Helminth species dependent effects on Th1 and Th17 cytokines in active tuberculosis patients and healthy community controls

Despite that the impact of different helminth species is not well explored, the current dogma states that helminths affect the Th1/Th2 balance which in turn affects the risk of tuberculosis (TB) reactivation and severity of disease. We investigated the influence of helminth species on cytokine profiles including IL-17A in TB patients and healthy community controls (CCs). In total, 104 newly diagnosed pulmonary TB patients and 70 HIV negative and QuantiFERON negative CCs in Gondar, Ethiopia were included following helminth screening by stool microscopy. Plasma samples and ex vivo stimulation of peripheral blood mononuclear cells (PBMCs) with purified protein derivative (PPD) and Staphylococcus enterotoxin B (SEB) was used to determine cytokine profiles by cytometric bead array. In CCs, Ascaris lumbricoides or Schistosoma mansoni infections were associated with an impaired Th1-type response (IFN-gamma, IL-6 and TNF-alpha) in PBMCs mainly with SEB stimulations, whereas in TB patients only hookworm infection showed a similar pattern. Among CCs, the IL-17A response in PBMCs stimulated with SEB was higher only for S. mansoni, whereas in TB patients, the elevated systemic IL-17A plasma level was significantly suppressed in hookworm infected TB patients compared to patients without helminth coinfection. Following treatment of TB and helminth infection there was a general decrease in ex vivio IL-10 and TNF-alpha production in unstimulated, PPD or SEB stimulated PBMCs that was the most pronounced and significant in TB patients infected with S. mansoni, whereas the follow-up levels of IFN-gamma and IL-17A was significantly increased only in TB patients without helminth coinfection from PBMCs stimulated mainly with SEB. In summary, in addition to confirming helminth specific effects on the Th1/Th2 response before and after TB treatment, our novel finding is that IL-17A was impaired in helminth infected TB patients especially for hookworm, indicating a helminth species-specific immunoregulatory effect on IL-17A which needs to be further investigated.     

Suppression of Mycobacterium tuberculosis induced reactive oxygen species (ROS) and TNF-alpha mRNA expression in human monocytes by allicin

Chronic inflammation associated with tumor necrosis factor (TNF)-alpha and reactive oxygen species (ROS) is the hallmark of tuberculosis. Mycobacterium tuberculosis (MTB) directly stimulates human monocytes to secrete TNF-alpha. We show the augmented expression of TNF-alpha mRNA in MTB-infected monocytes by cellular activation and ROS was suppressed by allicin in a dose-dependent manner. Also, allicin enhanced the glutathione peroxidase activity, which correlated inversely with the downregulation of ROS and TNF-alpha in MTB-infected monocytes. Hence, allicin may prove to be a valuable natural antioxidant in combating tuberculosis.     

HIV-1 Tat induces TNF-alpha production by human monocytes: involvement of calcium and PKC pathways

In this study we investigated the signaling pathways triggered by Tat in human monocyte to induce TNF-alpha. In monocytes, calcium, PKA, and PKC pathways are highly implicated in the expression of cytokine genes. Our data show that (i) extracellular calcium is required for the calcium signal initiated by Tat in the monocyte and is required for TNF-alpha production, PKC pathway is also required, whereas the PKA pathway does not seem to be involved (ii) downstream from PKC, activation of NF kappa B is essential while ERK1/2 MAP kinases, even though activated by Tat, are not directly involved in the pathway signaling leading to TNF-alpha production.     

Inhibition of Rho family GTPases results in increased TNF-alpha production after lipopolysaccharide exposure

These studies demonstrate that treatment of macrophages with lovastatin, a cholesterol-lowering drug that blocks farnesylation and geranylgeranylation of target proteins, increases LPS-induced TNF-alpha production. This is reversed by the addition of mevalonate, which bypasses the lovastatin block. Examination of membrane localization of RhoA, Cdc42, Rac1, and Ras demonstrated decreased membrane localization of the geranylgeranylated Rho family members (RhoA, Cdc42, and Rac1) with no change in the membrane localization of farnesylated Ras. LPS-induced TNF-alpha production in the presence of the Rho family-specific blocker (toxin B from Clostridium difficile) was significantly enhanced consistent with the lovastatin data. One intracellular signaling pathway that is required for TNF-alpha production by LPS is the extracellular signal-regulated kinase (ERK). Significantly, we found prolonged ERK activation after LPS stimulation of lovastatin-treated macrophages. When we inhibited ERK, we blocked the lovastatin-induced increase in TNF-alpha production. As a composite, these studies demonstrate a negative role for one or more Rho family GTPases in LPS-induced TNF-alpha production.     

