neuropeptide-y and Colitis

Enteroendocrine cells (EEC) produce neuropeptides, which are crucially involved in the maintenance of the intestinal barrier. Hence, EEC dysfunction is suggested to be involved in the complex pathophysiology of inflammatory bowel disease (IBD), which is characterized by decreased intestinal barrier function. However, the underlying mechanisms for EEC dysfunction are not clear and suitable models for a better understanding are lacking. Here, we demonstrate that Carboxypeptidase E (CPE) is specifically expressed in EEC of the murine colon and ileum and that its deficiency is associated with reduced intestinal levels of Neuropeptide Y (NPY) and Peptide YY (PYY), which are both produced by EEC. Moreover, cpe-/- mice exhibit an aggravated course of DSS-induced chronic colitis compared to wildtype littermates. In addition, we observed elevated mucosal IL-6 and KC transcript levels already at baseline conditions in cpe-/- mice. Moreover, supernatants obtained from isolated intestinal crypts of cpe-/- mice lead to increased IL-6 and KC expression in MODE-K cells in the presence of LPS. This effect was reversible by co-administration of recombinant NPY, suggesting a CPE mediated immunosuppressive effect in the intestines by influencing the processing of specific neuropeptides. In this context, the chemotaxis of bone marrow derived macrophages towards respective supernatants was enhanced. In conclusion, our data point to an anti-inflammatory role of CPE in the intestine by influencing local cytokine levels and thus regulating the migration of myeloid immune cells into the mucosa. These findings highlight the importance of EEC for intestinal homeostasis and propose EEC as potential therapeutic targets in IBD.

Topics: Animals; Carboxypeptidase H; Cell Movement; Cells, Cultured; Chromogranin B; Colitis; Colon; Dextran Sulfate; Homeostasis; Humans; Inflammatory Bowel Diseases; Intestinal Mucosa; Mice, Inbred C57BL; Myeloid Cells; Neuropeptide Y; Protein Transport

Neuro-immune interactions play a significant role in regulating the severity of inflammation. Our previous work demonstrated that neuropeptide Y (NPY) is upregulated in the enteric nervous system during murine colitis and that NPY knockout mice exhibit reduced inflammation. Here, we investigated if NPY expression during inflammation is induced by tumor necrosis factor (TNF), the main proinflammatory cytokine.. Using primary enteric neurons and colon explant cultures from wild type and NPY knockout (NPY(-/-)) mice, we determined if NPY knockdown modulates TNF release and epithelial permeability. Further, we assessed if NPY expression is inducible by TNF in enteric neuronal cells and mouse model of experimental colitis, using the TNF inhibitors-etanercept (blocks transmembrane and soluble TNF) and XPro1595 (blocks soluble TNF only).. We found that enteric neurons express TNF receptors (TNFR1 and R2). Primary enteric neurons from NPY(-/-) mice produced less TNF compared with wild type. Further, TNF activated NPY promoter in enteric neurons through phospho-c-Jun. NPY(-/-) mice had decreased intestinal permeability. In vitro, NPY increased epithelial permeability through phosphatidyl inositol-3-kinase (PI3-K)-induced pore-forming claudin-2. TNF inhibitors attenuated NPY expression in vitro and in vivo. TNF inhibitor-treated colitic mice exhibited reduced NPY expression and inflammation, reduced oxidative stress, enhanced neuronal survival, and improved colonic motility. XPro1595 had more protective effects on neuronal survival and motility compared with etanercept.. We demonstrate a novel TNF-NPY cross talk that modulates inflammation, barrier functions, and colonic motility during inflammation. It is also suggested that selective blocking of soluble TNF may be a better therapeutic option than using anti-TNF antibodies.

Topics: Animals; Blotting, Western; Case-Control Studies; Cell Membrane Permeability; Chromatin Immunoprecipitation; Colitis; Colon; Cytokines; Disease Models, Animal; Electric Conductivity; Enteric Nervous System; Gastrointestinal Motility; Humans; Intestinal Mucosa; Laser Capture Microdissection; Mice; Mice, Knockout; Mutagenesis, Site-Directed; Neuropeptide Y; Phosphatidylinositol 3-Kinases; Signal Transduction; Tumor Necrosis Factor-alpha

