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Russell-Guzmán J, Américo-Da Silva L, Cadagan C, Maturana M, Palomero J, Estrada M, Barrientos G, Buvinic S, Hidalgo C, Llanos P. Activation of the ROS/TXNIP/NLRP3 pathway disrupts insulin-dependent glucose uptake in skeletal muscle of insulin-resistant obese mice. Free Radic Biol Med 2024; 222:187-198. [PMID: 38897422 DOI: 10.1016/j.freeradbiomed.2024.06.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 05/31/2024] [Accepted: 06/15/2024] [Indexed: 06/21/2024]
Abstract
Oxidative stress and the activation of the nucleotide-binding domain, leucine-rich-containing family, pyrin domain containing 3 (NLRP3) inflammasome have been linked to insulin resistance in skeletal muscle. In immune cells, the exacerbated generation of reactive oxygen species (ROS) activates the NLRP3 inflammasome, by facilitating the interaction between thioredoxin interacting protein (TXNIP) and NLRP3. However, the precise role of ROS/TXNIP-dependent NLRP3 inflammasome activation in skeletal muscle during obesity-induced insulin resistance remains undefined. Here, we induced insulin resistance in C57BL/6J mice by feeding them for 8 weeks with a high-fat diet (HFD) and explored whether the ROS/TXNIP/NLRP3 pathway was involved in the induction of insulin resistance in skeletal muscle. Skeletal muscle fibers from insulin-resistant mice exhibited increased oxidative stress, as evidenced by elevated malondialdehyde levels, and altered peroxiredoxin 2 dimerization. Additionally, these fibers displayed augmented activation of the NLRP3 inflammasome, accompanied by heightened ROS-dependent proximity between TXNIP and NLRP3, which was abolished by the antioxidant N-acetylcysteine (NAC). Inhibition of the NLRP3 inflammasome with MCC950 or suppressing the ROS/TXNIP/NLRP3 pathway with NAC restored insulin-dependent glucose uptake in muscle fibers from insulin-resistant mice. These findings provide insights into the mechanistic link between oxidative stress, NLRP3 inflammasome activation, and obesity-induced insulin resistance in skeletal muscle.
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Affiliation(s)
- Javier Russell-Guzmán
- Institute for Research in Dental Sciences, Faculty of Dentistry, Universidad de Chile, Santiago, 8380544, Chile; Pedagogy in Physical Education, Faculty of Education, Universidad Autónoma de Chile, Santiago, 8910123, Chile
| | - Luan Américo-Da Silva
- Institute for Research in Dental Sciences, Faculty of Dentistry, Universidad de Chile, Santiago, 8380544, Chile
| | - Cynthia Cadagan
- Institute for Research in Dental Sciences, Faculty of Dentistry, Universidad de Chile, Santiago, 8380544, Chile
| | - Martín Maturana
- Institute for Research in Dental Sciences, Faculty of Dentistry, Universidad de Chile, Santiago, 8380544, Chile
| | - Jesús Palomero
- Department of Physiology and Pharmacology, Faculty of Medicine, Campus Miguel de Unamuno, Universidad de Salamanca, Salamanca, 37007, Spain
| | - Manuel Estrada
- Institute of Biomedical Sciences, Facultad de Medicina, Universidad de Chile, Santiago, 8380000, Chile
| | - Genaro Barrientos
- Institute of Biomedical Sciences, Facultad de Medicina, Universidad de Chile, Santiago, 8380000, Chile; Center for Exercise, Metabolism and Cancer, Facultad de Medicina, Universidad de Chile, Santiago, 8380453, Chile
| | - Sonja Buvinic
- Institute for Research in Dental Sciences, Faculty of Dentistry, Universidad de Chile, Santiago, 8380544, Chile; Center for Exercise, Metabolism and Cancer, Facultad de Medicina, Universidad de Chile, Santiago, 8380453, Chile
| | - Cecilia Hidalgo
- Institute of Biomedical Sciences, Facultad de Medicina, Universidad de Chile, Santiago, 8380000, Chile; Center for Exercise, Metabolism and Cancer, Facultad de Medicina, Universidad de Chile, Santiago, 8380453, Chile; Department of Neurosciences and Biomedical Neuroscience Institute, Universidad de Chile, Santiago, 8380453, Chile
| | - Paola Llanos
- Institute for Research in Dental Sciences, Faculty of Dentistry, Universidad de Chile, Santiago, 8380544, Chile; Center for Exercise, Metabolism and Cancer, Facultad de Medicina, Universidad de Chile, Santiago, 8380453, Chile.
