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Hayashi D, Mouchlis VD, Okamoto S, Namba T, Wang L, Li S, Ueda S, Yamanoue M, Tachibana H, Arai H, Ashida H, Dennis EA, Shirai Y. Vitamin E functions by association with a novel binding site on the 67 kDa laminin receptor activating diacylglycerol kinase. J Nutr Biochem 2022; 110:109129. [PMID: 35977663 PMCID: PMC10243646 DOI: 10.1016/j.jnutbio.2022.109129] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 03/27/2022] [Accepted: 07/16/2022] [Indexed: 01/13/2023]
Abstract
It is generally recognized that the main function of α-tocopherol (αToc), which is the most active form of vitamin E, is its antioxidant effect, while non-antioxidant effects have also been reported. We previously found that αToc ameliorates diabetic nephropathy via diacylglycerol kinase alpha (DGKα) activation in vivo, and the activation was not related to the antioxidant effect. However, the underlying mechanism of how αToc activates DGKα have been enigmatic. We report that the membrane-bound 67 kDa laminin receptor (67LR), which has previously been shown to serve as a receptor for epigallocatechin gallate (EGCG), also contains a novel binding site for vitamin E, and its association with Vitamin E mediates DGKα activation by αToc. We employed hydrogen-deuterium exchange mass spectrometry (HDX/MS) and molecular dynamics (MD) simulations to identify the specific binding site of αToc on the 67LR and discovered the conformation of the specific hydrophobic pocket that accommodates αToc. Also, HDX/MS and MD simulations demonstrated the detailed binding of EGCG to a water-exposed hydrophilic site on 67LR, while in contrast αToc binds to a distinct hydrophobic site. We demonstrated that 67LR triggers an important signaling pathway mediating non-antioxidant effects of αToc, such as DGKα activation. This is the first evidence demonstrating a membrane receptor for αToc and one of the underlying mechanisms of a non-antioxidant function for αToc.
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Affiliation(s)
- Daiki Hayashi
- Department of Applied Chemistry in Bioscience, Graduate School of Agricultural Science, Faculty of Agriculture, Kobe University, Kobe, Japan; Department of Pharmacology, and Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, USA
| | - Varnavas D Mouchlis
- Department of Pharmacology, and Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, USA
| | - Seika Okamoto
- Department of Applied Chemistry in Bioscience, Graduate School of Agricultural Science, Faculty of Agriculture, Kobe University, Kobe, Japan
| | - Tomoka Namba
- Department of Applied Chemistry in Bioscience, Graduate School of Agricultural Science, Faculty of Agriculture, Kobe University, Kobe, Japan
| | - Liuqing Wang
- Department of Applied Chemistry in Bioscience, Graduate School of Agricultural Science, Faculty of Agriculture, Kobe University, Kobe, Japan
| | - Sheng Li
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Shuji Ueda
- Department of Applied Chemistry in Bioscience, Graduate School of Agricultural Science, Faculty of Agriculture, Kobe University, Kobe, Japan
| | - Minoru Yamanoue
- Department of Applied Chemistry in Bioscience, Graduate School of Agricultural Science, Faculty of Agriculture, Kobe University, Kobe, Japan
| | - Hirofumi Tachibana
- Division of Applied Biological Chemistry, Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
| | - Hiroyuki Arai
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo Japan
| | - Hitoshi Ashida
- Department of Applied Chemistry in Bioscience, Graduate School of Agricultural Science, Faculty of Agriculture, Kobe University, Kobe, Japan
| | - Edward A Dennis
- Department of Pharmacology, and Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, USA
| | - Yasuhito Shirai
- Department of Applied Chemistry in Bioscience, Graduate School of Agricultural Science, Faculty of Agriculture, Kobe University, Kobe, Japan.
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The Role of Diacylglycerol Kinase in the Amelioration of Diabetic Nephropathy. Molecules 2022; 27:molecules27206784. [PMID: 36296376 PMCID: PMC9607625 DOI: 10.3390/molecules27206784] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 10/05/2022] [Accepted: 10/07/2022] [Indexed: 12/02/2022] Open
Abstract
The drastic increase in the number of patients with diabetes and its complications is a global issue. Diabetic nephropathy, the leading cause of chronic kidney disease, significantly affects patients’ quality of life and medical expenses. Furthermore, there are limited drugs for treating diabetic nephropathy patients. Impaired lipid signaling, especially abnormal protein kinase C (PKC) activation by de novo-synthesized diacylglycerol (DG) under high blood glucose, is one of the causes of diabetic nephropathy. DG kinase (DGK) is an enzyme that phosphorylates DG and generates phosphatidic acid, i.e., DGK can inhibit PKC activation under diabetic conditions. Indeed, it has been proven that DGK activation ameliorates diabetic nephropathy. In this review, we summarize the involvement of PKC and DGK in diabetic nephropathy as therapeutic targets, and its mechanisms, by referring to our recent study.
