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Tissue oxygenation stabilizes neovessels and mitigates hemorrhages in human atherosclerosis-induced angiogenesis. Angiogenesis 2023; 26:63-76. [PMID: 35947328 DOI: 10.1007/s10456-022-09851-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 07/21/2022] [Indexed: 11/01/2022]
Abstract
Progression of atherosclerosis is associated with a maladaptive form of angiogenesis which contributes to intraplaque hemorrhage and plaque disruption. Hypoxia has been implicated in mechanisms of angiogenic neovessel fragility and atherosclerotic plaque destabilization. We used ex vivo and in vivo models to characterize the effect of oxygen (O2) on the formation, stability and tendency to bleed of human plaque-induced neovessels. Plaque explants potently stimulated the ex vivo angiogenic response of rat aortic rings at atmospheric O2 levels. Severe hypoxia (1% O2) inhibited plaque-induced angiogenesis and pericyte recruitment causing neovessel breakdown, whereas increasing O2 levels dose dependently enhanced pericyte numbers and neovessel stability. Plaque fragments implanted subcutaneously with or without aortic rings in SCID mice stimulated the host angiogenic response with plaques causing minimal or no hemorrhages and plaques co-implanted with aortic rings causing marked hemorrhages. Plaque/aortic ring-induced hemorrhages were reduced in mice exposed to moderate hyperoxia (50% O2). Hyperoxia downregulated expression of the hypoxia-sensitive genes Ca9, Ca12 and VegfA and increased influx into implants of mesenchymal cells reactive for the pericyte marker NG2. In both ex vivo and in vivo models, O2 promoted expression of vasostabilizing genes required for pericyte recruitment (Angpt1, Pdgfb), basement membrane assembly (Col4A1), and tight junction formation (Cldn5 and/or Ocln). Our results suggest that formation of neovessels that are stable, pericyte-coated, and resistant to bleeding requires adequate tissue oxygenation. Understanding the mechanisms by which O2 stabilizes neovessels and mitigates neovessel bleeding may lead to new therapies for the prevention of atherosclerosis complications.
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Phillippi JA. On vasa vasorum: A history of advances in understanding the vessels of vessels. SCIENCE ADVANCES 2022; 8:eabl6364. [PMID: 35442731 PMCID: PMC9020663 DOI: 10.1126/sciadv.abl6364] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 03/01/2022] [Indexed: 05/09/2023]
Abstract
The vasa vasorum are a vital microvascular network supporting the outer wall of larger blood vessels. Although these dynamic microvessels have been studied for centuries, the importance and impact of their functions in vascular health and disease are not yet fully realized. There is now rich knowledge regarding what local progenitor cell populations comprise and cohabitate with the vasa vasorum and how they might contribute to physiological and pathological changes in the network or its expansion via angiogenesis or vasculogenesis. Evidence of whether vasa vasorum remodeling incites or governs disease progression or is a consequence of cardiovascular pathologies remains limited. Recent advances in vasa vasorum imaging for understanding cardiovascular disease severity and pathophysiology open the door for theranostic opportunities. Approaches that strive to control angiogenesis and vasculogenesis potentiate mitigation of vasa vasorum-mediated contributions to cardiovascular diseases and emerging diseases involving the microcirculation.
