Size and Dynamics of Caveolae Studied Using Nanoparticles in Living Endothelial Cells

Abstract

Caveolae are plasma membrane invaginations prominent in all endothelial cells lining blood vessels. Caveolae characteristically bud to form free cytoplasmic vesicles capable of transporting carrier proteins such as albumin through the cell. However, caveolae size distribution and dynamics in living endothelial cells and ability of caveolae to internalize nanoparticles are not well understood. We demonstrate here the design of a dual-color nanoparticle pair to measure non-invasively caveolae size and dynamics. First, we coated nanoparticles with BSA (bovine serum albumin) to address whether albumin promoted their delivery. Albumin has been shown to bind to protein on endothelial cell surface localized in caveolae and activate albumin endocytosis. Imaging of BSA-coated nanoparticles varying from 20-100nm in diameter in endothelial cells, demonstrated that caveolae-mediated nanoparticle uptake was dependent on albumin coating of particles. We also showed that caveolae could accommodate up to 100nm diameter nanoparticles, a size larger than the diameter of typical caveolae, suggesting compliant property of caveolae. Together, our results show the feasibility of tracking multi-colored nanoparticles in living endothelial cells and potential usefulness for designing therapeutic nanoparticle cargo to cross the limiting vessel wall endothelial barrier.

Interaction of hydroxyapatite nanoparticles with endothelial cells: internalization and inhibition of angiogenesis in vitro through the PI3K/Akt pathway

“…It is well accepted that several endocytic pathways, such as clathrin-and caveolin-mediated endocytosis as well as macropinocytosis, are involved in the 45 Recent investigations have suggested that caveolae-mediated endocytosis is an important pathway that transports gold NPs and polystyrene NPs into ECs. [46][47][48] In this study, the results showed that HAPs were less uptaken in the presence of cpz, mβcd and cytoD, but to a different degree ( Figure 6). For np20 and np80, mβcd had the most obvious inhibitory effects, followed by cytoD, implying clathrin-and caveolin-mediated endocytosis as the crucial internalization pathways that HANPs enter HUVECs, and actin-dependent macropinocytosis also played an important role in the process.…”

Dendrimer-RNA nanoparticles generate protective immunity against lethal Ebola, H1N1 influenza, and Toxoplasma gondii challenges with a single dose

“…RNA, particularly single-stranded RNA, is rapidly degraded by nucleases when injected in vivo (37). Although therapeutic RNA can be chemically modified to facilitate delivery and reduce immunogenicity (38)(39)(40)(41), no such modifications have been reported for replicons; this may reflect the sensitivity of the viral replicase to base modification (42)(43)(44) or to the secondary structure effects modifications may have on vital conserved RNA replication elements (45). We reasoned that nanoformulation could allow for the protection and functional delivery of replicon mRNA vaccines.…”

Multifactorial determinants that govern nanoparticle uptake by human endothelial cells under flow

“…However, previous studies performed with BSA-coated polymeric NPs on ECs have demonstrated that caveolae could accommodate particles of up to 100 nm; this is larger than the typical caveolar diameter, which suggests that these organelles have adaptable properties. 47 The cytoskeletal and topographic changes of untreated HUVECs in response to SS were analyzed by confocal microscopy and AFM. In our studies, membrane ruffling and the endocytosis of CdTe-QDs were detected exclusively in cells that had been exposed to SS.…”