73 research outputs found

    Gut Microbiota and Inflammatory Bowel Disease

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    Inflammatory bowel disease (IBD) is a chronic and relapsing inflammatory disorder that includes Crohn’s disease and ulcerative colitis. Ulcerative colitis involves the distal colon, proximal colon, and cecum and can lead to ulcerations and bleeding. Crohn’s disease appears as patched lesions in the gastrointestinal tract and inflammation, stenosis, or fistulas. IBD affects millions of people worldwide and has been associated with high morbidity and mortality. Our intestine is colonized by trillions of microorganisms (including bacteria, viruses, fungi, and protozoa), which constitutes the microbiota. Reduction of bacteria with anti-inflammatory capacities and increase of bacteria with inflammatory capacities are observed in patients with IBD when compared with healthy individuals. Microbial balance is needed for the development of a healthy gut and a symbiotic microbiota without problems. Any disturbance in that balance leads to dysbiosis and the host may become more susceptible to disease. Some alteration in the microbiome is protective or causative; thus, we selectively will review IBD disease, pathogenesis, and potential roles of some members of microbiota in IBD. In this chapter, we also explain the therapeutic approaches targeting microbiota (probiotics, prebiotics, postbiotics) and the relationship between gut microbiota imbalance, and how defects in this dysbiosis can lead to disease

    Solvent effects on structural and thermochemical properties of p53 tumor-suppressor gene: a molecular modeling approach in drug design

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    The p53 tumor-suppressor protein is a cellular phosphoprotein and a negative regulator of cell growth. Most p53 mutations occur in exons 5–8 within the DNA-binding domain. Therefore, p53 can potentially be targeted with novel drugs designed to bind to a mutation and restore its stability or wild-type conformation. For the current study, Hartree–Fock calculations were used to investigate the solvent-induced effects of five different solvent media (acetone, ethanol, methanol, dimethyl sulfoxide, and water) on the thermochemical parameters and relative energies, and on the multinuclear nuclear magnetic resonance shielding tensors of oxygen, nitrogen, and phosphorus nuclei, of GAT. To understand how the solvent affects the mutation region (the “hot spot”) of p53, the relative energies of GAT in selected solvent media were determined. Some biological evidence suggested the structural stabilities of hot spots of GAT have the optimum temperature and solvent type for mutation. All the authors’ findings are in accordance with common biological phenomena. Another important objective of this study was to compare the hydration Gibbs free energies of CUA and GAT in water using two different approaches where the solvent was treated as a continuum of the constant at different levels of Hartree–Fock theory. The Gibbs hydration energy values obtained in water with the polarized continuum model directly applied on the isolated CUA and GAT sequences were compared with those determined from the hydrated models with four, six, and eight water molecule clusters around the hot spots uracil and adenine. The clustered structures of water molecules around the hot spots of GAT (in DNA level) and CUA (in transcriptional level) were found to be energetically favored. The results of this study provide a reliable insight into the nature of mutation processes, which is of utmost importance for the study of biochemical structures, and provide a basis for drug design

    Induction Effects Of Bacteroides Fragilis Derived Outer Membrane Vesicles On Toll Like Receptor 2, Toll Like Receptor 4 Genes Expression And Cytokines Concentration In Human Intestinal Epithelial Cells

