Down-regulation Of Interleukin Research Articles

Effect of Hepatitis C virus proteins on the production of proinflammatory and profibrotic cytokines in Huh7.5 human hepatoma cells

Hepatitis C virus (HCV) is a widespread dangerous human pathogen. Up to 80% of HCV-infected individuals develop chronic infection, which is often accompanied by liver inflammation and fibrosis and, at terminal stages, liver cirrhosis and cancer. Treatment of patients with end-stage liver disease is often ineffective, and even patients with suppressed HCV replication have higher risk of death as compared with noninfected subjects. Therefore, investigating the mechanisms that underlie HCV pathogenesis and developing treatments for virus-associated liver dysfunction remain an important goal. The effect of individual HCV proteins on the production of proinflammatory and profibrotic cytokines in hepatocellular carcinoma Huh7.5 cells was analyzed in a systematic manner. Cells were transfected with plasmids encoding HCV proteins. Cytokine production and secretion was accessed by immunocytochemistry and ELISA of the culture medium, and transcription of the cytokine genes was assessed using reverse transcription and PCR. HCV proteins proved to differ in effect on cytokine production. Downregulation of interleukin 6 (IL-6) production was observed in cells expressing the HCV core, NS3, and NS5A proteins. Production of transforming growth factor β1 (TGF-β1) was lower in cells expressing the core proteins, NS3, or E1/E2 glycoproteins. A pronounced increase in production and secretion of tumor necrosis factor α (TNF-α) was observed in response to expression of the HCV E1/E2 glycoproteins. A higher biosynthesis, but a lower level in the cell culture medium, was detected for interleukin 1β (IL-1β) in cells harboring NS4 and IL-6 in cells expressing NS5В. The finding was possibly explained by protein-specific retention and consequent accumulation of the respective cytokines in the cell.

2,3',4,4',5-Pentachlorobiphenyl Induces Inflammatory Responses in the Thyroid Through JNK and Aryl Hydrocarbon Receptor-Mediated Pathway.

Polychlorinated biphenyls (PCBs) are durable and widely distributed environmental contaminants that can compromise the normal functions of multiple organs and systems; one important mechanism is the induction of inflammatory disorders. In this study, we explored the influences of 2,3',4,4',5-pentachlorobiphenyl (PCB118) on inflammatory responses and its underlying mechanisms in the thyroid. Wistar rats were administered PCB118 intraperitoneally at 0, 10, 100, and 1000 μg/kg/d, 5 days a week for 13 weeks; rat thyroid FRTL-5 cells were treated with PCB118 (0, 0.25, 2.5, and 25 nM) for indicated time. Results revealed that PCB118 promoted the generation of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and intercellular adhesion molecule-1 (ICAM-1) in a time- and dose-related manner and decreased sodium/iodide symporter (NIS) protein expression. Moreover, stimulation with PCB118 resulted in the upregulation of the aryl hydrocarbon receptor (AhR)-responsive gene cytochrome P450 1A1 in FRTL-5 cells; whereas pretreatment with the AhR inhibitor α-naphthoflavone or AhR small interfering RNA (siRNA) suppressed AhR, CYP1A1, IL-6, and ICAM-1 and restored NIS expression. Invivo and invitro studies also suggested that the c-Jun N-terminal kinase (JNK) pathway was activated on PCB118 exposure, and the experiments using siRNA for JNK partially blocked PCB118-induced upregulation of IL-6 and ICAM-1 and downregulation of NIS. Altogether, PCB118 stimulates production of IL-6, TNF-α, and ICAM-1 in the thyroid through AhR and JNK activations and subsequently interferes with NIS expression, resulting in the disruption of thyroid structure and function.

The role of the metastasis suppressor gene KAI1 in melanoma angiogenesis.

