Costunolide improved dextran sulfate sodium-induced acute ulcerative colitis in mice through NF-κB, STAT1/3, and Akt signaling pathways.

Costunolide (CTL) is the major sesquiterpene lactone from Radix Aucklandiae, which is widely used on the treatment of gastrointestinal diseases. However, the therapeutic effect of costunolide in ulcerative colitis (UC) is still unknown. Herein, we sought to evaluate the therapeutic effects and underlying mechanisms of costunolide on UC. ICR mice were intraperitoneally administered with costunolide (10 mg/kg) for 10 days. Beginning on the 4th day of drug administration, acute colitis was induced by feeding 4% dextran sulfate sodium (DSS) for additional 7 days. Costunolide markedly attenuated DSS-induced body weight loss, colonic shortening, elevation in disease activity index, and pathological damage of colon, and decreased the number of CD4+ T cells in colon tissues. Furthermore, costunolide significantly inhibited myeloperoxidase (MPO) activity and nitric oxide (NO) level in colon tissues in DSS-exposed mice. Meanwhile, costunolide also suppressed DSS-induced expression of induced nitric oxide synthase (iNOS), interleukin-1ß (IL-1ß), IL-6, tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ) in both mRNA and protein levels. Mechanistically, costunolide repressed the phosphorylation of nuclear factor kappa-B (NF-κB) p65 and degradation of inhibitor of NF-κB (IκB), as well as the excessive activation of signal transducers and activators of transcription 1/3 (STAT1/3) and serine/threonine protein kinase Akt (Akt) in colon tissues in DSS-challenged mice. These findings successfully demonstrated that costunolide ameliorated DSS-induced murine acute colitis by suppressing inflammation through inactivation of NF-κB, STAT1/3, and Akt pathways. These results also suggested that costunolide may be a potential therapeutic agent for the treatment of acute UC.

Asaronic Acid Attenuates Macrophage Activation toward M1 Phenotype through Inhibition of NF-κB Pathway and JAK-STAT Signaling in Glucose-Loaded Murine Macrophages.

Macrophage polarization has been implicated in the pathogenesis of obesity and type 2 diabetes, which are recognized as chronic proinflammatory diseases. This study investigated that high level of glucose, similar to lipopolysaccharide (LPS), activated macrophages toward M1 phenotypes and 1-20 µM asaronic acid (AA) counteracted diabetic macrophage activation. AA reduced the LPS-promoted secretion of proinflammatory interleukin (IL)-6 and monocyte chemoattractant protein-1. The LPS markedly elevated the macrophage induction of the M1 markers of Toll-like receptor 4 (TLR4), CD36, and CD68, which was attenuated by AA. Also, the LPS significantly enhanced the nuclear factor (NF)-κB transactivation, signal transducers, and activators of transcription 1 (STAT1)/STAT3 activation and suppressor of cytokine signaling 3 (SOCS3) induction in macrophages. However, AA highly suppressed the aforementioned effects of LPS. Glucose-stimulated macrophages expressed advanced glycation end products (AGEs) and receptor for AGE (RAGE). Administration of 20 µM AA to macrophages partly but significantly attenuated such effects (1.65 ± 0.12 vs 0.95 ± 0.25 times glucose control for AGE; 2.33 ± 0.31 vs 1.40 ± 0.22 times glucose control for RAGE). Furthermore, glucose enhanced the macrophage induction of TLR4 and inducible nitric oxide synthase and IL-6 production, while it demoted the production of anti-inflammatory arginase-1 and IL-10. In contrast, AA reversed the induction of these markers in glucose-loaded macrophages. AA dose-dependently and significantly encumbered NF-κB transactivation, Janus kinase 2 (JAK2) and STAT1/STAT3 activation, and SOCS3 induction upregulated in glucose-supplemented macrophages. These results demonstrated for the first time that AA may limit diabetic macrophage activation toward the M1 phenotype through the inhibition of TLR4-/IL-6-mediated NF-κB/JAK2-STAT signaling entailing AGE-RAGE interaction.

