BUSCADOR RECOLECTA

Simple Summary Leishmaniasis is a group of parasitic diseases that affect humans and animals. Climate change and increased travel and migration have contributed to the spread of leishmaniasis in Europe, which may allow the introduction of new exotic Leishmania species or change the profile of known strains. Therefore, it is a priority to continue isolating and characterizing Leishmania strains from hosts. In this study, we analyzed and characterized two Leishmania isolates (NAV and TDL) obtained from naturally infected mammals (dogs). We identified Leishmania infantum parasites, the main agents responsible for the disease in Spain and Europe. We focused on the analysis of growth rate, treatment response, infection capacity, and gene expression, comparing these isolates with the widely studied strain L. infantum BCN 150. Considering that these isolates showed different profiles, both NAV and TDL could be useful for in vitro and in vivo assays that might shed some light on the biology of the parasite. Leishmaniasis is spreading in Europe, especially in endemic countries such as Italy and Spain, in part due to ongoing climate change and the increase in travel and migration. Although Leishmania infantum is the main agent responsible for this disease in humans and animals, other species and hybrids have been detected. This highlights the need to continue isolating and characterizing Leishmania strains from biological samples of infected hosts. In this study, we characterized the recently isolated parasites L. infantum NAV and L. infantum TDL, obtained from naturally infected mammals (dogs), and we compared them with the widely distributed and studied strain L. infantum BCN 150. Both NAV and TDL promastigotes showed a slower growth rate than BCN 150 and were significantly more sensitive to amphotericin B and miltefosine. Furthermore, the expression of the CYCA gene (involved in cell cycle and proliferation) was significantly downregulated in NAV and TDL isolates. On the other hand, CYC6 (implicated in treatment resistance) and APG9 (related to the recycling of protein under stress conditions and/or while undergoing a differentiation process and treatment resistance) levels were upregulated, compared to those measured in BCN 150. Both isolates displayed a higher infection capacity (>3 amastigotes per macrophage and >70% of infected macrophages) compared to controls (<2 amastigotes/cells and <50% of infected macrophages). Finally, a higher susceptibility to miltefosine treatment was observed in intracellular NAV and TDL amastigotes. In conclusion, TDL and NAV are novel Leishmania isolates that might be useful for in vitro and in vivo assays that will allow a better understanding of the parasite biology in Mediterranean areas.

Annexins (ANXs) exert different functions in cell biological and pathological processes and are thus known as double or multi-faceted proteins. These sophisticated proteins might express on both parasite structure and secretion and in parasite-infected host cells. In addition to the characterization of these pivotal proteins, describing their mechanism of action can be also fruitful in recognizing their roles in the pathogenesis of parasitic infections. Accordingly, this study presents the most prominent ANXs thus far identified and their relevant functions in parasites and infected host cells during pathogenesis, especially in the most important intracellular protozoan parasitic infections including leishmaniasis, toxoplasmosis, malaria and trypanosomiasis. The data provided in this study demonstrate that the helminth parasites most probably express and secret ANXs to develop pathogenesis while the modulation of the host-ANXs could be employed as a crucial strategy by intracellular protozoan parasites. Moreover, such data highlight that the use of analogs of both parasite and host ANX peptides (which mimic or regulate ANXs physiological functions through various strategies) might suggest novel therapeutic insights into the treatment of parasitic infections. Furthermore, due to the prominent immunoregulatory activities of ANXs during most parasitic infections and the expression levels of these proteins in some parasitic infected tissues, such multifunctional proteins might be also potentially relevant as vaccine and diagnostic biomarkers. We also suggest some prospects and insights that could be useful and applicable to form the basis of future experimental studies.

The search for new therapeutic targets and their implications in drug development remains an emerging scientific topic. BRCT-bearing proteins are found in Archaea, Bacteria, Eukarya, and viruses. They are traditionally involved in DNA repair, recombination, and cell cycle control. To carry out these functions, BRCT domains are able to interact with DNA and proteins. Moreover, such domains are also implicated in several pathogenic processes and malignancies including breast, ovarian, and lung cancer. Although these domains exhibit moderately conserved folding, their sequences show very low conservation. Interestingly, sequence variations among species are considered positive traits in the search for suitable therapeutic targets, since non-specific drug interactions might be reduced. These main characteristics of BRCT, as well as its critical implications in key biological processes in the cell, have prompted the study of these domains as therapeutic targets. This review explores the possible roles of BRCT domains as therapeutic targets for drug discovery. We describe their common structural features and relevant interactions and pathways, as well as their implications in pathologic processes. Drugs commonly used to target these domains are also presented. Finally, based on their structures, we describe new drug design possibilities using modern and innovative techniques.

The complement system exerts crucial functions both in innate immune responses and adaptive humoral immunity. This pivotal system plays a major role dealing with pathogen invasions including protozoan parasites. Different pathogens including parasites have developed sophisticated strategies to defend themselves against complement killing. Some of these strategies include the employment, mimicking or inhibition of host's complement regulatory proteins, leading to complement evasion. Therefore, parasites are proven to use the manipulation of the complement system to assist them during infection and persistence. Herein, we attempt to study the interaction's mechanisms of some prominent infectious protozoan parasites including Plasmodium, Toxoplasma, Trypanosoma, and Leishmania dealing with the complement system. Moreover, several crucial proteins that are expressed, recruited or hijacked by parasites and are involved in the modulation of the host's complement system are selected and their role for efficient complement killing or lysis evasion is discussed. In addition, parasite's complement regulatory proteins appear as plausible therapeutic and vaccine targets in protozoan parasitic infections. Accordingly, we also suggest some perspectives and insights useful in guiding future investigations.

