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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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Comparison of lipoprotein binding to CD36 expressed in three cell lines. Sf9-CD36, Sf9, CHO-CD36, CHO-mock and C32 cells were grown on glass coverslips and incubated with Dil-labeled lipoproteins (as indicated) at 10 ug/ml of lipoprotein in culture medium at 37°C for 2 – 4 hours. Dil-labeled lipoproteins was determined by examining the cell layers using a fluorescence microscope. Typical images were recorded.
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Figure 1: Comparison of lipoprotein binding to CD36 expressed in three cell lines. Sf9-CD36, Sf9, CHO-CD36, CHO-mock and C32 cells were grown on glass coverslips and incubated with Dil-labeled lipoproteins (as indicated) at 10 ug/ml of lipoprotein in culture medium at 37°C for 2 – 4 hours. Dil-labeled lipoproteins was determined by examining the cell layers using a fluorescence microscope. Typical images were recorded.

Mentions: Previous reports have indicated that CD36 expressed in Sf 9 and COS 7 cells [24] interacts with OxLDL, LDL and HDL, while CD36 expressed in CHO cells does not [35]. To determine if cell type specific lipoprotein binding was present in different cell lines, Sf9-CD36, CHO-CD36 and C32 were incubated with DiI labeled lipoprotein (1,1'diotadecyl3-3'-3'-tetramethylindocarbo-cyanine perchlorate (Dil) [36] prior to examination by fluorescence microscopy. Sf9 cells infected with baculovirus containing the gene for human CD36 displayed an intense staining with each of the three lipoproteins (Fig. 1, Sf9-CD36), as has been previously reported [24,33]. Whereas mock-transfected Sf9 cells did not bind DiI-labeled lipoproteins (Fig. 1, Sf9). CHO cells that expressed the CD36 gene bound DiI-oxLDL but not Dil-HDL or Dil-LDL. (Fig. 1, CHO-CD36). CHO-mock cells did not interact with any of the lipoproteins (Fig. 1, CHO-mock). These ligand preferences were consistent with our previous observations, however we wished to extend these observations to human cells. We therefore repeated our experiments using C32 amelanotic melanoma cells, which endogenously express human CD36 [37-39]. The ligand preferences of C32 cells were found to be similar to CHO-CD36 cells (Fig. 1, C32). The interaction was specific to CD36 since receptor blockade with an anti-CD36 antibody (Fig. 2A) and competition with unlabeled oxLDL (Fig. 2C) inhibited the interaction of labeled oxLDL with CHO-CD36 cells.


Lipoprotein binding preference of CD36 is altered by filipin treatment.

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

Comparison of lipoprotein binding to CD36 expressed in three cell lines. Sf9-CD36, Sf9, CHO-CD36, CHO-mock and C32 cells were grown on glass coverslips and incubated with Dil-labeled lipoproteins (as indicated) at 10 ug/ml of lipoprotein in culture medium at 37°C for 2 – 4 hours. Dil-labeled lipoproteins was determined by examining the cell layers using a fluorescence microscope. Typical images were recorded.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 1: Comparison of lipoprotein binding to CD36 expressed in three cell lines. Sf9-CD36, Sf9, CHO-CD36, CHO-mock and C32 cells were grown on glass coverslips and incubated with Dil-labeled lipoproteins (as indicated) at 10 ug/ml of lipoprotein in culture medium at 37°C for 2 – 4 hours. Dil-labeled lipoproteins was determined by examining the cell layers using a fluorescence microscope. Typical images were recorded.
Mentions: Previous reports have indicated that CD36 expressed in Sf 9 and COS 7 cells [24] interacts with OxLDL, LDL and HDL, while CD36 expressed in CHO cells does not [35]. To determine if cell type specific lipoprotein binding was present in different cell lines, Sf9-CD36, CHO-CD36 and C32 were incubated with DiI labeled lipoprotein (1,1'diotadecyl3-3'-3'-tetramethylindocarbo-cyanine perchlorate (Dil) [36] prior to examination by fluorescence microscopy. Sf9 cells infected with baculovirus containing the gene for human CD36 displayed an intense staining with each of the three lipoproteins (Fig. 1, Sf9-CD36), as has been previously reported [24,33]. Whereas mock-transfected Sf9 cells did not bind DiI-labeled lipoproteins (Fig. 1, Sf9). CHO cells that expressed the CD36 gene bound DiI-oxLDL but not Dil-HDL or Dil-LDL. (Fig. 1, CHO-CD36). CHO-mock cells did not interact with any of the lipoproteins (Fig. 1, CHO-mock). These ligand preferences were consistent with our previous observations, however we wished to extend these observations to human cells. We therefore repeated our experiments using C32 amelanotic melanoma cells, which endogenously express human CD36 [37-39]. The ligand preferences of C32 cells were found to be similar to CHO-CD36 cells (Fig. 1, C32). The interaction was specific to CD36 since receptor blockade with an anti-CD36 antibody (Fig. 2A) and competition with unlabeled oxLDL (Fig. 2C) inhibited the interaction of labeled oxLDL with CHO-CD36 cells.

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