Lack of galectin-3 up-regulates IgA expression by peritoneal B1 lymphocytes during B cell differentiation.

Galectin-3 is a ß-galactoside-binding protein with an inhibitory role in B cell differentiation into plasma cells in distinct lymphoid tissues. We use a model of chronic schistosomiasis, a well-characterized experimental disease hallmarked by polyclonal B cell activation, in order to investigate the role of galectin-3 in controlling IgA production through peritoneal B1 cells. Chronically infected, galectin-3-deficient mice (Lgals3(-/-)) display peritoneal fluid hypercellularity, increased numbers of atypical peritoneal IgM(+)/IgA(+) B1a and B1b lymphocytes and histological disturbances in plasma cell niches when compared with Lgals3(+/+) mice. Similar to our infection model, peritoneal B1 cells from uninfected Lgals3(-/-) mice show enhanced switching to IgA after in vitro treatment with interleukin-5 plus transforming growth factor-ß (IL-5 + TGF-ß1). A higher number of IgA(+) B1a lymphocytes was found in the peritoneal cavity of Lgals3(-/-)-uninfected mice at 1 week after i.p. injection of IL-5 + TGF-ß1; this correlates with the increased levels of secreted IgA detected in the peritoneal fluid of these mice after cytokine treatment. Interestingly, a higher number of degranulated mast cells is present in the peritoneal cavity of uninfected and Schistosoma mansoni-infected Lgals3(-/-) mice, indicating that, at least in part, mast cells account for the enhanced differentiation of B1 into IgA-producing B cells found in the absence of galectin-3. Thus, a novel role is revealed for galectin-3 in controlling the expression of surface IgA by peritoneal B1 lymphocytes; this might have important implications for manipulating the mucosal immune response.

Differential development of oil granulomas induced by pristane injection in galectin-3 deficient mice.

BACKGROUND: Galectin-3 is known to be a lectin that plays an important role in inflammatory processes, acting as pro-inflammatory mediator in activation and migration of neutrophils and macrophages, as well as in the phagocytic function of these cells. The injection of mineral oils into the peritoneal cavity of mice, such as 2, 6, 10, 14-tetramethylpentadecane (pristane), induce a chronic granulomatous inflammatory reaction which is rich in macrophages, B cells and peritoneal plasma cells known as oil granuloma. In addition, this inflammatory microenvironment provided by oil granulomas is also an important site of plasmacytoma induction, which are dependent on cytokine production and cellular mobilization. Here, we have analyzed the role of galectin-3 in inflammatory cells mobilization and organization after pristane injection characterizing granulomatous reaction through the formation of oil granulomas. RESULTS: In galectin-3 deficient mice (gal-3(-/-)), the mobilization of inflammatory cells, between peritoneal cavity and bone marrow, was responsible for the formation of disorganized oil granulomas, which presented scattered cells, large necrotic areas and low amounts of extracellular matrix. The production of inflammatory cytokines partially explained the distribution of cells through peritoneal cavity, since high levels of IL-6 in gal-3(-/-) mice led to drastically reduction of B1 cells. The previous pro-inflammatory status of these animals also explains the excess of cell death and disruption of oil granulomas architecture. CONCLUSIONS: Our data indicate, for the first time, that the disruption in the inflammatory cells migration in the absence of galectin-3 is a crucial event in the formation and organization of oil granulomas.

Effects of caffeic and 5-caffeoylquinic acids on cell viability and cellular uptake in human colon adenocarcinoma cells.

