Effects Of Interleukin-6 Research Articles

Abstract B52: 2-in-1 “sniper” nanomedicines rescue dendritic cells by two pronged inhibition of JAK2/STAT-3 and p38 MAPK pathways

Abstract Immunotherapy has stolen the spotlight as one of the most promising therapeutic strategies for many late stage cancers. Despite exhibiting immense potential, dendritic cell (DC) based immunotherapy has shown limited clinical benefits owing to the antagonistic effects of regulatory T cells. While regulatory T-cells dampen the immune response elicited by T effector cells through known control mechanisms, they also constitute an immune suppressive milieu with several other tumor-derived factors that impair the development and maturation of dendritic cells. This serves as a mechanism for the tumor cells to escape immune surveillance and control. It is well known that inhibition of the JAK2/STAT-3 and p38 MAPK pathways in DCs negates the tumor-induced suppression of their maturation. But it has been shown that inhibition of the STAT-3 pathway alone could counteract the suppressive effects of Interleukin-6 only and inhibition of the p38 MAPK pathway in cancer cells can be counterproductive as it is important for apoptosis. Thus it becomes essential that, to achieve a superior therapeutic response it is imperative to couple the inhibition of STAT-3 along with p38 MAPK pathway and to also ensure that it is targeted towards dendritic cells of the tumor microenvironment. We have catered to these necessities in this study by proposing a novel, supramolecular 2-in-1 nanomedicine designed by the self-assembly of patient compatible lipids that houses a STAT-3 inhibitor and a p38-α inhibitor , thus ensuring the deterministic delivery of both the drugs in a spatially constrained manner. We have shown that the 2-in-1 nanomedicine achieves superior efficacy by releasing both the drugs in a sustained manner during the differentiation of DCs and hence upregulates dendritic cell maturation markers like CD80, CD86 and MHC II. More importantly we aim to program the drug-loaded nanoparticles for selective uptake by dendritic cells of the tumor milieu. In a separate experiment we have shown that dendritic cells favor the uptake of nanoparticles with specific surface charges both in vitro and in vivo in B16F10 mouse melanoma model. Thus we conclude that the proposed 2-in-1 “sniper” nanoparticle can contribute immensely towards a targeted immunotherapy approach for rescuing dendritic cells from immune suppression in aggressive cancers like melanoma. Note: This abstract was not presented at the conference. Citation Format: Siva Kumar Natarajan, Vineethkrishna Chandhrasekar, Noha Ismail, Sharada Swaminathan, Shiladitya Sengupta, Ashish Kulkarni. 2-in-1 “sniper” nanomedicines rescue dendritic cells by two pronged inhibition of JAK2/STAT-3 and p38 MAPK pathways. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr B52.

Immature granulocytes predict severe acute pancreatitis independently of systemic inflammatory response syndrome

IntroductionEarly prediction of severity of acute pancreatitis (AP) by a simple parameter that positively correlates with the activation stage of the immune system would be very helpful because it could influence the management and improve the outcome. Tumor necrosis factor α (TNF-α) and interleukin-1 (IL-1) play a critical role in the pathogenesis systemic inflammatory response syndrome (SIRS) and severity of AP. One of the effects of IL-1 and TNF-α is an increase in the number of immature granulocytes (IGs) in the peripheral blood.AimTo assess whether the IGs% in plasma could be an independent marker of AP severity.Material and methodsA cohort of 77 patients with AP were prospectively enrolled in the study. The IGs were measured from whole blood samples obtained from the first day of hospitalization using an automated analyser.ResultsWe observed 44 (57%) patients with mild AP, 21 (27%) patients with moderate severe AP (SAP) and 12 (16%) patients with SAP. The cut-off value of IGs was 0.6%. The IGs > 0.6% had a sensitivity, specificity, and positive and negative predictive value of 100%, 96%, 85.7%, and 100%, respectively (area under the curve (AUC) = 0.98). On admission, SIRS was present in 25 (32%) patients. We found that in patients who fulfilled at least two criteria for SIRS, SAP could be predicted with 75% sensitivity and 75.4% specificity, positive predictive value 36%, negative predictive value 94.2%.ConclusionsThe IGs% as a routinely obtained marker appears to be a promising, independent biomarker and a better predictor of early prognosis in SAP than SIRS and white blood cell.

