Polystyrene nanoplastics induce mitochondrial dysfunction and stress responses in human PBMCs

Area of Science:

• Environmental Science
• Immunology
• Toxicology

Background:

• Microplastics and nanoplastics (MPs/NPs) are emerging environmental contaminants.
• Human exposure to NPs is increasing, but their effects on immune cells are unclear.

Purpose of the Study:

• Investigate the impact of polystyrene NPs on human peripheral blood mononuclear cells (PBMCs).
• Understand the cellular and molecular mechanisms of NP-induced immune cell responses.

Main Methods:

• Confocal microscopy for NP internalization.
• Optical diffraction tomography for biophysical changes.
• Seahorse metabolic profiling for mitochondrial function.
• Basophil activation assays.
• Single-cell RNA sequencing for transcriptomic analysis.

Main Results:

• 25-nm NPs were efficiently internalized into PBMCs.
• Short-term NP exposure caused significant biophysical remodeling and suppressed mitochondrial respiration.
• A distinct NP-induced 'stress-cell' population with upregulated proteostasis pathways was identified.
• Basophil activation was not affected.

Conclusions:

• NPs rapidly disrupt mitochondrial function and induce proteotoxic stress in human immune cells.
• Findings highlight potential immune dysregulation from nanoplastic pollution within the One Health framework.
• Results inform public health risk assessments for environmental contaminants.