Epimagnolin A inhibits IL-6 production by inhibiting p38/NF-κB and AP-1 signaling pathways in PMA-stimulated THP-1 cells

Anti-inflammatory effects of α-humulene on the release of pro-inflammatory cytokines in lipopolysaccharide-induced THP-1 cells

While acute inflammation is an essential physical response to harmful external influences, the transition to chronic inflammation is problematic and associated with the development and worsening of many deadly diseases. Until now, established pharmaceutical agents have had many side effects when used for long periods. In this study, a possible anti-inflammatory effect of the sesquiterpene α-humulene on lipopolysaccharide (LPS) induction was tested. Herein, human THP-1-derived macrophages were used and their pro-inflammatory interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), and interleukin-1β (IL-1β) cytokine release was measured by means of enzyme-linked immunosorbent assay. A dose-dependent effect of α-humulene on IL-6 release was observed at 0.5 and 100 µM α-humulene, with a maximum IL-6 inhibition of 60% compared to the LPS reference value after the addition of 100 µM α-humulene. TNF-α as well as IL-1β cytokine concentrations were not reduced by the addition of 0.5 and 100 µM α-humulene. This study suggests that α-humulene has potential as a promising natural alternative to established pharmaceuticals for the treatment of elevated IL-6 levels and chronic inflammation in humans.

Critical roles of PU.1/cathepsin S activation in regulating inflammatory responses of macrophages in periodontitis

OBJECTIVE

To determine the critical roles of PU.1/cathepsin S activation in regulating inflammatory responses of macrophages during periodontitis.

BACKGROUND

Cathepsin S (CatS) is a cysteine protease and exerts important roles in the immune response. Elevated CatS has been found in the gingival tissues of periodontitis patients and is involved in alveolar bone destruction. However, the underlying mechanism of CatS-driven IL-6 production in periodontitis remains unclear.

METHODS

Western blot was applied to measure mature cathepsin S(mCatS) and IL-6 expression in gingival tissues from periodontitis patients and RAW264.7 cells exposed to lipopolysaccharide from Porphyromonas gingivalis (P.g. LPS). Immunofluorescence was applied to confirm the localization of PU.1, and CatS in the gingival tissues of periodontitis patients. ELISA was performed to determine IL-6 production by the P.g. LPS-exposed RAW264.7 cells. Knockdown by shRNA was used to determine the effects of PU.1 on p38/ nuclear factor (NF)-κB activation, mCatS expression and IL-6 production in RAW264.7 cells.

RESULTS

The expressions mCatS and IL-6 were significantly upregulated in gingival macrophages. In cultured RAW264.7 cells, increased mCatS and IL-6 protein paralleled the activation of p38 and NF-κB after exposure to P.g. LPS. CatS knockdown by shRNA significantly decreased P.g. LPS-induced IL-6 expression and p38/NF-κB activation. PU.1 was significantly increased in P.g. LPS-exposed RAW264.7 cells, and PU.1 knockdown dramatically abolished the P.g. LPS-induced upregulation of mCatS and IL-6 and the activation of p38 and NF-κB. Furthermore, PU.1 and CatS colocalized in macrophages within the gingival tissues of periodontitis patients.

CONCLUSION

PU.1-dependent CatS drives IL-6 production in macrophages by activating p38 and NF-κB in periodontitis.

Asiatic Acid Attenuates Inflammation Induced by Salmonella via Upregulating LncRNA TVX1 in Microglia

