Leprosy susceptibility: genetic variations regulate innate and adaptive immunity, and disease outcome

Altered DNA methylation within DNMT3A, AHRR, LTA/TNF loci mediates the effect of smoking on inflammatory bowel disease

This work aims to investigate how smoking exerts effect on the development of inflammatory bowel disease (IBD). A prospective cohort study and a Mendelian randomization study are first conducted to evaluate the association between smoking behaviors, smoking-related DNA methylation and the risks of Crohn's disease (CD) and ulcerative colitis (UC). We then perform both genome-wide methylation analysis and co-localization analysis to validate the observed associations. Compared to never smoking, current and previous smoking habits are associated with increased CD (P = 7.09 × 10-10) and UC (P < 2 × 10-16) risk, respectively. DNA methylation alteration at cg17742416 [DNMT3A] is linked to both CD (P = 7.30 × 10-8) and UC (P = 1.04 × 10-4) risk, while cg03599224 [LTA/TNF] is associated with CD risk (P = 1.91 × 10-6), and cg14647125 [AHRR] and cg23916896 [AHRR] are linked to UC risk (P = 0.001 and 0.002, respectively). Our study identifies biological mechanisms and pathways involved in the effects of smoking on the pathogenesis of IBD.

Immunohistochemical Characterization of M1, M2, and M4 Macrophages in Leprosy Skin Lesions

Mycobacterium leprae is the etiological agent of leprosy. Macrophages (Mφs) are key players involved in the pathogenesis of leprosy. In this study, immunohistochemical analysis was performed to examine the phenotype of Mφ subpopulations, namely M1, M2, and M4, in the skin lesions of patients diagnosed with leprosy. Based on the database of treatment-naïve patients treated between 2015 and 2019 at the Department of Dermatology of the University of the State of Pará, Belém, routine clinical screening samples were identified. The monolabeling protocol was used for M1 macrophages (iNOS, IL-6, TNF-α) and M2 macrophages (IL-10, IL-13, CD163, Arginase 1, TGF-β, FGFb), and the double-labeling protocol was used for M4 macrophages (IL-6, MMP7, MRP8, TNF-α e CD68). To confirm the M4 macrophage lineage, double labeling of the monoclonal antibodies CD68 and MRP8 was also performed. Our results demonstrated a statistically significant difference for the M1 phenotype among the Virchowian (VV) (4.5 ± 1.3, p < 0.0001), Borderline (1.6 ± 0.4, p < 0.0001), and tuberculoid (TT) (12.5 ± 1.8, p < 0.0001) clinical forms of leprosy. Additionally, the M2 phenotype showed a statistically significant difference among the VV (12.5 ± 2.3, p < 0.0001), Borderline (1.3 ± 0.2, p < 0.0001), and TT (3.2 ± 0.7, p < 0.0001) forms. For the M4 phenotype, a statistically significant difference was observed in the VV (9.8 ± 1.7, p < 0.0001), Borderline (1.2 ± 0.2, p < 0.0001), and TT (2.6 ± 0.7, p < 0.0001) forms. A significant correlation was observed between the VV M1 and M4 (r = 0.8712; p = 0.0000) and between the VV M2 × TT M1 (r = 0.834; p = 0.0002) phenotypes. The M1 Mφs constituted the predominant Mφ subpopulation in the TT and Borderline forms of leprosy, whereas the M2 Mφs showed increased immunoexpression and M4 was the predominant Mφ phenotype in VV leprosy. These results confirm the relationship of the Mφ profile with chronic pathological processes of the inflammatory response in leprosy.

Low levels of TNFA gene expression seem to favor the development of pulmonary tuberculosis in a population from the Brazilian Amazon

TNF-α is a Th1 cytokine profile active in the control of Mycobacterium tuberculosis infection, IL-10 is associated with persistence of bacterial infection. The aim of the study was to investigate the association of TNFA -308G/A and IL10 -819C/T polymorphisms and TNFA and IL10 gene expression levels with pulmonary and extrapulmonary tuberculosis (n = 200) and control (n = 200). The individuals were submitted to genotyping and quantification of gene expression performed by real-time quantitative polymerase chain reaction (qPCR). No association was observed between the frequencies of polymorphisms evaluated and pulmonary tuberculosis. The frequency of polymorphic genotypes for TNFA -308G/A were associated with the extrapulmonary tuberculosis (p = 0.0445). The levels of TNFA expression were lower in the pulmonary tuberculosis group than in the control (p = 0.0009). There was a positive correlation between the levels of TNFA and IL10 in patients with pulmonary tuberculosis (r = 0.560; p = 0.0103). Reduced levels of TNFA expression may promote the formation of an anti-inflammatory microenvironment, favoring the persistence of the bacillus in the host, contributing to the establishment of pulmonary tuberculosis.

Disease mechanisms as subtypes: Microbiome

Abnormalities in gut microbiota have been suggested to be involved in the pathophysiology and progression of Parkinson's disease (PD). Gastrointestinal nonmotor symptoms often precede the onset of motor features in PD, suggesting a role for gut dysbiosis in neuroinflammation and α-synuclein (α-syn) aggregation. In the first part of this chapter, we analyze critical features of healthy gut microbiota and factors (environmental and genetic) that modify its composition. In the second part, we focus on the mechanisms underlying the gut dysbiosis and how it alters anatomically and functionally the mucosal barrier, triggering neuroinflammation and subsequently α-syn aggregation. In the third part, we describe the most common alterations in the gut microbiota of PD patients, dividing the gastrointestinal system in higher and lower tract to examine the association between microbiota abnormalities and clinical features. In the final section, we report on current and future therapeutic approaches to gut dysbiosis aiming to either reduce the risk for PD, modify the disease course, or improve the pharmacokinetic profile of dopaminergic therapies. We also suggest that further studies will be needed to clarify the role of the microbiome in PD subtyping and of pharmacological and nonpharmacological interventions in modifying specific microbiota profiles in individualizing disease-modifying treatments in PD.

Association of the rs2111234, rs3135499, rs8057341 polymorphisms in the NOD2 gene with leprosy: A case-control study in the Norte de Santander, Colombia population

BACKGROUND

Leprosy is a chronic infectious disease caused by Mycobacterium leprae. The development of leprosy involves several factors, including the causative agent, the individual host's immune response, environmental factors, and the genetic background of the host. Specifically, the host's innate immune response, encoded by genes, determines their susceptibility to developing leprosy post-infection. Polymorphic variants in the nucleotide-binding oligomerization domain 2 (NOD2) gene are associated with leprosy among populations in a variety of endemic areas around the world. Colombia, a country located in the tropical zone, has several leprosy-endemic regions, including Norte de Santander. The aim of this study was to analyze the rs7194886, rs2111234, rs3135499, and rs8057341 single nucleotide polymorphisms (SNPs) in the NOD2 gene using a case-control study to determine whether they confer greater or lesser susceptibility to the development of leprosy.

METHODOLOGY

The TaqMan qPCR amplification system was used for SNPs detection.

FINDINGS

An association between the A-rs8057341 SNP (p = 0,006286) and resistance to leprosy was found. However, the rs3135499 (p = 0,9063) and rs2111234 (p = 0.1492) were not found to be associated with leprosy susceptibility. In addition, the rs7194886 SNP was not found to be in Hardy-Weinberg equilibrium (HWE) in the study population. The GAG haplotype, consisting of SNPs rs2111234-G, rs3135499-A, and rs8057341G, acts as a susceptibility factor for the development of leprosy in women. SNPs rs3135499 and rs8057341 are functionally related to decreased NOD2 expression according to an in-silico analysis.

CONCLUSIONS

The SNPs rs8057341-A was related with resistance to leprosy and the haplotype rs2111234-G, rs3135499-A and rs8057341-G SNPs was related with susceptibility in the Norte de Santander Colombia, studied population.

Offense and Defense in Granulomatous Inflammation Disease

Granulomatous inflammation (GI) diseases are a group of chronic inflammation disorders characterized by focal collections of multinucleated giant cells, epithelioid cells and macrophages, with or without necrosis. GI diseases are closely related to microbes, especially virulent intracellular bacterial infections are important factors in the progression of these diseases. They employ a range of strategies to survive the stresses imposed upon them and persist in host cells, becoming the initiator of the fighting. Microbe-host communication is essential to maintain functions of a healthy host, so defense capacity of hosts is another influence factor, which is thought to combine to determine the result of the fighting. With the development of gene research technology, many human genetic loci were identified to be involved in GI diseases susceptibility, providing more insights into and knowledge about GI diseases. The current review aims to provide an update on the most recent progress in the identification and characterization of bacteria in GI diseases in a variety of organ systems and clinical conditions, and examine the invasion and escape mechanisms of pathogens that have been demonstrated in previous studies, we also review the existing data on the predictive factors of the host, mainly on genetic findings. These strategies may improve our understanding of the mechanisms underlying GI diseases, and open new avenues for the study of the associated conditions in the future.

