Pulsatilla chinensis functions as a novel antihyperlipidemic agent by upregulating LDLR in an ERK-dependent manner

Background: Pulsatilla chinensis (PC) is a traditional Chinese medicine (TCM) known for its beneficial activities. It has been historically used to treat dysentery, vaginal trichomoniasis, bacterial infections, and malignant tumors. The therapeutic potential of PC in the management of hypercholesterolemia remains largely unexplored.

Methods: A high-throughput screening based on high-throughput sequencing was conducted in HepG2 cells to construct gene expression profiles for several hundred TCMs. In vivo evaluation of the efficacy of PC was performed using rats with hypercholesterolemia. Transcriptome analysis was carried out on PC-treated rat livers and HepG2 cells to investigate the mechanism of action of PC in vitro. The findings were further validated using RT-qPCR and western blot techniques.

Results: PC was identified as similar to Rhizoma Coptidis based on signature genes related to metabolism. Administration of PC via gavage in rats with hypercholesterolemia for 11 weeks resulted in substantially reduced serum total cholesterol and low-density lipoprotein (LDL) cholesterol and ameliorated fatty liver. Transcriptome analysis revealed that PC regulated various pathways associated with lipid metabolism. The LDL receptor (LDLR), a key player in cholesterol metabolism, was upregulated by PC both in vivo and in vitro. It was discovered that PC achieved this upregulation by activating extracellular regulated protein kinase (ERK) signaling in HepG2 cells. To uncover the major bioactive components responsible for the anti- hypercholesterolemia effect of PC, two major saponins, named Pulsatilla saponin D (PCD) and PC anemoside B4 (PCB4), were assessed. PCD, but not PCB4, was identified as the active ingredient responsible for the upregulation of LDLR by PC.

Conclusion: These findings demonstrated that PC acts as an antihypercholesterolemic agent by upregulating LDLR in an ERK-dependent manner and holds potential in the treatment of hypercholesterolemia.