Induction Of Interleukin Research Articles

Signals that induce IL-10 production by peripheral regulatory T cells

Abstract Inflammatory bowel disease (IBD) is an immune-mediated disease of the intestinal tract caused by chronic inflammation that can be relapsing and remitting. This inflammation leads to flares that often require patients to be treated with life-long biologic therapy. Interleukin 10 (IL-10) is an immunosuppressive cytokine produced by effector T cells, especially regulatory T cells (Tregs), to limit inflammatory responses to both foreign and self-antigens. Although IL-10-producing peripheral Tregs (IL-10+ pTregs) are thought to play a mitigating role in murine models of colitis, signals that control transcriptional regulation of the Il10 locus are not well understood. Here, we have examined cytokine and non-cytokine signals that enhance the induction of IL-10+ pTregs in vitro and in vivo. We find that in vitro a mix of inflammatory cytokines acting in concert with IL-2 and on-going TGFβ signaling induce the production of Foxp3+IL-10+ pTregs from Foxp3+IL-10- precursors. Ongoing studies are directed at extending these findings to the in vivo induction of IL-10-producing pTreg cells, and examining the ability of these cells to curb intestinal inflammation driven by aberrant effector T cell responses against the intestinal microbiota. Ultimately, we hope that by identifying signals to amplify our target population, we can perform genomic analyses to better decipher what modulates the transcriptional landscape of the Il10 locus, and identify novel immune therapies for patients with IBD.

Ambient particulate matter activates the aryl hydrocarbon receptor in dendritic cells and enhances Th17 polarization

The objective of this study was to explore the role of the aryl hydrocarbon receptor (AhR) in ambient particulate matter (PM)-mediated activation of dendritic cells (DCs) and Th17-immune responses in vitro. To assess the potential role of the AhR in PM-mediated activation of DCs, co-stimulation, and cytokine expression, bone marrow (BM)-derived macrophages and DCs from C57BL/6 wildtype or AhR knockout (AhR−/−) mice were treated with PM. Th17 differentiation was assessed via co-cultures of wildtype or AhR−/− BMDCs with autologous naive T cells. PM2.5 significantly induced AhR DNA binding activity to dioxin responsive elements (DRE) and expression of the AhR repressor (AhRR), cytochrome P450 (CYP) 1A1, and CYP1B1, indicating activation of the AhR. In activated (OVA sensitized) BMDCs, PM2.5 induced interleukin (IL)-1β, CD80, CD86, and MHC class II, suggesting enhanced DC activation, co-stimulation, and antigen presentation; responses that were abolished in AhR deficient DCs. DC-T cell co-cultures treated with PM and lipopolysaccharide (LPS) led to elevated IL-17A and IL-22 expression at the mRNA level, which is mediated by the AhR. PM-treated DCs were essential in endowing T cells with a Th17-phenotype, which was associated with enhanced expression of MHC class II and cyclooxygenase (COX)-2. In conclusion, PM enhances DC activation that primes naive T cell differentiation towards a Th17-like phenotype in an AhR-dependent manner.

Modulation of human dendritic cell activity by Giardia and helminth antigens.

Giardia duodenalis is a common intestinal protozoan parasite known to modulate host immune responses, including dendritic cell (DC) function. Coinfections of intestinal pathogens are common, and thus, DCs may be concurrently exposed to antigens from multiple parasites. Here, we investigated the effects of G.duodenalis products on human monocyte-derived DC function independently and in combination with helminth antigens (Ascaris suum and Trichuris suis). All antigens individually induced an anti-inflammatory phenotype in DCs, reducing lipopolysaccharide (LPS)-induced interleukin (IL)-6, IL-12p70 and tumour necrosis factor (TNF)-α secretion. G.duodenalis and T.suis products also consistently upregulated IL-10 production. Despite a similar modulation of cytokine secretion, additive effects between Giardia and helminth products were not observed, indicating a dominant effect of a single parasite stimulus and limited interactive effects on DC function. G.duodenalis trophozoites induced rapid apoptosis in DCs, which was not observed with the helminth antigens suggesting that the modulatory effects of G.duodenalis may override that of A.suum and T.suis. Thus, G.duodenalis modulates DC activity by modulating cytokine secretion and/or inducing apoptosis, which may be a parasite-driven mechanism to dampen host immunity and establish chronic infections. The differential mechanisms of DC modulation by intestinal parasites warrant further attention.

