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Simões E Silva AC, Oliveira EA, Cheung WW, Mak RH. Redox Signaling in Chronic Kidney Disease-Associated Cachexia. Antioxidants (Basel) 2023; 12:antiox12040945. [PMID: 37107320 PMCID: PMC10136196 DOI: 10.3390/antiox12040945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 04/14/2023] [Accepted: 04/14/2023] [Indexed: 04/29/2023] Open
Abstract
Redox signaling alterations contribute to chronic kidney disease (CKD)-associated cachexia. This review aims to summarize studies about redox pathophysiology in CKD-associated cachexia and muscle wasting and to discuss potential therapeutic approaches based on antioxidant and anti-inflammatory molecules to restore redox homeostasis. Enzymatic and non-enzymatic systems of antioxidant molecules have been studied in experimental models of kidney diseases and patients with CKD. Oxidative stress is increased by several factors present in CKD, including uremic toxins, inflammation, and metabolic and hormone alterations, leading to muscle wasting. Rehabilitative nutritional and physical exercises have shown beneficial effects for CKD-associated cachexia. Anti-inflammatory molecules have also been tested in experimental models of CKD. The importance of oxidative stress has been shown by experimental studies in which antioxidant therapies ameliorated CKD and its associated complications in the 5/6 nephrectomy model. Treatment of CKD-associated cachexia is a challenge and further studies are necessary to investigate potential therapies involving antioxidant therapy.
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Affiliation(s)
- Ana Cristina Simões E Silva
- Department of Pediatrics, Division of Pediatric Nephrology, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte 30130-100, MG, Brazil
| | - Eduardo A Oliveira
- Department of Pediatrics, Division of Pediatric Nephrology, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte 30130-100, MG, Brazil
| | - Wai W Cheung
- Department of Pediatrics, Rady Children's Hospital San Diego, University of California San Diego, La Jolla, CA 92093, USA
| | - Robert H Mak
- Department of Pediatrics, Rady Children's Hospital San Diego, University of California San Diego, La Jolla, CA 92093, USA
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Haffner D, Grund A, Leifheit-Nestler M. Renal effects of growth hormone in health and in kidney disease. Pediatr Nephrol 2021; 36:2511-2530. [PMID: 34143299 PMCID: PMC8260426 DOI: 10.1007/s00467-021-05097-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 04/27/2021] [Indexed: 12/29/2022]
Abstract
Growth hormone (GH) and its mediator insulin-like growth factor-1 (IGF-1) have manifold effects on the kidneys. GH and IGF receptors are abundantly expressed in the kidney, including the glomerular and tubular cells. GH can act either directly on the kidneys or via circulating or paracrine-synthesized IGF-1. The GH/IGF-1 system regulates glomerular hemodynamics, renal gluconeogenesis, tubular sodium and water, phosphate, and calcium handling, as well as renal synthesis of 1,25 (OH)2 vitamin D3 and the antiaging hormone Klotho. The latter also acts as a coreceptor of the phosphaturic hormone fibroblast-growth factor 23 in the proximal tubule. Recombinant human GH (rhGH) is widely used in the treatment of short stature in children, including those with chronic kidney disease (CKD). Animal studies and observations in acromegalic patients demonstrate that GH-excess can have deleterious effects on kidney health, including glomerular hyperfiltration, renal hypertrophy, and glomerulosclerosis. In addition, elevated GH in patients with poorly controlled type 1 diabetes mellitus was thought to induce podocyte injury and thereby contribute to the development of diabetic nephropathy. This manuscript gives an overview of the physiological actions of GH/IGF-1 on the kidneys and the multiple alterations of the GH/IGF-1 system and its consequences in patients with acromegaly, CKD, nephrotic syndrome, and type 1 diabetes mellitus. Finally, the impact of short- and long-term treatment with rhGH/rhIGF-1 on kidney function in patients with kidney diseases will be discussed.
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Affiliation(s)
- Dieter Haffner
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Pediatric Research Center, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
- Pediatric Research Center, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
| | - Andrea Grund
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Pediatric Research Center, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
- Pediatric Research Center, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Maren Leifheit-Nestler
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Pediatric Research Center, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
- Pediatric Research Center, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
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Tao M, Zheng D, Liang X, Wu D, Hu K, Jin J, He Q. Tripterygium glycoside suppresses epithelial‑to‑mesenchymal transition of diabetic kidney disease podocytes by targeting autophagy through the mTOR/Twist1 pathway. Mol Med Rep 2021; 24:592. [PMID: 34165172 PMCID: PMC8222798 DOI: 10.3892/mmr.2021.12231] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 03/25/2021] [Indexed: 12/23/2022] Open
Abstract
Tripterygium glycoside (TG) is a traditional Chinese medicine extract with immunosuppressive, anti-inflammatory and anti-renal fibrosis effects. Epithelial-mesenchymal transition (EMT) and cell apoptosis are considered to be the major cause of podocyte injury in diabetic kidney disease (DKD). However, it remains unknown as to whether TG is able to alleviate podocyte injury to prevent DKD progression. Therefore, the present study aimed to clarify the podocyte protective effects of TG on DKD. TG, Twist1 small interfering RNA (siRNA) and Twist1 overexpression vector were added to DKD mouse serum-induced podocytes in vitro. Autophagic and EMT activities were evaluated by immunofluorescence staining and western blot analysis. Apoptotic activity was evaluated by Annexin V-FITC/PI flow cytometric analysis. The results revealed that after treatment with DKD mouse serum, autophagy was decreased, whereas EMT and apoptotic rate were increased, in podocytes. In addition, Twist1 expression was increased in DKD-induced podocytes. Furthermore, following Twist1-small interfering RNA transfection, the DKD-induced podocyte EMT and apoptotic rate were markedly reduced, indicating that Twist1 may be a promising therapeutic target for DKD. The present results also revealed that overexpression of Twist1 increased podocyte apoptosis, although this was decreased after TG treatment, indicating that TG may exhibit a protective effect on podocytes by inhibiting the Twist1 signaling pathway. After the addition of 3-benzyl-5-((2-nitrophenoxy) methyl)-dihydrofuran-2(3H)-one, an activator of mTORC1, the effects of TG on podocyte EMT, apoptosis and the autophagy were reversed. These findings indicated that TG may alleviate EMT and apoptosis by upregulating autophagy through the mTOR/Twist1 signaling pathway in DKD.
