Inhibition of T cell apoptosis in the aqueous humor of patients with uveitis by IL-6/soluble IL-6 receptor trans-signaling

Interleukin-6 trans-signaling induced laminin switch contributes to reduced trans-endothelial migration of granulocytic cells

BACKGROUND AND AIMS

Laminins are essential components of the endothelial basement membrane, which predominantly contains LN421 and LN521 isoforms. Regulation of laminin expression under pathophysiological conditions is largely unknown. In this study, we aimed to investigate the role of IL-6 in regulating endothelial laminin profile and characterize the impact of altered laminin composition on the phenotype, inflammatory response, and function of endothelial cells (ECs).

METHODS

HUVECs and HAECs were used for in vitro experiments. Trans-well migration experiments were performed using leukocytes isolated from peripheral blood of healthy donors. The BiKE cohort was used to assess expression of laminins in atherosclerotic plaques and healthy vessels. Gene and protein expression was analyzed using Microarray/qPCR and proximity extension assay, ELISA, immunostaining or immunoblotting techniques, respectively.

RESULTS

Stimulation of ECs with IL-6+sIL-6R, but not IL-6 alone, reduces expression of laminin α4 (LAMA4) and increases laminin α5 (LAMA5) expression at the mRNA and protein levels. In addition, IL-6+sIL-6R stimulation of ECs differentially regulates the release of several proteins including CXCL8 and CXCL10, which collectively were predicted to inhibit granulocyte transmigration. Experimentally, we demonstrated that granulocyte migration is inhibited across ECs pre-treated with IL-6+sIL-6R. In addition, granulocyte migration across ECs cultured on LN521 was significantly lower compared to LN421. In human atherosclerotic plaques, expression of endothelial LAMA4 and LAMA5 is significantly lower compared to control vessels. Moreover, LAMA5-to-LAMA4 expression ratio was negatively correlated with granulocytic cell markers (CD177 and myeloperoxidase (MPO)) and positively correlated with T-lymphocyte marker CD3.

CONCLUSIONS

We showed that expression of endothelial laminin alpha chains is regulated by IL-6 trans-signaling and contributes to inhibition of trans-endothelial migration of granulocytic cells. Further, expression of laminin alpha chains is altered in human atherosclerotic plaques and is related to intra-plaque abundance of leukocyte subpopulations.

Macrophages Phenotype Regulated by IL-6 Are Associated with the Prognosis of Platinum-Resistant Serous Ovarian Cancer: Integrated Analysis of Clinical Trial and Omics

Background

The treatment of platinum-resistant recurrent ovarian cancer (PROC) is a clinical challenge and a hot topic. Tumor microenvironment (TME) as a key factor promoting ovarian cancer progression. Macrophage is a component of TME, and it has been reported that macrophage phenotype is related to the development of PROC. However, the mechanism underlying macrophage polarization and whether macrophage phenotype can be used as a prognostic indicator of PROC remains unclear.

Methods

We used ESTIMATE to calculate the number of immune and stromal components in high-grade serous ovarian cancer (HGSOC) cases from The Cancer Genome Atlas database. The differential expression genes (DEGs) were analyzed via protein-protein interaction network, Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene ontology (GO) analysis to reveal major pathways of DEGs. CD80 was selected for survival analysis. IL-6 was selected for gene set enrichment analysis (GSEA). A subsequent cohort study was performed to confirm the correlation of IL-6 expression with macrophage phenotype in peripheral blood and to explore the clinical utility of macrophage phenotype for the prognosis of PROC patients.

Results

A total of 993 intersecting genes were identified as candidates for further survival analysis. Further analysis revealed that CD80 expression was positively correlated with the survival of HGSOC patients. The results of GO and KEGG analysis suggested that macrophage polarization could be regulated via chemokine pathway and cytokine-cytokine receptor interaction. GSEA showed that the genes were mainly enriched in IL-6-STAT-3. Correlation analysis for the proportion of tumor infiltration macrophages revealed that M2 was correlated with IL-6. The results of a cohort study demonstrated that the regulation of macrophage phenotype by IL-6 is bidirectional. The high M1% was a protective factor for progression-free survival.

Conclusion

Thus, the macrophage phenotype is a prognostic indicator in PROC patients, possibly via a hyperactive IL-6-related pathway, providing an additional clue for the therapeutic intervention of PROC.

Senescence of Tumor Cells in Anticancer Therapy—Beneficial and Detrimental Effects

Cellular senescence process results in stable cell cycle arrest, which prevents cell proliferation. It can be induced by a variety of stimuli including metabolic stress, DNA damage, telomeres shortening, and oncogenes activation. Senescence is generally considered as a process of tumor suppression, both by preventing cancer cells proliferation and inhibiting cancer progression. It can also be a key effector mechanism for many types of anticancer therapies such as chemotherapy and radiotherapy, both directly and through bioactive molecules released by senescent cells that can stimulate an immune response. Senescence is characterized by a senescence-associated secretory phenotype (SASP) that can have both beneficial and detrimental impact on cancer progression. Despite the negatives, attempts are still being made to use senescence to fight cancer, especially when it comes to senolytics. There is a possibility that a combination of prosenescence therapy—which targets tumor cells and causes their senescence—with senotherapy—which targets senescent cells, can be promising in cancer treatment. This review provides information on cellular senescence, its connection with carcinogenesis and therapeutic possibilities linked to this process.

Systems Immunology Analyses of STAT1 Gain-of-Function Immune Phenotypes Reveal Heterogeneous Response to IL-6 and Broad Immunometabolic Roles for STAT1

Patients with STAT1 gain-of-function (GOF) pathogenic variants have enhanced or prolonged STAT1 phosphorylation following cytokine stimulation and exhibit increased yet heterogeneous susceptibility to infections, autoimmunity, and cancer. Although disease phenotypes are diverse and other genetic factors contribute, how STAT1 GOF affects cytokine sensitivity and cell biology remains poorly defined. In this study, we analyzed the immune and immunometabolic profiles of two patients with known pathogenic heterozygous STAT1 GOF mutation variants. A systems immunology approach of peripheral blood cells from these patients revealed major changes in multiple immune cell compartments relative to healthy adult and pediatric donors. Although many phenotypes of STAT1 GOF donors were shared, including increased Th1 cells but decreased class-switched B cells and plasmacytoid dendritic cell populations, others were heterogeneous. Mechanistically, hypersensitivity for cytokine-induced STAT1 phosphorylation in memory T cell populations was particularly evident in response to IL-6 in one STAT1 GOF patient. Immune cell metabolism directly influences cell function, and the STAT1 GOF patients shared an immunometabolic phenotype of heightened glucose transporter 1 (GLUT1) and carnitine palmitoyl transferase 1A (CPT1a) expression across multiple immune cell lineages. Interestingly, the metabolic phenotypes of the pediatric STAT1 GOF donors more closely resembled or exceeded those of healthy adult than healthy age-similar pediatric donors, which had low expression of these metabolic markers. These results define new features of STAT1 GOF patients, including a differential hypersensitivity for IL-6 and a shared increase in markers of metabolism in many immune cell types that suggests a role for STAT1 in metabolic regulation of immunity.