Epac activation inhibits IL-6-induced cardiac myocyte dysfunction

Pro-inflammatory cytokines are released in septic shock and impair cardiac function via the Jak-STAT pathway. It is well known that sympathetic and thus catecholamine signaling is activated thereafter to compensate for cardiac dysfunction. The mechanism of such compensation by catecholamine signaling has been traditionally understood to be cyclic AMP-dependent protein kinase (PKA)-mediated enforcement of cardiac contractility. We hypothesized that the exchange protein activated by cAMP (Epac), a newly identified target of cAMP signaling that functions independently of PKA, also plays a key role in this mechanism. In cultured cardiac myocytes, activation of Epac attenuated the inhibitory effect of interleukin-6 on the increase of intracellular Ca2+ concentration and contractility in response to isoproterenol, most likely through inhibition of the Jak-STAT pathway via SOCS3, with subsequent changes in inducible nitric oxide synthase expression. These findings suggest a new role of catecholamine signaling in compensating for cardiac dysfunction in heart failure. Epac and its downstream pathway may be a novel target for treating cardiac dysfunction in endotoxemia.

Interleukin-1 receptor (IL-1R) mediates epilepsy-induced sleep disruption.

BackgroundSleep disruptions are common in epilepsy patients. Our previous study demonstrates that homeostatic factors and circadian rhythm may mediate epilepsy-induced sleep disturbances when epilepsy occurs at different zeitgeber hours. The proinflammatory cytokine, interleukin-1 (IL-1), is a somnogenic cytokine and may also be involved in epileptogenesis; however, few studies emphasize the effect of IL-1 in epilepsy-induced sleep disruption. We herein hypothesized that IL-1 receptor type 1 (IL-1R1) mediates the pathogenesis of epilepsy and epilepsy-induced sleep disturbances. We determined the role of IL-1R1 by using IL-1R1 knockout (IL-1R1 −/− KO) mice.ResultsOur results elucidated the decrease of non-rapid eye movement (NREM) sleep during the light period in IL-1R −/− mice and confirmed the somnogenic role of IL-1R1. Rapid electrical amygdala kindling was performed to induce epilepsy at the particular zeitgeber time (ZT) point, ZT13. Our results demonstrated that seizure thresholds induced by kindling stimuli, such as the after-discharge threshold and successful kindling rates, were not altered in IL-1R −/− mice when compared to those obtained from the wildtype mice (IL-1R +/+ mice). This result suggests that IL-1R1 is not involved in kindling-induced epileptogenesis. During sleep, ZT13 kindling stimulation significantly enhanced NREM sleep during the subsequent 6 h (ZT13-18) in wildtype mice, and sleep returned to the baseline the following day. However, the kindling-induced sleep alteration was absent in the IL-1R −/− KO mice.ConclusionsThese results indicate that the IL-1 signal mediates epilepsy-induced sleep disturbance, but dose not participate in kindling-induced epileptogenesis.

Effects of interleukin-6, interleukin-18, and statin use, evaluated at acute stroke, on post-stroke depression during 1-year follow-up

Proinflammatory cytokines are associated with the development of post-stroke depression (PSD). Statins are thought to possess anti-inflammatory properties but their interactions with cytokines regarding the risk of PSD have yet to be investigated. Thus, the present study aimed to determine whether interleukin (IL)-6 and IL-18 were associated with the development of depression at 2 weeks and 1year after stroke using a longitudinal post-stroke cohort. Furthermore, this study examined the potential interactions between statin use and cytokines on PSD. For this study, 286 patients were evaluated 2 weeks after stroke and 222 patients were followed-up 1year later. Depression was diagnosed using criteria from the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV) and then categorized into no PSD or any PSD, which included diagnoses of both major and minor depression. The effects of IL-6 and IL-18 on PSD as well as their interaction with a statin at both examination time-points were investigated using a multivariate logistic regression model. Higher IL-6 and IL-18 levels were independently associated with depressive disorders within 2 weeks and at 1year after stroke. When stratified by statin use, these significant associations were more evident in patients who did not use a statin. Furthermore, there was a significant interaction between statin use and IL-6 on the presence of a depressive disorder at 1year. The present findings support the cytokine hypothesis of PSD and indicate that the preventive effects of statin use against PSD may be mediated by its interactions with IL-6.