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Henriquez-Olguin C, Meneses-Valdes R, Raun SH, Gallero S, Knudsen JR, Li Z, Li J, Sylow L, Jaimovich E, Jensen TE. NOX2 deficiency exacerbates diet-induced obesity and impairs molecular training adaptations in skeletal muscle. Redox Biol 2023; 65:102842. [PMID: 37572454 PMCID: PMC10440567 DOI: 10.1016/j.redox.2023.102842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 08/05/2023] [Indexed: 08/14/2023] Open
Abstract
The production of reactive oxygen species (ROS) by NADPH oxidase (NOX) 2 has been linked to both insulin resistance and exercise training adaptations in skeletal muscle. This study explores the previously unexamined role of NOX2 in the interplay between diet-induced insulin resistance and exercise training (ET). Using a mouse model that harbors a point mutation in the essential NOX2 regulatory subunit, p47phox (Ncf1*), we investigated the impact of this mutation on various metabolic adaptations. Wild-type (WT) and Ncf1* mice were assigned to three groups: chow diet, 60% energy fat diet (HFD), and HFD with access to running wheels (HFD + E). After a 16-week intervention, a comprehensive phenotypic assessment was performed, including body composition, glucose tolerance, energy intake, muscle insulin signaling, redox-related proteins, and mitochondrial adaptations. The results revealed that NOX2 deficiency exacerbated the impact of HFD on body weight, body composition, and glucose intolerance. Moreover, in Ncf1* mice, ET did not improve glucose tolerance or increase muscle cross-sectional area. ET normalized body fat independently of genotype. The lack of NOX2 activity during ET reduced several metabolic adaptations in skeletal muscle, including insulin signaling and expression of Hexokinase II and oxidative phosphorylation complexes. In conclusion, these findings suggest that NOX2 mediates key beneficial effects of exercise training in the context of diet-induced obesity.
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Affiliation(s)
- Carlos Henriquez-Olguin
- The August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise, and Sports, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100, Copenhagen, Denmark; Exercise Science Laboratory, Faculty of Medicine, Universidad Finis Terrae, Av. Pedro de Valdivia 1509, Santiago, Chile.
| | - Roberto Meneses-Valdes
- The August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise, and Sports, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100, Copenhagen, Denmark; Center for Exercise, Metabolism and Cancer, ICBM, Universidad de Chile, 8380453, Santiago, Chile
| | - Steffen H Raun
- The August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise, and Sports, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100, Copenhagen, Denmark; Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 3 Blegdamsvej, Copenhagen N, Denmark
| | - Samantha Gallero
- The August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise, and Sports, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100, Copenhagen, Denmark
| | - Jonas R Knudsen
- The August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise, and Sports, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100, Copenhagen, Denmark
| | - Zhencheng Li
- College of Physical Education, Chongqing University, Chongqing, 400044, CN, China
| | - Jingwen Li
- School of Medicine and Nursing, Huzhou University, Huzhou, 313000, CN, China
| | - Lykke Sylow
- The August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise, and Sports, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100, Copenhagen, Denmark; Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 3 Blegdamsvej, Copenhagen N, Denmark
| | - Enrique Jaimovich
- Center for Exercise, Metabolism and Cancer, ICBM, Universidad de Chile, 8380453, Santiago, Chile
| | - Thomas E Jensen
- The August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise, and Sports, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100, Copenhagen, Denmark.
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Bayonés L, Guerra-Fernández MJ, Hinostroza F, Báez-Matus X, Vásquez-Navarrete J, Gallo LI, Parra S, Martínez AD, González-Jamett A, Marengo FD, Cárdenas AM. Gain-of-Function Dynamin-2 Mutations Linked to Centronuclear Myopathy Impair Ca2+-Induced Exocytosis in Human Myoblasts. Int J Mol Sci 2022; 23:ijms231810363. [PMID: 36142275 PMCID: PMC9499313 DOI: 10.3390/ijms231810363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 08/26/2022] [Accepted: 09/02/2022] [Indexed: 11/16/2022] Open
Abstract
Gain-of-function mutations of dynamin-2, a mechano-GTPase that remodels membrane and actin filaments, cause centronuclear myopathy (CNM), a congenital disease that mainly affects skeletal muscle tissue. Among these mutations, the variants p.A618T and p.S619L lead to a gain of function and cause a severe neonatal phenotype. By using total internal reflection fluorescence microscopy (TIRFM) in immortalized human myoblasts expressing the pH-sensitive fluorescent protein (pHluorin) fused to the insulin-responsive aminopeptidase IRAP as a reporter of the GLUT4 vesicle trafficking, we measured single pHluorin signals to investigate how p.A618T and p.S619L mutations influence exocytosis. We show here that both dynamin-2 mutations significantly reduced the number and durations of pHluorin signals induced by 10 μM ionomycin, indicating that in addition to impairing exocytosis, they also affect the fusion pore dynamics. These mutations also disrupt the formation of actin filaments, a process that reportedly favors exocytosis. This altered exocytosis might importantly disturb the plasmalemma expression of functional proteins such as the glucose transporter GLUT4 in skeletal muscle cells, impacting the physiology of the skeletal muscle tissue and contributing to the CNM disease.
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Affiliation(s)
- Lucas Bayonés
- Instituto de Fisiología, Biología Molecular y Neurociencias, CONICET, Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires 1428, Argentina
| | - María José Guerra-Fernández
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña 1111, Valparaíso 2360102, Chile
| | - Fernando Hinostroza
- Centro de Investigación de Estudios Avanzados del Maule (CIEAM), Vicerrectoría de Investigación y Postgrado, Universidad Católica del Maule, Talca 3460000, Chile
- Centro de Investigación en Neuropsicología y Neurociencias Cognitivas (CINPSI Neurocog), Facultad de Ciencias de la Salud, Universidad Católica del Maule, Talca 3460000, Chile
| | - Ximena Báez-Matus
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña 1111, Valparaíso 2360102, Chile
| | - Jacqueline Vásquez-Navarrete
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña 1111, Valparaíso 2360102, Chile
| | - Luciana I. Gallo
- Instituto de Fisiología, Biología Molecular y Neurociencias, CONICET, Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires 1428, Argentina
| | - Sergio Parra
- Instituto de Fisiología Celular—Neurociencias, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
| | - Agustín D. Martínez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña 1111, Valparaíso 2360102, Chile
| | - Arlek González-Jamett
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña 1111, Valparaíso 2360102, Chile
- Escuela de Química y Farmacia, Facultad de Farmacia, Universidad de Valparaíso, Valparaíso 2360102, Chile
| | - Fernando D. Marengo
- Instituto de Fisiología, Biología Molecular y Neurociencias, CONICET, Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires 1428, Argentina
- Correspondence: (F.D.M.); (A.M.C.)
| | - Ana M. Cárdenas
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña 1111, Valparaíso 2360102, Chile
- Correspondence: (F.D.M.); (A.M.C.)
