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ORIGINAL RESEARCH article

Front. Microbiol.
Sec. Virology
Volume 16 - 2025 | doi: 10.3389/fmicb.2025.1498955

Respiratory syncytial virus fuses with plasma membrane to infect primary cultures of bronchial epithelial cells

Provisionally accepted
Christian Cadena Christian Cadena 1,2*Marcio De Avila-Arias Marcio De Avila-Arias 2,3Leidy Hurtado Leidy Hurtado 2Heather Costello Heather Costello 4Walter Martinez Walter Martinez 5Gigliola Macchia Gigliola Macchia 2Wendy Rosales Wendy Rosales 1Gerardo Valencia Gerardo Valencia 2Pedro Villalba Pedro Villalba 2Meisam Kararoudi Meisam Kararoudi 4Mark Peeples Mark Peeples 4Homero G. San-Juan-Vergara. Homero G. San-Juan-Vergara. 2*
  • 1 Universidad Libre de Colombia Seccional Barranquilla, Barranquilla, Atlántico, Colombia
  • 2 Universidad del Norte, Colombia, Barranquilla, Colombia
  • 3 Intitut Pasteur, Université Paris Cité, Paris, Ile-de-France, France
  • 4 Nationwide Children's Hospital, Columbus, Ohio, United States
  • 5 Universidad Metropolitana, Barranquilla, Colombia

The final, formatted version of the article will be published soon.

    Respiratory syncytial virus (RSV) is a common cause of bronchiolitis in children under the age of five. RSV infection proceeds by fusion of the viral envelope with the target cell membrane, but it is unclear whether fusion occurs with plasma or endosomal membranes. Entry and/or infection was studied in undifferentiated primary cultures of human bronchial epithelial cells. Synchronization of viral entry or infection was achieved by attaching the virus to the plasma membrane at temperatures of 4°C or 22°C. Cells in which entry events had occurred were identified by the enzymatic action of beta-lactamase M (BlaM) fused to the RSV P protein (BlaM-P) carried by rgRSV virions. BlaM cleaves the beta-lactam ring of CCF2 loaded into the cells, disrupting FRET and allowing blue light to be emitted. Green fluorescent protein (GFP) expression, encoded by rgRSV genome, was used to identify infected cells. We found that adsorption of RSV at 4°C favors entry via endocytosis, whereas binding of the virus to the membrane at 22°C favors RSV entry via the plasma membrane. The induction of endocytosis by synchronization at 4°C is an artifact. In addition, we found that all drugs that interfered with RSV infection reduced cell membrane deformations such as filopodia and lamellipodia, suggesting a mechanism by which they may interfere with RSV fusion with the cell membrane. In conclusion, RSV can fuse its envelope directly to the plasma membrane.

    Keywords: Respiratory sycytial virus, synchronization, plasma membrane, Viral entry, Endocytosis

    Received: 19 Sep 2024; Accepted: 27 Jan 2025.

    Copyright: © 2025 Cadena, De Avila-Arias, Hurtado, Costello, Martinez, Macchia, Rosales, Valencia, Villalba, Kararoudi, Peeples and San-Juan-Vergara.. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence:
    Christian Cadena, Universidad Libre de Colombia Seccional Barranquilla, Barranquilla, Atlántico, Colombia
    Homero G. San-Juan-Vergara., Universidad del Norte, Colombia, Barranquilla, Colombia

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