Anti-inflammatory effects of α-linolenic acid in M1-like macrophages are associated with enhanced production of oxylipins from α-linolenic and linoleic acid

Chronic inflammation, mediated in large part by proinflammatory macrophage populations, contributes directly to the induction and perpetuation of metabolic diseases, including obesity, insulin resistance and type 2 diabetes. Polyunsaturated fatty acids (PUFAs) can have profound effects on inflammation through the formation of bioactive oxygenated metabolites called oxylipins. The objective of this study was to determine if exposure to the dietary omega-3 PUFA α-linolenic acid (ALA) can dampen the inflammatory properties of classically activated (M1-like) macrophages derived from the human THP-1 cell line and to examine the accompanying alterations in oxylipin secretion. We find that ALA treatment leads to a reduction in lipopolysaccharide (LPS)-induced interleukin (IL)-1β, IL-6 and tumor necrosis factor-α production. Although ALA is known to be converted to longer-chain PUFAs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), DHA oxylipins were reduced overall by ALA treatment, as was LPS-induced secretion of EPA oxylipins. In contrast, we observed profound increases in oxylipins directly derived from ALA. Lipoxygenase products of linoleic acid were also dramatically increased, and LPS-induced production of AA oxylipins, particularly prostaglandin D2, was reduced. These results suggest that ALA may act to dampen the inflammatory phenotype of M1-like macrophages by a unique set of mechanisms distinct from those used by the long-chain omega-3 fatty acids EPA and DHA. Thus, there is strong rationale for investigating the functions of ALA oxylipins and lesser-known LA oxylipins since they hold promise as anti-inflammatory agents.

Induction of Interleukin-10 Producing Dendritic Cells As a Tool to Suppress Allergen-Specific T Helper 2 Responses.

Dendritic cells (DCs) are gatekeepers of the immune system that control induction and polarization of primary, antigen-specific immune responses. Depending on their maturation/activation status, the molecules expressed on their surface, and the cytokines produced DCs have been shown to either elicit immune responses through activation of effector T cells or induce tolerance through induction of either T cell anergy, regulatory T cells, or production of regulatory cytokines. Among the cytokines produced by tolerogenic DCs, interleukin 10 (IL-10) is a key regulatory cytokine limiting und ultimately terminating excessive T-cell responses to microbial pathogens to prevent chronic inflammation and tissue damage. Because of their important role in preventing autoimmune diseases, transplant rejection, allergic reactions, or in controlling chronic inflammation DCs have become an interesting tool to modulate antigen-specific immune responses. For the treatment of allergic inflammation, the aim is to downregulate allergen-specific T helper 2 (Th2) responses and the associated clinical symptoms [allergen-driven Th2 activation, Th2-driven immunoglobulin E (IgE) production, IgE-mediated mast cell and basophil activation, allergic inflammation]. Here, combining the presentation of allergens by DCs with a pro-tolerogenic, IL-10-producing phenotype is of special interest to modulate allergen-specific immune responses in the treatment of allergic diseases. This review discusses the reported strategies to induce DC-derived IL-10 secretion for the suppression of allergen-specific Th2-responses with a focus on IL-10 treatment, IL-10 transduction, and the usage of both whole bacteria and bacteria-derived components. Interestingly, while IL-10-producing DCs induced either by IL-10 treatment or IL-10 transduction are arrested in an immature/semi-mature state, treatment of DCs with live or killed bacteria as well as isolated bacterial components results in the induction of both anti-inflammatory IL-10 and pro-inflammatory, Th1-promoting IL-12 secretion often paralleled by an enhanced expression of co-stimulatory molecules on the stimulated DCs. By the secretion of DC-derived exosomes or CC-chemokine ligand 18, as well as the expression of inhibitory molecules like cytotoxic T lymphocyte-associated antigen 4, TNF receptor superfamily member 4, Ig-like transcript-22/cluster of differentiation 85, or programmed death-1, IL-10-producing DCs have been repeatedly shown to suppress antigen-specific Th2-responses. Therefore, DC-based vaccination approaches hold great potential to improve the treatment of allergic diseases.

