Reverse cholesterol transport (RCT) - transfer of macrophage-cholesterol in the subendothelial space of the arterial wall to the liver - is terminated by selective high density lipoprotein (HDL)-cholesteryl ester (CE) uptake, mediated by scavenger receptor class B, type 1 (SR-B1). We tested the validity of two models for this process - gobbling, i.e., one-step transfer of all HDL-CE to the cell and nibbling, multiple successive cycles of SR-B1-HDL association during which a few CE transfer to the cell. Concurrently, we compared cellular uptake of apo AI with that of apo AII, which is more lipophilic than apo AI, using HDL-[3H]CE labeled with [125I]apo AI or [125I]apo AII. The studies were conducted in CHO-K1 and CHO-ldlA7 cells (LDLR-/-) with (CHO-SR-B1) and without SR-B1 over expression, and in human Huh7 hepatocytes. Relative to CE, both apo AI and apo AII were excluded from uptake by all cells. However, apo AII was more highly excluded from uptake (2-4x) than apo AI. To distinguish gobbling vs. nibbling mechanisms, media from incubations of HDL with CHO-SR-B1 cells were analyzed by non-denaturing PAGE, size exclusion chromatography, and the distribution of apo AI, apo AII, cholesterol and phospholipid among HDL species as a function of incubation time. HDL size gradually decreased, i.e., nibbling, with the concurrent release of lipid-free apo AI; apo AII was retained in an HDL remnant. Our data support a SR-B1 nibbling mechanism that is similar to that of streptococcal serum opacity factor, which also selectively removes CE and releases apo AI leaving an apo AII-rich remnant.
from #AlexandrosSfakianakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/2nRgMTD
via IFTTT
Εγγραφή σε:
Σχόλια ανάρτησης (Atom)
Δημοφιλείς αναρτήσεις
-
Publication date: Available online 4 January 2018 Source: European Journal of Radiology Author(s): Peiyao Zhang, Jing Wang, Qin Xu, Zhen...
-
Related Articles Anatomic parameters of the sacral lamina for osteosynthesis in transverse sacral fractures. Surg Radiol Anat....
-
Background Hyperthyroidism is associated with increased thrombotic risk. As contact system activation through formation of neutrophil extrac...
-
BACKGROUND AND PURPOSE: Dengue is a common arboviral disease, which uncommonly involves the brain. There has been a recent surge in dengu...
-
Abstract Purpose Investigate in patients with metastatic and/or irresectable colorectal cancer treated with systemic treatment with cape...
-
Publication date: January 2017 Source: The Journal of Emergency Medicine, Volume 52, Issue 1 Author(s): Patricia Michelle Troxell Klingen...
-
In rural Kenya, traditional and faith healers provide an alternative pathway to health care, including mental health care. However, not much...
-
2016-12-10T02-17-59Z Source: Indo American Journal of Pharmaceutical Research R. Santosh Kumar*, T. Naga Satya Yagnesh. Solid dispersio...
-
Medicine by Alexandros G. Sfakianakis,Anapafseos 5... Medicine by Alexandros G. Sfakianakis,Anapafseos 5... Heralding change: The evolution ...
Δεν υπάρχουν σχόλια:
Δημοσίευση σχολίου