scholarly journals The neuropeptide RhoprCCHamide2 inhibits serotonin-stimulated transcellular Na+ transport across the anterior midgut of the vector of Chagas disease Rhodnius prolixus

2021 ◽  
Author(s):  
Natalia Capriotti ◽  
Paula Gioino ◽  
Sheila Ons ◽  
Juan P. Ianowski
Keyword(s):  
Chagas Disease ◽  
Short Circuit ◽  
Ussing Chamber ◽  
Rhodnius Prolixus ◽  
Malpighian Tubules ◽  
Insect Vector ◽  
Na Channels ◽  
Atpase Inhibitor ◽  
Plasma Fraction ◽  
Anterior Midgut

Rhodnius prolixus is a blood-feeding insect vector of Tripanosoma cruzi, a protozoan parasite that causes Chagas' disease. During each blood meal the animals ingest large volumes of blood, that may be up to 12 times the unfed body mass. These blood meals impose a significant osmotic stress for the animals due to the hyposmotic condition of the ingested blood compared to the insect's haemolymph. Thus, the insect undergoes a massive postprandial diuresis that allows for the excretion of the plasma fraction of the blood in less than two hours. Diuresis is performed by the excretory system, consisting of the Malpighian tubules and gut, under the control of diuretic and antidiuretic factors. We investigated the ion transport machinery triggered by stimulation with the diuretic factor serotonin in the anterior midgut (i.e. crop) and the effect of the diuretic modulator RhoprCCHamide2. Ussing chamber assays revealed that serotonin-stimulated increase in transepithelial short circuit current (Isc) was more sensitive to the blockage with amiloride than EIPA, suggesting the involvement of Na+ channels. Incubation in Na+-free, but not Cl−-free saline, blocked the effect of serotonin on Isc. Moreover, treatment with NKCC and NCC blockers had no effect on fluid secretion but was blocked by amiloride. Blockage of Na+/K+-ATPase with ouabain inhibit Isc but the H+-ATPase inhibitor bafilomycin had no effect. The neuropeptide RhoprCCHamide2 diminished serotonin-stimulated Isc across the crop. The results suggest that Na+ undergoes active transport via an apical amiloride-sensitive Na+ channels and a basolateral ouabain-sensitive Na+/K+-ATPase while Cl− is transported through passive paracellular pathway.

The antidiuretic neurohormone RhoprCAPA-2 downregulates fluid transport across the anterior midgut in the blood-feeding insect Rhodnius prolixus

2010 ◽  
Vol 298 (3) ◽  
pp. R548-R557 ◽  
Author(s):  
Juan P. Ianowski ◽  
Jean-Paul Paluzzi ◽  
Victoria A. Te Brugge ◽  
Ian Orchard
Keyword(s):  
Fluid Transport ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Blood Feeding ◽  
Rhodnius Prolixus ◽  
Malpighian Tubules ◽  
Gene Encoding ◽  
Urine Formation ◽  
Terrestrial Insects ◽  
Anterior Midgut

Osmotic balance in insects is regulated by the excretory system, consisting of Malpighian tubules and the gut under the control of diuretic and antidiuretic factors. Terrestrial insects must conserve water, and antidiuresis is the norm, only interrupted by brief diuretic periods. Surprisingly, little is known about antidiuresis in insects. Two antidiuretic strategies have been described. The first antidiuretic mechanism involves the reabsorption of fluid from the primary urine in the hindgut. More recently, a second antidiuretic strategy was reported, consisting of inhibition of primary urine formation by the Malpighian tubules. Recently, we isolated, characterized, and cloned the gene encoding for the antidiuretic neurohormone (the neuropeptide RhoprCAPA-2) acting on the Malpighian tubules of Rhodnius prolixus . Here we describe a third, novel mechanism central to the antidiuretic strategy of R. prolixus , the inhibition of ion and fluid transport across the anterior midgut by RhoprCAPA-2. Our results show that RhoprCAPA-2 (1 μmol/l) reduces serotonin-stimulated fluid transport from 83 ± 11 to 12 ± 12 nl/min and equivalent short-circuit current from 20 ± 4 to 5 ± 0.7 μA/cm2 in diuretic hormone-stimulated anterior midgut. RhoprCAPA-2 appears to function independently of intracellular cGMP or Ca2+ in the midgut. Thus, the antidiuretic neurohormone RhoprCAPA-2 has multiple target tissues, and we hypothesize that RhoprCAPA-2 functions to coordinate the transport activity of the anterior midgut and Malpighian tubules so that the rate of fluid transport into the haemolymph by the anterior midgut matches the transport rate of Malpighian tubules to maintain the volume and ion composition of haemolymph.