The tetraspan protein KAI1 (CD82) has been previously shown to have important roles in cell migration, invasion, and melanoma prognosis. In this study, we investigated the role of KAI1 regarding melanoma angiogenesis. KAI1 overexpression strongly suppressed the growth of the human umbilical vein endothelial cells and their tubular structure formation invitro. Also, KAI1 was able to inhibit both interleukin-6 (IL-6) and VEGF at mRNA and protein levels. Using nude mice in the invivo study, we showed that KAI1, through the regulation of ING4, inhibited blood vessel formation in matrigel plugs along with the downregulation of IL-6 and VEGF, and the recruitment of CD31-positive cells. Finally, we found that KAI1 was able to suppress the activity of a serine/threonine kinase Akt by suppressing Akt phosphorylation (Ser473). Taken together, our results suggested that KAI1 was able to suppress melanoma angiogenesis by downregulating IL-6 and VEGF expression, and the restoration of KAI1 functionality offered a new approach in human melanoma treatment.

Bioactive molecules in the <10kDa fraction of the Lactobacillus helveticus R0389 and Lactobacillus rhamnosus R0011 secretomes down-regulate IL-8 production by HT-29 human intestinal epithelial cells induced by pro-inflammatory stimuli (MUC9P.752)

Abstract The human gut microbiome has recently been associated with maintaining intestinal epithelial cell (IEC) homeostasis at the gastrointestinal interface by modulating host mucosal immune responses through varied mechanisms. The aim of this study was to compare the immunomodulatory activities of the L. helveticus R0389 and L. rhamosus R0011 secretomes on IEC. The human IEC line HT-29 was activated with a range of innate immune stimulants, to allow delineation of differential effects of the secretomes on Interleukin-8 (IL-8) production induced by varied stimuli. HT-29 IEC were co-incubated with either L. helveticus R0389 or L. rhamnosus R0011 secretomes and one of the following pro-inflammatory stimuli: interleukin 1-β (IL-1β), tumor necrosis factor-α (TNF-α); the toll-like receptor (TLR) agonists poly (I:C) (TLR3) or lipopolysaccharide (LPS) (TLR4), and alterations in IL-8 production were measured via enzyme-linked immunosorbant assay (ELISA). The L. helveticus R0389 and L. rhamnosus R0011 secretomes were also subjected to size fractionation to determine the size of the bioactive constituent of the secretome. Down-regulation of IL-8 was observed in HT-29 IEC co-incubated with the <10kDa fraction of the L. helveticus R0389 secretome or the L. rhamnosus R0011 secretome, for all of the innate immune stimulants tested. These results suggest that both Lactobacilli may secrete a low molecular weight bioactive molecule that modulates host immune activity by IEC.

Systemic gene transfer of binding immunoglobulin protein (BiP) prevents disease progression in murine collagen-induced arthritis.

Summary Recombinant human binding immunoglobulin protein (BiP) has previously demonstrated anti-inflammatory properties in multiple models of inflammatory arthritis. We investigated whether these immunoregulatory properties could be exploited using gene therapy techniques. A single intraperitoneal injection of lentiviral vector containing the murine BiP (Lenti-mBiP) or green fluorescent protein (Lenti-GFP) transgene was administered in low- or high-dose studies during early arthritis. Disease activity was assessed by visual scoring, histology, serum cytokine and antibody production measured by cell enzyme-linked immunosorbent assay (ELISA) and ELISA, respectively. Lentiviral vector treatment caused significant induction of interferon (IFN)-γ responses regardless of the transgene; however, further specific effects were directly attributable to the BiP transgene. In both studies Lenti-mBiP suppressed clinical arthritis significantly. Histological examination showed that low-dose Lenti-mBiP suppressed inflammatory cell infiltration, cartilage destruction and significantly reduced pathogenic anti-type II collagen (CII) antibodies. Lenti-mBiP treatment caused significant up-regulation of soluble cytotoxic T lymphocyte antigen-4 (sCTLA-4) serum levels and down-regulation of interleukin (IL)-17A production in response to CII cell restimulation. In-vitro studies confirmed that Lenti-mBiP spleen cells could significantly suppress the release of IL-17A from CII primed responder cells following CII restimulation in vitro, and this suppression was associated with increased IL-10 production. Neutralization of CTLA-4 in further co-culture experiments demonstrated inverse regulation of IL-17A production. In conclusion, these data demonstrate proof of principle for the therapeutic potential of systemic lentiviral vector delivery of the BiP transgene leading to immunoregulation of arthritis by induction of soluble CTLA-4 and suppression of IL-17A production.

