4-Fluoro-2-methoxyphenol, an apocynin analog with enhanced inhibitory effect on leukocyte oxidant production and phagocytosis

Apocynin, a methoxy-substituted catechol (4-hydroxy-3-methoxyacetophenone), originally extracted from the roots of Picrorhiza kurroa, has been extensively used as a non-toxic inhibitor of the multienzymatic complex NADPH oxidase. We discovered that the analogous methoxy-substituted catechol, 4-Fluoro-2-methoxyphenol (F-apocynin), in which the acetyl group present in apocynin was changed to a fluorine atom, was significantly more potent as an inhibitor of NADPH oxidase activity, myeloperoxidase (MPO) chlorinating activity and phagocytosis of microorganisms by neutrophils; it was also as potent as apocynin in inhibiting tumor necrosis factor-alpha (TNF alpha) release by peripheral blood mononuclear cells. We attribute the increased potency of F-apocynin to its increased lipophilicity, which could facilitate the passage of the drug through the cell membrane. The inhibition of MPO chlorination activity, phagocytosis and TNF alpha release shows that apocynin and F-apocynin actions are not restricted to reactive oxygen species inhibition, but further studies are needed to clarify if these mechanisms are related. Like apocynin, F-apocynin did not show cell toxicity, and is a strong candidate for use in the treatment of inflammatory diseases. (C) 2011 Elsevier B.V. All rights reserved.

Crucial cytokine interactions in nitric oxide production induced by Mycoplasma arthritidis superantigen

Mycoplasma arthritidis causes autoimmune arthritis in rodents. It produces a superantigen (MAM) that simultaneously activates antigen presenting cells and T cells inducing nitric oxide and cytokine release. Nitric oxide is a key inducer and regulator of the immune system activation. Here, we investigated nitric oxide and cytokine production and interactions of these molecules in MAM-stimulated co-cultures of macrophages (J774A.1 cell line) with spleen lymphocytes. We found that: a) MAM-induced nitric oxide, interferon-gamma, membrane-associated tumor necrosis factor and interleukin-2 production in co-cultures of macrophages with lymphocytes from BALB/c and C3H/HePas but not from C57B1/6 mice; b) production of nitric oxide was dependent on interferon-gamma whereas that of interferon-gamma was dependent on interleukin-2 and membrane-associated tumor necrosis factor; c) these cytokines up regulated MAM-induced nitric oxide production. Unraveling the mechanisms of cell activation induced by MAM might be helpful to design strategies to prevent immune system activation by superantigens and therefore in seeking amelioration of associated immunopathologies. (C) 2008 Elsevier Masson SAS. All rights reserved.

CD4(+) CD25(+) Foxp3(+) Regulatory T Cells, Dendritic Cells, and Circulating Cytokines in Uncomplicated Malaria: Do Different Parasite Species Elicit Similar Host Responses?

Clearing blood-stage malaria parasites without inducing major host pathology requires a finely tuned balance between pro- and anti-inflammatory responses. The interplay between regulatory T (Treg) cells and dendritic cells (DCs) is one of the key determinants of this balance. Although experimental models have revealed various patterns of Treg cell expansion, DC maturation, and cytokine production according to the infecting malaria parasite species, no studies have compared all of these parameters in human infections with Plasmodium falciparum and P. vivax in the same setting of endemicity. Here we show that during uncomplicated acute malaria, both species induced a significant expansion of CD4(+) CD25(+) Foxp3(+) Treg cells expressing the key immunomodulatory molecule CTLA-4 and a significant increase in the proportion of DCs that were plasmacytoid (CD123(+)), with a decrease in the myeloid/plasmacytoid DC ratio. These changes were proportional to parasite loads but correlated neither with the intensity of clinical symptoms nor with circulating cytokine levels. One-third of P. vivax-infected patients, but no P. falciparum-infected subjects, showed impaired maturation of circulating DCs, with low surface expression of CD86. Although vivax malaria patients overall had a less inflammatory cytokine response, with a higher interleukin-10 (IL-10)/tumor necrosis factor alpha (TNF-alpha) ratio, this finding did not translate to milder clinical manifestations than those of falciparum malaria patients. We discuss the potential implications of these findings for species-specific pathogenesis and longlasting protective immunity to malaria.