The present study examines the chemical coding of the inferior mesenteric ganglia after chemically induced colitis in the pig animal model. In all animals (n = 6), a median laparotomy was performed under anesthesia, and the Fast Blue retrograde tracer was injected into the descending colon wall. In experimental animals (n = 3), the thick descending colon were injected with formalin solution to induce inflammation. The animals were euthanized and the inferior mesenteric ganglion was harvested and processed for double-labeling immunofluorescence for calbindin-D28k (CB) in combination with either tyrosine hydroxylase (TH), neuropeptide Y (NPY), somatostatin (SOM), vasoactive intestinal polypeptide (VIP), nitric oxide synthase (NOS), Leu-enkephalin (LENK), substance P (SP), vesicular acetylcholine transporter (VAChT), or galanin (GAL). Immunohistochemistry revealed significant changes in the chemical coding pattern of inferior mesenteric ganglion neurons. In control animals, Fast Blue-positive neurons were immunoreactive to TH, NPY, SOM, VIP, LENK, CB, and NOS. In the experimental group, TH, NPY, SOM, VIP, and LENK expressing neurons were reduced, whereas the number of neurons immunoreactive to CB, NOS, and GAL were increased. The increase of so-called neuroprotective neuropeptides suggests that the changes in the chemical coding of inferior mesenteric ganglion neurons reflect adaption under pathological conditions to promote their own survival.

Topics: Animals; Cell Count; Cell Survival; Colitis; Colon; Disease Models, Animal; Enteric Nervous System; Female; Formaldehyde; Ganglia, Sympathetic; Gene Expression Regulation; Nerve Tissue Proteins; Neurons; Neuropeptide Y; Neuropeptides; Neurotransmitter Agents; Sus scrofa; Swine

Peptide YY (PYY) and neuropeptide Y (NPY) are involved in regulating gut and brain function. Because gastrointestinal inflammation is known to enhance anxiety, we explored whether experimental colitis interacts with genetic deletion (knockout) of PYY and NPY to alter emotional-affective behaviour.. Male and female wild-type, NPY (NPY(-/-) ), PYY (PYY(-/-) ) and NPY(-/-) ; PYY(-/-) double knockout mice were studied in the absence and presence of mild colitis induced by ingestion of dextran sulphate sodium (2%) in drinking water. Anxiety-like behaviour was tested on the elevated plus maze and open field, and depression-like behaviour assessed by the forced swim test.. In the absence of colitis, anxiety-like behaviour was increased by deletion of NPY but not PYY in a test- and sex-dependent manner, while depression-like behaviour was enhanced in NPY(-/-) and PYY(-/-) mice of either sex. The severity of DSS-induced colitis, assessed by colonic myeloperoxidase content, was attenuated in NPY(-/-) but not PYY(-/-) mice. Colitis modified anxiety- and depression-related behaviour in a sex-, genotype- and test-related manner, and knockout experiments indicated that NPY and PYY were involved in some of these behavioural effects of colitis.. These data demonstrate sex-dependent roles of NPY and PYY in regulation of anxiety- and depression-like behaviour in the absence and presence of colitis. Like NPY, the gut hormone PYY has the potential to attenuate depression-like behaviour but does not share the ability of NPY to reduce anxiety-like behaviour.

Topics: Animals; Anxiety; Behavior, Animal; Colitis; Depression; Dextran Sulfate; Female; Gene Expression Regulation; Male; Mice; Mice, Knockout; Neuropeptide Y; Peptide YY; Peroxidase; Sex Characteristics

Causal connections between dipeptidyl peptidase IV, also known as CD26 molecule (DPP IV/CD26) and inflammatory bowel disease (IBD) have been shown, but mechanisms of these interactions are unclear. Our hypothesis was that DPP IV/CD26 could affect the neuroimmune response during inflammatory events. Therefore, we aimed to evaluate its possible role and the relevance of the gut-brain axis in a model of IBD in mice. Trinitrobenzenesulfonic acid-induced (TNBS) colitis was induced in CD26-deficient (CD26(-/-) ) and wild-type (C57BL/6) mice. Pathohistological and histomorphometrical measurements were done. Concentrations and protein expressions of DPP IV/CD26 substrates neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP) were determined. Concentrations of IL-6 and IL-10 were evaluated. Investigations were conducted at systemic and local levels. Acute inflammation induced increased serum NPY concentrations in both mice strains, more enhanced in CD26(-/-) mice. Increased NPY concentrations were found in colon and brain of C57BL/6 mice, while in CD26(-/-) animals only in colon. VIP and IL-6 serum and tissue concentrations were increased in both mice strains in acute inflammation, more pronouncedly in CD26(-/-) mice. IL-10 concentrations, after a decrease in serum of both mice strains, increased promptly in CD26(-/-) mice. Decreased IL-10 concentration was found in brain of C57BL/6 mice, while it was increased in colon of CD26(-/-) mice in acute inflammation. DPP IV/CD26 deficiency affects the neuroimmune response at systemic and local levels during colitis development and resolution in mice. Inflammatory changes in the colon reflected on investigated parameters in the brain, suggesting an important role of the gut-brain axis in IBD pathogenesis.

