Complement C5a potentiates uric acid crystal‐induced IL‐1β production

Anaphylatoxin C5a released upon complement activation is associated with both acute and chronic inflammations such as gout. The pathogenesis of gout was identified as uric acid crystal deposition in the joints that activates inflammasome, leading to IL‐1β release. However, little is known about the interaction between complement activation and monosodium urate/uric acid (MSU) crystal‐induced inflammasome activation or IL‐1β production. Here, we report that MSU crystal‐induced proinflammatory cytokines/chemokines in human whole blood is predominantly regulated by C5a through its interaction with C5a receptor. C5a induces pro‐IL‐1β and IL‐1β production in human primary monocytes, and potentiates MSU or cholesterol crystals in IL‐1β production. This potentiation is caspase‐1 dependent and requires intracellular Ca²⁺ mobilization, K⁺ efflux, and cathepsin B activity. Our results provide insight into the role of C5a as an endogenous priming signal that is required for the initiation of uric acid crystal‐induced IL‐1β production. C5a could potentially be a therapeutic target together with IL‐1β antagonists for the treatment of complement‐dependent and inflammasome‐associated diseases.     

Role of cathepsin B in regulating migration and invasion of fibroblast‐like synoviocytes into inflamed tissue from patients with rheumatoid arthritis

Cathepsin B (CB), an important proteinase that participates in joint destruction in rheumatoid arthritis (RA), exhibits higher expression in fibroblast‐like synoviocyte (FLS) of abnormal proliferative synovial tissues. Whether and how it affects the biological behaviours of RA‐FLS, such as migration and invasion, are poorly understood. In the present study, CB expression in synovial tissues of patients with RA and ostearthritis (OA) were measured by quantitative polymerase chain reaction (qPCR) and immunohistochemistry (IHC), respectively. Stable depletion of endogenous CB was achieved by small interfering RNA (siRNA) transfection, and decrease of CB activity was acquired by using its specific inhibitor (CA074Me). The effects of CA074Me and RNA interference (RNAi) treatments on proliferation, migration, invasion, matrix metalloproteinase (MMP)‐2/‐9 expression, focal adhesion kinase (FAK) activation, and mitogen‐activated protein kinases (MAPKs) phosphorylation of FLS were analysed. In RA synovial tissues, CB was expressed at elevated levels compared with OA synovial tissues. CA074Me could inhibit invasion of FLS obtained from RA patients in an ex‐vivo invasion model. CA074Me and siRNA treatments suppressed the migration and invasion of FLS, reduced the activity, expression and mRNA level of MMP‐2, restrained the activation of FAK and reduced the expression of F‐actin. Moreover, CA074Me decreased the phosphorylation of P38 MAPK and c‐Jun N‐terminal kinase (JNK) in FLS, while siCB treatment reduced the phosphorylation of P38 but not JNK. CB substantially contributes to the invasive phenotype of FLS that leads to joint destruction in RA. This proteinase may show promise as a therapeutic target in inflammatory arthritis.     

丹酚酸B抑制氧化应激引起骨髓间质干细胞凋亡的研究

目的: 观察丹酚酸B (Sal B)对氧化应激介导骨髓间质干细胞(BMSCs)凋亡的影响并探讨其作用机制。方法: 大鼠BMSCs培养鉴定后分为5组:空白对照组、氧化应激组、低浓度Sal B＋H₂O₂组、中浓度Sal B＋H₂O₂组和高浓度Sal B＋H₂O₂组。应用MTT、流式细胞仪(FCM)及Hoechst标记的方法检测Sal B对氧化应激介导的细胞活性下降以及凋亡效应的影响;通过DCF荧光染色的方法检测过氧化氢及Sal B对细胞内活性氧生成的影响;用Western blotting的方法检测p-ERK1/2表达情况。结果: MTT结果显示不同浓度的Sal B共处理BMSCs 24 h能够提高氧化应激情况下的细胞活性,其中中浓度组的作用更为明显。Hoechst标记以及FCM检测的结果表明:10 μmol/L Sal B处理能够提高细胞活性,减少凋亡数。正常组细胞的DCF阳性细胞率为28.7％±8.1％,经500 μmol/L H₂O₂刺激24 h后,阳性细胞数急剧上升,高达86.9％±12.4％。而10 μmol/L Sal B处理 组的上升不明显,仅有42.1％±10.8％。由此可见,Sal B处理可以减少细胞内活性氧的生成;细胞在氧化应激的条件下p-ERK1/2在15 min内开始上调,持续120 min。而这种上调经10 μmol/L Sal B处理可以有效降低,同时Sal B可以降低细胞基础的p-ERK1/2表达。结论: Sal B 增强BMSCs抗氧化应激能力从而减少H₂O₂刺激引起的细胞凋亡,其保护机制可能与参与调节凋亡相关信号通路MEK/ERK1/2和抑制细胞内活性氧生成有关。     

