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

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Melatonin effects on macrophage in diabetic rats and the maternal hyperglycemic implications for newborn rats

The modulatory effects of melatonin (MLT) on maternal and fetal macrophages in diabetic rats and the repercussion of maternal hyperglycemia on fetus-placenta parameters were studied. This was achieved by determining maternal and fetal blood glucose, weight and superoxide release by macrophages. Placental weight, protein, DNA and RNA concentration were also verified. Superoxide levels in macrophages isolated from pregnant healthy rats were higher than those obtained from diabetic animals. Melatonin increased significantly in the macrophages of control animals (18.7 ± 2.8 with MLT compared to 14.2 ± 1.6 without MLT) but decreased with melatonin stimulation in diabetic rats (8.8 ± 1.4 with MLT compared to 12.9 ± 2.1 without MLT). Melatonin significantly decreased superoxide levels in newborns of diabetic mothers (7.3 ± 3.4) compared to those of healthy (14.6 ± 3.5) mothers. Blood glucose levels were significantly higher (p<0.05) in newborn rats of diabetic mothers (108.3 ± 7.8) compared to blood glucose levels in newborn control rats (81.2 ± 10.7). Body weight was significantly higher (p <0.05) in the offspring of rats with alloxan-induced diabetes. No statistical difference (p> 0.05) was observed in the placenta weight, total protein concentration and DNA of rats. The RNA concentration was significantly lower (p <0.05) in the placentas of rats with alloxan-induced diabetes (156.1 ± 71.8), when compared to the concentration of RNA in the placentas of control rats (239.5 ± 77.3). In conclusion, maternal hyperglycemia modified the fetus-placental parameters and melatonin modulated the macrophages activation in maternal and fetal diabetic rats.

Macrophage migration inhibitory factor and oral cancer

Background: Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine with pro-inflammatory functions and involved in tumorigenesis. The aim of this study was to evaluate the expression and localization of the macrophage MIF in oral squamous carcinoma (OSC). In addition, the relationship between MIF expression and clinicopathological parameters such as survival data, tobacco use, alcohol habits, TNM stage, tumor graduation, and peritumoral inflammatory infiltrate were evaluated. Methods: Using immunohistochemistry, expression and localization of MIF was detected in 44 specimens of OSC. The absolute number and relative proportions of MIF-positive cells detected were also determined separately for tumor parenchyma vs. stroma. All counts were determined from 10 consecutive high-power fields using an integration graticule. Moreover, some parameters were analyzed separately for lip and intra-oral cancers. Results: Migration inhibitory factor-positive cells were observed in both the tumor parenchyma and in inflammatory cells of all specimens. In contrast, MIF expression was not detected in tumoral nests associated with poorly differentiated tumors. In specimens of lip cancer, a greater number of MIF-positive stromal immune cells were detected than in intra-oral cancer specimens (Mann-Whitney test, P = 0.049). Conclusions: Oral squamous carcinoma cells consistently express MIF independent of their location. Lip tumors presented more MIF-positive peritumoral inflammatory cells, similar to control, suggesting that immunological differences in leukocyte activation exist between in lip and intra-oral cancers. © 2012 John Wiley & Sons A/S.

Propolis and its constituent caffeic acid suppress LPS-stimulated pro-inflammatory response by blocking NF-κB and MAPK activation in macrophages

Ethnopharmacological relevance Propolis is a bee product with numerous biological and pharmacological properties, such as immunomodulatory and anti-inflammatory activities. It has been used in folk medicine as a healthy drink and in food to improve health and prevent inflammatory diseases. However, little is known about its mechanism of action. Thus, the goal of this study was to verify the antioxidant activity and to explore the anti-inflammatory properties of propolis by addressing its intracellular mechanism of action. Caffeic acid was investigated as a possible compound responsible for propolis action. Materials and methods The antioxidant properties of propolis and caffeic acid were evaluated by using the 2,2-Diphenyl-1-picrylhydrazyl free radical (DPPH) scavenging method. To analyze the anti-inflammatory activity, Raw 264.7 macrophages were treated with different concentrations of propolis or caffeic acid, and nitric oxide (NO) production, a strong pro-inflammatory mediator, was evaluated by the Griess reaction. The concentrations of propolis and caffeic acid that inhibited NO production were evaluated on intracellular signaling pathways triggered during inflammation, namely p38 mitogen-activated protein kinase (MAPK), c-jun NH2-terminal kinase (JNK1/2), the transcription nuclear factor (NF)-κB and extracellular signal-regulated kinase (ERK1/2), through Western blot using specific antibodies. A possible effect of propolis on the cytotoxicity of hepatocytes was also evaluated, since this product can be used in human diets. Results Caffeic acid showed a higher antioxidant activity than propolis extract. Propolis and caffeic acid inhibited NO production in macrophages, at concentrations without cytotoxicity. Furthermore, both propolis and caffeic acid suppressed LPS-induced signaling pathways, namely p38 MAPK, JNK1/2 and NF-κB. ERK1/2 was not affected by propolis extract and caffeic acid. In addition, propolis and caffeic acid did not induce hepatotoxicity at concentrations with strong anti-inflammatory potential. Conclusions Propolis exerted an antioxidant and anti-inflammatory action and caffeic acid may be involved in its inhibitory effects on NO production and intracellular signaling cascades, suggesting its use as a natural source of safe anti-inflammatory drugs. © 2013 Elsevier B.V.

