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Li R, Xiao X, Yan Y, Yu L, Lv C, Zhang Y, Hong T, Zhang H, Wang Y. GPRASP1 loss-of-function links to arteriovenous malformations by endothelial activating GPR4 signals. Brain 2024; 147:1571-1586. [PMID: 37787182 DOI: 10.1093/brain/awad335] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 08/31/2023] [Accepted: 09/15/2023] [Indexed: 10/04/2023] Open
Abstract
Arteriovenous malformations (AVMs) are fast-flow vascular malformations and refer to important causes of intracerebral haemorrhage in young adults. Getting deep insight into the genetic pathogenesis of AVMs is necessary. Herein, we identified two vital missense variants of G protein-coupled receptor (GPCR) associated sorting protein 1 (GPRASP1) in AVM patients for the first time and congruously determined to be loss-of-function variants in endothelial cells. GPRASP1 loss-of-function caused endothelial dysfunction in vitro and in vivo. Endothelial Gprasp1 knockout mice suffered a high probability of cerebral haemorrhage, AVMs and exhibited vascular anomalies in multiple organs. GPR4 was identified to be an effective GPCR binding with GPRASP1 to develop endothelial disorders. GPRASP1 deletion activated GPR4/cAMP/MAPK signalling to disturb endothelial functions, thus contributing to vascular anomalies. Mechanistically, GPRASP1 promoted GPR4 degradation. GPRASP1 enabled GPR4 K63-linked ubiquitination, enhancing the binding of GPR4 and RABGEF1 to activate RAB5 for conversions from endocytic vesicles to endosomes, and subsequently increasing the interactions of GPR4 and ESCRT members to package GPR4 into multivesicular bodies or late endosomes for lysosome degradation. Notably, the GPR4 antagonist NE 52-QQ57 and JNK inhibitor SP600125 effectively rescued the vascular phenotype caused by endothelial Gprasp1 deletion. Our findings provided novel insights into the roles of GPRASP1 in AVMs and hinted at new therapeutic strategies.
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Affiliation(s)
- Ruofei Li
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China
| | - Xiao Xiao
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China
| | - Yupeng Yan
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China
| | - Liang Yu
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China
| | - Cheng Lv
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China
| | - Yu Zhang
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China
| | - Tao Hong
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, China International Neuroscience Institute, Beijing 100053, China
| | - Hongqi Zhang
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, China International Neuroscience Institute, Beijing 100053, China
| | - Yibo Wang
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China
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Al-Smadi MW, Fazekas LA, Varga A, Matrai AA, Aslan S, Beqain A, Al-Khafaji MQM, Bedocs-Barath B, Novak L, Nemeth N. Minor micro-rheological alterations in the presence of an artificial saphenous arteriovenous shunt, as an arteriovenous malformation model in the rat. Clin Hemorheol Microcirc 2024; 87:27-37. [PMID: 38250764 DOI: 10.3233/ch-231825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2024]
Abstract
BACKGROUND Arteriovenous malformations (AVMs) are vascular anomalies characterized by abnormal shunting between arteries and veins. The progression of the AVMs and their hemodynamic and rheological relations are poorly studied, and there is a lack of a feasible experimental model. OBJECTIVE To establish a model that cause only minimal micro-rheological alterations, compared to other AV models. METHODS Sixteen female Sprague Dawley rats were randomly divided into control and AVM groups. End-to-end anastomoses were created between the saphenous veins and arteries to mimic AVM nidus. Hematological and hemorheological parameters were analyzed before surgery and on the 1st, 3rd, 5th, 7th, 9th, and 12th postoperative weeks. RESULTS Compared to sham-operated Control group the AVM group did not show important alterations in hematological parameters nor in erythrocyte aggregation and deformability. However, slightly increased aggregation and moderately decreased deformability values were found, without significant differences. The changes normalized by the 12th postoperative week. CONCLUSIONS The presented rat model of a small-caliber AVM created on saphenous vessels does not cause significant micro-rheological changes. The alterations found were most likely related to the acute phase reactions and not to the presence of a small-caliber shunt. The model seems to be suitable for further studies of AVM progression.