Colorectal cancer is a major cause of morbidity and mortality throughout the world. Issues related to the role of diet in cancer prevention and treatment are featured each year, and, in this context, consumption of hydroxycinanmic acids is associated with reduced risk of chronic diseases including cancer. Therefore, the aim of this study was to evaluate the cellular uptake of caffeic and 5-caffeoylquinic acids and their effects on cell viability, cell cycle, and apoptosis in human colon adenocarcinoma cells (HT-29). HT-29 cells were incubated with different concentrations of caffeic and 5-caffeoylquinic acids (1.25 µM to 80.0 µM) from 0.5 to 96 h. Cellular uptake was analyzed by HPLC and LCMS. Cell viability, cell cycle, and apoptosis was measured, respectively, using MTT method and flow cytometry. Caffeic and 5-caffeoylquinic acids are absorbed, isomerized, and metabolized by HT-29 cells. Both compounds were able to reduce HT-29 cell viability, promoting specific changes in the cell cycle and increased the apoptosis rate. Caffeic acid and 5-caffeoylquinic acid showed inhibitory effects on cell growth, suggesting a modulation of the cell cycle with an increase in apoptosis in human colon adenocarcinoma cells.

Lack of galectin-3 modifies differentially Notch ligands in bone marrow and spleen stromal cells interfering with B cell differentiation.

Galectin-3 (Gal-3) is a ß-galactoside binding protein that controls cell-cell and cell-extracellular matrix interactions. In lymphoid organs, gal-3 inhibits B cell differentiation by mechanisms poorly understood. The B cell development is dependent on tissue organization and stromal cell signaling, including IL-7 and Notch pathways. Here, we investigate possible mechanisms that gal-3 interferes during B lymphocyte differentiation in the bone marrow (BM) and spleen. The BM of gal-3-deficient mice (Lgals3-/- mice) was evidenced by elevated numbers of B220+CD19+c-Kit+IL-7R+ progenitor B cells. In parallel, CD45- bone marrow stromal cells expressed high levels of mRNA IL-7, Notch ligands (Jagged-1 and Delta-like 4), and transcription factors (Hes-1, Hey-1, Hey-2 and Hey-L). The spleen of Lgals3-/- mice was hallmarked by marginal zone disorganization, high number of IgM+IgD+ B cells and CD138+ plasma cells, overexpression of Notch ligands (Jagged-1, Delta-like 1 and Delta-like 4) by stromal cells and Hey-1. Morever, IgM+IgD+ B cells and B220+CD138+ CXCR4+ plasmablasts were significantly increased in the BM and blood of Lgals3-/- mice. For the first time, we demonstrated that gal-3 inhibits Notch signaling activation in lymphoid organs regulating earlier and terminal events of B cell differentiation.

Os impactos da neuroinflamação na doença de Alzheimer / The impacts of neuroinflamation on Alzheimer's disease

A Doença de Alzheimer (DA) consiste em um grande problema de saúde pública no Brasil e no mundo. Trata-se de uma doença neurodegenerativa, em que ocorre perda progressiva de neurônios e atrofia das regiões cerebrais. Essa degeneração está associada principalmente ao depósito de duas proteínas tóxicas: a proteína beta-amiloide e a proteína Tau, uma vez que estas proteínas se encontram acumuladas, elas prejudicam a ocorrência de sinapses nervosas. Apesar de extremamente prevalente na população mais idosa, suas causas ainda não estão bem esclarecidas, sendo que vários fatores já foram apontados como possíveis motivos para o surgimento do depósito destas proteínas, levando assim a neurodegeneração. Recentemente, tem se estudado o papel da inflamação, que é fundamental durante todo o curso da doença, tanto para a eliminação das proteínas tóxicas quanto para a proteção de neurônios. Um funcionamento anormal do processo inflamatório poderia dificultar a eliminação das proteínas e acentuar a perda neuronal. Com isso essa revisão de literatura tem como objetivo descrever os principais fatores imunológico que se encontram alterados na Doença de Alzheimer e como isso pode contribuir para o quadro neurodegenerativo.

