Ibrutinib Contributes to Atrial Arrhythmia through the Autophagic Degradation of Connexins by Inhibiting the PI3K-AKT-mTOR Signaling Pathway

Background : Ibrutinib could increase the risk of atrial fibrillation (AF) in chronic lymphocytic leukemia (CLL) patients. However, the precise mechanism underlying ibrutinib-induced AF remains incompletely elucidated. Methods : We investigated the proportion of ibrutinib-treated CLL patients with new -onset AF. Optical mapping was conducted to reveal the proarrhythmic effect of ibrutinib on HL -1 cells. Fluorescence staining and western blot were used to compare connexins 43 and 40 expression in ibrutinib-treated and control groups. To identify autophagy phenotypes, we used western blot to detect autophagy-related proteins, transmission electron microscopy to picture autophagosomes, and transfected mCherry-GFP-LC3 virus to label autophagosomes and lysosomes. Hydroxychloroquine as an autophagy inhibitor was administered to rescue ibrutinib-induced Cx43 and Cx40 degradation. Results : About 2.67% of patients developed atrial arrhythmias after ibrutinib administration. HL -1 cells treated with ibrutinib exhibited diminished conduction velocity and a higher incidence of reentry -like arrhythmias compared to controls. Cx43 and Cx40 expression reduced along with autophagy markers increased in HL -1 cells treated with ibrutinib. Inhibiting autophagy upregulated Cx43 and Cx40. Conclusions : The off -target effect of ibrutinib on the PI3K-AKT-mTOR signaling pathway caused connexin degradation and atrial arrhythmia via promoting autophagy. Clinical Trial Registration : ChiCTR2100046062, https://clin.larvol.com/trial-detail/ChiCTR2100046062.