Application Of PLGA Nanoparticles And MiRNA-99a Overexpressing Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes In Cardiac Repair

Background: The cardiac regeneration ability of adult mammals is very limited,and it is difficult to effectively compensate the lost cardiomyocytes in acute myocardial infarction.Exogenous cardiomyocytes injection and promoting endogenous cardiomyocytes proliferation can repair the injured heart.PLGA nanoparticles loaded with small molecular compounds can prolong and enhance the efficacy and durability of small molecular substances in myocardial repair.Objective: To investigate the therapeutic effect of PLGA nanoparticles loaded with TT-10(TT-10-NP)and micro-RNA-199 a activating the cell cycle of human induced pluripotent stem cell derived cardiomyocytes(hi PSC-CMS)on myocardial repair after myocardial infarction.Methods:(1).Small molecule compound TT-10 was encapsulated into PLGA nanoparticles,and then TT-10-NP was injected into the myocardium of mouse acute myocardial infarction model.TT-10 solution treatment group(TT-10-SOL group),empty PLGA nanoparticles treatment group(Empty NP group),DPBS treatment group(DPBS group)and sham operation group(Sham group)were used as controls.(2).The left anterior descending coronary artery of immunodeficient(NOD /SCID)mice was ligated to establish the acute myocardial infarction model.Mice were randomly divided into four groups: AAV-6-mir-199 a group,AAV-6-control group,MI and Sham group.Cardiac echocardiography was performed at the corresponding time points to record the left ventricular function parameters.Myocardial infarction area was evaluated by Sirius red / Fast green staining.Engraftment rate was evaluated by immunofluorescence staining of cells that expressed the human variant of cardiac troponin T(hc Tn T).Cell proliferation was assessed via detection of cell cycle markers: Ki67,Brd U,PH3,and Aurora B.Results: In vitro,10 u M TT-10 treatment increased the positive rate of hi PSC-CMs cell cycle markers(Ki67,Brd U,PH3 and Aurora B)by at least 4 times(P < 0.01),the apoptosis rate of hi PSC-CMS decreased significantly(P < 0.05),and the number of hi PSC-CMS positive for nuclear Yap protein increased significantly(P < 0.01);Intramyocardial injection of TT-10-NP significantly improved left ventricular function,reduced myocardial infarction area and myocardial hypertrophy(P <0.05);The positive rate of Yap protein in myocardial nucleus and the number of proliferating cardiomyocytes in TT-10-NP group were significantly higher than those in other treatment groups,while the number of apoptotic cardiomyocytes was significantly lower in TT-10-NP group(P < 0.01).Mir-199 a over-expression promoted the proliferation of hi PSC-CMS by activating Yap / TAZ signaling pathway(P < 0.05);One month after operation,the left ventricular function and infarction area of mice in AAV-6-mir-199 a group were significantly better than those in other groups(P < 0.05);The number of transplanted cells in AAV-6-mir-199 a group was significantly higher than that in AAV-6-control group(P < 0.05);The positive rate of cell cycle markers in AAV-6-mir-199 a group was significantly higher than that in AAV-6-control group(P < 0.05),while mi R-199 a overexpression did not significantly reduce the apoptosis of hi PSC-CMS.Conclusions: PLGA nanoparticles loaded with TT-10 and hi PSC-CMS overexpressing mi R-199 a significantly reduce the infarction area and improve cardiac function in mice after acute myocardial infarction,which provides a new idea for the clinical treatment of myocardial infarction.