Association between STR -794 CATT5-8 and SNP -173 G/C polymorphisms in the MIF gene and Lepromatous Leprosy in Mestizo patients of western Mexico.

Lepromatous Leprosy (LL) is the most common presentation of leprosy in Mexico. LL patients are unable to activate an effective inflammatory response against Mycobacterium leprae probably due to the genetics of the host. Macrophage Migration Inhibitory Factor (MIF) is important to trigger inflammation processes. Two polymorphisms have been reported for human MIF: STR -794 CATT5-8 and SNP -173 G/C. 7-8 CATT repeats at -794 and the C allele at -173 increase the expression of MIF. We aim to determine the association between the polymorphisms in MIF gene and LL. We carried a case and controls study with 100 Mexican LL patients and 100 healthy subjects (HS). PCR was used for genotyping of STR -794 CATT5-8 polymorphism and PCR-RFLP for -173 G/C. We found that LL patients possess high -794 CATT repeats (47.1%) more often than HS (32.7%). In conclusion, a MIF polymorphism is associated with susceptibility to LL in Western Mexican population.

Association of TNF -1031 C/C as a potential protection marker for leprosy development in Amazonas state patients, Brazil.

Polymorphisms present in the TNF promoter region has shown to influence the gene transcription. Leprosy displays different clinical manifestations according to the immune responses of the individual infected with Mycobacterium leprae. In this study, we evaluated the single nucleotide polymorphisms (SNPs) -238 G/A (rs361525), -308 G/A (rs1800629), -857 C/T (rs1799724), -863 A/C (rs1800630) and -1031 T/C (rs1799964) in the promoter region of the TNF to see whether these SNPs influence host-susceptibility to leprosy and the different clinical manifestation. Nucleotide sequencing was performed with DNA samples from 108 leprosy patients and 253 control subjects. An association between -1031 C/C genotype and protection from leprosy was observed when leprosy patients were compared to controls (OR 0.11; 95% CI=0.01-0.82; p=0.012). The -857 C/T genotype may be associated with susceptibility to leprosy (OR=1.81; 95% CI=1.09-3.00; p=0.028). Similar genotype and allele frequencies for the SNPs -308 G/A and -238 G/A were observed between leprosy patients and control subjects. Altogether, TNF polymorphisms in the promoter region may be predictive of leprosy outcome.

FoxP3 provides competitive fitness to CD4⁺CD25⁺ T cells in leprosy patients via transcriptional regulation.

Leprosy is a chronic infectious disease caused by Mycobacterium leprae. FoxP3 have been shown to have important implications in various diseases. The present study describes the mechanism of action of FoxP3 in CD4⁺CD25⁺ T cells derived from leprosy patients. Increased molecular interactions of FoxP3 with histone deacetylases 7/9 in the nucleus of CD4⁺CD25⁺ T cells derived from borderline lepromatous leprosy/lepromatous leprosy (BL/LL) patients were found to be responsible for FoxP3-driven immune suppression activities during the progression of leprosy. Further, downregulation of CTLA-4 and CD25 genes in siFoxP3-treated PBMCs derived from BL/LL patients elucidated the transcription-activating nature of FoxP3. This observation was supported by direct binding of FoxP3 to the promoter region of the CTLA-4 and CD25 genes, and FoxP3's molecular interaction with histone acetyl transferases. The study also revealed that the increased expression of miR155 in CD4⁺CD25⁺ cells from BL/LL governs the competitive fitness of these cells. Again, reduced Annexin V & propidium iodide staining and Nur77 expression, and concomitantly increased Ki-67 positivity suggested that CD4⁺CD25⁺ cells derived from BL/LL patients are more competitively fit than those from borderline tuberculoid leprosy/tuberculoid leprosy and healthy controls. Taken together, the study shows the orchestration of FoxP3 leading to competitive fitness of Treg cells in leprosy.

IL-10 promoter SNPs and susceptibility to leprosy in ethnic groups from southwest China.

