Impact of Nanoparticle Physicochemical Properties on Protein Corona and Macrophage Polarization

Abstract

Macrophages, the major component of the mononuclear phagocyte system, uptake and clear systemically administered nanoparticles (NPs). Therefore, leveraging macrophages as a druggable target may be advantageous to enhance NP-mediated drug delivery. Despite many studies focused on NP−cell interactions, NP-mediated macrophage polarization mechanisms are still poorly understood. This work aimed to explore the effect of NP physicochemical parameters (size and charge) on macrophage polarization. Upon exposure to biological fluids, proteins rapidly adsorb to NPs and form protein coronas. To this end, we hypothesized that NP protein coronas govern NP−macrophage interactions, uptake, and subsequent macrophage polarization. To test this hypothesis, model polystyrene NPs with various charges and sizes, as well as NPs relevant to drug delivery, were utilized. Data suggest that cationic NPs potentiate both M1 and M2 macrophage markers, while anionic NPs promote M1-to-M2 polarization. Additionally, anionic polystyrene nanoparticles (APNs) of 50 nm exhibit the greatest influence on M2 polarization. Proteomics was pursued to further understand the effect of NPs physicochemical parameters on protein corona, which revealed unique protein patterns based on NP charge and size. Several proteins impacting M1 and M2 macrophage polarization were identified within cationic polystyrene nanoparticles (CPNs) corona, while APNs corona included fewer M1 but more M2-promoting proteins. Nevertheless, size impacts protein corona abundance but not identities. Altogether, protein corona identities varied based on NP surface charge and correlated to dramatic differences in macrophage polarization. In contrast, NP size differentially impacts macrophage polarization, which is dominated by NP uptake level rather than protein corona. In this work, specific corona proteins were identified as a function of NP physicochemical properties. These proteins are correlated to specific macrophage polarization programs and may provide design principles for developing macrophage-mediated NP drug delivery systems.

Bone‐Targeted Nanoparticle Drug Delivery System‐Mediated Macrophage Modulation for Enhanced Fracture Healing

“…[ 20,21,25,33,34 ] Data suggest that unloaded TBP‐NP also promotes M1‐to‐M2 macrophage polarization, albeit to a far less extent (4‐fold vs 12‐fold) than TBP‐NP AR28 , consistent with our previous findings that specific proteins within the adsorbed corona varied based on NP surface charge and correlated with dramatic differences in macrophage polarization. [ 19 ] Nevertheless, M2 phenotypic enhancement was significantly greater in TBP‐NP AR28 treated groups (Figure 3A,C). This trend was also supported via gene expression analysis, where there was significant downregulation of M1‐related genes and upregulation of M2‐related genes after TBP‐NP AR28 treatment, compared with free AR28 or TBP‐NP treatment.…”

“…[ 16 ] Previous data suggested that the underlying healing mechanism enhanced osteogenesis due to upregulated Wnt‐β‐catenin signaling in regenerative cells, such as mesenchymal stem cells. However, our recent work implicating M1‐to‐M2 macrophage polarization of anionic PSMA‐b‐PS NPs used here [ 19 ] combined with the growing understanding of the role of macrophages in fracture healing, motivated us to revisit underlying healing mechanism of TBP‐NP delivery of AR28.…”

“…However, the M1 phenotype percentage slightly decreased, and the M2 macrophage percentage increased, resulting in a significant increase in M2/M1 ratio at day 10, compared with saline and AR28, which could underpin increased bone volume and torsional rigidity at week 4. The physicochemical properties of NP impact macrophage modulation; previous data [ 19 ] showed that anionic PSMA‐b‐PS NP promotes M2 and inhibits M1 macrophage polarization in vitro, which is further associated with increased M2/M1 ratio during fracture healing to enhance healing from TBP‐NP alone in vivo. In summary, improved fracture healing of TBP‐NP AR28 is correlated with increased M2/M1 ratios during bone repair.…”

“…However, our recent work indicates the impact of anionic NP, including PSMA‐b‐PS NP used here, on macrophage polarization, motivating the reevaluation of the healing mechanism via TBP‐NP AR28 . [ 19 ]…”

Immunomodulatory Effects of Nanoparticles on Dendritic Cells in a Model of Allergic Contact Dermatitis - Importance of PD-L2 Expression

“…Differences in the corona protein composition or abundance could alter the NPs interaction with the BMDCs. Corona composition is highly dependent on surface charge 84 . Si20nm and mTiO2 are both negatively charged so we anticipate that similar compositional coronas would form but this should be confirmed in proteomics studies.…”