Genetic variants affecting chemical mediated skin immunotoxicity

The skin is an immune-competent organ and this function may be impaired by exposure to chemicals, which may ultimately result in immune-mediated dermal disorders. Interindividual variability to chemical-induced skin immune reactions is associated with intrinsic individual characteristics and their genomes. In the last 30-40 years, several genes influencing susceptibility to skin immune reactions were identified. The aim of this review is to provide information regarding common genetic variations affecting skin immunotoxicity. The polymorphisms selected for this review are related to xenobiotic-metabolizing enzymes (CYPA1 and CYPB1 genes), antioxidant defense (GSTM1, GSTT1, and GSTP1 genes), aryl hydrocarbon receptor signaling pathway (AHR and ARNT genes), skin barrier function transepidermal water loss (FLG, CASP14, and SPINK5 genes), inflammation (TNF, IL10, IL6, IL18, IL31, and TSLP genes), major histocompatibility complex (MHC) and neuroendocrine system peptides (CALCA, TRPV1, ACE genes). These genes present variants associated with skin immune responses and diseases, as well as variants associated with protecting skin immune homeostasis following chemical exposure. The molecular and association studies focusing on these genetic variants may elucidate their functional consequences and contribution in the susceptibility to skin immunotoxicity. Providing information on how genetic variations affect the skin immune system may reduce uncertainties in estimating chemical hazards/risks for human health in the future.

TCR-T Immunotherapy: The Challenges and Solutions

T cell receptor-engineered T cell (TCR-T) therapy is free from the limit of surface antigen expression of the target cells, which is a potential cellular immunotherapy for cancer treatment. Significant advances in the treatment of hematologic malignancies with cellular immunotherapy have aroused the interest of researchers in the treatment of solid tumors. Nevertheless, the overall efficacy of TCR-T cell immunotherapy in solid tumors was not significantly high when compared with hematological malignancies. In this article, we pay attention to the barriers of TCR-T cell immunotherapy for solid tumors, as well as the strategies affecting the efficacy of TCR-T cell immunotherapy. To provide some reference for researchers to better overcome the impact of TCR-T cell efficiency in solid tumors.

Research Progress on the Mechanism of Natural Product Ingredients in the Treatment of Uveitis

Background

As the spectrum of ophthalmic diseases keeps changing, uveitis has gradually become one of the major blinding eye diseases in the world. In recent years, it has become a research hotspot to select effective components for uveitis treatment from natural drugs.

Methods

We searched PubMed and EMBASE databases for studies written in English as well as Chinese National Knowledge Infrastructure (CNKI), CQVIP, and Wan Fang database for studies written in Chinese (inception through 30 December 2020).

Results

Eight kinds of natural product ingredients were included in this article. They were found to not only regulate the expression of cytokines, proliferation, and differentiation of T help cells but also inhibit the damage of cytokines and inflammatory cells to uvea, blood aqueous barrier, and blood retinal barrier.

Conclusion

Natural product ingredients have their unique advantages in the treatment of uveitis. They have good anti-inflammatory effects without causing serious adverse reactions, which enables them to be promising choices for preventive and therapeutic strategy of uveitis.

The calcium-binding protein S100B reduces IL6 production in malignant melanoma via inhibition of RSK cellular signaling

S100B is frequently elevated in malignant melanoma. A regulatory mechanism was uncovered here in which elevated S100B lowers mRNA and secreted protein levels of interleukin-6 (IL6) and inhibits an autocrine loop whereby IL6 activates STAT3 signaling. Our results showed that S100B affects IL6 expression transcriptionally. S100B was shown to form a calcium-dependent protein complex with the p90 ribosomal S6 kinase (RSK), which in turn sequesters RSK into the cytoplasm. Consistently, S100B inhibition was found to restore phosphorylation of a nuclear located RSK substrate, CREB, which is a potent transcription factor for IL6 expression. Thus, elevated S100B reduces IL6-STAT3 signaling via RSK signaling pathway in malignant melanoma. Indeed, the elevated S100B levels in malignant melanoma cell lines correspond to low levels of IL6 and p-STAT3.

Gene-Edited Interleukin CAR-T Cells Therapy in the Treatment of Malignancies: Present and Future

In recent years, chimeric antigen receptor T cells (CAR-T cells) have been faced with the problems of weak proliferation and poor persistence in the treatment of some malignancies. Researchers have been trying to perfect the function of CAR-T by genetically modifying its structure. In addition to the participation of T cell receptor (TCR) and costimulatory signals, immune cytokines also exert a decisive role in the activation and proliferation of T cells. Therefore, genetic engineering strategies were used to generate cytokines to enhance tumor killing function of CAR-T cells. When CAR-T cells are in contact with target tumor tissue, the proliferation ability and persistence of T cells can be improved by structurally or inductively releasing immunoregulatory molecules to the tumor region. There are a large number of CAR-T cells studies on gene-edited cytokines, and the most common cytokines involved are interleukins (IL-7, IL-12, IL-15, IL-18, IL-21, IL-23). Methods for the construction of gene-edited interleukin CAR-T cells include co-expression of single interleukin, two interleukin, interleukin combined with other cytokines, interleukin receptors, interleukin subunits, and fusion inverted cytokine receptors (ICR). Preclinical and clinical trials have yielded positive results, and many more are under way. By reading a large number of literatures, we summarized the functional characteristics of some members of the interleukin family related to tumor immunotherapy, and described the research status of gene-edited interleukin CAR-T cells in the treatment of malignant tumors. The objective is to explore the optimized strategy of gene edited interleukin-CAR-T cell function.

Targeting interleukin-6 to treat neuromyelitis optica spectrum disorders: Implications from immunology, the FcRn pathway and clinical experience

Neuromyelitis optica spectrum disorder (NMOSD) is a rare disease of the central nervous system (CNS) that is associated with poor outcomes for patients. Until recently, when complement inhibitors were approved, there was no approved therapy. Most recently, clinical trials of interleukin-6 (IL-6) blockade showed a therapeutic benefit for NMOSD. In this review, we introduce the immunological basis of IL-6 blockade in NMOSD and summarize current knowledge about the clinical use of the IL-6 receptor inhibitors tocilizumab and satralizumab. The aim of extending the half-life of monoclonal antibodies (mAbs) has been actualized by successful clinical translation for Satralizumab, achieved via the neonatal Fc receptor (FcRn) pathway. The basic principles of FcRn are highlighted in this review together with the potential therapeutic benefits of this emerging technology.

Deletion of IKK2 in haematopoietic cells of adult mice leads to elevated interleukin-6, neutrophilia and fatal gastrointestinal inflammation

The IκB kinase complex, consisting of IKK1, IKK2 and the regulatory subunit NEMO, is required for NF-κB signalling following the activation of several cell surface receptors, such as members of the Tumour Necrosis Factor Receptor superfamily and the Interleukin-1 Receptor. This is critical for haematopoietic cell proliferation, differentiation, survival and immune responses. To determine the role of IKK in the regulation of haematopoiesis, we used the Rosa26^Cre-ERT2 Cre/lox recombination system to achieve targeted, haematopoietic cell-restricted deletion of the genes for IKK1 or IKK2 in vivo. We found that the IKK complex plays a critical role in haematopoietic cell development and function. Deletion of IKK2, but not loss of IKK1, in haematopoietic cells led to an expansion of CD11b/Gr-1-positive myeloid cells (neutrophilia), severe anaemia and thrombocytosis, with reduced numbers of long-term haematopoietic stem cells (LT-HSCs), short-term haematopoietic stem cells (ST-HSCs) and multipotential progenitor cells (MPPs), increased circulating interleukin-6 (IL-6) and severe gastrointestinal inflammation. These findings identify distinct functions for the two IKK catalytic subunits, IKK1 and IKK2, in the haematopoietic system.

