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Cheng D, Liu X, Gao Y, Cui L, Wang M, Zheng Y, Lv W, Zhao L, Liu J. α-Ketoglutarate Attenuates Hyperlipidemia-Induced Endothelial Damage by Activating the Erk-Nrf2 Signaling Pathway to Inhibit Oxidative Stress and Mitochondrial Dysfunction. Antioxid Redox Signal 2023; 39:777-793. [PMID: 37154729 DOI: 10.1089/ars.2022.0215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Aims: α-Ketoglutarate (AKG) is an intermediate of the tricarboxylic acid cycle and a key hub linking amino acid metabolism and glucose oxidation. Previous studies have shown that AKG improved cardiovascular diseases such as myocardial infarction and myocardial hypertrophy through antioxidant and lipid-lowering characteristics. However, its protective effect and mechanism on endothelial injury caused by hyperlipidemia have not been elucidated yet. In this study, we tested whether AKG possesses protective effects on hyperlipidemia-induced endothelial injury and studied the mechanism. Results: AKG administration both in vivo, and in vitro significantly suppressed the hyperlipidemia-induced endothelial damage, regulated ET-1 and nitric oxide levels, and reduced the inflammatory factor interleukin-6 and matrix metallopeptidase-1 by inhibiting oxidative stress and mitochondrial dysfunction. The protective effects were achieved by the mechanism of activating the Nrf2 phase II system through the ERK signaling pathway. Innovation: These results reveal the role of the AKG-ERK-Nrf2 signaling pathway in the prevention of hyperlipidemia-induced endothelial damage, and suggest that AKG, as a mitochondria-targeting nutrient, is a potential drug for the treatment of endothelial damage in hyperlipidemia. Conclusion: AKG ameliorated the hyperlipidemia-induced endothelial damage and inflammatory response by inhibiting oxidative stress and mitochondrial dysfunction. Antioxid. Redox Signal. 39, 777-793.
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Affiliation(s)
- Danyu Cheng
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Center for Mitochondrial Biology and Medicine, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Xuyun Liu
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Center for Mitochondrial Biology and Medicine, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Yilin Gao
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Center for Mitochondrial Biology and Medicine, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Li Cui
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Center for Mitochondrial Biology and Medicine, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Min Wang
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Center for Mitochondrial Biology and Medicine, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Yezi Zheng
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Center for Mitochondrial Biology and Medicine, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Weiqiang Lv
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Center for Mitochondrial Biology and Medicine, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Lin Zhao
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Center for Mitochondrial Biology and Medicine, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Jiankang Liu
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Center for Mitochondrial Biology and Medicine, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
- School of Health and Life Sciences, University of Health and Rehabilitation Sciences, Qingdao, China
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Liu L, Zhang W, Liu T, Tan Y, Chen C, Zhao J, Geng H, Ma C. The physiological metabolite α-ketoglutarate ameliorates osteoarthritis by regulating mitophagy and oxidative stress. Redox Biol 2023; 62:102663. [PMID: 36924682 PMCID: PMC10026041 DOI: 10.1016/j.redox.2023.102663] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 02/18/2023] [Accepted: 03/07/2023] [Indexed: 03/11/2023] Open
Abstract
Osteoarthritis (OA) is an age-related metabolic disease. Low-grade inflammation and oxidative stress are the last common pathway of OA. α-ketoglutarate (α-KG) is an essential physiological metabolite from the mitochondrial tricarboxylic acid (TCA) cycle, with multiple functions, including anti-inflammation and antioxidation, and exhibits decreased serum levels with age. Herein, we aimed to investigate the effect and mechanism of α-KG on OA. We first quantified the α-KG levels in human cartilage tissue and osteoarthritic chondrocytes induced by IL-1β. Besides, IL-1β-induced osteoarthritic chondrocytes were treated with different concentrations of α-KG. Chondrocyte proliferation and apoptosis, synthesis and degradation of extracellular matrix, and inflammation mediators were analyzed. RNA sequencing was used to explore the mechanism of α-KG, and mitophagy and oxidative stress levels were further detected. These results were verified in an anterior cruciate ligament transection (ACLT) induced age-related OA rat model. We found that α-KG content decreased by 31.32% in damaged medial cartilage than in normal lateral cartilage and by 36.85% in IL-1β-induced human osteoarthritic chondrocytes compared to control. α-KG supplementation reversed IL-1β-induced chondrocyte proliferation inhibition and apoptosis, increased the transcriptomic and proteinic expression of ACAN and COL2A1 in vivo and in vitro, but inhibited the expression of MMP13, ADAMTS5, IL-6, and TNF-α. In mechanism, α-KG promoted mitophagy and inhibited ROS generation, and these effects could be prevented by Mdivi-1 (a mitophagy inhibitor). Overall, α-KG content decreased in human OA cartilage and IL-1β-induced osteoarthritic chondrocytes. Moreover, α-KG supplementation could alleviate osteoarthritic phenotype by regulating mitophagy and oxidative stress, suggesting its potential as a therapeutic target to ameliorate OA.
