Profiling the Response of Rare Cystic Fibrosis Variants to VX-121
Description
To compare the variant-specific effects of VX-121 to those of other current correctors, we employed DMS to survey its effects on the plasma membrane expression of 232 CF variants. Briefly, we first generated a pool of recombinant HEK293T cells in which each individual cell expressed a single CF variant from a uniform genomic locus. We then employed surface immunostaining in conjunction with fluorescent cell sorting in order to separate the pool of cells according to the relative abundance of the CF variants. We then employed deep sequencing to track the distribution of variants across each cellular isolate, which was then used to comparatively estimate the relative plasma membrane expression of each variant in the presence and absence of VX-121. Similar to our previous observations for VX-661 and VX-445, flow cytometry measurements show that the surface immunostaining of CFTR increases across the recombinant cellular library in the presence of VX-121. Overall, we find that VX-121 increases the plasma membrane expression of the tested CF variants, which is comparable to VX-661 and VX-445-sensitive variants. However, we do identify one variant (V1240G) that is more sensitive to VX-121 relative to VX-445. Additionally, our analyses identify another variant (Y1032C) that exhibits diminished sensitivity to VX-121 relative to VX-445. Notably, this variant was previously identified as a VX-445-selective variant in relation to VX-661 as well. Together, these findings demonstrate that, outside of rare exceptions, most variant-specific effects of VX-121 appear to be comparable to those of other current correctors.
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Institutions
- Purdue University SystemIndiana, West Lafayette