The purpose of this study was to determine whether interleukin-10 (IL-10) promoter polymorphisms are associated with leprosy or their subtypes in ethnic groups from southwest China. Genotyping using TaqMan® SNP Genotyping Master Mix and ABI 7500 real-time PCR system was performed for IL-10 T3575A, G2849A, C2763A, A1082G, C819T, and C592A in 189 healthy controls (40 ± 18 years) and 193 patients (46 ± 18 years) with leprosy [multibacillary, N = 131; paucibacillary (PB), N = 62]. The allelic frequencies of -2763C (97.9 vs 94.0%, P = 0.0074) and -1082A (92.8 vs 88.6%, P = 0.0452) in leprosy patients were significantly higher than in control subjects. The genetic frequency of -2763CC and -1082AA was not only significantly higher among leprosy patients than among control subjects [odds ratio (OR) = 3.33, 95% confidence interval (95%CI) = 1.39-7.99, P = 0.0071 and OR = 1.76, 95%CI = 1.02-3.03, P = 0.0420, respectively] but also significantly higher among PB patients than among control subjects (OR = 2.46, 95%CI = 1.22-4.96, P = 0.0115 and OR = 5.58, 95%CI = 2.06-15.12, P = 0.0007, respectively). The frequency of IL-10 haplotype 3575A/2849G/2763A/1082G/819C/592C was significantly higher among leprosy patients (OR = 5.57, 95%CI = 1.13-27.52, P = 0.0351) and PB patients (OR = 10.5, 95%CI = 1.36- 81.05, P = 0.0241) than among control subjects. IL-10 promoter -2763C/CC,-1082A/AA and haplotype 3575A/2849G/2763A/1082 G/819C/592C are associated with susceptibility to leprosy and the PB subtype in southwest China.

IL-10 gene promoter polymorphisms and leprosy in a Colombian population sample.

INTRODUCTION: Polymorphisms in promoters of genes code for cytokines that affect transcription levels. Several have been associated with leprosy patients that have functional and clinical implications. OBJECTIVE: Polymorphisms in the promoter of the IL10 gene of leprosy patients will be compared frequencies in normal population. MATERIALS AND METHODS: SNPs (single nucleotide polymorphism) -1082 A/G (rs1800896), -819C/T (rs1800871), and -592A/C (rs1800872) were identified in 100 leprosy patients and in a control group of 100 volunteers from a leprosy endemic region of Colombia. RESULTS: The genotypes C/C and C/T in the SNP -819 were associated together with leprosy (OR=4.34, p<0.001).Similarly, the genotypes C/C and C/A in the -592 SNP showed an association (OR=4.3, p<0.001). The haplotypes -819C-519C and -1082A-819C-592C showed significant association (OR=4.34, p<0.001 and OR=6.25, p<0.001) respectively. These haplotypes in homozygosis conditions were also associated with leprosy: -819C-519C/-819C-519C (OR=4.34, p<0.001), -1082A -819C-592C/-1082A -819C-592C (OR=1.90, p=0.04). The SNP -1082 was not associated with leprosy in this population. CONCLUSIONS: The haplotypes associated with leprosy, -1082A-819C-592C/-1082A-819C-592C, have been reported as low producers of IL-10. Functionally, the low production of IL-10 may have immune response consequences and clinical implications. Additional haplotypes of IL-10 have been reported as markers for leprosy susceptibility or resistance in other ethnic populations. This suggests that differences in distribution of diverse IL-10 gene polymorphisms among ethnic groups may indicate important gene-disease associations.

IL-10 gene promoter polymorphisms and leprosy in a Colombian population sample / Polimorfismos en el gen promotor de IL-10 en una muestra de pacientes colombianos con lepra