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Affiliation(s)
- Liang Liu
- Department of Orthopedic Surgery, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China
| | - Wanying Zhang
- Department of Infectious Diseases, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009, China
| | - Tanghao Liu
- Department of Orthopedics, The First Affiliated Hospital of Jishou University, Jishou, 416000, China
| | - Yangfan Tan
- Department of Orthopedics, The First Affiliated Hospital of Jishou University, Jishou, 416000, China
| | - Cheng Chen
- Department of Orthopedics, The Affiliated 926 Hospital of Kunming University of Science and Technology, Kaiyuan, China
| | - Jun Zhao
- Department of Orthopedics, The First Affiliated Hospital of Jishou University, Jishou, 416000, China.
| | - Huan Geng
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009, China.
| | - Chi Ma
- Department of Orthopedics, The First Affiliated Hospital of Jishou University, Jishou, 416000, China; Department of Orthopedic Surgery, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China.
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Si X, Song Z, Liu N, Jia H, Liu H, Wu Z. α-Ketoglutarate Restores Intestinal Barrier Function through Promoting Intestinal Stem Cells-Mediated Epithelial Regeneration in Colitis. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:13882-13892. [PMID: 36269035 DOI: 10.1021/acs.jafc.2c04641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
This study investigated the preventive effects of α-ketoglutarate (α-KG, in the form of sodium salt) on a Citrobacter rodentium (CR)-induced colitis and explored potential mechanisms. The results demonstrated that CR caused body weight loss and colon length shortening, which were abrogated by the α-KG administration. The colon length of mice in the α-KG plus CR group was significantly higher than that of mice in the CR group (6.9 ± 0.59 (mean ± SD) vs 6.1 ± 0.55; P < 0.05). This beneficial effect was associated with regulating endoplasmic reticulum (ER) stress signaling. In addition, small intestinal organoids generated from intestinal crypts of mice were exposed to α-KG in the presence of TNF-α or IWR-1 to assess stem cell activity in vitro. The results demonstrated that TNF-α exposure decreased the viability of organoids and impaired barrier function by suppressing Wnt signaling, which was abolished by α-KG. Interestingly, the protective effect of α-KG on intestinal barrier function was abrogated by the inhibitor of Wnt signaling in the intestinal organoids. Taken together, α-KG restored barrier function by regulating ER stress and activating Wnt/β-catenin-medicated intestinal stem cell proliferation and differentiation.
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Affiliation(s)
- Xuemeng Si
- State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing 100193, China
| | - Zhuan Song
- State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing 100193, China
| | - Ning Liu
- State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing 100193, China
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Nutrition and Health, China Agricultural University, Beijing 100193, China
| | - Hai Jia
- State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing 100193, China
| | - Haozhen Liu
- State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing 100193, China
| | - Zhenlong Wu
- State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing 100193, China
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Nutrition and Health, China Agricultural University, Beijing 100193, China
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Kostiuchenko O, Lushnikova I, Kowalczyk M, Skibo G. mTOR/α-ketoglutarate-mediated signaling pathways in the context of brain neurodegeneration and neuroprotection. BBA ADVANCES 2022; 2:100066. [PMID: 37082603 PMCID: PMC10074856 DOI: 10.1016/j.bbadva.2022.100066] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 11/15/2022] [Indexed: 11/18/2022] Open
Abstract
Cerebral disorders are largely associated with impaired cellular metabolism, despite the regulatory mechanisms designed to ensure cell viability and adequate brain function. Mechanistic target of rapamycin (mTOR) signaling is one of the most crucial factors in the regulation of energy homeostasis and its imbalance is linked with a variety of neurodegenerative diseases. Recent advances in the metabolic pathways' modulation indicate the role of α-ketoglutarate (AKG) as a major signaling hub, additionally highlighting its anti-aging and neuroprotective properties, but the mechanisms of its action are not entirely clear. In this review, we analyzed the physiological and pathophysiological aspects of mTOR in the brain. We also discussed AKG's multifunctional properties, as well as mTOR/AKG-mediated functional communications in cellular metabolism. Thus, this article provides a broad overview of the mTOR/AKG-mediated signaling pathways, in the context of neurodegeneration and endogenous neuroprotection, with the aim to find novel therapeutic strategies.
