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Xie X, Chang X, Chen L, Huang K, Huang J, Wang S, Shen X, Liu P, Huang H. Berberine ameliorates experimental diabetes-induced renal inflammation and fibronectin by inhibiting the activation of RhoA/ROCK signaling. Mol Cell Endocrinol 2013; 381:56-65. [PMID: 23896433 DOI: 10.1016/j.mce.2013.07.019] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 06/15/2013] [Accepted: 07/19/2013] [Indexed: 01/26/2023]
Abstract
The accumulation of glomerular extracellular matrix proteins, especially fibronectin (FN), is a critical pathological characteristic of diabetic renal fibrosis. Inflammation mediated by nuclear factor-κB (NF-κB) plays a critical role in the pathogenesis of diabetic nephropathy (DN). RhoA/ROCK signaling is responsible for FN accumulation and NF-κB activation. Berberine (BBR) treatment significantly inhibited renal inflammation and thus improved renal damage in diabetes. Here, we study whether BBR inhibits FN accumulation and NF-κB activation by inhibiting RhoA/ROCK signaling and the underlying mechanisms involved. Results showed that BBR effectively inhibited RhoA/ROCK signaling activation in diabetic rat kidneys and high glucose-induced glomerular mesangial cells (GMCs) and simultaneously down-regulated NF-κB activity, which was accompanied by reduced intercellular adhesionmolecule-1, transforming growth factor-beta 1 and FN overproduction. Furthermore, we observed that BBR abrogated high glucose-mediated reactive oxygen species generation in GMCs. BBR and N-acetylcysteine inhibited RhoA/ROCK signaling activation in high glucose-exposed GMCs. Collectively, our data suggest that the renoprotective effect of BBR on DN partly depends on RhoA/ROCK inhibition. The anti-oxidative stress effect of BBR is responsible for RhoA/ROCK inhibition in DN.
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Affiliation(s)
- Xi Xie
- Laboratory of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China; Department of Pharmaceutical Engineering, Ocean College, Hainan University, Haikou 570228, China
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Huang K, Huang J, Xie X, Wang S, Chen C, Shen X, Liu P, Huang H. Sirt1 resists advanced glycation end products-induced expressions of fibronectin and TGF-β1 by activating the Nrf2/ARE pathway in glomerular mesangial cells. Free Radic Biol Med 2013; 65:528-540. [PMID: 23891678 DOI: 10.1016/j.freeradbiomed.2013.07.029] [Citation(s) in RCA: 209] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 06/20/2013] [Accepted: 07/19/2013] [Indexed: 02/06/2023]
Abstract
Advanced glycation end products (AGEs) boost the generation of reactive oxygen species (ROS) in glomerular mesangial cells (GMCs), and thereby play important roles in diabetic nephropathy (DN). Sirtuin 1 (Sirt1), a protein deacetylase, is known to markedly protect cells from oxidative stress (OSS) injury. Based on the critical involvements of AGEs and Sirt1 in OSS, Sirt1 is postulated to resist AGEs-induced diabetic renal fibrosis through its antioxidative effects. The current study was designed to explore the inhibitory effect of Sirt1 on the expressions of fibronectin (FN) and transforming growth factor-β1 (TGF-β1) induced by AGEs in GMCs. The molecular mechanism by which Sirt1 promoted the activation of the antioxidative pathway was further investigated. The following findings were obtained: (1) the treatment of GMCs with AGEs decreased Sirt1 levels in terms of protein expression and activity but increased FN and TGF-β1 levels in a dose- and time-dependent manner; (2) resveratrol or Sirt1 overexpression markedly increased Sirt1 levels and reduced FN and TGF-β1 expressions; (3) inhibition of Sirt1 activity further induced the productions of FN and TGF-β1; (4) Sirt1 promoted the nuclear accumulation, DNA binding, and transcriptional activities of Nrf2 and upregulated the expressions of Nrf2 downstream genes, heme oxygenase-1, and superoxide dismutase 1; ROS levels induced by AGEs eventually reduced in a deacetylase-dependent manner; and (5) with the deposition of AGEs in the kidneys, the diabetic rats suffered severe renal dysfunction and high OSS levels; resveratrol treatment evidently diminished the OSS levels, ameliorated renal injury, and prevented the expressions of FN and TGF-β1 in the kidneys of diabetic rats. This work supports a negative role of Sirt1 in AGE-induced overproductions of FN and TGF-β1. The molecular mechanisms that underlie the beneficial effects of Sirt1 on DN correlate well with the activation of the Nrf2/ARE antioxidative pathway.
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Affiliation(s)
- Kaipeng Huang
- Laboratory of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, 132 East Circle at University Town, Guangzhou, 510006, China
| | - Juan Huang
- Laboratory of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, 132 East Circle at University Town, Guangzhou, 510006, China
| | - Xi Xie
- Laboratory of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, 132 East Circle at University Town, Guangzhou, 510006, China
| | - Shaogui Wang
- Laboratory of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, 132 East Circle at University Town, Guangzhou, 510006, China
| | - Cheng Chen
- Laboratory of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, 132 East Circle at University Town, Guangzhou, 510006, China
| | - Xiaoyan Shen
- Laboratory of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, 132 East Circle at University Town, Guangzhou, 510006, China
| | - Peiqing Liu
- Laboratory of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, 132 East Circle at University Town, Guangzhou, 510006, China
| | - Heqing Huang
- Laboratory of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, 132 East Circle at University Town, Guangzhou, 510006, China.