IL-6 as a major regulator of MDSC activity and possible target for cancer immunotherapy

Myeloid-derived suppressor cells (MDSC) are generated during tumor progression and suppress the anti-tumor functions of T and natural killer (NK) cells. Their enrichment is associated with a bad prognosis and a worse outcome of immunotherapy in cancer patients. The cytokine interleukin (IL)-6 was found to be a crucial regulator of MDSC accumulation and activation as well as a factor, stimulating tumor cell proliferation, survival, invasiveness and metastasis. Accordingly, IL-6 can serve as a negative prognostic marker in cancer. On the other hand, this cytokine is also involved in T cell activation. This review discusses the pleiotropic effects of IL-6 on immune cell populations that are critical for tumor development, such as MDSC and T cells, and summarizes the data on targeting IL-6 or IL-6 receptor (IL-6R) for tumor immunotherapy to block MDSC-mediated immunosuppression in cancer patients.

IL-6 regulates CCR5 expression and immunosuppressive capacity of MDSC in murine melanoma

Background

Myeloid-derived suppressor cells (MDSC) play a major role in the immunosuppressive melanoma microenvironment. They are generated under chronic inflammatory conditions characterized by the constant production of inflammatory cytokines, chemokines and growth factors, including IL-6. Recruitment of MDSC to the tumor is mediated by the interaction between chemokines and chemokine receptors, in particular C–C chemokine receptor (CCR)5. Here, we studied the mechanisms of CCR5 upregulation and increased immunosuppressive function of CCR5⁺ MDSC.

Methods

The immortalized myeloid suppressor cell line MSC-2, primary immature myeloid cells and in vitro differentiated MDSC were used to determine factors and molecular mechanisms regulating CCR5 expression and immunosuppressive markers at the mRNA and protein levels. The relevance of the identified pathways was validated on the RET transgenic mouse melanoma model, which was also used to target the identified pathways in vivo.

Results

IL-6 upregulated the expression of CCR5 and arginase 1 in MDSC by a STAT3-dependent mechanism. MDSC differentiated in the presence of IL-6 strongly inhibited CD8⁺ T cell functions compared with MDSC differentiated without IL-6. A correlation between IL-6 levels, phosphorylated STAT3 and CCR5 expression in tumor-infiltrating MDSC was demonstrated in the RET transgenic melanoma mouse model. Surprisingly, IL-6 overexpressing tumors grew significantly slower in mice accompanied by CD8⁺ T cell activation. Moreover, transgenic melanoma-bearing mice treated with IL-6 blocking antibodies showed significantly accelerated tumor development.

Conclusion

Our in vitro and ex vivo findings demonstrated that IL-6 induced CCR5 expression and a strong immunosuppressive activity of MDSC, highlighting this cytokine as a promising target for melanoma immunotherapy. However, IL-6 blocking therapy did not prove to be effective in RET transgenic melanoma-bearing mice but rather aggravated tumor progression. Further studies are needed to identify particular combination therapies, cancer entities or patient subsets to benefit from the anti-IL-6 treatment.

Effects of pentasa-combined probiotics on the microflora structure and prognosis of patients with inflammatory bowel disease

BACKGROUND/AIMS

The aim of the present study was to investigate the effects of the combination treatment of pentasa and probiotics on the microflora composition and prognosis in patients with inflammatory bowel disease (IBD).

MATERIALS AND METHODS

A total of 40 patients with IBD (19 control group and 21 observation group) were randomized. Patients in the control group were given pentasa, and patients in the observation group were given probiotics along with pentasa. The microflora composition, biochemical indices, inflammatory markers, and activity scores of the two groups were analyzed.

RESULTS

After treatment, the number of enterobacteria, enterococci, saccharomyces, and bacteroides; the levels of fecal lactoferrin, 1-antitrypsin, β2-microglobulin, high-sensitivity C-reactive protein, and interleukin (IL)-6; activity scores; and recurrence rate in the observation group were significantly lower than those in the control group. Bifidobacterium and lactobacillus counts and IL-4 levels were significantly higher in the observation group than in the control group.

CONCLUSION

The combination of probiotics and pentasa can improve microflora composition in patients with IBD and reduce the level of inflammatory cytokines; therefore, it is worthy of further clinical validation.

Characteristic Cytokine Profiles of Aqueous Humor in Glaucoma Secondary to Sturge-Weber Syndrome

Patients with Sturge-Weber syndrome (SWS) are susceptible to ocular complications, and among them, glaucoma is one of the most frequent forms. In current study, we utilized multiplex human cytokine antibody array to simultaneously measure the concentration of 40 cytokines in aqueous humor (AH) of patients with SWS-induced glaucoma (SG), or from patients with senile cataract as controls. Compared with the control group, levels of interleukin (IL)-12p40, macrophage inflammatory protein (MIP)-1d, tumor necrosis factor-alpha (TNF-a), IL-5, IL-7, interleukin-6 receptor (IL-6R), and B lymphocyte chemoattractant (BLC) in AH were significantly higher in SG group. Samples from SG patients displayed significantly lower levels of MIP-1b, IL-6, MIP-1a, and monocyte chemoattractant protein (MCP)-1 than controls. Further analysis showed that IL-7, MIP-1a, TNF-a were positively correlated with intraocular pressure (IOP) in patients with early-onset SG. Moreover, IL-12p40 was negatively correlated with age in patients with SG. These cytokines may make contributions to the immunopathogenesis or progression of glaucoma in patients with SWS.

Modelling Macular Edema: The Effect of IL-6 and IL-6R Blockade on Human Blood-Retinal Barrier Integrity In Vitro

Purpose

Macular edema (ME) is a leading cause of visual loss in a range of retinal diseases and despite the use of antivascular endothelial growth factor (anti-VEGF) agents, its successful treatment remains a major clinical challenge. Based on the indirect clinical evidence that interleukin-6 (IL-6) is a key additional candidate mediator of ME, we interrogated the effect of IL-6 on blood–retinal barrier (BRB) integrity in vitro.

Methods

Human retinal pigment epithelial cell (ARPE-19) and human retinal microvascular endothelial cell (HRMEC) monolayers were used to mimic the outer and inner BRB, respectively. Their paracellular permeability was assessed by measuring the passive permeation of 40 kDa fluorescein isothiocyanate (FITC)-dextran across confluent cells in the presence of IL-6. Transendothelial/epithelial electrical resistance (TEER) then was measured and the distribution of the tight junction protein ZO-1 was assessed by immunofluorescence using confocal microscopy.

Results

Treatment with IL-6 for 48 hours significantly increased the diffusion rate of FITC-dextran, decreased TEER, and disrupted the distribution of ZO-1 in ARPE-19 cells, which constitutively express the IL-6 transmembrane receptor, and this was reversed with IL-6R blockade. In contrast, IL-6 did not affect the paracellular permeability, TEER, or ZO-1 distribution in HRMECs.

Conclusions

These in vitro data support the hypothesis that IL-6 reversibly disrupts the integrity of ARPE-19 cells, but it does not affect HRMECs.

Translational Relevance

IL-6 is a candidate therapeutic target in the treatment of outer BRB driven ME.

