Can SARS-CoV-2 Virus Use Multiple Receptors to Enter Host Cells?

Area of Science:

• Virology
• Immunology
• Cell Biology

Background:

• Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) causes COVID-19, a global health threat.
• The SARS-CoV-2 spike (S) protein typically uses ACE2 for host cell entry.
• Viral entry into ACE2-negative cells suggests alternative receptor usage.

Purpose of the Study:

• Investigate alternative SARS-CoV-2 S protein interactions beyond ACE2.
• Identify novel host cell receptors involved in viral entry and pathogenesis.
• Explore potential therapeutic targets for COVID-19.

Main Methods:

• Review of existing studies on SARS-CoV-2 S protein interactions.
• Analysis of reported viral tropism in cells lacking ACE2.
• Examination of S protein interactions with innate immune receptors and non-immune receptors.

Main Results:

• SARS-CoV-2 S protein interacts with C-lectin type receptors (CLR), toll-like receptors (TLR), neuropilin-1 (NRP1), and glucose regulated protein 78 (GRP78).
• Carbohydrate recognition on the S protein may mediate receptor-dependent entry and inflammation.
• These alternative pathways may facilitate systemic infection independently of ACE2.

Conclusions:

• SARS-CoV-2 utilizes multiple host cell receptors for entry, not solely ACE2.
• Targeting receptors like TLRs and CLRs could enhance antiviral immunity and viral clearance.
• These findings suggest new therapeutic strategies against COVID-19 by targeting alternative receptors.