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Klip A, De Bock K, Bilan PJ, Richter EA. Transcellular Barriers to Glucose Delivery in the Body. Annu Rev Physiol 2024; 86:149-173. [PMID: 38345907 DOI: 10.1146/annurev-physiol-042022-031657] [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] [Indexed: 02/15/2024]
Abstract
Glucose is the universal fuel of most mammalian cells, and it is largely replenished through dietary intake. Glucose availability to tissues is paramount for the maintenance of homeostatic energetics and, hence, supply should match demand by the consuming organs. In its journey through the body, glucose encounters cellular barriers for transit at the levels of the absorbing intestinal epithelial wall, the renal epithelium mediating glucose reabsorption, and the tight capillary endothelia (especially in the brain). Glucose transiting through these cellular barriers must escape degradation to ensure optimal glucose delivery to the bloodstream or tissues. The liver, which stores glycogen and generates glucose de novo, must similarly be able to release it intact to the circulation. We present the most up-to-date knowledge on glucose handling by the gut, liver, brain endothelium, and kidney, and discuss underlying molecular mechanisms and open questions. Diseases associated with defects in glucose delivery and homeostasis are also briefly addressed. We propose that the universal problem of sparing glucose from catabolism in favor of translocation across the barriers posed by epithelia and endothelia is resolved through common mechanisms involving glucose transfer to the endoplasmic reticulum, from where glucose exits the cells via unconventional cellular mechanisms.
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Affiliation(s)
- Amira Klip
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada;
| | - Katrien De Bock
- Laboratory of Exercise and Health, Department of Health Sciences and Technology, Swiss Federal Institute of Technology (ETH), Zürich, Switzerland
| | - Philip J Bilan
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada;
| | - Erik A Richter
- The August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
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2
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Antoniak-Pietrynczak K, Zorena K, Jaskulak M, Hansdorfer-Korzon R, Koziński M. Effect of Manual Lymphatic Drainage on the Concentrations of Selected Adipokines, Cytokines, C-Reactive Protein and Parameters of Carbohydrate and Lipid Metabolism in Patients with Abnormal Body Mass Index: Focus on Markers of Obesity and Insulin Resistance. Int J Mol Sci 2023; 24:10338. [PMID: 37373485 DOI: 10.3390/ijms241210338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 06/15/2023] [Accepted: 06/16/2023] [Indexed: 06/29/2023] Open
Abstract
The aim of the study was to assess the impact of manual lymphatic drainage (MLD) on the parameters of carbohydrate metabolism, lipid metabolism and the level of selected adipokines and cytokines in people with abnormal body mass index (BMI). In addition, an attempt was made to assess the optimal cut-off values of serum concentrations of the biochemical parameters studied in identifying the risk of obesity and insulin resistance (IR). The study included 60 subjects who underwent 10 and 30 min long MLD sessions three times a week. The study group included 15 patients with a normal body mass index (group I; n = 15), overweight patients (group II; n = 15) and obese patients (group III; n = 10). The control group was IV; n = 20 subjects not undergoing MLD. Biochemical tests were carried out on all subjects at stage 0' (before MLD therapy) and at stage 1' (one month after MLD therapy). In the control group, the time between the sample collection at stage 0' and stage 1' was the same as in the study group. Our results showed that 10 MLD sessions may have a positive effect on the selected biochemical parameters, including insulin, 2h-PG, leptin and HOMA-IR values in normal weight and overweight patients. In addition, in the study group, the highest AUCROC values in identifying the risk of obesity were found for leptin (AUCROC = 82.79%; cut-off = 17.7 ng/mL; p = 0.00004), insulin (AUCROC = 81.51%; cut-off = 9.5 µIU/mL; p = 0.00009) and C-peptide (AUCROC = 80.68%; cut-off = 2.3 ng/mL; p = 0.0001) concentrations as well as for HOMA-IR values (AUCROC = 79.97%; cut-off = 1.8; p = 0.0002). When considering the risk of IR, we observed the highest diagnostic value for insulin (AUCROC = 93.05%; cut-off = 1.8 ng/mL; p = 0.053), which was followed by C-peptide (AUCROC = 89.35%; cut-off = 17.7 ng/mL; p = 0.000001), leptin (AUCROC = 79.76%; cut-off = 17.6 ng/mL; p = 0.0002) and total cholesterol (AUCROC = 77.31%; cut-off = 198 mg/dL; p = 0.0008). Our results indicate that MLD may have a positive effect on selected biochemical parameters, including insulin, 2h-PG, leptin and HOMA-IR, in normal weight and overweight patients. In addition, we successfully established optimal cut-off values for leptin in the assessment of obesity and insulin in the assessment of insulin resistance in patients with abnormal body mass index. Based on our findings, we hypothesize that MLD, when combined with caloric restriction and physical activity, may serve as an effective preventive intervention against the development of obesity and insulin resistance.