Xiaotan Sanjie decoction inhibits interleukin-8-induced metastatic potency in gastric cancer.

To investigate the interaction between Xiaotan Sanjie (XTSJ) decoction and interleukin-8 (IL-8) and its effect on adhesion, migration and invasion of SGC-7901 gastric cancer cells. SGC-7901 gastric cancer cells were exposed to serum containing XTSJ decoction and/or IL-8 (1 ng/mL). SGC-7901 cell adhesion to fibronectin, an extracellular matrix component, was detected using the Cell Counting Kit-8. Migration and invasion abilities of SGC-7901 cells were detected by scratch wound and Transwell chamber assays. Then, protein (immunofluorescence and Western blot) and mRNA levels (quantitative polymerase chain reaction) of cluster of differentiation 44 (CD44), a cell adhesion molecule, were measured in 72-h-cultured SGC-7901 cells. Cell adhesion was promoted by IL-8 (P = 0.001), but was inhibited by XTSJ decoction (P = 0.0001). Similarly, IL-8 promoted SGC-7901 cell invasion (P = 0.003), and XTSJ decoction inhibited cell invasion (P = 0.001). IL-8 induced SGC-7901 cell migration, but this was inhibited by XTSJ decoction. IL-8 up-regulated CD44 protein (P = 0.028) and mRNA expression (P = 0.002), whereas XTSJ decoction inhibited CD44 protein expression (P = 0.0001), but not mRNA expression (P = 0.275). An interaction between XTSJ decoction and IL-8 was confirmed in the invasion (P = 0.001) and CD44 mRNA expression of SGC-7901 cells (P = 0.010), but not in cell adhesion (P = 0.051). XTSJ decoction may inhibit adhesion, migration and invasion of gastric cancer cells, which is partly associated with down-regulation of IL-8.

Hepatotoxicants induce cytokine imbalance in response to innate immune system

In recent years, attention has been paid to innate immune systems as mechanisms to initiate or promote drug-induced liver injury (DILI). Kupffer cells are hepatic resident macrophages and might be involved in the pathogenesis of DILI by release of pro- and anti-inflammatory mediators such as cytokines, chemokines, reactive oxygen species, and/or nitric oxides. The purpose of this study was to investigate alterations in mediator levels induced by hepatotoxic compounds in isolated Kupffer cells and discuss the relation between balance of each cytokine or chemokine and potential of innate immune-mediated DILI. Primary cultured rat Kupffer cells were treated with hepatotoxic (acetaminophen, troglitazone, trovafloxacin) or non-hepatotoxic (pioglitazone, levofloxacin) compounds with or without lipopolysaccharide (LPS). After 24 hr treatment, cell supernatants were collected and various levels of mediators released by Kupffer cells were examined. Although hepatotoxicants had no effect on the LPS-induced tumor necrosis factor-alpha (TNF-α) secretion, they enhanced the release of pro-inflammatory cytokine interleukin-1 beta (IL-1β) and suppressed the anti-inflammatory cytokines interleukin-6 (IL-6) and interleukin-10 (IL-10) induced by LPS. These cytokine shifts were not associated with switching the phenotypes of M1 and M2 macrophages in Kupffer cells. In conclusion, the present study suggested that the levels of some specific cytokines are affected by DILI-related drugs with LPS stimulation, and imbalance between pro- and anti-inflammatory cytokines, induced by the up-regulation of IL-1β and the down-regulation of IL-6 or IL-10, plays a key role in innate immune-mediated DILI.

Endostatin improves cancer-associated systemic syndrome in a lung cancer model.