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Dietary Alpha-Ketoglutarate Partially Abolishes Adverse Changes in the Small Intestine after Gastric Bypass Surgery in a Rat Model. Nutrients 2022; 14:nu14102062. [PMID: 35631203 PMCID: PMC9146360 DOI: 10.3390/nu14102062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 05/04/2022] [Accepted: 05/12/2022] [Indexed: 02/03/2023] Open
Abstract
Alpha-ketoglutarate (AKG) is one of the key metabolites that play a crucial role in cellular energy metabolism. Bariatric surgery is a life-saving procedure, but it carries many gastrointestinal side effects. The present study investigated the beneficial effects of dietary AKG on the structure, integrity, and absorption surface of the small intestine after bariatric surgery. Male 7-week-old Sprague Dowley rats underwent gastric bypass surgery, after which they received AKG, 0.2 g/kg body weight/day, administered in drinking water for 6 weeks. Changes in small intestinal morphology, including histomorphometric parameters of enteric plexuses, immunolocalization of claudin 3, MarvelD3, occludin and zonula ocludens 1 in the intestinal mucosa, and selected hormones, were evaluated. Proliferation, mucosal and submucosal thickness, number of intestinal villi and Paneth cells, and depth of crypts were increased; however, crypt activity, the absorption surface, the expression of claudin 3, MarvelD3, occludin and zonula ocludens 1 in the intestinal epithelium were decreased after gastric bypass surgery. Alpha-ketoglutarate supplementation partially improved intestinal structural parameters and epithelial integrity in rats undergoing this surgical procedure. Dietary AKG can abolish adverse functional changes in the intestinal mucosa, enteric nervous system, hormonal response, and maintenance of the intestinal barrier that occurred after gastric bypass surgery.
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Gyanwali B, Lim ZX, Soh J, Lim C, Guan SP, Goh J, Maier AB, Kennedy BK. Alpha-Ketoglutarate dietary supplementation to improve health in humans. Trends Endocrinol Metab 2022; 33:136-146. [PMID: 34952764 DOI: 10.1016/j.tem.2021.11.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/09/2021] [Accepted: 11/11/2021] [Indexed: 01/02/2023]
Abstract
Alpha-ketoglutarate (AKG) is an intermediate in the Krebs cycle involved in various metabolic and cellular pathways. As an antioxidant, AKG interferes in nitrogen and ammonia balance, and affects epigenetic and immune regulation. These pleiotropic functions of AKG suggest it may also extend human healthspan. Recent studies in worms and mice support this concept. A few studies published in the 1980s and 1990s in humans suggested the potential benefits of AKG in muscle growth, wound healing, and in promoting faster recovery after surgery. So far there are no recently published studies demonstrating the role of AKG in treating aging and age-related diseases; hence, further clinical studies are required to better understand the role of AKG in humans. This review will discuss the regulatory role of AKG in aging, as well as its potential therapeutic use in humans to treat age-related diseases.
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Affiliation(s)
- Bibek Gyanwali
- Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Zi Xiang Lim
- Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Janjira Soh
- Centre for Healthy Longevity, National University Health System, Singapore
| | - Clarissa Lim
- Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Shou Ping Guan
- Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Jorming Goh
- Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Centre for Healthy Longevity, National University Health System, Singapore; Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Andrea B Maier
- Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Centre for Healthy Longevity, National University Health System, Singapore; Department of Medicine and Aged Care, @AgeMelbourne, The Royal Melbourne Hospital, The University of Melbourne, Parkville, Victoria, Australia; Department of Human Movement Sciences, @AgeAmsterdam, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands
| | - Brian K Kennedy
- Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Centre for Healthy Longevity, National University Health System, Singapore; Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Singapore Institute of Clinical Sciences, A*STAR, Singapore.
