Mesenchymal stem cell (MSC) exosomes may limit cardiac injury, and even reverse cardiac damage in animal models of
ischemia. To understand exosome-mediated improvement in cardiac function we examined the proteomic alternations in the MSC exosome-treated mice hearts subjected to left coronary artery (LCA)
ligation, with particular emphasis on peri-
infarct areas. At 7 days after LCA
ligation, left ventricular end systolic thickness,
infarct size and survival of mice were studied. Mass spectrometric analysis of
infarct and peri-
infarct areas was carried out. Expression of inflammatory markers (LOX-1 and NLRP3) and cell death markers (Bax, Bcl-2,
Caspases 1 and 3 and GSDMD) were investigated by Western blots and immunofluorescence. Proteomic analysis of the
infarct and peri-
infarct areas in saline-treated hearts revealed differentially expressed
proteins involved in
inflammation and apoptotic cell death, while showing depletion of processes governing cell death. Exosome treatment significantly improved the proteomic profile in both
infarct and peri-
infarct areas, more so in the peri-
infarct areas. The
infarct size was smaller (9 ± 1%), and cardiac contractile function (fractional shortening) was preserved in the exosome-treated mice (28 ± 2%). Survival of exosome-treated mice was also better. White blood cell accumulation in and around the
infarct area, expression of LOX-1 and NLRP3
inflammasome, and markers of cell death (cleaved
Caspase-3,
Caspase-1, GSDMD, Bcl-2 and Bax) were dramatically reduced by MSC exosome treatment (all p < 0.01). In cultured primary mouse cardiomyocytes, treatment with MSC exosomes essentially reversed
inflammation-induced pro-apoptotic and inflammatory signals (p < 0.01). MSC exosomes exert their cardioprotective effects by suppressing
inflammation and pro-apoptotic processes, particularly in the peri-
infarct areas, resulting in preservation of cardiac function after LCA
ligation.