and downregulated the expression of p-p38, TGF-β1 and fibronectin in the kidneys of diabetic rats. These data suggested that RSV protected renal tissue from diabetes-induced injury and that this activity may be via inhibition of the p38 MAPK/TGF-β1 signaling pathway.
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Affiliation(s)
- Yuan Qiao
- Department of Endocrinology, Shaanxi Provincial Hospital, Xi'an, Shaanxi 710068, P.R. China
| | - Ke Gao
- Department of Neurosurgery, The First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi 710061, P.R. China
| | - Yangwei Wang
- Department of Endocrinology, Shaanxi Provincial Hospital, Xi'an, Shaanxi 710068, P.R. China
| | - Xueliang Wang
- Department of Public Health, College of Public Health, Health Science Center, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Bo Cui
- Department of Endocrinology, The First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi 710061, P.R. China
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Witzel II, Jelinek HF, Khalaf K, Lee S, Khandoker AH, Alsafar H. Identifying Common Genetic Risk Factors of Diabetic Neuropathies. Front Endocrinol (Lausanne) 2015; 6:88. [PMID: 26074879 PMCID: PMC4447004 DOI: 10.3389/fendo.2015.00088] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 05/13/2015] [Indexed: 12/13/2022] Open
Abstract
Type 2 diabetes mellitus (T2DM) is a global public health problem of epidemic proportions, with 60-70% of affected individuals suffering from associated neurovascular complications that act on multiple organ systems. The most common and clinically significant neuropathies of T2DM include uremic neuropathy, peripheral neuropathy, and cardiac autonomic neuropathy. These conditions seriously impact an individual's quality of life and significantly increase the risk of morbidity and mortality. Although advances in gene sequencing technologies have identified several genetic variants that may regulate the development and progression of T2DM, little is known about whether or not the variants are involved in disease progression and how these genetic variants are associated with diabetic neuropathy specifically. Significant missing heritability data and complex disease etiologies remain to be explained. This article is the first to provide a review of the genetic risk variants implicated in the diabetic neuropathies and to highlight potential commonalities. We thereby aim to contribute to the creation of a genetic-metabolic model that will help to elucidate the cause of diabetic neuropathies, evaluate a patient's risk profile, and ultimately facilitate preventative and targeted treatment for the individual.
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Affiliation(s)
- Ini-Isabée Witzel
- Biomedical Engineering Department, Khalifa University of Science, Technology and Research, Abu Dhabi, United Arab Emirates
| | - Herbert F. Jelinek
- Australian School of Advanced Medicine, Macquarie University, Sydney, NSW, Australia
- Centre for Research in Complex Systems, School of Community Health, Charles Sturt University, Albury, NSW, Australia
| | - Kinda Khalaf
- Biomedical Engineering Department, Khalifa University of Science, Technology and Research, Abu Dhabi, United Arab Emirates
| | - Sungmun Lee
- Biomedical Engineering Department, Khalifa University of Science, Technology and Research, Abu Dhabi, United Arab Emirates
| | - Ahsan H. Khandoker
- Biomedical Engineering Department, Khalifa University of Science, Technology and Research, Abu Dhabi, United Arab Emirates
- Electrical and Electronic Engineering Department, The University of Melbourne, Parkville, VIC, Australia
| | - Habiba Alsafar
- Biomedical Engineering Department, Khalifa University of Science, Technology and Research, Abu Dhabi, United Arab Emirates
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Abstract
The high prevalence of vitamin D deficiency in patients with chronic kidney disease is believed to be an important risk factor for the cardiorenal syndrome commonly seen in this patient population. African Americans suffer a disproportionally high incidence of renal and cardiovascular disease with poor disease outcome, which may be partly attributed to their low vitamin D status in part owing to low subcutaneous photoproduction of vitamin D. Mounting evidence from animal and clinical studies has shown beneficial effects of vitamin D therapy on the renal and cardiovascular systems, and the underlying renoprotective and cardioprotective mechanisms of vitamin D receptor (VDR)-mediated signaling are under intense investigation. In this article, our most recent understanding of the renal protective mechanism of the podocyte VDR signaling against diabetic nephropathy and the anti-atherosclerotic role of macrophage VDR signaling in the regulation of atherosclerosis is reviewed.
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Affiliation(s)
- Yan Chun Li
- Department of Medicine, The University of Chicago, Chicago, IL.
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7
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Lenoir O, Milon M, Virsolvy A, Hénique C, Schmitt A, Massé JM, Kotelevtsev Y, Yanagisawa M, Webb DJ, Richard S, Tharaux PL. Direct action of endothelin-1 on podocytes promotes diabetic glomerulosclerosis. J Am Soc Nephrol 2014; 25:1050-62. [PMID: 24722437 DOI: 10.1681/asn.2013020195] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The endothelin system has emerged as a novel target for the treatment of diabetic nephropathy. Endothelin-1 promotes mesangial cell proliferation and sclerosis. However, no direct pathogenic effect of endothelin-1 on podocytes has been shown in vivo and endothelin-1 signaling in podocytes has not been investigated. This study investigated endothelin effects in podocytes during experimental diabetic nephropathy. Stimulation of primary mouse podocytes with endothelin-1 elicited rapid calcium transients mediated by endothelin type A receptors (ETARs) and endothelin type B receptors (ETBRs). We then generated mice with a podocyte-specific double deletion of ETAR and ETBR (NPHS2-Cre×Ednra(lox/lox)×Ednrb(lox/lox) [Pod-ETRKO]). In vitro, treatment with endothelin-1 increased total β-catenin and phospho-NF-κB expression in wild-type glomeruli, but this effect was attenuated in Pod-ETRKO glomeruli. After streptozotocin injection to induce diabetes, wild-type mice developed mild diabetic nephropathy with microalbuminuria, mesangial matrix expansion, glomerular basement membrane thickening, and podocyte loss, whereas Pod-ETRKO mice presented less albuminuria and were completely protected from glomerulosclerosis and podocyte loss, even when uninephrectomized. Moreover, glomeruli from normal and diabetic Pod-ETRKO mice expressed substantially less total β-catenin and phospho-NF-κB compared with glomeruli from counterpart wild-type mice. This evidence suggests that endothelin-1 drives development of glomerulosclerosis and podocyte loss through direct activation of endothelin receptors and NF-κB and β-catenin pathways in podocytes. Notably, both the expression and function of the ETBR subtype were found to be important. Furthermore, these results indicate that activation of the endothelin-1 pathways selectively in podocytes mediates pathophysiologic crosstalk that influences mesangial architecture and sclerosis.
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Affiliation(s)
- Olivia Lenoir
- Paris Cardiovascular Research Centre, Institut National de la Santé et de la Recherche Médicale, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Marine Milon
- Paris Cardiovascular Research Centre, Institut National de la Santé et de la Recherche Médicale, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Anne Virsolvy
- Physiologie et Médecine expérimentale du Cœur et des Muscles, Institut National de la Santé et de la Recherche Médicale U1046, Université Montpellier 1, Université Montpellier 2, Montpellier, France
| | - Carole Hénique
- Paris Cardiovascular Research Centre, Institut National de la Santé et de la Recherche Médicale, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Alain Schmitt
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France; Transmission Electron Microscopy Platform, Institut National de la Santé et de la Recherche Médicale U1016, Cochin Institut, Paris, France; Centre National de la Recherche Scientifique UMR81044, Paris, France
| | - Jean-Marc Massé
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France; Transmission Electron Microscopy Platform, Institut National de la Santé et de la Recherche Médicale U1016, Cochin Institut, Paris, France; Centre National de la Recherche Scientifique UMR81044, Paris, France
| | - Yuri Kotelevtsev
- The Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom; Pushchino State Institute for Natural Sciences, Pushchino, Moscow Region, Russian Federation
| | | | - David J Webb
- The Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Sylvain Richard
- Physiologie et Médecine expérimentale du Cœur et des Muscles, Institut National de la Santé et de la Recherche Médicale U1046, Université Montpellier 1, Université Montpellier 2, Montpellier, France
| | - Pierre-Louis Tharaux
- Paris Cardiovascular Research Centre, Institut National de la Santé et de la Recherche Médicale, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France; Nephrology Service, Georges Pompidou European Hospital, Assistance Publique Hopitaux de Paris, Paris, France
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8
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Xiao J, Gao H, Jin Y, Zhao Z, Guo J, Liu Z, Zhao Z. The abnormal expressions of tristetraprolin and the VEGF family in uraemic rats with peritoneal dialysis. Mol Cell Biochem 2014; 392:229-38. [PMID: 24696420 DOI: 10.1007/s11010-014-2033-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 03/14/2014] [Indexed: 01/01/2023]
Abstract
The effect of peritoneal dialysis (PD) with high-glucose dialysis fluid on the VEGF family, tristetraprolin (TTP), angiogenesis and lymphangiogenesis was investigated. Forty male SD rats were randomised into five groups: normal group, sham operation group, uraemia group, PD 2-week group and PD4-week group. After 4 weeks of PD, microvessel density (MVD) and lymphatic vessel density (LVD) were measured. The expressions of both the VEGF family and TTP were detected. Compared with the normal group, the mRNA expression levels of the VEGF family were significantly increased in the uraemia group (P < 0.05), and also in the PD 2-week group and PD4-week group (P < 0.05) compared with uraemia group. The mRNAs of VEGF-A and VEGF-C in 4-week PD group likewise were significantly increased compared with the 2-week PD group. However, the mRNA expression of TTP was significantly decreased in the uraemia group compared with the normal group (P < 0.05), and also in the PD group compared with the uraemia group (P < 0.05). Compared with the normal group, the protein expressions of TTP were significantly decreased in the uraemia group (P < 0.05), and also in the PD group compared with the uraemia group (P < 0.05). Compared with the normal group, the MVD and LVD counts were gradually increased in the PD group, which was associated with PD time. In addition, the expression of TTP gradually decreased over PD time. High-glucose PD fluid and uraemic circumstance resulted in the abnormal expression of TTP and the VEGF family in a PD time-dependent manner; this may lead to UFF through angiogenesis and lymphangiogenesis.
