Time-resolved FTIR study on the structural switching of human galectin-1 by light-induced disulfide bond formation.

Disulfide bonds play a fundamental role in controlling the tertiary structure of proteins; the formation or cleavage of some disulfide bonds can switch the structures and/or functions of proteins. Human galectin-1 (hGal-1), which is a lectin protein, exemplifies how both structure and function are changed by disulfide bonds; the structure and sugar-binding ability of hGal-1 are altered by the formation and cleavage of its three intra-molecular disulfide bonds. In the present study, the dynamics of the structural change of hGal-1 by the formation of disulfide bonds were investigated by time-resolved FTIR spectroscopy combined with a modification in which its thiol groups (-SH) were replaced with S-nitrosylated groups (SNO). Photodissociation of NO from SNO in reduced hGal-1 induced disulfide bond formation and transformed it into the oxidised form. The structural change to the oxidised form involved three distinct kinetics with fast (<300 s), middle (∼600 s), and slow (∼6400 s) lifetimes. In an examination of hGal-1 in the lactose-bound form, structural changes owing to the release of substrate lactose were also observed upon disulfide bond formation. The present method using the photodissociation of NO is useful for monitoring the dynamics of structural changes following disulfide formation.

An ionic liquid composed of purely functional sensing molecules: a colorimetrically calcium responsive ionic liquid.

A highly lipophilic ionic liquid (IL) consisting of stoichiometrically equal amounts of two purely functional chemical sensing molecules, an anionic calcium ionophore and a cationic dye, was synthesized for the first time, and used as a component for a poly(vinyl chloride)-based or neat liquid membrane optical sensor. This is the first report of an IL consisting of purely functional chemical sensing molecules, which is completely different from the previously reported ionic liquids typically consisting of imidazolium or other lipophilic cations. Since the present IL contained an extremely high concentration of dyes, the IL-based sensor showed dramatically enhanced sensitivity (13 times higher compared to that of a conventional sensor), and fully reversible and selective response to Ca2+. Preliminary investigation on the unique response characteristics of the present liquid membrane IL-based sensor was performed with the responses to Ca2+ and Na+.

Use of a chemically induced-colon carcinogenesis-prone Apc-mutant rat in a chemotherapeutic bioassay.

BACKGROUND: Chemotherapeutic bioassay for colorectal cancer (CRC) with a rat model bearing chemically-induced CRCs plays an important role in the development of new anti-tumor drugs and regimens. Although several protocols to induce CRCs have been developed, the incidence and number of CRCs are not much enough for the efficient bioassay. Recently, we established the very efficient system to induce CRCs with a chemically induced-colon carcinogenesis-prone Apc-mutant rat, Kyoto Apc Delta (KAD) rat. Here, we applied the KAD rat to the chemotherapeutic bioassay for CRC and showed the utility of the KAD rat. METHODS: The KAD rat has been developed by the ENU mutagenesis and carries a homozygous nonsense mutation in the Apc gene (S2523X). Male KAD rats were given a single subcutaneous injection of AOM (20 mg/kg body weight) at 5 weeks of age. Starting at 1 week after the AOM injection, they were given 2% DSS in drinking water for 7 days. Tumor-bearing KAD rats were divided into experimental and control groups on the basis of the number of tumors observed by endoscopy at week 8. The 5-fluorouracil (5-FU) was administrated intravenously a dose of 50 or 75 mg/kg weekly at week 9, 10, and 11. After one-week interval, the 5-FU was given again at week 13, 14, and 15. At week 16, animals were sacrificed and tumor number and volume were measured macroscopically and microscopically. RESULTS: In total 48 tumors were observed in 27 KAD rats with a 100% incidence at week 8. The maximum tolerated dose for the KAD rat was 50 mg/kg of 5-FU. Macroscopically, the number or volume of tumors in the 5-FU treated rats was not significantly different from the control. Microscopically, the number of adenocarcinoma in the 5-FU treated rats was not significantly different (p < 0.02) from that of the control. However, the volume of adenocarcinomas was significantly lower than in the control. Anticancer effect of the 5-FU could be obtained only after the 16 weeks of experimental period. CONCLUSION: The use of the AOM/DSS-treated tumor-bearing KAD rats could shorten the experimental period and reduce the number of animals examined in the chemotherapeutic bioassay. The efficient bioassay with the AOM/DSS-treated tumor-bearing KAD rats would promote the development of new anti-tumor drugs and regimens.

IL-22 attenuates IL-25 production by lung epithelial cells and inhibits antigen-induced eosinophilic airway inflammation.

