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Linville RM, Sklar MB, Grifno GN, Nerenberg RF, Zhou J, Ye R, DeStefano JG, Guo Z, Jha R, Jamieson JJ, Zhao N, Searson PC. Three-dimensional microenvironment regulates gene expression, function, and tight junction dynamics of iPSC-derived blood-brain barrier microvessels. Fluids Barriers CNS 2022; 19:87. [PMID: 36333694 PMCID: PMC9636829 DOI: 10.1186/s12987-022-00377-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 10/03/2022] [Indexed: 11/08/2022] Open
Abstract
The blood-brain barrier (BBB) plays a pivotal role in brain health and disease. In the BBB, brain microvascular endothelial cells (BMECs) are connected by tight junctions which regulate paracellular transport, and express specialized transporter systems which regulate transcellular transport. However, existing in vitro models of the BBB display variable accuracy across a wide range of characteristics including gene/protein expression and barrier function. Here, we use an isogenic family of fluorescently-labeled iPSC-derived BMEC-like cells (iBMECs) and brain pericyte-like cells (iPCs) within two-dimensional confluent monolayers (2D) and three-dimensional (3D) tissue-engineered microvessels to explore how 3D microenvironment regulates gene expression and function of the in vitro BBB. We show that 3D microenvironment (shear stress, cell-ECM interactions, and cylindrical geometry) increases BBB phenotype and endothelial identity, and alters angiogenic and cytokine responses in synergy with pericyte co-culture. Tissue-engineered microvessels incorporating junction-labeled iBMECs enable study of the real-time dynamics of tight junctions during homeostasis and in response to physical and chemical perturbations.
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Affiliation(s)
- Raleigh M Linville
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA. .,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA.
| | - Matthew B Sklar
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA
| | - Gabrielle N Grifno
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA.,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Renée F Nerenberg
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA.,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Justin Zhou
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA.,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Robert Ye
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA
| | - Jackson G DeStefano
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA.,Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Zhaobin Guo
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA
| | - Ria Jha
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA.,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - John J Jamieson
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA.,Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Nan Zhao
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA
| | - Peter C Searson
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA. .,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA. .,Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, USA.
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Linville RM, Komin A, Lan X, DeStefano JG, Chu C, Liu G, Walczak P, Hristova K, Searson PC. Reversible blood-brain barrier opening utilizing the membrane active peptide melittin in vitro and in vivo. Biomaterials 2021; 275:120942. [PMID: 34147718 DOI: 10.1016/j.biomaterials.2021.120942] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 04/21/2021] [Accepted: 05/28/2021] [Indexed: 10/21/2022]
Abstract
The blood-brain barrier (BBB) tightly controls entry of molecules and cells into the brain, restricting the delivery of therapeutics. Blood-brain barrier opening (BBBO) utilizes reversible disruption of cell-cell junctions between brain microvascular endothelial cells to enable transient entry into the brain. Here, we demonstrate that melittin, a membrane active peptide present in bee venom, supports transient BBBO. From endothelial and neuronal viability studies, we first identify the accessible concentration range for BBBO. We then use a tissue-engineered model of the human BBB to optimize dosing and elucidate the mechanism of opening. Melittin and other membrane active variants transiently increase paracellular permeability via disruption of cell-cell junctions that result in transient focal leaks. To validate the results from the tissue-engineered model, we then demonstrate that transient BBBO can be reproduced in a mouse model. We identify a minimum clinically effective intra-arterial dose of 3 μM min melittin, which is reversible within one day and neurologically safe. Melittin-induced BBBO represents a novel technology for delivery of therapeutics into the brain.
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Affiliation(s)
- Raleigh M Linville
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Alexander Komin
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA; Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Xiaoyan Lan
- Department of Diagnostic Radiology & Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Jackson G DeStefano
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA; Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Chengyan Chu
- Department of Diagnostic Radiology & Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Guanshu Liu
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Piotr Walczak
- Department of Diagnostic Radiology & Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kalina Hristova
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA; Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Peter C Searson
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA; Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, USA.
