Elsevier

Carbohydrate Polymers

Volume 296, 15 November 2022, 119940
Carbohydrate Polymers

Hyaluronic acid-guided assembly of ceria nanozymes as plaque-targeting ROS scavengers for anti-atherosclerotic therapy

https://doi.org/10.1016/j.carbpol.2022.119940Get rights and content

Highlights

  • Polymer-guided assembly of ceria nanozymes were prepared via green synthesis.

  • HA-CeO2 NPs had superior SOD-mimic activities with higher amounts of cerium (III).

  • HA-CeO2 NPs had superior cell protection ability from ROS-induced damage.

  • HA-CeO2 NPs inhibited endocytosis of ox-LDL and downregulated of serum LDL.

Abstract

Oxidative stress is a distinguishing feature in atherosclerosis disease. Reactive oxygen species (ROS) can increase the oxidized low density lipoprotein (ox-LDL) and oxidative damage to macrophages in the plaque. Although antioxidant agents such as N-acetylcysteine are used to treat atherosclerosis, but provide a poor clinical benefit to the majority of patients with atherosclerosis. Here we have designed hyaluronic acid-guided assemblies of ceria nanozymes (HA-CeO2 NPs) as novel plaque-targeting ROS scavengers. The introduction of hyaluronic acid not only provide the stability and biocompatibility, but also surprisingly enhance SOD-mimic activities of ceria nanozymes compared to bare CeO2 precipitates, dextran or poly-aspartic acid coated ceria nanozymes. Interestingly, we find HA-CeO2 NPs not only actively target plaque-associated macrophages in atherosclerosis to remove superfluous ROS and protect macrophages from ROS-caused damages, but also effectively inhibit endocytosis of ox-LDL by activated macrophages. We believe HA-CeO2 nanozymes can serve as a simple and promising platform for anti-atherosclerotic therapy.

Introduction

Nowadays atherosclerosis related cardio vascular disease (CVD) remains a leading cause of vascular disease worldwide (Luscher, 2019). Emerging evidence has demonstrated that excessive reactive oxygen species (ROS) can aggravate the progress of atherosclerosis (LoPresti et al., 2019; Malekmohammad et al., 2019; Vinchi et al., 2020). The excess accumulation of ROS in atherosclerosis increases the production of oxidized low density lipoprotein (ox-LDL) that can stimulate the formation of plaques (Boren et al., 2020). Recent studies have also illustrated ROS-mediated oxidized phospholipids are pro-inflammatory and facilitate the progression of atherosclerosis (Que et al., 2018). In addition, ROS can directly cause oxidative damage to vascular endothelial cells (Xiao et al., 2019) and macrophages (Fang et al., 2021). Antioxidant agents such as Vitamin E (Steinberg, 1995), Vitamin C (Ekuni et al., 2009), and N-acetylcysteine (Andrews et al., 2001) were used to relieve atherosclerosis, while these antioxidant therapies provided a poor clinical benefit to the majority of patients with atherosclerosis. Inflammatory microenvironment in the atherosclerosis could accelerate the application of nanoparticles for anti-atherosclerosis therapy (Ou et al., 2021). Nanoparticles could enter plaque site via increased permeability of the endothelium and exerted excellent therapeutic effects in atherosclerosis (Wu et al., 2020).

Currently cerium oxide nanozymes have raised extensive attention for their SOD-mimic and catalase-mimic activities depending on the Ce3+/Ce4+ ratio (Neal et al., 2021).The SOD-mimic activities endowed nanozymes with critical functions in redox process, such as antioxidant effects, anti-inflammatory effects and neuroprotection (Singh et al., 2021). Besides, ceria-based nanozymes can prevent chemotherapy-induced acute kidney injury without interference with chemotherapeutics through rapid removal of ROS (Zhang et al., 2020). It is inspiring for the wide application of ceria nanozymes in the field of nanomedicine. While the reported ceria nanozymes were mainly prepared with oleylamine to form lipid-like bilayer structure, which might cause low compatibility and reduced enzyme-mimic activities.

Recently polymer-guided assembly of nanoparticles has emerged as a novel approach to fabricate functional nanomaterials with desired properties for nanomedicine (Yi et al., 2020). Coating of biodegradable polymers can also provide excellent stability and biocompatibility of inorganic nanoparticles (Baldim et al., 2020). Hyaluronic acid, a natural polysaccharide, exhibits desirable biocompatibility and biodegradability and has been extensively applied in novel drug delivery systems (Xia et al., 2018). Studies have demonstrated excellent selectivity of hyaluronan nanoparticles toward pro-inflammatory macrophage phenotype (Mu et al., 2020; Parayath et al., 2018). Further investigation illustrates the expression of the HA receptor, CD44, is elevated in atherosclerosis-associated macrophages. Thus, HA-based therapeutics have been applied for atherosclerosis treatment owing to highly efficient internalization of HA-based formulation which is motivated by CD44-mediated endocytosis (Cao et al., 2022). In this paper, biocompatible hyaluronic acid-guided assemblies of HA-CeO2 NPs were prepared as plaque-targeting ROS scavengers to remove excessive ROS in atherosclerosis. Dextran or poly-aspartic acid (PASP)-coated ceria nanoparticles were prepared as comparative study.

