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Lee WL, Klip A. Endothelial Transcytosis of Insulin: Does It Contribute to Insulin Resistance? Physiology (Bethesda) 2017; 31:336-45. [PMID: 27511460 DOI: 10.1152/physiol.00010.2016] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Most research on insulin resistance has focused on impaired signaling at the level of target tissues like skeletal muscle. Insulin delivery is also important and includes recruitment and perfusion of capillaries bearing insulin, but also the transit of insulin across the capillary endothelium. The mechanisms of this second stage (insulin transcytosis) and whether it contributes to insulin resistance remain uncertain.
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Affiliation(s)
- Warren L Lee
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Canada; Department of Medicine, University of Toronto, Toronto, Canada; Department of Biochemistry, University of Toronto, Toronto, Canada; Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada; and
| | - Amira Klip
- Cell Biology Program, The Hospital for Sick Children, Toronto, Canada; Department of Biochemistry, University of Toronto, Toronto, Canada; Paediatrics, and Physiology, University of Toronto, Toronto, Canada
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52
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Khapchaev AY, Shirinsky VP. Myosin Light Chain Kinase MYLK1: Anatomy, Interactions, Functions, and Regulation. BIOCHEMISTRY (MOSCOW) 2017; 81:1676-1697. [PMID: 28260490 DOI: 10.1134/s000629791613006x] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
This review discusses and summarizes the results of molecular and cellular investigations of myosin light chain kinase (MLCK, MYLK1), the key regulator of cell motility. The structure and regulation of a complex mylk1 gene and the domain organization of its products is presented. The interactions of the mylk1 gene protein products with other proteins and posttranslational modifications of the mylk1 gene protein products are reviewed, which altogether might determine the role and place of MLCK in physiological and pathological reactions of cells and entire organisms. Translational potential of MLCK as a drug target is evaluated.
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Affiliation(s)
- A Y Khapchaev
- Russian Cardiology Research and Production Center, Moscow, 121552, Russia.
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53
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da Luz CM, Boyles MSP, Falagan-Lotsch P, Pereira MR, Tutumi HR, de Oliveira Santos E, Martins NB, Himly M, Sommer A, Foissner I, Duschl A, Granjeiro JM, Leite PEC. Poly-lactic acid nanoparticles (PLA-NP) promote physiological modifications in lung epithelial cells and are internalized by clathrin-coated pits and lipid rafts. J Nanobiotechnology 2017; 15:11. [PMID: 28143572 PMCID: PMC5282631 DOI: 10.1186/s12951-016-0238-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 12/03/2016] [Indexed: 02/07/2023] Open
Abstract
Background Poly-lactic acid nanoparticles (PLA-NP) are a type of polymeric NP, frequently used as nanomedicines, which have advantages over metallic NP such as the ability to maintain therapeutic drug levels for sustained periods of time. Despite PLA-NP being considered biocompatible, data concerning alterations in cellular physiology are scarce. Methods We conducted an extensive evaluation of PLA-NP biocompatibility in human lung epithelial A549 cells using high throughput screening and more complex methodologies. These included measurements of cytotoxicity, cell viability, immunomodulatory potential, and effects upon the cells’ proteome. We used non- and green-fluorescent PLA-NP with 63 and 66 nm diameters, respectively. Cells were exposed with concentrations of 2, 20, 100 and 200 µg/mL, for 24, 48 and 72 h, in most experiments. Moreover, possible endocytic mechanisms of internalization of PLA-NP were investigated, such as those involving caveolae, lipid rafts, macropinocytosis and clathrin-coated pits. Results Cell viability and proliferation were not altered in response to PLA-NP. Multiplex analysis of secreted mediators revealed a low-level reduction of IL-12p70 and vascular epidermal growth factor (VEGF) in response to PLA-NP, while all other mediators assessed were unaffected. However, changes to the cells’ proteome were observed in response to PLA-NP, and, additionally, the cellular stress marker miR155 was found to reduce. In dual exposures of staurosporine (STS) with PLA-NP, PLA-NP enhanced susceptibility to STS-induced cell death. Finally, PLA-NP were rapidly internalized in association with clathrin-coated pits, and, to a lesser extent, with lipid rafts. Conclusions These data demonstrate that PLA-NP are internalized and, in general, tolerated by A549 cells, with no cytotoxicity and no secretion of pro-inflammatory mediators. However, PLA-NP exposure may induce modification of biological functions of A549 cells, which should be considered when designing drug delivery systems. Moreover, the pathways of PLA-NP internalization we detected could contribute to the improvement of selective uptake strategies. Electronic supplementary material The online version of this article (doi:10.1186/s12951-016-0238-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Camila Macedo da Luz
- Laboratory of Bioengineering and in Vitro Toxicology, Directory of Metrology Applied to Life Sciences (Dimav), National Institute of Metrology Quality and Technology (INMETRO), Duque De Caxias, RJ, Brazil
| | - Matthew Samuel Powys Boyles
- Department of Molecular Biology, University of Salzburg, Salzburg, Austria.,Heriot-Watt University, Edinburg, UK
| | - Priscila Falagan-Lotsch
- Laboratory of Bioengineering and in Vitro Toxicology, Directory of Metrology Applied to Life Sciences (Dimav), National Institute of Metrology Quality and Technology (INMETRO), Duque De Caxias, RJ, Brazil
| | - Mariana Rodrigues Pereira
- Laboratory of Chemical Signaling in Nervous System, Biology Institute, Fluminense Federal University, Niteroi, RJ, Brazil
| | - Henrique Rudolf Tutumi
- Laboratory of Bioengineering and in Vitro Toxicology, Directory of Metrology Applied to Life Sciences (Dimav), National Institute of Metrology Quality and Technology (INMETRO), Duque De Caxias, RJ, Brazil
| | - Eidy de Oliveira Santos
- Laboratory of Bioengineering and in Vitro Toxicology, Directory of Metrology Applied to Life Sciences (Dimav), National Institute of Metrology Quality and Technology (INMETRO), Duque De Caxias, RJ, Brazil.,Laboratory of Biochemistry, State University Center of West Zone (UEZO), Rio de Janeiro, RJ, Brazil
| | - Nathalia Balthazar Martins
- Laboratory of Bioengineering and in Vitro Toxicology, Directory of Metrology Applied to Life Sciences (Dimav), National Institute of Metrology Quality and Technology (INMETRO), Duque De Caxias, RJ, Brazil
| | - Martin Himly
- Department of Molecular Biology, University of Salzburg, Salzburg, Austria
| | - Aniela Sommer
- Department of Cell Biology, University of Salzburg, Salzburg, Austria
| | - Ilse Foissner
- Department of Cell Biology, University of Salzburg, Salzburg, Austria
| | - Albert Duschl
- Department of Molecular Biology, University of Salzburg, Salzburg, Austria
| | - José Mauro Granjeiro
- Laboratory of Bioengineering and in Vitro Toxicology, Directory of Metrology Applied to Life Sciences (Dimav), National Institute of Metrology Quality and Technology (INMETRO), Duque De Caxias, RJ, Brazil.,Dental School, Fluminense Federal University, Niteroi, RJ, Brazil
| | - Paulo Emílio Corrêa Leite
- Laboratory of Bioengineering and in Vitro Toxicology, Directory of Metrology Applied to Life Sciences (Dimav), National Institute of Metrology Quality and Technology (INMETRO), Duque De Caxias, RJ, Brazil. .,, Av. Nossa Senhora das Gracas 50, LABET - Dimav, Predio 27, Duque de Caxias, Xerem, Rio de Janeiro, 25250-020, Brazil.