A method to induce Interleukin-1 Receptor Antagonist Protein from autologous whole blood

ObjectiveCurrent orthopedic therapies, aimed solely at symptomatic control, are unable to restore the cytokine imbalance that produces the hallmark clinical profile of osteoarthritis. While a myriad of chemical factors in the cytokine network stimulate local joint inflammation and pain, Interleukin 1 (IL-1) is widely recognized as a key offender and a potential therapeutic target. The purpose of this article is to describe a novel, on-site, point of service process (Arthrokinex™) to induce Interleukin 1 Receptor Antagonist Protein (IL-1-Ra or IRAP) from whole blood aimed at inhibiting the destructive intra-articular effects of IL-1. Methods53 patient charts were included in this retrospective chart review study. Venous blood from the selected participants had been harvested and centrifuged to isolate Platelet Rich Plasma and Platelet Poor Plasma. These layers were extracted and incubated for 30min in a specialized syringe containing medical grade concentrator beads. After centrifuge filtration, the supernatant containing IL-1-Ra was extracted. Anti-inflammatory (IL-1-Ra, IL-10) and pro-inflammatory (TNF α, IL-1 β) cytokines of baseline whole blood were compared to the conditioned serum following quantification using ELISA. ResultsOn average, a 32-fold increase (baseline, 550pg/mL; post conditioning 17,537pg/mL) in IL-1-Ra concentration was observed after the brief interaction of blood with the concentrator bead surface. IL-1-Ra, if present in concentrations that are 10–100 times higher than IL-1β, will block the interaction of IL-1β with cell surface receptors. At these increased concentrations, Arthrokinex™ induced IL-1-Ra joint injections produce an IL-1-Ra to IL-1β ratio of 999:1. Post conditioning levels of IL-1β and TNF α were not clinically significant. ConclusionThe Arthrokinex™ blood conditioning process has the ability to rapidly induce IL-1-Ra without increasing the pro-inflammatory cytokine profile.

Brain endothelial IL-1R1 mediates central IL-1 induced neuroinflammation and anxiety-like behavior

Interleukin-1 (IL-1) mediates diverse neuropathological effects and behavioral changes in the central nervous system (CNS) through type I IL-1 receptor (IL-1R1). Different CNS cell types are known to mediate different IL-1 effects. In this study, we investigated IL-1 induced neuroinflammation and anxiety using three cell-type specific IL-1R1 expressing mouse lines: Tie2Cre-IL-1R1r/r (IL-1R1 restricted to endothelial cells and hematopoietic cells), LysMCre-IL-1R1r/r (myeloid cells) or HipAAV2Cre-IL-1R1r/r (hippocampal neurons). Following intracerebroventricular (ICV) IL-1 injection microglial activation was induced in all three mouse lines but with distinct morphological characteristics. Microglia in Tie2Cre-IL-1R1r/r mice developed most abundant branches and longest processes length. Cytokine expression analysis showed microglia in wild-type (WT) and Tie2Cre-IL-1R1r/r mice upregulated proinflammatory cytokines IL-1 β and TNF- α , which did not occur in LysMCre-IL-1R1 and AAVCre-IL-1R1 mice which lacked endothelial IL-1R1. We then adoptively transferred SVEC4-10 cells, an IL-1R1 expressing endothelial cell line, into striatum of IL-1R1 knockout mice (IL-1R1r/r). After the transfer, microglial activation was induced by ICV IL-1 but not by saline, indicating endothelial IL-1R1 is sufficient to mediate inflammatory microglial activation. Furthermore, we found endothelial IL-1R1 dependent microglial activation was mediated via exocytosis of danger signals such as ATP. In addition, anxiety-like behavior developed in WT and Tie2Cre-IL-1R1r/r mice but not LysMCre-IL-1R1r/r or AAV2Cre-IL-1R1r/r lines. Collectively, these findings demonstrate that brain endothelial IL-1R1 mediates central IL-1 induced neuroinflammation and anxiety-like behavior.

