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Sundaram K, Teng Y, Mu J, Xu Q, Xu F, Sriwastva MK, Zhang L, Park JW, Zhang X, Yan J, Zhang SQ, Merchant ML, Chen SY, McClain CJ, Dryden GW, Zhang HG. Outer Membrane Vesicles Released from Garlic Exosome-like Nanoparticles (GaELNs) Train Gut Bacteria that Reverses Type 2 Diabetes via the Gut-Brain Axis. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2308680. [PMID: 38225709 PMCID: PMC11102339 DOI: 10.1002/smll.202308680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 12/19/2023] [Indexed: 01/17/2024]
Abstract
Gut microbiota function has numerous effects on humans and the diet humans consume has emerged as a pivotal determinant of gut microbiota function. Here, a new concept that gut microbiota can be trained by diet-derived exosome-like nanoparticles (ELNs) to release healthy outer membrane vesicles (OMVs) is introduced. Specifically, OMVs released from garlic ELN (GaELNs) trained human gut Akkermansia muciniphila (A. muciniphila) can reverse high-fat diet-induced type 2 diabetes (T2DM) in mice. Oral administration of OMVs released from GaELNs trained A. muciniphila can traffick to the brain where they are taken up by microglial cells, resulting in inhibition of high-fat diet-induced brain inflammation. GaELNs treatment increases the levels of OMV Amuc-1100, P9, and phosphatidylcholines. Increasing the levels of Amuc-1100 and P9 leads to increasing the GLP-1 plasma level. Increasing the levels of phosphatidylcholines is required for inhibition of cGas and STING-mediated inflammation and GLP-1R crosstalk with the insulin pathway that leads to increasing expression of Insulin Receptor Substrate (IRS1 and IRS2) on OMV targeted cells. These findings reveal a molecular mechanism whereby OMVs from plant nanoparticle-trained gut bacteria regulate genes expressed in the brain, and have implications for the treatment of brain dysfunction caused by a metabolic syndrome.
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Affiliation(s)
- Kumaran Sundaram
- Brown Cancer Center, University of Louisville, Louisville, KY40202, USA
| | - Yun Teng
- Brown Cancer Center, University of Louisville, Louisville, KY40202, USA
| | - Jingyao Mu
- Brown Cancer Center, University of Louisville, Louisville, KY40202, USA
| | - Qingbo Xu
- Department of Microbiology & Immunology, University of Louisville, Louisville, KY40202, USA
| | - Fangyi Xu
- Brown Cancer Center, University of Louisville, Louisville, KY40202, USA
| | | | - Lifeng Zhang
- Brown Cancer Center, University of Louisville, Louisville, KY40202, USA
| | - Juw Won Park
- Department of Computer Science and Engineering, University of Louisville, Louisville, KY40202, USA
- Kentucky IDeA Network of Biomedical Research Excellence Bioinformatics Core, University of Louisville, Louisville, KY 40202, USA
| | - Xiang Zhang
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY 40202, USA
| | - Jun Yan
- Brown Cancer Center, University of Louisville, Louisville, KY40202, USA
| | - Shuang Qin Zhang
- Section of Hematology/Oncology, University of Chicago, Chicago, IL 60637
| | - Michael L. Merchant
- Kidney Disease Program and Clinical Proteomics Center, University of Louisville, Louisville, KY, USA
| | - Shao-yu Chen
- Brown Cancer Center, University of Louisville, Louisville, KY40202, USA
| | - Craig J McClain
- Robley Rex Veterans Affairs Medical Center, Louisville, KY 40206, USA
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY 40202, USA
| | - Gerald W Dryden
- Robley Rex Veterans Affairs Medical Center, Louisville, KY 40206, USA
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY 40202, USA
| | - Huang-Ge Zhang
- Robley Rex Veterans Affairs Medical Center, Louisville, KY 40206, USA
- Brown Cancer Center, University of Louisville, Louisville, KY40202, USA
- Department of Microbiology & Immunology, University of Louisville, Louisville, KY40202, USA
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Gugliucci A. The chylomicron saga: time to focus on postprandial metabolism. Front Endocrinol (Lausanne) 2024; 14:1322869. [PMID: 38303975 PMCID: PMC10830840 DOI: 10.3389/fendo.2023.1322869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 12/28/2023] [Indexed: 02/03/2024] Open
Abstract
Since statins have had such tremendous therapeutic success over the last three decades, the field of atherosclerosis has become somewhat LDL-centric, dismissing the relevance of triglycerides (TG), particularly chylomicrons, in atherogenesis. Nonetheless, 50% of patients who take statins are at risk of developing atherosclerotic cardiovascular disease (ASCVD) and are unable to achieve their goal LDL-C levels. This residual risk is mediated, in part by triglyceride rich lipoproteins (TRL) and their remnants. Following his seminal investigation on the subject, Zilversmit proposed that atherosclerosis is a postprandial event in 1979 (1-4). In essence, the concept suggests that remnant cholesterol-rich chylomicron (CM) and very-low density lipoprotein (VLDL) particles play a role in atherogenesis. Given the foregoing, this narrative review addresses the most recent improvements in our understanding of postprandial dyslipidemia. The primary metabolic pathways of chylomicrons are discussed, emphasizing the critical physiological role of lipoprotein lipase and apoCIII, the importance of these particles' fluxes in the postprandial period, their catabolic rate, the complexities of testing postprandial metabolism, and the role of angiopoietin-like proteins in the partition of CM during the fed cycle. The narrative is rounded out by the dysregulation of postprandial lipid metabolism in insulin resistance states and consequent CVD risk, the clinical evaluation of postprandial dyslipidemia, current research limits, and potential future study directions.
