Effect of arsenic in epithelial cells with Impaired activity of the CFTR

SOTOMAYOR V; CLAUZURE M; VALDIVIESO AG; PÉREZ CA; VENTURINO A; SANTA COLOMA TA

Buenos Aires

Congreso; Reunión Conjunta de Sociedades de Biociencia; 2017

SAA, SAB, SAIB, SAIC, SAI, SAFE, SAH, SAP, SAB, SAFIS

Little is known about the effects of environmentally relevant levels of arsenic on ion channels. Cystic Fibrosis, an inherited disease affecting 1:2500 newborn babies, is characterized by mutations in the CFTR, gene encoding a cAMP-regulated chloride channel. The aim of this study was to determine how arsenic affects mammalian cells with a diminished activity of the CFTR; it is known that the metalloid elicits its effect through mitochondrial pathways which, in cystic fibrosis is deeply compromise. IB3-1 (ATCC CRL-2777, a bronchial cell line derived from a cystic fibrosis patient with a DF508/W1282X CFTR genotype) and S9 (ATCC CRL-2778, which are IB3-1 cells transduced with an adeno-associated viral vector to stably express wt-CFTR) were exposed to As III (NaAsO2) (0 and 200 uM) for 2 hrs. Crystal violet assay results in S9 and IB3-1 epithelial cells showed IB3-1 cells to be less viable than S9 to As 10 uM when exposed for 2 hrs, but S9 cells were more prone to apoptosis measured by Annexin-V and Propidium iodide apotosis/necrosis assay and flux cytometry (significant differences were assessed by ANOVA and Fisher?s LSD at p =0.01). This might be due to mitochondrial activity impairment and its involvement in apoptosis. Using synchrotron technology at the Synchrotron facility of Campinas in Brazil, we determined speciation in cells exposed for 2 hrs to As (III) 100 uM. This result showed us that As was mainly found as As+3 form and that might be binding sulfur, such as As-Glutathione, a well-known detoxifying pathway for As. Taken together, this results partially explains the importance of mitochondrial functionality and GSH detoxifying pathway in cells exposed to As III, even at concentrations of As below permitted levels in drinking water, and for as little as 2 hrs of exposure. Our next step is to study the effects of the metalloid on the expression of CFTR and CFTR-dependent genes.