ACE2-PNA conjugates exploit viral endocytosis for targeted intracellular delivery and exhibit dual antiviral efficacy against SARS-CoV-2

Nanobodies targeting SARS-CoV-2 papain-like protease exert dual antiviral and anti-inflammatory effects

It is demonstrated that nanobodies targeting the PLpro/ISG15 interface can achieve synergistic antiviral and immunomodulatory effects, providing a proof-of-concept for a novel therapeutic approach to combat SARS-CoV-2 and potentially other emerging coronaviruses.

Targeted degradation of Influenza a virus nucleoprotein via aptamer-based PROTACs for antiviral therapy

These findings provide the first evidence that NP-targeted PROTAC degrader exhibits therapeutic effects, proposing a novel therapeutic strategy for IAV.

Extracellular Vesicles as Molecular Regulators of Viral Infection: Implications for COVID-19 and Future Viral Pandemics

Coronavirus disease 2019 (COVID-19), caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), exposed critical gaps in global preparedness for rapidly evolving viral pandemics. Though current antiviral treatments have shown some efficacy in managing COVID-19, substantial limitations, such as inefficient targeted drug delivery, aberrant host immune responses, and inadequate preparedness for future viral pandemics, were also evident. These challenges underscore the urgent need for target-specific, precise and efficient therapeutic strategies to modulate viral entry and immune dysregulation. Extracellular vesicles (EVs), cell-released cargo-carrying nanoscale vesicles, can both facilitate and inhibit viral infection depending on their cargo composition. Thus, endogenous EVs can promote or inhibit COVID-19 pathogenesis by modulating critical pathways, including angiotensin-converting enzyme 2 (ACE2)-mediated viral entry, transmembrane protease serine 2 (TMPRSS2)- dependent spike protein activation, nuclear factor kappa B (NF-κB)-driven inflammatory signaling, and NLRP3 inflammasome activation. In contrast, engineered EVs, such as ACE2-expressing EVs, mesenchymal stem cell-derived EVs and microRNA-enriched EVs, have therapeutic potential as they can facilitate antiviral defense through immune modulation, viral neutralization and suppression of cytokine storm. Moreover, EV-associated nucleic acids, proteins and lipids can act as biomarkers for disease detection and severity stratification. A deeper understanding of EV-virus mechanistic insights can enhance preparedness for similar viral diseases. In this review, we provide a comprehensive analysis of the molecular mechanisms underlying EV-virus interactions highlighting the therapeutic and diagnostic potential of EVs in tackling COVID-19 and future viral pandemics.

Computational design of immunogenic peptide–ligand conjugates for targeted therapy against Nipah virus infection

Introduction Nipah virus (NiV) poses a major risk to global public health due to its high infectivity and associated mortality rates. Currently, no licensed vaccines or antiviral medications are available for NiV infection, leaving clinical management limited to supportive care. The viral receptor glycoprotein responsible for binding NiV to host cell receptors (ephrin-B2/B3) represents an ideal therapeutic target. This study proposes a novel peptide-ligand conjugate (PLC) immunotherapeutic approach that exploits pre-existing immune responses in NiV-endemic populations to selectively target and eliminate infected cells. Methods We employed biomolecular modeling (in silico) to establish binding affinities and perform docking studies using a compound library obtained from the MolProphet database. A non-cleavable oxime linker was selected to enhance physical stability and ensure robust conjugation between ligand and peptide components. The peptide was engineered to contain immunogenic minimal epitope regions derived from measles, mumps, and rubella vaccines, selected based on their high immunization rates and long-lived memory responses in individuals residing in NiV-endemic areas. Results The PLC design demonstrated selective binding capacity to a transmembrane protein present on NiV-infected cells. The oxime linker provided enhanced stability, and the peptide epitope design successfully incorporated regions associated with established long-term immunity. Discussion This PLC system represents a promising framework for antiviral therapeutic development by harnessing pre-existing immune recognition to promote selective clearance of NiV-infected cells. The findings highlight critical structural components and functional roles of PLCs in therapeutic development, including drug target screening and rational design strategies for enhancing targeting specificity and molecular stability. Future work should focus on experimental validation of the computational predictions and in vitro/in vivo efficacy studies.

Multivalent Anti-ACE2 Nanobodies Confer Broad Pan-Sarbecovirus Protection

A neuraminidase-targeting nanobody as a therapeutic candidate against influenza A and B viruses

ABSTRACT Influenza viruses continue to pose a significant threat to human and animal health. However, the limited number of licensed antivirals is increasingly compromised by drug resistance driven by high mutation rates. This highlights the urgent need for broad-spectrum therapeutics with novel mechanisms of action. Nanobodies, a new generation of antibody drugs, have great potential in the treatment of influenza virus infections. Neuraminidase (NA) mediates the sialic acid cleavage required for viral release, and its genetic drift is generally slower than that of hemagglutinin (HA) in influenza viruses, making it an attractive target for broad-spectrum antiviral and vaccine development. To construct a phage display nanobody library targeting NA, an alpaca was immunized with the NA protein of the H9N2 influenza virus. A specific nanobody, designated F4, was subsequently screened from the immune library. The nanobody was engineered into an Fc-fused nanobody, F4-Fc, which exhibited inhibitory activity against multiple influenza A and B viruses in vitro and provided robust prophylactic and therapeutic protection against influenza A and influenza B virus infections in vivo. Mechanistically, F4-Fc inhibits NA enzymatic activity and mediates antibody-dependent cellular cytotoxicity. In conclusion, F4-Fc demonstrates prophylactic and therapeutic efficacy against influenza A and B viruses, representing a promising antiviral drug candidate for influenza virus infection. IMPORTANCE Influenza viruses seriously threaten human and animal health, and drugs are crucial for controlling influenza outbreaks. However, the limited variety of existing anti-influenza virus medicines and the high mutation rate of the virus have led to the continuous emergence of drug-resistant strains. Neuraminidase (NA) is a critical surface glycoprotein that exhibits slower antigenic drift than hemagglutinin (HA), making it an attractive target for cross-protective antiviral development. However, broadly active NA-targeting nanobodies, particularly those effective against both influenza A and B viruses, remain limited. Here, we constructed an Fc-fused F4 nanobody (F4-Fc) targeting neuraminidases from multiple influenza A and B viruses and demonstrated its antiviral efficacy in vitro and protective activity in vivo, highlighting its potential as a promising strategy for the prevention and treatment of influenza virus infection. Influenza viruses seriously threaten human and animal health, and drugs are crucial for controlling influenza outbreaks. However, the limited variety of existing anti-influenza virus medicines and the high mutation rate of the virus have led to the continuous emergence of drug-resistant strains. Neuraminidase (NA) is a critical surface glycoprotein that exhibits slower antigenic drift than hemagglutinin (HA), making it an attractive target for cross-protective antiviral development. However, broadly active NA-targeting nanobodies, particularly those effective against both influenza A and B viruses, remain limited. Here, we constructed an Fc-fused F4 nanobody (F4-Fc) targeting neuraminidases from multiple influenza A and B viruses and demonstrated its antiviral efficacy in vitro and protective activity in vivo, highlighting its potential as a promising strategy for the prevention and treatment of influenza virus infection.