scholarly journals Hemagglutinin-Dependent Tropism of H5N1 Avian Influenza Virus for Human Endothelial Cells

2009 ◽  
Vol 83 (24) ◽  
pp. 12947-12955 ◽  
Author(s):  
Manuela Ocaña-Macchi ◽  
Michael Bel ◽  
Laurence Guzylack-Piriou ◽  
Nicolas Ruggli ◽  
Matthias Liniger ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Avian Influenza ◽  
Cell Activation ◽  
De Novo ◽  
Binding Capacity ◽  
Multiorgan Failure ◽  
Influenza Viruses ◽  
Human Influenza ◽  
Receptor Specificity ◽  
Activation Markers

ABSTRACT Although current H5N1 highly pathogenic avian influenza viruses (HPAIV) are inefficiently transmitted to humans, infected individuals can suffer from severe disease, often progressing rapidly to acute respiratory distress syndrome and multiorgan failure. This is in contrast with the situation with human influenza viruses, which in immunocompetent individuals usually cause only a respiratory disease which is less aggressive than that observed with avian H5N1 viruses. While the biological basis of inefficient transmission is well documented, the mechanisms by which the H5N1 viruses cause fatal disease remain unclear. In the present study, we demonstrate that human pulmonary microvascular endothelial cells (hPMEC) had a clearly higher susceptibility to infection by H5N1 HPAIV than to infection by human influenza viruses. This was measurable by de novo intracellular nucleoprotein production and virus replication. It was also related to a relatively higher binding capacity to cellular receptors. After infection of hPMEC, cell activation markers E-selectin and P-selectin were upregulated, and the proinflammatory cytokines interleukin-6 and beta interferon were secreted. H5N1 virus infection was also associated with an elevated rate of cell death. Reverse genetics analyses demonstrated a major role for the viral hemagglutinin in this cell tropism. Overall, avian H5N1 viruses have a particular receptor specificity targeting endothelial cells that is different from human influenza viruses, and this H5N1 receptor specificity could contribute to disease pathogenesis.

scholarly journals Constitutively Expressed IFITM3 Protein in Human Endothelial Cells Poses an Early Infection Block to Human Influenza Viruses

2016 ◽  
Vol 90 (24) ◽  
pp. 11157-11167 ◽  
Author(s):  
Xiangjie Sun ◽  
Hui Zeng ◽  
Amrita Kumar ◽  
Jessica A. Belser ◽  
Taronna R. Maines ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Influenza Virus ◽  
Virus Infection ◽  
Avian Influenza ◽  
Influenza Virus Infection ◽  
Influenza Viruses ◽  
Human Influenza ◽  
Avian Influenza Viruses ◽  
Human Influenza Virus ◽  
Pulmonary Endothelial Cells

ABSTRACTA role for pulmonary endothelial cells in the orchestration of cytokine production and leukocyte recruitment during influenza virus infection, leading to severe lung damage, has been recently identified. As the mechanistic pathway for this ability is not fully known, we extended previous studies on influenza virus tropism in cultured human pulmonary endothelial cells. We found that a subset of avian influenza viruses, including potentially pandemic H5N1, H7N9, and H9N2 viruses, could infect human pulmonary endothelial cells (HULEC) with high efficiency compared to human H1N1 or H3N2 viruses. In HULEC, human influenza viruses were capable of binding to host cellular receptors, becoming internalized and initiating hemifusion but failing to uncoat the viral nucleocapsid and to replicate in host nuclei. Unlike numerous cell types, including epithelial cells, we found that pulmonary endothelial cells constitutively express a high level of the restriction protein IFITM3 in endosomal compartments. IFITM3 knockdown by small interfering RNA (siRNA) could partially rescue H1N1 virus infection in HULEC, suggesting IFITM3 proteins were involved in blocking human influenza virus infection in endothelial cells. In contrast, selected avian influenza viruses were able to escape IFITM3 restriction in endothelial cells, possibly by fusing in early endosomes at higher pH or by other, unknown mechanisms. Collectively, our study demonstrates that the human pulmonary endothelium possesses intrinsic immunity to human influenza viruses, in part due to the constitutive expression of IFITM3 proteins. Notably, certain avian influenza viruses have evolved to escape this restriction, possibly contributing to virus-induced pneumonia and severe lung disease in humans.IMPORTANCEAvian influenza viruses, including H5N1 and H7N9, have been associated with severe respiratory disease and fatal outcomes in humans. Although acute respiratory distress syndrome (ARDS) and progressive pulmonary endothelial damage are known to be present during severe human infections, the role of pulmonary endothelial cells in the pathogenesis of avian influenza virus infections is largely unknown. By comparing human seasonal influenza strains to avian influenza viruses, we provide greater insight into the interaction of influenza virus with human pulmonary endothelial cells. We show that human influenza virus infection is blocked during the early stages of virus entry, which is likely due to the relatively high expression of the host antiviral factors IFITMs (interferon-induced transmembrane proteins) located in membrane-bound compartments inside cells. Overall, this study provides a mechanism by which human endothelial cells limit replication of human influenza virus strains, whereas avian influenza viruses overcome these restriction factors in this cell type.