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Affiliation(s)
- Klaudia Antoniak-Pietrynczak
- Department of Immunobiology and Environment Microbiology, Medical University of Gdansk, Dębinki 7, 80-211 Gdansk, Poland
| | - Katarzyna Zorena
- Department of Immunobiology and Environment Microbiology, Medical University of Gdansk, Dębinki 7, 80-211 Gdansk, Poland
| | - Marta Jaskulak
- Department of Immunobiology and Environment Microbiology, Medical University of Gdansk, Dębinki 7, 80-211 Gdansk, Poland
| | - Rita Hansdorfer-Korzon
- Department of Physiotherapy, Medical University of Gdansk, Dębinki 7, 80-211 Gdansk, Poland
| | - Marek Koziński
- Department of Cardiology and Internal Diseases, Institute of Maritime and Tropical Medicine, Faculty of Health Sciences, Medical University of Gdansk, Powstania Styczniowego 9b, 81-519 Gdynia, Poland
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3
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Tokarz VL, Pereira RVS, Jaldin-Fincati JR, Mylvaganam S, Klip A. Junctional integrity and directional mobility of lymphatic endothelial cell monolayers are disrupted by saturated fatty acids. Mol Biol Cell 2023; 34:ar28. [PMID: 36735487 PMCID: PMC10092641 DOI: 10.1091/mbc.e22-08-0367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The lymphatic circulation regulates transfer of tissue fluid and immune cells toward the venous circulation. While obesity impairs lymphatic vessel function, the contribution of lymphatic endothelial cells (LEC) to metabolic disease phenotypes is poorly understood. LEC of lymphatic microvessels are in direct contact with the interstitial fluid, whose composition changes during the development of obesity, markedly by increases in saturated fatty acids. Palmitate, the most prevalent saturated fatty acid in lymph and blood, is detrimental to metabolism and function of diverse tissues, but its impact on LEC function is relatively unknown. Here, palmitate (but not its unsaturated counterpart palmitoleate) destabilized adherens junctions in human microvascular LEC in culture, visualized as changes in VE-cadherin, α-catenin, and β-catenin localization. Detachment of these proteins from cortical actin filaments was associated with abundant actomyosin stress fibers. The effects were Rho-associated protein kinase (ROCK)- and myosin-dependent, as inhibition with Y27632 or blebbistatin, respectively, prevented stress fiber accumulation and preserved junctions. Without functional junctions, palmitate-treated LEC failed to directionally migrate to close wounds in two dimensions and failed to form endothelial tubes in three dimensions. A reorganization of the lymphatic endothelial actin cytoskeleton may contribute to lymphatic dysfunction in obesity and could be considered as a therapeutic target.
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Affiliation(s)
- Victoria L Tokarz
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Physiology, University of Toronto, Toronto, ON M5S 1A1, Canada
| | - Rafaela V S Pereira
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | | | - Sivakami Mylvaganam
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A1, Canada
| | - Amira Klip
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Physiology, University of Toronto, Toronto, ON M5S 1A1, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A1, Canada.,Department of Paediatrics, University of Toronto, Toronto, ON M5S 1A1, Canada
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4
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Yazdani S, Bilan PJ, Jaldin-Fincati JR, Pang J, Ceban F, Saran E, Brumell JH, Freeman SA, Klip A. Dynamic glucose uptake, storage, and release by human microvascular endothelial cells. Mol Biol Cell 2022; 33:ar106. [PMID: 35921166 DOI: 10.1091/mbc.e22-04-0146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Endothelia determine blood-to-tissue solute delivery, yet glucose transit is poorly understood. To illuminate mechanisms, we tracked [3H]-2-deoxyglucose (2-DG) in human adipose-tissue microvascular endothelial cells. 2-DG uptake was largely facilitated by the glucose transporters GLUT1 and GLUT3. Once in the cytosol, >80% of 2-DG became phosphorylated and ∼20% incorporated into glycogen, suggesting that transported glucose is readily accessible to cytosolic enzymes. Interestingly, a fraction of intracellular 2-DG was released over time (15-20% over 30 min) with slower kinetics than for uptake, involving GLUT3. In contrast to intracellular 2-DG, the released 2-DG was largely unphosphorylated. Glucose release involved endoplasmic reticulum-resident translocases/phosphatases and was stimulated by adrenaline, consistent with participation of glycogenolysis and glucose dephosphorylation. Surprisingly, the fluorescent glucose derivative 2-NBD-glucose (2-NBDG) entered cells largely via fluid phase endocytosis and exited by recycling. 2-NBDG uptake was insensitive to GLUT1/GLUT3 inhibition, suggesting poor influx across membranes. 2-NBDG recycling, but not 2-DG efflux, was sensitive to N-ethyl maleimide. In sum, by utilizing radioactive and fluorescent glucose derivatives, we identified two parallel routes of entry: uptake into the cytosol through dedicated glucose transporters and endocytosis. This reveals the complex glucose handling by endothelial cells that may contribute to glucose delivery to tissues.