Introduction. Polymorphisms in promoters of genes code for cytokines that affect transcription levels. Several have been associated with leprosy patients that have functional and clinical implications. Objective. Polymorphisms in the promoter of the IL10 gene of leprosy patients will be compared frequencies in normal population. Materials and methods. SNPs (single nucleotide polymorphism) -1082 A/G (rs1800896), -819C/T (rs1800871), and -592A/C (rs1800872) were identified in 100 leprosy patients and in a control group of 100 volunteers from a leprosy endemic region of Colombia. Results. The genotypes C/C and C/T in the SNP -819 were associated together with leprosy (OR=4.34, p<0.001).Similarly, the genotypes C/C and C/A in the -592 SNP showed an association (OR=4.3, p<0.001). The haplotypes -819C-519C and -1082A-819C-592C showed significant association (OR=4.34, p<0.001 and OR=6.25, p<0.001) respectively. These haplotypes in homozygosis conditions were also associated with leprosy: -819C-519C/-819C-519C (OR=4.34, p<0.001), -1082A -819C-592C/-1082A -819C-592C (OR=1.90, p=0.04). The SNP -1082 was not associated with leprosy in this population. Conclusions. The haplotypes associated with leprosy, -1082A-819C-592C/-1082A-819C-592C, have been reported as low producers of IL-10. Functionally, the low production of IL-10 may have immune response consequences and clinical implications. Additional haplotypes of IL-10 have been reported as markers for leprosy susceptibility or resistance in other ethnic populations. This suggests that differences in distribution of diverse IL-10 gene polymorphisms among ethnic groups may indicate important gene-disease associations.

Introducción. Se han reportado polimorfismos en los genes promotores que codifican para citocinas y que afectan los niveles de transcripción, con implicaciones clínicas y funcionales en pacientes con lepra. Objetivo. Detectar los polimorfismos en el gen promotor de la interleucina 10 (IL-10), de los polimorfismos de un solo nucleótido (Single Nucleotide Polymorphisms, SNP) -1082 A/G (rs1800896), -819C/T (rs1800871) y -592A/C (rs1800872), en 100 pacientes con lepra y un grupo control de 100 voluntarios, de una región endémica de Colombia. Resultados. Los haplotipos -819C-519C y -1082A-819C-592C mostraron asociación significativa con lepra: OR=4,34, p=1 x 10-3, y OR=6,25, p=5 x 10-4, respectivamente. Estos haplotipos en condiciones de homocigoto, están también asociados con lepra: -819C-519C/-819C-519C (OR=4,34 p=1 x 10-3), -1082A -819C-592C/-1082A -819C-592C (OR=1,90 y p=0,04). El SNP -1082 no se encontró asociado con lepra en esta población. Los genotipos C/C y C/T en el SNP -819, se encontraron asociados a lepra (OR=4,34, p=1 x 10-3); de igual manera, los genotipos C/C y C/A en el SNP -592 mostraron asociación (OR=4,34, p=1 x 10-3). Conclusiones. El haplotipo que encontramos asociado con lepra, -1082A-819C-592C/-1082A-819C-592C, se ha relacionado con baja producción de IL-10. Funcionalmente, esta baja producción de IL-10 puede tener consecuencias en la respuesta inmunitaria, además de implicaciones clínicas. Se han reportado diferentes haplotipos de IL-10 como marcadores de vulnerabilidad y resistencia de lepra en otras poblaciones, lo cual sugiere que las diferencias en la distribución de diversos polimorfismos del gen de IL-10 entre grupos étnicos, es un factor importante al determinar la asociación entre enfermedad y genes.

Interferon-gamma receptor-1 gene promoter polymorphisms and susceptibility to leprosy in children of a single family.

The autosomal recessive disorder, because of a single mutation in interferon-γ receptor-1(IFNGR1) at position -56, was found to be associated with susceptibility to leprosy in children of the same family. The existence of such heterozygous carriers might explain the crucial role of IFNGR1 in the host defense against intracellular pathogens such as Mycobacterium leprae. The single nucleotide polymorphisms (SNPs) in major candidate genes, i.e., natural resistance-associated macrophage protein 1 (NRAMP1), vitamin D receptor (VDR), tumor necrosis factor-alpha (TNF-α), interleukin-10 (IL-10), interleukin-12-receptor 1 (IL-12R1), were not found to be associated with this disease.

Association of TNF, MBL, and VDR polymorphisms with leprosy phenotypes.

