The leishmaniases constitute neglected global public health problems that require adequate control measures, prophylactic clinical vaccines and effective and non-toxic drug treatments. In this study, we explored the potential of Leishmania infantum eukaryotic initiation factor (LieIF), an exosomal protein, as a novel anti-infective therapeutic molecule. More specifically, we assessed the efficacy of recombinant LieIF, in combination with recombinant IFN-γ, in eliminating intracellular L. donovani parasites in an in vitro macrophage model. J774A.1 macrophages were initially treated with LieIF/IFN-γ prior to in vitro infection with L. donovani stationary phase promastigotes (pre-infection treatment), and resistance to infection was observed 72 h after infection. J774A.1 macrophages were also treated with LieIF/IFN-γ after L. donovani infection (post-infection treatment), and resistance to infection was also observed at both time points tested (19 h and 72 h) after infection. To elucidate the LieIF/IFN-γ-induced mechanism(s) that mediate the reduction of intracellular parasite growth, we examined the generation of potent microbicidal molecules, such as nitric oxide (NO) and reactive oxygen species (ROS), within infected macrophages. Furthermore, macrophages pre-treated with LieIF/IFN-γ showed a clear up-regulation in macrophage inflammatory protein 1α (MIP-1α) as well as tumor necrosis factor alpha (TNF-α) expression. However, significant different protein levels were not detected. In addition, macrophages pre-treated with LieIF/IFN-γ combined with anti-TNF-α monoclonal antibody produced significantly lower amounts of ROS. These data suggest that during the pre-treatment state, LieIF induces intramacrophage parasite growth inhibition through the production of TNF-α, which induces microbicidal activity by stimulating NO and ROS production. The mechanisms of NO and ROS production when macrophages are treated with LieIF after infection are probably different. Overall, these results indicate that LieIF is a good candidate for use as an anti-leishmanial molecule.
Previously we showed that His-tagged, recombinant, Leishmania infantum eukaryotic initiation factor (LeIF) was both an RNA-dependent ATPase and an ATP-dependent RNA helicase in vitro, as described for other members of the DEAD-box helicase family. In addition, we showed that LeIF induces the production of IL-12, IL-10, and TNF-α by human monocytes. This study aims to characterize the cytokine-inducing activity in human monocytes of several proteins belonging to the DEAD-box family from mammals and yeast. All tested proteins contained the 11 conserved motifs (Q, I, Ia, GG Ib, II, III, IV, QxxR, V and VI) characteristic of DEAD-box proteins, but they have different biological functions and different percentages of identities with LeIF. We show that these mammalian or yeast recombinant proteins also are able to induce IL-12, IL-10 and TNF-α secretion by monocytes of healthy human subjects. This cytokine-inducing activity is proteinase K sensitive and polymyxin B resistant. Our results show that the induction of cytokines in human monocytes is not unique to the protein LeIF of Leishmania, and it suggests that the activity of certain DEAD-box proteins can be exploited as adjuvant and/or to direct immune responses towards a Th1 profile in vaccination or immunotherapy protocols.
Background. Digital systems for data management (DSDM) are considered nowadays of high importance in the field of biomedical sciences. Such systems ensure that data meet the standards of FAIR (Findability, Accessibility, Interoperability and Reusability). Our group is interested in implementing a DSDM for data collected from patients suspected of having cutaneous leishmaniasis (CL) in the frame of diagnostics evaluation. The data is collected in multiple sites and countries by different partners in the frame of a project supported by the USAID-NAS PEER program. We capitalized on the thorough clinical and field expertise of some partners to assess needs. Then, we further refined these needs consortium-wide to define the data to be collected by the clinicians and biologists during the data life cycle. This led to the development of a questionnaire form for data collection and the implementation of a web-based application, called Lesionia.Results. Based on the questionnaire, we developed Lesionia, a digital system for the management and the analysis of clinical and epidemiological data. It consists of a relational database and a web-based user interface (WUI). The database was conceived to be expandable to new collaborators and projects. It allows for data handling from the consented patient interview and sample collection to the samples storage and investigation. The WUI permits data entry, fetching, visualization and analysis. Rigorous controls on data entry were implemented to reduce discrepancies. It also offers a set of analysis tools that range from descriptive statistics to variable correlation analysis. Lesionia is accessible in a secure manner to all users of the consortium through a web browser connected to the Internet. Conclusion. Lesionia is a valuable tool for clinical and epidemiological data management. It is an open source software that can broadly serve the scientific community interested in studying, controlling, reporting and diagnosing CL and similar cutaneous diseases.
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