In vitro immunotoxicity effects of carbendazim were inhibited by n-acetylcysteine in microglial BV-2 cells.

Carbendazim (CBZ) is a benzimidazole fungicide widely used worldwide in industrial, agricultural, and veterinary practices. Although, CBZ was found in all brain tissues causing serious neurotoxicity, its impact on brain immune cells remain scarcely understood. Our study investigated the in vitro effects of CBZ on activated microglial BV-2 cells. Lipopolysaccharide (LPS)-stimulated BV-2 cells were exposed to increasing concentrations of CBZ and cytokine release was measured by ELISA, and Cytometric Bead Array (CBA) assays. Mitochondrial superoxide anion (O2·-) generation was evaluated by Dihydroethidium (DHE) and nitric oxide (NO) was assessed by Griess reagent. Lipid peroxidation was evaluated by measuring the malonaldehyde (MDA) levels. The transmembrane mitochondrial potential (ΔΨm) was detected by cytometry analysis with dihexyloxacarbocyanine iodide (DiOC6(3)) assay. CBZ concentration-dependently increased IL-1ß, IL-6, TNF-α and MCP-1 by LPS-activated BV-2 cells. CBZ significantly promoted oxidative stress by increasing NO, O2·- generation, and MDA levels. In contrast, CBZ significantly decreased ΔΨm. Pre-treatment of BV-2 cells with N-acetylcysteine (NAC) reversed all the above mentioned immunotoxic parameters, suggesting a potential protective role of NAC against CBZ-induced immunotoxicity via its antioxidant and anti-inflammatory effects on activated BV-2 cells. Therefore, microglial proinflammatory over-activation by CBZ may be a potential mechanism by which CBZ could induce neurotoxicity and neurodegenerative disorders.

In Vitro Effects of Cypermethrin and Glyphosate on LPS-Induced Immune Cell Activation.

(1) Background: The insecticide cypermethrin (Cypm) and the herbicide glyphosate (Glyp) are among the most widely used pesticides. While the two pesticides have been considered to have low toxicity in mammals, some indication of potential immunotoxicity has emerged. The aim of this work was to investigate in vitro the effects of Cypm and Glyp on bacteria lipopolysaccharide (LPS)-induced immune cell activation and of Cypm on 2-mercaptobenzothiazole (MBT)-induced maturation of dendritic cells (DCs). (2) Methods: The release of the inflammatory cytokines TNF-α and IL-8, the expression of the surface markers CD54 and CD86 in human primary peripheral blood mononuclear cells (PBMC), and THP-1 cells were investigated together with CD83, HLA-DR, IL-6, and IL-18 in DCs. (3) Results: While no significant modulation on LPS-induced immune cell activation was observed following Glyp exposure, with only a trend toward an increase at the highest concentration tested, Cypm reduced the responses to LPS and to MBT, supporting a direct immunosuppressive effect. Overall, the present study contributes to our understanding of pesticide-induced immunotoxicity, and the results obtained support evidence showing the immunosuppressive effects of Cypm.

Human glutathione peroxidase codon 198 variant increases nasopharyngeal carcinoma risk and progression.