Colonization of Rhodnius prolixus gut by Trypanosoma cruzi involves an extensive parasite killing

Parasitology ◽  
2016 ◽  
Vol 143 (4) ◽  
pp. 434-443 ◽  
Author(s):  
ROBERTA CARVALHO FERREIRA ◽  
RAFAEL LUIS KESSLER ◽  
MARCELO GUSTAVO LORENZO ◽  
RAFAELA MAGALHÃES MACEDO PAIM ◽  
LUCIANA DE LIMA FERREIRA ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Population Size ◽  
Chagas Disease ◽  
Intestinal Tract ◽  
Parasite Load ◽  
Rhodnius Prolixus ◽  
Insect Vector ◽  
Posterior Midgut ◽  
Development And Differentiation ◽  
Anterior Midgut

SUMMARYTrypanosoma cruzi, the etiological agent of Chagas disease, is ingested by triatomines during their bloodmeal on an infected mammal. Aiming to investigate the development and differentiation of T. cruzi inside the intestinal tract of Rhodnius prolixus at the beginning of infection we fed insects with cultured epimastigotes and blood trypomastigotes from infected mice to determine the amount of recovered parasites after ingestion. Approximately 20% of the ingested parasites was found in the insect anterior midgut (AM) 3 h after feeding. Interestingly, a significant reduction (80%) in the numbers of trypomastigotes was observed after 24 h of infection suggesting that parasites were killed in the AM. Moreover, few parasites were found in that intestinal portion after 96 h of infection. The evaluation of the numbers of parasites in the posterior midgut (PM) at the same periods showed a reduced parasite load, indicating that parasites were not moving from the AM. Additionally, incubation of blood trypomastigotes with extracts from R. prolixus AMs revealed that components of this tissue could induce significant death of T. cruzi. Finally, we observed that differentiation from trypomastigotes to epimastigotes is not completed in the AM; instead we suggest that trypomastigotes change to intermediary forms before their migration to the PM, where differentiation to epimastigotes takes place. The present work clarifies controversial points concerning T. cruzi development in insect vector, showing that parasite suffers a drastic decrease in population size before epimastigonesis accomplishment in PM.

Serotonin triggers cAMP and PKA-mediated intracellular calcium waves in Malpighian tubules of Rhodnius prolixus

2014 ◽  
Vol 307 (7) ◽  
pp. R828-R836 ◽  
Author(s):  
Paula Gioino ◽  
Brendan G. Murray ◽  
Juan P. Ianowski
Keyword(s):  
Second Messenger ◽  
Fluid Secretion ◽  
Rhodnius Prolixus ◽  
Malpighian Tubules ◽  
Insect Vector ◽  
Excess Water ◽  
Intracellular Ca ◽  
Single Meal ◽  
Hematophagous Insect

Rhodnius prolixus is a hematophagous insect vector of Chagas disease capable of ingesting up to 10 times its unfed body weight in blood in a single meal. The excess water and ions ingested with the meal are expelled through a rapid postprandial diuresis driven by the Malpighian tubules. Diuresis is triggered by at least two diuretic hormones, a CRF-related peptide and serotonin, which were traditionally believed to trigger cAMP as an intracellular second messenger. Recently, calcium has been suggested to act as a second messenger in serotonin-stimulated Malpighian tubules. Thus, we tested the role of calcium in serotonin-stimulated Malpighian tubules from R. prolixus. Our results show that serotonin triggers cAMP-mediated intracellular Ca2+ waves that were blocked by incubation in Ca2+-free saline containing the cell membrane-permeant Ca2+ chelator BAPTA-AM, or the PKA blocker H-89. Treatment with 8-Br-cAMP triggered Ca2+ waves that were blocked by H-89 and BAPTA-AM. Analysis of the secreted fluid in BAPTA-AM-treated tubules showed a 75% reduction in fluid secretion rate with increased K+ concentration, reduced Na+ concentration. Taken together, the results indicate that serotonin triggers cAMP and PKA-mediated Ca2+ waves that are required for maximal ion transport rate.