Tumor suppressor TET2 promotes cancer immunity and immunotherapy efficacy.

Loss-of-function mutations in genes encoding TET DNA dioxygenase occur frequently in hematopoietic malignancy, but rarely in solid tumors which instead commonly have reduced activity. The impact of decreased TET activity in solid tumors is not known. Here we show that TET2 mediates interferon γ (IFNγ)-JAK-STAT signaling pathway to control chemokine and PD-L1 expression, lymphocyte infiltration and cancer immunity. IFNγ stimulated STAT1 to bind TET2 and recruit TET2 to hydroxymethylate chemokine and PD-L1 genes. Reduced TET activity was associated with decreased TH1-type chemokines and tumor-infiltrating lymphocytes (TILs) and the progression of human colon cancer. Deletion of Tet2 in murine melanoma and colon tumor cells reduced chemokine expression and TILs, enabling tumors to evade anti-tumor immunity and to resist anti-PD-L1 therapy. Conversely, stimulating TET activity by systematic injection of its co-factor, ascorbate/vitamin C, increased chemokine and TILs, leading to enhanced anti-tumor immunity and anti-PD-L1 efficacy and extended lifespan of tumor-bearing mice. These results suggest an IFNγ-JAK-STAT-TET signaling pathway that mediates tumor response to anti-PD-L1/PD-1 therapy and is frequently disrupted in solid tumors. Our findings also suggest TET activity as a biomarker for predicting the efficacy and patient response to anti-PD-1/PD-L1 therapy, and stimulating TET activity as an adjuvant immunotherapy of solid tumors.

Aloin reduces inflammatory gene iNOS via inhibition activity and p-STAT-1 and NF-κB.

Aloin is the major anthraquinone glycoside obtained from the Aloe species and exhibits anti-inflammatory and anti-oxidative activities. Here, we aimed to determine the effects of aloin on heme oxygenase-1 (HO-1) induction and on the expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX) 2 in lipopolysaccharide (LPS)-activated human umbilical vein endothelial cells (HUVECs). To the end, aloin was tested whether aloin reduces iNOS protein expression and inflammatory markers (interleukin (IL)-1ß and tumor necrosis factor (TNF)-α) in LPS-treated mice lung tissue. The results indicated that aloin affected HO-1 induction and reduced LPS-activated NF-κB-luciferase activity showed to preferential inhibition of iNOS/NO and COX-2/PGE2 that was partly related to inhibition of STAT-1 phosphorylation. In particular, aloin induced translocation of Nrf2 from cytosol into the nucleus by an increased Nrf2-ARE binding activity, and reduced IL-1ß production in LPS-activated HUVECs. The reduced expression of iNOS/NO by aloin was reversed by siHO-1RNA-transfection. In LPS-treated mice, aloin significantly reduced iNOS protein in lung tissues, and TNF-α levels in the BALF. We concluded that aloin may be beneficial for treatment of lung injury.

Mahonia oiwakensis Extract and Its Bioactive Compounds Exert Anti-Inflammatory Activities and VEGF Production Through M2-Macrophagic Polarization and STAT6 Activation.