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Zhang Z, He C, Gao Y, Zhang L, Song Y, Zhu T, Zhu K, Lv D, Wang J, Tian X, Ma T, Ji P, Cui W, Liu G. α-ketoglutarate delays age-related fertility decline in mammals. Aging Cell 2021; 20:e13291. [PMID: 33450127 PMCID: PMC7884030 DOI: 10.1111/acel.13291] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 11/22/2020] [Accepted: 11/29/2020] [Indexed: 12/15/2022] Open
Abstract
The fecundity reduction with aging is referred as the reproductive aging which comes earlier than that of chronological aging. Since humans have postponed their childbearing age, to prolong the reproductive age becomes urgent agenda for reproductive biologists. In the current study, we examined the potential associations of α-ketoglutarate (α-KG) and reproductive aging in mammals including mice, swine, and humans. There is a clear tendency of reduced α-KG level with aging in the follicle fluids of human. To explore the mechanisms, mice were selected as the convenient animal model. It is observed that a long term of α-KG administration preserves the ovarian function, the quality and quantity of oocytes as well as the telomere maintaining system in mice. α-KG suppresses ATP synthase and alterations of the energy metabolism trigger the nutritional sensors to down-regulate mTOR pathway. These events not only benefit the general aging process but also maintain ovarian function and delay the reproductive decline. Considering the safety of the α-KG as a naturally occurring molecule in energy metabolism, its utility in reproduction of large mammals including humans deserves further investigation.
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Affiliation(s)
- Zhenzhen Zhang
- National Engineering Laboratory for Animal Breeding Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture Beijing Key Laboratory for Animal Genetic Improvement College of Animal Science and Technology China Agricultural University Beijing China
| | - Changjiu He
- National Engineering Laboratory for Animal Breeding Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture Beijing Key Laboratory for Animal Genetic Improvement College of Animal Science and Technology China Agricultural University Beijing China
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction Education Ministry of China College of Animal Science and Technology Huazhong Agricultural University Wuhan China
| | - Yu Gao
- National Engineering Laboratory for Animal Breeding Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture Beijing Key Laboratory for Animal Genetic Improvement College of Animal Science and Technology China Agricultural University Beijing China
- College of Animal Science and Technology Xinjiang Agricultural University Wulumuqi China
| | - Lu Zhang
- National Engineering Laboratory for Animal Breeding Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture Beijing Key Laboratory for Animal Genetic Improvement College of Animal Science and Technology China Agricultural University Beijing China
| | - Yukun Song
- National Engineering Laboratory for Animal Breeding Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture Beijing Key Laboratory for Animal Genetic Improvement College of Animal Science and Technology China Agricultural University Beijing China
- College of Animal Science and Technology Xinjiang Agricultural University Wulumuqi China
| | - Tianqi Zhu
- National Engineering Laboratory for Animal Breeding Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture Beijing Key Laboratory for Animal Genetic Improvement College of Animal Science and Technology China Agricultural University Beijing China
| | - Kuanfeng Zhu
- National Engineering Laboratory for Animal Breeding Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture Beijing Key Laboratory for Animal Genetic Improvement College of Animal Science and Technology China Agricultural University Beijing China
| | - Dongying Lv
- National Engineering Laboratory for Animal Breeding Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture Beijing Key Laboratory for Animal Genetic Improvement College of Animal Science and Technology China Agricultural University Beijing China
| | - Jing Wang
- National Engineering Laboratory for Animal Breeding Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture Beijing Key Laboratory for Animal Genetic Improvement College of Animal Science and Technology China Agricultural University Beijing China
| | - Xiuzhi Tian
- National Engineering Laboratory for Animal Breeding Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture Beijing Key Laboratory for Animal Genetic Improvement College of Animal Science and Technology China Agricultural University Beijing China
- Institute of Animal Science Chinese Academy of Agricultural Sciences Beijing China
| | - Teng Ma
- National Engineering Laboratory for Animal Breeding Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture Beijing Key Laboratory for Animal Genetic Improvement College of Animal Science and Technology China Agricultural University Beijing China
- Institute of Animal Science Chinese Academy of Agricultural Sciences Beijing China
| | - Pengyun Ji
