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Xing X, Sun Q, Wang R, Wang Y, Wang R. Impacts of glutamate, an exercise-responsive metabolite on insulin signaling. Life Sci 2024; 341:122471. [PMID: 38301875 DOI: 10.1016/j.lfs.2024.122471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/24/2024] [Accepted: 01/25/2024] [Indexed: 02/03/2024]
Abstract
AIMS Disruption of the insulin signaling pathway leads to insulin resistance (IR). IR is characterized by impaired glucose and lipid metabolism. Elevated levels of circulating glutamate are correlated with metabolic indicators and may potentially predict the onset of metabolic diseases. Glutamate receptor antagonists have significantly enhanced insulin sensitivity, and improved glucose and lipid metabolism. Exercise is a well-known strategy to combat IR. The aims of our narrative review are to summarize preclinical and clinical findings to show the correlations between circulating glutamate levels, IR and metabolic diseases, discuss the causal role of excessive glutamate in IR and metabolic disturbance, and present an overview of the exercise-induced alteration in circulating glutamate levels. MATERIALS AND METHODS A literature search was conducted to identify studies on glutamate, insulin signaling, and exercise in the PubMed database. The search covered articles published from December 1955 to January 2024, using the search terms of "glutamate", "glutamic acid", "insulin signaling", "insulin resistance", "insulin sensitivity", "exercise", and "physical activity". KEY FINDINGS Elevated levels of circulating glutamate are correlated with IR. Excessive glutamate can potentially hinder the insulin signaling pathway through various mechanisms, including the activation of ectopic lipid accumulation, inflammation, and endoplasmic reticulum stress. Glutamate can also modify mitochondrial function through Ca2+ and induce purine degradation mediated by AMP deaminase 2. Exercise has the potential to decrease circulating levels of glutamate, which can be attributed to accelerated glutamate catabolism and enhanced glutamate uptake. SIGNIFICANCE Glutamate may act as a mediator in the exercise-induced improvement of insulin sensitivity.
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Affiliation(s)
- Xiaorui Xing
- School of Exercise and Health, Shanghai University of Sport, Shanghai 200438, China
| | - Qin Sun
- School of Exercise and Health, Shanghai University of Sport, Shanghai 200438, China
| | - Ruwen Wang
- School of Exercise and Health, Shanghai University of Sport, Shanghai 200438, China
| | - Yibing Wang
- School of Exercise and Health, Shanghai University of Sport, Shanghai 200438, China.
| | - Ru Wang
- School of Exercise and Health, Shanghai University of Sport, Shanghai 200438, China.
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Reduced Tyrosine and Serine-632 Phosphorylation of Insulin Receptor Substrate-1 in the Gastrocnemius Muscle of Obese Zucker Rat. Curr Issues Mol Biol 2022; 44:6015-6027. [PMID: 36547071 PMCID: PMC9777198 DOI: 10.3390/cimb44120410] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/20/2022] [Accepted: 11/21/2022] [Indexed: 12/03/2022] Open
Abstract
Obesity has become a serious health problem in the world, with increased morbidity, mortality, and financial burden on patients and health-care providers. The skeletal muscle is the most extensive tissue, severely affected by a sedentary lifestyle, which leads to obesity and type 2 diabetes. Obesity disrupts insulin signaling in the skeletal muscle, resulting in decreased glucose disposal, a condition known as insulin resistance. Although there is a large body of evidence on obesity-induced insulin resistance in various skeletal muscles, the molecular mechanism of insulin resistance due to a disruption in insulin receptor signaling, specifically in the gastrocnemius skeletal muscle of obese Zucker rats (OZRs), is not fully understood. This study subjected OZRs to a glucose tolerance test (GTT) to analyze insulin sensitivity. In addition, immunoprecipitation and immunoblotting techniques were used to determine the expression and tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1) and insulin receptor-β (IRβ), and the activation of serine-632-IRS-1 phosphorylation in the gastrocnemius muscle of Zucker rats. The results show that the GTT in the OZRs was impaired. There was a significant decrease in IRS-1 levels, but no change was observed in IRβ in the gastrocnemius muscle of OZRs, compared to Zucker leans. Obese rats had a higher ratio of tyrosine phosphorylation of IRS-1 and IRβ than lean rats. In obese rats, however, insulin was unable to induce tyrosine phosphorylation. Moreover, insulin increased the phosphorylation of serine 632-IRS-1 in the gastrocnemius muscle of lean rats. However, obese rats had a low basal level of serine-632-IRS-1 and insulin only mildly increased serine phosphorylation in obese rats, compared to those without insulin. Thus, we addressed the altered steps of the insulin receptor signal transduction in the gastrocnemius muscle of OZRs. These findings may contribute to a better understanding of human obesity and type 2 diabetes.
