20-Hydroxy-3-Oxolupan-28-Oic Acid Attenuates Inflammatory Responses by Regulating PI3K⁻Akt and MAPKs Signaling Pathways in LPS-Stimulated RAW264.7 Macrophages

In Vitro Insights into the Role of 7,8-Epoxy-11-Sinulariolide Acetate Isolated from Soft Coral Sinularia siaesensis in the Potential Attenuation of Inflammation and Osteoclastogenesis

The balance between bone-resorbing osteoclasts and bone-forming osteoblasts is essential for the process of bone remodeling. Excessive osteoclast differentiation plays a pivotal role in the pathogenesis of bone diseases such as rheumatoid arthritis and osteoporosis. In the present study, we examined whether 7,8-epoxy-11-sinulariolide acetate (Esa), a marine natural product present in soft coral Sinularia siaesensis, attenuates inflammation and osteoclastogenesis in vitro. The results indicated that Esa significantly inhibited lipopolysaccharide (LPS)-induced inflammation model of RAW264.7 cells and suppressed receptor activator for nuclear factor-κB ligand (RANKL)-triggered osteoclastogenesis. Esa significantly down-regulated the protein expression of iNOS, COX-2, and TNF-α by inhibiting the NF-κB/MAPK/PI3K pathways and reducing the release of reactive oxygen species (ROS) in RAW264.7 macrophages. Besides, Esa treatment significantly inhibited osteoclast differentiation and suppressed the expression of osteoclast-specific markers such as NFATC1, MMP-9, and CTSK proteins. These findings suggest that Esa may be a potential agent for the maintenance of bone homeostasis associated with inflammation.

Heme Oxygenase 1-Mediated Anti-Inflammatory Effect of Extract from the Aerial Part of Heracleum moellendorffii Hance

In this study, the anti-inflammatory effects of a methanolic extract from the aerial part of Heracleum moellendorffii Hance (HmAPE) and its underlying mechanisms were investigated. HmAPE demonstrated a significant reduction in nitric oxide production in lipopolysaccharide (LPS)-treated murine macrophage RAW264.7 cells, and HmAPE decreased the protein and mRNA expression of inducible nitric oxide synthase. Further mechanistic studies on inflammatory signaling pathways revealed that HmAPE-mediated downregulation of inflammatory gene expressions was not associated with mitogen-activated protein kinases or nuclear factor-κB signaling pathways. However, HmAPE treatment activated nuclear factor E2-related factor 2 (Nrf2) and upregulated heme oxygenase-1 (HO-1) expression, which is known to suppress pro-inflammatory cytokine production. Additionally, treatment with a selective HO-1 inhibitor, tin protoporphyrin IX, partially reversed the effects of HmAPE in LPS-treated RAW264.7 cells, indicating that HmAPE inhibited LPS-induced NO production, at least in part, through induction of Nrf2-mediated HO-1 expression. These findings suggest that HmAPE could serve as a potential edible source with anti-inflammatory properties, and further studies are required to ascertain its anti-inflammatory efficacy in vivo.

Anti-Inflammatory Effects of Gynura procumbens on RAW264.7 Cells via Regulation of the PI3K/Akt and MAPK Signaling Pathways

Gynura procumbens is a traditional herb and food extensively cultivated in China and Southeast Asian countries. In this work, the crude extract (CE) of G. procumbens was purified with macroporous resin to obtain the refined fraction, and its anti-inflammatory activity was compared with that of CE. Moreover, the detailed mechanisms of anti-inflammatory activity were also investigated for the first time. The results indicated that CE was more effective in anti-inflammatory activity and it could reduce the secretion of NO, TNF-α, and PGE2 via decreasing the iNOS, TNF-α, and COX-2 genes transcription and related proteins translation, which were associated with the inhibition of AP-1 and NF-κB nuclear translocation and downregulation of PI3K/Akt and MAPK signaling pathways. In conclusion, the extract of G. procumbens has a promising potential in inflammation-related disorders alleviation, and these findings could provide the basis for the comprehensive utilization of G. procumbens and the new functional food development.