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54
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Yin C, Kim Y, Argintaru D, Heit B. Rab17 mediates differential antigen sorting following efferocytosis and phagocytosis. Cell Death Dis 2016; 7:e2529. [PMID: 28005073 PMCID: PMC5261003 DOI: 10.1038/cddis.2016.431] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 11/17/2016] [Accepted: 11/18/2016] [Indexed: 12/29/2022]
Abstract
Macrophages engulf and destroy pathogens (phagocytosis) and apoptotic cells (efferocytosis), and can subsequently initiate adaptive immune responses by presenting antigens derived from engulfed materials. Both phagocytosis and efferocytosis share a common degradative pathway in which the target is engulfed into a membrane-bound vesicle, respectively, termed the phagosome and efferosome, where they are degraded by sequential fusion with endosomes and lysosomes. Despite this shared maturation pathway, macrophages are immunogenic following phagocytosis but not efferocytosis, indicating that differential processing or trafficking of antigens must occur. Mass spectrometry and immunofluorescence microscopy of efferosomes and phagosomes in macrophages demonstrated that efferosomes lacked the proteins required for antigen presentation and instead recruited the recycling regulator Rab17. As a result, degraded materials from efferosomes bypassed the MHC class II loading compartment via the recycling endosome - a process not observed in phagosomes. Combined, these results indicate that macrophages prevent presentation of apoptotic cell-derived antigens by preferentially trafficking efferocytosed, but not phagocytosed, materials away from the MHC class II loading compartment via the recycling endosome pathway.
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Affiliation(s)
- Charles Yin
- Department of Microbiology and Immunology and The Centre for Human Immunology, The University of Western Ontario, Schulich School of Medicine and Dentistry, London, ON, Canada N6A 5C1
| | - Yohan Kim
- Department of Microbiology and Immunology and The Centre for Human Immunology, The University of Western Ontario, Schulich School of Medicine and Dentistry, London, ON, Canada N6A 5C1
| | - Dean Argintaru
- Department of Microbiology and Immunology and The Centre for Human Immunology, The University of Western Ontario, Schulich School of Medicine and Dentistry, London, ON, Canada N6A 5C1
| | - Bryan Heit
- Department of Microbiology and Immunology and The Centre for Human Immunology, The University of Western Ontario, Schulich School of Medicine and Dentistry, London, ON, Canada N6A 5C1
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55
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Kraehling JR, Chidlow JH, Rajagopal C, Sugiyama MG, Fowler JW, Lee MY, Zhang X, Ramírez CM, Park EJ, Tao B, Chen K, Kuruvilla L, Larriveé B, Folta-Stogniew E, Ola R, Rotllan N, Zhou W, Nagle MW, Herz J, Williams KJ, Eichmann A, Lee WL, Fernández-Hernando C, Sessa WC. Genome-wide RNAi screen reveals ALK1 mediates LDL uptake and transcytosis in endothelial cells. Nat Commun 2016; 7:13516. [PMID: 27869117 PMCID: PMC5121336 DOI: 10.1038/ncomms13516] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 10/11/2016] [Indexed: 12/31/2022] Open
Abstract
In humans and animals lacking functional LDL receptor (LDLR), LDL from plasma still readily traverses the endothelium. To identify the pathways of LDL uptake, a genome-wide RNAi screen was performed in endothelial cells and cross-referenced with GWAS-data sets. Here we show that the activin-like kinase 1 (ALK1) mediates LDL uptake into endothelial cells. ALK1 binds LDL with lower affinity than LDLR and saturates only at hypercholesterolemic concentrations. ALK1 mediates uptake of LDL into endothelial cells via an unusual endocytic pathway that diverts the ligand from lysosomal degradation and promotes LDL transcytosis. The endothelium-specific genetic ablation of Alk1 in Ldlr-KO animals leads to less LDL uptake into the aortic endothelium, showing its physiological role in endothelial lipoprotein metabolism. In summary, identification of pathways mediating LDLR-independent uptake of LDL may provide unique opportunities to block the initiation of LDL accumulation in the vessel wall or augment hepatic LDLR-dependent clearance of LDL. Atherosclerosis is caused by low-density lipoprotein (LDL) buildup in the vessel wall, a process thought to be mediated by LDL receptor alone. Here, the authors show that the endothelium can uptake LDL via ALK1, a TGFβ signalling receptor, suggesting new therapies for blocking LDL accumulation in the vessel wall.
