RESUMO
Background: Oxidized lipid mediators such as eicosanoids play a central role in the inflammatory response associated with tuberculosis (TB) pathogenesis. Diabetes mellitus (DM) leads to marked changes in lipid mediators in persons with TB. However, the associations between diabetes-related changes in lipid mediators and clearance of M. tuberculosis (Mtb) among persons on anti-TB treatment (ATT) are unknown. Quantification of urinary eicosanoid metabolites can provide insights into the circulating lipid mediators involved in Mtb immune responses. Methods: We conducted a multi-site prospective observational study among adults with drug-sensitive pulmonary TB and controls without active TB; both groups had sub-groups with or without dysglycemia at baseline. Participants were enrolled from RePORT-Brazil (Salvador site) and RePORT-South Africa (Durban site) and stratified according to TB status and baseline glycated hemoglobin levels: a) TB-dysglycemia (n=69); b) TB-normoglycemia (n=64); c) non-TB/dysglycemia (n=31); d) non-TB/non-dysglycemia (n=29). We evaluated the following urinary eicosanoid metabolites: 11α-hydroxy-9,15-dioxo-2,3,4,5-tetranor-prostane-1,20-dioic acid (major urinary metabolite of prostaglandin E2, PGE-M), tetranor-PGE1 (metabolite of PGE2, TN-E), 9α-hydroxy-11,15-dioxo-2,3,4,5-tetranor-prostane-1,20-dioic acid (metabolite of PGD2, PGD-M), 11-dehydro-thromboxane B2 (11dTxB2), 2,3-dinor-6-keto-PGF1α (prostaglandin I metabolite, PGI-M), and leukotriene E4 (LTE4). Comparisons between the study groups were performed at three time points: before ATT and 2 and 6 months after initiating therapy. Results: PGE-M and LTE4 values were consistently higher at all three time-points in the TB-dysglycemia group compared to the other groups (p<0.001). In addition, there was a significant decrease in PGI-M and LTE4 levels from baseline to month 6 in the TB-dysglycemia and TB-normoglycemia groups. Finally, TB-dysglycemia was independently associated with increased concentrations of PGD-M, PGI-M, and LTE4 at baseline in a multivariable model adjusting for age, sex, BMI, and study site. These associations were not affected by HIV status. Conclusion: The urinary eicosanoid metabolite profile was associated with TB-dysglycemia before and during ATT. These observations can help identify the mechanisms involved in the pathogenesis of TB-dysglycemia, and potential biomarkers of TB treatment outcomes, including among persons with dysglycemia.
Assuntos
Mycobacterium tuberculosis , Tuberculose Pulmonar , Adulto , Dinoprostona , Eicosanoides , Humanos , África do Sul , Tuberculose Pulmonar/tratamento farmacológicoRESUMO
Cysteinyl leukotrienes (CysLTs) and lipoxins (LXs) are lipid mediators that control inflammation, with the former inducing and the latter inhibiting this process. Because the role played by these mediators in paracoccidioidomycosis was not investigated, we aimed to characterize the role of CysLT in the pulmonary infection developed by resistant (A/J) and susceptible (B10.A) mice. 48 h after infection, elevated levels of pulmonary LTC4 and LXA4 were produced by both mouse strains, but higher levels were found in the lungs of susceptible mice. Blocking the CysLTs receptor by MTL reduced fungal loads in B10.A, but not in A/J mice. In susceptible mice, MLT treatment led to reduced influx of PMN leukocytes, increased recruitment of monocytes, predominant synthesis of anti-inflammatory cytokines, and augmented expression of 5- and 15-lipoxygenase mRNA, suggesting a prevalent LXA4 activity. In agreement, MTL-treated macrophages showed reduced fungal burdens associated with decreased ingestion of fungal cells. Furthermore, the addition of exogenous LX reduced, and the specific blockade of the LX receptor increased the fungal loads of B10.A macrophages. This study showed for the first time that inhibition of CysLTs signaling results in less severe pulmonary paracoccidioidomycosis that occurs in parallel with elevated LX activity and reduced infection of macrophages.