Differential regulation of TNF-alpha and IL-1beta production from endotoxin stimulated human monocytes by phosphodiesterase inhibitors

The effect of selective PDE-I (vinpocetine), PDE-III (milrinone, CI-930), PDE-IV (rolipram, nitroquazone), and PDE-V (zaprinast) isozyme inhibitors on TNF-alpha and IL-1beta production from LPS stimulated human monocytes was investigated. The PDE-IV inhibitors caused a concentration dependent inhibition of TNF-alpha production, but only partially inhibited IL-1beta at high concentrations. High concentrations of the PDE-III inhibitors weakly inhibited TNF-alpha, but had no effect on IL-1beta production. PDE-V inhibition was associated with an augmentation of cytokine secretion. Studies with combinations of PDE isozyme inhibitors indicated that PDE-III and PDE-V inhibitors modulate rolipram's suppression of TNF production in an additive manner. These data confirm that TNF-alpha and IL-1beta production from LPS stimulated human monocytes are differentially regulated, and suggest that PDE-IV inhibitors have the potential to suppress TNF levels in man.     

Immunomodulatory effects of glycine on LPS-treated monocytes: reduced TNF-alpha production and accelerated IL-10 expression.

Cytokines play a pivotal role in the pathogenesis of septic shock. Proinflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) stimulate the progression of septic shock whereas the anti-inflammatory cytokine IL-10 has counterregulative potency. The amino acid glycine (GLY) has been shown to protect against endotoxin shock in the rat by inhibiting TNF-alpha production. In the current study we investigated the role of GLY on lipopolysaccharide (LPS) -induced cell surface marker expression, phagocytosis, and cytokine production on purified monocytes from healthy donors. GLY did not modulate the expression of HLA-DR and CD64 on monocytes, whereas CD11b/CD18 expression (P<0.05) and E. coli phagocytosis (P<0.05) decreased significantly. GLY decreased LPS-induced TNF-alpha production (P<0.01) and increased IL-10 expression of purified monocytes. Similarly, in a whole blood assay, GLY reduced TNF-alpha (P<0.0001) and IL-1beta (P<0.0001) synthesis and increased IL-10 expression (P<0.05) in a dose-dependent manner. The inhibitory effects of GLY were neutralized by strychnine, and the production of IL-10 and TNF-alpha was augmented by anti-IL-10 antibodies. Furthermore, GLY decreased the amount of IL-1beta and TNF-alpha-specific mRNA. Our data indicate that GLY has a potential to be used as an additional immunomodulatory tool in the early phase of sepsis and in different pathophysiological situations related to hypoxia and reperfusion.     

Prolonged production of TNF-alpha exacerbates illness during respiratory syncytial virus infection

CD8(+) CTL are the main effector cells responsible for resolving viral infections. However, the CTL response to respiratory syncytial virus (RSV) infection in mice facilitates viral clearance at the expense of significant immunopathology. Previous reports have shown a strong correlation between the mechanism of CTL activity and the severity of RSV-induced illness. Furthermore, experiments in perforin knockout mice revealed that antiviral cytokine production temporally correlated with RSV-induced illness. In the current study, we show that TNF-alpha is the dominant mediator of RSV-associated illness, and it is also important for clearance of virus-infected cells during the early stages of infection. We also demonstrate that IFN-gamma plays a protective role in conjunction with perforin/granzyme-mediated killing. Preliminary experiments in gld mice that express nonfunctional Fas ligand (FasL) revealed that RSV-induced illness is significantly reduced in the absence of FasL-mediated killing. Antiviral cytokine production was not elevated in the absence of FasL, suggesting a possible link between FasL and antiviral cytokine activity. This work shows that multiple phenotypic subsets of CD8(+) CTLs respond to RSV infection, each with varying capacities for clearance of virus-infected cells and the induction of illness. In addition, the revelation that TNF-alpha is the principal mediator of RSV-induced illness means that administration of TNF receptor antagonists, in combination with antiviral therapy, may be an effective method to treat RSV infections.     

