Lectin-like oxidized LDL receptor-1 is palmitoylated and internalizes ligands via caveolae/raft-dependent endocytosis.

Lectin-like oxidized low-density lipoprotein (LDL) receptor-1 (LOX-1) is an endothelial scavenger receptor that is important for oxidized low-density lipoprotein uptake. LOX-1 functions as an oligomer; however, little is known about the oligomeric complex and ligand processing after recognition by LOX-1. Here, we found that LOX-1 recognized and internalized ligands through the caveolae/raft-dependent endocytosis pathway in human coronary artery endothelial cells. Furthermore, we demonstrated that LOX-1 was palmitoylated and that both cysteine 36 and cysteine 46 were necessary for the recruitment of LOX-1 into raft microdomains and for its ligand uptake ability.

Contribution of physicochemical characteristics of nano-oxides to cytotoxicity.

To identify the key physicochemical properties of nano-oxides governing cytotoxicity, we investigate the contribution of the size, shape, morphology, and electronic properties of ten types of insulator (SiO(2), CeO(2) and Al(2)O(3)) and semiconductor (ZnO and CuO) nano-oxides to cytotoxicity using the NIH3T3 and A549 cell lines as models. We find that the shape of the Al(2)O(3) (nanoparticle versus nanowhisker) and the morphology of the SiO(2) (porous versus non-porous nanoparticles) did not have obvious effect on the observed cytotoxicity, and the size of the nano-oxides cannot be regarded as an indicator of cytotoxicity. By contrast, we find that the cell viability exposed to the semiconductor nano-oxides was much lower than that exposed to the insulator nano-oxides. Moreover, the Al-doped ZnO nanoparticle (NP) was more toxic than the non-doped ZnO NP, whereas the Al-doped CuO NP was less toxic than the non-doped CuO NP but more toxic than the Al(2)O(3) NP. Correspondingly, the valence band X-ray photoelectron spectra of the nano-oxides show the density of states of the Al-doped ZnO NP (the Al-doped CuO NP) is higher (lower) than that of the non-doped ZnO NP (the non-doped CuO NP). These results suggest that the electronic properties of nano-oxides may play an important role in the observed cytotoxicity. The results have implications for selectively tailoring the toxic effect and establishing predictive models for the design of various types of nanomaterials with unique properties and for the understanding of interactions between nanomaterials with biological system.