lipoteichoic-acid and Colitis

Lipoteichoic acid (LTA) is a key surface component of probiotic lactobacilli that is involved in important cellular functions including cross talk with the host immune cells. In this study, the anti-inflammatory and ameliorative properties of LTA from probiotic lactobacilli strains were assessed in in vitro HT-29 cells and in vivo colitis mice. The LTA was extracted with n-butanol and its safety was confirmed based on its endotoxin content and cytotoxicity in HT-29 cells. In the Lipopolysaccharide stimulated HT-29 cells, the LTA from the test probiotics evoked a visible but non-significant increase in IL-10 and decrease in TNF-α levels. During the colitis mice study, probiotic LTA treated mice showed substantial improvement in external colitis symptoms, disease activity score and weight gain. The treated mice also showed improvements in key inflammatory markers such as the gut permeability, myeloperoxidase activity and histopathological damages in colon, although non-significant improvements were recorded for the inflammatory cytokines. Furthermore, structural studies by NMR and FTIR revealed increased level of D-alanine substitution in the LTA of LGG strain over MTCC5690. The present study demonstrates the ameliorative effect of LTA as a postbiotic component from probiotics which can be helpful in building effective strategies for combating gut inflammatory disorders.

Topics: Animals; Colitis; Cytokines; HT29 Cells; Humans; Inflammation; Lactobacillus; Lipopolysaccharides; Mice; Probiotics

Lipoteichoic acid (LTA) mutants of lactobacilli suppress inflammation in animal models of experimental colitis. The fact that a single mutation of an administered Lactobacillus strain can result in enhanced probiotic efficacy is surprising given the genetic diversity and complexity of the intestinal niche, but at the same time exciting from a microbiological, immunological and gastroenterological point of view. In this Opinion article, we discuss the possible impacts of LTA modification in probiotic bacteria in the context of the current knowledge regarding the proinflammatory capacity of LTA, structure-activity relationships of LTA, intestinal LTA recognition in healthy and colitis conditions and anti-inflammatory molecules of lactobacilli.

Topics: Anti-Inflammatory Agents; Colitis; Humans; Lactobacillus; Lipopolysaccharides; Probiotics; Structure-Activity Relationship; Teichoic Acids

To investigate the mechanism(s) by which the intestinal commensal microbe Lactobacillus acidophilus can affect host immunity, we studied the role of a component of the cell wall, lipoteichoic acid, in colitis.. Colitis was induced by the intraperitoneal injection of pathogenic CD4(+)CD25(-)CD45RB(hi) T cells into Rag1(-/-) mice. The parental strain, NCK56, or the lipoteichoic acid-deficient strain, NCK2025, was then administered orally. Fluorescent microscopy was employed to examine resulting cell populations and their cytokine production in the colon.. NCK2025 enhanced IL-10 production by dendritic cells and macrophages. Increased numbers of regulatory dendritic cells coincided with the induction of activated FoxP3(+) Tregs.. These results suggest that the oral administration of the genetically modified strain NCK2025 may be an effective immunotherapeutic approach that reprograms the immune response in colonic inflammatory conditions.

Topics: Animals; Antigens, Bacterial; Antigens, CD; Cells, Cultured; Colitis; Colon; Dendritic Cells; Forkhead Transcription Factors; Immunomodulation; Interleukin-10; Lactobacillus acidophilus; Lipopolysaccharides; Macrophages, Peritoneal; Mice; Mice, Knockout; T-Lymphocyte Subsets; T-Lymphocytes, Regulatory; Teichoic Acids; Up-Regulation

It is believed that inflammatory bowel diseases (IBD) result from an imbalance in the intestinal immune response towards the luminal microbiome. Dectin-1 is a widely expressed pattern recognition receptor that recognizes fungi and upon recognition it mediates cytokine responses and skewing of the adaptive immune system. Hence, dectin-1 may be involved in the pathogenesis of IBD.. We assessed the responses of dectin-1 deficient macrophages to the intestinal microbiota and determined the course of acute DSS and chronic Helicobacter hepaticus induced colitis in dectin-1 deficient mice.. We show that the mouse intestinal microbiota contains fungi and the cytokine responses towards this microbiota were significantly reduced in dectin-1 deficient macrophages. However, in two different colitis models no significant differences in the course of inflammation were found in dectin-1 deficient mice compared to wild type mice.. Together our data suggest that, although at the immune cell level there is a difference in response towards the intestinal flora in dectin-1 deficient macrophages, during intestinal inflammation this response seems to be redundant since dectin-1 deficiency in mice does not affect intestinal inflammation in experimental colitis.