Geographical expansion and increased prevalence of common species in avian assemblages: implications for large-scale patterns of species richness

Aim The assumption that ecological patterns at large spatial scales originate exclusively from non‐anthropogenic processes is growing more questionable with the increasing domination of the biosphere by humans. Because common and rare species are known to respond differently to anthropogenic activities at local scales these differential responses could, over time, be reflected in distributional patterns of species richness at larger spatial scales. This work tests the hypothesis that modern processes have played a role in shaping these patterns, by examining recent changes in the structure and composition of assemblages of breeding avifauna over a large geographical extent. Location The portion of North America containing the contiguous United States and southern Canada. Methods Changes in the geographical range structure of breeding avifauna in North America from 1968 to 2003 were analysed in regions containing historically moderate levels of anthropogenic activities. Two geographical measures, extent of occurrence and area of occupancy, were used to identify the level of rarity or commonality of individual species and to estimate, based on a vector analysis, patterns of change in geographical range structure for individual species and avian assemblages. Results More species experienced patterns of geographical range expansion (51%) than contraction (28%). The majority of avian assemblages (43%) displayed patterns of geographical range expansion: common species increased in number and proportion (6%) in association with reciprocal losses in rare and moderately rare species, resulting in a constant level of species richness. The minority of avian assemblages (21%) displayed patterns of geographical range contraction: gains occurred for common species as well as for rare and moderately rare species, resulting in substantial increases in species richness and a decline in the proportion of common species (4%). The remaining avian assemblages presented equivocal patterns characterized by gains in the number and proportion (2%) of common species and gains in species richness. Main conclusions Modern processes have played a role in shaping the distribution patterns of species richness at large spatial scales based on the composition of common and rare species. This suggests that anthropogenic activities cannot be ignored as a possible causal factor when considering ecological patterns at large spatial scales.     

Plasminogen-induced IL-1beta and TNF-alpha production in microglia is regulated by reactive oxygen species

Microglia, major immune effector cells in the central nervous system, become activated during brain injury. In this study we showed that the blood component plasminogen/plasmin activates microglia. Plasminogen-induced IL-1beta, TNF-alpha, and iNOS mRNA expression in primary cultured rat microglia and BV2 murine microglial cells. Plasmin caused a similar response. Serine protease inhibitors suppressed both plasminogen- and plasmin-induced IL-1beta and TNF-alpha expression, indicating the importance of serine protease activity in plasminogen/plasmin activation of microglia. Reactive oxygen species (ROS) appeared to play an important role in plasminogen-induced microglial activation, with ROS being generated within 15min of plasminogen treatment, and antioxidants (100 microM trolox and 10mM NAC) reducing IL-1beta and TNF-alpha expression in plasminogen-treated cells. Furthermore, plasminogen stimulated CREB and NF-kappaB DNA binding activity, and this activation was also reduced by trolox and NAC. These results suggest that plasminogen activates microglia via stimulation of ROS production.     

IFNgamma enhances IL-23 production during Francisella infection of human monocytes

We previously demonstrated that monocytes produce IL-23 during Francisella infection, and that IL-23 induces IFNgamma from NK cells. Here, we demonstrate that IFNgamma-priming of monocytes enhances IL-23 production during Francisella infection. This effect was seen on the IL12/23 p40 subunit. Induction of IL-12/23 p40 is reported to be enhanced by IRF-1 and IRF-8. Consistently, microarray analysis of IFNgamma-treated monocytes revealed a significant induction of the IRFs. Interestingly, IFNgamma-primed monocytes produced IL-12 p70, a more potent inducer of IFNgamma than IL-23. We propose that there exists an amplification loop between monocyte IL-23 and NK/T cell IFNgamma that leads to IL-12 p70 production.     

Endocytosis of heparin-binding protein (CAP37) is essential for the enhancement of lipopolysaccharide-induced TNF-alpha production in human monocytes