Outcomes of treatment with sirolimus for non-infectious uveitis: a meta-analysis and systematic review

Background

Uveitis is a group of intraocular inflammatory diseases whose primary treatment involves immunosuppression. Although corticosteroids (CSs) remain the mainstay therapy, sirolimus is among the recently studied immunomodulatory drugs for treating noninfectious uveitis (NIU).

Objective

The aim of this review was to assess and summarize the updated evidence on the outcomes of treatment with sirolimus for NIU.

Materials and methods

Two reviewers conducted a systematic search on November 5, 2018, of electronic databases (EMBASE, MEDLINE, and The Cochrane Library) and clinical trial registers having no restrictions on language or publication date. The primary outcome was uveitis activity as measured by vitreous haze (VH), while the secondary outcomes included central macular thickness (CMT), best-corrected visual acuity (BCVA), CS-sparing effect, IOP elevation, and other adverse events. A meta-analysis was conducted on selected studies with appropriate clinical and methodological homogeneity.

Results

Seven studies were included and reviewed. Four randomized clinical trials were eligible for meta-analysis: SAVE 2013, One-year outcomes of the SAVE study, SAVE 2 2016, SAKURA 2016. The pooled proportions of inflammation control (VH improvement) were 38% (95% CI 16.19%-62.66%) during a 6-month follow-up and 49.97% (95% CI 16.19%-83.03%) during a 6- to 12-month follow-up with the latter showing a significantly higher response rate (p=0.0472). BCVA improvement was 62.2% (95% CI 33.17%-87.11%) during a 6-month follow-up and 56.86% (95% CI 20.91%-89.05%) during a 6- to 12-month follow-up with no significant difference between the two (p=0.3705). Increased IOP remained at 7.11% (95% CI 3.46%-12.68%) for both a 6-month follow-up and up to a 12-month follow-up duration. The CS-sparing effect of sirolimus was also well demonstrated. A reduction in CMT was observed, and only minor drug-related adverse events were reported in all the studies reviewed.

Conclusion

This review provided evidence that sirolimus is a promising treatment option for controlling inflammatory activity, improving visual acuity, and sparing CS use with minor adverse events for NIU.

Activation of naïve CD4+ T cells re-tunes STAT1 signaling to deliver unique cytokine responses in memory CD4+ T cells

The cytokine IL-6 controls the survival, proliferation and effector characteristics of lymphocytes through activation of the transcription factors STAT1 and STAT3. While STAT3 activity is an ever-present feature of IL-6 signaling in CD4⁺ T cells, prior T-cell receptor activation limits the IL-6 control of STAT1 in effector and memory populations. Here we show that STAT1 phosphorylation in response to IL-6 was regulated by protein tyrosine phosphatases (PTPN2, PTPN22) expressed in response to the activation of naïve CD4⁺ T cells. Transcriptomic and chromatin immunoprecipitation-sequencing of IL-6 responses in naïve and effector memory CD4⁺ T cells showed how the suppression of STAT1 activation shaped the functional identity and effector characteristics of memory CD4⁺ T cells. Thus, protein tyrosine phosphatases induced by activation of naïve T cells determined the way activated or memory CD4⁺ T cells sensed and interpreted cytokine signals.

Intraocular cytokine profile and autoimmune reactions in retinitis pigmentosa, age-related macular degeneration, glaucoma and cataract

Purpose

To analyse intraocular cytokine levels and prevalence of intraocular antiretinal antibodies (ARAs) in patients with retinitis pigmentosa (RP), age‐related macular degeneration (AMD), glaucoma and cataract, and correlate the results to clinical manifestations.

Methods

We collected intraocular fluid samples from patients with RP (n = 25), AMD (n = 12), glaucoma (n = 28) and cataract (n = 22), and serum samples paired with the intraocular fluids from patients with RP (N = 7) and cataract (n = 10). Interleukin (IL)‐1β, IL‐1ra, IL‐2, IL‐6, IL‐6rα, IL‐7, IL‐8, IL‐10, IL‐17A, IL‐23, thymus‐ and activation‐regulated chemokine (TARC), monocyte chemoattractant protein‐1 (MCP‐1), tumour necrosis factor‐alpha (TNF‐α), placental growth factor (PlGF) and vascular endothelial growth factor (VEGF) were measured using a multiplex assay. Antiretinal antibodies (ARA) detection was performed by indirect immunofluorescence.

Results

Increasing age was associated with increasing levels of IL‐6, IL‐8, TNF‐α and VEGF. All patient groups exhibited distinct profiles of intraocular cytokines. Intraocular levels of IL‐8 were highest in patients with AMD and glaucoma. Cataract patients exhibited high intraocular levels of IL‐23. Intraocular levels of IL‐2, IL‐6, MCP‐1 and PlGF in RP patients exceeded the levels of serum, indicating intraocular production. Intraocular ARAs were found in only one patient with AMD.

Conclusion

Increased levels of inflammatory cytokines in intraocular fluid of patients with originally noninflammatory ocular diseases show that intraocular inflammation is involved in their pathogenesis of these entities. Moreover, we show that increasing age is associated with increasing levels of intraocular cytokines and conclude that future studies on intraocular mediators should be corrected for age of patients.

CD83+ CCR7+ NK cells induced by interleukin 18 by dendritic cells promote experimental autoimmune uveitis

Natural killer (NK) cells have been reported to play a pathological role in autoimmune uveitis. However, the mechanisms regarding NK cells in uveitis and factors that affect NK-cell activation in this condition remain unclear. Here, we report that the number of CD3- NK1.1+ CD83+ CCR7+ cells is increased in the inflamed eyes within a mouse model of experimental autoimmune uveitis (EAU), and these cells express elevated levels of NKG2D, CD69 and IFN-γ. Adoptively transferring CD83+ CCR7+ NK cells aggravates EAU symptoms and increases the number of CD4+ IFN-γ+ T cells and dendritic cells (DCs) within the eye. These CD83+ CCR7+ NK cells then promote the maturation of DCs and IFN-γ expression within T cells as demonstrated in vitro. Furthermore, IL-18, as primarily secreted by DCs in the eyes, is detected to induce CD83+ CCR7+ NK cells. In EAU mice, anti-IL-18R antibody treatment also decreases retinal tissue damage, as well as the number of infiltrating CD83+ CCR7+ NK cells, T cells and DCs in the inflamed eyes and spleens of EAU mice. These results suggest that CD83+ CCR7+ NK cells, as induced by IL-18 that primarily secreted by DCs, play a critical pathological role in EAU. Anti-IL-18R antibody might serve as a potential therapeutic agent for uveitis through its capacity to inhibit CD83+ CCR7+ NK cells infiltration.

