Modified peptides and organic metabolites of cyanobacterial origin with antiplasmodial properties.

As etiological agents of malaria disease, Plasmodium spp. parasites are responsible for one of the most severe global health problems occurring in tropical regions of the world. This work involved compiling marine cyanobacteria metabolites reported in the scientific literature that exhibit antiplasmodial activity. Out of the 111 compounds mined and 106 tested, two showed antiplasmodial activity at very low concentrations, with IC50 at 0.1 and 1.5 nM (peptides: dolastatin 10 and lyngbyabellin A, 1.9% of total tested). Examples of chemical derivatives generated from natural cyanobacterial compounds to enhance antiplasmodial activity and Plasmodium selectivity can be found in successful findings from nostocarboline, eudistomin, and carmaphycin derivatives, while bastimolide derivatives have not yet been found. Overall, 57% of the reviewed compounds are peptides with modified residues producing interesting active moieties, such as α- and ß-epoxyketone in camaphycins. The remaining compounds belong to diverse chemical groups such as alkaloids, macrolides, polycyclic compounds, and halogenated compounds. The Dolastatin 10 and lyngbyabellin A, compounds with antiplasmodial high activity, are cytoskeletal disruptors with different protein targets.

Analysis of 26 STR loci (PowerPlex® Fusion 6C System) in a mestizo population from Mexico city.

BACKGROUND: Short tandem repeats (STRs) are the most widely used genetic markers in forensic genetics. Therefore, it is essential to document genetic population data of new kits designed for human identification purposes to enable laboratories to use these genetic systems to interpret and solve forensic casework. However, in Mexico, there are no studies with the PowerPlex Fusion 6C System, which includes 26 STRs (23 autosomal STRs and 3 Y-STRs). METHODS AND RESULTS: 600 DNA samples from Mexico City were subjected to genotyping using the PowerPlex Fusion 6C System. For autosomal STRs, 312 different alleles were observed. Combined PE and PD were 99.999999809866% and 99.99999999999999999999999818795%, respectively. Genetic distances and AMOVA test showed low but significant differentiation between Mexican populations. CONCLUSIONS: The results reported in this work demonstrate the efficacy of this system for human identification purposes in the population studied and justify its possible application in other Mexican Mestizo populations.

Activation of murine macrophages by membrane proteins from Tritrichomonas foetus grown on iron- and calcium-rich conditions.

Tritrichomonas foetus is a protozoan parasite that causes a venereal disease in cattle limiting reproduction by abortions and sterility. The immune response against this parasite is poorly understood. Since the iron and calcium ions are important regulators of the microenvironment of the urogenital tract in cattle, we decided to evaluate the role of these divalent cations on the antigenicity of membrane proteins of T. foetus on macrophage activation as one of the first inflammatory responses towards this pathogen. Colorimetric methods and ELISA were used to detect the nitric oxide and oxygen peroxide production and expression of cytokines in culture supernatant from macrophage incubated with membrane proteins from T. foetus cultured in iron- and calcium-rich conditions. qRT-PCR assays were used to evaluate the transcript expression of genes involved in the inflammatory response on the macrophages. The membrane proteins used for in vitro stimulation caused the up-regulation of the iNOS and NOX-2 genes as well as the generation of NO and H2 O2 in murine macrophages on a dependent way of the metal concentrations. Additionally, after stimulation, macrophages showed a considerable rise in pro-inflammatory cytokines and a downregulation of anti-inflammatory cytokines, as well as up-regulation in the transcription of the TLR4 and MyD88 genes. These data suggest that membrane proteins of T. foetus induced by iron and calcium can activate an inflammatory specific macrophage response via TLR4/MyD88 signalling pathway.

Exposure of Tritrichomonas foetus to sublethal doses of metronidazole induces a specific proinflammatory response in murine macrophages.

