Rotenone exerts developmental neurotoxicity in a human brain spheroid model

Area of Science:

• Neuroscience
• Toxicology
• Stem Cell Biology

Background:

• Chemicals may cause developmental neurotoxicity (DNT), linked to disorders like autism and ADHD.
• Current DNT testing is expensive, necessitating cost-effective alternatives.
• Human induced pluripotent stem cells (iPSC) and 3D culture models offer novel toxicity prediction tools.

Purpose of the Study:

• To develop and validate a human iPSC-derived 3D brain model (BrainSpheres) for assessing chemical DNT.
• To investigate the neurotoxic effects of rotenone on different neuronal cell types and differentiation stages.

Main Methods:

• Generation of multicellular brain spheroids (BrainSpheres) from human iPSC.
• Exposure of BrainSpheres to rotenone at varying concentrations and differentiation stages.
• Assessment of cell viability, reactive oxygen species (ROS), mitochondrial dysfunction, and cell-specific toxicity using immuno-fluorescence.
• Analysis of molecular pathways affected by rotenone using omics techniques.

Main Results:

• Rotenone's toxicity varied with cell differentiation status, with higher ROS and mitochondrial dysfunction in early stages.
• Dopaminergic neurons were selectively targeted by rotenone at non-cytotoxic concentrations (1 µM).
• Omics analysis revealed rotenone's impact on brain development pathways, including Ca2+ reabsorption, synaptogenesis, and PPAR signaling.

Conclusions:

• The BrainSpheres model is a reproducible and effective tool for studying neurotoxicity and DNT.
• Rotenone demonstrates potential as a developmental neurotoxicant, with distinct effects based on cell differentiation stage.
• This model aids in understanding chemical impacts on neurodevelopment and identifying potential risks for neurological disorders.