Interleukin-6 Rescues Lymphocyte from Apoptosis and Exhaustion Induced by Chronic Hepatitis C Virus Infection

Chronic hepatitis C virus (HCV) infection appears to trigger the onset of immune exhaustion and apoptosis to potentially assist viral persistence inside the host, eventually leading to exacerbated conditions of inflammation and hepatocarcinogenesis. Growing evidence suggests that spontaneous apoptosis of peripheral blood mononuclear cells (PBMCs) could be one of the potential immune impairment mechanisms in chronic viral infection. Interleukin-6 (IL-6) is a pleiotropic cytokine that plays an essential role in regulating immune and inflammatory responses. Owing to its known role in priming T cell growth, differentiation, and inhibition of lymphocyte apoptosis, we investigated the protective effect of IL-6 in rescuing lymphocytes from apoptosis and functional exhaustion in chronic HCV infection. The expression pattern of antiapoptotic (Mcl-1 and Bcl-2), proapoptotic (caspase-3 and Bim) genes along with interferon gamma (IFN-γ) and T cell inhibitory receptor (TIM-3) was analyzed before and after in vitro IL-6 treatment of patient-derived PBMCs. It was observed that the expression of antiapoptotic genes, Mcl-1 and Bcl-2 increased (threefolds and twofolds, respectively) and there was a considerable downregulation in T cell inhibitory receptor (TIM-3) and caspase-3. Similarly, the capacity of PBMCs to produce IFN-γ was also significantly increased (p < 0.001) depicting the promising nature of IL-6 in enhancing lymphocyte effector function. Summing it up, the study supports the positive role of IL-6 in rescuing PBMC population; however, the cytokine alone is not sufficient to sustain the adaptive immunity. It could be used as a potential candidate for combinational therapy along with other regulatory factors for ex vivo enhancement of lymphocyte and may help in moving one step toward adoptive T cell therapy in chronic HCV infection.

Soluble CD83 Alleviates Experimental Autoimmune Uveitis by Inhibiting Filamentous Actin-Dependent Calcium Release in Dendritic Cells

Soluble CD83 (sCD83) is the extracellular domain of the membrane-bound CD83 molecule, and known for its immunoregulatory functions. Whether and how sCD83 participates in the pathogenesis of uveitis, a serious inflammatory disease of the eye that can cause visual disability and blindness, is unknown. By flow cytometry and imaging studies, we show that sCD83 alleviates experimental autoimmune uveitis (EAU) through a novel mechanism. During onset and recovery of EAU, the level of sCD83 rises in the serum and aqueous humor, and CD83⁺ leukocytes infiltrate the inflamed eye. Systemic or topical application of sCD83 exerts a protective effect by decreasing inflammatory cytokine expression, reducing ocular and splenic leukocyte including CD4⁺ T cells and dendritic cells (DCs). Mechanistically, sCD83 induces tolerogenic DCs by decreasing the synaptic expression of co-stimulatory molecules and hampering the calcium response in DCs. These changes are caused by a disruption of the cytoskeletal rearrangements at the DC–T cell contact zone, leading to altered localization of calcium microdomains and suppressed T-cell activation. Thus, the ability of sCD83 to modulate DC-mediated inflammation in the eye could be harnessed to develop new immunosuppressive therapeutics for autoimmune uveitis.

mTOR-inhibiting pharmacotherapy for the treatment of non-infectious uveitis: a systematic review protocol

BACKGROUND

Non-infectious uveitis represents a sub-type of intraocular inflammation often associated with disorders of immune dysregulation. If untreated, the intraocular inflammation may progress to severe visual impairment and blindness. Current treatment is heavily reliant on systemic corticosteroid, often at doses associated with severe side effects. There is a need for efficacious corticosteroid-sparing immunomodulatory therapy for these patients. Current immunomodulators include various immunosuppressants and biologics but mammalian target of rapamycin (mTOR) inhibitors (such as sirolimus and everolimus) may also be contenders for this role. The systematic review proposed here will evaluate the evidence for the use of sirolimus and everolimus in the context of non-infectious uveitis.

METHOD/DESIGN

Standard systematic review methodology will be used to identify, select and extract data from any comparative or non-comparative study of mTOR inhibitors in patients with non-infectious uveitis excluding case reports. Searches of bibliographic databases (MEDLINE, EMBASE, The Cochrane Library and CINAHL) and clinical trials registers will be performed, with no restriction on language or date of publication. Translation of non-English language articles will be undertaken where necessary. The primary outcome of interest will be uveitis activity as measured by vitreous haze. Secondary outcomes will include other pre-specified measures of uveitis activity (such as anterior chamber cells or central macular thickness) best corrected visual acuity, heath-related quality of life, requirement for concurrent treatment and adverse events. Risk of bias assessment will be performed appropriate to each study design. Study selection, data extraction and risk of bias assessment will be undertaken by two reviewers independently. Data will be grouped, tabulated and narratively synthesised. Meta-analysis will be undertaken where appropriate clinical and methodological homogeneity exists. The review will be published according to PRISMA guidance.

DISCUSSION

Studies of various designs have investigated the clinical use of mTOR inhibitors for non-infectious uveitis, and a large international randomised controlled trail of sirolimus for non-infectious uveitis is due to report. The findings of this systematic review will help inform ophthalmologists and aid the improvement of treatment protocols for non-infectious uveitis with regard to the use of mTOR inhibitors.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42017056390.

Interleukin-6-mediated trans-signaling inhibits transforming growth factor-β signaling in trabecular meshwork cells

Glaucoma is one of the major causes of blindness, and transforming growth factor-β2 (TGF-β2) has been found to be elevated in the aqueous humor of eyes with primary open-angle glaucoma (POAG). TGF-β2 in aqueous humor causes the glaucoma-related fibrosis of human trabecular meshwork (HTM), suggesting an important role of TGF-β in POAG pathogenesis. Here, we sought to elucidate the effects of IL-6 trans-signaling on TGF-β signaling in HTM cells. Using a multiplex immunoassay, POAG patients decreased IL-6 levels and increased soluble IL-6 receptor (sIL-6R) levels compared with the controls. In in vitro experiments, we observed that the IL-6 level was increased in the conditioned medium of HTM cells after TGF-β2 stimulation. To elucidate the relationship between TGF-β2 and IL-6 in HTM cells, we conducted Western blotting and immunohistochemical analyses, and we noted that the combination of IL-6 and sIL-6R (IL6/sIL-6R) suppressed TGF-β-induced up-regulation of α-smooth muscle actin in HTM cells, whereas IL-6 alone did not. This suggests that trans-signaling, not classic signaling, of IL-6 suppresses TGF-β-induced fibrosis of HTM. IL6/sIL-6R also suppressed TGF-β-mediated activation of myosin light chain 2 (MLC2), Smad2, and p38. Of note, these inhibitory effects of IL6/sIL-6R on TGF-β were partly reduced by siRNA-mediated knockdown of STAT3. Moreover, IL-6/sIL-6R partly inhibited TGF-β-induced activation of the Smad-sensitive promoter detected with luciferase reporter gene assays and up-regulation of TGFRI and TGFRII, evaluated by quantitative real-time RT-PCR. Strikingly, overexpression of TGFRI and TGFRII diminished these inhibitory effects of IL-6/sIL-6R. We conclude that of IL-6-mediated trans-signaling potently represses TGF-β signaling in HTM cells.

