Toosendanin enhances endothelial repair and prevents inflammation via E2F1 mediated LINC01089

Endothelial dysfunction represents a critical pathological process underlying various cardiovascular diseases, yet therapeutic strategies targeting endothelial repair remain limited. This study investigated whether toosendanin (TSN), a tetracyclic triterpenoid from Melia toosendan, promotes endothelial repair and suppresses inflammation through novel molecular mechanisms. Human dermal microvascular endothelial cells (HDMECs) and human umbilical vein endothelial cells (HUVECs) were treated with TSN (0-20 μM) and assessed for proliferation, inflammatory responses, and molecular changes using Cell Counting Kit-8 (CCK-8) assays, 5-ethynyl-2'-deoxyuridine (EdU) incorporation, quantitative real-time PCR (qPCR), Western blotting, enzyme-linked immunosorbent assay (ELISA), and RNA sequencing (RNA-seq) analysis. TSN significantly enhanced endothelial cell proliferation in a dose- and time-dependent manner, with maximal effects at 10-20 μM. Under inflammatory conditions, TSN markedly attenuated tumor necrosis factor-α (TNF-α)-induced upregulation of adhesion molecules (intercellular adhesion molecule-1 [ICAM-1], vascular cell adhesion molecule-1 [VCAM-1]), chemokine secretion (C-C motif chemokine ligand 2 [CCL2], and C-X-C motif chemokine ligand 1 [CXCL1]). RNA-seq analysis identified LINC01089 as the most significantly upregulated long non-coding RNA following TSN treatment. Functional studies revealed that TSN upregulates transcription factor E2F transcription factor 1 (E2F1), which directly activates LINC01089 transcription, establishing a positive feedback loop essential for both pro-proliferative and anti-inflammatory effects. LINC01089 knockdown significantly impaired TSN's beneficial effects, while overexpression rescued E2F1 knockdown phenotypes. This study provides the first evidence that TSN enhances endothelial repair and prevents inflammation through the E2F1-mediated upregulation of LINC01089, representing a novel therapeutic mechanism for treating vascular diseases characterized by endothelial dysfunction.