Triplatin, a platelet aggregation inhibitor from the salivary gland of the triatomine vector of Chagas disease, binds to TXA(2) but does not interact with glycoprotein PVI

Functional aspects of evolution in a cluster of salivary protein genes from mosquitoes

The D7 proteins are highly expressed in the saliva of hematophagous Nematocera and bind biogenic amines and eicosanoid compounds produced by the host during blood feeding. These proteins are encoded by gene clusters expressing forms having one or two odorant-binding protein-like domains. Here we examine functional diversity within the D7 group in the genus Anopheles and make structural comparisons with D7 proteins from culicine mosquitoes in order to understand aspects of D7 functional evolution. Two domain long form (D7L) and one domain short form (D7S) proteins from anopheline and culicine mosquitoes were characterized to determine their ligand selectivity and binding pocket structures. We previously showed that a D7L protein from Anopheles stephensi, of the subgenus Cellia, could bind eicosanoids at a site in its N-terminal domain but could not bind biogenic amines in its C-terminal domain as does a D7L1 ortholog from the culicine species Aedes aegypti, raising the question of whether anopheline D7L proteins had lost their ability to bind biogenic amines. Here we find that D7L from anopheline species belonging to two other subgenera, Nyssorhynchus and Anopheles, can bind biogenic amines and have a structure much like the Ae. aegypti ortholog. The unusual D7L, D7L3, can also bind serotonin in the Cellia species An. gambiae. We also show through structural comparisons with culicine forms that the biogenic amine binding function of single domain D7S proteins in the genus Anopheles may have evolved through gene conversion of structurally similar proteins, which did not have biogenic amine binding capability. Collectively, the data indicate that D7L proteins had a biogenic amine and eicosanoid binding function in the common ancestor of anopheline and culicine mosquitoes, and that the D7S proteins may have acquired a biogenic amine binding function in anophelines through a gene conversion process.

Standardization and Validation of Fluorescence-Based Quantitative Assay to Study Human Platelet Adhesion to Extracellular-Matrix in a 384-Well Plate

Platelets play a crucial role in the immunological response and are involved in the pathological settings of vascular diseases, and their adhesion to the extracellular matrix is important to bring leukocytes close to the endothelial cells and to form and stabilize the thrombus. Currently there are several methods to study platelet adhesion; however, the optimal parameters to perform the assay vary among studies, which hinders their comparison and reproducibility. Here, a standardization and validation of a fluorescence-based quantitative adhesion assay to study platelet-ECM interaction in a high-throughput screening format is proposed. Our study confirms that fluorescence-based quantitative assays can be effectively used to detect platelet adhesion, in which BCECF-AM presents the highest sensitivity in comparison to other dyes.

ADP binding by the Culex quinquefasciatus mosquito D7 salivary protein enhances blood feeding on mammals

During blood-feeding, mosquito saliva is injected into the skin to facilitate blood meal acquisition. D7 proteins are among the most abundant components of the mosquito saliva. Here we report the ligand binding specificity and physiological relevance of two D7 long proteins from Culex quinquefasciatus mosquito, the vector of filaria parasites or West Nile viruses. CxD7L2 binds biogenic amines and eicosanoids. CxD7L1 exhibits high affinity for ADP and ATP, a binding capacity not reported in any D7. We solve the crystal structure of CxD7L1 in complex with ADP to 1.97 Å resolution. The binding pocket lies between the two protein domains, whereas all known D7s bind ligands either within the N- or the C-terminal domains. We demonstrate that these proteins inhibit hemostasis in ex vivo and in vivo experiments. Our results suggest that the ADP-binding function acquired by CxD7L1 evolved to enhance blood-feeding in mammals, where ADP plays a key role in platelet aggregation.

D7 proteins are highly abundant in the salivary glands of several blood feeding insects. Here, the authors study the ligand binding specificity and physiological roles of the mosquito D7 proteins CxD7L1 and CxD7L2, showing that CxD7L1 acquired ADP-binding properties to enhance blood feeding in mammals.

The Pharmacopea within Triatomine Salivary Glands

Triatomines are blood-feeding insects that prey on vertebrate hosts. Their saliva is largely responsible for their feeding success. The triatomine salivary content has been studied over the past decades, revealing multifunctional bioactive proteins targeting the host´s hemostasis and immune system. Recently, sequencing of salivary-gland mRNA libraries revealed increasingly complex and complete transcript databases that have been used to validate the expression of deduced proteins through proteomics. This review provides an insight into the journey of discovery and characterization of novel molecules in triatomine saliva.