Additive/Synergistic Effects of Interleukin-6 and Interleukin-10 on the Proliferation of Human Myeloma Cells

Multiple myeloma (MM) is a haematological disorder of malignant plasma cells. Interleukin-6 (IL-6) is a major proliferative factor for the malignant plasma cells. Interleukin-10 (IL-10) is an Interleukin-6 related growth factor for multiple myeloma cells. Aim: (1) to investigate the combination treatment with IL-6 and IL-10 on the proliferation in human myeloma cells, (2) to investigate the uptake of exogenous IL-6 by cultivated myeloma cells. Materials and Methods: Four human multiple myeloma cell lines were investigated in an in vitro model. Parameters: Viability, Cytokine production, Membrane expressions of IL-6 receptor and IL-10 receptor, Cell proliferation. Results: IL-6 increased the production of IL-10 (spontaneous: ND-79, induced up to 939 pg/ml). Both cytokines enhanced the proliferation in all cell lines. The proliferation rate for IL-6 lay between 120-138%, for IL-10 between 116-128%. The combination of 1L-6 with IL-10 led to additive/synergistic effects in the proliferation of myeloma cells. IL-6 increased its receptor up to 192%. The up-regulation of the IL-10 receptor by IL-6 was less (110-129%). After 1 hour of incubation already 62-76 % of exogenous IL-6 was taken into the cells. At 24 hours the uptake of IL-6 was 84-90%. Conclusion: The additive/synergistic effects of IL-6 and IL-10 have an important value in the treatment of multiple myeloma. The key position of the complex IL-6/IL-6R gives reasons for a specific- targeted therapy with new perspectives for the future: When the cytokine1 induces the synthesis of cytokine2 leading to enhanced cell-proliferation then by the inhibition of cytokine1 the effect of cytokine2 also will be abolished.

MicroRNA-146a reduces IL-1 dependent inflammatory responses in the intervertebral disc

Because miR-146a expression in articular chondrocytes is associated with osteoarthritis (OA), we assessed whether miR-146a is linked to cartilage degeneration in the spine. Monolayer cultures of nucleus pulposus (NP) cells from the intervertebral discs (IVD) of bovine tails were transfected with a miR-146a mimic. To provoke inflammatory responses and catabolic extracellular matrix (ECM) degradation, cells were co-treated with interleukin-1 (IL-1). Transfection of miR-146a decreases IL-1 induced mRNA levels of inflammatory genes and catabolic proteases in NP cells based on quantitative real-time reverse transcriptase PCR (qRT-PCR) analysis. Similarly, miR146a suppresses IL-1 induced protein levels of matrix metalloproteinases and aggrecanases as revealed by immunoblotting. Disc segments from wild type (WT) and miR-146a knockout (KO) mice were cultured ex vivo in the presence or absence of IL-1 for 3days. Histological and immuno-histochemical (IHC) analyses of disc organ cultures revealed that IL-1 mediates changes in proteoglycan (PG) content and in-situ levels of catabolic proteins (MMP-13 and ADAMTS-5) in the nucleus pulposus of the disc. However, these IL-1 effects are more pronounced in miR-146a KO discs compared to WT discs. For example, absence of miR-146a increases the percentage of MMP-13 and ADAMTS-5 positive cells after treatment with IL-1. Thus, miR-146a appears to protect against IL-1 induced IVD degeneration and inflammation. Stimulation of endogenous miR-146a expression or exogenous delivery of miRNA-146a are viable therapeutic strategies that may decelerate disc degeneration and regain a normal homeostatic balance in extracellular matrix production and turn-over.

Effect of interleukin-8 on migration and invasion of CD133 + positive liver cancer stem cells

