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Yamahara K, Yasuda-Yamahara M, Kuwagata S, Chin-Kanasaki M, Kume S. Ketone Body Metabolism in Diabetic Kidney Disease. Kidney360 2024; 5:320-326. [PMID: 38227425 PMCID: PMC10914200 DOI: 10.34067/kid.0000000000000359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 01/10/2024] [Indexed: 01/17/2024]
Abstract
Ketone bodies have a negative image because of ketoacidosis, one of the acute and serious complications in diabetes. The negative image persists despite the fact that ketone bodies are physiologically produced in the liver and serve as an indispensable energy source in extrahepatic organs, particularly during long-term fasting. However, accumulating experimental evidence suggests that ketone bodies exert various health benefits. Particularly in the field of aging research, there is growing interest in the potential organoprotective effects of ketone bodies. In addition, ketone bodies have a potential role in preventing kidney diseases, including diabetic kidney disease (DKD), a diabetic complication caused by prolonged hyperglycemia that leads to a decline in kidney function. Ketone bodies may help alleviate the renal burden from hyperglycemia by being used as an alternative energy source in patients with diabetes. Furthermore, ketone body production may reduce inflammation and delay the progression of several kidney diseases in addition to DKD. Although there is still insufficient research on the use of ketone bodies as a treatment and their effects, their renoprotective effects are being gradually proven. This review outlines the ketone body-mediated renoprotective effects in DKD and other kidney diseases.
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Affiliation(s)
- Kosuke Yamahara
- Department of Medicine, Shiga University of Medical Science, Otsu, Japan
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2
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Imai K, Ishimoto T, Doke T, Tsuboi T, Watanabe Y, Katsushima K, Suzuki M, Oishi H, Furuhashi K, Ito Y, Kondo Y, Maruyama S. Long non-coding RNA lnc-CHAF1B-3 promotes renal interstitial fibrosis by regulating EMT-related genes in renal proximal tubular cells. Mol Ther Nucleic Acids 2022; 31:139-150. [PMID: 36700051 PMCID: PMC9841231 DOI: 10.1016/j.omtn.2022.12.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 12/20/2022] [Indexed: 12/24/2022]
Abstract
Renal interstitial fibrosis (RIF) is a common pathological manifestation of chronic kidney diseases. Epithelial-mesenchymal transition (EMT) of tubular epithelial cells is considered a major cause of RIF. Although long non-coding RNAs (lncRNAs) are reportedly involved in various pathophysiological processes, the roles and underlying molecular mechanisms of lncRNAs in the progression of RIF are poorly understood. In this study, we investigated the function of lncRNAs in RIF. Microarray assays showed that expression of the lncRNA lnc-CHAF1B-3 (also called claudin 14 antisense RNA 1) was significantly upregulated in human renal proximal tubular cells by both transforming growth factor-β1 (TGF-β1) and hypoxic stimulation, accompanied with increased expression of EMT-related genes. Knockdown of lnc-CHAF1B-3 significantly suppressed TGF-β1-induced upregulated expression of collagen type I alpha 1, cadherin-2, plasminogen activator inhibitor-1, snail family transcriptional repressor I (SNAI1) and SNAI2. Quantitative reverse transcriptase PCR analyses of paraffin-embedded kidney biopsy samples from IgA nephropathy patients revealed lnc-CHAF1B-3 expression was correlated positively with urinary protein levels and correlated negatively with estimated glomerular filtration rate. In situ hybridization demonstrated that lnc-CHAF1B-3 is expressed only in proximal tubules. These findings suggest lnc-CHAF1B-3 affects the progression of RIF by regulating EMT-related signaling. Thus, lnc-CHAF1B-3 is a potential target in the treatment of RIF.
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Affiliation(s)
- Kentaro Imai
- Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Takuji Ishimoto
- Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan,Department of Nephrology and Rheumatology, Aichi Medical University, Nagakute, Aichi, 480-1195, Japan,Corresponding author: Takuji Ishimoto, Department of Nephrology and Rheumatology, Aichi Medical University, Nagakute, Aichi, 480-1195, Japan.