Association of CD209 (DC-SIGN) rs735240 SNV with paucibacillary leprosy in the Brazilian population and its functional effects

BACKGROUND

Leprosy, caused by Mycobacterium leprae, is a public health problem in Brazil that affects peripheral nerves, resulting in physical disabilities. During host-pathogen interactions, the immune response determines leprosy outcomes from a localised (paucibacillary) form to a disseminated (multibacillary) form. The recognition of M. leprae involves the DC-SIGN receptor, which is present on the dendritic cells (DCs) and participates in immune activation.

OBJECTIVES

To evaluate the association of polymorphisms in the promoter region of the gene encoding DC-SIGN (CD209) and the clinical form of leprosy, and to investigate its functional effects.

METHODS

The study population included 406 leprosy patients from an endemic area in Brazil [310 multibacillary (MB); 96 paucibacillary (PB)]. A functional evaluation based on the effects of the single nucleotide variant (SNV) associated with PB leprosy on the specific immune response was also performed.

RESULTS

The GA genotype and the presence of the A allele of rs735240 (-939G>A) were associated with PB leprosy [OR: 2.09 (1.18-3.69) and 1.84 (1.07-3.14), respectively]. Carriers of the A allele showed reduced expression of CD209 and TGF-β1 in leprosy lesions in comparison with individuals with GG genotype, in addition to a higher response to the Mitsuda test.

CONCLUSION

These data suggest that rs735240 influences the immune response against M. leprae and clinical presentation of leprosy.

Serum IL-6 level and nutrition status as potential predictors of clinical leprosy development among household contacts in the endemic areas

Background

Leprosy is a chronic infectious disease that can lead to severe life-long disabilities. Close contacts of leprosy patients have a higher risk of acquiring the disease. Nevertheless, there is a lack of reliable markers to predict Mycobacterium leprae infection. We aim to identify new potential markers for developing clinical leprosy among contacts.

Methods

Serum levels of IL-6, IL-8, IL-10, hemoglobin, ferritin and transferrin saturation were measured in 67 multibacillary leprosy (MB) patients, 65 household contacts (HC) of MB patients, and 127 endemic controls (EC). By means of multivariate logistic regression and ROC analyses, we analyze baseline variables and laboratory parameters that showed significant differences between MB with HC and EC groups and obtained the respective areas under the curve (AUC). Optimal cut-off value of the associated cytokines was also determined.

Results

Elevated IL-6 level was observed in MB compared to HC and EC (p=0.022 and 0.0041, respectively). Anemia and iron deficiency were also higher in MB group compared to HC or EC (p&lt;0.001). Likewise, we observed an increased risk of having MB leprosy in underweight HC [OR 2.599 (0.991; 6.820)] and underweight EC [2.176 (1.010; 4.692)]. Further analysis with ROC showed that high serum IL-6 level, underweight, anemia, and iron deficiency can discriminate leprosy from their household contacts [AUC 0.843 (95% CI 0.771-0.914); p=0.000; optimal cut-off value of IL-6 = 9.14 pg/ml].

Conclusions

Our results suggest that serum IL-6 and nutrition status could serve as potential prognostic markers for the development of clinical leprosy in infected individuals.

GPR174 mRNA Acts as a Novel Prognostic Biomarker for Patients With Sepsis via Regulating the Inflammatory Response

Previous studies indicated that G-protein coupled receptor 174 (GPR174) is involved in the dysregulated immune response of sepsis, however, the clinical value and effects of GPR174 in septic patients are still unknown. This study is aimed to evaluate the potential value of GPR174 as a prognostic biomarker for sepsis and explore the pathological function of GPR174 in cecal ligation and puncture (CLP)-induced septic mice. In this prospective longitudinal study, the expressions of peripheral GPR174 mRNA were measured in 101 septic patients, 104 non-septic ICU controls, and 46 healthy volunteers at Day 1, 7 after ICU (Intensive Care Unit) admission, respectively. Then, the clinical values of GPR174 for the diagnosis, severity assessment, and prognosis of sepsis were analyzed. Moreover, the expressions of GPR174 mRNA in CLP-induced septic mice were detected, and Gpr174-knockout (KO) mice were used to explore its effects on inflammation. The results showed that the levels of GPR174 mRNA were significantly decreased in septic patients compared with non-septic ICU and healthy controls. In addition, the expressions of GPR174 mRNA were correlated with the lymphocyte (Lym) counts, C-reactive protein (CRP), and APACHE II and SOFA scores. The levels of GPR174 mRNA at Day 7 had a high AUC in predicting the death of sepsis (0.83). Further, we divided the septic patients into the higher and lower GPR174 mRNA expression groups by the ROC cut-off point, and the lower group was significantly associated with poor survival rate (P = 0.00139). Similarly, the expressions of peripheral Gpr174 mRNA in CLP-induced septic mice were also significantly decreased, and recovered after 72 h. Intriguingly, Gpr174-deficient could successfully improve the outcome with less multi-organ damage, which was mainly due to an increased level of IL-10, and decreased levels of IL-1β and TNF-α. Further, RNA-seq showed that Gpr174 deficiency significantly induced a phenotypic shift toward multiple immune response pathways in septic mice. In summary, our results indicated that the expressions of GPR174 mRNA were associated with the severity of sepsis, suggesting that GPR174 could be a potential prognosis biomarker for sepsis. In addition, GPR174 plays an important role in the development of sepsis by regulating the inflammatory response.

The Paratuberculosis Paradigm Examined: A Review of Host Genetic Resistance and Innate Immune Fitness in Mycobacterium avium subsp. Paratuberculosis Infection

Paratuberculosis, or Johne's Disease (JD) is a debilitating chronic enteritis mainly affecting ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP). This organism causes worldwide economic losses to the livestock industry, and is of public health importance due to the potential zoonotic risk between MAP and Crohn's disease (CD) in humans. Without economical treatments, or a vaccine capable of preventing infection without causing cross-reactions with bovine tuberculosis, test-and-cull methods for disease control are imperative. Unfortunately, difficulties in diagnostics and long subclinical stage hinder adequate control and is further complicated by variation in MAP exposure outcome. Interestingly, the majority of infections result in asymptomatic presentation and never progress to clinical disease. One contributing factor is host genetics, where polymorphisms in innate immune genes have been found to influence resistance and susceptibility to disease. Candidate genes identified across studies overlap with those found in CD and tuberculosis including; Solute carrier family 11 member 1 gene (SLC11A1), Nucleotide-binding-oligomerization domain containing gene 2 (NOD2), Major histocompatibility complex type II (MHC-II), and Toll-like receptor (TLR) genes. This review will highlight evidence supporting the vital role of these genes in MAP infection outcome, associated challenges, and implications for the future of JD research.

Putative pathogen-selected polymorphisms in the PKLR gene are associated with mycobacterial susceptibility in Brazilian and African populations

Pyruvate kinase (PK), encoded by the PKLR gene, is a key player in glycolysis controlling the integrity of erythrocytes. Due to Plasmodium selection, mutations for PK deficiency, which leads to hemolytic anemia, are associated with resistance to malaria in sub-Saharan Africa and with susceptibility to intracellular pathogens in experimental models. In this case-control study, we enrolled 4,555 individuals and investigated whether PKLR single nucleotide polymorphisms (SNPs) putatively selected for malaria resistance are associated with susceptibility to leprosy across Brazil (Manaus-North; Salvador-Northeast; Rondonópolis-Midwest and Rio de Janeiro-Southeast) and with tuberculosis in Mozambique. Haplotype T/G/G (rs1052176/rs4971072/rs11264359) was associated with leprosy susceptibility in Rio de Janeiro (OR = 2.46, p = 0.00001) and Salvador (OR = 1.57, p = 0.04), and with tuberculosis in Mozambique (OR = 1.52, p = 0.07). This haplotype downregulates PKLR expression in nerve and skin, accordingly to GTEx, and might subtly modulate ferritin and haptoglobin levels in serum. Furthermore, we observed genetic signatures of positive selection in the HCN3 gene (xpEHH>2 -recent selection) in Europe but not in Africa, involving 6 SNPs which are PKLR/HCN3 eQTLs. However, this evidence was not corroborated by the other tests (FST, Tajima's D and iHS). Altogether, we provide evidence that a common PKLR locus in Africans contribute to mycobacterial susceptibility in African descent populations and also highlight, for first, PKLR as a susceptibility gene for leprosy and TB.

Clinical characterization and therapeutic targets of vitamin A in patients with hepatocholangiocarcinoma and coronavirus disease

Recent reports indicate that patients with hepatocholangiocarcinoma (CHOL) have a higher morbidity and mortality rate for coronavirus disease (COVID-19). Anti-CHOL/COVID-19 medicines are inexistent. Vitamin A (VA) refers to a potent nutrient with anti-cytotoxic and anti-inflammatory actions. Therefore, this study aimed to determine the potential functions and molecular mechanisms of VA as a potential treatment for patients with both CHOL and COVID-19 (CHOL/COVID-19). The transcriptome data of CHOL patients were obtained from the Cancer Genome Analysis database. Furthermore, the network pharmacology approach and bioinformatics analysis were used to identify and reveal the molecular functions, therapeutic biotargets, and signaling of VA against CHOL/COVID-19. First, clinical findings identified the medical characteristics of CHOL patients with COVID-19, such as susceptibility gene, prognosis, recurrence, and survival rate. Anti-viral and anti-inflammatory pathways, and immunopotentiation were found as potential targets of VA against CHOL/COVID-19. These findings illustrated that VA may contribute to the clinical management of CHOL/COVID-19 achieved by induction of cell repair, suppression of oxidative stress and inflammatory reaction, and amelioration of immunity. Nine vital therapeutic targets (BRD2, NOS2, GPT, MAPK1, CXCR3, ICAM1, CDK4, CAT, and TMPRSS13) of VA against CHOL/COVID-19 were identified. For the first time, the potential pharmacological biotargets, function, and mechanism of action of VA in CHOL/COVID-19 were elucidated.

