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Lipoprotein binding preference of CD36 is altered by filipin treatment.

Zhang J, Chu W, Crandall I - Lipids Health Dis (2008)

Bottom Line: Filipin treatment rapidly increased the binding capacity of CD36 for the native lipoproteins HDL and LDL, but did not affect the binding capacity of CD36 for oxidized LDL.Filipin treatment affected the distribution of caveolin and CD36 suggesting that the presence caveolae may modulate the ligand preference of CD36.However, its molecular mechanism how CD36 and caveolin interaction in regulating lipoprotein transport remains to be further studied.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Bioengineering and Environmental Science, Changsha University, Changsha, Hunan, PR China. jzhang@ccsu.cn

ABSTRACT
The class B scavenger receptor CD36 binds multiple ligands, including oxidized and native lipoprotein species. CD36 and the related receptor SR-B1 have been localized to caveolae, domains that participate in cell signaling, transcytosis, and regulation of cellular cholesterol homeostasis. Previous work has indicated that the ligand preference of CD36 may depend on the cell type in which it is expressed. To determine if the presence or absence of caveolae is the determining factor for lipoprotein preference, we treated CHO-CD36 and C32 cells with filipin. Filipin treatment rapidly increased the binding capacity of CD36 for the native lipoproteins HDL and LDL, but did not affect the binding capacity of CD36 for oxidized LDL. Filipin treatment affected the distribution of caveolin and CD36 suggesting that the presence caveolae may modulate the ligand preference of CD36. However, its molecular mechanism how CD36 and caveolin interaction in regulating lipoprotein transport remains to be further studied.

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Effects of filipin on CD36 surface protein expression in CHO-CD36 cells. CHO-CD36 cells were treated with filipin at 10 μg/ml and assayed for CD36 protein expression by immuostaining with FITC-conjugated anti-CD36 antibody (Left panel, no filipin treated; middle panel, filipin treated showing higher fluoreence indensity) and flow cytometry (right panel, dark traces treated with filipin and gray traces without filipin treatment as control).
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Figure 4: Effects of filipin on CD36 surface protein expression in CHO-CD36 cells. CHO-CD36 cells were treated with filipin at 10 μg/ml and assayed for CD36 protein expression by immuostaining with FITC-conjugated anti-CD36 antibody (Left panel, no filipin treated; middle panel, filipin treated showing higher fluoreence indensity) and flow cytometry (right panel, dark traces treated with filipin and gray traces without filipin treatment as control).

Mentions: CD36 has palmitoylated cysteine residues in its transmembrane regions which is consistent with its localization to caveolae [40-42]. Numerous receptors are known to change their behavior when they become associated with caveolae [29,43,44], therefore we examined the effect of the caveolae disrupting agent filipin [45] on the interaction between CHO-CD36 cells and DiI-lipoproteins. Untreated CHO-CD36 cells bound only oxLDL (Fig. 1), however when CHO-CD36 cells were exposed to filipin at 10 μg/ml for 30 min, they bound all three Dil-lipoproteins (Fig. 3A). Compared to untreated samples, filipin increased CHO-CD36 cell-associated Dil-HDL and Dil-LDL by 160% and 120% respectively, however no significant change was detected for DiI-oxLDL binding to CHO-CD36 cells (Fig. 3B). C32 cells, which natively express CD36, were treated in the same manner and results similar to those seen in CHO-CD36 cells were obtained (results not shown). Caveolae are surface invaginations or clefts [46]. To determine if the observed binding changes were accompanied by an increase or decrease in surface accessible CD36, we evaluated CD36 surface expression by flow cytometery using an anti-CD36-FITC conjugated antibody. Upon treatment with filipin CD36 detectable on the surface was significant increased in CHO-CD36 (Fig. 4).


Lipoprotein binding preference of CD36 is altered by filipin treatment.

Zhang J, Chu W, Crandall I - Lipids Health Dis (2008)

Effects of filipin on CD36 surface protein expression in CHO-CD36 cells. CHO-CD36 cells were treated with filipin at 10 μg/ml and assayed for CD36 protein expression by immuostaining with FITC-conjugated anti-CD36 antibody (Left panel, no filipin treated; middle panel, filipin treated showing higher fluoreence indensity) and flow cytometry (right panel, dark traces treated with filipin and gray traces without filipin treatment as control).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2483703&req=5

Figure 4: Effects of filipin on CD36 surface protein expression in CHO-CD36 cells. CHO-CD36 cells were treated with filipin at 10 μg/ml and assayed for CD36 protein expression by immuostaining with FITC-conjugated anti-CD36 antibody (Left panel, no filipin treated; middle panel, filipin treated showing higher fluoreence indensity) and flow cytometry (right panel, dark traces treated with filipin and gray traces without filipin treatment as control).
Mentions: CD36 has palmitoylated cysteine residues in its transmembrane regions which is consistent with its localization to caveolae [40-42]. Numerous receptors are known to change their behavior when they become associated with caveolae [29,43,44], therefore we examined the effect of the caveolae disrupting agent filipin [45] on the interaction between CHO-CD36 cells and DiI-lipoproteins. Untreated CHO-CD36 cells bound only oxLDL (Fig. 1), however when CHO-CD36 cells were exposed to filipin at 10 μg/ml for 30 min, they bound all three Dil-lipoproteins (Fig. 3A). Compared to untreated samples, filipin increased CHO-CD36 cell-associated Dil-HDL and Dil-LDL by 160% and 120% respectively, however no significant change was detected for DiI-oxLDL binding to CHO-CD36 cells (Fig. 3B). C32 cells, which natively express CD36, were treated in the same manner and results similar to those seen in CHO-CD36 cells were obtained (results not shown). Caveolae are surface invaginations or clefts [46]. To determine if the observed binding changes were accompanied by an increase or decrease in surface accessible CD36, we evaluated CD36 surface expression by flow cytometery using an anti-CD36-FITC conjugated antibody. Upon treatment with filipin CD36 detectable on the surface was significant increased in CHO-CD36 (Fig. 4).

Bottom Line: Filipin treatment rapidly increased the binding capacity of CD36 for the native lipoproteins HDL and LDL, but did not affect the binding capacity of CD36 for oxidized LDL.Filipin treatment affected the distribution of caveolin and CD36 suggesting that the presence caveolae may modulate the ligand preference of CD36.However, its molecular mechanism how CD36 and caveolin interaction in regulating lipoprotein transport remains to be further studied.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Bioengineering and Environmental Science, Changsha University, Changsha, Hunan, PR China. jzhang@ccsu.cn

ABSTRACT
The class B scavenger receptor CD36 binds multiple ligands, including oxidized and native lipoprotein species. CD36 and the related receptor SR-B1 have been localized to caveolae, domains that participate in cell signaling, transcytosis, and regulation of cellular cholesterol homeostasis. Previous work has indicated that the ligand preference of CD36 may depend on the cell type in which it is expressed. To determine if the presence or absence of caveolae is the determining factor for lipoprotein preference, we treated CHO-CD36 and C32 cells with filipin. Filipin treatment rapidly increased the binding capacity of CD36 for the native lipoproteins HDL and LDL, but did not affect the binding capacity of CD36 for oxidized LDL. Filipin treatment affected the distribution of caveolin and CD36 suggesting that the presence caveolae may modulate the ligand preference of CD36. However, its molecular mechanism how CD36 and caveolin interaction in regulating lipoprotein transport remains to be further studied.

Show MeSH
Related in: MedlinePlus