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Beheshtizadeh N, Gharibshahian M, Bayati M, Maleki R, Strachan H, Doughty S, Tayebi L. Vascular endothelial growth factor (VEGF) delivery approaches in regenerative medicine. Biomed Pharmacother 2023; 166:115301. [PMID: 37562236 DOI: 10.1016/j.biopha.2023.115301] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 07/28/2023] [Accepted: 08/05/2023] [Indexed: 08/12/2023] Open
Abstract
The utilization of growth factors in the process of tissue regeneration has garnered significant interest and has been the subject of extensive research. However, despite the fervent efforts invested in recent clinical trials, a considerable number of these studies have produced outcomes that are deemed unsatisfactory. It is noteworthy that the trials that have yielded the most satisfactory outcomes have exhibited a shared characteristic, namely, the existence of a mechanism for the regulated administration of growth factors. Despite the extensive exploration of drug delivery vehicles and their efficacy in delivering certain growth factors, the development of a reliable predictive approach for the delivery of delicate growth factors like Vascular Endothelial Growth Factor (VEGF) remains elusive. VEGF plays a crucial role in promoting angiogenesis; however, the administration of VEGF demands a meticulous approach as it necessitates precise localization and transportation to a specific target tissue. This process requires prolonged and sustained exposure to a low concentration of VEGF. Inaccurate administration of drugs, either through off-target effects or inadequate delivery, may heighten the risk of adverse reactions and potentially result in tumorigenesis. At present, there is a scarcity of technologies available for the accurate encapsulation of VEGF and its subsequent sustained and controlled release. The objective of this review is to present and assess diverse categories of VEGF administration mechanisms. This paper examines various systems, including polymeric, liposomal, hydrogel, inorganic, polyplexes, and microfluidic, and evaluates the appropriate dosage of VEGF for multiple applications.
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Affiliation(s)
- Nima Beheshtizadeh
- Department of Tissue Engineering, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Iran; Regenerative Medicine group (REMED), Universal Scientific Education and Research Network (USERN), Tehran, Iran.
| | - Maliheh Gharibshahian
- Department of Tissue Engineering, School of Medicine, Shahroud University of Medical Sciences, Shahroud, Iran; Regenerative Medicine group (REMED), Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Mohammad Bayati
- Department of Phytochemistry, Medicinal Plants and Drugs Research Institute, Shahid Beheshti University, Tehran, Iran
| | - Reza Maleki
- Department of Chemical Technologies, Iranian Research Organization for Science and Technology (IROST), P.O. Box 33535111, Tehran, Iran.
| | - Hannah Strachan
- Marquette University School of Dentistry, Milwaukee, WI 53233, USA
| | - Sarah Doughty
- Marquette University School of Dentistry, Milwaukee, WI 53233, USA
| | - Lobat Tayebi
- Marquette University School of Dentistry, Milwaukee, WI 53233, USA
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2
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Zhang C, Li T, Yin S, Gao M, He H, Li Y, Jiang D, Shi M, Wang J, Yu L. Monocytes deposit migrasomes to promote embryonic angiogenesis. Nat Cell Biol 2022; 24:1726-1738. [PMID: 36443426 DOI: 10.1038/s41556-022-01026-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 10/12/2022] [Indexed: 11/30/2022]
Abstract
Pro-angiogenic factors are key regulators of angiogenesis. Here we report that highly migratory cells patrol the area of capillary formation in chick embryo chorioallantoic membrane. These cells deposit migrasomes on their migration tracks, creating migrasome-enriched areas. Single-cell sequencing identified these cells as monocytes. Depletion of monocytes impairs capillary formation. Quantitative mass spectrometry analysis reveals that monocyte migrasomes are enriched with pro-angiogenic factors. Purified migrasomes promote capillary formation and monocyte recruitment in vivo, and endothelial cell tube formation and monocyte chemotaxis in vitro. Knockdown or knockout of TSPAN4 reduces migrasome formation and impairs capillary formation and monocyte recruitment. Mechanistically, monocytes promote angiogenesis via VEGFA and CXCL12 in migrasomes. In summary, monocytes deposit migrasomes enriched in pro-angiogenic factors to promote angiogenesis.
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Affiliation(s)
- Cuifang Zhang
- State Key Laboratory of Membrane Biology, Tsinghua University-Peking University Joint Centre for Life Sciences, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, China
| | - Tianqi Li
- School of Life Science, Tsinghua University, Beijing, China
| | - Shuyao Yin
- State Key Laboratory of Membrane Biology, Tsinghua University-Peking University Joint Centre for Life Sciences, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, China
| | - Mingyi Gao
- State Key Laboratory of Membrane Biology, Tsinghua University-Peking University Joint Centre for Life Sciences, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, China
| | - Helen He
- State Key Laboratory of Membrane Biology, Tsinghua University-Peking University Joint Centre for Life Sciences, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, China
| | - Ying Li
- State Key Laboratory of Membrane Biology, Tsinghua University-Peking University Joint Centre for Life Sciences, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, China
| | - Dong Jiang
- State Key Laboratory of Membrane Biology, Tsinghua University-Peking University Joint Centre for Life Sciences, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, China
| | - Minghui Shi
- State Key Laboratory of Membrane Biology, Tsinghua University-Peking University Joint Centre for Life Sciences, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jianbin Wang
- School of Life Science, Tsinghua University, Beijing, China
| | - Li Yu
- State Key Laboratory of Membrane Biology, Tsinghua University-Peking University Joint Centre for Life Sciences, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, China.
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3
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Barrasa-Ramos S, Dessalles CA, Hautefeuille M, Barakat AI. Mechanical regulation of the early stages of angiogenesis. J R Soc Interface 2022; 19:20220360. [PMID: 36475392 PMCID: PMC9727679 DOI: 10.1098/rsif.2022.0360] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Favouring or thwarting the development of a vascular network is essential in fields as diverse as oncology, cardiovascular disease or tissue engineering. As a result, understanding and controlling angiogenesis has become a major scientific challenge. Mechanical factors play a fundamental role in angiogenesis and can potentially be exploited for optimizing the architecture of the resulting vascular network. Largely focusing on in vitro systems but also supported by some in vivo evidence, the aim of this Highlight Review is dual. First, we describe the current knowledge with particular focus on the effects of fluid and solid mechanical stimuli on the early stages of the angiogenic process, most notably the destabilization of existing vessels and the initiation and elongation of new vessels. Second, we explore inherent difficulties in the field and propose future perspectives on the use of in vitro and physics-based modelling to overcome these difficulties.
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Affiliation(s)
- Sara Barrasa-Ramos
- LadHyX, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, Palaiseau, France
| | - Claire A. Dessalles
- LadHyX, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, Palaiseau, France
| | - Mathieu Hautefeuille
- Laboratoire de Biologie du Développement (UMR7622), Institut de Biologie Paris Seine, Sorbonne Université, Paris, France,Facultad de Ciencias, Universidad Nacional Autónoma de México, CDMX, Mexico
| | - Abdul I. Barakat
- LadHyX, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, Palaiseau, France
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4
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Eleftheriadou D, Berg M, Phillips JB, Shipley RJ. A combined experimental and computational framework to evaluate the behavior of therapeutic cells for peripheral nerve regeneration. Biotechnol Bioeng 2022; 119:1980-1996. [PMID: 35445744 PMCID: PMC9323509 DOI: 10.1002/bit.28105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 03/22/2022] [Accepted: 04/08/2022] [Indexed: 11/08/2022]
Abstract
Recent studies have explored the potential of tissue‐mimetic scaffolds in encouraging nerve regeneration. One of the major determinants of the regenerative success of cellular nerve repair constructs (NRCs) is the local microenvironment, particularly native low oxygen conditions which can affect implanted cell survival and functional performance. In vivo, cells reside in a range of environmental conditions due to the spatial gradients of nutrient concentrations that are established. Here we evaluate in vitro the differences in cellular behavior that such conditions induce, including key biological features such as oxygen metabolism, glucose consumption, cell death, and vascular endothelial growth factor secretion. Experimental measurements are used to devise and parameterize a mathematical model that describes the behavior of the cells. The proposed model effectively describes the interactions between cells and their microenvironment and could in the future be extended, allowing researchers to compare the behavior of different therapeutic cells. Such a combinatorial approach could be used to accelerate the clinical translation of NRCs by identifying which critical design features should be optimized when fabricating engineered nerve repair conduits.
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Affiliation(s)
- D Eleftheriadou
- Centre for Nerve Engineering, University College London, London, WC1E 6B.,Department of Pharmacology, UCL School of Pharmacy, University College London, London, WC1N 1AX.,Department of Mechanical Engineering, University College London, London, WC1E 7JE
| | - M Berg
- Centre for Nerve Engineering, University College London, London, WC1E 6B.,Department of Mechanical Engineering, University College London, London, WC1E 7JE
| | - J B Phillips
- Centre for Nerve Engineering, University College London, London, WC1E 6B.,Department of Pharmacology, UCL School of Pharmacy, University College London, London, WC1N 1AX
| | - R J Shipley
- Centre for Nerve Engineering, University College London, London, WC1E 6B.,Department of Mechanical Engineering, University College London, London, WC1E 7JE
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5
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Inverting angiogenesis with interstitial flow and chemokine matrix-binding affinity. Sci Rep 2022; 12:4237. [PMID: 35273299 PMCID: PMC8913640 DOI: 10.1038/s41598-022-08186-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 02/15/2022] [Indexed: 11/30/2022] Open
Abstract
The molecular signaling pathways that orchestrate angiogenesis have been widely studied, but the role of biophysical cues has received less attention. Interstitial flow is unavoidable in vivo, and has been shown to dramatically change the neovascular patterns, but the mechanisms by which flow regulates angiogenesis remain poorly understood. Here, we study the complex interactions between interstitial flow and the affinity for matrix binding of different chemokine isoforms. Using a computational model, we find that changing the matrix affinity of the chemokine isoform can invert the effect of interstitial flow on angiogenesis—from preferential growth in the direction of the flow when the chemokine is initially matrix-bound to preferential flow against the flow when it is unbound. Although fluid forces signal endothelial cells directly, our data suggests a mechanism for the inversion based on biotransport arguments only, and offers a potential explanation for experimental results in which interstitial flow produced preferential vessel growth with and against the flow. Our results point to a particularly intricate effect of interstitial flow on angiogenesis in the tumor microenvironment, where the vessel network geometry and the interstitial flow patterns are complex.