BACKGROUND: IL-22 functions as both a proinflammatory cytokine and an anti-inflammatory cytokine in various inflammations, depending on the cellular and cytokine milieu. However, the roles of IL-22 in the regulation of allergic airway inflammation are still largely unknown. OBJECTIVE: We sought to determine whether IL-22 is involved in the regulation of allergic airway inflammation. METHODS: We examined IL-22 production and its cellular source at the site of antigen-induced airway inflammation in mice. We also examined the effect of IL-22 neutralization, as well as IL-22 administration, on antigen-induced airway inflammation. We finally examined the effect of IL-22 on IL-25 production from a lung epithelial cell line (MLE-15 cells). RESULTS: Antigen inhalation induced IL-22 production in the airways of sensitized mice. CD4(+) T cells, but not other lymphocytes or innate cells, infiltrating in the airways produced IL-22, and one third of IL-22-producing CD4(+) T cells also produced IL-17A. The neutralization of IL-22 by anti-IL-22 antibody enhanced antigen-induced IL-13 production, eosinophil recruitment, and goblet cell hyperplasia in the airways. On the other hand, intranasal administration of recombinant IL-22 attenuated antigen-induced eosinophil recruitment into the airways. Moreover, anti-IL-22 antibody enhanced antigen-induced IL-25 production in the airways, and anti-IL-25 antibody reversed the enhancing effect of anti-IL-22 antibody on antigen-induced eosinophil recruitment into the airways. Finally, IL-22 inhibited IL-13-mediated enhancement of IL-25 expression in IL-1ß- or LPS-stimulated MLE-15 cells. CONCLUSION: IL-22 attenuates antigen-induced airway inflammation, possibly by inhibiting IL-25 production by lung epithelial cells.

Capture of influenza viruses and prevention of their infection by coral mineral powder (sango mineral powder).

The anti-influenza virus activity of fossilized marine coral powder (sango mineral powder, SMP) was studied. SMP is composed in terms of mass of around 25 % of calcium and 10 % of magnesium, respectively, principally as dolomite (CaMg(CO(3))(2)) but not as calcium oxide (CaO) or magnesium oxide (MgO). By mixing the influenza virus with SMP, the infectivity of the virus substantially decreased and there was more than a 10(4) reduction on the 3rd d of infection. The antiviral effect was observed against all the type A and B strains of the influenza virus examined including the H1N1 2009 pandemic and H5N1 avian viruses. The surface structure of SMP was highly porous and the anti-influenza activity was explained by the adsorption of the viral particles onto its surface. The binding of viruses to SMP was strong and stable in the physiological condition, and the attached viruses detached only in the presence of a high concentration of phosphate. This was similar to the binding of protein to hydroxyapatite, suggesting an ionic interaction between SMP and the viral proteins. SMP maintained its activity to capture influenza viruses even after being immobilized on a non-woven textile. SMP would be useful as a practical anti-influenza tool especially in preparation for the next pandemic virus.

Involvement of DNA Damage Response via the Ccndbp1-Atm-Chk2 Pathway in Mice with Dextran-Sodium-Sulfate-Induced Colitis.

The dextran sodium sulfate (DSS)-induced colitis mouse model has been widely utilized for human colitis research. While its mechanism involves a response to double-strand deoxyribonucleic acid (DNA) damage, ataxia telangiectasia mutated (Atm)-checkpoint kinase 2 (Chk2) pathway activation related to such response remains unreported. Recently, we reported that cyclin D1-binding protein 1 (Ccndbp1) activates the pathway reflecting DNA damage in its knockout mice. Thus, this study aimed to examine the contribution of Ccndbp1 and the Atm-Chk2 pathway in DSS-induced colitis. We assessed the effect of DSS-induced colitis on colon length, disease activity index, and histological score and on the Atm-Chk2 pathway and the subsequent apoptosis in Ccndbp1-knockout mice. DSS-induced colitis showed distal colon-dominant Atm and Chk2 phosphorylation, increase in TdT-mediated dUTP-biotin nick end labeling and cleaved caspase 3-positive cells, and histological score increase, causing disease activity index elevation and colon length shortening. These changes were significantly ameliorated in Ccndbp1-knockout mice. In conclusion, Ccndbp1 contributed to Atm-Chk2 pathway activation in the DSS-induced colitis mouse model, causing inflammation and apoptosis of mucosal cells in the colon.

Cyclin D1 Binding Protein 1 Responds to DNA Damage through the ATM-CHK2 Pathway.

Cyclin D1 binding protein 1 (CCNDBP1) is considered a tumor suppressor, and when expressed in tumor cells, CCNDBP1 can contribute to the viability of cancer cells by rescuing these cells from chemotherapy-induced DNA damage. Therefore, this study focused on investigating the function of CCNDBP1, which is directly related to the survival of cancer cells by escaping DNA damage and chemoresistance. Hepatocellular carcinoma (HCC) cells and tissues obtained from Ccndbp1 knockout mice were used for the in vitro and in vivo examination of the molecular mechanisms of CCNDBP1 associated with the recovery of cells from DNA damage. Subsequently, gene and protein expression changes associated with the upregulation, downregulation, and irradiation of CCNDBP1 were assessed. The overexpression of CCNDBP1 in HCC cells stimulated cell growth and showed resistance to X-ray-induced DNA damage. Gene expression analysis of CCNDBP1-overexpressed cells and Ccndbp1 knockout mice revealed that Ccndbp1 activated the Atm-Chk2 pathway through the inhibition of Ezh2 expression, accounting for resistance to DNA damage. Our study demonstrated that by inhibiting EZH2, CCNDBP1 contributed to the activation of the ATM-CHK2 pathway to alleviate DNA damage, leading to chemoresistance.