Assuntos
Lipoxinas/metabolismo , Macrófagos Alveolares/imunologia , Macrófagos Alveolares/microbiologia , Paracoccidioides/patogenicidade , Paracoccidioidomicose/etiologia , Acetatos/farmacologia , Animais , Araquidonato 5-Lipoxigenase/deficiência , Araquidonato 5-Lipoxigenase/genética , Ciclopropanos , Dinoprostona/biossíntese , Mediadores da Inflamação/metabolismo , Antagonistas de Leucotrienos/farmacologia , Leucotrieno C4/biossíntese , Lipoxinas/biossíntese , Lipoxinas/imunologia , Macrófagos Alveolares/efeitos dos fármacos , Masculino , Camundongos , Camundongos da Linhagem 129 , Camundongos Endogâmicos A , Camundongos Knockout , Paracoccidioidomicose/tratamento farmacológico , Paracoccidioidomicose/imunologia , Quinolinas/farmacologia , Receptores de Leucotrienos/metabolismo , Receptores de Reconhecimento de Padrão/metabolismo , SulfetosRESUMO
The bioactive lipid mediator leukotriene B4 (LTB4) greatly enhances phagocyte antimicrobial functions against a myriad of pathogens. In murine histoplasmosis, inhibition of the LT-generating enzyme 5-lypoxigenase (5-LO) increases the susceptibility of the host to infection. In this study, we investigated whether murine resistance or susceptibility to Histoplasma capsulatum infection is associated with leukotriene production and an enhancement of in vivo and/or in vitro antimicrobial effector function. We show that susceptible C57BL/6 mice exhibit a higher fungal burden in the lung and spleen, increased mortality, lower expression levels of 5-LO and leukotriene B4 receptor 1 (BLT1) and decreased LTB4 production compared to the resistant 129/Sv mice. Moreover, we demonstrate that endogenous and exogenous LTs are required for the optimal phagocytosis of H. capsulatum by macrophages from both murine strains, although C57BL/6 macrophages are more sensitive to the effects of LTB4 than 129/Sv macrophages. Therefore, our results provide novel evidence that LTB4 production and BLT1 signaling are required for a histoplasmosis-resistant phenotype.
Assuntos
Histoplasma/imunologia , Histoplasmose/veterinária , Leucotrieno B4 , Receptores do Leucotrieno B4/imunologia , Doenças dos Roedores/imunologia , Animais , Araquidonato 5-Lipoxigenase/genética , Araquidonato 5-Lipoxigenase/imunologia , Suscetibilidade a Doenças , Inibidores Enzimáticos/farmacologia , Expressão Gênica/imunologia , Histoplasma/patogenicidade , Histoplasmose/genética , Histoplasmose/imunologia , Histoplasmose/metabolismo , Especificidade de Hospedeiro , Interações Hospedeiro-Patógeno , Leucotrieno B4/metabolismo , Leucotrieno B4/farmacologia , Pulmão/efeitos dos fármacos , Pulmão/imunologia , Pulmão/microbiologia , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Macrófagos/microbiologia , Camundongos , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Fagocitose/efeitos dos fármacos , Receptores do Leucotrieno B4/genética , Doenças dos Roedores/genética , Doenças dos Roedores/metabolismo , Transdução de Sinais , Baço/efeitos dos fármacos , Baço/imunologia , Baço/microbiologiaRESUMO
5-Lipoxygenase-derived products have been implicated in both the inhibition and promotion of chronic infection. Here, we sought to investigate the roles of endogenous 5-lipoxygenase products and exogenous leukotrienes during Histoplasma capsulatum infection in vivo and in vitro. 5-LO deficiency led to increased lung CFU, decreased nitric oxide production and a deficient primary immune response during active fungal infection. Moreover, H. capsulatum-infected 5-LO(-/-) mice showed an intense influx of neutrophils and an impaired ability to generate and recruit effector T cells to the lung. The fungal susceptibility of 5-LO(-/-) mice correlated with a lower rate of macrophage ingestion of IgG-H. capsulatum relative to WT macrophages. Conversely, exogenous LTB4 and LTC4 restored macrophage phagocytosis in 5-LO deficient mice. Our results demonstrate that leukotrienes are required to control chronic fungal infection by amplifying both the innate and adaptive immune response during histoplasmosis.