scholarly journals Phenotypic Effects of Substitutions within the Receptor Binding Site of Highly Pathogenic Avian Influenza H5N1 Virus Observed during Human Infection

2020 ◽  
Vol 94 (13) ◽  
Author(s):  
Dirk Eggink ◽  
Monique Spronken ◽  
Roosmarijn van der Woude ◽  
Jocynthe Buzink ◽  
Frederik Broszeit ◽  
...  
Keyword(s):  
Amino Acid ◽  
Avian Influenza ◽  
Binding Site ◽  
Receptor Binding ◽  
Human Infection ◽  
Influenza Viruses ◽  
Receptor Specificity ◽  
Receptor Binding Site ◽  
Human Type ◽  
Human Infections

ABSTRACT Highly pathogenic avian influenza (HPAI) viruses are enzootic in wild birds and poultry and continue to cause human infections with high mortality. To date, more than 850 confirmed human cases of H5N1 virus infection have been reported, of which ∼60% were fatal. Global concern persists that these or similar avian influenza viruses will evolve into viruses that can transmit efficiently between humans, causing a severe influenza pandemic. It was shown previously that a change in receptor specificity is a hallmark for adaptation to humans and evolution toward a transmittable virus. Substantial genetic diversity was detected within the receptor binding site of hemagglutinin of HPAI A/H5N1 viruses, evolved during human infection, as detected by next-generation sequencing. Here, we investigated the functional impact of substitutions that were detected during these human infections. Upon rescue of 21 mutant viruses, most substitutions in the receptor binding site (RBS) resulted in viable virus, but virus replication, entry, and stability were often impeded. None of the tested substitutions individually resulted in a clear switch in receptor preference as measured with modified red blood cells and glycan arrays. Although several combinations of the substitutions can lead to human-type receptor specificity, accumulation of multiple amino acid substitutions within a single hemagglutinin during human infection is rare, thus reducing the risk of virus adaptation to humans. IMPORTANCE H5 viruses continue to be a threat for public health. Because these viruses are immunologically novel to humans, they could spark a pandemic when adapted to transmit between humans. Avian influenza viruses need several adaptive mutations to bind to human-type receptors, increase hemagglutinin (HA) stability, and replicate in human cells. However, knowledge on adaptive mutations during human infections is limited. A previous study showed substantial diversity within the receptor binding site of H5N1 during human infection. We therefore analyzed the observed amino acid changes phenotypically in a diverse set of assays, including virus replication, stability, and receptor specificity. None of the tested substitutions resulted in a clear step toward a human-adapted virus capable of aerosol transmission. It is notable that acquiring human-type receptor specificity needs multiple amino acid mutations, and that variability at key position 226 is not tolerated, reducing the risk of them being acquired naturally.

scholarly journals A New Role for the Aldosterone/Mineralocorticoid Receptor Pathway in the Development of Mitral Valve Prolapse

2020 ◽  
Vol 127 (3) ◽  
Author(s):  
Jaime Ibarrola ◽  
Amaia Garcia-Peña ◽  
Lara Matilla ◽  
Benjamin Bonnard ◽  
Rafael Sádaba ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Mitral Valve ◽  
Mitral Valve Prolapse ◽  
Mineralocorticoid Receptor ◽  
Cell Activation ◽  
Cardiac Fibrosis ◽  
Interstitial Cell ◽  
Activation Markers ◽  
Mesenchymal Transition ◽  
Endothelial Mesenchymal Transition

