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Han W, Wang C, Yang Z, Mu L, Wu M, Chen N, Du C, Duan H, Shi Y. SRT1720 retards renal fibrosis via inhibition of HIF1α /GLUT1 in diabetic nephropathy. J Endocrinol 2019; 241:JOE-18-0536.R2. [PMID: 30798323 DOI: 10.1530/joe-18-0536] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 02/22/2019] [Indexed: 12/17/2022]
Abstract
Renal fibrosis is a major pathological characteristic of diabetic nephropathy (DN). Reportedly, increased SIRT1 expression played a renal protective role in animal models of DN. This study was designed to elucidate the molecular mechanisms underlying the protective effects of SRT1720, an SIRT1 activator, against diabetes-induced renal fibrosis. Type 2 diabetic mice (db/db) were treated with SRT1720 (50 mg/kg/d) by gavage for 10 weeks. Renal proximal tubular epithelial cells (HK-2 cells) were treated with high glucose (HG, 30 mM) in the presence or absence of SRT1720 (2.5 µM) for 48 h. We observed that impaired SIRT1 expression and activity were restored by SRT1720 administration in db/db mice as well as in HG-treated HK-2 cells. Moreover, SRT1720 administration improved renal function, attenuated glomerular hypertrophy, mesangial expansion, glomerulosclerosis and interstitial fibrosis, and inhibited TGFB1 and CTGF expressions and nuclear factor κB (NF-κB) activation in db/db mice. Similarly, HG-induced epithelial-to-mesenchymal transformation (EMT), and collagen IV and fibronectin expressions were inhibited in SRT1720 treated HK-2 cells. Mechanistic studies demonstrated that SRT1720 suppressed HIF1α, GLUT1 and SNAIL expressions both in vivo and in vitro. Furthermore, Hif1α or Glut1 knockdown effectively abrogated HG-induced EMT and collagen IV and fibronectin expressions in HK-2 cells. These findings suggest that SRT1720 prevented diabetes-induced renal fibrosis via the SIRT1/HIF1α/GLUT1/SNAIL pathway.
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Affiliation(s)
- Weixia Han
- W Han, Department of Pathology, Hebei Medical University, Shijiazhuang City, China
| | - Chen Wang
- C Wang, Department of Pathology, Shanxi Medical University Second Affiliated Hospital, Taiyuan, China
| | - Zhifen Yang
- Z Yang, Department of pathology , Hebei Medical University, Shijiazhuang City, China
| | - Lin Mu
- L Mu, Department of Pathology, Hebei Medical University, Shijiazhuang City, China
| | - Ming Wu
- M Wu, Department of Pathology, Hebei Medical University, Shijiazhuang City, China
| | - Nan Chen
- N Chen, Department of Pathology, Hebei Medical University, Shijiazhuang City, China
| | - Chunyang Du
- C Du, Department of Pathology, Hebei Medical University, Shijiazhuang City, China
| | - Huijun Duan
- H Duan, Department of Pathology, Hebei Medical University, Shijiazhuang City, China
| | - Yonghong Shi
- Y Shi, Department of Pathology, Hebei Medical University, Shijiazhuang City, 050017, China
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Nayak BK, Shanmugasundaram K, Friedrichs WE, Cavaglierii RC, Patel M, Barnes J, Block K. HIF-1 Mediates Renal Fibrosis in OVE26 Type 1 Diabetic Mice. Diabetes 2016; 65:1387-97. [PMID: 26908870 PMCID: PMC4839204 DOI: 10.2337/db15-0519] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 01/19/2016] [Indexed: 12/19/2022]
Abstract
Hypoxia-inducible factor (HIF)-1 mediates hypoxia- and chronic kidney disease-induced fibrotic events. Here, we assessed whether HIF-1 blockade attenuates the manifestations of diabetic nephropathy in a type 1 diabetic animal model, OVE26. YC-1 [3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole], an HIF-1 inhibitor, reduced whole kidney glomerular hypertrophy, mesangial matrix expansion, extracellular matrix accumulation, and urinary albumin excretion as well as NOX4 protein expression and NADPH-dependent reactive oxygen species production, while blood glucose levels remained unchanged. The role of NOX oxidases in HIF-1-mediated extracellular matrix accumulation was explored in vitro using glomerular mesangial cells. Through a series of genetic silencing and adenoviral overexpression studies, we have defined GLUT1 as a critical downstream target of HIF-1α mediating high glucose-induced matrix expression through the NADPH oxidase isoform, NOX4. Together, our data suggest that pharmacological inhibition of HIF-1 may improve clinical manifestations of diabetic nephropathy.