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6
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Coy R, Berg M, Phillips JB, Shipley RJ. Modelling-informed cell-seeded nerve repair construct designs for treating peripheral nerve injuries. PLoS Comput Biol 2021; 17:e1009142. [PMID: 34237052 PMCID: PMC8266098 DOI: 10.1371/journal.pcbi.1009142] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 06/02/2021] [Indexed: 11/19/2022] Open
Abstract
Millions of people worldwide are affected by peripheral nerve injuries (PNI), involving billions of dollars in healthcare costs. Common outcomes for patients include paralysis and loss of sensation, often leading to lifelong pain and disability. Engineered Neural Tissue (EngNT) is being developed as an alternative to the current treatments for large-gap PNIs that show underwhelming functional recovery in many cases. EngNT repair constructs are composed of a stabilised hydrogel cylinder, surrounded by a sheath of material, to mimic the properties of nerve tissue. The technology also enables the spatial seeding of therapeutic cells in the hydrogel to promote nerve regeneration. The identification of mechanisms leading to maximal nerve regeneration and to functional recovery is a central challenge in the design of EngNT repair constructs. Using in vivo experiments in isolation is costly and time-consuming, offering a limited insight on the mechanisms underlying the performance of a given repair construct. To bridge this gap, we derive a cell-solute model and apply it to the case of EngNT repair constructs seeded with therapeutic cells which produce vascular endothelial growth factor (VEGF) under low oxygen conditions to promote vascularisation in the construct. The model comprises a set of coupled non-linear diffusion-reaction equations describing the evolving cell population along with its interactions with oxygen and VEGF fields during the first 24h after transplant into the nerve injury site. This model allows us to evaluate a wide range of repair construct designs (e.g. cell-seeding strategy, sheath material, culture conditions), the idea being that designs performing well over a short timescale could be shortlisted for in vivo trials. In particular, our results suggest that seeding cells beyond a certain density threshold is detrimental regardless of the situation considered, opening new avenues for future nerve tissue engineering.
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Affiliation(s)
- Rachel Coy
- Department of Mechanical Engineering, UCL, London, United Kingdom
- Center for Nerve Engineering, UCL, London, United Kingdom
| | - Maxime Berg
- Department of Mechanical Engineering, UCL, London, United Kingdom
- Center for Nerve Engineering, UCL, London, United Kingdom
- * E-mail:
| | - James B. Phillips
- Center for Nerve Engineering, UCL, London, United Kingdom
- Department of Pharmacology, School of Pharmacy, UCL, London, United Kingdom
| | - Rebecca J. Shipley
- Department of Mechanical Engineering, UCL, London, United Kingdom
- Center for Nerve Engineering, UCL, London, United Kingdom
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7
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Zhan K, Bai L, Hu Q. Selective induction of sprouting and intussusception is associated with the concentration distributions of oxygen and hypoxia-induced VEGF. Microvasc Res 2020; 132:104041. [DOI: 10.1016/j.mvr.2020.104041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 07/09/2020] [Accepted: 07/09/2020] [Indexed: 12/17/2022]
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8
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Mamer SB, Wittenkeller A, Imoukhuede PI. VEGF-A splice variants bind VEGFRs with differential affinities. Sci Rep 2020; 10:14413. [PMID: 32879419 PMCID: PMC7468149 DOI: 10.1038/s41598-020-71484-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 08/04/2020] [Indexed: 12/29/2022] Open
Abstract
Vascular endothelial growth factor A (VEGF-A) and its binding to VEGFRs is an important angiogenesis regulator, especially the earliest-known isoform, VEGF-A165a. Yet several additional splice variants play prominent roles in regulating angiogenesis in health and in vascular disease, including VEGF-A121 and an anti-angiogenic variant, VEGF-A165b. Few studies have attempted to distinguish these forms from their angiogenic counterparts, experimentally. Previous studies of VEGF-A:VEGFR binding have measured binding kinetics for VEGFA165 and VEGF-A121, but binding kinetics of the other two pro- and all anti-angiogenic splice variants are not known. We measured the binding kinetics for VEGF-A165, -A165b, and -A121 with VEGFR1 and VEGF-R2 using surface plasmon resonance. We validated our methods by reproducing the known affinities between VEGF-A165a:VEGFR1 and VEGF-A165a:VEGFR2, 1.0 pM and 10 pM respectively, and validated the known affinity VEGF-A121:VEGFR2 as KD = 0.66 nM. We found that VEGF-A121 also binds VEGFR1 with an affinity KD = 3.7 nM. We further demonstrated that the anti-angiogenic variant, VEGF-A165b selectively prefers VEGFR2 binding at an affinity = 0.67 pM while binding VEGFR1 with a weaker affinity-KD = 1.4 nM. These results suggest that the - A165b anti-angiogenic variant would preferentially bind VEGFR2. These discoveries offer a new paradigm for understanding VEGF-A, while further stressing the need to take care in differentiating the splice variants in all future VEGF-A studies.
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Affiliation(s)
- Spencer B Mamer
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
| | - Ashley Wittenkeller
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - P I Imoukhuede
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
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9
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Li J, Liu X, Zang S, Zhou J, Zhang F, Sun B, Qi D, Li X, Kong J, Jin D, Yang X, Luo Y, Lu Y, Lin B, Niu W, Liu T. Small extracellular vesicle-bound vascular endothelial growth factor secreted by carcinoma-associated fibroblasts promotes angiogenesis in a bevacizumab-resistant manner. Cancer Lett 2020; 492:71-83. [PMID: 32860852 DOI: 10.1016/j.canlet.2020.08.030] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 08/12/2020] [Accepted: 08/20/2020] [Indexed: 01/08/2023]
Abstract
The blood vessel growth inhibitor bevacizumab targets vascular endothelial growth factor (VEGF), a crucial regulator of angiogenesis. Recently, small extracellular vesicles (sEVs) have been demonstrated to be important vehicles in the transport of growth factors to target cells. In this study, we isolated primary carcinoma-associated fibroblasts (CAFs) from four human oral squamous cell carcinoma (OSCC) specimens. Compared with other non-extracellular vesicle components, CAF-derived sEVs were found to be the main regulators of angiogenesis. The ability of CAF sEVs to activate VEGF receptor 2 (VEGFR2) signaling in human umbilical vein endothelial cells (HUVEC) was dependent on the association between sEVs and VEGF. In addition, sEV-bound VEGF secreted by CAFs further activated VEGFR2 signaling in HUVEC in a bevacizumab-resistant manner. VEGF was found to interact with heparan sulfate proteoglycans on the CAF sEV surface and could be released by heparinase I/III. The bioactivity of the dissociated VEGF was retained in vitro and in vivo and could be neutralized by bevacizumab. These findings suggest that the combined use of heparinase and bevacizumab might inhibit angiogenesis in patients with high levels of sEV-bound VEGF.
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Affiliation(s)
- Jiao Li
- School of Stomatology, Dalian Medical University, No.9 West Section, South Road of Lvshun, Dalian, 116044, China
| | - Xue Liu
- School of Stomatology, Dalian Medical University, No.9 West Section, South Road of Lvshun, Dalian, 116044, China
| | - Shizhu Zang
- Biomedical Engineering Department, Dalian Medical University, No.9 West Section, South Road of Lvshun, Dalian, 116044, China
| | - Jiasheng Zhou
- School of Stomatology, Dalian Medical University, No.9 West Section, South Road of Lvshun, Dalian, 116044, China
| | - Fuyin Zhang
- Department of Oral Surgery, The Second Affiliated Hospital, Dalian Medical University, No.467 Zhongshan Road, Dalian, 116023, China
| | - Bo Sun
- Department of Oral Surgery, The Second Affiliated Hospital, Dalian Medical University, No.467 Zhongshan Road, Dalian, 116023, China
| | - Dongyuan Qi
- Department of Oral Surgery, The First Affiliated Hospital of Dalian Medical University, No.222 Zhongshan Road, Dalian, 116023, China
| | - Xiaojie Li
- School of Stomatology, Dalian Medical University, No.9 West Section, South Road of Lvshun, Dalian, 116044, China
| | - Jing Kong
- School of Stomatology, Dalian Medical University, No.9 West Section, South Road of Lvshun, Dalian, 116044, China
| | - Dong Jin
- School of Stomatology, Dalian Medical University, No.9 West Section, South Road of Lvshun, Dalian, 116044, China
| | - Xuesong Yang
- Department of Biochemistry and Molecular Biology, Liaoning Provincial Core Lab of Glycobiology and Glycoengineering, Dalian Medical University, No.9 West Section, South Road of Lvshun, Dalian, 116044, China
| | - Yong Luo
- Faculty of Chemical, Environmental and Biological Science and Technology, Dalian Technology University, No.2 Linggong Road, Ganjingzi District, Dalian, 116023, China
| | - Yao Lu
- Department of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, No.457 Zhongshan Road, Dalian, 116023, China
| | - Bingcheng Lin
- Department of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, No.457 Zhongshan Road, Dalian, 116023, China
| | - Weidong Niu
- School of Stomatology, Dalian Medical University, No.9 West Section, South Road of Lvshun, Dalian, 116044, China.
| | - Tingjiao Liu
- School of Stomatology, Dalian Medical University, No.9 West Section, South Road of Lvshun, Dalian, 116044, China.
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10
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Yu C, Dou T, Liu Y, Liu R. Clinical value of TV-CDS combined with serum tumor markers in diagnosis of ovarian cancer. Oncol Lett 2020; 20:2028-2034. [PMID: 32724450 DOI: 10.3892/ol.2020.11705] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 04/14/2020] [Indexed: 11/06/2022] Open
Abstract
Clinical application value was investigated of transvaginal color Doppler ultrasound (TV-CDS) combined with serum tumor markers carbohydrate antigen 125 (CA125), vascular endothelial growth factor (VEGF) and osteopontin (OPN) in the diagnosis of ovarian cancer (OC). One hundred and six patients with OC [malignant tumor group (MTG)] and fifty patients with benign ovarian diseases [benign control group (BCG)] were selected. Both groups of patients underwent TV-CDS examination. The lesion morphology and internal structure were observed, and the tumor blood flow signal, resistance index (RI) and pulsability index (PI) under ultrasound were determined. Serum CA125 was detected by electrochemiluminescence, and VEGF and OPN levels were detected by enzyme-linked immunosorbent assay. The incidence of irregular lesion morphology, unclear boundary, uneven internal echo, microcalcification and side-acoustic images in OC group (OCG) was significantly higher than that in BCG (P<0.01). As for blood flow grading, most patients in the MTG were in grade II and III, while most patients in the BCG were in grade 0. Compared with BCG, the flow RI and PI in the OCG were significantly reduced (P<0.01). The levels of serum CA125, VEGF and OPN in OCG were significantly higher than those in BCG. The expression levels of serum CA125, VEGF and OPN in OC patients with clinical high stage (stage III and IV), poorly differentiated, ascites, recurrence and metastasis were significantly higher than those in patients with clinical low stage (stage I and II), well differentiated, no ascites and no recurrence and metastasis (P<0.05). With the disappearance of the tumor or the decrease of tumor load, the serum marker levels after treatment were significantly lower than that before treatment (P<0.05). The sensitivity and accuracy of the combined examination in the diagnosis of OC were obviously improved compared with the single and partial combined examinations (P<0.05). In conclusion, combined examination can significantly improve the sensitivity and accuracy of OC, which is conducive to early diagnosis and clinical intervention of OC.
