Microglial ferroptotic stress causes non-cell autonomous neuronal death

Area of Science:

• Neuroscience
• Cell Biology
• Pathology

Background:

• Ferroptosis, a regulated cell death marked by lipid peroxidation and iron dependence, plays a dual role in disease, contributing to neuronal death in neurodegenerative conditions.
• While ferroptosis is known to protect against cancer and infection, its precise role in central nervous system (CNS) neurodegeneration remains unclear.

Purpose of the Study:

• To investigate the role of ferroptosis in neuronal death within the context of neurodegenerative diseases.
• To elucidate the mechanisms by which ferroptosis influences neuronal survival and to explore potential therapeutic interventions.

Main Methods:

• Utilized co-culture systems with microglia, astrocytes, and neurons, alongside conditioned medium transfer experiments.
• Assessed human amyotrophic lateral sclerosis (ALS) spinal cord tissue and employed the SOD1G37R mouse model of ALS.
• Administered a CNS-permeant ferroptosis inhibitor (CuII(atsm)) in vivo to evaluate its therapeutic potential.

Main Results:

• Sublethal ferroptotic stress in microglia induced an inflammatory cascade leading to non-cell autonomous neuronal death.
• Astrocytes were converted to a neurotoxic state, contributing to the observed neuronal death.
• Human ALS spinal cord tissue exhibited a ferroptosis signature, which was mirrored in the SOD1G37R mouse model; treatment with CuII(atsm) ameliorated these markers and demonstrated neuroprotection.

Conclusions:

• Microglial ferroptotic stress is implicated as a key factor in non-cell autonomous neuronal death, suggesting it as a targetable cause of neuronal loss in neurodegenerative diseases.
• These findings reveal a novel pathophysiological role for ferroptosis beyond its traditional view as an intrinsic cell death mechanism, opening new avenues for therapeutic development in neurodegeneration.