Anti-inflammatory activity of Bambusae Caulis in Taeniam through heme oxygenase-1 expression via Nrf-2 and p38 MAPK signaling in macrophages

Caspase-3 and gasdermin E mediate macrophage pyroptosis in periodontitis

BACKGROUND AND OBJECTIVES

Periodontitis is a chronic inflammatory disease linked to pyroptosis, an inflammatory cell death process. Macrophages are essential for maintaining microenvironment homeostasis, which is crucial for periodontal health. This study explores the mechanisms underlying the relationship between macrophage pyroptosis and periodontitis.

METHODS

Expression of the pyroptosis marker gasdermin E (GSDME) and the macrophage surface marker CD68 was examined by immunofluorescence double staining in healthy and periodontitis gingival tissues. In an in vitro pyroptosis model, RAW264.7 cells were irritated using Porphyromonas gingivalis-lipopolysaccharide (P. gingivalis-LPS) after treatment with either a nuclear factor kappa-B (NF-κB) agonist or inhibitor. The mRNA and protein levels of NF-κB, caspase-3, GSDME, and interleukin-1β (IL-1β) were evaluated through qRT-PCR, western blotting, and ELISA techniques.

RESULTS

GSDME and CD68 were heavily elevated in inflamed gingival tissues compared to healthy tissues and co-localized in the same region. Furthermore, exposure to P. gingivalis-LPS resulted in a significant upregulation of NF-κB, caspase-3, GSDME, and IL-1β at both the mRNA and protein levels in RAW264.7 cells. NF-κB agonist or inhibitor pretreatment enhanced or inhibited these effects.

CONCLUSIONS

GSDME-mediated macrophage pyroptosis is implicated in periodontitis. Based on in vitro experiments, P. gingivalis-LPS causes pyroptosis in RAW264.7 cells through the caspase-3/GSDME pathway. Furthermore, NF-κB regulates this pyroptotic pathway.

Involvement of polycyclic aromatic hydrocarbons and endotoxin in macrophage expression of interleukin-33 induced by exposure to particulate matter

Air pollutants are important factors that contribute to the development and/or exacerbation of allergic inflammation accompanied by asthma, but experimental evidence still needs to be collected. Interleukin 33 (IL-33) is closely involved in the onset and progression of asthma. In this study, we examined the effects of particulate matter (PM) on IL-33 expression in macrophages. PM2.5 collected in Yokohama, Japan by the cyclone device significantly induced IL-33 expression in human THP-1 macrophages, and the induction was clearly suppressed by pretreatment with the aryl hydrocarbon receptor (AhR) antagonist CH-223191 or the Toll-like receptor 4 (TLR4) antagonist TAK-242. PM2.5-induced IL-33 expression was significantly attenuated in AhR-knockout or TLR4-mutated macrophages, suggesting an important role of polycyclic aromatic hydrocarbons (PAHs) and endotoxin in IL-33 stimulation. PM samples derived from tunnel dust slightly but significantly induced IL-33 expression, while road dust PM did not affect IL-33 expression. The PAH concentration in tunnel dust was higher than that in road dust. Tunnel dust or road dust PM contained less endotoxin than PM2.5 collected in Yokohama. These data suggest that the potency of IL-33 induction could depend on the concentration of PAHs as well as endotoxin in PMs. Caution regarding PAHs and endotoxin levels in air pollutants should be taken to prevent IL-33-induced allergic inflammation.

Anti-inflammatory activity of the extracts from Rodgersia podophylla leaves through activation of Nrf2/HO-1 pathway, and inhibition of NF-κB and MAPKs pathway in mouse macrophage cells

OBJECTIVE

Recently, Rodgersia podophylla has been reported to exhibit anti-inflammatory activity. However, little is known about the potential mechanisms about its anti-inflammatory activity. We elucidated the anti-inflammatory mechanisms of leaves extracts from Rodgersia podophylla (RP-L) in RAW264.7 cells.

MATERIALS AND METHODS

LPS-induced NO was measured by Griess and mRNA of pro-inflammatory mediators was analyzed by RT-PCR. Cell viability was measured using MTT assay. The protein level was analyzed by Western blot.

RESULTS

RP-L significantly inhibited the production of the pro-inflammatory mediators such as NO, iNOS, IL-1β and IL-6 in LPS-stimulated RAW264.7 cells. RP-L increased HO-1 expression in RAW264.7 cells, and the inhibition of HO-1 by ZnPP reduced the inhibitory effect of RP-L against LPS-induced NO production in RAW264.7 cells. Inhibition of p38, ROS and GSK3β attenuated RP-L-mediated HO-1 expression. Inhibition of ROS inhibited p38 phosphorylation and GSK3β expression induced by RP-L. In addition, inhibition of GSK3β blocked RP-L-mediated p38 phosphorylation. RP-L induced nuclear accumulation of Nrf2, and inhibition of p38, ROS and GSK3β abolished RP-L-mediated nuclear accumulation of Nrf2. Furthermore, RP-L blocked LPS-induced degradation of IκB-α and nuclear accumulation of p65. RP-L also attenuated LPS-induced phosphorylation of ERK1/2 and p38. In GC/MS analysis of RP-L, pyrogallol was detected as bioactive compound for anti-inflammatory activity of RP-L. Pyrogallol was observed to activate HO-1 expression through ROS/GSK3β/p38/Nrf2/HO-1 signaling.