Topics: Animals; Colitis; Dextran Sulfate; Feces; Helicobacter hepaticus; Interleukin-10; Intestine, Large; Lectins, C-Type; Lipopolysaccharides; Macrophages; Metagenome; Mice; Mice, Inbred C57BL; Rhodotorula; Teichoic Acids; Tumor Necrosis Factor-alpha; Zymosan

Imbalance in the regulatory immune mechanisms that control intestinal cellular and bacterial homeostasis may lead to induction of the detrimental inflammatory signals characterized in humans as inflammatory bowel disease. Induction of proinflammatory cytokines (i.e., IL-12) induced by dendritic cells (DCs) expressing pattern recognition receptors may skew naive T cells to T helper 1 polarization, which is strongly implicated in mucosal autoimmunity. Recent studies show the ability of probiotic microbes to treat and prevent numerous intestinal disorders, including Clostridium difficile-induced colitis. To study the molecular mechanisms involved in the induction and repression of intestinal inflammation, the phosphoglycerol transferase gene that plays a key role in lipoteichoic acid (LTA) biosynthesis in Lactobacillus acidophilus NCFM (NCK56) was deleted. The data show that the L. acidophilus LTA-negative in LTA (NCK2025) not only down-regulated IL-12 and TNFα but also significantly enhanced IL-10 in DCs and controlled the regulation of costimulatory DC functions, resulting in their inability to induce CD4(+) T-cell activation. Moreover, treatment of mice with NCK2025 compared with NCK56 significantly mitigated dextran sulfate sodium and CD4(+)CD45RB(high)T cell-induced colitis and effectively ameliorated dextran sulfate sodium-established colitis through a mechanism that involves IL-10 and CD4(+)FoxP3(+) T regulatory cells to dampen exaggerated mucosal inflammation. Directed alteration of cell surface components of L. acidophilus NCFM establishes a potential strategy for the treatment of inflammatory intestinal disorders.

Topics: Animals; Autoimmunity; CD4-Positive T-Lymphocytes; Colitis; Dextran Sulfate; DNA Primers; Flow Cytometry; Fluorescent Antibody Technique; Gene Deletion; Gene Expression Regulation; Homeodomain Proteins; Interleukin-10; Lactobacillus acidophilus; Lipopolysaccharides; Mice; Mice, Inbred C57BL; Mice, Knockout; Myeloid Differentiation Factor 88; Polymerase Chain Reaction; Teichoic Acids; Transferases (Other Substituted Phosphate Groups)

The trillions of microbes residing within the intestine induce critical signals that either regulate or stimulate host immunity via their bacterial products. To better understand the immune regulation elicited by lipoteichoic acid (LTA)-deficient Lactobacillus acidophilus NCFM in steady state and induced inflammation, we deleted phosphoglycerol transferase gene, which synthesizes LTA in L. acidophilus NCFM. In vitro and in vivo experiments were conducted in order to compare the immune regulatory properties of the L. acidophilus strain deficient in LTA (NCK2025) with its wild-type parent (NCK56) in C57BL/6, C57BL/6 recombination-activation gene 1-deficient (Rag1 (-/-)) and C57BL/6 Rag1(-/-)IL-10(-/-) mice. We demonstrate that NCK2025 significantly activates the phosphorylation of Erk1/2 but downregulates the phosphorylation of Akt1, cytosolic group IV PLA2 and p38 in mouse dendritic cells. Similarly, mice treated orally with NCK2025 exhibit decreased phosphorylation of inflammatory signals (Akt1, cytosolic group IV PLA2 or P38) but upregulate Erk1/2-phosphorylation in colonic epithelial cells in comparison with mice treated with NCK56. In addition, regulation of pathogenic CD4+ T cell induced colitis by NCK2025 was observed in Rag1 (-/-) but not Rag1(-/-)IL-10 (-/-) mice suggests a critical role of IL-10 that may be tightly regulated by Erk1/2 signaling. These data highlight the immunosuppressive properties of NCK2025 to deliver regulatory signals in innate cells, which results in the mitigation of T-cell-induced colitis in vivo.