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Affiliation(s)
- Mohammad Walid Al-Smadi
- Department of Operative Techniques and Surgical Research, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- Kalman Laki Doctoral School, University of Debrecen, Debrecen, Hungary
| | - Laszlo Adam Fazekas
- Department of Operative Techniques and Surgical Research, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- Doctoral School of Clinical Medicine, University of Debrecen, Debrecen, Hungary
| | - Adam Varga
- Department of Operative Techniques and Surgical Research, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- Doctoral School of Clinical Medicine, University of Debrecen, Debrecen, Hungary
| | - Adam Attila Matrai
- Department of Operative Techniques and Surgical Research, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- Doctoral School of Clinical Medicine, University of Debrecen, Debrecen, Hungary
| | - Siran Aslan
- Department of Operative Techniques and Surgical Research, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Anas Beqain
- Department of Operative Techniques and Surgical Research, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Mustafa Qais Muhsin Al-Khafaji
- Department of Operative Techniques and Surgical Research, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Barbara Bedocs-Barath
- Department of Operative Techniques and Surgical Research, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- Doctoral School of Clinical Medicine, University of Debrecen, Debrecen, Hungary
| | - Laszlo Novak
- Department of Neurosurgery, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Norbert Nemeth
- Department of Operative Techniques and Surgical Research, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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Ung TH, Belanger K, Hashmi A, Sekar V, Meola A, Chang SD. Microenvironment changes in arteriovenous malformations after stereotactic radiation. Front Hum Neurosci 2022; 16:982190. [PMID: 36590065 PMCID: PMC9797682 DOI: 10.3389/fnhum.2022.982190] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 11/23/2022] [Indexed: 12/23/2022] Open
Abstract
Cerebral arteriovenous malformations are dysplastic vascular tangles with aberrant vascular dynamics and can result significant morbidity and mortality. A myriad of challenges are encountered when treating these lesions and are largely based on nidal size, location, and prior hemorrhage. Currently, stereotactic radiosurgery is an accepted form of treatment for small to medium sized lesions and is especially useful in the treatment of lesions in non-surgically assessable eloquent areas of the brain. Despite overall high rates of nidal obliteration, there is relatively limited understand on the mechanisms that drive the inflammatory and obliterative pathways observed after treatment with stereotactic radiosurgery. This review provides an overview of arteriovenous malformations with respect to stereotactic radiosurgery and the current understanding of the mechanisms that lead to nidal obliteration.
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Affiliation(s)
- Timothy H. Ung
- Department of Neurosurgery, Stanford University, Palo Alto, CA, United States,Department of Neurosurgery, University of Colorado School of Medicine, Aurora, CO, United States,*Correspondence: Timothy H. Ung
| | - Katherine Belanger
- Department of Neurosurgery, University of Colorado School of Medicine, Aurora, CO, United States
| | - Ayesha Hashmi
- Department of Neurosurgery, Stanford University, Palo Alto, CA, United States
| | - Vashisht Sekar
- Department of Neurosurgery, Stanford University, Palo Alto, CA, United States
| | - Antonio Meola
- Department of Neurosurgery, Stanford University, Palo Alto, CA, United States
| | - Steven D. Chang
- Department of Neurosurgery, Stanford University, Palo Alto, CA, United States
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Faqihi F, Stoodley MA, McRobb LS. Externalization of Mitochondrial PDCE2 on Irradiated Endothelium as a Target for Radiation-Guided Drug Delivery and Precision Thrombosis of Pathological Vasculature. Int J Mol Sci 2022; 23:ijms23168908. [PMID: 36012169 PMCID: PMC9408815 DOI: 10.3390/ijms23168908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/08/2022] [Accepted: 08/09/2022] [Indexed: 11/18/2022] Open
Abstract
Endothelial cells are highly sensitive to ionizing radiation, and exposure leads to multiple adaptive changes. Remarkably, part of this response is the translocation of normally intracellular proteins to the cell surface. It is unclear whether this ectopic expression has a protective or deleterious function, but, regardless, these surface-exposed proteins may provide unique discriminatory targets for radiation-guided drug delivery to vascular malformations or tumor vasculature. We investigated the ability of an antibody–thrombin conjugate targeting mitochondrial PDCE2 (E2 subunit of pyruvate dehydrogenase) to induce precision thrombosis on irradiated endothelial cells in a parallel-plate flow system. Click-chemistry was used to create antibody–thrombin conjugates targeting PDCE2 as the vascular targeting agent (VTA). VTAs were injected into the parallel-plate flow system with whole human blood circulating over irradiated cells. The efficacy and specificity of fibrin-thrombus formation was assessed relative to non-irradiated controls. The PDCE2-targeting VTA dose-dependently increased thrombus formation: minimal thrombosis was induced in response to 5 Gy radiation; doses of 15 and 25 Gy induced significant thrombosis with equivalent efficacy. Negligible VTA binding or thrombosis was demonstrated in the absence of radiation or with non-targeted thrombin. PDCE2 represents a unique discriminatory target for radiation-guided drug delivery and precision thrombosis in pathological vasculature.
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Rivera R, Cruz JP, Merino-Osorio C, Rouchaud A, Mounayer C. Brain arteriovenous malformations: A scoping review of experimental models. INTERDISCIPLINARY NEUROSURGERY 2021. [DOI: 10.1016/j.inat.2021.101200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Schimmel K, Ali MK, Tan SY, Teng J, Do HM, Steinberg GK, Stevenson DA, Spiekerkoetter E. Arteriovenous Malformations-Current Understanding of the Pathogenesis with Implications for Treatment. Int J Mol Sci 2021; 22:ijms22169037. [PMID: 34445743 PMCID: PMC8396465 DOI: 10.3390/ijms22169037] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 08/17/2021] [Accepted: 08/18/2021] [Indexed: 12/18/2022] Open
Abstract
Arteriovenous malformations are a vascular anomaly typically present at birth, characterized by an abnormal connection between an artery and a vein (bypassing the capillaries). These high flow lesions can vary in size and location. Therapeutic approaches are limited, and AVMs can cause significant morbidity and mortality. Here, we describe our current understanding of the pathogenesis of arteriovenous malformations based on preclinical and clinical findings. We discuss past and present accomplishments and challenges in the field and identify research gaps that need to be filled for the successful development of therapeutic strategies in the future.