Cancer-associated systemic syndrome (CASS) is characterized by a constellation of symptoms, including progressive weight loss, anemia, endocrine disorders, gastrointestinal dysfunction, muscle and adipose atrophy, hepatic peliosis and kidney failure. The present study assesses the effects of endostatin on CASS and any possible underlying mechanism in tumor-bearing mice. The results showed that the inoculation of Lewis lung carcinoma cells into mice led to CASS that was characterized by a notable decrease in body weight, severe anemia phenotype, disordered biochemistry, hepatosplenomegaly, and a marked increase in serum vascular endothelial growth factor (VEGF), tumor necrosis factor α and interleukin-6 (IL-6). The continuous injection of 10 mg/kg/day endostatin suppressed tumor growth and alleviated CASS in the tumor-bearing mice, as shown by weight gain, improvement in biochemistry and anemia, and the preservation of organ function. The effects of endostatin on CASS in the tumor-bearing mice were accompanied by the downregulation of serum VEGF and IL-6. Collectively, these findings indicate that endostatin improves CASS in tumor-bearing mice by decreasing the serum levels of VEGF and IL-6.

Downregulation of IL6 Targeted MiR-376b May Contribute to a Positive IL6 Feedback Loop During Early Liver Regeneration in Mice

Background/Aims: MicroRNAs (miRNAs) are a group of endogenous, small, noncoding RNAs implicated in a variety of biological processes, including cell proliferation, apoptosis, differentiation and metabolism. The present study aims to explore the potential role and molecular mechanism of miR-376b during the early phase of liver regeneration. Methods: MiRNA profiling microarrays were used to assess the changes in miRNA expression. For functional analysis, cell proliferation, apoptosis assays, real time quantitative PCR and westernblot analysis were performed. Results: The comprehensive miRNA expression profiling assays on regenerating liver tissues 4 h after partial hepatectomy (PH) showed that three miRNAs (miR-127, miR-376b and miR-494) located in the Dlk1-Gtl2 miRNA cluster were significantly downregulated. In vitro functional studies demonstrated that high-level interleukin 6 (IL6) inhibited the expression of miR-376b, and miR-376b mimics treatment decreased cell proliferation and increased apoptosis. Further target analysis showed that miR-376b reduced the mRNA and protein expression levels of NF-kappa-B inhibitor zeta (NFKBIZ) and signal transducers and transcription activators 3 (STAT3). Additionally, IL6-induced miR-376b downregulation would, in turn, increase the expression of IL-6 possibly via a feedback loop involving NFKBIZ or/and STAT3. Conclusion: During the early phase of liver regeneration, miR-376b expression was significantly decreased. Our findings reveal that a regulatory circuitry between miR-376b and IL-6 may exist, which trigger the initiation of liver regeneration.

Integrative analysis of differential miRNA and functional study of miR-21 by seed-targeting inhibition in multiple myeloma cells in response to berberine.

BackgroundBerberine is a natural alkaloid derived from a traditional Chinese herbal medicine. It is known to modulate microRNA (miRNA) levels, although the mechanism for this action is unknown. Here, we previously demonstrate that the expression of 87 miRNAs is differentially affected by berberine in multiple myeloma cells. Among 49 miRNAs that are down-regulated, nine act as oncomirs, including miR-21. Integrative analysis showed that 28 of the down-regulated miRNAs participate in tumor protein p53 (TP53) signaling and other cancer pathways. miR-21 is involved in all these pathways, and is one of the most important oncomirs to be affected by berberine in multiple myeloma cells.ResultsWe confirmed that berberine down-regulated miRNA-21 expression and significantly up-regulated the expression of programmed cell death 4 (PDCD4), a predicted miR-21 target. Luciferase reporter assays confirmed that PDCD4 was directly regulated by miR-21. Bioinformatic analysis revealed that the miR-21 promoter can be targeted by signal transducer and activator of transcription 3 (STAT3). Down-regulation of interleukin 6 (IL6) by berberine might lead to inhibition of miR-21 transcription through STAT3 down-regulation in multiple myeloma. Furthermore, both berberine and seed-targeting anti-miR-21 oligonucleotide induced apoptosis, G2-phase cell cycle arrest and colony inhibition in multiple myeloma cell lines. Depletion of PDCD4 by short interfering RNA could rescue berberine-induced cytotoxicity in multiple myeloma cells.ConclusionsOur results suggest that berberine suppresses multiple myeloma cell growth, at least in part, by down-regulating miR-21 levels possibly through IL6/STAT3. This led to increased PDCD4 expression, which is likely to result in suppression of the p53 signaling pathway. These findings may also provide new mechanistic insight into the anti-cancer effects of certain compounds in traditional Chinese herbal medicines.