STS‐1 promotes IFN‐α induced autophagy by activating the JAK1‐STAT1 signaling pathway in B cells

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the overexpression of IFN‐α. IFN‐α induces autophagy via the JAK1‐STAT1 signaling pathway, contributing to the pathogenesis of SLE. Recent studies reported that B cells from patients with SLE and NZB/W F1 mice had enhanced autophagy activity; however, the mechanism still remains unknown. Here, we show that the protein tyrosine phosphatase STS‐1 (suppressor of T‐cell receptor signaling 1) was significantly overexpressed in B cells from patients with SLE and MRL/lpr mice. Notably, STS‐1 promoted IFN‐α‐induced autophagy in B cells by enhancing the JAK1‐STAT1 signaling activation. STS‐1 inhibited the phosphorylation of the E3 ubiquitin protein ligase c‐cbl, and subsequently promoted IFN‐α‐induced phosphorylation of tyrosine kinase 2, leading to JAK1‐STAT1 signaling activation. Furthermore, STAT1 and JAK1 inhibitors blocked the IFN‐α‐induced autophagy promoted by STS‐1, indicating that STS‐1 promotes IFN‐α‐induced autophagy via the JAK1‐STAT1 signaling. Our results demonstrate the importance of STS‐1 in regulating IFN‐α‐induced autophagy in B cells, and this could be used as a therapeutic approach to treat SLE.     

Topical treatment of all‐trans retinoic acid inhibits murine melanoma partly by promoting CD8+ T‐cell immunity

All‐trans retinoic acid (atRA), the main biologically active metabolite of vitamin A, has been implicated in immunoregulation and anti‐cancer. A recent finding that vitamin A could decrease the risk of melanoma in humans indicates the beneficial role of atRA in melanoma. However, it remains unknown whether topical application of atRA could inhibit melanoma growth by influencing tumour immunity. We demonstrate topical application of tretinoin ointment (atRA as the active ingredient) effectively inhibited B16F10 melanoma growth. This is accompanied by markedly enhanced CD8⁺ T‐cell responses, as evidenced by significantly increased proportions of effector CD8⁺ T cells expressing granzyme B, tumour necrosis factor‐α, or interferon‐γ, and Ki67⁺ proliferating CD8⁺ T cells in atRA‐treated tumours compared with vaseline controls. Furthermore, topical atRA treatment promoted the differentiation of effector CD8⁺ T cells in draining lymph nodes (DLN) of tumour‐bearing mice. Interestingly, atRA did not affect tumoral CD4⁺ T‐cell response, and even inhibited the differentiation of interferon‐γ‐expressing T helper type 1 cells in DLN. Importantly, we demonstrated that the tumour‐inhibitory effect of atRA was partly dependent on CD8⁺ T cells, as CD8⁺ T‐cell depletion restored tumour volumes in atRA‐treated mice, which, however, was still significantly smaller than those in vaseline‐treated mice. Finally, we demonstrated that atRA up‐regulated MHCI expression in B16F10 cells, and DLN cells from tumour‐bearing mice had a significantly higher killing rate when culturing with atRA‐treated B16F10 cells. Hence, our study demonstrates that topical atRA treatment effectively inhibits melanoma growth partly by promoting the differentiation and the cytotoxic function of effector CD8⁺ T cells.     

