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1.
Ther Adv Respir Dis ; 16: 17534666221096040, 2022.
Article in English | MEDLINE | ID: covidwho-1822140

ABSTRACT

PURPOSE: We aimed to better understand the pathophysiology of SARS-CoV-2 pneumonia in non-critically ill hospitalized patients secondarily presenting with clinical deterioration and increase in oxygen requirement without any identified worsening factors. METHODS: We consecutively enrolled patients without clinical or biological evidence for superinfection, without left ventricular dysfunction and for whom a pulmonary embolism was discarded by computed tomography (CT) pulmonary angiography. We investigated lung ventilation and perfusion (LVP) by LVP scintigraphy, and, 24 h later, left and right ventricular function by Tc-99m-labeled albumin-gated blood-pool scintigraphy with late (60 mn) tomographic albumin images on the lungs to evaluate lung albumin retention that could indicate microvascular injuries with secondary edema. RESULTS: We included 20 patients with confirmed SARS-CoV-2 pneumonia. All had CT evidence of organizing pneumonia and normal left ventricular ejection fraction. No patient demonstrated preserved ventilation with perfusion defect (mismatch), which may discard a distal lung thrombosis. Patterns of ventilation and perfusion were heterogeneous in seven patients (35%) with healthy lung segments presenting a relative paradoxical hypoperfusion and hypoventilation compared with segments with organizing pneumonia presenting a relative enhancement in perfusion and preserved ventilation. Lung albumin retention in area of organizing pneumonia was observed in 12 patients (60%), indicating microvascular injuries, increase in vessel permeability, and secondary edema. CONCLUSION: In hospitalized non-critically ill patients without evidence of superinfection, pulmonary embolism, or cardiac dysfunction, various types of damage may contribute to clinical deterioration including microvascular injuries and secondary edema, inconsistencies in lung segments vascularization suggesting a dysregulation of the balance in perfusion between segments affected by COVID-19 and others. SUMMARY STATEMENT: Microvascular injuries and dysregulation of the balance in perfusion between segments affected by COVID-19 and others are present in non-critically ill patients without other known aggravating factors. KEY RESULTS: In non-critically ill patients without evidence of superinfection, pulmonary embolism, macroscopic distal thrombosis or cardiac dysfunction, various types of damage may contribute to clinical deterioration including 1/ microvascular injuries and secondary edema, 2/ inconsistencies in lung segments vascularization with hypervascularization of consolidated segments contrasting with hypoperfusion of not affected segments, suggesting a dysregulation of the balance in perfusion between segments affected by COVID-19 and others.


Subject(s)
COVID-19 , Clinical Deterioration , Heart Diseases , Pulmonary Embolism , Superinfection , Albumins , Edema/diagnostic imaging , Edema/etiology , Humans , Lung/diagnostic imaging , Neovascularization, Pathologic , SARS-CoV-2 , Stroke Volume , Ventricular Function, Left
2.
Sci Rep ; 12(1): 4867, 2022 03 22.
Article in English | MEDLINE | ID: covidwho-1758369

ABSTRACT

Leucine-rich α-2-glycoprotein 1 (LRG1) is a secreted glycoprotein that under physiological conditions is produced predominantly by the liver. In disease, its local induction promotes pathogenic neovascularisation while its inhibition leads to reduced dysfunctional angiogenesis. Here we examine the role of interleukin-6 (IL-6) in defective angiogenesis mediated by LRG1. IL-6 treatment induced LRG1 expression in endothelial cells and ex vivo angiogenesis cultures and promoted vascular growth with reduced mural cell coverage. In Lrg1-/- explants, however, IL-6 failed to stimulate angiogenesis and vessels exhibited improved mural cell coverage. IL-6 activated LRG1 transcription through the phosphorylation and binding of STAT3 to a conserved consensus site in the LRG1 promoter, the deletion of which abolished activation. Blocking IL-6 signalling in human lung endothelial cells, using the anti-IL6 receptor antibody Tocilizumab, significantly reduced LRG1 expression. Our data demonstrate that IL-6, through STAT3 phosphorylation, activates LRG1 transcription resulting in vascular destabilisation. This observation is especially timely in light of the potential role of IL-6 in COVID-19 patients with severe pulmonary microvascular complications, where targeting IL-6 has been beneficial. However, our data suggest that a therapy directed towards blocking the downstream angiopathic effector molecule LRG1 may be of greater utility.