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Affiliation(s)
- Jan R Kraehling
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520, USA.,Vascular Biology and Therapeutics Program (VBT), Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - John H Chidlow
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520, USA.,Vascular Biology and Therapeutics Program (VBT), Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - Chitra Rajagopal
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520, USA.,Vascular Biology and Therapeutics Program (VBT), Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - Michael G Sugiyama
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario, Canada M5B 1W8.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Joseph W Fowler
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520, USA.,Vascular Biology and Therapeutics Program (VBT), Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - Monica Y Lee
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520, USA.,Vascular Biology and Therapeutics Program (VBT), Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - Xinbo Zhang
- Vascular Biology and Therapeutics Program (VBT), Yale University School of Medicine, New Haven, Connecticut 06520, USA.,Department of Comparative Medicine, Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - Cristina M Ramírez
- Vascular Biology and Therapeutics Program (VBT), Yale University School of Medicine, New Haven, Connecticut 06520, USA.,Department of Comparative Medicine, Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - Eon Joo Park
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520, USA.,Vascular Biology and Therapeutics Program (VBT), Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - Bo Tao
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520, USA.,Vascular Biology and Therapeutics Program (VBT), Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - Keyang Chen
- Division of Endocrinology, Department of Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA
| | - Leena Kuruvilla
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - Bruno Larriveé
- Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06511, USA
| | - Ewa Folta-Stogniew
- W.M. Keck Biotechnology Resource Laboratory, Yale University School of Medicine, New Haven, Connecticut 06511, USA
| | - Roxana Ola
- Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06511, USA
| | - Noemi Rotllan
- Vascular Biology and Therapeutics Program (VBT), Yale University School of Medicine, New Haven, Connecticut 06520, USA.,Department of Comparative Medicine, Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - Wenping Zhou
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520, USA.,Vascular Biology and Therapeutics Program (VBT), Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - Michael W Nagle
- Human Genetics &Computational Biomedicine, Pfizer Worldwide Research and Development, Cambridge, Massachusetts 02139, USA
| | - Joachim Herz
- Departments of Molecular Genetics, Neuroscience, Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Kevin Jon Williams
- Division of Endocrinology, Department of Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA.,Department of Molecular and Clinical Medicine, Sahlgrenska Academy of the University of Gothenburg, Göteborg 41345, Sweden
| | - Anne Eichmann
- Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06511, USA
| | - Warren L Lee
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario, Canada M5B 1W8.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada M5S 1A8.,Departments of Biochemistry and Medicine, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Carlos Fernández-Hernando
- Vascular Biology and Therapeutics Program (VBT), Yale University School of Medicine, New Haven, Connecticut 06520, USA.,Department of Comparative Medicine, Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - William C Sessa
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520, USA.,Vascular Biology and Therapeutics Program (VBT), Yale University School of Medicine, New Haven, Connecticut 06520, USA
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56
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Abstract
Insulin resistance is a systemic disorder that affects many organs and insulin-regulated pathways. The disorder is characterized by a reduced action of insulin despite increased insulin concentrations (hyperinsulinaemia). The effects of insulin on the kidney and vasculature differ in part from the effects on classical insulin target organs. Insulin causes vasodilation by enhancing endothelial nitric oxide production through activation of the phosphatidylinositol 3-kinase pathway. In insulin-resistant states, this pathway is impaired and the mitogen-activated protein kinase pathway stimulates vasoconstriction. The action of insulin on perivascular fat tissue and the subsequent effects on the vascular wall are not fully understood, but the hepatokine fetuin-A, which is released by fatty liver, might promote the proinflammatory effects of perivascular fat. The strong association of salt-sensitive arterial hypertension with insulin resistance indicates an involvement of the kidney in the insulin resistance syndrome. The insulin receptor is expressed on renal tubular cells and podocytes and insulin signalling has important roles in podocyte viability and tubular function. Renal sodium transport is preserved in insulin resistance and contributes to the salt-sensitivity of blood pressure in hyperinsulinaemia. Therapeutically, renal and vascular insulin resistance can be improved by an integrated holistic approach aimed at restoring overall insulin sensitivity and improving insulin signalling.
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57
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Owen A, Rannard S. Strengths, weaknesses, opportunities and challenges for long acting injectable therapies: Insights for applications in HIV therapy. Adv Drug Deliv Rev 2016; 103:144-156. [PMID: 26916628 PMCID: PMC4935562 DOI: 10.1016/j.addr.2016.02.003] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Revised: 02/10/2016] [Accepted: 02/12/2016] [Indexed: 12/11/2022]
Abstract
Advances in solid drug nanoparticle technologies have resulted in a number of long-acting (LA) formulations with the potential for once monthly or longer administration. Such formulations offer great utility for chronic diseases, particularly when a lack of medication compliance may be detrimental to treatment response. Two such formulations are in clinical development for HIV but the concept of LA delivery has its origins in indications such as schizophrenia and contraception. Many terms have been utilised to describe the LA approach and standardisation would be beneficial. Ultimately, definitions will depend upon specific indications and routes of delivery, but for HIV we propose benchmarks that reflect perceived clinical benefits and available data on patient attitudes. Specifically, we propose dosing intervals of ≥1week, ≥1month or ≥6months, for oral, injectable or implantable strategies, respectively. This review focuses upon the critical importance of potency in achieving the LA outcome for injectable formulations and explores established and emerging technologies that have been employed across indications. Key technological challenges such as the need for consistency and ease of administration for drug combinations, are also discussed. Finally, the review explores the gaps in knowledge regarding the pharmacology of drug release from particulate-based LA injectable suspensions. A number of hypotheses are discussed based upon available data relating to local drug metabolism, active transport systems, the lymphatics, macrophages and patient-specific factors. Greater knowledge of the mechanisms that underpin drug release and protracted exposure will help facilitate further development of this strategy to achieve the promising clinical benefits.
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Affiliation(s)
- Andrew Owen
- Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, 70 Pembroke Place, University of Liverpool, Liverpool L693GF, UK
| | - Steve Rannard
- Department of Chemistry, Crown Street, University of Liverpool, L69 3BX, UK
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58
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Fullstone G, Nyberg S, Tian X, Battaglia G. From the Blood to the Central Nervous System: A Nanoparticle's Journey Through the Blood-Brain Barrier by Transcytosis. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2016; 130:41-72. [PMID: 27678174 DOI: 10.1016/bs.irn.2016.06.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Designing nanoparticles that effectively enter the central nervous system (CNS) rapidly and without alteration is one of the major challenges in the use of nanotechnology for the brain. In this chapter, we explore the process of transcytosis, a receptor-mediated transport pathway that permits endogenous macromolecules to enter the CNS by crossing the blood-brain barrier. Transcytosis across the blood-brain barrier involves a number of distinct stages, including receptor binding, endocytosis into a transport vesicle, trafficking of the vesicle to the opposite side of the cell, and finally exocytosis and release of cargo. For each stage, we discuss the current knowledge on biological, physiological, and physical factors that influence nanoparticle transit through that stage of transcytosis, with implications for nanoparticle design. Finally, we look at the current progress in designing nanoparticles that exploit transcytosis for CNS delivery.
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Affiliation(s)
- G Fullstone
- University College London, London, United Kingdom.
| | - S Nyberg
- University College London, London, United Kingdom; Biological Sciences, Sunnybrook Research Institute, Toronto, ON, Canada.
| | - X Tian
- School of Life Sciences, Anhui University, Hefei, People's Republic of China
| | - G Battaglia
- University College London, London, United Kingdom.