Blood RNA signature RISK4LEP predicts leprosy years before clinical onset

BACKGROUND

Leprosy, a chronic infectious disease caused by Mycobacterium leprae, is often late- or misdiagnosed leading to irreversible disabilities. Blood transcriptomic biomarkers that prospectively predict those who progress to leprosy (progressors) would allow early diagnosis, better treatment outcomes and facilitate interventions aimed at stopping bacterial transmission. To identify potential risk signatures of leprosy, we collected whole blood of household contacts (HC, n=5,352) of leprosy patients, including individuals who were diagnosed with leprosy 4-61 months after sample collection.

METHODS

We investigated differential gene expression (DGE) by RNA-Seq between progressors before presence of symptoms (n=40) and HC (n=40), as well as longitudinal DGE within each progressor. A prospective leprosy signature was identified using a machine learning approach (Random Forest) and validated using reverse transcription quantitative PCR (RT-qPCR).

FINDINGS

Although no significant intra-individual longitudinal variation within leprosy progressors was identified, 1,613 genes were differentially expressed in progressors before diagnosis compared to HC. We identified a 13-gene prospective risk signature with an Area Under the Curve (AUC) of 95.2%. Validation of this RNA-Seq signature in an additional set of progressors (n=43) and HC (n=43) by RT-qPCR, resulted in a final 4-gene signature, designated RISK4LEP (MT-ND2, REX1BD, TPGS1, UBC) (AUC=86.4%).

INTERPRETATION

This study identifies for the first time a prospective transcriptional risk signature in blood predicting development of leprosy 4 to 61 months before clinical diagnosis. Assessment of this signature in contacts of leprosy patients can function as an adjunct diagnostic tool to target implementation of interventions to restrain leprosy development.

FUNDING

This study was supported by R2STOP Research grant, the Order of Malta-Grants-for-Leprosy-Research, the Q.M. Gastmann-Wichers Foundation and the Leprosy Research Initiative (LRI) together with the Turing Foundation (ILEP# 702.02.73 and # 703.15.07).

Large-Scale Gene Expression Signatures Reveal a Microbicidal Pattern of Activation in Mycobacterium leprae-Infected Monocyte-Derived Macrophages With Low Multiplicity of Infection

Leprosy is a disease with a clinical spectrum of presentations that is also manifested in diverse histological features. At one pole, lepromatous lesions (L-pole) have phagocytic foamy macrophages heavily parasitized with freely multiplying intracellular Mycobacterium leprae. At the other pole, the presence of epithelioid giant cells and granulomatous formation in tuberculoid lesions (T-pole) lead to the control of M. leprae replication and the containment of its spread. The mechanism that triggers this polarization is unknown, but macrophages are central in this process. Over the past few years, leprosy has been studied using large scale techniques to shed light on the basic pathways that, upon infection, rewire the host cellular metabolism and gene expression. M. leprae is particularly peculiar as it invades Schwann cells in the nerves, reprogramming their gene expression leading to a stem-like cell phenotype. This modulatory behavior exerted by M. leprae is also observed in skin macrophages. Here, we used live M. leprae to infect (10:1 multiplicity of infection) monocyte-derived macrophages (MDMs) for 48 h and analyzed the whole gene expression profile using microarrays. In this model, we observe an intense upregulation of genes consistent with a cellular immune response, with enriched pathways including peptide and protein secretion, leukocyte activation, inflammation, and cellular divalent inorganic cation homeostasis. Among the most differentially expressed genes (DEGs) are CCL5/RANTES and CYP27B1, and several members of the metallothionein and metalloproteinase families. This is consistent with a proinflammatory state that would resemble macrophage rewiring toward granulomatous formation observed at the T-pole. Furthermore, a comparison with a dataset retrieved from the Gene Expression Omnibus of M. leprae-infected Schwann cells (MOI 100:1) showed that the patterns among the DEGs are highly distinct, as the Schwann cells under these conditions had a scavenging and phagocytic gene profile similar to M2-like macrophages, with enriched pathways rearrangements in the cytoskeleton, lipid and cholesterol metabolism and upregulated genes including MVK, MSMO1, and LACC1/FAMIN. In summary, macrophages may have a central role in defining the paradigmatic cellular (T-pole) vs. humoral (L-pole) responses and it is likely that the multiplicity of infection and genetic polymorphisms in key genes are gearing this polarization.

Mitochondria: Powering the Innate Immune Response to Mycobacterium tuberculosis Infection

Within the last decade, we have learned that damaged mitochondria activate many of the same innate immune pathways that evolved to sense and respond to intracellular pathogens. These shared responses include cytosolic nucleic acid sensing and type I interferon (IFN) expression, inflammasome activation that leads to pyroptosis, and selective autophagy (called mitophagy when mitochondria are the cargo). Because mitochondria were once bacteria, parallels between how cells respond to mitochondrial and bacterial ligands are not altogether surprising. However, the potential for cross talk or synergy between bacterium- and mitochondrion-driven innate immune responses during infection remains poorly understood. This interplay is particularly striking, and intriguing, in the context of infection with the intracellular bacterial pathogen Mycobacterium tuberculosis (Mtb). Multiple studies point to a role for Mtb infection and/or specific Mtb virulence factors in disrupting the mitochondrial network in macrophages, leading to metabolic changes and triggering potent innate immune responses. Research from our laboratories and others argues that mutations in mitochondrial genes can exacerbate mycobacterial disease severity by hyperactivating innate responses or activating them at the wrong time. Indeed, growing evidence supports a model whereby different mitochondrial defects or mutations alter Mtb infection outcomes in distinct ways. By synthesizing the current literature in this minireview, we hope to gain insight into the molecular mechanisms driving, and consequences of, mitochondrion-dependent immune polarization so that we might better predict tuberculosis patient outcomes and develop host-directed therapeutics designed to correct these imbalances.

Increased oxidative stress in elderly leprosy patients is related to age but not to bacillary load

BACKGROUND

Leprosy continues to be a public health problem in Brazil. Furthermore, detection rates in elderly people have increased, particularly those of multibacillary (L-Lep) patients, who are responsible for transmitting M. leprae. Part of the decline in physiological function during aging is due to increased oxidative damage and change in T cell subpopulations, which are critical in defense against the disease. It is not still clear how age-related changes like those related to oxidation affect elderly people with leprosy. The aim of this work was to verify whether the elderly leprosy patients have higher ROS production and how it can impact the evolution of leprosy.

METHODOLOGY/PRINCIPAL FINDINGS

87 leprosy patients, grouped according to age range and clinical form of leprosy, and 25 healthy volunteers were analyzed. Gene expression analysis of antioxidant and oxidative burst enzymes were performed in whole blood using Biomark's microfluidic-based qPCR. The same genes were evaluated in skin lesion samples by RT-qPCR. The presence of oxidative damage markers (carbonylated proteins and 4-hydroxynonenal) was analyzed by a DNPH colorimetric assay and immunofluorescence. Carbonylated protein content was significantly higher in elderly compared to young patients. One year after multidrug therapy (MDT) discharge and M. leprae clearance, oxidative damage increased in young L-Lep patients but not in elderly ones. Both elderly T and L-Lep patients present higher 4-HNE in cutaneous lesions than the young, mainly surrounding memory CD8+ T cells. Furthermore, young L-Lep demonstrated greater ability to neutralize ROS compared to elderly L-Lep patients, who presented lower gene expression of antioxidant enzymes, mainly glutathione peroxidase.

CONCLUSIONS/SIGNIFICANCE

We conclude that elderly patients present exacerbated oxidative damage both in blood and in skin lesions and that age-related changes can be an important factor in leprosy immunopathogenesis. Ultimately, elderly patients could benefit from co-supplementation of antioxidants concomitant to MDT, to avoid worsening of the disease.

HLA-DPB1 and HLA-C alleles are associated with leprosy in a Brazilian population

Despite intense efforts, the number of new cases of leprosy has remained significantly high over the past 20 years. Host genetic background is strongly linked to the pathogenesis of this disease, which is caused by Mycobacterium leprae (M. leprae), and there is a consensus that the most significant genetic association with leprosy is attributed to the major histocompatibility complex (MHC). Here, we investigated the association of human leukocyte antigen (HLA) class I and II genes with leprosy in a Brazilian population encompassing 826 individuals from a hyperendemic area of Brazil; HLA typing of class I (-A, -B, -C) and class II (-DRB1, -DQA1, -DQB1, -DPA1, and -DPB1) loci was conducted. Initially, the associations were tested using the chi-square test, with p-values adjusted using the false discovery rate (FDR) method. Next, statistically significant signals of the associations were submitted to logistic regression analyses to adjust for sex and molecular ancestry data. The results showed that HLA-C*08, -DPB1*04, and -DPB1*18 were associated with protective effects, while HLA-C*12 and -DPB1*105 were associated with susceptibility to leprosy. Thus, our findings reveal new associations between leprosy and the HLA-DPB1 locus and confirm previous associations between the HLA-C locus and leprosy.