Subject(s)
Glycoproteins , Interleukin-6 , Neovascularization, Pathologic , STAT3 Transcription Factor , COVID-19 , Endothelial Cells/metabolism , Glycoproteins/metabolism , Humans , Interleukin-6/metabolism , Neovascularization, Pathologic/metabolism , STAT3 Transcription Factor/metabolism
3.
Front Immunol ; 13: 821681, 2022.
Article in English | MEDLINE | ID: covidwho-1708117

ABSTRACT

Peritoneal dialysis (PD) is a valuable 'home treatment' option, even more so during the ongoing Coronavirus pandemic. However, the long-term use of PD is limited by unfavourable tissue remodelling in the peritoneal membrane, which is associated with inflammation-induced angiogenesis. This appears to be driven primarily through vascular endothelial growth factor (VEGF), while the involvement of other angiogenic signaling pathways is still poorly understood. Here, we have identified the crucial contribution of mesothelial cell-derived angiogenic CXC chemokine ligand 1 (CXCL1) to peritoneal angiogenesis in PD. CXCL1 expression and peritoneal microvessel density were analysed in biopsies obtained by the International Peritoneal Biobank (NCT01893710 at www.clinicaltrials.gov), comparing 13 children with end-stage kidney disease before initiating PD to 43 children on chronic PD. The angiogenic potential of mesothelial cell-derived CXCL1 was assessed in vitro by measuring endothelial tube formation of human microvascular endothelial cells (HMECs) treated with conditioned medium from human peritoneal mesothelial cells (HPMCs) stimulated to release CXCL1 by treatment with either recombinant IL-17 or PD effluent. We found that the capillary density in the human peritoneum correlated with local CXCL1 expression. Both CXCL1 expression and microvessel density were higher in PD patients than in the age-matched patients prior to initiation of PD. Exposure of HMECs to recombinant CXCL1 or conditioned medium from IL-17-stimulated HPMCs resulted in increased endothelial tube formation, while selective inhibition of mesothelial CXCL1 production by specific antibodies or through silencing of relevant transcription factors abolished the proangiogenic effect of HPMC-conditioned medium. In conclusion, peritoneal mesothelium-derived CXCL1 promotes endothelial tube formation in vitro and associates with peritoneal microvessel density in uremic patients undergoing PD, thus providing novel targets for therapeutic intervention to prolong PD therapy.


Subject(s)
Chemokine CXCL1/metabolism , Neovascularization, Pathologic/pathology , Peritoneal Dialysis/methods , Peritoneum/blood supply , Renal Replacement Therapy/methods , COVID-19/pathology , Cells, Cultured , Child , Child, Preschool , Epithelium/metabolism , Humans , Infant , Interleukin-17/metabolism , Kidney Failure, Chronic/therapy , Peritoneum/pathology , Vascular Endothelial Growth Factor A/metabolism , Vascular Remodeling/physiology
4.
Bioconjug Chem ; 32(11): 2420-2431, 2021 11 17.
Article in English | MEDLINE | ID: covidwho-1526037

ABSTRACT

The heparan sulfate (HS) mimetic pixatimod (PG545) is a highly potent inhibitor of angiogenesis, tumor growth, and metastasis currently in clinical trials for cancer. PG545 has also demonstrated potent antiviral activity against numerous HS-dependent viruses, including SARS-CoV-2, and shows promise as an antiviral drug for the treatment of COVID-19. Structurally, PG545 consists of a fully sulfated tetrasaccharide conjugated to the steroid 5α-cholestan-3ß-ol. The reported synthesis of PG545 suffers from a low yield and poor selectivity in the critical glycosylation step. Given its clinical importance, new efficient routes for the synthesis of PG545 and analogues were developed. Particular attention was given to improving the key glycosylation step by using more stable protecting groups and optimized glycosyl donors.


Subject(s)
COVID-19 , Angiogenesis Inhibitors , Cell Line, Tumor , Heparitin Sulfate , Humans , Neovascularization, Pathologic
5.
Int J Mol Sci ; 22(9)2021 Apr 27.
Article in English | MEDLINE | ID: covidwho-1390655