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Lane BM, Chryst-Stangl M, Wu G, Shalaby M, El Desoky S, Middleton CC, Huggins K, Sood A, Ochoa A, Malone AF, Vancini R, Miller SE, Hall G, Kim SY, Howell DN, Kari JA, Gbadegesin R. Steroid-sensitive nephrotic syndrome candidate gene CLVS1 regulates podocyte oxidative stress and endocytosis. JCI Insight 2022; 7:e152102. [PMID: 34874915 PMCID: PMC9018043 DOI: 10.1172/jci.insight.152102] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 12/01/2021] [Indexed: 11/17/2022] Open
Abstract
We performed next-generation sequencing in patients with familial steroid-sensitive nephrotic syndrome (SSNS) and identified a homozygous segregating variant (p.H310Y) in the gene encoding clavesin-1 (CLVS1) in a consanguineous family with 3 affected individuals. Knockdown of the clavesin gene in zebrafish (clvs2) produced edema phenotypes due to disruption of podocyte structure and loss of glomerular filtration barrier integrity that could be rescued by WT CLVS1 but not the p.H310Y variant. Analysis of cultured human podocytes with CRISPR/Cas9-mediated CLVS1 knockout or homozygous H310Y knockin revealed deficits in clathrin-mediated endocytosis and increased susceptibility to apoptosis that could be rescued with corticosteroid treatment, mimicking the steroid responsiveness observed in patients with SSNS. The p.H310Y variant also disrupted binding of clavesin-1 to α-tocopherol transfer protein, resulting in increased reactive oxygen species (ROS) accumulation in CLVS1-deficient podocytes. Treatment of CLVS1-knockout or homozygous H310Y-knockin podocytes with pharmacological ROS inhibitors restored viability to control levels. Taken together, these data identify CLVS1 as a candidate gene for SSNS, provide insight into therapeutic effects of corticosteroids on podocyte cellular dynamics, and add to the growing evidence of the importance of endocytosis and oxidative stress regulation to podocyte function.
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Affiliation(s)
- Brandon M. Lane
- Department of Pediatrics, Division of Nephrology, and Duke Molecular Physiology Institute, Duke University School of Medicine, Durham, North Carolina, USA
| | - Megan Chryst-Stangl
- Department of Pediatrics, Division of Nephrology, and Duke Molecular Physiology Institute, Duke University School of Medicine, Durham, North Carolina, USA
| | - Guanghong Wu
- Department of Pediatrics, Division of Nephrology, and Duke Molecular Physiology Institute, Duke University School of Medicine, Durham, North Carolina, USA
| | - Mohamed Shalaby
- Pediatric Department, Pediatric Nephrology Center of Excellence, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Sherif El Desoky
- Pediatric Department, Pediatric Nephrology Center of Excellence, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Claire C. Middleton
- Department of Pediatrics, Division of Nephrology, and Duke Molecular Physiology Institute, Duke University School of Medicine, Durham, North Carolina, USA
| | - Kinsie Huggins
- Department of Pediatrics, Division of Nephrology, and Duke Molecular Physiology Institute, Duke University School of Medicine, Durham, North Carolina, USA
| | - Amika Sood
- Department of Biostatistics and Bioinformatics and Duke Center for Statistical Genetics and Genomics, Duke University, Durham, North Carolina, USA
| | - Alejandro Ochoa
- Department of Biostatistics and Bioinformatics and Duke Center for Statistical Genetics and Genomics, Duke University, Durham, North Carolina, USA
| | - Andrew F. Malone
- Department of Medicine, Division of Nephrology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | | | | | - Gentzon Hall
- Department of Pediatrics, Division of Nephrology, and Duke Molecular Physiology Institute, Duke University School of Medicine, Durham, North Carolina, USA
- Department of Medicine, Division of Nephrology; and
| | - So Young Kim
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA
| | | | - Jameela A. Kari
- Pediatric Department, Pediatric Nephrology Center of Excellence, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Rasheed Gbadegesin
- Department of Pediatrics, Division of Nephrology, and Duke Molecular Physiology Institute, Duke University School of Medicine, Durham, North Carolina, USA
- Department of Medicine, Division of Nephrology; and
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Hayashi D, Wang L, Ueda S, Yamanoue M, Ashida H, Shirai Y. The mechanisms of ameliorating effect of a green tea polyphenol on diabetic nephropathy based on diacylglycerol kinase α. Sci Rep 2020; 10:11790. [PMID: 32678222 PMCID: PMC7366667 DOI: 10.1038/s41598-020-68716-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 06/16/2020] [Indexed: 12/19/2022] Open
Abstract
Significant efforts have been made to ameliorate diabetic nephropathy (DN) by inhibiting protein kinase C. However, these efforts have not been successful in human trials, suggesting that novel therapeutic strategies are required. Thus far, it has been reported that green tea polyphenol epigallocatechin gallate (EGCg) improved albuminuria in DN in a human trial. Our previous study revealed that activation of diacylglycerol kinase α (DGKα) plays a crucial role in the amelioration of DN and that EGCg activates DGKα. Here, we investigated whether and how DGKα contributes to the amelioration of DN upon stimulation by EGCg by using streptozotocin-induced type 1 diabetic model mice. Our results revealed that EGCg ameliorated albuminuria in DN through DGKα in vivo, and methylated EGCg, which has higher absorption in the plasma improved albuminuria in DN effectively. Additionally, we showed that c-Src mediated EGCg-induced DGKα translocation and colocalized with the 67 kDa laminin receptor, which is an EGCg receptor. Furthermore, EGCg attenuated the loss of podocytes in DN by preventing a decrease in focal adhesion under high glucose conditions. Our results indicate that the DGKα pathway is an attractive therapeutic target and that activating this pathway is a novel strategy for treating DN.