Association of IL-10 Gene Polymorphism With IL-10 Secretion by CD4 and T Regulatory Cells in Human Leprosy

Leprosy is a chronic bacterial disease caused by Mycobacterium leprae. Cytokines are known to play vital role as a peacekeeper during inflammatory and other immunocompromised conditions such as leprosy. This study has tried to bridge the gap of information on cytokine gene polymorphisms and its potential role in the pathogenesis of leprosy. Interleukin-10 (IL-10) is an immunosuppressive cytokine, found to be elevated in leprosy that accounted for the suppression of host’s immune system by regulating the functions of other immune cells. T helper cells and T regulatory (Tregs) cells are the major source of IL-10 in lepromatous leprosy patients. In this study, we have documented the association of IL-10 cytokine gene polymorphism with the disease progression. A total of 132 lepromatous leprosy patients and 120 healthy controls were analyzed for IL-10 cytokine gene polymorphisms using PCR-SSP assay and flow cytometry was used to analyze IL-10 secretion by CD4 and Tregs in various genotype of leprosy patients. The frequencies of IL-10 (-819) TT and IL-10 (-1082) GG genotypes were significantly higher in leprosy patients as compared to healthy controls. This observation advocates that these genotypes were associated with the susceptibility and development of the disease. In addition, flow cytometry analysis demonstrated an increased number of IL-10 producing CD4 and Treg cells in IL-10 (819) TT genotype compared to CT and CC genotypes. These observations were further supported by immunohistochemical studies. Therefore, we can conclude that IL-10 cytokine gene polymorphisms by affecting its production can determine the predilection and progression of leprosy in the study population.

Association of NOD2 and IFNG single nucleotide polymorphisms with leprosy in the Amazon ethnic admixed population

Leprosy is a chronic infectious disease, caused by Mycobacterium leprae, which affects skin and peripheral nerves. Polymorphisms in genes associated with autophagy, metabolism, innate and adaptive immunity confer susceptibility to leprosy. However, these associations need to be confirmed through independent replication studies in different ethnicities. The population from Amazon state (northern Brazil) is admixed and it contains the highest proportion of Native American genetic ancestry in Brazil. We conducted a case-control study for leprosy in which we tested fourteen previously associated SNPs in key immune response regulating genes: TLR1 (rs4833095), NOD2 (rs751271, rs8057341), TNF (rs1800629), IL10 (rs1800871), CCDC122/LACC1 (rs4942254), PACRG/PRKN (rs9356058, rs1040079), IFNG (rs2430561), IL6 (rs2069845), LRRK2 (rs7298930, rs3761863), IL23R (rs76418789) and TYK2 (rs55882956). Genotyping was carried out by allelic discrimination in 967 controls and 412 leprosy patients. Association with susceptibility was assessed by logistic regression analyses adjusted for the following covariates: gender, age and ancestry. Genetic ancestry was similar in case and control groups. Statistically significant results were only found for IFNG and NOD2. The rs8057341 polymorphism within NOD2 was identified as significant for the AA genotype (OR = 0.56; 95% CI, 0.37-0.84; P = 0.005) and borderline for the A allele (OR = 0.76; 95% CI, 0.58-1.00; P = 0.053) and carrier (OR = 0.76; 95% CI, 0.58-1.00; P = 0.051). The rs2430561 SNP in IFNG was associated with disease susceptibility for the AT genotype (OR = 1.40; 95% CI, 1.06-1.85; P = 0.018) and carrier (OR = 1.44; 95% CI, 1.10-1.88; P = 0.008). We confirmed that NOD2 and IFNG are major players in immunity against M.leprae in the Amazon ethnic admixed population.

The gut microbiome in Parkinson's disease: A culprit or a bystander?

In recent years, large-scale metagenomics projects such as the Human Microbiome Project placed the gut microbiota under the spotlight of research on its role in health and in the pathogenesis several diseases, as it can be a target for novel therapeutical approaches. The emerging concept of a microbiota modulation of the gut-brain axis in the pathogenesis of neurodegenerative disorders has been explored in several studies in animal models, as well as in human subjects. Particularly, research on changes in the composition of gut microbiota as a potential trigger for alpha-synuclein (α-syn) pathology in Parkinson's disease (PD) has gained increasing interest. In the present review, we first provide the basis to the understanding of the role of gut microbiota in healthy subjects and the molecular basis of the gut-brain interaction, focusing on metabolic and neuroinflammatory factors that could trigger the alpha-synuclein conformational changes and aggregation. Then, we critically explored preclinical and clinical studies reporting on the changes in gut microbiota in PD, as compared to healthy subjects. Furthermore, we examined the relationship between the gut microbiota and PD clinical features, discussing data consistently reported across studies, as well as the potential sources of inconsistencies. As a further step toward understanding the effects of gut microbiota on PD, we discussed the relationship between dysbiosis and response to dopamine replacement therapy, focusing on Levodopa metabolism. We conclude that further studies are needed to determine whether the gut microbiota changes observed so far in PD patients is the cause or, instead, it is merely a consequence of lifestyle changes associated with the disease. Regardless, studies so far strongly suggest that changes in microbiota appears to be impactful in pathogenesis of neuroinflammation. Thus, dysbiotic microbiota in PD could influence the disease course and response to medication, especially Levodopa. Future research will assess the impact of microbiota-directed therapeutic intervention in PD patients.

Genetic Variation on TNF/LTA and TNFRSF1A Genes is Associated with Outcomes of Hepatitis C Virus Infection

Hepatitis C virus (HCV) infections are a serious global-scaled public health problem. Tumor necrosis factor (TNF)/lymphotoxin alpha (LTA) has been found to play a crucial role in relation to the outcomes of HCV infection after it binds to TNF receptor superfamily member 1A (TNFRSF1A). Thus, we investigated whether or not the TNF/LTA gene cluster and TNFRSF1A gene polymorphisms were associated with the outcomes of HCV infection. 1103 control participants without HCV infection, 497 patients with spontaneous clearance of HCV infection, and 713 patients with persistent HCV infection were enrolled. Rs2229094, rs1041981, rs1799964, and rs767455 were genotyped using the ABI TaqMan allelic discrimination assay. After adjusting for age, gender, and after determining a high-risk population, we used logistic regression analyses for which results indicated that the rs767455-C allele was associated with a reduced risk of HCV infection compared to respective results for the wild-type T allele (dominant model: adjusted OR = 0.74, 95% CI = 0.60-0.92, P = .006; additive model: adjusted OR = 0.76, 95% CI = 0.62-0.91, P = .004). Results also indicated that the rs1041981-A allele was associated with a decreased risk of persistent HCV infection compared to respective results for the wild-type C allele (additive model: adjusted OR = 0.81, 95% CI = 0.68-0.96, P = .017). Genetic polymorphisms in the LTA and TNFRSF1A genes were found to have been potentially important in relation to the susceptibility and chronicity of HCV infection among Chinese Han population.

Involvement of TNF-Producing CD8+ Effector Memory T Cells with Immunopathogenesis of Erythema Nodosum Leprosum in Leprosy Patients

Type 2 reaction (T2R) or erythema nodosum leprosum (ENL), a sudden episode of acute inflammation predominantly affecting lepromatous leprosy patients (LL), characterized by a reduced cellular immune response. This possibly indicates a close relationship between the onset of T2R and the altered frequency, and functional activity of T lymphocytes, particularly of memory subsets. This study performed ex vivo and in vitro characterizations of T cell blood subpopulations from LL patients with or without T2R. In addition, the evaluation of activity of these subpopulations was performed by analyzing the frequency of these cells producing IFN-γ, TNF, and IL-10 by flow cytometry. Furthermore, the expression of transcription factors, for the differentiation of T cells, were analyzed by quantitative real-time polymerase chain reaction. Our results showed an increased frequency of CD8⁺/TNF⁺ effector memory T cells (T_EM) among T2Rs. Moreover, there was evidence of a reduced frequency of CD4 and CD8⁺ IFN-γ-producing cells in T2R, and a reduced expression of STAT4 and TBX21. Finally, a significant and positive correlation between bacteriological index (BI) of T2R patients and CD4⁺/TNF⁺ and CD4⁺/IFN-γ⁺ T cells was observed. Thus, negative correlation between BI and the frequency of CD4⁺/IL-10⁺ T cells was noted. These results suggest that CD8⁺/TNF⁺ T_EM are primarily responsible for the transient alteration in the immune response to Mycobacterium leprae in ENL patients. Thus, our study improves our understanding of pathogenic mechanisms and might suggest new therapeutic approaches for leprosy.