Salmonella typhimurium (S.T) induces damage to the central nervous system; however, the role of Asiatic acid (AA) in this is still unknown. Microglia play a role as macrophages to recognize the invaded pathogenic microbes in the brain. The aim of this study was to investigate the protective effect and mechanism of AA on the central nervous system through an in vitro model of S.T infection in microglia. We pre-treated microglia with AA before S.T infection and explored the anti-infection mechanism of AA by sequencing, quantitative reverse transcription PCR (RT-qPCR), and Western blotting. Long non-coding RNA (lncRNA) sequencing demonstrated that inflammation is a major factor in S.T infection of microglia. RT-qPCR data demonstrated that AA inhibited S.T-induced increases in the mRNA levels of the pro-inflammatory factors interleukin (IL)-1β, IL-6, and IL-18. Western blotting demonstrated that AA inhibited S.T-induced activation of the nuclear factor (NF)-κB pathway and activation of the NLR family, pyrin domain-containing 3 (NLRP3) inflammasome. Expression of the lncRNA TVX1 in microglia was decreased by S.T infection and increased by pretreatment with AA. Inhibition of TVX1 expression reversed the anti-inflammatory effect of AA, and overexpression of TVX1 in microglia suppressed S.T-induced inflammation. In conclusion, AA attenuated S.T-induced microglial inflammation by upregulating the expression of the lncRNA TVX1.

Tumor-associated macrophage derived IL-6 enriches cancer stem cell population and promotes breast tumor progression via Stat-3 pathway

BACKGROUND

Cancer stem cells (CSCs) play crucial role in tumor progression, drug resistance and relapse in various cancers. CSC niche is comprised of various stromal cell types including Tumor-associated macrophages (TAMs). Extrinsic ques derived from these cells help in maintenance of CSC phenotype. TAMs have versatile roles in tumor progression however their function in enrichment of CSC is poorly explored.

METHODS

Mouse macrophages (RAW264.7) cells were activated by interaction with conditioned media (CM) of murine breast cancer cells (4T1) into TAMs and the effect of activated macrophage (TAM) derived factors was examined on enrichment of cancer stem cells (CSCs) and tumor growth using in vitro and in vivo models.

RESULTS

In this study, we report that macrophages upon interaction with breast cancer cells activate tumor promoting function and exhibit differential expression of various proteins as shown by secretome analysis using proteomics studies. Based on secretome data, we found that Interleukin-6 (IL-6) is one of the up-regulated genes expressed in activated macrophages. Further, we confirm that TAMs produce high levels of IL-6 and breast cancer cell derived factors induce IL-6 production in activated macrophages via p38-MAPK pathway. Furthermore, we demonstrate that tumor activated macrophages induce enrichment of CSCs and expression of CSC specific transcription factors such as Sox-2, Oct-3/4 and Nanog in breast cancer cells. We further prove that TAM derived IL-6 plays a key role in TAM mediated CSC enrichment through activation of Signal transducer and activator of transcription 3 (STAT-3) signaling. TAM derived IL-6 influences breast cancer cell migration and angiogenesis. Moreover, our in vivo findings indicated that TAM derived IL-6 induces CSC population and resulting tumor growth in breast cancer.

CONCLUSION

These finding provide evidence that TAM derived IL-6 plays a major role in CSC enrichment and tumor progression in breast cancer and IL-6 and its regulated signalling network may act as potential therapeutic target for management of breast cancer.

The DPA-derivative 11S, 17S-dihydroxy 7,9,13,15,19 (Z,E,Z,E,Z)-docosapentaenoic acid inhibits IL-6 production by inhibiting ROS production and ERK/NF-κB pathway in keratinocytes HaCaT stimulated with a fine dust PM10

11 S, 17S-dihydroxy 7,9,13,15,19 (Z,E,Z,E,Z)-docosapentaenoic acid (DoPE) is a derivative of docosapentaenoic acid, a specialized pro-resolving mediator of inflammation such as lipoxins, resolvins, maresins, and protectins. PM₁₀ is a fine dust particle that induces oxidative stress, DNA damage, inflammation, aging, and cancer. The anti-inflammatory mechanism of DoPE, however, has not yet been elucidated. In these studies, we investigated whether DoPE has anti-inflammatory effects in human keratinocyte HaCaT cells. We demonstrated that DoPE suppressed PM₁₀-induced expressions of IL-6 mRNA and protein in human HaCaT keratinocytes. We also investigated the modulating effects of DoPE on reactive oxygen species (ROS) and mitogen-activated protein kinase (MAPK). ROS production, extracellular signal regulated kinase (ERK) phosphorylation, and translocation of nuclear factor-kappa B (NF-kB) p65 and NF-kB activity were suppressed by DoPE in PM₁₀-stimulated HaCaT cells. Collectively, our results demonstrated that DoPE inhibited IL-6 expression by reducing ROS generation, suppressing ERK phosphorylation, and inhibiting translocation of NF-kB p65 and NF-kB activity in PM₁₀-stimulated HaCaT cells, suggesting that DoPE can be useful for the resolution of the inflammation caused by IL-6.

