Effect of DODAB Nano-Sized Cationic Bilayer Fragments against Leishmania amazonensis

The protein map of the protozoan parasite Leishmania (Leishmania) amazonensis, Leishmania (Viannia) braziliensis and Leishmania (Leishmania) infantum during growth phase transition and temperature stress

Leishmania parasites cause a spectrum of diseases termed leishmaniasis, which manifests in two main clinical forms, cutaneous and visceral leishmaniasis. Leishmania promastigotes transit from proliferative exponential to quiescent stationary phases inside the insect vector, a relevant step that recapitulates early molecular events of metacyclogenesis. During the insect blood meal of the mammalian hosts, the released parasites interact initially with the skin, an event marked by temperature changes. Deep knowledge on the molecular events activated during Leishmania-host interactions in each step is crucial to develop better therapies and to understand the pathogenesis. In this study, the proteomes of Leishmania (Leishmania) amazonensis (La), Leishmania (Viannia) braziliensis (Lb), and Leishmania (Leishmania) infantum (syn L. L. chagasi) (Lc) were analyzed using quantitative proteomics to uncover the proteome modulation in three different conditions related to growth phases and temperature shifts: 1) exponential phase (Exp); 2) stationary phase (Sta25) and; 3) stationary phase subjected to heat stress (Sta34). Functional validations were performed using orthogonal techniques, focusing on α-tubulin, gp63 and heat shock proteins (HSPs). Species-specific and condition-specific modulation highlights the plasticity of the Leishmania proteome, showing that pathways related to metabolism and cytoskeleton are significantly modulated from exponential to stationary growth phases, while protein folding, unfolded protein binding, signaling and microtubule-based movement were differentially altered during temperature shifts. This study provides an in-depth proteome analysis of three Leishmania spp., and contributes compelling evidence of the molecular alterations of these parasites in conditions mimicking the interaction of the parasites with the insect vector and vertebrate hosts. SIGNIFICANCE: Leishmaniasis disease manifests in two main clinical forms according to the infecting Leishmania species and host immune responses, cutaneous and visceral leishmaniasis. In Brazil, cutaneous leishmaniasis (CL) is associated with L. braziliensis and L. amazonensis, while visceral leishmaniasis, also called kala-azar, is caused by L. infantum. Leishmania parasites remodel their proteomes during growth phase transition and changes in their mileu imposed by the host, including temperature. In this study, we performed a quantitative mass spectrometry-based proteomics to compare the proteome of three New world Leishmania species, L. amazonensis (La), L. braziliensis (Lb) and L. infantum (syn L. chagasi) (Lc) in three conditions: a) exponential phase at 25 °C (Exp); b) stationary phase at 25 °C (Sta25) and; c) stationary phase subjected to temperature stress at 34 °C (Sta34). This study provides an in-depth proteome analysis of three Leishmania spp. with varying pathophysiological outcomes, and contributes compelling evidence of the molecular alterations of these parasites in conditions mimicking the interaction of the parasites with the insect vector and vertebrate hosts.

Supramolecular Nanostructures for Vaccines

Although this is an era of pandemics and many devastating diseases, this is also a time when bionanotechnology flourishes, illuminating a multidisciplinary field where vaccines are quickly becoming a balsam and a prevention against insidious plagues. In this work, we tried to gain and also give a deeper understanding on nanovaccines and their way of acting to prevent or cure cancer, infectious diseases, and diseases caused by parasites. Major nanoadjuvants and nanovaccines are temptatively exemplified trying to contextualize our own work and its relative importance to the field. The main properties for novel adjuvants seem to be the nanosize, the cationic character, and the biocompatibility, even if it is achieved in a low dose-dependent manner.

In Silico Characterization of Calcineurin from Pathogenic Obligate Intracellular Trypanosomatids: Potential New Biological Roles

Calcineurin (CaN) is present in all eukaryotic cells, including intracellular trypanosomatid parasites such as Trypanosoma cruzi (Tc) and Leishmania spp. (Lspp). In this study, we performed an in silico analysis of the CaN subunits, comparing them with the human (Hs) and looking their structure, post-translational mechanisms, subcellular distribution, interactors, and secretion potential. The differences in the structure of the domains suggest the existence of regulatory mechanisms and differential activity between these protozoa. Regulatory subunits are partially conserved, showing differences in their Ca²⁺-binding domains and myristoylation potential compared with human CaN. The subcellular distribution reveals that the catalytic subunits TcCaNA1, TcCaNA2, LsppCaNA1, LsppCaNA1_var, and LsppCaNA2 associate preferentially with the plasma membrane compared with the cytoplasmic location of HsCaNAα. For regulatory subunits, HsCaNB-1 and LsppCaNB associate preferentially with the nucleus and cytoplasm, and TcCaNB with chloroplast and cytoplasm. Calpain cleavage sites on CaNA suggest differential processing. CaNA and CaNB of these trypanosomatids have the potential to be secreted and could play a role in remote communication. Therefore, this background can be used to develop new drugs for protozoan pathogens that cause neglected disease.