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59
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Mahmoud AM, Brown MD, Phillips SA, Haus JM. Skeletal Muscle Vascular Function: A Counterbalance of Insulin Action. Microcirculation 2016; 22:327-47. [PMID: 25904196 DOI: 10.1111/micc.12205] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 04/20/2015] [Indexed: 12/11/2022]
Abstract
Insulin is a vasoactive hormone that regulates vascular homeostasis by maintaining balance of endothelial-derived NO and ET-1. Although there is general agreement that insulin resistance and the associated hyperinsulinemia disturb this balance, the vascular consequences for hyperinsulinemia in isolation from insulin resistance are still unclear. Presently, there is no simple answer for this question, especially in a background of mixed reports examining the effects of experimental hyperinsulinemia on endothelial-mediated vasodilation. Understanding the mechanisms by which hyperinsulinemia induces vascular dysfunction is essential in advancing treatment and prevention of insulin resistance-related vascular complications. Thus, we review literature addressing the effects of hyperinsulinemia on vascular function. Furthermore, we give special attention to the vasoregulatory effects of hyperinsulinemia on skeletal muscle, the largest insulin-dependent organ in the body. This review also characterizes the differential vascular effects of hyperinsulinemia on large conduit vessels versus small resistance microvessels and the effects of metabolic variables in an effort to unravel potential sources of discrepancies in the literature. At the cellular level, we provide an overview of insulin signaling events governing vascular tone. Finally, we hypothesize a role for hyperinsulinemia and insulin resistance in the development of CVD.
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Affiliation(s)
- Abeer M Mahmoud
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA.,Integrative Physiology Laboratory, College of Applied Health Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Michael D Brown
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA.,Integrative Physiology Laboratory, College of Applied Health Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Shane A Phillips
- Integrative Physiology Laboratory, College of Applied Health Sciences, University of Illinois at Chicago, Chicago, Illinois, USA.,Department of Physical Therapy, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Jacob M Haus
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA.,Integrative Physiology Laboratory, College of Applied Health Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
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60
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Batchu SN, Majumder S, Bowskill BB, White KE, Advani SL, Brijmohan AS, Liu Y, Thai K, Azizi PM, Lee WL, Advani A. Prostaglandin I2 Receptor Agonism Preserves β-Cell Function and Attenuates Albuminuria Through Nephrin-Dependent Mechanisms. Diabetes 2016; 65:1398-409. [PMID: 26868296 DOI: 10.2337/db15-0783] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 02/01/2016] [Indexed: 11/13/2022]
Abstract
Discovery of common pathways that mediate both pancreatic β-cell function and end-organ function offers the opportunity to develop therapies that modulate glucose homeostasis and separately slow the development of diabetes complications. Here, we investigated the in vitro and in vivo effects of pharmacological agonism of the prostaglandin I2 (IP) receptor in pancreatic β-cells and in glomerular podocytes. The IP receptor agonist MRE-269 increased intracellular 3',5'-cyclic adenosine monophosphate (cAMP), augmented glucose-stimulated insulin secretion (GSIS), and increased viability in MIN6 β-cells. Its prodrug form, selexipag, augmented GSIS and preserved islet β-cell mass in diabetic mice. Determining that this preservation of β-cell function is mediated through cAMP/protein kinase A (PKA)/nephrin-dependent pathways, we found that PKA inhibition, nephrin knockdown, or targeted mutation of phosphorylated nephrin tyrosine residues 1176 and 1193 abrogated the actions of MRE-269 in MIN6 cells. Because nephrin is important to glomerular permselectivity, we next set out to determine whether IP receptor agonism similarly affects nephrin phosphorylation in podocytes. Expression of the IP receptor in podocytes was confirmed in cultured cells by immunoblotting and quantitative real-time PCR and in mouse kidneys by immunogold electron microscopy, and its agonism 1) increased cAMP, 2) activated PKA, 3) phosphorylated nephrin, and 4) attenuated albumin transcytosis. Finally, treatment of diabetic endothelial nitric oxide synthase knockout mice with selexipag augmented renal nephrin phosphorylation and attenuated albuminuria development independently of glucose change. Collectively, these observations describe a pharmacological strategy that posttranslationally modifies nephrin and the effects of this strategy in the pancreas and in the kidney.
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MESH Headings
- Acetamides/therapeutic use
- Acetates/pharmacology
- Animals
- Cell Line
- Cell Survival/drug effects
- Diabetes Mellitus, Experimental/complications
- Diabetes Mellitus, Experimental/drug therapy
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/pathology
- Diabetic Nephropathies/metabolism
- Diabetic Nephropathies/pathology
- Diabetic Nephropathies/physiopathology
- Diabetic Nephropathies/prevention & control
- Humans
- Hypoglycemic Agents/pharmacology
- Hypoglycemic Agents/therapeutic use
- Insulin/agonists
- Insulin/metabolism
- Insulin Secretion
- Insulin-Secreting Cells/drug effects
- Insulin-Secreting Cells/metabolism
- Membrane Proteins/antagonists & inhibitors
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Mice, Inbred C57BL
- Mice, Knockout
- Mutation
- Phosphorylation/drug effects
- Podocytes/drug effects
- Podocytes/metabolism
- Podocytes/pathology
- Podocytes/ultrastructure
- Prodrugs/therapeutic use
- Protein Processing, Post-Translational/drug effects
- Pyrazines/pharmacology
- Pyrazines/therapeutic use
- RNA Interference
- Receptors, Epoprostenol/agonists
- Receptors, Epoprostenol/genetics
- Receptors, Epoprostenol/metabolism
- Renal Insufficiency/complications
- Renal Insufficiency/metabolism
- Renal Insufficiency/pathology
- Renal Insufficiency/prevention & control
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Affiliation(s)
- Sri N Batchu
- Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada
| | - Syamantak Majumder
- Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada
| | - Bridgit B Bowskill
- Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada
| | - Kathryn E White
- Electron Microscopy Research Services, Newcastle University, Newcastle upon Tyne, U.K
| | - Suzanne L Advani
- Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada
| | - Angela S Brijmohan
- Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada
| | - Youan Liu
- Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada
| | - Kerri Thai
- Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada
| | - Paymon M Azizi
- Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada
| | - Warren L Lee
- Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada
| | - Andrew Advani
- Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada