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Affiliation(s)
- Julie A. Phillippi
- Department of Cardiothoracic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Department of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, PA, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
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Zhao X, Wei X, Wang X, Qi G. Long non‑coding RNA NORAD regulates angiogenesis of human umbilical vein endothelial cells via miR‑590‑3p under hypoxic conditions. Mol Med Rep 2020; 21:2560-2570. [PMID: 32323787 PMCID: PMC7185274 DOI: 10.3892/mmr.2020.11064] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 03/13/2020] [Indexed: 12/19/2022] Open
Abstract
Dysregulation of angiogenesis can be caused by hypoxia, which may result in severe diseases of the heart, including coronary artery disease. Hypoxia‑inducible factor 1 (HIF‑1) modulates angiogenesis via the regulation of several angiogenic factors. However, the underlying mechanism of hypoxia‑induced angiogenesis remains unknown. In the present study, it was hypothesized that long non‑coding RNA (lncRNA) non‑coding RNA activated by DNA damage (NORAD) may serve a role in the process of angiogenesis via the regulation of microRNA(miR)‑590‑3p under hypoxic conditions. The effect of NORAD and miR‑590‑3p on cell viability and properties associated with angiogenesis, including cell migration and tube formation in human umbilical vein endothelial cells (HUVECs) under hypoxic conditions, were assessed. Potential downstream angiogenic factors of miR‑590‑3p were also determined by molecular experiments. It was identified that NORAD expression was upregulated and miR‑590‑3p expression was downregulated in hypoxia‑exposed HUVECs, and also in myocardial infarction (MI) left ventricle tissues in mice. Moreover, downregulation of NORAD expression resulted in decreased cell viability and angiogenic capacity, but further knocking down miR‑590‑3p expression reversed these alterations, resulting in increased cell migration and tube formation in HUVECs under hypoxic conditions for 24 h. It was demonstrated that NORAD overexpression also increased cell vitality and tube‑formation capacity. Furthermore, NORAD was identified to bind with miR‑590‑3p directly, and miR‑590‑3p was shown to target certain proangiogenic agents, such as vascular endothelial growth factor (VEGF)A, fibroblast growth factor (FGF)1 and FGF2 directly. Therefore, the present results suggested that lncRNA NORAD may bind with miR‑590‑3p to regulate the angiogenic ability of HUVECs via the regulation of several downstream proangiogenic factors under hypoxia. Thus, the lncRNA NORAD/miR‑590‑3p axis may be a novel regulatory pathway in the angiogenic mechanisms in HUVECs, which highlights a potentially novel perspective for treating ischemia/hypoxia‑induced angiogenic diseases.
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Affiliation(s)
- Xiaoxue Zhao
- Department of Geriatrics, The First Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Xiufang Wei
- Department of Geriatrics, The First Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Xueying Wang
- Department of Geriatrics, The First Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Guoxian Qi
- Department of Geriatrics, The First Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
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Lu L, Chen H, Hao D, Zhang X, Wang F. The functions and applications of A7R in anti-angiogenic therapy, imaging and drug delivery systems. Asian J Pharm Sci 2019; 14:595-608. [PMID: 32104486 PMCID: PMC7032227 DOI: 10.1016/j.ajps.2019.04.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Revised: 03/31/2019] [Accepted: 04/24/2019] [Indexed: 12/26/2022] Open
Abstract
Vascular endothelial growth factor receptor 2 (VEGFR-2) and neuropilin-1 (NRP-1) are two prominent antiangiogenic targets. They are highly expressed on vascular endothelial cells and some tumor cells. Therefore, targeting VEGFR-2 and NRP-1 may be a potential antiangiogenic and antitumor strategy. A7R, a peptide with sequence of Ala-Thr-Trp-Leu-Pro-Pro-Arg that was found by phage display of peptide libraries, can preferentially target VEGFR-2 and NRP-1 and destroy the binding between vascular endothelial growth factor 165 (VEGF165) and VEGFR-2 or NRP-1. This peptide is a new potent inhibitor of tumor angiogenesis and a targeting ligand for cancer therapy. This review describes the discovery, function and mechanism of the action of A7R, and further introduces the applications of A7R in antitumor angiogenic treatments, tumor angiogenesis imaging and targeted drug delivery systems. In this review, strategies to deliver different drugs by A7R-modified liposomes and nanoparticles are highlighted. A7R, a new dual targeting ligand of VEGFR-2 and NRP-1, is expected to have efficient therapeutic or targeting roles in tumor drug delivery.