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Affiliation(s)
- Samaneh Yazdani
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON, Canada, M5G 0A4
| | - Philip J Bilan
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON, Canada, M5G 0A4
| | | | - Janice Pang
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON, Canada, M5G 0A4
| | - Felicia Ceban
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON, Canada, M5G 0A4
| | - Ekambir Saran
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON, Canada, M5G 0A4
| | - John H Brumell
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON, Canada, M5G 0A4.,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada, M5S 1A1.,Institute of Medical Science, University of Toronto, Toronto, ON, Canada, M5S 1A1.,SickKids IBD Centre, Hospital for Sick Children, Toronto, ON, Canada, M5G 0A4
| | - Spencer A Freeman
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON, Canada, M5G 0A4.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada, M5S 1A1
| | - Amira Klip
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON, Canada, M5G 0A4.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada, M5S 1A1.,Department of Paediatrics, University of Toronto, Toronto, ON, Canada, M5S 1A1.,Department of Physiology, University of Toronto, Toronto, ON, Canada, M5S 1A1
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5
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Khadria A, Paavola CD, Maslov K, Valenzuela FA, Sperry AE, Cox AL, Cao R, Shi J, Brown-Augsburger PL, Lozano E, Blankenship RL, Majumdar R, Bradley SA, Beals JM, Oladipupo SS, Wang LV. Photoacoustic imaging reveals mechanisms of rapid-acting insulin formulations dynamics at the injection site. Mol Metab 2022; 62:101522. [PMID: 35671972 PMCID: PMC9207296 DOI: 10.1016/j.molmet.2022.101522] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 05/20/2022] [Accepted: 05/24/2022] [Indexed: 01/25/2023] Open
Abstract
OBJECTIVE Ultra-rapid insulin formulations control postprandial hyperglycemia; however, inadequate understanding of injection site absorption mechanisms is limiting further advancement. We used photoacoustic imaging to investigate the injection site dynamics of dye-labeled insulin lispro in the Humalog® and Lyumjev® formulations using the murine ear cutaneous model and correlated it with results from unlabeled insulin lispro in pig subcutaneous injection model. METHODS We employed dual-wavelength optical-resolution photoacoustic microscopy to study the absorption and diffusion of the near-infrared dye-labeled insulin lispro in the Humalog and Lyumjev formulations in mouse ears. We mathematically modeled the experimental data to calculate the absorption rate constants and diffusion coefficients. We studied the pharmacokinetics of the unlabeled insulin lispro in both the Humalog and Lyumjev formulations as well as a formulation lacking both the zinc and phenolic preservative in pigs. The association state of insulin lispro in each of the formulations was characterized using SV-AUC and NMR spectroscopy. RESULTS Through experiments using murine and swine models, we show that the hexamer dissociation rate of insulin lispro is not the absorption rate-limiting step. We demonstrated that the excipients in the Lyumjev formulation produce local tissue expansion and speed both insulin diffusion and microvascular absorption. We also show that the diffusion of insulin lispro at the injection site drives its initial absorption; however, the rate at which the insulin lispro crosses the blood vessels is its overall absorption rate-limiting step. CONCLUSIONS This study provides insights into injection site dynamics of insulin lispro and the impact of formulation excipients. It also demonstrates photoacoustic microscopy as a promising tool for studying protein therapeutics. The results from this study address critical questions around the subcutaneous behavior of insulin lispro and the formulation excipients, which could be useful to make faster and better controlled insulin formulations in the future.
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Affiliation(s)
- Anjul Khadria
- Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Chad D Paavola
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, 46285, USA
| | - Konstantin Maslov
- Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Francisco A Valenzuela
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, 46285, USA
| | - Andrea E Sperry
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, 46285, USA
| | - Amy L Cox
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, 46285, USA
| | - Rui Cao
- Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Junhui Shi
- Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | | | - Emmanuel Lozano
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, 46285, USA
| | - Ross L Blankenship
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, 46285, USA
| | - Ranajoy Majumdar
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, 46285, USA
| | - Scott A Bradley
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, 46285, USA
| | - John M Beals
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Biotechnology Center, San Diego, CA, 92121, USA.
| | - Sunday S Oladipupo
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, 46285, USA.
| | - Lihong V Wang
- Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA; Caltech Optical Imaging Laboratory, Department of Electrical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA.
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6
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Ioannidou A, Fisher RM, Hagberg CE. The multifaceted roles of the adipose tissue vasculature. Obes Rev 2022; 23:e13403. [PMID: 34866318 DOI: 10.1111/obr.13403] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/28/2021] [Accepted: 11/04/2021] [Indexed: 12/30/2022]
Abstract
The prevalence of obesity and its associated pathologies continue to increase, which has led to a renewed interest in our major weight-regulating organ, the white adipose tissue. It has become clear that its development, expansion, and physiological function depend on proper crosstalk between each of its cellular constituents, with a central role for the vascular endothelium lining the blood vessels. Although first considered a mere barrier, the endothelium has emerged as a dynamic unit modulating many critical adipose tissue functions. It not only oversees the uptake of all nutrients to be stored in the adipocytes but also provides an important growth niche for adipocyte progenitors and regulates the expandability of the tissue during overfeeding and obesity. In this review, we describe the reciprocal relationship between endothelial cells, adipocytes, and obesity. We present recent studies that support an important role for endothelial cells as central mediators of many of the physiological and pathological functions of the adipose tissue and highlight several unknown aspects of adipose tissue vascular biology. This new perspective could present exciting opportunities to develop new therapeutic approaches against obesity-related pathologies and is thus of great interest in our increasingly obese society.