PURPOSE: Glutathione peroxidase 1 (GPx-1) is a selenium-dependent detoxifying enzyme involved in the protection of cells against oxidative damage. Some genetic association studies reported significant associations between GPx-1 Pro198Leu variant and carcinogenesis across different populations; however, the impact of this variant on nasopharyngeal carcinoma (NPC) has not been explored. Therefore, the present study was planned to evaluate the potential involvement of the GPx-1 Pro198Leu variant and plasma GPx activity in the risk of developing NPC in a Tunisian population. METHODS: The GPx-1 Pro198Leu genotype was determined in 327 NPC patients and 150 healthy controls by the RFLP-PCR analysis. The correlation between the GPx-1 variant and the clinicopathological parameters was examined. GPx activity was assessed in the plasma of 119 NPC patients and 58 healthy control subjects and according to GPx-1 genotypes and clinicopathological characteristics of NPC patients. RESULTS: A significant association was found between GPx-1 Pro198Leu variant and NPC risk in a Tunisian population. The allelic frequencies of Pro and Leu alleles were 32% versus 68% and 41% versus 59% in NPC cases and controls, respectively. Thus, the minor 198 Leu allele increased significantly in NPC patients and appeared as a potential risk factor for NPC occurrence (OR = 1.48, CI 95% = 1.14-1.91, p = 0.002). The plasma GPx activity was significantly higher in NPC patients than in controls (p = 0.03). According to the clinicopathological characteristics of NPC patients, GPx activity decreased significantly in patients with lymph node metastasis (p = 0.004). CONCLUSION: This is the first study showing a strong association between GPx-1 Pro198Leu genetic variant and NPC risk. GPx-1 Pro198Leu variant increased the development of regional lymph node metastasis. Plasma GPx activity was higher in NPC patients. Thus, GPx-1 gene could be considered as a determinant factor influencing NPC risk and progression.

N-acetylcysteine reduced the immunotoxicity effects induced in vitro by azoxystrobin and iprodione fungicides in mice.

Azoxystrobin (AZO) and Iprodione (IPR) fungicides are extensively used worldwide, and therefore, contaminate all environmental compartments. The toxicity and the mechanisms by which they affected immune cells are complex and remain unknown. This study investigated the impact of AZO and IPR on the in vitro function of mice peritoneal macrophages including lysosomal enzyme activity and tumor necrosis factor (TNF)α and nitric oxide (NO) production in response to lipopolysaccharide (LPS) stimulation, the proliferation of mice splenocytes stimulated by concanavalin (Con)A and LPS, and the production of the Th1cytokine interferon-gamma (IFNγ) and the Th2 cytokine interleukin (IL)-4 and IL-10 by ConA-activated splenocytes. This is the first report indicating that AZO and IPR fungicides dose-dependently inhibited mice macrophage lysosomal enzyme activity and LPS-stimulated production of TNFα and NO. Mitogen-induced proliferation of mice splenocytes was also suppressed by AZO and IPR in a dose-dependent manner. More pronounced impact was observed on ConA-induced response. The production of IFNγ by ConA-stimulated splenocytes was dose-dependently inhibited; however, the production of IL-4 and IL-10 increased in the same conditions. These results suggested that AZO and IPR polarized Th1/Th2 cytokine balance towards Th2 response. Overall, marked immunosuppressive effects were observed for AZO. The immunomodulatory effects caused by AZO and IPR were partially reversed by the pharmacological antioxidant N-acetylcysteine (NAC), suggesting that both fungicides exerted their actions through, at least in part, oxidative stress-dependent mechanism. Collectively, our data showed that AZO and IPR fungicides exerted potent immunomodulatory effects in vitro with eventually strong consequences on immune response and immunologically based diseases.

Contribution of Nitric oxide synthase 3 genetic variants to nasopharyngeal carcinoma risk and progression in a Tunisian population.

PURPOSE: We conduct this study to evaluate the clinical and functional impact of Nitric Oxide Synthase 3 (NOS3) T-786C and G894T genetic variants on nasopharyngeal carcinoma (NPC) risk and progression in a Tunisian population. METHODS: 259 NPC patients and 169 healthy controls were enrolled into our case-control study. Blood samples were genotyped by the RFLP-PCR analysis. The levels of Nitric oxide (NO) were measured by a colorimetric assay kit in the plasma of NPC patients, healthy controls and according to NOS3 genotypes. The correlation between the NOS3 variants and the clinicopathological parameters was examined. RESULTS: We found no linkage disequilibrium between NOS3 T-786C and G894T variants. These results showed that NOS3 variants were genetically independent. In contrast to NOS3 T-786C, a significant association was found between NOS3 G894T polymorphism and NPC risk. The 894T allele decreased significantly in NPC patients and appeared as protective factor (OR = 0.65, CI 95%= 0.48-0.88, p = 0.006). NPC patients had significantly higher levels of plasma NO as compared to healthy controls (p = 0.0011). The T-786C mutation reduced the levels of plasma NO and decreased risk of lymph node metastasis in NPC patients (OR = 0.64, 95% CI = 0.43-0.96; p = 0.03). In contrast, NOS3 G894T polymorphism had no effects neither on NO plasma levels nor clinical parameters. CONCLUSIONS: This is the first study to associate NPC with significantly higher levels of plasma NO. NOS3-derived NO could play key roles in NPC pathogenesis. NOS3 variants differently contribute to NPC risk and progression in a Tunisian population. NOS3 G894T was associated with NPC risk. NOS3 T-786C decreased the levels of plasma NO and reduced the development of regional lymph node metastasis.