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Linville RM, DeStefano JG, Nerenberg RF, Grifno GN, Ye R, Gallagher E, Searson PC. Long-Term Cryopreservation Preserves Blood-Brain Barrier Phenotype of iPSC-Derived Brain Microvascular Endothelial Cells and Three-Dimensional Microvessels. Mol Pharm 2020; 17:3425-3434. [PMID: 32787285 PMCID: PMC9923881 DOI: 10.1021/acs.molpharmaceut.0c00484] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Brain microvascular endothelial cells derived from induced pluripotent stem cells (dhBMECs) are a scalable and reproducible resource for studies of the human blood-brain barrier, including mechanisms and strategies for drug delivery. Confluent monolayers of dhBMECs recapitulate key in vivo functions including tight junctions to limit paracellular permeability and efflux and nutrient transport to regulate transcellular permeability. Techniques for cryopreservation of dhBMECs have been reported; however, functional validation studies after long-term cryopreservation have not been extensively performed. Here, we characterize dhBMECs after 1 year of cryopreservation using selective purification on extracellular matrix-treated surfaces and ROCK inhibition. One-year cryopreserved dhBMECs maintain functionality of tight junctions, efflux pumps, and nutrient transporters with stable protein localization and gene expression. Cryopreservation is associated with a decrease in the yield of adherent cells and unique responses to cell stress, resulting in altered paracellular permeability of Lucifer yellow. Additionally, cryopreserved dhBMECs reliably form functional three-dimensional microvessels independent of cryopreservation length, with permeabilities lower than non-cryopreserved two-dimensional models. Long-term cryopreservation of dhBMECs offers key advantages including increased scalability, reduced batch-to-batch effects, the ability to conduct well-controlled follow up studies, and support of multisite collaboration from the same cell stock, all while maintaining phenotype for screening pharmaceutical agents.
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Affiliation(s)
- Raleigh M. Linville
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, Maryland 21218, United States; Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland 21218, United States
| | - Jackson G. DeStefano
- Institute for Nanobiotechnology and Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Reneé F. Nerenberg
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, Maryland 21218, United States; Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland 21218, United States
| | - Gabrielle N. Grifno
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, Maryland 21218, United States; Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland 21218, United States
| | - Robert Ye
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Erin Gallagher
- Institute for Nanobiotechnology and Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Peter C. Searson
- Institute for Nanobiotechnology and Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States; Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland 21218, United States
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Linville RM, DeStefano JG, Sklar MB, Chu C, Walczak P, Searson PC. Modeling hyperosmotic blood-brain barrier opening within human tissue-engineered in vitro brain microvessels. J Cereb Blood Flow Metab 2020; 40:1517-1532. [PMID: 31394959 PMCID: PMC7308510 DOI: 10.1177/0271678x19867980] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
As the majority of therapeutic agents do not cross the blood-brain barrier (BBB), transient BBB opening (BBBO) is one strategy to enable delivery into the brain for effective treatment of CNS disease. Intra-arterial infusion of the hyperosmotic agent mannitol reversibly opens the BBB; however, widespread clinical use has been limited due to the variability in outcomes. The current model for mannitol-induced BBBO assumes a transient but homogeneous increase in permeability; however, the details are poorly understood. To elucidate the mechanism of hyperosmotic opening at the cellular level, we developed a tissue-engineered microvessel model using stem cell-derived human brain microvascular endothelial cells (BMECs) perturbed with clinically relevant mannitol doses. This model recapitulates physiological shear stress, barrier function, microvessel geometry, and cell-matrix interactions. Using live-cell imaging, we show that mannitol results in dose-dependent and spatially heterogeneous increases in paracellular permeability through the formation of transient focal leaks. Additionally, we find that the degree of BBB opening and subsequent recovery is modulated by treatment with basic fibroblast growth factor. These results show that tissue-engineered BBB models can provide insight into the mechanisms of BBBO and hence improve the reproducibility of hyperosmotic therapies for treatment of CNS disease.
