Functional interferences in host inflammatory immune response by airway allergic inflammation restrain experimental periodontitis development in mice

Aims Periodontal disease (PD) and airway allergic inflammation (AL) present opposing inflammatory immunological features and clinically present an inverse correlation. However, the putative mechanisms underlying such opposite association are unknown. Material and Methods Balb/C mice were submitted to the co-induction of experimental PD (induced by Actinobacillus actinomycetemcomitans oral inoculation) and AL [induced by sensitization with ovalbumin (OVA) and the subsequent OVA challenges], and evaluated regarding PD and AL severity, immune response [cytokine production at periodontal tissues, and T-helper transcription factors in submandibular lymph nodes (LNs)] and infection parameters. Results PD/AL co-induction decreased PD alveolar bone loss and periodontal inflammation while experimental AL parameters were unaltered. An active functional interference was verified, because independent OVA sensitization and challenge not modulate PD outcome. PD+AL group presented decreased tumour necrosis factor-alpha (TNF-alpha), interleukin (IL)-1 beta, -gamma, IL-17A, receptor activator of nuclear factor kappa-light-chain-enhancer of activated B cells ligand and matrix metalloproteinase (MMP)-13 levels in periodontal tissues, while IL-4 and IL-10 levels were unaltered by AL co-induction. AL co-induction also resulted in upregulated T-bet and related orphan receptor gamma and downregulated GATA3 levels expression in submandibular LNs when compared with PD group. Conclusion Our results demonstrate that the interaction between experimental periodontitis and allergy involves functional immunological interferences, which restrains experimental periodontitis development by means of a skewed immune response.

Evidences of the cooperative role of the chemokines CCL3, CCL4 and CCL5 and its receptors CCR1+and CCR5+in RANKL+ cell migration throughout experimental periodontitis in mice

Periodontal disease (PD) is characterized by the inflammatory bone resorption in response to the bacterial challenge, in a host response that involves a series of chemokines supposed to control cell influx into periodontal tissues and determine disease outcome. In this study, we investigated the role of chemokines and its receptors in the immunoregulation of experimental PD in mice. Aggregatibacter actinomycetemcomitans-infected C57BI/6 (WT) mice developed an intense inflammatory reaction and severe alveolar bone resorption, associated with a high expression of CCL3 and the migration of CCR5+, CCR1+ and RANKL+ cells to periodontal tissues. However, CCL3KO-infected mice developed a similar disease phenotype than WT strain, characterized by the similar expression of cytokines (TNF-alpha, IFN-gamma and IL-10), osteoclastogenic factors (RANKL and OPG) and MMPs (MMP-1, MMP-2, MMP-3, TIMP-1 and TIMP-3), and similar patterns of CCR1+, CCR5+ and RANKL+ cell migration. The apparent lack of function for CCL3 is possible due the relative redundancy of chemokine system, since chemokines such as CCL4 and CCL5, which share the receptors CCR1 and CCR5 with CCL3, present a similar kinetics of expression than CCL3. Accordingly, CCL4 and CCL5 kinetics of expression after experimental periodontal infection remain unaltered regardless the presence/absence of CCL3. Conversely, the individual absence of CCR1 and CCR5 resulted in a decrease of leukocyte infiltration and alveolar bone loss. When CCR1 and CCR5 were simultaneously inhibited by met-RANTES treatment a significantly more effective attenuation of periodontitis progression was verified, associated with lower values of bone loss and decreased counts of leukocytes in periodontal tissues. Our results suggest that the absence of CCL3 does not affect the development of experimental PD in mice, probably due to the presence of homologous chemokines CCL4 and CCL5 that overcome the absence of this chemokine. In addition, our data demonstrate that the absence of chemokine receptors CCR1+ and CCR5+ attenuate of inflammatory bone resorption. Finally, our data shows data the simultaneous blockade of CCR1 and CCR5 with MetRANTEs presents a more pronounced effect in the arrest of disease progression, demonstrating the cooperative role of such receptors in the inflammatory bone resorption process throughout experimental PD. (C) 2009 Elsevier Inc. All rights reserved.