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Affiliation(s)
- Katharina Schimmel
- Division Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, Stanford University, Stanford, CA 94305, USA; (K.S.); (M.K.A.)
- Vera Moulton Wall Center for Pulmonary Vascular Disease, Stanford University, Stanford, CA 94305, USA
| | - Md Khadem Ali
- Division Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, Stanford University, Stanford, CA 94305, USA; (K.S.); (M.K.A.)
- Vera Moulton Wall Center for Pulmonary Vascular Disease, Stanford University, Stanford, CA 94305, USA
| | - Serena Y. Tan
- Department of Pathology, Stanford University, Stanford, CA 94305, USA;
| | - Joyce Teng
- Department of Dermatology, Lucile Packard Children’s Hospital, Stanford University, Stanford, CA 94305, USA;
| | - Huy M. Do
- Department of Radiology (Neuroimaging and Neurointervention), Stanford University, Stanford, CA 94305, USA;
- Department of Neurosurgery and Stanford Stroke Center, Stanford University, Stanford, CA 94305, USA;
| | - Gary K. Steinberg
- Department of Neurosurgery and Stanford Stroke Center, Stanford University, Stanford, CA 94305, USA;
| | - David A. Stevenson
- Department of Pediatrics, Division of Medical Genetics, Stanford University, Stanford, CA 94305, USA;
| | - Edda Spiekerkoetter
- Division Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, Stanford University, Stanford, CA 94305, USA; (K.S.); (M.K.A.)
- Vera Moulton Wall Center for Pulmonary Vascular Disease, Stanford University, Stanford, CA 94305, USA
- Correspondence: ; Tel.: +1-(650)-739-5031
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Gauden AJ, McRobb LS, Lee VS, Subramanian S, Moutrie V, Zhao Z, Stoodley MA. Occlusion of Animal Model Arteriovenous Malformations Using Vascular Targeting. Transl Stroke Res 2019; 11:689-699. [PMID: 31802427 DOI: 10.1007/s12975-019-00759-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 10/22/2019] [Accepted: 11/19/2019] [Indexed: 01/24/2023]
Abstract
Brain arteriovenous malformations (AVMs) are a significant cause of intracerebral hemorrhage in children and young adults. Currently, one third of patients have no viable treatment options. Vascular targeting agents (VTAs) are being designed to deliver pro-thrombotic molecules to the abnormal AVM vessels for rapid occlusion and cure. This study assessed the efficacy of a pro-thrombotic VTA targeting phosphatidylserine (PS) in a radiation-primed AVM animal model. The model AVM was surgically created in rats by anastomosis of the left external jugular vein to the adjacent common carotid artery. After 6 weeks, the AVM was irradiated (20 Gy) using gamma knife surgery (GKS). A PS-targeting VTA was created by conjugation of annexin V with human thrombin and administered intravenously 3 weeks post-GKS or sham. Unconjugated thrombin was used as a non-targeting control. AVM thrombosis and occlusion was monitored 3 weeks later by angiography and histology. Preliminary experiments established a safe dose of active thrombin for systemic administration. Subsequently, a single dose of annexin V-thrombin conjugate (0.77 mg/kg) resulted in angiographic AVM occlusion in sham (75%) and irradiated (63%) animals, while non-targeted thrombin did not. Lowering the conjugate dose (0.38 mg/kg) decreased angiographic AVM occlusion in sham (13%) relative to irradiated (80%) animals (p = 0.03) as did delivery of two consecutive doses of 0.38 mg/kg, 2 days apart (sham (0%); irradiated (78%); p = 0.003). These findings demonstrate efficacy of the PS-targeting VTA and the feasibility of a vascular targeting approach for occlusion of high-flow AVMs. Targeting specificity can be enhanced by radiation-sensitization and VTA dose modification.
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Affiliation(s)
- Andrew J Gauden
- Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Neurosurgery Unit, Suite 201, 2 Technology Place, Sydney, NSW, 2109, Australia
| | - Lucinda S McRobb
- Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Neurosurgery Unit, Suite 201, 2 Technology Place, Sydney, NSW, 2109, Australia
| | - Vivienne S Lee
- Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Neurosurgery Unit, Suite 201, 2 Technology Place, Sydney, NSW, 2109, Australia
| | - Sinduja Subramanian
- Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Neurosurgery Unit, Suite 201, 2 Technology Place, Sydney, NSW, 2109, Australia
| | - Vaughan Moutrie
- Genesis Cancer Care, Macquarie University Hospital, Sydney, 2109, Australia
| | - Zhenjun Zhao
- Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Neurosurgery Unit, Suite 201, 2 Technology Place, Sydney, NSW, 2109, Australia
| | - Marcus A Stoodley
- Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Neurosurgery Unit, Suite 201, 2 Technology Place, Sydney, NSW, 2109, Australia.
