Transgenerational response of germline histone acetyltransferases and deacetylases to nanoplastics at predicted environmental doses in Caenorhabditis elegans.

Nanoplastics could cause toxic effects on organism and their offsprings; however, how this transgenerational toxicity is formed remains largely unclear. We here examined potential involvement of germline histone acetylation regulation in modulating transgenerational toxicity of polyetyrene nanoparticle (PS-NP) in Caenorhabditis elegans. At parental generation (P0-G), PS-NP (1-100 μg/L) decreased expressions of germline cbp-1 and taf-1 encoding histone acetyltransferases, as well as germline expressions of sir-2.1 and hda-3 encoding histone deacetylase. Decrease in these 4 germline genes were also observed in the offspring of PS-NP (1-100 μg/L) exposed nematodes. Germline RNAi of cbp-1, taf-1, sir-2.1 and hda-3 resulted in more severe transgenerational PS-NP toxicity on locomotion and brood size. Meanwhile, in PS-NP exposed nematodes, germline RNAi of cbp-1, taf-1, sir-2.1 and hda-3 increased expression of genes encoding insulin, FGF, Wnt, and/or Notch ligands and expressions of their receptor genes in the offspring. Susceptibility to transgenerational PS-NP toxicity in cbp-1(RNAi), taf-1(RNAi), sir-2.1(RNAi), and hda-3 (RNAi) was inhibited by RNAi of these germline ligands genes. Moreover, histone deacetylase inhibition served as molecular initiating event (MIE) leading to transgenerational toxicity in epigenetic adverse outcome pathway (AOP) for nanoplastics. Our data provided evidence that germline histone acetylation regulation functioned as an important mechanism for transgenerational toxicity of nanoplastics at predicted environmental doses (PEDs) by affecting secreted ligands in organisms.