RESUMO
Lipopolysaccharides (LPS) are potent pro-inflammatory molecules that enter the systemic circulation from the intestinal lumen by uncertain mechanisms. We investigated these mechanisms and the effect of exogenous glucagon-like peptide-2 (GLP-2) on LPS transport in the rodent small intestine. Transmucosal LPS transport was measured in Ussing-chambered rat jejunal mucosa. In anesthetized rats, the appearance of fluorescein isothiocyanate (FITC)-LPS into the portal vein (PV) and the mesenteric lymph was simultaneously monitored after intraduodenal perfusion of FITC-LPS with oleic acid and taurocholate (OA/TCA). In vitro, luminally applied LPS rapidly appeared in the serosal solution only with luminal OA/TCA present, inhibited by the lipid raft inhibitor methyl-ß-cyclodextrin (MßCD) and the CD36 inhibitor sulfosuccinimidyl oleate (SSO), or by serosal GLP-2. In vivo, perfusion of FITC-LPS with OA/TCA rapidly increased FITC-LPS appearance into the PV, followed by a gradual increase of FITC-LPS into the lymph. Rapid PV transport was inhibited by the addition of MßCD or by SSO, whereas transport into the lymph was inhibited by chylomicron synthesis inhibition. Intraveous injection of the stable GLP-2 analog teduglutide acutely inhibited FITC-LPS transport into the PV, yet accelerated FITC-LPS transport into the lymph via Nω-nitro-l-arginine methyl ester (l-NAME)- and PG97-269-sensitive mechanisms. In vivo confocal microscopy in mouse jejunum confirmed intracellular FITC-LPS uptake with no evidence of paracellular localization. This is the first direct demonstration in vivo that luminal LPS may cross the small intestinal barrier physiologically during fat absorption via lipid raft- and CD36-mediated mechanisms, followed by predominant transport into the PV, and that teduglutide inhibits LPS uptake into the PV in vivo.NEW & NOTEWORTHY We report direct in vivo confirmation of transcellular lipopolysaccharides (LPS) uptake from the intestine into the portal vein (PV) involving CD36 and lipid rafts, with minor uptake via the canonical chylomicron pathway. The gut hormone glucagon-like peptide-2 (GLP-2) inhibited uptake into the PV. These data suggest that the bulk of LPS absorption is via the PV to the liver, helping clarify the mechanism of LPS transport into the PV as part of the "gut-liver" axis. These data do not support the paracellular transport of LPS, which has been implicated in the pathogenesis of the "leaky gut" syndrome.
Assuntos
Gorduras/metabolismo , Intestino Delgado/metabolismo , Lipopolissacarídeos/metabolismo , Animais , Transporte Biológico/efeitos dos fármacos , Transporte Biológico/fisiologia , Fármacos Gastrointestinais/farmacologia , Células HEK293 , Humanos , Intestino Delgado/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Peptídeos/química , Peptídeos/farmacologia , Ratos , Ratos Sprague-Dawley , Receptor 4 Toll-Like/genética , Receptor 4 Toll-Like/metabolismoRESUMO
BACKGROUND: Circulating endotoxin (lipopolysaccharide, LPS) increases the gut paracellular permeability. We hypothesized that glucagon-like peptide-2 (GLP-2) acutely reduces LPS-related increased intestinal paracellular permeability by a mechanism unrelated to its intestinotrophic effect. METHODS: We assessed small intestinal paracellular permeability in vivo by measuring the appearance of intraduodenally perfused FITC-dextran 4000 (FD4) into the portal vein (PV) in rats 1-24 h after LPS treatment (5 mg/kg, ip). We also examined the effect of a stable GLP-2 analog teduglutide (TDG) on FD4 permeability. RESULTS: FD4 movement into the PV was increased 6 h, but not 1 or 3 h after LPS treatment, with increased PV GLP-2 levels and increased mRNA expressions of proinflammatory cytokines and proglucagon in the ileal mucosa. Co-treatment with a GLP-2 receptor antagonist enhanced PV FD4 concentrations. PV FD4 concentrations 24 h after LPS were higher than FD4 concentrations 6 h after LPS, reduced by exogenous GLP-2 treatment given 6 or 12 h after LPS treatment. FD4 uptake measured 6 h after LPS was reduced by TDG 3 or 6 h after LPS treatment. TDG-associated reduced FD4 uptake was reversed by the VPAC1 antagonist PG97-269 or L-NAME, not by EGF or IGF1 receptor inhibitors. CONCLUSIONS: Systemic LPS releases endogenous GLP-2, reducing LPS-related increased permeability. The therapeutic window of exogenous GLP-2 administration is at minimum within 6-12 h after LPS treatment. Exogenous GLP-2 treatment is of value in the prevention of increased paracellular permeability associated with endotoxemia.