Modulation of macrophage functionality induced in vitro by chlorpyrifos and carbendazim pesticides.

The immune response is the first defense against pathogens; however, it is very sensitive and can be impacted on by agrochemicals such as carbamate and organophosphate pesticides widely present in the environment. To understand how pesticides can affect immune cell function in vitro, this study investigated the effects of chlorpyrifos (CPF) and carbendazim (CBZ), the most commonly used pesticides worldwide, on murine immune cell (i.e. macrophage) functions, including lysosomal enzyme activity and pro-inflammatory cytokines (IL-1ß and TNFα) and nitric oxide (NO) production by isolated mouse peritoneal macrophages. This study showed for the first time that CPF and CBZ dose-relatedly reduced macrophage lysosomal enzyme activity and LPS-induced production of IL-1ß, TNFα and NO. In general, the effects caused by CPF appeared more pronounced than those by CBZ. Collectively, these results demonstrated that CPF and CBZ exhibited marked immunomodulatory effects and could act as potent immunosuppressive factors in vitro. This inhibition of macrophage pro-inflammatory function may be an integral part of the underlying mode of action related to pesticide-induced immunosuppression.

Epigenetic regulations of inflammatory cyclooxygenase-derived prostanoids: molecular basis and pathophysiological consequences.

The potential relevance of prostanoid signaling in immunity and immunological disorders, or disease susceptibility and individual variations in drug responses, is an important area for investigation. The deregulation of Cyclooxygenase- (COX-) derived prostanoids has been reported in several immunoinflammatory disorders such as asthma, rheumatoid arthritis, cancer, and autoimmune diseases. In addition to the environmental factors and the genetic background to diseases, epigenetic mechanisms involved in the fine regulation of prostanoid biosynthesis and/or receptor signaling appeared to be an additional level of complexity in the understanding of prostanoid biology and crucial in controlling the different components of the COX pathways. Epigenetic alterations targeting inflammatory components of prostanoid biosynthesis and signaling pathways may be important in the process of neoplasia, depending on the tissue microenvironment and target genes. Here, we focused on the epigenetic modifications of inflammatory prostanoids in physiological immune response and immunological disorders. We described how major prostanoids and their receptors can be functionally regulated epigenetically and consequently the impact of these processes in the pathogenesis inflammatory diseases and the development of therapeutic approaches that may have important clinical applications.

The immunobiology of prostanoid receptor signaling in connecting innate and adaptive immunity.

Prostanoids, including prostaglandins (PGs), thromboxanes (TXs), and prostacyclins, are synthesized from arachidonic acid (AA) by the action of Cyclooxygenase (COX) enzymes. They are bioactive inflammatory lipid mediators that play a key role in immunity and immunopathology. Prostanoids exert their effects on immune and inflammatory cells by binding to membrane receptors that are widely expressed throughout the immune system and act at multiple levels in innate and adaptive immunity. The immunoregulatory role of prostanoids results from their ability to regulate cell-cell interaction, antigen presentation, cytokine production, cytokine receptor expression, differentiation, survival, apoptosis, cell-surface molecule levels, and cell migration in both autocrine and paracrine manners. By acting on immune cells of both systems, prostanoids and their receptors have great impact on immune regulation and play a pivotal role in connecting innate and adaptive immunity. This paper focuses on the immunobiology of prostanoid receptor signaling because of their potential clinical relevance for various disorders including inflammation, autoimmunity, and tumorigenesis. We mainly discuss the effects of major COX metabolites, PGD2, PGE2, their signaling during dendritic cell (DC)-natural killer (NK) reciprocal crosstalk, DC-T cell interaction, and subsequent consequences on determining crucial aspects of innate and adaptive immunity in normal and pathological settings.