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Affiliation(s)
- Anna Ioannidou
- Division of Cardiovascular Medicine, Department of Medicine Solna, Karolinska Institutet, Solna, Sweden.,Center for Molecular Medicine, Karolinska Institutet, Solna, Sweden
| | - Rachel M Fisher
- Division of Cardiovascular Medicine, Department of Medicine Solna, Karolinska Institutet, Solna, Sweden.,Center for Molecular Medicine, Karolinska Institutet, Solna, Sweden
| | - Carolina E Hagberg
- Division of Cardiovascular Medicine, Department of Medicine Solna, Karolinska Institutet, Solna, Sweden.,Center for Molecular Medicine, Karolinska Institutet, Solna, Sweden
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7
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Williams IM, Wasserman DH. Capillary Endothelial Insulin Transport: The Rate-limiting Step for Insulin-stimulated Glucose Uptake. Endocrinology 2022; 163:6462374. [PMID: 34908124 PMCID: PMC8758342 DOI: 10.1210/endocr/bqab252] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Indexed: 11/19/2022]
Abstract
The rate-limiting step for skeletal muscle glucose uptake is transport from microcirculation to muscle interstitium. Capillary endothelium poses a barrier that delays the onset of muscle insulin action. Defining physiological barriers that control insulin access to interstitial space is difficult because of technical challenges that confront study of microscopic events in an integrated physiological system. Two physiological variables determine muscle insulin access. These are the number of perfused capillaries and the permeability of capillary walls to insulin. Disease states associated with capillary rarefaction are closely linked to insulin resistance. Insulin permeability through highly resistant capillary walls of muscle poses a significant barrier to insulin access. Insulin may traverse the endothelium through narrow intercellular junctions or vesicular trafficking across the endothelial cell. Insulin is large compared with intercellular junctions, making this an unlikely route. Transport by endothelial vesicular trafficking is likely the primary route of transit. Studies in vivo show movement of insulin is not insulin receptor dependent. This aligns with single-cell transcriptomics that show the insulin receptor is not expressed in muscle capillaries. Work in cultured endothelial cell lines suggest that insulin receptor activation is necessary for endothelial insulin transit. Controversies remain in the understanding of transendothelial insulin transit to muscle. These controversies closely align with experimental approaches. Control of circulating insulin accessibility to skeletal muscle is an area that remains ripe for discovery. Factors that impede insulin access to muscle may contribute to disease and factors that accelerate access may be of therapeutic value for insulin resistance.
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Affiliation(s)
- Ian M Williams
- Department of Molecular Physiology and Biophysics and Vanderbilt Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, TN 37232-0615, USA
| | - David H Wasserman
- Department of Molecular Physiology and Biophysics and Vanderbilt Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, TN 37232-0615, USA
- Correspondence: David H. Wasserman, PhD, Light Hall Rm. 702, Vanderbilt University, Nashville, TN 37232-0615, USA.
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8
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Koh HCE, Cao C, Mittendorfer B. Insulin Clearance in Obesity and Type 2 Diabetes. Int J Mol Sci 2022; 23:596. [PMID: 35054781 PMCID: PMC8776220 DOI: 10.3390/ijms23020596] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 01/02/2022] [Accepted: 01/03/2022] [Indexed: 02/06/2023] Open
Abstract
Plasma insulin clearance is an important determinant of plasma insulin concentration. In this review, we provide an overview of the factors that regulate insulin removal from plasma and discuss the interrelationships among plasma insulin clearance, excess adiposity, insulin sensitivity, and type 2 diabetes (T2D). We conclude with the perspective that the commonly observed lower insulin clearance rate in people with obesity, compared with lean people, is not a compensatory response to insulin resistance but occurs because insulin sensitivity and insulin clearance are mechanistically, directly linked. Furthermore, insulin clearance decreases postprandially because of the marked increase in insulin delivery to tissues that clear insulin. The commonly observed high postprandial insulin clearance in people with obesity and T2D likely results from the relatively low insulin secretion rate, not an impaired adaptation of tissues that clear insulin.
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Affiliation(s)
| | | | - Bettina Mittendorfer
- Center for Human Nutrition, Washington University School of Medicine, 660 S Euclid Ave, Campus Box 8031-14-0002, St. Louis, MO 63110, USA; (H.-C.E.K.); (C.C.)
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9
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Batra A, Latsko M, Portella AK, Silveira PP. Early adversity and insulin: neuroendocrine programming beyond glucocorticoids. Trends Endocrinol Metab 2021; 32:1031-1043. [PMID: 34635400 DOI: 10.1016/j.tem.2021.09.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 09/07/2021] [Accepted: 09/10/2021] [Indexed: 02/07/2023]
Abstract
Exposure to direct or contextual adversities during early life programs the functioning of the brain and other biological systems, contributing to the development of physical as well as mental health issues in the long term. While the role of glucocorticoids in mediating the outcomes of early adversity has been explored for many years, less attention has been given to insulin. Beyond its metabolic effects in the periphery, central insulin action affects synaptic plasticity, brain neurotransmission, and executive functions. Knowledge about the interactions between the peripheral metabolism and brain function from a developmental perspective can contribute to prevention and diagnosis programs, as well as early interventions for vulnerable populations.