Interleukin-10 attenuates vascular responses to endothelin-1 via effects on ERK1/2-dependent pathway

Giachini FR, Zemse SM, Carneiro FS, Lima VV, Carneiro ZN, Callera GE, Ergul A, Webb RC, Tostes RC. Interleukin-10 attenuates vascular responses to endothelin-1 via effects on ERK1/2-dependent pathway. Am J Physiol Heart Circ Physiol 296: H489-H496, 2009. First published December 12, 2008; doi:10.1152/ajpheart.00251.2008.-Interleukin-10 (IL-10) is an anti-inflammatory cytokine with protective actions on the vasculature. On the other hand, endothelin ( ET)-1 has potent vasoconstrictor, mitogenic, and proinflammatory activities, which have been implicated in the pathophysiology of a number of cardiovascular diseases. We hypothesized that, in a condition where ET-1 expression is upregulated, i.e., on infusion of TNF-alpha, IL-10 confers vascular protection from ET-1-induced injury. Aortic rings and first-order mesenteric arteries from male C57BL/6 (WT) and IL-10-knockout (IL-10(-/-)) mice were treated with human recombinant TNF-alpha (220 ng.kg(-1).day(-1)) or vehicle (saline) for 14 days. TNF-alpha infusion significantly increased blood pressure in IL-10(-/-), but not WT, mice. TNF-alpha augmented vascular ET-1 mRNA expression in arteries from WT and IL-10(-/-) mice. ET type A (ETA) receptor expression was increased in arteries from IL-10(-/-) mice, and TNF-alpha infusion did not change vascular ETA receptor expression in control or IL-10(-/-) mice. Aorta and mesenteric arteries from TNF-alpha-infused IL-10(-/-) mice displayed increased contractile responses to ET-1, but not the ET type B receptor agonist IRL-1620. The ETA receptor antagonist atrasentan completely abolished responses to ET-1 in aorta and mesenteric vessels, whereas the ERK1/2 inhibitor PD-98059 abrogated increased contractions to ET-1 in arteries from TNF-alpha-infused IL-10(-/-) mice. Infusion of TNF-alpha, as well as knockdown of IL-10 (IL-10(-/-)), induced an increase in total and phosphorylated ERK1/2. These data demonstrate that IL-10 counteracts ET(A)-mediated vascular responses to ET-1, as well as activation of the ERK1/2 pathway.

CDK9 a potential target for drug development

The family of Cyclin-Dependent Kinases (CDKs) can be subdivided into two major functional groups based on their roles in cell cycle and/or transcriptional control. CDK9 is the catalytic subunit of positive transcription elongation factor b (P-TEFb). CDK9 is the kinase of the TAK complex (Tat-associated kinase complex), and binds to Tat protein of HIV, suggesting a possible role for CDK9 in AIDS progression. CDK9 complexed with its regulatory partner cyclin T1, serves as a cellular mediator of the transactivation function of the HIV Tat protein. P-TEFb is responsible for the phosphorylation of the carboxyl-terminal domain of RNA Pol II, resulting in stimulation of transcription. Furthermore, the complexes containing CDK9 induce the differentiation in distinct tissue. The CDK9/cyclin T1 complex is expressed at higher level in more differentiated primary neuroectodermal and neuroblastoma tumors, showing a correlation between the kinase expression and tumor differentiation grade. This may have clinical and therapeutical implications for these tumor types. Among the CDK inhibitors two have shown to be effective against CDK9: Roscovitine and Flavopiridol. These two inhibitors prevented the replication of human immunodeficiency virus (HIV) type 1 by blocking Tat transactivation of the HIV type 1 promoter. These compounds inhibit CDKs by binding to the catalytic domain in place of ATP, preventing transfer of a phosphate group to the substrate. More sensitive therapeutic agents of CDK9 can be designed, and structural studies can add information in the understanding of this kinase. The major features related to CDK9 inhibition will be reviewed in this article.

Ação do extrato metanólico e etanólico de Davilla elliptica St. Hill. (Malpighiaceae) na resposta imune

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The role of obesity as a modifying factor in patients undergoing non-surgical periodontal therapy

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Sporothrix schenckii lipid inhibits macrophage phagocytosis: Involvement of nitric oxide and tumour necrosis factor-alpha

The role of cell-wall compounds in the immune response to sporotrichosis is unknown. The effect of cell-wall compounds and exoantigen obtained from Sporothrix schenckii in macrophage/fungus interaction was analysed with respect to nitric oxide (NO) and tumour necrosis factor-alpha (TNF-alpha). The lipid compound of the cell wall plays an important role in the pathogenesis of this mycosis and was found to inhibit the phagocytic process and to induce high liberation of NO and TNF-alpha in macrophage cultures in the present study. This is a very interesting result because it is the first report about one compound of the fungus S. schenckii that presents this activity.

4-Fluoro-2-methoxyphenol, an apocynin analog with enhanced inhibitory effect on leukocyte oxidant production and phagocytosis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

TLR4 and CD14 receptors expressed in rat pineal gland trigger NFKB pathway

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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 noncarriers. 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.

Inflammatory cytokine mRNA detection by real time PCR in chorioamniotic membranes from pregnant women with preterm premature rupture of membranes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Inhibitory effect of silibinin on tumour necrosis factor-alpha and hydrogen peroxide production by human monocytes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Periodontal Disease Decreases Insulin Sensitivity and Insulin Signaling

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)