| | - Tomohito Doke
- Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Toshiki Tsuboi
- Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Yu Watanabe
- Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Keisuke Katsushima
- Department of Cancer Biology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Miho Suzuki
- Department of Cancer Biology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Hideto Oishi
- Department of Nephrology, Komaki City Hospital, Komaki, Aichi, 485-8520, Japan
| | - Kazuhiro Furuhashi
- Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Yasuhiko Ito
- Department of Nephrology and Rheumatology, Aichi Medical University, Nagakute, Aichi, 480-1195, Japan
| | - Yutaka Kondo
- Department of Cancer Biology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Shoichi Maruyama
- Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
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3
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Xiang X, Dong G, Zhu J, Zhang G, Dong Z. Inhibition of HDAC3 protects against kidney cold storage/transplantation injury and allograft dysfunction. Clin Sci (Lond) 2022; 136:45-60. [PMID: 34918039 DOI: 10.1042/cs20210823] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 12/06/2021] [Accepted: 12/15/2021] [Indexed: 11/17/2022]
Abstract
Cold storage/rewarming is an inevitable process for kidney transplantation from deceased donors, which correlates closely with renal ischemia-reperfusion injury (IRI) and the occurrence of delayed graft function. Histone deacetylases (HDAC) are important epigenetic regulators, but their involvement in cold storage/rewarming injury in kidney transplantation is unclear. In the present study, we showed a dynamic change of HDAC3 in a mouse model of kidney cold storage followed by transplantation. We then demonstrated that the selective HDAC3 inhibitor RGFP966 could reduce acute tubular injury and cell death after prolonged cold storage with transplantation. RGFP966 also improved renal function, kidney repair and tubular integrity when the transplanted kidney became the sole life-supporting graft in the recipient mouse. In vitro, cold storage of proximal tubular cells followed by rewarming induced remarkable cell death, which was suppressed by RGFP966 or knockdown of HDAC3 with shRNA. Inhibition of HDAC3 decreased the mitochondrial pathway of apoptosis and preserved mitochondrial membrane potential. Collectively, HDAC3 plays a pathogenic role in cold storage/rewarming injury in kidney transplantation, and its inhibition may be a therapeutic option.
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Affiliation(s)
- Xiaohong Xiang
- Department of Nephrology, Hunan Key Laboratory of Kidney Disease and Blood Purification, The Second Xiangya Hospital at Central South University, Changsha, China
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University and Charlie Norwood VA Medical Center, Augusta, GA, U.S.A
| | - Guie Dong
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University and Charlie Norwood VA Medical Center, Augusta, GA, U.S.A
| | - Jiefu Zhu
- Department of Nephrology, Hunan Key Laboratory of Kidney Disease and Blood Purification, The Second Xiangya Hospital at Central South University, Changsha, China
- Center of Nephrology and Dialysis, Transplantation, Renmin Hospital of Wuhan University, Wuhan, China
| | - Gang Zhang
- Center of Organ Transplantation, Xiangya Hospital, Central South University, Changsha, China
| | - Zheng Dong
- Department of Nephrology, Hunan Key Laboratory of Kidney Disease and Blood Purification, The Second Xiangya Hospital at Central South University, Changsha, China
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University and Charlie Norwood VA Medical Center, Augusta, GA, U.S.A
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Abstract
Acute tubular injury accounts for the most common intrinsic cause for acute kidney injury. Normally, the tubular epithelium is mitotically quiescent. However, upon injury, it can show a brisk capacity to regenerate and repair. The scattered tubular cell (STC) phenotype was discovered as a uniform reaction of tubule cells triggered by injury. The STC phenotype is characterized by a unique protein expression profile, increased robustness during tubular damage and increased proliferation. Nevertheless, the exact origin and identity of these cells have been unveiled only in part. Here, we discuss the classical concept of renal regeneration. According to this model, surviving cells dedifferentiate and divide to replace neighbouring lost tubular cells. However, this view has been challenged by the concept of a pre-existing and fixed population of intratubular progenitor cells. This review presents a significant body of previous work and animal studies using lineage-tracing methods that have investigated the regeneration of tubular cells. We review the experimental findings and discuss whether they support the progenitor hypothesis or the classical concept of renal tubular regeneration. We come to the conclusion that any proximal tubular cell may differentiate into the regenerative STC phenotype upon injury thus contributing to regeneration, and these cells differentiate back into tubular cells once regeneration is finished.