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Affiliation(s)
- Jing Xiao
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, No.1 Eastern Jianshe Road, Zhengzhou, 450052, Henan, China
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9
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Zhu S, Yang Y, Hu J, Qian L, Jiang Y, Li X, Yang Q, Bai H, Chen Q. Wld(S) ameliorates renal injury in a type 1 diabetic mouse model. Am J Physiol Renal Physiol 2014; 306:F1348-56. [PMID: 24598800 DOI: 10.1152/ajprenal.00418.2013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Diabetic nephropathy (DN) is the leading cause of end-stage kidney disease worldwide. The purpose of this study is to investigate whether the Wld(S) (slow Wallerian degeneration; also known as Wld) gene plays a renoprotective role during the progression of DN. Diabetes was induced in 8-wk-old male wild-type (WT) and C57BL/Wld(S) mice by streptozotocin (STZ) injection. Blood and urinary variables including blood glucose, glycated hemoglobin (GHb), insulin, urea nitrogen, and albumin/creatinine ratio were assessed 4, 7, and 14 wk after STZ injection. Periodic acid-Schiff staining, Masson staining, and silver staining were performed for renal pathological analyses. In addition, the renal ultrastructure was observed by electron microscope. The activities of p38 and ERK signaling in renal cortical tissues were evaluated by Western blotting. NAD(+)/NADH ratio and NADPH oxidase activity were also measured. Moreover, the expressions of TNF-α, IL-1, and IL-6 were examined. We provide experimental evidence demonstrating that the Wld(S) gene is expressed in kidney cells and protects against the early stage of diabetes-induced renal dysfunction and extracellular matrix accumulation through delaying the reduction of the NAD(+)/NADH ratio, inhibiting the activation of p38 and ERK signaling, and suppressing oxidative stress as evidenced by the decreased NADPH oxidase activity and lower expression of TNF-α, IL-1, and IL-6.
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Affiliation(s)
- Shuaishuai Zhu
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
| | - Yelin Yang
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
| | - Jin Hu
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
| | - Lingling Qian
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
| | - Yuchen Jiang
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
| | - Xiaoyu Li
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
| | - Qing Yang
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
| | - Hui Bai
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
| | - Qi Chen
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
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10
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Abstract
Diabetes mellitus contributes greatly to morbidity, mortality, and overall health care costs. In major part, these outcomes derive from the high incidence of progressive kidney dysfunction in patients with diabetes making diabetic nephropathy a leading cause of end-stage renal disease. A better understanding of the molecular mechanism involved and of the early dysfunctions observed in the diabetic kidney may permit the development of new strategies to prevent diabetic nephropathy. Here we review the pathophysiological changes that occur in the kidney in response to hyperglycemia, including the cellular responses to high glucose and the responses in vascular, glomerular, podocyte, and tubular function. The molecular basis, characteristics, and consequences of the unique growth phenotypes observed in the diabetic kidney, including glomerular structures and tubular segments, are outlined. We delineate mechanisms of early diabetic glomerular hyperfiltration including primary vascular events as well as the primary role of tubular growth, hyperreabsorption, and tubuloglomerular communication as part of a "tubulocentric" concept of early diabetic kidney function. The latter also explains the "salt paradox" of the early diabetic kidney, that is, a unique and inverse relationship between glomerular filtration rate and dietary salt intake. The mechanisms and consequences of the intrarenal activation of the renin-angiotensin system and of diabetes-induced tubular glycogen accumulation are discussed. Moreover, we aim to link the changes that occur early in the diabetic kidney including the growth phenotype, oxidative stress, hypoxia, and formation of advanced glycation end products to mechanisms involved in progressive kidney disease.
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Affiliation(s)
- Volker Vallon
- Department of Medicine, University of California San Diego & VA San Diego Healthcare System, San Diego, California, USA.
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11
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Kong J, Zhu X, Shi Y, Liu T, Chen Y, Bhan I, Zhao Q, Thadhani R, Li YC. VDR attenuates acute lung injury by blocking Ang-2-Tie-2 pathway and renin-angiotensin system. Mol Endocrinol 2013; 27:2116-25. [PMID: 24196349 DOI: 10.1210/me.2013-1146] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Acute lung injury (ALI) is a hallmark of systemic inflammation associated with high mortality. Although the vitamin D receptor (VDR) is highly expressed in the lung, its role in lung physiology remains unclear. We investigated the effect of VDR deletion on ALI using a lipopolysaccharide (LPS)-induced sepsis model. After LPS challenge VDR-null mice exhibited more severe ALI and higher mortality compared with wild-type (WT) counterparts, manifested by increased pulmonary vascular leakiness, pulmonary edema, apoptosis, neutrophil infiltration, and pulmonary inflammation, which was accompanied by excessive induction of angiopoietin (Ang)-2 and myosin light chain (MLC) phosphorylation in the lung. 1,25-Dihydroxyvitamin D blocked LPS-induced Ang-2 expression by blocking nuclear factor-κB activation in human pulmonary artery endothelial cells. The severity of lung injury seen in VDR-null mice was ameliorated by pretreatment with L1-10, an antagonist of Ang-2, suggesting that VDR signaling protects the pulmonary vascular barrier by targeting the Ang-2-Tie-2-MLC kinase cascade. Severe ALI in VDR-null mice was also accompanied by an increase in pulmonary renin and angiotensin II levels, and pretreatment of VDR-null mice with angiotensin II type 1 receptor blocker losartan partially ameliorated the severity of LPS-induced lung injury. Taken together, these observations provide evidence that the vitamin D-VDR signaling prevents lung injury by blocking the Ang-2-Tie-2-MLC kinase cascade and the renin-angiotensin system.
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Affiliation(s)
- Juan Kong
- Laboratory of Metabolic Disease Research and Drug Development and Shengjing Hospital, China Medical University, Shenyang, 110000, China; ; Ravi Thadhani, M.P.H., Renal Unit, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114. E-mail: ; and Yan Chun Li, Department of Medicine, The University of Chicago, 900 East 57th Street, KCBD 9110, Chicago, Illinois 60637. E-mail:
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12
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Wang Y, Deb DK, Zhang Z, Sun T, Liu W, Yoon D, Kong J, Chen Y, Chang A, Li YC. Vitamin D receptor signaling in podocytes protects against diabetic nephropathy. J Am Soc Nephrol 2012; 23:1977-86. [PMID: 23123403 DOI: 10.1681/asn.2012040383] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Vitamin D and its analogs have antiproteinuric activity and podocytes express the vitamin D receptor, but whether vitamin D signaling in podocytes accounts for this renoprotection is unknown. To investigate this question, we used the 2.5 kb podocin promoter to target Flag-tagged human vitamin D receptor (hVDR) to podocytes in DBA/2J mice. After the induction of diabetes with streptozotocin, transgenic mice had less albuminuria than wild-type controls. In transgenic mice, a low dose of the vitamin D analog doxercalciferol prevented albuminuria, markedly attenuated podocyte loss and apoptosis, and reduced glomerular fibrosis, but it had little effect on the progression of diabetic nephropathy in wild-type mice. Moreover, reconstitution of VDR-null mice with the hVDR transgene in podocytes rescued VDR-null mice from severe diabetes-related renal damage. In culture, 1,25-dihydroxyvitamin D suppressed high-glucose-induced apoptosis of podocytes by blocking p38- and ERK-mediated proapoptotic pathways. Taken together, these data provide strong evidence that vitamin D/VDR signaling in podocytes plays a critical role in the protection of the kidney from diabetic injury.
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Affiliation(s)
- Youli Wang
- Department of Medicine, Division of Biological Sciences, The University of Chicago, Chicago, IL 60637, USA
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13
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Chen C, Du J, Feng W, Song Y, Lu Z, Xu M, Li Z, Zhang Y. β-Adrenergic receptors stimulate interleukin-6 production through Epac-dependent activation of PKCδ/p38 MAPK signalling in neonatal mouse cardiac fibroblasts. Br J Pharmacol 2012; 166:676-88. [PMID: 22103274 DOI: 10.1111/j.1476-5381.2011.01785.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE IL-6 plays crucial roles in cardiac hypertrophy, cardiac fibrosis and heart failure. Activation of β-adrenoceptors induced IL-6 production in neonatal mouse cardiac fibroblasts (NMCFs) through a G(s) /adenylate cyclase/cAMP/p38 MAPK pathway but independent of PKA. However, how cAMP activates p38 MAPK is still not defined. In this study, we have assessed the role of the exchange protein directly activated by cAMP (Epac) and PKCδ in p38 MAPK activation and IL-6 production by stimulated by the β-adrenoceptor agonist isoprenaline in NMCFs. EXPERIMENTAL APPROACH The IL-6 concentration in cell culture supernatants was measured by ELISA. The levels of phosphorylated and total p38 MAPK and PKCδ were determined by Western blot analysis. The translocation of PKCδ was determined by immunoblotting the soluble and particulate fractions. Expression of Epac1 or PKCδ was knocked down by the corresponding, adenovirus-mediated, small hairpin RNA (shRNA). RESULTS In NMCFs, activation of β-adrenoceptors enhanced PKCδ phosphorylation and translocation. Furthermore, knock-down of the PKCδ isoform using an adenovirus-mediated shRNA markedly down-regulated IL-6 induction by NMCFs stimulated with isoprenaline. Moreover, knock-down of Epac1 confirmed that Epac1 was upstream of PKCδ in IL-6 production. Additionally, both Epac1 and PKCδ mediated the p38 MAPK activation induced by isoprenaline. CONCLUSIONS AND IMPLICATIONS β-Adrenoceptor agonists activate a cAMP/Epac/PKCδ/p38 MAPK pathway to produce IL-6 in NMCFs. This study identifies Epac as the link between cAMP and p38 MAPK signalling pathways and demonstrates that PKCδ can function as a novel downstream effector of this β-adrenoceptor/cAMP/Epac pathway.