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Radiation-Stimulated Translocation of CD166 and CRYAB to the Endothelial Surface Provides Potential Vascular Targets on Irradiated Brain Arteriovenous Malformations. Int J Mol Sci 2019; 20:ijms20235830. [PMID: 31757032 PMCID: PMC6929092 DOI: 10.3390/ijms20235830] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 11/17/2019] [Accepted: 11/19/2019] [Indexed: 01/18/2023] Open
Abstract
Vascular targeting with pro-thrombotic antibody-conjugates is a promising biological treatment for brain arteriovenous malformations (bAVMs). However, targeted drug delivery relies on the identification of unique or overexpressed markers on the surface of a target cell. In the absence of inherent biological markers, stereotactic radiosurgery may be used to prime induction of site-specific and targetable molecular changes on the endothelial surface. To investigate lumen-accessible, endothelial targets induced by radiation, we combined Gamma knife surgery in an AVM animal model with in vivo biotin-labeling and comparative proteomics. Two proteins, αB-crystallin (CRYAB)-a small heat shock protein that normally acts as an intracellular chaperone to misfolded proteins-and activated leukocyte cell adhesion molecule CD166, were further validated for endothelial surface expression after irradiation. Immunostaining of endothelial cells in vitro and rat AVM tissue ex vivo confirmed de novo induction of CRYAB following irradiation (20 Gy). Western analysis demonstrated that CRYAB accumulated intracellularly as a 20 kDa monomer, but, at the cell surface, a novel 65 kDa protein was observed, suggesting radiation stimulates translocation of an atypical CRYAB isoform. In contrast, CD166 had relatively high expression in non-irradiated cells, localized predominantly to the lateral surfaces. Radiation increased CD166 surface exposure by inducing translocation from intercellular junctions to the apical surface without significantly altering total protein levels. These findings reinforce the dynamic molecular changes induced by radiation exposure, particularly at the cell surface, and support further investigation of radiation as a priming mechanism and these molecules as putative targets for focused drug delivery in irradiated tissue.
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9
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Subramanian S, Ugoya SO, Zhao Z, McRobb LS, Grau GE, Combes V, Inglis DW, Gauden AJ, Lee VS, Moutrie V, Santos ED, Stoodley MA. Stable thrombus formation on irradiated microvascular endothelial cells under pulsatile flow: Pre-testing annexin V-thrombin conjugate for treatment of brain arteriovenous malformations. Thromb Res 2018; 167:104-112. [PMID: 29803980 DOI: 10.1016/j.thromres.2018.05.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 04/19/2018] [Accepted: 05/14/2018] [Indexed: 01/30/2023]
Abstract
BACKGROUND Our goal is to develop a vascular targeting treatment for brain arteriovenous malformations (AVMs). Externalized phosphatidylserine has been established as a potential biomarker on the endothelium of irradiated AVM blood vessels. We hypothesize that phosphatidylserine could be selectively targeted after AVM radiosurgery with a ligand-directed vascular targeting agent to achieve localized thrombosis and rapid occlusion of pathological AVM vessels. OBJECTIVE The study aim was to establish an in vitro parallel-plate flow chamber to test the efficacy of a pro-thrombotic conjugate targeting phosphatidylserine. METHODS Conjugate was prepared by Lys-Lys cross-linking of thrombin with the phosphatidylserine-targeting ligand, annexin V. Cerebral microvascular endothelial cells were irradiated (5, 15, and 25 Gy) and after 1 or 3 days assembled in a parallel-plate flow chamber containing whole human blood and conjugate (1.25 or 2.5 μg/mL). Confocal microscopy was used to assess thrombus formation after flow via binding and aggregation of fluorescently-labelled platelets and fibrinogen. RESULTS AND CONCLUSIONS The annexin V-thrombin conjugate induced rapid thrombosis (fibrin deposition) on irradiated endothelial cells under shear stress in the parallel-plate flow device. Unconjugated, non-targeting thrombin did not induce fibrin deposition. A synergistic interaction between radiation and conjugate dose was observed. Thrombosis was greatest at the highest combined doses of radiation (25 Gy) and conjugate (2.5 μg/mL). The parallel-plate flow system provides a rapid method to pre-test pro-thrombotic vascular targeting agents. These findings validate the translation of the annexin V-thrombin conjugate to pre-clinical studies.
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Affiliation(s)
- S Subramanian
- Department of Clinical Medicine, Macquarie University, Sydney 2109, Australia
| | - S O Ugoya
- Department of Clinical Medicine, Macquarie University, Sydney 2109, Australia
| | - Z Zhao
- Department of Clinical Medicine, Macquarie University, Sydney 2109, Australia
| | - L S McRobb
- Department of Clinical Medicine, Macquarie University, Sydney 2109, Australia
| | - G E Grau
- Department of Pathology, University of Sydney, Sydney 2050, Australia
| | - V Combes
- University of Technology, School of Life Sciences, Sydney 2007, Australia
| | - D W Inglis
- School of Engineering, Macquarie University, Sydney 2109, Australia
| | - A J Gauden
- Department of Clinical Medicine, Macquarie University, Sydney 2109, Australia
| | - V S Lee
- Department of Clinical Medicine, Macquarie University, Sydney 2109, Australia
| | - V Moutrie
- Genesis Cancer Care, Macquarie University Hospital, Sydney 2109, Australia
| | - E D Santos
- Genesis Cancer Care, Macquarie University Hospital, Sydney 2109, Australia
| | - M A Stoodley
- Department of Clinical Medicine, Macquarie University, Sydney 2109, Australia.