Assuntos
Endotoxemia/prevenção & controle , Peptídeo 2 Semelhante ao Glucagon/metabolismo , Receptor do Peptídeo Semelhante ao Glucagon 2/agonistas , Absorção Intestinal/efeitos dos fármacos , Intestino Delgado/efeitos dos fármacos , Peptídeos/farmacologia , Animais , Dextranos/sangue , Modelos Animais de Doenças , Endotoxemia/sangue , Endotoxemia/induzido quimicamente , Fluoresceína-5-Isotiocianato/análogos & derivados , Receptor do Peptídeo Semelhante ao Glucagon 2/metabolismo , Mediadores da Inflamação/metabolismo , Intestino Delgado/metabolismo , Lipopolissacarídeos , Masculino , Permeabilidade , Veia Porta , Ratos Sprague-Dawley , Fatores de TempoRESUMO
Salusin-ß is an endogenous bioactive peptide that was identified in a human full-length enriched cDNA library using bioinformatics analyses. In our previous study, we found that synthetic salusin-ß exhibits antibacterial activity against only Gram-positive microorganisms such as Staphylococcus aureus NBRC 12732. Salusin-ß has an ability to depolarize the cytoplasmic membrane of this bacterium, and this phenomenon may be linked to the antibacterial activity of this peptide. A cell-penetrating peptide (CPP), human immunodeficiency virus (HIV)-1 transactivator of transcription (Tat) (49-57) is a short cationic peptide that can traverse cell membranes. In this report, synthetic peptide conjugates of salusin-ß and HIV-1 Tat(49-57) showed potent antibacterial activities against both Gram-positive Staphylococcus aureus NBRC 12732 and Gram-negative Escherichia coli NBRC 12734. The synthetic peptides also depolarized the cytoplasmic membrane of Escherichia coli NBRC 12734 as well as Staphylococcus aureus NBRC 12732. These results suggested that HIV-1 Tat(49-57) is a protein transduction domain or CPP that changes the interaction mode between salusin-ß and the cell membrane of Escherichia coli NBRC 12734. By binding to HIV-1 Tat(49-57), salusin-ß showed a broad antibacterial spectrum regardless of whether the target was a Gram-positive or Gram-negative bacterium.
Assuntos
Antibacterianos/síntese química , Peptídeos e Proteínas de Sinalização Intercelular/química , Peptídeos/química , Produtos do Gene tat do Vírus da Imunodeficiência Humana/química , Sequência de Aminoácidos , Antibacterianos/química , Antibacterianos/farmacologia , Membrana Celular/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , HIV-1/metabolismo , Humanos , Testes de Sensibilidade Microbiana , Peptídeos/síntese química , Peptídeos/farmacologia , Staphylococcus aureus/efeitos dos fármacosRESUMO
Urine concentration (condensation) leads to the inactivation of pathogens in urine owing to a hyperosmotic environment. This study proposed an inactivation kinetic model of Escherichia coli (E. coli), a surrogate of human bacterial pathogens, in concentrated synthetic urine. The model parameters were obtained under an assumption that the inactivation rate of E. coli followed a binomial distribution, which made it possible to accurately simulate the time-course decay of E. coli in synthetic urine. The inactivation rate constant values obtained in concentrated urine samples, ammonium buffer solutions and carbonate buffer solutions indicated that the osmotic pressure was a relatively predominant cause for the inactivation of E. coli. The appropriate storage time was estimated using the approach of quantitative microbial risk assessment, which indicated that the 5-fold concentrated urine could be safely collected after 1-day storage when urea was hydrolyzed, whereas 91-hour storage was required for non-concentrated urine. The occupational risk was not negligible even with 6-month storage at 20 °C when urea was not hydrolyzed, which suggested that the urine storage styles should be clarified more minutely. The present study highlights the importance of "predictive environmental microbiology," which deals with inactivation kinetic models of microorganisms under varied environmental conditions to fully implement the hazard analysis and critical control point (HACCP) approach for the safe use of human excreta in agriculture.
Assuntos
Escherichia coli , Saneamento , Microbiologia Ambiental , Microbiologia de Alimentos , Humanos , Cinética , TemperaturaRESUMO
Xenin-25 is a neurotensin-like peptide that is secreted by enteroendocrine cells in the small intestine. Xenin-8 is reported to augment duodenal anion secretion by activating afferent neural pathways. The intrinsic neuronal circuits mediating the xenin-25-induced anion secretion were characterized using the Ussing-chambered, mucosa-submucosa preparation from the rat ileum. Serosal application of xenin-25 increased the short-circuit current in a concentration-dependent manner. The responses were abolished by the combination of Cl--free and HCO3- -free solutions. The responses were almost completely blocked by TTX (10-6 M) but not by atropine (10-5 M) or hexamethonium (10-4 M). The selective antagonists for neurotensin receptor 1 (NTSR1), neurokinin 1 (NK1), vasoactive intestinal polypeptide (VIP) receptors 1 and 2 (VPAC1 and VPAC2, respectively), and capsaicin, but not 5-hydroxyltryptamine receptors 3 and 4 (5-HT3 and 5-HT4), NTSR2, and A803467, inhibited the responses to xenin-25. The expression of VIP receptors (Vipr) in rat ileum was examined using RT-PCR. The Vipr1 PCR products were detected in the submucosal plexus and mucosa. Immunohistochemical staining showed the colocalization of NTSR1 and NK1 with substance P (SP)- and calbindin-immunoreactive neurons in the submucosal plexus, respectively. In addition, NK1 was colocalized with noncholinergic VIP secretomotor neurons. Based on the results from the present study, xenin-25-induced Cl-/ HCO3- secretion is involved in NTSR1 activation on intrinsic and extrinsic afferent neurons, followed by the release of SP and subsequent activation of NK1 expressed on noncholinergic VIP secretomotor neurons. Finally, the secreted VIP may activate VPAC1 on epithelial cells to induce Cl-/ HCO3- secretion in the rat ileum. Activation of noncholinergic VIP secretomotor neurons by intrinsic primary afferent neurons and extrinsic afferent neurons by postprandially released xenin-25 may account for most of the neurogenic secretory response induced by xenin-25. NEW & NOTEWORTHY This study is the first to investigate the intrinsic neuronal circuit responsible for xenin-25-induced anion secretion in the rat small intestine. We have found that nutrient-stimulated xenin-25 release may activate noncholinergic vasoactive intestinal polypeptide (VIP) secretomotor neurons to promote Cl-/ HCO3- secretion through the activation of VIP receptor 1 on epithelial cells. Moreover, the xenin-25-induced secretory responses are mainly linked with intrinsic primary afferent neurons, which are involved in the activation of neurotensin receptor 1 and neurokinin 1 receptor.