Amine-binding properties of salivary yellow-related proteins in phlebotomine sand flies

The amine-binding properties of sand fly salivary yellow-related proteins (YRPs) were described only in Lutzomyia longipalpis sand flies. Here, we experimentally confirmed the kratagonist function of YRPs in the genus Phlebotomus. We utilized microscale thermophoresis technique to determine the amine-binding properties of YRPs in saliva of Phlebotomus perniciosus and P. orientalis, the Old-World vectors of visceral leishmaniases causative agents. Expressed and purified YRPs from three different sand fly species were tested for their interactions with various biogenic amines, including serotonin, histamine and catecholamines. Using the L. longipalpis YRP LJM11 as a control, we have demonstrated the comparability of the microscale thermophoresis method with conventional isothermal titration calorimetry described previously. By homology in silico modeling, we predicted the surface charge and both amino acids and hydrogen bonds of the amine-binding motifs to influence the binding affinities between closely related YRPs. All YRPs tested bound at least two biogenic amines, while the affinities differ both among and within species. Low affinity was observed for histamine. The salivary recombinant proteins rSP03B (P. perniciosus) and rPorASP4 (P. orientalis) showed high-affinity binding of serotonin, suggesting their capability to facilitate inhibition of the blood vessel contraction and platelet aggregation.

Anti-complement activity in salivary glands and midgut of Chagas disease vector, Panstrongylus megistus (Hemiptera, Triatominae)

The triatomine insect Panstrongylus megistus , one of the most important Chagas disease vectors in Brazil, presents salivary molecules pharmacologically active to counteract homeostatic responses from the host, including inhibitors of the human complement system, a major effector of immune responses. The aim of the present study was to investigate the effect of P. megistus salivary gland extract (SGE) on the complement system from different host species and characterize the inhibitory effect of SGE and intestinal contents on human complement. Glands and midguts from fourth instar nymphs were used. Hemolytic assays were performed with sheep erythrocytes as complement activators by using human, rats and chickens sera in the presence or absence of SGE. An ELISA assay was carried out detect deposition of the C3b component on IgG- or agarose-sensitized microplates, in the presence or absence of SGE or midgut contents. P. megistus SGE was able to significantly inhibit the complement of the three studied species (human, rat and chiken). Both, SGE and midgut contents inhibited C3b deposition in either the classical or the alternative pathways. As conclusions, SGE and midgut from P. megistus possess anti-complement activity. The inhibitors are effective against different host species and act on the initial steps of the complement system cascade. These inhibitors may have a role in blood feeding and Trypanosoma cruzi transmission by the vector.

An insight into the salivary gland and fat body transcriptome of Panstrongylus lignarius (Hemiptera: Heteroptera), the main vector of Chagas disease in Peru

Triatomines are hematophagous arthropod vectors of Trypanosoma cruzi, the causative agent of Chagas Disease. Panstrongylus lignarius, also known as Panstrongylus herreri, is considered one of the most versatile triatomines because it can parasitize different hosts, it is found in different habitats and countries, it has sylvatic, peridomestic and domestic behavior and it is a very important vector of Chagas disease, especially in Peru. Molecules produced and secreted by salivary glands and fat body are considered of important adaptational value for triatomines because, among other functions, they subvert the host haemostatic, inflammatory and immune systems and detoxify or protect them against environmental aggressors. In this context, the elucidation of the molecules produced by these tissues is highly valuable to understanding the ability of this species to adapt and transmit pathogens. Here, we use high-throughput sequencing techniques to assemble and describe the coding sequences resulting from the transcriptome of the fat body and salivary glands of P. lignarius. The final assembly of both transcriptomes together resulted in a total of 11,507 coding sequences (CDS), which were mapped from a total of 164,676,091 reads. The CDS were subdivided according to their 10 folds overexpression on salivary glands (513 CDS) or fat body (2073 CDS). Among the families of proteins found in the salivary glands, lipocalins were the most abundant. Other ubiquitous families of proteins present in other sialomes were also present in P. lignarius, including serine protease inhibitors, apyrase and antigen-5. The unique transcriptome of fat body showed proteins related to the metabolic function of this organ. Remarkably, nearly 20% of all reads mapped to transcripts coded by Triatoma virus. The data presented in this study improve the understanding on triatomines' salivary glands and fat body function and reveal important molecules used in the interplay between vectors and vertebrate hosts.