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Lan T, Wu T, Gou H, Zhang Q, Li J, Qi C, He X, Wu P, Wang L. Andrographolide suppresses high glucose-induced fibronectin expression in mesangial cells via inhibiting the AP-1 pathway. J Cell Biochem 2013; 114:2562-8. [DOI: 10.1002/jcb.24601] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 05/21/2013] [Indexed: 12/20/2022]
Affiliation(s)
- Tian Lan
- Vascular Biology Research Institute; Guangdong Pharmaceutical University; Guangzhou; 510006; China
| | - Teng Wu
- Vascular Biology Research Institute; Guangdong Pharmaceutical University; Guangzhou; 510006; China
| | - Hongju Gou
- Department of Pathology, School of Basic Medical Sciences; Southern Medical University; Guangzhou; 510515; China
| | - Qianqian Zhang
- Vascular Biology Research Institute; Guangdong Pharmaceutical University; Guangzhou; 510006; China
| | - Jiangchao Li
- Vascular Biology Research Institute; Guangdong Pharmaceutical University; Guangzhou; 510006; China
| | - Cuiling Qi
- Vascular Biology Research Institute; Guangdong Pharmaceutical University; Guangzhou; 510006; China
| | - Xiaodong He
- Vascular Biology Research Institute; Guangdong Pharmaceutical University; Guangzhou; 510006; China
| | - Pingxiang Wu
- Department of Pathology, School of Basic Medical Sciences; Southern Medical University; Guangzhou; 510515; China
| | - Lijing Wang
- Vascular Biology Research Institute; Guangdong Pharmaceutical University; Guangzhou; 510006; China
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Xie X, Lan T, Chang X, Huang K, Huang J, Wang S, Chen C, Shen X, Liu P, Huang H. Connexin43 mediates NF-κB signalling activation induced by high glucose in GMCs: involvement of c-Src. Cell Commun Signal 2013; 11:38. [PMID: 23718910 PMCID: PMC3699363 DOI: 10.1186/1478-811x-11-38] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 05/10/2013] [Indexed: 12/23/2022] Open
Abstract
Background Nuclear factor kappa-B (NF-κB) signalling plays an important role in diabetic nephropathy. Altered expression of connexin43 (Cx43) has been found in kidneys of diabetic animals. The aim of the current study was to investigate the role of Cx43 in the activation of NF-κB induced by high glucose in glomerular mesangial cells (GMCs) and to determine whether c-Src is involved in this process. Results We found that downregulation of Cx43 expression induced by high glucose activated NF-κB in GMCs. Orverexpression of Cx43 attenuated NF-κB p65 nuclear translocation induced by high glucose. High glucose inhibited the interaction between Cx43 and c-Src, and enhanced the interaction between c-Src and IκB-α. PP2, a c-Src inhibitor, also inhibited the tyrosine phosphorylation of IκB-α and NF-κB p65 nuclear translocation induced by high glucose. Furthermore, overexpression of Cx43 or inhibition of c-Src attenuated the upregulation of intercellular adhesion molecule-1 (ICAM-1), transforming growth factor-beta 1 (TGF-β1) and fibronectin (FN) expression induced by high glucose. Conclusions In conclusion, downregulation of Cx43 in GMCs induced by high glucose activates c-Src, which in turn promotes interaction between c-Src and IκB-α and contributes to NF-κB activation in GMCs, leading to renal inflammation.
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Affiliation(s)
- Xi Xie
- Laboratory of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China.
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Xie X, Peng J, Chang X, Huang K, Huang J, Wang S, Shen X, Liu P, Huang H. Activation of RhoA/ROCK regulates NF-κB signaling pathway in experimental diabetic nephropathy. Mol Cell Endocrinol 2013; 369:86-97. [PMID: 23376009 DOI: 10.1016/j.mce.2013.01.007] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Revised: 01/10/2013] [Accepted: 01/13/2013] [Indexed: 10/27/2022]
Abstract
Both RhoA/ROCK and NF-κB signaling pathways play important roles in the pathogenesis of diabetic nephropathy (DN). However, it remains unknown whether and how RhoA/ROCK regulates NF-κB signaling in diabetic kidneys. In cultured glomerular mesangial cells (GMCs), the high glucose-activated NF-κB nuclear translocation and DNA binding activity were attenuated by ROCK inhibitor Y27632 or dominant-negative RhoA mutant, indicating that RhoA/ROCK signaling regulates high glucose-activated NF-κB pathway. Furthermore, NF-κB-regulated inflammatory factors ICAM-1 and TGF-β1 were markedly increased in high glucose-treated GMCs, leading to accumulation of fibronectin (FN), an important component of extracellular matrix (ECM), This effect was also effectively attenuated by Y27632 or dominant-negative RhoA mutant. In STZ-induced diabetic rats, treatment with ROCK inhibitor fasudil suppressed the RhoA/ROCK activation and NF-κB nuclear translocation, and significantly reduced the renal FN, ICAM-1 and TGF-β1 protein levels. Thus, the RhoA/ROCK pathway may regulate NF-κB to upregulate inflammatory genes and mediate the development of DN.
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Affiliation(s)
- Xi Xie
- Laboratory of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China
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Huang J, Huang K, Lan T, Xie X, Shen X, Liu P, Huang H. Curcumin ameliorates diabetic nephropathy by inhibiting the activation of the SphK1-S1P signaling pathway. Mol Cell Endocrinol 2013; 365:231-40. [PMID: 23127801 DOI: 10.1016/j.mce.2012.10.024] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 10/21/2012] [Accepted: 10/23/2012] [Indexed: 10/27/2022]
Abstract
Curcumin, a major polyphenol from the golden spice Curcuma longa commonly known as turmeric, has been recently discovered to have renoprotective effects on diabetic nephropathy (DN). However, the mechanisms underlying these effects remain unclear. We previously demonstrated that the sphingosine kinase 1-sphingosine 1-phosphate (SphK1-S1P) signaling pathway plays a pivotal role in the pathogenesis of DN. This study aims to investigate whether the renoprotective effects of curcumin on DN are associated with its inhibitory effects on the SphK1-S1P signaling pathway. Our results demonstrated that the expression and activity of SphK1 and the production of S1P were significantly down-regulated by curcumin in diabetic rat kidneys and glomerular mesangial cells (GMCs) exposed to high glucose (HG). Simultaneously, SphK1-S1P-mediated fibronectin (FN) and transforming growth factor-beta 1 (TGF-β1) overproduction were inhibited. In addition, curcumin dose dependently reduced SphK1 expression and activity in GMCs transfected with SphK(WT) and significantly suppressed the increase in SphK1-mediated FN levels. Furthermore, curcumin inhibited the DNA-binding activity of activator protein 1 (AP-1), and c-Jun small interference RNA (c-Jun-siRNA) reversed the HG-induced up-regulation of SphK1. These findings suggested that down-regulation of the SphK1-S1P pathway is probably a novel mechanism by which curcumin improves the progression of DN. Inhibiting AP-1 activation is one of the therapeutic targets of curcumin to modulate the SphK1-S1P signaling pathway, thereby preventing diabetic renal fibrosis.
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Affiliation(s)
- Juan Huang
- Laboratory of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China
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Lan T, Liu W, Xie X, Huang K, Peng J, Huang J, Shen X, Liu P, Yang H, Huang H. Berberine suppresses high glucose-induced TGF-β1 and fibronectin synthesis in mesangial cells through inhibition of sphingosine kinase 1/AP-1 pathway. Eur J Pharmacol 2012; 697:165-72. [DOI: 10.1016/j.ejphar.2012.10.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 09/25/2012] [Accepted: 10/09/2012] [Indexed: 11/16/2022]
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Xie X, Peng J, Huang K, Huang J, Shen X, Liu P, Huang H. Polydatin ameliorates experimental diabetes-induced fibronectin through inhibiting the activation of NF-κB signaling pathway in rat glomerular mesangial cells. Mol Cell Endocrinol 2012; 362:183-93. [PMID: 22732364 DOI: 10.1016/j.mce.2012.06.008] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2012] [Revised: 05/17/2012] [Accepted: 06/15/2012] [Indexed: 11/18/2022]
Abstract
A number of studies have recently demonstrated the involvement of nuclear factor-kappa B (NF-κB) activation and the subsequent coordinated inflammatory responses in the pathogenesis of diabetic nephropathy (DN). Polydatin has been shown to have the ability of anti-adhesive inflammation. However, the possible protective and beneficial effects of polydatin on DN via suppressing inflammatory damage and extracellular matrix (ECM) accumulation are not fully elucidated. We found that the polydatin could inhibit the induction and activity of NF-κB, and meanwhile ameliorating ECM accumulation in streptozotocin-diabetic rats. We aimed to investigate the effect of polydatin on fibronectin (FN) protein expression, and to elucidate its potential mechanism involving the NF-κB inflammatory signaling pathway in rat glomerular mesangial cells (GMCs) cultured under high glucose. The results revealed that polydatin significantly suppressed high glucose-induced FN production, inhibited NF-κB nuclear translocation, reduced the DNA-binding activity of NF-κB, as well as decreased the protein expression of ICAM-1 and TGF-β in GMCs. These findings suggested that polydatin significantly represses high glucose-induced FN expression in rat GMCs, which may be closely related to its inhibition of the NF-κB signaling pathway. Hence, we elucidated the potential mechanisms of the anti-inflammatory effects and ECM accumulation alleviation of polydatin in GMCs of DN in vitro.
