Glycoxidized low-density lipoprotein downregulates endothelial nitric oxide synthase in human coronary cells

Claudio Napoli, Lilach O Lerman, Filomena De Nigris, Joseph Loscalzo, Louis J. Ignarro

Research output: Contribution to journalArticle

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Abstract

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.

Original languageEnglish (US)
Pages (from-to)1515-1522
Number of pages8
JournalJournal of the American College of Cardiology
Volume40
Issue number8
DOIs
StatePublished - Oct 16 2002
Externally publishedYes

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Nitric Oxide Synthase Type III
LDL Lipoproteins
Down-Regulation
Nitric Oxide Synthase
Citrulline
Nitric Oxide
Endothelial Cells
RNA
Lipoproteins
oxidized low density lipoprotein
Cyclic GMP
Bradykinin
Glycosylation
Human Activities
Northern Blotting
Coronary Disease
Blood Vessels
Half-Life
Arginine
Signal Transduction

ASJC Scopus subject areas

  • Nursing(all)

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Glycoxidized low-density lipoprotein downregulates endothelial nitric oxide synthase in human coronary cells. / Napoli, Claudio; Lerman, Lilach O; De Nigris, Filomena; Loscalzo, Joseph; Ignarro, Louis J.

In: Journal of the American College of Cardiology, Vol. 40, No. 8, 16.10.2002, p. 1515-1522.

Research output: Contribution to journalArticle

Napoli, Claudio ; Lerman, Lilach O ; De Nigris, Filomena ; Loscalzo, Joseph ; Ignarro, Louis J. / Glycoxidized low-density lipoprotein downregulates endothelial nitric oxide synthase in human coronary cells. In: Journal of the American College of Cardiology. 2002 ; Vol. 40, No. 8. pp. 1515-1522.
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abstract = "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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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.

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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