Potentiation of ABCA3 lipid transport function by ivacaftor and genistein

Abstract

ABCA3 is a phospholipid transporter implicated in pulmonary surfactant homoeostasis and localized at the limiting membrane of lamellar bodies, the storage compartment for surfactant in alveolar type II cells. Mutations in ABCA3 display a common genetic cause for diseases caused by surfactant deficiency like respiratory distress in neonates and interstitial lung disease in children and adults, for which currently no causal therapy exists. In this study, we investigated the effects of ivacaftor and genistein, two potentiators of the cystic fibrosis transmembrane conductance regulator (CFTR), on ABCA3‐specific lipid transport function. Wild‐type (WT) and functional ABCA3 mutations N568D, F629L, G667R, T1114M and L1580P were stably expressed in A549 cells. Three‐dimensional modelling predicted functional impairment for all five mutants that was confirmed by in vitro experiments (all <14% of WT functional activity). Treatment with potentiators rescued the mutants N568D (up to 114% of WT), F629L (up to 47% of WT), and G667R (up to 60% of WT), the latter variation needing higher concentrations of genistein, showing reduced affinity of the potentiator to the mutant protein. Our results present a first proof that functional ABCA3 mutations are rescued by CFTR potentiators, making them a potential therapeutical option for patients suffering from surfactant deficiency due to ABCA3 mutations.

Functional characterization of four ATP‐binding cassette transporter A3 gene (ABCA3) variants

“…Recently, Kinting et al (2019) demonstrated increased lipid transport activity as measured by the increased portion of labeled phosphatidylcholine (TopF‐PC) filled vesicles and increased fluorescence intensity of filled vesicles when A549 cells expressing the type II mutant c.1702A>G;p.N568D were exposed to CFTR potentiators ivacaftor and genistein. While not all ABCA3 type II mutants studied demonstrated increased lipid transport activity in response to ivacaftor or genistein, these data demonstrate proof of concept for development of pharmacologic strategies to correct ABCA3 function among symptomatic infants and children (Kinting et al, 2019). Quantitative differences in mean vesicle diameter and immunoflourescent colocalization may be useful in pathogenicity screening of uncharacterized ABCA3 variants.…”

Epitope mimicry analysis of SARS-COV-2 surface proteins and human lung proteins

“…We also recommend that further clinical trial should assess the effect of drugs potentiating the effect of ABCA3 like the cystic fibrosis transmembrane conductance regulator e.g. ivacaftor and genistein [ 34 ].…”

Genetic disorders of the surfactant system: focus on adult disease

“…Analogous to successful CFTR therapy, the potentiators ivacaftor and genistein may rescue protein functionality. Recently, these potentiators were shown to rescue the ABCA3 phospholipid transport function of three different mutations stably expressed in A549 cells [145].…”