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    Objective Gastrointestinal (GI) tract, like other mucosal surface, is colonized with a microbial population known as gut microbiota. Outer membrane vesicles (OMVs) which are produced by gram negative bacteria could be sensed by Toll like receptors (TLRs). The interaction between gut microbiota and TLRs affects homeostasis and immune responses. In this study, we evaluated TLR2, TLR4 genes expression and cytokines concentration in Caco-2 cell line treated with Bacteroides fragilis (B. fragilis) and its OMVs. Materials And Methods In this experimental study, OMVs were extracted using sequential centrifugation and their physicochemical properties were evaluated as part of quality control assessment. Caco-2 cells were treated with B. fragilis and its OMVs (180 and 350 µg/ml). Quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) was performed to assess TLR2 and TLR4 mRNA expression levels. Pro-inflammatory (IFNᵧ) and anti-inflammatory (IL- 4 and IL-10) cytokines were evaluated by ELISA. Results B. fragilis significantly decreased TLR2 and slightly increased TLR4 mRNA levels in Caco-2 cell line. The TLR2 mRNA level was slightly increased at 180 and 350 µg/ml of OMVs. Conversely, the TLR4 mRNA level was decreased at 180 µg/ml of OMVs, while it was significantly increased at 350 µg/ml of OMVs. Furthermore, B. fragilis and its OMVs significantly increased and decreased IFNᵧ concentration, respectively. Anti-inflammatory cytokines were increased by B. fragilis and its OMVs. Conclusion B. fragilis and its OMVs have pivotal role in the cross talk between gut microbiota and the host especially in the modulation of the immune system. Based on the last studies on immunomodulatory effect of B. fragilis derived OMVs on immune cells and our results, we postulate that B. fragilis derived OMVs could be possible candidates for the reduction of immune responses

    Interaction between Clostridium species and microbiota to progress immune regulation

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    Gut microbiota can interact with the immune system through direct or indirect pathways. In the indirect pathway, gut microbiota produces metabolites such as short chain fatty acids (SCFAs), which may modulate the immune response. SCFAs reduce inflammation, repair intestinal barrier, and induce propagation of specific immune cells, e.g., T regulatory cells (Treg), which can suppress reactive cells such as macrophage and dendritic cells (DCs). As one of the most dominant members of microbiota, Clostridium produces SCFAs. As one of SCFA members, butyrate plays an important role in the modulation of immune cells. Through butyrate production, Clostridium helps to generate aryl hydrocarbon receptor (AhR). AhR interacts with many proteins inside the cytoplasm including Heat Shock Protein 90 (HSP 90), HSP 23, and chaperone. Activation of AhR leads to its translocation inside the nucleus and gene expression, which yields cell differentiation, energy metabolism, microbial defense, and immune cell propagation. Moreover, it may interact with other cells like B-cell and epithelial cell, which are responsible for modulation and maturation, respectively. AhR causes upregulation in the co-stimulatory marker in the DCs and interacts with nuclear factor KB (NF-kappa B) to modulate cell function. Butyrate induces Treg (iTreg) propagation and upregulates the Forkhead box p3 (FOXP3) as a special marker of Treg cell. It may also yield signaling through (3-protein coupled receptors (GPRs) which, in turn, facilitates polymorphonuclear (PMN) chemotaxis. The interaction between microbiota and non-immune cells, such as Paneth cells, leads to the secretion of antimicrobial substance, erection of barriers against bacterial pathogens, and regulation of microbiota composition via feedback effect. In addition, the components released from microbiota, such as peptidoglycan, reinforce the maturation of both the immune system and non-immune tissue development. Moreover, microbiota can directly activate the effector cells, e.g., macrophage, to secrete cytokines and propagate Treg cells

    Effect of Dexamethasone on Striatal Neurotransmissions in the Rats Subjected to Parkinson’s Disease Animal Model

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    Objective(s)The aim of this study was to evaluate the effects of dexamethasone on striatal dopaminergic, glutamatergic and gamma amino butyric acid (GABA) ergic neurotransmission in normal and parkinsonian rats.Materials and MethodsDexamethasone (0.15, 0.30, 0.60 and 0.8 mg/kg) was administered to normal or parkinsonian rats (i.p.) followed by the analysis of the striatal neurotransmitters concentrations. Additionally, the effect of dexamethasone on the damaged Substantia nigra pars compata (SNc) neurons has been investigated. ResultsDexamethasone resulted in decreased level of striatum glutamatergic-GABAergic and enhanced dopaminergic neurotransmission in normal and parkinsonian rats. In addition, acute treatment with dexamethasone did not improve the lesion at all. ConclusionThese findings suggest the new therapeutic mechanism of action for dexamethasone in Parkinson’s disease animal model