Tritrichomonas foetus is a flagellated parasite that primarily infects the reproductive tissues of livestock, causing bovine trichomoniasis. The cytoplasmic membrane of T. foetus contains various compounds that contribute to adherence, colonization, and pathogenicity. Metronidazole (MTZ) is the main treatment for trichomoniasis, but the emergence of drug-resistant strains is a concern due to improper use and dosing. T. foetus infection induces inflammation, and macrophages are key players in the immune response. However, our understanding of the host's immune response to T. foetus is limited, and the specific mechanisms underlying these responses are not well understood. This study aimed to investigate the impact of T. foetus surface proteins from trophozoites cultured under different sublethal MTZ conditions (MTZ-treated T. foetus MPs) on macrophage activation. By analyzing cytokine levels and gene expression in murine macrophages, we demonstrated that MTZ-treated T. foetus MPs induce a specific proinflammatory response. MTZ-treated T. foetus MPs-exposed macrophages exhibited a higher NO and H2 O2 production and overexpression of iNOS and NOX-2 genes in comparison to untreated T. foetus. Additionally, MTZ-treated T. foetus MPs triggered a significant induction of the proinflammatory cytokines IL-1ß, IL-6, TNF-α, and IFN-γ, as well as the overexpression of the TLR4, MyD88, and NF-κB genes on murine macrophages. The study aimed to unravel the immunological response and potential proinflammatory pathways involved in T. foetus infection and MTZ stress. Understanding the immune responses and mechanisms through which T. foetus surface proteins activate macrophages can contribute to the development of new therapeutic strategies for controlling bovine trichomoniasis.

Epigenetic Factors and ncRNAs in Testicular Cancer.

Testicular cancer is the most prevalent tumor among males aged 15 to 35, resulting in a significant number of newly diagnosed cases and fatalities annually. Non-coding RNAs (ncRNAs) have emerged as key regulators in various cellular processes and pathologies, including testicular cancer. Their involvement in gene regulation, coding, decoding, and overall gene expression control suggests their potential as targets for alternative treatment approaches for this type of cancer. Furthermore, epigenetic modifications, such as histone modifications, DNA methylation, and the regulation by microRNA (miRNA), have been implicated in testicular tumor progression and treatment response. Epigenetics may also offer critical insights for prognostic evaluation and targeted therapies in patients with testicular germ cell tumors (TGCT). This comprehensive review aims to present the latest discoveries regarding the involvement of some proteins and ncRNAs, mainly miRNAs and lncRNA, in the epigenetic aspect of testicular cancer, emphasizing their relevance in pathogenesis and their potential, given the fact that their specific expression holds promise for prognostic evaluation and targeted therapies.

Metastatic breast tumors downregulate miR-145 regulating the hypoxia-induced vasculogenic mimicry.

Tumor cells grow in three-dimensional (3D) channels-like structures denoted as vasculogenic mimicry (VM), which provides a route for nutrients and oxygen acquisition. VM is activated by hypoxia and associated with metastasis and poor prognosis. MetastamiRs are microRNAs regulating metastasis, however, if they control VM in breast cancer remains poorly understood. The aim of this study was to evaluate the expression of VM-associated microRNAs in tumors of metastatic breast cancer patients. Firstly, we constructed microRNAs/mRNAs coregulation networks using expression data from TCGA databases. Dozens of microRNAs regulating genes involved in VM and metastasis were found. Of these, we selected 10 microRNAs for further characterization. The presence of VM in histological samples from patients with or without metastasis was evaluated using CD31-/PAS+ immunophenotyping. Remarkably, data showed that VM was significantly increased in tumors from patients with metastasis in comparison with no-metastatic group. Gene expression analysis indicated that miR-145, miR-142-3p, miR-31, miR-148a, miR-200b-3p and miR-526b were downregulated in primary tumors from patients with metastatic disease and positive for VM. Moreover, modulated microRNAs showed a predictive clinical value in overall survival in a cohort (n=1262) of breast cancer patients. Of these, we evaluated the role of miR-145 in formation of hypoxia-induced 3D channels-like using an in vitro model that recapitulates the early stages of VM. Data showed that miR-145 mimics was able to abolish the VM development in both metastatic Hs578t and MDA-MB-231 breast cancer cells. In conclusion, manipulation of miR-145 levels may represent a therapeutic approach in metastatic breast cancer patients that developed VM.