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Affiliation(s)
- Daiki Hayashi
- Department of Applied Chemistry in Bioscience, Graduate School of Agricultural Science, Kobe University, Rokkodai-Cho 1-1, Nada-Ku, Kobe, 657-8501, Japan
| | - Liuqing Wang
- Department of Applied Chemistry in Bioscience, Graduate School of Agricultural Science, Kobe University, Rokkodai-Cho 1-1, Nada-Ku, Kobe, 657-8501, Japan
| | - Shuji Ueda
- Department of Applied Chemistry in Bioscience, Graduate School of Agricultural Science, Kobe University, Rokkodai-Cho 1-1, Nada-Ku, Kobe, 657-8501, Japan
| | - Minoru Yamanoue
- Department of Applied Chemistry in Bioscience, Graduate School of Agricultural Science, Kobe University, Rokkodai-Cho 1-1, Nada-Ku, Kobe, 657-8501, Japan
| | - Hitoshi Ashida
- Department of Applied Chemistry in Bioscience, Graduate School of Agricultural Science, Kobe University, Rokkodai-Cho 1-1, Nada-Ku, Kobe, 657-8501, Japan
| | - Yasuhito Shirai
- Department of Applied Chemistry in Bioscience, Graduate School of Agricultural Science, Kobe University, Rokkodai-Cho 1-1, Nada-Ku, Kobe, 657-8501, Japan.
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Chen J, Wu J, Kong D, Yang C, Yu H, Pan Q, Liu W, Ding Y, Liu H. The Effect of Antioxidant Vitamins on Patients With Diabetes and Albuminuria: A Meta-Analysis of Randomized Controlled Trials. J Ren Nutr 2019; 30:101-110. [PMID: 31466888 DOI: 10.1053/j.jrn.2019.06.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 06/22/2019] [Accepted: 06/29/2019] [Indexed: 12/21/2022] Open
Abstract
OBJECTIVE This study aimed to investigate the effect of antioxidant vitamins, including vitamins E and C, on patients with diabetes and albuminuria by conducting a meta-analysis of randomized controlled trials. DESIGN The PubMed, Embase, CENTRAL (the Cochrane Central Register of Controlled Trials at the Cochrane Library), Web of Science, OVID, and www.clinicaltrials.gov (latest search: December 10, 2018) databases were searched. This study was limited to randomized controlled trials. Patients with diabetes and albuminuria were included regardless of diabetic type, and patients must have received treatment with vitamins C or E. RESULTS Ten studies, representing 445 participants, were identified for analysis. Antioxidant vitamins had significant effects on serum creatinine levels (mean difference = -0.11 mg/dL, 95% confidence interval -0.19 to -0.03, P = .007) and systolic pressure (mean difference = -6.02 mm Hg, 95% confidence interval -9.65 to -2.40, P = .001) with low heterogeneity. Antioxidant vitamins had no effect on albuminuria or proteinuria, diastolic blood pressure, glucose, or lipid metabolism. CONCLUSION This meta-analysis indicated that antioxidant vitamins can benefit kidney function and systolic blood pressure in patients with diabetes and albuminuria. Further studies with larger sample sizes and longer follow-up are needed to completely understand the effect of antioxidant vitamins in these patients.
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Affiliation(s)
- Jinxia Chen
- Key Laboratory of Prevention and Management of Chronic Kidney Disease of Zhanjiang City, Affiliated Hospital of Guangdong Medical University, Zhanjiang, People's Republic of China
| | - Jiayuan Wu
- Department of Clinical Research, Affiliated Hospital of Guangdong Medical University, Zhanjiang, People's Republic of China
| | - Danli Kong
- Department of Epidemiology and Medical Statistics, Guangdong Medical University, Zhanjiang, People's Republic of China
| | - Chen Yang
- Key Laboratory of Prevention and Management of Chronic Kidney Disease of Zhanjiang City, Affiliated Hospital of Guangdong Medical University, Zhanjiang, People's Republic of China
| | - Haibing Yu
- Department of Epidemiology and Medical Statistics, Guangdong Medical University, Dongguan, People's Republic of China
| | - Qingjun Pan
- Key Laboratory of Prevention and Management of Chronic Kidney Disease of Zhanjiang City, Affiliated Hospital of Guangdong Medical University, Zhanjiang, People's Republic of China
| | - Weijing Liu
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Beijing, People's Republic of China
| | - Yuanlin Ding
- Department of Epidemiology and Medical Statistics, Guangdong Medical University, Dongguan, People's Republic of China.
| | - Huafeng Liu
- Key Laboratory of Prevention and Management of Chronic Kidney Disease of Zhanjiang City, Affiliated Hospital of Guangdong Medical University, Zhanjiang, People's Republic of China.
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