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Affiliation(s)
- Alejandro Gugliucci
- Glycation, Oxidation and Disease Laboratory, Department of Research, Touro University California, Vallejo, CA, United States
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Le TDV, Liu D, Besing GLK, Raghavan R, Ellis BJ, Ceddia RP, Collins S, Ayala JE. Glucagon-like peptide-1 receptor activation stimulates PKA-mediated phosphorylation of Raptor and this contributes to the weight loss effect of liraglutide. eLife 2023; 12:e80944. [PMID: 37930356 PMCID: PMC10691799 DOI: 10.7554/elife.80944] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 11/03/2023] [Indexed: 11/07/2023] Open
Abstract
The canonical target of the glucagon-like peptide-1 receptor (GLP-1R), Protein Kinase A (PKA), has been shown to stimulate mechanistic Target of Rapamycin Complex 1 (mTORC1) by phosphorylating the mTOR-regulating protein Raptor at Ser791 following β-adrenergic stimulation. The objective of these studies is to test whether GLP-1R agonists similarly stimulate mTORC1 via PKA phosphorylation of Raptor at Ser791 and whether this contributes to the weight loss effect of the therapeutic GLP-1R agonist liraglutide. We measured phosphorylation of the mTORC1 signaling target ribosomal protein S6 in Chinese Hamster Ovary cells expressing GLP-1R (CHO-Glp1r) treated with liraglutide in combination with PKA inhibitors. We also assessed liraglutide-mediated phosphorylation of the PKA substrate RRXS*/T* motif in CHO-Glp1r cells expressing Myc-tagged wild-type (WT) Raptor or a PKA-resistant (Ser791Ala) Raptor mutant. Finally, we measured the body weight response to liraglutide in WT mice and mice with a targeted knock-in of PKA-resistant Ser791Ala Raptor. Liraglutide increased phosphorylation of S6 and the PKA motif in WT Raptor in a PKA-dependent manner but failed to stimulate phosphorylation of the PKA motif in Ser791Ala Raptor in CHO-Glp1r cells. Lean Ser791Ala Raptor knock-in mice were resistant to liraglutide-induced weight loss but not setmelanotide-induced (melanocortin-4 receptor-dependent) weight loss. Diet-induced obese Ser791Ala Raptor knock-in mice were not resistant to liraglutide-induced weight loss; however, there was weight-dependent variation such that there was a tendency for obese Ser791Ala Raptor knock-in mice of lower relative body weight to be resistant to liraglutide-induced weight loss compared to weight-matched controls. Together, these findings suggest that PKA-mediated phosphorylation of Raptor at Ser791 contributes to liraglutide-induced weight loss.
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Affiliation(s)
- Thao DV Le
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of MedicineNashvilleUnited States
| | - Dianxin Liu
- Department of Medicine, Vanderbilt University Medical CenterNashvilleUnited States
| | - Gai-Linn K Besing
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of MedicineNashvilleUnited States
| | - Ritika Raghavan
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of MedicineNashvilleUnited States
| | - Blair J Ellis
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of MedicineNashvilleUnited States
| | - Ryan P Ceddia
- Department of Medicine, Vanderbilt University Medical CenterNashvilleUnited States
| | - Sheila Collins
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of MedicineNashvilleUnited States
- Department of Medicine, Vanderbilt University Medical CenterNashvilleUnited States
| | - Julio E Ayala
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of MedicineNashvilleUnited States
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Mahalingam S, Bellamkonda R, Arumugam MK, Perumal SK, Yoon J, Casey C, Kharbanda K, Rasineni K. Glucagon-like peptide 1 receptor agonist, exendin-4, reduces alcohol-associated fatty liver disease. Biochem Pharmacol 2023; 213:115613. [PMID: 37209859 PMCID: PMC10351880 DOI: 10.1016/j.bcp.2023.115613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 05/06/2023] [Accepted: 05/15/2023] [Indexed: 05/22/2023]
Abstract
Fatty liver is the earliest response to excessive ethanol consumption, which increases the susceptibility of the liver to develop advanced stage of liver disease. Our previous studies have revealed that chronic alcohol administration alters metabolic hormone levels and their functions. Of current interest to our laboratory is glucagon-like peptide 1 (GLP-1), a widely studied hormone known to reduce insulin resistance and hepatic fat accumulation in patients with metabolic-associated fatty liver disease. In this study, we examined the beneficial effects of exendin-4 (a GLP-1 receptor agonist) in an experimental rat model of ALD. Male Wistar rats were pair-fed the Lieber-DeCarli control or ethanol diet. After 4 weeks of this feeding regimen, a subset of rats in each group were intraperitoneally injected every other day with either saline or exendin-4 at a dose of 3 nmol/kg/day (total 13 doses) while still being fed their respective diet. At the end of the treatment, rats were fasted for 6 h and glucose tolerance test was conducted. The following day, the rats were euthanized, and the blood and tissue samples collected for subsequent analysis. We found that exendin-4 treatment had no significant effect on body weight gain among the experimental groups. Exendin-4-treated ethanol rats exhibited improved alcohol-induced alterations in liver/body weight and adipose/body weight ratio, serum ALT, NEFA, insulin, adiponectin and hepatic triglyceride levels. Reduction in indices of hepatic steatosis in exendin-4 treated ethanol-fed rats was attributed to improved insulin signaling and fat metabolism. These results strongly suggest that exendin-4 mitigates alcohol-associated hepatic steatosis by regulating fat metabolism.
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Affiliation(s)
- Sundararajan Mahalingam
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE, United States; Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, United States
| | - Ramesh Bellamkonda
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE, United States; Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, United States
| | - Madan Kumar Arumugam
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE, United States; Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE, United States
| | - Sathish Kumar Perumal
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE, United States; Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE, United States
| | - Jessica Yoon
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE, United States; Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, United States
| | - Carol Casey
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE, United States; Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, United States; Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE, United States
| | - Kusum Kharbanda
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE, United States; Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, United States; Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE, United States
| | - Karuna Rasineni
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE, United States; Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, United States; Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE, United States.