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Affiliation(s)
- Mei Tao
- Department of Nephrology, The Affiliated Hospital of Hangzhou Normal University, Hangzhou, Zhejiang 310015, P.R. China
| | - Danna Zheng
- Department of Nephrology, Zhejiang Provincial People's Hospital and Affiliated People's Hospital, Hangzhou Medical College, Hangzhou, Zhejiang 310014, P.R. China
| | - Xudong Liang
- Department of Nephrology, Zhejiang Provincial People's Hospital and Affiliated People's Hospital, Hangzhou Medical College, Hangzhou, Zhejiang 310014, P.R. China
| | - Diandian Wu
- Department of Nephrology, Zhejiang Provincial People's Hospital and Affiliated People's Hospital, Hangzhou Medical College, Hangzhou, Zhejiang 310014, P.R. China
| | - Kang Hu
- Department of Nephrology, Zhejiang Provincial People's Hospital and Affiliated People's Hospital, Hangzhou Medical College, Hangzhou, Zhejiang 310014, P.R. China
| | - Juan Jin
- Department of Nephrology, Zhejiang Provincial People's Hospital and Affiliated People's Hospital, Hangzhou Medical College, Hangzhou, Zhejiang 310014, P.R. China
| | - Qiang He
- Department of Nephrology, Zhejiang Provincial People's Hospital and Affiliated People's Hospital, Hangzhou Medical College, Hangzhou, Zhejiang 310014, P.R. China
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4
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Li G, Huang D, Hong J, Bhat OM, Yuan X, Li PL. Control of lysosomal TRPML1 channel activity and exosome release by acid ceramidase in mouse podocytes. Am J Physiol Cell Physiol 2019; 317:C481-C491. [PMID: 31268777 PMCID: PMC6766620 DOI: 10.1152/ajpcell.00150.2019] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/18/2019] [Accepted: 06/19/2019] [Indexed: 02/07/2023]
Abstract
The transient receptor potential mucolipin 1 (TRPML1) channel has been reported to mediate lysosomal Ca2+ release that is involved in Ca2+-dependent lysosome trafficking and autophagic flux. However, this regulatory mechanism of lysosomal TRPML1 channel activity in podocytes remains poorly understood. In the present study, we tested whether the TRPML1 channel in podocytes mediates lysosome trafficking, which is essential for multivesicular body (MVB) degradation by lysosomes. We first demonstrated the abundant expression of TRPML1 channel in podocytes. By GCaMP3 Ca2+ imaging, we characterized the lysosomal specificity of TRPML1 channel-mediated Ca2+ release in podocytes. Given the important role of acid ceramidase (AC) in lysosome function and podocyte injury, we tested whether AC regulates this TRPML1 channel-mediated Ca2+ release and consequent lysosome-dependent MVB degradation in podocytes. Pharmacologically, it was found that TRPML1 channel activity was remarkably attenuated by the AC inhibitor carmofur. Sphingosine, as an AC product, was demonstrated to induce TRPML1-mediated Ca2+ release, which was inhibited by a TRPML1 blocker, verapamil. Using a Port-a-Patch planar patch-clamp system, we found that AC-associated sphingolipids, sphingomyelin, ceramide, and sphingosine had different effects on TRPML1 channel activity in podocytes. Functionally, the inhibition of AC or blockade of TRPML1 channels was found to suppress the interaction of lysosomes and MVBs, leading to increased exosome release from podocytes. These results suggest that AC is critical for TRPML1 channel-mediated Ca2+ release, which controls lysosome-MVB interaction and exosome release in podocytes.
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Affiliation(s)
- Guangbi Li
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia
| | - Dandan Huang
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia
| | - Jinni Hong
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia
| | - Owais M Bhat
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia
| | - Xinxu Yuan
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia
| | - Pin-Lan Li
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia
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He J, Sun Y, Jia Y, Geng X, Chen R, Zhou H, Yang B. Ganoderma triterpenes Protect Against Hyperhomocysteinemia Induced Endothelial-Mesenchymal Transition via TGF-β Signaling Inhibition. Front Physiol 2019; 10:192. [PMID: 30890956 PMCID: PMC6412081 DOI: 10.3389/fphys.2019.00192] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 02/15/2019] [Indexed: 12/15/2022] Open
Abstract
Endothelial dysfunction is one of the most important pathological status in hyperhomocysteinemia (HHcy) related cardiovascular diseases. Whereas, the underlying mechanisms have not been fully elucidated yet, concomitant with the absence of effective treatment. The purpose of this study was to explore the main mechanisms involved in HHcy-induced endothelial injury and identify the protective effect of Ganoderma triterpenes (GT). Bovine aortic endothelial cells (BAECs) were applied as in vitro experimental model. The small molecular inhibitors were used to explore the signalings involved in HHcy-induced endothelial injury. The experimental results provided initial evidence that HHcy led to endothelial-mesenchymal transition (EndMT). Meanwhile, TGF-β/Smad, PI3K/AKT and MAPK pathways were activated in this process, which was demonstrated by pretreatment with TGF-β RI kinase inhibitor VI SB431542, PI3K inhibitor LY294002, p38 inhibitor SB203580, and ERK inhibitor PD98059. Furthermore, it was found that GT restrained the process of HHcy-induced EndMT via reducing oxidative stress and suppressing fore mentioned pathways with further inhibiting the activity of Snail. These results implicate that there is an untapped potential for GT as a novel therapeutic candidate for HHcy-induced EndMT through alleviating oxidative stress and canonical TGF-β/Smad and non-Smad dependent signaling pathways.
