| Atherosclerotic cardiovascular disease(ASCVD)is the leading cause of death worldwide.Lowering blood low-density lipoprotein cholesterol(LDL-C)is the basic treatment for atherosclerosis.Traditional lipid-lowering drugs such as statins and novel PCSK9 inhibitors can significantly reduce LDL-C levels and cardiovascular events in patients.However,despite intensive lipid-lowering,some patients still have a high risk of cardiovascular events.In recent years,clinical studies have shown that inflammation may be one of the reasons for the residual risk.Cholesterol crystals(CCs)in plaques can promote plaque macrophage inflammation through multiple pathways.Clinical evidence suggests that CCs are associated with vulnerable plaque and poor prognosis.Therefore,targeting CCs in plaques may help reduce the residual cardiovascular risk.Nevertheless,there is currently no clinical drug available for dissolving CCs.High-density lipoprotein(HDL)has various anti-atherosclerotic effects such as anti-inflammation,inducing cholesterol efflux,and dissolving CCs,but its ability to dissolve CCs is weak.Objective: Based on the properties of HDL to dissolve CCs,this study aimed to develop an HDL-like nanoparticle(NP)with efficient CC dissolution and evaluate the effect of this novel NP on atherosclerosis in vitro and in vivo.Methods: By changing the phospholipid composition of nanomaterials,different HDL-like NPs were synthesized,and the NPs with the strongest ability to dissolve CCs(named mi Nano)were selected for the follow-up research.First,the biodistribution and intraplaque accumulation of mi Nano in atherosclerotic mice were examined using fluorescent-labeled mi Nano.Next,mi Nano was administered to atherosclerotic mice through the tail vein,and the effect of mi Nano on atherosclerosis was explored by detecting the aortic plaque area,intraplaque CC area,intra-plaque macrophages,and plaque stability.The in vivo safety of mi Nano was explored by blood biochemical indicators and morphological examination of major organs.In order to explore the effect of mi Nano on macrophage inflammation,we used primary mouse peritoneal macrophages(PM)and human monocyte THP-1-differentiated macrophages to detect 1)the effect of mi Nano on oxidized low-density lipoprotein(ox LDL)-induced foam cell formation in macrophages,2)the effect of mi Nano on CC-induced macrophage inflammation and 3)the mechanisms by which mi Nano affects macrophage inflammation.Finally,human atherosclerotic plaques were collected to explore whether mi Nano could dissolve CCs in human plaques.Results: In vitro,mi Nano could bind to CC,dissolve CC in a timeand dose-dependent manner,and induce cholesterol efflux in macrophages.In atherosclerotic mice,mi Nano aggregated in plaques and co-localized with CCs and macrophages within plaques.In addition,mi Nano effectively reduced atherosclerotic plaque formation in mice,reduced CC-area and macrophage infiltration within plaques,and improved plaque stability.In terms of safety,mi Nano had no significant toxcity on liver and kidney function,blood routine,and major organs in mice.Mechanistic studies have shown that mi Nano can reduce ox LDLand CC-induced macrophage inflammation and inhibit macrophage foam cell formation by inhibiting the TKR4/NF-κB pathway.Furthermore,mi Nano can effectively dissolve CCs in isolated human atherosclerotic plaques.Conclusion: This study shows that the phospholipid-based NP,mi Nano,is expected to slow down the development of atherosclerosis and stabilize the plaques by targeting CC and macrophages in atherosclerotic plaques,thus providing new treatment strategies for atherosclerosis. |
