The retinol-retinoic acid metabolic pathway is impaired in the lumbar spine of a rat model of congenital kyphoscoliosis

Although congenital scoliosis is defined as a genetic disease characterized by a congenital and abnormal curvature of the spinal vertebrae, our knowledge of the genetic underpinnings of the disease is insufficient. We herein show that the downregulation of the retinol-retinoic acid metabolism pathway is involved in the pathogenesis of congenital scoliosis. By analyzing DNA microarray data, we found that the expression levels of genes associated with the retinol metabolism pathway were decreased in the lumbar spine of Ishibashi rats (IS), a rat model of congenital kyphoscoliosis. The expression of Adh1 and Aldh1a2 (alcohol dehydrogenase), two enzymes that convert retinol to retinoic acid in this pathway, were decreased at both the gene and protein levels. Rarα, a receptor of retinoic acid and bone morphogenetic protein 2, which play a central role in bone formation and are located downstream of this pathway, were also downregulated. Interestingly, the serum retinol levels of IS rats were higher than those of wild-type control rats. These results indicate that the adequate conversion from retinol to retinoic acid is extremely important in the regulation of normal bone formation and it may also be a key factor for understanding the pathogenesis of congenital scoliosis.     

Effect of IL-12 encoding plasmid administration on tight-skin mouse

The tight-skin (Tsk/+) mutant mice, a putative murine model of scleroderma, are characterized by the excessive deposition of collagen and the presence of antinuclear antibodies. Type 2 cytokines, such as IL-4 and IL-6, are capable of regulating the synthesis of various matrix molecules, including type I collagen, by fibroblasts. IL-12 is well known to induce type 1 cytokine production and to reduce type 2 activity. Here, we examined the effect of IL-12 encoding plasmid (pCAGGSIL-12) on the disease progression of Tsk/+ mice. pCAGGSIL-12 plasmid or pCAGGS parental vector was injected intramuscularly 7 times at 3 week intervals into Tsk/+ mice. One week after the last injection, pCAGGSIL-12 administered Tsk/+ mice exhibited a marked decrease in the skin thickness compared with the mice treated with pCAGGS vector. The serum levels of antinuclear antibodies were diminished in pCAGGSIL-12 treated mice. IL-4 production by spleen cells from pCAGGSIL-12 plasmid treated mice was significantly lower than that from vector treated mice. These results indicate that pCAGGSIL-12 administration into Tsk/+ mice had beneficial effects in preventing the collagen accumulation in the skin and suppressing the autoimmunity via improvement of Th1/Th2 balance. The present study suggests that the IL-12 encoding plasmid administration might have a therapeutic effect on systemic sclerosis.     

Protamine-modified DDAB lipid vesicles promote gene transfer in the presence of serum

Cationic lipid vesicle-mediated gene transfer has become common for in vitro gene delivery. However, the transfection efficiency is often impaired by serum. DDAB (dimethyldioctadecyl ammonium bromide) lipid vesicle-mediated gene transfer, which we previously reported, has the same problem. To overcome this obstacle, we here report a novel transfection vehicle using protamine-modified DDAB lipid vesicles. While free protamine was simply added to the DNA/lipid complex in the previous study, in the present method the protamine is chemically conjugated to stearic acid and incorporated into DDAB lipid vesicles. Gene transfer was not significantly inhibited in 10% serum-containing medium by this method for the transfection of cultured cells. Protamine-modified DDAB lipid vesicles also enhanced virus transduction efficiency in the presence of serum using a replication-defective retroviral vector. Furthermore, the vesicles allowed efficient gene transfer for avian embryos in vivo. These results indicate that the method is useful for the production of transgenic animals and gene therapy.     

Chemo-enzymatic synthesis and structure-activity study of artificially N-glycosylated eel calcitonin derivatives with a complex type oligosaccharide

Starting from N-glycosylated eel calcitonin derivatives that contain an N-acetyl-D-glucosamine residue specifically at the 3rd, 14th, 20th or 26th amino acid residue, corresponding glycopeptides with a complex-type oligosaccharide attached to the respective amino acid residue were synthesized by means of a transglycosylation reaction catalyzed by an endo-beta-N-acetylglucosaminidase from Mucor hiemalis . The use of a recombinant enzyme and an excess of a glycosyl donor led to a yield in excess of 60%. Calcitonin derivatives containing truncated oligosaccharides were also prepared via digestion of the complex-type N-glycan with exoglycosidases. Using these N-glycosylated calcitonin derivatives, the effect of carbohydrate structure and glycosylation site on the three-dimensional structure and the biological activity of the peptide were studied. The conformation of the peptide backbone did not change irrespective of the carbohydrate structure or the glycosylation site. However, hypocalcemic activity, calcitonin-receptor binding activity and the biodistribution of the derivatives were affected by the glycosylation and were dependent on both the carbohydrate structure and the glycosylation site. Although the larger oligosaccharides tended to hinder receptor binding, the biodistribution altered by N-glycosylation appeared to enhance the hypocalcemic activity in some cases, and the magnitude of the effect was dependent on the site of glycosylation.     

Hypoxia-inducible factor 1 mediates upregulation of telomerase (hTERT)

Hypoxia occurs during the development of the placenta in the first trimester and correlates with both trophoblast differentiation and the induction of telomerase activity through hTERT expression. We sought to determine the mechanism of regulation of hTERT expression during hypoxia. We show that hypoxia-inducible factor 1alpha (HIF-1alpha) and hTERT expression in the human placenta decrease with gestational age and that these are overexpressed in preeclamptic placenta, a major complication of pregnancy. Hypoxia not only transactivates the hTERT promoter activity but also enhances endogenous hTERT expression. The hTERT promoter region between -165 and +51 contains two HIF-1 consensus motifs, and in vitro reporter assays show that these are essential for hTERT transactivation by HIF-1. Introduction of an antisense oligonucleotide for HIF-1 diminishes hTERT expression during hypoxia, indicating that upregulation of hTERT by hypoxia is directly mediated through HIF-1. Our results provide persuasive evidence that the regulation of hTERT promoter activity by HIF-1 represents a mechanism for trophoblast growth during hypoxia and suggests that this may be a generalized response to hypoxia in various human disorders including resistance to cancer therapeutics by upregulating telomerase.     