Although genetic variants in tumor necrosis factor (TNF), mannose binding lectin (MBL), and the vitamin D receptor (VDR) have been associated with leprosy clinical outcomes, these findings have not been extensively validated. We used a case-control study design with 933 patients in Nepal, which included 240 patients with type I reversal reaction (RR), and 124 patients with erythema nodosum leprosum (ENL) reactions. We compared genotype frequencies in 933 cases and 101 controls of seven polymorphisms, including a promoter region variant in TNF (G -308A), three polymorphisms in MBL (C154T, G161A and G170A), and three variants in VDR (FokI, BsmI, and TaqI). We observed an association between TNF -308A and protection from leprosy with an odds ratio of 0.52 (95% confidence interval = 0.29-0.95, p = 0.016). MBL polymorphism G161A was associated with protection from lepromatous leprosy (odds ratio = 0.33, 95% confidence interval = 0.12-0.85, p = 0.010). VDR polymorphisms were not associated with leprosy phenotypes. These results confirm previous findings of an association of TNF -308A with protection from leprosy and MBL polymorphisms with protection from lepromatous leprosy. The statistical significance was modest and will require further study for conclusive validation.

Genetic, epidemiological and biological analysis of interleukin-10 promoter single-nucleotide polymorphisms suggests a definitive role for -819C/T in leprosy susceptibility.

Leprosy is a complex infectious disease influenced by genetic and environmental factors. The genetic contributing factors are considered heterogeneous and several genes have been consistently associated with susceptibility like PARK2, tumor necrosis factor (TNF), lymphotoxin-alpha (LTA) and vitamin-D receptor (VDR). Here, we combined a case-control study (374 patients and 380 controls), with meta-analysis (5 studies; 2702 individuals) and biological study to test the epidemiological and physiological relevance of the interleukin-10 (IL-10) genetic markers in leprosy. We observed that the -819T allele is associated with leprosy susceptibility either in the case-control or in the meta-analysis studies. Haplotypes combining promoter single-nucleotide polymorphisms also implicated a haplotype carrying the -819T allele in leprosy susceptibility (odds ratio (OR)=1.40; P=0.01). Finally, we tested IL-10 production in peripheral blood mononuclear cells stimulated with Mycobacterium leprae antigens and found that -819T carriers produced lower levels of IL-10 when compared with non-carriers. Taken together, these data suggest that low levels of IL-10 during the disease outcome can drive patients to a chronic and unprotective response that culminates with leprosy.

Selection for unequal densities of sigma70 promoter-like signals in different regions of large bacterial genomes.

The evolutionary processes operating in the DNA regions that participate in the regulation of gene expression are poorly understood. In Escherichia coli, we have established a sequence pattern that distinguishes regulatory from nonregulatory regions. The density of promoter-like sequences, that could be recognizable by RNA polymerase and may function as potential promoters, is high within regulatory regions, in contrast to coding regions and regions located between convergently transcribed genes. Moreover, functional promoter sites identified experimentally are often found in the subregions of highest density of promoter-like signals, even when individual sites with higher binding affinity for RNA polymerase exist elsewhere within the regulatory region. In order to see the generality of this pattern, we have analyzed 43 additional genomes belonging to most established bacterial phyla. Differential densities between regulatory and nonregulatory regions are detectable in most of the analyzed genomes, with the exception of those that have evolved toward extreme genome reduction. Thus, presence of this pattern follows that of genes and other genomic features that require weak selection to be effective in order to persist. On this basis, we suggest that the loss of differential densities in the reduced genomes of host-restricted pathogens and symbionts is an outcome of the process of genome degradation resulting from the decreased efficiency of purifying selection in highly structured small populations. This implies that the differential distribution of promoter-like signals between regulatory and nonregulatory regions detected in large bacterial genomes confers a significant, although small, fitness advantage. This study paves the way for further identification of the specific types of selective constraints that affect the organization of regulatory regions and the overall distribution of promoter-like signals through more detailed comparative analyses among closely related bacterial genomes.

IL-10 promoter single nucleotide polymorphisms are significantly associated with resistance to leprosy.