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Affiliation(s)
- Chunying Yu
- Department of Ultrasonic Medicine, The Third People's Hospital of Qingdao, Qingdao, Shandong 266041, P.R. China
| | - Ting Dou
- Department of Ultrasonic Medicine, The Third People's Hospital of Qingdao, Qingdao, Shandong 266041, P.R. China
| | - Yun Liu
- Department of Ultrasonic Medicine, The Third People's Hospital of Qingdao, Qingdao, Shandong 266041, P.R. China
| | - Ruirong Liu
- Department of Ultrasonic Medicine, The Third People's Hospital of Qingdao, Qingdao, Shandong 266041, P.R. China
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11
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Eyeing the Extracellular Matrix in Vascular Development and Microvascular Diseases and Bridging the Divide between Vascular Mechanics and Function. Int J Mol Sci 2020; 21:ijms21103487. [PMID: 32429045 PMCID: PMC7278940 DOI: 10.3390/ijms21103487] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 05/12/2020] [Accepted: 05/13/2020] [Indexed: 12/20/2022] Open
Abstract
The extracellular matrix (ECM) is critical in all aspects of vascular development and health: supporting cell anchorage, providing structure, organization and mechanical stability, and serving as a sink for growth factors and sustained survival signals. Abnormal changes in ECM protein expression, organization, and/or properties, and the ensuing changes in vascular compliance affect vasodilator responses, microvascular pressure transmission, and collateral perfusion. The changes in microvascular compliance are independent factors initiating, driving, and/or exacerbating a plethora of microvascular diseases of the eye including diabetic retinopathy (DR) and vitreoretinopathy, retinopathy of prematurity (ROP), wet age-related macular degeneration (AMD), and neovascular glaucoma. Congruently, one of the major challenges with most vascular regenerative therapies utilizing localized growth factor, endothelial progenitor, or genetically engineered cell delivery, is the regeneration of blood vessels with physiological compliance properties. Interestingly, vascular cells sense physical forces, including the stiffness of their ECM, through mechanosensitive integrins, their associated proteins and the actomyosin cytoskeleton, which generates biochemical signals that culminate in a rapid expression of matricellular proteins such as cellular communication network 1 (CCN1) and CCN2 (aka connective tissue growth factor or CTGF). Loss or gain of function of these proteins alters genetic programs of cell growth, ECM biosynthesis, and intercellular signaling, that culminate in changes in cell behavior, polarization, and barrier function. In particular, the function of the matricellular protein CCN2/CTGF is critical during retinal vessel development and regeneration wherein new blood vessels form and invest a preformed avascular neural retina following putative gradients of matrix stiffness. These observations underscore the need for further in-depth characterization of the ECM-derived cues that dictate structural and functional properties of the microvasculature, along with the development of new therapeutic strategies addressing the ECM-dependent regulation of pathophysiological stiffening of blood vessels in ischemic retinopathies.
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12
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Rubin JB, Lagas JS, Broestl L, Sponagel J, Rockwell N, Rhee G, Rosen SF, Chen S, Klein RS, Imoukhuede P, Luo J. Sex differences in cancer mechanisms. Biol Sex Differ 2020; 11:17. [PMID: 32295632 PMCID: PMC7161126 DOI: 10.1186/s13293-020-00291-x] [Citation(s) in RCA: 128] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Accepted: 03/18/2020] [Indexed: 02/07/2023] Open
Abstract
We now know that cancer is many different diseases, with great variation even within a single histological subtype. With the current emphasis on developing personalized approaches to cancer treatment, it is astonishing that we have not yet systematically incorporated the biology of sex differences into our paradigms for laboratory and clinical cancer research. While some sex differences in cancer arise through the actions of circulating sex hormones, other sex differences are independent of estrogen, testosterone, or progesterone levels. Instead, these differences are the result of sexual differentiation, a process that involves genetic and epigenetic mechanisms, in addition to acute sex hormone actions. Sexual differentiation begins with fertilization and continues beyond menopause. It affects virtually every body system, resulting in marked sex differences in such areas as growth, lifespan, metabolism, and immunity, all of which can impact on cancer progression, treatment response, and survival. These organismal level differences have correlates at the cellular level, and thus, males and females can fundamentally differ in their protections and vulnerabilities to cancer, from cellular transformation through all stages of progression, spread, and response to treatment. Our goal in this review is to cover some of the robust sex differences that exist in core cancer pathways and to make the case for inclusion of sex as a biological variable in all laboratory and clinical cancer research. We finish with a discussion of lab- and clinic-based experimental design that should be used when testing whether sex matters and the appropriate statistical models to apply in data analysis for rigorous evaluations of potential sex effects. It is our goal to facilitate the evaluation of sex differences in cancer in order to improve outcomes for all patients.
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Affiliation(s)
- Joshua B Rubin
- Department of Pediatrics, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, MO, 63110, USA.
- Department of Neuroscience, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, MO, 63110, USA.
| | - Joseph S Lagas
- Department of Pediatrics, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, MO, 63110, USA
| | - Lauren Broestl
- Department of Pediatrics, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, MO, 63110, USA
| | - Jasmin Sponagel
- Department of Pediatrics, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, MO, 63110, USA
| | - Nathan Rockwell
- Department of Pediatrics, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, MO, 63110, USA
| | - Gina Rhee
- Department of Pediatrics, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, MO, 63110, USA
| | - Sarah F Rosen
- Department of Medicine, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, MO, 63110, USA
| | - Si Chen
- Department of Biomedical Engineering, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, MO, 63110, USA
| | - Robyn S Klein
- Department of Neuroscience, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, MO, 63110, USA
- Department of Medicine, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, MO, 63110, USA
| | - Princess Imoukhuede
- Department of Biomedical Engineering, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, MO, 63110, USA
| | - Jingqin Luo
- Department of Surgery, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, MO, 63110, USA
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13
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Rauff A, LaBelle SA, Strobel HA, Hoying JB, Weiss JA. Imaging the Dynamic Interaction Between Sprouting Microvessels and the Extracellular Matrix. Front Physiol 2019; 10:1011. [PMID: 31507428 PMCID: PMC6713949 DOI: 10.3389/fphys.2019.01011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 07/22/2019] [Indexed: 12/21/2022] Open
Abstract
Thorough understanding of growth and evolution of tissue vasculature is fundamental to many fields of medicine including cancer therapy, wound healing, and tissue engineering. Angiogenesis, the growth of new vessels from existing ones, is dynamically influenced by a variety of environmental factors, including mechanical and biophysical factors, chemotactic factors, proteolysis, and interaction with stromal cells. Yet, dynamic interactions between neovessels and their environment are difficult to study with traditional fixed time imaging techniques. Advancements in imaging technologies permit time-series and volumetric imaging, affording the ability to visualize microvessel growth over 3D space and time. Time-lapse imaging has led to more informative investigations of angiogenesis. The environmental factors implicated in angiogenesis span a wide range of signals. Neovessels advance through stromal matrices by forming attachments and pulling and pushing on their microenvironment, reorganizing matrix fibers, and inducing large deformations of the surrounding stroma. Concurrently, neovessels secrete proteolytic enzymes to degrade their basement membrane, create space for new vessels to grow, and release matrix-bound cytokines. Growing neovessels also respond to a host of soluble and matrix-bound growth factors, and display preferential growth along a cytokine gradient. Lastly, stromal cells such as macrophages and mesenchymal stem cells (MSCs) interact directly with neovessels and their surrounding matrix to facilitate sprouting, vessel fusion, and tissue remodeling. This review highlights how time-lapse imaging techniques advanced our understanding of the interaction of blood vessels with their environment during sprouting angiogenesis. The technology provides means to characterize the evolution of microvessel behavior, providing new insights and holding great promise for further research on the process of angiogenesis.
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Affiliation(s)
- Adam Rauff
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, United States
| | - Steven A. LaBelle
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, United States
| | - Hannah A. Strobel
- Innovations Laboratory, Advanced Solutions Life Sciences, Manchester, NH, United States
| | - James B. Hoying
- Innovations Laboratory, Advanced Solutions Life Sciences, Manchester, NH, United States
| | - Jeffrey A. Weiss
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, United States
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Single-Cell Receptor Quantification of an In Vitro Coculture Angiogenesis Model Reveals VEGFR, NRP1, Tie2, and PDGFR Regulation and Endothelial Heterogeneity. Processes (Basel) 2019. [DOI: 10.3390/pr7060356] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Angiogenesis, the formation of new blood vessels from pre-existing ones, is essential for both normal development and numerous pathologies. Systems biology has offered a unique approach to study angiogenesis by profiling tyrosine kinase receptors (RTKs) that regulate angiogenic processes and computationally modeling RTK signaling pathways. Historically, this systems biology approach has been applied on ex vivo angiogenesis assays, however, these assays are difficult to quantify and limited in their potential of temporal analysis. In this study, we adopted a simple two-dimensional angiogenesis assay comprised of human umbilical vein endothelial cells (HUVECs) and human dermal fibroblasts (HDFs) and examined temporal dynamics of a panel of six RTKs and cell heterogeneity up to 17 days. We observed ~2700 VEGFR1 (vascular endothelial growth factor receptor 1) per cell on 24-h-old cocultured HDF plasma membranes, which do not express VEGFR when cultured alone. We observed 4000–8100 VEGFR2 per cell on cocultured HUVEC plasma membranes throughout endothelial tube formation. We showed steady increase of platelet-derived growth factor receptors (PDGFRs) on cocultured HDF plasma membranes, and more interestingly, 1900–2900 PDGFRβ per plasma membrane were found on HUVECs within the first six hours of coculturing. These quantitative findings will offer us insights into molecular regulation during angiogenesis and help assess in vitro tube formation models and their physiological relevance.