- National Engineering Laboratory for Animal Breeding Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture Beijing Key Laboratory for Animal Genetic Improvement College of Animal Science and Technology China Agricultural University Beijing China
| | - Wei Cui
- National Engineering Laboratory for Animal Breeding Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture Beijing Key Laboratory for Animal Genetic Improvement College of Animal Science and Technology China Agricultural University Beijing China
- Department of Surgery & Cancer Imperial College London London United Kingdom
| | - Guoshi Liu
- National Engineering Laboratory for Animal Breeding Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture Beijing Key Laboratory for Animal Genetic Improvement College of Animal Science and Technology China Agricultural University Beijing China
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Alpha-Ketoglutarate as a Molecule with Pleiotropic Activity: Well-Known and Novel Possibilities of Therapeutic Use. Arch Immunol Ther Exp (Warsz) 2016; 65:21-36. [PMID: 27326424 PMCID: PMC5274648 DOI: 10.1007/s00005-016-0406-x] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 02/22/2016] [Indexed: 12/17/2022]
Abstract
Alpha-ketoglutarate (AKG), an endogenous intermediary metabolite in the Krebs cycle, is a molecule involved in multiple metabolic and cellular pathways. It functions as an energy donor, a precursor in the amino acid biosynthesis, a signalling molecule, as well as a regulator of epigenetic processes and cellular signalling via protein binding. AKG is an obligatory co-substrate for 2-oxoglutarate-dependent dioxygenases, which catalyse hydroxylation reactions on various types of substrates. It regulates the activity of prolyl-4 hydroxylase, which controls the biosynthesis of collagen, a component of bone tissue. AKG also affects the functioning of prolyl hydroxylases, which, in turn, influences the function of the hypoxia-inducible factor, an important transcription factor in cancer development and progression. Additionally, it affects the functioning of enzymes that influence epigenetic modifications of chromatin: ten-eleven translocation hydroxylases involved in DNA demethylation and the Jumonji C domain containing lysine demethylases, which are the major histone demethylases. Thus, it regulates gene expression. The metabolic and extrametabolic function of AKG in cells and the organism open many different fields for therapeutic interventions for treatment of diseases. This review presents the results of studies conducted with the use of AKG in states of protein deficiency and oxidative stress conditions. It also discusses current knowledge about AKG as an immunomodulatory agent and a bone anabolic factor. Additionally, the regulatory role of AKG and its structural analogues in carcinogenesis as well as the results of studies of AKG as an anticancer agent are discussed.
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Bienholz A, Petrat F, Wenzel P, Ickerott P, Weinberg JM, Witzke O, Kribben A, de Groot H, Feldkamp T. Adverse effects of α-ketoglutarate/malate in a rat model of acute kidney injury. Am J Physiol Renal Physiol 2012; 303:F56-63. [PMID: 22513847 PMCID: PMC3431145 DOI: 10.1152/ajprenal.00070.2012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 04/11/2012] [Indexed: 01/22/2023] Open
Abstract
Acute kidney injury (AKI) is the most common kidney disease in hospitalized patients with high mortality. Ischemia and reperfusion (I/R) is one of the major causes of AKI. The combination of α-ketoglutarate+malate (αKG/MAL) showed the ability to reduce hypoxia-induced damage to isolated proximal tubules. The present study utilizes a rat model of I/R-induced AKI accompanied by intensive biomonitoring to examine whether αKG/MAL provides protection in vivo. AKI was induced in male Sprague-Dawley rats by bilateral renal clamping (40 min) followed by reperfusion (240 min). αKG/MAL was infused continuously for 60 min before and 45 min after ischemia. Normoxic and I/R control groups received 0.9% NaCl solution. The effect of αKG/MAL was evaluated by biomonitoring, blood and plasma parameters, histopathology, and immunohistochemical staining for kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL), as well as by determination of tissue ATP and nonesterified fatty acid concentrations. Intravenous infusion of αKG/MAL at a cumulative dose of 1 mmol/kg each (146 mg/kg αKG and 134 mg/kg MAL) did not prevent I/R-induced increases in plasma creatinine, histopathological alterations, or cortical ATP depletion. On the contrary, the most notable adverse affect in animals receiving αKG/MAL was the decrease in mean arterial blood pressure, which was also accompanied by a reduction in heart rate. Supplementation with αKG/MAL, which is very protective against hypoxia-induced injury in isolated proximal tubules, does not protect against I/R-induced renal injury in vivo, possibly due to cardiovascular depressive effects.
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Affiliation(s)
- Anja Bienholz
- Department of Nephrology, University Duisburg-Essen, Germany.
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