The minor haplotype -3575A/-2849G/-2763C in IL-10 promoter has been defined as a marker of disease resistance to leprosy and its severity in Brazilian population. Our investigation of six single-nucleotide polymorphisms (SNPs) in IL-10 promoter in 282 Indian leprosy patients and 266 healthy controls by direct PCR sequencing, however, showed that the extended haplotype: -3575T/-2849G/-2763C/-1082A/-819C/-592C was associated with resistance to leprosy per se and to the development of severe form of leprosy, using either a binomial (controls vs cases, P=0.01, OR=0.58, CI=0.37-0.89) or ordinal (controls vs paucibacillary vs multibacillary, P=0.004) model. Whereas, IL-10 haplotype -3575T/-2849G/-2763C/-1082A/-819T/-592A was associated with the risk of development of severe form of leprosy (P=0.0002) in contrast to the minor risk haplotype -3575T/-2849A/-2763C in the Brazilian population. The role of IL-10 promoter SNPs in Brazilian and Indian population strongly suggests the involvement of IL-10 locus in the outcome of leprosy.

Interleukin-10 promoter single-nucleotide polymorphisms as markers for disease susceptibility and disease severity in leprosy.

We have determined IL-10 promoter genotypes of five single-nucleotide polymorphisms (SNPs): T-3575A, A-2849G, C-2763A, -A-1082G and C-819T. The haplotype frequencies were defined in healthy subjects compared to leprosy patients, and analyzed for their occurrence in multi- (MB) vs paucibacillary (PB) as severe and mild forms of leprosy, respectively. Haplotypes defined by three SNP positions (-3575, -2849 and -2763) captured significant differences between controls and patients (P=0.04). The haplotype carrying -3575A, -2849G and -2763C was associated with resistance to leprosy and to the development of severe forms of the disease using either a binomial (controls vs cases, P=0.005, OR=0.35, CI=0.13-0.91) or ordinal (controls vs PB vs MB, P=0.006, OR=0.32, CI=0.12-0.83) model. By contrast, the IL-10 haplotype -3575T/-2849A/-2763C was found to be associated with susceptibility to leprosy per se (P=0.027, OR=2.37, CI=1.04-5.39), but not leprosy type. The data suggest that the IL-10 locus contributes to the outcome of leprosy.

Is there a future for TNF promoter polymorphisms?

The in vitro study of TNF promoter polymorphism (SNP) function was stimulated by the numerous case-control (association) studies of the polymorphisms in relation to human disease and the appearance of several studies claiming to show a functional role for these SNPs provided a further impetus to researchers interested in the role of TNF in their disease of interest. In this review we consider case-control studies, concentrating on the autoimmune and inflammatory diseases rheumatoid arthritis, multiple sclerosis, ankylosing spondylitis, and asthma, and on infectious diseases including malaria, hepatitis B and C infection, leprosy and sepsis/septic shock. We also review the available evidence on the functional role of the various TNF promoter polymorphisms. In general, case-control studies have produced mixed results, with little consensus in most cases on whether any TNF polymorphisms are actually associated with disease, although results have been more consistent in the case of infectious diseases, particularly malaria. Functional studies have also produced mixed results but recent work suggests that the much studied -308G/A polymorphism is not functional, while the function of other TNF polymorphisms remains controversial. Studies of the TNF region are increasingly using extended haplotypes that can better capture the variation of the MHC region.

Identification of strong promoter elements of Mycobacterium smegmatis and their utility for foreign gene expression in mycobacteria.

The isolation of elements driving high-level expression of foreign genes in mycobacteria would significantly aid characterization of mycobacterial antigens and recombinant vaccine development. Mycobacterium smegmatis is a widely employed host for recombinant mycobacterial gene expression. This report describes the identification of strong promoter elements of M. smegmatis. Fluorescence-activated cell sorting was employed to isolate DNA fragments permitting high-level expression of the Aequorea victoria green fluorescent protein within recombinant M. smegmatis. Ten postulated M. smegmatis promoters were identified which showed activity two to six times that of the strong beta-lactamase promoter of Mycobacterium fortuitum. The utility of one of these promoters for the over-expression of foreign genes in mycobacteria was demonstrated by the efficient purification of the Mycobacterium leprae 35-kDa antigen from recombinant M. smegmatis.

Role of tumor necrosis factor-alpha and interleukin-10 promoter gene polymorphisms in leprosy.