ABSTRACT

The identification of thrombospondin-1 as an angiogenesis inhibitor in 1990 prompted interest in its role in cancer biology and potential as a therapeutic target. Decreased thrombospondin-1 mRNA and protein expression are associated with progression in several cancers, while expression by nonmalignant cells in the tumor microenvironment and circulating levels in cancer patients can be elevated. THBS1 is not a tumor suppressor gene, but the regulation of its expression in malignant cells by oncogenes and tumor suppressor genes mediates some of their effects on carcinogenesis, tumor progression, and metastasis. In addition to regulating angiogenesis and perfusion of the tumor vasculature, thrombospondin-1 limits antitumor immunity by CD47-dependent regulation of innate and adaptive immune cells. Conversely, thrombospondin-1 is a component of particles released by immune cells that mediate tumor cell killing. Thrombospondin-1 differentially regulates the sensitivity of malignant and nonmalignant cells to genotoxic stress caused by radiotherapy and chemotherapy. The diverse activities of thrombospondin-1 to regulate autophagy, senescence, stem cell maintenance, extracellular vesicle function, and metabolic responses to ischemic and genotoxic stress are mediated by several cell surface receptors and by regulating the functions of several secreted proteins. This review highlights progress in understanding thrombospondin-1 functions in cancer and the challenges that remain in harnessing its therapeutic potential.


Subject(s)
Neoplasms , Thrombospondin 1/physiology , Tumor Microenvironment/physiology , Animals , Cell Adhesion , Cell Movement , Humans , Integrins/metabolism , Mice , Neoplasms/blood supply , Neoplasms/immunology , Neoplasms/pathology , Neovascularization, Pathologic/metabolism , Neovascularization, Physiologic/genetics , T-Lymphocytes/immunology , Thrombospondin 1/genetics , Thrombospondin 1/metabolism
6.
Cells ; 10(7)2021 Jul 06.
Article in English | MEDLINE | ID: covidwho-1295777

ABSTRACT

Integrins belong to a group of cell adhesion molecules (CAMs) which is a large group of membrane-bound proteins. They are responsible for cell attachment to the extracellular matrix (ECM) and signal transduction from the ECM to the cells. Integrins take part in many other biological activities, such as extravasation, cell-to-cell adhesion, migration, cytokine activation and release, and act as receptors for some viruses, including severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2). They play a pivotal role in cell proliferation, migration, apoptosis, tissue repair and are involved in the processes that are crucial to infection, inflammation and angiogenesis. Integrins have an important part in normal development and tissue homeostasis, and also in the development of pathological processes in the eye. This review presents the available evidence from human and animal research into integrin structure, classification, function and their role in inflammation, infection and angiogenesis in ocular diseases. Integrin receptors and ligands are clinically interesting and may be promising as new therapeutic targets in the treatment of some eye disorders.


Subject(s)
Eye Diseases/metabolism , Inflammation/metabolism , Integrins/metabolism , Neovascularization, Pathologic/metabolism , Animals , COVID-19/metabolism , COVID-19/pathology , Cell Adhesion , Extracellular Matrix/metabolism , Extracellular Matrix/pathology , Eye Diseases/pathology , Humans , Inflammation/pathology , Integrins/analysis , Neovascularization, Pathologic/pathology , SARS-CoV-2/metabolism
7.
Angiogenesis ; 24(4): 755-788, 2021 11.
Article in English | MEDLINE | ID: covidwho-1286153

ABSTRACT

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is presenting as a systemic disease associated with vascular inflammation and endothelial injury. Severe forms of SARS-CoV-2 infection induce acute respiratory distress syndrome (ARDS) and there is still an ongoing debate on whether COVID-19 ARDS and its perfusion defect differs from ARDS induced by other causes. Beside pro-inflammatory cytokines (such as interleukin-1 ß [IL-1ß] or IL-6), several main pathological phenomena have been seen because of endothelial cell (EC) dysfunction: hypercoagulation reflected by fibrin degradation products called D-dimers, micro- and macrothrombosis and pathological angiogenesis. Direct endothelial infection by SARS-CoV-2 is not likely to occur and ACE-2 expression by EC is a matter of debate. Indeed, endothelial damage reported in severely ill patients with COVID-19 could be more likely secondary to infection of neighboring cells and/or a consequence of inflammation. Endotheliopathy could give rise to hypercoagulation by alteration in the levels of different factors such as von Willebrand factor. Other than thrombotic events, pathological angiogenesis is among the recent findings. Overexpression of different proangiogenic factors such as vascular endothelial growth factor (VEGF), basic fibroblast growth factor (FGF-2) or placental growth factors (PlGF) have been found in plasma or lung biopsies of COVID-19 patients. Finally, SARS-CoV-2 infection induces an emergency myelopoiesis associated to deregulated immunity and mobilization of endothelial progenitor cells, leading to features of acquired hematological malignancies or cardiovascular disease, which are discussed in this review. Altogether, this review will try to elucidate the pathophysiology of thrombotic complications, pathological angiogenesis and EC dysfunction, allowing better insight in new targets and antithrombotic protocols to better address vascular system dysfunction. Since treating SARS-CoV-2 infection and its potential long-term effects involves targeting the vascular compartment and/or mobilization of immature immune cells, we propose to define COVID-19 and its complications as a systemic vascular acquired hemopathy.


