Abstract 10611: Inhibition of Sars-cov-2 Viral Channel Activity Using FDA-Approved Channel Modulators Independent of Variants

Abstract

Introduction: SARS-CoV-2 has undergone mutations, yielding clinically relevant variants such as Delta and Omicron. Early detection of virus and effective therapeutic treatment independent of variants help control virus spread. Hypothesis: We hypothesized that in the genome of SARS-CoV-2 two highly conserved viroporins Orf3a and E channels directly related to virus replication may be explored as a target for detection and inhibition of viral replication independent of variants using FDA-approved ion channel modulators. Methods: A combination of a fluorescence potassium ion assay with three channel modulators (4-aminopyridine, emodin-Orf3a channel blocker, gliclazide-E channel blocker) in a 96-well plate format was developed to detect SARS-CoV-2 Orf3a/E channel activity. We subtracted the fluorescence signals in the absence and presence of emodin/gliclazide to detect Orf3a and E channel activity. Two FDA-approved drugs, amantadine (an antiviral) and amitriptyline (an antidepressant) that are also ion channel blockers, were used to test whether they can inhibit Orf3a/E channel activity in isolated virus (UV inactivated) and in nasal swab samples from Covid-19 patients. Twenty-one (21) Delta and thirty (30) Omicron nasal swab samples were used. Variants were confirmed by PCR sequencing. Results: Orf3a and E form non-voltage-gated ion channels that are highly conserved in SARS-CoV-2 variants. In UV-inactivated SARS-CoV-2 Alpha, Beta, and Delta variants, significant channel activity of Orf3a/E was detected based on an increase in fluorescence induced by 4-aminopyridine, and this increase in fluorescence was inhibited by emodin and gliclazide (IC 50 = 0.42mM). Amantadine and amitriptyline can inhibit Delta virus with amitriptyline being a more potent inhibitor than amantadine. In swab samples of Delta variants, both amitriptyline and amantadine inhibited the channel activity of viral proteins with IC 50 values of 0.73mM and 1.11mM, respectively. In swab samples of Omicron variants, amitriptyline inhibited the channel activity with an IC 50 of 0.76mM. Conclusions: We developed an efficient method to screen FDA-approved ion channel modulators that can be repurposed to inhibit SARS-CoV-2 viral replication independent of variants.