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Affiliation(s)
- Raleigh M Linville
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA.,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Jackson G DeStefano
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA.,Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Matt B Sklar
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA
| | - Chengyan Chu
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Piotr Walczak
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Peter C Searson
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA.,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA.,Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, USA
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Bogorad MI, DeStefano JG, Linville RM, Wong AD, Searson PC. Cerebrovascular plasticity: Processes that lead to changes in the architecture of brain microvessels. J Cereb Blood Flow Metab 2019; 39:1413-1432. [PMID: 31208241 PMCID: PMC6681538 DOI: 10.1177/0271678x19855875] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The metabolic demands of the brain are met by oxygen and glucose, supplied by a complex hierarchical network of microvessels (arterioles, capillaries, and venules). Transient changes in neural activity are accommodated by local dilation of arterioles or capillaries to increase cerebral blood flow and hence nutrient availability. Transport and communication between the circulation and the brain is regulated by the brain microvascular endothelial cells that form the blood-brain barrier. Under homeostatic conditions, there is very little turnover in brain microvascular endothelial cells, and the cerebrovascular architecture is largely static. However, changes in the brain microenvironment, due to environmental factors, disease, or trauma, can result in additive or subtractive changes in cerebrovascular architecture. Additions occur by angiogenesis or vasculogenesis, whereas subtractions occur by vascular pruning, injury, or endothelial cell death. Here we review the various processes that lead to changes in the cerebrovascular architecture, including sustained changes in the brain microenvironment, development and aging, and injury, disease, and repair.
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Affiliation(s)
- Max I Bogorad
- 1 Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA.,2 Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Jackson G DeStefano
- 1 Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA.,2 Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Raleigh M Linville
- 1 Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA.,3 Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Andrew D Wong
- 1 Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA.,2 Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Peter C Searson
- 1 Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA.,2 Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, USA.,3 Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
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DeStefano JG, Jamieson JJ, Linville RM, Searson PC. Benchmarking in vitro tissue-engineered blood-brain barrier models. Fluids Barriers CNS 2018; 15:32. [PMID: 30514389 PMCID: PMC6280508 DOI: 10.1186/s12987-018-0117-2] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 11/11/2018] [Indexed: 12/13/2022] Open
Abstract
The blood–brain barrier (BBB) plays a key role in regulating transport into and out of the brain. With increasing interest in the role of the BBB in health and disease, there have been significant advances in the development of in vitro models. The value of these models to the research community is critically dependent on recapitulating characteristics of the BBB in humans or animal models. However, benchmarking in vitro models is surprisingly difficult since much of our knowledge of the structure and function of the BBB comes from in vitro studies. Here we describe a set of parameters that we consider a starting point for benchmarking and validation. These parameters are associated with structure (ultrastructure, wall shear stress, geometry), microenvironment (basement membrane and extracellular matrix), barrier function (transendothelial electrical resistance, permeability, efflux transport), cell function (expression of BBB markers, turnover), and co-culture with other cell types (astrocytes and pericytes). In suggesting benchmarks, we rely primarily on imaging or direct measurements in humans and animal models.
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Affiliation(s)
- Jackson G DeStefano
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA.,Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - John J Jamieson
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA.,Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Raleigh M Linville
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA.,Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Peter C Searson
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA. .,Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, USA. .,120 Croft Hall, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD, 21218, USA.