The ovaries of ivermectin-resistant Rhipicephalus microplus strains display proteomic adaptations involving the induction of xenobiotic detoxification and structural remodeling mechanisms.

Controlling Rhipicephalus microplus is among the most significant challenges for livestock production worldwide. The indiscriminate use of acaricides stimulates the selection of resistant tick populations and is therefore ineffective. Understanding the molecular foundations of resistance could help inform the search for new alternatives for tick control. Although the ovary has been suggested as a relevant target organ for tick control, there are few existing studies that focus on tick ovarian tissue. Therefore, we conducted a comparative proteomic analysis on ovaries of R. microplus strains with differential resistance to ivermectin. In resistant ticks, we observed the over-accumulation of proteins involved in several biological processes, including translation, proteolysis, transport, cellular organization, differentiation, and xenobiotic detoxification. We also observed the accumulation of many structural and extracellular proteins such as papilin-like protein, which glycosylation increase its stability-based molecular modeling. Therefore, we propose that ovaries of ivermectin-resistant ticks overcome the negative impact of ivermectin through the activation of detoxification mechanisms and structural proteins associated with the remodeling of the ovary's extracellular matrix. SIGNIFICANCE: Understanding the molecular foundation of ivermectin resistance in Rhipicephalus microplus represents an essential step in cattle farming, which could provide clues and alternatives for tick control. Excessive use of chemicals like ivermectin allows the generation of resistant tick strains in different countries. However, limited molecular information is available concerning the tick's resistance to ivermectin. Detailed proteomics scrutiny in various tick organs will provide more comprehensive molecular information. Thus, we conducted an ovary comparative proteomic-based TMT-SPS-MS3 approach. We highlight in ivermectin-resistant ticks the over-accumulation of structural proteins and enzymes connected to detoxification mechanisms.

A Putative New Role of Tv-PSP1 Recognizes IRE and ERE Hairpin Structures from Trichomonas vaginalis.

To understand whether protein Tv-PSP1 from Trichomonas vaginalis recognizes mRNA parasite stem-loop structures, we conducted REMSA and intrinsic fluorescence assays. We found the recombinant Tv-PSP1 structure, determined with X-ray crystallography, showed unusual thermal stability of the quaternary structure, associated with a disulfide bridge CYS76-CYS104. To gain deeper insight into the Tv-PSP1 interaction with mRNA stem-loops (mRNAsl) and its relationship with thermal stability, we also used an integrated computational protocol that combined molecular dynamics simulations, docking assays, and binding energy calculations. Docking models allowed us to determine a putative contact surface interaction region between Tv-PSP1 and mRNAsl. We determined the contributions of these complexes to the binding free energy (ΔGb) in the electrostatic (ΔGelec) and nonelectrostatic (ΔGnon-elec) components using the Adaptive Poisson-Boltzmann Solver (APBS) program. We are the first, to the best of our knowledge, to show the interaction between Tv-PSP1 and the stem-loop structures of mRNA.

Natural marine products as antiprotozoal agents against amitochondrial parasites.