Macrophages play an indispensable role in the host immune defense. Macrophages can undergo polarization into classically (M1) and alternatively (M2) activated macrophages. M1 macrophages activate immune and inflammatory response, while M2 macrophages are involved in tissue remodeling. Mahonia oiwakensis (Mo) is a herbal medicine in Asia used for its anti-inflammatory and analgesic properties; however, the mechanism is unclear. This study analyzed the effect of Mo extracts and its effects on the polarization of both macrophage RAW264.7 cells and mouse splenic macrophages. Water (Mo-W) and EtOH extracts (Mo-E) did not change the viability of RAW264.7 cells, whereas Mo-E inhibited nitric oxide (NO) production. The major compounds, berberine and palmatine, decreased the viability and NO levels of cells. The secretion of inflammatory cytokines CXCL16, IL-6, L-selectin, MCP1, RANTES, and sTNF-R1 was downregulated, whereas the production of vascular endothelial growth factor (VEGF) was upregulated by Mo-E, berberine, and palmatine treatments. Mo-E, berberine, and palmatine stimulated the expression of macrophage CD68 and M2-type CD204 markers, decreased M1-mediated p-STAT1 and NF-κB, and increased M2-mediated p-STAT6 expression. Similar effects on M2 polarization were also observed in splenic macrophages from mice. In conclusion, Mo-E, berberine, and palmatine modulated macrophages through the suppression of M1-mediated inflammation and the recruitment of M2-mediated VEGF secretion and STAT6 expression.

Downregulated SOCS1 expression activates the JAK1/STAT1 pathway and promotes polarization of macrophages into M1 type.

Macrophage polarization is flexible, and involves in different signaling pathways and various transcription factors. Suppressor of cytokine signaling (SOCS) is an important inhibitor of cytokine signaling pathways and also a key physiological regulator for natural and acquired immunity systems. Following transfection of SOCS1 short hairpin (sh)RNA into mouse macrophage cells, reverse transcription­quantitative polymerase chain reaction demonstrated that the mRNA levels of Janus kinase (JAK)1 and signal transducer and activator of transcription (STAT)1 increased significantly. In addition, western blotting indicated that JAK1, STAT1 and p­STAT1 expression was significantly enhanced. Fludarabine can inhibit phosphorylation of STAT1 and SOCS1 expression. When fludarabine was added and SOCS1 shRNA was transfected, the inhibition of fludarabine was weakened, and p­STAT1 expression was upregulated. Flow cytometry detection indicated that, following the downregulation of SOCS1 expression, M1­type cells significantly increased, but the proportion of M2­type cells did not change significantly. Fludarabine can reduce the effect of SOCS1 shRNA on promoting M1­type cell polarization, and macrophages can polarize into both M1 and M2 phenotypes. Further ELISA results presented that, when downregulating SOCS1 expression, interleukin (IL)­4 and IL­10 expression was both downregulated, and tumor necrosis factor (TNF)­α and interferon (IFN)­Î³ expression was significantly upregulated. When adding fludarabine or injecting with the traditional Chinese medicine Xuebijing, IL­4 and IL­10 expression was both significantly upregulated, and TNF­α and IFN­Î³ expression was significantly downregulated. When adding fludarabine and downregulating SOCS1, IL­4, IL­10, TNF­α and IFN­Î³ expression presented no significant changes. The above results indicated that, when SOCS1 expression is downregulated, it will activate the JAK1/STAT1 pathway, and thereby promote the polarization of macrophages into M1 type. The findings are of great importance for understanding occurrence, development and treatment of various immune­related diseases.

Selective inhibition of JAK2/STAT1 signaling and iNOS expression mediates the anti-inflammatory effects of coniferyl aldehyde.