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Cui T, Li Y, Wei Z, Zhang X, Li W, Zhou W, Lu J, Li J, Yi X, Zeng Y, Liu C, Yan F. Pharmacokinetics, tissue distribution and excretion of a novel long-acting human insulin analogue - recombinant insulin LysArg in rats. Xenobiotica 2020; 51:307-315. [PMID: 33151101 DOI: 10.1080/00498254.2020.1847361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
As a novel long-acting recombinant human insulin analogue, it is necessary to carry out the preclinical research for insulin LysArg. The purpose of this study was to characterise the pharmacokinetic, tissue distribution and excretion of insulin LysArg and provide a reference for its development. Three methods were used to measure the content of insulin LysArg in biological samples after a single subcutaneous administration in rats, including radioassay, radioassay after precipitation with TCA and separation by HPLC. After Subcutaneous administration of recombinant insulin LysArg 1, 2, 4 U/kg in rats, it showed both Cmax and AUC0-t were positively correlated with the dose. In the meanwhile, after a single subcutaneous administration of recombinant insulin LysArg at 2 U/kg in rats, the amount of radioactivity in most organs was highest at 1.5 h and then decreased gradually, no accumulation was found. The highest level of insulin LysArg was observed in the kidney. Like other macromolecules, insulin LysArg was mainly excreted from urine. The study fully illustrated the pharmacokinetic pattern of insulin LysArg, provided valuable informations to support its further development about safety and toxicology.
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Affiliation(s)
- Tao Cui
- Tianjin Institute of Pharmaceutical Research, State Key Laboratory of Drug Delivery Technologies and Pharmacokinetics , Tianjin, China
| | - Yazhuo Li
- Tianjin Institute of Pharmaceutical Research, State Key Laboratory of Drug Delivery Technologies and Pharmacokinetics , Tianjin, China
| | - Zihong Wei
- Tianjin Institute of Pharmaceutical Research, State Key Laboratory of Drug Delivery Technologies and Pharmacokinetics , Tianjin, China
| | - Xingyan Zhang
- Tianjin University of Traditional Chinese Medicine , Tianjin, China
| | - Wei Li
- Tianjin Institute of Pharmaceutical Research, State Key Laboratory of Drug Delivery Technologies and Pharmacokinetics , Tianjin, China
| | - Wei Zhou
- Hefei Tianmai Biotechnology Development Co. Ltd , Hefei, China
| | - Jiangjie Lu
- Hefei Tianmai Biotechnology Development Co. Ltd , Hefei, China
| | - Jing Li
- Hefei Tianmai Biotechnology Development Co. Ltd , Hefei, China
| | - Xiulin Yi
- Tianjin Institute of Pharmaceutical Research, State Key Laboratory of Drug Delivery Technologies and Pharmacokinetics , Tianjin, China
| | - Yong Zeng
- Tianjin Institute of Pharmaceutical Research, State Key Laboratory of Drug Delivery Technologies and Pharmacokinetics , Tianjin, China
| | - Changxiao Liu
- Tianjin Institute of Pharmaceutical Research, State Key Laboratory of Drug Delivery Technologies and Pharmacokinetics , Tianjin, China
| | - Fengying Yan
- Tianjin Institute of Pharmaceutical Research, State Key Laboratory of Drug Delivery Technologies and Pharmacokinetics , Tianjin, China.,Research Unit for Drug Metabolism, Chinese Academy of Medical Sciences, Beijing, China
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Subirada PV, Paz MC, Ridano ME, Lorenc VE, Vaglienti MV, Barcelona PF, Luna JD, Sánchez MC. A journey into the retina: Müller glia commanding survival and death. Eur J Neurosci 2018; 47:1429-1443. [PMID: 29790615 DOI: 10.1111/ejn.13965] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 04/19/2018] [Accepted: 05/03/2018] [Indexed: 12/12/2022]
Abstract
