Search PubMed⌕ Search

Biomedical subjects

T Ogihara

Publications and source records attributed to T Ogihara.

At least 181 records · Page 10Linked to original sources

[Insulin].

Explore the source record for details and available documents.

Humans↗

Gene therapy as a potential treatment for restenosis and myocardial infarction.

Cardiovascular disease is the leading cause of mortality and morbidity in developed countries. Most conventional therapy is inefficient and tends to treat the symptoms rather than the underlying causes of the disorder. Gene therapy offers a novel approach for the prevention and treatment of cardiovascular diseases. Gene transfer into somatic cells to interfere with the pathogenetic processes contributing to cardiovascular disease may provide such a novel approach for better prevention and treatment of cardiovascular disorders. The major development of gene transfer has importantly contributed to intense investigation of the potential of gene therapy in cardiovascular medicine. The amazing advances in molecular biology have provided a dramatic improvement in the technology that is necessary to transfer target genes into somatic cells. Recently, transfection of cis element double-stranded oligonucleotides (ODN), referred to as decoy ODN, has been reported to be a powerful tool in a new class of antigene strategies for gene therapy. In this article, we review the successful treatment of restenosis and myocardial infarction using the decoy strategy combined with an efficient gene transfer method.

Journal Article↗

Human prostacyclin synthase gene and hypertension : the Suita Study.

BACKGROUND: Prostacyclin (prostaglandin I(2)) is a strong vasodilator that inhibits the growth of vascular smooth muscle cells and is also the most potent endogenous inhibitor of platelet aggregation. Therefore, it has been considered to play an important roles in cardiovascular disease. On the basis of the hypothesis that variations of the prostacyclin synthase gene may also play an important role in human cardiovascular disease, we performed a screening for variations in the human prostacyclin synthase gene. METHODS AND RESULTS: We have detected a repeat polymorphism in the promoter region of the human prostacyclin synthase gene. The number of 9-bp (CCGCCAGCC) repeats in the promoter region, which encodes a tandem repeat of Sp1 transcriptional binding sites, varied between 3 and 7 in Japanese subjects. Luciferase reporter analysis indicated that the alleles of 3 and 4 repeats (R3 and R4, respectively) had less promoter activity in cultured human umbilical vein endothelial cells. We then investigated the possible association of this repeat polymorphism with blood pressure in a large population-based sample (the Suita Study), which consisted of 4971 Japanese participants. Multivariate models indicated that participants with the R3R3, R3R4, or R4R4 genotype (SS genotype, n=80) had significantly higher systolic pressure (P=0.0133) and pulse pressure (P=0.0005). The odds ratio of hypertension (140/90 mm Hg) for the SS genotype was 1.942 (95% confidence interval 3.20 to 1.19, P=0.0084). CONCLUSIONS: Repeat polymorphism of the human prostacyclin synthase gene seems to be a risk factor for higher pulse pressure and is consequently a risk factor for systolic hypertension in the Japanese population.

Adult↗

Potential role of hepatocyte growth factor, a novel angiogenic growth factor, in peripheral arterial disease: downregulation of HGF in response to hypoxia in vascular cells.

BACKGROUND: Although hepatocyte growth factor (HGF), a novel angiogenic growth factor, plays an important role in angiogenesis, regulation of local HGF production under hypoxia has not yet been clarified in vascular smooth muscle cells (VSMC) and endothelial cells (EC). Thus, we have studied the role of HGF in hypoxia-induced endothelial injury and the regulation of local vascular HGF expression in response to hypoxia. METHODS AND RESULTS: HGF attenuated hypoxia-induced endothelial cell death. Importantly, hypoxic treatment of EC resulted in a significant decrease in local HGF production according to the severity of hypoxia and increased VEGF. Similarly, hypoxia significantly decreased in mRNA and protein of HGF and increased VEGF production in VSMC. In organ culture system, local HGF production was also significantly decreased by hypoxia (P<0.01). Downregulation of HGF by hypoxia is due to a significant decrease in cAMP, as hypoxic treatment decreased cAMP, a stimulator of HGF. Although active TGF-beta, a suppressor of HGF, was increased at 72 hours after hypoxic treatment, treatment of anti-TGF-beta antibody did not attenuate decreased HGF production. Finally, rHGF was intra-arterially administered into unilateral hind limb ischemia rabbits, to evaluate in vivo angiogenic activity. Of importance, a single intra-arterial administration of rHGF reduced severe necrosis due to ischemia in rabbit muscle, accompanied by a significant increase in angiographic score (P<0.01). CONCLUSIONS: Overall, these data demonstrated that hypoxic treatment of vascular cells significantly downregulated HGF production due to decreased cAMP, suggesting their potential roles in the pathophysiology of ischemic diseases. Moreover, administration of rHGF induced therapeutic angiogenesis, accompanied by improvement of necrotic changes in the ischemic hind limb model, as cytokine supplement therapy for peripheral arterial disease.