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Abstract
Bio-imaging is a key technique in tracking and monitoring important biological processes and fundamental biomolecular interactions, however the interference of background autofluorescence with targeted fluorophores is problematic for many bio-imaging applications. This study reports on two novel methods for reducing interference with cellular autofluorescence for bio-imaging. The first method uses fluorescent nanodiamonds (FNDs), containing nitrogen vacancy centers. FNDs emit at near-infrared wavelengths typically higher than most cellular autofluorescence; and when appropriately functionalized, can be used for background-free imaging of targeted biomolecules. The second method uses europium-chelating tags with long fluorescence lifetimes. These europium-chelating tags enhance background-free imaging due to the short fluorescent lifetimes of cellular autofluorescence. In this study, we used both methods to target E-selectin, a transmembrane glycoprotein that is activated by inflammation, to demonstrate background-free fluorescent staining in fixed endothelial cells. Our findings indicate that both FND and Europium based staining can improve fluorescent bio-imaging capabilities by reducing competition with cellular autofluorescence. 30 nm nanodiamonds coated with the E-selectin antibody was found to enable the most sensitive detective of E-selectin in inflamed cells, with a 40-fold increase in intensity detected.
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Ionizing radiation reduces ADAM10 expression in brain microvascular endothelial cells undergoing stress-induced senescence. Aging (Albany NY) 2018; 9:1248-1268. [PMID: 28437250 PMCID: PMC5425125 DOI: 10.18632/aging.101225] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Accepted: 04/10/2017] [Indexed: 12/15/2022]
Abstract
Cellular senescence is associated with aging and is considered a potential contributor to age-associated neurodegenerative disease. Exposure to ionizing radiation increases the risk of developing premature neurovascular degeneration and dementia but also induces premature senescence. As cells of the cerebrovascular endothelium are particularly susceptible to radiation and play an important role in brain homeostasis, we investigated radiation-induced senescence in brain microvascular endothelial cells (EC). Using biotinylation to label surface proteins, streptavidin enrichment and proteomic analysis, we analyzed the surface proteome of stress-induced senescent EC in culture. An array of both recognized and novel senescence-associated proteins were identified. Most notably, we identified and validated the novel radiation-stimulated down-regulation of the protease, a disintegrin and metalloprotease 10 (ADAM10). ADAM10 is an important modulator of amyloid beta protein production, accumulation of which is central to the pathologies of Alzheimer's disease and cerebral amyloid angiopathy. Concurrently, we identified and validated increased surface expression of ADAM10 proteolytic targets with roles in neural proliferation and survival, inflammation and immune activation (L1CAM, NEO1, NEST, TLR2, DDX58). ADAM10 may be a key molecule linking radiation, senescence and endothelial dysfunction with increased risk of premature neurodegenerative diseases normally associated with aging.
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12
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Raoufi-Rad N, McRobb LS, Lee VS, Bervini D, Grace M, Ukath J, Mchattan J, Sreenivasan VKA, Duong TTH, Zhao Z, Stoodley MA. In vivo imaging of endothelial cell adhesion molecule expression after radiosurgery in an animal model of arteriovenous malformation. PLoS One 2017; 12:e0185393. [PMID: 28949989 PMCID: PMC5614630 DOI: 10.1371/journal.pone.0185393] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 09/12/2017] [Indexed: 12/18/2022] Open
Abstract
Focussed radiosurgery may provide a means of inducing molecular changes on the luminal surface of diseased endothelium to allow targeted delivery of novel therapeutic compounds. We investigated the potential of ionizing radiation to induce surface expression of intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) on endothelial cells (EC) in vitro and in vivo, to assess their suitability as vascular targets in irradiated arteriovenous malformations (AVMs). Cultured brain microvascular EC were irradiated by linear accelerator at single doses of 0, 5, 15 or 25 Gy and expression of ICAM-1 and VCAM-1 measured by qRT-PCR, Western, ELISA and immunocytochemistry. In vivo, near-infrared (NIR) fluorescence optical imaging using Xenolight 750-conjugated ICAM-1 or VCAM-1 antibodies examined luminal biodistribution over 84 days in a rat AVM model after Gamma Knife surgery at a single 15 Gy dose. ICAM-1 and VCAM-1 were minimally expressed on untreated EC in vitro. Doses of 15 and 25 Gy stimulated expression equally; 5 Gy was not different from the unirradiated. In vivo, normal vessels did not bind or retain the fluorescent probes, however binding was significant in AVM vessels. No additive increases in probe binding were found in response to radiosurgery at a dose of 15 Gy. In summary, radiation induces adhesion molecule expression in vitro but elevated baseline levels in AVM vessels precludes further induction in vivo. These molecules may be suitable targets in irradiated vessels without hemodynamic derangement, but not AVMs. These findings demonstrate the importance of using flow-modulated, pre-clinical animal models for validating candidate proteins for vascular targeting in irradiated AVMs.
