Atorvastatin prevents endothelial dysfunction in high glucose condition through Skp2-mediated degradation of FOXO1 and ICAM-1.

OBJECTIVE: The 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor atorvastatin has been reported to exert vasculo-protective action in diabetes. We investigated the vasculo-protective mechanism of atorvastatin by evaluating its effect on two major pathogenic molecules, FOXO1 and ICAM1, mediated by S-phase kinase-associated protein 2 (Skp2) in diabetic endothelial dysfunction. APPROACH AND RESULTS: [1] FOXO1: Hyperglycemic condition increased FOXO1 protein level in endothelial cells, which was reversed by atorvastatin. This atorvastatin effect was obliterated by treatment of protease inhibitor, suggesting that atorvastatin induces degradation of FOXO1. Immunoprecipitation showed that atorvastatin facilitated the binding of Skp2 to FOXO1, leading to ubiquitination and degradation of FOXO1. [2] ICAM-1: Increased ICAM1 in high glucose condition was reduced by atorvastatin. But this effect of atorvastatin was obliterated when Skp2 was inhibited, suggesting that atorvastatin enhances binding of Skp2 to ICAM1 leading to degradation. Actually, ubiquitination and degradation of ICAM-1 were reduced when Skp2 was inhibited. In vitro monocyte adhesion assay revealed that atorvastatin reduced monocyte adhesion on endothelial cells in high glucose condition, which was reversed by Skp2 knock-down. CONCLUSION: Atorvastatin strengthens Skp2 binding to FOXO1 or ICAM1, leading to ubiquitination and degradation. Skp2-dependent ubiquitination of major pathogenic molecules is the key mechanism for statin's protective effect on endothelial function in diabetes.

Fluorescent probes designed for detecting human serum albumin on the basis of its pseudo-esterase activity.

We developed activity-based fluorescent probes for detecting human serum albumin (HSA) on the basis of its pseudo-esterase activity. These probes could also detect HSA in blood-contaminated tissue samples.

Gas chromatographic-mass spectrometric analyses of cholesterol and its precursors in rat plasma as tert-butyldimethylsilyl derivatives.

BACKGROUND: Cholesterol and its metabolic precursors occurring in metabolic pathways are important biochemical indicators in pathological conditions. METHODS: A method for the simultaneous determination of cholesterol and its metabolic precursors, such as lanosterol and 7-dehydrocholesterol, in rat plasma is demonstrated. It involves their extraction after saponification, followed by conversion to tert-butyldimethylsilyl (TBDMS) derivatives for analysis by gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring (SIM) mode (GC-SIM-MS). RESULTS: The characteristic fragment ions of [M-57], m/z 443, 483, and 441 permitted the accurate and selective detection of cholesterol and its precursors in rat plasma. The whole procedure of TBDMS derivatization, with subsequent GC-SIM-MS analysis, was linear (r>or=0.9994), reproducible (% relative standard deviation=2.2 to 7.5), and accurate (% relative error=-5.6 to 7.7), with detection limits of 0.02 to 0.07 ng/ml. Recoveries were measured to be ranged from 89.5 to 95.4%. CONCLUSION: The present method was useful for the quantification of cholesterol and its precursors in rat plasma samples of 1 microl.

Rapid determination of floral aroma compounds of lilac blossom by fast gas chromatography combined with surface acoustic wave sensor.

A novel analytical method using fast gas chromatography combined with surface acoustic wave sensor (GC/SAW) has been developed for the detection of volatile aroma compounds emanated from lilac blossom (Syringa species: Syringa vulgaris variginata and Syringa dilatata). GC/SAW could detect and quantify various fragrance emitted from lilac blossom, enabling to provide fragrance pattern analysis results. The fragrance pattern analysis could easily characterize the delicate differences in aromas caused by the substantial difference of chemical composition according to different color and shape of petals. Moreover, the method validation of GC/SAW was performed for the purpose of volatile floral actual aroma analysis, achieving a high reproducibility and excellent sensitivity. From the validation results, GC/SAW could serve as an alternative analytical technique for the analysis of volatile floral actual aroma of lilac. In addition, headspace solid-phase microextraction (HS-SPME) GC-MS was employed to further confirm the identification of fragrances emitted from lilac blossom and compared to GC/SAW.