3.2 LOX-1 knockout in plasma-derived exosomes alleviated PASMCs phenotypic switching, proliferation and migration
To pinpoint the exact role of LOX-1, LOX-1 was knockout in rats (Olr1-/- ) in order to obtain LOX-1-null exosomes. Our previous study demonstrated that global Olr1deletion ameliorated hypoxia-induced PH and PVR(Ge et al., 2021). Plasma exosomes, isolated from hypoxia-exposed WT orOlr1-/- rats, were with LOX-1 (Exos-WTHypo.) or without LOX-1 (Exos-KOHypo.). Immunofluorescence staining showed that Exos-KOHypo., rather than Exos-WTHypo., increased α-SMA expression but decreased PCNA levels in PASMCs-WT (Fig. 2A). In parallel, Western blotting detected up-regulation of α-SMA and SM22α expression, and down-regulation of PCNA expression in PASMCs-WT treated with Exos-KOHypo. (Fig. 2B-C). The results indicated that PASMCs-WT phenotypic switching was blunted with Exos-KOHypo., in contrast to Exos-WTHypo.. Moreover, EdU staining, flow cytometry and scratch wound healing assay collectively showed the inhibitory effects of Exos-KOHypo. on PASMCs-WT proliferation and migration (Fig. 2D-I). Taken together, the results suggested that the LOX-1 cargo accounted for exosomes inducing PASMCs phenotypic switching, proliferation and migration.