含LRRK2的huMSCs衍生的外泌体通过恢复mCa2+外流减轻脓毒症心肌细胞线粒体钙超载OA

AIM:This study aimed to investigate the mechanism through which leucine-rich repeat kinase 2(LRRK2)contained in exosomes from human umbilical cord-derived mesenchymal stem cells(huMSCs-exo)alleviates mi-tochondrial calcium(mCa2+)overload in septic cardiomyocytes by restoring mCa2+efflux.METHODS:Mice were ran-domized into three groups:sham(n=10),cecal ligation and perforation(CLP)(n=20),and CLP+huMSCs-exo(n=20).Sepsis was induced via CLP,and huMSCs-exo were administered via tail vein injection 1 h prior to surgery.Cardiac func-tion was assessed by echocardiography 24 h after the surgery,and histopathological changes in myocardial tissue were ex-amined using hematoxylin-eosin staining.huMSCs-exo were obtained by ultracentrifugation.Human cardiomyocyte AC16 cells were divided into six experimental groups:control,lipopolysaccharide(LPS),LPS+huMSCs-exo,LPS+huMSCs-exo+ruthenium red(Ru-R),LPS+huMSCs-exo+si-RNA(control siRNA),and LPS+huMSCs-exo+si-LRRK2(LRRK2 siRNA),with three replicates per group.For all groups,except the control group,AC16 cells were co-cultured with huM-SCs-exo and treated with LPS for 12 h.For the Ru-R treatment group,AC16 cells were pre-treated with Ru-R for 30 min.To investigate the role of LRRK2,LRRK2-silenced huMSCs were constructed using siRNA,and the corresponding exo-somes derived from these cells were subsequently co-cultured with AC16 cells in the presence of LPS for 12 h.mCa2+lev-els were measured using the Rhod-2 AM probe,mitochondrial membrane potential(MMP)was assessed by JC-1 staining,mitochondrial structure was observed via transmission electron microscopy,adenosine triphosphate(ATP)content was quantified using the biochemical method,creatine kinase MB isoenzyme(CK-MB)and lactate dehydrogenase(LDH)lev-els were determined via ELISA,and apoptosis was evaluated using TUNEL staining.RESULTS:Survival analysis showed a survival rate of 50%in the CLP group and 80%in the CLP+huMSCs-exo group.Compared with the sham group,mice in the CLP group exhibited impaired cardiac function,disorganized myocardial fiber arrangement,visible necrotic cells,interstitial edema,and inflammatory cell infiltration,along with significantly elevated serum levels of CK-MB and LDH(P<0.01).In contrast,mice in the CLP+huMSCs-exo group demonstrated markedly improved cardiac function,at-tenuated myocardial pathological damage,and significantly reduced serum levels of CK-MB and LDH(P<0.01)com-pared to the CLP group.In cell experiment,compared with the control group,the LPS group showed significantly in-creased levels of CK-MB and LDH in AC16 cells(P<0.01),markedly enhanced apoptosis,increased levels of mCa2+,as well as reduced levels of MMP,ATP,and LRRK2 protein expression.Compared with the LPS group,the LPS+huMSCs-exo group demonstrated decreased levels of CK-MB and LDH in AC16 cells(P<0.01),significantly reduced apoptosis,decreased levels of mCa2+,as well as increased levels of MMP,ATP(P<0.01),and LRRK2 protein expression.Com-pared with the LPS+huMSCs-exo group,the LPS+huMSCs-exo+Ru-R group exhibited increased levels of MMP but re-duced levels of MMP,l CK-MB,and LDH(P<0.01).Further analysis confirmed that huMSCs-exo could transfer LRRK2 mRNA into AC16 cells.Compared with the LPS+huMSCs-exo+si-RNA group,the LPS+huMSCs-exo+si-LRRK2 group dis-played significantly elevated levels of mCa2+,CK-MB,and LDH in AC16 cells(P<0.01).CONCLUSION:huMSCs-exo containing LRRK2 ameliorate mitochondrial calcium overload by restoring mCa2+efflux,thus alleviating LPS-induced cardiomyocyte injury.