Search

Colorectal cancer (CRC) is one of the most common cancers worldwide. As with other cancers, CRC is a multifactorial disease due to the combined effect of genetic and environmental factors. Most cases are sporadic, but a small proportion is hereditary, estimated at around 5-10%. In both, the tumor interacts with heterogeneous cell populations, such as endothelial, stromal, and immune cells, secreting different signals (cytokines, chemokines or growth factors) to generate a favorable tumor microenvironment for cancer cell invasion and metastasis. There is ample evidence that inflammatory processes have a role in carcinogenesis and tumor progression in CCR. Different profiles of cell activation of the tumor microenvironment can promote pro or anti-tumor pathways; hence they are studied as a key target for the control of cancer progression. Additionally, the intestinal mucosa is in close contact with a microorganism community, including bacteria, bacteriophages, viruses, archaea, and fungi composing the gut microbiota. Aberrant composition of this microbiota, together with alteration in the diet‐derived microbial metabolites content (such as butyrate and polyamines) and environmental compounds has been related to CRC. Some bacteria, such as pks+ Escherichia coli or Fusobacterium nucleatum, are involved in colorectal carcinogenesis through different pathomechanisms including the induction of genetic mutations in epithelial cells and modulation of tumor microenvironment. Epithelial and immune cells from intestinal mucosa have Pattern-recognition receptors and G-protein coupled receptors (receptor of butyrate), suggesting that their activation can be regulated by intestinal microbiota and metabolites. In this review, we discuss how dynamics in the gut microbiota, their metabolites, and tumor microenvironment interplays in sporadic and hereditary CRC, modulating tumor progression.

In colorectal cancer (CRC), cancer-associated fibroblasts (CAFs) are the most abundant component from the tumor microenvironment (TM). CAFs facilitate tumor progression by inducing angiogenesis, immune suppression and invasion, thus altering the organization/composition of the extracellular matrix (i.e., desmoplasia) and/or activating epithelial-mesenchymal transition (EMT). Soluble factors from the TM can also contribute to cell invasion through secretion of cytokines and recently, IL-33/ST2 pathway has gained huge interest as a protumor alarmin, promoting progression to metastasis by inducing changes in TM. Hence, we analyzed IL-33 and ST2 content in tumor and healthy tissue lysates and plasma from CRC patients. Tissue localization and distribution of these molecules was evaluated by immunohistochemistry (using localization reference markers α-smooth muscle actin or α-SMA and E-cadherin), and clinical/histopathological information was obtained from CRC patients. In vitro experiments were conducted in primary cultures of CAFs and normal fibroblasts (NFs) isolated from tumor and healthy tissue taken from CRC patients. Additionally, migration and proliferation analysis were performed in HT29 and HCT116 cell lines. It was found that IL-33 content increases in left-sided CRC patients with lymphatic metastasis, with localization in tumor epithelia associated with abundant desmoplasia. Although ST2 content showed similarities between tumor and healthy tissue, a decreased immunoreactivity was observed in left-sided tumor stroma, associated to metastasis related factors (advanced stages, abundant desmoplasia, and presence of tumor budding). A principal component analysis (including stromal and epithelial IL-33/ST2 and α-SMA immunoreactivity with extent of desmoplasia) allowed us to distinguish clusters of low, intermediate and abundant desmoplasia, with potential to develop a diagnostic signature with benefits for further therapeutic targets. IL-33 transcript levels from CAFs directly correlated with CRC cell line migration induced by CAFs conditioned media, with rhIL-33 inducing a mesenchymal phenotype in HT29 cells. These results indicate a role of IL-33/ST2 in tumor microenvironment, specifically in the interaction between CAFs and epithelial tumor cells, thus contributing to invasion and metastasis in left-sided CRC, most likely by activating desmoplasia.

