NPR1 modulates DNA replication in vascular endothelial cells via the transcription factor E2F2

Natriuretic peptide receptor 1 (NPR1) plays a crucial role in maintaining the functionality of vascular endothelial cells. However, its role in regulating DNA replication and genome stability in endothelial cells remains unexplored.

This study aimed to investigate whether NPR1 deficiency disrupts DNA replication and induces DNA damage in human umbilical vein endothelial cells (HUVECs), and to explore the mechanistic role of the E2F transcription factor 2 (E2F2) in this process.

RNA-sequencing analysis was performed in NPR1-deficient HUVECs. EdU incorporation assay quantified DNA replication activity. qPCR or RNA-seq evaluated expression of DNA replication-related genes. DNA damage levels were assessed via phosphorylated histone H2AX (γH2AX). The proteins of NPR1, E2F2 and γH2AX were examined by Western blot. E2F2 was knocked down or overexpressed in NPR1-deficient HUVECs to validate its regulatory role.

DNA replication related genes were downregulated in NPR1-knockdown HUVECs. This result was supported by a decrease of EdU positive rate of HUVECs upon NPR1 deficiency. Downregulation of DNA replication genes (DSCC1, EXO1, MCM4, MCM6, TREX1 and CCNE2) was observed in NPR1-deficient cells. NPR1 knockdown increased γH2AX, particularly in EdU-positive cells. NPR1 silencing reduced the expression of E2F2. E2F2 knockdown mimicked NPR1 deficiency, suppressing DNA replication genes and increasing DNA damage. Additionally, overexpression of E2F2 recovered the DNA replication and mitigated DNA damage in NPR1-knockdown HUVECs.

NPR1 deficiency declines DNA replication activity and induces DNA damage in vascular endothelial cell by inhibiting E2F2 expression. This provides further insights into the underlying mechanism on NPR1 in the regulation of the functionality of vascular endothelial cells.