ICAM-1-mediated Lung-targeted Dexamethasone-Loaded Nanoparticles For Acute Lung Injury Therapy

Acute lung injury(ALI)is one of the most common critical illness with few curable treatments available and has become a serious burden for both patients and society.It has been suggested that Nuclear Factor Kappa B(NF-kB)signaling is crucial in the initiation of the inflammatory response.Glucocorticoid can block the NF-kB signaling to prevent or alleviate acute lung injury.However,its application is limited due to the side effects of glucocorticoid.Based on dexamethasone(DEX),this study aimed to construct intercellular adhesion molecule 1 modified DEX conjugated nanostructured lipid carriers(NLCs),to aid the successful and efficient delivery of DEX to the lung.The new drug plays a therapeutic effect with a decreased potential side effect,thus providing a theoretical basis for the clinical treatment of acute lung injury.Employing monostearin(MS)as a solid lipid,medium chain triglycerides(MCT)as liquid lipid,polyethylene glycol monostearate(PEG2000-SA)and monoamino-terminated polyethylene glycol monostearate(NH2-PEG2000-SA)as amphiphilic lipid material,an anionic dexamethasone nanostructured lipid carrier was prepared by aqueous solvent diffusion method.N,N'-succinimidyl carbonate was assigned as a chain bridge to prepare anti-ICAM-1 monoclonal antibody modified anionic dexamethasone nanostructured lipid carriers(ICAM/DEX/NLCs)and anti-IgG monoclonal antibody modified anionic dexamethasone nanostructured lipid carriers(IgG/DEX/NLCs).Because surface charge has a crucial impact on the pharmacokinetics of nanoparticles in the body,a 3%mass of MS was substituted by 3%octadecylamine(ODA)to keep total amount of lipid constant.Same method was applied to prepare anti-ICAM-1 monoclonal antibody modified cationic dexamethasone nanostructured lipid carriers(ICAM/DEX/ODA-NLCs)and anti-IgG monoclonal antibody modified cationic dexamethasone nanostructured lipid carriers(IgG/DEX/ODA-NLCs),in order to further investigate and compare the physical and chemical properties of anionic and cationic DEX/NLCs,as well as the therapeutic response to ALI.The prepared ICAM/DEX/NLCs,IgG/DEX/NLCs,ICAM/DEX/ODA-NLCs and IgG/DEX/ODA-NLCs nanoparticles were round and uniform in size.The particle size of four DEX/NLCs(ICAM/DEX/NLCs,IgG/DEX/NLCs,ICAM/DEX/ODA-NLCs and IgG/DEX/ODA-NLCs)were 249.9 ±21.5 nm,229.3±17.2 nm,235.9±1.8nm,227.9±7.4 nm,respectively.The Zeta potentials of them were 30.3±0.5 mV,-28.7±1.1 mV,37.4±0.7 mV and 34.2±3.3 mV;the encapsulation rates were 90.11%±1.34%,86.72±%10.84%,82.93%±0.94%and 81.39%±3.23%,respectively.Drug loadings were 3.62%±0.05%,3.49%±0.03%,3.34%±0.04%and 3.28%±0.13%,respectively.In vitro release study showed that the DEX loaded in NLCs could be released continuously for more than 24 h,with the cumulative release rate being above 59.0%.To investigate the cytotoxicity of these four DEX/NLCs,human vascular endothelial cell line(EAhy926)was chosen as model cells while lipopolysaccharide(LPS)stimulation was employed to construct ALI inflammatory endothelial cell model.The cellular inhibition rates of all these DEX/NLCs were dose-dependent.The median lethal doses(IC50)of anionic ICAM/DEX/NLCs and IgG/DEX/NLCs were above 600?g/mL,while that of cationic ICAM/DEX/ODA-NLCs and IgG/DEX/ODA-NLCs were less than 600 ?g/mL,with the values of IC50 decrease with the addition of ODA.Cell uptake studies indicated that,compared to ICAM/DEX/ODA-NLCs,the uptake efficiency of ICAM/DEX/NLCs was lower at resting EAhy926 cells whereas higher at activated EAhy926 cells;compared to IgG/DEX/NLCs,the uptake efficiency of ICAM/DEX/NLCs on activated EAhy926 cells was significantly higher.These results suggested that anionic ICAM/DEX/NLCs were potentially more efficient in transporting dexamethasone to activated endothelial cells,thereby increasing the ability to target the abnormal endothelium.Cell transport studies indicated that ICAM/DEX/NLCs were taken up by cells via the ICAM-1 receptor-mediated endocytic pathway.Balb/c mice were exploited to construct the ALI animal model by trachea exposure of drip lipopolysaccharide.The lung distribution of DEX/NLCs in healthy mice and ALI mouse models was examined by intravenous administration of the tail vein.Compared with ICAM/DEX/NLCs,IgG/DEX/NLCs had higher lung distribution both in healthy mice and ALI mouse models;compared to ICAM/DEX/NLCs,the lung distribution of ICAM/DEX/ODA-NLCs were lower in healthy mice while higher in the ALI mouse model.These results suggested that anionic ICAM/DEX/NLCs potentially deliver DEX to the lung of the ALI mice in a more efficient way,thereby improving the therapeutic effect on abnormal lung.In addition,in vivo drug administration of DEX,ICAM/DEX/NLCs,IgG/DEX/NLCs,ICAM/DEX/ODA-NLCs,and IgG/DEX/ODA-NLCs in ALI mouse models was investigated by tail vein injection.After 24 h of administration,compared with other drugs,the ICAM/DEX/NLCs had a stronger inhibition on the levels of TNF-a and IL-6 inflammatory factors and inflammatory cell infiltration in the lungs of mice.The pathological morphology of lung tissue was observed by HE staining at 12 h and 24 h after administration.ICAM/DEX/NLCs presented more significantly improvement of pathological characterization in ALI mouse model compared with other drugs,including inflammatory cell infiltration,hyperemia and alveolar septal thickening.Our results showed that compared to cationic ICAM/DEX/ODA-NLCs,anionic ICAM/DEX/NLCs prepared in our study have lower cytotoxicity,improved cell internalization characteristics and lung distribution ability in mice with ALI.They have a potentially improved lung distribution of DEX in the ALI mouse model through a better binding to pulmonary vascular endothelial cell.The administration of ICAM/DEX/NLCs may be expected to reduce drug side effects and achieve safe and effective treatment for ALI.