Propofol directly binds to and inhibits TLR7

Area of Science:

• Immunology
• Pharmacology
• Virology

Background:

• Sedatives and anesthetics can impact immune function.
• Toll-like receptor 7 (TLR7) is crucial for antiviral responses, recognizing viruses like SARS-CoV-2.
• Impaired TLR7 function is linked to severe COVID-19 outcomes.

Purpose of the Study:

• To investigate whether propofol, an intravenous sedative/anesthetic, affects TLR7 immune function.
• To understand the mechanism by which propofol might modulate TLR7 signaling.

Main Methods:

• Reporter assays to measure TLR7 activation.
• Stimulation of bone marrow-derived dendritic cells with a TLR7 agonist (R837) in the presence of propofol.
• Murine lung slice and in vivo experiments to assess IFN-β production.
• Analysis of propofol's direct binding to TLR7 and its interaction with MyD88.

Main Results:

• Propofol significantly attenuated TLR7 activation and the production of inflammatory cytokines (TNF-α, IL-1β, IL-6, IL-10) and interferon-beta (IFN-β).
• Propofol reduced IFN-β expression in murine lung slices and in vivo.
• Propofol was shown to directly bind TLR7, hindering its association with MyD88.
• A derivative of propofol indicated the hydroxyl group is essential for this interaction.

Conclusions:

• Propofol inhibits TLR7-mediated immune responses, potentially impacting antiviral defenses.
• The anesthetic propofol directly interferes with TLR7 signaling by preventing MyD88 binding.
• Understanding propofol's immunomodulatory effects is critical for patient care, especially during viral infections.