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Affiliation(s)
- Chao Chen
- Institute of Vascular Medicine, Peking University Third Hospital, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health and Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China
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Involvement of the intrarenal renin-angiotensin system in experimental models of glomerulonephritis. J Biomed Biotechnol 2012; 2012:601786. [PMID: 22811597 PMCID: PMC3395438 DOI: 10.1155/2012/601786] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Accepted: 06/09/2012] [Indexed: 01/13/2023] Open
Abstract
The intrarenal renin-angiotensin system (RAS) has several pathophysiologic functions not only in blood pressure regulation but also in the development of glomerulonephritis (GN). Angiotensin II (Ang II) is the biologically active product of the RAS. Locally produced Ang II induces inflammation, renal cell growth, mitogenesis, apoptosis, migration, and differentiation, regulates the gene expression of bioactive substances, and activates multiple intracellular signaling pathways, leading to tissue damage. Activation of the Ang II type 1 (AT1) receptor pathway results in the production of proinflammatory mediators, cell proliferation, and extracellular matrix synthesis, which facilitates glomerular injury. Previous studies have shown that angiotensin-converting enzyme inhibitors and/or AT1 receptor blockers have beneficial effects in experimental GN models and humans with various types of GN, and that these effects are more significant than their suppressive effects on blood pressure. In this paper, we focus on intrarenal RAS activation in the pathophysiology of experimental models of GN.
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Li L, Li W, Ren Z, He S, Xu G, Yang L. Effect of heparin-derived oligosaccharide on vascular smooth muscle cell proliferation. Vasc Endovascular Surg 2012; 46:393-400. [PMID: 22604860 DOI: 10.1177/1538574412442595] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In this study, the effect of heparin-derived oligosaccharide on bovine vascular smooth muscle cell (VSMC) proliferation and signal transduction mechanism was investigated. Extracellular-signal-regulated kinase (ERK) 1/2 has been implicated in the regulation of various cellular functions including proliferation, and we sought to define a functional role for ERK 1/2 in an established proliferation model in order to find a possible mechanism for inhibition of VSMC proliferation by heparin-derived oligosaccharide. The VSMC proliferation model was developed by platelet-derived growth factor (PDGF), and the level of ERK 1/2 protein and messenger RNA was determined by reverse transcriptase-polymerase chain reaction, Western blotting, and immunocytochemical methods. Flow cytometry analysis indicated that heparin-derived oligosaccharide blocked PDGF-induced cell cycle progression by arresting cells in the G0/G1 phase. The results imply that heparin-derived oligosaccharide inhibits VSMC proliferation by moderating the gene and the phosphorylation levels of ERK 1/2, eventually blocking G1/S transition, may be one of the mechanisms for inhibition of VSMC proliferation by heparin-derived oligosaccharide.
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Affiliation(s)
- Li Li
- School of Life Science and Technology, China Pharmaceutical University, Nanjing, China
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16
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Lakshmanan AP, Thandavarayan RA, Watanabe K, Sari FR, Meilei H, Giridharan VV, Sukumaran V, Soetikno V, Arumugam S, Suzuki K, Kodama M. Modulation of AT-1R/MAPK cascade by an olmesartan treatment attenuates diabetic nephropathy in streptozotocin-induced diabetic mice. Mol Cell Endocrinol 2012; 348:104-11. [PMID: 21827824 DOI: 10.1016/j.mce.2011.07.041] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Revised: 07/20/2011] [Accepted: 07/22/2011] [Indexed: 10/17/2022]
Abstract
There is increasing evidence that angiotensin (Ang)-II plays an unprecedented role in diabetic complications. It could also be an important therapeutic target for ameliorating various diseases, especially diabetic nephropathy (DN). We therefore studied the beneficial effects of olmesartan, an Ang-II type 1 receptor (AT-1R) blocker in streptozotocin (150 mg/kg, BW)-induced diabetic kidney disease in mice. The diabetic kidney mice displayed upregulated protein expression levels of AT-1R, AT-2R, ERK-1/2, p-p38 MAPK, p-MAPKAPK-2, ET-1, p-JNK, p-c-Jun, TGF-β1, and gp91-phox, and all of these effects were expectedly downregulated by an olmesartan treatment. Also, immunohistochemical analysis, and Azan-Mallory and HE staining were performed to examine the expression of collagen-III and fibronectin, renal fibrosis, and hypertrophy, respectively. Furthermore, olmesartan treatment significantly abrogated the downregulation of ACE-2 and Ang-(1-7) mas R protein expression in diabetic kidney mice. Considering all these findings together, the AT-1R/MAPK pathway might be a potential therapeutic target in diabetes kidney disease, and olmesartan treatment could have beneficial effects on DN by modulating the AT-1R/MAPK pathway.
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Affiliation(s)
- Arun Prasath Lakshmanan
- Department of Clinical Pharmacology, Faculty of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata City 956-8603, Japan
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17
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Goldberg H, Whiteside C, Fantus IG. O-linked β-N-acetylglucosamine supports p38 MAPK activation by high glucose in glomerular mesangial cells. Am J Physiol Endocrinol Metab 2011; 301:E713-26. [PMID: 21712532 DOI: 10.1152/ajpendo.00108.2011] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Hyperglycemia augments flux through the hexosamine biosynthetic pathway and subsequent O-linkage of single β-N-acetyl-d-glucosamine moieties to serine and threonine residues on cytoplasmic and nuclear proteins (O-GlcNAcylation). Perturbations in this posttranslational modification have been proposed to promote glomerular matrix accumulation in diabetic nephropathy, but clear evidence and mechanism are lacking. We tested the hypothesis that O-GlcNAcylation enhances profibrotic signaling in rat mesangial cells. An adenovirus expressing shRNA directed against O-GlcNAc transferase (OGT) markedly reduced basal and high-glucose-stimulated O-GlcNAcylation. Interestingly, O-GlcNAc depletion prevented high-glucose-induced p38 mitogen-activated protein kinase (MAPK) and c-Jun NH(2)-terminal kinase phosphorylation. Downstream of p38, O-GlcNAc controlled the expression of plasminogen activator inhibitor-1, fibronectin, and transforming growth factor-β, important factors in matrix accumulation in diabetic nephropathy. Treating mesangial cells with thiamet-G, a highly selective inhibitor of O-GlcNAc-specific hexosaminidase (O-GlcNAcase), increased O-GlcNAcylation and p38 phosphorylation. The high-glucose-stimulated kinase activity of apoptosis signal-regulating kinase 1 (ASK1), an upstream MAPK kinase kinase for p38 that is negatively regulated by Akt, was inhibited by OGT shRNA. Akt Thr(308) and Ser(473) phosphorylation were enhanced following OGT shRNA expression in high-glucose-exposed mesangial cells, but high-glucose-induced p38 phosphorylation was not attenuated by OGT shRNA in cells pretreated with the phosphatidylinositol 3-kinase inhibitor LY-294002. OGT shRNA also reduced high-glucose-stimulated reactive oxygen species (ROS) formation. In contrast, diminished O-GlcNAcylation caused elevated ERK phosphorylation and PKCδ membrane translocation. Thus, O-GlcNAcylation is coupled to profibrotic p38 MAPK signaling by high glucose in part through Akt and possibly through ROS.
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Affiliation(s)
- Howard Goldberg
- Department of Medicine, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
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18
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Zhang Z, Luo X, Ding S, Chen J, Chen T, Chen X, Zha H, Yao L, He X, Peng H. MicroRNA-451 regulates p38 MAPK signaling by targeting of Ywhaz and suppresses the mesangial hypertrophy in early diabetic nephropathy. FEBS Lett 2011; 586:20-6. [PMID: 21827757 DOI: 10.1016/j.febslet.2011.07.042] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 07/27/2011] [Accepted: 07/27/2011] [Indexed: 12/27/2022]
Abstract
Diabetic nephropathy (DN) is a major diabetic complication. However, the initiating molecular events triggering DN are unknown. In this study we focused on microRNA-451 (miR-451), which is downregulated during early DN. We found that miR-451 negatively regulated the expression of Ywhaz through Ywhaz 3'UTR and that Ywhaz was required for the miR-451-mediated downregulation of p38 MAPK signalling. Moreover, over-expression of miR-451 inhibits glomerular mesangial cell proliferation in vitro and in vivo. These findings suggest that the growth-inhibitory effect of miR-451 may be explained in part by miR-451-induced suppression of Ywhaz and p38 MAPK signalling, providing evidence for the potential role of miR-451 in early DN.
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Affiliation(s)
- Zheng Zhang
- Department of Cell Biology and Medical Genetics, Chongqing Medical University, No. 1, Medical College Road, Chongqing, China.
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Fang S, Jin Y, Zheng H, Yan J, Cui Y, Bi H, Jia H, Zhang H, Wang Y, Na L, Gao X, Zhou H. High glucose condition upregulated Txnip expression level in rat mesangial cells through ROS/MEK/MAPK pathway. Mol Cell Biochem 2010; 347:175-82. [PMID: 20953987 DOI: 10.1007/s11010-010-0626-z] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2010] [Accepted: 10/07/2010] [Indexed: 11/26/2022]
Abstract
Thioredoxin interacting protein (Txnip) is one of the most abundantly up-regulated genes in response to hyperglycemia. The increased renal expression of Txnip was associated with type IV collagen accumulation in streptozotocin-induced diabetic mice. As the mechanism of action of high glucose is unknown, we undertook the investigation of the signaling pathway on the upregulation of Txnip expression induced by high glucose in rat mesangial cells. Rat mesangial cells were exposed to normal (5.5 mM) or high (25 mM) glucose at different time points. Txnip expression was determined using real-time RT-PCR and western-blotting at transcription and translation level, respectively. Intracellular reactive oxygen species (ROS) was detected by FACS Calibur flow cytometer using fluorescent probe (DCFH-DA).The treatment with high glucose resulted in an increase of Txnip mRNA from 4 h to 12 h and Txnip protein from 12 to 24 h in comparison with normal glucose condition. In addition, N-acetyl-cysteine (NAC) was found to decrease Txnip protein expression under high glucose condition. Furthermore, p38MAPK inhibitor SB203580 suppressed Txnip expression at transcription and protein level significantly to high glucose exposure. These results suggest that high glucose exposure improves Txnip mRNA and protein expression level by ROS/MEK/MAPK signaling pathway.