Interleukin 6 Plays a Role in the Migration of Magnetically Levitated Mesenchymal Stem Cells Spheroids

Mesenchymal stem cells (MSCs) reside quiescently within a specialised ‘niche’ environment in the bone marrow. However, following appropriate signalling cues, MSCs mobilise and migrate out from the niche, typically toward either sites of injury (a regenerative response) or toward primary tumours (an intrinsic homing response, which promotes MSCs as cellular vectors for therapeutic delivery). To date, very little is known about MSC mobilisation. By adopting a 3D MSC niche model, whereby MSC spheroids are cultured within a type I collagen gel, recent studies have highlighted interleukin-6 (IL-6) as a key cytokine involved in MSC migration. Herein, the ability of IL-6 to induce MSC migration was further investigated, and the key matrix metalloproteinases used to effect cell mobilisation were identified. Briefly, the impact of IL-6 on the MSC migration in a two-dimensional model systems was characterised—both visually using an Ibidi chemotaxis plate array (assessing for directional migration) and then via a standard 2D monolayer experiment, where cultured cells were challenged with IL-6 and extracted media tested using an Abcam Human MMP membrane antibody array. The 2D assay displayed a strong migratory response toward IL-6 and analysis of the membrane arrays data showed significant increases of several key MMPs. Both data sets indicated that IL-6 is important in MSC mobilisation and migration. We also investigated the impact of IL-6 induction on MSCs in 3D spheroid culture, serving as a simplistic model of the bone marrow niche, characterised by fluorescently tagged magnetic nanoparticles and identical membrane antibody arrays. An increase in MMP levels secreted by cells treated with 1 ng/mL IL-6 versus control conditions was noted in addition to migration of cells away from the central spheroid mass.

Induction of interleukin-6 trigger an apoptosis through IL-17 and stat3 pathway that alleviated by phycocyanin treatment

This study was to analyze the optimum dose of IL-6 induction in pregnant rats that could trigger an increase in mean arterial pressure and protein as two symptoms of preeclampsia. A total of 25 pregnant rats was divided into 5 groups, including pregnant rats the control group (without induction of IL-6), a group of pregnant rats were given an induction in IL-6 doses of 1.25 ng/day, a group of pregnant rats given doses of IL-6 induction 2.5 ng/day, a group of pregnant rats were given an induction of IL-6 doses of 5 ng/day, and groups of pregnant rats were given an induction in IL-6 doses of 10 ng/day. Induction of IL-6 was performed on the tenth day of gestation for 5 days. The expression of caspase-3, IL-17, and STAT3 were analyzed by confocal laser scanning microscopy. The expression of caspase-3, IL-17 and STAT3 was significantly higher in preeclampsia group than the control group (p<0.05). The expression of caspase-3 decreased significantly in all groups were treated by phycocyanin compared to the preeclamptic group (p<0.05), but has not been able to reach expression comparable to the control group (p<0.05). Expression of IL-17 decreased significantly in the group given the two highest doses of phycocyanin compared to the preeclampsia group (p<0.05). STAT3 expression decreased significantly in all groups were treatedby phycocyanin compared to the preeclamptic group (p<0.05), reached expression comparable to the control group in the group received phycocyanin at doses of 10 and 20 ng (p> 0.05). In conclusion, IL-6 on pregnant rats were able to increase apoptosis through IL-17 and STAT pathway. Inhibition of apoptosis due to phycoyanin treatment not only involve the formation of IL-17, this data is found in phycocyanin doses of 10 and 20 ng.