Interleukin-6: A promising cytokine to support liver regeneration and adaptive immunity in liver pathologies

Liver pathologies (fibrosis, cirrhosis, alcoholic, non-alcoholic diseases and hepatocellular carcinoma) represent one of the most common causes of death worldwide. A number of genetic and environmental factors contribute to the development of liver diseases. Interleukin-6 (IL-6) is a pleiotropic cytokine, exerting variety of effects on inflammation, liver regeneration, and defence against infections by regulating adaptive immunity. Due to its high abundance in inflammatory settings, IL-6 is often viewed as a detrimental cytokine. However, accumulating evidence supports the view that IL-6 has a beneficial impact in numerous liver pathologies, due to its roles in liver regeneration and in promoting an anti-inflammatory response in certain conditions. IL-6 promotes proliferation, angiogenesis and metabolism, and downregulates apoptosis and oxidative stress; together these functions are critical for mediating hepatoprotection. IL-6 is also an important regulator of adaptive immunity where it induces T cell differentiation and regulates autoimmunity. It can augment antiviral adaptive immune responses and mitigate exhaustion of T cells during chronic infection. This review focuses on studies that present IL-6 as a key factor in regulating liver regeneration and in supporting effector immune functions and suggests that these functions of IL-6 can be exploited in treatment strategies for liver pathologies.

The choice of cryopreservation method affects immune compatibility of human cardiovascular matrices

Conventional frozen cryopreservation (CFC) is currently the gold standard for cardiovascular allograft preservation. However, inflammation and structural deterioration limit transplant durability. Ice-free cryopreservation (IFC) already demonstrated matrix structure preservation combined with attenuated immune responses. In this study, we aim to explore the mechanisms of this diminished immunogenicity in vitro. First, we characterized factors released by human aortic tissue after CFC and IFC. Secondly, we analyzed co-cultures with human peripheral blood mononuclear cells, purified monocytes, T cells and monocyte-derived macrophages to examine functional immune effects triggered by the tissue or released cues. IFC tissue exhibited significantly lower metabolic activity and release of pro-inflammatory cytokines than CFC tissue, but surprisingly, more active transforming growth factor β. Due to reduced cytokine release by IFC tissue, less monocyte and T cell migration was detected in a chemotaxis system. Moreover, only cues from CFC tissue but not from IFC tissue amplified αCD3 triggered T cell proliferation. In a specifically designed macrophage-tissue assay, we could show that macrophages did not upregulate M1 polarization markers (CD80 or HLA-DR) on either tissue type. In conclusion, IFC selectively modulates tissue characteristics and thereby attenuates immune cell attraction and activation. Therefore, IFC treatment creates improved opportunities for cardiovascular graft preservation.

A Review of the Landscape of Targeted Immunomodulatory Therapies for Non-Infectious Uveitis

Systemic immunomodulatory therapies are the principal means of managing non-infectious uveitis. This review aims to explore the current landscape of systemic uveitis treatments, including biologic therapies and the advent of biosimilar therapies.

Rapid monocyte infiltration following retinal detachment is dependent on non-canonical IL6 signaling through gp130

BACKGROUND

Retinal detachment (RD) can lead to proliferative vitreoretinopathy (PVR), a leading cause of intractable vision loss. PVR is associated with a cytokine storm involving common proinflammatory molecules like IL6, but little is known about the source and downstream signaling of IL6 and the consequences for the retina. Here, we investigated the early immune response and resultant cytokine signaling following RD in mice.

METHODS

RD was induced in C57BL/6 J and IL6 knockout mice, and the resulting inflammatory response was examined using immunohistochemistry and flow cytometry. Cytokines and signaling proteins of vitreous and retinas were quantified by multiple cytokine arrays and Western blotting. To attempt to block IL6 signaling, a neutralizing antibody of IL6 receptor α (IL6Rα) or IL6 receptor β (gp-130) was injected intravitreally immediately after RD.

RESULTS

Within one day of RD, bone marrow-derived Cd11b + monocytes had extravasated from the vasculature and lined the vitreal surface of the retina, while the microglia, the resident macrophages of the retina, were relatively unperturbed. Cytokine arrays and Western blot analysis revealed that this sterile inflammation did not cause activation of IL6 signaling in the neurosensory retina, but rather only in the vitreous and aqueous humor. Monocyte infiltration was inhibited by blocking gp130, but not by IL6 knockout or IL6Rα blockade.

CONCLUSIONS

Together, our results demonstrate that monocytes are the primary immune cell mediating the cytokine storm following RD, and that any resulting retinal damage is unlikely to be a direct result of retinal IL6 signaling, but rather gp130-mediated signaling in the monocytes themselves. These results suggest that RD should be treated immediately, and that gp130-directed therapies may prevent PVR and promote retinal healing.

Cytokines and T-Cell Homeostasis in HIV Infection

Untreated human immunodeficiency virus (HIV) infection is characterized by progressive CD4(+) T-cell depletion and CD8(+) T-cell expansion, and CD4(+) T-cell depletion is linked directly to the risk for opportunistic infections and infection-associated mortality. With suppression of HIV replication by antiretroviral therapy, circulating CD4(+) Tcell numbers typically improve while CD8(+) T-cell expansion persists, and both CD4(+) T-cell cytopenia and CD8(+) T-cell expansion are associated with morbidity and mortality. In this brief review, we report on the role that selected homeostatic and inflammatory cytokines may play both in the failure of CD4(+) T-cell restoration and the CD8(+) T-cell expansion that characterize HIV infection.

Intravitreal injection of anti-Interleukin (IL)-6 antibody attenuates experimental autoimmune uveitis in mice

PURPOSE

To evaluate the effect of an intravitreally applied anti-IL-6 antibody for the treatment of experimental autoimmune uveitis (EAU).

METHODS

EAU was induced in female B10.RIII mice by Inter-Photoreceptor-Binding-Protein (IRBP) in complete Freund's adjuvant, boosted by Pertussis toxin. Single blinded intravitreal injections of anti-IL-6 antibody were applied 5-7days as well as 8-10days (3day interval) after EAU induction into the randomized treatment eye and phosphate buffered saline (PBS) into the fellow control eye. Clinical and fluorescein angiography scoring (6 EAU grades) was done at each injection day and at enucleation day 14. Enucleated eyes were either scored histologically (6 EAU grades) or examined by ELISA for levels of IL-6, IL-17 and IL-6 soluble Receptor (sIL-6R).

RESULTS

Uveitis developed in all 12 mice. Clinical uveitis score was significantly reduced (p=0.035) in treated eyes (median 2.0, range 0-4.0, n=12) compared to the fellow control eyes (median 3.0, range 1.0-4.0, n=12). Angiography scores were reduced in 9/12 treated eyes and histological scores in 3/4 treated eyes compared to the fellow control eyes. Cytokine levels were determined in 8 mice, of which 4 responded to anti-IL-6 treatment and 4 did not respond. All mice responding to treatment had a significant reduction of IL-6 (p<0.01) and IL-17 (p=0.01) levels in treated eyes compared to the fellow control eyes. This difference was not seen in non-responding mice.

CONCLUSIONS

Intravitreal anti-IL-6 treatment significantly attenuates experimental autoimmune uveitis in mice. EAU activity correlates with ocular IL-6 and IL-17 levels.