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Affiliation(s)
- Shaohong Fang
- Department of Biochemistry and Molecular Biology, Harbin Medical University, Harbin, 150081, People's Republic of China
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20
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Liu Y, Jia L, Liu ZC, Zhang H, Zhang PJ, Wan Q, Wang R. Emodin ameliorates high-glucose induced mesangial p38 over-activation and hypocontractility via activation of PPARgamma. Exp Mol Med 2010; 41:648-55. [PMID: 19478555 DOI: 10.3858/emm.2009.41.9.071] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Early stage diabetic nephropathy is characterized by elevated glomerular filtration. Recent studies have identified high-glucose induced p38 MAPK (p38) over-activation in mesangial cells. Mesangial hypocontractility is the major underlying mechanism, however, no ameliorating agents are currently available. We investigated the protective effects of emodin on high-glucose induced mesangial cell hypocontractility. Mesangial cells were cultured under normal (5.6 mM) and high glucose (30 mM) conditions. Emodin was administrated at doses of 50 mg/l and 100 mg/l. Angiotension II stimulated cell surface reductions were measured to evaluate cell contractility. p38 activity was detected using Western blotting. To further explore the possible mechanism of emodin, expression of the peroxisome proliferator- activated receptorgamma (PPARgamma) was measured and its specific inhibitor, gw9662, was administrated. Our results showed: (1) high-glucose resulted in a 280% increase in p38 activity associated with significant impairment of mesangial contractility; (2) emodin treatment dose-dependently inhibited high-glucose induced p38 over-activation (a 40% decrease for 50 mg/l emodin and a 73% decrease for 100 mg/l emodin), and mesangial hypocontractility was ameriolated by emodin; (3) both the PPARgamma mRNA and protein levels were elevated after emodin treatment; (4) inhibition of PPARgamma using gw9662 effectively blocked the ameliorating effects of emodin on high-glucose induced p38 over-activation and mesangial hypocontractility. Emodin effectively ameliorated p38 over-activation and hypocontractility in high-glucose induced mesangial cells, possibly via activation of PPARgamma.
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Affiliation(s)
- Yi Liu
- Department of Nephrology, Shandong Provincial Hospital, Shandong University, Shandong 250021, China
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21
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Gaddini L, Villa M, Matteucci A, Mallozzi C, Petrucci TC, Di Stasi AMM, Leo L, Malchiodi-Albedi F, Pricci F. Early effects of high glucose in retinal tissue cultures Renin-Angiotensin system-dependent and -independent signaling. Neurobiol Dis 2009; 35:278-85. [PMID: 19481149 DOI: 10.1016/j.nbd.2009.05.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2009] [Revised: 04/27/2009] [Accepted: 05/15/2009] [Indexed: 12/14/2022] Open
Abstract
The early effects of the diabetic milieu on retinal tissue and their relation to the Renin-Angiotensin system (RAS) activation are poorly known. Here we investigated RAS signaling in retinas explanted from adult rats exposed for 48 h to high glucose (HG), with or without the Angiotensin Converting Enzyme inhibitor enalaprilat, which blocks RAS. HG was observed to i) initiate a phosphotyrosine-dependent signaling cascade; ii) up-regulate Angiotensin(1) Receptor (AT(1)R); iii) activate src tyrosine kinase and increase phosphorylation of Pyk2, PLCgamma1 and ERK1/2; and iv) activate Akt and the transcription factor CREB. In the presence of enalaprilat, tyrosine phosphorylation signal and AT(1)R upregulation decreased and activation of PLCgamma1 and CREB reverted, showing their relation to RAS signaling. In line with Akt activation, no apoptosis or synapse degeneration was found. Müller glia was activated, but in a RAS-independent manner. Our results suggest that, in early phases of HG exposure, a pro-survival cell program may be induced in the retina.
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Affiliation(s)
- Lucia Gaddini
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome 00161, Italy
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22
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Naito M, Shenoy A, Aoyama I, Koopmeiners JS, Komers R, Schnaper HW, Bomsztyk K. High ambient glucose augments angiotensin II-induced proinflammatory gene mRNA expression in human mesangial cells: effects of valsartan and simvastatin. Am J Nephrol 2009; 30:99-111. [PMID: 19225232 DOI: 10.1159/000203619] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Accepted: 01/16/2009] [Indexed: 12/28/2022]
Abstract
BACKGROUND Hyperglycemia may potentiate the adverse renal effects of angiotensin II (AII). In the kidney, the major target of AII action is the glomerular mesangial cell, where its hemodynamic and proinflammatory action contributes to renal injury. AII action is mediated by several types of cell receptors. Among those, the AT1 receptor has been best studied using specific AII receptor blockers (ARBs). These agents have emerged as major new modalities in the prevention and amelioration of renal disease where the ARB renoprotective anti-inflammatory properties could be more important than previously appreciated. Like the ARBs, statins may also modulate inflammatory responses that are renoprotective and complement their cholesterol-lowering effects. AIM The aim of this project was to (i) identify a repertoire of proinflammatory mesangial cell AII-inducible mRNAs; (ii) determine if the AII-induced proinflammatory mRNA responses depend on ambient glucose, and (iii) test the anti-inflammatory effectiveness of an ARB, valsartan, either alone or in combination with a statin, simvastatin. RESULTS/CONCLUSIONS Using high-density microarrays and real-time PCR we identified several AII-inducible proinflammatory mesangial genes that exhibited augmented mRNA responses in high-glucose milieu. Valsartan blocked the AII-induced mRNA expression of proinflammatory genes (i.e. MCP-1, LIF and COX-2) maintained in normal and high glucose. These observations add to the mounting evidence that ARBs have anti-inflammatory effects in the kidney, a beneficial effect that may be more important in protecting renal function in diabetic patients. While simvastatin inhibited expression of some mRNAs encoding chemokines/cytokines, it enhanced expression of mRNA encoding COX-2, a key mediator of inflammation. Thus, the non-cholesterol effects of statins on inflammatory responses appear complex.
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Affiliation(s)
- Masayo Naito
- UW Medicine Lake Union Research, University of Washington, Seattle, WA 98109, USA
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Chandak PG, Gaikwad AB, Tikoo K. Gallotannin ameliorates the development of streptozotocin-induced diabetic nephropathy by preventing the activation of PARP. Phytother Res 2009; 23:72-7. [PMID: 18693296 DOI: 10.1002/ptr.2559] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Poly(ADP-ribose) polymerase (PARP) is known to be activated under conditions of oxidative stress and/or radiation exposure. The role of this enzyme has been well demonstrated in the streptozotocin (STZ) induced model of diabetes. Inhibition of PARP by specific inhibitors is known to prevent the development of STZ induced diabetic nephropathy by reduction in oxidative stress induced apoptosis. This study shows for the first time the role of poly(ADP-ribose) glycohydrolase (PARG) inhibitors as an alternative approach for inhibition of PARP. Gallotannin (20 mg/kg/day, i.p.) treatment for 4 weeks led to a significant reduction in the levels of plasma creatinine which is a well known marker for diabetic nephropathy. Treatment with gallotannin resulted in protection up to a certain level of glomerular damage, suggesting compensatory glomerular hypertrophy. As a PARG inhibitor gallotannin treatment also showed protection in PARP cleavage which is a hallmark for apoptotic cell death signifying the protective role of gallotannin in cell death signaling.
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Affiliation(s)
- Prakash Gopaldas Chandak
- Laboratory of Chromatin Biology, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S. Nagar (Mohali) - 160 062, Punjab, India
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Effects of p38 mitogen-activated protein kinase inhibition on blood pressure, renal hemodynamics, and renal vascular reactivity in normal and diabetic rats. Transl Res 2007; 150:343-9. [PMID: 18022596 DOI: 10.1016/j.trsl.2007.07.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2007] [Revised: 07/10/2007] [Accepted: 07/12/2007] [Indexed: 11/23/2022]
Abstract
p38 mitogen-activated protein kinase (p38) has been implicated in mediating vascular smooth muscle and mesangial cell contraction in response to several vasoactive factors, including angiotensin II. Early stages of diabetic nephropathy are associated with renal hemodynamic changes that are, at least in part, attributable to the dysbalance of vasoactive factors that control afferent and efferent arteriolar tone resulting in increased glomerular capillary pressure. Vascular and renal p38 have been found to be activated in diabetes. Therefore, p38 may be involved in the control of systemic and renal hemodynamics in diabetes. To address this issue, mean arterial blood pressure (MAP), glomerular filtration rate (GFR, inulin clearance), renal plasma flow (RPF, PAH clearance), metabolic parameters, and plasma renin concentrations (PRC) were determined in streptozotocin-diabetic rats (DM), and in age-matched non-diabetic controls (C), administered with the p38 inhibitor SB 239063 (SB, 50 mg/bwt, p.o.) or with vehicle. Furthermore, renal vascular responses to p38 inhibition (SB 202190, 25 microM) before and after stimulation with the endothelium-dependent vasodilator acetylcholine (ACh) were studied in vitro in tertiary branches of the renal artery from separate groups of DM and C rats, using a fixed support and a force transducer in a myograph system. SB treatment was associated with marked reductions in MAP and GFR in both C and DM rats, whereas RPF remained unchanged, as compared with vehicle-treated animals. Observed differences in MAP and renal hemodynamics were not associated with changes in urinary sodium excretion or PRC. Incubation of KCl-contracted renal arteries from both C and DM rats with the p38 inhibitor resulted in progressive and significant vasorelaxation. Also, vessels from control and diabetic rats treated with the p38 inhibitor exhibited enhancement of ACh-induced vasorelaxation. These data indicate the role of p38 in the control of systemic and renal hemodynamics both in normal and in diabetic rats. The observed effects of p38 inhibition could be mediated at least in part by enhancement of endothelium-dependent vasodilation.