CCR2 Deficiency Results in Increased Osteolysis in Experimental Periapical Lesions in Mice

Introduction: Periapical lesions are chronic inflammatory disorders of periradicular tissues caused by etiologic agents of endodontic origin. The inflammatory chemokines are thought to be involved in the latter observed osteolysis. With a murine model of experimental periapical lesion, the objective of this study was to evaluate the role of the chemokine receptor CCR2 in the lesion progression, osteoclast differentiation and activation, and expression of inflammatory osteolysis-related mediators. Methods: For lesion induction, right mandibular first molars were opened surgically with a (1)/(4) carbine bur, and 4 bacterial strains were inoculated in the exposed dental pulp; left mandibular first molars were used as controls. Animals were killed at 3, 7, 14, and 21 days after surgeries to evaluate the kinetics of lesion development. Results: CCR2 KO mice showed wider lesions than WT mice. CCR2 KO mice also expressed higher levels of the osteoclastogenic and osteolytic factors, receptor activator of nuclear factor kappa B ligand (RANKL) and cathepsin K, of the proinflammatory cytokine tumor necrosis factor alpha, and of the neutrophil migration related chemokine, KC. Conclusions: These results suggest that CCR2 is important in host protection to periapical osteolysis. (J Endod 2010;36:244-250)

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.

Heme Impairs Prostaglandin E(2) and TGF-beta Production by Human Mononuclear Cells via Cu/Zn Superoxide Dismutase: Insight into the Pathogenesis of Severe Malaria

In many hemolytic disorders, such as malaria, the release of free heme has been involved in the triggering of oxidative stress and tissue damage. Patients presenting with severe forms of malaria commonly have impaired regulatory responses. Although intriguing, there is scarce data about the involvement of heme on the regulation of immune responses. In this study, we investigated the relation of free heme and the suppression of anti-inflammatory mediators such as PGE(2) and TGF-beta in human vivax malaria. Patients with severe disease presented higher hemolysis and higher plasma concentrations of Cu/Zn superoxide dismutase (SOD-1) and lower concentrations of PGE(2) and TGF-beta than those with mild disease. In addition, there was a positive correlation between SOD-1 concentrations and plasma levels of TNF-alpha. During antimalaria treatment, the concentrations of plasma SOD-1 reduced whereas PGE(2) and TGF-beta increased in the individuals severely ill. Using an in vitro model with human mononuclear cells, we demonstrated that the heme effect on the impairment of the production of PGE(2) and TGF-beta partially involves heme binding to CD14 and depends on the production of SOD-1. Aside from furthering the current knowledge about the pathogenesis of vivax malaria, the present results may represent a general mechanism for hemolytic diseases and could be useful for future studies of therapeutic approaches. The Journal of Immunology, 2010, 185: 1196-1204.

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.

Retinoic acid inhibits dendritic cell differentiation driven by interleukin-4

All-trans-retinoic acid (atRA) appears to affect Th1-Th2 differentiation and its effects on immune responses might also be mediated by dendritic cell (DC). Nonetheless, studies have been showing contradictory results since was observed either induction or inhibition of DC differentiation. Our aim was to investigate atRA action on human monocyte derived DC differentiation. For this purpose we tested pharmacological and physiological doses of atRA with or without cytokines. Cell phenotypes were analyzed by flow cytometry and function was investigated by phagocytosis and respiratory burst. DC, positive control group, was differentiated with GM-CSF and IL-4 and maturated with TNF-alpha. We demonstrated that atRA effects depend on the dose used as pharmacological doses inhibited expression of all phenotypic markers tested while a physiological dose caused cell differentiation. However, atRA combined or not with cytokines did not promote DC differentiation. In fact, atRA was detrimental on IL-4 property as a DC inductor. (C) 2009 Elsevier Inc. All rights reserved.

Depot-specific modulation of adipokine levels in rat adipose tissue by diet-induced obesity: The effect of aerobic training and energy restriction

The present study examined the effects of aerobic training and energy restriction on adipokines levels in mesenteric (MEAT) and retroperitoneal (RPAT) white adipose tissue from obese rats. Male Wistar rats were fed with standard laboratory diet (Control group) or high fat diet (HFD). After 15 weeks, HFD rats were randomly assigned to the following groups: rats submitted to HFD, which were sedentary (sedentary HFD, n = 8) or trained (trained HFD, n = 8); or submitted to energy-restriction (ER), which were sedentary (sedentary ER, n = 8) or trained (trained ER, n = 8). Trained rats ran on a treadmill at 55% VO(2max) for 60 min/day, 5 days/week, for 10 weeks. ER rats were submitted to a reduction of 20% daily caloric ingestion compared to the Control group. ER and aerobic training decreased body weight, MEAT and RPAT absolute weight, and fat mass. IL-6, IL-10 and TNF-alpha levels were decreased and adiponectin did not change in RPAT in response to ER protocol. On the other hand, ER and the aerobic training protocol decreased IL-6, TNF-alpha and adiponectin levels in MEAT. Absolute MEAT weight showed a positive correlation with IL-6 (r = 0.464), INF-alpha (r = 0.508); and adiponectin (r = 0.342). These results suggest a tissue-specific heterogeneous response in adipokines level. The combination of the protocols (aerobic training and energy restriction) did not induce an enhanced effect. Published by Elsevier Ltd.