Intestinal duplication diagnosed preoperatively with double-balloon enteroscopy: an extremely rare case report and literature review.

Gastrointestinal duplications are congenital malformations that are usually observed in pediatric patients. Diagnosis in adulthood is quite rare, and preoperative diagnosis of gastrointestinal duplication is difficult, particularly in the small intestine. We encountered an extremely rare adult case of duplication of the jejunum, which showed a stomach-like form diagnosed using double-balloon enteroscopy (DBE). The patient was an 18-year-old male who had been experiencing upper abdominal pain and vomiting repeatedly without any triggers for 3 years. Various examinations were performed, but no cause of symptoms was found. DBE revealed a narrow opening of the lumen at the upper jejunum, and the lumen was covered with mucosal folds similar to those of the stomach. Enteroclysis via DBE showed a tubular structure on the mesenteric side of the jejunum. We diagnosed a jejunal tubular duplication with ectopic gastric mucosa and underwent partial small bowel resection. The patient's abdominal symptoms resolved. From this, DBE can be a useful tool for diagnosing intestinal duplication in adults. We believe that this case and literature review will facilitate the accurate and prompt diagnosis of small intestinal duplication.

Phytochrome-interacting factor 4 and 5 (PIF4 and PIF5) activate the homeobox ATHB2 and auxin-inducible IAA29 genes in the coincidence mechanism underlying photoperiodic control of plant growth of Arabidopsis thaliana.

The plant circadian clock generates rhythms with a period close to 24 h, and it controls a wide variety of physiological and developmental events. Among clock-controlled developmental events, the best characterized is the photoperiodic control of flowering time, which is mediated through the CONSTANS (CO)-FLOWERING LOCUS T (FT) pathway in Arabidopsis thaliana. The clock also regulates the diurnal plant growth including the elongation of hypocotyls in a short day (SDs)-specific manner. In this mechanism, phytochromes (mainly phyB) and the PHYTOCHROME-INTERACTING FACTOR4 (PIF4) and PIF5, encoding phytochrome-interacting basic helix-loop-helix (bHLH) transcription factors, play crucial roles. The time of day-specific and photoperiodic control of hypocotyl elongation is best explained by the accumulation of the PIF4 and PIF5 proteins during night-time before dawn, especially under SDs, due to coincidence between the internal (circadian rhythm) and external (photoperiod) time cues. However, the PIF4- and/or PIF5-controlled downstream factors have not yet been identified. Here, we provide evidence that ARABIDOPSIS THALIANA HOMEOBOX PROTEIN2 (ATHB2), together with auxin-inducible IAA29, is diurnally expressed with a peak at dawn under the control of PIF4 and PIF5 specifically in SDs. This coincidentally expressed transcription factor serves as a positive regulator for the elongation of hypocotyls. The expression profiles of ATHB2 were markedly altered in certain clock and phytochrome mutants, all of which show anomalous phenotypes with regard to the photoperiodic control of hypocotyl elongation. Taken together, we propose that an external coincidence model involving the clock-controlled PIF4/PIF5-ATHB2 pathway is crucial for the diurnal and photoperiodic control of plant growth in A. thaliana.

Modulation of serotonin in the gut-liver neural axis ameliorates the fatty and fibrotic changes in non-alcoholic fatty liver.

The etiology of non-alcoholic fatty liver disease (NAFLD) consists of various factors, including neural signal pathways. However, the molecular mechanisms of the autonomic neural signals influencing NAFLD progression have not been elucidated. Therefore, we examined the involvement of the gut-liver neural axis in NAFLD development and tested the therapeutic effect of modulation of this axis in this study. To test the contribution of the gut-liver neural axis, we examined NAFLD progression with respect to body weight, hepatic steatosis, fibrosis, intestinal tight junction, microbiota and short-chain fatty acids in NAFLD models of choline-deficient defined L-amino-acid and high-fat diet-fed mice with or without blockades of autonomic nerves from the liver. Blockade of the neural signal from the liver to the gut in these NAFLD mice models ameliorated the progression of liver weight, hepatic steatosis and fibrosis by modulating serotonin expression in the small intestine. It was related to the severity of the liver pathology, the tight junction protein expression, microbiota diversity and short-chain fatty acids. These effects were reproduced by administrating serotonin antagonist, which ameliorated the NAFLD progression in the NAFLD mice models. Our study demonstrated that the gut-liver neural axis is involved in the etiologies of NAFLD progression and that serotonin expression through this signaling network is the key factor of this axis. Therefore, modulation of the gut-liver neural axis and serotonin antagonist ameliorates fatty and fibrotic changes in non-alcoholic fatty liver, and can be a potential therapeutic target of NAFLD.This article has an associated First Person interview with the first author of the paper.