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5
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Barron M, Hayes H, Fernando DG, Geurts AM, Kindel TL. Sleeve Gastrectomy Improves High-Fat Diet-Associated Hepatic Steatosis Independent of the Glucagon-like-Petpide-1 Receptor in Rats. J Gastrointest Surg 2022; 26:1607-1618. [PMID: 35618993 PMCID: PMC9444920 DOI: 10.1007/s11605-022-05361-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 05/14/2022] [Indexed: 01/31/2023]
Abstract
BACKGROUND The gastrointestinal hormone glucagon-like peptide-1 (GLP-1) is increased after sleeve gastrectomy (SG). Rat and clinical studies support, while mouse studies refute, a role for GLP-1R signaling after SG. Therefore, we developed a global GLP-1R knockout (KO) rat to test the hypothesis that a functional GLP-1R is critical to induce weight loss and metabolic disease improvement after SG. METHODOLOGY A 4 bp deletion was created in exon 2 of the GLP-1R gene on a Lewis strain background to create a global GLP-1R KO rat. KO and Lewis rats were placed on a high-fat or low-fat diet and phenotyped followed by SG or Sham surgery and assessed for the effect of GLP-1R KO on surgical and metabolic efficacy. RESULTS Loss of the GLP-1R created an obesity-prone rodent without changes in energy expenditure. Both male and female KO rats had significantly greater insulin concentrations after an oral glucose gavage, augmented by a high-fat diet, compared to Lewis rats despite similar glucose concentrations. GLP-1R KO caused hepatomegaly and increased triglyceride deposition compared to Lewis rats. We found no difference between SG GLP-1R KO and Lewis groups when considering efficacy on body weight, glucose tolerance, and a robustly preserved improvement in fatty liver disease. CONCLUSIONS Loss of the GLP-1R in rats resulted in increased adiposity, insulin resistance, and severe steatosis. A functional GLP-1R is not critical to the metabolic efficacy of SG in Lewis rats, similar to mouse studies, but importantly including steatosis, supporting a GLP-1R-independent mechanism for the improvement in fatty liver disease after SG.
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Affiliation(s)
- Matthew Barron
- Department of Surgery, Division of Gastrointestinal and Minimally Invasive Surgery, Medical College of Wisconsin, 8900 W. Doyne Avenue, Milwaukee, WI, 53226, USA
| | - Hailey Hayes
- Medical College of Wisconsin School of Medicine, Medical College of Wisconsin, 8900 W. Doyne Avenue, Milwaukee, WI, 53226, USA
| | - Deemantha G Fernando
- Department of Surgery, Division of Gastrointestinal and Minimally Invasive Surgery, Medical College of Wisconsin, 8900 W. Doyne Avenue, Milwaukee, WI, 53226, USA
| | - Aron M Geurts
- Department of Physiology, Medical College of Wisconsin, 8900 W. Doyne Avenue, Milwaukee, WI, 53226, USA
| | - Tammy L Kindel
- Department of Surgery, Division of Gastrointestinal and Minimally Invasive Surgery, Medical College of Wisconsin, 8900 W. Doyne Avenue, Milwaukee, WI, 53226, USA.
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Peng X, Shi X, Huang J, Zhang S, Yan Y, Ma D, Xu W, Xu W, Dong K, Tao J, Li M, Yang Y. Exendin-4 Improves Cognitive Function of Diabetic Mice via Increasing Brain Insulin Synthesis. Curr Alzheimer Res 2021; 18:546-557. [PMID: 34587885 DOI: 10.2174/1567205018666210929150004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 06/16/2021] [Accepted: 08/24/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND AND OBJECTIVE Type 2 diabetes(T2D) patients are more prone to develop Alzheimer's disease (AD). We have previously shown that Glucagon-like peptide-1 receptor agon- ist exendin-4 (Ex-4) reduces tau hyperphosphorylation in T2D animals through upregulating in- sulin signaling, and peripheral injected Ex-4 increases insulin levels in the T2D brain. This study aims to further clarify whether the elevated insulin in the brain is produced by nerve cells under the action of Ex-4. METHODS The neuronal cell line-HT22 was treated with Ex-4 under high glucose or normal cultiva- tion, and the number of insulin-positive cells as well as the expression levels of insulin synthesis-re- lated genes were examined. The db/db mice were treated with a peripheral injection of Ex-4 and/or intracerebroventricular (ICV) injection of siRNA to inhibit the expression of insulin synthesis-relat- ed genes and the behavior tests were carried on. Finally, plasma glucose, cerebrospinal fluid (CSF) glucose, CSF insulin, phosphorylation of tau, phosphorylation of AKT and GSK-3β of db/db mice were detected. RESULTS We found that Ex-4 promoted the expression of insulin synthesis-related genes and in- duced an obvious increase of insulin-positive HT-22 neuronal cells in a high glucose environment. Peripheral injection of Ex-4 improved the cognitive function of db/db mice and increased brain in- sulin levels which activated brain insulin signaling and subsequently alleviated tau hyperphosphory- lation. However, when siRNA-neurod1 was injected to block insulin synthesis, the cognitive func- tion of db/db mice was not improved under the action of Ex-4 anymore. Moreover, the brain in- sulin levels dropped to an extremely low level, and the phosphorylation level of tau increased signi- ficantly. CONCLUSION This study demonstrated that Ex-4 improved cognition function by promoting brain in- sulin synthesis followed by the activation of brain insulin signaling and alleviation of tau hyper- phosphorylation.