The goal of this work is to compile and discuss molecules of marine origin reported in the scientific literature with anti-parasitic activity against Trichomonas, Giardia, and Entamoeba, parasites responsible for diseases that are major global health problems, and Microsporidial parasites as an emerging problem. The presented data correspond to metabolites with anti-parasitic activity in human beings that have been isolated by chromatographic techniques from marine sources and structurally elucidated by spectroscopic and spectrometric procedures. We also highlight some semi-synthetic derivatives that have been successful in enhancing the activity of original compounds. The biological oceanic reservoir offers the possibility to discover new biologically active molecules as lead compounds to develop new drug candidates. The molecular variety is extensive and must be correctly explored and managed. Also, it will be necessary to take some actions to preserve the source species from extinction or overharvest (e.g., by cryopreservation of coral spermatozoa, oocytes, embryos, and larvae) and coordinate appropriate exploitation to increase the chemical knowledge of the natural products generated in the oceans. Additional initiatives such as the total synthesis of complex natural products and their derivatives can help to prevent overharvest of the marine ecosystems and at the same time contribute to the discovery of new molecules.

Comparative proteome analysis of the midgut of Rhipicephalus microplus (Acari: Ixodidae) strains with contrasting resistance to ivermectin reveals the activation of proteins involved in the detoxification metabolism.

Rhipicephalus microplus is the most serious tick parasite for the livestock industry in tropical and subtropical regions. A cost-effective control method to manage the infestation of this parasite involves the use of chemicals such as ivermectin. However, massive overuse of ivermectin over recent decades has selected for ivermectin-resistant populations of R. microplus. Here, we carried out a comparative proteomic analysis of the midgut of ivermectin-susceptible versus ivermectin-resistant ticks using tandem mass tags coupled to synchronous precursor selection. In susceptible ticks, there was an over-representation of proteins associated with blood digestion and anticoagulation. In contrast, resistant ticks exhibited an over-accumulation of proteins involved in phase I and phase II of the detoxification metabolism, including cytochrome P450, glutathione-S-transferase, and ABC transporters, as well as many ribosomal and other translation-related proteins. This information provides new clues about the mechanisms of ivermectin resistance in R. microplus as well as suggesting potential novel molecular targets to cope with ivermectin-resistant populations of R. microplus. SIGNIFICANCE: Cattle farming is an important primary economic activity for food production all over the globe. However, this activity also has detrimental environmental impacts, including the overuse of ivermectin and other chemicals used to control parasite infestations. The overuse of ivermectin selected for parasites with resistance to this chemical, including tick species like R. microplus. There has been extensive to understand the mechanisms that mediate ivermectin resistance in arthropods, but many gaps remain for the full comprehension of this phenomenon. Understanding the biochemistry behind ivermectin resistance could provide new alternatives to fight these parasites. We therefore consider that determining the metabolic mechanisms involved in ivermectin resistance is of great relevance. The comparative proteomic analysis here reported shows the relevance of the active detoxifying metabolism in the midgut of resistant ticks, which may be key for the development of novel control methods.

In Vitro Activation of Macrophages by an MHC Class II-restricted Trichomonas Vaginalis TvZIP8-derived Synthetic Peptide.

BACKGROUND: Macrophages play an important role in the inflammatory response towards pathogens and their effector functions depend on the mode of activation which is mediated by recognition of pathogen-associated molecular patterns, as peptides. Trichomonas vaginalis provokes an inflammatory response in the host in which macrophages are the first line of defense. This study aimed to analyze the effect of a specific peptide derived from the transporter TvZIP8 of T. vaginalis on the activation of macrophages. METHODS: An in silico approach based on computational prediction of epitopes was applied to detect potential murine MHC class II-restricted peptides from TvZIP8 that can activate macrophages and the immunomodulatory activity was evaluated by in vitro stimulation of murine macrophages. RESULTS: Based on binding scores, one peptide denominated TvZIP8-pep was selected for further analysis. In vitro stimulation with synthetic TvZIP8-pep triggered on murine macrophages the NO and H2O2 production and an overexpression of iNOS and NOX-2 genes. Also, a significant increase of pro-inflammatory cytokines: IL-1ß, IL-6, and TNF-α, as well as, overexpression of the TLR4, MyD88, and NF-κB genes and NF-κB activation were observed on macrophages after stimulation with TvZIP8-pep in vitro. Moreover, higher levels of IFN-γ were detected in co-cultures using CD4 + T cells with TvZIP8-pep-stimulated macrophages. CONCLUSION: These results support the potential of TvZIP8 as a promising antigen to stimulates a specific macrophage response against T. vaginalis, but further analyses are required to evaluate their possible potential as a novel antigen for immunodiagnosis and/or vaccine against trichomoniasis.