Cucumis sativus Aqueous Fraction Inhibits Angiotensin II-Induced Inflammation and Oxidative Stress In Vitro.

Inflammation and oxidative stress play major roles in endothelial dysfunction, and are key factors in the progression of cardiovascular diseases. The aim of this study was to evaluate in vitro the effect of three subfractions (SFs) from the Cucumis sativus aqueous fraction to reduce inflammatory factors and oxidative stress induced by angiotensin II (Ang II) in human microvascular endothelial cells-1 (HMEC-1) cells. The cells were cultured with different concentrations of Ang II and 0.08 or 10 μg/mL of SF1, SF2, or SF3, or 10 μmol of losartan as a control. IL-6 (Interleukin 6) concentration was quantified. To identify the most effective SF combinations, HMEC-1 cells were cultured as described above in the presence of four combinations of SF1 and SF3. Then, the effects of the most effective combination on the expression of adhesion molecules, the production of reactive oxygen species (ROS), and the bioavailability of nitric oxide (NO) were evaluated. Finally, a mass spectrometry analysis was performed. Both SF1 and SF3 subfractions decreased the induction of IL-6 by Ang II, and C4 (SF1 and SF3, 10 μg/mL each) was the most effective combination to inhibit the production of IL-6. Additionally, C4 prevented the expression of adhesion molecules, reduced the production of ROS, and increased the bioavailability of NO. Glycine, arginine, asparagine, lysine, and aspartic acid were the main components of both subfractions. These results demonstrate that C4 has anti-inflammatory and antioxidant effects.

Effects of Graphene Oxide Nanoparticles on the Immune System Biomarkers Produced by RAW 264.7 and Human Whole Blood Cell Cultures.

Graphene oxide nanoparticles (GONPs) have attracted a lot of attention due to their many applications. These applications include batteries, super capacitors, drug delivery and biosensing. However, few studies have investigated the effects of these nanoparticles on the immune system. In this study, the in vitro effects of GONPs on the immune system was evaluated by exposing murine macrophages, RAW 264.7 cells and human whole blood cell cultures (to GONPs. The effects of GONPs on RAW cells were monitored under basal conditions. The whole blood cell cultures were exposed to GONPs in the presence or absence of the mitogens lipopolysaccharide (LPS) and phytohaemmagglutinin (PHA). A number of parameters were monitored for both RAW and whole blood cell cultures, these included cytotoxicity, inflammatory biomarkers, cytokines of the acquired immune system and a proteome profile analysis. The GONPs were cytotoxic to both RAW and whole blood cell cultures at 500 μg/mL. In the absence of LPS, GONPs elicited an inflammatory response from the murine macrophage, RAW and whole blood cell cultures at 15.6 and 5 μg/mL respectively. This activation was further corroborated by proteome profile analysis of both experimental cultures. GONPs inhibited LPS induced interleukin 6 (IL-6) synthesis and PHA induced interferon gamma (IFNγ) synthesis by whole blood cell cultures in a dose dependent manner. In the absence of mitogens, GONPs stimulated IL-10 synthesis by whole blood cell cultures. The current study shows that GONPs modulate immune system biomarkers and that these may pose a health risk to individuals exposed to this type of nanoparticle.

Polyethylenimine-Mediated CpG Oligodeoxynucleotide Delivery Stimulates Bifurcated Cytokine Induction.