Single-nucleotide polymorphisms within the genes coding for tumor necrosis factor (TNF)-alpha and interleukin (IL)-10 have been associated with several infectious diseases. To determine whether such polymorphisms are associated with leprosy, genotyping was performed at the -308 and -238 positions of the promoter of the TNF-alpha gene in 210 and 191 patients with multibacillary (MB) leprosy, respectively; 90 and 79 patients with paucibacillary (PB) leprosy; and 92 control subjects. For the -592 and -819 positions within the promoter of the IL-10 gene, 143 patients with MB leprosy, 79 patients with PB leprosy, and 62 control subjects were included in the analysis. TNF2 allele frequency was significantly higher among control subjects than among all patients with leprosy or in the MB group (P<.05 and P<.01). For the IL-10 gene, the frequency of the homozygous -819TT genotype was significantly higher among patients than among control subjects. These data indicate that a relationship exists between TNF-alpha and IL-10 promoter polymorphisms and the development of PB leprosy.

Expression of foreign genes in Mycobacterium bovis BCG strains using different promoters reveals instability of the hsp60 promoter for expression of foreign genes in Mycobacterium bovis BCG strains.

SETTING: Optimization of BCG as a vehicle for live recombinant vaccines requires improved strategies for stable antigen expression. OBJECTIVES: To investigate the effects of various combinations of post-translational signals and promoters on expression and stability in different BCG strains. DESIGN: Plasmids were constructed using mycobacterial promoters (hsp60, 19-kDa antigen, 85A antigen--from the Mycobacterium tuberculosis complex--and the 18-kDa antigen from Mycobacterium leprae) and post-translation signals (85A antigen secretion and 19-kDa antigen acylation signals), coupled with reporter genes. RESULTS: The 19-kDa acylation signal had little effect on expression, while the 85A secretion signal enhanced markedly the levels of cell-associated product. Inclusion of the hsp60 promoter caused plasmid instability; various deletions affecting the promoter region occurred during or soon after transformation, but not during subsequent growth of the transformants, nor with other promoters. BCG Moreau appeared to be more susceptible to deletions than other BCG strains. CONCLUSIONS: The 85A signal may prove useful in optimizing gene expression in BCG, irrespective of secretion of the product. Deletions associated with the hsp60 promoter may be due to a transient lethal induction of the hsp60 promoter associated with electroporation. With intact plasmid there was no marked difference in expression between BCG strains.

Identification and characterization of the dnaA upstream region of Thermus thermophilus.

The gene order in the dnaA region of Thermus thermophilus was determined. Previously, we showed that the putative oriC of T. thermophilus is located in the dnaA-dnaN intergenic region. In the 4 kb region upstream of the dnaA gene four ORFs were found, all orientated in the same direction which is opposite to that of dnaA. The ORFs were identified as T. thermophilus homologs of gidA, gidB, soj and spo0J of Bacillus subtilis. The gene order spo0J-soj-gidB-gidA-dnaA-dnaN resembles that of B. subtilis, Pseudomonas putida, Coxiella burnetii, Streptomyces coelicolor, Mycobacterium leprae, and Mycobacterium tuberculosis. We identified the transcriptional start point of the dnaA gene. The -10 region shows significant homology to the Escherichia coli -10 consensus sequence. The putative -35 region shows homology neither to the E. coli -35 consensus sequence nor to known -35 sequences of T. thermophilus. There are no DnaA boxes in the promoter region, and consequently dnaA transcription is not repressed by DnaA protein in vitro, i.e. the dnaA gene of T. thermophilus is not autoregulated.

Tumor necrosis factor promoter polymorphism and susceptibility to lepromatous leprosy.

Genetically determined differences in immune responses to environmental agents may underlie susceptibility to many autoimmune and infectious diseases. Leprosy provides an example of a polarity in the type of immune response made to an infectious agent, and there is evidence that the major histocompatibility complex is genetically linked to leprosy type. It was found that HLA-DR2 is associated with both tuberculoid and lepromatous types of leprosy; however, a variant at position -308 of the promoter of the neighboring tumor necrosis factor (TNF) gene was increased in frequency in lepromatous (odds ratio = 3.0, P = .02) but not tuberculoid leprosy. Some studies have found higher serum levels of TNF in lepromatous than tuberculoid leprosy, and high TNF levels are found in malaria and leishmaniasis, which are also associated with this TNF allele. It is speculated that this association reflects genetic variability in cytokine production, which influences the immune response to and clinical outcome of leprosy.