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Sharma R, Sahoo B, Srivastava A, Tiwari S. Reduced insulin signaling and high glucagon in early insulin resistance impaired fast-fed regulation of renal gluconeogenesis via insulin receptor substrate. J Cell Biochem 2022; 123:1327-1339. [PMID: 35644013 DOI: 10.1002/jcb.30294] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 05/11/2022] [Accepted: 05/18/2022] [Indexed: 11/08/2022]
Abstract
Gluconeogenesis is one of the key processes through which the kidney contributes to glucose homeostasis. Urinary exosomes (uE) have been used to study renal gene regulation noninvasively in humans and rodents. Recently, we demonstrated fast-fed regulation of phosphoenolpyruvate carboxykinase (PEPCK), the rate-limiting enzyme for gluconeogenesis, in human uE. The regulation was impaired in subjects with early insulin resistance. Here, we studied primary human proximal tubule cells (hPT) and human uE to elucidate a potential link between insulin resistance and fast-fed regulation of renal PEPCK. We demonstrate that fasted hPTs had higher PEPCK and insulin receptor substrate-2 (IRS2) mRNA and protein levels, relative to fed cells. The fast-fed regulation was, however, attenuated in insulin receptor knockdown (IRKO) hPTs. The IRKO was confirmed by the blunted insulin-induced response on PEPCK, PGC1α, p-IR, and p-AKT expression in IRKO cells. Exosomes secreted by the wild-type or IRKO hPT showed similar regulation to the respective hPT. Similarly, in human uE, the relative abundance of IRS-2 mRNA (to IRS1) was higher in the fasted state relative to the fed condition. However, the fast-fed difference was absent in subjects with early insulin resistance. These subjects had higher circulating glucagon levels relative to subjects with optimal insulin sensitivity. Furthermore, in hPT cells, glucagon significantly induced PEPCK and IRS2 gene, and gluconeogenesis. IR knockdown in hPT cells further increased the gene expression levels. Together the data suggest that reduced insulin sensitivity and high glucagon in early insulin resistance may impair renal gluconeogenesis via IRS2 regulation.
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Affiliation(s)
- Rajni Sharma
- Department of Molecular Medicine & Biotechnology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
| | - Biswajit Sahoo
- Department of Molecular Medicine & Biotechnology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
| | - Aneesh Srivastava
- Department of Urology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
| | - Swasti Tiwari
- Department of Molecular Medicine & Biotechnology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
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Abstract
The kidneys play an important role in maintaining glucose homeostasis being the main mechanisms, the gluconeogenesis, renal glucose consumption and glucose reabsorption in the proximal tubules. In this review, we present the main research into the role of glycogen-the stored form of glucose, and how it accumulates in the cells, providing new information on the link between diabetes and diabetic kidney disease. In the last 10 years, research under the scope of renal insulin handling, glucose transport in the proximal tubules, renal gluconeogenesis and renal insulin resistance, made possible to relate the roles of glucose and glycogen in the kidney with other several organs, like the liver. On the one hand, insulin positively regulates kidney uptake and degradation, and there is probably a specific action and resistance to insulin at the renal site. Moreover, insulin regulates the bioavailability of the sodium-glucose co-transporters-SGLT2 inhibitor, and inhibits renal gluconeogenesis. Only the liver and kidneys can supply glucose to the circulation through the process of gluconeogenesis, which involves the synthesis of glucose again from non-glycemic substrates; and the decomposition of stored glycogen. In the mind of nephrologists, diabetologists and scientists, glucose metabolism in the kidney is the focus, with the relevant success of inhibitors in reducing kidney and cardiovascular diseases in individuals with diabetes. However, these new data led to the intriguing paradigm that many of the beneficial effects on the renal and cardiovascular system appear to be independent of the systemic glucose-lowering actions of these agents. The goal of this work puts in context a highly relevant research area for renal glucose metabolism, of glycogen accumulation and metabolism in the diabetic kidney.
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Affiliation(s)
- Rui Fernandes
- Instituto de Inovação e Investigação na Saúde - i3S, Universidade do Porto, Porto, Portugal
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Swe MT, Thongnak L, Jaikumkao K, Pongchaidecha A, Chatsudthipong V, Lungkaphin A. Dapagliflozin attenuates renal gluconeogenic enzyme expression in obese rats. J Endocrinol 2020; 245:193-205. [PMID: 32092034 DOI: 10.1530/joe-19-0480] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Accepted: 02/24/2020] [Indexed: 11/08/2022]
Abstract
The kidneys release glucose into the systemic circulation through glucose reabsorption and renal gluconeogenesis. Currently, the significance of renal glucose release in pathological conditions has become a subject of interest. We examined the effect of sodium-dependent glucose cotransporter 2 inhibitor (SGLT2i) on renal gluconeogenic enzyme expression in obese rats. Male Wistar rats (180-200 g) were fed either a normal diet (ND, n = 6) or a high-fat diet. At 16 weeks, after confirming the degree of glucose intolerance, high-fat diet-fed rats were randomly subdivided into three groups (n = 6/group): untreated group (HF), treated with dapagliflozin 1 mg/kg/day (HFSG) and treated with metformin 30 mg/kg/day (HFM). The treatment was continued for 4 weeks. We observed that dapagliflozin or metformin mitigated the enhanced expression of renal gluconeogenic enzymes, PEPCK, G6Pase and FBPase, as well as improved glucose tolerance and renal function in obese rats. Dapagliflozin downregulated the elevated expression of gluconeogenic transcription factors p-GSK3β, p-CREB and coactivator PGC1α in the renal cortical tissue. Metformin reduced the expression levels of renal cortical FOXO1 and CREB. Furthermore, reduced renal insulin signaling was improved and renal oxidative stress was attenuated by either dapagliflozin or metformin treatment in obese rats. We concluded that glucose tolerance was improved by dapagliflozin in obese prediabetic rats by suppressing renal glucose release from not only glucose reabsorption but also renal gluconeogenesis through improving renal cortical insulin signaling and oxidative stress. The efficacy of dapagliflozin in improving renal insulin signaling, oxidative stress and renal function was greater than that of metformin.
