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Wang Y, Kulkarni VV, Pantaleón García J, Leiva-Juárez MM, Goldblatt DL, Gulraiz F, Chen J, Donepudi SR, Lorenzi PL, Wang H, Wong LJ, Tuvim MJ, Evans SE. Antimicrobial mitochondrial reactive oxygen species induction by lung epithelial metabolic reprogramming. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.19.524841. [PMID: 36711510 PMCID: PMC9882263 DOI: 10.1101/2023.01.19.524841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Pneumonia is a worldwide threat, making discovery of novel means to combat lower respiratory tract infections an urgent need. We have previously shown that manipulating the lungs' intrinsic host defenses by therapeutic delivery of a unique dyad of pathogen-associated molecular patterns protects mice against pneumonia in a reactive oxygen species (ROS)-dependent manner. Here we show that antimicrobial ROS are induced from lung epithelial cells by interactions of CpG oligodeoxynucleotides (ODNs) with mitochondrial voltage-dependent anion channel 1 (VDAC1) without dependence on Toll-like receptor 9 (TLR9). The ODN-VDAC1 interaction alters cellular ATP/ADP/AMP localization, increases delivery of electrons to the electron transport chain (ETC), enhances mitochondrial membrane potential (Δ Ψm ), and differentially modulates ETC complex activities. These combined effects promote leak of electrons from ETC complex III, resulting in superoxide formation. The ODN-induced mitochondrial ROS yield protective antibacterial effects. Together, these studies identify a therapeutic metabolic manipulation strategy that has the potential to broadly protect patients against pneumonia during periods of peak vulnerability without reliance on currently available antibiotics. Author Summary Pneumonia is a major cause of death worldwide. Increasing antibiotic resistance and expanding immunocompromised populations continue to enhance the clinical urgency to find new strategies to prevent and treat pneumonia. We have identified a novel inhaled therapeutic that stimulates lung epithelial defenses to protect mice against pneumonia in a manner that depends on production of reactive oxygen species (ROS). Here, we report that the induction of protective ROS from lung epithelial mitochondria occurs following the interaction of one component of the treatment, an oligodeoxynucleotide, with the mitochondrial voltage-dependent anion channel 1. This interaction alters energy transfer between the mitochondria and the cytosol, resulting in metabolic reprogramming that drives more electrons into the electron transport chain, then causes electrons to leak from the electron transport chain to form protective ROS. While antioxidant therapies are endorsed in many other disease states, we present here an example of therapeutic induction of ROS that is associated with broad protection against pneumonia without reliance on administration of antibiotics.
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Affiliation(s)
- Yongxing Wang
- Department of Pulmonary Medicine, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Vikram V. Kulkarni
- Department of Pulmonary Medicine, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, Texas, USA
| | - Jezreel Pantaleón García
- Department of Pulmonary Medicine, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Miguel M. Leiva-Juárez
- Department of Pulmonary Medicine, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - David L. Goldblatt
- Department of Pulmonary Medicine, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Fahad Gulraiz
- Department of Pulmonary Medicine, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Jichao Chen
- Department of Pulmonary Medicine, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Sri Ramya Donepudi
- University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, Texas, USA
| | - Philip L. Lorenzi
- University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, Texas, USA
| | - Hao Wang
- Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Lee-Jun Wong
- Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Michael J. Tuvim
- Department of Pulmonary Medicine, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Scott E. Evans
- Department of Pulmonary Medicine, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, Texas, USA
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Hernández-Saavedra D, Stanford KI. The Regulation of Lipokines by Environmental Factors. Nutrients 2019; 11:E2422. [PMID: 31614481 PMCID: PMC6835582 DOI: 10.3390/nu11102422] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 10/06/2019] [Accepted: 10/09/2019] [Indexed: 01/08/2023] Open
Abstract
Adipose tissue is a highly metabolically-active tissue that senses and secretes hormonal and lipid mediators that facilitate adaptations to metabolic tissues. In recent years, the role of lipokines, which are lipid species predominantly secreted from adipose tissue that act as hormonal regulators in many metabolic tissues, has been an important area of research for obesity and diabetes. Previous studies have identified that these secreted lipids, including palmitoleate, 12,13-diHOME, and fatty acid-hydroxy-fatty acids (FAHFA) species, are important regulators of metabolism. Moreover, environmental factors that directly affect the secretion of lipokines such as diet, exercise, and exposure to cold temperatures constitute attractive therapeutic strategies, but the mechanisms that regulate lipokine stimulation have not been thoroughly reviewed. In this study, we will discuss the chemical characteristics of lipokines that position them as attractive targets for chronic disease treatment and prevention and the emerging roles of lipokines as regulators of inter-tissue communication. We will define the target tissues of lipokines, and explore the ability of lipokines to prevent or delay the onset and development of chronic diseases. Comprehensive understanding of the lipokine synthesis and lipokine-driven regulation of metabolic outcomes is instrumental for developing novel preventative and therapeutic strategies that harness adipose tissue-derived lipokines.
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Affiliation(s)
- Diego Hernández-Saavedra
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA.
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA.
| | - Kristin I Stanford
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA.
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA.
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3
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Mika A, Macaluso F, Barone R, Di Felice V, Sledzinski T. Effect of Exercise on Fatty Acid Metabolism and Adipokine Secretion in Adipose Tissue. Front Physiol 2019; 10:26. [PMID: 30745881 PMCID: PMC6360148 DOI: 10.3389/fphys.2019.00026] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 01/11/2019] [Indexed: 12/19/2022] Open
Abstract
Increased physical activity is an optimal way to maintain a good health. During exercise, triacylglycerols, an energy reservoir in adipose tissue, are hydrolyzed to free fatty acids (FAs) which are then released to the circulation, providing a fuel for working muscles. Thus, regular physical activity leads to a reduction of adipose tissue mass and improves metabolism. However, the reduction of lipid reservoir is also associated with many other interesting changes in adipose tissue FA metabolism. For example, a prolonged exercise contributes to a decrease in lipoprotein lipase activity and resultant reduction of FA uptake. This results in the improvement of mitochondrial function and upregulation of enzymes involved in the metabolism of polyunsaturated fatty acids. The exercise-induced changes in adipocyte metabolism are associated with modifications of FA composition. The modifications are adipose tissue depot-specific and follow different patterns in visceral and subcutaneous adipose tissue. Moreover, exercise affects adipokine release from adipose tissue, and thus, may mitigate inflammation and improve insulin sensitivity. Another consequence of exercise is the recently described phenomenon of adipose tissue “beiging,” i.e., a switch from energy-storing white adipocyte phenotype to thermogenic FA oxidizing beige adipocytes. This process is regulated by myokines released during the exercise. In this review, we summarize published evidence for the exercise-related changes in FA metabolism and adipokine release in adipose tissue, and their potential contribution to beneficial cardiovascular and metabolic effects of physical activity.
