Leonam Gomes Coutinho

The kynurenine pathway is involved in bacterial meningitis

BackgroundBacterial meningitis (BM) is characterized by an intense host inflammatory reaction, which contributes to the development of brain damage and neuronal sequelae. Activation of the kynurenine (KYN) pathway (KP) has been reported in various neurological diseases as a consequence of inflammation. Previously, the KP was shown to be activated in animal models of BM, and the association of the SNP AADAT + 401C/T (kynurenine aminotransferase II - KAT II) with the host immune response to BM has been described. The aim of this study was to investigate the involvement of the KP during BM in humans by assessing the concentrations of KYN metabolites in the cerebrospinal fluid (CSF) of BM patients and their relationship with the inflammatory response compared to aseptic meningitis (AM) and non-meningitis (NM) groups.MethodsThe concentrations of tryptophan (TRP), KYN, kynurenic acid (KYNA) and anthranilic acid (AA) were assessed by HPLC from CSF samples of patients hospitalized in the Giselda Trigueiro Hospital in Natal (Rio Grande do Norte, Brazil). The KYN/TRP ratio was used as an index of indoleamine 2,3-dioxygenase (IDO) activity, and cytokines were measured using a multiplex cytokine assay. The KYNA level was also analyzed in relation to AADAT + 401C/T genotypes.ResultsIn CSF from patients with BM, elevated levels of KYN, KYNA, AA, IDO activity and cytokines were observed. The cytokines INF-γ and IL-1Ra showed a positive correlation with IDO activity, and TNF-α and IL-10 were positively correlated with KYN and KYNA, respectively. Furthermore, the highest levels of KYNA were associated with the AADAT + 401 C/T variant allele.ConclusionThis study suggests a downward modulatory effect of the KP on CSF inflammation during BM.

Association of kynurenine aminotransferase II gene C401T polymorphism with immune response in patients with meningitis

BackgroundThe kynurenine (KYN) pathway has been shown to be altered in several diseases which compromise the central nervous system (CNS) including infectious diseases such as bacterial meningitis (BM). The aim of this study was to assess single nucleotide polymorphisms (SNPs) in four genes of KYN pathway in patients with meningitis and their correlation with markers of immune response in BM.MethodsOne hundred and one individuals were enrolled in this study to investigate SNPs in the following genes: indoleamine-2,3-dioxygenase (IDO1 gene), kynureninase (KYNU gene), kynurenine aminotransferase I (CCBL1 gene), and kynurenine aminotransferase II (AADAT gene). SNP analyses were performed by primer-introduced restriction analysis-PCR (PIRA-PCR) followed by RFLP. Cytokines were measured using multiplex bead assay while immunoglobulins (IG) by immunodiffusion plates and NF-kappaB and c-Jun by dot blot assay.ResultsThe variant allele of SNP AADAT+401C/T showed prevalent frequency in patients with BM. A significant decrease (p < 0.05) in TNF-α, IL-1β, IL-6, MIP-1αCCL3 and MIP-1β/CCL4 levels was observed in BM patients homozygous (TT) to the SNP AADAT+401C/T. Furthermore, a significant (p < 0.05) decrease in cell count was observed in cerebrospinal fluid (CSF) from patients with TT genotype. In addition, an increase in the IgG level in adults (p < 0.05) was observed. The variant allele for KYNU+715G/A was found with low frequency in the groups, and the SNPs in IDO1+434T/G, KYNU+693G/A, CCBL1+164T/C, and AADAT+650C/T had no frequency in this population.ConclusionsThis study is the first report of an association of SNP AADAT+401C/T with the host immune response to BM, suggesting that this SNP may affect the host ability in recruitment of leukocytes to the infection site. This finding may contribute to identifying potential targets for pharmacological intervention as adjuvant therapy for BM.