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Affiliation(s)
- Bijaya K Nayak
- Department of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX
| | | | - William E Friedrichs
- Department of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX
| | - Rita C Cavaglierii
- Department of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX
| | - Mandakini Patel
- Department of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX
| | - Jeffrey Barnes
- Department of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX Audie L. Murphy Memorial VA Hospital Division, South Texas Veterans Health Care System, San Antonio, TX
| | - Karen Block
- Department of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX Audie L. Murphy Memorial VA Hospital Division, South Texas Veterans Health Care System, San Antonio, TX
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Abstract
TGF-β is well known to play a critical role in diabetic kidney disease, and ongoing clinical studies are testing the potential therapeutic promise of inhibiting TGF-β production and action. An aspect of TGF-β action that has not received much attention is its potential role in explaining sex-related proclivity for kidney disease. In this review, we discuss recent studies linking TGF-β signaling to sex-related effects in diabetic kidney disease and suggest targets for future studies.
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Affiliation(s)
- Maggie K Diamond-Stanic
- Center for Renal Translational Medicine, University of California San Diego/Veterans Affairs San Diego Healthcare System, La Jolla, CA 92093-0711, USA
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Buller CL, Heilig CW, Brosius FC. GLUT1 enhances mTOR activity independently of TSC2 and AMPK. Am J Physiol Renal Physiol 2011; 301:F588-96. [PMID: 21613414 DOI: 10.1152/ajprenal.00472.2010] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Enhanced GLUT1 expression in mesangial cells plays an important role in the development of diabetic nephropathy by stimulating signaling through several pathways resulting in increased glomerular matrix accumulation. Similarly, enhanced mammalian target of rapamycin (mTOR) activation has been implicated in mesangial matrix expansion and glomerular hypertrophy in diabetes. We sought to examine whether enhanced GLUT1 expression increased mTOR activity and, if so, to identify the mechanism. We found that levels of GLUT1 expression and mTOR activation, as evidenced by S6 kinase (S6K) and 4E-BP-1 phosphorylation, changed in tandem in cell lines exposed to elevated levels of extracellular glucose. We then showed that increased GLUT1 expression enhanced S6K phosphorylation by 1.7- to 2.9-fold in cultured mesangial cells and in glomeruli from GLUT1 transgenic mice. Treatment with the mTOR inhibitor, rapamycin, eliminated the GLUT1 effect on S6K phosphorylation. In cells lacking functional tuberous sclerosis complex (TSC) 2, GLUT1 effects on mTOR activity persisted, indicating that GLUT1 effects were not mediated by TSC. Similarly, AMP kinase activity was not altered by enhanced GLUT1 expression. Conversely, enhanced GLUT1 expression led to a 2.4-fold increase in binding of mTOR to its activator, Rheb, and a commensurate 2.1-fold decrease in binding of Rheb to glyceraldehyde 3-phosphate dehydrogenase (GAPDH) consistent with mediation of GLUT1 effects by a metabolic effect on GAPDH. Thus, GLUT1 expression appears to augment mesangial cell growth and matrix protein accumulation via effects on glycolysis and decreased GAPDH interaction with Rheb.
