Disruption of insect immunity using analogs of the pleiotropic insect peptide hormone Neb-colloostatin: a nanotech approach for pest control II

Patryk Nowicki,Grzegorz Schroeder,Mariola Kuczer,Elżbieta Czarniewska

doi:10.1038/s41598-021-87878-5

Patryk Nowicki, Grzegorz Schroeder + Show 2 more

Open Access

https://doi.org/10.1038/s41598-021-87878-5

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Abstract

This work continues our studies on the pleiotropic activity of the insect peptide Neb-colloostatin in insects. In vivo immunological bioassays demonstrated that hemocytotoxic analogs of Neb-colloostatin injected into Tenebrio molitor significantly reduced the number of hemocytes in the hemolymph and impaired phagocytosis, nodulation and phenoloxidase activities in the insects. Among the analogs tested, [Ala1]-,[Val1]-, [Hyp4]- and [Ach4]-colloostatin were particularly potent in disrupting cellular immunity in larvae, pupae and adult insects. This result suggests that the most effective analogs showed increases in the bioactivity period in the hemolymph of insects when compared to Neb-colloostatin. Recently, we demonstrated that it is possible to introduce Neb-colloostatin through the cuticle of an insect into the hemolymph when the peptide is coupled with nanodiamonds. In this study, we showed that [Ala1]-, [Val1]-, [Hyp4]- and [Ach4]-colloostatin, when complexed with nanodiamonds, may also pass through the cuticle into the hemolymph and induce long-term impairments of immunity in T. molitor at all developmental stages. Studies on the tissue selectivity and effectiveness of Neb-colloostatin analogs and efficient methods for their introduction into insects may contribute to the development of eco-friendly pest control methods based on bioactive peptidomimetics.

Highlights

This work continues our studies on the pleiotropic activity of the insect peptide Neb-colloostatin in insects
Our findings indicate that significant long-term decreases in the number of circulating hemocytes in the hemolymph of larvae, pupae and adult insects caused by strong hemocytotoxic analogs of Neb-colloostatin result in significant reductions in the cellular and humoral immune responses of T. molitor at all studied developmental stages
Among the tested Neb-colloostatin analogs, we identified four active compounds, i.e., [Ala1], [Val1], [Hyp4]- and [Ach4]-colloostatin, which very effectively reduced the number of hemocytes circulating in the hemolymph and the short- and long-term cellular immune response in larvae, pupae and adult insects

Summary

Introduction

This work continues our studies on the pleiotropic activity of the insect peptide Neb-colloostatin in insects. Among the analogs tested, [Ala1]-,[Val1]-, [Hyp4]- and [Ach4]-colloostatin were potent in disrupting cellular immunity in larvae, pupae and adult insects This result suggests that the most effective analogs showed increases in the bioactivity period in the hemolymph of insects when compared to Neb-colloostatin. We showed that [Ala1]-, [Val1]-, [Hyp4]- and [Ach4]-colloostatin, when complexed with nanodiamonds, may pass through the cuticle into the hemolymph and induce long-term impairments of immunity in T. molitor at all developmental stages. One of the insect peptides that may be used in the future to reduce the number of pests is Neb-colloostatin (SIVPLGLPVPIGPIVVGPR), which is isolated from the ovaries of the flesh fly, Neobellieria bullata. The impact of these hemocytotoxic analogs on the immune response of insects has not yet been studied, and the increased hemocytotoxic activity resulting from these analogs suggests that they may strongly impair the innate immunity of insects; they may reduce the viability of insects more effectively than Neb-colloostatin can

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