CpG oligodeoxynucleotides (CpG ODNs) bind to toll-like receptor 9 (TLR9) and activate the immune system. Thus, CpG ODNs have attracted considerable interest as immunotherapeutic agents or adjuvants for many diseases. Herein we report that polyethylenimine (PEI) functions as a multifunctional vector for both enhancing and regulating the immunostimulatory activity of CpG ODNs. PEI and CpG ODNs formed nanopolyplexes (NPs), which possessed good biocompatibility. PEI-CpG ODN NPs facilitated the internalization of CpG ODNs and induced increasing amounts of cytokines. Most importantly, PEI-CpG ODN NPs induced interleukin-6 (IL-6) and interferon-α (IFN-α) simultaneously, while class B CpG ODNs induced only IL-6. In contrast to class C CpG ODNs, which also simultaneously induce IFN-α and IL-6, the ratio of IFN-α and IL-6 induced by PEI-CpG ODN NPs could be regulated by changing the N/P ratio. This flexible bifurcated cytokine is promising for treating diseases such as cancer that require IL-6 and IFN-α simultaneously. Our findings propose a regulatory effect of PEI on the immunostimulatory activity of CpG ODNs, which will shed light on the development of highly efficient nonviral vectors for CpG ODN-based immunotherapy.

The Superantigen Toxic Shock Syndrome Toxin 1 Alters Human Aortic Endothelial Cell Function.

ABSTRACTStaphylococcus aureus infective endocarditis (IE) is a fast-progressing and tissue-destructive infection of the cardiac endothelium. The superantigens (SAgs) toxic shock syndrome toxin 1 (TSST-1), staphylococcal enterotoxin C (SEC), and the toxins encoded by the enterotoxin gene cluster (egc) play a novel and essential role in the etiology of S. aureus IE. Recent studies indicate that SAgs act at the infection site to cause tissue pathology and promote vegetation growth. The underlying mechanism of SAg involvement has not been clearly defined. In SAg-mediated responses, immune cell priming is considered a primary triggering event leading to endothelial cell activation and altered function. Utilizing immortalized human aortic endothelial cells (iHAECs), we demonstrated that TSST-1 directly activates iHAECs, as documented by upregulation of vascular and intercellular adhesion molecules (VCAM-1 and ICAM-1). TSST-1-mediated activation results in increased monolayer permeability and defects in vascular reendothelialization. Yet stimulation of iHAECs with TSST-1 fails to induce interleukin-8 (IL-8) and IL-6 production. Furthermore, simultaneous stimulation of iHAECs with TSST-1 and lipopolysaccharide (LPS) inhibits LPS-mediated IL-8 and IL-6 secretion, even after pretreatment with either of the proinflammatory cytokines tumor necrosis factor alpha (TNF-α) and IL-1β. IL-8 suppression is not mediated by TSST-1 binding to its canonical receptor major histocompatibility complex class II (MHC-II), supporting current evidence for a nonhematopoietic interacting site on SAgs. Together, the data suggest that TSST-1 differentially regulates cell-bound and secreted markers of endothelial cell activation that may result in dysregulated innate immune responses during S. aureus IE. Endothelial changes resulting from the action of SAgs can therefore directly contribute to the aggressive nature of S. aureus IE and development of life-threatening complications.

Zinc ions have a potential to attenuate both Ni ion uptake and Ni ion-induced inflammation

Nickel ions (Ni2+) are eluted from various metallic materials, such as medical devices implanted in human tissues. Previous studies have shown that Ni2+ enters inflammatory cells inducing inflammation. However, the regulation of Ni2+ uptake in cells has not yet been reported in detail. In the present study, we investigated the effects of various divalent cations on Ni2+ uptake and Ni2+-induced interleukin (IL)-8 production in the human monocytic cell line, THP-1. We demonstrated that ZnCl2, MnCl2, and CoCl2 inhibited the Ni2+ uptake, while CuCl2, FeCl2, MgCl2, and divalent metal transporter (DMT)-1 inhibitor, Chlorazol Black, did not. Furthermore, ZnCl2 inhibited Ni2+-induced IL-8 production, correlating with the inhibition of Ni2+ uptake. These results suggested that Ni2+ uptake occurred through Zn2+, Mn2+, and Co2+-sensitive transporters and that the inhibition of Ni2+ uptake resulted in the inhibition of IL-8 production. Furthermore, using an Ni wire-implanted mouse model, we found that Ni wire-induced expression of mouse macrophage inflammatory protein-2 (MIP-2) and cyclooxygenase-2 (COX-2) mRNA in the skin tissue surrounding the wire were enhanced by low Zn conditions. These results suggested that the physiological concentration of Zn2+ modulates Ni2+ uptake by inflammatory cells, and a Zn deficient state might increase sensitivity to Ni.