Ulcerative colitis (UC) and Crohn's disease (CD), collectively known as Inflammatory Bowel Diseases (IBD), are caused by a complex interplay between genetic, immunologic, microbial and environmental factors. Dysbiosis of the gut microbiome is increasingly considered to be causatively related to IBD and is strongly affected by components of a Western life style. Bacteria that ferment fibers and produce short chain fatty acids (SCFAs) are typically reduced in mucosa and feces of patients with IBD, as compared to healthy individuals. SCFAs, such as acetate, propionate and butyrate, are important metabolites in maintaining intestinal homeostasis. Several studies have indeed shown that fecal SCFAs levels are reduced in active IBD. SCFAs are an important fuel for intestinal epithelial cells and are known to strengthen the gut barrier function. Recent findings, however, show that SCFAs, and in particular butyrate, also have important immunomodulatory functions. Absorption of SCFAs is facilitated by substrate transporters like MCT1 and SMCT1 to promote cellular metabolism. Moreover, SCFAs may signal through cell surface G-protein coupled receptors (GPCRs), like GPR41, GPR43, and GPR109A, to activate signaling cascades that control immune functions. Transgenic mouse models support the key role of these GPCRs in controlling intestinal inflammation. Here, we present an overview of microbial SCFAs production and their effects on the intestinal mucosa with specific emphasis on their relevance for IBD. Moreover, we discuss the therapeutic potential of SCFAs for IBD, either applied directly or by stimulating SCFAs-producing bacteria through pre- or probiotic approaches.

Crohn’s disease (CD) is a chronic inflammatory bowel disorder characterized by deregulated inflammation triggered by environmental factors. Notably, adherent-invasive Escherichia coli (AIEC), a bacterium with the ability to survive within macrophages is believed to be one of such factors. Glucocorticoids are the first line treatment for CD and to date, it is unknown how they affect bactericidal and inflammatory properties of macrophages against AIEC. The aim of this study was to evaluate the impact of glucocorticoid treatment on AIEC infected macrophages. First, THP-1 cell-derived macrophages were infected with a CD2-a AIEC strain, in the presence or absence of the glucocorticoid dexamethasone (Dex) and mRNA microarray analysis was performed. Differentially expressed mRNAs were confirmed by TaqMan-qPCR. In addition, an amikacin protection assay was used to evaluate the phagocytic and bactericidal activity of Dex-treated macrophages infected with E. coli strains (CD2-a, HM605, NRG857c, and HB101). Finally, cytokine secretion and the inflammatory phenotype of macrophages were evaluated by ELISA and flow cytometry, respectively. The microarray analysis showed that CD2-a, Dex, and CD2-a + Dex-treated macrophages have differential inflammatory gene profiles. Also, canonical pathway analysis revealed decreased phagocytosis signaling by Dex and anti-inflammatory polarization on CD2-a + Dex macrophages. Moreover, amikacin protection assay showed reduced phagocytosis upon Dex treatment and TaqMan-qPCR confirmed Dex inhibition of three phagocytosis-associated genes. All bacteria strains induced TNF-α, IL-6, IL-23, CD40, and CD80, which was inhibited by Dex. Thus, our data demonstrate that glucocorticoids impair phagocytosis and induce anti-inflammatory polarization after AIEC infection, possibly contributing to the survival of AIEC in infected CD patients.

CD28 and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) are two receptors that have complementary functions in control of T-cell activation. Polymorphisms of their genes, CD28 and CTLA4, might confer differential susceptibility to diseases resulting from unbalanced or inefficient immune responses. Thus far, little is known about the CD28 polymorphism in populations and even for CTLA4 just one or two single nucleotide polymorphisms (SNPs) are usually analysed. To assess the allelic and haplotypic diversity and linkage disequilibrium in the Brazilian population, two samples differing according to predominant ancestry - African or European - have been analysed for seven SNPs, CD28 -372(G>A), and int3 17(T>C); CTLA4 -1722(T>C), -1577(G>A) -318(C>T), 49(A>G), 6230(G>A) also named CT60, and three microsatellites, CD28 (CAA)n, CTLA4 (AT)n and D2S72 (CA)n. The two population strata show little differentiation, the only significant differences being the allele frequencies of the CTLA4 -1577(G>A) SNP and the CTLA4 (AT)n microsatellite (P = 0.018 and P = 0.007, respectively). Linkage disequilibrium is high, especially between the CTLA4 polymorphisms. However, low r(2) values indicate that none of the markers is a tag SNP in these populations. These results provide valuable information for optimal selection of markers for use in future association studies. We conclude that disease association studies and functional studies addressing the possible consequences of polymorphisms of the 2q33 genomic region should consider haplotypic data besides analysis of individual polymorphisms.