Hypothesis/background: Tetronic is a family of four-armed amphiphilic block copolymers of polyethylene
oxide (PEO) and polypropylene oxide (PPO) that self-aggregate to form micelles and hydrogels. Due to
their temperature and pH-responsiveness, they are emerging as smart nanomaterials in the area of drug
delivery. Here we propose the use of Tetronic 1307 (T1307) as a nanocarrier of miltefosine (MF), a zwitterionic alkylphospholipid highly active against leishmaniasis, one of the most threating neglected tropical diseases. Given the amphiphilic nature of the drug, both surfactants can combine to form mixed
micelles, reducing the cytotoxicity of MF by lowering its dose and improving its internalization, hence
its antileishmanial effect.
Experiments: The structure of the T1307 micelles, MF micelles, mixed micelles and hydrogels, formed in
buffered solution (pH = 7.4) at different concentrations has been investigated in-depth by a combination
of small-angle neutron scattering (SANS), dynamic light scattering (DLS), fluorescence spectroscopy and
nuclear magnetic resonance methods (1D, 2D NOESY, and diffusion NMR). The cytotoxicity of the aggregates in macrophages has been assessed, as well as the antileishmanial activity in both Leishmania major
promastigotes and amastigotes.
Findings: T1307 and MF combine into mixed aggregates over a wide range of temperatures and compositions, forming ellipsoidal core–shell mixed micelles. The shell is highly hydrated and comprises most
of the PEO blocks, while the hydrophobic core contains the PO blocks and the MF along with a fraction of
EO and water molecules, depending on the molar ratio in the mixture. The combination with T1307
amplified the leishmanicidal activity of the drug against both forms of the parasite and dramatically
reduced drug cytotoxicity. T1307 micelles also showed a considerable leishmanicidal activity without
exhibiting macrophage toxicity. These results support the use of T1307 as a MF carrier for the treatment
of human and animal leishmaniasis, in its different clinical forms.

Variations on the processing conditions of conventional methods for polymeric film preparation may allow tuning certain properties. In this work, different casting surfaces and humidity are presented as variables to consider for cellulose acetate (CA) film preparation using conventional solution casting method. Specifically, borosilicate glass, soda-lime glass and Teflon (PTFE) dishes have been used for casting and their influence on various properties on CA films assessed. The surfaces of glass dishes are smooth, while PTFE surface has a pattern constituted by concentric channels of micro dimensions (as seen by optical microscope), which is adopted by cast films upon drying. The resulting patterned films are translucent while films produced using smooth surfaces are transparent. The effect of the environment humidity (35%, 55% and 75% RH) in the properties of the CA films during the evaporation of solvent from solution has been evaluated. Higher humidity produces smoother surfaces and increased crystallinity as shown by XRD and DSC; however, the wettability of the films does not seem to be influenced by this variable. Due to the specific morphology of the patterned films, changes in material opacity upon wetting are detected, from translucent to transparent, while the removal of water from the surface restores the translucency. This micropatterning effect that causes different visual appearance of the material can find use as a humidity sensor in food packaging applications.

Collagen-based polymers and their blends have attracted considerable interest for new
materials development due to their unique combination of biocompatibility, physical and mechanical
properties and durability. Leather, a modified natural biopolymer made from animal rawhide and
the first synthetic collagen-based polymer known since the dawn of civilization, combines all these
features. Rawhide is transformed into leather by tanning, a process in which the collagen is crosslinked with different agents to make it stronger and more durable and to prevent its decay. Research
on the development of environmentally friendly procedures and sustainable materials with higher
efficiency and lower costs is a rapidly growing field, and leather industry is not an exemption.
Chrome-tanned and vegetable-tanned (chromium-free) shavings from the leather industry present
a high content of organic matter, yet they are considered recalcitrant waste to be degraded by
microbiological processes like anaerobic digestion (AD), a solid technology to treat organic waste
in a circular economy framework. In this technology however, the solubilisation of organic solid
substrates is a significant challenge to improving the efficiency of the process. In this context, we
have investigated the process of microbial decomposition of leather wastes from the tannery industry
to search for the conditions that produce optimal solubilisation of organic matter. Chrome-tanned
and chromium-free leather shavings were pre-treated and anaerobically digested under different
temperature ranges (thermophilic–55 ◦C-, intermediate–42 ◦C- and mesophilic–35 ◦C) to evaluate
the effect on the solubilisation of the organic matter of the wastes. The results showed that the
presence of chromium significantly inhibited the solubilization (up to 60%) in the mesophilic and
intermediate ranges; this is the fastest and most efficient solubilization reached under thermophilic
conditions using the chromium-free leather shaving as substrates. The most suitable temperature
for the solubilization was the thermophilic regime (55 ◦C) for both chromium-free and chrometanned shavings. No significant differences were observed in the thermophilic anaerobic digestion
of chromium-free shavings when a pre-treatment was applied, since the solubilisation was already
high without pre-treatment. However, the pre-treatments significantly improved the solubilisation in
the mesophilic and intermediate configurations; the former pre-treatment was better suited in terms
of performance and cost-effectiveness compared to the thermophilic range. Thus, the solubilisation
of chromium-free tannery solid wastes can be significantly improved by applying appropriate pretreatments at lower temperature ranges; this is of utter importance when optimizing anaerobic
processes of recalcitrant organic wastes, with the added benefit of substantial energy savings in the
scaling up of the process in an optimised circular economy scenario., This research was funded by Navarra Government (Ayudas a Centros Tecnológicos y Organismos de Investigación program, Project PT025 AnAERObE) and by the Ministerio de Ciencia e Innovación of Spain, project PID2020-112713RB-C21.