Antitrichomonal activity and docking analysis of thiazole derivatives as TvMP50 protease inhibitors.

Trichomoniasis, caused by the protozoan Trichomonas vaginalis, is the most prevalent non-viral sexually transmitted infection that affects over 170 million people worldwide. The only type of drug recommended for the therapeutic control of trichomoniasis is the 5-nitroimidazoles, although there have been reports of some undesirable side effects and clinical resistance. Hence, the need for the search for new tricomonicidal agents is necessary. In a previous work, we demonstrated that two 2-amino-4-aryl thiazole derivatives (ATZ-1 and ATZ-2) possess a portent antigiardial effect. In the current paper, we investigated the in vitro antitrichomonal activity of these thiazole compounds. Both ATZ-1 and ATZ-2 reduced the viability and growth of parasites in a dose-dependent manner, with an IC50 value of 0.15 µg/mL and 0.18 µg/mL, respectively. Furthermore, both thiazole compounds were able to decrease the proteolytic activity in T. vaginalis trophozoites compared with untreated parasites. Interestingly, a full proteolytic inhibition profile was observed in the 50-kDa region which was associated with the decreased expression of the gene that codes for the trichomonad protease TvMP50. The docking simulations predicted strong interactions of the thiazole compounds in the TvMP50 protease's active site, suggesting a possible role as protease inhibitors. Our results demonstrate the potential of 2-amino-4-aryl thiazole derivatives as trichomonicidal compounds and could be, mechanistically, involved in the inhibition of key trichomonad proteases.

Matrix metalloproteinases deregulation in amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the loss of upper and lower motor neurons that results in progressive paralysis and muscular atrophy. There are many molecules and genes involved in neuromuscular degeneration in ALS; among these, matrix metalloproteinases (MMPs). MMPs play an important role in the pathology of ALS, and MMP-1, 2, 3, and 9 might serve as disease progression markers. Tissue inhibitors of metalloproteinases (TIMPS) might also function as progression markers in ALS because they participate in regulating the proteolytic activity of MMPs. Moreover, a diversity of genes also plays a role in the pathogenesis of ALS; most MMPs-coding genes present variants related to the pathological proteolytic activity. This short review, however, will focus on the role of matrix metalloproteinases in ALS.

In silico analysis of putative metal response elements (MREs) in the zinc-responsive genes from Trichomonas vaginalis and the identification of novel palindromic MRE-like motif.

Zinc is an essential micronutrient that plays an important role as a co-factor to several proteins, including zinc-responsive transcription factors. Trichomonas vaginalis is able to survive in the presence of high zinc concentrations in the male urogenital tract. Several genes in T. vaginalis have been shown to respond to changes in zinc concentrations, however, the zinc-dependent mechanism remains undetermined. Recently, we identified in T. vaginalis the zinc finger protein, TvZNF1, which is an ortholog of the mammal metal transcription factor (MTF1). We searched for several of the zinc-responsive genes in T. vaginalis to determine whether if they contain metal response elements (MRE), cis-acting DNA elements that specifically bind MTF1. Six highly conserved over-represented sequence motifs (TvMREs), which share similarity with other eukaryotic MREs, were identified in the zinc-responsive genes in T. vaginalis. We also demonstrated that some of the TvMREs assemble as divalent complexes either as two closely spaced TvMREs or as two overlapping TvMREs forming a palindromic-like sequence: TGCC(N3)GGCA. Electrophoretic mobility shift assays were used to detect the zinc-dependent binding of TvZNF1 and nuclear proteins from T. vaginalis to this specific palindromic motif. Our results support a novel mechanism used by T. vaginalis for the transcriptional regulation of associated zinc-responsive genes through a MTF1/MRE-like system.

