Design and synthesis of biologically active carbaglycosylamines: From glycosidase inhibitors to pharmacological chaperones.

For over 50 years, our group has been involved in synthetic studies on biologically active cyclitols including carbasugars. Among a variety of compounds synthesized, this review focuses on carbaglycosylamine glycosidase inhibitors, highlighting the following: (1) the naturally occurring N-linked carbaoligosaccharide α-amylase inhibitor acarbose and related compounds; (2) the novel synthetic β-glycosidase inhibitors, 1'-epi-acarviosin and its 6-hydroxy analogue as well as β-valienaminylceramide and its 4'-epimer; (3) the discovery of the β-glycosidase inhibitors with chaperone activity, N-octyl-β-valienamine (NOV) and its 4-epimer (NOEV); and (4) the recent development of the potential pharmacological chaperone N-alkyl-conduramine F-4 derivatives.

Visible room-temperature phosphorescence of pure organic crystals via a radical-ion-pair mechanism.

The afterglow of phosphorescent compounds can be distinguished from background fluorescence and scattered light by a time-resolved observation, which is a beneficial property for bioimaging. Phosphorescence emission accompanies spin-forbidden transitions from an excited singlet state through an excited triplet state to a ground singlet state. Since these intersystem crossings are facilitated usually by the heavy-atom effect, metal-free organic solids are seldom phosphorescent, although these solids have recently been refurbished as low-cost, eco-friendly phosphorescent materials.

Concise syntheses of potent chaperone drug candidates, N-octyl-4-epi-β-valinenamine (NOEV) and its 6-deoxy derivative, from (+)-proto-quercitol.

Described are the efficient syntheses of β-galactose-type unsaturated carbasugar amine, N-octyl-4-epi-β-valienamine (1a, NOEV) and 6-deoxy NOEV (12), starting from (+)-proto-quercitol (2), which is readily provided by the bioconversion of myo-inositol. NOEV is a potent chemical chaperone drug candidate for G(M1)-gangliosidosis. An intermediate alkadiene benzoate was prepared from 2 in five steps, with the key step being a Wittig reaction with an enol ester.

Transformation of quercitols into 4-methylenecyclohex-5-ene-1,2,3-triol derivatives, precursors for the chemical chaperones N-octyl-4-epi-β-valienamine (NOEV) and N-octyl-β-valienamine (NOV).

(+)-proto-Quercitol (1) and (-)-vibo-quercitol (2), both of which could be readily prepared by the bioconversion of myo-inositol, were successfully converted into the corresponding 4-methylenecyclohex-5-ene-1,2,3-triol derivatives. These compounds were demonstrated to be suitable precursors, preserving their configurations, for bioactive carba-aminosugars such as the potent chemical chaperone drug candidates, N-octyl-4-epi-β-valienamine (NOEV, 3) and N-octyl-β-valienamine (NOV, 4).

Positive association of common variants in CD36 with neovascular age-related macular degeneration.

Age-related macular degeneration (AMD) is a leading cause of legal blindness among older individuals of industrialized countries. In neovascular AMD, which is an advanced stage of AMD, choroidal neovascularization develops underneath the macula and destroys central vision. Oxidative stress is a hypothesized pathway for the pathophysiology of AMD.

Role of RDBP and SKIV2L variants in the major histocompatibility complex class III region in polypoidal choroidal vasculopathy etiology.

Purpose: To investigate whether polymorphisms in 4 tightly linked genes of the major histocompatibility complex class III--complement component 2 (C2), complement factor B (CFB), RD RNA-binding protein (RDBP), and superkiller viralicidic activity 2-like (SKIV2L)--are associated with polypoidal choroidal vasculopathy (PCV).

Design: Cross-sectional study.

Participants: A case-control group of 136 PCV subjects and 183 unrelated controls.

Coding variant Met72Thr in the PEDF gene and risk of neovascular age-related macular degeneration and polypoidal choroidal vasculopathy.

Purpose: Using a candidate-gene approach, a recent case-control study identified a previously unknown association between neovascular age-related macular degeneration (AMD) and the coding Met72Thr variant in the pigment epithelium-derived factor (PEDF) gene in a Taiwan Chinese population. However, a subsequent replication study failed to see this association in a white European population. We noted an important difference in the sample ascertainment scheme between these two studies.

Coding variant I62V in the complement factor H gene is strongly associated with polypoidal choroidal vasculopathy.

Purpose: To investigate whether variants in the complement factor H (CFH) gene are associated with polypoidal choroidal vasculopathy (PCV).

Design: Cross-sectional study.

Participants: A case-control group of 130 PCV subjects and 173 unrelated controls.

Lack of association of CPT1A polymorphisms or haplotypes on hepatic lipid content or insulin resistance in Japanese individuals with type 2 diabetes mellitus.

Accumulation of fat in the liver is associated with insulin resistance and type 2 diabetes mellitus. The carnitine palmitoyltransferase (CPT) enzyme system facilitates the transport of long-chain fatty acids into mitochondria, and the gene for the hepatic isoform of CPT1 (CPT1A) is a candidate gene for metabolic disorders such as insulin resistance associated with fatty liver. We have now investigated the contribution of the CPT1A locus to hepatic lipid content (HLC), insulin resistance, and susceptibility to type 2 diabetes mellitus.

Combination of multiple genetic risk factors is synergistically associated with carotid atherosclerosis in Japanese subjects with type 2 diabetes.

Objective: Several genetic risk factors, such as single nucleotide polymorphisms (SNPs), in candidate genes have been reported to be responsible for intima-media thickness (IMT), which is one of the surrogate end points of cardiovascular events. However, the synergistic effects of SNPs have not been evaluated in detail.