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Affiliation(s)
- Aashita Batra
- Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada.
| | - Maeson Latsko
- Department of Psychiatry, McGill University, Montreal, QC, Canada; Healthy Brains for Healthy Lives, McGill University, Montreal, QC, Canada
| | - Andre Krumel Portella
- Ludmer Centre for Neuroinformatics and Mental Health, Douglas Mental Health University Institute, McGill University, Montreal, QC, Canada
| | - Patricia P Silveira
- Department of Psychiatry, McGill University, Montreal, QC, Canada; Ludmer Centre for Neuroinformatics and Mental Health, Douglas Mental Health University Institute, McGill University, Montreal, QC, Canada.
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10
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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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11
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Molecular Mechanisms of Glucocorticoid-Induced Insulin Resistance. Int J Mol Sci 2021; 22:ijms22020623. [PMID: 33435513 PMCID: PMC7827500 DOI: 10.3390/ijms22020623] [Citation(s) in RCA: 80] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/29/2020] [Accepted: 01/02/2021] [Indexed: 12/12/2022] Open
Abstract
Glucocorticoids (GCs) are steroids secreted by the adrenal cortex under the hypothalamic-pituitary-adrenal axis control, one of the major neuro-endocrine systems of the organism. These hormones are involved in tissue repair, immune stability, and metabolic processes, such as the regulation of carbohydrate, lipid, and protein metabolism. Globally, GCs are presented as ‘flight and fight’ hormones and, in that purpose, they are catabolic hormones required to mobilize storage to provide energy for the organism. If acute GC secretion allows fast metabolic adaptations to respond to danger, stress, or metabolic imbalance, long-term GC exposure arising from treatment or Cushing’s syndrome, progressively leads to insulin resistance and, in fine, cardiometabolic disorders. In this review, we briefly summarize the pharmacological actions of GC and metabolic dysregulations observed in patients exposed to an excess of GCs. Next, we describe in detail the molecular mechanisms underlying GC-induced insulin resistance in adipose tissue, liver, muscle, and to a lesser extent in gut, bone, and brain, mainly identified by numerous studies performed in animal models. Finally, we present the paradoxical effects of GCs on beta cell mass and insulin secretion by the pancreas with a specific focus on the direct and indirect (through insulin-sensitive organs) effects of GCs. Overall, a better knowledge of the specific action of GCs on several organs and their molecular targets may help foster the understanding of GCs’ side effects and design new drugs that possess therapeutic benefits without metabolic adverse effects.
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12
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Meijer RI, Barrett EJ. The Insulin Receptor Mediates Insulin's Early Plasma Clearance by Liver, Muscle, and Kidney. Biomedicines 2021; 9:biomedicines9010037. [PMID: 33466380 PMCID: PMC7824884 DOI: 10.3390/biomedicines9010037] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 01/02/2021] [Indexed: 11/16/2022] Open
Abstract
The role of the insulin receptor in mediating tissue-specific insulin clearance in vivo has not been reported. Using physiologic insulin doses, we measured the initial clearance rate (first 5 min) of intravenously injected ([125I]TyrA14)-insulin by muscle, liver, and kidney in healthy rats in the presence and absence of the insulin receptor blocker S961. We also tested whether 4 weeks of high-fat diet (HFD) affected the initial rate of insulin clearance. Pre-treatment with S961 for 60 min prior to administering labeled insulin raised plasma ([125I]TyrA14)insulin concentration approximately 5-fold (p < 0.001), demonstrating receptor dependency for plasma insulin clearance. Uptake by muscle (p < 0.01), liver (p < 0.05), and kidney (p < 0.001) were each inhibited by receptor blockade, undoubtedly contributing to the reduced plasma clearance. The initial plasma insulin clearance was not significantly affected by HFD, nor was muscle-specific clearance. However, HFD modestly decreased liver clearance (p = 0.056) while increasing renal clearance by >50% (p < 0.01), suggesting a significant role for renal insulin clearance in limiting the hyperinsulinemia that accompanies HFD. We conclude that the insulin receptor is a major mediator of initial insulin clearance from plasma and for its clearance by liver, kidney, and muscle. HFD feeding increases renal insulin clearance to limit systemic hyperinsulinemia.