Long-term effect of curcumin down-regulates expression of tumor necrosis factor-α and interleukin-6 via modulation of E26 transformation-specific protein and nuclear factor-κB transcription factors in livers of lymphoma bearing mice

Tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) are typical multifunctional proinflammatory cytokines involved actively in the regulation of immunity, hematopoiesis, inflammation and carcinogenesis. Coordinated regulation of these cytokines could be required for effective regulation of early phase inflammation and cancer progression. The present work was aimed to analyze the anti-carcinogenic action of curcumin on the expression of TNF-α and IL-6 even after withdrawal of treatment. Up-regulated expressions of TNF-α and IL-6 in terms of mRNA and protein levels in lymphoma bearing mice were significantly down-regulated by curcumin as compared to normal. Electrophoretic mobility shift assay (EMSA) results revealed that curcumin reduced binding of nuclear protein with ETS and NF-κB binding elements of TNF-α and IL-6 promoters, respectively. The anti-carcinogenic effect of curcumin against lymphoma progression has been reported previously. In continuation, the present study suggests that the long-term effect of curcumin may contribute to attenuate cancer progression via the down-regulation of TNF-α and IL-6 modulated by E26 transformation-specific protein (ETS) and nuclear factor-κB (NF-κB), respectively.

NLRC5 Mediates Cytokine Secretion in RAW264.7 Macrophages and Modulated by the JAK2/STAT3 Pathway

The nucleotide-binding domain leucine-rich repeat proteins (NLRs), a class of innate immune receptors that respond to pathogen attack or cellular stress, have gained increasing attention. NLRC5 is the largest member of NLR family, which has recently been identified as a critical regulator of immune responses. In this study, we explore the role of NLRC5 in cytokine secretion and the role of the JAK2/STAT3 signaling pathway in lipopolysaccharide-induced NLRC5 expression in RAW264.7 cells. We demonstrated that overexpression of NLRC5 results in a downregulation of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) secretion; on the other hand, knockdown of NLRC5 by transfecting siRNA enhanced IL-6 and TNF-α secretion in RAW264.7 cells. These results indicated that NLRC5 plays a negative role in the regulation of IL-6 and TNF-α. Meanwhile, AG490 (a specific inhibitor of the JAK2/STAT3 signaling pathway) and JAK2 siRNA were used to manipulate JAK2/STAT3 activity. Finally, the results showed that AG490 and JAK2 siRNA inhibited NLRC5 expression and the expression levels of p-JAK2 and p-STAT3. We, for the first time, demonstrate that the inhibition of the JAK2/STAT3 signaling pathway results in decrease of NLRC5 expression.

Controversial issues regarding the roles of IL-10 and IFN-γ in active/inactive chronic hepatitis B.