Assuntos
Ânions/metabolismo , Sistema Nervoso Entérico/metabolismo , Íleo , Vias Neurais/metabolismo , Neurotensina/metabolismo , Receptores Tipo I de Polipeptídeo Intestinal Vasoativo/metabolismo , Animais , Hormônios Gastrointestinais/metabolismo , Íleo/inervação , Íleo/fisiologia , Mucosa Intestinal/metabolismo , Ratos , Receptores de Neurotensina/metabolismoRESUMO
Infection is a major cause of mortality in chronic kidney disease (CKD) patients. Although immune dysfunction is a risk factor for infection in CKD patients, its causes are not fully elucidated. In the present study, we evaluated whether p-cresyl sulfate (pCS), an intestinal bacteria-derived uremic toxin, was involved in immune dysfunction in CKD. We used osmotic pumps to establish adenine-induced renal dysfunction mice with a chronically high blood pCS concentration. Analysis of lymphocyte subsets revealed that pCS significantly reduced peripheral B cells in renal dysfunction mice. In vitro, pCS inhibited interleukin (IL)-7-induced proliferation of CD43+ B-cell progenitors and suppressed IL-7-induced phosphorylation of signal transducer and activator of transcription 5 (STAT5) in these cells. Cell cycle analysis showed that pCS significantly decreased the percentage of CD43+ B-cell progenitors in S phase and increased that in G1 phase. These results suggest that pCS suppressed IL-7-induced STAT5 signaling and inhibited B-cell progenitor proliferation, leading to reduction of peripheral B cells in adenine-induced renal dysfunction mice. Therefore, pCS decreases peripheral B cells by inhibiting proliferation of CD43+ B-cell progenitors and is a likely cause of immune dysfunction in CKD patients.
Assuntos
Adenina/toxicidade , Linfócitos B/patologia , Cresóis/toxicidade , Insuficiência Renal Crônica/induzido quimicamente , Insuficiência Renal Crônica/patologia , Ésteres do Ácido Sulfúrico/toxicidade , Animais , Linfócitos B/efeitos dos fármacos , Linfócitos B/imunologia , Células da Medula Óssea/efeitos dos fármacos , Células da Medula Óssea/imunologia , Células da Medula Óssea/patologia , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/fisiologia , Relação Dose-Resposta a Droga , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Insuficiência Renal Crônica/imunologiaRESUMO
Xenin-25, a neurotensin (NT)-related anorexigenic gut hormone generated mostly in the duodenal mucosa, is believed to increase the rate of duodenal ion secretion, because xenin-induced diarrhea is not present after Roux-en-Y gastric bypass surgery. Because the local effects of xenin on duodenal ion secretion have remained uninvestigated, we thus examined the neural pathways underlying xenin-induced duodenal anion secretion. Intravenous infusion of xenin-8, a bioactive C-terminal fragment of xenin-25, dose dependently increased the rate of duodenal HCO3- secretion in perfused duodenal loops of anesthetized rats. Xenin was immunolocalized to a subset of enteroendocrine cells in the rat duodenum. The mRNA of the xenin/NT receptor 1 (NTS1) was predominantly expressed in the enteric plexus, nodose and dorsal root ganglia, and in the lamina propria rather than in the epithelium. The serosal application of xenin-8 or xenin-25 rapidly and transiently increased short-circuit current in Ussing-chambered mucosa-submucosa preparations in a concentration-dependent manner in the duodenum and jejunum, but less so in the ileum and colon. The selective antagonist for NTS1, substance P (SP) receptor (NK1), or 5-hydroxytryptamine (5-HT)3, but not NTS2, inhibited the responses to xenin. Xenin-evoked Cl- secretion was reduced by tetrodotoxin (TTX) or capsaicin-pretreatment, and abolished by the inhibitor of TTX-resistant sodium channel Nav1.8 in combination with TTX, suggesting that peripheral xenin augments duodenal HCO3- and Cl- secretion through NTS1 activation on intrinsic and extrinsic afferent nerves, followed by release of SP and 5-HT. Afferent nerve activation by postprandial, peripherally released xenin may account for its secretory effects in the duodenum.