Reciprocal crosstalk between dendritic cells and natural killer cells under the effects of PGE2 in immunity and immunopathology.

The reciprocal activating crosstalk between dendritic cells (DCs) and natural killer (NK) cells plays a pivotal role in regulating immune defense against viruses and tumors. The cytokine-producing capacity, Th-cell polarizing ability and chemokine expression, migration and stimulatory functions of DCs are regulated by activated NK cells. Conversely, the innate and effector functions of NK cells require close interactions with activated DCs. Cell membrane-associated molecules and soluble mediators, including cytokines and prostaglandins (PGs), contribute to the bidirectional crosstalk between DCs and NK cells. One of the most well-known and well-studied PGs is PGE2. Produced by many cell types, PGE2 has been shown to affect various aspects of the immune and inflammatory responses by acting on all components of the immune system. There is emerging evidence that PGE2 plays crucial roles in DC and NK cell biology. Several studies have shown that DCs are not only a source of PGE2, but also a target of its immunomodulatory action in normal immune response and during immune disorders. Although NK cells appear to be unable to produce PGE2, they are described as powerful PGE2-responding cells, as they express all PGE2 E-prostanoid (EP) receptors. Several NK cell functions (lysis, migration, proliferation, cytokine production) are influenced by PGE2. This review highlights the effects of PGE2 on DC-NK cell crosstalk and its subsequent impact on immune regulations in normal and immunopathological processes.

Age- and gender-specific effects on NRAMP1 gene polymorphisms and risk of the development of active tuberculosis in Tunisian populations.

BACKGROUND: Studies that have assessed NRAMP1 polymorphisms and their association with susceptibility to tuberculosis (TB) in humans have yielded conflicting results. In this study, we evaluated the association between NRAMP1 gene polymorphisms and the risk of the development of active TB in Tunisian populations. METHODS: The distribution of 3'-UTR and D543N polymorphisms in 223 TB patients (168 patients with pulmonary TB (PTB) and 55 patients with extrapulmonary TB (EPTB)) and 150 healthy donors was determined by PCR-restriction fragment length polymorphism (RFLP) method. RESULTS: We found that AA and AG genotypes appeared to be associated with susceptibility to PTB (odds ratio (OR) 10.8, 95% confidence interval (CI) 1.37-230.8; p corrected for the number of genotypes (pc)=0.018) and EPTB (OR 4.37, 95% CI 1.64-11.82; pc=0.0024), respectively, in patients aged less than 30 years. However, wild-type GG genotype appeared to be associated with resistance against PTB in females (OR 0.1, 95% CI 0.01-0.74; pc=0.03). The 3'-UTR del/del genotype appeared to be associated with susceptibility to PTB in patients aged less than 30 years (OR 3.75, 95% CI 1.5-9.52; pc=0.003). In contrast, TGTG+/del might be associated with resistance against the development of active PTB (OR 0.23, 95% CI 0.08-0.65; pc=0.003). A-del haplotype appeared to be associated with susceptibility to PTB (OR 1.79, 95% CI 1.11-2.9; pc=0.04). CONCLUSIONS: Collectively, our results suggest an association of NRAMP1 3'-UTR and D543N polymorphisms with susceptibility to mycobacterial infection in Tunisian populations in relation to age and sex.

IL-10R1 S138G loss-of-function polymorphism is associated with extrapulmonary tuberculosis risk development in Tunisia.

