Translocation of Poly(ethylene glycol-co-hexadecyl)cyanoacrylate Nanoparticles into Rat Brain Endothelial Cells:  Role of Apolipoproteins in Receptor-Mediated Endocytosis

Abstract

Previous in vivo observations in rats have shown that poly(ethylene glycol) polyhexadecylcyanoacrylate (PEG-PHDCA) nanoparticles could translocate into the brain after intravenous injection, which polyhexadecylcyanoacrylate (PHDCA) nanoparticles did not. Through the detailed analysis of the plasma protein adsorption onto the surface of PEG-PHDCA nanoparticles, the present study aimed at clarifying the mechanism by which nanoparticles could penetrate into rat brain endothelial cells (RBEC). Two-dimensional polyacrylamide gel electrophoresis and Western blotting revealed that, after incubation with rat serum, apolipoprotein E (ApoE) adsorbed more onto PEG-PHDCA than on PHDCA nanoparticles. Adsorption of apolipoprotein B-100 (ApoB-100) onto PEG-PHDCA nanoparticles was demonstrated by capillary electrophoresis experiments. Moreover, only when ApoE or ApoB-100 were preadsorbed onto PEG-PHDCA nanoparticles, nanoparticles were found to be more efficient than control nanoparticles for penetrating into RBEC, suggesting the involvement of a low density lipoprotein receptor in this process. Thus, these data clearly demonstrate the involvement of apolipoproteins in the brain transport of PEG-PHDCA nanoparticles, which may open interesting prospects for brain drug delivery.

‘Stealth’ nanoparticles evade neural immune cells but also evade major brain cell populations: Implications for PEG-based neurotherapeutics

“…In particular, polyethylene glycol (PEG) is a widely used polymer used to impart stealth properties. PEGylated materials evade the MPS, enhancing bioavailability, and possess the ability to cross the BBB, for which the exact mechanism is unknown but could include transcytosis or receptor-mediated endocytosis [15]. PEG-coated nanoparticles accumulate in brain tissue more effectively than non-PEG-coated nanoparticles, and those coated with high density PEG also display greater diffusion through brain parenchyma [4,16].…”

Targeting low-density lipoprotein receptors with protein-only nanoparticles

“…Although these and other properties of nanostructured materials are highly desirable, paracelullar penetration of nanoparticles targeted to the central nervous system (CNS) is assumed to be especially problematical. Functionalization with ligands of hormone 80 receptors or transporters for transcytosis is then mandatory despite the unexpected BBB-crossing activities exhibited by a few polymers used for nanoparticle fabrication and coating (eg polysorbate 80 and poly-[ethylene glycol-co-hexadecyl]-cyanoacrylate (Kim et al, 2007;Kreuter et al, 2002a)). …”

“…In a step further, and particularly encouraged by the good performance of ApoB-GFPH6IBs nanoparticles we wanted to examine the biodistribution of the protein set and the potential influence of the supramolecular protein organization, upon systemic administration through the tail vein in healthy mice in which side events that affect brain 325 permeability such as enhanced permeability and retention (EPR) effect do not take place. We were specifically interested in this issue as at one side, LDLR are important targets in BBB-crossing for drug delivery into the CNS (Demeule et al, 2008;Kim et al, 2007;Spencer and Verma, 2007b), and also, cationic protein nanoparticles are biocompatible materials that fulfil most of the requests posed for vehicle-mediated drug 330 delivery into brain (Juillerat-Jeanneret, 2008). Therefore, we analysed ex vivo the signal from the whole brain to avoid the noise coming form the background of the To understand better the stability in circulation and the potential renal clearance of both BBB-crossing and failing constructs, GFP fluorescence was also determined in kidney.…”

“…Being ApoB a well-known BBB-crossing peptide for soluble drugs (Kreuter et al, 2002b) and also when linked to nanoparticles (Kim et al, 2007) (Cespedes et al, 2014;Unzueta et al, 2012) and also for ligand-mediated cell penetrability (Figure 3 and 440 4), the most complex biological barriers imposed by brain vessels might represent a tighter bottleneck to proper biodistribution.…”

Plausible antioxidant biomechanics and anticonvulsant pharmacological activity of brain-targeted β-carotene nanoparticles

“…Polysorbate-80-coated β-carotene nanoparticles (P-80-BCNP) appeared to follow a similar required course of delivery in mimicking the adsorption of low-density lipoprotein, apolipoprotein-E, and apolipoprotein-A1 after their injection into the systemic blood circulation followed by receptor-mediated endocytosis of the nanoparticles by the brain barrier's capillary endothelial cells. 39,40 This hypothesis by Kreuter and Kim was supported by the fact that covalent coupling of apolipoprotein-E and apolipoprotein-A1 to human serum albumin nanoparticles lead to similar endocytosis. [41][42][43] In the present study, polysorbate-80 was used as the coating surfactant for intended β-carotene-loaded nanoparticles for its brainspecific delivery.…”