Herein, we performed microarray experiments in Schwann cells infected with live M. leprae and identified novel differentially expressed genes (DEG) in M. leprae infected cells. Also, we selected candidate genes associated or implicated with leprosy in genetic studies and biological experiments. Forty-seven genes were selected for validation in two independent types of samples by multiplex qPCR. First, an in vitro model using THP-1 cells was infected with live Mycobacterium leprae and M. bovis bacillus Calmette-Guérin (BCG). In a second situation, mRNA obtained from nerve biopsies from patients with leprosy or other peripheral neuropathies was tested. We detected DEGs that discriminate M. bovis BCG from M. leprae infection. Specific signatures of susceptible responses after M. leprae infection when compared to BCG lead to repression of genes, including CCL2, CCL3, IL8 and SOD2. The same 47-gene set was screened in nerve biopsies, which corroborated the down-regulation of CCL2 and CCL3 in leprosy, but also evidenced the down-regulation of genes involved in mitochondrial metabolism, and the up-regulation of genes involved in lipid metabolism and ubiquitination. Finally, a gene expression signature from DEG was identified in patients confirmed of having leprosy. A classification tree was able to ascertain 80% of the cases as leprosy or non-leprous peripheral neuropathy based on the expression of only LDLR and CCL4. A general immune and mitochondrial hypo-responsive state occurs in response to M. leprae infection. Also, the most important genes and pathways have been highlighted providing new tools for early diagnosis and treatment of leprosy.

Conflicting findings about the association between leprosy and TLR1 variants N248S and I602S have been reported. Here, we performed case-control and family based studies, followed by replication in 2 case-control populations from Brazil, involving 3162 individuals. Results indicated an association between TLR1 248S and leprosy in the case-control study (SS genotype odds ratio [OR], 1.81; P = .004) and the family based study (z = 2.02; P = .05). This association was consistently replicated in other populations (combined OR, 1.51; P < .001), corroborating the finding that 248S is a susceptibility factor for leprosy. Additionally, we demonstrated that peripheral blood mononuclear cells (PBMCs) carrying 248S produce a lower tumor necrosis factor/interleukin-10 ratio when stimulated with Mycobacterium leprae but not with lipopolysaccharide or PAM3cysK4. The same effect was observed after infection of PBMCs with the Moreau strain of bacillus Calmette-Guerin but not after infection with other strains. Finally, molecular dynamics simulations indicated that the Toll-like receptor 1 structure containing 248S amino acid is different from the structure containing 248N. Our results suggest that TLR1 248S is associated with an increased risk for leprosy, consistent with its hypoimmune regulatory function.

Mycobacterium leprae infects macrophages and Schwann cells inducing a gene expression program to facilitate its replication and progression to disease. MicroRNAs (miRNAs) are key regulators of gene expression and could be involved during the infection. To address the genetic influence of miRNAs in leprosy, we enrolled 1,098 individuals and conducted a case-control analysis in order to study four miRNAs genes containing single nucleotide polymorphism (miRSNP). We tested miRSNP-125a (rs12975333 G>T), miRSNP-223 (rs34952329 *>T), miRSNP-196a-2 (rs11614913 C>T) and miRSNP-146a (rs2910164 G>C). Amongst them, miRSNP-146a was the unique gene associated with risk to leprosy per se (GC OR = 1.44, p = 0.04; CC OR = 2.18, p = 0.0091). We replicated this finding showing that the C-allele was over-transmitted (p = 0.003) using a transmission-disequilibrium test. A functional analysis revealed that live M. leprae (MOI 100∶1) was able to induce miR-146a expression in THP-1 (p<0.05). Furthermore, pure neural leprosy biopsies expressed augmented levels of that miRNA as compared to biopsy samples from neuropathies not related with leprosy (p = 0.001). Interestingly, carriers of the risk variant (C-allele) produce higher levels of mature miR-146a in nerves (p = 0.04). From skin biopsies, although we observed augmented levels of miR-146a, we were not able to correlate it with a particular clinical form or neither host genotype. MiR-146a is known to modulate TNF levels, thus we assessed TNF expression (nerve biopsies) and released by peripheral blood mononuclear cells infected with BCG Moreau. In both cases lower TNF levels correlates with subjects carrying the risk C-allele, (p = 0.0453 and p = 0.0352; respectively), which is consistent with an immunomodulatory role of this miRNA in leprosy.

A survey of the Trypanosoma vivax genome was carried out by the genome sequence survey (GSS) approach resulting in 1,086 genomic sequences. A total of 455 high-quality GSS sequences were generated, consisting of 331 non-redundant sequences distributed in 264 singlets and 67 clusters in a total of 135.5 Kb of the T. vivax genome. The estimation of the overall G+C content, and the prediction of the presence of ORFs and putative genes were carried out using the Glimmer and Jemboss packages. Analysis of the obtained sequences was carried out by BLAST programs against 12 different databases and also using the Conserved Domain Database, InterProScan, and tRNAscan-SE. Along with the existing 23 T. vivax entries in the GenBank, the 32 putative genes predicted and the 331 non-redundant GSS sequences reported herein represent new potential markers for the development of PCRbased assays for specific diagnosis and typing of Trypanosoma vivax.

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