Antidepressant indatraline induces autophagy and inhibits restenosis via suppression of mTOR/S6 kinase signaling pathway

Indatraline is an antidepressive agent and a non-selective monoamine transporter inhibitor that blocks the reuptake of neurotransmitters (dopamine, serotonin, and norepinephrine). In this study, we report that indatraline induces autophagy via the suppression of mTOR/S6 kinase signaling. Autophagy induction was examined by a cell-based high content screening system using LysoTracker, which was followed by monodansylcadaverine staining and transmission electron microscope observation. Indatraline increased the number of EGFP-LC3 cells expressing autophagosomes in the cytoplasm. Conversion of LC3 was further validated by immunoblotting. Indatraline induced autophagy by affecting the AMPK/mTOR/S6K signaling axis and had no influence on the PI3K/AKT/ERK signaling. Moreover, indatraline induced autophagy in smooth muscle cells (SMCs); further, it exhibited therapeutic potential for restenosis by inhibiting SMC accumulation in a rat restenosis model. These results provide new insights into the role of monoamine transporters in autophagy regulation and identify indatraline as a novel agent for inducing autophagy.