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Affiliation(s)
- Eleni Stamellou
- Division of Nephrology and Clinical Immunology, RWTH Aachen University Hospital, Aachen, Germany
| | - Katja Leuchtle
- Division of Nephrology and Clinical Immunology, RWTH Aachen University Hospital, Aachen, Germany
| | - Marcus J Moeller
- Division of Nephrology and Clinical Immunology, RWTH Aachen University Hospital, Aachen, Germany
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5
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Leite APO, Li XC, Hassan R, Zheng X, Alexander B, Casarini DE, Zhuo JL. Sex differences in angiotensin II-induced hypertension and kidney injury: role of AT1a receptors in the proximal tubule of the kidney. Clin Sci (Lond) 2021; 135:1825-1843. [PMID: 34282828 PMCID: PMC8969897 DOI: 10.1042/cs20201574] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 07/08/2021] [Accepted: 07/19/2021] [Indexed: 01/13/2023]
Abstract
In the present study, we tested the hypothesis that there are significant sex differences in angiotensin II (Ang II)-induced hypertension and kidney injury using male and female wildtype (WT) and proximal tubule-specific AT1a receptor knockout mice (PT-Agtr1a-/-). Twelve groups (n=8-12 per group) of adult male and female WT and PT-Agtr1a-/- mice were infused with a pressor dose of Ang II via osmotic minipump for 2 weeks (1.5 mg/kg/day, i.p.) and simultaneously treated with or without losartan (20 mg/kg/day, p.o.) to determine the respective roles of AT1a receptors in the proximal tubules versus systemic tissues. Basal systolic, diastolic, and mean arterial pressure were approximately 13 ± 3 mmHg lower (P<0.01), while basal 24-h urinary Na+, K+, and Cl- excretion were significantly higher in both male and female PT-Agtr1a-/- mice than WT controls (P<0.01) without significant sex differences between different strains. Both male and female WT and PT-Agtr1a-/- mice developed hypertension (P<0.01), and the magnitudes of the pressor responses to Ang II were similar between male and female WT and PT-Agtr1a-/- mice (n.s.). Likewise, Ang II-induced hypertension was significantly attenuated in both male and female PT-Agtr1a-/- mice (P<0.01). Furthermore, losartan attenuated the hypertensive responses to Ang II to similar extents in both male and female WT and PT-Agtr1a-/- mice. Finally, Ang II-induced kidney injury was attenuated in PT-Agtr1a-/- mice (P<0.01). In conclusion, the present study demonstrates that deletion of AT1a receptors in the proximal tubules of the kidney attenuates Ang II-induced hypertension and kidney injury without revealing significant sex differences.
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MESH Headings
- Angiotensin II
- Angiotensin II Type 1 Receptor Blockers/pharmacology
- Animals
- Antihypertensive Agents/pharmacology
- Arterial Pressure/drug effects
- Disease Models, Animal
- Female
- Fibrosis
- Hypertension/chemically induced
- Hypertension/metabolism
- Hypertension/physiopathology
- Hypertension/prevention & control
- Kidney Diseases/chemically induced
- Kidney Diseases/metabolism
- Kidney Diseases/physiopathology
- Kidney Diseases/prevention & control
- Kidney Tubules, Proximal/drug effects
- Kidney Tubules, Proximal/metabolism
- Kidney Tubules, Proximal/physiopathology
- Kidney Tubules, Proximal/ultrastructure
- Losartan/pharmacology
- Male
- Mice, Inbred C57BL
- Mice, Knockout
- Receptor, Angiotensin, Type 1/genetics
- Receptor, Angiotensin, Type 1/metabolism
- Renin-Angiotensin System/drug effects
- Sex Characteristics
- Sex Factors
- Signal Transduction
- Mice
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Affiliation(s)
- Ana Paula Oliveira Leite
- Department of Physiology, Tulane Hypertension and Renal Center of Excellence, Tulane University School of Medicine, New Orleans, LA 70112-2699, U.S.A
| | - Xiao C. Li
- Department of Physiology, Tulane Hypertension and Renal Center of Excellence, Tulane University School of Medicine, New Orleans, LA 70112-2699, U.S.A
| | - Rumana Hassan
- Department of Physiology, Tulane Hypertension and Renal Center of Excellence, Tulane University School of Medicine, New Orleans, LA 70112-2699, U.S.A
| | - Xiaowen Zheng
- Second Affiliated Hospital, Guangxi Medical University, Nanning, Guangxi, China
| | - Barbara Alexander
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi, U.S.A
| | - Dulce Elena Casarini
- Division of Nephrology, Department of Medicine, University of São Paulo, São Paulo, Brazil
| | - Jia L. Zhuo
- Department of Physiology, Tulane Hypertension and Renal Center of Excellence, Tulane University School of Medicine, New Orleans, LA 70112-2699, U.S.A
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Chang J, Yan J, Li X, Liu N, Zheng R, Zhong Y. Update on the Mechanisms of Tubular Cell Injury in Diabetic Kidney Disease. Front Med (Lausanne) 2021; 8:661076. [PMID: 33859992 PMCID: PMC8042139 DOI: 10.3389/fmed.2021.661076] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 03/08/2021] [Indexed: 02/06/2023] Open
Abstract
Increasing evidence supports a role of proximal tubular (PT) injury in the progression of diabetic kidney disease (DKD), in patients with or without proteinuria. Research on the mechanisms of the PT injury in DKD could help us to identify potential new biomarkers and drug targets for DKD. A high glucose transport state and mismatched local hypoxia in the PT of diabetes patients may be the initiating factors causing PT injury. Other mechanism such as mitochondrial dysfunction, reactive oxygen species (ROS) overproduction, ER stress, and deficiency of autophagy interact with each other leading to more PT injury by forming a vicious circle. PT injury eventually leads to the development of tubulointerstitial inflammation and fibrosis in DKD. Many downstream signaling pathways have been demonstrated to mediate these diseased processes. This review focuses mostly on the novel mechanisms of proximal renal tubular injury in DKD and we believe such review could help us to better understand the pathogenesis of DKD and identify potential new therapies for this disease.
