The Effect And Mechanism Of Telmisartan—Angiotensin 1-7 Based Dual-Drugs Nano-Assemblies On Mice Myocardial Infarction Therapy

Background:Renin-angiotensin system(RAS),a primary pharmacological target in cardiovascular medicine,is regulated by angiotensin-converting enzyme/angiotensin?/angiotensin ?-type 1 receptor axis(ACE/Ang ?/AT1R)and angiotensin-converting enzyme 2/angiotensin 1-7/MasR axis(ACE2/Ang1-7/MasR).The latter axis counteracts the adverse myocardial remodeling effect of the former,thus maintaining heart homeostasis.After myocardial infarction(MI),excessive activation of RAS leads to impaired cardiac function via the overexpressed AT1R in the infarcted site.Telmisartan(Tel)and Ang1-7,which have protective effects on the heart post-MI,are drugs acting on the two axes,respectively.Self-assembling peptide-based biomaterials are promising nanomaterials due to their versatility,ease of manufacturing,low costs,tunable structures,and versatile properties.Therefore,a modified self-assembling Ang1-7(SAA1-7)was designed and co-assembled with Tel to form a dual-drugs nano-assemblies(DDNA),which was expected to improve cardiac dysfunction after myocardial infarction.Aims:To investigate the therapeutic effect and related mechanism of dual-drugs nano-assemblies(DDNA)on myocardial infarction in mice.Method and results:1.Prepared SAA1-7,tested its self-assembly performance and stability.Screened out a suitable ARB drug(Tel)for co-assembly through molecular docking.DDNA was obtained by co-assembly of the two drugs,and the following parameters were determined:microstructure,critical micelle concentration,rheological parameters,fluorescence emission spectrum,drug loading rate,drug release profile,and interaction with MasR.The results showed that SAA1-7 exhibited better stability compared with natural Angl-7.After co-assembly,Tel was doped into the fiber of Angl-7 to form a new nanofiber structure.The critical micelle concentration,rheological parameters,and fluorescence emission spectra indicated that the presence of aromatic groups in Tel and SAA1-7 effectively promotes both hydrophobic and ?-?stacking interactions.Thus,a much more stable system was formed.At the same time,DDNA presented a moderate drug loading rate and a stable drug release profile and still had good interaction with MasR.2.Myocardial infarction model was established,and fluorescent-labeled DDNA was injected through the tail vein to detect the drug distribution in vivo.The experiment groups included:Sham,MI,DDNA,T+A,Tel,Ang1-7,Vehicle.The following parameters were compared:echocardiography,Masson staining,immunohistochemical staining of TGF-? 1 and Caspase-3,immunofluorescence of?-SMA,serum level of IL-6,TNF-?,Creatinine(CR),and ALT.The results showed that DDNA acquired the ability to target myocardial infarction site,and could significantly inhibit apoptosis,inflammation,and adverse myocardial remodeling in mice post-MI.The effect was better than that of the mixture group as well as the monotherapy groups with excellent biocompatibility.3.Cardiomyocytes were cultured under oxygen-glucose deprivation(OGD),and the co-localization of DDNA and AT1R was detected by fluorescence microscopy.Cellular drug uptake was measured by flow cytometry.Tunel staining was used to detect the level of apoptosis,and Western blot was used to detect the expression of apoptosis-related proteins and NF?B.Reactive oxygen species(ROS)expression was detected,and inflammatory factors level were measured by RT-qPCR.The fibrosis model was established by the use of Ang ? and hypoxia-induced conditioned medium(CM)from cardiomyocytes.The migration ability of fibroblasts was detected by the scratch test,and immunofluorescence expression of ?-SMA was tested.The results indicated that the targeted ability of DDNA on cardiomyocytes was mediated by AT1R.DDNA reduced the ratio of Bax/Bcl-2 and expression of c-caspase3 by promoting the phosphorylation of AKT.DDNA inhibited the inflammatory response by suppressed the activation of ROS/NF?B.DDNA inhibited fibroblast differentiation by reducing the level of TGF-?1 secreted by cardiomyocytes and counteracted Ang?-induced fibroblast migration.Conclusion:1.Natural Ang1-7 was modified to obtain SAA1-7 with better stability.2.Dual-drugs nano-assemblies based on SAA1-7 and Tel were successfully constructed,which had excellent stability,moderate drug loading rate,and good biocompatibility.3.DDNA showed targeted ability mediated by AT1R.4.DDNA played a protective role in the heart by inhibiting the expression of apoptosis-related proteins,suppressing the activation of ROS/NF?B related inflammation,inhibiting the migration and differentiation of fibroblasts.