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Knudsen JR, Madsen AB, Li Z, Andersen NR, Schjerling P, Jensen TE. Gene deletion of γ-actin impairs insulin-stimulated skeletal muscle glucose uptake in growing mice but not in mature adult mice. Physiol Rep 2022; 10:e15183. [PMID: 35224890 PMCID: PMC8882697 DOI: 10.14814/phy2.15183] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 12/16/2021] [Accepted: 12/17/2021] [Indexed: 04/14/2023] Open
Abstract
The cortical cytoskeleton, consisting of the cytoplasmic actin isoforms β and/or γ-actin, has been implicated in insulin-stimulated GLUT4 translocation and glucose uptake in muscle and adipose cell culture. Furthermore, transgenic inhibition of multiple actin-regulating proteins in muscle inhibits insulin-stimulated muscle glucose uptake. The current study tested if γ-actin was required for insulin-stimulated glucose uptake in mouse skeletal muscle. Based on our previously reported age-dependent phenotype in muscle-specific β-actin gene deletion (-/- ) mice, we included cohorts of growing 8-14 weeks old and mature 18-32 weeks old muscle-specific γ-actin-/- mice or wild-type littermates. In growing mice, insulin significantly increased the glucose uptake in slow-twitch oxidative soleus and fast-twitch glycolytic EDL muscles from wild-type mice, but not γ-actin-/- . In relative values, the maximal insulin-stimulated glucose uptake was reduced by ~50% in soleus and by ~70% in EDL muscles from growing γ-actin-/- mice compared to growing wild-type mice. In contrast, the insulin-stimulated glucose uptake responses in mature adult γ-actin-/- soleus and EDL muscles were indistinguishable from the responses in wild-type muscles. Mature adult insulin-stimulated phosphorylations on Akt, p70S6K, and ULK1 were not significantly affected by genotype. Hence, insulin-stimulated muscle glucose uptake shows an age-dependent impairment in young growing but not in fully grown γ-actin-/- mice, bearing phenotypic resemblance to β-actin-/- mice. Overall, γ-actin does not appear required for insulin-stimulated muscle glucose uptake in adulthood. Furthermore, our data emphasize the need to consider the rapid growth of young mice as a potential confounder in transgenic mouse phenotyping studies.
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Affiliation(s)
- Jonas R. Knudsen
- Section for Molecular PhysiologyDepartment of Nutrition, Exercise and SportsUniversity of CopenhagenCopenhagenDenmark
| | - Agnete B. Madsen
- Section for Molecular PhysiologyDepartment of Nutrition, Exercise and SportsUniversity of CopenhagenCopenhagenDenmark
| | - Zhencheng Li
- Section for Molecular PhysiologyDepartment of Nutrition, Exercise and SportsUniversity of CopenhagenCopenhagenDenmark
| | - Nicoline R. Andersen
- Section for Molecular PhysiologyDepartment of Nutrition, Exercise and SportsUniversity of CopenhagenCopenhagenDenmark
| | - Peter Schjerling
- Department of Orthopedic Surgery MInstitute of Sports Medicine CopenhagenBispebjerg HospitalCopenhagenDenmark
| | - Thomas E. Jensen
- Section for Molecular PhysiologyDepartment of Nutrition, Exercise and SportsUniversity of CopenhagenCopenhagenDenmark
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5
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Li J, Knudsen JR, Henriquez-Olguin C, Li Z, Birk JB, Persson KW, Hellsten Y, Offergeld A, Jarassier W, Le Grand F, Schjerling P, Wojtaszewski JFP, Jensen TE. AXIN1 knockout does not alter AMPK/mTORC1 regulation and glucose metabolism in mouse skeletal muscle. J Physiol 2021; 599:3081-3100. [PMID: 33913171 DOI: 10.1113/jp281187] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 04/20/2021] [Indexed: 01/15/2023] Open
Abstract
KEY POINTS Tamoxifen-inducible skeletal muscle-specific AXIN1 knockout (AXIN1 imKO) in mouse does not affect whole-body energy substrate metabolism. AXIN1 imKO does not affect AICAR or insulin-stimulated glucose uptake in adult skeletal muscle. AXIN1 imKO does not affect adult skeletal muscle AMPK or mTORC1 signalling during AICAR/insulin/amino acid incubation, contraction and exercise. During exercise, α2/β2/γ3AMPK and AMP/ATP ratio show greater increases in AXIN1 imKO than wild-type in gastrocnemius muscle. ABSTRACT AXIN1 is a scaffold protein known to interact with >20 proteins in signal transduction pathways regulating cellular development and function. Recently, AXIN1 was proposed to assemble a protein complex essential to catabolic-anabolic transition by coordinating AMPK activation and inactivation of mTORC1 and to regulate glucose uptake-stimulation by both AMPK and insulin. To investigate whether AXIN1 is permissive for adult skeletal muscle function, a phenotypic in vivo and ex vivo characterization of tamoxifen-inducible skeletal muscle-specific AXIN1 knockout (AXIN1 imKO) mice was conducted. AXIN1 imKO did not influence AMPK/mTORC1 signalling or glucose uptake stimulation at rest or in response to different exercise/contraction protocols, pharmacological AMPK activation, insulin or amino acids stimulation. The only genotypic difference observed was in exercising gastrocnemius muscle, where AXIN1 imKO displayed elevated α2/β2/γ3 AMPK activity and AMP/ATP ratio compared to wild-type mice. Our work shows that AXIN1 imKO generally does not affect skeletal muscle AMPK/mTORC1 signalling and glucose metabolism, probably due to functional redundancy of its homologue AXIN2.