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Affiliation(s)
- Adriana Mika
- Department of Pharmaceutical Biochemistry, Faculty of Pharmacy, Medical University of Gdańsk, Gdańsk, Poland.,Department of Environmental Analysis, Faculty of Chemistry, University of Gdańsk, Gdańsk, Poland
| | - Filippo Macaluso
- Department of Biomedicine, Neurosciences, and Advanced Diagnostic (Bi.N.D.), University of Palermo, Palermo, Italy.,Euro-Mediterranean Institute of Science and Technology, Palermo, Italy.,SMART Engineering Solutions & Technologies (SMARTEST) Research Center, eCampus University, Palermo, Italy
| | - Rosario Barone
- Department of Biomedicine, Neurosciences, and Advanced Diagnostic (Bi.N.D.), University of Palermo, Palermo, Italy.,Euro-Mediterranean Institute of Science and Technology, Palermo, Italy
| | - Valentina Di Felice
- Department of Biomedicine, Neurosciences, and Advanced Diagnostic (Bi.N.D.), University of Palermo, Palermo, Italy.,Euro-Mediterranean Institute of Science and Technology, Palermo, Italy
| | - Tomasz Sledzinski
- Department of Pharmaceutical Biochemistry, Faculty of Pharmacy, Medical University of Gdańsk, Gdańsk, Poland
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Liu KL, Kuo WC, Lin CY, Lii CK, Liu YL, Cheng YH, Tsai CW. Prevention of 4-hydroxynonenal-induced lipolytic activation by carnosic acid is related to the induction of glutathione S-transferase in 3T3-L1 adipocytes. Free Radic Biol Med 2018; 121:1-8. [PMID: 29698741 DOI: 10.1016/j.freeradbiomed.2018.04.567] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 04/12/2018] [Accepted: 04/21/2018] [Indexed: 02/07/2023]
Abstract
UNLABELLED Induction of 4-hydroxynonenal (4-HNE), a major lipid peroxidation aldehyde, is observed in patients with obesity and type 2 diabetes mellitus. The lipolytic response by 4-HNE has been linked to insulin resistance. In this study, we investigated the effects of carnosic acid (CA) on 4-HNE-induced lipolysis and the inhibition of β-oxidation in 3T3-L1 adipocytes. The results indicated that cells pretreated with CA reduced 4-HNE-mediated free fatty acid (FFA) release. Furthermore, CA reversed the inhibition of phosphorylation of Tyr632 of insulin receptor substrate-1 (IRS-1) and Akt and the phosphorylation of Ser307 of IRS-1. CA inhibited 4-HNE-induced phosphorylation of protein kinase A (PKA) and hormone-sensitive lipase (HSL), and reversed the suppression by 4-HNE of phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (p < 0.05). Pretreatment of cells with forskolin (a cAMP agonist) and compound C (an AMPK inhibitor) reversed these effects, respectively (p < 0.05). In human subcutaneous adipocytes, CA also attenuated 4-HNE-induced FFA release and the phosphorylation of PKA and HSL (p < 0.05). Moreover, CA increased the protein expression of glutathione S-transferase (GST) A and M. Pretreatment with ethacrynic acid, a GST inhibitor, prevented the 4-HNE-conjugated proteins suppression, the PKA and HSL phosphorylation reduction, and the FFA release inhibition by CA (p < 0.05). CONCLUSION The attenuation by CA of the lipolytic response by 4-HNE is likely related to the induction of GST, which in turn reduced 4-HNE-conjugated proteins and decreased the activation of the PKA/HSL pathway. The observed effects may explain how CA improves 4-HNE-induced insulin resistance.
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Affiliation(s)
- Kai-Li Liu
- Department of Nutrition, Chung Shan Medical University, Taichung, Taiwan; Department of Dietitian, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Wen-Chen Kuo
- Department of Nutrition, China Medical University, Taichung, Taiwan
| | - Chia-Yuan Lin
- Department of Nutrition, China Medical University, Taichung, Taiwan
| | - Chong-Kuei Lii
- Department of Nutrition, China Medical University, Taichung, Taiwan
| | - Yen-Lin Liu
- Department of Nutrition, China Medical University, Taichung, Taiwan
| | - Yun-Hsin Cheng
- Department of Nutrition, China Medical University, Taichung, Taiwan
| | - Chia-Wen Tsai
- Department of Nutrition, China Medical University, Taichung, Taiwan.
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5
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Gao D, Zhang YL, Yang FQ, Li F, Zhang QH, Xia ZN. The flower of Edgeworthia gardneri (wall.) Meisn. suppresses adipogenesis through modulation of the AMPK pathway in 3T3-L1 adipocytes. JOURNAL OF ETHNOPHARMACOLOGY 2016; 191:379-386. [PMID: 27350007 DOI: 10.1016/j.jep.2016.06.059] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 05/05/2016] [Accepted: 06/24/2016] [Indexed: 06/06/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE The flower of Edgeworthia gardneri (Wall.) Meisn., locally named "Lvluohua, ", has been widely used as Tibetan folk medicine for the treatment of metabolic diseases for a long time. AIM OF THIS STUDY To evaluate the anti-adipogenesis effect of ethyl acetate extract of the flower of E. gardneri (EEG extract) in 3T3-L1 adipocytes. MATERIALS AND METHODS Obesity-related parameters such as lipid accumulation and TG content were determined by Oil red O staining and enzymatic kit, respectively. Western blotting was used to determine the expressions of peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer-binding protein-α (C/EBPα), phosphorylated adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC). Moreover, main constituents of EEG extract were analyzed by high performance liquid chromatography (HPLC). RESULTS EEG extract decreased the lipid and triglyceride (TG) accumulations during the differentiation process and down-regulated the adipogenesis-related transcriptional factors PPARγ and C/EBPα. EEG extract treatment increased AMPK and ACC phosphorylation. In addition, pretreatment with AMPK inhibitor, weakened the inhibitory effects of EEG extract on the expressions of PPARγand C/EBPα. HPLC analysis indicated that tiliroside was the main constituent in EEG extract. CONCLUSIONS These results suggest that EEG extract may exert anti-adipogenic effects through modulation of the AMPK signaling pathway.
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Affiliation(s)
- Die Gao
- College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030, China
| | - Yong-Lan Zhang
- College of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing 400054, China
| | - Feng-Qing Yang
- College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030, China
| | - Fan Li
- College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030, China
| | - Qi-Hui Zhang
- College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030, China
| | - Zhi-Ning Xia
- College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030, China.
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6
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Affourtit C. Mitochondrial involvement in skeletal muscle insulin resistance: A case of imbalanced bioenergetics. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1678-93. [PMID: 27473535 DOI: 10.1016/j.bbabio.2016.07.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 06/19/2016] [Accepted: 07/23/2016] [Indexed: 12/16/2022]
Abstract
Skeletal muscle insulin resistance in obesity associates with mitochondrial dysfunction, but the causality of this association is controversial. This review evaluates mitochondrial models of nutrient-induced muscle insulin resistance. It transpires that all models predict that insulin resistance arises as a result of imbalanced cellular bioenergetics. The nature and precise origin of the proposed insulin-numbing molecules differ between models but all species only accumulate when metabolic fuel supply outweighs energy demand. This observation suggests that mitochondrial deficiency in muscle insulin resistance is not merely owing to intrinsic functional defects, but could instead be an adaptation to nutrient-induced changes in energy expenditure. Such adaptive effects are likely because muscle ATP supply is fully driven by energy demand. This market-economic control of myocellular bioenergetics offers a mechanism by which insulin-signalling deficiency can cause apparent mitochondrial dysfunction, as insulin resistance lowers skeletal muscle anabolism and thus dampens ATP demand and, consequently, oxidative ATP synthesis.