Organization of the Skin Immune System and Compartmentalized Immune Responses in Infectious Diseases

The skin is an organ harboring several types of immune cells that participate in innate and adaptive immune responses. The immune system of the skin comprises both skin cells and professional immune cells that together constitute what is designated skin-associated lymphoid tissue (SALT). In this review, I extensively discuss the organization of SALT and the mechanisms involved in its responses to infectious diseases of the skin and mucosa. The nature of these SALT responses, and the cellular mediators involved, often determines the clinical course of such infections. I list and describe the components of innate immunity, such as the roles of the keratinocyte barrier and of inflammatory and natural killer cells. I also examine the mechanisms involved in adaptive immune responses, with emphasis on new cytokine profiles, and the role of cell death phenomena in host-pathogen interactions and control of the immune responses to infectious agents. Finally, I highlight the importance of studying SALT in order to better understand host-pathogen relationships involving the skin and detail future directions in the immunological investigation of this organ, especially in light of recent findings regarding the skin immune system.

Leprosy: A great imitator

In recent years, advances in medical diagnosis and treatment have greatly attracted our attention, whereas some rare diseases, such as leprosy, have not found a place in the medical education curriculum; their existence may even be forgotten. Although the prevalence and incidence rates for leprosy have been significantly reduced as a result of the control strategies of the World Health Organization, new cases still appear. A total of 214,783 new cases were reported from 143 countries during 2016, corresponding to the global new-case detection rate of 2.9 per 100,000 population. Leprosy proves to be a very interesting model due to its immunologic properties. It joins with syphilis, mycosis fungoides, cutaneous tuberculosis, and sarcoidosis as one of the great imitators. The diagnosis of leprosy can be simple and practical, but considering the diagnosis of leprosy in the differential diagnosis is the first requisite again.

The inflammasome in leprosy skin lesions: an immunohistochemical evaluation

Objective

Leprosy is a chronic infectious disease presenting with a spectrum of clinical manifestations that correspond to the type of immune response that develops in the host. Factors that may be involved in this process include inflammasomes, cytosolic proteins responsible for the activation of caspase 1, IL-1β and IL-18 secretion, and induction of a type of death called pyroptosis.

Patients and methods

We evaluated the expression of inflammasome markers (nucleotide-binding oligomerization domain-like receptor containing pyrin domain 1 [NLRP1], nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 [NLRP3], caspase 1, IL-1β, and IL-18) by immunohistochemistry in 43 samples of skin lesions of leprosy patients from the groups indeterminate (I) leprosy (13 patients), tuberculoid (TT) leprosy (15 patients), and lepromatous leprosy (LL; 15 patients).

Results

The evaluated markers were most upregulated in LL lesions, followed by lesions of TT leprosy and I leprosy. Differences were statistically significant between the I leprosy and LL leprosy forms and between the I leprosy and TT leprosy forms. Positive and significant correlations were found between IL-18 and caspase 1 in LL (r=0.7516, P=0.0012) and TT leprosy (r=0.7366, P=0.0017). In I leprosy, correlations were detected between caspase 1 and IL-1β (r=0.6412, P=0.0182), NLRP1 and IL-18 (r=0.5585, P=0.473), NLRP3 and IL-18 (r=0.6873, P=0.0094), and NLRP1 and NLRP3 (r=0.8040, P=0.0009).

Conclusion

The expression of inflammasome markers in LL lesions indicates the ineffectiveness of this protein complex in controlling the infection. Caspase 1 may be involved in the pyroptotic cell death in the lepromatous form of the disease. Inflammasomes may act together in the initial phase of I leprosy; this phenomenon may influence the clinical outcome of the disease.

Human genetics of mycobacterial disease

Mycobacterial diseases are caused by members of the genus Mycobacterium, acid-fast bacteria characterized by the presence of mycolic acids within their cell walls. Claiming almost 2 million lives every year, tuberculosis (TB) is the most common mycobacterial disease and is caused by infection with M. tuberculosis and, in rare cases, by M. bovis or M. africanum. The second and third most common mycobacterial diseases are leprosy and buruli ulcer (BU), respectively. Both diseases affect the skin and can lead to permanent sequelae and deformities. Leprosy is caused by the uncultivable M. leprae while the etiological agent of BU is the environmental bacterium M. ulcerans. After exposure to these mycobacterial species, a majority of individuals will not progress to clinical disease and, among those who do, inter-individual variability in disease manifestation and outcome can be observed. Susceptibility to mycobacterial diseases carries a human genetic component and intense efforts have been applied over the past decades to decipher the exact nature of the genetic factors controlling disease susceptibility. While for BU this search was mostly conducted on the basis of candidate genes association studies, genome-wide approaches have been widely applied for TB and leprosy. In this review, we summarize some of the findings achieved by genome-wide linkage, association and transcriptome analyses in TB disease and leprosy and the recent genetic findings for BU susceptibility.

Genetic Susceptibility to Leprosy-From Classic Immune-Related Candidate Genes to Hypothesis-Free, Whole Genome Approaches

Genetics plays a crucial role in controlling susceptibility to infectious diseases by modulating the interplay between humans and pathogens. This is particularly evident in leprosy, since the etiological agent, Mycobacterium leprae, displays semiclonal characteristics not compatible with the wide spectrum of disease phenotypes. Over the past decades, genetic studies have unraveled several gene variants as risk factors for leprosy per se, disease clinical forms and the occurrence of leprosy reactions. As expected, several of these genes are immune-related; yet, hypothesis-free approaches have led to genes not classically linked to immune response. The PARK2, originally described as a Parkinson's disease gene, illustrates the case: Parkin-the protein coded by PARK2-was defined as an important player regulating innate and adaptive immune responses only years after its description as a leprosy susceptibility gene. Interestingly, even with the use of powerful hypothesis-free study designs such as genome-wide association studies, most of the major gene effect controlling leprosy susceptibility remains elusive. One hypothesis to explain this "hidden heritability" is that rare variants not captured by classic association studies are of critical importance. To address this question, massively parallel sequencing of large segments of the human genome-even whole exomes/genomes-is an alternative to properly identify rare, disease-causing mutations. These mutations may then be investigated through sophisticated approaches such as cell reprogramming and genome editing applied to create in vitro models for functional leprosy studies.

Correlates of immune exacerbations in leprosy

Leprosy is still a considerable health threat in pockets of several low and middle income countries worldwide where intense transmission is witnessed, and often results in irreversible disabilities and deformities due to delayed- or misdiagnosis. Early detection of leprosy represents a substantial hurdle in present-day leprosy health care. The dearth of timely diagnosis has, however, particularly severe consequences in the case of inflammatory episodes, designated leprosy reactions, which represent the major cause of leprosy-associated irreversible neuropathy. There is currently no accurate, routine diagnostic test to reliably detect leprosy reactions, or to predict which patients will develop these immunological exacerbations. Identification of host biomarkers for leprosy reactions, particularly if correlating with early onset prior to development of clinical symptoms, will allow timely interventions that contribute to decreased morbidity. Development of a point-of-care (POC) test based on such correlates would be a definite game changer in leprosy health care. In this review, proteomic-, transcriptomic and metabolomic research strategies aiming at identification of host biomarker-based correlates of leprosy reactions are discussed, next to external factors associated with occurrence of these episodes. The vast diversity in research strategies combined with the variability in patient- and control cohorts argues for harmonisation of biomarker discovery studies with geographically overarching study sites. This will improve identification of specific correlates associated with risk of these damaging inflammatory episodes in leprosy and subsequent application to rapid field tests.

Discovery of 4 exonic and 1 intergenic novel susceptibility loci for leprosy

Seven new risk coding variants have been identified through an exome-wide association study (EWAS), which studied the contributions of protein-coding variants to leprosy susceptibility. But some potential susceptibility loci were not studied in the previous EWAS study because of the project consideration. Seventeen unstudied potential susceptibility loci of the previous EWAS were validated in 3169 cases and 9814 controls in this study. Four disease-associated exonic loci were identified: rs671 in ALDH2 (P = 2.0 × 10^-20 , odds ratio [OR] = 1.35), rs13259978 in SLC7A2 (P = 1.74 × 10^-8 , OR = 1.28), rs925368 in GIT2 (P = 9.18 × 10^-17 , OR = 1.44), and rs75680863 in TCN2 (P = 8.37 × 10^-21 , OR = 0.74). Potentially implicating ZFP36L1 as a new susceptibility gene, 1 intergenic single nucleotide polymorphism (SNP), rs1465788 (P = 7.81 × 10^-6 , OR = 0.88), was also suggested to be associated with leprosy. A luciferase reporter assay showed that the rs1465788 risk allele notably decreased the transcription activity of the flanking sequence. These findings suggest the possible involvement of lipid metabolism, NF-κB homeostasis and macrophage antimicrobial pathways in leprosy pathogenesis.