SNPs in DNA repair genes associated to meningitis and host immune response

In vitro and in animal models, APE1, OGG1, and PARP-1 have been proposed as being involved with inflammatory response. In this work, we have investigated if the SNPs APE1 Asn148Glu, OGG1 Ser326Cys, and PARP-1 Val762Ala are associated to meningitis. The patient genotypes were investigated by PIRA-PCR or PCR-RFLP. DNA damages were detected in genomic DNA by Fpg treatment. IgG and IgA were measured from plasma and the cytokines and chemokines were measured from cerebrospinal fluid samples using Bio-Plex assays. A higher frequency (P<0.05) of APE1 Glu allele in bacterial meningitis (BM) and aseptic meningitis (AM) patients was observed. The genotypes Asn/Asn in control group and Asn/Glu in BM group was also higher. For the SNP OGG1 Ser326Cys, the genotype Cys/Cys was more frequent (P<0.05) in BM group. The frequency of PARP-1 Val/Val genotype was higher in control group (P<0.05). The occurrence of combined SNPs is significantly higher in BM patients, indicating that these SNPs may be associated to the disease. Increasing in sensitive sites to Fpg was observed in carriers of APE1 Glu allele or OGG1 Cys allele, suggesting that SNPs affect DNA repair activity. Alterations in IgG production were observed in the presence of SNPs APE1 Asn148Glu, OGG1 Ser326Cys or PARP-1 Val762Ala. Moreover, reduction in the levels of IL-6, IL-1Ra, MCP-1/CCL2 and IL-8/CXCL8 was observed in the presence of APE1 Glu allele in BM patients. In conclusion, we obtained indications of an effect of SNPs in DNA repair genes on the regulation of immune response in meningitis.

Polysaccharides from the fungus Scleroderma nitidum with anti-inflammatory potential modulate cytokine levels and the expression of Nuclear Factor kB

Several pharmacological properties are attributed to polysaccharides and glucans derived from fungi such as tumor, anti-inflammatory, and immunomodulatory activity. In this work, the anti-inflammatory potential of polysaccharides from the fungus Scleroderma nitidum and their possible action mechanism were studied. The effect of these polymers on the inflammatory process was tested using the carrageenan and histamine-induced paw edema model and the sodium thioglycolate and zymosan-induced model. The polysaccharides from S. nitidum were effective in reducing edema (73% at 50 mg/kg) and cell infiltrate (37% at 10 mg/kg) in both inflammation models tested. Nitric oxide, a mediator in the inflammatory process, showed a reduction of around 26% at 10 mg/kg of body weight. Analysis of pro-and anti-inflammatory cytokines showed that in the groups treated with polysaccharides from S. nitidum there was an increase in cytokines such as IL-1ra, IL-10, and MIP-1β concomitant with the decrease in INF-γ (75%) and IL-2 (22%). We observed the influence of polysaccharides on the modulation of the expression of nuclear factor κB. This compound reduced the expression of NF-κB by up to 64%. The results obtained suggest that NF-κB modulation an mechanisms that explain the anti-inflammatory effect of polysaccharides from the fungus S. nitidum.

Polymorphisms in DNA Repair Gene XRCC1 (Arg194Trp) and (Arg399Gln) and their Role in the susceptibility of Bacterial Meningitis

Meningitis is a contagious infectious disease with high rates of mortality. Most pathogenic microbes in humans have the ability to cause bacterial meningitis. However, the most common pathogens are Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae type b (Hib). It was found that the susceptibility to this infectious disease may be related to genetic characteristics of the host, such as the occurrence of single nucleotide polymorphisms (SNPs). In our previous work, association of SNPs in DNA repair genes with bacterial meningitis (BM) was demonstrated. In this study we evaluated two non-synonymous SNPs of the repair gene XRCC1 Arg194Trp (rs 1799782) and Arg399Gln (rs 25487) in patients with BM and health volunteers. The patient genotypes were investigated by PCR-RFLP. DNA damages were quantified using the genomic DNA with formamidopyrimidine DNA-glycosylase (FPG). Cytokines and chemokines were quantified from cerebrospinal fluid samples from BM patients. Concerning the SNP XRCC1 Arg194Trp, none association was found relation to BM. However, a higher frequency of heterozygous genotype for XRCC1 Arg399Gln was observed in the control group compared to the BM group (P=0.043; OR=0.426). DNA damage and cytokine/chemokines levels were not positively correlated with polymorphic genotypes. In conclusion, there is an indication that the SNP XRCC1 Arg399Gln could have a possible protective effect against BM.

