STING activation in alveolar macrophages and group 2 innate lymphoid cells suppresses IL-33-driven type 2 immunopathology.

2'3'-cGAMP is known as a nonclassical second messenger and small immune modulator that possesses potent antitumor and antiviral activities via inducing the stimulator of IFN genes-mediated (STING-mediated) signaling pathway. However, its function in regulating type 2 immune responses remains unknown. Therefore, we sought to determine a role of STING activation by 2'3'-cGAMP in type 2 inflammatory reactions in multiple mouse models of eosinophilic asthma. We discovered that 2'3'-cGAMP administration strongly attenuated type 2 lung immunopathology and airway hyperreactivity induced by IL-33 and a fungal allergen, Aspergillus flavus. Mechanistically, upon the respiratory delivery, 2'3'-cGAMP was mainly internalized by alveolar macrophages, in which it activated the STING/IFN regulatory factor 3/type I IFN signaling axis to induce the production of inhibitory factors containing IFN-α, which blocked the IL-33-mediated activation of group 2 innate lymphoid (ILC2) cells in vivo. We further demonstrated that 2'3'-cGAMP directly suppressed the proliferation and function of both human and mouse ILC2 cells in vitro. Taken together, our findings suggest that STING activation by 2'3'-cGAMP in alveolar macrophages and ILC2 cells can negatively regulate type 2 immune responses, implying that the respiratory delivery of 2'3'-cGAMP might be further developed as an alternative strategy for treating type 2 immunopathologic diseases such as eosinophilic asthma.

pH-Dependent 5-Aminosalicylates Releasing Preparations Do Not Affect Thiopurine Metabolism.

BACKGROUND/AIMS: Thiopurines are key drugs in maintenance therapy for treating inflammatory bowel disease (IBD). Time-dependent 5-aminosalicylates (5-ASA) releasing preparations (time-dependent 5-ASA) increase 6-thioguanine nucleotide (6-TGN), an active metabolite of thiopurines. However, the effects of pH-dependent 5-ASA releasing preparations (pH-dependent 5-ASA) on thiopurine metabolism were not reported. METHODS: We conducted a retrospective study of 134 IBD patients who received thiopurine treatment. The 6-methylmercaptopurine (6-MMP)/6-TGN values after taking the same dose of thiopurine preparations for at least 28 days were included. RESULTS: There was a significant decrease in the 6-MMP/6-TGN ratio in time-dependent 5-ASA compared with group without 5-ASA preparations and the pH-dependent 5-ASA group (p = 0.008 and < 0.001 respectively). Spearman's rank correlation coefficient indicated a negative relationship between the daily oral dose of time-dependent 5-ASA and the 6-MMP/6-TGN ratio (r = -0.362, p = 0.003). Multivariate logistic regression analysis was performed in the groups with 6-MMP/6-TGN ratios of 1 or more and less than 1. The use of time-dependent 5-ASA and concomitant allopurinol negatively affected the independent 6-MMP/6-TGN ratio (p = 0.006 and 0.007 respectively). CONCLUSION: Our study revealed that time-dependent but not pH-dependent 5-ASA decreases the 6-MMP/6-TGN ratio. We also confirmed that concomitant allopurinol results in a low 6-MMP/6TGN ratio.

CpG DNA facilitate the inactivated transmissible gastroenteritis virus in enhancing the local and systemic immune response of pigs via oral administration.

Transmissible gastroenteritis virus (TGEV) replicates in the small intestine and induces enteritis and watery diarrhea. Establishment of local immunity in the intestine would thus prevent TGEV transmission. CpG DNA has been reported as a promising mucosal adjuvant in some animals. The effects of oral immunization of CpG DNA together with inactivated TGEV (ITGEV) were investigated in this study. Pigs (6 weeks old) were orally immunized with ITGEV plus CpG DNA. The TGEV-specific IgA level in the intestinal tract and the TGEV-specific IgG level in serum significantly increased following immunization with ITGEV plus CpG DNA (P ≤ 0.05). Moreover, populations of IgA-secreting cells, CD3+ T lymphocytes and intraepithelial lymphocytes (IELs), in the intestine increased significantly after immunization with ITGEV plus CpG DNA (P ≤ 0.05). Furthermore, the expression of IL-6, IL-12 and interferon-γ (IFN-γ) in ligated intestine segments increased significantly after injection with ITGEV plus CpG DNA (P ≤ 0.05). Taken together, these data suggest that oral immunization of ITGEV plus CpG DNA elicits a local immune response. Further studies are required to determine whether this immunity provides protection against TGEV in pigs.

Interindividual variability in TPMT enzyme activity: 10 years of experience with thiopurine pharmacogenetics and therapeutic drug monitoring.