According to the important roles played by cytokines in induction of appropriate immune responses against hepatitis B virus (HBV), Dimitropoulou et al have examined the important cytokines in their patients. They showed that the serum levels of interleukin 10 (IL-10) and interferon-γ (IFN-γ) were decreased in patients with HBeAg-negative chronic active hepatitis B compared with the inactive hepatitis B virus carriers (Dimitropoulou et al 2013). The controversy can be considered regarding the decreased serum levels of IFN-γ in the HBeAg-negative chronic active hepatitis B patients. They concluded that subsequent to decreased expression of IFN-γ, the process of HBV proliferation led to liver diseases. Previous studies stated that HBV is not directly cytopathic for the infected hepatocytes and immune responses are the main reason for destruction of hepatocytes (Chisari et al, 2010). Scientists believe that immune responses against HBV are stronger in active forms of chronic HBV infected patients than inactive forms (Zhang et al, 2012). Therefore, the findings from Dimitropoulou et al may deserve further attention and discussion. Additionally, downregulation of IL-10 in chronically active hepatitis B infected patients has also confirmed our claim. IL-10 is an anti-inflammatory cytokine and its expression is increased in inactive forms in order to downregulate immune responses (Arababadi et al, 2012). Thus, based on the results from Dimitropoulou et al, it can be concluded that increased immune responses in chronically active hepatitis B infected patients are related to declined expression of IL-10 and interestingly IFN-γ is not involved in induction of immune responses in these patients.

Effect of PilE4 of Francisella tularensis subsp. holarctica (live vaccine strain) to brain endothelium

Francisella are rare, highly infectious vector-borne bacteria, which infect more than 250 host species, including humans. Francisella are able to invade multiple organs in the host body, such a skin, liver, lung and central nervous system. To invade various organs, Francisella have to cross the cell linings like endothelial barriers. Interaction with endothelial cells is multistage process, which includes adhesion and activation of signaling events. Our previous work has shown that Francisella tularensis subsp. holarctica Live Vaccine Strain (LVS) interacts and adhere to endothelial cells through PilE4 and Intercellular adhesion molecule 1(ICAM-1) interaction. To corroborate consequences of PilE4 adhesion to endothelial cells, we incubated brain microvascular endothelial cells with recombinant PilE4 protein and assessed the regulation of several genes with qRT-PCR. Results showed that PilE4 upregulated the expression of adhesion molecules (ICAM-1 and PECAM-1), matrix metalloproteases (MMP 1, MMP 3 and MMP 9) and molecules that are involved in pathogen recognition (TLR-6, MyD88, IRAK-1 and TRAF-6) in brain endothelium. On the other hand, we found down regulation of interleukins and NF-kB. Inhibition of NF-kB indicates that Francisella might use NF-kB subversion mechanism to evade immune response. This mechanism is described in other pathogens such as Listeria and Yersinia. Previous studies have showed that matrix-metalloprotases, mainly MMP-9, is crucial to disrupt cytoskeleton of brain endothelium to increase the permeability of BBB. In summary, work reveal hidden aspects of invasion and translocation of Francisella across the brain endothelium, that offers new insight into the pathobiology of neuroinvasion of Francisella.

Downregulation of IL-8, ECP, and total IgE in the tears of patients with atopic keratoconjunctivitis treated with rebamipide eyedrops.

Rebamipide eyedrops are approved in Japan for the treatment of dry eye disease. Some patients with allergic conjunctival diseases also manifest dry eye. Earlier we reported that rebamipide suppressed polyI:C-induced inflammatory cytokines in human conjunctival epithelial cells. In the current study we examined the effect of rebamipide eyedrops on the level of interleukin-8 (IL-8), eosinophil cationic protein (ECP), and total IgE on the ocular surface.We prescribed rebamipide eyedrops to patients with atopic keratoconjunctivitis (AKC) who presented with dry eye (6 eyes in 4 AKC patients) and measured the IL-8, ECP, and total IgE levels in their tears before- and 2, and 4–6 weeks after the start of rebamipide treatment. To measure the IL-8 and total IgE levels in their tears we used BD™ CBA Flex sets; ECP measurements were with ELISA. The level of IL-8, ECP, and total IgE in the tears of AKC patients was reduced significantly 4–6 weeks after the start of rebamipide treatment. We also recorded subjective symptoms associated with AKC, e.g. itching, foreign body sensation, and eye mucus discharge, by using a patient questionnaire. Their subjective symptoms associated with AKC were also significantly ameliorated at 2 and 4–6 weeks.Our observations suggest that the anti-inflammatory effects of rebamipide eyedrops help to combat human ocular surface inflammation and that they may be a new effective therapy in patients with AKC.Electronic supplementary materialThe online version of this article (doi:10.1186/2045-7022-4-40) contains supplementary material, which is available to authorized users.