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15
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Mapping Tyrosine Kinase Receptor Dimerization to Receptor Expression and Ligand Affinities. Processes (Basel) 2019. [DOI: 10.3390/pr7050288] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Tyrosine kinase receptor (RTK) ligation and dimerization is a key mechanism for translating external cell stimuli into internal signaling events. This process is critical to several key cell and physiological processes, such as in angiogenesis and embryogenesis, among others. While modulating RTK activation is a promising therapeutic target, RTK signaling axes have been shown to involve complicated interactions between ligands and receptors both within and across different protein families. In angiogenesis, for example, several signaling protein families, including vascular endothelial growth factors and platelet-derived growth factors, exhibit significant cross-family interactions that can influence pathway activation. Computational approaches can provide key insight to detangle these signaling pathways but have been limited by the sparse knowledge of these cross-family interactions. Here, we present a framework for studying known and potential non-canonical interactions. We constructed generalized models of RTK ligation and dimerization for systems of two, three and four receptor types and different degrees of cross-family ligation. Across each model, we developed parameter-space maps that fully determine relative pathway activation for any set of ligand-receptor binding constants, ligand concentrations and receptor concentrations. Therefore, our generalized models serve as a powerful reference tool for predicting not only known ligand: Receptor axes but also how unknown interactions could alter signaling dimerization patterns. Accordingly, it will drive the exploration of cross-family interactions and help guide therapeutic developments across processes like cancer and cardiovascular diseases, which depend on RTK-mediated signaling.
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16
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Lakatos D, Somfai E, Méhes E, Czirók A. Soluble VEGFR1 signaling guides vascular patterns into dense branching morphologies. J Theor Biol 2018; 456:261-278. [PMID: 30086288 PMCID: PMC6292526 DOI: 10.1016/j.jtbi.2018.08.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 08/01/2018] [Accepted: 08/03/2018] [Indexed: 01/27/2023]
Abstract
Vascular patterning is a key process during development and disease. The diffusive decoy receptor sVEGFR1 (sFlt1) is a known regulator of endothelial cell behavior, yet the mechanism by which it controls vascular structure is little understood. We propose computational models to shed light on how vascular patterning is guided by self-organized gradients of the VEGF/sVEGFR1 factors. We demonstrate that a diffusive inhibitor can generate structures with a dense branching morphology in models where the activator elicits directed growth. Inadequate presence of the inhibitor leads to compact growth, while excessive production of the inhibitor blocks expansion and stabilizes existing structures. Model predictions were compared with time-resolved experimental data obtained from endothelial sprout kinetics in fibrin gels. In the presence of inhibitory antibodies against VEGFR1 vascular sprout density increases while the speed of sprout expansion remains unchanged. Thus, the rate of secretion and stability of extracellular sVEGFR1 can modulate vascular sprout density.
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Affiliation(s)
- Dóra Lakatos
- Department of Biological Physics, Eötvös Loránd University, Budapest, Hungary.
| | - Ellák Somfai
- Institute for Solid State Physics and Optics, Wigner Research Center for Physics, Hungarian Academy of Sciences, Budapest, Hungary
| | - Előd Méhes
- Department of Biological Physics, Eötvös Loránd University, Budapest, Hungary
| | - András Czirók
- Department of Biological Physics, Eötvös Loránd University, Budapest, Hungary; Department of Anatomy & Cell Biology, University of Kansas Medical Center, Kansas City, KS, USA.
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17
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Lee DJ, Rocker AJ, Bardill JR, Shandas R, Park D. A sulfonated reversible thermal gel for the spatiotemporal control of VEGF delivery to promote therapeutic angiogenesis. J Biomed Mater Res A 2018; 106:3053-3064. [PMID: 30295997 DOI: 10.1002/jbm.a.36496] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 06/15/2018] [Accepted: 06/22/2018] [Indexed: 12/23/2022]
Abstract
Despite medical and surgical advancements for the treatment of cardiovascular disease, mortality and morbidity remain high. Therapeutic angiogenesis has been one approach to address the major clinical need for a more effective treatment to restoring blood flow in ischemic organs and tissues, but current progress in angiogenic drug delivery is inadequate at providing sufficient bioavailability without causing safety concerns. An injectable sulfonated reversible thermal gel composed of a polyurea conjugated with poly(N-isopropylacrylamide) and sulfonate groups has been developed for the delivery of angiogenic factors. The thermal gel allowed for the spatiotemporal control of vascular endothelial growth factor release with a decreased initial burst release and reduced release rate in vitro. A subcutaneous injection mouse model was used to evaluate efficacious vascularization and assess the inflammatory response due to a foreign body. Thermal gel injections showed substantial vascularization properties by inducing vessel formation, recruitment and differentiation of vascular endothelial cells, and vessel stabilization by perivascular cells, while infiltrating macrophages due to the thermal gel injections decreased over time. These results demonstrated effective localization and delivery of angiogenic factors for therapeutic angiogenesis. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 3053-3064, 2018.
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Affiliation(s)
- David J Lee
- Department of Bioengineering, University of Colorado Denver Anschutz Medical Campus, 12800 E. 19th Avenue, Aurora, Colorado, 80045
| | - Adam J Rocker
- Department of Bioengineering, University of Colorado Denver Anschutz Medical Campus, 12800 E. 19th Avenue, Aurora, Colorado, 80045
| | - James R Bardill
- Department of Bioengineering, University of Colorado Denver Anschutz Medical Campus, 12800 E. 19th Avenue, Aurora, Colorado, 80045
| | - Robin Shandas
- Department of Bioengineering, University of Colorado Denver Anschutz Medical Campus, 12800 E. 19th Avenue, Aurora, Colorado, 80045
| | - Daewon Park
- Department of Bioengineering, University of Colorado Denver Anschutz Medical Campus, 12800 E. 19th Avenue, Aurora, Colorado, 80045
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18
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Rocha LA, Sousa RA, Learmonth DA, Salgado AJ. The Role of Biomaterials as Angiogenic Modulators of Spinal Cord Injury: Mimetics of the Spinal Cord, Cell and Angiogenic Factor Delivery Agents. Front Pharmacol 2018; 9:164. [PMID: 29535633 PMCID: PMC5835322 DOI: 10.3389/fphar.2018.00164] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 02/14/2018] [Indexed: 12/12/2022] Open
Abstract
Spinal cord injury (SCI) represents an extremely debilitating condition for which no efficacious treatment is available. One of the main contributors to the inhospitable environment found in SCI is the vascular disruption that happens at the moment of injury that compromises the blood-spinal cord barrier (BSCB) and triggers a cascade of events that includes infiltration of inflammatory cells, ischemia and intraparenchymal hemorrhage. Due to the unsatisfactory nature of revascularization following SCI, restoring vascular perfusion and the BSCB seems an interesting way of modulating the lesion environment into a regenerative phenotype, with a potential increase in functional recovery. Certain biomaterials possess interesting features to enhance SCI therapies, and in fact have been applied as angiogenic promoters in other pathologies. The present mini-review intends to highlight the contribution that biomaterials could make in the development of novel therapeutic solutions able to restore proper vascularization and the BSCB.
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Affiliation(s)
- Luís A. Rocha
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s – PT Government Associate Laboratory, Braga, Portugal
- Stemmatters, Biotecnologia e Medicina Regenerativa SA, Barco, Portugal
| | - Rui A. Sousa
- Stemmatters, Biotecnologia e Medicina Regenerativa SA, Barco, Portugal
| | | | - António J. Salgado
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s – PT Government Associate Laboratory, Braga, Portugal
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19
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Burazin A, Drapaca CS, Tenti G, Sivaloganathan S. A Poroelasticity Theory Approach to Study the Mechanisms Leading to Elevated Interstitial Fluid Pressure in Solid Tumours. Bull Math Biol 2017; 80:1172-1194. [PMID: 29282596 DOI: 10.1007/s11538-017-0383-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Accepted: 12/14/2017] [Indexed: 10/18/2022]
Abstract
Although the mechanisms responsible for elevated interstitial fluid pressure (IFP) in tumours remain obscure, it seems clear that high IFP represents a barrier to drug delivery (since the resulting adverse pressure gradient implies a reduction in the driving force for transvascular exchange of both fluid and macromolecules). R. Jain and co-workers studied this problem, and although the conclusions drawn from their idealized mathematical models offered useful insights into the causes of elevated IFP, they by no means gave a definitive explanation for this phenomenon. In this paper, we use poroelasticity theory to also develop a macroscopic mathematical model to describe the time evolution of a solid tumour, but focus our attention on the mechanisms responsible for the rise of the IFP, from that for a healthy interstitium to that measured in malignant tumours. In particular, we discuss a number of possible time scales suggested by our mathematical model and propose a tumour-dependent time scale that leads to results in agreement with experimental observations. We apply our mathematical model to simulate the effect of "vascular normalization" (as proposed by Jain in Nat Med 7:987-989, 2001) on the IFP profile and discuss and contrast our conclusions with those of previous work in the literature.
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Affiliation(s)
- Andrijana Burazin
- Mathematical and Computational Sciences, University of Toronto, Mississauga, ON, L5M 5G9, Canada
| | - Corina S Drapaca
- Engineering Science and Mechanics, Pennsylvania State University, University Park, PA, 16802, USA
| | - Giuseppe Tenti
- Applied Mathematics, University of Waterloo, Waterloo, ON, N2L 3G1, Canada
| | - Siv Sivaloganathan
- Applied Mathematics, University of Waterloo, Waterloo, ON, N2L 3G1, Canada.
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20
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Retinal vasculature development in health and disease. Prog Retin Eye Res 2017; 63:1-19. [PMID: 29129724 DOI: 10.1016/j.preteyeres.2017.11.001] [Citation(s) in RCA: 185] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 11/02/2017] [Accepted: 11/06/2017] [Indexed: 12/17/2022]
Abstract
Development of the retinal vasculature is based on highly coordinated signalling between different cell types of the retina, integrating internal metabolic requirements with external influences such as the supply of oxygen and nutrients. The developing mouse retinal vasculature is a useful model system to study these interactions because it is experimentally accessible for intra ocular injections and genetic manipulations, can be easily imaged and develops in a similar fashion to that of humans. Research using this model has provided insights about general principles of angiogenesis as well as pathologies that affect the developing retinal vasculature. In this review, we discuss recent advances in our understanding of the molecular and cellular mechanisms that govern the interactions between neurons, glial and vascular cells in the developing retina. This includes a review of mechanisms that shape the retinal vasculature, such as sprouting angiogenesis, vascular network remodelling and vessel maturation. We also explore how the disruption of these processes in mice can lead to pathology - such as oxygen induced retinopathy - and how this translates to human retinopathy of prematurity.