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Affiliation(s)
- Jinzhao He
- Key Laboratory of Molecular Cardiovascular Sciences, State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Yi Sun
- Key Laboratory of Molecular Cardiovascular Sciences, State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Yingli Jia
- Key Laboratory of Molecular Cardiovascular Sciences, State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Xiaoqiang Geng
- Key Laboratory of Molecular Cardiovascular Sciences, State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Ruoyun Chen
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Chinese Academy of Medical Sciences, Institute of Materia Medica, Peking Union Medical College, Beijing, China
| | - Hong Zhou
- Key Laboratory of Molecular Cardiovascular Sciences, State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Baoxue Yang
- Key Laboratory of Molecular Cardiovascular Sciences, State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
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6
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Li G, Zhang Q, Hong J, Ritter JK, Li PL. Inhibition of pannexin-1 channel activity by adiponectin in podocytes: Role of acid ceramidase activation. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1863:1246-1256. [PMID: 30077007 DOI: 10.1016/j.bbalip.2018.07.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 07/25/2018] [Accepted: 07/29/2018] [Indexed: 12/19/2022]
Abstract
The pannexin-1 (Panx1) channel has been reported to mediate the release of ATP that is involved in local tissue inflammation, obesity, and many chronic degenerative diseases. It remains unknown whether Panx1 is present in podocytes and whether this channel in podocytes mediates ATP release leading to glomerular inflammation or fibrosis. To answer these questions, we first characterized the expression of Panx channels in podocytes. Among the three known pannexins, Panx1 was the most enriched in podocytes, either cultured or native in mouse glomeruli. Using a Port-a-Patch planar patch-clamp system, we recorded a large voltage-gated outward current through podocyte membrane under the Cs+in/Na+out gradient. Substitution of gluconate or aspartate for chloride in the bath solution blocked voltage-gated outward currents and shifted the reversal potential of Panx1 currents to the right, indicating the anion permeability of this channel. Pharmacologically, the recorded voltage-gated outward currents were substantially attenuated by specific Panx1 channel inhibitors. Given the anti-inflammatory and intracellular ATP restorative effects of adiponectin, we tested whether this adipokine inhibits Panx1 channel activity to block ATP release. Adiponectin blocked Panx1 channel activity in podocytes. Mechanistically, inhibition of acid ceramidase (AC) remarkably enhanced Panx1 channel activity under control conditions and prevented the inhibition of Panx1 channel by adiponectin. Correspondingly, intracellular addition of AC products, sphingosine or sphingosine-1-phosphate (S1P), blocked Panx1 channel activity, while elevation of intracellular ceramide had no effect on Panx1 channel activity. These results suggest that adiponectin inhibits Panx1 channel activity in podocytes through activation of AC and associated elevation of intracellular S1P.
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Affiliation(s)
- Guangbi Li
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, School of Medicine, Richmond, VA 23298, United States of America
| | - Qinghua Zhang
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, School of Medicine, Richmond, VA 23298, United States of America
| | - Jinni Hong
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, School of Medicine, Richmond, VA 23298, United States of America
| | - Joseph K Ritter
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, School of Medicine, Richmond, VA 23298, United States of America
| | - Pin-Lan Li
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, School of Medicine, Richmond, VA 23298, United States of America.
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7
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Brittain AL, Basu R, Qian Y, Kopchick JJ. Growth Hormone and the Epithelial-to-Mesenchymal Transition. J Clin Endocrinol Metab 2017; 102:3662-3673. [PMID: 28938477 DOI: 10.1210/jc.2017-01000] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 07/31/2017] [Indexed: 02/07/2023]
Abstract
CONTEXT Previous studies have implicated growth hormone (GH) in the progression of several cancers, including breast, colorectal, and pancreatic. A mechanism by which GH may play this role in cancer is through the induction of the epithelial-to-mesenchymal transition (EMT). During the EMT process, epithelial cells lose their defining phenotypes, causing loss of cellular adhesion and increased cell migration. This review aims to carefully summarize the previous two decades of research that points to GH as an initiator of EMT, in both cancerous and noncancerous tissues. EVIDENCE ACQUISITION Sources were collected using PubMed and Google Scholar search engines by using specific GH- and/or EMT-related terms. Identified manuscripts were selected for further analysis based on presentation of GH-induced molecular markers of the EMT process in vivo or in vitro. EVIDENCE SYNTHESIS Cellular mechanisms involved in GH-induced EMT are the focus of this review, both in cancerous and noncancerous epithelial cells. CONCLUSIONS Our findings suggest that a myriad of molecular mechanisms are induced by GH that cause EMT and may point to potential therapeutic use of GH antagonists or any downregulator of GH action in EMT-related disease.
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Affiliation(s)
- Alison L Brittain
- Edison Biotechnology Institute, Ohio University, Athens, Ohio 45701
- Ohio University Heritage College of Osteopathic Medicine, Athens, Ohio 45701
| | - Reetobrata Basu
- Edison Biotechnology Institute, Ohio University, Athens, Ohio 45701
| | - Yanrong Qian
- Edison Biotechnology Institute, Ohio University, Athens, Ohio 45701
| | - John J Kopchick
- Edison Biotechnology Institute, Ohio University, Athens, Ohio 45701
- Ohio University Heritage College of Osteopathic Medicine, Athens, Ohio 45701
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Li TX, Mao JH, Huang L, Fu HD, Chen SH, Liu AM, Liang YQ. Beneficial effects of Huaiqihuang on hyperglycemia-induced MPC5 podocyte dysfunction through the suppression of mitochondrial dysfunction and endoplasmic reticulum stress. Mol Med Rep 2017. [PMID: 28627684 DOI: 10.3892/mmr.2017.6753] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The present study was performed to investigate the effect of Huaiqihuang (HQH) on hyperglycemia (HG)-induced mitochondrial dysfunction and endoplasmic reticulum (ER) stress in MPC5 podocytes. The effects of HQH and HG on cell viability were assessed using an MTT assay. mRNA and protein expression levels were evaluated using reverse transcription-quantitative polymerase chain reaction and western blot analysis, respectively. Cell apoptosis was assessed using terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling, whereas reactive oxygen species production and alterations in mitochondrial membrane potential were assessed using flow cytometry. DNA damage was evaluated using a comet assay. The results demonstrated that treatment of podocytes with HQH markedly suppressed the HG‑induced generation of reactive oxygen species. HQH also significantly improved mitochondrial membrane potential in podocytes exposed to HG. When the podocytes were treated with HG, Ca2+ levels were significantly increased, compared with those in the control group, whereas treatment of the podocytes with HQH significantly reversed the HG‑induced upregulation of Ca2+ secretion. Treatment of the podocytes with HQH significantly reversed the HG‑induced upregulation of glucose‑related protein 78 (GRP78) and C/EBP‑homologous protein, which were used as indicators of ER stress. Furthermore, GRP78 loss‑of‑function attenuated HG‑induced podocyte dysfunction, including cell apoptosis and DNA damage. In conclusion, beneficial effects of HQH on HG‑induced MPC5 podocyte dysfunction were observed, and occurred through the suppression of mitochondrial dysfunction and ER stress.