Urgent needs still exist for selective control of excessive inflammation. Despite the therapeutic potential of natural compounds against inflammation-associated chronic conditions, lack of specific molecular targets renders these bioactive compounds difficult for further development. Here we examined the bioactivity of coniferyl aldehyde (CA), a natural phenolic compound found in several dietary substances and medicinal plants, elucidating its efficacy both in vivo and in vitro with underlying molecular mechanisms. IFN-γ/TNF-α-stimulated human keratinocytes and lipopolysaccharide (LPS)-stimulated murine macrophages were used to examine the effect of CA in vitro and to elucidate the underlying mechanisms. In vivo models of phorbol 12-myristate 13-acetate (TPA)-induced ear edema and carrageenan (CRG)-induced paw edema were employed to investigate the topical and systemic anti-inflammatory effects of CA, respectively. CA significantly reduced nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) expression in LPS-stimulated macrophages. While nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPKs) pathways, the representative cellular pathways for iNOS induction, were not affected by CA, phosphorylation of Janus kinase 2 (JAK2) and signal Transducers and Activators of Transcription 1 (STAT1) and subsequent nuclear translocation of p-STAT1 were significantly decreased by CA. The effect of CA on JAK2-STAT1-iNOS axis was also observed in human keratinocytes stimulated with IFN-γ/TNF-α. Topical application of CA to mice produced significant protection against TPA-induced ear edema along with suppressed epidermal hyperproliferation and leucocyte infiltration. Systemic administration of CA significantly reduced CRG-induced paw edema in rats, where CRG-induced iNOS expression and STAT1 phosphorylation were decreased by CA. In summary, CA has significant anti-inflammatory properties both in vitro and in vivo, mediated by significant selective inhibition of JAK2-STAT1-iNOS signaling. CA is an attractive novel candidate for treating inflammatory diseases associated with excessive production of NO.

Potential Involvement of Type I Interferon Signaling in Immunotherapy in Seasonal Allergic Rhinitis.

Specific immunotherapy (SIT) reverses the symptoms of seasonal allergic rhinitis (SAR) in most patients. Recent studies report type I interferons shifting the balance between type I T helper cell (Th1) and type II T helper cells (Th2) towards Th2 dominance by inhibiting the differentiation of naive T cells into Th1 cells. As SIT is thought to cause a shift towards Th1 dominance, we hypothesized that SIT would alter interferon type I signaling. To test this, allergen and diluent challenged CD4+ T cells from healthy controls and patients from different time points were analyzed. The initial experiments focused on signature genes of the pathway and found complex changes following immunotherapy, which were consistent with our hypothesis. As interferon signaling involves multiple genes, expression profiling studies were performed, showing altered expression of the pathway. These findings require validation in a larger group of patients in further studies.

Curcumin and omega-3 fatty acids enhance NK cell-induced apoptosis of pancreatic cancer cells but curcumin inhibits interferon-γ production: benefits of omega-3 with curcumin against cancer.

STAT-3 and STAT-1 signaling have opposite effects in oncogenesis with STAT-3 acting as an oncogene and STAT-1 exerting anti-oncogenic activities through interferon-γ and interferon-α. The cytokine IL-6 promotes oncogenesis by stimulation of NFκB and STAT-3 signaling. Curcuminoids have bi-functional effects by blocking NFκB anti-apoptotic signaling but also blocking anti-oncogenic STAT-1 signaling and interferon-γ production. In our recent study (unpublished work [1]) in pancreatic cancer cell cultures, curcuminoids enhanced cancer cell apoptosis both directly and by potentiating natural killer (NK) cell cytotoxic function. The cytotoxic effects of curcuminoids were increased by incubation of cancer cells and NK cells in an emulsion with omega-3 fatty acids and antioxidants (Smartfish), which enhanced cancer cell apoptosis and protected NK cells against degradation. However, as also shown by others, curcuminoids blocked interferon-γ production by NK cells. The combined use of curcuminoids and omega-3 in cancer immunotherapy will require deeper understanding of their in vivo interactions with the immune system.

Luteolin sensitizes the antiproliferative effect of interferon α/ß by activation of Janus kinase/signal transducer and activator of transcription pathway signaling through protein kinase A-mediated inhibition of protein tyrosine phosphatase SHP-2 in cancer cells.

