The role and potential mechanism of PEST-containing nuclear protein (PCNP) in endothelial cell angiogenesis in vitro

Retinal neovascularization (RNV) is a pathological hallmark of vision-threatening diseases such as diabetic retinopathy. Current therapies targeting vascular endothelial growth factors (VEGF) have limitations, highlighting the need for novel therapeutic targets. PEST-containing nuclear protein (PCNP) has been implicated in cell cycle regulation and tumorigenesis, but its function in endothelial cells and angiogenesis is unknown. This study aimed to explore the function and underlying mechanisms of PCNP in angiogenesis using an in vitro model. Human umbilical vein endothelial cells (HUVECs) were transfected to achieve PCNP overexpression or knockdown. The effects on key angiogenic processes were evaluated using cell proliferation (CCK-8), migration (wound healing), and tube formation assays. VEGF levels in culture supernatants and cell lysates were quantified by ELISA, Cytometric Bead Array (CBA), and Western blot. To identify potential molecular mechanisms, transcriptome sequencing was performed on PCNP-overexpressing HUVECs. PCNP overexpression significantly inhibited HUVEC proliferation, migration, and tube formation. Conversely, PCNP knockdown promoted these pro-angiogenic processes. Investigation into the role of VEGF yielded complex results; unexpectedly, supernatant VEGF levels were significantly reduced following both PCNP overexpression and knockdown, while intracellular VEGF levels remained unchanged. Transcriptome analysis of PCNP-overexpressing cells revealed a significant enrichment of genes associated with inflammatory signaling pathways, including the Interleukin-17 (IL-17), Tumor Necrosis Factor (TNF), and Nuclear Factor-kappa B (NF-κB) pathways. PCNP is a novel negative regulator of endothelial cell proliferation, migration, and tube formation in vitro. Its mechanism of action does not appear to involve direct modulation of VEGF expression and may instead be mediated through the regulation of key inflammatory signaling pathways. These findings identify PCNP as a potential new factor in the control of angiogenesis, warranting further investigation as a therapeutic target in neovascular diseases.