There is considerable evidence that host genetic factors are important in determining susceptibility to mycobacterial infections. More recently, functional genetic mutations affecting IL-10 receptor 1 (IL-10R1) were described. In this study, we investigated the relationship of IL-10R1 S138G loss-of-function polymorphism (A536G: rs3135932) with susceptibility to active tuberculosis (TB) in Tunisian patients. A total of 168 patients with pulmonary TB, 55 with extrapulmonary TB, and 150 control subjects were studied. Genomic DNA samples were extracted from leukocytes and used to investigate S138G polymorphism in IL-10R1 gene by multiplex allele-specific polymerase chain reaction. Associations between G allele [odds ratio OR=5.01; 95% confidence intervals CI=2.58-9.77; P=10(-7)], GG genotypes [OR=9.06; 95% CI (1.58-67.33); correcting P-values using the Bonferroni method for multiple tests Pc=0.015] and AG genotype [OR=3.75; 95% CI (1.62-8.7); Pc=0.0012] with the risk development of active extrapulmonary TB were found. In contrast, the AA genotype was found to be associated with resistance to extrapulmonary TB [OR=0.19; 95% CI (0.09-0.42); Pc=6.10(-6)]. No association was found between S138G SNP and pulmonary TB. In conclusion, our study suggested the possible role of IL-10R1 S138G loss-of-function polymorphism in extrapulmonary TB susceptibility-resistance in Tunisia.

Immunochromatographic IgG/IgM test for rapid diagnosis of active tuberculosis.

For rapid diagnosis and discrimination between active tuberculosis (TB) and other pulmonary diseases, we evaluated the clinical usefulness of detection of serum immunoglobulin IgG and IgM antibodies raised against mycobacterial 38-kDa, 16-kDa, and 6-kDa antigens by a commercial rapid immunochromatographic IgG/IgM test (Standard Diagnostics, South Korea) in 246 serum samples from three groups of patients: (i) 171 patients with active TB (128 with pulmonary TB [pTB] and 43 with extrapulmonary TB [epTB]), (ii) 73 patients with pulmonary non-TB diseases, and (iii) two leprosy patients. The sensitivities of IgG and IgM in patients with active TB (pTB and epTB) were 68.4% and 2.3%, respectively. IgG had the best performance characteristics, with sensitivities of 78.1% and 39.5% in sera from patients with active pTB and epTB, respectively, and a specificity of 100%. The sensitivities of IgM were poor and were similar for pTB and epTB (2.3%). In contrast, specificity was very elevated (100%). The combination of IgG with IgM did not improve its sensitivity. IgG-mediated responses against the mycobacterial 38-kDa, 16-kDa, and 6-kDa antigens might constitute a clinically useful tool for presumptive diagnosis and discrimination of active pTB from other pulmonary diseases. Moreover, based on its simplicity and rapidity of application, it could be a screening tool for active pTB in poorly equipped laboratories.

Contribution of the P2X7 1513A/C loss-of-function polymorphism to extrapulmonary tuberculosis susceptibility in Tunisian populations.

The P2X7 receptor has been found to be linked to an increased risk for tuberculosis in some populations. In this study, we investigate whether the P2X7 receptor plays a role in increasing susceptibility to tuberculosis in Tunisia. We examined two 1513A/C and -762T/C polymorphisms at the P2X7 receptor in 168 patients with pulmonary TB (pTB), 55 patients with extrapulmonary TB (epTB) and 150 blood donors from Tunisia. Genotyping of 1513A/C and -762T/C polymorphisms was performed in purified genomic DNA using PCR-restriction fragment length polymorphism and allele-specific PCR, respectively. The 1513C, CC and AC loss-of-function allele and genotypes were overrepresented in the epTB group compared with the control group (45% vs. 17%, P=10(-8) ; 24% vs. 4%, P=3 × 10(-7) ; 42% vs. 27%, P=10(-3) , respectively). Additionally, they were associated with 3.83-, 11.86- and 3.15-fold risks of developing this clinical tuberculosis form, respectively. No associations between the -762T/C polymorphism and tuberculosis disease, as well as disease anatomic location were observed. Collectively, our results suggest that the P2X7 1513A/C loss-of-function polymorphism may contribute to susceptibility to epTB in Tunisian populations.