Type I Interferons, Autophagy and Host Metabolism in Leprosy

For those with leprosy, the extent of host infection by Mycobacterium leprae and the progression of the disease depend on the ability of mycobacteria to shape a safe environment for its replication during early interaction with host cells. Thus, variations in key genes such as those in pattern recognition receptors (NOD2 and TLR1), autophagic flux (PARK2, LRRK2, and RIPK2), effector immune cytokines (TNF and IL12), and environmental factors, such as nutrition, have been described as critical determinants for infection and disease progression. While parkin-mediated autophagy is observed as being essential for mycobacterial clearance, leprosy patients present a prominent activation of the type I IFN pathway and its downstream genes, including OASL, CCL2, and IL10. Activation of this host response is related to a permissive phenotype through the suppression of IFN-γ response and negative regulation of autophagy. Finally, modulation of host metabolism was observed during mycobacterial infection. Both changes in lipid and glucose homeostasis contribute to the persistence of mycobacteria in the host. M. leprae-infected cells have an increased glucose uptake, nicotinamide adenine dinucleotide phosphate generation by pentose phosphate pathways, and downregulation of mitochondrial activity. In this review, we discussed new pathways involved in the early mycobacteria–host interaction that regulate innate immune pathways or metabolism and could be new targets to host therapy strategies.

A pathway-based association analysis identified FMNL1-MAP3K14 as susceptibility genes for leprosy

The nuclear transcription factor-κB (NF-κB) plays a pivotal role in controlling both innate and adaptive immunity and regulates the expressions of many immunological mediators. Abundant evidences have showed the importance of NF-κB pathway in the host immune responses against Mycobacterium leprae in the development of leprosy. However, no particular association study between leprosy and NF-κB pathway-related gene polymorphisms was reported. Here, we performed a large-scale and two-stage candidate association study to investigate the association between 94 NF-κB pathway-related genes and leprosy. Our results showed that rs58744688 was significantly associated with leprosy (P = 7.57 × 10-7 , OR = 1.12) by combining the previous genomewide association data sets and four independent validation sample series, consisting of a total of 4631 leprosy cases and 6413 healthy controls. This founding implicated that MAP3K14 and FMNL1 were susceptibility genes for leprosy, which suggested the involvement of macrophage targeting and NF-κB pathway in the development of leprosy.

High glucose induces O-GlcNAc glycosylation of the vitamin D receptor (VDR) in THP1 cells and in human macrophages derived from monocytes

Chronic hyperglycemia increases the carbon flux through the hexosamine pathway, allowing the accumulation of UDP-GlcNAc. UDP-GlcNAc is the sugar donor for the enzyme-mediated protein glycosylation event known as OGlcNAcylation. This posttranslational modification targets several transcription factors implicated in glucose toxicity, insulin resistance, and diabetes. Vitamin D plays an important role in glucose homeostasis and insulin secretion through transcriptional mechanisms mediated by its receptor (VDR). Vitamin D deficiency has been associated with higher susceptibility to bacterial diseases in diabetic patients. However, it has not been explored whether VDR is subject to OGlcNAcylation or whether high glucose affects its transcriptional or biological activities. The aim of this study was to evaluate the effect of hyperglycemia on VDR OGlcNAcylation and its effects on vitamin D-mediated transcription. We predicted potential OGlcNAcylation sites using free software. Our results showed that hyperglycemia (30 mM) induces the OGlcNAcylation of VDR in THP1 cells and in human macrophages derived from monocytes (MDM). This condition did not hamper the vitamin D-dependent activation of LL-37 gene expression, and even did not impair the macrophage bactericidal activity. Our study provides new insight into vitamin D receptor posttranslational modification that may have relevance on the physiological responses of long-term hyperglycemia.

Genetic polymorphisms of the IL6 and NOD2 genes are risk factors for inflammatory reactions in leprosy

The pathways that trigger exacerbated immune reactions in leprosy could be determined by genetic variations. Here, in a prospective approach, both genetic and non-genetic variables influencing the amount of time before the development of reactional episodes were studied using Kaplan-Meier survival curves, and the genetic effect was estimated by the Cox proportional-hazards regression model. In a sample including 447 leprosy patients, we confirmed that gender (male), and high bacillary clinical forms are risk factors for leprosy reactions. From the 15 single nucleotide polymorphisms (SNPs) at the 8 candidate genes genotyped (TNF/LTA, IFNG, IL10, TLR1, NOD2, SOD2, and IL6) we observed statistically different survival curves for rs751271 at the NOD2 and rs2069845 at the IL6 genes (log-rank p-values = 0.002 and 0.023, respectively), suggesting an influence on the amount of time before developing leprosy reactions. Cox models showed associations between the SNPs rs751271 at NOD2 and rs2069845 at IL6 with leprosy reactions (HRGT = 0.45, p = 0.002; HRAG = 1.88, p = 0.0008, respectively). Finally, IL-6 and IFN-γ levels were confirmed as high, while IL-10 titers were low in the sera of reactional patients. Rs751271-GT genotype-bearing individuals correlated (p = 0.05) with lower levels of IL-6 in sera samples, corroborating the genetic results. Although the experimental size may be considered a limitation of the study, the findings confirm the association of classical variables such as sex and clinical forms with leprosy, demonstrating the consistency of the results. From the results, we conclude that SNPs at the NOD2 and IL6 genes are associated with leprosy reactions as an outcome. NOD2 also has a clear functional pro-inflammatory link that is coherent with the exacerbated responses observed in these patients.

Polymorphisms in genes TLR1, 2 and 4 are associated with differential cytokine and chemokine serum production in patients with leprosy

BACKGROUND

Leprosy or hansen's disease is a spectral disease whose clinical forms mostly depends on host's immune and genetic factors. Different Toll-like receptors (TLR) variants have been described associated with leprosy, but with some lack of replication across different populations.

OBJECTIVES

To evaluate the role of polymorphisms in genes TLR1, TLR2 and TLR4 and susceptibility to leprosy in a genetic case control study; to verify the association between genotypes of these markers and the immunological profile in the serum of patients with leprosy.

METHODS

Pre-designed TaqMan® assays were used to genotype markers at TLR1 (rs4833095, rs5743551), TLR2 (rs7656411, rs3804099) and TLR4 (rs1927914, rs1927911). A panel of cytokines and chemokines was accessed by enzime-linked immunosorbent assay (ELISA) test in the serum of a subgroup of patients with and without leprosy reactions.

FINDINGS

Our results show an association between the T allele of rs3804099 at the TLR2 gene and increased risk for leprosy per se [Odds ratio (OR) = 1.296, p = 0,022]. In addition, evaluating the association between different genotypes of the TLR1, 2 and 4 markers and cytokine/chemokine serological levels, IL-17 appears as an immunological marker regulated by the polymorphism of the three TLR genes evaluated, whereas different TLR1 genotypes were associated with differential production of IL-12p40 and MCP-1(CCL2). Furthermore, other relevant serum markers such as CXCL-10 and IL-6 seemed to be regulated by TLR2 variants and IL-1β was related to TLR4 genotypes.

MAIN CONCLUSIONS

All together our data points that the tested TLR markers may have a regulatory role in the immunity against Mycobacterium leprae, by driving the host's production of key cytokines and chemokines involved in the pathogenesis of this disease.

Investigation of a Medieval Pilgrim Burial Excavated from the Leprosarium of St Mary Magdalen Winchester, UK

We have examined the remains of a Pilgrim burial from St Mary Magdalen, Winchester. The individual was a young adult male, aged around 18–25 years at the time of death. Radiocarbon dating showed the remains dated to the late 11^th–early 12^th centuries, a time when pilgrimages were at their height in Europe. Several lines of evidence in connection with the burial suggested this was an individual of some means and prestige. Although buried within the leprosarium cemetery, the skeleton showed only minimal skeletal evidence for leprosy, which was confined to the bones of the feet and legs. Nonetheless, molecular testing of several skeletal elements, including uninvolved bones all showed robust evidence of DNA from Mycobacterium leprae, consistent with the lepromatous or multibacillary form of the disease. We infer that in life, this individual almost certainly suffered with multiple soft tissue lesions. Genotyping of the M.leprae strain showed this belonged to the 2F lineage, today associated with cases from South-Central and Western Asia. During osteological examination it was noted that the cranium and facial features displayed atypical morphology for northern European populations. Subsequently, geochemical isotopic analyses carried out on tooth enamel indicated that this individual was indeed not local to the Winchester region, although it was not possible to be more specific about their geographic origin.

This multidisciplinary research article, involving biomolecular analysis, osteology, strontium and oxygen isotopic analyses and archaeology, examines the remains of a Pilgrim burial excavated from the medieval leprosy hospital of St Mary Magdalen, Winchester, UK. Radiocarbon dating showed the remains dated to the late 11^th–early 12^th centuries, a time when pilgrimages were at their height in Europe. The leprosarium at Winchester is one of the earliest excavated examples from Western Europe and has been the subject of a series of recent academic papers. The site is remarkable for the high number of burials displaying skeletal lesions characteristic of leprosy (86%) and the state of preservation of biomolecular markers of the disease, including mycolipids and DNA. Genotyping of the M.leprae strain showed this belonged to the 2F lineage, today associated with cases from South-Central and Western Asia. Several aspects of the burial and dietary isotope analysis indicated this was an individual of some prestige and means; an unusual cranial morphology pointed to possible origin outside of the British Isles. Strontium and oxygen isotopic analyses confirmed he was not local to the Winchester area but were not able to pinpoint his precise origins. Overall these findings confirm the benefits of a multidisciplinary approach which allows investigation of the wider relationship between leprosy, medieval pilgrimage and M.leprae transmission.