New negative regulators of interferon (IFN) signaling, preferably with tissue specificity, are needed to develop therapeutic means to enhance the efficacy of type I IFNs (IFN-α/ß) and reduce their side effects. We conducted cell-based screening for IFN signaling enhancer and discovered that luteolin, a natural flavonoid, sensitized the antiproliferative effect of IFN-α in hepatoma HepG2 cells and cervical carcinoma HeLa cells. Luteolin promoted IFN-ß-induced Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway activation by enhancing the phosphorylation of Jak1, Tyk2, and STAT1/2, thereby promoting STAT1 accumulation in the nucleus and endogenous IFN-α-regulated gene expression. Of interest, inhibition of phosphodiesterase (PDE) abolished the effect of IFN-ß and luteolin on STAT1 phosphorylation. Luteolin also increased the cAMP-degrading activity of PDE bound with type I interferon receptor 2 (IFNAR2) and decreased the intracellular cAMP level, indicating that luteolin may act on the JAK/STAT pathway via PDE. Protein kinase A (PKA) was found to negatively regulate IFN-ß-induced JAK/STAT signaling, and its inhibitory effect was counteracted by luteolin. Pull-down and immunoprecipitation assays revealed that type II PKA interacted with IFNAR2 via the receptor for activated C-kinase 1 (RACK-1), and such interaction was inhibited by luteolin. Src homology domain 2 containing tyrosine phosphatase-2 (SHP-2) was further found to mediate the inhibitory effect of PKA on the JAK/STAT pathway. These data suggest that PKA/PDE-mediated cAMP signaling, integrated by RACK-1 to IFNAR2, may negatively regulate IFN signaling through SHP-2. Inhibition of this signaling may provide a new way to sensitize the efficacy of IFN-α/ß.

Lysimachia clethroides Duby extract attenuates inflammatory response in Raw 264.7 macrophages stimulated with lipopolysaccharide and in acute lung injury mouse model.

ETHNOPHARMACOLOGICAL RELEVANCE: Lysimachia clethroides Duby (LC) is a traditional medicinal herb used to treat edema, hepatitis and inflammatory diseases in China and other Asian countries. In this study, the anti-inflammatory effects of LC extract and the mechanisms underlying were explored in both in vitro cell lines and acute lung injury (ALI) animal model of inflammation in vivo. MATERIALS AND METHODS: Lipopolysaccharide (LPS)-stimulated Raw 264.7 murine macrophages were used to study the regulatory effects of LC extract on inflammatory mediators such as nitric oxide (NO) and proinflammatory cytokine expression. Western blotting or ELISA techniques were employed to estimate protein levels. RT-PCR was used for analyzing the interferon (IFN)-ß production. LPS-induced ALI mouse model in vivo was employed to study the effect of LC extract. Further high-performance liquid chromatography (HPLC) fingerprinting technique was used to evaluate the active constituents present in LC extract, compared with reference standards. RESULTS: Pre-treatment with LC extract inhibited the LPS-stimulated NO release, interleukin (IL)-1ß and IL-6 production in Raw 264.7 cells dose dependently. LC extract inhibited the LPS-stimulated IRF3 and STAT1 phosphorylation. Further, in vivo experiments revealed that LC extract suppressed the infiltration of immune cells into the lung and proinflammatory cytokine production in broncho-alveolar lavage fluid (BALF) in the LPS-induced ALI mouse model. CONCLUSIONS: Our results indicate that LC extract attenuates LPS-stimulated inflammatory responses in macrophages via regulating the key inflammatory mechanisms, providing a scientific support for its traditional use in treating various inflammatory diseases.

Cigarette smoke increases BLT2 receptor functions in bronchial epithelial cells: in vitro and ex vivo evidence.