Knockdown of TrkA in cumulus oocyte complexes (COCs) inhibits EGF-induced cumulus expansion by down-regulation of IL-6

Tyrosine kinase receptor A (TrkA), the high-affinity receptor of nerve growth factor (NGF), is known to play key roles in ovarian follicular development, such as assembly of early follicles and follicular ovulation. However, little is known about the roles of TrkA in cumulus oocyte complex (COC) expansion. In this study, we found that TrkA was abundant in large antral follicles and knockdown of TrkA in COCs attenuated epidermal growth factor (EGF)-induced COC expansion and further decreased the ovulation rate. The effect of TrkA on COC expansion was not mediated through downstream EGF effectors, phosphorylation of extracellular regulated protein kinases 1/2 (ERK1/2) or drosophila mothers against decapentaplegic protein (SMAD), or through up-regulation of COC expansion-related transcripts such as prostaglandin-endoperoxide synthase 2 (Ptgs2), hyaluronan synthase 2 (Has2), TNF-induced protein 6 (Tnfaip6) or pentraxin 3 (Ptx3). However, pharmacological blockade of TrkA transducing activity (K252α) in COCs decreased the mRNA expression and protein secretion of interleukin-6 (IL-6), identified from mRNA microarray of K252α-treated COCs. Meanwhile, knockdown of IL-6 attenuated EGF-induced COC expansion. In addition, IL-6 rescued the inhibitory effect of K252α on EGF-induced cumulus expansion. Therefore, IL-6 may act as a new potential cumulus expansion-related transcript, which may be involved in the integration of TrkA and EGF signaling in affecting COC expansion. Here, we provide mechanistic insights into the roles of TrkA in EGF-induced cumulus expansion. Understanding potential cross-points between TrkA and EGF affecting cumulus expansion will help in the discovery of new therapeutic targets in ovulation-related diseases.

Downregulation of IL7R, CCR7, and TLR4 in the Cord Blood of Children With Respiratory Syncytial Virus Disease

The association between gene expression at birth of 11 candidate genes with important innate and adaptive immune functions and later respiratory syncytial virus (RSV) disease was investigated. Cord blood was collected from 2108 newborns. Forty-seven were subsequently RSV positive. Gene expression analysis by quantitative reverse transcription-polymerase chain reaction was compared to 17 controls. There was downregulation of interleukin 7 receptor (IL7R) (P = .0001) and chemokine receptor 7 (CCR7) (P = .002), and in the severe disease subcategory, downregulation of Toll-like receptor 4 (TLR4) (P = .003). IL7R and CCR7 facilitate communication between adaptive and innate immune systems. TLR4 activates the innate immune system on RSV exposure. Delayed innate and adaptive immune activation may predispose children to more severe RSV disease.

Interleukin‐6 downregulation with mesenchymal stem cell differentiation results in loss of immunoprivilege

Allogeneic mesenchymal stem cell (MSC) transplantation improves cardiac function, but cellular differentiation results in loss of immunoprivilege and rejection. To explore the mechanism involved in this immune rejection, we investigated the influence of interleukin-6 (IL-6), a factor secreted by MSCs, on immune privilege after myogenic, endothelial and smooth muscle cell differentiation induced by 5-azacytidine, VEGF, and transforming growth factor-β (TGF-β), respectively. Both RT-PCR and ELISA showed that myogenic differentiation of MSCs was associated with significant downregulation of IL-6 expression (P < 0.01), which was also observed following endothelial (P < 0.01) and smooth muscle cell differentiation (P < 0.05), indicating that IL-6 downregulation was dependent on differentiation but not cell phenotype. Flow cytometry demonstrated that IL-6 downregulation as a result of myogenic differentiation was associated with increased leucocyte-mediated cell death in an allogeneic leucocyte co-culture study (P < 0.01). The allogeneic reactivity associated with IL-6 downregulation was also observed following MSC differentiation to endothelial and smooth muscle cells (P < 0.01), demonstrating that leucocyte-mediated cytotoxicity was also dependent on differentiation but not cell phenotype. Restoration of IL-6 partially rescued the differentiated cells from leucocyte-mediated cell death. These findings suggest that rejection of allogeneic MSCs after implantation may be because of a reduction in cellular IL-6 levels, and restoration of IL-6 may be a new target to retain MSC immunoprivilege.

