AIM The modified differential proteins of succinylation in vascular endothelial cells under simulated weightlessness were screened and their modified levels were further verified.

METHODS Human umbilical vein endothelial cells (HUVECs) were cultured in vitro. Cell samples were collected from control group and simulated weightlessness group for 6 h and 48 h, and cell precipitation was extracted. Combined tandem mass labeling, high performance liquid chromatography (HPLC), acylated peptide enrichment and mass spectroscopy-based quantitative proteomics were used to further study the different succinylated proteins in HUVECs under simulated weight loss. CO-IP technology was used to further validate the selected proteins and their differentially modified sites.

RESULTS There were significant differences in the succinylation modification of HUVECs under simulated weightlessness (P<0.05) in proteomic analysis; In cells, differentially modified proteins are mainly enriched in mitochondria and endoplasmic reticulum. After 48 hours of simulated weightlessness, the level of PDIA4 succinylation modification in HUVECs was higher than that in the ground normal gravity group (P<0.05), and the difference was statistically significant; The succinylation modification levels of multiple protein sites of PDIA4 in the control group were lower than those in the simulated weightlessness effect group (P<0.05, P<0.01).

CONCLUSION  Simulated weightlessness causes significant changes in the level of succinylation modification of vascular endothelial cell proteins. It has been proved that PDIA4 has multiple succinylation differential modification sites.