Cytokine Signatures in Mucocutaneous and Ocular Behçet's Disease

Behçet's disease (BD) is a multi-systemic inflammatory disorder consisting of recurrent oral aphthosis, genital ulcers, and chronic relapsing bilateral uveitis; however, many other organs may be affected. Several pro-inflammatory cytokines, mainly derived from Th1 and Th17 lymphocytes, seem to be involved in different pathogenic pathways leading to development of the clinical manifestations. On this basis, the primary aim of our study was to compare a core set of pro-inflammatory cytokines between patients with BD and healthy control (HC). The secondary goal was to evaluate potential correlations between these putative circulating biomarkers, the status of disease activity, and the specific organ involvement at the time of sample collection. Fifty-four serum samples were collected from 46 BD patients (17 males, 29 females, mean age 45.5 ± 11.3 years), and 19 HC (10 males, 9 females, mean age 43 ± 8.3 years). Twenty-five serum cytokines (APRIL/TNFS13, BAFF/TNFSF13B, sCD30/TNFRSF8, sCD163, Chitinase3-like1, gp130/sIL-6Rb, IFNb, sIL-6Ra, IL-10, IL-11, IL-19, IL-20, IL-26, IL-27 (p28), IL-28A/IFN-lambda2, IL-29/IFN-lambda1, IL-32, IL-34, IL-35, LIGHT/TNFSF-14, Pentraxin-3, sTNF-R1, sTNF-R2, TSLP, and TWEAK/TNFSF-12) were simultaneously quantified using a Bio-Rad cytokine bead arrays. Serum concentration of sTNF-R1 (p < 0.01) and sTNF-R2 (p < 0.01) resulted higher in both active and inactive BD than HC, while Chitinase3-like1 (p < 0.05) and gp130/sIL-6Rb (p < 0.01) serum levels were significantly higher in inactive BD, and IL-26 (p < 0.01) in active BD than HC. No differences were observed between inactive and active BD group. In addition, we observed that gp130/sIL-6Rb, sIL-6Ra, IL-35, and TSLP serum levels were significantly enhanced in patients with mucocutaneous manifestations plus ocular involvement (MO-BD) compared to subgroup with only mucocutaneous involvement (M-BD). Our findings may suggest a signature of IL-6, tumor necrosis factor-α as well as of Th17 response in BD patients due to increased levels of gp130/sIL-6Rb, sTNF-R1, sTNF-R2, IL-26, respectively. This evidence could contribute to improve the knowledge regarding the role of these citokines in the induction of specific BD clinical features.

Protein Tyrosine Phosphatase N2 Is a Positive Regulator of Lipopolysaccharide Signaling in Raw264.7 Cell through Derepression of Src Tyrosine Kinase

T cell protein tyrosine phosphatase N2 (PTPN2) is a phosphotyrosine-specific nonreceptor phosphatase and is ubiquitously expressed in tissues. Although PTPN2 functions as an important regulator in different signaling pathways, it is still unclear what is specific target protein of PTPN2 and how is regulated in lipopolysaccharide (LPS)-induced inflammatory signaling pathway. Here, we found that PTPN2 deficiency downregulated the expression of LPS-mediated pro-inflammtory cytokine genes. Conversely, overexpression of PTPN2 in Raw264.7 cells enhanced the expression and secretion of those cytokines. The activation of MAPK and NF-κB signaling pathways by LPS was reduced in PTPN2-knockdowned cells and ectopic expression of PTPN2 reversed these effects. Furthermore, we found that PTNP2 directly interacted with Src and removed the inhibitory Tyr527 phosphorylation of Src to enhance the activatory phosphorylation of Tyr416 residue. These results suggested that PTPN2 is a positive regulator of LPS-induced inflammatory response by enhancing the activity of Src through targeting the inhibitory phosphor-tyrosine527 of Src.

A novel intrinsically disordered outer membrane lipoprotein of Aggregatibacter actinomycetemcomitans binds various cytokines and plays a role in biofilm response to interleukin-1β and interleukin-8

Intrinsically disordered proteins (IDPs) do not have a well-defined and stable 3-dimensional fold. Some IDPs can function as either transient or permanent binders of other proteins and may interact with an array of ligands by adopting different conformations. A novel outer membrane lipoprotein, bacterial interleukin receptor I (BilRI) of the opportunistic oral pathogen Aggregatibacter actinomycetemcomitans binds a key gatekeeper proinflammatory cytokine interleukin (IL)-1β. Because the amino acid sequence of the novel lipoprotein resembles that of fibrinogen binder A of Haemophilus ducreyi, BilRI could have the potential to bind other proteins, such as host matrix proteins. However, from the tested host matrix proteins, BilRI interacted with neither collagen nor fibrinogen. Instead, the recombinant non-lipidated BilRI, which was intrinsically disordered, bound various pro/anti-inflammatory cytokines, such as IL-8, tumor necrosis factor (TNF)-α, interferon (IFN)-γ and IL-10. Moreover, BilRI played a role in the in vitro sensing of IL-1β and IL-8 because low concentrations of cytokines did not decrease the amount of extracellular DNA in the matrix of bilRI⁻ mutant biofilm as they did in the matrix of wild-type biofilm when the biofilms were exposed to recombinant cytokines for 22 hours. BilRI played a role in the internalization of IL-1β in the gingival model system but did not affect either IL-8 or IL-6 uptake. However, bilRI deletion did not entirely prevent IL-1β internalization, and the binding of cytokines to BilRI was relatively weak. Thus, BilRI might sequester cytokines on the surface of A. actinomycetemcomitans to facilitate the internalization process in low local cytokine concentrations.

Drug discovery in ophthalmology: past success, present challenges, and future opportunities

BACKGROUND

Drug discovery has undergone major transformations in the last century, progressing from the recognition and refinement of natural products with therapeutic benefit, to the systematic screening of molecular libraries on whole organisms or cell lines and more recently to a more target-based approach driven by greater knowledge of the physiological and pathological pathways involved. Despite this evolution increasing challenges within the drug discovery industry are causing escalating rates of failure of development pipelines.

DISCUSSION

We review the challenges facing the drug discovery industry, and discuss what attempts are being made to increase the productivity of drug development, including a refocusing on the study of the basic biology of the disease, and an embracing of the concept of 'translational research'. We consider what ophthalmic drug discovery can learn from the sector in general and discuss strategies to overcome the present limitations. This includes advances in the understanding of the pathogenesis of disease; improvements in animal models of human disease; improvements in ophthalmic drug delivery and attempts at patient stratification within clinical trials. As we look to the future, we argue that investment in ophthalmic drug development must continue to cover the whole translational spectrum (from 'bench to bedside and back again') with recognition that both biological discovery and clinical understanding will drive drug discovery, providing safe and effective therapies for ocular disease.

Fuchs' Uveitis Syndrome: No Longer a Syndrome?

PURPOSE

Rubella virus (RV) has a central role in the etiopathogenesis of Fuchs' uveitis syndrome (FUS). We aim to offer new insights by comprehensive analysis of recent laboratory and epidemiologic data.

METHODS

We conducted a literature search for laboratory data and papers on etiopathogenesis.

RESULTS

Aqueous humour samples of FUS patients show immunoreactivity to RV, in a specific and sensitive manner. Identification of RV genome confirm intraocular infection in a subset of FUS patients. Epidemiologic findings further support causality. The clinical spectrum of RV-associated uveitis is similar but not identical to FUS. FUS eyes exhibit a predominance of CD8 + T cells, high IFN-? and IL-10 levels.

CONCLUSIONS

RV is the leading cause of FUS. Cytokine-based findings mirror a viral etiology and chronic low-grade inflammation. RV-associated FUS represents a common pathway of intraocular RV inoculation after congenital or acquired infection. Other causes, including HSV and CMV, may lead to FUS.