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Affiliation(s)
- Lu Lu
- Key Laboratory of Chemical Biology (Ministry of Education), Institute of Biochemical and Biotechnological Drug, School of Pharmaceutical Sciences, Shandong University, Jinan 250012, China
| | - Hongyuan Chen
- Department of General Surgery, Shandong University Affiliated Shandong Provincial Hospital, Jinan 250021, China
| | - Dake Hao
- Department of Surgery, UC Davis Health Medical Center, Sacramento 95817, USA
| | - Xinke Zhang
- Key Laboratory of Chemical Biology (Ministry of Education), Department of Pharmacology, School of Pharmaceutical Sciences, Shandong University, Jinan 250012, China
| | - Fengshan Wang
- Key Laboratory of Chemical Biology (Ministry of Education), Institute of Biochemical and Biotechnological Drug, School of Pharmaceutical Sciences, Shandong University, Jinan 250012, China
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Jalkanen J, Hautero O, Maksimow M, Jalkanen S, Hakovirta H. Correlation between increasing tissue ischemia and circulating levels of angiogenic growth factors in peripheral artery disease. Cytokine 2018; 110:24-28. [PMID: 29689451 DOI: 10.1016/j.cyto.2018.04.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Revised: 03/08/2018] [Accepted: 04/09/2018] [Indexed: 10/17/2022]
Abstract
INTRODUCTION The aim of the present study was to assess the circulating levels of vascular endothelial growth factor (VEGF) and other suggested therapeutic growth factors with the degree of ischemia in patients with different clinical manifestations of peripheral arterial disease (PAD) according to the Rutherford grades. METHODS The study cohort consists of 226 consecutive patients admitted to a Department of Vascular Surgery for elective invasive procedures. PAD patients were grouped according to the Rutherford grades after a clinical assessment. Ankle-brachial pressure indices (ABI) and absolute toe pressure (TP) values were measured. Serum levels of circulating VEGF, hepatocyte growth factor (HGF), basic fibroblast growth factor (bFGF), and platelet derived growth factor (PDGF) were measured from serum and analysed against Rutherford grades and peripheral hemodynamic measurements. RESULTS The levels of VEGF (P = 0.009) and HGF (P < 0.001) increased significantly as the ischaemic burden became more severe according to the Rutherford grades. PDGF behaved in opposite manner and declined along increasing Rutherford grades (P = 0.004). A significant, inverse correlations between Rutherford grades was detected as follows; VEGF (Pearson's correlation = 0.183, P = 0.004), HGF (Pearson's correlation = 0.253, P < 0.001), bFGF (Pearson's correlation = 0.169, P = 0.008) and PDGF (Pearson's correlation = 0.296, P < 0.001). In addition, VEGF had a clear direct negative correlation with ABI (Pearson's correlation -0.19, P = 0.009) and TP (Pearson's correlation -0.20, P = 0.005) measurements. CONCLUSIONS Our present observations show that the circulating levels of VEGF and other suggested therapeutic growth factors are significantly increased along with increasing ischemia. These findings present a new perspective to anticipated positive effects of gene therapies utilizing VEGF, HGF, and bFGF, because the levels of these growth factors are endogenously high in end-stage PAD.
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Affiliation(s)
- Juho Jalkanen
- Department of Vascular Surgery, Turku University and Turku University Hospital, Turku, Finland.
| | - Olli Hautero
- Department of Vascular Surgery, Turku University and Turku University Hospital, Turku, Finland
| | - Mikael Maksimow
- Medicity Research Laboratory, Department of Microbiology and Immunology, University of Turku, Turku, Finland
| | - Sirpa Jalkanen
- Medicity Research Laboratory, Department of Microbiology and Immunology, University of Turku, Turku, Finland
| | - Harri Hakovirta
- Department of Vascular Surgery, Turku University and Turku University Hospital, Turku, Finland.