Topics: Animals; CD4-Positive T-Lymphocytes; Colitis; Dendritic Cells; Group IV Phospholipases A2; Interleukin-10; Lactobacillus acidophilus; Lipopolysaccharides; Mice; Mice, Inbred C57BL; Mice, Transgenic; Mitogen-Activated Protein Kinase 3; p38 Mitogen-Activated Protein Kinases; Proto-Oncogene Proteins c-akt; Signal Transduction; T-Lymphocytes, Regulatory; Teichoic Acids; Transferases (Other Substituted Phosphate Groups)

Chronic colitis-harboring TCRalpha(- / - ) x AIM(- / - ) mice showed PBC-like bile duct damage in the liver. Bacterial infection is one of the candidates for the pathogenesis of PBC. We demonstrated that the bacterial cell wall component lipotheicoic acid (LTA) was detected at sites of inflammation around damaged bile ducts in PBC patients. The aim of this study was to investigate the pathophysiology of the liver and other organs in TCRalpha(- / - ) x AIM(- / - ) mice.. Thirteen female TCRalpha(- / - ) x AIM(- / - ) mice were sacrificed at 24 weeks of age. The liver, stomach, small intestine, colon, pancreas, kidney and spleen were studied for pathological examination. Using anti-LTA antibody as the primary antibody, an immunohistochemical study was carried out.. In the liver, LTA was mainly detected in the portal area with inflammation, and some of the cytoplasm of hepatocytes. Inflammations were also observed in the stomach, intestine, pancreas and kidney. Throughout the gastrointestinal tract, from the stomach to the colon, LTA was detected in the epithelium at sites of inflammation. Furthermore, LTA was detected around both pancreatic ducts with inflammation and distal renal tubules with inflammation.. The development of inflammations in the liver as well as extensive organs, strongly suggests a close relationship between bile duct damage and systemic multifocal epithelial inflammations, perhaps involving bacterial LTA, in TCRalpha(- / - ) x AIM(- / - ) mice.

Topics: Animals; Bile Ducts, Intrahepatic; Chronic Disease; Colitis; Epithelium; Female; Gram-Positive Bacteria; Inflammation; Intestine, Small; Kidney; Lipopolysaccharides; Liver; Liver Cirrhosis, Biliary; Mice; Pancreas; Spleen; Teichoic Acids

Autoimmune disorder and associated multifocal organ inflammations such as dry gland syndrome are occasionally observed; however, their etiologies are not clearly understood. We previously reported that chronic colitis-harboring TCR alpha(-/-) x AIM(-/-) mice show primary biliary cirrhosis (PBC)-like bile duct damage in the liver. Gram-positive bacterial infection is one of the candidates for the pathogenesis of PBC. We also reported that the bacterial cell wall component lipoteichoic acid (LTA) was detected at the sites of inflammation around damaged bile ducts in PBC patients. On the basis of these facts, we hypothesized that LTA might affect the pathogenesis of bile duct damage in the livers of TCR alpha(-/-) x AIM(-/-) mice. LTA was detected not only in the portal area with inflammation in the liver but also throughout the gastrointestinal tract, from the stomach to the colon, and especially in the epithelium at sites of inflammation. In addition, LTA was detected around both pancreatic ducts with inflammation and at the distal renal tubules with inflammation in TCR alpha(-/-) x AIM(-/-) mice. Furthermore, in the liver, pancreas, kidney, and colon, fibrous stroma were detected at the sites of LTA-positive inflammation foci. Bacterial LTA might affect the pathogenesis of epithelial inflammation followed by fibrosis in systemic multifocal epithelial inflammations in chronic colitis-harboring TCR alpha(-/-) x AIM(-/-) mice with PBC-like bile duct damage.