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Affiliation(s)
- Xuemin Peng
- Department of Endocrinology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei. China
| | - Xiaoli Shi
- Department of Endocrinology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei. China
| | - Jiaojiao Huang
- Department of Endocrinology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei. China
| | - Shujun Zhang
- Department of Endocrinology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei. China
| | - Yongli Yan
- Department of Endocrinology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei. China
| | - Delin Ma
- Department of Endocrinology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei. China
| | - Weijie Xu
- Department of Endocrinology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei. China
| | - Weijie Xu
- Department of Endocrinology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei. China
| | - Kun Dong
- Department of Endocrinology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei. China
| | - Jing Tao
- Department of Endocrinology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei. China
| | - Mengni Li
- Department of Endocrinology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei. China
| | - Yan Yang
- Department of Endocrinology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei. China
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Micioni Di Bonaventura E, Botticelli L, Del Bello F, Giorgioni G, Piergentili A, Quaglia W, Cifani C, Micioni Di Bonaventura MV. Assessing the role of ghrelin and the enzyme ghrelin O-acyltransferase (GOAT) system in food reward, food motivation, and binge eating behavior. Pharmacol Res 2021; 172:105847. [PMID: 34438062 DOI: 10.1016/j.phrs.2021.105847] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 08/19/2021] [Accepted: 08/20/2021] [Indexed: 02/06/2023]
Abstract
The peripheral peptide hormone ghrelin is a powerful stimulator of food intake, which leads to body weight gain and adiposity in both rodents and humans. The hormone, thus, increases the vulnerability to obesity and binge eating behavior. Several studies have revealed that ghrelin's functions are due to its interaction with the growth hormone secretagogue receptor type 1a (GHSR1a) in the hypothalamic area; besides, ghrelin also promotes the reinforcing properties of hedonic food, acting at extra-hypothalamic sites and interacting with dopaminergic, cannabinoid, opioid, and orexin signaling. The hormone is primarily present in two forms in the plasma and the enzyme ghrelin O-acyltransferase (GOAT) allows the acylation reaction which causes the transformation of des-acyl-ghrelin (DAG) to the active form acyl-ghrelin (AG). DAG has been demonstrated to show antagonist properties; it is metabolically active, and counteracts the effects of AG on glucose metabolism and lipolysis, and reduces food consumption, body weight, and hedonic feeding response. Both peptides seem to influence the hypothalamic-pituitary-adrenal (HPA) axis and the corticosterone/cortisol level that drive the urge to eat under stressful conditions. These findings suggest that DAG and inhibition of GOAT may be targets for obesity and bingeing-related eating disorders and that AG/DAG ratio may be an important potential biomarker to assess the risk of developing maladaptive eating behaviors.
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Affiliation(s)
| | - Luca Botticelli
- School of Pharmacy, Pharmacology Unit, University of Camerino, via Madonna delle Carceri, 9, 62032 Camerino, Italy
| | - Fabio Del Bello
- School of Pharmacy, Medicinal Chemistry Unit, University of Camerino, via S. Agostino, 1, 62032 Camerino, Italy
| | - Gianfabio Giorgioni
- School of Pharmacy, Medicinal Chemistry Unit, University of Camerino, via S. Agostino, 1, 62032 Camerino, Italy
| | - Alessandro Piergentili
- School of Pharmacy, Medicinal Chemistry Unit, University of Camerino, via S. Agostino, 1, 62032 Camerino, Italy
| | - Wilma Quaglia
- School of Pharmacy, Medicinal Chemistry Unit, University of Camerino, via S. Agostino, 1, 62032 Camerino, Italy
| | - Carlo Cifani
- School of Pharmacy, Pharmacology Unit, University of Camerino, via Madonna delle Carceri, 9, 62032 Camerino, Italy.
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Wang M, Yoon G, Song J, Jo J. Exendin-4 improves long-term potentiation and neuronal dendritic growth in vivo and in vitro obesity condition. Sci Rep 2021; 11:8326. [PMID: 33859286 PMCID: PMC8050263 DOI: 10.1038/s41598-021-87809-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 03/30/2021] [Indexed: 12/13/2022] Open
Abstract
Metabolic syndrome, which increases the risk of obesity and type 2 diabetes has emerged as a significant issue worldwide. Recent studies have highlighted the relationship between metabolic imbalance and neurological pathologies such as memory loss. Glucagon-like peptide 1 (GLP-1) secreted from gut L-cells and specific brain nuclei plays multiple roles including regulation of insulin sensitivity, inflammation and synaptic plasticity. Although GLP-1 and GLP-1 receptor agonists appear to have neuroprotective function, the specific mechanism of their action in brain remains unclear. We investigated whether exendin-4, as a GLP-1RA, improves cognitive function and brain insulin resistance in metabolic-imbalanced mice fed a high-fat diet. Considering the result of electrophysiological experiments, exendin-4 inhibits the reduction of long term potentiation (LTP) in high fat diet mouse brain. Further, we identified the neuroprotective effect of exendin-4 in primary cultured hippocampal and cortical neurons in in vitro metabolic imbalanced condition. Our results showed the improvement of IRS-1 phosphorylation, neuronal complexity, and the mature of dendritic spine shape by exendin-4 treatment in metabolic imbalanced in vitro condition. Here, we provides significant evidences on the effect of exendin-4 on synaptic plasticity, long-term potentiation, and neural structure. We suggest that GLP-1 is important to treat neuropathology caused by metabolic syndrome.
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Affiliation(s)
- Ming Wang
- BioMedical Sciences Graduate Program (BMSGP), Chonnam National University, 264 seoyangro, Hwasun, 58128, Republic of Korea
| | - Gwangho Yoon
- BioMedical Sciences Graduate Program (BMSGP), Chonnam National University, 264 seoyangro, Hwasun, 58128, Republic of Korea.,Department of Anatomy, Chonnam National University Medical School, Hwasun, Jeollanam-do, 58128, Republic of Korea
| | - Juhyun Song
- BioMedical Sciences Graduate Program (BMSGP), Chonnam National University, 264 seoyangro, Hwasun, 58128, Republic of Korea. .,Department of Anatomy, Chonnam National University Medical School, Hwasun, Jeollanam-do, 58128, Republic of Korea.
| | - Jihoon Jo
- BioMedical Sciences Graduate Program (BMSGP), Chonnam National University, 264 seoyangro, Hwasun, 58128, Republic of Korea. .,NeuroMedical Convergence Lab, Biomedical Research Institute, Chonnam National University Hospital, Jebong-ro, Gwangju, 501-757, Republic of Korea. .,Department of Neurology, Chonnam National University Medical School, Gwangju, 501-757, Republic of Korea.