Effects of 3'-isovaleryl-4'-senecioylkhellactone from Peucedanum japonicum Thunberg on PMA-Stimulated Inflammatory Response in A549 Human Lung Epithelial Cells

Peucedanum japonicum Thunberg (PJT) has been used in traditional medicine to treat colds, coughs, fevers, and other inflammatory diseases. The goal of this study was to investigate whether 3'-isovaleryl-4'-senecioylkhellactone (IVSK) from PJT has anti-inflammatory effects on lung epithelial cells. The anti-inflammatory effects of IVSK were evaluated using phorbol 12-myristate 13-acetate (PMA)-stimulated A549 cells and regular human lung epithelial cells as a reference. IVSK reduced the secretion of the inflammatory mediators interleukin (IL)-8 and monocyte chemoattractant protein-1 (MCP-1), and the mRNA expression of IL-6, IL-8, MCP-1, and IL-1β. Additionally, it inhibited the phosphorylation of IκB kinase (IKK), p65, Iκ-Bα, and mitogen-activated protein kinases (MAPKs) p38, JNK, and ERK in A549 cells stimulated with PMA. Moreover, the binding affinity of activator protein-1 (AP-1) and nuclear factor-κB (NF-κB) was significantly reduced in the luciferase assay, while nuclear translocation was markedly inhibited by IVSK in the immunocytochemistry. These findings indicate that IVSK can protect against inflammation through the AP-1 and NF-κB pathway and could possibly be used as a lead compound for the treatment of inflammatory lung diseases.

7S,15R-Dihydroxy-16S,17S-Epoxy-Docosapentaenoic Acid, a Novel DHA Epoxy Derivative, Inhibits Colorectal Cancer Stemness through Repolarization of Tumor-Associated Macrophage Functions and the ROS/STAT3 Signaling Pathway

Colorectal cancer is a highly malignant cancer that is inherently resistant to many chemotherapeutic drugs owing to the complicated tumor-supportive microenvironment (TME). Tumor-associated macrophages (TAM) are known to mediate colorectal cancer metastasis and relapse and are therefore a promising therapeutic target. In the current study, we first confirmed the anti-inflammatory effect of 7S,15R-dihydroxy-16S,17S-epoxy-docosapentaenoic acid (diHEP-DPA), a novel DHA dihydroxy derivative synthesized in our previous work. We found that diHEP-DPA significantly reduced lipopolysaccharide (LPS)-induced inflammatory cytokines secretion of THP1 macrophages, IL-6, and TNF-α. As expected, diHEP-DPA also modulated TAM polarization, as evidenced by decreased gene and protein expression of the TAM markers, CD206, CD163, VEGF, and TGF-β1. During the polarization process, diHEP-DPA treatment decreased the concentration of TGF-β1, IL-1β, IL-6, and TNF-α in culture supernatants via inhibiting the NF-κB pathway. Moreover, diHEP-DPA blocked immunosuppression by reducing the expression of SIRPα in TAMs and CD47 in colorectal cancer cells. Knowing that an inflammatory TME largely serves to support epithelial-mesenchymal transition (EMT) and cancer stemness, we tested whether diHEP-DPA acted through polarization of TAMs to regulate these processes. The intraperitoneally injected diHEP-DPA inhibited tumor growth when administered alone or in combination with 5-fluorouracil (5-FU) chemotherapy in vivo. We further found that diHEP-DPA effectively reversed TAM-conditioned medium (TCCM)-induced EMT and enhanced colorectal cancer stemness, as evidenced by its inhibition of colorectal cancer cell migration, invasion and expression of EMT markers, as well as cancer cell tumorspheres formation, without damaging colorectal cancer cells. DiHEP-DPA reduced the population of aldehyde dehydrogenase (ALDH)-positive cells and expression of colorectal stemness marker proteins (CD133, CD44, and Sox2) by modulating TAM polarization. Additionally, diHEP-DPA directly inhibited cancer stemness by inducing the production of reactive oxygen species (ROS), which, in turn, reduced the phosphorylation of nuclear signal transducer and activator of transcription 3 (STAT3). These data collectively suggest that diHEP-DPA has the potential for development as an anticancer agent against colorectal cancer.