Assuntos
Duodeno/efeitos dos fármacos , Duodeno/metabolismo , Neurônios Aferentes/efeitos dos fármacos , Neurônios Aferentes/metabolismo , Neurotensina/farmacologia , Vias Aferentes/efeitos dos fármacos , Vias Aferentes/metabolismo , Animais , Relação Dose-Resposta a Droga , Hormônios Gastrointestinais/farmacologia , Mucosa Intestinal/efeitos dos fármacos , Mucosa Intestinal/metabolismo , Masculino , Vias Neurais/efeitos dos fármacos , Vias Neurais/metabolismo , Técnicas de Cultura de Órgãos , Ratos , Ratos Sprague-DawleyRESUMO
Protein fermentation by intestinal bacteria generates various compounds that are not synthesized by their hosts. An example is p-cresol, which is produced from tyrosine. Patients with chronic kidney disease (CKD) accumulate high concentrations of intestinal bacteria-derived p-cresyl sulfate (pCS), which is the major metabolite of p-cresol, in their blood, and this accumulation contributes to certain CKD-associated disorders. Immune dysfunction is a CKD-associated disorder that frequently contributes to infectious diseases among CKD patients. Although some studies imply pCS as an etiological factor, the relation between pCS and immune systems is poorly understood. In the present study, we investigated the immunological effects of pCS derived from intestinal bacteria in mice. For this purpose, we fed mice a tyrosine-rich diet that causes the accumulation of pCS in their blood. The mice were shown to exhibit decreased Th1-driven 2, 4-dinitrofluorobenzene-induced contact hypersensitivity response. The concentration of pCS in blood was negatively correlated with the degree of the contact hypersensitivity response. In contrast, the T cell-dependent antibody response was not influenced by the accumulated pCS. We also examined the in vitro cytokine responses by T cells in the presence of pCS. The production of IFN-γ was suppressed by pCS. Further, pCS decreased the percentage of IFN-γ-producing Th1 cells. Our results suggest that intestinal bacteria-derived pCS suppressesTh1-type cellular immune responses.
Assuntos
Bactérias/metabolismo , Cresóis/sangue , Sistema Imunitário/microbiologia , Intestinos/microbiologia , Ésteres do Ácido Sulfúrico/sangue , Células Th1/imunologia , Animais , Linfócitos T CD8-Positivos/imunologia , Dermatite de Contato/imunologia , Dermatite de Contato/patologia , Dinitrofluorbenzeno/efeitos adversos , Feminino , Interações Hospedeiro-Patógeno , Imunidade Celular/efeitos dos fármacos , Interferon gama/biossíntese , Interferon gama/sangue , Mucosa Intestinal/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Células Th1/efeitos dos fármacos , Tirosina/administração & dosagemRESUMO
Salusin-ß has been detected in numerous mammalian tissues and has been shown to have various effects on the cardiovascular system. In this study, we showed that salusin-ß exhibited potent antibacterial activity against Gram-positive microorganisms such as Bacillus subtilis NBRC 3513, Bacillus megaterium ATCC 19213, Staphylococcus aureus NBRC 12732, and Staphylococcus epidermidis NBRC 12933. A cytoplasmic membrane-depolarizing assay using the DiSC3(5) dye revealed that the addition of 4 nmol/mL of salusin-ß caused the leakage of fluorescence dye from Staphylococcus aureus NBRC 12732. The antimicrobial potency and circular dichroism (CD) spectroscopy of five analogs related to salusin-ß were examined to determine structure-function relationships in its N- and C-terminal regions. The results obtained suggest that the N-terminal sequences of the salusin-ß molecule are important for the expression of the potent antimicrobial activity of this peptide. A profile corresponding to that of the α-helix conformation was observed in the salusin-ß solution.
Assuntos
Bactérias Gram-Positivas/efeitos dos fármacos , Peptídeos e Proteínas de Sinalização Intercelular/farmacologia , Relação Dose-Resposta a Droga , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/química , Testes de Sensibilidade Microbiana , Conformação Proteica , Relação Estrutura-AtividadeRESUMO
Soy foods are known to be effective for breast cancer prevention. The habitual consumption of soy isoflavones in combination with the probiotic Lactobacillus casei Shirota (LcS) was shown to decrease the risk of breast cancer occurrence in our previous population-based case-controlled study among Japanese women. The present study aimed to elucidate the cooperative prevention mechanism of soymilk and LcS using an animal carcinogenic model. Female Sprague-Dawley rats received a high-fat, AIN-76A diet containing soymilk, LcS, both soymilk and LcS, or none and were orally exposed to 2-amino-1-methyl-6-penylimidazo[4,5-b]pyridine at a dose of 85 mg/kg bodyweight eight times for 2 weeks. The development of palpable mammary tumors was monitored for 17 weeks. Tumor tissues were immunohistochemically examined for estrogen receptor (ER)-α, Ki-67 and CD34. Compared with the control group, the incidence and multiplicity of mammary tumors were reduced by soymilk alone and soymilk in combination with LcS, while tumor volume was decreased by LcS alone and LcS in combination with soymilk. An immunohistochemical analysis revealed that soymilk in combination with LcS more effectively reduced the numbers of ER-α-positive and Ki-67-positive cells in tumors than soymilk alone and that both soymilk and LcS inhibited tumor angiogenesis. These results demonstrated that soymilk prevents the development of mammary tumors and that LcS suppresses tumor growth, potentially enhancing the preventive efficacy of soymilk. The habitual consumption of LcS in combination with soymilk might be a beneficial dietary style for breast cancer prevention.
