The anti-atherosclerotic effect of Paeonol against the lipid accumulation in macrophage-derived foam cells by inhibiting ferroptosis via the SIRT1/NRF2/GPX4 signaling pathway.

Atherosclerosis (AS) is the underlying cause of many severe vascular diseases and is primarily characterized by abnormal lipid metabolism. Paeonol (Pae), a bioactive compound derived from Paeonia Suffruticosa Andr., is recognized for its significant role in reducing lipid accumulation. Our research objective is to explore the link between lipid buildup in foam cells originating from macrophages and the process of ferroptosis, and explore the effect and mechanism of Pae on inhibiting AS by regulating ferroptosis. In our animal model, ApoE-deficient mice, which were provided with a high-fat regimen to provoke atherosclerosis, were administered Pae. The treatment was benchmarked against simvastatin and ferrostatin-1. The results showed that Pae significantly reduced aortic ferroptosis and lipid accumulation in the mice. In vitro experiments further demonstrated that Pae could decrease lipid accumulation in foam cells induced by oxidized low-density lipoprotein (LDL) and challenged with the ferroptosis inducer erastin. Crucially, the protective effect of Pae against lipid accumulation was dependent on the SIRT1/NRF2/GPX4 pathway, as SIRT1 knockdown abolished this effect. Our findings suggest that Pae may offer a novel therapeutic approach for AS by inhibiting lipid accumulation through the suppression of ferroptosis, mediated by the SIRT1/NRF2/GPX4 pathway. Such knowledge has the potential to inform the creation of novel therapeutic strategies aimed at regulating ferroptosis within the context of atherosclerosis.

Paeonol Attenuates Atherosclerosis by Inhibiting Vascular Smooth Muscle Cells Senescence via SIRT1/P53/TRF2 Signaling Pathway.

Atherosclerosis is a chronic inflammatory disease leading to various vascular diseases. Vascular smooth muscle cell (VSMC) senescence promotes atherosclerotic inflammation and the formation of plaque necrosis core, in part through telomere damage mediated by a high-fat diet. Our previous research found that paeonol, a potential anti-inflammatory agent extracted from Cortex Moutan, could significantly improve VSMCs dysfunction. However, the impact of paeonol on the senescence of VSMCs remains unexplored. This study presents the protective effects of paeonol on VSMCs senescence, and its potential activity in inhibiting the progression of atherosclerosis in vivo and in vitro. Sirtuin 1 (SIRT1) is a nuclear deacetylase involved in cell proliferation, senescence, telomere damage, and inflammation. Here, SIRT1 was identified as a potential target of paeonol having anti-senescence and anti-atherosclerosis activity. Mechanistic studies revealed that paeonol binds directly to SIRT1 and then activates the SIRT1/P53/TRF2 pathway to inhibit VSMCs senescence. Our results suggested that SIRT1-mediated VSMCs senescence is a promising druggable target for atherosclerosis, and that pharmacological modulation of the SIRT1/P53/TRF2 signaling pathway by paeonol is of potential benefit for patients with atherosclerosis.

Paeonol Attenuates the Endothelial-to-Mesenchymal Transition Induced by TGF-ß1 in Human Umbilical Vein Endothelial Cells through ALK5- Smad2/3 Signaling Pathway.

BACKGROUND: Paeonol (Pae), the main active compound of the root of Paeonia albiflora, is efficacious in treating atherosclerosis (AS). Endothelial dysfunction is throughout the pathological progression of AS. It is expected that inhibition of Endothelial-to-mesenchymal transition (EndMT) will be a key target for AS treatment. OBJECTIVE: In this study, we investigated the molecular mechanism of the regulatory effect of Pae on EndMT in human umbilical vein endothelial cells (HUVECs). METHODS: Cell cytotoxicity, proliferation, and migration were detected by CCK-8, the wound healing assay, and EdU staining, respectively. The protein expressions were measured by Western blot or immunofluorescence staining. Immunofluorescence staining was performed to indicate endothelial cells undergoing EndMT in ApoE-/- mice. In vitro TGF-ß1-induced EndMT assays were performed in HUVECs and the effect of Pae was explored. RESULTS: We demonstrated that Pae could improve induced TGF-ß1-EndMT in vivo and in vitro. Mechanism study revealed that Pae directly bonds to the activin-like kinase 5 (ALK5, also known as TGFß type I receptor), inhibited downstream Smad2/3 phosphorylation, and thus alleviated EndMT. Notably, overexpression of ALK5 significantly reversed the inhibitory effect of Pae on EndMT in HUVECs. CONCLUSION: Our results indicate that ALK5 is a promising druggable target for AS, and pharmacological regulation of ALK5-Smad2/3 signaling pathway with small-molecule holds great potential to benefit AS patients.