scholarly journals Pigmentation loci as markers for genome editing in the Chagas disease vector Rhodnius prolixus

2020 ◽  
Author(s):  
M. Berni ◽  
D. Bressan ◽  
Y. Simão ◽  
A. Julio ◽  
P. L. Oliveira ◽  
...  
Keyword(s):  
Genome Editing ◽  
Chagas Disease ◽  
Rhodnius Prolixus ◽  
Disease Spread ◽  
Great Promise ◽  
Insect Vector ◽  
Alternative Strategies ◽  
Primary Model ◽  
Genes Encoding ◽  
Eye Pigmentation

AbstractThe kissing bug Rhodnius prolixus is a major vector for Chagas disease in the Americas, and also considered as the primary model for functional studies. Prospective transgenic approaches and genome editing strategies hold great promise for controlling insect populations as well as disease propagation. In this context, identifying visible genetic markers for transgenic methodologies is of paramount importance to advance the field. Here we have identified and analyzed the function of putative cuticle and eye color genes by investigating the effect of gene knockdown on fertility, viability, and the generation of visible phenotypes. Synthesis of the dark, yellow and tan pigments present in the cuticle of most insects depends on the function of key genes encoding enzymes in the tyrosine pathway. Knockdown of the R. prolixus yellow and aaNAT/pro orthologs produces striking alterations in cuticle color. Surprisingly, knockdown of ebony does not generate visible phenotypes. Since loss of ebony function results in a dark cuticle in several insect orders, we conclude that R. prolixus evolved alternative strategies for cuticle coloration, possibly including the loss of a pigmentation function for an entire branch of the tyrosine pathway. Knockdown of the scarlet and brown genes - encoding ABC transporters - alters cuticle and eye pigmentation, implying that the transport of pigment into proper organelles is an important process both for cuticle and eye coloration in this species. Therefore, this analysis identifies for the first time potential visible markers for transgenesis in a hemipteran vector for a debilitating human disease.Author SummaryThe hemipteran Rhodnius prolixus - also known as a kissing bug - is a main vector transmitting the parasite Trypanosoma cruzi, the causative agent of Chagas disease, a debilitating infection estimated to affect more than 6 million people in Central and South America. In order to limit disease spread, an important measure is insect vector control. However, kissing bugs - like other insects - develop resistance to insecticides. Alternative strategies based on transgenesis and the recently developed CRISPR- based genome edition hold great promise to control vector population or generate parasite-resistant insects. For these approaches to be feasible in R. prolixus, it is critical to identify visible phenotypic markers. Here we identify and describe several genes controlling cuticle and eye pigmentation that are well-suited putative landing sites for transformation strategies. Among these, loss-of-function mutations in the ABC transporter encoding scarlet and the tyrosine pathway enzyme encoding aaNAT/pro generate striking and easily visible phenotypes. Importantly, the knockdown of these genes does not affect insect viability and fertility under laboratory conditions. Our results suggest that R. prolixus has developed alternative strategies for cuticle coloration involving the loss of an entire branch of tanning loci, while the other branch producing cuticle patterns by generating non-pigmented areas has gained critical importance.

scholarly journals Genome of Rhodnius prolixus, an insect vector of Chagas disease, reveals unique adaptations to hematophagy and parasite infection

2015 ◽  
Vol 112 (48) ◽  
pp. 14936-14941 ◽  
Author(s):  
Rafael D. Mesquita ◽  
Raquel J. Vionette-Amaral ◽  
Carl Lowenberger ◽  
Rolando Rivera-Pomar ◽  
Fernando A. Monteiro ◽  
...  
Keyword(s):  
Chagas Disease ◽  
Model Organism ◽  
Blood Feeding ◽  
Rhodnius Prolixus ◽  
Insect Vector ◽  
Protein Coding ◽  
Putative Gene ◽  
Imd Pathway ◽  
Genomic Analyses ◽  
Codon Use