Macrophage suppression following phagocytosis of apoptotic neutrophils is mediated by the S100A9 calcium-binding protein

The clearance of apoptotic cells by phagocytes is a fundamental process during tissue remodeling and resolution of inflammation. In turn, the phagocytosis of apoptotic cells generates signals that suppress pro-inflammatory activation of macrophages. These events occur during the resolution phase of inflammation and therefore the malfunctioning of this process may lead to inflammation-related tissue damage. Here, we demonstrate that the calcium-binding protein S100A9, normally abundant in the cytoplasm of neutrophils and also released by apoptotic neutrophils, is involved in the suppression of macrophages after the uptake of apoptotic neutrophils. Both, spontaneous and induced production of inflammatory species (nitric oxide, hydrogen peroxide and TNF-alpha) as well as the phagocytic activity were inhibited when macrophages were in presence of apoptotic neutrophils, conditioned medium from neutrophil cultures or a peptide corresponding to the C-terminal region of S100A9 protein. On the other hand, macrophages kept in the conditioned medium of neutrophils that was previously depleted of S100A9 were shown to resume the activated status. Finally, we demonstrate that the calcium-binding property of S100A9 might play a role in the suppression process, since the stimulation of intracellular calcium release with ionomycin significantly reversed the effects of the uptake of apoptotic neutrophils in macrophages. In conclusion, we propose that S100A9 is a novel component of the regulatory mechanisms of inflammation, acting side-by-side with other suppressor factors generated upon ingestion of apoptotic cells. (C) 2009 Elsevier GmbH. All rights reserved.

Anti-inflammatory effect of atorvastatin ameliorates insulin resistance in monosodium glutamate-treated obese mice

Considering that inflammation contributes to obesity-induced insulin resistance and that statins have been reported to have other effects beyond cholesterol lowering, the present study aimed to it whether atorvastatin treatment has anti-inflammatory action in white adipose tissue of obese mice, consequently improving insulin sensitivity. Insulin sensitivity in vivo (by insulin tolerance test); metabolic-hormonal profile; plasma tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and adiponectin; adipose tissue immunohistochemistry; glucose transporter (GLUT) 4; adiponectin; INF-alpha; IL-1 beta; and IL-6 gene expression; and I kappa B kinase (IKK)-alpha/beta activity were assessed in 23-week-old monosodium glutamate induced obese mice untreated or treated with atorvastatin for 4 weeks. Insulin-resistant obese mice had increased plasma triglyceride, insulin, TNF-alpha, and IL-6 plasma levels. Adipose tissue of obese animals showed increased macrophage infiltration, IKK-alpha (42%, P < .05) and IKK-beta (73%, P < .05) phosphorylation, and INF-alpha and IL-6 messenger RNA (mRNA) (similar to 15%, P < .05) levels, and decreased GLUT4 mRNA and protein (30%, P < .05) levels. Atorvastatin treatment lowered cholesterol, triglyceride, insulin, INF-alpha, and IL-6 plasma levels, and restored whole-body insulin sensitivity. In adipose tissue, atorvastatin decreased macrophage in and normalized IKK-alpha/beta phosphorylation; INF-alpha, IL-6, and GLUT4 mRNA; and GLUT4 protein to control levels. The present findings demonstrate that atorvastatin has anti-inflammatory effects on adipose tissue of obese mice, which may be important to its local and whole-body insulin-sensitization effects. (C) 2010 Published by Elsevier Inc.

Chronic exercise decreases cytokine production in healthy rat skeletal muscle

Skeletal muscle is the source of pro- and anti-inflammatory cytokines, and recently, it has been recognized as an important source of interleukin-6 (IL-6). Acute physical exercise is known to induce a pro-inflammatory cytokine profile in the plasma. However, the effect of chronic physical exercise in the production of pro- and anti-inflammatory cytokines by the skeletal muscle has never been examined. We assessed IL-6, TNF-alpha, IL-1 beta and IL-10 levels in the skeletal muscle of rats submitted to endurance training. Animals were randomly assigned to either a Sedentary group (S, n = 7) or an endurance exercise trained group (T, n = 8). Trained rats ran on a treadmill for 5 days week(-1) for 8 weeks (60% VO(2max)). Detection of IL-6, TNF-alpha, IL-1 beta and IL-10 protein expression was carried out by ELISA. We found decreased expression of IL-1 beta, IL-6, TNF-alpha and IL-10 (28%, 27%. 32% and 37%, respectively, p < 0.05) in the extensor digital longus (EDL) from T, when compared with S. In the soleus, IL-1 beta, TNF-alpha and IL-10 protein levels were similarly decreased (34%, 42% and 50%, respectively, p < 0.05) in T in relation to S, while IL-6 expression was not affected by the training protocol. In conclusion, exercise training induced decreased cytokine protein expression in the skeletal muscle. These data show that in healthy rats, 8-week moderate-intensity aerobic training down regulates skeletal muscle production of cytokines involved in the onset, maintenance and regulation of inflammation, and that the response is heterogeneous according to fibre composition. Copyright (C) 2009 John Wiley & Sons, Ltd.

