CCR2-Overexpressing hydrogelated macrophages facilitate targeted lipid clearance and immunomodulation in atherosclerosis treatment
H Yu, C Ma, H X song, C H yan, Y L HanAbstract
Background/Purpose
Atherosclerosis (AS) is a chronic inflammatory condition caused by lipid buildup and immune dysregulation in arteries. Existing treatments fail to effectively address both lipid absorption and inflammation simultaneously at the plaque site. Herein, this study develops a novel anti-atherosclerotic platform (CCR2+ HMSCS) by loading sulfated chitosan (SCS) into hydrogelized macrophages (HM) and overexpressing CCR2, hereby achieving triple effects of lipid adsorption, plaque targeting, and anti-inflammatory action in AS treatment.
Methods
SCS loaded HM (HMSCS) were created by integrating HAMA-loaded SCS hydrogel into macrophages using freeze-thaw cycles and UV crosslinking. CCR2 overexpression was achieved through lentiviral transfection. In vitro, lipid adsorption, ox-LDL uptake, macrophage polarization, and foam cell formation were assessed using ELISA, flow cytometry, immunofluorescence, and RT-PCR. In vivo, ApoE⁻/⁻ mice on a Western diet received bi-weekly intravenous injections of saline, SCS, HM, HMSCS, or CCR2+ HMSCS for 4 weeks. Plaque burden, lipid profiles, inflammation, and targeting efficiency were evaluated using Oil Red O staining, histology, immunofluorescence, and IVIS imaging.
Results
HMSCS demonstrated a reduction in LDL-c levels by up to 40% and facilitated the conversion of M1 to M2 macrophages under LPS stimulation. Furthermore, HMSCS preserved membrane integrity and protein functionality, thereby enabling immune evasion. IVIS imaging indicated that CCR2+ HMSCS exhibited enhanced targeting of atherosclerotic plaques. In ApoE⁻/⁻ mice, CCR2+ HMSCS significantly decreased serum TG, TC, and LDL-c levels, and reduced aortic plaque area by 89% compared to control groups. Immunofluorescence analysis revealed fewer CD86+ M1 macrophages, more CD163+ M2 macrophages, and reduced CD36+ foam cells in atherosclerotic plaques. RT-PCR analysis showed downregulation of pro-inflammatory genes (TNF-α, IL-1β, MMP9) and upregulation of lipid efflux transporters (ABCA1, ABCG1, SRBI). Organ histology and serum assays confirmed favorable biosafety, with clearance primarily through the hepatobiliary pathway.
Conclusions
CCR2+ HMSCS offer a new, biocompatible cell-based platform for targeted lipid adsorption, anti-inflammatory reprogramming, and plaque-specific delivery, effectively remodeling the atherosclerotic microenvironment and showing promise for clinical use in cardiovascular disease.