Objective To study the effect and possible mechanism of interleukin (IL)-8 on migration and invasion of CD133 + liver cancer stem cells (LCSCs).Methods CD133 + cells were isolated by using magnetic-activated cell sorting (MACS) from MHCC97-H cells.Migration,invasion and colony formation efficiency of CD133 +/CD133-cells were detected.IL-8 in the supernatants was detected by enzyme linked immunosorbent assay (ELISA).Tumor-forming ability was observed by xenografts in the BALB/c nude mice.The effect of IL-8 neutalizing antibody on migration,invasion and colony formation efficiency of the sorted cells was determined.Results IL-8 was up-regulated in CD133 + cells [(85.76 ± 2.55) ng/L] as compared with CD133-cells [(13.40 ± 2.19) ng/L].The CD133 + cells exhibited a greater ability of colony formation efficiency [(13.50 ± 0.62) ％ vs.(4.43 ± 0.31) ％],migration [(39.3 ± 3.2) vs.(18.0 ± 2.6)],invasion [(37.5 ± 3.0) vs.(20.3 ± 1.8)] and tumors initiation.Colony formation efficiency was decreased in both CD133 + [(4.63 ± 0.47)％ vs.(12.93 ± 0.55)％] and CD133-[(3.53 ±0.49)％ vs.(6.67 ±0.15)％] cells treated by IL-8 neutralizing antibody.IL-8 neutralizing antibody suppressed the migration [(24.7 ± 2.8) vs.(37.7 ± 2.8)] and invasion [(25.2 ± 2.1) vs.(40.2 ± 3.6)] of the CD133 + cells specifically.Conclusion CD133 plays a functional part in regulating migration and invasion of LCSCs via regulating IL-8 signaling. Key words: Interleukin-8 ; CD133 ; Liver cancer stem cells ; Invasion; Migration

Effects of interleukin-6 and tocilizumab on statin-induced apoptosis in melanoma cells.

e22212 Background: Statins induce apoptosis in tumour cells in vitro. Melanoma cells are especially susceptible to statin induced cell death. IL-6 can impair the growth of early stage melanoma, whe...

Immune Intervention for Type 1 Diabetes, 2012–2013

Immune Intervention for Type 1 Diabetes, 2012–2013

Effects of interleukin-6 and interleukin-1β on expression of growth differentiation factor-5 and Wnt signaling pathway genes in equine chondrocytes

To determine the effects of interleukin (IL)-6 and IL-1β stimulation on expression of growth differentiation factor (GDF)-5 and Wnt signaling pathway genes in equine chondrocytes. Macroscopically normal articular cartilage samples from 6 horses and osteochondral fragments (OCFs) from 3 horses. Chondrocyte pellets were prepared and cultured without stimulation or following stimulation with IL-6 or IL-1β for 1, 2, 12, and 48 hours; expression of GDF-5 was determined with a quantitative real-time PCR assay. Expression of genes in various signaling pathways was determined with microarrays for pellets stimulated for 1 and 2 hours. Immunohistochemical analysis was used to detect GDF-5, glycogen synthase kinase 3β (GSK-3β), and β-catenin proteins in macroscopically normal cartilage samples and OCFs. Chondrocytes stimulated with IL-6 had significantly higher GDF-5 expression within 2 hours versus unstimulated chondrocytes. Microarray analysis of Wnt signaling pathway genes indicated expression of GSK-3β and coiled-coil domain containing 88C increased after 1 hour and expression of β-catenin decreased after 2 hours of IL-6 stimulation. Results of immunohistochemical detection of proteins were similar to microarray analysis results. Chondrocytes in macroscopically normal articular cartilage and OCFs had immunostaining for GDF-5. Results indicated IL-6 stimulation decreased chondrocyte expression of the canonical Wnt signaling pathway transactivator β-catenin, induced expression of inhibitors of the Wnt pathway, and increased expression of GDF-5. This suggested IL-6 may inhibit the Wnt signaling pathway with subsequent upregulation of GDF-5 expression. Anabolic extracellular matrix metabolism in OCFs may be attributable to GDF-5 expression. This information could be useful for development of cartilage repair methods.

In vitro investigation of the roles of the proinflammatory cytokines tumor necrosis factor-α and interleukin-1 in murine osteoclastogenesis.

Whereas the monocyte/macrophage-colony stimulating factor (M-CSF) and the receptor activator of NF-кB ligand (RANKL) are essential and sufficient for osteoclastogenesis, a number of other cytokines including two proinflammatory cytokines, tumor necrosis factor-α (TNF-α), and interleukin-1 (IL-1), can exert profound effects on the osteoclastogenic process. However, the precise mode of action of TNF-α and IL-1 in osteoclastogenesis remains controversial. While some groups demonstrated that these two cytokines can promote murine osteoclastogenesis in vitro in the presence of M-CSF only, we and others showed that TNF-α-/IL-1-mediated osteoclastogenesis requires permissive levels of RANKL. This chapter describes the method that we have used to investigate the effects of TNF-α and IL-1 on osteoclast formation in in vitro osteoclastogenesis assays using primary murine bone marrow macrophages (BMMs). Detailed experimental conditions are provided and critical points are discussed to help the reader use the method to independently evaluate the roles of TNF-α and IL-1 in osteoclastogenesis in vitro. Moreover, this method can be used to further elucidate the signaling mechanisms by which these two cytokines act in concert with RANKL or with each other to modulate osteoclastogenesis.