Expression of CD5 and CD38 by human CD5− B cells: Requirement for special stimuli

In this study the mode of expression of CD5 by human tonsillar CD5^? B cells after stimulation with different agents was investigated. Resting B cells were separated into CD5⁺ and CD5^? cells and the two cell fractions exposed to phorbol 12-myristate 13-acetate (PMA). CD5^? B cells expressed CD5 and maximum CD5 expression was achieved after approximately 60 h of culture. Based upon the proportions of cells that express CD5 as well as those of the cells surviving in culture, it was calculated that 15–25 % of the total CD5^? B cells were induced to express CD5. Unlike CD5^? B cells, CD5⁺ B cells proliferated vigorously in response to PMA as assessed by [³H] thymidine incorporation and cell cycle analysis in vitro. However, the expression of CD5 by CD5^? B cells was not related to the selective expansion of some CD5⁺ B cells left over as contaminant cells since this occurred in the absence of cell proliferation. Upon exposure to PMA, CD5^? B cells remained in the G0-G1 phases of the cell cycle and did not express the Ki67 antigen or incorporate [³H] thymidine. Furthermore, mitomycin C treatment of the CD5^? B cells did not prevent CD5 expression. Phenotypic studies disclosed that CD5⁺ B cells but not CD5^? B cells expressed CD39. This finding offered the opportunity to carry out an additional control experiment. Separation of the two populations according to the expression of CD39 confirmed the finding obtained by fractionating the cells into CD5⁺ and CD5^? B cells. The cells induced to express CD5 also expressed CD38 that was not detected on resting CD5^? B cells. In this respect, the CD5^? B cells that converted into CD5⁺ cells (inducible CD5⁺ B cells) resembled the cells from the CD5⁺ B cell fractions that up-regulated CD5 and also expressed CD38 upon exposure to PMA alone. Another example of coordinate expression of these two antigens was the finding that exposure to PMA in the presence of recombinant interleukin-4 (rIL-4) resulted in inhibition of the expression of CD5 and CD38. Although virtually all of the tonsillar CD5^? B cells expressed the CD69 activation marker, no cells other than those co-expressing CD5 and CD38 were induced to express CD5 by PMA alone. Resting CD5^? B cells failed to express CD5 and/or CD38 when cultured with PMA in the presence of EL4 T cells and IL-4-free T cell supernatants. Although this combination of stimuli induced a vigorous cell proliferation, the failure to express CD5 and CD38 was not related to cell cycling, since mitomicyn C-treated CD5^? B cells also failed to express CD5 or CD38 when exposed to PMA in the presence of EL4 cells with or without T cell supernatants. Thus, exposure to T cells alone was sufficient to down-regulate CD5 and CD38 expression. Collectively, the above findings indicate that mature CD5^? B cells can follow distinct pathways of differentiation depending upon the nature of the stimuli encountered, and that CD5 expression may identify a special B cell subset or a particular stage of B cell differentiation.     

IRF‐5 and NF‐κB p50 co‐regulate IFN‐β and IL‐6 expression in TLR9‐stimulated human plasmacytoid dendritic cells

Synthetic oligonucleotides (ODN) expressing CpG motifs mimic the ability of bacterial DNA to trigger the innate immune system via TLR9. Plasmacytoid dendritic cells (pDCs) make a critical contribution to the ensuing immune response. This work examines the induction of antiviral (IFN‐β) and pro‐inflammatory (IL‐6) cytokines by CpG‐stimulated human pDCs and the human CAL‐1 pDC cell line. Results show that interferon regulatory factor‐5 (IRF‐5) and NF‐κB p50 are key co‐regulators of IFN‐β and IL‐6 expression following TLR9‐mediated activation of human pDCs. The nuclear accumulation of IRF‐1 was also observed, but this was a late event that was dependant on type 1 IFN and unrelated to the initiation of gene expression. IRF‐8 was identified as a novel negative regulator of gene activation in CpG‐stimulated pDCs. As variants of IRF‐5 and IRF‐8 were recently found to correlate with susceptibility to certain autoimmune diseases, these findings are relevant to our understanding of the pharmacologic effects of “K” ODN and the role of TLR9 ligation under physiologic, pathologic, and therapeutic conditions.     