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Affiliation(s)
- Ting-Xia Li
- Department of Nephrology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang 310003, P.R. China
| | - Jian-Hua Mao
- Department of Nephrology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang 310003, P.R. China
| | - Lei Huang
- Department of Nephrology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang 310003, P.R. China
| | - Hai-Dong Fu
- Department of Nephrology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang 310003, P.R. China
| | - Shuo-Hui Chen
- Department of Nephrology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang 310003, P.R. China
| | - Ai-Min Liu
- Department of Nephrology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang 310003, P.R. China
| | - Yu-Qin Liang
- Department of Nephrology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang 310003, P.R. China
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Role of NADPH Oxidase in Metabolic Disease-Related Renal Injury: An Update. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:7813072. [PMID: 27597884 PMCID: PMC5002489 DOI: 10.1155/2016/7813072] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 07/17/2016] [Indexed: 01/09/2023]
Abstract
Metabolic syndrome has been linked to an increased risk of chronic kidney disease. The underlying pathogenesis of metabolic disease-related renal injury remains obscure. Accumulating evidence has shown that NADPH oxidase is a major source of intrarenal oxidative stress and is upregulated by metabolic factors leading to overproduction of ROS in podocytes, endothelial cells, and mesangial cells in glomeruli, which is closely associated with the initiation and progression of glomerular diseases. This review focuses on the role of NADPH oxidase-induced oxidative stress in the pathogenesis of metabolic disease-related renal injury. Understanding of the mechanism may help find potential therapeutic strategies.
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10
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Datta N, Lindfors S, Miura N, Saleem MA, Lehtonen S. Overexpression of transcription factor FOXC2 in cultured human podocytes upregulates injury markers and increases motility. Exp Cell Res 2015; 340:32-42. [PMID: 26524507 DOI: 10.1016/j.yexcr.2015.10.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 10/09/2015] [Accepted: 10/29/2015] [Indexed: 01/23/2023]
Abstract
Obesity and diabetes-related kidney diseases associate with renal failure and cardiovascular morbidity, and represent a major health issue worldwide. However, the molecular mechanisms leading to their development remain poorly understood. We observed increased expression of transcription factor FoxC2 in the podocytes of obese Zucker rats that are insulin resistant and albuminuric. We also found that depletion of adiponectin, an adipocyte-derived hormone whose secretion is decreased in obesity, upregulated FOXC2 in differentiated human podocytes in vitro. Overexpression of FOXC2 in cultured human podocytes led to increased nuclear expression of FOXC2 associated with a change of cellular morphology. This was accompanied by upregulation of vimentin, a key mesenchymal marker, and active beta-catenin, associated with podocyte injury. We also observed re-organization of the actin cytoskeleton, disrupted localization of the tight junction protein ZO-1, and increased motility of podocytes overexpressing FOXC2. These data indicate that the expression of FOXC2 in podocytes needs to be tightly regulated, and that its overexpression induces a chain of cellular events leading to podocyte dysfunction. These changes may lead to podocyte detachment and depletion ultimately contributing to albuminuria. We also suggest a novel molecular mechanism linking obesity-induced decrease in adiponectin to podocyte dysfunction via upregulation of FOXC2.
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Affiliation(s)
- Neeta Datta
- Department of Pathology, University of Helsinki, 00290 Helsinki, Finland
| | - Sonja Lindfors
- Department of Pathology, University of Helsinki, 00290 Helsinki, Finland
| | - Naoyuki Miura
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan
| | - Moin A Saleem
- Academic and Children's Renal Unit, Dorothy Hodgkin Building, Bristol BS1, United Kingdom
| | - Sanna Lehtonen
- Department of Pathology, University of Helsinki, 00290 Helsinki, Finland.