Helicobacter pylori Type IV Secretion System and Its Adhesin Subunit, CagL, Mediate Potent Inflammatory Responses in Primary Human Endothelial Cells.

The Gram-negative bacterium, Helicobacter pylori, causes chronic gastritis, peptic ulcers, and gastric cancer in humans. Although the gastric epithelium is the primary site of H. pylori colonization, H. pylori can gain access to deeper tissues. Concurring with this notion, H. pylori has been found in the vicinity of endothelial cells in gastric submucosa. Endothelial cells play crucial roles in innate immune response, wound healing and tumorigenesis. This study examines the molecular mechanisms by which H. pylori interacts with and triggers inflammatory responses in endothelial cells. We observed that H. pylori infection of primary human endothelial cells stimulated secretion of the key inflammatory cytokines, interleukin-6 (IL-6) and interleukin-8 (IL-8). In particular, IL-8, a potent chemokine and angiogenic factor, was secreted by H. pylori-infected endothelial cells to levels ~10- to 20-fold higher than that typically observed in H. pylori-infected gastric epithelial cells. These inflammatory responses were triggered by the H. pylori type IV secretion system (T4SS) and the T4SS-associated adhesin CagL, but not the translocation substrate CagA. Moreover, in contrast to integrin α5β1 playing an essential role in IL-8 induction by H. pylori upon infection of gastric epithelial cells, both integrin α5β1 and integrin αvβ3 were dispensable for IL-8 induction in H. pylori-infected endothelial cells. However, epidermal growth factor receptor (EGFR) is crucial for mediating the potent H. pylori-induced IL-8 response in endothelial cells. This study reveals a novel mechanism by which the H. pylori T4SS and its adhesin subunit, CagL, may contribute to H. pylori pathogenesis by stimulating the endothelial innate immune responses, while highlighting EGFR as a potential therapeutic target for controlling H. pylori-induced inflammation.

Short communication: Probiotic induction of interleukin-10 and interleukin-12 production by macrophages is modulated by co-stimulation with microbial components

Probiotic lactobacilli stimulate macrophages and dendritic cells to secrete cytokines and thereby regulate the immune responses of the host. The balance of the IL-10 and IL-12 production induced by a probiotic is crucial for determining the direction of the immune response. In the present study, we examined the ability of microbial components to modify IL-10 and IL-12 production induced by a popular probiotic strain, Lactobacillus casei strain Shirota (LcS), which itself predominantly induces IL-12 production. Microbial ligands for toll-like receptor (TLR)3 and TLR5 further enhanced the IL-12 induction by LcS, whereas ligands for TLR2, TLR4, TLR7, and TLR9 converted the cytokine production pattern from IL-12 predominant to IL-10 predominant. These results indicate that the probiotic induction of IL-10 and IL-12 production can be flexibly modified by co-stimulation with microbial components. This could explain the variety of immunomodulatory functions (immunoactivation or anti-inflammation) exerted by this probiotic strain.