Role of 5‐HT2A, 5‐HT4 and 5‐HT7 receptors in the antigen‐induced airway hyperresponsiveness in guinea‐pigs

Background A possible role of 5‐hydroxytryptamine (5‐HT) in the origin of antigen‐induced airway hyperresponsiveness (AI‐AHR) has been scarcely investigated. Objective To explore the participation of different 5‐HT receptors in the development of AI‐AHR in guinea‐pigs. Methods Lung resistance was measured in anaesthetized guinea‐pigs sensitized to ovalbumin (OVA). Dose–response curves to intravenous (i.v.) acetylcholine (ACh) were performed before and 1 h after antigenic challenge and expressed as the 200% provocative dose (PD₂₀₀). Organ bath experiments, confocal microscopy and RT‐PCR were additionally used. The 5‐HT content in lung homogenates was measured by HPLC. Results Antigenic challenge significantly decreased PD₂₀₀, indicating the development of AI‐AHR. This hyperresponsiveness was abolished by a combination of methiothepin (5‐HT₁/5‐HT₂/5‐HT₅/5‐HT₆/5‐HT₇ receptors antagonist) and tropisetron (5‐HT₃/5‐HT₄ antagonist). Other 5‐HT receptor antagonists showed three different patterns of response. Firstly, WAY100135 (5‐HT_1A antagonist) and ondansetron (5‐HT₃ antagonist) did not modify the AI‐AHR. Secondly, SB269970 (5‐HT₇ antagonist), GR113808 (5‐HT₄ antagonist), tropisetron or methiothepin abolished the AI‐AHR. Thirdly, ketanserin (5‐HT_2A antagonist) produced airway hyporresponsiveness. Animals with bilateral vagotomy did not develop AI‐AHR. Experiments in tracheal rings showed that pre‐incubation with LP44 or cisapride (agonists of 5‐HT₇ and 5‐HT₄ receptors, respectively) induced a significant increase of the cholinergic contractile response to the electrical field stimulation. In sensitized lung parenchyma strips, ketanserin diminished the contractile responses to ACh. Sensitization was associated with a ninefold increase in the 5‐HT content of lung homogenates. Confocal microscopy showed that sensitization enhanced the immunolabelling and co‐localization of nicotinic receptor and 5‐HT in airway epithelium, probably located in pulmonary neuroendocrine cells (PNECs). RT‐PCR demonstrated that neither sensitization nor antigen challenge modified the 5‐HT_2A receptor mRNA levels. Conclusions Our results suggested that 5‐HT was involved in the development of AI‐AHR to ACh in guinea‐pigs. Specifically, 5‐HT_2A, 5‐HT₄ and 5‐HT₇ receptors seem to be particularly involved in this phenomenon. Participation of 5‐HT might probably be favoured by the enhancement of the PNECs 5‐HT content observed after sensitization. Cite this as: P. Segura, M. H. Vargas, G. Córdoba‐Rodríguez, J. Chávez, J. L. Arreola, P. Campos‐Bedolla, V. Ruiz, L. M. García‐Hernández, C. Méndez and L. M. Montaño, Clinical & Experimental Allergy, 2010 (40) 327– 338.     

Detection of ABCB5 tumour antigen‐specific CD8+ T cells in melanoma patients and implications for immunotherapy