Müller glial cells (MGCs) are known to participate actively in retinal development and to contribute to homoeostasis through many intracellular mechanisms. As there are no homologous cells in other neuronal tissues, it is certain that retinal health depends on MGCs. These macroglial cells are located at the centre of the columnar subunit and have a great ability to interact with neurons, astrocytes, microglia and endothelial cells in order to modulate different events. Several investigations have focused their attention on the role of MGCs in diabetic retinopathy, a progressive pathology where several insults coexist. As expected, data suggest that MGCs display different responses according to the severity of the stimulus, and therefore trigger distinct events throughout the course of the disease. Here, we describe physiological functions of MGCs and their participation in inflammation, gliosis, synthesis and secretion of trophic and antioxidant factors in the diabetic retina. We invite the reader to consider the protective/deleterious role of MGCs in the early and late stages of the disease. In the light of the results, we open up the discussion around and ask the question: Is it possible that the modulation of a single cell type could improve or even re-establish retinal function after an injury?
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Affiliation(s)
- Paula V Subirada
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - María C Paz
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Magali E Ridano
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Valeria E Lorenc
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.,Department of Ophthalmology, The Johns Hopkins School of Medicine, Baltimore, Maryland
| | - María V Vaglienti
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Pablo F Barcelona
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - José D Luna
- Centro Privado de Ojos Romagosa-Fundación VER, Córdoba, Argentina
| | - María C Sánchez
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
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Li J, Chen T, Li K, Yan H, Li X, Yang Y, Zhang Y, Su B, Li F. Neurolytic celiac plexus block enhances skeletal muscle insulin signaling and attenuates insulin resistance in GK rats. Exp Ther Med 2016; 11:2033-2041. [PMID: 27168847 DOI: 10.3892/etm.2016.3087] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 12/04/2015] [Indexed: 12/15/2022] Open
Abstract
Non-insulin-dependent diabetes mellitus (NIDDM) is associated with chronic inflammatory activity and disrupted insulin signaling, leading to insulin resistance (IR). The present study investigated the benefits of neurolytic celiac plexus block (NCPB) on IR in a rat NIDDM model. Goto-Kakizaki rats fed a high-fat, high-glucose diet to induce signs of NIDDM were randomly divided into NCPB and control groups; these received daily bilateral 0.5% lidocaine or 0.9% saline injections into the celiac plexus, respectively. Following 14 and 28 daily injections, rats were subject to oral glucose tolerance tests (OGTTs) or sacrificed for the analysis of serum free fatty acids (FFAs), serum inflammatory cytokines and skeletal muscle insulin signaling. Compared with controls, rats in the NCPB group demonstrated significantly (P<0.05) lower baseline, 60-min and 120-min OGTT values, lower 120-min serum insulin, lower IR [higher insulin sensitivity index (ISI1) and lower ISI2) and lower serum FFAs, tumor necrosis factor-α, interleukin (IL)-1β and IL-6. Conversely, NCPB rats exhibited higher basal and insulin-stimulated skeletal muscle glucose uptake and higher skeletal muscle insulin receptor substrate-1 (IRS-1) and glucose transporter type 4 expression. There were no differences between the groups in insulin receptor β (Rβ) or Akt expression; however Rβ-Y1162/Y1163 and Akt-S473 phosphorylation levels were higher and IRS-1-S307 phosphorylation were lower in NCPB rats than in the controls. These results indicate that NCPB improved insulin signaling and reduced IR, possibly by inhibiting inflammatory cytokine release.