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Beltramo E, Arroba AI, Mazzeo A, Valverde AM, Porta M. Imbalance between pro-apoptotic and pro-survival factors in human retinal pericytes in diabetic-like conditions. Acta Ophthalmol 2018; 96:e19-e26. [PMID: 28127871 DOI: 10.1111/aos.13377] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 12/03/2016] [Indexed: 12/11/2022]
Abstract
PURPOSE Loss of pericytes is one the key events in the pathogenesis of diabetic retinopathy. We have previously demonstrated that human retinal pericytes (HRP) are more vulnerable to intermittent than stable high glucose concentrations, with an increase in apoptosis. Our aim was to explore the expression of molecules involved in pro-apoptotic and survival pathways in pericytes cultured in stable/intermittent high glucose and/or hypoxia, to clarify the mechanisms of action of these diabetic-like stressing stimuli. METHODS Human retinal pericytes (HRP) were exposed intermittently at 48-hr intervals to high/physiological glucose for 8 days (intHG) and/or hypoxia over the last 48 hr. Control cells were kept in stable physiological and high glucose. Cell proliferation and apoptosis were assessed. The expression of pro-apoptotic and pro-survival molecules was evaluated by Western blotting. Caspase-8 translocation from the cytoplasm into the nucleus was checked by Western blotting of nuclear versus cytoplasmic fractions and immunofluorescence. RESULTS Hypoxia, alone and combined with intHG, increased HRP apoptosis and decreased proliferation. Pro-apoptotic molecules increased in HRP cultured in these conditions, while some survival markers decreased. Conversely, in stable HG, pro-apoptotic molecules were stable or even decreased, and survival factors increased. Translocation of caspase-8 from cytoplasm into nucleus indicates a primary role for this molecule in inducing apoptosis. CONCLUSION Diabetic-like conditions are able to stimulate pericyte apoptosis through activation of pro-apoptotic molecules, leading to an imbalance between pro-apoptotic and survival signalling pathways, with caspase-8 playing a pivotal role. Our identification of such intermediates could help finding new therapeutic approaches for the prevention of diabetic retinopathy.
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Affiliation(s)
- Elena Beltramo
- Department of Medical Sciences; University of Turin; Torino Italy
| | - Ana I. Arroba
- Institut of Biomedical Research Alberto Sols; Madrid Spain
- Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Disorders (CIBERdem); Madrid Spain
| | - Aurora Mazzeo
- Department of Medical Sciences; University of Turin; Torino Italy
| | - Angela M. Valverde
- Institut of Biomedical Research Alberto Sols; Madrid Spain
- Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Disorders (CIBERdem); Madrid Spain
| | - Massimo Porta
- Department of Medical Sciences; University of Turin; Torino Italy
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Hypoxia induces the dysfunction of human endothelial colony-forming cells via HIF-1α signaling. Respir Physiol Neurobiol 2017; 247:87-95. [PMID: 28964937 DOI: 10.1016/j.resp.2017.09.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 08/29/2017] [Accepted: 09/22/2017] [Indexed: 12/15/2022]
Abstract
Endothelial injury is considered as a trigger of pulmonary vascular lesions in the pathogenesis of hypoxic pulmonary hypertension (HPH). Although endothelial colony-forming cells (ECFCs) have vascular regeneration potential to maintain endothelial integrity, hypoxia-induced precise alteration in ECFCs function remains controversial. This study investigated the impact of hypoxia on human ECFCs function in vitro and the underlying mechanism. We found that hypoxia inhibited ECFCs proliferation, migration and angiogenesis. Compared with no treatment, the expression of hypoxia inducible factor-1α (HIF-1α) in hypoxia-treated ECFCs was increased, with an up-regulation of p27 and a down-regulation of cyclin D1. The over-secreted vascular endothelial growth factor (VEGF) was detected, with the imbalanced expression of fetal liver kinase 1 (flk-1) and fms related tyrosine kinase 1 (flt-1). Hypoxia-induced changes in ECFCs could be reversed by HIF-1α inhibitor KC7F2. These data suggest that HIF-1α holds the key in regulating ECFCs function which may open a new perspective of ECFCs in HPH management.