Heparin-binding protein (HBP), also known as CAP37, is a proteolytically inactive serine protease homologue that is released from activated granulocytes. However, HBP is not a biologically inactive molecule but rather a multifunctional protein with properties that include the enhancement of LPS-induced TNF-alpha production from monocytes. We have previously demonstrated that HBP is internalized in monocytes. In the current study, we hypothesize that HBP is internalized in monocytes via endocytosis, and this internalization is an important mechanism by which HBP enhances LPS-induced TNF-alpha release. Using whole blood from healthy donors and flow cytometry, we found that colchicine (0.1-10 mM), cytochalasin D (1000 microM), NH4Cl (10-50 mM), and bafilomycin A1 (0.1-3 microM) significantly reduced the affinity of FITC-HBP for CD14-positive monocytes. Using isolated human monocytes and ELISA, we found that colchicine (0.1 mM), cytochalasin D (30 and 300 microM), NH4Cl (30 mM), and bafilomycin A1 (1 microM) significantly reduced the effect of HBP (10 microg/ml) to enhance LPS (10 ng/ml)-induced TNF-alpha release after 24 h. These findings demonstrate that internalization of HBP in monocytes is essential for the enhancement of LPS-induced TNF-alpha release. Transport of HBP to an activating compartment depends on intact F-actin polymerization and endosomal acidification, an important mechanism for endosomal protein sorting and trafficking.     

Diagnosis of active tuberculosis using MPB64, a specific antigen of Mycobacterium bovis

Because the incidence of tuberculosis (TB) is still high in developing countries, an inexpensive and rapid diagnostic test for this infection is needed. To develop a screening test for TB, MPB64 antigen was produced by recombinant technology and purified with a polyhistidine tag. Next, serum and urine samples from patients with TB and uninfected individuals were examined by the dot‐blot assay method using this purified antigen. Serum samples from patients with TB reacted more strongly with MPB64 antigen than did those from uninfected individuals. In addition, serum samples from TB patients with active infection reacted more strongly with the antigen than did samples from patients with inactive TB. When urine samples were assessed using this assay, similar results were obtained. Correlations between the data obtained from serum and urine samples were analyzed for all subjects, including uninfected individuals, and a strong positive correlation between the results of serum and urine tests (n = 36, r = 0.672) was found. The sensitivity and specificity of this assay for serum samples was 85.7 % and 85.0 %, and for urine samples 75.0 % and 85.0 %, respectively. These results suggest that dot‐blot assay with MPB64 antigen could be a useful screening test for active TB. Because urine samples can be obtained more easily than serum samples and because urine is less contagious, urine testing should probably be employed for screening purposes.     

Wild birds in YouTube videos: Presence of specific species contributes to increased views

Recent advances in understanding cultural ecosystem services (CES) using big data such as social media and other web archives have been primarily made to identify the relationships between the specific indicators for CES and large-scale features of ecosystems, such as vegetation covers and types, ecosystem types, naturalness, and the proportion of areas designated as protected areas. Yet, we know little about how biodiversity and specific species contribute to the enhancement of CES. Here, we examined the factors influencing the number of views in YouTube videos displaying wild birds in nature as a direct indicator of CES related to aesthetic enjoyment, environmental education, and nature experience. We found that the presence of specific wild bird species (i.e., Streptopelia orientalis and Larvivora cyane) increased the number of views while controlling for confounding factors such as the length of the video and the number of days since uploading. We suggest that these species are widely recognized, positively perceived presumably owing to their cultural significance, and preferred among viewers watching videos of wild birds, resulting in more views for videos including these species. Finally, we depicted the geographic distribution (on a national scale) of YouTube videos displaying wild birds in nature. Urban and agricultural land cover around the geotagged location of each video negatively affected the number of views, suggesting that over-exploitation of ecosystems may lead to the loss of important CES. Our study thus demonstrates the contributions of specific wild bird species to enhancing the CES related to aesthetic enjoyment, environmental education, and nature experience, provided through online shared videos.     

IFN-beta inhibits the ability of T lymphocytes to induce TNF-alpha and IL-1beta production in monocytes upon direct cell-cell contact.

Tumour necrosis factor (TNF)-alpha and interleukin (IL-)1beta, essential players in the pathogenesis of immuno-inflammatory diseases, are strongly induced in monocytes by direct contact with stimulated T lymphocytes. The present study shows that the latter mechanism is inhibited by interferon (IFN)-beta. In co-cultures of autologous T lymphocytes and monocytes stimulated by phytohaemagglutinin (PHA), IFN-beta inhibited the production of TNF-alpha and IL-1beta by 88 and 98%, respectively, whereas the simultaneous production of IL-1 receptor antagonist (IL-1Ra), was enhanced two-fold. The latter effects of IFN-beta were independent of modulations in IFN-gamma, IL-4 and IL-10 production. When monocytes were activated by plasma membranes of stimulated T cells, IFN-beta slightly inhibited the production of TNF-alpha and IL-1beta, while enhancing 1.5-fold that of IL-1Ra. The latter effect correlated with the persistence of high steady-state levels of IL-1Ra mRNA after 24 h of activation. Membranes isolated from T lymphocytes that had been stimulated in the presence of IFN-beta displayed a 80% decrease in their capacity to induce the production of IL-1beta and TNF-alpha in monocytes, whereas IL-1Ra induction was decreased by only 32%. These results demonstrate that IFN-beta modulates contact-mediated activation of monocytes by acting on both T lymphocytes and monocytes, decreasing the ability of T lymphocytes to induce TNF-alpha and IL-1beta production in monocytes and directly enhancing the production of IL-1Ra in the latter cells.     

