Genes encoding defensins of important Chagas disease vectors used for phylogenetic studies

Araújo, Catarina Liane; Lima, Ana Carolina Bastos de; Jansen, Ana Maria; Galvão, Cléber; Jurberg, José; Costa, Jane; Waniek, Peter J.

doi:10.1007/s00436-015-4694-6

Cited by 12 publications

(4 citation statements)

References 73 publications

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“…In contrast, the NF- κ B inhibitor induced an increase in prol levels at 7 DAF. This discrepancy may be due to the fact that the R. prolixus defensins, and those of other triatomines such as Triatoma brasiliensis and Panstrongylus megistus , are regulated by NF- κ B TF ( Lopez et al, 2003 ; Waniek et al, 2009 ; de Araújo et al, 2015 ), whereas NF- κ B binding sites are absent in the prolixicin gene sequence, which appears to be regulated by GATA transcription factors ( Ursic-Bedoya et al, 2011 ). Further experiments are necessary to fully understand the signaling pathways that regulate prolixicin in R. prolixus and in other hemipterans.…”

Section: Discussionmentioning

confidence: 99%

The NF-κB Inhibitor, IMD-0354, Affects Immune Gene Expression, Bacterial Microbiota and Trypanosoma cruzi Infection in Rhodnius prolixus Midgut

et al. 2018

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Rhodnius prolixus is an insect vector of Trypanosoma cruzi, the causative agent of Chagas disease in Latin America. Nuclear factor-κB (NF-κB) transcription factors (TF) are conserved components of the innate immune system in several multicellular organisms including insects. The drug IMD-0354 [N-(3,5-bis-trifluoromethyl-phenyl)-5-chloro-2-hydroxy-benzamide] is a selective inhibitor of IκB kinases. It blocks IκBα phosphorylation thus preventing nuclear translocation of the NF-κb TF. In humans, NF-κB is involved in several biological processes such as inflammation, cell proliferation and immunity. In insects, the activation of the immune system upon microbial challenge can be controlled by signaling pathways such as the immune deficiency (IMD) and Toll, to combat infection. These activated pathways signal to downstream NF-κB TF to stimulate specific immune genes, triggering the synthesis of several molecules such as the antimicrobial peptides. In Drosophila melanogaster, the activation and regulation of NF-κB TF have been elucidated, while in triatomines these mechanisms are not fully understood Therefore, the present study investigated the effects of oral administration of the drug IMD-0354 on the R. prolixus immune response to challenge with bacteria and T. cruzi, as well as the impact on the gut bacterial microbiota. R. prolixus were fed with rabbit blood containing IMD-0354 and Escherichia coli, Staphylococcus aureus, or T. cruzi. The effects of IMD-0354 on insect mortality and antimicrobial activity in insect midgut samples, as well as the relative expression of R. prolixus immune genes were recorded. The bacterial microbiota was analyzed, and viable parasites were counted in insect midgut samples. The IMD-0354 treatment modulated antibacterial activity and the gene expression patterns of defensin A, defensin B, defensin C, and prolixicin, and the genes involved in the IMD and Toll pathways. Additionally, there was an increase of bacterial microbiota in treated insects. Insects treated with IMD-0354 and concomitantly infected with bacteria or T. cruzi through the blood meal had increased mortality, while the T. cruzi population in R. prolixus midgut was reduced. The inhibitory effect of IMD-0354 indicates the importance of NF-κB TF in the innate immune responses involved in the control of bacteria and parasite infections in the R. prolixus midgut.

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Section: Discussionmentioning

confidence: 99%

The NF-κB Inhibitor, IMD-0354, Affects Immune Gene Expression, Bacterial Microbiota and Trypanosoma cruzi Infection in Rhodnius prolixus Midgut

et al. 2018

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“…Several defensin-encoding genes have been identified in different triatomine species [ 11 , 37 , 59 – 61 ]. After the analysis of the primary defensin structure and the transcript abundance of defensin-encoding genes in T. brasiliensis , it was proposed that these peptides have different biological targets [ 60 ].…”