It was reported that molecularly imprinted ceria nanocomposites (CeO2@MIP) were synthesized to mediate unique cholesterol efflux and inhibit inflammation for the treatment cholesterol-mediated atherosclerosis (Wen et al., 2022). While CeO2@MIP were prepared in a complex route and the molecularly imprinted polymers intensively reduced the amounts of cerium (III) in CeO2@MIP, which induced sharply declined SOD-mimic activities. Interestingly, in our primitive research, we found the coating of hyaluronic acid not only stabilized ceria nanozymes, but also increased the amounts of cerium (III) in CeO2, which might result in enhanced SOD-mimic activities compared to bare CeO2 precipitates dextran or poly-aspartic acid coated nanozymes. Therefore, the hypothesis to be testified in this study is focused on the exploration of hyaluronic acid-guided nanozyme system for targeting and improving the anti-atherosclerotic effect. As depicted in Scheme 1, hyaluronic acid-guided assembly of ceria nanozymes as plaque-targeting ROS scavengers is simply constructed via green synthesis for anti-atherosclerotic therapy, which is expected to improve compatibility and stability of CeO2 nanozymes, as well as exert higher SOD mimic activities with the increased proportion of Ce (III)/Ce (IV). Besides, the excellent selectivity of hyaluronan nanoparticles toward pro-inflammatory macrophage makes HA-CeO2 NPs producing enhanced effects on atherosclerotic treatment via the actively targeting plaque. Finally, HA-CeO2 NPs can improve the anti-atherosclerotic effects with multiple pathways, such as reduction of ox-LDL and cell protection from excessive ROS-caused damage. Both in vitro and in vivo experiments are performed to investigate its physiochemical properties and anti-atherosclerotic effect.

Section snippets

Materials, cells and animals

Hyaluronic acid (MW: 6 kDa) was obtained from Bloomage biotech. Cerium nitrate hexahydrate, sodium of poly-aspartic acid (MW: 7 kDa) and dextran (MW: 8 kDa) were purchased from Macklin Biochemical (Shanghai, China) Total superoxide dismutase assay kit, Hoechst 3342, and RIPA lysis buffer were obtained from Beyotime Biotechnology (Shanghai, China) 5,5-Dimethyl-1-pyrrolineN-oxide was supplied by Sigma-Aldrich (Shanghai, China). Recombinant IFN-γ Mouse was provided by Bioworld Technology

Results and discussion

Firstly three biocompatible polymers (hyaluronic acid, dextran and poly-aspartic acid) were adopted for the preparation of functional ceria nanozymes. The polymer-coated nanozymes were prepared through green method without the addition of any organic solvent (Fig. 1a). The crystal structures of polymer-coated CeO2 nanozymes were characterized by X-ray diffraction. HA-CeO2 NPs, Dex-CeO2 NPs and PASP-CeO2 NPs had the same characteristic peaks of CeO2 at 111°, 220°, 311°, 331° (Fig. 1b), which

Conclusions

In summary, this study proposed hyaluronic acid-guided assembly of CeO2 nanozymes to improve the targeting and treatment of atherosclerosis. In vitro experiments confirmed that the HA-CeO2 NPs not only stabilized ceria nanozymes, but also increased the amounts of cerium (III) in CeO2, which resulted in enhanced SOD-mimic activities compared to bare CeO2 precipitates, dextran or poly-aspartic acid coated ceria nanozymes. Moreover, hyaluronic acid-guided CeO2 assemblies could strongly scavenge

Credit authorship contribution statement

Wang Sheng, Zhang Jingwen: Conceptualization, Methodology and experiment performer, Writing Original draft. Li Wei: Animal experiment assistance. Tu Jiasheng and Du Yunai: Supervision. Sun Chunmeng: Writing- Reviewing and Editing,

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

This work was funded by the National Natural Science Foundation of China (82003679), the Ministry of Science and Technology of the People's Republic of China (2017ZX09101001006). The authors also thank the public platform of the State Key Laboratory of Natural Medicines (China Pharmaceutical University) for assistance with cell-associated experiments.

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