Methamphetamine modulates the production of interleukin-6 and tumor necrosis factor-alpha via the cAMP/PKA/CREB signaling pathway in lipopolysaccharide-activated microglia

Methamphetamine (METH) elicits neuroinflammatory effects that may implicate its regulatory role on the microglial immune response. However, the mechanism underlying this remains unclear. In the present study, the effects of METH on lipopolysaccharide (LPS)-induced interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) productions were tested in BV-2 cells and primary microglial cells. Additionally, western blot analysis was used to examine the phosphorylation of mitogenactivated protein kinases (MAPKs). Next, we detected the alterations in cAMP content and the phosphorylation levels of CREB in microglial cells to determine the involvement of the cAMP/CREB signaling pathway. We also used an adenylyl cyclase (AC) agonist (forskolin) and antagonist (MDL-12330A) and a PKA antagonist (H89) to confirm their participation. We observed that METH alone did not affect the production of IL-6 or TNF-α. In contrast, METH augmented the IL-6 production and inhibited the TNF-α production induced by LPS. A similar effect of forskolin was also observed in BV-2 cells. While MAPK activation was not influenced by METH alone, the LPS-induced phosphorylation of p38, JNK and ERK1/2 were all reduced by METH. Both the concentration of cAMP and the phosphorylation of CREB were increased by METH in LPS-activated microglial cells. The effects of METH were altered by MDL-12330A and H89. Moreover, the inhibition of the phosphorylation of ERK1/2 by METH was also reversed. These results suggest that the differential regulation of IL-6 and TNF-α by METH in LPS-activated microglial cells may be attributable to the cAMP/PKA/CREB signaling pathway.

Toxicity of Urban PM10 and Relation with Tracers of Biomass Burning.

The chemical composition of particles varies with space and time and depends on emission sources, atmospheric chemistry and weather conditions. Evidence suggesting that particles differ in toxicity depending on their chemical composition is growing. This in vitro study investigated the biological effects of PM10 in relation to PM-associated chemicals. PM10 was sampled in ambient air at an urban traffic site (Borgerhout) and a rural background location (Houtem) in Flanders (Belgium). To characterize the toxic potential of PM10, airway epithelial cells (Beas-2B cells) were exposed to particles in vitro. Different endpoints were studied including cell damage and death (cell viability) and the induction of interleukin-8 (IL-8). The mutagenic capacity was assessed using the Ames II Mutagenicity Test. The endotoxin levels in the collected samples were analyzed and the oxidative potential (OP) of PM10 particles was evaluated by electron paramagnetic resonance (EPR) spectroscopy. Chemical characteristics of PM10 included tracers for biomass burning (levoglucosan, mannosan and galactosan), elemental and organic carbon (EC/OC) and polycyclic aromatic hydrocarbons (PAHs). Most samples displayed dose-dependent cytotoxicity and IL-8 induction. Spatial and temporal differences in PM10 toxicity were seen. PM10 collected at the urban site was characterized by increased pro-inflammatory and mutagenic activity as well as higher OP and elevated endotoxin levels compared to the background area. Reduced cell viability (−0.46 < rs < −0.35, p < 0.01) and IL-8 induction (−0.62 < rs < −0.67, p < 0.01) were associated with all markers for biomass burning, levoglucosan, mannosan and galactosan. Furthermore, direct and indirect mutagenicity were associated with tracers for biomass burning, OC, EC and PAHs. Multiple regression analyses showed levoglucosan to explain 16% and 28% of the variance in direct and indirect mutagenicity, respectively. Markers for biomass burning were associated with altered cellular responses and increased mutagenic activity. These findings may indicate a role of biomass burning in the observed adverse health effect of particulate matter.

Fisetin inhibits TNF-α/NF-κB-induced IL-8 expression by targeting PKCδ in human airway epithelial cells

Fisetin (3,7,3′,4′-tetrahydroxyflavone), a natural flavonoid, is a therapeutic agent for respiratory inflammatory diseases such as chronic obstructive pulmonary disease (COPD). However, detailed molecular mechanisms regarding the target protein of fisetin remain unknown.Fisetin significantly reduces tumour necrosis factor alpha (TNF-α)-induced interleukin (IL)-8 levels by inhibiting both nuclear factor kappa B (NF-κB) transcriptional activity and the phosphorylation of its upstream effectors. We show that fisetin prevents interactions between protein kinase C (PKC)δ and TNF receptor-associated factor 2 (TRAF2), thereby inhibiting the inhibitor of kappa B kinase (IKK)/NF-κB downstream signalling cascade. Furthermore, we found that fisetin directly binds to PKCδ in vitro. Our findings provide evidence that fisetin inhibits the TNF-α-activated IKK/NF-κB cascade by targeting PKCδ, thereby mediating inflammatory diseases such as COPD.These data suggest that fisetin is a good therapeutic drug for the treatment of inflammatory lung diseases, such as COPD, by inhibiting the TNF-α/NF-κB signalling pathway.