Association of TNF-α and IL-10 polymorphisms with tuberculosis in Tunisian populations.

Cytokine Th1/Th2 balance is known to play a key role in controlling Mycobacterium tuberculosis infection. Based upon the functional role of the TNF-α [-308 G(low) â†’ A(high) (rs1800629)] and IL-10 [-1082 A(low) â†’ G(high) (rs1800870), -819 T(low) â†’ C(high) (rs1800871) and -592 A(low) â†’ C(high) (rs1800872)] single nucleotide polymorphisms (SNPs) on production levels, we genotyped 76 patients with pulmonary tuberculosis (TB) (pTB), 55 patients with extrapulmonary TB (epTB) and 95 healthy blood donors by polymerase chain reaction fragment length polymorphism (PCR-RFLP). We observed that -308 A allele was associated with increased risk susceptibility to epTB (OR = 1.96; 95% CI, 1.04-3.71; P = 0.024). The -1082 AG genotype was significantly associated with increased risk development of epTB (odds ratio [OR] = 3.69; 95% confidence intervals [CI], 1.73-7.92; P corrected for the number of genotypes [Pc] = 0.0003). By contrast, -1082 AA genotype appeared to be associated with resistance to pTB (OR = 0.38; 95% CI, 0.19-0.74; Pc = 0.006) and epTB (OR = 0.22; 95% CI, 0.1-0.48; Pc = 0.00006). High-producer IL-10 GCC haplotype seemed to be associated with 2.11-fold (95% CI, 1.28-3.46; Pc = 0.003) and 2.57-fold (95% CI, 1.5-4.4; Pc = 0.0006) increased susceptibility to pTB and epTB, respectively. Combination of TNF-α/IL-10 high producer genotypes was associated with increased 3.13-fold (95% CI, 1.23-8.05; Pc = 0.028) susceptibility to epTB. However, combined TNF-α/IL-10 low producer genotypes appeared to have protect effect to pTB (OR = 0.44, 95% CI, 0.21-0.89; Pc = 0.04) and epTB (OR = 0.26, 95% CI, 0.1-0.62; Pc = 0.0028). Collectively, our results showed that analysed SNPs in the TNF-α and IL-10 gene polymorphisms play key role in susceptibility to or protection against TB development in Tunisian populations.

Polymorphisms in the RANTES gene increase susceptibility to active tuberculosis in Tunisia.

RANTES plays a pivotal role in attracting and activating various leukocyte populations that control Mycobacterium tuberculosis infection. The present study investigated the relationship between the RANTES polymorphisms (-28C/G; rs2280788, and -403G/A; rs2107538) and susceptibility to active tuberculosis (TB) in Tunisian populations. A total of 168 patients with pulmonary TB (pTB), 55 with extrapulmonary TB (epTB), and 150 control subjects were studied. Genotype analyses were carried out using polymerase chain reaction-restriction fragment length polymorphism method. We found that the -28 GG genotype was significantly associated with susceptibility to pTB (odds ratio [OR]=11.19; 95% confidence intervals [CI], 5.14-25; P corrected for the number of genotypes [Pc]=10(-8)) and epTB (OR=11.67; 95% CI, 4.74-29.33; Pc=10(-8)). However, the -28 CC genotype was found to be significantly associated with resistance to pTB (OR=0.08; 95% CI, 0.04-0.16; Pc=10(-8)) and epTB development (OR=0.11; 95% CI, 0.05-0.27; Pc=10(-8)). -403A allele was associated with increased risk development of epTB (OR=2.21; 95% CI, 1.18-4.14; p=0.007). G-G and A-C haplotypes and the AG/GC diplotype were associated with increase susceptibility to pTB (OR=7.88, 95% CI, 5.38-11.55; Pc=3.10(-8); OR=2.32, 95% CI, 1.32-4.11; Pc=3.10(-3); OR=13.26, 95% CI, 6.06-29.89; Pc=3.10(-8); respectively) and epTB (OR=6.64, 95% CI, 4-11.05; Pc=3.10(-8); OR=2.6, 95% CI, 1.26-5.35; Pc=12.10(-3); OR=11.26, 95% CI, 4.44-29.28; Pc=3.10(-8); respectively). Collectively, our findings suggested an association of the RANTES -28C/G and -403G/A functional polymorphisms with susceptibility to Mycobacterium tuberculosis infection in Tunisian populations.

