tosylphenylalanyl-chloromethyl-ketone and Hyperglycemia

The aim of the present study was to determine the correlation between angiogenesis and the differential expression of growth factors and their receptors when myocardial microvascular endothelial cells (MMVECs) were co-cultured with mast cell granules (MCGs) under hyperglycemic conditions. MMVECs and mast cells (MCs) were isolated from Wistar rats. An in vitro angiogenesis assay was used to observe any differences when MMVECs were co-cultured with MCGs in normal or hyperglycemic medium. The mRNA and protein expression of growth factors and their receptors were analyzed by real-time reverse transcription (RT)-PCR and western blot analysis. Real-time RT-PCR analysis demonstrated the upregulated mRNA and protein expression of vascular endothelial growth factor (VEGF) in the MMVECs; however, the expression of its receptor, fms-like tyrosine kinase-1 (Flt-1) and fetal liver kinase-1 (Flk‑1), decreased significantly, and the angiogenic ability of the MMVECs decreased under hyperglycemic conditions. The angiogenic ability of the MMVECs cultured under hyperglycemic conditions (even after the addition of MCGs) was inferior to that of the MMVECs cultured under normal glucose conditions. The specific inhibitor of tryptase, N-tosyl-L-lysine chloromethyl ketone (TLCK), suppressed angiogenesis regardless of the glucose concentration, and the specific inhibitor of chymase, N-tosyl-L-phenylalanyl chloromethyl ketone (TPCK), was not as effective as TLCK, which was mainly detected under hyperglycemic conditions. High glucose levels have a profound effect on angiogenesis; this effect may be more pronounced than the effects of MCGs on angiogenesis.

Topics: Animals; Coculture Techniques; Endothelial Cells; Gene Expression Regulation; Glucose; Hyperglycemia; Male; Mast Cells; Microvessels; Myocardium; Neovascularization, Physiologic; Rats; Rats, Wistar; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Tosyllysine Chloromethyl Ketone; Tosylphenylalanyl Chloromethyl Ketone; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factor Receptor-1; Vascular Endothelial Growth Factor Receptor-2; Wound Healing

High glucose promotes macrophage-derived foam cell formation involved in increased influx or reduced efflux of lipids. The aim of this study is to investigate the influence of hyperglycaemia on foam cell transformation of vascular smooth muscle cells (VSMCs) and possible mechanisms contributing to these effects.. The results showed that high glucose increased the expression of CD36, a regulator of lipid influx, and suppressed the expression and activity of the adenosine triphosphate-binding cassette (ABC) transporter ABCG1, a regulator of cholesterol efflux to high-density lipoprotein, in a dose- and time-dependent manner. However, cholesterol efflux to lipid-free apoAI was not impaired. VSMCs exposed to high glucose readily developed into lipid-loaded cells, as demonstrated by Oil Red O staining and cholesterol content analysis. In addition, high glucose-induced down-regulation of ABCG1 was reversed by nuclear factor-kappaB (NF-kappaB) inhibitors BAY 11-7085 and tosyl-phenylalanine chloromethyl ketone and by the antioxidant N-acetyl-L-cysteine (NAC). This reversal was accompanied by reduced cellular lipid content. Also, NAC and NF-kappaB inhibitors can effectively block the high glucose-induced activity of NF-kappaB binding to DNA and/or peroxide production.. These results suggested that hyperglycaemia-induced foam cell formation in VSMCs was related to the imbalanced lipid flux by increasing CD36-mediated modified low-density lipoprotein uptake and reducing ABCG1-regulated cellular cholesterol efflux. Moreover, this effect was associated with increased oxidative stress and activated NF-kappaB pathway signalling.

Topics: Antioxidants; Aorta; Apolipoprotein A-I; ATP Binding Cassette Transporter, Subfamily G, Member 1; ATP-Binding Cassette Transporters; CD36 Antigens; Cells, Cultured; Cholesterol; Cholesterol Esters; Cholesterol, HDL; Foam Cells; Glucose; Homeostasis; Humans; Hyperglycemia; Muscle, Smooth, Vascular; NF-kappa B; Nitriles; Peroxides; Signal Transduction; Sulfones; Tosylphenylalanyl Chloromethyl Ketone