Objective-Endothelial nitric oxide synthase (eNOS) activity is supported by tetrahydrobiopterin (BH4), which appears to be important for generating protective NO but decreases uncoupling formation of superoxide. We investigated the effects of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, or statins, in terms of BH4 metabolism in human umbilical vein endothelial cells (HUVECs). Methods and Results-We measured the mRNA levels of GTP cyclohydrolase I (GTPCH), the rate-limiting enzyme in the first step of de novo BH4 synthesis, by real-time polymerase chain reaction. The mRNA of GTPCH, as well as of eNOS, was upregulated in HUVECs treated with cerivastatin. This increase was time and dose dependent. Fluvastatin was also observed to enhance GTPCH and eNOS mRNA levels. In parallel with this observation, cerivastatin increased intracellular BH4. Incubating HUVECs with tumor necrosis factor (TNF-␣) was observed to increase GTPCH mRNA while decreasing eNOS mRNA. In the presence of cerivastatin, the TNF-␣-mediated increase in GTPCH mRNA was enhanced, and the TNF-␣-mediated decrease in eNOS mRNA was attenuated. Cerivastatin increased the stability of eNOS mRNA. However, it did not alter the stability of GTPCH mRNA but increased GTPCH gene transcription, as shown by nuclear run-on assays. Preteatment of HUVECs with the selective GTPCH inhibitor, 2,4-diamino-6-hydroxypyrimidine, caused a decrease in intracellular BH4 and decreased citrulline formation after stimulation with ionomycin. Furthermore, the potentiating effect of cerivastatin was decreased by limiting the cellular availability of BH4. Conclusions-Our data demonstrate that statins elevate GTPCH mRNA, thereby increasing BH4 levels in vascular endothelial cells. In addition to augmenting eNOS expression, statins potentiate GTPCH gene expression and BH4 synthesis, thereby increasing NO production and preventing relative shortages of BH4. Key Words: statins Ⅲ cytokines Ⅲ nitric oxide Ⅲ tetrahydrobiopterin Ⅲ endothelial cells T he effectiveness and speed with which 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statin medications) can favorably influence vascular biology by mechanisms other than causing a reduction in plasma cholesterol have been demonstrated in a number of reports. [1][2][3][4][5][6] During the past several years, numerous additional effects of statins on vascular cells have been identified, which appear to modulate atherogenesis, plaque rupture, or thrombosis. Some of these appear to operate independently of the cholesterol-lowering mechanism. 4,5 For example, statins may upregulate nitric oxide (NO) expression by interfering with posttranscriptional regulation of endothelial NO synthase (eNOS). 7,8 Evidence regarding the importance of this mechanism in vivo was provided by the observation that statins inhibit ischemic cerebral stroke induced by occlusion of the middle cerebral artery in normal but not e-NOS-deficient mice. 9Tetrahydrobiopterin (BH4) is 1 of the most potent, naturally occurring reducing agents and ...

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Our findings suggest that the beneficial effects of cilostazol on endothelial function may be due to AMPK activation. Restoration of endothelial dysfunction in diabetic rats by cilostazol is at least partly attributed to amelioration of biopterin metabolism in the aorta.

YPEL5 is a member of the YPEL gene family that is highly conserved in the eukaryotic species and apparently involved in a certain cell division-related function. In this study, we examined the functional and phylogenetic aspects of YPEL5 protein in more detail. During cell cycle, YPEL5 protein was detected at different subcellular localizations; at interphase, it was located in the nucleus and centrosome, then it changed location sequentially to spindle poles, mitotic spindle, and spindle midzone during mitosis, and finally transferred to midbody at cytokinesis. Knockdown of YPEL5 function by siRNA or anti-sense morpholino oligonucleotide inhibited the growth of cultured COS-7 cells and early development of medaka fish embryos, indicating its involvement in cell cycle progression. Interestingly, RanBPM (Ran Binding Protein in the Microtubule organizing center, encoded by RANBP9) was identified as a YPEL5-binding protein by yeast two-hybrid method. A paralog of RanBPM, namely RanBP10 (encoded by RANBP10), was found to be another YPEL5-binding protein, and these two protein genes are highly conserved each other. Comparative genomic analysis allowed us to define a new gene family consisting of RanBPM and RanBP10, named Scorpin, providing a basis to better understand how they interact with YPEL5.