The purpose of this study was to analyze the possible influence of the TNF and LTA loci polymorphisms on the susceptibility/resistance to endemic pemphigus foliaceus, also named fogo selvagem (FS), an autoimmune disease characterized by blisters due to acantholysis of the superficial-most epidermal cells. Autoantibodies, mainly of the IgG4 subclass, are directed against a desmosomal glycoprotein known as desmoglein 1. FS shares clinical, histological and immunological features with nonendemic pemphigus foliaceus. Most residents of the endemic regions do not develop the disease, and familial clustering has been documented, suggesting that host factors play a role in susceptibility. In fact, strong positive and negative associations with HLA class II genes have been reported. The TNF and LTA genes are located in the class III region of the Human Major Histocompatibility Complex. Their location, the function of their products, which are cytokines and pluripotent immunomodulators, as well as their genetic variability make them candidate genes for complex diseases with an altered immune response. A total of 162 patients and 191 controls were enrolled in this study. No significant associations were found with any one of the three LTA single nucleotide polymorphisms (SNP) analyzed (at nucleotides 249, 365, 720), nor with the TNF SNP located at positions −863 and −308. The frequency of allele TNF*238A was slightly decreased in patients (OR = 0.45). In conclusion, the results of this study indicate that genetic variability of the TNF and LTA genes does not play a major role in susceptibility/resistance to pemphigus foliaceus.

Endemic pemphigus foliaceus (EPF) is a blistering skin disease characterized by autoantibodies against the desmosomal protein desmoglein 1. Genetic and environmental factors influence its pathogenesis. A total of 128 patients and 402 controls from an ethnically admixed Brazilian population were analyzed for associations by allele and genotype with HLA-DRB1. The alleles DRB1(*)0101, (*)0102, (*)0103, (*)0404, (*)0406, (*)0410, (*)1406 and (*)1601 are significantly more frequent among patients, while DRB1(*)0301, (*)0701, (*)0801, (*)1101, (*)1104 and (*)1402 are negatively associated to EPF. Results of association analysis with protein motifs composed of polymorphic amino-acid residues do not add much to comprehension of the molecular basis of the HLA-DRB1/EPF associations. Interactions between susceptible (SU), protective (PR) and neutral (NE) alleles clearly deviate from the codominant model. Protection is dominant, since the PR/NE and PR/PR genotypes are both equally (P=0.95) and strongly protective (odds ratio OR=0.07 and 0.05, respectively; P

Endemic pemphigus foliaceus (EPF) is an autoimmune bullous skin disease characterized by acantholysis and antibodies against a desmosomal protein, desmoglein 1. Genetic and environmental factors contribute to development of this multifactorial disease. HLA class II and some cytokine gene polymorphisms are the only genetic markers thus far known to be associated with susceptibility to or protection from EPF. The cytotoxic T-lymphocyte antigen-4 gene (CTLA4) encodes a key immunoreceptor molecule that regulates and inhibits T-cell proliferation. It participates in the regulatory process controlling autoreactivity and therefore has been considered a strong candidate gene in autoimmune diseases. In the search for genes that might influence EPF pathogenesis, we analyzed variants of the CTLA4 gene in a sample of 118 patients and 291 controls from a Brazilian population. This is the first study investigating the possible role of polymorphisms of the 2q33 chromosomal region in differential susceptibility to pemphigus foliaceus. Promoter region and exon 1 single nucleotide polymorphisms -318 (C,T) and 49 (A,G) were genotyped using sequence-specific oligonucleotide probes after amplification by the polymerase chain reaction. The allelic and genotypic frequencies did not differ significantly between the patient and the control groups (-318T: 9.8 and 10.9%, 49G: 33.0 and 35.2% were the allelic frequencies in patients and controls, respectively). In addition, no significant difference was found when the patient and control population samples were stratified by the presence of HLA-DRB1 alleles. We conclude that the CTLA4 -318 (C,T) and 49 (A,G) polymorphisms do not play a major role in EPF development.