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21
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Guo M, Shi JH, Wang PL, Shi DZ. Angiogenic Growth Factors for Coronary Artery Disease: Current Status and Prospects. J Cardiovasc Pharmacol Ther 2017; 23:130-141. [PMID: 29025278 DOI: 10.1177/1074248417735399] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Ming Guo
- China Heart Institute of Chinese Medicine, China Academy of Chinese Medical Sciences, Beijing, China
- Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Jun-He Shi
- Department of Periodontics, University of Illinois at Chicago, Chicago, IL, USA
| | - Pei-Li Wang
- China Heart Institute of Chinese Medicine, China Academy of Chinese Medical Sciences, Beijing, China
- Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Da-Zhuo Shi
- China Heart Institute of Chinese Medicine, China Academy of Chinese Medical Sciences, Beijing, China
- Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
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22
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Clegg LE, Mac Gabhann F. A computational analysis of in vivo VEGFR activation by multiple co-expressed ligands. PLoS Comput Biol 2017; 13:e1005445. [PMID: 28319199 PMCID: PMC5378411 DOI: 10.1371/journal.pcbi.1005445] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Revised: 04/03/2017] [Accepted: 03/08/2017] [Indexed: 12/16/2022] Open
Abstract
The splice isoforms of vascular endothelial growth A (VEGF) each have different affinities for the extracellular matrix (ECM) and the coreceptor NRP1, which leads to distinct vascular phenotypes in model systems expressing only a single VEGF isoform. ECM-immobilized VEGF can bind to and activate VEGF receptor 2 (VEGFR2) directly, with a different pattern of site-specific phosphorylation than diffusible VEGF. To date, the way in which ECM binding alters the distribution of isoforms of VEGF and of the related placental growth factor (PlGF) in the body and resulting angiogenic signaling is not well-understood. Here, we extend our previous validated cell-level computational model of VEGFR2 ligation, intracellular trafficking, and site-specific phosphorylation, which captured differences in signaling by soluble and immobilized VEGF, to a multi-scale whole-body framework. This computational systems pharmacology model captures the ability of the ECM to regulate isoform-specific growth factor distribution distinctly for VEGF and PlGF, and to buffer free VEGF and PlGF levels in tissue. We show that binding of immobilized growth factor to VEGF receptors, both on endothelial cells and soluble VEGFR1, is likely important to signaling in vivo. Additionally, our model predicts that VEGF isoform-specific properties lead to distinct profiles of VEGFR1 and VEGFR2 binding and VEGFR2 site-specific phosphorylation in vivo, mediated by Neuropilin-1. These predicted signaling changes mirror those observed in murine systems expressing single VEGF isoforms. Simulations predict that, contrary to the 'ligand-shifting hypothesis,' VEGF and PlGF do not compete for receptor binding at physiological concentrations, though PlGF is predicted to slightly increase VEGFR2 phosphorylation when over-expressed by 10-fold. These results are critical to design of appropriate therapeutic strategies to control VEGF availability and signaling in regenerative medicine applications.
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Affiliation(s)
- Lindsay E. Clegg
- Institute for Computational Medicine, Institute for NanoBioTechnology, and Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Feilim Mac Gabhann
- Institute for Computational Medicine, Institute for NanoBioTechnology, and Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, United States of America
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland, United States of America
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23
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24
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Bodnar M, Guerrero P, Perez-Carrasco R, Piotrowska MJ. Deterministic and Stochastic Study for a Microscopic Angiogenesis Model: Applications to the Lewis Lung Carcinoma. PLoS One 2016; 11:e0155553. [PMID: 27182891 PMCID: PMC4868326 DOI: 10.1371/journal.pone.0155553] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 04/29/2016] [Indexed: 11/24/2022] Open
Abstract
Angiogenesis modelling is an important tool to understand the underlying mechanisms yielding tumour growth. Nevertheless, there is usually a gap between models and experimental data. We propose a model based on the intrinsic microscopic reactions defining the angiogenesis process to link experimental data with previous macroscopic models. The microscopic characterisation can describe the macroscopic behaviour of the tumour, which stability analysis reveals a set of predicted tumour states involving different morphologies. Additionally, the microscopic description also gives a framework to study the intrinsic stochasticity of the reactive system through the resulting Langevin equation. To follow the goal of the paper, we use available experimental information on the Lewis lung carcinoma to infer meaningful parameters for the model that are able to describe the different stages of the tumour growth. Finally we explore the predictive capabilities of the fitted model by showing that fluctuations are determinant for the survival of the tumour during the first week and that available treatments can give raise to new stable tumour dormant states with a reduced vascular network.
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Affiliation(s)
- Marek Bodnar
- Institute of Applied Mathematics and Mechanics, Faculty of Mathematics, Informatics and Mechanics, University of Warsaw, Banacha 2, 02-097 Warsaw, Poland
| | - Pilar Guerrero
- Department of Mathematics, University College London, Gower Street, London WC1E 6BT, United Kingdom
- * E-mail:
| | - Ruben Perez-Carrasco
- Department of Mathematics, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Monika J. Piotrowska
- Institute of Applied Mathematics and Mechanics, Faculty of Mathematics, Informatics and Mechanics, University of Warsaw, Banacha 2, 02-097 Warsaw, Poland
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25
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Metzger CS, Koutsimpelas D, Brieger J. Transcriptional regulation of the VEGF gene in dependence of individual genomic variations. Cytokine 2015. [DOI: 10.1016/j.cyto.2015.07.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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26
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Walpole J, Chappell JC, Cluceru JG, Mac Gabhann F, Bautch VL, Peirce SM. Agent-based model of angiogenesis simulates capillary sprout initiation in multicellular networks. Integr Biol (Camb) 2015; 7:987-97. [PMID: 26158406 PMCID: PMC4558383 DOI: 10.1039/c5ib00024f] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Many biological processes are controlled by both deterministic and stochastic influences. However, efforts to model these systems often rely on either purely stochastic or purely rule-based methods. To better understand the balance between stochasticity and determinism in biological processes a computational approach that incorporates both influences may afford additional insight into underlying biological mechanisms that give rise to emergent system properties. We apply a combined approach to the simulation and study of angiogenesis, the growth of new blood vessels from existing networks. This complex multicellular process begins with selection of an initiating endothelial cell, or tip cell, which sprouts from the parent vessels in response to stimulation by exogenous cues. We have constructed an agent-based model of sprouting angiogenesis to evaluate endothelial cell sprout initiation frequency and location, and we have experimentally validated it using high-resolution time-lapse confocal microscopy. ABM simulations were then compared to a Monte Carlo model, revealing that purely stochastic simulations could not generate sprout locations as accurately as the rule-informed agent-based model. These findings support the use of rule-based approaches for modeling the complex mechanisms underlying sprouting angiogenesis over purely stochastic methods.
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Affiliation(s)
- J Walpole
- Department of Biomedical Engineering, University of Virginia, Virginia, USA.
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27
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Chen S, Guo X, Imarenezor O, Imoukhuede PI. Quantification of VEGFRs, NRP1, and PDGFRs on Endothelial Cells and Fibroblasts Reveals Serum, Intra-Family Ligand, and Cross-Family Ligand Regulation. Cell Mol Bioeng 2015. [DOI: 10.1007/s12195-015-0411-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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28
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Santos-Oliveira P, Correia A, Rodrigues T, Ribeiro-Rodrigues TM, Matafome P, Rodríguez-Manzaneque JC, Seiça R, Girão H, Travasso RDM. The Force at the Tip--Modelling Tension and Proliferation in Sprouting Angiogenesis. PLoS Comput Biol 2015; 11:e1004436. [PMID: 26248210 PMCID: PMC4527825 DOI: 10.1371/journal.pcbi.1004436] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2015] [Accepted: 07/08/2015] [Indexed: 12/24/2022] Open
Abstract
Sprouting angiogenesis, where new blood vessels grow from pre-existing ones, is a complex process where biochemical and mechanical signals regulate endothelial cell proliferation and movement. Therefore, a mathematical description of sprouting angiogenesis has to take into consideration biological signals as well as relevant physical processes, in particular the mechanical interplay between adjacent endothelial cells and the extracellular microenvironment. In this work, we introduce the first phase-field continuous model of sprouting angiogenesis capable of predicting sprout morphology as a function of the elastic properties of the tissues and the traction forces exerted by the cells. The model is very compact, only consisting of three coupled partial differential equations, and has the clear advantage of a reduced number of parameters. This model allows us to describe sprout growth as a function of the cell-cell adhesion forces and the traction force exerted by the sprout tip cell. In the absence of proliferation, we observe that the sprout either achieves a maximum length or, when the traction and adhesion are very large, it breaks. Endothelial cell proliferation alters significantly sprout morphology, and we explore how different types of endothelial cell proliferation regulation are able to determine the shape of the growing sprout. The largest region in parameter space with well formed long and straight sprouts is obtained always when the proliferation is triggered by endothelial cell strain and its rate grows with angiogenic factor concentration. We conclude that in this scenario the tip cell has the role of creating a tension in the cells that follow its lead. On those first stalk cells, this tension produces strain and/or empty spaces, inevitably triggering cell proliferation. The new cells occupy the space behind the tip, the tension decreases, and the process restarts.
Our results highlight the ability of mathematical models to suggest relevant hypotheses with respect to the role of forces in sprouting, hence underlining the necessary collaboration between modelling and molecular biology techniques to improve the current state-of-the-art. Sprouting angiogenesis—a process by which new blood vessels grow from existing ones—is an ubiquitous phenomenon in health and disease of higher organisms, playing a crucial role in organogenesis, wound healing, inflammation, as well as on the onset and progression of over 50 different diseases such as cancer, rheumatoid arthritis and diabetes. Mathematical models have the ability to suggest relevant hypotheses with respect to the mechanisms of cell movement and rearrangement within growing vessel sprouts. The inclusion of both biochemical and mechanical processes in a mathematical model of sprouting angiogenesis permits to describe sprout extension as a function of the forces exerted by the cells in the tissue. It also allows to question the regulation of biochemical processes by mechanical forces and vice-versa. In this work we present a compact model of sprouting angiogenesis that includes the mechanical characteristics of the vessel and the tissue. We use this model to suggest the mechanism for the regulation of proliferation within sprout formation. We conclude that the tip cell has the role of creating a tension in the cells that follow its lead. On those first cells of the stalk, this tension produces strain and/or empty spaces, inevitably triggering cell proliferation. The new cells occupy the space behind the tip, the tension decreases, and the process restarts. The modelling strategy used, deemed phase-field, permits to describe the evolution of the shape of different domains in complex systems. It is focused on the movement of the interfaces between the domains, and not on an exhaustive description of the transport properties within each domain. For this reason, it requires a reduced number of parameters, and has been used extensively in modelling other biological phenomena such as tumor growth. The coupling of mechanical and biochemical processes in a compact mathematical model of angiogenesis will enable the study of lumen formation and aneurisms in the near future. Also, this framework will allow the study of the action of flow in vessel remodelling, since local forces can readily be coupled with cell movement to obtain the final vessel morphology.