Assuntos
Anticarcinógenos/administração & dosagem , Lacticaseibacillus casei/fisiologia , Neoplasias Mamárias Experimentais/prevenção & controle , Probióticos/administração & dosagem , Leite de Soja/administração & dosagem , Animais , Feminino , Imidazóis , Antígeno Ki-67/metabolismo , Fígado/patologia , Neoplasias Mamárias Experimentais/irrigação sanguínea , Neoplasias Mamárias Experimentais/induzido quimicamente , Neovascularização Patológica/prevenção & controle , Tamanho do Órgão , Ratos , Ratos Sprague-Dawley , Receptores de Estrogênio/metabolismo , Baço/patologiaRESUMO
Guava leaf tea (GLT) contains guava leaf polyphenol (Gvpp), which regulates the absorption of dietary carbohydrate from the intestines. Borderline diabetics, who are at high risk of development of diabetes, take GLT to suppress a rapid increase of blood sugar level after meals. However, patients with diabetes in whom diabetic drugs or warfarin as a blood thinner are prescribed also take GLT with the expectation of glycemic control. Therefore, we studied whether GLT had potential for inhibition or induction of cytochrome P450 (CYP) and an influence on the action of warfarin. Extract of guava leaf (GvEx) consists of carbohydrate and polyphenols, which are Gvpp, quercetin, and ellagic acid. These polyphenols, but not GvEx, showed a certain level of inhibition of human-cDNA-expressed CYPs. In a comparison of GLT and grapefruit juice, GLT showed weaker inhibition of CYP activities and of midazolam 1'-hydroxylation than grapefruit juice. Furthermore, neither liver weight nor CYP3A expression in the liver was changed in rats that received GvEx for 90 days compared with the control group. When rats were concomitantly treated with GLT and warfarin, the prolongation of clotting time of blood by warfarin was not influenced. These data suggest that GLT is unlikely to interact with drugs.
Assuntos
Inibidores do Citocromo P-450 CYP3A , Interações Alimento-Droga , Polifenóis/farmacologia , Psidium/química , Varfarina/farmacologia , Animais , Bebidas , Citocromo P-450 CYP3A/metabolismo , Inibidores Enzimáticos/farmacologia , Humanos , Fígado/efeitos dos fármacos , Fígado/enzimologia , Masculino , Midazolam/metabolismo , Tempo de Tromboplastina Parcial , Ratos , Ratos Sprague-DawleyRESUMO
Introduction: Physical activity is recommended as an alternative treatment for depression. Myokines, which are secreted from skeletal muscles during physical activity, play an important role in the skeletal muscle-brain axis. Musclin, a newly discovered myokine, exerts physical endurance, however, the effects of musclin on emotional behaviors, such as depression, have not been evaluated. This study aimed to access the anti-depressive effect of musclin and clarify the connection between depression-like behavior and hypothalamic neuropeptides in mice. Methods: We measured the immobility time in the forced swim (FS) test, the time spent in open arm in the elevated-plus maze (EPM) test, the mRNA levels of hypothalamic neuropeptides, and enumerated the c-Fos-positive cells in the paraventricular nucleus (PVN), arcuate nucleus (ARC), and nucleus tractus solitarii (NTS) in mice with the intraperitoneal (i.p.) administration of musclin. Next, we evaluated the effects of a selective corticotropin-releasing factor (CRF) type 1 receptor antagonist, selective CRF type 2 receptor antagonist, melanocortin receptor (MCR) agonist, and selective melanocortin 4 receptor (MC4R) agonist on changes in behaviors induced by musclin. Finally we evaluated the antidepressant effect of musclin using mice exposed to repeated water immersion (WI) stress. Results: We found that the i.p. and i.c.v. administration of musclin decreased the immobility time and relative time in the open arms (open %) in mice and increased urocortin 2 (Ucn 2) levels but decreased proopiomelanocortin levels in the hypothalamus. The numbers of c-Fos-positive cells were increased in the PVN and NTS but decreased in the ARC of mice with i.p. administration of musclin. The c-Fos-positive cells in the PVN were also found to be Ucn 2-positive. The antidepressant and anxiogenic effects of musclin were blocked by central administration of a CRF type 2 receptor antagonist and a melanocortin 4 receptor agonist, respectively. Peripheral administration of musclin also prevented depression-like behavior and the decrease in levels of hypothalamic Ucn 2 induced by repeated WI stress. Discussion: These data identify the antidepressant effects of musclin through the activation of central Ucn 2 signaling and suggest that musclin and Ucn 2 can be new therapeutic targets and endogenous peptides mediating the muscle-brain axis.