ATP binding cassette subfamily B member 5 (ABCB5) has been identified as a tumour‐initiating cell marker and is expressed in various malignancies, including melanoma. Moreover, treatment with anti‐ABCB5 monoclonal antibodies has been shown to inhibit tumour growth in xenotransplantation models. Therefore, ABCB5 represents a potential target for cancer immunotherapy. However, cellular immune responses against ABCB5 in humans have not been described so far. Here, we investigated whether ABCB5‐reactive T cells are present in human melanoma patients and tested the applicability of ABCB5‐derived peptides for experimental induction of human T cell responses. Peripheral blood mononuclear cells (PBMNC) isolated from blood samples of melanoma patients (n = 40) were stimulated with ABCB5 peptides, followed by intracellular cytokine staining (ICS) for interferon (IFN)‐γ and tumour necrosis factor (TNF)‐α. To evaluate immunogenicity of ABCB5 peptides in naive healthy donors, CD8 T cells were co‐cultured with ABCB5 antigen‐loaded autologous dendritic cells (DC). ABCB5 reactivity in expanded T cells was assessed similarly by ICS. ABCB5‐reactive CD8⁺ T cells were detected ex vivo in 19 of 29 patients, melanoma antigen recognised by T cells (MART‐1)‐reactive CD8⁺ T cells in six of 21 patients. In this small, heterogeneous cohort, reactivity against ABCB5 was significantly higher than against MART‐1. It occurred significantly more often and independently of clinical characteristics. Reactivity against ABCB5 could be induced in 14 of 16 healthy donors in vitro by repeated stimulation with peptide‐loaded autologous DC. As ABCB5‐reactive CD8 T cells can be found in the peripheral blood of melanoma patients and an ABCB5‐specific response can be induced in vitro in naive donors, ABCB5 could be a new target for immunotherapies in melanoma.     

Gx‐50 reduces β‐amyloid‐induced TNF‐α, IL‐1β, NO,and PGE2 expression and inhibits NF‐κB signaling in a mouse model of Alzheimer's disease

Chronic inflammation, which is regulated by overactivated microglia in the brain, accelerates the occurrence and development of Alzheimer's disease (AD). Gx‐50 has been investigated as a novel drug for the treatment of AD in our previous studies. Here, we investigated whether gx‐50 possesses anti‐inflammatory effects in primary rat microglia and a mouse model of AD, amyloid precursor protein (APP) Tg mice. The expression of TNF‐α, IL‐1β, NO, prostaglandin E2, and the expression of iNOS and COX2 were inhibited by gx‐50 in amyloid β (Aβ) treated rat microglia; additionally, microglial activation and the expression of IL‐1β, iNOS, and COX2 were also significantly suppressed by gx‐50 in APP⁺ transgenic mice. Furthermore, gx‐50 inhibited the activation of NF‐κB and MAPK cascades in vitro and in vivo in APP‐Tg mice. Moreover, the expression of TLR4 and its downstream signaling proteins MyD88 and tumor necrosis factor receptor associated factor 6 (TRAF6) was reduced by gx‐50 in vitro and in vivo. Interestingly, silencing of TLR4 reduced Aβ‐induced upregulation of IL‐1β and TRAF6 to levels similar to gx‐50 inhibition; moreover, overexpression of TLR4 increased the expression of MyD88 and TRAF6, which was significantly reduced by gx‐50. These findings provide strong evidence that gx‐50 has anti‐inflammatory effects against Aβ‐triggered microglial overactivation via a mechanism that involves the TLR4‐mediated NF‐κBB/MAPK signaling cascade.     

31P and 1H MRS of DB‐1 melanoma xenografts: lonidamine selectively decreases tumor intracellular pH and energy status and sensitizes tumors to melphalan

In vivo ³¹P MRS demonstrates that human melanoma xenografts in immunosuppressed mice treated with lonidamine (LND, 100 mg/kg intraperitoneally) exhibit a decrease in intracellular pH (pH_i) from 6.90 ± 0.05 to 6.33 ± 0.10 (p < 0.001), a slight decrease in extracellular pH (pH_e) from 7.00 ± 0.04 to 6.80 ± 0.07 (p > 0.05) and a monotonic decline in bioenergetics (nucleoside triphosphate/inorganic phosphate) of 66.8 ± 5.7% (p < 0.001) relative to the baseline level. Both bioenergetics and pH_i decreases were sustained for at least 3 h following LND treatment. Liver exhibited a transient intracellular acidification by 0.2 ± 0.1 pH units (p > 0.05) at 20 min post‐LND, with no significant change in pH_e and a small transient decrease in bioenergetics (32.9 ± 10.6%, p > 0.05) at 40 min post‐LND. No changes in pH_i or adenosine triphosphate/inorganic phosphate were detected in the brain (pH_i, bioenergetics; p > 0.1) or skeletal muscle (pH_i, pH_e, bioenergetics; p > 0.1) for at least 120 min post‐LND. Steady‐state tumor lactate monitored by ¹H MRS with a selective multiquantum pulse sequence with Hadamard localization increased approximately three‐fold (p = 0.009). Treatment with LND increased the systemic melanoma response to melphalan (LPAM; 7.5 mg/kg intravenously), producing a growth delay of 19.9 ± 2.0 days (tumor doubling time, 6.15 ± 0.31 days; log₁₀ cell kill, 0.975 ± 0.110; cell kill, 89.4 ± 2.2%) compared with LND alone of 1.1 ± 0.1 days and LPAM alone of 4.0 ± 0.0 days. The study demonstrates that the effects of LND on tumor pH_i and bioenergetics may sensitize melanoma to pH‐dependent therapeutics, such as chemotherapy with alkylating agents or hyperthermia. Copyright © 2012 John Wiley & Sons, Ltd.     