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Zhang B, Jiang T, Ling L, Cao Z, Zhao J, Tuo Y, She X, Shen S, Jiang X, Hu Y, Pang Z. Enhanced Antitumor Activity of EGFP-EGF1-Conjugated Nanoparticles by a Multitargeting Strategy. ACS APPLIED MATERIALS & INTERFACES 2016; 8:8918-8927. [PMID: 26890991 DOI: 10.1021/acsami.6b00036] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Tumor stromal cells have been increasingly recognized to interact with tumor parenchyma cells and promote tumor growth. Therefore, we speculated that therapeutics delivery to both parenchyma cells and stromal cells simultaneously might treat a tumor more effectively. Tissue factor (TF) was shown to be extensively located in a tumor and was abundantly sited in both tumor parenchyma cells and stromal cells including neo-vascular cells, tumor-associated fibroblasts, and tumor-associated macrophages, indicating it might function as a favorable target for drug delivery to multiple cell types simultaneously. EGFP-EGF1 is a fusion protein derived from factor VII, the natural ligand of TF. It retains the specific TF binding capability but does not cause coagulation. In the present study, a nanoparticle modified with EGFP-EGF1 (ENP) was constructed as a multitargeting drug delivery system. The protein binding experiment showed EGFP-EGF1 could bind well to A549 tumor cells and other stromal cells including neo-vascular cells, tumor-associated fibroblasts, and tumor-associated macrophages. Compared with unmodified nanoparticles (NP), ENP uptake by A549 cells and those stromal cells was significantly enhanced but inhibited by excessive free EGFP-EGF1. In addition, ENP induced more A549 tumor cell apoptosis than Taxol and NP when paclitaxel (PTX) was loaded. In vivo, ENP accumulated more specially in TF-overexpressed A549 tumors by in vivo imaging, mainly regions unoccupied by factor VII and targeted tumor parenchyma cells as well as different types of stromal cells by immunofluorescence staining. Treatment with PTX-loaded ENP (ENP-PTX) significantly reduced the A549 tumor growth in nude mice while NP-PTX- and Taxol-treated mice had lower response to the therapy. Furthermore, H&E and TUNEL staining revealed that ENP-PTX induced more severe tumor necrosis and more extensive cell apoptosis. Altogether, the present study demonstrated that ENP could target multiple key cell types in tumors through TF, which could be utilized to improve the therapeutic effect of anticancer drugs.
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Affiliation(s)
- Bo Zhang
- Institute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science & Technology , Wuhan, Hubei 430022, China
| | - Ting Jiang
- Institute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science & Technology , Wuhan, Hubei 430022, China
| | - Li Ling
- School of Pharmacy, Fudan University, Key Laboratory of Smart Drug Delivery, Ministry of Education, 826 Zhangheng Road, Shanghai, 201203, China
| | - Zhonglian Cao
- Instrumental Analysis Center of School of Pharmacy, Fudan University , 826 Zhangheng Road, Shanghai, 201203, China
| | - Jingjing Zhao
- School of Pharmacy, Fudan University, Key Laboratory of Smart Drug Delivery, Ministry of Education, 826 Zhangheng Road, Shanghai, 201203, China
| | - Yanyan Tuo
- School of Pharmacy, Fudan University, Key Laboratory of Smart Drug Delivery, Ministry of Education, 826 Zhangheng Road, Shanghai, 201203, China
| | - Xiaojian She
- School of Pharmacy, Fudan University, Key Laboratory of Smart Drug Delivery, Ministry of Education, 826 Zhangheng Road, Shanghai, 201203, China
| | - Shun Shen
- School of Pharmacy, Fudan University, Key Laboratory of Smart Drug Delivery, Ministry of Education, 826 Zhangheng Road, Shanghai, 201203, China
| | - Xinguo Jiang
- School of Pharmacy, Fudan University, Key Laboratory of Smart Drug Delivery, Ministry of Education, 826 Zhangheng Road, Shanghai, 201203, China
| | - Yu Hu
- Institute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science & Technology , Wuhan, Hubei 430022, China
| | - Zhiqing Pang
- School of Pharmacy, Fudan University, Key Laboratory of Smart Drug Delivery, Ministry of Education, 826 Zhangheng Road, Shanghai, 201203, China
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Kusters YHAM, Barrett EJ. Muscle microvasculature's structural and functional specializations facilitate muscle metabolism. Am J Physiol Endocrinol Metab 2016; 310:E379-87. [PMID: 26714849 PMCID: PMC4888529 DOI: 10.1152/ajpendo.00443.2015] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 12/18/2015] [Indexed: 12/29/2022]
Abstract
We review the evolving findings from studies that examine the relationship between the structural and functional properties of skeletal muscle's vasculature and muscle metabolism. Unique aspects of the organization of the muscle microvasculature are highlighted. We discuss the role of vasomotion at the microscopic level and of flowmotion at the tissue level as modulators of perfusion distribution in muscle. We then consider in some detail how insulin and exercise each modulate muscle perfusion at both the microvascular and whole tissue level. The central role of the vascular endothelial cell in modulating both perfusion and transendothelial insulin and nutrient transport is also reviewed. The relationship between muscle metabolic insulin resistance and the vascular action of insulin in muscle continues to indicate an important role for the microvasculature as a target for insulin action and that impairing insulin's microvascular action significantly affects body glucose metabolism.
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Affiliation(s)
- Yvo H A M Kusters
- Department of Internal Medicine, Maastricht University Medical Center, Maastricht, The Netherlands; Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre, Maastricht, The Netherlands; and
| | - Eugene J Barrett
- Department of Medicine, Pediatrics, and Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia
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Kuebler WM, Wittenberg C, Lee WL, Reppien E, Goldenberg NM, Lindner K, Gao Y, Winoto-Morbach S, Drab M, Mühlfeld C, Dombrowsky H, Ochs M, Schütze S, Uhlig S. Thrombin stimulates albumin transcytosis in lung microvascular endothelial cells via activation of acid sphingomyelinase. Am J Physiol Lung Cell Mol Physiol 2016; 310:L720-32. [PMID: 26851257 DOI: 10.1152/ajplung.00157.2015] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 01/22/2016] [Indexed: 01/12/2023] Open
Abstract
Transcellular albumin transport occurs via caveolae that are abundant in lung microvascular endothelial cells. Stimulation of albumin transcytosis by proinflammatory mediators may contribute to alveolar protein leak in lung injury, yet the regulation of albumin transport and its underlying molecular mechanisms are so far incompletely understood. Here we tested the hypothesis that thrombin may stimulate transcellular albumin transport across lung microvascular endothelial cells in an acid-sphingomyelinase dependent manner. Thrombin increased the transport of fluorescently labeled albumin across confluent human lung microvascular endothelial cell (HMVEC-L) monolayers to an extent that markedly exceeds the rate of passive diffusion. Thrombin activated acid sphingomyelinase (ASM) and increased ceramide production in HMVEC-L, but not in bovine pulmonary artery cells, which showed little albumin transport in response to thrombin. Thrombin increased total caveolin-1 (cav-1) content in both whole cell lysates and lipid rafts from HMVEC-L, and this effect was blocked by inhibition of ASM or de novo protein biosynthesis. Thrombin-induced uptake of albumin into lung microvascular endothelial cells was confirmed in isolated-perfused lungs by real-time fluorescence imaging and electron microscopy of gold-labeled albumin. Inhibition of ASM attenuated thrombin-induced albumin transport both in confluent HMVEC-L and in intact lungs, whereas HMVEC-L treatment with exogenous ASM increased albumin transport and enriched lipid rafts in cav-1. Our findings indicate that thrombin stimulates transcellular albumin transport in an acid sphingomyelinase-dependent manner by inducing de novo synthesis of cav-1 and its recruitment to membrane lipid rafts.