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Affiliation(s)
- Newsha Raoufi-Rad
- Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Lucinda S. McRobb
- Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Vivienne S. Lee
- Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - David Bervini
- Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia
- Neurosurgery Department, Inselspital, University of Bern, Bern, Switzerland
| | - Michael Grace
- Genesis Cancer Care, Macquarie University Hospital, Sydney, New South Wales, Australia
| | - Jaysree Ukath
- Genesis Cancer Care, Macquarie University Hospital, Sydney, New South Wales, Australia
| | - Joshua Mchattan
- Carestream Molecular Imaging, Sydney, New South Wales, Australia
| | - Varun K. A. Sreenivasan
- Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia
- Department of Physics and Astronomy, Macquarie University, Sydney, New South Wales, Australia
| | - T. T. Hong Duong
- Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Zhenjun Zhao
- Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Marcus A. Stoodley
- Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia
- * E-mail:
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McRobb LS, Lee VS, Simonian M, Zhao Z, Thomas SG, Wiedmann M, Raj JVA, Grace M, Moutrie V, McKay MJ, Molloy MP, Stoodley MA. Radiosurgery Alters the Endothelial Surface Proteome: Externalized Intracellular Molecules as Potential Vascular Targets in Irradiated Brain Arteriovenous Malformations. Radiat Res 2017; 187:66-78. [PMID: 28054837 DOI: 10.1667/rr14518.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Stereotactic radiosurgery (SRS) is an established treatment for brain arteriovenous malformations (AVMs) that drives blood vessel closure through cellular proliferation, thrombosis and fibrosis, but is limited by a delay to occlusion of 2-3 years and a maximum treatable size of 3 cm. In this current study we used SRS as a priming tool to elicit novel protein expression on the endothelium of irradiated AVM vessels, and these proteins were then targeted with prothrombotic conjugates to induce rapid thrombosis and vessel closure. SRS-induced protein changes on the endothelium in an animal model of AVM were examined using in vivo biotin labeling of surface-accessible proteins and comparative proteomics. LC-MS/MS using SWATH acquisition label-free mass spectrometry identified 280 proteins in biotin-enriched fractions. The abundance of 56 proteins increased after irradiation of the rat arteriovenous fistula (20 Gy, ≥1.5-fold). A large proportion of intracellular proteins were present in this subset: 29 mitochondrial and 9 cytoskeletal. Three of these proteins were chosen for further validation based on previously published evidence for surface localization and a role in autoimmune stimulation: cardiac troponin I (TNNI3); manganese superoxide dismutase (SOD2); and the E2 subunit of the pyruvate dehydrogenase complex (PDCE2). Immunostaining of AVM vessels confirmed an increase in abundance of PDCE2 across the vessel wall, but not a measurable increase in TNNI3 or SOD2. All three proteins co-localized with the endothelium after irradiation, however, more detailed subcellular distribution could not be accurately established. In vitro, radiation-stimulated surface translocation of all three proteins was confirmed in nonpermeabilized brain endothelial cells using immunocytochemistry. Total protein abundance increased modestly after irradiation for PDCE2 and SOD2 but decreased for TNNI3, suggesting that radiation primarily affects subcellular distribution rather than protein levels. The novel identification of these proteins as surface exposed in response to radiation raises important questions about their potential role in radiation-induced inflammation, fibrosis and autoimmunity, but may also provide unique candidates for vascular targeting in brain AVMs and other vascular tissues.
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Affiliation(s)
- Lucinda S McRobb
- a Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Vivienne S Lee
- a Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Margaret Simonian
- a Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia.,c Department of Biological Chemistry, David Geffen School of Medicine, University of California Los Angeles (UCLA), Los Angeles, California
| | - Zhenjun Zhao
- a Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Santhosh George Thomas
- a Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Markus Wiedmann
- a Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Jude V Amal Raj
- a Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Michael Grace
- d Genesis Cancer Care, Macquarie University Hospital, Sydney, New South Wales, Australia
| | - Vaughan Moutrie
- d Genesis Cancer Care, Macquarie University Hospital, Sydney, New South Wales, Australia
| | - Matthew J McKay
- b Australian Proteome Analysis Facility, Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Mark P Molloy
- b Australian Proteome Analysis Facility, Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Marcus A Stoodley
- a Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia
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Animal Models in Studying Cerebral Arteriovenous Malformation. BIOMED RESEARCH INTERNATIONAL 2015; 2015:178407. [PMID: 26649296 PMCID: PMC4663287 DOI: 10.1155/2015/178407] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 10/11/2015] [Accepted: 10/25/2015] [Indexed: 12/13/2022]
Abstract
Brain arteriovenous malformation (AVM) is an important cause of hemorrhagic stroke. The etiology is largely unknown and the therapeutics are controversial. A review of AVM-associated animal models may be helpful in order to understand the up-to-date knowledge and promote further research about the disease. We searched PubMed till December 31, 2014, with the term “arteriovenous malformation,” limiting results to animals and English language. Publications that described creations of AVM animal models or investigated AVM-related mechanisms and treatments using these models were reviewed. More than 100 articles fulfilling our inclusion criteria were identified, and from them eight different types of the original models were summarized. The backgrounds and procedures of these models, their applications, and research findings were demonstrated. Animal models are useful in studying the pathogenesis of AVM formation, growth, and rupture, as well as in developing and testing new treatments. Creations of preferable models are expected.