The aim of the present study was to investigate a broad spectrum of autoantibodies in patients with endemic pemphigus foliaceus (EPF)—fogo selvagem—and to determine the possible association between EPF and other autoimmune diseases. Indirect immunofluorescence was used to test 120 patients with EPF and 200 healthy controls for the presence of the following autoantibodies: anti-desmoglein-1 (APF), anti-neutrophil cytoplasmic (ANCA), anti-smooth muscle (SMA), anti-mitochondrial (AMA), anti-nuclear (ANA), anti-liver kidney microsomal (LKM), anti-gastric parietal cells (GPCA) and anti-thyroid microsome (TMA). APF antibodies were detected in 62.5% of the patients (75/120), ANA and SMA in 0.8% (1/120), and TMA in 1.6% (2/120). None of the patients was positive for ANCA, AMA, LKM or GPCA. In the control group, a positivity of 2% was observed for SMA (4/200), 1.5% for TMA (3/200), and 0.5% (1/200) for ANA and GPCA. None of the controls was positive for APF, LKM, AMA or ANCA. The prevalence of the autoantibodies ANA, SMA, AMA, GPCA, LKM and ANCA in patients with EPF was similar to that observed in the control group. No association with clinical or laboratory manifestations of other concomitant autoimmune diseases was observed in EPF patients. These results confirm the concept that EPF is an organ-specific autoimmune disease.

Chagas' disease, caused by the hemoflagellate protozoan Trypanosoma cruzi , affects millions of people in South and Central America. Chronic chagasic cardiomyopathy, the most devastating manifestation of this disease, occurs in approximately one-third of infected individuals. Events associated with the parasite's tropism for and invasion of cardiomyocytes have been the focus of intense investigation in recent years. In the present study, we use murine microarrays to investigate the cellular response caused by invasion of primary murine cardiomyocytes by T. cruzi trypomastigotes. These studies identified 353 murine genes that were differentially expressed during the early stages of invasion and infection of these cells. Genes associated with the immune response, inflammation, cytoskeleton organization, cell-cell and cell-matrix interactions, apoptosis, cell cycle, and oxidative stress are among those affected during the infection. Our data indicate that T. cruzi induces broad modulations of the host cell machinery in ways that provide insight into how the parasite survives, replicates, and persists in the infected host and ultimately defines the clinical outcome of the infection.

Dengue virus (DENV) infection can cause a self-limiting disease (dengue fever) or a more severe clinical presentation known as dengue hemorrhagic fever (DHF)/dengue shock syndrome (DSS). Furthermore, data from recent dengue epidemics in Brazil indicate that the neurological manifestations are becoming more prevalent. However, the neuropathogenesis of dengue are not well understood. The balance between viral replication efficiency and innate immunity — in opposition during the early stages of infection — determines the clinical outcome of DENV infection. In this study, we investigated the effects of DENV infection on the transcription profile of the central nervous system (CNS) of mice. We observed in infected mice the up-regulation of 151 genes possibly involved in neuropathogenesis of dengue. Conversely, they may have a protective effect. Ingenuity Systems software analysis demonstrated, that the main pathways modulated by DENV infection in the mouse CNS are involved in interferon signaling and antigen presentation.