Effect of nanoparticles binding ß-amyloid peptide on nitric oxide production by cultured endothelial cells and macrophages

Abstract

Background: As part of a project designing nanoparticles for the treatment of Alzheimer's disease, we have synthesized and characterized a small library of nanoparticles binding with high affinity to the β-amyloid peptide and showing features of biocompatibility in vitro, which are important properties for administration in vivo. In this study, we focused on biocompatibility issues, evaluating production of nitric oxide by cultured human umbilical vein endothelial cells and macrophages, used as models of cells which would be exposed to nanoparticles after systemic administration. Methods: The nanoparticles tested were liposomes and solid lipid nanoparticles carrying phosphatidic acid or cardiolipin, and PEGylated poly(alkyl cyanoacrylate) nanoparticles (PEG-PACA). We measured nitric oxide production using the Griess method as well as phosphorylation of endothelial nitric oxide synthase and intracellular free calcium, which are biochemically related to nitric oxide production. MTT viability tests and caspase-3 detection were also undertaken. Results: Exposure to liposomes did not affect the viability of endothelial cells at any concentration tested. Increased production of nitric oxide was detected only with liposomes carrying phosphatidic acid or cardiolipin at the highest concentration (120 µg/mL), together with increased synthase phosphorylation and intracellular calcium levels. Macrophages exposed to liposomes showed a slightly dose-dependent decrease in viability, with no increase in production of nitric oxide. Exposure to solid lipid nanoparticles carrying phosphatidic acid decreased viability in both cell lines, starting at the lowest dose (10 µg/mL), with increased production of nitric oxide detected only at the highest dose (1500 µg/mL). Exposure to PEG-PACA affected cell viability and production of nitric oxide in both cell lines, but only at the highest concentration (640 µg/mL). Conclusion: Liposomal and PEG-PACA nanoparticles have a limited effect on vascular homeostasis and inflammatory response, rendering them potentially suitable for treatment of Alzheimer's disease. Moreover, they highlight the importance of testing such nanoparticles for production of nitric oxide in vitro in order to identify a therapeutic dose range suitable for use in vivo.

Biodegradable Nanoparticles for Delivery of Therapeutics in CNS Infection

“…Most PACAs are safe to use since they are biodegradable and can be easily made in large quantities (Ćurić et al 2015). Modified PACA nanoparticles have been used in studies involving neurodegenerative diseases such as Alzheimer’s since it has the ability to cross the BBB and cause minimal inflammation (Orlando et al 2013). A 2013 study used several types of nanoparticles including PACA to deliver phosphatidic acid or cardiolipin to the brain (Orlando et al 2013).…”

“…Modified PACA nanoparticles have been used in studies involving neurodegenerative diseases such as Alzheimer’s since it has the ability to cross the BBB and cause minimal inflammation (Orlando et al 2013). A 2013 study used several types of nanoparticles including PACA to deliver phosphatidic acid or cardiolipin to the brain (Orlando et al 2013). These nanoparticles were found to be a potential therapeutic for Alzheimer’s due to their limited effect on vascular homeostasis (Orlando et al 2013).…”

“…A 2013 study used several types of nanoparticles including PACA to deliver phosphatidic acid or cardiolipin to the brain (Orlando et al 2013). These nanoparticles were found to be a potential therapeutic for Alzheimer’s due to their limited effect on vascular homeostasis (Orlando et al 2013). However, they may cause an increase in nitric oxide production in target cells when using high doses (Orlando et al 2013)…”

“…These nanoparticles were found to be a potential therapeutic for Alzheimer’s due to their limited effect on vascular homeostasis (Orlando et al 2013). However, they may cause an increase in nitric oxide production in target cells when using high doses (Orlando et al 2013)…”

“…These alternative methods include microemulsion templates, coacervation, solvent-based, membrane contactor, melt- emulsification and supercritical fluid technology methods (Gastaldi et al 2014). For example, the melt-emulsification method, a technique generally thought of as a safer alternative to high pressure homogenization, melts lipids, then a stabilizer is added, then the solution is diluted and slowly cooled so the nanoparticles form with a solid lipid center with phospholipid and a stabilizer on the outside (Orlando et al 2013). …”