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Affiliation(s)
- Jingsheng Chang
- Department of Nephrology, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Jiayi Yan
- Department of Nephrology, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Xueling Li
- Department of Nephrology, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Ni Liu
- Department of Nephrology, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Rong Zheng
- Department of Nephrology, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yifei Zhong
- Department of Nephrology, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
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Yasuda-Yamahara M, Kume S, Maegawa H. Roles of mTOR in Diabetic Kidney Disease. Antioxidants (Basel) 2021; 10:321. [PMID: 33671526 DOI: 10.3390/antiox10020321] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 02/13/2021] [Accepted: 02/18/2021] [Indexed: 02/06/2023] Open
Abstract
Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease and the number of patients affected is increasing worldwide. Thus, there is a need to establish a new treatment for DKD to improve the renal prognosis of diabetic patients. Recently, it has shown that intracellular metabolic abnormalities are involved in the pathogenesis of DKD. In particular, the activity of mechanistic target of rapamycin complex 1 (mTORC1), a nutrient-sensing signaling molecule, is hyperactivated in various organs of diabetic patients, which suggests the involvement of excessive mTORC1 activation in the pathogenesis of diabetes. In DKD, hyperactivated mTORC1 may be involved in the pathogenesis of podocyte damage, which causes proteinuria, and tubular cell injury that decreases renal function. Therefore, elucidating the role of mTORC1 in DKD and developing new therapeutic agents that suppress mTORC1 hyperactivity may shed new light on DKD treatments in the future.
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Li X, Ma TK, Wen S, Li LL, Xu L, Zhu XW, Zhang CX, Liu N, Wang X, Fan QL. LncRNA ARAP1-AS2 promotes high glucose-induced human proximal tubular cell injury via persistent transactivation of the EGFR by interacting with ARAP1. J Cell Mol Med 2020; 24:12994-13009. [PMID: 32969198 PMCID: PMC7701572 DOI: 10.1111/jcmm.15897] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 08/25/2020] [Indexed: 12/12/2022] Open
Abstract
The persistent transactivation of epidermal growth factor receptor (EGFR) causes subsequent activation of the TGF-β/Smad3 pathway, which is closely associated with fibrosis and cell proliferation in diabetic nephropathy (DN), but the exact mechanism of persistent EGFR transactivation in DN remains unclear. ARAP1, a susceptibility gene for type 2 diabetes, can regulate the endocytosis and ubiquitination of membrane receptors, but the effect of ARAP1 and its natural antisense long non-coding RNA (lncRNA), ARAP1-AS2, on the ubiquitination of EGFR in DN is not clear. In this study, we verified that the expression of ARAP1 and ARAP1-AS2 was significantly up-regulated in high glucose-induced human proximal tubular epithelial cells (HK-2 cells). Moreover, we found that overexpression or knockdown of ARAP1-AS2 could regulate fibrosis and HK-2 cell proliferation through EGFR/TGF-β/Smad3 signalling. RNA pulldown assays revealed that ARAP1-AS2 directly interacts with ARAP1. Coimmunoprecipitation, dual-immunofluorescence and ubiquitination assays showed that ARAP1 may maintain persistent EGFR activation by reducing EGFR ubiquitination through competing with Cbl for CIN85 binding. Taken together, our results suggest that the lncRNA ARAP1-AS2 may promote high glucose-induced proximal tubular cell injury via persistent EGFR/TGF-β/Smad3 pathway activation by interacting with ARAP1.
