title: Crosstalk Between Glycoxidative Modification of Low-Density Lipoprotein, Angiotensin II-Sensitization, and Adrenocortical Aldosterone Release.
abstract: Low-density lipoprotein (LDL) is considered to be a risk factor for atherosclerosis. In the presence of hyperglycemia, LDL undergoes glycoxidative modification and this glycoxidized (glycox) LDL promotes atherosclerosis in type 2 diabetic (T2D) individuals. Moreover, because of its cholesterol content, LDL contributes to aldosterone biosynthesis, which is modulated by angiotensin II (AngII) and has been implicated in cardiovascular complications of T2D. However, the molecular mechanism of the crosstalk between glycoxLDL, AngII, and aldosterone has not been explained clearly. Therefore, this study has been aimed to investigate the impact of in vitro modified glycoxLDL on aldosterone release in an AngII-sensitized adrenocortical carcinoma cell line (NCI H295R). Native LDL (natLDL), isolated from healthy volunteers by sequential density gradient ultracentrifugation, was subjected to d-glucose (200 mmol/l), for glycoxidative modification, at 37 °C for 6 days. The AngII-sensitized H295R cells were treated with natLDL and glycoxLDL for 24 h and the supernatant was used for aldosterone measurement. The treated cells were utilized for protein isolation and mRNA quantification. Compared to natLDL, glycoxLDL produced a significantly greater effect on aldosterone release from AngII-sensitized cells. The treatment with specific pharmacological inhibitors suggests that modified LDL recruits ERK1/2 and janus kinase-2 for transcriptional regulation of aldosterone synthase. Moreover, glycoxLDL modulates aldosterone release via cAMP-dependent protein kinase A (PKA) pathway. However, glycoxLDL induces ERK phosphorylation independent of PKA activation and this novel mechanism could be targeted for therapeutic trials. In conclusion, this in vitro study emphasizes a possible causal relationship between LDL glycoxidative modification, AngII-sensitization, and adrenocortical steroid hormone release.
authors.affiliation: Department of Internal Medicine 3, Carl Gustav Carus Medical School,Technische Universität Dresden, Dresden, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Saha
authors.affiliation: Department of Internal Medicine 3, Carl Gustav Carus Medical School,Technische Universität Dresden, Dresden, Germany.
authors.forename: S R
authors.initials: SR
authors.lastname: Bornstein
authors.affiliation: Department of Internal Medicine 3, Carl Gustav Carus Medical School,Technische Universität Dresden, Dresden, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Graessler
authors.affiliation: Department of Internal Medicine 3, Carl Gustav Carus Medical School,Technische Universität Dresden, Dresden, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Kopprasch
mesh_terms: D000302:Adrenal Cortex / Q000187:drug effects / Q000378:metabolism*; D000450:Aldosterone / Q000378:metabolism*; D000804:Angiotensin II / Q000494:pharmacology*; D002460:Cell Line; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D019405:Cytochrome P-450 CYP11B2 / Q000235:genetics; D004789:Enzyme Activation / Q000187:drug effects; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006031:Glycosylation / Q000187:drug effects; D006801:Humans; D053614:Janus Kinase 2 / Q000378:metabolism; D008077:Lipoproteins, LDL / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000187:drug effects; D010766:Phosphorylation / Q000187:drug effects; D013256:Steroids / Q000096:biosynthesis; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D008077:Lipoproteins, LDL; D013256:Steroids; D000804:Angiotensin II; D000450:Aldosterone; D019405:Cytochrome P-450 CYP11B2; C507924:JAK2 protein, human; D053614:Janus Kinase 2; D017868:Cyclic AMP-Dependent Protein Kinases; D048049:Extracellular Signal-Regulated MAP Kinases