Construction of an inflammatory microenvironment-responsive HDL-mimetic nanoparticle and evaluation of its in vitro anti-atherosclerotic activity

Abstract

Objective To construct an inflammation-responsive high-density lipoprotein (HDL)-mimetic nanoparticle with anti-atherosclerotic activity using a bioinspired strategy based on a oxidation-responsive material. Methods 4-(hydroxymethyl) phenylboronic acid pinacol ester (PBAP) was chemically conjugated to β-cyclodextrin (β-CD) to synthesize a reactive oxygen species (ROS)-sensitive material.Nanoprecipitation and coextrusion methods were used to prepare HDL-mimetic nanoparticles (mHDL NP).Spectroscopy was employed to verify the structure of the synthesized material, and microscopy was utilized to observe the morphology of the nanoparticles. We observed phagocytosis of the nanoparticles by murine RAW264. 7 macrophages using flow cytometry and confocal microscopy, and examined the release of the inflammatory factors tumor necrosis factor-α (TNF-α) and monocyte chemoattractant protein-1 (MCP-1) in the supernatant by the macrophages cultured in the presence of the nanoparticles using ELISA. We also used a fluorescent ROS probe DCFH-DA to detect the changes of ROS generated in RAW264. 7 macrophages in response to the nanoparticles. Different methods were used to assess the effects of the nanoparticles on cholesterol efflux and foam cell formation in RAW264. 7 cells. Results Spectroscopy analysis showed that about 5 PBAP units were conjugated to each β-CD molecule. The prepared nanoparticles had a well-defined spherical shape with a narrow size distribution and a mean diameter of about 200 nm. In vitro experiments showed that RAW264. 7 cells phagocytosed the nanoparticles in a time- and dose-dependent manner. mHDL NP significantly inhibited the secretion of the inflammatory factors and ROS production by RAW264. 7 cells in response to inflammatory stimulation (P < 0. 05), which demonstrated potent anti-inflammatory and antioxidant activities of the nanoparticles. mHDL NP time- and concentration-dependently promoted cholesterol efflux(P < 0. 05) and significantly inhibited foam cell formation in RAW264. 7 macrophages. Conclusions We successfully synthesize HDL-mimetic nanoparticles with antioxidant and reverse cholesterol transport capacities. Our preliminary in vitro cellular evaluations demonstrate obvious anti-atherosclerotic activity of the synthesized nanoparticles.

Keywords

• inflammatory microenvironment responsiveness
• nano-drug
• atherosclerosis
• high-density lipoprotein
• reverse cholesterol transport