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Affiliation(s)
- Xin Li
- Department of Nephrology, First Hospital of China Medical University, Shenyang, China
| | - Tian-Kui Ma
- Department of Nephrology, First Hospital of China Medical University, Shenyang, China
| | - Si Wen
- Department of Nephrology, First Hospital of China Medical University, Shenyang, China
| | - Lu-Lu Li
- Department of Nephrology, First Hospital of China Medical University, Shenyang, China
| | - Li Xu
- Department of Clinical Laboratory, First Hospital of China Medical University, Shenyang, China
| | - Xin-Wang Zhu
- Department of Nephrology, First Hospital of China Medical University, Shenyang, China
| | - Cong-Xiao Zhang
- Department of Nephrology, First Hospital of China Medical University, Shenyang, China
| | - Nan Liu
- Department of Nephrology, First Hospital of China Medical University, Shenyang, China
| | - Xu Wang
- Department of Gastroenterology, First Hospital of China Medical University, Shenyang, China
| | - Qiu-Ling Fan
- Department of Nephrology, First Hospital of China Medical University, Shenyang, China
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Abstract
Diabetic nephropathy is a leading cause of proteinuria, kidney fibrosis, and subsequent end-stage renal disease. The renal prognosis of diabetic patients with refractory proteinuria is extremely poor. Therefore, identification of novel therapeutic targets to combat this serious condition and improve renal prognosis is urgently necessary. In diabetic patients, in addition to blood glucose levels, serum levels of free fatty acids (FFAs) are chronically elevated, even during postprandial periods. Of the various types of FFAs, saturated FFAs are highly cytotoxic and their levels are elevated in the serum of patients with diabetes. Thus, an increase in saturated FFAs is currently thought to contribute to proximal tubular cell damage and podocyte injury in diabetic nephropathy. Therefore, protecting both types of kidney cells from saturated FFA-related lipotoxicity may become a novel therapeutic approach for diabetic patients with refractory proteinuria. Interestingly, accumulating evidence suggests that controlling intracellular nutrient signals and autophagy can ameliorate the FFA-related kidney damage. Here, we review the evidence indicating possible mechanisms underlying cell injury caused by saturated FFAs and cell protective roles of intracellular nutrient signals and autophagy in diabetic nephropathy.
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Affiliation(s)
- Shinji Kume
- Department of Medicine, Shiga University of Medical Science, Otsu, Japan
| | - Hiroshi Maegawa
- Department of Medicine, Shiga University of Medical Science, Otsu, Japan
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Lee WC, Chau YY, Ng HY, Chen CH, Wang PW, Liou CW, Lin TK, Chen JB. Empagliflozin Protects HK-2 Cells from High Glucose-Mediated Injuries via a Mitochondrial Mechanism. Cells 2019; 8:E1085. [PMID: 31540085 DOI: 10.3390/cells8091085] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 09/08/2019] [Accepted: 09/13/2019] [Indexed: 02/06/2023] Open
Abstract
Empagliflozin is known to retard the progression of kidney disease in diabetic patients. However, the underlying mechanism is incompletely understood. High glucose induces oxidative stress in renal tubules, eventually leading to mitochondrial damage. Here, we investigated whether empagliflozin exhibits protective functions in renal tubules via a mitochondrial mechanism. We used human proximal tubular cell (PTC) line HK-2 and employed western blotting, terminal deoxynucleotidyl transferase dUTP nick end labelling assay, fluorescence staining, flow cytometry, and enzyme-linked immunosorbent assay to investigate the impact of high glucose and empagliflozin on cellular apoptosis, mitochondrial morphology, and functions including mitochondrial membrane potential (MMP), reactive oxygen species (ROS) production, and adenosine triphosphate (ATP) generation. We found that PTCs were susceptible to high glucose-induced mitochondrial fragmentation, and empagliflozin ameliorated this effect via the regulation of mitochondrial fission (FIS1 and DRP1) and fusion (MFN1 and MFN2) proteins. Empagliflozin reduced the high glucose-induced cellular apoptosis and improved mitochondrial functions by restoring mitochondrial ROS production, MMP, and ATP generation. Our results suggest that empagliflozin may protect renal PTCs from high glucose-mediated injuries through a mitochondrial mechanism. This could be one of the novel mechanisms explaining the benefits demonstrated in EMPA-REG OUTCOME trial.
