The monomeric but not homotrimeric spike protein of SARS-CoV-2 activates TLR4 signaling.

ABSTRACT:

Background

Recent findings indicate that hyperinflammatory responses to SARS-CoV-2 are major contributors to the severity and fatality of COVID-19. Pattern recognition receptors, particularly Toll-like receptors 2 (TLR2) and 4 (TLR4), have been implicated in detecting SARS-CoV-2 proteins, especially the spike protein. However, the role of viral structural components in triggering innate immune responses remains poorly understood.

Methods and results

HEK293 reporter cells, engineered to stably express TLR2 or TLR4, and THP-1 differentiated macrophages were exposed to various spike protein components and SARS-CoV-2 variants. Protein levels of cytokines were detected by ELISA and mRNA expression was evaluated by quantitative real-time RT-PCR. We demonstrate that the S1 subunit

SUBMITTER: Lubow C 

PROVIDER: S-EPMC12185570 | biostudies-literature | 2025 Jun

REPOSITORIES: biostudies-literature