Related Experiment Video
Updated: Jul 10, 2026
A High-throughput Cre-Lox Activated Viral Membrane Fusion Assay to Identify Inhibitors of HIV-1 Viral Membrane Fusion
Published on: August 14, 2018
Identification and evaluation of a highly effective fusion inhibitor for human metapneumovirus
Céline Deffrasnes1, Marie-Eve Hamelin, Gregory A Prince
1Research Center in Infectious Diseases of the Centre Hospitalier Universitaire de Québec and Laval University, Quebec City, Quebec, Canada.
Abstract:
Human metapneumovirus (hMPV) can cause acute upper and lower respiratory tract infections that are particularly severe in young children, elderly subjects, and immunocompromised patients. To date, no treatments or vaccines are available for hMPV infections. Our objective was to assess the inhibitory potential of several peptides derived from the heptad repeat A and B (HRA and HRB) domains of the hMPV fusion protein. Nine candidate peptides were expressed in Escherichia coli or obtained synthetically and tested in vitro and in an animal model. Excellent in vitro inhibition of an hMPV strain of the A1 subgroup was obtained with five peptides, with 50% inhibitory concentrations ranging from 1.4 nM to 3.3 microM. One peptide, HRA2, displayed very potent activity against all four hMPV subgroups. It was also moderately active against human respiratory syncytial virus (strain A2) but displayed no activity against human parainfluenza virus type 3. BALB/c mice that received the HRA2 peptide and a lethal hMPV intranasal challenge simultaneously were completely protected from clinical symptoms and mortality. On day 5 postinfection, HRA2-treated mice had undetectable lung viral loads which were significantly less than those of untreated mice (3 x 10(4) 50% tissue culture infective doses/lung). Pulmonary inflammation, levels of proinflammatory cytokines/chemokines (RANTES, gamma interferon, and monocyte chemoattractant protein 1) and airway obstruction were also significantly decreased in HRA2-treated mice. The results of this study demonstrate that potent antivirals can be derived from the hMPV fusion protein HR domains. Moreover, hMPV, compared to other paramyxoviruses and to the human immunodeficiency virus, seems to be more susceptible to HRA- than HRB-derived peptides.
Insights
New peptides derived from the human metapneumovirus (hMPV) fusion protein show potent antiviral activity. One peptide, HRA2, completely protected mice from hMPV infection, demonstrating potential for new hMPV treatments.
Area of Science:
- Virology
- Drug Discovery
- Immunology
Background:
- Human metapneumovirus (hMPV) causes severe respiratory infections, particularly in vulnerable populations.
- Currently, no effective treatments or vaccines exist for hMPV.
- The hMPV fusion (F) protein is a key target for antiviral development.
Purpose of the Study:
- To evaluate the antiviral potential of peptides derived from the heptad repeat A (HRA) and B (HRB) domains of the hMPV fusion protein.
- To identify specific peptides with potent inhibitory activity against hMPV.
- To assess the efficacy of promising peptides in a preclinical animal model.
Main Methods:
- Nine candidate peptides were synthesized or expressed.
- In vitro assays were used to determine 50% inhibitory concentrations (IC50) against hMPV subgroups.
- Peptide efficacy was evaluated in a BALB/c mouse model challenged with hMPV, assessing clinical symptoms, mortality, viral load, and pulmonary inflammation.
Main Results:
- Five peptides demonstrated excellent in vitro inhibition of hMPV A1 subgroup, with IC50 values from 1.4 nM to 3.3 µM.
- The peptide HRA2 showed potent activity against all four hMPV subgroups and moderate activity against human respiratory syncytial virus (RSV).
- HRA2 completely protected mice from hMPV-induced mortality and clinical symptoms, significantly reducing viral load, inflammation, and airway obstruction.
Conclusions:
- Peptides derived from the hMPV fusion protein's HR domains represent a promising source for developing novel antiviral therapies.
- HRA2 is a particularly potent candidate, demonstrating broad-spectrum activity against hMPV subgroups and significant efficacy in vivo.
- The findings suggest that hMPV may be more susceptible to HRA-derived peptides than HRB-derived peptides.