Characteristics of the production of active oxygen species from adherent and non-adherent neutrophils

Our objective was to evaluate the characteristics of the production of AOS from the neutrophils that had adhered to the endothelial cells, fibronectin or polystyrene, using the method of electron paramagnetic resonance (EPR) spin trapping. Neutrophils and endothelial cells were isolated from human venous blood and umbilical veins, respectively. AOS production from neutrophils was not elicited only by adhesion. The stimulation of adherent neutrophils with phorbol myristate acetate (PMA) induced the production of AOS. The production of AOS from adherent neutrophils to endothelial cells, but not to fibronectin or polystyrene, decreased with the interval time between the adhesion and the stimulation by PMA. The amount of AOS produced by the neutrophils adherent to fibronectin or polystyrene was maintained for one hour after stimulation with PMA, whereas that by suspended neutrophils gradually decreased with the time after stimulation. Results indicate that adherent and non-adherent neutrophils exhibit differing time course of AOS production.     

活性氧和线粒体ATP敏感钾通道介导肿瘤坏死因子α对缺氧/复氧心肌的保护作用

在培养的乳鼠心肌细胞上,研究肿瘤坏死因子α(TNF-α)对缺氧/复氧损伤心肌的保护作用的机制。结果发现：(1)用TNF-α(10—500U／ml)预处理,缺氧/复氧后心肌细胞内锰超氧化物歧化酶(Mn-SOD)活性增高、乳酸脱氢酶(LDH)释放量减少(P＜0．05);(2)用抗氧化剂N-乙酰半既氨酸(NAC,1mmol/L)、抗霉素A(antimycin A,50μmol/L)、2-巯基丙酰氨基乙酸(2-MPG,400μmol/L)和铜／锌超氧化物歧化酸(Cu/Zn,SOD)抑制剂二乙基二硫代氨基甲酸盐(DDC,100nmol/L)预处理,可取消TNF-α的抑制缺氧/复氧心肌细胞LDH释放和诱导Mn-SOD活性增高的作用;(3)mitoKATP通道抑制剂5-羟基癸酸(5-HD)预处理可阻断TNF-α对缺氧/复氧心肌细胞的保护作用;选择性mitoKATP通道开放剂diazoxide(50μmol/L)预处理可减少复氧后心肌细胞LDH的释放(P＜0．01),其作用可被5-HD(100μmol/L)和NAC所抑制。上述结果表明,活性氧和线粒体ATP敏感钾通道参与介导TNF-α对缺氧/复氧损伤的心肌保护作用。     

Environmental DNA fragment conferring early and increased sporulation and antibiotic production in Streptomyces species

Here we describe the rep gene, isolated from an environmental DNA library, which when transformed into Streptomyces species resulted in increased production of secondary metabolites and accelerated sporulation. We show that Streptomyces lividans strains bearing rep are particularly useful as expression hosts for heterologous antibiotic production.     

Enhanced activation of and increased production of matrix metalloproteinase-9 by human blood monocytes upon adhering to carbamylated collagen

Carbamylation refers to chemical modification of protein side chains by cyanate derived e.g. from urea. It alters their structural and functional properties. We have studied the influence of the carbamylation of type I collagen in vitro on its interactions with elutriated human monocytes, and its potential role in atherosclerosis. Adhesion of monocytes onto carbamylated collagen was significantly enhanced compared to native collagen. There was no change in superoxide anion production. On the other hand, there was an increase in the production and the activation of matrix metalloproteinase-9. No effect was found on tissue inhibitor of metalloproteinase-1 production. Thus, the presence of carbamylated collagen may stimulate the remodelling of extracellular matrix mediated by activated monocytes. Such alterations may contribute to enhanced atherosclerosis in renal insufficiency, a pathological condition associated with elevated levels of carbamylation.