Pharmaco-epigenomics: On the Road of Translation Medicine.

Epigenomics refers to the study of genome-wide changes in epigenetic mechanisms including DNA methylation, histone modifications and non-coding RNAs expression. The alterations in normal DNA methylation and histone acetylation/deacetylation patterns lead to deregulated transcription and chromatin organization resulting in altered gene expression profiles that facilitates tumor development and progression. In consequence, novel therapeutic strategies aimed at reversing aberrant epigenetic marks in cancer cells have been developed and used in recent molecular studies and clinical trials. Pharmaco-epigenomics is a research area, which refers to the study of epigenome changes in cancer development and how chemotherapeutic agents can reverse these aberrant epigenetic marks by targeting the epigenetic machinery. Besides, the effects of genome-wide polymorphisms in populations leading to variations in drug response are also study subject of pharmaco-epigenomics and are being studied extensively in cancer. Recent findings showed that drug response could be largely influenced by the presence of aberrant epigenetic marks of the whole genome. This implies that biological pathways and cellular processes are under the impact of epigenome status. However, data about the relationship between drug response and the epigenomic variations is still scarce mainly because the epigenome is highly variable between individuals. The present chapter reviewed the advances on the epigenetics changes mainly DNA methylation and histones modifications on cervical and breast human cancers. A special emphasis in how they could be used as targets for the development and use of novel drugs in cancer therapy is delineated.

Immune Response of BALB/c Mice toward Putative Calcium Transporter Recombinant Protein of Trichomonas vaginalis.

Trichomoniasis is a common sexually transmitted infection caused by Trichomonas vaginalis, which actually does not exist a vaccine for control or prevention. Thus, the identification of new and potent immunogens in T. vaginalis, which can contribute to the development of a vaccine against this parasite, is necessary. Therefore, the aim of this work was to evaluate the potential of a recombinant Transient Receptor Potential-like channel of T. vaginalis (TvTRPV), as a promising immunogen in BALB/c mice. First, TvTRPV was cloned and expressed as a recombinant protein in Escherichia coli BL21 cells and purified by nickel affinity. Next, BALB/c mice were immunized and the antibody levels in mice serum and cytokines from the supernatant of macrophages and from co-culture systems were evaluated. Recombinant TvTRPV triggered high levels of specific total IgG in sera from the immunized mice. Also, a statistically significant increase of cytokines: IL-1ß, IL-6, and TNF-α after stimulation with the corresponding antigens in vitro, was identified. Moreover, co-cultures using CD4+ T cells from immunized mice were able to identify higher levels of IL-10 and IFN-γ. These results were useful to validate the immunogenicity of TvTRPV in BALB/c mice, where IL-10-IFN-γ-secreting cells could play a role in infection control, supporting the potential of TvTRPV as a promising target for vaccine against T. vaginalis.

Trichomonicidal activity of a new anthraquinone isolated from the roots of Morinda panamensis Seem.

