Heme Induces BECN1/ATG5-Mediated Autophagic Cell Death via ER Stress in Neurons

Intracerebral hemorrhage (ICH) is a serious medical problem, and effective treatment is limited. Hemorrhaged blood is highly toxic to the brain, and heme, which is mainly released from hemoglobin, plays a vital role in neurotoxicity. However, the specific mechanism involved in heme-mediated neurotoxicity has not been well studied. In this study, we investigated the neurotoxicity of heme in neurons. Neurons were treated with heme, and cell death, autophagy, and endoplasmic reticulum (ER) stress were analyzed. In addition, the relationship between autophagy and apoptosis in heme-induced cell death and the downstream effects were also assessed. We showed that heme induced cell death and autophagy in neurons. The suppression of autophagy using either pharmacological inhibitors (3-methyladenine) or RNA interference of essential autophagy genes (BECN1 and ATG5) decreased heme-induced cell death in neurons. Moreover, the ER stress activator thapsigargin increased cell autophagy and the cell death ratio following heme treatment. Autophagy promoted heme-induced cell apoptosis and cell death through the BECN1/ATG5 pathway. Our findings suggest that heme potentiates neuronal autophagy via ER stress, which in turn induces cell death via the BECN1/ATG5 pathway. Targeting ER stress-mediated autophagy might be a promising therapeutic strategy for ICH.

Keywords: Autophagic death; ER stress; Heme; Neuron.