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Affiliation(s)
- Charles Affourtit
- School of Biomedical and Healthcare Sciences, Plymouth University Peninsula Schools of Medicine and Dentistry, Plymouth University, Drake Circus, PL4 8AA Plymouth, UK.
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7
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Weikel KA, Ruderman NB, Cacicedo JM. Unraveling the actions of AMP-activated protein kinase in metabolic diseases: Systemic to molecular insights. Metabolism 2016; 65:634-645. [PMID: 27085772 PMCID: PMC4834453 DOI: 10.1016/j.metabol.2016.01.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 01/08/2016] [Accepted: 01/09/2016] [Indexed: 12/13/2022]
Abstract
AMP-activated protein kinase (AMPK) plays a critical role both in sensing and regulating cellular energy state. In experimental animals, its activation has been shown to reduce the risk of obesity and diabetes-related co-morbidities such as insulin resistance, the metabolic syndrome and atherosclerotic cardiovascular disease. However, in humans, AMPK activation alone often does not completely resolve these conditions. Thus, an improved understanding of AMPK action and regulation in metabolic and other diseases is needed. Herein, we provide a brief description of the enzymatic regulation of AMPK and review its role in maintaining energy homeostasis. We then discuss tissue-specific actions of AMPK that become distorted during such conditions as obesity, type 2 diabetes and certain cancers. Finally, we explore recent findings regarding the interactions of AMPK with mammalian target of rapamycin complex 1 and the lysosome and discuss how changes in these relationships during overnutrition may lead to AMPK dysfunction. A more thorough understanding of AMPK's molecular interactions during diseases of overnutrition may provide key insights for the development of AMPK-based combinatorial treatments for metabolic disease.
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Affiliation(s)
- Karen A Weikel
- Department of Medicine, Boston University School of Medicine and Boston Medical Center, 650 Albany Street, Boston, MA, 02118, USA.
| | - Neil B Ruderman
- Department of Medicine, Boston University School of Medicine and Boston Medical Center, 650 Albany Street, Boston, MA, 02118, USA
| | - José M Cacicedo
- Department of Medicine, Boston University School of Medicine and Boston Medical Center, 650 Albany Street, Boston, MA, 02118, USA
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8
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Balu D, Ouyang J, Parakhia RA, Pitake S, Ochs RS. Ca 2+ effects on glucose transport and fatty acid oxidation in L6 skeletal muscle cell cultures. Biochem Biophys Rep 2016; 5:365-373. [PMID: 28955844 PMCID: PMC5600334 DOI: 10.1016/j.bbrep.2016.01.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 12/17/2015] [Accepted: 01/11/2016] [Indexed: 12/03/2022] Open
Abstract
We examined the effect of Ca2+ on skeletal muscle glucose transport and fatty acid oxidation using L6 cell cultures. Ca2+ stimulation of glucose transport is controversial. We found that caffeine (a Ca2+ secretagogue) stimulation of glucose transport was only evident in a two-part incubation protocol ("post-incubation"). Caffeine was present in the first incubation, the media removed, and labeled glucose added for the second. Caffeine elicited a rise in Ca2+ in the first incubation that was dissipated by the second. This post-incubation procedure was insensitive to glucose concentrations in the first incubation. With a single, direct incubation system (all components present together) caffeine caused a slight inhibition of glucose transport. This was likely due to caffeine induced inhibition of phosphatidylinositol 3-kinase (PI3K), since nanomolar concentrations of wortmannin, a selective PI3K inhibitor, also inhibited glucose transport, and previous investigators have also found this action. We did find a Ca2+ stimulation (using either caffeine or ionomycin) of fatty acid oxidation. This was observed in the absence (but not the presence) of added glucose. We conclude that Ca2+ stimulates fatty acid oxidation at a mitochondrial site, secondary to malonyl CoA inhibition (represented by the presence of glucose in our experiments). In summary, the experiments resolve a controversy on Ca2+ stimulation of glucose transport by skeletal muscle, introduce an important experimental consideration for the measurement of glucose transport, and uncover a new site of action for Ca2+ stimulation of fatty acid oxidation.
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Affiliation(s)
- Darrick Balu
- Dept. Psychiatry, McLean Hospital, MRC I 114, 115 Mill St., Belmont, MA 02478, USA
| | - Jiangyong Ouyang
- Department of Pharmacology, New York University School of Medicine, 550 1st Ave, New York, NY 10016, USA
| | - Rahulkumar A. Parakhia
- Research Institute for Fragrance Materials Inc., 50 Tice Boulevard, Woodcliff Lake, NJ 07407, USA
| | - Saumitra Pitake
- Department of Pharmaceutical Sciences, School of Pharmacy, St. John's University, 8000 Utopia Parkway, Queens, NY 11439, USA
| | - Raymond S. Ochs
- Department of Pharmaceutical Sciences, School of Pharmacy, St. John's University, 8000 Utopia Parkway, Queens, NY 11439, USA
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9
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Jiang LQ, de Castro Barbosa T, Massart J, Deshmukh AS, Löfgren L, Duque-Guimaraes DE, Ozilgen A, Osler ME, Chibalin AV, Zierath JR. Diacylglycerol kinase-δ regulates AMPK signaling, lipid metabolism, and skeletal muscle energetics. Am J Physiol Endocrinol Metab 2016; 310:E51-60. [PMID: 26530149 PMCID: PMC4675797 DOI: 10.1152/ajpendo.00209.2015] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 10/29/2015] [Indexed: 02/08/2023]
Abstract
Decrease of AMPK-related signal transduction and insufficient lipid oxidation contributes to the pathogenesis of obesity and type 2 diabetes. Previously, we identified that diacylglycerol kinase-δ (DGKδ), an enzyme involved in triglyceride biosynthesis, is reduced in skeletal muscle from type 2 diabetic patients. Here, we tested the hypothesis that DGKδ plays a role in maintaining appropriate AMPK action in skeletal muscle and energetic aspects of contraction. Voluntary running activity was reduced in DGKδ(+/-) mice, but glycogen content and mitochondrial markers were unaltered, suggesting that DGKδ deficiency affects skeletal muscle energetics but not mitochondrial protein abundance. We next determined the role of DGKδ in AMPK-related signal transduction and lipid metabolism in isolated skeletal muscle. AMPK activation and signaling were reduced in DGKδ(+/-) mice, concomitant with impaired lipid oxidation and elevated incorporation of free fatty acids into triglycerides. Strikingly, DGKδ deficiency impaired work performance, as evident by altered force production and relaxation dynamics in response to repeated contractions. In conclusion, DGKδ deficiency impairs AMPK signaling and lipid metabolism, thereby highlighting the deleterious role of excessive lipid metabolites in the development of peripheral insulin resistance and type 2 diabetes pathogenesis. DGKδ deficiency also influences skeletal muscle energetics, which may lead to low physical activity levels in type 2 diabetes.