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Affiliation(s)
- Jingwen Li
- Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Jonas R Knudsen
- Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark.,Microsystems Laboratory 2, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Carlos Henriquez-Olguin
- Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Zhencheng Li
- Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Jesper B Birk
- Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Kaspar W Persson
- Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Ylva Hellsten
- Section for Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Anika Offergeld
- School of Bioscience, Cardiff University, Cardiff, CF10 3AX, UK
| | - William Jarassier
- Institut NeuroMyoGène, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U1217, Lyon, 69008, France
| | - Fabien Le Grand
- Institut NeuroMyoGène, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U1217, Lyon, 69008, France
| | - Peter Schjerling
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery M, Bispebjerg Hospital, Copenhagen, Denmark
| | - Jørgen F P Wojtaszewski
- Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Thomas E Jensen
- Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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Abstract
As the principal tissue for insulin-stimulated glucose disposal, skeletal muscle is a primary driver of whole-body glycemic control. Skeletal muscle also uniquely responds to muscle contraction or exercise with increased sensitivity to subsequent insulin stimulation. Insulin's dominating control of glucose metabolism is orchestrated by complex and highly regulated signaling cascades that elicit diverse and unique effects on skeletal muscle. We discuss the discoveries that have led to our current understanding of how insulin promotes glucose uptake in muscle. We also touch upon insulin access to muscle, and insulin signaling toward glycogen, lipid, and protein metabolism. We draw from human and rodent studies in vivo, isolated muscle preparations, and muscle cell cultures to home in on the molecular, biophysical, and structural elements mediating these responses. Finally, we offer some perspective on molecular defects that potentially underlie the failure of muscle to take up glucose efficiently during obesity and type 2 diabetes.
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Lechuga S, Naydenov NG, Feygin A, Cruise M, Ervasti JM, Ivanov AI. Loss of β-Cytoplasmic Actin in the Intestinal Epithelium Increases Gut Barrier Permeability in vivo and Exaggerates the Severity of Experimental Colitis. Front Cell Dev Biol 2020; 8:588836. [PMID: 33195251 PMCID: PMC7644907 DOI: 10.3389/fcell.2020.588836] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 10/06/2020] [Indexed: 12/21/2022] Open
Abstract
Intestinal epithelial barrier is critical for the maintenance of normal gut homeostasis and disruption of this barrier may trigger or exaggerate mucosal inflammation. The actin cytoskeleton is a key regulator of barrier structure and function, controlling the assembly and permeability of epithelial adherens and tight junctions. Epithelial cells express two actin isoforms: a β-cytoplasmic actin and γ-cytoplasmic actin. Our previous in vitro studies demonstrated that these actin isoforms play distinctive roles in establishing the intestinal epithelial barrier, by controlling the organization of different junctional complexes. It remains unknown, whether β-actin and γ-actin have unique or redundant functions in regulating the gut barrier in vivo. To address this question, we selectively knocked out β-actin expression in mouse intestinal epithelium. Mice with intestinal epithelial knockout of β-actin do not display gastrointestinal abnormalities or gross alterations of colonic mucosal architecture. This could be due to compensatory upregulation of γ-actin expression. Despite such compensation, β-actin knockout mice demonstrate increased intestinal permeability. Furthermore, these animals show more severe clinical symptoms during dextran sodium sulfate induced colitis, compared to control littermates. Such exaggerated colitis is associated with the higher expression of inflammatory cytokines, increased macrophage infiltration in the gut, and accelerated mucosal cell death. Consistently, intestinal organoids generated from β-actin knockout mice are more sensitive to tumor necrosis factor induced cell death, ex vivo. Overall, our data suggests that β-actin functions as an essential regulator of gut barrier integrity in vivo, and plays a tissue protective role during mucosal injury and inflammation.
