Leishmania major telomerase RNA knockout: From altered cell proliferation to decreased parasite infectivity.

This study focuses on the biological impacts of deleting the telomerase RNA from Leishmania major (LeishTER), a parasite responsible for causing leishmaniases, for which no effective treatment or prevention is available. TER is a critical player in the telomerase ribonucleoprotein complex, containing the template sequence copied by the reverse transcriptase component during telomere elongation. The success of knocking out both LeishTER alleles was confirmed, and no off-targets were detected.

Comparison of Sampling Procedures for the Molecular Diagnosis of Leishmaniases.

The present work evaluates sampling protocols, storage procedures, and DNA purification methods for Leishmania spp. detection and quantification in different biological samples. The efficiency of three preservation solutions, a phosphate buffer solution, an ethylenediaminetetraacetic acid (EDTA) buffer solution, and 70% ethanol, was compared in combination with three DNA extraction protocols: a commercial silica column kit, salting-out protein precipitation, and organic extraction with phenol-chloroform.

Reporter gene systems: A powerful tool for studies.

Protozoan parasites of the genus are responsible for leishmaniases, one of the most important anthropozoonotic diseases affecting millions of people worldwide. To date, there are no approved vaccines against leishmaniases for humans. At present, available treatment options lack specificity, which may lead to drug resistance and often cause adverse effects.

Finding Correlations Between mRNA and Protein Levels in Development: Is There a Discrepancy?

Multiple genes and proteins have been identified as differentially expressed in the stages of the  life cycle. The differentiation processes are implicated in specific transcriptional and proteomic adjustments driven by gene expression regulation mechanisms. parasites lack gene-specific transcriptional control, and gene expression regulation mostly depends on posttranscriptional mechanisms.

Dual transcriptome analysis reveals differential gene expression modulation influenced by arginase and host genetic background.

The outcome of infection is strongly influenced by the host's genetic background. BALB/c mice are susceptible to infection, while C57BL/6 mice show discrete resistance. Central to the fate of the infection is the availability of l-arginine and the related metabolic processes in the host and parasite.

In Vivo Infection with Leishmania amazonensis to Evaluate Parasite Virulence in Mice.

Leishmania spp. are protozoan parasites that cause leishmaniases, diseases that present a wide spectrum of clinical manifestations from cutaneous to visceral lesions. Currently, 12 million people are estimated to be infected with Leishmania worldwide and over 1 billion people live at the risk of infection.

Author Correction: Differential immune response modulation in early Leishmania amazonensis infection of BALB/c and C57BL/6 macrophages based on transcriptome profiles.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Differential immune response modulation in early Leishmania amazonensis infection of BALB/c and C57BL/6 macrophages based on transcriptome profiles.

The fate of Leishmania infection can be strongly influenced by the host genetic background. In this work, we describe gene expression modulation of the immune system based on dual global transcriptome profiles of bone marrow-derived macrophages (BMDMs) from BALB/c and C57BL/6 mice infected with Leishmania amazonensis. A total of 12,641 host transcripts were identified according to the alignment to the Mus musculus genome.

Metabolomic Profile of BALB/c Macrophages Infected with : Deciphering L-Arginine Metabolism.

Background: Leishmaniases are neglected tropical diseases that are caused by , being endemic worldwide. L-arginine is an essential amino acid that is required for polyamines production on mammal cells. During infection of macrophages, L-arginine is used by host and parasite arginase to produce polyamines, leading to parasite survival; or, by nitric oxide synthase 2 to produce nitric oxide leading to parasite killing.

The impact of arginase activity on virulence factors of Leishmania amazonensis.

The outcome of Leishmania infection depends on the parasite species and the host immune response. Virulence factors have been extensively studied over the years in an effort to find efficient vaccines and/or treatments for Leishmania infection. Arginase activity in Leishmania has been described as an essential player for the polyamines pathway, impacting parasite replication and infectivity.

Melatonin and Infection Altered miR-294, miR-30e, and miR-302d Impacting on , , and 2 Expression.

Leishmaniases are neglected diseases that cause a large spectrum of clinical manifestations, from cutaneous to visceral lesions. The initial steps of the inflammatory response involve the phagocytosis of and the parasite replication inside the macrophage phagolysosome. Melatonin, the darkness-signaling hormone, is involved in modulation of macrophage activation during infectious diseases, controlling the inflammatory response against parasites.

Toll-Like Receptor and miRNA-let-7e Expression Alter the Inflammatory Response in -Infected Macrophages.

Parasite recognition by Toll-like receptors (TLRs) contributes to macrophage activation and subsequent control of infection through the coordinated production of pro-inflammatory and microbicidal effector molecules. The modulation of microRNA (miRNA) expression by infection potentially mediates the post-transcriptional regulation of the expression of genes involved in leishmanicidal activity. Here, the contribution of TLR signaling to the miRNA profile and gene expression was evaluated in -infected murine macrophages.

Amino acid permease 3 (aap3) coding sequence as a target for Leishmania identification and diagnosis of leishmaniases using high resolution melting analysis.

Background: The leishmaniases comprise a spectrum of clinical manifestations caused by different species of Leishmania. Identification of species is important for diagnosis, treatment and follow-up management. However, there is no gold standard for species identification.

Arginase expression modulates nitric oxide production in Leishmania (Leishmania) amazonensis.

Background: Arginase is an enzyme that converts L-arginine to urea and L-ornithine, an essential substrate for the polyamine pathway supporting Leishmania (Leishmania) amazonensis replication and its survival in the mammalian host. L-arginine is also the substrate of macrophage nitric oxide synthase 2 (NOS2) to produce nitric oxide (NO) that kills the parasite. This competition can define the fate of Leishmania infection.

RNA-seq transcriptional profiling of Leishmania amazonensis reveals an arginase-dependent gene expression regulation.

Background: Leishmania is a protozoan parasite that alternates its life cycle between the sand-fly vector and the mammalian host. This alternation involves environmental changes and leads the parasite to dynamic modifications in morphology, metabolism, cellular signaling and regulation of gene expression to allow for a rapid adaptation to new conditions. The L-arginine pathway in L.

L-arginine availability and arginase activity: Characterization of amino acid permease 3 in Leishmania amazonensis.

Background: Leishmania uses the amino acid L-arginine as a substrate for arginase, enzyme that produces urea and ornithine, last precursor of polyamine pathway. This pathway is used by the parasite to replicate and it is essential to establish the infection in the mammalian host. L-arginine is not synthesized by the parasite, so its uptake occurs through the amino acid permease 3 (AAP3).

Characterization of a Novel Endoplasmic Reticulum Protein Involved in Tubercidin Resistance in Leishmania major.

Background: Tubercidin (TUB) is a toxic adenosine analog with potential antiparasitic activity against Leishmania, with mechanism of action and resistance that are not completely understood. For understanding the mechanisms of action and identifying the potential metabolic pathways affected by this drug, we employed in this study an overexpression/selection approach using TUB for the identification of potential targets, as well as, drug resistance genes in L. major.