SOCS3 expression correlates with severity of inflammation, expression of proinflammatory cytokines, and activation of STAT3 and p38 MAPK in LPS-induced inflammation in vivo

SOCS3 is an inducible endogenous negative regulator of JAK/STAT pathway, which is relevant in inflammatory conditions. We used a model of LPS-induced periodontal disease in rats to correlate SOCS3 expression with the inflammatory status. In vitro we used a murine macrophage cell line to assess the physical interaction between SOCS3 and STAT3 by coimmunoprecipitation. 30 ug of LPS from Escherichia coli were injected in the gingival tissues on the palatal aspect of first molars of the animals 3x/week for up to 4 weeks. Control animals were injected with the vehicle (PBS). The rats were sacrificed at 7, 15, and 30 days. Inflammation and gene expression were assessed by stereometric analysis, immunohistochemistry, RT-qPCR, and western blot. LPS injections increased inflammation, paralleled by an upregulation of SOCS3, of the proinflammatory cytokines IL-1β, IL-6, and TNF-and increased phosphorylation of STAT3 and p38 MAPK. SOCS3 expression accompanied the severity of inflammation and the expression of proinflammatory cytokines, as well as the activation status of STAT3 and p38 MAPK. LPS stimulation in a macrophage cell line in vitro induced transient STAT3 activation, which was inversely correlated with a dynamic physical interaction with SOCS3, suggesting that this may be a mechanism for SOCS3 regulatory function. © 2013 João Antônio Chaves de Souza et al.

Signaling Pathways Activation by Primary Endodontic Infectious Contents and Production of Inflammatory Mediators

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

Hypusine Modification of the Ribosome-binding Protein eIF5A, a Target for New Anti-Inflammatory Drugs: Understanding the Action of the Inhibitor GC7 on a Murine Macrophage Cell Line

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

Specific Activation of an I-Like Element in Drosophila Interspecific Hybrids

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

Lack of beta(2)-AR improves exercise capacity and skeletal muscle oxidative phenotype in mice

beta(2)-adrenergic receptor (beta(2)-AR) agonists have been used as ergogenics by athletes involved in training for strength and power in order to increase the muscle mass. Even though anabolic effects of beta(2)-AR activation are highly recognized, less is known about the impact of beta(2)-AR in endurance capacity. We presently used mice lacking beta(2)-AR [beta(2)-knockout (beta(2) KO)] to investigate the role of beta(2)-AR on exercise capacity and skeletal muscle metabolism and phenotype. beta(2) KO mice and their wild-type controls (WT) were studied. Exercise tolerance, skeletal muscle fiber typing, capillary-to-fiber ratio, citrate synthase activity and glycogen content were evaluated. When compared with WT, beta 2KO mice displayed increased exercise capacity (61%) associated with higher percentage of oxidative fibers (21% and 129% of increase in soleus and plantaris muscles, respectively) and capillarity (31% and 20% of increase in soleus and plantaris muscles, respectively). In addition, beta 2KO mice presented increased skeletal muscle citrate synthase activity (10%) and succinate dehydrogenase staining. Likewise, glycogen content (53%) and periodic acid-Schiff staining (glycogen staining) were also increased in beta 2KO skeletal muscle. Altogether, these data provide evidence that disruption of beta(2)AR improves oxidative metabolism in skeletal muscle of beta 2KO mice and this is associated with increased exercise capacity.