Psoralen inhibits the inflammatory response and mucus production in allergic rhinitis by inhibiting the activator protein 1 pathway and the downstream expression of cystatin‑SN

Psoralen (PSO) exerts anti-inflammatory pharmacological effects and plays an important role in a variety of inflammatory diseases. However, the effects of PSO with allergic rhinitis (AR) are yet to be reported. In the present study, an in vitro AR model was generated by inducing JME/CF15 human nasal epithelial cells with IL-13, after which MTT was used to assess the cytotoxicity of PSO. The expression levels of inflammatory cytokines (granulocyte-macrophage colony-stimulating factor and Eotaxin) were determined by ELISA. Furthermore, the expression of inflammatory IL-6 and −8, as well as mucin 5AC, was assessed by reverse transcription-quantitative PCR and western blotting, and cellular reactive oxygen species were detected using a 2′,7′-dichlorodihydrofluorescein diacetate fluorescent probe. Western blotting was also used to detect the expression and phosphorylation of c-Fos and c-Jun in the activator protein 1 (AP-1) pathway, as well as the expression of cystatin-SN (CST1). PSO inhibited the inflammatory response and mucus production in IL-13-induced JME/CF15 cells. Furthermore, the levels of c-Fos and c-Jun phosphorylation in the AP-1 pathway were decreased in IL-13-induced JME/CF15 cells following PSO treatment. The expression of pathway proteins was activated by the addition of PMA, an AP-1 pathway activator, which concurrently reversed the inhibitory effects of PSO on the inflammatory response and mucus formation. The addition of an AP-1 inhibitor (SP600125) further inhibited pathway activity, and IL-13-induced inflammation and mucus formation was restored. In conclusion, PSO regulates the expression of CST1 by inhibiting the AP-1 pathway, thus suppressing the IL-13-induced inflammatory response and mucus production in nasal mucosal epithelial cells.

Fargesin ameliorates osteoarthritis via macrophage reprogramming by downregulating MAPK and NF-κB pathways

Background

To investigate the role and regulatory mechanisms of fargesin, one of the main components of Magnolia fargesii, in macrophage reprogramming and crosstalk across cartilage and synovium during osteoarthritis (OA) development.

Methods

Ten-week-old male C57BL/6 mice were randomized and assigned to vehicle, collagenase-induced OA (CIOA), or CIOA with intra-articular fargesin treatment groups. Articular cartilage degeneration was evaluated using the Osteoarthritis Research Society International (OARSI) score. Immunostaining and western blot analyses were conducted to detect relative protein. Raw264.7 cells were treated with LPS or IL-4 to investigate the role of polarized macrophages. ADTC5 cells were treated with IL-1β and conditioned medium was collected to investigate the crosstalk between chondrocytes and macrophages.

Results

Fargesin attenuated articular cartilage degeneration and synovitis, resulting in substantially lower Osteoarthritis Research Society International (OARSI) and synovitis scores. In particular, significantly increased M2 polarization and decreased M1 polarization in synovial macrophages were found in fargesin-treated CIOA mice compared to controls. This was accompanied by downregulation of IL-6 and IL-1β and upregulation of IL-10 in serum. Conditioned medium (CM) from M1 macrophages treated with fargesin reduced the expression of matrix metalloproteinase-13, RUNX2, and type X collagen and increased Col2a1 and SOX9 in OA chondrocytes, but fargesin alone did not affect chondrocyte catabolic processes. Moreover, fargesin exerted protective effects by suppressing p38/ERK MAPK and p65/NF-κB signaling.

