Inhibition of Human Metapneumovirus Binding to Heparan Sulfate Blocks Infection in Human Lung Cells and Airway Tissues

Abstract

Human metapneumovirus (HMPV), a recently discovered paramyxovirus, infects nearly 100% of the world population and causes severe respiratory disease in infants, the elderly, and immunocompromised patients. We previously showed that HMPV binds heparan sulfate proteoglycans (HSPGs) and that HMPV binding requires only the viral fusion (F) protein. To characterize the features of this interaction critical for HMPV binding and the role of this interaction in infection in relevant models, we utilized sulfated polysaccharides, heparan sulfate mimetics, and occluding compounds. Iota-carrageenan demonstrated potent anti-HMPV activity by inhibiting binding to lung cells mediated by the F protein. Furthermore, analysis of a minilibrary of variably sulfated derivatives of Escherichia coli K5 polysaccharide mimicking the HS structure revealed that the highly O-sulfated K5 polysaccharides inhibited HMPV infection, identifying a potential feature of HS critical for HMPV binding. The peptide dendrimer SB105-A10, which binds HS, reduced binding and infection in an F-dependent manner, suggesting that occlusion of HS at the target cell surface is sufficient to prevent infection. HMPV infection was also inhibited by these compounds during apical infection of polarized airway tissues, suggesting that these interactions take place during HMPV infection in a physiologically relevant model. These results reveal key features of the interaction between HMPV and HS, supporting the hypothesis that apical HS in the airway serves as a binding factor during infection, and HS modulating compounds may serve as a platform for potential antiviral development. IMPORTANCE Human metapneumovirus (HMPV) is a paramyxovirus that causes respiratory disease worldwide. It has been previously shown that HMPV requires binding to heparan sulfate on the surfaces of target cells for attachment and infection.In this study, we characterize the key features of this binding interaction using heparan sulfate mimetics, identify an important sulfate modification, and demonstrate that these interactions occur at the apical surface of polarized airway tissues. These findings provide insights into the initial binding step of HMPV infection that has potential for antiviral development.A cute viral respiratory tract infection is the most frequently observed illness in humans worldwide (1). Human metapneumovirus (HMPV), an enveloped, negative-sense, singlestranded RNA virus in the Paramyxoviridae family, is a common cause of both upper and lower respiratory tract infections (2-4). First identified in 2001 in the Netherlands, HMPV is now known to be the cause of respiratory infections in humans since at least 1958 (2). Nearly every person is exposed to HMPV in the first decade of life; seroconversion occurs on average by the age of 5 years, and nearly 100% of individuals test seropositive for antibody reactivity to HMPV antigens by the age of 10 (5). In children, HMPV infection is the second most common cause of hospitalization due to respiratory infection after the ...

Synthetic sulfonated derivatives of poly(allylamine hydrochloride) as inhibitors of human metapneumovirus

“…While some previous reports suggest inhibition of early stages of viral replication by carrageenans [19], we were not able to replicate these results. It is, however, possible that the mechanism of action may very depending on the origin of these natural polymers [15,20,21,26].…”

“…hMPV F protein utilizes heparan sulfate (HS), a negatively charged glycosaminoglycan (GAG) present on the cellular membrane, as an attachment factor [11]. Previous studies have shown that natural polysaccharides containing sulfonate groups efficiently inhibit infections caused by viruses employing HS during cell entry [12][13][14][15][16][17][18][19] and it was proposed that carrageenans inhibit the attachment of the hMPV to HS by interacting with the F protein [19]. It is, however, worth to mention that replication of some HS independent viruses is also hampered in the presence of these polymers [20][21][22][23].…”

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