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Affiliation(s)
- Xi Xie
- Laboratory of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
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Lan T, Liu W, Xie X, Xu S, Huang K, Peng J, Shen X, Liu P, Wang L, Xia P, Huang H. Sphingosine kinase-1 pathway mediates high glucose-induced fibronectin expression in glomerular mesangial cells. Mol Endocrinol 2011; 25:2094-105. [PMID: 21998146 DOI: 10.1210/me.2011-0095] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Diabetic nephropathy is characterized by accumulation of glomerular extracellular matrix proteins, such as fibronectin (FN). Here, we investigated whether sphingosine kinase (SphK)1 pathway is responsible for the elevated FN expression in diabetic nephropathy. The SphK1 pathway and FN expression were examined in streptozotocin-induced diabetic rat kidney and glomerular mesangial cells (GMC) exposed to high glucose (HG). FN up-regulation was concomitant with activation of the SphK1 pathway as reflected in an increase in the expression and activity of SphK1 and sphingosine 1-phosphate (S1P) production in both diabetic kidney and HG-treated GMC. Overexpression of wild-type SphK1 (SphK(WT)) significantly induced FN expression, whereas treatment with a SphK inhibitor, N,N-dimethylsphingosine, or transfection of SphK1 small interference RNA or dominant-negative SphK1 (SphK(G82D)) abolished HG-induced FN expression. Furthermore, addition of exogenous S1P significantly induced FN expression in GMC with an induction of activator protein 1 (AP-1) activity. Inhibition of AP-1 activity by curcumin attenuated the S1P-induced FN expression. Finally, by inhibiting SphK1 activity, both N,N-dimethylsphingosine and SphK(G82D) markedly attenuated the HG-induced AP-1 activity. Taken together, these results demonstrated that the SphK1 pathway plays a critical role in matrix accumulation in GMC under diabetic condition, suggesting that the SphK1 pathway could be a potential therapeutic target for diabetic nephropathy.
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Affiliation(s)
- Tian Lan
- Laboratory of Pharmacology and Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangdong Pharmaceutical University, Guangzhou 510006, China
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Liu G, Han F, Yang Y, Xie Y, Jiang H, Mao Y, Wang H, Wang M, Chen R, Yang J, Chen J. Evaluation of sphingolipid metabolism in renal cortex of rats with streptozotocin-induced diabetes and the effects of rapamycin. Nephrol Dial Transplant 2010; 26:1493-502. [PMID: 20961887 DOI: 10.1093/ndt/gfq633] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Abnormal lipid metabolism contributes to the pathogenesis of diabetes, but it is uncertain whether it plays a role in the development of diabetic nephropathy (DN). While rapamycin was shown to prevent DN development in streptozotocin (STZ)-induced diabetic rats in our previous studies, it is unknown if it intervenes with lipid metabolism. METHODS We divided the rats into four groups: normal control rats, rapamycin-treated normal rats, diabetic rats and rapamycin-treated DN rats. The apoptosis was evaluated by immunohistochemistry. The crude lipid and sphingolipid were extracted from rat renal cortex and analysed by matrix-assisted laser desorption ionization-time of flight mass spectrometry. The expression of the three key enzymes in sphingolipid metabolism including serine palmitoyltransferase, acid sphingomyelinase and sphingomyelin synthase was measured by western blot and immunohistochemistry in rat renal cortex. RESULTS The level of apoptosis was increased in diabetic rats, and rapamycin treatment reduced apoptosis. STZ treatment significantly increased formation of many sphingolipids species through elevated de novo synthesis. These changes were inhibited by treatment with rapamycin. CONCLUSIONS Accumulation of sphingolipids contributes to STZ-induced diabetes, and the therapeutic effect of rapamycin on diabetic nephropathy is partly through suppression of sphingolipid abnormality.
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Affiliation(s)
- GuangYi Liu
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
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Lan T, Shen X, Liu P, Liu W, Xu S, Xie X, Jiang Q, Li W, Huang H. RETRACTED: Berberine ameliorates renal injury in diabetic C57BL/6 mice: Involvement of suppression of SphK-S1P signaling pathway. Arch Biochem Biophys 2010; 502:112-20. [PMID: 20646989 DOI: 10.1016/j.abb.2010.07.012] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2010] [Revised: 07/03/2010] [Accepted: 07/14/2010] [Indexed: 12/27/2022]
Abstract
This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. This article shows significant data duplication and overlap with Liu, Weihua, et al., Effects of berberine on matrix accumulation and NF-kappa B signal pathway in alloxan-induced diabetic mice with renal injury. European Journal of Pharmacology. 2010 Jul 25;638(1-3):150-5 (https://doi.org/10.1016/j.ejphar.2010.04.033) without adequate referencing. Although there is a slight difference in the methodology section regarding alloxan-induced diabetes models in the two articles, there is a clear overlap between Table 2 of Lan, Tian, et al., (2010); and Tables 1 and 2 of Liu, Weihua, et al. (2010). The two manuscripts were submitted from the same laboratory in the same year.
