Polystyrene nanoplastic exposure increases susceptibility of Pseudomonas aeruginosa infection in Caenorhabditis elegans model of host-pathogen interaction in p38-MAP Kinase dependent manner

Nanoplastics have been shown to be potential environmental hazardous material, however not much is known on their role in modulating infection susceptibility and host-pathogen relationship. Present study investigated the role of polystyrene nanoparticles (PSNP) on infectivity of pathogenic Pseudomonas aeruginosa in Caenorhabditis elegans model. Physiochemical characterization of PSNP was done by Dynamic Light Scattering (DLS) and Fourier Transform Infrared Spectroscopy (FTIR). The internalization in C. elegans was determined by FTIR. Effect of PSNP in worms infected with P. aeruginosa was assessed through various toxicological parameters including survival, bacterial load, growth, behavior, and reproduction. PSNP (∼100 nm in size) exposure to P. aeruginosa-infected C. elegans did not alter their survivability, but affected the transition from larval stage to adult worms. PSNP exposure also affected the growth, progeny and locomotory behavior in P. aeruginosa-infected worms. FTIR analysis readily confirmed PSNP internalization in C. elegans. Interestingly, PSNP-exposure to mutant C. elegans, with compromised innate immunity due to p38-MAP Kinase deletion, resulted in enhanced susceptibility to P. aeruginosa infection, as evident from more severe defects in locomotory and reproductive behavior compared to P. aeruginosa alone infected worms. Overall, these results revealed that PSNP exposure enhanced susceptibility to P. aeruginosa infection by possibly compromising the immune response. This study emphasized the importance of understanding the hazardous effects of nanoplastic exposure on host-pathogen relation in humans.