Thiopurines Impair the Apical Plasma Membrane Expression of CFTR in Pancreatic Ductal Cells via RAC1 Inhibition

Tél, Bálint and Papp, Noémi and Varga, Árpád and Szabó, Viktória and Görög, Marietta and Susánszki, Petra and Crul, Tim and Kiss, Aletta and Sendstad, Ingrid H. and Bagyánszki, Mária and Bódi, Nikolett and Hegyi, Péter and Maléth, József and Pallagi, Petra (2023) Thiopurines Impair the Apical Plasma Membrane Expression of CFTR in Pancreatic Ductal Cells via RAC1 Inhibition. CELLULAR AND MOLECULAR LIFE SCIENCES, 80 (1). No.-31. ISSN 1420-682X (print); 1420-9071 (online)

Preview

Text Teletal2023.pdf Available under License Creative Commons Attribution. Download (12MB) | Preview

Abstract

Background and aims Thiopurine-induced acute pancreatitis (TIP) is one of the most common adverse events among infammatory bowel disease patients treated with azathioprine (AZA), representing a signifcant clinical burden. Previous studies focused on immune-mediated processes, however, the exact pathomechanism of TIP is essentially unclear. Methods To model TIP in vivo, we triggered cerulein-induced experimental pancreatitis in mice receiving a daily oral dose of 1.5 mg/kg AZA. Also, freshly isolated mouse pancreatic cells were exposed to AZA ex vivo, and acinar cell viability, ductal and acinar Ca2+ signaling, ductal Cl–and HCO3–secretion, as well as cystic fbrosis transmembrane conductance regulator (CFTR) expression were assessed using microscopy techniques. Ras-related C3 botulinum toxin substrate (RAC1) activity was measured with a G-LISA assay. Super-resolution microscopy was used to determine protein colocalization. Results We demonstrated that AZA treatment increases tissue damage in the early phase of cerulein-induced pancreatitis in vivo. Also, both per os and ex vivo AZA exposure impaired pancreatic fuid and ductal HCO3– and Cl–secretion, but did not afect acinar cells. Furthermore, ex vivo AZA exposure also inhibited RAC1 activity in ductal cells leading to decreased co-localization of CFTR and the anchor protein ezrin, resulting in impaired plasma membrane localization of CFTR. Conclusions AZA impaired the ductal HCO3– and Cl–secretion through the inhibition of RAC1 activity leading to diminished ezrin-CFTR interaction and disturbed apical plasma membrane expression of CFTR. We report a novel direct toxic efect of AZA on pancreatic ductal cells and suggest that the restoration of ductal function might help to prevent TIP in the future.

Actions (login required)

Edit Item