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Affiliation(s)
- Lake Q Jiang
- Department of Molecular Medicine and Surgery, Section for Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Thais de Castro Barbosa
- Department of Molecular Medicine and Surgery, Section for Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Julie Massart
- Department of Molecular Medicine and Surgery, Section for Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Atul S Deshmukh
- Department of Molecular Medicine and Surgery, Section for Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | | | - Daniella E Duque-Guimaraes
- Department of Molecular Medicine and Surgery, Section for Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Arda Ozilgen
- Department of Molecular Medicine and Surgery, Section for Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Megan E Osler
- Department of Molecular Medicine and Surgery, Section for Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Alexander V Chibalin
- Department of Molecular Medicine and Surgery, Section for Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Juleen R Zierath
- Department of Molecular Medicine and Surgery, Section for Integrative Physiology, Karolinska Institutet, Stockholm, Sweden; Department of Physiology and Pharmacology, Section for Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
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10
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Benjamin B, Wada Y, Grundy SM, Szuszkiewicz-Garcia M, Vega GL. Fatty acid oxidation in normotriglyceridemic men. J Clin Lipidol 2015; 10:283-8. [PMID: 27055958 DOI: 10.1016/j.jacl.2015.11.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 11/16/2015] [Accepted: 11/26/2015] [Indexed: 12/01/2022]
Abstract
BACKGROUND Moderate hypertriglyceridemia is frequently associated with central obesity, insulin resistance, and atherogenic dyslipidemia. We showed previously that moderately obese men with hypertriglyceridemia have reduced fatty acid oxidation postabsorptively and postprandially. In the present study, we examined the oxidation of fatty acids in normotriglyceridemic men. OBJECTIVE The study objective was to determine the relation between plasma triglyceride levels and fatty acid oxidation in normotriglyceridemic men. STUDY DESIGN Twenty-four healthy, nonobese White and African American men participated in a cross-sectional metabolic study for evaluation of fatty acid oxidation. Men were healthy, and none took hypolipidemic or hypoglycemic agents. They ingested 200 mg of fat/hour/kg of body weight over a 10-hour period. Plasma levels of triglyceride, nonesterified fatty acids, 3-β-hydroxybutyrate, insulin, and glucagon were measured postabsorptively and postprandially. Chylomicron-triglyceride halflife was also calculated. RESULTS Nonobese White and African-American men had similar anthropometry, levels of plasma triglyceride, lipoprotein cholesterol, nonesterified fatty acids, 3-β-hydroxybutyrate, insulin, and glucagon postabsorptively and postprandially. For the group as a whole, there was a positive and significant correlation between plasma fatty acids and 3-β-hydroxybutyrate and an inverse association between plasma triglyceride levels and 3-β-hydroxybutyrate at baseline. All subjects had increased levels of metabolites of interest postprandially. However, there were no significant changes in plasma insulin, glucagon, or the ratio of insulin to glucagon. The postprandial levels of 3-β-hydroxybutyrate correlated positively with nonesterified fatty acids and inversely with the half-life of chylomicron triglyceride. CONCLUSION Normotriglyceridemia is strongly associated with oxidation of fatty acids by the liver suggesting the possibility that the fatty acid oxidation pathway is a potential target of intervention to prevent hypertriglyceridemia and concomitant fatty liver.
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Affiliation(s)
- Brian Benjamin
- Center for Human Nutrition of the University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Yasuyo Wada
- Center for Human Nutrition of the University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Scott M Grundy
- Center for Human Nutrition of the University of Texas Southwestern Medical Center, Dallas, TX, USA; Medical Service, The Veterans' Administration North Texas Health Care System, Dallas, TX, USA.
| | | | - Gloria Lena Vega
- Center for Human Nutrition of the University of Texas Southwestern Medical Center, Dallas, TX, USA.
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11
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Lee SS, Yoo JH, So YS. Effect of the low- versus high-intensity exercise training on endoplasmic reticulum stress and GLP-1 in adolescents with type 2 diabetes mellitus. J Phys Ther Sci 2015; 27:3063-8. [PMID: 26644644 PMCID: PMC4668135 DOI: 10.1589/jpts.27.3063] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 07/06/2015] [Indexed: 12/17/2022] Open
Abstract
[Purpose] The primary objective of this study was to investigate the effect of low-intensity exercise training compare with high-intensity exercise training on endoplasmic reticulum stress and glucagon-like peptide-1 in adolescents with type 2 diabetes mellitus. [Subjects and Methods] The low-intensity exercise training group performed aerobic exercise training at an intensity of ≤ 45% of the heart rate reserve. The high-intensity interval exercise training group performed interval exercise training at an intensity of ≥ 80% of the heart rate reserve. The exercise-related energy consumption was determined for both groups on a per-week basis (1,200 kcal/week). [Results] Both groups showed improvement in the glucose-regulated protein 78 and dipeptidyl peptidase-4, but the size of the between-group effect was not statistically significant. The high-intensity interval exercise training group showed a significant reduction in percentage body fat. The C-peptide level increased after the 12-weeks programs and was significantly different, between the groups. Fasting glucose, insulin resistance in the fasting state according to homeostasis model assessment, and leptin decreased after the 12-weeks exercise program and were significantly different between the groups, and glucagon-like peptide-1 increased after the 12-week exercise programs and was significantly different between the groups. [Conclusion] In conclusion high-intensity interval exercise training, as defined in this study, may lead to improvements in body composition, glycemic control, endoplasmic reticulum stress, and the glucagon-like peptide-1 in adolescents with type 2 diabetes mellitus.
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Affiliation(s)
- Sung Soo Lee
- Department of Coaching, Dong-A University, Republic of
Korea
| | - Jae Ho Yoo
- Department of Pediatric, College of Medicine, Dong-A
University Medical Center, Repulic of Korea
| | - Yong Seok So
- Department of Physical Education, Dong-A University, Repulic of Korea
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12
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Impact of AMP-Activated Protein Kinase α1 Deficiency on Tissue Injury following Unilateral Ureteral Obstruction. PLoS One 2015; 10:e0135235. [PMID: 26285014 PMCID: PMC4540418 DOI: 10.1371/journal.pone.0135235] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 07/20/2015] [Indexed: 12/22/2022] Open
Abstract
Background AMP-activated protein kinase (Ampk) is a sensor of the cellular energy status and a powerful regulator of metabolism. Activation of Ampk was previously shown to participate in monocyte-to-fibroblast transition and matrix protein production in renal tissue. Thus, the present study explored whether the catalytic Ampkα1 isoform participates in the regulation of the renal fibrotic response following unilateral ureteral obstruction (UUO). Methods UUO was induced in gene-targeted mice lacking functional Ampkα1 (Ampkα1-/-) and in corresponding wild-type mice (Ampkα1+/+). In the obstructed kidney and, for comparison, in the non-obstructed control kidney, quantitative RT-PCR, Western blotting and immunostaining were employed to determine transcript levels and protein abundance, respectively. Results In Ampkα1+/+ mice, UUO significantly up-regulated the protein abundance of the Ampkα1 isoform, but significantly down-regulated the Ampkα2 isoform in renal tissue. Phosphorylated Ampkα protein levels were significantly increased in obstructed kidney tissue of Ampkα1+/+ mice but not of Ampkα1-/- mice. Renal expression of α-smooth muscle actin was increased following UUO, an effect again less pronounced in Ampkα1-/- mice than in Ampkα1+/+ mice. Histological analysis did not reveal a profound effect of Ampkα1 deficiency on collagen 1 protein deposition. UUO significantly increased phosphorylated and total Tgf-ß-activated kinase 1 (Tak1) protein, as well as transcript levels of Tak1-downstream targets c-Fos, Il6, Pai1 and Snai1 in Ampkα1+/+ mice, effects again significantly ameliorated in Ampkα1-/- mice. Moreover, Ampkα1 deficiency inhibited the UUO-induced mRNA expression of Cd206, a marker of M2 macrophages and of Cxcl16, a pro-fibrotic chemokine associated with myeloid fibroblast formation. The effects of Ampkα1 deficiency during UUO were, however, paralleled by increased tubular injury and apoptosis. Conclusions Renal obstruction induces an isoform shift from Ampkα2 towards Ampkα1, which contributes to the signaling involved in cell survival and fibrosis.