Exhaustive exercise causes an anti-inflammatory effect in skeletal muscle and a pro-inflammatory effect in adipose tissue in rats

It is well known that exhaustive exercise increases serum and skeletal muscle IL-6 concentrations. However, the effect of exhaustive exercise on the concentrations of other cytokines in the muscle and in the adipose tissue is controversial. The purpose of this study was to evaluate the effect of exhaustive exercise on mRNA and protein expression of IL-10, TNF-alpha and IL-6 in different types of skeletal muscle (EDL, soleus) and in two different depots of white adipose tissue (mesenteric-MEAT and retroperitoneal-RPAT). Rats were killed by decapitation immediately (E0 group, n = 6), 2 (E2 group, n = 6) and 6 (E6 group, n = 6) hours after the exhaustion protocol, which consisted of running on a treadmill (approximately 70% VO(2max) for 50 min and then subsequently at an elevated rate that increased at 1 m/min every minute, until exhaustion). The control group (C group, n = 6) was not subjected to exercise. Cytokine protein expression increased in EDL, soleus, MEAT and RPAT from all exercised groups, as detected by ELISA. EDL IL-10 and TNF-alpha expression was higher than that of the soleus. The IL-10/TNF-alpha ratio was increased in the skeletal muscle, especially in EDL, but it was found to be decreased in the adipose tissue. These results show that exhaustive exercise presents a different effect depending on the tissue which is analysed: in the muscle, it induces an anti-inflammatory effect, especially in type 2 fibres, while the pro-inflammatory effect prevails in adipose tissue, possibly contributing to increased lipolysis to provide energy for the exercising muscle.

Angiotensin II modulates CD40 expression in vascular smooth muscle cells

The signalling pathway CD40/CD40L (CD40 ligand) plays an important role in atherosclerotic plaque formation and rupture. AngII (angiotensin II), which induces oxidative stress and inflammation, is also implicated in the progression of atherosclerosis. In the present study, we tested the hypothesis that AngII increases CD40/CD40L activity in vascular cells and that ROS (reactive oxygen species) are part of the signalling cascade that controls CD40/CD40L expression. Human CASMCs (coronary artery smooth muscle cells) in culture exposed to IL (interleukin)-1 beta or TNF-alpha (tumour necrosis factor-a) had increased superoxide generation and enhanced CD40 expression, detected by EPR (electron paramagnetic resonance) and immunoblotting respectively. Both phenomena were abolished by previous incubation with membrane-permeant antioxidants or cell transfection with P22(phox) antisense. AngII (50-200 nmol/l) induced an early and sustained increase in CD40 mRNA and protein expression in CASMCs, which was blocked by treatment with antioxidants. Increased CD40 expression led to enhanced activity of the pathway, as AngII-treated cells stimulated with recombinant CD40L released higher amounts of IL-8 and had increased COX-2 (cyclo-oxygenase-2) expression. We conclude that AngII stimulation of vascular cells leads to a ROS-dependent increase in CD40/CD40L signalling pathway activity. This phenomenon may be an important mechanism modulating the arterial injury observed in atherosclerosis-related vasculopathy.

Inactivation of formyltransferase (wbkC) gene generates a Brucella abortus rough strain that is attenuated in macrophages and in mice

Rough mutants of Brucella abortus were generated by disruption of wbkC gene which encodes the formyltransferase enzyme involved in LPS biosynthesis. In bone marrow-derived macrophages the B. abortus Delta wbkC mutants were attenuated, could not reach a replicative niche and induced higher levels of IL-12 and TNF-alpha when compared to parental smooth strains. Additionally, mutants exhibited attenuation in vivo in C57BL/6 and interferon regulatory factor-1 knockout mice. Delta wbkC mutant strains induced lower protective immunity in C56BL/6 than smooth vaccine S19 but similar to rough vaccine RB51. Finally, we demonstrated that Brucella wbkC is critical for LPS biosynthesis and full bacterial virulence. (C) 2010 Elsevier Ltd. All rights reserved.

Discovery of Phthalimides as Immunomodulatory and Antitumor Drug Prototypes

Brazilian National Council of Research (CNPq)[471834/2006-8]