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11
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Wang Z, Zhu Q, Wang W, Hu J, Li PL, Yi F, Li N. Downregulation of microRNA-429 contributes to angiotensin II-induced profibrotic effect in rat kidney. Am J Physiol Renal Physiol 2018; 315:F1536-F1541. [PMID: 30132344 DOI: 10.1152/ajprenal.00478.2017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
MicroRNA (miR) 429 has been shown to inhibit epithelial-to-mesenchymal transition (EMT) in cancer cells. However, the role of miR429 in EMT in non-cancer cells has not been defined, especially in the kidneys. The present study determined whether miR429 participated in angiotensin (ANG) II-induced EMT and fibrogenesis in renal cells. In NRK-52E cells, a rat proximal tubular cell line, incubation of ANG II (10-9 M) for 24 h significantly reduced the level of miR429 by 60% and increased the protein levels of mesenchymal markers α-smooth muscle actin and fibroblast-specific protein-1 by threefold and decreased epithelial marker E-cadherin by 60%, which was blocked by losartan, an AT1 receptor antagonist. Treatment of cells with miR429 inhibitor produced similar changes in the above EMT markers to that induced by ANG II. In cells overexpressed with miR429 transgene, ANG II-induced increases in collagen were abolished. Male Sprague-Dawley rats were infused with ANG II (200 ng·kg-1·min-1) for 12 days, and the levels of miR429 in the kidneys were reduced by 75%. Intrarenal transfection of lentivirus expressing miR429 also reversed the ANG II-induced changes in the EMT markers and collagen in the kidneys. The ANG II-induced increase in urinary albumin was significantly inhibited by miR429 transgene. There was no difference in the increases of blood pressure between ANG II- and ANG II+miR429 transgene-treated rats. These data suggest that ANG II-induced inhibition of miR429 contributes to ANG II-induced transdifferentiation and fibrogenesis in renal cells and that miR429 protects against ANG II-induced kidney damages.
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Affiliation(s)
- Zhengchao Wang
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University , Richmond, Virginia.,Key Laboratory for Developmental Biology and Neurosciences, College of Life Sciences, Fujian Normal University , Fuzhou , People's Republic of China
| | - Qing Zhu
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University , Richmond, Virginia.,Metabolic Disease Research Center, Guangdong Pharmaceutical University , Guangzhou , People's Republic of China
| | - Weili Wang
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University , Richmond, Virginia
| | - Junping Hu
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University , Richmond, Virginia
| | - Pin-Lan Li
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University , Richmond, Virginia
| | - Fan Yi
- Department of Pharmacology, Shandong University School of Medicine , Jinan , People's Republic of China
| | - Ningjun Li
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University , Richmond, Virginia
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12
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Li XC, Zhu D, Zheng X, Zhang J, Zhuo JL. Intratubular and intracellular renin-angiotensin system in the kidney: a unifying perspective in blood pressure control. Clin Sci (Lond) 2018; 132:1383-401. [PMID: 29986878 DOI: 10.1042/CS20180121] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 06/05/2018] [Accepted: 06/13/2018] [Indexed: 12/18/2022]
Abstract
The renin-angiotensin system (RAS) is widely recognized as one of the most important vasoactive hormonal systems in the physiological regulation of blood pressure and the development of hypertension. This recognition is derived from, and supported by, extensive molecular, cellular, genetic, and pharmacological studies on the circulating (tissue-to-tissue), paracrine (cell-to-cell), and intracrine (intracellular, mitochondrial, nuclear) RAS during last several decades. Now, it is widely accepted that circulating and local RAS may act independently or interactively, to regulate sympathetic activity, systemic and renal hemodynamics, body salt and fluid balance, and blood pressure homeostasis. However, there remains continuous debate with respect to the specific sources of intratubular and intracellular RAS in the kidney and other tissues, the relative contributions of the circulating RAS to intratubular and intracellular RAS, and the roles of intratubular compared with intracellular RAS to the normal control of blood pressure or the development of angiotensin II (ANG II)-dependent hypertension. Based on a lecture given at the recent XI International Symposium on Vasoactive Peptides held in Horizonte, Brazil, this article reviews recent studies using mouse models with global, kidney- or proximal tubule-specific overexpression (knockin) or deletion (knockout) of components of the RAS or its receptors. Although much knowledge has been gained from cell- and tissue-specific transgenic or knockout models, a unifying and integrative approach is now required to better understand how the circulating and local intratubular/intracellular RAS act independently, or with other vasoactive systems, to regulate blood pressure, cardiovascular and kidney function.
