Deficiency of ALADIN impairs redox homeostasis in human adrenal cells and inhibits steroidogenesis.

[triple a syndrome]

Triple A syndrome is a rare , autosomal recessive cause of adrenal failure . Additional features include alacrima , achalasia of the esophageal cardia , and progressive neurodegenerative disease . The AAAS gene product is the nuclear pore complex protein alacrima -achalasia -adrenal insufficiency neurological disorder (ALADIN ), of unknown function . Triple A syndrome patient dermal fibroblasts appear to be more sensitive to oxidative stress than wild-type fibroblasts . To provide an adrenal and neuronal -specific disease model , we established AAAS -gene knockdown in H 295 R human adrenocortical tumor cells and SH-SY 5 Y human neuroblastoma cells by lentiviral short hairpin RNA transduction . AAAS -knockdown significantly reduced cell viability in H 295 R cells . This effect was exacerbated by hydrogen peroxide treatment and improved by application of the antioxidant N-acetylcysteine . An imbalance in redox homeostasis after AAAS knockdown was further suggested in the H 295 R cells by a decrease in the ratio of reduced to oxidized glutathione . AAAS -knockdown SH-SY 5 Y cells were also hypersensitive to oxidative stress and responded to antioxidant treatment . A further impact on function was observed in the AAAS -knockdown H 295 R cells with reduced expression of key components of the steroidogenic pathway , including steroidogenic acute regulatory and P 450 c 11 β protein expression . Importantly a significant reduction in cortisol production was demonstrated with AAAS knockdown , which was partially reversed with N-acetylcysteine treatment .Our in vitro data in AAAS -knockdown adrenal and neuronal cells not only corroborates previous studies implicating oxidative stress in this disorder but also provides further insights into the pathogenic mechanisms in triple A syndrome .