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Affiliation(s)
- Tian Lan
- Sun Yat-sen University, Guangzhou, China
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63
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Chen SC, Guh JY, Hwang CC, Chiou SJ, Lin TD, Ko YM, Huang JS, Yang YL, Chuang LY. Advanced glycation end-products activate extracellular signal-regulated kinase via the oxidative stress-EGF receptor pathway in renal fibroblasts. J Cell Biochem 2010; 109:38-48. [PMID: 19885844 DOI: 10.1002/jcb.22376] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Advanced glycation end-products (AGEs), epidermal growth factor receptor (EGFR), reactive oxygen species (ROS), and extracellular signal-regulated kinases (ERK) are implicated in diabetic nephropathy (DN). Therefore, we asked if AGEs-induced ERK protein phosphorylation and mitogenesis are dependent on the receptor for AGEs (RAGE)-ROS-EGFR pathway in normal rat kidney interstitial fibroblast (NRK-49F) cells. We found that AGEs (100 microg/ml) activated EGFR and ERK1/2, which was attenuated by RAGE short-hairpin RNA (shRNA). AGEs also increased RAGE protein and intracellular ROS levels while RAGE shRNA and N-acetylcysteine (NAC) attenuated AGEs-induced intracellular ROS. Hydrogen peroxide (5-25 microM) increased RAGE protein level while activating both EGFR and ERK1/2. Low-dose hydrogen peroxide (5 microM) increased whereas high-dose hydrogen peroxide (100 microM) decreased mitogenesis at 3 days. AGEs-activated EGFR and ERK1/2 were attenuated by an anti-oxidant (NAC) and an EGFR inhibitor (Iressa). Moreover, AGEs-induced mitogenesis was attenuated by RAGE shRNA, NAC, Iressa, and an ERK1/2 inhibitor (PD98059). In conclusion, it was found that AGEs-induced mitogenesis is dependent on the RAGE-ROS-EGFR-ERK1/2 pathway whereas AGEs-activated ERK1/2 is dependent on the RAGE-ROS-EGFR pathway in NRK-49F cells.
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Affiliation(s)
- San-Cher Chen
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
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Gangoiti P, Camacho L, Arana L, Ouro A, Granado MH, Brizuela L, Casas J, Fabriás G, Abad JL, Delgado A, Gómez-Muñoz A. Control of metabolism and signaling of simple bioactive sphingolipids: Implications in disease. Prog Lipid Res 2010; 49:316-34. [PMID: 20193711 DOI: 10.1016/j.plipres.2010.02.004] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Revised: 02/18/2010] [Accepted: 02/22/2010] [Indexed: 01/05/2023]
Abstract
Simple bioactive sphingolipids include ceramide, sphingosine and their phosphorylated forms sphingosine 1-phosphate and ceramide 1-phosphate. These molecules are crucial regulators of cell functions. In particular, they play important roles in the regulation of angiogenesis, apoptosis, cell proliferation, differentiation, migration, and inflammation. Decoding the mechanisms by which these cellular functions are regulated requires detailed understanding of the signaling pathways that are implicated in these processes. Most importantly, the development of inhibitors of the enzymes involved in their metabolism may be crucial for establishing new therapeutic strategies for treatment of disease.
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Affiliation(s)
- Patricia Gangoiti
- Department of Biochemistry and Molecular Biology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Bilbao, Spain
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Arana L, Gangoiti P, Ouro A, Trueba M, Gómez-Muñoz A. Ceramide and ceramide 1-phosphate in health and disease. Lipids Health Dis 2010; 9:15. [PMID: 20137073 PMCID: PMC2828451 DOI: 10.1186/1476-511x-9-15] [Citation(s) in RCA: 146] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2009] [Accepted: 02/05/2010] [Indexed: 01/06/2023] Open
Abstract
Sphingolipids are essential components of cell membranes, and many of them regulate vital cell functions. In particular, ceramide plays crucial roles in cell signaling processes. Two major actions of ceramides are the promotion of cell cycle arrest and the induction of apoptosis. Phosphorylation of ceramide produces ceramide 1-phosphate (C1P), which has opposite effects to ceramide. C1P is mitogenic and has prosurvival properties. In addition, C1P is an important mediator of inflammatory responses, an action that takes place through stimulation of cytosolic phospholipase A2, and the subsequent release of arachidonic acid and prostaglandin formation. All of the former actions are thought to be mediated by intracellularly generated C1P. However, the recent observation that C1P stimulates macrophage chemotaxis implicates specific plasma membrane receptors that are coupled to Gi proteins. Hence, it can be concluded that C1P has dual actions in cells, as it can act as an intracellular second messenger to promote cell survival, or as an extracellular receptor agonist to stimulate cell migration.
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Affiliation(s)
- Lide Arana
- Department of Biochemistry and Molecular Biology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
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Fox TE, Kester M. Therapeutic strategies for diabetes and complications: a role for sphingolipids? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 688:206-16. [PMID: 20919656 DOI: 10.1007/978-1-4419-6741-1_14] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Diabetes is a debilitating chronic disease that has no cure and can only be managed by pharmaceutical or nutritional interventions. Worldwide, the incidence of diabetes and diabetic complications is dramatically increasing. This may reflect the incomplete knowledge base underlying the role of inflammatory or nutritional stresses to exacerbate diabetic complications. Despite the knowledge that hyperlipidemia is a cardinal feature of both Type 1 and 2 diabetes, the actual lipid species that contribute to complications such as diabetic nephropathy, retinopathy, neuropathy and cardiovascular disease have not been well defined, or have not elucidated new treatment strategies. Sphingolipids comprise only a fraction of total lipids but a body of evidence has now identified dysfunctional sphingolipid metabolism and/or generation of specific sphingolipid metabolites as contributors to diabetic complications. This review suggests that pharmacological therapies that target dysfunctional sphingolipid metabolism and/or signaling may prove beneficial in decreasing the chronic pathology of hyperglycemia and hyperlipidemia. Moreover, the review suggests that these treatment options may also prove beneficial to ameliorate or delay pancreatic beta cell failure.
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Affiliation(s)
- Todd E Fox
- Penn State College of Medicine, Department of Pharmacology, Hershey, Pennsylvania 17033, USA
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Zhu Q, Shan X, Miao H, Lu Y, Xu J, You N, Liu C, Liao DF, Jin J. Acute activation of acid ceramidase affects cytokine-induced cytotoxicity in rat islet beta-cells. FEBS Lett 2009; 583:2136-41. [PMID: 19497324 DOI: 10.1016/j.febslet.2009.05.047] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2009] [Revised: 05/21/2009] [Accepted: 05/26/2009] [Indexed: 10/20/2022]
Abstract
Ceramidase hydrolyzes ceramide and produces sphingosine as a substrate of sphingosine kinase (SPHK), which transforms sphingosine to sphingosine-1-phosphate. It has been reported that cytokines elicit SPHK activation in rat beta-cells. As a sphingosine provider, ceramidase should also be activated. In our previous work, we showed that the increase in mRNA and protein levels in cytokine-treated INS-1 rat beta-cells resulted in chronic activation of neutral ceramidase. Here we found that acid ceramidase (AC) is activated by cytokines at an early stage via tyrosine phosphorylation. In addition, basal AC activity was first detected in INS-1 cells and isolated rat islets, and cytokine-induced cell growth was significantly repressed when AC was pharmacologically inhibited.
