Binding to heparin triggers deleterious structural and biochemical changes in human low-density lipoprotein, which are amplified in hyperglycemia
Por:
Jayaraman, S, Chavez, OR, Perez, A, Minambres, I, Sanchez-Quesada, JL, Gursky, O
Publicada:
1 ago 2020
Resumen:
Low-density lipoprotein (LDL) binding to arterial proteoglycans initiates LDL retention and modification in the arterial wall, triggering atherosclerosis. The details of this binding, its effectors, and its ramifications are incompletely understood. We combined heparin affinity chromatography with biochemical, spectroscopic and electron microscopic techniques to show that brief binding to heparin initiates irreversible pro-atherogenic remodeling of human LDL. This involved decreased structural stability of LDL and increased susceptibility to hydrolysis, oxidation and fusion. Furthermore, phospholipid hydrolysis, mild oxidation and/or glycation of LDL in vitro increase the proteolytic susceptibility of apoB and its heparin binding affinity, perhaps by unmasking additional heparin-binding sites. For LDL from hyperglycemic type-2 diabetic patients, heparin binding was particularly destabilizing and caused apoB fragmentation and LDL fusion. However, for similar patients whose glycemic control was restored upon therapy, LDL-heparin binding affinity was rectified and LDL structural stability was partially restored. These results complement previous studies of LDL binding to arterial proteoglycans and suggest that such interactions may produce a particularly pro-atherogenic subclass of electronegative LDL. In summary, binding to heparin alters apoB conformation, perhaps by partially peeling it off the lipid, and triggers pro-atherogenic LDL modifications including hydrolysis, oxidation, and destabilization. Furthermore, phospholipid lipolysis, mild oxidation and glycation of LDL in vitro strengthen its binding to heparin, which helps explain stronger binding observed in hyperglycemic LDL. Combined effects of hyperglycemia and heparin binding are especially deleterious but are largely rectified upon diabetes therapy. These findings help establish a mechanistic link between diabetes and atherosclerosis.
Filiaciones:
Jayaraman, S:
Boston Univ, Dept Physiol & Biophys, Sch Med, W321,700 Albany St, Boston, MA 02118 USA
Chavez, OR:
Boston Univ, Dept Physiol & Biophys, Sch Med, W321,700 Albany St, Boston, MA 02118 USA
Perez, A:
Hosp Santa Creu & Sant Pau, Endocrinol Dept, Barcelona, Spain
CIBER Diabet & Metab Dis CIBERDEM, Madrid, Spain
Minambres, I:
Hosp Santa Creu & Sant Pau, Endocrinol Dept, Barcelona, Spain
Sanchez-Quesada, JL:
CIBER Diabet & Metab Dis CIBERDEM, Madrid, Spain
Hosp Santa Creu & Sant Pau, CIBERDEM, Cardiovasc Biochem Grp, Res Inst, Barcelona, Spain
Gursky, O:
Boston Univ, Dept Physiol & Biophys, Sch Med, W321,700 Albany St, Boston, MA 02118 USA
Boston Univ, Sch Med, Amyloidosis Treatment & Res Ctr, Boston, MA 02118 USA
Green Accepted
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