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Wang T, Shankar K, Ronis MJ, Mehendale HM. Mechanisms and outcomes of drug- and toxicant-induced liver toxicity in diabetes. Crit Rev Toxicol 2007; 37:413-59. [PMID: 17612954 DOI: 10.1080/10408440701215100] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Increase dincidences of hepatotoxicity have been observed in diabetic patients receiving drug therapies. Neither the mechanisms nor the predisposing factors underlying hepatotoxicity in diabetics are clearly understood. Animal studies designed to examine the mechanisms of diabetes-modulated hepatotoxicity have traditionally focused only on bioactivation/detoxification of drugs and toxicants. It is becoming clear that once injury is initiated, additional events determine the final outcome of liver injury. Foremost among them are two leading mechanisms: first, biochemical mechanisms that lead to progression or regression of injury; and second, whether or not timely and adequate liver tissue repair occurs to mitigate injury and restore liver function. The liver has a remarkable ability to repair and restore its structure and function after physical or chemical-induced damage. The dynamic interaction between biotransformation-based liver injury and compensatory tissue repair plays a pivotal role in determining the ultimate outcome of hepatotoxicity initiated by drugs or toxicants. In this review, mechanisms underlying altered hepatotoxicity in diabetes with emphasis on both altered bioactivation and liver tissue repair are discussed. Animal models of both marked sensitivity (diabetic rats) and equally marked protection (diabetic mice) from drug-induced hepatotoxicity are described. These examples represent a remarkable species difference. Availability of the rodent diabetic models offers a unique opportunity to uncover mechanisms of clinical interest in averting human diabetic sensitivity to drug-induced hepatotoxicities. While the rat diabetic models appear to be suitable, the diabetic mouse models might not be suitable in preclinical testing for potential hepatotoxic effects of drugs or toxicants, because regardless of type 1 or type2 diabetes, mice are resistant to acute drug-or toxicant-induced toxicities.
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Affiliation(s)
- T Wang
- Department of Toxicology, College of Pharmacy, University of Louisiana at Monroe, Monroe, Louisiana 71209, USA
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Sawant SP, Dnyanmote AV, Mehendale HM. Mechanisms of inhibited liver tissue repair in toxicant challenged type 2 diabetic rats. Toxicology 2007; 232:200-15. [PMID: 17298859 DOI: 10.1016/j.tox.2007.01.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2006] [Revised: 01/01/2007] [Accepted: 01/05/2007] [Indexed: 01/08/2023]
Abstract
Liver injury initiated by non-lethal doses of CCl(4) and thioacetamide (TA) progresses to hepatic failure and death of type 2 diabetic (DB) rats due to failed advance of liver cells from G(0)/G(1) to S-phase and inhibited tissue repair. Objective of the present study was to investigate cellular signaling mechanisms of failed cell division in DB rats upon hepatotoxicant challenge. In CCl(4)-treated non-diabetic (non-DB) rats, increased IL-6 levels, sustained activation of extracellular regulated kinases 1/2 (ERK1/2) MAPK, and sustained phosphorylation of retinoblastoma protein (p-pRB) via cyclin D1/cyclin-dependent kinase (cdk) 4 and cyclin D1/cdk6 complexes stimulated G(0)/G(1) to S-phase transition of liver cells. In contrast to the non-DB rats, CCl(4) administration led to lower plasma IL-6, decreased ERK1/2 activation, lower cyclin D1, and cdk 4/6 expression resulting in decreased p-pRB and inhibition of liver cell division in the DB rats. Furthermore, higher TGFbeta1 expression and p21 activation may also contribute to decreased p-pRB in DB rats compared to non-DB rats. Similarly, after TA administration to DB rats, down-regulation of cyclin D1 and p-pRB leads to markedly decreased advance of liver cells from G(0)/G(1) to S-phase and tissue repair compared to the non-DB rats. Hepatic ATP levels did not differ between the DB and non-DB rats obviating its role in failed tissue repair in the DB rats. In conclusion, decreased p-pRB may contribute to blocked advance of cells from G(0)/G(1) to S-phase and failed cell division in DB rats exposed to CCl(4) or TA, leading to progression of liver injury and hepatic failure.
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Affiliation(s)
- Sharmilee P Sawant
- Department of Toxicology, College of Pharmacy, The University of Louisiana at Monroe, 700 University Avenue, Sugar Hall #306, Monroe, LA 71209-0470, USA
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27
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Li XC, Carretero OA, Zhuo JL. Cross-talk between angiotensin II and glucagon receptor signaling mediates phosphorylation of mitogen-activated protein kinases ERK 1/2 in rat glomerular mesangial cells. Biochem Pharmacol 2006; 71:1711-9. [PMID: 16643859 PMCID: PMC2276839 DOI: 10.1016/j.bcp.2006.03.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2006] [Revised: 03/16/2006] [Accepted: 03/16/2006] [Indexed: 12/26/2022]
Abstract
We have recently shown that the pancreatic hormone glucagon-induced phosphorylation of mitogen-activated protein (MAP) kinase ERK 1/2 as well as growth and proliferation of rat glomerular mesangial cells (MCs) via activation of cAMP-dependent protein kinase A (PKA)- and phospholipase C (PLC)/Ca2+-mediated signaling pathways. Since circulating glucagon and tissue angiotensin II (Ang II) levels are inappropriately elevated in type 2 diabetes, we tested the hypothesis that glucagon induces phosphorylation of ERK 1/2 in MCs by interacting with Ang II receptor signaling. Stimulation of MCs by glucagon (10 nM) induced a marked increase in intracellular [Ca2+]i that was abolished by [Des-His1, Glu9]-glucagon (1 microM), a selective glucagon receptor antagonist. Both glucagon and Ang II-induced ERK 1/2 phosphorylation (glucagon: 214+/-14%; Ang II: 174+/-16%; p<0.001 versus control), and these responses were inhibited by the AT1 receptor blocker losartan (glucagon + losartan: 77+/-14%; Ang II + losartan: 84+/-18%; p<0.01 versus glucagon or Ang II) and the AT2 receptor blocker PD 123319 (glucagon + PD: 78+/-7%; Ang II + PD: 87+/-7%; p<0.01 versus glucagon or Ang II). Inhibition of cAMP-dependent PKA with H89 (1 microM) or PLC with U73122 (1 microM) also markedly attenuated the phosphorylation of ERK 1/2 induced by glucagon (glucagon + U73122: 109+/-15%; glucagon + H89: 113+/-16%; p<0.01 versus glucagon) or Ang II (Ang II + U73122: 111+/-13%; Ang II + H89: 86+/-10%; p<0.01 versus Ang II). Wortmannin (1 microM), a selective PI 3-kinase inhibitor, also blocked glucagon- or Ang II-induced ERK 1/2 phosphorylation. These results suggest that AT1 receptor-activated cAMP-dependent PKA, PLC and PI 3-kinase signaling is involved in glucagon-induced MAP kinase ERK 1/2 phosphorylation in MCs. The inhibitory effect of PD 123319 on glucagon-induced ERK 1/2 phosphorylation further suggests that AT2 receptors also play a similar role in this response.
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Affiliation(s)
- Xiao C. Li
- Laboratory of Receptor and Signal Transduction, Division of Hypertension and Vascular Research, Henry Ford Hospital, Detroit, MI 48202, USA
| | - Oscar A. Carretero
- Laboratory of Receptor and Signal Transduction, Division of Hypertension and Vascular Research, Henry Ford Hospital, Detroit, MI 48202, USA
| | - Jia L. Zhuo
- Laboratory of Receptor and Signal Transduction, Division of Hypertension and Vascular Research, Henry Ford Hospital, Detroit, MI 48202, USA
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA
- * Corresponding author at: Laboratory of Receptor and Signal Transduction, Division of Hypertension and Vascular Research, Henry Ford Hospital, 2799 West Grand Blvd., Detroit, MI 48202, USA. Tel.: +1 313 916 4958; fax: +1 313 916 1479. E-mail address: (J.L. Zhuo)
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Li XC, Carretero OA, Shao Y, Zhuo JL. Glucagon receptor-mediated extracellular signal-regulated kinase 1/2 phosphorylation in rat mesangial cells: role of protein kinase A and phospholipase C. Hypertension 2006; 47:580-5. [PMID: 16391176 PMCID: PMC2367309 DOI: 10.1161/01.hyp.0000197946.81754.0a] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Glucagon, a major insulin counterregulatory hormone, binds to specific Gs protein-coupled receptors to activate glycogenolytic and gluconeogenic pathways, causing blood glucose levels to increase. Inappropriate increases in serum glucagon play a critical role in the development of insulin resistance and target organ damage in type 2 diabetes. We tested the hypotheses that: (1) glucagon induces proliferation of rat glomerular mesangial cells through glucagon receptor-activated phosphorylation of mitogen-activated protein kinase extracellular signal-regulated kinase 1/2 (p-ERK 1/2); and (2) this phosphorylation involves activation of cAMP-dependent protein kinase A (PKA) and phospholipase C (PLC)/[Ca2+]i signaling pathways. In rat mesangial cells, glucagon (1 nM) stimulated [3H]-thymidine incorporation by 96% (P<0.01). This proliferative effect was blocked by the specific glucagon receptor antagonist [Des-His1-Glu9] glucagon (1 micromol/L; P<0.01), a mitogen-activated protein kinase/ERK kinase inhibitor PD98059 (10 micromol/L; P<0.01), a PLC inhibitor U73122 (1 micromol/L; P<0.01), or a PKA inhibitor H-89 (1 micromol/L; P<0.01). The proliferation was associated with a 2-fold increase in p-ERK 1/2 that peaked 5 minutes after glucagon stimulation (P<0.01) and also was blocked by [Des-His1-Glu9] glucagon. Total ERK 1/2 was not affected by glucagon. Pretreating of mesangial cells with U73122 or H89 significantly attenuated ERK 1/2 phosphorylation induced by glucagon. We believe that these are the first data showing that glucagon activates specific receptors to induce ERK 1/2 phosphorylation and thereby increase mesangial cell proliferation and that this effect of glucagon involves both PLC/[Ca2+]i- and cAMP-dependent PKA-activated signaling cascades.