Local Injections of Adipose-Derived Mesenchymal Stem Cells Modulate Inflammation and Increase Angiogenesis Ameliorating the Dystrophic Phenotype in Dystrophin-Deficient Skeletal Muscle

The effects of adipose-derived mesenchymal stem cells (ADMSC) transplantation on degeneration, regeneration and skeletal muscle function were investigated in dystrophin-deficient mice (24-week-old). ADMSC transplantation improved muscle strength and, resistance to fatigue. An increase in fiber cross-sectional area and in the number of fibers with centralized nuclei and augment of myogenin content were observed. In ADMSC-treated muscles a decrease in muscle content of TNF-alpha, IL-6 and oxidative stress measured by Amplex(A (R)) reagent were observed. The level of TGF-beta 1 was lowered whereas that of VEGF, IL-10 and IL-4 were increased by ADMSC treatment. An increase in markers of macrophage M1 (CD11 and F4-80) and a decrease in T lymphocyte marker (CD3) and arginase-1 were also observed in ADMSCs-treated dystrophic muscle. No change was observed in iNOS expression. Increased phosphorylation of Akt, p70S6k and 4E-BP1 was found in dystrophic muscles treated with ADMSC. These results suggest that ADMSC transplantation modulates inflammation and improves muscle tissue regeneration, ameliorating the dystrophic phenotype in dystrophin-deficient mice.

Apoptotic Cells Contribute to Melanoma Progression and This Effect is Partially Mediated by the Platelet-Activating Factor Receptor

There is evidence that the platelet-activating factor receptor (PAFR) is involved in the clearance of apoptotic cells by macrophages, and that this is associated with anti-inflammatory phenotype. Our group has previously shown that coinjection of a large number of apoptotic cells can promote tumor growth from a subtumorigenic dose of melanoma cells. Here, we studied the involvement of the PAFR in the tumor growth promoting effect of apoptotic cells. A sub-tumorigenic dose of melanoma cells (Tm1) was coinjected with apoptotic Tm1 cells, subcutaneously in the flank of C57Bl/6 mice, and the volume was monitored for 30 days. Animals received the PAFR antagonists, WEB2170 or PCA4248 (5 mg/kg body weight) or vehicle, by peritumoral daily injection for 5 days. Results showed that PAFR antagonists significantly inhibited the tumor growth induced by the coinjection of a subtumorigenic dose of melanoma cells together with apoptotic cells. This was accompanied by inhibition of early neutrophil and macrophage infiltration. Addition of (platelet-activating factor) to this system has no significant effect. PAFR antagonists did not affect the promoting effect of carrageenan. We suggest that the recognition of apoptotic cells by phagocytes leads to activation of PAFR pathways, resulting in a microenvironment response favorable to melanoma growth.

Activation pattern of neutrophils from blood of elderly individuals with -related denture stomatitis

We have identified impaired neutrophils in elderly individuals which could be involved with -related denture stomatitis (DS), an oral infection predominantly caused by , affecting especially elderly individuals using dental prosthesis. However, specific mechanisms performed by neutrophil contributing to the susceptibility of the elderly to DS are not fully understood. This study evaluated activation features of blood neutrophils from elderly and young individuals with DS. Blood neutrophils cultured with . from elderly subjects secreted decreased levels of CXCL8. However, . challenged-neutrophils from DS patients produced high IL-4 and IL-10, and low GM-CSF levels, regardless of age. Additional elastase activity of neutrophils from both elderly groups was detected after incubation with . , but only neutrophils from elderly DS demonstrated high myeloperoxidase activity. Therefore, DS patients have affected neutrophils, and the advance of age intensifies these damages. In sumamry, individuals with -related denture stomatitis presented variation in the neutrophil phenotype and activation. Such alterations were more intense in neutrophils from infected elderly individuals.