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Affiliation(s)
- Wolfgang M Kuebler
- Institute of Physiology, Charité - Universitätsmedizin Berlin, Berlin, Germany; German Heart Institute Berlin, Berlin, Germany; The Keenan Research Centre for Biomedical Science of St. Michael's, Toronto, Ontario, Canada; Departments of Surgery and Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Claudia Wittenberg
- Institute of Physiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Warren L Lee
- The Keenan Research Centre for Biomedical Science of St. Michael's, Toronto, Ontario, Canada; Interdepartmental Division of Critical Care, Departments of Medicine and Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Eike Reppien
- Division of Pulmonary Pharmacology, Research Center Borstel, Borstel, Germany
| | - Neil M Goldenberg
- The Keenan Research Centre for Biomedical Science of St. Michael's, Toronto, Ontario, Canada
| | - Karsten Lindner
- Division of Pulmonary Pharmacology, Research Center Borstel, Borstel, Germany
| | - Yizhuo Gao
- The Keenan Research Centre for Biomedical Science of St. Michael's, Toronto, Ontario, Canada
| | | | - Marek Drab
- Institute of Immunology and Experimental Therapy, Wroclaw, Poland
| | - Christian Mühlfeld
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany; Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research (DLZ), Hannover, Germany; Cluster of Excellence REBIRTH (From Regenerative Biology to Reconstructive Therapy), Hannover, Germany; and
| | - Heike Dombrowsky
- Division of Pulmonary Pharmacology, Research Center Borstel, Borstel, Germany
| | - Matthias Ochs
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany; Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research (DLZ), Hannover, Germany; Cluster of Excellence REBIRTH (From Regenerative Biology to Reconstructive Therapy), Hannover, Germany; and
| | - Stefan Schütze
- Institute of Immunology, University of Kiel, Kiel, Germany
| | - Stefan Uhlig
- Division of Pulmonary Pharmacology, Research Center Borstel, Borstel, Germany; Institute of Pharmacology and Toxicology, RWTH Aachen, Aachen, Germany
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Yan M, Zhang Y, Qin H, Liu K, Guo M, Ge Y, Xu M, Sun Y, Zheng X. Cytotoxicity of CdTe quantum dots in human umbilical vein endothelial cells: the involvement of cellular uptake and induction of pro-apoptotic endoplasmic reticulum stress. Int J Nanomedicine 2016; 11:529-42. [PMID: 26893560 PMCID: PMC4745859 DOI: 10.2147/ijn.s93591] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Cadmium telluride quantum dots (CdTe QDs) have been proposed to induce oxidative stress, which plays a crucial role in CdTe QDs-mediated mitochondrial-dependent apoptosis in human umbilical vein endothelial cells (HUVECs). However, the direct interactions of CdTe QDs with HUVECs and their potential impairment of other organelles like endoplasmic reticulum (ER) in HUVECs are poorly understood. In this study, we reported that the negatively charged CdTe QDs (−21.63±0.91 mV), with good dispersity and fluorescence stability, were rapidly internalized via endocytosis by HUVECs, as the notable internalization could be inhibited up to 95.52% by energy depletion (NaN3/deoxyglucose or low temperature). The endocytosis inhibitors (methyl-β-cyclodextrin, genistein, sucrose, chlorpromazine, and colchicine) dramatically decreased the uptake of CdTe QDs by HUVECs, suggesting that both caveolae/raft- and clathrin-mediated endocytosis were involved in the endothelial uptake of CdTe QDs. Using immunocytochemistry, a striking overlap of the internalized CdTe QDs and ER marker was observed, which indicates that QDs may be transported to ER. The CdTe QDs also caused remarkable ER stress responses in HUVECs, confirmed by significant dilatation of ER cisternae, upregulation of ER stress markers GRP78/GRP94, and activation of protein kinase RNA-like ER kinase-eIF2α-activating transcription factor 4 pathway (including phosphorylation of both protein kinase RNA-like ER kinase and eIF2α and elevated level of activating transcription factor 4). CdTe QDs further promoted an increased C/EBP homologous protein expression, phosphorylation of c-JUN NH2-terminal kinase, and cleavage of ER-resident caspase-4, while the specific inhibitor (SP600125, Z-LEVD-fmk, or salubrinal) significantly attenuated QDs-triggered apoptosis, indicating that all three ER stress-mediated apoptosis pathways were activated and the direct participation of ER in the CdTe QDs-caused apoptotic cell death in HUVECs. Our findings provide important new insights into QDs toxicity and reveal potential cardiovascular risks for the future applications of QDs.