Topics: Animals; Apoptosis Regulatory Proteins; Colitis; Epithelium; Fibrosis; Inflammation; Lipopolysaccharides; Liver Cirrhosis, Biliary; Mice; Mice, Knockout; Receptors, Antigen, T-Cell, alpha-beta; Receptors, Immunologic; Receptors, Scavenger; Teichoic Acids

Teichoic acids (TAs), and especially lipoteichoic acids (LTAs), are one of the main immunostimulatory components of pathogenic Gram-positive bacteria. Their contribution to the immunomodulatory properties of commensal bacteria and especially of lactic acid bacteria has not yet been investigated in detail. To evaluate the role of TAs in the interaction between lactic acid bacteria and the immune system, we analyzed the antiinflammatory properties of a mutant of Lactobacillus plantarum NCIMB8826 affected in the TA biosynthesis pathway both in vitro (mononuclear cells stimulation) and in vivo (murine model of colitis). This Dlt- mutant was found to incorporate much less D-Ala in its TAs than the WT strain. This defect significantly impacted the immunomodulation reactions induced by the bacterium, as shown by a dramatically reduced secretion of proinflammatory cytokines by peripheral blood mononuclear cells and monocytes stimulated by the Dlt- mutant as compared with the parental strain. Concomitantly, a significant increase in IL-10 production was stimulated by the Dlt- mutant in comparison with the WT strain. Moreover, the proinflammatory capacity of L. plantarum-purified LTA was found to be Toll-like receptor 2-dependent. Consistent with the in vitro results, the Dlt- mutant was significantly more protective in a murine colitis model than its WT counterpart. The results indicated that composition of LTA within the whole-cell context of L. plantarum can modulate proinflammatory or antiinflammatory immune responses.

Topics: Analysis of Variance; Animals; Anti-Inflammatory Agents; Cloning, Molecular; Colitis; Cytokines; DNA Primers; Genetic Vectors; Humans; Immunologic Factors; Lactobacillus plantarum; Leukocytes, Mononuclear; Lipopolysaccharides; Membrane Transport Proteins; Mice; Mice, Inbred BALB C; Mutation; Saliva; Teichoic Acids

Commensal and enteroinvasive microbes in the human gut release bacterial flagellin, a specific microbial ligand of Toll-like receptor 5 (TLR5). However, the pathophysiological role of bacterial flagellin in gastrointestinal inflammation has not been determined. Here we evaluated the role of bacterial flagellin using native human colonic mucosa and the mouse colitis model of dextran sulfate sodium (DSS). We demonstrate that, in intact human colonic mucosa, the flagellin/TLR5 response occurs only after exposure to the basolateral, not the apical, surface, implying a basolaterally polarized TLR5 response in human colonic mucosa. In this context, flagellin exposure to injured colonic mucosa due to DSS administration in mice resulted in a TLR5-associated response evaluated by in vivo activation of mitogen-activated protein kinase/extracellular signal-related kinase 1/2 (MEK1/2) and elevated IL-6, TNF-alpha, and keratinocyte-derived chemokine production, whereas intact colonic mucosa did not respond to flagellin. Moreover, flagellin exposure to injured mouse colon in vivo, but not to intact colon, also significantly aggravated colonic inflammation, increased mouse mortality, and enhanced histopathological damage in the colonic mucosa. However, the TLR2-specific agonist, peptidoglycan or lipoteichoic acid, did not cause an inflammatory response in intact or DSS-injured mouse colon. Furthermore, intracolonic flagellin administration in mice causes severe apoptosis in colonic epithelium disrupted by DSS administration. These data suggest that intracolonic flagellin via TLR5 engagement is able to elicit inflammatory responses in disrupted colon, whereas the normal colon is not responsive to bacterial flagellin. These results demonstrate that bacterial flagellin plays an important role in the development and progress of colitis.

Topics: Animals; Apoptosis; Chemokines; Colitis; Colon; Flagellin; Humans; Inflammation; Interleukin-6; Intestinal Mucosa; Keratinocytes; Lipopolysaccharides; Male; MAP Kinase Kinase 1; MAP Kinase Kinase 2; Membrane Glycoproteins; Mice; Peptidoglycan; Receptors, Cell Surface; Signal Transduction; Teichoic Acids; Tissue Culture Techniques; Toll-Like Receptor 2; Toll-Like Receptor 5; Toll-Like Receptors; Tumor Necrosis Factor-alpha