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11
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The wnt/β-catenin signaling pathway participates in rhein ameliorating kidney injury in DN mice. Mol Cell Biochem 2015; 411:73-82. [DOI: 10.1007/s11010-015-2569-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 09/03/2015] [Indexed: 10/23/2022]
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12
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Li C, Siragy HM. (Pro)renin receptor regulates autophagy and apoptosis in podocytes exposed to high glucose. Am J Physiol Endocrinol Metab 2015; 309:E302-10. [PMID: 26081285 PMCID: PMC4525115 DOI: 10.1152/ajpendo.00603.2014] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 06/05/2015] [Indexed: 12/20/2022]
Abstract
High glucose reduces autophagy and enhances apoptosis of podocytes. Previously, we reported that high glucose induced podocyte injury through upregulation of the (pro)renin receptor (PRR). We hypothesized that increasing PRR reduces autophagy and increases apoptosis of mouse podocytes exposed to high glucose via activation of the PI3K/Akt/mTOR signaling pathway. Mouse podocytes were cultured in normal (5 mmol/l) or high (25 mmol/l) d-glucose for 48 h. High glucose significantly increased mRNA and protein levels of PRR, phosphorylation of PI3K/Akt/mTOR, and p62. In contrast, high glucose decreased activation of UNC-51-like kinase-1 (ULK1) by phosphorylating Ser⁷⁵⁷ and protein levels of microtubule-associated protein-1 light chain 3B (LC3B)-II and Lamp-2. Bafilomycin A1 increased LC3BII and p62 accumulation in high-glucose-treated cells. High glucose reduced the autophagic flux. Confocal microscopy studies showed significant reduction in the protein level of LC3B in response to high glucose. Cyto-ID autophagy staining showed a significant decrease in autophagosome formation with high glucose. In the absence of PRR, activation of Akt with sc-79 or mTOR with MHY-1485 increased p62 accumulation. Caspase-3/7 activity and apoptosis monitored by TUNEL assay were significantly increased in podocytes treated with high glucose. PRR siRNA significantly reversed the effects of high glucose. Based on these data, we conclude that high glucose decreases autophagy and increases apoptosis in mouse podocytes through the PRR/PI3K/Akt/mTOR signaling pathway.
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Affiliation(s)
- Caixia Li
- Division of Endocrinology and Metabolism, University of Virginia Health System, Charlottesville, Virginia
| | - Helmy M Siragy
- Division of Endocrinology and Metabolism, University of Virginia Health System, Charlottesville, Virginia
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13
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Liu XD, Zhang LY, Zhu TC, Zhang RF, Wang SL, Bao Y. Overexpression of miR-34c inhibits high glucose-induced apoptosis in podocytes by targeting Notch signaling pathways. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2015; 8:4525-4534. [PMID: 26191142 PMCID: PMC4503014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 04/21/2015] [Indexed: 06/04/2023]
Abstract
Recent findings have shown that microRNAs play critical roles in the pathogenesis of diabetic nephropathy. miR-34c has been found to inhibit fibrosis and the epithelial-mesenchymal transition of kidney cells. However, the role of miR-34c in diabetic nephropathy has not been well studied. The current study was designed to investigate the role and potential underlying mechanism of miR-34c in regulating diabetic nephropathy. After treating podocytes with high glucose (HG) in vitro, we found that miR-34c was downregulated and that overexpression of miR-34c inhibited HG-induced podocyte apoptosis. The direct interaction between miR-34c and the 3'-untranslated region (UTR) of Notch1 and Jagged1 was validated by dual-luciferase reporter assay. Moreover, Notch1 and Jagged1 as putative targets of miR-34c were downregulated by miR-34c overexpression in HG-treated podocytes. Overexpression of miR-34c inhibited HG-induced Notch signaling pathway activation, as indicated by decreased expression of the Notch intracellular domain (NICD) and downstream genes including Hes1 and Hey1. Furthermore, miR-34c overexpression increased the expression of the anti-apoptotic gene Bcl-2, and decreased the expression of the pro-apoptotic protein Bax and cleaved Caspase-3. Additionally, the phosphorylation of p53 was also downregulated by miR-34c overexpression. Taken together, our findings suggest that miR-34c overexpression inhibits the Notch signaling pathway by targeting Notch1 and Jaggged1 in HG-treated podocytes, representing a novel and potential therapeutic target for the treatment of diabetic nephropathy.
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Affiliation(s)
- Xiang-Dong Liu
- Department of Nephrology, The First Affiliated Hospital of Xinxiang Medical University Weihui 453100, China
| | - Lian-Yun Zhang
- Department of Nephrology, The First Affiliated Hospital of Xinxiang Medical University Weihui 453100, China
| | - Tie-Chui Zhu
- Department of Nephrology, The First Affiliated Hospital of Xinxiang Medical University Weihui 453100, China
| | - Rui-Fang Zhang
- Department of Nephrology, The First Affiliated Hospital of Xinxiang Medical University Weihui 453100, China
| | - Shu-Long Wang
- Department of Nephrology, The First Affiliated Hospital of Xinxiang Medical University Weihui 453100, China
| | - Yan Bao
- Department of Nephrology, The First Affiliated Hospital of Xinxiang Medical University Weihui 453100, China
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Zhang Y, Li X, Pitzer AL, Chen Y, Wang L, Li PL. Coronary endothelial dysfunction induced by nucleotide oligomerization domain-like receptor protein with pyrin domain containing 3 inflammasome activation during hypercholesterolemia: beyond inflammation. Antioxid Redox Signal 2015; 22:1084-96. [PMID: 25739025 PMCID: PMC4403230 DOI: 10.1089/ars.2014.5978] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
AIMS This study hypothesized that activation of endothelial nucleotide oligomerization domain-like receptor protein with pyrin domain containing 3 (Nlrp3) inflammasomes directly produces endothelial dysfunction during hypercholesterolemia, which is distinct from its canonical roles in inflammation. RESULTS Acute hypercholesterolemia in mice was induced by intraperitoneal administration of poloxamer 407 (0.5 g/kg) for 24 h. Endothelial dysfunction was assessed by evaluating endothelium-dependent vasodilation in isolated, perfused, and pressurized coronary arteries in response to bradykinin (10(-10)-10(-6) M) and acetylcholine (10(-9)-10(-5) M). Impaired endothelium-dependent vasodilation was observed in Nlrp3(+/+) mice with acute hypercholesterolemia, which was markedly ameliorated in Nlrp3(-/-) mice. Treatment of mice with inhibitors for caspase-1 or high mobility group box 1 (HMGB1) significantly restored endothelium-dependent vasodilation in Nlrp3(+/+) mice with acute hypercholesterolemia. Confocal microscopic analysis demonstrated that hypercholesterolemia markedly increased caspase-1 activity and HMGB1 expression in coronary arterial endothelium of Nlrp3(+/+) mice, which was absent in Nlrp3-deficient mice. Further, recombinant HMGB1 directly induced endothelial dysfunction in normal Nlrp3(+/+) coronary arteries. In vitro, Nlrp3 inflammasome formation and its activity were instigated in cultured endothelial cells by cholesterol crystal, a danger factor associated with hypercholesterolemia. Moreover, cholesterol crystals directly induced endothelial dysfunction in coronary arteries from Nlrp3(+/+) mice, which was attenuated in Nlrp3(-/-) arteries. Such cholesterol crystal-induced impairment was associated with enhanced superoxide production, downregulation of endothelial nitric oxide synthase activity, and pyroptosis. INNOVATION AND CONCLUSION Our data provide the first evidence that activation of endothelial Nlrp3 inflammasome directly impairs endothelial function beyond its canonical inflammatory actions. This novel non-canonical action of Nlrp3 inflammasomes may initiate or exacerbate vascular injury during hypercholesterolemia.
