Browsing by Author "Guri, Amir J."

Now showing 1 - 9 of 9
  • Thumbnail Image
    Dietary alpha-Eleostearic Acid Ameliorates Experimental Inflammatory Bowel Disease in Mice by Activating Peroxisome Proliferator-Activated Receptor-gamma
    Lewis, Stephanie N.; Brannan, Lera; Guri, Amir J.; Lu, Pinyi; Hontecillas, Raquel; Bassaganya-Riera, Josep; Bevan, David R. (PLOS, 2011-08-31)
    Background: Treatments for inflammatory bowel disease (IBD) are modestly effective and associated with side effects from prolonged use. As there is no known cure for IBD, alternative therapeutic options are needed. Peroxisome proliferator-activated receptor-gamma (PPARγ) has been identified as a potential target for novel therapeutics against IBD. For this project, compounds were screened to identify naturally occurring PPARγ agonists as a means to identify novel anti-inflammatory therapeutics for experimental assessment of efficacy. Methodology/Principal Findings: Here we provide complementary computational and experimental methods to efficiently screen for PPARγ agonists and demonstrate amelioration of experimental IBD in mice, respectively. Computational docking as part of virtual screening (VS) was used to test binding between a total of eighty-one compounds and PPARγ. The test compounds included known agonists, known inactive compounds, derivatives and stereoisomers of known agonists with unknown activity, and conjugated trienes. The compound identified through VS as possessing the most favorable docked pose was used as the test compound for experimental work. With our combined methods, we have identified α-eleostearic acid (ESA) as a natural PPARγ agonist. Results of ligand-binding assays complemented the screening prediction. In addition, ESA decreased macrophage infiltration and significantly impeded the progression of IBD-related phenotypes through both PPARγ-dependent and –independent mechanisms in mice with experimental IBD. Conclusions/Significance: This study serves as the first significant step toward a large-scale VS protocol for natural PPARγ agonist screening that includes a massively diverse ligand library and structures that represent multiple known target pharmacophores.
  • Thumbnail Image
    Helicobacter pylori Colonization Ameliorates Glucose Homeostasis in Mice through a PPAR γ-Dependent Mechanism
    Bassaganya-Riera, Josep; Dominguez-Bello, Maria Gloria; Kronsteiner, Barbara; Carbo, Adria; Pinyi, Lu; Viladomiu, Monica; Pedragosa, Mireia; Zhang, Xiaoying; Sobral, Bruno; Mane, Shrinivasrao P.; Mohapatra, Saroj K.; Horne, William T.; Guri, Amir J.; Groeschl, Michael; Lopez-Velasco, Gabriela; Hontecillas, Raquel (Public Library of Science, 2012-11-15)
    Background: There is an inverse secular trend between the incidence of obesity and gastric colonization with Helicobacter pylori, a bacterium that can affect the secretion of gastric hormones that relate to energy homeostasis. H. pylori strains that carry the cag pathogenicity island (PAI) interact more intimately with gastric epithelial cells and trigger more extensive host responses than cag− strains. We hypothesized that gastric colonization with H. pylori strains differing in cag PAI status exert distinct effects on metabolic and inflammatory phenotypes. Methodology/Principal Findings: To test this hypothesis, we examined metabolic and inflammatory markers in db/db mice and mice with diet-induced obesity experimentally infected with isogenic forms of H. pylori strain 26695: the cag PAI wild-type and its cag PAI mutant strain 99–305. H. pylori colonization decreased fasting blood glucose levels, increased levels of leptin, improved glucose tolerance, and suppressed weight gain. A response found in both wild-type and mutant H. pylori strain-infected mice included decreased white adipose tissue macrophages (ATM) and increased adipose tissue regulatory T cells (Treg) cells. Gene expression analyses demonstrated upregulation of gastric PPAR γ-responsive genes (i.e., CD36 and FABP4) in H. pylori-infected mice. The loss of PPAR γ in immune and epithelial cells in mice impaired the ability of H. pylori to favorably modulate glucose homeostasis and ATM infiltration during high fat feeding. Conclusions/Significance: Gastric infection with some commensal strains of H. pylori ameliorates glucose homeostasis in mice through a PPAR γ-dependent mechanism and modulates macrophage and Treg cell infiltration into the abdominal white adipose tissue.
