TY - JOUR
T1 - Glycoxidized low-density lipoprotein downregulates endothelial nitric oxide synthase in human coronary cells
AU - Napoli, Claudio
AU - Lerman, Lilach O.
AU - De Nigris, Filomena
AU - Loscalzo, Joseph
AU - Ignarro, Louis J.
N1 - Funding Information:
This study was partially supported by the National Institutes of Health grants HL-58433 and HL-63282.
PY - 2002/10/16
Y1 - 2002/10/16
N2 - OBJECTIVES: We examined the hypothesis that low-density lipoprotein (LDL) that is both oxidized and glycosylated potently downregulates the expression of endothelial nitric oxide synthase III (NOSIII) in human coronary endothelial cells. BACKGROUND: Diabetes mellitus is accompanied by both oxidation and glycosylation of LDL, but the potential interaction of these processes or the pathophysiologic effects of these modified lipoproteins on arteries are poorly understood. METHODS: Low-density lipoprotein was glycoxidized in vitro, and Western and Northern blot analyses were used to investigate NOSIII expression in human coronary endothelial cells. Nitric oxide (NO) bioactivity was represented by both basal and bradykinin-stimulated cellular cyclic guanosine monophosphate accumulation and L-citrulline conversion from L-arginine. Nuclear run-on experiments were performed to study the transcription rate of nascent NOSIII messenger ribonucleic acid (mRNA). RESULTS: Data showed a significant decrease in NOSIII expression after 24-h treatment with glycosylated low-density lipoprotein (glycLDL) and oxidized low-density lipoprotein (ox-LDL). Accordingly, we observed a significant dose-dependent reduction in NO bioactivity (p < 0.05 to p < 0.001 vs. untreated cells, native low lipoprotein [nLDL], glycLDL, and oxLDL). Glyc-oxLDL did not reduce the half-life of NOSIII mRNA or significantly enhance L-citrulline conversion. Nuclear run-on experiments showed that high doses of glyc-oxLDL can reduce the transcription rate of nascent NOSIII mRNA (densitometric analysis revealed a reduction of 25% [p < 0.05 vs. untreated cells, nLDL, and glycLDL] after treatment of cells with 300 μg/ml glyc-oxLDL). The effects of glyc-oxLDL are not related to the higher levels of oxidative compounds in comparison to those of oxLDL. CONCLUSIONS: These results indicate that glyc-oxLDL, per se, may influence signal transduction pathways involving NO-mediated regulatory signals and NOSIII activity in human endothelial cells. This phenomenon can adversely influence the evolution of clinical vascular complications, coronary heart disease, and atherogenesis in diabetic patients.
AB - OBJECTIVES: We examined the hypothesis that low-density lipoprotein (LDL) that is both oxidized and glycosylated potently downregulates the expression of endothelial nitric oxide synthase III (NOSIII) in human coronary endothelial cells. BACKGROUND: Diabetes mellitus is accompanied by both oxidation and glycosylation of LDL, but the potential interaction of these processes or the pathophysiologic effects of these modified lipoproteins on arteries are poorly understood. METHODS: Low-density lipoprotein was glycoxidized in vitro, and Western and Northern blot analyses were used to investigate NOSIII expression in human coronary endothelial cells. Nitric oxide (NO) bioactivity was represented by both basal and bradykinin-stimulated cellular cyclic guanosine monophosphate accumulation and L-citrulline conversion from L-arginine. Nuclear run-on experiments were performed to study the transcription rate of nascent NOSIII messenger ribonucleic acid (mRNA). RESULTS: Data showed a significant decrease in NOSIII expression after 24-h treatment with glycosylated low-density lipoprotein (glycLDL) and oxidized low-density lipoprotein (ox-LDL). Accordingly, we observed a significant dose-dependent reduction in NO bioactivity (p < 0.05 to p < 0.001 vs. untreated cells, native low lipoprotein [nLDL], glycLDL, and oxLDL). Glyc-oxLDL did not reduce the half-life of NOSIII mRNA or significantly enhance L-citrulline conversion. Nuclear run-on experiments showed that high doses of glyc-oxLDL can reduce the transcription rate of nascent NOSIII mRNA (densitometric analysis revealed a reduction of 25% [p < 0.05 vs. untreated cells, nLDL, and glycLDL] after treatment of cells with 300 μg/ml glyc-oxLDL). The effects of glyc-oxLDL are not related to the higher levels of oxidative compounds in comparison to those of oxLDL. CONCLUSIONS: These results indicate that glyc-oxLDL, per se, may influence signal transduction pathways involving NO-mediated regulatory signals and NOSIII activity in human endothelial cells. This phenomenon can adversely influence the evolution of clinical vascular complications, coronary heart disease, and atherogenesis in diabetic patients.
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U2 - 10.1016/S0735-1097(02)02306-9
DO - 10.1016/S0735-1097(02)02306-9
M3 - Article
C2 - 12392844
AN - SCOPUS:0037120943
SN - 0735-1097
VL - 40
SP - 1515
EP - 1522
JO - Journal of the American College of Cardiology
JF - Journal of the American College of Cardiology
IS - 8
ER -