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Affiliation(s)
- Yang Zhang
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University , Richmond, Virginia
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Li G, Li CX, Xia M, Ritter JK, Gehr TWB, Boini K, Li PL. Enhanced epithelial-to-mesenchymal transition associated with lysosome dysfunction in podocytes: role of p62/Sequestosome 1 as a signaling hub. Cell Physiol Biochem 2015; 35:1773-86. [PMID: 25832774 DOI: 10.1159/000373989] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/12/2015] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Autophagy is of importance in the regulation of cell differentiation and senescence in podocytes. It is possible that derangement of autophagy under different pathological conditions activates or enhances Epithelial-to-Mesenchymal Transition (EMT) in podocytes, resulting in glomerular sclerosis. To test this hypothesis, the present study produced lysosome dysfunction by inhibition of the vacuolar H(+)-ATPase (V-ATPase) to test whether deficiency of autophagic flux leads to enhancement of EMT in podocytes. METHODS AND RESULTS By Western blot and confocal analysis, lysosome inhibition using a V-ATPase inhibitor or its siRNA was found to markedly decreases the epithelial markers (P-cadherin and ZO-1) and increases the mesenchymal markers (FSP-1 and α-SMA). This enhancement was accompanied by deficient autophagic flux, as demonstrated by marked increases in LC3B-II and p62/Sequestosome 1. However, inhibition of autophagosome formation using spaudin-1 significantly attenuated both enhancement of EMT and deficiency of autophagic flux. To explore the mechanisms by which deficient autophagic flux enhances EMT, we tested the role of accumulated p62 as a signal hub in this process. Neither the nuclear factor erythroid 2-related factor 2 (Nrf2) and nuclear kappa-light-chain-enhancer pathways of p62 contributed to enhanced EMT. However, inhibition of cyclin-dependent kinase 1 (CDK1) activity reduced the phosphorylation of p62 and enhanced EMT in podocytes similar to lysosome dysfunction. CONCLUSION The lack of phosphorylated p62 leads to a faster exit from cell mitosis, enhanced EMT associated with lysosome dysfunction may be attributed to accumulation of p62 and associated reduction of p62 phosphorylation.
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Affiliation(s)
- Guangbi Li
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
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16
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Hu J, Zhu Q, Li PL, Wang W, Yi F, Li N. Stem cell conditioned culture media attenuated albumin-induced epithelial-mesenchymal transition in renal tubular cells. Cell Physiol Biochem 2015; 35:1719-28. [PMID: 25832005 PMCID: PMC4401473 DOI: 10.1159/000373984] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/27/2015] [Indexed: 12/13/2022] Open
Abstract
Background Proteinuria-induced epithelial-mesenchymal transition (EMT) plays an important role in progressive renal tubulointerstitial fibrosis in chronic renal disease. Stem cell therapy has been used for different diseases. Stem cell conditioned culture media (SCM) exhibits similar beneficial effects as stem cell therapy. The present study tested the hypothesis that SCM inhibits albumin-induced EMT in cultured renal tubular cells. Methods Rat renal tubular cells were treated with/without albumin (20 μmg/ml) plus SCM or control cell media (CCM). EMT markers and inflammatory factors were measured by Western blot and fluorescent images. Results Albumin induced EMT as shown by significant decreases in levels of epithelial marker E-cadherin, increases in mesenchymal markers fibroblast-specific protein 1 and α-smooth muscle actin, and elevations in collagen I. SCM inhibited all these changes. Meanwhile, albumin induced NF-κB translocation from cytosol into nucleus and that SCM blocked the nuclear translocation of NF-κB. Albumin also increased the levels of pro-inflammatory factor monocyte chemoattractant protein-1 (MCP)-1 by nearly 30 fold compared with control. SCM almost abolished albumin-induced increase of MCP-1. Conclusion These results suggest that SCM attenuated albumin-induced EMT in renal tubular cells via inhibiting activation of inflammatory factors, which may serve as a new therapeutic approach for chronic kidney diseases.
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Affiliation(s)
- Junping Hu
- Department of Pharmacology & Toxicology, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
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17
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Xia M, Conley SM, Li G, Li PL, Boini KM. Inhibition of hyperhomocysteinemia-induced inflammasome activation and glomerular sclerosis by NLRP3 gene deletion. Cell Physiol Biochem 2014; 34:829-41. [PMID: 25171193 DOI: 10.1159/000363046] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/01/2014] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND/AIMS Hyperhomocysteinemia (hHcys) has been reported to initiate Nod-like receptor protein 3 (NLRP3) inflammasome formation and activation in podocytes, leading to glomerular dysfunction and sclerosis. However, it remains unknown whether Nlrp3 gene is critical for the formation and activation of inflammasomes in glomeruli of hHcys mice. METHODS Plasma homocysteine concentration was estimated utilizing HPLC, inflammasome formation and immunofluorescence expression from confocal microscopy, IL-1β production from ELISA. RESULTS Uninephrectomized Nlrp3 knockout (Nlrp3(-/-)) and wild type (Nlrp3(+/+)) and intra renal Nlrp3 shRNA-transfected wild type mice (Nlrp3 shRNA) were fed a folate free (FF) diet or normal chow (ND) for 4 weeks to produce hHcys. The plasma Hcys levels were significantly elevated in both Nlrp3(-/-) and Nlrp3(+/+) mice fed a FF diet compared to ND fed mice. The FF diet significantly increased the colocalization of Nlrp3 with apoptosis-associated speck-like protein (ASC) or caspase-1, caspase-1 activity and IL-1β production in glomeruli of Nlrp3(+/+), but not in Nlrp3(-/-) mice and local Nlrp3 shRNA transfected mice. Correspondingly, the glomerular damage index (GDI) and urinary protein excretion were significantly higher in Nlrp3(+/+) mice compared to ND fed mice. However, the hHcys-induced increase in GDI and proteinuria were significantly lower in Nlrp3(-/-) and local Nlrp3 shRNA transfected mice than in Nlrp3(+/+) mice. Immunocytochemical analysis showed that hHcys decreased expression of podocin and nephrin, but increased desmin expression in glomeruli of Nlrp3(+/+) mice compared to Nlrp3(-/-) mice. CONCLUSION Nlrp3 gene is an essential component of Nlrp3 inflammasomes and that targeting Nlrp3 may be important therapeutic strategy to prevent inflammasome activation and thereby protect podocytes and glomeruli from hHcys-induced injury.