Exploring the molecular complexity of Triatoma dimidiata sialome

Triatoma dimidiata, a Chagas disease vector widely distributed along Central America, has great capability for domestic adaptation as the majority of specimens caught inside human dwellings or in peridomestic areas fed human blood. Exploring the salivary compounds that overcome host haemostatic and immune responses is of great scientific interest. Here, we provide a deeper insight into its salivary gland molecules. We used high-throughput RNA sequencing to examine in depth the T. dimidiata salivary gland transcriptome. From >51 million reads assembled, 92.21% are related to putative secreted proteins. Lipocalin is the most abundant gene family, confirming it is an expanded family in Triatoma genus salivary repertoire. Other putatively secreted members include phosphatases, odorant binding protein, hemolysin, proteases, protease inhibitors, antigen-5 and antimicrobial peptides. This work expands the previous set of functionally annotated sequences from T. dimidiata salivary glands available in NCBI from 388 to 3815. Additionally, we complemented the salivary analysis through proteomics (available data via ProteomeXchange with identifier PXD008510), disclosing the set complexity of 119 secreted proteins and validating the transcriptomic results. Our large-scale approach enriches the pharmacologically active molecules database and improves our knowledge about the complexity of salivary compounds from haematophagous vectors and their biological interactions.

SIGNIFICANCE

Several haematophagous triatomine species can transmit Trypanosoma cruzi, the etiological agent of Chagas disease. Due to the reemergence of this disease, new drugs for its prevention and treatment are considered priorities. For this reason, the knowledge of vector saliva emerges as relevant biological finding, contributing to the design of different strategies for vector control and disease transmission. Here we report the transcriptomic and proteomic compositions of the salivary glands (sialome) of the reduviid bug Triatoma dimidiata, a relevant Chagas disease vector in Central America. Our results are robust and disclosed unprecedented insights into the notable diversity of its salivary glands content, revealing relevant anti-haemostatic salivary gene families. Our work expands almost ten times the previous set of functionally annotated sequences from T. dimidiata salivary glands available in NCBI. Moreover, using an integrated transcriptomic and proteomic approach, we showed a correlation pattern of transcription and translation processes for the main gene families found, an important contribution to the research of triatomine sialomes. Furthermore, data generated here reinforces the secreted proteins encountered can greatly contribute for haematophagic habit, Trypanosoma cruzi transmission and development of therapeutic agent studies.

An Insight into the Triabin Protein Family of American Hematophagous Reduviids: Functional, Structural and Phylogenetic Analysis

A transcriptomic analysis of the saliva of T. pallidipennis together with a short proteomic analysis were carried out to reveal novel primary structures of the lipocalin/triabin protein families in this reduviid. Although triabins share some structural characteristics to lipocalins and they are classified as in the calcyn/lipocalin superfamily, triabins differ from lipocalins in the direction of β-strands in the general conformation of the β-barrel. The triabin protein family encompasses a wide variety of proteins, which disrupt the hemostasis of warm-blooded animals. Likewise, the function of proteins classified as triabins includes proteins that are carriers of small molecules, protease inhibitors, binders of specific cell-surface receptors as well as proteins that form complexes with other macromolecules. For example, triabin and pallidipin from the saliva of T. pallidipennis are thrombin and platelet aggregation inhibitors, respectively; triplatin from T. infestans binds to thromboxane A2; and nitrophorin from Rhodnius prolixus carries nitric oxide. Therefore, based on 42 new transcriptome sequences of triabins from the salivary glands of T. pallidipennis reported at present, and on triabin sequences of other American hematophagous reduviids already reported in the literature, subfamilies of triabins were proposed following phylogenetic analyses and functional characterization of triabin members. Eight subfamilies of proteins were recognized with known functions, which were the nitrophorin and amine binding proteins, Rhodnius prolixus aggregation inhibitor, triafestin, triatin, dipetalodipin and pallidipin, triplatin and infestilin, dimiconin and triabin, and procalin subfamilies. Interestingly, 70% of the analyzed sequences came from these eight subfamilies because there was no biological function associated with them, implying the existence of a vast number of proteins with potential novel biological activities.

