Rhein Attenuates Neointimal Hyperplasia by Inhibiting VSMC Proliferation via MAPK-Mediated Downregulation of CDC45.

Background

Neointimal hyperplasia (NH) is the primary cause of vascular complications following arterial interventions, driven mainly by abnormal proliferation and phenotypic switching of vascular smooth muscle cells (VSMC). Rhein, a natural anthraquinone compound, possesses anti-inflammatory and anti-proliferative properties. However, its role in regulating VSMC phenotype and neointimal formation remains unclear.

Methods

The therapeutic effects of Rhein were evaluated in a murine model of femoral artery injury and in primary human VSMC stimulated with platelet-derived growth factor (PDGF). Network pharmacology and RNA sequencing were employed to identify potential targets and signaling pathways. The regulatory mechanisms were investigated using RT-qPCR, immunofluorescence, immunoblotting, and flow cytometry.

Results

Rhein treatment significantly reduced neointimal formation and the neointima/media ratio in the femoral artery injury model. In vitro, Rhein dose-dependently suppressed PDGF-induced VSMC phenotypic switching and proliferation, and arrested the VSMC in the G0/G1 phase. RNA sequencing identified cell division cycle 45 (CDC45) as a key mediator of Rhein's inhibitory effect on VSMC abnormal proliferation, which was confirmed by knockdown and overexpression experiments. Furthermore, Rhein could bind to multiple MAPK pathway proteins and inhibit ERK1/2 phosphorylation, and specific inhibition of ERK phosphorylation downregulated the PDGF-induced increase of CDC45 expression, implicating MAPK signaling in its pharmacological mechanism.

Conclusion

Rhein alleviates neointimal hyperplasia by inhibiting VSMC phenotypic switching and aberrant proliferation, an effect primarily driven by the suppression of MAPK signaling, downregulating CDC45 expression and consequently arresting the cell cycle at the G0/G1 phase to exert its antiproliferative effect.