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Guo Y, Ni J, Chen S, Bai M, Lin J, Ding G, Zhang Y, Sun P, Jia Z, Huang S, Yang L, Zhang A. MicroRNA-709 Mediates Acute Tubular Injury through Effects on Mitochondrial Function. J Am Soc Nephrol 2018; 29:449-461. [PMID: 29042455 PMCID: PMC5791060 DOI: 10.1681/asn.2017040381] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 09/20/2017] [Indexed: 12/21/2022] Open
Abstract
Mitochondrial dysfunction has important roles in the pathogenesis of AKI, yet therapeutic approaches to improve mitochondrial function remain limited. In this study, we investigated the pathogenic role of microRNA-709 (miR-709) in mediating mitochondrial impairment and tubular cell death in AKI. In a cisplatin-induced AKI mouse model and in biopsy samples of human AKI kidney tissue, miR-709 was significantly upregulated in the proximal tubular cells (PTCs). The expression of miR-709 in the renal PTCs of patients with AKI correlated with the severity of kidney injury. In cultured mouse PTCs, overexpression of miR-709 markedly induced mitochondrial dysfunction and cell apoptosis, and inhibition of miR-709 ameliorated cisplatin-induced mitochondrial dysfunction and cell injury. Further analyses showed that mitochondrial transcriptional factor A (TFAM) is a target gene of miR-709, and genetic restoration of TFAM attenuated mitochondrial dysfunction and cell injury induced by cisplatin or miR-709 overexpression in vitro Moreover, antagonizing miR-709 with an miR-709 antagomir dramatically attenuated cisplatin-induced kidney injury and mitochondrial dysfunction in mice. Collectively, our results suggest that miR-709 has an important role in mediating cisplatin-induced AKI via negative regulation of TFAM and subsequent mitochondrial dysfunction. These findings reveal a pathogenic role of miR-709 in acute tubular injury and suggest a novel target for the treatment of AKI.
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Affiliation(s)
- Yan Guo
- Department of Nephrology, State Key Laboratory of Reproductive Medicine, Children's Hospital of Nanjing Medical University, Nanjing, China
- Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing, China
| | - Jiajia Ni
- Department of Nephrology, State Key Laboratory of Reproductive Medicine, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Shuang Chen
- Department of Nephrology, State Key Laboratory of Reproductive Medicine, Children's Hospital of Nanjing Medical University, Nanjing, China
- Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing, China
| | - Mi Bai
- Department of Nephrology, State Key Laboratory of Reproductive Medicine, Children's Hospital of Nanjing Medical University, Nanjing, China
- Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing, China
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University, Nanjing, China; and
| | - Jiajuan Lin
- Department of Nephrology, State Key Laboratory of Reproductive Medicine, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Guixia Ding
- Department of Nephrology, State Key Laboratory of Reproductive Medicine, Children's Hospital of Nanjing Medical University, Nanjing, China
- Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing, China
| | - Yue Zhang
- Department of Nephrology, State Key Laboratory of Reproductive Medicine, Children's Hospital of Nanjing Medical University, Nanjing, China
- Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing, China
| | - Pingping Sun
- Renal Division, Peking University First Hospital, Beijing, China
| | - Zhanjun Jia
- Department of Nephrology, State Key Laboratory of Reproductive Medicine, Children's Hospital of Nanjing Medical University, Nanjing, China
- Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing, China
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University, Nanjing, China; and
| | - Songming Huang
- Department of Nephrology, State Key Laboratory of Reproductive Medicine, Children's Hospital of Nanjing Medical University, Nanjing, China
- Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing, China
| | - Li Yang
- Renal Division, Peking University First Hospital, Beijing, China
| | - Aihua Zhang
- Department of Nephrology, State Key Laboratory of Reproductive Medicine, Children's Hospital of Nanjing Medical University, Nanjing, China;
- Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing, China
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University, Nanjing, China; and
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Sarközi R, Corazza U, Osterkamp JP, Pirklbauer M, Mayer G, Schramek H. Synergistic induction of CCL2/MCP-1 expression driven by oncostatin M and IL-1β in human proximal tubular cells depends on STAT3 and p65 NFκB/RelA. Physiol Rep 2015; 3:3/2/e12298. [PMID: 25713326 PMCID: PMC4393206 DOI: 10.14814/phy2.12298] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