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Affiliation(s)
| | - António Correia
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Tiago Rodrigues
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Teresa M Ribeiro-Rodrigues
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Paulo Matafome
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- Department of Complementary Sciences, Coimbra Health School (ESTeSC), Instituto Politécnico de Coimbra, Coimbra, Portugal
| | | | - Raquel Seiça
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Henrique Girão
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Rui D. M. Travasso
- CFisUC, Department of Physics, University of Coimbra, Coimbra, Portugal
- * E-mail:
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Clegg LW, Mac Gabhann F. Site-Specific Phosphorylation of VEGFR2 Is Mediated by Receptor Trafficking: Insights from a Computational Model. PLoS Comput Biol 2015; 11:e1004158. [PMID: 26067165 PMCID: PMC4466579 DOI: 10.1371/journal.pcbi.1004158] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 01/25/2015] [Indexed: 02/05/2023] Open
Abstract
Matrix-binding isoforms and non-matrix-binding isoforms of vascular endothelial growth factor (VEGF) are both capable of stimulating vascular remodeling, but the resulting blood vessel networks are structurally and functionally different. Here, we develop and validate a computational model of the binding of soluble and immobilized ligands to VEGF receptor 2 (VEGFR2), the endosomal trafficking of VEGFR2, and site-specific VEGFR2 tyrosine phosphorylation to study differences in induced signaling between these VEGF isoforms. In capturing essential features of VEGFR2 signaling and trafficking, our model suggests that VEGFR2 trafficking parameters are largely consistent across multiple endothelial cell lines. Simulations demonstrate distinct localization of VEGFR2 phosphorylated on Y1175 and Y1214. This is the first model to clearly show that differences in site-specific VEGFR2 activation when stimulated with immobilized VEGF compared to soluble VEGF can be accounted for by altered trafficking of VEGFR2 without an intrinsic difference in receptor activation. The model predicts that Neuropilin-1 can induce differences in the surface-to-internal distribution of VEGFR2. Simulations also show that ligated VEGFR2 and phosphorylated VEGFR2 levels diverge over time following stimulation. Using this model, we identify multiple key levers that alter how VEGF binding to VEGFR2 results in different coordinated patterns of multiple downstream signaling pathways. Specifically, simulations predict that VEGF immobilization, interactions with Neuropilin-1, perturbations of VEGFR2 trafficking, and changes in expression or activity of phosphatases acting on VEGFR2 all affect the magnitude, duration, and relative strength of VEGFR2 phosphorylation on tyrosines 1175 and 1214, and they do so predictably within our single consistent model framework. Vascular endothelial growth factor (VEGF) is an important regulator of blood vessel growth. To date, therapies attempting to harness the VEGF system to promote blood vessel growth (e.g. for wound healing or ischemic disease) have achieved only limited success. To improve VEGF-based therapies, we need to better understand how VEGF promotes development of functional blood vessels. We have developed a computational model of VEGF binding to the receptor VEGFR2, trafficking of VEGFR2 through endosomal compartments in the cell, and activation of VEGFR2 on several tyrosine residues. The pattern of tyrosines activated on VEGFR2 influences cell behavior, promoting cell survival, proliferation, or migration. The combination of these cues influences the diameter of vessels, degree of branching, and leakiness of the resultant vessel network. Our model shows that changes in VEGFR2 trafficking as a result of VEGF immobilization to the extracellular matrix are sufficient to describe observed changes in the pattern of VEGFR2 activation compared to stimulation with purely soluble VEGF. This model can be used to predict how VEGF immobilization, interactions with co-receptors or proteins that deactivate VEGFR2, and changes to VEGFR2 trafficking can be tuned to promote development of functional blood vessel networks for tissue engineering applications.
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Affiliation(s)
- Lindsay Wendel Clegg
- Institute for Computational Medicine and Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, United States of America
- * E-mail:
| | - Feilim Mac Gabhann
- Institute for Computational Medicine and Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, United States of America
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland, United States of America
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30
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Abstract
The vascular network carries blood throughout the body, delivering oxygen to tissues and providing a pathway for communication between distant organs. The network is hierarchical and structured, but also dynamic, especially at the smaller scales. Remodeling of the microvasculature occurs in response to local changes in oxygen, gene expression, cell-cell communication, and chemical and mechanical stimuli from the microenvironment. These local changes occur as a result of physiological processes such as growth and exercise, as well as acute and chronic diseases including stroke, cancer, and diabetes, and pharmacological intervention. While the vasculature is an important therapeutic target in many diseases, drugs designed to inhibit vascular growth have achieved only limited success, and no drug has yet been approved to promote therapeutic vascular remodeling. This highlights the challenges involved in identifying appropriate therapeutic targets in a system as complex as the vasculature. Systems biology approaches provide a means to bridge current understanding of the vascular system, from detailed signaling dynamics measured in vitro and pre-clinical animal models of vascular disease, to a more complete picture of vascular regulation in vivo. This will translate to an improved ability to identify multi-component biomarkers for diagnosis, prognosis, and monitoring of therapy that are easy to measure in vivo, as well as better drug targets for specific disease states. In this review, we summarize systems biology approaches that have advanced our understanding of vascular function and dysfunction in vivo, with a focus on computational modeling.
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Affiliation(s)
- Lindsay E Clegg
- Institute for Computational Medicine and Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.
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31
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Murfee WL, Sweat RS, Tsubota KI, Mac Gabhann F, Khismatullin D, Peirce SM. Applications of computational models to better understand microvascular remodelling: a focus on biomechanical integration across scales. Interface Focus 2015; 5:20140077. [PMID: 25844149 DOI: 10.1098/rsfs.2014.0077] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Microvascular network remodelling is a common denominator for multiple pathologies and involves both angiogenesis, defined as the sprouting of new capillaries, and network patterning associated with the organization and connectivity of existing vessels. Much of what we know about microvascular remodelling at the network, cellular and molecular scales has been derived from reductionist biological experiments, yet what happens when the experiments provide incomplete (or only qualitative) information? This review will emphasize the value of applying computational approaches to advance our understanding of the underlying mechanisms and effects of microvascular remodelling. Examples of individual computational models applied to each of the scales will highlight the potential of answering specific questions that cannot be answered using typical biological experimentation alone. Looking into the future, we will also identify the needs and challenges associated with integrating computational models across scales.
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Affiliation(s)
- Walter L Murfee
- Department of Biomedical Engineering , Tulane University , 500 Lindy Boggs Energy Center, New Orleans, LA 70118 , USA
| | - Richard S Sweat
- Department of Biomedical Engineering , Tulane University , 500 Lindy Boggs Energy Center, New Orleans, LA 70118 , USA
| | - Ken-Ichi Tsubota
- Department of Mechanical Engineering , Chiba University , 1-33 Yayoi, Inage, Chiba 263-8522 , Japan
| | - Feilim Mac Gabhann
- Department of Biomedical Engineering , Johns Hopkins University , 3400 North Charles Street, Baltimore, MD 21218 , USA ; Department of Materials Science and Engineering , Johns Hopkins University , 3400 North Charles Street, Baltimore, MD 21218 , USA ; Institute for Computational Medicine , Johns Hopkins University , 3400 North Charles Street, Baltimore, MD 21218 , USA
| | - Damir Khismatullin
- Department of Biomedical Engineering , Tulane University , 500 Lindy Boggs Energy Center, New Orleans, LA 70118 , USA
| | - Shayn M Peirce
- Department of Biomedical Engineering , University of Virginia , 415 Lane Road, Charlottesville, VA 22903 , USA
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32
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Mehdizadeh H, Somo SI, Bayrak ES, Brey EM, Cinar A. Design of Polymer Scaffolds for Tissue Engineering Applications. Ind Eng Chem Res 2015. [DOI: 10.1021/ie503133e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Hamidreza Mehdizadeh
- Illinois Institute of Technology, 3300 S Federal Street, Chicago, Illinois 60616, United States
| | - Sami I. Somo
- Illinois Institute of Technology, 3300 S Federal Street, Chicago, Illinois 60616, United States
| | - Elif S. Bayrak
- Illinois Institute of Technology, 3300 S Federal Street, Chicago, Illinois 60616, United States
| | - Eric M. Brey
- Illinois Institute of Technology, 3300 S Federal Street, Chicago, Illinois 60616, United States
| | - Ali Cinar
- Illinois Institute of Technology, 3300 S Federal Street, Chicago, Illinois 60616, United States
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33
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Blois SM, Conrad ML, Freitag N, Barrientos G. Galectins in angiogenesis: consequences for gestation. J Reprod Immunol 2014; 108:33-41. [PMID: 25622880 DOI: 10.1016/j.jri.2014.12.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 11/26/2014] [Accepted: 12/03/2014] [Indexed: 12/25/2022]
Abstract
Members of the galectin family have been shown to exert several roles in the context of reproduction. They contribute to placentation, maternal immune regulation and facilitate angiogenesis encompassing decidualisation and placenta formation during pregnancy. In the context of neo-vascularisation, galectins have been shown to augment signalling pathways that lead to endothelial cell activation, cell proliferation, migration and tube formation in vitro in addition to angiogenesis in vivo. Angiogenesis during gestation ensures not only proper foetal growth and development, but also maternal health. Consequently, restriction of placental blood flow has major consequences for both foetus and mother, leading to pregnancy diseases. In this review we summarise both the established and the emerging roles of galectin in angiogenesis and discuss the possible implications during healthy and pathological gestation.
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Affiliation(s)
- Sandra M Blois
- Universitätsmedizin Berlin, Charité-Center 12 Internal Medicine and Dermatology, Medizinische Klinik mit Schwerpunkt Psychosomatik, Reproductive Medicine Research Group, Berlin, Germany.
| | - Melanie L Conrad
- Universitätsmedizin Berlin, Charité-Center 12 Internal Medicine and Dermatology, Medizinische Klinik mit Schwerpunkt Psychosomatik, Reproductive Medicine Research Group, Berlin, Germany
| | - Nancy Freitag
- Universitätsmedizin Berlin, Charité-Center 12 Internal Medicine and Dermatology, Medizinische Klinik mit Schwerpunkt Psychosomatik, Reproductive Medicine Research Group, Berlin, Germany
| | - Gabriela Barrientos
- Laboratorio de Medicina Experimental, Hospital Alemán, Buenos Aires, Argentina
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34
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Abstract
Pericellular proteases have long been associated with cancer invasion and metastasis due to their ability to degrade extracellular matrix components. Recent studies demonstrate that proteases also modulate tumor progression and metastasis through highly regulated and complex processes involving cleavage, processing, or shedding of cell adhesion molecules, growth factors, cytokines, and kinases. In this review, we address how cancer cells, together with their surrounding microenvironment, regulate pericellular proteolysis. We dissect the multitude of mechanisms by which pericellular proteases contribute to cancer progression and discuss how this knowledge can be integrated into therapeutic opportunities.