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Affiliation(s)
- Ming Yan
- Department of Biomedical Engineering, College of Life Information Science and Instrument Engineering, Hangzhou Dianzi University, Hangzhou, People's Republic of China
| | - Yun Zhang
- Basic Medical Sciences, College of Medicine, Shaoxing University, Shaoxing, People's Republic of China
| | - Haiyan Qin
- Department of Chemistry, Zhejiang University, Hangzhou, People's Republic of China
| | - Kezhou Liu
- Department of Biomedical Engineering, College of Life Information Science and Instrument Engineering, Hangzhou Dianzi University, Hangzhou, People's Republic of China
| | - Miao Guo
- Department of Biomedical Engineering, College of Life Information Science and Instrument Engineering, Hangzhou Dianzi University, Hangzhou, People's Republic of China
| | - Yakun Ge
- Department of Biomedical Engineering, College of Life Information Science and Instrument Engineering, Hangzhou Dianzi University, Hangzhou, People's Republic of China
| | - Mingen Xu
- Department of Biomedical Engineering, College of Life Information Science and Instrument Engineering, Hangzhou Dianzi University, Hangzhou, People's Republic of China
| | - Yonghong Sun
- Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Department of Biomedical Engineering, Zhejiang University, Hangzhou, People's Republic of China
| | - Xiaoxiang Zheng
- Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Department of Biomedical Engineering, Zhejiang University, Hangzhou, People's Republic of China
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65
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Influenza Virus Infection Induces Platelet-Endothelial Adhesion Which Contributes to Lung Injury. J Virol 2015; 90:1812-23. [PMID: 26637453 DOI: 10.1128/jvi.02599-15] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 11/25/2015] [Indexed: 01/13/2023] Open
Abstract
Lung injury after influenza infection is characterized by increased permeability of the lung microvasculature, culminating in acute respiratory failure. Platelets interact with activated endothelial cells and have been implicated in the pathogenesis of some forms of acute lung injury. Autopsy studies have revealed pulmonary microthrombi after influenza infection, and epidemiological studies suggest that influenza vaccination is protective against pulmonary thromboembolism; however, the effect of influenza infection on platelet-endothelial interactions is unclear. We demonstrate that endothelial infection with both laboratory and clinical strains of influenza virus increased the adhesion of human platelets to primary human lung microvascular endothelial cells. Platelets adhered to infected cells as well as to neighboring cells, suggesting a paracrine effect. Influenza infection caused the upregulation of von Willebrand factor and ICAM-1, but blocking these receptors did not prevent platelet-endothelial adhesion. Instead, platelet adhesion was inhibited by both RGDS peptide and a blocking antibody to platelet integrin α5β1, implicating endothelial fibronectin. Concordantly, lung histology from infected mice revealed viral dose-dependent colocalization of viral nucleoprotein and the endothelial marker PECAM-1, while platelet adhesion and fibronectin deposition also were observed in the lungs of influenza-infected mice. Inhibition of platelets using acetylsalicylic acid significantly improved survival, a finding confirmed using a second antiplatelet agent. Thus, influenza infection induces platelet-lung endothelial adhesion via fibronectin, contributing to mortality from acute lung injury. The inhibition of platelets may constitute a practical adjunctive strategy to the treatment of severe infections with influenza.IMPORTANCE There is growing appreciation of the involvement of the lung endothelium in the pathogenesis of severe infections with influenza virus. We have recently shown that the virus can infect human lung endothelial cells, but the functional consequences of this infection are unknown (S. M. Armstrong, C. Wang, J. Tigdi, X. Si, C. Dumpit, S. Charles, A. Gamage, T. J. Moraes, and W. L. Lee, PLoS One 7:e47323, 2012, http://dx.doi.org/10.1371/journal.pone.0047323). Here, we show that this infection causes platelets to adhere to the lung endothelium. Importantly, blocking platelets using two distinct antiplatelet drugs improved survival in a mouse model of severe influenza infection. Thus, platelet inhibition may constitute a novel therapeutic strategy to improve the host response to severe infections with influenza.
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66
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Haas TL, Nwadozi E. Regulation of skeletal muscle capillary growth in exercise and disease. Appl Physiol Nutr Metab 2015; 40:1221-32. [PMID: 26554747 DOI: 10.1139/apnm-2015-0336] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Capillaries, which are the smallest and most abundant type of blood vessel, form the primary site of gas, nutrient, and waste transfer between the vascular and tissue compartments. Skeletal muscle exhibits the capacity to generate new capillaries (angiogenesis) as an adaptation to exercise training, thus ensuring that the heightened metabolic demand of the active muscle is matched by an improved capacity for distribution of gases, nutrients, and waste products. This review summarizes the current understanding of the regulation of skeletal muscle capillary growth. The multi-step process of angiogenesis is coordinated through the integration of a diverse array of signals associated with hypoxic, metabolic, hemodynamic, and mechanical stresses within the active muscle. The contributions of metabolic and mechanical factors to the modulation of key pro- and anti-angiogenic molecules are discussed within the context of responses to a single aerobic exercise bout and short-term and long-term training. Finally, the paradoxical lack of angiogenesis in peripheral artery disease and diabetes and the implications for disease progression and muscle health are discussed. Future studies that emphasize an integrated analysis of the mechanisms that control skeletal muscle capillary growth will enable development of targeted exercise programs that effectively promote angiogenesis in healthy individuals and in patient populations.
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Affiliation(s)
- Tara L Haas
- Angiogenesis Research Group, York University, Toronto, ON M3J 1P3, Canada.,Angiogenesis Research Group, York University, Toronto, ON M3J 1P3, Canada
| | - Emmanuel Nwadozi
- Angiogenesis Research Group, York University, Toronto, ON M3J 1P3, Canada.,Angiogenesis Research Group, York University, Toronto, ON M3J 1P3, Canada
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67
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Armstrong SM, Sugiyama MG, Fung KYY, Gao Y, Wang C, Levy AS, Azizi P, Roufaiel M, Zhu SN, Neculai D, Yin C, Bolz SS, Seidah NG, Cybulsky MI, Heit B, Lee WL. A novel assay uncovers an unexpected role for SR-BI in LDL transcytosis. Cardiovasc Res 2015; 108:268-77. [PMID: 26334034 DOI: 10.1093/cvr/cvv218] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 08/24/2015] [Indexed: 01/16/2023] Open
Abstract
AIMS Retention of low-density lipoprotein (LDL) cholesterol beneath the arterial endothelium initiates an inflammatory response culminating in atherosclerosis. Since the overlying endothelium is healthy and intact early on, it is likely that LDL passes through endothelial cells by transcytosis. However, technical challenges have made confirming this notion and elucidating the mechanisms of transcytosis difficult. We developed a novel assay for measuring LDL transcytosis in real time across coronary endothelial cell monolayers; we used this approach to identify the receptor involved. METHODS AND RESULTS Murine aortas were perfused ex vivo with LDL and dextran of a smaller molecular radius. LDL (but not dextran) accumulated under the endothelium, indicating that LDL transcytosis occurs in intact vessels. We then confirmed that LDL transcytosis occurs in vitro using human coronary artery endothelial cells. An assay was developed to quantify transcytosis of DiI-LDL in real time using total internal reflection fluorescence microscopy. DiI-LDL transcytosis was inhibited by excess unlabelled LDL, while degradation of the LDL receptor by PCSK9 had no effect. Instead, LDL colocalized partially with the scavenger receptor SR-BI and overexpression of SR-BI increased LDL transcytosis; knockdown by siRNA significantly reduced it. Excess HDL, the canonical SR-BI ligand, significantly decreased LDL transcytosis. Aortas from SR-BI-deficient mice were perfused ex vivo with LDL and accumulated significantly less sub-endothelial LDL compared with wild-type littermates. CONCLUSION We developed an assay to quantify LDL transcytosis across endothelial cells and discovered an unexpected role for SR-BI. Elucidating the mechanisms of LDL transcytosis may identify novel targets for the prevention or therapy of atherosclerosis.