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9
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Rahman MH, Bhusal A, Kim JH, Jha MK, Song GJ, Go Y, Jang IS, Lee IK, Suk K. Astrocytic pyruvate dehydrogenase kinase-2 is involved in hypothalamic inflammation in mouse models of diabetes. Nat Commun 2020; 11:5906. [PMID: 33219201 PMCID: PMC7680139 DOI: 10.1038/s41467-020-19576-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 10/22/2020] [Indexed: 02/07/2023] Open
Abstract
Hypothalamic inflammation plays an important role in disrupting feeding behavior and energy homeostasis as well as in the pathogenesis of obesity and diabetes. Here, we show that pyruvate dehydrogenase kinase (PDK)-2 plays a role in hypothalamic inflammation and its sequelae in mouse models of diabetes. Cell type-specific genetic ablation and pharmacological inhibition of PDK2 in hypothalamic astrocytes suggest that hypothalamic astrocytes are involved in the diabetic phenotype. We also show that the PDK2-lactic acid axis plays a regulatory role in the observed metabolic imbalance and hypothalamic inflammation in mouse primary astrocyte and organotypic cultures, through the AMPK signaling pathway and neuropeptidergic circuitry governing feeding behavior. Our findings reveal that PDK2 ablation or inhibition in mouse astrocytes attenuates diabetes-induced hypothalamic inflammation and subsequent alterations in feeding behavior. Hypothalamic inflammation is involved in the pathogenesis of diabetes. The underlying mechanisms are unclear. Here, the authors show that astrocytic PDK2 ablation or inhibition attenuates hypothalamic inflammation in mouse models of diabetes.
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Affiliation(s)
- Md Habibur Rahman
- BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Science and Department of Pharmacology, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Anup Bhusal
- BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Science and Department of Pharmacology, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Jae-Hong Kim
- BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Science and Department of Pharmacology, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Mithilesh Kumar Jha
- Department of Neurology, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Gyun Jee Song
- Department of Medical Science, College of Medicine, Catholic Kwandong University, Gangneung-si, Republic of Korea.,Translational Brain Research Center, International St. Mary's Hospital, Catholic Kwandong University, Incheon, Republic of Korea
| | - Younghoon Go
- Korean Medicine Application Center, Korea Institute of Oriental Medicine, Daegu, 41062, Republic of Korea
| | - Il-Sung Jang
- Department of Pharmacology, School of Dentistry, Kyungpook National University, Daegu, 700-412, Republic of Korea.,Brain Science and Engineering Institute, Kyungpook National University, Daegu, 41944, Republic of Korea
| | - In-Kyu Lee
- Department of Internal Medicine, School of Medicine, Kyungpook National University Hospital, Daegu, 700-721, Republic of Korea.,Research Institute of Aging and Metabolism, Kyungpook National University, Daegu, 700-721, Republic of Korea
| | - Kyoungho Suk
- BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Science and Department of Pharmacology, School of Medicine, Kyungpook National University, Daegu, Republic of Korea. .,Brain Science and Engineering Institute, Kyungpook National University, Daegu, 41944, Republic of Korea.
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10
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McCarthy SF, Islam H, Hazell TJ. The emerging role of lactate as a mediator of exercise-induced appetite suppression. Am J Physiol Endocrinol Metab 2020; 319:E814-E819. [PMID: 32893673 DOI: 10.1152/ajpendo.00256.2020] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Lactate, a molecule originally considered metabolic waste, is now associated with a number of important physiological functions. Although the roles of lactate as a signaling molecule, fuel source, and gluconeogenic substrate have garnered significant attention in recent reviews, a relatively underexplored and emerging role of lactate is its control of energy intake (EI). To expand our understanding of the physiological roles of lactate, we present evidence from early infusion studies demonstrating the ability of lactate to suppress EI in both rodents and humans. We then discuss findings from recent human studies that have utilized exercise intensity and/or sodium bicarbonate supplementation to modulate endogenous lactate and examine its impact on appetite regulation. These studies consistently demonstrate that greater blood lactate accumulation is associated with greater suppression of the hunger hormone ghrelin and subjective appetite, thereby supporting a role of lactate in the control of EI. To stimulate future research investigating the role of lactate as an appetite-regulatory molecule, we also highlight potential underlying mechanisms explaining the appetite-suppressive effects of lactate using evidence from rodent and in vitro cellular models. Specifically, we discuss the ability of lactate to 1) inhibit the secretory function of ghrelin producing gastric cells, 2) modulate the signaling cascades that control hypothalamic neuropeptide expression/release, and 3) inhibit signaling through the ghrelin receptor in the hypothalamus. Unravelling the role of lactate as an appetite-regulatory molecule can shed important insight into the regulation of EI, thereby contributing to the development of interventions aimed at combatting overweight and obesity.
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Affiliation(s)
- Seth F McCarthy
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, Waterloo, Ontario, Canada
| | - Hashim Islam
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Tom J Hazell
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, Waterloo, Ontario, Canada
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11
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A GPR17-cAMP-Lactate Signaling Axis in Oligodendrocytes Regulates Whole-Body Metabolism. Cell Rep 2020; 26:2984-2997.e4. [PMID: 30865888 PMCID: PMC6679936 DOI: 10.1016/j.celrep.2019.02.060] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 02/02/2019] [Accepted: 02/14/2019] [Indexed: 12/20/2022] Open
Abstract
The CNS plays a pivotal role in energy homeostasis, but whether oligodendrocytes are involved has been largely unexplored. Here, we show that signaling through GPR17, a G-protein-coupled receptor predominantly expressed in the oligodendrocyte lineage, regulates food intake by modulating hypothalamic neuronal activities. GPR17-null mice and mice with an oligodendrocyte-specific knockout of GPR17 have lean phenotypes on a high-fat diet, suggesting that GPR17 regulates body weight by way of oligodendrocytes. Downregulation of GPR17 results in activation of cAMP-protein kinase A (PKA) signaling in oligodendrocytes and upregulated expression of pyruvate dehydrogenase kinase 1 (PDK1), which promotes lactate production. Elevation of lactate activates AKT and STAT3 signaling in the hypothalamic neurons, leading to increased expression of Pomc and suppression of Agrp. Our findings uncover a critical role of oligodendrocytes in metabolic homeostasis, where GPR17 modulates the production of lactate, which, in turn, acts as a metabolic signal to regulate neuronal activity.