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Affiliation(s)
- Jun Li
- Department of Anesthesiology, Chengdu Military General Hospital, Chengdu, Sichuan 610083, P.R. China
| | - Tao Chen
- General Surgery Center, Chengdu Military General Hospital, Chengdu, Sichuan 610083, P.R. China
| | - Kun Li
- Medical Laboratory Center, Chengdu Military General Hospital, Chengdu, Sichuan 610083, P.R. China
| | - Hongtao Yan
- General Surgery Center, Chengdu Military General Hospital, Chengdu, Sichuan 610083, P.R. China
| | - Xiaowei Li
- Department of Urology, Chengdu Military General Hospital, Chengdu, Sichuan 610083, P.R. China
| | - Yun Yang
- Medical Laboratory Center, Chengdu Military General Hospital, Chengdu, Sichuan 610083, P.R. China
| | - Yulan Zhang
- Department of Anesthesiology, Chengdu Military General Hospital, Chengdu, Sichuan 610083, P.R. China
| | - Bingyin Su
- Development and Regeneration Key Laboratory of Sichuan, Chengdu Medical College, Chengdu, Sichuan 610083, P.R. China
| | - Fuxiang Li
- Department of ICU, Chengdu Military General Hospital, Chengdu, Sichuan 610083, P.R. China
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Zhou F, Zhang Y, Chen D, Su Z, Jin L, Wang L, Hu Z, Ke Z, Song Z. Potential role of Cyr61 induced degeneration of human Müller cells in diabetic retinopathy. PLoS One 2014; 9:e109418. [PMID: 25329584 PMCID: PMC4199605 DOI: 10.1371/journal.pone.0109418] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 08/04/2014] [Indexed: 01/07/2023] Open
Abstract
The degeneration of Müller cells has been recognized to involve in the pathogenesis of diabetic retinopathy. However, the mechanism is not yet clear. This study is to explore the potential role of Cyr61, a secreted signaling protein in extracellular matrix, in inducing human Müller cell degeneration in diabetic retinopathy (DR). Twenty patients with proliferative diabetic retinopathy (PDR) and twelve non-diabetic patients were recruited for this study. Vitreous fluid was collected during vitrectomy surgery for Cyr61 ELISA. Human Müller cell line MIO-M1 were cultured to be subconfluent, and then treated with glucose (0–20 mM) or Cyr61 (0–300 ng/ml). Cyr61 expression induced by increasing concentrations of glucose was evaluated by RT-qPCR and Western blot. Effects of Cyr61 on Müller cells viability, migration and apoptosis were observed by MTT assay, Transwell assay, and TUNEL assay. Vitreous Cyr61 levels were observed to be 8-fold higher in patients with PDR (3576.92±1574.58 pg/mL), compared with non-diabetic controls (436.14±130.69 pg/mL). Interestingly, the active PDR group was significantly higher than the quiescent PDR group (P<0.01). In retinal Müller cells culture, high glucose significantly and dose-dependently elevated Cyr61 expression at both mRNA and protein levels. Cyr61 at high concentrations dose-dependently inhibited the viability and migration of Müller cells. TUNEL assay further revealed that high concentration of Cyr61 significantly promoted the cell apoptosis. In conclusion, these findings demonstrated for the first time that the expression of Cyr61 was elevated by high glucose in Müller cells, and Cyr61 inhibited cell viability and migration while induced apoptosis, suggesting the potential role of Cyr61 in Müller cell degeneration. The elevated Cyr61 levels in vitreous fluid of PDR patients further support its role in diabetic retinopathy (DR).
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Affiliation(s)
- Fen Zhou
- Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yikui Zhang
- Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Ding Chen
- Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Zhitao Su
- Eye Center, Second Affiliated Hospital, College of Medicine, Zhejiang University, China
| | - Ling Jin
- Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Lei Wang
- Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Zhixiang Hu
- Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Zhisheng Ke
- Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Zongming Song
- Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- * E-mail:
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