  • Thumbnail Image
    Immunoregulatory Actions of Epithelial Cell PPAR γ at the Colonic Mucosa of Mice with Experimental Inflammatory Bowel Disease
    Mohapatra, Saroj K.; Guri, Amir J.; Climent, Montse; Vives, Cristina; Carbo, Adria; Horne, William T.; Hontecillas, Raquel; Bassaganya-Riera, Josep (Public Library of Science, 2010-04-20)
    Background: Peroxisome proliferator-activated receptors are nuclear receptors highly expressed in intestinal epithelial cells (IEC) and immune cells within the gut mucosa and are implicated in modulating inflammation and immune responses. The objective of this study was to investigate the effect of targeted deletion of PPAR γ in IEC on progression of experimental inflammatory bowel disease (IBD). Methodology/Principal Findings: In the first phase, PPAR γ flfl; Villin Cre- (VC-) and PPAR γ flfl; Villin Cre+ (VC+) mice in a mixed FVB/C57BL/6 background were challenged with 2.5% dextran sodium sulfate (DSS) in drinking water for 0, 2, or 7 days. VC+ mice express a transgenic recombinase under the control of the Villin-Cre promoter that causes an IEC-specific deletion of PPAR γ. In the second phase, we generated VC- and VC+ mice in a C57BL/6 background that were challenged with 2.5% DSS. Mice were scored on disease severity both clinically and histopathologically. Flow cytometry was used to phenotypically characterize lymphocyte and macrophage populations in blood, spleen and mesenteric lymph nodes. Global gene expression analysis was profiled using Affymetrix microarrays. The IEC-specific deficiency of PPAR γ in mice with a mixed background worsened colonic inflammatory lesions, but had no effect on disease activity (DAI) or weight loss. In contrast, the IEC-specific PPAR γ null mice in C57BL/6 background exhibited more severe inflammatory lesions, DAI and weight loss in comparison to their littermates expressing PPAR γ in IEC. Global gene expression profiling revealed significantly down-regulated expression of lysosomal pathway genes and flow cytometry results demonstrated suppressed production of IL-10 by CD4+ T cells in mesenteric lymph nodes (MLN) of IEC-specific PPAR γ null mice. Conclusions/Significance: Our results demonstrate that adequate expression of PPAR γ in IEC is required for the regulation of mucosal immune responses and prevention of experimental IBD, possibly by modulation of lysosomal and antigen presentation pathways.
  • Thumbnail Image
    Method of preventing and treating inflammatory diseases and disorders with abscisic acid
    (United States Patent and Trademark Office, 2015-03-31)
    The present invention relates to the use of a therapeutically effective amount of abscisic acid (ABA) or its analogs to treat or prevent inflammation induced by exposure to lipopolysaccharide (LPS) or respiratory inflammation. The invention also relates to methods and composition for enhancing vaccine efficacy using ABA.
  • Thumbnail Image
    Method of synergistically enhancing the therapeutic efficacy and safety of medication through a combination therapy
    (United States Patent and Trademark Office, 2015-09-01)
    The present invention provides combinations, for treatment of subjects suffering from or at high risk of developing diseases and disorders involving expression of peroxisome proliferator-activated receptors (PPAR). The combinations include abscisic acid and one other bioactive agent, which together provide synergistic effects toward treatment or blocking of development of the disease or disorder. In exemplary embodiments, a combination of abscisic acid and a thiazolidinedione (TZD) is provided for increased insulin sensitivity and improved (i.e., reduced) obesity-induced inflammation.
  • Thumbnail Image
    Method of using abscisic acid to treat diseases and disorders
    (United States Patent and Trademark Office, 2010-06-22)
    The present invention provides compositions and methods for treating and/or preventing diseases and disorders associated with expression of PPAR γ and/or infiltration of macrophages into skeletal muscle tissue and/or white adipose tissue. The method treats such diseases and disorders with abscisic acid (ABA). Exemplary diseases and disorders include diabetes, including type 2 diabetes, prediabetes, glucose intolerance insulin resistance, and diseases and disorders involving the immune system, such as inflammation, including obesity-related inflammation, inflammatory bowel disease, type 1 diabetes, multiple sclerosis, allergies, asthma, cardiovascular disease, and arthritis.
