Ayatoshi Andou

Dietary Histidine Ameliorates Murine Colitis by Inhibition of Proinflammatory Cytokine Production From Macrophages

BACKGROUND & AIMS Elemental diet (ED) is effective for human Crohns disease (CD). Although some of this effectiveness may be due to its low antigenic load and low fat content, the mechanisms remain unclear. We sought to assess the role of histidine, one of the constituent amino acids of ED, in controlling colitis. METHODS The interleukin (IL)-10-deficient (IL-10(-/-)) cell transfer model of colitis was used. SCID mice with colitis induced by transfer of IL-10(-/-) cells were maintained on experimented diets containing either single amino acids or a mixture. The severity of colitis was assessed by wet colon weight. Colonic tumor necrosis factor (TNF)-alpha messenger RNA (mRNA) expression was detected by quantitative reverse-transcription polymerase chain reaction. Mouse peritoneal macrophages were stimulated by lipopolysaccharides (LPS), with or without amino acids. The concentration of cytokines in the supernatant was determined by enzyme-linked immunosorbent assay. Inhibitor of nuclear factor (NF)-kappaB-alpha and nuclear p65 were confirmed by immunoblotting. RESULTS In the IL-10(-/-) transfer model, dietary histidine, but not alanine, reduced histologic damage and colon weight and TNF-alpha mRNA expression. Histidine inhibited LPS-induced TNF-alpha and IL-6 production by mouse macrophages in a concentration-dependent manner, whereas alanine or histidine-related metabolites had no such effect. Histidine inhibited LPS-induced NF-kappaB in macrophages. CONCLUSIONS These results showed that histidine could be a novel therapeutic agent for CD by inhibition of NF-kappaB activation, following down-regulation of proinflammatory cytokine production by macrophages. Thus, our studies provided new insights into the roles of amino acid metabolism in the pathophysiology of CD and for therapeutic strategies.

Novel, Objective, Multivariate Biomarkers Composed of Plasma Amino Acid Profiles for the Diagnosis and Assessment of Inflammatory Bowel Disease

Background Inflammatory bowel disease (IBD) is a chronic intestinal disorder that is associated with a limited number of clinical biomarkers. In order to facilitate the diagnosis of IBD and assess its disease activity, we investigated the potential of novel multivariate indexes using statistical modeling of plasma amino acid concentrations (aminogram). Methodology and Principal Findings We measured fasting plasma aminograms in 387 IBD patients (Crohns disease (CD), n = 165; ulcerative colitis (UC), n = 222) and 210 healthy controls. Based on Fisher linear classifiers, multivariate indexes were developed from the aminogram in discovery samples (CD, n = 102; UC, n = 102; age and sex-matched healthy controls, n = 102) and internally validated. The indexes were used to discriminate between CD or UC patients and healthy controls, as well as between patients with active disease and those in remission. We assessed index performances using the area under the curve of the receiver operating characteristic (ROC AUC). We observed significant alterations to the plasma aminogram, including histidine and tryptophan. The multivariate indexes established from plasma aminograms were able to distinguish CD or UC patients from healthy controls with ROC AUCs of 0.940 (95% confidence interval (CI): 0.898–0.983) and 0.894 (95%CI: 0.853–0.935), respectively in validation samples (CD, n = 63; UC, n = 120; healthy controls, n = 108). In addition, other indexes appeared to be a measure of disease activity. These indexes distinguished active CD or UC patients from each remission patients with ROC AUCs of 0.894 (95%CI: 0.853–0.935) and 0.849 (95%CI: 0.770–0.928), and correlated with clinical disease activity indexes for CD (rs = 0.592, 95%CI: 0.385–0.742, p<0.001) or UC (rs = 0.598, 95%CI: 0.452–0.713, p<0.001), respectively. Conclusions and Significance In this study, we demonstrated that established multivariate indexes composed of plasma amino acid profiles can serve as novel, non-invasive, objective biomarkers for the diagnosis and monitoring of IBD, providing us with new insights into the pathophysiology of the disease.

Structure-activity relationship study, target identification, and pharmacological characterization of a small molecular IL-12/23 inhibitor, APY0201.

Interleukin-12 (IL-12) and IL-23 are proinflammatory cytokines and therapeutic targets for inflammatory and autoimmune diseases, including inflammatory bowel diseases, psoriasis, rheumatoid arthritis, and multiple sclerosis. We describe the discovery of APY0201, a unique small molecular IL-12/23 production inhibitor, from activated macrophages and monocytes, and demonstrate ameliorated inflammation in an experimental model of colitis. Through a chemical proteomics approach using a highly sensitive direct nanoflow LC-MS/MS system and bait compounds equipped with the FLAG epitope associated regulator of PIKfyve (ArPIKfyve) was detected. Further study identified its associated protein phosphoinositide kinase, FYVE finger-containing (PIKfyve), as the target protein of APY0201, which was characterized as a potent, highly selective, ATP-competitive PIKfyve inhibitor that interrupts the conversion of phosphatidylinositol 3-phosphate (PtdIns3P) to PtdIns(3,5)P2. These results elucidate the function of PIKfyve kinase in the IL-12/23 production pathway and in IL-12/23-driven inflammatory disease pathologies to provide a compelling rationale for targeting PIKfyve kinase in inflammatory and autoimmune diseases.

Regulatory Roles of Amino Acids in Immune Response

Amino acids are not only the building blocks of proteins but are also key regulators of various pathological and physiological processes, including immune responses, in living cells. However, the mechanisms responsible for these effects of amino acids are largely unknown. The regulatory roles of amino acids in the immune system can be considered from two perspectives, namely, the enhancement of the immune response that protects individuals from infections and malignant neoplasms, and the reduction of over-responses such as inflammation and autoimmunity. In this review, we focus on the regulatory roles of amino acids in the immune response, showing how several amino acids (e.g., glutamine, arginine, tryptophan, cystine/cysteine, glutamate, and branched-chain amino acids) enhance immunity. Additionally, we describe how one amino acid, histidine, functions as an anti-inflammatory agent in colitis.

Tu1864 A Novel Orally Active Phosphatidylinositol 3-Phosphate 5-Kinase (Pikfyve) Inhibitor Ameliorates Mouse Colitis by Inhibition of IL-12 and IL-23 Production From Macrophages

A Novel Orally Active Phosphatidylinositol 3-Phosphate 5-Kinase (Pikfyve) Inhibitor Ameliorates Mouse Colitis by Inhibition of IL-12 and IL-23 Production From Macrophages Ayatoshi Andou, Takashi Yamamoto, Eviryanti Agung, Yukie Seki, Hikaru Nishio, Manami Shuto, Misato Noguchi, Yoichiro Shima, Sen Takeshita, Ryohei Yokoyama, Nobuhiko Hayakawa, Masatsugu Noguchi, Shunsuke Kageyama, Hiroyuki Eda, Makoto Shiozaki, Itsuya Tanabe, Ryusuke Nakagawa, Kuniya Sakurai, Shoji Masataka