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Affiliation(s)
- Qun Zhu
- Department of Endocrinology, The Second Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210011, PR China
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Wu BX, Zeidan YH, Hannun YA. Downregulation of neutral ceramidase by gemcitabine: Implications for cell cycle regulation. Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1791:730-9. [PMID: 19345744 DOI: 10.1016/j.bbalip.2009.03.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Revised: 02/24/2009] [Accepted: 03/17/2009] [Indexed: 01/01/2023]
Abstract
Gemcitabine (GMZ) is a chemotherapeutic agent with well established effects on cell growth arrest and apoptosis. In this study, we investigated the potential roles of bioactive sphingolipids in mediating the growth suppressing effects of GMZ on a polyoma middle T transformed murine endothelial cell line. After 12-hour GMZ (0.6 microM) treatment, cell growth was arrested at the G(0)/G(1) phase as detected by flow cytometric cell cycle analysis and MTT cell viability analysis, and this was accompanied by dephosphorylation of the retinoblastoma protein (Rb). Furthermore, GMZ treatment resulted in increased levels of specifically the very long chain ceramides as determined by mass spectrometry. Mechanistically, GMZ did not appear to affect the activities of many enzymes of ceramide metabolism; however, GMZ caused a selective reduction in the protein levels of neutral ceramidase (NCDase), as indicated by Western blot analysis, with a concomitant decrease in NCDase activity. The significance of NCDase loss on cell cycle regulation was investigated by specific knockdown of the enzyme using small interfering RNA (siRNA). Interestingly, NCDase siRNA transfection was sufficient to induce a cell cycle arrest at G(0)/G(1) and an increase in total ceramide levels, with significant elevation in very long chain ceramides (C(24:1) and C(24:0)). NCDase siRNA also induced Rb dephosphorylation. These data provide evidence for a novel mechanism of action for GMZ and highlight downregulation of NCDase as a critical step in GMZ-mediated ceramide elevation and cell cycle arrest.
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Affiliation(s)
- Bill X Wu
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, 29425, USA
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69
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Zhu Q, Jin JF, Shan XH, Liu CP, Mao XD, Xu KF, Liu C. Chronic activation of neutral ceramidase protects beta-cells against cytokine-induced apoptosis. Acta Pharmacol Sin 2008; 29:593-9. [PMID: 18430368 DOI: 10.1111/j.1745-7254.2008.00781.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
AIM To investigate the activity and expression of neutral ceramidase (N-CDase) in the insulin-secreting cell line INS-1 and its role in the cellular response to cytokines. METHODS HPLC, Western blotting, and quantitative real-time PCR were performed to detect the activity and expression of N-CDase in INS-1 cells treated with a cytokine mixture (5 ng/mL interleukin-1beta, 10 ng/mL TNF-alpha, and 50 ng/mL interferon-gamma). The expression and activity of N-CDase in the INS-1 cells were specifically inhibited using N-CDase-siRNA transfection. Annexin V-fluorescein- isothiocyanate/propidium iodide flow cytometry was used to assess apoptosis in the INS-1 cells. RESULTS The INS-1 cells exhibited some basal N-CDase activity, and cytokines induced a time-dependent delay in the activation of NCDase. As a result, the activation of N-CDase was first detectable at 8 h after stimulation. It peaked at 16 h and remained elevated at 24 h. Cytokines also upregulated the mRNA and protein expression of N-CDase in the INS-1 cells. Furthermore, when N-CDase activity was inhibited by RNA interference, cytokine-induced apoptosis in the INS-1 cells was markedly increased. CONCLUSION The N-CDase pathway is active in INS-1 cells, and the chronic activation of N-CDase is involved in the pathological response of beta-cells to cytokines, potentially providing protection against cytokine toxicity.
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Affiliation(s)
- Qun Zhu
- Department of Endocrinology, First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
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Advanced glycation end-product-inhibited cell proliferation and protein expression of beta-catenin and cyclin D1 are dependent on glycogen synthase kinase 3beta in LLC-PK1 cells. Arch Biochem Biophys 2008; 477:27-32. [PMID: 18474214 DOI: 10.1016/j.abb.2008.04.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Revised: 04/22/2008] [Accepted: 04/23/2008] [Indexed: 01/13/2023]
Abstract
Glycogen synthase kinase 3beta (GSK3beta) is increased by high glucose in mesangial cells. Thus, we studied the role of GSK3beta in advanced glycation end-product (AGE)-induced effects in the proximal tubule-like LLC-PK1 cells. We found that AGE (100 microg/ml) time-dependently (8-48 h) increased phospho-GSK3beta-Tyr216 (active GSK3beta) and time-dependently (4-24 h) decreased phospho-GSK3beta-Ser21/9 (inactive GSK3beta) protein expression. Meanwhile, AGE (100 microg/ml) activated GSK3beta kinase at 8-48 h. AGE (100 microg/ml) dose-dependently (75-100 microg/ml) decreased beta-catenin protein expression but AGE did not decrease beta-catenin protein expression until 48 h. SB216763 (a GSK3beta inhibitor) and GSK3beta shRNA attenuated AGE (100 microg/ml)-inhibited cell proliferation and protein expression of beta-catenin and cyclin D1 at 48 h. SB216763 also attenuated AGE-induced type IV collagen. We conclude that AGE activates GSK3beta in LLC-PK1 cells. AGE-inhibited beta-catenin and cyclin D1 protein expression are dependent on GSK3beta. Moreover, AGE-inhibited cell proliferation and AGE-induced type IV collagen protein expression are dependent on GSK3beta.
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71
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Alewijnse AE, Peters SLM. Sphingolipid signalling in the cardiovascular system: good, bad or both? Eur J Pharmacol 2008; 585:292-302. [PMID: 18420192 DOI: 10.1016/j.ejphar.2008.02.089] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2008] [Revised: 01/21/2008] [Accepted: 02/06/2008] [Indexed: 12/25/2022]
Abstract
Sphingolipids are biologically active lipids that play important roles in various cellular processes and the sphingomyelin metabolites ceramide, sphingosine and sphingosine-1-phosphate can act as signalling molecules in most cell types. With the recent development of the immunosuppressant drug FTY720 (Fingolimod) which after phosphorylation in vivo acts as a sphingosine-1-phosphate receptor agonist, research on the role of sphingolipids in the immune and other organ systems was triggered enormously. Since it was reported that FTY720 induced a modest, but significant transient decrease in heart rate in animals and humans, the question was raised which pharmacological properties of drugs targeting sphingolipid signalling will affect cardiovascular function in vivo. The answer to this question will most likely also indicate what type of drug could be used to treat cardiovascular disease. The latter is becoming increasingly important because of the increasing population carrying characteristics of the metabolic syndrome. This syndrome is, amongst others, characterized by obesity, hypertension, atherosclerosis and diabetes. As such, individuals with this syndrome are at increased risk of heart disease. Now numerous studies have investigated sphingolipid effects in the cardiovascular system, can we speculate whether certain sphingolipids under specific conditions are good, bad or maybe both? In this review we will give a brief overview of the pathophysiological role of sphingolipids in cardiovascular disease. In addition, we will try to answer how drugs that target sphingolipid signalling will potentially influence cardiovascular function and whether these drugs would be useful to treat cardiovascular disease.