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Affiliation(s)
- Xiao C Li
- Division of Hypertension and Vascular Research, Henry Ford Hospital, Detroit, MI 48202, USA
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Kwan J, Wang H, Munk S, Xia L, Goldberg HJ, Whiteside CI. In high glucose protein kinase C-zeta activation is required for mesangial cell generation of reactive oxygen species. Kidney Int 2006; 68:2526-41. [PMID: 16316329 DOI: 10.1111/j.1523-1755.2005.00660.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND We postulated that in mesangial cells exposed to high glucose, protein kinase C-zeta (PKC-zeta) is necessary for the generation of reactive oxygen species (ROS) by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and that the requirement of PKC-zeta for filamentous (F)-actin disassembly may involve ROS. To identify signaling mechanisms relevant to PKC-zeta activation and ROS generation, including phosphoinositide 3 kinase (PI3 kinase), we examined mesangial cell stimulation with platelet-derived growth factor (PDGF). METHODS In primary rat mesangial cells cultured in 5.6 mmol/L or 30 mmol/L d-glucose, PKC-zeta expression was identified with immunoblotting and activity was analyzed in cell membrane immunoprecipitates and by confocal immunofluorescence imaging. ROS generation was measured by dichlorofluorescein fluorescence using confocal microscopy and was inhibited by transfection of antisense against NADPH subunits p22(phox) or p47(phox) or with Tempol. F-actin disassembly was observed by dual-channel confocal fluorescence imaging. PI3 kinase activity was detected by immunoblotting of phosphorylated Akt. RESULTS In high glucose, generation of NADPH oxidase-dependent ROS was dependent on PKC-zeta. Conversely, sustained PKC-zeta activity was dependent on ROS generation, suggesting a positive feedback. PKC-zeta-dependent F-actin disassembly in high glucose required ROS generation. PDGF stimulated NADPH oxidase generation of ROS through a PKC-zeta mechanism that was independent of Akt phosphorylation and remained unchanged in high glucose. CONCLUSION In high glucose, mesangial cell PKC-zeta is required for ROS generation from NADPH oxidase similar to PDGF stimulation of PKC-zeta-dependent ROS generation through a pathway independent of PI3 kinase. F-actin disassembly in high glucose also requires ROS. A positive feedback loop occurs between ROS and the activation of PKC-zeta in high glucose.
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Affiliation(s)
- Janice Kwan
- Banting and Best Diabetes Centre, University of Toronto, Toronto, Canada
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Lee YJ, Park SH, Jeung TO, Kim KW, Lee JH, Han HJ. Effect of adenosine triphosphate on phosphate uptake in renal proximal tubule cells: involvement of PKC and p38 MAPK. J Cell Physiol 2005; 205:68-76. [PMID: 15880445 DOI: 10.1002/jcp.20367] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
ATP has been known to act as an extracellular signal and to be involved in various functions of kidney. Renal proximal tubular reabsorption of phosphate (Pi) contributes to the maintenance of phosphate homeostasis, which is regulated by Na+/Pi cotransporter. However, the effects of ATP on Na+/Pi cotransporters were not elucidated in proximal tubule cells (PTCs). Thus, the effects of ATP on Na+/Pi cotransporter and its related signal pathways are examined in the primary cultured renal PTCs. In the present study, ATP inhibited Pi uptake in a time (> 1 h) and dose (>10(-6)M) dependent manner. ATP-induced inhibition of Pi uptake was correlated with the decrease of type II Na+/Pi cotransporter mRNA. ATP-induced inhibition of Pi uptake may be mediated by P2Y receptor activation, since suramin (non-specific P2 receptor antagonist) and RB-2 (P2Y receptor antagonist) blocked it. ATP-induced inhibition of Pi uptake was blocked by neomycin, U73122 (phospholipase C (PLC) inhibitors), bisindolylmaleimide I, H-7, and staurosporine (protein kinase C (PKC) inhibitors), suggesting the role of PLC/PKC pathway. ATP also increased inositol phosphates (IPs) formation and induced PKC translocation from cytosolic fraction to membrane fraction. In addition, ATP-induced inhibition of Pi uptake was blocked by SB 203580 [a p38 mitogen activated protein kinase (MAPK) inhibitor], but not by PD 98059 (a p44/42 MAPK inhibitor). Indeed, ATP induced phosphorylation of p38 MAPK, which was not blocked by PKC inhibitor. In conclusion, ATP inhibited Pi uptake via PLC/PKC as well as p38 MAPK in renal PTCs.
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Affiliation(s)
- Yun Jung Lee
- Department of Veterinary Physiology, College of Veterinary Medicine, Chonnam National University, Gwangju, Korea
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Kobayashi T, Inoue T, Okada H, Kikuta T, Kanno Y, Nishida T, Takigawa M, Sugaya T, Suzuki H. Connective tissue growth factor mediates the profibrotic effects of transforming growth factor-beta produced by tubular epithelial cells in response to high glucose. Clin Exp Nephrol 2005; 9:114-21. [PMID: 15980944 DOI: 10.1007/s10157-005-0347-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2004] [Accepted: 03/02/2005] [Indexed: 01/04/2023]
Abstract
BACKGROUND It was reported that connective tissue growth factor (CTGF) was expressed in the tubular epithelial cells of the diabetic kidney. CTGF has, among other factors, been implicated in mediating the downstream, profibrotic effects of transforming growth factor-beta (TGF-beta), though is precise role in interstitial fibrogenesis in the diabetic kidney has not yet been clarified. METHODS We employed a coculture system involving cultured murine proximal tubular epithelial cells (mProx24) and renal fibroblasts (TFB), as a model of the subepithelial mesenchyme in the kidney in order to examine the profibrotic effects of CTGF derived from mProx24 cells in response to high glucose (30 mM). RESULTS We showed that glucose stimulated CTGF expression in cultured mProx24 in both a dose- and a time-dependent manner, and that this effect was mediated by increased levels of TGF-beta. We also found that high glucose significantly stimulated TFB cells to produce profibrotic molecules, such as type I collagen, the EIIIA isoform of fibronectin, and plasminogen activator inhibitor-1. The induction of these molecules was both direct and indirect, the latter induction being mediated by mProx24 cell-derived CTGF, which, in turn, was induced by TGF-beta that was produced by the mProx24 cells. CONCLUSIONS CTGF plays an important role in mediating renal interstitial fibrogenesis in response to high glucose and, as such, is a reasonable target for anti-fibrotic therapy.
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Affiliation(s)
- Tatsuya Kobayashi
- Department of Nephrology, Saitama Medical College, 38 Morohongo, Moroyama-machi, Saitama 350-0495, Japan
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Nishiyama A, Yoshizumi M, Rahman M, Kobori H, Seth DM, Miyatake A, Zhang GX, Yao L, Hitomi H, Shokoji T, Kiyomoto H, Kimura S, Tamaki T, Kohno M, Abe Y. Effects of AT1 receptor blockade on renal injury and mitogen-activated protein activity in Dahl salt-sensitive rats. Kidney Int 2004; 65:972-81. [PMID: 14871417 PMCID: PMC2573027 DOI: 10.1111/j.1523-1755.2004.00476.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND The mitogen-activated protein kinase (MAPK) cascade is an important intracellular mediator of angiotensin II (Ang II)-induced cell growth and differentiation. Here, we examined the effect of angiotensin II type 1 receptor (AT1) receptor blockade on renal injury and MAPK activity in Dahl salt-sensitive (DS) rats. METHODS DS rats were maintained on a high (H: 8.0%NaCl, N= 8) or low (L: 0.3%NaCl, N= 7) salt diet, or H + candesartan cilexetil (10 to 15 mg/kg/day, N= 8). Urinary protein excretion (UproteinV), renal cortical collagen content, and glomerular injury (assessed by semiquantitative morphometric analysis) were determined after 4-week treatments. Plasma and kidney Ang II levels were measured by radioimmunoassay. Protein levels of AT1 and AT2 receptors in the renal cortical tissues were analyzed by Western-blotting analyses. MAPKs activities, including extracellular signal-regulated kinases (ERK)1/2, c-Jun NH2-terminal kinases (JNK), p38 MAPK, and Big-MAPK-1 (BMK1), were measured by Western-blotting analyses or in vitro kinase assays. RESULTS DS/H rats showed higher mean blood pressure (MBP), UproteinV, and renal cortical collagen content than DS/L rats. Increased ERK1/2, JNK, and BMK1 activities were observed in renal cortical tissues of DS/H rats (approximately 6.3-, 4.5-, and 2.5-fold, respectively), whereas p38 MAPK activity was unchanged. Plasma Ang II levels were significantly reduced in DS/H rats compared with DS/L rats, whereas kidney Ang II contents and AT1 receptor protein levels were similar. Candesartan did not alter MBP, but significantly reduced UproteinV and collagen content, and ameliorated progressive sclerotic and proliferative glomerular changes. Furthermore, candesartan decreased renal tissue Ang II contents (from 216 +/- 19 to 46 +/- 3 fmol/mL) and ERK1/2, JNK, and BMK1 activities (-45%, -60%, and -70%, respectively) in DS/H rats. CONCLUSION In DS hypertensive rats, some of the renoprotective effects of AT1 receptor blockade are accompanied by reductions in intrarenal Ang II contents and MAPK activity, which might not be mediated through arterial pressure changes.