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Affiliation(s)
- Carolyn L Buller
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, USA
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Wang Y, Heilig K, Saunders T, Minto A, Deb DK, Chang A, Brosius F, Monteiro C, Heilig CW. Transgenic overexpression of GLUT1 in mouse glomeruli produces renal disease resembling diabetic glomerulosclerosis. Am J Physiol Renal Physiol 2010; 299:F99-F111. [PMID: 20375117 DOI: 10.1152/ajprenal.00466.2009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Previous work identified an important role for hyperglycemia in diabetic nephropathy (The Diabetes Control and Complications Trial Research Group. N Engl J Med 329: 977-986, 1993; UK Prospective Diabetes Study Group. Lancet 352: 837-853, 1998), and increased glomerular GLUT1 has been implicated. However, the roles of GLUT1 and intracellular glucose have not been determined. Here, we developed transgenic GLUT1-overexpressing mice (GT1S) to characterize the roles of GLUT1 and intracellular glucose in the development of glomerular disease without diabetes. GLUT1 was overexpressed in glomerular mesangial cells (MC) of C57BL6 mice, a line relatively resistant to diabetic nephropathy. Blood pressure, blood glucose, glomerular morphometry, matrix proteins, cell signaling, transcription factors, and selected growth factors were examined. Kidneys of GT1S mice overexpressed GLUT1 in glomerular MCs and small vessels, rather than renal tubules. GT1S mice were neither diabetic nor hypertensive. Glomerular GLUT1, glucose uptake, mean capillary diameter, and mean glomerular volume were all increased in the GT1S mice. Moderately severe glomerulosclerosis (GS) was established by 26 wk of age in GT1S mice, with increased glomerular type IV collagen and fibronectin. Modest increases in glomerular basement membrane thickness and albuminuria were detected with podocyte foot processes largely preserved, in the absence of podocyte GLUT1 overexpression. Activation of glomerular PKC, along with increased transforming growth factor-beta1, VEGFR1, VEGFR2, and VEGF were all detected in glomeruli of GT1S mice, likely contributing to GS. The transcription factor NF-kappaB was also activated. Overexpression of glomerular GLUT1, mimicking the diabetic GLUT1 response, produced numerous features typical of diabetic glomerular disease, without diabetes or hypertension. This suggested GLUT1 may play an important role in the development of diabetic GS.
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Affiliation(s)
- Youli Wang
- Department of Medicine and Pathology, University of Chicago, Chicago, Illinois, USA
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Abstract
Perspectives on the News commentaries are part of a free monthly CME activity. The Mount Sinai School of Medicine, New York, New York, designates this activity for 2.0 AMA PRA Category 1 credits. If you wish to participate, review this article and visit www.diabetes.procampus.net to complete a posttest and receive a certificate. The Mount Sinai School of Medicine is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing medical education for physicians.
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Pugliese G, Ricci C, Iacobini C, Menini S, Fioretto P, Ferrandi M, Giardino LA, Armelloni S, Mattinzoli D, Rastaldi MP, Pugliese F. Glomerular barrier dysfunction in glomerulosclerosis- resistant Milan rats with experimental diabetes: the role of renal haemodynamics. J Pathol 2007; 213:210-8. [PMID: 17768702 DOI: 10.1002/path.2226] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Rats of the Milan hypertensive strain (MHS) are resistant to both hypertensive and diabetic renal disease. Genetically determined hypertrophy of intrarenal arteries has been suggested as the putative mechanism preventing transmission of systemic hypertension to the glomerular microcirculation or diabetes-induced loss of autoregulation, which lead to glomerular hypertension and consequent podocyte injury and proteinuria. This study aimed to investigate glomerular barrier function and structure in ageing and diabetic MHS rats under basal conditions and after injection of 2.5 g of bovine serum albumin (BSA) causing increased workload and possibly removing haemodynamic protection by inducing renal cortical vasodilatation. Genetically related rats of the Milan normotensive strain (MNS) served as a proteinuric counterpart. No change in renal function or structure was detected in diabetic MHS rats, whereas MNS rats developed diabetic nephropathy superimposed on that occurring spontaneously in this strain. Diabetic, but not non-diabetic, MHS rats showed significantly reduced synaptopodin and nephrin expression, though to a lesser extent than non-diabetic and diabetic MNS rats, together with unchanged podocyte number, density and structure and no proteinuria. Agrin expression was significantly altered in diabetic versus non-diabetic MHS animals, whereas collagen I was expressed only in diabetic MHS rats and collagen IV content did not change significantly between the two groups. Upon BSA injection, proteinuria increased markedly and abundant BSA was detected only in kidneys from diabetic MHS rats. BSA injection was associated with changes in intrarenal arteries suggesting vasodilatation, without any influx of inflammatory cells. These data indicate that while MNS rats show marked changes in the glomerular filtration barrier with either age or diabetes, glomerulosclerosis-resistant MHS rats develop only minor diabetes-induced podocyte (and extracellular matrix) alterations, which are not associated with proteinuria unless they are unmasked by an increased workload or removal of the haemodynamic protection.
