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. 2023 Jul 20;14(7):449. doi: 10.1038/s41419-023-05991-x

Fig. 8. ApoExos transfer functional PCSK5 mRNA to endothelial cells, increasing cellular PCSK5 protein levels.

Fig. 8

A ApoExo uptake through macropinocytosis increases PCSK5 mRNA expression in endothelial cells. Endothelial cells were treated with ApoExos, ApoBodies, or ExoN for 24 h (upper graph) or exposed to ApoExos and DMSO or ApoExos and EIPA 30 µM for 24 h (lower graph). Control (Ctrl) represents cells treated with RPMI serum-free medium. n ≥ 3 for each condition. B Knockdown of PCSK5 in ApoExos inhibits the increase in PCSK5 mRNA expression in recipient endothelial cells. Endothelial cells were treated with 90 nM ApoExos isolated from endothelial cells transfected with Ctrl (siCtrl) or PCSK5 (siPCSK5) siRNA; n ≥ 3 for each condition. Expression of PCSK5 mRNA was measured by quantitative RT‒PCR, and the result is presented as relative expression of PCSK5 mRNA compared to untreated cells (Ctrl) ± SEM after normalization with HPRT1. C Macropinocytosis-dependent ApoExo uptake increased PCSK5 protein expression. Endothelial cells were exposed to vehicle (Ctrl - DMSO), ApoExos with vehicle (ApoExos + DMSO), or ApoExos + EIPA 30 µM (ApoExos + EIPA) for 24 h. PCSK5 expression was quantified by densitometry and expressed as arbitrary units ± SEM; n ≥ 3. Cropped representative images of immunoblots from the same gel are presented. P values were obtained by unpaired t test (*P < 0.05, **P < 0.01, and ***P < 0.001).