Background: Tumor Suppressor gene phosphatase and tensin homolog (PTEN) plays a lesser known role in innate and adaptive immunity. PTEN has been shown to form a complex with CFTR at the plasma membrane which is reported to be compromised in cystic fibrosis (CF). Altered miRNA expression in CF have been implicated in immune response regulation and numerous studies have outlined miRNA regulation of PTEN. For example, miR-21 has been observed to be decreased in airway epithelial cells from individuals with CF and is a validated regulator of PTEN gene expression. Here, we sought to examine PTEN regulation by miR-21 in CF iPSC-derived airway epithelial cells. 

Methods: Airway organoids were generated using iPSC from two individuals homozygous for the F508del mutation (?F508/?F508) and their gene corrected counterparts (?F508/wild-type [WT]) employing directed differentiation. Expression of miR-21 and selected target genes (PTEN and PDCD4) were examined in CF versus CF corrected iPSC lines following directed differentiation of iPSC into proximal airway organoids. Gene and miRNA expression was examined by qRT-PCR. 

Results: Expression of miR-21 was observed to be decreased in CF iPSC-derived versus CF corrected lines differentiated in 3D to organoid airway cultures (>Day 30) with reciprocal expression of its validated target genes PTEN and PDCD4.

Conclusion: Reduced miR-21 expression accompanied by increased PTEN expression in CF vs. CF corrected lines may represent an anti-inflammatory mechanism to compensate for the high proinflammatory burden in CF. Ongoing studies aim to elucidate the impact of the miR-21:PTEN relationship in the CF airway epithelium.