scholarly journals CD36 N-terminal cytoplasmic domain is not required for the internalization of oxidized low-density lipoprotein

2008 ◽  
Vol 28 (3) ◽  
pp. 145-151 ◽  
Author(s):  
Chris McDermott-Roe ◽  
Juliette Martin ◽  
Sophie Collot-Teixeira ◽  
John L. McGregor

The uptake of OxLDLs (oxidized low density lipoproteins) by CD36-expressing macrophages in the arterial intima and the subsequent ‘foam cell’ formation represents a crucial step in the initiation and development of atherosclerotic plaques. The present study has addressed the function of the CD36 N-terminal cytoplasmic domain in the binding and internalization of OxLDL. A selection of CD36 N-terminal cytoplasmic domain mutants were generated and stably expressed in HEK-293 (human embryonic kidney) cells. The capacity of three mutants [CD36_C3/7-A (CD36-C3A/C7A), CD36_D4/R5-A (CD36-D4A/R5A) and CD36_nCPD− (CD36 lacking the N-terminal cytoplasmic domain)] to bind and endocytose OxLDL was then studied using immunofluorescence microscopy and quantitative fluorimetry. Each of the CD36 constructs was expressed at differing levels at the cell surface, as measured by flow cytometry and Western blotting. Following incubation with DiI (1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate)–OxLDL, cells bearing the CD36_wt (wild-type CD36), CD36_C3/7-A, CD36_D4/R5-A and CD36_nCPD− constructs all internalized DiI–OxLDL into endosomal structures, whereas empty-vector-transfected cells failed to do so, indicating that, unlike the C-terminal cytoplasmic domain, the N-terminal cytoplasmic domain is not essential for the endocytosis of OxLDL. In conclusion, the uptake of OxLDL by CD36 is not reliant on the presence of the CD36 N-terminal cytoplasmic domain. However, the N-terminal cytoplasmic domain may conceivably be implicated in the maturation of CD36.

2021 ◽  
Vol 14 (6) ◽  
pp. 567
Author(s):  
Su Wutyi Thant ◽  
Noppawan Phumala Morales ◽  
Visarut Buranasudja ◽  
Boonchoo Sritularak ◽  
Rataya Luechapudiporn

Oxidation of low-density lipoprotein (LDL) plays a crucial role in the pathogenesis of atherosclerosis. Hemin (iron (III)-protoporphyrin IX) is a degradation product of hemoglobin that can be found in thalassemia patients. Hemin is a strong oxidant that can cause LDL oxidation and contributes to atherosclerosis in thalassemia patients. Lusianthridin from Dendrobium venustrum is a phenolic compound that possesses antioxidant activity. Hence, lusianthridin could be a promising compound to be used against hemin-induced oxidative stress. The major goal of this study is to evaluate the protective effect of lusianthridin on hemin-induced low-density lipoprotein oxidation (he-oxLDL). Here, various concentrations of lusianthridin (0.25, 0.5, 1, and 2 µM) were preincubated with LDL for 30 min, then 5 µM of hemin was added to initiate the oxidation, and oxidative parameters were measured at various times of incubation (0, 1, 3, 6, 12, 24 h). Lipid peroxidation of LDL was measured by thiobarbituric reactive substance (TBARs) assay and relative electrophoretic mobility (REM). The lipid composition of LDL was analyzed by using reverse-phase HPLC. Foam cell formation with he-oxLDL in RAW 264.7 macrophage cells was detected by Oil Red O staining. The results indicated that lusianthridin could inhibit TBARs formation, decrease REM, decrease oxidized lipid products, as well as preserve the level of cholesteryl arachidonate and cholesteryl linoleate. Moreover, He-oxLDL incubated with lusianthridin for 24 h can reduce the foam cell formation in RAW 264.7 macrophage cells. Taken together, lusianthridin could be a potential agent to be used to prevent atherosclerosis in thalassemia patients.


1988 ◽  
Vol 16 (6) ◽  
pp. 877-879
Author(s):  
Kenji ISHII ◽  
Toru KITA ◽  
Yutaka NAGANO ◽  
Noriaki KUME ◽  
Masayuki YOKODE ◽  
...  

2020 ◽  
Vol 21 (21) ◽  
pp. 8312
Author(s):  
Takashi Obama ◽  
Hiroyuki Itabe

Neutrophil extracellular traps (NETs) significantly contribute to various pathophysiological conditions, including cardiovascular diseases. NET formation in the vasculature exhibits inflammatory and thrombogenic activities on the endothelium. NETs are induced by various stimulants such as exogenous damage-associated molecular patterns (DAMPs). Oxidatively modified low-density lipoprotein (oxLDL) has been physiologically defined as a subpopulation of LDL that comprises various oxidative modifications in the protein components and oxidized lipids, which could act as DAMPs. oxLDL has been recognized as a crucial initiator and accelerator of atherosclerosis through foam cell formation by macrophages; however, recent studies have demonstrated that oxLDL stimulates neutrophils to induce NET formation and enhance NET-mediated inflammatory responses in vascular endothelial cells, thereby suggesting that oxLDL may be involved in cardiovascular diseases through neutrophil activation. As NETs comprise myeloperoxidase and proteases, they have the potential to mediate oxidative modification of LDL. This review summarizes recent updates on the analysis of NETs, their implications for cardiovascular diseases, and prospects for a possible link between NET formation and oxidative modification of lipoproteins.


2013 ◽  
Vol 227 (1) ◽  
pp. 51-57 ◽  
Author(s):  
Kenta Watanabe ◽  
Yuki Nakazato ◽  
Ryotaro Saiki ◽  
Kazuei Igarashi ◽  
Mitsukazu Kitada ◽  
...  

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