Alzheimer's Disease (AD) is a major public health problem in Brazil and worldwide. It is a neurodegenerative disease, in which there is a progressive loss of neurons and atrophy of brain regions. This degeneration is mainly associated with the deposition of two toxic proteins, the beta-amyloid protein and the Tau protein, once these proteins are accumulated, they impair the occurrence of nerve synapses. Despite being extremely prevalent in the older population, its causes are still not well understood, and several factors have already been pointed out as possible reasons for the emergence of the deposit of these proteins, thus leading to neurodegeneration. Recently, the role of inflammation, which is fundamental throughout the course of the disease, has been studied, both for the elimination of toxic proteins and for the protection of neurons. An abnormal functioning of the inflammatory process could hinder the elimination of proteins and accentuate the neuronal loss Thus, this literature review aims to describe the main immunological factors that are altered in Alzheimer's Disease and how this can contribute to the neurodegenerative picture.

Hepatic myofibroblasts derived from Schistosoma mansoni-infected mice are a source of IL-5 and eotaxin: controls of eosinophil populations in vitro.

BACKGROUND: Hepatic myofibroblasts are relevant for pathogenesis of S. mansoni infection. In normal liver, these perisinusoidal cells are quiescent, express the lipocyte phenotype, and are located in the Disse's space, being the major site of vitamin A storage. When activated, they convert to myofibroblasts and contribute to granulomatous and diffuse liver fibrosis. In the present work, we observed that myofibroblasts obtained from granulomatous periovular inflammatory reactions in schistosome-infected mice (GR-MF) produce in vitro immunomodulatory cytokines for eosinophil activation: IL-5 and eotaxin. METHODS AND RESULTS: The secretory activity of GR-MF was detected after TGF-ß and IL-13 stimulation using 2D and 3D cell culture systems. In a mixed co-culture system using GR-MF with hematopoietic bone marrow cells from infected mice, we observed eosinophil survival that was dependent upon IL-5 and eotaxin, since antibodies against this cytokines decreased eosinophil population, as measured by eosinophil peroxidase activity. CONCLUSION: These results indicate that GR-MF may contribute to maintenance of local eosinophilia in schistosomal hepatic granulomas, and can function as immunoregulatory cells, besides their role in production of fibrosis.

Epigenetic Control of Macrophage Shape Transition towards an Atypical Elongated Phenotype by Histone Deacetylase Activity.

Inflammatory chronic pathologies are complex processes characterized by an imbalance between the resolution of the inflammatory phase and the establishment of tissue repair. The main players in these inflammatory pathologies are bone marrow derived monocytes (BMDMs). However, how monocyte differentiation is modulated to give rise to specific macrophage subpopulations (M1 or M2) that may either maintain the chronic inflammatory process or lead to wound healing is still unclear. Considering that inhibitors of Histone Deacetylase (HDAC) have an anti-inflammatory activity, we asked whether this enzyme would play a role on monocyte differentiation into M1 or M2 phenotype and in the cell shape transition that follows. We then induced murine bone marrow progenitors into monocyte/macrophage differentiation pathway using media containing GM-CSF and the HDAC blocker, Trichostatin A (TSA). We found that the pharmacological inhibition of HDAC activity led to a shape transition from the typical macrophage pancake-like shape into an elongated morphology, which was correlated to a mixed M1/M2 profile of cytokine and chemokine secretion. Our results present, for the first time, that HDAC activity acts as a regulator of macrophage differentiation in the absence of lymphocyte stimuli. We propose that HDAC activity down regulates macrophage plasticity favoring the pro-inflammatory phenotype.

Lycopene and beta-carotene induce cell-cycle arrest and apoptosis in human breast cancer cell lines.