Animals↗

Angiotensinogen gene-activating elements regulate blood pressure in the brain.

Although the angiotensinogen gene is a possible candidate as a determinant of hypertension, the molecular mechanisms of tissue angiotensinogen gene regulation have yet to be clarified. We identified essential transcription regulators of angiotensinogen production in the central nervous system using synthetic double-stranded oligodeoxynucleotides (ODNs) as "decoy" cis elements to block the binding of nuclear factors to promoter regions of the targeted gene. Using a gel mobility shift assay, angiotensinogen gene-activating element (AGE) 2 binding protein was detected in the brain nuclear extracts of both spontaneously hypertensive rats (SHRs) and normotensive Wistar Kyoto rats (WKYs). Importantly, the binding activity of AGE 2 and angiotensinogen mRNA level were significantly higher in the brain of SHRs than in that of WKYs. Using the decoy approach, we demonstrated a significant decrease in the blood pressure of SHRs by transfection of AGE 2 decoy, but not mismatched, ODNs into the lateral cerebroventricle, accompanied by a significant decrease in brain angiotensinogen concentration and mRNA, and angiotensin II level. That these effects, demonstrated herein, are due to central effects is confirmed by the fact that no changes in circulating levels of angiotensinogen or angiotensin II concentrations were observed. Notably, AGE 2 decoy ODNs did not decrease the blood pressure of WKYs. We conclude that the abnormal expression of AGE 2 binding protein in the central nervous system plays a crucial role in high blood pressure of a genetically hypertensive rat model.

Angiotensinogen↗

p85/p110-type phosphatidylinositol kinase phosphorylates not only the D-3, but also the D-4 position of the inositol ring.

Activation of p85/p110-type phosphatidylinositol (PI) kinase has been implicated in various cellular activities. This PI kinase phosphorylates the D-4 position with a similar or higher efficiency than the D-3 position when trichloroacetic acid-treated cell membrane is used as a substrate, although it phosphorylates almost exclusively the D-3 position of the inositol ring in phosphoinositides when purified PI is used as a substrate. Furthermore, the lipid kinase activities of p110 for both the D-3 and D-4 positions were completely abolished by introducing kinase-dead point mutations in their lipid kinase domains (DeltaKinalpha and DeltaKinbeta, respectively). In addition, both PI 3- and PI 4-kinase activities of p110alpha and p110beta immunoprecipitates were similarly inhibited by either wortmannin or LY294002, specific inhibitors of p110. Insulin induced phosphorylation of not only the D-3 position, but also the D-4 position. Indeed, overexpression of p110 in Sf9 or 3T3-L1 cells induced marked phosphorylation of the D-4 position to a level comparable to or much greater than that of D-3, whereas inhibition of endogenous p85/p110-type PI kinase via overexpression of dominant-negative p85alpha (Deltap85alpha) in 3T3-L1 adipocytes abolished insulin-induced synthesis of both. Thus, p85/p110-type PI kinase phosphorylates the D-4 position of phosphoinositides more efficiently than the D-3 position in vivo, and each of the D-3- or D-4-phosphorylated phosphoinositides may transmit signals downstream.

1-Phosphatidylinositol 4-Kinase↗

Transcription factor decoy to study the molecular mechanism of negative regulation of renin gene expression in the liver in vivo.

Renin is synthesized in high quantities in the juxtaglomerular cells of the kidney, but little or none is synthesized in the liver. Our previous in vitro and biochemical studies have demonstrated that tissue-specific expression of the mouse renin gene is regulated by the specific interaction between negative regulatory element (NRE) in the 5'-flanking region of the renin gene and NRE binding protein (NREB). In this study, we examined the hypothesis that this interaction between the NRE in the promoter region of the rat renin gene and the NREB in the liver contributes to the suppressed renin gene expression in this tissue in vivo. We used in vivo transfection of NRE transcription factor decoy (TFD) double-stranded oligonucleotide into the rat liver via portal vein infusion. A gel mobility shift assay showed that transfected NRE TFD blocked endogenous NREB binding with the rat renin gene. This resulted in enhanced hepatic renin mRNA expression, immunohistochemical detection of renin in the liver, and consequently, increased plasma renin concentration. Taken together, these results document the importance of NREB in the inhibition of renin gene expression in rat liver in vivo and suggest the possibility of in vivo renin gene modulation by the TFD approach.

Animals↗