Topics: Animals; Blotting, Western; Colitis; Dipeptidyl Peptidase 4; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Interleukins; Mice; Mice, Knockout; Neuropeptide Y; Trinitrobenzenesulfonic Acid; Vasoactive Intestinal Peptide

Colonic inflammation involves the changes in chemical coding of not only sensory but also enteric and sympathetic prevertebral neurons innervating inflamed target tissue. Since the sympathetic chain ganglia neurons (SChG) affect colonic function, the purpose of our study was to determine the precise location of the SChG neurons innervating the porcine descending colon, define their chemical coding and answer the question of whether paraformaldehyde-induced colitis in female pigs is able to change the chemical phenotype of the perikarya. Using the Fast Blue (FB) retrograde tracing, the greatest concentration of the (FB+) perikarya was revealed in L₃ ganglia. Applying double immunohistochemistry, we detected a strongly catecholaminergic character and in majority neuropeptide Y (NPY)-positive staining of the colon-projecting FB+ neurons both in the control and the inflamed animals. Furthermore, colonic inflammation caused the significant increase in density of galanin- (P<0.001), somatostatin- (P<0.005), leu5-enkephalin- (P<0.05), substance P- (P<0.005), and calcitonin gene-related peptide- (P<0.005) immunoreactive (-IR) nerve fibers surrounding the FB+ perikarya, while the density of nitric oxide synthase-IR and NPY-IR fibers remained unaffected compared to the control animals. The increase in visible immunofluorescent detection of neuropeptide-containing fibers could possibly be caused by enhanced demand and release of neuropeptides that modulate intestinal immune response and regulate the gastrointestinal activity through inflammatory mediators.

Topics: Amidines; Animals; Colitis; Colon; Female; Formaldehyde; Ganglia, Sympathetic; Immunohistochemistry; Inflammation; Nerve Fibers; Neurons; Neuropeptide Y; Polymers; Swine

Neuropeptide Y (NPY) from enteric neurons has been shown to play an important role in immune and inflammatory responses. The purpose of the present study was to investigate the effects of NPY antisense oligodeoxynucleotides (ODNs) on an experimental model of ulcerative colitis (UC).. NPY antisense ODNs were administered in experimental colitis induced by dextran sulfate sodium (DSS). The disease activity index (DAI) and histological score were observed. The tumor necrosis factor (TNF)-alpha and NPY levels were measured by enzyme-linked immunosorbent assay. Phosphorylated Akt (p-Akt) expression was determined by immunohistochemical staining. Activated nuclear factor (NF)-kappaB was assessed by western blot analysis. Myeloperoxidase (MPO) activity was determined by using MPO assay kit.. A significant improvement was observed in DAI and histological score in rats with NPY antisense ODNs, and the increase in NPY and TNF-alpha levels, MPO activity, and the expression p-Akt and p-NF-kappaB in rats with DSS-induced colitis was significantly reduced following the administration of NPY antisense ODNs.. The administration of NPY antisense ODNs leads to an amelioration of DSS-induced colitis, suggesting that NPY plays an important role in modulating inflammation in colitis, and NPY antisense ODNs may be a useful therapeutic approach to the treatment of UC.

Topics: Animals; Colitis; Dextran Sulfate; Fluorescein-5-isothiocyanate; Intestinal Mucosa; Male; Neuropeptide Y; Oligodeoxyribonucleotides; Peroxidase; Phosphatidylinositol 3-Kinases; Phosphorylation; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Signal Transduction; Transcription Factor RelA; Tumor Necrosis Factor-alpha

