Microglia ferroptosis is prevalent in neurodegenerative disease and regulated by SEC24B

Abstract

Iron dysregulation has been implicated in multiple neurodegenerative diseases, including Parkinsons Disease (PD), Amyotrophic Lateral Sclerosis (ALS), and Multiple Sclerosis (MS). One prominent feature of affected brain regions are iron-loaded microglia, but how iron overload influences microglia physiology and disease response is poorly understood. Here we show that microglia are highly susceptible to ferroptosis, an iron-dependent form of cell death. In a tri-culture of human iPSC-derived neurons, astrocytes, and microglia, under ferroptosis-inducing conditions, microglia undergo a drastic shift in cell state, with increased ferritin levels, disrupted glutathione homeostasis, and altered cytokine signaling. Similar ferroptosis-associated signature (FAS) microglia were uncovered in PD, and the signature was also found in a large cohort of PD patient blood samples, raising the possibility that ferroptosis can be identified clinically. We performed a genome-wide CRISPR screen which revealed a novel regulator of ferroptosis, the vesicle trafficking gene SEC24B. A small molecule screen also nominated several candidates which blocked ferroptosis, some of which are already in clinical use. These data suggest that ferroptosis sits at the interface of cell death and inflammation, and inhibition of this process in microglia and other brain cells may provide new ways for treating neurodegenerative disease.