Subject(s)
COVID-19/metabolism , Myelopoiesis , Neovascularization, Pathologic/metabolism , Respiratory Distress Syndrome/metabolism , SARS-CoV-2/metabolism , Thrombosis/metabolism , COVID-19/pathology , COVID-19/therapy , Endothelial Cells/metabolism , Endothelial Cells/pathology , Endothelial Cells/virology , Fibrin Fibrinogen Degradation Products/metabolism , Fibroblast Growth Factor 2/metabolism , Humans , Interleukin-1beta/metabolism , Interleukin-6/metabolism , Membrane Proteins/metabolism , Neovascularization, Pathologic/pathology , Neovascularization, Pathologic/therapy , Neovascularization, Pathologic/virology , Respiratory Distress Syndrome/pathology , Respiratory Distress Syndrome/therapy , Respiratory Distress Syndrome/virology , Thrombosis/pathology , Thrombosis/therapy , Thrombosis/virology , Vascular Endothelial Growth Factor A/metabolism , von Willebrand Factor/metabolism
8.
Inflamm Res ; 70(7): 749-752, 2021 Jul.
Article in English | MEDLINE | ID: covidwho-1281256

ABSTRACT

Coronavirus disease 2019 (COVID-19) pandemic is still a world-class challenge. Inflammation, especially its severe form with excess release of pro-inflammatory cytokines (cytokine storm) which is a life-threatening condition, is among the most important suspects involved in COVID-19 pathogenesis. It has been shown that cytokine storm could cause notable morbidities such as acute respiratory distress syndrome (ARDS) which leads to hypoxia which is significantly associated with mortality of patients with COVID-19. Hypoxia-inducible factor 1α (HIF-1α) which activates following ARDS-induced hypoxia plays a crucial role in pathogenesis of cytokine storm. The expression of tumor necrosis factor α (TNF-α), interleukin 1 ß (IL-1ß), and IL-6 which are key elements of cytokine storm are by nuclear factor κß (NFκB). Interestingly, during the hypoxia, HIF-1α activates NFκB to induce expression of pro-angiogenic and pro-inflammatory factors. These released factors starts a autocrine/paracrine loop and causes deterioration of their etiological pathways of expression: cytokine storm and ARDS. To sum up, it seems HIF-1α is an important target to hit to ameliorate the mentioned pathways. Herein, we suggest perfluorocarbons (PFCs) which are among the organofluorine compounds as a possible co-treatment to reduce hypoxemia and then hypoxia. These substances are known for their high gas solving potential that make them able to be used as a synthetic artificial blood product. Due to the potential of PFCs to affect the fountain of important physiopathological pathway such as inflammation a hypoxia through affecting NFκB, they could be considered as multi-target co-treatment for ARD individuals with COVID-19. It is highly suggested to evaluate this hypothesis in following researches.


Subject(s)
COVID-19/drug therapy , Cytokine Release Syndrome/drug therapy , Cytokine Release Syndrome/etiology , Fluorocarbons/therapeutic use , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Neovascularization, Pathologic/drug therapy , Neovascularization, Pathologic/etiology , Animals , Cytokines/biosynthesis , Humans , Hypoxia/drug therapy , Hypoxia/etiology , NF-kappa B/drug effects , Protective Agents/therapeutic use , Respiratory Distress Syndrome/drug therapy , Respiratory Distress Syndrome/etiology
9.
Am J Physiol Lung Cell Mol Physiol ; 321(2): L358-L376, 2021 08 01.
Article in English | MEDLINE | ID: covidwho-1280497

ABSTRACT

Capillary endothelial cells possess a specialized metabolism necessary to adapt to the unique alveolar-capillary environment. Here, we highlight how endothelial metabolism preserves the integrity of the pulmonary circulation by controlling vascular permeability, defending against oxidative stress, facilitating rapid migration and angiogenesis in response to injury, and regulating the epigenetic landscape of endothelial cells. Recent reports on single-cell RNA-sequencing reveal subpopulations of pulmonary capillary endothelial cells with distinctive reparative capacities, which potentially offer new insight into their metabolic signature. Lastly, we discuss broad implications of pulmonary vascular metabolism on acute respiratory distress syndrome, touching on emerging findings of endotheliitis in coronavirus disease 2019 (COVID-19) lungs.


