Jaburetox affects gene expression and enzyme activities in Rhodnius prolixus, a Chagas’ disease vector

• Published in: Acta tropica 2017-04, Vol.168, p.54-63
• Main Authors: Fruttero, Leonardo L., Moyetta, Natalia R., Krug, Monique Siebra, Broll, Valquiria, Grahl, Matheus V. Coste, Real-Guerra, Rafael, Stanisçuaski, Fernanda, Carlini, Celia R.
• Format: Article
• Language: English
• Subjects: Action mechanism; Animals; Chagas Disease - transmission; Chitin Synthase - genetics; Disease Vectors; Enzymatic pathways; Gene Expression Regulation, Enzymologic - drug effects; Insect Control - methods; Jaburetox; Nitric Oxide Synthase - genetics; Nitric Oxide Synthase - metabolism; Nucleotidyltransferases - genetics; Nucleotidyltransferases - metabolism; Rhodnius - drug effects; Rhodnius - enzymology; Rhodnius - genetics; Rhodnius prolixus; Urease - genetics; Urease - metabolism; Urease - pharmacology; Ureases
• ISSN: 0001-706X; 1873-6254
• DOI: 10.1016/j.actatropica.2017.01.009

[Display omitted] •Jaburetox, a urease-derived peptide, is lethal for insects of different orders.•The insect Rhodnius prolixus was used to study Jaburetox’s mechanism of action.•The peptide showed a high affinity towards the central nervous system.•Jaburetox induced changes in the enzymatic activity of NOS and UAP.•The peptide also led to changes in gene expression of NOS, UAP and chitin synthase. Jaburetox, a recombinant peptide of ∼11kDa derived from one of the Canavalia ensiformis (Jack Bean) urease isoforms, is toxic and lethal to insects belonging to different orders when administered orally or via injection. Previous findings indicated that Jaburetox acts on insects in a complex fashion, inhibiting diuresis and the transmembrane potential of Malpighian tubules, interfering with muscle contractility and affecting the immune system. In vitro, Jaburetox forms ionic channels and alters permeability of artificial lipid membranes. Moreover, recent data suggested that the central nervous system (CNS) is a target organ for ureases and Jaburetox. In this work, we employed biochemical, molecular and cellular approaches to explore the mode of action of Jaburetox using Rhodnius prolixus, one of the main Chagas’ disease vectors, as experimental model. In vitro incubations with fluorescently labeled Jaburetox indicated a high affinity of the peptide for the CNS but not for salivary glands (SG). The in vitro treatment of CNS or SG homogenates with Jaburetox partially inhibited the activity of nitric oxide synthase (NOS), thus disrupting nitrinergic signaling. This inhibitory effect was also observed in vivo (by feeding) for CNS but not for SG, implying differential modulation of NOS in these organs. The inhibition of NOS activity did not correlate to a decrease in expression of its mRNA, as assessed by qPCR. UDP-N-acetylglucosamine pyrophosphorylase (UAP), a key enzyme in chitin synthesis and glycosylation pathways and a known target of Jaburetox in insect CNS, was also affected in SG, with activation of the enzyme seen after both in vivo or in vitro treatments with the peptide. Unexpectedly, incubation of Jaburetox with a recombinant R. prolixus UAP had no effect on its activity, implying that the enzyme’s modulation by the peptide requires the participation of other factor(s) present in CNS or SG homogenates. Feeding Jaburetox to R. prolixus decreased the mRNA levels of UAP and chitin synthase, indicating a complex regulation exerted by the peptide on these enzy