Resveratrol decreases the expression of genes involved in inflammation through transcriptional regulation

ABSTRACT Oxidative stress generated during inflammation is associated with a wide range of pathologies. Resveratrol (RESV) displays anti‐inflammatory and antioxidant activities, being a candidate for the development of adjuvant therapies for several inflammatory diseases. Despite this potential, the cellular responses induced by RESV are not well known. In this work, transcriptomic analysis was performed following lipopolysaccharide (LPS) stimulation of monocyte cultures in the presence of RESV. Induction of an inflammatory response was observed after LPS treatment and the addition of RESV led to decreases in expression of the inflammatory mediators, tumor necrosis factor‐alpha (TNF‐&agr;), interleukin‐8 (IL‐8), and monocyte chemoattractant protein‐1 (MCP‐1), without cytotoxicity. RNA sequencing revealed 823 upregulated and 2098 downregulated genes (cutoff ≥2.0 or ≤−2.0) after RESV treatment. Gene ontology analysis showed that the upregulated genes were associated with metabolic processes and the cell cycle, consistent with normal cell growth and differentiation under an inflammatory stimulus. The downregulated genes were associated with inflammatory responses, gene expression, and protein modification. The prediction of master regulators using the iRegulon tool showed nuclear respiratory factor 1 (NRF1) and GA‐binding protein alpha subunit (GABPA) as the main regulators of the downregulated genes. Using immunoprecipitation and protein expression assays, we observed that RESV was able to decrease protein acetylation patterns, such as acetylated apurinic/apyrimidinic endonuclease‐1/reduction‐oxidation factor 1 (APE1/Ref‐1), and increase histone methylation. In addition, reductions in p65 (nuclear factor‐kappa B (NF‐&kgr;B) subunit) and lysine‐specific histone demethylase‐1 (LSD1) expression were observed. In conclusion, our data indicate that treatment with RESV caused significant changes in protein acetylation and methylation patterns, suggesting the induction of deacetylase and reduction of demethylase activities that mainly affect regulatory cascades mediated by NF‐&kgr;B and Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling. NRF1 and GABPA seem to be the main regulators of the transcriptional profile observed after RESV treatment. Graphical abstract Figure. No Caption available. HighlightsResveratrol is associated with decreased inflammatory modulator levels.Resveratrol induces significant changes in transcriptional control.Resveratrol decreases protein acetylation and increases methylation of H3K9.APE1/Ref‐1 acetylation is reduced after resveratrol treatment.NRF1 and GABPA seem to be the main regulators of resveratrol treatment.

Nutraceutical preconditioning with arginine and oil mixes. Effects on inflammatory mediators, oxidative stress and lipid profile in patients undergoing radical prostatectomy

PURPOSE To investigate whether there is any effect resulting from preconditioning with nutraceutical supplementation containing arginine and oil mixes with high ω9:ω6 ratio and low ω6:ω3 ratio containing EPA and DHA, ALA fatty acids on inflammatory mediators, antioxidant and lipid profile modulation in surgical trauma. METHODS Twenty-six men scheduled for radical prostatectomy were randomized into three groups and treated as follows: Group 1 (skim milk, 0% fat), Group 2 (supplement with ω6:ω3 ratio of 8:1 and arginine) and Group 3 (supplement with high ω9:ω6 ratio of 3.2:1 and low ω6:ω3 ratio of 1.4:1 and arginine). Patients received skin milk or supplements twice a day (200 ml) during five days prior to surgery. Peripheral venous blood samples were collected at three different timepoints: five days before surgery (PRE), before anesthesia induction (IND) and on the 2nd postoperative day (POS). Parameters analyzed included inflammatory cytokines (IL-1β, IL-6, IL-8 and TNF-α), antioxidants (catalase), lipid profile and heat shock protein (HSP-27). RESULTS There were no significant differences between groups on inflammatory mediators and antioxidant parameters. However, lipid profile values (Cholesterol, LDL, Triglycerides, VLDL), were significantly different. CONCLUSION Preconditioning with arginine and oil mixes containing high ω9:ω6 ratio and low ω6:ω3 ratio, has no effects on inflammatory mediators and oxidative stress in patients undergoing radical prostatectomy. Reduction of cholesterol, triglycerides, LDL and VLDL profiles may be related to the trauma effect.