tetano
Editor, Senior Moderator
Antiviral Res
. 2024 Jul 11:105961.
doi: 10.1016/j.antiviral.2024.105961. Online ahead of print. High throughput profiling identified PA-L106R amino acid substitution in A(H1N1)pdm09 influenza virus that confers reduced susceptibility to baloxavir in vitro
Dongdong Chen[SUP] 1 [/SUP], Wen Su[SUP] 1 [/SUP], Ka-Tim Choy[SUP] 1 [/SUP], Yan Sing Chu[SUP] 2 [/SUP], Chi Ho Lin[SUP] 2 [/SUP], Hui-Ling Yen[SUP] 3 [/SUP]
Affiliations
Baloxavir acid (BXA) is a pan-influenza antiviral that targets the cap-dependent endonuclease of the polymerase acidic (PA) protein required for viral mRNA synthesis. To gain a comprehensive understanding on the molecular changes associated with reduced susceptibility to BXA and their fitness profile, we performed a deep mutational scanning at the PA endonuclease domain of an A(H1N1)pdm09 virus. The recombinant virus libraries were serially passaged in vitro under increasing concentrations of BXA followed by next-generation sequencing to monitor PA amino acid substitutions with increased detection frequencies. Enriched PA amino acid changes were each introduced into a recombinant A(H1N1)pdm09 virus to validate their effect on BXA susceptibility and viral replication fitness in vitro. The I38T/M substitutions known to confer reduced susceptibility to BXA were invariably detected from recombinant virus libraries within 5 serial passages. In addition, we identified a novel L106R substitution that emerged in the third passage and conferred greater than 10-fold reduced susceptibility to BXA. PA-L106 is highly conserved among seasonal influenza A and B viruses. Compared to the wild-type virus, the L106R substitution resulted in reduced polymerase activity and a minor reduction of the peak viral load, suggesting the amino acid change may result in moderate fitness loss. Our results support the use of deep mutational scanning as a practical tool to elucidate genotype-phenotype relationships, including mapping amino acid substitutions with reduced susceptibility to antivirals.
Keywords: Baloxavir; cap-dependent endonuclease inhibitor; deep mutational scanning; fitness; influenza virus; reduced susceptibility.
. 2024 Jul 11:105961.
doi: 10.1016/j.antiviral.2024.105961. Online ahead of print. High throughput profiling identified PA-L106R amino acid substitution in A(H1N1)pdm09 influenza virus that confers reduced susceptibility to baloxavir in vitro
Dongdong Chen[SUP] 1 [/SUP], Wen Su[SUP] 1 [/SUP], Ka-Tim Choy[SUP] 1 [/SUP], Yan Sing Chu[SUP] 2 [/SUP], Chi Ho Lin[SUP] 2 [/SUP], Hui-Ling Yen[SUP] 3 [/SUP]
Affiliations
- PMID: 39002800
- DOI: 10.1016/j.antiviral.2024.105961
Baloxavir acid (BXA) is a pan-influenza antiviral that targets the cap-dependent endonuclease of the polymerase acidic (PA) protein required for viral mRNA synthesis. To gain a comprehensive understanding on the molecular changes associated with reduced susceptibility to BXA and their fitness profile, we performed a deep mutational scanning at the PA endonuclease domain of an A(H1N1)pdm09 virus. The recombinant virus libraries were serially passaged in vitro under increasing concentrations of BXA followed by next-generation sequencing to monitor PA amino acid substitutions with increased detection frequencies. Enriched PA amino acid changes were each introduced into a recombinant A(H1N1)pdm09 virus to validate their effect on BXA susceptibility and viral replication fitness in vitro. The I38T/M substitutions known to confer reduced susceptibility to BXA were invariably detected from recombinant virus libraries within 5 serial passages. In addition, we identified a novel L106R substitution that emerged in the third passage and conferred greater than 10-fold reduced susceptibility to BXA. PA-L106 is highly conserved among seasonal influenza A and B viruses. Compared to the wild-type virus, the L106R substitution resulted in reduced polymerase activity and a minor reduction of the peak viral load, suggesting the amino acid change may result in moderate fitness loss. Our results support the use of deep mutational scanning as a practical tool to elucidate genotype-phenotype relationships, including mapping amino acid substitutions with reduced susceptibility to antivirals.
Keywords: Baloxavir; cap-dependent endonuclease inhibitor; deep mutational scanning; fitness; influenza virus; reduced susceptibility.