neuropeptide NLP-27 enhances neurodegeneration and paralysis in an opioid-like manner during fungal infection.

The nervous system of metazoans is involved in host-pathogen interactions to control immune activation. In , this includes sleep induction, mediated by neuropeptide-like proteins (NLPs), which increases the chance of survival after wounding. Here we analyzed the role of NLP-27 in the infection of with the nematode-trapping fungus Early responses of were the upregulation of , the induction of paralysis (sleep), and neurodegeneration of the mechanosensing PVD (Posterior Ventral Process D) neurons. Deletion of reduced neurodegeneration during fungal attack. Induction of was independent of the MAP kinase PMK-1, and expression of in the hypodermis was sufficient to induce paralysis, although NLP-27 was also upregulated in head neurons. NLP-27 contains the pentapeptide YGGYG sequence known to bind the human μ- and κ-type opioid receptors suggesting NLP-27 or peptides thereof act on opioid receptors. The opioid receptor antagonist naloxone shortened the paralysis time like overexpression of NLP-27.