Insights into the microRNA landscape of Rhodnius prolixus, a vector of Chagas disease.

The growing interest in microRNAs (miRNAs) over recent years has led to their characterization in numerous organisms. However, there is currently a lack of data available on miRNAs from triatomine bugs (Reduviidae: Triatominae), which are the vectors of the protozoan parasite Trypanosoma cruzi, the causative agent of Chagas disease. A comprehensive understanding of the molecular biology of vectors provides new insights into insect-host interactions and insect control approaches, which are key methods to prevent disease incidence in endemic areas. In this work, we describe the miRNome profiles from gut, hemolymph, and salivary gland tissues of the Rhodnius prolixus triatomine. Small RNA sequencing data revealed abundant expression of miRNAs, along with tRNA- and rRNA-derived fragments. Fifty-two mature miRNAs, previously reported in Ecdysozoa, were identified, including 39 ubiquitously expressed in the three tissues. Additionally, 112, 73, and 78 novel miRNAs were predicted in the gut, hemolymph, and salivary glands, respectively. In silico prediction showed that the top eight most highly expressed miRNAs from salivary glands potentially target human blood-expressed genes, suggesting that R. prolixus may modulate the host's gene expression at the bite site. This study provides the first characterization of miRNAs in a Triatominae species, shedding light on the role of these crucial regulatory molecules.

Liposomes Composed by Membrane Lipid Extracts from Macrophage Cell Line as a Delivery of the Trypanocidal N,N'-Squaramide 17 towards Trypanosoma cruzi.

Chagas is a neglected tropical disease caused by Trypanosoma cruzi, and affects about 25 million people worldwide. N, N'-Squaramide 17 (S) is a trypanocidal compound with relevant in vivo effectiveness. Here, we produced, characterized, and evaluated cytotoxic and trypanocidal effects of macrophage-mimetic liposomes from lipids extracted of RAW 264.7 cells to release S. As results, the average hydrodynamic diameter and Zeta potential of mimetic lipid membranes containing S (MLS) was 196.5 ± 11 nm and -61.43 ± 2.3 mV, respectively. Drug entrapment efficiency was 73.35% ± 2.05%. After a 72 h treatment, MLS was observed to be active against epimastigotes in vitro (IC50 = 15.85 ± 4.82 µM) and intracellular amastigotes (IC50 = 24.92 ± 4.80 µM). Also, it induced low cytotoxicity with CC50 of 1199.50 ± 1.22 µM towards VERO cells and of 1973.97 ± 5.98 µM in RAW 264.7. MLS also induced fissures in parasite membrane with a diameter of approximately 200 nm in epimastigotes. MLS showed low cytotoxicity in mammalian cells and high trypanocidal activity revealing this nanostructure a promising candidate for the development of Chagas disease treatment.

Ovicidal and Deleterious Effects of Cashew (Anacardium occidentale) Nut Shell Oil and Its Fractions on Musca domestica, Chrysomya megacephala, Anticarsia gemmatalis and Spodoptera frugiperda.

In this work, we evaluated the ovicidal activity and the deleterious effects of cashew (Anacardium occidentale) nut shell oil and its fractions on the development of Musca domestica and Chrysomya megacephala, important vectors of several diseases. The insecticidal effects of this plant were also measured on the first and second instar larvae of Anticarsia gemmatalis and Spodoptera frugiperda, soy and maize pests, respectively. The fly eggs and the crop pest insect larvae were exposed to the cashew (Anacardium occidentale) nut shell liquid (CNSL) and its fractions: technical CNSL, anacardic acid, cardanol and cardol. The results show that the cardol fraction, for both species of flies, presented the lowest lethal concentration with LC50 of 80.4 mg/L for M. domestica and 90.2 mg/L for C. megacephala. For the mortality of the larvae of A. gemmatalis and S. frugiperda, the most effective fraction was anacardic acid with LC50 of 295.1 mg/L and 318.4 mg/L, respectively. In all species, the mortality rate of the commercial compounds (cypermethrin 600 mg/L and temephos 2 mg/L) was higher than that of the evaluated compounds. Despite this, the results obtained suggest their potential in field trials, once the fractions of A. occidentale presented high mortality at low lethal concentrations in laboratory conditions, with the possibility of integrated use in the control of disease vectors and agricultural pests, employing ecofriendly compounds.

Larvicidal and pupicidal activities of eco-friendly phenolic lipid products from Anacardium occidentale nutshell against arbovirus vectors.

Aedes aegypti and Culex quinquefasciatus are vectors of diseases that constitute public health problems. The discovery of products capable of inhibiting their development which are less harmful to the environment would have a huge impact on vector control. Here, natural cashew nut shell liquid (CNSL), technical CNSL, anacardic acid, cardanol, and cardol were isolated from Anacardium occidentale and evaluated for larvicidal and pupicidal activity against Ae. aegypti and Cx. quinquefasciatus under laboratory and field conditions. The activities of phenol, resorcinol, salicylic acid, and pentadecane, commercial chemicals similar in structure to nut shell derivatives, were also evaluated. All of the fractions extracted from A. occidentale oil exerted larvicidal effects against both mosquito species (LC50 5.4-22.6 mg/L), and two of the aforementioned were effective against pupae (LC50 90.8-109.7 mg/L). Of all the fractions tested, cardol demonstrated the strongest larvicidal and pupicidal effects and presented the most prolonged residual activity against the larvae and pupae of Ae. aegypti and Cx. quinquefasciatus under field conditions. This study suggests that A. occidentale nut shell derivatives are sustainable and promising candidates for the development of novel insecticides to overcome the problem of harmful chemical insecticides.