Acute heat stress impairs performance parameters and induces mild intestinal enteritis in broiler chickens: Role of acute hypothalamic-pituitary-adrenal axis activation

Studies on the environmental consequences of stress are relevant for economic and animal welfare reasons. We recently reported that long-term heat stressors (31 +/- 1 degrees C and 36 +/- 1 degrees C for 10 h/d) applied to broiler chickens (Gallus gallus domesticus) from d 35 to 42 of life increased serum corticosterone concentrations, decreased performance variables and the macrophage oxidative burst, and produced mild, multifocal acute enteritis. Being cognizant of the relevance of acute heat stress on tropical and subtropical poultry production, we designed the current experiment to analyze, from a neuroimmune perspective, the effects of an acute heat stress (31 +/- 1 degrees C for 10 h on d 35 of life) on serum corticosterone, performance variables, intestinal histology, and peritoneal macrophage activity in chickens. We demonstrated that the acute heat stress increased serum corticosterone concentrations and mortality and decreased food intake, BW gain, and feed conversion (P < 0.05). We did not find changes in the relative weights of the spleen, thymus, and bursa of Fabricius (P > 0.05). Increases in the basal and the Staphylococcus aureus-induced macrophage oxidative bursts and a decrease in the percentage of macrophages performing phagocytosis were also observed. Finally, mild, multifocal acute enteritis, characterized by the increased presence of lymphocytes and plasmocytes within the lamina propria of the jejunum, was also observed. We found that the stress-induced hypothalamic-pituitary-adrenal axis activation was responsible for the negative effects observed on chicken performance and immune function as well as for the changes in the intestinal mucosa. The data presented here corroborate with those presented in other studies in the field of neuroimmunomodulation and open new avenues for the improvement of broiler chicken welfare and production performance.

Macrophage Dectin-1 Expression Is Controlled by Leukotriene B-4 via a GM-CSF/PU.1 Axis

Pattern recognition receptors for fungi include dectin-1 and mannose receptor, and these mediate phagocytosis, as well as production of cytokines, reactive oxygen species, and the lipid mediator leukotriene B-4 (LTB4). The influence of G protein-coupled receptor ligands such as LTB4 on fungal pattern recognition receptor expression is unknown. In this study, we investigated the role of LTB4 signaling in dectin-1 expression and responsiveness in macrophages. Genetic and pharmacologic approaches showed that LTB4 production and signaling through its high-affinity G protein-coupled receptor leukotriene B4 receptor 1 (BLT1) direct dectin-1-dependent binding, ingestion, and cytokine production both in vitro and in vivo. Impaired responses to fungal glucans correlated with lower dectin-1 expression in macrophages from leukotriene (LT)- and BLT1-deficent mice than their wildtype counterparts. LTB4 increased the expression of the transcription factor responsible for dectin-1 expression, PU.1, and PU.1 small interfering RNA abolished LTB4-enhanced dectin-1 expression. GM-CSF controls PU.1 expression, and this cytokine was decreased in LT-deficient macrophages. Addition of GM-CSF to LT-deficient cells restored expression of dectin-1 and PU.1, as well as dectin-1 responsiveness. In addition, LTB4 effects on dectin-1, PU.1, and cytokine production were blunted in GM-CSF-/- macrophages. Our results identify LTB4-BLT1 signaling as an unrecognized controller of dectin-1 transcription via GM-CSF and PU.1 that is required for fungi-protective host responses. The Journal of Immunology, 2012, 189: 906-915.

Renal macrophage infiltration is associated with a poor outcome in IgA nephropathy

OBJECTIVES: The objectives of our study were as follows: 1) to analyze the prognostic value of macrophage infiltration in primary IgA nephropathy (IgAN) and 2) to study the relationship between macrophages and other factors associated with the development of renal fibrosis, including mast cells, TGF-beta 1, alpha-SMA and NF-kB. METHODS: We analyzed 62 patients who had been diagnosed with IgAN between 1987 and 2003. Immunohistochemical staining was performed with monoclonal antibodies against CD68 and mast cell tryptase and polyclonal antibodies against TGF-beta 1, alpha-SMA and NF-kB p65. We also used Southwestern histochemistry for the in situ detection of activated NF-kB. RESULTS: The infiltration of macrophages into the tubulointerstitial compartment correlated with unfavorable clinical and histological parameters, and a worse clinical course of IgAN was significantly associated with the number of tubulointerstitial macrophages. Kaplan-Meier curves demonstrated that increased macrophage infiltration was associated with decreased renal survival. Moreover, the presence of macrophages was associated with mast cells, tubulointerstitial alpha-SMA expression and NF-kB activation (IH and Southwestern histochemistry). In the multivariate analysis, the two parameters that correlated with macrophage infiltration, proteinuria and tubulointerstitial injury, were independently associated with an unfavorable clinical course. CONCLUSION: An increased number of macrophages in the tubulointerstitial area may serve as a predictive factor for poor prognosis in patients with IgAN, and these cells were also associated with the expression of pro-fibrotic factors.