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Affiliation(s)
- Astrid E Alewijnse
- Department of Pharmacology and Pharmacotherapy, Academic Medical Center, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
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Schmidt A, Kuhla B, Bigl K, Münch G, Arendt T. Cell cycle related signaling in neuro2a cells proceeds via the receptor for advanced glycation end products. J Neural Transm (Vienna) 2007; 114:1413-24. [PMID: 17564756 DOI: 10.1007/s00702-007-0770-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2007] [Accepted: 05/17/2007] [Indexed: 11/25/2022]
Abstract
Re-expression of cell cycle related genes such as cyclin-dependent kinases (cdk), cyclins, or cdk inhibitors in differentiated neurons in Alzheimer's disease (AD) is rooted in aberrant mitogenic signaling. Since microglia and astroglia proliferate in the vicinity of amyloid plaques, it is likely that plaque components or factors secreted from plaque-activated glia induce mitogenic signaling in neurons. Mitogenic compounds might be S100B, overexpressed by activated astrocytes, or advanced glycation end products (AGEs), a component of plaques. Both S100B and AGEs may interact with the multiligand receptor for AGEs (RAGE) and trigger for the activation of the p42/44 mitogen-activated protein kinase (p42/44 MAPK), whether they also count for cell cycle related signaling in neurons remains unresolved. By immunohistochemical staining, we confirmed that cyclin D(1) positive neurons are surrounded by AGE deposits, demonstrating the potential relevance in vivo. For exploring the mitogenic signal cascade, we used Neuro2a cells overexpressing human full-length RAGE (FL-RAGE) or the cytosolic deletion mutant (Delta-RAGE). In both cell lines, S100B and AGEs induced the production of reactive oxygen species but not in a RAGE-dependent manner. By contrast, in FL-RAGE cells but not in Delta-RAGE cells S100B and AGEs activate p42/44 MAPK, augment cyclin D(1)/cdk4 protein and RNA levels and the transition into the S-phase. Moreover, in FL-RAGE cells, decreased protein levels of the cdk inhibitor p16 were observed, and the p42/44 MAPK inhibitor UO126 prevented AGE and S100B stimulated cyclin D(1) expression and hindered cells to enter the S-phase. Our results demonstrate that S100B and AGE may serve as mitogenic sources for the stimulation of neurons to progress through the cell cycle whereby signaling proceeds via RAGE --> p42/44 MAPK --> cyclin D(1)/cdk4.
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Affiliation(s)
- A Schmidt
- Department of Neuroanatomy, Paul Flechsig Institute of Brain Research, University of Leipzig, Leipzig, Germany
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73
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Xu H, Shen J, Liu H, Shi Y, Li L, Wei M. Morroniside and loganin extracted from Cornus officinalis have protective effects on rat mesangial cell proliferation exposed to advanced glycation end products by preventing oxidative stress. Can J Physiol Pharmacol 2007; 84:1267-73. [PMID: 17487235 DOI: 10.1139/y06-075] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Advanced glycation end products (AGE) are involved in the alterations of renal mesangial cell (MCs) growth, a feature of early stages of diabetic nephropathy (DN). We postulate that morroniside and loganin, 2 components extracted from Cornus officinalis, may ameliorate the detrimental effects of AGE-induced MCs proliferation by preventing oxidative stress. Rat MCs cultured in AGE milieu were treated with morroniside and loganin. Results showed that morroniside and loganin inhibited AGE-induced MC proliferation as measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Fluorescence microscopy revealed that the morroniside and loganin improved the morphological changes of MCs. Flow cytometric analysis showed that morroniside and loganin inhibited the cell cycle of rat MCs. Furthermore, the level of reactive oxygen species was significantly reduced, and the activities of superoxide dismutase and glutathione peroxidase were markedly increased, whereas the level of malondialdehyde was not significantly reduced. These results suggest that morroniside and loganin regulate MC growth by preventing oxidative stress. Thus, this study provides a molecular basis for the use of morroniside and loganin in the early stages of DN.
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Affiliation(s)
- Huiqin Xu
- Department of Pharmacology, College of Pharmacy, Nanjing University of Traditional Chinese Medicine, 282 HanZhong Road, Nanjing 210029, China.
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Abstract
Diabetic nephropathy is a major cause of morbidity and mortality in diabetic patients. Two key mechanisms implicated in the development of diabetic nephropathy include advanced glycation and oxidative stress. Advanced glycation is the irreversible attachment of reducing sugars onto amino groups of proteins to form advanced glycation end products (AGEs). AGE modification of proteins may lead to alterations in normal function by inducing cross-linking of extracellular matrices. Intracellular formation of AGEs also can cause generalized cellular dysfunction. Furthermore, AGEs can mediate their effects via specific receptors, such as the receptor for AGE (RAGE), activating diverse signal transduction cascades and downstream pathways, including generation of reactive oxygen species (ROS). Oxidative stress occurs as a result of the imbalance between ROS production and antioxidant defenses. Sources of ROS include the mitochondria, auto-oxidation of glucose, and enzymatic pathways including nicotinamide adenine dinucleotide phosphate reduced (NAD[P]H) oxidase. Beyond the current treatments to treat diabetic complications such as the optimization of blood pressure and glycemic control, it is predicted that new therapies designed to target AGEs, including AGE formation inhibitors and cross-link breakers, as well as targeting ROS using novel highly specific antioxidants, will become part of the treatment regimen for diabetic renal disease.
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Affiliation(s)
- Adeline L Y Tan
- Albert Einstein Centre for Diabetes Complications, Baker Heart Research Institute, St. Kilda Road, Central Melbourne, Victoria 8008, Australia
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75
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Chen SC, Guh JY, Chen HC, Yang YL, Huang JS, Chuang LY. Advanced glycation end-product-induced mitogenesis is dependent on Janus kinase 2-induced heat shock protein 70 in normal rat kidney interstitial fibroblast cells. Transl Res 2007; 149:274-81. [PMID: 17466927 DOI: 10.1016/j.trsl.2006.08.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2006] [Revised: 08/16/2006] [Accepted: 08/19/2006] [Indexed: 01/22/2023]
Abstract
Kidney interstitial fibroblast proliferation is important in the pathogenesis of diabetic renal fibrosis. In this regard, advanced glycation end-product (AGE)-induced proliferation in normal rat kidney interstitial fibroblast (NRK-49F) cells is dependent on the Janus kinase 2 (JAK2) signal transducers and activators of transcription (STAT) pathway. Heat shock protein (Hsp) is a molecular target of JAK/STAT. Thus, the role of Hsp70 in AGE-induced mitogenesis in NRK-49F cells was studied. The AGE dose (100-200 microg/mL) and time (16-72 h) dependently increased Hsp70 protein expression. AGE-induced Hsp70 was attenuated by AG-490 (a JAK2 inhibitor) and N-acetylcysteine. AGE also increased tyrosine phosphorylation of Hsp70, cyclin E, and cyclin D1 (to a lesser extent) while increasing Hsp70 protein interactions with STAT1, STAT3, STAT5b, cyclin D1, and cyclin E. AGE-induced tyrosine phosphorylation of Hsp70 and cyclin E (but not cyclin D1) was attenuated by AG-490. AGE-induced mitogenesis, cyclin D1, and cyclin E were attenuated by Hsp70 antisense oligodeoxynucleotide and 2-aminopurine (an Hsp70 inhibitor). AGE-induced Hsp70 and mitogenesis were also attenuated by N-acetylcysteine. It was concluded that AGE-induced Hsp70 protein expression and tyrosine phosphorylation are dependent on JAK2 in NRK-49F cells. AGE increased protein-protein interactions among Hsp70, STAT1, STAT3, STAT5b, cyclin D1, and cyclin E. Moreover, AGE-induced mitogenesis is dependent on Hsp70 and oxidative stress.