Th9 cytokines response and its possible implications in the immunopathogenesis of leprosy

AIMS

Leprosy is an infectious-contagious disease whose clinical evolution depends on the interaction of the infectious agent with the immune response of the host, leading to a clinical spectrum that ranges from lepromatous leprosy (susceptibility, LL) to tuberculoid leprosy (resistance, TT). The immune response profile will depend on the pattern of cytokine production and on the activity of macrophages during infection. Classically, the clinical evolution of leprosy has been associated with Th1/Th2 cytokine profiles, but the role of new cytokine profiles such as T helper 9 (Th9) remains to be elucidated.

METHODS

To evaluate the tissue expression profile of these cytokines, a cross-sectional study was conducted using a sample of 30 leprosy skin lesion biopsies obtained from patients with leprosy, 16 TT and 14 lepromatous LL.

RESULTS

Immunohistochemical analysis revealed a significant difference in interleukin (IL)-9, IL-4 transforming growth factor (TGF)-β and IL-10 levels between the two groups. IL-9 was more expressed in TT lesions compared with LL lesions. Higher expression of IL-4, IL-10 and TGF-β was observed in LL compared with TT. IL-4, IL-10 and TGF-β tended to be negatively correlated with the expression of IL-9, indicating a possible antagonistic activity in tissue.

CONCLUSIONS

The results suggest that Th9 lymphocytes may be involved in the response to Mycobacterium leprae, positively or negatively regulating microbicidal activity of the local immune system in the disease.

The involvement of endothelial mediators in leprosy

Leprosy is a chronic infectious disease that requires better understanding since it continues to be a significant health problem in many parts of the world. Leprosy reactions are acute inflammatory episodes regarded as the central etiology of nerve damage in the disease. The activation of endothelium is a relevant phenomenon to be investigated in leprosy reactions. The present study evaluated the expression of endothelial factors in skin lesions and serum samples of leprosy patients. Immunohistochemical analysis of skin samples and serum measurements of VCAM-1, VEGF, tissue factor and thrombomodulin were performed in 77 leprosy patients and 12 controls. We observed significant increase of VCAM-1 circulating levels in non-reactional leprosy (p = 0.0009). The immunostaining of VEGF and tissue factor was higher in endothelium of non-reactional leprosy (p = 0.02 for both) than healthy controls. Patients with type 1 reaction presented increased thrombomodulin serum levels, compared with non-reactional leprosy (p = 0.02). In type 2 reaction, no significant modifications were observed for the endothelial factors investigated. The anti-inflammatory and antimicrobial activities of the endotfhelial factors may play key-roles in the pathogenesis of leprosy and should be enrolled in studies focusing on alternative targets to improve the management of leprosy and its reactions.

Mycobacterium leprae-induced Insulin-like Growth Factor I attenuates antimicrobial mechanisms, promoting bacterial survival in macrophages

Mycobacterium leprae (ML), the etiologic agent of leprosy, can subvert macrophage antimicrobial activity by mechanisms that remain only partially understood. In the present study, the participation of hormone insulin-like growth factor I (IGF-I) in this phenomenum was investigated. Macrophages from the dermal lesions of the disseminated multibacillary lepromatous form (LL) of leprosy expressed higher levels of IGF-I than those from the self-limited paucibacillary tuberculoid form (BT). Higher levels of IGF-I secretion by ML-infected macrophages were confirmed in ex vivo and in vitro studies. Of note, the dampening of IGF-I signaling reverted the capacity of ML-infected human and murine macrophages to produce antimicrobial molecules and promoted bacterial killing. Moreover, IGF-I was shown to inhibit the JAK/STAT1-dependent signaling pathways triggered by both mycobacteria and IFN-γ most probably through its capacity to induce the suppressor of cytokine signaling-3 (SOCS3). Finally, these in vitro findings were corroborated by in vivo observations in which higher SOCS3 expression and lower phosphorylation of STAT1 levels were found in LL versus BT dermal lesions. Altogether, our data strongly suggest that IGF-I contributes to the maintenance of a functional program in infected macrophages that suits ML persistence in the host, reinforcing a key role for IGF-I in leprosy pathogenesis.

In situ expression of M2 macrophage subpopulation in leprosy skin lesions

The clinical manifestations of the leprosy depend on host immune response and the macrophages are the primary cells involved in this process. M1 and M2 cells exhibited distinct morphology, distinct surface marker profiles, as well as different cytokine and chemokine secretion. Macrophages express receptors such as CD163, CD68, CD206, and costimulatory molecules such as CD80 and CD86, and cytokines that trigger a suppressive or inflammatory response. Thirty-three untreated patients were selected, 17 patients had the tuberculoid leprosy (TT) and 16 had the lepromatous leprosy (LL). We performed immunohistochemistry to detect IL-13, IL-10, TGF-β, FGF-β, CD163, CD68, arginase 1. M2 macrophages showed significant differences between the groups studied with increase in the expression of costimulatory molecules (CD68 and CD163), arginase 1 and cytokines (IL-10, IL-13, TGF-β and FGF-b) in the LL form. Response of M2 macrophages emerge as an alternative for a better understanding of the innate immunity in the polar forms of leprosy, highlighting the role of cytokines, arginase 1 and costimulatory molecules in the repair and suppressive responses in the lepromatous form of the disease.

Single Nucleotide Polymorphisms in IL17A and IL6 Are Associated with Decreased Risk for Pulmonary Tuberculosis in Southern Brazilian Population

In Mycobacterium tuberculosis (MTB) infection, the complex interaction of host immune system and the mycobacteria is associated with levels of cytokines production that play a major role in determining the outcome of the disease. Several single-nucleotide polymorphisms (SNPs) in cytokine genes have been associated with tuberculosis (TB) outcome. The aim of this study was to evaluate the association between previously reported SNPs IL2–330 T>G (rs2069762); IL4–590 C>T (rs2243250); IL6–174 G>C (rs1800795); IL10–592 A>C (rs1800872); IL10–1082 G>A (rs1800896); IL17A -692 C>T (rs8193036); IL17A -197 G>A (rs2275913); TNF -238 G>A (rs361525); TNF -308 G>A (rs1800629) and IFNG +874 T>A (rs2430561) and pulmonary TB (PTB) susceptibility. We conducted a case-control study in individuals from Southern Brazil who were recruited between February 2012 and October 2013 in a high incidence TB city. We performed a multiplex genotyping assay in 191 patients with PTB and 175 healthy subjects. Our results suggest a decreased risk for PTB development associated with the IL17A -197A allele (OR = 0.29; p = 0.04), AA genotype (OR = 0.12; p = 0.04) and A carrier (AG/AA) (OR = 0.29; p = 0.004) and IL6 -174C carrier (CC/CG) (OR = 0.46; p = 0.04). We could not properly analyze IL17A -692 C>T (rs8193036) and IFNG +874T>A due to genotypic inconsistencies and found no evidence of association for the IL2, IL4, IL10 and TNF polymorphisms and PTB. In conclusion, our results show a protective effect of IL17 and IL6 polymorphisms on PTB outcome in Southern Brazilian population.

The role of autophagy in modulation of neuroinflammation in microglia

Microglia have multiple functions in regulating homeostasis in the central nervous system (CNS), and microglial inflammation is thought to play a role in the etiology of the neurodegenerative diseases. When endogenous or exogenous stimuli trigger disorders in microenvironmental homeostasis in CNS, microglia critically determine the fate of other neural cells. Recently, it was reported that autophagy might influence inflammation and activation of microglia. Though the interaction between autophagy and macrophages has been reported and reviewed in length, the role of autophagy in microglia has yet to be reviewed. Herein, we will highlight recent advances on the emerging role of autophagy in microglia, focusing on the regulation of autophagy during microglial inflammation, and the possible mechanism involved.

Experimental models of leprosy

Leprosy (Hansen’s disease) is a chronic granulomatous bacterial disease which mainly affects skin and peripheral nervous system. Leprosy is caused by the obligate intercellular pathogen known as Mycobacterium leprae. Creating experimental models of leprosy is associated with serious problems due to biological characteristics of the pathogen. Numerous attempts to develop experimental models on different types of animals resulted in a few reproducible models on mice and nine-banded armadillos. Strains of knockout mice with genetic defects caused by site-directed mutagenesis are used as a basis for different leprosy models. Experimental models of leprosy are used for screening of anti-leprosy drugs, detection of drug resistance, studies on the pathogenesis of leprosy, production and evaluation of viability of M. leprae, developing of anti-leprosy vaccines.