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ABSTRACT. Edema disease (ED) has become frequent in Japan, but no effective method for experimental infection has been developed. We report here the use of a capsule that resistant against gastric digestion to induce the ED in piglets. Four 21-day-old piglets were used. Shiga toxin 2e-producing Escherichia coli (STEC) cell pellet was encapsulated and administered orally. Two pigs received 1.0 × 10 10 CFU for two days, and the others received 3.9 × 10 8 CFU for three days. The high-dose group caused the typical clinical ED signs (palpebral edema or neurologic impairment). Eosinophil infiltration, swollen lymphoid follicles, and edema were observed in the ileum. The kidney had the thrombus in the glomerulus. KEY WORDS: edema disease, eosinophil infiltration, experimental infection.

Objective-Although it has been reported that oral administration of tetrahydrobiopterin (BH4) prevents endothelial dysfunction and vascular oxidative stress in various rat models, the effect of treatment with BH4 on atherogenesis remains unclear. Methods and Results-In this study, we investigated whether oral BH4 treatment might slow the progression of atherosclerosis using hypercholesterolemic apolipoprotein E-knockout mice. We report that ingesting BH4 in drinking water is sufficient to inhibit atherogenesis in mice. Furthermore, we report that BH4 treatment improves endothelial dysfunction and attenuates increased mRNA expression of NADPH oxidase components, as well as a number of inflammatory factors, such as LOX-1 and MCP-1, in the aortas of apolipoprotein E-knockout mice. Key Words: apolipoprotein E-knockout mouse Ⅲ atherosclerosis Ⅲ endothelial function Ⅲ tetrahydrobiopterin N itric oxide (NO) inhibits atherogenesis through a number of mechanisms, including anti-inflammatory, antithrombotic, antiproliferative, and antioxidant effects. 1 Loss of NO bioavailability is a cardinal feature of endothelial dysfunction 2 preceding the development of atherosclerosis, and is an independent risk factor for cardiovascular disease. 3,4 A critical determinant of endothelial nitric oxide synthase (eNOS) activity is the availability of the nitric oxide synthase (NOS) cofactor tetrahydrobiopterin (BH4). When BH4 levels are inadequate, the enzymatic reduction of molecular oxygen by eNOS is no longer coupled to L-arginine oxidation, resulting in superoxide, rather than NO, production, thereby inducing vascular oxidative stress and endothelial dysfunction. Conclusion-StrategiesIn hypercholesterolemic apolipoprotein E-knockout (ApoE-KO) mice, endothelium-dependent vascular relaxation is impaired, NO synthesis is reduced, and vascular superoxide production is increased. 5,6 Transgenic overexpression of eNOS in ApoE-KO mice surprisingly results in enhanced vascular superoxide production, reduced NO bioavailability, and accelerated atherosclerosis. 7 BH4 levels are reduced in the aortas of these mice compared with wild-type (WT) controls, but dietary BH4 supplementation reduces superoxide production and increases NO synthesis. Furthermore, transgenic overexpression of GTP-cyclohydrolase I, the ratelimiting enzyme of de novo BH4 synthesis, in ApoE-KO mice attenuates endothelial dysfunction and atherosclerosis. 8 In this model, endothelial cell BH4 levels are specifically increased without elevation of plasma BH4 levels. These results suggest that increased eNOS protein alone is insufficient to maintain NO synthesis in the setting of hypercholesterolemia, and that adequate BH4 levels are essential to prevent eNOS uncoupling where endothelial dysfunction exists. In contrast, van Haperen et al 9 also crossbred ApoE-KO mice with another line of eNOS transgenic mice that they created and reported that atherosclerotic lesion size was reduced by eNOS overexpression. Regarding the mechanisms, they cited the reductions of blood pressure a...