MCP-1 -2518 A/G functional polymorphism is associated with increased susceptibility to active pulmonary tuberculosis in Tunisian patients.

Monocyte chemoattractant protein-1 (MCP-1) plays crucial role in protective immunity against Mycobacterium tuberculosis (MT). In this study, we examined whether single nucleotide polymorphism (SNP) -2518 A/G (rs 1024611) of MCP-1 affect the susceptibility to active tuberculosis (TB) in Tunisian populations. Genomic DNA from patients with active TB (168 cases of pulmonary TB and 55 cases of extrapulmonary TB) and ethnically controls (150 cases) was genotyped for the MCP-1 -2518 A/G SNP by polymerase chain reaction fragment length polymorphism (PCR-RFLP). We observed that -2518 G allele and GG genotype (high MCP-1 producer) frequencies were significantly more elevated in active pulmonary TB group in comparison to control group [34 vs. 22%; P = 0.0007; 15 vs. 5%, P corrected for the number of genotypes (Pc) = 0.015; respectively]. Additionally, they were associated with increased risk development of this clinical form of TB [odds ratio (OR) = 1.83, 95% confidence intervals (CI) = 1.26-2.66; OR = 3.1, 95% CI = 1.28-7.76; respectively]. However, wild type allele -2518 A and AA genotype were over-represented in control group (78 and 62%) and seem to be protective factors against TB. Moreover, -2518 AA genotype was more frequent in control group and was associated with resistance against development of active pulmonary TB (OR = 0.56, 95% CI = 0.35-0.89, Pc = 0.03). Our findings confirm the key role of -2518 A/G SNP of MCP-1 and support its association with resistance/susceptibility to the development of active pulmonary TB in the Tunisian population.

Anti-inflammatory and antiulcerogenic activities of leaf extracts and sesquiterpene from Teucrium ramosissimum (Lamiaceae).

Teucrium ramosissimum (Lamiaceae) is a native and endemic medicinal plant from South of Tunisia traditionally used for the treatment of many diseases. The anti-inflammatory and antiulcerogenic activities of sesquiterpene (ß-eudesmol), chloroform, and ethyl acetate leaf extracts from T. ramosissimum were assayed. Macrophage phagocytic activity and lymphocyte proliferation in the absence and presence of mitogens (lipopolysaccharide [LPS] or lectin) were investigated. Depending on the concentrations, the extracts affect macrophage functions by modulating their lysosomal enzyme activity and nitric oxide (NO) release. For lymphocyte proliferation assay, tested extracts enhance significantly cell proliferation either with or without mitogen stimulation. These results suggest that leaf extracts from T. ramosissimum contain potent components such as flavonoids that may be potentially useful for modulating immune cell functions in physiological and pathological conditions. Antiulcerogenic activity was examined on rat ethanol-induced ulcerogenic model. Compared with control (cimetidine), leaf extracts from T. ramosissimum exert different protective effects against ethanol-induced ulcerogenesis.

Interferon gamma +874T/A polymorphism is associated with susceptibility to active pulmonary tuberculosis development in Tunisian patients.