    T cell cytokine responses in peripheral blood mononuclear cells from patients with multidrug-resistant tuberculosis following stimulation with proteins purified from Mycobacterium tuberculosis MDR clinical isolates

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    AbstractObjectiveTuberculosis (TB) is a devastating disease that remains a major health threat worldwide. The appearance of Mycobacterium tuberculosis strains resistance to current antibiotics is a growing problem, both in the third world and in developed countries. Completion of genomic sequencing of M. tuberculosis provides a strong foundation for subsequent identification of proteins to aid the understanding of protein function and the discovery of new drug targets or a TB vaccine. This study employed a proteomics approach to identify proteins from antibiotic resistant M. tuberculosis isolates and compare them to drug-sensitive isolates to determine the role of T cells in multidrug-resistant (MDR)-TB patients against M. tuberculosis-purified proteins (Rv0147) as compared with healthy subjects.MethodsProteins were extracted by Triton X-114 detergent-phase separation and precipitated by adding saturated ammonium sulfate to the supernatant. Following isoelectric focusing, proteins were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Mass spectrometry was performed, and protein sequences were determined. Peripheral bloom mononuclear cells (PBMCs) were cultured, and autologous T cells were isolated from PBMCs by negative selection. Cells were subsequently cultured at 37°C in 5% CO2, followed by stimulation with 10μg/mL of the protein candidate (Rv0147) for 72h. Culture supernatants were assayed for interleukin (IL)-10 and interferon (IFN)-γ by enzyme-linked immunosorbent assay.ResultsThe identified proteins included Rv3057c, Rv0009, Rv3161c, Rv3614c, Rv0685, Rv2986c, Rv0443, Rv2114, Rv3311, Rv0831, Rv3804, and Rv3614c, and our results showed that the majority of upregulated or overexpressed proteins belonged to pathways associated with cellular metabolism, cell wall integrity, respiration, or cell membrane construction. Additionally, Rv1876 from MDR-TB isolates was predicted to be involved in the expression of bacterioferritin exclusively in MDR-TB-related resistance to first-line TB drugs. Furthermore, Rv2031c (HspX) was induced under oxygen-deficient conditions, and hypothetical protein (Rv2744c) and two membrane- and cell-wall-fraction proteins (Rv0379 and Rv1886c) were also identified. Analysis revealed increased percentages of INF-γ and decreased IL-10 levels in MDR-TB patients as compared with those observed in normal subjects.ConclusionFour identified membrane or membrane-associated proteins, including bacterioferritin, GroEs, HspX, and Ef-Tu, may be potential targets for the development of novel prophylactic diagnostics and therapeutic strategies against TB. Our results suggested that T cells stimulated by the protein candidate Rv0147 may be shifted to T helper 1 status in MDR-TB patients

    Synthesis and characterization of a novel chemically designed (Globo)3–DTPA–KLH antigen

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    In recent years, many experiments have been conducted for the production and evaluation of anticancer glycoconjugated vaccines in developed countries and many achievements have been accomplished with Globo H derivatives. In the current experiment, a new chemically designed triplicate version of (Globo H)3–diethylenetriamine pentaacetic acid (DTPA)–KLH antigen was synthesized and characterized. Immunization with (Globo H)3-DTPA-KLH, a hexasaccharide that is a member of a family of antigenic carbohydrates that are highly expressed in various types of cancers conjugated with DTPA and KLH protein, induced a high level of antibody titer along with an elevated level of IL-4 in mice. Treatment of tumors with the collected sera from immunized mice decreased the tumor size in nude mice as well. None of the immunized mice illustrated any sign of tumor growth after injection of MCF-7 cells compared to the control animals. These findings, based on the newly presented structure of the Globo H antigen, lend exciting and promising evidence for clinical advancement in the development of a therapeutic vaccine in the future
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