Interleukin-8 as a modulator of response to bevacizumab in preclinical models of head and neck squamous cell carcinoma

Bevacizumab, a monoclonal antibody to VEGF-A, is under active clinical evaluation in head and neck squamous cell carcinoma (HNSCC) and appears to be a promising therapy in at least a subset of patients. However, there are no reliable predictive biomarkers to identify those patients most likely to benefit. In this study, we assessed the efficacy of bevacizumab in HNSCC xenograft models to characterize escape mechanisms underlying intrinsic resistance and identify potential biomarkers of drug response. We evaluated the angiogenic profile of HNSCC cells from sensitive and resistant cell lines using antibody array. We further examined the role of interleukin-8 (IL-8) in contributing to resistance both in vitro and in vivo, using a loss- and gain-of-function approach. Angiogenic profiling indicated that resistant cells expressed higher levels of proangiogenic factors including IL-8, interleukin-1α (IL-1α), vascular endothelial growth factor (VEGF), fibroblast growth factor-a (FGF-a), and tumor necrosis factor-α (TNF-α). IL-8 was the most differentially expressed protein. IL-8 signaling compensated for VEGF inhibition in endothelial cells. Downregulation of IL-8 resulted in sensitization of resistant tumors to bevacizumab by disrupting angiogenesis and enhancing endothelial cell apoptosis. Overexpression of IL-8 in sensitive tumors conferred resistance to bevacizumab. Serum analysis of HNSCC patients treated with a bevacizumab-containing regime revealed high baseline IL-8 levels in a subset of patients refractory to treatment but not in responders. These results implicate IL-8 in mediating intrinsic resistance to bevacizumab in HNSCC. Hence, co-targeting of VEGF and IL-8 may help overcome resistance and enhance therapeutic efficacy.

Opposite effect of angiotensin receptor blockade on CXCL8 production and CXCR1/2 expression of angiotensin II-treated THP-1 monocytes

Interleukin-8 (IL-8) or CXCL8 is a potent chemotactic factor that is involved in atherogenesis. IL-8 mediates its pre-inflammatory effects through interaction with CXCR1 and CXCR2. In the present study, we investigated the effects of angiotensin II (Ang II) on IL-8 synthesis and CXCR1/CXCR2 expression of THP-1 monocytes. IL-8 was measured in the culture medium using ELISA. Expression of chemokine receptors CXCR1 and CXCR2 was evaluated by flow cytometry. Results demonstrated that the addition of Ang II increased IL-8 production in the THP-1 monocytes. The Ang II type 1 receptor blocker (ARB) losartan significantly blocked Ang II-induced IL-8 production. Notably, losartan blocked LPS-induced IL-8 production by THP-1 monocytes and produced a small but statistically significant reduction of baseline IL-8 production of naïve THP-1 cells. Losartan also produced a statistically significant increase of fluorescence intensity of naïve CXCR1- and CXCR2-positive THP-1 monocytes, probably as a negative feedback effect secondary to IL-8 downregulation. In conclusion, we demonstrated that Ang II increased IL-8 production by THP-1 monocytes. Losartan significantly suppressed the latter effect, suggesting an AT-1 mediated pathway. Moreover, losartan suppressed the IL-8 production of naïve THP-1 monocytes and LPS-treated THP-1 monocytes, suggesting a broader spectrum of pleiotropic effects. Extrapolating this in vitro observation to in vivo pathways, we propose Ang II-induced IL-8 production by monocytes as another pre-atherogenic potential of Ang II that can be effectively blocked by the AT1 receptor blockade.