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Affiliation(s)
- Susana Lechuga
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, United States
| | - Nayden G Naydenov
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, United States
| | - Alex Feygin
- School of Nursing, Virginia Commonwealth University School of Nursing, Richmond, VA, United States
| | - Michael Cruise
- Department of Pathology, Cleveland Clinic Foundation, Cleveland, OH, United States
| | - James M Ervasti
- Department of Biochemistry and Molecular Biology, University of Minnesota Medical School, Minneapolis, MN, United States
| | - Andrei I Ivanov
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, United States
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Masson SWC, Sorrenson B, Shepherd PR, Merry TL. β-catenin regulates muscle glucose transport via actin remodelling and M-cadherin binding. Mol Metab 2020; 42:101091. [PMID: 33011305 PMCID: PMC7568189 DOI: 10.1016/j.molmet.2020.101091] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 09/17/2020] [Accepted: 09/24/2020] [Indexed: 12/13/2022] Open
Abstract
Objective Skeletal muscle glucose disposal following a meal is mediated through insulin-stimulated movement of the GLUT4-containing vesicles to the cell surface. The highly conserved scaffold-protein β-catenin is an emerging regulator of vesicle trafficking in other tissues. Here, we investigated the involvement of β-catenin in skeletal muscle insulin-stimulated glucose transport. Methods Glucose homeostasis and transport was investigated in inducible muscle specific β-catenin knockout (BCAT-mKO) mice. The effect of β-catenin deletion and mutation of β-catenin serine 552 on signal transduction, glucose uptake and protein–protein interactions were determined in L6-G4-myc cells, and β-catenin insulin-responsive binding partners were identified via immunoprecipitation coupled to label-free proteomics. Results Skeletal muscle specific deletion of β-catenin impaired whole-body insulin sensitivity and insulin-stimulated glucose uptake into muscle independent of canonical Wnt signalling. In response to insulin, β-catenin was phosphorylated at serine 552 in an Akt-dependent manner, and in L6-G4-myc cells, mutation of β-cateninS552 impaired insulin-induced actin-polymerisation, resulting in attenuated insulin-induced glucose transport and GLUT4 translocation. β-catenin was found to interact with M-cadherin in an insulin-dependent β-cateninS552-phosphorylation dependent manner, and loss of M-cadherin in L6-G4-myc cells attenuated insulin-induced actin-polymerisation and glucose transport. Conclusions Our data suggest that β-catenin is a novel mediator of glucose transport in skeletal muscle and may contribute to insulin-induced actin-cytoskeleton remodelling to support GLUT4 translocation. Deletion of β-catenin from the muscles of adult mice attenuates skeletal muscle glucose uptake. Insulin stimulates phosphorylation of β-cateninS552 by a mechanism involving Akt, and this is required for insulin's effects on both GLUT4 trafficking and actin remodelling. Insulin promotes β-catenin/M-cadherin binding, to support cortical actin remodelling associated with GLUT4 translocation.
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Affiliation(s)
- Stewart W C Masson
- Discipline of Nutrition, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
| | - Brie Sorrenson
- Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Peter R Shepherd
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand; Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Troy L Merry
- Discipline of Nutrition, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand.
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9
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Ogasawara R, Knudsen JR, Li J, Ato S, Jensen TE. Rapamycin and mTORC2 inhibition synergistically reduce contraction-stimulated muscle protein synthesis. J Physiol 2020; 598:5453-5466. [PMID: 32893874 DOI: 10.1113/jp280528] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 08/24/2020] [Indexed: 12/15/2022] Open
Abstract
KEY POINTS Muscle contractions increase protein synthesis in a mechanistic target of rapamycin (mTOR)-dependent manner, yet it is unclear which/how mTOR complexes regulate muscle protein synthesis. We investigated the requirement of mTOR Complex 2 (mTORC2) in contraction-stimulated muscle protein synthesis. mTORC2 inhibition by muscle-specific Rictor knockout (Rictor mKO) did not prevent contraction-induced muscle protein synthesis. Rapamycin prevented contraction-induced muscle protein synthesis in Rictor mKO but not wild-type mice. ABSTRACT Protein synthesis increases following muscle contractions. Previous studies have shown that inhibition of the mechanistic target of rapamycin complex 1 (mTORC1) suppresses the early but not late muscle protein synthesis response, while inhibition of both mTORC1 and mTORC2 abolishes the two effects. Therefore, we hypothesized that mTORC2 regulates muscle protein synthesis following muscle contractions. To test this, we investigated the effect of mTORC2 inhibition by mouse muscle-specific Rictor knockout (Rictor mKO) on muscle protein synthesis 3 h after contraction. The right gastrocnemius muscles of Rictor mKO and wild-type (WT) mice were isometrically contracted using percutaneous electrical stimulation, while the left gastrocnemius muscles served as controls. Vehicle or the mTORC1 inhibitor rapamycin (1.5 mg/kg) was injected intraperitoneally 1 h before contraction. Treatment of WT mice with rapamycin and Rictor mKO lowered protein synthesis in general, but the response to contractions was intact 3 h after contractions in both conditions. Rapamycin treatment in Rictor mKO mice prevented contraction-stimulated muscle protein synthesis. Notably, signalling traditionally associated with mTORC1 was increased by muscle contractions despite rapamycin treatment. In rapamycin-treated Rictor mKO mice, the same mTORC1 signalling was blocked following contractions. Our results indicate that although neither rapamycin-sensitive mTOR/mTORC1 nor mTORC2 is necessary for contraction-induced muscle protein synthesis, combined inhibition of rapamycin-sensitive mTOR/mTORC1 and mTORC2 synergistically inhibits contraction-induced muscle protein synthesis.