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13
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Li LO, Grevengoed TJ, Paul DS, Ilkayeva O, Koves TR, Pascual F, Newgard CB, Muoio DM, Coleman RA. Compartmentalized acyl-CoA metabolism in skeletal muscle regulates systemic glucose homeostasis. Diabetes 2015; 64:23-35. [PMID: 25071025 PMCID: PMC4274800 DOI: 10.2337/db13-1070] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The impaired capacity of skeletal muscle to switch between the oxidation of fatty acid (FA) and glucose is linked to disordered metabolic homeostasis. To understand how muscle FA oxidation affects systemic glucose, we studied mice with a skeletal muscle-specific deficiency of long-chain acyl-CoA synthetase (ACSL)1. ACSL1 deficiency caused a 91% loss of ACSL-specific activity and a 60-85% decrease in muscle FA oxidation. Acsl1(M-/-) mice were more insulin sensitive, and, during an overnight fast, their respiratory exchange ratio was higher, indicating greater glucose use. During endurance exercise, Acsl1(M-/-) mice ran only 48% as far as controls. At the time that Acsl1(M-/-) mice were exhausted but control mice continued to run, liver and muscle glycogen and triacylglycerol stores were similar in both genotypes; however, plasma glucose concentrations in Acsl1(M-/-) mice were ∼40 mg/dL, whereas glucose concentrations in controls were ∼90 mg/dL. Excess use of glucose and the likely use of amino acids for fuel within muscle depleted glucose reserves and diminished substrate availability for hepatic gluconeogenesis. Surprisingly, the content of muscle acyl-CoA at exhaustion was markedly elevated, indicating that acyl-CoAs synthesized by other ACSL isoforms were not available for β-oxidation. This compartmentalization of acyl-CoAs resulted in both an excessive glucose requirement and severely compromised systemic glucose homeostasis.
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Affiliation(s)
- Lei O Li
- Department of Nutrition, University of North Carolina, Chapel Hill, NC
| | | | - David S Paul
- Department of Nutrition, University of North Carolina, Chapel Hill, NC
| | - Olga Ilkayeva
- Sarah W. Stedman Nutrition and Metabolism Center, and Departments of Medicine and Pharmacology and Cancer Biology, Duke University, Durham, NC
| | - Timothy R Koves
- Sarah W. Stedman Nutrition and Metabolism Center, and Departments of Medicine and Pharmacology and Cancer Biology, Duke University, Durham, NC
| | - Florencia Pascual
- Department of Nutrition, University of North Carolina, Chapel Hill, NC
| | - Christopher B Newgard
- Sarah W. Stedman Nutrition and Metabolism Center, and Departments of Medicine and Pharmacology and Cancer Biology, Duke University, Durham, NC
| | - Deborah M Muoio
- Sarah W. Stedman Nutrition and Metabolism Center, and Departments of Medicine and Pharmacology and Cancer Biology, Duke University, Durham, NC
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14
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Davies NA, Watkeys L, Butcher L, Potter S, Hughes MG, Moir H, Morris K, Thomas AW, Webb R. The contributions of oxidative stress, oxidised lipoproteins and AMPK towards exercise-associated PPARγ signalling within human monocytic cells. Free Radic Res 2014; 49:45-56. [DOI: 10.3109/10715762.2014.978311] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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15
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Syed DN, Lall RK, Chamcheu JC, Haidar O, Mukhtar H. Involvement of ER stress and activation of apoptotic pathways in fisetin induced cytotoxicity in human melanoma. Arch Biochem Biophys 2014; 563:108-117. [PMID: 25016296 DOI: 10.1016/j.abb.2014.06.034] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 06/04/2014] [Accepted: 06/15/2014] [Indexed: 02/07/2023]
Abstract
The prognosis of malignant melanoma remains poor in spite of recent advances in therapeutic strategies for the deadly disease. Fisetin, a dietary flavonoid is currently being investigated for its growth inhibitory properties in various cancer models. We previously showed that fisetin inhibited melanoma growth in vitro and in vivo. Here, we evaluated the molecular basis of fisetin induced cytotoxicity in metastatic human melanoma cells. Fisetin treatment induced endoplasmic reticulum (ER) stress in highly aggressive A375 and 451Lu human melanoma cells, as revealed by up-regulation of ER stress markers including IRE1α, XBP1s, ATF4 and GRP78. Time course analysis indicated that the ER stress was associated with activation of the extrinsic and intrinsic apoptotic pathways. Fisetin treated 2-D melanoma cultures displayed autophagic response concomitant with induction of apoptosis. Prolonged treatment (16days) with fisetin in a 3-D reconstituted melanoma model resulted in inhibition of melanoma progression with significant apoptosis, as evidenced by increased staining of cleaved Caspase-3 in the treated constructs. However, no difference in the expression of autophagic marker LC-3 was noted between treated and control groups. Fisetin treatment to 2-D melanoma cultures resulted in phosphorylation and activation of the multifunctional AMP-activated protein kinase (AMPK) involved in the regulation of diverse cellular processes, including autophagy and apoptosis. Silencing of AMPK failed to prevent cell death indicating that fisetin induced cytotoxicity is mediated through both AMPK-dependent and -independent mechanisms. Taken together, our studies confirm apoptosis as the primary mechanism through which fisetin inhibits melanoma cell growth and that activation of both extrinsic and intrinsic pathways contributes to fisetin induced cytotoxicity.