Subject(s)
COVID-19/complications , Endothelium, Vascular/metabolism , Neovascularization, Pathologic/pathology , Pulmonary Circulation , Respiratory Distress Syndrome/epidemiology , SARS-CoV-2/isolation & purification , COVID-19/transmission , COVID-19/virology , Endothelium, Vascular/pathology , Endothelium, Vascular/virology , Humans , Neovascularization, Pathologic/metabolism , Neovascularization, Pathologic/virology , Respiratory Distress Syndrome/metabolism , Respiratory Distress Syndrome/pathology , Respiratory Distress Syndrome/virology
10.
Microvasc Res ; 137: 104188, 2021 09.
Article in English | MEDLINE | ID: covidwho-1237818

ABSTRACT

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been led to a pandemic emergency. So far, different pathological pathways for SARS-CoV-2 infection have been introduced in which the excess release of pro-inflammatory cytokines (such as interleukin 1 ß [IL-1ß], IL-6, and tumor necrosis factor α [TNFα]) has earned most of the attentions. However, recent studies have identified new pathways with at least the same level of importance as cytokine storm in which endothelial cell (EC) dysfunction is one of them. In COVID-19, two main pathologic phenomena have been seen as a result of EC dysfunction: hyper-coagulation state and pathologic angiogenesis. The EC dysfunction-induced hypercoagulation state seems to be caused by alteration in the levels of different factors such as plasminogen activator inhibitor 1 (PAI-1), von Willebrand factor (vWF) antigen, soluble thrombomodulin, and tissue factor pathway inhibitor (TFPI). As data have shown, these thromboembolic events are associated with severity of disease severity or even death in COVID-19 patients. Other than thromboembolic events, pathologic angiogenesis is among the recent findings. Furthermore, over-expression/higher levels of different proangiogenic factors such as vascular endothelial growth factor (VEGF), hypoxia-inducible factor 1 α (HIF-1α), IL-6, TNF receptor super family 1A and 12, and angiotensin-converting enzyme 2 (ACE2) have been found in the lung biopsies/sera of both survived and non-survived COVID-19 patients. Also, there are some hypotheses regarding the role of nitric oxide in EC dysfunction and acute respiratory distress syndrome (ARDS) in SARS-CoV-2 infection. It has been demonstrated that different pathways involved in inflammation are generally common with EC dysfunction and angiogenesis. Altogether, considering the common possible upstream pathways in cytokine storm, pathologic angiogenesis, and EC dysfunction, it seems that targeting these molecules (such as nuclear factor κB) could be more effective in the management of patients with COVID-19.


Subject(s)
COVID-19/blood , COVID-19/physiopathology , Endothelial Cells/metabolism , Neovascularization, Pathologic , Angiotensin-Converting Enzyme 2/metabolism , Biomarkers/metabolism , Blood Coagulation , Cytokine Release Syndrome , Humans , Inflammation , Interleukin-1beta/metabolism , Interleukin-6/metabolism , Lipoproteins/metabolism , Nitric Oxide/metabolism , Plasminogen Activator Inhibitor 1/metabolism , SARS-CoV-2 , Tumor Necrosis Factor-alpha/metabolism , von Willebrand Factor/metabolism
11.
Cells ; 10(5)2021 05 07.
Article in English | MEDLINE | ID: covidwho-1223961

ABSTRACT

The flavonoid naringenin (Nar), present in citrus fruits and tomatoes, has been identified as a blocker of an emerging class of human intracellular channels, namely the two-pore channel (TPC) family, whose role has been established in several diseases. Indeed, Nar was shown to be effective against neoangiogenesis, a process essential for solid tumor progression, by specifically impairing TPC activity. The goal of the present review is to illustrate the rationale that links TPC channels to the mechanism of coronavirus infection, and how their inhibition by Nar could be an efficient pharmacological strategy to fight the current pandemic plague COVID-19.


