(605) Beneficial Effects of SGLT1/2 dual inhibitor Phloridzin on Human iPSC-derived Lung Organoids of Cystic Fibrosis Class I Mutations

Background: More than twenty percent cystic fibrosis (CF) patients carry at least one copy of a Class I mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Class I CFTR mutations (also known as X-mutations) result in nonsense and canonical splice-site mutations, leading to complete absence of CFTR protein. Major Class I mutations include G542X, W1282X, and others. Unfortunately homozygous Class I mutation patients do not benefit from Trikafta (elexacaftor/tezacaftor/ivacaftor), the primary CF drug that has gained FDA’s approval for treating patients with one or two copies of the most prevalent CFTR-F508del (dF) mutation or any other CFTR modulator drugs on the market such as Orkambi (lumacaftor/ivacaftor). Recently we reported that inhibitors to the sodium-dependent glucose cotransporter 1/2 (SGLT1/2), namely Sotagliflozin or Phloridzin, promoted the swelling of dF/dF and dF/G551D human proximal lung organoids (HLOs) derived from induced pluripotent stem cells (iPSCs) in forskolin (Fsk)-stimulated organoid swelling assay. Of note, in addition to its SGLT1/2 inhibiting capacity, Phloridzin is also known as an inhibitor of the Na+/K+-ATPase.

Methods: In the present work we derived HLOs from Class I CF iPSCs with either the G542X/G542X or the W1282X/W1282X mutations. We evaluated the effects of Elexacaftor/tezacaftor/ivacaftor, Sotagliflozin, Phloridzinan, or Amiloride (an epithelial sodium channel inhibitor) on these Class I CF HLOs in the Fsk-stimulated swelling assay.

Results: Unexpectedly only Phloridzin promoted the swelling of G542X/G542X and W1282X/W1282X HLOs, to a similar extent achieved by the CFTR modulators lumacaftor/ivacaftor on dF/dF HLOs, whereas none of the other compounds (Elexacaftor/tezacaftor/ivacaftor, Sotagliflozin or Amiloride) had any effects.

Conclusions: Our data demonstrate a promoting effect of SGLT1/2 inhibitor Phloridzin on the Class I CF HLOs. The differential results by Sotagliflozin and Phloridzin suggest a potential contribution of Na+/K+-ATPase on the Fsk-promoted swelling of Class I CF HLOs. Follow up studies are needed to delineate the roles of SGLT1/2 and Na+/K+-ATPase in Class I CF mutations.

Acknowledgements: This work was supported by the Cystic Fibrosis Foundation grants (HIRAI19XX0).

References: [1] Hirai H, Liang X, Sun Y, Zhang Y, Zhang J, Chen YE, Mou H, Zhao Y, Xu J, The sodium/glucose cotransporters as potential therapeutic targets for cystic fibrosis lung diseases revealed by human lung organoid swelling assay. Molecular Therapy: Methods & Clinical Development 2022; 24:11-19. https://doi.org/10.1016/j.omtm.2021.11.008

[2] Ruan J*, Hirai H*, Yang D, Ma L, Hou X, Jiang H, Wei H, Rajagopalan C, Mou H, Wang G, Zhang J, Li K, Chen YE, Sun F, Xu J, Efficient gene editing at major CFTR mutation loci. Molecular Therapy: Nucleic Acid. 2019; 16: 73-81. https://doi.org/10.1016/j.omtn.2019.02.006