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Affiliation(s)
- Deeba N Syed
- Department of Dermatology, University of Wisconsin, Madison
| | - Rahul K Lall
- Department of Dermatology, University of Wisconsin, Madison
| | | | - Omar Haidar
- Department of Dermatology, University of Wisconsin, Madison
| | - Hasan Mukhtar
- Department of Dermatology, University of Wisconsin, Madison
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16
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Shin JS, Huh YS. Effect of intake of gardenia fruits and combined exercise of middle-aged obese women on hormones regulating energy metabolism. J Exerc Nutrition Biochem 2014; 18:41-9. [PMID: 25566438 PMCID: PMC4241929 DOI: 10.5717/jenb.2014.18.1.41] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 02/05/2014] [Accepted: 02/13/2014] [Indexed: 12/05/2022] Open
Abstract
[Purpose] This study is aimed at analyzing how exercise and gardenia affect hormones that regulate energy metabolism by having middle aged, obese women exercise and take gardenia simultaneously. [Methods] This study assigned a total of 35 middle-aged obese women with body fat percentage of more than 35 percent into 9 people of the complex treatment group of intake of gardenia and exercise, 9 people of the exercise group, 9 people of the gardenia group and 8 people of the control group in order to find out the effect of the intake of gardenia fruits and Combined exercise of 8 weeks on the body composition, hormones regulating energy metabolism. This study arranged .08 g per weight of 1 kg of the gardenia fruits to be taken twice a day for 8 weeks after breakfast and dinner through the numerical method of roasting the gardenia fruits on fire. And the exercise program was set to be five times a week for 8 weeks, whereas the aerobic exercise of 60 to 70 minutes was 50 to 60 percent for HRmax; thus, the resistance exercise was set to be 1-RM 50 percent. As for the data analysis, the two-way repeated measures ANOVA was utilized for the analysis of interactive effect between groups and times. [Results] Thus, the obtained conclusion is as follows: The %fat and WHR has decreased further in the gardenia+exercise group and the exercise group as compared with the control group. And the visceral fat area has decreased further in the gardenia and exercise group and the gardenia group as compared with the control group (p<.05). In addition, the gardenia+exercise group and the exercise group were found to have a significant improvement effect in all the items of body composition, and the gardenia group has reduced the fat percentage and BMI after the treatment (p<.05). Leptin has decreased further in the gardenia+exercise group and the exercise group as compared with the control group, and the insulin resistance and GLP-1 have decreased in all the treatment groups (p<.05). [Conclusion] As a result of this study, all the treatment groups were found to have an improvement effect of research variables in general; therefore, the single treatment and complex treatment for the middle-aged obese women were found to have a positive impact on body composition, adjusting factors for energy metabolism. Also, the complex treatment was found to be more positive in terms of change amount. In particular, in the case of visceral fat area that is the major risk factor for metabolic disease of middle-aged obese women, it was found to have decreased further in the complex treatment group than the gardenia group; therefore, the complex treatment was found to be more advantageous.
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Affiliation(s)
- Jae Sug Shin
- Department of Physical Education, Kyungnam University, Changwon, Korea
| | - Yu Sub Huh
- Department of Physical Education, Kyungnam University, Changwon, Korea
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17
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Kimber NE, Cameron-Smith D, McGee SL, Hargreaves M. Skeletal muscle fat metabolism after exercise in humans: influence of fat availability. J Appl Physiol (1985) 2013; 114:1577-85. [PMID: 23519231 DOI: 10.1152/japplphysiol.00824.2012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The mechanisms facilitating increased skeletal muscle fat oxidation following prolonged, strenuous exercise remain poorly defined. The aim of this study was to examine the influence of plasma free fatty acid (FFA) availability on intramuscular malonyl-CoA concentration and the regulation of whole-body fat metabolism during a 6-h postexercise recovery period. Eight endurance-trained men performed three trials, consisting of 1.5 h high-intensity and exhaustive exercise, followed by infusion of saline, saline + nicotinic acid (NA; low FFA), or Intralipid and heparin [high FFA (HFA)]. Muscle biopsies were obtained at the end of exercise (0 h) and at 3 and 6 h in recovery. Ingestion of NA suppressed the postexercise plasma FFA concentration throughout recovery (P < 0.01), except at 4 h. The alteration of the availability of plasma FFA during recovery induced a significant increase in whole-body fat oxidation during the 6-h period for HFA (52.2 ± 4.8 g) relative to NA (38.4 ± 3.1 g; P < 0.05); however, this response was unrelated to changes in skeletal muscle malonyl-CoA and acetyl-CoA carboxylase (ACC)β phosphorylation, suggesting mechanisms other than phosphorylation-mediated changes in ACC activity may have a role in regulating fat metabolism in human skeletal muscle during postexercise recovery. Despite marked changes in plasma FFA availability, no significant changes in intramuscular triglyceride concentrations were detected. These data suggest that the regulation of postexercise skeletal muscle fat oxidation in humans involves factors other than the 5'AMP-activated protein kinase-ACCβ-malonyl-CoA signaling pathway, although malonyl-CoA-mediated regulation cannot be excluded completely in the acute recovery period.
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Affiliation(s)
- Nicholas E Kimber
- Department of Applied Science and Allied Health, Christchurch Polytechnic Institute of Technology, Christchurch, New Zealand.
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18
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Plasma protein changes in horse after prolonged physical exercise: A proteomic study. J Proteomics 2012; 75:4494-504. [DOI: 10.1016/j.jprot.2012.04.014] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 03/26/2012] [Accepted: 04/10/2012] [Indexed: 11/19/2022]
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19
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Fonseca BD, Diering GH, Bidinosti MA, Dalal K, Alain T, Balgi AD, Forestieri R, Nodwell M, Rajadurai CV, Gunaratnam C, Tee AR, Duong F, Andersen RJ, Orlowski J, Numata M, Sonenberg N, Roberge M. Structure-activity analysis of niclosamide reveals potential role for cytoplasmic pH in control of mammalian target of rapamycin complex 1 (mTORC1) signaling. J Biol Chem 2012; 287:17530-17545. [PMID: 22474287 DOI: 10.1074/jbc.m112.359638] [Citation(s) in RCA: 122] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Mammalian target of rapamycin complex 1 (mTORC1) signaling is frequently dysregulated in cancer. Inhibition of mTORC1 is thus regarded as a promising strategy in the treatment of tumors with elevated mTORC1 activity. We have recently identified niclosamide (a Food and Drug Administration-approved antihelminthic drug) as an inhibitor of mTORC1 signaling. In the present study, we explored possible mechanisms by which niclosamide may inhibit mTORC1 signaling. We tested whether niclosamide interferes with signaling cascades upstream of mTORC1, the catalytic activity of mTOR, or mTORC1 assembly. We found that niclosamide does not impair PI3K/Akt signaling, nor does it inhibit mTORC1 kinase activity. We also found that niclosamide does not interfere with mTORC1 assembly. Previous studies in helminths suggest that niclosamide disrupts pH homeostasis of the parasite. This prompted us to investigate whether niclosamide affects the pH balance of cancer cells. Experiments in both breast cancer cells and cell-free systems demonstrated that niclosamide possesses protonophoric activity in cells and in vitro. In cells, niclosamide dissipated protons (down their concentration gradient) from lysosomes to the cytosol, effectively lowering cytoplasmic pH. Notably, analysis of five niclosamide analogs revealed that the structural features of niclosamide required for protonophoric activity are also essential for mTORC1 inhibition. Furthermore, lowering cytoplasmic pH by means other than niclosamide treatment (e.g. incubation with propionic acid or bicarbonate withdrawal) recapitulated the inhibitory effects of niclosamide on mTORC1 signaling, lending support to a possible role for cytoplasmic pH in the control of mTORC1. Our data illustrate a potential mechanism for chemical inhibition of mTORC1 signaling involving modulation of cytoplasmic pH.