Research Design And Methods: We measured the average IMT of the common and internal carotid artery in Japanese type 2 diabetic patients (n = 690) (>50 years old) using ultrasonography.

Unified method for Bayesian calculation of genetic risk.

Bayesian inference has been used for genetic risk calculation. In this traditional method, inheritance events are divided into a number of cases under the inheritance model, and some elements of the inheritance model are usually disregarded. We developed a genetic risk calculation program, GRISK, which contains an improved Bayesian risk calculation algorithm to express the outcome of inheritance events with inheritance vectors, a set of ordered genotypes of founders, and mutation vectors, which represent a new idea for description of mutations in a pedigree.

Association of the -112A>C polymorphism of the uncoupling protein 1 gene with insulin resistance in Japanese individuals with type 2 diabetes.

The -112A>C polymorphism (rs10011540) of the gene for uncoupling protein 1 (UCP1) has been associated with type 2 diabetes mellitus in Japanese individuals. The aim of the present study was to investigate the effects of this polymorphism, as well as the well-known -3826A>G polymorphism (rs1800592), on clinical characteristics of type 2 diabetes. We determined the genotypes of the two polymorphisms in 93 Japanese patients with type 2 diabetes.

Division of linkage disequilibrium between absolute linkage disequilibrium and linkage equilibrium.

Linkage disequilibrium is the association between alleles in the allele distributions across linked loci and is intermediate in character between the dependence and the independence of allele distribution. This ambivalence makes linkage disequilibrium difficult to understand and to treat mathematically. To overcome this difficulty, an attempt was made to divide linkage disequilibrium between absolute linkage disequilibrium, which is a complete dependence of allele distribution, and linkage equilibrium, which is a complete independence.

Identification of two novel mutations in adenine phosphoribosyltransferase gene in patients with 2,8-dihydroxyadenine urolithiasis.

Five mutations in the adenine phosphoribosyltransferase (APRT) gene have been described in Japanese patients with APRT deficiency. We investigated the APRT gene from three patients with APRT deficiency and two novel mutations, G133D and V84M, were determined.

Comparison between various strategies for the disease-gene mapping using linkage disequilibrium analyses: studies on adenine phosphoribosyltransferase deficiency used as an example.

Recently, linkage disequilibrium analyses have been used to detect disease-causing loci based on the common disease-common variant hypothesis. To see what methods can effectively identify the genes, we have to apply them to the practical data obtained from the human population. We extensively performed linkage disequilibrium and haplotype analyses on adenine phosphoribosyltransferase ( APRT) genes in both control and deficient subjects.

Does phosphatidylinositol 3-kinase play a role in insulin-induced outgrowth of pseudopodial cables in cultured cells derived from micromeres of sea urchin embryos?

Cultured cells derived from micromeres isolated from sea urchin embryos at the 16-cell stage, which have insulin receptors, undergo pseudopodial cable growth and spicule rod formation in culture with horse serum and only cable growth in culture with insulin. Genistein, an inhibitor of protein tyrosine kinase, and wortmannin, an inhibitor of phosphatidylinositol 3-kinase (PI3kinase), inhibited pseudopodial cable growth in micromere-derived cells cultured with insulin and also growth accompanied by spicule rod formation in horse serum-treated cells. The PI3kinase activity in the immunoprecipitates obtained by anti-phosphotyrosine antibody from the cells cultured with insulin was higher than that in cells cultured without insulin or with insulin and genistein.

Several Cell Responses to Insulin of Cultured Cells Derived from Micromeres, Isolated from Sea Urchin Embryos at the 16 Cell Stage: (Sea urchin/development/morphogenesis/insulin/micromere).

In micromere-derived cells of sea urchin embryos, treatment with insulin started for up to 24 h during culture at 20°C resulted in augmentation of P incorporation into protein (protein phosphorylation) followed by activation of P incorporation into RNA (RNA synthesis) and then induced pseudopodial cable growth, accompanied by considerable decreases in the rates of protein phosphorylation and RNA synthesis. This augmentation of RNA synthesis and cable growth induced by insulin were blocked by H-7, which inhibited protein phosphorylation, and were also inhibited by actinomycin D without any inhibition of protein phosphorylation. Similar results were obtained on treatment with horse serum, found to contain insulin-like compounds.

Changes in Insulin-Binding Capacity of the Plasma Membrane Fraction during Culture in vitro of Cells Derived from Micromeres of 16-Cell-Stage Sea Urchin Embryos: (sea urchin/development/micromere/insulin/insulin receptor).

In cultured cells derived from isolated micromeres of 16-cell stage sea urchin embryos, which undergo insulin-induced pseudopodial cable growth, specific and reversible insulin binding by a 52-kDa protein, probably an insulin receptor in the plasma membrane, is augmented during 5 h of culture without any change in the dissociation constant (Kuno et al : 1994). The increase in insulin-binding capacity in micromere-derived cells was only minimally blocked by actinomycin D and cycloheximide, which inhibited [U- H]uridine incorporation into RNA and [ S]methionine incorporation into protein, respectively. Insulin binding capacity was found in the plasma membrane fraction and the microsome fraction of isolated micromeres.

Insulin-Induced Outgrowth of Pseudopodial Cables from Cultured Micromere-Derived Cells Isolated from Sea Urchin Embryos at the 16 Cell Stage, with Special Reference to the Insulin-Receptor.: (sea urchin/micromere/insulin/psedopodial cable/receptor).

Cultured cells derived from micromeres isolated from sea urchin embryos at the 16 cell stage are known to show outgrowth of pseudopodial cables followed by spicule rod formation when cultured in the presence of horse serum. Micromere-derived cells cultured with bovine insulin showed pseudopodial cable growth but did not produce spicule rods. Micromere-derived cells reversibly bound to insulin through out the period between 3 and 20 hr of culture.