CONCLUSIONS

Our results suggest that RP-L exerts potential anti-inflammatory activity by activating ROS/GSK3β/p38/Nrf2/HO-1 signaling and inhibiting NF-κB and MAPK signaling in RAW264.7 cells. These findings suggest that RP-L may have great potential for the development of anti-inflammatory drug.

Involvement of Nrf2-mediated heme oxygenase-1 expression in anti-inflammatory action of chitosan oligosaccharides through MAPK activation in murine macrophages

Chitosan and its derivatives have been reported to have anti-inflammatory effects in vitro and in vivo. It is also suggested that chitosan and its derivatives could be up-regulating heme oxygenase-1 (HO-1) in different models. However, the up-regulation of HO-1 by chitosan oligosaccharides (COS) remains unexplored in regard to anti-inflammatory action in lipopolysaccharide (LPS)-stimulated murine macrophages (RAW264.7 cells). Treatment with COS induced HO-1 expression in LPS-stimulated RAW264.7 cells, whereas the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) was decreased. Pretreatment with ZnPP, a HO-1 inhibitor, reduced the COS-mediated anti-inflammatory action. HO-1 induction is mediated by activating the nuclear translocation of NF-E2-related factor 2 (Nrf2) using COS. Moreover, COS increased the phosphorylation of extracellular signal regulated kinase (ERK1/2), c-Jun N-terminal kinase/stress-activated protein kinase (JNK), and p38 MAPK. However, specific inhibitors of ERK, JNK, and p38 reduced COS-mediated nuclear translocation of Nrf2. Therefore, HO-1 induction also decreased in RAW264.7 cells. Collectively, COS exert an anti-inflammatory effect through Nrf2/MAPK-mediated HO-1 induction.

Anti-inflammatory effect of methanol extract from Erigeron Canadensis L. may be involved with upregulation of heme oxygenase-1 expression and suppression of NFκB and MAPKs activation in macrophages

BACKGROUND/OBJECTIVES

In this study, we determined the anti-inflammatory activities and the underlying molecular mechanisms of the methanol extract from Erigeron Canadensis L. (ECM) in LPS-stimulated RAW264.7 macrophage cells.

MATERIALS/METHODS

The potential anti-inflammatory properties of ECM were investigated by using RAW264.7 macrophages. We used western blot assays and real time quantitative polymerase chain reaction to detect protein and mRNA expression, respectively. Luciferase assays were performed to determine the transactivity of transcription factors.

RESULTS

ECM significantly inhibited inducible nitric oxide synthase (iNOS)-derived NO and cyclooxygenase-2 (COX-2) derived PGE2 production in LPS-stimulated RAW264.7 macrophages. These inhibitory effects of ECM were accompanied by decreases in LPS-induced nuclear translocations and transactivities of NFκB. Moreover, phosphorylation of mitogen-activated protein kinase (MAPKs) including extracellular signal-related kinase (ERK1/2), p38, and c-jun N-terminal kinase (JNK) was significantly suppressed by ECM in LPS-stimulated RAW264.7 macrophages. Further studies demonstrated that ECM by itself induced heme oxygenase-1 (HO-1) protein expression at the protein levels in dose-dependent manner. However, zinc protoporphyrin (ZnPP), a selective HO-1 inhibitor, abolished the ECM-induced suppression of NO production.

CONCLUSIONS

These results suggested that ECM-induced HO-1 expression was partly responsible for the resulting anti-inflammatory effects. These findings suggest that ECM exerts anti-inflammatory actions and help to elucidate the mechanisms underlying the potential therapeutic values of Erigeron Canadensis L.

Isoproterenol‑mediated heme oxygenase‑1 induction inhibits high mobility group box 1 protein release and protects against rat myocardial ischemia/reperfusion injury in vivo