Up‐regulation of miR‐455‐5p by the TGF‐β–SMAD signalling axis promotes the proliferation of oral squamous cancer cells by targeting UBE2B

MicroRNAs (miRNAs) are involved in the tumourigenesis of various cancers by regulating their downstream targets. To identify the changes of miRNAs in oral squamous cell carcinoma (OSCC), we investigated the expression profiles of miRNAs in 40 pairs of OSCC specimens and their matched non‐tumour epithelial tissues. Our data revealed higher miR‐455‐5p expression in the tumour tissues than in the normal tissues; the expression was also higher in oral cancer cell lines than in normal keratinocyte cell lines. MiR‐455‐5p knockdown reduced both the anchorage‐independent growth and the proliferative ability of oral cancer cells, and these factors increased in miR‐455‐5p‐overexpressing cells. Furthermore, by analysing the array data of patients with cancer and cell lines, we identified ubiquitin‐conjugating enzyme E2B (UBE2B) as a target of miR‐455‐5p, and further validated this using 3′‐untranslated region luciferase reporter assays and western blot analysis. We also demonstrated that UBE2B suppression rescued the impaired growth ability of miR‐455‐5p‐knockdown cells. Furthermore, we observed that miR‐455‐5p expression was regulated, at least in part, by the transforming growth factor‐β (TGF‐β) pathway through the binding of SMAD3 to specific promoter regions. Notably, miR‐455‐5p expression was associated with the nodal status, stage, and overall survival in our patients, suggesting that miR‐455‐5p is a potential marker for predicting the prognosis of patients with oral cancer. In conclusion, we reveal that miR‐455‐5p expression is regulated by the TGF‐β‐dependent pathway, which subsequently leads to UBE2B down‐regulation and contributes to oral cancer tumourigenesis. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Antibacterial and Anticancer activity of ε ‐poly‐L‐lysine (ε ‐PL) produced by a marine Bacillus subtilis sp.

A marine Bacillus subtilis SDNS was isolated from sea water in Alexandria and identified using 16S rDNA sequence analysis. The bacterium produced a compound active against a number of gram negativeve bacteria. Moreover, the anticancer activity of this bacterium was tested against three different human cell lines (Hela S3, HepG2 and CaCo). The highest inhibition activity was recorded against Hela S3 cell line (77.2%), while almost no activity was recorded towards CaCo cell line. HPLC and TLC analyses supported evidence that Bacillus subtilis SDNS product is ?;‐poly‐L‐lysine. To achieve maximum production, Plackett‐Burman experimental design was applied. A 1.5 fold increase was observed when Bacillus subtilis SDNS was grown in optimized medium composed of g/l: (NH₄)₂SO₄, 15; K₂HPO₄, 0.3; KH₂PO₄, 2; MgSO₄ · 7 H₂O, 1; ZnSO₄ · 7 H₂O, 0; FeSO₄ · 7 H₂O, 0.03; glucose, 25; yeast extract, 1, pH 6.8. Under optimized culture condition, a product value of 76.3 mg/l could be obtained. According to available literature, this is the first announcement for the production of ?;‐poly‐L‐lysine (?;‐PL) by a member of genus Bacillus. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)