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Raj JA, Stoodley M. Experimental Animal Models of Arteriovenous Malformation: A Review. Vet Sci 2015; 2:97-110. [PMID: 29061934 PMCID: PMC5644622 DOI: 10.3390/vetsci2020097] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 06/01/2015] [Accepted: 06/10/2015] [Indexed: 12/17/2022] Open
Abstract
Arteriovenous malformations (AVMs) are congenital lesions that cause brain haemorrhage in children and young adults. Current treatment modalities include surgery, radiosurgery and embolization. These treatments are generally effective only for small AVMs. Over one third of AVMs cannot be treated safely and effectively with existing options. Several animal models have been developed with the aims of understanding AVM pathophysiology and improving treatment. No animal model perfectly mimics a human AVM. Each model has limitations and advantages. Models contribute to the understanding of AVMs and hopefully to the development of improved therapies. This paper reviews animal models of AVMs and their advantages and disadvantages.
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Affiliation(s)
- Jude Amal Raj
- The Australian School of Advanced Medicine, Macquarie University, NSW 2109, Australia.
| | - Marcus Stoodley
- The Australian School of Advanced Medicine, Macquarie University, NSW 2109, Australia.
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16
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Kashba SR, Patel NJ, Grace M, Lee VS, Raoufi-Rad N, Raj JVA, Duong TTH, Stoodley M. Angiographic, hemodynamic, and histological changes in an animal model of brain arteriovenous malformations treated with Gamma Knife radiosurgery. J Neurosurg 2015; 123:954-60. [PMID: 25884263 DOI: 10.3171/2014.10.jns1435] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Brain arteriovenous malformations (AVMs) are a major cause of stroke. Many AVMs are effectively obliterated by stereotactic radiosurgery, but such treatment for lesions larger than 3 cm is not as effective. Understanding the responses to radiosurgery may lead to new biological enhancements to this treatment modality. The aim of the present study was to investigate the hemodynamic, morphological, and histological effects of Gamma Knife surgery (GKS) in an animal model of brain AVM. METHODS An arteriovenous fistula was created by anastomosing the left external jugular vein to the side of the common carotid artery in 64 male Sprague-Dawley rats (weight 345 ± 8.8 g). Six weeks after AVM creation, 32 rats were treated with a single dose of GKS (20 Gy); 32 animals received sham radiation. Eight irradiated and 8 control animals were studied at each specified time point (1, 3, 6, and 12 weeks) for hemodynamic, morphological, and histological characterization. RESULTS Two AVMs showed partial angiographic obliteration at 6 weeks. Angiography revealed complete obliteration in 3 irradiated rats at 12 weeks. Blood flow in the ipsilateral proximal carotid artery (p < 0.001) and arterialized jugular vein (p < 0.05) was significantly lower in the irradiated group than in the control group. The arterialized vein's external diameter was significantly smaller in GKS-treated animals at 6 (p < 0.05) and 12 (p < 0.001) weeks. Histological changes included subendothelial cellular proliferation and luminal narrowing in GKS-treated animals. Neither luminal obliteration nor thrombus formation was identified at any of the time points in either irradiated or nonirradiated animals. CONCLUSIONS GKS produced morphological, angiographic, and histological changes in the model of AVM as early as 6 weeks after treatment. These results support the use of this model for studying methods to enhance radiation response in AVMs.
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Affiliation(s)
- Saleh R Kashba
- Australian School of Advanced Medicine, Macquarie University; and
| | - Nirav J Patel
- Australian School of Advanced Medicine, Macquarie University; and
| | - Michael Grace
- Genesis Cancer Care, Macquarie University Hospital, Sydney, New South Wales, Australia
| | - Vivienne S Lee
- Australian School of Advanced Medicine, Macquarie University; and
| | | | - Jude V Amal Raj
- Australian School of Advanced Medicine, Macquarie University; and
| | | | - Marcus Stoodley
- Australian School of Advanced Medicine, Macquarie University; and
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Tu J, Li Y, Hu Z, Chen Z. Radiosurgery inhibition of the Notch signaling pathway in a rat model of arteriovenous malformations. J Neurosurg 2014; 120:1385-96. [DOI: 10.3171/2013.12.jns131595] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Object
Notch signaling has been suggested to promote the development and maintenance of arteriovenous malformations (AVMs), but whether radiosurgery inhibits Notch signaling pathways in AVMs is unknown. The aim of this study was to examine molecular changes of Notch signaling pathways following radiosurgery and to explore mechanisms of radiosurgical obliteration of “nidus” vessels in a rat model of AVMs.
Methods
One hundred eleven rats received common carotid artery–to–external jugular vein anastomosis to form an arteriovenous fistula (AVF) model. Six weeks postoperatively, dilated small vessels and capillaries formed a nidus. The rats with AVFs received 25-Gy radiosurgery. The expression of Notch1 and Notch4 receptors and their ligands, Delta-like1 and Delta-like4, Jagged1, Notch downstream gene target HES1, and an apoptotic marker caspase-3 in nidus vessels in the AVF rats was examined immunohistochemically and was quantified using LAS-AF software at 7 time points over a period of 42 days postradiosurgery. The interaction events between Notch1 receptor and Jagged1, as well as Notch4 receptor and Jagged1, were quantified in nidus vessels in the AVF rats using proximity ligation assay at different time points over 42 days postradiosurgery.
