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Cyclophilin A-mediated mitigation of coronavirus SARS-CoV-2

Simranjeet Singh Sekhon1, Woo-Ri Shin1, Sang Yong Kim2

  • 1Department of Microbiology Chungbuk National University Seowon-Gu Cheongju South Korea.

Bioengineering & Translational Medicine
|January 30, 2023
PubMed

Insights

Human cyclophilin A (hCypA) binds strongly to SARS-CoV-2, blocking viral entry into host cells. This interaction remains effective against variants, suggesting hCypA as a potential antiviral target for COVID-19 therapy.

Area of Science:

  • Virology
  • Molecular Biology
  • Biochemistry

Background:

  • Human cyclophilin A (hCypA) is implicated in the replication of various coronaviruses (CoVs).
  • Cyclosporine A inhibitors demonstrate efficacy in suppressing CoVs.
  • Emerging SARS-CoV-2 variants raise concerns about potential alterations in spike protein binding to ACE2, impacting COVID-19 severity.

Purpose of the Study:

  • To investigate the interaction between human cyclophilin A (hCypA) and the SARS-CoV-2 spike protein's receptor-binding domain (RBD).
  • To elucidate the mechanism by which hCypA affects SARS-CoV-2 entry into host cells.
  • To assess the potential of hCypA as an antiviral therapeutic target against SARS-CoV-2 and its variants.

Main Methods:

  • Far-western blotting and surface plasmon resonance (SPR) were employed to determine the binding affinity between hCypA and the SARS-CoV-2 RBD.
  • Three-dimensional structural analysis was utilized to visualize the molecular interaction at the protein interface.
  • Molecular Interaction Lateral Flow (MILF) strip assays were performed to confirm the blocking mechanism and assess variant interactions.

Main Results:

  • hCypA exhibits strong binding to the SARS-CoV-2 RBD with a binding affinity of 6.85 × 10-8 M.
  • hCypA physically blocks key residues on the RBD interface, inhibiting its binding to the ACE2 receptor.
  • This interaction effectively suppresses viral entry into host cells, a critical step for CoV infection.
  • Mutations in the RBD of emerging SARS-CoV-2 variants had a negligible impact on hCypA binding.
  • hCypA demonstrated a neutralizing effect by blocking both wild-type and variant RBDs from binding to ACE2.

Conclusions:

  • hCypA plays a crucial role in regulating viral entry by inhibiting the interaction between the SARS-CoV-2 RBD and the ACE2 receptor.
  • The consistent binding of hCypA to RBD variants suggests its potential as a broad-spectrum antiviral strategy against SARS-CoV-2.
  • hCypA represents a promising therapeutic target for developing novel antiviral treatments for COVID-19 and future coronavirus infections.
Keywords:
COVID‐19 variantscoronaviruscyclophilinspike protein receptor‐binding domainsurface plasmon resonance

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