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Affiliation(s)
- Myat Theingi Swe
- Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
- Department of Physiology, University of Medicine 2, Yangon, Myanmar
| | - Laongdao Thongnak
- Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Krit Jaikumkao
- Department of Radiologic Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand
| | - Anchalee Pongchaidecha
- Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Varanuj Chatsudthipong
- Research Center of Transport Protein for Medical Innovation, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Anusorn Lungkaphin
- Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
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Liu Q, Zhang L, Zhang W, Hao Q, Qiu W, Wen Y, Wang H, Li X. Inhibition of NF-κB Reduces Renal Inflammation and Expression of PEPCK in Type 2 Diabetic Mice. Inflammation 2019; 41:2018-2029. [PMID: 30066289 DOI: 10.1007/s10753-018-0845-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [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] [Indexed: 02/07/2023]
Abstract
Renal gluconeogenesis is markedly promoted in patients with type 2 diabetes mellitus (T2DM); however, the underlying mechanism remains largely unknown. Renal gluconeogenesis is found to be negatively regulated by insulin. T2DM is characterized by chronic and subacute inflammation; however, inflammation has been well recognized to induce insulin resistance. Therefore, this study aimed to investigate whether the enhanced renal gluconeogenesis in T2DM was partially due to the renal inflammation-mediated insulin resistance. If so, whether inflammation inhibitor could partially reverse such change. Diabetic db/db mice and db/m mice were used in our study. Typically, diabetic db/db mice were intraperitoneally treated with 1 mg/kg NF-κB inhibitor parthenolide (PTN) or saline as control every other day. Twelve weeks after treatment, animal samples were collected for measurements. Our results suggested that the expression levels of the inflammatory factors and the gluconeogenic rate-limiting enzyme phosphoenolpyruvate carboxykinase (PEPCK) were up-regulated in renal cortex of both db/db mice and T2DM patients. Moreover, reduced insulin signaling, as well as up-regulated expression of downstream genes FOXO1 and PGC-1ɑ, could be detected in renal cortex of db/db mice compared with that of db/m mice. Consistent with our hypothesis, PTN treatment could alleviate renal inflammation and insulin resistance in db/db mice. Moreover, it could also down-regulate the renal expression of PEPCK, indicating that inflammation could be one of the triggers of insulin resistance and the enhanced renal gluconeogenesis in db/db mice. This study can shed light on the role of inflammation in the enhanced renal gluconeogenesis in T2DM, which may yield a novel target for hyperglycemia.
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Affiliation(s)
- Qianling Liu
- Department of Nephrology, Peking Union Medical College Hospital, Chinese Academy of Medicine Sciences and Peking Union Medical College, Beijing, 100730, China
| | - Liangyan Zhang
- Department of Nephrology, Peking Union Medical College Hospital, Chinese Academy of Medicine Sciences and Peking Union Medical College, Beijing, 100730, China
| | - Wei Zhang
- Department of Nephrology, Peking Union Medical College Hospital, Chinese Academy of Medicine Sciences and Peking Union Medical College, Beijing, 100730, China
| | - Qiufa Hao
- Department of Nephrology, Peking Union Medical College Hospital, Chinese Academy of Medicine Sciences and Peking Union Medical College, Beijing, 100730, China
| | - Wei Qiu
- Department of Nephrology, Peking Union Medical College Hospital, Chinese Academy of Medicine Sciences and Peking Union Medical College, Beijing, 100730, China
| | - Yubing Wen
- Department of Nephrology, Peking Union Medical College Hospital, Chinese Academy of Medicine Sciences and Peking Union Medical College, Beijing, 100730, China
| | - Haiyun Wang
- Department of Nephrology, Peking Union Medical College Hospital, Chinese Academy of Medicine Sciences and Peking Union Medical College, Beijing, 100730, China
| | - Xuemei Li
- Department of Nephrology, Peking Union Medical College Hospital, Chinese Academy of Medicine Sciences and Peking Union Medical College, Beijing, 100730, China.