Genetics of leprosy: Expected-and unexpected-developments and perspectives

A solid body of evidence produced over decades of intense research supports the hypothesis that leprosy phenotypes are largely dependent on the genetic characteristics of the host. The early evidence of a major gene effect controlling susceptibility to leprosy came from studies of familial aggregation, twins, and complex segregation analysis. Later, linkage and association analysis, first applied to the investigation of candidate genes and chromosomal regions and more recently, to genome-wide scans, have revealed several HLA and non-HLA gene variants as risk factors for leprosy phenotypes such as disease per se, its clinical forms, and leprosy reactions. In addition, powerful, hypothesis-free strategies such as genome-wide association studies have led to an exciting, unexpected development: Leprosy susceptibility genes seem to be shared with Crohn's and Parkinson's disease. Today, a major challenge is to find the exact variants causing the biological effect underlying the genetic associations. New technologies, such as Next Generation Sequencing-that allows, for the first time, the cost- and time-effective sequencing of a complete human genome-hold the promise to reveal such variants; thus, strategies can be developed to study the functional impact of these variants in the context of infection, hopefully leading to the development of new targets for leprosy treatment and prevention.

Role of vitamin D in cytotoxic T lymphocyte immunity to pathogens and cancer

The discovery of vitamin D receptor (VDR) expression in immune cells has opened up a new area of research into immunoregulation by vitamin D, a niche that is distinct from its classical role in skeletal health. Today, about three decades since this discovery, numerous cellular and molecular targets of vitamin D in the immune system have been delineated. Moreover, strong clinical associations between vitamin D status and the incidence/severity of many immune-regulated disorders (e.g. infectious diseases, cancers and autoimmunity) have prompted the idea of using vitamin D supplementation to manipulate disease outcome. While much is known about the effects of vitamin D on innate immune responses and helper T (T(H)) cell immunity, there has been relatively limited progress on the frontier of cytotoxic T lymphocyte (CTL) immunity--an arm of host cellular adaptive immunity that is crucial for the control of such intracellular pathogens as human immunodeficiency virus (HIV), tuberculosis (TB), malaria, and hepatitis C virus (HCV). In this review, we discuss the strong historical and clinical link between vitamin D and infectious diseases that involves cytotoxic T lymphocyte (CTL) immunity, present our current understanding as well as critical knowledge gaps in the realm of vitamin D regulation of host CTL responses, and highlight potential regulatory connections between vitamin D and effector and memory CD8 T cell differentiation events during infections.

B. Durães S, C. Cardoso C, Nunes Sarno E, G. Pacheco A, C. F. Lana F, Ozório Moraes M. Association of IL10 Polymorphisms and Leprosy: A Meta-Analysis

Leprosy is a chronic infectious disease that depends on the interplay of several factors. Single nucleotide polymorphisms (SNPs) in host immune related genes have been consistently suggested as participants in susceptibility towards disease. Interleukin-10 (IL-10) is a crucial immunomodulatory cytokine in mycobacterial pathogenesis and especially the -819C>T SNP (rs1800871) has been tested in several case-control studies indicating association with leprosy risk, although a recent consensus estimate is still missing. In this study, we evaluated the association of the -819C>T SNP and leprosy in two new Brazilian family-based populations. Then, we performed meta-analysis for this polymorphism summarizing published studies including these Brazilian family-based groups. Finally, we also retrieved published studies for other distal and proximal IL10 polymorphisms: -3575 T>A (rs1800890), -2849 G>A (rs6703630), -2763 C>A (rs6693899), -1082 G>A (rs1800896) and -592 C>A (rs1800872). Results from meta-analysis supported a significant susceptibility association for the -819T allele, with pooled Odds Ratio of 1.22 (CI = 1.11–1.34) and P-value = 3x10^–5 confirming previous data. This result remained unaltered after inclusion of the Brazilian family-based groups (OR = 1.2, CI = 1.10–1.31, P-value = 2x10^–5). Also, meta-analysis confirmed association of -592 A allele and leprosy outcome (OR = 1.24, CI = 1.03–1.50, P-value = 0.02). In support of this, linkage disequilibrium analysis in 1000 genomes AFR, EUR, ASN and AMR populations pointed to r² = 1.0 between the -592C>A and -819C>T SNPs. We found no evidence of association for the other IL10 polymorphisms analyzed for leprosy outcome. Our results reinforce the role of the -819C>T as a tag SNP (rs1800871) and its association with leprosy susceptibility.

Genetics of leprosy: expected and unexpected developments and perspectives

A solid body of evidence produced over decades of intense research supports the hypothesis that leprosy phenotypes are largely dependent on the genetic characteristics of the host. The early evidence of a major gene effect controlling susceptibility to leprosy came from studies of familial aggregation, twins, and Complex Segregation Analysis. Later, linkage and association analysis, first applied to the investigation of candidate genes and chromosomal regions and more recently, to genome-wide scans, have revealed several leukocyte antigen complex and nonleukocyte antigen complex gene variants as risk factors for leprosy phenotypes such as disease per se, its clinical forms and leprosy reactions. In addition, powerful, hypothesis-free strategies such as Genome-Wide Association Studies have led to an exciting, unexpected development: Leprosy susceptibility genes seem to be shared with Crohn's and Parkinson's diseases. Today, a major challenge is to find the exact variants causing the biological effect underlying the genetic associations. New technologies, such as Next Generation Sequencing that allows, for the first time, the cost and time-effective sequencing of a complete human genome, hold the promise to reveal such variants. Strategies can be developed to study the functional effect of these variants in the context of infection, hopefully leading to the development of new targets for leprosy treatment and prevention.

NOD2 and CCDC122-LACC1 genes are associated with leprosy susceptibility in Brazilians

Leprosy is a complex disease with phenotypes strongly influenced by genetic variation. A Chinese genome-wide association study (GWAS) depicted novel genes and pathways associated with leprosy susceptibility, only partially replicated by independent studies in different ethnicities. Here, we describe the results of a validation and replication study of the Chinese GWAS in Brazilians, using a stepwise strategy that involved two family-based and three independent case-control samples, resulting in 3,614 individuals enrolled. First, we genotyped a family-based sample for 36 tag single-nucleotide polymorphisms (SNPs) of five genes located in four different candidate loci: CCDC122-LACC1, NOD2, TNFSF15 and RIPK2. Association between leprosy and tag SNPs at NOD2 (rs8057431) and CCDC122-LACC1 (rs4942254) was then replicated in three additional, independent samples (combined OR(AA) = 0.49, P = 1.39e-06; OR(CC) = 0.72, P = 0.003, respectively). These results clearly implicate the NOD2 pathway in the regulation of leprosy susceptibility across diverse populations.

Inflammation is genetically implicated in Parkinson's disease

Inflammation has long been associated with the pathogenesis of Parkinson's disease (PD) but the extent to which it is a cause or consequence is sill debated. Over the past decade a number of genes have been implicated in PD. Relatively rare missense mutations in genes such as LRRK2, Parkin, SNCA and PINK1 are causative for familial PD whereas more common variation in genes, including LRRK2, SNCA and GBA, comprise risk factors for sporadic PD. Determining how the function of these genes and the proteins they encode are altered in PD has become a priority, as results will likely provide much needed insights into contributing causes. Accumulating evidence indicates that many of these genes function in pathways that regulate aspects of immunity, particularly inflammation, suggesting close associations between PD and immune homeostasis.

The complex relationships between microglia, alpha-synuclein, and LRRK2 in Parkinson's disease

The proteins alpha-synuclein (αSyn) and leucine rich repeat kinase 2 (LRRK2) are both key players in the pathogenesis of the neurodegenerative disorder Parkinson's disease (PD), but establishing a functional link between the two proteins has proven elusive. Research studies for these two proteins have traditionally and justifiably focused in neuronal cells, but recent studies indicate that each protein could play a greater pathological role elsewhere. αSyn is expressed at high levels within neurons, but they also secrete the protein into the extracellular milieu, where it can have broad ranging effects in the nervous system and relevance to disease etiology. Similarly, low neuronal LRRK2 expression and activity suggests that LRRK2-related functions could be more relevant in cells with higher expression, such as brain-resident microglia. Microglia are monocytic immune cells that protect neurons from noxious stimuli, including pathological αSyn species, and microglial activation is believed to contribute to neuroinflammation and neuronal death in PD. Interestingly, both αSyn and LRRK2 can be linked to microglial function. Secreted αSyn can directly activate microglia, and can be taken up by microglia for clearance, while LRRK2 has been implicated in the intrinsic regulation of microglial activation and of lysosomal degradation processes. Based on these observations, the present review will focus on how PD-associated mutations in LRRK2 could potentially alter microglial biology with respect to neuronally secreted αSyn, resulting in cell dysfunction and neurodegeneration.

Pre-miR-146a (rs2910164 G>C) single nucleotide polymorphism is genetically and functionally associated with leprosy

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.

In spite of the successful drug therapy, leprosy is still affecting people worldwide. It is well known that host genetic background influences leprosy development and that genetic variants have been associated with the disease. Therefore we conducted a study to evaluate the role of microRNAs (miRNAs) polymorphisms in leprosy. We observed that a polymorphism in miR-146a is associated with the risk to develop leprosy in Brazilians. Based on the analysis of clinical specimens, we found that the genetic variant was correlated with elevated levels of miR-146a and it is also a negative regulator of tumor necrosis factor (TNF), an important inflammatory mediator in the leprosy context. These findings provide tenable evidences that miR-146a is important in the control of gene expression during M. leprae infection and also may contribute with leprosy development by controlling TNF levels.