Rationale: Mitral valve prolapse (MVP) is one of the most common valvular disorders. However, the molecular and cellular mechanisms involved in fibromyxomatous changes in the mitral leaflet tissue have not been elucidated. Aldosterone (Aldo) promotes fibrosis in myocardium, and MR (mineralocorticoid receptor) antagonists (MRAs) improve cardiac function by decreasing cardiac fibrosis. Objective: We investigated the role of the Aldo/MR in the fibromyxomatous modifications associated with MVP. Methods and Results: Aldo enhanced valvular interstitial cell activation markers and induced endothelial-mesenchymal transition in valvular endothelial cells, resulting in increased proteoglycan secretion. MRA blocked all the above effects. Cytokine arrays showed CT-1 (cardiotrophin-1) to be a mediator of Aldo-induced valvular interstitial cell activation and proteoglycan secretion and CD (cluster of differentiation) 14 to be a mediator of Aldo-induced endothelial-mesenchymal transition and proteoglycan secretion in valvular endothelial cells. In an experimental mouse model of MVP generated by nordexfenfluramine administration, MRA treatment reduced mitral valve thickness and proteoglycan content. Endothelial-specific MR deletion prevented fibromyxomatous changes induced by nordexfenfluramine administration. Moreover, proteoglycan expression was slightly lower in the mitral valves of MVP patients treated with MRA. Conclusions: These findings demonstrate, for the first time, that the Aldo/MR pathway regulates the phenotypic, molecular, and histological changes of valvular interstitial cells and valvular endothelial cells associated with MVP development. MRA treatment appears to be a promising option to reduce fibromyxomatous alterations in MVP.

Endothelial Progenitor Cells in Paroxysmal Nocturnal Hemoglobinuria

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2397-2397
Author(s):  
Sophie Gandrille ◽  
Régis Peffault de Latour ◽  
Emeline Levionnois ◽  
Anna D. Petropoulou ◽  
Isabelle Galy-Fauroux ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Progenitor Cells ◽  
Endothelial Progenitor Cells ◽  
Gene Mutation ◽  
Paroxysmal Nocturnal Hemoglobinuria ◽  
Cell Activation ◽  
Endothelial Progenitor ◽  
Activation Markers ◽  
Hematopoietic Stem ◽  
Common Precursor

Abstract Abstract 2397 Introduction: Paroxysmal nocturnal hemoglobinuria (PNH), a very rare disease, is characterized by hemolytic anemia, bone marrow failure, and venous thromboembolism. The disease is caused by somatic mutation of the X-linked gene PIG-A encoding a key enzyme responsible for the biosynthesis of the GPI-anchored proteins (GPI-APs), affecting hematopoietic stem cells (HSC). Venous thromboembolisms occur in unusual sites and the mechanism remains to be elucidated. A previous study showed an increase of endothelial cell activation markers in PNH patients (Helley et al., Haematologica 2010;95:574-581), however endothelial cells remain poorly studied in this disease. In polycythemia vera, associating JAK-2 mutation in HSC and thrombosis occurrence, Sozer and coworkers showed that liver endothelial cells bore the same JAK-2 mutation than the HSC (Sozer et al, Blood Cells, Molecules and Diseases, 2009;43:304-312). This suggests the existence of a common precursor between endothelial progenitor cells and HSC, the hemangioblast. In PNH, PIG-A gene mutations might be present in endothelial cells. To test this hypothesis we have used endothelial progenitor cells circulating in blood, also called endothelial-colony forming cells (ECFC), as witnesses of endothelial cells status. Methods: Peripheral blood mononuclear cells (PBMC) and neutrophiles (PMNL), from patients with classical PNH, were fractionated. PMNL were used to isolate DNA, while PBMC were plated on gelatine-coated plates to be cultured until appearance of ECFC colonies (usually 15–20 days), and then cultured to perform: (i) expression of GPI-anchored protein by flow cytometry; (ii) sequencing of the exons and flanking regions of the PIG-A gene from PMNL and ECFC. Results: Twelve PNH patients were enrolled (8 women, 4 men). Among them, 3 have venous thrombotic events (2 Budd-Chiari syndromes and one mesenteric veins thrombosis). ECFC colonies were obtained from 6 out of the 12 patients, a normal output due to the small number of ECFC in whole blood. Mutations identified by sequencing the PIG-A gene of PMNLs from these 6 patients are shown in Table 1, as well as clinical characteristics. In 5 patients only (two with previous Budd-Chiari syndrome), we obtained sufficient amounts of ECFC to isolate DNA. None of the ECFC colonies bore the identified mutations (one exhibited a very faint peak of mutated nucleotide on electrophoregram but mRNA transcripts analysis from this ECFC colony revealed traces amounts of CD45 and CD11b mRNA, suggesting a contamination by leukocytes). Conclusion: This is the first study reporting the absence of PIG-A gene mutation in ECFC from PNH patients, indicating that the mature endothelial cells are not bearing the PIG-A mutation. These cells are thus involved in thrombosis probably by free hemoglobin and thrombin cell activation, rather than by direct damage caused by PIG-A gene mutation. These results also indicate that, in PNH, the PIG-A gene mutation occurs most probably after the common precursor between endothelial progenitor cells and HSC. Disclosures: Peffault de Latour: Alexion: Consultancy, Research Funding. Fischer:Alexion: Consultancy. Helley:Alexion: Consultancy.