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Affiliation(s)
- Lisa Sevenich
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, New York, 10065, USA
| | - Johanna A Joyce
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, New York, 10065, USA
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35
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Abstract
Growth factors (GFs) are major regulatory proteins that can govern cell fate, migration, and organization. Numerous aspects of the cell milieu can modulate cell responses to GFs, and GF regulation is often achieved by the native extracellular matrix (ECM). For example, the ECM can sequester GFs and thereby control GF bioavailability. In addition, GFs can exert distinct effects depending on whether they are sequestered in solution, at two-dimensional interfaces, or within three-dimensional matrices. Understanding how the context of GF sequestering impacts cell function in the native ECM can instruct the design of soluble or insoluble GF sequestering moieties, which can then be used in a variety of bioengineering applications. This Feature Article provides an overview of the natural mechanisms of GF sequestering in the cell milieu, and reviews the recent bioengineering approaches that have sequestered GFs to modulate cell function. Results to date demonstrate that the cell response to GF sequestering depends on the affinity of the sequestering interaction, the spatial proximity of sequestering in relation to cells, the source of the GF (supplemented or endogenous), and the phase of the sequestering moiety (soluble or insoluble). We highlight the importance of context for the future design of biomaterials that can leverage endogenous molecules in the cell milieu and mitigate the need for supplemented factors.
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Affiliation(s)
- David G. Belair
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI USA
| | - Ngoc Nhi Le
- Department of Material Science, University of Wisconsin, Madison, WI USA
| | - William L. Murphy
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI USA
- Department of Material Science, University of Wisconsin, Madison, WI USA
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36
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Finley SD, Chu LH, Popel AS. Computational systems biology approaches to anti-angiogenic cancer therapeutics. Drug Discov Today 2014; 20:187-97. [PMID: 25286370 DOI: 10.1016/j.drudis.2014.09.026] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 08/05/2014] [Accepted: 09/29/2014] [Indexed: 01/06/2023]
Abstract
Angiogenesis is an exquisitely regulated process that is required for physiological processes and is also important in numerous diseases. Tumors utilize angiogenesis to generate the vascular network needed to supply the cancer cells with nutrients and oxygen, and many cancer drugs aim to inhibit tumor angiogenesis. Anti-angiogenic therapy involves inhibiting multiple cell types, molecular targets, and intracellular signaling pathways. Computational tools are useful in guiding treatment strategies, predicting the response to treatment, and identifying new targets of interest. Here, we describe progress that has been made in applying mathematical modeling and bioinformatics approaches to study anti-angiogenic therapeutics in cancer.
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Affiliation(s)
- Stacey D Finley
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA.
| | - Liang-Hui Chu
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Aleksander S Popel
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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37
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AngioMap is a Novel Image Analysis Algorithm for Assessment of Plasma Cell Distribution Within Bone Marrow Vascular Niche. Appl Immunohistochem Mol Morphol 2014; 22:550-4. [DOI: 10.1097/pai.0b013e318294cb61] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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38
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Belair D, Khalil AS, Miller MJ, Murphy WL. Serum-dependence of affinity-mediated VEGF release from biomimetic microspheres. Biomacromolecules 2014; 15:2038-48. [PMID: 24773176 PMCID: PMC4059260 DOI: 10.1021/bm500177c] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 04/18/2014] [Indexed: 12/29/2022]
Abstract
Vascular endothelial growth factor (VEGF) activity is highly regulated via sequestering within the ECM and cell-demanded proteolysis to release the sequestered VEGF. Numerous studies have demonstrated that VEGF activity mediates cellular events leading to angiogenesis and capillary formation in vivo. This has motivated the study of biomaterials to sustain VEGF release, and in many cases, the materials are inspired by the structure and function of the native ECM. However, there remains a need for materials that can bind to VEGF with high specificity, as the in vivo environment is rich in a variety of growth factors (GFs) and GF-binding moieties. Here we describe a strategy to control VEGF release using hydrogel microspheres with tethered peptides derived from VEGF receptor 2 (VEGFR2). Using biomaterials covalently modified with varying concentrations of two distinct VEGFR2-derived peptides with varying serum stability, we analyzed both biomaterial and environmental variables that influence VEGF release and activity. The presence of tethered VEGF-binding peptides (VBPs) resulted in significantly extended VEGF release relative to control conditions, and the resulting released VEGF significantly increased the expansion of human umbilical vein endothelial cells in culture. VEGF release rates were also strongly influenced by the concentration of serum. The presence of Feline McDonough Sarcoma-like tyrosine kinase 1 (sFlt-1), a serum-borne receptor fragment derived from VEGF receptor 1, increased VEGF release rates, although sFlt-1 was not sufficient to recapitulate the release profile of VEGF in serum. Further, the influence of serum on VEGF release was not due to protease activity or nonspecific VEGF interactions in the presence of serum-borne heparin. VEGF release kinetics correlated well with a generalizable mathematical model describing affinity-mediated release of VEGF from hydrogel microspheres in defined conditions. Modeling results suggest a potential mechanism whereby competition between VEGF and multiple VEGF-binding serum proteins including sFlt-1, soluble kinase insert domain receptor (sKDR), and α2-macroglobulin (α2-M) likely influenced VEGF release from microspheres. The materials and mathematical model described in this approach may be useful in a range of applications in which sustained, biologically active GF release of a specific GF is desirable.
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Affiliation(s)
- David
G. Belair
- Department
of Biomedical Engineering, University of
Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Andrew S. Khalil
- Department
of Biomedical Engineering, University of
Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Michael J. Miller
- Department
of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - William L. Murphy
- Department
of Biomedical Engineering, University of
Wisconsin-Madison, Madison, Wisconsin 53706, United States
- Department
of Orthopedics and Rehabilitation, University
of Wisconsin-Madison, Madison, Wisconsin 53706, United States
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39
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Devika NT, Jaffar Ali BM. Analysing calcium dependent and independent regulation of eNOS in endothelium triggered by extracellular signalling events. MOLECULAR BIOSYSTEMS 2014; 9:2653-64. [PMID: 23954998 DOI: 10.1039/c3mb70258h] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The vascular endothelium, the intima of blood vessels, coordinately interacts with several biochemical factors expressing endothelial nitric oxide synthase (eNOS) to produce nitric oxide (NO), a potent endogenous vasodilator. The present study investigated the regulation of eNOS by multiple molecular signal transduction pathways, namely vascular endothelial growth factor (VEGF-A) and shear stress which are implicated in the process of angiogenesis and vascular remodelling respectively. In response to signal transduction upstream by VEGF-A and shear stress, different signalling pathways mediated by kinases and intracellular calcium potentiates eNOS activation leading to nitric oxide release. Our study revealed a distinct pattern of eNOS activation driven by VEGF-A and shear stress, maintaining the signalling specificity of the respective pathways. A transient response to eNOS activation was observed under VEGF-A and shear stress stimulus when mediated by calcium dependent cascades, whereas a sustained response was produced by calcium independent vascular signalling kinases. Furthermore, we found that the basal arterial shear stress enhanced eNOS activity when stimulated synergistically even at low VEGF-A levels which might be utilized to facilitate specific endothelial cell functions. Moreover, our study revealed that the presence of PI3K imparted transient behaviour to PLCγ1 supporting the hypothesis that regression and formation of tube structures are mediated by PLCγ1 and PI3K respectively in endothelial cells. This fact is corroborated by the absence of transient behaviour when PI3K is inhibited. We therefore obtained subtle insights into the control mechanism governing the role of specific signalling proteins which are obligate for the regulation of endothelial cell function and the consequent modulation of the nitric oxide release pattern.
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Affiliation(s)
- N T Devika
- AU-KBC Research Centre, Madras Institute of Technology, Anna University, Chrompet, Chennai - 600 044, Tamil Nadu, India.
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40
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Vempati P, Popel AS, Mac Gabhann F. Extracellular regulation of VEGF: isoforms, proteolysis, and vascular patterning. Cytokine Growth Factor Rev 2013; 25:1-19. [PMID: 24332926 DOI: 10.1016/j.cytogfr.2013.11.002] [Citation(s) in RCA: 198] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 11/14/2013] [Accepted: 11/19/2013] [Indexed: 12/15/2022]
Abstract
The regulation of vascular endothelial growth factor A (VEGF) is critical to neovascularization in numerous tissues under physiological and pathological conditions. VEGF has multiple isoforms, created by alternative splicing or proteolytic cleavage, and characterized by different receptor-binding and matrix-binding properties. These isoforms are known to give rise to a spectrum of angiogenesis patterns marked by differences in branching, which has functional implications for tissues. In this review, we detail the extensive extracellular regulation of VEGF and the ability of VEGF to dictate the vascular phenotype. We explore the role of VEGF-releasing proteases and soluble carrier molecules on VEGF activity. While proteases such as MMP9 can 'release' matrix-bound VEGF and promote angiogenesis, for example as a key step in carcinogenesis, proteases can also suppress VEGF's angiogenic effects. We explore what dictates pro- or anti-angiogenic behavior. We also seek to understand the phenomenon of VEGF gradient formation. Strong VEGF gradients are thought to be due to decreased rates of diffusion from reversible matrix binding, however theoretical studies show that this scenario cannot give rise to lasting VEGF gradients in vivo. We propose that gradients are formed through degradation of sequestered VEGF. Finally, we review how different aspects of the VEGF signal, such as its concentration, gradient, matrix-binding, and NRP1-binding can differentially affect angiogenesis. We explore how this allows VEGF to regulate the formation of vascular networks across a spectrum of high to low branching densities, and from normal to pathological angiogenesis. A better understanding of the control of angiogenesis is necessary to improve upon limitations of current angiogenic therapies.
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Affiliation(s)
- Prakash Vempati
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Aleksander S Popel
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Feilim Mac Gabhann
- Institute for Computational Medicine and Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.
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41
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Logsdon EA, Finley SD, Popel AS, Mac Gabhann F. A systems biology view of blood vessel growth and remodelling. J Cell Mol Med 2013; 18:1491-508. [PMID: 24237862 PMCID: PMC4190897 DOI: 10.1111/jcmm.12164] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 09/16/2013] [Indexed: 12/29/2022] Open
Abstract
Blood travels throughout the body in an extensive network of vessels – arteries, veins and capillaries. This vascular network is not static, but instead dynamically remodels in response to stimuli from cells in the nearby tissue. In particular, the smallest vessels – arterioles, venules and capillaries – can be extended, expanded or pruned, in response to exercise, ischaemic events, pharmacological interventions, or other physiological and pathophysiological events. In this review, we describe the multi-step morphogenic process of angiogenesis – the sprouting of new blood vessels – and the stability of vascular networks in vivo. In particular, we review the known interactions between endothelial cells and the various blood cells and plasma components they convey. We describe progress that has been made in applying computational modelling, quantitative biology and high-throughput experimentation to the angiogenesis process.
