Abstract
The Nairoviridae family of segmented negative-sense RNA viruses includes the serious human pathogen Crimean-Congo haemorrhagic fever virus (CCHFV), associated with a case/fatality rate of up to 40% for which no approved vaccines or treatments exist. Nairoviruses internalize via endocytosis and pass through the endolysosomal network, exploiting the changing ionic environment to promote envelope fusion. Fusion is influenced by hydrogen (H+) and potassium ions (K+), which increase in concentration as endosomes mature, regulated by host ion channels. Using the model nairovirus Hazara virus (HAZV) of the CCHFV serogroup, we performed an siRNA screen to identify cellular ion channels involved in nairovirus infection. Most high-ranking hits belonged to K+ and calcium (Ca2+) channel families. Consistent with this, we showed that clinically-approved K+ channel blockers quinidine, quinine and dronedarone and clinically-approved Ca2+ channel blockers tetrandrine and nifedipine significantly reduced HAZV activities. To further probe the role of K+ in HAZV infection, we used time-of-addition studies, showing K+ was required during entry. Biochemical experiments showed K+ expanded the pH range that promoted entry, potentially allowing endosome escape deeper within the endolysosomal network. These results show clinically-approved channel blockers effectively inhibit HAZV replication, suggesting repurposing existing therapies may represent promising avenues to block nairovirus infection.
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Acknowledgements
We acknowledge Wellcome trust equipment grant 221538/Z/20/Z, which supports the use of the IncuCyte live cell imaging platform.
Funding
This work was supported by a University of Leeds PhD studentship to FWC, MRC project Grant MR/T016159/1 to JNB, JF, JM and TAE, BBSRC project grant BB/V007467/1 to JNB, JM and HP, grant PID2023-149259NB-I00 funded by MICIU/AEI/ https://doi.org/10.13039/501100011033, a Human Frontiers Science Programme grant RGP0040/2019 awarded to JF, and by “ERDF A way of making Europe” to JF.
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FWC, HMP, SEH and AA acquired the data. FWC, MS, JF and JNB analysed and interpreted the data. TAE and JM made contributions to the conception and design of the work. FWC, JF and JNB wrote the manuscript. FWC made the figures. All authors approved the submitted version of the manuscript.
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Charlton, F.W., Hover, S.E., Alyahyawi, A. et al. Identification of cellular ion channels that facilitate Hazara nairovirus infection enables selection of clinically approved compounds with anti-nairoviral properties. Sci Rep (2026). https://doi.org/10.1038/s41598-026-42810-7
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DOI: https://doi.org/10.1038/s41598-026-42810-7