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Swe MT, Pongchaidecha A, Chatsudthipong V, Chattipakorn N, Lungkaphin A. Molecular signaling mechanisms of renal gluconeogenesis in nondiabetic and diabetic conditions. J Cell Physiol 2018; 234:8134-8151. [PMID: 30370538 DOI: 10.1002/jcp.27598] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 09/19/2018] [Indexed: 12/12/2022]
Abstract
The kidneys are as involved as the liver in gluconeogenesis which can significantly contribute to hyperglycemia in the diabetic condition. Substantial evidence has demonstrated the overexpression of rate-limiting gluconeogenic enzymes, especially phosphoenolpyruvate carboxykinase and glucose 6 phosphatase, and the accelerated glucose release both in the isolated proximal tubular cells and in the kidneys of diabetic animal models and diabetic patients. The aim of this review is to provide an insight into the mechanisms that accelerate renal gluconeogenesis in the diabetic conditions and the therapeutic approaches that could affect this process in the kidney. Increase in gluconeogenic substrates, reduced insulin concentration or insulin resistance, downregulation of insulin receptors and insulin signaling, oxidative stress, and inappropriate activation of the renin-angiotensin system are likely to participate in enhancing renal gluconeogenesis in the diabetic milieu. Several studies have suggested that controlling glucose metabolism at the renal level favors effective overall glycemic control in both type 1 and type 2 diabetes. Therefore, renal gluconeogenesis may be a promising target for effective glycemic control as a therapeutic strategy in diabetes.
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Affiliation(s)
- Myat Theingi Swe
- Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Department of Physiology, University of Medicine 2, Yangon, Myanmar
| | - Anchalee Pongchaidecha
- Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Varanuj Chatsudthipong
- Research Center of Transport Protein for Medical Innovation, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Nipon Chattipakorn
- Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Anusorn Lungkaphin
- Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Center for Research and Development of Natural Products for Health, Chiang Mai University, Chiang Mai, Thailand
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Abstract
The kidney plays an important role in gluconeogenesis during starvation. To clarify the anti-diabetic action of angiotensin receptor blockers, we examined the effects of telmisartan on the sodium-glucose co-transporters (SGLT) and the pathways of renal gluconeogenesis in streptozotocin-induced diabetes mellitus (DM) rats. At 4 weeks, the DM rats treated with/without telmisartan for 2 weeks and normal control rats were used for the study after a 24-hour fast. SGLT2 expressed on the brush border membrane of the proximal convoluted tubules increased in the DM rats, but decreased in the rats treated with telmisartan. The expression of restriction enzymes of gluconeogenesis, glucose-6-phosphatase, and phosphoenolpyruvate carboxykinase increased in the proximal tubules in the DM rats, whereas these enzymes decreased in the kidneys of the rats treated with telmisartan. The elevated cytoplasmic glucose-6-phosphate and glucose levels in the kidney of DM rats significantly decreased in those treated with telmisartan, whereas those levels in the liver did not show significant change. Meanwhile, the high plasma glucose levels in the DM rats during the intravenous insulin tolerance tests were ameliorated by telmisartan. The increased fasting plasma glucose levels after 24 hours of starvation in the DM rats thus returned to the control levels by telmisartan treatment. In conclusion, the increased renal SGLT2 expression, elevated renal gluconeogenesis enzymes and extent of insulin-resistance in the DM rats were ameliorated by telmisartan therapy, thus resulting in decreased plasma glucose levels after 24 hours of fasting.
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Affiliation(s)
- Akihiro Tojo
- Division of Nephrology and Endocrinology, The University of Tokyo, Tokyo, Japan
- Correspondence: Akihiro Tojo, Division of Nephrology and Endocrinology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan, Tel +81 3 3815 5411 ext 37219, Fax +81 3 3814 0021, Email
| | - Saaya Hatakeyama
- Division of Nephrology and Endocrinology, The University of Tokyo, Tokyo, Japan
| | - Satoshi Kinugasa
- Division of Nephrology and Endocrinology, The University of Tokyo, Tokyo, Japan
| | - Masaomi Nangaku
- Division of Nephrology and Endocrinology, The University of Tokyo, Tokyo, Japan
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Abstract
Data obtained from net organ balance studies of glucose production lead to the classic view according to which glucose homeostasis is mainly ensured by the liver, and renal glucose production only plays a significant role during acidosis and prolonged starvation. Renal glucose release and uptake, as well as the participation of gluconeogenic substrates in renal gluconeogenesis, were recently re-evaluated using systemic and renal arteriovenous balance of substrates in combination with deuterated glucose dilution. Data obtained using these methods lead one to reconsider the magnitude of renal glucose production as well as its role in various physiological and pathological circumstances. These findings now conduce one to consider that renal gluconeogenesis substantially participates in postabsorptive glucose production, and that its role in glucose homeostasis is of first importance.
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Affiliation(s)
- Noël Cano
- Service d'Hépatogastroenterologie et Nutrition, Clinique Résidence du Parc, Rue Gaston Berger, 13010 Marseille, France.
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