One amino acid difference is critical for suppression of the development of experimental autoimmune diabetes (EAD) with intravenous injection of insulinB:9-23 peptide

InsulinB:9-23 peptide (insB:9-23) reactive T cells has been reported as crucial for type 1 diabetes. In this study, experimental autoimmune diabetes (EAD) mice, which subcutaneous immunization of ins1 or 2B:9-23 induced autoimmune diabetes in F1(B7.1B6 × BALB/c), was investigated for antigen specific therapy to delete pathogenic T cells. Intravenous injection of ins1 or 2B:9-23 significantly delayed the development of diabetes on the corresponding peptide-induced EAD (ins1EAD or ins2EAD) concomitant with reduced insulitis and insulin autoantibodies expression. Population of Foxp3⁺ CD4⁺ T cell was unchanged whereas the level of anti-insB:9-23 specific IgG_2a but not IgG₁ were specifically decreased, suggesting reduction of pathogenic insB:9-23 reactive T cells. Most interestingly, intravenous administration of ins2B:9-23, whose amino acid sequence had one amino acid difference at position 9 delayed the development of diabetes in both ins1EAD and ins2EAD whereas ins1B:9-23 administration delayed diabetes in the ins1EAD but not ins2EAD, suggesting that one amino acid difference gives critical influence on the effect of intravenous injection of antigenic peptide for type 1 diabetes.     

Design and synthesis of novel prodrugs of 2'-deoxy-2'-methylidenecytidine activated by membrane dipeptidase overexpressed in tumor tissues

DNA microarray analysis comparing human tumor tissues with normal tissues including hematopoietic progenitor cells resulted in identification of membrane dipeptidase as a prodrug activation enzyme. Novel prodrugs of 2'-deoxy-2'-methylidenecytidine (DMDC) including compound 23 that are activated by membrane dipeptidase (MDP) preferentially in tumor tissue were designed and synthesized to generate the active drug, DMDC, after hydrolysis of the dipeptide bond followed by spontaneous cyclization of the promoiety.     

Crystal structures of N-acetylglucosamine-phosphate mutase, a member of the alpha-D-phosphohexomutase superfamily, and its substrate and product complexes

N-acetylglucosamine-phosphate mutase (AGM1) is an essential enzyme in the synthetic process of UDP-N-acetylglucosamine (UDP-GlcNAc). UDP-GlcNAc is a UDP sugar that serves as a biosynthetic precursor of glycoproteins, mucopolysaccharides, and the cell wall of bacteria. Thus, a specific inhibitor of AGM1 from pathogenetic fungi could be a new candidate for an antifungal reagent that inhibits cell wall synthesis. AGM1 catalyzes the conversion of N-acetylglucosamine 6-phosphate (GlcNAc-6-P) into N-acetylglucosamine 1-phosphate (GlcNAc-1-P). This enzyme is a member of the alpha-D-phosphohexomutase superfamily, which catalyzes the intramolecular phosphoryl transfer of sugar substrates. Here we report the crystal structures of AGM1 from Candida albicans for the first time, both in the apoform and in the complex forms with the substrate and the product, and discuss its catalytic mechanism. The structure of AGM1 consists of four domains, of which three domains have essentially the same fold. The overall structure is similar to those of phosphohexomutases; however, there are two additional beta-strands in domain 4, and a circular permutation occurs in domain 1. The catalytic cleft is formed by four loops from each domain. The N-acetyl group of the substrate is recognized by Val-370 and Asn-389 in domain 3, from which the substrate specificity arises. By comparing the substrate and product complexes, it is suggested that the substrate rotates about 180 degrees on the axis linking C-4 and the midpoint of the C-5-O-5 bond in the reaction.     

Decreased serum dependence in the growth of NIH3T3 cells from the overexpression of human nuclear receptor-binding SET-domain-containing protein 1 (NSD1) or fission yeast su(var)3-9, enhancer-of-zeste, trithorax 2 (SET2)

Nuclear receptor-binding SET-domain-containing protein 1 (NSD1), a culprit gene for Sotos syndrome, contains a su(var)3-9, enhancer-of-zeste, trithorax (SET) domain that is responsible for histone methyltransferase activity and other domains such as plant homeodomain (PHD) and proline-tryptophan-tryptophan-proline (PWWP) involved in protein-protein interactions in the C-terminal half of NSD1. To elucidate the function of NSD1 on cell growth, we overexpressed NSD1 in NIH3T3 cells. Cells overexpressing NSD1 grew in the presence of 2% serum, whereas vector transfected cells did not. Overexpression of the C-terminal half of NSD1 but not the N-terminal half of NSD1 also produced cell growth under low serum concentration. Furthermore, overexpression in NIH3T3 of Schizosaccharomyces pombe SET2 which has a SET domain but not PHD or PWWP domains conferred the reduced serum dependence. Thus, the SET domain of NSD1 is involved in cell growth by modulating serum dependence.     

Perioperative Challenges and Surgical Treatment of Large Simple,and Infectious Liver Cyst - A 12-Year Experience

Background

Cystic lesions of the liver consist of a heterogeneous group of disorders that can present diagnostic and therapeutic challenges.

Methods

A retrospective review of all medical records of adult patients diagnosed with large (>7 cm) cystic lesions of the liver between January 2000 and December 2011, at Kurume University Hospital. Cases with polycystic disease were excluded.