Receptor specificity of erythrocytes from different species related to swine, equine, avian and human influenza viruses

2003 ◽  
Vol 8 (1-2) ◽  
Author(s):  
Dalva A. P. Mancini ◽  
Rita M. Z. Mendonça ◽  
Andrea L. F. Dias ◽  
Adélia H. N. Kawamoto ◽  
José R. Pinto ◽  
...  
Keyword(s):  
Influenza Viruses ◽  
Human Influenza ◽  
Receptor Specificity

scholarly journals Receptor specificity and erythrocyte binding preferences of avian influenza viruses isolated from India

2012 ◽  
Vol 9 (1) ◽  
pp. 251 ◽  
Author(s):  
Shailesh D Pawar ◽  
Saurabh S Parkhi ◽  
Santosh S Koratkar ◽  
Akhilesh C Mishra
Keyword(s):  
Avian Influenza ◽  
Influenza Viruses ◽  
Receptor Specificity ◽  
Avian Influenza Viruses ◽  
Erythrocyte Binding

scholarly journals Enhancing Antitumor Efficacy of Heavily Vascularized Tumors by RAMBO Virus through Decreased Tumor Endothelial Cell Activation

Cancers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1040
Author(s):  
Mitra Nair ◽  
Maninder Khosla ◽  
Yoshihiro Otani ◽  
Margaret Yeh ◽  
Flora Park ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Solid Tumors ◽  
Cell Activation ◽  
Leukocyte Adhesion ◽  
Oncolytic Viruses ◽  
Endothelial Cell Activation ◽  
Microscopy Imaging ◽  
Activation Markers

Vascularization is a common pathology for many solid tumors, and therefore anti-angiogenic strategies are being investigated as a therapeutic target for treatment. Numerous studies are also being conducted regarding the effects of oncolytic viruses, including ImlygicTM, an FDA approved oncolytic herpes simplex virus-1 (oHSV) for the treatment of highly vascularized tumors such as Kaposi sarcoma (NCT04065152), and brain tumors. To our knowledge, the effects of combining oncolytic HSV with angiogenesis inhibition on endothelial cell activation has not been previously described. Here, we tested the effects of Rapid Antiangiogenesis Mediated By Oncolytic Virus (RAMBO), an oHSV which expresses a potent anti-angiogenic gene Vasculostatin on endothelial cell activation in heavily vascularized solid tumors. oHSV treatment induces endothelial cell activation, which inhibits virus propagation and oncolysis in adjacent tumor cells in vitro. Consistently, this was also observed in intravital imaging of intracranial tumor-bearing mice in vivo where infected tumor endothelial cells could efficiently clear the virus without cell lysis. Quantitative real-time PCR (Q-PCR), leukocyte adhesion assay, and fluorescent microscopy imaging data, however, revealed that RAMBO virus significantly decreased expression of endothelial cell activation markers and leukocyte adhesion, which in turn increased virus replication and cytotoxicity in endothelial cells. In vivo RAMBO treatment of subcutaneously implanted sarcoma tumors significantly reduced tumor growth in mice bearing sarcoma compared to rHSVQ. In addition, histological analysis of RAMBO-treated tumor tissues revealed large areas of necrosis and a statistically significant reduction in microvessel density (MVD). This study provides strong preclinical evidence of the therapeutic benefit for the use of RAMBO virus as a treatment option for highly vascularized tumors.