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12
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Shen X, Luo L, Yang M, Lin Y, Li J, Yang L. Exendin‑4 inhibits lipotoxicity‑induced oxidative stress in β‑cells by inhibiting the activation of TLR4/NF‑κB signaling pathway. Int J Mol Med 2020; 45:1237-1249. [PMID: 32124969 DOI: 10.3892/ijmm.2020.4490] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 12/02/2019] [Indexed: 11/05/2022] Open
Abstract
The present study aimed to investigate the relationship between the protective effects of exendin‑4 (EX‑4) on lipotoxicity‑induced oxidative stress and meta‑inflammation in β‑cells and the toll‑like receptor 4 (TLR4)/NF‑κB signaling pathway. Lipotoxicity, hydrogen peroxide (H2O2)‑induced oxidative stress in β cells, obese Sprague Dawley rats and TLR4 truncation rats were utilized in the present study. The expression levels were detected by western blotting; cell apoptosis was detected by TUNEL assay; and the intracellular reactive oxygen species (ROS) levels were analyzed using a ROS assay kit. The findings of the present study showed that EX‑4 inhibited the expression of TLR4, NF‑κB p65 subunit and p47phox in a concentration‑dependent manner, and decreased the intracellular level of ROS. Additionally, silencing of TLR4 expression enhanced the protective effects of EX‑4, while overexpression of TLR4 attenuated these protective influences. Simultaneously, it was demonstrated that TLR4 was involved in the process of EX‑4 intervention to inhibit H2O2‑induced oxidative stress in islet β‑cells. Moreover, it was found that EX‑4 also inhibited TLR4‑ or NF‑κB agonist‑induced oxidative stress. These results were also confirmed in an animal model of obese rats, in which EX‑4 was able to improve the function of β‑cells, attenuate oxidative stress, and inhibit the expression levels of TLR4 and NF‑κB p65 subunit in the pancreas of the diet‑induced obese rats. Furthermore, truncation of the TLR4 gene in SD rats delayed the aforementioned damage. In summary, EX‑4 may inhibit lipotoxicity‑induced oxidative stress in β‑cells by inhibiting the activation of the TLR4/NF‑κB signaling pathway.
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Affiliation(s)
- Ximei Shen
- Endocrinology Department, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350005, P.R. China
| | - Liufen Luo
- Endocrinology Department, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350005, P.R. China
| | - Meng Yang
- Endocrinology Department, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350005, P.R. China
| | - Yuxi Lin
- Endocrinology Department, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350005, P.R. China
| | - Jing Li
- Endocrinology Department, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350005, P.R. China
| | - Liyong Yang
- Endocrinology Department, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350005, P.R. China
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13
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Glotfelty EJ, Delgado TE, Tovar-y-Romo LB, Luo Y, Hoffer BJ, Olson L, Karlsson TE, Mattson MP, Harvey BK, Tweedie D, Li Y, Greig NH. Incretin Mimetics as Rational Candidates for the Treatment of Traumatic Brain Injury. ACS Pharmacol Transl Sci 2019; 2:66-91. [PMID: 31396586 PMCID: PMC6687335 DOI: 10.1021/acsptsci.9b00003] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Indexed: 12/17/2022]
Abstract
Traumatic brain injury (TBI) is becoming an increasing public health issue. With an annually estimated 1.7 million TBIs in the United States (U.S) and nearly 70 million worldwide, the injury, isolated or compounded with others, is a major cause of short- and long-term disability and mortality. This, along with no specific treatment, has made exploration of TBI therapies a priority of the health system. Age and sex differences create a spectrum of vulnerability to TBI, with highest prevalence among younger and older populations. Increased public interest in the long-term effects and prevention of TBI have recently reached peaks, with media attention bringing heightened awareness to sport and war related head injuries. Along with short-term issues, TBI can increase the likelihood for development of long-term neurodegenerative disorders. A growing body of literature supports the use of glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic peptide (GIP), and glucagon (Gcg) receptor (R) agonists, along with unimolecular combinations of these therapies, for their potent neurotrophic/neuroprotective activities across a variety of cellular and animal models of chronic neurodegenerative diseases (Alzheimer's and Parkinson's diseases) and acute cerebrovascular disorders (stroke). Mild or moderate TBI shares many of the hallmarks of these conditions; recent work provides evidence that use of these compounds is an effective strategy for its treatment. Safety and efficacy of many incretin-based therapies (GLP-1 and GIP) have been demonstrated in humans for the treatment of type 2 diabetes mellitus (T2DM), making these compounds ideal for rapid evaluation in clinical trials of mild and moderate TBI.