Venoms of Heteropteran Insects: A Treasure Trove of Diverse Pharmacological Toolkits

The piercing-sucking mouthparts of the true bugs (Insecta: Hemiptera: Heteroptera) have allowed diversification from a plant-feeding ancestor into a wide range of trophic strategies that include predation and blood-feeding. Crucial to the success of each of these strategies is the injection of venom. Here we review the current state of knowledge with regard to heteropteran venoms. Predaceous species produce venoms that induce rapid paralysis and liquefaction. These venoms are powerfully insecticidal, and may cause paralysis or death when injected into vertebrates. Disulfide-rich peptides, bioactive phospholipids, small molecules such as N,N-dimethylaniline and 1,2,5-trithiepane, and toxic enzymes such as phospholipase A2, have been reported in predatory venoms. However, the detailed composition and molecular targets of predatory venoms are largely unknown. In contrast, recent research into blood-feeding heteropterans has revealed the structure and function of many protein and non-protein components that facilitate acquisition of blood meals. Blood-feeding venoms lack paralytic or liquefying activity but instead are cocktails of pharmacological modulators that disable the host haemostatic systems simultaneously at multiple points. The multiple ways venom is used by heteropterans suggests that further study will reveal heteropteran venom components with a wide range of bioactivities that may be recruited for use as bioinsecticides, human therapeutics, and pharmacological tools.

Impact of Insect Salivary Proteins in Blood Feeding, Host Immunity, Disease, and in the Development of Biomarkers for Vector Exposure

Functional genomic approaches based on expression of recombinant proteins linked to biochemical and disease model approaches resulted in the discovery of novel biological activities and the role some of these proteins play in disease transmission. Importantly, the expression of salivary proteins was recently shown to be affected by environmental factors and by the presence of the pathogen in the salivary gland. A practical application resulting from insect saliva research is the use of insect antigenic salivary protein as biomarkers of vector exposure in humans and animal reservoirs, an approach that is yielding interesting results in the field.

Salivary Thromboxane A2-Binding Proteins from Triatomine Vectors of Chagas Disease Inhibit Platelet-Mediated Neutrophil Extracellular Traps (NETs) Formation and Arterial Thrombosis

Background

The saliva of blood-feeding arthropods contains a notable diversity of molecules that target the hemostatic and immune systems of the host. Dipetalodipin and triplatin are triatomine salivary proteins that exhibit high affinity binding to prostanoids, such as TXA2, thus resulting in potent inhibitory effect on platelet aggregation in vitro. It was recently demonstrated that platelet-derived TXA2 mediates the formation of neutrophil extracellular traps (NETs), a newly recognized link between inflammation and thrombosis that promote thrombus growth and stability.

Methodology/Principal Findings

This study evaluated the ability of dipetalodipin and triplatin to block NETs formation in vitro. We also investigated the in vivo antithrombotic activity of TXA2 binding proteins by employing two murine models of experimental thrombosis. Remarkably, we observed that both inhibitors abolished the platelet-mediated formation of NETs in vitro. Dipetalodipin and triplatin significantly increased carotid artery occlusion time in a FeCl₃-induced injury model. Treatment with TXA2-binding proteins also protected mice from lethal pulmonary thromboembolism evoked by the intravenous injection of collagen and epinephrine. Effective antithrombotic doses of dipetalodipin and triplatin did not increase blood loss, which was estimated using the tail transection method.

Conclusions/Significance

Salivary TXA2-binding proteins, dipetalodipin and triplatin, are capable to prevent platelet-mediated NETs formation in vitro. This ability may contribute to the antithrombotic effects in vivo. Notably, both molecules inhibit arterial thrombosis without promoting excessive bleeding. Our results provide new insight into the antihemostatic effects of TXA2-binding proteins and may have important significance in elucidating the mechanisms of saliva to avoid host’s hemostatic responses and innate immune system.