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Mansurov N, Chen WCW, Awada H, Huard J, Wang Y, Saparov A. A controlled release system for simultaneous delivery of three human perivascular stem cell-derived factors for tissue repair and regeneration. J Tissue Eng Regen Med 2017; 12:e1164-e1172. [PMID: 28482145 DOI: 10.1002/term.2451] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 01/17/2017] [Accepted: 05/04/2017] [Indexed: 11/07/2022]
Abstract
Transplanted stem/progenitor cells improve tissue healing and regeneration anatomically and functionally, mostly due to their secreted trophic factors. However, harsh conditions at the site of injury, including hypoxia, oxidative and inflammatory stress, increased fibrosis and insufficient angiogenesis, and in some cases immunological response or incompatibility, are detrimental to stem cell survival. To overcome the complexity and deficiencies of stem cell therapy, the coacervate delivery platform is deemed promising because it offers controlled and sustained release using heparin to recapitulate the binding and stabilization of extracellular proteins by heparan sulphates in native tissues. Here we show that recombinant alternatives of three key factors [vascular endothelial growth factor (VEGF), monocyte chemoattractant protein-1 (MCP-1) and interleukin-6 (IL-6)], commonly produced by perivascular stem cells under various stress conditions, can be successfully incorporated into a heparin-based coacervate. We characterized the release profile of the triply incorporated factors from the complex coacervate. The coacervate-released factors were able to exert their desired biological activities in vitro: VEGF stimulated human umbilical vein endothelial cell proliferation, MCP-1 elevated macrophage migration and IL-6 increased IgM production by IL-6-dependent cell line. Thus, a controlled release system can be used for simultaneous delivery of three stem cell-derived factors and could be useful for tissue repair and regenerative medicine.
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Affiliation(s)
- Nurlan Mansurov
- Department of Biomedical Sciences, Nazarbayev University School of Medicine, Nazarbayev University, Astana, Kazakhstan
| | - William C W Chen
- Research Laboratory of Electronics and Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Hassan Awada
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.,McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Johnny Huard
- Department of Orthopedic Surgery and Center for Tissue Engineering and Aging Research, University of Texas Health Science Center at Houston, McGovern Medical School, Houston, TX, USA.,Center for Sports Regenerative Medicine, Steadman Philippon Research Institute, Vail, CO, USA
| | - Yadong Wang
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.,McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Arman Saparov
- Department of Biomedical Sciences, Nazarbayev University School of Medicine, Nazarbayev University, Astana, Kazakhstan
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Beltramo E, Lopatina T, Mazzeo A, Arroba AI, Valverde AM, Hernández C, Simó R, Porta M. Effects of the neuroprotective drugs somatostatin and brimonidine on retinal cell models of diabetic retinopathy. Acta Diabetol 2016; 53:957-964. [PMID: 27552833 DOI: 10.1007/s00592-016-0895-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 08/05/2016] [Indexed: 12/31/2022]
Abstract
AIMS Diabetic retinopathy is considered a microvascular disease, but recent evidence has underlined early involvement of the neuroretina with interactions between microvascular and neural alterations. Topical administration of somatostatin (SST), a neuroprotective molecule with antiangiogenic properties, prevents diabetes-induced retinal neurodegeneration in animals. The α2-adrenergic receptor agonist brimonidine (BRM) decreases vitreoretinal vascular endothelial growth factor and inhibits blood-retinal barrier breakdown in diabetic rats. However, SST and BRM effects on microvascular cells have not yet been studied. We investigated the behaviour of these drugs on the crosstalk between microvasculature and neuroretina. METHODS Expression of SST receptors 1-5 in human retinal pericytes (HRP) was checked. We subsequently evaluated the effects of diabetic-like conditions (high glucose and/or hypoxia) with/without SST/BRM on HRP survival. Endothelial cells (EC) and photoreceptors were maintained in the above conditions and their conditioned media (CM) used to culture HRP. Vice versa, HRP-CM was used on EC and photoreceptors. Survival parameters were assessed. RESULTS HRP express the SST receptor 1 (SSTR1). Glucose fluctuations mimicking those occurring in diabetic subjects are more damaging for pericytes and photoreceptors than stable high glucose and hypoxic conditions. SST/BRM added to HRP in diabetic-like conditions decrease EC apoptosis. However, neither SST nor BRM changed the response of pericytes and neuroretina-vascular crosstalk under diabetic-like conditions. CONCLUSIONS Retinal pericytes express SSTR1, indicating that they can be a target for SST. Exposure to SST/BRM had no adverse effects, direct or mediated by the neuroretina, suggesting that these molecules could be safely evaluated for the treatment of ocular diseases.