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Affiliation(s)
- Bruno D Fonseca
- Department of Biochemistry and Molecular Biology, 2350 Health Sciences Mall, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada; Department of Biochemistry, 1160 Pine Avenue West, Rosalind and Morris Goodman Cancer Centre, McGill University, Montreal, Quebec H3A 1A3, Canada.
| | - Graham H Diering
- Department of Biochemistry and Molecular Biology, 2350 Health Sciences Mall, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Michael A Bidinosti
- Department of Biochemistry, 1160 Pine Avenue West, Rosalind and Morris Goodman Cancer Centre, McGill University, Montreal, Quebec H3A 1A3, Canada
| | - Kush Dalal
- Department of Biochemistry and Molecular Biology, 2350 Health Sciences Mall, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Tommy Alain
- Department of Biochemistry, 1160 Pine Avenue West, Rosalind and Morris Goodman Cancer Centre, McGill University, Montreal, Quebec H3A 1A3, Canada
| | - Aruna D Balgi
- Department of Biochemistry and Molecular Biology, 2350 Health Sciences Mall, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Roberto Forestieri
- Departments of Chemistry and Earth and Ocean Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Matt Nodwell
- Departments of Chemistry and Earth and Ocean Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Charles V Rajadurai
- Department of Biochemistry, 1160 Pine Avenue West, Rosalind and Morris Goodman Cancer Centre, McGill University, Montreal, Quebec H3A 1A3, Canada
| | - Cynthia Gunaratnam
- Department of Biochemistry and Molecular Biology, 2350 Health Sciences Mall, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Andrew R Tee
- Institute of Medical Genetics, Wales College of Medicine, Cardiff University, Heath Park Way, Cardiff CF14 4XN, United Kingdom
| | - Franck Duong
- Department of Biochemistry and Molecular Biology, 2350 Health Sciences Mall, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Raymond J Andersen
- Departments of Chemistry and Earth and Ocean Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - John Orlowski
- Department of Physiology, 3655 Promenade Sir William Osler, Bellini Building, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Masayuki Numata
- Department of Biochemistry and Molecular Biology, 2350 Health Sciences Mall, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Nahum Sonenberg
- Department of Biochemistry, 1160 Pine Avenue West, Rosalind and Morris Goodman Cancer Centre, McGill University, Montreal, Quebec H3A 1A3, Canada
| | - Michel Roberge
- Department of Biochemistry and Molecular Biology, 2350 Health Sciences Mall, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.
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20
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Thomas AW, Davies NA, Moir H, Watkeys L, Ruffino JS, Isa SA, Butcher LR, Hughes MG, Morris K, Webb R. Exercise-associated generation of PPARγ ligands activates PPARγ signaling events and upregulates genes related to lipid metabolism. J Appl Physiol (1985) 2012; 112:806-15. [DOI: 10.1152/japplphysiol.00864.2011] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The aim of the present study was to test the hypotheses that exercise is associated with generation of peroxisome proliferator-activated receptor-γ (PPARγ) ligands in the plasma and that this may activate PPARγ signaling within circulating monocytes, thus providing a mechanism to underpin the exercise-induced antiatherogenic benefits observed in previous studies. A cohort of healthy individuals undertook an 8-wk exercise-training program; samples were obtained before (Pre) and after (Post) standardized submaximal exercise bouts (45 min of cycling at 70% of maximal O2 uptake, determined at baseline) at weeks 0, 4, and 8. Addition of plasma samples to PPARγ response element (PPRE)-luciferase reporter gene assays showed increased PPARγ activity following standardized exercise bouts (Post/Pre = 1.23 ± 0.10 at week 0, P < 0.05), suggesting that PPARγ ligands were generated during exercise. However, increases in PPARγ/PPRE-luciferase activity in response to the same standardized exercise bout were blunted during the training program (Post/Pre = 1.18 ± 0.14 and 1.10 ± 0.10 at weeks 4 and 8, respectively, P > 0.05 for both), suggesting that the relative intensity of the exercise may affect PPARγ ligand generation. In untrained individuals, specific transient increases in monocyte expression of PPARγ-regulated genes were observed within 1.5–3 h of exercise (1.7 ± 0.4, 2.6 ± 0.4, and 1.4 ± 0.1 fold for CD36, liver X receptor-α, and ATP-binding cassette subfamily A member 1, respectively, P < 0.05), with expression returning to basal levels within 24 h. In contrast, by the end of the exercise program, expression at the protein level of PPARγ target genes had undergone sustained increases that were not associated with an individual exercise bout (e.g., week 8 Pre/ week 0 Pre = 2.79 ± 0.61 for CD36, P < 0.05). Exercise is known to upregulate PPARγ-controlled genes to induce beneficial effects in skeletal muscle (e.g., mitochondrial biogenesis and aerobic respiration). We suggest that parallel exercise-induced benefits may occur in monocytes, as monocyte PPARγ activation has been linked to beneficial antidiabetic effects (e.g., exercise-induced upregulation of monocytic PPARγ-controlled genes is associated with reverse cholesterol transport and anti-inflammatory effects). Thus, exercise-triggered monocyte PPARγ activation may constitute an additional rationale for prescribing exercise to type 2 diabetes patients.
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Affiliation(s)
| | | | - H. Moir
- Cardiff School of Health Sciences and
| | | | | | - S. A. Isa
- Cardiff School of Health Sciences and
| | | | - M. G. Hughes
- Cardiff School of Sport, University of Wales Institute Cardiff, Cardiff, United Kingdom
| | - K. Morris
- Cardiff School of Health Sciences and
| | - R. Webb
- Cardiff School of Health Sciences and
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Holness MJ, Sugden PH, Silvestre MF, Sugden MC. Actions and interactions of AMPK with insulin, the peroxisomal-proliferator activated receptors and sirtuins. Expert Rev Endocrinol Metab 2012; 7:191-208. [PMID: 30764011 DOI: 10.1586/eem.12.9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
AMP-activated protein kinase (AMPK) activity responds to a requirement to increase cellular ATP production and/or to conserve available ATP. AMPK is therefore central to the mechanisms of adjustment to fluctuating energy demand or metabolic substrate supply. AMPK has important actions in several insulin-responsive tissues, as well as in the pancreatic β cell, through which it can modulate glycemic control, insulin action and metabolic substrate selection and disposal. We review recent novel findings elucidating the mechanisms by which AMPK activation can correct impaired insulin action. However, we also emphasize not only the similarities, but also the differences in the actions of insulin and AMPK. We focus on metabolic interfaces between AMPK, peroxisomal proliferator-activated receptors, sirtuins and mTORC.
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Affiliation(s)
- Mark J Holness
- a Centre for Diabetes, Blizard Institute, Barts and the London School of Medicine and Dentistry, 4 Newark Street, Whitechapel, London, E1 2AT, UK.
| | - Peter H Sugden
- b Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, RG6 6BX, UK
| | - Marta Fp Silvestre
- a Centre for Diabetes, Blizard Institute, Barts and the London School of Medicine and Dentistry, 4 Newark Street, Whitechapel, London, E1 2AT, UK.
| | - Mary C Sugden
- a Centre for Diabetes, Blizard Institute, Barts and the London School of Medicine and Dentistry, 4 Newark Street, Whitechapel, London, E1 2AT, UK.