Assuntos
Hormônio Liberador da Corticotropina , Urocortinas , Camundongos , Masculino , Animais , Hormônio Liberador da Corticotropina/genética , Urocortinas/farmacologia , Depressão/prevenção & controle , Receptor Tipo 4 de Melanocortina , Hipotálamo/metabolismo , Núcleo Solitário/metabolismo , Antidepressivos/farmacologia , Proteínas Proto-Oncogênicas c-fosRESUMO
Increasing endogenous secretion of glucagonlike peptide (GLP)1 is considered a promising therapeutic approach for type 2 diabetes because decreased GLP1 plasma concentrations have been observed in patients with this condition. Nesfatin1, which is a central and peripheral anorexigenic peptide, has been reported to release GLP1 from enteroendocrine STC1 cells, although whether nesfatin1 stimulates GLP1 secretion in vivo remains to be elucidated. Previous studies have indicated that nesfatin1 has glucoselowering and insulinotropic effects in mice and rats; however, the in vivo mechanism remains unclear. The present study aimed to investigate whether peripheral administration of nesfatin1 increased blood concentrations of GLP1 and insulin in fooddeprived mice. Nesfatin1 was administered intraperitoneally to 18h fasted mice. Plasma GLP1 and insulin concentrations in the mice administered 2.5 µmol/kg nesfatin1 were higher than those in salinetreated mice. Blood glucose concentrations in mice treated with 1.25 and 2.5 µmol/kg nesfatin1 were lower than those in salinetreated mice. The mRNA expression of preproglucagon in mouse ilea after treatment with 1.25 µmol/kg nesfatin1 was higher than that in salinetreated mice. The administration of 1.25 µmol/kg nesfatin1 raised GLP1 concentrations at 30 and 60 min and insulin concentrations at 30 and 60 min after injection. Furthermore, the higher level of nesfatin1induced insulin was diminished by preadministration of antiGLP1 antiserum. Intraperitoneally administered nesfatin1 increased insulin concentrations by accelerating GLP1 secretion. The results are the first in vivo demonstration of promotion of GLP1 secretion by nesfatin1 in the mouse, suggesting the developmental potential of nesfatin1 for GLP1 release.
Assuntos
Diabetes Mellitus Tipo 2 , Peptídeo 1 Semelhante ao Glucagon , Camundongos , Ratos , Animais , Diabetes Mellitus Tipo 2/metabolismo , Células Enteroendócrinas , Insulina/metabolismo , Glucose/metabolismo , Glicemia/metabolismoRESUMO
The present study tried to clarify if mumefural would prevent hyperglycemia, one of the typical symptoms of type 2 diabetes mellitus (T2DM), since mumefural is an extract from Japanese apricots preventing hyperglycemia. To clarify if mumefural would prevent T2DM pathogenesis, we used Otsuka Long-Evans Tokushima fatty (OLETF) rats, T2DM model. Mumefural diminished hyperglycemia, HOMA-IR and plasma triglyceride concentration in OLETF rats under fasting conditions. In addition, mumefural elevated protein expression of sodium-coupled monocarboxylate transporter 1 (SMCT1) in the distal colon participating in absorption of weak organic acids, which behave as bases but not acids after absorption into the body. Mumefural also increased the interstitial fluid pH around the brain hippocampus lowered in OLETF rats compared with non-T2DM LETO rats used as control for OLETF rats. Amyloid-beta accumulation in the brain decreased in accordance with the pH elevation. On the one hand, mumefural didn't affect plasma concentrations of glucagon, GLP-1, GIP or PYY under fasting conditions. Taken together, these observations indicate that: 1) mumefural would be a useful functional food improving hyperglycemia, insulin resistance and the lowered interstitial fluid pH in T2DM; 2) the interstitial fluid pH would be one of key factors influencing the accumulation of amyloid-beta.
Assuntos
Diabetes Mellitus Tipo 2 , Hiperglicemia , Resistência à Insulina , Ratos , Animais , Ratos Endogâmicos OLETF , Glicemia/metabolismo , Insulina , Líquido Extracelular/metabolismo , Encéfalo/metabolismo , Concentração de Íons de HidrogênioRESUMO
Real-time measurements for gut motility in conscious rats or mice combined with intracerebroventricular or intravenous injection of peptide agonists or antagonists allow us to understand the regulatory mechanism of gastrointestinal motility. Neuropeptide Y (NPY) in the arcuate nucleus in the hypothalamus stimulates the fasted motility in the duodenum, while urocortin in the paraventricular nucleus inhibits fed and fasted motility in the antrum and duodenum. Acyl ghrelin exerts stimulatory effects on the motility of the antrum and duodenum in both the fed and fasted state of animals. NPY Y2 and Y4 receptors in the brain may mediate the action of acyl ghrelin, and vagal afferent pathways might be involved in this mechanism. Des-acyl ghrelin exerts inhibitory effects on the motility of the antrum but not on the motility of the duodenum in the fasted state of animals. CRF type 2 receptor in the brain may mediate the action of des-acyl ghrelin, and vagal afferent pathways might not be involved in this mechanism. Obestatin exerts inhibitory effects on the motility of the antrum and duodenum in the fed state but not in the fasted state of animals. CRF type 1 and type 2 receptors in the brain may mediate the action of obestatin, and vagal afferent pathways might be partially involved in this mechanism.