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Affiliation(s)
- Elena Beltramo
- Department of Medical Sciences, University of Turin, Corso AM Dogliotti 14, 10126, Turin, Italy.
| | - Tatiana Lopatina
- Department of Medical Sciences, University of Turin, Corso AM Dogliotti 14, 10126, Turin, Italy
| | - Aurora Mazzeo
- Department of Medical Sciences, University of Turin, Corso AM Dogliotti 14, 10126, Turin, Italy
| | - Ana I Arroba
- Alberto Sols Biomedical Research Institute (IIBm) (CSIC/UAM), C/Arturo Duperier 4, 28029, Madrid, Spain
- Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Disorders (CIBERdem), ISCIII, Instituto de Salud Carlos III, C/Monforte de Lemos 3-5, 28029, Madrid, Spain
| | - Angela M Valverde
- Alberto Sols Biomedical Research Institute (IIBm) (CSIC/UAM), C/Arturo Duperier 4, 28029, Madrid, Spain
- Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Disorders (CIBERdem), ISCIII, Instituto de Salud Carlos III, C/Monforte de Lemos 3-5, 28029, Madrid, Spain
| | - Cristina Hernández
- Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Disorders (CIBERdem), ISCIII, Instituto de Salud Carlos III, C/Monforte de Lemos 3-5, 28029, Madrid, Spain
- Diabetes and Metabolism Research Unit, Institut de Recerca Hospital Universitari Vall d'Hebron (VHIR), Pg. Vall d'Hebron 119-129, 08035, Barcelona, Spain
| | - Rafael Simó
- Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Disorders (CIBERdem), ISCIII, Instituto de Salud Carlos III, C/Monforte de Lemos 3-5, 28029, Madrid, Spain
- Diabetes and Metabolism Research Unit, Institut de Recerca Hospital Universitari Vall d'Hebron (VHIR), Pg. Vall d'Hebron 119-129, 08035, Barcelona, Spain
| | - Massimo Porta
- Department of Medical Sciences, University of Turin, Corso AM Dogliotti 14, 10126, Turin, Italy
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Identification of HIF-2α-regulated genes that play a role in human microvascular endothelial sprouting during prolonged hypoxia in vitro. Angiogenesis 2016; 20:39-54. [PMID: 27699500 PMCID: PMC5306362 DOI: 10.1007/s10456-016-9527-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 09/28/2016] [Indexed: 12/24/2022]
Abstract
During prolonged hypoxic conditions, endothelial cells change their gene expression to adjust to the low oxygen environment. This process is mainly regulated by the hypoxia-inducible factors, HIF-1α and HIF-2α. Although endothelial cells do not form sprouts during prolonged hypoxic culturing, silencing of HIF-2α partially restores sprout formation. The present study identifies novel HIF-2α-target genes that may regulate endothelial sprouting during prolonged hypoxia. The gene expression profile of primary human microvascular endothelial cells (hMVECs) that were cultured at 20 % oxygen was compared to hMVECs that were cultured at 1 % oxygen for 14 days by using genome-wide RNA-sequencing. The differentially regulated genes in hypoxia were compared to the genes that were differentially regulated upon silencing of HIF-2α in hypoxia. Surprisingly, KEGG pathway analysis showed that metabolic pathways were enriched within genes upregulated in response to hypoxia and enriched within genes downregulated upon HIF-2α silencing. Moreover, 51 HIF-2α-regulated genes were screened for their role in endothelial sprouting in hypoxia, of which four genes ARRDC3, MME, PPARG and RALGPS2 directly influenced endothelial sprouting during prolonged hypoxic culturing. The manipulation of specific downstream targets of HIF-2α provides a new, but to be further evaluated, perspective for restoring reduced neovascularization in several pathological conditions, such as diabetic ulcers or other chronic wounds, for improvement of vascularization of implanted tissue-engineered scaffolds.
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