Subject(s)
COVID-19/drug therapy , Calcium Channel Blockers/pharmacology , Calcium Channels/metabolism , Flavanones/pharmacology , Neoplasms/drug therapy , Antineoplastic Agents/pharmacology , Antineoplastic Agents/therapeutic use , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , Arabidopsis/metabolism , COVID-19/epidemiology , COVID-19/pathology , COVID-19/virology , Calcium Channel Blockers/therapeutic use , Drug Evaluation, Preclinical , Endosomes/drug effects , Endosomes/metabolism , Endosomes/virology , Flavanones/therapeutic use , Humans , Lysosomes/drug effects , Lysosomes/metabolism , Lysosomes/virology , Neoplasms/blood supply , Neoplasms/pathology , Neovascularization, Pathologic/drug therapy , Neovascularization, Pathologic/pathology , Pandemics/prevention & control , SARS-CoV-2/pathogenicity , Vacuoles/metabolism , Virus Internalization/drug effects
12.
Clin Cancer Res ; 27(10): 2706-2711, 2021 05 15.
Article in English | MEDLINE | ID: covidwho-1112356

ABSTRACT

The dramatic impact of the COVID-19 pandemic has resulted in an "all hands on deck" approach to find new therapies to improve outcomes in this disease. In addition to causing significant respiratory pathology, infection with SARS-CoV-2 (like infection with other respiratory viruses) directly or indirectly results in abnormal vasculature, which may contribute to hypoxemia. These vascular effects cause significant morbidity and may contribute to mortality from the disease. Given that abnormal vasculature and poor oxygenation are also hallmarks of solid tumors, lessons from the treatment of cancer may help identify drugs that can be repurposed to treat COVID-19. Although the mechanisms that result in vascular abnormalities in COVID-19 are not fully understood, it is possible that there is dysregulation of many of the same angiogenic and thrombotic pathways as seen in patients with cancer. Many anticancer therapeutics, including androgen deprivation therapy (ADT) and immune checkpoint blockers (ICB), result in vascular normalization in addition to their direct effects on tumor cells. Therefore, these therapies, which have been extensively explored in clinical trials of patients with cancer, may have beneficial effects on the vasculature of patients with COVID-19. Furthermore, these drugs may have additional effects on the disease course, as some ADTs may impact viral entry, and ICBs may accelerate T-cell-mediated viral clearance. These insights from the treatment of cancer may be leveraged to abrogate the vascular pathologies found in COVID-19 and other forms of hypoxemic respiratory failure.


Subject(s)
Androgen Antagonists/therapeutic use , Blood Vessels/drug effects , COVID-19/prevention & control , Neoplasms, Hormone-Dependent/drug therapy , Neovascularization, Pathologic/drug therapy , Prostatic Neoplasms/drug therapy , Blood Vessels/pathology , Blood Vessels/physiopathology , COVID-19/epidemiology , COVID-19/virology , Clinical Trials as Topic , Disease Progression , Humans , Male , Neoplasms, Hormone-Dependent/blood supply , Outcome Assessment, Health Care , Pandemics , Prostatic Neoplasms/blood supply , Risk Factors , SARS-CoV-2/physiology
14.
Viruses ; 13(2)2021 Jan 20.
Article in English | MEDLINE | ID: covidwho-1067780

ABSTRACT

Although ACE2 (angiotensin converting enzyme 2) is considered the primary receptor for CoV-2 cell entry, recent reports suggest that alternative pathways may contribute. This paper considers the hypothesis that viral binding to cell-surface integrins may contribute to the high infectivity and widespread extra-pulmonary impacts of the SARS-CoV-2 virus. This potential is suggested on the basis of the emergence of an RGD (arginine-glycine-aspartate) sequence in the receptor-binding domain of the spike protein. RGD is a motif commonly used by viruses to bind cell-surface integrins. Numerous signaling pathways are mediated by integrins and virion binding could lead to dysregulation of these pathways, with consequent tissue damage. Integrins on the surfaces of pneumocytes, endothelial cells and platelets may be vulnerable to CoV-2 virion binding. For instance, binding of intact virions to integrins on alveolar cells could enhance viral entry. Binding of virions to integrins on endothelial cells could activate angiogenic cell signaling pathways; dysregulate integrin-mediated signaling pathways controlling developmental processes; and precipitate endothelial activation to initiate blood clotting. Such a procoagulant state, perhaps together with enhancement of platelet aggregation through virions binding to integrins on platelets, could amplify the production of microthrombi that pose the threat of pulmonary thrombosis and embolism, strokes and other thrombotic consequences. The susceptibility of different tissues to virion-integrin interactions may be modulated by a host of factors, including the conformation of relevant integrins and the impact of the tissue microenvironment on spike protein conformation. Patient-specific differences in these factors may contribute to the high variability of clinical presentation. There is danger that the emergence of receptor-binding domain mutations that increase infectivity may also enhance access of the RGD motif for integrin binding, resulting in viral strains with ACE2 independent routes of cell entry and novel integrin-mediated biological and clinical impacts. The highly infectious variant, B.1.1.7 (or VUI 202012/01), includes a receptor-binding domain amino acid replacement, N501Y, that could potentially provide the RGD motif with enhanced access to cell-surface integrins, with consequent clinical impacts.