Triatomines: Trypanosomatids, Bacteria, and Viruses Potential Vectors?

Triatominae bugs are the vectors of Chagas disease, a major concern to public health especially in Latin America, where vector-borne Chagas disease has undergone resurgence due mainly to diminished triatomine control in many endemic municipalities. Although the majority of Triatominae species occurs in the Americas, species belonging to the genus Linshcosteus occur in India, and species belonging to the Triatoma rubrofasciata complex have been also identified in Africa, the Middle East, South-East Asia, and in the Western Pacific. Not all of Triatominae species have been found to be infected with Trypanosoma cruzi, but the possibility of establishing vector transmission to areas where Chagas disease was previously non-endemic has increased with global population mobility. Additionally, the worldwide distribution of triatomines is concerning, as they are able to enter in contact and harbor other pathogens, leading us to wonder if they would have competence and capacity to transmit them to humans during the bite or after successful blood feeding, spreading other infectious diseases. In this review, we searched the literature for infectious agents transmitted to humans by Triatominae. There are reports suggesting that triatomines may be competent vectors for pathogens such as Serratia marcescens, Bartonella, and Mycobacterium leprae, and that triatomine infection with other microrganisms may interfere with triatomine-T. cruzi interactions, altering their competence and possibly their capacity to transmit Chagas disease.

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.

Brazilian Cerrado Qualea grandiflora Mart. Leaves Exhibit Antiplasmodial and Trypanocidal Activities In vitro.

BACKGROUND: The rapid spread of drug-resistant strains of protozoan parasites required the urgent need for new effective drugs. Natural products offer a variety of chemical structures, which make them a valuable source of lead compounds for the development of such new drugs. Cerrado is the second largest biome in Brazil and has the richest flora of all the world savannahs. We selected Qualea grandiflora, a plant species known for its proprieties in folk medicine and its antibacterial activity. OBJECTIVE: However, its antiprotozoal activity was not yet explored. MATERIALS AND METHODS: We investigated the activities of fractions from the ethyl acetate extract of Q. grandiflora leaves against human life forms of Plasmodium falciparum, Trypanosoma cruzi, and Trypanosoma brucei gambiense, and for its cytotoxicity upon the rat L6-myoblast cell line. Ten fractions were produced by ethyl acetate:hexane chromatography. RESULTS AND CONCLUSION: The fractions showed no cytotoxicity against L-6 cells (IC50 > 100 µg/mL) and no hemolysis propriety. Three fractions had a moderate activity against P. falciparum, anyone was active against T. cruzi but four fractions demonstrated a high activity against bloodstream forms of T. brucei gambiense (8.0< IC50 <15 µg/mL). Identification and characterization of the active compounds are currently under investigation. SUMMARY: Qualea grandiflora is an endemic tree of the Brazilian Cerrado, which presents medicinal propertiesTen fractions of the ethyl acetate extract of Q. grandiflora leaves were assessed against Plasmodium falciparum, Trypanosoma Cruzi, and Trypanosoma brucei gambienseNo fraction showed relevant cytotoxicity and hemolysis activityAll the fractions presented antiplasmodial and trypanocidal activitiesThree fractions with moderate antiplasmodial activity (49< IC50 <56 µg/mL)Four fractions with high activity against bloodstream forms of T. brucei gambiense (8.0< IC50 <15 µg/mL). Abbreviations used: CQ: Chloroquine, DMSO: Dimethyl sulfoxide, HEPES: 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid, HMI: Modified Iscove's medium, IC50: Concentration inhibiting 50% of parasite growth, IC90: Concentration inhibiting 90% of parasite growth, MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, RPMI: Roswell Park Memorial Institute, SD: Standard deviation, SI: Ratio of cytotoxicity to biological activity - TC50/IC50, TC50: Concentration causing 50% of cell growth inhibition, TC90: Concentration causing 90% of cell growth inhibition, TLC: Thin-layer chromatography.

Analysis of the Paracoccidioides brasiliensis triosephosphate isomerase suggests the potential for adhesin function.

Paracoccidioides brasiliensis is an important fungal pathogen. The disease it causes, paracoccidioidomycosis (PCM), ranges from localized pulmonary infection to systemic processes that endanger the life of the patient. Paracoccidioides brasiliensis adhesion to host tissues contributes to its virulence, but we know relatively little about molecules and the molecular mechanisms governing fungal adhesion to mammalian cells. Triosephosphate isomerase (TPI: EC 5.3.1.1) of P. brasiliensis (PbTPI) is a fungal antigen characterized by microsequencing of peptides. The protein, which is predominantly expressed in the yeast parasitic phase, localizes at the cell wall and in the cytoplasmic compartment. TPI and the respective polyclonal antibody produced against this protein inhibited the interaction of P. brasiliensis to in vitro cultured epithelial cells. TPI binds preferentially to laminin, as determined by peptide inhibition assays. Collectively, these results suggest that TPI is required for interactions between P. brasiliensis and extracellular matrix molecules such as laminin and that this interaction may play an important role in the fungal adherence and invasion of host cells.