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Stucchi P, Gil-Ortega M, Merino B, Guzmán-Ruiz R, Cano V, Valladolid-Acebes I, Somoza B, Le Gonidec S, Argente J, Valet P, Chowen JA, Fernández-Alfonso M, Ruiz-Gayo M. Circadian feeding drive of metabolic activity in adipose tissue and not hyperphagia triggers overweight in mice: is there a role of the pentose-phosphate pathway? Endocrinology 2012; 153:690-9. [PMID: 22147018 DOI: 10.1210/en.2011-1023] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
High-fat (HF) diets trigger an increase in adipose tissue and body weight (BW) and disordered eating behavior. Our study deals with the hypothesis that circadian distribution of energy intake is more relevant for BW dynamics than diet composition. Four-week-old mice were exposed for 8 wk to a HF diet and compared with animals receiving control chow. HF mice progressively increased BW, decreased the amount of nocturnal (1800-0900 h) calories (energy or food intake) (30%) and increased diurnal (0900-1800 h) caloric intake (energy or food intake), although total daily intake was identical between groups. Animals were killed at 3-h intervals and plasma insulin, leptin, corticosterone, glucose, and fatty acid levels quantified. Adipose tissue was weighed, and enzymatic activities integral to the pentose phosphate pathway (PPP) assayed in lumbar adipose tissue. Phosphorylated AMP-dependent protein kinase and fatty acid synthase were quantified by Western blotting. In HF mice, there was a shift in the circadian oscillations of plasma parameters together with an inhibition of PPP activity and a decrease in phosphorylated AMP-dependent protein kinase and fatty acid synthase. In a second experiment, HF mice were forced to adhere to a circadian pattern of food intake similar to that in control animals. In this case, BW, adipose tissue, morning plasma parameters and PPP activity appeared to be normal. These data indicate that disordered feeding behavior can trigger BW gain independently of food composition and daily energy intake. Because PPP is the main source of reduced nicotinamide adenine dinucleotide phosphate, we suggest that PPP inhibition might be an early marker of adipose dysfunction in diet-induced obesity.
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Affiliation(s)
- Paula Stucchi
- Instituto Pluridisciplinar and Departamento de Farmacología, Facultad de Farmacia, Universidad Complutense de Madrid, 28040 Madrid, Spain
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New perspectives on nutritional interventions to augment lipid utilisation during exercise. Br J Nutr 2011; 107:339-49. [PMID: 22136984 DOI: 10.1017/s0007114511006684] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The enhancement of fat oxidation during exercise is an aim for both recreational exercising individuals and endurance athletes. Nutritional status may explain a large part of the variation in maximal rates of fat oxidation during exercise. This review reveals novel insights into nutritional manipulation of substrate selection during exercise, explaining putative mechanisms of action and evaluating the current evidence. Lowering the glycaemic index of the pre-exercise meal can enhance lipid utilisation by up to 100 % through reduced insulin concentrations, although its application may be restricted to specific training sessions rather than competition. Chronic effects of dietary glycaemic index are less clear and warrant future study before firm recommendations can be made. A flurry of recent advances has overthrown the conventional view of l-carnitine supplementation, with skeletal muscle uptake possible under certain dietary conditions and providing a strategy to influence energy metabolism in an exercise intensity-dependent manner. Use of non-carbohydrate nutrients to stimulate muscle l-carnitine uptake may prove more beneficial for optimising lipid utilisation, but this requires more research. Studies investigating fish oil supplementation on fat oxidation during exercise are conflicting. In spite of some strong putative mechanisms, the only crossover trial showed no significant effect on lipid use during exercise. Ca may increase NEFA availability although it is not clear whether these effects occur. Ca and caffeine can increase NEFA availability under certain circumstances which could theoretically enhance fat oxidation, yet strong experimental evidence for this effect during exercise is lacking. Co-administration of nutrients to maximise their effectiveness needs further investigation.
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Ceccarelli SM, Chomienne O, Gubler M, Arduini A. Carnitine Palmitoyltransferase (CPT) Modulators: A Medicinal Chemistry Perspective on 35 Years of Research. J Med Chem 2011; 54:3109-52. [DOI: 10.1021/jm100809g] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Simona M. Ceccarelli
- Pharmaceuticals Division, F. Hoffmann-La Roche Ltd., CH- 4070 Basel, Switzerland
| | - Odile Chomienne
- Pharmaceuticals Division, F. Hoffmann-La Roche Ltd., CH- 4070 Basel, Switzerland
| | - Marcel Gubler
- Pharmaceuticals Division, F. Hoffmann-La Roche Ltd., CH- 4070 Basel, Switzerland
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Labbé A, Garand C, Cogger VC, Paquet ER, Desbiens M, Le Couteur DG, Lebel M. Resveratrol improves insulin resistance hyperglycemia and hepatosteatosis but not hypertriglyceridemia, inflammation, and life span in a mouse model for Werner syndrome. J Gerontol A Biol Sci Med Sci 2010; 66:264-78. [PMID: 20974729 DOI: 10.1093/gerona/glq184] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Werner syndrome is a premature aging disorder caused by mutations in a RecQ-like DNA helicase. Mice lacking the helicase domain of the WRN homologue exhibit many features of Werner syndrome, including a pro-oxidant status and a shorter mean life span. Here, we show that resveratrol supplementation improved the hyperglycemia and the insulin resistance phenotype in these Wrn mutant mice. In addition, resveratrol reversed liver steatosis, lipid peroxidaton, and the defenestration phenotypes observed in such mice. Resveratrol, however, did not improve the hypertriglyceridemia, inflammatory stress, nor extend the mean life span of these mutant mice. Microarray and biologic pathway enrichment analyses on liver tissues revealed that resveratrol mainly decreased lipidogenesis and increased genes involved in the insulin signaling pathway and the glutathione metabolism in Wrn mutant mice. Finally, resveratrol-treated mutant mice exhibited an increase in the frequency of lymphoma and of several solid tumors. These results indicate that resveratrol supplementation might exert at least metabolic benefits for Werner syndrome patients.
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Affiliation(s)
- Adam Labbé
- Department of Molecular Biology, Medical Biochemistry, and Pathology, Centre de Recherche en Cancérologie de l'Université Laval, Hôpital Hôtel-Dieu de Québec, Québec, Canada
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5-aminoimidazole-4-carboxamide ribonucleoside and AMP-activated protein kinase inhibit signalling through NF-κB. Immunol Cell Biol 2010; 88:754-60. [PMID: 20404837 DOI: 10.1038/icb.2010.44] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Activation of nuclear factor-kappa B (NF-κB) is one of the most important pro-inflammatory mechanisms in disease. In this study, we show that 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR), an intermediate in nucleoside metabolism, inhibits signalling by NF-κB in three cell types, including bovine aortic endothelial cells (BAEC). The block in the NF-κB signalling pathway occurred beyond degradation of IκB-α and movement of p65 into the nucleus of BAEC. There was, however, reduced binding of NF-κB from AICAR-treated cells to a κB-consensus oligonucleotide, suggesting that part of the mechanism was a reduction in NF-κB DNA-binding activity. Although AICAR is metabolized to ZMP and then adenosine, adenosine had no effect on activation of an NF-κB reporter. ZMP, however, activates the metabolic stress-sensing AMP-activated protein kinase (AMPK). Transfection of active AMPK into BAEC reduced NF-κB reporter activity compared with a kinase-dead mutant, suggesting that part of the ability of AICAR to inhibit NF-κB signalling is due to activation of AMPK. Inhibition of NF-κB signalling may be important in the anti-inflammatory action of drugs such as sulfasalazine and methotrexate, which led to the accumulation of AICAR within target cells.
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