Subject(s)
Integrins/metabolism , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism , Blood Coagulation Disorders/virology , COVID-19/blood , COVID-19/pathology , COVID-19/virology , Humans , Neovascularization, Pathologic/virology , Oligopeptides , Protein Binding , Receptors, Virus/metabolism , SARS-CoV-2/pathogenicity , Signal Transduction , Virus Internalization
17.
Arterioscler Thromb Vasc Biol ; 41(1): 415-429, 2021 01.
Article in English | MEDLINE | ID: covidwho-1027162

ABSTRACT

OBJECTIVE: The study's aim was to analyze the capacity of human valve interstitial cells (VICs) to participate in aortic valve angiogenesis. Approach and Results: VICs were isolated from human aortic valves obtained after surgery for calcific aortic valve disease and from normal aortic valves unsuitable for grafting (control VICs). We examined VIC in vitro and in vivo potential to differentiate in endothelial and perivascular lineages. VIC paracrine effect was also examined on human endothelial colony-forming cells. A pathological VIC (VICp) mesenchymal-like phenotype was confirmed by CD90+/CD73+/CD44+ expression and multipotent-like differentiation ability. When VICp were cocultured with endothelial colony-forming cells, they formed microvessels by differentiating into perivascular cells both in vivo and in vitro. VICp and control VIC conditioned media were compared using serial ELISA regarding quantification of endothelial and angiogenic factors. Higher expression of VEGF (vascular endothelial growth factor)-A was observed at the protein level in VICp-conditioned media and confirmed at the mRNA level in VICp compared with control VIC. Conditioned media from VICp induced in vitro a significant increase in endothelial colony-forming cell proliferation, migration, and sprouting compared with conditioned media from control VIC. These effects were inhibited by blocking VEGF-A with blocking antibody or siRNA approach, confirming VICp involvement in angiogenesis by a VEGF-A dependent mechanism. CONCLUSIONS: We provide here the first proof of an angiogenic potential of human VICs isolated from patients with calcific aortic valve disease. These results point to a novel function of VICp in valve vascularization during calcific aortic valve disease, with a perivascular differentiation ability and a VEGF-A paracrine effect. Targeting perivascular differentiation and VEGF-A to slow calcific aortic valve disease progression warrants further investigation.


Subject(s)
Aortic Valve Stenosis/metabolism , Aortic Valve/metabolism , Aortic Valve/pathology , Calcinosis/metabolism , Cell Differentiation , Cell Lineage , Endothelial Progenitor Cells/metabolism , Neovascularization, Pathologic , Vascular Endothelial Growth Factor A/metabolism , Adult , Aged , Aged, 80 and over , Animals , Aortic Valve Stenosis/pathology , Calcinosis/pathology , Case-Control Studies , Cells, Cultured , Coculture Techniques , Endothelial Progenitor Cells/pathology , Endothelial Progenitor Cells/transplantation , Female , Humans , Male , Mice, Nude , Middle Aged , Osteogenesis , Paracrine Communication , Phenotype , Signal Transduction , Vascular Endothelial Growth Factor A/genetics
18.
Cells ; 9(12)2020 12 04.
Article in English | MEDLINE | ID: covidwho-965318

ABSTRACT

Human herpesvirus 6 (HHV-6) is a ß-herpesvirus that is highly prevalent in the human population. HHV-6 comprises two recognized species (HHV-6A and HHV-6B). Despite different cell tropism and disease association, HHV-6A/B show high genome homology and harbor the conserved U94 gene, which is limited to HHV-6 and absent in all the other human herpesviruses. U94 has key functions in the virus life cycle and associated diseases, having demonstrated or putative roles in virus replication, integration, and reactivation. During natural infection, U94 elicits an immune response, and the prevalence and extent of the anti-U94 response are associated with specific diseases. Notably, U94 can entirely reproduce some virus effects at the cell level, including inhibition of cell migration, induction of cytokines and HLA-G expression, and angiogenesis inhibition, supporting a direct U94 role in the development of HHV-6-associated diseases. Moreover, specific U94 properties, such as the ability to modulate angiogenesis pathways, have been exploited to counteract cancer development. Here, we review the information available on this key HHV-6 gene, highlighting its potential uses.