Assuntos
Motilidade Gastrointestinal/fisiologia , Grelina/fisiologia , Neuropeptídeo Y/fisiologia , Urocortinas/fisiologia , Animais , Duodeno/fisiologia , Camundongos , RatosRESUMO
BACKGROUND: Previous studies have shown that administration of ghrelin exhibits protective and therapeutic effects in the gut. The aim of the present investigation was to examine the influence of ghrelin administration on the course of cysteamine-induced duodenal ulcers, as well as effects on mucosal production of oxygen free radicals and duodenal antioxidant defense. MATERIAL/METHODS: Duodenal ulcers were induced in male Wistar rats by cysteamine administered intragastrically at the dose of 200 mg/kg in 1 ml of saline, 3 times at 4-h intervals. Starting 24 h after the first dose of cysteamine, rats were treated intraperitoneally twice a day with saline or ghrelin given at the dose of 4, 8 or 16 nmol/kg/dose. Seven days after administration of the first dose of cysteamine, the study was terminated. RESULTS: Induction of ulcers by cysteamine was accompanied by a reduction in duodenal blood flow, mucosal DNA synthesis and mucosal activity of superoxide dismutase (SOD); whereas mucosal concentration of interleukin-1ß and malonyldialdehyde (MDA - an index of lipid peroxidation) were increased. Treatment with ghrelin increased healing rate of duodenal ulcers and enhanced duodenal blood flow, mucosal DNA synthesis and mucosal activity of SOD, and reduced mucosal concentration of interleukin-1ß and MDA. CONCLUSIONS: Treatment with ghrelin increases the healing rate of duodenal ulcers and this effect is related, at least in part, to improvement of duodenal mucosal blood flow, mucosal cell proliferation and antioxidant defense, as well as being related to reduction in mucosal oxidative stress and inflammatory response.
Assuntos
Cisteamina/efeitos adversos , Úlcera Duodenal/tratamento farmacológico , Grelina/administração & dosagem , Cicatrização/efeitos dos fármacos , Animais , Grelina/farmacologia , Grelina/uso terapêutico , Masculino , Ratos , Ratos WistarRESUMO
CONTEXT: It is of great importance to evaluate the safety of probiotics in dysregulated immune conditions, as probiotics can possibly modulate immune functions in the host. OBJECTIVE: We tried to confirm the safety of using Lactobacillus casei strain Shirota (LcS) to help prevent autoimmunity in the central nervous system. METHODS: We used two chronic experimental autoimmune encephalomyelitis (EAE) models, a relapse and remission type EAE model in SJL/J mice and a durable type model in C57BL/6 mice. LcS was administered from 1 week before antigen sensitization until the end of the experiments, and neurological symptoms and histopathological changes of the spinal cord were observed. Immunological parameters were also examined in the SJL/J mouse model. RESULTS: LcS administration did not exacerbate neurological symptoms or histopathological changes of the spinal cord in either model but instead tended to improve neurological symptoms in the SJL/J mouse EAE model. LcS administration transiently upregulated IL-17 production by antigen-stimulated lymphocytes of draining lymph nodes 7 days after sensitization. Enhanced production of IL-10 and an increase in the percentage of CD4(+)CD25(+) T regulatory cells were also observed at the same sites. Strong expression of IL-17 mRNA was detected in the spinal cord of mice that displayed severe neurological symptoms on day 12, but this expression was not enhanced by LcS administration. CONCLUSION: These results demonstrate that LcS does not exacerbate, but instead may improve EAE depending on the immunization conditions, and that IL-17 responses at peripheral sites may not always result in a worsening of autoimmune diseases.