Conclusions

This study showed that fargesin switched the polarized phenotypes of macrophages from M1 to M2 subtypes and prevented cartilage degeneration partially by downregulating p38/ERK MAPK and p65/NF-κB signaling. Targeting macrophage reprogramming or blocking the crosstalk between macrophages and chondrocytes in early OA may be an effective preventive strategy.

MicroRNA-18b-5p Downregulation Favors Mycobacterium tuberculosis Clearance in Macrophages via HIF-1α by Promoting an Inflammatory Response

The modulation of the interaction between macrophages and Mycobacterium tuberculosis (M.tb) through microRNA during M.tb infection is increasingly capturing the attention of researchers. However, the potential role of microRNA-18b-5p (miR-18b) is not elucidated yet. In this study, miR-18b was found to be downregulated in M.tb-infected macrophage cell lines (THP-1 and RAW264.7) in time- and dose-dependent manners. Furthermore, when the miR-18b mimic and inhibitor and small interfering RNA hypoxia-inducible factor 1α (si-HIF-1α) were transfected into the macrophages separately or in combination, it was found that miR-18b targeted hypoxia-inducible factor 1α (HIF-1α). During M.tb infection, the decrease in the expression of miR-18b facilitated HIF-1α expression, which led to the increased production of pro-inflammatory cytokines, such as IL-6, resulting in decreased bacterial survival in the host cells. Moreover, the phosphorylation of p38 MAPK and NF-κB p65 was activated by the miR-18b inhibitor. Our findings expand the current understanding of the M.tb-cell interaction mechanism and provide a potential target to control M.tb infection.

In vitro inhibition effects of hepatitis B virus by dandelion and taraxasterol

Hepatitis B virus (HBV) causes hepatitis, which progresses to fatal liver diseases and remains a global health problem. Current treatments for chronic hepatitis B are unable to cure hepatitis. Thus, new antiviral drugs must be developed. In this study, the viral inhibition effects of dandelion and taraxasterol were assessed in HepG2.2.15 cell line. Taraxacum officinale F.H.Wigg. (compositae) with English name dandelion is used as a traditional herb for liver disorders and as a common antiviral agent. Taraxasterol is one of the active compounds of dandelion. The secretion of HBV DNA and HBV surface antigen (HBsAg) and HBeAg was detected using fluorescence quantitative PCR (qPCR) and ELISA, respectively. Intracellular HBsAg was detected by immunofluorescence. In order to demonstrate the potential mechanism of anti-viral activity, the expression levels of host factors polypyrimidine tract binding protein 1 (PTBP1) and sirtuin 1 (SIRT1) were detected with Western blotting and qPCR. Dandelion and taraxasterol effectively reduced the secretion of HBsAg, HBeAg and the HBV DNA in cell supernatants, and significantly reduced the intracellular HBsAg as indicated by immunofluorescence results. Taraxasterol may be one of the main effective components of dandelion. It significantly decreased the protein expression levels of PTBP1 and SIRT1. The present study revealed that dandelion and its component taraxasterol could inhibit HBV and may be a potential anti-HBV drug, whose potential targets were the host factors PTBP1 and SIRT1.

Lirioresinol B dimethyl ether inhibits NF-κB and COX-2 and activates IκBα expression in CCl4-induced hepatic fibrosis

Background

Inflammation is one of the key components in the initiation and progression of hepatic diseases. If not treated, inflammation may cause cell dysplasia, and ultimately cancer. In the current study, we investigated the anti-inflammatory and anti-cancer activities of plant isolated compound Lirioresinol B Dimethyl Ether (LBDE) extracted from the seeds of Magnolia fargesii CHENG (Magnoliaceae) against HepG2 cells as well as in BALB/C male mice.