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Affiliation(s)
- Elliot J. Glotfelty
- Translational
Gerontology Branch, and Laboratory of Neurosciences, Intramural
Research Program, National Institute on
Aging, National Institutes of Health, Baltimore, Maryland 21224, United States
- Department
of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Thomas E. Delgado
- Translational
Gerontology Branch, and Laboratory of Neurosciences, Intramural
Research Program, National Institute on
Aging, National Institutes of Health, Baltimore, Maryland 21224, United States
| | - Luis B. Tovar-y-Romo
- Division
of Neuroscience, Institute of Cellular Physiology, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Yu Luo
- Department
of Molecular Genetics, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Barry J. Hoffer
- Department
of Neurosurgery, Case Western Reserve University
School of Medicine, Cleveland, Ohio 44106, United States
| | - Lars Olson
- Department
of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | | | - Mark P. Mattson
- Translational
Gerontology Branch, and Laboratory of Neurosciences, Intramural
Research Program, National Institute on
Aging, National Institutes of Health, Baltimore, Maryland 21224, United States
| | - Brandon K. Harvey
- Molecular
Mechanisms of Cellular Stress and Inflammation Unit, Integrative Neuroscience
Department, National Institute on Drug Abuse,
National Institutes of Health, Baltimore, Maryland 21224, United States
| | - David Tweedie
- Translational
Gerontology Branch, and Laboratory of Neurosciences, Intramural
Research Program, National Institute on
Aging, National Institutes of Health, Baltimore, Maryland 21224, United States
| | - Yazhou Li
- Translational
Gerontology Branch, and Laboratory of Neurosciences, Intramural
Research Program, National Institute on
Aging, National Institutes of Health, Baltimore, Maryland 21224, United States
| | - Nigel H. Greig
- Translational
Gerontology Branch, and Laboratory of Neurosciences, Intramural
Research Program, National Institute on
Aging, National Institutes of Health, Baltimore, Maryland 21224, United States
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14
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Lyra E Silva NDM, Gonçalves RA, Boehnke SE, Forny-Germano L, Munoz DP, De Felice FG. Understanding the link between insulin resistance and Alzheimer's disease: Insights from animal models. Exp Neurol 2019; 316:1-11. [PMID: 30930096 DOI: 10.1016/j.expneurol.2019.03.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 03/22/2019] [Accepted: 03/26/2019] [Indexed: 12/14/2022]
Abstract
Alzheimer's disease (AD) is a devastating neurodegenerative disease affecting millions of people worldwide. AD is characterized by a profound impairment of higher cognitive functions and still lacks any effective disease-modifying treatment. Defective insulin signaling has been implicated in AD pathophysiology, but the mechanisms underlying this process are not fully understood. Here, we review the molecular mechanisms underlying defective brain insulin signaling in rodent models of AD, and in a non-human primate (NHP) model of the disease that recapitulates features observed in AD brains. We further highlight similarities between the NHP and human brains and discuss why NHP models of AD are important to understand disease mechanisms and to improve the translation of effective therapies to humans. We discuss how studies using different animal models have contributed to elucidate the link between insulin resistance and AD.
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Affiliation(s)
| | | | - Susan E Boehnke
- Centre for Neuroscience Studies, Queen's University, Kingston, ON, Canada
| | - Leticia Forny-Germano
- Institute of Medical Biochemistry Leopoldo De Meis, Federal University of Rio de Janeiro, Brazil
| | - Douglas P Munoz
- Centre for Neuroscience Studies, Queen's University, Kingston, ON, Canada.
| | - Fernanda G De Felice
- Centre for Neuroscience Studies, Queen's University, Kingston, ON, Canada; Department of Psychiatry, Queen's University, Kingston, ON, Canada; Institute of Medical Biochemistry Leopoldo De Meis, Federal University of Rio de Janeiro, Brazil.
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15
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Tao L, Wang L, Yang X, Jiang X, Hua F. Recombinant human glucagon-like peptide-1 protects against chronic intermittent hypoxia by improving myocardial energy metabolism and mitochondrial biogenesis. Mol Cell Endocrinol 2019; 481:95-103. [PMID: 30503377 DOI: 10.1016/j.mce.2018.11.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Revised: 11/26/2018] [Accepted: 11/27/2018] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND AIMS Obstructive sleep apnea syndrome is a chronic disease associated with intermittent hypoxia (IH) and is an important risk factor for cardiovascular disease. Glucagon-like peptide (GLP-1) is a naturally occurring incretin used as a promising therapeutic agent in the treatment of acute myocardial infarction, dilated cardiomyopathy, and advanced heart failure. However, whether GLP-1 can protect against IH-induced cardiac injury is still unclear. Accordingly, in this study, we evaluated the effects of recombinant human GLP-1 (rhGLP-1) on cardiac health in mice. METHODS Mice were subjected to repetitive 5% O2 for 30 s and 21% O2 for 30 s, for a total of 8 h/day for 4 weeks. Subsequently, mice received subcutaneous injection of saline or rhGLP-1 (100 μg/kg, three times per day). Cardiac function, myocardial apoptosis and fibrosis, energy metabolism, and mitochondrial biogenesis were examined for evaluation of cardiac injury. RESULTS A reduction in diastolic function (E/A ratio) in mice exposed to IH was significantly reversed by rhGLP-1. IH induced marked cardiomyocyte apoptosis and myocardial fibrosis. Additionally, IH resulted in a shift from fatty acid to glucose metabolism in the myocardium with downregulation of peroxisome proliferator-activated receptor (PPAR) α and PPARγ. Moreover, IH caused a reduction in mitochondrial DNA (mtDNA) replication and transcription, together with reduced mtDNA content and impaired mitochondrial ultrastructure. These changes were abolished by rhGLP-1 via activation of PGC-1α and Akt signaling. CONCLUSIONS rhGLP-1 protects against IH-induced cardiac injury by improving myocardial energy metabolism and enhancing the early adaptive changes of mitochondrial biogenesis.
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Affiliation(s)
- Lichan Tao
- Department of Cardiology, The Third Affiliated Hospital of Soochow University, Changzhou City, 213003, China
| | - Long Wang
- Department of Endocrinology, The Third Affiliated Hospital of Soochow University, Changzhou City, 213003, China
| | - Xiaoyu Yang
- Department of Cardiology, The Third Affiliated Hospital of Soochow University, Changzhou City, 213003, China
| | - Xiaohong Jiang
- Department of Endocrinology, The Third Affiliated Hospital of Soochow University, Changzhou City, 213003, China
| | - Fei Hua
- Department of Endocrinology, The Third Affiliated Hospital of Soochow University, Changzhou City, 213003, China.
