ABSTRACT
Hydroxychloroquine (HCQ) has been proposed in the treatment of SARS-coronavirus 2 (SARS-CoV-2) infection, albeit with much controversy. In vitro, HCQ effectively inhibits viral entry, but its use in the clinic has been hampered by conflicting results. A better understanding of HCQ’s mechanism of actions in vitro is needed to resolve these conflicts. Recently, anesthetics were shown to disrupt ordered monosialotetrahexosylganglioside1 (GM1) lipid rafts. These same lipid rafts recruit the SARS-CoV-2 surface receptor angiotensin converting enzyme 2 (ACE2) to an endocytic entry point, away from phosphatidylinositol 4,5 bisphosphate (PIP2) domains. Here we employed super resolution imaging of cultured mammalian cells to show HCQ directly perturbs GM1 lipid rafts and inhibits the ability of ACE2 receptor to associate with the endocytic pathway. HCQ also disrupts PIP2 domains and their ability to cluster and sequester ACE2. Similarly, the antibiotic erythromycin inhibits viral entry and both HCQ and erythromycin decrease the antimicrobial host defense peptide amyloid beta in cultured cells. We conclude HCQ is an anesthetic-like compound that disrupts GM1 lipid rafts similar to anesthetics. The disruption likely decreases viral clustering at both endocytic and putative PIP2 entry points.
KEY POINTS Question: What is the molecular basis for antiviral activity of hydroxychloroquine?
Findings: Hydroxychloroquine disrupt lipid rafts similar to general anesthetics.
Meaning: Since lipids cluster ACE2 and facilitate viral entry, hydroxychloroquine appears to inhibit viral entry by disrupting the lipid clustering of the SARS-CoV2 receptor.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
Conflicts of Interests/Financial Disclosures: NONE
Support: This work was supported by the National Institutes of Health with an R01 to S.B.H. (R01NS112534) and the US Department of Defense with an Accelerating Innovation in Military Medicine to S.B.H. (W81XWH1810782). The funding supported all the salaries and research expenses for these studies. The Iris and Junming Le Foundation purchase a super-resolution microscope, making this study possible.
Reformatted the abstract added references supporting erythromycin as an antiviral. Updated the discussion.