Background: Pulmonary arterial hypertension (PAH) is a common complication of congenital heart disease (CHD). Extracellular vesicles (EVs) are small endosome- derived membrane microvesicles that play a prominent role in intercellular communication by carrying signaling molecules, such as proteins, mRNAs, and microRNAs.
Methods: We obtained peripheral blood from irreversible CHD-PAH group and reversible CHD-PAH group and normal control group, and then isolated EVs from peripheral blood (PB-EVs) and monocytes/ macrophages (MC-EVs). We compared the effects of PB-EVs and MC-EVs from above three groups on the proliferation using Cell Counting Kit-8(CCK-8), migration using the transwell chamber assay, and phenotypic transformation of HPASMCs via detecting the expression of contractile phenotype markers and synthetic phenotype markers of HPASMCs by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and immunoblotting assay.
Results: In this study, PB-EVs or MC-EVs from the irreversible and reversible CHD-PAH groups each enhanced HPASMC proliferation and migration compared with PB- or MC-EVs from the normal control group, which was most pronounced for the irreversible CHD-PAH group. Besides, PB- or MC-EVs from the irreversible and reversible CHD-PAH groups showed increased expression of synthetic phenotype markers and migration-related molecules and decreased expression of contractile phenotype markers compared with PB- or MC-EVs from the normal control group, especially in the case of the irreversible CHD-PAH group. Moreover, the level of phosphorylation of p38 in HPASMCs co-cultured with PB- or MC-EVs from the irreversible and reversible CHD-PAH groups were markedly higher than those in HPASMCs co-cultured with PB- or MC-EVs from the normal control group.
Conclusions: In summary, our results indicated that EVs from peripheral blood of CHD-PAH patients could promote switching of HPASMCs from a quiescent contractile to a proliferative, migratory, and synthetic phenotype.