Microplastics dysregulate innate immunity in the SARS-CoV-2 infected lung

Area of Science:

• Environmental Health
• Immunology
• Toxicology

Background:

• Microplastic (MP) pollution is a global concern, with increasing evidence of human and animal exposure.
• Potential health impacts of microplastics, particularly in the context of respiratory infections, require further investigation.

Purpose of the Study:

• To investigate the effects of microplastic (MP) beads on the host response to SARS-CoV-2 omicron BA.5 infection in a mouse model.
• To analyze the impact of MPs on viral clearance, innate immunity, and inflammatory signatures during COVID-19.

Main Methods:

• A mouse model of mild COVID-19 was used, co-delivering 1 μm polystyrene MP beads with SARS-CoV-2 omicron BA.5.
• Histopathology and RNA-Seq were employed to analyze host response at 2 and 6 days post-infection (dpi).

Main Results:

• Microplastics did not significantly alter virus titres or RNA levels, despite reduced MP clearance from the lungs post-infection.
• RNA-Seq revealed suppressed innate immune responses at 2 dpi and increased pro-inflammatory signatures at 6 dpi.
• The observed cytokine profile at 6 dpi correlated with the 'cytokine release syndrome' signature in some COVID-19 patients.

Conclusions:

• Microplastic exposure can dysregulate inflammatory processes during viral infections.
• Findings suggest MPs may inhibit phagocytosis and alter immune cell function.
• Further research is needed to understand the long-term health implications of microplastic exposure in disease settings.