Rhodnius prolixus not only has served as a model organism for the study of insect physiology, but also is a major vector of Chagas disease, an illness that affects approximately seven million people worldwide. We sequenced the genome of R. prolixus, generated assembled sequences covering 95% of the genome (∼702 Mb), including 15,456 putative protein-coding genes, and completed comprehensive genomic analyses of this obligate blood-feeding insect. Although immune-deficiency (IMD)-mediated immune responses were observed, R. prolixus putatively lacks key components of the IMD pathway, suggesting a reorganization of the canonical immune signaling network. Although both Toll and IMD effectors controlled intestinal microbiota, neither affected Trypanosoma cruzi, the causal agent of Chagas disease, implying the existence of evasion or tolerance mechanisms. R. prolixus has experienced an extensive loss of selenoprotein genes, with its repertoire reduced to only two proteins, one of which is a selenocysteine-based glutathione peroxidase, the first found in insects. The genome contained actively transcribed, horizontally transferred genes from Wolbachia sp., which showed evidence of codon use evolution toward the insect use pattern. Comparative protein analyses revealed many lineage-specific expansions and putative gene absences in R. prolixus, including tandem expansions of genes related to chemoreception, feeding, and digestion that possibly contributed to the evolution of a blood-feeding lifestyle. The genome assembly and these associated analyses provide critical information on the physiology and evolution of this important vector species and should be instrumental for the development of innovative disease control methods.

scholarly journals What happens after a blood meal? A transcriptome response from the main tissues involved in egg production in Rhodnius prolixus, an insect vector of Chagas disease

2020 ◽  
Author(s):  
Jimena Leyria ◽  
Ian Orchard ◽  
Angela B. Lange
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Chagas Disease ◽  
Blood Meal ◽  
Egg Production ◽  
Fat Body ◽  
Rhodnius Prolixus ◽  
Insect Vector ◽  
Blood Sucking ◽  
Epidemiological Impact

AbstractThe blood-sucking hemipteran Rhodnius prolixus is a vector of Chagas disease, one of the most neglected tropical diseases affecting several million people, mostly in Latin America. The blood meal is an event with a high epidemiological impact since in adult mated females it initiates the production of hundreds of eggs. By means of RNA-Sequencing (RNA-Seq) we have examined how a blood meal influences mRNA expression in the central nervous system (CNS), fat body and ovaries in order to promote egg production, focusing on tissue-specific responses under controlled nutritional conditions. We illustrate the cross talk between reproduction and a) lipids, proteins and trehalose metabolism, b) neuropeptide and neurohormonal signaling, and c) the immune system. Overall, our molecular evaluation confirms and supports previous studies and provides an invaluable molecular resource for future investigations on different tissues involved in successful reproductive events. Analyses like this can be used to increase the chances of developing novel strategies of vector population control by translational research, with less impact on the environment and more specificity for a particular organism.Author summaryThe blood-sucking hemipteran Rhodnius prolixus is one of the main vectors of Chagas disease. The blood meal is an event with a high epidemiological impact since in adult mated females, blood-gorging leads to the production of hundreds of eggs. This work describes an in-depth central nervous system (CNS), ovary and fat body transcriptome analysis, focusing on transcripts related to blood intake which may be relevant in promoting egg production. To date, the principle focus in Chagas disease prevention is on the elimination of triatomine vectors and their progeny. This work will serve as a starting point for initiating novel investigations on targets identified with a potential for use in vector control; for example using specific genes to generated symbiont-mediated RNAi, a powerful technology which provides a novel means in biocontrol against tropical disease vectors.

Ultrastructural Characterization of Malpighian Tubules of Rhodnius prolixus During the Insect's Feeding Cycle and Under Hyperosmotic Shock

2020 ◽  
Vol 129 (2) ◽  
pp. 189
Author(s):  
Jacenir Reis dos Santos-Mallet ◽  
Simone Patrícia Carneiro Freitas ◽  
Maria Luiza Ribeiro de Oliveira ◽  
Alice Helena Ricardo-Silva ◽  
Aníbal Gil Lopes ◽  
...  
Keyword(s):  
Rhodnius Prolixus ◽  
Malpighian Tubules ◽  
Hyperosmotic Shock ◽  
Ultrastructural Characterization ◽  
Feeding Cycle
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