Results

Twenty three patients were identified. The mean size was 13.9 cm (range, 7-22cm). The majority of simple cysts were found in women (females: males, 2: 21). In 19 patients, the cyst was removed surgically by wide deroofing (laparoscopically in 16 cases, combined with ethanol sclerotherapy in 13 cases). Infection of the liver cyst occurred in one patient, who later underwent central bi-segmentectomy.

Conclusion

Simple large cysts of the liver can be successfully treated by laparoscopic deroofing and alcohol sclerotherapy. Large hepatic cyst considered to need drainage should be removed surgically to avoid possible infection.     

Design and synthesis of novel allosteric MEK inhibitor CH4987655 as an orally available anticancer agent

The MAP kinase pathway is one of the most important pathways involved in cell proliferation and differentiation, and its components are promising targets for antitumor drugs. Design and synthesis of a novel MEK inhibitor, based on the 3D-structural information of the target enzyme, and then multidimensional optimization including metabolic stability, physicochemical properties and safety profiles were effectively performed and led to the identification of a clinical candidate for an orally available potent MEK inhibitor, CH4987655, possessing a unique 3-oxo-oxazinane ring structure at the 5-position of the benzamide core structure. CH4987655 exhibits slow dissociation from the MEK enzyme, remarkable in vivo antitumor efficacy both in mono- and combination therapy, desirable metabolic stability, and insignificant MEK inhibition in mouse brain, implying few CNS-related side effects in human. An excellent PK profile and clear target inhibition in PBMC were demonstrated in a healthy volunteer clinical study.     

Isolation and functional analysis of a gene,tcsB, encoding a transmembrane hybrid-type histidine kinase from Aspergillus nidulans

We cloned and characterized a novel Aspergillus nidulans histidine kinase gene, tcsB, encoding a membrane-type two-component signaling protein homologous to the yeast osmosensor synthetic lethal N-end rule protein 1 (SLN1), which transmits signals through the high-osmolarity glycerol response 1 (HOG1) mitogen-activated protein kinase (MAPK) cascade in yeast cells in response to environmental osmotic stimuli. From an A. nidulans cDNA library, we isolated a positive clone containing a 3,210-bp open reading frame that encoded a putative protein consisting of 1,070 amino acids. The predicted tcsB protein (TcsB) has two probable transmembrane regions in its N-terminal half and has a high degree of structural similarity to yeast Sln1p, a transmembrane hybrid-type histidine kinase. Overexpression of the tcsB cDNA suppressed the lethality of a temperature-sensitive osmosensing-defective sln1-ts yeast mutant. However, tcsB cDNAs in which the conserved phosphorylation site His(552) residue or the phosphorelay site Asp(989) residue had been replaced failed to complement the sln1-ts mutant. In addition, introduction of the tcsB cDNA into an sln1delta sho1delta yeast double mutant, which lacked two osmosensors, suppressed lethality in high-salinity media and activated the HOG1 MAPK. These results imply that TcsB functions as an osmosensor histidine kinase. We constructed an A. nidulans strain lacking the tcsB gene (tcsBdelta) and examined its phenotype. However, unexpectedly, the tcsBdelta strain did not exhibit a detectable phenotype for either hyphal development or morphology on standard or stress media. Our results suggest that A. nidulans has more complex and robust osmoregulatory systems than the yeast SLN1-HOG1 MAPK cascade.     

Effects of iprodione and fludioxonil on glycerol synthesis and hyphal development in Candida albicans

We investigated the effects of iprodione and fludioxonil on the pathogenic yeast Candida albicans. Growth of the wild-type IFO1385 strain of C. albicans was inhibited by both fungicides, while Saccharomyces cerevisiae was basically unaffected by them even at a concentration of 25 microg/ml. Both fungicides stimulated glycerol synthesis in C. albicans but not in S. cerevisiae. The antioxidant alpha-tocopherol acetate and the cytochrome P-450 inhibitor piperonyl butoxide antagonized the fungitoxicity of iprodione and fludioxonil in C. albicans. It is known that mutations within the histidine kinase NIK1/OS-1 gene confer resistance to iprodione and fludioxonil in Neurospora crassa, while the fungicide-insensitive S. cerevisiae has only one histidine kinase SLN1 gene in its genome. In contrast, C. albicans has three histidine kinase genes, namely CaSLN1, CaNIK1/COS1, and CaHK1, the null mutants of which were found to impair the hyphal formation. Iprodione and fludioxonil were found to suppress filamentation when the IFO1385 strain was incubated on a solid medium containing fetal bovine serum. These observations suggest that iprodione and fludioxonil interfere with the CaNIK1/COS1 signal transduction pathway, resulting in glycerol synthesis stimulation and the inhibition of hyphal formation.     

Initiation of cleavage in starfish eggs by the injection of triton-treated spermatozoa

Triton X-100-treated spermatozoa were injected into immature (fully grown, germinal vesicle stage) or mature (pronuclear stage) oocytes of the starfish, Asterina pectinifera, to study relation between initiation of cleavage and cortical reaction. Immature oocytes into which Triton X-100-treated spermatozoa were injected were treated with 1-methyladenine. Such immature oocytes initiated cleavage after completion of meiosis without formation of the fertilization membrane. The same results were obtained when Triton X-100-treated spermatozoa were injected into mature oocytes. Control oocytes into which only calcium-free sea water was injected did not cleave. These results indicate that the initiation of cleavage is independent of the cortical reaction but dependent on the existence of spermatozoa (spermatozoon) in the egg cytoplasm.