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13
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Sanwal R, Khosraviani N, Advani SL, Advani A, Lee WL. The Endothelial Barrier Is not Rate-limiting to Insulin Action in the Myocardium of Male Mice. Endocrinology 2020; 161:5760840. [PMID: 32103251 PMCID: PMC7069687 DOI: 10.1210/endocr/bqaa029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 02/24/2020] [Indexed: 11/19/2022]
Abstract
To act on tissues, circulating insulin must perfuse the relevant organ and then leave the bloodstream by crossing the endothelium-a process known as insulin delivery. It has been postulated that the continuous endothelium is a rate-limiting barrier to insulin delivery but existing data are contradictory. This conflict is in part due to the limitations of current models, including the inability to maintain a constant blood pressure in animals and the absence of shear stress in cultured cells. We developed a murine cardiac ex vivo perfusion model that delivers insulin to the heart in situ at a constant flow. We hypothesized that if the endothelial barrier were rate-limiting to insulin delivery, increasing endothelial permeability would accelerate insulin action. The kinetics of myocardial insulin action were determined in the presence or absence of agents that increased endothelial permeability. Permeability was measured using Evans Blue, which binds with high affinity to albumin. During our experiments, the myocardium remained sensitive to insulin and the vasculature retained barrier integrity. Perfusion with insulin induced Akt phosphorylation in myocytes but not in the endothelium. Infusion of platelet-activating factor or vascular endothelial growth factor significantly increased permeability to albumin without altering insulin action. Amiloride, an inhibitor of fluid-phase uptake, also did not alter insulin action. These data suggest that the endothelial barrier is not rate limiting to insulin's action in the heart; its passage out of the coronary circulation is consistent with diffusion or convection. Modulation of transendothelial transport to overcome insulin resistance is unlikely to be a viable therapeutic strategy.
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Affiliation(s)
- Rajiv Sanwal
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Negar Khosraviani
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Suzanne L Advani
- Keenan Research Centre for Biomedical Science, St. Michael’s Hospital, Unity Health Toronto, Toronto, Ontario, Canada
| | - Andrew Advani
- Keenan Research Centre for Biomedical Science, St. Michael’s Hospital, Unity Health Toronto, Toronto, Ontario, Canada
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Warren L Lee
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
- Keenan Research Centre for Biomedical Science, St. Michael’s Hospital, Unity Health Toronto, Toronto, Ontario, Canada
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
- Department of Biochemistry and the Interdepartmental Division of Critical Care, University of Toronto, Toronto, Ontario, Canada
- Correspondence: Warren L. Lee, MD, PhD, St. Michael’s Hospital, 30 Bond Street, Toronto, Ontario M5B 1W8, Canada. E-mail:
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14
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Williams IM, McClatchey PM, Bracy DP, Bonner JS, Valenzuela FA, Wasserman DH. Transendothelial Insulin Transport is Impaired in Skeletal Muscle Capillaries of Obese Male Mice. Obesity (Silver Spring) 2020; 28:303-314. [PMID: 31903723 PMCID: PMC6980999 DOI: 10.1002/oby.22683] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 09/27/2019] [Indexed: 12/19/2022]
Abstract
OBJECTIVE The continuous endothelium of skeletal muscle (SkM) capillaries regulates insulin's access to skeletal myocytes. Whether impaired transendothelial insulin transport (EIT) contributes to SkM insulin resistance (IR), however, is unknown. METHODS Male and female C57/Bl6 mice were fed either chow or a high-fat diet for 16 weeks. Intravital microscopy was used to measure EIT in SkM capillaries, electron microscopy to assess endothelial ultrastructure, and glucose tracers to measure indices of glucose metabolism. RESULTS Diet-induced obesity (DIO) male mice were found to have a ~15% reduction in EIT compared with lean mice. Impaired EIT was associated with a 45% reduction in endothelial vesicles. Despite impaired EIT, hyperinsulinemia sustained delivery of insulin to the interstitial space in DIO male mice. Even with sustained interstitial insulin delivery, DIO male mice still showed SkM IR indicating severe myocellular IR in this model. Interestingly, there was no difference in EIT, endothelial ultrastructure, or SkM insulin sensitivity between lean female mice and female mice fed a high-fat diet. CONCLUSIONS These results suggest that, in male mice, obesity results in ultrastructural alterations to the capillary endothelium that delay EIT. Nonetheless, the myocyte appears to exceed the endothelium as a contributor to SkM IR in DIO male mice.
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Affiliation(s)
- Ian M Williams
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - P Mason McClatchey
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Deanna P Bracy
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
- Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, Tennessee, USA
| | | | | | - David H Wasserman
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
- Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, Tennessee, USA
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15
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Budi EH, Hoffman S, Gao S, Zhang YE, Derynck R. Integration of TGF-β-induced Smad signaling in the insulin-induced transcriptional response in endothelial cells. Sci Rep 2019; 9:16992. [PMID: 31740700 PMCID: PMC6861289 DOI: 10.1038/s41598-019-53490-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 10/22/2019] [Indexed: 01/09/2023] Open
Abstract
Insulin signaling governs many processes including glucose homeostasis and metabolism, and is therapeutically used to treat hyperglycemia in diabetes. We demonstrated that insulin-induced Akt activation enhances the sensitivity to TGF-β by directing an increase in cell surface TGF-β receptors from a pool of intracellular TGF-β receptors. Consequently, increased autocrine TGF-β signaling in response to insulin participates in insulin-induced angiogenic responses of endothelial cells. With TGF-β signaling controlling many cell responses, including differentiation and extracellular matrix deposition, and pathologically promoting fibrosis and cancer cell dissemination, we addressed to which extent autocrine TGF-β signaling participates in insulin-induced gene responses of human endothelial cells. Transcriptome analyses of the insulin response, in the absence or presence of a TGF-β receptor kinase inhibitor, revealed substantial positive and negative contributions of autocrine TGF-β signaling in insulin-responsive gene responses. Furthermore, insulin-induced responses of many genes depended on or resulted from autocrine TGF-β signaling. Our analyses also highlight extensive contributions of autocrine TGF-β signaling to basal gene expression in the absence of insulin, and identified many novel TGF-β-responsive genes. This data resource may aid in the appreciation of the roles of autocrine TGF-β signaling in normal physiological responses to insulin, and implications of therapeutic insulin usage.