In response to tubular injury, production, and secretion of cytokines, chemokines or extracellular matrix components by human proximal tubular epithelial cells (PTC) directly contribute to the development of tubulointerstitial inflammation and fibrosis. Here, we report a novel stimulatory and synergistic effect of oncostatin M (OSM) on proinflammatory CCL2/MCP-1 mRNA expression in human PTC. Although OSM inhibited IL-1β- and TNF-α-mediated mRNA expression of matricellular proteins TSP-1 and tenascin C (TNC), it acted synergistically with these two proinflammatory cytokines to induce CCL2 mRNA expression for up to 24 h. Stimulation of two independent human PTC lines with OSM alone led to a rapid and strong induction of this chemokine within the first hour of ligand administration, which subsequently returned toward basal levels in between 3 and 24 h and finally switched into a significant OSM-mediated 70% inhibition of basal CCL2 mRNA expression after 48 h of incubation. In contrast to OSM, which stimulated both STAT1/3 and ERK1/2 signaling, IL-1β led to a strong phosphorylation of p65 NFκB/RelA, SMAD2/3, and p38 MAPK in human PTC. Selective silencing of these signaling molecules revealed that p65 NFκB/RelA is involved in IL-1β-mediated stimulation of CCL2 mRNA, and that superinduction of CCL2 mRNA expression in the presence of both OSM and IL-1β at least partially depends on STAT3 signaling. Thus, with respect to the expression of the proinflammatory chemokine CCL2, OSM may stimulate acute inflammation via its synergistic effect with other proinflammatory cytokines early after injury.
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Affiliation(s)
- Rita Sarközi
- Department of Internal Medicine IV, Nephrology and Hypertension, Medical University of Innsbruck, Innsbruck, Austria
| | - Ulrike Corazza
- Department of Internal Medicine IV, Nephrology and Hypertension, Medical University of Innsbruck, Innsbruck, Austria
| | - Jan-Philipp Osterkamp
- Department of Internal Medicine IV, Nephrology and Hypertension, Medical University of Innsbruck, Innsbruck, Austria
| | - Markus Pirklbauer
- Department of Internal Medicine IV, Nephrology and Hypertension, Medical University of Innsbruck, Innsbruck, Austria
| | - Gert Mayer
- Department of Internal Medicine IV, Nephrology and Hypertension, Medical University of Innsbruck, Innsbruck, Austria
| | - Herbert Schramek
- Department of Internal Medicine IV, Nephrology and Hypertension, Medical University of Innsbruck, Innsbruck, Austria
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15
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Lindahl E, Nordquist L, Müller P, El Agha E, Friederich M, Dahlman-Wright K, Palm F, Jörnvall H. Early transcriptional regulation by C-peptide in freshly isolated rat proximal tubular cells. Diabetes Metab Res Rev 2011; 27:697-704. [PMID: 21618400 DOI: 10.1002/dmrr.1220] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Revised: 03/06/2011] [Accepted: 05/17/2011] [Indexed: 12/17/2022]
Abstract
BACKGROUND Clinical studies have shown that proinsulin C-peptide exerts renoprotective effects in type 1 diabetes, although the underlying mechanisms are poorly understood. As C-peptide has been shown to induce several intracellular events and to localize to nuclei, we aimed to determine whether gene transcription is affected in proximal tubular kidney cells, and if so, whether the genes with altered transcription include those related to protective mechanisms. METHODS The effect of C-peptide incubation (2 h) on gene expression was investigated in freshly isolated proximal tubular cells from streptozotocin-diabetic Sprague-Dawley rats using global gene expression profiling and real-time quantitative polymerase chain reaction. Protein expression was assayed using western blotting. Different bioinformatic strategies were employed. RESULTS Gene transcription profiling demonstrated differential transcription of 492 genes (p < 0.01) after 2 h of C-peptide exposure, with the majority of these genes repressed (83%). Real-time quantitative polymerase chain reaction validation supported a trend of several G protein-coupled receptors being activated, and certain transcription factors being repressed. Also, C-peptide repressed the transcription of genes associated with the pathways of circulatory and inflammatory diseases. CONCLUSION This study shows that C-peptide exerts early effects on gene transcription in proximal tubular cells. The findings also bring further knowledge to the renoprotective mechanisms of C-peptide in type 1 diabetes, and support a transcriptional activity for C-peptide. It is suggested that C-peptide may play a regulatory role in the gene expression of proximal tubular cells.
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Affiliation(s)
- Emma Lindahl
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
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