Aptamer Blocking Strategy Inhibits SARS-CoV-2 Virus Infection

Area of Science:

• Biochemistry
• Molecular Biology
• Virology

Background:

• The COVID-19 pandemic, caused by SARS-CoV-2, poses a significant global health threat.
• Inhibiting the interaction between the SARS-CoV-2 S-receptor binding domain (S_RBD) and the human ACE2 receptor is a key therapeutic strategy.
• Existing neutralizing antibodies face challenges such as antibody-dependent enhancement (ADE) and large size, hindering intranasal delivery.

Purpose of the Study:

• To develop an aptamer-based strategy to block SARS-CoV-2 infection by targeting the S_RBD-ACE2 interaction.
• To engineer a stable and highly effective aptamer for potential therapeutic applications against SARS-CoV-2.

Main Methods:

• Aptamer selection and screening against the SARS-CoV-2 S_RBD.
• Molecular docking to identify aptamers that bind to the ACE2 interaction site.
• Engineering of a circular bivalent aptamer (cb-CoV2-6C3) for enhanced stability and affinity.
• In vitro testing of aptamer efficacy against authentic SARS-CoV-2 virus.

Main Results:

• Aptamer CoV2-6 was identified, capable of preventing, competing with, and substituting ACE2 binding to S_RBD.
• The engineered circular bivalent aptamer cb-CoV2-6C3 demonstrated improved stability in serum (>12 hours) and room temperature storage (>14 days).
• cb-CoV2-6C3 exhibits high affinity binding to S_RBD (K_d =0.13 nM) and potent inhibition of authentic SARS-CoV-2 virus (IC₅₀ =0.42 nM).

Conclusions:

• Aptamer-based blocking is a viable strategy to inhibit SARS-CoV-2 infection, overcoming limitations of antibody therapies.
• The engineered aptamer cb-CoV2-6C3 shows significant potential as a therapeutic agent for COVID-19 due to its stability, high affinity, and potent antiviral activity.