BACKGROUND & AIMS: TPMT activity and metabolite determination (6-thioguanine nucleotides [6-TGN] and 6-methylmercaptopurine nucleotides [6-MMPN]) remain controversial during thiopurine management. This study assessed associations between patient characteristics and TPMT activity, and their impact on metabolite levels. PATIENTS & METHODS: A retrospective review of the laboratory database from a French university hospital identified 7360 patients referred for TPMT phenotype/genotype determination, and/or for 6-TGN/6-MMPN monitoring. RESULTS: Four TPMT phenotypes were identified according to TPMT activity distribution: low, intermediate, normal/high and very high. Based on 6775 assays, 6-TGN concentrations were 1.6-fold higher in TPMT-deficient patients compared with TPMT-normal patients. Azathioprine dose and TPMT genotype were significant predictors of metabolite levels. Furthermore, 6-MMPN and 6-MMPN: 6-TGN ratios were, respectively, 1.6- and 2.2-fold higher in females than in males, despite similar TPMT, 6-TGN and azathioprine doses. An unfavorable ratio (≥20) was associated with a slightly higher TPMT activity. CONCLUSION: These results illustrate the usefulness of pharmacogenomics and metabolite measurement to improve the identification of noncompliance and patients at high risk for toxicity or therapeutic resistance. Original submitted 13 November 2013; Revision submitted 30 January 2014.

Medication adherence and quality of life in pediatric inflammatory bowel disease.

OBJECTIVE: To examine the relationship between medication adherence and quality of life (QOL) in adolescent patients with inflammatory bowel disease (IBD) utilizing a multimethod adherence assessment approach. METHODS: Medication adherence in 36 adolescents with IBD was assessed via interviews, pill counts, and biological assays. QOL was assessed via patient and parent report. Pediatric gastroenterologists provided disease severity assessments. RESULTS: Hierarchical multiple regression analyses revealed that adherence contributed significant variance to patient-reported QOL but not parent-reported QOL. Nonadherence to 6-MP/azathioprine was related to poorer patient-reported physical health QOL. Greater self-reported 5-ASA adherence was related to poorer overall psychological health QOL, and particularly social functioning QOL. CONCLUSIONS: Results provide preliminary support for the negative effects of 6-MP/azathioprine nonadherence on QOL and an inverse relationship between 5-ASA adherence and QOL in this population. Adherence burden in patients and the utility of multimethod adherence assessment in research are discussed.

Studies on umami taste. Synthesis of new guanosine 5'-phosphate derivatives and their synergistic effect with monosodium glutamate.

A number of N2-alkyl and N2-acyl derivatives of guanosine 5'-phosphate (GMP) have been synthesized and tested for their synergistic effect with monosodium L-glutamate (MSG), the prototypical substance imparting umami taste to savory-based foods. Capacities to enhance the taste intensity of MSG (gamma values) were estimated through subjective comparisons of MSG/nucleotide mixtures in water with appropriate solutions of MSG alone. Assuming beta = gamma[nucleotide]/gamma[IMP], beta values of the N2-substituted GMPs were found in the range 1.2-5.7. Such values appear to be related to the chain length of the substituent in the 2-position of the purine nucleus and dependent on the replacement of a CH 2 group with an S atom and/or with an alpha-CO group. These findings indicate that the exocyclic NHR group of the guanine moiety is actively implicated in the synergism between GMP derivatives and MSG. Theoretical calculations suggest that an anti conformation is probably assumed by ribonucleotide molecules interacting with umami receptors.

Potentiation of the chemotherapeutic effect of 5-fluorouracil by combination with guanosine 5'-monophosphate.

The chemotherapeutic effect of the 5-fluorouracil (5-FU)-guanosine 5'-monophosphate (GMP) combination in various mouse tumor systems was compared with that of 5-FU monotherapy. Antitumor activity of 5-FU against L-1210 leukemia was potentiated without increasing its toxicity to the host when GMP at 30-100 mg/kg/day was injected simultaneously with 5-FU. Any time interval between the administrations of 5-FU and GMP diminished the increase in survival. Moreover, the combination of 5-FU and GMP at 100 mg/kg/day produced marked antitumor effects in the P-388 leukemia, ascites sarcoma 180, and Ehrlich ascites carcinoma systems. GMP also potentiated the antitumor activity of 5-FU in solid tumor systems (adenocarcinoma 755 and Lewis lung carcinoma) when given by intravenous injection, but not intraperitoneal injection. The therapeutic effect of 5-FU on various murine tumors was markedly potentiated by GMP at 100 mg/kg/day or less without increasing the toxicity to the host.

Biochemical approaches to the combination chemotherapy of colon cancer.

The employment of biochemical concepts to select drugs for use in the treatment of colorectal cancer is advocated. It is stressed that new drug mixtures, even those employing agents inactive alone, with unique mechanisms of action may be fashioned through biochemical design. Following delineation of activity in animal model systems, these drug combinations then become candidates for use in man. It is emphasized that 6-thioguanine is a particularly attractive agent for consideration as a component of new combinations of drugs to be used in patients with cancer. The desirability of this agent derives from (a) the known, albeit weak, activity of 6-thioguanine against colorectal neoplasms of man, thereby providing some inherent activity to be joined by additional materials; (b) a knowledge of several major biochemical and pharmacologic determinants of tissue susceptibility to its cytotoxic action, possibly allowing the ultimate selection of patients with a high probability of response; and (c) the availability of four different agents or classes of agents which synergistically interact with 6-thioguanine to inhibit the growth of malignant cells by diverse biochemical mechanisms.