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Affiliation(s)
- San-Cher Chen
- Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
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76
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Galadari S, Wu B, Mao C, Roddy P, El Bawab S, Hannun Y. Identification of a novel amidase motif in neutral ceramidase. Biochem J 2006; 393:687-95. [PMID: 16229686 PMCID: PMC1360721 DOI: 10.1042/bj20050682] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Neutral CDases (ceramidases) are newly identified enzymes with important roles in cell regulation, but little is known about their catalytic mechanisms. In the present study the full-length human neutral CDase was cloned and expressed in the yeast double-knockout strain Dypc1Dydc1, which lacks the yeast CDases YPC1p and YDC1p. Biochemical characterization of the human neutral CDase showed that the enzyme exhibited classical Michaelis-Menten kinetics, with an optimum activity at pH 7.5. Activity was enhanced by Na+ and Ca2+. Mg2+ and Mn2+ were somewhat stimulatory, but Zn2+, Cu2+ and Fe2+ inhibited the enzyme. Dithiothreitol and 2-mercaptoethanol dose-dependently inhibited neutral CDase. In order to identify which amino acids were involved in the catalytic action of neutral CDase, the purified enzyme was subjected to chemical modifications. It was observed that the serine residue modifier di-isopropyl fluorophosphate dose-dependently inhibited activity, implicating a serine residue in the catalytic action. From an alignment of the sequences of the neutral CDases from different species, all conserved serine residues were selected for site-directed mutagenesis. Of the six aligned serine residues that were mutated to alanine, only the S354A mutant lost its activity totally. Ser354 falls within a very highly conserved hexapeptide sequence GDVSPN, which itself was in the middle of a larger conserved sequence, namely NXGDVSPNXXGP/XXC. Moreover, mutations of Asp352 and Cys362 in the consensus sequence to alanine resulted in loss of activity of neutral CDase. Hence the present study identified a novel amidase sequence containing a critical serine residue that may function as a nucleophile in the hydrolytic attack on the amide bond present in ceramide.
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Affiliation(s)
- Sehamuddin Galadari
- *Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, U.S.A
| | - Bill X. Wu
- *Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, U.S.A
| | - Cungui Mao
- †Department of Medicine, Medical University of South Carolina, 173 Ashley Ave., Charleston, SC 29425, U.S.A
| | - Patrick Roddy
- *Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, U.S.A
| | - Samer El Bawab
- ‡Merck-Santé, CardioMetabolic Research, Chilly-Mazarin Research Center, 4 ave. F. Mitterrand, 91380 Chilly-Mazarin, France
| | - Yusuf A. Hannun
- *Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, U.S.A
- To whom correspondence should be addressed (email )
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Bohlender JM, Franke S, Stein G, Wolf G. Advanced glycation end products and the kidney. Am J Physiol Renal Physiol 2005; 289:F645-59. [PMID: 16159899 DOI: 10.1152/ajprenal.00398.2004] [Citation(s) in RCA: 272] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Advanced glycation end products (AGEs) are a heterogeneous group of protein and lipids to which sugar residues are covalently bound. AGE formation is increased in situations with hyperglycemia (e.g., diabetes mellitus) and is also stimulated by oxidative stress, for example in uremia. It appears that activation of the renin-angiotensin system may contribute to AGE formation through various mechanisms. Although AGEs could nonspecifically bind to basement membranes and modify their properties, they also induce specific cellular responses including the release of profibrogenic and proinflammatory cytokines by interacting with the receptor for AGE (RAGE). However, additional receptors could bind AGEs, adding to the complexity of this system. The kidney is both: culprit and target of AGEs. A decrease in renal function increases circulating AGE concentrations by reduced clearance as well as increased formation. On the other hand, AGEs are involved in the structural changes of progressive nephropathies such as glomerulosclerosis, interstitial fibrosis, and tubular atrophy. These effects are most prominent in diabetic nephropathy, but they also contribute to renal pathophysiology in other nondiabetic renal diseases. Interference with AGE formation has therapeutic potential for preventing the progression of chronic renal diseases, as shown from data of animal experiments and, more recently, the first clinical trials.
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Affiliation(s)
- Jürgen M Bohlender
- Klinik für Innere Medizin III, Universitätsklinik Jena, Erlanger Allee 101, Jena, Germany.
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78
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Masson E, Wiernsperger N, Lagarde M, Bawab S. Glucosamine induces cell-cycle arrest and hypertrophy of mesangial cells: implication of gangliosides. Biochem J 2005; 388:537-44. [PMID: 15654767 PMCID: PMC1138961 DOI: 10.1042/bj20041506] [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] [Indexed: 11/17/2022]
Abstract
Alterations in proliferation and hypertrophy of renal mesangial cells are typical features of diabetic nephropathy. The HP (hexosamine pathway) has been proposed as a biochemical hypothesis to explain microvascular alterations due to diabetic nephropathy; however, involvement of HP in the regulation of mesangial cell growth or hypertrophy has been poorly studied. Although gangliosides are known to regulate cell proliferation, their potential role in mesangial cell-growth perturbations has hardly been explored. In the present study, we investigated the effects of the HP activation, mimicked by GlcN (glucosamine) treatment, on mesangial cell growth and hypertrophy and the potential implication of gangliosides in these processes. Our results indicate that GlcN induced hypertrophy of mesangial cells, as measured by an increase in the protein/cell ratio, and it caused cell-cycle arrest by an increase in the expression of cyclin-dependent kinase inhibitor p21(Waf1/Cip1). Furthermore, GlcN treatment resulted in a massive increase in the levels of gangliosides G(M2) and G(M1). Treatment of cells with exogenous G(M2) and G(M1) reproduced the effects of 0.5 mM GlcN on p21(Waf1/Cip1) expression, cell-cycle arrest and hypertrophy, suggesting that gangliosides G(M2) and G(M1) are probably involved in mediating GlcN effects. These results document a new role of the HP in the regulation of mesangial cell growth and hypertrophy. They also suggest a potential new mechanism of action of the HP through modulation of ganglioside levels.