Assuntos
Araquidonato 5-Lipoxigenase/fisiologia , Histoplasma/imunologia , Histoplasmose/imunologia , Pulmão/imunologia , Macrófagos Peritoneais/imunologia , Linfócitos T/imunologia , Animais , Proliferação de Células , Células Cultivadas , Citotoxicidade Imunológica , Citometria de Fluxo , Histoplasmose/microbiologia , Histoplasmose/mortalidade , Imunidade Humoral , Imunidade Inata , Leucotrieno B4/metabolismo , Leucotrieno C4/metabolismo , Pulmão/microbiologia , Ativação Linfocitária , Macrófagos Peritoneais/citologia , Macrófagos Peritoneais/microbiologia , Camundongos , Camundongos Knockout , Óxido Nítrico/metabolismo , Fagocitose , Taxa de Sobrevida , Linfócitos T/microbiologiaRESUMO
Macrophages express P2X(7) and other nucleotide (P2) receptors, and display the phenomena of extracellular ATP (ATP(e))-induced P2X(7)-dependent membrane permeabilization and cell death by apoptosis and necrosis. P2X(7) receptors also cooperate with toll-like receptors (TLRs) to induce inflammasome activation and IL-1beta secretion. We investigated signaling pathways involved in the induction of cell death by ATP(e) in intraperitoneal murine macrophages. Apoptosis (hypodiploid nuclei) and necrosis (LDH release) were detected 6h after an induction period of 20 min in the presence of ATP. Apoptosis was blocked by caspase 3 and caspase 9 inhibitors and by cyclosporin A. The MAPK inhibitors PD-98059, SB-203580 and SB-202190 provoked no significant effect on apoptosis, but SB-203580 blocked LDH release. Neither apoptosis nor necrosis was inhibited when both intra- and extracellular Ca(2+) were chelated during the induction period. Mepacrine, a generic PLA(2) inhibitor and BEL, an inhibitor of Ca(2+)-independent PLA(2) (iPLA(2)) blocked apoptosis, while pBPB and AACOOPF(3), inhibitors of secretory and Ca(2+)-dependent PLA(2) respectively, had no significant effect. Cycloxygenase inhibitors had no effect on apoptosis, while the inhibitors of lipoxygenase (LOX) and leukotriene biosynthesis nordihydroguaiaretic acid (NDGA), zileuton, AA-861, and MK-886 significantly decreased apoptosis. Neither NDGA nor MK-886 blocked apoptosis of 5-LOX(-/-) macrophages. CP-105696 and MK-571, antagonists of leukotriene receptors, had no significant effect on apoptosis. None of the inhibitors of PLA(2) and LOX/leukotriene pathway had a significant inhibitory effect on LDH release. Our results indicate that a Ca(2+)-independent step involving an iPLA(2) and 5-LOX are involved in the triggering of apoptosis but not necrosis by P2X(7) in macrophages.
Assuntos
Trifosfato de Adenosina/farmacologia , Apoptose , Araquidonato 5-Lipoxigenase/metabolismo , Macrófagos/enzimologia , Fosfolipases A2 Independentes de Cálcio/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Cálcio/metabolismo , Morte Celular , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Quinases Ativadas por Mitógeno/metabolismoRESUMO
The meta 1 gene of Leishmania is conserved across the genus and encodes a protein upregulated in metacyclic promastigotes. Meta 1 constitutive overexpressing mutants show increased virulence to mice. In this paper, both meta 1 recombinant protein and plasmids bearing the meta 1 gene were tested for their antigenicity and potential for inducing protective immunity in mice. Vaccination with the recombinant protein induced a predominant Th2-type of response and did not result in protection upon challenge with live parasites. Surprisingly, the expected reversal to a CD4+ Th1-type of response upon genetic immunisation by the intramuscular route was not observed. Instead, vaccination with either the meta 1 gene alone or in fusion with the monocyte chemotactic protein (MCP)-3 cDNA induced a Th2-type of response that correlated with lack of protection against infection.