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Affiliation(s)
- Erine H Budi
- Departments of Cell and Tissue Biology, and Anatomy, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California at San Francisco, San Francisco, CA, 94143-0669, USA
| | - Steven Hoffman
- Departments of Cell and Tissue Biology, and Anatomy, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California at San Francisco, San Francisco, CA, 94143-0669, USA
| | - Shaojian Gao
- Thoracic and Gastrointestinal Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, 20892-1906, USA
| | - Ying E Zhang
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, 20892-4256, USA
| | - Rik Derynck
- Departments of Cell and Tissue Biology, and Anatomy, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California at San Francisco, San Francisco, CA, 94143-0669, USA.
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16
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Jiang X, Tian W, Nicolls MR, Rockson SG. The Lymphatic System in Obesity, Insulin Resistance, and Cardiovascular Diseases. Front Physiol 2019; 10:1402. [PMID: 31798464 PMCID: PMC6868002 DOI: 10.3389/fphys.2019.01402] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 10/31/2019] [Indexed: 12/22/2022] Open
Abstract
Obesity, insulin resistance, dyslipidemia, and hypertension are fundamental clinical manifestations of the metabolic syndrome. Studies over the last few decades have implicated chronic inflammation and microvascular remodeling in the development of obesity and insulin resistance. Newer observations, however, suggest that dysregulation of the lymphatic system underlies the development of the metabolic syndrome. This review summarizes recent advances in the field, discussing how lymphatic abnormality promotes obesity and insulin resistance, and, conversely, how the metabolic syndrome impairs lymphatic function. We also discuss lymphatic biology in metabolically dysregulated diseases, including type 2 diabetes, atherosclerosis, and myocardial infarction.
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Affiliation(s)
- Xinguo Jiang
- VA Palo Alto Health Care System, Palo Alto, CA, United States.,Department of Medicine, Stanford University School of Medicine, Stanford, CA, United States
| | - Wen Tian
- VA Palo Alto Health Care System, Palo Alto, CA, United States.,Department of Medicine, Stanford University School of Medicine, Stanford, CA, United States
| | - Mark R Nicolls
- VA Palo Alto Health Care System, Palo Alto, CA, United States.,Department of Medicine, Stanford University School of Medicine, Stanford, CA, United States
| | - Stanley G Rockson
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, United States
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17
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Frendo-Cumbo S, Jaldin-Fincati JR, Coyaud E, Laurent EMN, Townsend LK, Tan JMJ, Xavier RJ, Pillon NJ, Raught B, Wright DC, Brumell JH, Klip A. Deficiency of the autophagy gene ATG16L1 induces insulin resistance through KLHL9/KLHL13/CUL3-mediated IRS1 degradation. J Biol Chem 2019; 294:16172-16185. [PMID: 31515271 DOI: 10.1074/jbc.ra119.009110] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 08/29/2019] [Indexed: 12/23/2022] Open
Abstract
Connections between deficient autophagy and insulin resistance have emerged, however, the mechanism through which reduced autophagy impairs insulin-signaling remains unknown. We examined mouse embryonic fibroblasts lacking Atg16l1 (ATG16L1 KO mouse embryonic fibroblasts (MEFs)), an essential autophagy gene, and observed deficient insulin and insulin-like growth factor-1 signaling. ATG16L1 KO MEFs displayed reduced protein content of insulin receptor substrate-1 (IRS1), pivotal to insulin signaling, whereas IRS1myc overexpression recovered downstream insulin signaling. Endogenous IRS1 protein content and insulin signaling were restored in ATG16L1 KO mouse embryonic fibroblasts (MEF) upon proteasome inhibition. Through proximity-dependent biotin identification (BioID) and co-immunoprecipitation, we found that Kelch-like proteins KLHL9 and KLHL13, which together form an E3 ubiquitin (Ub) ligase complex with cullin 3 (CUL3), are novel IRS1 interactors. Expression of Klhl9 and Klhl13 was elevated in ATG16L1 KO MEFs and siRNA-mediated knockdown of Klhl9, Klhl13, or Cul3 recovered IRS1 expression. Moreover, Klhl13 and Cul3 knockdown increased insulin signaling. Notably, adipose tissue of high-fat fed mice displayed lower Atg16l1 mRNA expression and IRS1 protein content, and adipose tissue KLHL13 and CUL3 expression positively correlated to body mass index in humans. We propose that ATG16L1 deficiency evokes insulin resistance through induction of Klhl9 and Klhl13, which, in complex with Cul3, promote proteasomal IRS1 degradation.
