Brazilian Red Propolis Attenuates Inflammatory Signaling Cascade in LPS-Activated Macrophages

Abstract

Although previous studies suggested an anti-inflammatory property of Brazilian red propolis (BRP), the mechanisms involved in the anti-inflammatory effects of BRP and its activity on macrophages were still not elucidated. This study aimed to evaluate whether BRP attenuates the inflammatory effect of LPS on macrophages and to investigate its underlying mechanisms. BRP was added to RAW 264.7 murine macrophages after activation with LPS. NO production, cell viability, cytokines profile were evaluated. Activation of inflammatory signaling pathways and macrophage polarization were determined by RT-qPCR and Western blot. BRP at 50 μg/ml inhibited NO production by 78% without affecting cell viability. Cd80 and Cd86 were upregulated whereas mrc1 was down regulated by BRP indicating macrophage polarization at M1. BRP attenuated the production of pro-inflammatory mediators IL-12, GM-CSF, IFN-Ɣ, IL-1β in cell supernatants although levels of TNF- α and IL-6 were slightly increased after BRP treatment. Levels of IL-4, IL-10 and TGF-β were also reduced by BRP. BRP significantly reduced the up-regulation promoted by LPS of transcription of genes in inflammatory signaling (Pdk1, Pak1, Nfkb1, Mtcp1, Gsk3b, Fos and Elk1) and of Il1β and Il1f9 (fold-change rate > 5), which were further confirmed by the inhibition of NF-κB and MAPK signaling pathways. Furthermore, the upstream adaptor MyD88 adaptor-like (Mal), also known as TIRAP, involved in TLR2 and TLR4 signaling, was down- regulated in BRP treated LPS-activated macrophages. Given that BRP inhibited multiple signaling pathways in macrophages involved in the inflammatory process activated by LPS, our data indicated that BRP is a noteworthy food-source for the discovery of new bioactive compounds and a potential candidate to attenuate exhacerbated inflammatory diseases.

Effect of propolis on preserving human periodontal ligament cells and regulating pro‐inflammatory cytokines

“…After treatment with BP, the expression levels of inflammatory cytokines were significantly downregulated. Previous studies also showed that propolis attenuates the expression of pro‐inflammatory cytokines in different cell types, which is consistent with the current findings. Pro‐inflammatory cytokine expression levels were higher in the HBSS group than in the BP group, although the difference was not statistically significant.…”

Tumor necrosis factor-α: a key contributor to intervertebral disc degeneration

“…In rat NP cells, CCAAT/enhancer binding protein β (C/EBPβ) increases the levels of TNF-α, which is mediated by the extracellular signalregulated kinase 1/2 (ERK1/2) and p38 mitogen activated protein kinase (MAPK) pathways [19]. In monocytes and macrophages, lipopolysaccharide (LPS) induces TNF-α expression by activating early growth response factor-1 (Egr-1) [20], activator protein-1 (AP-1) [21], MAPK [22], and nuclear factor-κB (NF-κB) [23]. In neonatal rat cardiac fibroblasts, the activating transcription factor-2 (ATF-2)/c-Jun signaling pathway, but not NF-κB, is required for the up-regulation of TNF-α expression induced by angiotensin II and LPS [24].…”

Chemical Characterization and Antioxidant, Antimicrobial, and Anti-Inflammatory Activities of South Brazilian Organic Propolis

“…In contrast to European propolis, rich in flavonoids, Brazilian propolis is characterized by the presence of derivatives of prenylated cinnamic acid [8,9]. Brazilian propolis has become popular as a healthy dietary supplement, and a number of innovative propolis-containing foods and beverages have been developed, because it has been proven to prevent inflammation, heart diseases, diabetes, and cancer [10,11]. Moreover, Brazilian certified organic propolis (OP), produced in environmental conservation and reforestation areas in the states of Paraná and Santa Catarina, has attracted the attention of Europeans due to its mild flavor and absence of heavy metals and pesticides.…”