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Affiliation(s)
- Akira Nishiyama
- Department of Pharmacology, Research Equipment Center, Kagawa Medical University, Kagawa, Japan.
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Adhikary L, Chow F, Nikolic-Paterson DJ, Stambe C, Dowling J, Atkins RC, Tesch GH. Abnormal p38 mitogen-activated protein kinase signalling in human and experimental diabetic nephropathy. Diabetologia 2004; 47:1210-1222. [PMID: 15232685 DOI: 10.1007/s00125-004-1437-0] [Citation(s) in RCA: 157] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2004] [Accepted: 03/26/2004] [Indexed: 11/29/2022]
Abstract
AIMS/HYPOTHESIS Inflammation and fibrosis are pathological mechanisms that are partially regulated by cell signalling through the p38 mitogen-activated protein kinase (MAPK) pathway. Elements of the diabetic milieu such as high glucose and advanced glycation end-products induce activation of this pathway in renal cells. Therefore, we examined whether p38 MAPK signalling is associated with the development of human and experimental diabetic nephropathy. METHODS Immunostaining identified phosphorylated (active) p38 MAPK in human biopsies with no abnormality ( n=6) and with Type 2 diabetic nephropathy ( n=12). Changes in kidney levels of phosphorylated p38 were assessed by immunostaining and western blotting in mice with streptozotocin-induced Type 1 diabetes that had been killed after 0.5, 2, 3, 4 and 8 months, and in Type 2 diabetic db/db mice at 2, 4, 6 and 8 months of age. RESULTS Phosphorylated p38 was detected in some intrinsic cells in normal human kidney, including podocytes, cortical tubules and occasional interstitial cells. Greater numbers of these phosphorylated p38+ cells were observed in diabetic patients, and phosphorylated p38 was identified in accumulating interstitial macrophages and myofibroblasts. A similar pattern of p38 activation was observed in both mouse models of diabetes. In mice, kidney levels of phosphorylated p38 increased (2-6 fold) following the onset of Type 1 and Type 2 diabetes. In both mouse models, interstitial phosphorylated p38+ cells were associated with hyperglycaemia, increased HbA(1)c levels and albuminuria. Further assessment of streptozotocin-induced diabetic nephropathy showed that interstitial phosphorylated p38+ cells correlated with interstitial fibrosis (myofibroblasts, collagen). CONCLUSIONS/INTERPRETATION Increased p38 MAPK signalling is a feature of human and experimental diabetic nephropathy. Time course studies in mouse models suggest that phosphorylation of p38 plays a pathological role, particularly in the development of interstitial fibrosis.
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Affiliation(s)
- L Adhikary
- Department of Nephrology, Monash Medical Centre, 246 Clayton Road, Clayton, Victoria 3168, Australia
| | - F Chow
- Department of Nephrology, Monash Medical Centre, 246 Clayton Road, Clayton, Victoria 3168, Australia
- Monash University Department of Medicine, Monash Medical Centre, Clayton, Victoria, Australia
| | - D J Nikolic-Paterson
- Department of Nephrology, Monash Medical Centre, 246 Clayton Road, Clayton, Victoria 3168, Australia
- Monash University Department of Medicine, Monash Medical Centre, Clayton, Victoria, Australia
| | - C Stambe
- Department of Nephrology, Monash Medical Centre, 246 Clayton Road, Clayton, Victoria 3168, Australia
| | - J Dowling
- Department of Anatomical Pathology, Monash Medical Centre, Clayton, Victoria, Australia
| | - R C Atkins
- Department of Nephrology, Monash Medical Centre, 246 Clayton Road, Clayton, Victoria 3168, Australia
- Monash University Department of Medicine, Monash Medical Centre, Clayton, Victoria, Australia
| | - G H Tesch
- Department of Nephrology, Monash Medical Centre, 246 Clayton Road, Clayton, Victoria 3168, Australia.
- Monash University Department of Medicine, Monash Medical Centre, Clayton, Victoria, Australia.
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Wang S, Skorczewski J, Feng X, Mei L, Murphy-Ullrich JE. Glucose up-regulates thrombospondin 1 gene transcription and transforming growth factor-beta activity through antagonism of cGMP-dependent protein kinase repression via upstream stimulatory factor 2. J Biol Chem 2004; 279:34311-22. [PMID: 15184388 DOI: 10.1074/jbc.m401629200] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Thrombospondin 1 (TSP1) transcription is stimulated by glucose, resulting in increased TGF-beta activation and matrix protein synthesis. We previously showed that inducible expression of the catalytic domain of cGMP-dependent protein kinase (PKG) inhibits glucose-regulated TSP1 transcription and transforming growth factor (TGF)-beta activity in stably transfected rat mesangial cells (RMCs(tr/cd)). However, the molecular mechanisms by which PKG represses glucose-regulated TSP1 transcription are unknown. Using a luciferase-promoter deletion assay, we now identify a single region of the human TSP1 promoter (-1172 to -878, relative to the transcription start site) that is responsive to glucose. Further characterization of this region identified an 18-bp sequence that specifically binds nuclear proteins from mesangial cells. Moreover, binding is significantly enhanced by high glucose treatment and is reduced by increased PKG activity. Gel mobility shift and supershift assays show that the nuclear proteins binding to the 18-bp sequence are USF1 and -2. USF1 and USF2 bound to the endogenous TSP1 promoter using a chromatin immunoprecipitation assay. Glucose stimulates nuclear USF2 protein accumulation through protein kinase C, p38 MAPK, and extracellular signal-regulated kinase pathways. Increased PKG activity down-regulates USF2 protein levels and its DNA binding activity under high glucose conditions, resulting in inhibition of glucose-induced TSP1 transcription and TGF-beta activity. Overexpression of USF2 reversed the inhibitory effect of PKG on glucose-induced TSP1 gene transcription and TGF-beta activity. Taken together these data present the first evidence that USF2 mediates glucose-induced TSP1 expression and TSP1-dependent TGF-beta bioactivity in mesangial cells, suggesting that USF2 is an important transcriptional regulator of diabetic complications.
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Affiliation(s)
- Shuxia Wang
- Department of Pathology, Division of Molecular and Cellular Pathology, The Cell Adhesion and Matrix Research Center, University of Alabama at Birmingham, Birmingham, AL 35294-0019, USA
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Kang SW, Natarajan R, Shahed A, Nast CC, LaPage J, Mundel P, Kashtan C, Adler SG. Role of 12-Lipoxygenase in the Stimulation of p38 Mitogen-Activated Protein Kinase and Collagen α5(IV) in Experimental Diabetic Nephropathy and in Glucose-Stimulated Podocytes. J Am Soc Nephrol 2003; 14:3178-87. [PMID: 14638916 DOI: 10.1097/01.asn.0000099702.16315.de] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
ABSTRACT. The 12-lipoxygenase (12-LO) pathway of arachidonic acid metabolism is implicated in extracellular matrix (ECM) synthesis, but its role in podocytes has not been studied. This study tested whether 12-LO induction by diabetes or by high glucose (HG) in cultured podocytes alters glomerular basement membrane by activating signal transduction pathways culminating in ECM synthesis. Sprague-Dawley rats received an injection of diluent (control [C]) or streptozotocin 65 mg/kg (DM) and were killed at 1 or 4 mo. Glomerular 12-LO mRNA and protein levels were higher in DM than in C glomeruli at 1 and 4 mo, and 12-LO localized predominantly in podocytes. Glomerular p38 mRNA and protein were higher in DM at months 1 and 4, but phospho-p38 mitogen-activated protein (MAPK) was increased only at month 1. Glomerular collagen α5(IV)/glutaraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA ratio was increased in DM at month 1 but not at month 4, whereas collagen α5(IV) protein was higher at both 1 and 4 mo. Mouse podocytes were cultured in media with 25 mM glucose (HG) with or without the 12-LO inhibitor cinnamyl-3,4-dihydroxy-cyanocinnamate (CDC) or with 5.5 mM glucose + 19.5 mM mannitol (low glucose [LG+M]) for 10 d at 37°C. 12-LO mRNA and protein levels were higher in HG than in LG+M as was the p38 MAPK/GAPDH mRNA ratio. Phospho-p38 MAPK protein but not total p38 MAPK was higher in HG compared with LG+M. Collagen α5(IV)/GAPDH mRNA ratio and protein were higher in HG than in LG+M. 12-LO inhibition by CDC decreased HG-induced phospho-p38 MAPK and the phospho-p38/total p38 MAPK ratio, collagen α5(IV)/GAPDH mRNA ratio, and collagen α5(IV) protein expression. In summary, diabetes in vivo and exposure of podocytes to HG in vitro stimulated 12-LO, p38 MAPK, and collagen α5(IV) mRNA and (activated) protein. 12-LO inhibition by CDC diminished the expression of podocyte phospho-p38 MAPK and collagen α5(IV) mRNA and protein. These findings implicate 12-LO and the p38 MAPK signaling pathway in the mediation of ECM synthesis by podocytes in diabetes.