Regulation of water movement in the gut is an important homeostatic event that is critical to normal intestinal function. We assessed the effect of neuropeptide Y (NPY) on epithelial ion transport in the normal and inflamed mouse colons. Colitis was induced by dextran sodium sulfate (DSS, 4% wt./vol.) administered in the drinking water for 5 days followed by 3 days of regular water. Segments of proximal and distal colons were excised and short-circuit current (I(SC)) was measured in Ussing chambers to assess net electrogenic active ion transport. NPY Y(1) receptor (Y(1)R) expression was measured by quantitative real-time PCR and immunohistochemistry. Challenge of distal colon from normal mice with NPY (10(-7)M) evoked a drop in I(SC) (51.4±9.1 μA/cm(2)), which was dependent on Cl(-) flux, was insensitive to neural blockade with tetrodotoxin and was mediated primarily through the Y(1)R. In contrast, the proximal colon was largely unresponsive to NPY, expressing ~ten-fold less Y(1)R mRNA compared to the distal colon. These findings confirm that specific regional regulation of ion transport occurs in the colon. Segments of proximal and distal colons from mice with DDS-induced colitis were virtually unresponsive to NPY, expressed less Y(1)R mRNA than tissues from control mice and displayed loss of Y(1)R protein expression in the colonic epithelium. This hypo-responsiveness to an antisecretory stimulus adds to the well-documented loss of responsiveness to pro-secretory agents during inflammation, attesting to a profound loss of control of active ion transport during enteric inflammatory disease.

Topics: Animals; Colitis; Colon; Dextran Sulfate; Immunohistochemistry; Ion Transport; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Neuropeptide Y; Polymerase Chain Reaction

Neurogenic inflammation plays a major role in the pathogenesis of inflammatory bowel disease (IBD). We examined the role of neuropeptide Y (NPY) and neuronal nitric oxide synthase (nNOS) in modulating colitis.. Colitis was induced by administration of dextran sodium sulphate (3% DSS) or streptomycin pre-treated Salmonella typhimurium (S.T.) in wild type (WT) and NPY (NPY(-/-)) knockout mice. Colitis was assessed by clinical score, histological score and myeloperoxidase activity. NPY and nNOS expression was assessed by immunostaining. Oxidative stress was assessed by measuring catalase activity, glutathione and nitrite levels. Colonic motility was assessed by isometric muscle recording in WT and DSS-treated mice.. DSS/S.T. induced an increase in enteric neuronal NPY and nNOS expression in WT mice. WT mice were more susceptible to inflammation compared to NPY(-/-) as indicated by higher clinical & histological scores, and myeloperoxidase (MPO) activity (p<0.01). DSS-WT mice had increased nitrite, decreased glutathione (GSH) levels and increased catalase activity indicating more oxidative stress. The lower histological scores, MPO and chemokine KC in S.T.-treated nNOS(-/-) and NPY(-/-)/nNOS(-/-) mice supported the finding that loss of NPY-induced nNOS attenuated inflammation. The inflammation resulted in chronic impairment of colonic motility in DSS-WT mice. NPY -treated rat enteric neurons in vitro exhibited increased nitrite and TNF-alpha production.. NPY mediated increase in nNOS is a determinant of oxidative stress and subsequent inflammation. Our study highlights the role of neuronal NPY and nNOS as mediators of inflammatory processes in IBD.

Topics: Animals; Catalase; Colitis; Dextran Sulfate; Disease Models, Animal; Gene Deletion; Glutathione; Inflammation; Inflammatory Bowel Diseases; Mice; Mice, Knockout; Neuropeptide Y; Nitric Oxide Synthase Type I; Nitrites; Oxidative Stress; Peroxidase

Psychological conditions, including stress, compromise immune defenses. Although this concept is not novel, the molecular mechanism behind it remains unclear. Neuropeptide Y (NPY) in the central nervous system is a major regulator of numerous physiological functions, including stress. Postganglionic sympathetic nerves innervating lymphoid organs release NPY, which together with other peptides activate five Y receptors (Y1, Y2, Y4, Y5, and y(6)). Using Y1-deficient (Y1(-/-)) mice, we showed that Y1(-/-) T cells are hyperresponsive to activation and trigger severe colitis after transfer into lymphopenic mice. Thus, signaling through Y1 receptor on T cells inhibits T cell activation and controls the magnitude of T cell responses. Paradoxically, Y1(-/-) mice were resistant to T helper type 1 (Th1) cell-mediated inflammatory responses and showed reduced levels of the Th1 cell-promoting cytokine interleukin 12 and reduced interferon gamma production. This defect was due to functionally impaired antigen-presenting cells (APCs), and consequently, Y1(-/-) mice had reduced numbers of effector T cells. These results demonstrate a fundamental bimodal role for the Y1 receptor in the immune system, serving as a strong negative regulator on T cells as well as a key activator of APC function. Our findings uncover a sophisticated molecular mechanism regulating immune cell functions that can lead to stress-induced immunosuppression.