Trichomoniasis, caused by the protozoan parasite Trichomonas vaginalis, is the most common nonviral sexually transmitted infection worldwide. Although drug treatment is available, unpleasant side effects and increased resistance to the nitroimidazole family have been documented. Hence, there is a need for the identification of new and safe therapeutic agents against T. vaginalis. Antimicrobial activity of anthraquinone compounds has been reported by a number of authors. The genus Morinda is well known for the diversity of anthraquinones with numerous biological activities. A new anthraquinone, lucidin-ω-isopropyl ether, was isolated from the roots of Morinda panamensis Seem. The structure of the compound was determined by 1 H and 13 C Nuclear Magnetic Resonance (NMR) analyses, in addition to comparison with literature reports. Using in vitro susceptibility assay, the half inhibitory concentration (IC50 ) of lucidin-ω-isopropyl ether for T. vaginalis (1.32 µg/mL) was found similar to that of metronidazole concentration tested (6 µM = 1.03 µg/mL). In addition, this anthraquinone was capable of inhibiting the parasite's ability to kill HeLa cells and decreased proteolytic activity of the proteinase TvMP50 from T. vaginalis. This was associated with the decreased expression of the mp50 gene. These results demonstrate the trichomonicidal potential by lucidin-ω-isopropyl ether. Further action-mode studies are necessary to elucidate the antiparasitic mechanism of this new anthraquinone to develop a more potent antitrichomonal agent.

Role of Matrix Metalloproteinases in Angiogenesis and Cancer.

During angiogenesis, new vessels emerge from existing endothelial lined vessels to promote the degradation of the vascular basement membrane and remodel the extracellular matrix (ECM), followed by endothelial cell migration, and proliferation and the new generation of matrix components. Matrix metalloproteinases (MMPs) participate in the disruption, tumor neovascularization, and subsequent metastasis while tissue inhibitors of metalloproteinases (TIMPs) downregulate the activity of these MMPs. Then, the angiogenic response can be directly or indirectly mediated by MMPs through the modulation of the balance between pro- and anti-angiogenic factors. This review analyzes recent knowledge on MMPs and their participation in angiogenesis.

Identification of a perchloric acid-soluble protein (PSP)-like ribonuclease from Trichomonas vaginalis.

A perchloric acid-soluble protein (PSP), named here tv-psp1, was identified in Trichomonas vaginalis. It is expressed under normal culture conditions according to expressed sequence tag (EST) analysis. On the other hand, Tv-PSP1 protein was identified by mass spectrometry with a 40% of identity to human PSP (p14.1). Polyclonal antibodies against recombinant Tv-PSP1 (rTv-PSP1) recognized a single band at 13.5 kDa in total protein parasite extract by SDS-PAGE and a high molecular weight band analyzed by native PAGE. Structural analysis of Tv-PSP1, using dynamic light scattering, size exclusion chromatography, and circular dichroism spectroscopy, showed a trimeric structure stable at 7 M urea with 38% α-helix and 14% ß-sheet in solution and a molecular weight of 40.5 kD. Tv-PSP1 models were used to perform dynamic simulations over 100 ns suggesting a stable homotrimeric structure. Tv-PSP1 was located in the nucleus, cytoplasm, and hydrogenosomes of T. vaginalis, and the in silico analysis by Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) showed interactions with RNA binding proteins. The preliminary results of RNA degradation analysis with the recombinant Tv-PSP1 showed RNA partial deterioration suggesting a possible putative ribonuclease function.

Chronic infection with Mycobacterium lepraemurium induces alterations in the hippocampus associated with memory loss.

Murine leprosy, caused by Mycobacterium lepraemurium (MLM), is a chronic disease that closely resembles human leprosy. Even though this disease does not directly involve the nervous system, we investigated a possible effect on working memory during this chronic infection in Balb/c mice. We evaluated alterations in the dorsal region of the hippocampus and measured peripheral levels of cytokines at 40, 80, and 120 days post-infection. To evaluate working memory, we used the T-maze while a morphometric analysis was conducted in the hippocampus regions CA1, CA2, CA3, and dentate gyrus (DG) to measure morphological changes. In addition, a neurochemical analysis was performed by HPLC. Our results show that, at 40 days post-infection, there was an increase in the bacillary load in the liver and spleen associated to increased levels of IL-4, working memory deterioration, and changes in hippocampal morphology, including degeneration in the four subregions analyzed. Also, we found a decrease in neurotransmitter levels at the same time of infection. Although MLM does not directly infect the nervous system, these findings suggest a possible functional link between the immune system and the central nervous system.