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Affiliation(s)
- Riki Ogasawara
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya, Japan.,Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
| | - Jonas R Knudsen
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark.,Laboratory of Microsystems 2, École Polytecgnique Fédérale de Lausanne, Switzerland
| | - Jingwen Li
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
| | - Satoru Ato
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya, Japan
| | - Thomas E Jensen
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
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10
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Henríquez-Olguín C, Boronat S, Cabello-Verrugio C, Jaimovich E, Hidalgo E, Jensen TE. The Emerging Roles of Nicotinamide Adenine Dinucleotide Phosphate Oxidase 2 in Skeletal Muscle Redox Signaling and Metabolism. Antioxid Redox Signal 2019; 31:1371-1410. [PMID: 31588777 PMCID: PMC6859696 DOI: 10.1089/ars.2018.7678] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Significance: Skeletal muscle is a crucial tissue to whole-body locomotion and metabolic health. Reactive oxygen species (ROS) have emerged as intracellular messengers participating in both physiological and pathological adaptations in skeletal muscle. A complex interplay between ROS-producing enzymes and antioxidant networks exists in different subcellular compartments of mature skeletal muscle. Recent evidence suggests that nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOXs) are a major source of contraction- and insulin-stimulated oxidants production, but they may paradoxically also contribute to muscle insulin resistance and atrophy. Recent Advances: Pharmacological and molecular biological tools, including redox-sensitive probes and transgenic mouse models, have generated novel insights into compartmentalized redox signaling and suggested that NOX2 contributes to redox control of skeletal muscle metabolism. Critical Issues: Major outstanding questions in skeletal muscle include where NOX2 activation occurs under different conditions in health and disease, how NOX2 activation is regulated, how superoxide/hydrogen peroxide generated by NOX2 reaches the cytosol, what the signaling mediators are downstream of NOX2, and the role of NOX2 for different physiological and pathophysiological processes. Future Directions: Future research should utilize and expand the current redox-signaling toolbox to clarify the NOX2-dependent mechanisms in skeletal muscle and determine whether the proposed functions of NOX2 in cells and animal models are conserved into humans.
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Affiliation(s)
- Carlos Henríquez-Olguín
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports (NEXS), Faculty of Science, University of Copenhagen, Copenhagen, Denmark.,Muscle Cell Physiology Laboratory, Center for Exercise, Metabolism, and Cancer, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
| | - Susanna Boronat
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona, Spain
| | - Claudio Cabello-Verrugio
- Laboratory of Muscle Pathology, Fragility and Aging, Department of Biological Sciences, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile.,Millennium Institute on Immunology and Immunotherapy, Santiago, Chile.,Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Universidad de Santiago de Chile, Santiago, Chile
| | - Enrique Jaimovich
- Muscle Cell Physiology Laboratory, Center for Exercise, Metabolism, and Cancer, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
| | - Elena Hidalgo
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona, Spain
| | - Thomas E Jensen
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports (NEXS), Faculty of Science, University of Copenhagen, Copenhagen, Denmark
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11
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Henríquez-Olguin C, Knudsen JR, Raun SH, Li Z, Dalbram E, Treebak JT, Sylow L, Holmdahl R, Richter EA, Jaimovich E, Jensen TE. Cytosolic ROS production by NADPH oxidase 2 regulates muscle glucose uptake during exercise. Nat Commun 2019; 10:4623. [PMID: 31604916 PMCID: PMC6789013 DOI: 10.1038/s41467-019-12523-9] [Citation(s) in RCA: 115] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 09/11/2019] [Indexed: 12/11/2022] Open
Abstract
Reactive oxygen species (ROS) act as intracellular compartmentalized second messengers, mediating metabolic stress-adaptation. In skeletal muscle fibers, ROS have been suggested to stimulate glucose transporter 4 (GLUT4)-dependent glucose transport during artificially evoked contraction ex vivo, but whether myocellular ROS production is stimulated by in vivo exercise to control metabolism is unclear. Here, we combined exercise in humans and mice with fluorescent dyes, genetically-encoded biosensors, and NADPH oxidase 2 (NOX2) loss-of-function models to demonstrate that NOX2 is the main source of cytosolic ROS during moderate-intensity exercise in skeletal muscle. Furthermore, two NOX2 loss-of-function mouse models lacking either p47phox or Rac1 presented striking phenotypic similarities, including greatly reduced exercise-stimulated glucose uptake and GLUT4 translocation. These findings indicate that NOX2 is a major myocellular ROS source, regulating glucose transport capacity during moderate-intensity exercise.
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Affiliation(s)
- Carlos Henríquez-Olguin
- Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen, Denmark.,Center for Exercise, Metabolism and Cancer, ICBM, Universidad de Chile, 8380453, Santiago, Chile
| | - Jonas R Knudsen
- Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen, Denmark
| | - Steffen H Raun
- Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen, Denmark
| | - Zhencheng Li
- Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen, Denmark
| | - Emilie Dalbram
- Novo Nordisk Foundation Center for Basic Metabolic Research, Integrative Metabolism and Environmental Influence, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3A, 2200, Copenhagen, Denmark
| | - Jonas T Treebak
- Novo Nordisk Foundation Center for Basic Metabolic Research, Integrative Metabolism and Environmental Influence, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3A, 2200, Copenhagen, Denmark
| | - Lykke Sylow
- Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen, Denmark
| | - Rikard Holmdahl
- Section for Medical Inflammation Research, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Solnavägen 9, 171 65, Solna, Sweden
| | - Erik A Richter
- Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen, Denmark
| | - Enrique Jaimovich
- Center for Exercise, Metabolism and Cancer, ICBM, Universidad de Chile, 8380453, Santiago, Chile
| | - Thomas E Jensen
- Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen, Denmark.