Lycopene and beta-carotene are carotenoids widely distributed in fruits and vegetables, with potential anticancer activity. Epidemiological trials rarely provide evidence for the mechanisms of action of these compounds, and their biological effects at different times of treatment are still unclear. The aim of the present study was to determine the effect of carotenoids on the cell cycle and cell viability in human breast cancer cell lines. Human breast cell lines were treated with carotenoids (0.5-10 µM) for 48 and 96 h. Cell viability was monitored using the MTT method (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide; thiazolyl blue). The cell cycle was analyzed by flow cytometry, and apoptotic cells were identified by annexin/propidium iodide (PI) biomarkers. Our data showed a significant decrease in the number of viable breast cancer cells on treatment with carotenoids. Carotenoids also promoted cell-cycle arrest followed by decreased cell viability in the majority of cell lines after 96 h, compared to controls. Furthermore, an increase in apoptosis was observed in cell lines when cells were treated with carotenoids. Our findings show the capacity of lycopene and beta-carotene to inhibit cell proliferation, arrest the cell cycle in different phases, and increase apoptosis. These findings indicate that the effect was cell type-dependent and that carotenoids are potential agents for biological interference with cancer.

The involvement of the spleen during chronic phase of Schistosoma mansoni infection in galectin-3-/- mice.

Schistosoma mansoni synthesizes glycoconjugates which interact with galectin-3, eliciting an intense humoral immune response. Moreover, it was demonstrated that galectin-3 regulates B cell differentiation into plasma cells. Splenomegaly is a hallmark event characterized by polyclonal B cell activation and enhancement of antibody production. Here, we investigated whether galectin-3 interferes with spleen organization and B cell compartment during chronic schistosomiasis, using wild type (WT) and galectin-3-/- mice. In chronically-infected galectin-3-/- mice the histological architecture of the spleen, including white and red pulps, was disturbed with heterogeneous lymphoid follicles, an increased number of plasma cells (CD19-B220-/lowCD138+) and a reduced number of macrophages (CD19-B220-Mac-1+CD138-) and B lymphocytes (CD19+B220+/highCD138-), compared with the WT infected mice. In the absence of galectin-3 there was an increase of annexin-V+PI- cells and a major presence of apoptotic cells in spleen compared with WT infected mice. In spleen of WT infected mice galectin-3 was largely expressed in lymphoid follicles and extrafollicular sites. Thus, we propose that galectin-3 plays a role in splenic architecture, controlling distinct events such as apoptosis, macrophage activity, B cell differentiation and plasmacytogenesis in the course of S. mansoni infection.

Lack of galectin-3 disturbs mesenteric lymph node homeostasis and B cell niches in the course of Schistosoma mansoni infection.

Galectin-3 is a ß-galactoside-binding protein that has been shown to regulate pathophysiological processes, including cellular activation, differentiation and apoptosis. Recently, we showed that galectin-3 acts as a potent inhibitor of B cell differentiation into plasma cells. Here, we have investigated whether galectin-3 interferes with the lymphoid organization of B cell compartments in mesenteric lymph nodes (MLNs) during chronic schistosomiasis, using WT and galectin-3(-/-) mice. Schistosoma mansoni synthesizes GalNAcß1-4(Fucα1-3)GlcNAc(Lac-DiNAc) structures (N-acetylgalactosamine ß1-4 N-acetylglucosamine), which are known to interact with galectin-3 and elicit an intense humoral response. Antigens derived from the eggs and adult worms are continuously drained to MLNs and induce a polyclonal B cell activation. In the present work, we observed that chronically-infected galectin-3(-/-) mice exhibited a significant reduced amount of macrophages and B lymphocytes followed by drastic histological changes in B lymphocyte and plasma cell niches in the MLNs. The lack of galectin-3 favored an increase in the lymphoid follicle number, but made follicular cells more susceptible to apoptotic stimuli. There were an excessive quantity of apoptotic bodies, higher number of annexin V(+)/PI(-) cells, and reduced clearance of follicular apoptotic cells in the course of schistosomiasis. Here, we observed that galectin-3 was expressed in non-lymphoid follicular cells and its absence was associated with severe damage to tissue architecture. Thus, we convey new information on the role of galectin-3 in regulation of histological events associated with B lymphocyte and plasma cell niches, apoptosis, phagocytosis and cell cycle properties in the MLNs of mice challenged with S.mansoni.