Long-term lung transplantation in nonhuman primates

Despite advances in surgical technique and clinical care, lung transplantation still remains a short-term solution for the treatment of end-stage lung disease. To date, there has been limited experience in experimental lung transplantation using nonhuman primate models. Therefore, we have endeavored to develop a long-term, nonhuman primate model of orthotopic lung transplantation for the ultimate purpose of designing protocols to induce tolerance of lung grafts. Here, we report our initial results in developing this model and our observation that the nonhuman primate lung is particularly prone to rejection. This propensity toward rejection may be a consequence of 1) upregulated nonspecific inflammation, and 2) a larger number of pre-existing alloreactive memory T cells, leading to augmented deleterious immune responses. Our data show that triple-drug immunosuppression mimicking clinical practice is not sufficient to prevent acute rejection in nonhuman primate lung transplantation. The addition of horse-derived anti-thymocyte globulin and a monoclonal antibody to the IL-6 receptor allowed six out of six lung recipients to be free of rejection for over 120 days.

Role of dendritic cell subsets in immunity and their contribution to noninfectious uveitis

Dendritic cells (DCs) are a heterogeneous population. Murine DCs consist of conventional DCs (cDCs) and plasmacytoid DCs (pDCs). In humans, the analogous populations are myeloid DCs (mDCs) and pDCs. Though distinct in phenotypes and functions, studies have shown that these DC subsets may interact or "crosstalk" during immune responses. For example, cDCs may facilitate pDC maturation, and pDCs may enhance antigen presentation of cDCs in certain pathogenic conditions or even take on a cDC phenotype themselves. The role of DCs in noninfectious uveitis has been studied primarily in the experimental autoimmune uveitis mouse model and to a more limited extent in patients. Recent evidence shows that the number, phenotype, and function of DC subsets are altered in this disease. We provide an overview of selected recent developments of pDCs and cDCs/mDCs, with special attention to their interaction and the dual roles of DC subsets in noninfectious uveitis.

The varying faces of IL-6: From cardiac protection to cardiac failure

IL6 is a pleiotropic cytokine that is made in response to perturbations in homeostasis. IL6 becomes elevated in the acute response to host injury and can activate immune cells, direct immune cell trafficking, signal protective responses in local tissue, initial the acute phase response or initiate wound healing. In the short term this proinflammatory response is protective and limits host damage. It is when this acute response remains chronically activated that IL6 becomes pathogenic to the host. Chronically elevated IL6 levels lead to chronic inflammation and fibrotic disorders. The heart is a tissue where this temporal regulation of IL6 is very apparent. Studies from myocardial infarction show how short-term IL6 signaling can protect and preserve the heart tissue in response to acute damage, where long term IL6 signaling or an over-production of IL6R protein plays a causal role in cardiovascular disease. Thus, IL6 can be both protective and pathogenic, depending on the kinetics of the host response.

Pharmacotherapy for uveitis: current management and emerging therapy

Uveitis, a group of conditions characterized by intraocular inflammation, is a major cause of sight loss in the working population. Most uveitis seen in Western countries is noninfectious and appears to be autoimmune or autoinflammatory in nature, requiring treatment with immunosuppressive and/or anti-inflammatory drugs. In this educational review, we outline the ideal characteristics of drugs for uveitis and review the data to support the use of current and emerging therapies in this context. It is crucial that we continue to develop new therapies for use in uveitis that aim to suppress disease activity, prevent accumulation of damage, and preserve visual function for patients with the minimum possible side effects.

Transgene IL-6 enhances DC-stimulated CTL responses by counteracting CD4+25+Foxp3+ regulatory T cell suppression via IL-6-induced Foxp3 downregulation

Dendritic cells (DCs), the most potent antigen-presenting cells have been extensively applied in clinical trials for evaluation of antitumor immunity. However, the efficacy of DC-mediated cancer vaccines is still limited as they are unable to sufficiently break the immune tolerance. In this study, we constructed a recombinant adenoviral vector (AdVIL-6) expressing IL-6, and generated IL-6 transgene-engineered DC vaccine (DCOVA/IL-6) by transfection of murine bone marrow-derived ovalbumin (OVA)-pulsed DCs (DCOVA) with AdVIL-6. We then assessed DCOVA/IL-6-stimulated cytotoxic T-lymphocyte (CTL) responses and antitumor immunity in OVA-specific animal tumor model. We demonstrate that DCOVA/IL-6 vaccine up-regulates expression of DC maturation markers, secretes transgene-encoded IL-6, and more efficiently stimulates OVA-specific CTL responses and therapeutic immunity against OVA-expressing B16 melanoma BL6-10OVA in vivo than the control DCOVA/Null vaccine. Moreover, DCOVA/IL-6-stimulated CTL responses were relatively maintained in mice with transfer of CD4+25+Foxp3+ Tr-cells, but significantly reduced when treated with anti-IL-6 antibody. In addition, we demonstrate that IL-6 down-regulates Foxp3-expression of CD4+25+Foxp3+ Tr-cells in vitro. Taken together, our results demonstrate that AdV-mediated IL-6 transgene-engineered DC vaccine stimulates potent CTL responses and antitumor immunity by counteracting CD4+25+ Tr immunosuppression via IL-6-induced Foxp3 down-regulation. Thus, IL-6 may be a good candidate for engineering DCs for cancer immunotherapy.

Aqueous humor suppression of dendritic cell function helps maintain immune regulation in the eye during human uveitis

PURPOSE

Noninfectious uveitis is characterized by a dysregulated inflammatory or immune response in the eye. It is unclear whether this represents a failure of immune privilege or an overwhelming inflammatory drive that has exceeded the capacity of regulatory mechanisms that are still functioning. The authors investigated immune regulation in the human eye during intraocular inflammation (uveitis) and its impact on dendritic cell (DC) function and subsequent T-cell responses.

METHODS

Myeloid DCs were isolated from the aqueous humor (AqH) and peripheral blood of patients with active uveitis and characterized by flow cytometry. The effect of uveitis AqH was interrogated in an in vitro model of peripheral blood monocyte-derived DCs from healthy controls.

RESULTS

Myeloid DCs isolated from uveitic AqH were characterized by elevated major histocompatibility complex classes I and II (MHC I/II), but reduced CD86 compared with matched peripheral blood DCs. Exposure of peripheral blood monocyte-derived DCs from healthy controls to the inflammatory AqH supernatant recapitulated this phenotype. Despite interferon gamma (IFNγ)-dependent upregulation of MHC I, inflammatory AqH was overall suppressive to DC function, with reduced CD86 expression and diminished T-cell responses. This suppressive effect was equal to or greater than that induced by noninflammatory AqH, but was glucocorticoid independent (in contrast to noninflammatory AqH).

CONCLUSIONS

These data indicate that the ocular microenvironment continues to regulate DC function during uveitis, despite IFNγ-driven upregulation of MHC expression, supporting the hypothesis that immune regulation within the eye is maintained during inflammation.

The many faces of interleukin-6: the role of IL-6 in inflammation, vasculopathy, and fibrosis in systemic sclerosis

Interleukin-6 is currently attracting significant interest as a potential therapeutic target in systemic sclerosis (SSc). In this paper, the biology of interleukin-6 is reviewed, and the evidence for interleukin-6 dysregulation in SSc is explored. The role of inteleukin-6 classical and trans signalling pathways in SSc relevant phenomena such as chronic inflammation, autoimmunity, endothelial cell dysfunction, and fibrogenesis is discussed. The existing evidence that interventions designed to block interleukin-6 signalling are of therapeutic relevance in SSc is evaluated.