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12
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Martins VF, Dent JR, Svensson K, Tahvilian S, Begur M, Lakkaraju S, Buckner EH, LaBarge SA, Hetrick B, McCurdy CE, Schenk S. Germline or inducible knockout of p300 or CBP in skeletal muscle does not alter insulin sensitivity. Am J Physiol Endocrinol Metab 2019; 316:E1024-E1035. [PMID: 30888860 PMCID: PMC6620570 DOI: 10.1152/ajpendo.00497.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Akt is a critical mediator of insulin-stimulated glucose uptake in skeletal muscle. The acetyltransferases, E1A binding protein p300 (p300) and cAMP response element-binding protein binding protein (CBP) are phosphorylated and activated by Akt, and p300/CBP can acetylate and inactivate Akt, thus giving rise to a possible Akt-p300/CBP axis. Our objective was to determine the importance of p300 and CBP to skeletal muscle insulin sensitivity. We used Cre-LoxP methodology to generate mice with germline [muscle creatine kinase promoter (P-MCK and C-MCK)] or inducible [tamoxifen-activated, human skeletal actin promoter (P-iHSA and C-iHSA)] knockout of p300 or CBP. A subset of P-MCK and C-MCK mice were switched to a calorie-restriction diet (60% of ad libitum intake) or high-fat diet at 10 wk of age. For P-iHSA and C-iHSA mice, knockout was induced at 10 wk of age. At 13-15 wk of age, we measured whole-body energy expenditure, oral glucose tolerance, and/or ex vivo skeletal muscle insulin sensitivity. Although p300 and CBP protein abundance and mRNA expression were reduced 55%-90% in p300 and CBP knockout mice, there were no genotype differences in energy expenditure or fasting glucose and insulin concentrations. Moreover, neither loss of p300 or CBP impacted oral glucose tolerance or skeletal muscle insulin sensitivity, nor did their loss impact alterations in these parameters in response to a calorie restriction or high-fat diet. Muscle-specific loss of either p300 or CBP, be it germline or in adulthood, does not impact energy expenditure, glucose tolerance, or skeletal muscle insulin action.
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Affiliation(s)
- Vitor F Martins
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, California
| | - Jessica R Dent
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
| | - Kristoffer Svensson
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
| | - Shahriar Tahvilian
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
| | - Maedha Begur
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
| | - Shivani Lakkaraju
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
| | - Elisa H Buckner
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
| | - Samuel A LaBarge
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
| | - Byron Hetrick
- Department of Human Physiology, University of Oregon , Eugene, Oregon
| | - Carrie E McCurdy
- Department of Human Physiology, University of Oregon , Eugene, Oregon
| | - Simon Schenk
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, California
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13
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Møller LLV, Klip A, Sylow L. Rho GTPases-Emerging Regulators of Glucose Homeostasis and Metabolic Health. Cells 2019; 8:E434. [PMID: 31075957 PMCID: PMC6562660 DOI: 10.3390/cells8050434] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 05/02/2019] [Accepted: 05/06/2019] [Indexed: 12/11/2022] Open
Abstract
Rho guanosine triphosphatases (GTPases) are key regulators in a number of cellular functions, including actin cytoskeleton remodeling and vesicle traffic. Traditionally, Rho GTPases are studied because of their function in cell migration and cancer, while their roles in metabolism are less documented. However, emerging evidence implicates Rho GTPases as regulators of processes of crucial importance for maintaining metabolic homeostasis. Thus, the time is now ripe for reviewing Rho GTPases in the context of metabolic health. Rho GTPase-mediated key processes include the release of insulin from pancreatic β cells, glucose uptake into skeletal muscle and adipose tissue, and muscle mass regulation. Through the current review, we cast light on the important roles of Rho GTPases in skeletal muscle, adipose tissue, and the pancreas and discuss the proposed mechanisms by which Rho GTPases act to regulate glucose metabolism in health and disease. We also describe challenges and goals for future research.
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Affiliation(s)
- Lisbeth Liliendal Valbjørn Møller
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, 2100 Copenhagen Oe, Denmark.
| | - Amira Klip
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada.
| | - Lykke Sylow
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, 2100 Copenhagen Oe, Denmark.
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14
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Knudsen JR, Henriquez-Olguin C, Li Z, Jensen TE. Electroporated GLUT4-7myc-GFP detects in vivo glucose transporter 4 translocation in skeletal muscle without discernible changes in GFP patterns. Exp Physiol 2019; 104:704-714. [PMID: 30710396 DOI: 10.1113/ep087545] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 02/01/2019] [Indexed: 12/22/2022]
Abstract
NEW FINDINGS What is the central question of this study? Resolving the mechanism(s) leading to glucose transporter 4 (GLUT4) translocation to the muscle surface membrane has great therapeutic potential. However, the measurement of GLUT4 translocation is technically challenging. Here, we asked whether electroporation of GLUT4-7myc-GFP into skeletal muscle could be used as a tool to study GLUT4 translocation in vivo. What is the main finding and its importance? By acutely inducing GLUT4-7myc-GFP expression in skeletal muscle, we verified that in vivo exercise and AICAR stimulation increased the GLUT4 presence in the sarcolemma measured as myc signal. Importantly, the increased myc signal in the sarcolemma was not accompanied by major visual changes in the distribution of the GFP signal. ABSTRACT Insulin and exercise lead to translocation of the glucose transporter 4 (GLUT4) to the surface membrane of skeletal muscle fibres. This process is pivotal for facilitating glucose uptake into skeletal muscle. To study this, a robust assay is needed to measure the translocation of GLUT4 in adult skeletal muscle directly. Here, we aimed to validate a simple GLUT4 translocation assay using a genetically encoded biosensor in mouse skeletal muscle. We transfected GLUT4-7myc-GFP into mouse muscle to study live GLUT4 movement and to evaluate GLUT4 insertion in the muscle surface membrane after in vivo running exercise and pharmacological activation of AMP-activated protein kinase (AMPK). Transfection led to expression of GLUT4-7myc-GFP that was dynamic in live flexor digitorum brevis fibres and which, upon insulin stimulation, exposed the myc epitope extracellularly. Running exercise, in addition to AMPK activation by 5-aminoimidazole-4-carboxamide ribonucleotide, induced ∼125 and ∼100% increase, respectively, in extracellularly exposure of GLUT4 in the surface membrane of tibialis anterior muscle. Interestingly, the clear increase in surface-exposed GLUT4 content induced by insulin, exercise or AMPK activation was not accompanied by any discernible reorganization of the GLUT4-GFP signal. In conclusion, we provide a detailed description of an easy-to-use translocation assay to study GLUT4 accumulation at the surface membrane induced by exercise and exercise-mimicking stimuli. Notably, our analyses revealed that increased GLUT4 surface membrane accumulation was not accompanied by a discernible change in the GLUT4 localization pattern.