scholarly journals Selection of H3 avian influenza viruses with SAα2,6Gal receptor specificity in pigs

Virology ◽  
2013 ◽  
Vol 444 (1-2) ◽  
pp. 404-408 ◽  
Author(s):  
Shintaro Shichinohe ◽  
Masatoshi Okamatsu ◽  
Yoshihiro Sakoda ◽  
Hiroshi Kida
Keyword(s):  
Avian Influenza ◽  
Influenza Viruses ◽  
Receptor Specificity ◽  
Avian Influenza Viruses ◽  
Selection Of

scholarly journals HA-Dependent Tropism of H5N1 and H7N9 Influenza Viruses to Human Endothelial Cells Is Determined by Reduced Stability of the HA, Which Allows the Virus To Cope with Inefficient Endosomal Acidification and Constitutively Expressed IFITM3

2019 ◽  
Vol 94 (1) ◽  
Author(s):  
Luca Hensen ◽  
Tatyana Matrosovich ◽  
Katrin Roth ◽  
Hans-Dieter Klenk ◽  
Mikhail Matrosovich
Keyword(s):  
Endothelial Cells ◽  
Mdck Cells ◽  
Conformational Stability ◽  
Influenza Viruses ◽  
Viral Infectivity ◽  
Human Endothelial Cells ◽  
Receptor Specificity ◽  
Ph Optimum ◽  
Endosomal Acidification ◽  
Endosomal Ph

ABSTRACT Previous studies revealed that certain avian influenza A viruses (IAVs), including zoonotic H5N1 and H7N9 IAVs, infect cultured human lung microvascular endothelial cells (HULEC) more efficiently than other IAVs and that tropism to HULEC is determined by viral hemagglutinin (HA). To characterize mechanisms of HA-mediated endotheliotropism, we used 2:6 recombinant IAVs harboring HAs from distinctive avian and human viruses and found that efficient infection of HULEC correlated with low conformational stability of the HA. We next studied effects on viral infectivity of single-point amino acid substitutions in the HA of 2:6 recombinant virus A/Vietnam/1203/2004-PR8 (H5N1). Substitutions H8Q, H103Y, T315I, and K582I (K58I in the HA2 subunit), which increased stability of the HA, markedly reduced viral infectivity for HULEC, whereas substitutions K189N and K218Q, which altered typical H5N1 virus-like receptor specificity and reduced binding avidity of the HA, led to only marginal reduction of infectivity. None of these substitutions affected virus infection in MDCK cells. We confirmed the previous observation of elevated basal expression of IFITM3 protein in HULEC and found that endosomal acidification is less efficient in HULEC than in MDCK cells. In accord with these findings, counteraction of IFITM3-mediated restriction by amphotericin B and reduction of endosomal pH by moderate acidification of the extracellular medium enhanced infectivity of viruses with stable HA for HULEC without significant effect on infectivity for MDCK cells. Collectively, our results indicate that relatively high pH optimum of fusion of the HA of zoonotic H5N1 and H7N9 IAVs allows them to overcome antiviral effects of inefficient endosomal acidification and IFITM3 in human endothelial cells. IMPORTANCE Receptor specificity of the HA of IAVs is known to be a critical determinant of viral cell tropism. Here, we show that fusion properties of the HA may also play a key role in the tropism. Thus, we demonstrate that IAVs having a relatively low pH optimum of fusion cannot efficiently infect human endothelial cells owing to their relatively high endosomal pH and increased expression of fusion-inhibiting IFITM3 protein. These restrictions can be overcome by IAVs with elevated pH of fusion, such as zoonotic H5N1 and H7N9. Our results illustrate that the infectivity of IAVs depends on an interplay between HA conformational stability, endosomal acidification and IFITM3 expression in target cells, and the extracellular pH. Given significant variation of levels of HA stability among animal, human, and zoonotic IAVs, our findings prompt further studies on the fusion-dependent tropism of IAVs to different cell types in humans and its role in viral host range and pathogenicity.

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