Journal of Glycobiology
Open Access

Role of Glycans in Viral Pathogenesis and their Potential as Therapeutic Targets

Joao Maria^{* *}Correspondence: Joao Maria, Department of Medicine, University of Porto, Porto, Portugal, Email:

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Description

Glycans, the complex sugar molecules that attach to proteins and lipids, are key players in many biological processes, including viral infection. These glycan structures are critical to the viral life cycle, facilitating the ability of viruses to infect host cells and spread within the body. Given their central role in viral pathogenesis, glycans are emerging as promising therapeutic targets for combating viral diseases. This article explores how glycans contribute to viral infections and how targeting glycan interactions holds potential for developing new antiviral strategies.

Glycans and viral entry

A key step in viral infection is the attachment and entry of the virus into host cells. Many viruses rely on glycan-binding proteins (lectins) to interact with specific glycan structures present on the surface of host cells. For example, the influenza virus uses Hemagglutinin (HA) to bind to sialic acid-containing glycans on epithelial cells of the respiratory tract. Similarly, the Human Immunodeficiency Virus (HIV) binds to CD4 receptors and uses glycans to enhance its interaction with the host cell. Once the viral particle attaches to the host cell via these glycan-protein interactions, the virus can enter the cell and begin replication. Other viruses, like coronaviruses (including Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), also exploit host cell glycans for efficient binding to receptors, such as the Angiotensin-Converting Enzyme 2 (ACE2) receptor. The viral Spike protein (S-protein) of SARS-CoV-2 contains glycan moieties that play a role in its affinity for host cell receptors, making glycan-protein interactions a critical component in viral entry.

Glycan-mediated immune evasion

Viruses can also use glycans to evade the host immune system. Sialic acid, a sugar commonly found on the surface of both host cells and viruses, can mask viral antigens, preventing recognition by the immune system. For instance, influenza viruses are often coated with sialic acid residues, which help them avoid detection by the host immune system. Similarly, the HIV can modify its surface glycoproteins to incorporate host-like glycans, allowing it to evade immune detection and prolong infection.

Glycans as therapeutic targets

Because glycans play such a central role in viral pathogenesis, they are being explored as potential targets for antiviral therapies. There are several strategies for targeting glycans in the context of viral infection:

Inhibition of glycan-protein interactions:

One approach is to disrupt the interaction between viruses and host cell glycans. For example, blocking the binding of viral glycoproteins to host cell receptors could prevent viral entry. Sialic acid analogs or glycomimetics that mimic the structure of natural glycans are being developed to interfere with these interactions. By competitively binding to viral receptors, these molecules can prevent viral attachment to host cells.

Glycan-binding protein inhibitors: Viruses often rely on glycanbinding proteins (lectins) to facilitate their entry into cells. Inhibiting these lectins can prevent viral attachment. Lectin inhibitors are being investigated as antiviral agents to block the interaction between viral proteins and host glycans. For example, concanavalin A has shown promise in inhibiting HIV entry by targeting its glycan-binding proteins.

Targeting viral glycosylation: Many viruses modify their own glycoproteins through glycosylation to enhance infectivity or immune evasion. Inhibiting the glycosylation of viral proteins could reduce their ability to bind to host cell receptors and evade the immune system. Drugs that inhibit viral glycosyltransferases or other enzymes involved in glycosylation are being explored for their antiviral potential.

Vaccine development: Glycans are also important targets for vaccine development. For example, designing vaccines that target specific glycan structures on viral surface proteins can stimulate the immune system to recognize and neutralize the virus. The use of glycan-based vaccines is being investigated for various viruses, including influenza and HIV.

Conclusion

Glycans are essential to viral pathogenesis, playing a critical role in viral entry, immune evasion, and replication. As a result, targeting glycan-protein interactions presents a potential strategy for the development of antiviral therapies. Research into glycan-based treatments, such as glycomimetics, lectin inhibitors, and viral glycosylation inhibitors, is advancing rapidly, offering hope for new therapeutic options to combat viral diseases. With continued research, glycans may become base in the fight against viral infections, providing a novel avenue for antiviral drug discovery and vaccine development.