  • Thumbnail Image
    Method of using abscisic acid to treat diseases and disorders
    (United States Patent and Trademark Office, 2013-02-05)
    Methods and compositions for treating inflammatory bowel disease, gastrointestinal inflammation and maintaining normal gut health are described. These methods of the invention involve the administration of abscisic acid in amounts sufficient to alter the expression or activity of PPAR gamma in a cell. Also described are methods for suppressing the expression of cellular adhesion molecules in the gut and methods for increasing CTLA-4 expression on CD4+ T cells through administration of abscisic acid.
  • Thumbnail Image
    The role of T cell PPARgamma in mice with experimental inflammatory bowel disease
    Guri, Amir J.; Mohapatra, Saroj K.; Horne, William T.; Hontecillas, Raquel; Bassaganya-Riera, Josep (2010-06-10)
    Background Peroxisome proliferator-activated receptor Ω (PPAR Ω) is a nuclear receptor whose activation has been shown to modulate macrophage and T cell-mediated inflammation. The objective of this study was to investigate the mechanisms by which the deletion of PPAR Ω in T cells modulates immune cell distribution and colonic gene expression and the severity of experimental IBD. Methods PPAR Ω flfl; CD4 Cre+ (CD4cre) or Cre- (WT) mice were challenged with 2.5% dextran sodium sulfate in their drinking water for 0, 2, or 7 days. Mice were scored on disease severity both clinically and histopathologically. Flow cytometry was used to assess lymphocyte and macrophage populations in the blood, spleen, and mesenteric lymph nodes (MLN). Global gene expression in colonic mucosa was profiled using Affymetrix microarrays. Results The deficiency of PPAR Ω in T cells accelerated the onset of disease and body weight loss. Examination of colon histopathology revealed significantly greater epithelial erosion, leukocyte infiltration, and mucosal thickening in the CD4cre mice on day 7. CD4cre mice had more CD8+ T cells than WT mice and fewer CD4+FoxP3+ regulatory T cells (Treg) and IL10+CD4+ T cells in blood and MLN, respectively. Transcriptomic profiling revealed around 3000 genes being transcriptionally altered as a result of DSS challenge in CD4cre mice. These included up-regulated mRNA expression of adhesion molecules, proinflammatory cytokines interleukin-6 (IL-6) and IL-1β, and suppressor of cytokine signaling 3 (SOCS-3) on day 7. Gene set enrichment analysis (GSEA) showed that the ribosome and Krebs cycle pathways were downregulated while the apoptosis pathway was upregulated in colons of mice lacking PPAR Ω in T cells. Conclusions The expression of PPAR Ω in T cells is involved in preventing gut inflammation by regulating colonic expression of adhesion molecules and inflammatory mediators at later stages of disease while favoring the recruitment of Treg to the mucosal inductive sites.
  • Thumbnail Image
    Treatment of Obesity-Related Complications with Novel Classes of Naturally Occurring PPAR Agonists
    Bassaganya-Riera, Josep; Guri, Amir J.; Hontecillas, Raquel (Hindawi, 2010-12-28)
    The prevalence of obesity and its associated comorbidities has grown to epidemic proportions in the US and worldwide. Thus, developing safe and effective therapeutic approaches against these widespread and debilitating diseases is important and timely. Activation of peroxisome proliferator-activated receptors (PPARs) α, γ, and δ through several classes of pharmaceuticals can prevent or treat a variety of metabolic and inflammatory diseases, including type II diabetes (T2D). Thus, PPARs represent important molecular targets for developing novel and better treatments for a wide range of debilitating and widespread obesity-related diseases and disorders. However, available PPAR γ agonistic drugs such as Avandia have significant adverse side effects, including weight gain, fluid retention, hepatotoxicity, and congestive heart failure. An alternative to synthetic agonists of PPAR γ is the discovery and development of naturally occurring and safer nutraceuticals that may be dual or pan PPAR agonists. The purpose of this paper is to summarize the health effects of three plant-derived PPAR agonists: abscisic acid (ABA), punicic acid (PUA), and catalpic acid (CAA) in the prevention and treatment of chronic inflammatory and metabolic diseases and disorders.