Src contributes to IL6-induced vascular endothelial growth factor-C expression in lymphatic endothelial cells

Formation of lymphatic capillaries by lymphatic endothelial cells (LECs) occurs both in normal tissues as well as in pathological processes including tumor metastasis. Interleukin-6 (IL-6), a potent pro-inflammatory cytokine, has been shown to be highly elevated in various cancers. IL-6 has also been shown to increase tumor lymphangiogenesis through vascular endothelial growth factor-C (VEGF-C) induction in tumor cells. Although lymphangiogenesis is associated with lymph node metastasis and also resistance to conventional therapy in various cancers, the precise mechanisms of lymphangiogenesis in LECs remain unclear. This study aimed to investigate the signaling cascade involved in IL-6-induced VEGF-C expression in murine LECs (SV-LEC). The VEGF-C mRNA and protein levels were increased in SV-LECs exposed to IL-6. IL-6 time-dependently induced Src phosphorylation and downstream phosphorylation of ERK1/2 and p38MAPK. In contrast, PP2, an inhibitor of Src signaling, abrogated IL-6's effects on ERK1/2 and p38MAPK phosphorylation. IL-6 exposure also led to increase in VEGF-C promoter-luciferase activity as well as C/EBPβ- and κB-luciferase activities. VEGF-C promoter-, C/EBPβ- and κB-luciferase activities were all suppressed by Src, ERK1/2 or p38MAPK signaling blockades despite presence of IL-6. Finally, C/EBPβ and p65 binding to the VEGF-C promoter region were increased after IL-6 exposure in SV-LECs. Taken together, we report a Src-mediated ERK1/2 and p38MAPK activation resulting in C/EBPβ and p65 binding to the promoter region of VEGF-C, leading to VEGF-C expression in IL-6-exposed SV-LECs.

Extracellular Signal-Regulated Kinase Inhibition Modulates Rat Annulus Fibrosus Cell Response to Interleukin-1

Rat annulus fibrosus (AF) cells were activated with interleukin-1 (IL-1) with or without extracellular signal-regulated kinase (ERK) inhibition. Factors associated with the anabolic/catabolic balance of the disc were determined. To clarify the role of ERK pathway in AF cells response to IL-1. IL-1 plays an important role in intervertebral disc degeneration. ERK is an important inflammatory pathway that plays a crucial role in the expression of inflammatory and catabolic genes induced by IL-1 in chondrocytes. However, the role of the ERK pathway in AF cells response to IL-1 has not been fully investigated. Rat AF cells in monolayer culture were exposed to IL-1, with or without ERK inhibition; ribonucleic acid was isolated for real time polymerase chain reaction analysis of gene expression, conditioned media analyzed for nitrite, prostaglandin E-2, and IL-6, Western blot was performed to detect the changes of protein expression. ERK specific inhibitor U0126 significantly inhibited IL-1-induced ERK activation. IL-1-dependent upregulation of iNOS, IL-6, Cox-2, (MMP)-3, and MMP-13 was significantly reduced by ERK inhibition. The decreased gene expression of collagen I, collagen II, collagen IX, and IGF-1 induced by IL-1 was also reversed by U0126. Gene expression of ADAMTS-4, ADAMTS-5, and TGF-b were not affected by IL-1 or ERK inhibition. IL-1 moderately upregulated aggrecan and TIMP-1 expression, ERK inhibition had no significant effect on aggrecan expression but decreased TIMP-1 expression in the presence of IL-1. ERK inhibition reversed the changes of protein expression of MMP-3, MMP-13, TIMP-1, aggrecan and collagen II induced by IL-1. IL-1-induced nitric oxide, prostaglandin E-2, and IL-6 accumulation were also reduced by ERK inhibition. These results suggest that IL-1 induces an imbalance between anabolic and catabolic events in AF cells, ERK inhibition could provide some protection against the adverse effects of IL-1. N/A.