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Affiliation(s)
- Jonas Roland Knudsen
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Carlos Henriquez-Olguin
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Zhencheng Li
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Elbenhardt Jensen
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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15
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Marko DM, Shamshoum H. Rac1 supports muscle glucose uptake independently of Akt. J Physiol 2018; 596:4815-4816. [PMID: 30160315 DOI: 10.1113/jp276851] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Daniel M Marko
- Department of Health Sciences, Brock University, St Catharines, ON, L2S 3A1, Canada
| | - Hesham Shamshoum
- Department of Health Sciences, Brock University, St Catharines, ON, L2S 3A1, Canada
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16
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Raun SH, Ali M, Kjøbsted R, Møller LLV, Federspiel MA, Richter EA, Jensen TE, Sylow L. Rac1 muscle knockout exacerbates the detrimental effect of high-fat diet on insulin-stimulated muscle glucose uptake independently of Akt. J Physiol 2018; 596:2283-2299. [PMID: 29749029 DOI: 10.1113/jp275602] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 03/19/2018] [Indexed: 12/17/2022] Open
Abstract
KEY POINTS The actin cytoskeleton regulating GTPase, Rac1, is a novel player in insulin-stimulated glucose uptake in muscle in vivo. High-fat diet (HFD) exacerbates muscle insulin resistance in Rac1 muscle knockout (mKO) mice. Muscle Rac1 KO protects against HFD-induced insulin resistance in fat tissue indicating tissue cross-talk. A fatty diet markedly reduces insulin clearance in mice. ABSTRACT Insulin resistance and perturbations in glucose metabolism underpin common lifestyle diseases such as type 2 diabetes and obesity. Insulin resistance in muscle is characterized by compromised activity of the GTPase, Ras-related C3 Botulinum toxin substrate 1 (Rac1), yet the role of Rac1 in insulin-stimulated glucose uptake in vivo and diet-induced insulin resistance is unknown. Inducible muscle-specific Rac1 knockout (Rac1 mKO) and wild type (WT) littermate mice were either fed a chow or a 60% high-fat diet (HFD). Insulin-stimulated 2-deoxy-glucose uptake, intracellular signalling, protein expression, substrate utilization, and glucose and insulin tolerance were assessed. In chow-fed mice, in vivo insulin-stimulated glucose uptake was reduced in triceps, soleus and gastrocnemius muscles from Rac1 mKO mice. HFD-induced whole body insulin resistance was exacerbated by the lack of muscle Rac1 and glucose uptake was reduced in all muscles, except for soleus. Muscle Akt (also known as protein kinase B) signalling was unaffected by diet or genotype. In adipose tissue, Rac1 mKO mice were protected from HFD-induced insulin resistance (with respect to both glucose uptake and phosphorylated-Akt), rendering their whole body glucose tolerance comparable to WT mice on HFD. Our findings show that lack of Rac1 exacerbates HFD-induced insulin resistance in skeletal muscle. Whole body glucose tolerance, however, was largely unaffected in Rac1 mKO mice, likely due to improved insulin-stimulated glucose uptake in adipose tissue. We conclude that lack of Rac1 in the context of obesity is detrimental to insulin-stimulated muscle glucose uptake in muscle independently of Akt signalling.
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Affiliation(s)
- Steffen H Raun
- Molecular Physiology Group, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Universitetsparken 13, Copenhagen, 2100, Denmark
| | - Mona Ali
- Molecular Physiology Group, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Universitetsparken 13, Copenhagen, 2100, Denmark
| | - Rasmus Kjøbsted
- Molecular Physiology Group, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Universitetsparken 13, Copenhagen, 2100, Denmark
| | - Lisbeth L V Møller
- Molecular Physiology Group, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Universitetsparken 13, Copenhagen, 2100, Denmark
| | - Morten A Federspiel
- Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Erik A Richter
- Molecular Physiology Group, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Universitetsparken 13, Copenhagen, 2100, Denmark
| | - Thomas E Jensen
- Molecular Physiology Group, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Universitetsparken 13, Copenhagen, 2100, Denmark
| | - Lykke Sylow
- Molecular Physiology Group, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Universitetsparken 13, Copenhagen, 2100, Denmark
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