Results
The expression of Notch1 and Notch4 receptors, Delta-like1, Delta-like4, Jagged1, and HES1 was observed in nidus vessels in the AVF rats pre- and postradiosurgery. Radiosurgery enhanced apoptotic activity (p < 0.05) and inhibited the expression of Notch1 and Notch4 receptors and Jagged1 in the endothelial cells of nidus vessels in the AVF rats at 1, 2, 3, 7, 21, 28, and 42 days postradiosurgery (p < 0.05). Radiosurgery suppressed the interaction events between Notch1 receptor and Jagged1 (p < 0.001) as well as Notch4 receptor and Jagged1 (p < 0.001) in the endothelial cells of nidus vessels in the AVF rats over a period of 42 days postradiosurgery. Radiosurgery induced thrombotic occlusion of nidus vessels in the AVF rats. There was a positive correlation between the percentage of fully obliterated nidus vessels and time after radiosurgery (r = 0.9324, p < 0.001).
Conclusions
Radiosurgery inhibits endothelial Notch1 and Notch4 signaling pathways in nidus vessels while inducing thrombotic occlusion of nidus vessels in a rat model of AVMs. The underlying mechanisms of radiosurgery-induced AVM shrinkage could be a combination of suppressing Notch receptor signaling in blood vessel endothelial cells, leading to a reduction in nidus vessel size and thrombotic occlusion of nidus vessels.
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Affiliation(s)
- Jian Tu
- 1Australian School of Advanced Medicine, Macquarie University, Sydney, New South Wales, Australia
| | - Yang Li
- 1Australian School of Advanced Medicine, Macquarie University, Sydney, New South Wales, Australia
| | - Zhiqiang Hu
- 2Department of Neurosurgery, the 9th Medical Clinical College of Beijing University; and
| | - Zhongbin Chen
- 3Department of Electromagnetic and Laser Biology, Beijing Institute of Radiation Medicine, Beijing, China
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Notch1 and 4 signaling responds to an increasing vascular wall shear stress in a rat model of arteriovenous malformations. BIOMED RESEARCH INTERNATIONAL 2014; 2014:368082. [PMID: 24563863 PMCID: PMC3915856 DOI: 10.1155/2014/368082] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 12/11/2013] [Indexed: 11/17/2022]
Abstract
Notch signaling is suggested to promote the development and maintenance of cerebral arteriovenous malformations (AVMs), and an increasing wall shear stress (WSS) contributes to AVM rupture. Little is known about whether WSS impacts Notch signaling, which is important for understanding the angiogenesis of AVMs. WSS was measured in arteriovenous fistulas (AVF) surgically created in 96 rats at different time points over a period of 84 days. The expression of Notch receptors 1 and 4 and their ligands, Delta1 and 4, Jagged1, and Notch downstream gene target Hes1 was quantified in “nidus” vessels. The interaction events between Notch receptors and their ligands were quantified using proximity ligation assay. There was a positive correlation between WSS and time (r = 0.97; P < 0.001). The expression of Notch receptors and their ligands was upregulated following AVF formation. There was a positive correlation between time and the number of interactions between Notch receptors and their ligands aftre AVF formation (r = 0.62, P < 0.05) and a positive correlation between WSS and the number of interactions between Notch receptors and their ligands (r = 0.87, P < 0.005). In conclusion, an increasing WSS may contribute to the angiogenesis of AVMs by activation of Notch signaling.
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Endothelial gene expression and molecular changes in response to radiosurgery in in vitro and in vivo models of cerebral arteriovenous malformations. BIOMED RESEARCH INTERNATIONAL 2013; 2013:408253. [PMID: 24199192 PMCID: PMC3807843 DOI: 10.1155/2013/408253] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 08/31/2013] [Indexed: 01/30/2023]
Abstract
Radiosurgery for cerebral arteriovenous malformations (AVMs) is limited to 2-year latency. There is no early marker to monitor whether the lesion is responsive to radiosurgery. In this study, we examined endothelial gene expression and molecular changes in response to radiosurgery. Gene expression of E- and P-selectin, ICAM-1, PECAM-1, VCAM-1, tissue factor, and vWF in human cerebral microvascular endothelial cells was quantified by RT-qPCR at different radiation doses and time points. Soluble E- and P-selectin, ICAM-1, VCAM-1, and tissue factor in an animal model of AVMs were quantified by ELISA at different time after radiosurgery. We found that gene expression of E- and P-selectin, ICAM-1, PECAM-1, and VCAM-1 was upregulated by radiation in a dose-dependent manner (P < .05). Gene expression of E- and P-selectin and ICAM-1 was more sensitive to irradiation than that of PECAM-1 and VCAM-1. Radiosurgery induced gene expression of P-selectin, ICAM-1, PECAM-1, and VCAM-1 was linearly correlated with time (P < .05). Radiosurgery induced elevation of soluble E- and P-selectin, ICAM-1, VCAM-1, and tissue factor in a rat model of AVMs (P < .05). Thus, a combination of these molecules measured at different time points may serve as an early predictor of responsiveness of AVMs to radiosurgery.
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