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Affiliation(s)
- Susan M Armstrong
- Keenan Research Centre, St Michael's Hospital, 30 Bond Street, Toronto, ON, Canada, M5B 1W8 Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
| | - Michael G Sugiyama
- Keenan Research Centre, St Michael's Hospital, 30 Bond Street, Toronto, ON, Canada, M5B 1W8 Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Karen Y Y Fung
- Keenan Research Centre, St Michael's Hospital, 30 Bond Street, Toronto, ON, Canada, M5B 1W8
| | - Yizhuo Gao
- Keenan Research Centre, St Michael's Hospital, 30 Bond Street, Toronto, ON, Canada, M5B 1W8
| | - Changsen Wang
- Keenan Research Centre, St Michael's Hospital, 30 Bond Street, Toronto, ON, Canada, M5B 1W8
| | - Andrew S Levy
- Keenan Research Centre, St Michael's Hospital, 30 Bond Street, Toronto, ON, Canada, M5B 1W8
| | - Paymon Azizi
- Keenan Research Centre, St Michael's Hospital, 30 Bond Street, Toronto, ON, Canada, M5B 1W8
| | - Mark Roufaiel
- Toronto General Research Institute (TGRI), Toronto, Canada
| | - Su-Ning Zhu
- Toronto General Research Institute (TGRI), Toronto, Canada
| | | | - Charles Yin
- Department of Microbiology and Immunology, The University of Western Ontario, London, ON, Canada
| | - Steffen-Sebastian Bolz
- Keenan Research Centre, St Michael's Hospital, 30 Bond Street, Toronto, ON, Canada, M5B 1W8
| | | | - Myron I Cybulsky
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada Toronto General Research Institute (TGRI), Toronto, Canada
| | - Bryan Heit
- Department of Microbiology and Immunology, The University of Western Ontario, London, ON, Canada
| | - Warren L Lee
- Keenan Research Centre, St Michael's Hospital, 30 Bond Street, Toronto, ON, Canada, M5B 1W8 Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada Interdepartmental Division of Critical Care Medicine and the Department of Medicine, University of Toronto, Toronto, ON, Canada
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68
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Pillon NJ, Azizi PM, Li YE, Liu J, Wang C, Chan KL, Hopperton KE, Bazinet RP, Heit B, Bilan PJ, Lee WL, Klip A. Palmitate-induced inflammatory pathways in human adipose microvascular endothelial cells promote monocyte adhesion and impair insulin transcytosis. Am J Physiol Endocrinol Metab 2015; 309:E35-44. [PMID: 25944880 DOI: 10.1152/ajpendo.00611.2014] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 04/25/2015] [Indexed: 02/01/2023]
Abstract
Obesity is associated with inflammation and immune cell recruitment to adipose tissue, muscle and intima of atherosclerotic blood vessels. Obesity and hyperlipidemia are also associated with tissue insulin resistance and can compromise insulin delivery to muscle. The muscle/fat microvascular endothelium mediates insulin delivery and facilitates monocyte transmigration, yet its contribution to the consequences of hyperlipidemia is poorly understood. Using primary endothelial cells from human adipose tissue microvasculature (HAMEC), we investigated the effects of physiological levels of fatty acids on endothelial inflammation and function. Expression of cytokines and adhesion molecules was measured by RT-qPCR. Signaling pathways were evaluated by pharmacological manipulation and immunoblotting. Surface expression of adhesion molecules was determined by immunohistochemistry. THP1 monocyte interaction with HAMEC was measured by cell adhesion and migration across transwells. Insulin transcytosis was measured by total internal reflection fluorescence microscopy. Palmitate, but not palmitoleate, elevated the expression of IL-6, IL-8, TLR2 (Toll-like receptor 2), and intercellular adhesion molecule 1 (ICAM-1). HAMEC had markedly low fatty acid uptake and oxidation, and CD36 inhibition did not reverse the palmitate-induced expression of adhesion molecules, suggesting that inflammation did not arise from palmitate uptake/metabolism. Instead, inhibition of TLR4 to NF-κB signaling blunted palmitate-induced ICAM-1 expression. Importantly, palmitate-induced surface expression of ICAM-1 promoted monocyte binding and transmigration. Conversely, palmitate reduced insulin transcytosis, an effect reversed by TLR4 inhibition. In summary, palmitate activates inflammatory pathways in primary microvascular endothelial cells, impairing insulin transport and increasing monocyte transmigration. This behavior may contribute in vivo to reduced tissue insulin action and enhanced tissue infiltration by immune cells.
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Affiliation(s)
- Nicolas J Pillon
- Cell Biology Program, the Hospital for Sick Children, Toronto, Ontario, Canada
| | - Paymon M Azizi
- Cell Biology Program, the Hospital for Sick Children, Toronto, Ontario, Canada; Keenan Research Centre, St. Michael's Hospital, Toronto, Ontario, Canada
| | - Yujin E Li
- Cell Biology Program, the Hospital for Sick Children, Toronto, Ontario, Canada
| | - Jun Liu
- Cell Biology Program, the Hospital for Sick Children, Toronto, Ontario, Canada
| | - Changsen Wang
- Keenan Research Centre, St. Michael's Hospital, Toronto, Ontario, Canada
| | - Kenny L Chan
- Cell Biology Program, the Hospital for Sick Children, Toronto, Ontario, Canada
| | - Kathryn E Hopperton
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Richard P Bazinet
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Bryan Heit
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada; and
| | - Philip J Bilan
- Cell Biology Program, the Hospital for Sick Children, Toronto, Ontario, Canada
| | - Warren L Lee
- Keenan Research Centre, St. Michael's Hospital, Toronto, Ontario, Canada
| | - Amira Klip
- Cell Biology Program, the Hospital for Sick Children, Toronto, Ontario, Canada;
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