3,4-methylenedioxymethamphetamine induces reactive oxygen species-mediated autophagy and thioredoxin-interactive protein/nucleotide-binding domain, leucine-rich containing family, pyrin domain-containing-3 inflammasome activation in dental pulp stem cells

Background/purpose: 3,4-methylenedioxymethamphetamine (MDMA) is a synthetic substituted amphetamine. Research primarily focuses on its neurotoxicity and psychological effects, while studies examining its impact on mesenchymal stem cells (MSCs) and dental pulp stem cells (DPSCs) are relatively limited. This study investigated the cytotoxicity and molecular mechanisms of MDMA in DPSCs.

Materials and methods: Cell viability, Apoptosis, Autophagy, immunophenotype, Reactive Oxygen Species (ROS), and the related signaling pathways were analyzed using a cell counting kit, Western blot, flow cytometry, and 2',7'-dichlorofluorescein diacetate (DCFH-DA) dye after treating DPSCs with indicated concentrations of MDMA.

Results: MDMA significantly decreased cell viability and increased cleaved poly adenosine diphosphate-ribose polymerase (PARP), cleaved Caspase-8, cleaved Caspase-3, and Bcl-2-associated X protein (Bax), while reducing B-cell lymphoma 2 (Bcl-2). Annexin V and 7-aminoactinomycin D (7-AAD) flow cytometry showed that these cells underwent early Apoptosis without altering MSCs' immunophenotypic properties. MDMA also induced ROS accumulation and nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) inflammasome activation. Autophagy activation was observed with adenosine monophosphate-activated protein kinase (AMPK) activation, protein kinase B (Akt) inactivation, and mammalian target of rapamycin (mTOR) suppression. Autophagy inhibitor chloroquine (CQ) attenuated MDMA-induced cell death, suggesting that excessive Autophagy contributes to cell damage.

Conclusion: MDMA induces ROS-mediated autophagic cell death and thioredoxin-interacting protein (TXNIP)/NLRP3 inflammasome activation, causing detrimental cell damage. The historical roots of drug addiction should be considered when modifying dental approaches for patients with a history of MDMA use, as well as in the screening of DPSCs donors and patients undergoing stem cell therapy.

3,4-methylenedioxymethamphetamine (MDMA); Autophagy; Dental pulp stem cells (DPSCs); Nucleotide-binding domain, leucine-rich containing family, pyrin domain-containing-3 (NLRP3) inflammasome; Oxidative stress.