PT  - JOURNAL ARTICLE
AU  - Lukas Hinder
AU  - Anna Lena Pfaff
AU  - Rolf Erik Emmerich
AU  - Susanne Michels
AU  - Martin Schlitzer
AU  - Carsten Culmsee
TI  - Characterization of novel diphenylamine compounds as ferroptosis inhibitors
AID  - 10.1124/jpet.121.000534
DP  - 2021 Jan 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - JPET-AR-2021-000534
4099  - http://jpet.aspetjournals.org/content/early/2021/05/19/jpet.121.000534.short
4100  - http://jpet.aspetjournals.org/content/early/2021/05/19/jpet.121.000534.full
AB  - Ferroptosis is a form of oxidative cell death which is increasingly recognized as a key mechanism in neurodegeneration but also in regulated cell death causing disease in other tissues. In neurons, major hallmarks of ferroptosis involve the accumulation of lipid reactive oxygen species (ROS) and impairment of mitochondrial morphology and function. Compounds that interfere with ferroptosis could provide novel treatment options for neurodegenerative disorders and other diseases involving ferroptosis. In the present study, we developed new compounds by refining structural elements of the BID inhibitor BI-6c9, that was previously demonstrated to block ferroptosis signaling at the level of mitochondria. Here, we inserted an antioxidative diphenylamine (DPA) structure to the BI-6c9 structure. These DPA compounds were then tested in models of erastin and RSL-3 induced ferroptosis in neuronal HT22 cells. The DPA compounds showed an increased protective potency against ferroptotic cell death compared to the scaffold molecule BI-6c9. Moreover, hallmarks of ferroptosis like lipid, cytosolic and mitochondrial ROS formation were abrogated in a concentration and time-dependent manner. Additionally, mitochondrial parameters such as mitochondrial morphology, mitochondrial membrane potential as well as mitochondrial respiration were preserved by the DPA compounds, supporting the conclusion that lipid ROS toxicity and mitochondrial impairment are closely related in ferroptosis. Our findings confirm that the DPA compounds are very effective agents in preventing ferroptotic cell death by blocking ROS production and, in particular, via mitochondrial protection. Significance Statement Preventing neuronal cells from different forms of oxidative cell death was previously described as a promising strategy for treatment against several neurodegenerative diseases. In this study, we report novel compounds based on a diphenylamine structure that strongly protect neuronal HT22 cells from ferroptotic cell death upon erastin and RSL-3 induction by preventing the development of different ROS species and by protecting mitochondria from ferroptotic impairments.