Subject(s)
Herpesvirus 6, Human/genetics , Herpesvirus 6, Human/immunology , Roseolovirus Infections/virology , Viral Proteins/physiology , Animals , Cell Line , Cell Movement , Cytokines/metabolism , Genome, Viral , HLA-G Antigens/metabolism , Humans , Immune System , Mice , Neovascularization, Pathologic , Rats , Roseolovirus Infections/epidemiology , Viral Proteins/genetics , Virus Integration , Virus Replication
19.
Angiogenesis ; 24(1): 13-15, 2021 02.
Article in English | MEDLINE | ID: covidwho-866224

ABSTRACT

Hereditary hemorrhagic telangiectasia (HHT) is a rare autosomal-dominant disease characterized by pathologic angiogenesis that provokes vascular overgrowth. The evidence about the influence of Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) in patients with rare diseases is scarce. We aimed to know the prevalence of coronavirus disease 2019 (COVID-19) in HHT patients. The HHT pathogenic angiogenesis and endothelial injury in COVID-19 are discussed using data from RiHHTa (Computerized Registry of Hereditary Hemorrhagic Telangiectasia) registry. RiHHTa is an open, multicenter, prospective, observational registry including adult patients with HHT. A 27-item survey that captured clinical data of admitted HHT patients for COVID-19 was distributed to all RiHHTa investigators from June 8th to June 24th 2020. Only one out of 1177 HHT patients was admitted for COVID-19 pneumonia. She is a 74 years-old woman with a pathogenic variant in ACVRL1 gene. Her clinical course did not involve mechanical ventilation or worsening epistaxis, and she was successfully discharged after two weeks. The endothelial damage and the consequent angiogenic process in COVID-19 patients deserve further investigation.


Subject(s)
Activin Receptors, Type II/genetics , COVID-19/complications , COVID-19/epidemiology , Neovascularization, Pathologic , Telangiectasia, Hereditary Hemorrhagic/complications , Telangiectasia, Hereditary Hemorrhagic/epidemiology , Aged , Female , Humans , Patient Admission , Prevalence , Prospective Studies , Registries , Spain , Surveys and Questionnaires
20.
Mol Biol Rep ; 47(10): 8301-8304, 2020 Oct.
Article in English | MEDLINE | ID: covidwho-754390

ABSTRACT

The interest on the role of angiogenesis in the pathogenesis and progression of human interstitial lung diseases is growing, with conventional sprouting (SA) and non-sprouting intussusceptive angiogenesis (IA) being differently represented in specific pulmonary injury patterns. The role of viruses as key regulators of angiogenesis is known for several years. A significantly enhanced amount of new vessel growth, through a mechanism of IA, has been reported in lungs of patients who died from Covid-19; among the angiogenesis-related genes, fibroblast growth factor 2 (FGF2) was found to be upregulated. These findings are intriguing. FGF2 plays a role in some viral infections: the upregulation is involved in the MERS-CoV-induced strong apoptotic response crucial for its highly lytic replication cycle in lung cells, whereas FGF2 is protective against the acute lung injury induced by H1N1 influenza virus, improving the lung wet-to-dry weight ratio. FGF2 plays a role also in regulating IA, acting on pericytes (crucial for the formation of intraluminal pillars), and endothelium, and FGF2-induced angiogenesis may be promoted by inflammation and hypoxia. IA is a faster and probably more efficient process than SA, able to modulate vascular remodeling through pruning of redundant or inefficient blood vessels. We can speculate that IA might have the function of restoring a functional vascular plexus consequently to extensive endothelialitis and alveolar capillary micro-thrombosis observed in Covid-19. Anti-Vascular endothelial growth factor (anti-VEGF) strategies are currently investigated for treatment of severe and critically ill Covid-19 patients, but also FGF2, and its expression and/or signaling, might represent a promising target.


Subject(s)
Coronavirus Infections/pathology , Fibroblast Growth Factor 2/metabolism , Neovascularization, Pathologic/virology , Pneumonia, Viral/pathology , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , COVID-19 , Coronavirus Infections/drug therapy , Coronavirus Infections/etiology , Drug Delivery Systems , Fibroblast Growth Factor 2/antagonists & inhibitors , Humans , Intussusception/virology , Neovascularization, Pathologic/genetics , Pandemics , Pneumonia, Viral/drug therapy , Pneumonia, Viral/etiology
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