Assuntos
Encefalomielite Autoimune Experimental/imunologia , Interleucina-17/imunologia , Lacticaseibacillus casei , Probióticos/farmacologia , Linfócitos T Reguladores/imunologia , Regulação para Cima/imunologia , Animais , Encefalomielite Autoimune Experimental/patologia , Feminino , Interleucina-10/imunologia , Camundongos , Linfócitos T Reguladores/patologiaRESUMO
Rubiscolin6 is a foodderived opioid peptide found in Spinacia oleracea that has antinociceptive, memoryenhancing, anxiolyticlike and antidepressant effects. Rubiscolin6 has been reported to have two opposing effects on food intake. Food intake is closely connected to gut motility; however, to the best of our knowledge, the effect of rubiscolin6 on gut motility has not been reported. The present study aimed to investigate the effect of rubiscolin6 on postprandial motility of the gastric antrum in conscious mice. A catheter was implanted in the gastric antrum of male C57BL/6J mice. Manometric measurements were performed in fasted male mice and chow was then provided to assess motility in the fed state. Rubiscolin6, the δopioid receptor antagonist naltrindole, a mixture of rubiscolin6 and naltrindole, or vehicle was administered intraperitoneally 30 min after eating. The percentage motor index (%MI) was then calculated. Cumulative food intake was measured in both ad libitumfed and overnightfasted mice. The %MI was significantly lower in mice treated with rubiscolin6 compared with that in the other groups, but normalized by treatment with the rubiscolin6/naltrindole mixture. The decrease in %MI induced by rubiscolin6 remained for 1 h after administration. Cumulative food intake was significantly higher 4 and 6 h after rubiscolin6 administration in ad libitumfed mice but was normalized by the rubiscolin6/naltrindole mixture. Food intake 30 min after rubiscolin6 administration was normal, but was higher in mice treated with the rubiscolin6/naltrindole mixture. Thus, rubiscolin6 may have a rapid effect to reduce postprandial antral motility and may subsequently increase food intake after this inhibitory effect disappears. These effects were revealed to be mediated through δopioid receptors. The orexigenic effect of rubiscolin6 may be applicable to the treatment of anorexia and cachexia.
Assuntos
Ansiolíticos , Antro Pilórico , Animais , Ansiolíticos/farmacologia , Ingestão de Alimentos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Antagonistas de Entorpecentes/farmacologia , Peptídeos Opioides/farmacologia , Fragmentos de Peptídeos , Receptores Opioides , Ribulose-Bifosfato CarboxilaseRESUMO
AIM: Serum adiponectin levels are decreased in patients with cerebral infarction. Adiponectin in circulation exists in three isoforms: high molecular weight (HMW), medium molecular weight (MMW), and low molecular weight (LMW) adiponectin. We measured serum levels of total adiponectin and adiponectin multimers (HMW, MMW, and LMW) in patients with cerebral infarction and compared the serum levels of the three adiponectin multimers in stroke subtypes. We also evaluated the clinical value of adiponectin multimer levels as a biomarker for cerebral infarction. METHODS: We assessed a total of 132 patients with cerebral infarctions. The serum levels of total and adiponectin multimers were measured using enzyme-linked immunosorbent assay (ELISA). RESULTS: The total and HMW adiponectin levels were significantly lower in atherothrombotic infarction (AI) than in cerebral embolism (CE) (total, p < 0.05; HMW, p < 0.05). In male patients, the MMW adiponectin level was significantly lower in the lacunar infarction (LI) group than in the AI group (p < 0.05). The LMW adiponectin level was significantly lower in the AI group than in the LI and CE groups (LI, p < 0.001; CE, p = 0.001). However, there were no significant differences in adiponectin multimer levels among the stroke subtypes in female subjects. Additionally, in female patients with AI and LI, the LMW adiponectin levels were negatively associated with C-reactive protein (CRP; AI, p < 0.05; LI, p < 0.05). CONCLUSION: These findings suggest that a decrease in adiponectin is associated with AI and that serum LMW adiponectin level represents a potential biomarker for AI.
Assuntos
Adiponectina/sangue , Adiponectina/metabolismo , Infarto Cerebral/sangue , Infarto Cerebral/metabolismo , Idoso , Biomarcadores/sangue , Biomarcadores/metabolismo , Proteína C-Reativa/metabolismo , Feminino , Humanos , Masculino , Peso Molecular , Sobrepeso/sangue , Sobrepeso/metabolismo , Isoformas de Proteínas/sangue , Isoformas de Proteínas/metabolismo , Acidente Vascular Cerebral/sangue , Acidente Vascular Cerebral/metabolismoRESUMO
The inhibitory action of the secondary bile acid lithocholic acid (LCA) on neurally evoked Cl-/HCO3- secretion was investigated using the Ussing-chambered mucosal-submucosal preparation from the rat distal colon. Electrical field stimulation (EFS) evoked cholinergic and noncholinergic secretory responses in the rat distal colon. The responses were almost completely blocked by TTX (10-6 M) but not atropine (10-5 M) or hexamethonium (10-4 M). The selective antagonist for VIP receptor 1 (VPAC1) greatly reduced the EFS-evoked response. Thus, the rat distal colon may be predominantly innervated by noncholinergic VIP secretomotor neurons. Basolateral addition of 6 × 10-5 M LCA inhibited the EFS-evoked response. The inhibitory action of LCA was partly rescued by the Y2R antagonist BIIE0246. The bile acid receptor TGR5 agonist INT-777 mimicked the LCA-induced inhibitory action. Immunohistochemical staining showed the colocalization of TGR5 and PYY on L cells. TGR5 immunoreactivity was also found in VIP-immunoreactive submucosal neurons which also expressed the PYY receptor, Y2R. These results suggest that LCA inhibits neurally evoked Cl-/HCO3- secretion through the activation of TGR5 on L cells and cholinergic- and VIP-secretomotor neurons in the submucosal plexus. Furthermore, the inhibitory mechanism may involve TGR5-stimulated PYY release from L cells and Y2R activation in VIP-secretomotor neurons.