Differential control of Toll-like receptor 4–induced interleukin-10 induction in macrophages and B cells reveals a role for p90 ribosomal S6 kinases

Increasing evidence has linked dysregulated interleukin (IL)-10 production by IL-10+ve B cells to autoimmunity, highlighting the importance of improving the understanding of the regulation of IL-10 production in these cells. In both B cells and myeloid cells, IL-10 can be produced in response to Toll-like receptor (TLR) agonists. In macrophages, previous studies have established that mitogen- and stress-activated protein kinases (MSKs) regulate IL-10 production via the phosphorylation of cAMP response element–binding (CREB) protein on the IL-10 promoter. We found here that although MSKs are activated in peritoneal B cells in response to TLR4 agonists, neither MSKs nor CREB are required for IL-10 production in these cells. Using a combination of chemical inhibitors and knockout mice, we found that IL-10 induction in B cells was regulated by an ERK1/2- and p90 ribosomal S6 kinase-dependent mechanism, unlike in macrophages in which p90 ribosomal S6 kinase was not required. This observation highlights fundamental differences in the signaling controlling IL-10 production in B cells and macrophages, even though these two cell types respond to a common TLR stimulus.

MiR-451a induced apoptosis of Philadelphia chromosome-positive acute lymphoblastic leukemia cells by targeting IL-6R.

Philadelphia chromosome positive (Ph+) acute lymphoblastic leukemia (ALL) is the most fatal leukemia due to the BCR/ABL fusion protein. This fusion protein can induce interleukin 6 (IL-6) expression in leukemia stem cells (LSCs) which sustain stemness by binding IL-6R and activating the Janus kinase (JAK)/signal transducer and activator of the transcription (STAT) pathway. IL-6R was one of the targets of miR-451a down-regulated in LSCs by BCR/ABL. We investigated the relationship between miR-451a, IL-6R, and BCR/ABL in Ph+ ALL and created a strategy to treat this disease. The expression levels of miR-451a and BCR/ABL of Ph+ ALL patients were examined by real-time quantitative polymerase chain reaction (RT-qPCR) and serum IL-6 was tested by enzyme-linked immunosorbent assay. Ph+ ALL cell line SUP-B15 and Ph- ALL cell line Nalm-6 were treated with miR-451a mimic and inhibitor, respectively; proliferation rate was assessed by CCK-8, apoptosis rate was tested by Annexin/PI and the expression levels of Bcl-XL, Bax, cyclin D2 and c-myc were examined by qPCR and western blot (WB). The levels of STAT3, p-STAT3, JAK2, and p-JAK2 were tested by WB. We found that BCR/ABL was inversely related to miR-451a and positively related to IL-6 in Ph+ ALL. MiR-451a inhibited the proliferation of SUP-B15 through the apoptosis pathway. The oncogene c-myc was down-regulated by miR-451a. We confirmed that miR-451a could target IL-6R and inhibit activation of JAK and STAT3. In conclusion, miR-451a is down regulated in Ph+ ALL and increasing the expression levels of miR-451a in leukemia cells can increase the potential of curing this disease.

Induction of Interleukin-10 in the Stable Transformants of Human T-Cell Line Expressing Epstein-Barr Virus-Encoded Small RNAs

Induction of Interleukin-10 in the Stable Transformants of Human T-Cell Line Expressing Epstein-Barr Virus-Encoded Small RNAs