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Affiliation(s)
- Min Xia
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, School of Medicine, Richmond, VA, USA
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18
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Kamenický P, Mazziotti G, Lombès M, Giustina A, Chanson P. Growth hormone, insulin-like growth factor-1, and the kidney: pathophysiological and clinical implications. Endocr Rev 2014; 35:234-81. [PMID: 24423979 DOI: 10.1210/er.2013-1071] [Citation(s) in RCA: 137] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Besides their growth-promoting properties, GH and IGF-1 regulate a broad spectrum of biological functions in several organs, including the kidney. This review focuses on the renal actions of GH and IGF-1, taking into account major advances in renal physiology and hormone biology made over the last 20 years, allowing us to move our understanding of GH/IGF-1 regulation of renal functions from a cellular to a molecular level. The main purpose of this review was to analyze how GH and IGF-1 regulate renal development, glomerular functions, and tubular handling of sodium, calcium, phosphate, and glucose. Whenever possible, the relative contributions, the nephronic topology, and the underlying molecular mechanisms of GH and IGF-1 actions were addressed. Beyond the physiological aspects of GH/IGF-1 action on the kidney, the review describes the impact of GH excess and deficiency on renal architecture and functions. It reports in particular new insights into the pathophysiological mechanism of body fluid retention and of changes in phospho-calcium metabolism in acromegaly as well as of the reciprocal changes in sodium, calcium, and phosphate homeostasis observed in GH deficiency. The second aim of this review was to analyze how the GH/IGF-1 axis contributes to major renal diseases such as diabetic nephropathy, renal failure, renal carcinoma, and polycystic renal disease. It summarizes the consequences of chronic renal failure and glucocorticoid therapy after renal transplantation on GH secretion and action and questions the interest of GH therapy in these conditions.
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Affiliation(s)
- Peter Kamenický
- Assistance Publique-Hôpitaux de Paris (P.K., M.L., P.C.), Hôpital de Bicêtre, Service d'Endocrinologie et des Maladies de la Reproduction, Centre de Référence des Maladies Endocriniennes Rares de la Croissance, Le Kremlin Bicêtre F-94275, France; Univ Paris-Sud (P.K., M.L., P.C.), Faculté de Médecine Paris-Sud, Le Kremlin Bicêtre F-94276, France; Inserm Unité 693 (P.K., M.L., P.C.), Le Kremlin Bicêtre F-94276, France; and Department of Clinical and Experimental Sciences (A.G., G.M.), Chair of Endocrinology, University of Brescia, 25125 Brescia, Italy
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Li C, Siragy HM. High glucose induces podocyte injury via enhanced (pro)renin receptor-Wnt-β-catenin-snail signaling pathway. PLoS One 2014; 9:e89233. [PMID: 24533170 PMCID: PMC3923071 DOI: 10.1371/journal.pone.0089233] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 01/17/2014] [Indexed: 01/04/2023] Open
Abstract
(Pro)renin receptor (PRR) expression is upregulated in diabetes. We hypothesized that PRR contributes to podocyte injury via activation of Wnt-β-catenin-snail signaling pathway. Mouse podocytes were cultured in normal (5 mM) or high (25 mM) D-glucose for 3 days. Compared to normal glucose, high glucose significantly decreased mRNA and protein expressions of podocin and nephrin, and increased mRNA and protein expressions of PRR, Wnt3a, β-catenin, and snail, respectively. Confocal microscopy studies showed significant reduction in expression and reorganization of podocyte cytoskeleton protein, F-actin, in response to high glucose. Transwell functional permeability studies demonstrated significant increase in albumin flux through podocytes monolayer with high glucose. Cells treated with high glucose and PRR siRNA demonstrated significantly attenuated mRNA and protein expressions of PRR, Wnt3a, β-catenin, and snail; enhanced expressions of podocin mRNA and protein, improved expression and reorganization of F-actin, and reduced transwell albumin flux. We conclude that high glucose induces podocyte injury via PRR-Wnt-β-catenin-snail signaling pathway.