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Affiliation(s)
- Shin-Wook Kang
- Division of Nephrology and Hypertension, Department of Internal Medicine, Harbor-UCLA Research and Education Institute, Torrance, California 90509, USA
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Li HY, Chang SP, Yuan CC, Chao HT, Ng HT, Sung YJ. Induction of p38 mitogen-activated protein kinase-mediated apoptosis is involved in outgrowth of trophoblast cells on endometrial epithelial cells in a model of human trophoblast-endometrial interactions. Biol Reprod 2003; 69:1515-24. [PMID: 12826588 DOI: 10.1095/biolreprod.103.015669] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
During embryo implantation in species with hemochorial placentation, such as the mouse and human, trophoblast cells of the attached blastocyst penetrate the luminal epithelium of the endometrium before invasion into the endometrial stroma. Signs of apoptosis were demonstrated in luminal endometrial epithelial cells (EEC) adjacent to the trophoblast cells; however, the signaling mechanisms leading to apoptosis in EEC remain unclear. Because mitogen-activated protein kinases (MAPK) were shown to mediate apoptosis in several model systems and found to be activated in the uterus during decidualization, the possible involvement of MAPK during trophoblast-EEC interactions was studied. By coculturing BeWo human trophoblast spheroids with RL95-2 human EEC monolayers to mimic the blastocyst-endometrial interaction, we found that most spheroids rapidly attached to EEC monolayers and then progressively expanded, with marked dislodgment of EEC adjacent to the spreading trophoblast cells. Immunoblotting analysis showed that both p38 MAPK and extracellular signal-regulated kinase (ERK) were activated in EEC after coculture. However, only SB203580 (a p38 MAPK inhibitor), but not PD98059 (an ERK inhibitor), inhibited trophoblast outgrowth on EEC monolayers through the suppression of p38 MAPK activation in EEC. Furthermore, trophoblast expansion caused prominent EEC apoptosis at the spheroid-EEC interface, as detected by annexin V labeling and valyl-alanyl-aspartyl-[O-methyl]-fluoromethylketone (which binds activated caspases) staining, and SB203580 significantly decreased the percentage of apoptotic cells. Our results, based on a model of human trophoblast-EEC interactions, establish that trophoblast cells cause activation of p38 MAPK in EEC and, consequently, induce apoptosis and displacement of EEC, a process that may facilitate implantation.
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Kim YS, Reddy MA, Lanting L, Adler SG, Natarajan R. Differential behavior of mesangial cells derived from 12/15-lipoxygenase knockout mice relative to control mice11See Editorial by Kasinath, p. 1918. Kidney Int 2003; 64:1702-14. [PMID: 14531803 DOI: 10.1046/j.1523-1755.2003.00286.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND The 12/15-lipoxygenase (12/15-LO) enzyme has been implicated in the pathogenesis of diabetic nephropathy since lipoxygenase products induce cellular hypertrophy and extracellular matrix deposition in mesangial cells. In this study, in order to determine the potential in vivo functional role of 12/15-LO in kidney disease, we compared mouse mesangial cells (MMCs) derived from 12/15-LO knockout mice with those from genetic control wild-type mice. METHODS MMCs were isolated from wild-type and 12/15-LO knockout mice. Cellular growth, activation of mitogen-activated protein kinases (MAPKs), transcription factors, superoxide levels, and fibronectin expression were compared in the two cell types. RESULTS Levels of the 12/15-LO product and protein were lower in MMC from 12/15-LO knockout relative to wild-type. MMCs from 12/15-LO knockout mice grew slower than wild-type cells, and also showed lower rates of tritiated thymidine and leucine incorporation (21% and 15% of wild-type, respectively, P < 0.001). Levels of superoxide and the matrix protein fibronectin were also lower in 12/15-LO knockout mice cells. Serum and angiotensin II (Ang II)-stimulated activities of p38 or ERK1/2 MAPKs, and cyclic adenosine monophosphate (cAMP)-responsive element binding protein (CREB) transcription factor were lower in 12/15-LO knockout relative to wild-type cells. In addition, DNA binding and transcriptional activities of activated protein-1 (AP-1) and CREB were lower in 12/15-LO knockout cells. Furthermore, stable 12/15-LO overexpression in MMC led to reciprocal increase in p38 MAPK activation and fibronectin expression. CONCLUSION The differential activation of oxidant stress, specific signaling pathways, transcription factors, and growth and matrix genes may lead to reduced growth and growth factor responses in 12/15-LO knockout versus wild-type MMCs. These results provide ex vivo functional evidence for the first time that 12/15-LO activation plays a key role in mesangial cell responses associated with renal diseases such as diabetic nephropathy.
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Affiliation(s)
- Young-Sook Kim
- Gonda Diabetes Research Center, Beckman Research Institute of the City of Hope, Duarte, California 91010, USA
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Haneda M, Koya D, Isono M, Kikkawa R. Overview of glucose signaling in mesangial cells in diabetic nephropathy. J Am Soc Nephrol 2003; 14:1374-82. [PMID: 12707407 DOI: 10.1097/01.asn.0000064500.89551.76] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Affiliation(s)
- Masakazu Haneda
- Department of Medicine, Shiga University of Medical Science, Seta, Otsu, Shiga 520-2192, Japan.
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Abstract
PURPOSE OF REVIEW Diabetic nephropathy is the single most common disorder leading to renal failure. Its annual incidence has more than doubled in the past decade to reach 44% of all end-stage renal disease, despite recent therapeutic advances. Thus, research into diabetic nephropathy pathophysiology that could lead to new treatment approaches is urgently needed and this review aims to summarize the work performed in this area in the past year. RECENT FINDINGS There have been advances in the understanding of diabetic nephropathy pathology. Clearly, structural changes may be advanced before any clinical findings are apparent. Not all functional consequences of the condition are explained by current structural analyses. Genetic studies have connected the disorder risk to multiple candidate genes and a few genetic loci, but the exact genetic predisposition or protectors are not fully described. Perturbations in multiple metabolic pathways are associated with diabetic nephropathy in animals and humans, but their relative importance requires further work. Glycemia and blood pressure control are crucial for diabetic nephropathy prevention and treatment, but new modalities are needed. SUMMARY Recent advances in molecular biology and genetics will bring new insights to the mechanisms involved in diabetic nephropathy development. This will allow early identification of patients at risk of, or safe from, diabetic nephropathy and will hopefully lead to preventive strategies, based on the understanding of the pathophysiology of the disorder. Meanwhile, aggressive implementation of proven therapies to prevent (glycemic control) and slow (antihypertensive therapy, especially with renin-angiotensin system blockers) the progression of diabetic nephropathy are strongly recommended.
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Affiliation(s)
- M Luiza Caramori
- Endocrine Division, Universidade Federal do Rio Grande do Sul, Brazil and bDepartment of Pediatrics, University of Minnesota, Minneapolis, Minnesota 55455, USA
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Imai G, Satoh T, Kumai T, Murao M, Tsuchida H, Shima Y, Ogimoto G, Fujino T, Kobayashi S, Kimura K. Hypertension accelerates diabetic nephropathy in Wistar fatty rats, a model of type 2 diabetes mellitus, via mitogen-activated protein kinase cascades and transforming growth factor-beta1. Hypertens Res 2003; 26:339-47. [PMID: 12733703 DOI: 10.1291/hypres.26.339] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Although it is known that diabetic nephropathy is accelerated by hypertension, the mechanisms involved in this process are not clear. In this study we aimed to clarify these mechanisms using male Wistar fatty rats (WFR) as a type 2 diabetic model and male Wistar lean rats (WLR) as a control. Each group was fed a normal or high sodium diet from the age of 6 to 14 weeks. We determined the blood pressure and urinary albumin excretion (UAE). At the end of the study, the expressions of mitogen-activated protein kinases (MAPK) and transforming growth factor-beta1 (TGF-beta1) were examined in the isolated glomeruli by Western blot analysis, and the number of glomerular lesions was determined by conventional histology. High sodium load caused hypertension and a marked increase in UAE in the WFR but not in the WLR. Glomerular volume was increased in the hypertensive WFR. There was no difference among the four groups in the expression of c-Jun-NH2-terminal kinase (JNK). In contrast, the expressions of extracellular signal-regulated kinase 1/2 (ERK1/2) and its upstream regulator, MAPK/ERK kinase 1 (MEK1), were augmented in the hypertensive WFR. Expression of p38 MAPK was increased in the normotensive WFR, and further enhanced in the hypertensive WFR. Moreover, administration of high sodium load to WFR augmented the expression of TGF-beta1. In conclusion, systemic hypertension in WFR accelerates the diabetic nephropathy in type 2 diabetes via MEK-ERK and p38 MAPK cascades. TGF-beta1 is also involved in this mechanism.
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Affiliation(s)
- Goro Imai
- Division of Nephrology and Hypertension, Department of Internal Medicine, St. Marianna University School of Medicine, Kawasaki, Japan
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Reddy MA, Adler SG, Kim YS, Lanting L, Rossi J, Kang SW, Nadler JL, Shahed A, Natarajan R. Interaction of MAPK and 12-lipoxygenase pathways in growth and matrix protein expression in mesangial cells. Am J Physiol Renal Physiol 2002; 283:F985-94. [PMID: 12372774 DOI: 10.1152/ajprenal.00181.2002] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The lipoxygenase (LO) pathway of arachidonate metabolism and mitogen-activated protein kinases (MAPKs) can mediate cellular growth and ANG II effects in vascular smooth muscle cells. However, their role in renal mesangial cells (MC) is not very clear. ANG II treatment of rat MC significantly increased 12-LO mRNA expression and formation of the 12-LO product 12(S)-hydroxyeicosatetraenoic acid [12(S)-HETE; P < 0.03]. ANG II-induced [(3)H]leucine incorporation was blocked by an LO inhibitor, cinnamyl-3,4-dihydroxy-alpha-cyanocinnamate (P < 0.02). 12(S)-HETE and ANG II directly induced cellular hypertrophy and fibronectin (FN) expression (P < 0.01) to a similar extent. ANG II and 12(S)-HETE led to activation of p38(MAPK) and its target transcription factor cAMP-responsive element-binding protein (CREB). ANG II- and 12(S)-HETE-induced CREB activation and [(3)H]leucine incorporation were blocked by the p38(MAPK) inhibitor SB-202190. A specific molecular inhibitor of rat 12-LO mRNA, namely, a novel ribozyme, could attenuate ANG II-induced FN mRNA. Thus p38(MAPK)-dependent CREB activation may mediate ANG II- and LO product-induced FN expression and cellular growth in rat MC. ANG II effects may be mediated by the LO pathway. These results suggest a novel interaction between LO and p38(MAPK) activation in MC matrix synthesis associated with renal complications.
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Affiliation(s)
- Marpadga A Reddy
- Department of Diabetes, Beckman Research Institute of the City of Hope, Duarte California 91010, USA
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