20-Hydroxy-3-Oxolupan-28-Oic Acid, a Minor Component From Mahonia bealei (Fort.) Carr. Leaves Alleviates Lipopolysaccharide-Induced Inflammatory in Murine Macrophages

20-Hydroxyl-3-oxolupan-28-oic acid (HOA), a minor component from Mahonia bealei (Fort.) Carr. leaves, has been found to attenuate inflammatory responses. However, the underlying molecular mechanism is still unclear. In this study, we performed a comprehensive transcriptional study to investigate genetic changes. We used RNA sequencing technology to analyses the transcriptional changes in RAW 264.7 cells in a control group, lipopolysaccharide (LPS)-induced group, and HOA-treated group. We identified 1,313 and 388 differentially expressed genes (DEGs) in the control/LPS group and LPS/HOA group, respectively. Gene Ontology (GO) classification revealed that the DEGs were mainly enriched in a series of inflammatory and immune-related processes. The results of Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses showed that the DEGs were mainly enriched in inflammatory-related pathways such as the nuclear factor-kappa B (NF-κB) signaling pathway, cytokine-cytokine receptor interaction, chemokine signaling pathway, mitogen-activated protein kinase (MAPK) pathway, and Janus kinase-signal transducer and activator of transcription proteins (JAK-STAT) signaling pathway. The results of qPCR validation revealed that dynamic changes in immune-related mRNAs such as Saa3, Bcl2l1, Mapkapk2, Ccl9, Sdc4, Ddx3x, Socs3, Prdx5, Tlr4, Lif, IL15, Tnfaip3, Tet2, Tgf-β1, and Ccl20, which were significantly upregulated in the LPS group and downregulated in the HOA group. Taken together, these results suggest that HOA may be used as a source of anti-inflammatory agents as well as a dietary complement for health promotion.

Anti-Inflammatory Activity of Extracts and Pure Compounds Derived from Plants via Modulation of Signaling Pathways, Especially PI3K/AKT in Macrophages

The plant kingdom is a source of important therapeutic agents. Therefore, in this review, we focus on natural compounds that exhibit efficient anti-inflammatory activity via modulation signaling transduction pathways in macrophage cells. Both extracts and pure chemicals from different species and parts of plants such as leaves, roots, flowers, barks, rhizomes, and seeds rich in secondary metabolites from various groups such as terpenes or polyphenols were included. Selected extracts and phytochemicals control macrophages biology via modulation signaling molecules including NF-κB, MAPKs, AP-1, STAT1, STAT6, IRF-4, IRF-5, PPARγ, KLF4 and especially PI3K/AKT. Macrophages are important immune effector cells that take part in antigen presentation, phagocytosis, and immunomodulation. The M1 and M2 phenotypes are related to the production of pro- and anti-inflammatory agents, respectively. The successful resolution of inflammation mediated by M2, or failed resolution mediated by M1, may lead to tissue repair or chronic inflammation. Chronic inflammation is strictly related to several disorders. Thus, compounds of plant origin targeting inflammatory response may constitute promising therapeutic strategies.

Synergistic anti-inflammatory effects of silibinin and thymol combination on LPS-induced RAW264.7 cells by inhibition of NF-κB and MAPK activation

BACKGROUND

Combination drug therapy has become an effective strategy for inflammation control. The anti‑inflammatory capacities of silibinin and thymol have each been investigated on its own, but little is known about the synergistic anti-inflammatory effects of these two compounds.

PURPOSE

This study aims to investigate the synergistic anti-inflammatory effects of silibinin and thymol when administered in combination to lipopolysaccharide (LPS)-induced RAW264.7 cells.

