Pathogenic hantaviruses bind plexin–semaphorin–integrin domains present at the apex of inactive, bent αvβ3 integrin conformers

Abstract

The ␣v␤3 integrins are linked to human bleeding disorders, and pathogenic hantaviruses regulate the function of ␣v␤3 integrins and cause acute vascular diseases. ␣v␤3 integrins are present in either extended (active) or dramatically bent (inactive) structures, and interconversion of ␣v␤3 conformers dynamically regulates integrin functions. Here, we show that hantaviruses bind human ␣v␤3 integrins and that binding maps to the plexin-semaphorinintegrin (PSI) domain present at the apex of inactive, bent, ␣v␤3-integrin structures. Pathogenic hantaviruses [New York-1 virus (NY-1V) and Hantaan virus (HTNV)] bind immobilized ␤3 polypeptides containing the PSI domain, and human (but not murine) ␤3 polypeptides inhibit hantavirus infectivity. Substitution of human ␤3 residues 1-39 for murine ␤3 residues directed pathogenic hantavirus infection of nonpermissive CHO cells expressing chimeric ␣v␤3 receptors. Mutation of murine ␤3 Asn-39 to Asp-39 present in human ␤3 homologues (N39D) permitted hantavirus infection of cells and specified PSI domain residue interactions with pathogenic hantaviruses. In addition, cell-surface expression of ␣v␤3 locked in an inactive bent conformation conferred hantavirus infectivity of CHO cells. Our findings indicate that hantaviruses bind to a unique domain exposed on inactive integrins and, together with prior findings, suggest that this interaction restricts ␣v␤3 functions that regulate vascular permeability. Our findings suggest mechanisms for viruses to direct hemorrhagic or vascular diseases and provide a distinct target for modulating ␣v␤3-integrin functions.pathogenesis ͉ receptor P athogenic hantaviruses cause two human diseases with striking changes in vascular permeability: hemorrhagic fever with renal syndrome and hantavirus pulmonary syndrome (1-3). Hantaviruses infect endothelial cells throughout the body, and pulmonary or renal manifestations may accompany either disease (1-3). Unlike some hemorrhagic viruses, hantaviruses do not lyse endothelial cells, and alternate processes are required to explain vascular changes that direct pathogenesis. There are no therapeutic approaches for hantavirus diseases, and the cause of acute thrombocytopenia, edema, or vascular hemorrhage after hantavirus infections have not been defined.Hemorrhagic diseases are caused by permeability changes within the vascular endothelium. ␤3 integrins on platelets (␣ IIb ␤3) and endothelial cells (␣v␤3) regulate vascular permeability (4-8), and several human hemorrhagic diseases result from dysregulating ␤3-integrin functions (9-14). Glanzmann's disease is a human genetic ␤3-integrin-specific bleeding disorder hallmarked by thrombocytopenia and microvascular hemorrhage (9). At least three autoimmune hemorrhagic diseases are caused by Ab responses to N-terminal residues of ␤3-subunits or to an atypical ␤3-integrin ligand (10-14). Among these diseases, Goodpasture's syndrome is hallmarked by lethal pulmonary edema, hemorrhage, and glomerulonephritis (11,13,14). Pathogenic hantaviruses also dysregulate ␤3-integ...

The C-Terminal 42 Residues of the Tula Virus Gn Protein Regulate Interferon Induction

“…␤ 3 Receptors on platelets and endothelial cells regulate fluid barrier functions of the vasculature as well as permeability induced by vascular endothelial growth factor (VEGF) (8,9,16). Pathogenic hantaviruses dysregulate normal ␣ v ␤ 3 integrin functions through interactions with inactive conformations of the integrin and dramatically enhance endothelial cell permeability in response to VEGF (9,33,39). These responses clearly differentiate pathogenic hantaviruses from nonpathogenic PHV and TULV (9,10) and are likely to contribute, at least in part, to hantavirus pathogenesis.…”

“…Integrin receptor regulation further distinguishes pathogenic from nonpathogenic hantaviruses and is associated with increased vascular permeability (9,10,16,39). Only pathogenic hantaviruses use ␣ v ␤ 3 integrin endothelial cell receptors, while TULV and PHV use ␣ 5 ␤ 1 integrins for cell entry (7,11,39).…”

“…Integrin receptor regulation further distinguishes pathogenic from nonpathogenic hantaviruses and is associated with increased vascular permeability (9,10,16,39). Only pathogenic hantaviruses use ␣ v ␤ 3 integrin endothelial cell receptors, while TULV and PHV use ␣ 5 ␤ 1 integrins for cell entry (7,11,39). ␤ 3 Receptors on platelets and endothelial cells regulate fluid barrier functions of the vasculature as well as permeability induced by vascular endothelial growth factor (VEGF) (8,9,16).…”

Hantaviruses Direct Endothelial Cell Permeability by Sensitizing Cells to the Vascular Permeability Factor VEGF, while Angiopoietin 1 and Sphingosine 1-Phosphate Inhibit Hantavirus-Directed Permeability

“…Interestingly, pathogenic, but not nonpathogenic, hantaviruses re-portedly bind and dysregulate the function of ␣v␤3 integrins on human endothelial cells (19)(20)(21). HFRS and HPS causing hantaviruses block ␣v␤3-directed endothelial cell migration 2 to 4 days after infection and thereby inhibit ␣v␤3 integrin function days after viral adsorption (19)(20)(21)54). A mechanism for hantavirus inhibition of ␣v␤3 function is provided by findings demonstrating that pathogenic hantaviruses interact with plexin-semaphorin-integrin domains present at the apex of bent, inactive conformations of ␣v␤3 (54,73).…”

Pathogenic Old World Hantaviruses Infect Renal Glomerular and Tubular Cells and Induce Disassembling of Cell-to-Cell Contacts

“…The number of viable cells was determined by measuring the amount of ATP using CellTiter-Glo luminescent cell viability assay (Promega, Mannheim, Germany). human umbilical vein endothelial cells, or hamster tracheal epithelial cells were used to identify integrin as receptor for Old and New World hantaviruses (20,22,43,59,61). We analyzed human renal cell types for their susceptibility to hantavirus infection by the detection of the hantaviral receptor integrin ␣ V ␤ 3 : primary human renal tubular epithelial cells (HREpC), glomerular endothelial cells (HRGEnC), and podocytes.…”