Section: Discussionmentioning

confidence: 99%

Impact of Trypanosoma cruzi on antimicrobial peptide gene expression and activity in the fat body and midgut of Rhodnius prolixus

et al. 2016

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BackgroundRhodnius prolixus is a major vector of Trypanosoma cruzi, the causative agent of Chagas disease in Latin America. In natural habitats, these insects are in contact with a variety of bacteria, fungi, virus and parasites that they acquire from both their environments and the blood of their hosts. Microorganism ingestion may trigger the synthesis of humoral immune factors, including antimicrobial peptides (AMPs). The objective of this study was to compare the expression levels of AMPs (defensins and prolixicin) in the different midgut compartments and the fat body of R. prolixus infected with different T. cruzi strains. The T. cruzi Dm 28c clone (TcI) successfully develops whereas Y strain (TcII) does not complete its life- cycle in R. prolixus. The relative AMP gene expressions were evaluated in the insect midgut and fat body infected on different days with the T. cruzi Dm 28c clone and the Y strain. The influence of the antibacterial activity on the intestinal microbiota was taken into account.MethodsThe presence of T. cruzi in the midgut of R. prolixus was analysed by optical microscope. The relative expression of the antimicrobial peptides encoding genes defensin (defA, defB, defC) and prolixicin (prol) was quantified by RT-qPCR. The antimicrobial activity of the AMPs against Staphylococcus aureus, Escherichia coli and Serratia marcescens were evaluated in vitro using turbidimetric tests with haemolymph, anterior and posterior midgut samples. Midgut bacteria were quantified using colony forming unit (CFU) assays and real time quantitative polymerase chain reaction (RT-qPCR).ResultsOur results showed that the infection of R. prolixus by the two different T. cruzi strains exhibited different temporal AMP induction profiles in the anterior and posterior midgut. Insects infected with T. cruzi Dm 28c exhibited an increase in defC and prol transcripts and a simultaneous reduction in the midgut cultivable bacteria population, Serratia marcescens and Rhodococcus rhodnii. In contrast, the T. cruzi Y strain neither induced AMP gene expression in the gut nor reduced the number of colony formation units in the anterior midgut. Beside the induction of a local immune response in the midgut after feeding R. prolixus with T. cruzi, a simultaneous systemic response was also detected in the fat body.ConclusionsR. prolixus AMP gene expressions and the cultivable midgut bacterial microbiota were modulated in distinct patterns, which depend on the T. cruzi genotype used for infection.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1398-4) contains supplementary material, which is available to authorized users.

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“…Additionally, the defensins of the Triatoma genus are clearly separated from the Rhodnius genus sequences, as previously described [ 26 ]. Furthermore, three sequences (Def 4.4, Def 4.5, and Def 4.6) in both the ML and Bayesian analyses are closely related to type-4 defensins of T. brasiliensis, T. sherlocki , and T. melanica , suggesting a close evolutionary relationship amongst them.…”

Section: Discussionmentioning

confidence: 99%

Variability of defensin genes from a Mexican endemic Triatominae: Triatoma (Meccus) pallidipennis (Hemiptera: Reduviidae)

Díaz-Garrido¹,

Sepúlveda-Robles

Martínez-Martínez³

et al. 2018

Bioscience Reports

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Chagas disease remains a serious health problem for countries where the most common mode of transmission is infection contracted from the feces of a Triatominae insect vector. In México, 32 species of Triatoma have been identified; amongst them, Triatoma (Meccus) pallidipennis is an endemic species reported to have high percentages of infection with T. cruzi. Defensins, cysteine-rich cationic peptides, are a family of antimicrobial peptides (AMPs); the synthesis of these molecules is crucial for insect’s immune defense. In the present study, the genes encoding defensins in T. pallidipennis were sequenced with the purpose of identifying the variability of these genes in a Mexican vector of T. cruzi. We found 12 different genes encoding three mature peptides, all of which had the typical folding of a functional insect defensin. In this work two Defensins type 1 and one type 4 were identified. The pro-peptide domain was highly variable and the mature peptide was not. This is the first report focus on variability of defensins from an epidemiologically important Triatoma in Mexico.

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Genes encoding defensins of important Chagas disease vectors used for phylogenetic studies

Cited by 12 publications

References 73 publications

The NF-κB Inhibitor, IMD-0354, Affects Immune Gene Expression, Bacterial Microbiota and Trypanosoma cruzi Infection in Rhodnius prolixus Midgut

The NF-κB Inhibitor, IMD-0354, Affects Immune Gene Expression, Bacterial Microbiota and Trypanosoma cruzi Infection in Rhodnius prolixus Midgut

Impact of Trypanosoma cruzi on antimicrobial peptide gene expression and activity in the fat body and midgut of Rhodnius prolixus

Variability of defensin genes from a Mexican endemic Triatominae: Triatoma (Meccus) pallidipennis (Hemiptera: Reduviidae)

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