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Affiliation(s)
- Elodie Masson
- Diabetic Microangiopathy Research Unit, MERCK Santé/INSERM UMR 585, INSA Lyon (Institut National des Sciences Appliquées de Lyon), Louis Pasteur Bldg, 69621 Villeurbanne Cedex, France
| | - Nicolas Wiernsperger
- Diabetic Microangiopathy Research Unit, MERCK Santé/INSERM UMR 585, INSA Lyon (Institut National des Sciences Appliquées de Lyon), Louis Pasteur Bldg, 69621 Villeurbanne Cedex, France
| | - Michel Lagarde
- Diabetic Microangiopathy Research Unit, MERCK Santé/INSERM UMR 585, INSA Lyon (Institut National des Sciences Appliquées de Lyon), Louis Pasteur Bldg, 69621 Villeurbanne Cedex, France
| | - Samer El Bawab
- Diabetic Microangiopathy Research Unit, MERCK Santé/INSERM UMR 585, INSA Lyon (Institut National des Sciences Appliquées de Lyon), Louis Pasteur Bldg, 69621 Villeurbanne Cedex, France
- To whom correspondence should be addressed (email )
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Kume S, Kato S, Yamagishi SI, Inagaki Y, Ueda S, Arima N, Okawa T, Kojiro M, Nagata K. Advanced glycation end-products attenuate human mesenchymal stem cells and prevent cognate differentiation into adipose tissue, cartilage, and bone. J Bone Miner Res 2005; 20:1647-58. [PMID: 16059636 DOI: 10.1359/jbmr.050514] [Citation(s) in RCA: 200] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2004] [Revised: 05/11/2005] [Accepted: 05/20/2005] [Indexed: 01/03/2023]
Abstract
UNLABELLED The impact of AGEs on human MSCs was studied. AGEs inhibited the proliferation of MSCs, induced apoptosis, and prevented cognate differentiation into adipose tissue, cartilage, and bone, suggesting a deleterious effect of AGEs in the pathogenesis of musculoskeletal disorders in aged and diabetic patients. INTRODUCTION Advanced glycation end-products (AGEs) are accumulated on long-lived proteins of various tissues in advanced age and diabetes mellitus and have been implicated in chronic complication, including musculoskeletal disorders. Human mesenchymal stem cells (MSCs) potentially differentiate into mature musculoskeletal tissues during tissue repair, but the pathogenetic role of AGEs on MSCs is unclear. MATERIALS AND METHODS AGEs were prepared by incubating BSA with glucose, glyceraldehydes, or glycolaldehyde (designated as AGE-1, AGE-2, or AGE-3, respectively). Proliferation, apoptosis, and reactive oxygen species (ROS) generation were assayed in AGE-treated cells. The expression of the receptor for AGE (RAGE) was examined by immunohistochemistry and Western blotting. Involvement of RAGE-mediated signaling was examined using a neutralizing antiserum against RAGE. Differentiation into adipose tissue, cartilage, and bone were morphologically and biochemically monitored with specific markers for each. RESULTS AGE-2 and AGE-3, but not control nonglycated BSA and AGE-1, reduced the viable cell number and 5-bromo-2'deoxyuridine (BrdU) incorporation with increased intracellular ROS generation and the percentage of apoptotic cells. MSCs expressed RAGE and its induction was stimulated by AGE-2 and AGE-3. These AGEs inhibited adipogenic differentiation (assayed by oil red O staining, lipoprotein lipase production, and intracellular triglyceride content) and chondrogenic differentiation (assayed by safranin O staining and type II collagen production). On osteogenic differentiation, AGE-2 and AGE-3 increased alkaline phosphatase activity and intracellular calcium content; however, von Kossa staining revealed the loss of mineralization and mature bone nodule formation. The antiserum against RAGE partially prevented AGE-induced cellular events. CONCLUSION AGE-2 and AGE-3 may lead to the in vivo loss of MSC mass and the delay of tissue repair by inhibiting the maturation of MSC-derived cells. The AGE-RAGE interaction may be involved in the deleterious effect of AGEs on MSCs.
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Affiliation(s)
- Shinichiro Kume
- Department of Orthopaedic Surgery, Kurume University School of Medicine, Kurume, Japan
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80
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Geoffroy K, Troncy L, Wiernsperger N, Lagarde M, El Bawab S. Glomerular proliferation during early stages of diabetic nephropathy is associated with local increase of sphingosine-1-phosphate levels. FEBS Lett 2005; 579:1249-54. [PMID: 15710421 DOI: 10.1016/j.febslet.2004.12.094] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2004] [Revised: 11/17/2004] [Accepted: 12/20/2004] [Indexed: 12/26/2022]
Abstract
In this study, the effects of short-term diabetes (4 days) on rat renal glomerular cells proliferation and the potential involvement of sphingolipids in this process were investigated. Immunohistochemical analysis showed that streptozotocin (STZ)-induced diabetes promoted increased intra-glomerular hyperplasia, particularly marked for mesangial cells. This was associated with a concomitant increase in neutral ceramidase and sphingosine-kinase activities and the accumulation of the pro-proliferative sphingolipid sphingosine-1-phosphate, in glomeruli isolated from kidney cortex of STZ-treated rats. These results suggest a possible involvement of sphingolipid metabolites in the glomerular proliferative response during the early stages of diabetic nephropathy.
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Affiliation(s)
- Karen Geoffroy
- Diabetic Microangiopathy Research Unit, MERCK Santé, INSERM UMR 585/INSA-Lyon, 69621 Villeurbanne, France
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Masson E, Troncy L, Ruggiero D, Wiernsperger N, Lagarde M, El Bawab S. a-Series gangliosides mediate the effects of advanced glycation end products on pericyte and mesangial cell proliferation: a common mediator for retinal and renal microangiopathy? Diabetes 2005; 54:220-7. [PMID: 15616032 DOI: 10.2337/diabetes.54.1.220] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Advanced glycation end products (AGEs) are involved in the development of microvascular complications, including alterations of retinal pericyte and renal mesangial cell growth occurring during diabetic retinopathy and diabetic nephropathy, respectively. Because gangliosides are implicated in the regulation of cell proliferation, we hypothesized that AGEs could exert cellular effects in part by modulating ganglioside levels. Results of the present study indicate that AGEs caused an inhibition of both bovine retinal pericyte (BRP) and rat renal mesangial cell (RMC) proliferation, associated with an increase of a-series gangliosides consecutive to GM3 synthase activity increase and GD3 synthase activity inhibition. Similar modifications were also found in the renal cortex of diabetic db/db mice compared with controls. Treatment of BRP and RMC with exogenous a-series gangliosides decreased proliferation and blockade of a-series gangliosides with specific antibodies partially protecting the two cell types from the AGE-induced proliferation decrease. Further, inhibition of GM3 synthase using specific SiRNA partially reversed the AGE effects on mesangial cell proliferation. These results suggest that a-series gangliosides are mediators of the adverse AGE effects on BRP and RMC proliferation. They also raise the hypothesis of common mechanisms involved in the development of diabetic retinopathy and diabetic nephropathy.
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Affiliation(s)
- Elodie Masson
- Diabetic Microangiopathy Research Unit, MERCK Santé-INSERM U585, INSA-Lyon, Louis Pasteur Bldg., 69621 Villeurbanne Cedex, France
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