Isoproterenol (ISO) has been reported to inhibit high mobility group box 1 (HMGB1) protein release via heme oxygenase-1 (HO-1) induction in lipopolysaccharide (LPS)-activated RAW 264.7 cells and increase the survival rate of cecal ligation and puncture (CLP)-induced septic mice. Therefore, it was examined whether ISO-mediated HO-1 induction inhibits HMGB1 release in cardiac myocytes and attenuates myocardial ischemia/reperfusion (I/R) injury in rats. Anesthetized male rats were pretreated with ISO [intraperitoneal (i.p.) injection of 10 mg/kg] prior to ischemia in the absence and/or presence of zinc protoporphyrin IX (ZnPPIX, i.p., 10 mg/kg), which is an inhibitor of HO-1, and then subjected to ischemia for 30 min followed by reperfusion for 24 h. The myocardial I/R injury and oxidative stress were assessed. In addition, the HO-1 protein and HMGB1 expression were measured by western blot analysis. ISO significantly attenuated the myocardial I/R injury, reduced oxidative stress, and induced HO-1 and reduced HMGB1 release. However, all these effects caused by ISO were significantly reversed in the presence of ZnPPIX. These results suggested that ISO has a pivotal role in the protective effects on myocardial I/R injury. This protection mechanism is possibly due to the inhibition of HMGB1 release via the induction of HO-1.

Aqueous extract of Bambusae Caulis in Taeniam inhibits PMA-induced tumor cell invasion and pulmonary metastasis: suppression of NF-κB activation through ROS signaling

Bamboo shavings (Bambusae Caulis in Taeniam, BCT) are widely used as a traditional Chinese medicine to control hypertension and cardiovascular disease, and to alleviate fever, vomiting, and diarrhea. It has been demonstrated that BCT reduces ovalbumin-induced airway inflammation by regulating pro-inflammatory cytokines, and decreases tumor growth in tumor-bearing mice. However, the effects of BCT on the metastatic potential of malignant cancer cells and the detailed mechanism of its anti-metastatic activity have not been examined previously. In this study, we investigated whether an aqueous extract of BCT (AE-BCT) reduces the metastatic potential of HT1080 cells, and elucidated the underlying anti-metastatic mechanism. In addition, we examined whether AE-BCT administration inhibits pulmonary metastasis of intravenously injected B16F10 cells in C57BL/6J mice. AE-BCT (50–250 µg/ml) dose-dependently suppressed colony-forming activity under anchorage-dependent and -independent growth conditions. Pretreatment with AE-BCT efficiently inhibited cell migration, invasion, and adhesion. AE-BCT also dramatically suppressed PMA-induced MMP-9 activity and expression by blocking NF-κB activation and ERK phosphorylation. Production of intracellular ROS, a key regulator of NF-κB-induced MMP-9 activity, was almost completely blocked by pretreatment with AE-BCT. Furthermore, daily oral administration of AE-BCT at doses of 50 and 100 mg/kg efficiently inhibited lung metastasis of B16F10 cells injected into the tail veins of C57BL/6J mice with no systemic toxicity. These results demonstrate that AE-BCT significantly reduced the metastatic activity of highly malignant cancer cells by suppressing MMP-9 activity via inhibition of ROS-mediated NF-κB activation. These results indicate that AE-BCT may be a safe natural product for treatment of metastatic cancer.

Dobutamine-mediated heme oxygenase-1 induction via PI3K and p38 MAPK inhibits high mobility group box 1 protein release and attenuates rat myocardial ischemia/reperfusion injury in vivo

BACKGROUND

It has been reported that the induction of heme oxygenase-1 (HO-1) mediated by β1-adrenergic receptor inhibits high mobility group box 1 protein (HMGB1) release and increases the survival rate in cecal ligation and puncture-induced septic mice. The present study aimed to investigate whether dobutamine, a selective β1-adrenergic receptor agonist, could inhibit HMGB1 release via β1-adrenergic receptor-mediated HO-1 induction and attenuate myocardial ischemia/reperfusion (I/R) injury in rats.

MATERIALS AND METHODS

Anesthetized male rats were pretreated with dobutamine (5 or 10 μg. Kg-1. min-1, intravenous) before ischemia in the absence and/or presence of LY294002 (0.3 mg/Kg), a phosphatidylinositol 3-kinase (PI3K)< inhibitor; SB203580 (1 mg/Kg), a p38 mitogen-activated-protein kinase (P38 mitogen-activated-protein kinase [p38 MAPK]) inhibitor, and zinc protoporphyrin IX ([ZnPPIX], 10 mg/Kg), a HO-1 inhibitor, respectively, and then subjected to ischemia for 30 min followed by reperfusion for 4 h. The myocardial I/R injury and oxidative stress were assessed. Likewise, the expressions of HO-1 protein, nuclear factor kappa B (NF-κB) p65, and HMGB1 were measured by Western blot analysis.

RESULTS

Dobutamine significantly and dose-dependently attenuated myocardial I/R injury, reduced oxidative stress, and caused the induction of HO-1, the reduction of NF-κB activation and HMGB1 over expression. However, all the effects caused by dobutamine were significantly reversed by the presence of LY294002, SB203580, and ZnPPIX, respectively.

CONCLUSIONS

The present study demonstrated that dobutamine mediated the induction of HO-1 by selectively stimulating β1-adrenergic receptor via PI3K and p38 MAPK, which inhibited HMGB1 release and attenuated rat myocardial I/R injury in vivo.