Effects of Interleukin-6 on the Expression of Tight Junction Proteins in Isolated Cerebral Microvessels from Yearling and Adult Sheep

Objectives: The blood-brain barrier is a selective diffusion barrier between brain parenchyma and the intravascular compartment. Tight junctions are integral components of the blood-brain barrier. Pro-inflammatory cytokines are important in the pathogenesis of brain injury and could modify the protein constituents of tight junctions. We hypothesized that interleukin-6 (IL-6) downregulates key protein constituents of endothelial tight junctions (e.g. occludin and claudin-5). Methods: We examined the effects of IL-6 on tight junction protein expression using an in vitro blood-brain barrier model. We isolated microvessels from yearling and adult ovine cerebral cortex and placed them into culture with IL-6 concentrations of 0 (control, phosphate-buffered saline), 1, 10, and 100 ng/ml for 24 h. Cerebral microvessels were harvested, Western immunoblot performed for occludin and claudin-5, densitometry performed, and results expressed as a ratio to control values. Results: Western immunoblot analysis showed that treatment with 100 ng/ml of IL-6, but not the lower concentrations, reduced (p < 0.05) occludin expression in microvessels from yearling and adult sheep and claudin-5 in microvessels from adult sheep. However, treatment with 10 ng/ml of IL-6 increased claudin-5 in microvessels from yearling sheep. The percent of lactate dehydrogenase released from the microvessels into the surrounding media was not increased by IL-6 treatment, suggesting that the reductions in tight junction proteins did not result from cell death. Treatment of adult cerebral cortical microvessels with IL-6 preincubated with anti-IL-6 monoclonal antibodies partially attenuated the reduction in claudin-5. Conclusion: We conclude that IL-6 modulates tight junction protein expression in cerebral cortical microvessels from yearling and adult sheep.

Effect of interleukin-6 and insulin resistance on early virological response of Egyptian chronic hepatitis C patients to combined pegylated interferon plus ribavirin therapy

Effect of interleukin-6 and insulin resistance on early virological response of Egyptian chronic hepatitis C patients to combined pegylated interferon plus ribavirin therapy

Multipotent stromal cells skew monocytes towards an anti-inflammatory interleukin-10-producing phenotype by production of interleukin-6

Multipotent stromal cells have immunomodulatory capacities and have been used in transplantation and autoimmune diseases. One of the effects of multipotent stromal cells involves the inhibition of dendritic cell differentiation. Since interleukin-6 and interleukin-10 are known to play a role in inhibiting immature dendritic cell differentiation, we hypothesized that these cytokines may also mediate the inhibitory effect of human multipotent stromal cells in immature dendritic cell differentiation. In order to test this hypothesis monocytes were cultured with interleukin-4 and granulocyte-monocyte colony-stimulating factor in the presence or absence of culture-expanded bone marrow-derived multipotent stromal cells. Neutralization and cytokine-depletion strategies were applied to reveal the cellular source and effect of interleukin-6 and interleukin-10. Addition of multipotent stromal cells to monocyte cultures significantly reduced the generation of immature dendritic cells (CD14(-)CD1a(+)) and resulted in the generation of CD14(+)CD1a(-) cells that displayed a significantly reduced immunostimulatory effect. We found that culture supernatants of co-cultures of multipotent stromal cells and monocytes contained higher concentrations of interleukin-6 and interleukin-10. Multipotent stromal cells produced interleukin-6 and neutralizing this interleukin-6 reversed the inhibitory effect of the multipotent cells. Interleukin-10 was not produced by multipotent stromal cells, but exclusively by monocytes after exposure to multipotent stromal cell-produced interleukin-6. In conclusion, through constitutive production of interleukin-6, multipotent stromal cells prevent the differentiation of monocytes towards antigen-presenting immunogenic cells and skew differentiation towards an anti-inflammatory interleukin-10-producing cell type.

EFFECTS OF PROINFLAMMATORY CYTOKINES ON MATRICELLULAR PROTEIN EXPRESSION IN HUMAN CARDIAC FIBROBLASTS

RationaleCardiac fibroblasts (CF) are integrally involved in the myocardial remodelling process and are highly responsive to proinflammatory cytokines such as interleukin-1 (IL-1) and tumour necrosis factor α (TNFα), whose levels...