N-acetylcysteine increases alpha-1 antitrypsin expression and secretion in a Z-AATD cell model

<bold>Background:</bold> Alpha-1 antitrypsin deficiency (AATD) is a hereditary condition characterized by low alpha-1 antitrypsin (AAT) plasma levels, increasing the risk of lung and liver disease. Mutated Z-AAT proteins polymerize and accumulate inside the hepatocytes, generating a systemic inflammatory response. Augmentation therapy is the only approved pharmacological therapy to treat emphysema. No pharmacological intervention exists for treating AATD-associated liver disease. Therefore, new therapeutic strategies for AATD treatment are needed. Oxidative stress is increased in AATD patients, which opens up a rationale for using antioxidant therapies to treat the disease. We hypothesize that n-acetylcysteine (NAC), a potent antioxidant, decreases Z-AAT intracellular polymerization and increases Z-AAT secretion. Therefore, this work <italic>aims</italic> to assess the effect of NAC on AAT expression, polymerization, secretion, and oxidative state in a Z-HEK293 cell model. <bold>Methods:</bold> HEK293 cells producing the human Z-AAT protein (Z-HEK293) were treated with 10 mM NAC for 72 hours. Cell viability was assessed by trypan blue exclusion. AAT expression was evaluated by qRT-PCR. AAT secretion and oxidative state were determined by ELISA. <bold>Results:</bold> Our results indicate that NAC does not affect cell viability at the indicated doses. NAC treatment results in a significant two-fold increase in the <italic>SERPINA1</italic> gene expression (p=0.003), increased AAT secretion (p=0.08), and reduced AAT oxidation (p=0.03). <bold>Conclusions:</bold> Our results indicate that NAC might be useful for treating AATD patients. <bold>Funding:</bold> Funded by 2017 SVN, ISCIII #PI17/01250, European Regional Development Funds, 2024 CSL-Behring, 2021 Amadeu Monteiro grants.