Imprinted polymer layer for recognizing double-stranded DNA

A method of preparing a thin polymer layer able to recognize double-stranded DNA (dsDNA) was developed by using 2-vinyl-4,6-diamino-1,3,5-triazine (VDAT) as a functional monomer for creating a DNA-imprinted polymer. The formation of hydrogen bonds between VDAT and A-T base pairs in dsDNA was confirmed by measuring the effects of VDAT on the melting point and the NMR and CD spectra of dsDNA. An imprinted polymer that can recognize dsDNA of the verotoxin gene was prepared by polymerizing VDAT, acrylamide, a crosslinking agent, and the template verotoxin dsDNA on a silanized glass surface. The specificity of this polymer layer for binding verotoxin dsDNA was investigated by using fluorescent-labelled dsDNAs. The fluorescence intensity of the polymer layer after binding verotoxin dsDNA was twice as high as after binding oligo(dG)-oligo(dC), indicating that verotoxin dsDNA was preferentially bound to the polymer imprinted with verotoxin dsDNA. The kinetics of verotoxin dsDNA binding to the imprinted polymer were analyzed by surface plasmon resonance measurements. The dissociation constant (KD) was low, of the order of 10(-9)M.     

The inhibitory effect of luteolin-7-O-glucoside on the formation of pentyl and 7-carboxyheptyl radicals from 13-hydroperoxy-9,11-octadecadienoic acid in the presence of iron(II) ions

A flavone glucoside, luteolin-7-O-glucoside (luteolin-7-G) inhibited the formation of pentyl and 7-carboxyheptyl radicals in the reaction of 13-hydroperoxy-9,11-octadecadienoic (13-HPODE) acid with iron(II) ions. The inhibitory effect of luteolin-7-G was diminished in the presence of EDTA. These results indicated that the inhibitory effects of luteolin-7-G occur partly through the chelation of iron ions. Measurement of visible spectra also showed that luteolin-7-G chelates iron ions. On the other hand, luteolin-7-G did not inhibit the reaction under anaerobic conditions, suggesting that oxygen molecules participate in the inhibition. Oxygen consumption measurements showed that the luteolin-7-G/iron ion complexes react with oxygen molecules in competition with 13-HPODE acid, and free iron ions exclusively react with 13-HPODE acid. The reaction of luteolin-7-G/iron ion complexes with oxygen molecules possibly diminishes the formation of pentyl and 7-carboxyheptyl radicals.     

A rapid biosensor chip assay for measuring of telomerase activity using surface plasmon resonance

Considerable interest has been focused on telomerase because of its potential use in assays for cancer diagnosis, and for anti-telomerase drugs as a strategy for cancer chemotherapy. A number of assays based on the polymerase chain reaction (PCR) have been developed for evaluation of telomerase activity. To overcome the disadvantages of the conventional telomerase assay [telomeric repeat amplification protocol (TRAP)] related to PCR artifacts and troublesome post-PCR procedures, we have developed a telomeric repeat elongation (TRE) assay which directly measures telomerase activity as the telomeric elongation rate by biosensor technology using surface plasmon resonance (SPR). 5′-Biotinylated oligomers containing telomeric repeats were immobilized on streptavidin-pretreated dextran sensor surfaces in situ using the BIACORE apparatus. Subsequently, the oligomers associated with the telomerase extracts were elongated in the BIACORE apparatus. The rate of TRE was calculated by measuring the SPR signals. We examined elongation rates by the TRE assay in 18 cancer and three normal human fibroblast cell lines, and 12 human primary carcinomas and matching normal tissues. The elongation rates increased in a concentration- and time-dependent manner. Those of cancer cells were two to 10 times higher than fibroblast cell lines and normal tissues. Telomerase activities and its inhibitory effects of anti-telomerase agents as measured by both the TRE and TRAP assays showed a good correlation. Our assay allows precise quantitative comparison of a wide range of human cells from somatic cells to carcinoma cells. TRE assay is suitable for practical use in the assessment of telomerase activity in preclinical and clinical trials of telomerase-based therapies, because of its reproducibility, rapidity and simplicity.     

Synthesis and structure-activity relationship for new series of 4-phenoxyquinoline derivatives as specific inhibitors of platelet-derived growth factor receptor tyrosine kinase

We discovered a new series of 4-phenoxyquinoline derivatives as potent and selective inhibitors of the platelet-derived growth factor receptor (PDGFr) tyrosine kinase. We researched the highly potent and selective inhibitors on the basis of both PDGFr and epidermal growth factor receptor (EGFr) inhibitory activity. First, we found a compound, Ki6783 (1), which inhibited PDGFr autophosphorylation at 0.13 microM, but it did not inhibit EGFr autophosphorylation at 100 microM. After extensive explorations, we found the two desired compounds, Ki6896 (2) and Ki6945 (3), which are substituted by benzoyl and benzamide at the 4-position of the phenoxy group on 4-phenoxyquinoline, respectively. These inhibitory activities were 0.31 and 0.050 microM, respectively, but neither of them inhibited EGFr autophosphorylation at 100 microM. We further investigated the profile of both compounds toward various tyrosine and serine/threonine kinases. The three compounds specifically inhibited PDGFr rather than the other kinases.