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Affiliation(s)
- Elizabeth A Logsdon
- Institute for Computational Medicine and Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
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42
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Arcondéguy T, Lacazette E, Millevoi S, Prats H, Touriol C. VEGF-A mRNA processing, stability and translation: a paradigm for intricate regulation of gene expression at the post-transcriptional level. Nucleic Acids Res 2013; 41:7997-8010. [PMID: 23851566 PMCID: PMC3783158 DOI: 10.1093/nar/gkt539] [Citation(s) in RCA: 166] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Vascular Endothelial Growth Factor A (VEGF-A) is a potent secreted mitogen crucial for physiological and pathological angiogenesis. Post-transcriptional regulation of VEGF-A occurs at multiple levels. Firstly, alternative splicing gives rise to different transcript variants encoding diverse isoforms that exhibit distinct biological properties with regard to receptor binding and extra-cellular localization. Secondly, VEGF-A mRNA stability is regulated by effectors such as hypoxia or growth factors through the binding of stabilizing and destabilizing proteins at AU-rich elements located in the 3′-untranslated region. Thirdly, translation of VEGF-A mRNA is a controlled process involving alternative initiation codons, internal ribosome entry sites (IRESs), an upstream open reading frame (uORF), miRNA targeting and a riboswitch in the 3′ untranslated region. These different levels of regulation cooperate for the crucial fine-tuning of the expression of VEGF-A variants. This review will be focused on our current knowledge of the complex post-transcriptional regulatory switches that modulate the cellular VEGF-A level, a paradigmatic model of post-transcriptional regulation.
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Affiliation(s)
- Tania Arcondéguy
- Inserm UMR1037, Centre de Recherches en Cancérologie de Toulouse, CHU Rangueil, BP84225, 31432 Toulouse Cedex 4, France and Université Toulouse III Paul-Sabatier, 118 Route de Narbonne, 31400 Toulouse, France
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44
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Walpole J, Papin JA, Peirce SM. Multiscale computational models of complex biological systems. Annu Rev Biomed Eng 2013; 15:137-54. [PMID: 23642247 DOI: 10.1146/annurev-bioeng-071811-150104] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Integration of data across spatial, temporal, and functional scales is a primary focus of biomedical engineering efforts. The advent of powerful computing platforms, coupled with quantitative data from high-throughput experimental methodologies, has allowed multiscale modeling to expand as a means to more comprehensively investigate biological phenomena in experimentally relevant ways. This review aims to highlight recently published multiscale models of biological systems, using their successes to propose the best practices for future model development. We demonstrate that coupling continuous and discrete systems best captures biological information across spatial scales by selecting modeling techniques that are suited to the task. Further, we suggest how to leverage these multiscale models to gain insight into biological systems using quantitative biomedical engineering methods to analyze data in nonintuitive ways. These topics are discussed with a focus on the future of the field, current challenges encountered, and opportunities yet to be realized.
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Affiliation(s)
- Joseph Walpole
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA
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45
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Carlier A, Geris L, Bentley K, Carmeliet G, Carmeliet P, Van Oosterwyck H. MOSAIC: a multiscale model of osteogenesis and sprouting angiogenesis with lateral inhibition of endothelial cells. PLoS Comput Biol 2012; 8:e1002724. [PMID: 23071433 PMCID: PMC3469420 DOI: 10.1371/journal.pcbi.1002724] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 08/18/2012] [Indexed: 01/15/2023] Open
Abstract
The healing of a fracture depends largely on the development of a new blood vessel network (angiogenesis) in the callus. During angiogenesis tip cells lead the developing sprout in response to extracellular signals, amongst which vascular endothelial growth factor (VEGF) is critical. In order to ensure a correct development of the vasculature, the balance between stalk and tip cell phenotypes must be tightly controlled, which is primarily achieved by the Dll4-Notch1 signaling pathway. This study presents a novel multiscale model of osteogenesis and sprouting angiogenesis, incorporating lateral inhibition of endothelial cells (further denoted MOSAIC model) through Dll4-Notch1 signaling, and applies it to fracture healing. The MOSAIC model correctly predicted the bone regeneration process and recapitulated many experimentally observed aspects of tip cell selection: the salt and pepper pattern seen for cell fates, an increased tip cell density due to the loss of Dll4 and an excessive number of tip cells in high VEGF environments. When VEGF concentration was even further increased, the MOSAIC model predicted the absence of a vascular network and fracture healing, thereby leading to a non-union, which is a direct consequence of the mutual inhibition of neighboring cells through Dll4-Notch1 signaling. This result was not retrieved for a more phenomenological model that only considers extracellular signals for tip cell migration, which illustrates the importance of implementing the actual signaling pathway rather than phenomenological rules. Finally, the MOSAIC model demonstrated the importance of a proper criterion for tip cell selection and the need for experimental data to further explore this. In conclusion, this study demonstrates that the MOSAIC model creates enhanced capabilities for investigating the influence of molecular mechanisms on angiogenesis and its relation to bone formation in a more mechanistic way and across different time and spatial scales.
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Affiliation(s)
- Aurélie Carlier
- Biomechanics Section, KU Leuven, Leuven, Belgium
- Prometheus, Division of Skeletal Tissue Engineering, KU Leuven, O&N 1, Leuven, Belgium
- Biomechanics Research Unit, University of Liege, Liege, Belgium
| | - Liesbet Geris
- Prometheus, Division of Skeletal Tissue Engineering, KU Leuven, O&N 1, Leuven, Belgium
- Biomechanics Research Unit, University of Liege, Liege, Belgium
| | - Katie Bentley
- Vascular Biology Lab, Cancer Research UK, London, United Kingdom
| | - Geert Carmeliet
- Clinical and Experimental Endocrinology, KU Leuven, O&N 1, Leuven, Belgium
| | - Peter Carmeliet
- Laboratory of Angiogenesis and Neurovascular link, Vesalius Research Center, VIB, Leuven, Belgium
- Laboratory of Angiogenesis and Neurovascular link, Vesalius Research Center, University of Leuven, Leuven, Belgium
| | - Hans Van Oosterwyck
- Biomechanics Section, KU Leuven, Leuven, Belgium
- Prometheus, Division of Skeletal Tissue Engineering, KU Leuven, O&N 1, Leuven, Belgium
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Simón-Yarza T, Formiga FR, Tamayo E, Pelacho B, Prosper F, Blanco-Prieto MJ. Vascular endothelial growth factor-delivery systems for cardiac repair: an overview. Am J Cancer Res 2012; 2:541-52. [PMID: 22737191 PMCID: PMC3381347 DOI: 10.7150/thno.3682] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Accepted: 12/23/2011] [Indexed: 11/05/2022] Open
Abstract
Since the discovery of the Vascular Endothelial Growth Factor (VEGF) and its leading role in the angiogenic process, this has been seen as a promising molecule for promoting neovascularization in the infarcted heart. However, even though several clinical trials were initiated, no therapeutic effects were observed, due in part to the short half life of this factor when administered directly to the tissue. In this context, drug delivery systems appear to offer a promising strategy to overcome limitations in clinical trials of VEGF.The aim of this paper is to review the principal drug delivery systems that have been developed to administer VEGF in cardiovascular disease. Studies published in the last 5 years are reviewed and the main features of these systems are explained. The tissue engineering concept is introduced as a therapeutic alternative that holds promise for the near future.
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Peirce SM, Mac Gabhann F, Bautch VL. Integration of experimental and computational approaches to sprouting angiogenesis. Curr Opin Hematol 2012; 19:184-91. [PMID: 22406822 PMCID: PMC4132663 DOI: 10.1097/moh.0b013e3283523ea6] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
PURPOSE OF REVIEW We summarize recent experimental and computational studies that investigate molecular and cellular mechanisms of sprouting angiogenesis. We discuss how experimental tools have unveiled new opportunities for computational modeling by providing detailed phenomenological descriptions and conceptual models of cell-level behaviors underpinned by high-quality molecular data. Using recent examples, we show how new understanding results from bridging computational and experimental approaches. RECENT FINDINGS Experimental data extends beyond the tip cell vs. stalk cell paradigm, and involves numerous molecular inputs such as vascular endothelial growth factor and Notch. This data is being used to generate and validate computational models, which can then be used to predict the results of hypothetical experiments that are difficult to perform in the laboratory, and to generate new hypotheses that account for system-wide interactions. As a result of this integration, descriptions of critical gradients of growth factor-receptor complexes have been generated, and new modulators of cell behavior have been described. SUMMARY We suggest that the recent emphasis on the different stages of sprouting angiogenesis, and integration of experimental and computational approaches, should provide a way to manage the complexity of this process and help identify new regulatory paradigms and therapeutic targets.
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Affiliation(s)
- Shayn M. Peirce
- Dept. of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908
| | - Feilim Mac Gabhann
- Dept. of Biomedical Engineering, Johns Hopkins University, Baltimore MD 21218
- Institute for Computational Medicine, Johns Hopkins University, Baltimore MD 21218
| | - Victoria L Bautch
- Dept. of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- McAllister Heart Institute, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
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Abstract
Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis – the growth of new microvessels from existing microvasculature. Angiogenesis is a complex process involving numerous molecular species, and to better understand it, a systems biology approach is necessary. In vivo preclinical experiments in the area of angiogenesis are typically performed in mouse models; this includes drug development targeting VEGF. Thus, to quantitatively interpret such experimental results, a computational model of VEGF distribution in the mouse can be beneficial. In this paper, we present an in silico model of VEGF distribution in mice, determine model parameters from existing experimental data, conduct sensitivity analysis, and test the validity of the model. The multiscale model is comprised of two compartments: blood and tissue. The model accounts for interactions between two major VEGF isoforms (VEGF120 and VEGF164) and their endothelial cell receptors VEGFR-1, VEGFR-2, and co-receptor neuropilin-1. Neuropilin-1 is also expressed on the surface of parenchymal cells. The model includes transcapillary macromolecular permeability, lymphatic transport, and macromolecular plasma clearance. Simulations predict that the concentration of unbound VEGF in the tissue is approximately 50-fold greater than in the blood. These concentrations are highly dependent on the VEGF secretion rate. Parameter estimation was performed to fit the simulation results to available experimental data, and permitted the estimation of VEGF secretion rate in healthy tissue, which is difficult to measure experimentally. The model can provide quantitative interpretation of preclinical animal data and may be used in conjunction with experimental studies in the development of pro- and anti-angiogenic agents. The model approximates the normal tissue as skeletal muscle and includes endothelial cells to represent the vasculature. As the VEGF system becomes better characterized in other tissues and cell types, the model can be expanded to include additional compartments and vascular elements.
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