Chagas disease is transmitted by the protozoan parasite Trypanosoma cruzi. The main form of transmission in endemic areas involves a life cycle in which blood-sucking triatomine vectors get infected by biting an infected animal or person. The saliva of blood-feeding arthropods contains a remarkable diversity of molecules that target the hemostatic and immune systems of the host. Thus, the systematic study and characterization of salivary proteins constitutes a strategy for identifying new exogenous compounds that may serve as prototypes for development of new drugs as well as strategies for vector control. Our group has studied the antihemostatic and antithrombotic properties of several exogenous inhibitors. In this report we demonstrated that the TXA2-binding proteins, dipetalodipin and triplatin, impair platelet-assisted formation of neutrophil extracellular traps (NETs). NETs have been described as web-like structures of DNA and proteins that play an important role in killing of pathogens. In addition, NETs have been recently implicated in thrombus formation. According to this, we demonstrate here that dipetalodipin and triplatin exhibit antithrombotic activity in two distinct in vivo mice models that are highly dependent on platelets. Remarkably, both molecules inhibited thrombosis without promoting excessive bleeding. Altogether, our results provide new insight into the antihemostatic effects of TXA2-binding proteins and may help to elucidate the mechanisms of saliva to avoid host’s hemostatic responses and innate immune system.

Plasmodium falciparum infection induces expression of a mosquito salivary protein (Agaphelin) that targets neutrophil function and inhibits thrombosis without impairing hemostasis

Background

Invasion of mosquito salivary glands (SGs) by Plasmodium falciparum sporozoites is an essential step in the malaria life cycle. How infection modulates gene expression, and affects hematophagy remains unclear.

Principal Findings

Using Affimetrix chip microarray, we found that at least 43 genes are differentially expressed in the glands of Plasmodium falciparum-infected Anopheles gambiae mosquitoes. Among the upregulated genes, one codes for Agaphelin, a 58-amino acid protein containing a single Kazal domain with a Leu in the P1 position. Agaphelin displays high homology to orthologs present in Aedes sp and Culex sp salivary glands, indicating an evolutionarily expanded family. Kinetics and surface plasmon resonance experiments determined that chemically synthesized Agaphelin behaves as a slow and tight inhibitor of neutrophil elastase (K_D∼10 nM), but does not affect other enzymes, nor promotes vasodilation, or exhibit antimicrobial activity. TAXIscan chamber assay revealed that Agaphelin inhibits neutrophil chemotaxis toward fMLP, affecting several parameter associated with cell migration. In addition, Agaphelin reduces paw edema formation and accumulation of tissue myeloperoxidase triggered by injection of carrageenan in mice. Agaphelin also blocks elastase/cathepsin-mediated platelet aggregation, abrogates elastase-mediated cleavage of tissue factor pathway inhibitor, and attenuates neutrophil-induced coagulation. Notably, Agaphelin inhibits neutrophil extracellular traps (NETs) formation and prevents FeCl₃-induced arterial thrombosis, without impairing hemostasis.

Conclusions

Blockade of neutrophil elastase emerges as a novel antihemostatic mechanism in hematophagy; it also supports the notion that neutrophils and the innate immune response are targets for antithrombotic therapy. In addition, Agaphelin is the first antihemostatic whose expression is induced by Plasmodium sp infection. These results suggest that an important interplay takes place in parasite-vector-host interactions.

Malaria is transmitted by Plasmodium falciparum-infected Anopheles gambiae mosquitoes. Salivary gland contributes to the development of the parasite by creating a favorable environment for the infection and facilitating blood feeding and reproduction of the vector. However, the molecular mechanism by which the vector salivary gland modulates parasite/host interactions is not understood. We discovered that infection of the mosquito salivary gland upregulates several genes; among them, one codes for a protease inhibitor named Agaphelin. Notably, Agaphelin was found to exhibit multiple antihemostatic functions by targeting elastase. As a result, it inhibits platelet function which is required for blood to clot, and it prevents cleavage of TFPI, an anticoagulant that has recently been found to play a crucial role in thrombus formation in vivo. Agaphelin also attenuates neutrophils chemotaxis and the release of Neutrophil Extracellular Traps. These results provide evidence that neutrophils serve as a link between coagulation and the innate immune response. Agaphelin also exhibits anti-inflammatory and antithrombotic effects in vivo. Furthermore, Agaphelin did not promote bleeding, suggesting that targeting neutrophil exhibits potential therapeutic value. Altogether, these results highlight that the interplay between parasite, vector and host is a dynamic process that contributes and sustains the interface among Plasmodium, Anopheles and humans.

