Adenosine 2A receptor contributes to the facilitation of postinfectious irritable bowel syndrome by γδ T cells via the PKA/CREB/NF-κB signaling pathway

BACKGROUND Immunological dysfunction-induced low-grade inflammation is regarded as one of the predominant pathogenetic mechanisms in post-infectious irritable bowel syndrome(PI-IBS).γδT cells play a crucial role in innate and adaptive immunity.Adenosine receptors expressed on the surface ofγδT cells participate in intestinal inflammation and immunity regulation.AIM To investigate the role ofγδT cell regulated by adenosine 2A receptor(A2AR)in PI-IBS.METHODS The PI-IBS mouse model has been established with Trichinella spiralis(T.spiralis)infection.The intestinal A2AR and A2AR inγδT cells were detected by immunohistochemistry,and the inflammatory cytokines were measured by western blot.The role of A2AR on the isolatedγδT cells,including proliferation,apoptosis,and cytokine production,were evaluated in vitro.Their A2AR expression was measured by western blot and reverse transcription polymerase chain reaction(RT-PCR).The animals were administered with A2AR agonist,or A2AR antagonist.Besides,γδT cells were also injected back into the animals,and the parameters described above were examined,as well as the clinical features.Furthermore,the A2AR-associated signaling pathway molecules were assessed by western blot and RT-PCR.RESULTS PI-IBS mice exhibited elevated ATP content and A2AR expression(P<0.05),and suppression of A2AR enhanced PI-IBS clinical characteristics,indicated by the abdominal withdrawal reflex and colon transportation test.PI-IBS was associated with an increase in intestinal T cells,and cytokine levels of interleukin-1(IL-1),IL-6,IL-17A,and interferon-α(IFN-α).Also,γδT cells expressed A2AR in vitro and generated IL-1,IL-6,IL-17A,and IFN-α,which can be controlled by A2AR agonist and antagonist.Mechanistic studies demonstrated that the A2AR antagonist improved the function ofγδT cells through the PKA/CREB/NF-κB signaling pathway.CONCLUSION Our results revealed that A2AR contributes to the facilitation of PI-IBS by regulating the function ofγδT cells via the PKA/CREB/NF-κB signaling pathway.

Attenuation of gastric mucosal inflammation induced by aspirin through activation of A_(2A) adenosine receptor in rats

AIM： To determine whether a specific adenosine A2A receptor agonist （ATL-146e） can ameliorate aspirin-induced gastric mucosal lesions in rats, and reduce neutrophil accumulation and production of pro-inflammatory cytokines. METHODS： Gastric lesions were produced by oral gavage of aspirin （200 mg/kg） and HCI （0.15 mol/L, 8.0 mL/kg）. 4-{3-[6-Amino-9-（5-ethylcarbamoyl-3,4- dihydroxy-tetrahydro-furan-2-yl）-9H-purin-2-yl]-prop-2- ynyl}-cyclohexanecarboxylic acid methyl ester （ATL-146e, 2.5-5μg/kg, IP） was injected 30 min before the administration of aspirin. Tissue myeloperoxidase （MPO） concentration in gastric mucosa was measured as an index of neutrophil infiltration. Gastric mucosal concentrations of tumor necrosis factor-α （TNF-α） and interleukin-1β （IL-1β） were determined by ELISA. Also, we examined the effect of ATL-146e on tissue prostaglandin E2 （PGE2） production and gastric secretion. RESULTS： Intragastric administration of aspirin induced multiple hemorrhagic erosions in rat gastric mucosa. The total length of gastric erosions （ulcer index） in control rats was 29.8±7.75 mm and was reduced to 3.8±1.42 mm alter pretreatment with 5.0 g/kg ATL-146e （P〈 0.01）. The gastric contents of MPO and pro-inflammatory cytokines were all increased after the administration of aspirin and reduced to nearly normal levels by ATL-146e. Gastric mucosal PGE2 concentration was not affected by intraperitoneal injection of ATL-146e. CONCLUSION： The specific adenosine A2A receptor agonist, ATL-146e, has potent anti-ulcer effects presumably mediated by its anti-inflammatory properties.

Upregulated adenosine 2A receptor accelerates post-infectious irritable bowel syndrome by promoting CD4+T cells’T helper 17 polarization

BACKGROUND Post-infectious irritable bowel syndrome(PI-IBS)is generally regarded as a functional disease.Several recent studies have reported the involvement of lowgrade inflammation and immunological dysfunction in PI-IBS.T helper 17(Th17)polarization occurs in IBS.Adenosine and its receptors participate in intestinal inflammation and immune regulation.AIM To investigate the role of Th17 polarization of CD4+T cells regulated by adenosine 2A receptor(A2AR)in PI-IBS.METHODS A PI-IBS model was established by infecting mice with Trichinella spiralis.The intestinal A2AR and CD4+T lymphocytes were detected by immunohistochemistry,and the inflammatory cytokines were detected by enzyme-linked immunoassay.CD4+T lymphocytes present in the animal’s spleen were separated and cultured with or without A2AR agonist and antagonist.Western blotting and real-time quantitative polymerase chain reaction were performed to determine the effect of A2AR on the cells and intestinal tissue.Cytokine production was determined.The protein and mRNA levels of A2AR associated signaling pathway molecules were also evaluated.Furthermore,A2AR agonist and antagonist were injected into the mouse model and the clinical features were observed.RESULTS The PI-IBS mouse model showed increased expression of ATP and A2AR(P<0.05),and inhibition of A2AR improved the clinical features in PI-IBS,including the abdominal withdrawal reflex and colon transportation test(P<0.05).The number of intestinal CD4+T cells and interleukin-17(IL-17)protein levels increased during PI-IBS,which was reversed by administration of the A2AR antagonist(P<0.05).CD4+T cells expressed A2AR and produced IL-17 in vitro,which was regulated by the A2AR agonist and antagonist.The A2AR antagonist increased the production of IL-17 by CD4+T cells via the Janus kinase-signal transducer and activator of transcriptionreceptor-related orphan receptorγsignaling pathway.CONCLUSION The results of the present study suggested that the upregulation of A2AR increases PI-IBS by promoting the Th17 polarization of CD4+T cells.