TFEB regulates cellular labile iron and prevents ferroptosis in a TfR1-dependent manner

Autophagy is a major clearance pathway for misfolded α-synuclein which promotes ferroptosis through NCOA4-mediated ferritin degradation. The regulation of these two processes to achieve improved neuroprotection in Parkinson's disease (PD) must be elucidated. Transcription factor EB (TFEB) is a master regulator of both autophagy and lysosome biogenesis, and lysosomes are important cellular iron storage organelles; however, the role of TFEB in ferroptosis and iron metabolism remains unclear. In this study, TFEB overexpression promoted the clearance of misfolded α-synuclein and prevented ferroptosis and iron overload. TFEB overexpression up-regulated transferrin receptor 1 (TfR1) synthesis and increased the localization of TfR1 in the lysosome, facilitating lysosomal iron import and transient lysosomal iron storage. TFEB overexpression increased the levels of cellular iron-safe storage proteins (both ferritin light and heavy chains). These functions in iron metabolism maintain the cellular labile iron at a low level and electrical activity, even under iron overload conditions. Notably, lower levels of cellular labile iron and the upregulation of ferritin light and heavy chains were reversed after TfR1 knockdown in cells overexpressing TFEB, indicating that TFEB regulates cellular labile iron and suppresses ferroptosis in a TfR1 dependent manner. Taken together, this evidence of the regulation of iron metabolism enriches our understanding of the function of TFEB. In addition, TFEB overexpression protects against ferroptosis and iron overload and provides a new direction and perspective for autophagy regulation in PD.