A possible role of Painless channel in the regulation of immune system activity in Tenebrio molitor L.

The immunomodulatory properties of transient receptor potential (TRP) channels in insects are poorly understood. Here, we provide evidence of the immunoregulatory role of one of the TRPA (transient receptor potential ankyrin) channels, Painless, in the mealworm beetle (Tenebrio molitor), an economically important insect species. Our research revealed that the expression patterns of Painless gene vary across different phases of the immune response. Additionally, we show that the cytokine Spätzle-like protein significantly influences the expression of Painless gene. Furthermore, we report that an allyl isothiocyanate (AITC), TRPA channel agonist which may activate the Painless channel, increases calcium level in T. molitor haemocytes which leading to changes in the expression of immune-related genes. On the basis of the results of the dsRNA experiment, our research also suggested that the link between Painless channel activity and immune pathways is likely mediated by Calcineurin, a calcium-activated serine/threonine phosphatase. Importantly, coinjection of AITC with Escherichia coli significantly improved beetle survival, indicating a functional role in host defense. The results of physiological experiments and phylogenetic analysis suggest that the modulation of Painless channel activity can be a valuable tool for pest control and large-scale T. molitor production.