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Affiliation(s)
- Caixia Li
- Division of Endocrinology and Metabolism, University of Virginia Health System, Charlottesville, Virginia, United States of America
| | - Helmy M. Siragy
- Division of Endocrinology and Metabolism, University of Virginia Health System, Charlottesville, Virginia, United States of America
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Role of NADPH oxidase-mediated reactive oxygen species in podocyte injury. BIOMED RESEARCH INTERNATIONAL 2013; 2013:839761. [PMID: 24319690 PMCID: PMC3844218 DOI: 10.1155/2013/839761] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 09/16/2013] [Accepted: 10/04/2013] [Indexed: 02/07/2023]
Abstract
Proteinuria is an independent risk factor for end-stage renal disease (ESRD) (Shankland, 2006). Recent studies highlighted the mechanisms of podocyte injury and implications for potential treatment strategies in proteinuric kidney diseases (Zhang et al., 2012). Reactive oxygen species (ROS) are cellular signals which are closely associated with the development and progression of glomerular sclerosis. NADPH oxidase is a district enzymatic source of cellular ROS production and prominently expressed in podocytes (Zhang et al., 2010). In the last decade, it has become evident that NADPH oxidase-derived ROS overproduction is a key trigger of podocyte injury, such as renin-angiotensin-aldosterone system activation (Whaley-Connell et al., 2006), epithelial-to-mesenchymal transition (Zhang et al., 2011), and inflammatory priming (Abais et al., 2013). This review focuses on the mechanism of NADPH oxidase-mediated ROS in podocyte injury under different pathophysiological conditions. In addition, we also reviewed the therapeutic perspectives of NADPH oxidase in kidney diseases related to podocyte injury.
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Li C, Xia M, Abais JM, Liu X, Li N, Boini KM, Li PL. Protective role of growth hormone against hyperhomocysteinemia-induced glomerular injury. Naunyn Schmiedebergs Arch Pharmacol 2013; 386:551-61. [PMID: 23529346 DOI: 10.1007/s00210-013-0848-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 03/05/2013] [Indexed: 02/07/2023]
Abstract
The present study investigated the protective role of growth hormone (GH) against hyperhomocysteinemia (hHcys)-induced activations of reactive oxygen species/hypoxia-inducible factor (HIF)-1α, epithelial-mesenchymal transition (EMT), and consequent glomerular injury. A hHcys model was induced by folate free diet in mice. The urine protein excretion significantly increased while plasma GH levels dramatically decreased in hHcys. Real-time reverse transcription polymerase chain reaction showed that GH receptor (GHR) level increased in the cortex of hHcys mice, which mainly occurred in podocytes as shown by confocal microscopy. Recombinant mouse growth hormone (rmGH) treatment (0.02 mg/kg, once a day for 6 weeks) significantly restored the plasma GH, inhibited GHR upregulation and attenuated proteinuria. Correspondingly, rmGH treatment also blocked hHcys-induced decrease in the expression of podocin, a podocyte slit diaphragm molecule, and inhibited the increases in the expression of desmin, a podocyte injury marker. It was also demonstrated that in hHcys the expression of epithelial markers, p-cadherin and ZO-1, decreased, while the expression of mesenchymal markers, antifibroblast-specific protein 1 (FSP-1) and α-SMA, increased in podocytes, which together suggest the activation of EMT in podocytes. Nicotinamide adenine dinucleotide phosphate oxidase (Nox)-dependent superoxide anion (O2 (.-)) and hypoxia-inducible factor-1α (HIF-1α) level in the hHcys mice cortex was markedly enhanced. These hHcys-induced EMT enhancement and Nox-dependent O2 (.-)/HIF-1α activation were significantly attenuated by rmGH treatment. HIF-1α level increased in Hcys-treated cultured podocytes, which were blocked by rmGH treatment. Meanwhile, homocysteine (Hcys)-induced EMT in cultured podocytes was significantly reversed by HIF-1α siRNA. All these results support the view that GH ameliorates hHcys-induced glomerular injury by reducing Nox-dependent O2 (.-)/HIF-1α signal pathway and EMT.
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Affiliation(s)
- Caixia Li
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Commonwealth University, 410 N, 12th Street, Richmond, VA 23298, USA
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Han WQ, Zhu Q, Hu J, Li PL, Zhang F, Li N. Hypoxia-inducible factor prolyl-hydroxylase-2 mediates transforming growth factor beta 1-induced epithelial-mesenchymal transition in renal tubular cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:1454-62. [PMID: 23466866 DOI: 10.1016/j.bbamcr.2013.02.029] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2012] [Revised: 02/20/2013] [Accepted: 02/22/2013] [Indexed: 12/14/2022]
Abstract
Transforming growth factor beta 1 (TGF-β1)-induced epithelial-mesenchymal transition (EMT) in kidney epithelial cells plays a key role in renal tubulointerstitial fibrosis in chronic kidney diseases. As hypoxia-inducible factor (HIF)-1α is found to mediate TGF-β1-induced signaling pathway, we tested the hypothesis that HIF-1α and its upstream regulator prolyl hydroxylase domain-containing proteins (PHDs) are involved in TGF-β1-induced EMT using cultured renal tubular cells. Our results showed that TGF-β1 stimulated EMT in renal tubular cells as indicated by the significant decrease in epithelial marker P-cadherin, and the increase in mesenchymal markers α-smooth muscle actin (α-SMA) and fibroblast-specific protein 1 (FSP-1). Meanwhile, we found that TGF-β1 time-dependently increased HIF-1α and that HIF-1α siRNA significantly inhibited TGF-β1-induced EMT, suggesting that HIF-1α mediated TGF-β1 induced-EMT. Real-time PCR showed that PHD1 and PHD2, rather than PHD3, could be detected, with PHD2 as the predominant form of PHDs (PHD1:PHD2=0.21:1.0). Importantly, PHD2 mRNA and protein, but not PHD1, were decreased by TGF-β1. Furthermore, over-expression of PHD2 transgene almost fully prevented TGF-β1-induced HIF-1α accumulation and EMT marker changes, indicating that PHD2 is involved in TGF-β1-induced EMT. Finally, Smad2/3 inhibitor SB431542 prevented TGF-β1-induced PHD2 decrease, suggesting that Smad2/3 may mediate TGF-β1-induced EMT through PHD2/HIF-1α pathway. It is concluded that TGF-β1 decreased PHD2 expression via an Smad-dependent signaling pathway, thereby leading to HIF-1α accumulation and then EMT in renal tubular cells. The present study suggests that PHD2/HIF-1α is a novel signaling pathway mediating the fibrogenic effect of TGF-β1, and may be a new therapeutic target in chronic kidney diseases.
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Affiliation(s)
- Wei-Qing Han
- Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, VA, USA
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