RESUMO
Extracellular vesicles (EVs) or exovesicles are a heterogeneous group of small cell-derived membranous structures that carry complex cargoes including lipids, proteins, RNA, and DNA. Emerging evidence suggest that EVs secreted by kinetoplastid parasites play a cardinal role in the pathogenesis of diseases they cause, becoming valuable structures for understanding parasite-host interactions. Moreover, the characterization of EVs molecular cargo may provide a new approach to develop alternative tools for diagnosis and therapy of infectious diseases. EVs have a potential use as biomarkers since it contains a repertoire of DNA species that could be detected at different stages of infection by PCR-based assays. Here, we provide a detailed protocol for the isolation of Trypanosoma cruzi-derived EVs and purification of its DNA cargo for subsequent characterization. The methods described here are transferrable to other medically important parasites that are well adapted to grow in vitro and, therefore, suitable volume of EVs-containing supernatants can be obtained.
Assuntos
Vesículas Extracelulares , Parasitos , Trypanosoma cruzi , Animais , DNA , Interações Hospedeiro-Parasita , Trypanosoma cruzi/genéticaRESUMO
Leishmania parasite infections, termed the leishmaniases, cause significant global infectious disease burden. The lifecycle of the parasite embodies three main stages that require precise coordination of gene regulation to survive environmental shifts between sandfly and mammalian hosts. Constitutive transcription in kinetoplastid parasites means that gene regulation is overwhelmingly reliant on post-transcriptional mechanisms, yet strikingly few Leishmania trans-regulators are known. Using optimized crosslinking and deep, quantified mass spectrometry, we present a comprehensive analysis of 1400 mRNA binding proteins (mRBPs) and whole cell proteomes from the three main Leishmania lifecycle stages. Supporting the validity, although the crosslinked RBPome is magnitudes more enriched, the protein identities of the crosslinked and non-crosslinked RBPomes were nearly identical. Moreover, multiple candidate RBPs were endogenously tagged and found to associate with discrete mRNA target pools in a stage-specific manner. Results indicate that in L. mexicana parasites, mRNA levels are not a strong predictor of the whole cell expression or RNA binding potential of encoded proteins. Evidence includes a low correlation between transcript and corresponding protein expression and stage-specific variation in protein expression versus RNA binding potential. Unsurprisingly, RNA binding protein enrichment correlates strongly with relative replication efficiency of the specific lifecycle stage. Our study is the first to quantitatively define and compare the mRBPome of multiple stages in kinetoplastid parasites. It provides novel, in-depth insight into the trans-regulatory mRNA:Protein (mRNP) complexes that drive Leishmania parasite lifecycle progression.
Assuntos
Leishmania mexicana/genética , Parasitos/genética , Proteoma/metabolismo , Animais , Ontologia Genética , Estágios do Ciclo de Vida , Camundongos Endogâmicos BALB C , Análise de Componente Principal , Proteômica , Proteínas de Protozoários/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/metabolismo , Reprodutibilidade dos Testes , Transcriptoma/genéticaRESUMO
The intergenic region of spliced-leader (SL-IR) genes from 105 Trypanosoma cruzi I (Tc I) infected biological samples, culture isolates and stocks from 11 endemic countries, from Argentina to the USA were characterised, allowing identification of 76 genotypes with 54 polymorphic sites from 123 aligned sequences. On the basis of the microsatellite motif proposed by Herrera et al. (2007) to define four haplotypes in Colombia, we could classify these genotypes into four distinct Tc I SL-IR groups, three corresponding to the former haplotypes Ia (11 genotypes), Ib (11 genotypes) and Id (35 genotypes); and one novel group, Ie (19 genotypes). Genotypes harbouring the Tc Ic motif were not detected in our study. Tc Ia was associated with domestic cycles in southern and northern South America and sylvatic cycles in Central and North America. Tc Ib was found in all transmission cycles from Colombia. Tc Id was identified in all transmission cycles from Argentina and Colombia, including Chagas cardiomyopathy patients, sylvatic Brazilian samples and human cases from French Guiana, Panama and Venezuela. Tc Ie gathered five samples from domestic Triatoma infestans from northern Argentina, nine samples from wild Mepraia spinolai and Mepraia gajardoi and two chagasic patients from Chile and one from a Bolivian patient with chagasic reactivation. Mixed infections by Tc Ia+Tc Id, Tc Ia+Tc Ie and Tc Id+Tc Ie were detected in vector faeces and isolates from human and vector samples. In addition, Tc Ia and Tc Id were identified in different tissues from a heart transplanted Chagas cardiomyopathy patient with reactivation, denoting histotropism. Trypanosoma cruzi I SL-IR genotypes from parasites infecting Triatoma gerstaeckeri and Didelphis virginiana from USA, T. infestans from Paraguay, Rhodnius nasutus and Rhodnius neglectus from Brazil and M. spinolai and M. gajardoi from Chile are to our knowledge described for the first time.