Imaging,Therapy And Safety Studies Of Smart Nanoprobes In Atherosclerosis

Atherosclerosis?AS?is a chronic inflammatory disease,characterized by the accumulation of lipids on the arterial wall.Alcohol drinking,hyperlipidemia,cigarette smoking and other exogenous stimuli are major risk factors for AS,and could alter endothelial function.That facilitate monocytes directed migrate into the intima,where they differentiate into macrophages?M??.Lesion progression also involves the immigration of vascular smooth muscle cells?VSMCs?from the media to the intima.Both M?and VSMCs could internalize excess lipoproteins,resulting in the formation of foam cells and inflammatory lipid plaques.Currently,AS has become a major killer for human life due to the acute cardiovascular events caused by plaque rupture.How to achieve the effective diagnosis and cures of AS is still a great challenge in the field of medicine.Current diagnosis techniques have been mainly focused on the imaging of plaque burden and component.The main drawbacks of these techniques are that they can not recognize the aberrant changes at molecular or cellular levels timely.Therefore,they are not suitable for AS early warning and assessment.Existing approaches for AS therapy are implemented via drug treatment or surgery.But series side effects are unavoidable in drug treating,for example,drug is diffusible and unable to regulate in a controlled manner in vivo,which may cause toxic side effects on liver,stomach and muscle.Surgery can not fundamentally prevent the development of plaque or improve the instability of plaque.That,along with AS,especially the lesions in the aortic arch,carotid artery and coronary artery,which are strongly associated with cardiovascular and cerebrovascular diseases,are mainly distributed in the deeper part of the body.Therefore,there is great significance to carry out early diagnosis,plaque development assessment and effective therapy of AS in the field of cardiovascular research.Together with the rapid development of nanotechnology,nanomaterials have been increasingly used in the diagnosis and treatment of many diseases.Firstly,nanomaterials have unique optical properties.For example,upconversion nanoparticles?UCNPs?can be excited upon near-infrared?NIR?irradiation and emit ultraviolet or visible light;Copper sulfide nanoparticles?CuS NPs?have high photothermal conversion efficiency;Graphene oxide?GO?nanosheets are a broad-spectrum quenching agent.Secondly,owing to their unique physical and chemical properties?tunable shapes,sizes,surface properties?,nanomaterials can be used for the conjugation of recognition groups to improve the function of active targeting,which will benefit to realize the dynamic observation and precisely control at cells or protein levels.This may help improve the sensitivity of diagnosis and enhance the effectiveness of the therapy.In addition,the toxic effects of nanomaterials are closely related to their physicochemical properties.We can develop nanomaterials with high safety by adjusting their physical and chemical properties according to the actual biological needs.Therefore,nanomaterials provide new opportunities and changes for solving the problems we meet in the clinic application of AS diagnosis and therapy.At present,nano-diagnostics and nano-therapeutic for AS are based on single biomarker detection or drug delivery,but not all biomarkers retain stable expression,and the efflux of the drug may bring potential cytotoxicity,which will lead to the distortion of diagnostic information and the reduction of efficacy.In this dissertation,a variety of smart nanoprobe based on UCNPs,silicon dioxide?SiO₂?,CuS NPs and GO nanosheets were prepared to solve the problems.These nanoprobe allowing direct visualization of the activity change and location migration of the biomarker in living cells,or realizing the potential of regulation cell signal transduction.This research provided new strategies and tools for improving AS early warning and accurate therapy.We preliminary investigated the impacts of shape on the toxicology of gold nanomaterials,and that may provided guarantee for the sustainable development of nanoprobes used in AS diagnosis and therapy.It mainly includes the following sections:1.M?foam cell formation mediated by CD36 receptor dependent internalization of oxidized low-density lipoprotein?oxLDL?is an important hallmark of early AS.Activation of CD36 and its binding to oxLDL are the key points in foam cell formation.Herein,we develop a site-specific luminescence resonance energy transfer system based on UCNPs@SiO₂-CD36nanoprobe for the simultaneous imaging of CD36 activity and CD36-oxLDL binding on the M?surface.Moreover,using this novel nanoprobe,we also investigate the mechanism by which reactive oxygen species?ROS?signaling enhances the binding of oxLDL to CD36.Because of these advantages,this nanoprobe may provide a versatile platform for monitoring the progression of atherogenesis and elucidating atherogenesis signaling at the cellular level.2.The key event in early AS also includes VSMCs foam cells formation.Recently,transient receptor potential vanilloid subfamily 1?TRPV1?,a thermosensitive cation channel,has been found to protects against foam cell formation through inducing autophagy in oxLDL-treated VSMCs.Here we show that coupling of CuS NPs to antibodies targeting TRPV1 act as a photothermal switch for TRPV1 signaling in VSMCs using near-infrared light.Upon irradiation,local increases of temperature open TRPV1 channels and cause Ca²⁺influx.The increase in intracellular Ca²⁺activates autophagy and impedes foam cell formation in VSMCs treated with oxidized lowdensity lipoprotein.In vivo,CuS-TRPV1 allows photoacoustic imaging of the cardiac vasculature and reduces lipid storage and plaque formation in ApoE^-/^-mice fed a high-fat diet,with no obvious long-term toxicity.Together,this suggests CuS-TRPV1 may represent a therapeutic tool to locally and temporally attenuate atherosclerosis.3.High concentrations of oxLDL induce aberrant apoptosis of VSMCs in AS plaques,and it eventually potentiates plaque disruption and risk for cardiovascular disease.Given the important role of apoptosis inducing factor?AIF?in caspase-independent apoptosis,here we develop an AIF-targeting nanosensor by the assembly of GO nanosheets and dye-labeled DNA hybrid structures.This nanosensor is shown to possess rapid response,high sensitivity,and selectivity for AIF that enables realtime imaging of AIF release in VSMCs.A better assessment of the apoptotic level of VSMCs can be obtained.More importantly,the abundant binding between DNA hybrid structures and AIF inhibits the translocation of AIF into the nucleus and subsequent apoptosis in VSMCs.Taking together,this novel nanosensor may help evaluate the extent of atherosclerotic lesions and reduce the risk of heart attack and stroke.4.Nanomaterials provide new methods for AS diagnosis and therapy because of their unique physicochemical properties,but their potential adverse effects on human health have been rarely explored.High surface-to-volume ratio,unique thermal and optical behaviors make gold nanoparticles?Au NPs?suitable for the application of AS.However,recent studies showed that Au NPs exhibited physicochemical properties dependent cytotoxicity,and induced the overproduction of ROS.ROS have been implicated as an initiator of endothelial injury in AS,but existing toxicity assessment relies mostly on the adverse outcome of oxidative stress damage.The stepwise oxidative modifications process remains largely unknown.Considering the strong oxidability and high reactivity of ROS,oxidative modification of key proteins may be the major molecular initiating event.Therefore,Au NPs with varying shape were synthesized,and their effects on endothelial function-related proteins oxidative modification were measured,which is crucial in the proper construction of smart nanoprobe in research of AS diagnosis and therapy.