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Affiliation(s)
- G Pugliese
- Department of Clinical Sciences, La Sapienza University, Rome, Italy.
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Gnudi L, Thomas SM, Viberti G. Mechanical forces in diabetic kidney disease: a trigger for impaired glucose metabolism. J Am Soc Nephrol 2007; 18:2226-32. [PMID: 17634438 DOI: 10.1681/asn.2006121362] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Nephropathy is one of the major microvascular complications of diabetes, and both hemodynamic and metabolic stimuli participate in its development and progression toward ESRD. There is now a greater understanding of the molecular pathways that are activated by high glomerular capillary pressure and hyperglycemia and how they interplay to produce kidney pathology. The observation that overexpression of glucose transporter 1 (GLUT-1) in mesangial cells could induce a "diabetic cellular phenotype" has led to the postulation that the expression of GLUT-1 could be upregulated in glomeruli that are exposed to high pressure. This review suggests a mechanism by which mechanical forces may aggravate a metabolic insult by stimulating excessive cellular glucose uptake. Proposed is the existence of a self-maintaining cycle whereby a hemodynamic stimulus on glomerular cells induces GLUT-1 overexpression followed by greater glucose uptake and activation of intracellular glucose metabolic pathways, resulting in excess TGF-beta1 production. TGF-beta1 in turn, maintains overexpression of GLUT-1, perpetuating a signaling sequence that has, as its ultimate effect, increased extracellular matrix synthesis. This mechanical and metabolic coupling suggests a novel pathophysiologic mechanism of injury in the kidney in diabetes and possibly other glomerular diseases.
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Affiliation(s)
- Luigi Gnudi
- Cardiovascular Division, King's College London, Guy's Hospital, London SE1 9RT, UK.
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Hills CE, Bland R, Bennett J, Ronco PM, Squires PE. High Glucose Up-Regulates ENaC and SGK1 Expression in HCD-Cells. Cell Physiol Biochem 2006; 18:337-46. [PMID: 17170520 DOI: 10.1159/000097611] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/18/2006] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIM Diabetic nephropathy is associated with progressive renal damage, leading to impaired function and end-stage renal failure. Secondary hypertension stems from a deranged ability of cells within the kidney to resolve and appropriately regulate sodium resorption in response to hyperglycaemia. However, the mechanisms by which glucose alters sodium re-uptake have not been fully characterised. METHODS Here we present RT-PCR, western blot and immunocytochemistry data confirming mRNA and protein expression of the serum and glucocorticoid inducible kinase (SGK1) and the alpha conducting subunit of the epithelial sodium channel (ENaC) in a model in vitro system of the human cortical collecting duct (HCD). We examined changes in expression of these elements in response to glucose challenge, designed to mimic hyperglycaemia associated with type 2 diabetes mellitus. Changes in Na+ concentration were assessed using single-cell microfluorimetry. RESULTS Incubation with glucose, the Ca2+-ionophore ionomycin and the cytokine TGF-beta1 were all found to evoke significant and time-dependent increases in both SGK1 and alphaENaC protein expression. These molecular changes were correlated to an increase in Na+-uptake at the single-cell level. CONCLUSION Together these data offer a potential explanation for glucose-evoked Na+-resorption and a potential contributory role of SGK1 and ENaCs in development of secondary hypertension, commonly linked to diabetic nephropathy.
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Affiliation(s)
- Claire E Hills
- Molecular Physiology, Biomedical Research Institute, Department of Biological Sciences, University of Warwick, Coventry, UK
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