Interferon gamma (IFN-γ) is a key cytokine involved mainly in the defense against intracellular pathogens such as Mycobacterium tuberculosis. Given its key role in the control of tuberculosis (TB), in the present article we have investigated a possible association between IFN-γ gene single-nucleotide polymorphism linked to high and low producer phenotypes (IFN-γ [+874T(high) → A(low)]) (rs2430561) and risk development of active TB in Tunisian patients. Genomic DNA samples were obtained from 223 patients with active TB (168 pulmonary and 55 extrapulmonary cases) and 150 healthy blood donors. Genotypes were analyzed using polymerase chain reaction-restriction fragment length polymorphism method. The +874 AA genotype (low IFN-γ producer) was significantly associated with increased risk of developing of active pulmonary TB (odds ratio [OR] = 2.18; 95% confidence intervals [CI], 1.33-3.57; P corrected for the number of genotypes [Pc] = 0.003). By contrast, the AT genotype was found to be significantly associated with resistance to pulmonary TB (OR = 0.46; 95% CI, 0.28-0.74; Pc = 0.0018) and extrapulmonary TB development (OR = 0.46; 95% CI, 0.23-0.91; Pc = 0.045). Collectively, our data showed that the IFN-γ +874T/A polymorphism is a determinant in the resistance or susceptibility to the development of active TB in the studied population.

CD40 engagement on dendritic cells induces cyclooxygenase-2 and EP2 receptor via p38 and ERK MAPKs.

We have previously reported that cyclooxygenase (COX)-2-derived prostaglandin (PG)E2 critically regulates dendritic cell (DC) inflammatory phenotype and function through EP2/EP4 receptor subtypes. As genes activated by CD40 engagement are directly relevant to inflammation, we examined the effects of CD40 activation on inflammatory PGs in murine bone marrow-derived DC (mBM-DC). We showed for the first time that activation of mBM-DC with agonist anti-CD40 monoclonal antibody (anti-CD40 mAb) dose dependently induces the synthesis of significant amounts of PGE2 via inducible expression of COX-2 enzyme, as NS-398, a COX-2-selective inhibitor reduces this upregulation. In contrast to lipopolysaccharide, which upregulates mBM-DC surface levels of EP2 and EP4 receptors, CD40 crosslinking on mBM-DC increases EP2, but not EP4, receptor expression. Flow cytometry analysis and radioligand-binding assay showed that EP2 was the major EP receptor subtype, which binds to PGE2 at the surface of anti-CD40-activated mBM-DC. Upregulation of COX-2 and EP2 levels by CD40 engagement was accompanied by dose-dependent phosphorylation of p38 and ERK1/2 mitogen-activated protein kinase (MAPK) and was abrogated by inhibitors of both pathways. Collectively, we demonstrated that CD40 engagement on mBM-DC upregulates COX-2 and EP2 receptor expression through activation of p38 and ERK1/2 MAPK signaling. Triggering the PGE2/EP2 pathway by anti-CD40 mAb resulted on the induction of Th2 immune response. Thus, CD40-induced production of PGE2 by mBM-DC could represent a negative feedback mechanism involving EP2 receptor and limiting the propagation of Th1 responses. Blocking CD40 pathway may represent a novel therapeutic pathway of inhibiting COX-2-derived prostanoids in chronically inflamed tissues (that is, arthritis).

Inhibition of proinflammatory macrophage responses and lymphocyte proliferation in vitro by ethyl acetate leaf extract from Daphne gnidium.

Medicinal plants are considered immunomodulatory as they display various biological activities. There is no report addressing the anti-inflammatory effects of Daphne gnidium. In this study, we investigated the effects of D. gnidium ethyl acetate (EA) leaf extract on mice immune cell function in vitro. Production of pro-inflammatory cytokines (IL-1ß and TNF-α), cyclooxygenase-2-derived prostaglandinE2 (PGE2) and iNOS-II-synthesised nitric oxide (NO) were examined. EA extract effect on mitogen-induced lymphocyte proliferation was also investigated. We reported for the first time that D. gnidium EA leaf extract dose-dependently inhibits macrophage proinflammatory function by reducing LPS-induced production of IL-1ß, TNF-α, COX-2-derived PGE2 and iNOS-II-synthesised NO. Mitogen-induced lymphocyte proliferation was also dose-dependently inhibited by the extract. Lectin-induced response appears to be more sensitive to the suppressive effects of the extract than LPS-stimulated response. Collectively, these results demonstrate that D. gnidium EA leaf extract acts as an in vitro anti-inflammatory factor by inhibiting mice macrophage and lymphocyte activities.