The "Vampirome": Transcriptome and proteome analysis of the principal and accessory submaxillary glands of the vampire bat Desmodus rotundus, a vector of human rabies

Vampire bats are notorious for being the sole mammals that strictly feed on fresh blood for their survival. While their saliva has been historically associated with anticoagulants, only one antihemostatic (plasminogen activator) has been molecularly and functionally characterized. Here, RNAs from both principal and accessory submaxillary (submandibular) salivary glands of Desmodus rotundus were extracted, and ~200 million reads were sequenced by Illumina. The principal gland was enriched with plasminogen activators with fibrinolytic properties, members of lipocalin and secretoglobin families, which bind prohemostatic prostaglandins, and endonucleases, which cleave neutrophil-derived procoagulant NETs. Anticoagulant (tissue factor pathway inhibitor, TFPI), vasodilators (PACAP and C-natriuretic peptide), and metalloproteases (ADAMTS-1) were also abundantly expressed. Members of the TSG-6 (anti-inflammatory), antigen 5/CRISP, and CCL28-like (antimicrobial) protein families were also sequenced. Apyrases (which remove platelet agonist ADP), phosphatases (which degrade procoagulant polyphosphates), and sphingomyelinase were found at lower transcriptional levels. Accessory glands were enriched with antimicrobials (lysozyme, defensin, lactotransferrin) and protease inhibitors (TIL-domain, cystatin, Kazal). Mucins, heme-oxygenase, and IgG chains were present in both glands. Proteome analysis by nano LC-MS/MS confirmed that several transcripts are expressed in the glands. The database presented herein is accessible online at http://exon.niaid.nih.gov/transcriptome/D_rotundus/Supplemental-web.xlsx. These results reveal that bat saliva emerges as a novel source of modulators of vascular biology.

BIOLOGICAL SIGNIFICANCE

Vampire bat saliva emerges as a novel source of antihemostatics which modulate several aspects of vascular biology.

Lufaxin, a novel factor Xa inhibitor from the salivary gland of the sand fly Lutzomyia longipalpis blocks protease-activated receptor 2 activation and inhibits inflammation and thrombosis in vivo

OBJECTIVE

Blood-sucking arthropods' salivary glands contain a remarkable diversity of antihemostatics. The aim of the present study was to identify the unique salivary anticoagulant of the sand fly Lutzomyia longipalpis, which remained elusive for decades.

METHODS AND RESULTS

Several L. longipalpis salivary proteins were expressed in human embryonic kidney 293 cells and screened for inhibition of blood coagulation. A novel 32.4-kDa molecule, named Lufaxin, was identified as a slow, tight, noncompetitive, and reversible inhibitor of factor Xa (FXa). Notably, Lufaxin's primary sequence does not share similarity to any physiological or salivary inhibitors of coagulation reported to date. Lufaxin is specific for FXa and does not interact with FX, Dansyl-Glu-Gly-Arg-FXa, or 15 other enzymes. In addition, Lufaxin blocks prothrombinase and increases both prothrombin time and activated partial thromboplastin time. Surface plasmon resonance experiments revealed that FXa binds Lufaxin with an equilibrium constant ≈3 nM, and isothermal titration calorimetry determined a stoichiometry of 1:1. Lufaxin also prevents protease-activated receptor 2 activation by FXa in the MDA-MB-231 cell line and abrogates edema formation triggered by injection of FXa in the paw of mice. Moreover, Lufaxin prevents FeCl(3)-induced carotid artery thrombus formation and prolongs activated partial thromboplastin time ex vivo, implying that it works as an anticoagulant in vivo. Finally, salivary gland of sand flies was found to inhibit FXa and to interact with the enzyme.

CONCLUSIONS

Lufaxin belongs to a novel family of slow-tight FXa inhibitors, which display antithrombotic and anti-inflammatory activities. It is a useful tool to understand FXa structural features and its role in prohemostatic and proinflammatory events.

Interactome: Smart hematophagous triatomine salivary gland molecules counteract human hemostasis during meal acquisition

Human populations are constantly plagued by hematophagous insects' bites, in particular the triatomine insects that are vectors of the Trypanosoma cruzi agent in Chagas disease. The pharmacologically-active molecules present in the salivary glands of hematophagous insects are injected into the human skin to initiate acquisition of blood meals. Sets of vasodilators, anti-platelet aggregators, anti-coagulants, immunogenic polypeptides, anesthetics, odorants, antibiotics, and detoxifying molecules have been disclosed with the aid of proteomics and recombinant cDNA techniques. These molecules can provide insights about the insect-pathogen-host interactions essential for understanding the physiopathology of the insect bite. The data and information presented in this review aim for the development of new drugs to prevent insect bites and the insect-transmitted endemic of Chagas disease.