METHODS

RAW264.7 cells were pre-treated with silibinin and thymol individually or in combination for 2 h before LPS stimulation. Cell viability was detected by the MTT assay. Nitric oxide (NO) production was measured by Griess reagent. Reactive oxygen species (ROS) was evaluated by 2',7'-dichlorofluorescein-diacetate. ELISA was used to detect tumour necrosis factor-α (TNF-α), and interleukin-6 (IL-6). Western blot was performed to analyse the protein expression of LPS-induced RAW264.7 cells.

RESULTS

We observed a synergistic anti-inflammatory effect of silibinin and thymol when administered in combination to LPS-induced RAW264.7 cells. Silibinin combined with thymol (40 μM and 120 μM respectively, with the molar ratio 1:3) had more potent effects on the inhibition of NO, TNF-α, and IL-6 than those exerted by individual administration of these compounds in LPS-induced RAW264.7 cells. The combination of silibinin and thymol (40 μM and 120 μM respectively, with the molar ratio 1:3) strongly inhibited ROS and cyclooxygenase-2 (COX-2). More importantly, the combination of silibinin and thymol (40 μM and 120 μM respectively, with the molar ratio 1:3) was also successful in inhibiting nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) activities. Our results suggest that the synergistic anti-inflammatory effects of silibinin with thymol were associated with the inhibition of NF-κB and MAPK signalling pathways.

CONCLUSION

The combination of silibinin and thymol (40 μM and 120 μM, respectively, with the molar ratio 1:3) could inhibit inflammation by suppressing NF-κB and MAPK signalling pathways in LPS-induced RAW264.7 cells.

Leocarpinolide B attenuates LPS-induced inflammation on RAW264.7 macrophages by mediating NF-κB and Nrf2 pathways

Macrophages-mediated inflammation is involved in the regulation of rheumatoid arthritis (RA). Sigesbeckiae Herba (SH) has been traditionally used for rheumatism. However, the bioactive ingredients of SH are still unclear. Recently, we isolated a compound (Leocarpinolide B, LB) from SH and identified its potent anti-inflammatory and antioxidant effects on RAW264.7 macrophages for the first time. LB effectively inhibited excessive production of nitric oxide (NO), prostaglandin E2 (PGE₂), cytokines (IL-6, TNF-α and MCP-1), and the expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthases (iNOS) in lipopolysaccharide (LPS)-induced RAW264.7 cells. LB blocked the degradation of inhibitor of kappa B (IκBα) and translocation of nuclear factor kappa B (NF-κB) p65. Additionally, LB reduced the intracellular reactive oxygen species, and increased the expression of heme oxygenase-1 (HO-1) and the translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) in the presence or absence of LPS. The results suggested that LB might be one of the bioactive components of SH, and be potential for the treatment of RA and valuable to be further investigated.

Deciphering the Pharmacological Mechanisms of the Huayu-Qiangshen-Tongbi Formula Through Integrating Network Pharmacology and In Vitro Pharmacological Investigation

Rheumatoid arthritis is a chronic inflammatory autoimmune disease, causing articular and extra-articular dysfunctions among patients, and it could result in irreversible joint damages or disability if untreated. A traditional Chinese medicine formula, Huayu-Qiangshen-Tongbi (HT) formula, has been observed successful in controlling rheumatoid arthritis progression in traditional Chinese medicine clinics. In this study, we conducted a systematic analysis of the HT formula with a purpose of proposing for its potential mechanism of action using network pharmacological methods. The potential targets of the formula were collected and screened according to the topological features of their protein–protein interaction network, and we subsequently validated our prediction results through in vitro experiments. We proposed that the HT formula could interfere with the bone metabolism and the inflammatory pathways of the body. The experimental validation results indicated that HT formula could exhibit anti-inflammatory effects by regulating several signaling pathways specifically the Toll-like receptor signaling pathway, phosphoinositide-3-kinase–Akt signaling pathway, hypoxia-inducible factor 1 signaling pathway, mitogen-activated protein kinase signaling pathway and activator protein 1 signaling pathway.