Qingre Huoxue Decoction Alleviates Atherosclerosis by Regulating Macrophage Polarization Through Exosomal miR-26a-5p

Background: Qingre Huoxue Decoction (QRHX) is a classical Chinese herbal prescription widely used in clinical practice for the treatment of atherosclerosis (AS). Our previous study demonstrated its efficacy in stabilizing plaque and improving prognosis, as well as its ability to regulate macrophage polarization. This study aimed to further investigate the effects of QRHX on AS and explore the underlying mechanisms.

Methods: ApoE^-/- mice were fed a high-fat diet (HFD) for 8 weeks in order to establish an AS model. Oil Red O, H&E, Masson, and IHC staining were employed to assess lipid accumulation, plaque development, collagen loss and target of the aortas tissue. ELISA was employed to measure the levels of TNF-α and IL-10 in serum. Dual luciferase reporter assay was conducted to ascertain the connection between miR-26a-5p and PTGS2 in vitro. Western blot and RT-qPCR assay were conducted to assess the NF-κB signaling pathway and macrophage polarization. The effects of miR-26a-5p were tested after transfecting miR-26a-5p over-expressive lentivirus.

Results: QRHX attenuated HFD-induced plaque progression and inflammation of AS model mice. BMDM-derived exosomes (BMDM-exo) increased miR-26a-5p and decreased PTGS2 expressions, inhibited the NF-κB signaling pathway and regulated macrophage polarization in vivo. These effects of BMDM-exo were further enhanced after QRHX intervention. Dual luciferase reporter assay results showed that miR-26a-5p directly binds to the 3'-UTR of PTGS2 mRNA and regulates the expression of PTGS2. The miR-26a-5p of BMDM-exo played a key role in macrophage polarization. After overexpression of miR-26a-5p, the NF-κB signaling pathway was inhibited and macrophages were converted from M1 to M2 in vitro.

Conclusion: QRHX can exert anti-inflammatory and plaque-stabilizing effects through exosomal miR-26a-5p via inhibiting the PTGS2/NF-κB signaling pathway and regulating macrophage phenotype from M1 to M2 polarization in AS.