Exposure to low-dose nanopolystyrene induces the response of neuronal JNK MAPK signaling pathway in nematode Caenorhabditis elegans

Background The response of organisms to nanoplastic exposure has gradually received the attention. Nevertheless, the role of neurons in response to nanoplastic exposure and the underlying mechanism are still largely unclear. We here examined the role of neuronal JNK MAPK signaling in response to low-dose of polystyrene (100 nm) in Caenorhabditis elegans. Results Exposure to nanopolystyrene in the range of μg/L could increase the expression of genes (jkk-1, mek-1, and jnk-1) encoding JNK MAPK signaling pathway. Meanwhile, RNAi knockdown of any of these genes induced a susceptibility to nanopolystyrene toxicity. In the neurons, SNB-1/synaptobrevin was identified as the downstream target of JNK-1/JNK, suggesting the alteration in neurotransmitter signals in nanopolystyrene-exposed nematodes. In nanopolystyrene-exposed nematodes, JNK-1 modulated TBH-1-mediated octopamine signal and CAT-2-mediated dopamine signal. TBH-1 and CAT-2 further regulated the response to nanopolystyrene by affecting the function of corresponding intestinal octopamine receptors (SER-6 and OCTR-1) and intestinal dopamine receptor (DOP-1). In the intestine, DOP-1 regulated the response to nanopolystyrene by activating the downstream signaling cascade in p38 MAPK signaling pathway. Conclusions Exposure to low-dose of nanopolystyrene could induce the response of neuronal JNK MAPK signaling pathway in nematodes. Our data further highlight the crucial role of neuronal JNK MAPK signaling-activated alteration in octopamine and dopamine signals in regulating the response to nanopolystyrene in organisms.