Leukotriene B(4) (LTB(4)) is a neutrophil chemotactic molecule with important involvement in the inflammatory responses of chronic obstructive pulmonary disease (COPD). Airway epithelium is emerging as a regulator of innate immune responses to a variety of insults including cigarette smoke, the major risk factor for COPD. In this study we have explored whether cigarette smoke extracts (CSE) or soluble mediators present in distal lung fluid samples (mini-bronchoalveolar lavages) from smokers alter the expression of the LTB(4) receptor 2 (BLT2) and peroxisome proliferator-activated receptor-α (PPAR-α) in bronchial epithelial cells. We also evaluated the effects of CSE on the expression of intercellular adhesion molecule 1 (ICAM-1) and on the binding of signal transducer and activator of transcription 1 (STAT-1) to ICAM-1 promoter as well as the adhesiveness of neutrophils to bronchial epithelial cells. CSE and mini-bronchoalveolar lavages from smokers increased BLT2 and ICAM-1 expression as well as the adhesiveness of neutrophils to bronchial epithelial cells and decreased PPAR-α expression. CSE induced the activation of STAT-1 and its binding to ICAM-1 promoter. These findings suggest that, in bronchial epithelial cells, CSE promote a prevalent induction of pro-inflammatory BLT2 receptors and activate mechanisms leading to increased neutrophil adhesion, a mechanism that contributes to airway neutrophilia and to tissue damage.

Sodium tanshinone IIA sulfonate protects mice from ConA-induced hepatitis via inhibiting NF-kappaB and IFN-gamma/STAT1 pathways.

INTRODUCTION: Sodium tanshinone IIA sulfonate (STS) is a water-soluble derivative of tanshinone IIA, the main pharmacologically active component of Salvia miltiorrhiza. The aim of this study was to investigate the effect of STS on concanavalin A (ConA)-induced hepatitis (CIH) in mice, an experimental model of immune-mediated liver injury. RESULTS: C57BL/6 mice pretreated with STS released much less alanine transaminase into plasma in response to ConA challenge and had reduced inflammatory infiltration and hepatocyte apoptosis in the liver compared with control mice pretreated with vehicle solutions. Thus, STS protected mice from CIH. In STS-pretreated mice induced with CIH, we found abrogated tumor necrosis factor-alpha and interferon (IFN)-gamma production. Moreover, mRNA expressions of IFN-inducible protein-10 and macrophage inflammatory protein-1alpha in these mice were decreased. The mechanism of anti-inflammatory effects of STS may be attributed to its modulation of crucial inflammatory signaling pathways, including NF-kappaB and IFN-gamma/STAT1. CONCLUSION: In conclusion, STS was capable of protecting mice from immune-mediated liver injury in vivo, and the protection was associated with its suppressive effect on the production of important inflammatory mediators through modulating NF-kappaB and IFN-gamma/STAT1 signaling pathways.

1,25 Dihydroxyvitamin-D3 modulates JAK-STAT pathway in IL-12/IFNgamma axis leading to Th1 response in experimental allergic encephalomyelitis.

Experimental allergic encephalomyelitis (EAE) is a Th1 cell-mediated autoimmune disease model of multiple sclerosis (MS). Vitamin D deficiency is commonly observed in MS patients and vitamin D supplements reduce the clinical symptoms of EAE and MS. Earlier studies have shown that in vivo treatment with vitamin D analogs ameliorates EAE in association with the inhibition of IL-12 production and Th1 differentiation. The mechanisms in the regulation of Th1 response by vitamin D in EAE/MS are, however, not known. We show that in vivo treatment of C57BL/6 and SJL/J mice (i.p.) with 100 ng of 1,25 dihydroxyvitamin D3, on every other day from Day 0-30, ameliorates EAE in association with the inhibition of IL-12 production and neural antigen-specific Th1 response. In vitro treatment with 1,25(OH)2D3 inhibited IFNgamma-induced tyrosine phosphorylation of STAT1, without affecting JAK2, in EOC-20 microglial cells. Treatment of activated T cells with 1,25(OH)2D3 also inhibited the IL-12-induced tyrosine phosphorylation of JAK2, TYK2, STAT3, and STAT4 in association with a decrease in T cell proliferation in vitro. These findings highlight the fact that vitamin D modulates JAK-STAT signaling pathway in IL-12/IFNgamma axis leading to Th1 differentiation and further suggest its use in the treatment of MS and other Th1 cell-mediated autoimmune diseases.