Methods

We assessed the antioxidant and anti-proliferative effects of plant compounds using DPPH assay and HepG2 cell lines. Carbon tetrachloride (CCl₄) and Diethylnitrosamine (DEN) were used to induce liver cell dysplasia followed by hepatocellular carcinoma (HCC) in BALB/C male mice for 12 weeks. We investigated the underlying mechanism by using histopathology and immunoblot experiments.

Results

Intraperitoneal injection of LBDE (50 mg/kg body weight/day) inhibited CCl₄-induced HCC. Free radical scavenging assay shows the strong anti-oxidant activity of LBDE. Western blot results show that LBDE down-regulated nuclear factor kappa B (NFκB) and cyclooxygenase (COX-2) by preventing the phosphorylation of I kappa B alpha (IκBα) in CCl₄ treated group. LBDE also improved liver function by decreasing Alkaline Phosphatase (ALP), aspartate aminotransferase (AST) and Alanine Aminotransferase (ALT) levels. Histopathology results revealed that LBDE decreased granulomas and express normal morphology of hepatocytes.

Conclusions

These preliminary results show that LBDE has the potential to inhibit CCl₄-induced liver cell dysplasia and prevents cancer development by regulating NFκB/COX-2 activation.

Chemical composition of tetraploid Gynostemma pentaphyllum gypenosides and their suppression on inflammatory response by NF-κB/MAPKs/AP-1 signaling pathways

The chemical composition and anti-inflammatory activity of gypenosides isolated from tetraploid Gynostemma pentaphyllum (GP) leaves were investigated. The gypenosides accounted for 7.43 mg/g of the tested GP sample, which were composed of four major saponins including isomers of gypenoside 1 and 2 (C47H76O18), 3 (C47H76O17), and 4 (C46H74O17). Pretreatment of gypenosides reduced mRNA expressions of the proinflammatory mediators in LPS-stimulated RAW264.7 macrophage cells, such as IL-6, IL-1β, COX-2, and TNF-α in a dose-dependent manner. The secreted protein levels of IL-6 and TNF-α, and NO production were also decreased by gypenosides within the concentration range of 50-200 μg/ml. Moreover, the mechanism studies demonstrated that gypenosides (200 μg/ml) treatment significantly inhibited the nuclear translocation of nuclear factor-κB and activator protein 1 (c-Fos and c-Jun) through down-regulating the phosphorylation of their upstream IκB kinase and mitogen-activated protein kinases (MAPKs), especially that of c-Jun N-terminal kinase and extracellular regulated protein kinase(JNK and ERK), but not that of the p38 MAPK. These results suggested that the gypenosides might have potential anti-inflammatory effect and use for improving human health.

Resolvin D5, a Lipid Mediator, Inhibits Production of Interleukin-6 and CCL5 Via the ERK-NF-κB Signaling Pathway in Lipopolysaccharide-Stimulated THP-1 Cells

One of the omega-3 essential fatty acids, docosahexaenoic acid (DHA), is a significant constituent of the cell membrane and the precursor of several potent lipid mediators. These mediators are considered to be important in preventing or treating several diseases. Resolvin D5, an oxidized lipid mediator derived from DHA, has been known to exert anti-inflammatory effects. However, the detailed mechanism underlying these effects has not yet been elucidated in human monocytic THP-1 cells. In the present study, we investigated the effects of resolvin D5 on inflammation-related signaling pathways, including the extracellular signal-regulated kinase (ERK)-nuclear factor (NF)-κB signaling pathway. Resolvin D5 downregulated the production of interleukin (IL)-6 and chemokine (C-C motif) ligand 5 (CCL5). Additionally, these inhibitory effects were found to be modulated by mitogen-activated protein kinase (MAPK) and NF-κB in lipopolysaccharide (LPS)-treated THP-1 cells. Resolvin D5 inhibited the LPS-stimulated phosphorylation of ERK and translocation of p65 and p50 into the nucleus, resulting in the inhibition of IL-6 and CCL5 production. These results revealed that resolvin D5 exerts anti-inflammatory effects in LPS-treated THP-1 cells by regulating the phosphorylation of ERK and nuclear translocation of NF-kappaB.