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DeStefano JG, Xu ZS, Williams AJ, Yimam N, Searson PC. Effect of shear stress on iPSC-derived human brain microvascular endothelial cells (dhBMECs). Fluids Barriers CNS 2017; 14:20. [PMID: 28774343 PMCID: PMC5543552 DOI: 10.1186/s12987-017-0068-z] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 07/20/2017] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The endothelial cells that form the lumen of capillaries and microvessels are an important component of the blood-brain barrier. Cell phenotype is regulated by transducing a range of biomechanical and biochemical signals in the local microenvironment. Here we report on the role of shear stress in modulating the morphology, motility, proliferation, apoptosis, and protein and gene expression, of confluent monolayers of human brain microvascular endothelial cells derived from induced pluripotent stem cells. METHODS To assess the response of derived human brain microvascular endothelial cells (dhBMECs) to shear stress, confluent monolayers were formed in a microfluidic device. Monolayers were subjected to a shear stress of 4 or 12 dyne cm-2 for 40 h. Static conditions were used as the control. Live cell imaging was used to assess cell morphology, cell speed, persistence, and the rates of proliferation and apoptosis as a function of time. In addition, immunofluorescence imaging and protein and gene expression analysis of key markers of the blood-brain barrier were performed. RESULTS Human brain microvascular endothelial cells exhibit a unique phenotype in response to shear stress compared to static conditions: (1) they do not elongate and align, (2) the rates of proliferation and apoptosis decrease significantly, (3) the mean displacement of individual cells within the monolayer over time is significantly decreased, (4) there is no cytoskeletal reorganization or formation of stress fibers within the cell, and (5) there is no change in expression levels of key blood-brain barrier markers. CONCLUSIONS The characteristic response of dhBMECs to shear stress is significantly different from human and animal-derived endothelial cells from other tissues, suggesting that this unique phenotype that may be important in maintenance of the blood-brain barrier. The implications of this work are that: (1) in confluent monolayers of dhBMECs, tight junctions are formed under static conditions, (2) the formation of tight junctions decreases cell motility and prevents any morphological transitions, (3) flow serves to increase the contact area between cells, resulting in very low cell displacement in the monolayer, (4) since tight junctions are already formed under static conditions, increasing the contact area between cells does not cause upregulation in protein and gene expression of BBB markers, and (5) the increase in contact area induced by flow makes barrier function more robust.
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Affiliation(s)
- Jackson G DeStefano
- Institute for Nanobiotechnology, Johns Hopkins University, 100 Croft Hall, 3400 North Charles Street, Baltimore, MD, 21218, USA.,Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Zinnia S Xu
- Institute for Nanobiotechnology, Johns Hopkins University, 100 Croft Hall, 3400 North Charles Street, Baltimore, MD, 21218, USA.,Department of Biomedical Engineering, Johns Hopkins University, 720 Rutland Avenue, Baltimore, MD, 21205, USA
| | - Ashley J Williams
- Institute for Nanobiotechnology, Johns Hopkins University, 100 Croft Hall, 3400 North Charles Street, Baltimore, MD, 21218, USA
| | - Nahom Yimam
- Institute for Nanobiotechnology, Johns Hopkins University, 100 Croft Hall, 3400 North Charles Street, Baltimore, MD, 21218, USA
| | - Peter C Searson
- Institute for Nanobiotechnology, Johns Hopkins University, 100 Croft Hall, 3400 North Charles Street, Baltimore, MD, 21218, USA. .,Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA.
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DeStefano JG, Williams A, Wnorowski A, Yimam N, Searson PC, Wong AD. Real-time quantification of endothelial response to shear stress and vascular modulators. Integr Biol (Camb) 2017; 9:362-374. [PMID: 28345713 PMCID: PMC5490251 DOI: 10.1039/c7ib00023e] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Quiescence is commonly used to describe the inactive state of endothelial cells (ECs) in monolayers that have reached homeostasis. Experimentally quiescence is usually described in terms of the relative change in cell activity (e.g. turnover, speed, etc.) in response to a perturbation (e.g. solute, shear stress, etc.). The objective of this study is to provide new insight into EC quiescence by quantitatively defining the morphology and activity of confluent cell monolayers in response to shear stress and vascular modulators. Confluent monolayers of human umbilical vein ECs (HUVECs) were subjected to a range of shear stresses (4-16 dyne cm-2) under steady flow. Using phase contrast, time-lapse microscopy and image analysis, we quantified EC morphology, speed, proliferation, and apoptosis rates over time and detected differences in monolayer responses under various media conditions: basal media supplemented with growth factors, interleukin-8, or cyclic AMP. In all conditions, we observed a transition from cobblestone to spindle-like morphology in a dose-dependent manner due to shear stress. Cyclic AMP enhanced the elongation and alignment of HUVECs due to shear stress and reduced steady state cell speed. We observed the lowest proliferation rates below 8 dyne cm-2 and found that growth factors and cyclic AMP reduced proliferation and apoptosis; interleukin-8 similarly decreased proliferation, but increased apoptosis. We have quantified the response of ECs in confluent monolayers to shear stress and vascular modulators in terms of morphology, speed, proliferation and apoptosis and have established quantifiable metrics of cell activity to define vascular quiescence under shear stress.
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Affiliation(s)
- Jackson G DeStefano
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA.
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