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Affiliation(s)
- Scott Frendo-Cumbo
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | | | - Etienne Coyaud
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario M5G 2C1, Canada
| | - Estelle M N Laurent
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario M5G 2C1, Canada
| | - Logan K Townsend
- Department of Human Health & Nutritional Sciences, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Joel M J Tan
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Ramnik J Xavier
- Gastrointestinal Unit and Center for the Study of Inflammatory Bowel Disease, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114
| | - Nicolas J Pillon
- Departments of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden 171 77
| | - Brian Raught
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario M5G 2C1, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 1L7, Canada
| | - David C Wright
- Department of Human Health & Nutritional Sciences, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - John Hunter Brumell
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada .,Department of Institute of Medical Science, University of Toronto, Toronto, Ontario M5S 1A8, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada.,SickKids IBD Centre, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
| | - Amira Klip
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada .,Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada.,Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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18
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Yazdani S, Jaldin‐Fincati JR, Pereira RVS, Klip A. Endothelial cell barriers: Transport of molecules between blood and tissues. Traffic 2019; 20:390-403. [DOI: 10.1111/tra.12645] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 04/02/2019] [Accepted: 04/02/2019] [Indexed: 12/25/2022]
Affiliation(s)
- Samaneh Yazdani
- Cell Biology ProgramThe Hospital for Sick Children Toronto Ontario Canada
| | | | | | - Amira Klip
- Cell Biology ProgramThe Hospital for Sick Children Toronto Ontario Canada
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19
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Williams IM, McClatchey PM, Bracy DP, Valenzuela FA, Wasserman DH. Acute Nitric Oxide Synthase Inhibition Accelerates Transendothelial Insulin Efflux In Vivo. Diabetes 2018; 67:1962-1975. [PMID: 30002132 PMCID: PMC6152344 DOI: 10.2337/db18-0288] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 07/03/2018] [Indexed: 12/22/2022]
Abstract
Before insulin can stimulate glucose uptake in muscle, it must be delivered to skeletal muscle (SkM) through the microvasculature. Insulin delivery is determined by SkM perfusion and the rate of movement of insulin across the capillary endothelium. The endothelium therefore plays a central role in regulating insulin access to SkM. Nitric oxide (NO) is a key regulator of endothelial function and stimulates arterial vasodilation, which increases SkM perfusion and the capillary surface area available for insulin exchange. The effects of NO on transendothelial insulin efflux (TIE), however, are unknown. We hypothesized that acute reduction of endothelial NO would reduce TIE. However, intravital imaging of TIE in mice revealed that reduction of NO by l-NG-nitro-l-arginine methyl ester (l-NAME) enhanced the rate of TIE by ∼30% and increased total extravascular insulin delivery. This accelerated TIE was associated with more rapid insulin-stimulated glucose lowering. Sodium nitroprusside, an NO donor, had no effect on TIE in mice. The effects of l-NAME on TIE were not due to changes in blood pressure alone, as a direct-acting vasoconstrictor (phenylephrine) did not affect TIE. These results demonstrate that acute NO synthase inhibition increases the permeability of capillaries to insulin, leading to an increase in delivery of insulin to SkM.
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Affiliation(s)
- Ian M Williams
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - P Mason McClatchey
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Deanna P Bracy
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
- Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, TN
| | | | - David H Wasserman
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
- Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, TN
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20
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Tokarz VL, MacDonald PE, Klip A. The cell biology of systemic insulin function. J Cell Biol 2018; 217:2273-2289. [PMID: 29622564 PMCID: PMC6028526 DOI: 10.1083/jcb.201802095] [Citation(s) in RCA: 230] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 03/21/2018] [Accepted: 03/23/2018] [Indexed: 12/12/2022] Open
Abstract
Tokarz et al. review the cell biology of insulin physiology throughout the body, from synthesis to the delivery, action, and final degradation of insulin. Insulin is the paramount anabolic hormone, promoting carbon energy deposition in the body. Its synthesis, quality control, delivery, and action are exquisitely regulated by highly orchestrated intracellular mechanisms in different organs or “stations” of its bodily journey. In this Beyond the Cell review, we focus on these five stages of the journey of insulin through the body and the captivating cell biology that underlies the interaction of insulin with each organ. We first analyze insulin’s biosynthesis in and export from the β-cells of the pancreas. Next, we focus on its first pass and partial clearance in the liver with its temporality and periodicity linked to secretion. Continuing the journey, we briefly describe insulin’s action on the blood vasculature and its still-debated mechanisms of exit from the capillary beds. Once in the parenchymal interstitium of muscle and adipose tissue, insulin promotes glucose uptake into myofibers and adipocytes, and we elaborate on the intricate signaling and vesicle traffic mechanisms that underlie this fundamental function. Finally, we touch upon the renal degradation of insulin to end its action. Cellular discernment of insulin’s availability and action should prove critical to understanding its pivotal physiological functions and how their failure leads to diabetes.
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Affiliation(s)
- Victoria L Tokarz
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Patrick E MacDonald
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | - Amira Klip
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada .,Department of Physiology, University of Toronto, Toronto, Ontario, Canada.,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
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