DHZCP Modulates Microglial M1/M2 Polarization via the p38 and TLR4/NF-κB Signaling Pathways in LPS-Stimulated Microglial Cells.

Lu Zhou,Xia Xu,Weiru Zhang,Dongsheng Wang,Zhicheng Gong,Yang Wang,Xinjian Qiu

doi:10.3389/fphar.2020.01126

Lu Zhou, Xia Xu + Show 5 more

Open Access

https://doi.org/10.3389/fphar.2020.01126

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Abstract

Intracerebral hemorrhage (ICH) is a disease with a significantly high rate of morbidity, mortality and disability. Inhibition of inflammation is considered a potential strategy for improving the clinical symptoms induced by ICH. The hallmark of neuroinflammation is microglial activation. Microglia can polarize into either the classically activated M1 (proinflammatory) phenotype, exacerbating neuronal damage, or the alternatively activated M2 (antiinflammatory) phenotype, exerting neuroprotection and promoting neuronal recovery. Promoting microglial polarization to the M2 phenotype may be a viable strategy for treating neuroinflammation. Several studies have indicated that promoting blood circulation and removing blood stasis exhibits therapeutic effects on intracerebral hemorrhage. Dahuang Zhechong Pill (DHZCP), a classical recipe that promotes blood circulation and removes blood stasis, has been reported to improve the clinical outcome of ICH. DHZCP has been shown to exert antiinflammatory effects. However, the detailed antiinflammatory mechanism of DHZCP in ICH has rarely been investigated. In this study, DHZCP inhibited lipopolysaccharide (LPS)-induced M1 microglial activation. DHZCP exerted antiinflammatory effects, by inhibiting LPS-induced M1 proinflammatory cytokine (TNF-α and IL-6), and iNOS production and increasing M2 antiinflammatory cytokine (IL-10) production. DHZCP also switched microglial polarization from M1 to M2, as indicated by significantly increased expression of M2 polarization markers (CD209, and CD206) and markedly decreased expression of an M1 polarization marker (CD54). In addition, DHZCP inhibited p38 and TLR4/NF-κB signaling activation, as demonstrated by inhibition of LPS-induced increases in p-p38, TLR4 and nuclear factor kappa B p-65 (NF-κB p-65) protein expression. Taken together, DHZCP modulates microglial M1/M2 polarization via the p38 and TLR4/NF-κB signaling pathways to confer antiinflammatory effects.

Highlights

Intracerebral hemorrhage (ICH) is a disease with a significantly high rate of morbidity, mortality and disability that lacks effective therapies (Wang and Dore, 2007; Zhou et al, 2014; Zeng et al, 2016)
Evidence suggests that inflammation critically contributes to ICH-induced brain injury, such as hematoma and neuron injury (Zhang et al, 2006; Zhou et al, 2014), and in return, hematoma triggers inflammatory signaling through microglial activation (Zhou et al, 2014)
To explore whether rat serum containing Dahuang Zhechong Pill (DHZCP) promoted M2 polarization of LPS-treated microglial cells, the expression level of CD209 was measured by flow cytometry

Summary

Introduction

Intracerebral hemorrhage (ICH) is a disease with a significantly high rate of morbidity, mortality and disability that lacks effective therapies (Wang and Dore, 2007; Zhou et al, 2014; Zeng et al, 2016). A thorough understanding of the pathogenesis of ICH-induced secondary brain injury is crucial, especially inflammatory mechanisms (Wang et al, 2007; Zhou et al, 2014). Evidence suggests that inflammation critically contributes to ICH-induced brain injury, such as hematoma and neuron injury (Zhang et al, 2006; Zhou et al, 2014), and in return, hematoma triggers inflammatory signaling through microglial activation (Zhou et al, 2014). To investigate the mechanisms of ICH-induced inflammatory injury, microglial activation is a point of concern for researchers (Zhou et al, 2014)

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