Topics: Animals; Antigen-Presenting Cells; Autoimmune Diseases; Colitis; Female; Inflammation; Interferon-gamma; Interleukin-12; Lymphocyte Activation; Lymphocyte Count; Lymphoid Tissue; Male; Mice; Mice, Knockout; Neuropeptide Y; Receptors, Neuropeptide Y; Signal Transduction; Stress, Psychological; Sympathetic Fibers, Postganglionic; Th1 Cells

Neuropeptide Y (NPY) is thought to play a crucial role in the normal hypothalamic response to starvation. After a period of food restriction, increased release of NPY induces hunger and hyperphagia, and helps to restore body weight to its set point. Persistent anorexia in rats with experimental colitis implies failure of this adaptive feeding response. In vivo NPY release and regional hypothalamic NPY concentrations were measured in rats with trinitrobenzenesulphonic acid (TNBS)-induced colitis, healthy controls and animals pair-fed to match the food intake of the colitic group. Food intake in the colitic group was assessed after administration of NPY and two other potent orexigenic peptides: melanin-concentrating hormone (MCH) and hypocretin (orexin-A). Food intake was decreased by 30-80% below control values for 5 days in the colitic rats. In both the pair-fed and colitic groups, release of NPY in the paraventricular nucleus was significantly increased compared with free-feeding controls. Intraventricular or intrahypothalamic administration of NPY, MCH or hypocretin elicited a feeding response in healthy controls, but not in the colitic group. In summary, animals with TNBS-colitis and anorexia show an appropriate increase in hypothalamic NPYergic activity. However, the failure of NPY and other orexigenic peptides to increase feeding in the colitic group indicates suppression of feeding, either by inhibition of a common downstream hypothalamic neuronal pathway or by induction of one or more potent anorexigenic agents.

Topics: Adaptation, Physiological; Animals; Anorexia; Blood Glucose; Body Weight; Carrier Proteins; Colitis; Corticosterone; Eating; Hypothalamic Hormones; Hypothalamus; Insulin; Intracellular Signaling Peptides and Proteins; Male; Melanins; Neuropeptide Y; Neuropeptides; Orexins; Pituitary Hormones; Rats; Rats, Wistar; Trinitrobenzenesulfonic Acid

A rat model of colitis [dextran sulfate (DSS)] was used to study the permeation of Evans blue (EB) from the lumen into the wall of proximal and distal colonic loops after exposure to the dye for 2 hr. Topical application of drugs used in human ulcerative colitis (lidocaine, mesalazine, prednisolone, or sucralfate) was given daily during induction of colitis to protect the mucosa. The mucosal changes were evaluated with special regard to peptidergic innervation [substance P (SP) and neuropeptide Y (NPY)], invasion of antigen-presenting polydendritic cells, and mucin-containing goblet cells. DSS-treatment caused a significantly increased permeation of EB. In the proximal loops a significant inhibition was obtained after treatment with lidocaine, prednisolone, or sucralfate. In the distal loops only treatment with lidocaine had a preventive effect. Immunocytochemically there was a clear hyperplasia of both mucosal SP- and NPY-immunoreactive nerve fibers in regions with crypt abnormalities. In these regions also most of the goblet cells were devoid of mucus. Like the changes in permeation, these morphological changes were most prominent in the distal loops. With induction of colitis, the mucosa and lamina propria were invaded by polydendritic cells; the visual score was markedly decreased in the proximal loops treated with lidocaine, prednisolone, or sucralfate. In the distal loops similar effects were obtained after treatment with lidocaine or prednisolone. Prevention of the influx of antigens in both loops after lidocaine treatment with reduced recruitment of polydendritic cells into the lamina propria is suggested. The nerve hyperplasia may thus be secondary to luminal challenge with antigens during induction of colitis. The discrepancy between increased permeation and absence of polydendritic cell response in the distal loops after prednisolone may reflect separate actions of steroids on the intestinal epithelium and the immune cells.

Topics: Administration, Rectal; Aminosalicylic Acids; Anesthetics, Local; Animals; Anti-Inflammatory Agents; Anti-Inflammatory Agents, Non-Steroidal; Anti-Ulcer Agents; Antigen-Presenting Cells; Cell Membrane Permeability; Colitis; Colitis, Ulcerative; Colon; Coloring Agents; Dextran Sulfate; Evans Blue; Humans; Immunohistochemistry; Intestinal Absorption; Intestinal Mucosa; Lidocaine; Male; Mesalamine; Nerve Fibers; Neuropeptide Y; Prednisolone; Rats; Rats, Sprague-Dawley; S100 Proteins; Substance P; Sucralfate