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16
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Nie XG, Fan DS, Huang YX, He YY, Dong BL, Gao F. Downregulation of microRNA-149 in retinal ganglion cells suppresses apoptosis through activation of the PI3K/Akt signaling pathway in mice with glaucoma. Am J Physiol Cell Physiol 2018; 315:C839-C849. [PMID: 30183321 DOI: 10.1152/ajpcell.00324.2017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Glaucoma represents a major cause of blindness, generally associated with elevated intraocular pressure (EIOP). The aim of the present study was to investigate whether microRNA-149 (miR-149) affects retinal ganglion cells (RGCs) and the underlying mechanism based on a mouse model of chronic glaucoma with EIOP. The successfully modeled mice were administered with mimics or inhibitors of miR-149. Next, the number of RGCs, ultrastructural changes of RGCs, and purity of RGCs in the retinal tissues were detected. Moreover, the RGCs were collected and subsequently treated with 60 mmHg pressure and transfected with a series of plasmids aiding in the regulation of the expression of miR-149 and betacellulin (BTC). The levels of miR-149, BTC, phosphatidylinositol 3-kinase (PI3K), and Akt were subsequently determined. Finally, RGC viability and apoptosis were detected accordingly. Dual luciferase reporter gene assay provided validation, highlighting BTC was indeed a target gene of miR-149. The downregulation of miR-149 is accompanied by an increased number of RGCs and decreased ultrastructural RGC alterations. Additionally, downregulated miR-149 was noted to increase the levels of BTC, PI3K, and Akt in both the retinal tissues and RGCs, whereas the silencing of miR-149 was observed to promote the viability of RGC and inhibit RGC apoptosis. Taken together, the results of the current study provided validation suggesting that the downregulation of miR-149 confers protection to RGCs by means of activating the PI3K/Akt signaling pathway via upregulation of BTC in mice with glaucoma. Evidence presented indicated the promise of miR-149 inhibition as a potential therapeutic strategy for glaucoma treatment.
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Affiliation(s)
- Xin-Gang Nie
- Department of Ophthalmology, Luoyang Central Hospital , Luoyang , People's Republic of China
| | - Dong-Sheng Fan
- Department of Ophthalmology, Luoyang Central Hospital , Luoyang , People's Republic of China
| | - Yan-Xia Huang
- Department of Ophthalmology, Luoyang Central Hospital , Luoyang , People's Republic of China
| | - Ying-Ying He
- Department of Ophthalmology, Luoyang Central Hospital , Luoyang , People's Republic of China
| | - Bo-Li Dong
- Department of Ophthalmology, Luoyang Central Hospital , Luoyang , People's Republic of China
| | - Feng Gao
- Department of Ophthalmology, Luoyang Central Hospital , Luoyang , People's Republic of China
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17
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Brown JD, McAnally D, Ayala JE, Burmeister MA, Morfa C, Smith L, Ayala JE. Oleoylethanolamide modulates glucagon-like peptide-1 receptor agonist signaling and enhances exendin-4-mediated weight loss in obese mice. Am J Physiol Regul Integr Comp Physiol 2018; 315:R595-R608. [PMID: 29949410 DOI: 10.1152/ajpregu.00459.2017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Long-acting glucagon-like peptide-1 (GLP-1) receptor (GLP-1R) agonists (GLP-1RA), such as exendin-4 (Ex4), promote weight loss. On the basis of a newly discovered interaction between GLP-1 and oleoylethanolamide (OEA), we tested whether OEA enhances GLP-1RA-mediated anorectic signaling and weight loss. We analyzed the effect of GLP-1+OEA and Ex4+OEA on canonical GLP-1R signaling and other proteins/pathways that contribute to the hypophagic action of GLP-1RA (AMPK, Akt, mTOR, and glycolysis). We demonstrate that OEA enhances canonical GLP-1R signaling when combined with GLP-1 but not with Ex4. GLP-1 and Ex4 promote phosphorylation of mTOR pathway components, but OEA does not enhance this effect. OEA synergistically enhanced GLP-1- and Ex4-stimulated glycolysis but did not augment the hypophagic action of GLP-1 or Ex4 in lean or diet-induced obese (DIO) mice. However, the combination of Ex4+OEA promoted greater weight loss in DIO mice than Ex4 or OEA alone during a 7-day treatment. This was due in part to transient hypophagia and increased energy expenditure, phenotypes also observed in Ex4-treated DIO mice. Thus, OEA augments specific GLP-1RA-stimulated signaling but appears to work in parallel with Ex4 to promote weight loss in DIO mice. Elucidating cooperative mechanisms underlying Ex4+OEA-mediated weight loss could, therefore, be leveraged toward more effective obesity therapies.
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Affiliation(s)
- Jacob D Brown
- Integrative Metabolism Program, Sanford Burnham Prebys Medical Discovery Institute at Lake Nona , Orlando, Florida
| | - Danielle McAnally
- Cardiovascular Metabolism Program, Sanford Burnham Prebys Medical Discovery Institute at Lake Nona , Orlando, Florida
| | - Jennifer E Ayala
- Integrative Metabolism Program, Sanford Burnham Prebys Medical Discovery Institute at Lake Nona , Orlando, Florida
| | - Melissa A Burmeister
- Integrative Metabolism Program, Sanford Burnham Prebys Medical Discovery Institute at Lake Nona , Orlando, Florida
| | - Camilo Morfa
- Cardiovascular Metabolism Program, Sanford Burnham Prebys Medical Discovery Institute at Lake Nona , Orlando, Florida
| | - Layton Smith
- Cardiovascular Metabolism Program, Sanford Burnham Prebys Medical Discovery Institute at Lake Nona , Orlando, Florida
| | - Julio E Ayala
- Integrative Metabolism Program, Sanford Burnham Prebys Medical Discovery Institute at Lake Nona , Orlando, Florida
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