Huang-Lian-Jie-Du Decoction Attenuates Atherosclerosis and Increases Plaque Stability in High-Fat Diet-Induced ApoE-/- Mice by Inhibiting M1 Macrophage Polarization and Promoting M2 Macrophage Polarization.

Yueyao Zhang,Wei Wu,He Chen,Rong Li,Zhexing Mai,Yijun Wang,Siwen Ma,Qunzhang Zhan,Yinhe Cai,Haiyi Li,Chuanjin Luo,Junmao Wen

doi:10.3389/fphys.2021.666449

Abstract

Macrophage polarization plays a vital impact in triggering atherosclerosis (AS) progression and regression. Huang-Lian-Jie-Du Decoction (HLJDD), a famous traditional Chinese decoction, displays notable anti-inflammatory and lipid-lowering effects in different animal models. However, its effects and mechanisms on AS have not been clearly defined. We determined whether HLJDD attenuated atherosclerosis and plaques vulnerability by regulating macrophage polarization in ApoE−/− mice induced by high-fat diet (HFD). Furthermore, we investigated the effects of HLJDD on macrophage polarization in oxidized low-density lipoprotein (ox-LDL) induced RAW264.7 cells. For in vivo assay, compared with the model group, HLJDD ameliorated lipid metabolism, with significantly decreased levels of serum triglyceride, total cholesterol (CHOL), and lipid density lipoprotein. HLJDD suppressed serum tumor necrosis factor α (TNF-α) and IL-1β levels with increased serum IL-10 level, and inhibited mRNA level of NLRP3 inflammasome in carotid tissues. HLJDD enhanced carotid lesion stability by decreasing macrophage infiltration together with increased expression of collagen fibers and α-SMA. Moreover, HLJDD inhibited M1 macrophage polarization, which decreased the expression and mRNA levels of M1 markers [inducible nitric oxide synthase (iNOS) and CD86]. HLJDD enhanced alternatively activated macrophage (M2) activation, which increased the expression and mRNA levels of M2 markers (Arg-1 and CD163). For in vitro assay, HLJDD inhibited foam cell formation in RAW264.7 macrophages disturbed by ox-LDL. Besides, groups with ox-LDL plus HLJDD drug had a lower expression of CD86 and mRNA levels of iNOS, CD86, and IL-1β, but higher expression of CD163 and mRNA levels of Arg-1, CD163, and IL-10 than ox-LDL group. Collectively, our results revealed that HLJDD alleviated atherosclerosis and promoted plaque stability by suppressing M1 polarization and enhancing M2 polarization.

Highlights

Atherosclerosis (AS) is recognized as the predominant pathological basis of cardiovascular diseases (CVDs; Frostegård, 2013; Bäck et al, 2019)
We explored the role of Huang-Lian-Jie-Du Decoction (HLJDD) on macrophage polarization in ApoE−/− mice fed a high-fat diet (HFD) and RAW264.7 macrophages induced by oxidized low-density lipoprotein
Effects of HLJDD on RAW264.7 Cells Viability In ApoE−/− mice experiments, we found that HLJDD alleviated AS and promoted plaque stability by modulating macrophage polarization

Summary

Introduction

Atherosclerosis (AS) is recognized as the predominant pathological basis of cardiovascular diseases (CVDs; Frostegård, 2013; Bäck et al, 2019). Intimal macrophages lead to the maintenance of atherosclerotic inflammatory responses, and participate in the whole processes of AS (Barrett, 2020). Numerous studies have emphasized the critical ability of macrophage polarization to trigger atherosclerosis progression and regression (Koelwyn et al, 2018; Shapouri-Moghaddam et al, 2018). M1 polarized macrophages and subsequent releases of inflammatory cytokines such as inducible nitric oxide synthase (iNOS), interleukin 6 (IL-6), and tumor necrosis factor α (TNF-α) play a crucial mediator role in accelerating AS (Wang et al, 2014). In response to the cytokines IL-4 and IL-13, M2 macrophages are polarized and secrete anti-inflammatory factors such as IL-10 and collagen (Huang et al, 2014), which exerts anti-inflammatory properties and increases the stability of AS plaques (Rahman et al, 2017). Inhibiting phenotypic conversion of macrophages to M1 and enhancing M2 enrichment may be a potential strategy to prevent and attenuate atherosclerosis

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