Preparation, characterization, and safety evaluation of poly(lactide-co-glycolide) nanoparticles for protein delivery into macrophages

Abstract

Following infection, HIV establishes reservoirs within tissues that are inaccessible to optimal levels of antiviral drugs or within cells where HIV lies latent, thus escaping the action of anti-HIV drugs. Macrophages are a persistent reservoir for HIV and may contribute to the rebound viremia observed after antiretroviral treatment is stopped. In this study, we further investigate the potential of poly(lactic- co -glycolic) acid (PLGA)-based nanocarriers as a new strategy to enhance penetration of therapeutic molecules into macrophages. We have prepared stable PLGA nanoparticles (NPs) and evaluated their capacity to transport an active molecule into the human monocyte/macrophage cell line THP-1 using bovine serum albumin (BSA) as a proof-of-concept compound. Intracellular localization of fluorescent BSA molecules encapsulated into PLGA NPs was monitored in live cells using confocal microscopy, and cellular uptake was quantified by flow cytometry. In vitro and in vivo toxicological studies were performed to further determine the safety profile of PLGA NPs including inflammatory effects. The size of the PLGA NPs carrying BSA (PLGA-BSA) in culture medium containing 10% serum was ~126 nm in diameter, and they were negatively charged at their surface (zeta potential =−5.6 mV). Our confocal microscopy studies and flow cytometry data showed that these PLGA-BSA NPs are rapidly and efficiently taken up by THP-1 monocyte-derived macrophages (MDMs) at low doses. We found that PLGA-BSA NPs increased cellular uptake and internalization of the protein in vitro. PLGA NPs were not cytotoxic for THP-1 MDM cells, did not modulate neutrophil apoptosis in vitro, and did not show inflammatory effect in vivo in the murine air pouch model of acute inflammation. In contrast to BSA alone, BSA encapsulated into PLGA NPs increased leukocyte infiltration in vivo, suggesting the in vivo enhanced delivery and protection of the protein by the polymer nanocarrier. We demonstrated that PLGA-based nanopolymer carriers are good candidates to efficiently and safely enhance the transport of active molecules into human MDMs. In addition, we further investigated their inflammatory profile and showed that PLGA NPs have low inflammatory effects in vitro and in vivo. Thus, PLGA nanocarriers are promising as a drug delivery strategy in macrophages for prevention and eradication of intracellular pathogens such as HIV and Mycobacterium tuberculosis .

Anti-Invasive and Anti-Proliferative Effects of shRNA-Loaded Poly(Lactide-Co-Glycolide) Nanoparticles Following RAN Silencing in MDA-MB231 Breast Cancer Cells

“…The results in Table I show that inclusion of PEG to the PLGA NP did reduce the negative zeta potential but this caused an increase in cell viability rather than a decrease as was expected (Table II ). This finding has been observed in other work [ 42 ]. The data in Table I also shows that the double emulsion procedure is able to achieve impressive encapsulation efficiencies in nanoparticles that are spherical and smooth (Fig.…”

Designing drug-free biodegradable nanoparticles to modulate inflammatory monocytes and neutrophils for ameliorating inflammation

“…We initially investigated the response of blood leukocytes to particles in vitro, with the leukocytes obtained from mice at the initial stages of EAE where the numbers of inflammatory monocytes and neutrophils increase in the circulation, and are maximal prior to the onset of EAE [38,39]. We tested two in vitro particles concentrations (20 and 200 μg/ mL), as particle concentration influenced the internalization and activity of both monocytederived macrophages and neutrophils [40,41]. Blood leukocytes were isolated at day 9 following disease induction, which is one or two days prior to clinical disease onset, and then were incubated with particles for 0.5, 1, and 3 hours, either at 20 or 200 μg/mL.…”

Imaging techniques in nanomedical research

“… 51 The same approach was used to test PEGylated NPs 52 and cyclodextrin-based NPs 6 for enhanced tumour cell internalization and cytotoxicity, or gold nanoclusters for fluorescence imaging and enhanced drug transport, 53 or poly(lactide-co-glycolide) NPs for protein delivery to macrophages. 54 Combination of CFM and flow cytometry also allowed understanding the effect of functionalization on the uptake of dense-silica NPs by gastric cancer cells, 8 or the influence of anaesthetics on the internalization efficacy of dendrimers by microglial cells. 55 …”