Niclosamide inhibits SARS-CoV2 entry by blocking internalization through pH-dependent CLIC/GEEC endocytic pathway

Prabhakara, C.; Godbole, R.; Sil, P.; Jahnavi, S.; van Zanten, T. S.; Sheth, D.; Subhash, N.; Chandra, A.; Nuthakki, V. K.; Puthiyapurayil, T. P.; Ahmed, R.; Najar, A. H.; Lingamallu, S. M.; Das, S.; Mahajan, B.; Vemula, P. K.; Bharate, S. B.; Singh, P. P.; Vishwakarma, R.; Guha, A.; Sundaramurthy, V.; Mayor, S.

doi:10.1101/2020.12.16.422529

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bioRxiv · 10.1101/2020.12.16.422529

Niclosamide inhibits SARS-CoV2 entry by blocking internalization through pH-dependent CLIC/GEEC endocytic pathway

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Abstract

Many viruses utilize the host endo-lysosomal network to infect cells. Tracing the endocytic itinerary of SARS-CoV2 can provide insights into viral trafficking and aid in designing new therapeutic targets. Here, we demonstrate that the receptor binding domain (RBD) of SARS-CoV2 is internalized via the clathrin and dynamin-independent, pH-dependent CLIC/GEEC (CG) endocytic pathway. Endosomal acidification inhibitors like BafilomycinA1 and NH4Cl, which inhibit the CG pathway, strongly block the uptake of RBD. Using transduction assays with SARS-CoV2 Spike-pseudovirus, we confirmed that these acidification inhibitors also impede viral infection. By contrast, Chloroquine neither affects RBD uptake nor extensively alters the endosomal pH, yet attenuates Spike-pseudovirus entry, indicating a pH-independent mechanism of intervention. We screened a subset of FDA-approved acidification inhibitors and found Niclosamide to be a potential SARS-CoV2 entry inhibitor. Niclosamide, thus, could provide broader applicability in subverting infection of similar category viruses entering host cells via this pH-dependent endocytic pathway.

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Prabhakara, C., Godbole, R., Sil, P., Jahnavi, S., van Zanten, T. S., Sheth, D., Subhash, N., Chandra, A., Nuthakki, V. K., Puthiyapurayil, T. P., Ahmed, R., Najar, A. H., Lingamallu, S. M., Das, S., Mahajan, B., Vemula, P. K., Bharate, S. B., Singh, P. P., Vishwakarma, R., Guha, A., Sundaramurthy, V., Mayor, S.. 2020-12-16. Niclosamide inhibits SARS-CoV2 entry by blocking internalization through pH-dependent CLIC/GEEC endocytic pathway. https://doi.org/10.1101/2020.12.16.422529

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